2 * Deadline Scheduling Class (SCHED_DEADLINE)
4 * Earliest Deadline First (EDF) + Constant Bandwidth Server (CBS).
6 * Tasks that periodically executes their instances for less than their
7 * runtime won't miss any of their deadlines.
8 * Tasks that are not periodic or sporadic or that tries to execute more
9 * than their reserved bandwidth will be slowed down (and may potentially
10 * miss some of their deadlines), and won't affect any other task.
12 * Copyright (C) 2012 Dario Faggioli <raistlin@linux.it>,
13 * Juri Lelli <juri.lelli@gmail.com>,
14 * Michael Trimarchi <michael@amarulasolutions.com>,
15 * Fabio Checconi <fchecconi@gmail.com>
19 #include <linux/slab.h>
21 struct dl_bandwidth def_dl_bandwidth;
23 static inline struct task_struct *dl_task_of(struct sched_dl_entity *dl_se)
25 return container_of(dl_se, struct task_struct, dl);
28 static inline struct rq *rq_of_dl_rq(struct dl_rq *dl_rq)
30 return container_of(dl_rq, struct rq, dl);
33 static inline struct dl_rq *dl_rq_of_se(struct sched_dl_entity *dl_se)
35 struct task_struct *p = dl_task_of(dl_se);
36 struct rq *rq = task_rq(p);
41 static inline int on_dl_rq(struct sched_dl_entity *dl_se)
43 return !RB_EMPTY_NODE(&dl_se->rb_node);
46 static inline int is_leftmost(struct task_struct *p, struct dl_rq *dl_rq)
48 struct sched_dl_entity *dl_se = &p->dl;
50 return dl_rq->rb_leftmost == &dl_se->rb_node;
53 void init_dl_bandwidth(struct dl_bandwidth *dl_b, u64 period, u64 runtime)
55 raw_spin_lock_init(&dl_b->dl_runtime_lock);
56 dl_b->dl_period = period;
57 dl_b->dl_runtime = runtime;
60 void init_dl_bw(struct dl_bw *dl_b)
62 raw_spin_lock_init(&dl_b->lock);
63 raw_spin_lock(&def_dl_bandwidth.dl_runtime_lock);
64 if (global_rt_runtime() == RUNTIME_INF)
67 dl_b->bw = to_ratio(global_rt_period(), global_rt_runtime());
68 raw_spin_unlock(&def_dl_bandwidth.dl_runtime_lock);
72 void init_dl_rq(struct dl_rq *dl_rq)
74 dl_rq->rb_root = RB_ROOT;
77 /* zero means no -deadline tasks */
78 dl_rq->earliest_dl.curr = dl_rq->earliest_dl.next = 0;
80 dl_rq->dl_nr_migratory = 0;
81 dl_rq->overloaded = 0;
82 dl_rq->pushable_dl_tasks_root = RB_ROOT;
84 init_dl_bw(&dl_rq->dl_bw);
90 static inline int dl_overloaded(struct rq *rq)
92 return atomic_read(&rq->rd->dlo_count);
95 static inline void dl_set_overload(struct rq *rq)
100 cpumask_set_cpu(rq->cpu, rq->rd->dlo_mask);
102 * Must be visible before the overload count is
103 * set (as in sched_rt.c).
105 * Matched by the barrier in pull_dl_task().
108 atomic_inc(&rq->rd->dlo_count);
111 static inline void dl_clear_overload(struct rq *rq)
116 atomic_dec(&rq->rd->dlo_count);
117 cpumask_clear_cpu(rq->cpu, rq->rd->dlo_mask);
120 static void update_dl_migration(struct dl_rq *dl_rq)
122 if (dl_rq->dl_nr_migratory && dl_rq->dl_nr_running > 1) {
123 if (!dl_rq->overloaded) {
124 dl_set_overload(rq_of_dl_rq(dl_rq));
125 dl_rq->overloaded = 1;
127 } else if (dl_rq->overloaded) {
128 dl_clear_overload(rq_of_dl_rq(dl_rq));
129 dl_rq->overloaded = 0;
133 static void inc_dl_migration(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq)
135 struct task_struct *p = dl_task_of(dl_se);
137 if (p->nr_cpus_allowed > 1)
138 dl_rq->dl_nr_migratory++;
140 update_dl_migration(dl_rq);
143 static void dec_dl_migration(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq)
145 struct task_struct *p = dl_task_of(dl_se);
147 if (p->nr_cpus_allowed > 1)
148 dl_rq->dl_nr_migratory--;
150 update_dl_migration(dl_rq);
154 * The list of pushable -deadline task is not a plist, like in
155 * sched_rt.c, it is an rb-tree with tasks ordered by deadline.
157 static void enqueue_pushable_dl_task(struct rq *rq, struct task_struct *p)
159 struct dl_rq *dl_rq = &rq->dl;
160 struct rb_node **link = &dl_rq->pushable_dl_tasks_root.rb_node;
161 struct rb_node *parent = NULL;
162 struct task_struct *entry;
165 BUG_ON(!RB_EMPTY_NODE(&p->pushable_dl_tasks));
169 entry = rb_entry(parent, struct task_struct,
171 if (dl_entity_preempt(&p->dl, &entry->dl))
172 link = &parent->rb_left;
174 link = &parent->rb_right;
180 dl_rq->pushable_dl_tasks_leftmost = &p->pushable_dl_tasks;
182 rb_link_node(&p->pushable_dl_tasks, parent, link);
183 rb_insert_color(&p->pushable_dl_tasks, &dl_rq->pushable_dl_tasks_root);
186 static void dequeue_pushable_dl_task(struct rq *rq, struct task_struct *p)
188 struct dl_rq *dl_rq = &rq->dl;
190 if (RB_EMPTY_NODE(&p->pushable_dl_tasks))
193 if (dl_rq->pushable_dl_tasks_leftmost == &p->pushable_dl_tasks) {
194 struct rb_node *next_node;
196 next_node = rb_next(&p->pushable_dl_tasks);
197 dl_rq->pushable_dl_tasks_leftmost = next_node;
200 rb_erase(&p->pushable_dl_tasks, &dl_rq->pushable_dl_tasks_root);
201 RB_CLEAR_NODE(&p->pushable_dl_tasks);
204 static inline int has_pushable_dl_tasks(struct rq *rq)
206 return !RB_EMPTY_ROOT(&rq->dl.pushable_dl_tasks_root);
209 static int push_dl_task(struct rq *rq);
211 static inline bool need_pull_dl_task(struct rq *rq, struct task_struct *prev)
213 return dl_task(prev);
216 static inline void set_post_schedule(struct rq *rq)
218 rq->post_schedule = has_pushable_dl_tasks(rq);
224 void enqueue_pushable_dl_task(struct rq *rq, struct task_struct *p)
229 void dequeue_pushable_dl_task(struct rq *rq, struct task_struct *p)
234 void inc_dl_migration(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq)
239 void dec_dl_migration(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq)
243 static inline bool need_pull_dl_task(struct rq *rq, struct task_struct *prev)
248 static inline int pull_dl_task(struct rq *rq)
253 static inline void set_post_schedule(struct rq *rq)
256 #endif /* CONFIG_SMP */
258 static void enqueue_task_dl(struct rq *rq, struct task_struct *p, int flags);
259 static void __dequeue_task_dl(struct rq *rq, struct task_struct *p, int flags);
260 static void check_preempt_curr_dl(struct rq *rq, struct task_struct *p,
264 * We are being explicitly informed that a new instance is starting,
265 * and this means that:
266 * - the absolute deadline of the entity has to be placed at
267 * current time + relative deadline;
268 * - the runtime of the entity has to be set to the maximum value.
270 * The capability of specifying such event is useful whenever a -deadline
271 * entity wants to (try to!) synchronize its behaviour with the scheduler's
272 * one, and to (try to!) reconcile itself with its own scheduling
275 static inline void setup_new_dl_entity(struct sched_dl_entity *dl_se,
276 struct sched_dl_entity *pi_se)
278 struct dl_rq *dl_rq = dl_rq_of_se(dl_se);
279 struct rq *rq = rq_of_dl_rq(dl_rq);
281 WARN_ON(!dl_se->dl_new || dl_se->dl_throttled);
284 * We use the regular wall clock time to set deadlines in the
285 * future; in fact, we must consider execution overheads (time
286 * spent on hardirq context, etc.).
288 dl_se->deadline = rq_clock(rq) + pi_se->dl_deadline;
289 dl_se->runtime = pi_se->dl_runtime;
294 * Pure Earliest Deadline First (EDF) scheduling does not deal with the
295 * possibility of a entity lasting more than what it declared, and thus
296 * exhausting its runtime.
298 * Here we are interested in making runtime overrun possible, but we do
299 * not want a entity which is misbehaving to affect the scheduling of all
301 * Therefore, a budgeting strategy called Constant Bandwidth Server (CBS)
302 * is used, in order to confine each entity within its own bandwidth.
304 * This function deals exactly with that, and ensures that when the runtime
305 * of a entity is replenished, its deadline is also postponed. That ensures
306 * the overrunning entity can't interfere with other entity in the system and
307 * can't make them miss their deadlines. Reasons why this kind of overruns
308 * could happen are, typically, a entity voluntarily trying to overcome its
309 * runtime, or it just underestimated it during sched_setattr().
311 static void replenish_dl_entity(struct sched_dl_entity *dl_se,
312 struct sched_dl_entity *pi_se)
314 struct dl_rq *dl_rq = dl_rq_of_se(dl_se);
315 struct rq *rq = rq_of_dl_rq(dl_rq);
317 BUG_ON(pi_se->dl_runtime <= 0);
320 * This could be the case for a !-dl task that is boosted.
321 * Just go with full inherited parameters.
323 if (dl_se->dl_deadline == 0) {
324 dl_se->deadline = rq_clock(rq) + pi_se->dl_deadline;
325 dl_se->runtime = pi_se->dl_runtime;
329 * We keep moving the deadline away until we get some
330 * available runtime for the entity. This ensures correct
331 * handling of situations where the runtime overrun is
334 while (dl_se->runtime <= 0) {
335 dl_se->deadline += pi_se->dl_period;
336 dl_se->runtime += pi_se->dl_runtime;
340 * At this point, the deadline really should be "in
341 * the future" with respect to rq->clock. If it's
342 * not, we are, for some reason, lagging too much!
343 * Anyway, after having warn userspace abut that,
344 * we still try to keep the things running by
345 * resetting the deadline and the budget of the
348 if (dl_time_before(dl_se->deadline, rq_clock(rq))) {
349 printk_deferred_once("sched: DL replenish lagged to much\n");
350 dl_se->deadline = rq_clock(rq) + pi_se->dl_deadline;
351 dl_se->runtime = pi_se->dl_runtime;
354 if (dl_se->dl_yielded)
355 dl_se->dl_yielded = 0;
356 if (dl_se->dl_throttled)
357 dl_se->dl_throttled = 0;
361 * Here we check if --at time t-- an entity (which is probably being
362 * [re]activated or, in general, enqueued) can use its remaining runtime
363 * and its current deadline _without_ exceeding the bandwidth it is
364 * assigned (function returns true if it can't). We are in fact applying
365 * one of the CBS rules: when a task wakes up, if the residual runtime
366 * over residual deadline fits within the allocated bandwidth, then we
367 * can keep the current (absolute) deadline and residual budget without
368 * disrupting the schedulability of the system. Otherwise, we should
369 * refill the runtime and set the deadline a period in the future,
370 * because keeping the current (absolute) deadline of the task would
371 * result in breaking guarantees promised to other tasks (refer to
372 * Documentation/scheduler/sched-deadline.txt for more informations).
374 * This function returns true if:
376 * runtime / (deadline - t) > dl_runtime / dl_period ,
378 * IOW we can't recycle current parameters.
380 * Notice that the bandwidth check is done against the period. For
381 * task with deadline equal to period this is the same of using
382 * dl_deadline instead of dl_period in the equation above.
384 static bool dl_entity_overflow(struct sched_dl_entity *dl_se,
385 struct sched_dl_entity *pi_se, u64 t)
390 * left and right are the two sides of the equation above,
391 * after a bit of shuffling to use multiplications instead
394 * Note that none of the time values involved in the two
395 * multiplications are absolute: dl_deadline and dl_runtime
396 * are the relative deadline and the maximum runtime of each
397 * instance, runtime is the runtime left for the last instance
398 * and (deadline - t), since t is rq->clock, is the time left
399 * to the (absolute) deadline. Even if overflowing the u64 type
400 * is very unlikely to occur in both cases, here we scale down
401 * as we want to avoid that risk at all. Scaling down by 10
402 * means that we reduce granularity to 1us. We are fine with it,
403 * since this is only a true/false check and, anyway, thinking
404 * of anything below microseconds resolution is actually fiction
405 * (but still we want to give the user that illusion >;).
407 left = (pi_se->dl_period >> DL_SCALE) * (dl_se->runtime >> DL_SCALE);
408 right = ((dl_se->deadline - t) >> DL_SCALE) *
409 (pi_se->dl_runtime >> DL_SCALE);
411 return dl_time_before(right, left);
415 * When a -deadline entity is queued back on the runqueue, its runtime and
416 * deadline might need updating.
418 * The policy here is that we update the deadline of the entity only if:
419 * - the current deadline is in the past,
420 * - using the remaining runtime with the current deadline would make
421 * the entity exceed its bandwidth.
423 static void update_dl_entity(struct sched_dl_entity *dl_se,
424 struct sched_dl_entity *pi_se)
426 struct dl_rq *dl_rq = dl_rq_of_se(dl_se);
427 struct rq *rq = rq_of_dl_rq(dl_rq);
430 * The arrival of a new instance needs special treatment, i.e.,
431 * the actual scheduling parameters have to be "renewed".
434 setup_new_dl_entity(dl_se, pi_se);
438 if (dl_time_before(dl_se->deadline, rq_clock(rq)) ||
439 dl_entity_overflow(dl_se, pi_se, rq_clock(rq))) {
440 dl_se->deadline = rq_clock(rq) + pi_se->dl_deadline;
441 dl_se->runtime = pi_se->dl_runtime;
446 * If the entity depleted all its runtime, and if we want it to sleep
447 * while waiting for some new execution time to become available, we
448 * set the bandwidth enforcement timer to the replenishment instant
449 * and try to activate it.
451 * Notice that it is important for the caller to know if the timer
452 * actually started or not (i.e., the replenishment instant is in
453 * the future or in the past).
455 static int start_dl_timer(struct sched_dl_entity *dl_se, bool boosted)
457 struct dl_rq *dl_rq = dl_rq_of_se(dl_se);
458 struct rq *rq = rq_of_dl_rq(dl_rq);
467 * We want the timer to fire at the deadline, but considering
468 * that it is actually coming from rq->clock and not from
469 * hrtimer's time base reading.
471 act = ns_to_ktime(dl_se->deadline);
472 now = hrtimer_cb_get_time(&dl_se->dl_timer);
473 delta = ktime_to_ns(now) - rq_clock(rq);
474 act = ktime_add_ns(act, delta);
477 * If the expiry time already passed, e.g., because the value
478 * chosen as the deadline is too small, don't even try to
479 * start the timer in the past!
481 if (ktime_us_delta(act, now) < 0)
484 hrtimer_set_expires(&dl_se->dl_timer, act);
486 soft = hrtimer_get_softexpires(&dl_se->dl_timer);
487 hard = hrtimer_get_expires(&dl_se->dl_timer);
488 range = ktime_to_ns(ktime_sub(hard, soft));
489 __hrtimer_start_range_ns(&dl_se->dl_timer, soft,
490 range, HRTIMER_MODE_ABS, 0);
492 return hrtimer_active(&dl_se->dl_timer);
496 * This is the bandwidth enforcement timer callback. If here, we know
497 * a task is not on its dl_rq, since the fact that the timer was running
498 * means the task is throttled and needs a runtime replenishment.
500 * However, what we actually do depends on the fact the task is active,
501 * (it is on its rq) or has been removed from there by a call to
502 * dequeue_task_dl(). In the former case we must issue the runtime
503 * replenishment and add the task back to the dl_rq; in the latter, we just
504 * do nothing but clearing dl_throttled, so that runtime and deadline
505 * updating (and the queueing back to dl_rq) will be done by the
506 * next call to enqueue_task_dl().
508 static enum hrtimer_restart dl_task_timer(struct hrtimer *timer)
510 struct sched_dl_entity *dl_se = container_of(timer,
511 struct sched_dl_entity,
513 struct task_struct *p = dl_task_of(dl_se);
517 rq = task_rq_lock(current, &flags);
520 * We need to take care of several possible races here:
522 * - the task might have changed its scheduling policy
523 * to something different than SCHED_DEADLINE
524 * - the task might have changed its reservation parameters
525 * (through sched_setattr())
526 * - the task might have been boosted by someone else and
527 * might be in the boosting/deboosting path
529 * In all this cases we bail out, as the task is already
530 * in the runqueue or is going to be enqueued back anyway.
532 if (!dl_task(p) || dl_se->dl_new ||
533 dl_se->dl_boosted || !dl_se->dl_throttled)
540 * If the throttle happened during sched-out; like:
547 * __dequeue_task_dl()
550 * We can be both throttled and !queued. Replenish the counter
551 * but do not enqueue -- wait for our wakeup to do that.
553 if (!task_on_rq_queued(p)) {
554 replenish_dl_entity(dl_se, dl_se);
558 enqueue_task_dl(rq, p, ENQUEUE_REPLENISH);
559 if (dl_task(rq->curr))
560 check_preempt_curr_dl(rq, p, 0);
565 * Queueing this task back might have overloaded rq,
566 * check if we need to kick someone away.
568 if (has_pushable_dl_tasks(rq))
572 task_rq_unlock(rq, current, &flags);
574 return HRTIMER_NORESTART;
577 void init_dl_task_timer(struct sched_dl_entity *dl_se)
579 struct hrtimer *timer = &dl_se->dl_timer;
581 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
582 timer->function = dl_task_timer;
586 int dl_runtime_exceeded(struct rq *rq, struct sched_dl_entity *dl_se)
588 return (dl_se->runtime <= 0);
591 extern bool sched_rt_bandwidth_account(struct rt_rq *rt_rq);
594 * Update the current task's runtime statistics (provided it is still
595 * a -deadline task and has not been removed from the dl_rq).
597 static void update_curr_dl(struct rq *rq)
599 struct task_struct *curr = rq->curr;
600 struct sched_dl_entity *dl_se = &curr->dl;
603 if (!dl_task(curr) || !on_dl_rq(dl_se))
607 * Consumed budget is computed considering the time as
608 * observed by schedulable tasks (excluding time spent
609 * in hardirq context, etc.). Deadlines are instead
610 * computed using hard walltime. This seems to be the more
611 * natural solution, but the full ramifications of this
612 * approach need further study.
614 delta_exec = rq_clock_task(rq) - curr->se.exec_start;
615 if (unlikely((s64)delta_exec <= 0))
618 schedstat_set(curr->se.statistics.exec_max,
619 max(curr->se.statistics.exec_max, delta_exec));
621 curr->se.sum_exec_runtime += delta_exec;
622 account_group_exec_runtime(curr, delta_exec);
624 curr->se.exec_start = rq_clock_task(rq);
625 cpuacct_charge(curr, delta_exec);
627 sched_rt_avg_update(rq, delta_exec);
629 dl_se->runtime -= dl_se->dl_yielded ? 0 : delta_exec;
630 if (dl_runtime_exceeded(rq, dl_se)) {
631 dl_se->dl_throttled = 1;
632 __dequeue_task_dl(rq, curr, 0);
633 if (unlikely(!start_dl_timer(dl_se, curr->dl.dl_boosted)))
634 enqueue_task_dl(rq, curr, ENQUEUE_REPLENISH);
636 if (!is_leftmost(curr, &rq->dl))
641 * Because -- for now -- we share the rt bandwidth, we need to
642 * account our runtime there too, otherwise actual rt tasks
643 * would be able to exceed the shared quota.
645 * Account to the root rt group for now.
647 * The solution we're working towards is having the RT groups scheduled
648 * using deadline servers -- however there's a few nasties to figure
649 * out before that can happen.
651 if (rt_bandwidth_enabled()) {
652 struct rt_rq *rt_rq = &rq->rt;
654 raw_spin_lock(&rt_rq->rt_runtime_lock);
656 * We'll let actual RT tasks worry about the overflow here, we
657 * have our own CBS to keep us inline; only account when RT
658 * bandwidth is relevant.
660 if (sched_rt_bandwidth_account(rt_rq))
661 rt_rq->rt_time += delta_exec;
662 raw_spin_unlock(&rt_rq->rt_runtime_lock);
668 static struct task_struct *pick_next_earliest_dl_task(struct rq *rq, int cpu);
670 static inline u64 next_deadline(struct rq *rq)
672 struct task_struct *next = pick_next_earliest_dl_task(rq, rq->cpu);
674 if (next && dl_prio(next->prio))
675 return next->dl.deadline;
680 static void inc_dl_deadline(struct dl_rq *dl_rq, u64 deadline)
682 struct rq *rq = rq_of_dl_rq(dl_rq);
684 if (dl_rq->earliest_dl.curr == 0 ||
685 dl_time_before(deadline, dl_rq->earliest_dl.curr)) {
687 * If the dl_rq had no -deadline tasks, or if the new task
688 * has shorter deadline than the current one on dl_rq, we
689 * know that the previous earliest becomes our next earliest,
690 * as the new task becomes the earliest itself.
692 dl_rq->earliest_dl.next = dl_rq->earliest_dl.curr;
693 dl_rq->earliest_dl.curr = deadline;
694 cpudl_set(&rq->rd->cpudl, rq->cpu, deadline, 1);
695 } else if (dl_rq->earliest_dl.next == 0 ||
696 dl_time_before(deadline, dl_rq->earliest_dl.next)) {
698 * On the other hand, if the new -deadline task has a
699 * a later deadline than the earliest one on dl_rq, but
700 * it is earlier than the next (if any), we must
701 * recompute the next-earliest.
703 dl_rq->earliest_dl.next = next_deadline(rq);
707 static void dec_dl_deadline(struct dl_rq *dl_rq, u64 deadline)
709 struct rq *rq = rq_of_dl_rq(dl_rq);
712 * Since we may have removed our earliest (and/or next earliest)
713 * task we must recompute them.
715 if (!dl_rq->dl_nr_running) {
716 dl_rq->earliest_dl.curr = 0;
717 dl_rq->earliest_dl.next = 0;
718 cpudl_set(&rq->rd->cpudl, rq->cpu, 0, 0);
720 struct rb_node *leftmost = dl_rq->rb_leftmost;
721 struct sched_dl_entity *entry;
723 entry = rb_entry(leftmost, struct sched_dl_entity, rb_node);
724 dl_rq->earliest_dl.curr = entry->deadline;
725 dl_rq->earliest_dl.next = next_deadline(rq);
726 cpudl_set(&rq->rd->cpudl, rq->cpu, entry->deadline, 1);
732 static inline void inc_dl_deadline(struct dl_rq *dl_rq, u64 deadline) {}
733 static inline void dec_dl_deadline(struct dl_rq *dl_rq, u64 deadline) {}
735 #endif /* CONFIG_SMP */
738 void inc_dl_tasks(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq)
740 int prio = dl_task_of(dl_se)->prio;
741 u64 deadline = dl_se->deadline;
743 WARN_ON(!dl_prio(prio));
744 dl_rq->dl_nr_running++;
745 add_nr_running(rq_of_dl_rq(dl_rq), 1);
747 inc_dl_deadline(dl_rq, deadline);
748 inc_dl_migration(dl_se, dl_rq);
752 void dec_dl_tasks(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq)
754 int prio = dl_task_of(dl_se)->prio;
756 WARN_ON(!dl_prio(prio));
757 WARN_ON(!dl_rq->dl_nr_running);
758 dl_rq->dl_nr_running--;
759 sub_nr_running(rq_of_dl_rq(dl_rq), 1);
761 dec_dl_deadline(dl_rq, dl_se->deadline);
762 dec_dl_migration(dl_se, dl_rq);
765 static void __enqueue_dl_entity(struct sched_dl_entity *dl_se)
767 struct dl_rq *dl_rq = dl_rq_of_se(dl_se);
768 struct rb_node **link = &dl_rq->rb_root.rb_node;
769 struct rb_node *parent = NULL;
770 struct sched_dl_entity *entry;
773 BUG_ON(!RB_EMPTY_NODE(&dl_se->rb_node));
777 entry = rb_entry(parent, struct sched_dl_entity, rb_node);
778 if (dl_time_before(dl_se->deadline, entry->deadline))
779 link = &parent->rb_left;
781 link = &parent->rb_right;
787 dl_rq->rb_leftmost = &dl_se->rb_node;
789 rb_link_node(&dl_se->rb_node, parent, link);
790 rb_insert_color(&dl_se->rb_node, &dl_rq->rb_root);
792 inc_dl_tasks(dl_se, dl_rq);
795 static void __dequeue_dl_entity(struct sched_dl_entity *dl_se)
797 struct dl_rq *dl_rq = dl_rq_of_se(dl_se);
799 if (RB_EMPTY_NODE(&dl_se->rb_node))
802 if (dl_rq->rb_leftmost == &dl_se->rb_node) {
803 struct rb_node *next_node;
805 next_node = rb_next(&dl_se->rb_node);
806 dl_rq->rb_leftmost = next_node;
809 rb_erase(&dl_se->rb_node, &dl_rq->rb_root);
810 RB_CLEAR_NODE(&dl_se->rb_node);
812 dec_dl_tasks(dl_se, dl_rq);
816 enqueue_dl_entity(struct sched_dl_entity *dl_se,
817 struct sched_dl_entity *pi_se, int flags)
819 BUG_ON(on_dl_rq(dl_se));
822 * If this is a wakeup or a new instance, the scheduling
823 * parameters of the task might need updating. Otherwise,
824 * we want a replenishment of its runtime.
826 if (dl_se->dl_new || flags & ENQUEUE_WAKEUP)
827 update_dl_entity(dl_se, pi_se);
828 else if (flags & ENQUEUE_REPLENISH)
829 replenish_dl_entity(dl_se, pi_se);
831 __enqueue_dl_entity(dl_se);
834 static void dequeue_dl_entity(struct sched_dl_entity *dl_se)
836 __dequeue_dl_entity(dl_se);
839 static void enqueue_task_dl(struct rq *rq, struct task_struct *p, int flags)
841 struct task_struct *pi_task = rt_mutex_get_top_task(p);
842 struct sched_dl_entity *pi_se = &p->dl;
845 * Use the scheduling parameters of the top pi-waiter
846 * task if we have one and its (relative) deadline is
847 * smaller than our one... OTW we keep our runtime and
850 if (pi_task && p->dl.dl_boosted && dl_prio(pi_task->normal_prio)) {
851 pi_se = &pi_task->dl;
852 } else if (!dl_prio(p->normal_prio)) {
854 * Special case in which we have a !SCHED_DEADLINE task
855 * that is going to be deboosted, but exceedes its
856 * runtime while doing so. No point in replenishing
857 * it, as it's going to return back to its original
858 * scheduling class after this.
860 BUG_ON(!p->dl.dl_boosted || flags != ENQUEUE_REPLENISH);
865 * If p is throttled, we do nothing. In fact, if it exhausted
866 * its budget it needs a replenishment and, since it now is on
867 * its rq, the bandwidth timer callback (which clearly has not
868 * run yet) will take care of this.
870 if (p->dl.dl_throttled && !(flags & ENQUEUE_REPLENISH))
873 enqueue_dl_entity(&p->dl, pi_se, flags);
875 if (!task_current(rq, p) && p->nr_cpus_allowed > 1)
876 enqueue_pushable_dl_task(rq, p);
879 static void __dequeue_task_dl(struct rq *rq, struct task_struct *p, int flags)
881 dequeue_dl_entity(&p->dl);
882 dequeue_pushable_dl_task(rq, p);
885 static void dequeue_task_dl(struct rq *rq, struct task_struct *p, int flags)
888 __dequeue_task_dl(rq, p, flags);
892 * Yield task semantic for -deadline tasks is:
894 * get off from the CPU until our next instance, with
895 * a new runtime. This is of little use now, since we
896 * don't have a bandwidth reclaiming mechanism. Anyway,
897 * bandwidth reclaiming is planned for the future, and
898 * yield_task_dl will indicate that some spare budget
899 * is available for other task instances to use it.
901 static void yield_task_dl(struct rq *rq)
903 struct task_struct *p = rq->curr;
906 * We make the task go to sleep until its current deadline by
907 * forcing its runtime to zero. This way, update_curr_dl() stops
908 * it and the bandwidth timer will wake it up and will give it
909 * new scheduling parameters (thanks to dl_yielded=1).
911 if (p->dl.runtime > 0) {
912 rq->curr->dl.dl_yielded = 1;
918 * Tell update_rq_clock() that we've just updated,
919 * so we don't do microscopic update in schedule()
920 * and double the fastpath cost.
922 rq_clock_skip_update(rq, true);
927 static int find_later_rq(struct task_struct *task);
930 select_task_rq_dl(struct task_struct *p, int cpu, int sd_flag, int flags)
932 struct task_struct *curr;
935 if (sd_flag != SD_BALANCE_WAKE)
941 curr = ACCESS_ONCE(rq->curr); /* unlocked access */
944 * If we are dealing with a -deadline task, we must
945 * decide where to wake it up.
946 * If it has a later deadline and the current task
947 * on this rq can't move (provided the waking task
948 * can!) we prefer to send it somewhere else. On the
949 * other hand, if it has a shorter deadline, we
950 * try to make it stay here, it might be important.
952 if (unlikely(dl_task(curr)) &&
953 (curr->nr_cpus_allowed < 2 ||
954 !dl_entity_preempt(&p->dl, &curr->dl)) &&
955 (p->nr_cpus_allowed > 1)) {
956 int target = find_later_rq(p);
967 static void check_preempt_equal_dl(struct rq *rq, struct task_struct *p)
970 * Current can't be migrated, useless to reschedule,
971 * let's hope p can move out.
973 if (rq->curr->nr_cpus_allowed == 1 ||
974 cpudl_find(&rq->rd->cpudl, rq->curr, NULL) == -1)
978 * p is migratable, so let's not schedule it and
979 * see if it is pushed or pulled somewhere else.
981 if (p->nr_cpus_allowed != 1 &&
982 cpudl_find(&rq->rd->cpudl, p, NULL) != -1)
988 static int pull_dl_task(struct rq *this_rq);
990 #endif /* CONFIG_SMP */
993 * Only called when both the current and waking task are -deadline
996 static void check_preempt_curr_dl(struct rq *rq, struct task_struct *p,
999 if (dl_entity_preempt(&p->dl, &rq->curr->dl)) {
1006 * In the unlikely case current and p have the same deadline
1007 * let us try to decide what's the best thing to do...
1009 if ((p->dl.deadline == rq->curr->dl.deadline) &&
1010 !test_tsk_need_resched(rq->curr))
1011 check_preempt_equal_dl(rq, p);
1012 #endif /* CONFIG_SMP */
1015 #ifdef CONFIG_SCHED_HRTICK
1016 static void start_hrtick_dl(struct rq *rq, struct task_struct *p)
1018 hrtick_start(rq, p->dl.runtime);
1020 #else /* !CONFIG_SCHED_HRTICK */
1021 static void start_hrtick_dl(struct rq *rq, struct task_struct *p)
1026 static struct sched_dl_entity *pick_next_dl_entity(struct rq *rq,
1027 struct dl_rq *dl_rq)
1029 struct rb_node *left = dl_rq->rb_leftmost;
1034 return rb_entry(left, struct sched_dl_entity, rb_node);
1037 struct task_struct *pick_next_task_dl(struct rq *rq, struct task_struct *prev)
1039 struct sched_dl_entity *dl_se;
1040 struct task_struct *p;
1041 struct dl_rq *dl_rq;
1045 if (need_pull_dl_task(rq, prev)) {
1048 * pull_rt_task() can drop (and re-acquire) rq->lock; this
1049 * means a stop task can slip in, in which case we need to
1050 * re-start task selection.
1052 if (rq->stop && task_on_rq_queued(rq->stop))
1057 * When prev is DL, we may throttle it in put_prev_task().
1058 * So, we update time before we check for dl_nr_running.
1060 if (prev->sched_class == &dl_sched_class)
1063 if (unlikely(!dl_rq->dl_nr_running))
1066 put_prev_task(rq, prev);
1068 dl_se = pick_next_dl_entity(rq, dl_rq);
1071 p = dl_task_of(dl_se);
1072 p->se.exec_start = rq_clock_task(rq);
1074 /* Running task will never be pushed. */
1075 dequeue_pushable_dl_task(rq, p);
1077 if (hrtick_enabled(rq))
1078 start_hrtick_dl(rq, p);
1080 set_post_schedule(rq);
1085 static void put_prev_task_dl(struct rq *rq, struct task_struct *p)
1089 if (on_dl_rq(&p->dl) && p->nr_cpus_allowed > 1)
1090 enqueue_pushable_dl_task(rq, p);
1093 static void task_tick_dl(struct rq *rq, struct task_struct *p, int queued)
1098 * Even when we have runtime, update_curr_dl() might have resulted in us
1099 * not being the leftmost task anymore. In that case NEED_RESCHED will
1100 * be set and schedule() will start a new hrtick for the next task.
1102 if (hrtick_enabled(rq) && queued && p->dl.runtime > 0 &&
1103 is_leftmost(p, &rq->dl))
1104 start_hrtick_dl(rq, p);
1107 static void task_fork_dl(struct task_struct *p)
1110 * SCHED_DEADLINE tasks cannot fork and this is achieved through
1115 static void task_dead_dl(struct task_struct *p)
1117 struct hrtimer *timer = &p->dl.dl_timer;
1118 struct dl_bw *dl_b = dl_bw_of(task_cpu(p));
1121 * Since we are TASK_DEAD we won't slip out of the domain!
1123 raw_spin_lock_irq(&dl_b->lock);
1124 /* XXX we should retain the bw until 0-lag */
1125 dl_b->total_bw -= p->dl.dl_bw;
1126 raw_spin_unlock_irq(&dl_b->lock);
1128 hrtimer_cancel(timer);
1131 static void set_curr_task_dl(struct rq *rq)
1133 struct task_struct *p = rq->curr;
1135 p->se.exec_start = rq_clock_task(rq);
1137 /* You can't push away the running task */
1138 dequeue_pushable_dl_task(rq, p);
1143 /* Only try algorithms three times */
1144 #define DL_MAX_TRIES 3
1146 static int pick_dl_task(struct rq *rq, struct task_struct *p, int cpu)
1148 if (!task_running(rq, p) &&
1149 cpumask_test_cpu(cpu, tsk_cpus_allowed(p)))
1154 /* Returns the second earliest -deadline task, NULL otherwise */
1155 static struct task_struct *pick_next_earliest_dl_task(struct rq *rq, int cpu)
1157 struct rb_node *next_node = rq->dl.rb_leftmost;
1158 struct sched_dl_entity *dl_se;
1159 struct task_struct *p = NULL;
1162 next_node = rb_next(next_node);
1164 dl_se = rb_entry(next_node, struct sched_dl_entity, rb_node);
1165 p = dl_task_of(dl_se);
1167 if (pick_dl_task(rq, p, cpu))
1176 static DEFINE_PER_CPU(cpumask_var_t, local_cpu_mask_dl);
1178 static int find_later_rq(struct task_struct *task)
1180 struct sched_domain *sd;
1181 struct cpumask *later_mask = this_cpu_cpumask_var_ptr(local_cpu_mask_dl);
1182 int this_cpu = smp_processor_id();
1183 int best_cpu, cpu = task_cpu(task);
1185 /* Make sure the mask is initialized first */
1186 if (unlikely(!later_mask))
1189 if (task->nr_cpus_allowed == 1)
1193 * We have to consider system topology and task affinity
1194 * first, then we can look for a suitable cpu.
1196 best_cpu = cpudl_find(&task_rq(task)->rd->cpudl,
1202 * If we are here, some target has been found,
1203 * the most suitable of which is cached in best_cpu.
1204 * This is, among the runqueues where the current tasks
1205 * have later deadlines than the task's one, the rq
1206 * with the latest possible one.
1208 * Now we check how well this matches with task's
1209 * affinity and system topology.
1211 * The last cpu where the task run is our first
1212 * guess, since it is most likely cache-hot there.
1214 if (cpumask_test_cpu(cpu, later_mask))
1217 * Check if this_cpu is to be skipped (i.e., it is
1218 * not in the mask) or not.
1220 if (!cpumask_test_cpu(this_cpu, later_mask))
1224 for_each_domain(cpu, sd) {
1225 if (sd->flags & SD_WAKE_AFFINE) {
1228 * If possible, preempting this_cpu is
1229 * cheaper than migrating.
1231 if (this_cpu != -1 &&
1232 cpumask_test_cpu(this_cpu, sched_domain_span(sd))) {
1238 * Last chance: if best_cpu is valid and is
1239 * in the mask, that becomes our choice.
1241 if (best_cpu < nr_cpu_ids &&
1242 cpumask_test_cpu(best_cpu, sched_domain_span(sd))) {
1251 * At this point, all our guesses failed, we just return
1252 * 'something', and let the caller sort the things out.
1257 cpu = cpumask_any(later_mask);
1258 if (cpu < nr_cpu_ids)
1264 /* Locks the rq it finds */
1265 static struct rq *find_lock_later_rq(struct task_struct *task, struct rq *rq)
1267 struct rq *later_rq = NULL;
1271 for (tries = 0; tries < DL_MAX_TRIES; tries++) {
1272 cpu = find_later_rq(task);
1274 if ((cpu == -1) || (cpu == rq->cpu))
1277 later_rq = cpu_rq(cpu);
1279 /* Retry if something changed. */
1280 if (double_lock_balance(rq, later_rq)) {
1281 if (unlikely(task_rq(task) != rq ||
1282 !cpumask_test_cpu(later_rq->cpu,
1283 &task->cpus_allowed) ||
1284 task_running(rq, task) ||
1285 !task_on_rq_queued(task))) {
1286 double_unlock_balance(rq, later_rq);
1293 * If the rq we found has no -deadline task, or
1294 * its earliest one has a later deadline than our
1295 * task, the rq is a good one.
1297 if (!later_rq->dl.dl_nr_running ||
1298 dl_time_before(task->dl.deadline,
1299 later_rq->dl.earliest_dl.curr))
1302 /* Otherwise we try again. */
1303 double_unlock_balance(rq, later_rq);
1310 static struct task_struct *pick_next_pushable_dl_task(struct rq *rq)
1312 struct task_struct *p;
1314 if (!has_pushable_dl_tasks(rq))
1317 p = rb_entry(rq->dl.pushable_dl_tasks_leftmost,
1318 struct task_struct, pushable_dl_tasks);
1320 BUG_ON(rq->cpu != task_cpu(p));
1321 BUG_ON(task_current(rq, p));
1322 BUG_ON(p->nr_cpus_allowed <= 1);
1324 BUG_ON(!task_on_rq_queued(p));
1325 BUG_ON(!dl_task(p));
1331 * See if the non running -deadline tasks on this rq
1332 * can be sent to some other CPU where they can preempt
1333 * and start executing.
1335 static int push_dl_task(struct rq *rq)
1337 struct task_struct *next_task;
1338 struct rq *later_rq;
1341 if (!rq->dl.overloaded)
1344 next_task = pick_next_pushable_dl_task(rq);
1349 if (unlikely(next_task == rq->curr)) {
1355 * If next_task preempts rq->curr, and rq->curr
1356 * can move away, it makes sense to just reschedule
1357 * without going further in pushing next_task.
1359 if (dl_task(rq->curr) &&
1360 dl_time_before(next_task->dl.deadline, rq->curr->dl.deadline) &&
1361 rq->curr->nr_cpus_allowed > 1) {
1366 /* We might release rq lock */
1367 get_task_struct(next_task);
1369 /* Will lock the rq it'll find */
1370 later_rq = find_lock_later_rq(next_task, rq);
1372 struct task_struct *task;
1375 * We must check all this again, since
1376 * find_lock_later_rq releases rq->lock and it is
1377 * then possible that next_task has migrated.
1379 task = pick_next_pushable_dl_task(rq);
1380 if (task_cpu(next_task) == rq->cpu && task == next_task) {
1382 * The task is still there. We don't try
1383 * again, some other cpu will pull it when ready.
1392 put_task_struct(next_task);
1397 deactivate_task(rq, next_task, 0);
1398 set_task_cpu(next_task, later_rq->cpu);
1399 activate_task(later_rq, next_task, 0);
1402 resched_curr(later_rq);
1404 double_unlock_balance(rq, later_rq);
1407 put_task_struct(next_task);
1412 static void push_dl_tasks(struct rq *rq)
1414 /* Terminates as it moves a -deadline task */
1415 while (push_dl_task(rq))
1419 static int pull_dl_task(struct rq *this_rq)
1421 int this_cpu = this_rq->cpu, ret = 0, cpu;
1422 struct task_struct *p;
1424 u64 dmin = LONG_MAX;
1426 if (likely(!dl_overloaded(this_rq)))
1430 * Match the barrier from dl_set_overloaded; this guarantees that if we
1431 * see overloaded we must also see the dlo_mask bit.
1435 for_each_cpu(cpu, this_rq->rd->dlo_mask) {
1436 if (this_cpu == cpu)
1439 src_rq = cpu_rq(cpu);
1442 * It looks racy, abd it is! However, as in sched_rt.c,
1443 * we are fine with this.
1445 if (this_rq->dl.dl_nr_running &&
1446 dl_time_before(this_rq->dl.earliest_dl.curr,
1447 src_rq->dl.earliest_dl.next))
1450 /* Might drop this_rq->lock */
1451 double_lock_balance(this_rq, src_rq);
1454 * If there are no more pullable tasks on the
1455 * rq, we're done with it.
1457 if (src_rq->dl.dl_nr_running <= 1)
1460 p = pick_next_earliest_dl_task(src_rq, this_cpu);
1463 * We found a task to be pulled if:
1464 * - it preempts our current (if there's one),
1465 * - it will preempt the last one we pulled (if any).
1467 if (p && dl_time_before(p->dl.deadline, dmin) &&
1468 (!this_rq->dl.dl_nr_running ||
1469 dl_time_before(p->dl.deadline,
1470 this_rq->dl.earliest_dl.curr))) {
1471 WARN_ON(p == src_rq->curr);
1472 WARN_ON(!task_on_rq_queued(p));
1475 * Then we pull iff p has actually an earlier
1476 * deadline than the current task of its runqueue.
1478 if (dl_time_before(p->dl.deadline,
1479 src_rq->curr->dl.deadline))
1484 deactivate_task(src_rq, p, 0);
1485 set_task_cpu(p, this_cpu);
1486 activate_task(this_rq, p, 0);
1487 dmin = p->dl.deadline;
1489 /* Is there any other task even earlier? */
1492 double_unlock_balance(this_rq, src_rq);
1498 static void post_schedule_dl(struct rq *rq)
1504 * Since the task is not running and a reschedule is not going to happen
1505 * anytime soon on its runqueue, we try pushing it away now.
1507 static void task_woken_dl(struct rq *rq, struct task_struct *p)
1509 if (!task_running(rq, p) &&
1510 !test_tsk_need_resched(rq->curr) &&
1511 has_pushable_dl_tasks(rq) &&
1512 p->nr_cpus_allowed > 1 &&
1513 dl_task(rq->curr) &&
1514 (rq->curr->nr_cpus_allowed < 2 ||
1515 !dl_entity_preempt(&p->dl, &rq->curr->dl))) {
1520 static void set_cpus_allowed_dl(struct task_struct *p,
1521 const struct cpumask *new_mask)
1524 struct root_domain *src_rd;
1527 BUG_ON(!dl_task(p));
1532 * Migrating a SCHED_DEADLINE task between exclusive
1533 * cpusets (different root_domains) entails a bandwidth
1534 * update. We already made space for us in the destination
1535 * domain (see cpuset_can_attach()).
1537 if (!cpumask_intersects(src_rd->span, new_mask)) {
1538 struct dl_bw *src_dl_b;
1540 src_dl_b = dl_bw_of(cpu_of(rq));
1542 * We now free resources of the root_domain we are migrating
1543 * off. In the worst case, sched_setattr() may temporary fail
1544 * until we complete the update.
1546 raw_spin_lock(&src_dl_b->lock);
1547 __dl_clear(src_dl_b, p->dl.dl_bw);
1548 raw_spin_unlock(&src_dl_b->lock);
1552 * Update only if the task is actually running (i.e.,
1553 * it is on the rq AND it is not throttled).
1555 if (!on_dl_rq(&p->dl))
1558 weight = cpumask_weight(new_mask);
1561 * Only update if the process changes its state from whether it
1562 * can migrate or not.
1564 if ((p->nr_cpus_allowed > 1) == (weight > 1))
1568 * The process used to be able to migrate OR it can now migrate
1571 if (!task_current(rq, p))
1572 dequeue_pushable_dl_task(rq, p);
1573 BUG_ON(!rq->dl.dl_nr_migratory);
1574 rq->dl.dl_nr_migratory--;
1576 if (!task_current(rq, p))
1577 enqueue_pushable_dl_task(rq, p);
1578 rq->dl.dl_nr_migratory++;
1581 update_dl_migration(&rq->dl);
1584 /* Assumes rq->lock is held */
1585 static void rq_online_dl(struct rq *rq)
1587 if (rq->dl.overloaded)
1588 dl_set_overload(rq);
1590 cpudl_set_freecpu(&rq->rd->cpudl, rq->cpu);
1591 if (rq->dl.dl_nr_running > 0)
1592 cpudl_set(&rq->rd->cpudl, rq->cpu, rq->dl.earliest_dl.curr, 1);
1595 /* Assumes rq->lock is held */
1596 static void rq_offline_dl(struct rq *rq)
1598 if (rq->dl.overloaded)
1599 dl_clear_overload(rq);
1601 cpudl_set(&rq->rd->cpudl, rq->cpu, 0, 0);
1602 cpudl_clear_freecpu(&rq->rd->cpudl, rq->cpu);
1605 void init_sched_dl_class(void)
1609 for_each_possible_cpu(i)
1610 zalloc_cpumask_var_node(&per_cpu(local_cpu_mask_dl, i),
1611 GFP_KERNEL, cpu_to_node(i));
1614 #endif /* CONFIG_SMP */
1617 * Ensure p's dl_timer is cancelled. May drop rq->lock for a while.
1619 static void cancel_dl_timer(struct rq *rq, struct task_struct *p)
1621 struct hrtimer *dl_timer = &p->dl.dl_timer;
1623 /* Nobody will change task's class if pi_lock is held */
1624 lockdep_assert_held(&p->pi_lock);
1626 if (hrtimer_active(dl_timer)) {
1627 int ret = hrtimer_try_to_cancel(dl_timer);
1629 if (unlikely(ret == -1)) {
1631 * Note, p may migrate OR new deadline tasks
1632 * may appear in rq when we are unlocking it.
1633 * A caller of us must be fine with that.
1635 raw_spin_unlock(&rq->lock);
1636 hrtimer_cancel(dl_timer);
1637 raw_spin_lock(&rq->lock);
1642 static void switched_from_dl(struct rq *rq, struct task_struct *p)
1644 /* XXX we should retain the bw until 0-lag */
1645 cancel_dl_timer(rq, p);
1646 __dl_clear_params(p);
1649 * Since this might be the only -deadline task on the rq,
1650 * this is the right place to try to pull some other one
1651 * from an overloaded cpu, if any.
1653 if (!task_on_rq_queued(p) || rq->dl.dl_nr_running)
1656 if (pull_dl_task(rq))
1661 * When switching to -deadline, we may overload the rq, then
1662 * we try to push someone off, if possible.
1664 static void switched_to_dl(struct rq *rq, struct task_struct *p)
1666 int check_resched = 1;
1668 if (task_on_rq_queued(p) && rq->curr != p) {
1670 if (p->nr_cpus_allowed > 1 && rq->dl.overloaded &&
1671 push_dl_task(rq) && rq != task_rq(p))
1672 /* Only reschedule if pushing failed */
1674 #endif /* CONFIG_SMP */
1675 if (check_resched) {
1676 if (dl_task(rq->curr))
1677 check_preempt_curr_dl(rq, p, 0);
1685 * If the scheduling parameters of a -deadline task changed,
1686 * a push or pull operation might be needed.
1688 static void prio_changed_dl(struct rq *rq, struct task_struct *p,
1691 if (task_on_rq_queued(p) || rq->curr == p) {
1694 * This might be too much, but unfortunately
1695 * we don't have the old deadline value, and
1696 * we can't argue if the task is increasing
1697 * or lowering its prio, so...
1699 if (!rq->dl.overloaded)
1703 * If we now have a earlier deadline task than p,
1704 * then reschedule, provided p is still on this
1707 if (dl_time_before(rq->dl.earliest_dl.curr, p->dl.deadline) &&
1712 * Again, we don't know if p has a earlier
1713 * or later deadline, so let's blindly set a
1714 * (maybe not needed) rescheduling point.
1717 #endif /* CONFIG_SMP */
1719 switched_to_dl(rq, p);
1722 const struct sched_class dl_sched_class = {
1723 .next = &rt_sched_class,
1724 .enqueue_task = enqueue_task_dl,
1725 .dequeue_task = dequeue_task_dl,
1726 .yield_task = yield_task_dl,
1728 .check_preempt_curr = check_preempt_curr_dl,
1730 .pick_next_task = pick_next_task_dl,
1731 .put_prev_task = put_prev_task_dl,
1734 .select_task_rq = select_task_rq_dl,
1735 .set_cpus_allowed = set_cpus_allowed_dl,
1736 .rq_online = rq_online_dl,
1737 .rq_offline = rq_offline_dl,
1738 .post_schedule = post_schedule_dl,
1739 .task_woken = task_woken_dl,
1742 .set_curr_task = set_curr_task_dl,
1743 .task_tick = task_tick_dl,
1744 .task_fork = task_fork_dl,
1745 .task_dead = task_dead_dl,
1747 .prio_changed = prio_changed_dl,
1748 .switched_from = switched_from_dl,
1749 .switched_to = switched_to_dl,
1751 .update_curr = update_curr_dl,
1754 #ifdef CONFIG_SCHED_DEBUG
1755 extern void print_dl_rq(struct seq_file *m, int cpu, struct dl_rq *dl_rq);
1757 void print_dl_stats(struct seq_file *m, int cpu)
1759 print_dl_rq(m, cpu, &cpu_rq(cpu)->dl);
1761 #endif /* CONFIG_SCHED_DEBUG */