2 * Real-Time Scheduling Class (mapped to the SCHED_FIFO and SCHED_RR
8 #include <linux/slab.h>
10 int sched_rr_timeslice = RR_TIMESLICE;
12 static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun);
14 struct rt_bandwidth def_rt_bandwidth;
16 static enum hrtimer_restart sched_rt_period_timer(struct hrtimer *timer)
18 struct rt_bandwidth *rt_b =
19 container_of(timer, struct rt_bandwidth, rt_period_timer);
25 now = hrtimer_cb_get_time(timer);
26 overrun = hrtimer_forward(timer, now, rt_b->rt_period);
31 idle = do_sched_rt_period_timer(rt_b, overrun);
34 return idle ? HRTIMER_NORESTART : HRTIMER_RESTART;
37 void init_rt_bandwidth(struct rt_bandwidth *rt_b, u64 period, u64 runtime)
39 rt_b->rt_period = ns_to_ktime(period);
40 rt_b->rt_runtime = runtime;
42 raw_spin_lock_init(&rt_b->rt_runtime_lock);
44 hrtimer_init(&rt_b->rt_period_timer,
45 CLOCK_MONOTONIC, HRTIMER_MODE_REL);
46 rt_b->rt_period_timer.function = sched_rt_period_timer;
49 static void start_rt_bandwidth(struct rt_bandwidth *rt_b)
51 if (!rt_bandwidth_enabled() || rt_b->rt_runtime == RUNTIME_INF)
54 if (hrtimer_active(&rt_b->rt_period_timer))
57 raw_spin_lock(&rt_b->rt_runtime_lock);
58 start_bandwidth_timer(&rt_b->rt_period_timer, rt_b->rt_period);
59 raw_spin_unlock(&rt_b->rt_runtime_lock);
62 void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq)
64 struct rt_prio_array *array;
67 array = &rt_rq->active;
68 for (i = 0; i < MAX_RT_PRIO; i++) {
69 INIT_LIST_HEAD(array->queue + i);
70 __clear_bit(i, array->bitmap);
72 /* delimiter for bitsearch: */
73 __set_bit(MAX_RT_PRIO, array->bitmap);
75 #if defined CONFIG_SMP
76 rt_rq->highest_prio.curr = MAX_RT_PRIO;
77 rt_rq->highest_prio.next = MAX_RT_PRIO;
78 rt_rq->rt_nr_migratory = 0;
79 rt_rq->overloaded = 0;
80 plist_head_init(&rt_rq->pushable_tasks);
84 rt_rq->rt_throttled = 0;
85 rt_rq->rt_runtime = 0;
86 raw_spin_lock_init(&rt_rq->rt_runtime_lock);
89 #ifdef CONFIG_RT_GROUP_SCHED
90 static void destroy_rt_bandwidth(struct rt_bandwidth *rt_b)
92 hrtimer_cancel(&rt_b->rt_period_timer);
95 #define rt_entity_is_task(rt_se) (!(rt_se)->my_q)
97 static inline struct task_struct *rt_task_of(struct sched_rt_entity *rt_se)
99 #ifdef CONFIG_SCHED_DEBUG
100 WARN_ON_ONCE(!rt_entity_is_task(rt_se));
102 return container_of(rt_se, struct task_struct, rt);
105 static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq)
110 static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se)
115 void free_rt_sched_group(struct task_group *tg)
120 destroy_rt_bandwidth(&tg->rt_bandwidth);
122 for_each_possible_cpu(i) {
133 void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq,
134 struct sched_rt_entity *rt_se, int cpu,
135 struct sched_rt_entity *parent)
137 struct rq *rq = cpu_rq(cpu);
139 rt_rq->highest_prio.curr = MAX_RT_PRIO;
140 rt_rq->rt_nr_boosted = 0;
144 tg->rt_rq[cpu] = rt_rq;
145 tg->rt_se[cpu] = rt_se;
151 rt_se->rt_rq = &rq->rt;
153 rt_se->rt_rq = parent->my_q;
156 rt_se->parent = parent;
157 INIT_LIST_HEAD(&rt_se->run_list);
160 int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
163 struct sched_rt_entity *rt_se;
166 tg->rt_rq = kzalloc(sizeof(rt_rq) * nr_cpu_ids, GFP_KERNEL);
169 tg->rt_se = kzalloc(sizeof(rt_se) * nr_cpu_ids, GFP_KERNEL);
173 init_rt_bandwidth(&tg->rt_bandwidth,
174 ktime_to_ns(def_rt_bandwidth.rt_period), 0);
176 for_each_possible_cpu(i) {
177 rt_rq = kzalloc_node(sizeof(struct rt_rq),
178 GFP_KERNEL, cpu_to_node(i));
182 rt_se = kzalloc_node(sizeof(struct sched_rt_entity),
183 GFP_KERNEL, cpu_to_node(i));
187 init_rt_rq(rt_rq, cpu_rq(i));
188 rt_rq->rt_runtime = tg->rt_bandwidth.rt_runtime;
189 init_tg_rt_entry(tg, rt_rq, rt_se, i, parent->rt_se[i]);
200 #else /* CONFIG_RT_GROUP_SCHED */
202 #define rt_entity_is_task(rt_se) (1)
204 static inline struct task_struct *rt_task_of(struct sched_rt_entity *rt_se)
206 return container_of(rt_se, struct task_struct, rt);
209 static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq)
211 return container_of(rt_rq, struct rq, rt);
214 static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se)
216 struct task_struct *p = rt_task_of(rt_se);
217 struct rq *rq = task_rq(p);
222 void free_rt_sched_group(struct task_group *tg) { }
224 int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
228 #endif /* CONFIG_RT_GROUP_SCHED */
232 static inline int rt_overloaded(struct rq *rq)
234 return atomic_read(&rq->rd->rto_count);
237 static inline void rt_set_overload(struct rq *rq)
242 cpumask_set_cpu(rq->cpu, rq->rd->rto_mask);
244 * Make sure the mask is visible before we set
245 * the overload count. That is checked to determine
246 * if we should look at the mask. It would be a shame
247 * if we looked at the mask, but the mask was not
250 * Matched by the barrier in pull_rt_task().
253 atomic_inc(&rq->rd->rto_count);
256 static inline void rt_clear_overload(struct rq *rq)
261 /* the order here really doesn't matter */
262 atomic_dec(&rq->rd->rto_count);
263 cpumask_clear_cpu(rq->cpu, rq->rd->rto_mask);
266 static void update_rt_migration(struct rt_rq *rt_rq)
268 if (rt_rq->rt_nr_migratory && rt_rq->rt_nr_total > 1) {
269 if (!rt_rq->overloaded) {
270 rt_set_overload(rq_of_rt_rq(rt_rq));
271 rt_rq->overloaded = 1;
273 } else if (rt_rq->overloaded) {
274 rt_clear_overload(rq_of_rt_rq(rt_rq));
275 rt_rq->overloaded = 0;
279 static void inc_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
281 struct task_struct *p;
283 if (!rt_entity_is_task(rt_se))
286 p = rt_task_of(rt_se);
287 rt_rq = &rq_of_rt_rq(rt_rq)->rt;
289 rt_rq->rt_nr_total++;
290 if (p->nr_cpus_allowed > 1)
291 rt_rq->rt_nr_migratory++;
293 update_rt_migration(rt_rq);
296 static void dec_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
298 struct task_struct *p;
300 if (!rt_entity_is_task(rt_se))
303 p = rt_task_of(rt_se);
304 rt_rq = &rq_of_rt_rq(rt_rq)->rt;
306 rt_rq->rt_nr_total--;
307 if (p->nr_cpus_allowed > 1)
308 rt_rq->rt_nr_migratory--;
310 update_rt_migration(rt_rq);
313 static inline int has_pushable_tasks(struct rq *rq)
315 return !plist_head_empty(&rq->rt.pushable_tasks);
318 static void enqueue_pushable_task(struct rq *rq, struct task_struct *p)
320 plist_del(&p->pushable_tasks, &rq->rt.pushable_tasks);
321 plist_node_init(&p->pushable_tasks, p->prio);
322 plist_add(&p->pushable_tasks, &rq->rt.pushable_tasks);
324 /* Update the highest prio pushable task */
325 if (p->prio < rq->rt.highest_prio.next)
326 rq->rt.highest_prio.next = p->prio;
329 static void dequeue_pushable_task(struct rq *rq, struct task_struct *p)
331 plist_del(&p->pushable_tasks, &rq->rt.pushable_tasks);
333 /* Update the new highest prio pushable task */
334 if (has_pushable_tasks(rq)) {
335 p = plist_first_entry(&rq->rt.pushable_tasks,
336 struct task_struct, pushable_tasks);
337 rq->rt.highest_prio.next = p->prio;
339 rq->rt.highest_prio.next = MAX_RT_PRIO;
344 static inline void enqueue_pushable_task(struct rq *rq, struct task_struct *p)
348 static inline void dequeue_pushable_task(struct rq *rq, struct task_struct *p)
353 void inc_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
358 void dec_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
362 #endif /* CONFIG_SMP */
364 static inline int on_rt_rq(struct sched_rt_entity *rt_se)
366 return !list_empty(&rt_se->run_list);
369 #ifdef CONFIG_RT_GROUP_SCHED
371 static inline u64 sched_rt_runtime(struct rt_rq *rt_rq)
376 return rt_rq->rt_runtime;
379 static inline u64 sched_rt_period(struct rt_rq *rt_rq)
381 return ktime_to_ns(rt_rq->tg->rt_bandwidth.rt_period);
384 typedef struct task_group *rt_rq_iter_t;
386 static inline struct task_group *next_task_group(struct task_group *tg)
389 tg = list_entry_rcu(tg->list.next,
390 typeof(struct task_group), list);
391 } while (&tg->list != &task_groups && task_group_is_autogroup(tg));
393 if (&tg->list == &task_groups)
399 #define for_each_rt_rq(rt_rq, iter, rq) \
400 for (iter = container_of(&task_groups, typeof(*iter), list); \
401 (iter = next_task_group(iter)) && \
402 (rt_rq = iter->rt_rq[cpu_of(rq)]);)
404 #define for_each_sched_rt_entity(rt_se) \
405 for (; rt_se; rt_se = rt_se->parent)
407 static inline struct rt_rq *group_rt_rq(struct sched_rt_entity *rt_se)
412 static void enqueue_rt_entity(struct sched_rt_entity *rt_se, bool head);
413 static void dequeue_rt_entity(struct sched_rt_entity *rt_se);
415 static void sched_rt_rq_enqueue(struct rt_rq *rt_rq)
417 struct task_struct *curr = rq_of_rt_rq(rt_rq)->curr;
418 struct sched_rt_entity *rt_se;
420 int cpu = cpu_of(rq_of_rt_rq(rt_rq));
422 rt_se = rt_rq->tg->rt_se[cpu];
424 if (rt_rq->rt_nr_running) {
425 if (rt_se && !on_rt_rq(rt_se))
426 enqueue_rt_entity(rt_se, false);
427 if (rt_rq->highest_prio.curr < curr->prio)
432 static void sched_rt_rq_dequeue(struct rt_rq *rt_rq)
434 struct sched_rt_entity *rt_se;
435 int cpu = cpu_of(rq_of_rt_rq(rt_rq));
437 rt_se = rt_rq->tg->rt_se[cpu];
439 if (rt_se && on_rt_rq(rt_se))
440 dequeue_rt_entity(rt_se);
443 static inline int rt_rq_throttled(struct rt_rq *rt_rq)
445 return rt_rq->rt_throttled && !rt_rq->rt_nr_boosted;
448 static int rt_se_boosted(struct sched_rt_entity *rt_se)
450 struct rt_rq *rt_rq = group_rt_rq(rt_se);
451 struct task_struct *p;
454 return !!rt_rq->rt_nr_boosted;
456 p = rt_task_of(rt_se);
457 return p->prio != p->normal_prio;
461 static inline const struct cpumask *sched_rt_period_mask(void)
463 return this_rq()->rd->span;
466 static inline const struct cpumask *sched_rt_period_mask(void)
468 return cpu_online_mask;
473 struct rt_rq *sched_rt_period_rt_rq(struct rt_bandwidth *rt_b, int cpu)
475 return container_of(rt_b, struct task_group, rt_bandwidth)->rt_rq[cpu];
478 static inline struct rt_bandwidth *sched_rt_bandwidth(struct rt_rq *rt_rq)
480 return &rt_rq->tg->rt_bandwidth;
483 #else /* !CONFIG_RT_GROUP_SCHED */
485 static inline u64 sched_rt_runtime(struct rt_rq *rt_rq)
487 return rt_rq->rt_runtime;
490 static inline u64 sched_rt_period(struct rt_rq *rt_rq)
492 return ktime_to_ns(def_rt_bandwidth.rt_period);
495 typedef struct rt_rq *rt_rq_iter_t;
497 #define for_each_rt_rq(rt_rq, iter, rq) \
498 for ((void) iter, rt_rq = &rq->rt; rt_rq; rt_rq = NULL)
500 #define for_each_sched_rt_entity(rt_se) \
501 for (; rt_se; rt_se = NULL)
503 static inline struct rt_rq *group_rt_rq(struct sched_rt_entity *rt_se)
508 static inline void sched_rt_rq_enqueue(struct rt_rq *rt_rq)
510 if (rt_rq->rt_nr_running)
511 resched_task(rq_of_rt_rq(rt_rq)->curr);
514 static inline void sched_rt_rq_dequeue(struct rt_rq *rt_rq)
518 static inline int rt_rq_throttled(struct rt_rq *rt_rq)
520 return rt_rq->rt_throttled;
523 static inline const struct cpumask *sched_rt_period_mask(void)
525 return cpu_online_mask;
529 struct rt_rq *sched_rt_period_rt_rq(struct rt_bandwidth *rt_b, int cpu)
531 return &cpu_rq(cpu)->rt;
534 static inline struct rt_bandwidth *sched_rt_bandwidth(struct rt_rq *rt_rq)
536 return &def_rt_bandwidth;
539 #endif /* CONFIG_RT_GROUP_SCHED */
541 bool sched_rt_bandwidth_account(struct rt_rq *rt_rq)
543 struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
545 return (hrtimer_active(&rt_b->rt_period_timer) ||
546 rt_rq->rt_time < rt_b->rt_runtime);
551 * We ran out of runtime, see if we can borrow some from our neighbours.
553 static int do_balance_runtime(struct rt_rq *rt_rq)
555 struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
556 struct root_domain *rd = rq_of_rt_rq(rt_rq)->rd;
557 int i, weight, more = 0;
560 weight = cpumask_weight(rd->span);
562 raw_spin_lock(&rt_b->rt_runtime_lock);
563 rt_period = ktime_to_ns(rt_b->rt_period);
564 for_each_cpu(i, rd->span) {
565 struct rt_rq *iter = sched_rt_period_rt_rq(rt_b, i);
571 raw_spin_lock(&iter->rt_runtime_lock);
573 * Either all rqs have inf runtime and there's nothing to steal
574 * or __disable_runtime() below sets a specific rq to inf to
575 * indicate its been disabled and disalow stealing.
577 if (iter->rt_runtime == RUNTIME_INF)
581 * From runqueues with spare time, take 1/n part of their
582 * spare time, but no more than our period.
584 diff = iter->rt_runtime - iter->rt_time;
586 diff = div_u64((u64)diff, weight);
587 if (rt_rq->rt_runtime + diff > rt_period)
588 diff = rt_period - rt_rq->rt_runtime;
589 iter->rt_runtime -= diff;
590 rt_rq->rt_runtime += diff;
592 if (rt_rq->rt_runtime == rt_period) {
593 raw_spin_unlock(&iter->rt_runtime_lock);
598 raw_spin_unlock(&iter->rt_runtime_lock);
600 raw_spin_unlock(&rt_b->rt_runtime_lock);
606 * Ensure this RQ takes back all the runtime it lend to its neighbours.
608 static void __disable_runtime(struct rq *rq)
610 struct root_domain *rd = rq->rd;
614 if (unlikely(!scheduler_running))
617 for_each_rt_rq(rt_rq, iter, rq) {
618 struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
622 raw_spin_lock(&rt_b->rt_runtime_lock);
623 raw_spin_lock(&rt_rq->rt_runtime_lock);
625 * Either we're all inf and nobody needs to borrow, or we're
626 * already disabled and thus have nothing to do, or we have
627 * exactly the right amount of runtime to take out.
629 if (rt_rq->rt_runtime == RUNTIME_INF ||
630 rt_rq->rt_runtime == rt_b->rt_runtime)
632 raw_spin_unlock(&rt_rq->rt_runtime_lock);
635 * Calculate the difference between what we started out with
636 * and what we current have, that's the amount of runtime
637 * we lend and now have to reclaim.
639 want = rt_b->rt_runtime - rt_rq->rt_runtime;
642 * Greedy reclaim, take back as much as we can.
644 for_each_cpu(i, rd->span) {
645 struct rt_rq *iter = sched_rt_period_rt_rq(rt_b, i);
649 * Can't reclaim from ourselves or disabled runqueues.
651 if (iter == rt_rq || iter->rt_runtime == RUNTIME_INF)
654 raw_spin_lock(&iter->rt_runtime_lock);
656 diff = min_t(s64, iter->rt_runtime, want);
657 iter->rt_runtime -= diff;
660 iter->rt_runtime -= want;
663 raw_spin_unlock(&iter->rt_runtime_lock);
669 raw_spin_lock(&rt_rq->rt_runtime_lock);
671 * We cannot be left wanting - that would mean some runtime
672 * leaked out of the system.
677 * Disable all the borrow logic by pretending we have inf
678 * runtime - in which case borrowing doesn't make sense.
680 rt_rq->rt_runtime = RUNTIME_INF;
681 rt_rq->rt_throttled = 0;
682 raw_spin_unlock(&rt_rq->rt_runtime_lock);
683 raw_spin_unlock(&rt_b->rt_runtime_lock);
687 static void __enable_runtime(struct rq *rq)
692 if (unlikely(!scheduler_running))
696 * Reset each runqueue's bandwidth settings
698 for_each_rt_rq(rt_rq, iter, rq) {
699 struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
701 raw_spin_lock(&rt_b->rt_runtime_lock);
702 raw_spin_lock(&rt_rq->rt_runtime_lock);
703 rt_rq->rt_runtime = rt_b->rt_runtime;
705 rt_rq->rt_throttled = 0;
706 raw_spin_unlock(&rt_rq->rt_runtime_lock);
707 raw_spin_unlock(&rt_b->rt_runtime_lock);
711 static int balance_runtime(struct rt_rq *rt_rq)
715 if (!sched_feat(RT_RUNTIME_SHARE))
718 if (rt_rq->rt_time > rt_rq->rt_runtime) {
719 raw_spin_unlock(&rt_rq->rt_runtime_lock);
720 more = do_balance_runtime(rt_rq);
721 raw_spin_lock(&rt_rq->rt_runtime_lock);
726 #else /* !CONFIG_SMP */
727 static inline int balance_runtime(struct rt_rq *rt_rq)
731 #endif /* CONFIG_SMP */
733 static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun)
735 int i, idle = 1, throttled = 0;
736 const struct cpumask *span;
738 span = sched_rt_period_mask();
739 #ifdef CONFIG_RT_GROUP_SCHED
741 * FIXME: isolated CPUs should really leave the root task group,
742 * whether they are isolcpus or were isolated via cpusets, lest
743 * the timer run on a CPU which does not service all runqueues,
744 * potentially leaving other CPUs indefinitely throttled. If
745 * isolation is really required, the user will turn the throttle
746 * off to kill the perturbations it causes anyway. Meanwhile,
747 * this maintains functionality for boot and/or troubleshooting.
749 if (rt_b == &root_task_group.rt_bandwidth)
750 span = cpu_online_mask;
752 for_each_cpu(i, span) {
754 struct rt_rq *rt_rq = sched_rt_period_rt_rq(rt_b, i);
755 struct rq *rq = rq_of_rt_rq(rt_rq);
757 raw_spin_lock(&rq->lock);
758 if (rt_rq->rt_time) {
761 raw_spin_lock(&rt_rq->rt_runtime_lock);
762 if (rt_rq->rt_throttled)
763 balance_runtime(rt_rq);
764 runtime = rt_rq->rt_runtime;
765 rt_rq->rt_time -= min(rt_rq->rt_time, overrun*runtime);
766 if (rt_rq->rt_throttled && rt_rq->rt_time < runtime) {
767 rt_rq->rt_throttled = 0;
771 * Force a clock update if the CPU was idle,
772 * lest wakeup -> unthrottle time accumulate.
774 if (rt_rq->rt_nr_running && rq->curr == rq->idle)
775 rq->skip_clock_update = -1;
777 if (rt_rq->rt_time || rt_rq->rt_nr_running)
779 raw_spin_unlock(&rt_rq->rt_runtime_lock);
780 } else if (rt_rq->rt_nr_running) {
782 if (!rt_rq_throttled(rt_rq))
785 if (rt_rq->rt_throttled)
789 sched_rt_rq_enqueue(rt_rq);
790 raw_spin_unlock(&rq->lock);
793 if (!throttled && (!rt_bandwidth_enabled() || rt_b->rt_runtime == RUNTIME_INF))
799 static inline int rt_se_prio(struct sched_rt_entity *rt_se)
801 #ifdef CONFIG_RT_GROUP_SCHED
802 struct rt_rq *rt_rq = group_rt_rq(rt_se);
805 return rt_rq->highest_prio.curr;
808 return rt_task_of(rt_se)->prio;
811 static int sched_rt_runtime_exceeded(struct rt_rq *rt_rq)
813 u64 runtime = sched_rt_runtime(rt_rq);
815 if (rt_rq->rt_throttled)
816 return rt_rq_throttled(rt_rq);
818 if (runtime >= sched_rt_period(rt_rq))
821 balance_runtime(rt_rq);
822 runtime = sched_rt_runtime(rt_rq);
823 if (runtime == RUNTIME_INF)
826 if (rt_rq->rt_time > runtime) {
827 struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
830 * Don't actually throttle groups that have no runtime assigned
831 * but accrue some time due to boosting.
833 if (likely(rt_b->rt_runtime)) {
834 static bool once = false;
836 rt_rq->rt_throttled = 1;
840 printk_sched("sched: RT throttling activated\n");
844 * In case we did anyway, make it go away,
845 * replenishment is a joke, since it will replenish us
851 if (rt_rq_throttled(rt_rq)) {
852 sched_rt_rq_dequeue(rt_rq);
861 * Update the current task's runtime statistics. Skip current tasks that
862 * are not in our scheduling class.
864 static void update_curr_rt(struct rq *rq)
866 struct task_struct *curr = rq->curr;
867 struct sched_rt_entity *rt_se = &curr->rt;
868 struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
871 if (curr->sched_class != &rt_sched_class)
874 delta_exec = rq_clock_task(rq) - curr->se.exec_start;
875 if (unlikely((s64)delta_exec <= 0))
878 schedstat_set(curr->se.statistics.exec_max,
879 max(curr->se.statistics.exec_max, delta_exec));
881 curr->se.sum_exec_runtime += delta_exec;
882 account_group_exec_runtime(curr, delta_exec);
884 curr->se.exec_start = rq_clock_task(rq);
885 cpuacct_charge(curr, delta_exec);
887 sched_rt_avg_update(rq, delta_exec);
889 if (!rt_bandwidth_enabled())
892 for_each_sched_rt_entity(rt_se) {
893 rt_rq = rt_rq_of_se(rt_se);
895 if (sched_rt_runtime(rt_rq) != RUNTIME_INF) {
896 raw_spin_lock(&rt_rq->rt_runtime_lock);
897 rt_rq->rt_time += delta_exec;
898 if (sched_rt_runtime_exceeded(rt_rq))
900 raw_spin_unlock(&rt_rq->rt_runtime_lock);
905 #if defined CONFIG_SMP
908 inc_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio)
910 struct rq *rq = rq_of_rt_rq(rt_rq);
912 #ifdef CONFIG_RT_GROUP_SCHED
914 * Change rq's cpupri only if rt_rq is the top queue.
916 if (&rq->rt != rt_rq)
919 if (rq->online && prio < prev_prio)
920 cpupri_set(&rq->rd->cpupri, rq->cpu, prio);
924 dec_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio)
926 struct rq *rq = rq_of_rt_rq(rt_rq);
928 #ifdef CONFIG_RT_GROUP_SCHED
930 * Change rq's cpupri only if rt_rq is the top queue.
932 if (&rq->rt != rt_rq)
935 if (rq->online && rt_rq->highest_prio.curr != prev_prio)
936 cpupri_set(&rq->rd->cpupri, rq->cpu, rt_rq->highest_prio.curr);
939 #else /* CONFIG_SMP */
942 void inc_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio) {}
944 void dec_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio) {}
946 #endif /* CONFIG_SMP */
948 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
950 inc_rt_prio(struct rt_rq *rt_rq, int prio)
952 int prev_prio = rt_rq->highest_prio.curr;
954 if (prio < prev_prio)
955 rt_rq->highest_prio.curr = prio;
957 inc_rt_prio_smp(rt_rq, prio, prev_prio);
961 dec_rt_prio(struct rt_rq *rt_rq, int prio)
963 int prev_prio = rt_rq->highest_prio.curr;
965 if (rt_rq->rt_nr_running) {
967 WARN_ON(prio < prev_prio);
970 * This may have been our highest task, and therefore
971 * we may have some recomputation to do
973 if (prio == prev_prio) {
974 struct rt_prio_array *array = &rt_rq->active;
976 rt_rq->highest_prio.curr =
977 sched_find_first_bit(array->bitmap);
981 rt_rq->highest_prio.curr = MAX_RT_PRIO;
983 dec_rt_prio_smp(rt_rq, prio, prev_prio);
988 static inline void inc_rt_prio(struct rt_rq *rt_rq, int prio) {}
989 static inline void dec_rt_prio(struct rt_rq *rt_rq, int prio) {}
991 #endif /* CONFIG_SMP || CONFIG_RT_GROUP_SCHED */
993 #ifdef CONFIG_RT_GROUP_SCHED
996 inc_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
998 if (rt_se_boosted(rt_se))
999 rt_rq->rt_nr_boosted++;
1002 start_rt_bandwidth(&rt_rq->tg->rt_bandwidth);
1006 dec_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
1008 if (rt_se_boosted(rt_se))
1009 rt_rq->rt_nr_boosted--;
1011 WARN_ON(!rt_rq->rt_nr_running && rt_rq->rt_nr_boosted);
1014 #else /* CONFIG_RT_GROUP_SCHED */
1017 inc_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
1019 start_rt_bandwidth(&def_rt_bandwidth);
1023 void dec_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) {}
1025 #endif /* CONFIG_RT_GROUP_SCHED */
1028 void inc_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
1030 int prio = rt_se_prio(rt_se);
1032 WARN_ON(!rt_prio(prio));
1033 rt_rq->rt_nr_running++;
1035 inc_rt_prio(rt_rq, prio);
1036 inc_rt_migration(rt_se, rt_rq);
1037 inc_rt_group(rt_se, rt_rq);
1041 void dec_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
1043 WARN_ON(!rt_prio(rt_se_prio(rt_se)));
1044 WARN_ON(!rt_rq->rt_nr_running);
1045 rt_rq->rt_nr_running--;
1047 dec_rt_prio(rt_rq, rt_se_prio(rt_se));
1048 dec_rt_migration(rt_se, rt_rq);
1049 dec_rt_group(rt_se, rt_rq);
1052 static void __enqueue_rt_entity(struct sched_rt_entity *rt_se, bool head)
1054 struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
1055 struct rt_prio_array *array = &rt_rq->active;
1056 struct rt_rq *group_rq = group_rt_rq(rt_se);
1057 struct list_head *queue = array->queue + rt_se_prio(rt_se);
1060 * Don't enqueue the group if its throttled, or when empty.
1061 * The latter is a consequence of the former when a child group
1062 * get throttled and the current group doesn't have any other
1065 if (group_rq && (rt_rq_throttled(group_rq) || !group_rq->rt_nr_running))
1069 list_add(&rt_se->run_list, queue);
1071 list_add_tail(&rt_se->run_list, queue);
1072 __set_bit(rt_se_prio(rt_se), array->bitmap);
1074 inc_rt_tasks(rt_se, rt_rq);
1077 static void __dequeue_rt_entity(struct sched_rt_entity *rt_se)
1079 struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
1080 struct rt_prio_array *array = &rt_rq->active;
1082 list_del_init(&rt_se->run_list);
1083 if (list_empty(array->queue + rt_se_prio(rt_se)))
1084 __clear_bit(rt_se_prio(rt_se), array->bitmap);
1086 dec_rt_tasks(rt_se, rt_rq);
1090 * Because the prio of an upper entry depends on the lower
1091 * entries, we must remove entries top - down.
1093 static void dequeue_rt_stack(struct sched_rt_entity *rt_se)
1095 struct sched_rt_entity *back = NULL;
1097 for_each_sched_rt_entity(rt_se) {
1102 for (rt_se = back; rt_se; rt_se = rt_se->back) {
1103 if (on_rt_rq(rt_se))
1104 __dequeue_rt_entity(rt_se);
1108 static void enqueue_rt_entity(struct sched_rt_entity *rt_se, bool head)
1110 dequeue_rt_stack(rt_se);
1111 for_each_sched_rt_entity(rt_se)
1112 __enqueue_rt_entity(rt_se, head);
1115 static void dequeue_rt_entity(struct sched_rt_entity *rt_se)
1117 dequeue_rt_stack(rt_se);
1119 for_each_sched_rt_entity(rt_se) {
1120 struct rt_rq *rt_rq = group_rt_rq(rt_se);
1122 if (rt_rq && rt_rq->rt_nr_running)
1123 __enqueue_rt_entity(rt_se, false);
1128 * Adding/removing a task to/from a priority array:
1131 enqueue_task_rt(struct rq *rq, struct task_struct *p, int flags)
1133 struct sched_rt_entity *rt_se = &p->rt;
1135 if (flags & ENQUEUE_WAKEUP)
1138 enqueue_rt_entity(rt_se, flags & ENQUEUE_HEAD);
1140 if (!task_current(rq, p) && p->nr_cpus_allowed > 1)
1141 enqueue_pushable_task(rq, p);
1146 static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int flags)
1148 struct sched_rt_entity *rt_se = &p->rt;
1151 dequeue_rt_entity(rt_se);
1153 dequeue_pushable_task(rq, p);
1159 * Put task to the head or the end of the run list without the overhead of
1160 * dequeue followed by enqueue.
1163 requeue_rt_entity(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se, int head)
1165 if (on_rt_rq(rt_se)) {
1166 struct rt_prio_array *array = &rt_rq->active;
1167 struct list_head *queue = array->queue + rt_se_prio(rt_se);
1170 list_move(&rt_se->run_list, queue);
1172 list_move_tail(&rt_se->run_list, queue);
1176 static void requeue_task_rt(struct rq *rq, struct task_struct *p, int head)
1178 struct sched_rt_entity *rt_se = &p->rt;
1179 struct rt_rq *rt_rq;
1181 for_each_sched_rt_entity(rt_se) {
1182 rt_rq = rt_rq_of_se(rt_se);
1183 requeue_rt_entity(rt_rq, rt_se, head);
1187 static void yield_task_rt(struct rq *rq)
1189 requeue_task_rt(rq, rq->curr, 0);
1193 static int find_lowest_rq(struct task_struct *task);
1196 select_task_rq_rt(struct task_struct *p, int cpu, int sd_flag, int flags)
1198 struct task_struct *curr;
1201 if (p->nr_cpus_allowed == 1)
1204 /* For anything but wake ups, just return the task_cpu */
1205 if (sd_flag != SD_BALANCE_WAKE && sd_flag != SD_BALANCE_FORK)
1211 curr = ACCESS_ONCE(rq->curr); /* unlocked access */
1214 * If the current task on @p's runqueue is an RT task, then
1215 * try to see if we can wake this RT task up on another
1216 * runqueue. Otherwise simply start this RT task
1217 * on its current runqueue.
1219 * We want to avoid overloading runqueues. If the woken
1220 * task is a higher priority, then it will stay on this CPU
1221 * and the lower prio task should be moved to another CPU.
1222 * Even though this will probably make the lower prio task
1223 * lose its cache, we do not want to bounce a higher task
1224 * around just because it gave up its CPU, perhaps for a
1227 * For equal prio tasks, we just let the scheduler sort it out.
1229 * Otherwise, just let it ride on the affined RQ and the
1230 * post-schedule router will push the preempted task away
1232 * This test is optimistic, if we get it wrong the load-balancer
1233 * will have to sort it out.
1235 if (curr && unlikely(rt_task(curr)) &&
1236 (curr->nr_cpus_allowed < 2 ||
1237 curr->prio <= p->prio)) {
1238 int target = find_lowest_rq(p);
1249 static void check_preempt_equal_prio(struct rq *rq, struct task_struct *p)
1251 if (rq->curr->nr_cpus_allowed == 1)
1254 if (p->nr_cpus_allowed != 1
1255 && cpupri_find(&rq->rd->cpupri, p, NULL))
1258 if (!cpupri_find(&rq->rd->cpupri, rq->curr, NULL))
1262 * There appears to be other cpus that can accept
1263 * current and none to run 'p', so lets reschedule
1264 * to try and push current away:
1266 requeue_task_rt(rq, p, 1);
1267 resched_task(rq->curr);
1270 #endif /* CONFIG_SMP */
1273 * Preempt the current task with a newly woken task if needed:
1275 static void check_preempt_curr_rt(struct rq *rq, struct task_struct *p, int flags)
1277 if (p->prio < rq->curr->prio) {
1278 resched_task(rq->curr);
1286 * - the newly woken task is of equal priority to the current task
1287 * - the newly woken task is non-migratable while current is migratable
1288 * - current will be preempted on the next reschedule
1290 * we should check to see if current can readily move to a different
1291 * cpu. If so, we will reschedule to allow the push logic to try
1292 * to move current somewhere else, making room for our non-migratable
1295 if (p->prio == rq->curr->prio && !test_tsk_need_resched(rq->curr))
1296 check_preempt_equal_prio(rq, p);
1300 static struct sched_rt_entity *pick_next_rt_entity(struct rq *rq,
1301 struct rt_rq *rt_rq)
1303 struct rt_prio_array *array = &rt_rq->active;
1304 struct sched_rt_entity *next = NULL;
1305 struct list_head *queue;
1308 idx = sched_find_first_bit(array->bitmap);
1309 BUG_ON(idx >= MAX_RT_PRIO);
1311 queue = array->queue + idx;
1312 next = list_entry(queue->next, struct sched_rt_entity, run_list);
1317 static struct task_struct *_pick_next_task_rt(struct rq *rq)
1319 struct sched_rt_entity *rt_se;
1320 struct task_struct *p;
1321 struct rt_rq *rt_rq;
1325 if (!rt_rq->rt_nr_running)
1328 if (rt_rq_throttled(rt_rq))
1332 rt_se = pick_next_rt_entity(rq, rt_rq);
1334 rt_rq = group_rt_rq(rt_se);
1337 p = rt_task_of(rt_se);
1338 p->se.exec_start = rq_clock_task(rq);
1343 static struct task_struct *pick_next_task_rt(struct rq *rq)
1345 struct task_struct *p = _pick_next_task_rt(rq);
1347 /* The running task is never eligible for pushing */
1349 dequeue_pushable_task(rq, p);
1353 * We detect this state here so that we can avoid taking the RQ
1354 * lock again later if there is no need to push
1356 rq->post_schedule = has_pushable_tasks(rq);
1362 static void put_prev_task_rt(struct rq *rq, struct task_struct *p)
1367 * The previous task needs to be made eligible for pushing
1368 * if it is still active
1370 if (on_rt_rq(&p->rt) && p->nr_cpus_allowed > 1)
1371 enqueue_pushable_task(rq, p);
1376 /* Only try algorithms three times */
1377 #define RT_MAX_TRIES 3
1379 static int pick_rt_task(struct rq *rq, struct task_struct *p, int cpu)
1381 if (!task_running(rq, p) &&
1382 cpumask_test_cpu(cpu, tsk_cpus_allowed(p)))
1388 * Return the highest pushable rq's task, which is suitable to be executed
1389 * on the cpu, NULL otherwise
1391 static struct task_struct *pick_highest_pushable_task(struct rq *rq, int cpu)
1393 struct plist_head *head = &rq->rt.pushable_tasks;
1394 struct task_struct *p;
1396 if (!has_pushable_tasks(rq))
1399 plist_for_each_entry(p, head, pushable_tasks) {
1400 if (pick_rt_task(rq, p, cpu))
1407 static DEFINE_PER_CPU(cpumask_var_t, local_cpu_mask);
1409 static int find_lowest_rq(struct task_struct *task)
1411 struct sched_domain *sd;
1412 struct cpumask *lowest_mask = __get_cpu_var(local_cpu_mask);
1413 int this_cpu = smp_processor_id();
1414 int cpu = task_cpu(task);
1416 /* Make sure the mask is initialized first */
1417 if (unlikely(!lowest_mask))
1420 if (task->nr_cpus_allowed == 1)
1421 return -1; /* No other targets possible */
1423 if (!cpupri_find(&task_rq(task)->rd->cpupri, task, lowest_mask))
1424 return -1; /* No targets found */
1427 * At this point we have built a mask of cpus representing the
1428 * lowest priority tasks in the system. Now we want to elect
1429 * the best one based on our affinity and topology.
1431 * We prioritize the last cpu that the task executed on since
1432 * it is most likely cache-hot in that location.
1434 if (cpumask_test_cpu(cpu, lowest_mask))
1438 * Otherwise, we consult the sched_domains span maps to figure
1439 * out which cpu is logically closest to our hot cache data.
1441 if (!cpumask_test_cpu(this_cpu, lowest_mask))
1442 this_cpu = -1; /* Skip this_cpu opt if not among lowest */
1445 for_each_domain(cpu, sd) {
1446 if (sd->flags & SD_WAKE_AFFINE) {
1450 * "this_cpu" is cheaper to preempt than a
1453 if (this_cpu != -1 &&
1454 cpumask_test_cpu(this_cpu, sched_domain_span(sd))) {
1459 best_cpu = cpumask_first_and(lowest_mask,
1460 sched_domain_span(sd));
1461 if (best_cpu < nr_cpu_ids) {
1470 * And finally, if there were no matches within the domains
1471 * just give the caller *something* to work with from the compatible
1477 cpu = cpumask_any(lowest_mask);
1478 if (cpu < nr_cpu_ids)
1483 /* Will lock the rq it finds */
1484 static struct rq *find_lock_lowest_rq(struct task_struct *task, struct rq *rq)
1486 struct rq *lowest_rq = NULL;
1490 for (tries = 0; tries < RT_MAX_TRIES; tries++) {
1491 cpu = find_lowest_rq(task);
1493 if ((cpu == -1) || (cpu == rq->cpu))
1496 lowest_rq = cpu_rq(cpu);
1498 /* if the prio of this runqueue changed, try again */
1499 if (double_lock_balance(rq, lowest_rq)) {
1501 * We had to unlock the run queue. In
1502 * the mean time, task could have
1503 * migrated already or had its affinity changed.
1504 * Also make sure that it wasn't scheduled on its rq.
1506 if (unlikely(task_rq(task) != rq ||
1507 !cpumask_test_cpu(lowest_rq->cpu,
1508 tsk_cpus_allowed(task)) ||
1509 task_running(rq, task) ||
1512 double_unlock_balance(rq, lowest_rq);
1518 /* If this rq is still suitable use it. */
1519 if (lowest_rq->rt.highest_prio.curr > task->prio)
1523 double_unlock_balance(rq, lowest_rq);
1530 static struct task_struct *pick_next_pushable_task(struct rq *rq)
1532 struct task_struct *p;
1534 if (!has_pushable_tasks(rq))
1537 p = plist_first_entry(&rq->rt.pushable_tasks,
1538 struct task_struct, pushable_tasks);
1540 BUG_ON(rq->cpu != task_cpu(p));
1541 BUG_ON(task_current(rq, p));
1542 BUG_ON(p->nr_cpus_allowed <= 1);
1545 BUG_ON(!rt_task(p));
1551 * If the current CPU has more than one RT task, see if the non
1552 * running task can migrate over to a CPU that is running a task
1553 * of lesser priority.
1555 static int push_rt_task(struct rq *rq)
1557 struct task_struct *next_task;
1558 struct rq *lowest_rq;
1561 if (!rq->rt.overloaded)
1564 next_task = pick_next_pushable_task(rq);
1569 if (unlikely(next_task == rq->curr)) {
1575 * It's possible that the next_task slipped in of
1576 * higher priority than current. If that's the case
1577 * just reschedule current.
1579 if (unlikely(next_task->prio < rq->curr->prio)) {
1580 resched_task(rq->curr);
1584 /* We might release rq lock */
1585 get_task_struct(next_task);
1587 /* find_lock_lowest_rq locks the rq if found */
1588 lowest_rq = find_lock_lowest_rq(next_task, rq);
1590 struct task_struct *task;
1592 * find_lock_lowest_rq releases rq->lock
1593 * so it is possible that next_task has migrated.
1595 * We need to make sure that the task is still on the same
1596 * run-queue and is also still the next task eligible for
1599 task = pick_next_pushable_task(rq);
1600 if (task_cpu(next_task) == rq->cpu && task == next_task) {
1602 * The task hasn't migrated, and is still the next
1603 * eligible task, but we failed to find a run-queue
1604 * to push it to. Do not retry in this case, since
1605 * other cpus will pull from us when ready.
1611 /* No more tasks, just exit */
1615 * Something has shifted, try again.
1617 put_task_struct(next_task);
1622 deactivate_task(rq, next_task, 0);
1623 set_task_cpu(next_task, lowest_rq->cpu);
1624 activate_task(lowest_rq, next_task, 0);
1627 resched_task(lowest_rq->curr);
1629 double_unlock_balance(rq, lowest_rq);
1632 put_task_struct(next_task);
1637 static void push_rt_tasks(struct rq *rq)
1639 /* push_rt_task will return true if it moved an RT */
1640 while (push_rt_task(rq))
1644 static int pull_rt_task(struct rq *this_rq)
1646 int this_cpu = this_rq->cpu, ret = 0, cpu;
1647 struct task_struct *p;
1650 if (likely(!rt_overloaded(this_rq)))
1654 * Match the barrier from rt_set_overloaded; this guarantees that if we
1655 * see overloaded we must also see the rto_mask bit.
1659 for_each_cpu(cpu, this_rq->rd->rto_mask) {
1660 if (this_cpu == cpu)
1663 src_rq = cpu_rq(cpu);
1666 * Don't bother taking the src_rq->lock if the next highest
1667 * task is known to be lower-priority than our current task.
1668 * This may look racy, but if this value is about to go
1669 * logically higher, the src_rq will push this task away.
1670 * And if its going logically lower, we do not care
1672 if (src_rq->rt.highest_prio.next >=
1673 this_rq->rt.highest_prio.curr)
1677 * We can potentially drop this_rq's lock in
1678 * double_lock_balance, and another CPU could
1681 double_lock_balance(this_rq, src_rq);
1684 * We can pull only a task, which is pushable
1685 * on its rq, and no others.
1687 p = pick_highest_pushable_task(src_rq, this_cpu);
1690 * Do we have an RT task that preempts
1691 * the to-be-scheduled task?
1693 if (p && (p->prio < this_rq->rt.highest_prio.curr)) {
1694 WARN_ON(p == src_rq->curr);
1698 * There's a chance that p is higher in priority
1699 * than what's currently running on its cpu.
1700 * This is just that p is wakeing up and hasn't
1701 * had a chance to schedule. We only pull
1702 * p if it is lower in priority than the
1703 * current task on the run queue
1705 if (p->prio < src_rq->curr->prio)
1710 deactivate_task(src_rq, p, 0);
1711 set_task_cpu(p, this_cpu);
1712 activate_task(this_rq, p, 0);
1714 * We continue with the search, just in
1715 * case there's an even higher prio task
1716 * in another runqueue. (low likelihood
1721 double_unlock_balance(this_rq, src_rq);
1727 static void pre_schedule_rt(struct rq *rq, struct task_struct *prev)
1729 /* Try to pull RT tasks here if we lower this rq's prio */
1730 if (rq->rt.highest_prio.curr > prev->prio)
1734 static void post_schedule_rt(struct rq *rq)
1740 * If we are not running and we are not going to reschedule soon, we should
1741 * try to push tasks away now
1743 static void task_woken_rt(struct rq *rq, struct task_struct *p)
1745 if (!task_running(rq, p) &&
1746 !test_tsk_need_resched(rq->curr) &&
1747 has_pushable_tasks(rq) &&
1748 p->nr_cpus_allowed > 1 &&
1749 (dl_task(rq->curr) || rt_task(rq->curr)) &&
1750 (rq->curr->nr_cpus_allowed < 2 ||
1751 rq->curr->prio <= p->prio))
1755 static void set_cpus_allowed_rt(struct task_struct *p,
1756 const struct cpumask *new_mask)
1761 BUG_ON(!rt_task(p));
1766 weight = cpumask_weight(new_mask);
1769 * Only update if the process changes its state from whether it
1770 * can migrate or not.
1772 if ((p->nr_cpus_allowed > 1) == (weight > 1))
1778 * The process used to be able to migrate OR it can now migrate
1781 if (!task_current(rq, p))
1782 dequeue_pushable_task(rq, p);
1783 BUG_ON(!rq->rt.rt_nr_migratory);
1784 rq->rt.rt_nr_migratory--;
1786 if (!task_current(rq, p))
1787 enqueue_pushable_task(rq, p);
1788 rq->rt.rt_nr_migratory++;
1791 update_rt_migration(&rq->rt);
1794 /* Assumes rq->lock is held */
1795 static void rq_online_rt(struct rq *rq)
1797 if (rq->rt.overloaded)
1798 rt_set_overload(rq);
1800 __enable_runtime(rq);
1802 cpupri_set(&rq->rd->cpupri, rq->cpu, rq->rt.highest_prio.curr);
1805 /* Assumes rq->lock is held */
1806 static void rq_offline_rt(struct rq *rq)
1808 if (rq->rt.overloaded)
1809 rt_clear_overload(rq);
1811 __disable_runtime(rq);
1813 cpupri_set(&rq->rd->cpupri, rq->cpu, CPUPRI_INVALID);
1817 * When switch from the rt queue, we bring ourselves to a position
1818 * that we might want to pull RT tasks from other runqueues.
1820 static void switched_from_rt(struct rq *rq, struct task_struct *p)
1823 * If there are other RT tasks then we will reschedule
1824 * and the scheduling of the other RT tasks will handle
1825 * the balancing. But if we are the last RT task
1826 * we may need to handle the pulling of RT tasks
1829 if (!p->on_rq || rq->rt.rt_nr_running)
1832 if (pull_rt_task(rq))
1833 resched_task(rq->curr);
1836 void init_sched_rt_class(void)
1840 for_each_possible_cpu(i) {
1841 zalloc_cpumask_var_node(&per_cpu(local_cpu_mask, i),
1842 GFP_KERNEL, cpu_to_node(i));
1845 #endif /* CONFIG_SMP */
1848 * When switching a task to RT, we may overload the runqueue
1849 * with RT tasks. In this case we try to push them off to
1852 static void switched_to_rt(struct rq *rq, struct task_struct *p)
1854 int check_resched = 1;
1857 * If we are already running, then there's nothing
1858 * that needs to be done. But if we are not running
1859 * we may need to preempt the current running task.
1860 * If that current running task is also an RT task
1861 * then see if we can move to another run queue.
1863 if (p->on_rq && rq->curr != p) {
1865 if (rq->rt.overloaded && push_rt_task(rq) &&
1866 /* Don't resched if we changed runqueues */
1869 #endif /* CONFIG_SMP */
1870 if (check_resched && p->prio < rq->curr->prio)
1871 resched_task(rq->curr);
1876 * Priority of the task has changed. This may cause
1877 * us to initiate a push or pull.
1880 prio_changed_rt(struct rq *rq, struct task_struct *p, int oldprio)
1885 if (rq->curr == p) {
1888 * If our priority decreases while running, we
1889 * may need to pull tasks to this runqueue.
1891 if (oldprio < p->prio)
1894 * If there's a higher priority task waiting to run
1895 * then reschedule. Note, the above pull_rt_task
1896 * can release the rq lock and p could migrate.
1897 * Only reschedule if p is still on the same runqueue.
1899 if (p->prio > rq->rt.highest_prio.curr && rq->curr == p)
1902 /* For UP simply resched on drop of prio */
1903 if (oldprio < p->prio)
1905 #endif /* CONFIG_SMP */
1908 * This task is not running, but if it is
1909 * greater than the current running task
1912 if (p->prio < rq->curr->prio)
1913 resched_task(rq->curr);
1917 static void watchdog(struct rq *rq, struct task_struct *p)
1919 unsigned long soft, hard;
1921 /* max may change after cur was read, this will be fixed next tick */
1922 soft = task_rlimit(p, RLIMIT_RTTIME);
1923 hard = task_rlimit_max(p, RLIMIT_RTTIME);
1925 if (soft != RLIM_INFINITY) {
1928 if (p->rt.watchdog_stamp != jiffies) {
1930 p->rt.watchdog_stamp = jiffies;
1933 next = DIV_ROUND_UP(min(soft, hard), USEC_PER_SEC/HZ);
1934 if (p->rt.timeout > next)
1935 p->cputime_expires.sched_exp = p->se.sum_exec_runtime;
1939 static void task_tick_rt(struct rq *rq, struct task_struct *p, int queued)
1941 struct sched_rt_entity *rt_se = &p->rt;
1948 * RR tasks need a special form of timeslice management.
1949 * FIFO tasks have no timeslices.
1951 if (p->policy != SCHED_RR)
1954 if (--p->rt.time_slice)
1957 p->rt.time_slice = sched_rr_timeslice;
1960 * Requeue to the end of queue if we (and all of our ancestors) are not
1961 * the only element on the queue
1963 for_each_sched_rt_entity(rt_se) {
1964 if (rt_se->run_list.prev != rt_se->run_list.next) {
1965 requeue_task_rt(rq, p, 0);
1966 set_tsk_need_resched(p);
1972 static void set_curr_task_rt(struct rq *rq)
1974 struct task_struct *p = rq->curr;
1976 p->se.exec_start = rq_clock_task(rq);
1978 /* The running task is never eligible for pushing */
1979 dequeue_pushable_task(rq, p);
1982 static unsigned int get_rr_interval_rt(struct rq *rq, struct task_struct *task)
1985 * Time slice is 0 for SCHED_FIFO tasks
1987 if (task->policy == SCHED_RR)
1988 return sched_rr_timeslice;
1993 const struct sched_class rt_sched_class = {
1994 .next = &fair_sched_class,
1995 .enqueue_task = enqueue_task_rt,
1996 .dequeue_task = dequeue_task_rt,
1997 .yield_task = yield_task_rt,
1999 .check_preempt_curr = check_preempt_curr_rt,
2001 .pick_next_task = pick_next_task_rt,
2002 .put_prev_task = put_prev_task_rt,
2005 .select_task_rq = select_task_rq_rt,
2007 .set_cpus_allowed = set_cpus_allowed_rt,
2008 .rq_online = rq_online_rt,
2009 .rq_offline = rq_offline_rt,
2010 .pre_schedule = pre_schedule_rt,
2011 .post_schedule = post_schedule_rt,
2012 .task_woken = task_woken_rt,
2013 .switched_from = switched_from_rt,
2016 .set_curr_task = set_curr_task_rt,
2017 .task_tick = task_tick_rt,
2019 .get_rr_interval = get_rr_interval_rt,
2021 .prio_changed = prio_changed_rt,
2022 .switched_to = switched_to_rt,
2025 #ifdef CONFIG_SCHED_DEBUG
2026 extern void print_rt_rq(struct seq_file *m, int cpu, struct rt_rq *rt_rq);
2028 void print_rt_stats(struct seq_file *m, int cpu)
2031 struct rt_rq *rt_rq;
2034 for_each_rt_rq(rt_rq, iter, cpu_rq(cpu))
2035 print_rt_rq(m, cpu, rt_rq);
2038 #endif /* CONFIG_SCHED_DEBUG */