diff options
Diffstat (limited to 'kernel/sched_fair.c')
| -rw-r--r-- | kernel/sched_fair.c | 2143 |
1 files changed, 0 insertions, 2143 deletions
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c deleted file mode 100644 index 42ac3c9f66f..00000000000 --- a/kernel/sched_fair.c +++ /dev/null @@ -1,2143 +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> - -/* - * Targeted preemption latency for CPU-bound tasks: - * (default: 5ms * (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 = 5000000ULL; -unsigned int normalized_sysctl_sched_latency = 5000000ULL; - -/* - * 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: 1 msec * (1 + ilog(ncpus)), units: nanoseconds) - */ -unsigned int sysctl_sched_min_granularity = 1000000ULL; -unsigned int normalized_sysctl_sched_min_granularity = 1000000ULL; - -/* - * is kept at sysctl_sched_latency / sysctl_sched_min_granularity - */ -static unsigned int sched_nr_latency = 5; - -/* - * 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; - -/* - * 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: 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; - -static 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; -} - -/* 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 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 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 int entity_before(struct sched_entity *a, - struct sched_entity *b) -{ - return (s64)(a->vruntime - b->vruntime) < 0; -} - -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_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); - WRT_SYSCTL(sched_shares_ratelimit); -#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); -} - -/* - * 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); - - trace_sched_stat_runtime(curtask, delta_exec, curr->vruntime); - 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); -#ifdef CONFIG_SCHEDSTATS - if (entity_is_task(se)) { - trace_sched_stat_wait(task_of(se), - rq_of(cfs_rq)->clock - se->wait_start); - } -#endif - 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 - struct task_struct *tsk = NULL; - - if (entity_is_task(se)) - tsk = task_of(se); - - if (se->sleep_start) { - u64 delta = rq_of(cfs_rq)->clock - se->sleep_start; - - 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; - - if (tsk) { - account_scheduler_latency(tsk, delta >> 10, 1); - trace_sched_stat_sleep(tsk, delta); - } - } - if (se->block_start) { - u64 delta = rq_of(cfs_rq)->clock - se->block_start; - - 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; - - if (tsk) { - if (tsk->in_iowait) { - se->iowait_sum += delta; - se->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 && sched_feat(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) && (!entity_is_task(se) || - task_of(se)->policy != SCHED_IDLE)) - thresh = calc_delta_fair(thresh, se); - - /* - * 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; -} - -#define ENQUEUE_WAKEUP 1 -#define ENQUEUE_MIGRATE 2 - -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_MIGRATE)) - se->vruntime += cfs_rq->min_vruntime; - - /* - * Update run-time statistics of the 'current'. - */ - update_curr(cfs_rq); - account_entity_enqueue(cfs_rq, se); - - 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); -} - -static void __clear_buddies(struct cfs_rq *cfs_rq, struct sched_entity *se) -{ - if (!se || cfs_rq->last == se) - cfs_rq->last = NULL; - - if (!se || 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); - - /* - * 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 (!sleep) - se->vruntime -= cfs_rq->min_vruntime; -} - -/* - * 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); - 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 (!sched_feat(WAKEUP_PREEMPT)) - return; - - if (delta_exec < sysctl_sched_min_granularity) - return; - - if (cfs_rq->nr_running > 1) { - struct sched_entity *se = __pick_next_entity(cfs_rq); - s64 delta = curr->vruntime - se->vruntime; - - 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->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); - struct sched_entity *left = se; - - if (cfs_rq->next && wakeup_preempt_entity(cfs_rq->next, left) < 1) - se = cfs_rq->next; - - /* - * 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; - - clear_buddies(cfs_rq, se); - - 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; - int flags = 0; - - if (wakeup) - flags |= ENQUEUE_WAKEUP; - if (p->state == TASK_WAKING) - flags |= ENQUEUE_MIGRATE; - - for_each_sched_entity(se) { - if (se->on_rq) - break; - cfs_rq = cfs_rq_of(se); - enqueue_entity(cfs_rq, se, flags); - flags = ENQUEUE_WAKEUP; - } - - 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 || entity_before(rightmost, se))) - 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; -} - -#ifdef CONFIG_SMP - -static void task_waking_fair(struct rq *rq, struct task_struct *p) -{ - struct sched_entity *se = &p->se; - struct cfs_rq *cfs_rq = cfs_rq_of(se); - - se->vruntime -= cfs_rq->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. - * - * 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 *sd, struct task_struct *p, int sync) -{ - struct task_struct *curr = current; - unsigned long this_load, load; - int idx, this_cpu, prev_cpu; - unsigned long tl_per_task; - unsigned int imbalance; - 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) { - if (sched_feat(SYNC_LESS) && - (curr->se.avg_overlap > sysctl_sched_migration_cost || - p->se.avg_overlap > sysctl_sched_migration_cost)) - sync = 0; - } else { - if (sched_feat(SYNC_MORE) && - (curr->se.avg_overlap < sysctl_sched_migration_cost && - p->se.avg_overlap < sysctl_sched_migration_cost)) - sync = 1; - } - - /* - * 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; - - imbalance = 100 + (sd->imbalance_pct - 100) / 2; - - /* - * 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. - */ - balanced = !this_load || - 100*(this_load + 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 || - (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.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, *this = 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), - &p->cpus_allowed)) - 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_LOAD_SCALE) / group->cpu_power; - - if (local_group) { - this_load = avg_load; - this = group; - } 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), &p->cpus_allowed) { - 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, struct sched_domain *sd, int target) -{ - int cpu = smp_processor_id(); - int prev_cpu = task_cpu(p); - int i; - - /* - * If this domain spans both cpu and prev_cpu (see the SD_WAKE_AFFINE - * test in select_task_rq_fair) and the prev_cpu is idle then that's - * always a better target than the current cpu. - */ - if (target == cpu && !cpu_rq(prev_cpu)->cfs.nr_running) - return prev_cpu; - - /* - * Otherwise, iterate the domain and find an elegible idle cpu. - */ - for_each_cpu_and(i, sched_domain_span(sd), &p->cpus_allowed) { - if (!cpu_rq(i)->cfs.nr_running) { - target = i; - break; - } - } - - 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 (sched_feat(AFFINE_WAKEUPS) && - cpumask_test_cpu(cpu, &p->cpus_allowed)) - want_affine = 1; - new_cpu = prev_cpu; - } - - 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_LOAD_SCALE); - - if (tmp->flags & SD_POWERSAVINGS_BALANCE) - nr_running /= 2; - - if (nr_running < capacity) - want_sd = 0; - } - - /* - * While iterating the domains looking for a spanning - * WAKE_AFFINE domain, adjust the affine target to any idle cpu - * in cache sharing domains along the way. - */ - if (want_affine) { - int target = -1; - - /* - * If both cpu and prev_cpu are part of this domain, - * cpu is a valid SD_WAKE_AFFINE target. - */ - if (cpumask_test_cpu(prev_cpu, sched_domain_span(tmp))) - target = cpu; - - /* - * If there's an idle sibling in this domain, make that - * the wake_affine target instead of the current cpu. - */ - if (tmp->flags & SD_PREFER_SIBLING) - target = select_idle_sibling(p, tmp, target); - - if (target >= 0) { - if (tmp->flags & SD_WAKE_AFFINE) { - affine_sd = tmp; - want_affine = 0; - } - cpu = target; - } - } - - if (!want_sd && !want_affine) - break; - - if (!(tmp->flags & sd_flag)) - continue; - - if (want_sd) - sd = tmp; - } - - if (sched_feat(LB_SHARES_UPDATE)) { - /* - * Pick the largest domain to update shares over - */ - tmp = sd; - if (affine_sd && (!tmp || - cpumask_weight(sched_domain_span(affine_sd)) > - cpumask_weight(sched_domain_span(sd)))) - tmp = affine_sd; - - if (tmp) - update_shares(tmp); - } - - if (affine_sd && wake_affine(affine_sd, p, sync)) - return cpu; - - 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 = cpumask_weight(sched_domain_span(sd)); - sd = NULL; - for_each_domain(cpu, tmp) { - if (weight <= cpumask_weight(sched_domain_span(tmp))) - break; - if (tmp->flags & sd_flag) - sd = tmp; - } - /* while loop will break here if sd == NULL */ - } - - return new_cpu; -} -#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 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 sync = wake_flags & WF_SYNC; - int scale = cfs_rq->nr_running >= sched_nr_latency; - - if (unlikely(rt_prio(p->prio))) - goto preempt; - - if (unlikely(p->sched_class != &fair_sched_class)) - return; - - if (unlikely(se == pse)) - return; - - if (sched_feat(NEXT_BUDDY) && scale && !(wake_flags & WF_FORK)) - 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)) - goto preempt; - - if (sched_feat(WAKEUP_SYNC) && sync) - goto preempt; - - if (sched_feat(WAKEUP_OVERLAP) && - se->avg_overlap < sysctl_sched_migration_cost && - pse->avg_overlap < sysctl_sched_migration_cost) - goto preempt; - - if (!sched_feat(WAKEUP_PREEMPT)) - return; - - update_curr(cfs_rq); - find_matching_se(&se, &pse); - BUG_ON(!pse); - if (wakeup_preempt_entity(se, pse) == 1) - 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); - } -} - -#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; -} - -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); - - if (unlikely(task_cpu(p) != this_cpu)) - __set_task_cpu(p, this_cpu); - - 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, 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, int on_rq) -{ - struct cfs_rq *cfs_rq = task_cfs_rq(p); - - update_curr(cfs_rq); - if (!on_rq) - place_entity(cfs_rq, &p->se, 1); -} -#endif - -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: - */ -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, - .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_to = switched_to_fair, - - .get_rr_interval = get_rr_interval_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 |