diff --git a/PKGBUILD b/PKGBUILD new file mode 100644 index 0000000..363c415 --- /dev/null +++ b/PKGBUILD @@ -0,0 +1,515 @@ +# Maintainer: xduugu +_pkgext=-spica +pkgbase=linux$_pkgext +pkgname=$pkgbase + +# required by AUR +# comment the following line to build a single package containing the kernel and the headers +(( 1 )) && pkgname=("$pkgbase" "$pkgbase-headers" "$pkgbase-docs") +pkgdesc="The Linux Kernel and modules from Linus' git tree" +depends=('coreutils' 'linux-firmware-git' 'mkinitcpio') + +pkgver=4.5.rc4 +pkgrel=1 +url="http://www.kernel.org/" +arch=(i686 x86_64) +license=('GPL2') +makedepends=(git bc) +options=(!strip) +source=($pkgname::git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git) +md5sums=('SKIP') +sha256sums=('SKIP') + +# set _gitrev to a git revision (man gitrevisions) like a tag, a commit sha1 +# hash or a branch name to build from this tree instead of master + +_gitrev="v4.4" + +#################################################################### +# KERNEL CONFIG FILES +# +# This PKGBUILD searches for config files in the current directory +# and will use the first one it finds from the following +# list as base configuration: +# config.local +# config.saved.$CARCH +# config.$CARCH +# +#################################################################### + + +############################################################# +# PATCHES +# +# This package builds the vanilla git kernel by default, +# but it is possible to patch the source without modifying +# this PKGBUILD. +# +# Simply create a directory 'patches' in your PKGBUILD +# directory and _any_ file (dotfiles excluded) in this +# folder will be applied to the kernel source. +# +# Prefixing the patch file names with dots will obviously +# excluded them from the patching process. +# +############################################################# + + +############################# +# CONFIGURATION +# +# Uncomment desired options +############################# +#_make_modules=0 + +MAKEFLAGS="-j $(expr $(cat /proc/cpuinfo |grep processor |wc -l) \* 2)" +####### +# Set to e.g. menuconfig, xconfig or gconfig +# +# For a full list of supported commands, please have a look +# at "Configuration targets" section of `make help`'s output +# or the help target in scripts/kconfig/Makefile +# http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=blob;f=scripts/kconfig/Makefile +# +# If unset or set to an empty or space-only string, the +# (manual) kernel configuration step will be skipped. +# +_config_cmd="${_config_cmd:-menuconfig}" +#_config_cmd="${_config_cmd:-oldconfig}" + + +####### +# Stop build process after kernel configuration +# +# This option enables _save_config implicitly. +# +# _configure_only=1 + + +####### +# Append the date to the localversion +# +# e.g. -ARCH -> -ARCH-20090422 +# +# _date_localversion=1 + + +####### +# Save the .config file to package directory +# as config.saved.$CARCH +# +_save_config=1 + + +####### +# Do not compress kernel modules +# +# _no_modules_compression=1 + + +####### +# Make the kernel build process verbose +# +# _verbose=1 + + +# internal variables +(( 1 )) && _kernel_src="$pkgname" +#(( 1 )) && _kernel_src="$BUILDDIR/$(find . -maxdepth 1 -type d -name "linux-*" -printf "%f\n" | head -1)" + +####### +# define required functions + +pkgver() { + cd "$_kernel_src" + git describe --always | sed 's/^v//;s/-/./g' +} + +# single package +package() { + eval package_$pkgbase-headers + eval package_$pkgbase +} + +# split package functions +eval "package_$pkgbase() { _generic_package_linux; }" +eval "package_$pkgbase-headers() { _generic_package_linux-headers; }" +eval "package_$pkgbase-docs() { _generic_package_linux-docs; }" + + +############################## +# where the magic happens... +############################## +build() { + cd "$_kernel_src" + msg "Sanitizing source tree.." + [[ -n $_gitrev ]] && git reset --hard "$_gitrev" + # cleaning source trees + git clean -f + + ################# + # Apply patches + ################# + msg "Applying patches..." + local i patches + for i in "${source[@]}"; do + i=${i##*/} + [[ $i =~ .*\.patch$ ]] && patches=("${patches[@]}" "$srcdir/$i") + [[ ${i%.*} =~ .*\.patch$ ]] && patches=("${patches[@]}" "$srcdir/${i%.*}") + done + + shopt -s nullglob + for i in "${patches[@]}" "$startdir/patches/"*; do + msg2 "Applying ${i##*/}..." + patch -Np1 -i "$i" || (error "Applying ${i##*/} failed" && return 1) + done + shopt -u nullglob + + + ################# + # CONFIGURATION + ################# + + ######################### + # Loading configuration + ######################### + msg "Loading configuration..." + for i in local "saved.$CARCH" "$CARCH"; do + if [[ -e $startdir/config.$i ]]; then + msg2 "Using kernel config file config.$i..." + cp -f "$startdir/config.$i" .config + break + fi + done + + [[ ! -e .config ]] && + warning "No suitable kernel config file was found. You'll have to configure the kernel from scratch." + + + ########################### + # Start the configuration + ########################### + msg "Updating configuration..." + yes "" | make config > /dev/null + + if [[ -f "$startdir/config.saved.$CARCH" ]]; then + msg2 "migrating previous config..." + cp "$startdir/config.saved.$CARCH" .config + make oldconfig + else + msg2 "migrating default config..." + cp "$startdir/config.$CARCH" .config + make oldconfig + fi + if [[ -n ${_config_cmd// /} ]]; then + msg2 "Running make $_config_cmd..." + make $_config_cmd + else + warning "Unknown config command: $_config_cmd" + fi + + ############################################## + # Save the config file the package directory + ############################################## + if [[ -n $_save_config || -n $_configure_only ]]; then + msg "Saving configuration..." + msg2 "Saving $_kernel_src/.config as $startdir/config.saved.$CARCH" + cp .config "$startdir/config.saved.$CARCH" + fi + + + ####################################### + # Stop after configuration if desired + ####################################### + if [[ -n $_configure_only ]]; then + rm -rf "$srcdir" "$pkgdir" + return 1 + fi + + + ############################### + # Append date to localversion + ############################### + if [[ -n $_date_localversion ]]; then + local _localversion="$(sed -rn 's/^CONFIG_LOCALVERSION="([^"]*)"$/\1/p' .config)" + [[ -n $_localversion ]] && msg2 "CONFIG_LOCALVERSION is set to: $_localversion" + + # since this is a git package, the $pkgver is equal to $(date +%Y%m%d) + msg2 "Appending $pkgver to CONFIG_LOCALVERSION..." + sed -ri "s/^(CONFIG_LOCALVERSION=).*$/\1\"$_localversion-$pkgver\"/" .config + fi + + + #################################### + # Append pkgrel to kernel version + #################################### + sed -ri "s/^(EXTRAVERSION =).*$/\1 -$pkgrel/" Makefile + + + #################################### + # don't run depmod on 'make install' + #################################### + sed -i '2iexit 0' scripts/depmod.sh + git update-index --assume-unchanged scripts/depmod.sh + + + ################# + # BUILD PROCESS + ################# + + ################################ + # Build the kernel and modules + ################################ + msg "Building kernel and modules..." +if [[ -n $_make_modules ]]; then + make $MAKEFLAGS V="$_verbose" bzImage modules +else + make $MAKEFLAGS V="$_verbose" bzImage +fi +} + + +_generic_package_initialization() { + cd "$srcdir/${_kernel_src##*/}" + + _karch="x86" + + ###################### + # Get kernel version + ###################### + _kernver=$(make kernelrelease) + _basekernver=${_kernver%%-*} +} + +_generic_package_linux() { + pkgdesc="The Linux Kernel and modules from Linus' git tree" + backup=(etc/mkinitcpio.d/$pkgname.preset) + install=$pkgname.install + changelog=$pkgname.changelog + + # set required variables + _generic_package_initialization + + + ############################################################# + # Provide linux + # (probably someone wants to use this kernel exclusively?) + ############################################################# + provides=("${provides[@]}" "linux=${_kernver//-/_}") + + ################ + # INSTALLATION + ################ + + ##################### + # Install the image + ##################### + msg "Installing kernel image..." + install -Dm644 arch/$_karch/boot/bzImage "$pkgdir/boot/vmlinuz-$pkgname" + + + ########################## + # Install kernel modules + ########################## + msg "Installing kernel modules..." + if [[ -n $_make_modules ]]; then + # force -j1 to work around make 3.82 bug + make -j1 INSTALL_MOD_PATH="$pkgdir/usr" modules_install + [[ -z $_no_modules_compression ]] && find "$pkgdir" -name "*.ko" -exec gzip -9 {} + + + ######################################################### + # Set up extramodules directory (for external modules) + ######################################################### + local extramodules="$pkgdir/usr/lib/modules/extramodules-$(cut -d. -f1,2 <<<$_basekernver)" + local modversion=$(grep '^CONFIG_LOCALVERSION=' .config | cut -d'"' -f2) + [[ -n $modversion ]] && extramodules+=$modversion + install -dm755 "${extramodules}${_pkgext}" + echo $_kernver > "${extramodules}${_pkgext}/version" + ln -s "../${extramodules##*/}${_pkgext}" "$pkgdir/usr/lib/modules/$_kernver/extramodules" + + + ################################## + # Create important symlinks + ################################## + msg "Creating important symlinks..." + + # Create generic modules symlink + if [[ $_kernver != ${_basekernver}${_pkgext} ]]; then + cd "$pkgdir/usr/lib/modules" + ln -s "$_kernver" "${_basekernver}${_pkgext}" + cd "$OLDPWD" + fi + + # remove header symlinks + cd "$pkgdir/usr/lib/modules/$_kernver" + rm -rf source build + cd "$OLDPWD" + fi + + + ############################ + # Install mkinitcpio files + ############################ + install -d "$pkgdir/etc/mkinitcpio.d" + + msg "Generating $pkgname.preset..." + cat > "$pkgdir/etc/mkinitcpio.d/$pkgname.preset" <" + echo "> Updating module dependencies. Please wait ..." + depmod $kernver + + echo ">" + echo "> Generating initramfs, using mkinitcpio. Please wait..." + echo ">" + mkinitcpio -p $pkgname + echo "> Modifing efibootmgr..." + efibootmgr|awk 'match($0,/^Boot([0-9a-fA-F]{4})\* spi-ca_v(.+)$/,m){printf "efibootmgr -b %s -B;echo \">> remove entry : %s\";",m[1],m[2]}'|sh + echo "> Copy efistub from boot" + cp -fv "boot/vmlinuz-$pkgname" "boot/efi/EFI/spi-ca/kernel.efi" + cp -fv "boot/initramfs-$pkgname.img" "boot/efi/EFI/spi-ca/initrd" + echo "> Registering efistub " + #echo 'efibootmgr -c -g -d /dev/sda -p 1 -L "spi-ca_v$kernver" -l "\EFI\spi-ca\kernel.efi" #-u "$bootdevice $option"' + efibootmgr -c -g -d /dev/sde -p 1 -L "spi-ca_v$kernver" -l "\EFI\spi-ca\kernel" # -u "$bootdevice $option" + echo "> Reordering Bootorder..." + newentry=`efibootmgr|awk 'match($0,/^Boot([0-9a-fA-F]{4})\* spi-ca_v(.+)$/,m){print m[1]}'` + prebootorder=`efibootmgr |grep BootOrder |cut -d : -f 2 |tr -d ' '` + efibootmgr -O + efibootmgr -o ${newentry},${prebootorder} + echo "> OK!" +} + +post_upgrade() { + post_install +} + +post_remove() { + rm -f -- "boot/initramfs-$pkgname.img" +} diff --git a/patches/0001-block-cgroups-kconfig-build-bits-for-BFQ-v7r10-4.4.0.patch b/patches/0001-block-cgroups-kconfig-build-bits-for-BFQ-v7r10-4.4.0.patch new file mode 100644 index 0000000..69a5662 --- /dev/null +++ b/patches/0001-block-cgroups-kconfig-build-bits-for-BFQ-v7r10-4.4.0.patch @@ -0,0 +1,103 @@ +From d54aac68a9655574a91e6d224300aba239ea58cc Mon Sep 17 00:00:00 2001 +From: Paolo Valente +Date: Tue, 7 Apr 2015 13:39:12 +0200 +Subject: [PATCH 1/3] block: cgroups, kconfig, build bits for BFQ-v7r10-4.4.0 + +Update Kconfig.iosched and do the related Makefile changes to include +kernel configuration options for BFQ. Also increase the number of +policies supported by the blkio controller so that BFQ can add its +own. + +Signed-off-by: Paolo Valente +Signed-off-by: Arianna Avanzini +--- + block/Kconfig.iosched | 32 ++++++++++++++++++++++++++++++++ + block/Makefile | 1 + + include/linux/blkdev.h | 2 +- + 3 files changed, 34 insertions(+), 1 deletion(-) + +diff --git a/block/Kconfig.iosched b/block/Kconfig.iosched +index 421bef9..0ee5f0f 100644 +--- a/block/Kconfig.iosched ++++ b/block/Kconfig.iosched +@@ -39,6 +39,27 @@ config CFQ_GROUP_IOSCHED + ---help--- + Enable group IO scheduling in CFQ. + ++config IOSCHED_BFQ ++ tristate "BFQ I/O scheduler" ++ default n ++ ---help--- ++ The BFQ I/O scheduler tries to distribute bandwidth among ++ all processes according to their weights. ++ It aims at distributing the bandwidth as desired, independently of ++ the disk parameters and with any workload. It also tries to ++ guarantee low latency to interactive and soft real-time ++ applications. If compiled built-in (saying Y here), BFQ can ++ be configured to support hierarchical scheduling. ++ ++config CGROUP_BFQIO ++ bool "BFQ hierarchical scheduling support" ++ depends on CGROUPS && IOSCHED_BFQ=y ++ default n ++ ---help--- ++ Enable hierarchical scheduling in BFQ, using the cgroups ++ filesystem interface. The name of the subsystem will be ++ bfqio. ++ + choice + prompt "Default I/O scheduler" + default DEFAULT_CFQ +@@ -52,6 +73,16 @@ choice + config DEFAULT_CFQ + bool "CFQ" if IOSCHED_CFQ=y + ++ config DEFAULT_BFQ ++ bool "BFQ" if IOSCHED_BFQ=y ++ help ++ Selects BFQ as the default I/O scheduler which will be ++ used by default for all block devices. ++ The BFQ I/O scheduler aims at distributing the bandwidth ++ as desired, independently of the disk parameters and with ++ any workload. It also tries to guarantee low latency to ++ interactive and soft real-time applications. ++ + config DEFAULT_NOOP + bool "No-op" + +@@ -61,6 +92,7 @@ config DEFAULT_IOSCHED + string + default "deadline" if DEFAULT_DEADLINE + default "cfq" if DEFAULT_CFQ ++ default "bfq" if DEFAULT_BFQ + default "noop" if DEFAULT_NOOP + + endmenu +diff --git a/block/Makefile b/block/Makefile +index 00ecc97..1ed86d5 100644 +--- a/block/Makefile ++++ b/block/Makefile +@@ -18,6 +18,7 @@ obj-$(CONFIG_BLK_DEV_THROTTLING) += blk-throttle.o + obj-$(CONFIG_IOSCHED_NOOP) += noop-iosched.o + obj-$(CONFIG_IOSCHED_DEADLINE) += deadline-iosched.o + obj-$(CONFIG_IOSCHED_CFQ) += cfq-iosched.o ++obj-$(CONFIG_IOSCHED_BFQ) += bfq-iosched.o + + obj-$(CONFIG_BLOCK_COMPAT) += compat_ioctl.o + obj-$(CONFIG_BLK_CMDLINE_PARSER) += cmdline-parser.o +diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h +index c70e358..ae43492 100644 +--- a/include/linux/blkdev.h ++++ b/include/linux/blkdev.h +@@ -44,7 +44,7 @@ struct pr_ops; + * Maximum number of blkcg policies allowed to be registered concurrently. + * Defined here to simplify include dependency. + */ +-#define BLKCG_MAX_POLS 2 ++#define BLKCG_MAX_POLS 3 + + struct request; + typedef void (rq_end_io_fn)(struct request *, int); +-- +1.9.1 + diff --git a/patches/0002-block-introduce-the-BFQ-v7r10-I-O-sched-for-4.4.0.patch b/patches/0002-block-introduce-the-BFQ-v7r10-I-O-sched-for-4.4.0.patch new file mode 100644 index 0000000..fa63968 --- /dev/null +++ b/patches/0002-block-introduce-the-BFQ-v7r10-I-O-sched-for-4.4.0.patch @@ -0,0 +1,7121 @@ +From e1db9f07f51ef6a8b1dfd2750cd45cb8f890ec7f Mon Sep 17 00:00:00 2001 +From: Paolo Valente +Date: Thu, 9 May 2013 19:10:02 +0200 +Subject: [PATCH 2/3] block: introduce the BFQ-v7r10 I/O sched for 4.4.0 + +Add the BFQ-v7r10 I/O scheduler to 4.4.0. +The general structure is borrowed from CFQ, as much of the code for +handling I/O contexts. Over time, several useful features have been +ported from CFQ as well (details in the changelog in README.BFQ). A +(bfq_)queue is associated to each task doing I/O on a device, and each +time a scheduling decision has to be made a queue is selected and served +until it expires. + + - Slices are given in the service domain: tasks are assigned + budgets, measured in number of sectors. Once got the disk, a task + must however consume its assigned budget within a configurable + maximum time (by default, the maximum possible value of the + budgets is automatically computed to comply with this timeout). + This allows the desired latency vs "throughput boosting" tradeoff + to be set. + + - Budgets are scheduled according to a variant of WF2Q+, implemented + using an augmented rb-tree to take eligibility into account while + preserving an O(log N) overall complexity. + + - A low-latency tunable is provided; if enabled, both interactive + and soft real-time applications are guaranteed a very low latency. + + - Latency guarantees are preserved also in the presence of NCQ. + + - Also with flash-based devices, a high throughput is achieved + while still preserving latency guarantees. + + - BFQ features Early Queue Merge (EQM), a sort of fusion of the + cooperating-queue-merging and the preemption mechanisms present + in CFQ. EQM is in fact a unified mechanism that tries to get a + sequential read pattern, and hence a high throughput, with any + set of processes performing interleaved I/O over a contiguous + sequence of sectors. + + - BFQ supports full hierarchical scheduling, exporting a cgroups + interface. Since each node has a full scheduler, each group can + be assigned its own weight. + + - If the cgroups interface is not used, only I/O priorities can be + assigned to processes, with ioprio values mapped to weights + with the relation weight = IOPRIO_BE_NR - ioprio. + + - ioprio classes are served in strict priority order, i.e., lower + priority queues are not served as long as there are higher + priority queues. Among queues in the same class the bandwidth is + distributed in proportion to the weight of each queue. A very + thin extra bandwidth is however guaranteed to the Idle class, to + prevent it from starving. + +Signed-off-by: Paolo Valente +Signed-off-by: Arianna Avanzini +--- + block/Kconfig.iosched | 6 +- + block/bfq-cgroup.c | 1203 ++++++++++++++++ + block/bfq-ioc.c | 36 + + block/bfq-iosched.c | 3753 +++++++++++++++++++++++++++++++++++++++++++++++++ + block/bfq-sched.c | 1197 ++++++++++++++++ + block/bfq.h | 807 +++++++++++ + 6 files changed, 6998 insertions(+), 4 deletions(-) + create mode 100644 block/bfq-cgroup.c + create mode 100644 block/bfq-ioc.c + create mode 100644 block/bfq-iosched.c + create mode 100644 block/bfq-sched.c + create mode 100644 block/bfq.h + +diff --git a/block/Kconfig.iosched b/block/Kconfig.iosched +index 0ee5f0f..f78cd1a 100644 +--- a/block/Kconfig.iosched ++++ b/block/Kconfig.iosched +@@ -51,14 +51,12 @@ config IOSCHED_BFQ + applications. If compiled built-in (saying Y here), BFQ can + be configured to support hierarchical scheduling. + +-config CGROUP_BFQIO ++config BFQ_GROUP_IOSCHED + bool "BFQ hierarchical scheduling support" + depends on CGROUPS && IOSCHED_BFQ=y + default n + ---help--- +- Enable hierarchical scheduling in BFQ, using the cgroups +- filesystem interface. The name of the subsystem will be +- bfqio. ++ Enable hierarchical scheduling in BFQ, using the blkio controller. + + choice + prompt "Default I/O scheduler" +diff --git a/block/bfq-cgroup.c b/block/bfq-cgroup.c +new file mode 100644 +index 0000000..707364a +--- /dev/null ++++ b/block/bfq-cgroup.c +@@ -0,0 +1,1203 @@ ++/* ++ * BFQ: CGROUPS support. ++ * ++ * Based on ideas and code from CFQ: ++ * Copyright (C) 2003 Jens Axboe ++ * ++ * Copyright (C) 2008 Fabio Checconi ++ * Paolo Valente ++ * ++ * Copyright (C) 2010 Paolo Valente ++ * ++ * Licensed under the GPL-2 as detailed in the accompanying COPYING.BFQ ++ * file. ++ */ ++ ++#ifdef CONFIG_BFQ_GROUP_IOSCHED ++ ++/* bfqg stats flags */ ++enum bfqg_stats_flags { ++ BFQG_stats_waiting = 0, ++ BFQG_stats_idling, ++ BFQG_stats_empty, ++}; ++ ++#define BFQG_FLAG_FNS(name) \ ++static void bfqg_stats_mark_##name(struct bfqg_stats *stats) \ ++{ \ ++ stats->flags |= (1 << BFQG_stats_##name); \ ++} \ ++static void bfqg_stats_clear_##name(struct bfqg_stats *stats) \ ++{ \ ++ stats->flags &= ~(1 << BFQG_stats_##name); \ ++} \ ++static int bfqg_stats_##name(struct bfqg_stats *stats) \ ++{ \ ++ return (stats->flags & (1 << BFQG_stats_##name)) != 0; \ ++} \ ++ ++BFQG_FLAG_FNS(waiting) ++BFQG_FLAG_FNS(idling) ++BFQG_FLAG_FNS(empty) ++#undef BFQG_FLAG_FNS ++ ++/* This should be called with the queue_lock held. */ ++static void bfqg_stats_update_group_wait_time(struct bfqg_stats *stats) ++{ ++ unsigned long long now; ++ ++ if (!bfqg_stats_waiting(stats)) ++ return; ++ ++ now = sched_clock(); ++ if (time_after64(now, stats->start_group_wait_time)) ++ blkg_stat_add(&stats->group_wait_time, ++ now - stats->start_group_wait_time); ++ bfqg_stats_clear_waiting(stats); ++} ++ ++/* This should be called with the queue_lock held. */ ++static void bfqg_stats_set_start_group_wait_time(struct bfq_group *bfqg, ++ struct bfq_group *curr_bfqg) ++{ ++ struct bfqg_stats *stats = &bfqg->stats; ++ ++ if (bfqg_stats_waiting(stats)) ++ return; ++ if (bfqg == curr_bfqg) ++ return; ++ stats->start_group_wait_time = sched_clock(); ++ bfqg_stats_mark_waiting(stats); ++} ++ ++/* This should be called with the queue_lock held. */ ++static void bfqg_stats_end_empty_time(struct bfqg_stats *stats) ++{ ++ unsigned long long now; ++ ++ if (!bfqg_stats_empty(stats)) ++ return; ++ ++ now = sched_clock(); ++ if (time_after64(now, stats->start_empty_time)) ++ blkg_stat_add(&stats->empty_time, ++ now - stats->start_empty_time); ++ bfqg_stats_clear_empty(stats); ++} ++ ++static void bfqg_stats_update_dequeue(struct bfq_group *bfqg) ++{ ++ blkg_stat_add(&bfqg->stats.dequeue, 1); ++} ++ ++static void bfqg_stats_set_start_empty_time(struct bfq_group *bfqg) ++{ ++ struct bfqg_stats *stats = &bfqg->stats; ++ ++ if (blkg_rwstat_total(&stats->queued)) ++ return; ++ ++ /* ++ * group is already marked empty. This can happen if bfqq got new ++ * request in parent group and moved to this group while being added ++ * to service tree. Just ignore the event and move on. ++ */ ++ if (bfqg_stats_empty(stats)) ++ return; ++ ++ stats->start_empty_time = sched_clock(); ++ bfqg_stats_mark_empty(stats); ++} ++ ++static void bfqg_stats_update_idle_time(struct bfq_group *bfqg) ++{ ++ struct bfqg_stats *stats = &bfqg->stats; ++ ++ if (bfqg_stats_idling(stats)) { ++ unsigned long long now = sched_clock(); ++ ++ if (time_after64(now, stats->start_idle_time)) ++ blkg_stat_add(&stats->idle_time, ++ now - stats->start_idle_time); ++ bfqg_stats_clear_idling(stats); ++ } ++} ++ ++static void bfqg_stats_set_start_idle_time(struct bfq_group *bfqg) ++{ ++ struct bfqg_stats *stats = &bfqg->stats; ++ ++ stats->start_idle_time = sched_clock(); ++ bfqg_stats_mark_idling(stats); ++} ++ ++static void bfqg_stats_update_avg_queue_size(struct bfq_group *bfqg) ++{ ++ struct bfqg_stats *stats = &bfqg->stats; ++ ++ blkg_stat_add(&stats->avg_queue_size_sum, ++ blkg_rwstat_total(&stats->queued)); ++ blkg_stat_add(&stats->avg_queue_size_samples, 1); ++ bfqg_stats_update_group_wait_time(stats); ++} ++ ++static struct blkcg_policy blkcg_policy_bfq; ++ ++/* ++ * blk-cgroup policy-related handlers ++ * The following functions help in converting between blk-cgroup ++ * internal structures and BFQ-specific structures. ++ */ ++ ++static struct bfq_group *pd_to_bfqg(struct blkg_policy_data *pd) ++{ ++ return pd ? container_of(pd, struct bfq_group, pd) : NULL; ++} ++ ++static struct blkcg_gq *bfqg_to_blkg(struct bfq_group *bfqg) ++{ ++ return pd_to_blkg(&bfqg->pd); ++} ++ ++static struct bfq_group *blkg_to_bfqg(struct blkcg_gq *blkg) ++{ ++ return pd_to_bfqg(blkg_to_pd(blkg, &blkcg_policy_bfq)); ++} ++ ++/* ++ * bfq_group handlers ++ * The following functions help in navigating the bfq_group hierarchy ++ * by allowing to find the parent of a bfq_group or the bfq_group ++ * associated to a bfq_queue. ++ */ ++ ++static struct bfq_group *bfqg_parent(struct bfq_group *bfqg) ++{ ++ struct blkcg_gq *pblkg = bfqg_to_blkg(bfqg)->parent; ++ ++ return pblkg ? blkg_to_bfqg(pblkg) : NULL; ++} ++ ++static struct bfq_group *bfqq_group(struct bfq_queue *bfqq) ++{ ++ struct bfq_entity *group_entity = bfqq->entity.parent; ++ ++ return group_entity ? container_of(group_entity, struct bfq_group, ++ entity) : ++ bfqq->bfqd->root_group; ++} ++ ++/* ++ * The following two functions handle get and put of a bfq_group by ++ * wrapping the related blk-cgroup hooks. ++ */ ++ ++static void bfqg_get(struct bfq_group *bfqg) ++{ ++ return blkg_get(bfqg_to_blkg(bfqg)); ++} ++ ++static void bfqg_put(struct bfq_group *bfqg) ++{ ++ return blkg_put(bfqg_to_blkg(bfqg)); ++} ++ ++static void bfqg_stats_update_io_add(struct bfq_group *bfqg, ++ struct bfq_queue *bfqq, ++ int rw) ++{ ++ blkg_rwstat_add(&bfqg->stats.queued, rw, 1); ++ bfqg_stats_end_empty_time(&bfqg->stats); ++ if (!(bfqq == ((struct bfq_data *)bfqg->bfqd)->in_service_queue)) ++ bfqg_stats_set_start_group_wait_time(bfqg, bfqq_group(bfqq)); ++} ++ ++static void bfqg_stats_update_io_remove(struct bfq_group *bfqg, int rw) ++{ ++ blkg_rwstat_add(&bfqg->stats.queued, rw, -1); ++} ++ ++static void bfqg_stats_update_io_merged(struct bfq_group *bfqg, int rw) ++{ ++ blkg_rwstat_add(&bfqg->stats.merged, rw, 1); ++} ++ ++static void bfqg_stats_update_dispatch(struct bfq_group *bfqg, ++ uint64_t bytes, int rw) ++{ ++ blkg_stat_add(&bfqg->stats.sectors, bytes >> 9); ++ blkg_rwstat_add(&bfqg->stats.serviced, rw, 1); ++ blkg_rwstat_add(&bfqg->stats.service_bytes, rw, bytes); ++} ++ ++static void bfqg_stats_update_completion(struct bfq_group *bfqg, ++ uint64_t start_time, uint64_t io_start_time, int rw) ++{ ++ struct bfqg_stats *stats = &bfqg->stats; ++ unsigned long long now = sched_clock(); ++ ++ if (time_after64(now, io_start_time)) ++ blkg_rwstat_add(&stats->service_time, rw, now - io_start_time); ++ if (time_after64(io_start_time, start_time)) ++ blkg_rwstat_add(&stats->wait_time, rw, ++ io_start_time - start_time); ++} ++ ++/* @stats = 0 */ ++static void bfqg_stats_reset(struct bfqg_stats *stats) ++{ ++ if (!stats) ++ return; ++ ++ /* queued stats shouldn't be cleared */ ++ blkg_rwstat_reset(&stats->service_bytes); ++ blkg_rwstat_reset(&stats->serviced); ++ blkg_rwstat_reset(&stats->merged); ++ blkg_rwstat_reset(&stats->service_time); ++ blkg_rwstat_reset(&stats->wait_time); ++ blkg_stat_reset(&stats->time); ++ blkg_stat_reset(&stats->unaccounted_time); ++ blkg_stat_reset(&stats->avg_queue_size_sum); ++ blkg_stat_reset(&stats->avg_queue_size_samples); ++ blkg_stat_reset(&stats->dequeue); ++ blkg_stat_reset(&stats->group_wait_time); ++ blkg_stat_reset(&stats->idle_time); ++ blkg_stat_reset(&stats->empty_time); ++} ++ ++/* @to += @from */ ++static void bfqg_stats_merge(struct bfqg_stats *to, struct bfqg_stats *from) ++{ ++ if (!to || !from) ++ return; ++ ++ /* queued stats shouldn't be cleared */ ++ blkg_rwstat_add_aux(&to->service_bytes, &from->service_bytes); ++ blkg_rwstat_add_aux(&to->serviced, &from->serviced); ++ blkg_rwstat_add_aux(&to->merged, &from->merged); ++ blkg_rwstat_add_aux(&to->service_time, &from->service_time); ++ blkg_rwstat_add_aux(&to->wait_time, &from->wait_time); ++ blkg_stat_add_aux(&from->time, &from->time); ++ blkg_stat_add_aux(&to->unaccounted_time, &from->unaccounted_time); ++ blkg_stat_add_aux(&to->avg_queue_size_sum, &from->avg_queue_size_sum); ++ blkg_stat_add_aux(&to->avg_queue_size_samples, &from->avg_queue_size_samples); ++ blkg_stat_add_aux(&to->dequeue, &from->dequeue); ++ blkg_stat_add_aux(&to->group_wait_time, &from->group_wait_time); ++ blkg_stat_add_aux(&to->idle_time, &from->idle_time); ++ blkg_stat_add_aux(&to->empty_time, &from->empty_time); ++} ++ ++/* ++ * Transfer @bfqg's stats to its parent's dead_stats so that the ancestors' ++ * recursive stats can still account for the amount used by this bfqg after ++ * it's gone. ++ */ ++static void bfqg_stats_xfer_dead(struct bfq_group *bfqg) ++{ ++ struct bfq_group *parent; ++ ++ if (!bfqg) /* root_group */ ++ return; ++ ++ parent = bfqg_parent(bfqg); ++ ++ lockdep_assert_held(bfqg_to_blkg(bfqg)->q->queue_lock); ++ ++ if (unlikely(!parent)) ++ return; ++ ++ bfqg_stats_merge(&parent->dead_stats, &bfqg->stats); ++ bfqg_stats_merge(&parent->dead_stats, &bfqg->dead_stats); ++ bfqg_stats_reset(&bfqg->stats); ++ bfqg_stats_reset(&bfqg->dead_stats); ++} ++ ++static void bfq_init_entity(struct bfq_entity *entity, ++ struct bfq_group *bfqg) ++{ ++ struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); ++ ++ entity->weight = entity->new_weight; ++ entity->orig_weight = entity->new_weight; ++ if (bfqq) { ++ bfqq->ioprio = bfqq->new_ioprio; ++ bfqq->ioprio_class = bfqq->new_ioprio_class; ++ bfqg_get(bfqg); ++ } ++ entity->parent = bfqg->my_entity; ++ entity->sched_data = &bfqg->sched_data; ++} ++ ++static void bfqg_stats_exit(struct bfqg_stats *stats) ++{ ++ blkg_rwstat_exit(&stats->service_bytes); ++ blkg_rwstat_exit(&stats->serviced); ++ blkg_rwstat_exit(&stats->merged); ++ blkg_rwstat_exit(&stats->service_time); ++ blkg_rwstat_exit(&stats->wait_time); ++ blkg_rwstat_exit(&stats->queued); ++ blkg_stat_exit(&stats->sectors); ++ blkg_stat_exit(&stats->time); ++ blkg_stat_exit(&stats->unaccounted_time); ++ blkg_stat_exit(&stats->avg_queue_size_sum); ++ blkg_stat_exit(&stats->avg_queue_size_samples); ++ blkg_stat_exit(&stats->dequeue); ++ blkg_stat_exit(&stats->group_wait_time); ++ blkg_stat_exit(&stats->idle_time); ++ blkg_stat_exit(&stats->empty_time); ++} ++ ++static int bfqg_stats_init(struct bfqg_stats *stats, gfp_t gfp) ++{ ++ if (blkg_rwstat_init(&stats->service_bytes, gfp) || ++ blkg_rwstat_init(&stats->serviced, gfp) || ++ blkg_rwstat_init(&stats->merged, gfp) || ++ blkg_rwstat_init(&stats->service_time, gfp) || ++ blkg_rwstat_init(&stats->wait_time, gfp) || ++ blkg_rwstat_init(&stats->queued, gfp) || ++ blkg_stat_init(&stats->sectors, gfp) || ++ blkg_stat_init(&stats->time, gfp) || ++ blkg_stat_init(&stats->unaccounted_time, gfp) || ++ blkg_stat_init(&stats->avg_queue_size_sum, gfp) || ++ blkg_stat_init(&stats->avg_queue_size_samples, gfp) || ++ blkg_stat_init(&stats->dequeue, gfp) || ++ blkg_stat_init(&stats->group_wait_time, gfp) || ++ blkg_stat_init(&stats->idle_time, gfp) || ++ blkg_stat_init(&stats->empty_time, gfp)) { ++ bfqg_stats_exit(stats); ++ return -ENOMEM; ++ } ++ ++ return 0; ++} ++ ++static struct bfq_group_data *cpd_to_bfqgd(struct blkcg_policy_data *cpd) ++ { ++ return cpd ? container_of(cpd, struct bfq_group_data, pd) : NULL; ++ } ++ ++static struct bfq_group_data *blkcg_to_bfqgd(struct blkcg *blkcg) ++{ ++ return cpd_to_bfqgd(blkcg_to_cpd(blkcg, &blkcg_policy_bfq)); ++} ++ ++static void bfq_cpd_init(struct blkcg_policy_data *cpd) ++{ ++ struct bfq_group_data *d = cpd_to_bfqgd(cpd); ++ ++ d->weight = BFQ_DEFAULT_GRP_WEIGHT; ++} ++ ++static struct blkg_policy_data *bfq_pd_alloc(gfp_t gfp, int node) ++{ ++ struct bfq_group *bfqg; ++ ++ bfqg = kzalloc_node(sizeof(*bfqg), gfp, node); ++ if (!bfqg) ++ return NULL; ++ ++ if (bfqg_stats_init(&bfqg->stats, gfp)) { ++ kfree(bfqg); ++ return NULL; ++ } ++ ++ return &bfqg->pd; ++} ++ ++static void bfq_pd_init(struct blkg_policy_data *pd) ++{ ++ struct blkcg_gq *blkg = pd_to_blkg(pd); ++ struct bfq_group *bfqg = blkg_to_bfqg(blkg); ++ struct bfq_data *bfqd = blkg->q->elevator->elevator_data; ++ struct bfq_entity *entity = &bfqg->entity; ++ struct bfq_group_data *d = blkcg_to_bfqgd(blkg->blkcg); ++ ++ entity->orig_weight = entity->weight = entity->new_weight = d->weight; ++ entity->my_sched_data = &bfqg->sched_data; ++ bfqg->my_entity = entity; /* ++ * the root_group's will be set to NULL ++ * in bfq_init_queue() ++ */ ++ bfqg->bfqd = bfqd; ++ bfqg->active_entities = 0; ++ ++ /* if the root_group does not exist, we are handling it right now */ ++ if (bfqd->root_group && bfqg != bfqd->root_group) ++ hlist_add_head(&bfqg->bfqd_node, &bfqd->group_list); ++} ++ ++static void bfq_pd_free(struct blkg_policy_data *pd) ++{ ++ return kfree(pd_to_bfqg(pd)); ++} ++ ++/* offset delta from bfqg->stats to bfqg->dead_stats */ ++static const int dead_stats_off_delta = offsetof(struct bfq_group, dead_stats) - ++ offsetof(struct bfq_group, stats); ++ ++/* to be used by recursive prfill, sums live and dead stats recursively */ ++static u64 bfqg_stat_pd_recursive_sum(struct blkg_policy_data *pd, int off) ++{ ++ u64 sum = 0; ++ ++ sum += blkg_stat_recursive_sum(pd_to_blkg(pd), &blkcg_policy_bfq, off); ++ sum += blkg_stat_recursive_sum(pd_to_blkg(pd), &blkcg_policy_bfq, ++ off + dead_stats_off_delta); ++ return sum; ++} ++ ++/* to be used by recursive prfill, sums live and dead rwstats recursively */ ++static struct blkg_rwstat bfqg_rwstat_pd_recursive_sum(struct blkg_policy_data *pd, ++ int off) ++{ ++ struct blkg_rwstat a, b; ++ ++ a = blkg_rwstat_recursive_sum(pd_to_blkg(pd), &blkcg_policy_bfq, off); ++ b = blkg_rwstat_recursive_sum(pd_to_blkg(pd), &blkcg_policy_bfq, ++ off + dead_stats_off_delta); ++ blkg_rwstat_add_aux(&a, &b); ++ return a; ++} ++ ++static void bfq_pd_reset_stats(struct blkg_policy_data *pd) ++{ ++ struct bfq_group *bfqg = pd_to_bfqg(pd); ++ ++ bfqg_stats_reset(&bfqg->stats); ++ bfqg_stats_reset(&bfqg->dead_stats); ++} ++ ++static void bfq_group_set_parent(struct bfq_group *bfqg, ++ struct bfq_group *parent) ++{ ++ struct bfq_entity *entity; ++ ++ BUG_ON(!parent); ++ BUG_ON(!bfqg); ++ BUG_ON(bfqg == parent); ++ ++ entity = &bfqg->entity; ++ entity->parent = parent->my_entity; ++ entity->sched_data = &parent->sched_data; ++} ++ ++static struct bfq_group *bfq_find_alloc_group(struct bfq_data *bfqd, ++ struct blkcg *blkcg) ++{ ++ struct request_queue *q = bfqd->queue; ++ struct bfq_group *bfqg = NULL, *parent; ++ struct bfq_entity *entity = NULL; ++ ++ assert_spin_locked(bfqd->queue->queue_lock); ++ ++ /* avoid lookup for the common case where there's no blkcg */ ++ if (blkcg == &blkcg_root) { ++ bfqg = bfqd->root_group; ++ } else { ++ struct blkcg_gq *blkg; ++ ++ blkg = blkg_lookup_create(blkcg, q); ++ if (!IS_ERR(blkg)) ++ bfqg = blkg_to_bfqg(blkg); ++ else /* fallback to root_group */ ++ bfqg = bfqd->root_group; ++ } ++ ++ BUG_ON(!bfqg); ++ ++ /* ++ * Update chain of bfq_groups as we might be handling a leaf group ++ * which, along with some of its relatives, has not been hooked yet ++ * to the private hierarchy of BFQ. ++ */ ++ entity = &bfqg->entity; ++ for_each_entity(entity) { ++ bfqg = container_of(entity, struct bfq_group, entity); ++ BUG_ON(!bfqg); ++ if (bfqg != bfqd->root_group) { ++ parent = bfqg_parent(bfqg); ++ if (!parent) ++ parent = bfqd->root_group; ++ BUG_ON(!parent); ++ bfq_group_set_parent(bfqg, parent); ++ } ++ } ++ ++ return bfqg; ++} ++ ++/** ++ * bfq_bfqq_move - migrate @bfqq to @bfqg. ++ * @bfqd: queue descriptor. ++ * @bfqq: the queue to move. ++ * @entity: @bfqq's entity. ++ * @bfqg: the group to move to. ++ * ++ * Move @bfqq to @bfqg, deactivating it from its old group and reactivating ++ * it on the new one. Avoid putting the entity on the old group idle tree. ++ * ++ * Must be called under the queue lock; the cgroup owning @bfqg must ++ * not disappear (by now this just means that we are called under ++ * rcu_read_lock()). ++ */ ++static void bfq_bfqq_move(struct bfq_data *bfqd, struct bfq_queue *bfqq, ++ struct bfq_entity *entity, struct bfq_group *bfqg) ++{ ++ int busy, resume; ++ ++ busy = bfq_bfqq_busy(bfqq); ++ resume = !RB_EMPTY_ROOT(&bfqq->sort_list); ++ ++ BUG_ON(resume && !entity->on_st); ++ BUG_ON(busy && !resume && entity->on_st && ++ bfqq != bfqd->in_service_queue); ++ ++ if (busy) { ++ BUG_ON(atomic_read(&bfqq->ref) < 2); ++ ++ if (!resume) ++ bfq_del_bfqq_busy(bfqd, bfqq, 0); ++ else ++ bfq_deactivate_bfqq(bfqd, bfqq, 0); ++ } else if (entity->on_st) ++ bfq_put_idle_entity(bfq_entity_service_tree(entity), entity); ++ bfqg_put(bfqq_group(bfqq)); ++ ++ /* ++ * Here we use a reference to bfqg. We don't need a refcounter ++ * as the cgroup reference will not be dropped, so that its ++ * destroy() callback will not be invoked. ++ */ ++ entity->parent = bfqg->my_entity; ++ entity->sched_data = &bfqg->sched_data; ++ bfqg_get(bfqg); ++ ++ if (busy) { ++ if (resume) ++ bfq_activate_bfqq(bfqd, bfqq); ++ } ++ ++ if (!bfqd->in_service_queue && !bfqd->rq_in_driver) ++ bfq_schedule_dispatch(bfqd); ++} ++ ++/** ++ * __bfq_bic_change_cgroup - move @bic to @cgroup. ++ * @bfqd: the queue descriptor. ++ * @bic: the bic to move. ++ * @blkcg: the blk-cgroup to move to. ++ * ++ * Move bic to blkcg, assuming that bfqd->queue is locked; the caller ++ * has to make sure that the reference to cgroup is valid across the call. ++ * ++ * NOTE: an alternative approach might have been to store the current ++ * cgroup in bfqq and getting a reference to it, reducing the lookup ++ * time here, at the price of slightly more complex code. ++ */ ++static struct bfq_group *__bfq_bic_change_cgroup(struct bfq_data *bfqd, ++ struct bfq_io_cq *bic, ++ struct blkcg *blkcg) ++{ ++ struct bfq_queue *async_bfqq = bic_to_bfqq(bic, 0); ++ struct bfq_queue *sync_bfqq = bic_to_bfqq(bic, 1); ++ struct bfq_group *bfqg; ++ struct bfq_entity *entity; ++ ++ lockdep_assert_held(bfqd->queue->queue_lock); ++ ++ bfqg = bfq_find_alloc_group(bfqd, blkcg); ++ if (async_bfqq) { ++ entity = &async_bfqq->entity; ++ ++ if (entity->sched_data != &bfqg->sched_data) { ++ bic_set_bfqq(bic, NULL, 0); ++ bfq_log_bfqq(bfqd, async_bfqq, ++ "bic_change_group: %p %d", ++ async_bfqq, atomic_read(&async_bfqq->ref)); ++ bfq_put_queue(async_bfqq); ++ } ++ } ++ ++ if (sync_bfqq) { ++ entity = &sync_bfqq->entity; ++ if (entity->sched_data != &bfqg->sched_data) ++ bfq_bfqq_move(bfqd, sync_bfqq, entity, bfqg); ++ } ++ ++ return bfqg; ++} ++ ++static void bfq_bic_update_cgroup(struct bfq_io_cq *bic, struct bio *bio) ++{ ++ struct bfq_data *bfqd = bic_to_bfqd(bic); ++ struct blkcg *blkcg; ++ struct bfq_group *bfqg = NULL; ++ uint64_t id; ++ ++ rcu_read_lock(); ++ blkcg = bio_blkcg(bio); ++ id = blkcg->css.serial_nr; ++ rcu_read_unlock(); ++ ++ /* ++ * Check whether blkcg has changed. The condition may trigger ++ * spuriously on a newly created cic but there's no harm. ++ */ ++ if (unlikely(!bfqd) || likely(bic->blkcg_id == id)) ++ return; ++ ++ bfqg = __bfq_bic_change_cgroup(bfqd, bic, blkcg); ++ BUG_ON(!bfqg); ++ bic->blkcg_id = id; ++} ++ ++/** ++ * bfq_flush_idle_tree - deactivate any entity on the idle tree of @st. ++ * @st: the service tree being flushed. ++ */ ++static void bfq_flush_idle_tree(struct bfq_service_tree *st) ++{ ++ struct bfq_entity *entity = st->first_idle; ++ ++ for (; entity ; entity = st->first_idle) ++ __bfq_deactivate_entity(entity, 0); ++} ++ ++/** ++ * bfq_reparent_leaf_entity - move leaf entity to the root_group. ++ * @bfqd: the device data structure with the root group. ++ * @entity: the entity to move. ++ */ ++static void bfq_reparent_leaf_entity(struct bfq_data *bfqd, ++ struct bfq_entity *entity) ++{ ++ struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); ++ ++ BUG_ON(!bfqq); ++ bfq_bfqq_move(bfqd, bfqq, entity, bfqd->root_group); ++ return; ++} ++ ++/** ++ * bfq_reparent_active_entities - move to the root group all active ++ * entities. ++ * @bfqd: the device data structure with the root group. ++ * @bfqg: the group to move from. ++ * @st: the service tree with the entities. ++ * ++ * Needs queue_lock to be taken and reference to be valid over the call. ++ */ ++static void bfq_reparent_active_entities(struct bfq_data *bfqd, ++ struct bfq_group *bfqg, ++ struct bfq_service_tree *st) ++{ ++ struct rb_root *active = &st->active; ++ struct bfq_entity *entity = NULL; ++ ++ if (!RB_EMPTY_ROOT(&st->active)) ++ entity = bfq_entity_of(rb_first(active)); ++ ++ for (; entity ; entity = bfq_entity_of(rb_first(active))) ++ bfq_reparent_leaf_entity(bfqd, entity); ++ ++ if (bfqg->sched_data.in_service_entity) ++ bfq_reparent_leaf_entity(bfqd, ++ bfqg->sched_data.in_service_entity); ++ ++ return; ++} ++ ++/** ++ * bfq_destroy_group - destroy @bfqg. ++ * @bfqg: the group being destroyed. ++ * ++ * Destroy @bfqg, making sure that it is not referenced from its parent. ++ * blkio already grabs the queue_lock for us, so no need to use RCU-based magic ++ */ ++static void bfq_pd_offline(struct blkg_policy_data *pd) ++{ ++ struct bfq_service_tree *st; ++ struct bfq_group *bfqg = pd_to_bfqg(pd); ++ struct bfq_data *bfqd = bfqg->bfqd; ++ struct bfq_entity *entity = bfqg->my_entity; ++ int i; ++ ++ if (!entity) /* root group */ ++ return; ++ ++ /* ++ * Empty all service_trees belonging to this group before ++ * deactivating the group itself. ++ */ ++ for (i = 0; i < BFQ_IOPRIO_CLASSES; i++) { ++ st = bfqg->sched_data.service_tree + i; ++ ++ /* ++ * The idle tree may still contain bfq_queues belonging ++ * to exited task because they never migrated to a different ++ * cgroup from the one being destroyed now. No one else ++ * can access them so it's safe to act without any lock. ++ */ ++ bfq_flush_idle_tree(st); ++ ++ /* ++ * It may happen that some queues are still active ++ * (busy) upon group destruction (if the corresponding ++ * processes have been forced to terminate). We move ++ * all the leaf entities corresponding to these queues ++ * to the root_group. ++ * Also, it may happen that the group has an entity ++ * in service, which is disconnected from the active ++ * tree: it must be moved, too. ++ * There is no need to put the sync queues, as the ++ * scheduler has taken no reference. ++ */ ++ bfq_reparent_active_entities(bfqd, bfqg, st); ++ BUG_ON(!RB_EMPTY_ROOT(&st->active)); ++ BUG_ON(!RB_EMPTY_ROOT(&st->idle)); ++ } ++ BUG_ON(bfqg->sched_data.next_in_service); ++ BUG_ON(bfqg->sched_data.in_service_entity); ++ ++ hlist_del(&bfqg->bfqd_node); ++ __bfq_deactivate_entity(entity, 0); ++ bfq_put_async_queues(bfqd, bfqg); ++ BUG_ON(entity->tree); ++ ++ bfqg_stats_xfer_dead(bfqg); ++} ++ ++static void bfq_end_wr_async(struct bfq_data *bfqd) ++{ ++ struct hlist_node *tmp; ++ struct bfq_group *bfqg; ++ ++ hlist_for_each_entry_safe(bfqg, tmp, &bfqd->group_list, bfqd_node) ++ bfq_end_wr_async_queues(bfqd, bfqg); ++ bfq_end_wr_async_queues(bfqd, bfqd->root_group); ++} ++ ++/** ++ * bfq_disconnect_groups - disconnect @bfqd from all its groups. ++ * @bfqd: the device descriptor being exited. ++ * ++ * When the device exits we just make sure that no lookup can return ++ * the now unused group structures. They will be deallocated on cgroup ++ * destruction. ++ */ ++static void bfq_disconnect_groups(struct bfq_data *bfqd) ++{ ++ struct hlist_node *tmp; ++ struct bfq_group *bfqg; ++ ++ bfq_log(bfqd, "disconnect_groups beginning"); ++ hlist_for_each_entry_safe(bfqg, tmp, &bfqd->group_list, bfqd_node) { ++ hlist_del(&bfqg->bfqd_node); ++ ++ __bfq_deactivate_entity(bfqg->my_entity, 0); ++ ++ /* ++ * Don't remove from the group hash, just set an ++ * invalid key. No lookups can race with the ++ * assignment as bfqd is being destroyed; this ++ * implies also that new elements cannot be added ++ * to the list. ++ */ ++ rcu_assign_pointer(bfqg->bfqd, NULL); ++ ++ bfq_log(bfqd, "disconnect_groups: put async for group %p", ++ bfqg); ++ bfq_put_async_queues(bfqd, bfqg); ++ } ++} ++ ++static u64 bfqio_cgroup_weight_read(struct cgroup_subsys_state *css, ++ struct cftype *cftype) ++{ ++ struct blkcg *blkcg = css_to_blkcg(css); ++ struct bfq_group_data *bfqgd = blkcg_to_bfqgd(blkcg); ++ int ret = -EINVAL; ++ ++ spin_lock_irq(&blkcg->lock); ++ ret = bfqgd->weight; ++ spin_unlock_irq(&blkcg->lock); ++ ++ return ret; ++} ++ ++static int bfqio_cgroup_weight_read_dfl(struct seq_file *sf, void *v) ++{ ++ struct blkcg *blkcg = css_to_blkcg(seq_css(sf)); ++ struct bfq_group_data *bfqgd = blkcg_to_bfqgd(blkcg); ++ ++ spin_lock_irq(&blkcg->lock); ++ seq_printf(sf, "%u\n", bfqgd->weight); ++ spin_unlock_irq(&blkcg->lock); ++ ++ return 0; ++} ++ ++static int bfqio_cgroup_weight_write(struct cgroup_subsys_state *css, ++ struct cftype *cftype, ++ u64 val) ++{ ++ struct blkcg *blkcg = css_to_blkcg(css); ++ struct bfq_group_data *bfqgd = blkcg_to_bfqgd(blkcg); ++ struct blkcg_gq *blkg; ++ int ret = -EINVAL; ++ ++ if (val < BFQ_MIN_WEIGHT || val > BFQ_MAX_WEIGHT) ++ return ret; ++ ++ ret = 0; ++ spin_lock_irq(&blkcg->lock); ++ bfqgd->weight = (unsigned short)val; ++ hlist_for_each_entry(blkg, &blkcg->blkg_list, blkcg_node) { ++ struct bfq_group *bfqg = blkg_to_bfqg(blkg); ++ if (!bfqg) ++ continue; ++ /* ++ * Setting the prio_changed flag of the entity ++ * to 1 with new_weight == weight would re-set ++ * the value of the weight to its ioprio mapping. ++ * Set the flag only if necessary. ++ */ ++ if ((unsigned short)val != bfqg->entity.new_weight) { ++ bfqg->entity.new_weight = (unsigned short)val; ++ /* ++ * Make sure that the above new value has been ++ * stored in bfqg->entity.new_weight before ++ * setting the prio_changed flag. In fact, ++ * this flag may be read asynchronously (in ++ * critical sections protected by a different ++ * lock than that held here), and finding this ++ * flag set may cause the execution of the code ++ * for updating parameters whose value may ++ * depend also on bfqg->entity.new_weight (in ++ * __bfq_entity_update_weight_prio). ++ * This barrier makes sure that the new value ++ * of bfqg->entity.new_weight is correctly ++ * seen in that code. ++ */ ++ smp_wmb(); ++ bfqg->entity.prio_changed = 1; ++ } ++ } ++ spin_unlock_irq(&blkcg->lock); ++ ++ return ret; ++} ++ ++static ssize_t bfqio_cgroup_weight_write_dfl(struct kernfs_open_file *of, ++ char *buf, size_t nbytes, ++ loff_t off) ++{ ++ /* First unsigned long found in the file is used */ ++ return bfqio_cgroup_weight_write(of_css(of), NULL, ++ simple_strtoull(strim(buf), NULL, 0)); ++} ++ ++static int bfqg_print_stat(struct seq_file *sf, void *v) ++{ ++ blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), blkg_prfill_stat, ++ &blkcg_policy_bfq, seq_cft(sf)->private, false); ++ return 0; ++} ++ ++static int bfqg_print_rwstat(struct seq_file *sf, void *v) ++{ ++ blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), blkg_prfill_rwstat, ++ &blkcg_policy_bfq, seq_cft(sf)->private, true); ++ return 0; ++} ++ ++static u64 bfqg_prfill_stat_recursive(struct seq_file *sf, ++ struct blkg_policy_data *pd, int off) ++{ ++ u64 sum = bfqg_stat_pd_recursive_sum(pd, off); ++ ++ return __blkg_prfill_u64(sf, pd, sum); ++} ++ ++static u64 bfqg_prfill_rwstat_recursive(struct seq_file *sf, ++ struct blkg_policy_data *pd, int off) ++{ ++ struct blkg_rwstat sum = bfqg_rwstat_pd_recursive_sum(pd, off); ++ ++ return __blkg_prfill_rwstat(sf, pd, &sum); ++} ++ ++static int bfqg_print_stat_recursive(struct seq_file *sf, void *v) ++{ ++ blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), ++ bfqg_prfill_stat_recursive, &blkcg_policy_bfq, ++ seq_cft(sf)->private, false); ++ return 0; ++} ++ ++static int bfqg_print_rwstat_recursive(struct seq_file *sf, void *v) ++{ ++ blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), ++ bfqg_prfill_rwstat_recursive, &blkcg_policy_bfq, ++ seq_cft(sf)->private, true); ++ return 0; ++} ++ ++static u64 bfqg_prfill_avg_queue_size(struct seq_file *sf, ++ struct blkg_policy_data *pd, int off) ++{ ++ struct bfq_group *bfqg = pd_to_bfqg(pd); ++ u64 samples = blkg_stat_read(&bfqg->stats.avg_queue_size_samples); ++ u64 v = 0; ++ ++ if (samples) { ++ v = blkg_stat_read(&bfqg->stats.avg_queue_size_sum); ++ v = div64_u64(v, samples); ++ } ++ __blkg_prfill_u64(sf, pd, v); ++ return 0; ++} ++ ++/* print avg_queue_size */ ++static int bfqg_print_avg_queue_size(struct seq_file *sf, void *v) ++{ ++ blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), ++ bfqg_prfill_avg_queue_size, &blkcg_policy_bfq, ++ 0, false); ++ return 0; ++} ++ ++static struct bfq_group *bfq_create_group_hierarchy(struct bfq_data *bfqd, int node) ++{ ++ int ret; ++ ++ ret = blkcg_activate_policy(bfqd->queue, &blkcg_policy_bfq); ++ if (ret) ++ return NULL; ++ ++ return blkg_to_bfqg(bfqd->queue->root_blkg); ++} ++ ++static struct blkcg_policy_data *bfq_cpd_alloc(gfp_t gfp) ++{ ++ struct bfq_group_data *bgd; ++ ++ bgd = kzalloc(sizeof(*bgd), GFP_KERNEL); ++ if (!bgd) ++ return NULL; ++ return &bgd->pd; ++} ++ ++static void bfq_cpd_free(struct blkcg_policy_data *cpd) ++{ ++ kfree(cpd_to_bfqgd(cpd)); ++} ++ ++static struct cftype bfqio_files_dfl[] = { ++ { ++ .name = "weight", ++ .flags = CFTYPE_NOT_ON_ROOT, ++ .seq_show = bfqio_cgroup_weight_read_dfl, ++ .write = bfqio_cgroup_weight_write_dfl, ++ }, ++ {} /* terminate */ ++}; ++ ++static struct cftype bfqio_files[] = { ++ { ++ .name = "bfq.weight", ++ .read_u64 = bfqio_cgroup_weight_read, ++ .write_u64 = bfqio_cgroup_weight_write, ++ }, ++ /* statistics, cover only the tasks in the bfqg */ ++ { ++ .name = "bfq.time", ++ .private = offsetof(struct bfq_group, stats.time), ++ .seq_show = bfqg_print_stat, ++ }, ++ { ++ .name = "bfq.sectors", ++ .private = offsetof(struct bfq_group, stats.sectors), ++ .seq_show = bfqg_print_stat, ++ }, ++ { ++ .name = "bfq.io_service_bytes", ++ .private = offsetof(struct bfq_group, stats.service_bytes), ++ .seq_show = bfqg_print_rwstat, ++ }, ++ { ++ .name = "bfq.io_serviced", ++ .private = offsetof(struct bfq_group, stats.serviced), ++ .seq_show = bfqg_print_rwstat, ++ }, ++ { ++ .name = "bfq.io_service_time", ++ .private = offsetof(struct bfq_group, stats.service_time), ++ .seq_show = bfqg_print_rwstat, ++ }, ++ { ++ .name = "bfq.io_wait_time", ++ .private = offsetof(struct bfq_group, stats.wait_time), ++ .seq_show = bfqg_print_rwstat, ++ }, ++ { ++ .name = "bfq.io_merged", ++ .private = offsetof(struct bfq_group, stats.merged), ++ .seq_show = bfqg_print_rwstat, ++ }, ++ { ++ .name = "bfq.io_queued", ++ .private = offsetof(struct bfq_group, stats.queued), ++ .seq_show = bfqg_print_rwstat, ++ }, ++ ++ /* the same statictics which cover the bfqg and its descendants */ ++ { ++ .name = "bfq.time_recursive", ++ .private = offsetof(struct bfq_group, stats.time), ++ .seq_show = bfqg_print_stat_recursive, ++ }, ++ { ++ .name = "bfq.sectors_recursive", ++ .private = offsetof(struct bfq_group, stats.sectors), ++ .seq_show = bfqg_print_stat_recursive, ++ }, ++ { ++ .name = "bfq.io_service_bytes_recursive", ++ .private = offsetof(struct bfq_group, stats.service_bytes), ++ .seq_show = bfqg_print_rwstat_recursive, ++ }, ++ { ++ .name = "bfq.io_serviced_recursive", ++ .private = offsetof(struct bfq_group, stats.serviced), ++ .seq_show = bfqg_print_rwstat_recursive, ++ }, ++ { ++ .name = "bfq.io_service_time_recursive", ++ .private = offsetof(struct bfq_group, stats.service_time), ++ .seq_show = bfqg_print_rwstat_recursive, ++ }, ++ { ++ .name = "bfq.io_wait_time_recursive", ++ .private = offsetof(struct bfq_group, stats.wait_time), ++ .seq_show = bfqg_print_rwstat_recursive, ++ }, ++ { ++ .name = "bfq.io_merged_recursive", ++ .private = offsetof(struct bfq_group, stats.merged), ++ .seq_show = bfqg_print_rwstat_recursive, ++ }, ++ { ++ .name = "bfq.io_queued_recursive", ++ .private = offsetof(struct bfq_group, stats.queued), ++ .seq_show = bfqg_print_rwstat_recursive, ++ }, ++ { ++ .name = "bfq.avg_queue_size", ++ .seq_show = bfqg_print_avg_queue_size, ++ }, ++ { ++ .name = "bfq.group_wait_time", ++ .private = offsetof(struct bfq_group, stats.group_wait_time), ++ .seq_show = bfqg_print_stat, ++ }, ++ { ++ .name = "bfq.idle_time", ++ .private = offsetof(struct bfq_group, stats.idle_time), ++ .seq_show = bfqg_print_stat, ++ }, ++ { ++ .name = "bfq.empty_time", ++ .private = offsetof(struct bfq_group, stats.empty_time), ++ .seq_show = bfqg_print_stat, ++ }, ++ { ++ .name = "bfq.dequeue", ++ .private = offsetof(struct bfq_group, stats.dequeue), ++ .seq_show = bfqg_print_stat, ++ }, ++ { ++ .name = "bfq.unaccounted_time", ++ .private = offsetof(struct bfq_group, stats.unaccounted_time), ++ .seq_show = bfqg_print_stat, ++ }, ++ { } /* terminate */ ++}; ++ ++static struct blkcg_policy blkcg_policy_bfq = { ++ .dfl_cftypes = bfqio_files_dfl, ++ .legacy_cftypes = bfqio_files, ++ ++ .pd_alloc_fn = bfq_pd_alloc, ++ .pd_init_fn = bfq_pd_init, ++ .pd_offline_fn = bfq_pd_offline, ++ .pd_free_fn = bfq_pd_free, ++ .pd_reset_stats_fn = bfq_pd_reset_stats, ++ ++ .cpd_alloc_fn = bfq_cpd_alloc, ++ .cpd_init_fn = bfq_cpd_init, ++ .cpd_bind_fn = bfq_cpd_init, ++ .cpd_free_fn = bfq_cpd_free, ++ ++}; ++ ++#else ++ ++static void bfq_init_entity(struct bfq_entity *entity, ++ struct bfq_group *bfqg) ++{ ++ struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); ++ entity->weight = entity->new_weight; ++ entity->orig_weight = entity->new_weight; ++ if (bfqq) { ++ bfqq->ioprio = bfqq->new_ioprio; ++ bfqq->ioprio_class = bfqq->new_ioprio_class; ++ } ++ entity->sched_data = &bfqg->sched_data; ++} ++ ++static struct bfq_group * ++bfq_bic_update_cgroup(struct bfq_io_cq *bic, struct bio *bio) ++{ ++ struct bfq_data *bfqd = bic_to_bfqd(bic); ++ return bfqd->root_group; ++} ++ ++static void bfq_bfqq_move(struct bfq_data *bfqd, ++ struct bfq_queue *bfqq, ++ struct bfq_entity *entity, ++ struct bfq_group *bfqg) ++{ ++} ++ ++static void bfq_end_wr_async(struct bfq_data *bfqd) ++{ ++ bfq_end_wr_async_queues(bfqd, bfqd->root_group); ++} ++ ++static void bfq_disconnect_groups(struct bfq_data *bfqd) ++{ ++ bfq_put_async_queues(bfqd, bfqd->root_group); ++} ++ ++static struct bfq_group *bfq_find_alloc_group(struct bfq_data *bfqd, ++ struct blkcg *blkcg) ++{ ++ return bfqd->root_group; ++} ++ ++static struct bfq_group *bfq_create_group_hierarchy(struct bfq_data *bfqd, int node) ++{ ++ struct bfq_group *bfqg; ++ int i; ++ ++ bfqg = kmalloc_node(sizeof(*bfqg), GFP_KERNEL | __GFP_ZERO, node); ++ if (!bfqg) ++ return NULL; ++ ++ for (i = 0; i < BFQ_IOPRIO_CLASSES; i++) ++ bfqg->sched_data.service_tree[i] = BFQ_SERVICE_TREE_INIT; ++ ++ return bfqg; ++} ++#endif +diff --git a/block/bfq-ioc.c b/block/bfq-ioc.c +new file mode 100644 +index 0000000..fb7bb8f +--- /dev/null ++++ b/block/bfq-ioc.c +@@ -0,0 +1,36 @@ ++/* ++ * BFQ: I/O context handling. ++ * ++ * Based on ideas and code from CFQ: ++ * Copyright (C) 2003 Jens Axboe ++ * ++ * Copyright (C) 2008 Fabio Checconi ++ * Paolo Valente ++ * ++ * Copyright (C) 2010 Paolo Valente ++ */ ++ ++/** ++ * icq_to_bic - convert iocontext queue structure to bfq_io_cq. ++ * @icq: the iocontext queue. ++ */ ++static struct bfq_io_cq *icq_to_bic(struct io_cq *icq) ++{ ++ /* bic->icq is the first member, %NULL will convert to %NULL */ ++ return container_of(icq, struct bfq_io_cq, icq); ++} ++ ++/** ++ * bfq_bic_lookup - search into @ioc a bic associated to @bfqd. ++ * @bfqd: the lookup key. ++ * @ioc: the io_context of the process doing I/O. ++ * ++ * Queue lock must be held. ++ */ ++static struct bfq_io_cq *bfq_bic_lookup(struct bfq_data *bfqd, ++ struct io_context *ioc) ++{ ++ if (ioc) ++ return icq_to_bic(ioc_lookup_icq(ioc, bfqd->queue)); ++ return NULL; ++} +diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c +new file mode 100644 +index 0000000..d61e402 +--- /dev/null ++++ b/block/bfq-iosched.c +@@ -0,0 +1,3753 @@ ++/* ++ * Budget Fair Queueing (BFQ) disk scheduler. ++ * ++ * Based on ideas and code from CFQ: ++ * Copyright (C) 2003 Jens Axboe ++ * ++ * Copyright (C) 2008 Fabio Checconi ++ * Paolo Valente ++ * ++ * Copyright (C) 2010 Paolo Valente ++ * ++ * Licensed under the GPL-2 as detailed in the accompanying COPYING.BFQ ++ * file. ++ * ++ * BFQ is a proportional-share storage-I/O scheduling algorithm based on ++ * the slice-by-slice service scheme of CFQ. But BFQ assigns budgets, ++ * measured in number of sectors, to processes instead of time slices. The ++ * device is not granted to the in-service process for a given time slice, ++ * but until it has exhausted its assigned budget. This change from the time ++ * to the service domain allows BFQ to distribute the device throughput ++ * among processes as desired, without any distortion due to ZBR, workload ++ * fluctuations or other factors. BFQ uses an ad hoc internal scheduler, ++ * called B-WF2Q+, to schedule processes according to their budgets. More ++ * precisely, BFQ schedules queues associated to processes. Thanks to the ++ * accurate policy of B-WF2Q+, BFQ can afford to assign high budgets to ++ * I/O-bound processes issuing sequential requests (to boost the ++ * throughput), and yet guarantee a low latency to interactive and soft ++ * real-time applications. ++ * ++ * BFQ is described in [1], where also a reference to the initial, more ++ * theoretical paper on BFQ can be found. The interested reader can find ++ * in the latter paper full details on the main algorithm, as well as ++ * formulas of the guarantees and formal proofs of all the properties. ++ * With respect to the version of BFQ presented in these papers, this ++ * implementation adds a few more heuristics, such as the one that ++ * guarantees a low latency to soft real-time applications, and a ++ * hierarchical extension based on H-WF2Q+. ++ * ++ * B-WF2Q+ is based on WF2Q+, that is described in [2], together with ++ * H-WF2Q+, while the augmented tree used to implement B-WF2Q+ with O(log N) ++ * complexity derives from the one introduced with EEVDF in [3]. ++ * ++ * [1] P. Valente and M. Andreolini, ``Improving Application Responsiveness ++ * with the BFQ Disk I/O Scheduler'', ++ * Proceedings of the 5th Annual International Systems and Storage ++ * Conference (SYSTOR '12), June 2012. ++ * ++ * http://algogroup.unimo.it/people/paolo/disk_sched/bf1-v1-suite-results.pdf ++ * ++ * [2] Jon C.R. Bennett and H. Zhang, ``Hierarchical Packet Fair Queueing ++ * Algorithms,'' IEEE/ACM Transactions on Networking, 5(5):675-689, ++ * Oct 1997. ++ * ++ * http://www.cs.cmu.edu/~hzhang/papers/TON-97-Oct.ps.gz ++ * ++ * [3] I. Stoica and H. Abdel-Wahab, ``Earliest Eligible Virtual Deadline ++ * First: A Flexible and Accurate Mechanism for Proportional Share ++ * Resource Allocation,'' technical report. ++ * ++ * http://www.cs.berkeley.edu/~istoica/papers/eevdf-tr-95.pdf ++ */ ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include "bfq.h" ++#include "blk.h" ++ ++/* Expiration time of sync (0) and async (1) requests, in jiffies. */ ++static const int bfq_fifo_expire[2] = { HZ / 4, HZ / 8 }; ++ ++/* Maximum backwards seek, in KiB. */ ++static const int bfq_back_max = 16 * 1024; ++ ++/* Penalty of a backwards seek, in number of sectors. */ ++static const int bfq_back_penalty = 2; ++ ++/* Idling period duration, in jiffies. */ ++static int bfq_slice_idle = HZ / 125; ++ ++/* Minimum number of assigned budgets for which stats are safe to compute. */ ++static const int bfq_stats_min_budgets = 194; ++ ++/* Default maximum budget values, in sectors and number of requests. */ ++static const int bfq_default_max_budget = 16 * 1024; ++static const int bfq_max_budget_async_rq = 4; ++ ++/* ++ * Async to sync throughput distribution is controlled as follows: ++ * when an async request is served, the entity is charged the number ++ * of sectors of the request, multiplied by the factor below ++ */ ++static const int bfq_async_charge_factor = 10; ++ ++/* Default timeout values, in jiffies, approximating CFQ defaults. */ ++static const int bfq_timeout_sync = HZ / 8; ++static int bfq_timeout_async = HZ / 25; ++ ++struct kmem_cache *bfq_pool; ++ ++/* Below this threshold (in ms), we consider thinktime immediate. */ ++#define BFQ_MIN_TT 2 ++ ++/* hw_tag detection: parallel requests threshold and min samples needed. */ ++#define BFQ_HW_QUEUE_THRESHOLD 4 ++#define BFQ_HW_QUEUE_SAMPLES 32 ++ ++#define BFQQ_SEEK_THR (sector_t)(8 * 1024) ++#define BFQQ_SEEKY(bfqq) ((bfqq)->seek_mean > BFQQ_SEEK_THR) ++ ++/* Min samples used for peak rate estimation (for autotuning). */ ++#define BFQ_PEAK_RATE_SAMPLES 32 ++ ++/* Shift used for peak rate fixed precision calculations. */ ++#define BFQ_RATE_SHIFT 16 ++ ++/* ++ * By default, BFQ computes the duration of the weight raising for ++ * interactive applications automatically, using the following formula: ++ * duration = (R / r) * T, where r is the peak rate of the device, and ++ * R and T are two reference parameters. ++ * In particular, R is the peak rate of the reference device (see below), ++ * and T is a reference time: given the systems that are likely to be ++ * installed on the reference device according to its speed class, T is ++ * about the maximum time needed, under BFQ and while reading two files in ++ * parallel, to load typical large applications on these systems. ++ * In practice, the slower/faster the device at hand is, the more/less it ++ * takes to load applications with respect to the reference device. ++ * Accordingly, the longer/shorter BFQ grants weight raising to interactive ++ * applications. ++ * ++ * BFQ uses four different reference pairs (R, T), depending on: ++ * . whether the device is rotational or non-rotational; ++ * . whether the device is slow, such as old or portable HDDs, as well as ++ * SD cards, or fast, such as newer HDDs and SSDs. ++ * ++ * The device's speed class is dynamically (re)detected in ++ * bfq_update_peak_rate() every time the estimated peak rate is updated. ++ * ++ * In the following definitions, R_slow[0]/R_fast[0] and T_slow[0]/T_fast[0] ++ * are the reference values for a slow/fast rotational device, whereas ++ * R_slow[1]/R_fast[1] and T_slow[1]/T_fast[1] are the reference values for ++ * a slow/fast non-rotational device. Finally, device_speed_thresh are the ++ * thresholds used to switch between speed classes. ++ * Both the reference peak rates and the thresholds are measured in ++ * sectors/usec, left-shifted by BFQ_RATE_SHIFT. ++ */ ++static int R_slow[2] = {1536, 10752}; ++static int R_fast[2] = {17415, 34791}; ++/* ++ * To improve readability, a conversion function is used to initialize the ++ * following arrays, which entails that they can be initialized only in a ++ * function. ++ */ ++static int T_slow[2]; ++static int T_fast[2]; ++static int device_speed_thresh[2]; ++ ++#define BFQ_SERVICE_TREE_INIT ((struct bfq_service_tree) \ ++ { RB_ROOT, RB_ROOT, NULL, NULL, 0, 0 }) ++ ++#define RQ_BIC(rq) ((struct bfq_io_cq *) (rq)->elv.priv[0]) ++#define RQ_BFQQ(rq) ((rq)->elv.priv[1]) ++ ++static void bfq_schedule_dispatch(struct bfq_data *bfqd); ++ ++#include "bfq-ioc.c" ++#include "bfq-sched.c" ++#include "bfq-cgroup.c" ++ ++#define bfq_class_idle(bfqq) ((bfqq)->ioprio_class == IOPRIO_CLASS_IDLE) ++#define bfq_class_rt(bfqq) ((bfqq)->ioprio_class == IOPRIO_CLASS_RT) ++ ++#define bfq_sample_valid(samples) ((samples) > 80) ++ ++/* ++ * We regard a request as SYNC, if either it's a read or has the SYNC bit ++ * set (in which case it could also be a direct WRITE). ++ */ ++static int bfq_bio_sync(struct bio *bio) ++{ ++ if (bio_data_dir(bio) == READ || (bio->bi_rw & REQ_SYNC)) ++ return 1; ++ ++ return 0; ++} ++ ++/* ++ * Scheduler run of queue, if there are requests pending and no one in the ++ * driver that will restart queueing. ++ */ ++static void bfq_schedule_dispatch(struct bfq_data *bfqd) ++{ ++ if (bfqd->queued != 0) { ++ bfq_log(bfqd, "schedule dispatch"); ++ kblockd_schedule_work(&bfqd->unplug_work); ++ } ++} ++ ++/* ++ * Lifted from AS - choose which of rq1 and rq2 that is best served now. ++ * We choose the request that is closesr to the head right now. Distance ++ * behind the head is penalized and only allowed to a certain extent. ++ */ ++static struct request *bfq_choose_req(struct bfq_data *bfqd, ++ struct request *rq1, ++ struct request *rq2, ++ sector_t last) ++{ ++ sector_t s1, s2, d1 = 0, d2 = 0; ++ unsigned long back_max; ++#define BFQ_RQ1_WRAP 0x01 /* request 1 wraps */ ++#define BFQ_RQ2_WRAP 0x02 /* request 2 wraps */ ++ unsigned wrap = 0; /* bit mask: requests behind the disk head? */ ++ ++ if (!rq1 || rq1 == rq2) ++ return rq2; ++ if (!rq2) ++ return rq1; ++ ++ if (rq_is_sync(rq1) && !rq_is_sync(rq2)) ++ return rq1; ++ else if (rq_is_sync(rq2) && !rq_is_sync(rq1)) ++ return rq2; ++ if ((rq1->cmd_flags & REQ_META) && !(rq2->cmd_flags & REQ_META)) ++ return rq1; ++ else if ((rq2->cmd_flags & REQ_META) && !(rq1->cmd_flags & REQ_META)) ++ return rq2; ++ ++ s1 = blk_rq_pos(rq1); ++ s2 = blk_rq_pos(rq2); ++ ++ /* ++ * By definition, 1KiB is 2 sectors. ++ */ ++ back_max = bfqd->bfq_back_max * 2; ++ ++ /* ++ * Strict one way elevator _except_ in the case where we allow ++ * short backward seeks which are biased as twice the cost of a ++ * similar forward seek. ++ */ ++ if (s1 >= last) ++ d1 = s1 - last; ++ else if (s1 + back_max >= last) ++ d1 = (last - s1) * bfqd->bfq_back_penalty; ++ else ++ wrap |= BFQ_RQ1_WRAP; ++ ++ if (s2 >= last) ++ d2 = s2 - last; ++ else if (s2 + back_max >= last) ++ d2 = (last - s2) * bfqd->bfq_back_penalty; ++ else ++ wrap |= BFQ_RQ2_WRAP; ++ ++ /* Found required data */ ++ ++ /* ++ * By doing switch() on the bit mask "wrap" we avoid having to ++ * check two variables for all permutations: --> faster! ++ */ ++ switch (wrap) { ++ case 0: /* common case for CFQ: rq1 and rq2 not wrapped */ ++ if (d1 < d2) ++ return rq1; ++ else if (d2 < d1) ++ return rq2; ++ else { ++ if (s1 >= s2) ++ return rq1; ++ else ++ return rq2; ++ } ++ ++ case BFQ_RQ2_WRAP: ++ return rq1; ++ case BFQ_RQ1_WRAP: ++ return rq2; ++ case (BFQ_RQ1_WRAP|BFQ_RQ2_WRAP): /* both rqs wrapped */ ++ default: ++ /* ++ * Since both rqs are wrapped, ++ * start with the one that's further behind head ++ * (--> only *one* back seek required), ++ * since back seek takes more time than forward. ++ */ ++ if (s1 <= s2) ++ return rq1; ++ else ++ return rq2; ++ } ++} ++ ++/* ++ * Tell whether there are active queues or groups with differentiated weights. ++ */ ++static bool bfq_differentiated_weights(struct bfq_data *bfqd) ++{ ++ /* ++ * For weights to differ, at least one of the trees must contain ++ * at least two nodes. ++ */ ++ return (!RB_EMPTY_ROOT(&bfqd->queue_weights_tree) && ++ (bfqd->queue_weights_tree.rb_node->rb_left || ++ bfqd->queue_weights_tree.rb_node->rb_right) ++#ifdef CONFIG_BFQ_GROUP_IOSCHED ++ ) || ++ (!RB_EMPTY_ROOT(&bfqd->group_weights_tree) && ++ (bfqd->group_weights_tree.rb_node->rb_left || ++ bfqd->group_weights_tree.rb_node->rb_right) ++#endif ++ ); ++} ++ ++/* ++ * The following function returns true if every queue must receive the ++ * same share of the throughput (this condition is used when deciding ++ * whether idling may be disabled, see the comments in the function ++ * bfq_bfqq_may_idle()). ++ * ++ * Such a scenario occurs when: ++ * 1) all active queues have the same weight, ++ * 2) all active groups at the same level in the groups tree have the same ++ * weight, ++ * 3) all active groups at the same level in the groups tree have the same ++ * number of children. ++ * ++ * Unfortunately, keeping the necessary state for evaluating exactly the ++ * above symmetry conditions would be quite complex and time-consuming. ++ * Therefore this function evaluates, instead, the following stronger ++ * sub-conditions, for which it is much easier to maintain the needed ++ * state: ++ * 1) all active queues have the same weight, ++ * 2) all active groups have the same weight, ++ * 3) all active groups have at most one active child each. ++ * In particular, the last two conditions are always true if hierarchical ++ * support and the cgroups interface are not enabled, thus no state needs ++ * to be maintained in this case. ++ */ ++static bool bfq_symmetric_scenario(struct bfq_data *bfqd) ++{ ++ return ++#ifdef CONFIG_BFQ_GROUP_IOSCHED ++ !bfqd->active_numerous_groups && ++#endif ++ !bfq_differentiated_weights(bfqd); ++} ++ ++/* ++ * If the weight-counter tree passed as input contains no counter for ++ * the weight of the input entity, then add that counter; otherwise just ++ * increment the existing counter. ++ * ++ * Note that weight-counter trees contain few nodes in mostly symmetric ++ * scenarios. For example, if all queues have the same weight, then the ++ * weight-counter tree for the queues may contain at most one node. ++ * This holds even if low_latency is on, because weight-raised queues ++ * are not inserted in the tree. ++ * In most scenarios, the rate at which nodes are created/destroyed ++ * should be low too. ++ */ ++static void bfq_weights_tree_add(struct bfq_data *bfqd, ++ struct bfq_entity *entity, ++ struct rb_root *root) ++{ ++ struct rb_node **new = &(root->rb_node), *parent = NULL; ++ ++ /* ++ * Do not insert if the entity is already associated with a ++ * counter, which happens if: ++ * 1) the entity is associated with a queue, ++ * 2) a request arrival has caused the queue to become both ++ * non-weight-raised, and hence change its weight, and ++ * backlogged; in this respect, each of the two events ++ * causes an invocation of this function, ++ * 3) this is the invocation of this function caused by the ++ * second event. This second invocation is actually useless, ++ * and we handle this fact by exiting immediately. More ++ * efficient or clearer solutions might possibly be adopted. ++ */ ++ if (entity->weight_counter) ++ return; ++ ++ while (*new) { ++ struct bfq_weight_counter *__counter = container_of(*new, ++ struct bfq_weight_counter, ++ weights_node); ++ parent = *new; ++ ++ if (entity->weight == __counter->weight) { ++ entity->weight_counter = __counter; ++ goto inc_counter; ++ } ++ if (entity->weight < __counter->weight) ++ new = &((*new)->rb_left); ++ else ++ new = &((*new)->rb_right); ++ } ++ ++ entity->weight_counter = kzalloc(sizeof(struct bfq_weight_counter), ++ GFP_ATOMIC); ++ entity->weight_counter->weight = entity->weight; ++ rb_link_node(&entity->weight_counter->weights_node, parent, new); ++ rb_insert_color(&entity->weight_counter->weights_node, root); ++ ++inc_counter: ++ entity->weight_counter->num_active++; ++} ++ ++/* ++ * Decrement the weight counter associated with the entity, and, if the ++ * counter reaches 0, remove the counter from the tree. ++ * See the comments to the function bfq_weights_tree_add() for considerations ++ * about overhead. ++ */ ++static void bfq_weights_tree_remove(struct bfq_data *bfqd, ++ struct bfq_entity *entity, ++ struct rb_root *root) ++{ ++ if (!entity->weight_counter) ++ return; ++ ++ BUG_ON(RB_EMPTY_ROOT(root)); ++ BUG_ON(entity->weight_counter->weight != entity->weight); ++ ++ BUG_ON(!entity->weight_counter->num_active); ++ entity->weight_counter->num_active--; ++ if (entity->weight_counter->num_active > 0) ++ goto reset_entity_pointer; ++ ++ rb_erase(&entity->weight_counter->weights_node, root); ++ kfree(entity->weight_counter); ++ ++reset_entity_pointer: ++ entity->weight_counter = NULL; ++} ++ ++static struct request *bfq_find_next_rq(struct bfq_data *bfqd, ++ struct bfq_queue *bfqq, ++ struct request *last) ++{ ++ struct rb_node *rbnext = rb_next(&last->rb_node); ++ struct rb_node *rbprev = rb_prev(&last->rb_node); ++ struct request *next = NULL, *prev = NULL; ++ ++ BUG_ON(RB_EMPTY_NODE(&last->rb_node)); ++ ++ if (rbprev) ++ prev = rb_entry_rq(rbprev); ++ ++ if (rbnext) ++ next = rb_entry_rq(rbnext); ++ else { ++ rbnext = rb_first(&bfqq->sort_list); ++ if (rbnext && rbnext != &last->rb_node) ++ next = rb_entry_rq(rbnext); ++ } ++ ++ return bfq_choose_req(bfqd, next, prev, blk_rq_pos(last)); ++} ++ ++/* see the definition of bfq_async_charge_factor for details */ ++static unsigned long bfq_serv_to_charge(struct request *rq, ++ struct bfq_queue *bfqq) ++{ ++ return blk_rq_sectors(rq) * ++ (1 + ((!bfq_bfqq_sync(bfqq)) * (bfqq->wr_coeff == 1) * ++ bfq_async_charge_factor)); ++} ++ ++/** ++ * bfq_updated_next_req - update the queue after a new next_rq selection. ++ * @bfqd: the device data the queue belongs to. ++ * @bfqq: the queue to update. ++ * ++ * If the first request of a queue changes we make sure that the queue ++ * has enough budget to serve at least its first request (if the ++ * request has grown). We do this because if the queue has not enough ++ * budget for its first request, it has to go through two dispatch ++ * rounds to actually get it dispatched. ++ */ ++static void bfq_updated_next_req(struct bfq_data *bfqd, ++ struct bfq_queue *bfqq) ++{ ++ struct bfq_entity *entity = &bfqq->entity; ++ struct bfq_service_tree *st = bfq_entity_service_tree(entity); ++ struct request *next_rq = bfqq->next_rq; ++ unsigned long new_budget; ++ ++ if (!next_rq) ++ return; ++ ++ if (bfqq == bfqd->in_service_queue) ++ /* ++ * In order not to break guarantees, budgets cannot be ++ * changed after an entity has been selected. ++ */ ++ return; ++ ++ BUG_ON(entity->tree != &st->active); ++ BUG_ON(entity == entity->sched_data->in_service_entity); ++ ++ new_budget = max_t(unsigned long, bfqq->max_budget, ++ bfq_serv_to_charge(next_rq, bfqq)); ++ if (entity->budget != new_budget) { ++ entity->budget = new_budget; ++ bfq_log_bfqq(bfqd, bfqq, "updated next rq: new budget %lu", ++ new_budget); ++ bfq_activate_bfqq(bfqd, bfqq); ++ } ++} ++ ++static unsigned int bfq_wr_duration(struct bfq_data *bfqd) ++{ ++ u64 dur; ++ ++ if (bfqd->bfq_wr_max_time > 0) ++ return bfqd->bfq_wr_max_time; ++ ++ dur = bfqd->RT_prod; ++ do_div(dur, bfqd->peak_rate); ++ ++ return dur; ++} ++ ++/* Empty burst list and add just bfqq (see comments to bfq_handle_burst) */ ++static void bfq_reset_burst_list(struct bfq_data *bfqd, struct bfq_queue *bfqq) ++{ ++ struct bfq_queue *item; ++ struct hlist_node *n; ++ ++ hlist_for_each_entry_safe(item, n, &bfqd->burst_list, burst_list_node) ++ hlist_del_init(&item->burst_list_node); ++ hlist_add_head(&bfqq->burst_list_node, &bfqd->burst_list); ++ bfqd->burst_size = 1; ++} ++ ++/* Add bfqq to the list of queues in current burst (see bfq_handle_burst) */ ++static void bfq_add_to_burst(struct bfq_data *bfqd, struct bfq_queue *bfqq) ++{ ++ /* Increment burst size to take into account also bfqq */ ++ bfqd->burst_size++; ++ ++ if (bfqd->burst_size == bfqd->bfq_large_burst_thresh) { ++ struct bfq_queue *pos, *bfqq_item; ++ struct hlist_node *n; ++ ++ /* ++ * Enough queues have been activated shortly after each ++ * other to consider this burst as large. ++ */ ++ bfqd->large_burst = true; ++ ++ /* ++ * We can now mark all queues in the burst list as ++ * belonging to a large burst. ++ */ ++ hlist_for_each_entry(bfqq_item, &bfqd->burst_list, ++ burst_list_node) ++ bfq_mark_bfqq_in_large_burst(bfqq_item); ++ bfq_mark_bfqq_in_large_burst(bfqq); ++ ++ /* ++ * From now on, and until the current burst finishes, any ++ * new queue being activated shortly after the last queue ++ * was inserted in the burst can be immediately marked as ++ * belonging to a large burst. So the burst list is not ++ * needed any more. Remove it. ++ */ ++ hlist_for_each_entry_safe(pos, n, &bfqd->burst_list, ++ burst_list_node) ++ hlist_del_init(&pos->burst_list_node); ++ } else /* burst not yet large: add bfqq to the burst list */ ++ hlist_add_head(&bfqq->burst_list_node, &bfqd->burst_list); ++} ++ ++/* ++ * If many queues happen to become active shortly after each other, then, ++ * to help the processes associated to these queues get their job done as ++ * soon as possible, it is usually better to not grant either weight-raising ++ * or device idling to these queues. In this comment we describe, firstly, ++ * the reasons why this fact holds, and, secondly, the next function, which ++ * implements the main steps needed to properly mark these queues so that ++ * they can then be treated in a different way. ++ * ++ * As for the terminology, we say that a queue becomes active, i.e., ++ * switches from idle to backlogged, either when it is created (as a ++ * consequence of the arrival of an I/O request), or, if already existing, ++ * when a new request for the queue arrives while the queue is idle. ++ * Bursts of activations, i.e., activations of different queues occurring ++ * shortly after each other, are typically caused by services or applications ++ * that spawn or reactivate many parallel threads/processes. Examples are ++ * systemd during boot or git grep. ++ * ++ * These services or applications benefit mostly from a high throughput: ++ * the quicker the requests of the activated queues are cumulatively served, ++ * the sooner the target job of these queues gets completed. As a consequence, ++ * weight-raising any of these queues, which also implies idling the device ++ * for it, is almost always counterproductive: in most cases it just lowers ++ * throughput. ++ * ++ * On the other hand, a burst of activations may be also caused by the start ++ * of an application that does not consist in a lot of parallel I/O-bound ++ * threads. In fact, with a complex application, the burst may be just a ++ * consequence of the fact that several processes need to be executed to ++ * start-up the application. To start an application as quickly as possible, ++ * the best thing to do is to privilege the I/O related to the application ++ * with respect to all other I/O. Therefore, the best strategy to start as ++ * quickly as possible an application that causes a burst of activations is ++ * to weight-raise all the queues activated during the burst. This is the ++ * exact opposite of the best strategy for the other type of bursts. ++ * ++ * In the end, to take the best action for each of the two cases, the two ++ * types of bursts need to be distinguished. Fortunately, this seems ++ * relatively easy to do, by looking at the sizes of the bursts. In ++ * particular, we found a threshold such that bursts with a larger size ++ * than that threshold are apparently caused only by services or commands ++ * such as systemd or git grep. For brevity, hereafter we call just 'large' ++ * these bursts. BFQ *does not* weight-raise queues whose activations occur ++ * in a large burst. In addition, for each of these queues BFQ performs or ++ * does not perform idling depending on which choice boosts the throughput ++ * most. The exact choice depends on the device and request pattern at ++ * hand. ++ * ++ * Turning back to the next function, it implements all the steps needed ++ * to detect the occurrence of a large burst and to properly mark all the ++ * queues belonging to it (so that they can then be treated in a different ++ * way). This goal is achieved by maintaining a special "burst list" that ++ * holds, temporarily, the queues that belong to the burst in progress. The ++ * list is then used to mark these queues as belonging to a large burst if ++ * the burst does become large. The main steps are the following. ++ * ++ * . when the very first queue is activated, the queue is inserted into the ++ * list (as it could be the first queue in a possible burst) ++ * ++ * . if the current burst has not yet become large, and a queue Q that does ++ * not yet belong to the burst is activated shortly after the last time ++ * at which a new queue entered the burst list, then the function appends ++ * Q to the burst list ++ * ++ * . if, as a consequence of the previous step, the burst size reaches ++ * the large-burst threshold, then ++ * ++ * . all the queues in the burst list are marked as belonging to a ++ * large burst ++ * ++ * . the burst list is deleted; in fact, the burst list already served ++ * its purpose (keeping temporarily track of the queues in a burst, ++ * so as to be able to mark them as belonging to a large burst in the ++ * previous sub-step), and now is not needed any more ++ * ++ * . the device enters a large-burst mode ++ * ++ * . if a queue Q that does not belong to the burst is activated while ++ * the device is in large-burst mode and shortly after the last time ++ * at which a queue either entered the burst list or was marked as ++ * belonging to the current large burst, then Q is immediately marked ++ * as belonging to a large burst. ++ * ++ * . if a queue Q that does not belong to the burst is activated a while ++ * later, i.e., not shortly after, than the last time at which a queue ++ * either entered the burst list or was marked as belonging to the ++ * current large burst, then the current burst is deemed as finished and: ++ * ++ * . the large-burst mode is reset if set ++ * ++ * . the burst list is emptied ++ * ++ * . Q is inserted in the burst list, as Q may be the first queue ++ * in a possible new burst (then the burst list contains just Q ++ * after this step). ++ */ ++static void bfq_handle_burst(struct bfq_data *bfqd, struct bfq_queue *bfqq, ++ bool idle_for_long_time) ++{ ++ /* ++ * If bfqq happened to be activated in a burst, but has been idle ++ * for at least as long as an interactive queue, then we assume ++ * that, in the overall I/O initiated in the burst, the I/O ++ * associated to bfqq is finished. So bfqq does not need to be ++ * treated as a queue belonging to a burst anymore. Accordingly, ++ * we reset bfqq's in_large_burst flag if set, and remove bfqq ++ * from the burst list if it's there. We do not decrement instead ++ * burst_size, because the fact that bfqq does not need to belong ++ * to the burst list any more does not invalidate the fact that ++ * bfqq may have been activated during the current burst. ++ */ ++ if (idle_for_long_time) { ++ hlist_del_init(&bfqq->burst_list_node); ++ bfq_clear_bfqq_in_large_burst(bfqq); ++ } ++ ++ /* ++ * If bfqq is already in the burst list or is part of a large ++ * burst, then there is nothing else to do. ++ */ ++ if (!hlist_unhashed(&bfqq->burst_list_node) || ++ bfq_bfqq_in_large_burst(bfqq)) ++ return; ++ ++ /* ++ * If bfqq's activation happens late enough, then the current ++ * burst is finished, and related data structures must be reset. ++ * ++ * In this respect, consider the special case where bfqq is the very ++ * first queue being activated. In this case, last_ins_in_burst is ++ * not yet significant when we get here. But it is easy to verify ++ * that, whether or not the following condition is true, bfqq will ++ * end up being inserted into the burst list. In particular the ++ * list will happen to contain only bfqq. And this is exactly what ++ * has to happen, as bfqq may be the first queue in a possible ++ * burst. ++ */ ++ if (time_is_before_jiffies(bfqd->last_ins_in_burst + ++ bfqd->bfq_burst_interval)) { ++ bfqd->large_burst = false; ++ bfq_reset_burst_list(bfqd, bfqq); ++ return; ++ } ++ ++ /* ++ * If we get here, then bfqq is being activated shortly after the ++ * last queue. So, if the current burst is also large, we can mark ++ * bfqq as belonging to this large burst immediately. ++ */ ++ if (bfqd->large_burst) { ++ bfq_mark_bfqq_in_large_burst(bfqq); ++ return; ++ } ++ ++ /* ++ * If we get here, then a large-burst state has not yet been ++ * reached, but bfqq is being activated shortly after the last ++ * queue. Then we add bfqq to the burst. ++ */ ++ bfq_add_to_burst(bfqd, bfqq); ++} ++ ++static void bfq_add_request(struct request *rq) ++{ ++ struct bfq_queue *bfqq = RQ_BFQQ(rq); ++ struct bfq_entity *entity = &bfqq->entity; ++ struct bfq_data *bfqd = bfqq->bfqd; ++ struct request *next_rq, *prev; ++ unsigned long old_wr_coeff = bfqq->wr_coeff; ++ bool interactive = false; ++ ++ bfq_log_bfqq(bfqd, bfqq, "add_request %d", rq_is_sync(rq)); ++ bfqq->queued[rq_is_sync(rq)]++; ++ bfqd->queued++; ++ ++ elv_rb_add(&bfqq->sort_list, rq); ++ ++ /* ++ * Check if this request is a better next-serve candidate. ++ */ ++ prev = bfqq->next_rq; ++ next_rq = bfq_choose_req(bfqd, bfqq->next_rq, rq, bfqd->last_position); ++ BUG_ON(!next_rq); ++ bfqq->next_rq = next_rq; ++ ++ if (!bfq_bfqq_busy(bfqq)) { ++ bool soft_rt, in_burst, ++ idle_for_long_time = time_is_before_jiffies( ++ bfqq->budget_timeout + ++ bfqd->bfq_wr_min_idle_time); ++ ++#ifdef CONFIG_BFQ_GROUP_IOSCHED ++ bfqg_stats_update_io_add(bfqq_group(RQ_BFQQ(rq)), bfqq, ++ rq->cmd_flags); ++#endif ++ if (bfq_bfqq_sync(bfqq)) { ++ bool already_in_burst = ++ !hlist_unhashed(&bfqq->burst_list_node) || ++ bfq_bfqq_in_large_burst(bfqq); ++ bfq_handle_burst(bfqd, bfqq, idle_for_long_time); ++ /* ++ * If bfqq was not already in the current burst, ++ * then, at this point, bfqq either has been ++ * added to the current burst or has caused the ++ * current burst to terminate. In particular, in ++ * the second case, bfqq has become the first ++ * queue in a possible new burst. ++ * In both cases last_ins_in_burst needs to be ++ * moved forward. ++ */ ++ if (!already_in_burst) ++ bfqd->last_ins_in_burst = jiffies; ++ } ++ ++ in_burst = bfq_bfqq_in_large_burst(bfqq); ++ soft_rt = bfqd->bfq_wr_max_softrt_rate > 0 && ++ !in_burst && ++ time_is_before_jiffies(bfqq->soft_rt_next_start); ++ interactive = !in_burst && idle_for_long_time; ++ entity->budget = max_t(unsigned long, bfqq->max_budget, ++ bfq_serv_to_charge(next_rq, bfqq)); ++ ++ if (!bfq_bfqq_IO_bound(bfqq)) { ++ if (time_before(jiffies, ++ RQ_BIC(rq)->ttime.last_end_request + ++ bfqd->bfq_slice_idle)) { ++ bfqq->requests_within_timer++; ++ if (bfqq->requests_within_timer >= ++ bfqd->bfq_requests_within_timer) ++ bfq_mark_bfqq_IO_bound(bfqq); ++ } else ++ bfqq->requests_within_timer = 0; ++ } ++ ++ if (!bfqd->low_latency) ++ goto add_bfqq_busy; ++ ++ /* ++ * If the queue: ++ * - is not being boosted, ++ * - has been idle for enough time, ++ * - is not a sync queue or is linked to a bfq_io_cq (it is ++ * shared "for its nature" or it is not shared and its ++ * requests have not been redirected to a shared queue) ++ * start a weight-raising period. ++ */ ++ if (old_wr_coeff == 1 && (interactive || soft_rt) && ++ (!bfq_bfqq_sync(bfqq) || bfqq->bic)) { ++ bfqq->wr_coeff = bfqd->bfq_wr_coeff; ++ if (interactive) ++ bfqq->wr_cur_max_time = bfq_wr_duration(bfqd); ++ else ++ bfqq->wr_cur_max_time = ++ bfqd->bfq_wr_rt_max_time; ++ bfq_log_bfqq(bfqd, bfqq, ++ "wrais starting at %lu, rais_max_time %u", ++ jiffies, ++ jiffies_to_msecs(bfqq->wr_cur_max_time)); ++ } else if (old_wr_coeff > 1) { ++ if (interactive) ++ bfqq->wr_cur_max_time = bfq_wr_duration(bfqd); ++ else if (in_burst || ++ (bfqq->wr_cur_max_time == ++ bfqd->bfq_wr_rt_max_time && ++ !soft_rt)) { ++ bfqq->wr_coeff = 1; ++ bfq_log_bfqq(bfqd, bfqq, ++ "wrais ending at %lu, rais_max_time %u", ++ jiffies, ++ jiffies_to_msecs(bfqq-> ++ wr_cur_max_time)); ++ } else if (time_before( ++ bfqq->last_wr_start_finish + ++ bfqq->wr_cur_max_time, ++ jiffies + ++ bfqd->bfq_wr_rt_max_time) && ++ soft_rt) { ++ /* ++ * ++ * The remaining weight-raising time is lower ++ * than bfqd->bfq_wr_rt_max_time, which means ++ * that the application is enjoying weight ++ * raising either because deemed soft-rt in ++ * the near past, or because deemed interactive ++ * a long ago. ++ * In both cases, resetting now the current ++ * remaining weight-raising time for the ++ * application to the weight-raising duration ++ * for soft rt applications would not cause any ++ * latency increase for the application (as the ++ * new duration would be higher than the ++ * remaining time). ++ * ++ * In addition, the application is now meeting ++ * the requirements for being deemed soft rt. ++ * In the end we can correctly and safely ++ * (re)charge the weight-raising duration for ++ * the application with the weight-raising ++ * duration for soft rt applications. ++ * ++ * In particular, doing this recharge now, i.e., ++ * before the weight-raising period for the ++ * application finishes, reduces the probability ++ * of the following negative scenario: ++ * 1) the weight of a soft rt application is ++ * raised at startup (as for any newly ++ * created application), ++ * 2) since the application is not interactive, ++ * at a certain time weight-raising is ++ * stopped for the application, ++ * 3) at that time the application happens to ++ * still have pending requests, and hence ++ * is destined to not have a chance to be ++ * deemed soft rt before these requests are ++ * completed (see the comments to the ++ * function bfq_bfqq_softrt_next_start() ++ * for details on soft rt detection), ++ * 4) these pending requests experience a high ++ * latency because the application is not ++ * weight-raised while they are pending. ++ */ ++ bfqq->last_wr_start_finish = jiffies; ++ bfqq->wr_cur_max_time = ++ bfqd->bfq_wr_rt_max_time; ++ } ++ } ++ if (old_wr_coeff != bfqq->wr_coeff) ++ entity->prio_changed = 1; ++add_bfqq_busy: ++ bfqq->last_idle_bklogged = jiffies; ++ bfqq->service_from_backlogged = 0; ++ bfq_clear_bfqq_softrt_update(bfqq); ++ bfq_add_bfqq_busy(bfqd, bfqq); ++ } else { ++ if (bfqd->low_latency && old_wr_coeff == 1 && !rq_is_sync(rq) && ++ time_is_before_jiffies( ++ bfqq->last_wr_start_finish + ++ bfqd->bfq_wr_min_inter_arr_async)) { ++ bfqq->wr_coeff = bfqd->bfq_wr_coeff; ++ bfqq->wr_cur_max_time = bfq_wr_duration(bfqd); ++ ++ bfqd->wr_busy_queues++; ++ entity->prio_changed = 1; ++ bfq_log_bfqq(bfqd, bfqq, ++ "non-idle wrais starting at %lu, rais_max_time %u", ++ jiffies, ++ jiffies_to_msecs(bfqq->wr_cur_max_time)); ++ } ++ if (prev != bfqq->next_rq) ++ bfq_updated_next_req(bfqd, bfqq); ++ } ++ ++ if (bfqd->low_latency && ++ (old_wr_coeff == 1 || bfqq->wr_coeff == 1 || interactive)) ++ bfqq->last_wr_start_finish = jiffies; ++} ++ ++static struct request *bfq_find_rq_fmerge(struct bfq_data *bfqd, ++ struct bio *bio) ++{ ++ struct task_struct *tsk = current; ++ struct bfq_io_cq *bic; ++ struct bfq_queue *bfqq; ++ ++ bic = bfq_bic_lookup(bfqd, tsk->io_context); ++ if (!bic) ++ return NULL; ++ ++ bfqq = bic_to_bfqq(bic, bfq_bio_sync(bio)); ++ if (bfqq) ++ return elv_rb_find(&bfqq->sort_list, bio_end_sector(bio)); ++ ++ return NULL; ++} ++ ++static void bfq_activate_request(struct request_queue *q, struct request *rq) ++{ ++ struct bfq_data *bfqd = q->elevator->elevator_data; ++ ++ bfqd->rq_in_driver++; ++ bfqd->last_position = blk_rq_pos(rq) + blk_rq_sectors(rq); ++ bfq_log(bfqd, "activate_request: new bfqd->last_position %llu", ++ (long long unsigned)bfqd->last_position); ++} ++ ++static void bfq_deactivate_request(struct request_queue *q, struct request *rq) ++{ ++ struct bfq_data *bfqd = q->elevator->elevator_data; ++ ++ BUG_ON(bfqd->rq_in_driver == 0); ++ bfqd->rq_in_driver--; ++} ++ ++static void bfq_remove_request(struct request *rq) ++{ ++ struct bfq_queue *bfqq = RQ_BFQQ(rq); ++ struct bfq_data *bfqd = bfqq->bfqd; ++ const int sync = rq_is_sync(rq); ++ ++ if (bfqq->next_rq == rq) { ++ bfqq->next_rq = bfq_find_next_rq(bfqd, bfqq, rq); ++ bfq_updated_next_req(bfqd, bfqq); ++ } ++ ++ if (rq->queuelist.prev != &rq->queuelist) ++ list_del_init(&rq->queuelist); ++ BUG_ON(bfqq->queued[sync] == 0); ++ bfqq->queued[sync]--; ++ bfqd->queued--; ++ elv_rb_del(&bfqq->sort_list, rq); ++ ++ if (RB_EMPTY_ROOT(&bfqq->sort_list)) { ++ if (bfq_bfqq_busy(bfqq) && bfqq != bfqd->in_service_queue) ++ bfq_del_bfqq_busy(bfqd, bfqq, 1); ++ /* ++ * Remove queue from request-position tree as it is empty. ++ */ ++ if (bfqq->pos_root) { ++ rb_erase(&bfqq->pos_node, bfqq->pos_root); ++ bfqq->pos_root = NULL; ++ } ++ } ++ ++ if (rq->cmd_flags & REQ_META) { ++ BUG_ON(bfqq->meta_pending == 0); ++ bfqq->meta_pending--; ++ } ++#ifdef CONFIG_BFQ_GROUP_IOSCHED ++ bfqg_stats_update_io_remove(bfqq_group(bfqq), rq->cmd_flags); ++#endif ++} ++ ++static int bfq_merge(struct request_queue *q, struct request **req, ++ struct bio *bio) ++{ ++ struct bfq_data *bfqd = q->elevator->elevator_data; ++ struct request *__rq; ++ ++ __rq = bfq_find_rq_fmerge(bfqd, bio); ++ if (__rq && elv_rq_merge_ok(__rq, bio)) { ++ *req = __rq; ++ return ELEVATOR_FRONT_MERGE; ++ } ++ ++ return ELEVATOR_NO_MERGE; ++} ++ ++static void bfq_merged_request(struct request_queue *q, struct request *req, ++ int type) ++{ ++ if (type == ELEVATOR_FRONT_MERGE && ++ rb_prev(&req->rb_node) && ++ blk_rq_pos(req) < ++ blk_rq_pos(container_of(rb_prev(&req->rb_node), ++ struct request, rb_node))) { ++ struct bfq_queue *bfqq = RQ_BFQQ(req); ++ struct bfq_data *bfqd = bfqq->bfqd; ++ struct request *prev, *next_rq; ++ ++ /* Reposition request in its sort_list */ ++ elv_rb_del(&bfqq->sort_list, req); ++ elv_rb_add(&bfqq->sort_list, req); ++ /* Choose next request to be served for bfqq */ ++ prev = bfqq->next_rq; ++ next_rq = bfq_choose_req(bfqd, bfqq->next_rq, req, ++ bfqd->last_position); ++ BUG_ON(!next_rq); ++ bfqq->next_rq = next_rq; ++ } ++} ++ ++#ifdef CONFIG_BFQ_GROUP_IOSCHED ++static void bfq_bio_merged(struct request_queue *q, struct request *req, ++ struct bio *bio) ++{ ++ bfqg_stats_update_io_merged(bfqq_group(RQ_BFQQ(req)), bio->bi_rw); ++} ++#endif ++ ++static void bfq_merged_requests(struct request_queue *q, struct request *rq, ++ struct request *next) ++{ ++ struct bfq_queue *bfqq = RQ_BFQQ(rq), *next_bfqq = RQ_BFQQ(next); ++ ++ /* ++ * If next and rq belong to the same bfq_queue and next is older ++ * than rq, then reposition rq in the fifo (by substituting next ++ * with rq). Otherwise, if next and rq belong to different ++ * bfq_queues, never reposition rq: in fact, we would have to ++ * reposition it with respect to next's position in its own fifo, ++ * which would most certainly be too expensive with respect to ++ * the benefits. ++ */ ++ if (bfqq == next_bfqq && ++ !list_empty(&rq->queuelist) && !list_empty(&next->queuelist) && ++ time_before(next->fifo_time, rq->fifo_time)) { ++ list_del_init(&rq->queuelist); ++ list_replace_init(&next->queuelist, &rq->queuelist); ++ rq->fifo_time = next->fifo_time; ++ } ++ ++ if (bfqq->next_rq == next) ++ bfqq->next_rq = rq; ++ ++ bfq_remove_request(next); ++#ifdef CONFIG_BFQ_GROUP_IOSCHED ++ bfqg_stats_update_io_merged(bfqq_group(bfqq), next->cmd_flags); ++#endif ++} ++ ++/* Must be called with bfqq != NULL */ ++static void bfq_bfqq_end_wr(struct bfq_queue *bfqq) ++{ ++ BUG_ON(!bfqq); ++ if (bfq_bfqq_busy(bfqq)) ++ bfqq->bfqd->wr_busy_queues--; ++ bfqq->wr_coeff = 1; ++ bfqq->wr_cur_max_time = 0; ++ /* Trigger a weight change on the next activation of the queue */ ++ bfqq->entity.prio_changed = 1; ++} ++ ++static void bfq_end_wr_async_queues(struct bfq_data *bfqd, ++ struct bfq_group *bfqg) ++{ ++ int i, j; ++ ++ for (i = 0; i < 2; i++) ++ for (j = 0; j < IOPRIO_BE_NR; j++) ++ if (bfqg->async_bfqq[i][j]) ++ bfq_bfqq_end_wr(bfqg->async_bfqq[i][j]); ++ if (bfqg->async_idle_bfqq) ++ bfq_bfqq_end_wr(bfqg->async_idle_bfqq); ++} ++ ++static void bfq_end_wr(struct bfq_data *bfqd) ++{ ++ struct bfq_queue *bfqq; ++ ++ spin_lock_irq(bfqd->queue->queue_lock); ++ ++ list_for_each_entry(bfqq, &bfqd->active_list, bfqq_list) ++ bfq_bfqq_end_wr(bfqq); ++ list_for_each_entry(bfqq, &bfqd->idle_list, bfqq_list) ++ bfq_bfqq_end_wr(bfqq); ++ bfq_end_wr_async(bfqd); ++ ++ spin_unlock_irq(bfqd->queue->queue_lock); ++} ++ ++static int bfq_allow_merge(struct request_queue *q, struct request *rq, ++ struct bio *bio) ++{ ++ struct bfq_data *bfqd = q->elevator->elevator_data; ++ struct bfq_io_cq *bic; ++ ++ /* ++ * Disallow merge of a sync bio into an async request. ++ */ ++ if (bfq_bio_sync(bio) && !rq_is_sync(rq)) ++ return 0; ++ ++ /* ++ * Lookup the bfqq that this bio will be queued with. Allow ++ * merge only if rq is queued there. ++ * Queue lock is held here. ++ */ ++ bic = bfq_bic_lookup(bfqd, current->io_context); ++ if (!bic) ++ return 0; ++ ++ return bic_to_bfqq(bic, bfq_bio_sync(bio)) == RQ_BFQQ(rq); ++} ++ ++static void __bfq_set_in_service_queue(struct bfq_data *bfqd, ++ struct bfq_queue *bfqq) ++{ ++ if (bfqq) { ++#ifdef CONFIG_BFQ_GROUP_IOSCHED ++ bfqg_stats_update_avg_queue_size(bfqq_group(bfqq)); ++#endif ++ bfq_mark_bfqq_must_alloc(bfqq); ++ bfq_mark_bfqq_budget_new(bfqq); ++ bfq_clear_bfqq_fifo_expire(bfqq); ++ ++ bfqd->budgets_assigned = (bfqd->budgets_assigned*7 + 256) / 8; ++ ++ bfq_log_bfqq(bfqd, bfqq, ++ "set_in_service_queue, cur-budget = %d", ++ bfqq->entity.budget); ++ } ++ ++ bfqd->in_service_queue = bfqq; ++} ++ ++/* ++ * Get and set a new queue for service. ++ */ ++static struct bfq_queue *bfq_set_in_service_queue(struct bfq_data *bfqd) ++{ ++ struct bfq_queue *bfqq = bfq_get_next_queue(bfqd); ++ ++ __bfq_set_in_service_queue(bfqd, bfqq); ++ return bfqq; ++} ++ ++/* ++ * If enough samples have been computed, return the current max budget ++ * stored in bfqd, which is dynamically updated according to the ++ * estimated disk peak rate; otherwise return the default max budget ++ */ ++static int bfq_max_budget(struct bfq_data *bfqd) ++{ ++ if (bfqd->budgets_assigned < bfq_stats_min_budgets) ++ return bfq_default_max_budget; ++ else ++ return bfqd->bfq_max_budget; ++} ++ ++/* ++ * Return min budget, which is a fraction of the current or default ++ * max budget (trying with 1/32) ++ */ ++static int bfq_min_budget(struct bfq_data *bfqd) ++{ ++ if (bfqd->budgets_assigned < bfq_stats_min_budgets) ++ return bfq_default_max_budget / 32; ++ else ++ return bfqd->bfq_max_budget / 32; ++} ++ ++static void bfq_arm_slice_timer(struct bfq_data *bfqd) ++{ ++ struct bfq_queue *bfqq = bfqd->in_service_queue; ++ struct bfq_io_cq *bic; ++ unsigned long sl; ++ ++ BUG_ON(!RB_EMPTY_ROOT(&bfqq->sort_list)); ++ ++ /* Processes have exited, don't wait. */ ++ bic = bfqd->in_service_bic; ++ if (!bic || atomic_read(&bic->icq.ioc->active_ref) == 0) ++ return; ++ ++ bfq_mark_bfqq_wait_request(bfqq); ++ ++ /* ++ * We don't want to idle for seeks, but we do want to allow ++ * fair distribution of slice time for a process doing back-to-back ++ * seeks. So allow a little bit of time for him to submit a new rq. ++ * ++ * To prevent processes with (partly) seeky workloads from ++ * being too ill-treated, grant them a small fraction of the ++ * assigned budget before reducing the waiting time to ++ * BFQ_MIN_TT. This happened to help reduce latency. ++ */ ++ sl = bfqd->bfq_slice_idle; ++ /* ++ * Unless the queue is being weight-raised or the scenario is ++ * asymmetric, grant only minimum idle time if the queue either ++ * has been seeky for long enough or has already proved to be ++ * constantly seeky. ++ */ ++ if (bfq_sample_valid(bfqq->seek_samples) && ++ ((BFQQ_SEEKY(bfqq) && bfqq->entity.service > ++ bfq_max_budget(bfqq->bfqd) / 8) || ++ bfq_bfqq_constantly_seeky(bfqq)) && bfqq->wr_coeff == 1 && ++ bfq_symmetric_scenario(bfqd)) ++ sl = min(sl, msecs_to_jiffies(BFQ_MIN_TT)); ++ else if (bfqq->wr_coeff > 1) ++ sl = sl * 3; ++ bfqd->last_idling_start = ktime_get(); ++ mod_timer(&bfqd->idle_slice_timer, jiffies + sl); ++#ifdef CONFIG_BFQ_GROUP_IOSCHED ++ bfqg_stats_set_start_idle_time(bfqq_group(bfqq)); ++#endif ++ bfq_log(bfqd, "arm idle: %u/%u ms", ++ jiffies_to_msecs(sl), jiffies_to_msecs(bfqd->bfq_slice_idle)); ++} ++ ++/* ++ * Set the maximum time for the in-service queue to consume its ++ * budget. This prevents seeky processes from lowering the disk ++ * throughput (always guaranteed with a time slice scheme as in CFQ). ++ */ ++static void bfq_set_budget_timeout(struct bfq_data *bfqd) ++{ ++ struct bfq_queue *bfqq = bfqd->in_service_queue; ++ unsigned int timeout_coeff; ++ if (bfqq->wr_cur_max_time == bfqd->bfq_wr_rt_max_time) ++ timeout_coeff = 1; ++ else ++ timeout_coeff = bfqq->entity.weight / bfqq->entity.orig_weight; ++ ++ bfqd->last_budget_start = ktime_get(); ++ ++ bfq_clear_bfqq_budget_new(bfqq); ++ bfqq->budget_timeout = jiffies + ++ bfqd->bfq_timeout[bfq_bfqq_sync(bfqq)] * timeout_coeff; ++ ++ bfq_log_bfqq(bfqd, bfqq, "set budget_timeout %u", ++ jiffies_to_msecs(bfqd->bfq_timeout[bfq_bfqq_sync(bfqq)] * ++ timeout_coeff)); ++} ++ ++/* ++ * Move request from internal lists to the request queue dispatch list. ++ */ ++static void bfq_dispatch_insert(struct request_queue *q, struct request *rq) ++{ ++ struct bfq_data *bfqd = q->elevator->elevator_data; ++ struct bfq_queue *bfqq = RQ_BFQQ(rq); ++ ++ /* ++ * For consistency, the next instruction should have been executed ++ * after removing the request from the queue and dispatching it. ++ * We execute instead this instruction before bfq_remove_request() ++ * (and hence introduce a temporary inconsistency), for efficiency. ++ * In fact, in a forced_dispatch, this prevents two counters related ++ * to bfqq->dispatched to risk to be uselessly decremented if bfqq ++ * is not in service, and then to be incremented again after ++ * incrementing bfqq->dispatched. ++ */ ++ bfqq->dispatched++; ++ bfq_remove_request(rq); ++ elv_dispatch_sort(q, rq); ++ ++ if (bfq_bfqq_sync(bfqq)) ++ bfqd->sync_flight++; ++#ifdef CONFIG_BFQ_GROUP_IOSCHED ++ bfqg_stats_update_dispatch(bfqq_group(bfqq), blk_rq_bytes(rq), ++ rq->cmd_flags); ++#endif ++} ++ ++/* ++ * Return expired entry, or NULL to just start from scratch in rbtree. ++ */ ++static struct request *bfq_check_fifo(struct bfq_queue *bfqq) ++{ ++ struct request *rq = NULL; ++ ++ if (bfq_bfqq_fifo_expire(bfqq)) ++ return NULL; ++ ++ bfq_mark_bfqq_fifo_expire(bfqq); ++ ++ if (list_empty(&bfqq->fifo)) ++ return NULL; ++ ++ rq = rq_entry_fifo(bfqq->fifo.next); ++ ++ if (time_before(jiffies, rq->fifo_time)) ++ return NULL; ++ ++ return rq; ++} ++ ++static int bfq_bfqq_budget_left(struct bfq_queue *bfqq) ++{ ++ struct bfq_entity *entity = &bfqq->entity; ++ return entity->budget - entity->service; ++} ++ ++static void __bfq_bfqq_expire(struct bfq_data *bfqd, struct bfq_queue *bfqq) ++{ ++ BUG_ON(bfqq != bfqd->in_service_queue); ++ ++ __bfq_bfqd_reset_in_service(bfqd); ++ ++ if (RB_EMPTY_ROOT(&bfqq->sort_list)) { ++ /* ++ * Overloading budget_timeout field to store the time ++ * at which the queue remains with no backlog; used by ++ * the weight-raising mechanism. ++ */ ++ bfqq->budget_timeout = jiffies; ++ bfq_del_bfqq_busy(bfqd, bfqq, 1); ++ } else ++ bfq_activate_bfqq(bfqd, bfqq); ++} ++ ++/** ++ * __bfq_bfqq_recalc_budget - try to adapt the budget to the @bfqq behavior. ++ * @bfqd: device data. ++ * @bfqq: queue to update. ++ * @reason: reason for expiration. ++ * ++ * Handle the feedback on @bfqq budget at queue expiration. ++ * See the body for detailed comments. ++ */ ++static void __bfq_bfqq_recalc_budget(struct bfq_data *bfqd, ++ struct bfq_queue *bfqq, ++ enum bfqq_expiration reason) ++{ ++ struct request *next_rq; ++ int budget, min_budget; ++ ++ budget = bfqq->max_budget; ++ min_budget = bfq_min_budget(bfqd); ++ ++ BUG_ON(bfqq != bfqd->in_service_queue); ++ ++ bfq_log_bfqq(bfqd, bfqq, "recalc_budg: last budg %d, budg left %d", ++ bfqq->entity.budget, bfq_bfqq_budget_left(bfqq)); ++ bfq_log_bfqq(bfqd, bfqq, "recalc_budg: last max_budg %d, min budg %d", ++ budget, bfq_min_budget(bfqd)); ++ bfq_log_bfqq(bfqd, bfqq, "recalc_budg: sync %d, seeky %d", ++ bfq_bfqq_sync(bfqq), BFQQ_SEEKY(bfqd->in_service_queue)); ++ ++ if (bfq_bfqq_sync(bfqq)) { ++ switch (reason) { ++ /* ++ * Caveat: in all the following cases we trade latency ++ * for throughput. ++ */ ++ case BFQ_BFQQ_TOO_IDLE: ++ /* ++ * This is the only case where we may reduce ++ * the budget: if there is no request of the ++ * process still waiting for completion, then ++ * we assume (tentatively) that the timer has ++ * expired because the batch of requests of ++ * the process could have been served with a ++ * smaller budget. Hence, betting that ++ * process will behave in the same way when it ++ * becomes backlogged again, we reduce its ++ * next budget. As long as we guess right, ++ * this budget cut reduces the latency ++ * experienced by the process. ++ * ++ * However, if there are still outstanding ++ * requests, then the process may have not yet ++ * issued its next request just because it is ++ * still waiting for the completion of some of ++ * the still outstanding ones. So in this ++ * subcase we do not reduce its budget, on the ++ * contrary we increase it to possibly boost ++ * the throughput, as discussed in the ++ * comments to the BUDGET_TIMEOUT case. ++ */ ++ if (bfqq->dispatched > 0) /* still outstanding reqs */ ++ budget = min(budget * 2, bfqd->bfq_max_budget); ++ else { ++ if (budget > 5 * min_budget) ++ budget -= 4 * min_budget; ++ else ++ budget = min_budget; ++ } ++ break; ++ case BFQ_BFQQ_BUDGET_TIMEOUT: ++ /* ++ * We double the budget here because: 1) it ++ * gives the chance to boost the throughput if ++ * this is not a seeky process (which may have ++ * bumped into this timeout because of, e.g., ++ * ZBR), 2) together with charge_full_budget ++ * it helps give seeky processes higher ++ * timestamps, and hence be served less ++ * frequently. ++ */ ++ budget = min(budget * 2, bfqd->bfq_max_budget); ++ break; ++ case BFQ_BFQQ_BUDGET_EXHAUSTED: ++ /* ++ * The process still has backlog, and did not ++ * let either the budget timeout or the disk ++ * idling timeout expire. Hence it is not ++ * seeky, has a short thinktime and may be ++ * happy with a higher budget too. So ++ * definitely increase the budget of this good ++ * candidate to boost the disk throughput. ++ */ ++ budget = min(budget * 4, bfqd->bfq_max_budget); ++ break; ++ case BFQ_BFQQ_NO_MORE_REQUESTS: ++ /* ++ * Leave the budget unchanged. ++ */ ++ default: ++ return; ++ } ++ } else ++ /* ++ * Async queues get always the maximum possible budget ++ * (their ability to dispatch is limited by ++ * @bfqd->bfq_max_budget_async_rq). ++ */ ++ budget = bfqd->bfq_max_budget; ++ ++ bfqq->max_budget = budget; ++ ++ if (bfqd->budgets_assigned >= bfq_stats_min_budgets && ++ !bfqd->bfq_user_max_budget) ++ bfqq->max_budget = min(bfqq->max_budget, bfqd->bfq_max_budget); ++ ++ /* ++ * Make sure that we have enough budget for the next request. ++ * Since the finish time of the bfqq must be kept in sync with ++ * the budget, be sure to call __bfq_bfqq_expire() after the ++ * update. ++ */ ++ next_rq = bfqq->next_rq; ++ if (next_rq) ++ bfqq->entity.budget = max_t(unsigned long, bfqq->max_budget, ++ bfq_serv_to_charge(next_rq, bfqq)); ++ else ++ bfqq->entity.budget = bfqq->max_budget; ++ ++ bfq_log_bfqq(bfqd, bfqq, "head sect: %u, new budget %d", ++ next_rq ? blk_rq_sectors(next_rq) : 0, ++ bfqq->entity.budget); ++} ++ ++static unsigned long bfq_calc_max_budget(u64 peak_rate, u64 timeout) ++{ ++ unsigned long max_budget; ++ ++ /* ++ * The max_budget calculated when autotuning is equal to the ++ * amount of sectors transfered in timeout_sync at the ++ * estimated peak rate. ++ */ ++ max_budget = (unsigned long)(peak_rate * 1000 * ++ timeout >> BFQ_RATE_SHIFT); ++ ++ return max_budget; ++} ++ ++/* ++ * In addition to updating the peak rate, checks whether the process ++ * is "slow", and returns 1 if so. This slow flag is used, in addition ++ * to the budget timeout, to reduce the amount of service provided to ++ * seeky processes, and hence reduce their chances to lower the ++ * throughput. See the code for more details. ++ */ ++static bool bfq_update_peak_rate(struct bfq_data *bfqd, struct bfq_queue *bfqq, ++ bool compensate, enum bfqq_expiration reason) ++{ ++ u64 bw, usecs, expected, timeout; ++ ktime_t delta; ++ int update = 0; ++ ++ if (!bfq_bfqq_sync(bfqq) || bfq_bfqq_budget_new(bfqq)) ++ return false; ++ ++ if (compensate) ++ delta = bfqd->last_idling_start; ++ else ++ delta = ktime_get(); ++ delta = ktime_sub(delta, bfqd->last_budget_start); ++ usecs = ktime_to_us(delta); ++ ++ /* Don't trust short/unrealistic values. */ ++ if (usecs < 100 || usecs >= LONG_MAX) ++ return false; ++ ++ /* ++ * Calculate the bandwidth for the last slice. We use a 64 bit ++ * value to store the peak rate, in sectors per usec in fixed ++ * point math. We do so to have enough precision in the estimate ++ * and to avoid overflows. ++ */ ++ bw = (u64)bfqq->entity.service << BFQ_RATE_SHIFT; ++ do_div(bw, (unsigned long)usecs); ++ ++ timeout = jiffies_to_msecs(bfqd->bfq_timeout[BLK_RW_SYNC]); ++ ++ /* ++ * Use only long (> 20ms) intervals to filter out spikes for ++ * the peak rate estimation. ++ */ ++ if (usecs > 20000) { ++ if (bw > bfqd->peak_rate || ++ (!BFQQ_SEEKY(bfqq) && ++ reason == BFQ_BFQQ_BUDGET_TIMEOUT)) { ++ bfq_log(bfqd, "measured bw =%llu", bw); ++ /* ++ * To smooth oscillations use a low-pass filter with ++ * alpha=7/8, i.e., ++ * new_rate = (7/8) * old_rate + (1/8) * bw ++ */ ++ do_div(bw, 8); ++ if (bw == 0) ++ return 0; ++ bfqd->peak_rate *= 7; ++ do_div(bfqd->peak_rate, 8); ++ bfqd->peak_rate += bw; ++ update = 1; ++ bfq_log(bfqd, "new peak_rate=%llu", bfqd->peak_rate); ++ } ++ ++ update |= bfqd->peak_rate_samples == BFQ_PEAK_RATE_SAMPLES - 1; ++ ++ if (bfqd->peak_rate_samples < BFQ_PEAK_RATE_SAMPLES) ++ bfqd->peak_rate_samples++; ++ ++ if (bfqd->peak_rate_samples == BFQ_PEAK_RATE_SAMPLES && ++ update) { ++ int dev_type = blk_queue_nonrot(bfqd->queue); ++ if (bfqd->bfq_user_max_budget == 0) { ++ bfqd->bfq_max_budget = ++ bfq_calc_max_budget(bfqd->peak_rate, ++ timeout); ++ bfq_log(bfqd, "new max_budget=%d", ++ bfqd->bfq_max_budget); ++ } ++ if (bfqd->device_speed == BFQ_BFQD_FAST && ++ bfqd->peak_rate < device_speed_thresh[dev_type]) { ++ bfqd->device_speed = BFQ_BFQD_SLOW; ++ bfqd->RT_prod = R_slow[dev_type] * ++ T_slow[dev_type]; ++ } else if (bfqd->device_speed == BFQ_BFQD_SLOW && ++ bfqd->peak_rate > device_speed_thresh[dev_type]) { ++ bfqd->device_speed = BFQ_BFQD_FAST; ++ bfqd->RT_prod = R_fast[dev_type] * ++ T_fast[dev_type]; ++ } ++ } ++ } ++ ++ /* ++ * If the process has been served for a too short time ++ * interval to let its possible sequential accesses prevail on ++ * the initial seek time needed to move the disk head on the ++ * first sector it requested, then give the process a chance ++ * and for the moment return false. ++ */ ++ if (bfqq->entity.budget <= bfq_max_budget(bfqd) / 8) ++ return false; ++ ++ /* ++ * A process is considered ``slow'' (i.e., seeky, so that we ++ * cannot treat it fairly in the service domain, as it would ++ * slow down too much the other processes) if, when a slice ++ * ends for whatever reason, it has received service at a ++ * rate that would not be high enough to complete the budget ++ * before the budget timeout expiration. ++ */ ++ expected = bw * 1000 * timeout >> BFQ_RATE_SHIFT; ++ ++ /* ++ * Caveat: processes doing IO in the slower disk zones will ++ * tend to be slow(er) even if not seeky. And the estimated ++ * peak rate will actually be an average over the disk ++ * surface. Hence, to not be too harsh with unlucky processes, ++ * we keep a budget/3 margin of safety before declaring a ++ * process slow. ++ */ ++ return expected > (4 * bfqq->entity.budget) / 3; ++} ++ ++/* ++ * To be deemed as soft real-time, an application must meet two ++ * requirements. First, the application must not require an average ++ * bandwidth higher than the approximate bandwidth required to playback or ++ * record a compressed high-definition video. ++ * The next function is invoked on the completion of the last request of a ++ * batch, to compute the next-start time instant, soft_rt_next_start, such ++ * that, if the next request of the application does not arrive before ++ * soft_rt_next_start, then the above requirement on the bandwidth is met. ++ * ++ * The second requirement is that the request pattern of the application is ++ * isochronous, i.e., that, after issuing a request or a batch of requests, ++ * the application stops issuing new requests until all its pending requests ++ * have been completed. After that, the application may issue a new batch, ++ * and so on. ++ * For this reason the next function is invoked to compute ++ * soft_rt_next_start only for applications that meet this requirement, ++ * whereas soft_rt_next_start is set to infinity for applications that do ++ * not. ++ * ++ * Unfortunately, even a greedy application may happen to behave in an ++ * isochronous way if the CPU load is high. In fact, the application may ++ * stop issuing requests while the CPUs are busy serving other processes, ++ * then restart, then stop again for a while, and so on. In addition, if ++ * the disk achieves a low enough throughput with the request pattern ++ * issued by the application (e.g., because the request pattern is random ++ * and/or the device is slow), then the application may meet the above ++ * bandwidth requirement too. To prevent such a greedy application to be ++ * deemed as soft real-time, a further rule is used in the computation of ++ * soft_rt_next_start: soft_rt_next_start must be higher than the current ++ * time plus the maximum time for which the arrival of a request is waited ++ * for when a sync queue becomes idle, namely bfqd->bfq_slice_idle. ++ * This filters out greedy applications, as the latter issue instead their ++ * next request as soon as possible after the last one has been completed ++ * (in contrast, when a batch of requests is completed, a soft real-time ++ * application spends some time processing data). ++ * ++ * Unfortunately, the last filter may easily generate false positives if ++ * only bfqd->bfq_slice_idle is used as a reference time interval and one ++ * or both the following cases occur: ++ * 1) HZ is so low that the duration of a jiffy is comparable to or higher ++ * than bfqd->bfq_slice_idle. This happens, e.g., on slow devices with ++ * HZ=100. ++ * 2) jiffies, instead of increasing at a constant rate, may stop increasing ++ * for a while, then suddenly 'jump' by several units to recover the lost ++ * increments. This seems to happen, e.g., inside virtual machines. ++ * To address this issue, we do not use as a reference time interval just ++ * bfqd->bfq_slice_idle, but bfqd->bfq_slice_idle plus a few jiffies. In ++ * particular we add the minimum number of jiffies for which the filter ++ * seems to be quite precise also in embedded systems and KVM/QEMU virtual ++ * machines. ++ */ ++static unsigned long bfq_bfqq_softrt_next_start(struct bfq_data *bfqd, ++ struct bfq_queue *bfqq) ++{ ++ return max(bfqq->last_idle_bklogged + ++ HZ * bfqq->service_from_backlogged / ++ bfqd->bfq_wr_max_softrt_rate, ++ jiffies + bfqq->bfqd->bfq_slice_idle + 4); ++} ++ ++/* ++ * Return the largest-possible time instant such that, for as long as possible, ++ * the current time will be lower than this time instant according to the macro ++ * time_is_before_jiffies(). ++ */ ++static unsigned long bfq_infinity_from_now(unsigned long now) ++{ ++ return now + ULONG_MAX / 2; ++} ++ ++/** ++ * bfq_bfqq_expire - expire a queue. ++ * @bfqd: device owning the queue. ++ * @bfqq: the queue to expire. ++ * @compensate: if true, compensate for the time spent idling. ++ * @reason: the reason causing the expiration. ++ * ++ * ++ * If the process associated to the queue is slow (i.e., seeky), or in ++ * case of budget timeout, or, finally, if it is async, we ++ * artificially charge it an entire budget (independently of the ++ * actual service it received). As a consequence, the queue will get ++ * higher timestamps than the correct ones upon reactivation, and ++ * hence it will be rescheduled as if it had received more service ++ * than what it actually received. In the end, this class of processes ++ * will receive less service in proportion to how slowly they consume ++ * their budgets (and hence how seriously they tend to lower the ++ * throughput). ++ * ++ * In contrast, when a queue expires because it has been idling for ++ * too much or because it exhausted its budget, we do not touch the ++ * amount of service it has received. Hence when the queue will be ++ * reactivated and its timestamps updated, the latter will be in sync ++ * with the actual service received by the queue until expiration. ++ * ++ * Charging a full budget to the first type of queues and the exact ++ * service to the others has the effect of using the WF2Q+ policy to ++ * schedule the former on a timeslice basis, without violating the ++ * service domain guarantees of the latter. ++ */ ++static void bfq_bfqq_expire(struct bfq_data *bfqd, ++ struct bfq_queue *bfqq, ++ bool compensate, ++ enum bfqq_expiration reason) ++{ ++ bool slow; ++ BUG_ON(bfqq != bfqd->in_service_queue); ++ ++ /* ++ * Update disk peak rate for autotuning and check whether the ++ * process is slow (see bfq_update_peak_rate). ++ */ ++ slow = bfq_update_peak_rate(bfqd, bfqq, compensate, reason); ++ ++ /* ++ * As above explained, 'punish' slow (i.e., seeky), timed-out ++ * and async queues, to favor sequential sync workloads. ++ * ++ * Processes doing I/O in the slower disk zones will tend to be ++ * slow(er) even if not seeky. Hence, since the estimated peak ++ * rate is actually an average over the disk surface, these ++ * processes may timeout just for bad luck. To avoid punishing ++ * them we do not charge a full budget to a process that ++ * succeeded in consuming at least 2/3 of its budget. ++ */ ++ if (slow || (reason == BFQ_BFQQ_BUDGET_TIMEOUT && ++ bfq_bfqq_budget_left(bfqq) >= bfqq->entity.budget / 3)) ++ bfq_bfqq_charge_full_budget(bfqq); ++ ++ bfqq->service_from_backlogged += bfqq->entity.service; ++ ++ if (BFQQ_SEEKY(bfqq) && reason == BFQ_BFQQ_BUDGET_TIMEOUT && ++ !bfq_bfqq_constantly_seeky(bfqq)) { ++ bfq_mark_bfqq_constantly_seeky(bfqq); ++ if (!blk_queue_nonrot(bfqd->queue)) ++ bfqd->const_seeky_busy_in_flight_queues++; ++ } ++ ++ if (reason == BFQ_BFQQ_TOO_IDLE && ++ bfqq->entity.service <= 2 * bfqq->entity.budget / 10 ) ++ bfq_clear_bfqq_IO_bound(bfqq); ++ ++ if (bfqd->low_latency && bfqq->wr_coeff == 1) ++ bfqq->last_wr_start_finish = jiffies; ++ ++ if (bfqd->low_latency && bfqd->bfq_wr_max_softrt_rate > 0 && ++ RB_EMPTY_ROOT(&bfqq->sort_list)) { ++ /* ++ * If we get here, and there are no outstanding requests, ++ * then the request pattern is isochronous (see the comments ++ * to the function bfq_bfqq_softrt_next_start()). Hence we ++ * can compute soft_rt_next_start. If, instead, the queue ++ * still has outstanding requests, then we have to wait ++ * for the completion of all the outstanding requests to ++ * discover whether the request pattern is actually ++ * isochronous. ++ */ ++ if (bfqq->dispatched == 0) ++ bfqq->soft_rt_next_start = ++ bfq_bfqq_softrt_next_start(bfqd, bfqq); ++ else { ++ /* ++ * The application is still waiting for the ++ * completion of one or more requests: ++ * prevent it from possibly being incorrectly ++ * deemed as soft real-time by setting its ++ * soft_rt_next_start to infinity. In fact, ++ * without this assignment, the application ++ * would be incorrectly deemed as soft ++ * real-time if: ++ * 1) it issued a new request before the ++ * completion of all its in-flight ++ * requests, and ++ * 2) at that time, its soft_rt_next_start ++ * happened to be in the past. ++ */ ++ bfqq->soft_rt_next_start = ++ bfq_infinity_from_now(jiffies); ++ /* ++ * Schedule an update of soft_rt_next_start to when ++ * the task may be discovered to be isochronous. ++ */ ++ bfq_mark_bfqq_softrt_update(bfqq); ++ } ++ } ++ ++ bfq_log_bfqq(bfqd, bfqq, ++ "expire (%d, slow %d, num_disp %d, idle_win %d)", reason, ++ slow, bfqq->dispatched, bfq_bfqq_idle_window(bfqq)); ++ ++ /* ++ * Increase, decrease or leave budget unchanged according to ++ * reason. ++ */ ++ __bfq_bfqq_recalc_budget(bfqd, bfqq, reason); ++ __bfq_bfqq_expire(bfqd, bfqq); ++} ++ ++/* ++ * Budget timeout is not implemented through a dedicated timer, but ++ * just checked on request arrivals and completions, as well as on ++ * idle timer expirations. ++ */ ++static bool bfq_bfqq_budget_timeout(struct bfq_queue *bfqq) ++{ ++ if (bfq_bfqq_budget_new(bfqq) || ++ time_before(jiffies, bfqq->budget_timeout)) ++ return false; ++ return true; ++} ++ ++/* ++ * If we expire a queue that is waiting for the arrival of a new ++ * request, we may prevent the fictitious timestamp back-shifting that ++ * allows the guarantees of the queue to be preserved (see [1] for ++ * this tricky aspect). Hence we return true only if this condition ++ * does not hold, or if the queue is slow enough to deserve only to be ++ * kicked off for preserving a high throughput. ++*/ ++static bool bfq_may_expire_for_budg_timeout(struct bfq_queue *bfqq) ++{ ++ bfq_log_bfqq(bfqq->bfqd, bfqq, ++ "may_budget_timeout: wait_request %d left %d timeout %d", ++ bfq_bfqq_wait_request(bfqq), ++ bfq_bfqq_budget_left(bfqq) >= bfqq->entity.budget / 3, ++ bfq_bfqq_budget_timeout(bfqq)); ++ ++ return (!bfq_bfqq_wait_request(bfqq) || ++ bfq_bfqq_budget_left(bfqq) >= bfqq->entity.budget / 3) ++ && ++ bfq_bfqq_budget_timeout(bfqq); ++} ++ ++/* ++ * For a queue that becomes empty, device idling is allowed only if ++ * this function returns true for that queue. As a consequence, since ++ * device idling plays a critical role for both throughput boosting ++ * and service guarantees, the return value of this function plays a ++ * critical role as well. ++ * ++ * In a nutshell, this function returns true only if idling is ++ * beneficial for throughput or, even if detrimental for throughput, ++ * idling is however necessary to preserve service guarantees (low ++ * latency, desired throughput distribution, ...). In particular, on ++ * NCQ-capable devices, this function tries to return false, so as to ++ * help keep the drives' internal queues full, whenever this helps the ++ * device boost the throughput without causing any service-guarantee ++ * issue. ++ * ++ * In more detail, the return value of this function is obtained by, ++ * first, computing a number of boolean variables that take into ++ * account throughput and service-guarantee issues, and, then, ++ * combining these variables in a logical expression. Most of the ++ * issues taken into account are not trivial. We discuss these issues ++ * while introducing the variables. ++ */ ++static bool bfq_bfqq_may_idle(struct bfq_queue *bfqq) ++{ ++ struct bfq_data *bfqd = bfqq->bfqd; ++ bool idling_boosts_thr, idling_boosts_thr_without_issues, ++ all_queues_seeky, on_hdd_and_not_all_queues_seeky, ++ idling_needed_for_service_guarantees, ++ asymmetric_scenario; ++ ++ /* ++ * The next variable takes into account the cases where idling ++ * boosts the throughput. ++ * ++ * The value of the variable is computed considering, first, that ++ * idling is virtually always beneficial for the throughput if: ++ * (a) the device is not NCQ-capable, or ++ * (b) regardless of the presence of NCQ, the device is rotational ++ * and the request pattern for bfqq is I/O-bound and sequential. ++ * ++ * Secondly, and in contrast to the above item (b), idling an ++ * NCQ-capable flash-based device would not boost the ++ * throughput even with sequential I/O; rather it would lower ++ * the throughput in proportion to how fast the device ++ * is. Accordingly, the next variable is true if any of the ++ * above conditions (a) and (b) is true, and, in particular, ++ * happens to be false if bfqd is an NCQ-capable flash-based ++ * device. ++ */ ++ idling_boosts_thr = !bfqd->hw_tag || ++ (!blk_queue_nonrot(bfqd->queue) && bfq_bfqq_IO_bound(bfqq) && ++ bfq_bfqq_idle_window(bfqq)) ; ++ ++ /* ++ * The value of the next variable, ++ * idling_boosts_thr_without_issues, is equal to that of ++ * idling_boosts_thr, unless a special case holds. In this ++ * special case, described below, idling may cause problems to ++ * weight-raised queues. ++ * ++ * When the request pool is saturated (e.g., in the presence ++ * of write hogs), if the processes associated with ++ * non-weight-raised queues ask for requests at a lower rate, ++ * then processes associated with weight-raised queues have a ++ * higher probability to get a request from the pool ++ * immediately (or at least soon) when they need one. Thus ++ * they have a higher probability to actually get a fraction ++ * of the device throughput proportional to their high ++ * weight. This is especially true with NCQ-capable drives, ++ * which enqueue several requests in advance, and further ++ * reorder internally-queued requests. ++ * ++ * For this reason, we force to false the value of ++ * idling_boosts_thr_without_issues if there are weight-raised ++ * busy queues. In this case, and if bfqq is not weight-raised, ++ * this guarantees that the device is not idled for bfqq (if, ++ * instead, bfqq is weight-raised, then idling will be ++ * guaranteed by another variable, see below). Combined with ++ * the timestamping rules of BFQ (see [1] for details), this ++ * behavior causes bfqq, and hence any sync non-weight-raised ++ * queue, to get a lower number of requests served, and thus ++ * to ask for a lower number of requests from the request ++ * pool, before the busy weight-raised queues get served ++ * again. This often mitigates starvation problems in the ++ * presence of heavy write workloads and NCQ, thereby ++ * guaranteeing a higher application and system responsiveness ++ * in these hostile scenarios. ++ */ ++ idling_boosts_thr_without_issues = idling_boosts_thr && ++ bfqd->wr_busy_queues == 0; ++ ++ /* ++ * There are then two cases where idling must be performed not ++ * for throughput concerns, but to preserve service ++ * guarantees. In the description of these cases, we say, for ++ * short, that a queue is sequential/random if the process ++ * associated to the queue issues sequential/random requests ++ * (in the second case the queue may be tagged as seeky or ++ * even constantly_seeky). ++ * ++ * To introduce the first case, we note that, since ++ * bfq_bfqq_idle_window(bfqq) is false if the device is ++ * NCQ-capable and bfqq is random (see ++ * bfq_update_idle_window()), then, from the above two ++ * assignments it follows that ++ * idling_boosts_thr_without_issues is false if the device is ++ * NCQ-capable and bfqq is random. Therefore, for this case, ++ * device idling would never be allowed if we used just ++ * idling_boosts_thr_without_issues to decide whether to allow ++ * it. And, beneficially, this would imply that throughput ++ * would always be boosted also with random I/O on NCQ-capable ++ * HDDs. ++ * ++ * But we must be careful on this point, to avoid an unfair ++ * treatment for bfqq. In fact, because of the same above ++ * assignments, idling_boosts_thr_without_issues is, on the ++ * other hand, true if 1) the device is an HDD and bfqq is ++ * sequential, and 2) there are no busy weight-raised ++ * queues. As a consequence, if we used just ++ * idling_boosts_thr_without_issues to decide whether to idle ++ * the device, then with an HDD we might easily bump into a ++ * scenario where queues that are sequential and I/O-bound ++ * would enjoy idling, whereas random queues would not. The ++ * latter might then get a low share of the device throughput, ++ * simply because the former would get many requests served ++ * after being set as in service, while the latter would not. ++ * ++ * To address this issue, we start by setting to true a ++ * sentinel variable, on_hdd_and_not_all_queues_seeky, if the ++ * device is rotational and not all queues with pending or ++ * in-flight requests are constantly seeky (i.e., there are ++ * active sequential queues, and bfqq might then be mistreated ++ * if it does not enjoy idling because it is random). ++ */ ++ all_queues_seeky = bfq_bfqq_constantly_seeky(bfqq) && ++ bfqd->busy_in_flight_queues == ++ bfqd->const_seeky_busy_in_flight_queues; ++ ++ on_hdd_and_not_all_queues_seeky = ++ !blk_queue_nonrot(bfqd->queue) && !all_queues_seeky; ++ ++ /* ++ * To introduce the second case where idling needs to be ++ * performed to preserve service guarantees, we can note that ++ * allowing the drive to enqueue more than one request at a ++ * time, and hence delegating de facto final scheduling ++ * decisions to the drive's internal scheduler, causes loss of ++ * control on the actual request service order. In particular, ++ * the critical situation is when requests from different ++ * processes happens to be present, at the same time, in the ++ * internal queue(s) of the drive. In such a situation, the ++ * drive, by deciding the service order of the ++ * internally-queued requests, does determine also the actual ++ * throughput distribution among these processes. But the ++ * drive typically has no notion or concern about per-process ++ * throughput distribution, and makes its decisions only on a ++ * per-request basis. Therefore, the service distribution ++ * enforced by the drive's internal scheduler is likely to ++ * coincide with the desired device-throughput distribution ++ * only in a completely symmetric scenario where: ++ * (i) each of these processes must get the same throughput as ++ * the others; ++ * (ii) all these processes have the same I/O pattern ++ (either sequential or random). ++ * In fact, in such a scenario, the drive will tend to treat ++ * the requests of each of these processes in about the same ++ * way as the requests of the others, and thus to provide ++ * each of these processes with about the same throughput ++ * (which is exactly the desired throughput distribution). In ++ * contrast, in any asymmetric scenario, device idling is ++ * certainly needed to guarantee that bfqq receives its ++ * assigned fraction of the device throughput (see [1] for ++ * details). ++ * ++ * We address this issue by controlling, actually, only the ++ * symmetry sub-condition (i), i.e., provided that ++ * sub-condition (i) holds, idling is not performed, ++ * regardless of whether sub-condition (ii) holds. In other ++ * words, only if sub-condition (i) holds, then idling is ++ * allowed, and the device tends to be prevented from queueing ++ * many requests, possibly of several processes. The reason ++ * for not controlling also sub-condition (ii) is that, first, ++ * in the case of an HDD, the asymmetry in terms of types of ++ * I/O patterns is already taken in to account in the above ++ * sentinel variable ++ * on_hdd_and_not_all_queues_seeky. Secondly, in the case of a ++ * flash-based device, we prefer however to privilege ++ * throughput (and idling lowers throughput for this type of ++ * devices), for the following reasons: ++ * 1) differently from HDDs, the service time of random ++ * requests is not orders of magnitudes lower than the service ++ * time of sequential requests; thus, even if processes doing ++ * sequential I/O get a preferential treatment with respect to ++ * others doing random I/O, the consequences are not as ++ * dramatic as with HDDs; ++ * 2) if a process doing random I/O does need strong ++ * throughput guarantees, it is hopefully already being ++ * weight-raised, or the user is likely to have assigned it a ++ * higher weight than the other processes (and thus ++ * sub-condition (i) is likely to be false, which triggers ++ * idling). ++ * ++ * According to the above considerations, the next variable is ++ * true (only) if sub-condition (i) holds. To compute the ++ * value of this variable, we not only use the return value of ++ * the function bfq_symmetric_scenario(), but also check ++ * whether bfqq is being weight-raised, because ++ * bfq_symmetric_scenario() does not take into account also ++ * weight-raised queues (see comments to ++ * bfq_weights_tree_add()). ++ * ++ * As a side note, it is worth considering that the above ++ * device-idling countermeasures may however fail in the ++ * following unlucky scenario: if idling is (correctly) ++ * disabled in a time period during which all symmetry ++ * sub-conditions hold, and hence the device is allowed to ++ * enqueue many requests, but at some later point in time some ++ * sub-condition stops to hold, then it may become impossible ++ * to let requests be served in the desired order until all ++ * the requests already queued in the device have been served. ++ */ ++ asymmetric_scenario = bfqq->wr_coeff > 1 || ++ !bfq_symmetric_scenario(bfqd); ++ ++ /* ++ * Finally, there is a case where maximizing throughput is the ++ * best choice even if it may cause unfairness toward ++ * bfqq. Such a case is when bfqq became active in a burst of ++ * queue activations. Queues that became active during a large ++ * burst benefit only from throughput, as discussed in the ++ * comments to bfq_handle_burst. Thus, if bfqq became active ++ * in a burst and not idling the device maximizes throughput, ++ * then the device must no be idled, because not idling the ++ * device provides bfqq and all other queues in the burst with ++ * maximum benefit. Combining this and the two cases above, we ++ * can now establish when idling is actually needed to ++ * preserve service guarantees. ++ */ ++ idling_needed_for_service_guarantees = ++ (on_hdd_and_not_all_queues_seeky || asymmetric_scenario) && ++ !bfq_bfqq_in_large_burst(bfqq); ++ ++ /* ++ * We have now all the components we need to compute the return ++ * value of the function, which is true only if both the following ++ * conditions hold: ++ * 1) bfqq is sync, because idling make sense only for sync queues; ++ * 2) idling either boosts the throughput (without issues), or ++ * is necessary to preserve service guarantees. ++ */ ++ return bfq_bfqq_sync(bfqq) && ++ (idling_boosts_thr_without_issues || ++ idling_needed_for_service_guarantees); ++} ++ ++/* ++ * If the in-service queue is empty but the function bfq_bfqq_may_idle ++ * returns true, then: ++ * 1) the queue must remain in service and cannot be expired, and ++ * 2) the device must be idled to wait for the possible arrival of a new ++ * request for the queue. ++ * See the comments to the function bfq_bfqq_may_idle for the reasons ++ * why performing device idling is the best choice to boost the throughput ++ * and preserve service guarantees when bfq_bfqq_may_idle itself ++ * returns true. ++ */ ++static bool bfq_bfqq_must_idle(struct bfq_queue *bfqq) ++{ ++ struct bfq_data *bfqd = bfqq->bfqd; ++ ++ return RB_EMPTY_ROOT(&bfqq->sort_list) && bfqd->bfq_slice_idle != 0 && ++ bfq_bfqq_may_idle(bfqq); ++} ++ ++/* ++ * Select a queue for service. If we have a current queue in service, ++ * check whether to continue servicing it, or retrieve and set a new one. ++ */ ++static struct bfq_queue *bfq_select_queue(struct bfq_data *bfqd) ++{ ++ struct bfq_queue *bfqq; ++ struct request *next_rq; ++ enum bfqq_expiration reason = BFQ_BFQQ_BUDGET_TIMEOUT; ++ ++ bfqq = bfqd->in_service_queue; ++ if (!bfqq) ++ goto new_queue; ++ ++ bfq_log_bfqq(bfqd, bfqq, "select_queue: already in-service queue"); ++ ++ if (bfq_may_expire_for_budg_timeout(bfqq) && ++ !timer_pending(&bfqd->idle_slice_timer) && ++ !bfq_bfqq_must_idle(bfqq)) ++ goto expire; ++ ++ next_rq = bfqq->next_rq; ++ /* ++ * If bfqq has requests queued and it has enough budget left to ++ * serve them, keep the queue, otherwise expire it. ++ */ ++ if (next_rq) { ++ if (bfq_serv_to_charge(next_rq, bfqq) > ++ bfq_bfqq_budget_left(bfqq)) { ++ reason = BFQ_BFQQ_BUDGET_EXHAUSTED; ++ goto expire; ++ } else { ++ /* ++ * The idle timer may be pending because we may ++ * not disable disk idling even when a new request ++ * arrives. ++ */ ++ if (timer_pending(&bfqd->idle_slice_timer)) { ++ /* ++ * If we get here: 1) at least a new request ++ * has arrived but we have not disabled the ++ * timer because the request was too small, ++ * 2) then the block layer has unplugged ++ * the device, causing the dispatch to be ++ * invoked. ++ * ++ * Since the device is unplugged, now the ++ * requests are probably large enough to ++ * provide a reasonable throughput. ++ * So we disable idling. ++ */ ++ bfq_clear_bfqq_wait_request(bfqq); ++ del_timer(&bfqd->idle_slice_timer); ++#ifdef CONFIG_BFQ_GROUP_IOSCHED ++ bfqg_stats_update_idle_time(bfqq_group(bfqq)); ++#endif ++ } ++ goto keep_queue; ++ } ++ } ++ ++ /* ++ * No requests pending. However, if the in-service queue is idling ++ * for a new request, or has requests waiting for a completion and ++ * may idle after their completion, then keep it anyway. ++ */ ++ if (timer_pending(&bfqd->idle_slice_timer) || ++ (bfqq->dispatched != 0 && bfq_bfqq_may_idle(bfqq))) { ++ bfqq = NULL; ++ goto keep_queue; ++ } ++ ++ reason = BFQ_BFQQ_NO_MORE_REQUESTS; ++expire: ++ bfq_bfqq_expire(bfqd, bfqq, false, reason); ++new_queue: ++ bfqq = bfq_set_in_service_queue(bfqd); ++ bfq_log(bfqd, "select_queue: new queue %d returned", ++ bfqq ? bfqq->pid : 0); ++keep_queue: ++ return bfqq; ++} ++ ++static void bfq_update_wr_data(struct bfq_data *bfqd, struct bfq_queue *bfqq) ++{ ++ struct bfq_entity *entity = &bfqq->entity; ++ if (bfqq->wr_coeff > 1) { /* queue is being weight-raised */ ++ bfq_log_bfqq(bfqd, bfqq, ++ "raising period dur %u/%u msec, old coeff %u, w %d(%d)", ++ jiffies_to_msecs(jiffies - bfqq->last_wr_start_finish), ++ jiffies_to_msecs(bfqq->wr_cur_max_time), ++ bfqq->wr_coeff, ++ bfqq->entity.weight, bfqq->entity.orig_weight); ++ ++ BUG_ON(bfqq != bfqd->in_service_queue && entity->weight != ++ entity->orig_weight * bfqq->wr_coeff); ++ if (entity->prio_changed) ++ bfq_log_bfqq(bfqd, bfqq, "WARN: pending prio change"); ++ ++ /* ++ * If the queue was activated in a burst, or ++ * too much time has elapsed from the beginning ++ * of this weight-raising period, then end weight ++ * raising. ++ */ ++ if (bfq_bfqq_in_large_burst(bfqq) || ++ time_is_before_jiffies(bfqq->last_wr_start_finish + ++ bfqq->wr_cur_max_time)) { ++ bfqq->last_wr_start_finish = jiffies; ++ bfq_log_bfqq(bfqd, bfqq, ++ "wrais ending at %lu, rais_max_time %u", ++ bfqq->last_wr_start_finish, ++ jiffies_to_msecs(bfqq->wr_cur_max_time)); ++ bfq_bfqq_end_wr(bfqq); ++ } ++ } ++ /* Update weight both if it must be raised and if it must be lowered */ ++ if ((entity->weight > entity->orig_weight) != (bfqq->wr_coeff > 1)) ++ __bfq_entity_update_weight_prio( ++ bfq_entity_service_tree(entity), ++ entity); ++} ++ ++/* ++ * Dispatch one request from bfqq, moving it to the request queue ++ * dispatch list. ++ */ ++static int bfq_dispatch_request(struct bfq_data *bfqd, ++ struct bfq_queue *bfqq) ++{ ++ int dispatched = 0; ++ struct request *rq; ++ unsigned long service_to_charge; ++ ++ BUG_ON(RB_EMPTY_ROOT(&bfqq->sort_list)); ++ ++ /* Follow expired path, else get first next available. */ ++ rq = bfq_check_fifo(bfqq); ++ if (!rq) ++ rq = bfqq->next_rq; ++ service_to_charge = bfq_serv_to_charge(rq, bfqq); ++ ++ if (service_to_charge > bfq_bfqq_budget_left(bfqq)) { ++ /* ++ * This may happen if the next rq is chosen in fifo order ++ * instead of sector order. The budget is properly ++ * dimensioned to be always sufficient to serve the next ++ * request only if it is chosen in sector order. The reason ++ * is that it would be quite inefficient and little useful ++ * to always make sure that the budget is large enough to ++ * serve even the possible next rq in fifo order. ++ * In fact, requests are seldom served in fifo order. ++ * ++ * Expire the queue for budget exhaustion, and make sure ++ * that the next act_budget is enough to serve the next ++ * request, even if it comes from the fifo expired path. ++ */ ++ bfqq->next_rq = rq; ++ /* ++ * Since this dispatch is failed, make sure that ++ * a new one will be performed ++ */ ++ if (!bfqd->rq_in_driver) ++ bfq_schedule_dispatch(bfqd); ++ goto expire; ++ } ++ ++ /* Finally, insert request into driver dispatch list. */ ++ bfq_bfqq_served(bfqq, service_to_charge); ++ bfq_dispatch_insert(bfqd->queue, rq); ++ ++ bfq_update_wr_data(bfqd, bfqq); ++ ++ bfq_log_bfqq(bfqd, bfqq, ++ "dispatched %u sec req (%llu), budg left %d", ++ blk_rq_sectors(rq), ++ (long long unsigned)blk_rq_pos(rq), ++ bfq_bfqq_budget_left(bfqq)); ++ ++ dispatched++; ++ ++ if (!bfqd->in_service_bic) { ++ atomic_long_inc(&RQ_BIC(rq)->icq.ioc->refcount); ++ bfqd->in_service_bic = RQ_BIC(rq); ++ } ++ ++ if (bfqd->busy_queues > 1 && ((!bfq_bfqq_sync(bfqq) && ++ dispatched >= bfqd->bfq_max_budget_async_rq) || ++ bfq_class_idle(bfqq))) ++ goto expire; ++ ++ return dispatched; ++ ++expire: ++ bfq_bfqq_expire(bfqd, bfqq, false, BFQ_BFQQ_BUDGET_EXHAUSTED); ++ return dispatched; ++} ++ ++static int __bfq_forced_dispatch_bfqq(struct bfq_queue *bfqq) ++{ ++ int dispatched = 0; ++ ++ while (bfqq->next_rq) { ++ bfq_dispatch_insert(bfqq->bfqd->queue, bfqq->next_rq); ++ dispatched++; ++ } ++ ++ BUG_ON(!list_empty(&bfqq->fifo)); ++ return dispatched; ++} ++ ++/* ++ * Drain our current requests. ++ * Used for barriers and when switching io schedulers on-the-fly. ++ */ ++static int bfq_forced_dispatch(struct bfq_data *bfqd) ++{ ++ struct bfq_queue *bfqq, *n; ++ struct bfq_service_tree *st; ++ int dispatched = 0; ++ ++ bfqq = bfqd->in_service_queue; ++ if (bfqq) ++ __bfq_bfqq_expire(bfqd, bfqq); ++ ++ /* ++ * Loop through classes, and be careful to leave the scheduler ++ * in a consistent state, as feedback mechanisms and vtime ++ * updates cannot be disabled during the process. ++ */ ++ list_for_each_entry_safe(bfqq, n, &bfqd->active_list, bfqq_list) { ++ st = bfq_entity_service_tree(&bfqq->entity); ++ ++ dispatched += __bfq_forced_dispatch_bfqq(bfqq); ++ bfqq->max_budget = bfq_max_budget(bfqd); ++ ++ bfq_forget_idle(st); ++ } ++ ++ BUG_ON(bfqd->busy_queues != 0); ++ ++ return dispatched; ++} ++ ++static int bfq_dispatch_requests(struct request_queue *q, int force) ++{ ++ struct bfq_data *bfqd = q->elevator->elevator_data; ++ struct bfq_queue *bfqq; ++ int max_dispatch; ++ ++ bfq_log(bfqd, "dispatch requests: %d busy queues", bfqd->busy_queues); ++ if (bfqd->busy_queues == 0) ++ return 0; ++ ++ if (unlikely(force)) ++ return bfq_forced_dispatch(bfqd); ++ ++ bfqq = bfq_select_queue(bfqd); ++ if (!bfqq) ++ return 0; ++ ++ if (bfq_class_idle(bfqq)) ++ max_dispatch = 1; ++ ++ if (!bfq_bfqq_sync(bfqq)) ++ max_dispatch = bfqd->bfq_max_budget_async_rq; ++ ++ if (!bfq_bfqq_sync(bfqq) && bfqq->dispatched >= max_dispatch) { ++ if (bfqd->busy_queues > 1) ++ return 0; ++ if (bfqq->dispatched >= 4 * max_dispatch) ++ return 0; ++ } ++ ++ if (bfqd->sync_flight != 0 && !bfq_bfqq_sync(bfqq)) ++ return 0; ++ ++ bfq_clear_bfqq_wait_request(bfqq); ++ BUG_ON(timer_pending(&bfqd->idle_slice_timer)); ++ ++ if (!bfq_dispatch_request(bfqd, bfqq)) ++ return 0; ++ ++ bfq_log_bfqq(bfqd, bfqq, "dispatched %s request", ++ bfq_bfqq_sync(bfqq) ? "sync" : "async"); ++ ++ return 1; ++} ++ ++/* ++ * Task holds one reference to the queue, dropped when task exits. Each rq ++ * in-flight on this queue also holds a reference, dropped when rq is freed. ++ * ++ * Queue lock must be held here. ++ */ ++static void bfq_put_queue(struct bfq_queue *bfqq) ++{ ++ struct bfq_data *bfqd = bfqq->bfqd; ++#ifdef CONFIG_BFQ_GROUP_IOSCHED ++ struct bfq_group *bfqg = bfqq_group(bfqq); ++#endif ++ ++ BUG_ON(atomic_read(&bfqq->ref) <= 0); ++ ++ bfq_log_bfqq(bfqd, bfqq, "put_queue: %p %d", bfqq, ++ atomic_read(&bfqq->ref)); ++ if (!atomic_dec_and_test(&bfqq->ref)) ++ return; ++ ++ BUG_ON(rb_first(&bfqq->sort_list)); ++ BUG_ON(bfqq->allocated[READ] + bfqq->allocated[WRITE] != 0); ++ BUG_ON(bfqq->entity.tree); ++ BUG_ON(bfq_bfqq_busy(bfqq)); ++ BUG_ON(bfqd->in_service_queue == bfqq); ++ ++ if (bfq_bfqq_sync(bfqq)) ++ /* ++ * The fact that this queue is being destroyed does not ++ * invalidate the fact that this queue may have been ++ * activated during the current burst. As a consequence, ++ * although the queue does not exist anymore, and hence ++ * needs to be removed from the burst list if there, ++ * the burst size has not to be decremented. ++ */ ++ hlist_del_init(&bfqq->burst_list_node); ++ ++ bfq_log_bfqq(bfqd, bfqq, "put_queue: %p freed", bfqq); ++ ++ kmem_cache_free(bfq_pool, bfqq); ++#ifdef CONFIG_BFQ_GROUP_IOSCHED ++ bfqg_put(bfqg); ++#endif ++} ++ ++static void bfq_exit_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq) ++{ ++ if (bfqq == bfqd->in_service_queue) { ++ __bfq_bfqq_expire(bfqd, bfqq); ++ bfq_schedule_dispatch(bfqd); ++ } ++ ++ bfq_log_bfqq(bfqd, bfqq, "exit_bfqq: %p, %d", bfqq, ++ atomic_read(&bfqq->ref)); ++ ++ bfq_put_queue(bfqq); ++} ++ ++static void bfq_init_icq(struct io_cq *icq) ++{ ++ struct bfq_io_cq *bic = icq_to_bic(icq); ++ ++ bic->ttime.last_end_request = jiffies; ++} ++ ++static void bfq_exit_icq(struct io_cq *icq) ++{ ++ struct bfq_io_cq *bic = icq_to_bic(icq); ++ struct bfq_data *bfqd = bic_to_bfqd(bic); ++ ++ if (bic->bfqq[BLK_RW_ASYNC]) { ++ bfq_exit_bfqq(bfqd, bic->bfqq[BLK_RW_ASYNC]); ++ bic->bfqq[BLK_RW_ASYNC] = NULL; ++ } ++ ++ if (bic->bfqq[BLK_RW_SYNC]) { ++ bfq_exit_bfqq(bfqd, bic->bfqq[BLK_RW_SYNC]); ++ bic->bfqq[BLK_RW_SYNC] = NULL; ++ } ++} ++ ++/* ++ * Update the entity prio values; note that the new values will not ++ * be used until the next (re)activation. ++ */ ++static void bfq_set_next_ioprio_data(struct bfq_queue *bfqq, struct bfq_io_cq *bic) ++{ ++ struct task_struct *tsk = current; ++ int ioprio_class; ++ ++ ioprio_class = IOPRIO_PRIO_CLASS(bic->ioprio); ++ switch (ioprio_class) { ++ default: ++ dev_err(bfqq->bfqd->queue->backing_dev_info.dev, ++ "bfq: bad prio class %d\n", ioprio_class); ++ case IOPRIO_CLASS_NONE: ++ /* ++ * No prio set, inherit CPU scheduling settings. ++ */ ++ bfqq->new_ioprio = task_nice_ioprio(tsk); ++ bfqq->new_ioprio_class = task_nice_ioclass(tsk); ++ break; ++ case IOPRIO_CLASS_RT: ++ bfqq->new_ioprio = IOPRIO_PRIO_DATA(bic->ioprio); ++ bfqq->new_ioprio_class = IOPRIO_CLASS_RT; ++ break; ++ case IOPRIO_CLASS_BE: ++ bfqq->new_ioprio = IOPRIO_PRIO_DATA(bic->ioprio); ++ bfqq->new_ioprio_class = IOPRIO_CLASS_BE; ++ break; ++ case IOPRIO_CLASS_IDLE: ++ bfqq->new_ioprio_class = IOPRIO_CLASS_IDLE; ++ bfqq->new_ioprio = 7; ++ bfq_clear_bfqq_idle_window(bfqq); ++ break; ++ } ++ ++ if (bfqq->new_ioprio < 0 || bfqq->new_ioprio >= IOPRIO_BE_NR) { ++ printk(KERN_CRIT "bfq_set_next_ioprio_data: new_ioprio %d\n", ++ bfqq->new_ioprio); ++ BUG(); ++ } ++ ++ bfqq->entity.new_weight = bfq_ioprio_to_weight(bfqq->new_ioprio); ++ bfqq->entity.prio_changed = 1; ++} ++ ++static void bfq_check_ioprio_change(struct bfq_io_cq *bic, struct bio *bio) ++{ ++ struct bfq_data *bfqd; ++ struct bfq_queue *bfqq, *new_bfqq; ++ unsigned long uninitialized_var(flags); ++ int ioprio = bic->icq.ioc->ioprio; ++ ++ bfqd = bfq_get_bfqd_locked(&(bic->icq.q->elevator->elevator_data), ++ &flags); ++ /* ++ * This condition may trigger on a newly created bic, be sure to ++ * drop the lock before returning. ++ */ ++ if (unlikely(!bfqd) || likely(bic->ioprio == ioprio)) ++ goto out; ++ ++ bic->ioprio = ioprio; ++ ++ bfqq = bic->bfqq[BLK_RW_ASYNC]; ++ if (bfqq) { ++ new_bfqq = bfq_get_queue(bfqd, bio, BLK_RW_ASYNC, bic, ++ GFP_ATOMIC); ++ if (new_bfqq) { ++ bic->bfqq[BLK_RW_ASYNC] = new_bfqq; ++ bfq_log_bfqq(bfqd, bfqq, ++ "check_ioprio_change: bfqq %p %d", ++ bfqq, atomic_read(&bfqq->ref)); ++ bfq_put_queue(bfqq); ++ } ++ } ++ ++ bfqq = bic->bfqq[BLK_RW_SYNC]; ++ if (bfqq) ++ bfq_set_next_ioprio_data(bfqq, bic); ++ ++out: ++ bfq_put_bfqd_unlock(bfqd, &flags); ++} ++ ++static void bfq_init_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq, ++ struct bfq_io_cq *bic, pid_t pid, int is_sync) ++{ ++ RB_CLEAR_NODE(&bfqq->entity.rb_node); ++ INIT_LIST_HEAD(&bfqq->fifo); ++ INIT_HLIST_NODE(&bfqq->burst_list_node); ++ ++ atomic_set(&bfqq->ref, 0); ++ bfqq->bfqd = bfqd; ++ ++ if (bic) ++ bfq_set_next_ioprio_data(bfqq, bic); ++ ++ if (is_sync) { ++ if (!bfq_class_idle(bfqq)) ++ bfq_mark_bfqq_idle_window(bfqq); ++ bfq_mark_bfqq_sync(bfqq); ++ } else ++ bfq_clear_bfqq_sync(bfqq); ++ bfq_mark_bfqq_IO_bound(bfqq); ++ ++ /* Tentative initial value to trade off between thr and lat */ ++ bfqq->max_budget = (2 * bfq_max_budget(bfqd)) / 3; ++ bfqq->pid = pid; ++ ++ bfqq->wr_coeff = 1; ++ bfqq->last_wr_start_finish = 0; ++ /* ++ * Set to the value for which bfqq will not be deemed as ++ * soft rt when it becomes backlogged. ++ */ ++ bfqq->soft_rt_next_start = bfq_infinity_from_now(jiffies); ++} ++ ++static struct bfq_queue *bfq_find_alloc_queue(struct bfq_data *bfqd, ++ struct bio *bio, int is_sync, ++ struct bfq_io_cq *bic, ++ gfp_t gfp_mask) ++{ ++ struct bfq_group *bfqg; ++ struct bfq_queue *bfqq, *new_bfqq = NULL; ++ struct blkcg *blkcg; ++ ++retry: ++ rcu_read_lock(); ++ ++ blkcg = bio_blkcg(bio); ++ bfqg = bfq_find_alloc_group(bfqd, blkcg); ++ /* bic always exists here */ ++ bfqq = bic_to_bfqq(bic, is_sync); ++ ++ /* ++ * Always try a new alloc if we fall back to the OOM bfqq ++ * originally, since it should just be a temporary situation. ++ */ ++ if (!bfqq || bfqq == &bfqd->oom_bfqq) { ++ bfqq = NULL; ++ if (new_bfqq) { ++ bfqq = new_bfqq; ++ new_bfqq = NULL; ++ } else if (gfpflags_allow_blocking(gfp_mask)) { ++ rcu_read_unlock(); ++ spin_unlock_irq(bfqd->queue->queue_lock); ++ new_bfqq = kmem_cache_alloc_node(bfq_pool, ++ gfp_mask | __GFP_ZERO, ++ bfqd->queue->node); ++ spin_lock_irq(bfqd->queue->queue_lock); ++ if (new_bfqq) ++ goto retry; ++ } else { ++ bfqq = kmem_cache_alloc_node(bfq_pool, ++ gfp_mask | __GFP_ZERO, ++ bfqd->queue->node); ++ } ++ ++ if (bfqq) { ++ bfq_init_bfqq(bfqd, bfqq, bic, current->pid, ++ is_sync); ++ bfq_init_entity(&bfqq->entity, bfqg); ++ bfq_log_bfqq(bfqd, bfqq, "allocated"); ++ } else { ++ bfqq = &bfqd->oom_bfqq; ++ bfq_log_bfqq(bfqd, bfqq, "using oom bfqq"); ++ } ++ } ++ ++ if (new_bfqq) ++ kmem_cache_free(bfq_pool, new_bfqq); ++ ++ rcu_read_unlock(); ++ ++ return bfqq; ++} ++ ++static struct bfq_queue **bfq_async_queue_prio(struct bfq_data *bfqd, ++ struct bfq_group *bfqg, ++ int ioprio_class, int ioprio) ++{ ++ switch (ioprio_class) { ++ case IOPRIO_CLASS_RT: ++ return &bfqg->async_bfqq[0][ioprio]; ++ case IOPRIO_CLASS_NONE: ++ ioprio = IOPRIO_NORM; ++ /* fall through */ ++ case IOPRIO_CLASS_BE: ++ return &bfqg->async_bfqq[1][ioprio]; ++ case IOPRIO_CLASS_IDLE: ++ return &bfqg->async_idle_bfqq; ++ default: ++ BUG(); ++ } ++} ++ ++static struct bfq_queue *bfq_get_queue(struct bfq_data *bfqd, ++ struct bio *bio, int is_sync, ++ struct bfq_io_cq *bic, gfp_t gfp_mask) ++{ ++ const int ioprio = IOPRIO_PRIO_DATA(bic->ioprio); ++ const int ioprio_class = IOPRIO_PRIO_CLASS(bic->ioprio); ++ struct bfq_queue **async_bfqq = NULL; ++ struct bfq_queue *bfqq = NULL; ++ ++ if (!is_sync) { ++ struct blkcg *blkcg; ++ struct bfq_group *bfqg; ++ ++ rcu_read_lock(); ++ blkcg = bio_blkcg(bio); ++ rcu_read_unlock(); ++ bfqg = bfq_find_alloc_group(bfqd, blkcg); ++ async_bfqq = bfq_async_queue_prio(bfqd, bfqg, ioprio_class, ++ ioprio); ++ bfqq = *async_bfqq; ++ } ++ ++ if (!bfqq) ++ bfqq = bfq_find_alloc_queue(bfqd, bio, is_sync, bic, gfp_mask); ++ ++ /* ++ * Pin the queue now that it's allocated, scheduler exit will ++ * prune it. ++ */ ++ if (!is_sync && !(*async_bfqq)) { ++ atomic_inc(&bfqq->ref); ++ bfq_log_bfqq(bfqd, bfqq, "get_queue, bfqq not in async: %p, %d", ++ bfqq, atomic_read(&bfqq->ref)); ++ *async_bfqq = bfqq; ++ } ++ ++ atomic_inc(&bfqq->ref); ++ bfq_log_bfqq(bfqd, bfqq, "get_queue, at end: %p, %d", bfqq, ++ atomic_read(&bfqq->ref)); ++ return bfqq; ++} ++ ++static void bfq_update_io_thinktime(struct bfq_data *bfqd, ++ struct bfq_io_cq *bic) ++{ ++ unsigned long elapsed = jiffies - bic->ttime.last_end_request; ++ unsigned long ttime = min(elapsed, 2UL * bfqd->bfq_slice_idle); ++ ++ bic->ttime.ttime_samples = (7*bic->ttime.ttime_samples + 256) / 8; ++ bic->ttime.ttime_total = (7*bic->ttime.ttime_total + 256*ttime) / 8; ++ bic->ttime.ttime_mean = (bic->ttime.ttime_total + 128) / ++ bic->ttime.ttime_samples; ++} ++ ++static void bfq_update_io_seektime(struct bfq_data *bfqd, ++ struct bfq_queue *bfqq, ++ struct request *rq) ++{ ++ sector_t sdist; ++ u64 total; ++ ++ if (bfqq->last_request_pos < blk_rq_pos(rq)) ++ sdist = blk_rq_pos(rq) - bfqq->last_request_pos; ++ else ++ sdist = bfqq->last_request_pos - blk_rq_pos(rq); ++ ++ /* ++ * Don't allow the seek distance to get too large from the ++ * odd fragment, pagein, etc. ++ */ ++ if (bfqq->seek_samples == 0) /* first request, not really a seek */ ++ sdist = 0; ++ else if (bfqq->seek_samples <= 60) /* second & third seek */ ++ sdist = min(sdist, (bfqq->seek_mean * 4) + 2*1024*1024); ++ else ++ sdist = min(sdist, (bfqq->seek_mean * 4) + 2*1024*64); ++ ++ bfqq->seek_samples = (7*bfqq->seek_samples + 256) / 8; ++ bfqq->seek_total = (7*bfqq->seek_total + (u64)256*sdist) / 8; ++ total = bfqq->seek_total + (bfqq->seek_samples/2); ++ do_div(total, bfqq->seek_samples); ++ bfqq->seek_mean = (sector_t)total; ++ ++ bfq_log_bfqq(bfqd, bfqq, "dist=%llu mean=%llu", (u64)sdist, ++ (u64)bfqq->seek_mean); ++} ++ ++/* ++ * Disable idle window if the process thinks too long or seeks so much that ++ * it doesn't matter. ++ */ ++static void bfq_update_idle_window(struct bfq_data *bfqd, ++ struct bfq_queue *bfqq, ++ struct bfq_io_cq *bic) ++{ ++ int enable_idle; ++ ++ /* Don't idle for async or idle io prio class. */ ++ if (!bfq_bfqq_sync(bfqq) || bfq_class_idle(bfqq)) ++ return; ++ ++ enable_idle = bfq_bfqq_idle_window(bfqq); ++ ++ if (atomic_read(&bic->icq.ioc->active_ref) == 0 || ++ bfqd->bfq_slice_idle == 0 || ++ (bfqd->hw_tag && BFQQ_SEEKY(bfqq) && ++ bfqq->wr_coeff == 1)) ++ enable_idle = 0; ++ else if (bfq_sample_valid(bic->ttime.ttime_samples)) { ++ if (bic->ttime.ttime_mean > bfqd->bfq_slice_idle && ++ bfqq->wr_coeff == 1) ++ enable_idle = 0; ++ else ++ enable_idle = 1; ++ } ++ bfq_log_bfqq(bfqd, bfqq, "update_idle_window: enable_idle %d", ++ enable_idle); ++ ++ if (enable_idle) ++ bfq_mark_bfqq_idle_window(bfqq); ++ else ++ bfq_clear_bfqq_idle_window(bfqq); ++} ++ ++/* ++ * Called when a new fs request (rq) is added to bfqq. Check if there's ++ * something we should do about it. ++ */ ++static void bfq_rq_enqueued(struct bfq_data *bfqd, struct bfq_queue *bfqq, ++ struct request *rq) ++{ ++ struct bfq_io_cq *bic = RQ_BIC(rq); ++ ++ if (rq->cmd_flags & REQ_META) ++ bfqq->meta_pending++; ++ ++ bfq_update_io_thinktime(bfqd, bic); ++ bfq_update_io_seektime(bfqd, bfqq, rq); ++ if (!BFQQ_SEEKY(bfqq) && bfq_bfqq_constantly_seeky(bfqq)) { ++ bfq_clear_bfqq_constantly_seeky(bfqq); ++ if (!blk_queue_nonrot(bfqd->queue)) { ++ BUG_ON(!bfqd->const_seeky_busy_in_flight_queues); ++ bfqd->const_seeky_busy_in_flight_queues--; ++ } ++ } ++ if (bfqq->entity.service > bfq_max_budget(bfqd) / 8 || ++ !BFQQ_SEEKY(bfqq)) ++ bfq_update_idle_window(bfqd, bfqq, bic); ++ ++ bfq_log_bfqq(bfqd, bfqq, ++ "rq_enqueued: idle_window=%d (seeky %d, mean %llu)", ++ bfq_bfqq_idle_window(bfqq), BFQQ_SEEKY(bfqq), ++ (long long unsigned)bfqq->seek_mean); ++ ++ bfqq->last_request_pos = blk_rq_pos(rq) + blk_rq_sectors(rq); ++ ++ if (bfqq == bfqd->in_service_queue && bfq_bfqq_wait_request(bfqq)) { ++ bool small_req = bfqq->queued[rq_is_sync(rq)] == 1 && ++ blk_rq_sectors(rq) < 32; ++ bool budget_timeout = bfq_bfqq_budget_timeout(bfqq); ++ ++ /* ++ * There is just this request queued: if the request ++ * is small and the queue is not to be expired, then ++ * just exit. ++ * ++ * In this way, if the disk is being idled to wait for ++ * a new request from the in-service queue, we avoid ++ * unplugging the device and committing the disk to serve ++ * just a small request. On the contrary, we wait for ++ * the block layer to decide when to unplug the device: ++ * hopefully, new requests will be merged to this one ++ * quickly, then the device will be unplugged and ++ * larger requests will be dispatched. ++ */ ++ if (small_req && !budget_timeout) ++ return; ++ ++ /* ++ * A large enough request arrived, or the queue is to ++ * be expired: in both cases disk idling is to be ++ * stopped, so clear wait_request flag and reset ++ * timer. ++ */ ++ bfq_clear_bfqq_wait_request(bfqq); ++ del_timer(&bfqd->idle_slice_timer); ++#ifdef CONFIG_BFQ_GROUP_IOSCHED ++ bfqg_stats_update_idle_time(bfqq_group(bfqq)); ++#endif ++ ++ /* ++ * The queue is not empty, because a new request just ++ * arrived. Hence we can safely expire the queue, in ++ * case of budget timeout, without risking that the ++ * timestamps of the queue are not updated correctly. ++ * See [1] for more details. ++ */ ++ if (budget_timeout) ++ bfq_bfqq_expire(bfqd, bfqq, false, ++ BFQ_BFQQ_BUDGET_TIMEOUT); ++ ++ /* ++ * Let the request rip immediately, or let a new queue be ++ * selected if bfqq has just been expired. ++ */ ++ __blk_run_queue(bfqd->queue); ++ } ++} ++ ++static void bfq_insert_request(struct request_queue *q, struct request *rq) ++{ ++ struct bfq_data *bfqd = q->elevator->elevator_data; ++ struct bfq_queue *bfqq = RQ_BFQQ(rq); ++ ++ assert_spin_locked(bfqd->queue->queue_lock); ++ ++ bfq_add_request(rq); ++ ++ rq->fifo_time = jiffies + bfqd->bfq_fifo_expire[rq_is_sync(rq)]; ++ list_add_tail(&rq->queuelist, &bfqq->fifo); ++ ++ bfq_rq_enqueued(bfqd, bfqq, rq); ++} ++ ++static void bfq_update_hw_tag(struct bfq_data *bfqd) ++{ ++ bfqd->max_rq_in_driver = max(bfqd->max_rq_in_driver, ++ bfqd->rq_in_driver); ++ ++ if (bfqd->hw_tag == 1) ++ return; ++ ++ /* ++ * This sample is valid if the number of outstanding requests ++ * is large enough to allow a queueing behavior. Note that the ++ * sum is not exact, as it's not taking into account deactivated ++ * requests. ++ */ ++ if (bfqd->rq_in_driver + bfqd->queued < BFQ_HW_QUEUE_THRESHOLD) ++ return; ++ ++ if (bfqd->hw_tag_samples++ < BFQ_HW_QUEUE_SAMPLES) ++ return; ++ ++ bfqd->hw_tag = bfqd->max_rq_in_driver > BFQ_HW_QUEUE_THRESHOLD; ++ bfqd->max_rq_in_driver = 0; ++ bfqd->hw_tag_samples = 0; ++} ++ ++static void bfq_completed_request(struct request_queue *q, struct request *rq) ++{ ++ struct bfq_queue *bfqq = RQ_BFQQ(rq); ++ struct bfq_data *bfqd = bfqq->bfqd; ++ bool sync = bfq_bfqq_sync(bfqq); ++ ++ bfq_log_bfqq(bfqd, bfqq, "completed one req with %u sects left (%d)", ++ blk_rq_sectors(rq), sync); ++ ++ bfq_update_hw_tag(bfqd); ++ ++ BUG_ON(!bfqd->rq_in_driver); ++ BUG_ON(!bfqq->dispatched); ++ bfqd->rq_in_driver--; ++ bfqq->dispatched--; ++#ifdef CONFIG_BFQ_GROUP_IOSCHED ++ bfqg_stats_update_completion(bfqq_group(bfqq), ++ rq_start_time_ns(rq), ++ rq_io_start_time_ns(rq), rq->cmd_flags); ++#endif ++ ++ if (!bfqq->dispatched && !bfq_bfqq_busy(bfqq)) { ++ bfq_weights_tree_remove(bfqd, &bfqq->entity, ++ &bfqd->queue_weights_tree); ++ if (!blk_queue_nonrot(bfqd->queue)) { ++ BUG_ON(!bfqd->busy_in_flight_queues); ++ bfqd->busy_in_flight_queues--; ++ if (bfq_bfqq_constantly_seeky(bfqq)) { ++ BUG_ON(!bfqd-> ++ const_seeky_busy_in_flight_queues); ++ bfqd->const_seeky_busy_in_flight_queues--; ++ } ++ } ++ } ++ ++ if (sync) { ++ bfqd->sync_flight--; ++ RQ_BIC(rq)->ttime.last_end_request = jiffies; ++ } ++ ++ /* ++ * If we are waiting to discover whether the request pattern of the ++ * task associated with the queue is actually isochronous, and ++ * both requisites for this condition to hold are satisfied, then ++ * compute soft_rt_next_start (see the comments to the function ++ * bfq_bfqq_softrt_next_start()). ++ */ ++ if (bfq_bfqq_softrt_update(bfqq) && bfqq->dispatched == 0 && ++ RB_EMPTY_ROOT(&bfqq->sort_list)) ++ bfqq->soft_rt_next_start = ++ bfq_bfqq_softrt_next_start(bfqd, bfqq); ++ ++ /* ++ * If this is the in-service queue, check if it needs to be expired, ++ * or if we want to idle in case it has no pending requests. ++ */ ++ if (bfqd->in_service_queue == bfqq) { ++ if (bfq_bfqq_budget_new(bfqq)) ++ bfq_set_budget_timeout(bfqd); ++ ++ if (bfq_bfqq_must_idle(bfqq)) { ++ bfq_arm_slice_timer(bfqd); ++ goto out; ++ } else if (bfq_may_expire_for_budg_timeout(bfqq)) ++ bfq_bfqq_expire(bfqd, bfqq, false, ++ BFQ_BFQQ_BUDGET_TIMEOUT); ++ else if (RB_EMPTY_ROOT(&bfqq->sort_list) && ++ (bfqq->dispatched == 0 || ++ !bfq_bfqq_may_idle(bfqq))) ++ bfq_bfqq_expire(bfqd, bfqq, false, ++ BFQ_BFQQ_NO_MORE_REQUESTS); ++ } ++ ++ if (!bfqd->rq_in_driver) ++ bfq_schedule_dispatch(bfqd); ++ ++out: ++ return; ++} ++ ++static int __bfq_may_queue(struct bfq_queue *bfqq) ++{ ++ if (bfq_bfqq_wait_request(bfqq) && bfq_bfqq_must_alloc(bfqq)) { ++ bfq_clear_bfqq_must_alloc(bfqq); ++ return ELV_MQUEUE_MUST; ++ } ++ ++ return ELV_MQUEUE_MAY; ++} ++ ++static int bfq_may_queue(struct request_queue *q, int rw) ++{ ++ struct bfq_data *bfqd = q->elevator->elevator_data; ++ struct task_struct *tsk = current; ++ struct bfq_io_cq *bic; ++ struct bfq_queue *bfqq; ++ ++ /* ++ * Don't force setup of a queue from here, as a call to may_queue ++ * does not necessarily imply that a request actually will be ++ * queued. So just lookup a possibly existing queue, or return ++ * 'may queue' if that fails. ++ */ ++ bic = bfq_bic_lookup(bfqd, tsk->io_context); ++ if (!bic) ++ return ELV_MQUEUE_MAY; ++ ++ bfqq = bic_to_bfqq(bic, rw_is_sync(rw)); ++ if (bfqq) ++ return __bfq_may_queue(bfqq); ++ ++ return ELV_MQUEUE_MAY; ++} ++ ++/* ++ * Queue lock held here. ++ */ ++static void bfq_put_request(struct request *rq) ++{ ++ struct bfq_queue *bfqq = RQ_BFQQ(rq); ++ ++ if (bfqq) { ++ const int rw = rq_data_dir(rq); ++ ++ BUG_ON(!bfqq->allocated[rw]); ++ bfqq->allocated[rw]--; ++ ++ rq->elv.priv[0] = NULL; ++ rq->elv.priv[1] = NULL; ++ ++ bfq_log_bfqq(bfqq->bfqd, bfqq, "put_request %p, %d", ++ bfqq, atomic_read(&bfqq->ref)); ++ bfq_put_queue(bfqq); ++ } ++} ++ ++/* ++ * Allocate bfq data structures associated with this request. ++ */ ++static int bfq_set_request(struct request_queue *q, struct request *rq, ++ struct bio *bio, gfp_t gfp_mask) ++{ ++ struct bfq_data *bfqd = q->elevator->elevator_data; ++ struct bfq_io_cq *bic = icq_to_bic(rq->elv.icq); ++ const int rw = rq_data_dir(rq); ++ const int is_sync = rq_is_sync(rq); ++ struct bfq_queue *bfqq; ++ unsigned long flags; ++ ++ might_sleep_if(gfpflags_allow_blocking(gfp_mask)); ++ ++ bfq_check_ioprio_change(bic, bio); ++ ++ spin_lock_irqsave(q->queue_lock, flags); ++ ++ if (!bic) ++ goto queue_fail; ++ ++ bfq_bic_update_cgroup(bic, bio); ++ ++ bfqq = bic_to_bfqq(bic, is_sync); ++ if (!bfqq || bfqq == &bfqd->oom_bfqq) { ++ bfqq = bfq_get_queue(bfqd, bio, is_sync, bic, gfp_mask); ++ bic_set_bfqq(bic, bfqq, is_sync); ++ if (is_sync) { ++ if (bfqd->large_burst) ++ bfq_mark_bfqq_in_large_burst(bfqq); ++ else ++ bfq_clear_bfqq_in_large_burst(bfqq); ++ } ++ } ++ ++ bfqq->allocated[rw]++; ++ atomic_inc(&bfqq->ref); ++ bfq_log_bfqq(bfqd, bfqq, "set_request: bfqq %p, %d", bfqq, ++ atomic_read(&bfqq->ref)); ++ ++ rq->elv.priv[0] = bic; ++ rq->elv.priv[1] = bfqq; ++ ++ spin_unlock_irqrestore(q->queue_lock, flags); ++ ++ return 0; ++ ++queue_fail: ++ bfq_schedule_dispatch(bfqd); ++ spin_unlock_irqrestore(q->queue_lock, flags); ++ ++ return 1; ++} ++ ++static void bfq_kick_queue(struct work_struct *work) ++{ ++ struct bfq_data *bfqd = ++ container_of(work, struct bfq_data, unplug_work); ++ struct request_queue *q = bfqd->queue; ++ ++ spin_lock_irq(q->queue_lock); ++ __blk_run_queue(q); ++ spin_unlock_irq(q->queue_lock); ++} ++ ++/* ++ * Handler of the expiration of the timer running if the in-service queue ++ * is idling inside its time slice. ++ */ ++static void bfq_idle_slice_timer(unsigned long data) ++{ ++ struct bfq_data *bfqd = (struct bfq_data *)data; ++ struct bfq_queue *bfqq; ++ unsigned long flags; ++ enum bfqq_expiration reason; ++ ++ spin_lock_irqsave(bfqd->queue->queue_lock, flags); ++ ++ bfqq = bfqd->in_service_queue; ++ /* ++ * Theoretical race here: the in-service queue can be NULL or ++ * different from the queue that was idling if the timer handler ++ * spins on the queue_lock and a new request arrives for the ++ * current queue and there is a full dispatch cycle that changes ++ * the in-service queue. This can hardly happen, but in the worst ++ * case we just expire a queue too early. ++ */ ++ if (bfqq) { ++ bfq_log_bfqq(bfqd, bfqq, "slice_timer expired"); ++ if (bfq_bfqq_budget_timeout(bfqq)) ++ /* ++ * Also here the queue can be safely expired ++ * for budget timeout without wasting ++ * guarantees ++ */ ++ reason = BFQ_BFQQ_BUDGET_TIMEOUT; ++ else if (bfqq->queued[0] == 0 && bfqq->queued[1] == 0) ++ /* ++ * The queue may not be empty upon timer expiration, ++ * because we may not disable the timer when the ++ * first request of the in-service queue arrives ++ * during disk idling. ++ */ ++ reason = BFQ_BFQQ_TOO_IDLE; ++ else ++ goto schedule_dispatch; ++ ++ bfq_bfqq_expire(bfqd, bfqq, true, reason); ++ } ++ ++schedule_dispatch: ++ bfq_schedule_dispatch(bfqd); ++ ++ spin_unlock_irqrestore(bfqd->queue->queue_lock, flags); ++} ++ ++static void bfq_shutdown_timer_wq(struct bfq_data *bfqd) ++{ ++ del_timer_sync(&bfqd->idle_slice_timer); ++ cancel_work_sync(&bfqd->unplug_work); ++} ++ ++static void __bfq_put_async_bfqq(struct bfq_data *bfqd, ++ struct bfq_queue **bfqq_ptr) ++{ ++ struct bfq_group *root_group = bfqd->root_group; ++ struct bfq_queue *bfqq = *bfqq_ptr; ++ ++ bfq_log(bfqd, "put_async_bfqq: %p", bfqq); ++ if (bfqq) { ++ bfq_bfqq_move(bfqd, bfqq, &bfqq->entity, root_group); ++ bfq_log_bfqq(bfqd, bfqq, "put_async_bfqq: putting %p, %d", ++ bfqq, atomic_read(&bfqq->ref)); ++ bfq_put_queue(bfqq); ++ *bfqq_ptr = NULL; ++ } ++} ++ ++/* ++ * Release all the bfqg references to its async queues. If we are ++ * deallocating the group these queues may still contain requests, so ++ * we reparent them to the root cgroup (i.e., the only one that will ++ * exist for sure until all the requests on a device are gone). ++ */ ++static void bfq_put_async_queues(struct bfq_data *bfqd, struct bfq_group *bfqg) ++{ ++ int i, j; ++ ++ for (i = 0; i < 2; i++) ++ for (j = 0; j < IOPRIO_BE_NR; j++) ++ __bfq_put_async_bfqq(bfqd, &bfqg->async_bfqq[i][j]); ++ ++ __bfq_put_async_bfqq(bfqd, &bfqg->async_idle_bfqq); ++} ++ ++static void bfq_exit_queue(struct elevator_queue *e) ++{ ++ struct bfq_data *bfqd = e->elevator_data; ++ struct request_queue *q = bfqd->queue; ++ struct bfq_queue *bfqq, *n; ++ ++ bfq_shutdown_timer_wq(bfqd); ++ ++ spin_lock_irq(q->queue_lock); ++ ++ BUG_ON(bfqd->in_service_queue); ++ list_for_each_entry_safe(bfqq, n, &bfqd->idle_list, bfqq_list) ++ bfq_deactivate_bfqq(bfqd, bfqq, 0); ++ ++ bfq_disconnect_groups(bfqd); ++ spin_unlock_irq(q->queue_lock); ++ ++ bfq_shutdown_timer_wq(bfqd); ++ ++ synchronize_rcu(); ++ ++ BUG_ON(timer_pending(&bfqd->idle_slice_timer)); ++ ++#ifdef CONFIG_BFQ_GROUP_IOSCHED ++ blkcg_deactivate_policy(q, &blkcg_policy_bfq); ++#endif ++ ++ kfree(bfqd); ++} ++ ++static void bfq_init_root_group(struct bfq_group *root_group, ++ struct bfq_data *bfqd) ++{ ++ int i; ++ ++#ifdef CONFIG_BFQ_GROUP_IOSCHED ++ root_group->entity.parent = NULL; ++ root_group->my_entity = NULL; ++ root_group->bfqd = bfqd; ++#endif ++ for (i = 0; i < BFQ_IOPRIO_CLASSES; i++) ++ root_group->sched_data.service_tree[i] = BFQ_SERVICE_TREE_INIT; ++} ++ ++static int bfq_init_queue(struct request_queue *q, struct elevator_type *e) ++{ ++ struct bfq_data *bfqd; ++ struct elevator_queue *eq; ++ ++ eq = elevator_alloc(q, e); ++ if (!eq) ++ return -ENOMEM; ++ ++ bfqd = kzalloc_node(sizeof(*bfqd), GFP_KERNEL, q->node); ++ if (!bfqd) { ++ kobject_put(&eq->kobj); ++ return -ENOMEM; ++ } ++ eq->elevator_data = bfqd; ++ ++ /* ++ * Our fallback bfqq if bfq_find_alloc_queue() runs into OOM issues. ++ * Grab a permanent reference to it, so that the normal code flow ++ * will not attempt to free it. ++ */ ++ bfq_init_bfqq(bfqd, &bfqd->oom_bfqq, NULL, 1, 0); ++ atomic_inc(&bfqd->oom_bfqq.ref); ++ bfqd->oom_bfqq.new_ioprio = BFQ_DEFAULT_QUEUE_IOPRIO; ++ bfqd->oom_bfqq.new_ioprio_class = IOPRIO_CLASS_BE; ++ bfqd->oom_bfqq.entity.new_weight = ++ bfq_ioprio_to_weight(bfqd->oom_bfqq.new_ioprio); ++ /* ++ * Trigger weight initialization, according to ioprio, at the ++ * oom_bfqq's first activation. The oom_bfqq's ioprio and ioprio ++ * class won't be changed any more. ++ */ ++ bfqd->oom_bfqq.entity.prio_changed = 1; ++ ++ bfqd->queue = q; ++ ++ spin_lock_irq(q->queue_lock); ++ q->elevator = eq; ++ spin_unlock_irq(q->queue_lock); ++ ++ bfqd->root_group = bfq_create_group_hierarchy(bfqd, q->node); ++ if (!bfqd->root_group) ++ goto out_free; ++ bfq_init_root_group(bfqd->root_group, bfqd); ++ bfq_init_entity(&bfqd->oom_bfqq.entity, bfqd->root_group); ++#ifdef CONFIG_BFQ_GROUP_IOSCHED ++ bfqd->active_numerous_groups = 0; ++#endif ++ ++ init_timer(&bfqd->idle_slice_timer); ++ bfqd->idle_slice_timer.function = bfq_idle_slice_timer; ++ bfqd->idle_slice_timer.data = (unsigned long)bfqd; ++ ++ bfqd->queue_weights_tree = RB_ROOT; ++ bfqd->group_weights_tree = RB_ROOT; ++ ++ INIT_WORK(&bfqd->unplug_work, bfq_kick_queue); ++ ++ INIT_LIST_HEAD(&bfqd->active_list); ++ INIT_LIST_HEAD(&bfqd->idle_list); ++ INIT_HLIST_HEAD(&bfqd->burst_list); ++ ++ bfqd->hw_tag = -1; ++ ++ bfqd->bfq_max_budget = bfq_default_max_budget; ++ ++ bfqd->bfq_fifo_expire[0] = bfq_fifo_expire[0]; ++ bfqd->bfq_fifo_expire[1] = bfq_fifo_expire[1]; ++ bfqd->bfq_back_max = bfq_back_max; ++ bfqd->bfq_back_penalty = bfq_back_penalty; ++ bfqd->bfq_slice_idle = bfq_slice_idle; ++ bfqd->bfq_class_idle_last_service = 0; ++ bfqd->bfq_max_budget_async_rq = bfq_max_budget_async_rq; ++ bfqd->bfq_timeout[BLK_RW_ASYNC] = bfq_timeout_async; ++ bfqd->bfq_timeout[BLK_RW_SYNC] = bfq_timeout_sync; ++ ++ bfqd->bfq_requests_within_timer = 120; ++ ++ bfqd->bfq_large_burst_thresh = 11; ++ bfqd->bfq_burst_interval = msecs_to_jiffies(500); ++ ++ bfqd->low_latency = true; ++ ++ bfqd->bfq_wr_coeff = 20; ++ bfqd->bfq_wr_rt_max_time = msecs_to_jiffies(300); ++ bfqd->bfq_wr_max_time = 0; ++ bfqd->bfq_wr_min_idle_time = msecs_to_jiffies(2000); ++ bfqd->bfq_wr_min_inter_arr_async = msecs_to_jiffies(500); ++ bfqd->bfq_wr_max_softrt_rate = 7000; /* ++ * Approximate rate required ++ * to playback or record a ++ * high-definition compressed ++ * video. ++ */ ++ bfqd->wr_busy_queues = 0; ++ bfqd->busy_in_flight_queues = 0; ++ bfqd->const_seeky_busy_in_flight_queues = 0; ++ ++ /* ++ * Begin by assuming, optimistically, that the device peak rate is ++ * equal to the highest reference rate. ++ */ ++ bfqd->RT_prod = R_fast[blk_queue_nonrot(bfqd->queue)] * ++ T_fast[blk_queue_nonrot(bfqd->queue)]; ++ bfqd->peak_rate = R_fast[blk_queue_nonrot(bfqd->queue)]; ++ bfqd->device_speed = BFQ_BFQD_FAST; ++ ++ return 0; ++ ++out_free: ++ kfree(bfqd); ++ kobject_put(&eq->kobj); ++ return -ENOMEM; ++} ++ ++static void bfq_slab_kill(void) ++{ ++ if (bfq_pool) ++ kmem_cache_destroy(bfq_pool); ++} ++ ++static int __init bfq_slab_setup(void) ++{ ++ bfq_pool = KMEM_CACHE(bfq_queue, 0); ++ if (!bfq_pool) ++ return -ENOMEM; ++ return 0; ++} ++ ++static ssize_t bfq_var_show(unsigned int var, char *page) ++{ ++ return sprintf(page, "%d\n", var); ++} ++ ++static ssize_t bfq_var_store(unsigned long *var, const char *page, ++ size_t count) ++{ ++ unsigned long new_val; ++ int ret = kstrtoul(page, 10, &new_val); ++ ++ if (ret == 0) ++ *var = new_val; ++ ++ return count; ++} ++ ++static ssize_t bfq_wr_max_time_show(struct elevator_queue *e, char *page) ++{ ++ struct bfq_data *bfqd = e->elevator_data; ++ return sprintf(page, "%d\n", bfqd->bfq_wr_max_time > 0 ? ++ jiffies_to_msecs(bfqd->bfq_wr_max_time) : ++ jiffies_to_msecs(bfq_wr_duration(bfqd))); ++} ++ ++static ssize_t bfq_weights_show(struct elevator_queue *e, char *page) ++{ ++ struct bfq_queue *bfqq; ++ struct bfq_data *bfqd = e->elevator_data; ++ ssize_t num_char = 0; ++ ++ num_char += sprintf(page + num_char, "Tot reqs queued %d\n\n", ++ bfqd->queued); ++ ++ spin_lock_irq(bfqd->queue->queue_lock); ++ ++ num_char += sprintf(page + num_char, "Active:\n"); ++ list_for_each_entry(bfqq, &bfqd->active_list, bfqq_list) { ++ num_char += sprintf(page + num_char, ++ "pid%d: weight %hu, nr_queued %d %d, dur %d/%u\n", ++ bfqq->pid, ++ bfqq->entity.weight, ++ bfqq->queued[0], ++ bfqq->queued[1], ++ jiffies_to_msecs(jiffies - bfqq->last_wr_start_finish), ++ jiffies_to_msecs(bfqq->wr_cur_max_time)); ++ } ++ ++ num_char += sprintf(page + num_char, "Idle:\n"); ++ list_for_each_entry(bfqq, &bfqd->idle_list, bfqq_list) { ++ num_char += sprintf(page + num_char, ++ "pid%d: weight %hu, dur %d/%u\n", ++ bfqq->pid, ++ bfqq->entity.weight, ++ jiffies_to_msecs(jiffies - ++ bfqq->last_wr_start_finish), ++ jiffies_to_msecs(bfqq->wr_cur_max_time)); ++ } ++ ++ spin_unlock_irq(bfqd->queue->queue_lock); ++ ++ return num_char; ++} ++ ++#define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \ ++static ssize_t __FUNC(struct elevator_queue *e, char *page) \ ++{ \ ++ struct bfq_data *bfqd = e->elevator_data; \ ++ unsigned int __data = __VAR; \ ++ if (__CONV) \ ++ __data = jiffies_to_msecs(__data); \ ++ return bfq_var_show(__data, (page)); \ ++} ++SHOW_FUNCTION(bfq_fifo_expire_sync_show, bfqd->bfq_fifo_expire[1], 1); ++SHOW_FUNCTION(bfq_fifo_expire_async_show, bfqd->bfq_fifo_expire[0], 1); ++SHOW_FUNCTION(bfq_back_seek_max_show, bfqd->bfq_back_max, 0); ++SHOW_FUNCTION(bfq_back_seek_penalty_show, bfqd->bfq_back_penalty, 0); ++SHOW_FUNCTION(bfq_slice_idle_show, bfqd->bfq_slice_idle, 1); ++SHOW_FUNCTION(bfq_max_budget_show, bfqd->bfq_user_max_budget, 0); ++SHOW_FUNCTION(bfq_max_budget_async_rq_show, ++ bfqd->bfq_max_budget_async_rq, 0); ++SHOW_FUNCTION(bfq_timeout_sync_show, bfqd->bfq_timeout[BLK_RW_SYNC], 1); ++SHOW_FUNCTION(bfq_timeout_async_show, bfqd->bfq_timeout[BLK_RW_ASYNC], 1); ++SHOW_FUNCTION(bfq_low_latency_show, bfqd->low_latency, 0); ++SHOW_FUNCTION(bfq_wr_coeff_show, bfqd->bfq_wr_coeff, 0); ++SHOW_FUNCTION(bfq_wr_rt_max_time_show, bfqd->bfq_wr_rt_max_time, 1); ++SHOW_FUNCTION(bfq_wr_min_idle_time_show, bfqd->bfq_wr_min_idle_time, 1); ++SHOW_FUNCTION(bfq_wr_min_inter_arr_async_show, bfqd->bfq_wr_min_inter_arr_async, ++ 1); ++SHOW_FUNCTION(bfq_wr_max_softrt_rate_show, bfqd->bfq_wr_max_softrt_rate, 0); ++#undef SHOW_FUNCTION ++ ++#define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \ ++static ssize_t \ ++__FUNC(struct elevator_queue *e, const char *page, size_t count) \ ++{ \ ++ struct bfq_data *bfqd = e->elevator_data; \ ++ unsigned long uninitialized_var(__data); \ ++ int ret = bfq_var_store(&__data, (page), count); \ ++ if (__data < (MIN)) \ ++ __data = (MIN); \ ++ else if (__data > (MAX)) \ ++ __data = (MAX); \ ++ if (__CONV) \ ++ *(__PTR) = msecs_to_jiffies(__data); \ ++ else \ ++ *(__PTR) = __data; \ ++ return ret; \ ++} ++STORE_FUNCTION(bfq_fifo_expire_sync_store, &bfqd->bfq_fifo_expire[1], 1, ++ INT_MAX, 1); ++STORE_FUNCTION(bfq_fifo_expire_async_store, &bfqd->bfq_fifo_expire[0], 1, ++ INT_MAX, 1); ++STORE_FUNCTION(bfq_back_seek_max_store, &bfqd->bfq_back_max, 0, INT_MAX, 0); ++STORE_FUNCTION(bfq_back_seek_penalty_store, &bfqd->bfq_back_penalty, 1, ++ INT_MAX, 0); ++STORE_FUNCTION(bfq_slice_idle_store, &bfqd->bfq_slice_idle, 0, INT_MAX, 1); ++STORE_FUNCTION(bfq_max_budget_async_rq_store, &bfqd->bfq_max_budget_async_rq, ++ 1, INT_MAX, 0); ++STORE_FUNCTION(bfq_timeout_async_store, &bfqd->bfq_timeout[BLK_RW_ASYNC], 0, ++ INT_MAX, 1); ++STORE_FUNCTION(bfq_wr_coeff_store, &bfqd->bfq_wr_coeff, 1, INT_MAX, 0); ++STORE_FUNCTION(bfq_wr_max_time_store, &bfqd->bfq_wr_max_time, 0, INT_MAX, 1); ++STORE_FUNCTION(bfq_wr_rt_max_time_store, &bfqd->bfq_wr_rt_max_time, 0, INT_MAX, ++ 1); ++STORE_FUNCTION(bfq_wr_min_idle_time_store, &bfqd->bfq_wr_min_idle_time, 0, ++ INT_MAX, 1); ++STORE_FUNCTION(bfq_wr_min_inter_arr_async_store, ++ &bfqd->bfq_wr_min_inter_arr_async, 0, INT_MAX, 1); ++STORE_FUNCTION(bfq_wr_max_softrt_rate_store, &bfqd->bfq_wr_max_softrt_rate, 0, ++ INT_MAX, 0); ++#undef STORE_FUNCTION ++ ++/* do nothing for the moment */ ++static ssize_t bfq_weights_store(struct elevator_queue *e, ++ const char *page, size_t count) ++{ ++ return count; ++} ++ ++static unsigned long bfq_estimated_max_budget(struct bfq_data *bfqd) ++{ ++ u64 timeout = jiffies_to_msecs(bfqd->bfq_timeout[BLK_RW_SYNC]); ++ ++ if (bfqd->peak_rate_samples >= BFQ_PEAK_RATE_SAMPLES) ++ return bfq_calc_max_budget(bfqd->peak_rate, timeout); ++ else ++ return bfq_default_max_budget; ++} ++ ++static ssize_t bfq_max_budget_store(struct elevator_queue *e, ++ const char *page, size_t count) ++{ ++ struct bfq_data *bfqd = e->elevator_data; ++ unsigned long uninitialized_var(__data); ++ int ret = bfq_var_store(&__data, (page), count); ++ ++ if (__data == 0) ++ bfqd->bfq_max_budget = bfq_estimated_max_budget(bfqd); ++ else { ++ if (__data > INT_MAX) ++ __data = INT_MAX; ++ bfqd->bfq_max_budget = __data; ++ } ++ ++ bfqd->bfq_user_max_budget = __data; ++ ++ return ret; ++} ++ ++static ssize_t bfq_timeout_sync_store(struct elevator_queue *e, ++ const char *page, size_t count) ++{ ++ struct bfq_data *bfqd = e->elevator_data; ++ unsigned long uninitialized_var(__data); ++ int ret = bfq_var_store(&__data, (page), count); ++ ++ if (__data < 1) ++ __data = 1; ++ else if (__data > INT_MAX) ++ __data = INT_MAX; ++ ++ bfqd->bfq_timeout[BLK_RW_SYNC] = msecs_to_jiffies(__data); ++ if (bfqd->bfq_user_max_budget == 0) ++ bfqd->bfq_max_budget = bfq_estimated_max_budget(bfqd); ++ ++ return ret; ++} ++ ++static ssize_t bfq_low_latency_store(struct elevator_queue *e, ++ const char *page, size_t count) ++{ ++ struct bfq_data *bfqd = e->elevator_data; ++ unsigned long uninitialized_var(__data); ++ int ret = bfq_var_store(&__data, (page), count); ++ ++ if (__data > 1) ++ __data = 1; ++ if (__data == 0 && bfqd->low_latency != 0) ++ bfq_end_wr(bfqd); ++ bfqd->low_latency = __data; ++ ++ return ret; ++} ++ ++#define BFQ_ATTR(name) \ ++ __ATTR(name, S_IRUGO|S_IWUSR, bfq_##name##_show, bfq_##name##_store) ++ ++static struct elv_fs_entry bfq_attrs[] = { ++ BFQ_ATTR(fifo_expire_sync), ++ BFQ_ATTR(fifo_expire_async), ++ BFQ_ATTR(back_seek_max), ++ BFQ_ATTR(back_seek_penalty), ++ BFQ_ATTR(slice_idle), ++ BFQ_ATTR(max_budget), ++ BFQ_ATTR(max_budget_async_rq), ++ BFQ_ATTR(timeout_sync), ++ BFQ_ATTR(timeout_async), ++ BFQ_ATTR(low_latency), ++ BFQ_ATTR(wr_coeff), ++ BFQ_ATTR(wr_max_time), ++ BFQ_ATTR(wr_rt_max_time), ++ BFQ_ATTR(wr_min_idle_time), ++ BFQ_ATTR(wr_min_inter_arr_async), ++ BFQ_ATTR(wr_max_softrt_rate), ++ BFQ_ATTR(weights), ++ __ATTR_NULL ++}; ++ ++static struct elevator_type iosched_bfq = { ++ .ops = { ++ .elevator_merge_fn = bfq_merge, ++ .elevator_merged_fn = bfq_merged_request, ++ .elevator_merge_req_fn = bfq_merged_requests, ++#ifdef CONFIG_BFQ_GROUP_IOSCHED ++ .elevator_bio_merged_fn = bfq_bio_merged, ++#endif ++ .elevator_allow_merge_fn = bfq_allow_merge, ++ .elevator_dispatch_fn = bfq_dispatch_requests, ++ .elevator_add_req_fn = bfq_insert_request, ++ .elevator_activate_req_fn = bfq_activate_request, ++ .elevator_deactivate_req_fn = bfq_deactivate_request, ++ .elevator_completed_req_fn = bfq_completed_request, ++ .elevator_former_req_fn = elv_rb_former_request, ++ .elevator_latter_req_fn = elv_rb_latter_request, ++ .elevator_init_icq_fn = bfq_init_icq, ++ .elevator_exit_icq_fn = bfq_exit_icq, ++ .elevator_set_req_fn = bfq_set_request, ++ .elevator_put_req_fn = bfq_put_request, ++ .elevator_may_queue_fn = bfq_may_queue, ++ .elevator_init_fn = bfq_init_queue, ++ .elevator_exit_fn = bfq_exit_queue, ++ }, ++ .icq_size = sizeof(struct bfq_io_cq), ++ .icq_align = __alignof__(struct bfq_io_cq), ++ .elevator_attrs = bfq_attrs, ++ .elevator_name = "bfq", ++ .elevator_owner = THIS_MODULE, ++}; ++ ++static int __init bfq_init(void) ++{ ++ int ret; ++ ++ /* ++ * Can be 0 on HZ < 1000 setups. ++ */ ++ if (bfq_slice_idle == 0) ++ bfq_slice_idle = 1; ++ ++ if (bfq_timeout_async == 0) ++ bfq_timeout_async = 1; ++ ++#ifdef CONFIG_BFQ_GROUP_IOSCHED ++ ret = blkcg_policy_register(&blkcg_policy_bfq); ++ if (ret) ++ return ret; ++#endif ++ ++ ret = -ENOMEM; ++ if (bfq_slab_setup()) ++ goto err_pol_unreg; ++ ++ /* ++ * Times to load large popular applications for the typical systems ++ * installed on the reference devices (see the comments before the ++ * definitions of the two arrays). ++ */ ++ T_slow[0] = msecs_to_jiffies(2600); ++ T_slow[1] = msecs_to_jiffies(1000); ++ T_fast[0] = msecs_to_jiffies(5500); ++ T_fast[1] = msecs_to_jiffies(2000); ++ ++ /* ++ * Thresholds that determine the switch between speed classes (see ++ * the comments before the definition of the array). ++ */ ++ device_speed_thresh[0] = (R_fast[0] + R_slow[0]) / 2; ++ device_speed_thresh[1] = (R_fast[1] + R_slow[1]) / 2; ++ ++ ret = elv_register(&iosched_bfq); ++ if (ret) ++ goto err_pol_unreg; ++ ++ pr_info("BFQ I/O-scheduler: v7r10"); ++ ++ return 0; ++ ++err_pol_unreg: ++#ifdef CONFIG_BFQ_GROUP_IOSCHED ++ blkcg_policy_unregister(&blkcg_policy_bfq); ++#endif ++ return ret; ++} ++ ++static void __exit bfq_exit(void) ++{ ++ elv_unregister(&iosched_bfq); ++#ifdef CONFIG_BFQ_GROUP_IOSCHED ++ blkcg_policy_unregister(&blkcg_policy_bfq); ++#endif ++ bfq_slab_kill(); ++} ++ ++module_init(bfq_init); ++module_exit(bfq_exit); ++ ++MODULE_AUTHOR("Arianna Avanzini, Fabio Checconi, Paolo Valente"); ++MODULE_LICENSE("GPL"); +diff --git a/block/bfq-sched.c b/block/bfq-sched.c +new file mode 100644 +index 0000000..9328a1f +--- /dev/null ++++ b/block/bfq-sched.c +@@ -0,0 +1,1197 @@ ++/* ++ * BFQ: Hierarchical B-WF2Q+ scheduler. ++ * ++ * Based on ideas and code from CFQ: ++ * Copyright (C) 2003 Jens Axboe ++ * ++ * Copyright (C) 2008 Fabio Checconi ++ * Paolo Valente ++ * ++ * Copyright (C) 2010 Paolo Valente ++ */ ++ ++#ifdef CONFIG_BFQ_GROUP_IOSCHED ++#define for_each_entity(entity) \ ++ for (; entity ; entity = entity->parent) ++ ++#define for_each_entity_safe(entity, parent) \ ++ for (; entity && ({ parent = entity->parent; 1; }); entity = parent) ++ ++ ++static struct bfq_entity *bfq_lookup_next_entity(struct bfq_sched_data *sd, ++ int extract, ++ struct bfq_data *bfqd); ++ ++static struct bfq_group *bfqq_group(struct bfq_queue *bfqq); ++ ++static void bfq_update_budget(struct bfq_entity *next_in_service) ++{ ++ struct bfq_entity *bfqg_entity; ++ struct bfq_group *bfqg; ++ struct bfq_sched_data *group_sd; ++ ++ BUG_ON(!next_in_service); ++ ++ group_sd = next_in_service->sched_data; ++ ++ bfqg = container_of(group_sd, struct bfq_group, sched_data); ++ /* ++ * bfq_group's my_entity field is not NULL only if the group ++ * is not the root group. We must not touch the root entity ++ * as it must never become an in-service entity. ++ */ ++ bfqg_entity = bfqg->my_entity; ++ if (bfqg_entity) ++ bfqg_entity->budget = next_in_service->budget; ++} ++ ++static int bfq_update_next_in_service(struct bfq_sched_data *sd) ++{ ++ struct bfq_entity *next_in_service; ++ ++ if (sd->in_service_entity) ++ /* will update/requeue at the end of service */ ++ return 0; ++ ++ /* ++ * NOTE: this can be improved in many ways, such as returning ++ * 1 (and thus propagating upwards the update) only when the ++ * budget changes, or caching the bfqq that will be scheduled ++ * next from this subtree. By now we worry more about ++ * correctness than about performance... ++ */ ++ next_in_service = bfq_lookup_next_entity(sd, 0, NULL); ++ sd->next_in_service = next_in_service; ++ ++ if (next_in_service) ++ bfq_update_budget(next_in_service); ++ ++ return 1; ++} ++ ++static void bfq_check_next_in_service(struct bfq_sched_data *sd, ++ struct bfq_entity *entity) ++{ ++ BUG_ON(sd->next_in_service != entity); ++} ++#else ++#define for_each_entity(entity) \ ++ for (; entity ; entity = NULL) ++ ++#define for_each_entity_safe(entity, parent) \ ++ for (parent = NULL; entity ; entity = parent) ++ ++static int bfq_update_next_in_service(struct bfq_sched_data *sd) ++{ ++ return 0; ++} ++ ++static void bfq_check_next_in_service(struct bfq_sched_data *sd, ++ struct bfq_entity *entity) ++{ ++} ++ ++static void bfq_update_budget(struct bfq_entity *next_in_service) ++{ ++} ++#endif ++ ++/* ++ * Shift for timestamp calculations. This actually limits the maximum ++ * service allowed in one timestamp delta (small shift values increase it), ++ * the maximum total weight that can be used for the queues in the system ++ * (big shift values increase it), and the period of virtual time ++ * wraparounds. ++ */ ++#define WFQ_SERVICE_SHIFT 22 ++ ++/** ++ * bfq_gt - compare two timestamps. ++ * @a: first ts. ++ * @b: second ts. ++ * ++ * Return @a > @b, dealing with wrapping correctly. ++ */ ++static int bfq_gt(u64 a, u64 b) ++{ ++ return (s64)(a - b) > 0; ++} ++ ++static struct bfq_queue *bfq_entity_to_bfqq(struct bfq_entity *entity) ++{ ++ struct bfq_queue *bfqq = NULL; ++ ++ BUG_ON(!entity); ++ ++ if (!entity->my_sched_data) ++ bfqq = container_of(entity, struct bfq_queue, entity); ++ ++ return bfqq; ++} ++ ++ ++/** ++ * bfq_delta - map service into the virtual time domain. ++ * @service: amount of service. ++ * @weight: scale factor (weight of an entity or weight sum). ++ */ ++static u64 bfq_delta(unsigned long service, unsigned long weight) ++{ ++ u64 d = (u64)service << WFQ_SERVICE_SHIFT; ++ ++ do_div(d, weight); ++ return d; ++} ++ ++/** ++ * bfq_calc_finish - assign the finish time to an entity. ++ * @entity: the entity to act upon. ++ * @service: the service to be charged to the entity. ++ */ ++static void bfq_calc_finish(struct bfq_entity *entity, unsigned long service) ++{ ++ struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); ++ ++ BUG_ON(entity->weight == 0); ++ ++ entity->finish = entity->start + ++ bfq_delta(service, entity->weight); ++ ++ if (bfqq) { ++ bfq_log_bfqq(bfqq->bfqd, bfqq, ++ "calc_finish: serv %lu, w %d", ++ service, entity->weight); ++ bfq_log_bfqq(bfqq->bfqd, bfqq, ++ "calc_finish: start %llu, finish %llu, delta %llu", ++ entity->start, entity->finish, ++ bfq_delta(service, entity->weight)); ++ } ++} ++ ++/** ++ * bfq_entity_of - get an entity from a node. ++ * @node: the node field of the entity. ++ * ++ * Convert a node pointer to the relative entity. This is used only ++ * to simplify the logic of some functions and not as the generic ++ * conversion mechanism because, e.g., in the tree walking functions, ++ * the check for a %NULL value would be redundant. ++ */ ++static struct bfq_entity *bfq_entity_of(struct rb_node *node) ++{ ++ struct bfq_entity *entity = NULL; ++ ++ if (node) ++ entity = rb_entry(node, struct bfq_entity, rb_node); ++ ++ return entity; ++} ++ ++/** ++ * bfq_extract - remove an entity from a tree. ++ * @root: the tree root. ++ * @entity: the entity to remove. ++ */ ++static void bfq_extract(struct rb_root *root, struct bfq_entity *entity) ++{ ++ BUG_ON(entity->tree != root); ++ ++ entity->tree = NULL; ++ rb_erase(&entity->rb_node, root); ++} ++ ++/** ++ * bfq_idle_extract - extract an entity from the idle tree. ++ * @st: the service tree of the owning @entity. ++ * @entity: the entity being removed. ++ */ ++static void bfq_idle_extract(struct bfq_service_tree *st, ++ struct bfq_entity *entity) ++{ ++ struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); ++ struct rb_node *next; ++ ++ BUG_ON(entity->tree != &st->idle); ++ ++ if (entity == st->first_idle) { ++ next = rb_next(&entity->rb_node); ++ st->first_idle = bfq_entity_of(next); ++ } ++ ++ if (entity == st->last_idle) { ++ next = rb_prev(&entity->rb_node); ++ st->last_idle = bfq_entity_of(next); ++ } ++ ++ bfq_extract(&st->idle, entity); ++ ++ if (bfqq) ++ list_del(&bfqq->bfqq_list); ++} ++ ++/** ++ * bfq_insert - generic tree insertion. ++ * @root: tree root. ++ * @entity: entity to insert. ++ * ++ * This is used for the idle and the active tree, since they are both ++ * ordered by finish time. ++ */ ++static void bfq_insert(struct rb_root *root, struct bfq_entity *entity) ++{ ++ struct bfq_entity *entry; ++ struct rb_node **node = &root->rb_node; ++ struct rb_node *parent = NULL; ++ ++ BUG_ON(entity->tree); ++ ++ while (*node) { ++ parent = *node; ++ entry = rb_entry(parent, struct bfq_entity, rb_node); ++ ++ if (bfq_gt(entry->finish, entity->finish)) ++ node = &parent->rb_left; ++ else ++ node = &parent->rb_right; ++ } ++ ++ rb_link_node(&entity->rb_node, parent, node); ++ rb_insert_color(&entity->rb_node, root); ++ ++ entity->tree = root; ++} ++ ++/** ++ * bfq_update_min - update the min_start field of a entity. ++ * @entity: the entity to update. ++ * @node: one of its children. ++ * ++ * This function is called when @entity may store an invalid value for ++ * min_start due to updates to the active tree. The function assumes ++ * that the subtree rooted at @node (which may be its left or its right ++ * child) has a valid min_start value. ++ */ ++static void bfq_update_min(struct bfq_entity *entity, struct rb_node *node) ++{ ++ struct bfq_entity *child; ++ ++ if (node) { ++ child = rb_entry(node, struct bfq_entity, rb_node); ++ if (bfq_gt(entity->min_start, child->min_start)) ++ entity->min_start = child->min_start; ++ } ++} ++ ++/** ++ * bfq_update_active_node - recalculate min_start. ++ * @node: the node to update. ++ * ++ * @node may have changed position or one of its children may have moved, ++ * this function updates its min_start value. The left and right subtrees ++ * are assumed to hold a correct min_start value. ++ */ ++static void bfq_update_active_node(struct rb_node *node) ++{ ++ struct bfq_entity *entity = rb_entry(node, struct bfq_entity, rb_node); ++ ++ entity->min_start = entity->start; ++ bfq_update_min(entity, node->rb_right); ++ bfq_update_min(entity, node->rb_left); ++} ++ ++/** ++ * bfq_update_active_tree - update min_start for the whole active tree. ++ * @node: the starting node. ++ * ++ * @node must be the deepest modified node after an update. This function ++ * updates its min_start using the values held by its children, assuming ++ * that they did not change, and then updates all the nodes that may have ++ * changed in the path to the root. The only nodes that may have changed ++ * are the ones in the path or their siblings. ++ */ ++static void bfq_update_active_tree(struct rb_node *node) ++{ ++ struct rb_node *parent; ++ ++up: ++ bfq_update_active_node(node); ++ ++ parent = rb_parent(node); ++ if (!parent) ++ return; ++ ++ if (node == parent->rb_left && parent->rb_right) ++ bfq_update_active_node(parent->rb_right); ++ else if (parent->rb_left) ++ bfq_update_active_node(parent->rb_left); ++ ++ node = parent; ++ goto up; ++} ++ ++static void bfq_weights_tree_add(struct bfq_data *bfqd, ++ struct bfq_entity *entity, ++ struct rb_root *root); ++ ++static void bfq_weights_tree_remove(struct bfq_data *bfqd, ++ struct bfq_entity *entity, ++ struct rb_root *root); ++ ++ ++/** ++ * bfq_active_insert - insert an entity in the active tree of its ++ * group/device. ++ * @st: the service tree of the entity. ++ * @entity: the entity being inserted. ++ * ++ * The active tree is ordered by finish time, but an extra key is kept ++ * per each node, containing the minimum value for the start times of ++ * its children (and the node itself), so it's possible to search for ++ * the eligible node with the lowest finish time in logarithmic time. ++ */ ++static void bfq_active_insert(struct bfq_service_tree *st, ++ struct bfq_entity *entity) ++{ ++ struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); ++ struct rb_node *node = &entity->rb_node; ++#ifdef CONFIG_BFQ_GROUP_IOSCHED ++ struct bfq_sched_data *sd = NULL; ++ struct bfq_group *bfqg = NULL; ++ struct bfq_data *bfqd = NULL; ++#endif ++ ++ bfq_insert(&st->active, entity); ++ ++ if (node->rb_left) ++ node = node->rb_left; ++ else if (node->rb_right) ++ node = node->rb_right; ++ ++ bfq_update_active_tree(node); ++ ++#ifdef CONFIG_BFQ_GROUP_IOSCHED ++ sd = entity->sched_data; ++ bfqg = container_of(sd, struct bfq_group, sched_data); ++ BUG_ON(!bfqg); ++ bfqd = (struct bfq_data *)bfqg->bfqd; ++#endif ++ if (bfqq) ++ list_add(&bfqq->bfqq_list, &bfqq->bfqd->active_list); ++#ifdef CONFIG_BFQ_GROUP_IOSCHED ++ else { /* bfq_group */ ++ BUG_ON(!bfqd); ++ bfq_weights_tree_add(bfqd, entity, &bfqd->group_weights_tree); ++ } ++ if (bfqg != bfqd->root_group) { ++ BUG_ON(!bfqg); ++ BUG_ON(!bfqd); ++ bfqg->active_entities++; ++ if (bfqg->active_entities == 2) ++ bfqd->active_numerous_groups++; ++ } ++#endif ++} ++ ++/** ++ * bfq_ioprio_to_weight - calc a weight from an ioprio. ++ * @ioprio: the ioprio value to convert. ++ */ ++static unsigned short bfq_ioprio_to_weight(int ioprio) ++{ ++ BUG_ON(ioprio < 0 || ioprio >= IOPRIO_BE_NR); ++ return IOPRIO_BE_NR * BFQ_WEIGHT_CONVERSION_COEFF - ioprio; ++} ++ ++/** ++ * bfq_weight_to_ioprio - calc an ioprio from a weight. ++ * @weight: the weight value to convert. ++ * ++ * To preserve as much as possible the old only-ioprio user interface, ++ * 0 is used as an escape ioprio value for weights (numerically) equal or ++ * larger than IOPRIO_BE_NR * BFQ_WEIGHT_CONVERSION_COEFF. ++ */ ++static unsigned short bfq_weight_to_ioprio(int weight) ++{ ++ BUG_ON(weight < BFQ_MIN_WEIGHT || weight > BFQ_MAX_WEIGHT); ++ return IOPRIO_BE_NR * BFQ_WEIGHT_CONVERSION_COEFF - weight < 0 ? ++ 0 : IOPRIO_BE_NR * BFQ_WEIGHT_CONVERSION_COEFF - weight; ++} ++ ++static void bfq_get_entity(struct bfq_entity *entity) ++{ ++ struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); ++ ++ if (bfqq) { ++ atomic_inc(&bfqq->ref); ++ bfq_log_bfqq(bfqq->bfqd, bfqq, "get_entity: %p %d", ++ bfqq, atomic_read(&bfqq->ref)); ++ } ++} ++ ++/** ++ * bfq_find_deepest - find the deepest node that an extraction can modify. ++ * @node: the node being removed. ++ * ++ * Do the first step of an extraction in an rb tree, looking for the ++ * node that will replace @node, and returning the deepest node that ++ * the following modifications to the tree can touch. If @node is the ++ * last node in the tree return %NULL. ++ */ ++static struct rb_node *bfq_find_deepest(struct rb_node *node) ++{ ++ struct rb_node *deepest; ++ ++ if (!node->rb_right && !node->rb_left) ++ deepest = rb_parent(node); ++ else if (!node->rb_right) ++ deepest = node->rb_left; ++ else if (!node->rb_left) ++ deepest = node->rb_right; ++ else { ++ deepest = rb_next(node); ++ if (deepest->rb_right) ++ deepest = deepest->rb_right; ++ else if (rb_parent(deepest) != node) ++ deepest = rb_parent(deepest); ++ } ++ ++ return deepest; ++} ++ ++/** ++ * bfq_active_extract - remove an entity from the active tree. ++ * @st: the service_tree containing the tree. ++ * @entity: the entity being removed. ++ */ ++static void bfq_active_extract(struct bfq_service_tree *st, ++ struct bfq_entity *entity) ++{ ++ struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); ++ struct rb_node *node; ++#ifdef CONFIG_BFQ_GROUP_IOSCHED ++ struct bfq_sched_data *sd = NULL; ++ struct bfq_group *bfqg = NULL; ++ struct bfq_data *bfqd = NULL; ++#endif ++ ++ node = bfq_find_deepest(&entity->rb_node); ++ bfq_extract(&st->active, entity); ++ ++ if (node) ++ bfq_update_active_tree(node); ++ ++#ifdef CONFIG_BFQ_GROUP_IOSCHED ++ sd = entity->sched_data; ++ bfqg = container_of(sd, struct bfq_group, sched_data); ++ BUG_ON(!bfqg); ++ bfqd = (struct bfq_data *)bfqg->bfqd; ++#endif ++ if (bfqq) ++ list_del(&bfqq->bfqq_list); ++#ifdef CONFIG_BFQ_GROUP_IOSCHED ++ else { /* bfq_group */ ++ BUG_ON(!bfqd); ++ bfq_weights_tree_remove(bfqd, entity, ++ &bfqd->group_weights_tree); ++ } ++ if (bfqg != bfqd->root_group) { ++ BUG_ON(!bfqg); ++ BUG_ON(!bfqd); ++ BUG_ON(!bfqg->active_entities); ++ bfqg->active_entities--; ++ if (bfqg->active_entities == 1) { ++ BUG_ON(!bfqd->active_numerous_groups); ++ bfqd->active_numerous_groups--; ++ } ++ } ++#endif ++} ++ ++/** ++ * bfq_idle_insert - insert an entity into the idle tree. ++ * @st: the service tree containing the tree. ++ * @entity: the entity to insert. ++ */ ++static void bfq_idle_insert(struct bfq_service_tree *st, ++ struct bfq_entity *entity) ++{ ++ struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); ++ struct bfq_entity *first_idle = st->first_idle; ++ struct bfq_entity *last_idle = st->last_idle; ++ ++ if (!first_idle || bfq_gt(first_idle->finish, entity->finish)) ++ st->first_idle = entity; ++ if (!last_idle || bfq_gt(entity->finish, last_idle->finish)) ++ st->last_idle = entity; ++ ++ bfq_insert(&st->idle, entity); ++ ++ if (bfqq) ++ list_add(&bfqq->bfqq_list, &bfqq->bfqd->idle_list); ++} ++ ++/** ++ * bfq_forget_entity - remove an entity from the wfq trees. ++ * @st: the service tree. ++ * @entity: the entity being removed. ++ * ++ * Update the device status and forget everything about @entity, putting ++ * the device reference to it, if it is a queue. Entities belonging to ++ * groups are not refcounted. ++ */ ++static void bfq_forget_entity(struct bfq_service_tree *st, ++ struct bfq_entity *entity) ++{ ++ struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); ++ struct bfq_sched_data *sd; ++ ++ BUG_ON(!entity->on_st); ++ ++ entity->on_st = 0; ++ st->wsum -= entity->weight; ++ if (bfqq) { ++ sd = entity->sched_data; ++ bfq_log_bfqq(bfqq->bfqd, bfqq, "forget_entity: %p %d", ++ bfqq, atomic_read(&bfqq->ref)); ++ bfq_put_queue(bfqq); ++ } ++} ++ ++/** ++ * bfq_put_idle_entity - release the idle tree ref of an entity. ++ * @st: service tree for the entity. ++ * @entity: the entity being released. ++ */ ++static void bfq_put_idle_entity(struct bfq_service_tree *st, ++ struct bfq_entity *entity) ++{ ++ bfq_idle_extract(st, entity); ++ bfq_forget_entity(st, entity); ++} ++ ++/** ++ * bfq_forget_idle - update the idle tree if necessary. ++ * @st: the service tree to act upon. ++ * ++ * To preserve the global O(log N) complexity we only remove one entry here; ++ * as the idle tree will not grow indefinitely this can be done safely. ++ */ ++static void bfq_forget_idle(struct bfq_service_tree *st) ++{ ++ struct bfq_entity *first_idle = st->first_idle; ++ struct bfq_entity *last_idle = st->last_idle; ++ ++ if (RB_EMPTY_ROOT(&st->active) && last_idle && ++ !bfq_gt(last_idle->finish, st->vtime)) { ++ /* ++ * Forget the whole idle tree, increasing the vtime past ++ * the last finish time of idle entities. ++ */ ++ st->vtime = last_idle->finish; ++ } ++ ++ if (first_idle && !bfq_gt(first_idle->finish, st->vtime)) ++ bfq_put_idle_entity(st, first_idle); ++} ++ ++static struct bfq_service_tree * ++__bfq_entity_update_weight_prio(struct bfq_service_tree *old_st, ++ struct bfq_entity *entity) ++{ ++ struct bfq_service_tree *new_st = old_st; ++ ++ if (entity->prio_changed) { ++ struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); ++ unsigned short prev_weight, new_weight; ++ struct bfq_data *bfqd = NULL; ++ struct rb_root *root; ++#ifdef CONFIG_BFQ_GROUP_IOSCHED ++ struct bfq_sched_data *sd; ++ struct bfq_group *bfqg; ++#endif ++ ++ if (bfqq) ++ bfqd = bfqq->bfqd; ++#ifdef CONFIG_BFQ_GROUP_IOSCHED ++ else { ++ sd = entity->my_sched_data; ++ bfqg = container_of(sd, struct bfq_group, sched_data); ++ BUG_ON(!bfqg); ++ bfqd = (struct bfq_data *)bfqg->bfqd; ++ BUG_ON(!bfqd); ++ } ++#endif ++ ++ BUG_ON(old_st->wsum < entity->weight); ++ old_st->wsum -= entity->weight; ++ ++ if (entity->new_weight != entity->orig_weight) { ++ if (entity->new_weight < BFQ_MIN_WEIGHT || ++ entity->new_weight > BFQ_MAX_WEIGHT) { ++ printk(KERN_CRIT "update_weight_prio: " ++ "new_weight %d\n", ++ entity->new_weight); ++ BUG(); ++ } ++ entity->orig_weight = entity->new_weight; ++ if (bfqq) ++ bfqq->ioprio = ++ bfq_weight_to_ioprio(entity->orig_weight); ++ } ++ ++ if (bfqq) ++ bfqq->ioprio_class = bfqq->new_ioprio_class; ++ entity->prio_changed = 0; ++ ++ /* ++ * NOTE: here we may be changing the weight too early, ++ * this will cause unfairness. The correct approach ++ * would have required additional complexity to defer ++ * weight changes to the proper time instants (i.e., ++ * when entity->finish <= old_st->vtime). ++ */ ++ new_st = bfq_entity_service_tree(entity); ++ ++ prev_weight = entity->weight; ++ new_weight = entity->orig_weight * ++ (bfqq ? bfqq->wr_coeff : 1); ++ /* ++ * If the weight of the entity changes, remove the entity ++ * from its old weight counter (if there is a counter ++ * associated with the entity), and add it to the counter ++ * associated with its new weight. ++ */ ++ if (prev_weight != new_weight) { ++ root = bfqq ? &bfqd->queue_weights_tree : ++ &bfqd->group_weights_tree; ++ bfq_weights_tree_remove(bfqd, entity, root); ++ } ++ entity->weight = new_weight; ++ /* ++ * Add the entity to its weights tree only if it is ++ * not associated with a weight-raised queue. ++ */ ++ if (prev_weight != new_weight && ++ (bfqq ? bfqq->wr_coeff == 1 : 1)) ++ /* If we get here, root has been initialized. */ ++ bfq_weights_tree_add(bfqd, entity, root); ++ ++ new_st->wsum += entity->weight; ++ ++ if (new_st != old_st) ++ entity->start = new_st->vtime; ++ } ++ ++ return new_st; ++} ++ ++#ifdef CONFIG_BFQ_GROUP_IOSCHED ++static void bfqg_stats_set_start_empty_time(struct bfq_group *bfqg); ++#endif ++ ++/** ++ * bfq_bfqq_served - update the scheduler status after selection for ++ * service. ++ * @bfqq: the queue being served. ++ * @served: bytes to transfer. ++ * ++ * NOTE: this can be optimized, as the timestamps of upper level entities ++ * are synchronized every time a new bfqq is selected for service. By now, ++ * we keep it to better check consistency. ++ */ ++static void bfq_bfqq_served(struct bfq_queue *bfqq, int served) ++{ ++ struct bfq_entity *entity = &bfqq->entity; ++ struct bfq_service_tree *st; ++ ++ for_each_entity(entity) { ++ st = bfq_entity_service_tree(entity); ++ ++ entity->service += served; ++ BUG_ON(entity->service > entity->budget); ++ BUG_ON(st->wsum == 0); ++ ++ st->vtime += bfq_delta(served, st->wsum); ++ bfq_forget_idle(st); ++ } ++#ifdef CONFIG_BFQ_GROUP_IOSCHED ++ bfqg_stats_set_start_empty_time(bfqq_group(bfqq)); ++#endif ++ bfq_log_bfqq(bfqq->bfqd, bfqq, "bfqq_served %d secs", served); ++} ++ ++/** ++ * bfq_bfqq_charge_full_budget - set the service to the entity budget. ++ * @bfqq: the queue that needs a service update. ++ * ++ * When it's not possible to be fair in the service domain, because ++ * a queue is not consuming its budget fast enough (the meaning of ++ * fast depends on the timeout parameter), we charge it a full ++ * budget. In this way we should obtain a sort of time-domain ++ * fairness among all the seeky/slow queues. ++ */ ++static void bfq_bfqq_charge_full_budget(struct bfq_queue *bfqq) ++{ ++ struct bfq_entity *entity = &bfqq->entity; ++ ++ bfq_log_bfqq(bfqq->bfqd, bfqq, "charge_full_budget"); ++ ++ bfq_bfqq_served(bfqq, entity->budget - entity->service); ++} ++ ++/** ++ * __bfq_activate_entity - activate an entity. ++ * @entity: the entity being activated. ++ * ++ * Called whenever an entity is activated, i.e., it is not active and one ++ * of its children receives a new request, or has to be reactivated due to ++ * budget exhaustion. It uses the current budget of the entity (and the ++ * service received if @entity is active) of the queue to calculate its ++ * timestamps. ++ */ ++static void __bfq_activate_entity(struct bfq_entity *entity) ++{ ++ struct bfq_sched_data *sd = entity->sched_data; ++ struct bfq_service_tree *st = bfq_entity_service_tree(entity); ++ ++ if (entity == sd->in_service_entity) { ++ BUG_ON(entity->tree); ++ /* ++ * If we are requeueing the current entity we have ++ * to take care of not charging to it service it has ++ * not received. ++ */ ++ bfq_calc_finish(entity, entity->service); ++ entity->start = entity->finish; ++ sd->in_service_entity = NULL; ++ } else if (entity->tree == &st->active) { ++ /* ++ * Requeueing an entity due to a change of some ++ * next_in_service entity below it. We reuse the ++ * old start time. ++ */ ++ bfq_active_extract(st, entity); ++ } else if (entity->tree == &st->idle) { ++ /* ++ * Must be on the idle tree, bfq_idle_extract() will ++ * check for that. ++ */ ++ bfq_idle_extract(st, entity); ++ entity->start = bfq_gt(st->vtime, entity->finish) ? ++ st->vtime : entity->finish; ++ } else { ++ /* ++ * The finish time of the entity may be invalid, and ++ * it is in the past for sure, otherwise the queue ++ * would have been on the idle tree. ++ */ ++ entity->start = st->vtime; ++ st->wsum += entity->weight; ++ bfq_get_entity(entity); ++ ++ BUG_ON(entity->on_st); ++ entity->on_st = 1; ++ } ++ ++ st = __bfq_entity_update_weight_prio(st, entity); ++ bfq_calc_finish(entity, entity->budget); ++ bfq_active_insert(st, entity); ++} ++ ++/** ++ * bfq_activate_entity - activate an entity and its ancestors if necessary. ++ * @entity: the entity to activate. ++ * ++ * Activate @entity and all the entities on the path from it to the root. ++ */ ++static void bfq_activate_entity(struct bfq_entity *entity) ++{ ++ struct bfq_sched_data *sd; ++ ++ for_each_entity(entity) { ++ __bfq_activate_entity(entity); ++ ++ sd = entity->sched_data; ++ if (!bfq_update_next_in_service(sd)) ++ /* ++ * No need to propagate the activation to the ++ * upper entities, as they will be updated when ++ * the in-service entity is rescheduled. ++ */ ++ break; ++ } ++} ++ ++/** ++ * __bfq_deactivate_entity - deactivate an entity from its service tree. ++ * @entity: the entity to deactivate. ++ * @requeue: if false, the entity will not be put into the idle tree. ++ * ++ * Deactivate an entity, independently from its previous state. If the ++ * entity was not on a service tree just return, otherwise if it is on ++ * any scheduler tree, extract it from that tree, and if necessary ++ * and if the caller did not specify @requeue, put it on the idle tree. ++ * ++ * Return %1 if the caller should update the entity hierarchy, i.e., ++ * if the entity was in service or if it was the next_in_service for ++ * its sched_data; return %0 otherwise. ++ */ ++static int __bfq_deactivate_entity(struct bfq_entity *entity, int requeue) ++{ ++ struct bfq_sched_data *sd = entity->sched_data; ++ struct bfq_service_tree *st = bfq_entity_service_tree(entity); ++ int was_in_service = entity == sd->in_service_entity; ++ int ret = 0; ++ ++ if (!entity->on_st) ++ return 0; ++ ++ BUG_ON(was_in_service && entity->tree); ++ ++ if (was_in_service) { ++ bfq_calc_finish(entity, entity->service); ++ sd->in_service_entity = NULL; ++ } else if (entity->tree == &st->active) ++ bfq_active_extract(st, entity); ++ else if (entity->tree == &st->idle) ++ bfq_idle_extract(st, entity); ++ else if (entity->tree) ++ BUG(); ++ ++ if (was_in_service || sd->next_in_service == entity) ++ ret = bfq_update_next_in_service(sd); ++ ++ if (!requeue || !bfq_gt(entity->finish, st->vtime)) ++ bfq_forget_entity(st, entity); ++ else ++ bfq_idle_insert(st, entity); ++ ++ BUG_ON(sd->in_service_entity == entity); ++ BUG_ON(sd->next_in_service == entity); ++ ++ return ret; ++} ++ ++/** ++ * bfq_deactivate_entity - deactivate an entity. ++ * @entity: the entity to deactivate. ++ * @requeue: true if the entity can be put on the idle tree ++ */ ++static void bfq_deactivate_entity(struct bfq_entity *entity, int requeue) ++{ ++ struct bfq_sched_data *sd; ++ struct bfq_entity *parent; ++ ++ for_each_entity_safe(entity, parent) { ++ sd = entity->sched_data; ++ ++ if (!__bfq_deactivate_entity(entity, requeue)) ++ /* ++ * The parent entity is still backlogged, and ++ * we don't need to update it as it is still ++ * in service. ++ */ ++ break; ++ ++ if (sd->next_in_service) ++ /* ++ * The parent entity is still backlogged and ++ * the budgets on the path towards the root ++ * need to be updated. ++ */ ++ goto update; ++ ++ /* ++ * If we reach there the parent is no more backlogged and ++ * we want to propagate the dequeue upwards. ++ */ ++ requeue = 1; ++ } ++ ++ return; ++ ++update: ++ entity = parent; ++ for_each_entity(entity) { ++ __bfq_activate_entity(entity); ++ ++ sd = entity->sched_data; ++ if (!bfq_update_next_in_service(sd)) ++ break; ++ } ++} ++ ++/** ++ * bfq_update_vtime - update vtime if necessary. ++ * @st: the service tree to act upon. ++ * ++ * If necessary update the service tree vtime to have at least one ++ * eligible entity, skipping to its start time. Assumes that the ++ * active tree of the device is not empty. ++ * ++ * NOTE: this hierarchical implementation updates vtimes quite often, ++ * we may end up with reactivated processes getting timestamps after a ++ * vtime skip done because we needed a ->first_active entity on some ++ * intermediate node. ++ */ ++static void bfq_update_vtime(struct bfq_service_tree *st) ++{ ++ struct bfq_entity *entry; ++ struct rb_node *node = st->active.rb_node; ++ ++ entry = rb_entry(node, struct bfq_entity, rb_node); ++ if (bfq_gt(entry->min_start, st->vtime)) { ++ st->vtime = entry->min_start; ++ bfq_forget_idle(st); ++ } ++} ++ ++/** ++ * bfq_first_active_entity - find the eligible entity with ++ * the smallest finish time ++ * @st: the service tree to select from. ++ * ++ * This function searches the first schedulable entity, starting from the ++ * root of the tree and going on the left every time on this side there is ++ * a subtree with at least one eligible (start >= vtime) entity. The path on ++ * the right is followed only if a) the left subtree contains no eligible ++ * entities and b) no eligible entity has been found yet. ++ */ ++static struct bfq_entity *bfq_first_active_entity(struct bfq_service_tree *st) ++{ ++ struct bfq_entity *entry, *first = NULL; ++ struct rb_node *node = st->active.rb_node; ++ ++ while (node) { ++ entry = rb_entry(node, struct bfq_entity, rb_node); ++left: ++ if (!bfq_gt(entry->start, st->vtime)) ++ first = entry; ++ ++ BUG_ON(bfq_gt(entry->min_start, st->vtime)); ++ ++ if (node->rb_left) { ++ entry = rb_entry(node->rb_left, ++ struct bfq_entity, rb_node); ++ if (!bfq_gt(entry->min_start, st->vtime)) { ++ node = node->rb_left; ++ goto left; ++ } ++ } ++ if (first) ++ break; ++ node = node->rb_right; ++ } ++ ++ BUG_ON(!first && !RB_EMPTY_ROOT(&st->active)); ++ return first; ++} ++ ++/** ++ * __bfq_lookup_next_entity - return the first eligible entity in @st. ++ * @st: the service tree. ++ * ++ * Update the virtual time in @st and return the first eligible entity ++ * it contains. ++ */ ++static struct bfq_entity *__bfq_lookup_next_entity(struct bfq_service_tree *st, ++ bool force) ++{ ++ struct bfq_entity *entity, *new_next_in_service = NULL; ++ ++ if (RB_EMPTY_ROOT(&st->active)) ++ return NULL; ++ ++ bfq_update_vtime(st); ++ entity = bfq_first_active_entity(st); ++ BUG_ON(bfq_gt(entity->start, st->vtime)); ++ ++ /* ++ * If the chosen entity does not match with the sched_data's ++ * next_in_service and we are forcedly serving the IDLE priority ++ * class tree, bubble up budget update. ++ */ ++ if (unlikely(force && entity != entity->sched_data->next_in_service)) { ++ new_next_in_service = entity; ++ for_each_entity(new_next_in_service) ++ bfq_update_budget(new_next_in_service); ++ } ++ ++ return entity; ++} ++ ++/** ++ * bfq_lookup_next_entity - return the first eligible entity in @sd. ++ * @sd: the sched_data. ++ * @extract: if true the returned entity will be also extracted from @sd. ++ * ++ * NOTE: since we cache the next_in_service entity at each level of the ++ * hierarchy, the complexity of the lookup can be decreased with ++ * absolutely no effort just returning the cached next_in_service value; ++ * we prefer to do full lookups to test the consistency of * the data ++ * structures. ++ */ ++static struct bfq_entity *bfq_lookup_next_entity(struct bfq_sched_data *sd, ++ int extract, ++ struct bfq_data *bfqd) ++{ ++ struct bfq_service_tree *st = sd->service_tree; ++ struct bfq_entity *entity; ++ int i = 0; ++ ++ BUG_ON(sd->in_service_entity); ++ ++ if (bfqd && ++ jiffies - bfqd->bfq_class_idle_last_service > BFQ_CL_IDLE_TIMEOUT) { ++ entity = __bfq_lookup_next_entity(st + BFQ_IOPRIO_CLASSES - 1, ++ true); ++ if (entity) { ++ i = BFQ_IOPRIO_CLASSES - 1; ++ bfqd->bfq_class_idle_last_service = jiffies; ++ sd->next_in_service = entity; ++ } ++ } ++ for (; i < BFQ_IOPRIO_CLASSES; i++) { ++ entity = __bfq_lookup_next_entity(st + i, false); ++ if (entity) { ++ if (extract) { ++ bfq_check_next_in_service(sd, entity); ++ bfq_active_extract(st + i, entity); ++ sd->in_service_entity = entity; ++ sd->next_in_service = NULL; ++ } ++ break; ++ } ++ } ++ ++ return entity; ++} ++ ++/* ++ * Get next queue for service. ++ */ ++static struct bfq_queue *bfq_get_next_queue(struct bfq_data *bfqd) ++{ ++ struct bfq_entity *entity = NULL; ++ struct bfq_sched_data *sd; ++ struct bfq_queue *bfqq; ++ ++ BUG_ON(bfqd->in_service_queue); ++ ++ if (bfqd->busy_queues == 0) ++ return NULL; ++ ++ sd = &bfqd->root_group->sched_data; ++ for (; sd ; sd = entity->my_sched_data) { ++ entity = bfq_lookup_next_entity(sd, 1, bfqd); ++ BUG_ON(!entity); ++ entity->service = 0; ++ } ++ ++ bfqq = bfq_entity_to_bfqq(entity); ++ BUG_ON(!bfqq); ++ ++ return bfqq; ++} ++ ++static void __bfq_bfqd_reset_in_service(struct bfq_data *bfqd) ++{ ++ if (bfqd->in_service_bic) { ++ put_io_context(bfqd->in_service_bic->icq.ioc); ++ bfqd->in_service_bic = NULL; ++ } ++ ++ bfqd->in_service_queue = NULL; ++ del_timer(&bfqd->idle_slice_timer); ++} ++ ++static void bfq_deactivate_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq, ++ int requeue) ++{ ++ struct bfq_entity *entity = &bfqq->entity; ++ ++ if (bfqq == bfqd->in_service_queue) ++ __bfq_bfqd_reset_in_service(bfqd); ++ ++ bfq_deactivate_entity(entity, requeue); ++} ++ ++static void bfq_activate_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq) ++{ ++ struct bfq_entity *entity = &bfqq->entity; ++ ++ bfq_activate_entity(entity); ++} ++ ++#ifdef CONFIG_BFQ_GROUP_IOSCHED ++static void bfqg_stats_update_dequeue(struct bfq_group *bfqg); ++#endif ++ ++/* ++ * Called when the bfqq no longer has requests pending, remove it from ++ * the service tree. ++ */ ++static void bfq_del_bfqq_busy(struct bfq_data *bfqd, struct bfq_queue *bfqq, ++ int requeue) ++{ ++ BUG_ON(!bfq_bfqq_busy(bfqq)); ++ BUG_ON(!RB_EMPTY_ROOT(&bfqq->sort_list)); ++ ++ bfq_log_bfqq(bfqd, bfqq, "del from busy"); ++ ++ bfq_clear_bfqq_busy(bfqq); ++ ++ BUG_ON(bfqd->busy_queues == 0); ++ bfqd->busy_queues--; ++ ++ if (!bfqq->dispatched) { ++ bfq_weights_tree_remove(bfqd, &bfqq->entity, ++ &bfqd->queue_weights_tree); ++ if (!blk_queue_nonrot(bfqd->queue)) { ++ BUG_ON(!bfqd->busy_in_flight_queues); ++ bfqd->busy_in_flight_queues--; ++ if (bfq_bfqq_constantly_seeky(bfqq)) { ++ BUG_ON(!bfqd-> ++ const_seeky_busy_in_flight_queues); ++ bfqd->const_seeky_busy_in_flight_queues--; ++ } ++ } ++ } ++ if (bfqq->wr_coeff > 1) ++ bfqd->wr_busy_queues--; ++ ++#ifdef CONFIG_BFQ_GROUP_IOSCHED ++ bfqg_stats_update_dequeue(bfqq_group(bfqq)); ++#endif ++ ++ bfq_deactivate_bfqq(bfqd, bfqq, requeue); ++} ++ ++/* ++ * Called when an inactive queue receives a new request. ++ */ ++static void bfq_add_bfqq_busy(struct bfq_data *bfqd, struct bfq_queue *bfqq) ++{ ++ BUG_ON(bfq_bfqq_busy(bfqq)); ++ BUG_ON(bfqq == bfqd->in_service_queue); ++ ++ bfq_log_bfqq(bfqd, bfqq, "add to busy"); ++ ++ bfq_activate_bfqq(bfqd, bfqq); ++ ++ bfq_mark_bfqq_busy(bfqq); ++ bfqd->busy_queues++; ++ ++ if (!bfqq->dispatched) { ++ if (bfqq->wr_coeff == 1) ++ bfq_weights_tree_add(bfqd, &bfqq->entity, ++ &bfqd->queue_weights_tree); ++ if (!blk_queue_nonrot(bfqd->queue)) { ++ bfqd->busy_in_flight_queues++; ++ if (bfq_bfqq_constantly_seeky(bfqq)) ++ bfqd->const_seeky_busy_in_flight_queues++; ++ } ++ } ++ if (bfqq->wr_coeff > 1) ++ bfqd->wr_busy_queues++; ++} +diff --git a/block/bfq.h b/block/bfq.h +new file mode 100644 +index 0000000..9b04d19 +--- /dev/null ++++ b/block/bfq.h +@@ -0,0 +1,807 @@ ++/* ++ * BFQ-v7r10 for 4.4.0: data structures and common functions prototypes. ++ * ++ * Based on ideas and code from CFQ: ++ * Copyright (C) 2003 Jens Axboe ++ * ++ * Copyright (C) 2008 Fabio Checconi ++ * Paolo Valente ++ * ++ * Copyright (C) 2010 Paolo Valente ++ */ ++ ++#ifndef _BFQ_H ++#define _BFQ_H ++ ++#include ++#include ++#include ++#include ++#include ++ ++#define BFQ_IOPRIO_CLASSES 3 ++#define BFQ_CL_IDLE_TIMEOUT (HZ/5) ++ ++#define BFQ_MIN_WEIGHT 1 ++#define BFQ_MAX_WEIGHT 1000 ++#define BFQ_WEIGHT_CONVERSION_COEFF 10 ++ ++#define BFQ_DEFAULT_QUEUE_IOPRIO 4 ++ ++#define BFQ_DEFAULT_GRP_WEIGHT 10 ++#define BFQ_DEFAULT_GRP_IOPRIO 0 ++#define BFQ_DEFAULT_GRP_CLASS IOPRIO_CLASS_BE ++ ++struct bfq_entity; ++ ++/** ++ * struct bfq_service_tree - per ioprio_class service tree. ++ * @active: tree for active entities (i.e., those backlogged). ++ * @idle: tree for idle entities (i.e., those not backlogged, with V <= F_i). ++ * @first_idle: idle entity with minimum F_i. ++ * @last_idle: idle entity with maximum F_i. ++ * @vtime: scheduler virtual time. ++ * @wsum: scheduler weight sum; active and idle entities contribute to it. ++ * ++ * Each service tree represents a B-WF2Q+ scheduler on its own. Each ++ * ioprio_class has its own independent scheduler, and so its own ++ * bfq_service_tree. All the fields are protected by the queue lock ++ * of the containing bfqd. ++ */ ++struct bfq_service_tree { ++ struct rb_root active; ++ struct rb_root idle; ++ ++ struct bfq_entity *first_idle; ++ struct bfq_entity *last_idle; ++ ++ u64 vtime; ++ unsigned long wsum; ++}; ++ ++/** ++ * struct bfq_sched_data - multi-class scheduler. ++ * @in_service_entity: entity in service. ++ * @next_in_service: head-of-the-line entity in the scheduler. ++ * @service_tree: array of service trees, one per ioprio_class. ++ * ++ * bfq_sched_data is the basic scheduler queue. It supports three ++ * ioprio_classes, and can be used either as a toplevel queue or as ++ * an intermediate queue on a hierarchical setup. ++ * @next_in_service points to the active entity of the sched_data ++ * service trees that will be scheduled next. ++ * ++ * The supported ioprio_classes are the same as in CFQ, in descending ++ * priority order, IOPRIO_CLASS_RT, IOPRIO_CLASS_BE, IOPRIO_CLASS_IDLE. ++ * Requests from higher priority queues are served before all the ++ * requests from lower priority queues; among requests of the same ++ * queue requests are served according to B-WF2Q+. ++ * All the fields are protected by the queue lock of the containing bfqd. ++ */ ++struct bfq_sched_data { ++ struct bfq_entity *in_service_entity; ++ struct bfq_entity *next_in_service; ++ struct bfq_service_tree service_tree[BFQ_IOPRIO_CLASSES]; ++}; ++ ++/** ++ * struct bfq_weight_counter - counter of the number of all active entities ++ * with a given weight. ++ * @weight: weight of the entities that this counter refers to. ++ * @num_active: number of active entities with this weight. ++ * @weights_node: weights tree member (see bfq_data's @queue_weights_tree ++ * and @group_weights_tree). ++ */ ++struct bfq_weight_counter { ++ short int weight; ++ unsigned int num_active; ++ struct rb_node weights_node; ++}; ++ ++/** ++ * struct bfq_entity - schedulable entity. ++ * @rb_node: service_tree member. ++ * @weight_counter: pointer to the weight counter associated with this entity. ++ * @on_st: flag, true if the entity is on a tree (either the active or ++ * the idle one of its service_tree). ++ * @finish: B-WF2Q+ finish timestamp (aka F_i). ++ * @start: B-WF2Q+ start timestamp (aka S_i). ++ * @tree: tree the entity is enqueued into; %NULL if not on a tree. ++ * @min_start: minimum start time of the (active) subtree rooted at ++ * this entity; used for O(log N) lookups into active trees. ++ * @service: service received during the last round of service. ++ * @budget: budget used to calculate F_i; F_i = S_i + @budget / @weight. ++ * @weight: weight of the queue ++ * @parent: parent entity, for hierarchical scheduling. ++ * @my_sched_data: for non-leaf nodes in the cgroup hierarchy, the ++ * associated scheduler queue, %NULL on leaf nodes. ++ * @sched_data: the scheduler queue this entity belongs to. ++ * @ioprio: the ioprio in use. ++ * @new_weight: when a weight change is requested, the new weight value. ++ * @orig_weight: original weight, used to implement weight boosting ++ * @prio_changed: flag, true when the user requested a weight, ioprio or ++ * ioprio_class change. ++ * ++ * A bfq_entity is used to represent either a bfq_queue (leaf node in the ++ * cgroup hierarchy) or a bfq_group into the upper level scheduler. Each ++ * entity belongs to the sched_data of the parent group in the cgroup ++ * hierarchy. Non-leaf entities have also their own sched_data, stored ++ * in @my_sched_data. ++ * ++ * Each entity stores independently its priority values; this would ++ * allow different weights on different devices, but this ++ * functionality is not exported to userspace by now. Priorities and ++ * weights are updated lazily, first storing the new values into the ++ * new_* fields, then setting the @prio_changed flag. As soon as ++ * there is a transition in the entity state that allows the priority ++ * update to take place the effective and the requested priority ++ * values are synchronized. ++ * ++ * Unless cgroups are used, the weight value is calculated from the ++ * ioprio to export the same interface as CFQ. When dealing with ++ * ``well-behaved'' queues (i.e., queues that do not spend too much ++ * time to consume their budget and have true sequential behavior, and ++ * when there are no external factors breaking anticipation) the ++ * relative weights at each level of the cgroups hierarchy should be ++ * guaranteed. All the fields are protected by the queue lock of the ++ * containing bfqd. ++ */ ++struct bfq_entity { ++ struct rb_node rb_node; ++ struct bfq_weight_counter *weight_counter; ++ ++ int on_st; ++ ++ u64 finish; ++ u64 start; ++ ++ struct rb_root *tree; ++ ++ u64 min_start; ++ ++ int service, budget; ++ unsigned short weight, new_weight; ++ unsigned short orig_weight; ++ ++ struct bfq_entity *parent; ++ ++ struct bfq_sched_data *my_sched_data; ++ struct bfq_sched_data *sched_data; ++ ++ int prio_changed; ++}; ++ ++struct bfq_group; ++ ++/** ++ * struct bfq_queue - leaf schedulable entity. ++ * @ref: reference counter. ++ * @bfqd: parent bfq_data. ++ * @new_ioprio: when an ioprio change is requested, the new ioprio value. ++ * @ioprio_class: the ioprio_class in use. ++ * @new_ioprio_class: when an ioprio_class change is requested, the new ++ * ioprio_class value. ++ * @new_bfqq: shared bfq_queue if queue is cooperating with ++ * one or more other queues. ++ * @sort_list: sorted list of pending requests. ++ * @next_rq: if fifo isn't expired, next request to serve. ++ * @queued: nr of requests queued in @sort_list. ++ * @allocated: currently allocated requests. ++ * @meta_pending: pending metadata requests. ++ * @fifo: fifo list of requests in sort_list. ++ * @entity: entity representing this queue in the scheduler. ++ * @max_budget: maximum budget allowed from the feedback mechanism. ++ * @budget_timeout: budget expiration (in jiffies). ++ * @dispatched: number of requests on the dispatch list or inside driver. ++ * @flags: status flags. ++ * @bfqq_list: node for active/idle bfqq list inside our bfqd. ++ * @burst_list_node: node for the device's burst list. ++ * @seek_samples: number of seeks sampled ++ * @seek_total: sum of the distances of the seeks sampled ++ * @seek_mean: mean seek distance ++ * @last_request_pos: position of the last request enqueued ++ * @requests_within_timer: number of consecutive pairs of request completion ++ * and arrival, such that the queue becomes idle ++ * after the completion, but the next request arrives ++ * within an idle time slice; used only if the queue's ++ * IO_bound has been cleared. ++ * @pid: pid of the process owning the queue, used for logging purposes. ++ * @last_wr_start_finish: start time of the current weight-raising period if ++ * the @bfq-queue is being weight-raised, otherwise ++ * finish time of the last weight-raising period ++ * @wr_cur_max_time: current max raising time for this queue ++ * @soft_rt_next_start: minimum time instant such that, only if a new ++ * request is enqueued after this time instant in an ++ * idle @bfq_queue with no outstanding requests, then ++ * the task associated with the queue it is deemed as ++ * soft real-time (see the comments to the function ++ * bfq_bfqq_softrt_next_start()) ++ * @last_idle_bklogged: time of the last transition of the @bfq_queue from ++ * idle to backlogged ++ * @service_from_backlogged: cumulative service received from the @bfq_queue ++ * since the last transition from idle to ++ * backlogged ++ * @bic: pointer to the bfq_io_cq owning the bfq_queue, set to %NULL if the ++ * queue is shared ++ * ++ * A bfq_queue is a leaf request queue; it can be associated with an ++ * io_context or more, if it is async or shared between cooperating ++ * processes. @cgroup holds a reference to the cgroup, to be sure that it ++ * does not disappear while a bfqq still references it (mostly to avoid ++ * races between request issuing and task migration followed by cgroup ++ * destruction). ++ * All the fields are protected by the queue lock of the containing bfqd. ++ */ ++struct bfq_queue { ++ atomic_t ref; ++ struct bfq_data *bfqd; ++ ++ unsigned short ioprio, new_ioprio; ++ unsigned short ioprio_class, new_ioprio_class; ++ ++ /* fields for cooperating queues handling */ ++ struct bfq_queue *new_bfqq; ++ struct rb_node pos_node; ++ struct rb_root *pos_root; ++ ++ struct rb_root sort_list; ++ struct request *next_rq; ++ int queued[2]; ++ int allocated[2]; ++ int meta_pending; ++ struct list_head fifo; ++ ++ struct bfq_entity entity; ++ ++ int max_budget; ++ unsigned long budget_timeout; ++ ++ int dispatched; ++ ++ unsigned int flags; ++ ++ struct list_head bfqq_list; ++ ++ struct hlist_node burst_list_node; ++ ++ unsigned int seek_samples; ++ u64 seek_total; ++ sector_t seek_mean; ++ sector_t last_request_pos; ++ ++ unsigned int requests_within_timer; ++ ++ pid_t pid; ++ struct bfq_io_cq *bic; ++ ++ /* weight-raising fields */ ++ unsigned long wr_cur_max_time; ++ unsigned long soft_rt_next_start; ++ unsigned long last_wr_start_finish; ++ unsigned int wr_coeff; ++ unsigned long last_idle_bklogged; ++ unsigned long service_from_backlogged; ++}; ++ ++/** ++ * struct bfq_ttime - per process thinktime stats. ++ * @ttime_total: total process thinktime ++ * @ttime_samples: number of thinktime samples ++ * @ttime_mean: average process thinktime ++ */ ++struct bfq_ttime { ++ unsigned long last_end_request; ++ ++ unsigned long ttime_total; ++ unsigned long ttime_samples; ++ unsigned long ttime_mean; ++}; ++ ++/** ++ * struct bfq_io_cq - per (request_queue, io_context) structure. ++ * @icq: associated io_cq structure ++ * @bfqq: array of two process queues, the sync and the async ++ * @ttime: associated @bfq_ttime struct ++ * @ioprio: per (request_queue, blkcg) ioprio. ++ * @blkcg_id: id of the blkcg the related io_cq belongs to. ++ */ ++struct bfq_io_cq { ++ struct io_cq icq; /* must be the first member */ ++ struct bfq_queue *bfqq[2]; ++ struct bfq_ttime ttime; ++ int ioprio; ++ ++#ifdef CONFIG_BFQ_GROUP_IOSCHED ++ uint64_t blkcg_id; /* the current blkcg ID */ ++#endif ++}; ++ ++enum bfq_device_speed { ++ BFQ_BFQD_FAST, ++ BFQ_BFQD_SLOW, ++}; ++ ++/** ++ * struct bfq_data - per device data structure. ++ * @queue: request queue for the managed device. ++ * @root_group: root bfq_group for the device. ++ * @active_numerous_groups: number of bfq_groups containing more than one ++ * active @bfq_entity. ++ * @queue_weights_tree: rbtree of weight counters of @bfq_queues, sorted by ++ * weight. Used to keep track of whether all @bfq_queues ++ * have the same weight. The tree contains one counter ++ * for each distinct weight associated to some active ++ * and not weight-raised @bfq_queue (see the comments to ++ * the functions bfq_weights_tree_[add|remove] for ++ * further details). ++ * @group_weights_tree: rbtree of non-queue @bfq_entity weight counters, sorted ++ * by weight. Used to keep track of whether all ++ * @bfq_groups have the same weight. The tree contains ++ * one counter for each distinct weight associated to ++ * some active @bfq_group (see the comments to the ++ * functions bfq_weights_tree_[add|remove] for further ++ * details). ++ * @busy_queues: number of bfq_queues containing requests (including the ++ * queue in service, even if it is idling). ++ * @busy_in_flight_queues: number of @bfq_queues containing pending or ++ * in-flight requests, plus the @bfq_queue in ++ * service, even if idle but waiting for the ++ * possible arrival of its next sync request. This ++ * field is updated only if the device is rotational, ++ * but used only if the device is also NCQ-capable. ++ * The reason why the field is updated also for non- ++ * NCQ-capable rotational devices is related to the ++ * fact that the value of @hw_tag may be set also ++ * later than when busy_in_flight_queues may need to ++ * be incremented for the first time(s). Taking also ++ * this possibility into account, to avoid unbalanced ++ * increments/decrements, would imply more overhead ++ * than just updating busy_in_flight_queues ++ * regardless of the value of @hw_tag. ++ * @const_seeky_busy_in_flight_queues: number of constantly-seeky @bfq_queues ++ * (that is, seeky queues that expired ++ * for budget timeout at least once) ++ * containing pending or in-flight ++ * requests, including the in-service ++ * @bfq_queue if constantly seeky. This ++ * field is updated only if the device ++ * is rotational, but used only if the ++ * device is also NCQ-capable (see the ++ * comments to @busy_in_flight_queues). ++ * @wr_busy_queues: number of weight-raised busy @bfq_queues. ++ * @queued: number of queued requests. ++ * @rq_in_driver: number of requests dispatched and waiting for completion. ++ * @sync_flight: number of sync requests in the driver. ++ * @max_rq_in_driver: max number of reqs in driver in the last ++ * @hw_tag_samples completed requests. ++ * @hw_tag_samples: nr of samples used to calculate hw_tag. ++ * @hw_tag: flag set to one if the driver is showing a queueing behavior. ++ * @budgets_assigned: number of budgets assigned. ++ * @idle_slice_timer: timer set when idling for the next sequential request ++ * from the queue in service. ++ * @unplug_work: delayed work to restart dispatching on the request queue. ++ * @in_service_queue: bfq_queue in service. ++ * @in_service_bic: bfq_io_cq (bic) associated with the @in_service_queue. ++ * @last_position: on-disk position of the last served request. ++ * @last_budget_start: beginning of the last budget. ++ * @last_idling_start: beginning of the last idle slice. ++ * @peak_rate: peak transfer rate observed for a budget. ++ * @peak_rate_samples: number of samples used to calculate @peak_rate. ++ * @bfq_max_budget: maximum budget allotted to a bfq_queue before ++ * rescheduling. ++ * @group_list: list of all the bfq_groups active on the device. ++ * @active_list: list of all the bfq_queues active on the device. ++ * @idle_list: list of all the bfq_queues idle on the device. ++ * @bfq_fifo_expire: timeout for async/sync requests; when it expires ++ * requests are served in fifo order. ++ * @bfq_back_penalty: weight of backward seeks wrt forward ones. ++ * @bfq_back_max: maximum allowed backward seek. ++ * @bfq_slice_idle: maximum idling time. ++ * @bfq_user_max_budget: user-configured max budget value ++ * (0 for auto-tuning). ++ * @bfq_max_budget_async_rq: maximum budget (in nr of requests) allotted to ++ * async queues. ++ * @bfq_timeout: timeout for bfq_queues to consume their budget; used to ++ * to prevent seeky queues to impose long latencies to well ++ * behaved ones (this also implies that seeky queues cannot ++ * receive guarantees in the service domain; after a timeout ++ * they are charged for the whole allocated budget, to try ++ * to preserve a behavior reasonably fair among them, but ++ * without service-domain guarantees). ++ * @bfq_coop_thresh: number of queue merges after which a @bfq_queue is ++ * no more granted any weight-raising. ++ * @bfq_failed_cooperations: number of consecutive failed cooperation ++ * chances after which weight-raising is restored ++ * to a queue subject to more than bfq_coop_thresh ++ * queue merges. ++ * @bfq_requests_within_timer: number of consecutive requests that must be ++ * issued within the idle time slice to set ++ * again idling to a queue which was marked as ++ * non-I/O-bound (see the definition of the ++ * IO_bound flag for further details). ++ * @last_ins_in_burst: last time at which a queue entered the current ++ * burst of queues being activated shortly after ++ * each other; for more details about this and the ++ * following parameters related to a burst of ++ * activations, see the comments to the function ++ * @bfq_handle_burst. ++ * @bfq_burst_interval: reference time interval used to decide whether a ++ * queue has been activated shortly after ++ * @last_ins_in_burst. ++ * @burst_size: number of queues in the current burst of queue activations. ++ * @bfq_large_burst_thresh: maximum burst size above which the current ++ * queue-activation burst is deemed as 'large'. ++ * @large_burst: true if a large queue-activation burst is in progress. ++ * @burst_list: head of the burst list (as for the above fields, more details ++ * in the comments to the function bfq_handle_burst). ++ * @low_latency: if set to true, low-latency heuristics are enabled. ++ * @bfq_wr_coeff: maximum factor by which the weight of a weight-raised ++ * queue is multiplied. ++ * @bfq_wr_max_time: maximum duration of a weight-raising period (jiffies). ++ * @bfq_wr_rt_max_time: maximum duration for soft real-time processes. ++ * @bfq_wr_min_idle_time: minimum idle period after which weight-raising ++ * may be reactivated for a queue (in jiffies). ++ * @bfq_wr_min_inter_arr_async: minimum period between request arrivals ++ * after which weight-raising may be ++ * reactivated for an already busy queue ++ * (in jiffies). ++ * @bfq_wr_max_softrt_rate: max service-rate for a soft real-time queue, ++ * sectors per seconds. ++ * @RT_prod: cached value of the product R*T used for computing the maximum ++ * duration of the weight raising automatically. ++ * @device_speed: device-speed class for the low-latency heuristic. ++ * @oom_bfqq: fallback dummy bfqq for extreme OOM conditions. ++ * ++ * All the fields are protected by the @queue lock. ++ */ ++struct bfq_data { ++ struct request_queue *queue; ++ ++ struct bfq_group *root_group; ++ ++#ifdef CONFIG_BFQ_GROUP_IOSCHED ++ int active_numerous_groups; ++#endif ++ ++ struct rb_root queue_weights_tree; ++ struct rb_root group_weights_tree; ++ ++ int busy_queues; ++ int busy_in_flight_queues; ++ int const_seeky_busy_in_flight_queues; ++ int wr_busy_queues; ++ int queued; ++ int rq_in_driver; ++ int sync_flight; ++ ++ int max_rq_in_driver; ++ int hw_tag_samples; ++ int hw_tag; ++ ++ int budgets_assigned; ++ ++ struct timer_list idle_slice_timer; ++ struct work_struct unplug_work; ++ ++ struct bfq_queue *in_service_queue; ++ struct bfq_io_cq *in_service_bic; ++ ++ sector_t last_position; ++ ++ ktime_t last_budget_start; ++ ktime_t last_idling_start; ++ int peak_rate_samples; ++ u64 peak_rate; ++ int bfq_max_budget; ++ ++ struct hlist_head group_list; ++ struct list_head active_list; ++ struct list_head idle_list; ++ ++ unsigned int bfq_fifo_expire[2]; ++ unsigned int bfq_back_penalty; ++ unsigned int bfq_back_max; ++ unsigned int bfq_slice_idle; ++ u64 bfq_class_idle_last_service; ++ ++ int bfq_user_max_budget; ++ int bfq_max_budget_async_rq; ++ unsigned int bfq_timeout[2]; ++ ++ unsigned int bfq_coop_thresh; ++ unsigned int bfq_failed_cooperations; ++ unsigned int bfq_requests_within_timer; ++ ++ unsigned long last_ins_in_burst; ++ unsigned long bfq_burst_interval; ++ int burst_size; ++ unsigned long bfq_large_burst_thresh; ++ bool large_burst; ++ struct hlist_head burst_list; ++ ++ bool low_latency; ++ ++ /* parameters of the low_latency heuristics */ ++ unsigned int bfq_wr_coeff; ++ unsigned int bfq_wr_max_time; ++ unsigned int bfq_wr_rt_max_time; ++ unsigned int bfq_wr_min_idle_time; ++ unsigned long bfq_wr_min_inter_arr_async; ++ unsigned int bfq_wr_max_softrt_rate; ++ u64 RT_prod; ++ enum bfq_device_speed device_speed; ++ ++ struct bfq_queue oom_bfqq; ++}; ++ ++enum bfqq_state_flags { ++ BFQ_BFQQ_FLAG_busy = 0, /* has requests or is in service */ ++ BFQ_BFQQ_FLAG_wait_request, /* waiting for a request */ ++ BFQ_BFQQ_FLAG_must_alloc, /* must be allowed rq alloc */ ++ BFQ_BFQQ_FLAG_fifo_expire, /* FIFO checked in this slice */ ++ BFQ_BFQQ_FLAG_idle_window, /* slice idling enabled */ ++ BFQ_BFQQ_FLAG_sync, /* synchronous queue */ ++ BFQ_BFQQ_FLAG_budget_new, /* no completion with this budget */ ++ BFQ_BFQQ_FLAG_IO_bound, /* ++ * bfqq has timed-out at least once ++ * having consumed at most 2/10 of ++ * its budget ++ */ ++ BFQ_BFQQ_FLAG_in_large_burst, /* ++ * bfqq activated in a large burst, ++ * see comments to bfq_handle_burst. ++ */ ++ BFQ_BFQQ_FLAG_constantly_seeky, /* ++ * bfqq has proved to be slow and ++ * seeky until budget timeout ++ */ ++ BFQ_BFQQ_FLAG_softrt_update, /* ++ * may need softrt-next-start ++ * update ++ */ ++}; ++ ++#define BFQ_BFQQ_FNS(name) \ ++static void bfq_mark_bfqq_##name(struct bfq_queue *bfqq) \ ++{ \ ++ (bfqq)->flags |= (1 << BFQ_BFQQ_FLAG_##name); \ ++} \ ++static void bfq_clear_bfqq_##name(struct bfq_queue *bfqq) \ ++{ \ ++ (bfqq)->flags &= ~(1 << BFQ_BFQQ_FLAG_##name); \ ++} \ ++static int bfq_bfqq_##name(const struct bfq_queue *bfqq) \ ++{ \ ++ return ((bfqq)->flags & (1 << BFQ_BFQQ_FLAG_##name)) != 0; \ ++} ++ ++BFQ_BFQQ_FNS(busy); ++BFQ_BFQQ_FNS(wait_request); ++BFQ_BFQQ_FNS(must_alloc); ++BFQ_BFQQ_FNS(fifo_expire); ++BFQ_BFQQ_FNS(idle_window); ++BFQ_BFQQ_FNS(sync); ++BFQ_BFQQ_FNS(budget_new); ++BFQ_BFQQ_FNS(IO_bound); ++BFQ_BFQQ_FNS(in_large_burst); ++BFQ_BFQQ_FNS(constantly_seeky); ++BFQ_BFQQ_FNS(softrt_update); ++#undef BFQ_BFQQ_FNS ++ ++/* Logging facilities. */ ++#define bfq_log_bfqq(bfqd, bfqq, fmt, args...) \ ++ blk_add_trace_msg((bfqd)->queue, "bfq%d " fmt, (bfqq)->pid, ##args) ++ ++#define bfq_log(bfqd, fmt, args...) \ ++ blk_add_trace_msg((bfqd)->queue, "bfq " fmt, ##args) ++ ++/* Expiration reasons. */ ++enum bfqq_expiration { ++ BFQ_BFQQ_TOO_IDLE = 0, /* ++ * queue has been idling for ++ * too long ++ */ ++ BFQ_BFQQ_BUDGET_TIMEOUT, /* budget took too long to be used */ ++ BFQ_BFQQ_BUDGET_EXHAUSTED, /* budget consumed */ ++ BFQ_BFQQ_NO_MORE_REQUESTS, /* the queue has no more requests */ ++}; ++ ++#ifdef CONFIG_BFQ_GROUP_IOSCHED ++ ++struct bfqg_stats { ++ /* total bytes transferred */ ++ struct blkg_rwstat service_bytes; ++ /* total IOs serviced, post merge */ ++ struct blkg_rwstat serviced; ++ /* number of ios merged */ ++ struct blkg_rwstat merged; ++ /* total time spent on device in ns, may not be accurate w/ queueing */ ++ struct blkg_rwstat service_time; ++ /* total time spent waiting in scheduler queue in ns */ ++ struct blkg_rwstat wait_time; ++ /* number of IOs queued up */ ++ struct blkg_rwstat queued; ++ /* total sectors transferred */ ++ struct blkg_stat sectors; ++ /* total disk time and nr sectors dispatched by this group */ ++ struct blkg_stat time; ++ /* time not charged to this cgroup */ ++ struct blkg_stat unaccounted_time; ++ /* sum of number of ios queued across all samples */ ++ struct blkg_stat avg_queue_size_sum; ++ /* count of samples taken for average */ ++ struct blkg_stat avg_queue_size_samples; ++ /* how many times this group has been removed from service tree */ ++ struct blkg_stat dequeue; ++ /* total time spent waiting for it to be assigned a timeslice. */ ++ struct blkg_stat group_wait_time; ++ /* time spent idling for this blkcg_gq */ ++ struct blkg_stat idle_time; ++ /* total time with empty current active q with other requests queued */ ++ struct blkg_stat empty_time; ++ /* fields after this shouldn't be cleared on stat reset */ ++ uint64_t start_group_wait_time; ++ uint64_t start_idle_time; ++ uint64_t start_empty_time; ++ uint16_t flags; ++}; ++ ++/* ++ * struct bfq_group_data - per-blkcg storage for the blkio subsystem. ++ * ++ * @ps: @blkcg_policy_storage that this structure inherits ++ * @weight: weight of the bfq_group ++ */ ++struct bfq_group_data { ++ /* must be the first member */ ++ struct blkcg_policy_data pd; ++ ++ unsigned short weight; ++}; ++ ++/** ++ * struct bfq_group - per (device, cgroup) data structure. ++ * @entity: schedulable entity to insert into the parent group sched_data. ++ * @sched_data: own sched_data, to contain child entities (they may be ++ * both bfq_queues and bfq_groups). ++ * @bfqd_node: node to be inserted into the @bfqd->group_list list ++ * of the groups active on the same device; used for cleanup. ++ * @bfqd: the bfq_data for the device this group acts upon. ++ * @async_bfqq: array of async queues for all the tasks belonging to ++ * the group, one queue per ioprio value per ioprio_class, ++ * except for the idle class that has only one queue. ++ * @async_idle_bfqq: async queue for the idle class (ioprio is ignored). ++ * @my_entity: pointer to @entity, %NULL for the toplevel group; used ++ * to avoid too many special cases during group creation/ ++ * migration. ++ * @active_entities: number of active entities belonging to the group; ++ * unused for the root group. Used to know whether there ++ * are groups with more than one active @bfq_entity ++ * (see the comments to the function ++ * bfq_bfqq_must_not_expire()). ++ * ++ * Each (device, cgroup) pair has its own bfq_group, i.e., for each cgroup ++ * there is a set of bfq_groups, each one collecting the lower-level ++ * entities belonging to the group that are acting on the same device. ++ * ++ * Locking works as follows: ++ * o @bfqd is protected by the queue lock, RCU is used to access it ++ * from the readers. ++ * o All the other fields are protected by the @bfqd queue lock. ++ */ ++struct bfq_group { ++ /* must be the first member */ ++ struct blkg_policy_data pd; ++ ++ struct bfq_entity entity; ++ struct bfq_sched_data sched_data; ++ ++ struct hlist_node bfqd_node; ++ ++ void *bfqd; ++ ++ struct bfq_queue *async_bfqq[2][IOPRIO_BE_NR]; ++ struct bfq_queue *async_idle_bfqq; ++ ++ struct bfq_entity *my_entity; ++ ++ int active_entities; ++ ++ struct bfqg_stats stats; ++ struct bfqg_stats dead_stats; /* stats pushed from dead children */ ++}; ++ ++#else ++struct bfq_group { ++ struct bfq_sched_data sched_data; ++ ++ struct bfq_queue *async_bfqq[2][IOPRIO_BE_NR]; ++ struct bfq_queue *async_idle_bfqq; ++}; ++#endif ++ ++static struct bfq_queue *bfq_entity_to_bfqq(struct bfq_entity *entity); ++ ++static struct bfq_service_tree * ++bfq_entity_service_tree(struct bfq_entity *entity) ++{ ++ struct bfq_sched_data *sched_data = entity->sched_data; ++ struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); ++ unsigned int idx = bfqq ? bfqq->ioprio_class - 1 : ++ BFQ_DEFAULT_GRP_CLASS; ++ ++ BUG_ON(idx >= BFQ_IOPRIO_CLASSES); ++ BUG_ON(sched_data == NULL); ++ ++ return sched_data->service_tree + idx; ++} ++ ++static struct bfq_queue *bic_to_bfqq(struct bfq_io_cq *bic, bool is_sync) ++{ ++ return bic->bfqq[is_sync]; ++} ++ ++static void bic_set_bfqq(struct bfq_io_cq *bic, struct bfq_queue *bfqq, ++ bool is_sync) ++{ ++ bic->bfqq[is_sync] = bfqq; ++} ++ ++static struct bfq_data *bic_to_bfqd(struct bfq_io_cq *bic) ++{ ++ return bic->icq.q->elevator->elevator_data; ++} ++ ++/** ++ * bfq_get_bfqd_locked - get a lock to a bfqd using a RCU protected pointer. ++ * @ptr: a pointer to a bfqd. ++ * @flags: storage for the flags to be saved. ++ * ++ * This function allows bfqg->bfqd to be protected by the ++ * queue lock of the bfqd they reference; the pointer is dereferenced ++ * under RCU, so the storage for bfqd is assured to be safe as long ++ * as the RCU read side critical section does not end. After the ++ * bfqd->queue->queue_lock is taken the pointer is rechecked, to be ++ * sure that no other writer accessed it. If we raced with a writer, ++ * the function returns NULL, with the queue unlocked, otherwise it ++ * returns the dereferenced pointer, with the queue locked. ++ */ ++static struct bfq_data *bfq_get_bfqd_locked(void **ptr, unsigned long *flags) ++{ ++ struct bfq_data *bfqd; ++ ++ rcu_read_lock(); ++ bfqd = rcu_dereference(*(struct bfq_data **)ptr); ++ ++ if (bfqd != NULL) { ++ spin_lock_irqsave(bfqd->queue->queue_lock, *flags); ++ if (ptr == NULL) ++ printk(KERN_CRIT "get_bfqd_locked pointer NULL\n"); ++ else if (*ptr == bfqd) ++ goto out; ++ spin_unlock_irqrestore(bfqd->queue->queue_lock, *flags); ++ } ++ ++ bfqd = NULL; ++out: ++ rcu_read_unlock(); ++ return bfqd; ++} ++ ++static void bfq_put_bfqd_unlock(struct bfq_data *bfqd, unsigned long *flags) ++{ ++ spin_unlock_irqrestore(bfqd->queue->queue_lock, *flags); ++} ++ ++static void bfq_check_ioprio_change(struct bfq_io_cq *bic, struct bio *bio); ++static void bfq_put_queue(struct bfq_queue *bfqq); ++static void bfq_dispatch_insert(struct request_queue *q, struct request *rq); ++static struct bfq_queue *bfq_get_queue(struct bfq_data *bfqd, ++ struct bio *bio, int is_sync, ++ struct bfq_io_cq *bic, gfp_t gfp_mask); ++static void bfq_end_wr_async_queues(struct bfq_data *bfqd, ++ struct bfq_group *bfqg); ++static void bfq_put_async_queues(struct bfq_data *bfqd, struct bfq_group *bfqg); ++static void bfq_exit_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq); ++ ++#endif /* _BFQ_H */ +-- +1.9.1 + diff --git a/patches/0003-block-bfq-add-Early-Queue-Merge-EQM-to-BFQ-v7r10-for.patch b/patches/0003-block-bfq-add-Early-Queue-Merge-EQM-to-BFQ-v7r10-for.patch new file mode 100644 index 0000000..1b57872 --- /dev/null +++ b/patches/0003-block-bfq-add-Early-Queue-Merge-EQM-to-BFQ-v7r10-for.patch @@ -0,0 +1,1101 @@ +From 8a3e03e4d2c06f9eacf26eb786ccc312dcc2aa8e Mon Sep 17 00:00:00 2001 +From: Mauro Andreolini +Date: Sun, 6 Sep 2015 16:09:05 +0200 +Subject: [PATCH 3/3] block, bfq: add Early Queue Merge (EQM) to BFQ-v7r10 for + 4.4.0 + +A set of processes may happen to perform interleaved reads, i.e.,requests +whose union would give rise to a sequential read pattern. There are two +typical cases: in the first case, processes read fixed-size chunks of +data at a fixed distance from each other, while in the second case processes +may read variable-size chunks at variable distances. The latter case occurs +for example with QEMU, which splits the I/O generated by the guest into +multiple chunks, and lets these chunks be served by a pool of cooperating +processes, iteratively assigning the next chunk of I/O to the first +available process. CFQ uses actual queue merging for the first type of +rocesses, whereas it uses preemption to get a sequential read pattern out +of the read requests performed by the second type of processes. In the end +it uses two different mechanisms to achieve the same goal: boosting the +throughput with interleaved I/O. + +This patch introduces Early Queue Merge (EQM), a unified mechanism to get a +sequential read pattern with both types of processes. The main idea is +checking newly arrived requests against the next request of the active queue +both in case of actual request insert and in case of request merge. By doing +so, both the types of processes can be handled by just merging their queues. +EQM is then simpler and more compact than the pair of mechanisms used in +CFQ. + +Finally, EQM also preserves the typical low-latency properties of BFQ, by +properly restoring the weight-raising state of a queue when it gets back to +a non-merged state. + +Signed-off-by: Mauro Andreolini +Signed-off-by: Arianna Avanzini +Signed-off-by: Paolo Valente +Signed-off-by: Linus Walleij +--- + block/bfq-cgroup.c | 4 + + block/bfq-iosched.c | 687 ++++++++++++++++++++++++++++++++++++++++++++++++++-- + block/bfq.h | 66 +++++ + 3 files changed, 743 insertions(+), 14 deletions(-) + +diff --git a/block/bfq-cgroup.c b/block/bfq-cgroup.c +index 707364a..7a61920 100644 +--- a/block/bfq-cgroup.c ++++ b/block/bfq-cgroup.c +@@ -420,6 +420,7 @@ static void bfq_pd_init(struct blkg_policy_data *pd) + */ + bfqg->bfqd = bfqd; + bfqg->active_entities = 0; ++ bfqg->rq_pos_tree = RB_ROOT; + + /* if the root_group does not exist, we are handling it right now */ + if (bfqd->root_group && bfqg != bfqd->root_group) +@@ -526,6 +527,8 @@ static struct bfq_group *bfq_find_alloc_group(struct bfq_data *bfqd, + return bfqg; + } + ++static void bfq_pos_tree_add_move(struct bfq_data *bfqd, struct bfq_queue *bfqq); ++ + /** + * bfq_bfqq_move - migrate @bfqq to @bfqg. + * @bfqd: queue descriptor. +@@ -573,6 +576,7 @@ static void bfq_bfqq_move(struct bfq_data *bfqd, struct bfq_queue *bfqq, + bfqg_get(bfqg); + + if (busy) { ++ bfq_pos_tree_add_move(bfqd, bfqq); + if (resume) + bfq_activate_bfqq(bfqd, bfqq); + } +diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c +index d61e402..6f8e52a 100644 +--- a/block/bfq-iosched.c ++++ b/block/bfq-iosched.c +@@ -296,6 +296,72 @@ static struct request *bfq_choose_req(struct bfq_data *bfqd, + } + } + ++static struct bfq_queue * ++bfq_rq_pos_tree_lookup(struct bfq_data *bfqd, struct rb_root *root, ++ sector_t sector, struct rb_node **ret_parent, ++ struct rb_node ***rb_link) ++{ ++ struct rb_node **p, *parent; ++ struct bfq_queue *bfqq = NULL; ++ ++ parent = NULL; ++ p = &root->rb_node; ++ while (*p) { ++ struct rb_node **n; ++ ++ parent = *p; ++ bfqq = rb_entry(parent, struct bfq_queue, pos_node); ++ ++ /* ++ * Sort strictly based on sector. Smallest to the left, ++ * largest to the right. ++ */ ++ if (sector > blk_rq_pos(bfqq->next_rq)) ++ n = &(*p)->rb_right; ++ else if (sector < blk_rq_pos(bfqq->next_rq)) ++ n = &(*p)->rb_left; ++ else ++ break; ++ p = n; ++ bfqq = NULL; ++ } ++ ++ *ret_parent = parent; ++ if (rb_link) ++ *rb_link = p; ++ ++ bfq_log(bfqd, "rq_pos_tree_lookup %llu: returning %d", ++ (long long unsigned)sector, ++ bfqq ? bfqq->pid : 0); ++ ++ return bfqq; ++} ++ ++static void bfq_pos_tree_add_move(struct bfq_data *bfqd, struct bfq_queue *bfqq) ++{ ++ struct rb_node **p, *parent; ++ struct bfq_queue *__bfqq; ++ ++ if (bfqq->pos_root) { ++ rb_erase(&bfqq->pos_node, bfqq->pos_root); ++ bfqq->pos_root = NULL; ++ } ++ ++ if (bfq_class_idle(bfqq)) ++ return; ++ if (!bfqq->next_rq) ++ return; ++ ++ bfqq->pos_root = &bfq_bfqq_to_bfqg(bfqq)->rq_pos_tree; ++ __bfqq = bfq_rq_pos_tree_lookup(bfqd, bfqq->pos_root, ++ blk_rq_pos(bfqq->next_rq), &parent, &p); ++ if (!__bfqq) { ++ rb_link_node(&bfqq->pos_node, parent, p); ++ rb_insert_color(&bfqq->pos_node, bfqq->pos_root); ++ } else ++ bfqq->pos_root = NULL; ++} ++ + /* + * Tell whether there are active queues or groups with differentiated weights. + */ +@@ -528,6 +594,57 @@ static unsigned int bfq_wr_duration(struct bfq_data *bfqd) + return dur; + } + ++static unsigned bfq_bfqq_cooperations(struct bfq_queue *bfqq) ++{ ++ return bfqq->bic ? bfqq->bic->cooperations : 0; ++} ++ ++static void ++bfq_bfqq_resume_state(struct bfq_queue *bfqq, struct bfq_io_cq *bic) ++{ ++ if (bic->saved_idle_window) ++ bfq_mark_bfqq_idle_window(bfqq); ++ else ++ bfq_clear_bfqq_idle_window(bfqq); ++ if (bic->saved_IO_bound) ++ bfq_mark_bfqq_IO_bound(bfqq); ++ else ++ bfq_clear_bfqq_IO_bound(bfqq); ++ /* Assuming that the flag in_large_burst is already correctly set */ ++ if (bic->wr_time_left && bfqq->bfqd->low_latency && ++ !bfq_bfqq_in_large_burst(bfqq) && ++ bic->cooperations < bfqq->bfqd->bfq_coop_thresh) { ++ /* ++ * Start a weight raising period with the duration given by ++ * the raising_time_left snapshot. ++ */ ++ if (bfq_bfqq_busy(bfqq)) ++ bfqq->bfqd->wr_busy_queues++; ++ bfqq->wr_coeff = bfqq->bfqd->bfq_wr_coeff; ++ bfqq->wr_cur_max_time = bic->wr_time_left; ++ bfqq->last_wr_start_finish = jiffies; ++ bfqq->entity.prio_changed = 1; ++ } ++ /* ++ * Clear wr_time_left to prevent bfq_bfqq_save_state() from ++ * getting confused about the queue's need of a weight-raising ++ * period. ++ */ ++ bic->wr_time_left = 0; ++} ++ ++static int bfqq_process_refs(struct bfq_queue *bfqq) ++{ ++ int process_refs, io_refs; ++ ++ lockdep_assert_held(bfqq->bfqd->queue->queue_lock); ++ ++ io_refs = bfqq->allocated[READ] + bfqq->allocated[WRITE]; ++ process_refs = atomic_read(&bfqq->ref) - io_refs - bfqq->entity.on_st; ++ BUG_ON(process_refs < 0); ++ return process_refs; ++} ++ + /* Empty burst list and add just bfqq (see comments to bfq_handle_burst) */ + static void bfq_reset_burst_list(struct bfq_data *bfqd, struct bfq_queue *bfqq) + { +@@ -764,8 +881,14 @@ static void bfq_add_request(struct request *rq) + BUG_ON(!next_rq); + bfqq->next_rq = next_rq; + ++ /* ++ * Adjust priority tree position, if next_rq changes. ++ */ ++ if (prev != bfqq->next_rq) ++ bfq_pos_tree_add_move(bfqd, bfqq); ++ + if (!bfq_bfqq_busy(bfqq)) { +- bool soft_rt, in_burst, ++ bool soft_rt, coop_or_in_burst, + idle_for_long_time = time_is_before_jiffies( + bfqq->budget_timeout + + bfqd->bfq_wr_min_idle_time); +@@ -793,11 +916,12 @@ static void bfq_add_request(struct request *rq) + bfqd->last_ins_in_burst = jiffies; + } + +- in_burst = bfq_bfqq_in_large_burst(bfqq); ++ coop_or_in_burst = bfq_bfqq_in_large_burst(bfqq) || ++ bfq_bfqq_cooperations(bfqq) >= bfqd->bfq_coop_thresh; + soft_rt = bfqd->bfq_wr_max_softrt_rate > 0 && +- !in_burst && ++ !coop_or_in_burst && + time_is_before_jiffies(bfqq->soft_rt_next_start); +- interactive = !in_burst && idle_for_long_time; ++ interactive = !coop_or_in_burst && idle_for_long_time; + entity->budget = max_t(unsigned long, bfqq->max_budget, + bfq_serv_to_charge(next_rq, bfqq)); + +@@ -816,6 +940,9 @@ static void bfq_add_request(struct request *rq) + if (!bfqd->low_latency) + goto add_bfqq_busy; + ++ if (bfq_bfqq_just_split(bfqq)) ++ goto set_prio_changed; ++ + /* + * If the queue: + * - is not being boosted, +@@ -840,7 +967,7 @@ static void bfq_add_request(struct request *rq) + } else if (old_wr_coeff > 1) { + if (interactive) + bfqq->wr_cur_max_time = bfq_wr_duration(bfqd); +- else if (in_burst || ++ else if (coop_or_in_burst || + (bfqq->wr_cur_max_time == + bfqd->bfq_wr_rt_max_time && + !soft_rt)) { +@@ -905,6 +1032,7 @@ static void bfq_add_request(struct request *rq) + bfqd->bfq_wr_rt_max_time; + } + } ++set_prio_changed: + if (old_wr_coeff != bfqq->wr_coeff) + entity->prio_changed = 1; + add_bfqq_busy: +@@ -1047,6 +1175,15 @@ static void bfq_merged_request(struct request_queue *q, struct request *req, + bfqd->last_position); + BUG_ON(!next_rq); + bfqq->next_rq = next_rq; ++ /* ++ * If next_rq changes, update both the queue's budget to ++ * fit the new request and the queue's position in its ++ * rq_pos_tree. ++ */ ++ if (prev != bfqq->next_rq) { ++ bfq_updated_next_req(bfqd, bfqq); ++ bfq_pos_tree_add_move(bfqd, bfqq); ++ } + } + } + +@@ -1129,11 +1266,346 @@ static void bfq_end_wr(struct bfq_data *bfqd) + spin_unlock_irq(bfqd->queue->queue_lock); + } + ++static sector_t bfq_io_struct_pos(void *io_struct, bool request) ++{ ++ if (request) ++ return blk_rq_pos(io_struct); ++ else ++ return ((struct bio *)io_struct)->bi_iter.bi_sector; ++} ++ ++static int bfq_rq_close_to_sector(void *io_struct, bool request, ++ sector_t sector) ++{ ++ return abs(bfq_io_struct_pos(io_struct, request) - sector) <= ++ BFQQ_SEEK_THR; ++} ++ ++static struct bfq_queue *bfqq_find_close(struct bfq_data *bfqd, ++ struct bfq_queue *bfqq, ++ sector_t sector) ++{ ++ struct rb_root *root = &bfq_bfqq_to_bfqg(bfqq)->rq_pos_tree; ++ struct rb_node *parent, *node; ++ struct bfq_queue *__bfqq; ++ ++ if (RB_EMPTY_ROOT(root)) ++ return NULL; ++ ++ /* ++ * First, if we find a request starting at the end of the last ++ * request, choose it. ++ */ ++ __bfqq = bfq_rq_pos_tree_lookup(bfqd, root, sector, &parent, NULL); ++ if (__bfqq) ++ return __bfqq; ++ ++ /* ++ * If the exact sector wasn't found, the parent of the NULL leaf ++ * will contain the closest sector (rq_pos_tree sorted by ++ * next_request position). ++ */ ++ __bfqq = rb_entry(parent, struct bfq_queue, pos_node); ++ if (bfq_rq_close_to_sector(__bfqq->next_rq, true, sector)) ++ return __bfqq; ++ ++ if (blk_rq_pos(__bfqq->next_rq) < sector) ++ node = rb_next(&__bfqq->pos_node); ++ else ++ node = rb_prev(&__bfqq->pos_node); ++ if (!node) ++ return NULL; ++ ++ __bfqq = rb_entry(node, struct bfq_queue, pos_node); ++ if (bfq_rq_close_to_sector(__bfqq->next_rq, true, sector)) ++ return __bfqq; ++ ++ return NULL; ++} ++ ++static struct bfq_queue *bfq_find_close_cooperator(struct bfq_data *bfqd, ++ struct bfq_queue *cur_bfqq, ++ sector_t sector) ++{ ++ struct bfq_queue *bfqq; ++ ++ /* ++ * We shall notice if some of the queues are cooperating, ++ * e.g., working closely on the same area of the device. In ++ * that case, we can group them together and: 1) don't waste ++ * time idling, and 2) serve the union of their requests in ++ * the best possible order for throughput. ++ */ ++ bfqq = bfqq_find_close(bfqd, cur_bfqq, sector); ++ if (!bfqq || bfqq == cur_bfqq) ++ return NULL; ++ ++ return bfqq; ++} ++ ++static struct bfq_queue * ++bfq_setup_merge(struct bfq_queue *bfqq, struct bfq_queue *new_bfqq) ++{ ++ int process_refs, new_process_refs; ++ struct bfq_queue *__bfqq; ++ ++ /* ++ * If there are no process references on the new_bfqq, then it is ++ * unsafe to follow the ->new_bfqq chain as other bfqq's in the chain ++ * may have dropped their last reference (not just their last process ++ * reference). ++ */ ++ if (!bfqq_process_refs(new_bfqq)) ++ return NULL; ++ ++ /* Avoid a circular list and skip interim queue merges. */ ++ while ((__bfqq = new_bfqq->new_bfqq)) { ++ if (__bfqq == bfqq) ++ return NULL; ++ new_bfqq = __bfqq; ++ } ++ ++ process_refs = bfqq_process_refs(bfqq); ++ new_process_refs = bfqq_process_refs(new_bfqq); ++ /* ++ * If the process for the bfqq has gone away, there is no ++ * sense in merging the queues. ++ */ ++ if (process_refs == 0 || new_process_refs == 0) ++ return NULL; ++ ++ bfq_log_bfqq(bfqq->bfqd, bfqq, "scheduling merge with queue %d", ++ new_bfqq->pid); ++ ++ /* ++ * Merging is just a redirection: the requests of the process ++ * owning one of the two queues are redirected to the other queue. ++ * The latter queue, in its turn, is set as shared if this is the ++ * first time that the requests of some process are redirected to ++ * it. ++ * ++ * We redirect bfqq to new_bfqq and not the opposite, because we ++ * are in the context of the process owning bfqq, hence we have ++ * the io_cq of this process. So we can immediately configure this ++ * io_cq to redirect the requests of the process to new_bfqq. ++ * ++ * NOTE, even if new_bfqq coincides with the in-service queue, the ++ * io_cq of new_bfqq is not available, because, if the in-service ++ * queue is shared, bfqd->in_service_bic may not point to the ++ * io_cq of the in-service queue. ++ * Redirecting the requests of the process owning bfqq to the ++ * currently in-service queue is in any case the best option, as ++ * we feed the in-service queue with new requests close to the ++ * last request served and, by doing so, hopefully increase the ++ * throughput. ++ */ ++ bfqq->new_bfqq = new_bfqq; ++ atomic_add(process_refs, &new_bfqq->ref); ++ return new_bfqq; ++} ++ ++static bool bfq_may_be_close_cooperator(struct bfq_queue *bfqq, ++ struct bfq_queue *new_bfqq) ++{ ++ if (bfq_class_idle(bfqq) || bfq_class_idle(new_bfqq) || ++ (bfqq->ioprio_class != new_bfqq->ioprio_class)) ++ return false; ++ ++ /* ++ * If either of the queues has already been detected as seeky, ++ * then merging it with the other queue is unlikely to lead to ++ * sequential I/O. ++ */ ++ if (BFQQ_SEEKY(bfqq) || BFQQ_SEEKY(new_bfqq)) ++ return false; ++ ++ /* ++ * Interleaved I/O is known to be done by (some) applications ++ * only for reads, so it does not make sense to merge async ++ * queues. ++ */ ++ if (!bfq_bfqq_sync(bfqq) || !bfq_bfqq_sync(new_bfqq)) ++ return false; ++ ++ return true; ++} ++ ++/* ++ * Attempt to schedule a merge of bfqq with the currently in-service queue ++ * or with a close queue among the scheduled queues. ++ * Return NULL if no merge was scheduled, a pointer to the shared bfq_queue ++ * structure otherwise. ++ * ++ * The OOM queue is not allowed to participate to cooperation: in fact, since ++ * the requests temporarily redirected to the OOM queue could be redirected ++ * again to dedicated queues at any time, the state needed to correctly ++ * handle merging with the OOM queue would be quite complex and expensive ++ * to maintain. Besides, in such a critical condition as an out of memory, ++ * the benefits of queue merging may be little relevant, or even negligible. ++ */ ++static struct bfq_queue * ++bfq_setup_cooperator(struct bfq_data *bfqd, struct bfq_queue *bfqq, ++ void *io_struct, bool request) ++{ ++ struct bfq_queue *in_service_bfqq, *new_bfqq; ++ ++ if (bfqq->new_bfqq) ++ return bfqq->new_bfqq; ++ if (!io_struct || unlikely(bfqq == &bfqd->oom_bfqq)) ++ return NULL; ++ /* If device has only one backlogged bfq_queue, don't search. */ ++ if (bfqd->busy_queues == 1) ++ return NULL; ++ ++ in_service_bfqq = bfqd->in_service_queue; ++ ++ if (!in_service_bfqq || in_service_bfqq == bfqq || ++ !bfqd->in_service_bic || ++ unlikely(in_service_bfqq == &bfqd->oom_bfqq)) ++ goto check_scheduled; ++ ++ if (bfq_rq_close_to_sector(io_struct, request, bfqd->last_position) && ++ bfqq->entity.parent == in_service_bfqq->entity.parent && ++ bfq_may_be_close_cooperator(bfqq, in_service_bfqq)) { ++ new_bfqq = bfq_setup_merge(bfqq, in_service_bfqq); ++ if (new_bfqq) ++ return new_bfqq; ++ } ++ /* ++ * Check whether there is a cooperator among currently scheduled ++ * queues. The only thing we need is that the bio/request is not ++ * NULL, as we need it to establish whether a cooperator exists. ++ */ ++check_scheduled: ++ new_bfqq = bfq_find_close_cooperator(bfqd, bfqq, ++ bfq_io_struct_pos(io_struct, request)); ++ ++ BUG_ON(new_bfqq && bfqq->entity.parent != new_bfqq->entity.parent); ++ ++ if (new_bfqq && likely(new_bfqq != &bfqd->oom_bfqq) && ++ bfq_may_be_close_cooperator(bfqq, new_bfqq)) ++ return bfq_setup_merge(bfqq, new_bfqq); ++ ++ return NULL; ++} ++ ++static void bfq_bfqq_save_state(struct bfq_queue *bfqq) ++{ ++ /* ++ * If !bfqq->bic, the queue is already shared or its requests ++ * have already been redirected to a shared queue; both idle window ++ * and weight raising state have already been saved. Do nothing. ++ */ ++ if (!bfqq->bic) ++ return; ++ if (bfqq->bic->wr_time_left) ++ /* ++ * This is the queue of a just-started process, and would ++ * deserve weight raising: we set wr_time_left to the full ++ * weight-raising duration to trigger weight-raising when ++ * and if the queue is split and the first request of the ++ * queue is enqueued. ++ */ ++ bfqq->bic->wr_time_left = bfq_wr_duration(bfqq->bfqd); ++ else if (bfqq->wr_coeff > 1) { ++ unsigned long wr_duration = ++ jiffies - bfqq->last_wr_start_finish; ++ /* ++ * It may happen that a queue's weight raising period lasts ++ * longer than its wr_cur_max_time, as weight raising is ++ * handled only when a request is enqueued or dispatched (it ++ * does not use any timer). If the weight raising period is ++ * about to end, don't save it. ++ */ ++ if (bfqq->wr_cur_max_time <= wr_duration) ++ bfqq->bic->wr_time_left = 0; ++ else ++ bfqq->bic->wr_time_left = ++ bfqq->wr_cur_max_time - wr_duration; ++ /* ++ * The bfq_queue is becoming shared or the requests of the ++ * process owning the queue are being redirected to a shared ++ * queue. Stop the weight raising period of the queue, as in ++ * both cases it should not be owned by an interactive or ++ * soft real-time application. ++ */ ++ bfq_bfqq_end_wr(bfqq); ++ } else ++ bfqq->bic->wr_time_left = 0; ++ bfqq->bic->saved_idle_window = bfq_bfqq_idle_window(bfqq); ++ bfqq->bic->saved_IO_bound = bfq_bfqq_IO_bound(bfqq); ++ bfqq->bic->saved_in_large_burst = bfq_bfqq_in_large_burst(bfqq); ++ bfqq->bic->was_in_burst_list = !hlist_unhashed(&bfqq->burst_list_node); ++ bfqq->bic->cooperations++; ++ bfqq->bic->failed_cooperations = 0; ++} ++ ++static void bfq_get_bic_reference(struct bfq_queue *bfqq) ++{ ++ /* ++ * If bfqq->bic has a non-NULL value, the bic to which it belongs ++ * is about to begin using a shared bfq_queue. ++ */ ++ if (bfqq->bic) ++ atomic_long_inc(&bfqq->bic->icq.ioc->refcount); ++} ++ ++static void ++bfq_merge_bfqqs(struct bfq_data *bfqd, struct bfq_io_cq *bic, ++ struct bfq_queue *bfqq, struct bfq_queue *new_bfqq) ++{ ++ bfq_log_bfqq(bfqd, bfqq, "merging with queue %lu", ++ (long unsigned)new_bfqq->pid); ++ /* Save weight raising and idle window of the merged queues */ ++ bfq_bfqq_save_state(bfqq); ++ bfq_bfqq_save_state(new_bfqq); ++ if (bfq_bfqq_IO_bound(bfqq)) ++ bfq_mark_bfqq_IO_bound(new_bfqq); ++ bfq_clear_bfqq_IO_bound(bfqq); ++ /* ++ * Grab a reference to the bic, to prevent it from being destroyed ++ * before being possibly touched by a bfq_split_bfqq(). ++ */ ++ bfq_get_bic_reference(bfqq); ++ bfq_get_bic_reference(new_bfqq); ++ /* ++ * Merge queues (that is, let bic redirect its requests to new_bfqq) ++ */ ++ bic_set_bfqq(bic, new_bfqq, 1); ++ bfq_mark_bfqq_coop(new_bfqq); ++ /* ++ * new_bfqq now belongs to at least two bics (it is a shared queue): ++ * set new_bfqq->bic to NULL. bfqq either: ++ * - does not belong to any bic any more, and hence bfqq->bic must ++ * be set to NULL, or ++ * - is a queue whose owning bics have already been redirected to a ++ * different queue, hence the queue is destined to not belong to ++ * any bic soon and bfqq->bic is already NULL (therefore the next ++ * assignment causes no harm). ++ */ ++ new_bfqq->bic = NULL; ++ bfqq->bic = NULL; ++ bfq_put_queue(bfqq); ++} ++ ++static void bfq_bfqq_increase_failed_cooperations(struct bfq_queue *bfqq) ++{ ++ struct bfq_io_cq *bic = bfqq->bic; ++ struct bfq_data *bfqd = bfqq->bfqd; ++ ++ if (bic && bfq_bfqq_cooperations(bfqq) >= bfqd->bfq_coop_thresh) { ++ bic->failed_cooperations++; ++ if (bic->failed_cooperations >= bfqd->bfq_failed_cooperations) ++ bic->cooperations = 0; ++ } ++} ++ + static int bfq_allow_merge(struct request_queue *q, struct request *rq, + struct bio *bio) + { + struct bfq_data *bfqd = q->elevator->elevator_data; + struct bfq_io_cq *bic; ++ struct bfq_queue *bfqq, *new_bfqq; + + /* + * Disallow merge of a sync bio into an async request. +@@ -1150,7 +1622,26 @@ static int bfq_allow_merge(struct request_queue *q, struct request *rq, + if (!bic) + return 0; + +- return bic_to_bfqq(bic, bfq_bio_sync(bio)) == RQ_BFQQ(rq); ++ bfqq = bic_to_bfqq(bic, bfq_bio_sync(bio)); ++ /* ++ * We take advantage of this function to perform an early merge ++ * of the queues of possible cooperating processes. ++ */ ++ if (bfqq) { ++ new_bfqq = bfq_setup_cooperator(bfqd, bfqq, bio, false); ++ if (new_bfqq) { ++ bfq_merge_bfqqs(bfqd, bic, bfqq, new_bfqq); ++ /* ++ * If we get here, the bio will be queued in the ++ * shared queue, i.e., new_bfqq, so use new_bfqq ++ * to decide whether bio and rq can be merged. ++ */ ++ bfqq = new_bfqq; ++ } else ++ bfq_bfqq_increase_failed_cooperations(bfqq); ++ } ++ ++ return bfqq == RQ_BFQQ(rq); + } + + static void __bfq_set_in_service_queue(struct bfq_data *bfqd, +@@ -1349,6 +1840,15 @@ static void __bfq_bfqq_expire(struct bfq_data *bfqd, struct bfq_queue *bfqq) + + __bfq_bfqd_reset_in_service(bfqd); + ++ /* ++ * If this bfqq is shared between multiple processes, check ++ * to make sure that those processes are still issuing I/Os ++ * within the mean seek distance. If not, it may be time to ++ * break the queues apart again. ++ */ ++ if (bfq_bfqq_coop(bfqq) && BFQQ_SEEKY(bfqq)) ++ bfq_mark_bfqq_split_coop(bfqq); ++ + if (RB_EMPTY_ROOT(&bfqq->sort_list)) { + /* + * Overloading budget_timeout field to store the time +@@ -1357,8 +1857,13 @@ static void __bfq_bfqq_expire(struct bfq_data *bfqd, struct bfq_queue *bfqq) + */ + bfqq->budget_timeout = jiffies; + bfq_del_bfqq_busy(bfqd, bfqq, 1); +- } else ++ } else { + bfq_activate_bfqq(bfqd, bfqq); ++ /* ++ * Resort priority tree of potential close cooperators. ++ */ ++ bfq_pos_tree_add_move(bfqd, bfqq); ++ } + } + + /** +@@ -2242,10 +2747,12 @@ static void bfq_update_wr_data(struct bfq_data *bfqd, struct bfq_queue *bfqq) + /* + * If the queue was activated in a burst, or + * too much time has elapsed from the beginning +- * of this weight-raising period, then end weight +- * raising. ++ * of this weight-raising period, or the queue has ++ * exceeded the acceptable number of cooperations, ++ * then end weight raising. + */ + if (bfq_bfqq_in_large_burst(bfqq) || ++ bfq_bfqq_cooperations(bfqq) >= bfqd->bfq_coop_thresh || + time_is_before_jiffies(bfqq->last_wr_start_finish + + bfqq->wr_cur_max_time)) { + bfqq->last_wr_start_finish = jiffies; +@@ -2474,6 +2981,25 @@ static void bfq_put_queue(struct bfq_queue *bfqq) + #endif + } + ++static void bfq_put_cooperator(struct bfq_queue *bfqq) ++{ ++ struct bfq_queue *__bfqq, *next; ++ ++ /* ++ * If this queue was scheduled to merge with another queue, be ++ * sure to drop the reference taken on that queue (and others in ++ * the merge chain). See bfq_setup_merge and bfq_merge_bfqqs. ++ */ ++ __bfqq = bfqq->new_bfqq; ++ while (__bfqq) { ++ if (__bfqq == bfqq) ++ break; ++ next = __bfqq->new_bfqq; ++ bfq_put_queue(__bfqq); ++ __bfqq = next; ++ } ++} ++ + static void bfq_exit_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq) + { + if (bfqq == bfqd->in_service_queue) { +@@ -2484,6 +3010,8 @@ static void bfq_exit_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq) + bfq_log_bfqq(bfqd, bfqq, "exit_bfqq: %p, %d", bfqq, + atomic_read(&bfqq->ref)); + ++ bfq_put_cooperator(bfqq); ++ + bfq_put_queue(bfqq); + } + +@@ -2492,6 +3020,25 @@ static void bfq_init_icq(struct io_cq *icq) + struct bfq_io_cq *bic = icq_to_bic(icq); + + bic->ttime.last_end_request = jiffies; ++ /* ++ * A newly created bic indicates that the process has just ++ * started doing I/O, and is probably mapping into memory its ++ * executable and libraries: it definitely needs weight raising. ++ * There is however the possibility that the process performs, ++ * for a while, I/O close to some other process. EQM intercepts ++ * this behavior and may merge the queue corresponding to the ++ * process with some other queue, BEFORE the weight of the queue ++ * is raised. Merged queues are not weight-raised (they are assumed ++ * to belong to processes that benefit only from high throughput). ++ * If the merge is basically the consequence of an accident, then ++ * the queue will be split soon and will get back its old weight. ++ * It is then important to write down somewhere that this queue ++ * does need weight raising, even if it did not make it to get its ++ * weight raised before being merged. To this purpose, we overload ++ * the field raising_time_left and assign 1 to it, to mark the queue ++ * as needing weight raising. ++ */ ++ bic->wr_time_left = 1; + } + + static void bfq_exit_icq(struct io_cq *icq) +@@ -2505,6 +3052,13 @@ static void bfq_exit_icq(struct io_cq *icq) + } + + if (bic->bfqq[BLK_RW_SYNC]) { ++ /* ++ * If the bic is using a shared queue, put the reference ++ * taken on the io_context when the bic started using a ++ * shared bfq_queue. ++ */ ++ if (bfq_bfqq_coop(bic->bfqq[BLK_RW_SYNC])) ++ put_io_context(icq->ioc); + bfq_exit_bfqq(bfqd, bic->bfqq[BLK_RW_SYNC]); + bic->bfqq[BLK_RW_SYNC] = NULL; + } +@@ -2809,6 +3363,10 @@ static void bfq_update_idle_window(struct bfq_data *bfqd, + if (!bfq_bfqq_sync(bfqq) || bfq_class_idle(bfqq)) + return; + ++ /* Idle window just restored, statistics are meaningless. */ ++ if (bfq_bfqq_just_split(bfqq)) ++ return; ++ + enable_idle = bfq_bfqq_idle_window(bfqq); + + if (atomic_read(&bic->icq.ioc->active_ref) == 0 || +@@ -2856,6 +3414,7 @@ static void bfq_rq_enqueued(struct bfq_data *bfqd, struct bfq_queue *bfqq, + if (bfqq->entity.service > bfq_max_budget(bfqd) / 8 || + !BFQQ_SEEKY(bfqq)) + bfq_update_idle_window(bfqd, bfqq, bic); ++ bfq_clear_bfqq_just_split(bfqq); + + bfq_log_bfqq(bfqd, bfqq, + "rq_enqueued: idle_window=%d (seeky %d, mean %llu)", +@@ -2920,12 +3479,47 @@ static void bfq_rq_enqueued(struct bfq_data *bfqd, struct bfq_queue *bfqq, + static void bfq_insert_request(struct request_queue *q, struct request *rq) + { + struct bfq_data *bfqd = q->elevator->elevator_data; +- struct bfq_queue *bfqq = RQ_BFQQ(rq); ++ struct bfq_queue *bfqq = RQ_BFQQ(rq), *new_bfqq; + + assert_spin_locked(bfqd->queue->queue_lock); + ++ /* ++ * An unplug may trigger a requeue of a request from the device ++ * driver: make sure we are in process context while trying to ++ * merge two bfq_queues. ++ */ ++ if (!in_interrupt()) { ++ new_bfqq = bfq_setup_cooperator(bfqd, bfqq, rq, true); ++ if (new_bfqq) { ++ if (bic_to_bfqq(RQ_BIC(rq), 1) != bfqq) ++ new_bfqq = bic_to_bfqq(RQ_BIC(rq), 1); ++ /* ++ * Release the request's reference to the old bfqq ++ * and make sure one is taken to the shared queue. ++ */ ++ new_bfqq->allocated[rq_data_dir(rq)]++; ++ bfqq->allocated[rq_data_dir(rq)]--; ++ atomic_inc(&new_bfqq->ref); ++ bfq_put_queue(bfqq); ++ if (bic_to_bfqq(RQ_BIC(rq), 1) == bfqq) ++ bfq_merge_bfqqs(bfqd, RQ_BIC(rq), ++ bfqq, new_bfqq); ++ rq->elv.priv[1] = new_bfqq; ++ bfqq = new_bfqq; ++ } else ++ bfq_bfqq_increase_failed_cooperations(bfqq); ++ } ++ + bfq_add_request(rq); + ++ /* ++ * Here a newly-created bfq_queue has already started a weight-raising ++ * period: clear raising_time_left to prevent bfq_bfqq_save_state() ++ * from assigning it a full weight-raising period. See the detailed ++ * comments about this field in bfq_init_icq(). ++ */ ++ if (bfqq->bic) ++ bfqq->bic->wr_time_left = 0; + rq->fifo_time = jiffies + bfqd->bfq_fifo_expire[rq_is_sync(rq)]; + list_add_tail(&rq->queuelist, &bfqq->fifo); + +@@ -3094,6 +3688,32 @@ static void bfq_put_request(struct request *rq) + } + + /* ++ * Returns NULL if a new bfqq should be allocated, or the old bfqq if this ++ * was the last process referring to said bfqq. ++ */ ++static struct bfq_queue * ++bfq_split_bfqq(struct bfq_io_cq *bic, struct bfq_queue *bfqq) ++{ ++ bfq_log_bfqq(bfqq->bfqd, bfqq, "splitting queue"); ++ ++ put_io_context(bic->icq.ioc); ++ ++ if (bfqq_process_refs(bfqq) == 1) { ++ bfqq->pid = current->pid; ++ bfq_clear_bfqq_coop(bfqq); ++ bfq_clear_bfqq_split_coop(bfqq); ++ return bfqq; ++ } ++ ++ bic_set_bfqq(bic, NULL, 1); ++ ++ bfq_put_cooperator(bfqq); ++ ++ bfq_put_queue(bfqq); ++ return NULL; ++} ++ ++/* + * Allocate bfq data structures associated with this request. + */ + static int bfq_set_request(struct request_queue *q, struct request *rq, +@@ -3105,6 +3725,7 @@ static int bfq_set_request(struct request_queue *q, struct request *rq, + const int is_sync = rq_is_sync(rq); + struct bfq_queue *bfqq; + unsigned long flags; ++ bool split = false; + + might_sleep_if(gfpflags_allow_blocking(gfp_mask)); + +@@ -3117,15 +3738,30 @@ static int bfq_set_request(struct request_queue *q, struct request *rq, + + bfq_bic_update_cgroup(bic, bio); + ++new_queue: + bfqq = bic_to_bfqq(bic, is_sync); + if (!bfqq || bfqq == &bfqd->oom_bfqq) { + bfqq = bfq_get_queue(bfqd, bio, is_sync, bic, gfp_mask); + bic_set_bfqq(bic, bfqq, is_sync); +- if (is_sync) { +- if (bfqd->large_burst) ++ if (split && is_sync) { ++ if ((bic->was_in_burst_list && bfqd->large_burst) || ++ bic->saved_in_large_burst) + bfq_mark_bfqq_in_large_burst(bfqq); +- else +- bfq_clear_bfqq_in_large_burst(bfqq); ++ else { ++ bfq_clear_bfqq_in_large_burst(bfqq); ++ if (bic->was_in_burst_list) ++ hlist_add_head(&bfqq->burst_list_node, ++ &bfqd->burst_list); ++ } ++ } ++ } else { ++ /* If the queue was seeky for too long, break it apart. */ ++ if (bfq_bfqq_coop(bfqq) && bfq_bfqq_split_coop(bfqq)) { ++ bfq_log_bfqq(bfqd, bfqq, "breaking apart bfqq"); ++ bfqq = bfq_split_bfqq(bic, bfqq); ++ split = true; ++ if (!bfqq) ++ goto new_queue; + } + } + +@@ -3137,6 +3773,26 @@ static int bfq_set_request(struct request_queue *q, struct request *rq, + rq->elv.priv[0] = bic; + rq->elv.priv[1] = bfqq; + ++ /* ++ * If a bfq_queue has only one process reference, it is owned ++ * by only one bfq_io_cq: we can set the bic field of the ++ * bfq_queue to the address of that structure. Also, if the ++ * queue has just been split, mark a flag so that the ++ * information is available to the other scheduler hooks. ++ */ ++ if (likely(bfqq != &bfqd->oom_bfqq) && bfqq_process_refs(bfqq) == 1) { ++ bfqq->bic = bic; ++ if (split) { ++ bfq_mark_bfqq_just_split(bfqq); ++ /* ++ * If the queue has just been split from a shared ++ * queue, restore the idle window and the possible ++ * weight raising period. ++ */ ++ bfq_bfqq_resume_state(bfqq, bic); ++ } ++ } ++ + spin_unlock_irqrestore(q->queue_lock, flags); + + return 0; +@@ -3289,6 +3945,7 @@ static void bfq_init_root_group(struct bfq_group *root_group, + root_group->my_entity = NULL; + root_group->bfqd = bfqd; + #endif ++ root_group->rq_pos_tree = RB_ROOT; + for (i = 0; i < BFQ_IOPRIO_CLASSES; i++) + root_group->sched_data.service_tree[i] = BFQ_SERVICE_TREE_INIT; + } +@@ -3369,6 +4026,8 @@ static int bfq_init_queue(struct request_queue *q, struct elevator_type *e) + bfqd->bfq_timeout[BLK_RW_ASYNC] = bfq_timeout_async; + bfqd->bfq_timeout[BLK_RW_SYNC] = bfq_timeout_sync; + ++ bfqd->bfq_coop_thresh = 2; ++ bfqd->bfq_failed_cooperations = 7000; + bfqd->bfq_requests_within_timer = 120; + + bfqd->bfq_large_burst_thresh = 11; +diff --git a/block/bfq.h b/block/bfq.h +index 9b04d19..97a677f 100644 +--- a/block/bfq.h ++++ b/block/bfq.h +@@ -183,6 +183,8 @@ struct bfq_group; + * ioprio_class value. + * @new_bfqq: shared bfq_queue if queue is cooperating with + * one or more other queues. ++ * @pos_node: request-position tree member (see bfq_group's @rq_pos_tree). ++ * @pos_root: request-position tree root (see bfq_group's @rq_pos_tree). + * @sort_list: sorted list of pending requests. + * @next_rq: if fifo isn't expired, next request to serve. + * @queued: nr of requests queued in @sort_list. +@@ -304,6 +306,26 @@ struct bfq_ttime { + * @ttime: associated @bfq_ttime struct + * @ioprio: per (request_queue, blkcg) ioprio. + * @blkcg_id: id of the blkcg the related io_cq belongs to. ++ * @wr_time_left: snapshot of the time left before weight raising ends ++ * for the sync queue associated to this process; this ++ * snapshot is taken to remember this value while the weight ++ * raising is suspended because the queue is merged with a ++ * shared queue, and is used to set @raising_cur_max_time ++ * when the queue is split from the shared queue and its ++ * weight is raised again ++ * @saved_idle_window: same purpose as the previous field for the idle ++ * window ++ * @saved_IO_bound: same purpose as the previous two fields for the I/O ++ * bound classification of a queue ++ * @saved_in_large_burst: same purpose as the previous fields for the ++ * value of the field keeping the queue's belonging ++ * to a large burst ++ * @was_in_burst_list: true if the queue belonged to a burst list ++ * before its merge with another cooperating queue ++ * @cooperations: counter of consecutive successful queue merges underwent ++ * by any of the process' @bfq_queues ++ * @failed_cooperations: counter of consecutive failed queue merges of any ++ * of the process' @bfq_queues + */ + struct bfq_io_cq { + struct io_cq icq; /* must be the first member */ +@@ -314,6 +336,16 @@ struct bfq_io_cq { + #ifdef CONFIG_BFQ_GROUP_IOSCHED + uint64_t blkcg_id; /* the current blkcg ID */ + #endif ++ ++ unsigned int wr_time_left; ++ bool saved_idle_window; ++ bool saved_IO_bound; ++ ++ bool saved_in_large_burst; ++ bool was_in_burst_list; ++ ++ unsigned int cooperations; ++ unsigned int failed_cooperations; + }; + + enum bfq_device_speed { +@@ -559,6 +591,9 @@ enum bfqq_state_flags { + * may need softrt-next-start + * update + */ ++ BFQ_BFQQ_FLAG_coop, /* bfqq is shared */ ++ BFQ_BFQQ_FLAG_split_coop, /* shared bfqq will be split */ ++ BFQ_BFQQ_FLAG_just_split, /* queue has just been split */ + }; + + #define BFQ_BFQQ_FNS(name) \ +@@ -585,6 +620,9 @@ BFQ_BFQQ_FNS(budget_new); + BFQ_BFQQ_FNS(IO_bound); + BFQ_BFQQ_FNS(in_large_burst); + BFQ_BFQQ_FNS(constantly_seeky); ++BFQ_BFQQ_FNS(coop); ++BFQ_BFQQ_FNS(split_coop); ++BFQ_BFQQ_FNS(just_split); + BFQ_BFQQ_FNS(softrt_update); + #undef BFQ_BFQQ_FNS + +@@ -679,6 +717,9 @@ struct bfq_group_data { + * are groups with more than one active @bfq_entity + * (see the comments to the function + * bfq_bfqq_must_not_expire()). ++ * @rq_pos_tree: rbtree sorted by next_request position, used when ++ * determining if two or more queues have interleaving ++ * requests (see bfq_find_close_cooperator()). + * + * Each (device, cgroup) pair has its own bfq_group, i.e., for each cgroup + * there is a set of bfq_groups, each one collecting the lower-level +@@ -707,6 +748,8 @@ struct bfq_group { + + int active_entities; + ++ struct rb_root rq_pos_tree; ++ + struct bfqg_stats stats; + struct bfqg_stats dead_stats; /* stats pushed from dead children */ + }; +@@ -717,6 +760,8 @@ struct bfq_group { + + struct bfq_queue *async_bfqq[2][IOPRIO_BE_NR]; + struct bfq_queue *async_idle_bfqq; ++ ++ struct rb_root rq_pos_tree; + }; + #endif + +@@ -793,6 +838,27 @@ static void bfq_put_bfqd_unlock(struct bfq_data *bfqd, unsigned long *flags) + spin_unlock_irqrestore(bfqd->queue->queue_lock, *flags); + } + ++#ifdef CONFIG_BFQ_GROUP_IOSCHED ++ ++static struct bfq_group *bfq_bfqq_to_bfqg(struct bfq_queue *bfqq) ++{ ++ struct bfq_entity *group_entity = bfqq->entity.parent; ++ ++ if (!group_entity) ++ group_entity = &bfqq->bfqd->root_group->entity; ++ ++ return container_of(group_entity, struct bfq_group, entity); ++} ++ ++#else ++ ++static struct bfq_group *bfq_bfqq_to_bfqg(struct bfq_queue *bfqq) ++{ ++ return bfqq->bfqd->root_group; ++} ++ ++#endif ++ + static void bfq_check_ioprio_change(struct bfq_io_cq *bic, struct bio *bio); + static void bfq_put_queue(struct bfq_queue *bfqq); + static void bfq_dispatch_insert(struct request_queue *q, struct request *rq); +-- +1.9.1 + diff --git a/patches/enable_additional_cpu_optimizations_for_gcc_v4.9+_kernel_v3.15+.patch b/patches/enable_additional_cpu_optimizations_for_gcc_v4.9+_kernel_v3.15+.patch new file mode 100644 index 0000000..d9729b2 --- /dev/null +++ b/patches/enable_additional_cpu_optimizations_for_gcc_v4.9+_kernel_v3.15+.patch @@ -0,0 +1,426 @@ +WARNING - this version of the patch works with version 4.9+ of gcc and with +kernel version 3.15.x+ and should NOT be applied when compiling on older +versions due to name changes of the flags with the 4.9 release of gcc. +Use the older version of this patch hosted on the same github for older +versions of gcc. For example: + +corei7 --> nehalem +corei7-avx --> sandybridge +core-avx-i --> ivybridge +core-avx2 --> haswell + +For more, see: https://gcc.gnu.org/gcc-4.9/changes.html + +It also changes 'atom' to 'bonnell' in accordance with the gcc v4.9 changes. +Note that upstream is using the deprecated 'match=atom' flags when I believe it +should use the newer 'march=bonnell' flag for atom processors. + +I have made that change to this patch set as well. See the following kernel +bug report to see if I'm right: https://bugzilla.kernel.org/show_bug.cgi?id=77461 + +This patch will expand the number of microarchitectures to include newer +processors including: AMD K10-family, AMD Family 10h (Barcelona), AMD Family +14h (Bobcat), AMD Family 15h (Bulldozer), AMD Family 15h (Piledriver), AMD +Family 15h (Steamroller), Family 16h (Jaguar), Intel 1st Gen Core i3/i5/i7 +(Nehalem), Intel 1.5 Gen Core i3/i5/i7 (Westmere), Intel 2nd Gen Core i3/i5/i7 +(Sandybridge), Intel 3rd Gen Core i3/i5/i7 (Ivybridge), Intel 4th Gen Core +i3/i5/i7 (Haswell), Intel 5th Gen Core i3/i5/i7 (Broadwell), and the low power +Silvermont series of Atom processors (Silvermont). It also offers the compiler +the 'native' flag. + +Small but real speed increases are measurable using a make endpoint comparing +a generic kernel to one built with one of the respective microarchs. + +See the following experimental evidence supporting this statement: +https://github.com/graysky2/kernel_gcc_patch + +REQUIREMENTS +linux version >=3.15 +gcc version >=4.9 + +--- a/arch/x86/include/asm/module.h 2015-08-30 14:34:09.000000000 -0400 ++++ b/arch/x86/include/asm/module.h 2015-11-06 14:18:24.234941036 -0500 +@@ -15,6 +15,24 @@ + #define MODULE_PROC_FAMILY "586MMX " + #elif defined CONFIG_MCORE2 + #define MODULE_PROC_FAMILY "CORE2 " ++#elif defined CONFIG_MNATIVE ++#define MODULE_PROC_FAMILY "NATIVE " ++#elif defined CONFIG_MNEHALEM ++#define MODULE_PROC_FAMILY "NEHALEM " ++#elif defined CONFIG_MWESTMERE ++#define MODULE_PROC_FAMILY "WESTMERE " ++#elif defined CONFIG_MSILVERMONT ++#define MODULE_PROC_FAMILY "SILVERMONT " ++#elif defined CONFIG_MSANDYBRIDGE ++#define MODULE_PROC_FAMILY "SANDYBRIDGE " ++#elif defined CONFIG_MIVYBRIDGE ++#define MODULE_PROC_FAMILY "IVYBRIDGE " ++#elif defined CONFIG_MHASWELL ++#define MODULE_PROC_FAMILY "HASWELL " ++#elif defined CONFIG_MBROADWELL ++#define MODULE_PROC_FAMILY "BROADWELL " ++#elif defined CONFIG_MSKYLAKE ++#define MODULE_PROC_FAMILY "SKYLAKE " + #elif defined CONFIG_MATOM + #define MODULE_PROC_FAMILY "ATOM " + #elif defined CONFIG_M686 +@@ -33,6 +51,22 @@ + #define MODULE_PROC_FAMILY "K7 " + #elif defined CONFIG_MK8 + #define MODULE_PROC_FAMILY "K8 " ++#elif defined CONFIG_MK8SSE3 ++#define MODULE_PROC_FAMILY "K8SSE3 " ++#elif defined CONFIG_MK10 ++#define MODULE_PROC_FAMILY "K10 " ++#elif defined CONFIG_MBARCELONA ++#define MODULE_PROC_FAMILY "BARCELONA " ++#elif defined CONFIG_MBOBCAT ++#define MODULE_PROC_FAMILY "BOBCAT " ++#elif defined CONFIG_MBULLDOZER ++#define MODULE_PROC_FAMILY "BULLDOZER " ++#elif defined CONFIG_MPILEDRIVER ++#define MODULE_PROC_FAMILY "STEAMROLLER " ++#elif defined CONFIG_MSTEAMROLLER ++#define MODULE_PROC_FAMILY "PILEDRIVER " ++#elif defined CONFIG_MJAGUAR ++#define MODULE_PROC_FAMILY "JAGUAR " + #elif defined CONFIG_MELAN + #define MODULE_PROC_FAMILY "ELAN " + #elif defined CONFIG_MCRUSOE +--- a/arch/x86/Kconfig.cpu 2015-08-30 14:34:09.000000000 -0400 ++++ b/arch/x86/Kconfig.cpu 2015-11-06 14:20:14.948369244 -0500 +@@ -137,9 +137,8 @@ config MPENTIUM4 + -Paxville + -Dempsey + +- + config MK6 +- bool "K6/K6-II/K6-III" ++ bool "AMD K6/K6-II/K6-III" + depends on X86_32 + ---help--- + Select this for an AMD K6-family processor. Enables use of +@@ -147,7 +146,7 @@ config MK6 + flags to GCC. + + config MK7 +- bool "Athlon/Duron/K7" ++ bool "AMD Athlon/Duron/K7" + depends on X86_32 + ---help--- + Select this for an AMD Athlon K7-family processor. Enables use of +@@ -155,12 +154,69 @@ config MK7 + flags to GCC. + + config MK8 +- bool "Opteron/Athlon64/Hammer/K8" ++ bool "AMD Opteron/Athlon64/Hammer/K8" + ---help--- + Select this for an AMD Opteron or Athlon64 Hammer-family processor. + Enables use of some extended instructions, and passes appropriate + optimization flags to GCC. + ++config MK8SSE3 ++ bool "AMD Opteron/Athlon64/Hammer/K8 with SSE3" ++ ---help--- ++ Select this for improved AMD Opteron or Athlon64 Hammer-family processors. ++ Enables use of some extended instructions, and passes appropriate ++ optimization flags to GCC. ++ ++config MK10 ++ bool "AMD 61xx/7x50/PhenomX3/X4/II/K10" ++ ---help--- ++ Select this for an AMD 61xx Eight-Core Magny-Cours, Athlon X2 7x50, ++ Phenom X3/X4/II, Athlon II X2/X3/X4, or Turion II-family processor. ++ Enables use of some extended instructions, and passes appropriate ++ optimization flags to GCC. ++ ++config MBARCELONA ++ bool "AMD Barcelona" ++ ---help--- ++ Select this for AMD Barcelona and newer processors. ++ ++ Enables -march=barcelona ++ ++config MBOBCAT ++ bool "AMD Bobcat" ++ ---help--- ++ Select this for AMD Bobcat processors. ++ ++ Enables -march=btver1 ++ ++config MBULLDOZER ++ bool "AMD Bulldozer" ++ ---help--- ++ Select this for AMD Bulldozer processors. ++ ++ Enables -march=bdver1 ++ ++config MPILEDRIVER ++ bool "AMD Piledriver" ++ ---help--- ++ Select this for AMD Piledriver processors. ++ ++ Enables -march=bdver2 ++ ++config MSTEAMROLLER ++ bool "AMD Steamroller" ++ ---help--- ++ Select this for AMD Steamroller processors. ++ ++ Enables -march=bdver3 ++ ++config MJAGUAR ++ bool "AMD Jaguar" ++ ---help--- ++ Select this for AMD Jaguar processors. ++ ++ Enables -march=btver2 ++ + config MCRUSOE + bool "Crusoe" + depends on X86_32 +@@ -251,8 +307,17 @@ config MPSC + using the cpu family field + in /proc/cpuinfo. Family 15 is an older Xeon, Family 6 a newer one. + ++config MATOM ++ bool "Intel Atom" ++ ---help--- ++ ++ Select this for the Intel Atom platform. Intel Atom CPUs have an ++ in-order pipelining architecture and thus can benefit from ++ accordingly optimized code. Use a recent GCC with specific Atom ++ support in order to fully benefit from selecting this option. ++ + config MCORE2 +- bool "Core 2/newer Xeon" ++ bool "Intel Core 2" + ---help--- + + Select this for Intel Core 2 and newer Core 2 Xeons (Xeon 51xx and +@@ -260,14 +325,71 @@ config MCORE2 + family in /proc/cpuinfo. Newer ones have 6 and older ones 15 + (not a typo) + +-config MATOM +- bool "Intel Atom" ++ Enables -march=core2 ++ ++config MNEHALEM ++ bool "Intel Nehalem" + ---help--- + +- Select this for the Intel Atom platform. Intel Atom CPUs have an +- in-order pipelining architecture and thus can benefit from +- accordingly optimized code. Use a recent GCC with specific Atom +- support in order to fully benefit from selecting this option. ++ Select this for 1st Gen Core processors in the Nehalem family. ++ ++ Enables -march=nehalem ++ ++config MWESTMERE ++ bool "Intel Westmere" ++ ---help--- ++ ++ Select this for the Intel Westmere formerly Nehalem-C family. ++ ++ Enables -march=westmere ++ ++config MSILVERMONT ++ bool "Intel Silvermont" ++ ---help--- ++ ++ Select this for the Intel Silvermont platform. ++ ++ Enables -march=silvermont ++ ++config MSANDYBRIDGE ++ bool "Intel Sandy Bridge" ++ ---help--- ++ ++ Select this for 2nd Gen Core processors in the Sandy Bridge family. ++ ++ Enables -march=sandybridge ++ ++config MIVYBRIDGE ++ bool "Intel Ivy Bridge" ++ ---help--- ++ ++ Select this for 3rd Gen Core processors in the Ivy Bridge family. ++ ++ Enables -march=ivybridge ++ ++config MHASWELL ++ bool "Intel Haswell" ++ ---help--- ++ ++ Select this for 4th Gen Core processors in the Haswell family. ++ ++ Enables -march=haswell ++ ++config MBROADWELL ++ bool "Intel Broadwell" ++ ---help--- ++ ++ Select this for 5th Gen Core processors in the Broadwell family. ++ ++ Enables -march=broadwell ++ ++config MSKYLAKE ++ bool "Intel Skylake" ++ ---help--- ++ ++ Select this for 6th Gen Core processors in the Skylake family. ++ ++ Enables -march=skylake + + config GENERIC_CPU + bool "Generic-x86-64" +@@ -276,6 +398,19 @@ config GENERIC_CPU + Generic x86-64 CPU. + Run equally well on all x86-64 CPUs. + ++config MNATIVE ++ bool "Native optimizations autodetected by GCC" ++ ---help--- ++ ++ GCC 4.2 and above support -march=native, which automatically detects ++ the optimum settings to use based on your processor. -march=native ++ also detects and applies additional settings beyond -march specific ++ to your CPU, (eg. -msse4). Unless you have a specific reason not to ++ (e.g. distcc cross-compiling), you should probably be using ++ -march=native rather than anything listed below. ++ ++ Enables -march=native ++ + endchoice + + config X86_GENERIC +@@ -300,7 +435,7 @@ config X86_INTERNODE_CACHE_SHIFT + config X86_L1_CACHE_SHIFT + int + default "7" if MPENTIUM4 || MPSC +- default "6" if MK7 || MK8 || MPENTIUMM || MCORE2 || MATOM || MVIAC7 || X86_GENERIC || GENERIC_CPU ++ default "6" if MK7 || MK8 || MK8SSE3 || MK10 || MBARCELONA || MBOBCAT || MBULLDOZER || MPILEDRIVER || MSTEAMROLLER || MJAGUAR || MPENTIUMM || MCORE2 || MNEHALEM || MWESTMERE || MSILVERMONT || MSANDYBRIDGE || MIVYBRIDGE || MHASWELL || MBROADWELL || MSKYLAKE || MNATIVE || MATOM || MVIAC7 || X86_GENERIC || GENERIC_CPU + default "4" if MELAN || M486 || MGEODEGX1 + default "5" if MWINCHIP3D || MWINCHIPC6 || MCRUSOE || MEFFICEON || MCYRIXIII || MK6 || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || M586TSC || M586 || MVIAC3_2 || MGEODE_LX + +@@ -331,11 +466,11 @@ config X86_ALIGNMENT_16 + + config X86_INTEL_USERCOPY + def_bool y +- depends on MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M586MMX || X86_GENERIC || MK8 || MK7 || MEFFICEON || MCORE2 ++ depends on MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M586MMX || X86_GENERIC || MK8 || MK8SSE3 || MK7 || MEFFICEON || MCORE2 || MK10 || MBARCELONA || MNEHALEM || MWESTMERE || MSILVERMONT || MSANDYBRIDGE || MIVYBRIDGE || MHASWELL || MBROADWELL || MSKYLAKE || MNATIVE + + config X86_USE_PPRO_CHECKSUM + def_bool y +- depends on MWINCHIP3D || MWINCHIPC6 || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MK8 || MVIAC3_2 || MVIAC7 || MEFFICEON || MGEODE_LX || MCORE2 || MATOM ++ depends on MWINCHIP3D || MWINCHIPC6 || MCYRIXIII || MK7 || MK6 || MK10 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MK8 || MK8SSE3 || MVIAC3_2 || MVIAC7 || MEFFICEON || MGEODE_LX || MCORE2 || MNEHALEM || MWESTMERE || MSILVERMONT || MSANDYBRIDGE || MIVYBRIDGE || MHASWELL || MBROADWELL || MSKYLAKE || MATOM || MNATIVE + + config X86_USE_3DNOW + def_bool y +@@ -359,17 +494,17 @@ config X86_P6_NOP + + config X86_TSC + def_bool y +- depends on (MWINCHIP3D || MCRUSOE || MEFFICEON || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || M586TSC || MK8 || MVIAC3_2 || MVIAC7 || MGEODEGX1 || MGEODE_LX || MCORE2 || MATOM) || X86_64 ++ depends on (MWINCHIP3D || MCRUSOE || MEFFICEON || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || M586TSC || MK8 || MK8SSE3 || MVIAC3_2 || MVIAC7 || MGEODEGX1 || MGEODE_LX || MCORE2 || MNEHALEM || MWESTMERE || MSILVERMONT || MSANDYBRIDGE || MIVYBRIDGE || MHASWELL || MBROADWELL || MSKYLAKE || MNATIVE || MATOM) || X86_64 + + config X86_CMPXCHG64 + def_bool y +- depends on X86_PAE || X86_64 || MCORE2 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MATOM ++ depends on X86_PAE || X86_64 || MCORE2 || MNEHALEM || MWESTMERE || MSILVERMONT || MSANDYBRIDGE || MIVYBRIDGE || MHASWELL || MBROADWELL || MSKYLAKE || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MATOM || MNATIVE + + # this should be set for all -march=.. options where the compiler + # generates cmov. + config X86_CMOV + def_bool y +- depends on (MK8 || MK7 || MCORE2 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MVIAC3_2 || MVIAC7 || MCRUSOE || MEFFICEON || X86_64 || MATOM || MGEODE_LX) ++ depends on (MK8 || MK8SSE3 || MK10 || MBARCELONA || MBOBCAT || MBULLDOZER || MPILEDRIVER || MSTEAMROLLER || MJAGUAR || MK7 || MCORE2 || MNEHALEM || MWESTMERE || MSILVERMONT || MSANDYBRIDGE || MIVYBRIDGE || MHASWELL || MBROADWELL || MSKYLAKE || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MVIAC3_2 || MVIAC7 || MCRUSOE || MEFFICEON || X86_64 || MNATIVE || MATOM || MGEODE_LX) + + config X86_MINIMUM_CPU_FAMILY + int +--- a/arch/x86/Makefile 2015-08-30 14:34:09.000000000 -0400 ++++ b/arch/x86/Makefile 2015-11-06 14:21:05.708983344 -0500 +@@ -94,13 +94,38 @@ else + KBUILD_CFLAGS += $(call cc-option,-mskip-rax-setup) + + # FIXME - should be integrated in Makefile.cpu (Makefile_32.cpu) ++ cflags-$(CONFIG_MNATIVE) += $(call cc-option,-march=native) + cflags-$(CONFIG_MK8) += $(call cc-option,-march=k8) ++ cflags-$(CONFIG_MK8SSE3) += $(call cc-option,-march=k8-sse3,-mtune=k8) ++ cflags-$(CONFIG_MK10) += $(call cc-option,-march=amdfam10) ++ cflags-$(CONFIG_MBARCELONA) += $(call cc-option,-march=barcelona) ++ cflags-$(CONFIG_MBOBCAT) += $(call cc-option,-march=btver1) ++ cflags-$(CONFIG_MBULLDOZER) += $(call cc-option,-march=bdver1) ++ cflags-$(CONFIG_MPILEDRIVER) += $(call cc-option,-march=bdver2) ++ cflags-$(CONFIG_MSTEAMROLLER) += $(call cc-option,-march=bdver3) ++ cflags-$(CONFIG_MJAGUAR) += $(call cc-option,-march=btver2) + cflags-$(CONFIG_MPSC) += $(call cc-option,-march=nocona) + + cflags-$(CONFIG_MCORE2) += \ +- $(call cc-option,-march=core2,$(call cc-option,-mtune=generic)) +- cflags-$(CONFIG_MATOM) += $(call cc-option,-march=atom) \ +- $(call cc-option,-mtune=atom,$(call cc-option,-mtune=generic)) ++ $(call cc-option,-march=core2,$(call cc-option,-mtune=core2)) ++ cflags-$(CONFIG_MNEHALEM) += \ ++ $(call cc-option,-march=nehalem,$(call cc-option,-mtune=nehalem)) ++ cflags-$(CONFIG_MWESTMERE) += \ ++ $(call cc-option,-march=westmere,$(call cc-option,-mtune=westmere)) ++ cflags-$(CONFIG_MSILVERMONT) += \ ++ $(call cc-option,-march=silvermont,$(call cc-option,-mtune=silvermont)) ++ cflags-$(CONFIG_MSANDYBRIDGE) += \ ++ $(call cc-option,-march=sandybridge,$(call cc-option,-mtune=sandybridge)) ++ cflags-$(CONFIG_MIVYBRIDGE) += \ ++ $(call cc-option,-march=ivybridge,$(call cc-option,-mtune=ivybridge)) ++ cflags-$(CONFIG_MHASWELL) += \ ++ $(call cc-option,-march=haswell,$(call cc-option,-mtune=haswell)) ++ cflags-$(CONFIG_MBROADWELL) += \ ++ $(call cc-option,-march=broadwell,$(call cc-option,-mtune=broadwell)) ++ cflags-$(CONFIG_MSKYLAKE) += \ ++ $(call cc-option,-march=skylake,$(call cc-option,-mtune=skylake)) ++ cflags-$(CONFIG_MATOM) += $(call cc-option,-march=bonnell) \ ++ $(call cc-option,-mtune=bonnell,$(call cc-option,-mtune=generic)) + cflags-$(CONFIG_GENERIC_CPU) += $(call cc-option,-mtune=generic) + KBUILD_CFLAGS += $(cflags-y) + +--- a/arch/x86/Makefile_32.cpu 2015-08-30 14:34:09.000000000 -0400 ++++ b/arch/x86/Makefile_32.cpu 2015-11-06 14:21:43.604429077 -0500 +@@ -23,7 +23,16 @@ cflags-$(CONFIG_MK6) += -march=k6 + # Please note, that patches that add -march=athlon-xp and friends are pointless. + # They make zero difference whatsosever to performance at this time. + cflags-$(CONFIG_MK7) += -march=athlon ++cflags-$(CONFIG_MNATIVE) += $(call cc-option,-march=native) + cflags-$(CONFIG_MK8) += $(call cc-option,-march=k8,-march=athlon) ++cflags-$(CONFIG_MK8SSE3) += $(call cc-option,-march=k8-sse3,-march=athlon) ++cflags-$(CONFIG_MK10) += $(call cc-option,-march=amdfam10,-march=athlon) ++cflags-$(CONFIG_MBARCELONA) += $(call cc-option,-march=barcelona,-march=athlon) ++cflags-$(CONFIG_MBOBCAT) += $(call cc-option,-march=btver1,-march=athlon) ++cflags-$(CONFIG_MBULLDOZER) += $(call cc-option,-march=bdver1,-march=athlon) ++cflags-$(CONFIG_MPILEDRIVER) += $(call cc-option,-march=bdver2,-march=athlon) ++cflags-$(CONFIG_MSTEAMROLLER) += $(call cc-option,-march=bdver3,-march=athlon) ++cflags-$(CONFIG_MJAGUAR) += $(call cc-option,-march=btver2,-march=athlon) + cflags-$(CONFIG_MCRUSOE) += -march=i686 $(align)-functions=0 $(align)-jumps=0 $(align)-loops=0 + cflags-$(CONFIG_MEFFICEON) += -march=i686 $(call tune,pentium3) $(align)-functions=0 $(align)-jumps=0 $(align)-loops=0 + cflags-$(CONFIG_MWINCHIPC6) += $(call cc-option,-march=winchip-c6,-march=i586) +@@ -32,8 +41,16 @@ cflags-$(CONFIG_MCYRIXIII) += $(call cc- + cflags-$(CONFIG_MVIAC3_2) += $(call cc-option,-march=c3-2,-march=i686) + cflags-$(CONFIG_MVIAC7) += -march=i686 + cflags-$(CONFIG_MCORE2) += -march=i686 $(call tune,core2) +-cflags-$(CONFIG_MATOM) += $(call cc-option,-march=atom,$(call cc-option,-march=core2,-march=i686)) \ +- $(call cc-option,-mtune=atom,$(call cc-option,-mtune=generic)) ++cflags-$(CONFIG_MNEHALEM) += -march=i686 $(call tune,nehalem) ++cflags-$(CONFIG_MWESTMERE) += -march=i686 $(call tune,westmere) ++cflags-$(CONFIG_MSILVERMONT) += -march=i686 $(call tune,silvermont) ++cflags-$(CONFIG_MSANDYBRIDGE) += -march=i686 $(call tune,sandybridge) ++cflags-$(CONFIG_MIVYBRIDGE) += -march=i686 $(call tune,ivybridge) ++cflags-$(CONFIG_MHASWELL) += -march=i686 $(call tune,haswell) ++cflags-$(CONFIG_MBROADWELL) += -march=i686 $(call tune,broadwell) ++cflags-$(CONFIG_MSKYLAKE) += -march=i686 $(call tune,skylake) ++cflags-$(CONFIG_MATOM) += $(call cc-option,-march=bonnell,$(call cc-option,-march=core2,-march=i686)) \ ++ $(call cc-option,-mtune=bonnell,$(call cc-option,-mtune=generic)) + + # AMD Elan support + cflags-$(CONFIG_MELAN) += -march=i486 diff --git a/patches_disabled/3.12-sched-bfs-444.patch b/patches_disabled/3.12-sched-bfs-444.patch new file mode 100644 index 0000000..23633cd --- /dev/null +++ b/patches_disabled/3.12-sched-bfs-444.patch @@ -0,0 +1,8876 @@ +The Brain Fuck Scheduler v0.444 by Con Kolivas. + +A single shared runqueue O(n) strict fairness earliest deadline first design. + +Excellent throughput and latency for 1 to many CPUs on desktop and server +commodity hardware. +Not recommended for 4096 cpus. + +Scalability is optimal when your workload is equal to the number of CPUs on +bfs. ie you should ONLY do make -j4 on quad core, -j2 on dual core and so on. + +Features SCHED_IDLEPRIO and SCHED_ISO scheduling policies as well. +You do NOT need to use these policies for good performance, they are purely +optional for even better performance in extreme conditions. + +To run something idleprio, use schedtool like so: + +schedtool -D -e make -j4 + +To run something isoprio, use schedtool like so: + +schedtool -I -e amarok + +Includes accurate sub-tick accounting of tasks so userspace reported +cpu usage may be very different if you have very short lived tasks. + +-ck + +--- + Documentation/scheduler/sched-BFS.txt | 347 + + Documentation/sysctl/kernel.txt | 26 + arch/powerpc/platforms/cell/spufs/sched.c | 5 + drivers/cpufreq/cpufreq.c | 7 + drivers/cpufreq/cpufreq_conservative.c | 4 + drivers/cpufreq/cpufreq_ondemand.c | 4 + fs/proc/base.c | 2 + include/linux/init_task.h | 64 + include/linux/ioprio.h | 2 + include/linux/jiffies.h | 2 + include/linux/sched.h | 88 + include/linux/sched/rt.h | 13 + include/uapi/linux/sched.h | 9 + init/Kconfig | 58 + init/main.c | 3 + kernel/delayacct.c | 2 + kernel/exit.c | 2 + kernel/posix-cpu-timers.c | 14 + kernel/sched/Makefile | 8 + kernel/sched/bfs.c | 7494 ++++++++++++++++++++++++++++++ + kernel/sched/bfs_sched.h | 116 + kernel/sched/stats.c | 4 + kernel/stop_machine.c | 3 + kernel/sysctl.c | 31 + kernel/time/Kconfig | 2 + lib/Kconfig.debug | 2 + 26 files changed, 8240 insertions(+), 72 deletions(-) + +Index: linux-3.12-ck2/arch/powerpc/platforms/cell/spufs/sched.c +=================================================================== +--- linux-3.12-ck2.orig/arch/powerpc/platforms/cell/spufs/sched.c 2013-12-03 20:12:21.186148542 +1100 ++++ linux-3.12-ck2/arch/powerpc/platforms/cell/spufs/sched.c 2013-12-03 20:12:21.153148955 +1100 +@@ -64,11 +64,6 @@ static struct timer_list spusched_timer; + static struct timer_list spuloadavg_timer; + + /* +- * Priority of a normal, non-rt, non-niced'd process (aka nice level 0). +- */ +-#define NORMAL_PRIO 120 +- +-/* + * Frequency of the spu scheduler tick. By default we do one SPU scheduler + * tick for every 10 CPU scheduler ticks. + */ +Index: linux-3.12-ck2/Documentation/scheduler/sched-BFS.txt +=================================================================== +--- /dev/null 1970-01-01 00:00:00.000000000 +0000 ++++ linux-3.12-ck2/Documentation/scheduler/sched-BFS.txt 2013-12-03 20:12:21.154148942 +1100 +@@ -0,0 +1,347 @@ ++BFS - The Brain Fuck Scheduler by Con Kolivas. ++ ++Goals. ++ ++The goal of the Brain Fuck Scheduler, referred to as BFS from here on, is to ++completely do away with the complex designs of the past for the cpu process ++scheduler and instead implement one that is very simple in basic design. ++The main focus of BFS is to achieve excellent desktop interactivity and ++responsiveness without heuristics and tuning knobs that are difficult to ++understand, impossible to model and predict the effect of, and when tuned to ++one workload cause massive detriment to another. ++ ++ ++Design summary. ++ ++BFS is best described as a single runqueue, O(n) lookup, earliest effective ++virtual deadline first design, loosely based on EEVDF (earliest eligible virtual ++deadline first) and my previous Staircase Deadline scheduler. Each component ++shall be described in order to understand the significance of, and reasoning for ++it. The codebase when the first stable version was released was approximately ++9000 lines less code than the existing mainline linux kernel scheduler (in ++2.6.31). This does not even take into account the removal of documentation and ++the cgroups code that is not used. ++ ++Design reasoning. ++ ++The single runqueue refers to the queued but not running processes for the ++entire system, regardless of the number of CPUs. The reason for going back to ++a single runqueue design is that once multiple runqueues are introduced, ++per-CPU or otherwise, there will be complex interactions as each runqueue will ++be responsible for the scheduling latency and fairness of the tasks only on its ++own runqueue, and to achieve fairness and low latency across multiple CPUs, any ++advantage in throughput of having CPU local tasks causes other disadvantages. ++This is due to requiring a very complex balancing system to at best achieve some ++semblance of fairness across CPUs and can only maintain relatively low latency ++for tasks bound to the same CPUs, not across them. To increase said fairness ++and latency across CPUs, the advantage of local runqueue locking, which makes ++for better scalability, is lost due to having to grab multiple locks. ++ ++A significant feature of BFS is that all accounting is done purely based on CPU ++used and nowhere is sleep time used in any way to determine entitlement or ++interactivity. Interactivity "estimators" that use some kind of sleep/run ++algorithm are doomed to fail to detect all interactive tasks, and to falsely tag ++tasks that aren't interactive as being so. The reason for this is that it is ++close to impossible to determine that when a task is sleeping, whether it is ++doing it voluntarily, as in a userspace application waiting for input in the ++form of a mouse click or otherwise, or involuntarily, because it is waiting for ++another thread, process, I/O, kernel activity or whatever. Thus, such an ++estimator will introduce corner cases, and more heuristics will be required to ++cope with those corner cases, introducing more corner cases and failed ++interactivity detection and so on. Interactivity in BFS is built into the design ++by virtue of the fact that tasks that are waking up have not used up their quota ++of CPU time, and have earlier effective deadlines, thereby making it very likely ++they will preempt any CPU bound task of equivalent nice level. See below for ++more information on the virtual deadline mechanism. Even if they do not preempt ++a running task, because the rr interval is guaranteed to have a bound upper ++limit on how long a task will wait for, it will be scheduled within a timeframe ++that will not cause visible interface jitter. ++ ++ ++Design details. ++ ++Task insertion. ++ ++BFS inserts tasks into each relevant queue as an O(1) insertion into a double ++linked list. On insertion, *every* running queue is checked to see if the newly ++queued task can run on any idle queue, or preempt the lowest running task on the ++system. This is how the cross-CPU scheduling of BFS achieves significantly lower ++latency per extra CPU the system has. In this case the lookup is, in the worst ++case scenario, O(n) where n is the number of CPUs on the system. ++ ++Data protection. ++ ++BFS has one single lock protecting the process local data of every task in the ++global queue. Thus every insertion, removal and modification of task data in the ++global runqueue needs to grab the global lock. However, once a task is taken by ++a CPU, the CPU has its own local data copy of the running process' accounting ++information which only that CPU accesses and modifies (such as during a ++timer tick) thus allowing the accounting data to be updated lockless. Once a ++CPU has taken a task to run, it removes it from the global queue. Thus the ++global queue only ever has, at most, ++ ++ (number of tasks requesting cpu time) - (number of logical CPUs) + 1 ++ ++tasks in the global queue. This value is relevant for the time taken to look up ++tasks during scheduling. This will increase if many tasks with CPU affinity set ++in their policy to limit which CPUs they're allowed to run on if they outnumber ++the number of CPUs. The +1 is because when rescheduling a task, the CPU's ++currently running task is put back on the queue. Lookup will be described after ++the virtual deadline mechanism is explained. ++ ++Virtual deadline. ++ ++The key to achieving low latency, scheduling fairness, and "nice level" ++distribution in BFS is entirely in the virtual deadline mechanism. The one ++tunable in BFS is the rr_interval, or "round robin interval". This is the ++maximum time two SCHED_OTHER (or SCHED_NORMAL, the common scheduling policy) ++tasks of the same nice level will be running for, or looking at it the other ++way around, the longest duration two tasks of the same nice level will be ++delayed for. When a task requests cpu time, it is given a quota (time_slice) ++equal to the rr_interval and a virtual deadline. The virtual deadline is ++offset from the current time in jiffies by this equation: ++ ++ jiffies + (prio_ratio * rr_interval) ++ ++The prio_ratio is determined as a ratio compared to the baseline of nice -20 ++and increases by 10% per nice level. The deadline is a virtual one only in that ++no guarantee is placed that a task will actually be scheduled by this time, but ++it is used to compare which task should go next. There are three components to ++how a task is next chosen. First is time_slice expiration. If a task runs out ++of its time_slice, it is descheduled, the time_slice is refilled, and the ++deadline reset to that formula above. Second is sleep, where a task no longer ++is requesting CPU for whatever reason. The time_slice and deadline are _not_ ++adjusted in this case and are just carried over for when the task is next ++scheduled. Third is preemption, and that is when a newly waking task is deemed ++higher priority than a currently running task on any cpu by virtue of the fact ++that it has an earlier virtual deadline than the currently running task. The ++earlier deadline is the key to which task is next chosen for the first and ++second cases. Once a task is descheduled, it is put back on the queue, and an ++O(n) lookup of all queued-but-not-running tasks is done to determine which has ++the earliest deadline and that task is chosen to receive CPU next. ++ ++The CPU proportion of different nice tasks works out to be approximately the ++ ++ (prio_ratio difference)^2 ++ ++The reason it is squared is that a task's deadline does not change while it is ++running unless it runs out of time_slice. Thus, even if the time actually ++passes the deadline of another task that is queued, it will not get CPU time ++unless the current running task deschedules, and the time "base" (jiffies) is ++constantly moving. ++ ++Task lookup. ++ ++BFS has 103 priority queues. 100 of these are dedicated to the static priority ++of realtime tasks, and the remaining 3 are, in order of best to worst priority, ++SCHED_ISO (isochronous), SCHED_NORMAL, and SCHED_IDLEPRIO (idle priority ++scheduling). When a task of these priorities is queued, a bitmap of running ++priorities is set showing which of these priorities has tasks waiting for CPU ++time. When a CPU is made to reschedule, the lookup for the next task to get ++CPU time is performed in the following way: ++ ++First the bitmap is checked to see what static priority tasks are queued. If ++any realtime priorities are found, the corresponding queue is checked and the ++first task listed there is taken (provided CPU affinity is suitable) and lookup ++is complete. If the priority corresponds to a SCHED_ISO task, they are also ++taken in FIFO order (as they behave like SCHED_RR). If the priority corresponds ++to either SCHED_NORMAL or SCHED_IDLEPRIO, then the lookup becomes O(n). At this ++stage, every task in the runlist that corresponds to that priority is checked ++to see which has the earliest set deadline, and (provided it has suitable CPU ++affinity) it is taken off the runqueue and given the CPU. If a task has an ++expired deadline, it is taken and the rest of the lookup aborted (as they are ++chosen in FIFO order). ++ ++Thus, the lookup is O(n) in the worst case only, where n is as described ++earlier, as tasks may be chosen before the whole task list is looked over. ++ ++ ++Scalability. ++ ++The major limitations of BFS will be that of scalability, as the separate ++runqueue designs will have less lock contention as the number of CPUs rises. ++However they do not scale linearly even with separate runqueues as multiple ++runqueues will need to be locked concurrently on such designs to be able to ++achieve fair CPU balancing, to try and achieve some sort of nice-level fairness ++across CPUs, and to achieve low enough latency for tasks on a busy CPU when ++other CPUs would be more suited. BFS has the advantage that it requires no ++balancing algorithm whatsoever, as balancing occurs by proxy simply because ++all CPUs draw off the global runqueue, in priority and deadline order. Despite ++the fact that scalability is _not_ the prime concern of BFS, it both shows very ++good scalability to smaller numbers of CPUs and is likely a more scalable design ++at these numbers of CPUs. ++ ++It also has some very low overhead scalability features built into the design ++when it has been deemed their overhead is so marginal that they're worth adding. ++The first is the local copy of the running process' data to the CPU it's running ++on to allow that data to be updated lockless where possible. Then there is ++deference paid to the last CPU a task was running on, by trying that CPU first ++when looking for an idle CPU to use the next time it's scheduled. Finally there ++is the notion of "sticky" tasks that are flagged when they are involuntarily ++descheduled, meaning they still want further CPU time. This sticky flag is ++used to bias heavily against those tasks being scheduled on a different CPU ++unless that CPU would be otherwise idle. When a cpu frequency governor is used ++that scales with CPU load, such as ondemand, sticky tasks are not scheduled ++on a different CPU at all, preferring instead to go idle. This means the CPU ++they were bound to is more likely to increase its speed while the other CPU ++will go idle, thus speeding up total task execution time and likely decreasing ++power usage. This is the only scenario where BFS will allow a CPU to go idle ++in preference to scheduling a task on the earliest available spare CPU. ++ ++The real cost of migrating a task from one CPU to another is entirely dependant ++on the cache footprint of the task, how cache intensive the task is, how long ++it's been running on that CPU to take up the bulk of its cache, how big the CPU ++cache is, how fast and how layered the CPU cache is, how fast a context switch ++is... and so on. In other words, it's close to random in the real world where we ++do more than just one sole workload. The only thing we can be sure of is that ++it's not free. So BFS uses the principle that an idle CPU is a wasted CPU and ++utilising idle CPUs is more important than cache locality, and cache locality ++only plays a part after that. ++ ++When choosing an idle CPU for a waking task, the cache locality is determined ++according to where the task last ran and then idle CPUs are ranked from best ++to worst to choose the most suitable idle CPU based on cache locality, NUMA ++node locality and hyperthread sibling business. They are chosen in the ++following preference (if idle): ++ ++* Same core, idle or busy cache, idle threads ++* Other core, same cache, idle or busy cache, idle threads. ++* Same node, other CPU, idle cache, idle threads. ++* Same node, other CPU, busy cache, idle threads. ++* Same core, busy threads. ++* Other core, same cache, busy threads. ++* Same node, other CPU, busy threads. ++* Other node, other CPU, idle cache, idle threads. ++* Other node, other CPU, busy cache, idle threads. ++* Other node, other CPU, busy threads. ++ ++This shows the SMT or "hyperthread" awareness in the design as well which will ++choose a real idle core first before a logical SMT sibling which already has ++tasks on the physical CPU. ++ ++Early benchmarking of BFS suggested scalability dropped off at the 16 CPU mark. ++However this benchmarking was performed on an earlier design that was far less ++scalable than the current one so it's hard to know how scalable it is in terms ++of both CPUs (due to the global runqueue) and heavily loaded machines (due to ++O(n) lookup) at this stage. Note that in terms of scalability, the number of ++_logical_ CPUs matters, not the number of _physical_ CPUs. Thus, a dual (2x) ++quad core (4X) hyperthreaded (2X) machine is effectively a 16X. Newer benchmark ++results are very promising indeed, without needing to tweak any knobs, features ++or options. Benchmark contributions are most welcome. ++ ++ ++Features ++ ++As the initial prime target audience for BFS was the average desktop user, it ++was designed to not need tweaking, tuning or have features set to obtain benefit ++from it. Thus the number of knobs and features has been kept to an absolute ++minimum and should not require extra user input for the vast majority of cases. ++There are precisely 2 tunables, and 2 extra scheduling policies. The rr_interval ++and iso_cpu tunables, and the SCHED_ISO and SCHED_IDLEPRIO policies. In addition ++to this, BFS also uses sub-tick accounting. What BFS does _not_ now feature is ++support for CGROUPS. The average user should neither need to know what these ++are, nor should they need to be using them to have good desktop behaviour. ++ ++rr_interval ++ ++There is only one "scheduler" tunable, the round robin interval. This can be ++accessed in ++ ++ /proc/sys/kernel/rr_interval ++ ++The value is in milliseconds, and the default value is set to 6ms. Valid values ++are from 1 to 1000. Decreasing the value will decrease latencies at the cost of ++decreasing throughput, while increasing it will improve throughput, but at the ++cost of worsening latencies. The accuracy of the rr interval is limited by HZ ++resolution of the kernel configuration. Thus, the worst case latencies are ++usually slightly higher than this actual value. BFS uses "dithering" to try and ++minimise the effect the Hz limitation has. The default value of 6 is not an ++arbitrary one. It is based on the fact that humans can detect jitter at ++approximately 7ms, so aiming for much lower latencies is pointless under most ++circumstances. It is worth noting this fact when comparing the latency ++performance of BFS to other schedulers. Worst case latencies being higher than ++7ms are far worse than average latencies not being in the microsecond range. ++Experimentation has shown that rr intervals being increased up to 300 can ++improve throughput but beyond that, scheduling noise from elsewhere prevents ++further demonstrable throughput. ++ ++Isochronous scheduling. ++ ++Isochronous scheduling is a unique scheduling policy designed to provide ++near-real-time performance to unprivileged (ie non-root) users without the ++ability to starve the machine indefinitely. Isochronous tasks (which means ++"same time") are set using, for example, the schedtool application like so: ++ ++ schedtool -I -e amarok ++ ++This will start the audio application "amarok" as SCHED_ISO. How SCHED_ISO works ++is that it has a priority level between true realtime tasks and SCHED_NORMAL ++which would allow them to preempt all normal tasks, in a SCHED_RR fashion (ie, ++if multiple SCHED_ISO tasks are running, they purely round robin at rr_interval ++rate). However if ISO tasks run for more than a tunable finite amount of time, ++they are then demoted back to SCHED_NORMAL scheduling. This finite amount of ++time is the percentage of _total CPU_ available across the machine, configurable ++as a percentage in the following "resource handling" tunable (as opposed to a ++scheduler tunable): ++ ++ /proc/sys/kernel/iso_cpu ++ ++and is set to 70% by default. It is calculated over a rolling 5 second average ++Because it is the total CPU available, it means that on a multi CPU machine, it ++is possible to have an ISO task running as realtime scheduling indefinitely on ++just one CPU, as the other CPUs will be available. Setting this to 100 is the ++equivalent of giving all users SCHED_RR access and setting it to 0 removes the ++ability to run any pseudo-realtime tasks. ++ ++A feature of BFS is that it detects when an application tries to obtain a ++realtime policy (SCHED_RR or SCHED_FIFO) and the caller does not have the ++appropriate privileges to use those policies. When it detects this, it will ++give the task SCHED_ISO policy instead. Thus it is transparent to the user. ++Because some applications constantly set their policy as well as their nice ++level, there is potential for them to undo the override specified by the user ++on the command line of setting the policy to SCHED_ISO. To counter this, once ++a task has been set to SCHED_ISO policy, it needs superuser privileges to set ++it back to SCHED_NORMAL. This will ensure the task remains ISO and all child ++processes and threads will also inherit the ISO policy. ++ ++Idleprio scheduling. ++ ++Idleprio scheduling is a scheduling policy designed to give out CPU to a task ++_only_ when the CPU would be otherwise idle. The idea behind this is to allow ++ultra low priority tasks to be run in the background that have virtually no ++effect on the foreground tasks. This is ideally suited to distributed computing ++clients (like setiathome, folding, mprime etc) but can also be used to start ++a video encode or so on without any slowdown of other tasks. To avoid this ++policy from grabbing shared resources and holding them indefinitely, if it ++detects a state where the task is waiting on I/O, the machine is about to ++suspend to ram and so on, it will transiently schedule them as SCHED_NORMAL. As ++per the Isochronous task management, once a task has been scheduled as IDLEPRIO, ++it cannot be put back to SCHED_NORMAL without superuser privileges. Tasks can ++be set to start as SCHED_IDLEPRIO with the schedtool command like so: ++ ++ schedtool -D -e ./mprime ++ ++Subtick accounting. ++ ++It is surprisingly difficult to get accurate CPU accounting, and in many cases, ++the accounting is done by simply determining what is happening at the precise ++moment a timer tick fires off. This becomes increasingly inaccurate as the ++timer tick frequency (HZ) is lowered. It is possible to create an application ++which uses almost 100% CPU, yet by being descheduled at the right time, records ++zero CPU usage. While the main problem with this is that there are possible ++security implications, it is also difficult to determine how much CPU a task ++really does use. BFS tries to use the sub-tick accounting from the TSC clock, ++where possible, to determine real CPU usage. This is not entirely reliable, but ++is far more likely to produce accurate CPU usage data than the existing designs ++and will not show tasks as consuming no CPU usage when they actually are. Thus, ++the amount of CPU reported as being used by BFS will more accurately represent ++how much CPU the task itself is using (as is shown for example by the 'time' ++application), so the reported values may be quite different to other schedulers. ++Values reported as the 'load' are more prone to problems with this design, but ++per process values are closer to real usage. When comparing throughput of BFS ++to other designs, it is important to compare the actual completed work in terms ++of total wall clock time taken and total work done, rather than the reported ++"cpu usage". ++ ++ ++Con Kolivas Tue, 5 Apr 2011 +Index: linux-3.12-ck2/Documentation/sysctl/kernel.txt +=================================================================== +--- linux-3.12-ck2.orig/Documentation/sysctl/kernel.txt 2013-12-03 20:12:21.186148542 +1100 ++++ linux-3.12-ck2/Documentation/sysctl/kernel.txt 2013-12-03 20:12:21.155148930 +1100 +@@ -33,6 +33,7 @@ show up in /proc/sys/kernel: + - domainname + - hostname + - hotplug ++- iso_cpu + - kptr_restrict + - kstack_depth_to_print [ X86 only ] + - l2cr [ PPC only ] +@@ -60,6 +61,7 @@ show up in /proc/sys/kernel: + - randomize_va_space + - real-root-dev ==> Documentation/initrd.txt + - reboot-cmd [ SPARC only ] ++- rr_interval + - rtsig-max + - rtsig-nr + - sem +@@ -307,6 +309,16 @@ kernel stack. + + ============================================================== + ++iso_cpu: (BFS CPU scheduler only). ++ ++This sets the percentage cpu that the unprivileged SCHED_ISO tasks can ++run effectively at realtime priority, averaged over a rolling five ++seconds over the -whole- system, meaning all cpus. ++ ++Set to 70 (percent) by default. ++ ++============================================================== ++ + l2cr: (PPC only) + + This flag controls the L2 cache of G3 processor boards. If +@@ -565,6 +577,20 @@ rebooting. ??? + + ============================================================== + ++rr_interval: (BFS CPU scheduler only) ++ ++This is the smallest duration that any cpu process scheduling unit ++will run for. Increasing this value can increase throughput of cpu ++bound tasks substantially but at the expense of increased latencies ++overall. Conversely decreasing it will decrease average and maximum ++latencies but at the expense of throughput. This value is in ++milliseconds and the default value chosen depends on the number of ++cpus available at scheduler initialisation with a minimum of 6. ++ ++Valid values are from 1-1000. ++ ++============================================================== ++ + rtsig-max & rtsig-nr: + + The file rtsig-max can be used to tune the maximum number +Index: linux-3.12-ck2/fs/proc/base.c +=================================================================== +--- linux-3.12-ck2.orig/fs/proc/base.c 2013-12-03 20:12:21.186148542 +1100 ++++ linux-3.12-ck2/fs/proc/base.c 2013-12-03 20:12:21.157148905 +1100 +@@ -339,7 +339,7 @@ static int proc_pid_stack(struct seq_fil + static int proc_pid_schedstat(struct task_struct *task, char *buffer) + { + return sprintf(buffer, "%llu %llu %lu\n", +- (unsigned long long)task->se.sum_exec_runtime, ++ (unsigned long long)tsk_seruntime(task), + (unsigned long long)task->sched_info.run_delay, + task->sched_info.pcount); + } +Index: linux-3.12-ck2/include/linux/init_task.h +=================================================================== +--- linux-3.12-ck2.orig/include/linux/init_task.h 2013-12-03 20:12:21.186148542 +1100 ++++ linux-3.12-ck2/include/linux/init_task.h 2013-12-03 20:12:21.157148905 +1100 +@@ -152,12 +152,70 @@ extern struct task_group root_task_group + # define INIT_VTIME(tsk) + #endif + +-#define INIT_TASK_COMM "swapper" +- + /* + * INIT_TASK is used to set up the first task table, touch at + * your own risk!. Base=0, limit=0x1fffff (=2MB) + */ ++#ifdef CONFIG_SCHED_BFS ++#define INIT_TASK_COMM "BFS" ++#define INIT_TASK(tsk) \ ++{ \ ++ .state = 0, \ ++ .stack = &init_thread_info, \ ++ .usage = ATOMIC_INIT(2), \ ++ .flags = PF_KTHREAD, \ ++ .prio = NORMAL_PRIO, \ ++ .static_prio = MAX_PRIO-20, \ ++ .normal_prio = NORMAL_PRIO, \ ++ .deadline = 0, \ ++ .policy = SCHED_NORMAL, \ ++ .cpus_allowed = CPU_MASK_ALL, \ ++ .mm = NULL, \ ++ .active_mm = &init_mm, \ ++ .run_list = LIST_HEAD_INIT(tsk.run_list), \ ++ .time_slice = HZ, \ ++ .tasks = LIST_HEAD_INIT(tsk.tasks), \ ++ INIT_PUSHABLE_TASKS(tsk) \ ++ .ptraced = LIST_HEAD_INIT(tsk.ptraced), \ ++ .ptrace_entry = LIST_HEAD_INIT(tsk.ptrace_entry), \ ++ .real_parent = &tsk, \ ++ .parent = &tsk, \ ++ .children = LIST_HEAD_INIT(tsk.children), \ ++ .sibling = LIST_HEAD_INIT(tsk.sibling), \ ++ .group_leader = &tsk, \ ++ RCU_POINTER_INITIALIZER(real_cred, &init_cred), \ ++ RCU_POINTER_INITIALIZER(cred, &init_cred), \ ++ .comm = INIT_TASK_COMM, \ ++ .thread = INIT_THREAD, \ ++ .fs = &init_fs, \ ++ .files = &init_files, \ ++ .signal = &init_signals, \ ++ .sighand = &init_sighand, \ ++ .nsproxy = &init_nsproxy, \ ++ .pending = { \ ++ .list = LIST_HEAD_INIT(tsk.pending.list), \ ++ .signal = {{0}}}, \ ++ .blocked = {{0}}, \ ++ .alloc_lock = __SPIN_LOCK_UNLOCKED(tsk.alloc_lock), \ ++ .journal_info = NULL, \ ++ .cpu_timers = INIT_CPU_TIMERS(tsk.cpu_timers), \ ++ .pi_lock = __RAW_SPIN_LOCK_UNLOCKED(tsk.pi_lock), \ ++ .timer_slack_ns = 50000, /* 50 usec default slack */ \ ++ .pids = { \ ++ [PIDTYPE_PID] = INIT_PID_LINK(PIDTYPE_PID), \ ++ [PIDTYPE_PGID] = INIT_PID_LINK(PIDTYPE_PGID), \ ++ [PIDTYPE_SID] = INIT_PID_LINK(PIDTYPE_SID), \ ++ }, \ ++ INIT_IDS \ ++ INIT_PERF_EVENTS(tsk) \ ++ INIT_TRACE_IRQFLAGS \ ++ INIT_LOCKDEP \ ++ INIT_FTRACE_GRAPH \ ++ INIT_TRACE_RECURSION \ ++ INIT_TASK_RCU_PREEMPT(tsk) \ ++} ++#else /* CONFIG_SCHED_BFS */ ++#define INIT_TASK_COMM "swapper" + #define INIT_TASK(tsk) \ + { \ + .state = 0, \ +@@ -223,7 +281,7 @@ extern struct task_group root_task_group + INIT_CPUSET_SEQ \ + INIT_VTIME(tsk) \ + } +- ++#endif /* CONFIG_SCHED_BFS */ + + #define INIT_CPU_TIMERS(cpu_timers) \ + { \ +Index: linux-3.12-ck2/include/linux/ioprio.h +=================================================================== +--- linux-3.12-ck2.orig/include/linux/ioprio.h 2013-12-03 20:12:21.186148542 +1100 ++++ linux-3.12-ck2/include/linux/ioprio.h 2013-12-03 20:12:21.158148892 +1100 +@@ -52,6 +52,8 @@ enum { + */ + static inline int task_nice_ioprio(struct task_struct *task) + { ++ if (iso_task(task)) ++ return 0; + return (task_nice(task) + 20) / 5; + } + +Index: linux-3.12-ck2/include/linux/sched.h +=================================================================== +--- linux-3.12-ck2.orig/include/linux/sched.h 2013-12-03 20:12:21.186148542 +1100 ++++ linux-3.12-ck2/include/linux/sched.h 2013-12-03 20:12:21.159148880 +1100 +@@ -221,8 +221,6 @@ extern asmlinkage void schedule_tail(str + extern void init_idle(struct task_struct *idle, int cpu); + extern void init_idle_bootup_task(struct task_struct *idle); + +-extern int runqueue_is_locked(int cpu); +- + #if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON) + extern void nohz_balance_enter_idle(int cpu); + extern void set_cpu_sd_state_idle(void); +@@ -1023,20 +1021,39 @@ struct task_struct { + unsigned int flags; /* per process flags, defined below */ + unsigned int ptrace; + +-#ifdef CONFIG_SMP ++#if defined(CONFIG_SMP) || defined(CONFIG_SCHED_BFS) + struct llist_node wake_entry; + int on_cpu; ++#endif ++#ifdef CONFIG_SMP + struct task_struct *last_wakee; + unsigned long wakee_flips; + unsigned long wakee_flip_decay_ts; + #endif ++#ifndef CONFIG_SCHED_BFS + int on_rq; ++#endif + + int prio, static_prio, normal_prio; + unsigned int rt_priority; ++#ifdef CONFIG_SCHED_BFS ++ int time_slice; ++ u64 deadline; ++ struct list_head run_list; ++ u64 last_ran; ++ u64 sched_time; /* sched_clock time spent running */ ++#ifdef CONFIG_SMP ++ bool sticky; /* Soft affined flag */ ++#endif ++#ifdef CONFIG_HOTPLUG_CPU ++ bool zerobound; /* Bound to CPU0 for hotplug */ ++#endif ++ unsigned long rt_timeout; ++#else /* CONFIG_SCHED_BFS */ + const struct sched_class *sched_class; + struct sched_entity se; + struct sched_rt_entity rt; ++#endif + #ifdef CONFIG_CGROUP_SCHED + struct task_group *sched_task_group; + #endif +@@ -1150,6 +1167,9 @@ struct task_struct { + int __user *clear_child_tid; /* CLONE_CHILD_CLEARTID */ + + cputime_t utime, stime, utimescaled, stimescaled; ++#ifdef CONFIG_SCHED_BFS ++ unsigned long utime_pc, stime_pc; ++#endif + cputime_t gtime; + #ifndef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE + struct cputime prev_cputime; +@@ -1409,6 +1429,64 @@ struct task_struct { + #endif + }; + ++#ifdef CONFIG_SCHED_BFS ++bool grunqueue_is_locked(void); ++void grq_unlock_wait(void); ++void cpu_scaling(int cpu); ++void cpu_nonscaling(int cpu); ++bool above_background_load(void); ++#define tsk_seruntime(t) ((t)->sched_time) ++#define tsk_rttimeout(t) ((t)->rt_timeout) ++ ++static inline void tsk_cpus_current(struct task_struct *p) ++{ ++} ++ ++static inline int runqueue_is_locked(int cpu) ++{ ++ return grunqueue_is_locked(); ++} ++ ++void print_scheduler_version(void); ++ ++static inline bool iso_task(struct task_struct *p) ++{ ++ return (p->policy == SCHED_ISO); ++} ++#else /* CFS */ ++extern int runqueue_is_locked(int cpu); ++static inline void cpu_scaling(int cpu) ++{ ++} ++ ++static inline void cpu_nonscaling(int cpu) ++{ ++} ++#define tsk_seruntime(t) ((t)->se.sum_exec_runtime) ++#define tsk_rttimeout(t) ((t)->rt.timeout) ++ ++static inline void tsk_cpus_current(struct task_struct *p) ++{ ++ p->nr_cpus_allowed = current->nr_cpus_allowed; ++} ++ ++static inline void print_scheduler_version(void) ++{ ++ printk(KERN_INFO"CFS CPU scheduler.\n"); ++} ++ ++static inline bool iso_task(struct task_struct *p) ++{ ++ return false; ++} ++ ++/* Anyone feel like implementing this? */ ++static inline bool above_background_load(void) ++{ ++ return false; ++} ++#endif /* CONFIG_SCHED_BFS */ ++ + /* Future-safe accessor for struct task_struct's cpus_allowed. */ + #define tsk_cpus_allowed(tsk) (&(tsk)->cpus_allowed) + +@@ -1840,7 +1918,7 @@ extern unsigned long long + task_sched_runtime(struct task_struct *task); + + /* sched_exec is called by processes performing an exec */ +-#ifdef CONFIG_SMP ++#if defined(CONFIG_SMP) && !defined(CONFIG_SCHED_BFS) + extern void sched_exec(void); + #else + #define sched_exec() {} +@@ -2554,7 +2632,7 @@ static inline unsigned int task_cpu(cons + return 0; + } + +-static inline void set_task_cpu(struct task_struct *p, unsigned int cpu) ++static inline void set_task_cpu(struct task_struct *p, int cpu) + { + } + +Index: linux-3.12-ck2/init/Kconfig +=================================================================== +--- linux-3.12-ck2.orig/init/Kconfig 2013-12-03 20:12:21.186148542 +1100 ++++ linux-3.12-ck2/init/Kconfig 2013-12-03 20:12:21.160148867 +1100 +@@ -28,6 +28,20 @@ config BUILDTIME_EXTABLE_SORT + + menu "General setup" + ++config SCHED_BFS ++ bool "BFS cpu scheduler" ++ ---help--- ++ The Brain Fuck CPU Scheduler for excellent interactivity and ++ responsiveness on the desktop and solid scalability on normal ++ hardware and commodity servers. Not recommended for 4096 CPUs. ++ ++ Currently incompatible with the Group CPU scheduler, and RCU TORTURE ++ TEST so these options are disabled. ++ ++ Say Y here. ++ default y ++ ++ + config BROKEN + bool + +@@ -331,7 +345,7 @@ choice + # Kind of a stub config for the pure tick based cputime accounting + config TICK_CPU_ACCOUNTING + bool "Simple tick based cputime accounting" +- depends on !S390 && !NO_HZ_FULL ++ depends on !S390 && !NO_HZ_FULL && !SCHED_BFS + help + This is the basic tick based cputime accounting that maintains + statistics about user, system and idle time spent on per jiffies +@@ -354,7 +368,7 @@ config VIRT_CPU_ACCOUNTING_NATIVE + + config VIRT_CPU_ACCOUNTING_GEN + bool "Full dynticks CPU time accounting" +- depends on HAVE_CONTEXT_TRACKING && 64BIT ++ depends on HAVE_CONTEXT_TRACKING && 64BIT && !SCHED_BFS + select VIRT_CPU_ACCOUNTING + select CONTEXT_TRACKING + help +@@ -510,7 +524,7 @@ config CONTEXT_TRACKING + + config RCU_USER_QS + bool "Consider userspace as in RCU extended quiescent state" +- depends on HAVE_CONTEXT_TRACKING && SMP ++ depends on HAVE_CONTEXT_TRACKING && SMP && !SCHED_BFS + select CONTEXT_TRACKING + help + This option sets hooks on kernel / userspace boundaries and +@@ -695,7 +709,7 @@ config RCU_BOOST_DELAY + + config RCU_NOCB_CPU + bool "Offload RCU callback processing from boot-selected CPUs" +- depends on TREE_RCU || TREE_PREEMPT_RCU ++ depends on (TREE_RCU || TREE_PREEMPT_RCU) && !SCHED_BFS + default n + help + Use this option to reduce OS jitter for aggressive HPC or +@@ -852,6 +866,7 @@ config NUMA_BALANCING + depends on ARCH_SUPPORTS_NUMA_BALANCING + depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY + depends on SMP && NUMA && MIGRATION ++ depends on !SCHED_BFS + help + This option adds support for automatic NUMA aware memory/task placement. + The mechanism is quite primitive and is based on migrating memory when +@@ -914,6 +929,7 @@ config PROC_PID_CPUSET + + config CGROUP_CPUACCT + bool "Simple CPU accounting cgroup subsystem" ++ depends on !SCHED_BFS + help + Provides a simple Resource Controller for monitoring the + total CPU consumed by the tasks in a cgroup. +@@ -1016,6 +1032,7 @@ config CGROUP_PERF + + menuconfig CGROUP_SCHED + bool "Group CPU scheduler" ++ depends on !SCHED_BFS + default n + help + This feature lets CPU scheduler recognize task groups and control CPU +@@ -1167,6 +1184,7 @@ config UIDGID_STRICT_TYPE_CHECKS + + config SCHED_AUTOGROUP + bool "Automatic process group scheduling" ++ depends on !SCHED_BFS + select EVENTFD + select CGROUPS + select CGROUP_SCHED +@@ -1567,38 +1585,8 @@ config COMPAT_BRK + + On non-ancient distros (post-2000 ones) N is usually a safe choice. + +-choice +- prompt "Choose SLAB allocator" +- default SLUB +- help +- This option allows to select a slab allocator. +- +-config SLAB +- bool "SLAB" +- help +- The regular slab allocator that is established and known to work +- well in all environments. It organizes cache hot objects in +- per cpu and per node queues. +- + config SLUB +- bool "SLUB (Unqueued Allocator)" +- help +- SLUB is a slab allocator that minimizes cache line usage +- instead of managing queues of cached objects (SLAB approach). +- Per cpu caching is realized using slabs of objects instead +- of queues of objects. SLUB can use memory efficiently +- and has enhanced diagnostics. SLUB is the default choice for +- a slab allocator. +- +-config SLOB +- depends on EXPERT +- bool "SLOB (Simple Allocator)" +- help +- SLOB replaces the stock allocator with a drastically simpler +- allocator. SLOB is generally more space efficient but +- does not perform as well on large systems. +- +-endchoice ++ def_bool y + + config SLUB_CPU_PARTIAL + default y +Index: linux-3.12-ck2/init/main.c +=================================================================== +--- linux-3.12-ck2.orig/init/main.c 2013-12-03 20:12:21.186148542 +1100 ++++ linux-3.12-ck2/init/main.c 2013-12-03 20:12:21.161148855 +1100 +@@ -704,7 +704,6 @@ int __init_or_module do_one_initcall(ini + return ret; + } + +- + extern initcall_t __initcall_start[]; + extern initcall_t __initcall0_start[]; + extern initcall_t __initcall1_start[]; +@@ -825,6 +824,8 @@ static int __ref kernel_init(void *unuse + + flush_delayed_fput(); + ++ print_scheduler_version(); ++ + if (ramdisk_execute_command) { + if (!run_init_process(ramdisk_execute_command)) + return 0; +Index: linux-3.12-ck2/kernel/delayacct.c +=================================================================== +--- linux-3.12-ck2.orig/kernel/delayacct.c 2013-12-03 20:12:21.186148542 +1100 ++++ linux-3.12-ck2/kernel/delayacct.c 2013-12-03 20:12:21.162148842 +1100 +@@ -133,7 +133,7 @@ int __delayacct_add_tsk(struct taskstats + */ + t1 = tsk->sched_info.pcount; + t2 = tsk->sched_info.run_delay; +- t3 = tsk->se.sum_exec_runtime; ++ t3 = tsk_seruntime(tsk); + + d->cpu_count += t1; + +Index: linux-3.12-ck2/kernel/exit.c +=================================================================== +--- linux-3.12-ck2.orig/kernel/exit.c 2013-12-03 20:12:21.186148542 +1100 ++++ linux-3.12-ck2/kernel/exit.c 2013-12-03 20:12:21.163148830 +1100 +@@ -135,7 +135,7 @@ static void __exit_signal(struct task_st + sig->inblock += task_io_get_inblock(tsk); + sig->oublock += task_io_get_oublock(tsk); + task_io_accounting_add(&sig->ioac, &tsk->ioac); +- sig->sum_sched_runtime += tsk->se.sum_exec_runtime; ++ sig->sum_sched_runtime += tsk_seruntime(tsk); + } + + sig->nr_threads--; +Index: linux-3.12-ck2/kernel/posix-cpu-timers.c +=================================================================== +--- linux-3.12-ck2.orig/kernel/posix-cpu-timers.c 2013-12-03 20:12:21.186148542 +1100 ++++ linux-3.12-ck2/kernel/posix-cpu-timers.c 2013-12-03 20:12:21.163148830 +1100 +@@ -435,11 +435,11 @@ void posix_cpu_timers_exit(struct task_s + { + cputime_t utime, stime; + +- add_device_randomness((const void*) &tsk->se.sum_exec_runtime, ++ add_device_randomness((const void*) &tsk_seruntime(tsk), + sizeof(unsigned long long)); + task_cputime(tsk, &utime, &stime); + cleanup_timers(tsk->cpu_timers, +- utime, stime, tsk->se.sum_exec_runtime); ++ utime, stime, tsk_seruntime(tsk)); + + } + void posix_cpu_timers_exit_group(struct task_struct *tsk) +@@ -450,7 +450,7 @@ void posix_cpu_timers_exit_group(struct + task_cputime(tsk, &utime, &stime); + cleanup_timers(tsk->signal->cpu_timers, + utime + sig->utime, stime + sig->stime, +- tsk->se.sum_exec_runtime + sig->sum_sched_runtime); ++ tsk_seruntime(tsk) + sig->sum_sched_runtime); + } + + static void clear_dead_task(struct k_itimer *itimer, unsigned long long now) +@@ -905,7 +905,7 @@ static void check_thread_timers(struct t + tsk_expires->virt_exp = expires_to_cputime(expires); + + tsk_expires->sched_exp = check_timers_list(++timers, firing, +- tsk->se.sum_exec_runtime); ++ tsk_seruntime(tsk)); + + /* + * Check for the special case thread timers. +@@ -916,7 +916,7 @@ static void check_thread_timers(struct t + ACCESS_ONCE(sig->rlim[RLIMIT_RTTIME].rlim_max); + + if (hard != RLIM_INFINITY && +- tsk->rt.timeout > DIV_ROUND_UP(hard, USEC_PER_SEC/HZ)) { ++ tsk_rttimeout(tsk) > DIV_ROUND_UP(hard, USEC_PER_SEC/HZ)) { + /* + * At the hard limit, we just die. + * No need to calculate anything else now. +@@ -924,7 +924,7 @@ static void check_thread_timers(struct t + __group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk); + return; + } +- if (tsk->rt.timeout > DIV_ROUND_UP(soft, USEC_PER_SEC/HZ)) { ++ if (tsk_rttimeout(tsk) > DIV_ROUND_UP(soft, USEC_PER_SEC/HZ)) { + /* + * At the soft limit, send a SIGXCPU every second. + */ +@@ -1167,7 +1167,7 @@ static inline int fastpath_timer_check(s + struct task_cputime task_sample = { + .utime = utime, + .stime = stime, +- .sum_exec_runtime = tsk->se.sum_exec_runtime ++ .sum_exec_runtime = tsk_seruntime(tsk) + }; + + if (task_cputime_expired(&task_sample, &tsk->cputime_expires)) +Index: linux-3.12-ck2/kernel/sysctl.c +=================================================================== +--- linux-3.12-ck2.orig/kernel/sysctl.c 2013-12-03 20:12:21.186148542 +1100 ++++ linux-3.12-ck2/kernel/sysctl.c 2013-12-03 20:12:21.164148817 +1100 +@@ -127,7 +127,12 @@ static int __maybe_unused one = 1; + static int __maybe_unused two = 2; + static int __maybe_unused three = 3; + static unsigned long one_ul = 1; +-static int one_hundred = 100; ++static int __maybe_unused one_hundred = 100; ++#ifdef CONFIG_SCHED_BFS ++extern int rr_interval; ++extern int sched_iso_cpu; ++static int __read_mostly one_thousand = 1000; ++#endif + #ifdef CONFIG_PRINTK + static int ten_thousand = 10000; + #endif +@@ -255,7 +260,7 @@ static struct ctl_table sysctl_base_tabl + { } + }; + +-#ifdef CONFIG_SCHED_DEBUG ++#if defined(CONFIG_SCHED_DEBUG) && !defined(CONFIG_SCHED_BFS) + static int min_sched_granularity_ns = 100000; /* 100 usecs */ + static int max_sched_granularity_ns = NSEC_PER_SEC; /* 1 second */ + static int min_wakeup_granularity_ns; /* 0 usecs */ +@@ -272,6 +277,7 @@ static int max_extfrag_threshold = 1000; + #endif + + static struct ctl_table kern_table[] = { ++#ifndef CONFIG_SCHED_BFS + { + .procname = "sched_child_runs_first", + .data = &sysctl_sched_child_runs_first, +@@ -435,6 +441,7 @@ static struct ctl_table kern_table[] = { + .extra1 = &one, + }, + #endif ++#endif /* !CONFIG_SCHED_BFS */ + #ifdef CONFIG_PROVE_LOCKING + { + .procname = "prove_locking", +@@ -913,6 +920,26 @@ static struct ctl_table kern_table[] = { + .proc_handler = proc_dointvec, + }, + #endif ++#ifdef CONFIG_SCHED_BFS ++ { ++ .procname = "rr_interval", ++ .data = &rr_interval, ++ .maxlen = sizeof (int), ++ .mode = 0644, ++ .proc_handler = &proc_dointvec_minmax, ++ .extra1 = &one, ++ .extra2 = &one_thousand, ++ }, ++ { ++ .procname = "iso_cpu", ++ .data = &sched_iso_cpu, ++ .maxlen = sizeof (int), ++ .mode = 0644, ++ .proc_handler = &proc_dointvec_minmax, ++ .extra1 = &zero, ++ .extra2 = &one_hundred, ++ }, ++#endif + #if defined(CONFIG_S390) && defined(CONFIG_SMP) + { + .procname = "spin_retry", +Index: linux-3.12-ck2/lib/Kconfig.debug +=================================================================== +--- linux-3.12-ck2.orig/lib/Kconfig.debug 2013-12-03 20:12:21.186148542 +1100 ++++ linux-3.12-ck2/lib/Kconfig.debug 2013-12-03 20:12:21.165148805 +1100 +@@ -1125,7 +1125,7 @@ config SPARSE_RCU_POINTER + + config RCU_TORTURE_TEST + tristate "torture tests for RCU" +- depends on DEBUG_KERNEL ++ depends on DEBUG_KERNEL && !SCHED_BFS + default n + help + This option provides a kernel module that runs torture tests +Index: linux-3.12-ck2/include/linux/jiffies.h +=================================================================== +--- linux-3.12-ck2.orig/include/linux/jiffies.h 2013-12-03 20:12:21.186148542 +1100 ++++ linux-3.12-ck2/include/linux/jiffies.h 2013-12-03 20:12:21.166148792 +1100 +@@ -163,7 +163,7 @@ static inline u64 get_jiffies_64(void) + * Have the 32 bit jiffies value wrap 5 minutes after boot + * so jiffies wrap bugs show up earlier. + */ +-#define INITIAL_JIFFIES ((unsigned long)(unsigned int) (-300*HZ)) ++#define INITIAL_JIFFIES ((unsigned long)(unsigned int) (-10*HZ)) + + /* + * Change timeval to jiffies, trying to avoid the +Index: linux-3.12-ck2/drivers/cpufreq/cpufreq.c +=================================================================== +--- linux-3.12-ck2.orig/drivers/cpufreq/cpufreq.c 2013-12-03 20:12:21.186148542 +1100 ++++ linux-3.12-ck2/drivers/cpufreq/cpufreq.c 2013-12-03 20:12:21.167148780 +1100 +@@ -25,6 +25,7 @@ + #include + #include + #include ++#include + #include + #include + #include +@@ -1686,6 +1687,12 @@ int __cpufreq_driver_target(struct cpufr + + if (cpufreq_driver->target) + retval = cpufreq_driver->target(policy, target_freq, relation); ++ if (likely(retval != -EINVAL)) { ++ if (target_freq == policy->max) ++ cpu_nonscaling(policy->cpu); ++ else ++ cpu_scaling(policy->cpu); ++ } + + return retval; + } +Index: linux-3.12-ck2/drivers/cpufreq/cpufreq_ondemand.c +=================================================================== +--- linux-3.12-ck2.orig/drivers/cpufreq/cpufreq_ondemand.c 2013-12-03 20:12:21.186148542 +1100 ++++ linux-3.12-ck2/drivers/cpufreq/cpufreq_ondemand.c 2013-12-03 20:12:21.168148767 +1100 +@@ -19,7 +19,7 @@ + #include "cpufreq_governor.h" + + /* On-demand governor macros */ +-#define DEF_FREQUENCY_UP_THRESHOLD (80) ++#define DEF_FREQUENCY_UP_THRESHOLD (63) + #define DEF_SAMPLING_DOWN_FACTOR (1) + #define MAX_SAMPLING_DOWN_FACTOR (100000) + #define MICRO_FREQUENCY_UP_THRESHOLD (95) +@@ -148,7 +148,7 @@ static void dbs_freq_increase(struct cpu + } + + /* +- * Every sampling_rate, we check, if current idle time is less than 20% ++ * Every sampling_rate, we check, if current idle time is less than 37% + * (default), then we try to increase frequency. Else, we adjust the frequency + * proportional to load. + */ +Index: linux-3.12-ck2/kernel/sched/bfs.c +=================================================================== +--- /dev/null 1970-01-01 00:00:00.000000000 +0000 ++++ linux-3.12-ck2/kernel/sched/bfs.c 2013-12-03 20:12:21.172148717 +1100 +@@ -0,0 +1,7494 @@ ++/* ++ * kernel/sched/bfs.c, was kernel/sched.c ++ * ++ * Kernel scheduler and related syscalls ++ * ++ * Copyright (C) 1991-2002 Linus Torvalds ++ * ++ * 1996-12-23 Modified by Dave Grothe to fix bugs in semaphores and ++ * make semaphores SMP safe ++ * 1998-11-19 Implemented schedule_timeout() and related stuff ++ * by Andrea Arcangeli ++ * 2002-01-04 New ultra-scalable O(1) scheduler by Ingo Molnar: ++ * hybrid priority-list and round-robin design with ++ * an array-switch method of distributing timeslices ++ * and per-CPU runqueues. Cleanups and useful suggestions ++ * by Davide Libenzi, preemptible kernel bits by Robert Love. ++ * 2003-09-03 Interactivity tuning by Con Kolivas. ++ * 2004-04-02 Scheduler domains code by Nick Piggin ++ * 2007-04-15 Work begun on replacing all interactivity tuning with a ++ * fair scheduling design by Con Kolivas. ++ * 2007-05-05 Load balancing (smp-nice) and other improvements ++ * by Peter Williams ++ * 2007-05-06 Interactivity improvements to CFS by Mike Galbraith ++ * 2007-07-01 Group scheduling enhancements by Srivatsa Vaddagiri ++ * 2007-11-29 RT balancing improvements by Steven Rostedt, Gregory Haskins, ++ * Thomas Gleixner, Mike Kravetz ++ * now Brainfuck deadline scheduling policy by Con Kolivas deletes ++ * a whole lot of those previous things. ++ */ ++ ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++ ++#include ++#include ++#include ++#include ++#ifdef CONFIG_PARAVIRT ++#include ++#endif ++ ++#include "cpupri.h" ++#include "../workqueue_internal.h" ++#include "../smpboot.h" ++ ++#define CREATE_TRACE_POINTS ++#include ++ ++#include "bfs_sched.h" ++ ++#define rt_prio(prio) unlikely((prio) < MAX_RT_PRIO) ++#define rt_task(p) rt_prio((p)->prio) ++#define rt_queue(rq) rt_prio((rq)->rq_prio) ++#define batch_task(p) (unlikely((p)->policy == SCHED_BATCH)) ++#define is_rt_policy(policy) ((policy) == SCHED_FIFO || \ ++ (policy) == SCHED_RR) ++#define has_rt_policy(p) unlikely(is_rt_policy((p)->policy)) ++#define idleprio_task(p) unlikely((p)->policy == SCHED_IDLEPRIO) ++#define iso_task(p) unlikely((p)->policy == SCHED_ISO) ++#define iso_queue(rq) unlikely((rq)->rq_policy == SCHED_ISO) ++#define rq_running_iso(rq) ((rq)->rq_prio == ISO_PRIO) ++ ++#define ISO_PERIOD ((5 * HZ * grq.noc) + 1) ++ ++/* ++ * Convert user-nice values [ -20 ... 0 ... 19 ] ++ * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ], ++ * and back. ++ */ ++#define NICE_TO_PRIO(nice) (MAX_RT_PRIO + (nice) + 20) ++#define PRIO_TO_NICE(prio) ((prio) - MAX_RT_PRIO - 20) ++#define TASK_NICE(p) PRIO_TO_NICE((p)->static_prio) ++ ++/* ++ * 'User priority' is the nice value converted to something we ++ * can work with better when scaling various scheduler parameters, ++ * it's a [ 0 ... 39 ] range. ++ */ ++#define USER_PRIO(p) ((p) - MAX_RT_PRIO) ++#define TASK_USER_PRIO(p) USER_PRIO((p)->static_prio) ++#define MAX_USER_PRIO (USER_PRIO(MAX_PRIO)) ++#define SCHED_PRIO(p) ((p) + MAX_RT_PRIO) ++#define STOP_PRIO (MAX_RT_PRIO - 1) ++ ++/* ++ * Some helpers for converting to/from various scales. Use shifts to get ++ * approximate multiples of ten for less overhead. ++ */ ++#define JIFFIES_TO_NS(TIME) ((TIME) * (1000000000 / HZ)) ++#define JIFFY_NS (1000000000 / HZ) ++#define HALF_JIFFY_NS (1000000000 / HZ / 2) ++#define HALF_JIFFY_US (1000000 / HZ / 2) ++#define MS_TO_NS(TIME) ((TIME) << 20) ++#define MS_TO_US(TIME) ((TIME) << 10) ++#define NS_TO_MS(TIME) ((TIME) >> 20) ++#define NS_TO_US(TIME) ((TIME) >> 10) ++ ++#define RESCHED_US (100) /* Reschedule if less than this many μs left */ ++ ++void print_scheduler_version(void) ++{ ++ printk(KERN_INFO "BFS CPU scheduler v0.444 by Con Kolivas.\n"); ++} ++ ++/* ++ * This is the time all tasks within the same priority round robin. ++ * Value is in ms and set to a minimum of 6ms. Scales with number of cpus. ++ * Tunable via /proc interface. ++ */ ++int rr_interval __read_mostly = 6; ++ ++/* ++ * sched_iso_cpu - sysctl which determines the cpu percentage SCHED_ISO tasks ++ * are allowed to run five seconds as real time tasks. This is the total over ++ * all online cpus. ++ */ ++int sched_iso_cpu __read_mostly = 70; ++ ++/* ++ * The relative length of deadline for each priority(nice) level. ++ */ ++static int prio_ratios[PRIO_RANGE] __read_mostly; ++ ++/* ++ * The quota handed out to tasks of all priority levels when refilling their ++ * time_slice. ++ */ ++static inline int timeslice(void) ++{ ++ return MS_TO_US(rr_interval); ++} ++ ++/* ++ * The global runqueue data that all CPUs work off. Data is protected either ++ * by the global grq lock, or the discrete lock that precedes the data in this ++ * struct. ++ */ ++struct global_rq { ++ raw_spinlock_t lock; ++ unsigned long nr_running; ++ unsigned long nr_uninterruptible; ++ unsigned long long nr_switches; ++ struct list_head queue[PRIO_LIMIT]; ++ DECLARE_BITMAP(prio_bitmap, PRIO_LIMIT + 1); ++#ifdef CONFIG_SMP ++ unsigned long qnr; /* queued not running */ ++ cpumask_t cpu_idle_map; ++ bool idle_cpus; ++#endif ++ int noc; /* num_online_cpus stored and updated when it changes */ ++ u64 niffies; /* Nanosecond jiffies */ ++ unsigned long last_jiffy; /* Last jiffy we updated niffies */ ++ ++ raw_spinlock_t iso_lock; ++ int iso_ticks; ++ bool iso_refractory; ++}; ++ ++#ifdef CONFIG_SMP ++ ++/* ++ * We add the notion of a root-domain which will be used to define per-domain ++ * variables. Each exclusive cpuset essentially defines an island domain by ++ * fully partitioning the member cpus from any other cpuset. Whenever a new ++ * exclusive cpuset is created, we also create and attach a new root-domain ++ * object. ++ * ++ */ ++struct root_domain { ++ atomic_t refcount; ++ atomic_t rto_count; ++ struct rcu_head rcu; ++ cpumask_var_t span; ++ cpumask_var_t online; ++ ++ /* ++ * The "RT overload" flag: it gets set if a CPU has more than ++ * one runnable RT task. ++ */ ++ cpumask_var_t rto_mask; ++ struct cpupri cpupri; ++}; ++ ++/* ++ * By default the system creates a single root-domain with all cpus as ++ * members (mimicking the global state we have today). ++ */ ++static struct root_domain def_root_domain; ++ ++#endif /* CONFIG_SMP */ ++ ++/* There can be only one */ ++static struct global_rq grq; ++ ++DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues); ++static DEFINE_MUTEX(sched_hotcpu_mutex); ++ ++#ifdef CONFIG_SMP ++struct rq *cpu_rq(int cpu) ++{ ++ return &per_cpu(runqueues, (cpu)); ++} ++#define this_rq() (&__get_cpu_var(runqueues)) ++#define task_rq(p) cpu_rq(task_cpu(p)) ++#define cpu_curr(cpu) (cpu_rq(cpu)->curr) ++/* ++ * sched_domains_mutex serialises calls to init_sched_domains, ++ * detach_destroy_domains and partition_sched_domains. ++ */ ++static DEFINE_MUTEX(sched_domains_mutex); ++ ++/* ++ * By default the system creates a single root-domain with all cpus as ++ * members (mimicking the global state we have today). ++ */ ++static struct root_domain def_root_domain; ++ ++int __weak arch_sd_sibling_asym_packing(void) ++{ ++ return 0*SD_ASYM_PACKING; ++} ++#endif /* CONFIG_SMP */ ++ ++static inline void update_rq_clock(struct rq *rq); ++static unsigned long long do_task_sched_runtime(struct task_struct *p); ++static u64 do_task_delta_exec(struct task_struct *p, struct rq *rq); ++ ++/* ++ * Sanity check should sched_clock return bogus values. We make sure it does ++ * not appear to go backwards, and use jiffies to determine the maximum and ++ * minimum it could possibly have increased, and round down to the nearest ++ * jiffy when it falls outside this. ++ */ ++static inline void niffy_diff(s64 *niff_diff, int jiff_diff) ++{ ++ unsigned long min_diff, max_diff; ++ ++ if (jiff_diff > 1) ++ min_diff = JIFFIES_TO_NS(jiff_diff - 1); ++ else ++ min_diff = 1; ++ /* Round up to the nearest tick for maximum */ ++ max_diff = JIFFIES_TO_NS(jiff_diff + 1); ++ ++ if (unlikely(*niff_diff < min_diff || *niff_diff > max_diff)) ++ *niff_diff = min_diff; ++} ++ ++#ifdef CONFIG_SMP ++static inline int cpu_of(struct rq *rq) ++{ ++ return rq->cpu; ++} ++ ++/* ++ * Niffies are a globally increasing nanosecond counter. Whenever a runqueue ++ * clock is updated with the grq.lock held, it is an opportunity to update the ++ * niffies value. Any CPU can update it by adding how much its clock has ++ * increased since it last updated niffies, minus any added niffies by other ++ * CPUs. ++ */ ++static inline void update_clocks(struct rq *rq) ++{ ++ s64 ndiff; ++ long jdiff; ++ ++ update_rq_clock(rq); ++ ndiff = rq->clock - rq->old_clock; ++ /* old_clock is only updated when we are updating niffies */ ++ rq->old_clock = rq->clock; ++ ndiff -= grq.niffies - rq->last_niffy; ++ jdiff = jiffies - grq.last_jiffy; ++ niffy_diff(&ndiff, jdiff); ++ grq.last_jiffy += jdiff; ++ grq.niffies += ndiff; ++ rq->last_niffy = grq.niffies; ++} ++#else /* CONFIG_SMP */ ++static struct rq *uprq; ++#define cpu_rq(cpu) (uprq) ++#define this_rq() (uprq) ++#define task_rq(p) (uprq) ++#define cpu_curr(cpu) ((uprq)->curr) ++static inline int cpu_of(struct rq *rq) ++{ ++ return 0; ++} ++ ++static inline void update_clocks(struct rq *rq) ++{ ++ s64 ndiff; ++ long jdiff; ++ ++ update_rq_clock(rq); ++ ndiff = rq->clock - rq->old_clock; ++ rq->old_clock = rq->clock; ++ jdiff = jiffies - grq.last_jiffy; ++ niffy_diff(&ndiff, jdiff); ++ grq.last_jiffy += jdiff; ++ grq.niffies += ndiff; ++} ++#endif ++#define raw_rq() (&__raw_get_cpu_var(runqueues)) ++ ++#include "stats.h" ++ ++#ifndef prepare_arch_switch ++# define prepare_arch_switch(next) do { } while (0) ++#endif ++#ifndef finish_arch_switch ++# define finish_arch_switch(prev) do { } while (0) ++#endif ++#ifndef finish_arch_post_lock_switch ++# define finish_arch_post_lock_switch() do { } while (0) ++#endif ++ ++/* ++ * All common locking functions performed on grq.lock. rq->clock is local to ++ * the CPU accessing it so it can be modified just with interrupts disabled ++ * when we're not updating niffies. ++ * Looking up task_rq must be done under grq.lock to be safe. ++ */ ++static void update_rq_clock_task(struct rq *rq, s64 delta); ++ ++static inline void update_rq_clock(struct rq *rq) ++{ ++ s64 delta = sched_clock_cpu(cpu_of(rq)) - rq->clock; ++ ++ rq->clock += delta; ++ update_rq_clock_task(rq, delta); ++} ++ ++static inline bool task_running(struct task_struct *p) ++{ ++ return p->on_cpu; ++} ++ ++static inline void grq_lock(void) ++ __acquires(grq.lock) ++{ ++ raw_spin_lock(&grq.lock); ++} ++ ++static inline void grq_unlock(void) ++ __releases(grq.lock) ++{ ++ raw_spin_unlock(&grq.lock); ++} ++ ++static inline void grq_lock_irq(void) ++ __acquires(grq.lock) ++{ ++ raw_spin_lock_irq(&grq.lock); ++} ++ ++static inline void time_lock_grq(struct rq *rq) ++ __acquires(grq.lock) ++{ ++ grq_lock(); ++ update_clocks(rq); ++} ++ ++static inline void grq_unlock_irq(void) ++ __releases(grq.lock) ++{ ++ raw_spin_unlock_irq(&grq.lock); ++} ++ ++static inline void grq_lock_irqsave(unsigned long *flags) ++ __acquires(grq.lock) ++{ ++ raw_spin_lock_irqsave(&grq.lock, *flags); ++} ++ ++static inline void grq_unlock_irqrestore(unsigned long *flags) ++ __releases(grq.lock) ++{ ++ raw_spin_unlock_irqrestore(&grq.lock, *flags); ++} ++ ++static inline struct rq ++*task_grq_lock(struct task_struct *p, unsigned long *flags) ++ __acquires(grq.lock) ++{ ++ grq_lock_irqsave(flags); ++ return task_rq(p); ++} ++ ++static inline struct rq ++*time_task_grq_lock(struct task_struct *p, unsigned long *flags) ++ __acquires(grq.lock) ++{ ++ struct rq *rq = task_grq_lock(p, flags); ++ update_clocks(rq); ++ return rq; ++} ++ ++static inline struct rq *task_grq_lock_irq(struct task_struct *p) ++ __acquires(grq.lock) ++{ ++ grq_lock_irq(); ++ return task_rq(p); ++} ++ ++static inline void time_task_grq_lock_irq(struct task_struct *p) ++ __acquires(grq.lock) ++{ ++ struct rq *rq = task_grq_lock_irq(p); ++ update_clocks(rq); ++} ++ ++static inline void task_grq_unlock_irq(void) ++ __releases(grq.lock) ++{ ++ grq_unlock_irq(); ++} ++ ++static inline void task_grq_unlock(unsigned long *flags) ++ __releases(grq.lock) ++{ ++ grq_unlock_irqrestore(flags); ++} ++ ++/** ++ * grunqueue_is_locked ++ * ++ * Returns true if the global runqueue is locked. ++ * This interface allows printk to be called with the runqueue lock ++ * held and know whether or not it is OK to wake up the klogd. ++ */ ++bool grunqueue_is_locked(void) ++{ ++ return raw_spin_is_locked(&grq.lock); ++} ++ ++void grq_unlock_wait(void) ++ __releases(grq.lock) ++{ ++ smp_mb(); /* spin-unlock-wait is not a full memory barrier */ ++ raw_spin_unlock_wait(&grq.lock); ++} ++ ++static inline void time_grq_lock(struct rq *rq, unsigned long *flags) ++ __acquires(grq.lock) ++{ ++ local_irq_save(*flags); ++ time_lock_grq(rq); ++} ++ ++static inline struct rq *__task_grq_lock(struct task_struct *p) ++ __acquires(grq.lock) ++{ ++ grq_lock(); ++ return task_rq(p); ++} ++ ++static inline void __task_grq_unlock(void) ++ __releases(grq.lock) ++{ ++ grq_unlock(); ++} ++ ++/* ++ * Look for any tasks *anywhere* that are running nice 0 or better. We do ++ * this lockless for overhead reasons since the occasional wrong result ++ * is harmless. ++ */ ++bool above_background_load(void) ++{ ++ int cpu; ++ ++ for_each_online_cpu(cpu) { ++ struct task_struct *cpu_curr = cpu_rq(cpu)->curr; ++ ++ if (unlikely(!cpu_curr)) ++ continue; ++ if (PRIO_TO_NICE(cpu_curr->static_prio) < 1) { ++ return true; ++ } ++ } ++ return false; ++} ++ ++#ifndef __ARCH_WANT_UNLOCKED_CTXSW ++static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next) ++{ ++} ++ ++static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev) ++{ ++#ifdef CONFIG_DEBUG_SPINLOCK ++ /* this is a valid case when another task releases the spinlock */ ++ grq.lock.owner = current; ++#endif ++ /* ++ * If we are tracking spinlock dependencies then we have to ++ * fix up the runqueue lock - which gets 'carried over' from ++ * prev into current: ++ */ ++ spin_acquire(&grq.lock.dep_map, 0, 0, _THIS_IP_); ++ ++ grq_unlock_irq(); ++} ++ ++#else /* __ARCH_WANT_UNLOCKED_CTXSW */ ++ ++static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next) ++{ ++#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW ++ grq_unlock_irq(); ++#else ++ grq_unlock(); ++#endif ++} ++ ++static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev) ++{ ++ smp_wmb(); ++#ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW ++ local_irq_enable(); ++#endif ++} ++#endif /* __ARCH_WANT_UNLOCKED_CTXSW */ ++ ++static inline bool deadline_before(u64 deadline, u64 time) ++{ ++ return (deadline < time); ++} ++ ++static inline bool deadline_after(u64 deadline, u64 time) ++{ ++ return (deadline > time); ++} ++ ++/* ++ * A task that is queued but not running will be on the grq run list. ++ * A task that is not running or queued will not be on the grq run list. ++ * A task that is currently running will have ->on_cpu set but not on the ++ * grq run list. ++ */ ++static inline bool task_queued(struct task_struct *p) ++{ ++ return (!list_empty(&p->run_list)); ++} ++ ++/* ++ * Removing from the global runqueue. Enter with grq locked. ++ */ ++static void dequeue_task(struct task_struct *p) ++{ ++ list_del_init(&p->run_list); ++ if (list_empty(grq.queue + p->prio)) ++ __clear_bit(p->prio, grq.prio_bitmap); ++} ++ ++/* ++ * To determine if it's safe for a task of SCHED_IDLEPRIO to actually run as ++ * an idle task, we ensure none of the following conditions are met. ++ */ ++static bool idleprio_suitable(struct task_struct *p) ++{ ++ return (!freezing(p) && !signal_pending(p) && ++ !(task_contributes_to_load(p)) && !(p->flags & (PF_EXITING))); ++} ++ ++/* ++ * To determine if a task of SCHED_ISO can run in pseudo-realtime, we check ++ * that the iso_refractory flag is not set. ++ */ ++static bool isoprio_suitable(void) ++{ ++ return !grq.iso_refractory; ++} ++ ++/* ++ * Adding to the global runqueue. Enter with grq locked. ++ */ ++static void enqueue_task(struct task_struct *p) ++{ ++ if (!rt_task(p)) { ++ /* Check it hasn't gotten rt from PI */ ++ if ((idleprio_task(p) && idleprio_suitable(p)) || ++ (iso_task(p) && isoprio_suitable())) ++ p->prio = p->normal_prio; ++ else ++ p->prio = NORMAL_PRIO; ++ } ++ __set_bit(p->prio, grq.prio_bitmap); ++ list_add_tail(&p->run_list, grq.queue + p->prio); ++ sched_info_queued(p); ++} ++ ++/* Only idle task does this as a real time task*/ ++static inline void enqueue_task_head(struct task_struct *p) ++{ ++ __set_bit(p->prio, grq.prio_bitmap); ++ list_add(&p->run_list, grq.queue + p->prio); ++ sched_info_queued(p); ++} ++ ++static inline void requeue_task(struct task_struct *p) ++{ ++ sched_info_queued(p); ++} ++ ++/* ++ * Returns the relative length of deadline all compared to the shortest ++ * deadline which is that of nice -20. ++ */ ++static inline int task_prio_ratio(struct task_struct *p) ++{ ++ return prio_ratios[TASK_USER_PRIO(p)]; ++} ++ ++/* ++ * task_timeslice - all tasks of all priorities get the exact same timeslice ++ * length. CPU distribution is handled by giving different deadlines to ++ * tasks of different priorities. Use 128 as the base value for fast shifts. ++ */ ++static inline int task_timeslice(struct task_struct *p) ++{ ++ return (rr_interval * task_prio_ratio(p) / 128); ++} ++ ++#ifdef CONFIG_SMP ++/* ++ * qnr is the "queued but not running" count which is the total number of ++ * tasks on the global runqueue list waiting for cpu time but not actually ++ * currently running on a cpu. ++ */ ++static inline void inc_qnr(void) ++{ ++ grq.qnr++; ++} ++ ++static inline void dec_qnr(void) ++{ ++ grq.qnr--; ++} ++ ++static inline int queued_notrunning(void) ++{ ++ return grq.qnr; ++} ++ ++/* ++ * The cpu_idle_map stores a bitmap of all the CPUs currently idle to ++ * allow easy lookup of whether any suitable idle CPUs are available. ++ * It's cheaper to maintain a binary yes/no if there are any idle CPUs on the ++ * idle_cpus variable than to do a full bitmask check when we are busy. ++ */ ++static inline void set_cpuidle_map(int cpu) ++{ ++ if (likely(cpu_online(cpu))) { ++ cpu_set(cpu, grq.cpu_idle_map); ++ grq.idle_cpus = true; ++ } ++} ++ ++static inline void clear_cpuidle_map(int cpu) ++{ ++ cpu_clear(cpu, grq.cpu_idle_map); ++ if (cpus_empty(grq.cpu_idle_map)) ++ grq.idle_cpus = false; ++} ++ ++static bool suitable_idle_cpus(struct task_struct *p) ++{ ++ if (!grq.idle_cpus) ++ return false; ++ return (cpus_intersects(p->cpus_allowed, grq.cpu_idle_map)); ++} ++ ++#define CPUIDLE_DIFF_THREAD (1) ++#define CPUIDLE_DIFF_CORE (2) ++#define CPUIDLE_CACHE_BUSY (4) ++#define CPUIDLE_DIFF_CPU (8) ++#define CPUIDLE_THREAD_BUSY (16) ++#define CPUIDLE_THROTTLED (32) ++#define CPUIDLE_DIFF_NODE (64) ++ ++static void resched_task(struct task_struct *p); ++static inline bool scaling_rq(struct rq *rq); ++ ++/* ++ * The best idle CPU is chosen according to the CPUIDLE ranking above where the ++ * lowest value would give the most suitable CPU to schedule p onto next. The ++ * order works out to be the following: ++ * ++ * Same core, idle or busy cache, idle or busy threads ++ * Other core, same cache, idle or busy cache, idle threads. ++ * Same node, other CPU, idle cache, idle threads. ++ * Same node, other CPU, busy cache, idle threads. ++ * Other core, same cache, busy threads. ++ * Same node, other CPU, busy threads. ++ * Other node, other CPU, idle cache, idle threads. ++ * Other node, other CPU, busy cache, idle threads. ++ * Other node, other CPU, busy threads. ++ */ ++static void ++resched_best_mask(int best_cpu, struct rq *rq, cpumask_t *tmpmask) ++{ ++ int best_ranking = CPUIDLE_DIFF_NODE | CPUIDLE_THROTTLED | ++ CPUIDLE_THREAD_BUSY | CPUIDLE_DIFF_CPU | CPUIDLE_CACHE_BUSY | ++ CPUIDLE_DIFF_CORE | CPUIDLE_DIFF_THREAD; ++ int cpu_tmp; ++ ++ if (cpu_isset(best_cpu, *tmpmask)) ++ goto out; ++ ++ for_each_cpu_mask(cpu_tmp, *tmpmask) { ++ int ranking, locality; ++ struct rq *tmp_rq; ++ ++ ranking = 0; ++ tmp_rq = cpu_rq(cpu_tmp); ++ ++ locality = rq->cpu_locality[cpu_tmp]; ++#ifdef CONFIG_NUMA ++ if (locality > 3) ++ ranking |= CPUIDLE_DIFF_NODE; ++ else ++#endif ++ if (locality > 2) ++ ranking |= CPUIDLE_DIFF_CPU; ++#ifdef CONFIG_SCHED_MC ++ else if (locality == 2) ++ ranking |= CPUIDLE_DIFF_CORE; ++ if (!(tmp_rq->cache_idle(cpu_tmp))) ++ ranking |= CPUIDLE_CACHE_BUSY; ++#endif ++#ifdef CONFIG_SCHED_SMT ++ if (locality == 1) ++ ranking |= CPUIDLE_DIFF_THREAD; ++ if (!(tmp_rq->siblings_idle(cpu_tmp))) ++ ranking |= CPUIDLE_THREAD_BUSY; ++#endif ++ if (scaling_rq(tmp_rq)) ++ ranking |= CPUIDLE_THROTTLED; ++ ++ if (ranking < best_ranking) { ++ best_cpu = cpu_tmp; ++ best_ranking = ranking; ++ } ++ } ++out: ++ resched_task(cpu_rq(best_cpu)->curr); ++} ++ ++bool cpus_share_cache(int this_cpu, int that_cpu) ++{ ++ struct rq *this_rq = cpu_rq(this_cpu); ++ ++ return (this_rq->cpu_locality[that_cpu] < 3); ++} ++ ++static void resched_best_idle(struct task_struct *p) ++{ ++ cpumask_t tmpmask; ++ ++ cpus_and(tmpmask, p->cpus_allowed, grq.cpu_idle_map); ++ resched_best_mask(task_cpu(p), task_rq(p), &tmpmask); ++} ++ ++static inline void resched_suitable_idle(struct task_struct *p) ++{ ++ if (suitable_idle_cpus(p)) ++ resched_best_idle(p); ++} ++/* ++ * Flags to tell us whether this CPU is running a CPU frequency governor that ++ * has slowed its speed or not. No locking required as the very rare wrongly ++ * read value would be harmless. ++ */ ++void cpu_scaling(int cpu) ++{ ++ cpu_rq(cpu)->scaling = true; ++} ++ ++void cpu_nonscaling(int cpu) ++{ ++ cpu_rq(cpu)->scaling = false; ++} ++ ++static inline bool scaling_rq(struct rq *rq) ++{ ++ return rq->scaling; ++} ++ ++static inline int locality_diff(struct task_struct *p, struct rq *rq) ++{ ++ return rq->cpu_locality[task_cpu(p)]; ++} ++#else /* CONFIG_SMP */ ++static inline void inc_qnr(void) ++{ ++} ++ ++static inline void dec_qnr(void) ++{ ++} ++ ++static inline int queued_notrunning(void) ++{ ++ return grq.nr_running; ++} ++ ++static inline void set_cpuidle_map(int cpu) ++{ ++} ++ ++static inline void clear_cpuidle_map(int cpu) ++{ ++} ++ ++static inline bool suitable_idle_cpus(struct task_struct *p) ++{ ++ return uprq->curr == uprq->idle; ++} ++ ++static inline void resched_suitable_idle(struct task_struct *p) ++{ ++} ++ ++void cpu_scaling(int __unused) ++{ ++} ++ ++void cpu_nonscaling(int __unused) ++{ ++} ++ ++/* ++ * Although CPUs can scale in UP, there is nowhere else for tasks to go so this ++ * always returns 0. ++ */ ++static inline bool scaling_rq(struct rq *rq) ++{ ++ return false; ++} ++ ++static inline int locality_diff(struct task_struct *p, struct rq *rq) ++{ ++ return 0; ++} ++#endif /* CONFIG_SMP */ ++EXPORT_SYMBOL_GPL(cpu_scaling); ++EXPORT_SYMBOL_GPL(cpu_nonscaling); ++ ++/* ++ * activate_idle_task - move idle task to the _front_ of runqueue. ++ */ ++static inline void activate_idle_task(struct task_struct *p) ++{ ++ enqueue_task_head(p); ++ grq.nr_running++; ++ inc_qnr(); ++} ++ ++static inline int normal_prio(struct task_struct *p) ++{ ++ if (has_rt_policy(p)) ++ return MAX_RT_PRIO - 1 - p->rt_priority; ++ if (idleprio_task(p)) ++ return IDLE_PRIO; ++ if (iso_task(p)) ++ return ISO_PRIO; ++ return NORMAL_PRIO; ++} ++ ++/* ++ * Calculate the current priority, i.e. the priority ++ * taken into account by the scheduler. This value might ++ * be boosted by RT tasks as it will be RT if the task got ++ * RT-boosted. If not then it returns p->normal_prio. ++ */ ++static int effective_prio(struct task_struct *p) ++{ ++ p->normal_prio = normal_prio(p); ++ /* ++ * If we are RT tasks or we were boosted to RT priority, ++ * keep the priority unchanged. Otherwise, update priority ++ * to the normal priority: ++ */ ++ if (!rt_prio(p->prio)) ++ return p->normal_prio; ++ return p->prio; ++} ++ ++/* ++ * activate_task - move a task to the runqueue. Enter with grq locked. ++ */ ++static void activate_task(struct task_struct *p, struct rq *rq) ++{ ++ update_clocks(rq); ++ ++ /* ++ * Sleep time is in units of nanosecs, so shift by 20 to get a ++ * milliseconds-range estimation of the amount of time that the task ++ * spent sleeping: ++ */ ++ if (unlikely(prof_on == SLEEP_PROFILING)) { ++ if (p->state == TASK_UNINTERRUPTIBLE) ++ profile_hits(SLEEP_PROFILING, (void *)get_wchan(p), ++ (rq->clock_task - p->last_ran) >> 20); ++ } ++ ++ p->prio = effective_prio(p); ++ if (task_contributes_to_load(p)) ++ grq.nr_uninterruptible--; ++ enqueue_task(p); ++ grq.nr_running++; ++ inc_qnr(); ++} ++ ++static inline void clear_sticky(struct task_struct *p); ++ ++/* ++ * deactivate_task - If it's running, it's not on the grq and we can just ++ * decrement the nr_running. Enter with grq locked. ++ */ ++static inline void deactivate_task(struct task_struct *p) ++{ ++ if (task_contributes_to_load(p)) ++ grq.nr_uninterruptible++; ++ grq.nr_running--; ++ clear_sticky(p); ++} ++ ++#ifdef CONFIG_SMP ++void set_task_cpu(struct task_struct *p, unsigned int cpu) ++{ ++#ifdef CONFIG_LOCKDEP ++ /* ++ * The caller should hold grq lock. ++ */ ++ WARN_ON_ONCE(debug_locks && !lockdep_is_held(&grq.lock)); ++#endif ++ trace_sched_migrate_task(p, cpu); ++ if (task_cpu(p) != cpu) ++ perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS, 1, NULL, 0); ++ ++ /* ++ * After ->cpu is set up to a new value, task_grq_lock(p, ...) can be ++ * successfully executed on another CPU. We must ensure that updates of ++ * per-task data have been completed by this moment. ++ */ ++ smp_wmb(); ++ task_thread_info(p)->cpu = cpu; ++} ++ ++static inline void clear_sticky(struct task_struct *p) ++{ ++ p->sticky = false; ++} ++ ++static inline bool task_sticky(struct task_struct *p) ++{ ++ return p->sticky; ++} ++ ++/* Reschedule the best idle CPU that is not this one. */ ++static void ++resched_closest_idle(struct rq *rq, int cpu, struct task_struct *p) ++{ ++ cpumask_t tmpmask; ++ ++ cpus_and(tmpmask, p->cpus_allowed, grq.cpu_idle_map); ++ cpu_clear(cpu, tmpmask); ++ if (cpus_empty(tmpmask)) ++ return; ++ resched_best_mask(cpu, rq, &tmpmask); ++} ++ ++/* ++ * We set the sticky flag on a task that is descheduled involuntarily meaning ++ * it is awaiting further CPU time. If the last sticky task is still sticky ++ * but unlucky enough to not be the next task scheduled, we unstick it and try ++ * to find it an idle CPU. Realtime tasks do not stick to minimise their ++ * latency at all times. ++ */ ++static inline void ++swap_sticky(struct rq *rq, int cpu, struct task_struct *p) ++{ ++ if (rq->sticky_task) { ++ if (rq->sticky_task == p) { ++ p->sticky = true; ++ return; ++ } ++ if (task_sticky(rq->sticky_task)) { ++ clear_sticky(rq->sticky_task); ++ resched_closest_idle(rq, cpu, rq->sticky_task); ++ } ++ } ++ if (!rt_task(p)) { ++ p->sticky = true; ++ rq->sticky_task = p; ++ } else { ++ resched_closest_idle(rq, cpu, p); ++ rq->sticky_task = NULL; ++ } ++} ++ ++static inline void unstick_task(struct rq *rq, struct task_struct *p) ++{ ++ rq->sticky_task = NULL; ++ clear_sticky(p); ++} ++#else ++static inline void clear_sticky(struct task_struct *p) ++{ ++} ++ ++static inline bool task_sticky(struct task_struct *p) ++{ ++ return false; ++} ++ ++static inline void ++swap_sticky(struct rq *rq, int cpu, struct task_struct *p) ++{ ++} ++ ++static inline void unstick_task(struct rq *rq, struct task_struct *p) ++{ ++} ++#endif ++ ++/* ++ * Move a task off the global queue and take it to a cpu for it will ++ * become the running task. ++ */ ++static inline void take_task(int cpu, struct task_struct *p) ++{ ++ set_task_cpu(p, cpu); ++ dequeue_task(p); ++ clear_sticky(p); ++ dec_qnr(); ++} ++ ++/* ++ * Returns a descheduling task to the grq runqueue unless it is being ++ * deactivated. ++ */ ++static inline void return_task(struct task_struct *p, bool deactivate) ++{ ++ if (deactivate) ++ deactivate_task(p); ++ else { ++ inc_qnr(); ++ enqueue_task(p); ++ } ++} ++ ++/* ++ * resched_task - mark a task 'to be rescheduled now'. ++ * ++ * On UP this means the setting of the need_resched flag, on SMP it ++ * might also involve a cross-CPU call to trigger the scheduler on ++ * the target CPU. ++ */ ++#ifdef CONFIG_SMP ++ ++#ifndef tsk_is_polling ++#define tsk_is_polling(t) 0 ++#endif ++ ++static void resched_task(struct task_struct *p) ++{ ++ int cpu; ++ ++ assert_raw_spin_locked(&grq.lock); ++ ++ if (unlikely(test_tsk_thread_flag(p, TIF_NEED_RESCHED))) ++ return; ++ ++ set_tsk_thread_flag(p, TIF_NEED_RESCHED); ++ ++ cpu = task_cpu(p); ++ if (cpu == smp_processor_id()) ++ return; ++ ++ /* NEED_RESCHED must be visible before we test polling */ ++ smp_mb(); ++ if (!tsk_is_polling(p)) ++ smp_send_reschedule(cpu); ++} ++ ++#else ++static inline void resched_task(struct task_struct *p) ++{ ++ assert_raw_spin_locked(&grq.lock); ++ set_tsk_need_resched(p); ++} ++#endif ++ ++/** ++ * task_curr - is this task currently executing on a CPU? ++ * @p: the task in question. ++ * ++ * Return: 1 if the task is currently executing. 0 otherwise. ++ */ ++inline int task_curr(const struct task_struct *p) ++{ ++ return cpu_curr(task_cpu(p)) == p; ++} ++ ++#ifdef CONFIG_SMP ++struct migration_req { ++ struct task_struct *task; ++ int dest_cpu; ++}; ++ ++/* ++ * wait_task_inactive - wait for a thread to unschedule. ++ * ++ * If @match_state is nonzero, it's the @p->state value just checked and ++ * not expected to change. If it changes, i.e. @p might have woken up, ++ * then return zero. When we succeed in waiting for @p to be off its CPU, ++ * we return a positive number (its total switch count). If a second call ++ * a short while later returns the same number, the caller can be sure that ++ * @p has remained unscheduled the whole time. ++ * ++ * The caller must ensure that the task *will* unschedule sometime soon, ++ * else this function might spin for a *long* time. This function can't ++ * be called with interrupts off, or it may introduce deadlock with ++ * smp_call_function() if an IPI is sent by the same process we are ++ * waiting to become inactive. ++ */ ++unsigned long wait_task_inactive(struct task_struct *p, long match_state) ++{ ++ unsigned long flags; ++ bool running, on_rq; ++ unsigned long ncsw; ++ struct rq *rq; ++ ++ for (;;) { ++ /* ++ * We do the initial early heuristics without holding ++ * any task-queue locks at all. We'll only try to get ++ * the runqueue lock when things look like they will ++ * work out! In the unlikely event rq is dereferenced ++ * since we're lockless, grab it again. ++ */ ++#ifdef CONFIG_SMP ++retry_rq: ++ rq = task_rq(p); ++ if (unlikely(!rq)) ++ goto retry_rq; ++#else /* CONFIG_SMP */ ++ rq = task_rq(p); ++#endif ++ /* ++ * If the task is actively running on another CPU ++ * still, just relax and busy-wait without holding ++ * any locks. ++ * ++ * NOTE! Since we don't hold any locks, it's not ++ * even sure that "rq" stays as the right runqueue! ++ * But we don't care, since this will return false ++ * if the runqueue has changed and p is actually now ++ * running somewhere else! ++ */ ++ while (task_running(p) && p == rq->curr) { ++ if (match_state && unlikely(p->state != match_state)) ++ return 0; ++ cpu_relax(); ++ } ++ ++ /* ++ * Ok, time to look more closely! We need the grq ++ * lock now, to be *sure*. If we're wrong, we'll ++ * just go back and repeat. ++ */ ++ rq = task_grq_lock(p, &flags); ++ trace_sched_wait_task(p); ++ running = task_running(p); ++ on_rq = task_queued(p); ++ ncsw = 0; ++ if (!match_state || p->state == match_state) ++ ncsw = p->nvcsw | LONG_MIN; /* sets MSB */ ++ task_grq_unlock(&flags); ++ ++ /* ++ * If it changed from the expected state, bail out now. ++ */ ++ if (unlikely(!ncsw)) ++ break; ++ ++ /* ++ * Was it really running after all now that we ++ * checked with the proper locks actually held? ++ * ++ * Oops. Go back and try again.. ++ */ ++ if (unlikely(running)) { ++ cpu_relax(); ++ continue; ++ } ++ ++ /* ++ * It's not enough that it's not actively running, ++ * it must be off the runqueue _entirely_, and not ++ * preempted! ++ * ++ * So if it was still runnable (but just not actively ++ * running right now), it's preempted, and we should ++ * yield - it could be a while. ++ */ ++ if (unlikely(on_rq)) { ++ ktime_t to = ktime_set(0, NSEC_PER_SEC / HZ); ++ ++ set_current_state(TASK_UNINTERRUPTIBLE); ++ schedule_hrtimeout(&to, HRTIMER_MODE_REL); ++ continue; ++ } ++ ++ /* ++ * Ahh, all good. It wasn't running, and it wasn't ++ * runnable, which means that it will never become ++ * running in the future either. We're all done! ++ */ ++ break; ++ } ++ ++ return ncsw; ++} ++ ++/*** ++ * kick_process - kick a running thread to enter/exit the kernel ++ * @p: the to-be-kicked thread ++ * ++ * Cause a process which is running on another CPU to enter ++ * kernel-mode, without any delay. (to get signals handled.) ++ * ++ * NOTE: this function doesn't have to take the runqueue lock, ++ * because all it wants to ensure is that the remote task enters ++ * the kernel. If the IPI races and the task has been migrated ++ * to another CPU then no harm is done and the purpose has been ++ * achieved as well. ++ */ ++void kick_process(struct task_struct *p) ++{ ++ int cpu; ++ ++ preempt_disable(); ++ cpu = task_cpu(p); ++ if ((cpu != smp_processor_id()) && task_curr(p)) ++ smp_send_reschedule(cpu); ++ preempt_enable(); ++} ++EXPORT_SYMBOL_GPL(kick_process); ++#endif ++ ++#define rq_idle(rq) ((rq)->rq_prio == PRIO_LIMIT) ++ ++/* ++ * RT tasks preempt purely on priority. SCHED_NORMAL tasks preempt on the ++ * basis of earlier deadlines. SCHED_IDLEPRIO don't preempt anything else or ++ * between themselves, they cooperatively multitask. An idle rq scores as ++ * prio PRIO_LIMIT so it is always preempted. ++ */ ++static inline bool ++can_preempt(struct task_struct *p, int prio, u64 deadline) ++{ ++ /* Better static priority RT task or better policy preemption */ ++ if (p->prio < prio) ++ return true; ++ if (p->prio > prio) ++ return false; ++ /* SCHED_NORMAL, BATCH and ISO will preempt based on deadline */ ++ if (!deadline_before(p->deadline, deadline)) ++ return false; ++ return true; ++} ++ ++#ifdef CONFIG_SMP ++#define cpu_online_map (*(cpumask_t *)cpu_online_mask) ++#ifdef CONFIG_HOTPLUG_CPU ++/* ++ * Check to see if there is a task that is affined only to offline CPUs but ++ * still wants runtime. This happens to kernel threads during suspend/halt and ++ * disabling of CPUs. ++ */ ++static inline bool online_cpus(struct task_struct *p) ++{ ++ return (likely(cpus_intersects(cpu_online_map, p->cpus_allowed))); ++} ++#else /* CONFIG_HOTPLUG_CPU */ ++/* All available CPUs are always online without hotplug. */ ++static inline bool online_cpus(struct task_struct *p) ++{ ++ return true; ++} ++#endif ++ ++/* ++ * Check to see if p can run on cpu, and if not, whether there are any online ++ * CPUs it can run on instead. ++ */ ++static inline bool needs_other_cpu(struct task_struct *p, int cpu) ++{ ++ if (unlikely(!cpu_isset(cpu, p->cpus_allowed))) ++ return true; ++ return false; ++} ++ ++/* ++ * When all else is equal, still prefer this_rq. ++ */ ++static void try_preempt(struct task_struct *p, struct rq *this_rq) ++{ ++ struct rq *highest_prio_rq = NULL; ++ int cpu, highest_prio; ++ u64 latest_deadline; ++ cpumask_t tmp; ++ ++ /* ++ * We clear the sticky flag here because for a task to have called ++ * try_preempt with the sticky flag enabled means some complicated ++ * re-scheduling has occurred and we should ignore the sticky flag. ++ */ ++ clear_sticky(p); ++ ++ if (suitable_idle_cpus(p)) { ++ resched_best_idle(p); ++ return; ++ } ++ ++ /* IDLEPRIO tasks never preempt anything but idle */ ++ if (p->policy == SCHED_IDLEPRIO) ++ return; ++ ++ if (likely(online_cpus(p))) ++ cpus_and(tmp, cpu_online_map, p->cpus_allowed); ++ else ++ return; ++ ++ highest_prio = latest_deadline = 0; ++ ++ for_each_cpu_mask(cpu, tmp) { ++ struct rq *rq; ++ int rq_prio; ++ ++ rq = cpu_rq(cpu); ++ rq_prio = rq->rq_prio; ++ if (rq_prio < highest_prio) ++ continue; ++ ++ if (rq_prio > highest_prio || ++ deadline_after(rq->rq_deadline, latest_deadline)) { ++ latest_deadline = rq->rq_deadline; ++ highest_prio = rq_prio; ++ highest_prio_rq = rq; ++ } ++ } ++ ++ if (likely(highest_prio_rq)) { ++ if (can_preempt(p, highest_prio, highest_prio_rq->rq_deadline)) ++ resched_task(highest_prio_rq->curr); ++ } ++} ++#else /* CONFIG_SMP */ ++static inline bool needs_other_cpu(struct task_struct *p, int cpu) ++{ ++ return false; ++} ++ ++static void try_preempt(struct task_struct *p, struct rq *this_rq) ++{ ++ if (p->policy == SCHED_IDLEPRIO) ++ return; ++ if (can_preempt(p, uprq->rq_prio, uprq->rq_deadline)) ++ resched_task(uprq->curr); ++} ++#endif /* CONFIG_SMP */ ++ ++static void ++ttwu_stat(struct task_struct *p, int cpu, int wake_flags) ++{ ++#ifdef CONFIG_SCHEDSTATS ++ struct rq *rq = this_rq(); ++ ++#ifdef CONFIG_SMP ++ int this_cpu = smp_processor_id(); ++ ++ if (cpu == this_cpu) ++ schedstat_inc(rq, ttwu_local); ++ else { ++ struct sched_domain *sd; ++ ++ rcu_read_lock(); ++ for_each_domain(this_cpu, sd) { ++ if (cpumask_test_cpu(cpu, sched_domain_span(sd))) { ++ schedstat_inc(sd, ttwu_wake_remote); ++ break; ++ } ++ } ++ rcu_read_unlock(); ++ } ++ ++#endif /* CONFIG_SMP */ ++ ++ schedstat_inc(rq, ttwu_count); ++#endif /* CONFIG_SCHEDSTATS */ ++} ++ ++static inline void ttwu_activate(struct task_struct *p, struct rq *rq, ++ bool is_sync) ++{ ++ activate_task(p, rq); ++ ++ /* ++ * Sync wakeups (i.e. those types of wakeups where the waker ++ * has indicated that it will leave the CPU in short order) ++ * don't trigger a preemption if there are no idle cpus, ++ * instead waiting for current to deschedule. ++ */ ++ if (!is_sync || suitable_idle_cpus(p)) ++ try_preempt(p, rq); ++} ++ ++static inline void ttwu_post_activation(struct task_struct *p, struct rq *rq, ++ bool success) ++{ ++ trace_sched_wakeup(p, success); ++ p->state = TASK_RUNNING; ++ ++ /* ++ * if a worker is waking up, notify workqueue. Note that on BFS, we ++ * don't really know what cpu it will be, so we fake it for ++ * wq_worker_waking_up :/ ++ */ ++ if ((p->flags & PF_WQ_WORKER) && success) ++ wq_worker_waking_up(p, cpu_of(rq)); ++} ++ ++#ifdef CONFIG_SMP ++static void ++ttwu_do_activate(struct rq *rq, struct task_struct *p, int wake_flags) ++{ ++ ttwu_activate(p, rq, false); ++ ttwu_post_activation(p, rq, true); ++} ++ ++static void sched_ttwu_pending(void) ++{ ++ struct rq *rq = this_rq(); ++ struct llist_node *llist = llist_del_all(&rq->wake_list); ++ struct task_struct *p; ++ ++ grq_lock(); ++ ++ while (llist) { ++ p = llist_entry(llist, struct task_struct, wake_entry); ++ llist = llist_next(llist); ++ ttwu_do_activate(rq, p, 0); ++ } ++ ++ grq_unlock(); ++} ++ ++void scheduler_ipi(void) ++{ ++ if (llist_empty(&this_rq()->wake_list)) ++ return; ++ ++ /* ++ * Not all reschedule IPI handlers call irq_enter/irq_exit, since ++ * traditionally all their work was done from the interrupt return ++ * path. Now that we actually do some work, we need to make sure ++ * we do call them. ++ * ++ * Some archs already do call them, luckily irq_enter/exit nest ++ * properly. ++ * ++ * Arguably we should visit all archs and update all handlers, ++ * however a fair share of IPIs are still resched only so this would ++ * somewhat pessimize the simple resched case. ++ */ ++ irq_enter(); ++ sched_ttwu_pending(); ++ ++ irq_exit(); ++} ++#endif /* CONFIG_SMP */ ++ ++/* ++ * wake flags ++ */ ++#define WF_SYNC 0x01 /* waker goes to sleep after wakeup */ ++#define WF_FORK 0x02 /* child wakeup after fork */ ++#define WF_MIGRATED 0x4 /* internal use, task got migrated */ ++ ++/*** ++ * try_to_wake_up - wake up a thread ++ * @p: the thread to be awakened ++ * @state: the mask of task states that can be woken ++ * @wake_flags: wake modifier flags (WF_*) ++ * ++ * Put it on the run-queue if it's not already there. The "current" ++ * thread is always on the run-queue (except when the actual ++ * re-schedule is in progress), and as such you're allowed to do ++ * the simpler "current->state = TASK_RUNNING" to mark yourself ++ * runnable without the overhead of this. ++ * ++ * Return: %true if @p was woken up, %false if it was already running. ++ * or @state didn't match @p's state. ++ */ ++static bool try_to_wake_up(struct task_struct *p, unsigned int state, ++ int wake_flags) ++{ ++ bool success = false; ++ unsigned long flags; ++ struct rq *rq; ++ int cpu; ++ ++ get_cpu(); ++ ++ /* ++ * If we are going to wake up a thread waiting for CONDITION we ++ * need to ensure that CONDITION=1 done by the caller can not be ++ * reordered with p->state check below. This pairs with mb() in ++ * set_current_state() the waiting thread does. ++ */ ++ smp_mb__before_spinlock(); ++ ++ /* ++ * No need to do time_lock_grq as we only need to update the rq clock ++ * if we activate the task ++ */ ++ rq = task_grq_lock(p, &flags); ++ cpu = task_cpu(p); ++ ++ /* state is a volatile long, どうして、分からない */ ++ if (!((unsigned int)p->state & state)) ++ goto out_unlock; ++ ++ if (task_queued(p) || task_running(p)) ++ goto out_running; ++ ++ ttwu_activate(p, rq, wake_flags & WF_SYNC); ++ success = true; ++ ++out_running: ++ ttwu_post_activation(p, rq, success); ++out_unlock: ++ task_grq_unlock(&flags); ++ ++ ttwu_stat(p, cpu, wake_flags); ++ ++ put_cpu(); ++ ++ return success; ++} ++ ++/** ++ * try_to_wake_up_local - try to wake up a local task with grq lock held ++ * @p: the thread to be awakened ++ * ++ * Put @p on the run-queue if it's not already there. The caller must ++ * ensure that grq is locked and, @p is not the current task. ++ * grq stays locked over invocation. ++ */ ++static void try_to_wake_up_local(struct task_struct *p) ++{ ++ struct rq *rq = task_rq(p); ++ bool success = false; ++ ++ lockdep_assert_held(&grq.lock); ++ ++ if (!(p->state & TASK_NORMAL)) ++ return; ++ ++ if (!task_queued(p)) { ++ if (likely(!task_running(p))) { ++ schedstat_inc(rq, ttwu_count); ++ schedstat_inc(rq, ttwu_local); ++ } ++ ttwu_activate(p, rq, false); ++ ttwu_stat(p, smp_processor_id(), 0); ++ success = true; ++ } ++ ttwu_post_activation(p, rq, success); ++} ++ ++/** ++ * wake_up_process - Wake up a specific process ++ * @p: The process to be woken up. ++ * ++ * Attempt to wake up the nominated process and move it to the set of runnable ++ * processes. ++ * ++ * Return: 1 if the process was woken up, 0 if it was already running. ++ * ++ * It may be assumed that this function implies a write memory barrier before ++ * changing the task state if and only if any tasks are woken up. ++ */ ++int wake_up_process(struct task_struct *p) ++{ ++ WARN_ON(task_is_stopped_or_traced(p)); ++ return try_to_wake_up(p, TASK_NORMAL, 0); ++} ++EXPORT_SYMBOL(wake_up_process); ++ ++int wake_up_state(struct task_struct *p, unsigned int state) ++{ ++ return try_to_wake_up(p, state, 0); ++} ++ ++static void time_slice_expired(struct task_struct *p); ++ ++/* ++ * Perform scheduler related setup for a newly forked process p. ++ * p is forked by current. ++ */ ++void sched_fork(struct task_struct *p) ++{ ++#ifdef CONFIG_PREEMPT_NOTIFIERS ++ INIT_HLIST_HEAD(&p->preempt_notifiers); ++#endif ++ /* ++ * The process state is set to the same value of the process executing ++ * do_fork() code. That is running. This guarantees that nobody will ++ * actually run it, and a signal or other external event cannot wake ++ * it up and insert it on the runqueue either. ++ */ ++ ++ /* Should be reset in fork.c but done here for ease of bfs patching */ ++ p->utime = ++ p->stime = ++ p->utimescaled = ++ p->stimescaled = ++ p->sched_time = ++ p->stime_pc = ++ p->utime_pc = 0; ++ ++ /* ++ * Revert to default priority/policy on fork if requested. ++ */ ++ if (unlikely(p->sched_reset_on_fork)) { ++ if (p->policy == SCHED_FIFO || p->policy == SCHED_RR) { ++ p->policy = SCHED_NORMAL; ++ p->normal_prio = normal_prio(p); ++ } ++ ++ if (PRIO_TO_NICE(p->static_prio) < 0) { ++ p->static_prio = NICE_TO_PRIO(0); ++ p->normal_prio = p->static_prio; ++ } ++ ++ /* ++ * We don't need the reset flag anymore after the fork. It has ++ * fulfilled its duty: ++ */ ++ p->sched_reset_on_fork = 0; ++ } ++ ++ INIT_LIST_HEAD(&p->run_list); ++#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) ++ if (unlikely(sched_info_on())) ++ memset(&p->sched_info, 0, sizeof(p->sched_info)); ++#endif ++ p->on_cpu = false; ++ clear_sticky(p); ++ ++#ifdef CONFIG_PREEMPT_COUNT ++ /* Want to start with kernel preemption disabled. */ ++ task_thread_info(p)->preempt_count = 1; ++#endif ++} ++ ++/* ++ * wake_up_new_task - wake up a newly created task for the first time. ++ * ++ * This function will do some initial scheduler statistics housekeeping ++ * that must be done for every newly created context, then puts the task ++ * on the runqueue and wakes it. ++ */ ++void wake_up_new_task(struct task_struct *p) ++{ ++ struct task_struct *parent; ++ unsigned long flags; ++ struct rq *rq; ++ ++ parent = p->parent; ++ rq = task_grq_lock(p, &flags); ++ ++ /* ++ * Reinit new task deadline as its creator deadline could have changed ++ * since call to dup_task_struct(). ++ */ ++ p->deadline = rq->rq_deadline; ++ ++ /* ++ * If the task is a new process, current and parent are the same. If ++ * the task is a new thread in the thread group, it will have much more ++ * in common with current than with the parent. ++ */ ++ set_task_cpu(p, task_cpu(rq->curr)); ++ ++ /* ++ * Make sure we do not leak PI boosting priority to the child. ++ */ ++ p->prio = rq->curr->normal_prio; ++ ++ activate_task(p, rq); ++ trace_sched_wakeup_new(p, 1); ++ if (unlikely(p->policy == SCHED_FIFO)) ++ goto after_ts_init; ++ ++ /* ++ * Share the timeslice between parent and child, thus the ++ * total amount of pending timeslices in the system doesn't change, ++ * resulting in more scheduling fairness. If it's negative, it won't ++ * matter since that's the same as being 0. current's time_slice is ++ * actually in rq_time_slice when it's running, as is its last_ran ++ * value. rq->rq_deadline is only modified within schedule() so it ++ * is always equal to current->deadline. ++ */ ++ p->last_ran = rq->rq_last_ran; ++ if (likely(rq->rq_time_slice >= RESCHED_US * 2)) { ++ rq->rq_time_slice /= 2; ++ p->time_slice = rq->rq_time_slice; ++after_ts_init: ++ if (rq->curr == parent && !suitable_idle_cpus(p)) { ++ /* ++ * The VM isn't cloned, so we're in a good position to ++ * do child-runs-first in anticipation of an exec. This ++ * usually avoids a lot of COW overhead. ++ */ ++ set_tsk_need_resched(parent); ++ } else ++ try_preempt(p, rq); ++ } else { ++ if (rq->curr == parent) { ++ /* ++ * Forking task has run out of timeslice. Reschedule it and ++ * start its child with a new time slice and deadline. The ++ * child will end up running first because its deadline will ++ * be slightly earlier. ++ */ ++ rq->rq_time_slice = 0; ++ set_tsk_need_resched(parent); ++ } ++ time_slice_expired(p); ++ } ++ task_grq_unlock(&flags); ++} ++ ++#ifdef CONFIG_PREEMPT_NOTIFIERS ++ ++/** ++ * preempt_notifier_register - tell me when current is being preempted & rescheduled ++ * @notifier: notifier struct to register ++ */ ++void preempt_notifier_register(struct preempt_notifier *notifier) ++{ ++ hlist_add_head(¬ifier->link, ¤t->preempt_notifiers); ++} ++EXPORT_SYMBOL_GPL(preempt_notifier_register); ++ ++/** ++ * preempt_notifier_unregister - no longer interested in preemption notifications ++ * @notifier: notifier struct to unregister ++ * ++ * This is safe to call from within a preemption notifier. ++ */ ++void preempt_notifier_unregister(struct preempt_notifier *notifier) ++{ ++ hlist_del(¬ifier->link); ++} ++EXPORT_SYMBOL_GPL(preempt_notifier_unregister); ++ ++static void fire_sched_in_preempt_notifiers(struct task_struct *curr) ++{ ++ struct preempt_notifier *notifier; ++ ++ hlist_for_each_entry(notifier, &curr->preempt_notifiers, link) ++ notifier->ops->sched_in(notifier, raw_smp_processor_id()); ++} ++ ++static void ++fire_sched_out_preempt_notifiers(struct task_struct *curr, ++ struct task_struct *next) ++{ ++ struct preempt_notifier *notifier; ++ ++ hlist_for_each_entry(notifier, &curr->preempt_notifiers, link) ++ notifier->ops->sched_out(notifier, next); ++} ++ ++#else /* !CONFIG_PREEMPT_NOTIFIERS */ ++ ++static void fire_sched_in_preempt_notifiers(struct task_struct *curr) ++{ ++} ++ ++static void ++fire_sched_out_preempt_notifiers(struct task_struct *curr, ++ struct task_struct *next) ++{ ++} ++ ++#endif /* CONFIG_PREEMPT_NOTIFIERS */ ++ ++/** ++ * prepare_task_switch - prepare to switch tasks ++ * @rq: the runqueue preparing to switch ++ * @next: the task we are going to switch to. ++ * ++ * This is called with the rq lock held and interrupts off. It must ++ * be paired with a subsequent finish_task_switch after the context ++ * switch. ++ * ++ * prepare_task_switch sets up locking and calls architecture specific ++ * hooks. ++ */ ++static inline void ++prepare_task_switch(struct rq *rq, struct task_struct *prev, ++ struct task_struct *next) ++{ ++ sched_info_switch(prev, next); ++ perf_event_task_sched_out(prev, next); ++ fire_sched_out_preempt_notifiers(prev, next); ++ prepare_lock_switch(rq, next); ++ prepare_arch_switch(next); ++ trace_sched_switch(prev, next); ++} ++ ++/** ++ * finish_task_switch - clean up after a task-switch ++ * @rq: runqueue associated with task-switch ++ * @prev: the thread we just switched away from. ++ * ++ * finish_task_switch must be called after the context switch, paired ++ * with a prepare_task_switch call before the context switch. ++ * finish_task_switch will reconcile locking set up by prepare_task_switch, ++ * and do any other architecture-specific cleanup actions. ++ * ++ * Note that we may have delayed dropping an mm in context_switch(). If ++ * so, we finish that here outside of the runqueue lock. (Doing it ++ * with the lock held can cause deadlocks; see schedule() for ++ * details.) ++ */ ++static inline void finish_task_switch(struct rq *rq, struct task_struct *prev) ++ __releases(grq.lock) ++{ ++ struct mm_struct *mm = rq->prev_mm; ++ long prev_state; ++ ++ rq->prev_mm = NULL; ++ ++ /* ++ * A task struct has one reference for the use as "current". ++ * If a task dies, then it sets TASK_DEAD in tsk->state and calls ++ * schedule one last time. The schedule call will never return, and ++ * the scheduled task must drop that reference. ++ * The test for TASK_DEAD must occur while the runqueue locks are ++ * still held, otherwise prev could be scheduled on another cpu, die ++ * there before we look at prev->state, and then the reference would ++ * be dropped twice. ++ * Manfred Spraul ++ */ ++ prev_state = prev->state; ++ vtime_task_switch(prev); ++ finish_arch_switch(prev); ++ perf_event_task_sched_in(prev, current); ++ finish_lock_switch(rq, prev); ++ finish_arch_post_lock_switch(); ++ ++ fire_sched_in_preempt_notifiers(current); ++ if (mm) ++ mmdrop(mm); ++ if (unlikely(prev_state == TASK_DEAD)) { ++ /* ++ * Remove function-return probe instances associated with this ++ * task and put them back on the free list. ++ */ ++ kprobe_flush_task(prev); ++ put_task_struct(prev); ++ } ++} ++ ++/** ++ * schedule_tail - first thing a freshly forked thread must call. ++ * @prev: the thread we just switched away from. ++ */ ++asmlinkage void schedule_tail(struct task_struct *prev) ++ __releases(grq.lock) ++{ ++ struct rq *rq = this_rq(); ++ ++ finish_task_switch(rq, prev); ++#ifdef __ARCH_WANT_UNLOCKED_CTXSW ++ /* In this case, finish_task_switch does not reenable preemption */ ++ preempt_enable(); ++#endif ++ if (current->set_child_tid) ++ put_user(current->pid, current->set_child_tid); ++} ++ ++/* ++ * context_switch - switch to the new MM and the new ++ * thread's register state. ++ */ ++static inline void ++context_switch(struct rq *rq, struct task_struct *prev, ++ struct task_struct *next) ++{ ++ struct mm_struct *mm, *oldmm; ++ ++ prepare_task_switch(rq, prev, next); ++ ++ mm = next->mm; ++ oldmm = prev->active_mm; ++ /* ++ * For paravirt, this is coupled with an exit in switch_to to ++ * combine the page table reload and the switch backend into ++ * one hypercall. ++ */ ++ arch_start_context_switch(prev); ++ ++ if (!mm) { ++ next->active_mm = oldmm; ++ atomic_inc(&oldmm->mm_count); ++ enter_lazy_tlb(oldmm, next); ++ } else ++ switch_mm(oldmm, mm, next); ++ ++ if (!prev->mm) { ++ prev->active_mm = NULL; ++ rq->prev_mm = oldmm; ++ } ++ /* ++ * Since the runqueue lock will be released by the next ++ * task (which is an invalid locking op but in the case ++ * of the scheduler it's an obvious special-case), so we ++ * do an early lockdep release here: ++ */ ++#ifndef __ARCH_WANT_UNLOCKED_CTXSW ++ spin_release(&grq.lock.dep_map, 1, _THIS_IP_); ++#endif ++ ++ /* Here we just switch the register state and the stack. */ ++ context_tracking_task_switch(prev, next); ++ switch_to(prev, next, prev); ++ ++ barrier(); ++ /* ++ * this_rq must be evaluated again because prev may have moved ++ * CPUs since it called schedule(), thus the 'rq' on its stack ++ * frame will be invalid. ++ */ ++ finish_task_switch(this_rq(), prev); ++} ++ ++/* ++ * nr_running, nr_uninterruptible and nr_context_switches: ++ * ++ * externally visible scheduler statistics: current number of runnable ++ * threads, total number of context switches performed since bootup. All are ++ * measured without grabbing the grq lock but the occasional inaccurate result ++ * doesn't matter so long as it's positive. ++ */ ++unsigned long nr_running(void) ++{ ++ long nr = grq.nr_running; ++ ++ if (unlikely(nr < 0)) ++ nr = 0; ++ return (unsigned long)nr; ++} ++ ++static unsigned long nr_uninterruptible(void) ++{ ++ long nu = grq.nr_uninterruptible; ++ ++ if (unlikely(nu < 0)) ++ nu = 0; ++ return nu; ++} ++ ++unsigned long long nr_context_switches(void) ++{ ++ long long ns = grq.nr_switches; ++ ++ /* This is of course impossible */ ++ if (unlikely(ns < 0)) ++ ns = 1; ++ return (unsigned long long)ns; ++} ++ ++unsigned long nr_iowait(void) ++{ ++ unsigned long i, sum = 0; ++ ++ for_each_possible_cpu(i) ++ sum += atomic_read(&cpu_rq(i)->nr_iowait); ++ ++ return sum; ++} ++ ++unsigned long nr_iowait_cpu(int cpu) ++{ ++ struct rq *this = cpu_rq(cpu); ++ return atomic_read(&this->nr_iowait); ++} ++ ++unsigned long nr_active(void) ++{ ++ return nr_running() + nr_uninterruptible(); ++} ++ ++/* Beyond a task running on this CPU, load is equal everywhere on BFS */ ++unsigned long this_cpu_load(void) ++{ ++ return this_rq()->rq_running + ++ ((queued_notrunning() + nr_uninterruptible()) / grq.noc); ++} ++ ++/* Variables and functions for calc_load */ ++static unsigned long calc_load_update; ++unsigned long avenrun[3]; ++EXPORT_SYMBOL(avenrun); ++ ++/** ++ * get_avenrun - get the load average array ++ * @loads: pointer to dest load array ++ * @offset: offset to add ++ * @shift: shift count to shift the result left ++ * ++ * These values are estimates at best, so no need for locking. ++ */ ++void get_avenrun(unsigned long *loads, unsigned long offset, int shift) ++{ ++ loads[0] = (avenrun[0] + offset) << shift; ++ loads[1] = (avenrun[1] + offset) << shift; ++ loads[2] = (avenrun[2] + offset) << shift; ++} ++ ++static unsigned long ++calc_load(unsigned long load, unsigned long exp, unsigned long active) ++{ ++ load *= exp; ++ load += active * (FIXED_1 - exp); ++ return load >> FSHIFT; ++} ++ ++/* ++ * calc_load - update the avenrun load estimates every LOAD_FREQ seconds. ++ */ ++void calc_global_load(unsigned long ticks) ++{ ++ long active; ++ ++ if (time_before(jiffies, calc_load_update)) ++ return; ++ active = nr_active() * FIXED_1; ++ ++ avenrun[0] = calc_load(avenrun[0], EXP_1, active); ++ avenrun[1] = calc_load(avenrun[1], EXP_5, active); ++ avenrun[2] = calc_load(avenrun[2], EXP_15, active); ++ ++ calc_load_update = jiffies + LOAD_FREQ; ++} ++ ++DEFINE_PER_CPU(struct kernel_stat, kstat); ++DEFINE_PER_CPU(struct kernel_cpustat, kernel_cpustat); ++ ++EXPORT_PER_CPU_SYMBOL(kstat); ++EXPORT_PER_CPU_SYMBOL(kernel_cpustat); ++ ++#ifdef CONFIG_IRQ_TIME_ACCOUNTING ++ ++/* ++ * There are no locks covering percpu hardirq/softirq time. ++ * They are only modified in account_system_vtime, on corresponding CPU ++ * with interrupts disabled. So, writes are safe. ++ * They are read and saved off onto struct rq in update_rq_clock(). ++ * This may result in other CPU reading this CPU's irq time and can ++ * race with irq/account_system_vtime on this CPU. We would either get old ++ * or new value with a side effect of accounting a slice of irq time to wrong ++ * task when irq is in progress while we read rq->clock. That is a worthy ++ * compromise in place of having locks on each irq in account_system_time. ++ */ ++static DEFINE_PER_CPU(u64, cpu_hardirq_time); ++static DEFINE_PER_CPU(u64, cpu_softirq_time); ++ ++static DEFINE_PER_CPU(u64, irq_start_time); ++static int sched_clock_irqtime; ++ ++void enable_sched_clock_irqtime(void) ++{ ++ sched_clock_irqtime = 1; ++} ++ ++void disable_sched_clock_irqtime(void) ++{ ++ sched_clock_irqtime = 0; ++} ++ ++#ifndef CONFIG_64BIT ++static DEFINE_PER_CPU(seqcount_t, irq_time_seq); ++ ++static inline void irq_time_write_begin(void) ++{ ++ __this_cpu_inc(irq_time_seq.sequence); ++ smp_wmb(); ++} ++ ++static inline void irq_time_write_end(void) ++{ ++ smp_wmb(); ++ __this_cpu_inc(irq_time_seq.sequence); ++} ++ ++static inline u64 irq_time_read(int cpu) ++{ ++ u64 irq_time; ++ unsigned seq; ++ ++ do { ++ seq = read_seqcount_begin(&per_cpu(irq_time_seq, cpu)); ++ irq_time = per_cpu(cpu_softirq_time, cpu) + ++ per_cpu(cpu_hardirq_time, cpu); ++ } while (read_seqcount_retry(&per_cpu(irq_time_seq, cpu), seq)); ++ ++ return irq_time; ++} ++#else /* CONFIG_64BIT */ ++static inline void irq_time_write_begin(void) ++{ ++} ++ ++static inline void irq_time_write_end(void) ++{ ++} ++ ++static inline u64 irq_time_read(int cpu) ++{ ++ return per_cpu(cpu_softirq_time, cpu) + per_cpu(cpu_hardirq_time, cpu); ++} ++#endif /* CONFIG_64BIT */ ++ ++/* ++ * Called before incrementing preempt_count on {soft,}irq_enter ++ * and before decrementing preempt_count on {soft,}irq_exit. ++ */ ++void irqtime_account_irq(struct task_struct *curr) ++{ ++ unsigned long flags; ++ s64 delta; ++ int cpu; ++ ++ if (!sched_clock_irqtime) ++ return; ++ ++ local_irq_save(flags); ++ ++ cpu = smp_processor_id(); ++ delta = sched_clock_cpu(cpu) - __this_cpu_read(irq_start_time); ++ __this_cpu_add(irq_start_time, delta); ++ ++ irq_time_write_begin(); ++ /* ++ * We do not account for softirq time from ksoftirqd here. ++ * We want to continue accounting softirq time to ksoftirqd thread ++ * in that case, so as not to confuse scheduler with a special task ++ * that do not consume any time, but still wants to run. ++ */ ++ if (hardirq_count()) ++ __this_cpu_add(cpu_hardirq_time, delta); ++ else if (in_serving_softirq() && curr != this_cpu_ksoftirqd()) ++ __this_cpu_add(cpu_softirq_time, delta); ++ ++ irq_time_write_end(); ++ local_irq_restore(flags); ++} ++EXPORT_SYMBOL_GPL(irqtime_account_irq); ++ ++#endif /* CONFIG_IRQ_TIME_ACCOUNTING */ ++ ++#ifdef CONFIG_PARAVIRT ++static inline u64 steal_ticks(u64 steal) ++{ ++ if (unlikely(steal > NSEC_PER_SEC)) ++ return div_u64(steal, TICK_NSEC); ++ ++ return __iter_div_u64_rem(steal, TICK_NSEC, &steal); ++} ++#endif ++ ++static void update_rq_clock_task(struct rq *rq, s64 delta) ++{ ++/* ++ * In theory, the compile should just see 0 here, and optimize out the call ++ * to sched_rt_avg_update. But I don't trust it... ++ */ ++#ifdef CONFIG_IRQ_TIME_ACCOUNTING ++ s64 irq_delta = irq_time_read(cpu_of(rq)) - rq->prev_irq_time; ++ ++ /* ++ * Since irq_time is only updated on {soft,}irq_exit, we might run into ++ * this case when a previous update_rq_clock() happened inside a ++ * {soft,}irq region. ++ * ++ * When this happens, we stop ->clock_task and only update the ++ * prev_irq_time stamp to account for the part that fit, so that a next ++ * update will consume the rest. This ensures ->clock_task is ++ * monotonic. ++ * ++ * It does however cause some slight miss-attribution of {soft,}irq ++ * time, a more accurate solution would be to update the irq_time using ++ * the current rq->clock timestamp, except that would require using ++ * atomic ops. ++ */ ++ if (irq_delta > delta) ++ irq_delta = delta; ++ ++ rq->prev_irq_time += irq_delta; ++ delta -= irq_delta; ++#endif ++#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING ++ if (static_key_false((¶virt_steal_rq_enabled))) { ++ s64 steal = paravirt_steal_clock(cpu_of(rq)); ++ u64 st; ++ ++ steal -= rq->prev_steal_time_rq; ++ ++ if (unlikely(steal > delta)) ++ steal = delta; ++ ++ st = steal_ticks(steal); ++ steal = st * TICK_NSEC; ++ ++ rq->prev_steal_time_rq += steal; ++ ++ delta -= steal; ++ } ++#endif ++ ++ rq->clock_task += delta; ++} ++ ++#ifndef nsecs_to_cputime ++# define nsecs_to_cputime(__nsecs) nsecs_to_jiffies(__nsecs) ++#endif ++ ++#ifdef CONFIG_IRQ_TIME_ACCOUNTING ++static void irqtime_account_hi_si(void) ++{ ++ u64 *cpustat = kcpustat_this_cpu->cpustat; ++ u64 latest_ns; ++ ++ latest_ns = nsecs_to_cputime64(this_cpu_read(cpu_hardirq_time)); ++ if (latest_ns > cpustat[CPUTIME_IRQ]) ++ cpustat[CPUTIME_IRQ] += (__force u64)cputime_one_jiffy; ++ ++ latest_ns = nsecs_to_cputime64(this_cpu_read(cpu_softirq_time)); ++ if (latest_ns > cpustat[CPUTIME_SOFTIRQ]) ++ cpustat[CPUTIME_SOFTIRQ] += (__force u64)cputime_one_jiffy; ++} ++#else /* CONFIG_IRQ_TIME_ACCOUNTING */ ++ ++#define sched_clock_irqtime (0) ++ ++static inline void irqtime_account_hi_si(void) ++{ ++} ++#endif /* CONFIG_IRQ_TIME_ACCOUNTING */ ++ ++static __always_inline bool steal_account_process_tick(void) ++{ ++#ifdef CONFIG_PARAVIRT ++ if (static_key_false(¶virt_steal_enabled)) { ++ u64 steal, st = 0; ++ ++ steal = paravirt_steal_clock(smp_processor_id()); ++ steal -= this_rq()->prev_steal_time; ++ ++ st = steal_ticks(steal); ++ this_rq()->prev_steal_time += st * TICK_NSEC; ++ ++ account_steal_time(st); ++ return st; ++ } ++#endif ++ return false; ++} ++ ++/* ++ * Accumulate raw cputime values of dead tasks (sig->[us]time) and live ++ * tasks (sum on group iteration) belonging to @tsk's group. ++ */ ++void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times) ++{ ++ struct signal_struct *sig = tsk->signal; ++ cputime_t utime, stime; ++ struct task_struct *t; ++ unsigned long flags; ++ ++ times->utime = sig->utime; ++ times->stime = sig->stime; ++ times->sum_exec_runtime = sig->sum_sched_runtime; ++ ++ rcu_read_lock(); ++ /* make sure we can trust tsk->thread_group list */ ++ if (!likely(pid_alive(tsk))) ++ goto out; ++ ++ t = tsk; ++ grq_lock_irqsave(&flags); ++ do { ++ task_cputime(t, &utime, &stime); ++ times->utime += utime; ++ times->stime += stime; ++ times->sum_exec_runtime += do_task_sched_runtime(t); ++ } while_each_thread(tsk, t); ++ grq_unlock_irqrestore(&flags); ++out: ++ rcu_read_unlock(); ++} ++ ++/* ++ * On each tick, see what percentage of that tick was attributed to each ++ * component and add the percentage to the _pc values. Once a _pc value has ++ * accumulated one tick's worth, account for that. This means the total ++ * percentage of load components will always be 128 (pseudo 100) per tick. ++ */ ++static void pc_idle_time(struct rq *rq, struct task_struct *idle, unsigned long pc) ++{ ++ u64 *cpustat = kcpustat_this_cpu->cpustat; ++ ++ if (atomic_read(&rq->nr_iowait) > 0) { ++ rq->iowait_pc += pc; ++ if (rq->iowait_pc >= 128) { ++ cpustat[CPUTIME_IOWAIT] += (__force u64)cputime_one_jiffy * rq->iowait_pc / 128; ++ rq->iowait_pc %= 128; ++ } ++ } else { ++ rq->idle_pc += pc; ++ if (rq->idle_pc >= 128) { ++ cpustat[CPUTIME_IDLE] += (__force u64)cputime_one_jiffy * rq->idle_pc / 128; ++ rq->idle_pc %= 128; ++ } ++ } ++ acct_update_integrals(idle); ++} ++ ++static void ++pc_system_time(struct rq *rq, struct task_struct *p, int hardirq_offset, ++ unsigned long pc, unsigned long ns) ++{ ++ u64 *cpustat = kcpustat_this_cpu->cpustat; ++ cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy); ++ ++ p->stime_pc += pc; ++ if (p->stime_pc >= 128) { ++ int jiffs = p->stime_pc / 128; ++ ++ p->stime_pc %= 128; ++ p->stime += (__force u64)cputime_one_jiffy * jiffs; ++ p->stimescaled += one_jiffy_scaled * jiffs; ++ account_group_system_time(p, cputime_one_jiffy * jiffs); ++ } ++ p->sched_time += ns; ++ account_group_exec_runtime(p, ns); ++ ++ if (hardirq_count() - hardirq_offset) { ++ rq->irq_pc += pc; ++ if (rq->irq_pc >= 128) { ++ cpustat[CPUTIME_IRQ] += (__force u64)cputime_one_jiffy * rq->irq_pc / 128; ++ rq->irq_pc %= 128; ++ } ++ } else if (in_serving_softirq()) { ++ rq->softirq_pc += pc; ++ if (rq->softirq_pc >= 128) { ++ cpustat[CPUTIME_SOFTIRQ] += (__force u64)cputime_one_jiffy * rq->softirq_pc / 128; ++ rq->softirq_pc %= 128; ++ } ++ } else { ++ rq->system_pc += pc; ++ if (rq->system_pc >= 128) { ++ cpustat[CPUTIME_SYSTEM] += (__force u64)cputime_one_jiffy * rq->system_pc / 128; ++ rq->system_pc %= 128; ++ } ++ } ++ acct_update_integrals(p); ++} ++ ++static void pc_user_time(struct rq *rq, struct task_struct *p, ++ unsigned long pc, unsigned long ns) ++{ ++ u64 *cpustat = kcpustat_this_cpu->cpustat; ++ cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy); ++ ++ p->utime_pc += pc; ++ if (p->utime_pc >= 128) { ++ int jiffs = p->utime_pc / 128; ++ ++ p->utime_pc %= 128; ++ p->utime += (__force u64)cputime_one_jiffy * jiffs; ++ p->utimescaled += one_jiffy_scaled * jiffs; ++ account_group_user_time(p, cputime_one_jiffy * jiffs); ++ } ++ p->sched_time += ns; ++ account_group_exec_runtime(p, ns); ++ ++ if (this_cpu_ksoftirqd() == p) { ++ /* ++ * ksoftirqd time do not get accounted in cpu_softirq_time. ++ * So, we have to handle it separately here. ++ */ ++ rq->softirq_pc += pc; ++ if (rq->softirq_pc >= 128) { ++ cpustat[CPUTIME_SOFTIRQ] += (__force u64)cputime_one_jiffy * rq->softirq_pc / 128; ++ rq->softirq_pc %= 128; ++ } ++ } ++ ++ if (TASK_NICE(p) > 0 || idleprio_task(p)) { ++ rq->nice_pc += pc; ++ if (rq->nice_pc >= 128) { ++ cpustat[CPUTIME_NICE] += (__force u64)cputime_one_jiffy * rq->nice_pc / 128; ++ rq->nice_pc %= 128; ++ } ++ } else { ++ rq->user_pc += pc; ++ if (rq->user_pc >= 128) { ++ cpustat[CPUTIME_USER] += (__force u64)cputime_one_jiffy * rq->user_pc / 128; ++ rq->user_pc %= 128; ++ } ++ } ++ acct_update_integrals(p); ++} ++ ++/* ++ * Convert nanoseconds to pseudo percentage of one tick. Use 128 for fast ++ * shifts instead of 100 ++ */ ++#define NS_TO_PC(NS) (NS * 128 / JIFFY_NS) ++ ++/* ++ * This is called on clock ticks. ++ * Bank in p->sched_time the ns elapsed since the last tick or switch. ++ * CPU scheduler quota accounting is also performed here in microseconds. ++ */ ++static void ++update_cpu_clock_tick(struct rq *rq, struct task_struct *p) ++{ ++ long account_ns = rq->clock_task - rq->rq_last_ran; ++ struct task_struct *idle = rq->idle; ++ unsigned long account_pc; ++ ++ if (unlikely(account_ns < 0) || steal_account_process_tick()) ++ goto ts_account; ++ ++ account_pc = NS_TO_PC(account_ns); ++ ++ /* Accurate tick timekeeping */ ++ if (user_mode(get_irq_regs())) ++ pc_user_time(rq, p, account_pc, account_ns); ++ else if (p != idle || (irq_count() != HARDIRQ_OFFSET)) ++ pc_system_time(rq, p, HARDIRQ_OFFSET, ++ account_pc, account_ns); ++ else ++ pc_idle_time(rq, idle, account_pc); ++ ++ if (sched_clock_irqtime) ++ irqtime_account_hi_si(); ++ ++ts_account: ++ /* time_slice accounting is done in usecs to avoid overflow on 32bit */ ++ if (rq->rq_policy != SCHED_FIFO && p != idle) { ++ s64 time_diff = rq->clock - rq->timekeep_clock; ++ ++ niffy_diff(&time_diff, 1); ++ rq->rq_time_slice -= NS_TO_US(time_diff); ++ } ++ ++ rq->rq_last_ran = rq->clock_task; ++ rq->timekeep_clock = rq->clock; ++} ++ ++/* ++ * This is called on context switches. ++ * Bank in p->sched_time the ns elapsed since the last tick or switch. ++ * CPU scheduler quota accounting is also performed here in microseconds. ++ */ ++static void ++update_cpu_clock_switch(struct rq *rq, struct task_struct *p) ++{ ++ long account_ns = rq->clock_task - rq->rq_last_ran; ++ struct task_struct *idle = rq->idle; ++ unsigned long account_pc; ++ ++ if (unlikely(account_ns < 0)) ++ goto ts_account; ++ ++ account_pc = NS_TO_PC(account_ns); ++ ++ /* Accurate subtick timekeeping */ ++ if (p != idle) { ++ pc_user_time(rq, p, account_pc, account_ns); ++ } ++ else ++ pc_idle_time(rq, idle, account_pc); ++ ++ts_account: ++ /* time_slice accounting is done in usecs to avoid overflow on 32bit */ ++ if (rq->rq_policy != SCHED_FIFO && p != idle) { ++ s64 time_diff = rq->clock - rq->timekeep_clock; ++ ++ niffy_diff(&time_diff, 1); ++ rq->rq_time_slice -= NS_TO_US(time_diff); ++ } ++ ++ rq->rq_last_ran = rq->clock_task; ++ rq->timekeep_clock = rq->clock; ++} ++ ++/* ++ * Return any ns on the sched_clock that have not yet been accounted in ++ * @p in case that task is currently running. ++ * ++ * Called with task_grq_lock() held. ++ */ ++static u64 do_task_delta_exec(struct task_struct *p, struct rq *rq) ++{ ++ u64 ns = 0; ++ ++ if (p == rq->curr) { ++ update_clocks(rq); ++ ns = rq->clock_task - rq->rq_last_ran; ++ if (unlikely((s64)ns < 0)) ++ ns = 0; ++ } ++ ++ return ns; ++} ++ ++unsigned long long task_delta_exec(struct task_struct *p) ++{ ++ unsigned long flags; ++ struct rq *rq; ++ u64 ns; ++ ++ rq = task_grq_lock(p, &flags); ++ ns = do_task_delta_exec(p, rq); ++ task_grq_unlock(&flags); ++ ++ return ns; ++} ++ ++/* ++ * Return accounted runtime for the task. ++ * Return separately the current's pending runtime that have not been ++ * accounted yet. ++ * ++ * grq lock already acquired. ++ */ ++unsigned long long do_task_sched_runtime(struct task_struct *p) ++{ ++ struct rq *rq; ++ u64 ns; ++ ++ rq = task_rq(p); ++ ns = p->sched_time + do_task_delta_exec(p,rq); ++ ++ return ns; ++} ++ ++/* ++ * Return accounted runtime for the task. ++ * Return separately the current's pending runtime that have not been ++ * accounted yet. ++ * ++ */ ++unsigned long long task_sched_runtime(struct task_struct *p) ++{ ++ unsigned long flags; ++ struct rq *rq; ++ u64 ns; ++ ++ rq = task_grq_lock(p, &flags); ++ ns = p->sched_time + do_task_delta_exec(p, rq); ++ task_grq_unlock(&flags); ++ ++ return ns; ++} ++ ++/* Compatibility crap */ ++void account_user_time(struct task_struct *p, cputime_t cputime, ++ cputime_t cputime_scaled) ++{ ++} ++ ++void account_idle_time(cputime_t cputime) ++{ ++} ++ ++void update_cpu_load_nohz(void) ++{ ++} ++ ++#ifdef CONFIG_NO_HZ_COMMON ++void calc_load_enter_idle(void) ++{ ++} ++ ++void calc_load_exit_idle(void) ++{ ++} ++#endif /* CONFIG_NO_HZ_COMMON */ ++ ++/* ++ * Account guest cpu time to a process. ++ * @p: the process that the cpu time gets accounted to ++ * @cputime: the cpu time spent in virtual machine since the last update ++ * @cputime_scaled: cputime scaled by cpu frequency ++ */ ++static void account_guest_time(struct task_struct *p, cputime_t cputime, ++ cputime_t cputime_scaled) ++{ ++ u64 *cpustat = kcpustat_this_cpu->cpustat; ++ ++ /* Add guest time to process. */ ++ p->utime += (__force u64)cputime; ++ p->utimescaled += (__force u64)cputime_scaled; ++ account_group_user_time(p, cputime); ++ p->gtime += (__force u64)cputime; ++ ++ /* Add guest time to cpustat. */ ++ if (TASK_NICE(p) > 0) { ++ cpustat[CPUTIME_NICE] += (__force u64)cputime; ++ cpustat[CPUTIME_GUEST_NICE] += (__force u64)cputime; ++ } else { ++ cpustat[CPUTIME_USER] += (__force u64)cputime; ++ cpustat[CPUTIME_GUEST] += (__force u64)cputime; ++ } ++} ++ ++/* ++ * Account system cpu time to a process and desired cpustat field ++ * @p: the process that the cpu time gets accounted to ++ * @cputime: the cpu time spent in kernel space since the last update ++ * @cputime_scaled: cputime scaled by cpu frequency ++ * @target_cputime64: pointer to cpustat field that has to be updated ++ */ ++static inline ++void __account_system_time(struct task_struct *p, cputime_t cputime, ++ cputime_t cputime_scaled, cputime64_t *target_cputime64) ++{ ++ /* Add system time to process. */ ++ p->stime += (__force u64)cputime; ++ p->stimescaled += (__force u64)cputime_scaled; ++ account_group_system_time(p, cputime); ++ ++ /* Add system time to cpustat. */ ++ *target_cputime64 += (__force u64)cputime; ++ ++ /* Account for system time used */ ++ acct_update_integrals(p); ++} ++ ++/* ++ * Account system cpu time to a process. ++ * @p: the process that the cpu time gets accounted to ++ * @hardirq_offset: the offset to subtract from hardirq_count() ++ * @cputime: the cpu time spent in kernel space since the last update ++ * @cputime_scaled: cputime scaled by cpu frequency ++ * This is for guest only now. ++ */ ++void account_system_time(struct task_struct *p, int hardirq_offset, ++ cputime_t cputime, cputime_t cputime_scaled) ++{ ++ ++ if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) ++ account_guest_time(p, cputime, cputime_scaled); ++} ++ ++/* ++ * Account for involuntary wait time. ++ * @steal: the cpu time spent in involuntary wait ++ */ ++void account_steal_time(cputime_t cputime) ++{ ++ u64 *cpustat = kcpustat_this_cpu->cpustat; ++ ++ cpustat[CPUTIME_STEAL] += (__force u64)cputime; ++} ++ ++/* ++ * Account for idle time. ++ * @cputime: the cpu time spent in idle wait ++ */ ++static void account_idle_times(cputime_t cputime) ++{ ++ u64 *cpustat = kcpustat_this_cpu->cpustat; ++ struct rq *rq = this_rq(); ++ ++ if (atomic_read(&rq->nr_iowait) > 0) ++ cpustat[CPUTIME_IOWAIT] += (__force u64)cputime; ++ else ++ cpustat[CPUTIME_IDLE] += (__force u64)cputime; ++} ++ ++#ifndef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE ++ ++void account_process_tick(struct task_struct *p, int user_tick) ++{ ++} ++ ++/* ++ * Account multiple ticks of steal time. ++ * @p: the process from which the cpu time has been stolen ++ * @ticks: number of stolen ticks ++ */ ++void account_steal_ticks(unsigned long ticks) ++{ ++ account_steal_time(jiffies_to_cputime(ticks)); ++} ++ ++/* ++ * Account multiple ticks of idle time. ++ * @ticks: number of stolen ticks ++ */ ++void account_idle_ticks(unsigned long ticks) ++{ ++ account_idle_times(jiffies_to_cputime(ticks)); ++} ++#endif ++ ++static inline void grq_iso_lock(void) ++ __acquires(grq.iso_lock) ++{ ++ raw_spin_lock(&grq.iso_lock); ++} ++ ++static inline void grq_iso_unlock(void) ++ __releases(grq.iso_lock) ++{ ++ raw_spin_unlock(&grq.iso_lock); ++} ++ ++/* ++ * Functions to test for when SCHED_ISO tasks have used their allocated ++ * quota as real time scheduling and convert them back to SCHED_NORMAL. ++ * Where possible, the data is tested lockless, to avoid grabbing iso_lock ++ * because the occasional inaccurate result won't matter. However the ++ * tick data is only ever modified under lock. iso_refractory is only simply ++ * set to 0 or 1 so it's not worth grabbing the lock yet again for that. ++ */ ++static bool set_iso_refractory(void) ++{ ++ grq.iso_refractory = true; ++ return grq.iso_refractory; ++} ++ ++static bool clear_iso_refractory(void) ++{ ++ grq.iso_refractory = false; ++ return grq.iso_refractory; ++} ++ ++/* ++ * Test if SCHED_ISO tasks have run longer than their alloted period as RT ++ * tasks and set the refractory flag if necessary. There is 10% hysteresis ++ * for unsetting the flag. 115/128 is ~90/100 as a fast shift instead of a ++ * slow division. ++ */ ++static bool test_ret_isorefractory(struct rq *rq) ++{ ++ if (likely(!grq.iso_refractory)) { ++ if (grq.iso_ticks > ISO_PERIOD * sched_iso_cpu) ++ return set_iso_refractory(); ++ } else { ++ if (grq.iso_ticks < ISO_PERIOD * (sched_iso_cpu * 115 / 128)) ++ return clear_iso_refractory(); ++ } ++ return grq.iso_refractory; ++} ++ ++static void iso_tick(void) ++{ ++ grq_iso_lock(); ++ grq.iso_ticks += 100; ++ grq_iso_unlock(); ++} ++ ++/* No SCHED_ISO task was running so decrease rq->iso_ticks */ ++static inline void no_iso_tick(void) ++{ ++ if (grq.iso_ticks) { ++ grq_iso_lock(); ++ grq.iso_ticks -= grq.iso_ticks / ISO_PERIOD + 1; ++ if (unlikely(grq.iso_refractory && grq.iso_ticks < ++ ISO_PERIOD * (sched_iso_cpu * 115 / 128))) ++ clear_iso_refractory(); ++ grq_iso_unlock(); ++ } ++} ++ ++/* This manages tasks that have run out of timeslice during a scheduler_tick */ ++static void task_running_tick(struct rq *rq) ++{ ++ struct task_struct *p; ++ ++ /* ++ * If a SCHED_ISO task is running we increment the iso_ticks. In ++ * order to prevent SCHED_ISO tasks from causing starvation in the ++ * presence of true RT tasks we account those as iso_ticks as well. ++ */ ++ if ((rt_queue(rq) || (iso_queue(rq) && !grq.iso_refractory))) { ++ if (grq.iso_ticks <= (ISO_PERIOD * 128) - 128) ++ iso_tick(); ++ } else ++ no_iso_tick(); ++ ++ if (iso_queue(rq)) { ++ if (unlikely(test_ret_isorefractory(rq))) { ++ if (rq_running_iso(rq)) { ++ /* ++ * SCHED_ISO task is running as RT and limit ++ * has been hit. Force it to reschedule as ++ * SCHED_NORMAL by zeroing its time_slice ++ */ ++ rq->rq_time_slice = 0; ++ } ++ } ++ } ++ ++ /* SCHED_FIFO tasks never run out of timeslice. */ ++ if (rq->rq_policy == SCHED_FIFO) ++ return; ++ /* ++ * Tasks that were scheduled in the first half of a tick are not ++ * allowed to run into the 2nd half of the next tick if they will ++ * run out of time slice in the interim. Otherwise, if they have ++ * less than RESCHED_US μs of time slice left they will be rescheduled. ++ */ ++ if (rq->dither) { ++ if (rq->rq_time_slice > HALF_JIFFY_US) ++ return; ++ else ++ rq->rq_time_slice = 0; ++ } else if (rq->rq_time_slice >= RESCHED_US) ++ return; ++ ++ /* p->time_slice < RESCHED_US. We only modify task_struct under grq lock */ ++ p = rq->curr; ++ grq_lock(); ++ requeue_task(p); ++ set_tsk_need_resched(p); ++ grq_unlock(); ++} ++ ++/* ++ * This function gets called by the timer code, with HZ frequency. ++ * We call it with interrupts disabled. The data modified is all ++ * local to struct rq so we don't need to grab grq lock. ++ */ ++void scheduler_tick(void) ++{ ++ int cpu __maybe_unused = smp_processor_id(); ++ struct rq *rq = cpu_rq(cpu); ++ ++ sched_clock_tick(); ++ /* grq lock not grabbed, so only update rq clock */ ++ update_rq_clock(rq); ++ update_cpu_clock_tick(rq, rq->curr); ++ if (!rq_idle(rq)) ++ task_running_tick(rq); ++ else ++ no_iso_tick(); ++ rq->last_tick = rq->clock; ++ perf_event_task_tick(); ++} ++ ++notrace unsigned long get_parent_ip(unsigned long addr) ++{ ++ if (in_lock_functions(addr)) { ++ addr = CALLER_ADDR2; ++ if (in_lock_functions(addr)) ++ addr = CALLER_ADDR3; ++ } ++ return addr; ++} ++ ++#if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \ ++ defined(CONFIG_PREEMPT_TRACER)) ++void __kprobes add_preempt_count(int val) ++{ ++#ifdef CONFIG_DEBUG_PREEMPT ++ /* ++ * Underflow? ++ */ ++ if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0))) ++ return; ++#endif ++ preempt_count() += val; ++#ifdef CONFIG_DEBUG_PREEMPT ++ /* ++ * Spinlock count overflowing soon? ++ */ ++ DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >= ++ PREEMPT_MASK - 10); ++#endif ++ if (preempt_count() == val) ++ trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1)); ++} ++EXPORT_SYMBOL(add_preempt_count); ++ ++void __kprobes sub_preempt_count(int val) ++{ ++#ifdef CONFIG_DEBUG_PREEMPT ++ /* ++ * Underflow? ++ */ ++ if (DEBUG_LOCKS_WARN_ON(val > preempt_count())) ++ return; ++ /* ++ * Is the spinlock portion underflowing? ++ */ ++ if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) && ++ !(preempt_count() & PREEMPT_MASK))) ++ return; ++#endif ++ ++ if (preempt_count() == val) ++ trace_preempt_on(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1)); ++ preempt_count() -= val; ++} ++EXPORT_SYMBOL(sub_preempt_count); ++#endif ++ ++/* ++ * Deadline is "now" in niffies + (offset by priority). Setting the deadline ++ * is the key to everything. It distributes cpu fairly amongst tasks of the ++ * same nice value, it proportions cpu according to nice level, it means the ++ * task that last woke up the longest ago has the earliest deadline, thus ++ * ensuring that interactive tasks get low latency on wake up. The CPU ++ * proportion works out to the square of the virtual deadline difference, so ++ * this equation will give nice 19 3% CPU compared to nice 0. ++ */ ++static inline u64 prio_deadline_diff(int user_prio) ++{ ++ return (prio_ratios[user_prio] * rr_interval * (MS_TO_NS(1) / 128)); ++} ++ ++static inline u64 task_deadline_diff(struct task_struct *p) ++{ ++ return prio_deadline_diff(TASK_USER_PRIO(p)); ++} ++ ++static inline u64 static_deadline_diff(int static_prio) ++{ ++ return prio_deadline_diff(USER_PRIO(static_prio)); ++} ++ ++static inline int longest_deadline_diff(void) ++{ ++ return prio_deadline_diff(39); ++} ++ ++static inline int ms_longest_deadline_diff(void) ++{ ++ return NS_TO_MS(longest_deadline_diff()); ++} ++ ++/* ++ * The time_slice is only refilled when it is empty and that is when we set a ++ * new deadline. ++ */ ++static void time_slice_expired(struct task_struct *p) ++{ ++ p->time_slice = timeslice(); ++ p->deadline = grq.niffies + task_deadline_diff(p); ++} ++ ++/* ++ * Timeslices below RESCHED_US are considered as good as expired as there's no ++ * point rescheduling when there's so little time left. SCHED_BATCH tasks ++ * have been flagged be not latency sensitive and likely to be fully CPU ++ * bound so every time they're rescheduled they have their time_slice ++ * refilled, but get a new later deadline to have little effect on ++ * SCHED_NORMAL tasks. ++ ++ */ ++static inline void check_deadline(struct task_struct *p) ++{ ++ if (p->time_slice < RESCHED_US || batch_task(p)) ++ time_slice_expired(p); ++} ++ ++#define BITOP_WORD(nr) ((nr) / BITS_PER_LONG) ++ ++/* ++ * Scheduler queue bitmap specific find next bit. ++ */ ++static inline unsigned long ++next_sched_bit(const unsigned long *addr, unsigned long offset) ++{ ++ const unsigned long *p; ++ unsigned long result; ++ unsigned long size; ++ unsigned long tmp; ++ ++ size = PRIO_LIMIT; ++ if (offset >= size) ++ return size; ++ ++ p = addr + BITOP_WORD(offset); ++ result = offset & ~(BITS_PER_LONG-1); ++ size -= result; ++ offset %= BITS_PER_LONG; ++ if (offset) { ++ tmp = *(p++); ++ tmp &= (~0UL << offset); ++ if (size < BITS_PER_LONG) ++ goto found_first; ++ if (tmp) ++ goto found_middle; ++ size -= BITS_PER_LONG; ++ result += BITS_PER_LONG; ++ } ++ while (size & ~(BITS_PER_LONG-1)) { ++ if ((tmp = *(p++))) ++ goto found_middle; ++ result += BITS_PER_LONG; ++ size -= BITS_PER_LONG; ++ } ++ if (!size) ++ return result; ++ tmp = *p; ++ ++found_first: ++ tmp &= (~0UL >> (BITS_PER_LONG - size)); ++ if (tmp == 0UL) /* Are any bits set? */ ++ return result + size; /* Nope. */ ++found_middle: ++ return result + __ffs(tmp); ++} ++ ++/* ++ * O(n) lookup of all tasks in the global runqueue. The real brainfuck ++ * of lock contention and O(n). It's not really O(n) as only the queued, ++ * but not running tasks are scanned, and is O(n) queued in the worst case ++ * scenario only because the right task can be found before scanning all of ++ * them. ++ * Tasks are selected in this order: ++ * Real time tasks are selected purely by their static priority and in the ++ * order they were queued, so the lowest value idx, and the first queued task ++ * of that priority value is chosen. ++ * If no real time tasks are found, the SCHED_ISO priority is checked, and ++ * all SCHED_ISO tasks have the same priority value, so they're selected by ++ * the earliest deadline value. ++ * If no SCHED_ISO tasks are found, SCHED_NORMAL tasks are selected by the ++ * earliest deadline. ++ * Finally if no SCHED_NORMAL tasks are found, SCHED_IDLEPRIO tasks are ++ * selected by the earliest deadline. ++ */ ++static inline struct ++task_struct *earliest_deadline_task(struct rq *rq, int cpu, struct task_struct *idle) ++{ ++ struct task_struct *edt = NULL; ++ unsigned long idx = -1; ++ ++ do { ++ struct list_head *queue; ++ struct task_struct *p; ++ u64 earliest_deadline; ++ ++ idx = next_sched_bit(grq.prio_bitmap, ++idx); ++ if (idx >= PRIO_LIMIT) ++ return idle; ++ queue = grq.queue + idx; ++ ++ if (idx < MAX_RT_PRIO) { ++ /* We found an rt task */ ++ list_for_each_entry(p, queue, run_list) { ++ /* Make sure cpu affinity is ok */ ++ if (needs_other_cpu(p, cpu)) ++ continue; ++ edt = p; ++ goto out_take; ++ } ++ /* ++ * None of the RT tasks at this priority can run on ++ * this cpu ++ */ ++ continue; ++ } ++ ++ /* ++ * No rt tasks. Find the earliest deadline task. Now we're in ++ * O(n) territory. ++ */ ++ earliest_deadline = ~0ULL; ++ list_for_each_entry(p, queue, run_list) { ++ u64 dl; ++ ++ /* Make sure cpu affinity is ok */ ++ if (needs_other_cpu(p, cpu)) ++ continue; ++ ++ /* ++ * Soft affinity happens here by not scheduling a task ++ * with its sticky flag set that ran on a different CPU ++ * last when the CPU is scaling, or by greatly biasing ++ * against its deadline when not, based on cpu cache ++ * locality. ++ */ ++ if (task_sticky(p) && task_rq(p) != rq) { ++ if (scaling_rq(rq)) ++ continue; ++ dl = p->deadline << locality_diff(p, rq); ++ } else ++ dl = p->deadline; ++ ++ if (deadline_before(dl, earliest_deadline)) { ++ earliest_deadline = dl; ++ edt = p; ++ } ++ } ++ } while (!edt); ++ ++out_take: ++ take_task(cpu, edt); ++ return edt; ++} ++ ++ ++/* ++ * Print scheduling while atomic bug: ++ */ ++static noinline void __schedule_bug(struct task_struct *prev) ++{ ++ if (oops_in_progress) ++ return; ++ ++ printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n", ++ prev->comm, prev->pid, preempt_count()); ++ ++ debug_show_held_locks(prev); ++ print_modules(); ++ if (irqs_disabled()) ++ print_irqtrace_events(prev); ++ dump_stack(); ++ add_taint(TAINT_WARN, LOCKDEP_STILL_OK); ++} ++ ++/* ++ * Various schedule()-time debugging checks and statistics: ++ */ ++static inline void schedule_debug(struct task_struct *prev) ++{ ++ /* ++ * Test if we are atomic. Since do_exit() needs to call into ++ * schedule() atomically, we ignore that path for now. ++ * Otherwise, whine if we are scheduling when we should not be. ++ */ ++ if (unlikely(in_atomic_preempt_off() && !prev->exit_state)) ++ __schedule_bug(prev); ++ rcu_sleep_check(); ++ ++ profile_hit(SCHED_PROFILING, __builtin_return_address(0)); ++ ++ schedstat_inc(this_rq(), sched_count); ++} ++ ++/* ++ * The currently running task's information is all stored in rq local data ++ * which is only modified by the local CPU, thereby allowing the data to be ++ * changed without grabbing the grq lock. ++ */ ++static inline void set_rq_task(struct rq *rq, struct task_struct *p) ++{ ++ rq->rq_time_slice = p->time_slice; ++ rq->rq_deadline = p->deadline; ++ rq->rq_last_ran = p->last_ran = rq->clock_task; ++ rq->rq_policy = p->policy; ++ rq->rq_prio = p->prio; ++ if (p != rq->idle) ++ rq->rq_running = true; ++ else ++ rq->rq_running = false; ++} ++ ++static void reset_rq_task(struct rq *rq, struct task_struct *p) ++{ ++ rq->rq_policy = p->policy; ++ rq->rq_prio = p->prio; ++} ++ ++/* ++ * schedule() is the main scheduler function. ++ * ++ * The main means of driving the scheduler and thus entering this function are: ++ * ++ * 1. Explicit blocking: mutex, semaphore, waitqueue, etc. ++ * ++ * 2. TIF_NEED_RESCHED flag is checked on interrupt and userspace return ++ * paths. For example, see arch/x86/entry_64.S. ++ * ++ * To drive preemption between tasks, the scheduler sets the flag in timer ++ * interrupt handler scheduler_tick(). ++ * ++ * 3. Wakeups don't really cause entry into schedule(). They add a ++ * task to the run-queue and that's it. ++ * ++ * Now, if the new task added to the run-queue preempts the current ++ * task, then the wakeup sets TIF_NEED_RESCHED and schedule() gets ++ * called on the nearest possible occasion: ++ * ++ * - If the kernel is preemptible (CONFIG_PREEMPT=y): ++ * ++ * - in syscall or exception context, at the next outmost ++ * preempt_enable(). (this might be as soon as the wake_up()'s ++ * spin_unlock()!) ++ * ++ * - in IRQ context, return from interrupt-handler to ++ * preemptible context ++ * ++ * - If the kernel is not preemptible (CONFIG_PREEMPT is not set) ++ * then at the next: ++ * ++ * - cond_resched() call ++ * - explicit schedule() call ++ * - return from syscall or exception to user-space ++ * - return from interrupt-handler to user-space ++ */ ++asmlinkage void __sched schedule(void) ++{ ++ struct task_struct *prev, *next, *idle; ++ unsigned long *switch_count; ++ bool deactivate; ++ struct rq *rq; ++ int cpu; ++ ++need_resched: ++ preempt_disable(); ++ cpu = smp_processor_id(); ++ rq = cpu_rq(cpu); ++ rcu_note_context_switch(cpu); ++ prev = rq->curr; ++ ++ deactivate = false; ++ schedule_debug(prev); ++ ++ /* ++ * Make sure that signal_pending_state()->signal_pending() below ++ * can't be reordered with __set_current_state(TASK_INTERRUPTIBLE) ++ * done by the caller to avoid the race with signal_wake_up(). ++ */ ++ smp_mb__before_spinlock(); ++ grq_lock_irq(); ++ ++ switch_count = &prev->nivcsw; ++ if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) { ++ if (unlikely(signal_pending_state(prev->state, prev))) { ++ prev->state = TASK_RUNNING; ++ } else { ++ deactivate = true; ++ /* ++ * If a worker is going to sleep, notify and ++ * ask workqueue whether it wants to wake up a ++ * task to maintain concurrency. If so, wake ++ * up the task. ++ */ ++ if (prev->flags & PF_WQ_WORKER) { ++ struct task_struct *to_wakeup; ++ ++ to_wakeup = wq_worker_sleeping(prev, cpu); ++ if (to_wakeup) { ++ /* This shouldn't happen, but does */ ++ if (unlikely(to_wakeup == prev)) ++ deactivate = false; ++ else ++ try_to_wake_up_local(to_wakeup); ++ } ++ } ++ } ++ switch_count = &prev->nvcsw; ++ } ++ ++ /* ++ * If we are going to sleep and we have plugged IO queued, make ++ * sure to submit it to avoid deadlocks. ++ */ ++ if (unlikely(deactivate && blk_needs_flush_plug(prev))) { ++ grq_unlock_irq(); ++ preempt_enable_no_resched(); ++ blk_schedule_flush_plug(prev); ++ goto need_resched; ++ } ++ ++ update_clocks(rq); ++ update_cpu_clock_switch(rq, prev); ++ if (rq->clock - rq->last_tick > HALF_JIFFY_NS) ++ rq->dither = false; ++ else ++ rq->dither = true; ++ ++ clear_tsk_need_resched(prev); ++ ++ idle = rq->idle; ++ if (idle != prev) { ++ /* Update all the information stored on struct rq */ ++ prev->time_slice = rq->rq_time_slice; ++ prev->deadline = rq->rq_deadline; ++ check_deadline(prev); ++ prev->last_ran = rq->clock_task; ++ ++ /* Task changed affinity off this CPU */ ++ if (needs_other_cpu(prev, cpu)) { ++ if (!deactivate) ++ resched_suitable_idle(prev); ++ } else if (!deactivate) { ++ if (!queued_notrunning()) { ++ /* ++ * We now know prev is the only thing that is ++ * awaiting CPU so we can bypass rechecking for ++ * the earliest deadline task and just run it ++ * again. ++ */ ++ set_rq_task(rq, prev); ++ grq_unlock_irq(); ++ goto rerun_prev_unlocked; ++ } else ++ swap_sticky(rq, cpu, prev); ++ } ++ return_task(prev, deactivate); ++ } ++ ++ if (unlikely(!queued_notrunning())) { ++ /* ++ * This CPU is now truly idle as opposed to when idle is ++ * scheduled as a high priority task in its own right. ++ */ ++ next = idle; ++ schedstat_inc(rq, sched_goidle); ++ set_cpuidle_map(cpu); ++ } else { ++ next = earliest_deadline_task(rq, cpu, idle); ++ if (likely(next->prio != PRIO_LIMIT)) ++ clear_cpuidle_map(cpu); ++ else ++ set_cpuidle_map(cpu); ++ } ++ ++ if (likely(prev != next)) { ++ resched_suitable_idle(prev); ++ /* ++ * Don't stick tasks when a real time task is going to run as ++ * they may literally get stuck. ++ */ ++ if (rt_task(next)) ++ unstick_task(rq, prev); ++ set_rq_task(rq, next); ++ grq.nr_switches++; ++ prev->on_cpu = false; ++ next->on_cpu = true; ++ rq->curr = next; ++ ++*switch_count; ++ ++ context_switch(rq, prev, next); /* unlocks the grq */ ++ /* ++ * The context switch have flipped the stack from under us ++ * and restored the local variables which were saved when ++ * this task called schedule() in the past. prev == current ++ * is still correct, but it can be moved to another cpu/rq. ++ */ ++ cpu = smp_processor_id(); ++ rq = cpu_rq(cpu); ++ idle = rq->idle; ++ } else ++ grq_unlock_irq(); ++ ++rerun_prev_unlocked: ++ sched_preempt_enable_no_resched(); ++ if (unlikely(need_resched())) ++ goto need_resched; ++} ++EXPORT_SYMBOL(schedule); ++ ++#ifdef CONFIG_RCU_USER_QS ++asmlinkage void __sched schedule_user(void) ++{ ++ /* ++ * If we come here after a random call to set_need_resched(), ++ * or we have been woken up remotely but the IPI has not yet arrived, ++ * we haven't yet exited the RCU idle mode. Do it here manually until ++ * we find a better solution. ++ */ ++ user_exit(); ++ schedule(); ++ user_enter(); ++} ++#endif ++ ++/** ++ * schedule_preempt_disabled - called with preemption disabled ++ * ++ * Returns with preemption disabled. Note: preempt_count must be 1 ++ */ ++void __sched schedule_preempt_disabled(void) ++{ ++ sched_preempt_enable_no_resched(); ++ schedule(); ++ preempt_disable(); ++} ++ ++#ifdef CONFIG_PREEMPT ++/* ++ * this is the entry point to schedule() from in-kernel preemption ++ * off of preempt_enable. Kernel preemptions off return from interrupt ++ * occur there and call schedule directly. ++ */ ++asmlinkage void __sched notrace preempt_schedule(void) ++{ ++ /* ++ * If there is a non-zero preempt_count or interrupts are disabled, ++ * we do not want to preempt the current task. Just return.. ++ */ ++ if (likely(!preemptible())) ++ return; ++ ++ do { ++ add_preempt_count_notrace(PREEMPT_ACTIVE); ++ schedule(); ++ sub_preempt_count_notrace(PREEMPT_ACTIVE); ++ ++ /* ++ * Check again in case we missed a preemption opportunity ++ * between schedule and now. ++ */ ++ barrier(); ++ } while (need_resched()); ++} ++EXPORT_SYMBOL(preempt_schedule); ++ ++/* ++ * this is the entry point to schedule() from kernel preemption ++ * off of irq context. ++ * Note, that this is called and return with irqs disabled. This will ++ * protect us against recursive calling from irq. ++ */ ++asmlinkage void __sched preempt_schedule_irq(void) ++{ ++ struct thread_info *ti = current_thread_info(); ++ enum ctx_state prev_state; ++ ++ /* Catch callers which need to be fixed */ ++ BUG_ON(ti->preempt_count || !irqs_disabled()); ++ ++ prev_state = exception_enter(); ++ ++ do { ++ add_preempt_count(PREEMPT_ACTIVE); ++ local_irq_enable(); ++ schedule(); ++ local_irq_disable(); ++ sub_preempt_count(PREEMPT_ACTIVE); ++ ++ /* ++ * Check again in case we missed a preemption opportunity ++ * between schedule and now. ++ */ ++ barrier(); ++ } while (need_resched()); ++ ++ exception_exit(prev_state); ++} ++ ++#endif /* CONFIG_PREEMPT */ ++ ++int default_wake_function(wait_queue_t *curr, unsigned mode, int wake_flags, ++ void *key) ++{ ++ return try_to_wake_up(curr->private, mode, wake_flags); ++} ++EXPORT_SYMBOL(default_wake_function); ++ ++/* ++ * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just ++ * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve ++ * number) then we wake all the non-exclusive tasks and one exclusive task. ++ * ++ * There are circumstances in which we can try to wake a task which has already ++ * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns ++ * zero in this (rare) case, and we handle it by continuing to scan the queue. ++ */ ++static void __wake_up_common(wait_queue_head_t *q, unsigned int mode, ++ int nr_exclusive, int wake_flags, void *key) ++{ ++ struct list_head *tmp, *next; ++ ++ list_for_each_safe(tmp, next, &q->task_list) { ++ wait_queue_t *curr = list_entry(tmp, wait_queue_t, task_list); ++ unsigned int flags = curr->flags; ++ ++ if (curr->func(curr, mode, wake_flags, key) && ++ (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive) ++ break; ++ } ++} ++ ++/** ++ * __wake_up - wake up threads blocked on a waitqueue. ++ * @q: the waitqueue ++ * @mode: which threads ++ * @nr_exclusive: how many wake-one or wake-many threads to wake up ++ * @key: is directly passed to the wakeup function ++ * ++ * It may be assumed that this function implies a write memory barrier before ++ * changing the task state if and only if any tasks are woken up. ++ */ ++void __wake_up(wait_queue_head_t *q, unsigned int mode, ++ int nr_exclusive, void *key) ++{ ++ unsigned long flags; ++ ++ spin_lock_irqsave(&q->lock, flags); ++ __wake_up_common(q, mode, nr_exclusive, 0, key); ++ spin_unlock_irqrestore(&q->lock, flags); ++} ++EXPORT_SYMBOL(__wake_up); ++ ++/* ++ * Same as __wake_up but called with the spinlock in wait_queue_head_t held. ++ */ ++void __wake_up_locked(wait_queue_head_t *q, unsigned int mode, int nr) ++{ ++ __wake_up_common(q, mode, nr, 0, NULL); ++} ++EXPORT_SYMBOL_GPL(__wake_up_locked); ++ ++void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key) ++{ ++ __wake_up_common(q, mode, 1, 0, key); ++} ++EXPORT_SYMBOL_GPL(__wake_up_locked_key); ++ ++/** ++ * __wake_up_sync_key - wake up threads blocked on a waitqueue. ++ * @q: the waitqueue ++ * @mode: which threads ++ * @nr_exclusive: how many wake-one or wake-many threads to wake up ++ * @key: opaque value to be passed to wakeup targets ++ * ++ * The sync wakeup differs that the waker knows that it will schedule ++ * away soon, so while the target thread will be woken up, it will not ++ * be migrated to another CPU - ie. the two threads are 'synchronised' ++ * with each other. This can prevent needless bouncing between CPUs. ++ * ++ * On UP it can prevent extra preemption. ++ * ++ * It may be assumed that this function implies a write memory barrier before ++ * changing the task state if and only if any tasks are woken up. ++ */ ++void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode, ++ int nr_exclusive, void *key) ++{ ++ unsigned long flags; ++ int wake_flags = WF_SYNC; ++ ++ if (unlikely(!q)) ++ return; ++ ++ if (unlikely(nr_exclusive != 1)) ++ wake_flags = 0; ++ ++ spin_lock_irqsave(&q->lock, flags); ++ __wake_up_common(q, mode, nr_exclusive, wake_flags, key); ++ spin_unlock_irqrestore(&q->lock, flags); ++} ++EXPORT_SYMBOL_GPL(__wake_up_sync_key); ++ ++/** ++ * __wake_up_sync - wake up threads blocked on a waitqueue. ++ * @q: the waitqueue ++ * @mode: which threads ++ * @nr_exclusive: how many wake-one or wake-many threads to wake up ++ * ++ * The sync wakeup differs that the waker knows that it will schedule ++ * away soon, so while the target thread will be woken up, it will not ++ * be migrated to another CPU - ie. the two threads are 'synchronised' ++ * with each other. This can prevent needless bouncing between CPUs. ++ * ++ * On UP it can prevent extra preemption. ++ */ ++void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive) ++{ ++ unsigned long flags; ++ int sync = 1; ++ ++ if (unlikely(!q)) ++ return; ++ ++ if (unlikely(!nr_exclusive)) ++ sync = 0; ++ ++ spin_lock_irqsave(&q->lock, flags); ++ __wake_up_common(q, mode, nr_exclusive, sync, NULL); ++ spin_unlock_irqrestore(&q->lock, flags); ++} ++EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */ ++ ++/** ++ * complete: - signals a single thread waiting on this completion ++ * @x: holds the state of this particular completion ++ * ++ * This will wake up a single thread waiting on this completion. Threads will be ++ * awakened in the same order in which they were queued. ++ * ++ * See also complete_all(), wait_for_completion() and related routines. ++ * ++ * It may be assumed that this function implies a write memory barrier before ++ * changing the task state if and only if any tasks are woken up. ++ */ ++void complete(struct completion *x) ++{ ++ unsigned long flags; ++ ++ spin_lock_irqsave(&x->wait.lock, flags); ++ x->done++; ++ __wake_up_common(&x->wait, TASK_NORMAL, 1, 0, NULL); ++ spin_unlock_irqrestore(&x->wait.lock, flags); ++} ++EXPORT_SYMBOL(complete); ++ ++/** ++ * complete_all: - signals all threads waiting on this completion ++ * @x: holds the state of this particular completion ++ * ++ * This will wake up all threads waiting on this particular completion event. ++ * ++ * It may be assumed that this function implies a write memory barrier before ++ * changing the task state if and only if any tasks are woken up. ++ */ ++void complete_all(struct completion *x) ++{ ++ unsigned long flags; ++ ++ spin_lock_irqsave(&x->wait.lock, flags); ++ x->done += UINT_MAX/2; ++ __wake_up_common(&x->wait, TASK_NORMAL, 0, 0, NULL); ++ spin_unlock_irqrestore(&x->wait.lock, flags); ++} ++EXPORT_SYMBOL(complete_all); ++ ++static inline long __sched ++do_wait_for_common(struct completion *x, ++ long (*action)(long), long timeout, int state) ++{ ++ if (!x->done) { ++ DECLARE_WAITQUEUE(wait, current); ++ ++ __add_wait_queue_tail_exclusive(&x->wait, &wait); ++ do { ++ if (signal_pending_state(state, current)) { ++ timeout = -ERESTARTSYS; ++ break; ++ } ++ __set_current_state(state); ++ spin_unlock_irq(&x->wait.lock); ++ timeout = action(timeout); ++ spin_lock_irq(&x->wait.lock); ++ } while (!x->done && timeout); ++ __remove_wait_queue(&x->wait, &wait); ++ if (!x->done) ++ return timeout; ++ } ++ x->done--; ++ return timeout ?: 1; ++} ++ ++static inline long __sched ++__wait_for_common(struct completion *x, ++ long (*action)(long), long timeout, int state) ++{ ++ might_sleep(); ++ ++ spin_lock_irq(&x->wait.lock); ++ timeout = do_wait_for_common(x, action, timeout, state); ++ spin_unlock_irq(&x->wait.lock); ++ return timeout; ++} ++ ++static long __sched ++wait_for_common(struct completion *x, long timeout, int state) ++{ ++ return __wait_for_common(x, schedule_timeout, timeout, state); ++} ++ ++static long __sched ++wait_for_common_io(struct completion *x, long timeout, int state) ++{ ++ return __wait_for_common(x, io_schedule_timeout, timeout, state); ++} ++ ++/** ++ * wait_for_completion: - waits for completion of a task ++ * @x: holds the state of this particular completion ++ * ++ * This waits to be signaled for completion of a specific task. It is NOT ++ * interruptible and there is no timeout. ++ * ++ * See also similar routines (i.e. wait_for_completion_timeout()) with timeout ++ * and interrupt capability. Also see complete(). ++ */ ++void __sched wait_for_completion(struct completion *x) ++{ ++ wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE); ++} ++EXPORT_SYMBOL(wait_for_completion); ++ ++/** ++ * wait_for_completion_timeout: - waits for completion of a task (w/timeout) ++ * @x: holds the state of this particular completion ++ * @timeout: timeout value in jiffies ++ * ++ * This waits for either a completion of a specific task to be signaled or for a ++ * specified timeout to expire. The timeout is in jiffies. It is not ++ * interruptible. ++ * ++ * Return: 0 if timed out, and positive (at least 1, or number of jiffies left ++ * till timeout) if completed. ++ */ ++unsigned long __sched ++wait_for_completion_timeout(struct completion *x, unsigned long timeout) ++{ ++ return wait_for_common(x, timeout, TASK_UNINTERRUPTIBLE); ++} ++EXPORT_SYMBOL(wait_for_completion_timeout); ++ ++ /** ++ * wait_for_completion_io: - waits for completion of a task ++ * @x: holds the state of this particular completion ++ * ++ * This waits to be signaled for completion of a specific task. It is NOT ++ * interruptible and there is no timeout. The caller is accounted as waiting ++ * for IO. ++ */ ++void __sched wait_for_completion_io(struct completion *x) ++{ ++ wait_for_common_io(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE); ++} ++EXPORT_SYMBOL(wait_for_completion_io); ++ ++/** ++ * wait_for_completion_io_timeout: - waits for completion of a task (w/timeout) ++ * @x: holds the state of this particular completion ++ * @timeout: timeout value in jiffies ++ * ++ * This waits for either a completion of a specific task to be signaled or for a ++ * specified timeout to expire. The timeout is in jiffies. It is not ++ * interruptible. The caller is accounted as waiting for IO. ++ * ++ * Return: 0 if timed out, and positive (at least 1, or number of jiffies left ++ * till timeout) if completed. ++ */ ++unsigned long __sched ++wait_for_completion_io_timeout(struct completion *x, unsigned long timeout) ++{ ++ return wait_for_common_io(x, timeout, TASK_UNINTERRUPTIBLE); ++} ++EXPORT_SYMBOL(wait_for_completion_io_timeout); ++ ++/** ++ * wait_for_completion_interruptible: - waits for completion of a task (w/intr) ++ * @x: holds the state of this particular completion ++ * ++ * This waits for completion of a specific task to be signaled. It is ++ * interruptible. ++ * ++ * Return: -ERESTARTSYS if interrupted, 0 if completed. ++ */ ++int __sched wait_for_completion_interruptible(struct completion *x) ++{ ++ long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_INTERRUPTIBLE); ++ if (t == -ERESTARTSYS) ++ return t; ++ return 0; ++} ++EXPORT_SYMBOL(wait_for_completion_interruptible); ++ ++/** ++ * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr)) ++ * @x: holds the state of this particular completion ++ * @timeout: timeout value in jiffies ++ * ++ * This waits for either a completion of a specific task to be signaled or for a ++ * specified timeout to expire. It is interruptible. The timeout is in jiffies. ++ * ++ * Return: -ERESTARTSYS if interrupted, 0 if timed out, positive (at least 1, ++ * or number of jiffies left till timeout) if completed. ++ */ ++long __sched ++wait_for_completion_interruptible_timeout(struct completion *x, ++ unsigned long timeout) ++{ ++ return wait_for_common(x, timeout, TASK_INTERRUPTIBLE); ++} ++EXPORT_SYMBOL(wait_for_completion_interruptible_timeout); ++ ++/** ++ * wait_for_completion_killable: - waits for completion of a task (killable) ++ * @x: holds the state of this particular completion ++ * ++ * This waits to be signaled for completion of a specific task. It can be ++ * interrupted by a kill signal. ++ * ++ * Return: -ERESTARTSYS if interrupted, 0 if completed. ++ */ ++int __sched wait_for_completion_killable(struct completion *x) ++{ ++ long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_KILLABLE); ++ if (t == -ERESTARTSYS) ++ return t; ++ return 0; ++} ++EXPORT_SYMBOL(wait_for_completion_killable); ++ ++/** ++ * wait_for_completion_killable_timeout: - waits for completion of a task (w/(to,killable)) ++ * @x: holds the state of this particular completion ++ * @timeout: timeout value in jiffies ++ * ++ * This waits for either a completion of a specific task to be ++ * signaled or for a specified timeout to expire. It can be ++ * interrupted by a kill signal. The timeout is in jiffies. ++ * ++ * Return: -ERESTARTSYS if interrupted, 0 if timed out, positive (at least 1, ++ * or number of jiffies left till timeout) if completed. ++ */ ++long __sched ++wait_for_completion_killable_timeout(struct completion *x, ++ unsigned long timeout) ++{ ++ return wait_for_common(x, timeout, TASK_KILLABLE); ++} ++EXPORT_SYMBOL(wait_for_completion_killable_timeout); ++ ++/** ++ * try_wait_for_completion - try to decrement a completion without blocking ++ * @x: completion structure ++ * ++ * Return: 0 if a decrement cannot be done without blocking ++ * 1 if a decrement succeeded. ++ * ++ * If a completion is being used as a counting completion, ++ * attempt to decrement the counter without blocking. This ++ * enables us to avoid waiting if the resource the completion ++ * is protecting is not available. ++ */ ++bool try_wait_for_completion(struct completion *x) ++{ ++ unsigned long flags; ++ int ret = 1; ++ ++ spin_lock_irqsave(&x->wait.lock, flags); ++ if (!x->done) ++ ret = 0; ++ else ++ x->done--; ++ spin_unlock_irqrestore(&x->wait.lock, flags); ++ return ret; ++} ++EXPORT_SYMBOL(try_wait_for_completion); ++ ++/** ++ * completion_done - Test to see if a completion has any waiters ++ * @x: completion structure ++ * ++ * Return: 0 if there are waiters (wait_for_completion() in progress) ++ * 1 if there are no waiters. ++ * ++ */ ++bool completion_done(struct completion *x) ++{ ++ unsigned long flags; ++ int ret = 1; ++ ++ spin_lock_irqsave(&x->wait.lock, flags); ++ if (!x->done) ++ ret = 0; ++ spin_unlock_irqrestore(&x->wait.lock, flags); ++ return ret; ++} ++EXPORT_SYMBOL(completion_done); ++ ++static long __sched ++sleep_on_common(wait_queue_head_t *q, int state, long timeout) ++{ ++ unsigned long flags; ++ wait_queue_t wait; ++ ++ init_waitqueue_entry(&wait, current); ++ ++ __set_current_state(state); ++ ++ spin_lock_irqsave(&q->lock, flags); ++ __add_wait_queue(q, &wait); ++ spin_unlock(&q->lock); ++ timeout = schedule_timeout(timeout); ++ spin_lock_irq(&q->lock); ++ __remove_wait_queue(q, &wait); ++ spin_unlock_irqrestore(&q->lock, flags); ++ ++ return timeout; ++} ++ ++void __sched interruptible_sleep_on(wait_queue_head_t *q) ++{ ++ sleep_on_common(q, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); ++} ++EXPORT_SYMBOL(interruptible_sleep_on); ++ ++long __sched ++interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout) ++{ ++ return sleep_on_common(q, TASK_INTERRUPTIBLE, timeout); ++} ++EXPORT_SYMBOL(interruptible_sleep_on_timeout); ++ ++void __sched sleep_on(wait_queue_head_t *q) ++{ ++ sleep_on_common(q, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); ++} ++EXPORT_SYMBOL(sleep_on); ++ ++long __sched sleep_on_timeout(wait_queue_head_t *q, long timeout) ++{ ++ return sleep_on_common(q, TASK_UNINTERRUPTIBLE, timeout); ++} ++EXPORT_SYMBOL(sleep_on_timeout); ++ ++#ifdef CONFIG_RT_MUTEXES ++ ++/* ++ * rt_mutex_setprio - set the current priority of a task ++ * @p: task ++ * @prio: prio value (kernel-internal form) ++ * ++ * This function changes the 'effective' priority of a task. It does ++ * not touch ->normal_prio like __setscheduler(). ++ * ++ * Used by the rt_mutex code to implement priority inheritance logic. ++ */ ++void rt_mutex_setprio(struct task_struct *p, int prio) ++{ ++ unsigned long flags; ++ int queued, oldprio; ++ struct rq *rq; ++ ++ BUG_ON(prio < 0 || prio > MAX_PRIO); ++ ++ rq = task_grq_lock(p, &flags); ++ ++ /* ++ * Idle task boosting is a nono in general. There is one ++ * exception, when PREEMPT_RT and NOHZ is active: ++ * ++ * The idle task calls get_next_timer_interrupt() and holds ++ * the timer wheel base->lock on the CPU and another CPU wants ++ * to access the timer (probably to cancel it). We can safely ++ * ignore the boosting request, as the idle CPU runs this code ++ * with interrupts disabled and will complete the lock ++ * protected section without being interrupted. So there is no ++ * real need to boost. ++ */ ++ if (unlikely(p == rq->idle)) { ++ WARN_ON(p != rq->curr); ++ WARN_ON(p->pi_blocked_on); ++ goto out_unlock; ++ } ++ ++ trace_sched_pi_setprio(p, prio); ++ oldprio = p->prio; ++ queued = task_queued(p); ++ if (queued) ++ dequeue_task(p); ++ p->prio = prio; ++ if (task_running(p) && prio > oldprio) ++ resched_task(p); ++ if (queued) { ++ enqueue_task(p); ++ try_preempt(p, rq); ++ } ++ ++out_unlock: ++ task_grq_unlock(&flags); ++} ++ ++#endif ++ ++/* ++ * Adjust the deadline for when the priority is to change, before it's ++ * changed. ++ */ ++static inline void adjust_deadline(struct task_struct *p, int new_prio) ++{ ++ p->deadline += static_deadline_diff(new_prio) - task_deadline_diff(p); ++} ++ ++void set_user_nice(struct task_struct *p, long nice) ++{ ++ int queued, new_static, old_static; ++ unsigned long flags; ++ struct rq *rq; ++ ++ if (TASK_NICE(p) == nice || nice < -20 || nice > 19) ++ return; ++ new_static = NICE_TO_PRIO(nice); ++ /* ++ * We have to be careful, if called from sys_setpriority(), ++ * the task might be in the middle of scheduling on another CPU. ++ */ ++ rq = time_task_grq_lock(p, &flags); ++ /* ++ * The RT priorities are set via sched_setscheduler(), but we still ++ * allow the 'normal' nice value to be set - but as expected ++ * it wont have any effect on scheduling until the task is ++ * not SCHED_NORMAL/SCHED_BATCH: ++ */ ++ if (has_rt_policy(p)) { ++ p->static_prio = new_static; ++ goto out_unlock; ++ } ++ queued = task_queued(p); ++ if (queued) ++ dequeue_task(p); ++ ++ adjust_deadline(p, new_static); ++ old_static = p->static_prio; ++ p->static_prio = new_static; ++ p->prio = effective_prio(p); ++ ++ if (queued) { ++ enqueue_task(p); ++ if (new_static < old_static) ++ try_preempt(p, rq); ++ } else if (task_running(p)) { ++ reset_rq_task(rq, p); ++ if (old_static < new_static) ++ resched_task(p); ++ } ++out_unlock: ++ task_grq_unlock(&flags); ++} ++EXPORT_SYMBOL(set_user_nice); ++ ++/* ++ * can_nice - check if a task can reduce its nice value ++ * @p: task ++ * @nice: nice value ++ */ ++int can_nice(const struct task_struct *p, const int nice) ++{ ++ /* convert nice value [19,-20] to rlimit style value [1,40] */ ++ int nice_rlim = 20 - nice; ++ ++ return (nice_rlim <= task_rlimit(p, RLIMIT_NICE) || ++ capable(CAP_SYS_NICE)); ++} ++ ++#ifdef __ARCH_WANT_SYS_NICE ++ ++/* ++ * sys_nice - change the priority of the current process. ++ * @increment: priority increment ++ * ++ * sys_setpriority is a more generic, but much slower function that ++ * does similar things. ++ */ ++SYSCALL_DEFINE1(nice, int, increment) ++{ ++ long nice, retval; ++ ++ /* ++ * Setpriority might change our priority at the same moment. ++ * We don't have to worry. Conceptually one call occurs first ++ * and we have a single winner. ++ */ ++ if (increment < -40) ++ increment = -40; ++ if (increment > 40) ++ increment = 40; ++ ++ nice = TASK_NICE(current) + increment; ++ if (nice < -20) ++ nice = -20; ++ if (nice > 19) ++ nice = 19; ++ ++ if (increment < 0 && !can_nice(current, nice)) ++ return -EPERM; ++ ++ retval = security_task_setnice(current, nice); ++ if (retval) ++ return retval; ++ ++ set_user_nice(current, nice); ++ return 0; ++} ++ ++#endif ++ ++/** ++ * task_prio - return the priority value of a given task. ++ * @p: the task in question. ++ * ++ * Return: The priority value as seen by users in /proc. ++ * RT tasks are offset by -100. Normal tasks are centered around 1, value goes ++ * from 0 (SCHED_ISO) up to 82 (nice +19 SCHED_IDLEPRIO). ++ */ ++int task_prio(const struct task_struct *p) ++{ ++ int delta, prio = p->prio - MAX_RT_PRIO; ++ ++ /* rt tasks and iso tasks */ ++ if (prio <= 0) ++ goto out; ++ ++ /* Convert to ms to avoid overflows */ ++ delta = NS_TO_MS(p->deadline - grq.niffies); ++ delta = delta * 40 / ms_longest_deadline_diff(); ++ if (delta > 0 && delta <= 80) ++ prio += delta; ++ if (idleprio_task(p)) ++ prio += 40; ++out: ++ return prio; ++} ++ ++/** ++ * task_nice - return the nice value of a given task. ++ * @p: the task in question. ++ * ++ * Return: The nice value [ -20 ... 0 ... 19 ]. ++ */ ++int task_nice(const struct task_struct *p) ++{ ++ return TASK_NICE(p); ++} ++EXPORT_SYMBOL_GPL(task_nice); ++ ++/** ++ * idle_cpu - is a given cpu idle currently? ++ * @cpu: the processor in question. ++ * ++ * Return: 1 if the CPU is currently idle. 0 otherwise. ++ */ ++int idle_cpu(int cpu) ++{ ++#ifdef CONFIG_SMP ++ struct rq *rq = cpu_rq(cpu); ++ ++ if (!llist_empty(&rq->wake_list)) ++ return 0; ++#endif ++ return cpu_curr(cpu) == cpu_rq(cpu)->idle; ++} ++ ++/** ++ * idle_task - return the idle task for a given cpu. ++ * @cpu: the processor in question. ++ * ++ * Return: The idle task for the cpu @cpu. ++ */ ++struct task_struct *idle_task(int cpu) ++{ ++ return cpu_rq(cpu)->idle; ++} ++ ++/** ++ * find_process_by_pid - find a process with a matching PID value. ++ * @pid: the pid in question. ++ * ++ * The task of @pid, if found. %NULL otherwise. ++ */ ++static inline struct task_struct *find_process_by_pid(pid_t pid) ++{ ++ return pid ? find_task_by_vpid(pid) : current; ++} ++ ++/* Actually do priority change: must hold grq lock. */ ++static void ++__setscheduler(struct task_struct *p, struct rq *rq, int policy, int prio) ++{ ++ int oldrtprio, oldprio; ++ ++ p->policy = policy; ++ oldrtprio = p->rt_priority; ++ p->rt_priority = prio; ++ p->normal_prio = normal_prio(p); ++ oldprio = p->prio; ++ /* we are holding p->pi_lock already */ ++ p->prio = rt_mutex_getprio(p); ++ if (task_running(p)) { ++ reset_rq_task(rq, p); ++ /* Resched only if we might now be preempted */ ++ if (p->prio > oldprio || p->rt_priority > oldrtprio) ++ resched_task(p); ++ } ++} ++ ++/* ++ * check the target process has a UID that matches the current process's ++ */ ++static bool check_same_owner(struct task_struct *p) ++{ ++ const struct cred *cred = current_cred(), *pcred; ++ bool match; ++ ++ rcu_read_lock(); ++ pcred = __task_cred(p); ++ match = (uid_eq(cred->euid, pcred->euid) || ++ uid_eq(cred->euid, pcred->uid)); ++ rcu_read_unlock(); ++ return match; ++} ++ ++static int __sched_setscheduler(struct task_struct *p, int policy, ++ const struct sched_param *param, bool user) ++{ ++ struct sched_param zero_param = { .sched_priority = 0 }; ++ int queued, retval, oldpolicy = -1; ++ unsigned long flags, rlim_rtprio = 0; ++ int reset_on_fork; ++ struct rq *rq; ++ ++ /* may grab non-irq protected spin_locks */ ++ BUG_ON(in_interrupt()); ++ ++ if (is_rt_policy(policy) && !capable(CAP_SYS_NICE)) { ++ unsigned long lflags; ++ ++ if (!lock_task_sighand(p, &lflags)) ++ return -ESRCH; ++ rlim_rtprio = task_rlimit(p, RLIMIT_RTPRIO); ++ unlock_task_sighand(p, &lflags); ++ if (rlim_rtprio) ++ goto recheck; ++ /* ++ * If the caller requested an RT policy without having the ++ * necessary rights, we downgrade the policy to SCHED_ISO. ++ * We also set the parameter to zero to pass the checks. ++ */ ++ policy = SCHED_ISO; ++ param = &zero_param; ++ } ++recheck: ++ /* double check policy once rq lock held */ ++ if (policy < 0) { ++ reset_on_fork = p->sched_reset_on_fork; ++ policy = oldpolicy = p->policy; ++ } else { ++ reset_on_fork = !!(policy & SCHED_RESET_ON_FORK); ++ policy &= ~SCHED_RESET_ON_FORK; ++ ++ if (!SCHED_RANGE(policy)) ++ return -EINVAL; ++ } ++ ++ /* ++ * Valid priorities for SCHED_FIFO and SCHED_RR are ++ * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL and ++ * SCHED_BATCH is 0. ++ */ ++ if (param->sched_priority < 0 || ++ (p->mm && param->sched_priority > MAX_USER_RT_PRIO - 1) || ++ (!p->mm && param->sched_priority > MAX_RT_PRIO - 1)) ++ return -EINVAL; ++ if (is_rt_policy(policy) != (param->sched_priority != 0)) ++ return -EINVAL; ++ ++ /* ++ * Allow unprivileged RT tasks to decrease priority: ++ */ ++ if (user && !capable(CAP_SYS_NICE)) { ++ if (is_rt_policy(policy)) { ++ unsigned long rlim_rtprio = ++ task_rlimit(p, RLIMIT_RTPRIO); ++ ++ /* can't set/change the rt policy */ ++ if (policy != p->policy && !rlim_rtprio) ++ return -EPERM; ++ ++ /* can't increase priority */ ++ if (param->sched_priority > p->rt_priority && ++ param->sched_priority > rlim_rtprio) ++ return -EPERM; ++ } else { ++ switch (p->policy) { ++ /* ++ * Can only downgrade policies but not back to ++ * SCHED_NORMAL ++ */ ++ case SCHED_ISO: ++ if (policy == SCHED_ISO) ++ goto out; ++ if (policy == SCHED_NORMAL) ++ return -EPERM; ++ break; ++ case SCHED_BATCH: ++ if (policy == SCHED_BATCH) ++ goto out; ++ if (policy != SCHED_IDLEPRIO) ++ return -EPERM; ++ break; ++ case SCHED_IDLEPRIO: ++ if (policy == SCHED_IDLEPRIO) ++ goto out; ++ return -EPERM; ++ default: ++ break; ++ } ++ } ++ ++ /* can't change other user's priorities */ ++ if (!check_same_owner(p)) ++ return -EPERM; ++ ++ /* Normal users shall not reset the sched_reset_on_fork flag */ ++ if (p->sched_reset_on_fork && !reset_on_fork) ++ return -EPERM; ++ } ++ ++ if (user) { ++ retval = security_task_setscheduler(p); ++ if (retval) ++ return retval; ++ } ++ ++ /* ++ * make sure no PI-waiters arrive (or leave) while we are ++ * changing the priority of the task: ++ */ ++ raw_spin_lock_irqsave(&p->pi_lock, flags); ++ /* ++ * To be able to change p->policy safely, the grunqueue lock must be ++ * held. ++ */ ++ rq = __task_grq_lock(p); ++ ++ /* ++ * Changing the policy of the stop threads its a very bad idea ++ */ ++ if (p == rq->stop) { ++ __task_grq_unlock(); ++ raw_spin_unlock_irqrestore(&p->pi_lock, flags); ++ return -EINVAL; ++ } ++ ++ /* ++ * If not changing anything there's no need to proceed further: ++ */ ++ if (unlikely(policy == p->policy && (!is_rt_policy(policy) || ++ param->sched_priority == p->rt_priority))) { ++ ++ __task_grq_unlock(); ++ raw_spin_unlock_irqrestore(&p->pi_lock, flags); ++ return 0; ++ } ++ ++ /* recheck policy now with rq lock held */ ++ if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) { ++ policy = oldpolicy = -1; ++ __task_grq_unlock(); ++ raw_spin_unlock_irqrestore(&p->pi_lock, flags); ++ goto recheck; ++ } ++ update_clocks(rq); ++ p->sched_reset_on_fork = reset_on_fork; ++ ++ queued = task_queued(p); ++ if (queued) ++ dequeue_task(p); ++ __setscheduler(p, rq, policy, param->sched_priority); ++ if (queued) { ++ enqueue_task(p); ++ try_preempt(p, rq); ++ } ++ __task_grq_unlock(); ++ raw_spin_unlock_irqrestore(&p->pi_lock, flags); ++ ++ rt_mutex_adjust_pi(p); ++out: ++ return 0; ++} ++ ++/** ++ * sched_setscheduler - change the scheduling policy and/or RT priority of a thread. ++ * @p: the task in question. ++ * @policy: new policy. ++ * @param: structure containing the new RT priority. ++ * ++ * Return: 0 on success. An error code otherwise. ++ * ++ * NOTE that the task may be already dead. ++ */ ++int sched_setscheduler(struct task_struct *p, int policy, ++ const struct sched_param *param) ++{ ++ return __sched_setscheduler(p, policy, param, true); ++} ++ ++EXPORT_SYMBOL_GPL(sched_setscheduler); ++ ++/** ++ * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace. ++ * @p: the task in question. ++ * @policy: new policy. ++ * @param: structure containing the new RT priority. ++ * ++ * Just like sched_setscheduler, only don't bother checking if the ++ * current context has permission. For example, this is needed in ++ * stop_machine(): we create temporary high priority worker threads, ++ * but our caller might not have that capability. ++ * ++ * Return: 0 on success. An error code otherwise. ++ */ ++int sched_setscheduler_nocheck(struct task_struct *p, int policy, ++ const struct sched_param *param) ++{ ++ return __sched_setscheduler(p, policy, param, false); ++} ++ ++static int ++do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param) ++{ ++ struct sched_param lparam; ++ struct task_struct *p; ++ int retval; ++ ++ if (!param || pid < 0) ++ return -EINVAL; ++ if (copy_from_user(&lparam, param, sizeof(struct sched_param))) ++ return -EFAULT; ++ ++ rcu_read_lock(); ++ retval = -ESRCH; ++ p = find_process_by_pid(pid); ++ if (p != NULL) ++ retval = sched_setscheduler(p, policy, &lparam); ++ rcu_read_unlock(); ++ ++ return retval; ++} ++ ++/** ++ * sys_sched_setscheduler - set/change the scheduler policy and RT priority ++ * @pid: the pid in question. ++ * @policy: new policy. ++ * ++ * Return: 0 on success. An error code otherwise. ++ * @param: structure containing the new RT priority. ++ */ ++asmlinkage long sys_sched_setscheduler(pid_t pid, int policy, ++ struct sched_param __user *param) ++{ ++ /* negative values for policy are not valid */ ++ if (policy < 0) ++ return -EINVAL; ++ ++ return do_sched_setscheduler(pid, policy, param); ++} ++ ++/** ++ * sys_sched_setparam - set/change the RT priority of a thread ++ * @pid: the pid in question. ++ * @param: structure containing the new RT priority. ++ * ++ * Return: 0 on success. An error code otherwise. ++ */ ++SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param) ++{ ++ return do_sched_setscheduler(pid, -1, param); ++} ++ ++/** ++ * sys_sched_getscheduler - get the policy (scheduling class) of a thread ++ * @pid: the pid in question. ++ * ++ * Return: On success, the policy of the thread. Otherwise, a negative error ++ * code. ++ */ ++SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid) ++{ ++ struct task_struct *p; ++ int retval = -EINVAL; ++ ++ if (pid < 0) ++ goto out_nounlock; ++ ++ retval = -ESRCH; ++ rcu_read_lock(); ++ p = find_process_by_pid(pid); ++ if (p) { ++ retval = security_task_getscheduler(p); ++ if (!retval) ++ retval = p->policy; ++ } ++ rcu_read_unlock(); ++ ++out_nounlock: ++ return retval; ++} ++ ++/** ++ * sys_sched_getscheduler - get the RT priority of a thread ++ * @pid: the pid in question. ++ * @param: structure containing the RT priority. ++ * ++ * Return: On success, 0 and the RT priority is in @param. Otherwise, an error ++ * code. ++ */ ++SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param) ++{ ++ struct sched_param lp; ++ struct task_struct *p; ++ int retval = -EINVAL; ++ ++ if (!param || pid < 0) ++ goto out_nounlock; ++ ++ rcu_read_lock(); ++ p = find_process_by_pid(pid); ++ retval = -ESRCH; ++ if (!p) ++ goto out_unlock; ++ ++ retval = security_task_getscheduler(p); ++ if (retval) ++ goto out_unlock; ++ ++ lp.sched_priority = p->rt_priority; ++ rcu_read_unlock(); ++ ++ /* ++ * This one might sleep, we cannot do it with a spinlock held ... ++ */ ++ retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0; ++ ++out_nounlock: ++ return retval; ++ ++out_unlock: ++ rcu_read_unlock(); ++ return retval; ++} ++ ++long sched_setaffinity(pid_t pid, const struct cpumask *in_mask) ++{ ++ cpumask_var_t cpus_allowed, new_mask; ++ struct task_struct *p; ++ int retval; ++ ++ get_online_cpus(); ++ rcu_read_lock(); ++ ++ p = find_process_by_pid(pid); ++ if (!p) { ++ rcu_read_unlock(); ++ put_online_cpus(); ++ return -ESRCH; ++ } ++ ++ /* Prevent p going away */ ++ get_task_struct(p); ++ rcu_read_unlock(); ++ ++ if (p->flags & PF_NO_SETAFFINITY) { ++ retval = -EINVAL; ++ goto out_put_task; ++ } ++ if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) { ++ retval = -ENOMEM; ++ goto out_put_task; ++ } ++ if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) { ++ retval = -ENOMEM; ++ goto out_free_cpus_allowed; ++ } ++ retval = -EPERM; ++ if (!check_same_owner(p)) { ++ rcu_read_lock(); ++ if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) { ++ rcu_read_unlock(); ++ goto out_unlock; ++ } ++ rcu_read_unlock(); ++ } ++ ++ retval = security_task_setscheduler(p); ++ if (retval) ++ goto out_unlock; ++ ++ cpuset_cpus_allowed(p, cpus_allowed); ++ cpumask_and(new_mask, in_mask, cpus_allowed); ++again: ++ retval = set_cpus_allowed_ptr(p, new_mask); ++ ++ if (!retval) { ++ cpuset_cpus_allowed(p, cpus_allowed); ++ if (!cpumask_subset(new_mask, cpus_allowed)) { ++ /* ++ * We must have raced with a concurrent cpuset ++ * update. Just reset the cpus_allowed to the ++ * cpuset's cpus_allowed ++ */ ++ cpumask_copy(new_mask, cpus_allowed); ++ goto again; ++ } ++ } ++out_unlock: ++ free_cpumask_var(new_mask); ++out_free_cpus_allowed: ++ free_cpumask_var(cpus_allowed); ++out_put_task: ++ put_task_struct(p); ++ put_online_cpus(); ++ return retval; ++} ++ ++static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len, ++ cpumask_t *new_mask) ++{ ++ if (len < sizeof(cpumask_t)) { ++ memset(new_mask, 0, sizeof(cpumask_t)); ++ } else if (len > sizeof(cpumask_t)) { ++ len = sizeof(cpumask_t); ++ } ++ return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0; ++} ++ ++ ++/** ++ * sys_sched_setaffinity - set the cpu affinity of a process ++ * @pid: pid of the process ++ * @len: length in bytes of the bitmask pointed to by user_mask_ptr ++ * @user_mask_ptr: user-space pointer to the new cpu mask ++ * ++ * Return: 0 on success. An error code otherwise. ++ */ ++SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len, ++ unsigned long __user *, user_mask_ptr) ++{ ++ cpumask_var_t new_mask; ++ int retval; ++ ++ if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) ++ return -ENOMEM; ++ ++ retval = get_user_cpu_mask(user_mask_ptr, len, new_mask); ++ if (retval == 0) ++ retval = sched_setaffinity(pid, new_mask); ++ free_cpumask_var(new_mask); ++ return retval; ++} ++ ++long sched_getaffinity(pid_t pid, cpumask_t *mask) ++{ ++ struct task_struct *p; ++ unsigned long flags; ++ int retval; ++ ++ get_online_cpus(); ++ rcu_read_lock(); ++ ++ retval = -ESRCH; ++ p = find_process_by_pid(pid); ++ if (!p) ++ goto out_unlock; ++ ++ retval = security_task_getscheduler(p); ++ if (retval) ++ goto out_unlock; ++ ++ grq_lock_irqsave(&flags); ++ cpumask_and(mask, tsk_cpus_allowed(p), cpu_online_mask); ++ grq_unlock_irqrestore(&flags); ++ ++out_unlock: ++ rcu_read_unlock(); ++ put_online_cpus(); ++ ++ return retval; ++} ++ ++/** ++ * sys_sched_getaffinity - get the cpu affinity of a process ++ * @pid: pid of the process ++ * @len: length in bytes of the bitmask pointed to by user_mask_ptr ++ * @user_mask_ptr: user-space pointer to hold the current cpu mask ++ * ++ * Return: 0 on success. An error code otherwise. ++ */ ++SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len, ++ unsigned long __user *, user_mask_ptr) ++{ ++ int ret; ++ cpumask_var_t mask; ++ ++ if ((len * BITS_PER_BYTE) < nr_cpu_ids) ++ return -EINVAL; ++ if (len & (sizeof(unsigned long)-1)) ++ return -EINVAL; ++ ++ if (!alloc_cpumask_var(&mask, GFP_KERNEL)) ++ return -ENOMEM; ++ ++ ret = sched_getaffinity(pid, mask); ++ if (ret == 0) { ++ size_t retlen = min_t(size_t, len, cpumask_size()); ++ ++ if (copy_to_user(user_mask_ptr, mask, retlen)) ++ ret = -EFAULT; ++ else ++ ret = retlen; ++ } ++ free_cpumask_var(mask); ++ ++ return ret; ++} ++ ++/** ++ * sys_sched_yield - yield the current processor to other threads. ++ * ++ * This function yields the current CPU to other tasks. It does this by ++ * scheduling away the current task. If it still has the earliest deadline ++ * it will be scheduled again as the next task. ++ * ++ * Return: 0. ++ */ ++SYSCALL_DEFINE0(sched_yield) ++{ ++ struct task_struct *p; ++ ++ p = current; ++ grq_lock_irq(); ++ schedstat_inc(task_rq(p), yld_count); ++ requeue_task(p); ++ ++ /* ++ * Since we are going to call schedule() anyway, there's ++ * no need to preempt or enable interrupts: ++ */ ++ __release(grq.lock); ++ spin_release(&grq.lock.dep_map, 1, _THIS_IP_); ++ do_raw_spin_unlock(&grq.lock); ++ sched_preempt_enable_no_resched(); ++ ++ schedule(); ++ ++ return 0; ++} ++ ++static inline bool should_resched(void) ++{ ++ return need_resched() && !(preempt_count() & PREEMPT_ACTIVE); ++} ++ ++static void __cond_resched(void) ++{ ++ add_preempt_count(PREEMPT_ACTIVE); ++ schedule(); ++ sub_preempt_count(PREEMPT_ACTIVE); ++} ++ ++int __sched _cond_resched(void) ++{ ++ if (should_resched()) { ++ __cond_resched(); ++ return 1; ++ } ++ return 0; ++} ++EXPORT_SYMBOL(_cond_resched); ++ ++/* ++ * __cond_resched_lock() - if a reschedule is pending, drop the given lock, ++ * call schedule, and on return reacquire the lock. ++ * ++ * This works OK both with and without CONFIG_PREEMPT. We do strange low-level ++ * operations here to prevent schedule() from being called twice (once via ++ * spin_unlock(), once by hand). ++ */ ++int __cond_resched_lock(spinlock_t *lock) ++{ ++ int resched = should_resched(); ++ int ret = 0; ++ ++ lockdep_assert_held(lock); ++ ++ if (spin_needbreak(lock) || resched) { ++ spin_unlock(lock); ++ if (resched) ++ __cond_resched(); ++ else ++ cpu_relax(); ++ ret = 1; ++ spin_lock(lock); ++ } ++ return ret; ++} ++EXPORT_SYMBOL(__cond_resched_lock); ++ ++int __sched __cond_resched_softirq(void) ++{ ++ BUG_ON(!in_softirq()); ++ ++ if (should_resched()) { ++ local_bh_enable(); ++ __cond_resched(); ++ local_bh_disable(); ++ return 1; ++ } ++ return 0; ++} ++EXPORT_SYMBOL(__cond_resched_softirq); ++ ++/** ++ * yield - yield the current processor to other threads. ++ * ++ * Do not ever use this function, there's a 99% chance you're doing it wrong. ++ * ++ * The scheduler is at all times free to pick the calling task as the most ++ * eligible task to run, if removing the yield() call from your code breaks ++ * it, its already broken. ++ * ++ * Typical broken usage is: ++ * ++ * while (!event) ++ * yield(); ++ * ++ * where one assumes that yield() will let 'the other' process run that will ++ * make event true. If the current task is a SCHED_FIFO task that will never ++ * happen. Never use yield() as a progress guarantee!! ++ * ++ * If you want to use yield() to wait for something, use wait_event(). ++ * If you want to use yield() to be 'nice' for others, use cond_resched(). ++ * If you still want to use yield(), do not! ++ */ ++void __sched yield(void) ++{ ++ set_current_state(TASK_RUNNING); ++ sys_sched_yield(); ++} ++EXPORT_SYMBOL(yield); ++ ++/** ++ * yield_to - yield the current processor to another thread in ++ * your thread group, or accelerate that thread toward the ++ * processor it's on. ++ * @p: target task ++ * @preempt: whether task preemption is allowed or not ++ * ++ * It's the caller's job to ensure that the target task struct ++ * can't go away on us before we can do any checks. ++ * ++ * Return: ++ * true (>0) if we indeed boosted the target task. ++ * false (0) if we failed to boost the target. ++ * -ESRCH if there's no task to yield to. ++ */ ++bool __sched yield_to(struct task_struct *p, bool preempt) ++{ ++ unsigned long flags; ++ int yielded = 0; ++ struct rq *rq; ++ ++ rq = this_rq(); ++ grq_lock_irqsave(&flags); ++ if (task_running(p) || p->state) { ++ yielded = -ESRCH; ++ goto out_unlock; ++ } ++ yielded = 1; ++ if (p->deadline > rq->rq_deadline) ++ p->deadline = rq->rq_deadline; ++ p->time_slice += rq->rq_time_slice; ++ rq->rq_time_slice = 0; ++ if (p->time_slice > timeslice()) ++ p->time_slice = timeslice(); ++ set_tsk_need_resched(rq->curr); ++out_unlock: ++ grq_unlock_irqrestore(&flags); ++ ++ if (yielded > 0) ++ schedule(); ++ return yielded; ++} ++EXPORT_SYMBOL_GPL(yield_to); ++ ++/* ++ * This task is about to go to sleep on IO. Increment rq->nr_iowait so ++ * that process accounting knows that this is a task in IO wait state. ++ * ++ * But don't do that if it is a deliberate, throttling IO wait (this task ++ * has set its backing_dev_info: the queue against which it should throttle) ++ */ ++void __sched io_schedule(void) ++{ ++ struct rq *rq = raw_rq(); ++ ++ delayacct_blkio_start(); ++ atomic_inc(&rq->nr_iowait); ++ blk_flush_plug(current); ++ current->in_iowait = 1; ++ schedule(); ++ current->in_iowait = 0; ++ atomic_dec(&rq->nr_iowait); ++ delayacct_blkio_end(); ++} ++EXPORT_SYMBOL(io_schedule); ++ ++long __sched io_schedule_timeout(long timeout) ++{ ++ struct rq *rq = raw_rq(); ++ long ret; ++ ++ delayacct_blkio_start(); ++ atomic_inc(&rq->nr_iowait); ++ blk_flush_plug(current); ++ current->in_iowait = 1; ++ ret = schedule_timeout(timeout); ++ current->in_iowait = 0; ++ atomic_dec(&rq->nr_iowait); ++ delayacct_blkio_end(); ++ return ret; ++} ++ ++/** ++ * sys_sched_get_priority_max - return maximum RT priority. ++ * @policy: scheduling class. ++ * ++ * Return: On success, this syscall returns the maximum ++ * rt_priority that can be used by a given scheduling class. ++ * On failure, a negative error code is returned. ++ */ ++SYSCALL_DEFINE1(sched_get_priority_max, int, policy) ++{ ++ int ret = -EINVAL; ++ ++ switch (policy) { ++ case SCHED_FIFO: ++ case SCHED_RR: ++ ret = MAX_USER_RT_PRIO-1; ++ break; ++ case SCHED_NORMAL: ++ case SCHED_BATCH: ++ case SCHED_ISO: ++ case SCHED_IDLEPRIO: ++ ret = 0; ++ break; ++ } ++ return ret; ++} ++ ++/** ++ * sys_sched_get_priority_min - return minimum RT priority. ++ * @policy: scheduling class. ++ * ++ * Return: On success, this syscall returns the minimum ++ * rt_priority that can be used by a given scheduling class. ++ * On failure, a negative error code is returned. ++ */ ++SYSCALL_DEFINE1(sched_get_priority_min, int, policy) ++{ ++ int ret = -EINVAL; ++ ++ switch (policy) { ++ case SCHED_FIFO: ++ case SCHED_RR: ++ ret = 1; ++ break; ++ case SCHED_NORMAL: ++ case SCHED_BATCH: ++ case SCHED_ISO: ++ case SCHED_IDLEPRIO: ++ ret = 0; ++ break; ++ } ++ return ret; ++} ++ ++/** ++ * sys_sched_rr_get_interval - return the default timeslice of a process. ++ * @pid: pid of the process. ++ * @interval: userspace pointer to the timeslice value. ++ * ++ * ++ * Return: On success, 0 and the timeslice is in @interval. Otherwise, ++ * an error code. ++ */ ++SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid, ++ struct timespec __user *, interval) ++{ ++ struct task_struct *p; ++ unsigned int time_slice; ++ unsigned long flags; ++ int retval; ++ struct timespec t; ++ ++ if (pid < 0) ++ return -EINVAL; ++ ++ retval = -ESRCH; ++ rcu_read_lock(); ++ p = find_process_by_pid(pid); ++ if (!p) ++ goto out_unlock; ++ ++ retval = security_task_getscheduler(p); ++ if (retval) ++ goto out_unlock; ++ ++ grq_lock_irqsave(&flags); ++ time_slice = p->policy == SCHED_FIFO ? 0 : MS_TO_NS(task_timeslice(p)); ++ grq_unlock_irqrestore(&flags); ++ ++ rcu_read_unlock(); ++ t = ns_to_timespec(time_slice); ++ retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0; ++ return retval; ++ ++out_unlock: ++ rcu_read_unlock(); ++ return retval; ++} ++ ++static const char stat_nam[] = TASK_STATE_TO_CHAR_STR; ++ ++void sched_show_task(struct task_struct *p) ++{ ++ unsigned long free = 0; ++ int ppid; ++ unsigned state; ++ ++ state = p->state ? __ffs(p->state) + 1 : 0; ++ printk(KERN_INFO "%-15.15s %c", p->comm, ++ state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?'); ++#if BITS_PER_LONG == 32 ++ if (state == TASK_RUNNING) ++ printk(KERN_CONT " running "); ++ else ++ printk(KERN_CONT " %08lx ", thread_saved_pc(p)); ++#else ++ if (state == TASK_RUNNING) ++ printk(KERN_CONT " running task "); ++ else ++ printk(KERN_CONT " %016lx ", thread_saved_pc(p)); ++#endif ++#ifdef CONFIG_DEBUG_STACK_USAGE ++ free = stack_not_used(p); ++#endif ++ rcu_read_lock(); ++ ppid = task_pid_nr(rcu_dereference(p->real_parent)); ++ rcu_read_unlock(); ++ printk(KERN_CONT "%5lu %5d %6d 0x%08lx\n", free, ++ task_pid_nr(p), ppid, ++ (unsigned long)task_thread_info(p)->flags); ++ ++ print_worker_info(KERN_INFO, p); ++ show_stack(p, NULL); ++} ++ ++void show_state_filter(unsigned long state_filter) ++{ ++ struct task_struct *g, *p; ++ ++#if BITS_PER_LONG == 32 ++ printk(KERN_INFO ++ " task PC stack pid father\n"); ++#else ++ printk(KERN_INFO ++ " task PC stack pid father\n"); ++#endif ++ rcu_read_lock(); ++ do_each_thread(g, p) { ++ /* ++ * reset the NMI-timeout, listing all files on a slow ++ * console might take a lot of time: ++ */ ++ touch_nmi_watchdog(); ++ if (!state_filter || (p->state & state_filter)) ++ sched_show_task(p); ++ } while_each_thread(g, p); ++ ++ touch_all_softlockup_watchdogs(); ++ ++ rcu_read_unlock(); ++ /* ++ * Only show locks if all tasks are dumped: ++ */ ++ if (!state_filter) ++ debug_show_all_locks(); ++} ++ ++void dump_cpu_task(int cpu) ++{ ++ pr_info("Task dump for CPU %d:\n", cpu); ++ sched_show_task(cpu_curr(cpu)); ++} ++ ++#ifdef CONFIG_SMP ++void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask) ++{ ++ cpumask_copy(tsk_cpus_allowed(p), new_mask); ++} ++#endif ++ ++/** ++ * init_idle - set up an idle thread for a given CPU ++ * @idle: task in question ++ * @cpu: cpu the idle task belongs to ++ * ++ * NOTE: this function does not set the idle thread's NEED_RESCHED ++ * flag, to make booting more robust. ++ */ ++void init_idle(struct task_struct *idle, int cpu) ++{ ++ struct rq *rq = cpu_rq(cpu); ++ unsigned long flags; ++ ++ time_grq_lock(rq, &flags); ++ idle->last_ran = rq->clock_task; ++ idle->state = TASK_RUNNING; ++ /* Setting prio to illegal value shouldn't matter when never queued */ ++ idle->prio = PRIO_LIMIT; ++ set_rq_task(rq, idle); ++ do_set_cpus_allowed(idle, &cpumask_of_cpu(cpu)); ++ /* Silence PROVE_RCU */ ++ rcu_read_lock(); ++ set_task_cpu(idle, cpu); ++ rcu_read_unlock(); ++ rq->curr = rq->idle = idle; ++ idle->on_cpu = 1; ++ grq_unlock_irqrestore(&flags); ++ ++ /* Set the preempt count _outside_ the spinlocks! */ ++ task_thread_info(idle)->preempt_count = 0; ++ ++ ftrace_graph_init_idle_task(idle, cpu); ++#if defined(CONFIG_SMP) ++ sprintf(idle->comm, "%s/%d", INIT_TASK_COMM, cpu); ++#endif ++} ++ ++#ifdef CONFIG_SMP ++#ifdef CONFIG_NO_HZ_COMMON ++void nohz_balance_enter_idle(int cpu) ++{ ++} ++ ++void select_nohz_load_balancer(int stop_tick) ++{ ++} ++ ++void set_cpu_sd_state_idle(void) {} ++#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) ++/** ++ * lowest_flag_domain - Return lowest sched_domain containing flag. ++ * @cpu: The cpu whose lowest level of sched domain is to ++ * be returned. ++ * @flag: The flag to check for the lowest sched_domain ++ * for the given cpu. ++ * ++ * Returns the lowest sched_domain of a cpu which contains the given flag. ++ */ ++static inline struct sched_domain *lowest_flag_domain(int cpu, int flag) ++{ ++ struct sched_domain *sd; ++ ++ for_each_domain(cpu, sd) ++ if (sd && (sd->flags & flag)) ++ break; ++ ++ return sd; ++} ++ ++/** ++ * for_each_flag_domain - Iterates over sched_domains containing the flag. ++ * @cpu: The cpu whose domains we're iterating over. ++ * @sd: variable holding the value of the power_savings_sd ++ * for cpu. ++ * @flag: The flag to filter the sched_domains to be iterated. ++ * ++ * Iterates over all the scheduler domains for a given cpu that has the 'flag' ++ * set, starting from the lowest sched_domain to the highest. ++ */ ++#define for_each_flag_domain(cpu, sd, flag) \ ++ for (sd = lowest_flag_domain(cpu, flag); \ ++ (sd && (sd->flags & flag)); sd = sd->parent) ++ ++#endif /* (CONFIG_SCHED_MC || CONFIG_SCHED_SMT) */ ++ ++static inline void resched_cpu(int cpu) ++{ ++ unsigned long flags; ++ ++ grq_lock_irqsave(&flags); ++ resched_task(cpu_curr(cpu)); ++ grq_unlock_irqrestore(&flags); ++} ++ ++/* ++ * In the semi idle case, use the nearest busy cpu for migrating timers ++ * from an idle cpu. This is good for power-savings. ++ * ++ * We don't do similar optimization for completely idle system, as ++ * selecting an idle cpu will add more delays to the timers than intended ++ * (as that cpu's timer base may not be uptodate wrt jiffies etc). ++ */ ++int get_nohz_timer_target(void) ++{ ++ int cpu = smp_processor_id(); ++ int i; ++ struct sched_domain *sd; ++ ++ rcu_read_lock(); ++ for_each_domain(cpu, sd) { ++ for_each_cpu(i, sched_domain_span(sd)) { ++ if (!idle_cpu(i)) ++ cpu = i; ++ goto unlock; ++ } ++ } ++unlock: ++ rcu_read_unlock(); ++ return cpu; ++} ++ ++/* ++ * When add_timer_on() enqueues a timer into the timer wheel of an ++ * idle CPU then this timer might expire before the next timer event ++ * which is scheduled to wake up that CPU. In case of a completely ++ * idle system the next event might even be infinite time into the ++ * future. wake_up_idle_cpu() ensures that the CPU is woken up and ++ * leaves the inner idle loop so the newly added timer is taken into ++ * account when the CPU goes back to idle and evaluates the timer ++ * wheel for the next timer event. ++ */ ++void wake_up_idle_cpu(int cpu) ++{ ++ struct task_struct *idle; ++ struct rq *rq; ++ ++ if (cpu == smp_processor_id()) ++ return; ++ ++ rq = cpu_rq(cpu); ++ idle = rq->idle; ++ ++ /* ++ * This is safe, as this function is called with the timer ++ * wheel base lock of (cpu) held. When the CPU is on the way ++ * to idle and has not yet set rq->curr to idle then it will ++ * be serialised on the timer wheel base lock and take the new ++ * timer into account automatically. ++ */ ++ if (unlikely(rq->curr != idle)) ++ return; ++ ++ /* ++ * We can set TIF_RESCHED on the idle task of the other CPU ++ * lockless. The worst case is that the other CPU runs the ++ * idle task through an additional NOOP schedule() ++ */ ++ set_tsk_need_resched(idle); ++ ++ /* NEED_RESCHED must be visible before we test polling */ ++ smp_mb(); ++ if (!tsk_is_polling(idle)) ++ smp_send_reschedule(cpu); ++} ++ ++void wake_up_nohz_cpu(int cpu) ++{ ++ wake_up_idle_cpu(cpu); ++} ++#endif /* CONFIG_NO_HZ_COMMON */ ++ ++/* ++ * Change a given task's CPU affinity. Migrate the thread to a ++ * proper CPU and schedule it away if the CPU it's executing on ++ * is removed from the allowed bitmask. ++ * ++ * NOTE: the caller must have a valid reference to the task, the ++ * task must not exit() & deallocate itself prematurely. The ++ * call is not atomic; no spinlocks may be held. ++ */ ++int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask) ++{ ++ bool running_wrong = false; ++ bool queued = false; ++ unsigned long flags; ++ struct rq *rq; ++ int ret = 0; ++ ++ rq = task_grq_lock(p, &flags); ++ ++ if (cpumask_equal(tsk_cpus_allowed(p), new_mask)) ++ goto out; ++ ++ if (!cpumask_intersects(new_mask, cpu_active_mask)) { ++ ret = -EINVAL; ++ goto out; ++ } ++ ++ queued = task_queued(p); ++ ++ do_set_cpus_allowed(p, new_mask); ++ ++ /* Can the task run on the task's current CPU? If so, we're done */ ++ if (cpumask_test_cpu(task_cpu(p), new_mask)) ++ goto out; ++ ++ if (task_running(p)) { ++ /* Task is running on the wrong cpu now, reschedule it. */ ++ if (rq == this_rq()) { ++ set_tsk_need_resched(p); ++ running_wrong = true; ++ } else ++ resched_task(p); ++ } else ++ set_task_cpu(p, cpumask_any_and(cpu_active_mask, new_mask)); ++ ++out: ++ if (queued) ++ try_preempt(p, rq); ++ task_grq_unlock(&flags); ++ ++ if (running_wrong) ++ _cond_resched(); ++ ++ return ret; ++} ++EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr); ++ ++#ifdef CONFIG_HOTPLUG_CPU ++extern struct task_struct *cpu_stopper_task; ++/* Run through task list and find tasks affined to the dead cpu, then remove ++ * that cpu from the list, enable cpu0 and set the zerobound flag. */ ++static void bind_zero(int src_cpu) ++{ ++ struct task_struct *p, *t, *stopper; ++ int bound = 0; ++ ++ if (src_cpu == 0) ++ return; ++ ++ stopper = per_cpu(cpu_stopper_task, src_cpu); ++ do_each_thread(t, p) { ++ if (p != stopper && cpu_isset(src_cpu, *tsk_cpus_allowed(p))) { ++ cpumask_clear_cpu(src_cpu, tsk_cpus_allowed(p)); ++ cpumask_set_cpu(0, tsk_cpus_allowed(p)); ++ p->zerobound = true; ++ bound++; ++ } ++ clear_sticky(p); ++ } while_each_thread(t, p); ++ ++ if (bound) { ++ printk(KERN_INFO "Removed affinity for %d processes to cpu %d\n", ++ bound, src_cpu); ++ } ++} ++ ++/* Find processes with the zerobound flag and reenable their affinity for the ++ * CPU coming alive. */ ++static void unbind_zero(int src_cpu) ++{ ++ int unbound = 0, zerobound = 0; ++ struct task_struct *p, *t; ++ ++ if (src_cpu == 0) ++ return; ++ ++ do_each_thread(t, p) { ++ if (!p->mm) ++ p->zerobound = false; ++ if (p->zerobound) { ++ unbound++; ++ cpumask_set_cpu(src_cpu, tsk_cpus_allowed(p)); ++ /* Once every CPU affinity has been re-enabled, remove ++ * the zerobound flag */ ++ if (cpumask_subset(cpu_possible_mask, tsk_cpus_allowed(p))) { ++ p->zerobound = false; ++ zerobound++; ++ } ++ } ++ } while_each_thread(t, p); ++ ++ if (unbound) { ++ printk(KERN_INFO "Added affinity for %d processes to cpu %d\n", ++ unbound, src_cpu); ++ } ++ if (zerobound) { ++ printk(KERN_INFO "Released forced binding to cpu0 for %d processes\n", ++ zerobound); ++ } ++} ++ ++/* ++ * Ensures that the idle task is using init_mm right before its cpu goes ++ * offline. ++ */ ++void idle_task_exit(void) ++{ ++ struct mm_struct *mm = current->active_mm; ++ ++ BUG_ON(cpu_online(smp_processor_id())); ++ ++ if (mm != &init_mm) ++ switch_mm(mm, &init_mm, current); ++ mmdrop(mm); ++} ++#else /* CONFIG_HOTPLUG_CPU */ ++static void unbind_zero(int src_cpu) {} ++#endif /* CONFIG_HOTPLUG_CPU */ ++ ++void sched_set_stop_task(int cpu, struct task_struct *stop) ++{ ++ struct sched_param stop_param = { .sched_priority = STOP_PRIO }; ++ struct sched_param start_param = { .sched_priority = 0 }; ++ struct task_struct *old_stop = cpu_rq(cpu)->stop; ++ ++ if (stop) { ++ /* ++ * Make it appear like a SCHED_FIFO task, its something ++ * userspace knows about and won't get confused about. ++ * ++ * Also, it will make PI more or less work without too ++ * much confusion -- but then, stop work should not ++ * rely on PI working anyway. ++ */ ++ sched_setscheduler_nocheck(stop, SCHED_FIFO, &stop_param); ++ } ++ ++ cpu_rq(cpu)->stop = stop; ++ ++ if (old_stop) { ++ /* ++ * Reset it back to a normal scheduling policy so that ++ * it can die in pieces. ++ */ ++ sched_setscheduler_nocheck(old_stop, SCHED_NORMAL, &start_param); ++ } ++} ++ ++ ++#if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL) ++ ++static struct ctl_table sd_ctl_dir[] = { ++ { ++ .procname = "sched_domain", ++ .mode = 0555, ++ }, ++ {} ++}; ++ ++static struct ctl_table sd_ctl_root[] = { ++ { ++ .procname = "kernel", ++ .mode = 0555, ++ .child = sd_ctl_dir, ++ }, ++ {} ++}; ++ ++static struct ctl_table *sd_alloc_ctl_entry(int n) ++{ ++ struct ctl_table *entry = ++ kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL); ++ ++ return entry; ++} ++ ++static void sd_free_ctl_entry(struct ctl_table **tablep) ++{ ++ struct ctl_table *entry; ++ ++ /* ++ * In the intermediate directories, both the child directory and ++ * procname are dynamically allocated and could fail but the mode ++ * will always be set. In the lowest directory the names are ++ * static strings and all have proc handlers. ++ */ ++ for (entry = *tablep; entry->mode; entry++) { ++ if (entry->child) ++ sd_free_ctl_entry(&entry->child); ++ if (entry->proc_handler == NULL) ++ kfree(entry->procname); ++ } ++ ++ kfree(*tablep); ++ *tablep = NULL; ++} ++ ++static void ++set_table_entry(struct ctl_table *entry, ++ const char *procname, void *data, int maxlen, ++ mode_t mode, proc_handler *proc_handler) ++{ ++ entry->procname = procname; ++ entry->data = data; ++ entry->maxlen = maxlen; ++ entry->mode = mode; ++ entry->proc_handler = proc_handler; ++} ++ ++static struct ctl_table * ++sd_alloc_ctl_domain_table(struct sched_domain *sd) ++{ ++ struct ctl_table *table = sd_alloc_ctl_entry(13); ++ ++ if (table == NULL) ++ return NULL; ++ ++ set_table_entry(&table[0], "min_interval", &sd->min_interval, ++ sizeof(long), 0644, proc_doulongvec_minmax); ++ set_table_entry(&table[1], "max_interval", &sd->max_interval, ++ sizeof(long), 0644, proc_doulongvec_minmax); ++ set_table_entry(&table[2], "busy_idx", &sd->busy_idx, ++ sizeof(int), 0644, proc_dointvec_minmax); ++ set_table_entry(&table[3], "idle_idx", &sd->idle_idx, ++ sizeof(int), 0644, proc_dointvec_minmax); ++ set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx, ++ sizeof(int), 0644, proc_dointvec_minmax); ++ set_table_entry(&table[5], "wake_idx", &sd->wake_idx, ++ sizeof(int), 0644, proc_dointvec_minmax); ++ set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx, ++ sizeof(int), 0644, proc_dointvec_minmax); ++ set_table_entry(&table[7], "busy_factor", &sd->busy_factor, ++ sizeof(int), 0644, proc_dointvec_minmax); ++ set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct, ++ sizeof(int), 0644, proc_dointvec_minmax); ++ set_table_entry(&table[9], "cache_nice_tries", ++ &sd->cache_nice_tries, ++ sizeof(int), 0644, proc_dointvec_minmax); ++ set_table_entry(&table[10], "flags", &sd->flags, ++ sizeof(int), 0644, proc_dointvec_minmax); ++ set_table_entry(&table[11], "name", sd->name, ++ CORENAME_MAX_SIZE, 0444, proc_dostring); ++ /* &table[12] is terminator */ ++ ++ return table; ++} ++ ++static struct ctl_table *sd_alloc_ctl_cpu_table(int cpu) ++{ ++ struct ctl_table *entry, *table; ++ struct sched_domain *sd; ++ int domain_num = 0, i; ++ char buf[32]; ++ ++ for_each_domain(cpu, sd) ++ domain_num++; ++ entry = table = sd_alloc_ctl_entry(domain_num + 1); ++ if (table == NULL) ++ return NULL; ++ ++ i = 0; ++ for_each_domain(cpu, sd) { ++ snprintf(buf, 32, "domain%d", i); ++ entry->procname = kstrdup(buf, GFP_KERNEL); ++ entry->mode = 0555; ++ entry->child = sd_alloc_ctl_domain_table(sd); ++ entry++; ++ i++; ++ } ++ return table; ++} ++ ++static struct ctl_table_header *sd_sysctl_header; ++static void register_sched_domain_sysctl(void) ++{ ++ int i, cpu_num = num_possible_cpus(); ++ struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1); ++ char buf[32]; ++ ++ WARN_ON(sd_ctl_dir[0].child); ++ sd_ctl_dir[0].child = entry; ++ ++ if (entry == NULL) ++ return; ++ ++ for_each_possible_cpu(i) { ++ snprintf(buf, 32, "cpu%d", i); ++ entry->procname = kstrdup(buf, GFP_KERNEL); ++ entry->mode = 0555; ++ entry->child = sd_alloc_ctl_cpu_table(i); ++ entry++; ++ } ++ ++ WARN_ON(sd_sysctl_header); ++ sd_sysctl_header = register_sysctl_table(sd_ctl_root); ++} ++ ++/* may be called multiple times per register */ ++static void unregister_sched_domain_sysctl(void) ++{ ++ if (sd_sysctl_header) ++ unregister_sysctl_table(sd_sysctl_header); ++ sd_sysctl_header = NULL; ++ if (sd_ctl_dir[0].child) ++ sd_free_ctl_entry(&sd_ctl_dir[0].child); ++} ++#else ++static void register_sched_domain_sysctl(void) ++{ ++} ++static void unregister_sched_domain_sysctl(void) ++{ ++} ++#endif ++ ++static void set_rq_online(struct rq *rq) ++{ ++ if (!rq->online) { ++ cpumask_set_cpu(cpu_of(rq), rq->rd->online); ++ rq->online = true; ++ } ++} ++ ++static void set_rq_offline(struct rq *rq) ++{ ++ if (rq->online) { ++ cpumask_clear_cpu(cpu_of(rq), rq->rd->online); ++ rq->online = false; ++ } ++} ++ ++/* ++ * migration_call - callback that gets triggered when a CPU is added. ++ */ ++static int ++migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) ++{ ++ int cpu = (long)hcpu; ++ unsigned long flags; ++ struct rq *rq = cpu_rq(cpu); ++#ifdef CONFIG_HOTPLUG_CPU ++ struct task_struct *idle = rq->idle; ++#endif ++ ++ switch (action & ~CPU_TASKS_FROZEN) { ++ ++ case CPU_UP_PREPARE: ++ break; ++ ++ case CPU_ONLINE: ++ /* Update our root-domain */ ++ grq_lock_irqsave(&flags); ++ if (rq->rd) { ++ BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span)); ++ ++ set_rq_online(rq); ++ } ++ unbind_zero(cpu); ++ grq.noc = num_online_cpus(); ++ grq_unlock_irqrestore(&flags); ++ break; ++ ++#ifdef CONFIG_HOTPLUG_CPU ++ case CPU_DEAD: ++ grq_lock_irq(); ++ set_rq_task(rq, idle); ++ update_clocks(rq); ++ grq_unlock_irq(); ++ break; ++ ++ case CPU_DYING: ++ sched_ttwu_pending(); ++ /* Update our root-domain */ ++ grq_lock_irqsave(&flags); ++ if (rq->rd) { ++ BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span)); ++ set_rq_offline(rq); ++ } ++ bind_zero(cpu); ++ grq.noc = num_online_cpus(); ++ grq_unlock_irqrestore(&flags); ++ break; ++#endif ++ } ++ return NOTIFY_OK; ++} ++ ++/* ++ * Register at high priority so that task migration (migrate_all_tasks) ++ * happens before everything else. This has to be lower priority than ++ * the notifier in the perf_counter subsystem, though. ++ */ ++static struct notifier_block migration_notifier = { ++ .notifier_call = migration_call, ++ .priority = CPU_PRI_MIGRATION, ++}; ++ ++static int sched_cpu_active(struct notifier_block *nfb, ++ unsigned long action, void *hcpu) ++{ ++ switch (action & ~CPU_TASKS_FROZEN) { ++ case CPU_STARTING: ++ case CPU_DOWN_FAILED: ++ set_cpu_active((long)hcpu, true); ++ return NOTIFY_OK; ++ default: ++ return NOTIFY_DONE; ++ } ++} ++ ++static int sched_cpu_inactive(struct notifier_block *nfb, ++ unsigned long action, void *hcpu) ++{ ++ switch (action & ~CPU_TASKS_FROZEN) { ++ case CPU_DOWN_PREPARE: ++ set_cpu_active((long)hcpu, false); ++ return NOTIFY_OK; ++ default: ++ return NOTIFY_DONE; ++ } ++} ++ ++int __init migration_init(void) ++{ ++ void *cpu = (void *)(long)smp_processor_id(); ++ int err; ++ ++ /* Initialise migration for the boot CPU */ ++ err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu); ++ BUG_ON(err == NOTIFY_BAD); ++ migration_call(&migration_notifier, CPU_ONLINE, cpu); ++ register_cpu_notifier(&migration_notifier); ++ ++ /* Register cpu active notifiers */ ++ cpu_notifier(sched_cpu_active, CPU_PRI_SCHED_ACTIVE); ++ cpu_notifier(sched_cpu_inactive, CPU_PRI_SCHED_INACTIVE); ++ ++ return 0; ++} ++early_initcall(migration_init); ++#endif ++ ++#ifdef CONFIG_SMP ++ ++static cpumask_var_t sched_domains_tmpmask; /* sched_domains_mutex */ ++ ++#ifdef CONFIG_SCHED_DEBUG ++ ++static __read_mostly int sched_debug_enabled; ++ ++static int __init sched_debug_setup(char *str) ++{ ++ sched_debug_enabled = 1; ++ ++ return 0; ++} ++early_param("sched_debug", sched_debug_setup); ++ ++static inline bool sched_debug(void) ++{ ++ return sched_debug_enabled; ++} ++ ++static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level, ++ struct cpumask *groupmask) ++{ ++ char str[256]; ++ ++ cpulist_scnprintf(str, sizeof(str), sched_domain_span(sd)); ++ cpumask_clear(groupmask); ++ ++ printk(KERN_DEBUG "%*s domain %d: ", level, "", level); ++ ++ if (!(sd->flags & SD_LOAD_BALANCE)) { ++ printk("does not load-balance\n"); ++ if (sd->parent) ++ printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain" ++ " has parent"); ++ return -1; ++ } ++ ++ printk(KERN_CONT "span %s level %s\n", str, sd->name); ++ ++ if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) { ++ printk(KERN_ERR "ERROR: domain->span does not contain " ++ "CPU%d\n", cpu); ++ } ++ ++ printk(KERN_CONT "\n"); ++ ++ if (!cpumask_equal(sched_domain_span(sd), groupmask)) ++ printk(KERN_ERR "ERROR: groups don't span domain->span\n"); ++ ++ if (sd->parent && ++ !cpumask_subset(groupmask, sched_domain_span(sd->parent))) ++ printk(KERN_ERR "ERROR: parent span is not a superset " ++ "of domain->span\n"); ++ return 0; ++} ++ ++static void sched_domain_debug(struct sched_domain *sd, int cpu) ++{ ++ int level = 0; ++ ++ if (!sched_debug_enabled) ++ return; ++ ++ if (!sd) { ++ printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu); ++ return; ++ } ++ ++ printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu); ++ ++ for (;;) { ++ if (sched_domain_debug_one(sd, cpu, level, sched_domains_tmpmask)) ++ break; ++ level++; ++ sd = sd->parent; ++ if (!sd) ++ break; ++ } ++} ++#else /* !CONFIG_SCHED_DEBUG */ ++# define sched_domain_debug(sd, cpu) do { } while (0) ++static inline bool sched_debug(void) ++{ ++ return false; ++} ++#endif /* CONFIG_SCHED_DEBUG */ ++ ++static int sd_degenerate(struct sched_domain *sd) ++{ ++ if (cpumask_weight(sched_domain_span(sd)) == 1) ++ return 1; ++ ++ /* Following flags don't use groups */ ++ if (sd->flags & (SD_WAKE_AFFINE)) ++ return 0; ++ ++ return 1; ++} ++ ++static int ++sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent) ++{ ++ unsigned long cflags = sd->flags, pflags = parent->flags; ++ ++ if (sd_degenerate(parent)) ++ return 1; ++ ++ if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent))) ++ return 0; ++ ++ if (~cflags & pflags) ++ return 0; ++ ++ return 1; ++} ++ ++static void free_rootdomain(struct rcu_head *rcu) ++{ ++ struct root_domain *rd = container_of(rcu, struct root_domain, rcu); ++ ++ cpupri_cleanup(&rd->cpupri); ++ free_cpumask_var(rd->rto_mask); ++ free_cpumask_var(rd->online); ++ free_cpumask_var(rd->span); ++ kfree(rd); ++} ++ ++static void rq_attach_root(struct rq *rq, struct root_domain *rd) ++{ ++ struct root_domain *old_rd = NULL; ++ unsigned long flags; ++ ++ grq_lock_irqsave(&flags); ++ ++ if (rq->rd) { ++ old_rd = rq->rd; ++ ++ if (cpumask_test_cpu(rq->cpu, old_rd->online)) ++ set_rq_offline(rq); ++ ++ cpumask_clear_cpu(rq->cpu, old_rd->span); ++ ++ /* ++ * If we dont want to free the old_rt yet then ++ * set old_rd to NULL to skip the freeing later ++ * in this function: ++ */ ++ if (!atomic_dec_and_test(&old_rd->refcount)) ++ old_rd = NULL; ++ } ++ ++ atomic_inc(&rd->refcount); ++ rq->rd = rd; ++ ++ cpumask_set_cpu(rq->cpu, rd->span); ++ if (cpumask_test_cpu(rq->cpu, cpu_active_mask)) ++ set_rq_online(rq); ++ ++ grq_unlock_irqrestore(&flags); ++ ++ if (old_rd) ++ call_rcu_sched(&old_rd->rcu, free_rootdomain); ++} ++ ++static int init_rootdomain(struct root_domain *rd) ++{ ++ memset(rd, 0, sizeof(*rd)); ++ ++ if (!alloc_cpumask_var(&rd->span, GFP_KERNEL)) ++ goto out; ++ if (!alloc_cpumask_var(&rd->online, GFP_KERNEL)) ++ goto free_span; ++ if (!alloc_cpumask_var(&rd->rto_mask, GFP_KERNEL)) ++ goto free_online; ++ ++ if (cpupri_init(&rd->cpupri) != 0) ++ goto free_rto_mask; ++ return 0; ++ ++free_rto_mask: ++ free_cpumask_var(rd->rto_mask); ++free_online: ++ free_cpumask_var(rd->online); ++free_span: ++ free_cpumask_var(rd->span); ++out: ++ return -ENOMEM; ++} ++ ++static void init_defrootdomain(void) ++{ ++ init_rootdomain(&def_root_domain); ++ ++ atomic_set(&def_root_domain.refcount, 1); ++} ++ ++static struct root_domain *alloc_rootdomain(void) ++{ ++ struct root_domain *rd; ++ ++ rd = kmalloc(sizeof(*rd), GFP_KERNEL); ++ if (!rd) ++ return NULL; ++ ++ if (init_rootdomain(rd) != 0) { ++ kfree(rd); ++ return NULL; ++ } ++ ++ return rd; ++} ++ ++static void free_sched_domain(struct rcu_head *rcu) ++{ ++ struct sched_domain *sd = container_of(rcu, struct sched_domain, rcu); ++ ++ kfree(sd); ++} ++ ++static void destroy_sched_domain(struct sched_domain *sd, int cpu) ++{ ++ call_rcu(&sd->rcu, free_sched_domain); ++} ++ ++static void destroy_sched_domains(struct sched_domain *sd, int cpu) ++{ ++ for (; sd; sd = sd->parent) ++ destroy_sched_domain(sd, cpu); ++} ++ ++/* ++ * Attach the domain 'sd' to 'cpu' as its base domain. Callers must ++ * hold the hotplug lock. ++ */ ++static void ++cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu) ++{ ++ struct rq *rq = cpu_rq(cpu); ++ struct sched_domain *tmp; ++ ++ /* Remove the sched domains which do not contribute to scheduling. */ ++ for (tmp = sd; tmp; ) { ++ struct sched_domain *parent = tmp->parent; ++ if (!parent) ++ break; ++ ++ if (sd_parent_degenerate(tmp, parent)) { ++ tmp->parent = parent->parent; ++ if (parent->parent) ++ parent->parent->child = tmp; ++ /* ++ * Transfer SD_PREFER_SIBLING down in case of a ++ * degenerate parent; the spans match for this ++ * so the property transfers. ++ */ ++ if (parent->flags & SD_PREFER_SIBLING) ++ tmp->flags |= SD_PREFER_SIBLING; ++ destroy_sched_domain(parent, cpu); ++ } else ++ tmp = tmp->parent; ++ } ++ ++ if (sd && sd_degenerate(sd)) { ++ tmp = sd; ++ sd = sd->parent; ++ destroy_sched_domain(tmp, cpu); ++ if (sd) ++ sd->child = NULL; ++ } ++ ++ sched_domain_debug(sd, cpu); ++ ++ rq_attach_root(rq, rd); ++ tmp = rq->sd; ++ rcu_assign_pointer(rq->sd, sd); ++ destroy_sched_domains(tmp, cpu); ++} ++ ++/* cpus with isolated domains */ ++static cpumask_var_t cpu_isolated_map; ++ ++/* Setup the mask of cpus configured for isolated domains */ ++static int __init isolated_cpu_setup(char *str) ++{ ++ alloc_bootmem_cpumask_var(&cpu_isolated_map); ++ cpulist_parse(str, cpu_isolated_map); ++ return 1; ++} ++ ++__setup("isolcpus=", isolated_cpu_setup); ++ ++static const struct cpumask *cpu_cpu_mask(int cpu) ++{ ++ return cpumask_of_node(cpu_to_node(cpu)); ++} ++ ++struct sd_data { ++ struct sched_domain **__percpu sd; ++}; ++ ++struct s_data { ++ struct sched_domain ** __percpu sd; ++ struct root_domain *rd; ++}; ++ ++enum s_alloc { ++ sa_rootdomain, ++ sa_sd, ++ sa_sd_storage, ++ sa_none, ++}; ++ ++struct sched_domain_topology_level; ++ ++typedef struct sched_domain *(*sched_domain_init_f)(struct sched_domain_topology_level *tl, int cpu); ++typedef const struct cpumask *(*sched_domain_mask_f)(int cpu); ++ ++#define SDTL_OVERLAP 0x01 ++ ++struct sched_domain_topology_level { ++ sched_domain_init_f init; ++ sched_domain_mask_f mask; ++ int flags; ++ int numa_level; ++ struct sd_data data; ++}; ++ ++/* ++ * Initializers for schedule domains ++ * Non-inlined to reduce accumulated stack pressure in build_sched_domains() ++ */ ++ ++#ifdef CONFIG_SCHED_DEBUG ++# define SD_INIT_NAME(sd, type) sd->name = #type ++#else ++# define SD_INIT_NAME(sd, type) do { } while (0) ++#endif ++ ++#define SD_INIT_FUNC(type) \ ++static noinline struct sched_domain * \ ++sd_init_##type(struct sched_domain_topology_level *tl, int cpu) \ ++{ \ ++ struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); \ ++ *sd = SD_##type##_INIT; \ ++ SD_INIT_NAME(sd, type); \ ++ sd->private = &tl->data; \ ++ return sd; \ ++} ++ ++SD_INIT_FUNC(CPU) ++#ifdef CONFIG_SCHED_SMT ++ SD_INIT_FUNC(SIBLING) ++#endif ++#ifdef CONFIG_SCHED_MC ++ SD_INIT_FUNC(MC) ++#endif ++#ifdef CONFIG_SCHED_BOOK ++ SD_INIT_FUNC(BOOK) ++#endif ++ ++static int default_relax_domain_level = -1; ++int sched_domain_level_max; ++ ++static int __init setup_relax_domain_level(char *str) ++{ ++ if (kstrtoint(str, 0, &default_relax_domain_level)) ++ pr_warn("Unable to set relax_domain_level\n"); ++ ++ return 1; ++} ++__setup("relax_domain_level=", setup_relax_domain_level); ++ ++static void set_domain_attribute(struct sched_domain *sd, ++ struct sched_domain_attr *attr) ++{ ++ int request; ++ ++ if (!attr || attr->relax_domain_level < 0) { ++ if (default_relax_domain_level < 0) ++ return; ++ else ++ request = default_relax_domain_level; ++ } else ++ request = attr->relax_domain_level; ++ if (request < sd->level) { ++ /* turn off idle balance on this domain */ ++ sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); ++ } else { ++ /* turn on idle balance on this domain */ ++ sd->flags |= (SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); ++ } ++} ++ ++static void __sdt_free(const struct cpumask *cpu_map); ++static int __sdt_alloc(const struct cpumask *cpu_map); ++ ++static void __free_domain_allocs(struct s_data *d, enum s_alloc what, ++ const struct cpumask *cpu_map) ++{ ++ switch (what) { ++ case sa_rootdomain: ++ if (!atomic_read(&d->rd->refcount)) ++ free_rootdomain(&d->rd->rcu); /* fall through */ ++ case sa_sd: ++ free_percpu(d->sd); /* fall through */ ++ case sa_sd_storage: ++ __sdt_free(cpu_map); /* fall through */ ++ case sa_none: ++ break; ++ } ++} ++ ++static enum s_alloc __visit_domain_allocation_hell(struct s_data *d, ++ const struct cpumask *cpu_map) ++{ ++ memset(d, 0, sizeof(*d)); ++ ++ if (__sdt_alloc(cpu_map)) ++ return sa_sd_storage; ++ d->sd = alloc_percpu(struct sched_domain *); ++ if (!d->sd) ++ return sa_sd_storage; ++ d->rd = alloc_rootdomain(); ++ if (!d->rd) ++ return sa_sd; ++ return sa_rootdomain; ++} ++ ++/* ++ * NULL the sd_data elements we've used to build the sched_domain ++ * structure so that the subsequent __free_domain_allocs() ++ * will not free the data we're using. ++ */ ++static void claim_allocations(int cpu, struct sched_domain *sd) ++{ ++ struct sd_data *sdd = sd->private; ++ ++ WARN_ON_ONCE(*per_cpu_ptr(sdd->sd, cpu) != sd); ++ *per_cpu_ptr(sdd->sd, cpu) = NULL; ++} ++ ++#ifdef CONFIG_SCHED_SMT ++static const struct cpumask *cpu_smt_mask(int cpu) ++{ ++ return topology_thread_cpumask(cpu); ++} ++#endif ++ ++/* ++ * Topology list, bottom-up. ++ */ ++static struct sched_domain_topology_level default_topology[] = { ++#ifdef CONFIG_SCHED_SMT ++ { sd_init_SIBLING, cpu_smt_mask, }, ++#endif ++#ifdef CONFIG_SCHED_MC ++ { sd_init_MC, cpu_coregroup_mask, }, ++#endif ++#ifdef CONFIG_SCHED_BOOK ++ { sd_init_BOOK, cpu_book_mask, }, ++#endif ++ { sd_init_CPU, cpu_cpu_mask, }, ++ { NULL, }, ++}; ++ ++static struct sched_domain_topology_level *sched_domain_topology = default_topology; ++ ++#define for_each_sd_topology(tl) \ ++ for (tl = sched_domain_topology; tl->init; tl++) ++ ++#ifdef CONFIG_NUMA ++ ++static int sched_domains_numa_levels; ++static int *sched_domains_numa_distance; ++static struct cpumask ***sched_domains_numa_masks; ++static int sched_domains_curr_level; ++ ++static inline int sd_local_flags(int level) ++{ ++ if (sched_domains_numa_distance[level] > RECLAIM_DISTANCE) ++ return 0; ++ ++ return SD_BALANCE_EXEC | SD_BALANCE_FORK | SD_WAKE_AFFINE; ++} ++ ++static struct sched_domain * ++sd_numa_init(struct sched_domain_topology_level *tl, int cpu) ++{ ++ struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); ++ int level = tl->numa_level; ++ int sd_weight = cpumask_weight( ++ sched_domains_numa_masks[level][cpu_to_node(cpu)]); ++ ++ *sd = (struct sched_domain){ ++ .min_interval = sd_weight, ++ .max_interval = 2*sd_weight, ++ .busy_factor = 32, ++ .imbalance_pct = 125, ++ .cache_nice_tries = 2, ++ .busy_idx = 3, ++ .idle_idx = 2, ++ .newidle_idx = 0, ++ .wake_idx = 0, ++ .forkexec_idx = 0, ++ ++ .flags = 1*SD_LOAD_BALANCE ++ | 1*SD_BALANCE_NEWIDLE ++ | 0*SD_BALANCE_EXEC ++ | 0*SD_BALANCE_FORK ++ | 0*SD_BALANCE_WAKE ++ | 0*SD_WAKE_AFFINE ++ | 0*SD_SHARE_CPUPOWER ++ | 0*SD_SHARE_PKG_RESOURCES ++ | 1*SD_SERIALIZE ++ | 0*SD_PREFER_SIBLING ++ | sd_local_flags(level) ++ , ++ .last_balance = jiffies, ++ .balance_interval = sd_weight, ++ }; ++ SD_INIT_NAME(sd, NUMA); ++ sd->private = &tl->data; ++ ++ /* ++ * Ugly hack to pass state to sd_numa_mask()... ++ */ ++ sched_domains_curr_level = tl->numa_level; ++ ++ return sd; ++} ++ ++static const struct cpumask *sd_numa_mask(int cpu) ++{ ++ return sched_domains_numa_masks[sched_domains_curr_level][cpu_to_node(cpu)]; ++} ++ ++static void sched_numa_warn(const char *str) ++{ ++ static int done = false; ++ int i,j; ++ ++ if (done) ++ return; ++ ++ done = true; ++ ++ printk(KERN_WARNING "ERROR: %s\n\n", str); ++ ++ for (i = 0; i < nr_node_ids; i++) { ++ printk(KERN_WARNING " "); ++ for (j = 0; j < nr_node_ids; j++) ++ printk(KERN_CONT "%02d ", node_distance(i,j)); ++ printk(KERN_CONT "\n"); ++ } ++ printk(KERN_WARNING "\n"); ++} ++ ++static bool find_numa_distance(int distance) ++{ ++ int i; ++ ++ if (distance == node_distance(0, 0)) ++ return true; ++ ++ for (i = 0; i < sched_domains_numa_levels; i++) { ++ if (sched_domains_numa_distance[i] == distance) ++ return true; ++ } ++ ++ return false; ++} ++ ++static void sched_init_numa(void) ++{ ++ int next_distance, curr_distance = node_distance(0, 0); ++ struct sched_domain_topology_level *tl; ++ int level = 0; ++ int i, j, k; ++ ++ sched_domains_numa_distance = kzalloc(sizeof(int) * nr_node_ids, GFP_KERNEL); ++ if (!sched_domains_numa_distance) ++ return; ++ ++ /* ++ * O(nr_nodes^2) deduplicating selection sort -- in order to find the ++ * unique distances in the node_distance() table. ++ * ++ * Assumes node_distance(0,j) includes all distances in ++ * node_distance(i,j) in order to avoid cubic time. ++ */ ++ next_distance = curr_distance; ++ for (i = 0; i < nr_node_ids; i++) { ++ for (j = 0; j < nr_node_ids; j++) { ++ for (k = 0; k < nr_node_ids; k++) { ++ int distance = node_distance(i, k); ++ ++ if (distance > curr_distance && ++ (distance < next_distance || ++ next_distance == curr_distance)) ++ next_distance = distance; ++ ++ /* ++ * While not a strong assumption it would be nice to know ++ * about cases where if node A is connected to B, B is not ++ * equally connected to A. ++ */ ++ if (sched_debug() && node_distance(k, i) != distance) ++ sched_numa_warn("Node-distance not symmetric"); ++ ++ if (sched_debug() && i && !find_numa_distance(distance)) ++ sched_numa_warn("Node-0 not representative"); ++ } ++ if (next_distance != curr_distance) { ++ sched_domains_numa_distance[level++] = next_distance; ++ sched_domains_numa_levels = level; ++ curr_distance = next_distance; ++ } else break; ++ } ++ ++ /* ++ * In case of sched_debug() we verify the above assumption. ++ */ ++ if (!sched_debug()) ++ break; ++ } ++ /* ++ * 'level' contains the number of unique distances, excluding the ++ * identity distance node_distance(i,i). ++ * ++ * The sched_domains_numa_distance[] array includes the actual distance ++ * numbers. ++ */ ++ ++ /* ++ * Here, we should temporarily reset sched_domains_numa_levels to 0. ++ * If it fails to allocate memory for array sched_domains_numa_masks[][], ++ * the array will contain less then 'level' members. This could be ++ * dangerous when we use it to iterate array sched_domains_numa_masks[][] ++ * in other functions. ++ * ++ * We reset it to 'level' at the end of this function. ++ */ ++ sched_domains_numa_levels = 0; ++ ++ sched_domains_numa_masks = kzalloc(sizeof(void *) * level, GFP_KERNEL); ++ if (!sched_domains_numa_masks) ++ return; ++ ++ /* ++ * Now for each level, construct a mask per node which contains all ++ * cpus of nodes that are that many hops away from us. ++ */ ++ for (i = 0; i < level; i++) { ++ sched_domains_numa_masks[i] = ++ kzalloc(nr_node_ids * sizeof(void *), GFP_KERNEL); ++ if (!sched_domains_numa_masks[i]) ++ return; ++ ++ for (j = 0; j < nr_node_ids; j++) { ++ struct cpumask *mask = kzalloc(cpumask_size(), GFP_KERNEL); ++ if (!mask) ++ return; ++ ++ sched_domains_numa_masks[i][j] = mask; ++ ++ for (k = 0; k < nr_node_ids; k++) { ++ if (node_distance(j, k) > sched_domains_numa_distance[i]) ++ continue; ++ ++ cpumask_or(mask, mask, cpumask_of_node(k)); ++ } ++ } ++ } ++ ++ tl = kzalloc((ARRAY_SIZE(default_topology) + level) * ++ sizeof(struct sched_domain_topology_level), GFP_KERNEL); ++ if (!tl) ++ return; ++ ++ /* ++ * Copy the default topology bits.. ++ */ ++ for (i = 0; default_topology[i].init; i++) ++ tl[i] = default_topology[i]; ++ ++ /* ++ * .. and append 'j' levels of NUMA goodness. ++ */ ++ for (j = 0; j < level; i++, j++) { ++ tl[i] = (struct sched_domain_topology_level){ ++ .init = sd_numa_init, ++ .mask = sd_numa_mask, ++ .flags = SDTL_OVERLAP, ++ .numa_level = j, ++ }; ++ } ++ ++ sched_domain_topology = tl; ++ ++ sched_domains_numa_levels = level; ++} ++ ++static void sched_domains_numa_masks_set(int cpu) ++{ ++ int i, j; ++ int node = cpu_to_node(cpu); ++ ++ for (i = 0; i < sched_domains_numa_levels; i++) { ++ for (j = 0; j < nr_node_ids; j++) { ++ if (node_distance(j, node) <= sched_domains_numa_distance[i]) ++ cpumask_set_cpu(cpu, sched_domains_numa_masks[i][j]); ++ } ++ } ++} ++ ++static void sched_domains_numa_masks_clear(int cpu) ++{ ++ int i, j; ++ for (i = 0; i < sched_domains_numa_levels; i++) { ++ for (j = 0; j < nr_node_ids; j++) ++ cpumask_clear_cpu(cpu, sched_domains_numa_masks[i][j]); ++ } ++} ++ ++/* ++ * Update sched_domains_numa_masks[level][node] array when new cpus ++ * are onlined. ++ */ ++static int sched_domains_numa_masks_update(struct notifier_block *nfb, ++ unsigned long action, ++ void *hcpu) ++{ ++ int cpu = (long)hcpu; ++ ++ switch (action & ~CPU_TASKS_FROZEN) { ++ case CPU_ONLINE: ++ sched_domains_numa_masks_set(cpu); ++ break; ++ ++ case CPU_DEAD: ++ sched_domains_numa_masks_clear(cpu); ++ break; ++ ++ default: ++ return NOTIFY_DONE; ++ } ++ ++ return NOTIFY_OK; ++} ++#else ++static inline void sched_init_numa(void) ++{ ++} ++ ++static int sched_domains_numa_masks_update(struct notifier_block *nfb, ++ unsigned long action, ++ void *hcpu) ++{ ++ return 0; ++} ++#endif /* CONFIG_NUMA */ ++ ++static int __sdt_alloc(const struct cpumask *cpu_map) ++{ ++ struct sched_domain_topology_level *tl; ++ int j; ++ ++ for_each_sd_topology(tl) { ++ struct sd_data *sdd = &tl->data; ++ ++ sdd->sd = alloc_percpu(struct sched_domain *); ++ if (!sdd->sd) ++ return -ENOMEM; ++ ++ for_each_cpu(j, cpu_map) { ++ struct sched_domain *sd; ++ ++ sd = kzalloc_node(sizeof(struct sched_domain) + cpumask_size(), ++ GFP_KERNEL, cpu_to_node(j)); ++ if (!sd) ++ return -ENOMEM; ++ ++ *per_cpu_ptr(sdd->sd, j) = sd; ++ } ++ } ++ ++ return 0; ++} ++ ++static void __sdt_free(const struct cpumask *cpu_map) ++{ ++ struct sched_domain_topology_level *tl; ++ int j; ++ ++ for_each_sd_topology(tl) { ++ struct sd_data *sdd = &tl->data; ++ ++ for_each_cpu(j, cpu_map) { ++ struct sched_domain *sd; ++ ++ if (sdd->sd) { ++ sd = *per_cpu_ptr(sdd->sd, j); ++ kfree(*per_cpu_ptr(sdd->sd, j)); ++ } ++ } ++ free_percpu(sdd->sd); ++ sdd->sd = NULL; ++ } ++} ++ ++struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl, ++ const struct cpumask *cpu_map, struct sched_domain_attr *attr, ++ struct sched_domain *child, int cpu) ++{ ++ struct sched_domain *sd = tl->init(tl, cpu); ++ if (!sd) ++ return child; ++ ++ cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu)); ++ if (child) { ++ sd->level = child->level + 1; ++ sched_domain_level_max = max(sched_domain_level_max, sd->level); ++ child->parent = sd; ++ sd->child = child; ++ } ++ set_domain_attribute(sd, attr); ++ ++ return sd; ++} ++ ++/* ++ * Build sched domains for a given set of cpus and attach the sched domains ++ * to the individual cpus ++ */ ++static int build_sched_domains(const struct cpumask *cpu_map, ++ struct sched_domain_attr *attr) ++{ ++ enum s_alloc alloc_state; ++ struct sched_domain *sd; ++ struct s_data d; ++ int i, ret = -ENOMEM; ++ ++ alloc_state = __visit_domain_allocation_hell(&d, cpu_map); ++ if (alloc_state != sa_rootdomain) ++ goto error; ++ ++ /* Set up domains for cpus specified by the cpu_map. */ ++ for_each_cpu(i, cpu_map) { ++ struct sched_domain_topology_level *tl; ++ ++ sd = NULL; ++ for_each_sd_topology(tl) { ++ sd = build_sched_domain(tl, cpu_map, attr, sd, i); ++ if (tl == sched_domain_topology) ++ *per_cpu_ptr(d.sd, i) = sd; ++ if (tl->flags & SDTL_OVERLAP) ++ sd->flags |= SD_OVERLAP; ++ if (cpumask_equal(cpu_map, sched_domain_span(sd))) ++ break; ++ } ++ } ++ ++ /* Calculate CPU power for physical packages and nodes */ ++ for (i = nr_cpumask_bits-1; i >= 0; i--) { ++ if (!cpumask_test_cpu(i, cpu_map)) ++ continue; ++ ++ for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { ++ claim_allocations(i, sd); ++ } ++ } ++ ++ /* Attach the domains */ ++ rcu_read_lock(); ++ for_each_cpu(i, cpu_map) { ++ sd = *per_cpu_ptr(d.sd, i); ++ cpu_attach_domain(sd, d.rd, i); ++ } ++ rcu_read_unlock(); ++ ++ ret = 0; ++error: ++ __free_domain_allocs(&d, alloc_state, cpu_map); ++ return ret; ++} ++ ++static cpumask_var_t *doms_cur; /* current sched domains */ ++static int ndoms_cur; /* number of sched domains in 'doms_cur' */ ++static struct sched_domain_attr *dattr_cur; ++ /* attribues of custom domains in 'doms_cur' */ ++ ++/* ++ * Special case: If a kmalloc of a doms_cur partition (array of ++ * cpumask) fails, then fallback to a single sched domain, ++ * as determined by the single cpumask fallback_doms. ++ */ ++static cpumask_var_t fallback_doms; ++ ++/* ++ * arch_update_cpu_topology lets virtualized architectures update the ++ * cpu core maps. It is supposed to return 1 if the topology changed ++ * or 0 if it stayed the same. ++ */ ++int __attribute__((weak)) arch_update_cpu_topology(void) ++{ ++ return 0; ++} ++ ++cpumask_var_t *alloc_sched_domains(unsigned int ndoms) ++{ ++ int i; ++ cpumask_var_t *doms; ++ ++ doms = kmalloc(sizeof(*doms) * ndoms, GFP_KERNEL); ++ if (!doms) ++ return NULL; ++ for (i = 0; i < ndoms; i++) { ++ if (!alloc_cpumask_var(&doms[i], GFP_KERNEL)) { ++ free_sched_domains(doms, i); ++ return NULL; ++ } ++ } ++ return doms; ++} ++ ++void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms) ++{ ++ unsigned int i; ++ for (i = 0; i < ndoms; i++) ++ free_cpumask_var(doms[i]); ++ kfree(doms); ++} ++ ++/* ++ * Set up scheduler domains and groups. Callers must hold the hotplug lock. ++ * For now this just excludes isolated cpus, but could be used to ++ * exclude other special cases in the future. ++ */ ++static int init_sched_domains(const struct cpumask *cpu_map) ++{ ++ int err; ++ ++ arch_update_cpu_topology(); ++ ndoms_cur = 1; ++ doms_cur = alloc_sched_domains(ndoms_cur); ++ if (!doms_cur) ++ doms_cur = &fallback_doms; ++ cpumask_andnot(doms_cur[0], cpu_map, cpu_isolated_map); ++ err = build_sched_domains(doms_cur[0], NULL); ++ register_sched_domain_sysctl(); ++ ++ return err; ++} ++ ++/* ++ * Detach sched domains from a group of cpus specified in cpu_map ++ * These cpus will now be attached to the NULL domain ++ */ ++static void detach_destroy_domains(const struct cpumask *cpu_map) ++{ ++ int i; ++ ++ rcu_read_lock(); ++ for_each_cpu(i, cpu_map) ++ cpu_attach_domain(NULL, &def_root_domain, i); ++ rcu_read_unlock(); ++} ++ ++/* handle null as "default" */ ++static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur, ++ struct sched_domain_attr *new, int idx_new) ++{ ++ struct sched_domain_attr tmp; ++ ++ /* fast path */ ++ if (!new && !cur) ++ return 1; ++ ++ tmp = SD_ATTR_INIT; ++ return !memcmp(cur ? (cur + idx_cur) : &tmp, ++ new ? (new + idx_new) : &tmp, ++ sizeof(struct sched_domain_attr)); ++} ++ ++/* ++ * Partition sched domains as specified by the 'ndoms_new' ++ * cpumasks in the array doms_new[] of cpumasks. This compares ++ * doms_new[] to the current sched domain partitioning, doms_cur[]. ++ * It destroys each deleted domain and builds each new domain. ++ * ++ * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'. ++ * The masks don't intersect (don't overlap.) We should setup one ++ * sched domain for each mask. CPUs not in any of the cpumasks will ++ * not be load balanced. If the same cpumask appears both in the ++ * current 'doms_cur' domains and in the new 'doms_new', we can leave ++ * it as it is. ++ * ++ * The passed in 'doms_new' should be allocated using ++ * alloc_sched_domains. This routine takes ownership of it and will ++ * free_sched_domains it when done with it. If the caller failed the ++ * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1, ++ * and partition_sched_domains() will fallback to the single partition ++ * 'fallback_doms', it also forces the domains to be rebuilt. ++ * ++ * If doms_new == NULL it will be replaced with cpu_online_mask. ++ * ndoms_new == 0 is a special case for destroying existing domains, ++ * and it will not create the default domain. ++ * ++ * Call with hotplug lock held ++ */ ++void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[], ++ struct sched_domain_attr *dattr_new) ++{ ++ int i, j, n; ++ int new_topology; ++ ++ mutex_lock(&sched_domains_mutex); ++ ++ /* always unregister in case we don't destroy any domains */ ++ unregister_sched_domain_sysctl(); ++ ++ /* Let architecture update cpu core mappings. */ ++ new_topology = arch_update_cpu_topology(); ++ ++ n = doms_new ? ndoms_new : 0; ++ ++ /* Destroy deleted domains */ ++ for (i = 0; i < ndoms_cur; i++) { ++ for (j = 0; j < n && !new_topology; j++) { ++ if (cpumask_equal(doms_cur[i], doms_new[j]) ++ && dattrs_equal(dattr_cur, i, dattr_new, j)) ++ goto match1; ++ } ++ /* no match - a current sched domain not in new doms_new[] */ ++ detach_destroy_domains(doms_cur[i]); ++match1: ++ ; ++ } ++ ++ n = ndoms_cur; ++ if (doms_new == NULL) { ++ n = 0; ++ doms_new = &fallback_doms; ++ cpumask_andnot(doms_new[0], cpu_active_mask, cpu_isolated_map); ++ WARN_ON_ONCE(dattr_new); ++ } ++ ++ /* Build new domains */ ++ for (i = 0; i < ndoms_new; i++) { ++ for (j = 0; j < n && !new_topology; j++) { ++ if (cpumask_equal(doms_new[i], doms_cur[j]) ++ && dattrs_equal(dattr_new, i, dattr_cur, j)) ++ goto match2; ++ } ++ /* no match - add a new doms_new */ ++ build_sched_domains(doms_new[i], dattr_new ? dattr_new + i : NULL); ++match2: ++ ; ++ } ++ ++ /* Remember the new sched domains */ ++ if (doms_cur != &fallback_doms) ++ free_sched_domains(doms_cur, ndoms_cur); ++ kfree(dattr_cur); /* kfree(NULL) is safe */ ++ doms_cur = doms_new; ++ dattr_cur = dattr_new; ++ ndoms_cur = ndoms_new; ++ ++ register_sched_domain_sysctl(); ++ ++ mutex_unlock(&sched_domains_mutex); ++} ++ ++static int num_cpus_frozen; /* used to mark begin/end of suspend/resume */ ++ ++/* ++ * Update cpusets according to cpu_active mask. If cpusets are ++ * disabled, cpuset_update_active_cpus() becomes a simple wrapper ++ * around partition_sched_domains(). ++ * ++ * If we come here as part of a suspend/resume, don't touch cpusets because we ++ * want to restore it back to its original state upon resume anyway. ++ */ ++static int cpuset_cpu_active(struct notifier_block *nfb, unsigned long action, ++ void *hcpu) ++{ ++ switch (action) { ++ case CPU_ONLINE_FROZEN: ++ case CPU_DOWN_FAILED_FROZEN: ++ ++ /* ++ * num_cpus_frozen tracks how many CPUs are involved in suspend ++ * resume sequence. As long as this is not the last online ++ * operation in the resume sequence, just build a single sched ++ * domain, ignoring cpusets. ++ */ ++ num_cpus_frozen--; ++ if (likely(num_cpus_frozen)) { ++ partition_sched_domains(1, NULL, NULL); ++ break; ++ } ++ ++ /* ++ * This is the last CPU online operation. So fall through and ++ * restore the original sched domains by considering the ++ * cpuset configurations. ++ */ ++ ++ case CPU_ONLINE: ++ case CPU_DOWN_FAILED: ++ cpuset_update_active_cpus(true); ++ break; ++ default: ++ return NOTIFY_DONE; ++ } ++ return NOTIFY_OK; ++} ++ ++static int cpuset_cpu_inactive(struct notifier_block *nfb, unsigned long action, ++ void *hcpu) ++{ ++ switch (action) { ++ case CPU_DOWN_PREPARE: ++ cpuset_update_active_cpus(false); ++ break; ++ case CPU_DOWN_PREPARE_FROZEN: ++ num_cpus_frozen++; ++ partition_sched_domains(1, NULL, NULL); ++ break; ++ default: ++ return NOTIFY_DONE; ++ } ++ return NOTIFY_OK; ++} ++ ++#if defined(CONFIG_SCHED_SMT) || defined(CONFIG_SCHED_MC) ++/* ++ * Cheaper version of the below functions in case support for SMT and MC is ++ * compiled in but CPUs have no siblings. ++ */ ++static bool sole_cpu_idle(int cpu) ++{ ++ return rq_idle(cpu_rq(cpu)); ++} ++#endif ++#ifdef CONFIG_SCHED_SMT ++/* All this CPU's SMT siblings are idle */ ++static bool siblings_cpu_idle(int cpu) ++{ ++ return cpumask_subset(&(cpu_rq(cpu)->smt_siblings), ++ &grq.cpu_idle_map); ++} ++#endif ++#ifdef CONFIG_SCHED_MC ++/* All this CPU's shared cache siblings are idle */ ++static bool cache_cpu_idle(int cpu) ++{ ++ return cpumask_subset(&(cpu_rq(cpu)->cache_siblings), ++ &grq.cpu_idle_map); ++} ++#endif ++ ++enum sched_domain_level { ++ SD_LV_NONE = 0, ++ SD_LV_SIBLING, ++ SD_LV_MC, ++ SD_LV_BOOK, ++ SD_LV_CPU, ++ SD_LV_NODE, ++ SD_LV_ALLNODES, ++ SD_LV_MAX ++}; ++ ++void __init sched_init_smp(void) ++{ ++ struct sched_domain *sd; ++ int cpu; ++ ++ cpumask_var_t non_isolated_cpus; ++ ++ alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL); ++ alloc_cpumask_var(&fallback_doms, GFP_KERNEL); ++ ++ sched_init_numa(); ++ ++ get_online_cpus(); ++ mutex_lock(&sched_domains_mutex); ++ init_sched_domains(cpu_active_mask); ++ cpumask_andnot(non_isolated_cpus, cpu_possible_mask, cpu_isolated_map); ++ if (cpumask_empty(non_isolated_cpus)) ++ cpumask_set_cpu(smp_processor_id(), non_isolated_cpus); ++ mutex_unlock(&sched_domains_mutex); ++ put_online_cpus(); ++ ++ hotcpu_notifier(sched_domains_numa_masks_update, CPU_PRI_SCHED_ACTIVE); ++ hotcpu_notifier(cpuset_cpu_active, CPU_PRI_CPUSET_ACTIVE); ++ hotcpu_notifier(cpuset_cpu_inactive, CPU_PRI_CPUSET_INACTIVE); ++ ++ /* Move init over to a non-isolated CPU */ ++ if (set_cpus_allowed_ptr(current, non_isolated_cpus) < 0) ++ BUG(); ++ free_cpumask_var(non_isolated_cpus); ++ ++ grq_lock_irq(); ++ /* ++ * Set up the relative cache distance of each online cpu from each ++ * other in a simple array for quick lookup. Locality is determined ++ * by the closest sched_domain that CPUs are separated by. CPUs with ++ * shared cache in SMT and MC are treated as local. Separate CPUs ++ * (within the same package or physically) within the same node are ++ * treated as not local. CPUs not even in the same domain (different ++ * nodes) are treated as very distant. ++ */ ++ for_each_online_cpu(cpu) { ++ struct rq *rq = cpu_rq(cpu); ++ ++ mutex_lock(&sched_domains_mutex); ++ for_each_domain(cpu, sd) { ++ int locality, other_cpu; ++ ++#ifdef CONFIG_SCHED_SMT ++ if (sd->level == SD_LV_SIBLING) { ++ for_each_cpu_mask(other_cpu, *sched_domain_span(sd)) ++ cpumask_set_cpu(other_cpu, &rq->smt_siblings); ++ } ++#endif ++#ifdef CONFIG_SCHED_MC ++ if (sd->level == SD_LV_MC) { ++ for_each_cpu_mask(other_cpu, *sched_domain_span(sd)) ++ cpumask_set_cpu(other_cpu, &rq->cache_siblings); ++ } ++#endif ++ if (sd->level <= SD_LV_SIBLING) ++ locality = 1; ++ else if (sd->level <= SD_LV_MC) ++ locality = 2; ++ else if (sd->level <= SD_LV_NODE) ++ locality = 3; ++ else ++ continue; ++ ++ for_each_cpu_mask(other_cpu, *sched_domain_span(sd)) { ++ if (locality < rq->cpu_locality[other_cpu]) ++ rq->cpu_locality[other_cpu] = locality; ++ } ++ } ++ mutex_unlock(&sched_domains_mutex); ++ ++ /* ++ * Each runqueue has its own function in case it doesn't have ++ * siblings of its own allowing mixed topologies. ++ */ ++#ifdef CONFIG_SCHED_SMT ++ if (cpus_weight(rq->smt_siblings) > 1) ++ rq->siblings_idle = siblings_cpu_idle; ++#endif ++#ifdef CONFIG_SCHED_MC ++ if (cpus_weight(rq->cache_siblings) > 1) ++ rq->cache_idle = cache_cpu_idle; ++#endif ++ } ++ grq_unlock_irq(); ++} ++#else ++void __init sched_init_smp(void) ++{ ++} ++#endif /* CONFIG_SMP */ ++ ++unsigned int sysctl_timer_migration = 1; ++ ++int in_sched_functions(unsigned long addr) ++{ ++ return in_lock_functions(addr) || ++ (addr >= (unsigned long)__sched_text_start ++ && addr < (unsigned long)__sched_text_end); ++} ++ ++void __init sched_init(void) ++{ ++ int i; ++ struct rq *rq; ++ ++ prio_ratios[0] = 128; ++ for (i = 1 ; i < PRIO_RANGE ; i++) ++ prio_ratios[i] = prio_ratios[i - 1] * 11 / 10; ++ ++ raw_spin_lock_init(&grq.lock); ++ grq.nr_running = grq.nr_uninterruptible = grq.nr_switches = 0; ++ grq.niffies = 0; ++ grq.last_jiffy = jiffies; ++ raw_spin_lock_init(&grq.iso_lock); ++ grq.iso_ticks = 0; ++ grq.iso_refractory = false; ++ grq.noc = 1; ++#ifdef CONFIG_SMP ++ init_defrootdomain(); ++ grq.qnr = grq.idle_cpus = 0; ++ cpumask_clear(&grq.cpu_idle_map); ++#else ++ uprq = &per_cpu(runqueues, 0); ++#endif ++ for_each_possible_cpu(i) { ++ rq = cpu_rq(i); ++ rq->user_pc = rq->nice_pc = rq->softirq_pc = rq->system_pc = ++ rq->iowait_pc = rq->idle_pc = 0; ++ rq->dither = false; ++#ifdef CONFIG_SMP ++ rq->sticky_task = NULL; ++ rq->last_niffy = 0; ++ rq->sd = NULL; ++ rq->rd = NULL; ++ rq->online = false; ++ rq->cpu = i; ++ rq_attach_root(rq, &def_root_domain); ++#endif ++ atomic_set(&rq->nr_iowait, 0); ++ } ++ ++#ifdef CONFIG_SMP ++ nr_cpu_ids = i; ++ /* ++ * Set the base locality for cpu cache distance calculation to ++ * "distant" (3). Make sure the distance from a CPU to itself is 0. ++ */ ++ for_each_possible_cpu(i) { ++ int j; ++ ++ rq = cpu_rq(i); ++#ifdef CONFIG_SCHED_SMT ++ cpumask_clear(&rq->smt_siblings); ++ cpumask_set_cpu(i, &rq->smt_siblings); ++ rq->siblings_idle = sole_cpu_idle; ++ cpumask_set_cpu(i, &rq->smt_siblings); ++#endif ++#ifdef CONFIG_SCHED_MC ++ cpumask_clear(&rq->cache_siblings); ++ cpumask_set_cpu(i, &rq->cache_siblings); ++ rq->cache_idle = sole_cpu_idle; ++ cpumask_set_cpu(i, &rq->cache_siblings); ++#endif ++ rq->cpu_locality = kmalloc(nr_cpu_ids * sizeof(int *), GFP_ATOMIC); ++ for_each_possible_cpu(j) { ++ if (i == j) ++ rq->cpu_locality[j] = 0; ++ else ++ rq->cpu_locality[j] = 4; ++ } ++ } ++#endif ++ ++ for (i = 0; i < PRIO_LIMIT; i++) ++ INIT_LIST_HEAD(grq.queue + i); ++ /* delimiter for bitsearch */ ++ __set_bit(PRIO_LIMIT, grq.prio_bitmap); ++ ++#ifdef CONFIG_PREEMPT_NOTIFIERS ++ INIT_HLIST_HEAD(&init_task.preempt_notifiers); ++#endif ++ ++#ifdef CONFIG_RT_MUTEXES ++ plist_head_init(&init_task.pi_waiters); ++#endif ++ ++ /* ++ * The boot idle thread does lazy MMU switching as well: ++ */ ++ atomic_inc(&init_mm.mm_count); ++ enter_lazy_tlb(&init_mm, current); ++ ++ /* ++ * Make us the idle thread. Technically, schedule() should not be ++ * called from this thread, however somewhere below it might be, ++ * but because we are the idle thread, we just pick up running again ++ * when this runqueue becomes "idle". ++ */ ++ init_idle(current, smp_processor_id()); ++ ++#ifdef CONFIG_SMP ++ zalloc_cpumask_var(&sched_domains_tmpmask, GFP_NOWAIT); ++ /* May be allocated at isolcpus cmdline parse time */ ++ if (cpu_isolated_map == NULL) ++ zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT); ++ idle_thread_set_boot_cpu(); ++#endif /* SMP */ ++} ++ ++#ifdef CONFIG_DEBUG_ATOMIC_SLEEP ++static inline int preempt_count_equals(int preempt_offset) ++{ ++ int nested = (preempt_count() & ~PREEMPT_ACTIVE) + rcu_preempt_depth(); ++ ++ return (nested == preempt_offset); ++} ++ ++void __might_sleep(const char *file, int line, int preempt_offset) ++{ ++ static unsigned long prev_jiffy; /* ratelimiting */ ++ ++ rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */ ++ if ((preempt_count_equals(preempt_offset) && !irqs_disabled()) || ++ system_state != SYSTEM_RUNNING || oops_in_progress) ++ return; ++ if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy) ++ return; ++ prev_jiffy = jiffies; ++ ++ printk(KERN_ERR ++ "BUG: sleeping function called from invalid context at %s:%d\n", ++ file, line); ++ printk(KERN_ERR ++ "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n", ++ in_atomic(), irqs_disabled(), ++ current->pid, current->comm); ++ ++ debug_show_held_locks(current); ++ if (irqs_disabled()) ++ print_irqtrace_events(current); ++ dump_stack(); ++} ++EXPORT_SYMBOL(__might_sleep); ++#endif ++ ++#ifdef CONFIG_MAGIC_SYSRQ ++void normalize_rt_tasks(void) ++{ ++ struct task_struct *g, *p; ++ unsigned long flags; ++ struct rq *rq; ++ int queued; ++ ++ read_lock_irqsave(&tasklist_lock, flags); ++ ++ do_each_thread(g, p) { ++ if (!rt_task(p) && !iso_task(p)) ++ continue; ++ ++ raw_spin_lock(&p->pi_lock); ++ rq = __task_grq_lock(p); ++ ++ queued = task_queued(p); ++ if (queued) ++ dequeue_task(p); ++ __setscheduler(p, rq, SCHED_NORMAL, 0); ++ if (queued) { ++ enqueue_task(p); ++ try_preempt(p, rq); ++ } ++ ++ __task_grq_unlock(); ++ raw_spin_unlock(&p->pi_lock); ++ } while_each_thread(g, p); ++ ++ read_unlock_irqrestore(&tasklist_lock, flags); ++} ++#endif /* CONFIG_MAGIC_SYSRQ */ ++ ++#if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) ++/* ++ * These functions are only useful for the IA64 MCA handling, or kdb. ++ * ++ * They can only be called when the whole system has been ++ * stopped - every CPU needs to be quiescent, and no scheduling ++ * activity can take place. Using them for anything else would ++ * be a serious bug, and as a result, they aren't even visible ++ * under any other configuration. ++ */ ++ ++/** ++ * curr_task - return the current task for a given cpu. ++ * @cpu: the processor in question. ++ * ++ * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! ++ * ++ * Return: The current task for @cpu. ++ */ ++struct task_struct *curr_task(int cpu) ++{ ++ return cpu_curr(cpu); ++} ++ ++#endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */ ++ ++#ifdef CONFIG_IA64 ++/** ++ * set_curr_task - set the current task for a given cpu. ++ * @cpu: the processor in question. ++ * @p: the task pointer to set. ++ * ++ * Description: This function must only be used when non-maskable interrupts ++ * are serviced on a separate stack. It allows the architecture to switch the ++ * notion of the current task on a cpu in a non-blocking manner. This function ++ * must be called with all CPU's synchronised, and interrupts disabled, the ++ * and caller must save the original value of the current task (see ++ * curr_task() above) and restore that value before reenabling interrupts and ++ * re-starting the system. ++ * ++ * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! ++ */ ++void set_curr_task(int cpu, struct task_struct *p) ++{ ++ cpu_curr(cpu) = p; ++} ++ ++#endif ++ ++/* ++ * Use precise platform statistics if available: ++ */ ++#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE ++void task_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st) ++{ ++ *ut = p->utime; ++ *st = p->stime; ++} ++ ++void thread_group_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st) ++{ ++ struct task_cputime cputime; ++ ++ thread_group_cputime(p, &cputime); ++ ++ *ut = cputime.utime; ++ *st = cputime.stime; ++} ++ ++void vtime_account_system_irqsafe(struct task_struct *tsk) ++{ ++ unsigned long flags; ++ ++ local_irq_save(flags); ++ vtime_account_system(tsk); ++ local_irq_restore(flags); ++} ++EXPORT_SYMBOL_GPL(vtime_account_system_irqsafe); ++ ++#ifndef __ARCH_HAS_VTIME_TASK_SWITCH ++void vtime_task_switch(struct task_struct *prev) ++{ ++ if (is_idle_task(prev)) ++ vtime_account_idle(prev); ++ else ++ vtime_account_system(prev); ++ ++ vtime_account_user(prev); ++ arch_vtime_task_switch(prev); ++} ++#endif ++ ++#else ++/* ++ * Perform (stime * rtime) / total, but avoid multiplication overflow by ++ * losing precision when the numbers are big. ++ */ ++static cputime_t scale_stime(u64 stime, u64 rtime, u64 total) ++{ ++ u64 scaled; ++ ++ for (;;) { ++ /* Make sure "rtime" is the bigger of stime/rtime */ ++ if (stime > rtime) { ++ u64 tmp = rtime; rtime = stime; stime = tmp; ++ } ++ ++ /* Make sure 'total' fits in 32 bits */ ++ if (total >> 32) ++ goto drop_precision; ++ ++ /* Does rtime (and thus stime) fit in 32 bits? */ ++ if (!(rtime >> 32)) ++ break; ++ ++ /* Can we just balance rtime/stime rather than dropping bits? */ ++ if (stime >> 31) ++ goto drop_precision; ++ ++ /* We can grow stime and shrink rtime and try to make them both fit */ ++ stime <<= 1; ++ rtime >>= 1; ++ continue; ++ ++drop_precision: ++ /* We drop from rtime, it has more bits than stime */ ++ rtime >>= 1; ++ total >>= 1; ++ } ++ ++ /* ++ * Make sure gcc understands that this is a 32x32->64 multiply, ++ * followed by a 64/32->64 divide. ++ */ ++ scaled = div_u64((u64) (u32) stime * (u64) (u32) rtime, (u32)total); ++ return (__force cputime_t) scaled; ++} ++ ++/* ++ * Adjust tick based cputime random precision against scheduler ++ * runtime accounting. ++ */ ++static void cputime_adjust(struct task_cputime *curr, ++ struct cputime *prev, ++ cputime_t *ut, cputime_t *st) ++{ ++ cputime_t rtime, stime, utime, total; ++ ++ stime = curr->stime; ++ total = stime + curr->utime; ++ ++ /* ++ * Tick based cputime accounting depend on random scheduling ++ * timeslices of a task to be interrupted or not by the timer. ++ * Depending on these circumstances, the number of these interrupts ++ * may be over or under-optimistic, matching the real user and system ++ * cputime with a variable precision. ++ * ++ * Fix this by scaling these tick based values against the total ++ * runtime accounted by the CFS scheduler. ++ */ ++ rtime = nsecs_to_cputime(curr->sum_exec_runtime); ++ ++ /* ++ * Update userspace visible utime/stime values only if actual execution ++ * time is bigger than already exported. Note that can happen, that we ++ * provided bigger values due to scaling inaccuracy on big numbers. ++ */ ++ if (prev->stime + prev->utime >= rtime) ++ goto out; ++ ++ if (total) { ++ stime = scale_stime((__force u64)stime, ++ (__force u64)rtime, (__force u64)total); ++ utime = rtime - stime; ++ } else { ++ stime = rtime; ++ utime = 0; ++ } ++ ++ /* ++ * If the tick based count grows faster than the scheduler one, ++ * the result of the scaling may go backward. ++ * Let's enforce monotonicity. ++ */ ++ prev->stime = max(prev->stime, stime); ++ prev->utime = max(prev->utime, utime); ++ ++out: ++ *ut = prev->utime; ++ *st = prev->stime; ++} ++ ++void task_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st) ++{ ++ struct task_cputime cputime = { ++ .sum_exec_runtime = tsk_seruntime(p), ++ }; ++ ++ task_cputime(p, &cputime.utime, &cputime.stime); ++ cputime_adjust(&cputime, &p->prev_cputime, ut, st); ++} ++ ++/* ++ * Must be called with siglock held. ++ */ ++void thread_group_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st) ++{ ++ struct task_cputime cputime; ++ ++ thread_group_cputime(p, &cputime); ++ cputime_adjust(&cputime, &p->signal->prev_cputime, ut, st); ++} ++#endif ++ ++void init_idle_bootup_task(struct task_struct *idle) ++{} ++ ++#ifdef CONFIG_SCHED_DEBUG ++void proc_sched_show_task(struct task_struct *p, struct seq_file *m) ++{} ++ ++void proc_sched_set_task(struct task_struct *p) ++{} ++#endif ++ ++#ifdef CONFIG_SMP ++#define SCHED_LOAD_SHIFT (10) ++#define SCHED_LOAD_SCALE (1L << SCHED_LOAD_SHIFT) ++ ++unsigned long default_scale_freq_power(struct sched_domain *sd, int cpu) ++{ ++ return SCHED_LOAD_SCALE; ++} ++ ++unsigned long default_scale_smt_power(struct sched_domain *sd, int cpu) ++{ ++ unsigned long weight = cpumask_weight(sched_domain_span(sd)); ++ unsigned long smt_gain = sd->smt_gain; ++ ++ smt_gain /= weight; ++ ++ return smt_gain; ++} ++#endif +Index: linux-3.12-ck2/include/uapi/linux/sched.h +=================================================================== +--- linux-3.12-ck2.orig/include/uapi/linux/sched.h 2013-12-03 20:12:21.186148542 +1100 ++++ linux-3.12-ck2/include/uapi/linux/sched.h 2013-12-03 20:12:21.173148705 +1100 +@@ -37,8 +37,15 @@ + #define SCHED_FIFO 1 + #define SCHED_RR 2 + #define SCHED_BATCH 3 +-/* SCHED_ISO: reserved but not implemented yet */ ++/* SCHED_ISO: Implemented on BFS only */ + #define SCHED_IDLE 5 ++#ifdef CONFIG_SCHED_BFS ++#define SCHED_ISO 4 ++#define SCHED_IDLEPRIO SCHED_IDLE ++#define SCHED_MAX (SCHED_IDLEPRIO) ++#define SCHED_RANGE(policy) ((policy) <= SCHED_MAX) ++#endif ++ + /* Can be ORed in to make sure the process is reverted back to SCHED_NORMAL on fork */ + #define SCHED_RESET_ON_FORK 0x40000000 + +Index: linux-3.12-ck2/include/linux/sched/rt.h +=================================================================== +--- linux-3.12-ck2.orig/include/linux/sched/rt.h 2013-12-03 20:12:21.186148542 +1100 ++++ linux-3.12-ck2/include/linux/sched/rt.h 2013-12-03 20:12:21.173148705 +1100 +@@ -14,11 +14,24 @@ + * MAX_RT_PRIO must not be smaller than MAX_USER_RT_PRIO. + */ + ++#ifdef CONFIG_SCHED_BFS ++#define MAX_USER_RT_PRIO 100 ++#define MAX_RT_PRIO (MAX_USER_RT_PRIO + 1) ++#define DEFAULT_PRIO (MAX_RT_PRIO + 20) ++ ++#define PRIO_RANGE (40) ++#define MAX_PRIO (MAX_RT_PRIO + PRIO_RANGE) ++#define ISO_PRIO (MAX_RT_PRIO) ++#define NORMAL_PRIO (MAX_RT_PRIO + 1) ++#define IDLE_PRIO (MAX_RT_PRIO + 2) ++#define PRIO_LIMIT ((IDLE_PRIO) + 1) ++#else /* CONFIG_SCHED_BFS */ + #define MAX_USER_RT_PRIO 100 + #define MAX_RT_PRIO MAX_USER_RT_PRIO + + #define MAX_PRIO (MAX_RT_PRIO + 40) + #define DEFAULT_PRIO (MAX_RT_PRIO + 20) ++#endif /* CONFIG_SCHED_BFS */ + + static inline int rt_prio(int prio) + { +Index: linux-3.12-ck2/kernel/stop_machine.c +=================================================================== +--- linux-3.12-ck2.orig/kernel/stop_machine.c 2013-12-03 20:12:21.186148542 +1100 ++++ linux-3.12-ck2/kernel/stop_machine.c 2013-12-03 20:12:21.174148692 +1100 +@@ -40,7 +40,8 @@ struct cpu_stopper { + }; + + static DEFINE_PER_CPU(struct cpu_stopper, cpu_stopper); +-static DEFINE_PER_CPU(struct task_struct *, cpu_stopper_task); ++DEFINE_PER_CPU(struct task_struct *, cpu_stopper_task); ++ + static bool stop_machine_initialized = false; + + static void cpu_stop_init_done(struct cpu_stop_done *done, unsigned int nr_todo) +Index: linux-3.12-ck2/drivers/cpufreq/cpufreq_conservative.c +=================================================================== +--- linux-3.12-ck2.orig/drivers/cpufreq/cpufreq_conservative.c 2013-12-03 20:12:21.186148542 +1100 ++++ linux-3.12-ck2/drivers/cpufreq/cpufreq_conservative.c 2013-12-03 20:12:21.174148692 +1100 +@@ -15,8 +15,8 @@ + #include "cpufreq_governor.h" + + /* Conservative governor macros */ +-#define DEF_FREQUENCY_UP_THRESHOLD (80) +-#define DEF_FREQUENCY_DOWN_THRESHOLD (20) ++#define DEF_FREQUENCY_UP_THRESHOLD (63) ++#define DEF_FREQUENCY_DOWN_THRESHOLD (26) + #define DEF_FREQUENCY_STEP (5) + #define DEF_SAMPLING_DOWN_FACTOR (1) + #define MAX_SAMPLING_DOWN_FACTOR (10) +Index: linux-3.12-ck2/kernel/time/Kconfig +=================================================================== +--- linux-3.12-ck2.orig/kernel/time/Kconfig 2013-12-03 20:12:21.186148542 +1100 ++++ linux-3.12-ck2/kernel/time/Kconfig 2013-12-03 20:12:21.175148680 +1100 +@@ -94,7 +94,7 @@ config NO_HZ_IDLE + config NO_HZ_FULL + bool "Full dynticks system (tickless)" + # NO_HZ_COMMON dependency +- depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS ++ depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS && !SCHED_BFS + # We need at least one periodic CPU for timekeeping + depends on SMP + # RCU_USER_QS dependency +Index: linux-3.12-ck2/kernel/sched/Makefile +=================================================================== +--- linux-3.12-ck2.orig/kernel/sched/Makefile 2013-12-03 20:12:21.186148542 +1100 ++++ linux-3.12-ck2/kernel/sched/Makefile 2013-12-03 20:12:21.176148667 +1100 +@@ -11,9 +11,13 @@ ifneq ($(CONFIG_SCHED_OMIT_FRAME_POINTER + CFLAGS_core.o := $(PROFILING) -fno-omit-frame-pointer + endif + ++ifdef CONFIG_SCHED_BFS ++obj-y += bfs.o clock.o ++else + obj-y += core.o proc.o clock.o cputime.o idle_task.o fair.o rt.o stop_task.o +-obj-$(CONFIG_SMP) += cpupri.o + obj-$(CONFIG_SCHED_AUTOGROUP) += auto_group.o +-obj-$(CONFIG_SCHEDSTATS) += stats.o + obj-$(CONFIG_SCHED_DEBUG) += debug.o + obj-$(CONFIG_CGROUP_CPUACCT) += cpuacct.o ++endif ++obj-$(CONFIG_SMP) += cpupri.o ++obj-$(CONFIG_SCHEDSTATS) += stats.o +Index: linux-3.12-ck2/kernel/sched/bfs_sched.h +=================================================================== +--- /dev/null 1970-01-01 00:00:00.000000000 +0000 ++++ linux-3.12-ck2/kernel/sched/bfs_sched.h 2013-12-03 20:12:21.176148667 +1100 +@@ -0,0 +1,116 @@ ++#include ++ ++#ifndef BFS_SCHED_H ++#define BFS_SCHED_H ++ ++/* ++ * This is the main, per-CPU runqueue data structure. ++ * This data should only be modified by the local cpu. ++ */ ++struct rq { ++ struct task_struct *curr, *idle, *stop; ++ struct mm_struct *prev_mm; ++ ++ /* Stored data about rq->curr to work outside grq lock */ ++ u64 rq_deadline; ++ unsigned int rq_policy; ++ int rq_time_slice; ++ u64 rq_last_ran; ++ int rq_prio; ++ bool rq_running; /* There is a task running */ ++ ++ /* Accurate timekeeping data */ ++ u64 timekeep_clock; ++ unsigned long user_pc, nice_pc, irq_pc, softirq_pc, system_pc, ++ iowait_pc, idle_pc; ++ atomic_t nr_iowait; ++ ++#ifdef CONFIG_SMP ++ int cpu; /* cpu of this runqueue */ ++ bool online; ++ bool scaling; /* This CPU is managed by a scaling CPU freq governor */ ++ struct task_struct *sticky_task; ++ ++ struct root_domain *rd; ++ struct sched_domain *sd; ++ int *cpu_locality; /* CPU relative cache distance */ ++#ifdef CONFIG_SCHED_SMT ++ bool (*siblings_idle)(int cpu); ++ /* See if all smt siblings are idle */ ++ cpumask_t smt_siblings; ++#endif /* CONFIG_SCHED_SMT */ ++#ifdef CONFIG_SCHED_MC ++ bool (*cache_idle)(int cpu); ++ /* See if all cache siblings are idle */ ++ cpumask_t cache_siblings; ++#endif /* CONFIG_SCHED_MC */ ++ u64 last_niffy; /* Last time this RQ updated grq.niffies */ ++#endif /* CONFIG_SMP */ ++#ifdef CONFIG_IRQ_TIME_ACCOUNTING ++ u64 prev_irq_time; ++#endif /* CONFIG_IRQ_TIME_ACCOUNTING */ ++#ifdef CONFIG_PARAVIRT ++ u64 prev_steal_time; ++#endif /* CONFIG_PARAVIRT */ ++#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING ++ u64 prev_steal_time_rq; ++#endif /* CONFIG_PARAVIRT_TIME_ACCOUNTING */ ++ ++ u64 clock, old_clock, last_tick; ++ u64 clock_task; ++ bool dither; ++ ++#ifdef CONFIG_SCHEDSTATS ++ ++ /* latency stats */ ++ struct sched_info rq_sched_info; ++ unsigned long long rq_cpu_time; ++ /* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */ ++ ++ /* sys_sched_yield() stats */ ++ unsigned int yld_count; ++ ++ /* schedule() stats */ ++ unsigned int sched_switch; ++ unsigned int sched_count; ++ unsigned int sched_goidle; ++ ++ /* try_to_wake_up() stats */ ++ unsigned int ttwu_count; ++ unsigned int ttwu_local; ++#endif /* CONFIG_SCHEDSTATS */ ++ ++#ifdef CONFIG_SMP ++ struct llist_head wake_list; ++#endif ++}; ++ ++#ifdef CONFIG_SMP ++struct rq *cpu_rq(int cpu); ++#endif ++ ++static inline u64 rq_clock(struct rq *rq) ++{ ++ return rq->clock; ++} ++ ++static inline u64 rq_clock_task(struct rq *rq) ++{ ++ return rq->clock_task; ++} ++ ++#define rcu_dereference_check_sched_domain(p) \ ++ rcu_dereference_check((p), \ ++ lockdep_is_held(&sched_domains_mutex)) ++ ++/* ++ * The domain tree (rq->sd) is protected by RCU's quiescent state transition. ++ * See detach_destroy_domains: synchronize_sched for details. ++ * ++ * The domain tree of any CPU may only be accessed from within ++ * preempt-disabled sections. ++ */ ++#define for_each_domain(cpu, __sd) \ ++ for (__sd = rcu_dereference_check_sched_domain(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent) ++ ++#endif +Index: linux-3.12-ck2/kernel/sched/stats.c +=================================================================== +--- linux-3.12-ck2.orig/kernel/sched/stats.c 2013-12-03 20:12:21.186148542 +1100 ++++ linux-3.12-ck2/kernel/sched/stats.c 2013-12-03 20:12:21.176148667 +1100 +@@ -4,7 +4,11 @@ + #include + #include + ++#ifndef CONFIG_SCHED_BFS + #include "sched.h" ++#else ++#include "bfs_sched.h" ++#endif + + /* + * bump this up when changing the output format or the meaning of an existing diff --git a/patches_disabled/ck2-version.patch b/patches_disabled/ck2-version.patch new file mode 100644 index 0000000..2bf52b5 --- /dev/null +++ b/patches_disabled/ck2-version.patch @@ -0,0 +1,24 @@ +Add -ck version in inconspicuous place where it will merge relatively easily +with later kernel versions. + +-ck + +--- + Makefile | 4 ++++ + 1 file changed, 4 insertions(+) + +Index: linux-3.12-ck2/Makefile +=================================================================== +--- linux-3.12-ck2.orig/Makefile 2013-12-03 20:12:24.295109675 +1100 ++++ linux-3.12-ck2/Makefile 2013-12-03 20:12:24.285109800 +1100 +@@ -10,6 +10,10 @@ NAME = One Giant Leap for Frogkind + # Comments in this file are targeted only to the developer, do not + # expect to learn how to build the kernel reading this file. + ++CKVERSION = -ck2 ++CKNAME = BFS Powered ++EXTRAVERSION := $(EXTRAVERSION)$(CKVERSION) ++ + # Do not: + # o use make's built-in rules and variables + # (this increases performance and avoids hard-to-debug behaviour); diff --git a/patches_disabled/hz-default_1000.patch b/patches_disabled/hz-default_1000.patch new file mode 100644 index 0000000..e540547 --- /dev/null +++ b/patches_disabled/hz-default_1000.patch @@ -0,0 +1,21 @@ +Set default HZ to 1000 which is what most desktop users should still be using. + +-ck + +--- + kernel/Kconfig.hz | 2 +- + 1 file changed, 1 insertion(+), 1 deletion(-) + +Index: linux-3.12-ck2/kernel/Kconfig.hz +=================================================================== +--- linux-3.12-ck2.orig/kernel/Kconfig.hz 2013-12-03 20:12:23.401120851 +1100 ++++ linux-3.12-ck2/kernel/Kconfig.hz 2013-12-03 20:12:23.390120989 +1100 +@@ -4,7 +4,7 @@ + + choice + prompt "Timer frequency" +- default HZ_250 ++ default HZ_1000 + help + Allows the configuration of the timer frequency. It is customary + to have the timer interrupt run at 1000 Hz but 100 Hz may be more diff --git a/patches_disabled/hz-no_default_250.patch b/patches_disabled/hz-no_default_250.patch new file mode 100644 index 0000000..196bb73 --- /dev/null +++ b/patches_disabled/hz-no_default_250.patch @@ -0,0 +1,53 @@ +Make 250HZ not be the default to discourage desktop users from choosing this +option since 1000 will provide better latencies with only miniscule amounts +of extra overhead and power consumption. + +-ck + +--- + kernel/Kconfig.hz | 17 ++++++++++------- + 1 file changed, 10 insertions(+), 7 deletions(-) + +Index: linux-3.12-ck2/kernel/Kconfig.hz +=================================================================== +--- linux-3.12-ck2.orig/kernel/Kconfig.hz 2013-12-03 20:12:22.956126414 +1100 ++++ linux-3.12-ck2/kernel/Kconfig.hz 2013-12-03 20:12:22.946126539 +1100 +@@ -23,13 +23,14 @@ choice + with lots of processors that may show reduced performance if + too many timer interrupts are occurring. + +- config HZ_250 ++ config HZ_250_NODEFAULT + bool "250 HZ" + help +- 250 Hz is a good compromise choice allowing server performance +- while also showing good interactive responsiveness even +- on SMP and NUMA systems. If you are going to be using NTSC video +- or multimedia, selected 300Hz instead. ++ 250 HZ is a lousy compromise choice allowing server interactivity ++ while also showing desktop throughput and no extra power saving on ++ laptops. No good for anything. ++ ++ Recommend 100 or 1000 instead. + + config HZ_300 + bool "300 HZ" +@@ -43,14 +44,16 @@ choice + bool "1000 HZ" + help + 1000 Hz is the preferred choice for desktop systems and other +- systems requiring fast interactive responses to events. ++ systems requiring fast interactive responses to events. Laptops ++ can also benefit from this choice without sacrificing battery life ++ if dynticks is also enabled. + + endchoice + + config HZ + int + default 100 if HZ_100 +- default 250 if HZ_250 ++ default 250 if HZ_250_NODEFAULT + default 300 if HZ_300 + default 1000 if HZ_1000 + diff --git a/patches_disabled/kconfig-expose_vmsplit_option.patch b/patches_disabled/kconfig-expose_vmsplit_option.patch new file mode 100644 index 0000000..1372120 --- /dev/null +++ b/patches_disabled/kconfig-expose_vmsplit_option.patch @@ -0,0 +1,46 @@ +The options to alter the vmsplit to enable more lowmem are hidden behind the +expert option. Make it more exposed for -ck users and make the help menu +more explicit about what each option means. + +-ck + +--- + arch/x86/Kconfig | 12 ++++++------ + 1 file changed, 6 insertions(+), 6 deletions(-) + +Index: linux-3.12-ck2/arch/x86/Kconfig +=================================================================== +--- linux-3.12-ck2.orig/arch/x86/Kconfig 2013-12-03 20:12:23.848115263 +1100 ++++ linux-3.12-ck2/arch/x86/Kconfig 2013-12-03 20:12:23.838115388 +1100 +@@ -1175,7 +1175,7 @@ config HIGHMEM64G + endchoice + + choice +- prompt "Memory split" if EXPERT ++ prompt "Memory split" + default VMSPLIT_3G + depends on X86_32 + ---help--- +@@ -1195,17 +1195,17 @@ choice + option alone! + + config VMSPLIT_3G +- bool "3G/1G user/kernel split" ++ bool "Default 896MB lowmem (3G/1G user/kernel split)" + config VMSPLIT_3G_OPT + depends on !X86_PAE +- bool "3G/1G user/kernel split (for full 1G low memory)" ++ bool "1GB lowmem (3G/1G user/kernel split)" + config VMSPLIT_2G +- bool "2G/2G user/kernel split" ++ bool "2GB lowmem (2G/2G user/kernel split)" + config VMSPLIT_2G_OPT + depends on !X86_PAE +- bool "2G/2G user/kernel split (for full 2G low memory)" ++ bool "2GB lowmem (2G/2G user/kernel split)" + config VMSPLIT_1G +- bool "1G/3G user/kernel split" ++ bool "3GB lowmem (1G/3G user/kernel split)" + endchoice + + config PAGE_OFFSET diff --git a/patches_disabled/preempt-desktop-tune.patch b/patches_disabled/preempt-desktop-tune.patch new file mode 100644 index 0000000..a654a9b --- /dev/null +++ b/patches_disabled/preempt-desktop-tune.patch @@ -0,0 +1,40 @@ +Enable preempt by default and make people steer away from voluntary. + +-ck + +--- + kernel/Kconfig.preempt | 7 ++++--- + 1 file changed, 4 insertions(+), 3 deletions(-) + +Index: linux-3.12-ck2/kernel/Kconfig.preempt +=================================================================== +--- linux-3.12-ck2.orig/kernel/Kconfig.preempt 2013-12-03 20:12:22.511131977 +1100 ++++ linux-3.12-ck2/kernel/Kconfig.preempt 2013-12-03 20:12:22.500132115 +1100 +@@ -1,7 +1,7 @@ + + choice + prompt "Preemption Model" +- default PREEMPT_NONE ++ default PREEMPT + + config PREEMPT_NONE + bool "No Forced Preemption (Server)" +@@ -17,7 +17,7 @@ config PREEMPT_NONE + latencies. + + config PREEMPT_VOLUNTARY +- bool "Voluntary Kernel Preemption (Desktop)" ++ bool "Voluntary Kernel Preemption (Nothing)" + help + This option reduces the latency of the kernel by adding more + "explicit preemption points" to the kernel code. These new +@@ -31,7 +31,8 @@ config PREEMPT_VOLUNTARY + applications to run more 'smoothly' even when the system is + under load. + +- Select this if you are building a kernel for a desktop system. ++ Select this for no system in particular (choose Preemptible ++ instead on a desktop if you know what's good for you). + + config PREEMPT + bool "Preemptible Kernel (Low-Latency Desktop)" diff --git a/patches_disabled/uksm-0.1.2.2-for-v3.12.patch b/patches_disabled/uksm-0.1.2.2-for-v3.12.patch new file mode 100644 index 0000000..7378ddd --- /dev/null +++ b/patches_disabled/uksm-0.1.2.2-for-v3.12.patch @@ -0,0 +1,7064 @@ +diff --git a/Documentation/vm/00-INDEX b/Documentation/vm/00-INDEX +index 5481c8b..7141876 100644 +--- a/Documentation/vm/00-INDEX ++++ b/Documentation/vm/00-INDEX +@@ -14,6 +14,8 @@ hwpoison.txt + - explains what hwpoison is + ksm.txt + - how to use the Kernel Samepage Merging feature. ++uksm.txt ++ - Introduction to Ultra KSM + locking + - info on how locking and synchronization is done in the Linux vm code. + map_hugetlb.c +diff --git a/Documentation/vm/uksm.txt b/Documentation/vm/uksm.txt +new file mode 100644 +index 0000000..9b2cb51 +--- /dev/null ++++ b/Documentation/vm/uksm.txt +@@ -0,0 +1,57 @@ ++The Ultra Kernel Samepage Merging feature ++---------------------------------------------- ++/* ++ * Ultra KSM. Copyright (C) 2011-2012 Nai Xia ++ * ++ * This is an improvement upon KSM. Some basic data structures and routines ++ * are borrowed from ksm.c . ++ * ++ * Its new features: ++ * 1. Full system scan: ++ * It automatically scans all user processes' anonymous VMAs. Kernel-user ++ * interaction to submit a memory area to KSM is no longer needed. ++ * ++ * 2. Rich area detection: ++ * It automatically detects rich areas containing abundant duplicated ++ * pages based. Rich areas are given a full scan speed. Poor areas are ++ * sampled at a reasonable speed with very low CPU consumption. ++ * ++ * 3. Ultra Per-page scan speed improvement: ++ * A new hash algorithm is proposed. As a result, on a machine with ++ * Core(TM)2 Quad Q9300 CPU in 32-bit mode and 800MHZ DDR2 main memory, it ++ * can scan memory areas that does not contain duplicated pages at speed of ++ * 627MB/sec ~ 2445MB/sec and can merge duplicated areas at speed of ++ * 477MB/sec ~ 923MB/sec. ++ * ++ * 4. Thrashing area avoidance: ++ * Thrashing area(an VMA that has frequent Ksm page break-out) can be ++ * filtered out. My benchmark shows it's more efficient than KSM's per-page ++ * hash value based volatile page detection. ++ * ++ * ++ * 5. Misc changes upon KSM: ++ * * It has a fully x86-opitmized memcmp dedicated for 4-byte-aligned page ++ * comparison. It's much faster than default C version on x86. ++ * * rmap_item now has an struct *page member to loosely cache a ++ * address-->page mapping, which reduces too much time-costly ++ * follow_page(). ++ * * The VMA creation/exit procedures are hooked to let the Ultra KSM know. ++ * * try_to_merge_two_pages() now can revert a pte if it fails. No break_ ++ * ksm is needed for this case. ++ * ++ * 6. Full Zero Page consideration(contributed by Figo Zhang) ++ * Now uksmd consider full zero pages as special pages and merge them to an ++ * special unswappable uksm zero page. ++ */ ++ ++ChangeLog: ++ ++2012-05-05 The creation of this Doc ++2012-05-08 UKSM 0.1.1.1 libc crash bug fix, api clean up, doc clean up. ++2012-05-28 UKSM 0.1.1.2 bug fix release ++2012-06-26 UKSM 0.1.2-beta1 first beta release for 0.1.2 ++2012-07-2 UKSM 0.1.2-beta2 ++2012-07-10 UKSM 0.1.2-beta3 ++2012-07-26 UKSM 0.1.2 Fine grained speed control, more scan optimization. ++2012-10-13 UKSM 0.1.2.1 Bug fixes. ++2012-12-31 UKSM 0.1.2.2 Minor bug fixes +diff --git a/fs/exec.c b/fs/exec.c +index 8875dd1..4b86536 100644 +--- a/fs/exec.c ++++ b/fs/exec.c +@@ -19,7 +19,7 @@ + * current->executable is only used by the procfs. This allows a dispatch + * table to check for several different types of binary formats. We keep + * trying until we recognize the file or we run out of supported binary +- * formats. ++ * formats. + */ + + #include +@@ -55,6 +55,7 @@ + #include + #include + #include ++#include + + #include + #include +@@ -1143,7 +1144,7 @@ void setup_new_exec(struct linux_binprm * bprm) + group */ + + current->self_exec_id++; +- ++ + flush_signal_handlers(current, 0); + do_close_on_exec(current->files); + } +@@ -1269,8 +1270,8 @@ static int check_unsafe_exec(struct linux_binprm *bprm) + return res; + } + +-/* +- * Fill the binprm structure from the inode. ++/* ++ * Fill the binprm structure from the inode. + * Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes + * + * This may be called multiple times for binary chains (scripts for example). +diff --git a/fs/proc/meminfo.c b/fs/proc/meminfo.c +index 59d85d6..948cab28 100644 +--- a/fs/proc/meminfo.c ++++ b/fs/proc/meminfo.c +@@ -88,6 +88,9 @@ static int meminfo_proc_show(struct seq_file *m, void *v) + "SUnreclaim: %8lu kB\n" + "KernelStack: %8lu kB\n" + "PageTables: %8lu kB\n" ++#ifdef CONFIG_UKSM ++ "KsmZeroPages: %8lu kB\n" ++#endif + #ifdef CONFIG_QUICKLIST + "Quicklists: %8lu kB\n" + #endif +@@ -141,6 +144,9 @@ static int meminfo_proc_show(struct seq_file *m, void *v) + K(global_page_state(NR_SLAB_UNRECLAIMABLE)), + global_page_state(NR_KERNEL_STACK) * THREAD_SIZE / 1024, + K(global_page_state(NR_PAGETABLE)), ++#ifdef CONFIG_UKSM ++ K(global_page_state(NR_UKSM_ZERO_PAGES)), ++#endif + #ifdef CONFIG_QUICKLIST + K(quicklist_total_size()), + #endif +diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h +index f330d28..0bc3f46 100644 +--- a/include/asm-generic/pgtable.h ++++ b/include/asm-generic/pgtable.h +@@ -502,12 +502,25 @@ extern void untrack_pfn(struct vm_area_struct *vma, unsigned long pfn, + unsigned long size); + #endif + ++#ifdef CONFIG_UKSM ++static inline int is_uksm_zero_pfn(unsigned long pfn) ++{ ++ extern unsigned long uksm_zero_pfn; ++ return pfn == uksm_zero_pfn; ++} ++#else ++static inline int is_uksm_zero_pfn(unsigned long pfn) ++{ ++ return 0; ++} ++#endif ++ + #ifdef __HAVE_COLOR_ZERO_PAGE + static inline int is_zero_pfn(unsigned long pfn) + { + extern unsigned long zero_pfn; + unsigned long offset_from_zero_pfn = pfn - zero_pfn; +- return offset_from_zero_pfn <= (zero_page_mask >> PAGE_SHIFT); ++ return offset_from_zero_pfn <= (zero_page_mask >> PAGE_SHIFT) || is_uksm_zero_pfn(pfn); + } + + #define my_zero_pfn(addr) page_to_pfn(ZERO_PAGE(addr)) +@@ -516,7 +529,7 @@ static inline int is_zero_pfn(unsigned long pfn) + static inline int is_zero_pfn(unsigned long pfn) + { + extern unsigned long zero_pfn; +- return pfn == zero_pfn; ++ return (pfn == zero_pfn) || (is_uksm_zero_pfn(pfn)); + } + + static inline unsigned long my_zero_pfn(unsigned long addr) +diff --git a/include/linux/ksm.h b/include/linux/ksm.h +index 45c9b6a..c7de7a7 100644 +--- a/include/linux/ksm.h ++++ b/include/linux/ksm.h +@@ -19,21 +19,6 @@ struct mem_cgroup; + #ifdef CONFIG_KSM + int ksm_madvise(struct vm_area_struct *vma, unsigned long start, + unsigned long end, int advice, unsigned long *vm_flags); +-int __ksm_enter(struct mm_struct *mm); +-void __ksm_exit(struct mm_struct *mm); +- +-static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm) +-{ +- if (test_bit(MMF_VM_MERGEABLE, &oldmm->flags)) +- return __ksm_enter(mm); +- return 0; +-} +- +-static inline void ksm_exit(struct mm_struct *mm) +-{ +- if (test_bit(MMF_VM_MERGEABLE, &mm->flags)) +- __ksm_exit(mm); +-} + + /* + * A KSM page is one of those write-protected "shared pages" or "merged pages" +@@ -80,6 +65,33 @@ int rmap_walk_ksm(struct page *page, int (*rmap_one)(struct page *, + struct vm_area_struct *, unsigned long, void *), void *arg); + void ksm_migrate_page(struct page *newpage, struct page *oldpage); + ++#ifdef CONFIG_KSM_LEGACY ++int __ksm_enter(struct mm_struct *mm); ++void __ksm_exit(struct mm_struct *mm); ++static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm) ++{ ++ if (test_bit(MMF_VM_MERGEABLE, &oldmm->flags)) ++ return __ksm_enter(mm); ++ return 0; ++} ++ ++static inline void ksm_exit(struct mm_struct *mm) ++{ ++ if (test_bit(MMF_VM_MERGEABLE, &mm->flags)) ++ __ksm_exit(mm); ++} ++ ++#elif defined(CONFIG_UKSM) ++static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm) ++{ ++ return 0; ++} ++ ++static inline void ksm_exit(struct mm_struct *mm) ++{ ++} ++#endif /* !CONFIG_UKSM */ ++ + #else /* !CONFIG_KSM */ + + static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm) +@@ -132,4 +144,6 @@ static inline void ksm_migrate_page(struct page *newpage, struct page *oldpage) + #endif /* CONFIG_MMU */ + #endif /* !CONFIG_KSM */ + ++#include ++ + #endif /* __LINUX_KSM_H */ +diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h +index d9851ee..ecbb39c 100644 +--- a/include/linux/mm_types.h ++++ b/include/linux/mm_types.h +@@ -289,6 +289,9 @@ struct vm_area_struct { + #ifdef CONFIG_NUMA + struct mempolicy *vm_policy; /* NUMA policy for the VMA */ + #endif ++#ifdef CONFIG_UKSM ++ struct vma_slot *uksm_vma_slot; ++#endif + }; + + struct core_thread { +diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h +index bd791e4..44bb9dd 100644 +--- a/include/linux/mmzone.h ++++ b/include/linux/mmzone.h +@@ -144,6 +144,9 @@ enum zone_stat_item { + #endif + NR_ANON_TRANSPARENT_HUGEPAGES, + NR_FREE_CMA_PAGES, ++#ifdef CONFIG_UKSM ++ NR_UKSM_ZERO_PAGES, ++#endif + NR_VM_ZONE_STAT_ITEMS }; + + /* +@@ -870,7 +873,7 @@ static inline int is_highmem_idx(enum zone_type idx) + } + + /** +- * is_highmem - helper function to quickly check if a struct zone is a ++ * is_highmem - helper function to quickly check if a struct zone is a + * highmem zone or not. This is an attempt to keep references + * to ZONE_{DMA/NORMAL/HIGHMEM/etc} in general code to a minimum. + * @zone - pointer to struct zone variable +diff --git a/include/linux/sradix-tree.h b/include/linux/sradix-tree.h +new file mode 100644 +index 0000000..6780fdb +--- /dev/null ++++ b/include/linux/sradix-tree.h +@@ -0,0 +1,77 @@ ++#ifndef _LINUX_SRADIX_TREE_H ++#define _LINUX_SRADIX_TREE_H ++ ++ ++#define INIT_SRADIX_TREE(root, mask) \ ++do { \ ++ (root)->height = 0; \ ++ (root)->gfp_mask = (mask); \ ++ (root)->rnode = NULL; \ ++} while (0) ++ ++#define ULONG_BITS (sizeof(unsigned long) * 8) ++#define SRADIX_TREE_INDEX_BITS (8 /* CHAR_BIT */ * sizeof(unsigned long)) ++//#define SRADIX_TREE_MAP_SHIFT 6 ++//#define SRADIX_TREE_MAP_SIZE (1UL << SRADIX_TREE_MAP_SHIFT) ++//#define SRADIX_TREE_MAP_MASK (SRADIX_TREE_MAP_SIZE-1) ++ ++struct sradix_tree_node { ++ unsigned int height; /* Height from the bottom */ ++ unsigned int count; ++ unsigned int fulls; /* Number of full sublevel trees */ ++ struct sradix_tree_node *parent; ++ void *stores[0]; ++}; ++ ++/* A simple radix tree implementation */ ++struct sradix_tree_root { ++ unsigned int height; ++ struct sradix_tree_node *rnode; ++ ++ /* Where found to have available empty stores in its sublevels */ ++ struct sradix_tree_node *enter_node; ++ unsigned int shift; ++ unsigned int stores_size; ++ unsigned int mask; ++ unsigned long min; /* The first hole index */ ++ unsigned long num; ++ //unsigned long *height_to_maxindex; ++ ++ /* How the node is allocated and freed. */ ++ struct sradix_tree_node *(*alloc)(void); ++ void (*free)(struct sradix_tree_node *node); ++ ++ /* When a new node is added and removed */ ++ void (*extend)(struct sradix_tree_node *parent, struct sradix_tree_node *child); ++ void (*assign)(struct sradix_tree_node *node, unsigned index, void *item); ++ void (*rm)(struct sradix_tree_node *node, unsigned offset); ++}; ++ ++struct sradix_tree_path { ++ struct sradix_tree_node *node; ++ int offset; ++}; ++ ++static inline ++void init_sradix_tree_root(struct sradix_tree_root *root, unsigned long shift) ++{ ++ root->height = 0; ++ root->rnode = NULL; ++ root->shift = shift; ++ root->stores_size = 1UL << shift; ++ root->mask = root->stores_size - 1; ++} ++ ++ ++extern void *sradix_tree_next(struct sradix_tree_root *root, ++ struct sradix_tree_node *node, unsigned long index, ++ int (*iter)(void *, unsigned long)); ++ ++extern int sradix_tree_enter(struct sradix_tree_root *root, void **item, int num); ++ ++extern void sradix_tree_delete_from_leaf(struct sradix_tree_root *root, ++ struct sradix_tree_node *node, unsigned long index); ++ ++extern void *sradix_tree_lookup(struct sradix_tree_root *root, unsigned long index); ++ ++#endif /* _LINUX_SRADIX_TREE_H */ +diff --git a/include/linux/uksm.h b/include/linux/uksm.h +new file mode 100644 +index 0000000..a644bca +--- /dev/null ++++ b/include/linux/uksm.h +@@ -0,0 +1,146 @@ ++#ifndef __LINUX_UKSM_H ++#define __LINUX_UKSM_H ++/* ++ * Memory merging support. ++ * ++ * This code enables dynamic sharing of identical pages found in different ++ * memory areas, even if they are not shared by fork(). ++ */ ++ ++/* if !CONFIG_UKSM this file should not be compiled at all. */ ++#ifdef CONFIG_UKSM ++ ++#include ++#include ++#include ++#include ++#include ++ ++extern unsigned long zero_pfn __read_mostly; ++extern unsigned long uksm_zero_pfn __read_mostly; ++extern struct page *empty_uksm_zero_page; ++ ++/* must be done before linked to mm */ ++extern void uksm_vma_add_new(struct vm_area_struct *vma); ++extern void uksm_remove_vma(struct vm_area_struct *vma); ++ ++#define UKSM_SLOT_NEED_SORT (1 << 0) ++#define UKSM_SLOT_NEED_RERAND (1 << 1) ++#define UKSM_SLOT_SCANNED (1 << 2) /* It's scanned in this round */ ++#define UKSM_SLOT_FUL_SCANNED (1 << 3) ++#define UKSM_SLOT_IN_UKSM (1 << 4) ++ ++struct vma_slot { ++ struct sradix_tree_node *snode; ++ unsigned long sindex; ++ ++ struct list_head slot_list; ++ unsigned long fully_scanned_round; ++ unsigned long dedup_num; ++ unsigned long pages_scanned; ++ unsigned long last_scanned; ++ unsigned long pages_to_scan; ++ struct scan_rung *rung; ++ struct page **rmap_list_pool; ++ unsigned int *pool_counts; ++ unsigned long pool_size; ++ struct vm_area_struct *vma; ++ struct mm_struct *mm; ++ unsigned long ctime_j; ++ unsigned long pages; ++ unsigned long flags; ++ unsigned long pages_cowed; /* pages cowed this round */ ++ unsigned long pages_merged; /* pages merged this round */ ++ unsigned long pages_bemerged; ++ ++ /* when it has page merged in this eval round */ ++ struct list_head dedup_list; ++}; ++ ++static inline void uksm_unmap_zero_page(pte_t pte) ++{ ++ if (pte_pfn(pte) == uksm_zero_pfn) ++ __dec_zone_page_state(empty_uksm_zero_page, NR_UKSM_ZERO_PAGES); ++} ++ ++static inline void uksm_map_zero_page(pte_t pte) ++{ ++ if (pte_pfn(pte) == uksm_zero_pfn) ++ __inc_zone_page_state(empty_uksm_zero_page, NR_UKSM_ZERO_PAGES); ++} ++ ++static inline void uksm_cow_page(struct vm_area_struct *vma, struct page *page) ++{ ++ if (vma->uksm_vma_slot && PageKsm(page)) ++ vma->uksm_vma_slot->pages_cowed++; ++} ++ ++static inline void uksm_cow_pte(struct vm_area_struct *vma, pte_t pte) ++{ ++ if (vma->uksm_vma_slot && pte_pfn(pte) == uksm_zero_pfn) ++ vma->uksm_vma_slot->pages_cowed++; ++} ++ ++static inline int uksm_flags_can_scan(unsigned long vm_flags) ++{ ++#ifndef VM_SAO ++#define VM_SAO 0 ++#endif ++ return !(vm_flags & (VM_PFNMAP | VM_IO | VM_DONTEXPAND | ++ VM_HUGETLB | VM_NONLINEAR | VM_MIXEDMAP | ++ VM_SHARED | VM_MAYSHARE | VM_GROWSUP | VM_GROWSDOWN | VM_SAO)); ++} ++ ++static inline void uksm_vm_flags_mod(unsigned long *vm_flags_p) ++{ ++ if (uksm_flags_can_scan(*vm_flags_p)) ++ *vm_flags_p |= VM_MERGEABLE; ++} ++ ++/* ++ * Just a wrapper for BUG_ON for where ksm_zeropage must not be. TODO: it will ++ * be removed when uksm zero page patch is stable enough. ++ */ ++static inline void uksm_bugon_zeropage(pte_t pte) ++{ ++ BUG_ON(pte_pfn(pte) == uksm_zero_pfn); ++} ++#else ++static inline void uksm_vma_add_new(struct vm_area_struct *vma) ++{ ++} ++ ++static inline void uksm_remove_vma(struct vm_area_struct *vma) ++{ ++} ++ ++static inline void uksm_unmap_zero_page(pte_t pte) ++{ ++} ++ ++static inline void uksm_map_zero_page(pte_t pte) ++{ ++} ++ ++static inline void uksm_cow_page(struct vm_area_struct *vma, struct page *page) ++{ ++} ++ ++static inline void uksm_cow_pte(struct vm_area_struct *vma, pte_t pte) ++{ ++} ++ ++static inline int uksm_flags_can_scan(unsigned long vm_flags) ++{ ++ return 0; ++} ++ ++static inline void uksm_vm_flags_mod(unsigned long *vm_flags_p) ++{ ++} ++ ++static inline void uksm_bugon_zeropage(pte_t pte) ++{ ++} ++#endif /* !CONFIG_UKSM */ ++#endif /* __LINUX_UKSM_H */ +diff --git a/kernel/fork.c b/kernel/fork.c +index 086fe73..d774585 100644 +--- a/kernel/fork.c ++++ b/kernel/fork.c +@@ -394,7 +394,7 @@ static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm) + goto fail_nomem; + charge = len; + } +- tmp = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); ++ tmp = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); + if (!tmp) + goto fail_nomem; + *tmp = *mpnt; +@@ -449,7 +449,7 @@ static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm) + __vma_link_rb(mm, tmp, rb_link, rb_parent); + rb_link = &tmp->vm_rb.rb_right; + rb_parent = &tmp->vm_rb; +- ++ uksm_vma_add_new(tmp); + mm->map_count++; + retval = copy_page_range(mm, oldmm, mpnt); + +diff --git a/lib/Makefile b/lib/Makefile +index f3bb2cb..f42bf2c 100644 +--- a/lib/Makefile ++++ b/lib/Makefile +@@ -8,7 +8,7 @@ KBUILD_CFLAGS = $(subst -pg,,$(ORIG_CFLAGS)) + endif + + lib-y := ctype.o string.o vsprintf.o cmdline.o \ +- rbtree.o radix-tree.o dump_stack.o timerqueue.o\ ++ rbtree.o radix-tree.o sradix-tree.o dump_stack.o timerqueue.o\ + idr.o int_sqrt.o extable.o \ + sha1.o md5.o irq_regs.o reciprocal_div.o argv_split.o \ + proportions.o flex_proportions.o prio_heap.o ratelimit.o show_mem.o \ +diff --git a/lib/sradix-tree.c b/lib/sradix-tree.c +new file mode 100644 +index 0000000..8d06329 +--- /dev/null ++++ b/lib/sradix-tree.c +@@ -0,0 +1,476 @@ ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++ ++static inline int sradix_node_full(struct sradix_tree_root *root, struct sradix_tree_node *node) ++{ ++ return node->fulls == root->stores_size || ++ (node->height == 1 && node->count == root->stores_size); ++} ++ ++/* ++ * Extend a sradix tree so it can store key @index. ++ */ ++static int sradix_tree_extend(struct sradix_tree_root *root, unsigned long index) ++{ ++ struct sradix_tree_node *node; ++ unsigned int height; ++ ++ if (unlikely(root->rnode == NULL)) { ++ if (!(node = root->alloc())) ++ return -ENOMEM; ++ ++ node->height = 1; ++ root->rnode = node; ++ root->height = 1; ++ } ++ ++ /* Figure out what the height should be. */ ++ height = root->height; ++ index >>= root->shift * height; ++ ++ while (index) { ++ index >>= root->shift; ++ height++; ++ } ++ ++ while (height > root->height) { ++ unsigned int newheight; ++ if (!(node = root->alloc())) ++ return -ENOMEM; ++ ++ /* Increase the height. */ ++ node->stores[0] = root->rnode; ++ root->rnode->parent = node; ++ if (root->extend) ++ root->extend(node, root->rnode); ++ ++ newheight = root->height + 1; ++ node->height = newheight; ++ node->count = 1; ++ if (sradix_node_full(root, root->rnode)) ++ node->fulls = 1; ++ ++ root->rnode = node; ++ root->height = newheight; ++ } ++ ++ return 0; ++} ++ ++/* ++ * Search the next item from the current node, that is not NULL ++ * and can satify root->iter(). ++ */ ++void *sradix_tree_next(struct sradix_tree_root *root, ++ struct sradix_tree_node *node, unsigned long index, ++ int (*iter)(void *item, unsigned long height)) ++{ ++ unsigned long offset; ++ void *item; ++ ++ if (unlikely(node == NULL)) { ++ node = root->rnode; ++ for (offset = 0; offset < root->stores_size; offset++) { ++ item = node->stores[offset]; ++ if (item && (!iter || iter(item, node->height))) ++ break; ++ } ++ ++ if (unlikely(offset >= root->stores_size)) ++ return NULL; ++ ++ if (node->height == 1) ++ return item; ++ else ++ goto go_down; ++ } ++ ++ while (node) { ++ offset = (index & root->mask) + 1; ++ for (;offset < root->stores_size; offset++) { ++ item = node->stores[offset]; ++ if (item && (!iter || iter(item, node->height))) ++ break; ++ } ++ ++ if (offset < root->stores_size) ++ break; ++ ++ node = node->parent; ++ index >>= root->shift; ++ } ++ ++ if (!node) ++ return NULL; ++ ++ while (node->height > 1) { ++go_down: ++ node = item; ++ for (offset = 0; offset < root->stores_size; offset++) { ++ item = node->stores[offset]; ++ if (item && (!iter || iter(item, node->height))) ++ break; ++ } ++ ++ if (unlikely(offset >= root->stores_size)) ++ return NULL; ++ } ++ ++ BUG_ON(offset > root->stores_size); ++ ++ return item; ++} ++ ++/* ++ * Blindly insert the item to the tree. Typically, we reuse the ++ * first empty store item. ++ */ ++int sradix_tree_enter(struct sradix_tree_root *root, void **item, int num) ++{ ++ unsigned long index; ++ unsigned int height; ++ struct sradix_tree_node *node, *tmp = NULL; ++ int offset, offset_saved; ++ void **store = NULL; ++ int error, i, j, shift; ++ ++go_on: ++ index = root->min; ++ ++ if (root->enter_node && !sradix_node_full(root, root->enter_node)) { ++ node = root->enter_node; ++ BUG_ON((index >> (root->shift * root->height))); ++ } else { ++ node = root->rnode; ++ if (node == NULL || (index >> (root->shift * root->height)) ++ || sradix_node_full(root, node)) { ++ error = sradix_tree_extend(root, index); ++ if (error) ++ return error; ++ ++ node = root->rnode; ++ } ++ } ++ ++ ++ height = node->height; ++ shift = (height - 1) * root->shift; ++ offset = (index >> shift) & root->mask; ++ while (shift > 0) { ++ offset_saved = offset; ++ for (; offset < root->stores_size; offset++) { ++ store = &node->stores[offset]; ++ tmp = *store; ++ ++ if (!tmp || !sradix_node_full(root, tmp)) ++ break; ++ } ++ BUG_ON(offset >= root->stores_size); ++ ++ if (offset != offset_saved) { ++ index += (offset - offset_saved) << shift; ++ index &= ~((1UL << shift) - 1); ++ } ++ ++ if (!tmp) { ++ if (!(tmp = root->alloc())) ++ return -ENOMEM; ++ ++ tmp->height = shift / root->shift; ++ *store = tmp; ++ tmp->parent = node; ++ node->count++; ++// if (root->extend) ++// root->extend(node, tmp); ++ } ++ ++ node = tmp; ++ shift -= root->shift; ++ offset = (index >> shift) & root->mask; ++ } ++ ++ BUG_ON(node->height != 1); ++ ++ ++ store = &node->stores[offset]; ++ for (i = 0, j = 0; ++ j < root->stores_size - node->count && ++ i < root->stores_size - offset && j < num; i++) { ++ if (!store[i]) { ++ store[i] = item[j]; ++ if (root->assign) ++ root->assign(node, index + i, item[j]); ++ j++; ++ } ++ } ++ ++ node->count += j; ++ root->num += j; ++ num -= j; ++ ++ while (sradix_node_full(root, node)) { ++ node = node->parent; ++ if (!node) ++ break; ++ ++ node->fulls++; ++ } ++ ++ if (unlikely(!node)) { ++ /* All nodes are full */ ++ root->min = 1 << (root->height * root->shift); ++ root->enter_node = NULL; ++ } else { ++ root->min = index + i - 1; ++ root->min |= (1UL << (node->height - 1)) - 1; ++ root->min++; ++ root->enter_node = node; ++ } ++ ++ if (num) { ++ item += j; ++ goto go_on; ++ } ++ ++ return 0; ++} ++ ++ ++/** ++ * sradix_tree_shrink - shrink height of a sradix tree to minimal ++ * @root sradix tree root ++ * ++ */ ++static inline void sradix_tree_shrink(struct sradix_tree_root *root) ++{ ++ /* try to shrink tree height */ ++ while (root->height > 1) { ++ struct sradix_tree_node *to_free = root->rnode; ++ ++ /* ++ * The candidate node has more than one child, or its child ++ * is not at the leftmost store, we cannot shrink. ++ */ ++ if (to_free->count != 1 || !to_free->stores[0]) ++ break; ++ ++ root->rnode = to_free->stores[0]; ++ root->rnode->parent = NULL; ++ root->height--; ++ if (unlikely(root->enter_node == to_free)) { ++ root->enter_node = NULL; ++ } ++ root->free(to_free); ++ } ++} ++ ++/* ++ * Del the item on the known leaf node and index ++ */ ++void sradix_tree_delete_from_leaf(struct sradix_tree_root *root, ++ struct sradix_tree_node *node, unsigned long index) ++{ ++ unsigned int offset; ++ struct sradix_tree_node *start, *end; ++ ++ BUG_ON(node->height != 1); ++ ++ start = node; ++ while (node && !(--node->count)) ++ node = node->parent; ++ ++ end = node; ++ if (!node) { ++ root->rnode = NULL; ++ root->height = 0; ++ root->min = 0; ++ root->num = 0; ++ root->enter_node = NULL; ++ } else { ++ offset = (index >> (root->shift * (node->height - 1))) & root->mask; ++ if (root->rm) ++ root->rm(node, offset); ++ node->stores[offset] = NULL; ++ root->num--; ++ if (root->min > index) { ++ root->min = index; ++ root->enter_node = node; ++ } ++ } ++ ++ if (start != end) { ++ do { ++ node = start; ++ start = start->parent; ++ if (unlikely(root->enter_node == node)) ++ root->enter_node = end; ++ root->free(node); ++ } while (start != end); ++ ++ /* ++ * Note that shrink may free "end", so enter_node still need to ++ * be checked inside. ++ */ ++ sradix_tree_shrink(root); ++ } else if (node->count == root->stores_size - 1) { ++ /* It WAS a full leaf node. Update the ancestors */ ++ node = node->parent; ++ while (node) { ++ node->fulls--; ++ if (node->fulls != root->stores_size - 1) ++ break; ++ ++ node = node->parent; ++ } ++ } ++} ++ ++void *sradix_tree_lookup(struct sradix_tree_root *root, unsigned long index) ++{ ++ unsigned int height, offset; ++ struct sradix_tree_node *node; ++ int shift; ++ ++ node = root->rnode; ++ if (node == NULL || (index >> (root->shift * root->height))) ++ return NULL; ++ ++ height = root->height; ++ shift = (height - 1) * root->shift; ++ ++ do { ++ offset = (index >> shift) & root->mask; ++ node = node->stores[offset]; ++ if (!node) ++ return NULL; ++ ++ shift -= root->shift; ++ } while (shift >= 0); ++ ++ return node; ++} ++ ++/* ++ * Return the item if it exists, otherwise create it in place ++ * and return the created item. ++ */ ++void *sradix_tree_lookup_create(struct sradix_tree_root *root, ++ unsigned long index, void *(*item_alloc)(void)) ++{ ++ unsigned int height, offset; ++ struct sradix_tree_node *node, *tmp; ++ void *item; ++ int shift, error; ++ ++ if (root->rnode == NULL || (index >> (root->shift * root->height))) { ++ if (item_alloc) { ++ error = sradix_tree_extend(root, index); ++ if (error) ++ return NULL; ++ } else { ++ return NULL; ++ } ++ } ++ ++ node = root->rnode; ++ height = root->height; ++ shift = (height - 1) * root->shift; ++ ++ do { ++ offset = (index >> shift) & root->mask; ++ if (!node->stores[offset]) { ++ if (!(tmp = root->alloc())) ++ return NULL; ++ ++ tmp->height = shift / root->shift; ++ node->stores[offset] = tmp; ++ tmp->parent = node; ++ node->count++; ++ node = tmp; ++ } else { ++ node = node->stores[offset]; ++ } ++ ++ shift -= root->shift; ++ } while (shift > 0); ++ ++ BUG_ON(node->height != 1); ++ offset = index & root->mask; ++ if (node->stores[offset]) { ++ return node->stores[offset]; ++ } else if (item_alloc) { ++ if (!(item = item_alloc())) ++ return NULL; ++ ++ node->stores[offset] = item; ++ ++ /* ++ * NOTE: we do NOT call root->assign here, since this item is ++ * newly created by us having no meaning. Caller can call this ++ * if it's necessary to do so. ++ */ ++ ++ node->count++; ++ root->num++; ++ ++ while (sradix_node_full(root, node)) { ++ node = node->parent; ++ if (!node) ++ break; ++ ++ node->fulls++; ++ } ++ ++ if (unlikely(!node)) { ++ /* All nodes are full */ ++ root->min = 1 << (root->height * root->shift); ++ } else { ++ if (root->min == index) { ++ root->min |= (1UL << (node->height - 1)) - 1; ++ root->min++; ++ root->enter_node = node; ++ } ++ } ++ ++ return item; ++ } else { ++ return NULL; ++ } ++ ++} ++ ++int sradix_tree_delete(struct sradix_tree_root *root, unsigned long index) ++{ ++ unsigned int height, offset; ++ struct sradix_tree_node *node; ++ int shift; ++ ++ node = root->rnode; ++ if (node == NULL || (index >> (root->shift * root->height))) ++ return -ENOENT; ++ ++ height = root->height; ++ shift = (height - 1) * root->shift; ++ ++ do { ++ offset = (index >> shift) & root->mask; ++ node = node->stores[offset]; ++ if (!node) ++ return -ENOENT; ++ ++ shift -= root->shift; ++ } while (shift > 0); ++ ++ offset = index & root->mask; ++ if (!node->stores[offset]) ++ return -ENOENT; ++ ++ sradix_tree_delete_from_leaf(root, node, index); ++ ++ return 0; ++} +diff --git a/mm/Kconfig b/mm/Kconfig +index 394838f..daf01b3 100644 +--- a/mm/Kconfig ++++ b/mm/Kconfig +@@ -315,6 +315,32 @@ config KSM + See Documentation/vm/ksm.txt for more information: KSM is inactive + until a program has madvised that an area is MADV_MERGEABLE, and + root has set /sys/kernel/mm/ksm/run to 1 (if CONFIG_SYSFS is set). ++choice ++ prompt "Choose UKSM/KSM strategy" ++ default UKSM ++ depends on KSM ++ help ++ This option allows to select a UKSM/KSM stragety. ++ ++config UKSM ++ bool "Ultra-KSM for page merging" ++ depends on KSM ++ help ++ UKSM is inspired by the Linux kernel project \u2014 KSM(Kernel Same ++ page Merging), but with a fundamentally rewritten core algorithm. With ++ an advanced algorithm, UKSM now can transparently scans all anonymously ++ mapped user space applications with an significantly improved scan speed ++ and CPU efficiency. Since KVM is friendly to KSM, KVM can also benefit from ++ UKSM. Now UKSM has its first stable release and first real world enterprise user. ++ For more information, please goto its project page. ++ (www.kerneldedup.org) ++ ++config KSM_LEGACY ++ bool "Legacy KSM implementation" ++ depends on KSM ++ help ++ The legacy KSM implementation from Redhat. ++endchoice + + config DEFAULT_MMAP_MIN_ADDR + int "Low address space to protect from user allocation" +diff --git a/mm/Makefile b/mm/Makefile +index 305d10a..b5e5920 100644 +--- a/mm/Makefile ++++ b/mm/Makefile +@@ -40,7 +40,8 @@ obj-$(CONFIG_SPARSEMEM) += sparse.o + obj-$(CONFIG_SPARSEMEM_VMEMMAP) += sparse-vmemmap.o + obj-$(CONFIG_SLOB) += slob.o + obj-$(CONFIG_MMU_NOTIFIER) += mmu_notifier.o +-obj-$(CONFIG_KSM) += ksm.o ++obj-$(CONFIG_KSM_LEGACY) += ksm.o ++obj-$(CONFIG_UKSM) += uksm.o + obj-$(CONFIG_PAGE_POISONING) += debug-pagealloc.o + obj-$(CONFIG_SLAB) += slab.o + obj-$(CONFIG_SLUB) += slub.o +diff --git a/mm/memory.c b/mm/memory.c +index d176154..5d30a95 100644 +--- a/mm/memory.c ++++ b/mm/memory.c +@@ -116,6 +116,27 @@ __setup("norandmaps", disable_randmaps); + unsigned long zero_pfn __read_mostly; + unsigned long highest_memmap_pfn __read_mostly; + ++#ifdef CONFIG_UKSM ++unsigned long uksm_zero_pfn __read_mostly; ++struct page *empty_uksm_zero_page; ++ ++static int __init setup_uksm_zero_page(void) ++{ ++ unsigned long addr; ++ addr = __get_free_pages(GFP_KERNEL | __GFP_ZERO, 0); ++ if (!addr) ++ panic("Oh boy, that early out of memory?"); ++ ++ empty_uksm_zero_page = virt_to_page((void *) addr); ++ SetPageReserved(empty_uksm_zero_page); ++ ++ uksm_zero_pfn = page_to_pfn(empty_uksm_zero_page); ++ ++ return 0; ++} ++core_initcall(setup_uksm_zero_page); ++#endif ++ + /* + * CONFIG_MMU architectures set up ZERO_PAGE in their paging_init() + */ +@@ -127,6 +148,7 @@ static int __init init_zero_pfn(void) + core_initcall(init_zero_pfn); + + ++ + #if defined(SPLIT_RSS_COUNTING) + + void sync_mm_rss(struct mm_struct *mm) +@@ -871,6 +893,11 @@ copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, + rss[MM_ANONPAGES]++; + else + rss[MM_FILEPAGES]++; ++ ++ /* Should return NULL in vm_normal_page() */ ++ uksm_bugon_zeropage(pte); ++ } else { ++ uksm_map_zero_page(pte); + } + + out_set_pte: +@@ -1113,8 +1140,10 @@ again: + ptent = ptep_get_and_clear_full(mm, addr, pte, + tlb->fullmm); + tlb_remove_tlb_entry(tlb, pte, addr); +- if (unlikely(!page)) ++ if (unlikely(!page)) { ++ uksm_unmap_zero_page(ptent); + continue; ++ } + if (unlikely(details) && details->nonlinear_vma + && linear_page_index(details->nonlinear_vma, + addr) != page->index) { +@@ -1705,7 +1734,7 @@ long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, + + VM_BUG_ON(!!pages != !!(gup_flags & FOLL_GET)); + +- /* ++ /* + * Require read or write permissions. + * If FOLL_FORCE is set, we only require the "MAY" flags. + */ +@@ -1765,7 +1794,7 @@ long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, + page = vm_normal_page(vma, start, *pte); + if (!page) { + if (!(gup_flags & FOLL_DUMP) && +- is_zero_pfn(pte_pfn(*pte))) ++ (is_zero_pfn(pte_pfn(*pte)))) + page = pte_page(*pte); + else { + pte_unmap(pte); +@@ -2580,8 +2609,10 @@ static inline void cow_user_page(struct page *dst, struct page *src, unsigned lo + clear_page(kaddr); + kunmap_atomic(kaddr); + flush_dcache_page(dst); +- } else ++ } else { + copy_user_highpage(dst, src, va, vma); ++ uksm_cow_page(vma, src); ++ } + } + + /* +@@ -2780,6 +2811,7 @@ gotten: + new_page = alloc_zeroed_user_highpage_movable(vma, address); + if (!new_page) + goto oom; ++ uksm_cow_pte(vma, orig_pte); + } else { + new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address); + if (!new_page) +@@ -2805,8 +2837,11 @@ gotten: + dec_mm_counter_fast(mm, MM_FILEPAGES); + inc_mm_counter_fast(mm, MM_ANONPAGES); + } +- } else ++ uksm_bugon_zeropage(orig_pte); ++ } else { ++ uksm_unmap_zero_page(orig_pte); + inc_mm_counter_fast(mm, MM_ANONPAGES); ++ } + flush_cache_page(vma, address, pte_pfn(orig_pte)); + entry = mk_pte(new_page, vma->vm_page_prot); + entry = maybe_mkwrite(pte_mkdirty(entry), vma); +diff --git a/mm/mmap.c b/mm/mmap.c +index 9d54851..6c8b834 100644 +--- a/mm/mmap.c ++++ b/mm/mmap.c +@@ -36,6 +36,7 @@ + #include + #include + #include ++#include + + #include + #include +@@ -65,7 +66,7 @@ static void unmap_region(struct mm_struct *mm, + * MAP_SHARED r: (no) no r: (yes) yes r: (no) yes r: (no) yes + * w: (no) no w: (no) no w: (yes) yes w: (no) no + * x: (no) no x: (no) yes x: (no) yes x: (yes) yes +- * ++ * + * MAP_PRIVATE r: (no) no r: (yes) yes r: (no) yes r: (no) yes + * w: (no) no w: (no) no w: (copy) copy w: (no) no + * x: (no) no x: (no) yes x: (no) yes x: (yes) yes +@@ -252,6 +253,7 @@ static struct vm_area_struct *remove_vma(struct vm_area_struct *vma) + if (vma->vm_file) + fput(vma->vm_file); + mpol_put(vma_policy(vma)); ++ uksm_remove_vma(vma); + kmem_cache_free(vm_area_cachep, vma); + return next; + } +@@ -707,9 +709,16 @@ int vma_adjust(struct vm_area_struct *vma, unsigned long start, + long adjust_next = 0; + int remove_next = 0; + ++/* ++ * to avoid deadlock, ksm_remove_vma must be done before any spin_lock is ++ * acquired ++ */ ++ uksm_remove_vma(vma); ++ + if (next && !insert) { + struct vm_area_struct *exporter = NULL; + ++ uksm_remove_vma(next); + if (end >= next->vm_end) { + /* + * vma expands, overlapping all the next, and +@@ -803,6 +812,7 @@ again: remove_next = 1 + (end > next->vm_end); + end_changed = true; + } + vma->vm_pgoff = pgoff; ++ + if (adjust_next) { + next->vm_start += adjust_next << PAGE_SHIFT; + next->vm_pgoff += adjust_next; +@@ -873,16 +883,22 @@ again: remove_next = 1 + (end > next->vm_end); + * up the code too much to do both in one go. + */ + next = vma->vm_next; +- if (remove_next == 2) ++ if (remove_next == 2) { ++ uksm_remove_vma(next); + goto again; +- else if (next) ++ } else if (next) { + vma_gap_update(next); +- else ++ } else { + mm->highest_vm_end = end; ++ } ++ } else { ++ if (next && !insert) ++ uksm_vma_add_new(next); + } + if (insert && file) + uprobe_mmap(insert); + ++ uksm_vma_add_new(vma); + validate_mm(mm); + + return 0; +@@ -1249,6 +1265,9 @@ unsigned long do_mmap_pgoff(struct file *file, unsigned long addr, + vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags) | + mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; + ++ /* If uksm is enabled, we add VM_MERGABLE to new VMAs. */ ++ uksm_vm_flags_mod(&vm_flags); ++ + if (flags & MAP_LOCKED) + if (!can_do_mlock()) + return -EPERM; +@@ -1593,6 +1612,7 @@ munmap_back: + if (vm_flags & VM_DENYWRITE) + allow_write_access(file); + file = vma->vm_file; ++ uksm_vma_add_new(vma); + out: + perf_event_mmap(vma); + +@@ -1629,6 +1649,7 @@ unmap_and_free_vma: + unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end); + charged = 0; + free_vma: ++ uksm_remove_vma(vma); + kmem_cache_free(vm_area_cachep, vma); + unacct_error: + if (charged) +@@ -1877,7 +1898,7 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr, + info.align_mask = 0; + return vm_unmapped_area(&info); + } +-#endif ++#endif + + /* + * This mmap-allocator allocates new areas top-down from below the +@@ -2423,6 +2444,8 @@ static int __split_vma(struct mm_struct * mm, struct vm_area_struct * vma, + else + err = vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new); + ++ uksm_vma_add_new(new); ++ + /* Success. */ + if (!err) + return 0; +@@ -2588,6 +2611,7 @@ static unsigned long do_brk(unsigned long addr, unsigned long len) + return addr; + + flags = VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags; ++ uksm_vm_flags_mod(&flags); + + error = get_unmapped_area(NULL, addr, len, 0, MAP_FIXED); + if (error & ~PAGE_MASK) +@@ -2655,6 +2679,7 @@ static unsigned long do_brk(unsigned long addr, unsigned long len) + vma->vm_flags = flags; + vma->vm_page_prot = vm_get_page_prot(flags); + vma_link(mm, vma, prev, rb_link, rb_parent); ++ uksm_vma_add_new(vma); + out: + perf_event_mmap(vma); + mm->total_vm += len >> PAGE_SHIFT; +@@ -2690,6 +2715,12 @@ void exit_mmap(struct mm_struct *mm) + /* mm's last user has gone, and its about to be pulled down */ + mmu_notifier_release(mm); + ++ /* ++ * Taking write lock on mmap_sem does not harm others, ++ * but it's crucial for uksm to avoid races. ++ */ ++ down_write(&mm->mmap_sem); ++ + if (mm->locked_vm) { + vma = mm->mmap; + while (vma) { +@@ -2726,6 +2757,11 @@ void exit_mmap(struct mm_struct *mm) + } + vm_unacct_memory(nr_accounted); + ++ mm->mmap = NULL; ++ mm->mm_rb = RB_ROOT; ++ mm->mmap_cache = NULL; ++ up_write(&mm->mmap_sem); ++ + WARN_ON(mm->nr_ptes > (FIRST_USER_ADDRESS+PMD_SIZE-1)>>PMD_SHIFT); + } + +@@ -2833,6 +2869,7 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, + new_vma->vm_ops->open(new_vma); + vma_link(mm, new_vma, prev, rb_link, rb_parent); + *need_rmap_locks = false; ++ uksm_vma_add_new(new_vma); + } + } + return new_vma; +@@ -2934,10 +2971,10 @@ int install_special_mapping(struct mm_struct *mm, + ret = insert_vm_struct(mm, vma); + if (ret) + goto out; +- + mm->total_vm += len >> PAGE_SHIFT; + + perf_event_mmap(vma); ++ uksm_vma_add_new(vma); + + return 0; + +diff --git a/mm/rmap.c b/mm/rmap.c +index fd3ee7a..6c07ff9 100644 +--- a/mm/rmap.c ++++ b/mm/rmap.c +@@ -970,9 +970,9 @@ void page_move_anon_rmap(struct page *page, + + /** + * __page_set_anon_rmap - set up new anonymous rmap +- * @page: Page to add to rmap ++ * @page: Page to add to rmap + * @vma: VM area to add page to. +- * @address: User virtual address of the mapping ++ * @address: User virtual address of the mapping + * @exclusive: the page is exclusively owned by the current process + */ + static void __page_set_anon_rmap(struct page *page, +diff --git a/mm/uksm.c b/mm/uksm.c +new file mode 100644 +index 0000000..794867a +--- /dev/null ++++ b/mm/uksm.c +@@ -0,0 +1,5640 @@ ++/* ++ * Ultra KSM. Copyright (C) 2011-2012 Nai Xia ++ * ++ * This is an improvement upon KSM. Some basic data structures and routines ++ * are borrowed from ksm.c . ++ * ++ * Its new features: ++ * 1. Full system scan: ++ * It automatically scans all user processes' anonymous VMAs. Kernel-user ++ * interaction to submit a memory area to KSM is no longer needed. ++ * ++ * 2. Rich area detection: ++ * It automatically detects rich areas containing abundant duplicated ++ * pages based. Rich areas are given a full scan speed. Poor areas are ++ * sampled at a reasonable speed with very low CPU consumption. ++ * ++ * 3. Ultra Per-page scan speed improvement: ++ * A new hash algorithm is proposed. As a result, on a machine with ++ * Core(TM)2 Quad Q9300 CPU in 32-bit mode and 800MHZ DDR2 main memory, it ++ * can scan memory areas that does not contain duplicated pages at speed of ++ * 627MB/sec ~ 2445MB/sec and can merge duplicated areas at speed of ++ * 477MB/sec ~ 923MB/sec. ++ * ++ * 4. Thrashing area avoidance: ++ * Thrashing area(an VMA that has frequent Ksm page break-out) can be ++ * filtered out. My benchmark shows it's more efficient than KSM's per-page ++ * hash value based volatile page detection. ++ * ++ * ++ * 5. Misc changes upon KSM: ++ * * It has a fully x86-opitmized memcmp dedicated for 4-byte-aligned page ++ * comparison. It's much faster than default C version on x86. ++ * * rmap_item now has an struct *page member to loosely cache a ++ * address-->page mapping, which reduces too much time-costly ++ * follow_page(). ++ * * The VMA creation/exit procedures are hooked to let the Ultra KSM know. ++ * * try_to_merge_two_pages() now can revert a pte if it fails. No break_ ++ * ksm is needed for this case. ++ * ++ * 6. Full Zero Page consideration(contributed by Figo Zhang) ++ * Now uksmd consider full zero pages as special pages and merge them to an ++ * special unswappable uksm zero page. ++ */ ++ ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++ ++#include ++#include "internal.h" ++ ++#ifdef CONFIG_X86 ++#undef memcmp ++ ++#ifdef CONFIG_X86_32 ++#define memcmp memcmpx86_32 ++/* ++ * Compare 4-byte-aligned address s1 and s2, with length n ++ */ ++int memcmpx86_32(void *s1, void *s2, size_t n) ++{ ++ size_t num = n / 4; ++ register int res; ++ ++ __asm__ __volatile__ ++ ( ++ "testl %3,%3\n\t" ++ "repe; cmpsd\n\t" ++ "je 1f\n\t" ++ "sbbl %0,%0\n\t" ++ "orl $1,%0\n" ++ "1:" ++ : "=&a" (res), "+&S" (s1), "+&D" (s2), "+&c" (num) ++ : "0" (0) ++ : "cc"); ++ ++ return res; ++} ++ ++/* ++ * Check the page is all zero ? ++ */ ++static int is_full_zero(const void *s1, size_t len) ++{ ++ unsigned char same; ++ ++ len /= 4; ++ ++ __asm__ __volatile__ ++ ("repe; scasl;" ++ "sete %0" ++ : "=qm" (same), "+D" (s1), "+c" (len) ++ : "a" (0) ++ : "cc"); ++ ++ return same; ++} ++ ++ ++#elif defined(CONFIG_X86_64) ++#define memcmp memcmpx86_64 ++/* ++ * Compare 8-byte-aligned address s1 and s2, with length n ++ */ ++int memcmpx86_64(void *s1, void *s2, size_t n) ++{ ++ size_t num = n / 8; ++ register int res; ++ ++ __asm__ __volatile__ ++ ( ++ "testq %q3,%q3\n\t" ++ "repe; cmpsq\n\t" ++ "je 1f\n\t" ++ "sbbq %q0,%q0\n\t" ++ "orq $1,%q0\n" ++ "1:" ++ : "=&a" (res), "+&S" (s1), "+&D" (s2), "+&c" (num) ++ : "0" (0) ++ : "cc"); ++ ++ return res; ++} ++ ++static int is_full_zero(const void *s1, size_t len) ++{ ++ unsigned char same; ++ ++ len /= 8; ++ ++ __asm__ __volatile__ ++ ("repe; scasq;" ++ "sete %0" ++ : "=qm" (same), "+D" (s1), "+c" (len) ++ : "a" (0) ++ : "cc"); ++ ++ return same; ++} ++ ++#endif ++#else ++static int is_full_zero(const void *s1, size_t len) ++{ ++ unsigned long *src = s1; ++ int i; ++ ++ len /= sizeof(*src); ++ ++ for (i = 0; i < len; i++) { ++ if (src[i]) ++ return 0; ++ } ++ ++ return 1; ++} ++#endif ++ ++#define U64_MAX (~((u64)0)) ++#define UKSM_RUNG_ROUND_FINISHED (1 << 0) ++#define TIME_RATIO_SCALE 10000 ++ ++#define SLOT_TREE_NODE_SHIFT 8 ++#define SLOT_TREE_NODE_STORE_SIZE (1UL << SLOT_TREE_NODE_SHIFT) ++struct slot_tree_node { ++ unsigned long size; ++ struct sradix_tree_node snode; ++ void *stores[SLOT_TREE_NODE_STORE_SIZE]; ++}; ++ ++static struct kmem_cache *slot_tree_node_cachep; ++ ++static struct sradix_tree_node *slot_tree_node_alloc(void) ++{ ++ struct slot_tree_node *p; ++ p = kmem_cache_zalloc(slot_tree_node_cachep, GFP_KERNEL); ++ if (!p) ++ return NULL; ++ ++ return &p->snode; ++} ++ ++static void slot_tree_node_free(struct sradix_tree_node *node) ++{ ++ struct slot_tree_node *p; ++ ++ p = container_of(node, struct slot_tree_node, snode); ++ kmem_cache_free(slot_tree_node_cachep, p); ++} ++ ++static void slot_tree_node_extend(struct sradix_tree_node *parent, ++ struct sradix_tree_node *child) ++{ ++ struct slot_tree_node *p, *c; ++ ++ p = container_of(parent, struct slot_tree_node, snode); ++ c = container_of(child, struct slot_tree_node, snode); ++ ++ p->size += c->size; ++} ++ ++void slot_tree_node_assign(struct sradix_tree_node *node, ++ unsigned index, void *item) ++{ ++ struct vma_slot *slot = item; ++ struct slot_tree_node *cur; ++ ++ slot->snode = node; ++ slot->sindex = index; ++ ++ while (node) { ++ cur = container_of(node, struct slot_tree_node, snode); ++ cur->size += slot->pages; ++ node = node->parent; ++ } ++} ++ ++void slot_tree_node_rm(struct sradix_tree_node *node, unsigned offset) ++{ ++ struct vma_slot *slot; ++ struct slot_tree_node *cur; ++ unsigned long pages; ++ ++ if (node->height == 1) { ++ slot = node->stores[offset]; ++ pages = slot->pages; ++ } else { ++ cur = container_of(node->stores[offset], ++ struct slot_tree_node, snode); ++ pages = cur->size; ++ } ++ ++ while (node) { ++ cur = container_of(node, struct slot_tree_node, snode); ++ cur->size -= pages; ++ node = node->parent; ++ } ++} ++ ++unsigned long slot_iter_index; ++int slot_iter(void *item, unsigned long height) ++{ ++ struct slot_tree_node *node; ++ struct vma_slot *slot; ++ ++ if (height == 1) { ++ slot = item; ++ if (slot_iter_index < slot->pages) { ++ /*in this one*/ ++ return 1; ++ } else { ++ slot_iter_index -= slot->pages; ++ return 0; ++ } ++ ++ } else { ++ node = container_of(item, struct slot_tree_node, snode); ++ if (slot_iter_index < node->size) { ++ /*in this one*/ ++ return 1; ++ } else { ++ slot_iter_index -= node->size; ++ return 0; ++ } ++ } ++} ++ ++ ++static inline void slot_tree_init_root(struct sradix_tree_root *root) ++{ ++ init_sradix_tree_root(root, SLOT_TREE_NODE_SHIFT); ++ root->alloc = slot_tree_node_alloc; ++ root->free = slot_tree_node_free; ++ root->extend = slot_tree_node_extend; ++ root->assign = slot_tree_node_assign; ++ root->rm = slot_tree_node_rm; ++} ++ ++void slot_tree_init(void) ++{ ++ slot_tree_node_cachep = kmem_cache_create("slot_tree_node", ++ sizeof(struct slot_tree_node), 0, ++ SLAB_PANIC | SLAB_RECLAIM_ACCOUNT, ++ NULL); ++} ++ ++ ++/* Each rung of this ladder is a list of VMAs having a same scan ratio */ ++struct scan_rung { ++ //struct list_head scanned_list; ++ struct sradix_tree_root vma_root; ++ struct sradix_tree_root vma_root2; ++ ++ struct vma_slot *current_scan; ++ unsigned long current_offset; ++ ++ /* ++ * The initial value for current_offset, it should loop over ++ * [0~ step - 1] to let all slot have its chance to be scanned. ++ */ ++ unsigned long offset_init; ++ unsigned long step; /* dynamic step for current_offset */ ++ unsigned int flags; ++ unsigned long pages_to_scan; ++ //unsigned long fully_scanned_slots; ++ /* ++ * a little bit tricky - if cpu_time_ratio > 0, then the value is the ++ * the cpu time ratio it can spend in rung_i for every scan ++ * period. if < 0, then it is the cpu time ratio relative to the ++ * max cpu percentage user specified. Both in unit of ++ * 1/TIME_RATIO_SCALE ++ */ ++ int cpu_ratio; ++ ++ /* ++ * How long it will take for all slots in this rung to be fully ++ * scanned? If it's zero, we don't care about the cover time: ++ * it's fully scanned. ++ */ ++ unsigned int cover_msecs; ++ //unsigned long vma_num; ++ //unsigned long pages; /* Sum of all slot's pages in rung */ ++}; ++ ++/** ++ * node of either the stable or unstale rbtree ++ * ++ */ ++struct tree_node { ++ struct rb_node node; /* link in the main (un)stable rbtree */ ++ struct rb_root sub_root; /* rb_root for sublevel collision rbtree */ ++ u32 hash; ++ unsigned long count; /* TODO: merged with sub_root */ ++ struct list_head all_list; /* all tree nodes in stable/unstable tree */ ++}; ++ ++/** ++ * struct stable_node - node of the stable rbtree ++ * @node: rb node of this ksm page in the stable tree ++ * @hlist: hlist head of rmap_items using this ksm page ++ * @kpfn: page frame number of this ksm page ++ */ ++struct stable_node { ++ struct rb_node node; /* link in sub-rbtree */ ++ struct tree_node *tree_node; /* it's tree node root in stable tree, NULL if it's in hell list */ ++ struct hlist_head hlist; ++ unsigned long kpfn; ++ u32 hash_max; /* if ==0 then it's not been calculated yet */ ++ struct list_head all_list; /* in a list for all stable nodes */ ++}; ++ ++/** ++ * struct node_vma - group rmap_items linked in a same stable ++ * node together. ++ */ ++struct node_vma { ++ union { ++ struct vma_slot *slot; ++ unsigned long key; /* slot is used as key sorted on hlist */ ++ }; ++ struct hlist_node hlist; ++ struct hlist_head rmap_hlist; ++ struct stable_node *head; ++}; ++ ++/** ++ * struct rmap_item - reverse mapping item for virtual addresses ++ * @rmap_list: next rmap_item in mm_slot's singly-linked rmap_list ++ * @anon_vma: pointer to anon_vma for this mm,address, when in stable tree ++ * @mm: the memory structure this rmap_item is pointing into ++ * @address: the virtual address this rmap_item tracks (+ flags in low bits) ++ * @node: rb node of this rmap_item in the unstable tree ++ * @head: pointer to stable_node heading this list in the stable tree ++ * @hlist: link into hlist of rmap_items hanging off that stable_node ++ */ ++struct rmap_item { ++ struct vma_slot *slot; ++ struct page *page; ++ unsigned long address; /* + low bits used for flags below */ ++ unsigned long hash_round; ++ unsigned long entry_index; ++ union { ++ struct {/* when in unstable tree */ ++ struct rb_node node; ++ struct tree_node *tree_node; ++ u32 hash_max; ++ }; ++ struct { /* when in stable tree */ ++ struct node_vma *head; ++ struct hlist_node hlist; ++ struct anon_vma *anon_vma; ++ }; ++ }; ++} __attribute__((aligned(4))); ++ ++struct rmap_list_entry { ++ union { ++ struct rmap_item *item; ++ unsigned long addr; ++ }; ++ /* lowest bit is used for is_addr tag */ ++} __attribute__((aligned(4))); /* 4 aligned to fit in to pages*/ ++ ++ ++/* Basic data structure definition ends */ ++ ++ ++/* ++ * Flags for rmap_item to judge if it's listed in the stable/unstable tree. ++ * The flags use the low bits of rmap_item.address ++ */ ++#define UNSTABLE_FLAG 0x1 ++#define STABLE_FLAG 0x2 ++#define get_rmap_addr(x) ((x)->address & PAGE_MASK) ++ ++/* ++ * rmap_list_entry helpers ++ */ ++#define IS_ADDR_FLAG 1 ++#define is_addr(ptr) ((unsigned long)(ptr) & IS_ADDR_FLAG) ++#define set_is_addr(ptr) ((ptr) |= IS_ADDR_FLAG) ++#define get_clean_addr(ptr) (((ptr) & ~(__typeof__(ptr))IS_ADDR_FLAG)) ++ ++ ++/* ++ * High speed caches for frequently allocated and freed structs ++ */ ++static struct kmem_cache *rmap_item_cache; ++static struct kmem_cache *stable_node_cache; ++static struct kmem_cache *node_vma_cache; ++static struct kmem_cache *vma_slot_cache; ++static struct kmem_cache *tree_node_cache; ++#define UKSM_KMEM_CACHE(__struct, __flags) kmem_cache_create("uksm_"#__struct,\ ++ sizeof(struct __struct), __alignof__(struct __struct),\ ++ (__flags), NULL) ++ ++/* Array of all scan_rung, uksm_scan_ladder[0] having the minimum scan ratio */ ++#define SCAN_LADDER_SIZE 4 ++static struct scan_rung uksm_scan_ladder[SCAN_LADDER_SIZE]; ++ ++/* The evaluation rounds uksmd has finished */ ++static unsigned long long uksm_eval_round = 1; ++ ++/* ++ * we add 1 to this var when we consider we should rebuild the whole ++ * unstable tree. ++ */ ++static unsigned long uksm_hash_round = 1; ++ ++/* ++ * How many times the whole memory is scanned. ++ */ ++static unsigned long long fully_scanned_round = 1; ++ ++/* The total number of virtual pages of all vma slots */ ++static u64 uksm_pages_total; ++ ++/* The number of pages has been scanned since the start up */ ++static u64 uksm_pages_scanned; ++ ++static u64 scanned_virtual_pages; ++ ++/* The number of pages has been scanned since last encode_benefit call */ ++static u64 uksm_pages_scanned_last; ++ ++/* If the scanned number is tooo large, we encode it here */ ++static u64 pages_scanned_stored; ++ ++static unsigned long pages_scanned_base; ++ ++/* The number of nodes in the stable tree */ ++static unsigned long uksm_pages_shared; ++ ++/* The number of page slots additionally sharing those nodes */ ++static unsigned long uksm_pages_sharing; ++ ++/* The number of nodes in the unstable tree */ ++static unsigned long uksm_pages_unshared; ++ ++/* ++ * Milliseconds ksmd should sleep between scans, ++ * >= 100ms to be consistent with ++ * scan_time_to_sleep_msec() ++ */ ++static unsigned int uksm_sleep_jiffies; ++ ++/* The real value for the uksmd next sleep */ ++static unsigned int uksm_sleep_real; ++ ++/* Saved value for user input uksm_sleep_jiffies when it's enlarged */ ++static unsigned int uksm_sleep_saved; ++ ++/* Max percentage of cpu utilization ksmd can take to scan in one batch */ ++static unsigned int uksm_max_cpu_percentage; ++ ++static int uksm_cpu_governor; ++ ++static char *uksm_cpu_governor_str[4] = { "full", "medium", "low", "quiet" }; ++ ++struct uksm_cpu_preset_s { ++ int cpu_ratio[SCAN_LADDER_SIZE]; ++ unsigned int cover_msecs[SCAN_LADDER_SIZE]; ++ unsigned int max_cpu; /* percentage */ ++}; ++ ++struct uksm_cpu_preset_s uksm_cpu_preset[4] = { ++ { {20, 40, -2500, -10000}, {1000, 500, 200, 50}, 95}, ++ { {20, 30, -2500, -10000}, {1000, 500, 400, 100}, 50}, ++ { {10, 20, -5000, -10000}, {1500, 1000, 1000, 250}, 20}, ++ { {10, 20, 40, 75}, {2000, 1000, 1000, 1000}, 1}, ++}; ++ ++/* The default value for uksm_ema_page_time if it's not initialized */ ++#define UKSM_PAGE_TIME_DEFAULT 500 ++ ++/*cost to scan one page by expotional moving average in nsecs */ ++static unsigned long uksm_ema_page_time = UKSM_PAGE_TIME_DEFAULT; ++ ++/* The expotional moving average alpha weight, in percentage. */ ++#define EMA_ALPHA 20 ++ ++/* ++ * The threshold used to filter out thrashing areas, ++ * If it == 0, filtering is disabled, otherwise it's the percentage up-bound ++ * of the thrashing ratio of all areas. Any area with a bigger thrashing ratio ++ * will be considered as having a zero duplication ratio. ++ */ ++static unsigned int uksm_thrash_threshold = 50; ++ ++/* How much dedup ratio is considered to be abundant*/ ++static unsigned int uksm_abundant_threshold = 10; ++ ++/* All slots having merged pages in this eval round. */ ++struct list_head vma_slot_dedup = LIST_HEAD_INIT(vma_slot_dedup); ++ ++/* How many times the ksmd has slept since startup */ ++static unsigned long long uksm_sleep_times; ++ ++#define UKSM_RUN_STOP 0 ++#define UKSM_RUN_MERGE 1 ++static unsigned int uksm_run = 1; ++ ++static DECLARE_WAIT_QUEUE_HEAD(uksm_thread_wait); ++static DEFINE_MUTEX(uksm_thread_mutex); ++ ++/* ++ * List vma_slot_new is for newly created vma_slot waiting to be added by ++ * ksmd. If one cannot be added(e.g. due to it's too small), it's moved to ++ * vma_slot_noadd. vma_slot_del is the list for vma_slot whose corresponding ++ * VMA has been removed/freed. ++ */ ++struct list_head vma_slot_new = LIST_HEAD_INIT(vma_slot_new); ++struct list_head vma_slot_noadd = LIST_HEAD_INIT(vma_slot_noadd); ++struct list_head vma_slot_del = LIST_HEAD_INIT(vma_slot_del); ++static DEFINE_SPINLOCK(vma_slot_list_lock); ++ ++/* The unstable tree heads */ ++static struct rb_root root_unstable_tree = RB_ROOT; ++ ++/* ++ * All tree_nodes are in a list to be freed at once when unstable tree is ++ * freed after each scan round. ++ */ ++static struct list_head unstable_tree_node_list = ++ LIST_HEAD_INIT(unstable_tree_node_list); ++ ++/* List contains all stable nodes */ ++static struct list_head stable_node_list = LIST_HEAD_INIT(stable_node_list); ++ ++/* ++ * When the hash strength is changed, the stable tree must be delta_hashed and ++ * re-structured. We use two set of below structs to speed up the ++ * re-structuring of stable tree. ++ */ ++static struct list_head ++stable_tree_node_list[2] = {LIST_HEAD_INIT(stable_tree_node_list[0]), ++ LIST_HEAD_INIT(stable_tree_node_list[1])}; ++ ++static struct list_head *stable_tree_node_listp = &stable_tree_node_list[0]; ++static struct rb_root root_stable_tree[2] = {RB_ROOT, RB_ROOT}; ++static struct rb_root *root_stable_treep = &root_stable_tree[0]; ++static unsigned long stable_tree_index; ++ ++/* The hash strength needed to hash a full page */ ++#define HASH_STRENGTH_FULL (PAGE_SIZE / sizeof(u32)) ++ ++/* The hash strength needed for loop-back hashing */ ++#define HASH_STRENGTH_MAX (HASH_STRENGTH_FULL + 10) ++ ++/* The random offsets in a page */ ++static u32 *random_nums; ++ ++/* The hash strength */ ++static unsigned long hash_strength = HASH_STRENGTH_FULL >> 4; ++ ++/* The delta value each time the hash strength increases or decreases */ ++static unsigned long hash_strength_delta; ++#define HASH_STRENGTH_DELTA_MAX 5 ++ ++/* The time we have saved due to random_sample_hash */ ++static u64 rshash_pos; ++ ++/* The time we have wasted due to hash collision */ ++static u64 rshash_neg; ++ ++struct uksm_benefit { ++ u64 pos; ++ u64 neg; ++ u64 scanned; ++ unsigned long base; ++} benefit; ++ ++/* ++ * The relative cost of memcmp, compared to 1 time unit of random sample ++ * hash, this value is tested when ksm module is initialized ++ */ ++static unsigned long memcmp_cost; ++ ++static unsigned long rshash_neg_cont_zero; ++static unsigned long rshash_cont_obscure; ++ ++/* The possible states of hash strength adjustment heuristic */ ++enum rshash_states { ++ RSHASH_STILL, ++ RSHASH_TRYUP, ++ RSHASH_TRYDOWN, ++ RSHASH_NEW, ++ RSHASH_PRE_STILL, ++}; ++ ++/* The possible direction we are about to adjust hash strength */ ++enum rshash_direct { ++ GO_UP, ++ GO_DOWN, ++ OBSCURE, ++ STILL, ++}; ++ ++/* random sampling hash state machine */ ++static struct { ++ enum rshash_states state; ++ enum rshash_direct pre_direct; ++ u8 below_count; ++ /* Keep a lookup window of size 5, iff above_count/below_count > 3 ++ * in this window we stop trying. ++ */ ++ u8 lookup_window_index; ++ u64 stable_benefit; ++ unsigned long turn_point_down; ++ unsigned long turn_benefit_down; ++ unsigned long turn_point_up; ++ unsigned long turn_benefit_up; ++ unsigned long stable_point; ++} rshash_state; ++ ++/*zero page hash table, hash_strength [0 ~ HASH_STRENGTH_MAX]*/ ++static u32 *zero_hash_table; ++ ++static inline struct node_vma *alloc_node_vma(void) ++{ ++ struct node_vma *node_vma; ++ node_vma = kmem_cache_zalloc(node_vma_cache, GFP_KERNEL); ++ if (node_vma) { ++ INIT_HLIST_HEAD(&node_vma->rmap_hlist); ++ INIT_HLIST_NODE(&node_vma->hlist); ++ } ++ return node_vma; ++} ++ ++static inline void free_node_vma(struct node_vma *node_vma) ++{ ++ kmem_cache_free(node_vma_cache, node_vma); ++} ++ ++ ++static inline struct vma_slot *alloc_vma_slot(void) ++{ ++ struct vma_slot *slot; ++ ++ /* ++ * In case ksm is not initialized by now. ++ * Oops, we need to consider the call site of uksm_init() in the future. ++ */ ++ if (!vma_slot_cache) ++ return NULL; ++ ++ slot = kmem_cache_zalloc(vma_slot_cache, GFP_KERNEL); ++ if (slot) { ++ INIT_LIST_HEAD(&slot->slot_list); ++ INIT_LIST_HEAD(&slot->dedup_list); ++ slot->flags |= UKSM_SLOT_NEED_RERAND; ++ } ++ return slot; ++} ++ ++static inline void free_vma_slot(struct vma_slot *vma_slot) ++{ ++ kmem_cache_free(vma_slot_cache, vma_slot); ++} ++ ++ ++ ++static inline struct rmap_item *alloc_rmap_item(void) ++{ ++ struct rmap_item *rmap_item; ++ ++ rmap_item = kmem_cache_zalloc(rmap_item_cache, GFP_KERNEL); ++ if (rmap_item) { ++ /* bug on lowest bit is not clear for flag use */ ++ BUG_ON(is_addr(rmap_item)); ++ } ++ return rmap_item; ++} ++ ++static inline void free_rmap_item(struct rmap_item *rmap_item) ++{ ++ rmap_item->slot = NULL; /* debug safety */ ++ kmem_cache_free(rmap_item_cache, rmap_item); ++} ++ ++static inline struct stable_node *alloc_stable_node(void) ++{ ++ struct stable_node *node; ++ node = kmem_cache_alloc(stable_node_cache, GFP_KERNEL | GFP_ATOMIC); ++ if (!node) ++ return NULL; ++ ++ INIT_HLIST_HEAD(&node->hlist); ++ list_add(&node->all_list, &stable_node_list); ++ return node; ++} ++ ++static inline void free_stable_node(struct stable_node *stable_node) ++{ ++ list_del(&stable_node->all_list); ++ kmem_cache_free(stable_node_cache, stable_node); ++} ++ ++static inline struct tree_node *alloc_tree_node(struct list_head *list) ++{ ++ struct tree_node *node; ++ node = kmem_cache_zalloc(tree_node_cache, GFP_KERNEL | GFP_ATOMIC); ++ if (!node) ++ return NULL; ++ ++ list_add(&node->all_list, list); ++ return node; ++} ++ ++static inline void free_tree_node(struct tree_node *node) ++{ ++ list_del(&node->all_list); ++ kmem_cache_free(tree_node_cache, node); ++} ++ ++static void uksm_drop_anon_vma(struct rmap_item *rmap_item) ++{ ++ struct anon_vma *anon_vma = rmap_item->anon_vma; ++ ++ put_anon_vma(anon_vma); ++} ++ ++ ++/** ++ * Remove a stable node from stable_tree, may unlink from its tree_node and ++ * may remove its parent tree_node if no other stable node is pending. ++ * ++ * @stable_node The node need to be removed ++ * @unlink_rb Will this node be unlinked from the rbtree? ++ * @remove_tree_ node Will its tree_node be removed if empty? ++ */ ++static void remove_node_from_stable_tree(struct stable_node *stable_node, ++ int unlink_rb, int remove_tree_node) ++{ ++ struct node_vma *node_vma; ++ struct rmap_item *rmap_item; ++ struct hlist_node *n; ++ ++ if (!hlist_empty(&stable_node->hlist)) { ++ hlist_for_each_entry_safe(node_vma, n, ++ &stable_node->hlist, hlist) { ++ hlist_for_each_entry(rmap_item, &node_vma->rmap_hlist, hlist) { ++ uksm_pages_sharing--; ++ ++ uksm_drop_anon_vma(rmap_item); ++ rmap_item->address &= PAGE_MASK; ++ } ++ free_node_vma(node_vma); ++ cond_resched(); ++ } ++ ++ /* the last one is counted as shared */ ++ uksm_pages_shared--; ++ uksm_pages_sharing++; ++ } ++ ++ if (stable_node->tree_node && unlink_rb) { ++ rb_erase(&stable_node->node, ++ &stable_node->tree_node->sub_root); ++ ++ if (RB_EMPTY_ROOT(&stable_node->tree_node->sub_root) && ++ remove_tree_node) { ++ rb_erase(&stable_node->tree_node->node, ++ root_stable_treep); ++ free_tree_node(stable_node->tree_node); ++ } else { ++ stable_node->tree_node->count--; ++ } ++ } ++ ++ free_stable_node(stable_node); ++} ++ ++ ++/* ++ * get_uksm_page: checks if the page indicated by the stable node ++ * is still its ksm page, despite having held no reference to it. ++ * In which case we can trust the content of the page, and it ++ * returns the gotten page; but if the page has now been zapped, ++ * remove the stale node from the stable tree and return NULL. ++ * ++ * You would expect the stable_node to hold a reference to the ksm page. ++ * But if it increments the page's count, swapping out has to wait for ++ * ksmd to come around again before it can free the page, which may take ++ * seconds or even minutes: much too unresponsive. So instead we use a ++ * "keyhole reference": access to the ksm page from the stable node peeps ++ * out through its keyhole to see if that page still holds the right key, ++ * pointing back to this stable node. This relies on freeing a PageAnon ++ * page to reset its page->mapping to NULL, and relies on no other use of ++ * a page to put something that might look like our key in page->mapping. ++ * ++ * include/linux/pagemap.h page_cache_get_speculative() is a good reference, ++ * but this is different - made simpler by uksm_thread_mutex being held, but ++ * interesting for assuming that no other use of the struct page could ever ++ * put our expected_mapping into page->mapping (or a field of the union which ++ * coincides with page->mapping). The RCU calls are not for KSM at all, but ++ * to keep the page_count protocol described with page_cache_get_speculative. ++ * ++ * Note: it is possible that get_uksm_page() will return NULL one moment, ++ * then page the next, if the page is in between page_freeze_refs() and ++ * page_unfreeze_refs(): this shouldn't be a problem anywhere, the page ++ * is on its way to being freed; but it is an anomaly to bear in mind. ++ * ++ * @unlink_rb: if the removal of this node will firstly unlink from ++ * its rbtree. stable_node_reinsert will prevent this when restructuring the ++ * node from its old tree. ++ * ++ * @remove_tree_node: if this is the last one of its tree_node, will the ++ * tree_node be freed ? If we are inserting stable node, this tree_node may ++ * be reused, so don't free it. ++ */ ++static struct page *get_uksm_page(struct stable_node *stable_node, ++ int unlink_rb, int remove_tree_node) ++{ ++ struct page *page; ++ void *expected_mapping; ++ ++ page = pfn_to_page(stable_node->kpfn); ++ expected_mapping = (void *)stable_node + ++ (PAGE_MAPPING_ANON | PAGE_MAPPING_KSM); ++ rcu_read_lock(); ++ if (page->mapping != expected_mapping) ++ goto stale; ++ if (!get_page_unless_zero(page)) ++ goto stale; ++ if (page->mapping != expected_mapping) { ++ put_page(page); ++ goto stale; ++ } ++ rcu_read_unlock(); ++ return page; ++stale: ++ rcu_read_unlock(); ++ remove_node_from_stable_tree(stable_node, unlink_rb, remove_tree_node); ++ ++ return NULL; ++} ++ ++/* ++ * Removing rmap_item from stable or unstable tree. ++ * This function will clean the information from the stable/unstable tree. ++ */ ++static inline void remove_rmap_item_from_tree(struct rmap_item *rmap_item) ++{ ++ if (rmap_item->address & STABLE_FLAG) { ++ struct stable_node *stable_node; ++ struct node_vma *node_vma; ++ struct page *page; ++ ++ node_vma = rmap_item->head; ++ stable_node = node_vma->head; ++ page = get_uksm_page(stable_node, 1, 1); ++ if (!page) ++ goto out; ++ ++ /* ++ * page lock is needed because it's racing with ++ * try_to_unmap_ksm(), etc. ++ */ ++ lock_page(page); ++ hlist_del(&rmap_item->hlist); ++ ++ if (hlist_empty(&node_vma->rmap_hlist)) { ++ hlist_del(&node_vma->hlist); ++ free_node_vma(node_vma); ++ } ++ unlock_page(page); ++ ++ put_page(page); ++ if (hlist_empty(&stable_node->hlist)) { ++ /* do NOT call remove_node_from_stable_tree() here, ++ * it's possible for a forked rmap_item not in ++ * stable tree while the in-tree rmap_items were ++ * deleted. ++ */ ++ uksm_pages_shared--; ++ } else ++ uksm_pages_sharing--; ++ ++ ++ uksm_drop_anon_vma(rmap_item); ++ } else if (rmap_item->address & UNSTABLE_FLAG) { ++ if (rmap_item->hash_round == uksm_hash_round) { ++ ++ rb_erase(&rmap_item->node, ++ &rmap_item->tree_node->sub_root); ++ if (RB_EMPTY_ROOT(&rmap_item->tree_node->sub_root)) { ++ rb_erase(&rmap_item->tree_node->node, ++ &root_unstable_tree); ++ ++ free_tree_node(rmap_item->tree_node); ++ } else ++ rmap_item->tree_node->count--; ++ } ++ uksm_pages_unshared--; ++ } ++ ++ rmap_item->address &= PAGE_MASK; ++ rmap_item->hash_max = 0; ++ ++out: ++ cond_resched(); /* we're called from many long loops */ ++} ++ ++static inline int slot_in_uksm(struct vma_slot *slot) ++{ ++ return list_empty(&slot->slot_list); ++} ++ ++/* ++ * Test if the mm is exiting ++ */ ++static inline bool uksm_test_exit(struct mm_struct *mm) ++{ ++ return atomic_read(&mm->mm_users) == 0; ++} ++ ++/** ++ * Need to do two things: ++ * 1. check if slot was moved to del list ++ * 2. make sure the mmap_sem is manipulated under valid vma. ++ * ++ * My concern here is that in some cases, this may make ++ * vma_slot_list_lock() waiters to serialized further by some ++ * sem->wait_lock, can this really be expensive? ++ * ++ * ++ * @return ++ * 0: if successfully locked mmap_sem ++ * -ENOENT: this slot was moved to del list ++ * -EBUSY: vma lock failed ++ */ ++static int try_down_read_slot_mmap_sem(struct vma_slot *slot) ++{ ++ struct vm_area_struct *vma; ++ struct mm_struct *mm; ++ struct rw_semaphore *sem; ++ ++ spin_lock(&vma_slot_list_lock); ++ ++ /* the slot_list was removed and inited from new list, when it enters ++ * uksm_list. If now it's not empty, then it must be moved to del list ++ */ ++ if (!slot_in_uksm(slot)) { ++ spin_unlock(&vma_slot_list_lock); ++ return -ENOENT; ++ } ++ ++ BUG_ON(slot->pages != vma_pages(slot->vma)); ++ /* Ok, vma still valid */ ++ vma = slot->vma; ++ mm = vma->vm_mm; ++ sem = &mm->mmap_sem; ++ ++ if (uksm_test_exit(mm)) { ++ spin_unlock(&vma_slot_list_lock); ++ return -ENOENT; ++ } ++ ++ if (down_read_trylock(sem)) { ++ spin_unlock(&vma_slot_list_lock); ++ return 0; ++ } ++ ++ spin_unlock(&vma_slot_list_lock); ++ return -EBUSY; ++} ++ ++static inline unsigned long ++vma_page_address(struct page *page, struct vm_area_struct *vma) ++{ ++ pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT); ++ unsigned long address; ++ ++ address = vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT); ++ if (unlikely(address < vma->vm_start || address >= vma->vm_end)) { ++ /* page should be within @vma mapping range */ ++ return -EFAULT; ++ } ++ return address; ++} ++ ++ ++/* return 0 on success with the item's mmap_sem locked */ ++static inline int get_mergeable_page_lock_mmap(struct rmap_item *item) ++{ ++ struct mm_struct *mm; ++ struct vma_slot *slot = item->slot; ++ int err = -EINVAL; ++ ++ struct page *page; ++ ++ /* ++ * try_down_read_slot_mmap_sem() returns non-zero if the slot ++ * has been removed by uksm_remove_vma(). ++ */ ++ if (try_down_read_slot_mmap_sem(slot)) ++ return -EBUSY; ++ ++ mm = slot->vma->vm_mm; ++ ++ if (uksm_test_exit(mm)) ++ goto failout_up; ++ ++ page = item->page; ++ rcu_read_lock(); ++ if (!get_page_unless_zero(page)) { ++ rcu_read_unlock(); ++ goto failout_up; ++ } ++ ++ /* No need to consider huge page here. */ ++ if (item->slot->vma->anon_vma != page_anon_vma(page) || ++ vma_page_address(page, item->slot->vma) != get_rmap_addr(item)) { ++ /* ++ * TODO: ++ * should we release this item becase of its stale page ++ * mapping? ++ */ ++ put_page(page); ++ rcu_read_unlock(); ++ goto failout_up; ++ } ++ rcu_read_unlock(); ++ return 0; ++ ++failout_up: ++ up_read(&mm->mmap_sem); ++ return err; ++} ++ ++/* ++ * What kind of VMA is considered ? ++ */ ++static inline int vma_can_enter(struct vm_area_struct *vma) ++{ ++ return uksm_flags_can_scan(vma->vm_flags); ++} ++ ++/* ++ * Called whenever a fresh new vma is created A new vma_slot. ++ * is created and inserted into a global list Must be called. ++ * after vma is inserted to its mm . ++ */ ++void uksm_vma_add_new(struct vm_area_struct *vma) ++{ ++ struct vma_slot *slot; ++ ++ if (!vma_can_enter(vma)) { ++ vma->uksm_vma_slot = NULL; ++ return; ++ } ++ ++ slot = alloc_vma_slot(); ++ if (!slot) { ++ vma->uksm_vma_slot = NULL; ++ return; ++ } ++ ++ vma->uksm_vma_slot = slot; ++ vma->vm_flags |= VM_MERGEABLE; ++ slot->vma = vma; ++ slot->mm = vma->vm_mm; ++ slot->ctime_j = jiffies; ++ slot->pages = vma_pages(vma); ++ spin_lock(&vma_slot_list_lock); ++ list_add_tail(&slot->slot_list, &vma_slot_new); ++ spin_unlock(&vma_slot_list_lock); ++} ++ ++/* ++ * Called after vma is unlinked from its mm ++ */ ++void uksm_remove_vma(struct vm_area_struct *vma) ++{ ++ struct vma_slot *slot; ++ ++ if (!vma->uksm_vma_slot) ++ return; ++ ++ slot = vma->uksm_vma_slot; ++ spin_lock(&vma_slot_list_lock); ++ if (slot_in_uksm(slot)) { ++ /** ++ * This slot has been added by ksmd, so move to the del list ++ * waiting ksmd to free it. ++ */ ++ list_add_tail(&slot->slot_list, &vma_slot_del); ++ } else { ++ /** ++ * It's still on new list. It's ok to free slot directly. ++ */ ++ list_del(&slot->slot_list); ++ free_vma_slot(slot); ++ } ++ spin_unlock(&vma_slot_list_lock); ++ vma->uksm_vma_slot = NULL; ++} ++ ++/* 32/3 < they < 32/2 */ ++#define shiftl 8 ++#define shiftr 12 ++ ++#define HASH_FROM_TO(from, to) \ ++for (index = from; index < to; index++) { \ ++ pos = random_nums[index]; \ ++ hash += key[pos]; \ ++ hash += (hash << shiftl); \ ++ hash ^= (hash >> shiftr); \ ++} ++ ++ ++#define HASH_FROM_DOWN_TO(from, to) \ ++for (index = from - 1; index >= to; index--) { \ ++ hash ^= (hash >> shiftr); \ ++ hash ^= (hash >> (shiftr*2)); \ ++ hash -= (hash << shiftl); \ ++ hash += (hash << (shiftl*2)); \ ++ pos = random_nums[index]; \ ++ hash -= key[pos]; \ ++} ++ ++/* ++ * The main random sample hash function. ++ */ ++static u32 random_sample_hash(void *addr, u32 hash_strength) ++{ ++ u32 hash = 0xdeadbeef; ++ int index, pos, loop = hash_strength; ++ u32 *key = (u32 *)addr; ++ ++ if (loop > HASH_STRENGTH_FULL) ++ loop = HASH_STRENGTH_FULL; ++ ++ HASH_FROM_TO(0, loop); ++ ++ if (hash_strength > HASH_STRENGTH_FULL) { ++ loop = hash_strength - HASH_STRENGTH_FULL; ++ HASH_FROM_TO(0, loop); ++ } ++ ++ return hash; ++} ++ ++ ++/** ++ * It's used when hash strength is adjusted ++ * ++ * @addr The page's virtual address ++ * @from The original hash strength ++ * @to The hash strength changed to ++ * @hash The hash value generated with "from" hash value ++ * ++ * return the hash value ++ */ ++static u32 delta_hash(void *addr, int from, int to, u32 hash) ++{ ++ u32 *key = (u32 *)addr; ++ int index, pos; /* make sure they are int type */ ++ ++ if (to > from) { ++ if (from >= HASH_STRENGTH_FULL) { ++ from -= HASH_STRENGTH_FULL; ++ to -= HASH_STRENGTH_FULL; ++ HASH_FROM_TO(from, to); ++ } else if (to <= HASH_STRENGTH_FULL) { ++ HASH_FROM_TO(from, to); ++ } else { ++ HASH_FROM_TO(from, HASH_STRENGTH_FULL); ++ HASH_FROM_TO(0, to - HASH_STRENGTH_FULL); ++ } ++ } else { ++ if (from <= HASH_STRENGTH_FULL) { ++ HASH_FROM_DOWN_TO(from, to); ++ } else if (to >= HASH_STRENGTH_FULL) { ++ from -= HASH_STRENGTH_FULL; ++ to -= HASH_STRENGTH_FULL; ++ HASH_FROM_DOWN_TO(from, to); ++ } else { ++ HASH_FROM_DOWN_TO(from - HASH_STRENGTH_FULL, 0); ++ HASH_FROM_DOWN_TO(HASH_STRENGTH_FULL, to); ++ } ++ } ++ ++ return hash; ++} ++ ++ ++ ++ ++#define CAN_OVERFLOW_U64(x, delta) (U64_MAX - (x) < (delta)) ++ ++/** ++ * ++ * Called when: rshash_pos or rshash_neg is about to overflow or a scan round ++ * has finished. ++ * ++ * return 0 if no page has been scanned since last call, 1 otherwise. ++ */ ++static inline int encode_benefit(void) ++{ ++ u64 scanned_delta, pos_delta, neg_delta; ++ unsigned long base = benefit.base; ++ ++ scanned_delta = uksm_pages_scanned - uksm_pages_scanned_last; ++ ++ if (!scanned_delta) ++ return 0; ++ ++ scanned_delta >>= base; ++ pos_delta = rshash_pos >> base; ++ neg_delta = rshash_neg >> base; ++ ++ if (CAN_OVERFLOW_U64(benefit.pos, pos_delta) || ++ CAN_OVERFLOW_U64(benefit.neg, neg_delta) || ++ CAN_OVERFLOW_U64(benefit.scanned, scanned_delta)) { ++ benefit.scanned >>= 1; ++ benefit.neg >>= 1; ++ benefit.pos >>= 1; ++ benefit.base++; ++ scanned_delta >>= 1; ++ pos_delta >>= 1; ++ neg_delta >>= 1; ++ } ++ ++ benefit.pos += pos_delta; ++ benefit.neg += neg_delta; ++ benefit.scanned += scanned_delta; ++ ++ BUG_ON(!benefit.scanned); ++ ++ rshash_pos = rshash_neg = 0; ++ uksm_pages_scanned_last = uksm_pages_scanned; ++ ++ return 1; ++} ++ ++static inline void reset_benefit(void) ++{ ++ benefit.pos = 0; ++ benefit.neg = 0; ++ benefit.base = 0; ++ benefit.scanned = 0; ++} ++ ++static inline void inc_rshash_pos(unsigned long delta) ++{ ++ if (CAN_OVERFLOW_U64(rshash_pos, delta)) ++ encode_benefit(); ++ ++ rshash_pos += delta; ++} ++ ++static inline void inc_rshash_neg(unsigned long delta) ++{ ++ if (CAN_OVERFLOW_U64(rshash_neg, delta)) ++ encode_benefit(); ++ ++ rshash_neg += delta; ++} ++ ++ ++static inline u32 page_hash(struct page *page, unsigned long hash_strength, ++ int cost_accounting) ++{ ++ u32 val; ++ unsigned long delta; ++ ++ void *addr = kmap_atomic(page); ++ ++ val = random_sample_hash(addr, hash_strength); ++ kunmap_atomic(addr); ++ ++ if (cost_accounting) { ++ if (HASH_STRENGTH_FULL > hash_strength) ++ delta = HASH_STRENGTH_FULL - hash_strength; ++ else ++ delta = 0; ++ ++ inc_rshash_pos(delta); ++ } ++ ++ return val; ++} ++ ++static int memcmp_pages(struct page *page1, struct page *page2, ++ int cost_accounting) ++{ ++ char *addr1, *addr2; ++ int ret; ++ ++ addr1 = kmap_atomic(page1); ++ addr2 = kmap_atomic(page2); ++ ret = memcmp(addr1, addr2, PAGE_SIZE); ++ kunmap_atomic(addr2); ++ kunmap_atomic(addr1); ++ ++ if (cost_accounting) ++ inc_rshash_neg(memcmp_cost); ++ ++ return ret; ++} ++ ++static inline int pages_identical(struct page *page1, struct page *page2) ++{ ++ return !memcmp_pages(page1, page2, 0); ++} ++ ++static inline int is_page_full_zero(struct page *page) ++{ ++ char *addr; ++ int ret; ++ ++ addr = kmap_atomic(page); ++ ret = is_full_zero(addr, PAGE_SIZE); ++ kunmap_atomic(addr); ++ ++ return ret; ++} ++ ++static int write_protect_page(struct vm_area_struct *vma, struct page *page, ++ pte_t *orig_pte, pte_t *old_pte) ++{ ++ struct mm_struct *mm = vma->vm_mm; ++ unsigned long addr; ++ pte_t *ptep; ++ spinlock_t *ptl; ++ int swapped; ++ int err = -EFAULT; ++ unsigned long mmun_start; /* For mmu_notifiers */ ++ unsigned long mmun_end; /* For mmu_notifiers */ ++ ++ addr = page_address_in_vma(page, vma); ++ if (addr == -EFAULT) ++ goto out; ++ ++ BUG_ON(PageTransCompound(page)); ++ ++ mmun_start = addr; ++ mmun_end = addr + PAGE_SIZE; ++ mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); ++ ++ ptep = page_check_address(page, mm, addr, &ptl, 0); ++ if (!ptep) ++ goto out_mn; ++ ++ if (old_pte) ++ *old_pte = *ptep; ++ ++ if (pte_write(*ptep) || pte_dirty(*ptep)) { ++ pte_t entry; ++ ++ swapped = PageSwapCache(page); ++ flush_cache_page(vma, addr, page_to_pfn(page)); ++ /* ++ * Ok this is tricky, when get_user_pages_fast() run it doesnt ++ * take any lock, therefore the check that we are going to make ++ * with the pagecount against the mapcount is racey and ++ * O_DIRECT can happen right after the check. ++ * So we clear the pte and flush the tlb before the check ++ * this assure us that no O_DIRECT can happen after the check ++ * or in the middle of the check. ++ */ ++ entry = ptep_clear_flush(vma, addr, ptep); ++ /* ++ * Check that no O_DIRECT or similar I/O is in progress on the ++ * page ++ */ ++ if (page_mapcount(page) + 1 + swapped != page_count(page)) { ++ set_pte_at(mm, addr, ptep, entry); ++ goto out_unlock; ++ } ++ if (pte_dirty(entry)) ++ set_page_dirty(page); ++ entry = pte_mkclean(pte_wrprotect(entry)); ++ set_pte_at_notify(mm, addr, ptep, entry); ++ } ++ *orig_pte = *ptep; ++ err = 0; ++ ++out_unlock: ++ pte_unmap_unlock(ptep, ptl); ++out_mn: ++ mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); ++out: ++ return err; ++} ++ ++#define MERGE_ERR_PGERR 1 /* the page is invalid cannot continue */ ++#define MERGE_ERR_COLLI 2 /* there is a collision */ ++#define MERGE_ERR_COLLI_MAX 3 /* collision at the max hash strength */ ++#define MERGE_ERR_CHANGED 4 /* the page has changed since last hash */ ++ ++ ++/** ++ * replace_page - replace page in vma by new ksm page ++ * @vma: vma that holds the pte pointing to page ++ * @page: the page we are replacing by kpage ++ * @kpage: the ksm page we replace page by ++ * @orig_pte: the original value of the pte ++ * ++ * Returns 0 on success, MERGE_ERR_PGERR on failure. ++ */ ++static int replace_page(struct vm_area_struct *vma, struct page *page, ++ struct page *kpage, pte_t orig_pte) ++{ ++ struct mm_struct *mm = vma->vm_mm; ++ pgd_t *pgd; ++ pud_t *pud; ++ pmd_t *pmd; ++ pte_t *ptep; ++ spinlock_t *ptl; ++ pte_t entry; ++ ++ unsigned long addr; ++ int err = MERGE_ERR_PGERR; ++ unsigned long mmun_start; /* For mmu_notifiers */ ++ unsigned long mmun_end; /* For mmu_notifiers */ ++ ++ addr = page_address_in_vma(page, vma); ++ if (addr == -EFAULT) ++ goto out; ++ ++ pgd = pgd_offset(mm, addr); ++ if (!pgd_present(*pgd)) ++ goto out; ++ ++ pud = pud_offset(pgd, addr); ++ if (!pud_present(*pud)) ++ goto out; ++ ++ pmd = pmd_offset(pud, addr); ++ BUG_ON(pmd_trans_huge(*pmd)); ++ if (!pmd_present(*pmd)) ++ goto out; ++ ++ mmun_start = addr; ++ mmun_end = addr + PAGE_SIZE; ++ mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); ++ ++ ptep = pte_offset_map_lock(mm, pmd, addr, &ptl); ++ if (!pte_same(*ptep, orig_pte)) { ++ pte_unmap_unlock(ptep, ptl); ++ goto out_mn; ++ } ++ ++ flush_cache_page(vma, addr, pte_pfn(*ptep)); ++ ptep_clear_flush(vma, addr, ptep); ++ entry = mk_pte(kpage, vma->vm_page_prot); ++ ++ /* special treatment is needed for zero_page */ ++ if ((page_to_pfn(kpage) == uksm_zero_pfn) || ++ (page_to_pfn(kpage) == zero_pfn)) ++ entry = pte_mkspecial(entry); ++ else { ++ get_page(kpage); ++ page_add_anon_rmap(kpage, vma, addr); ++ } ++ ++ set_pte_at_notify(mm, addr, ptep, entry); ++ ++ page_remove_rmap(page); ++ if (!page_mapped(page)) ++ try_to_free_swap(page); ++ put_page(page); ++ ++ pte_unmap_unlock(ptep, ptl); ++ err = 0; ++out_mn: ++ mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); ++out: ++ return err; ++} ++ ++ ++/** ++ * Fully hash a page with HASH_STRENGTH_MAX return a non-zero hash value. The ++ * zero hash value at HASH_STRENGTH_MAX is used to indicated that its ++ * hash_max member has not been calculated. ++ * ++ * @page The page needs to be hashed ++ * @hash_old The hash value calculated with current hash strength ++ * ++ * return the new hash value calculated at HASH_STRENGTH_MAX ++ */ ++static inline u32 page_hash_max(struct page *page, u32 hash_old) ++{ ++ u32 hash_max = 0; ++ void *addr; ++ ++ addr = kmap_atomic(page); ++ hash_max = delta_hash(addr, hash_strength, ++ HASH_STRENGTH_MAX, hash_old); ++ ++ kunmap_atomic(addr); ++ ++ if (!hash_max) ++ hash_max = 1; ++ ++ inc_rshash_neg(HASH_STRENGTH_MAX - hash_strength); ++ return hash_max; ++} ++ ++/* ++ * We compare the hash again, to ensure that it is really a hash collision ++ * instead of being caused by page write. ++ */ ++static inline int check_collision(struct rmap_item *rmap_item, ++ u32 hash) ++{ ++ int err; ++ struct page *page = rmap_item->page; ++ ++ /* if this rmap_item has already been hash_maxed, then the collision ++ * must appears in the second-level rbtree search. In this case we check ++ * if its hash_max value has been changed. Otherwise, the collision ++ * happens in the first-level rbtree search, so we check against it's ++ * current hash value. ++ */ ++ if (rmap_item->hash_max) { ++ inc_rshash_neg(memcmp_cost); ++ inc_rshash_neg(HASH_STRENGTH_MAX - hash_strength); ++ ++ if (rmap_item->hash_max == page_hash_max(page, hash)) ++ err = MERGE_ERR_COLLI; ++ else ++ err = MERGE_ERR_CHANGED; ++ } else { ++ inc_rshash_neg(memcmp_cost + hash_strength); ++ ++ if (page_hash(page, hash_strength, 0) == hash) ++ err = MERGE_ERR_COLLI; ++ else ++ err = MERGE_ERR_CHANGED; ++ } ++ ++ return err; ++} ++ ++static struct page *page_trans_compound_anon(struct page *page) ++{ ++ if (PageTransCompound(page)) { ++ struct page *head = compound_trans_head(page); ++ /* ++ * head may actually be splitted and freed from under ++ * us but it's ok here. ++ */ ++ if (PageAnon(head)) ++ return head; ++ } ++ return NULL; ++} ++ ++static int page_trans_compound_anon_split(struct page *page) ++{ ++ int ret = 0; ++ struct page *transhuge_head = page_trans_compound_anon(page); ++ if (transhuge_head) { ++ /* Get the reference on the head to split it. */ ++ if (get_page_unless_zero(transhuge_head)) { ++ /* ++ * Recheck we got the reference while the head ++ * was still anonymous. ++ */ ++ if (PageAnon(transhuge_head)) ++ ret = split_huge_page(transhuge_head); ++ else ++ /* ++ * Retry later if split_huge_page run ++ * from under us. ++ */ ++ ret = 1; ++ put_page(transhuge_head); ++ } else ++ /* Retry later if split_huge_page run from under us. */ ++ ret = 1; ++ } ++ return ret; ++} ++ ++/** ++ * Try to merge a rmap_item.page with a kpage in stable node. kpage must ++ * already be a ksm page. ++ * ++ * @return 0 if the pages were merged, -EFAULT otherwise. ++ */ ++static int try_to_merge_with_uksm_page(struct rmap_item *rmap_item, ++ struct page *kpage, u32 hash) ++{ ++ struct vm_area_struct *vma = rmap_item->slot->vma; ++ struct mm_struct *mm = vma->vm_mm; ++ pte_t orig_pte = __pte(0); ++ int err = MERGE_ERR_PGERR; ++ struct page *page; ++ ++ if (uksm_test_exit(mm)) ++ goto out; ++ ++ page = rmap_item->page; ++ ++ if (page == kpage) { /* ksm page forked */ ++ err = 0; ++ goto out; ++ } ++ ++ if (PageTransCompound(page) && page_trans_compound_anon_split(page)) ++ goto out; ++ BUG_ON(PageTransCompound(page)); ++ ++ if (!PageAnon(page) || !PageKsm(kpage)) ++ goto out; ++ ++ /* ++ * We need the page lock to read a stable PageSwapCache in ++ * write_protect_page(). We use trylock_page() instead of ++ * lock_page() because we don't want to wait here - we ++ * prefer to continue scanning and merging different pages, ++ * then come back to this page when it is unlocked. ++ */ ++ if (!trylock_page(page)) ++ goto out; ++ /* ++ * If this anonymous page is mapped only here, its pte may need ++ * to be write-protected. If it's mapped elsewhere, all of its ++ * ptes are necessarily already write-protected. But in either ++ * case, we need to lock and check page_count is not raised. ++ */ ++ if (write_protect_page(vma, page, &orig_pte, NULL) == 0) { ++ if (pages_identical(page, kpage)) ++ err = replace_page(vma, page, kpage, orig_pte); ++ else ++ err = check_collision(rmap_item, hash); ++ } ++ ++ if ((vma->vm_flags & VM_LOCKED) && kpage && !err) { ++ munlock_vma_page(page); ++ if (!PageMlocked(kpage)) { ++ unlock_page(page); ++ lock_page(kpage); ++ mlock_vma_page(kpage); ++ page = kpage; /* for final unlock */ ++ } ++ } ++ ++ unlock_page(page); ++out: ++ return err; ++} ++ ++ ++ ++/** ++ * If two pages fail to merge in try_to_merge_two_pages, then we have a chance ++ * to restore a page mapping that has been changed in try_to_merge_two_pages. ++ * ++ * @return 0 on success. ++ */ ++static int restore_uksm_page_pte(struct vm_area_struct *vma, unsigned long addr, ++ pte_t orig_pte, pte_t wprt_pte) ++{ ++ struct mm_struct *mm = vma->vm_mm; ++ pgd_t *pgd; ++ pud_t *pud; ++ pmd_t *pmd; ++ pte_t *ptep; ++ spinlock_t *ptl; ++ ++ int err = -EFAULT; ++ ++ pgd = pgd_offset(mm, addr); ++ if (!pgd_present(*pgd)) ++ goto out; ++ ++ pud = pud_offset(pgd, addr); ++ if (!pud_present(*pud)) ++ goto out; ++ ++ pmd = pmd_offset(pud, addr); ++ if (!pmd_present(*pmd)) ++ goto out; ++ ++ ptep = pte_offset_map_lock(mm, pmd, addr, &ptl); ++ if (!pte_same(*ptep, wprt_pte)) { ++ /* already copied, let it be */ ++ pte_unmap_unlock(ptep, ptl); ++ goto out; ++ } ++ ++ /* ++ * Good boy, still here. When we still get the ksm page, it does not ++ * return to the free page pool, there is no way that a pte was changed ++ * to other page and gets back to this page. And remind that ksm page ++ * do not reuse in do_wp_page(). So it's safe to restore the original ++ * pte. ++ */ ++ flush_cache_page(vma, addr, pte_pfn(*ptep)); ++ ptep_clear_flush(vma, addr, ptep); ++ set_pte_at_notify(mm, addr, ptep, orig_pte); ++ ++ pte_unmap_unlock(ptep, ptl); ++ err = 0; ++out: ++ return err; ++} ++ ++/** ++ * try_to_merge_two_pages() - take two identical pages and prepare ++ * them to be merged into one page(rmap_item->page) ++ * ++ * @return 0 if we successfully merged two identical pages into ++ * one ksm page. MERGE_ERR_COLLI if it's only a hash collision ++ * search in rbtree. MERGE_ERR_CHANGED if rmap_item has been ++ * changed since it's hashed. MERGE_ERR_PGERR otherwise. ++ * ++ */ ++static int try_to_merge_two_pages(struct rmap_item *rmap_item, ++ struct rmap_item *tree_rmap_item, ++ u32 hash) ++{ ++ pte_t orig_pte1 = __pte(0), orig_pte2 = __pte(0); ++ pte_t wprt_pte1 = __pte(0), wprt_pte2 = __pte(0); ++ struct vm_area_struct *vma1 = rmap_item->slot->vma; ++ struct vm_area_struct *vma2 = tree_rmap_item->slot->vma; ++ struct page *page = rmap_item->page; ++ struct page *tree_page = tree_rmap_item->page; ++ int err = MERGE_ERR_PGERR; ++ struct address_space *saved_mapping; ++ ++ ++ if (rmap_item->page == tree_rmap_item->page) ++ goto out; ++ ++ if (PageTransCompound(page) && page_trans_compound_anon_split(page)) ++ goto out; ++ BUG_ON(PageTransCompound(page)); ++ ++ if (PageTransCompound(tree_page) && page_trans_compound_anon_split(tree_page)) ++ goto out; ++ BUG_ON(PageTransCompound(tree_page)); ++ ++ if (!PageAnon(page) || !PageAnon(tree_page)) ++ goto out; ++ ++ if (!trylock_page(page)) ++ goto out; ++ ++ ++ if (write_protect_page(vma1, page, &wprt_pte1, &orig_pte1) != 0) { ++ unlock_page(page); ++ goto out; ++ } ++ ++ /* ++ * While we hold page lock, upgrade page from ++ * PageAnon+anon_vma to PageKsm+NULL stable_node: ++ * stable_tree_insert() will update stable_node. ++ */ ++ saved_mapping = page->mapping; ++ set_page_stable_node(page, NULL); ++ mark_page_accessed(page); ++ unlock_page(page); ++ ++ if (!trylock_page(tree_page)) ++ goto restore_out; ++ ++ if (write_protect_page(vma2, tree_page, &wprt_pte2, &orig_pte2) != 0) { ++ unlock_page(tree_page); ++ goto restore_out; ++ } ++ ++ if (pages_identical(page, tree_page)) { ++ err = replace_page(vma2, tree_page, page, wprt_pte2); ++ if (err) { ++ unlock_page(tree_page); ++ goto restore_out; ++ } ++ ++ if ((vma2->vm_flags & VM_LOCKED)) { ++ munlock_vma_page(tree_page); ++ if (!PageMlocked(page)) { ++ unlock_page(tree_page); ++ lock_page(page); ++ mlock_vma_page(page); ++ tree_page = page; /* for final unlock */ ++ } ++ } ++ ++ unlock_page(tree_page); ++ ++ goto out; /* success */ ++ ++ } else { ++ if (tree_rmap_item->hash_max && ++ tree_rmap_item->hash_max == rmap_item->hash_max) { ++ err = MERGE_ERR_COLLI_MAX; ++ } else if (page_hash(page, hash_strength, 0) == ++ page_hash(tree_page, hash_strength, 0)) { ++ inc_rshash_neg(memcmp_cost + hash_strength * 2); ++ err = MERGE_ERR_COLLI; ++ } else { ++ err = MERGE_ERR_CHANGED; ++ } ++ ++ unlock_page(tree_page); ++ } ++ ++restore_out: ++ lock_page(page); ++ if (!restore_uksm_page_pte(vma1, get_rmap_addr(rmap_item), ++ orig_pte1, wprt_pte1)) ++ page->mapping = saved_mapping; ++ ++ unlock_page(page); ++out: ++ return err; ++} ++ ++static inline int hash_cmp(u32 new_val, u32 node_val) ++{ ++ if (new_val > node_val) ++ return 1; ++ else if (new_val < node_val) ++ return -1; ++ else ++ return 0; ++} ++ ++static inline u32 rmap_item_hash_max(struct rmap_item *item, u32 hash) ++{ ++ u32 hash_max = item->hash_max; ++ ++ if (!hash_max) { ++ hash_max = page_hash_max(item->page, hash); ++ ++ item->hash_max = hash_max; ++ } ++ ++ return hash_max; ++} ++ ++ ++ ++/** ++ * stable_tree_search() - search the stable tree for a page ++ * ++ * @item: the rmap_item we are comparing with ++ * @hash: the hash value of this item->page already calculated ++ * ++ * @return the page we have found, NULL otherwise. The page returned has ++ * been gotten. ++ */ ++static struct page *stable_tree_search(struct rmap_item *item, u32 hash) ++{ ++ struct rb_node *node = root_stable_treep->rb_node; ++ struct tree_node *tree_node; ++ unsigned long hash_max; ++ struct page *page = item->page; ++ struct stable_node *stable_node; ++ ++ stable_node = page_stable_node(page); ++ if (stable_node) { ++ /* ksm page forked, that is ++ * if (PageKsm(page) && !in_stable_tree(rmap_item)) ++ * it's actually gotten once outside. ++ */ ++ get_page(page); ++ return page; ++ } ++ ++ while (node) { ++ int cmp; ++ ++ tree_node = rb_entry(node, struct tree_node, node); ++ ++ cmp = hash_cmp(hash, tree_node->hash); ++ ++ if (cmp < 0) ++ node = node->rb_left; ++ else if (cmp > 0) ++ node = node->rb_right; ++ else ++ break; ++ } ++ ++ if (!node) ++ return NULL; ++ ++ if (tree_node->count == 1) { ++ stable_node = rb_entry(tree_node->sub_root.rb_node, ++ struct stable_node, node); ++ BUG_ON(!stable_node); ++ ++ goto get_page_out; ++ } ++ ++ /* ++ * ok, we have to search the second ++ * level subtree, hash the page to a ++ * full strength. ++ */ ++ node = tree_node->sub_root.rb_node; ++ BUG_ON(!node); ++ hash_max = rmap_item_hash_max(item, hash); ++ ++ while (node) { ++ int cmp; ++ ++ stable_node = rb_entry(node, struct stable_node, node); ++ ++ cmp = hash_cmp(hash_max, stable_node->hash_max); ++ ++ if (cmp < 0) ++ node = node->rb_left; ++ else if (cmp > 0) ++ node = node->rb_right; ++ else ++ goto get_page_out; ++ } ++ ++ return NULL; ++ ++get_page_out: ++ page = get_uksm_page(stable_node, 1, 1); ++ return page; ++} ++ ++static int try_merge_rmap_item(struct rmap_item *item, ++ struct page *kpage, ++ struct page *tree_page) ++{ ++ spinlock_t *ptl; ++ pte_t *ptep; ++ unsigned long addr; ++ struct vm_area_struct *vma = item->slot->vma; ++ ++ addr = get_rmap_addr(item); ++ ptep = page_check_address(kpage, vma->vm_mm, addr, &ptl, 0); ++ if (!ptep) ++ return 0; ++ ++ if (pte_write(*ptep)) { ++ /* has changed, abort! */ ++ pte_unmap_unlock(ptep, ptl); ++ return 0; ++ } ++ ++ get_page(tree_page); ++ page_add_anon_rmap(tree_page, vma, addr); ++ ++ flush_cache_page(vma, addr, pte_pfn(*ptep)); ++ ptep_clear_flush(vma, addr, ptep); ++ set_pte_at_notify(vma->vm_mm, addr, ptep, ++ mk_pte(tree_page, vma->vm_page_prot)); ++ ++ page_remove_rmap(kpage); ++ put_page(kpage); ++ ++ pte_unmap_unlock(ptep, ptl); ++ ++ return 1; ++} ++ ++/** ++ * try_to_merge_with_stable_page() - when two rmap_items need to be inserted ++ * into stable tree, the page was found to be identical to a stable ksm page, ++ * this is the last chance we can merge them into one. ++ * ++ * @item1: the rmap_item holding the page which we wanted to insert ++ * into stable tree. ++ * @item2: the other rmap_item we found when unstable tree search ++ * @oldpage: the page currently mapped by the two rmap_items ++ * @tree_page: the page we found identical in stable tree node ++ * @success1: return if item1 is successfully merged ++ * @success2: return if item2 is successfully merged ++ */ ++static void try_merge_with_stable(struct rmap_item *item1, ++ struct rmap_item *item2, ++ struct page **kpage, ++ struct page *tree_page, ++ int *success1, int *success2) ++{ ++ struct vm_area_struct *vma1 = item1->slot->vma; ++ struct vm_area_struct *vma2 = item2->slot->vma; ++ *success1 = 0; ++ *success2 = 0; ++ ++ if (unlikely(*kpage == tree_page)) { ++ /* I don't think this can really happen */ ++ printk(KERN_WARNING "UKSM: unexpected condition detected in " ++ "try_merge_with_stable() -- *kpage == tree_page !\n"); ++ *success1 = 1; ++ *success2 = 1; ++ return; ++ } ++ ++ if (!PageAnon(*kpage) || !PageKsm(*kpage)) ++ goto failed; ++ ++ if (!trylock_page(tree_page)) ++ goto failed; ++ ++ /* If the oldpage is still ksm and still pointed ++ * to in the right place, and still write protected, ++ * we are confident it's not changed, no need to ++ * memcmp anymore. ++ * be ware, we cannot take nested pte locks, ++ * deadlock risk. ++ */ ++ if (!try_merge_rmap_item(item1, *kpage, tree_page)) ++ goto unlock_failed; ++ ++ /* ok, then vma2, remind that pte1 already set */ ++ if (!try_merge_rmap_item(item2, *kpage, tree_page)) ++ goto success_1; ++ ++ *success2 = 1; ++success_1: ++ *success1 = 1; ++ ++ ++ if ((*success1 && vma1->vm_flags & VM_LOCKED) || ++ (*success2 && vma2->vm_flags & VM_LOCKED)) { ++ munlock_vma_page(*kpage); ++ if (!PageMlocked(tree_page)) ++ mlock_vma_page(tree_page); ++ } ++ ++ /* ++ * We do not need oldpage any more in the caller, so can break the lock ++ * now. ++ */ ++ unlock_page(*kpage); ++ *kpage = tree_page; /* Get unlocked outside. */ ++ return; ++ ++unlock_failed: ++ unlock_page(tree_page); ++failed: ++ return; ++} ++ ++static inline void stable_node_hash_max(struct stable_node *node, ++ struct page *page, u32 hash) ++{ ++ u32 hash_max = node->hash_max; ++ ++ if (!hash_max) { ++ hash_max = page_hash_max(page, hash); ++ node->hash_max = hash_max; ++ } ++} ++ ++static inline ++struct stable_node *new_stable_node(struct tree_node *tree_node, ++ struct page *kpage, u32 hash_max) ++{ ++ struct stable_node *new_stable_node; ++ ++ new_stable_node = alloc_stable_node(); ++ if (!new_stable_node) ++ return NULL; ++ ++ new_stable_node->kpfn = page_to_pfn(kpage); ++ new_stable_node->hash_max = hash_max; ++ new_stable_node->tree_node = tree_node; ++ set_page_stable_node(kpage, new_stable_node); ++ ++ return new_stable_node; ++} ++ ++static inline ++struct stable_node *first_level_insert(struct tree_node *tree_node, ++ struct rmap_item *rmap_item, ++ struct rmap_item *tree_rmap_item, ++ struct page **kpage, u32 hash, ++ int *success1, int *success2) ++{ ++ int cmp; ++ struct page *tree_page; ++ u32 hash_max = 0; ++ struct stable_node *stable_node, *new_snode; ++ struct rb_node *parent = NULL, **new; ++ ++ /* this tree node contains no sub-tree yet */ ++ stable_node = rb_entry(tree_node->sub_root.rb_node, ++ struct stable_node, node); ++ ++ tree_page = get_uksm_page(stable_node, 1, 0); ++ if (tree_page) { ++ cmp = memcmp_pages(*kpage, tree_page, 1); ++ if (!cmp) { ++ try_merge_with_stable(rmap_item, tree_rmap_item, kpage, ++ tree_page, success1, success2); ++ put_page(tree_page); ++ if (!*success1 && !*success2) ++ goto failed; ++ ++ return stable_node; ++ ++ } else { ++ /* ++ * collision in first level try to create a subtree. ++ * A new node need to be created. ++ */ ++ put_page(tree_page); ++ ++ stable_node_hash_max(stable_node, tree_page, ++ tree_node->hash); ++ hash_max = rmap_item_hash_max(rmap_item, hash); ++ cmp = hash_cmp(hash_max, stable_node->hash_max); ++ ++ parent = &stable_node->node; ++ if (cmp < 0) { ++ new = &parent->rb_left; ++ } else if (cmp > 0) { ++ new = &parent->rb_right; ++ } else { ++ goto failed; ++ } ++ } ++ ++ } else { ++ /* the only stable_node deleted, we reuse its tree_node. ++ */ ++ parent = NULL; ++ new = &tree_node->sub_root.rb_node; ++ } ++ ++ new_snode = new_stable_node(tree_node, *kpage, hash_max); ++ if (!new_snode) ++ goto failed; ++ ++ rb_link_node(&new_snode->node, parent, new); ++ rb_insert_color(&new_snode->node, &tree_node->sub_root); ++ tree_node->count++; ++ *success1 = *success2 = 1; ++ ++ return new_snode; ++ ++failed: ++ return NULL; ++} ++ ++static inline ++struct stable_node *stable_subtree_insert(struct tree_node *tree_node, ++ struct rmap_item *rmap_item, ++ struct rmap_item *tree_rmap_item, ++ struct page **kpage, u32 hash, ++ int *success1, int *success2) ++{ ++ struct page *tree_page; ++ u32 hash_max; ++ struct stable_node *stable_node, *new_snode; ++ struct rb_node *parent, **new; ++ ++research: ++ parent = NULL; ++ new = &tree_node->sub_root.rb_node; ++ BUG_ON(!*new); ++ hash_max = rmap_item_hash_max(rmap_item, hash); ++ while (*new) { ++ int cmp; ++ ++ stable_node = rb_entry(*new, struct stable_node, node); ++ ++ cmp = hash_cmp(hash_max, stable_node->hash_max); ++ ++ if (cmp < 0) { ++ parent = *new; ++ new = &parent->rb_left; ++ } else if (cmp > 0) { ++ parent = *new; ++ new = &parent->rb_right; ++ } else { ++ tree_page = get_uksm_page(stable_node, 1, 0); ++ if (tree_page) { ++ cmp = memcmp_pages(*kpage, tree_page, 1); ++ if (!cmp) { ++ try_merge_with_stable(rmap_item, ++ tree_rmap_item, kpage, ++ tree_page, success1, success2); ++ ++ put_page(tree_page); ++ if (!*success1 && !*success2) ++ goto failed; ++ /* ++ * successfully merged with a stable ++ * node ++ */ ++ return stable_node; ++ } else { ++ put_page(tree_page); ++ goto failed; ++ } ++ } else { ++ /* ++ * stable node may be deleted, ++ * and subtree maybe ++ * restructed, cannot ++ * continue, research it. ++ */ ++ if (tree_node->count) { ++ goto research; ++ } else { ++ /* reuse the tree node*/ ++ parent = NULL; ++ new = &tree_node->sub_root.rb_node; ++ } ++ } ++ } ++ } ++ ++ new_snode = new_stable_node(tree_node, *kpage, hash_max); ++ if (!new_snode) ++ goto failed; ++ ++ rb_link_node(&new_snode->node, parent, new); ++ rb_insert_color(&new_snode->node, &tree_node->sub_root); ++ tree_node->count++; ++ *success1 = *success2 = 1; ++ ++ return new_snode; ++ ++failed: ++ return NULL; ++} ++ ++ ++/** ++ * stable_tree_insert() - try to insert a merged page in unstable tree to ++ * the stable tree ++ * ++ * @kpage: the page need to be inserted ++ * @hash: the current hash of this page ++ * @rmap_item: the rmap_item being scanned ++ * @tree_rmap_item: the rmap_item found on unstable tree ++ * @success1: return if rmap_item is merged ++ * @success2: return if tree_rmap_item is merged ++ * ++ * @return the stable_node on stable tree if at least one ++ * rmap_item is inserted into stable tree, NULL ++ * otherwise. ++ */ ++static struct stable_node * ++stable_tree_insert(struct page **kpage, u32 hash, ++ struct rmap_item *rmap_item, ++ struct rmap_item *tree_rmap_item, ++ int *success1, int *success2) ++{ ++ struct rb_node **new = &root_stable_treep->rb_node; ++ struct rb_node *parent = NULL; ++ struct stable_node *stable_node; ++ struct tree_node *tree_node; ++ u32 hash_max = 0; ++ ++ *success1 = *success2 = 0; ++ ++ while (*new) { ++ int cmp; ++ ++ tree_node = rb_entry(*new, struct tree_node, node); ++ ++ cmp = hash_cmp(hash, tree_node->hash); ++ ++ if (cmp < 0) { ++ parent = *new; ++ new = &parent->rb_left; ++ } else if (cmp > 0) { ++ parent = *new; ++ new = &parent->rb_right; ++ } else ++ break; ++ } ++ ++ if (*new) { ++ if (tree_node->count == 1) { ++ stable_node = first_level_insert(tree_node, rmap_item, ++ tree_rmap_item, kpage, ++ hash, success1, success2); ++ } else { ++ stable_node = stable_subtree_insert(tree_node, ++ rmap_item, tree_rmap_item, kpage, ++ hash, success1, success2); ++ } ++ } else { ++ ++ /* no tree node found */ ++ tree_node = alloc_tree_node(stable_tree_node_listp); ++ if (!tree_node) { ++ stable_node = NULL; ++ goto out; ++ } ++ ++ stable_node = new_stable_node(tree_node, *kpage, hash_max); ++ if (!stable_node) { ++ free_tree_node(tree_node); ++ goto out; ++ } ++ ++ tree_node->hash = hash; ++ rb_link_node(&tree_node->node, parent, new); ++ rb_insert_color(&tree_node->node, root_stable_treep); ++ parent = NULL; ++ new = &tree_node->sub_root.rb_node; ++ ++ rb_link_node(&stable_node->node, parent, new); ++ rb_insert_color(&stable_node->node, &tree_node->sub_root); ++ tree_node->count++; ++ *success1 = *success2 = 1; ++ } ++ ++out: ++ return stable_node; ++} ++ ++ ++/** ++ * get_tree_rmap_item_page() - try to get the page and lock the mmap_sem ++ * ++ * @return 0 on success, -EBUSY if unable to lock the mmap_sem, ++ * -EINVAL if the page mapping has been changed. ++ */ ++static inline int get_tree_rmap_item_page(struct rmap_item *tree_rmap_item) ++{ ++ int err; ++ ++ err = get_mergeable_page_lock_mmap(tree_rmap_item); ++ ++ if (err == -EINVAL) { ++ /* its page map has been changed, remove it */ ++ remove_rmap_item_from_tree(tree_rmap_item); ++ } ++ ++ /* The page is gotten and mmap_sem is locked now. */ ++ return err; ++} ++ ++ ++/** ++ * unstable_tree_search_insert() - search an unstable tree rmap_item with the ++ * same hash value. Get its page and trylock the mmap_sem ++ */ ++static inline ++struct rmap_item *unstable_tree_search_insert(struct rmap_item *rmap_item, ++ u32 hash) ++ ++{ ++ struct rb_node **new = &root_unstable_tree.rb_node; ++ struct rb_node *parent = NULL; ++ struct tree_node *tree_node; ++ u32 hash_max; ++ struct rmap_item *tree_rmap_item; ++ ++ while (*new) { ++ int cmp; ++ ++ tree_node = rb_entry(*new, struct tree_node, node); ++ ++ cmp = hash_cmp(hash, tree_node->hash); ++ ++ if (cmp < 0) { ++ parent = *new; ++ new = &parent->rb_left; ++ } else if (cmp > 0) { ++ parent = *new; ++ new = &parent->rb_right; ++ } else ++ break; ++ } ++ ++ if (*new) { ++ /* got the tree_node */ ++ if (tree_node->count == 1) { ++ tree_rmap_item = rb_entry(tree_node->sub_root.rb_node, ++ struct rmap_item, node); ++ BUG_ON(!tree_rmap_item); ++ ++ goto get_page_out; ++ } ++ ++ /* well, search the collision subtree */ ++ new = &tree_node->sub_root.rb_node; ++ BUG_ON(!*new); ++ hash_max = rmap_item_hash_max(rmap_item, hash); ++ ++ while (*new) { ++ int cmp; ++ ++ tree_rmap_item = rb_entry(*new, struct rmap_item, ++ node); ++ ++ cmp = hash_cmp(hash_max, tree_rmap_item->hash_max); ++ parent = *new; ++ if (cmp < 0) ++ new = &parent->rb_left; ++ else if (cmp > 0) ++ new = &parent->rb_right; ++ else ++ goto get_page_out; ++ } ++ } else { ++ /* alloc a new tree_node */ ++ tree_node = alloc_tree_node(&unstable_tree_node_list); ++ if (!tree_node) ++ return NULL; ++ ++ tree_node->hash = hash; ++ rb_link_node(&tree_node->node, parent, new); ++ rb_insert_color(&tree_node->node, &root_unstable_tree); ++ parent = NULL; ++ new = &tree_node->sub_root.rb_node; ++ } ++ ++ /* did not found even in sub-tree */ ++ rmap_item->tree_node = tree_node; ++ rmap_item->address |= UNSTABLE_FLAG; ++ rmap_item->hash_round = uksm_hash_round; ++ rb_link_node(&rmap_item->node, parent, new); ++ rb_insert_color(&rmap_item->node, &tree_node->sub_root); ++ ++ uksm_pages_unshared++; ++ return NULL; ++ ++get_page_out: ++ if (tree_rmap_item->page == rmap_item->page) ++ return NULL; ++ ++ if (get_tree_rmap_item_page(tree_rmap_item)) ++ return NULL; ++ ++ return tree_rmap_item; ++} ++ ++static void hold_anon_vma(struct rmap_item *rmap_item, ++ struct anon_vma *anon_vma) ++{ ++ rmap_item->anon_vma = anon_vma; ++ get_anon_vma(anon_vma); ++} ++ ++ ++/** ++ * stable_tree_append() - append a rmap_item to a stable node. Deduplication ++ * ratio statistics is done in this function. ++ * ++ */ ++static void stable_tree_append(struct rmap_item *rmap_item, ++ struct stable_node *stable_node, int logdedup) ++{ ++ struct node_vma *node_vma = NULL, *new_node_vma, *node_vma_cont = NULL; ++ unsigned long key = (unsigned long)rmap_item->slot; ++ unsigned long factor = rmap_item->slot->rung->step; ++ ++ BUG_ON(!stable_node); ++ rmap_item->address |= STABLE_FLAG; ++ ++ if (hlist_empty(&stable_node->hlist)) { ++ uksm_pages_shared++; ++ goto node_vma_new; ++ } else { ++ uksm_pages_sharing++; ++ } ++ ++ hlist_for_each_entry(node_vma, &stable_node->hlist, hlist) { ++ if (node_vma->key >= key) ++ break; ++ ++ if (logdedup) { ++ node_vma->slot->pages_bemerged += factor; ++ if (list_empty(&node_vma->slot->dedup_list)) ++ list_add(&node_vma->slot->dedup_list, ++ &vma_slot_dedup); ++ } ++ } ++ ++ if (node_vma) { ++ if (node_vma->key == key) { ++ node_vma_cont = hlist_entry_safe(node_vma->hlist.next, struct node_vma, hlist); ++ goto node_vma_ok; ++ } else if (node_vma->key > key) { ++ node_vma_cont = node_vma; ++ } ++ } ++ ++node_vma_new: ++ /* no same vma already in node, alloc a new node_vma */ ++ new_node_vma = alloc_node_vma(); ++ BUG_ON(!new_node_vma); ++ new_node_vma->head = stable_node; ++ new_node_vma->slot = rmap_item->slot; ++ ++ if (!node_vma) { ++ hlist_add_head(&new_node_vma->hlist, &stable_node->hlist); ++ } else if (node_vma->key != key) { ++ if (node_vma->key < key) ++ hlist_add_after(&node_vma->hlist, &new_node_vma->hlist); ++ else { ++ hlist_add_before(&new_node_vma->hlist, ++ &node_vma->hlist); ++ } ++ ++ } ++ node_vma = new_node_vma; ++ ++node_vma_ok: /* ok, ready to add to the list */ ++ rmap_item->head = node_vma; ++ hlist_add_head(&rmap_item->hlist, &node_vma->rmap_hlist); ++ hold_anon_vma(rmap_item, rmap_item->slot->vma->anon_vma); ++ if (logdedup) { ++ rmap_item->slot->pages_merged++; ++ if (node_vma_cont) { ++ node_vma = node_vma_cont; ++ hlist_for_each_entry_continue(node_vma, hlist) { ++ node_vma->slot->pages_bemerged += factor; ++ if (list_empty(&node_vma->slot->dedup_list)) ++ list_add(&node_vma->slot->dedup_list, ++ &vma_slot_dedup); ++ } ++ } ++ } ++} ++ ++/* ++ * We use break_ksm to break COW on a ksm page: it's a stripped down ++ * ++ * if (get_user_pages(current, mm, addr, 1, 1, 1, &page, NULL) == 1) ++ * put_page(page); ++ * ++ * but taking great care only to touch a ksm page, in a VM_MERGEABLE vma, ++ * in case the application has unmapped and remapped mm,addr meanwhile. ++ * Could a ksm page appear anywhere else? Actually yes, in a VM_PFNMAP ++ * mmap of /dev/mem or /dev/kmem, where we would not want to touch it. ++ */ ++static int break_ksm(struct vm_area_struct *vma, unsigned long addr) ++{ ++ struct page *page; ++ int ret = 0; ++ ++ do { ++ cond_resched(); ++ page = follow_page(vma, addr, FOLL_GET); ++ if (IS_ERR_OR_NULL(page)) ++ break; ++ if (PageKsm(page)) { ++ ret = handle_mm_fault(vma->vm_mm, vma, addr, ++ FAULT_FLAG_WRITE); ++ } else ++ ret = VM_FAULT_WRITE; ++ put_page(page); ++ } while (!(ret & (VM_FAULT_WRITE | VM_FAULT_SIGBUS | VM_FAULT_OOM))); ++ /* ++ * We must loop because handle_mm_fault() may back out if there's ++ * any difficulty e.g. if pte accessed bit gets updated concurrently. ++ * ++ * VM_FAULT_WRITE is what we have been hoping for: it indicates that ++ * COW has been broken, even if the vma does not permit VM_WRITE; ++ * but note that a concurrent fault might break PageKsm for us. ++ * ++ * VM_FAULT_SIGBUS could occur if we race with truncation of the ++ * backing file, which also invalidates anonymous pages: that's ++ * okay, that truncation will have unmapped the PageKsm for us. ++ * ++ * VM_FAULT_OOM: at the time of writing (late July 2009), setting ++ * aside mem_cgroup limits, VM_FAULT_OOM would only be set if the ++ * current task has TIF_MEMDIE set, and will be OOM killed on return ++ * to user; and ksmd, having no mm, would never be chosen for that. ++ * ++ * But if the mm is in a limited mem_cgroup, then the fault may fail ++ * with VM_FAULT_OOM even if the current task is not TIF_MEMDIE; and ++ * even ksmd can fail in this way - though it's usually breaking ksm ++ * just to undo a merge it made a moment before, so unlikely to oom. ++ * ++ * That's a pity: we might therefore have more kernel pages allocated ++ * than we're counting as nodes in the stable tree; but uksm_do_scan ++ * will retry to break_cow on each pass, so should recover the page ++ * in due course. The important thing is to not let VM_MERGEABLE ++ * be cleared while any such pages might remain in the area. ++ */ ++ return (ret & VM_FAULT_OOM) ? -ENOMEM : 0; ++} ++ ++static void break_cow(struct rmap_item *rmap_item) ++{ ++ struct vm_area_struct *vma = rmap_item->slot->vma; ++ struct mm_struct *mm = vma->vm_mm; ++ unsigned long addr = get_rmap_addr(rmap_item); ++ ++ if (uksm_test_exit(mm)) ++ goto out; ++ ++ break_ksm(vma, addr); ++out: ++ return; ++} ++ ++/* ++ * Though it's very tempting to unmerge in_stable_tree(rmap_item)s rather ++ * than check every pte of a given vma, the locking doesn't quite work for ++ * that - an rmap_item is assigned to the stable tree after inserting ksm ++ * page and upping mmap_sem. Nor does it fit with the way we skip dup'ing ++ * rmap_items from parent to child at fork time (so as not to waste time ++ * if exit comes before the next scan reaches it). ++ * ++ * Similarly, although we'd like to remove rmap_items (so updating counts ++ * and freeing memory) when unmerging an area, it's easier to leave that ++ * to the next pass of ksmd - consider, for example, how ksmd might be ++ * in cmp_and_merge_page on one of the rmap_items we would be removing. ++ */ ++inline int unmerge_uksm_pages(struct vm_area_struct *vma, ++ unsigned long start, unsigned long end) ++{ ++ unsigned long addr; ++ int err = 0; ++ ++ for (addr = start; addr < end && !err; addr += PAGE_SIZE) { ++ if (uksm_test_exit(vma->vm_mm)) ++ break; ++ if (signal_pending(current)) ++ err = -ERESTARTSYS; ++ else ++ err = break_ksm(vma, addr); ++ } ++ return err; ++} ++ ++static inline void inc_uksm_pages_scanned(void) ++{ ++ u64 delta; ++ ++ ++ if (uksm_pages_scanned == U64_MAX) { ++ encode_benefit(); ++ ++ delta = uksm_pages_scanned >> pages_scanned_base; ++ ++ if (CAN_OVERFLOW_U64(pages_scanned_stored, delta)) { ++ pages_scanned_stored >>= 1; ++ delta >>= 1; ++ pages_scanned_base++; ++ } ++ ++ pages_scanned_stored += delta; ++ ++ uksm_pages_scanned = uksm_pages_scanned_last = 0; ++ } ++ ++ uksm_pages_scanned++; ++} ++ ++static inline int find_zero_page_hash(int strength, u32 hash) ++{ ++ return (zero_hash_table[strength] == hash); ++} ++ ++static ++int cmp_and_merge_zero_page(struct vm_area_struct *vma, struct page *page) ++{ ++ struct page *zero_page = empty_uksm_zero_page; ++ struct mm_struct *mm = vma->vm_mm; ++ pte_t orig_pte = __pte(0); ++ int err = -EFAULT; ++ ++ if (uksm_test_exit(mm)) ++ goto out; ++ ++ if (PageTransCompound(page) && page_trans_compound_anon_split(page)) ++ goto out; ++ BUG_ON(PageTransCompound(page)); ++ ++ if (!PageAnon(page)) ++ goto out; ++ ++ if (!trylock_page(page)) ++ goto out; ++ ++ if (write_protect_page(vma, page, &orig_pte, 0) == 0) { ++ if (is_page_full_zero(page)) ++ err = replace_page(vma, page, zero_page, orig_pte); ++ } ++ ++ unlock_page(page); ++out: ++ return err; ++} ++ ++/* ++ * cmp_and_merge_page() - first see if page can be merged into the stable ++ * tree; if not, compare hash to previous and if it's the same, see if page ++ * can be inserted into the unstable tree, or merged with a page already there ++ * and both transferred to the stable tree. ++ * ++ * @page: the page that we are searching identical page to. ++ * @rmap_item: the reverse mapping into the virtual address of this page ++ */ ++static void cmp_and_merge_page(struct rmap_item *rmap_item, u32 hash) ++{ ++ struct rmap_item *tree_rmap_item; ++ struct page *page; ++ struct page *kpage = NULL; ++ u32 hash_max; ++ int err; ++ unsigned int success1, success2; ++ struct stable_node *snode; ++ int cmp; ++ struct rb_node *parent = NULL, **new; ++ ++ remove_rmap_item_from_tree(rmap_item); ++ page = rmap_item->page; ++ ++ /* We first start with searching the page inside the stable tree */ ++ kpage = stable_tree_search(rmap_item, hash); ++ if (kpage) { ++ err = try_to_merge_with_uksm_page(rmap_item, kpage, ++ hash); ++ if (!err) { ++ /* ++ * The page was successfully merged, add ++ * its rmap_item to the stable tree. ++ * page lock is needed because it's ++ * racing with try_to_unmap_ksm(), etc. ++ */ ++ lock_page(kpage); ++ snode = page_stable_node(kpage); ++ stable_tree_append(rmap_item, snode, 1); ++ unlock_page(kpage); ++ put_page(kpage); ++ return; /* success */ ++ } ++ put_page(kpage); ++ ++ /* ++ * if it's a collision and it has been search in sub-rbtree ++ * (hash_max != 0), we want to abort, because if it is ++ * successfully merged in unstable tree, the collision trends to ++ * happen again. ++ */ ++ if (err == MERGE_ERR_COLLI && rmap_item->hash_max) ++ return; ++ } ++ ++ tree_rmap_item = ++ unstable_tree_search_insert(rmap_item, hash); ++ if (tree_rmap_item) { ++ err = try_to_merge_two_pages(rmap_item, tree_rmap_item, hash); ++ /* ++ * As soon as we merge this page, we want to remove the ++ * rmap_item of the page we have merged with from the unstable ++ * tree, and insert it instead as new node in the stable tree. ++ */ ++ if (!err) { ++ kpage = page; ++ remove_rmap_item_from_tree(tree_rmap_item); ++ lock_page(kpage); ++ snode = stable_tree_insert(&kpage, hash, ++ rmap_item, tree_rmap_item, ++ &success1, &success2); ++ ++ /* ++ * Do not log dedup for tree item, it's not counted as ++ * scanned in this round. ++ */ ++ if (success2) ++ stable_tree_append(tree_rmap_item, snode, 0); ++ ++ /* ++ * The order of these two stable append is important: ++ * we are scanning rmap_item. ++ */ ++ if (success1) ++ stable_tree_append(rmap_item, snode, 1); ++ ++ /* ++ * The original kpage may be unlocked inside ++ * stable_tree_insert() already. This page ++ * should be unlocked before doing ++ * break_cow(). ++ */ ++ unlock_page(kpage); ++ ++ if (!success1) ++ break_cow(rmap_item); ++ ++ if (!success2) ++ break_cow(tree_rmap_item); ++ ++ } else if (err == MERGE_ERR_COLLI) { ++ BUG_ON(tree_rmap_item->tree_node->count > 1); ++ ++ rmap_item_hash_max(tree_rmap_item, ++ tree_rmap_item->tree_node->hash); ++ ++ hash_max = rmap_item_hash_max(rmap_item, hash); ++ cmp = hash_cmp(hash_max, tree_rmap_item->hash_max); ++ parent = &tree_rmap_item->node; ++ if (cmp < 0) ++ new = &parent->rb_left; ++ else if (cmp > 0) ++ new = &parent->rb_right; ++ else ++ goto put_up_out; ++ ++ rmap_item->tree_node = tree_rmap_item->tree_node; ++ rmap_item->address |= UNSTABLE_FLAG; ++ rmap_item->hash_round = uksm_hash_round; ++ rb_link_node(&rmap_item->node, parent, new); ++ rb_insert_color(&rmap_item->node, ++ &tree_rmap_item->tree_node->sub_root); ++ rmap_item->tree_node->count++; ++ } else { ++ /* ++ * either one of the page has changed or they collide ++ * at the max hash, we consider them as ill items. ++ */ ++ remove_rmap_item_from_tree(tree_rmap_item); ++ } ++put_up_out: ++ put_page(tree_rmap_item->page); ++ up_read(&tree_rmap_item->slot->vma->vm_mm->mmap_sem); ++ } ++} ++ ++ ++ ++ ++static inline unsigned long get_pool_index(struct vma_slot *slot, ++ unsigned long index) ++{ ++ unsigned long pool_index; ++ ++ pool_index = (sizeof(struct rmap_list_entry *) * index) >> PAGE_SHIFT; ++ if (pool_index >= slot->pool_size) ++ BUG(); ++ return pool_index; ++} ++ ++static inline unsigned long index_page_offset(unsigned long index) ++{ ++ return offset_in_page(sizeof(struct rmap_list_entry *) * index); ++} ++ ++static inline ++struct rmap_list_entry *get_rmap_list_entry(struct vma_slot *slot, ++ unsigned long index, int need_alloc) ++{ ++ unsigned long pool_index; ++ struct page *page; ++ void *addr; ++ ++ ++ pool_index = get_pool_index(slot, index); ++ if (!slot->rmap_list_pool[pool_index]) { ++ if (!need_alloc) ++ return NULL; ++ ++ page = alloc_page(GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN); ++ if (!page) ++ return NULL; ++ ++ slot->rmap_list_pool[pool_index] = page; ++ } ++ ++ addr = kmap(slot->rmap_list_pool[pool_index]); ++ addr += index_page_offset(index); ++ ++ return addr; ++} ++ ++static inline void put_rmap_list_entry(struct vma_slot *slot, ++ unsigned long index) ++{ ++ unsigned long pool_index; ++ ++ pool_index = get_pool_index(slot, index); ++ BUG_ON(!slot->rmap_list_pool[pool_index]); ++ kunmap(slot->rmap_list_pool[pool_index]); ++} ++ ++static inline int entry_is_new(struct rmap_list_entry *entry) ++{ ++ return !entry->item; ++} ++ ++static inline unsigned long get_index_orig_addr(struct vma_slot *slot, ++ unsigned long index) ++{ ++ return slot->vma->vm_start + (index << PAGE_SHIFT); ++} ++ ++static inline unsigned long get_entry_address(struct rmap_list_entry *entry) ++{ ++ unsigned long addr; ++ ++ if (is_addr(entry->addr)) ++ addr = get_clean_addr(entry->addr); ++ else if (entry->item) ++ addr = get_rmap_addr(entry->item); ++ else ++ BUG(); ++ ++ return addr; ++} ++ ++static inline struct rmap_item *get_entry_item(struct rmap_list_entry *entry) ++{ ++ if (is_addr(entry->addr)) ++ return NULL; ++ ++ return entry->item; ++} ++ ++static inline void inc_rmap_list_pool_count(struct vma_slot *slot, ++ unsigned long index) ++{ ++ unsigned long pool_index; ++ ++ pool_index = get_pool_index(slot, index); ++ BUG_ON(!slot->rmap_list_pool[pool_index]); ++ slot->pool_counts[pool_index]++; ++} ++ ++static inline void dec_rmap_list_pool_count(struct vma_slot *slot, ++ unsigned long index) ++{ ++ unsigned long pool_index; ++ ++ pool_index = get_pool_index(slot, index); ++ BUG_ON(!slot->rmap_list_pool[pool_index]); ++ BUG_ON(!slot->pool_counts[pool_index]); ++ slot->pool_counts[pool_index]--; ++} ++ ++static inline int entry_has_rmap(struct rmap_list_entry *entry) ++{ ++ return !is_addr(entry->addr) && entry->item; ++} ++ ++static inline void swap_entries(struct rmap_list_entry *entry1, ++ unsigned long index1, ++ struct rmap_list_entry *entry2, ++ unsigned long index2) ++{ ++ struct rmap_list_entry tmp; ++ ++ /* swapping two new entries is meaningless */ ++ BUG_ON(entry_is_new(entry1) && entry_is_new(entry2)); ++ ++ tmp = *entry1; ++ *entry1 = *entry2; ++ *entry2 = tmp; ++ ++ if (entry_has_rmap(entry1)) ++ entry1->item->entry_index = index1; ++ ++ if (entry_has_rmap(entry2)) ++ entry2->item->entry_index = index2; ++ ++ if (entry_has_rmap(entry1) && !entry_has_rmap(entry2)) { ++ inc_rmap_list_pool_count(entry1->item->slot, index1); ++ dec_rmap_list_pool_count(entry1->item->slot, index2); ++ } else if (!entry_has_rmap(entry1) && entry_has_rmap(entry2)) { ++ inc_rmap_list_pool_count(entry2->item->slot, index2); ++ dec_rmap_list_pool_count(entry2->item->slot, index1); ++ } ++} ++ ++static inline void free_entry_item(struct rmap_list_entry *entry) ++{ ++ unsigned long index; ++ struct rmap_item *item; ++ ++ if (!is_addr(entry->addr)) { ++ BUG_ON(!entry->item); ++ item = entry->item; ++ entry->addr = get_rmap_addr(item); ++ set_is_addr(entry->addr); ++ index = item->entry_index; ++ remove_rmap_item_from_tree(item); ++ dec_rmap_list_pool_count(item->slot, index); ++ free_rmap_item(item); ++ } ++} ++ ++static inline int pool_entry_boundary(unsigned long index) ++{ ++ unsigned long linear_addr; ++ ++ linear_addr = sizeof(struct rmap_list_entry *) * index; ++ return index && !offset_in_page(linear_addr); ++} ++ ++static inline void try_free_last_pool(struct vma_slot *slot, ++ unsigned long index) ++{ ++ unsigned long pool_index; ++ ++ pool_index = get_pool_index(slot, index); ++ if (slot->rmap_list_pool[pool_index] && ++ !slot->pool_counts[pool_index]) { ++ __free_page(slot->rmap_list_pool[pool_index]); ++ slot->rmap_list_pool[pool_index] = NULL; ++ slot->flags |= UKSM_SLOT_NEED_SORT; ++ } ++ ++} ++ ++static inline unsigned long vma_item_index(struct vm_area_struct *vma, ++ struct rmap_item *item) ++{ ++ return (get_rmap_addr(item) - vma->vm_start) >> PAGE_SHIFT; ++} ++ ++static int within_same_pool(struct vma_slot *slot, ++ unsigned long i, unsigned long j) ++{ ++ unsigned long pool_i, pool_j; ++ ++ pool_i = get_pool_index(slot, i); ++ pool_j = get_pool_index(slot, j); ++ ++ return (pool_i == pool_j); ++} ++ ++static void sort_rmap_entry_list(struct vma_slot *slot) ++{ ++ unsigned long i, j; ++ struct rmap_list_entry *entry, *swap_entry; ++ ++ entry = get_rmap_list_entry(slot, 0, 0); ++ for (i = 0; i < slot->pages; ) { ++ ++ if (!entry) ++ goto skip_whole_pool; ++ ++ if (entry_is_new(entry)) ++ goto next_entry; ++ ++ if (is_addr(entry->addr)) { ++ entry->addr = 0; ++ goto next_entry; ++ } ++ ++ j = vma_item_index(slot->vma, entry->item); ++ if (j == i) ++ goto next_entry; ++ ++ if (within_same_pool(slot, i, j)) ++ swap_entry = entry + j - i; ++ else ++ swap_entry = get_rmap_list_entry(slot, j, 1); ++ ++ swap_entries(entry, i, swap_entry, j); ++ if (!within_same_pool(slot, i, j)) ++ put_rmap_list_entry(slot, j); ++ continue; ++ ++skip_whole_pool: ++ i += PAGE_SIZE / sizeof(*entry); ++ if (i < slot->pages) ++ entry = get_rmap_list_entry(slot, i, 0); ++ continue; ++ ++next_entry: ++ if (i >= slot->pages - 1 || ++ !within_same_pool(slot, i, i + 1)) { ++ put_rmap_list_entry(slot, i); ++ if (i + 1 < slot->pages) ++ entry = get_rmap_list_entry(slot, i + 1, 0); ++ } else ++ entry++; ++ i++; ++ continue; ++ } ++ ++ /* free empty pool entries which contain no rmap_item */ ++ /* CAN be simplied to based on only pool_counts when bug freed !!!!! */ ++ for (i = 0; i < slot->pool_size; i++) { ++ unsigned char has_rmap; ++ void *addr; ++ ++ if (!slot->rmap_list_pool[i]) ++ continue; ++ ++ has_rmap = 0; ++ addr = kmap(slot->rmap_list_pool[i]); ++ BUG_ON(!addr); ++ for (j = 0; j < PAGE_SIZE / sizeof(*entry); j++) { ++ entry = (struct rmap_list_entry *)addr + j; ++ if (is_addr(entry->addr)) ++ continue; ++ if (!entry->item) ++ continue; ++ has_rmap = 1; ++ } ++ kunmap(slot->rmap_list_pool[i]); ++ if (!has_rmap) { ++ BUG_ON(slot->pool_counts[i]); ++ __free_page(slot->rmap_list_pool[i]); ++ slot->rmap_list_pool[i] = NULL; ++ } ++ } ++ ++ slot->flags &= ~UKSM_SLOT_NEED_SORT; ++} ++ ++/* ++ * vma_fully_scanned() - if all the pages in this slot have been scanned. ++ */ ++static inline int vma_fully_scanned(struct vma_slot *slot) ++{ ++ return slot->pages_scanned == slot->pages; ++} ++ ++/** ++ * get_next_rmap_item() - Get the next rmap_item in a vma_slot according to ++ * its random permutation. This function is embedded with the random ++ * permutation index management code. ++ */ ++static struct rmap_item *get_next_rmap_item(struct vma_slot *slot, u32 *hash) ++{ ++ unsigned long rand_range, addr, swap_index, scan_index; ++ struct rmap_item *item = NULL; ++ struct rmap_list_entry *scan_entry, *swap_entry = NULL; ++ struct page *page; ++ ++ scan_index = swap_index = slot->pages_scanned % slot->pages; ++ ++ if (pool_entry_boundary(scan_index)) ++ try_free_last_pool(slot, scan_index - 1); ++ ++ if (vma_fully_scanned(slot)) { ++ if (slot->flags & UKSM_SLOT_NEED_SORT) ++ slot->flags |= UKSM_SLOT_NEED_RERAND; ++ else ++ slot->flags &= ~UKSM_SLOT_NEED_RERAND; ++ if (slot->flags & UKSM_SLOT_NEED_SORT) ++ sort_rmap_entry_list(slot); ++ } ++ ++ scan_entry = get_rmap_list_entry(slot, scan_index, 1); ++ if (!scan_entry) ++ return NULL; ++ ++ if (entry_is_new(scan_entry)) { ++ scan_entry->addr = get_index_orig_addr(slot, scan_index); ++ set_is_addr(scan_entry->addr); ++ } ++ ++ if (slot->flags & UKSM_SLOT_NEED_RERAND) { ++ rand_range = slot->pages - scan_index; ++ BUG_ON(!rand_range); ++ swap_index = scan_index + (prandom_u32() % rand_range); ++ } ++ ++ if (swap_index != scan_index) { ++ swap_entry = get_rmap_list_entry(slot, swap_index, 1); ++ if (entry_is_new(swap_entry)) { ++ swap_entry->addr = get_index_orig_addr(slot, ++ swap_index); ++ set_is_addr(swap_entry->addr); ++ } ++ swap_entries(scan_entry, scan_index, swap_entry, swap_index); ++ } ++ ++ addr = get_entry_address(scan_entry); ++ item = get_entry_item(scan_entry); ++ BUG_ON(addr > slot->vma->vm_end || addr < slot->vma->vm_start); ++ ++ page = follow_page(slot->vma, addr, FOLL_GET); ++ if (IS_ERR_OR_NULL(page)) ++ goto nopage; ++ ++ if (!PageAnon(page) && !page_trans_compound_anon(page)) ++ goto putpage; ++ ++ /*check is zero_page pfn or uksm_zero_page*/ ++ if ((page_to_pfn(page) == zero_pfn) ++ || (page_to_pfn(page) == uksm_zero_pfn)) ++ goto putpage; ++ ++ flush_anon_page(slot->vma, page, addr); ++ flush_dcache_page(page); ++ ++ ++ *hash = page_hash(page, hash_strength, 1); ++ inc_uksm_pages_scanned(); ++ /*if the page content all zero, re-map to zero-page*/ ++ if (find_zero_page_hash(hash_strength, *hash)) { ++ if (!cmp_and_merge_zero_page(slot->vma, page)) { ++ slot->pages_merged++; ++ __inc_zone_page_state(page, NR_UKSM_ZERO_PAGES); ++ dec_mm_counter(slot->mm, MM_ANONPAGES); ++ ++ /* For full-zero pages, no need to create rmap item */ ++ goto putpage; ++ } else { ++ inc_rshash_neg(memcmp_cost / 2); ++ } ++ } ++ ++ if (!item) { ++ item = alloc_rmap_item(); ++ if (item) { ++ /* It has already been zeroed */ ++ item->slot = slot; ++ item->address = addr; ++ item->entry_index = scan_index; ++ scan_entry->item = item; ++ inc_rmap_list_pool_count(slot, scan_index); ++ } else ++ goto putpage; ++ } ++ ++ BUG_ON(item->slot != slot); ++ /* the page may have changed */ ++ item->page = page; ++ put_rmap_list_entry(slot, scan_index); ++ if (swap_entry) ++ put_rmap_list_entry(slot, swap_index); ++ return item; ++ ++putpage: ++ put_page(page); ++ page = NULL; ++nopage: ++ /* no page, store addr back and free rmap_item if possible */ ++ free_entry_item(scan_entry); ++ put_rmap_list_entry(slot, scan_index); ++ if (swap_entry) ++ put_rmap_list_entry(slot, swap_index); ++ return NULL; ++} ++ ++static inline int in_stable_tree(struct rmap_item *rmap_item) ++{ ++ return rmap_item->address & STABLE_FLAG; ++} ++ ++/** ++ * scan_vma_one_page() - scan the next page in a vma_slot. Called with ++ * mmap_sem locked. ++ */ ++static noinline void scan_vma_one_page(struct vma_slot *slot) ++{ ++ u32 hash; ++ struct mm_struct *mm; ++ struct rmap_item *rmap_item = NULL; ++ struct vm_area_struct *vma = slot->vma; ++ ++ mm = vma->vm_mm; ++ BUG_ON(!mm); ++ BUG_ON(!slot); ++ ++ rmap_item = get_next_rmap_item(slot, &hash); ++ if (!rmap_item) ++ goto out1; ++ ++ if (PageKsm(rmap_item->page) && in_stable_tree(rmap_item)) ++ goto out2; ++ ++ cmp_and_merge_page(rmap_item, hash); ++out2: ++ put_page(rmap_item->page); ++out1: ++ slot->pages_scanned++; ++ if (slot->fully_scanned_round != fully_scanned_round) ++ scanned_virtual_pages++; ++ ++ if (vma_fully_scanned(slot)) ++ slot->fully_scanned_round = fully_scanned_round; ++} ++ ++static inline unsigned long rung_get_pages(struct scan_rung *rung) ++{ ++ struct slot_tree_node *node; ++ ++ if (!rung->vma_root.rnode) ++ return 0; ++ ++ node = container_of(rung->vma_root.rnode, struct slot_tree_node, snode); ++ ++ return node->size; ++} ++ ++#define RUNG_SAMPLED_MIN 3 ++ ++static inline ++void uksm_calc_rung_step(struct scan_rung *rung, ++ unsigned long page_time, unsigned long ratio) ++{ ++ unsigned long sampled, pages; ++ ++ /* will be fully scanned ? */ ++ if (!rung->cover_msecs) { ++ rung->step = 1; ++ return; ++ } ++ ++ sampled = rung->cover_msecs * (NSEC_PER_MSEC / TIME_RATIO_SCALE) ++ * ratio / page_time; ++ ++ /* ++ * Before we finsish a scan round and expensive per-round jobs, ++ * we need to have a chance to estimate the per page time. So ++ * the sampled number can not be too small. ++ */ ++ if (sampled < RUNG_SAMPLED_MIN) ++ sampled = RUNG_SAMPLED_MIN; ++ ++ pages = rung_get_pages(rung); ++ if (likely(pages > sampled)) ++ rung->step = pages / sampled; ++ else ++ rung->step = 1; ++} ++ ++static inline int step_need_recalc(struct scan_rung *rung) ++{ ++ unsigned long pages, stepmax; ++ ++ pages = rung_get_pages(rung); ++ stepmax = pages / RUNG_SAMPLED_MIN; ++ ++ return pages && (rung->step > pages || ++ (stepmax && rung->step > stepmax)); ++} ++ ++static inline ++void reset_current_scan(struct scan_rung *rung, int finished, int step_recalc) ++{ ++ struct vma_slot *slot; ++ ++ if (finished) ++ rung->flags |= UKSM_RUNG_ROUND_FINISHED; ++ ++ if (step_recalc || step_need_recalc(rung)) { ++ uksm_calc_rung_step(rung, uksm_ema_page_time, rung->cpu_ratio); ++ BUG_ON(step_need_recalc(rung)); ++ } ++ ++ slot_iter_index = prandom_u32() % rung->step; ++ BUG_ON(!rung->vma_root.rnode); ++ slot = sradix_tree_next(&rung->vma_root, NULL, 0, slot_iter); ++ BUG_ON(!slot); ++ ++ rung->current_scan = slot; ++ rung->current_offset = slot_iter_index; ++} ++ ++static inline struct sradix_tree_root *slot_get_root(struct vma_slot *slot) ++{ ++ return &slot->rung->vma_root; ++} ++ ++/* ++ * return if resetted. ++ */ ++static int advance_current_scan(struct scan_rung *rung) ++{ ++ unsigned short n; ++ struct vma_slot *slot, *next = NULL; ++ ++ BUG_ON(!rung->vma_root.num); ++ ++ slot = rung->current_scan; ++ n = (slot->pages - rung->current_offset) % rung->step; ++ slot_iter_index = rung->step - n; ++ next = sradix_tree_next(&rung->vma_root, slot->snode, ++ slot->sindex, slot_iter); ++ ++ if (next) { ++ rung->current_offset = slot_iter_index; ++ rung->current_scan = next; ++ return 0; ++ } else { ++ reset_current_scan(rung, 1, 0); ++ return 1; ++ } ++} ++ ++static inline void rung_rm_slot(struct vma_slot *slot) ++{ ++ struct scan_rung *rung = slot->rung; ++ struct sradix_tree_root *root; ++ ++ if (rung->current_scan == slot) ++ advance_current_scan(rung); ++ ++ root = slot_get_root(slot); ++ sradix_tree_delete_from_leaf(root, slot->snode, slot->sindex); ++ slot->snode = NULL; ++ if (step_need_recalc(rung)) { ++ uksm_calc_rung_step(rung, uksm_ema_page_time, rung->cpu_ratio); ++ BUG_ON(step_need_recalc(rung)); ++ } ++ ++ /* In case advance_current_scan loop back to this slot again */ ++ if (rung->vma_root.num && rung->current_scan == slot) ++ reset_current_scan(slot->rung, 1, 0); ++} ++ ++static inline void rung_add_new_slots(struct scan_rung *rung, ++ struct vma_slot **slots, unsigned long num) ++{ ++ int err; ++ struct vma_slot *slot; ++ unsigned long i; ++ struct sradix_tree_root *root = &rung->vma_root; ++ ++ err = sradix_tree_enter(root, (void **)slots, num); ++ BUG_ON(err); ++ ++ for (i = 0; i < num; i++) { ++ slot = slots[i]; ++ slot->rung = rung; ++ BUG_ON(vma_fully_scanned(slot)); ++ } ++ ++ if (rung->vma_root.num == num) ++ reset_current_scan(rung, 0, 1); ++} ++ ++static inline int rung_add_one_slot(struct scan_rung *rung, ++ struct vma_slot *slot) ++{ ++ int err; ++ ++ err = sradix_tree_enter(&rung->vma_root, (void **)&slot, 1); ++ if (err) ++ return err; ++ ++ slot->rung = rung; ++ if (rung->vma_root.num == 1) ++ reset_current_scan(rung, 0, 1); ++ ++ return 0; ++} ++ ++/* ++ * Return true if the slot is deleted from its rung. ++ */ ++static inline int vma_rung_enter(struct vma_slot *slot, struct scan_rung *rung) ++{ ++ struct scan_rung *old_rung = slot->rung; ++ int err; ++ ++ if (old_rung == rung) ++ return 0; ++ ++ rung_rm_slot(slot); ++ err = rung_add_one_slot(rung, slot); ++ if (err) { ++ err = rung_add_one_slot(old_rung, slot); ++ WARN_ON(err); /* OOPS, badly OOM, we lost this slot */ ++ } ++ ++ return 1; ++} ++ ++static inline int vma_rung_up(struct vma_slot *slot) ++{ ++ struct scan_rung *rung; ++ ++ rung = slot->rung; ++ if (slot->rung != &uksm_scan_ladder[SCAN_LADDER_SIZE-1]) ++ rung++; ++ ++ return vma_rung_enter(slot, rung); ++} ++ ++static inline int vma_rung_down(struct vma_slot *slot) ++{ ++ struct scan_rung *rung; ++ ++ rung = slot->rung; ++ if (slot->rung != &uksm_scan_ladder[0]) ++ rung--; ++ ++ return vma_rung_enter(slot, rung); ++} ++ ++/** ++ * cal_dedup_ratio() - Calculate the deduplication ratio for this slot. ++ */ ++static unsigned long cal_dedup_ratio(struct vma_slot *slot) ++{ ++ unsigned long ret; ++ ++ BUG_ON(slot->pages_scanned == slot->last_scanned); ++ ++ ret = slot->pages_merged; ++ ++ /* Thrashing area filtering */ ++ if (ret && uksm_thrash_threshold) { ++ if (slot->pages_cowed * 100 / slot->pages_merged ++ > uksm_thrash_threshold) { ++ ret = 0; ++ } else { ++ ret = slot->pages_merged - slot->pages_cowed; ++ } ++ } ++ ++ return ret; ++} ++ ++/** ++ * cal_dedup_ratio() - Calculate the deduplication ratio for this slot. ++ */ ++static unsigned long cal_dedup_ratio_old(struct vma_slot *slot) ++{ ++ unsigned long ret; ++ unsigned long pages_scanned; ++ ++ pages_scanned = slot->pages_scanned; ++ if (!pages_scanned) { ++ if (uksm_thrash_threshold) ++ return 0; ++ else ++ pages_scanned = slot->pages_scanned; ++ } ++ ++ ret = slot->pages_bemerged * 100 / pages_scanned; ++ ++ /* Thrashing area filtering */ ++ if (ret && uksm_thrash_threshold) { ++ if (slot->pages_cowed * 100 / slot->pages_bemerged ++ > uksm_thrash_threshold) { ++ ret = 0; ++ } else { ++ ret = slot->pages_bemerged - slot->pages_cowed; ++ } ++ } ++ ++ return ret; ++} ++ ++/** ++ * stable_node_reinsert() - When the hash_strength has been adjusted, the ++ * stable tree need to be restructured, this is the function re-inserting the ++ * stable node. ++ */ ++static inline void stable_node_reinsert(struct stable_node *new_node, ++ struct page *page, ++ struct rb_root *root_treep, ++ struct list_head *tree_node_listp, ++ u32 hash) ++{ ++ struct rb_node **new = &root_treep->rb_node; ++ struct rb_node *parent = NULL; ++ struct stable_node *stable_node; ++ struct tree_node *tree_node; ++ struct page *tree_page; ++ int cmp; ++ ++ while (*new) { ++ int cmp; ++ ++ tree_node = rb_entry(*new, struct tree_node, node); ++ ++ cmp = hash_cmp(hash, tree_node->hash); ++ ++ if (cmp < 0) { ++ parent = *new; ++ new = &parent->rb_left; ++ } else if (cmp > 0) { ++ parent = *new; ++ new = &parent->rb_right; ++ } else ++ break; ++ } ++ ++ if (*new) { ++ /* find a stable tree node with same first level hash value */ ++ stable_node_hash_max(new_node, page, hash); ++ if (tree_node->count == 1) { ++ stable_node = rb_entry(tree_node->sub_root.rb_node, ++ struct stable_node, node); ++ tree_page = get_uksm_page(stable_node, 1, 0); ++ if (tree_page) { ++ stable_node_hash_max(stable_node, ++ tree_page, hash); ++ put_page(tree_page); ++ ++ /* prepare for stable node insertion */ ++ ++ cmp = hash_cmp(new_node->hash_max, ++ stable_node->hash_max); ++ parent = &stable_node->node; ++ if (cmp < 0) ++ new = &parent->rb_left; ++ else if (cmp > 0) ++ new = &parent->rb_right; ++ else ++ goto failed; ++ ++ goto add_node; ++ } else { ++ /* the only stable_node deleted, the tree node ++ * was not deleted. ++ */ ++ goto tree_node_reuse; ++ } ++ } ++ ++ /* well, search the collision subtree */ ++ new = &tree_node->sub_root.rb_node; ++ parent = NULL; ++ BUG_ON(!*new); ++ while (*new) { ++ int cmp; ++ ++ stable_node = rb_entry(*new, struct stable_node, node); ++ ++ cmp = hash_cmp(new_node->hash_max, ++ stable_node->hash_max); ++ ++ if (cmp < 0) { ++ parent = *new; ++ new = &parent->rb_left; ++ } else if (cmp > 0) { ++ parent = *new; ++ new = &parent->rb_right; ++ } else { ++ /* oh, no, still a collision */ ++ goto failed; ++ } ++ } ++ ++ goto add_node; ++ } ++ ++ /* no tree node found */ ++ tree_node = alloc_tree_node(tree_node_listp); ++ if (!tree_node) { ++ printk(KERN_ERR "UKSM: memory allocation error!\n"); ++ goto failed; ++ } else { ++ tree_node->hash = hash; ++ rb_link_node(&tree_node->node, parent, new); ++ rb_insert_color(&tree_node->node, root_treep); ++ ++tree_node_reuse: ++ /* prepare for stable node insertion */ ++ parent = NULL; ++ new = &tree_node->sub_root.rb_node; ++ } ++ ++add_node: ++ rb_link_node(&new_node->node, parent, new); ++ rb_insert_color(&new_node->node, &tree_node->sub_root); ++ new_node->tree_node = tree_node; ++ tree_node->count++; ++ return; ++ ++failed: ++ /* This can only happen when two nodes have collided ++ * in two levels. ++ */ ++ new_node->tree_node = NULL; ++ return; ++} ++ ++static inline void free_all_tree_nodes(struct list_head *list) ++{ ++ struct tree_node *node, *tmp; ++ ++ list_for_each_entry_safe(node, tmp, list, all_list) { ++ free_tree_node(node); ++ } ++} ++ ++/** ++ * stable_tree_delta_hash() - Delta hash the stable tree from previous hash ++ * strength to the current hash_strength. It re-structures the hole tree. ++ */ ++static inline void stable_tree_delta_hash(u32 prev_hash_strength) ++{ ++ struct stable_node *node, *tmp; ++ struct rb_root *root_new_treep; ++ struct list_head *new_tree_node_listp; ++ ++ stable_tree_index = (stable_tree_index + 1) % 2; ++ root_new_treep = &root_stable_tree[stable_tree_index]; ++ new_tree_node_listp = &stable_tree_node_list[stable_tree_index]; ++ *root_new_treep = RB_ROOT; ++ BUG_ON(!list_empty(new_tree_node_listp)); ++ ++ /* ++ * we need to be safe, the node could be removed by get_uksm_page() ++ */ ++ list_for_each_entry_safe(node, tmp, &stable_node_list, all_list) { ++ void *addr; ++ struct page *node_page; ++ u32 hash; ++ ++ /* ++ * We are completely re-structuring the stable nodes to a new ++ * stable tree. We don't want to touch the old tree unlinks and ++ * old tree_nodes. The old tree_nodes will be freed at once. ++ */ ++ node_page = get_uksm_page(node, 0, 0); ++ if (!node_page) ++ continue; ++ ++ if (node->tree_node) { ++ hash = node->tree_node->hash; ++ ++ addr = kmap_atomic(node_page); ++ ++ hash = delta_hash(addr, prev_hash_strength, ++ hash_strength, hash); ++ kunmap_atomic(addr); ++ } else { ++ /* ++ *it was not inserted to rbtree due to collision in last ++ *round scan. ++ */ ++ hash = page_hash(node_page, hash_strength, 0); ++ } ++ ++ stable_node_reinsert(node, node_page, root_new_treep, ++ new_tree_node_listp, hash); ++ put_page(node_page); ++ } ++ ++ root_stable_treep = root_new_treep; ++ free_all_tree_nodes(stable_tree_node_listp); ++ BUG_ON(!list_empty(stable_tree_node_listp)); ++ stable_tree_node_listp = new_tree_node_listp; ++} ++ ++static inline void inc_hash_strength(unsigned long delta) ++{ ++ hash_strength += 1 << delta; ++ if (hash_strength > HASH_STRENGTH_MAX) ++ hash_strength = HASH_STRENGTH_MAX; ++} ++ ++static inline void dec_hash_strength(unsigned long delta) ++{ ++ unsigned long change = 1 << delta; ++ ++ if (hash_strength <= change + 1) ++ hash_strength = 1; ++ else ++ hash_strength -= change; ++} ++ ++static inline void inc_hash_strength_delta(void) ++{ ++ hash_strength_delta++; ++ if (hash_strength_delta > HASH_STRENGTH_DELTA_MAX) ++ hash_strength_delta = HASH_STRENGTH_DELTA_MAX; ++} ++ ++/* ++static inline unsigned long get_current_neg_ratio(void) ++{ ++ if (!rshash_pos || rshash_neg > rshash_pos) ++ return 100; ++ ++ return div64_u64(100 * rshash_neg , rshash_pos); ++} ++*/ ++ ++static inline unsigned long get_current_neg_ratio(void) ++{ ++ u64 pos = benefit.pos; ++ u64 neg = benefit.neg; ++ ++ if (!neg) ++ return 0; ++ ++ if (!pos || neg > pos) ++ return 100; ++ ++ if (neg > div64_u64(U64_MAX, 100)) ++ pos = div64_u64(pos, 100); ++ else ++ neg *= 100; ++ ++ return div64_u64(neg, pos); ++} ++ ++static inline unsigned long get_current_benefit(void) ++{ ++ u64 pos = benefit.pos; ++ u64 neg = benefit.neg; ++ u64 scanned = benefit.scanned; ++ ++ if (neg > pos) ++ return 0; ++ ++ return div64_u64((pos - neg), scanned); ++} ++ ++static inline int judge_rshash_direction(void) ++{ ++ u64 current_neg_ratio, stable_benefit; ++ u64 current_benefit, delta = 0; ++ int ret = STILL; ++ ++ /* Try to probe a value after the boot, and in case the system ++ are still for a long time. */ ++ if ((fully_scanned_round & 0xFFULL) == 10) { ++ ret = OBSCURE; ++ goto out; ++ } ++ ++ current_neg_ratio = get_current_neg_ratio(); ++ ++ if (current_neg_ratio == 0) { ++ rshash_neg_cont_zero++; ++ if (rshash_neg_cont_zero > 2) ++ return GO_DOWN; ++ else ++ return STILL; ++ } ++ rshash_neg_cont_zero = 0; ++ ++ if (current_neg_ratio > 90) { ++ ret = GO_UP; ++ goto out; ++ } ++ ++ current_benefit = get_current_benefit(); ++ stable_benefit = rshash_state.stable_benefit; ++ ++ if (!stable_benefit) { ++ ret = OBSCURE; ++ goto out; ++ } ++ ++ if (current_benefit > stable_benefit) ++ delta = current_benefit - stable_benefit; ++ else if (current_benefit < stable_benefit) ++ delta = stable_benefit - current_benefit; ++ ++ delta = div64_u64(100 * delta , stable_benefit); ++ ++ if (delta > 50) { ++ rshash_cont_obscure++; ++ if (rshash_cont_obscure > 2) ++ return OBSCURE; ++ else ++ return STILL; ++ } ++ ++out: ++ rshash_cont_obscure = 0; ++ return ret; ++} ++ ++/** ++ * rshash_adjust() - The main function to control the random sampling state ++ * machine for hash strength adapting. ++ * ++ * return true if hash_strength has changed. ++ */ ++static inline int rshash_adjust(void) ++{ ++ unsigned long prev_hash_strength = hash_strength; ++ ++ if (!encode_benefit()) ++ return 0; ++ ++ switch (rshash_state.state) { ++ case RSHASH_STILL: ++ switch (judge_rshash_direction()) { ++ case GO_UP: ++ if (rshash_state.pre_direct == GO_DOWN) ++ hash_strength_delta = 0; ++ ++ inc_hash_strength(hash_strength_delta); ++ inc_hash_strength_delta(); ++ rshash_state.stable_benefit = get_current_benefit(); ++ rshash_state.pre_direct = GO_UP; ++ break; ++ ++ case GO_DOWN: ++ if (rshash_state.pre_direct == GO_UP) ++ hash_strength_delta = 0; ++ ++ dec_hash_strength(hash_strength_delta); ++ inc_hash_strength_delta(); ++ rshash_state.stable_benefit = get_current_benefit(); ++ rshash_state.pre_direct = GO_DOWN; ++ break; ++ ++ case OBSCURE: ++ rshash_state.stable_point = hash_strength; ++ rshash_state.turn_point_down = hash_strength; ++ rshash_state.turn_point_up = hash_strength; ++ rshash_state.turn_benefit_down = get_current_benefit(); ++ rshash_state.turn_benefit_up = get_current_benefit(); ++ rshash_state.lookup_window_index = 0; ++ rshash_state.state = RSHASH_TRYDOWN; ++ dec_hash_strength(hash_strength_delta); ++ inc_hash_strength_delta(); ++ break; ++ ++ case STILL: ++ break; ++ default: ++ BUG(); ++ } ++ break; ++ ++ case RSHASH_TRYDOWN: ++ if (rshash_state.lookup_window_index++ % 5 == 0) ++ rshash_state.below_count = 0; ++ ++ if (get_current_benefit() < rshash_state.stable_benefit) ++ rshash_state.below_count++; ++ else if (get_current_benefit() > ++ rshash_state.turn_benefit_down) { ++ rshash_state.turn_point_down = hash_strength; ++ rshash_state.turn_benefit_down = get_current_benefit(); ++ } ++ ++ if (rshash_state.below_count >= 3 || ++ judge_rshash_direction() == GO_UP || ++ hash_strength == 1) { ++ hash_strength = rshash_state.stable_point; ++ hash_strength_delta = 0; ++ inc_hash_strength(hash_strength_delta); ++ inc_hash_strength_delta(); ++ rshash_state.lookup_window_index = 0; ++ rshash_state.state = RSHASH_TRYUP; ++ hash_strength_delta = 0; ++ } else { ++ dec_hash_strength(hash_strength_delta); ++ inc_hash_strength_delta(); ++ } ++ break; ++ ++ case RSHASH_TRYUP: ++ if (rshash_state.lookup_window_index++ % 5 == 0) ++ rshash_state.below_count = 0; ++ ++ if (get_current_benefit() < rshash_state.turn_benefit_down) ++ rshash_state.below_count++; ++ else if (get_current_benefit() > rshash_state.turn_benefit_up) { ++ rshash_state.turn_point_up = hash_strength; ++ rshash_state.turn_benefit_up = get_current_benefit(); ++ } ++ ++ if (rshash_state.below_count >= 3 || ++ judge_rshash_direction() == GO_DOWN || ++ hash_strength == HASH_STRENGTH_MAX) { ++ hash_strength = rshash_state.turn_benefit_up > ++ rshash_state.turn_benefit_down ? ++ rshash_state.turn_point_up : ++ rshash_state.turn_point_down; ++ ++ rshash_state.state = RSHASH_PRE_STILL; ++ } else { ++ inc_hash_strength(hash_strength_delta); ++ inc_hash_strength_delta(); ++ } ++ ++ break; ++ ++ case RSHASH_NEW: ++ case RSHASH_PRE_STILL: ++ rshash_state.stable_benefit = get_current_benefit(); ++ rshash_state.state = RSHASH_STILL; ++ hash_strength_delta = 0; ++ break; ++ default: ++ BUG(); ++ } ++ ++ /* rshash_neg = rshash_pos = 0; */ ++ reset_benefit(); ++ ++ if (prev_hash_strength != hash_strength) ++ stable_tree_delta_hash(prev_hash_strength); ++ ++ return prev_hash_strength != hash_strength; ++} ++ ++/** ++ * round_update_ladder() - The main function to do update of all the ++ * adjustments whenever a scan round is finished. ++ */ ++static noinline void round_update_ladder(void) ++{ ++ int i; ++ unsigned long dedup; ++ struct vma_slot *slot, *tmp_slot; ++ ++ for (i = 0; i < SCAN_LADDER_SIZE; i++) { ++ uksm_scan_ladder[i].flags &= ~UKSM_RUNG_ROUND_FINISHED; ++ } ++ ++ list_for_each_entry_safe(slot, tmp_slot, &vma_slot_dedup, dedup_list) { ++ ++ /* slot may be rung_rm_slot() when mm exits */ ++ if (slot->snode) { ++ dedup = cal_dedup_ratio_old(slot); ++ if (dedup && dedup >= uksm_abundant_threshold) ++ vma_rung_up(slot); ++ } ++ ++ slot->pages_bemerged = 0; ++ slot->pages_cowed = 0; ++ ++ list_del_init(&slot->dedup_list); ++ } ++} ++ ++static void uksm_del_vma_slot(struct vma_slot *slot) ++{ ++ int i, j; ++ struct rmap_list_entry *entry; ++ ++ if (slot->snode) { ++ /* ++ * In case it just failed when entering the rung, it's not ++ * necessary. ++ */ ++ rung_rm_slot(slot); ++ } ++ ++ if (!list_empty(&slot->dedup_list)) ++ list_del(&slot->dedup_list); ++ ++ if (!slot->rmap_list_pool || !slot->pool_counts) { ++ /* In case it OOMed in uksm_vma_enter() */ ++ goto out; ++ } ++ ++ for (i = 0; i < slot->pool_size; i++) { ++ void *addr; ++ ++ if (!slot->rmap_list_pool[i]) ++ continue; ++ ++ addr = kmap(slot->rmap_list_pool[i]); ++ for (j = 0; j < PAGE_SIZE / sizeof(*entry); j++) { ++ entry = (struct rmap_list_entry *)addr + j; ++ if (is_addr(entry->addr)) ++ continue; ++ if (!entry->item) ++ continue; ++ ++ remove_rmap_item_from_tree(entry->item); ++ free_rmap_item(entry->item); ++ slot->pool_counts[i]--; ++ } ++ BUG_ON(slot->pool_counts[i]); ++ kunmap(slot->rmap_list_pool[i]); ++ __free_page(slot->rmap_list_pool[i]); ++ } ++ kfree(slot->rmap_list_pool); ++ kfree(slot->pool_counts); ++ ++out: ++ slot->rung = NULL; ++ BUG_ON(uksm_pages_total < slot->pages); ++ if (slot->flags & UKSM_SLOT_IN_UKSM) ++ uksm_pages_total -= slot->pages; ++ ++ if (slot->fully_scanned_round == fully_scanned_round) ++ scanned_virtual_pages -= slot->pages; ++ else ++ scanned_virtual_pages -= slot->pages_scanned; ++ free_vma_slot(slot); ++} ++ ++ ++#define SPIN_LOCK_PERIOD 32 ++static struct vma_slot *cleanup_slots[SPIN_LOCK_PERIOD]; ++static inline void cleanup_vma_slots(void) ++{ ++ struct vma_slot *slot; ++ int i; ++ ++ i = 0; ++ spin_lock(&vma_slot_list_lock); ++ while (!list_empty(&vma_slot_del)) { ++ slot = list_entry(vma_slot_del.next, ++ struct vma_slot, slot_list); ++ list_del(&slot->slot_list); ++ cleanup_slots[i++] = slot; ++ if (i == SPIN_LOCK_PERIOD) { ++ spin_unlock(&vma_slot_list_lock); ++ while (--i >= 0) ++ uksm_del_vma_slot(cleanup_slots[i]); ++ i = 0; ++ spin_lock(&vma_slot_list_lock); ++ } ++ } ++ spin_unlock(&vma_slot_list_lock); ++ ++ while (--i >= 0) ++ uksm_del_vma_slot(cleanup_slots[i]); ++} ++ ++/* ++*expotional moving average formula ++*/ ++static inline unsigned long ema(unsigned long curr, unsigned long last_ema) ++{ ++ /* ++ * For a very high burst, even the ema cannot work well, a false very ++ * high per-page time estimation can result in feedback in very high ++ * overhead of context swith and rung update -- this will then lead ++ * to higher per-paper time, this may not converge. ++ * ++ * Instead, we try to approach this value in a binary manner. ++ */ ++ if (curr > last_ema * 10) ++ return last_ema * 2; ++ ++ return (EMA_ALPHA * curr + (100 - EMA_ALPHA) * last_ema) / 100; ++} ++ ++/* ++ * convert cpu ratio in 1/TIME_RATIO_SCALE configured by user to ++ * nanoseconds based on current uksm_sleep_jiffies. ++ */ ++static inline unsigned long cpu_ratio_to_nsec(unsigned int ratio) ++{ ++ return NSEC_PER_USEC * jiffies_to_usecs(uksm_sleep_jiffies) / ++ (TIME_RATIO_SCALE - ratio) * ratio; ++} ++ ++ ++static inline unsigned long rung_real_ratio(int cpu_time_ratio) ++{ ++ unsigned long ret; ++ ++ BUG_ON(!cpu_time_ratio); ++ ++ if (cpu_time_ratio > 0) ++ ret = cpu_time_ratio; ++ else ++ ret = (unsigned long)(-cpu_time_ratio) * ++ uksm_max_cpu_percentage / 100UL; ++ ++ return ret ? ret : 1; ++} ++ ++static noinline void uksm_calc_scan_pages(void) ++{ ++ struct scan_rung *ladder = uksm_scan_ladder; ++ unsigned long sleep_usecs, nsecs; ++ unsigned long ratio; ++ int i; ++ unsigned long per_page; ++ ++ if (uksm_ema_page_time > 100000 || ++ (((unsigned long) uksm_eval_round & (256UL - 1)) == 0UL)) ++ uksm_ema_page_time = UKSM_PAGE_TIME_DEFAULT; ++ ++ per_page = uksm_ema_page_time; ++ BUG_ON(!per_page); ++ ++ /* ++ * For every 8 eval round, we try to probe a uksm_sleep_jiffies value ++ * based on saved user input. ++ */ ++ if (((unsigned long) uksm_eval_round & (8UL - 1)) == 0UL) ++ uksm_sleep_jiffies = uksm_sleep_saved; ++ ++ /* We require a rung scan at least 1 page in a period. */ ++ nsecs = per_page; ++ ratio = rung_real_ratio(ladder[0].cpu_ratio); ++ if (cpu_ratio_to_nsec(ratio) < nsecs) { ++ sleep_usecs = nsecs * (TIME_RATIO_SCALE - ratio) / ratio ++ / NSEC_PER_USEC; ++ uksm_sleep_jiffies = usecs_to_jiffies(sleep_usecs) + 1; ++ } ++ ++ for (i = 0; i < SCAN_LADDER_SIZE; i++) { ++ ratio = rung_real_ratio(ladder[i].cpu_ratio); ++ ladder[i].pages_to_scan = cpu_ratio_to_nsec(ratio) / ++ per_page; ++ BUG_ON(!ladder[i].pages_to_scan); ++ uksm_calc_rung_step(&ladder[i], per_page, ratio); ++ } ++} ++ ++/* ++ * From the scan time of this round (ns) to next expected min sleep time ++ * (ms), be careful of the possible overflows. ratio is taken from ++ * rung_real_ratio() ++ */ ++static inline ++unsigned int scan_time_to_sleep(unsigned long long scan_time, unsigned long ratio) ++{ ++ scan_time >>= 20; /* to msec level now */ ++ BUG_ON(scan_time > (ULONG_MAX / TIME_RATIO_SCALE)); ++ ++ return (unsigned int) ((unsigned long) scan_time * ++ (TIME_RATIO_SCALE - ratio) / ratio); ++} ++ ++#define __round_mask(x, y) ((__typeof__(x))((y)-1)) ++#define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1) ++ ++static inline unsigned long vma_pool_size(struct vma_slot *slot) ++{ ++ return round_up(sizeof(struct rmap_list_entry) * slot->pages, ++ PAGE_SIZE) >> PAGE_SHIFT; ++} ++ ++static void uksm_vma_enter(struct vma_slot **slots, unsigned long num) ++{ ++ struct scan_rung *rung; ++ unsigned long pool_size, i; ++ struct vma_slot *slot; ++ int failed; ++ ++ rung = &uksm_scan_ladder[0]; ++ ++ failed = 0; ++ for (i = 0; i < num; i++) { ++ slot = slots[i]; ++ ++ pool_size = vma_pool_size(slot); ++ slot->rmap_list_pool = kzalloc(sizeof(struct page *) * ++ pool_size, GFP_KERNEL); ++ if (!slot->rmap_list_pool) ++ break; ++ ++ slot->pool_counts = kzalloc(sizeof(unsigned int) * pool_size, ++ GFP_KERNEL); ++ if (!slot->pool_counts) { ++ kfree(slot->rmap_list_pool); ++ break; ++ } ++ ++ slot->pool_size = pool_size; ++ BUG_ON(CAN_OVERFLOW_U64(uksm_pages_total, slot->pages)); ++ slot->flags |= UKSM_SLOT_IN_UKSM; ++ uksm_pages_total += slot->pages; ++ } ++ ++ if (i) ++ rung_add_new_slots(rung, slots, i); ++ ++ return; ++} ++ ++static struct vma_slot *batch_slots[SLOT_TREE_NODE_STORE_SIZE]; ++ ++static void uksm_enter_all_slots(void) ++{ ++ struct vma_slot *slot; ++ unsigned long index; ++ struct list_head empty_vma_list; ++ int i; ++ ++ i = 0; ++ index = 0; ++ INIT_LIST_HEAD(&empty_vma_list); ++ ++ spin_lock(&vma_slot_list_lock); ++ while (!list_empty(&vma_slot_new)) { ++ slot = list_entry(vma_slot_new.next, ++ struct vma_slot, slot_list); ++ ++ if (!slot->vma->anon_vma) { ++ list_move(&slot->slot_list, &empty_vma_list); ++ } else if (vma_can_enter(slot->vma)) { ++ batch_slots[index++] = slot; ++ list_del_init(&slot->slot_list); ++ } else { ++ list_move(&slot->slot_list, &vma_slot_noadd); ++ } ++ ++ if (++i == SPIN_LOCK_PERIOD || ++ (index && !(index % SLOT_TREE_NODE_STORE_SIZE))) { ++ spin_unlock(&vma_slot_list_lock); ++ ++ if (index && !(index % SLOT_TREE_NODE_STORE_SIZE)) { ++ uksm_vma_enter(batch_slots, index); ++ index = 0; ++ } ++ i = 0; ++ cond_resched(); ++ spin_lock(&vma_slot_list_lock); ++ } ++ } ++ ++ list_splice(&empty_vma_list, &vma_slot_new); ++ ++ spin_unlock(&vma_slot_list_lock); ++ ++ if (index) ++ uksm_vma_enter(batch_slots, index); ++ ++} ++ ++static inline int rung_round_finished(struct scan_rung *rung) ++{ ++ return rung->flags & UKSM_RUNG_ROUND_FINISHED; ++} ++ ++static inline void judge_slot(struct vma_slot *slot) ++{ ++ struct scan_rung *rung = slot->rung; ++ unsigned long dedup; ++ int deleted; ++ ++ dedup = cal_dedup_ratio(slot); ++ if (vma_fully_scanned(slot) && uksm_thrash_threshold) ++ deleted = vma_rung_enter(slot, &uksm_scan_ladder[0]); ++ else if (dedup && dedup >= uksm_abundant_threshold) ++ deleted = vma_rung_up(slot); ++ else ++ deleted = vma_rung_down(slot); ++ ++ slot->pages_merged = 0; ++ slot->pages_cowed = 0; ++ ++ if (vma_fully_scanned(slot)) ++ slot->pages_scanned = 0; ++ ++ slot->last_scanned = slot->pages_scanned; ++ ++ /* If its deleted in above, then rung was already advanced. */ ++ if (!deleted) ++ advance_current_scan(rung); ++} ++ ++ ++static inline int hash_round_finished(void) ++{ ++ if (scanned_virtual_pages > (uksm_pages_total >> 2)) { ++ scanned_virtual_pages = 0; ++ if (uksm_pages_scanned) ++ fully_scanned_round++; ++ ++ return 1; ++ } else { ++ return 0; ++ } ++} ++ ++#define UKSM_MMSEM_BATCH 5 ++#define BUSY_RETRY 100 ++ ++/** ++ * uksm_do_scan() - the main worker function. ++ */ ++static noinline void uksm_do_scan(void) ++{ ++ struct vma_slot *slot, *iter; ++ struct mm_struct *busy_mm; ++ unsigned char round_finished, all_rungs_emtpy; ++ int i, err, mmsem_batch; ++ unsigned long pcost; ++ long long delta_exec; ++ unsigned long vpages, max_cpu_ratio; ++ unsigned long long start_time, end_time, scan_time; ++ unsigned int expected_jiffies; ++ ++ might_sleep(); ++ ++ vpages = 0; ++ ++ start_time = task_sched_runtime(current); ++ max_cpu_ratio = 0; ++ mmsem_batch = 0; ++ ++ for (i = 0; i < SCAN_LADDER_SIZE;) { ++ struct scan_rung *rung = &uksm_scan_ladder[i]; ++ unsigned long ratio; ++ int busy_retry; ++ ++ if (!rung->pages_to_scan) { ++ i++; ++ continue; ++ } ++ ++ if (!rung->vma_root.num) { ++ rung->pages_to_scan = 0; ++ i++; ++ continue; ++ } ++ ++ ratio = rung_real_ratio(rung->cpu_ratio); ++ if (ratio > max_cpu_ratio) ++ max_cpu_ratio = ratio; ++ ++ busy_retry = BUSY_RETRY; ++ /* ++ * Do not consider rung_round_finished() here, just used up the ++ * rung->pages_to_scan quota. ++ */ ++ while (rung->pages_to_scan && rung->vma_root.num && ++ likely(!freezing(current))) { ++ int reset = 0; ++ ++ slot = rung->current_scan; ++ ++ BUG_ON(vma_fully_scanned(slot)); ++ ++ if (mmsem_batch) { ++ err = 0; ++ } else { ++ err = try_down_read_slot_mmap_sem(slot); ++ } ++ ++ if (err == -ENOENT) { ++rm_slot: ++ rung_rm_slot(slot); ++ continue; ++ } ++ ++ busy_mm = slot->mm; ++ ++ if (err == -EBUSY) { ++ /* skip other vmas on the same mm */ ++ do { ++ reset = advance_current_scan(rung); ++ iter = rung->current_scan; ++ busy_retry--; ++ if (iter->vma->vm_mm != busy_mm || ++ !busy_retry || reset) ++ break; ++ } while (1); ++ ++ if (iter->vma->vm_mm != busy_mm) { ++ continue; ++ } else { ++ /* scan round finsished */ ++ break; ++ } ++ } ++ ++ BUG_ON(!vma_can_enter(slot->vma)); ++ if (uksm_test_exit(slot->vma->vm_mm)) { ++ mmsem_batch = 0; ++ up_read(&slot->vma->vm_mm->mmap_sem); ++ goto rm_slot; ++ } ++ ++ if (mmsem_batch) ++ mmsem_batch--; ++ else ++ mmsem_batch = UKSM_MMSEM_BATCH; ++ ++ /* Ok, we have take the mmap_sem, ready to scan */ ++ scan_vma_one_page(slot); ++ rung->pages_to_scan--; ++ vpages++; ++ ++ if (rung->current_offset + rung->step > slot->pages - 1 ++ || vma_fully_scanned(slot)) { ++ up_read(&slot->vma->vm_mm->mmap_sem); ++ judge_slot(slot); ++ mmsem_batch = 0; ++ } else { ++ rung->current_offset += rung->step; ++ if (!mmsem_batch) ++ up_read(&slot->vma->vm_mm->mmap_sem); ++ } ++ ++ busy_retry = BUSY_RETRY; ++ cond_resched(); ++ } ++ ++ if (mmsem_batch) { ++ up_read(&slot->vma->vm_mm->mmap_sem); ++ mmsem_batch = 0; ++ } ++ ++ if (freezing(current)) ++ break; ++ ++ cond_resched(); ++ } ++ end_time = task_sched_runtime(current); ++ delta_exec = end_time - start_time; ++ ++ if (freezing(current)) ++ return; ++ ++ cleanup_vma_slots(); ++ uksm_enter_all_slots(); ++ ++ round_finished = 1; ++ all_rungs_emtpy = 1; ++ for (i = 0; i < SCAN_LADDER_SIZE; i++) { ++ struct scan_rung *rung = &uksm_scan_ladder[i]; ++ ++ if (rung->vma_root.num) { ++ all_rungs_emtpy = 0; ++ if (!rung_round_finished(rung)) ++ round_finished = 0; ++ } ++ } ++ ++ if (all_rungs_emtpy) ++ round_finished = 0; ++ ++ if (round_finished) { ++ round_update_ladder(); ++ uksm_eval_round++; ++ ++ if (hash_round_finished() && rshash_adjust()) { ++ /* Reset the unstable root iff hash strength changed */ ++ uksm_hash_round++; ++ root_unstable_tree = RB_ROOT; ++ free_all_tree_nodes(&unstable_tree_node_list); ++ } ++ ++ /* ++ * A number of pages can hang around indefinitely on per-cpu ++ * pagevecs, raised page count preventing write_protect_page ++ * from merging them. Though it doesn't really matter much, ++ * it is puzzling to see some stuck in pages_volatile until ++ * other activity jostles them out, and they also prevented ++ * LTP's KSM test from succeeding deterministically; so drain ++ * them here (here rather than on entry to uksm_do_scan(), ++ * so we don't IPI too often when pages_to_scan is set low). ++ */ ++ lru_add_drain_all(); ++ } ++ ++ ++ if (vpages && delta_exec > 0) { ++ pcost = (unsigned long) delta_exec / vpages; ++ if (likely(uksm_ema_page_time)) ++ uksm_ema_page_time = ema(pcost, uksm_ema_page_time); ++ else ++ uksm_ema_page_time = pcost; ++ } ++ ++ uksm_calc_scan_pages(); ++ uksm_sleep_real = uksm_sleep_jiffies; ++ /* in case of radical cpu bursts, apply the upper bound */ ++ end_time = task_sched_runtime(current); ++ if (max_cpu_ratio && end_time > start_time) { ++ scan_time = end_time - start_time; ++ expected_jiffies = msecs_to_jiffies( ++ scan_time_to_sleep(scan_time, max_cpu_ratio)); ++ ++ if (expected_jiffies > uksm_sleep_real) ++ uksm_sleep_real = expected_jiffies; ++ ++ /* We have a 1 second up bound for responsiveness. */ ++ if (jiffies_to_msecs(uksm_sleep_real) > MSEC_PER_SEC) ++ uksm_sleep_real = msecs_to_jiffies(1000); ++ } ++ ++ return; ++} ++ ++static int ksmd_should_run(void) ++{ ++ return uksm_run & UKSM_RUN_MERGE; ++} ++ ++static int uksm_scan_thread(void *nothing) ++{ ++ set_freezable(); ++ set_user_nice(current, 5); ++ ++ while (!kthread_should_stop()) { ++ mutex_lock(&uksm_thread_mutex); ++ if (ksmd_should_run()) { ++ uksm_do_scan(); ++ } ++ mutex_unlock(&uksm_thread_mutex); ++ ++ try_to_freeze(); ++ ++ if (ksmd_should_run()) { ++ schedule_timeout_interruptible(uksm_sleep_real); ++ uksm_sleep_times++; ++ } else { ++ wait_event_freezable(uksm_thread_wait, ++ ksmd_should_run() || kthread_should_stop()); ++ } ++ } ++ return 0; ++} ++ ++int page_referenced_ksm(struct page *page, struct mem_cgroup *memcg, ++ unsigned long *vm_flags) ++{ ++ struct stable_node *stable_node; ++ struct node_vma *node_vma; ++ struct rmap_item *rmap_item; ++ unsigned int mapcount = page_mapcount(page); ++ int referenced = 0; ++ int search_new_forks = 0; ++ unsigned long address; ++ ++ VM_BUG_ON(!PageKsm(page)); ++ VM_BUG_ON(!PageLocked(page)); ++ ++ stable_node = page_stable_node(page); ++ if (!stable_node) ++ return 0; ++ ++ ++again: ++ hlist_for_each_entry(node_vma, &stable_node->hlist, hlist) { ++ hlist_for_each_entry(rmap_item, &node_vma->rmap_hlist, hlist) { ++ struct anon_vma *anon_vma = rmap_item->anon_vma; ++ struct anon_vma_chain *vmac; ++ struct vm_area_struct *vma; ++ ++ anon_vma_lock_read(anon_vma); ++ anon_vma_interval_tree_foreach(vmac, &anon_vma->rb_root, ++ 0, ULONG_MAX) { ++ ++ vma = vmac->vma; ++ address = get_rmap_addr(rmap_item); ++ ++ if (address < vma->vm_start || ++ address >= vma->vm_end) ++ continue; ++ /* ++ * Initially we examine only the vma which ++ * covers this rmap_item; but later, if there ++ * is still work to do, we examine covering ++ * vmas in other mms: in case they were forked ++ * from the original since ksmd passed. ++ */ ++ if ((rmap_item->slot->vma == vma) == ++ search_new_forks) ++ continue; ++ ++ if (memcg && ++ !mm_match_cgroup(vma->vm_mm, memcg)) ++ continue; ++ ++ referenced += ++ page_referenced_one(page, vma, ++ address, &mapcount, vm_flags); ++ if (!search_new_forks || !mapcount) ++ break; ++ } ++ ++ anon_vma_unlock_read(anon_vma); ++ if (!mapcount) ++ goto out; ++ } ++ } ++ if (!search_new_forks++) ++ goto again; ++out: ++ return referenced; ++} ++ ++int try_to_unmap_ksm(struct page *page, enum ttu_flags flags) ++{ ++ struct stable_node *stable_node; ++ struct node_vma *node_vma; ++ struct rmap_item *rmap_item; ++ int ret = SWAP_AGAIN; ++ int search_new_forks = 0; ++ unsigned long address; ++ ++ VM_BUG_ON(!PageKsm(page)); ++ VM_BUG_ON(!PageLocked(page)); ++ ++ stable_node = page_stable_node(page); ++ if (!stable_node) ++ return SWAP_FAIL; ++again: ++ hlist_for_each_entry(node_vma, &stable_node->hlist, hlist) { ++ hlist_for_each_entry(rmap_item, &node_vma->rmap_hlist, hlist) { ++ struct anon_vma *anon_vma = rmap_item->anon_vma; ++ struct anon_vma_chain *vmac; ++ struct vm_area_struct *vma; ++ ++ anon_vma_lock_read(anon_vma); ++ anon_vma_interval_tree_foreach(vmac, &anon_vma->rb_root, ++ 0, ULONG_MAX) { ++ vma = vmac->vma; ++ address = get_rmap_addr(rmap_item); ++ ++ if (address < vma->vm_start || ++ address >= vma->vm_end) ++ continue; ++ /* ++ * Initially we examine only the vma which ++ * covers this rmap_item; but later, if there ++ * is still work to do, we examine covering ++ * vmas in other mms: in case they were forked ++ * from the original since ksmd passed. ++ */ ++ if ((rmap_item->slot->vma == vma) == ++ search_new_forks) ++ continue; ++ ++ ret = try_to_unmap_one(page, vma, ++ address, flags); ++ if (ret != SWAP_AGAIN || !page_mapped(page)) { ++ anon_vma_unlock_read(anon_vma); ++ goto out; ++ } ++ } ++ anon_vma_unlock_read(anon_vma); ++ } ++ } ++ if (!search_new_forks++) ++ goto again; ++out: ++ return ret; ++} ++ ++#ifdef CONFIG_MIGRATION ++int rmap_walk_ksm(struct page *page, int (*rmap_one)(struct page *, ++ struct vm_area_struct *, unsigned long, void *), void *arg) ++{ ++ struct stable_node *stable_node; ++ struct node_vma *node_vma; ++ struct rmap_item *rmap_item; ++ int ret = SWAP_AGAIN; ++ int search_new_forks = 0; ++ unsigned long address; ++ ++ VM_BUG_ON(!PageKsm(page)); ++ VM_BUG_ON(!PageLocked(page)); ++ ++ stable_node = page_stable_node(page); ++ if (!stable_node) ++ return ret; ++again: ++ hlist_for_each_entry(node_vma, &stable_node->hlist, hlist) { ++ hlist_for_each_entry(rmap_item, &node_vma->rmap_hlist, hlist) { ++ struct anon_vma *anon_vma = rmap_item->anon_vma; ++ struct anon_vma_chain *vmac; ++ struct vm_area_struct *vma; ++ ++ anon_vma_lock_read(anon_vma); ++ anon_vma_interval_tree_foreach(vmac, &anon_vma->rb_root, ++ 0, ULONG_MAX) { ++ vma = vmac->vma; ++ address = get_rmap_addr(rmap_item); ++ ++ if (address < vma->vm_start || ++ address >= vma->vm_end) ++ continue; ++ ++ if ((rmap_item->slot->vma == vma) == ++ search_new_forks) ++ continue; ++ ++ ret = rmap_one(page, vma, address, arg); ++ if (ret != SWAP_AGAIN) { ++ anon_vma_unlock_read(anon_vma); ++ goto out; ++ } ++ } ++ anon_vma_unlock_read(anon_vma); ++ } ++ } ++ if (!search_new_forks++) ++ goto again; ++out: ++ return ret; ++} ++ ++/* Common ksm interface but may be specific to uksm */ ++void ksm_migrate_page(struct page *newpage, struct page *oldpage) ++{ ++ struct stable_node *stable_node; ++ ++ VM_BUG_ON(!PageLocked(oldpage)); ++ VM_BUG_ON(!PageLocked(newpage)); ++ VM_BUG_ON(newpage->mapping != oldpage->mapping); ++ ++ stable_node = page_stable_node(newpage); ++ if (stable_node) { ++ VM_BUG_ON(stable_node->kpfn != page_to_pfn(oldpage)); ++ stable_node->kpfn = page_to_pfn(newpage); ++ } ++} ++#endif /* CONFIG_MIGRATION */ ++ ++#ifdef CONFIG_MEMORY_HOTREMOVE ++static struct stable_node *uksm_check_stable_tree(unsigned long start_pfn, ++ unsigned long end_pfn) ++{ ++ struct rb_node *node; ++ ++ for (node = rb_first(root_stable_treep); node; node = rb_next(node)) { ++ struct stable_node *stable_node; ++ ++ stable_node = rb_entry(node, struct stable_node, node); ++ if (stable_node->kpfn >= start_pfn && ++ stable_node->kpfn < end_pfn) ++ return stable_node; ++ } ++ return NULL; ++} ++ ++static int uksm_memory_callback(struct notifier_block *self, ++ unsigned long action, void *arg) ++{ ++ struct memory_notify *mn = arg; ++ struct stable_node *stable_node; ++ ++ switch (action) { ++ case MEM_GOING_OFFLINE: ++ /* ++ * Keep it very simple for now: just lock out ksmd and ++ * MADV_UNMERGEABLE while any memory is going offline. ++ * mutex_lock_nested() is necessary because lockdep was alarmed ++ * that here we take uksm_thread_mutex inside notifier chain ++ * mutex, and later take notifier chain mutex inside ++ * uksm_thread_mutex to unlock it. But that's safe because both ++ * are inside mem_hotplug_mutex. ++ */ ++ mutex_lock_nested(&uksm_thread_mutex, SINGLE_DEPTH_NESTING); ++ break; ++ ++ case MEM_OFFLINE: ++ /* ++ * Most of the work is done by page migration; but there might ++ * be a few stable_nodes left over, still pointing to struct ++ * pages which have been offlined: prune those from the tree. ++ */ ++ while ((stable_node = uksm_check_stable_tree(mn->start_pfn, ++ mn->start_pfn + mn->nr_pages)) != NULL) ++ remove_node_from_stable_tree(stable_node, 1, 1); ++ /* fallthrough */ ++ ++ case MEM_CANCEL_OFFLINE: ++ mutex_unlock(&uksm_thread_mutex); ++ break; ++ } ++ return NOTIFY_OK; ++} ++#endif /* CONFIG_MEMORY_HOTREMOVE */ ++ ++#ifdef CONFIG_SYSFS ++/* ++ * This all compiles without CONFIG_SYSFS, but is a waste of space. ++ */ ++ ++#define UKSM_ATTR_RO(_name) \ ++ static struct kobj_attribute _name##_attr = __ATTR_RO(_name) ++#define UKSM_ATTR(_name) \ ++ static struct kobj_attribute _name##_attr = \ ++ __ATTR(_name, 0644, _name##_show, _name##_store) ++ ++static ssize_t max_cpu_percentage_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ return sprintf(buf, "%u\n", uksm_max_cpu_percentage); ++} ++ ++static ssize_t max_cpu_percentage_store(struct kobject *kobj, ++ struct kobj_attribute *attr, ++ const char *buf, size_t count) ++{ ++ unsigned long max_cpu_percentage; ++ int err; ++ ++ err = strict_strtoul(buf, 10, &max_cpu_percentage); ++ if (err || max_cpu_percentage > 100) ++ return -EINVAL; ++ ++ if (max_cpu_percentage == 100) ++ max_cpu_percentage = 99; ++ else if (max_cpu_percentage < 10) ++ max_cpu_percentage = 10; ++ ++ uksm_max_cpu_percentage = max_cpu_percentage; ++ ++ return count; ++} ++UKSM_ATTR(max_cpu_percentage); ++ ++static ssize_t sleep_millisecs_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ return sprintf(buf, "%u\n", jiffies_to_msecs(uksm_sleep_jiffies)); ++} ++ ++static ssize_t sleep_millisecs_store(struct kobject *kobj, ++ struct kobj_attribute *attr, ++ const char *buf, size_t count) ++{ ++ unsigned long msecs; ++ int err; ++ ++ err = strict_strtoul(buf, 10, &msecs); ++ if (err || msecs > MSEC_PER_SEC) ++ return -EINVAL; ++ ++ uksm_sleep_jiffies = msecs_to_jiffies(msecs); ++ uksm_sleep_saved = uksm_sleep_jiffies; ++ ++ return count; ++} ++UKSM_ATTR(sleep_millisecs); ++ ++ ++static ssize_t cpu_governor_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ int n = sizeof(uksm_cpu_governor_str) / sizeof(char *); ++ int i; ++ ++ buf[0] = '\0'; ++ for (i = 0; i < n ; i++) { ++ if (uksm_cpu_governor == i) ++ strcat(buf, "["); ++ ++ strcat(buf, uksm_cpu_governor_str[i]); ++ ++ if (uksm_cpu_governor == i) ++ strcat(buf, "]"); ++ ++ strcat(buf, " "); ++ } ++ strcat(buf, "\n"); ++ ++ return strlen(buf); ++} ++ ++static inline void init_performance_values(void) ++{ ++ int i; ++ struct scan_rung *rung; ++ struct uksm_cpu_preset_s *preset = uksm_cpu_preset + uksm_cpu_governor; ++ ++ ++ for (i = 0; i < SCAN_LADDER_SIZE; i++) { ++ rung = uksm_scan_ladder + i; ++ rung->cpu_ratio = preset->cpu_ratio[i]; ++ rung->cover_msecs = preset->cover_msecs[i]; ++ } ++ ++ uksm_max_cpu_percentage = preset->max_cpu; ++} ++ ++static ssize_t cpu_governor_store(struct kobject *kobj, ++ struct kobj_attribute *attr, ++ const char *buf, size_t count) ++{ ++ int n = sizeof(uksm_cpu_governor_str) / sizeof(char *); ++ ++ for (n--; n >=0 ; n--) { ++ if (!strncmp(buf, uksm_cpu_governor_str[n], ++ strlen(uksm_cpu_governor_str[n]))) ++ break; ++ } ++ ++ if (n < 0) ++ return -EINVAL; ++ else ++ uksm_cpu_governor = n; ++ ++ init_performance_values(); ++ ++ return count; ++} ++UKSM_ATTR(cpu_governor); ++ ++static ssize_t run_show(struct kobject *kobj, struct kobj_attribute *attr, ++ char *buf) ++{ ++ return sprintf(buf, "%u\n", uksm_run); ++} ++ ++static ssize_t run_store(struct kobject *kobj, struct kobj_attribute *attr, ++ const char *buf, size_t count) ++{ ++ int err; ++ unsigned long flags; ++ ++ err = strict_strtoul(buf, 10, &flags); ++ if (err || flags > UINT_MAX) ++ return -EINVAL; ++ if (flags > UKSM_RUN_MERGE) ++ return -EINVAL; ++ ++ mutex_lock(&uksm_thread_mutex); ++ if (uksm_run != flags) { ++ uksm_run = flags; ++ } ++ mutex_unlock(&uksm_thread_mutex); ++ ++ if (flags & UKSM_RUN_MERGE) ++ wake_up_interruptible(&uksm_thread_wait); ++ ++ return count; ++} ++UKSM_ATTR(run); ++ ++static ssize_t abundant_threshold_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ return sprintf(buf, "%u\n", uksm_abundant_threshold); ++} ++ ++static ssize_t abundant_threshold_store(struct kobject *kobj, ++ struct kobj_attribute *attr, ++ const char *buf, size_t count) ++{ ++ int err; ++ unsigned long flags; ++ ++ err = strict_strtoul(buf, 10, &flags); ++ if (err || flags > 99) ++ return -EINVAL; ++ ++ uksm_abundant_threshold = flags; ++ ++ return count; ++} ++UKSM_ATTR(abundant_threshold); ++ ++static ssize_t thrash_threshold_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ return sprintf(buf, "%u\n", uksm_thrash_threshold); ++} ++ ++static ssize_t thrash_threshold_store(struct kobject *kobj, ++ struct kobj_attribute *attr, ++ const char *buf, size_t count) ++{ ++ int err; ++ unsigned long flags; ++ ++ err = strict_strtoul(buf, 10, &flags); ++ if (err || flags > 99) ++ return -EINVAL; ++ ++ uksm_thrash_threshold = flags; ++ ++ return count; ++} ++UKSM_ATTR(thrash_threshold); ++ ++static ssize_t cpu_ratios_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ int i, size; ++ struct scan_rung *rung; ++ char *p = buf; ++ ++ for (i = 0; i < SCAN_LADDER_SIZE; i++) { ++ rung = &uksm_scan_ladder[i]; ++ ++ if (rung->cpu_ratio > 0) ++ size = sprintf(p, "%d ", rung->cpu_ratio); ++ else ++ size = sprintf(p, "MAX/%d ", ++ TIME_RATIO_SCALE / -rung->cpu_ratio); ++ ++ p += size; ++ } ++ ++ *p++ = '\n'; ++ *p = '\0'; ++ ++ return p - buf; ++} ++ ++static ssize_t cpu_ratios_store(struct kobject *kobj, ++ struct kobj_attribute *attr, ++ const char *buf, size_t count) ++{ ++ int i, cpuratios[SCAN_LADDER_SIZE], err; ++ unsigned long value; ++ struct scan_rung *rung; ++ char *p, *end = NULL; ++ ++ p = kzalloc(count, GFP_KERNEL); ++ if (!p) ++ return -ENOMEM; ++ ++ memcpy(p, buf, count); ++ ++ for (i = 0; i < SCAN_LADDER_SIZE; i++) { ++ if (i != SCAN_LADDER_SIZE -1) { ++ end = strchr(p, ' '); ++ if (!end) ++ return -EINVAL; ++ ++ *end = '\0'; ++ } ++ ++ if (strstr(p, "MAX/")) { ++ p = strchr(p, '/') + 1; ++ err = strict_strtoul(p, 10, &value); ++ if (err || value > TIME_RATIO_SCALE || !value) ++ return -EINVAL; ++ ++ cpuratios[i] = - (int) (TIME_RATIO_SCALE / value); ++ } else { ++ err = strict_strtoul(p, 10, &value); ++ if (err || value > TIME_RATIO_SCALE || !value) ++ return -EINVAL; ++ ++ cpuratios[i] = value; ++ } ++ ++ p = end + 1; ++ } ++ ++ for (i = 0; i < SCAN_LADDER_SIZE; i++) { ++ rung = &uksm_scan_ladder[i]; ++ ++ rung->cpu_ratio = cpuratios[i]; ++ } ++ ++ return count; ++} ++UKSM_ATTR(cpu_ratios); ++ ++static ssize_t eval_intervals_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ int i, size; ++ struct scan_rung *rung; ++ char *p = buf; ++ ++ for (i = 0; i < SCAN_LADDER_SIZE; i++) { ++ rung = &uksm_scan_ladder[i]; ++ size = sprintf(p, "%u ", rung->cover_msecs); ++ p += size; ++ } ++ ++ *p++ = '\n'; ++ *p = '\0'; ++ ++ return p - buf; ++} ++ ++static ssize_t eval_intervals_store(struct kobject *kobj, ++ struct kobj_attribute *attr, ++ const char *buf, size_t count) ++{ ++ int i, err; ++ unsigned long values[SCAN_LADDER_SIZE]; ++ struct scan_rung *rung; ++ char *p, *end = NULL; ++ ++ p = kzalloc(count, GFP_KERNEL); ++ if (!p) ++ return -ENOMEM; ++ ++ memcpy(p, buf, count); ++ ++ for (i = 0; i < SCAN_LADDER_SIZE; i++) { ++ if (i != SCAN_LADDER_SIZE -1) { ++ end = strchr(p, ' '); ++ if (!end) ++ return -EINVAL; ++ ++ *end = '\0'; ++ } ++ ++ err = strict_strtoul(p, 10, &values[i]); ++ if (err) ++ return -EINVAL; ++ ++ p = end + 1; ++ } ++ ++ for (i = 0; i < SCAN_LADDER_SIZE; i++) { ++ rung = &uksm_scan_ladder[i]; ++ ++ rung->cover_msecs = values[i]; ++ } ++ ++ return count; ++} ++UKSM_ATTR(eval_intervals); ++ ++static ssize_t ema_per_page_time_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ return sprintf(buf, "%lu\n", uksm_ema_page_time); ++} ++UKSM_ATTR_RO(ema_per_page_time); ++ ++static ssize_t pages_shared_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ return sprintf(buf, "%lu\n", uksm_pages_shared); ++} ++UKSM_ATTR_RO(pages_shared); ++ ++static ssize_t pages_sharing_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ return sprintf(buf, "%lu\n", uksm_pages_sharing); ++} ++UKSM_ATTR_RO(pages_sharing); ++ ++static ssize_t pages_unshared_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ return sprintf(buf, "%lu\n", uksm_pages_unshared); ++} ++UKSM_ATTR_RO(pages_unshared); ++ ++static ssize_t full_scans_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ return sprintf(buf, "%llu\n", fully_scanned_round); ++} ++UKSM_ATTR_RO(full_scans); ++ ++static ssize_t pages_scanned_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ unsigned long base = 0; ++ u64 delta, ret; ++ ++ if (pages_scanned_stored) { ++ base = pages_scanned_base; ++ ret = pages_scanned_stored; ++ delta = uksm_pages_scanned >> base; ++ if (CAN_OVERFLOW_U64(ret, delta)) { ++ ret >>= 1; ++ delta >>= 1; ++ base++; ++ ret += delta; ++ } ++ } else { ++ ret = uksm_pages_scanned; ++ } ++ ++ while (ret > ULONG_MAX) { ++ ret >>= 1; ++ base++; ++ } ++ ++ if (base) ++ return sprintf(buf, "%lu * 2^%lu\n", (unsigned long)ret, base); ++ else ++ return sprintf(buf, "%lu\n", (unsigned long)ret); ++} ++UKSM_ATTR_RO(pages_scanned); ++ ++static ssize_t hash_strength_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ return sprintf(buf, "%lu\n", hash_strength); ++} ++UKSM_ATTR_RO(hash_strength); ++ ++static ssize_t sleep_times_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ return sprintf(buf, "%llu\n", uksm_sleep_times); ++} ++UKSM_ATTR_RO(sleep_times); ++ ++ ++static struct attribute *uksm_attrs[] = { ++ &max_cpu_percentage_attr.attr, ++ &sleep_millisecs_attr.attr, ++ &cpu_governor_attr.attr, ++ &run_attr.attr, ++ &ema_per_page_time_attr.attr, ++ &pages_shared_attr.attr, ++ &pages_sharing_attr.attr, ++ &pages_unshared_attr.attr, ++ &full_scans_attr.attr, ++ &pages_scanned_attr.attr, ++ &hash_strength_attr.attr, ++ &sleep_times_attr.attr, ++ &thrash_threshold_attr.attr, ++ &abundant_threshold_attr.attr, ++ &cpu_ratios_attr.attr, ++ &eval_intervals_attr.attr, ++ NULL, ++}; ++ ++static struct attribute_group uksm_attr_group = { ++ .attrs = uksm_attrs, ++ .name = "uksm", ++}; ++#endif /* CONFIG_SYSFS */ ++ ++static inline void init_scan_ladder(void) ++{ ++ int i; ++ struct scan_rung *rung; ++ ++ for (i = 0; i < SCAN_LADDER_SIZE; i++) { ++ rung = uksm_scan_ladder + i; ++ slot_tree_init_root(&rung->vma_root); ++ } ++ ++ init_performance_values(); ++ uksm_calc_scan_pages(); ++} ++ ++static inline int cal_positive_negative_costs(void) ++{ ++ struct page *p1, *p2; ++ unsigned char *addr1, *addr2; ++ unsigned long i, time_start, hash_cost; ++ unsigned long loopnum = 0; ++ ++ /*IMPORTANT: volatile is needed to prevent over-optimization by gcc. */ ++ volatile u32 hash; ++ volatile int ret; ++ ++ p1 = alloc_page(GFP_KERNEL); ++ if (!p1) ++ return -ENOMEM; ++ ++ p2 = alloc_page(GFP_KERNEL); ++ if (!p2) ++ return -ENOMEM; ++ ++ addr1 = kmap_atomic(p1); ++ addr2 = kmap_atomic(p2); ++ memset(addr1, prandom_u32(), PAGE_SIZE); ++ memcpy(addr2, addr1, PAGE_SIZE); ++ ++ /* make sure that the two pages differ in last byte */ ++ addr2[PAGE_SIZE-1] = ~addr2[PAGE_SIZE-1]; ++ kunmap_atomic(addr2); ++ kunmap_atomic(addr1); ++ ++ time_start = jiffies; ++ while (jiffies - time_start < 100) { ++ for (i = 0; i < 100; i++) ++ hash = page_hash(p1, HASH_STRENGTH_FULL, 0); ++ loopnum += 100; ++ } ++ hash_cost = (jiffies - time_start); ++ ++ time_start = jiffies; ++ for (i = 0; i < loopnum; i++) ++ ret = pages_identical(p1, p2); ++ memcmp_cost = HASH_STRENGTH_FULL * (jiffies - time_start); ++ memcmp_cost /= hash_cost; ++ printk(KERN_INFO "UKSM: relative memcmp_cost = %lu " ++ "hash=%u cmp_ret=%d.\n", ++ memcmp_cost, hash, ret); ++ ++ __free_page(p1); ++ __free_page(p2); ++ return 0; ++} ++ ++static int init_zeropage_hash_table(void) ++{ ++ struct page *page; ++ char *addr; ++ int i; ++ ++ page = alloc_page(GFP_KERNEL); ++ if (!page) ++ return -ENOMEM; ++ ++ addr = kmap_atomic(page); ++ memset(addr, 0, PAGE_SIZE); ++ kunmap_atomic(addr); ++ ++ zero_hash_table = kmalloc(HASH_STRENGTH_MAX * sizeof(u32), ++ GFP_KERNEL); ++ if (!zero_hash_table) ++ return -ENOMEM; ++ ++ for (i = 0; i < HASH_STRENGTH_MAX; i++) ++ zero_hash_table[i] = page_hash(page, i, 0); ++ ++ __free_page(page); ++ ++ return 0; ++} ++ ++static inline int init_random_sampling(void) ++{ ++ unsigned long i; ++ random_nums = kmalloc(PAGE_SIZE, GFP_KERNEL); ++ if (!random_nums) ++ return -ENOMEM; ++ ++ for (i = 0; i < HASH_STRENGTH_FULL; i++) ++ random_nums[i] = i; ++ ++ for (i = 0; i < HASH_STRENGTH_FULL; i++) { ++ unsigned long rand_range, swap_index, tmp; ++ ++ rand_range = HASH_STRENGTH_FULL - i; ++ swap_index = i + prandom_u32() % rand_range; ++ tmp = random_nums[i]; ++ random_nums[i] = random_nums[swap_index]; ++ random_nums[swap_index] = tmp; ++ } ++ ++ rshash_state.state = RSHASH_NEW; ++ rshash_state.below_count = 0; ++ rshash_state.lookup_window_index = 0; ++ ++ return cal_positive_negative_costs(); ++} ++ ++static int __init uksm_slab_init(void) ++{ ++ rmap_item_cache = UKSM_KMEM_CACHE(rmap_item, 0); ++ if (!rmap_item_cache) ++ goto out; ++ ++ stable_node_cache = UKSM_KMEM_CACHE(stable_node, 0); ++ if (!stable_node_cache) ++ goto out_free1; ++ ++ node_vma_cache = UKSM_KMEM_CACHE(node_vma, 0); ++ if (!node_vma_cache) ++ goto out_free2; ++ ++ vma_slot_cache = UKSM_KMEM_CACHE(vma_slot, 0); ++ if (!vma_slot_cache) ++ goto out_free3; ++ ++ tree_node_cache = UKSM_KMEM_CACHE(tree_node, 0); ++ if (!tree_node_cache) ++ goto out_free4; ++ ++ return 0; ++ ++out_free4: ++ kmem_cache_destroy(vma_slot_cache); ++out_free3: ++ kmem_cache_destroy(node_vma_cache); ++out_free2: ++ kmem_cache_destroy(stable_node_cache); ++out_free1: ++ kmem_cache_destroy(rmap_item_cache); ++out: ++ return -ENOMEM; ++} ++ ++static void __init uksm_slab_free(void) ++{ ++ kmem_cache_destroy(stable_node_cache); ++ kmem_cache_destroy(rmap_item_cache); ++ kmem_cache_destroy(node_vma_cache); ++ kmem_cache_destroy(vma_slot_cache); ++ kmem_cache_destroy(tree_node_cache); ++} ++ ++/* Common interface to ksm, different to it. */ ++int ksm_madvise(struct vm_area_struct *vma, unsigned long start, ++ unsigned long end, int advice, unsigned long *vm_flags) ++{ ++ int err; ++ ++ switch (advice) { ++ case MADV_MERGEABLE: ++ return 0; /* just ignore the advice */ ++ ++ case MADV_UNMERGEABLE: ++ if (!(*vm_flags & VM_MERGEABLE)) ++ return 0; /* just ignore the advice */ ++ ++ if (vma->anon_vma) { ++ err = unmerge_uksm_pages(vma, start, end); ++ if (err) ++ return err; ++ } ++ ++ uksm_remove_vma(vma); ++ *vm_flags &= ~VM_MERGEABLE; ++ break; ++ } ++ ++ return 0; ++} ++ ++/* Common interface to ksm, actually the same. */ ++struct page *ksm_might_need_to_copy(struct page *page, ++ struct vm_area_struct *vma, unsigned long address) ++{ ++ struct anon_vma *anon_vma = page_anon_vma(page); ++ struct page *new_page; ++ ++ if (PageKsm(page)) { ++ if (page_stable_node(page)) ++ return page; /* no need to copy it */ ++ } else if (!anon_vma) { ++ return page; /* no need to copy it */ ++ } else if (anon_vma->root == vma->anon_vma->root && ++ page->index == linear_page_index(vma, address)) { ++ return page; /* still no need to copy it */ ++ } ++ if (!PageUptodate(page)) ++ return page; /* let do_swap_page report the error */ ++ ++ new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address); ++ if (new_page) { ++ copy_user_highpage(new_page, page, address, vma); ++ ++ SetPageDirty(new_page); ++ __SetPageUptodate(new_page); ++ __set_page_locked(new_page); ++ } ++ ++ return new_page; ++} ++ ++static int __init uksm_init(void) ++{ ++ struct task_struct *uksm_thread; ++ int err; ++ ++ uksm_sleep_jiffies = msecs_to_jiffies(100); ++ uksm_sleep_saved = uksm_sleep_jiffies; ++ ++ slot_tree_init(); ++ init_scan_ladder(); ++ ++ ++ err = init_random_sampling(); ++ if (err) ++ goto out_free2; ++ ++ err = uksm_slab_init(); ++ if (err) ++ goto out_free1; ++ ++ err = init_zeropage_hash_table(); ++ if (err) ++ goto out_free0; ++ ++ uksm_thread = kthread_run(uksm_scan_thread, NULL, "uksmd"); ++ if (IS_ERR(uksm_thread)) { ++ printk(KERN_ERR "uksm: creating kthread failed\n"); ++ err = PTR_ERR(uksm_thread); ++ goto out_free; ++ } ++ ++#ifdef CONFIG_SYSFS ++ err = sysfs_create_group(mm_kobj, &uksm_attr_group); ++ if (err) { ++ printk(KERN_ERR "uksm: register sysfs failed\n"); ++ kthread_stop(uksm_thread); ++ goto out_free; ++ } ++#else ++ uksm_run = UKSM_RUN_MERGE; /* no way for user to start it */ ++ ++#endif /* CONFIG_SYSFS */ ++ ++#ifdef CONFIG_MEMORY_HOTREMOVE ++ /* ++ * Choose a high priority since the callback takes uksm_thread_mutex: ++ * later callbacks could only be taking locks which nest within that. ++ */ ++ hotplug_memory_notifier(uksm_memory_callback, 100); ++#endif ++ return 0; ++ ++out_free: ++ kfree(zero_hash_table); ++out_free0: ++ uksm_slab_free(); ++out_free1: ++ kfree(random_nums); ++out_free2: ++ kfree(uksm_scan_ladder); ++ return err; ++} ++ ++#ifdef MODULE ++module_init(uksm_init) ++#else ++late_initcall(uksm_init); ++#endif ++ +diff --git a/mm/vmstat.c b/mm/vmstat.c +index 9bb3145..885419c 100644 +--- a/mm/vmstat.c ++++ b/mm/vmstat.c +@@ -772,6 +772,9 @@ const char * const vmstat_text[] = { + #endif + "nr_anon_transparent_hugepages", + "nr_free_cma", ++#ifdef CONFIG_UKSM ++ "nr_uksm_zero_pages", ++#endif + "nr_dirty_threshold", + "nr_dirty_background_threshold", +