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 (tsk_nr_cpus_allowed(p) > 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 (tsk_nr_cpus_allowed(p) > 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;
181 dl_rq->earliest_dl.next = p->dl.deadline;
184 rb_link_node(&p->pushable_dl_tasks, parent, link);
185 rb_insert_color(&p->pushable_dl_tasks, &dl_rq->pushable_dl_tasks_root);
188 static void dequeue_pushable_dl_task(struct rq *rq, struct task_struct *p)
190 struct dl_rq *dl_rq = &rq->dl;
192 if (RB_EMPTY_NODE(&p->pushable_dl_tasks))
195 if (dl_rq->pushable_dl_tasks_leftmost == &p->pushable_dl_tasks) {
196 struct rb_node *next_node;
198 next_node = rb_next(&p->pushable_dl_tasks);
199 dl_rq->pushable_dl_tasks_leftmost = next_node;
201 dl_rq->earliest_dl.next = rb_entry(next_node,
202 struct task_struct, pushable_dl_tasks)->dl.deadline;
206 rb_erase(&p->pushable_dl_tasks, &dl_rq->pushable_dl_tasks_root);
207 RB_CLEAR_NODE(&p->pushable_dl_tasks);
210 static inline int has_pushable_dl_tasks(struct rq *rq)
212 return !RB_EMPTY_ROOT(&rq->dl.pushable_dl_tasks_root);
215 static int push_dl_task(struct rq *rq);
217 static inline bool need_pull_dl_task(struct rq *rq, struct task_struct *prev)
219 return dl_task(prev);
222 static DEFINE_PER_CPU(struct callback_head, dl_push_head);
223 static DEFINE_PER_CPU(struct callback_head, dl_pull_head);
225 static void push_dl_tasks(struct rq *);
226 static void pull_dl_task(struct rq *);
228 static inline void queue_push_tasks(struct rq *rq)
230 if (!has_pushable_dl_tasks(rq))
233 queue_balance_callback(rq, &per_cpu(dl_push_head, rq->cpu), push_dl_tasks);
236 static inline void queue_pull_task(struct rq *rq)
238 queue_balance_callback(rq, &per_cpu(dl_pull_head, rq->cpu), pull_dl_task);
241 static struct rq *find_lock_later_rq(struct task_struct *task, struct rq *rq);
243 static struct rq *dl_task_offline_migration(struct rq *rq, struct task_struct *p)
245 struct rq *later_rq = NULL;
247 later_rq = find_lock_later_rq(p, rq);
252 * If we cannot preempt any rq, fall back to pick any
255 cpu = cpumask_any_and(cpu_active_mask, tsk_cpus_allowed(p));
256 if (cpu >= nr_cpu_ids) {
258 * Fail to find any suitable cpu.
259 * The task will never come back!
261 BUG_ON(dl_bandwidth_enabled());
264 * If admission control is disabled we
265 * try a little harder to let the task
268 cpu = cpumask_any(cpu_active_mask);
270 later_rq = cpu_rq(cpu);
271 double_lock_balance(rq, later_rq);
274 set_task_cpu(p, later_rq->cpu);
275 double_unlock_balance(later_rq, rq);
283 void enqueue_pushable_dl_task(struct rq *rq, struct task_struct *p)
288 void dequeue_pushable_dl_task(struct rq *rq, struct task_struct *p)
293 void inc_dl_migration(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq)
298 void dec_dl_migration(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq)
302 static inline bool need_pull_dl_task(struct rq *rq, struct task_struct *prev)
307 static inline void pull_dl_task(struct rq *rq)
311 static inline void queue_push_tasks(struct rq *rq)
315 static inline void queue_pull_task(struct rq *rq)
318 #endif /* CONFIG_SMP */
320 static void enqueue_task_dl(struct rq *rq, struct task_struct *p, int flags);
321 static void __dequeue_task_dl(struct rq *rq, struct task_struct *p, int flags);
322 static void check_preempt_curr_dl(struct rq *rq, struct task_struct *p,
326 * We are being explicitly informed that a new instance is starting,
327 * and this means that:
328 * - the absolute deadline of the entity has to be placed at
329 * current time + relative deadline;
330 * - the runtime of the entity has to be set to the maximum value.
332 * The capability of specifying such event is useful whenever a -deadline
333 * entity wants to (try to!) synchronize its behaviour with the scheduler's
334 * one, and to (try to!) reconcile itself with its own scheduling
337 static inline void setup_new_dl_entity(struct sched_dl_entity *dl_se)
339 struct dl_rq *dl_rq = dl_rq_of_se(dl_se);
340 struct rq *rq = rq_of_dl_rq(dl_rq);
342 WARN_ON(dl_se->dl_boosted);
343 WARN_ON(dl_time_before(rq_clock(rq), dl_se->deadline));
346 * We are racing with the deadline timer. So, do nothing because
347 * the deadline timer handler will take care of properly recharging
348 * the runtime and postponing the deadline
350 if (dl_se->dl_throttled)
354 * We use the regular wall clock time to set deadlines in the
355 * future; in fact, we must consider execution overheads (time
356 * spent on hardirq context, etc.).
358 dl_se->deadline = rq_clock(rq) + dl_se->dl_deadline;
359 dl_se->runtime = dl_se->dl_runtime;
363 * Pure Earliest Deadline First (EDF) scheduling does not deal with the
364 * possibility of a entity lasting more than what it declared, and thus
365 * exhausting its runtime.
367 * Here we are interested in making runtime overrun possible, but we do
368 * not want a entity which is misbehaving to affect the scheduling of all
370 * Therefore, a budgeting strategy called Constant Bandwidth Server (CBS)
371 * is used, in order to confine each entity within its own bandwidth.
373 * This function deals exactly with that, and ensures that when the runtime
374 * of a entity is replenished, its deadline is also postponed. That ensures
375 * the overrunning entity can't interfere with other entity in the system and
376 * can't make them miss their deadlines. Reasons why this kind of overruns
377 * could happen are, typically, a entity voluntarily trying to overcome its
378 * runtime, or it just underestimated it during sched_setattr().
380 static void replenish_dl_entity(struct sched_dl_entity *dl_se,
381 struct sched_dl_entity *pi_se)
383 struct dl_rq *dl_rq = dl_rq_of_se(dl_se);
384 struct rq *rq = rq_of_dl_rq(dl_rq);
386 BUG_ON(pi_se->dl_runtime <= 0);
389 * This could be the case for a !-dl task that is boosted.
390 * Just go with full inherited parameters.
392 if (dl_se->dl_deadline == 0) {
393 dl_se->deadline = rq_clock(rq) + pi_se->dl_deadline;
394 dl_se->runtime = pi_se->dl_runtime;
397 if (dl_se->dl_yielded && dl_se->runtime > 0)
401 * We keep moving the deadline away until we get some
402 * available runtime for the entity. This ensures correct
403 * handling of situations where the runtime overrun is
406 while (dl_se->runtime <= 0) {
407 dl_se->deadline += pi_se->dl_period;
408 dl_se->runtime += pi_se->dl_runtime;
412 * At this point, the deadline really should be "in
413 * the future" with respect to rq->clock. If it's
414 * not, we are, for some reason, lagging too much!
415 * Anyway, after having warn userspace abut that,
416 * we still try to keep the things running by
417 * resetting the deadline and the budget of the
420 if (dl_time_before(dl_se->deadline, rq_clock(rq))) {
421 printk_deferred_once("sched: DL replenish lagged too much\n");
422 dl_se->deadline = rq_clock(rq) + pi_se->dl_deadline;
423 dl_se->runtime = pi_se->dl_runtime;
426 if (dl_se->dl_yielded)
427 dl_se->dl_yielded = 0;
428 if (dl_se->dl_throttled)
429 dl_se->dl_throttled = 0;
433 * Here we check if --at time t-- an entity (which is probably being
434 * [re]activated or, in general, enqueued) can use its remaining runtime
435 * and its current deadline _without_ exceeding the bandwidth it is
436 * assigned (function returns true if it can't). We are in fact applying
437 * one of the CBS rules: when a task wakes up, if the residual runtime
438 * over residual deadline fits within the allocated bandwidth, then we
439 * can keep the current (absolute) deadline and residual budget without
440 * disrupting the schedulability of the system. Otherwise, we should
441 * refill the runtime and set the deadline a period in the future,
442 * because keeping the current (absolute) deadline of the task would
443 * result in breaking guarantees promised to other tasks (refer to
444 * Documentation/scheduler/sched-deadline.txt for more informations).
446 * This function returns true if:
448 * runtime / (deadline - t) > dl_runtime / dl_period ,
450 * IOW we can't recycle current parameters.
452 * Notice that the bandwidth check is done against the period. For
453 * task with deadline equal to period this is the same of using
454 * dl_deadline instead of dl_period in the equation above.
456 static bool dl_entity_overflow(struct sched_dl_entity *dl_se,
457 struct sched_dl_entity *pi_se, u64 t)
462 * left and right are the two sides of the equation above,
463 * after a bit of shuffling to use multiplications instead
466 * Note that none of the time values involved in the two
467 * multiplications are absolute: dl_deadline and dl_runtime
468 * are the relative deadline and the maximum runtime of each
469 * instance, runtime is the runtime left for the last instance
470 * and (deadline - t), since t is rq->clock, is the time left
471 * to the (absolute) deadline. Even if overflowing the u64 type
472 * is very unlikely to occur in both cases, here we scale down
473 * as we want to avoid that risk at all. Scaling down by 10
474 * means that we reduce granularity to 1us. We are fine with it,
475 * since this is only a true/false check and, anyway, thinking
476 * of anything below microseconds resolution is actually fiction
477 * (but still we want to give the user that illusion >;).
479 left = (pi_se->dl_period >> DL_SCALE) * (dl_se->runtime >> DL_SCALE);
480 right = ((dl_se->deadline - t) >> DL_SCALE) *
481 (pi_se->dl_runtime >> DL_SCALE);
483 return dl_time_before(right, left);
487 * When a -deadline entity is queued back on the runqueue, its runtime and
488 * deadline might need updating.
490 * The policy here is that we update the deadline of the entity only if:
491 * - the current deadline is in the past,
492 * - using the remaining runtime with the current deadline would make
493 * the entity exceed its bandwidth.
495 static void update_dl_entity(struct sched_dl_entity *dl_se,
496 struct sched_dl_entity *pi_se)
498 struct dl_rq *dl_rq = dl_rq_of_se(dl_se);
499 struct rq *rq = rq_of_dl_rq(dl_rq);
501 if (dl_time_before(dl_se->deadline, rq_clock(rq)) ||
502 dl_entity_overflow(dl_se, pi_se, rq_clock(rq))) {
503 dl_se->deadline = rq_clock(rq) + pi_se->dl_deadline;
504 dl_se->runtime = pi_se->dl_runtime;
509 * If the entity depleted all its runtime, and if we want it to sleep
510 * while waiting for some new execution time to become available, we
511 * set the bandwidth enforcement timer to the replenishment instant
512 * and try to activate it.
514 * Notice that it is important for the caller to know if the timer
515 * actually started or not (i.e., the replenishment instant is in
516 * the future or in the past).
518 static int start_dl_timer(struct task_struct *p)
520 struct sched_dl_entity *dl_se = &p->dl;
521 struct hrtimer *timer = &dl_se->dl_timer;
522 struct rq *rq = task_rq(p);
526 lockdep_assert_held(&rq->lock);
529 * We want the timer to fire at the deadline, but considering
530 * that it is actually coming from rq->clock and not from
531 * hrtimer's time base reading.
533 act = ns_to_ktime(dl_se->deadline);
534 now = hrtimer_cb_get_time(timer);
535 delta = ktime_to_ns(now) - rq_clock(rq);
536 act = ktime_add_ns(act, delta);
539 * If the expiry time already passed, e.g., because the value
540 * chosen as the deadline is too small, don't even try to
541 * start the timer in the past!
543 if (ktime_us_delta(act, now) < 0)
547 * !enqueued will guarantee another callback; even if one is already in
548 * progress. This ensures a balanced {get,put}_task_struct().
550 * The race against __run_timer() clearing the enqueued state is
551 * harmless because we're holding task_rq()->lock, therefore the timer
552 * expiring after we've done the check will wait on its task_rq_lock()
553 * and observe our state.
555 if (!hrtimer_is_queued(timer)) {
557 hrtimer_start(timer, act, HRTIMER_MODE_ABS);
564 * This is the bandwidth enforcement timer callback. If here, we know
565 * a task is not on its dl_rq, since the fact that the timer was running
566 * means the task is throttled and needs a runtime replenishment.
568 * However, what we actually do depends on the fact the task is active,
569 * (it is on its rq) or has been removed from there by a call to
570 * dequeue_task_dl(). In the former case we must issue the runtime
571 * replenishment and add the task back to the dl_rq; in the latter, we just
572 * do nothing but clearing dl_throttled, so that runtime and deadline
573 * updating (and the queueing back to dl_rq) will be done by the
574 * next call to enqueue_task_dl().
576 static enum hrtimer_restart dl_task_timer(struct hrtimer *timer)
578 struct sched_dl_entity *dl_se = container_of(timer,
579 struct sched_dl_entity,
581 struct task_struct *p = dl_task_of(dl_se);
585 rq = task_rq_lock(p, &rf);
588 * The task might have changed its scheduling policy to something
589 * different than SCHED_DEADLINE (through switched_fromd_dl()).
592 __dl_clear_params(p);
597 * The task might have been boosted by someone else and might be in the
598 * boosting/deboosting path, its not throttled.
600 if (dl_se->dl_boosted)
604 * Spurious timer due to start_dl_timer() race; or we already received
605 * a replenishment from rt_mutex_setprio().
607 if (!dl_se->dl_throttled)
614 * If the throttle happened during sched-out; like:
621 * __dequeue_task_dl()
624 * We can be both throttled and !queued. Replenish the counter
625 * but do not enqueue -- wait for our wakeup to do that.
627 if (!task_on_rq_queued(p)) {
628 replenish_dl_entity(dl_se, dl_se);
633 if (unlikely(!rq->online)) {
635 * If the runqueue is no longer available, migrate the
636 * task elsewhere. This necessarily changes rq.
638 lockdep_unpin_lock(&rq->lock, rf.cookie);
639 rq = dl_task_offline_migration(rq, p);
640 rf.cookie = lockdep_pin_lock(&rq->lock);
643 * Now that the task has been migrated to the new RQ and we
644 * have that locked, proceed as normal and enqueue the task
650 enqueue_task_dl(rq, p, ENQUEUE_REPLENISH);
651 if (dl_task(rq->curr))
652 check_preempt_curr_dl(rq, p, 0);
658 * Queueing this task back might have overloaded rq, check if we need
659 * to kick someone away.
661 if (has_pushable_dl_tasks(rq)) {
663 * Nothing relies on rq->lock after this, so its safe to drop
666 lockdep_unpin_lock(&rq->lock, rf.cookie);
668 lockdep_repin_lock(&rq->lock, rf.cookie);
673 task_rq_unlock(rq, p, &rf);
676 * This can free the task_struct, including this hrtimer, do not touch
677 * anything related to that after this.
681 return HRTIMER_NORESTART;
684 void init_dl_task_timer(struct sched_dl_entity *dl_se)
686 struct hrtimer *timer = &dl_se->dl_timer;
688 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
689 timer->function = dl_task_timer;
693 int dl_runtime_exceeded(struct sched_dl_entity *dl_se)
695 return (dl_se->runtime <= 0);
698 extern bool sched_rt_bandwidth_account(struct rt_rq *rt_rq);
701 * Update the current task's runtime statistics (provided it is still
702 * a -deadline task and has not been removed from the dl_rq).
704 static void update_curr_dl(struct rq *rq)
706 struct task_struct *curr = rq->curr;
707 struct sched_dl_entity *dl_se = &curr->dl;
710 if (!dl_task(curr) || !on_dl_rq(dl_se))
714 * Consumed budget is computed considering the time as
715 * observed by schedulable tasks (excluding time spent
716 * in hardirq context, etc.). Deadlines are instead
717 * computed using hard walltime. This seems to be the more
718 * natural solution, but the full ramifications of this
719 * approach need further study.
721 delta_exec = rq_clock_task(rq) - curr->se.exec_start;
722 if (unlikely((s64)delta_exec <= 0)) {
723 if (unlikely(dl_se->dl_yielded))
728 /* kick cpufreq (see the comment in linux/cpufreq.h). */
729 if (cpu_of(rq) == smp_processor_id())
730 cpufreq_trigger_update(rq_clock(rq));
732 schedstat_set(curr->se.statistics.exec_max,
733 max(curr->se.statistics.exec_max, delta_exec));
735 curr->se.sum_exec_runtime += delta_exec;
736 account_group_exec_runtime(curr, delta_exec);
738 curr->se.exec_start = rq_clock_task(rq);
739 cpuacct_charge(curr, delta_exec);
741 sched_rt_avg_update(rq, delta_exec);
743 dl_se->runtime -= delta_exec;
746 if (dl_runtime_exceeded(dl_se) || dl_se->dl_yielded) {
747 dl_se->dl_throttled = 1;
748 __dequeue_task_dl(rq, curr, 0);
749 if (unlikely(dl_se->dl_boosted || !start_dl_timer(curr)))
750 enqueue_task_dl(rq, curr, ENQUEUE_REPLENISH);
752 if (!is_leftmost(curr, &rq->dl))
757 * Because -- for now -- we share the rt bandwidth, we need to
758 * account our runtime there too, otherwise actual rt tasks
759 * would be able to exceed the shared quota.
761 * Account to the root rt group for now.
763 * The solution we're working towards is having the RT groups scheduled
764 * using deadline servers -- however there's a few nasties to figure
765 * out before that can happen.
767 if (rt_bandwidth_enabled()) {
768 struct rt_rq *rt_rq = &rq->rt;
770 raw_spin_lock(&rt_rq->rt_runtime_lock);
772 * We'll let actual RT tasks worry about the overflow here, we
773 * have our own CBS to keep us inline; only account when RT
774 * bandwidth is relevant.
776 if (sched_rt_bandwidth_account(rt_rq))
777 rt_rq->rt_time += delta_exec;
778 raw_spin_unlock(&rt_rq->rt_runtime_lock);
784 static void inc_dl_deadline(struct dl_rq *dl_rq, u64 deadline)
786 struct rq *rq = rq_of_dl_rq(dl_rq);
788 if (dl_rq->earliest_dl.curr == 0 ||
789 dl_time_before(deadline, dl_rq->earliest_dl.curr)) {
790 dl_rq->earliest_dl.curr = deadline;
791 cpudl_set(&rq->rd->cpudl, rq->cpu, deadline);
795 static void dec_dl_deadline(struct dl_rq *dl_rq, u64 deadline)
797 struct rq *rq = rq_of_dl_rq(dl_rq);
800 * Since we may have removed our earliest (and/or next earliest)
801 * task we must recompute them.
803 if (!dl_rq->dl_nr_running) {
804 dl_rq->earliest_dl.curr = 0;
805 dl_rq->earliest_dl.next = 0;
806 cpudl_clear(&rq->rd->cpudl, rq->cpu);
808 struct rb_node *leftmost = dl_rq->rb_leftmost;
809 struct sched_dl_entity *entry;
811 entry = rb_entry(leftmost, struct sched_dl_entity, rb_node);
812 dl_rq->earliest_dl.curr = entry->deadline;
813 cpudl_set(&rq->rd->cpudl, rq->cpu, entry->deadline);
819 static inline void inc_dl_deadline(struct dl_rq *dl_rq, u64 deadline) {}
820 static inline void dec_dl_deadline(struct dl_rq *dl_rq, u64 deadline) {}
822 #endif /* CONFIG_SMP */
825 void inc_dl_tasks(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq)
827 int prio = dl_task_of(dl_se)->prio;
828 u64 deadline = dl_se->deadline;
830 WARN_ON(!dl_prio(prio));
831 dl_rq->dl_nr_running++;
832 add_nr_running(rq_of_dl_rq(dl_rq), 1);
834 inc_dl_deadline(dl_rq, deadline);
835 inc_dl_migration(dl_se, dl_rq);
839 void dec_dl_tasks(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq)
841 int prio = dl_task_of(dl_se)->prio;
843 WARN_ON(!dl_prio(prio));
844 WARN_ON(!dl_rq->dl_nr_running);
845 dl_rq->dl_nr_running--;
846 sub_nr_running(rq_of_dl_rq(dl_rq), 1);
848 dec_dl_deadline(dl_rq, dl_se->deadline);
849 dec_dl_migration(dl_se, dl_rq);
852 static void __enqueue_dl_entity(struct sched_dl_entity *dl_se)
854 struct dl_rq *dl_rq = dl_rq_of_se(dl_se);
855 struct rb_node **link = &dl_rq->rb_root.rb_node;
856 struct rb_node *parent = NULL;
857 struct sched_dl_entity *entry;
860 BUG_ON(!RB_EMPTY_NODE(&dl_se->rb_node));
864 entry = rb_entry(parent, struct sched_dl_entity, rb_node);
865 if (dl_time_before(dl_se->deadline, entry->deadline))
866 link = &parent->rb_left;
868 link = &parent->rb_right;
874 dl_rq->rb_leftmost = &dl_se->rb_node;
876 rb_link_node(&dl_se->rb_node, parent, link);
877 rb_insert_color(&dl_se->rb_node, &dl_rq->rb_root);
879 inc_dl_tasks(dl_se, dl_rq);
882 static void __dequeue_dl_entity(struct sched_dl_entity *dl_se)
884 struct dl_rq *dl_rq = dl_rq_of_se(dl_se);
886 if (RB_EMPTY_NODE(&dl_se->rb_node))
889 if (dl_rq->rb_leftmost == &dl_se->rb_node) {
890 struct rb_node *next_node;
892 next_node = rb_next(&dl_se->rb_node);
893 dl_rq->rb_leftmost = next_node;
896 rb_erase(&dl_se->rb_node, &dl_rq->rb_root);
897 RB_CLEAR_NODE(&dl_se->rb_node);
899 dec_dl_tasks(dl_se, dl_rq);
903 enqueue_dl_entity(struct sched_dl_entity *dl_se,
904 struct sched_dl_entity *pi_se, int flags)
906 BUG_ON(on_dl_rq(dl_se));
909 * If this is a wakeup or a new instance, the scheduling
910 * parameters of the task might need updating. Otherwise,
911 * we want a replenishment of its runtime.
913 if (flags & ENQUEUE_WAKEUP)
914 update_dl_entity(dl_se, pi_se);
915 else if (flags & ENQUEUE_REPLENISH)
916 replenish_dl_entity(dl_se, pi_se);
918 __enqueue_dl_entity(dl_se);
921 static void dequeue_dl_entity(struct sched_dl_entity *dl_se)
923 __dequeue_dl_entity(dl_se);
926 static void enqueue_task_dl(struct rq *rq, struct task_struct *p, int flags)
928 struct task_struct *pi_task = rt_mutex_get_top_task(p);
929 struct sched_dl_entity *pi_se = &p->dl;
932 * Use the scheduling parameters of the top pi-waiter
933 * task if we have one and its (absolute) deadline is
934 * smaller than our one... OTW we keep our runtime and
937 if (pi_task && p->dl.dl_boosted && dl_prio(pi_task->normal_prio)) {
938 pi_se = &pi_task->dl;
939 } else if (!dl_prio(p->normal_prio)) {
941 * Special case in which we have a !SCHED_DEADLINE task
942 * that is going to be deboosted, but exceedes its
943 * runtime while doing so. No point in replenishing
944 * it, as it's going to return back to its original
945 * scheduling class after this.
947 BUG_ON(!p->dl.dl_boosted || flags != ENQUEUE_REPLENISH);
952 * If p is throttled, we do nothing. In fact, if it exhausted
953 * its budget it needs a replenishment and, since it now is on
954 * its rq, the bandwidth timer callback (which clearly has not
955 * run yet) will take care of this.
957 if (p->dl.dl_throttled && !(flags & ENQUEUE_REPLENISH))
960 enqueue_dl_entity(&p->dl, pi_se, flags);
962 if (!task_current(rq, p) && tsk_nr_cpus_allowed(p) > 1)
963 enqueue_pushable_dl_task(rq, p);
966 static void __dequeue_task_dl(struct rq *rq, struct task_struct *p, int flags)
968 dequeue_dl_entity(&p->dl);
969 dequeue_pushable_dl_task(rq, p);
972 static void dequeue_task_dl(struct rq *rq, struct task_struct *p, int flags)
975 __dequeue_task_dl(rq, p, flags);
979 * Yield task semantic for -deadline tasks is:
981 * get off from the CPU until our next instance, with
982 * a new runtime. This is of little use now, since we
983 * don't have a bandwidth reclaiming mechanism. Anyway,
984 * bandwidth reclaiming is planned for the future, and
985 * yield_task_dl will indicate that some spare budget
986 * is available for other task instances to use it.
988 static void yield_task_dl(struct rq *rq)
991 * We make the task go to sleep until its current deadline by
992 * forcing its runtime to zero. This way, update_curr_dl() stops
993 * it and the bandwidth timer will wake it up and will give it
994 * new scheduling parameters (thanks to dl_yielded=1).
996 rq->curr->dl.dl_yielded = 1;
1001 * Tell update_rq_clock() that we've just updated,
1002 * so we don't do microscopic update in schedule()
1003 * and double the fastpath cost.
1005 rq_clock_skip_update(rq, true);
1010 static int find_later_rq(struct task_struct *task);
1013 select_task_rq_dl(struct task_struct *p, int cpu, int sd_flag, int flags)
1015 struct task_struct *curr;
1018 if (sd_flag != SD_BALANCE_WAKE)
1024 curr = READ_ONCE(rq->curr); /* unlocked access */
1027 * If we are dealing with a -deadline task, we must
1028 * decide where to wake it up.
1029 * If it has a later deadline and the current task
1030 * on this rq can't move (provided the waking task
1031 * can!) we prefer to send it somewhere else. On the
1032 * other hand, if it has a shorter deadline, we
1033 * try to make it stay here, it might be important.
1035 if (unlikely(dl_task(curr)) &&
1036 (tsk_nr_cpus_allowed(curr) < 2 ||
1037 !dl_entity_preempt(&p->dl, &curr->dl)) &&
1038 (tsk_nr_cpus_allowed(p) > 1)) {
1039 int target = find_later_rq(p);
1042 (dl_time_before(p->dl.deadline,
1043 cpu_rq(target)->dl.earliest_dl.curr) ||
1044 (cpu_rq(target)->dl.dl_nr_running == 0)))
1053 static void check_preempt_equal_dl(struct rq *rq, struct task_struct *p)
1056 * Current can't be migrated, useless to reschedule,
1057 * let's hope p can move out.
1059 if (tsk_nr_cpus_allowed(rq->curr) == 1 ||
1060 cpudl_find(&rq->rd->cpudl, rq->curr, NULL) == -1)
1064 * p is migratable, so let's not schedule it and
1065 * see if it is pushed or pulled somewhere else.
1067 if (tsk_nr_cpus_allowed(p) != 1 &&
1068 cpudl_find(&rq->rd->cpudl, p, NULL) != -1)
1074 #endif /* CONFIG_SMP */
1077 * Only called when both the current and waking task are -deadline
1080 static void check_preempt_curr_dl(struct rq *rq, struct task_struct *p,
1083 if (dl_entity_preempt(&p->dl, &rq->curr->dl)) {
1090 * In the unlikely case current and p have the same deadline
1091 * let us try to decide what's the best thing to do...
1093 if ((p->dl.deadline == rq->curr->dl.deadline) &&
1094 !test_tsk_need_resched(rq->curr))
1095 check_preempt_equal_dl(rq, p);
1096 #endif /* CONFIG_SMP */
1099 #ifdef CONFIG_SCHED_HRTICK
1100 static void start_hrtick_dl(struct rq *rq, struct task_struct *p)
1102 hrtick_start(rq, p->dl.runtime);
1104 #else /* !CONFIG_SCHED_HRTICK */
1105 static void start_hrtick_dl(struct rq *rq, struct task_struct *p)
1110 static struct sched_dl_entity *pick_next_dl_entity(struct rq *rq,
1111 struct dl_rq *dl_rq)
1113 struct rb_node *left = dl_rq->rb_leftmost;
1118 return rb_entry(left, struct sched_dl_entity, rb_node);
1121 struct task_struct *
1122 pick_next_task_dl(struct rq *rq, struct task_struct *prev, struct pin_cookie cookie)
1124 struct sched_dl_entity *dl_se;
1125 struct task_struct *p;
1126 struct dl_rq *dl_rq;
1130 if (need_pull_dl_task(rq, prev)) {
1132 * This is OK, because current is on_cpu, which avoids it being
1133 * picked for load-balance and preemption/IRQs are still
1134 * disabled avoiding further scheduler activity on it and we're
1135 * being very careful to re-start the picking loop.
1137 lockdep_unpin_lock(&rq->lock, cookie);
1139 lockdep_repin_lock(&rq->lock, cookie);
1141 * pull_rt_task() can drop (and re-acquire) rq->lock; this
1142 * means a stop task can slip in, in which case we need to
1143 * re-start task selection.
1145 if (rq->stop && task_on_rq_queued(rq->stop))
1150 * When prev is DL, we may throttle it in put_prev_task().
1151 * So, we update time before we check for dl_nr_running.
1153 if (prev->sched_class == &dl_sched_class)
1156 if (unlikely(!dl_rq->dl_nr_running))
1159 put_prev_task(rq, prev);
1161 dl_se = pick_next_dl_entity(rq, dl_rq);
1164 p = dl_task_of(dl_se);
1165 p->se.exec_start = rq_clock_task(rq);
1167 /* Running task will never be pushed. */
1168 dequeue_pushable_dl_task(rq, p);
1170 if (hrtick_enabled(rq))
1171 start_hrtick_dl(rq, p);
1173 queue_push_tasks(rq);
1178 static void put_prev_task_dl(struct rq *rq, struct task_struct *p)
1182 if (on_dl_rq(&p->dl) && tsk_nr_cpus_allowed(p) > 1)
1183 enqueue_pushable_dl_task(rq, p);
1186 static void task_tick_dl(struct rq *rq, struct task_struct *p, int queued)
1191 * Even when we have runtime, update_curr_dl() might have resulted in us
1192 * not being the leftmost task anymore. In that case NEED_RESCHED will
1193 * be set and schedule() will start a new hrtick for the next task.
1195 if (hrtick_enabled(rq) && queued && p->dl.runtime > 0 &&
1196 is_leftmost(p, &rq->dl))
1197 start_hrtick_dl(rq, p);
1200 static void task_fork_dl(struct task_struct *p)
1203 * SCHED_DEADLINE tasks cannot fork and this is achieved through
1208 static void task_dead_dl(struct task_struct *p)
1210 struct dl_bw *dl_b = dl_bw_of(task_cpu(p));
1213 * Since we are TASK_DEAD we won't slip out of the domain!
1215 raw_spin_lock_irq(&dl_b->lock);
1216 /* XXX we should retain the bw until 0-lag */
1217 dl_b->total_bw -= p->dl.dl_bw;
1218 raw_spin_unlock_irq(&dl_b->lock);
1221 static void set_curr_task_dl(struct rq *rq)
1223 struct task_struct *p = rq->curr;
1225 p->se.exec_start = rq_clock_task(rq);
1227 /* You can't push away the running task */
1228 dequeue_pushable_dl_task(rq, p);
1233 /* Only try algorithms three times */
1234 #define DL_MAX_TRIES 3
1236 static int pick_dl_task(struct rq *rq, struct task_struct *p, int cpu)
1238 if (!task_running(rq, p) &&
1239 cpumask_test_cpu(cpu, tsk_cpus_allowed(p)))
1245 * Return the earliest pushable rq's task, which is suitable to be executed
1246 * on the CPU, NULL otherwise:
1248 static struct task_struct *pick_earliest_pushable_dl_task(struct rq *rq, int cpu)
1250 struct rb_node *next_node = rq->dl.pushable_dl_tasks_leftmost;
1251 struct task_struct *p = NULL;
1253 if (!has_pushable_dl_tasks(rq))
1258 p = rb_entry(next_node, struct task_struct, pushable_dl_tasks);
1260 if (pick_dl_task(rq, p, cpu))
1263 next_node = rb_next(next_node);
1270 static DEFINE_PER_CPU(cpumask_var_t, local_cpu_mask_dl);
1272 static int find_later_rq(struct task_struct *task)
1274 struct sched_domain *sd;
1275 struct cpumask *later_mask = this_cpu_cpumask_var_ptr(local_cpu_mask_dl);
1276 int this_cpu = smp_processor_id();
1277 int best_cpu, cpu = task_cpu(task);
1279 /* Make sure the mask is initialized first */
1280 if (unlikely(!later_mask))
1283 if (tsk_nr_cpus_allowed(task) == 1)
1287 * We have to consider system topology and task affinity
1288 * first, then we can look for a suitable cpu.
1290 best_cpu = cpudl_find(&task_rq(task)->rd->cpudl,
1296 * If we are here, some target has been found,
1297 * the most suitable of which is cached in best_cpu.
1298 * This is, among the runqueues where the current tasks
1299 * have later deadlines than the task's one, the rq
1300 * with the latest possible one.
1302 * Now we check how well this matches with task's
1303 * affinity and system topology.
1305 * The last cpu where the task run is our first
1306 * guess, since it is most likely cache-hot there.
1308 if (cpumask_test_cpu(cpu, later_mask))
1311 * Check if this_cpu is to be skipped (i.e., it is
1312 * not in the mask) or not.
1314 if (!cpumask_test_cpu(this_cpu, later_mask))
1318 for_each_domain(cpu, sd) {
1319 if (sd->flags & SD_WAKE_AFFINE) {
1322 * If possible, preempting this_cpu is
1323 * cheaper than migrating.
1325 if (this_cpu != -1 &&
1326 cpumask_test_cpu(this_cpu, sched_domain_span(sd))) {
1332 * Last chance: if best_cpu is valid and is
1333 * in the mask, that becomes our choice.
1335 if (best_cpu < nr_cpu_ids &&
1336 cpumask_test_cpu(best_cpu, sched_domain_span(sd))) {
1345 * At this point, all our guesses failed, we just return
1346 * 'something', and let the caller sort the things out.
1351 cpu = cpumask_any(later_mask);
1352 if (cpu < nr_cpu_ids)
1358 /* Locks the rq it finds */
1359 static struct rq *find_lock_later_rq(struct task_struct *task, struct rq *rq)
1361 struct rq *later_rq = NULL;
1365 for (tries = 0; tries < DL_MAX_TRIES; tries++) {
1366 cpu = find_later_rq(task);
1368 if ((cpu == -1) || (cpu == rq->cpu))
1371 later_rq = cpu_rq(cpu);
1373 if (later_rq->dl.dl_nr_running &&
1374 !dl_time_before(task->dl.deadline,
1375 later_rq->dl.earliest_dl.curr)) {
1377 * Target rq has tasks of equal or earlier deadline,
1378 * retrying does not release any lock and is unlikely
1379 * to yield a different result.
1385 /* Retry if something changed. */
1386 if (double_lock_balance(rq, later_rq)) {
1387 if (unlikely(task_rq(task) != rq ||
1388 !cpumask_test_cpu(later_rq->cpu,
1389 tsk_cpus_allowed(task)) ||
1390 task_running(rq, task) ||
1392 !task_on_rq_queued(task))) {
1393 double_unlock_balance(rq, later_rq);
1400 * If the rq we found has no -deadline task, or
1401 * its earliest one has a later deadline than our
1402 * task, the rq is a good one.
1404 if (!later_rq->dl.dl_nr_running ||
1405 dl_time_before(task->dl.deadline,
1406 later_rq->dl.earliest_dl.curr))
1409 /* Otherwise we try again. */
1410 double_unlock_balance(rq, later_rq);
1417 static struct task_struct *pick_next_pushable_dl_task(struct rq *rq)
1419 struct task_struct *p;
1421 if (!has_pushable_dl_tasks(rq))
1424 p = rb_entry(rq->dl.pushable_dl_tasks_leftmost,
1425 struct task_struct, pushable_dl_tasks);
1427 BUG_ON(rq->cpu != task_cpu(p));
1428 BUG_ON(task_current(rq, p));
1429 BUG_ON(tsk_nr_cpus_allowed(p) <= 1);
1431 BUG_ON(!task_on_rq_queued(p));
1432 BUG_ON(!dl_task(p));
1438 * See if the non running -deadline tasks on this rq
1439 * can be sent to some other CPU where they can preempt
1440 * and start executing.
1442 static int push_dl_task(struct rq *rq)
1444 struct task_struct *next_task;
1445 struct rq *later_rq;
1448 if (!rq->dl.overloaded)
1451 next_task = pick_next_pushable_dl_task(rq);
1456 if (unlikely(next_task == rq->curr)) {
1462 * If next_task preempts rq->curr, and rq->curr
1463 * can move away, it makes sense to just reschedule
1464 * without going further in pushing next_task.
1466 if (dl_task(rq->curr) &&
1467 dl_time_before(next_task->dl.deadline, rq->curr->dl.deadline) &&
1468 tsk_nr_cpus_allowed(rq->curr) > 1) {
1473 /* We might release rq lock */
1474 get_task_struct(next_task);
1476 /* Will lock the rq it'll find */
1477 later_rq = find_lock_later_rq(next_task, rq);
1479 struct task_struct *task;
1482 * We must check all this again, since
1483 * find_lock_later_rq releases rq->lock and it is
1484 * then possible that next_task has migrated.
1486 task = pick_next_pushable_dl_task(rq);
1487 if (task_cpu(next_task) == rq->cpu && task == next_task) {
1489 * The task is still there. We don't try
1490 * again, some other cpu will pull it when ready.
1499 put_task_struct(next_task);
1504 deactivate_task(rq, next_task, 0);
1505 set_task_cpu(next_task, later_rq->cpu);
1506 activate_task(later_rq, next_task, 0);
1509 resched_curr(later_rq);
1511 double_unlock_balance(rq, later_rq);
1514 put_task_struct(next_task);
1519 static void push_dl_tasks(struct rq *rq)
1521 /* push_dl_task() will return true if it moved a -deadline task */
1522 while (push_dl_task(rq))
1526 static void pull_dl_task(struct rq *this_rq)
1528 int this_cpu = this_rq->cpu, cpu;
1529 struct task_struct *p;
1530 bool resched = false;
1532 u64 dmin = LONG_MAX;
1534 if (likely(!dl_overloaded(this_rq)))
1538 * Match the barrier from dl_set_overloaded; this guarantees that if we
1539 * see overloaded we must also see the dlo_mask bit.
1543 for_each_cpu(cpu, this_rq->rd->dlo_mask) {
1544 if (this_cpu == cpu)
1547 src_rq = cpu_rq(cpu);
1550 * It looks racy, abd it is! However, as in sched_rt.c,
1551 * we are fine with this.
1553 if (this_rq->dl.dl_nr_running &&
1554 dl_time_before(this_rq->dl.earliest_dl.curr,
1555 src_rq->dl.earliest_dl.next))
1558 /* Might drop this_rq->lock */
1559 double_lock_balance(this_rq, src_rq);
1562 * If there are no more pullable tasks on the
1563 * rq, we're done with it.
1565 if (src_rq->dl.dl_nr_running <= 1)
1568 p = pick_earliest_pushable_dl_task(src_rq, this_cpu);
1571 * We found a task to be pulled if:
1572 * - it preempts our current (if there's one),
1573 * - it will preempt the last one we pulled (if any).
1575 if (p && dl_time_before(p->dl.deadline, dmin) &&
1576 (!this_rq->dl.dl_nr_running ||
1577 dl_time_before(p->dl.deadline,
1578 this_rq->dl.earliest_dl.curr))) {
1579 WARN_ON(p == src_rq->curr);
1580 WARN_ON(!task_on_rq_queued(p));
1583 * Then we pull iff p has actually an earlier
1584 * deadline than the current task of its runqueue.
1586 if (dl_time_before(p->dl.deadline,
1587 src_rq->curr->dl.deadline))
1592 deactivate_task(src_rq, p, 0);
1593 set_task_cpu(p, this_cpu);
1594 activate_task(this_rq, p, 0);
1595 dmin = p->dl.deadline;
1597 /* Is there any other task even earlier? */
1600 double_unlock_balance(this_rq, src_rq);
1604 resched_curr(this_rq);
1608 * Since the task is not running and a reschedule is not going to happen
1609 * anytime soon on its runqueue, we try pushing it away now.
1611 static void task_woken_dl(struct rq *rq, struct task_struct *p)
1613 if (!task_running(rq, p) &&
1614 !test_tsk_need_resched(rq->curr) &&
1615 tsk_nr_cpus_allowed(p) > 1 &&
1616 dl_task(rq->curr) &&
1617 (tsk_nr_cpus_allowed(rq->curr) < 2 ||
1618 !dl_entity_preempt(&p->dl, &rq->curr->dl))) {
1623 static void set_cpus_allowed_dl(struct task_struct *p,
1624 const struct cpumask *new_mask)
1626 struct root_domain *src_rd;
1629 BUG_ON(!dl_task(p));
1634 * Migrating a SCHED_DEADLINE task between exclusive
1635 * cpusets (different root_domains) entails a bandwidth
1636 * update. We already made space for us in the destination
1637 * domain (see cpuset_can_attach()).
1639 if (!cpumask_intersects(src_rd->span, new_mask)) {
1640 struct dl_bw *src_dl_b;
1642 src_dl_b = dl_bw_of(cpu_of(rq));
1644 * We now free resources of the root_domain we are migrating
1645 * off. In the worst case, sched_setattr() may temporary fail
1646 * until we complete the update.
1648 raw_spin_lock(&src_dl_b->lock);
1649 __dl_clear(src_dl_b, p->dl.dl_bw);
1650 raw_spin_unlock(&src_dl_b->lock);
1653 set_cpus_allowed_common(p, new_mask);
1656 /* Assumes rq->lock is held */
1657 static void rq_online_dl(struct rq *rq)
1659 if (rq->dl.overloaded)
1660 dl_set_overload(rq);
1662 cpudl_set_freecpu(&rq->rd->cpudl, rq->cpu);
1663 if (rq->dl.dl_nr_running > 0)
1664 cpudl_set(&rq->rd->cpudl, rq->cpu, rq->dl.earliest_dl.curr);
1667 /* Assumes rq->lock is held */
1668 static void rq_offline_dl(struct rq *rq)
1670 if (rq->dl.overloaded)
1671 dl_clear_overload(rq);
1673 cpudl_clear(&rq->rd->cpudl, rq->cpu);
1674 cpudl_clear_freecpu(&rq->rd->cpudl, rq->cpu);
1677 void __init init_sched_dl_class(void)
1681 for_each_possible_cpu(i)
1682 zalloc_cpumask_var_node(&per_cpu(local_cpu_mask_dl, i),
1683 GFP_KERNEL, cpu_to_node(i));
1686 #endif /* CONFIG_SMP */
1688 static void switched_from_dl(struct rq *rq, struct task_struct *p)
1691 * Start the deadline timer; if we switch back to dl before this we'll
1692 * continue consuming our current CBS slice. If we stay outside of
1693 * SCHED_DEADLINE until the deadline passes, the timer will reset the
1696 if (!start_dl_timer(p))
1697 __dl_clear_params(p);
1700 * Since this might be the only -deadline task on the rq,
1701 * this is the right place to try to pull some other one
1702 * from an overloaded cpu, if any.
1704 if (!task_on_rq_queued(p) || rq->dl.dl_nr_running)
1707 queue_pull_task(rq);
1711 * When switching to -deadline, we may overload the rq, then
1712 * we try to push someone off, if possible.
1714 static void switched_to_dl(struct rq *rq, struct task_struct *p)
1717 /* If p is not queued we will update its parameters at next wakeup. */
1718 if (!task_on_rq_queued(p))
1722 * If p is boosted we already updated its params in
1723 * rt_mutex_setprio()->enqueue_task(..., ENQUEUE_REPLENISH),
1724 * p's deadline being now already after rq_clock(rq).
1726 if (dl_time_before(p->dl.deadline, rq_clock(rq)))
1727 setup_new_dl_entity(&p->dl);
1729 if (rq->curr != p) {
1731 if (tsk_nr_cpus_allowed(p) > 1 && rq->dl.overloaded)
1732 queue_push_tasks(rq);
1734 if (dl_task(rq->curr))
1735 check_preempt_curr_dl(rq, p, 0);
1743 * If the scheduling parameters of a -deadline task changed,
1744 * a push or pull operation might be needed.
1746 static void prio_changed_dl(struct rq *rq, struct task_struct *p,
1749 if (task_on_rq_queued(p) || rq->curr == p) {
1752 * This might be too much, but unfortunately
1753 * we don't have the old deadline value, and
1754 * we can't argue if the task is increasing
1755 * or lowering its prio, so...
1757 if (!rq->dl.overloaded)
1758 queue_pull_task(rq);
1761 * If we now have a earlier deadline task than p,
1762 * then reschedule, provided p is still on this
1765 if (dl_time_before(rq->dl.earliest_dl.curr, p->dl.deadline))
1769 * Again, we don't know if p has a earlier
1770 * or later deadline, so let's blindly set a
1771 * (maybe not needed) rescheduling point.
1774 #endif /* CONFIG_SMP */
1778 const struct sched_class dl_sched_class = {
1779 .next = &rt_sched_class,
1780 .enqueue_task = enqueue_task_dl,
1781 .dequeue_task = dequeue_task_dl,
1782 .yield_task = yield_task_dl,
1784 .check_preempt_curr = check_preempt_curr_dl,
1786 .pick_next_task = pick_next_task_dl,
1787 .put_prev_task = put_prev_task_dl,
1790 .select_task_rq = select_task_rq_dl,
1791 .set_cpus_allowed = set_cpus_allowed_dl,
1792 .rq_online = rq_online_dl,
1793 .rq_offline = rq_offline_dl,
1794 .task_woken = task_woken_dl,
1797 .set_curr_task = set_curr_task_dl,
1798 .task_tick = task_tick_dl,
1799 .task_fork = task_fork_dl,
1800 .task_dead = task_dead_dl,
1802 .prio_changed = prio_changed_dl,
1803 .switched_from = switched_from_dl,
1804 .switched_to = switched_to_dl,
1806 .update_curr = update_curr_dl,
1809 #ifdef CONFIG_SCHED_DEBUG
1810 extern void print_dl_rq(struct seq_file *m, int cpu, struct dl_rq *dl_rq);
1812 void print_dl_stats(struct seq_file *m, int cpu)
1814 print_dl_rq(m, cpu, &cpu_rq(cpu)->dl);
1816 #endif /* CONFIG_SCHED_DEBUG */