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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2011-11-15 17:14:39 +0100
committerIngo Molnar <mingo@elte.hu>2011-11-17 12:20:22 +0100
commit391e43da797a96aeb65410281891f6d0b0e9611c (patch)
tree0ce6784525a5a8f75b377170cf1a7d60abccea29 /kernel/sched_fair.c
parent029632fbb7b7c9d85063cc9eb470de6c54873df3 (diff)
downloadlinux-linaro-stable-391e43da797a96aeb65410281891f6d0b0e9611c.tar.gz
sched: Move all scheduler bits into kernel/sched/
There's too many sched*.[ch] files in kernel/, give them their own directory. (No code changed, other than Makefile glue added.) Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/sched_fair.c')
-rw-r--r--kernel/sched_fair.c5601
1 files changed, 0 insertions, 5601 deletions
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
deleted file mode 100644
index cd3b64219d9f..000000000000
--- a/kernel/sched_fair.c
+++ /dev/null
@@ -1,5601 +0,0 @@
-/*
- * Completely Fair Scheduling (CFS) Class (SCHED_NORMAL/SCHED_BATCH)
- *
- * Copyright (C) 2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
- *
- * Interactivity improvements by Mike Galbraith
- * (C) 2007 Mike Galbraith <efault@gmx.de>
- *
- * Various enhancements by Dmitry Adamushko.
- * (C) 2007 Dmitry Adamushko <dmitry.adamushko@gmail.com>
- *
- * Group scheduling enhancements by Srivatsa Vaddagiri
- * Copyright IBM Corporation, 2007
- * Author: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
- *
- * Scaled math optimizations by Thomas Gleixner
- * Copyright (C) 2007, Thomas Gleixner <tglx@linutronix.de>
- *
- * Adaptive scheduling granularity, math enhancements by Peter Zijlstra
- * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
- */
-
-#include <linux/latencytop.h>
-#include <linux/sched.h>
-#include <linux/cpumask.h>
-#include <linux/slab.h>
-#include <linux/profile.h>
-#include <linux/interrupt.h>
-
-#include <trace/events/sched.h>
-
-#include "sched.h"
-
-/*
- * Targeted preemption latency for CPU-bound tasks:
- * (default: 6ms * (1 + ilog(ncpus)), units: nanoseconds)
- *
- * NOTE: this latency value is not the same as the concept of
- * 'timeslice length' - timeslices in CFS are of variable length
- * and have no persistent notion like in traditional, time-slice
- * based scheduling concepts.
- *
- * (to see the precise effective timeslice length of your workload,
- * run vmstat and monitor the context-switches (cs) field)
- */
-unsigned int sysctl_sched_latency = 6000000ULL;
-unsigned int normalized_sysctl_sched_latency = 6000000ULL;
-
-/*
- * The initial- and re-scaling of tunables is configurable
- * (default SCHED_TUNABLESCALING_LOG = *(1+ilog(ncpus))
- *
- * Options are:
- * SCHED_TUNABLESCALING_NONE - unscaled, always *1
- * SCHED_TUNABLESCALING_LOG - scaled logarithmical, *1+ilog(ncpus)
- * SCHED_TUNABLESCALING_LINEAR - scaled linear, *ncpus
- */
-enum sched_tunable_scaling sysctl_sched_tunable_scaling
- = SCHED_TUNABLESCALING_LOG;
-
-/*
- * Minimal preemption granularity for CPU-bound tasks:
- * (default: 0.75 msec * (1 + ilog(ncpus)), units: nanoseconds)
- */
-unsigned int sysctl_sched_min_granularity = 750000ULL;
-unsigned int normalized_sysctl_sched_min_granularity = 750000ULL;
-
-/*
- * is kept at sysctl_sched_latency / sysctl_sched_min_granularity
- */
-static unsigned int sched_nr_latency = 8;
-
-/*
- * After fork, child runs first. If set to 0 (default) then
- * parent will (try to) run first.
- */
-unsigned int sysctl_sched_child_runs_first __read_mostly;
-
-/*
- * SCHED_OTHER wake-up granularity.
- * (default: 1 msec * (1 + ilog(ncpus)), units: nanoseconds)
- *
- * This option delays the preemption effects of decoupled workloads
- * and reduces their over-scheduling. Synchronous workloads will still
- * have immediate wakeup/sleep latencies.
- */
-unsigned int sysctl_sched_wakeup_granularity = 1000000UL;
-unsigned int normalized_sysctl_sched_wakeup_granularity = 1000000UL;
-
-const_debug unsigned int sysctl_sched_migration_cost = 500000UL;
-
-/*
- * The exponential sliding window over which load is averaged for shares
- * distribution.
- * (default: 10msec)
- */
-unsigned int __read_mostly sysctl_sched_shares_window = 10000000UL;
-
-#ifdef CONFIG_CFS_BANDWIDTH
-/*
- * Amount of runtime to allocate from global (tg) to local (per-cfs_rq) pool
- * each time a cfs_rq requests quota.
- *
- * Note: in the case that the slice exceeds the runtime remaining (either due
- * to consumption or the quota being specified to be smaller than the slice)
- * we will always only issue the remaining available time.
- *
- * default: 5 msec, units: microseconds
- */
-unsigned int sysctl_sched_cfs_bandwidth_slice = 5000UL;
-#endif
-
-/*
- * Increase the granularity value when there are more CPUs,
- * because with more CPUs the 'effective latency' as visible
- * to users decreases. But the relationship is not linear,
- * so pick a second-best guess by going with the log2 of the
- * number of CPUs.
- *
- * This idea comes from the SD scheduler of Con Kolivas:
- */
-static int get_update_sysctl_factor(void)
-{
- unsigned int cpus = min_t(int, num_online_cpus(), 8);
- unsigned int factor;
-
- switch (sysctl_sched_tunable_scaling) {
- case SCHED_TUNABLESCALING_NONE:
- factor = 1;
- break;
- case SCHED_TUNABLESCALING_LINEAR:
- factor = cpus;
- break;
- case SCHED_TUNABLESCALING_LOG:
- default:
- factor = 1 + ilog2(cpus);
- break;
- }
-
- return factor;
-}
-
-static void update_sysctl(void)
-{
- unsigned int factor = get_update_sysctl_factor();
-
-#define SET_SYSCTL(name) \
- (sysctl_##name = (factor) * normalized_sysctl_##name)
- SET_SYSCTL(sched_min_granularity);
- SET_SYSCTL(sched_latency);
- SET_SYSCTL(sched_wakeup_granularity);
-#undef SET_SYSCTL
-}
-
-void sched_init_granularity(void)
-{
- update_sysctl();
-}
-
-#if BITS_PER_LONG == 32
-# define WMULT_CONST (~0UL)
-#else
-# define WMULT_CONST (1UL << 32)
-#endif
-
-#define WMULT_SHIFT 32
-
-/*
- * Shift right and round:
- */
-#define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y))
-
-/*
- * delta *= weight / lw
- */
-static unsigned long
-calc_delta_mine(unsigned long delta_exec, unsigned long weight,
- struct load_weight *lw)
-{
- u64 tmp;
-
- /*
- * weight can be less than 2^SCHED_LOAD_RESOLUTION for task group sched
- * entities since MIN_SHARES = 2. Treat weight as 1 if less than
- * 2^SCHED_LOAD_RESOLUTION.
- */
- if (likely(weight > (1UL << SCHED_LOAD_RESOLUTION)))
- tmp = (u64)delta_exec * scale_load_down(weight);
- else
- tmp = (u64)delta_exec;
-
- if (!lw->inv_weight) {
- unsigned long w = scale_load_down(lw->weight);
-
- if (BITS_PER_LONG > 32 && unlikely(w >= WMULT_CONST))
- lw->inv_weight = 1;
- else if (unlikely(!w))
- lw->inv_weight = WMULT_CONST;
- else
- lw->inv_weight = WMULT_CONST / w;
- }
-
- /*
- * Check whether we'd overflow the 64-bit multiplication:
- */
- if (unlikely(tmp > WMULT_CONST))
- tmp = SRR(SRR(tmp, WMULT_SHIFT/2) * lw->inv_weight,
- WMULT_SHIFT/2);
- else
- tmp = SRR(tmp * lw->inv_weight, WMULT_SHIFT);
-
- return (unsigned long)min(tmp, (u64)(unsigned long)LONG_MAX);
-}
-
-
-const struct sched_class fair_sched_class;
-
-/**************************************************************
- * CFS operations on generic schedulable entities:
- */
-
-#ifdef CONFIG_FAIR_GROUP_SCHED
-
-/* cpu runqueue to which this cfs_rq is attached */
-static inline struct rq *rq_of(struct cfs_rq *cfs_rq)
-{
- return cfs_rq->rq;
-}
-
-/* An entity is a task if it doesn't "own" a runqueue */
-#define entity_is_task(se) (!se->my_q)
-
-static inline struct task_struct *task_of(struct sched_entity *se)
-{
-#ifdef CONFIG_SCHED_DEBUG
- WARN_ON_ONCE(!entity_is_task(se));
-#endif
- return container_of(se, struct task_struct, se);
-}
-
-/* Walk up scheduling entities hierarchy */
-#define for_each_sched_entity(se) \
- for (; se; se = se->parent)
-
-static inline struct cfs_rq *task_cfs_rq(struct task_struct *p)
-{
- return p->se.cfs_rq;
-}
-
-/* runqueue on which this entity is (to be) queued */
-static inline struct cfs_rq *cfs_rq_of(struct sched_entity *se)
-{
- return se->cfs_rq;
-}
-
-/* runqueue "owned" by this group */
-static inline struct cfs_rq *group_cfs_rq(struct sched_entity *grp)
-{
- return grp->my_q;
-}
-
-static inline void list_add_leaf_cfs_rq(struct cfs_rq *cfs_rq)
-{
- if (!cfs_rq->on_list) {
- /*
- * Ensure we either appear before our parent (if already
- * enqueued) or force our parent to appear after us when it is
- * enqueued. The fact that we always enqueue bottom-up
- * reduces this to two cases.
- */
- if (cfs_rq->tg->parent &&
- cfs_rq->tg->parent->cfs_rq[cpu_of(rq_of(cfs_rq))]->on_list) {
- list_add_rcu(&cfs_rq->leaf_cfs_rq_list,
- &rq_of(cfs_rq)->leaf_cfs_rq_list);
- } else {
- list_add_tail_rcu(&cfs_rq->leaf_cfs_rq_list,
- &rq_of(cfs_rq)->leaf_cfs_rq_list);
- }
-
- cfs_rq->on_list = 1;
- }
-}
-
-static inline void list_del_leaf_cfs_rq(struct cfs_rq *cfs_rq)
-{
- if (cfs_rq->on_list) {
- list_del_rcu(&cfs_rq->leaf_cfs_rq_list);
- cfs_rq->on_list = 0;
- }
-}
-
-/* Iterate thr' all leaf cfs_rq's on a runqueue */
-#define for_each_leaf_cfs_rq(rq, cfs_rq) \
- list_for_each_entry_rcu(cfs_rq, &rq->leaf_cfs_rq_list, leaf_cfs_rq_list)
-
-/* Do the two (enqueued) entities belong to the same group ? */
-static inline int
-is_same_group(struct sched_entity *se, struct sched_entity *pse)
-{
- if (se->cfs_rq == pse->cfs_rq)
- return 1;
-
- return 0;
-}
-
-static inline struct sched_entity *parent_entity(struct sched_entity *se)
-{
- return se->parent;
-}
-
-/* return depth at which a sched entity is present in the hierarchy */
-static inline int depth_se(struct sched_entity *se)
-{
- int depth = 0;
-
- for_each_sched_entity(se)
- depth++;
-
- return depth;
-}
-
-static void
-find_matching_se(struct sched_entity **se, struct sched_entity **pse)
-{
- int se_depth, pse_depth;
-
- /*
- * preemption test can be made between sibling entities who are in the
- * same cfs_rq i.e who have a common parent. Walk up the hierarchy of
- * both tasks until we find their ancestors who are siblings of common
- * parent.
- */
-
- /* First walk up until both entities are at same depth */
- se_depth = depth_se(*se);
- pse_depth = depth_se(*pse);
-
- while (se_depth > pse_depth) {
- se_depth--;
- *se = parent_entity(*se);
- }
-
- while (pse_depth > se_depth) {
- pse_depth--;
- *pse = parent_entity(*pse);
- }
-
- while (!is_same_group(*se, *pse)) {
- *se = parent_entity(*se);
- *pse = parent_entity(*pse);
- }
-}
-
-#else /* !CONFIG_FAIR_GROUP_SCHED */
-
-static inline struct task_struct *task_of(struct sched_entity *se)
-{
- return container_of(se, struct task_struct, se);
-}
-
-static inline struct rq *rq_of(struct cfs_rq *cfs_rq)
-{
- return container_of(cfs_rq, struct rq, cfs);
-}
-
-#define entity_is_task(se) 1
-
-#define for_each_sched_entity(se) \
- for (; se; se = NULL)
-
-static inline struct cfs_rq *task_cfs_rq(struct task_struct *p)
-{
- return &task_rq(p)->cfs;
-}
-
-static inline struct cfs_rq *cfs_rq_of(struct sched_entity *se)
-{
- struct task_struct *p = task_of(se);
- struct rq *rq = task_rq(p);
-
- return &rq->cfs;
-}
-
-/* runqueue "owned" by this group */
-static inline struct cfs_rq *group_cfs_rq(struct sched_entity *grp)
-{
- return NULL;
-}
-
-static inline void list_add_leaf_cfs_rq(struct cfs_rq *cfs_rq)
-{
-}
-
-static inline void list_del_leaf_cfs_rq(struct cfs_rq *cfs_rq)
-{
-}
-
-#define for_each_leaf_cfs_rq(rq, cfs_rq) \
- for (cfs_rq = &rq->cfs; cfs_rq; cfs_rq = NULL)
-
-static inline int
-is_same_group(struct sched_entity *se, struct sched_entity *pse)
-{
- return 1;
-}
-
-static inline struct sched_entity *parent_entity(struct sched_entity *se)
-{
- return NULL;
-}
-
-static inline void
-find_matching_se(struct sched_entity **se, struct sched_entity **pse)
-{
-}
-
-#endif /* CONFIG_FAIR_GROUP_SCHED */
-
-static void account_cfs_rq_runtime(struct cfs_rq *cfs_rq,
- unsigned long delta_exec);
-
-/**************************************************************
- * Scheduling class tree data structure manipulation methods:
- */
-
-static inline u64 max_vruntime(u64 min_vruntime, u64 vruntime)
-{
- s64 delta = (s64)(vruntime - min_vruntime);
- if (delta > 0)
- min_vruntime = vruntime;
-
- return min_vruntime;
-}
-
-static inline u64 min_vruntime(u64 min_vruntime, u64 vruntime)
-{
- s64 delta = (s64)(vruntime - min_vruntime);
- if (delta < 0)
- min_vruntime = vruntime;
-
- return min_vruntime;
-}
-
-static inline int entity_before(struct sched_entity *a,
- struct sched_entity *b)
-{
- return (s64)(a->vruntime - b->vruntime) < 0;
-}
-
-static void update_min_vruntime(struct cfs_rq *cfs_rq)
-{
- u64 vruntime = cfs_rq->min_vruntime;
-
- if (cfs_rq->curr)
- vruntime = cfs_rq->curr->vruntime;
-
- if (cfs_rq->rb_leftmost) {
- struct sched_entity *se = rb_entry(cfs_rq->rb_leftmost,
- struct sched_entity,
- run_node);
-
- if (!cfs_rq->curr)
- vruntime = se->vruntime;
- else
- vruntime = min_vruntime(vruntime, se->vruntime);
- }
-
- cfs_rq->min_vruntime = max_vruntime(cfs_rq->min_vruntime, vruntime);
-#ifndef CONFIG_64BIT
- smp_wmb();
- cfs_rq->min_vruntime_copy = cfs_rq->min_vruntime;
-#endif
-}
-
-/*
- * Enqueue an entity into the rb-tree:
- */
-static void __enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
-{
- struct rb_node **link = &cfs_rq->tasks_timeline.rb_node;
- struct rb_node *parent = NULL;
- struct sched_entity *entry;
- int leftmost = 1;
-
- /*
- * Find the right place in the rbtree:
- */
- while (*link) {
- parent = *link;
- entry = rb_entry(parent, struct sched_entity, run_node);
- /*
- * We dont care about collisions. Nodes with
- * the same key stay together.
- */
- if (entity_before(se, entry)) {
- link = &parent->rb_left;
- } else {
- link = &parent->rb_right;
- leftmost = 0;
- }
- }
-
- /*
- * Maintain a cache of leftmost tree entries (it is frequently
- * used):
- */
- if (leftmost)
- cfs_rq->rb_leftmost = &se->run_node;
-
- rb_link_node(&se->run_node, parent, link);
- rb_insert_color(&se->run_node, &cfs_rq->tasks_timeline);
-}
-
-static void __dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
-{
- if (cfs_rq->rb_leftmost == &se->run_node) {
- struct rb_node *next_node;
-
- next_node = rb_next(&se->run_node);
- cfs_rq->rb_leftmost = next_node;
- }
-
- rb_erase(&se->run_node, &cfs_rq->tasks_timeline);
-}
-
-struct sched_entity *__pick_first_entity(struct cfs_rq *cfs_rq)
-{
- struct rb_node *left = cfs_rq->rb_leftmost;
-
- if (!left)
- return NULL;
-
- return rb_entry(left, struct sched_entity, run_node);
-}
-
-static struct sched_entity *__pick_next_entity(struct sched_entity *se)
-{
- struct rb_node *next = rb_next(&se->run_node);
-
- if (!next)
- return NULL;
-
- return rb_entry(next, struct sched_entity, run_node);
-}
-
-#ifdef CONFIG_SCHED_DEBUG
-struct sched_entity *__pick_last_entity(struct cfs_rq *cfs_rq)
-{
- struct rb_node *last = rb_last(&cfs_rq->tasks_timeline);
-
- if (!last)
- return NULL;
-
- return rb_entry(last, struct sched_entity, run_node);
-}
-
-/**************************************************************
- * Scheduling class statistics methods:
- */
-
-int sched_proc_update_handler(struct ctl_table *table, int write,
- void __user *buffer, size_t *lenp,
- loff_t *ppos)
-{
- int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
- int factor = get_update_sysctl_factor();
-
- if (ret || !write)
- return ret;
-
- sched_nr_latency = DIV_ROUND_UP(sysctl_sched_latency,
- sysctl_sched_min_granularity);
-
-#define WRT_SYSCTL(name) \
- (normalized_sysctl_##name = sysctl_##name / (factor))
- WRT_SYSCTL(sched_min_granularity);
- WRT_SYSCTL(sched_latency);
- WRT_SYSCTL(sched_wakeup_granularity);
-#undef WRT_SYSCTL
-
- return 0;
-}
-#endif
-
-/*
- * delta /= w
- */
-static inline unsigned long
-calc_delta_fair(unsigned long delta, struct sched_entity *se)
-{
- if (unlikely(se->load.weight != NICE_0_LOAD))
- delta = calc_delta_mine(delta, NICE_0_LOAD, &se->load);
-
- return delta;
-}
-
-/*
- * The idea is to set a period in which each task runs once.
- *
- * When there are too many tasks (sysctl_sched_nr_latency) we have to stretch
- * this period because otherwise the slices get too small.
- *
- * p = (nr <= nl) ? l : l*nr/nl
- */
-static u64 __sched_period(unsigned long nr_running)
-{
- u64 period = sysctl_sched_latency;
- unsigned long nr_latency = sched_nr_latency;
-
- if (unlikely(nr_running > nr_latency)) {
- period = sysctl_sched_min_granularity;
- period *= nr_running;
- }
-
- return period;
-}
-
-/*
- * We calculate the wall-time slice from the period by taking a part
- * proportional to the weight.
- *
- * s = p*P[w/rw]
- */
-static u64 sched_slice(struct cfs_rq *cfs_rq, struct sched_entity *se)
-{
- u64 slice = __sched_period(cfs_rq->nr_running + !se->on_rq);
-
- for_each_sched_entity(se) {
- struct load_weight *load;
- struct load_weight lw;
-
- cfs_rq = cfs_rq_of(se);
- load = &cfs_rq->load;
-
- if (unlikely(!se->on_rq)) {
- lw = cfs_rq->load;
-
- update_load_add(&lw, se->load.weight);
- load = &lw;
- }
- slice = calc_delta_mine(slice, se->load.weight, load);
- }
- return slice;
-}
-
-/*
- * We calculate the vruntime slice of a to be inserted task
- *
- * vs = s/w
- */
-static u64 sched_vslice(struct cfs_rq *cfs_rq, struct sched_entity *se)
-{
- return calc_delta_fair(sched_slice(cfs_rq, se), se);
-}
-
-static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update);
-static void update_cfs_shares(struct cfs_rq *cfs_rq);
-
-/*
- * Update the current task's runtime statistics. Skip current tasks that
- * are not in our scheduling class.
- */
-static inline void
-__update_curr(struct cfs_rq *cfs_rq, struct sched_entity *curr,
- unsigned long delta_exec)
-{
- unsigned long delta_exec_weighted;
-
- schedstat_set(curr->statistics.exec_max,
- max((u64)delta_exec, curr->statistics.exec_max));
-
- curr->sum_exec_runtime += delta_exec;
- schedstat_add(cfs_rq, exec_clock, delta_exec);
- delta_exec_weighted = calc_delta_fair(delta_exec, curr);
-
- curr->vruntime += delta_exec_weighted;
- update_min_vruntime(cfs_rq);
-
-#if defined CONFIG_SMP && defined CONFIG_FAIR_GROUP_SCHED
- cfs_rq->load_unacc_exec_time += delta_exec;
-#endif
-}
-
-static void update_curr(struct cfs_rq *cfs_rq)
-{
- struct sched_entity *curr = cfs_rq->curr;
- u64 now = rq_of(cfs_rq)->clock_task;
- unsigned long delta_exec;
-
- if (unlikely(!curr))
- return;
-
- /*
- * Get the amount of time the current task was running
- * since the last time we changed load (this cannot
- * overflow on 32 bits):
- */
- delta_exec = (unsigned long)(now - curr->exec_start);
- if (!delta_exec)
- return;
-
- __update_curr(cfs_rq, curr, delta_exec);
- curr->exec_start = now;
-
- if (entity_is_task(curr)) {
- struct task_struct *curtask = task_of(curr);
-
- trace_sched_stat_runtime(curtask, delta_exec, curr->vruntime);
- cpuacct_charge(curtask, delta_exec);
- account_group_exec_runtime(curtask, delta_exec);
- }
-
- account_cfs_rq_runtime(cfs_rq, delta_exec);
-}
-
-static inline void
-update_stats_wait_start(struct cfs_rq *cfs_rq, struct sched_entity *se)
-{
- schedstat_set(se->statistics.wait_start, rq_of(cfs_rq)->clock);
-}
-
-/*
- * Task is being enqueued - update stats:
- */
-static void update_stats_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se)
-{
- /*
- * Are we enqueueing a waiting task? (for current tasks
- * a dequeue/enqueue event is a NOP)
- */
- if (se != cfs_rq->curr)
- update_stats_wait_start(cfs_rq, se);
-}
-
-static void
-update_stats_wait_end(struct cfs_rq *cfs_rq, struct sched_entity *se)
-{
- schedstat_set(se->statistics.wait_max, max(se->statistics.wait_max,
- rq_of(cfs_rq)->clock - se->statistics.wait_start));
- schedstat_set(se->statistics.wait_count, se->statistics.wait_count + 1);
- schedstat_set(se->statistics.wait_sum, se->statistics.wait_sum +
- rq_of(cfs_rq)->clock - se->statistics.wait_start);
-#ifdef CONFIG_SCHEDSTATS
- if (entity_is_task(se)) {
- trace_sched_stat_wait(task_of(se),
- rq_of(cfs_rq)->clock - se->statistics.wait_start);
- }
-#endif
- schedstat_set(se->statistics.wait_start, 0);
-}
-
-static inline void
-update_stats_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se)
-{
- /*
- * Mark the end of the wait period if dequeueing a
- * waiting task:
- */
- if (se != cfs_rq->curr)
- update_stats_wait_end(cfs_rq, se);
-}
-
-/*
- * We are picking a new current task - update its stats:
- */
-static inline void
-update_stats_curr_start(struct cfs_rq *cfs_rq, struct sched_entity *se)
-{
- /*
- * We are starting a new run period:
- */
- se->exec_start = rq_of(cfs_rq)->clock_task;
-}
-
-/**************************************************
- * Scheduling class queueing methods:
- */
-
-#if defined CONFIG_SMP && defined CONFIG_FAIR_GROUP_SCHED
-static void
-add_cfs_task_weight(struct cfs_rq *cfs_rq, unsigned long weight)
-{
- cfs_rq->task_weight += weight;
-}
-#else
-static inline void
-add_cfs_task_weight(struct cfs_rq *cfs_rq, unsigned long weight)
-{
-}
-#endif
-
-static void
-account_entity_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se)
-{
- update_load_add(&cfs_rq->load, se->load.weight);
- if (!parent_entity(se))
- update_load_add(&rq_of(cfs_rq)->load, se->load.weight);
- if (entity_is_task(se)) {
- add_cfs_task_weight(cfs_rq, se->load.weight);
- list_add(&se->group_node, &cfs_rq->tasks);
- }
- cfs_rq->nr_running++;
-}
-
-static void
-account_entity_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se)
-{
- update_load_sub(&cfs_rq->load, se->load.weight);
- if (!parent_entity(se))
- update_load_sub(&rq_of(cfs_rq)->load, se->load.weight);
- if (entity_is_task(se)) {
- add_cfs_task_weight(cfs_rq, -se->load.weight);
- list_del_init(&se->group_node);
- }
- cfs_rq->nr_running--;
-}
-
-#ifdef CONFIG_FAIR_GROUP_SCHED
-/* we need this in update_cfs_load and load-balance functions below */
-static inline int throttled_hierarchy(struct cfs_rq *cfs_rq);
-# ifdef CONFIG_SMP
-static void update_cfs_rq_load_contribution(struct cfs_rq *cfs_rq,
- int global_update)
-{
- struct task_group *tg = cfs_rq->tg;
- long load_avg;
-
- load_avg = div64_u64(cfs_rq->load_avg, cfs_rq->load_period+1);
- load_avg -= cfs_rq->load_contribution;
-
- if (global_update || abs(load_avg) > cfs_rq->load_contribution / 8) {
- atomic_add(load_avg, &tg->load_weight);
- cfs_rq->load_contribution += load_avg;
- }
-}
-
-static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update)
-{
- u64 period = sysctl_sched_shares_window;
- u64 now, delta;
- unsigned long load = cfs_rq->load.weight;
-
- if (cfs_rq->tg == &root_task_group || throttled_hierarchy(cfs_rq))
- return;
-
- now = rq_of(cfs_rq)->clock_task;
- delta = now - cfs_rq->load_stamp;
-
- /* truncate load history at 4 idle periods */
- if (cfs_rq->load_stamp > cfs_rq->load_last &&
- now - cfs_rq->load_last > 4 * period) {
- cfs_rq->load_period = 0;
- cfs_rq->load_avg = 0;
- delta = period - 1;
- }
-
- cfs_rq->load_stamp = now;
- cfs_rq->load_unacc_exec_time = 0;
- cfs_rq->load_period += delta;
- if (load) {
- cfs_rq->load_last = now;
- cfs_rq->load_avg += delta * load;
- }
-
- /* consider updating load contribution on each fold or truncate */
- if (global_update || cfs_rq->load_period > period
- || !cfs_rq->load_period)
- update_cfs_rq_load_contribution(cfs_rq, global_update);
-
- while (cfs_rq->load_period > period) {
- /*
- * Inline assembly required to prevent the compiler
- * optimising this loop into a divmod call.
- * See __iter_div_u64_rem() for another example of this.
- */
- asm("" : "+rm" (cfs_rq->load_period));
- cfs_rq->load_period /= 2;
- cfs_rq->load_avg /= 2;
- }
-
- if (!cfs_rq->curr && !cfs_rq->nr_running && !cfs_rq->load_avg)
- list_del_leaf_cfs_rq(cfs_rq);
-}
-
-static inline long calc_tg_weight(struct task_group *tg, struct cfs_rq *cfs_rq)
-{
- long tg_weight;
-
- /*
- * Use this CPU's actual weight instead of the last load_contribution
- * to gain a more accurate current total weight. See
- * update_cfs_rq_load_contribution().
- */
- tg_weight = atomic_read(&tg->load_weight);
- tg_weight -= cfs_rq->load_contribution;
- tg_weight += cfs_rq->load.weight;
-
- return tg_weight;
-}
-
-static long calc_cfs_shares(struct cfs_rq *cfs_rq, struct task_group *tg)
-{
- long tg_weight, load, shares;
-
- tg_weight = calc_tg_weight(tg, cfs_rq);
- load = cfs_rq->load.weight;
-
- shares = (tg->shares * load);
- if (tg_weight)
- shares /= tg_weight;
-
- if (shares < MIN_SHARES)
- shares = MIN_SHARES;
- if (shares > tg->shares)
- shares = tg->shares;
-
- return shares;
-}
-
-static void update_entity_shares_tick(struct cfs_rq *cfs_rq)
-{
- if (cfs_rq->load_unacc_exec_time > sysctl_sched_shares_window) {
- update_cfs_load(cfs_rq, 0);
- update_cfs_shares(cfs_rq);
- }
-}
-# else /* CONFIG_SMP */
-static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update)
-{
-}
-
-static inline long calc_cfs_shares(struct cfs_rq *cfs_rq, struct task_group *tg)
-{
- return tg->shares;
-}
-
-static inline void update_entity_shares_tick(struct cfs_rq *cfs_rq)
-{
-}
-# endif /* CONFIG_SMP */
-static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se,
- unsigned long weight)
-{
- if (se->on_rq) {
- /* commit outstanding execution time */
- if (cfs_rq->curr == se)
- update_curr(cfs_rq);
- account_entity_dequeue(cfs_rq, se);
- }
-
- update_load_set(&se->load, weight);
-
- if (se->on_rq)
- account_entity_enqueue(cfs_rq, se);
-}
-
-static void update_cfs_shares(struct cfs_rq *cfs_rq)
-{
- struct task_group *tg;
- struct sched_entity *se;
- long shares;
-
- tg = cfs_rq->tg;
- se = tg->se[cpu_of(rq_of(cfs_rq))];
- if (!se || throttled_hierarchy(cfs_rq))
- return;
-#ifndef CONFIG_SMP
- if (likely(se->load.weight == tg->shares))
- return;
-#endif
- shares = calc_cfs_shares(cfs_rq, tg);
-
- reweight_entity(cfs_rq_of(se), se, shares);
-}
-#else /* CONFIG_FAIR_GROUP_SCHED */
-static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update)
-{
-}
-
-static inline void update_cfs_shares(struct cfs_rq *cfs_rq)
-{
-}
-
-static inline void update_entity_shares_tick(struct cfs_rq *cfs_rq)
-{
-}
-#endif /* CONFIG_FAIR_GROUP_SCHED */
-
-static void enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se)
-{
-#ifdef CONFIG_SCHEDSTATS
- struct task_struct *tsk = NULL;
-
- if (entity_is_task(se))
- tsk = task_of(se);
-
- if (se->statistics.sleep_start) {
- u64 delta = rq_of(cfs_rq)->clock - se->statistics.sleep_start;
-
- if ((s64)delta < 0)
- delta = 0;
-
- if (unlikely(delta > se->statistics.sleep_max))
- se->statistics.sleep_max = delta;
-
- se->statistics.sleep_start = 0;
- se->statistics.sum_sleep_runtime += delta;
-
- if (tsk) {
- account_scheduler_latency(tsk, delta >> 10, 1);
- trace_sched_stat_sleep(tsk, delta);
- }
- }
- if (se->statistics.block_start) {
- u64 delta = rq_of(cfs_rq)->clock - se->statistics.block_start;
-
- if ((s64)delta < 0)
- delta = 0;
-
- if (unlikely(delta > se->statistics.block_max))
- se->statistics.block_max = delta;
-
- se->statistics.block_start = 0;
- se->statistics.sum_sleep_runtime += delta;
-
- if (tsk) {
- if (tsk->in_iowait) {
- se->statistics.iowait_sum += delta;
- se->statistics.iowait_count++;
- trace_sched_stat_iowait(tsk, delta);
- }
-
- /*
- * Blocking 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)) {
- profile_hits(SLEEP_PROFILING,
- (void *)get_wchan(tsk),
- delta >> 20);
- }
- account_scheduler_latency(tsk, delta >> 10, 0);
- }
- }
-#endif
-}
-
-static void check_spread(struct cfs_rq *cfs_rq, struct sched_entity *se)
-{
-#ifdef CONFIG_SCHED_DEBUG
- s64 d = se->vruntime - cfs_rq->min_vruntime;
-
- if (d < 0)
- d = -d;
-
- if (d > 3*sysctl_sched_latency)
- schedstat_inc(cfs_rq, nr_spread_over);
-#endif
-}
-
-static void
-place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial)
-{
- u64 vruntime = cfs_rq->min_vruntime;
-
- /*
- * The 'current' period is already promised to the current tasks,
- * however the extra weight of the new task will slow them down a
- * little, place the new task so that it fits in the slot that
- * stays open at the end.
- */
- if (initial && sched_feat(START_DEBIT))
- vruntime += sched_vslice(cfs_rq, se);
-
- /* sleeps up to a single latency don't count. */
- if (!initial) {
- unsigned long thresh = sysctl_sched_latency;
-
- /*
- * Halve their sleep time's effect, to allow
- * for a gentler effect of sleepers:
- */
- if (sched_feat(GENTLE_FAIR_SLEEPERS))
- thresh >>= 1;
-
- vruntime -= thresh;
- }
-
- /* ensure we never gain time by being placed backwards. */
- vruntime = max_vruntime(se->vruntime, vruntime);
-
- se->vruntime = vruntime;
-}
-
-static void check_enqueue_throttle(struct cfs_rq *cfs_rq);
-
-static void
-enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
-{
- /*
- * Update the normalized vruntime before updating min_vruntime
- * through callig update_curr().
- */
- if (!(flags & ENQUEUE_WAKEUP) || (flags & ENQUEUE_WAKING))
- se->vruntime += cfs_rq->min_vruntime;
-
- /*
- * Update run-time statistics of the 'current'.
- */
- update_curr(cfs_rq);
- update_cfs_load(cfs_rq, 0);
- account_entity_enqueue(cfs_rq, se);
- update_cfs_shares(cfs_rq);
-
- if (flags & ENQUEUE_WAKEUP) {
- place_entity(cfs_rq, se, 0);
- enqueue_sleeper(cfs_rq, se);
- }
-
- update_stats_enqueue(cfs_rq, se);
- check_spread(cfs_rq, se);
- if (se != cfs_rq->curr)
- __enqueue_entity(cfs_rq, se);
- se->on_rq = 1;
-
- if (cfs_rq->nr_running == 1) {
- list_add_leaf_cfs_rq(cfs_rq);
- check_enqueue_throttle(cfs_rq);
- }
-}
-
-static void __clear_buddies_last(struct sched_entity *se)
-{
- for_each_sched_entity(se) {
- struct cfs_rq *cfs_rq = cfs_rq_of(se);
- if (cfs_rq->last == se)
- cfs_rq->last = NULL;
- else
- break;
- }
-}
-
-static void __clear_buddies_next(struct sched_entity *se)
-{
- for_each_sched_entity(se) {
- struct cfs_rq *cfs_rq = cfs_rq_of(se);
- if (cfs_rq->next == se)
- cfs_rq->next = NULL;
- else
- break;
- }
-}
-
-static void __clear_buddies_skip(struct sched_entity *se)
-{
- for_each_sched_entity(se) {
- struct cfs_rq *cfs_rq = cfs_rq_of(se);
- if (cfs_rq->skip == se)
- cfs_rq->skip = NULL;
- else
- break;
- }
-}
-
-static void clear_buddies(struct cfs_rq *cfs_rq, struct sched_entity *se)
-{
- if (cfs_rq->last == se)
- __clear_buddies_last(se);
-
- if (cfs_rq->next == se)
- __clear_buddies_next(se);
-
- if (cfs_rq->skip == se)
- __clear_buddies_skip(se);
-}
-
-static void return_cfs_rq_runtime(struct cfs_rq *cfs_rq);
-
-static void
-dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
-{
- /*
- * Update run-time statistics of the 'current'.
- */
- update_curr(cfs_rq);
-
- update_stats_dequeue(cfs_rq, se);
- if (flags & DEQUEUE_SLEEP) {
-#ifdef CONFIG_SCHEDSTATS
- if (entity_is_task(se)) {
- struct task_struct *tsk = task_of(se);
-
- if (tsk->state & TASK_INTERRUPTIBLE)
- se->statistics.sleep_start = rq_of(cfs_rq)->clock;
- if (tsk->state & TASK_UNINTERRUPTIBLE)
- se->statistics.block_start = rq_of(cfs_rq)->clock;
- }
-#endif
- }
-
- clear_buddies(cfs_rq, se);
-
- if (se != cfs_rq->curr)
- __dequeue_entity(cfs_rq, se);
- se->on_rq = 0;
- update_cfs_load(cfs_rq, 0);
- account_entity_dequeue(cfs_rq, se);
-
- /*
- * Normalize the entity after updating the min_vruntime because the
- * update can refer to the ->curr item and we need to reflect this
- * movement in our normalized position.
- */
- if (!(flags & DEQUEUE_SLEEP))
- se->vruntime -= cfs_rq->min_vruntime;
-
- /* return excess runtime on last dequeue */
- return_cfs_rq_runtime(cfs_rq);
-
- update_min_vruntime(cfs_rq);
- update_cfs_shares(cfs_rq);
-}
-
-/*
- * Preempt the current task with a newly woken task if needed:
- */
-static void
-check_preempt_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr)
-{
- unsigned long ideal_runtime, delta_exec;
- struct sched_entity *se;
- s64 delta;
-
- ideal_runtime = sched_slice(cfs_rq, curr);
- delta_exec = curr->sum_exec_runtime - curr->prev_sum_exec_runtime;
- if (delta_exec > ideal_runtime) {
- resched_task(rq_of(cfs_rq)->curr);
- /*
- * The current task ran long enough, ensure it doesn't get
- * re-elected due to buddy favours.
- */
- clear_buddies(cfs_rq, curr);
- return;
- }
-
- /*
- * Ensure that a task that missed wakeup preemption by a
- * narrow margin doesn't have to wait for a full slice.
- * This also mitigates buddy induced latencies under load.
- */
- if (delta_exec < sysctl_sched_min_granularity)
- return;
-
- se = __pick_first_entity(cfs_rq);
- delta = curr->vruntime - se->vruntime;
-
- if (delta < 0)
- return;
-
- if (delta > ideal_runtime)
- resched_task(rq_of(cfs_rq)->curr);
-}
-
-static void
-set_next_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
-{
- /* 'current' is not kept within the tree. */
- if (se->on_rq) {
- /*
- * Any task has to be enqueued before it get to execute on
- * a CPU. So account for the time it spent waiting on the
- * runqueue.
- */
- update_stats_wait_end(cfs_rq, se);
- __dequeue_entity(cfs_rq, se);
- }
-
- update_stats_curr_start(cfs_rq, se);
- cfs_rq->curr = se;
-#ifdef CONFIG_SCHEDSTATS
- /*
- * Track our maximum slice length, if the CPU's load is at
- * least twice that of our own weight (i.e. dont track it
- * when there are only lesser-weight tasks around):
- */
- if (rq_of(cfs_rq)->load.weight >= 2*se->load.weight) {
- se->statistics.slice_max = max(se->statistics.slice_max,
- se->sum_exec_runtime - se->prev_sum_exec_runtime);
- }
-#endif
- se->prev_sum_exec_runtime = se->sum_exec_runtime;
-}
-
-static int
-wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se);
-
-/*
- * Pick the next process, keeping these things in mind, in this order:
- * 1) keep things fair between processes/task groups
- * 2) pick the "next" process, since someone really wants that to run
- * 3) pick the "last" process, for cache locality
- * 4) do not run the "skip" process, if something else is available
- */
-static struct sched_entity *pick_next_entity(struct cfs_rq *cfs_rq)
-{
- struct sched_entity *se = __pick_first_entity(cfs_rq);
- struct sched_entity *left = se;
-
- /*
- * Avoid running the skip buddy, if running something else can
- * be done without getting too unfair.
- */
- if (cfs_rq->skip == se) {
- struct sched_entity *second = __pick_next_entity(se);
- if (second && wakeup_preempt_entity(second, left) < 1)
- se = second;
- }
-
- /*
- * Prefer last buddy, try to return the CPU to a preempted task.
- */
- if (cfs_rq->last && wakeup_preempt_entity(cfs_rq->last, left) < 1)
- se = cfs_rq->last;
-
- /*
- * Someone really wants this to run. If it's not unfair, run it.
- */
- if (cfs_rq->next && wakeup_preempt_entity(cfs_rq->next, left) < 1)
- se = cfs_rq->next;
-
- clear_buddies(cfs_rq, se);
-
- return se;
-}
-
-static void check_cfs_rq_runtime(struct cfs_rq *cfs_rq);
-
-static void put_prev_entity(struct cfs_rq *cfs_rq, struct sched_entity *prev)
-{
- /*
- * If still on the runqueue then deactivate_task()
- * was not called and update_curr() has to be done:
- */
- if (prev->on_rq)
- update_curr(cfs_rq);
-
- /* throttle cfs_rqs exceeding runtime */
- check_cfs_rq_runtime(cfs_rq);
-
- check_spread(cfs_rq, prev);
- if (prev->on_rq) {
- update_stats_wait_start(cfs_rq, prev);
- /* Put 'current' back into the tree. */
- __enqueue_entity(cfs_rq, prev);
- }
- cfs_rq->curr = NULL;
-}
-
-static void
-entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr, int queued)
-{
- /*
- * Update run-time statistics of the 'current'.
- */
- update_curr(cfs_rq);
-
- /*
- * Update share accounting for long-running entities.
- */
- update_entity_shares_tick(cfs_rq);
-
-#ifdef CONFIG_SCHED_HRTICK
- /*
- * queued ticks are scheduled to match the slice, so don't bother
- * validating it and just reschedule.
- */
- if (queued) {
- resched_task(rq_of(cfs_rq)->curr);
- return;
- }
- /*
- * don't let the period tick interfere with the hrtick preemption
- */
- if (!sched_feat(DOUBLE_TICK) &&
- hrtimer_active(&rq_of(cfs_rq)->hrtick_timer))
- return;
-#endif
-
- if (cfs_rq->nr_running > 1)
- check_preempt_tick(cfs_rq, curr);
-}
-
-
-/**************************************************
- * CFS bandwidth control machinery
- */
-
-#ifdef CONFIG_CFS_BANDWIDTH
-
-#ifdef HAVE_JUMP_LABEL
-static struct jump_label_key __cfs_bandwidth_used;
-
-static inline bool cfs_bandwidth_used(void)
-{
- return static_branch(&__cfs_bandwidth_used);
-}
-
-void account_cfs_bandwidth_used(int enabled, int was_enabled)
-{
- /* only need to count groups transitioning between enabled/!enabled */
- if (enabled && !was_enabled)
- jump_label_inc(&__cfs_bandwidth_used);
- else if (!enabled && was_enabled)
- jump_label_dec(&__cfs_bandwidth_used);
-}
-#else /* HAVE_JUMP_LABEL */
-static bool cfs_bandwidth_used(void)
-{
- return true;
-}
-
-void account_cfs_bandwidth_used(int enabled, int was_enabled) {}
-#endif /* HAVE_JUMP_LABEL */
-
-/*
- * default period for cfs group bandwidth.
- * default: 0.1s, units: nanoseconds
- */
-static inline u64 default_cfs_period(void)
-{
- return 100000000ULL;
-}
-
-static inline u64 sched_cfs_bandwidth_slice(void)
-{
- return (u64)sysctl_sched_cfs_bandwidth_slice * NSEC_PER_USEC;
-}
-
-/*
- * Replenish runtime according to assigned quota and update expiration time.
- * We use sched_clock_cpu directly instead of rq->clock to avoid adding
- * additional synchronization around rq->lock.
- *
- * requires cfs_b->lock
- */
-void __refill_cfs_bandwidth_runtime(struct cfs_bandwidth *cfs_b)
-{
- u64 now;
-
- if (cfs_b->quota == RUNTIME_INF)
- return;
-
- now = sched_clock_cpu(smp_processor_id());
- cfs_b->runtime = cfs_b->quota;
- cfs_b->runtime_expires = now + ktime_to_ns(cfs_b->period);
-}
-
-static inline struct cfs_bandwidth *tg_cfs_bandwidth(struct task_group *tg)
-{
- return &tg->cfs_bandwidth;
-}
-
-/* returns 0 on failure to allocate runtime */
-static int assign_cfs_rq_runtime(struct cfs_rq *cfs_rq)
-{
- struct task_group *tg = cfs_rq->tg;
- struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(tg);
- u64 amount = 0, min_amount, expires;
-
- /* note: this is a positive sum as runtime_remaining <= 0 */
- min_amount = sched_cfs_bandwidth_slice() - cfs_rq->runtime_remaining;
-
- raw_spin_lock(&cfs_b->lock);
- if (cfs_b->quota == RUNTIME_INF)
- amount = min_amount;
- else {
- /*
- * If the bandwidth pool has become inactive, then at least one
- * period must have elapsed since the last consumption.
- * Refresh the global state and ensure bandwidth timer becomes
- * active.
- */
- if (!cfs_b->timer_active) {
- __refill_cfs_bandwidth_runtime(cfs_b);
- __start_cfs_bandwidth(cfs_b);
- }
-
- if (cfs_b->runtime > 0) {
- amount = min(cfs_b->runtime, min_amount);
- cfs_b->runtime -= amount;
- cfs_b->idle = 0;
- }
- }
- expires = cfs_b->runtime_expires;
- raw_spin_unlock(&cfs_b->lock);
-
- cfs_rq->runtime_remaining += amount;
- /*
- * we may have advanced our local expiration to account for allowed
- * spread between our sched_clock and the one on which runtime was
- * issued.
- */
- if ((s64)(expires - cfs_rq->runtime_expires) > 0)
- cfs_rq->runtime_expires = expires;
-
- return cfs_rq->runtime_remaining > 0;
-}
-
-/*
- * Note: This depends on the synchronization provided by sched_clock and the
- * fact that rq->clock snapshots this value.
- */
-static void expire_cfs_rq_runtime(struct cfs_rq *cfs_rq)
-{
- struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg);
- struct rq *rq = rq_of(cfs_rq);
-
- /* if the deadline is ahead of our clock, nothing to do */
- if (likely((s64)(rq->clock - cfs_rq->runtime_expires) < 0))
- return;
-
- if (cfs_rq->runtime_remaining < 0)
- return;
-
- /*
- * If the local deadline has passed we have to consider the
- * possibility that our sched_clock is 'fast' and the global deadline
- * has not truly expired.
- *
- * Fortunately we can check determine whether this the case by checking
- * whether the global deadline has advanced.
- */
-
- if ((s64)(cfs_rq->runtime_expires - cfs_b->runtime_expires) >= 0) {
- /* extend local deadline, drift is bounded above by 2 ticks */
- cfs_rq->runtime_expires += TICK_NSEC;
- } else {
- /* global deadline is ahead, expiration has passed */
- cfs_rq->runtime_remaining = 0;
- }
-}
-
-static void __account_cfs_rq_runtime(struct cfs_rq *cfs_rq,
- unsigned long delta_exec)
-{
- /* dock delta_exec before expiring quota (as it could span periods) */
- cfs_rq->runtime_remaining -= delta_exec;
- expire_cfs_rq_runtime(cfs_rq);
-
- if (likely(cfs_rq->runtime_remaining > 0))
- return;
-
- /*
- * if we're unable to extend our runtime we resched so that the active
- * hierarchy can be throttled
- */
- if (!assign_cfs_rq_runtime(cfs_rq) && likely(cfs_rq->curr))
- resched_task(rq_of(cfs_rq)->curr);
-}
-
-static __always_inline void account_cfs_rq_runtime(struct cfs_rq *cfs_rq,
- unsigned long delta_exec)
-{
- if (!cfs_bandwidth_used() || !cfs_rq->runtime_enabled)
- return;
-
- __account_cfs_rq_runtime(cfs_rq, delta_exec);
-}
-
-static inline int cfs_rq_throttled(struct cfs_rq *cfs_rq)
-{
- return cfs_bandwidth_used() && cfs_rq->throttled;
-}
-
-/* check whether cfs_rq, or any parent, is throttled */
-static inline int throttled_hierarchy(struct cfs_rq *cfs_rq)
-{
- return cfs_bandwidth_used() && cfs_rq->throttle_count;
-}
-
-/*
- * Ensure that neither of the group entities corresponding to src_cpu or
- * dest_cpu are members of a throttled hierarchy when performing group
- * load-balance operations.
- */
-static inline int throttled_lb_pair(struct task_group *tg,
- int src_cpu, int dest_cpu)
-{
- struct cfs_rq *src_cfs_rq, *dest_cfs_rq;
-
- src_cfs_rq = tg->cfs_rq[src_cpu];
- dest_cfs_rq = tg->cfs_rq[dest_cpu];
-
- return throttled_hierarchy(src_cfs_rq) ||
- throttled_hierarchy(dest_cfs_rq);
-}
-
-/* updated child weight may affect parent so we have to do this bottom up */
-static int tg_unthrottle_up(struct task_group *tg, void *data)
-{
- struct rq *rq = data;
- struct cfs_rq *cfs_rq = tg->cfs_rq[cpu_of(rq)];
-
- cfs_rq->throttle_count--;
-#ifdef CONFIG_SMP
- if (!cfs_rq->throttle_count) {
- u64 delta = rq->clock_task - cfs_rq->load_stamp;
-
- /* leaving throttled state, advance shares averaging windows */
- cfs_rq->load_stamp += delta;
- cfs_rq->load_last += delta;
-
- /* update entity weight now that we are on_rq again */
- update_cfs_shares(cfs_rq);
- }
-#endif
-
- return 0;
-}
-
-static int tg_throttle_down(struct task_group *tg, void *data)
-{
- struct rq *rq = data;
- struct cfs_rq *cfs_rq = tg->cfs_rq[cpu_of(rq)];
-
- /* group is entering throttled state, record last load */
- if (!cfs_rq->throttle_count)
- update_cfs_load(cfs_rq, 0);
- cfs_rq->throttle_count++;
-
- return 0;
-}
-
-static void throttle_cfs_rq(struct cfs_rq *cfs_rq)
-{
- struct rq *rq = rq_of(cfs_rq);
- struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg);
- struct sched_entity *se;
- long task_delta, dequeue = 1;
-
- se = cfs_rq->tg->se[cpu_of(rq_of(cfs_rq))];
-
- /* account load preceding throttle */
- rcu_read_lock();
- walk_tg_tree_from(cfs_rq->tg, tg_throttle_down, tg_nop, (void *)rq);
- rcu_read_unlock();
-
- task_delta = cfs_rq->h_nr_running;
- for_each_sched_entity(se) {
- struct cfs_rq *qcfs_rq = cfs_rq_of(se);
- /* throttled entity or throttle-on-deactivate */
- if (!se->on_rq)
- break;
-
- if (dequeue)
- dequeue_entity(qcfs_rq, se, DEQUEUE_SLEEP);
- qcfs_rq->h_nr_running -= task_delta;
-
- if (qcfs_rq->load.weight)
- dequeue = 0;
- }
-
- if (!se)
- rq->nr_running -= task_delta;
-
- cfs_rq->throttled = 1;
- cfs_rq->throttled_timestamp = rq->clock;
- raw_spin_lock(&cfs_b->lock);
- list_add_tail_rcu(&cfs_rq->throttled_list, &cfs_b->throttled_cfs_rq);
- raw_spin_unlock(&cfs_b->lock);
-}
-
-void unthrottle_cfs_rq(struct cfs_rq *cfs_rq)
-{
- struct rq *rq = rq_of(cfs_rq);
- struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg);
- struct sched_entity *se;
- int enqueue = 1;
- long task_delta;
-
- se = cfs_rq->tg->se[cpu_of(rq_of(cfs_rq))];
-
- cfs_rq->throttled = 0;
- raw_spin_lock(&cfs_b->lock);
- cfs_b->throttled_time += rq->clock - cfs_rq->throttled_timestamp;
- list_del_rcu(&cfs_rq->throttled_list);
- raw_spin_unlock(&cfs_b->lock);
- cfs_rq->throttled_timestamp = 0;
-
- update_rq_clock(rq);
- /* update hierarchical throttle state */
- walk_tg_tree_from(cfs_rq->tg, tg_nop, tg_unthrottle_up, (void *)rq);
-
- if (!cfs_rq->load.weight)
- return;
-
- task_delta = cfs_rq->h_nr_running;
- for_each_sched_entity(se) {
- if (se->on_rq)
- enqueue = 0;
-
- cfs_rq = cfs_rq_of(se);
- if (enqueue)
- enqueue_entity(cfs_rq, se, ENQUEUE_WAKEUP);
- cfs_rq->h_nr_running += task_delta;
-
- if (cfs_rq_throttled(cfs_rq))
- break;
- }
-
- if (!se)
- rq->nr_running += task_delta;
-
- /* determine whether we need to wake up potentially idle cpu */
- if (rq->curr == rq->idle && rq->cfs.nr_running)
- resched_task(rq->curr);
-}
-
-static u64 distribute_cfs_runtime(struct cfs_bandwidth *cfs_b,
- u64 remaining, u64 expires)
-{
- struct cfs_rq *cfs_rq;
- u64 runtime = remaining;
-
- rcu_read_lock();
- list_for_each_entry_rcu(cfs_rq, &cfs_b->throttled_cfs_rq,
- throttled_list) {
- struct rq *rq = rq_of(cfs_rq);
-
- raw_spin_lock(&rq->lock);
- if (!cfs_rq_throttled(cfs_rq))
- goto next;
-
- runtime = -cfs_rq->runtime_remaining + 1;
- if (runtime > remaining)
- runtime = remaining;
- remaining -= runtime;
-
- cfs_rq->runtime_remaining += runtime;
- cfs_rq->runtime_expires = expires;
-
- /* we check whether we're throttled above */
- if (cfs_rq->runtime_remaining > 0)
- unthrottle_cfs_rq(cfs_rq);
-
-next:
- raw_spin_unlock(&rq->lock);
-
- if (!remaining)
- break;
- }
- rcu_read_unlock();
-
- return remaining;
-}
-
-/*
- * Responsible for refilling a task_group's bandwidth and unthrottling its
- * cfs_rqs as appropriate. If there has been no activity within the last
- * period the timer is deactivated until scheduling resumes; cfs_b->idle is
- * used to track this state.
- */
-static int do_sched_cfs_period_timer(struct cfs_bandwidth *cfs_b, int overrun)
-{
- u64 runtime, runtime_expires;
- int idle = 1, throttled;
-
- raw_spin_lock(&cfs_b->lock);
- /* no need to continue the timer with no bandwidth constraint */
- if (cfs_b->quota == RUNTIME_INF)
- goto out_unlock;
-
- throttled = !list_empty(&cfs_b->throttled_cfs_rq);
- /* idle depends on !throttled (for the case of a large deficit) */
- idle = cfs_b->idle && !throttled;
- cfs_b->nr_periods += overrun;
-
- /* if we're going inactive then everything else can be deferred */
- if (idle)
- goto out_unlock;
-
- __refill_cfs_bandwidth_runtime(cfs_b);
-
- if (!throttled) {
- /* mark as potentially idle for the upcoming period */
- cfs_b->idle = 1;
- goto out_unlock;
- }
-
- /* account preceding periods in which throttling occurred */
- cfs_b->nr_throttled += overrun;
-
- /*
- * There are throttled entities so we must first use the new bandwidth
- * to unthrottle them before making it generally available. This
- * ensures that all existing debts will be paid before a new cfs_rq is
- * allowed to run.
- */
- runtime = cfs_b->runtime;
- runtime_expires = cfs_b->runtime_expires;
- cfs_b->runtime = 0;
-
- /*
- * This check is repeated as we are holding onto the new bandwidth
- * while we unthrottle. This can potentially race with an unthrottled
- * group trying to acquire new bandwidth from the global pool.
- */
- while (throttled && runtime > 0) {
- raw_spin_unlock(&cfs_b->lock);
- /* we can't nest cfs_b->lock while distributing bandwidth */
- runtime = distribute_cfs_runtime(cfs_b, runtime,
- runtime_expires);
- raw_spin_lock(&cfs_b->lock);
-
- throttled = !list_empty(&cfs_b->throttled_cfs_rq);
- }
-
- /* return (any) remaining runtime */
- cfs_b->runtime = runtime;
- /*
- * While we are ensured activity in the period following an
- * unthrottle, this also covers the case in which the new bandwidth is
- * insufficient to cover the existing bandwidth deficit. (Forcing the
- * timer to remain active while there are any throttled entities.)
- */
- cfs_b->idle = 0;
-out_unlock:
- if (idle)
- cfs_b->timer_active = 0;
- raw_spin_unlock(&cfs_b->lock);
-
- return idle;
-}
-
-/* a cfs_rq won't donate quota below this amount */
-static const u64 min_cfs_rq_runtime = 1 * NSEC_PER_MSEC;
-/* minimum remaining period time to redistribute slack quota */
-static const u64 min_bandwidth_expiration = 2 * NSEC_PER_MSEC;
-/* how long we wait to gather additional slack before distributing */
-static const u64 cfs_bandwidth_slack_period = 5 * NSEC_PER_MSEC;
-
-/* are we near the end of the current quota period? */
-static int runtime_refresh_within(struct cfs_bandwidth *cfs_b, u64 min_expire)
-{
- struct hrtimer *refresh_timer = &cfs_b->period_timer;
- u64 remaining;
-
- /* if the call-back is running a quota refresh is already occurring */
- if (hrtimer_callback_running(refresh_timer))
- return 1;
-
- /* is a quota refresh about to occur? */
- remaining = ktime_to_ns(hrtimer_expires_remaining(refresh_timer));
- if (remaining < min_expire)
- return 1;
-
- return 0;
-}
-
-static void start_cfs_slack_bandwidth(struct cfs_bandwidth *cfs_b)
-{
- u64 min_left = cfs_bandwidth_slack_period + min_bandwidth_expiration;
-
- /* if there's a quota refresh soon don't bother with slack */
- if (runtime_refresh_within(cfs_b, min_left))
- return;
-
- start_bandwidth_timer(&cfs_b->slack_timer,
- ns_to_ktime(cfs_bandwidth_slack_period));
-}
-
-/* we know any runtime found here is valid as update_curr() precedes return */
-static void __return_cfs_rq_runtime(struct cfs_rq *cfs_rq)
-{
- struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg);
- s64 slack_runtime = cfs_rq->runtime_remaining - min_cfs_rq_runtime;
-
- if (slack_runtime <= 0)
- return;
-
- raw_spin_lock(&cfs_b->lock);
- if (cfs_b->quota != RUNTIME_INF &&
- cfs_rq->runtime_expires == cfs_b->runtime_expires) {
- cfs_b->runtime += slack_runtime;
-
- /* we are under rq->lock, defer unthrottling using a timer */
- if (cfs_b->runtime > sched_cfs_bandwidth_slice() &&
- !list_empty(&cfs_b->throttled_cfs_rq))
- start_cfs_slack_bandwidth(cfs_b);
- }
- raw_spin_unlock(&cfs_b->lock);
-
- /* even if it's not valid for return we don't want to try again */
- cfs_rq->runtime_remaining -= slack_runtime;
-}
-
-static __always_inline void return_cfs_rq_runtime(struct cfs_rq *cfs_rq)
-{
- if (!cfs_bandwidth_used())
- return;
-
- if (!cfs_rq->runtime_enabled || cfs_rq->nr_running)
- return;
-
- __return_cfs_rq_runtime(cfs_rq);
-}
-
-/*
- * This is done with a timer (instead of inline with bandwidth return) since
- * it's necessary to juggle rq->locks to unthrottle their respective cfs_rqs.
- */
-static void do_sched_cfs_slack_timer(struct cfs_bandwidth *cfs_b)
-{
- u64 runtime = 0, slice = sched_cfs_bandwidth_slice();
- u64 expires;
-
- /* confirm we're still not at a refresh boundary */
- if (runtime_refresh_within(cfs_b, min_bandwidth_expiration))
- return;
-
- raw_spin_lock(&cfs_b->lock);
- if (cfs_b->quota != RUNTIME_INF && cfs_b->runtime > slice) {
- runtime = cfs_b->runtime;
- cfs_b->runtime = 0;
- }
- expires = cfs_b->runtime_expires;
- raw_spin_unlock(&cfs_b->lock);
-
- if (!runtime)
- return;
-
- runtime = distribute_cfs_runtime(cfs_b, runtime, expires);
-
- raw_spin_lock(&cfs_b->lock);
- if (expires == cfs_b->runtime_expires)
- cfs_b->runtime = runtime;
- raw_spin_unlock(&cfs_b->lock);
-}
-
-/*
- * When a group wakes up we want to make sure that its quota is not already
- * expired/exceeded, otherwise it may be allowed to steal additional ticks of
- * runtime as update_curr() throttling can not not trigger until it's on-rq.
- */
-static void check_enqueue_throttle(struct cfs_rq *cfs_rq)
-{
- if (!cfs_bandwidth_used())
- return;
-
- /* an active group must be handled by the update_curr()->put() path */
- if (!cfs_rq->runtime_enabled || cfs_rq->curr)
- return;
-
- /* ensure the group is not already throttled */
- if (cfs_rq_throttled(cfs_rq))
- return;
-
- /* update runtime allocation */
- account_cfs_rq_runtime(cfs_rq, 0);
- if (cfs_rq->runtime_remaining <= 0)
- throttle_cfs_rq(cfs_rq);
-}
-
-/* conditionally throttle active cfs_rq's from put_prev_entity() */
-static void check_cfs_rq_runtime(struct cfs_rq *cfs_rq)
-{
- if (!cfs_bandwidth_used())
- return;
-
- if (likely(!cfs_rq->runtime_enabled || cfs_rq->runtime_remaining > 0))
- return;
-
- /*
- * it's possible for a throttled entity to be forced into a running
- * state (e.g. set_curr_task), in this case we're finished.
- */
- if (cfs_rq_throttled(cfs_rq))
- return;
-
- throttle_cfs_rq(cfs_rq);
-}
-
-static inline u64 default_cfs_period(void);
-static int do_sched_cfs_period_timer(struct cfs_bandwidth *cfs_b, int overrun);
-static void do_sched_cfs_slack_timer(struct cfs_bandwidth *cfs_b);
-
-static enum hrtimer_restart sched_cfs_slack_timer(struct hrtimer *timer)
-{
- struct cfs_bandwidth *cfs_b =
- container_of(timer, struct cfs_bandwidth, slack_timer);
- do_sched_cfs_slack_timer(cfs_b);
-
- return HRTIMER_NORESTART;
-}
-
-static enum hrtimer_restart sched_cfs_period_timer(struct hrtimer *timer)
-{
- struct cfs_bandwidth *cfs_b =
- container_of(timer, struct cfs_bandwidth, period_timer);
- ktime_t now;
- int overrun;
- int idle = 0;
-
- for (;;) {
- now = hrtimer_cb_get_time(timer);
- overrun = hrtimer_forward(timer, now, cfs_b->period);
-
- if (!overrun)
- break;
-
- idle = do_sched_cfs_period_timer(cfs_b, overrun);
- }
-
- return idle ? HRTIMER_NORESTART : HRTIMER_RESTART;
-}
-
-void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b)
-{
- raw_spin_lock_init(&cfs_b->lock);
- cfs_b->runtime = 0;
- cfs_b->quota = RUNTIME_INF;
- cfs_b->period = ns_to_ktime(default_cfs_period());
-
- INIT_LIST_HEAD(&cfs_b->throttled_cfs_rq);
- hrtimer_init(&cfs_b->period_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
- cfs_b->period_timer.function = sched_cfs_period_timer;
- hrtimer_init(&cfs_b->slack_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
- cfs_b->slack_timer.function = sched_cfs_slack_timer;
-}
-
-static void init_cfs_rq_runtime(struct cfs_rq *cfs_rq)
-{
- cfs_rq->runtime_enabled = 0;
- INIT_LIST_HEAD(&cfs_rq->throttled_list);
-}
-
-/* requires cfs_b->lock, may release to reprogram timer */
-void __start_cfs_bandwidth(struct cfs_bandwidth *cfs_b)
-{
- /*
- * The timer may be active because we're trying to set a new bandwidth
- * period or because we're racing with the tear-down path
- * (timer_active==0 becomes visible before the hrtimer call-back
- * terminates). In either case we ensure that it's re-programmed
- */
- while (unlikely(hrtimer_active(&cfs_b->period_timer))) {
- raw_spin_unlock(&cfs_b->lock);
- /* ensure cfs_b->lock is available while we wait */
- hrtimer_cancel(&cfs_b->period_timer);
-
- raw_spin_lock(&cfs_b->lock);
- /* if someone else restarted the timer then we're done */
- if (cfs_b->timer_active)
- return;
- }
-
- cfs_b->timer_active = 1;
- start_bandwidth_timer(&cfs_b->period_timer, cfs_b->period);
-}
-
-static void destroy_cfs_bandwidth(struct cfs_bandwidth *cfs_b)
-{
- hrtimer_cancel(&cfs_b->period_timer);
- hrtimer_cancel(&cfs_b->slack_timer);
-}
-
-void unthrottle_offline_cfs_rqs(struct rq *rq)
-{
- struct cfs_rq *cfs_rq;
-
- for_each_leaf_cfs_rq(rq, cfs_rq) {
- struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg);
-
- if (!cfs_rq->runtime_enabled)
- continue;
-
- /*
- * clock_task is not advancing so we just need to make sure
- * there's some valid quota amount
- */
- cfs_rq->runtime_remaining = cfs_b->quota;
- if (cfs_rq_throttled(cfs_rq))
- unthrottle_cfs_rq(cfs_rq);
- }
-}
-
-#else /* CONFIG_CFS_BANDWIDTH */
-static void account_cfs_rq_runtime(struct cfs_rq *cfs_rq,
- unsigned long delta_exec) {}
-static void check_cfs_rq_runtime(struct cfs_rq *cfs_rq) {}
-static void check_enqueue_throttle(struct cfs_rq *cfs_rq) {}
-static void return_cfs_rq_runtime(struct cfs_rq *cfs_rq) {}
-
-static inline int cfs_rq_throttled(struct cfs_rq *cfs_rq)
-{
- return 0;
-}
-
-static inline int throttled_hierarchy(struct cfs_rq *cfs_rq)
-{
- return 0;
-}
-
-static inline int throttled_lb_pair(struct task_group *tg,
- int src_cpu, int dest_cpu)
-{
- return 0;
-}
-
-void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b) {}
-
-#ifdef CONFIG_FAIR_GROUP_SCHED
-static void init_cfs_rq_runtime(struct cfs_rq *cfs_rq) {}
-#endif
-
-static inline struct cfs_bandwidth *tg_cfs_bandwidth(struct task_group *tg)
-{
- return NULL;
-}
-static inline void destroy_cfs_bandwidth(struct cfs_bandwidth *cfs_b) {}
-void unthrottle_offline_cfs_rqs(struct rq *rq) {}
-
-#endif /* CONFIG_CFS_BANDWIDTH */
-
-/**************************************************
- * CFS operations on tasks:
- */
-
-#ifdef CONFIG_SCHED_HRTICK
-static void hrtick_start_fair(struct rq *rq, struct task_struct *p)
-{
- struct sched_entity *se = &p->se;
- struct cfs_rq *cfs_rq = cfs_rq_of(se);
-
- WARN_ON(task_rq(p) != rq);
-
- if (hrtick_enabled(rq) && cfs_rq->nr_running > 1) {
- u64 slice = sched_slice(cfs_rq, se);
- u64 ran = se->sum_exec_runtime - se->prev_sum_exec_runtime;
- s64 delta = slice - ran;
-
- if (delta < 0) {
- if (rq->curr == p)
- resched_task(p);
- return;
- }
-
- /*
- * Don't schedule slices shorter than 10000ns, that just
- * doesn't make sense. Rely on vruntime for fairness.
- */
- if (rq->curr != p)
- delta = max_t(s64, 10000LL, delta);
-
- hrtick_start(rq, delta);
- }
-}
-
-/*
- * called from enqueue/dequeue and updates the hrtick when the
- * current task is from our class and nr_running is low enough
- * to matter.
- */
-static void hrtick_update(struct rq *rq)
-{
- struct task_struct *curr = rq->curr;
-
- if (curr->sched_class != &fair_sched_class)
- return;
-
- if (cfs_rq_of(&curr->se)->nr_running < sched_nr_latency)
- hrtick_start_fair(rq, curr);
-}
-#else /* !CONFIG_SCHED_HRTICK */
-static inline void
-hrtick_start_fair(struct rq *rq, struct task_struct *p)
-{
-}
-
-static inline void hrtick_update(struct rq *rq)
-{
-}
-#endif
-
-/*
- * The enqueue_task method is called before nr_running is
- * increased. Here we update the fair scheduling stats and
- * then put the task into the rbtree:
- */
-static void
-enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)
-{
- struct cfs_rq *cfs_rq;
- struct sched_entity *se = &p->se;
-
- for_each_sched_entity(se) {
- if (se->on_rq)
- break;
- cfs_rq = cfs_rq_of(se);
- enqueue_entity(cfs_rq, se, flags);
-
- /*
- * end evaluation on encountering a throttled cfs_rq
- *
- * note: in the case of encountering a throttled cfs_rq we will
- * post the final h_nr_running increment below.
- */
- if (cfs_rq_throttled(cfs_rq))
- break;
- cfs_rq->h_nr_running++;
-
- flags = ENQUEUE_WAKEUP;
- }
-
- for_each_sched_entity(se) {
- cfs_rq = cfs_rq_of(se);
- cfs_rq->h_nr_running++;
-
- if (cfs_rq_throttled(cfs_rq))
- break;
-
- update_cfs_load(cfs_rq, 0);
- update_cfs_shares(cfs_rq);
- }
-
- if (!se)
- inc_nr_running(rq);
- hrtick_update(rq);
-}
-
-static void set_next_buddy(struct sched_entity *se);
-
-/*
- * The dequeue_task method is called before nr_running is
- * decreased. We remove the task from the rbtree and
- * update the fair scheduling stats:
- */
-static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags)
-{
- struct cfs_rq *cfs_rq;
- struct sched_entity *se = &p->se;
- int task_sleep = flags & DEQUEUE_SLEEP;
-
- for_each_sched_entity(se) {
- cfs_rq = cfs_rq_of(se);
- dequeue_entity(cfs_rq, se, flags);
-
- /*
- * end evaluation on encountering a throttled cfs_rq
- *
- * note: in the case of encountering a throttled cfs_rq we will
- * post the final h_nr_running decrement below.
- */
- if (cfs_rq_throttled(cfs_rq))
- break;
- cfs_rq->h_nr_running--;
-
- /* Don't dequeue parent if it has other entities besides us */
- if (cfs_rq->load.weight) {
- /*
- * Bias pick_next to pick a task from this cfs_rq, as
- * p is sleeping when it is within its sched_slice.
- */
- if (task_sleep && parent_entity(se))
- set_next_buddy(parent_entity(se));
-
- /* avoid re-evaluating load for this entity */
- se = parent_entity(se);
- break;
- }
- flags |= DEQUEUE_SLEEP;
- }
-
- for_each_sched_entity(se) {
- cfs_rq = cfs_rq_of(se);
- cfs_rq->h_nr_running--;
-
- if (cfs_rq_throttled(cfs_rq))
- break;
-
- update_cfs_load(cfs_rq, 0);
- update_cfs_shares(cfs_rq);
- }
-
- if (!se)
- dec_nr_running(rq);
- hrtick_update(rq);
-}
-
-#ifdef CONFIG_SMP
-/* Used instead of source_load when we know the type == 0 */
-static unsigned long weighted_cpuload(const int cpu)
-{
- return cpu_rq(cpu)->load.weight;
-}
-
-/*
- * Return a low guess at the load of a migration-source cpu weighted
- * according to the scheduling class and "nice" value.
- *
- * We want to under-estimate the load of migration sources, to
- * balance conservatively.
- */
-static unsigned long source_load(int cpu, int type)
-{
- struct rq *rq = cpu_rq(cpu);
- unsigned long total = weighted_cpuload(cpu);
-
- if (type == 0 || !sched_feat(LB_BIAS))
- return total;
-
- return min(rq->cpu_load[type-1], total);
-}
-
-/*
- * Return a high guess at the load of a migration-target cpu weighted
- * according to the scheduling class and "nice" value.
- */
-static unsigned long target_load(int cpu, int type)
-{
- struct rq *rq = cpu_rq(cpu);
- unsigned long total = weighted_cpuload(cpu);
-
- if (type == 0 || !sched_feat(LB_BIAS))
- return total;
-
- return max(rq->cpu_load[type-1], total);
-}
-
-static unsigned long power_of(int cpu)
-{
- return cpu_rq(cpu)->cpu_power;
-}
-
-static unsigned long cpu_avg_load_per_task(int cpu)
-{
- struct rq *rq = cpu_rq(cpu);
- unsigned long nr_running = ACCESS_ONCE(rq->nr_running);
-
- if (nr_running)
- return rq->load.weight / nr_running;
-
- return 0;
-}
-
-
-static void task_waking_fair(struct task_struct *p)
-{
- struct sched_entity *se = &p->se;
- struct cfs_rq *cfs_rq = cfs_rq_of(se);
- u64 min_vruntime;
-
-#ifndef CONFIG_64BIT
- u64 min_vruntime_copy;
-
- do {
- min_vruntime_copy = cfs_rq->min_vruntime_copy;
- smp_rmb();
- min_vruntime = cfs_rq->min_vruntime;
- } while (min_vruntime != min_vruntime_copy);
-#else
- min_vruntime = cfs_rq->min_vruntime;
-#endif
-
- se->vruntime -= min_vruntime;
-}
-
-#ifdef CONFIG_FAIR_GROUP_SCHED
-/*
- * effective_load() calculates the load change as seen from the root_task_group
- *
- * Adding load to a group doesn't make a group heavier, but can cause movement
- * of group shares between cpus. Assuming the shares were perfectly aligned one
- * can calculate the shift in shares.
- *
- * Calculate the effective load difference if @wl is added (subtracted) to @tg
- * on this @cpu and results in a total addition (subtraction) of @wg to the
- * total group weight.
- *
- * Given a runqueue weight distribution (rw_i) we can compute a shares
- * distribution (s_i) using:
- *
- * s_i = rw_i / \Sum rw_j (1)
- *
- * Suppose we have 4 CPUs and our @tg is a direct child of the root group and
- * has 7 equal weight tasks, distributed as below (rw_i), with the resulting
- * shares distribution (s_i):
- *
- * rw_i = { 2, 4, 1, 0 }
- * s_i = { 2/7, 4/7, 1/7, 0 }
- *
- * As per wake_affine() we're interested in the load of two CPUs (the CPU the
- * task used to run on and the CPU the waker is running on), we need to
- * compute the effect of waking a task on either CPU and, in case of a sync
- * wakeup, compute the effect of the current task going to sleep.
- *
- * So for a change of @wl to the local @cpu with an overall group weight change
- * of @wl we can compute the new shares distribution (s'_i) using:
- *
- * s'_i = (rw_i + @wl) / (@wg + \Sum rw_j) (2)
- *
- * Suppose we're interested in CPUs 0 and 1, and want to compute the load
- * differences in waking a task to CPU 0. The additional task changes the
- * weight and shares distributions like:
- *
- * rw'_i = { 3, 4, 1, 0 }
- * s'_i = { 3/8, 4/8, 1/8, 0 }
- *
- * We can then compute the difference in effective weight by using:
- *
- * dw_i = S * (s'_i - s_i) (3)
- *
- * Where 'S' is the group weight as seen by its parent.
- *
- * Therefore the effective change in loads on CPU 0 would be 5/56 (3/8 - 2/7)
- * times the weight of the group. The effect on CPU 1 would be -4/56 (4/8 -
- * 4/7) times the weight of the group.
- */
-static long effective_load(struct task_group *tg, int cpu, long wl, long wg)
-{
- struct sched_entity *se = tg->se[cpu];
-
- if (!tg->parent) /* the trivial, non-cgroup case */
- return wl;
-
- for_each_sched_entity(se) {
- long w, W;
-
- tg = se->my_q->tg;
-
- /*
- * W = @wg + \Sum rw_j
- */
- W = wg + calc_tg_weight(tg, se->my_q);
-
- /*
- * w = rw_i + @wl
- */
- w = se->my_q->load.weight + wl;
-
- /*
- * wl = S * s'_i; see (2)
- */
- if (W > 0 && w < W)
- wl = (w * tg->shares) / W;
- else
- wl = tg->shares;
-
- /*
- * Per the above, wl is the new se->load.weight value; since
- * those are clipped to [MIN_SHARES, ...) do so now. See
- * calc_cfs_shares().
- */
- if (wl < MIN_SHARES)
- wl = MIN_SHARES;
-
- /*
- * wl = dw_i = S * (s'_i - s_i); see (3)
- */
- wl -= se->load.weight;
-
- /*
- * Recursively apply this logic to all parent groups to compute
- * the final effective load change on the root group. Since
- * only the @tg group gets extra weight, all parent groups can
- * only redistribute existing shares. @wl is the shift in shares
- * resulting from this level per the above.
- */
- wg = 0;
- }
-
- return wl;
-}
-#else
-
-static inline unsigned long effective_load(struct task_group *tg, int cpu,
- unsigned long wl, unsigned long wg)
-{
- return wl;
-}
-
-#endif
-
-static int wake_affine(struct sched_domain *sd, struct task_struct *p, int sync)
-{
- s64 this_load, load;
- int idx, this_cpu, prev_cpu;
- unsigned long tl_per_task;
- struct task_group *tg;
- unsigned long weight;
- int balanced;
-
- idx = sd->wake_idx;
- this_cpu = smp_processor_id();
- prev_cpu = task_cpu(p);
- load = source_load(prev_cpu, idx);
- this_load = target_load(this_cpu, idx);
-
- /*
- * If sync wakeup then subtract the (maximum possible)
- * effect of the currently running task from the load
- * of the current CPU:
- */
- if (sync) {
- tg = task_group(current);
- weight = current->se.load.weight;
-
- this_load += effective_load(tg, this_cpu, -weight, -weight);
- load += effective_load(tg, prev_cpu, 0, -weight);
- }
-
- tg = task_group(p);
- weight = p->se.load.weight;
-
- /*
- * In low-load situations, where prev_cpu is idle and this_cpu is idle
- * due to the sync cause above having dropped this_load to 0, we'll
- * always have an imbalance, but there's really nothing you can do
- * about that, so that's good too.
- *
- * Otherwise check if either cpus are near enough in load to allow this
- * task to be woken on this_cpu.
- */
- if (this_load > 0) {
- s64 this_eff_load, prev_eff_load;
-
- this_eff_load = 100;
- this_eff_load *= power_of(prev_cpu);
- this_eff_load *= this_load +
- effective_load(tg, this_cpu, weight, weight);
-
- prev_eff_load = 100 + (sd->imbalance_pct - 100) / 2;
- prev_eff_load *= power_of(this_cpu);
- prev_eff_load *= load + effective_load(tg, prev_cpu, 0, weight);
-
- balanced = this_eff_load <= prev_eff_load;
- } else
- balanced = true;
-
- /*
- * If the currently running task will sleep within
- * a reasonable amount of time then attract this newly
- * woken task:
- */
- if (sync && balanced)
- return 1;
-
- schedstat_inc(p, se.statistics.nr_wakeups_affine_attempts);
- tl_per_task = cpu_avg_load_per_task(this_cpu);
-
- if (balanced ||
- (this_load <= load &&
- this_load + target_load(prev_cpu, idx) <= tl_per_task)) {
- /*
- * This domain has SD_WAKE_AFFINE and
- * p is cache cold in this domain, and
- * there is no bad imbalance.
- */
- schedstat_inc(sd, ttwu_move_affine);
- schedstat_inc(p, se.statistics.nr_wakeups_affine);
-
- return 1;
- }
- return 0;
-}
-
-/*
- * find_idlest_group finds and returns the least busy CPU group within the
- * domain.
- */
-static struct sched_group *
-find_idlest_group(struct sched_domain *sd, struct task_struct *p,
- int this_cpu, int load_idx)
-{
- struct sched_group *idlest = NULL, *group = sd->groups;
- unsigned long min_load = ULONG_MAX, this_load = 0;
- int imbalance = 100 + (sd->imbalance_pct-100)/2;
-
- do {
- unsigned long load, avg_load;
- int local_group;
- int i;
-
- /* Skip over this group if it has no CPUs allowed */
- if (!cpumask_intersects(sched_group_cpus(group),
- tsk_cpus_allowed(p)))
- continue;
-
- local_group = cpumask_test_cpu(this_cpu,
- sched_group_cpus(group));
-
- /* Tally up the load of all CPUs in the group */
- avg_load = 0;
-
- for_each_cpu(i, sched_group_cpus(group)) {
- /* Bias balancing toward cpus of our domain */
- if (local_group)
- load = source_load(i, load_idx);
- else
- load = target_load(i, load_idx);
-
- avg_load += load;
- }
-
- /* Adjust by relative CPU power of the group */
- avg_load = (avg_load * SCHED_POWER_SCALE) / group->sgp->power;
-
- if (local_group) {
- this_load = avg_load;
- } else if (avg_load < min_load) {
- min_load = avg_load;
- idlest = group;
- }
- } while (group = group->next, group != sd->groups);
-
- if (!idlest || 100*this_load < imbalance*min_load)
- return NULL;
- return idlest;
-}
-
-/*
- * find_idlest_cpu - find the idlest cpu among the cpus in group.
- */
-static int
-find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu)
-{
- unsigned long load, min_load = ULONG_MAX;
- int idlest = -1;
- int i;
-
- /* Traverse only the allowed CPUs */
- for_each_cpu_and(i, sched_group_cpus(group), tsk_cpus_allowed(p)) {
- load = weighted_cpuload(i);
-
- if (load < min_load || (load == min_load && i == this_cpu)) {
- min_load = load;
- idlest = i;
- }
- }
-
- return idlest;
-}
-
-/*
- * Try and locate an idle CPU in the sched_domain.
- */
-static int select_idle_sibling(struct task_struct *p, int target)
-{
- int cpu = smp_processor_id();
- int prev_cpu = task_cpu(p);
- struct sched_domain *sd;
- struct sched_group *sg;
- int i, smt = 0;
-
- /*
- * If the task is going to be woken-up on this cpu and if it is
- * already idle, then it is the right target.
- */
- if (target == cpu && idle_cpu(cpu))
- return cpu;
-
- /*
- * If the task is going to be woken-up on the cpu where it previously
- * ran and if it is currently idle, then it the right target.
- */
- if (target == prev_cpu && idle_cpu(prev_cpu))
- return prev_cpu;
-
- /*
- * Otherwise, iterate the domains and find an elegible idle cpu.
- */
- rcu_read_lock();
-again:
- for_each_domain(target, sd) {
- if (!smt && (sd->flags & SD_SHARE_CPUPOWER))
- continue;
-
- if (!(sd->flags & SD_SHARE_PKG_RESOURCES)) {
- if (!smt) {
- smt = 1;
- goto again;
- }
- break;
- }
-
- sg = sd->groups;
- do {
- if (!cpumask_intersects(sched_group_cpus(sg),
- tsk_cpus_allowed(p)))
- goto next;
-
- for_each_cpu(i, sched_group_cpus(sg)) {
- if (!idle_cpu(i))
- goto next;
- }
-
- target = cpumask_first_and(sched_group_cpus(sg),
- tsk_cpus_allowed(p));
- goto done;
-next:
- sg = sg->next;
- } while (sg != sd->groups);
- }
-done:
- rcu_read_unlock();
-
- return target;
-}
-
-/*
- * sched_balance_self: balance the current task (running on cpu) in domains
- * that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and
- * SD_BALANCE_EXEC.
- *
- * Balance, ie. select the least loaded group.
- *
- * Returns the target CPU number, or the same CPU if no balancing is needed.
- *
- * preempt must be disabled.
- */
-static int
-select_task_rq_fair(struct task_struct *p, int sd_flag, int wake_flags)
-{
- struct sched_domain *tmp, *affine_sd = NULL, *sd = NULL;
- int cpu = smp_processor_id();
- int prev_cpu = task_cpu(p);
- int new_cpu = cpu;
- int want_affine = 0;
- int want_sd = 1;
- int sync = wake_flags & WF_SYNC;
-
- if (sd_flag & SD_BALANCE_WAKE) {
- if (cpumask_test_cpu(cpu, tsk_cpus_allowed(p)))
- want_affine = 1;
- new_cpu = prev_cpu;
- }
-
- rcu_read_lock();
- for_each_domain(cpu, tmp) {
- if (!(tmp->flags & SD_LOAD_BALANCE))
- continue;
-
- /*
- * If power savings logic is enabled for a domain, see if we
- * are not overloaded, if so, don't balance wider.
- */
- if (tmp->flags & (SD_POWERSAVINGS_BALANCE|SD_PREFER_LOCAL)) {
- unsigned long power = 0;
- unsigned long nr_running = 0;
- unsigned long capacity;
- int i;
-
- for_each_cpu(i, sched_domain_span(tmp)) {
- power += power_of(i);
- nr_running += cpu_rq(i)->cfs.nr_running;
- }
-
- capacity = DIV_ROUND_CLOSEST(power, SCHED_POWER_SCALE);
-
- if (tmp->flags & SD_POWERSAVINGS_BALANCE)
- nr_running /= 2;
-
- if (nr_running < capacity)
- want_sd = 0;
- }
-
- /*
- * If both cpu and prev_cpu are part of this domain,
- * cpu is a valid SD_WAKE_AFFINE target.
- */
- if (want_affine && (tmp->flags & SD_WAKE_AFFINE) &&
- cpumask_test_cpu(prev_cpu, sched_domain_span(tmp))) {
- affine_sd = tmp;
- want_affine = 0;
- }
-
- if (!want_sd && !want_affine)
- break;
-
- if (!(tmp->flags & sd_flag))
- continue;
-
- if (want_sd)
- sd = tmp;
- }
-
- if (affine_sd) {
- if (cpu == prev_cpu || wake_affine(affine_sd, p, sync))
- prev_cpu = cpu;
-
- new_cpu = select_idle_sibling(p, prev_cpu);
- goto unlock;
- }
-
- while (sd) {
- int load_idx = sd->forkexec_idx;
- struct sched_group *group;
- int weight;
-
- if (!(sd->flags & sd_flag)) {
- sd = sd->child;
- continue;
- }
-
- if (sd_flag & SD_BALANCE_WAKE)
- load_idx = sd->wake_idx;
-
- group = find_idlest_group(sd, p, cpu, load_idx);
- if (!group) {
- sd = sd->child;
- continue;
- }
-
- new_cpu = find_idlest_cpu(group, p, cpu);
- if (new_cpu == -1 || new_cpu == cpu) {
- /* Now try balancing at a lower domain level of cpu */
- sd = sd->child;
- continue;
- }
-
- /* Now try balancing at a lower domain level of new_cpu */
- cpu = new_cpu;
- weight = sd->span_weight;
- sd = NULL;
- for_each_domain(cpu, tmp) {
- if (weight <= tmp->span_weight)
- break;
- if (tmp->flags & sd_flag)
- sd = tmp;
- }
- /* while loop will break here if sd == NULL */
- }
-unlock:
- rcu_read_unlock();
-
- return new_cpu;
-}
-#endif /* CONFIG_SMP */
-
-static unsigned long
-wakeup_gran(struct sched_entity *curr, struct sched_entity *se)
-{
- unsigned long gran = sysctl_sched_wakeup_granularity;
-
- /*
- * Since its curr running now, convert the gran from real-time
- * to virtual-time in his units.
- *
- * By using 'se' instead of 'curr' we penalize light tasks, so
- * they get preempted easier. That is, if 'se' < 'curr' then
- * the resulting gran will be larger, therefore penalizing the
- * lighter, if otoh 'se' > 'curr' then the resulting gran will
- * be smaller, again penalizing the lighter task.
- *
- * This is especially important for buddies when the leftmost
- * task is higher priority than the buddy.
- */
- return calc_delta_fair(gran, se);
-}
-
-/*
- * Should 'se' preempt 'curr'.
- *
- * |s1
- * |s2
- * |s3
- * g
- * |<--->|c
- *
- * w(c, s1) = -1
- * w(c, s2) = 0
- * w(c, s3) = 1
- *
- */
-static int
-wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se)
-{
- s64 gran, vdiff = curr->vruntime - se->vruntime;
-
- if (vdiff <= 0)
- return -1;
-
- gran = wakeup_gran(curr, se);
- if (vdiff > gran)
- return 1;
-
- return 0;
-}
-
-static void set_last_buddy(struct sched_entity *se)
-{
- if (entity_is_task(se) && unlikely(task_of(se)->policy == SCHED_IDLE))
- return;
-
- for_each_sched_entity(se)
- cfs_rq_of(se)->last = se;
-}
-
-static void set_next_buddy(struct sched_entity *se)
-{
- if (entity_is_task(se) && unlikely(task_of(se)->policy == SCHED_IDLE))
- return;
-
- for_each_sched_entity(se)
- cfs_rq_of(se)->next = se;
-}
-
-static void set_skip_buddy(struct sched_entity *se)
-{
- for_each_sched_entity(se)
- cfs_rq_of(se)->skip = se;
-}
-
-/*
- * Preempt the current task with a newly woken task if needed:
- */
-static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_flags)
-{
- struct task_struct *curr = rq->curr;
- struct sched_entity *se = &curr->se, *pse = &p->se;
- struct cfs_rq *cfs_rq = task_cfs_rq(curr);
- int scale = cfs_rq->nr_running >= sched_nr_latency;
- int next_buddy_marked = 0;
-
- if (unlikely(se == pse))
- return;
-
- /*
- * This is possible from callers such as pull_task(), in which we
- * unconditionally check_prempt_curr() after an enqueue (which may have
- * lead to a throttle). This both saves work and prevents false
- * next-buddy nomination below.
- */
- if (unlikely(throttled_hierarchy(cfs_rq_of(pse))))
- return;
-
- if (sched_feat(NEXT_BUDDY) && scale && !(wake_flags & WF_FORK)) {
- set_next_buddy(pse);
- next_buddy_marked = 1;
- }
-
- /*
- * We can come here with TIF_NEED_RESCHED already set from new task
- * wake up path.
- *
- * Note: this also catches the edge-case of curr being in a throttled
- * group (e.g. via set_curr_task), since update_curr() (in the
- * enqueue of curr) will have resulted in resched being set. This
- * prevents us from potentially nominating it as a false LAST_BUDDY
- * below.
- */
- if (test_tsk_need_resched(curr))
- return;
-
- /* Idle tasks are by definition preempted by non-idle tasks. */
- if (unlikely(curr->policy == SCHED_IDLE) &&
- likely(p->policy != SCHED_IDLE))
- goto preempt;
-
- /*
- * Batch and idle tasks do not preempt non-idle tasks (their preemption
- * is driven by the tick):
- */
- if (unlikely(p->policy != SCHED_NORMAL))
- return;
-
- find_matching_se(&se, &pse);
- update_curr(cfs_rq_of(se));
- BUG_ON(!pse);
- if (wakeup_preempt_entity(se, pse) == 1) {
- /*
- * Bias pick_next to pick the sched entity that is
- * triggering this preemption.
- */
- if (!next_buddy_marked)
- set_next_buddy(pse);
- goto preempt;
- }
-
- return;
-
-preempt:
- resched_task(curr);
- /*
- * Only set the backward buddy when the current task is still
- * on the rq. This can happen when a wakeup gets interleaved
- * with schedule on the ->pre_schedule() or idle_balance()
- * point, either of which can * drop the rq lock.
- *
- * Also, during early boot the idle thread is in the fair class,
- * for obvious reasons its a bad idea to schedule back to it.
- */
- if (unlikely(!se->on_rq || curr == rq->idle))
- return;
-
- if (sched_feat(LAST_BUDDY) && scale && entity_is_task(se))
- set_last_buddy(se);
-}
-
-static struct task_struct *pick_next_task_fair(struct rq *rq)
-{
- struct task_struct *p;
- struct cfs_rq *cfs_rq = &rq->cfs;
- struct sched_entity *se;
-
- if (!cfs_rq->nr_running)
- return NULL;
-
- do {
- se = pick_next_entity(cfs_rq);
- set_next_entity(cfs_rq, se);
- cfs_rq = group_cfs_rq(se);
- } while (cfs_rq);
-
- p = task_of(se);
- hrtick_start_fair(rq, p);
-
- return p;
-}
-
-/*
- * Account for a descheduled task:
- */
-static void put_prev_task_fair(struct rq *rq, struct task_struct *prev)
-{
- struct sched_entity *se = &prev->se;
- struct cfs_rq *cfs_rq;
-
- for_each_sched_entity(se) {
- cfs_rq = cfs_rq_of(se);
- put_prev_entity(cfs_rq, se);
- }
-}
-
-/*
- * sched_yield() is very simple
- *
- * The magic of dealing with the ->skip buddy is in pick_next_entity.
- */
-static void yield_task_fair(struct rq *rq)
-{
- struct task_struct *curr = rq->curr;
- struct cfs_rq *cfs_rq = task_cfs_rq(curr);
- struct sched_entity *se = &curr->se;
-
- /*
- * Are we the only task in the tree?
- */
- if (unlikely(rq->nr_running == 1))
- return;
-
- clear_buddies(cfs_rq, se);
-
- if (curr->policy != SCHED_BATCH) {
- update_rq_clock(rq);
- /*
- * Update run-time statistics of the 'current'.
- */
- update_curr(cfs_rq);
- }
-
- set_skip_buddy(se);
-}
-
-static bool yield_to_task_fair(struct rq *rq, struct task_struct *p, bool preempt)
-{
- struct sched_entity *se = &p->se;
-
- /* throttled hierarchies are not runnable */
- if (!se->on_rq || throttled_hierarchy(cfs_rq_of(se)))
- return false;
-
- /* Tell the scheduler that we'd really like pse to run next. */
- set_next_buddy(se);
-
- yield_task_fair(rq);
-
- return true;
-}
-
-#ifdef CONFIG_SMP
-/**************************************************
- * Fair scheduling class load-balancing methods:
- */
-
-/*
- * pull_task - move a task from a remote runqueue to the local runqueue.
- * Both runqueues must be locked.
- */
-static void pull_task(struct rq *src_rq, struct task_struct *p,
- struct rq *this_rq, int this_cpu)
-{
- deactivate_task(src_rq, p, 0);
- set_task_cpu(p, this_cpu);
- activate_task(this_rq, p, 0);
- check_preempt_curr(this_rq, p, 0);
-}
-
-/*
- * Is this task likely cache-hot:
- */
-static int
-task_hot(struct task_struct *p, u64 now, struct sched_domain *sd)
-{
- s64 delta;
-
- if (p->sched_class != &fair_sched_class)
- return 0;
-
- if (unlikely(p->policy == SCHED_IDLE))
- return 0;
-
- /*
- * Buddy candidates are cache hot:
- */
- if (sched_feat(CACHE_HOT_BUDDY) && this_rq()->nr_running &&
- (&p->se == cfs_rq_of(&p->se)->next ||
- &p->se == cfs_rq_of(&p->se)->last))
- return 1;
-
- if (sysctl_sched_migration_cost == -1)
- return 1;
- if (sysctl_sched_migration_cost == 0)
- return 0;
-
- delta = now - p->se.exec_start;
-
- return delta < (s64)sysctl_sched_migration_cost;
-}
-
-/*
- * can_migrate_task - may task p from runqueue rq be migrated to this_cpu?
- */
-static
-int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu,
- struct sched_domain *sd, enum cpu_idle_type idle,
- int *all_pinned)
-{
- int tsk_cache_hot = 0;
- /*
- * We do not migrate tasks that are:
- * 1) running (obviously), or
- * 2) cannot be migrated to this CPU due to cpus_allowed, or
- * 3) are cache-hot on their current CPU.
- */
- if (!cpumask_test_cpu(this_cpu, tsk_cpus_allowed(p))) {
- schedstat_inc(p, se.statistics.nr_failed_migrations_affine);
- return 0;
- }
- *all_pinned = 0;
-
- if (task_running(rq, p)) {
- schedstat_inc(p, se.statistics.nr_failed_migrations_running);
- return 0;
- }
-
- /*
- * Aggressive migration if:
- * 1) task is cache cold, or
- * 2) too many balance attempts have failed.
- */
-
- tsk_cache_hot = task_hot(p, rq->clock_task, sd);
- if (!tsk_cache_hot ||
- sd->nr_balance_failed > sd->cache_nice_tries) {
-#ifdef CONFIG_SCHEDSTATS
- if (tsk_cache_hot) {
- schedstat_inc(sd, lb_hot_gained[idle]);
- schedstat_inc(p, se.statistics.nr_forced_migrations);
- }
-#endif
- return 1;
- }
-
- if (tsk_cache_hot) {
- schedstat_inc(p, se.statistics.nr_failed_migrations_hot);
- return 0;
- }
- return 1;
-}
-
-/*
- * move_one_task tries to move exactly one task from busiest to this_rq, as
- * part of active balancing operations within "domain".
- * Returns 1 if successful and 0 otherwise.
- *
- * Called with both runqueues locked.
- */
-static int
-move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,
- struct sched_domain *sd, enum cpu_idle_type idle)
-{
- struct task_struct *p, *n;
- struct cfs_rq *cfs_rq;
- int pinned = 0;
-
- for_each_leaf_cfs_rq(busiest, cfs_rq) {
- list_for_each_entry_safe(p, n, &cfs_rq->tasks, se.group_node) {
- if (throttled_lb_pair(task_group(p),
- busiest->cpu, this_cpu))
- break;
-
- if (!can_migrate_task(p, busiest, this_cpu,
- sd, idle, &pinned))
- continue;
-
- pull_task(busiest, p, this_rq, this_cpu);
- /*
- * Right now, this is only the second place pull_task()
- * is called, so we can safely collect pull_task()
- * stats here rather than inside pull_task().
- */
- schedstat_inc(sd, lb_gained[idle]);
- return 1;
- }
- }
-
- return 0;
-}
-
-static unsigned long
-balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
- unsigned long max_load_move, struct sched_domain *sd,
- enum cpu_idle_type idle, int *all_pinned,
- struct cfs_rq *busiest_cfs_rq)
-{
- int loops = 0, pulled = 0;
- long rem_load_move = max_load_move;
- struct task_struct *p, *n;
-
- if (max_load_move == 0)
- goto out;
-
- list_for_each_entry_safe(p, n, &busiest_cfs_rq->tasks, se.group_node) {
- if (loops++ > sysctl_sched_nr_migrate)
- break;
-
- if ((p->se.load.weight >> 1) > rem_load_move ||
- !can_migrate_task(p, busiest, this_cpu, sd, idle,
- all_pinned))
- continue;
-
- pull_task(busiest, p, this_rq, this_cpu);
- pulled++;
- rem_load_move -= p->se.load.weight;
-
-#ifdef CONFIG_PREEMPT
- /*
- * NEWIDLE balancing is a source of latency, so preemptible
- * kernels will stop after the first task is pulled to minimize
- * the critical section.
- */
- if (idle == CPU_NEWLY_IDLE)
- break;
-#endif
-
- /*
- * We only want to steal up to the prescribed amount of
- * weighted load.
- */
- if (rem_load_move <= 0)
- break;
- }
-out:
- /*
- * Right now, this is one of only two places pull_task() is called,
- * so we can safely collect pull_task() stats here rather than
- * inside pull_task().
- */
- schedstat_add(sd, lb_gained[idle], pulled);
-
- return max_load_move - rem_load_move;
-}
-
-#ifdef CONFIG_FAIR_GROUP_SCHED
-/*
- * update tg->load_weight by folding this cpu's load_avg
- */
-static int update_shares_cpu(struct task_group *tg, int cpu)
-{
- struct cfs_rq *cfs_rq;
- unsigned long flags;
- struct rq *rq;
-
- if (!tg->se[cpu])
- return 0;
-
- rq = cpu_rq(cpu);
- cfs_rq = tg->cfs_rq[cpu];
-
- raw_spin_lock_irqsave(&rq->lock, flags);
-
- update_rq_clock(rq);
- update_cfs_load(cfs_rq, 1);
-
- /*
- * We need to update shares after updating tg->load_weight in
- * order to adjust the weight of groups with long running tasks.
- */
- update_cfs_shares(cfs_rq);
-
- raw_spin_unlock_irqrestore(&rq->lock, flags);
-
- return 0;
-}
-
-static void update_shares(int cpu)
-{
- struct cfs_rq *cfs_rq;
- struct rq *rq = cpu_rq(cpu);
-
- rcu_read_lock();
- /*
- * Iterates the task_group tree in a bottom up fashion, see
- * list_add_leaf_cfs_rq() for details.
- */
- for_each_leaf_cfs_rq(rq, cfs_rq) {
- /* throttled entities do not contribute to load */
- if (throttled_hierarchy(cfs_rq))
- continue;
-
- update_shares_cpu(cfs_rq->tg, cpu);
- }
- rcu_read_unlock();
-}
-
-/*
- * Compute the cpu's hierarchical load factor for each task group.
- * This needs to be done in a top-down fashion because the load of a child
- * group is a fraction of its parents load.
- */
-static int tg_load_down(struct task_group *tg, void *data)
-{
- unsigned long load;
- long cpu = (long)data;
-
- if (!tg->parent) {
- load = cpu_rq(cpu)->load.weight;
- } else {
- load = tg->parent->cfs_rq[cpu]->h_load;
- load *= tg->se[cpu]->load.weight;
- load /= tg->parent->cfs_rq[cpu]->load.weight + 1;
- }
-
- tg->cfs_rq[cpu]->h_load = load;
-
- return 0;
-}
-
-static void update_h_load(long cpu)
-{
- walk_tg_tree(tg_load_down, tg_nop, (void *)cpu);
-}
-
-static unsigned long
-load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest,
- unsigned long max_load_move,
- struct sched_domain *sd, enum cpu_idle_type idle,
- int *all_pinned)
-{
- long rem_load_move = max_load_move;
- struct cfs_rq *busiest_cfs_rq;
-
- rcu_read_lock();
- update_h_load(cpu_of(busiest));
-
- for_each_leaf_cfs_rq(busiest, busiest_cfs_rq) {
- unsigned long busiest_h_load = busiest_cfs_rq->h_load;
- unsigned long busiest_weight = busiest_cfs_rq->load.weight;
- u64 rem_load, moved_load;
-
- /*
- * empty group or part of a throttled hierarchy
- */
- if (!busiest_cfs_rq->task_weight ||
- throttled_lb_pair(busiest_cfs_rq->tg, cpu_of(busiest), this_cpu))
- continue;
-
- rem_load = (u64)rem_load_move * busiest_weight;
- rem_load = div_u64(rem_load, busiest_h_load + 1);
-
- moved_load = balance_tasks(this_rq, this_cpu, busiest,
- rem_load, sd, idle, all_pinned,
- busiest_cfs_rq);
-
- if (!moved_load)
- continue;
-
- moved_load *= busiest_h_load;
- moved_load = div_u64(moved_load, busiest_weight + 1);
-
- rem_load_move -= moved_load;
- if (rem_load_move < 0)
- break;
- }
- rcu_read_unlock();
-
- return max_load_move - rem_load_move;
-}
-#else
-static inline void update_shares(int cpu)
-{
-}
-
-static unsigned long
-load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest,
- unsigned long max_load_move,
- struct sched_domain *sd, enum cpu_idle_type idle,
- int *all_pinned)
-{
- return balance_tasks(this_rq, this_cpu, busiest,
- max_load_move, sd, idle, all_pinned,
- &busiest->cfs);
-}
-#endif
-
-/*
- * move_tasks tries to move up to max_load_move weighted load from busiest to
- * this_rq, as part of a balancing operation within domain "sd".
- * Returns 1 if successful and 0 otherwise.
- *
- * Called with both runqueues locked.
- */
-static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
- unsigned long max_load_move,
- struct sched_domain *sd, enum cpu_idle_type idle,
- int *all_pinned)
-{
- unsigned long total_load_moved = 0, load_moved;
-
- do {
- load_moved = load_balance_fair(this_rq, this_cpu, busiest,
- max_load_move - total_load_moved,
- sd, idle, all_pinned);
-
- total_load_moved += load_moved;
-
-#ifdef CONFIG_PREEMPT
- /*
- * NEWIDLE balancing is a source of latency, so preemptible
- * kernels will stop after the first task is pulled to minimize
- * the critical section.
- */
- if (idle == CPU_NEWLY_IDLE && this_rq->nr_running)
- break;
-
- if (raw_spin_is_contended(&this_rq->lock) ||
- raw_spin_is_contended(&busiest->lock))
- break;
-#endif
- } while (load_moved && max_load_move > total_load_moved);
-
- return total_load_moved > 0;
-}
-
-/********** Helpers for find_busiest_group ************************/
-/*
- * sd_lb_stats - Structure to store the statistics of a sched_domain
- * during load balancing.
- */
-struct sd_lb_stats {
- struct sched_group *busiest; /* Busiest group in this sd */
- struct sched_group *this; /* Local group in this sd */
- unsigned long total_load; /* Total load of all groups in sd */
- unsigned long total_pwr; /* Total power of all groups in sd */
- unsigned long avg_load; /* Average load across all groups in sd */
-
- /** Statistics of this group */
- unsigned long this_load;
- unsigned long this_load_per_task;
- unsigned long this_nr_running;
- unsigned long this_has_capacity;
- unsigned int this_idle_cpus;
-
- /* Statistics of the busiest group */
- unsigned int busiest_idle_cpus;
- unsigned long max_load;
- unsigned long busiest_load_per_task;
- unsigned long busiest_nr_running;
- unsigned long busiest_group_capacity;
- unsigned long busiest_has_capacity;
- unsigned int busiest_group_weight;
-
- int group_imb; /* Is there imbalance in this sd */
-#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
- int power_savings_balance; /* Is powersave balance needed for this sd */
- struct sched_group *group_min; /* Least loaded group in sd */
- struct sched_group *group_leader; /* Group which relieves group_min */
- unsigned long min_load_per_task; /* load_per_task in group_min */
- unsigned long leader_nr_running; /* Nr running of group_leader */
- unsigned long min_nr_running; /* Nr running of group_min */
-#endif
-};
-
-/*
- * sg_lb_stats - stats of a sched_group required for load_balancing
- */
-struct sg_lb_stats {
- unsigned long avg_load; /*Avg load across the CPUs of the group */
- unsigned long group_load; /* Total load over the CPUs of the group */
- unsigned long sum_nr_running; /* Nr tasks running in the group */
- unsigned long sum_weighted_load; /* Weighted load of group's tasks */
- unsigned long group_capacity;
- unsigned long idle_cpus;
- unsigned long group_weight;
- int group_imb; /* Is there an imbalance in the group ? */
- int group_has_capacity; /* Is there extra capacity in the group? */
-};
-
-/**
- * get_sd_load_idx - Obtain the load index for a given sched domain.
- * @sd: The sched_domain whose load_idx is to be obtained.
- * @idle: The Idle status of the CPU for whose sd load_icx is obtained.
- */
-static inline int get_sd_load_idx(struct sched_domain *sd,
- enum cpu_idle_type idle)
-{
- int load_idx;
-
- switch (idle) {
- case CPU_NOT_IDLE:
- load_idx = sd->busy_idx;
- break;
-
- case CPU_NEWLY_IDLE:
- load_idx = sd->newidle_idx;
- break;
- default:
- load_idx = sd->idle_idx;
- break;
- }
-
- return load_idx;
-}
-
-
-#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
-/**
- * init_sd_power_savings_stats - Initialize power savings statistics for
- * the given sched_domain, during load balancing.
- *
- * @sd: Sched domain whose power-savings statistics are to be initialized.
- * @sds: Variable containing the statistics for sd.
- * @idle: Idle status of the CPU at which we're performing load-balancing.
- */
-static inline void init_sd_power_savings_stats(struct sched_domain *sd,
- struct sd_lb_stats *sds, enum cpu_idle_type idle)
-{
- /*
- * Busy processors will not participate in power savings
- * balance.
- */
- if (idle == CPU_NOT_IDLE || !(sd->flags & SD_POWERSAVINGS_BALANCE))
- sds->power_savings_balance = 0;
- else {
- sds->power_savings_balance = 1;
- sds->min_nr_running = ULONG_MAX;
- sds->leader_nr_running = 0;
- }
-}
-
-/**
- * update_sd_power_savings_stats - Update the power saving stats for a
- * sched_domain while performing load balancing.
- *
- * @group: sched_group belonging to the sched_domain under consideration.
- * @sds: Variable containing the statistics of the sched_domain
- * @local_group: Does group contain the CPU for which we're performing
- * load balancing ?
- * @sgs: Variable containing the statistics of the group.
- */
-static inline void update_sd_power_savings_stats(struct sched_group *group,
- struct sd_lb_stats *sds, int local_group, struct sg_lb_stats *sgs)
-{
-
- if (!sds->power_savings_balance)
- return;
-
- /*
- * If the local group is idle or completely loaded
- * no need to do power savings balance at this domain
- */
- if (local_group && (sds->this_nr_running >= sgs->group_capacity ||
- !sds->this_nr_running))
- sds->power_savings_balance = 0;
-
- /*
- * If a group is already running at full capacity or idle,
- * don't include that group in power savings calculations
- */
- if (!sds->power_savings_balance ||
- sgs->sum_nr_running >= sgs->group_capacity ||
- !sgs->sum_nr_running)
- return;
-
- /*
- * Calculate the group which has the least non-idle load.
- * This is the group from where we need to pick up the load
- * for saving power
- */
- if ((sgs->sum_nr_running < sds->min_nr_running) ||
- (sgs->sum_nr_running == sds->min_nr_running &&
- group_first_cpu(group) > group_first_cpu(sds->group_min))) {
- sds->group_min = group;
- sds->min_nr_running = sgs->sum_nr_running;
- sds->min_load_per_task = sgs->sum_weighted_load /
- sgs->sum_nr_running;
- }
-
- /*
- * Calculate the group which is almost near its
- * capacity but still has some space to pick up some load
- * from other group and save more power
- */
- if (sgs->sum_nr_running + 1 > sgs->group_capacity)
- return;
-
- if (sgs->sum_nr_running > sds->leader_nr_running ||
- (sgs->sum_nr_running == sds->leader_nr_running &&
- group_first_cpu(group) < group_first_cpu(sds->group_leader))) {
- sds->group_leader = group;
- sds->leader_nr_running = sgs->sum_nr_running;
- }
-}
-
-/**
- * check_power_save_busiest_group - see if there is potential for some power-savings balance
- * @sds: Variable containing the statistics of the sched_domain
- * under consideration.
- * @this_cpu: Cpu at which we're currently performing load-balancing.
- * @imbalance: Variable to store the imbalance.
- *
- * Description:
- * Check if we have potential to perform some power-savings balance.
- * If yes, set the busiest group to be the least loaded group in the
- * sched_domain, so that it's CPUs can be put to idle.
- *
- * Returns 1 if there is potential to perform power-savings balance.
- * Else returns 0.
- */
-static inline int check_power_save_busiest_group(struct sd_lb_stats *sds,
- int this_cpu, unsigned long *imbalance)
-{
- if (!sds->power_savings_balance)
- return 0;
-
- if (sds->this != sds->group_leader ||
- sds->group_leader == sds->group_min)
- return 0;
-
- *imbalance = sds->min_load_per_task;
- sds->busiest = sds->group_min;
-
- return 1;
-
-}
-#else /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
-static inline void init_sd_power_savings_stats(struct sched_domain *sd,
- struct sd_lb_stats *sds, enum cpu_idle_type idle)
-{
- return;
-}
-
-static inline void update_sd_power_savings_stats(struct sched_group *group,
- struct sd_lb_stats *sds, int local_group, struct sg_lb_stats *sgs)
-{
- return;
-}
-
-static inline int check_power_save_busiest_group(struct sd_lb_stats *sds,
- int this_cpu, unsigned long *imbalance)
-{
- return 0;
-}
-#endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
-
-
-unsigned long default_scale_freq_power(struct sched_domain *sd, int cpu)
-{
- return SCHED_POWER_SCALE;
-}
-
-unsigned long __weak arch_scale_freq_power(struct sched_domain *sd, int cpu)
-{
- return default_scale_freq_power(sd, cpu);
-}
-
-unsigned long default_scale_smt_power(struct sched_domain *sd, int cpu)
-{
- unsigned long weight = sd->span_weight;
- unsigned long smt_gain = sd->smt_gain;
-
- smt_gain /= weight;
-
- return smt_gain;
-}
-
-unsigned long __weak arch_scale_smt_power(struct sched_domain *sd, int cpu)
-{
- return default_scale_smt_power(sd, cpu);
-}
-
-unsigned long scale_rt_power(int cpu)
-{
- struct rq *rq = cpu_rq(cpu);
- u64 total, available;
-
- total = sched_avg_period() + (rq->clock - rq->age_stamp);
-
- if (unlikely(total < rq->rt_avg)) {
- /* Ensures that power won't end up being negative */
- available = 0;
- } else {
- available = total - rq->rt_avg;
- }
-
- if (unlikely((s64)total < SCHED_POWER_SCALE))
- total = SCHED_POWER_SCALE;
-
- total >>= SCHED_POWER_SHIFT;
-
- return div_u64(available, total);
-}
-
-static void update_cpu_power(struct sched_domain *sd, int cpu)
-{
- unsigned long weight = sd->span_weight;
- unsigned long power = SCHED_POWER_SCALE;
- struct sched_group *sdg = sd->groups;
-
- if ((sd->flags & SD_SHARE_CPUPOWER) && weight > 1) {
- if (sched_feat(ARCH_POWER))
- power *= arch_scale_smt_power(sd, cpu);
- else
- power *= default_scale_smt_power(sd, cpu);
-
- power >>= SCHED_POWER_SHIFT;
- }
-
- sdg->sgp->power_orig = power;
-
- if (sched_feat(ARCH_POWER))
- power *= arch_scale_freq_power(sd, cpu);
- else
- power *= default_scale_freq_power(sd, cpu);
-
- power >>= SCHED_POWER_SHIFT;
-
- power *= scale_rt_power(cpu);
- power >>= SCHED_POWER_SHIFT;
-
- if (!power)
- power = 1;
-
- cpu_rq(cpu)->cpu_power = power;
- sdg->sgp->power = power;
-}
-
-void update_group_power(struct sched_domain *sd, int cpu)
-{
- struct sched_domain *child = sd->child;
- struct sched_group *group, *sdg = sd->groups;
- unsigned long power;
-
- if (!child) {
- update_cpu_power(sd, cpu);
- return;
- }
-
- power = 0;
-
- group = child->groups;
- do {
- power += group->sgp->power;
- group = group->next;
- } while (group != child->groups);
-
- sdg->sgp->power = power;
-}
-
-/*
- * Try and fix up capacity for tiny siblings, this is needed when
- * things like SD_ASYM_PACKING need f_b_g to select another sibling
- * which on its own isn't powerful enough.
- *
- * See update_sd_pick_busiest() and check_asym_packing().
- */
-static inline int
-fix_small_capacity(struct sched_domain *sd, struct sched_group *group)
-{
- /*
- * Only siblings can have significantly less than SCHED_POWER_SCALE
- */
- if (!(sd->flags & SD_SHARE_CPUPOWER))
- return 0;
-
- /*
- * If ~90% of the cpu_power is still there, we're good.
- */
- if (group->sgp->power * 32 > group->sgp->power_orig * 29)
- return 1;
-
- return 0;
-}
-
-/**
- * update_sg_lb_stats - Update sched_group's statistics for load balancing.
- * @sd: The sched_domain whose statistics are to be updated.
- * @group: sched_group whose statistics are to be updated.
- * @this_cpu: Cpu for which load balance is currently performed.
- * @idle: Idle status of this_cpu
- * @load_idx: Load index of sched_domain of this_cpu for load calc.
- * @local_group: Does group contain this_cpu.
- * @cpus: Set of cpus considered for load balancing.
- * @balance: Should we balance.
- * @sgs: variable to hold the statistics for this group.
- */
-static inline void update_sg_lb_stats(struct sched_domain *sd,
- struct sched_group *group, int this_cpu,
- enum cpu_idle_type idle, int load_idx,
- int local_group, const struct cpumask *cpus,
- int *balance, struct sg_lb_stats *sgs)
-{
- unsigned long load, max_cpu_load, min_cpu_load, max_nr_running;
- int i;
- unsigned int balance_cpu = -1, first_idle_cpu = 0;
- unsigned long avg_load_per_task = 0;
-
- if (local_group)
- balance_cpu = group_first_cpu(group);
-
- /* Tally up the load of all CPUs in the group */
- max_cpu_load = 0;
- min_cpu_load = ~0UL;
- max_nr_running = 0;
-
- for_each_cpu_and(i, sched_group_cpus(group), cpus) {
- struct rq *rq = cpu_rq(i);
-
- /* Bias balancing toward cpus of our domain */
- if (local_group) {
- if (idle_cpu(i) && !first_idle_cpu) {
- first_idle_cpu = 1;
- balance_cpu = i;
- }
-
- load = target_load(i, load_idx);
- } else {
- load = source_load(i, load_idx);
- if (load > max_cpu_load) {
- max_cpu_load = load;
- max_nr_running = rq->nr_running;
- }
- if (min_cpu_load > load)
- min_cpu_load = load;
- }
-
- sgs->group_load += load;
- sgs->sum_nr_running += rq->nr_running;
- sgs->sum_weighted_load += weighted_cpuload(i);
- if (idle_cpu(i))
- sgs->idle_cpus++;
- }
-
- /*
- * First idle cpu or the first cpu(busiest) in this sched group
- * is eligible for doing load balancing at this and above
- * domains. In the newly idle case, we will allow all the cpu's
- * to do the newly idle load balance.
- */
- if (idle != CPU_NEWLY_IDLE && local_group) {
- if (balance_cpu != this_cpu) {
- *balance = 0;
- return;
- }
- update_group_power(sd, this_cpu);
- }
-
- /* Adjust by relative CPU power of the group */
- sgs->avg_load = (sgs->group_load*SCHED_POWER_SCALE) / group->sgp->power;
-
- /*
- * Consider the group unbalanced when the imbalance is larger
- * than the average weight of a task.
- *
- * APZ: with cgroup the avg task weight can vary wildly and
- * might not be a suitable number - should we keep a
- * normalized nr_running number somewhere that negates
- * the hierarchy?
- */
- if (sgs->sum_nr_running)
- avg_load_per_task = sgs->sum_weighted_load / sgs->sum_nr_running;
-
- if ((max_cpu_load - min_cpu_load) >= avg_load_per_task && max_nr_running > 1)
- sgs->group_imb = 1;
-
- sgs->group_capacity = DIV_ROUND_CLOSEST(group->sgp->power,
- SCHED_POWER_SCALE);
- if (!sgs->group_capacity)
- sgs->group_capacity = fix_small_capacity(sd, group);
- sgs->group_weight = group->group_weight;
-
- if (sgs->group_capacity > sgs->sum_nr_running)
- sgs->group_has_capacity = 1;
-}
-
-/**
- * update_sd_pick_busiest - return 1 on busiest group
- * @sd: sched_domain whose statistics are to be checked
- * @sds: sched_domain statistics
- * @sg: sched_group candidate to be checked for being the busiest
- * @sgs: sched_group statistics
- * @this_cpu: the current cpu
- *
- * Determine if @sg is a busier group than the previously selected
- * busiest group.
- */
-static bool update_sd_pick_busiest(struct sched_domain *sd,
- struct sd_lb_stats *sds,
- struct sched_group *sg,
- struct sg_lb_stats *sgs,
- int this_cpu)
-{
- if (sgs->avg_load <= sds->max_load)
- return false;
-
- if (sgs->sum_nr_running > sgs->group_capacity)
- return true;
-
- if (sgs->group_imb)
- return true;
-
- /*
- * ASYM_PACKING needs to move all the work to the lowest
- * numbered CPUs in the group, therefore mark all groups
- * higher than ourself as busy.
- */
- if ((sd->flags & SD_ASYM_PACKING) && sgs->sum_nr_running &&
- this_cpu < group_first_cpu(sg)) {
- if (!sds->busiest)
- return true;
-
- if (group_first_cpu(sds->busiest) > group_first_cpu(sg))
- return true;
- }
-
- return false;
-}
-
-/**
- * update_sd_lb_stats - Update sched_domain's statistics for load balancing.
- * @sd: sched_domain whose statistics are to be updated.
- * @this_cpu: Cpu for which load balance is currently performed.
- * @idle: Idle status of this_cpu
- * @cpus: Set of cpus considered for load balancing.
- * @balance: Should we balance.
- * @sds: variable to hold the statistics for this sched_domain.
- */
-static inline void update_sd_lb_stats(struct sched_domain *sd, int this_cpu,
- enum cpu_idle_type idle, const struct cpumask *cpus,
- int *balance, struct sd_lb_stats *sds)
-{
- struct sched_domain *child = sd->child;
- struct sched_group *sg = sd->groups;
- struct sg_lb_stats sgs;
- int load_idx, prefer_sibling = 0;
-
- if (child && child->flags & SD_PREFER_SIBLING)
- prefer_sibling = 1;
-
- init_sd_power_savings_stats(sd, sds, idle);
- load_idx = get_sd_load_idx(sd, idle);
-
- do {
- int local_group;
-
- local_group = cpumask_test_cpu(this_cpu, sched_group_cpus(sg));
- memset(&sgs, 0, sizeof(sgs));
- update_sg_lb_stats(sd, sg, this_cpu, idle, load_idx,
- local_group, cpus, balance, &sgs);
-
- if (local_group && !(*balance))
- return;
-
- sds->total_load += sgs.group_load;
- sds->total_pwr += sg->sgp->power;
-
- /*
- * In case the child domain prefers tasks go to siblings
- * first, lower the sg capacity to one so that we'll try
- * and move all the excess tasks away. We lower the capacity
- * of a group only if the local group has the capacity to fit
- * these excess tasks, i.e. nr_running < group_capacity. The
- * extra check prevents the case where you always pull from the
- * heaviest group when it is already under-utilized (possible
- * with a large weight task outweighs the tasks on the system).
- */
- if (prefer_sibling && !local_group && sds->this_has_capacity)
- sgs.group_capacity = min(sgs.group_capacity, 1UL);
-
- if (local_group) {
- sds->this_load = sgs.avg_load;
- sds->this = sg;
- sds->this_nr_running = sgs.sum_nr_running;
- sds->this_load_per_task = sgs.sum_weighted_load;
- sds->this_has_capacity = sgs.group_has_capacity;
- sds->this_idle_cpus = sgs.idle_cpus;
- } else if (update_sd_pick_busiest(sd, sds, sg, &sgs, this_cpu)) {
- sds->max_load = sgs.avg_load;
- sds->busiest = sg;
- sds->busiest_nr_running = sgs.sum_nr_running;
- sds->busiest_idle_cpus = sgs.idle_cpus;
- sds->busiest_group_capacity = sgs.group_capacity;
- sds->busiest_load_per_task = sgs.sum_weighted_load;
- sds->busiest_has_capacity = sgs.group_has_capacity;
- sds->busiest_group_weight = sgs.group_weight;
- sds->group_imb = sgs.group_imb;
- }
-
- update_sd_power_savings_stats(sg, sds, local_group, &sgs);
- sg = sg->next;
- } while (sg != sd->groups);
-}
-
-/**
- * check_asym_packing - Check to see if the group is packed into the
- * sched doman.
- *
- * This is primarily intended to used at the sibling level. Some
- * cores like POWER7 prefer to use lower numbered SMT threads. In the
- * case of POWER7, it can move to lower SMT modes only when higher
- * threads are idle. When in lower SMT modes, the threads will
- * perform better since they share less core resources. Hence when we
- * have idle threads, we want them to be the higher ones.
- *
- * This packing function is run on idle threads. It checks to see if
- * the busiest CPU in this domain (core in the P7 case) has a higher
- * CPU number than the packing function is being run on. Here we are
- * assuming lower CPU number will be equivalent to lower a SMT thread
- * number.
- *
- * Returns 1 when packing is required and a task should be moved to
- * this CPU. The amount of the imbalance is returned in *imbalance.
- *
- * @sd: The sched_domain whose packing is to be checked.
- * @sds: Statistics of the sched_domain which is to be packed
- * @this_cpu: The cpu at whose sched_domain we're performing load-balance.
- * @imbalance: returns amount of imbalanced due to packing.
- */
-static int check_asym_packing(struct sched_domain *sd,
- struct sd_lb_stats *sds,
- int this_cpu, unsigned long *imbalance)
-{
- int busiest_cpu;
-
- if (!(sd->flags & SD_ASYM_PACKING))
- return 0;
-
- if (!sds->busiest)
- return 0;
-
- busiest_cpu = group_first_cpu(sds->busiest);
- if (this_cpu > busiest_cpu)
- return 0;
-
- *imbalance = DIV_ROUND_CLOSEST(sds->max_load * sds->busiest->sgp->power,
- SCHED_POWER_SCALE);
- return 1;
-}
-
-/**
- * fix_small_imbalance - Calculate the minor imbalance that exists
- * amongst the groups of a sched_domain, during
- * load balancing.
- * @sds: Statistics of the sched_domain whose imbalance is to be calculated.
- * @this_cpu: The cpu at whose sched_domain we're performing load-balance.
- * @imbalance: Variable to store the imbalance.
- */
-static inline void fix_small_imbalance(struct sd_lb_stats *sds,
- int this_cpu, unsigned long *imbalance)
-{
- unsigned long tmp, pwr_now = 0, pwr_move = 0;
- unsigned int imbn = 2;
- unsigned long scaled_busy_load_per_task;
-
- if (sds->this_nr_running) {
- sds->this_load_per_task /= sds->this_nr_running;
- if (sds->busiest_load_per_task >
- sds->this_load_per_task)
- imbn = 1;
- } else
- sds->this_load_per_task =
- cpu_avg_load_per_task(this_cpu);
-
- scaled_busy_load_per_task = sds->busiest_load_per_task
- * SCHED_POWER_SCALE;
- scaled_busy_load_per_task /= sds->busiest->sgp->power;
-
- if (sds->max_load - sds->this_load + scaled_busy_load_per_task >=
- (scaled_busy_load_per_task * imbn)) {
- *imbalance = sds->busiest_load_per_task;
- return;
- }
-
- /*
- * OK, we don't have enough imbalance to justify moving tasks,
- * however we may be able to increase total CPU power used by
- * moving them.
- */
-
- pwr_now += sds->busiest->sgp->power *
- min(sds->busiest_load_per_task, sds->max_load);
- pwr_now += sds->this->sgp->power *
- min(sds->this_load_per_task, sds->this_load);
- pwr_now /= SCHED_POWER_SCALE;
-
- /* Amount of load we'd subtract */
- tmp = (sds->busiest_load_per_task * SCHED_POWER_SCALE) /
- sds->busiest->sgp->power;
- if (sds->max_load > tmp)
- pwr_move += sds->busiest->sgp->power *
- min(sds->busiest_load_per_task, sds->max_load - tmp);
-
- /* Amount of load we'd add */
- if (sds->max_load * sds->busiest->sgp->power <
- sds->busiest_load_per_task * SCHED_POWER_SCALE)
- tmp = (sds->max_load * sds->busiest->sgp->power) /
- sds->this->sgp->power;
- else
- tmp = (sds->busiest_load_per_task * SCHED_POWER_SCALE) /
- sds->this->sgp->power;
- pwr_move += sds->this->sgp->power *
- min(sds->this_load_per_task, sds->this_load + tmp);
- pwr_move /= SCHED_POWER_SCALE;
-
- /* Move if we gain throughput */
- if (pwr_move > pwr_now)
- *imbalance = sds->busiest_load_per_task;
-}
-
-/**
- * calculate_imbalance - Calculate the amount of imbalance present within the
- * groups of a given sched_domain during load balance.
- * @sds: statistics of the sched_domain whose imbalance is to be calculated.
- * @this_cpu: Cpu for which currently load balance is being performed.
- * @imbalance: The variable to store the imbalance.
- */
-static inline void calculate_imbalance(struct sd_lb_stats *sds, int this_cpu,
- unsigned long *imbalance)
-{
- unsigned long max_pull, load_above_capacity = ~0UL;
-
- sds->busiest_load_per_task /= sds->busiest_nr_running;
- if (sds->group_imb) {
- sds->busiest_load_per_task =
- min(sds->busiest_load_per_task, sds->avg_load);
- }
-
- /*
- * In the presence of smp nice balancing, certain scenarios can have
- * max load less than avg load(as we skip the groups at or below
- * its cpu_power, while calculating max_load..)
- */
- if (sds->max_load < sds->avg_load) {
- *imbalance = 0;
- return fix_small_imbalance(sds, this_cpu, imbalance);
- }
-
- if (!sds->group_imb) {
- /*
- * Don't want to pull so many tasks that a group would go idle.
- */
- load_above_capacity = (sds->busiest_nr_running -
- sds->busiest_group_capacity);
-
- load_above_capacity *= (SCHED_LOAD_SCALE * SCHED_POWER_SCALE);
-
- load_above_capacity /= sds->busiest->sgp->power;
- }
-
- /*
- * We're trying to get all the cpus to the average_load, so we don't
- * want to push ourselves above the average load, nor do we wish to
- * reduce the max loaded cpu below the average load. At the same time,
- * we also don't want to reduce the group load below the group capacity
- * (so that we can implement power-savings policies etc). Thus we look
- * for the minimum possible imbalance.
- * Be careful of negative numbers as they'll appear as very large values
- * with unsigned longs.
- */
- max_pull = min(sds->max_load - sds->avg_load, load_above_capacity);
-
- /* How much load to actually move to equalise the imbalance */
- *imbalance = min(max_pull * sds->busiest->sgp->power,
- (sds->avg_load - sds->this_load) * sds->this->sgp->power)
- / SCHED_POWER_SCALE;
-
- /*
- * if *imbalance is less than the average load per runnable task
- * there is no guarantee that any tasks will be moved so we'll have
- * a think about bumping its value to force at least one task to be
- * moved
- */
- if (*imbalance < sds->busiest_load_per_task)
- return fix_small_imbalance(sds, this_cpu, imbalance);
-
-}
-
-/******* find_busiest_group() helpers end here *********************/
-
-/**
- * find_busiest_group - Returns the busiest group within the sched_domain
- * if there is an imbalance. If there isn't an imbalance, and
- * the user has opted for power-savings, it returns a group whose
- * CPUs can be put to idle by rebalancing those tasks elsewhere, if
- * such a group exists.
- *
- * Also calculates the amount of weighted load which should be moved
- * to restore balance.
- *
- * @sd: The sched_domain whose busiest group is to be returned.
- * @this_cpu: The cpu for which load balancing is currently being performed.
- * @imbalance: Variable which stores amount of weighted load which should
- * be moved to restore balance/put a group to idle.
- * @idle: The idle status of this_cpu.
- * @cpus: The set of CPUs under consideration for load-balancing.
- * @balance: Pointer to a variable indicating if this_cpu
- * is the appropriate cpu to perform load balancing at this_level.
- *
- * Returns: - the busiest group if imbalance exists.
- * - If no imbalance and user has opted for power-savings balance,
- * return the least loaded group whose CPUs can be
- * put to idle by rebalancing its tasks onto our group.
- */
-static struct sched_group *
-find_busiest_group(struct sched_domain *sd, int this_cpu,
- unsigned long *imbalance, enum cpu_idle_type idle,
- const struct cpumask *cpus, int *balance)
-{
- struct sd_lb_stats sds;
-
- memset(&sds, 0, sizeof(sds));
-
- /*
- * Compute the various statistics relavent for load balancing at
- * this level.
- */
- update_sd_lb_stats(sd, this_cpu, idle, cpus, balance, &sds);
-
- /*
- * this_cpu is not the appropriate cpu to perform load balancing at
- * this level.
- */
- if (!(*balance))
- goto ret;
-
- if ((idle == CPU_IDLE || idle == CPU_NEWLY_IDLE) &&
- check_asym_packing(sd, &sds, this_cpu, imbalance))
- return sds.busiest;
-
- /* There is no busy sibling group to pull tasks from */
- if (!sds.busiest || sds.busiest_nr_running == 0)
- goto out_balanced;
-
- sds.avg_load = (SCHED_POWER_SCALE * sds.total_load) / sds.total_pwr;
-
- /*
- * If the busiest group is imbalanced the below checks don't
- * work because they assumes all things are equal, which typically
- * isn't true due to cpus_allowed constraints and the like.
- */
- if (sds.group_imb)
- goto force_balance;
-
- /* SD_BALANCE_NEWIDLE trumps SMP nice when underutilized */
- if (idle == CPU_NEWLY_IDLE && sds.this_has_capacity &&
- !sds.busiest_has_capacity)
- goto force_balance;
-
- /*
- * If the local group is more busy than the selected busiest group
- * don't try and pull any tasks.
- */
- if (sds.this_load >= sds.max_load)
- goto out_balanced;
-
- /*
- * Don't pull any tasks if this group is already above the domain
- * average load.
- */
- if (sds.this_load >= sds.avg_load)
- goto out_balanced;
-
- if (idle == CPU_IDLE) {
- /*
- * This cpu is idle. If the busiest group load doesn't
- * have more tasks than the number of available cpu's and
- * there is no imbalance between this and busiest group
- * wrt to idle cpu's, it is balanced.
- */
- if ((sds.this_idle_cpus <= sds.busiest_idle_cpus + 1) &&
- sds.busiest_nr_running <= sds.busiest_group_weight)
- goto out_balanced;
- } else {
- /*
- * In the CPU_NEWLY_IDLE, CPU_NOT_IDLE cases, use
- * imbalance_pct to be conservative.
- */
- if (100 * sds.max_load <= sd->imbalance_pct * sds.this_load)
- goto out_balanced;
- }
-
-force_balance:
- /* Looks like there is an imbalance. Compute it */
- calculate_imbalance(&sds, this_cpu, imbalance);
- return sds.busiest;
-
-out_balanced:
- /*
- * There is no obvious imbalance. But check if we can do some balancing
- * to save power.
- */
- if (check_power_save_busiest_group(&sds, this_cpu, imbalance))
- return sds.busiest;
-ret:
- *imbalance = 0;
- return NULL;
-}
-
-/*
- * find_busiest_queue - find the busiest runqueue among the cpus in group.
- */
-static struct rq *
-find_busiest_queue(struct sched_domain *sd, struct sched_group *group,
- enum cpu_idle_type idle, unsigned long imbalance,
- const struct cpumask *cpus)
-{
- struct rq *busiest = NULL, *rq;
- unsigned long max_load = 0;
- int i;
-
- for_each_cpu(i, sched_group_cpus(group)) {
- unsigned long power = power_of(i);
- unsigned long capacity = DIV_ROUND_CLOSEST(power,
- SCHED_POWER_SCALE);
- unsigned long wl;
-
- if (!capacity)
- capacity = fix_small_capacity(sd, group);
-
- if (!cpumask_test_cpu(i, cpus))
- continue;
-
- rq = cpu_rq(i);
- wl = weighted_cpuload(i);
-
- /*
- * When comparing with imbalance, use weighted_cpuload()
- * which is not scaled with the cpu power.
- */
- if (capacity && rq->nr_running == 1 && wl > imbalance)
- continue;
-
- /*
- * For the load comparisons with the other cpu's, consider
- * the weighted_cpuload() scaled with the cpu power, so that
- * the load can be moved away from the cpu that is potentially
- * running at a lower capacity.
- */
- wl = (wl * SCHED_POWER_SCALE) / power;
-
- if (wl > max_load) {
- max_load = wl;
- busiest = rq;
- }
- }
-
- return busiest;
-}
-
-/*
- * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but
- * so long as it is large enough.
- */
-#define MAX_PINNED_INTERVAL 512
-
-/* Working cpumask for load_balance and load_balance_newidle. */
-DEFINE_PER_CPU(cpumask_var_t, load_balance_tmpmask);
-
-static int need_active_balance(struct sched_domain *sd, int idle,
- int busiest_cpu, int this_cpu)
-{
- if (idle == CPU_NEWLY_IDLE) {
-
- /*
- * ASYM_PACKING needs to force migrate tasks from busy but
- * higher numbered CPUs in order to pack all tasks in the
- * lowest numbered CPUs.
- */
- if ((sd->flags & SD_ASYM_PACKING) && busiest_cpu > this_cpu)
- return 1;
-
- /*
- * The only task running in a non-idle cpu can be moved to this
- * cpu in an attempt to completely freeup the other CPU
- * package.
- *
- * The package power saving logic comes from
- * find_busiest_group(). If there are no imbalance, then
- * f_b_g() will return NULL. However when sched_mc={1,2} then
- * f_b_g() will select a group from which a running task may be
- * pulled to this cpu in order to make the other package idle.
- * If there is no opportunity to make a package idle and if
- * there are no imbalance, then f_b_g() will return NULL and no
- * action will be taken in load_balance_newidle().
- *
- * Under normal task pull operation due to imbalance, there
- * will be more than one task in the source run queue and
- * move_tasks() will succeed. ld_moved will be true and this
- * active balance code will not be triggered.
- */
- if (sched_mc_power_savings < POWERSAVINGS_BALANCE_WAKEUP)
- return 0;
- }
-
- return unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2);
-}
-
-static int active_load_balance_cpu_stop(void *data);
-
-/*
- * Check this_cpu to ensure it is balanced within domain. Attempt to move
- * tasks if there is an imbalance.
- */
-static int load_balance(int this_cpu, struct rq *this_rq,
- struct sched_domain *sd, enum cpu_idle_type idle,
- int *balance)
-{
- int ld_moved, all_pinned = 0, active_balance = 0;
- struct sched_group *group;
- unsigned long imbalance;
- struct rq *busiest;
- unsigned long flags;
- struct cpumask *cpus = __get_cpu_var(load_balance_tmpmask);
-
- cpumask_copy(cpus, cpu_active_mask);
-
- schedstat_inc(sd, lb_count[idle]);
-
-redo:
- group = find_busiest_group(sd, this_cpu, &imbalance, idle,
- cpus, balance);
-
- if (*balance == 0)
- goto out_balanced;
-
- if (!group) {
- schedstat_inc(sd, lb_nobusyg[idle]);
- goto out_balanced;
- }
-
- busiest = find_busiest_queue(sd, group, idle, imbalance, cpus);
- if (!busiest) {
- schedstat_inc(sd, lb_nobusyq[idle]);
- goto out_balanced;
- }
-
- BUG_ON(busiest == this_rq);
-
- schedstat_add(sd, lb_imbalance[idle], imbalance);
-
- ld_moved = 0;
- if (busiest->nr_running > 1) {
- /*
- * Attempt to move tasks. If find_busiest_group has found
- * an imbalance but busiest->nr_running <= 1, the group is
- * still unbalanced. ld_moved simply stays zero, so it is
- * correctly treated as an imbalance.
- */
- all_pinned = 1;
- local_irq_save(flags);
- double_rq_lock(this_rq, busiest);
- ld_moved = move_tasks(this_rq, this_cpu, busiest,
- imbalance, sd, idle, &all_pinned);
- double_rq_unlock(this_rq, busiest);
- local_irq_restore(flags);
-
- /*
- * some other cpu did the load balance for us.
- */
- if (ld_moved && this_cpu != smp_processor_id())
- resched_cpu(this_cpu);
-
- /* All tasks on this runqueue were pinned by CPU affinity */
- if (unlikely(all_pinned)) {
- cpumask_clear_cpu(cpu_of(busiest), cpus);
- if (!cpumask_empty(cpus))
- goto redo;
- goto out_balanced;
- }
- }
-
- if (!ld_moved) {
- schedstat_inc(sd, lb_failed[idle]);
- /*
- * Increment the failure counter only on periodic balance.
- * We do not want newidle balance, which can be very
- * frequent, pollute the failure counter causing
- * excessive cache_hot migrations and active balances.
- */
- if (idle != CPU_NEWLY_IDLE)
- sd->nr_balance_failed++;
-
- if (need_active_balance(sd, idle, cpu_of(busiest), this_cpu)) {
- raw_spin_lock_irqsave(&busiest->lock, flags);
-
- /* don't kick the active_load_balance_cpu_stop,
- * if the curr task on busiest cpu can't be
- * moved to this_cpu
- */
- if (!cpumask_test_cpu(this_cpu,
- tsk_cpus_allowed(busiest->curr))) {
- raw_spin_unlock_irqrestore(&busiest->lock,
- flags);
- all_pinned = 1;
- goto out_one_pinned;
- }
-
- /*
- * ->active_balance synchronizes accesses to
- * ->active_balance_work. Once set, it's cleared
- * only after active load balance is finished.
- */
- if (!busiest->active_balance) {
- busiest->active_balance = 1;
- busiest->push_cpu = this_cpu;
- active_balance = 1;
- }
- raw_spin_unlock_irqrestore(&busiest->lock, flags);
-
- if (active_balance)
- stop_one_cpu_nowait(cpu_of(busiest),
- active_load_balance_cpu_stop, busiest,
- &busiest->active_balance_work);
-
- /*
- * We've kicked active balancing, reset the failure
- * counter.
- */
- sd->nr_balance_failed = sd->cache_nice_tries+1;
- }
- } else
- sd->nr_balance_failed = 0;
-
- if (likely(!active_balance)) {
- /* We were unbalanced, so reset the balancing interval */
- sd->balance_interval = sd->min_interval;
- } else {
- /*
- * If we've begun active balancing, start to back off. This
- * case may not be covered by the all_pinned logic if there
- * is only 1 task on the busy runqueue (because we don't call
- * move_tasks).
- */
- if (sd->balance_interval < sd->max_interval)
- sd->balance_interval *= 2;
- }
-
- goto out;
-
-out_balanced:
- schedstat_inc(sd, lb_balanced[idle]);
-
- sd->nr_balance_failed = 0;
-
-out_one_pinned:
- /* tune up the balancing interval */
- if ((all_pinned && sd->balance_interval < MAX_PINNED_INTERVAL) ||
- (sd->balance_interval < sd->max_interval))
- sd->balance_interval *= 2;
-
- ld_moved = 0;
-out:
- return ld_moved;
-}
-
-/*
- * idle_balance is called by schedule() if this_cpu is about to become
- * idle. Attempts to pull tasks from other CPUs.
- */
-void idle_balance(int this_cpu, struct rq *this_rq)
-{
- struct sched_domain *sd;
- int pulled_task = 0;
- unsigned long next_balance = jiffies + HZ;
-
- this_rq->idle_stamp = this_rq->clock;
-
- if (this_rq->avg_idle < sysctl_sched_migration_cost)
- return;
-
- /*
- * Drop the rq->lock, but keep IRQ/preempt disabled.
- */
- raw_spin_unlock(&this_rq->lock);
-
- update_shares(this_cpu);
- rcu_read_lock();
- for_each_domain(this_cpu, sd) {
- unsigned long interval;
- int balance = 1;
-
- if (!(sd->flags & SD_LOAD_BALANCE))
- continue;
-
- if (sd->flags & SD_BALANCE_NEWIDLE) {
- /* If we've pulled tasks over stop searching: */
- pulled_task = load_balance(this_cpu, this_rq,
- sd, CPU_NEWLY_IDLE, &balance);
- }
-
- interval = msecs_to_jiffies(sd->balance_interval);
- if (time_after(next_balance, sd->last_balance + interval))
- next_balance = sd->last_balance + interval;
- if (pulled_task) {
- this_rq->idle_stamp = 0;
- break;
- }
- }
- rcu_read_unlock();
-
- raw_spin_lock(&this_rq->lock);
-
- if (pulled_task || time_after(jiffies, this_rq->next_balance)) {
- /*
- * We are going idle. next_balance may be set based on
- * a busy processor. So reset next_balance.
- */
- this_rq->next_balance = next_balance;
- }
-}
-
-/*
- * active_load_balance_cpu_stop is run by cpu stopper. It pushes
- * running tasks off the busiest CPU onto idle CPUs. It requires at
- * least 1 task to be running on each physical CPU where possible, and
- * avoids physical / logical imbalances.
- */
-static int active_load_balance_cpu_stop(void *data)
-{
- struct rq *busiest_rq = data;
- int busiest_cpu = cpu_of(busiest_rq);
- int target_cpu = busiest_rq->push_cpu;
- struct rq *target_rq = cpu_rq(target_cpu);
- struct sched_domain *sd;
-
- raw_spin_lock_irq(&busiest_rq->lock);
-
- /* make sure the requested cpu hasn't gone down in the meantime */
- if (unlikely(busiest_cpu != smp_processor_id() ||
- !busiest_rq->active_balance))
- goto out_unlock;
-
- /* Is there any task to move? */
- if (busiest_rq->nr_running <= 1)
- goto out_unlock;
-
- /*
- * This condition is "impossible", if it occurs
- * we need to fix it. Originally reported by
- * Bjorn Helgaas on a 128-cpu setup.
- */
- BUG_ON(busiest_rq == target_rq);
-
- /* move a task from busiest_rq to target_rq */
- double_lock_balance(busiest_rq, target_rq);
-
- /* Search for an sd spanning us and the target CPU. */
- rcu_read_lock();
- for_each_domain(target_cpu, sd) {
- if ((sd->flags & SD_LOAD_BALANCE) &&
- cpumask_test_cpu(busiest_cpu, sched_domain_span(sd)))
- break;
- }
-
- if (likely(sd)) {
- schedstat_inc(sd, alb_count);
-
- if (move_one_task(target_rq, target_cpu, busiest_rq,
- sd, CPU_IDLE))
- schedstat_inc(sd, alb_pushed);
- else
- schedstat_inc(sd, alb_failed);
- }
- rcu_read_unlock();
- double_unlock_balance(busiest_rq, target_rq);
-out_unlock:
- busiest_rq->active_balance = 0;
- raw_spin_unlock_irq(&busiest_rq->lock);
- return 0;
-}
-
-#ifdef CONFIG_NO_HZ
-/*
- * idle load balancing details
- * - One of the idle CPUs nominates itself as idle load_balancer, while
- * entering idle.
- * - This idle load balancer CPU will also go into tickless mode when
- * it is idle, just like all other idle CPUs
- * - When one of the busy CPUs notice that there may be an idle rebalancing
- * needed, they will kick the idle load balancer, which then does idle
- * load balancing for all the idle CPUs.
- */
-static struct {
- atomic_t load_balancer;
- atomic_t first_pick_cpu;
- atomic_t second_pick_cpu;
- cpumask_var_t idle_cpus_mask;
- cpumask_var_t grp_idle_mask;
- unsigned long next_balance; /* in jiffy units */
-} nohz ____cacheline_aligned;
-
-int get_nohz_load_balancer(void)
-{
- return atomic_read(&nohz.load_balancer);
-}
-
-#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->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)
-
-/**
- * is_semi_idle_group - Checks if the given sched_group is semi-idle.
- * @ilb_group: group to be checked for semi-idleness
- *
- * Returns: 1 if the group is semi-idle. 0 otherwise.
- *
- * We define a sched_group to be semi idle if it has atleast one idle-CPU
- * and atleast one non-idle CPU. This helper function checks if the given
- * sched_group is semi-idle or not.
- */
-static inline int is_semi_idle_group(struct sched_group *ilb_group)
-{
- cpumask_and(nohz.grp_idle_mask, nohz.idle_cpus_mask,
- sched_group_cpus(ilb_group));
-
- /*
- * A sched_group is semi-idle when it has atleast one busy cpu
- * and atleast one idle cpu.
- */
- if (cpumask_empty(nohz.grp_idle_mask))
- return 0;
-
- if (cpumask_equal(nohz.grp_idle_mask, sched_group_cpus(ilb_group)))
- return 0;
-
- return 1;
-}
-/**
- * find_new_ilb - Finds the optimum idle load balancer for nomination.
- * @cpu: The cpu which is nominating a new idle_load_balancer.
- *
- * Returns: Returns the id of the idle load balancer if it exists,
- * Else, returns >= nr_cpu_ids.
- *
- * This algorithm picks the idle load balancer such that it belongs to a
- * semi-idle powersavings sched_domain. The idea is to try and avoid
- * completely idle packages/cores just for the purpose of idle load balancing
- * when there are other idle cpu's which are better suited for that job.
- */
-static int find_new_ilb(int cpu)
-{
- struct sched_domain *sd;
- struct sched_group *ilb_group;
- int ilb = nr_cpu_ids;
-
- /*
- * Have idle load balancer selection from semi-idle packages only
- * when power-aware load balancing is enabled
- */
- if (!(sched_smt_power_savings || sched_mc_power_savings))
- goto out_done;
-
- /*
- * Optimize for the case when we have no idle CPUs or only one
- * idle CPU. Don't walk the sched_domain hierarchy in such cases
- */
- if (cpumask_weight(nohz.idle_cpus_mask) < 2)
- goto out_done;
-
- rcu_read_lock();
- for_each_flag_domain(cpu, sd, SD_POWERSAVINGS_BALANCE) {
- ilb_group = sd->groups;
-
- do {
- if (is_semi_idle_group(ilb_group)) {
- ilb = cpumask_first(nohz.grp_idle_mask);
- goto unlock;
- }
-
- ilb_group = ilb_group->next;
-
- } while (ilb_group != sd->groups);
- }
-unlock:
- rcu_read_unlock();
-
-out_done:
- return ilb;
-}
-#else /* (CONFIG_SCHED_MC || CONFIG_SCHED_SMT) */
-static inline int find_new_ilb(int call_cpu)
-{
- return nr_cpu_ids;
-}
-#endif
-
-/*
- * Kick a CPU to do the nohz balancing, if it is time for it. We pick the
- * nohz_load_balancer CPU (if there is one) otherwise fallback to any idle
- * CPU (if there is one).
- */
-static void nohz_balancer_kick(int cpu)
-{
- int ilb_cpu;
-
- nohz.next_balance++;
-
- ilb_cpu = get_nohz_load_balancer();
-
- if (ilb_cpu >= nr_cpu_ids) {
- ilb_cpu = cpumask_first(nohz.idle_cpus_mask);
- if (ilb_cpu >= nr_cpu_ids)
- return;
- }
-
- if (!cpu_rq(ilb_cpu)->nohz_balance_kick) {
- cpu_rq(ilb_cpu)->nohz_balance_kick = 1;
-
- smp_mb();
- /*
- * Use smp_send_reschedule() instead of resched_cpu().
- * This way we generate a sched IPI on the target cpu which
- * is idle. And the softirq performing nohz idle load balance
- * will be run before returning from the IPI.
- */
- smp_send_reschedule(ilb_cpu);
- }
- return;
-}
-
-/*
- * This routine will try to nominate the ilb (idle load balancing)
- * owner among the cpus whose ticks are stopped. ilb owner will do the idle
- * load balancing on behalf of all those cpus.
- *
- * When the ilb owner becomes busy, we will not have new ilb owner until some
- * idle CPU wakes up and goes back to idle or some busy CPU tries to kick
- * idle load balancing by kicking one of the idle CPUs.
- *
- * Ticks are stopped for the ilb owner as well, with busy CPU kicking this
- * ilb owner CPU in future (when there is a need for idle load balancing on
- * behalf of all idle CPUs).
- */
-void select_nohz_load_balancer(int stop_tick)
-{
- int cpu = smp_processor_id();
-
- if (stop_tick) {
- if (!cpu_active(cpu)) {
- if (atomic_read(&nohz.load_balancer) != cpu)
- return;
-
- /*
- * If we are going offline and still the leader,
- * give up!
- */
- if (atomic_cmpxchg(&nohz.load_balancer, cpu,
- nr_cpu_ids) != cpu)
- BUG();
-
- return;
- }
-
- cpumask_set_cpu(cpu, nohz.idle_cpus_mask);
-
- if (atomic_read(&nohz.first_pick_cpu) == cpu)
- atomic_cmpxchg(&nohz.first_pick_cpu, cpu, nr_cpu_ids);
- if (atomic_read(&nohz.second_pick_cpu) == cpu)
- atomic_cmpxchg(&nohz.second_pick_cpu, cpu, nr_cpu_ids);
-
- if (atomic_read(&nohz.load_balancer) >= nr_cpu_ids) {
- int new_ilb;
-
- /* make me the ilb owner */
- if (atomic_cmpxchg(&nohz.load_balancer, nr_cpu_ids,
- cpu) != nr_cpu_ids)
- return;
-
- /*
- * Check to see if there is a more power-efficient
- * ilb.
- */
- new_ilb = find_new_ilb(cpu);
- if (new_ilb < nr_cpu_ids && new_ilb != cpu) {
- atomic_set(&nohz.load_balancer, nr_cpu_ids);
- resched_cpu(new_ilb);
- return;
- }
- return;
- }
- } else {
- if (!cpumask_test_cpu(cpu, nohz.idle_cpus_mask))
- return;
-
- cpumask_clear_cpu(cpu, nohz.idle_cpus_mask);
-
- if (atomic_read(&nohz.load_balancer) == cpu)
- if (atomic_cmpxchg(&nohz.load_balancer, cpu,
- nr_cpu_ids) != cpu)
- BUG();
- }
- return;
-}
-#endif
-
-static DEFINE_SPINLOCK(balancing);
-
-static unsigned long __read_mostly max_load_balance_interval = HZ/10;
-
-/*
- * Scale the max load_balance interval with the number of CPUs in the system.
- * This trades load-balance latency on larger machines for less cross talk.
- */
-void update_max_interval(void)
-{
- max_load_balance_interval = HZ*num_online_cpus()/10;
-}
-
-/*
- * It checks each scheduling domain to see if it is due to be balanced,
- * and initiates a balancing operation if so.
- *
- * Balancing parameters are set up in arch_init_sched_domains.
- */
-static void rebalance_domains(int cpu, enum cpu_idle_type idle)
-{
- int balance = 1;
- struct rq *rq = cpu_rq(cpu);
- unsigned long interval;
- struct sched_domain *sd;
- /* Earliest time when we have to do rebalance again */
- unsigned long next_balance = jiffies + 60*HZ;
- int update_next_balance = 0;
- int need_serialize;
-
- update_shares(cpu);
-
- rcu_read_lock();
- for_each_domain(cpu, sd) {
- if (!(sd->flags & SD_LOAD_BALANCE))
- continue;
-
- interval = sd->balance_interval;
- if (idle != CPU_IDLE)
- interval *= sd->busy_factor;
-
- /* scale ms to jiffies */
- interval = msecs_to_jiffies(interval);
- interval = clamp(interval, 1UL, max_load_balance_interval);
-
- need_serialize = sd->flags & SD_SERIALIZE;
-
- if (need_serialize) {
- if (!spin_trylock(&balancing))
- goto out;
- }
-
- if (time_after_eq(jiffies, sd->last_balance + interval)) {
- if (load_balance(cpu, rq, sd, idle, &balance)) {
- /*
- * We've pulled tasks over so either we're no
- * longer idle.
- */
- idle = CPU_NOT_IDLE;
- }
- sd->last_balance = jiffies;
- }
- if (need_serialize)
- spin_unlock(&balancing);
-out:
- if (time_after(next_balance, sd->last_balance + interval)) {
- next_balance = sd->last_balance + interval;
- update_next_balance = 1;
- }
-
- /*
- * Stop the load balance at this level. There is another
- * CPU in our sched group which is doing load balancing more
- * actively.
- */
- if (!balance)
- break;
- }
- rcu_read_unlock();
-
- /*
- * next_balance will be updated only when there is a need.
- * When the cpu is attached to null domain for ex, it will not be
- * updated.
- */
- if (likely(update_next_balance))
- rq->next_balance = next_balance;
-}
-
-#ifdef CONFIG_NO_HZ
-/*
- * In CONFIG_NO_HZ case, the idle balance kickee will do the
- * rebalancing for all the cpus for whom scheduler ticks are stopped.
- */
-static void nohz_idle_balance(int this_cpu, enum cpu_idle_type idle)
-{
- struct rq *this_rq = cpu_rq(this_cpu);
- struct rq *rq;
- int balance_cpu;
-
- if (idle != CPU_IDLE || !this_rq->nohz_balance_kick)
- return;
-
- for_each_cpu(balance_cpu, nohz.idle_cpus_mask) {
- if (balance_cpu == this_cpu)
- continue;
-
- /*
- * If this cpu gets work to do, stop the load balancing
- * work being done for other cpus. Next load
- * balancing owner will pick it up.
- */
- if (need_resched()) {
- this_rq->nohz_balance_kick = 0;
- break;
- }
-
- raw_spin_lock_irq(&this_rq->lock);
- update_rq_clock(this_rq);
- update_cpu_load(this_rq);
- raw_spin_unlock_irq(&this_rq->lock);
-
- rebalance_domains(balance_cpu, CPU_IDLE);
-
- rq = cpu_rq(balance_cpu);
- if (time_after(this_rq->next_balance, rq->next_balance))
- this_rq->next_balance = rq->next_balance;
- }
- nohz.next_balance = this_rq->next_balance;
- this_rq->nohz_balance_kick = 0;
-}
-
-/*
- * Current heuristic for kicking the idle load balancer
- * - first_pick_cpu is the one of the busy CPUs. It will kick
- * idle load balancer when it has more than one process active. This
- * eliminates the need for idle load balancing altogether when we have
- * only one running process in the system (common case).
- * - If there are more than one busy CPU, idle load balancer may have
- * to run for active_load_balance to happen (i.e., two busy CPUs are
- * SMT or core siblings and can run better if they move to different
- * physical CPUs). So, second_pick_cpu is the second of the busy CPUs
- * which will kick idle load balancer as soon as it has any load.
- */
-static inline int nohz_kick_needed(struct rq *rq, int cpu)
-{
- unsigned long now = jiffies;
- int ret;
- int first_pick_cpu, second_pick_cpu;
-
- if (time_before(now, nohz.next_balance))
- return 0;
-
- if (idle_cpu(cpu))
- return 0;
-
- first_pick_cpu = atomic_read(&nohz.first_pick_cpu);
- second_pick_cpu = atomic_read(&nohz.second_pick_cpu);
-
- if (first_pick_cpu < nr_cpu_ids && first_pick_cpu != cpu &&
- second_pick_cpu < nr_cpu_ids && second_pick_cpu != cpu)
- return 0;
-
- ret = atomic_cmpxchg(&nohz.first_pick_cpu, nr_cpu_ids, cpu);
- if (ret == nr_cpu_ids || ret == cpu) {
- atomic_cmpxchg(&nohz.second_pick_cpu, cpu, nr_cpu_ids);
- if (rq->nr_running > 1)
- return 1;
- } else {
- ret = atomic_cmpxchg(&nohz.second_pick_cpu, nr_cpu_ids, cpu);
- if (ret == nr_cpu_ids || ret == cpu) {
- if (rq->nr_running)
- return 1;
- }
- }
- return 0;
-}
-#else
-static void nohz_idle_balance(int this_cpu, enum cpu_idle_type idle) { }
-#endif
-
-/*
- * run_rebalance_domains is triggered when needed from the scheduler tick.
- * Also triggered for nohz idle balancing (with nohz_balancing_kick set).
- */
-static void run_rebalance_domains(struct softirq_action *h)
-{
- int this_cpu = smp_processor_id();
- struct rq *this_rq = cpu_rq(this_cpu);
- enum cpu_idle_type idle = this_rq->idle_balance ?
- CPU_IDLE : CPU_NOT_IDLE;
-
- rebalance_domains(this_cpu, idle);
-
- /*
- * If this cpu has a pending nohz_balance_kick, then do the
- * balancing on behalf of the other idle cpus whose ticks are
- * stopped.
- */
- nohz_idle_balance(this_cpu, idle);
-}
-
-static inline int on_null_domain(int cpu)
-{
- return !rcu_dereference_sched(cpu_rq(cpu)->sd);
-}
-
-/*
- * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing.
- */
-void trigger_load_balance(struct rq *rq, int cpu)
-{
- /* Don't need to rebalance while attached to NULL domain */
- if (time_after_eq(jiffies, rq->next_balance) &&
- likely(!on_null_domain(cpu)))
- raise_softirq(SCHED_SOFTIRQ);
-#ifdef CONFIG_NO_HZ
- else if (nohz_kick_needed(rq, cpu) && likely(!on_null_domain(cpu)))
- nohz_balancer_kick(cpu);
-#endif
-}
-
-static void rq_online_fair(struct rq *rq)
-{
- update_sysctl();
-}
-
-static void rq_offline_fair(struct rq *rq)
-{
- update_sysctl();
-}
-
-#endif /* CONFIG_SMP */
-
-/*
- * scheduler tick hitting a task of our scheduling class:
- */
-static void task_tick_fair(struct rq *rq, struct task_struct *curr, int queued)
-{
- struct cfs_rq *cfs_rq;
- struct sched_entity *se = &curr->se;
-
- for_each_sched_entity(se) {
- cfs_rq = cfs_rq_of(se);
- entity_tick(cfs_rq, se, queued);
- }
-}
-
-/*
- * called on fork with the child task as argument from the parent's context
- * - child not yet on the tasklist
- * - preemption disabled
- */
-static void task_fork_fair(struct task_struct *p)
-{
- struct cfs_rq *cfs_rq = task_cfs_rq(current);
- struct sched_entity *se = &p->se, *curr = cfs_rq->curr;
- int this_cpu = smp_processor_id();
- struct rq *rq = this_rq();
- unsigned long flags;
-
- raw_spin_lock_irqsave(&rq->lock, flags);
-
- update_rq_clock(rq);
-
- if (unlikely(task_cpu(p) != this_cpu)) {
- rcu_read_lock();
- __set_task_cpu(p, this_cpu);
- rcu_read_unlock();
- }
-
- update_curr(cfs_rq);
-
- if (curr)
- se->vruntime = curr->vruntime;
- place_entity(cfs_rq, se, 1);
-
- if (sysctl_sched_child_runs_first && curr && entity_before(curr, se)) {
- /*
- * Upon rescheduling, sched_class::put_prev_task() will place
- * 'current' within the tree based on its new key value.
- */
- swap(curr->vruntime, se->vruntime);
- resched_task(rq->curr);
- }
-
- se->vruntime -= cfs_rq->min_vruntime;
-
- raw_spin_unlock_irqrestore(&rq->lock, flags);
-}
-
-/*
- * Priority of the task has changed. Check to see if we preempt
- * the current task.
- */
-static void
-prio_changed_fair(struct rq *rq, struct task_struct *p, int oldprio)
-{
- if (!p->se.on_rq)
- return;
-
- /*
- * Reschedule if we are currently running on this runqueue and
- * our priority decreased, or if we are not currently running on
- * this runqueue and our priority is higher than the current's
- */
- if (rq->curr == p) {
- if (p->prio > oldprio)
- resched_task(rq->curr);
- } else
- check_preempt_curr(rq, p, 0);
-}
-
-static void switched_from_fair(struct rq *rq, struct task_struct *p)
-{
- struct sched_entity *se = &p->se;
- struct cfs_rq *cfs_rq = cfs_rq_of(se);
-
- /*
- * Ensure the task's vruntime is normalized, so that when its
- * switched back to the fair class the enqueue_entity(.flags=0) will
- * do the right thing.
- *
- * If it was on_rq, then the dequeue_entity(.flags=0) will already
- * have normalized the vruntime, if it was !on_rq, then only when
- * the task is sleeping will it still have non-normalized vruntime.
- */
- if (!se->on_rq && p->state != TASK_RUNNING) {
- /*
- * Fix up our vruntime so that the current sleep doesn't
- * cause 'unlimited' sleep bonus.
- */
- place_entity(cfs_rq, se, 0);
- se->vruntime -= cfs_rq->min_vruntime;
- }
-}
-
-/*
- * We switched to the sched_fair class.
- */
-static void switched_to_fair(struct rq *rq, struct task_struct *p)
-{
- if (!p->se.on_rq)
- return;
-
- /*
- * We were most likely switched from sched_rt, so
- * kick off the schedule if running, otherwise just see
- * if we can still preempt the current task.
- */
- if (rq->curr == p)
- resched_task(rq->curr);
- else
- check_preempt_curr(rq, p, 0);
-}
-
-/* Account for a task changing its policy or group.
- *
- * This routine is mostly called to set cfs_rq->curr field when a task
- * migrates between groups/classes.
- */
-static void set_curr_task_fair(struct rq *rq)
-{
- struct sched_entity *se = &rq->curr->se;
-
- for_each_sched_entity(se) {
- struct cfs_rq *cfs_rq = cfs_rq_of(se);
-
- set_next_entity(cfs_rq, se);
- /* ensure bandwidth has been allocated on our new cfs_rq */
- account_cfs_rq_runtime(cfs_rq, 0);
- }
-}
-
-void init_cfs_rq(struct cfs_rq *cfs_rq)
-{
- cfs_rq->tasks_timeline = RB_ROOT;
- INIT_LIST_HEAD(&cfs_rq->tasks);
- cfs_rq->min_vruntime = (u64)(-(1LL << 20));
-#ifndef CONFIG_64BIT
- cfs_rq->min_vruntime_copy = cfs_rq->min_vruntime;
-#endif
-}
-
-#ifdef CONFIG_FAIR_GROUP_SCHED
-static void task_move_group_fair(struct task_struct *p, int on_rq)
-{
- /*
- * If the task was not on the rq at the time of this cgroup movement
- * it must have been asleep, sleeping tasks keep their ->vruntime
- * absolute on their old rq until wakeup (needed for the fair sleeper
- * bonus in place_entity()).
- *
- * If it was on the rq, we've just 'preempted' it, which does convert
- * ->vruntime to a relative base.
- *
- * Make sure both cases convert their relative position when migrating
- * to another cgroup's rq. This does somewhat interfere with the
- * fair sleeper stuff for the first placement, but who cares.
- */
- if (!on_rq)
- p->se.vruntime -= cfs_rq_of(&p->se)->min_vruntime;
- set_task_rq(p, task_cpu(p));
- if (!on_rq)
- p->se.vruntime += cfs_rq_of(&p->se)->min_vruntime;
-}
-
-void free_fair_sched_group(struct task_group *tg)
-{
- int i;
-
- destroy_cfs_bandwidth(tg_cfs_bandwidth(tg));
-
- for_each_possible_cpu(i) {
- if (tg->cfs_rq)
- kfree(tg->cfs_rq[i]);
- if (tg->se)
- kfree(tg->se[i]);
- }
-
- kfree(tg->cfs_rq);
- kfree(tg->se);
-}
-
-int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
-{
- struct cfs_rq *cfs_rq;
- struct sched_entity *se;
- int i;
-
- tg->cfs_rq = kzalloc(sizeof(cfs_rq) * nr_cpu_ids, GFP_KERNEL);
- if (!tg->cfs_rq)
- goto err;
- tg->se = kzalloc(sizeof(se) * nr_cpu_ids, GFP_KERNEL);
- if (!tg->se)
- goto err;
-
- tg->shares = NICE_0_LOAD;
-
- init_cfs_bandwidth(tg_cfs_bandwidth(tg));
-
- for_each_possible_cpu(i) {
- cfs_rq = kzalloc_node(sizeof(struct cfs_rq),
- GFP_KERNEL, cpu_to_node(i));
- if (!cfs_rq)
- goto err;
-
- se = kzalloc_node(sizeof(struct sched_entity),
- GFP_KERNEL, cpu_to_node(i));
- if (!se)
- goto err_free_rq;
-
- init_cfs_rq(cfs_rq);
- init_tg_cfs_entry(tg, cfs_rq, se, i, parent->se[i]);
- }
-
- return 1;
-
-err_free_rq:
- kfree(cfs_rq);
-err:
- return 0;
-}
-
-void unregister_fair_sched_group(struct task_group *tg, int cpu)
-{
- struct rq *rq = cpu_rq(cpu);
- unsigned long flags;
-
- /*
- * Only empty task groups can be destroyed; so we can speculatively
- * check on_list without danger of it being re-added.
- */
- if (!tg->cfs_rq[cpu]->on_list)
- return;
-
- raw_spin_lock_irqsave(&rq->lock, flags);
- list_del_leaf_cfs_rq(tg->cfs_rq[cpu]);
- raw_spin_unlock_irqrestore(&rq->lock, flags);
-}
-
-void init_tg_cfs_entry(struct task_group *tg, struct cfs_rq *cfs_rq,
- struct sched_entity *se, int cpu,
- struct sched_entity *parent)
-{
- struct rq *rq = cpu_rq(cpu);
-
- cfs_rq->tg = tg;
- cfs_rq->rq = rq;
-#ifdef CONFIG_SMP
- /* allow initial update_cfs_load() to truncate */
- cfs_rq->load_stamp = 1;
-#endif
- init_cfs_rq_runtime(cfs_rq);
-
- tg->cfs_rq[cpu] = cfs_rq;
- tg->se[cpu] = se;
-
- /* se could be NULL for root_task_group */
- if (!se)
- return;
-
- if (!parent)
- se->cfs_rq = &rq->cfs;
- else
- se->cfs_rq = parent->my_q;
-
- se->my_q = cfs_rq;
- update_load_set(&se->load, 0);
- se->parent = parent;
-}
-
-static DEFINE_MUTEX(shares_mutex);
-
-int sched_group_set_shares(struct task_group *tg, unsigned long shares)
-{
- int i;
- unsigned long flags;
-
- /*
- * We can't change the weight of the root cgroup.
- */
- if (!tg->se[0])
- return -EINVAL;
-
- shares = clamp(shares, scale_load(MIN_SHARES), scale_load(MAX_SHARES));
-
- mutex_lock(&shares_mutex);
- if (tg->shares == shares)
- goto done;
-
- tg->shares = shares;
- for_each_possible_cpu(i) {
- struct rq *rq = cpu_rq(i);
- struct sched_entity *se;
-
- se = tg->se[i];
- /* Propagate contribution to hierarchy */
- raw_spin_lock_irqsave(&rq->lock, flags);
- for_each_sched_entity(se)
- update_cfs_shares(group_cfs_rq(se));
- raw_spin_unlock_irqrestore(&rq->lock, flags);
- }
-
-done:
- mutex_unlock(&shares_mutex);
- return 0;
-}
-#else /* CONFIG_FAIR_GROUP_SCHED */
-
-void free_fair_sched_group(struct task_group *tg) { }
-
-int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
-{
- return 1;
-}
-
-void unregister_fair_sched_group(struct task_group *tg, int cpu) { }
-
-#endif /* CONFIG_FAIR_GROUP_SCHED */
-
-
-static unsigned int get_rr_interval_fair(struct rq *rq, struct task_struct *task)
-{
- struct sched_entity *se = &task->se;
- unsigned int rr_interval = 0;
-
- /*
- * Time slice is 0 for SCHED_OTHER tasks that are on an otherwise
- * idle runqueue:
- */
- if (rq->cfs.load.weight)
- rr_interval = NS_TO_JIFFIES(sched_slice(&rq->cfs, se));
-
- return rr_interval;
-}
-
-/*
- * All the scheduling class methods:
- */
-const struct sched_class fair_sched_class = {
- .next = &idle_sched_class,
- .enqueue_task = enqueue_task_fair,
- .dequeue_task = dequeue_task_fair,
- .yield_task = yield_task_fair,
- .yield_to_task = yield_to_task_fair,
-
- .check_preempt_curr = check_preempt_wakeup,
-
- .pick_next_task = pick_next_task_fair,
- .put_prev_task = put_prev_task_fair,
-
-#ifdef CONFIG_SMP
- .select_task_rq = select_task_rq_fair,
-
- .rq_online = rq_online_fair,
- .rq_offline = rq_offline_fair,
-
- .task_waking = task_waking_fair,
-#endif
-
- .set_curr_task = set_curr_task_fair,
- .task_tick = task_tick_fair,
- .task_fork = task_fork_fair,
-
- .prio_changed = prio_changed_fair,
- .switched_from = switched_from_fair,
- .switched_to = switched_to_fair,
-
- .get_rr_interval = get_rr_interval_fair,
-
-#ifdef CONFIG_FAIR_GROUP_SCHED
- .task_move_group = task_move_group_fair,
-#endif
-};
-
-#ifdef CONFIG_SCHED_DEBUG
-void print_cfs_stats(struct seq_file *m, int cpu)
-{
- struct cfs_rq *cfs_rq;
-
- rcu_read_lock();
- for_each_leaf_cfs_rq(cpu_rq(cpu), cfs_rq)
- print_cfs_rq(m, cpu, cfs_rq);
- rcu_read_unlock();
-}
-#endif
-
-__init void init_sched_fair_class(void)
-{
-#ifdef CONFIG_SMP
- open_softirq(SCHED_SOFTIRQ, run_rebalance_domains);
-
-#ifdef CONFIG_NO_HZ
- zalloc_cpumask_var(&nohz.idle_cpus_mask, GFP_NOWAIT);
- alloc_cpumask_var(&nohz.grp_idle_mask, GFP_NOWAIT);
- atomic_set(&nohz.load_balancer, nr_cpu_ids);
- atomic_set(&nohz.first_pick_cpu, nr_cpu_ids);
- atomic_set(&nohz.second_pick_cpu, nr_cpu_ids);
-#endif
-#endif /* SMP */
-
-}