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-rw-r--r--kernel/sched_fair.c1829
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diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
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index ba7fd6e9556..00000000000
--- a/kernel/sched_fair.c
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-/*
- * 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>
-
-/*
- * Targeted preemption latency for CPU-bound tasks:
- * (default: 20ms * (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 = 20000000ULL;
-
-/*
- * Minimal preemption granularity for CPU-bound tasks:
- * (default: 4 msec * (1 + ilog(ncpus)), units: nanoseconds)
- */
-unsigned int sysctl_sched_min_granularity = 4000000ULL;
-
-/*
- * is kept at sysctl_sched_latency / sysctl_sched_min_granularity
- */
-static unsigned int sched_nr_latency = 5;
-
-/*
- * After fork, child runs first. (default) If set to 0 then
- * parent will (try to) run first.
- */
-const_debug unsigned int sysctl_sched_child_runs_first = 1;
-
-/*
- * sys_sched_yield() compat mode
- *
- * This option switches the agressive yield implementation of the
- * old scheduler back on.
- */
-unsigned int __read_mostly sysctl_sched_compat_yield;
-
-/*
- * SCHED_OTHER wake-up granularity.
- * (default: 5 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 = 5000000UL;
-
-const_debug unsigned int sysctl_sched_migration_cost = 500000UL;
-
-static const struct sched_class fair_sched_class;
-
-/**************************************************************
- * CFS operations on generic schedulable entities:
- */
-
-static inline struct task_struct *task_of(struct sched_entity *se)
-{
- return container_of(se, struct task_struct, se);
-}
-
-#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)
-
-/* 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;
-}
-
-/* Given a group's cfs_rq on one cpu, return its corresponding cfs_rq on
- * another cpu ('this_cpu')
- */
-static inline struct cfs_rq *cpu_cfs_rq(struct cfs_rq *cfs_rq, int this_cpu)
-{
- return cfs_rq->tg->cfs_rq[this_cpu];
-}
-
-/* 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 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 struct cfs_rq *cpu_cfs_rq(struct cfs_rq *cfs_rq, int this_cpu)
-{
- return &cpu_rq(this_cpu)->cfs;
-}
-
-#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 */
-
-
-/**************************************************************
- * 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 s64 entity_key(struct cfs_rq *cfs_rq, struct sched_entity *se)
-{
- return se->vruntime - cfs_rq->min_vruntime;
-}
-
-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);
-}
-
-/*
- * 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;
- s64 key = entity_key(cfs_rq, se);
- 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 (key < entity_key(cfs_rq, 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);
-}
-
-static struct sched_entity *__pick_next_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_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:
- */
-
-#ifdef CONFIG_SCHED_DEBUG
-int sched_nr_latency_handler(struct ctl_table *table, int write,
- struct file *filp, void __user *buffer, size_t *lenp,
- loff_t *ppos)
-{
- int ret = proc_dointvec_minmax(table, write, filp, buffer, lenp, ppos);
-
- if (ret || !write)
- return ret;
-
- sched_nr_latency = DIV_ROUND_UP(sysctl_sched_latency,
- sysctl_sched_min_granularity);
-
- 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);
-}
-
-/*
- * 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->exec_max, max((u64)delta_exec, curr->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);
-}
-
-static void update_curr(struct cfs_rq *cfs_rq)
-{
- struct sched_entity *curr = cfs_rq->curr;
- u64 now = rq_of(cfs_rq)->clock;
- 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);
-
- cpuacct_charge(curtask, delta_exec);
- account_group_exec_runtime(curtask, delta_exec);
- }
-}
-
-static inline void
-update_stats_wait_start(struct cfs_rq *cfs_rq, struct sched_entity *se)
-{
- schedstat_set(se->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->wait_max, max(se->wait_max,
- rq_of(cfs_rq)->clock - se->wait_start));
- schedstat_set(se->wait_count, se->wait_count + 1);
- schedstat_set(se->wait_sum, se->wait_sum +
- rq_of(cfs_rq)->clock - se->wait_start);
- schedstat_set(se->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;
-}
-
-/**************************************************
- * 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))
- inc_cpu_load(rq_of(cfs_rq), 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++;
- se->on_rq = 1;
-}
-
-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))
- dec_cpu_load(rq_of(cfs_rq), 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--;
- se->on_rq = 0;
-}
-
-static void enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se)
-{
-#ifdef CONFIG_SCHEDSTATS
- if (se->sleep_start) {
- u64 delta = rq_of(cfs_rq)->clock - se->sleep_start;
- struct task_struct *tsk = task_of(se);
-
- if ((s64)delta < 0)
- delta = 0;
-
- if (unlikely(delta > se->sleep_max))
- se->sleep_max = delta;
-
- se->sleep_start = 0;
- se->sum_sleep_runtime += delta;
-
- account_scheduler_latency(tsk, delta >> 10, 1);
- }
- if (se->block_start) {
- u64 delta = rq_of(cfs_rq)->clock - se->block_start;
- struct task_struct *tsk = task_of(se);
-
- if ((s64)delta < 0)
- delta = 0;
-
- if (unlikely(delta > se->block_max))
- se->block_max = delta;
-
- se->block_start = 0;
- se->sum_sleep_runtime += 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);
-
- if (!initial) {
- /* sleeps upto a single latency don't count. */
- if (sched_feat(NEW_FAIR_SLEEPERS)) {
- unsigned long thresh = sysctl_sched_latency;
-
- /*
- * Convert the sleeper threshold into virtual time.
- * SCHED_IDLE is a special sub-class. We care about
- * fairness only relative to other SCHED_IDLE tasks,
- * all of which have the same weight.
- */
- if (sched_feat(NORMALIZED_SLEEPER) &&
- task_of(se)->policy != SCHED_IDLE)
- thresh = calc_delta_fair(thresh, se);
-
- vruntime -= thresh;
- }
-
- /* ensure we never gain time by being placed backwards. */
- vruntime = max_vruntime(se->vruntime, vruntime);
- }
-
- se->vruntime = vruntime;
-}
-
-static void
-enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int wakeup)
-{
- /*
- * Update run-time statistics of the 'current'.
- */
- update_curr(cfs_rq);
- account_entity_enqueue(cfs_rq, se);
-
- if (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);
-}
-
-static void __clear_buddies(struct cfs_rq *cfs_rq, struct sched_entity *se)
-{
- if (cfs_rq->last == se)
- cfs_rq->last = NULL;
-
- if (cfs_rq->next == se)
- cfs_rq->next = NULL;
-}
-
-static void clear_buddies(struct cfs_rq *cfs_rq, struct sched_entity *se)
-{
- for_each_sched_entity(se)
- __clear_buddies(cfs_rq_of(se), se);
-}
-
-static void
-dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int sleep)
-{
- /*
- * Update run-time statistics of the 'current'.
- */
- update_curr(cfs_rq);
-
- update_stats_dequeue(cfs_rq, se);
- if (sleep) {
-#ifdef CONFIG_SCHEDSTATS
- if (entity_is_task(se)) {
- struct task_struct *tsk = task_of(se);
-
- if (tsk->state & TASK_INTERRUPTIBLE)
- se->sleep_start = rq_of(cfs_rq)->clock;
- if (tsk->state & TASK_UNINTERRUPTIBLE)
- se->block_start = rq_of(cfs_rq)->clock;
- }
-#endif
- }
-
- clear_buddies(cfs_rq, se);
-
- if (se != cfs_rq->curr)
- __dequeue_entity(cfs_rq, se);
- account_entity_dequeue(cfs_rq, se);
- update_min_vruntime(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;
-
- 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);
- }
-}
-
-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->slice_max = max(se->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);
-
-static struct sched_entity *pick_next_entity(struct cfs_rq *cfs_rq)
-{
- struct sched_entity *se = __pick_next_entity(cfs_rq);
-
- if (cfs_rq->next && wakeup_preempt_entity(cfs_rq->next, se) < 1)
- return cfs_rq->next;
-
- if (cfs_rq->last && wakeup_preempt_entity(cfs_rq->last, se) < 1)
- return cfs_rq->last;
-
- return se;
-}
-
-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);
-
- 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);
-
-#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 || !sched_feat(WAKEUP_PREEMPT))
- check_preempt_tick(cfs_rq, curr);
-}
-
-/**************************************************
- * 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 wakeup)
-{
- 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, wakeup);
- wakeup = 1;
- }
-
- hrtick_update(rq);
-}
-
-/*
- * 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 sleep)
-{
- struct cfs_rq *cfs_rq;
- struct sched_entity *se = &p->se;
-
- for_each_sched_entity(se) {
- cfs_rq = cfs_rq_of(se);
- dequeue_entity(cfs_rq, se, sleep);
- /* Don't dequeue parent if it has other entities besides us */
- if (cfs_rq->load.weight)
- break;
- sleep = 1;
- }
-
- hrtick_update(rq);
-}
-
-/*
- * sched_yield() support is very simple - we dequeue and enqueue.
- *
- * If compat_yield is turned on then we requeue to the end of the tree.
- */
-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 *rightmost, *se = &curr->se;
-
- /*
- * Are we the only task in the tree?
- */
- if (unlikely(cfs_rq->nr_running == 1))
- return;
-
- clear_buddies(cfs_rq, se);
-
- if (likely(!sysctl_sched_compat_yield) && curr->policy != SCHED_BATCH) {
- update_rq_clock(rq);
- /*
- * Update run-time statistics of the 'current'.
- */
- update_curr(cfs_rq);
-
- return;
- }
- /*
- * Find the rightmost entry in the rbtree:
- */
- rightmost = __pick_last_entity(cfs_rq);
- /*
- * Already in the rightmost position?
- */
- if (unlikely(!rightmost || rightmost->vruntime < se->vruntime))
- return;
-
- /*
- * Minimally necessary key value to be last in the tree:
- * Upon rescheduling, sched_class::put_prev_task() will place
- * 'current' within the tree based on its new key value.
- */
- se->vruntime = rightmost->vruntime + 1;
-}
-
-/*
- * wake_idle() will wake a task on an idle cpu if task->cpu is
- * not idle and an idle cpu is available. The span of cpus to
- * search starts with cpus closest then further out as needed,
- * so we always favor a closer, idle cpu.
- * Domains may include CPUs that are not usable for migration,
- * hence we need to mask them out (cpu_active_mask)
- *
- * Returns the CPU we should wake onto.
- */
-#if defined(ARCH_HAS_SCHED_WAKE_IDLE)
-static int wake_idle(int cpu, struct task_struct *p)
-{
- struct sched_domain *sd;
- int i;
- unsigned int chosen_wakeup_cpu;
- int this_cpu;
-
- /*
- * At POWERSAVINGS_BALANCE_WAKEUP level, if both this_cpu and prev_cpu
- * are idle and this is not a kernel thread and this task's affinity
- * allows it to be moved to preferred cpu, then just move!
- */
-
- this_cpu = smp_processor_id();
- chosen_wakeup_cpu =
- cpu_rq(this_cpu)->rd->sched_mc_preferred_wakeup_cpu;
-
- if (sched_mc_power_savings >= POWERSAVINGS_BALANCE_WAKEUP &&
- idle_cpu(cpu) && idle_cpu(this_cpu) &&
- p->mm && !(p->flags & PF_KTHREAD) &&
- cpu_isset(chosen_wakeup_cpu, p->cpus_allowed))
- return chosen_wakeup_cpu;
-
- /*
- * If it is idle, then it is the best cpu to run this task.
- *
- * This cpu is also the best, if it has more than one task already.
- * Siblings must be also busy(in most cases) as they didn't already
- * pickup the extra load from this cpu and hence we need not check
- * sibling runqueue info. This will avoid the checks and cache miss
- * penalities associated with that.
- */
- if (idle_cpu(cpu) || cpu_rq(cpu)->cfs.nr_running > 1)
- return cpu;
-
- for_each_domain(cpu, sd) {
- if ((sd->flags & SD_WAKE_IDLE)
- || ((sd->flags & SD_WAKE_IDLE_FAR)
- && !task_hot(p, task_rq(p)->clock, sd))) {
- for_each_cpu_and(i, sched_domain_span(sd),
- &p->cpus_allowed) {
- if (cpu_active(i) && idle_cpu(i)) {
- if (i != task_cpu(p)) {
- schedstat_inc(p,
- se.nr_wakeups_idle);
- }
- return i;
- }
- }
- } else {
- break;
- }
- }
- return cpu;
-}
-#else /* !ARCH_HAS_SCHED_WAKE_IDLE*/
-static inline int wake_idle(int cpu, struct task_struct *p)
-{
- return cpu;
-}
-#endif
-
-#ifdef CONFIG_SMP
-
-#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.
- *
- * The problem is that perfectly aligning the shares is rather expensive, hence
- * we try to avoid doing that too often - see update_shares(), which ratelimits
- * this change.
- *
- * We compensate this by not only taking the current delta into account, but
- * also considering the delta between when the shares were last adjusted and
- * now.
- *
- * We still saw a performance dip, some tracing learned us that between
- * cgroup:/ and cgroup:/foo balancing the number of affine wakeups increased
- * significantly. Therefore try to bias the error in direction of failing
- * the affine wakeup.
- *
- */
-static long effective_load(struct task_group *tg, int cpu,
- long wl, long wg)
-{
- struct sched_entity *se = tg->se[cpu];
-
- if (!tg->parent)
- return wl;
-
- /*
- * By not taking the decrease of shares on the other cpu into
- * account our error leans towards reducing the affine wakeups.
- */
- if (!wl && sched_feat(ASYM_EFF_LOAD))
- return wl;
-
- for_each_sched_entity(se) {
- long S, rw, s, a, b;
- long more_w;
-
- /*
- * Instead of using this increment, also add the difference
- * between when the shares were last updated and now.
- */
- more_w = se->my_q->load.weight - se->my_q->rq_weight;
- wl += more_w;
- wg += more_w;
-
- S = se->my_q->tg->shares;
- s = se->my_q->shares;
- rw = se->my_q->rq_weight;
-
- a = S*(rw + wl);
- b = S*rw + s*wg;
-
- wl = s*(a-b);
-
- if (likely(b))
- wl /= b;
-
- /*
- * Assume the group is already running and will
- * thus already be accounted for in the weight.
- *
- * That is, moving shares between CPUs, does not
- * alter the group weight.
- */
- 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 *this_sd, struct rq *this_rq,
- struct task_struct *p, int prev_cpu, int this_cpu, int sync,
- int idx, unsigned long load, unsigned long this_load,
- unsigned int imbalance)
-{
- struct task_struct *curr = this_rq->curr;
- struct task_group *tg;
- unsigned long tl = this_load;
- unsigned long tl_per_task;
- unsigned long weight;
- int balanced;
-
- if (!(this_sd->flags & SD_WAKE_AFFINE) || !sched_feat(AFFINE_WAKEUPS))
- return 0;
-
- if (sync && (curr->se.avg_overlap > sysctl_sched_migration_cost ||
- p->se.avg_overlap > sysctl_sched_migration_cost))
- sync = 0;
-
- /*
- * 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;
-
- tl += effective_load(tg, this_cpu, -weight, -weight);
- load += effective_load(tg, prev_cpu, 0, -weight);
- }
-
- tg = task_group(p);
- weight = p->se.load.weight;
-
- balanced = 100*(tl + effective_load(tg, this_cpu, weight, weight)) <=
- imbalance*(load + effective_load(tg, prev_cpu, 0, weight));
-
- /*
- * 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.nr_wakeups_affine_attempts);
- tl_per_task = cpu_avg_load_per_task(this_cpu);
-
- if (balanced || (tl <= load && tl + 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(this_sd, ttwu_move_affine);
- schedstat_inc(p, se.nr_wakeups_affine);
-
- return 1;
- }
- return 0;
-}
-
-static int select_task_rq_fair(struct task_struct *p, int sync)
-{
- struct sched_domain *sd, *this_sd = NULL;
- int prev_cpu, this_cpu, new_cpu;
- unsigned long load, this_load;
- struct rq *this_rq;
- unsigned int imbalance;
- int idx;
-
- prev_cpu = task_cpu(p);
- this_cpu = smp_processor_id();
- this_rq = cpu_rq(this_cpu);
- new_cpu = prev_cpu;
-
- if (prev_cpu == this_cpu)
- goto out;
- /*
- * 'this_sd' is the first domain that both
- * this_cpu and prev_cpu are present in:
- */
- for_each_domain(this_cpu, sd) {
- if (cpumask_test_cpu(prev_cpu, sched_domain_span(sd))) {
- this_sd = sd;
- break;
- }
- }
-
- if (unlikely(!cpumask_test_cpu(this_cpu, &p->cpus_allowed)))
- goto out;
-
- /*
- * Check for affine wakeup and passive balancing possibilities.
- */
- if (!this_sd)
- goto out;
-
- idx = this_sd->wake_idx;
-
- imbalance = 100 + (this_sd->imbalance_pct - 100) / 2;
-
- load = source_load(prev_cpu, idx);
- this_load = target_load(this_cpu, idx);
-
- if (wake_affine(this_sd, this_rq, p, prev_cpu, this_cpu, sync, idx,
- load, this_load, imbalance))
- return this_cpu;
-
- /*
- * Start passive balancing when half the imbalance_pct
- * limit is reached.
- */
- if (this_sd->flags & SD_WAKE_BALANCE) {
- if (imbalance*this_load <= 100*load) {
- schedstat_inc(this_sd, ttwu_move_balance);
- schedstat_inc(p, se.nr_wakeups_passive);
- return this_cpu;
- }
- }
-
-out:
- return wake_idle(new_cpu, p);
-}
-#endif /* CONFIG_SMP */
-
-/*
- * Adaptive granularity
- *
- * se->avg_wakeup gives the average time a task runs until it does a wakeup,
- * with the limit of wakeup_gran -- when it never does a wakeup.
- *
- * So the smaller avg_wakeup is the faster we want this task to preempt,
- * but we don't want to treat the preemptee unfairly and therefore allow it
- * to run for at least the amount of time we'd like to run.
- *
- * NOTE: we use 2*avg_wakeup to increase the probability of actually doing one
- *
- * NOTE: we use *nr_running to scale with load, this nicely matches the
- * degrading latency on load.
- */
-static unsigned long
-adaptive_gran(struct sched_entity *curr, struct sched_entity *se)
-{
- u64 this_run = curr->sum_exec_runtime - curr->prev_sum_exec_runtime;
- u64 expected_wakeup = 2*se->avg_wakeup * cfs_rq_of(se)->nr_running;
- u64 gran = 0;
-
- if (this_run < expected_wakeup)
- gran = expected_wakeup - this_run;
-
- return min_t(s64, gran, sysctl_sched_wakeup_granularity);
-}
-
-static unsigned long
-wakeup_gran(struct sched_entity *curr, struct sched_entity *se)
-{
- unsigned long gran = sysctl_sched_wakeup_granularity;
-
- if (cfs_rq_of(curr)->curr && sched_feat(ADAPTIVE_GRAN))
- gran = adaptive_gran(curr, se);
-
- /*
- * Since its curr running now, convert the gran from real-time
- * to virtual-time in his units.
- */
- if (sched_feat(ASYM_GRAN)) {
- /*
- * 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.
- */
- if (unlikely(se->load.weight != NICE_0_LOAD))
- gran = calc_delta_fair(gran, se);
- } else {
- if (unlikely(curr->load.weight != NICE_0_LOAD))
- gran = calc_delta_fair(gran, curr);
- }
-
- return gran;
-}
-
-/*
- * 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 (likely(task_of(se)->policy != SCHED_IDLE)) {
- for_each_sched_entity(se)
- cfs_rq_of(se)->last = se;
- }
-}
-
-static void set_next_buddy(struct sched_entity *se)
-{
- if (likely(task_of(se)->policy != SCHED_IDLE)) {
- for_each_sched_entity(se)
- cfs_rq_of(se)->next = 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 sync)
-{
- struct task_struct *curr = rq->curr;
- struct sched_entity *se = &curr->se, *pse = &p->se;
- struct cfs_rq *cfs_rq = task_cfs_rq(curr);
-
- update_curr(cfs_rq);
-
- if (unlikely(rt_prio(p->prio))) {
- resched_task(curr);
- return;
- }
-
- if (unlikely(p->sched_class != &fair_sched_class))
- return;
-
- if (unlikely(se == pse))
- return;
-
- /*
- * 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 the idle thread.
- */
- if (sched_feat(LAST_BUDDY) && likely(se->on_rq && curr != rq->idle))
- set_last_buddy(se);
- set_next_buddy(pse);
-
- /*
- * We can come here with TIF_NEED_RESCHED already set from new task
- * wake up path.
- */
- if (test_tsk_need_resched(curr))
- return;
-
- /*
- * Batch and idle tasks do not preempt (their preemption is driven by
- * the tick):
- */
- if (unlikely(p->policy != SCHED_NORMAL))
- return;
-
- /* Idle tasks are by definition preempted by everybody. */
- if (unlikely(curr->policy == SCHED_IDLE)) {
- resched_task(curr);
- return;
- }
-
- if (!sched_feat(WAKEUP_PREEMPT))
- return;
-
- if (sched_feat(WAKEUP_OVERLAP) && (sync ||
- (se->avg_overlap < sysctl_sched_migration_cost &&
- pse->avg_overlap < sysctl_sched_migration_cost))) {
- resched_task(curr);
- return;
- }
-
- find_matching_se(&se, &pse);
-
- BUG_ON(!pse);
-
- if (wakeup_preempt_entity(se, pse) == 1)
- resched_task(curr);
-}
-
-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 (unlikely(!cfs_rq->nr_running))
- return NULL;
-
- do {
- se = pick_next_entity(cfs_rq);
- /*
- * If se was a buddy, clear it so that it will have to earn
- * the favour again.
- */
- __clear_buddies(cfs_rq, se);
- 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);
- }
-}
-
-#ifdef CONFIG_SMP
-/**************************************************
- * Fair scheduling class load-balancing methods:
- */
-
-/*
- * Load-balancing iterator. Note: while the runqueue stays locked
- * during the whole iteration, the current task might be
- * dequeued so the iterator has to be dequeue-safe. Here we
- * achieve that by always pre-iterating before returning
- * the current task:
- */
-static struct task_struct *
-__load_balance_iterator(struct cfs_rq *cfs_rq, struct list_head *next)
-{
- struct task_struct *p = NULL;
- struct sched_entity *se;
-
- if (next == &cfs_rq->tasks)
- return NULL;
-
- se = list_entry(next, struct sched_entity, group_node);
- p = task_of(se);
- cfs_rq->balance_iterator = next->next;
-
- return p;
-}
-
-static struct task_struct *load_balance_start_fair(void *arg)
-{
- struct cfs_rq *cfs_rq = arg;
-
- return __load_balance_iterator(cfs_rq, cfs_rq->tasks.next);
-}
-
-static struct task_struct *load_balance_next_fair(void *arg)
-{
- struct cfs_rq *cfs_rq = arg;
-
- return __load_balance_iterator(cfs_rq, cfs_rq->balance_iterator);
-}
-
-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, int *this_best_prio,
- struct cfs_rq *cfs_rq)
-{
- struct rq_iterator cfs_rq_iterator;
-
- cfs_rq_iterator.start = load_balance_start_fair;
- cfs_rq_iterator.next = load_balance_next_fair;
- cfs_rq_iterator.arg = cfs_rq;
-
- return balance_tasks(this_rq, this_cpu, busiest,
- max_load_move, sd, idle, all_pinned,
- this_best_prio, &cfs_rq_iterator);
-}
-
-#ifdef CONFIG_FAIR_GROUP_SCHED
-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, int *this_best_prio)
-{
- long rem_load_move = max_load_move;
- int busiest_cpu = cpu_of(busiest);
- struct task_group *tg;
-
- rcu_read_lock();
- update_h_load(busiest_cpu);
-
- list_for_each_entry_rcu(tg, &task_groups, list) {
- struct cfs_rq *busiest_cfs_rq = tg->cfs_rq[busiest_cpu];
- 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
- */
- if (!busiest_cfs_rq->task_weight)
- continue;
-
- rem_load = (u64)rem_load_move * busiest_weight;
- rem_load = div_u64(rem_load, busiest_h_load + 1);
-
- moved_load = __load_balance_fair(this_rq, this_cpu, busiest,
- rem_load, sd, idle, all_pinned, this_best_prio,
- tg->cfs_rq[busiest_cpu]);
-
- 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 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, int *this_best_prio)
-{
- return __load_balance_fair(this_rq, this_cpu, busiest,
- max_load_move, sd, idle, all_pinned,
- this_best_prio, &busiest->cfs);
-}
-#endif
-
-static int
-move_one_task_fair(struct rq *this_rq, int this_cpu, struct rq *busiest,
- struct sched_domain *sd, enum cpu_idle_type idle)
-{
- struct cfs_rq *busy_cfs_rq;
- struct rq_iterator cfs_rq_iterator;
-
- cfs_rq_iterator.start = load_balance_start_fair;
- cfs_rq_iterator.next = load_balance_next_fair;
-
- for_each_leaf_cfs_rq(busiest, busy_cfs_rq) {
- /*
- * pass busy_cfs_rq argument into
- * load_balance_[start|next]_fair iterators
- */
- cfs_rq_iterator.arg = busy_cfs_rq;
- if (iter_move_one_task(this_rq, this_cpu, busiest, sd, idle,
- &cfs_rq_iterator))
- return 1;
- }
-
- return 0;
-}
-#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);
- }
-}
-
-/*
- * Share the fairness runtime between parent and child, thus the
- * total amount of pressure for CPU stays equal - new tasks
- * get a chance to run but frequent forkers are not allowed to
- * monopolize the CPU. Note: the parent runqueue is locked,
- * the child is not running yet.
- */
-static void task_new_fair(struct rq *rq, struct task_struct *p)
-{
- struct cfs_rq *cfs_rq = task_cfs_rq(p);
- struct sched_entity *se = &p->se, *curr = cfs_rq->curr;
- int this_cpu = smp_processor_id();
-
- sched_info_queued(p);
-
- update_curr(cfs_rq);
- place_entity(cfs_rq, se, 1);
-
- /* 'curr' will be NULL if the child belongs to a different group */
- if (sysctl_sched_child_runs_first && this_cpu == task_cpu(p) &&
- curr && curr->vruntime < se->vruntime) {
- /*
- * 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);
- }
-
- enqueue_task_fair(rq, p, 0);
-}
-
-/*
- * 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, int running)
-{
- /*
- * 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 (running) {
- if (p->prio > oldprio)
- resched_task(rq->curr);
- } else
- check_preempt_curr(rq, p, 0);
-}
-
-/*
- * We switched to the sched_fair class.
- */
-static void switched_to_fair(struct rq *rq, struct task_struct *p,
- int running)
-{
- /*
- * 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 (running)
- 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)
- set_next_entity(cfs_rq_of(se), se);
-}
-
-#ifdef CONFIG_FAIR_GROUP_SCHED
-static void moved_group_fair(struct task_struct *p)
-{
- struct cfs_rq *cfs_rq = task_cfs_rq(p);
-
- update_curr(cfs_rq);
- place_entity(cfs_rq, &p->se, 1);
-}
-#endif
-
-/*
- * All the scheduling class methods:
- */
-static 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,
-
- .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,
-
- .load_balance = load_balance_fair,
- .move_one_task = move_one_task_fair,
-#endif
-
- .set_curr_task = set_curr_task_fair,
- .task_tick = task_tick_fair,
- .task_new = task_new_fair,
-
- .prio_changed = prio_changed_fair,
- .switched_to = switched_to_fair,
-
-#ifdef CONFIG_FAIR_GROUP_SCHED
- .moved_group = moved_group_fair,
-#endif
-};
-
-#ifdef CONFIG_SCHED_DEBUG
-static 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
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