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
, struct rq
*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_setscheduler_ex().
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
;
356 * Here we check if --at time t-- an entity (which is probably being
357 * [re]activated or, in general, enqueued) can use its remaining runtime
358 * and its current deadline _without_ exceeding the bandwidth it is
359 * assigned (function returns true if it can't). We are in fact applying
360 * one of the CBS rules: when a task wakes up, if the residual runtime
361 * over residual deadline fits within the allocated bandwidth, then we
362 * can keep the current (absolute) deadline and residual budget without
363 * disrupting the schedulability of the system. Otherwise, we should
364 * refill the runtime and set the deadline a period in the future,
365 * because keeping the current (absolute) deadline of the task would
366 * result in breaking guarantees promised to other tasks (refer to
367 * Documentation/scheduler/sched-deadline.txt for more informations).
369 * This function returns true if:
371 * runtime / (deadline - t) > dl_runtime / dl_period ,
373 * IOW we can't recycle current parameters.
375 * Notice that the bandwidth check is done against the period. For
376 * task with deadline equal to period this is the same of using
377 * dl_deadline instead of dl_period in the equation above.
379 static bool dl_entity_overflow(struct sched_dl_entity
*dl_se
,
380 struct sched_dl_entity
*pi_se
, u64 t
)
385 * left and right are the two sides of the equation above,
386 * after a bit of shuffling to use multiplications instead
389 * Note that none of the time values involved in the two
390 * multiplications are absolute: dl_deadline and dl_runtime
391 * are the relative deadline and the maximum runtime of each
392 * instance, runtime is the runtime left for the last instance
393 * and (deadline - t), since t is rq->clock, is the time left
394 * to the (absolute) deadline. Even if overflowing the u64 type
395 * is very unlikely to occur in both cases, here we scale down
396 * as we want to avoid that risk at all. Scaling down by 10
397 * means that we reduce granularity to 1us. We are fine with it,
398 * since this is only a true/false check and, anyway, thinking
399 * of anything below microseconds resolution is actually fiction
400 * (but still we want to give the user that illusion >;).
402 left
= (pi_se
->dl_period
>> DL_SCALE
) * (dl_se
->runtime
>> DL_SCALE
);
403 right
= ((dl_se
->deadline
- t
) >> DL_SCALE
) *
404 (pi_se
->dl_runtime
>> DL_SCALE
);
406 return dl_time_before(right
, left
);
410 * When a -deadline entity is queued back on the runqueue, its runtime and
411 * deadline might need updating.
413 * The policy here is that we update the deadline of the entity only if:
414 * - the current deadline is in the past,
415 * - using the remaining runtime with the current deadline would make
416 * the entity exceed its bandwidth.
418 static void update_dl_entity(struct sched_dl_entity
*dl_se
,
419 struct sched_dl_entity
*pi_se
)
421 struct dl_rq
*dl_rq
= dl_rq_of_se(dl_se
);
422 struct rq
*rq
= rq_of_dl_rq(dl_rq
);
425 * The arrival of a new instance needs special treatment, i.e.,
426 * the actual scheduling parameters have to be "renewed".
429 setup_new_dl_entity(dl_se
, pi_se
);
433 if (dl_time_before(dl_se
->deadline
, rq_clock(rq
)) ||
434 dl_entity_overflow(dl_se
, pi_se
, rq_clock(rq
))) {
435 dl_se
->deadline
= rq_clock(rq
) + pi_se
->dl_deadline
;
436 dl_se
->runtime
= pi_se
->dl_runtime
;
441 * If the entity depleted all its runtime, and if we want it to sleep
442 * while waiting for some new execution time to become available, we
443 * set the bandwidth enforcement timer to the replenishment instant
444 * and try to activate it.
446 * Notice that it is important for the caller to know if the timer
447 * actually started or not (i.e., the replenishment instant is in
448 * the future or in the past).
450 static int start_dl_timer(struct sched_dl_entity
*dl_se
, bool boosted
)
452 struct dl_rq
*dl_rq
= dl_rq_of_se(dl_se
);
453 struct rq
*rq
= rq_of_dl_rq(dl_rq
);
462 * We want the timer to fire at the deadline, but considering
463 * that it is actually coming from rq->clock and not from
464 * hrtimer's time base reading.
466 act
= ns_to_ktime(dl_se
->deadline
);
467 now
= hrtimer_cb_get_time(&dl_se
->dl_timer
);
468 delta
= ktime_to_ns(now
) - rq_clock(rq
);
469 act
= ktime_add_ns(act
, delta
);
472 * If the expiry time already passed, e.g., because the value
473 * chosen as the deadline is too small, don't even try to
474 * start the timer in the past!
476 if (ktime_us_delta(act
, now
) < 0)
479 hrtimer_set_expires(&dl_se
->dl_timer
, act
);
481 soft
= hrtimer_get_softexpires(&dl_se
->dl_timer
);
482 hard
= hrtimer_get_expires(&dl_se
->dl_timer
);
483 range
= ktime_to_ns(ktime_sub(hard
, soft
));
484 __hrtimer_start_range_ns(&dl_se
->dl_timer
, soft
,
485 range
, HRTIMER_MODE_ABS
, 0);
487 return hrtimer_active(&dl_se
->dl_timer
);
491 * This is the bandwidth enforcement timer callback. If here, we know
492 * a task is not on its dl_rq, since the fact that the timer was running
493 * means the task is throttled and needs a runtime replenishment.
495 * However, what we actually do depends on the fact the task is active,
496 * (it is on its rq) or has been removed from there by a call to
497 * dequeue_task_dl(). In the former case we must issue the runtime
498 * replenishment and add the task back to the dl_rq; in the latter, we just
499 * do nothing but clearing dl_throttled, so that runtime and deadline
500 * updating (and the queueing back to dl_rq) will be done by the
501 * next call to enqueue_task_dl().
503 static enum hrtimer_restart
dl_task_timer(struct hrtimer
*timer
)
505 struct sched_dl_entity
*dl_se
= container_of(timer
,
506 struct sched_dl_entity
,
508 struct task_struct
*p
= dl_task_of(dl_se
);
512 raw_spin_lock(&rq
->lock
);
514 if (rq
!= task_rq(p
)) {
515 /* Task was moved, retrying. */
516 raw_spin_unlock(&rq
->lock
);
521 * We need to take care of a possible races here. In fact, the
522 * task might have changed its scheduling policy to something
523 * different from SCHED_DEADLINE or changed its reservation
524 * parameters (through sched_setattr()).
526 if (!dl_task(p
) || dl_se
->dl_new
)
531 dl_se
->dl_throttled
= 0;
532 dl_se
->dl_yielded
= 0;
534 enqueue_task_dl(rq
, p
, ENQUEUE_REPLENISH
);
535 if (task_has_dl_policy(rq
->curr
))
536 check_preempt_curr_dl(rq
, p
, 0);
538 resched_task(rq
->curr
);
541 * Queueing this task back might have overloaded rq,
542 * check if we need to kick someone away.
544 if (has_pushable_dl_tasks(rq
))
549 raw_spin_unlock(&rq
->lock
);
551 return HRTIMER_NORESTART
;
554 void init_dl_task_timer(struct sched_dl_entity
*dl_se
)
556 struct hrtimer
*timer
= &dl_se
->dl_timer
;
558 if (hrtimer_active(timer
)) {
559 hrtimer_try_to_cancel(timer
);
563 hrtimer_init(timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
564 timer
->function
= dl_task_timer
;
568 int dl_runtime_exceeded(struct rq
*rq
, struct sched_dl_entity
*dl_se
)
570 int dmiss
= dl_time_before(dl_se
->deadline
, rq_clock(rq
));
571 int rorun
= dl_se
->runtime
<= 0;
573 if (!rorun
&& !dmiss
)
577 * If we are beyond our current deadline and we are still
578 * executing, then we have already used some of the runtime of
579 * the next instance. Thus, if we do not account that, we are
580 * stealing bandwidth from the system at each deadline miss!
583 dl_se
->runtime
= rorun
? dl_se
->runtime
: 0;
584 dl_se
->runtime
-= rq_clock(rq
) - dl_se
->deadline
;
590 extern bool sched_rt_bandwidth_account(struct rt_rq
*rt_rq
);
593 * Update the current task's runtime statistics (provided it is still
594 * a -deadline task and has not been removed from the dl_rq).
596 static void update_curr_dl(struct rq
*rq
)
598 struct task_struct
*curr
= rq
->curr
;
599 struct sched_dl_entity
*dl_se
= &curr
->dl
;
602 if (!dl_task(curr
) || !on_dl_rq(dl_se
))
606 * Consumed budget is computed considering the time as
607 * observed by schedulable tasks (excluding time spent
608 * in hardirq context, etc.). Deadlines are instead
609 * computed using hard walltime. This seems to be the more
610 * natural solution, but the full ramifications of this
611 * approach need further study.
613 delta_exec
= rq_clock_task(rq
) - curr
->se
.exec_start
;
614 if (unlikely((s64
)delta_exec
<= 0))
617 schedstat_set(curr
->se
.statistics
.exec_max
,
618 max(curr
->se
.statistics
.exec_max
, delta_exec
));
620 curr
->se
.sum_exec_runtime
+= delta_exec
;
621 account_group_exec_runtime(curr
, delta_exec
);
623 curr
->se
.exec_start
= rq_clock_task(rq
);
624 cpuacct_charge(curr
, delta_exec
);
626 sched_rt_avg_update(rq
, delta_exec
);
628 dl_se
->runtime
-= delta_exec
;
629 if (dl_runtime_exceeded(rq
, dl_se
)) {
630 __dequeue_task_dl(rq
, curr
, 0);
631 if (likely(start_dl_timer(dl_se
, curr
->dl
.dl_boosted
)))
632 dl_se
->dl_throttled
= 1;
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_REPLENISH
)
827 replenish_dl_entity(dl_se
, pi_se
);
829 update_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
;
854 * If p is throttled, we do nothing. In fact, if it exhausted
855 * its budget it needs a replenishment and, since it now is on
856 * its rq, the bandwidth timer callback (which clearly has not
857 * run yet) will take care of this.
859 if (p
->dl
.dl_throttled
)
862 enqueue_dl_entity(&p
->dl
, pi_se
, flags
);
864 if (!task_current(rq
, p
) && p
->nr_cpus_allowed
> 1)
865 enqueue_pushable_dl_task(rq
, p
);
868 static void __dequeue_task_dl(struct rq
*rq
, struct task_struct
*p
, int flags
)
870 dequeue_dl_entity(&p
->dl
);
871 dequeue_pushable_dl_task(rq
, p
);
874 static void dequeue_task_dl(struct rq
*rq
, struct task_struct
*p
, int flags
)
877 __dequeue_task_dl(rq
, p
, flags
);
881 * Yield task semantic for -deadline tasks is:
883 * get off from the CPU until our next instance, with
884 * a new runtime. This is of little use now, since we
885 * don't have a bandwidth reclaiming mechanism. Anyway,
886 * bandwidth reclaiming is planned for the future, and
887 * yield_task_dl will indicate that some spare budget
888 * is available for other task instances to use it.
890 static void yield_task_dl(struct rq
*rq
)
892 struct task_struct
*p
= rq
->curr
;
895 * We make the task go to sleep until its current deadline by
896 * forcing its runtime to zero. This way, update_curr_dl() stops
897 * it and the bandwidth timer will wake it up and will give it
898 * new scheduling parameters (thanks to dl_yielded=1).
900 if (p
->dl
.runtime
> 0) {
901 rq
->curr
->dl
.dl_yielded
= 1;
909 static int find_later_rq(struct task_struct
*task
);
912 select_task_rq_dl(struct task_struct
*p
, int cpu
, int sd_flag
, int flags
)
914 struct task_struct
*curr
;
917 if (sd_flag
!= SD_BALANCE_WAKE
&& sd_flag
!= SD_BALANCE_FORK
)
923 curr
= ACCESS_ONCE(rq
->curr
); /* unlocked access */
926 * If we are dealing with a -deadline task, we must
927 * decide where to wake it up.
928 * If it has a later deadline and the current task
929 * on this rq can't move (provided the waking task
930 * can!) we prefer to send it somewhere else. On the
931 * other hand, if it has a shorter deadline, we
932 * try to make it stay here, it might be important.
934 if (unlikely(dl_task(curr
)) &&
935 (curr
->nr_cpus_allowed
< 2 ||
936 !dl_entity_preempt(&p
->dl
, &curr
->dl
)) &&
937 (p
->nr_cpus_allowed
> 1)) {
938 int target
= find_later_rq(p
);
949 static void check_preempt_equal_dl(struct rq
*rq
, struct task_struct
*p
)
952 * Current can't be migrated, useless to reschedule,
953 * let's hope p can move out.
955 if (rq
->curr
->nr_cpus_allowed
== 1 ||
956 cpudl_find(&rq
->rd
->cpudl
, rq
->curr
, NULL
) == -1)
960 * p is migratable, so let's not schedule it and
961 * see if it is pushed or pulled somewhere else.
963 if (p
->nr_cpus_allowed
!= 1 &&
964 cpudl_find(&rq
->rd
->cpudl
, p
, NULL
) != -1)
967 resched_task(rq
->curr
);
970 static int pull_dl_task(struct rq
*this_rq
);
972 #endif /* CONFIG_SMP */
975 * Only called when both the current and waking task are -deadline
978 static void check_preempt_curr_dl(struct rq
*rq
, struct task_struct
*p
,
981 if (dl_entity_preempt(&p
->dl
, &rq
->curr
->dl
)) {
982 resched_task(rq
->curr
);
988 * In the unlikely case current and p have the same deadline
989 * let us try to decide what's the best thing to do...
991 if ((p
->dl
.deadline
== rq
->curr
->dl
.deadline
) &&
992 !test_tsk_need_resched(rq
->curr
))
993 check_preempt_equal_dl(rq
, p
);
994 #endif /* CONFIG_SMP */
997 #ifdef CONFIG_SCHED_HRTICK
998 static void start_hrtick_dl(struct rq
*rq
, struct task_struct
*p
)
1000 s64 delta
= p
->dl
.dl_runtime
- p
->dl
.runtime
;
1003 hrtick_start(rq
, p
->dl
.runtime
);
1007 static struct sched_dl_entity
*pick_next_dl_entity(struct rq
*rq
,
1008 struct dl_rq
*dl_rq
)
1010 struct rb_node
*left
= dl_rq
->rb_leftmost
;
1015 return rb_entry(left
, struct sched_dl_entity
, rb_node
);
1018 struct task_struct
*pick_next_task_dl(struct rq
*rq
, struct task_struct
*prev
)
1020 struct sched_dl_entity
*dl_se
;
1021 struct task_struct
*p
;
1022 struct dl_rq
*dl_rq
;
1026 if (need_pull_dl_task(rq
, prev
)) {
1029 * pull_rt_task() can drop (and re-acquire) rq->lock; this
1030 * means a stop task can slip in, in which case we need to
1031 * re-start task selection.
1033 if (rq
->stop
&& rq
->stop
->on_rq
)
1038 * When prev is DL, we may throttle it in put_prev_task().
1039 * So, we update time before we check for dl_nr_running.
1041 if (prev
->sched_class
== &dl_sched_class
)
1044 if (unlikely(!dl_rq
->dl_nr_running
))
1047 put_prev_task(rq
, prev
);
1049 dl_se
= pick_next_dl_entity(rq
, dl_rq
);
1052 p
= dl_task_of(dl_se
);
1053 p
->se
.exec_start
= rq_clock_task(rq
);
1055 /* Running task will never be pushed. */
1056 dequeue_pushable_dl_task(rq
, p
);
1058 #ifdef CONFIG_SCHED_HRTICK
1059 if (hrtick_enabled(rq
))
1060 start_hrtick_dl(rq
, p
);
1063 set_post_schedule(rq
);
1068 static void put_prev_task_dl(struct rq
*rq
, struct task_struct
*p
)
1072 if (on_dl_rq(&p
->dl
) && p
->nr_cpus_allowed
> 1)
1073 enqueue_pushable_dl_task(rq
, p
);
1076 static void task_tick_dl(struct rq
*rq
, struct task_struct
*p
, int queued
)
1080 #ifdef CONFIG_SCHED_HRTICK
1081 if (hrtick_enabled(rq
) && queued
&& p
->dl
.runtime
> 0)
1082 start_hrtick_dl(rq
, p
);
1086 static void task_fork_dl(struct task_struct
*p
)
1089 * SCHED_DEADLINE tasks cannot fork and this is achieved through
1094 static void task_dead_dl(struct task_struct
*p
)
1096 struct hrtimer
*timer
= &p
->dl
.dl_timer
;
1097 struct dl_bw
*dl_b
= dl_bw_of(task_cpu(p
));
1100 * Since we are TASK_DEAD we won't slip out of the domain!
1102 raw_spin_lock_irq(&dl_b
->lock
);
1103 dl_b
->total_bw
-= p
->dl
.dl_bw
;
1104 raw_spin_unlock_irq(&dl_b
->lock
);
1106 hrtimer_cancel(timer
);
1109 static void set_curr_task_dl(struct rq
*rq
)
1111 struct task_struct
*p
= rq
->curr
;
1113 p
->se
.exec_start
= rq_clock_task(rq
);
1115 /* You can't push away the running task */
1116 dequeue_pushable_dl_task(rq
, p
);
1121 /* Only try algorithms three times */
1122 #define DL_MAX_TRIES 3
1124 static int pick_dl_task(struct rq
*rq
, struct task_struct
*p
, int cpu
)
1126 if (!task_running(rq
, p
) &&
1127 (cpu
< 0 || cpumask_test_cpu(cpu
, &p
->cpus_allowed
)) &&
1128 (p
->nr_cpus_allowed
> 1))
1134 /* Returns the second earliest -deadline task, NULL otherwise */
1135 static struct task_struct
*pick_next_earliest_dl_task(struct rq
*rq
, int cpu
)
1137 struct rb_node
*next_node
= rq
->dl
.rb_leftmost
;
1138 struct sched_dl_entity
*dl_se
;
1139 struct task_struct
*p
= NULL
;
1142 next_node
= rb_next(next_node
);
1144 dl_se
= rb_entry(next_node
, struct sched_dl_entity
, rb_node
);
1145 p
= dl_task_of(dl_se
);
1147 if (pick_dl_task(rq
, p
, cpu
))
1156 static DEFINE_PER_CPU(cpumask_var_t
, local_cpu_mask_dl
);
1158 static int find_later_rq(struct task_struct
*task
)
1160 struct sched_domain
*sd
;
1161 struct cpumask
*later_mask
= __get_cpu_var(local_cpu_mask_dl
);
1162 int this_cpu
= smp_processor_id();
1163 int best_cpu
, cpu
= task_cpu(task
);
1165 /* Make sure the mask is initialized first */
1166 if (unlikely(!later_mask
))
1169 if (task
->nr_cpus_allowed
== 1)
1172 best_cpu
= cpudl_find(&task_rq(task
)->rd
->cpudl
,
1178 * If we are here, some target has been found,
1179 * the most suitable of which is cached in best_cpu.
1180 * This is, among the runqueues where the current tasks
1181 * have later deadlines than the task's one, the rq
1182 * with the latest possible one.
1184 * Now we check how well this matches with task's
1185 * affinity and system topology.
1187 * The last cpu where the task run is our first
1188 * guess, since it is most likely cache-hot there.
1190 if (cpumask_test_cpu(cpu
, later_mask
))
1193 * Check if this_cpu is to be skipped (i.e., it is
1194 * not in the mask) or not.
1196 if (!cpumask_test_cpu(this_cpu
, later_mask
))
1200 for_each_domain(cpu
, sd
) {
1201 if (sd
->flags
& SD_WAKE_AFFINE
) {
1204 * If possible, preempting this_cpu is
1205 * cheaper than migrating.
1207 if (this_cpu
!= -1 &&
1208 cpumask_test_cpu(this_cpu
, sched_domain_span(sd
))) {
1214 * Last chance: if best_cpu is valid and is
1215 * in the mask, that becomes our choice.
1217 if (best_cpu
< nr_cpu_ids
&&
1218 cpumask_test_cpu(best_cpu
, sched_domain_span(sd
))) {
1227 * At this point, all our guesses failed, we just return
1228 * 'something', and let the caller sort the things out.
1233 cpu
= cpumask_any(later_mask
);
1234 if (cpu
< nr_cpu_ids
)
1240 /* Locks the rq it finds */
1241 static struct rq
*find_lock_later_rq(struct task_struct
*task
, struct rq
*rq
)
1243 struct rq
*later_rq
= NULL
;
1247 for (tries
= 0; tries
< DL_MAX_TRIES
; tries
++) {
1248 cpu
= find_later_rq(task
);
1250 if ((cpu
== -1) || (cpu
== rq
->cpu
))
1253 later_rq
= cpu_rq(cpu
);
1255 /* Retry if something changed. */
1256 if (double_lock_balance(rq
, later_rq
)) {
1257 if (unlikely(task_rq(task
) != rq
||
1258 !cpumask_test_cpu(later_rq
->cpu
,
1259 &task
->cpus_allowed
) ||
1260 task_running(rq
, task
) || !task
->on_rq
)) {
1261 double_unlock_balance(rq
, later_rq
);
1268 * If the rq we found has no -deadline task, or
1269 * its earliest one has a later deadline than our
1270 * task, the rq is a good one.
1272 if (!later_rq
->dl
.dl_nr_running
||
1273 dl_time_before(task
->dl
.deadline
,
1274 later_rq
->dl
.earliest_dl
.curr
))
1277 /* Otherwise we try again. */
1278 double_unlock_balance(rq
, later_rq
);
1285 static struct task_struct
*pick_next_pushable_dl_task(struct rq
*rq
)
1287 struct task_struct
*p
;
1289 if (!has_pushable_dl_tasks(rq
))
1292 p
= rb_entry(rq
->dl
.pushable_dl_tasks_leftmost
,
1293 struct task_struct
, pushable_dl_tasks
);
1295 BUG_ON(rq
->cpu
!= task_cpu(p
));
1296 BUG_ON(task_current(rq
, p
));
1297 BUG_ON(p
->nr_cpus_allowed
<= 1);
1300 BUG_ON(!dl_task(p
));
1306 * See if the non running -deadline tasks on this rq
1307 * can be sent to some other CPU where they can preempt
1308 * and start executing.
1310 static int push_dl_task(struct rq
*rq
)
1312 struct task_struct
*next_task
;
1313 struct rq
*later_rq
;
1315 if (!rq
->dl
.overloaded
)
1318 next_task
= pick_next_pushable_dl_task(rq
);
1323 if (unlikely(next_task
== rq
->curr
)) {
1329 * If next_task preempts rq->curr, and rq->curr
1330 * can move away, it makes sense to just reschedule
1331 * without going further in pushing next_task.
1333 if (dl_task(rq
->curr
) &&
1334 dl_time_before(next_task
->dl
.deadline
, rq
->curr
->dl
.deadline
) &&
1335 rq
->curr
->nr_cpus_allowed
> 1) {
1336 resched_task(rq
->curr
);
1340 /* We might release rq lock */
1341 get_task_struct(next_task
);
1343 /* Will lock the rq it'll find */
1344 later_rq
= find_lock_later_rq(next_task
, rq
);
1346 struct task_struct
*task
;
1349 * We must check all this again, since
1350 * find_lock_later_rq releases rq->lock and it is
1351 * then possible that next_task has migrated.
1353 task
= pick_next_pushable_dl_task(rq
);
1354 if (task_cpu(next_task
) == rq
->cpu
&& task
== next_task
) {
1356 * The task is still there. We don't try
1357 * again, some other cpu will pull it when ready.
1359 dequeue_pushable_dl_task(rq
, next_task
);
1367 put_task_struct(next_task
);
1372 deactivate_task(rq
, next_task
, 0);
1373 set_task_cpu(next_task
, later_rq
->cpu
);
1374 activate_task(later_rq
, next_task
, 0);
1376 resched_task(later_rq
->curr
);
1378 double_unlock_balance(rq
, later_rq
);
1381 put_task_struct(next_task
);
1386 static void push_dl_tasks(struct rq
*rq
)
1388 /* Terminates as it moves a -deadline task */
1389 while (push_dl_task(rq
))
1393 static int pull_dl_task(struct rq
*this_rq
)
1395 int this_cpu
= this_rq
->cpu
, ret
= 0, cpu
;
1396 struct task_struct
*p
;
1398 u64 dmin
= LONG_MAX
;
1400 if (likely(!dl_overloaded(this_rq
)))
1404 * Match the barrier from dl_set_overloaded; this guarantees that if we
1405 * see overloaded we must also see the dlo_mask bit.
1409 for_each_cpu(cpu
, this_rq
->rd
->dlo_mask
) {
1410 if (this_cpu
== cpu
)
1413 src_rq
= cpu_rq(cpu
);
1416 * It looks racy, abd it is! However, as in sched_rt.c,
1417 * we are fine with this.
1419 if (this_rq
->dl
.dl_nr_running
&&
1420 dl_time_before(this_rq
->dl
.earliest_dl
.curr
,
1421 src_rq
->dl
.earliest_dl
.next
))
1424 /* Might drop this_rq->lock */
1425 double_lock_balance(this_rq
, src_rq
);
1428 * If there are no more pullable tasks on the
1429 * rq, we're done with it.
1431 if (src_rq
->dl
.dl_nr_running
<= 1)
1434 p
= pick_next_earliest_dl_task(src_rq
, this_cpu
);
1437 * We found a task to be pulled if:
1438 * - it preempts our current (if there's one),
1439 * - it will preempt the last one we pulled (if any).
1441 if (p
&& dl_time_before(p
->dl
.deadline
, dmin
) &&
1442 (!this_rq
->dl
.dl_nr_running
||
1443 dl_time_before(p
->dl
.deadline
,
1444 this_rq
->dl
.earliest_dl
.curr
))) {
1445 WARN_ON(p
== src_rq
->curr
);
1449 * Then we pull iff p has actually an earlier
1450 * deadline than the current task of its runqueue.
1452 if (dl_time_before(p
->dl
.deadline
,
1453 src_rq
->curr
->dl
.deadline
))
1458 deactivate_task(src_rq
, p
, 0);
1459 set_task_cpu(p
, this_cpu
);
1460 activate_task(this_rq
, p
, 0);
1461 dmin
= p
->dl
.deadline
;
1463 /* Is there any other task even earlier? */
1466 double_unlock_balance(this_rq
, src_rq
);
1472 static void post_schedule_dl(struct rq
*rq
)
1478 * Since the task is not running and a reschedule is not going to happen
1479 * anytime soon on its runqueue, we try pushing it away now.
1481 static void task_woken_dl(struct rq
*rq
, struct task_struct
*p
)
1483 if (!task_running(rq
, p
) &&
1484 !test_tsk_need_resched(rq
->curr
) &&
1485 has_pushable_dl_tasks(rq
) &&
1486 p
->nr_cpus_allowed
> 1 &&
1487 dl_task(rq
->curr
) &&
1488 (rq
->curr
->nr_cpus_allowed
< 2 ||
1489 dl_entity_preempt(&rq
->curr
->dl
, &p
->dl
))) {
1494 static void set_cpus_allowed_dl(struct task_struct
*p
,
1495 const struct cpumask
*new_mask
)
1500 BUG_ON(!dl_task(p
));
1503 * Update only if the task is actually running (i.e.,
1504 * it is on the rq AND it is not throttled).
1506 if (!on_dl_rq(&p
->dl
))
1509 weight
= cpumask_weight(new_mask
);
1512 * Only update if the process changes its state from whether it
1513 * can migrate or not.
1515 if ((p
->nr_cpus_allowed
> 1) == (weight
> 1))
1521 * The process used to be able to migrate OR it can now migrate
1524 if (!task_current(rq
, p
))
1525 dequeue_pushable_dl_task(rq
, p
);
1526 BUG_ON(!rq
->dl
.dl_nr_migratory
);
1527 rq
->dl
.dl_nr_migratory
--;
1529 if (!task_current(rq
, p
))
1530 enqueue_pushable_dl_task(rq
, p
);
1531 rq
->dl
.dl_nr_migratory
++;
1534 update_dl_migration(&rq
->dl
);
1537 /* Assumes rq->lock is held */
1538 static void rq_online_dl(struct rq
*rq
)
1540 if (rq
->dl
.overloaded
)
1541 dl_set_overload(rq
);
1543 if (rq
->dl
.dl_nr_running
> 0)
1544 cpudl_set(&rq
->rd
->cpudl
, rq
->cpu
, rq
->dl
.earliest_dl
.curr
, 1);
1547 /* Assumes rq->lock is held */
1548 static void rq_offline_dl(struct rq
*rq
)
1550 if (rq
->dl
.overloaded
)
1551 dl_clear_overload(rq
);
1553 cpudl_set(&rq
->rd
->cpudl
, rq
->cpu
, 0, 0);
1556 void init_sched_dl_class(void)
1560 for_each_possible_cpu(i
)
1561 zalloc_cpumask_var_node(&per_cpu(local_cpu_mask_dl
, i
),
1562 GFP_KERNEL
, cpu_to_node(i
));
1565 #endif /* CONFIG_SMP */
1567 static void switched_from_dl(struct rq
*rq
, struct task_struct
*p
)
1569 if (hrtimer_active(&p
->dl
.dl_timer
) && !dl_policy(p
->policy
))
1570 hrtimer_try_to_cancel(&p
->dl
.dl_timer
);
1574 * Since this might be the only -deadline task on the rq,
1575 * this is the right place to try to pull some other one
1576 * from an overloaded cpu, if any.
1578 if (!rq
->dl
.dl_nr_running
)
1584 * When switching to -deadline, we may overload the rq, then
1585 * we try to push someone off, if possible.
1587 static void switched_to_dl(struct rq
*rq
, struct task_struct
*p
)
1589 int check_resched
= 1;
1592 * If p is throttled, don't consider the possibility
1593 * of preempting rq->curr, the check will be done right
1594 * after its runtime will get replenished.
1596 if (unlikely(p
->dl
.dl_throttled
))
1599 if (p
->on_rq
&& rq
->curr
!= p
) {
1601 if (rq
->dl
.overloaded
&& push_dl_task(rq
) && rq
!= task_rq(p
))
1602 /* Only reschedule if pushing failed */
1604 #endif /* CONFIG_SMP */
1605 if (check_resched
&& task_has_dl_policy(rq
->curr
))
1606 check_preempt_curr_dl(rq
, p
, 0);
1611 * If the scheduling parameters of a -deadline task changed,
1612 * a push or pull operation might be needed.
1614 static void prio_changed_dl(struct rq
*rq
, struct task_struct
*p
,
1617 if (p
->on_rq
|| rq
->curr
== p
) {
1620 * This might be too much, but unfortunately
1621 * we don't have the old deadline value, and
1622 * we can't argue if the task is increasing
1623 * or lowering its prio, so...
1625 if (!rq
->dl
.overloaded
)
1629 * If we now have a earlier deadline task than p,
1630 * then reschedule, provided p is still on this
1633 if (dl_time_before(rq
->dl
.earliest_dl
.curr
, p
->dl
.deadline
) &&
1638 * Again, we don't know if p has a earlier
1639 * or later deadline, so let's blindly set a
1640 * (maybe not needed) rescheduling point.
1643 #endif /* CONFIG_SMP */
1645 switched_to_dl(rq
, p
);
1648 const struct sched_class dl_sched_class
= {
1649 .next
= &rt_sched_class
,
1650 .enqueue_task
= enqueue_task_dl
,
1651 .dequeue_task
= dequeue_task_dl
,
1652 .yield_task
= yield_task_dl
,
1654 .check_preempt_curr
= check_preempt_curr_dl
,
1656 .pick_next_task
= pick_next_task_dl
,
1657 .put_prev_task
= put_prev_task_dl
,
1660 .select_task_rq
= select_task_rq_dl
,
1661 .set_cpus_allowed
= set_cpus_allowed_dl
,
1662 .rq_online
= rq_online_dl
,
1663 .rq_offline
= rq_offline_dl
,
1664 .post_schedule
= post_schedule_dl
,
1665 .task_woken
= task_woken_dl
,
1668 .set_curr_task
= set_curr_task_dl
,
1669 .task_tick
= task_tick_dl
,
1670 .task_fork
= task_fork_dl
,
1671 .task_dead
= task_dead_dl
,
1673 .prio_changed
= prio_changed_dl
,
1674 .switched_from
= switched_from_dl
,
1675 .switched_to
= switched_to_dl
,