sched: wakeup preempt when small overlap
[linux-2.6.git] / kernel / sched_rt.c
1 /*
2  * Real-Time Scheduling Class (mapped to the SCHED_FIFO and SCHED_RR
3  * policies)
4  */
5
6 #ifdef CONFIG_SMP
7
8 static inline int rt_overloaded(struct rq *rq)
9 {
10         return atomic_read(&rq->rd->rto_count);
11 }
12
13 static inline void rt_set_overload(struct rq *rq)
14 {
15         if (!rq->online)
16                 return;
17
18         cpu_set(rq->cpu, rq->rd->rto_mask);
19         /*
20          * Make sure the mask is visible before we set
21          * the overload count. That is checked to determine
22          * if we should look at the mask. It would be a shame
23          * if we looked at the mask, but the mask was not
24          * updated yet.
25          */
26         wmb();
27         atomic_inc(&rq->rd->rto_count);
28 }
29
30 static inline void rt_clear_overload(struct rq *rq)
31 {
32         if (!rq->online)
33                 return;
34
35         /* the order here really doesn't matter */
36         atomic_dec(&rq->rd->rto_count);
37         cpu_clear(rq->cpu, rq->rd->rto_mask);
38 }
39
40 static void update_rt_migration(struct rq *rq)
41 {
42         if (rq->rt.rt_nr_migratory && (rq->rt.rt_nr_running > 1)) {
43                 if (!rq->rt.overloaded) {
44                         rt_set_overload(rq);
45                         rq->rt.overloaded = 1;
46                 }
47         } else if (rq->rt.overloaded) {
48                 rt_clear_overload(rq);
49                 rq->rt.overloaded = 0;
50         }
51 }
52 #endif /* CONFIG_SMP */
53
54 static inline struct task_struct *rt_task_of(struct sched_rt_entity *rt_se)
55 {
56         return container_of(rt_se, struct task_struct, rt);
57 }
58
59 static inline int on_rt_rq(struct sched_rt_entity *rt_se)
60 {
61         return !list_empty(&rt_se->run_list);
62 }
63
64 #ifdef CONFIG_RT_GROUP_SCHED
65
66 static inline u64 sched_rt_runtime(struct rt_rq *rt_rq)
67 {
68         if (!rt_rq->tg)
69                 return RUNTIME_INF;
70
71         return rt_rq->rt_runtime;
72 }
73
74 static inline u64 sched_rt_period(struct rt_rq *rt_rq)
75 {
76         return ktime_to_ns(rt_rq->tg->rt_bandwidth.rt_period);
77 }
78
79 #define for_each_leaf_rt_rq(rt_rq, rq) \
80         list_for_each_entry(rt_rq, &rq->leaf_rt_rq_list, leaf_rt_rq_list)
81
82 static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq)
83 {
84         return rt_rq->rq;
85 }
86
87 static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se)
88 {
89         return rt_se->rt_rq;
90 }
91
92 #define for_each_sched_rt_entity(rt_se) \
93         for (; rt_se; rt_se = rt_se->parent)
94
95 static inline struct rt_rq *group_rt_rq(struct sched_rt_entity *rt_se)
96 {
97         return rt_se->my_q;
98 }
99
100 static void enqueue_rt_entity(struct sched_rt_entity *rt_se);
101 static void dequeue_rt_entity(struct sched_rt_entity *rt_se);
102
103 static void sched_rt_rq_enqueue(struct rt_rq *rt_rq)
104 {
105         struct sched_rt_entity *rt_se = rt_rq->rt_se;
106
107         if (rt_se && !on_rt_rq(rt_se) && rt_rq->rt_nr_running) {
108                 struct task_struct *curr = rq_of_rt_rq(rt_rq)->curr;
109
110                 enqueue_rt_entity(rt_se);
111                 if (rt_rq->highest_prio < curr->prio)
112                         resched_task(curr);
113         }
114 }
115
116 static void sched_rt_rq_dequeue(struct rt_rq *rt_rq)
117 {
118         struct sched_rt_entity *rt_se = rt_rq->rt_se;
119
120         if (rt_se && on_rt_rq(rt_se))
121                 dequeue_rt_entity(rt_se);
122 }
123
124 static inline int rt_rq_throttled(struct rt_rq *rt_rq)
125 {
126         return rt_rq->rt_throttled && !rt_rq->rt_nr_boosted;
127 }
128
129 static int rt_se_boosted(struct sched_rt_entity *rt_se)
130 {
131         struct rt_rq *rt_rq = group_rt_rq(rt_se);
132         struct task_struct *p;
133
134         if (rt_rq)
135                 return !!rt_rq->rt_nr_boosted;
136
137         p = rt_task_of(rt_se);
138         return p->prio != p->normal_prio;
139 }
140
141 #ifdef CONFIG_SMP
142 static inline cpumask_t sched_rt_period_mask(void)
143 {
144         return cpu_rq(smp_processor_id())->rd->span;
145 }
146 #else
147 static inline cpumask_t sched_rt_period_mask(void)
148 {
149         return cpu_online_map;
150 }
151 #endif
152
153 static inline
154 struct rt_rq *sched_rt_period_rt_rq(struct rt_bandwidth *rt_b, int cpu)
155 {
156         return container_of(rt_b, struct task_group, rt_bandwidth)->rt_rq[cpu];
157 }
158
159 static inline struct rt_bandwidth *sched_rt_bandwidth(struct rt_rq *rt_rq)
160 {
161         return &rt_rq->tg->rt_bandwidth;
162 }
163
164 #else /* !CONFIG_RT_GROUP_SCHED */
165
166 static inline u64 sched_rt_runtime(struct rt_rq *rt_rq)
167 {
168         return rt_rq->rt_runtime;
169 }
170
171 static inline u64 sched_rt_period(struct rt_rq *rt_rq)
172 {
173         return ktime_to_ns(def_rt_bandwidth.rt_period);
174 }
175
176 #define for_each_leaf_rt_rq(rt_rq, rq) \
177         for (rt_rq = &rq->rt; rt_rq; rt_rq = NULL)
178
179 static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq)
180 {
181         return container_of(rt_rq, struct rq, rt);
182 }
183
184 static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se)
185 {
186         struct task_struct *p = rt_task_of(rt_se);
187         struct rq *rq = task_rq(p);
188
189         return &rq->rt;
190 }
191
192 #define for_each_sched_rt_entity(rt_se) \
193         for (; rt_se; rt_se = NULL)
194
195 static inline struct rt_rq *group_rt_rq(struct sched_rt_entity *rt_se)
196 {
197         return NULL;
198 }
199
200 static inline void sched_rt_rq_enqueue(struct rt_rq *rt_rq)
201 {
202         if (rt_rq->rt_nr_running)
203                 resched_task(rq_of_rt_rq(rt_rq)->curr);
204 }
205
206 static inline void sched_rt_rq_dequeue(struct rt_rq *rt_rq)
207 {
208 }
209
210 static inline int rt_rq_throttled(struct rt_rq *rt_rq)
211 {
212         return rt_rq->rt_throttled;
213 }
214
215 static inline cpumask_t sched_rt_period_mask(void)
216 {
217         return cpu_online_map;
218 }
219
220 static inline
221 struct rt_rq *sched_rt_period_rt_rq(struct rt_bandwidth *rt_b, int cpu)
222 {
223         return &cpu_rq(cpu)->rt;
224 }
225
226 static inline struct rt_bandwidth *sched_rt_bandwidth(struct rt_rq *rt_rq)
227 {
228         return &def_rt_bandwidth;
229 }
230
231 #endif /* CONFIG_RT_GROUP_SCHED */
232
233 #ifdef CONFIG_SMP
234 static int do_balance_runtime(struct rt_rq *rt_rq)
235 {
236         struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
237         struct root_domain *rd = cpu_rq(smp_processor_id())->rd;
238         int i, weight, more = 0;
239         u64 rt_period;
240
241         weight = cpus_weight(rd->span);
242
243         spin_lock(&rt_b->rt_runtime_lock);
244         rt_period = ktime_to_ns(rt_b->rt_period);
245         for_each_cpu_mask_nr(i, rd->span) {
246                 struct rt_rq *iter = sched_rt_period_rt_rq(rt_b, i);
247                 s64 diff;
248
249                 if (iter == rt_rq)
250                         continue;
251
252                 spin_lock(&iter->rt_runtime_lock);
253                 if (iter->rt_runtime == RUNTIME_INF)
254                         goto next;
255
256                 diff = iter->rt_runtime - iter->rt_time;
257                 if (diff > 0) {
258                         diff = div_u64((u64)diff, weight);
259                         if (rt_rq->rt_runtime + diff > rt_period)
260                                 diff = rt_period - rt_rq->rt_runtime;
261                         iter->rt_runtime -= diff;
262                         rt_rq->rt_runtime += diff;
263                         more = 1;
264                         if (rt_rq->rt_runtime == rt_period) {
265                                 spin_unlock(&iter->rt_runtime_lock);
266                                 break;
267                         }
268                 }
269 next:
270                 spin_unlock(&iter->rt_runtime_lock);
271         }
272         spin_unlock(&rt_b->rt_runtime_lock);
273
274         return more;
275 }
276
277 static void __disable_runtime(struct rq *rq)
278 {
279         struct root_domain *rd = rq->rd;
280         struct rt_rq *rt_rq;
281
282         if (unlikely(!scheduler_running))
283                 return;
284
285         for_each_leaf_rt_rq(rt_rq, rq) {
286                 struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
287                 s64 want;
288                 int i;
289
290                 spin_lock(&rt_b->rt_runtime_lock);
291                 spin_lock(&rt_rq->rt_runtime_lock);
292                 if (rt_rq->rt_runtime == RUNTIME_INF ||
293                                 rt_rq->rt_runtime == rt_b->rt_runtime)
294                         goto balanced;
295                 spin_unlock(&rt_rq->rt_runtime_lock);
296
297                 want = rt_b->rt_runtime - rt_rq->rt_runtime;
298
299                 for_each_cpu_mask(i, rd->span) {
300                         struct rt_rq *iter = sched_rt_period_rt_rq(rt_b, i);
301                         s64 diff;
302
303                         if (iter == rt_rq || iter->rt_runtime == RUNTIME_INF)
304                                 continue;
305
306                         spin_lock(&iter->rt_runtime_lock);
307                         if (want > 0) {
308                                 diff = min_t(s64, iter->rt_runtime, want);
309                                 iter->rt_runtime -= diff;
310                                 want -= diff;
311                         } else {
312                                 iter->rt_runtime -= want;
313                                 want -= want;
314                         }
315                         spin_unlock(&iter->rt_runtime_lock);
316
317                         if (!want)
318                                 break;
319                 }
320
321                 spin_lock(&rt_rq->rt_runtime_lock);
322                 BUG_ON(want);
323 balanced:
324                 rt_rq->rt_runtime = RUNTIME_INF;
325                 spin_unlock(&rt_rq->rt_runtime_lock);
326                 spin_unlock(&rt_b->rt_runtime_lock);
327         }
328 }
329
330 static void disable_runtime(struct rq *rq)
331 {
332         unsigned long flags;
333
334         spin_lock_irqsave(&rq->lock, flags);
335         __disable_runtime(rq);
336         spin_unlock_irqrestore(&rq->lock, flags);
337 }
338
339 static void __enable_runtime(struct rq *rq)
340 {
341         struct rt_rq *rt_rq;
342
343         if (unlikely(!scheduler_running))
344                 return;
345
346         for_each_leaf_rt_rq(rt_rq, rq) {
347                 struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
348
349                 spin_lock(&rt_b->rt_runtime_lock);
350                 spin_lock(&rt_rq->rt_runtime_lock);
351                 rt_rq->rt_runtime = rt_b->rt_runtime;
352                 rt_rq->rt_time = 0;
353                 spin_unlock(&rt_rq->rt_runtime_lock);
354                 spin_unlock(&rt_b->rt_runtime_lock);
355         }
356 }
357
358 static void enable_runtime(struct rq *rq)
359 {
360         unsigned long flags;
361
362         spin_lock_irqsave(&rq->lock, flags);
363         __enable_runtime(rq);
364         spin_unlock_irqrestore(&rq->lock, flags);
365 }
366
367 static int balance_runtime(struct rt_rq *rt_rq)
368 {
369         int more = 0;
370
371         if (rt_rq->rt_time > rt_rq->rt_runtime) {
372                 spin_unlock(&rt_rq->rt_runtime_lock);
373                 more = do_balance_runtime(rt_rq);
374                 spin_lock(&rt_rq->rt_runtime_lock);
375         }
376
377         return more;
378 }
379 #else /* !CONFIG_SMP */
380 static inline int balance_runtime(struct rt_rq *rt_rq)
381 {
382         return 0;
383 }
384 #endif /* CONFIG_SMP */
385
386 static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun)
387 {
388         int i, idle = 1;
389         cpumask_t span;
390
391         if (rt_b->rt_runtime == RUNTIME_INF)
392                 return 1;
393
394         span = sched_rt_period_mask();
395         for_each_cpu_mask(i, span) {
396                 int enqueue = 0;
397                 struct rt_rq *rt_rq = sched_rt_period_rt_rq(rt_b, i);
398                 struct rq *rq = rq_of_rt_rq(rt_rq);
399
400                 spin_lock(&rq->lock);
401                 if (rt_rq->rt_time) {
402                         u64 runtime;
403
404                         spin_lock(&rt_rq->rt_runtime_lock);
405                         if (rt_rq->rt_throttled)
406                                 balance_runtime(rt_rq);
407                         runtime = rt_rq->rt_runtime;
408                         rt_rq->rt_time -= min(rt_rq->rt_time, overrun*runtime);
409                         if (rt_rq->rt_throttled && rt_rq->rt_time < runtime) {
410                                 rt_rq->rt_throttled = 0;
411                                 enqueue = 1;
412                         }
413                         if (rt_rq->rt_time || rt_rq->rt_nr_running)
414                                 idle = 0;
415                         spin_unlock(&rt_rq->rt_runtime_lock);
416                 } else if (rt_rq->rt_nr_running)
417                         idle = 0;
418
419                 if (enqueue)
420                         sched_rt_rq_enqueue(rt_rq);
421                 spin_unlock(&rq->lock);
422         }
423
424         return idle;
425 }
426
427 static inline int rt_se_prio(struct sched_rt_entity *rt_se)
428 {
429 #ifdef CONFIG_RT_GROUP_SCHED
430         struct rt_rq *rt_rq = group_rt_rq(rt_se);
431
432         if (rt_rq)
433                 return rt_rq->highest_prio;
434 #endif
435
436         return rt_task_of(rt_se)->prio;
437 }
438
439 static int sched_rt_runtime_exceeded(struct rt_rq *rt_rq)
440 {
441         u64 runtime = sched_rt_runtime(rt_rq);
442
443         if (rt_rq->rt_throttled)
444                 return rt_rq_throttled(rt_rq);
445
446         if (sched_rt_runtime(rt_rq) >= sched_rt_period(rt_rq))
447                 return 0;
448
449         balance_runtime(rt_rq);
450         runtime = sched_rt_runtime(rt_rq);
451         if (runtime == RUNTIME_INF)
452                 return 0;
453
454         if (rt_rq->rt_time > runtime) {
455                 rt_rq->rt_throttled = 1;
456                 if (rt_rq_throttled(rt_rq)) {
457                         sched_rt_rq_dequeue(rt_rq);
458                         return 1;
459                 }
460         }
461
462         return 0;
463 }
464
465 /*
466  * Update the current task's runtime statistics. Skip current tasks that
467  * are not in our scheduling class.
468  */
469 static void update_curr_rt(struct rq *rq)
470 {
471         struct task_struct *curr = rq->curr;
472         struct sched_rt_entity *rt_se = &curr->rt;
473         struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
474         u64 delta_exec;
475
476         if (!task_has_rt_policy(curr))
477                 return;
478
479         delta_exec = rq->clock - curr->se.exec_start;
480         if (unlikely((s64)delta_exec < 0))
481                 delta_exec = 0;
482
483         schedstat_set(curr->se.exec_max, max(curr->se.exec_max, delta_exec));
484
485         curr->se.sum_exec_runtime += delta_exec;
486         curr->se.exec_start = rq->clock;
487         cpuacct_charge(curr, delta_exec);
488
489         for_each_sched_rt_entity(rt_se) {
490                 rt_rq = rt_rq_of_se(rt_se);
491
492                 spin_lock(&rt_rq->rt_runtime_lock);
493                 if (sched_rt_runtime(rt_rq) != RUNTIME_INF) {
494                         rt_rq->rt_time += delta_exec;
495                         if (sched_rt_runtime_exceeded(rt_rq))
496                                 resched_task(curr);
497                 }
498                 spin_unlock(&rt_rq->rt_runtime_lock);
499         }
500 }
501
502 static inline
503 void inc_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
504 {
505         WARN_ON(!rt_prio(rt_se_prio(rt_se)));
506         rt_rq->rt_nr_running++;
507 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
508         if (rt_se_prio(rt_se) < rt_rq->highest_prio) {
509 #ifdef CONFIG_SMP
510                 struct rq *rq = rq_of_rt_rq(rt_rq);
511 #endif
512
513                 rt_rq->highest_prio = rt_se_prio(rt_se);
514 #ifdef CONFIG_SMP
515                 if (rq->online)
516                         cpupri_set(&rq->rd->cpupri, rq->cpu,
517                                    rt_se_prio(rt_se));
518 #endif
519         }
520 #endif
521 #ifdef CONFIG_SMP
522         if (rt_se->nr_cpus_allowed > 1) {
523                 struct rq *rq = rq_of_rt_rq(rt_rq);
524
525                 rq->rt.rt_nr_migratory++;
526         }
527
528         update_rt_migration(rq_of_rt_rq(rt_rq));
529 #endif
530 #ifdef CONFIG_RT_GROUP_SCHED
531         if (rt_se_boosted(rt_se))
532                 rt_rq->rt_nr_boosted++;
533
534         if (rt_rq->tg)
535                 start_rt_bandwidth(&rt_rq->tg->rt_bandwidth);
536 #else
537         start_rt_bandwidth(&def_rt_bandwidth);
538 #endif
539 }
540
541 static inline
542 void dec_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
543 {
544 #ifdef CONFIG_SMP
545         int highest_prio = rt_rq->highest_prio;
546 #endif
547
548         WARN_ON(!rt_prio(rt_se_prio(rt_se)));
549         WARN_ON(!rt_rq->rt_nr_running);
550         rt_rq->rt_nr_running--;
551 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
552         if (rt_rq->rt_nr_running) {
553                 struct rt_prio_array *array;
554
555                 WARN_ON(rt_se_prio(rt_se) < rt_rq->highest_prio);
556                 if (rt_se_prio(rt_se) == rt_rq->highest_prio) {
557                         /* recalculate */
558                         array = &rt_rq->active;
559                         rt_rq->highest_prio =
560                                 sched_find_first_bit(array->bitmap);
561                 } /* otherwise leave rq->highest prio alone */
562         } else
563                 rt_rq->highest_prio = MAX_RT_PRIO;
564 #endif
565 #ifdef CONFIG_SMP
566         if (rt_se->nr_cpus_allowed > 1) {
567                 struct rq *rq = rq_of_rt_rq(rt_rq);
568                 rq->rt.rt_nr_migratory--;
569         }
570
571         if (rt_rq->highest_prio != highest_prio) {
572                 struct rq *rq = rq_of_rt_rq(rt_rq);
573
574                 if (rq->online)
575                         cpupri_set(&rq->rd->cpupri, rq->cpu,
576                                    rt_rq->highest_prio);
577         }
578
579         update_rt_migration(rq_of_rt_rq(rt_rq));
580 #endif /* CONFIG_SMP */
581 #ifdef CONFIG_RT_GROUP_SCHED
582         if (rt_se_boosted(rt_se))
583                 rt_rq->rt_nr_boosted--;
584
585         WARN_ON(!rt_rq->rt_nr_running && rt_rq->rt_nr_boosted);
586 #endif
587 }
588
589 static void __enqueue_rt_entity(struct sched_rt_entity *rt_se)
590 {
591         struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
592         struct rt_prio_array *array = &rt_rq->active;
593         struct rt_rq *group_rq = group_rt_rq(rt_se);
594         struct list_head *queue = array->queue + rt_se_prio(rt_se);
595
596         /*
597          * Don't enqueue the group if its throttled, or when empty.
598          * The latter is a consequence of the former when a child group
599          * get throttled and the current group doesn't have any other
600          * active members.
601          */
602         if (group_rq && (rt_rq_throttled(group_rq) || !group_rq->rt_nr_running))
603                 return;
604
605         list_add_tail(&rt_se->run_list, queue);
606         __set_bit(rt_se_prio(rt_se), array->bitmap);
607
608         inc_rt_tasks(rt_se, rt_rq);
609 }
610
611 static void __dequeue_rt_entity(struct sched_rt_entity *rt_se)
612 {
613         struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
614         struct rt_prio_array *array = &rt_rq->active;
615
616         list_del_init(&rt_se->run_list);
617         if (list_empty(array->queue + rt_se_prio(rt_se)))
618                 __clear_bit(rt_se_prio(rt_se), array->bitmap);
619
620         dec_rt_tasks(rt_se, rt_rq);
621 }
622
623 /*
624  * Because the prio of an upper entry depends on the lower
625  * entries, we must remove entries top - down.
626  */
627 static void dequeue_rt_stack(struct sched_rt_entity *rt_se)
628 {
629         struct sched_rt_entity *back = NULL;
630
631         for_each_sched_rt_entity(rt_se) {
632                 rt_se->back = back;
633                 back = rt_se;
634         }
635
636         for (rt_se = back; rt_se; rt_se = rt_se->back) {
637                 if (on_rt_rq(rt_se))
638                         __dequeue_rt_entity(rt_se);
639         }
640 }
641
642 static void enqueue_rt_entity(struct sched_rt_entity *rt_se)
643 {
644         dequeue_rt_stack(rt_se);
645         for_each_sched_rt_entity(rt_se)
646                 __enqueue_rt_entity(rt_se);
647 }
648
649 static void dequeue_rt_entity(struct sched_rt_entity *rt_se)
650 {
651         dequeue_rt_stack(rt_se);
652
653         for_each_sched_rt_entity(rt_se) {
654                 struct rt_rq *rt_rq = group_rt_rq(rt_se);
655
656                 if (rt_rq && rt_rq->rt_nr_running)
657                         __enqueue_rt_entity(rt_se);
658         }
659 }
660
661 /*
662  * Adding/removing a task to/from a priority array:
663  */
664 static void enqueue_task_rt(struct rq *rq, struct task_struct *p, int wakeup)
665 {
666         struct sched_rt_entity *rt_se = &p->rt;
667
668         if (wakeup)
669                 rt_se->timeout = 0;
670
671         enqueue_rt_entity(rt_se);
672
673         inc_cpu_load(rq, p->se.load.weight);
674 }
675
676 static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int sleep)
677 {
678         struct sched_rt_entity *rt_se = &p->rt;
679
680         update_curr_rt(rq);
681         dequeue_rt_entity(rt_se);
682
683         dec_cpu_load(rq, p->se.load.weight);
684 }
685
686 /*
687  * Put task to the end of the run list without the overhead of dequeue
688  * followed by enqueue.
689  */
690 static void
691 requeue_rt_entity(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se, int head)
692 {
693         if (on_rt_rq(rt_se)) {
694                 struct rt_prio_array *array = &rt_rq->active;
695                 struct list_head *queue = array->queue + rt_se_prio(rt_se);
696
697                 if (head)
698                         list_move(&rt_se->run_list, queue);
699                 else
700                         list_move_tail(&rt_se->run_list, queue);
701         }
702 }
703
704 static void requeue_task_rt(struct rq *rq, struct task_struct *p, int head)
705 {
706         struct sched_rt_entity *rt_se = &p->rt;
707         struct rt_rq *rt_rq;
708
709         for_each_sched_rt_entity(rt_se) {
710                 rt_rq = rt_rq_of_se(rt_se);
711                 requeue_rt_entity(rt_rq, rt_se, head);
712         }
713 }
714
715 static void yield_task_rt(struct rq *rq)
716 {
717         requeue_task_rt(rq, rq->curr, 0);
718 }
719
720 #ifdef CONFIG_SMP
721 static int find_lowest_rq(struct task_struct *task);
722
723 static int select_task_rq_rt(struct task_struct *p, int sync)
724 {
725         struct rq *rq = task_rq(p);
726
727         /*
728          * If the current task is an RT task, then
729          * try to see if we can wake this RT task up on another
730          * runqueue. Otherwise simply start this RT task
731          * on its current runqueue.
732          *
733          * We want to avoid overloading runqueues. Even if
734          * the RT task is of higher priority than the current RT task.
735          * RT tasks behave differently than other tasks. If
736          * one gets preempted, we try to push it off to another queue.
737          * So trying to keep a preempting RT task on the same
738          * cache hot CPU will force the running RT task to
739          * a cold CPU. So we waste all the cache for the lower
740          * RT task in hopes of saving some of a RT task
741          * that is just being woken and probably will have
742          * cold cache anyway.
743          */
744         if (unlikely(rt_task(rq->curr)) &&
745             (p->rt.nr_cpus_allowed > 1)) {
746                 int cpu = find_lowest_rq(p);
747
748                 return (cpu == -1) ? task_cpu(p) : cpu;
749         }
750
751         /*
752          * Otherwise, just let it ride on the affined RQ and the
753          * post-schedule router will push the preempted task away
754          */
755         return task_cpu(p);
756 }
757
758 static void check_preempt_equal_prio(struct rq *rq, struct task_struct *p)
759 {
760         cpumask_t mask;
761
762         if (rq->curr->rt.nr_cpus_allowed == 1)
763                 return;
764
765         if (p->rt.nr_cpus_allowed != 1
766             && cpupri_find(&rq->rd->cpupri, p, &mask))
767                 return;
768
769         if (!cpupri_find(&rq->rd->cpupri, rq->curr, &mask))
770                 return;
771
772         /*
773          * There appears to be other cpus that can accept
774          * current and none to run 'p', so lets reschedule
775          * to try and push current away:
776          */
777         requeue_task_rt(rq, p, 1);
778         resched_task(rq->curr);
779 }
780
781 #endif /* CONFIG_SMP */
782
783 /*
784  * Preempt the current task with a newly woken task if needed:
785  */
786 static void check_preempt_curr_rt(struct rq *rq, struct task_struct *p, int sync)
787 {
788         if (p->prio < rq->curr->prio) {
789                 resched_task(rq->curr);
790                 return;
791         }
792
793 #ifdef CONFIG_SMP
794         /*
795          * If:
796          *
797          * - the newly woken task is of equal priority to the current task
798          * - the newly woken task is non-migratable while current is migratable
799          * - current will be preempted on the next reschedule
800          *
801          * we should check to see if current can readily move to a different
802          * cpu.  If so, we will reschedule to allow the push logic to try
803          * to move current somewhere else, making room for our non-migratable
804          * task.
805          */
806         if (p->prio == rq->curr->prio && !need_resched())
807                 check_preempt_equal_prio(rq, p);
808 #endif
809 }
810
811 static struct sched_rt_entity *pick_next_rt_entity(struct rq *rq,
812                                                    struct rt_rq *rt_rq)
813 {
814         struct rt_prio_array *array = &rt_rq->active;
815         struct sched_rt_entity *next = NULL;
816         struct list_head *queue;
817         int idx;
818
819         idx = sched_find_first_bit(array->bitmap);
820         BUG_ON(idx >= MAX_RT_PRIO);
821
822         queue = array->queue + idx;
823         next = list_entry(queue->next, struct sched_rt_entity, run_list);
824
825         return next;
826 }
827
828 static struct task_struct *pick_next_task_rt(struct rq *rq)
829 {
830         struct sched_rt_entity *rt_se;
831         struct task_struct *p;
832         struct rt_rq *rt_rq;
833
834         rt_rq = &rq->rt;
835
836         if (unlikely(!rt_rq->rt_nr_running))
837                 return NULL;
838
839         if (rt_rq_throttled(rt_rq))
840                 return NULL;
841
842         do {
843                 rt_se = pick_next_rt_entity(rq, rt_rq);
844                 BUG_ON(!rt_se);
845                 rt_rq = group_rt_rq(rt_se);
846         } while (rt_rq);
847
848         p = rt_task_of(rt_se);
849         p->se.exec_start = rq->clock;
850         return p;
851 }
852
853 static void put_prev_task_rt(struct rq *rq, struct task_struct *p)
854 {
855         update_curr_rt(rq);
856         p->se.exec_start = 0;
857 }
858
859 #ifdef CONFIG_SMP
860
861 /* Only try algorithms three times */
862 #define RT_MAX_TRIES 3
863
864 static int double_lock_balance(struct rq *this_rq, struct rq *busiest);
865 static void double_unlock_balance(struct rq *this_rq, struct rq *busiest);
866
867 static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep);
868
869 static int pick_rt_task(struct rq *rq, struct task_struct *p, int cpu)
870 {
871         if (!task_running(rq, p) &&
872             (cpu < 0 || cpu_isset(cpu, p->cpus_allowed)) &&
873             (p->rt.nr_cpus_allowed > 1))
874                 return 1;
875         return 0;
876 }
877
878 /* Return the second highest RT task, NULL otherwise */
879 static struct task_struct *pick_next_highest_task_rt(struct rq *rq, int cpu)
880 {
881         struct task_struct *next = NULL;
882         struct sched_rt_entity *rt_se;
883         struct rt_prio_array *array;
884         struct rt_rq *rt_rq;
885         int idx;
886
887         for_each_leaf_rt_rq(rt_rq, rq) {
888                 array = &rt_rq->active;
889                 idx = sched_find_first_bit(array->bitmap);
890  next_idx:
891                 if (idx >= MAX_RT_PRIO)
892                         continue;
893                 if (next && next->prio < idx)
894                         continue;
895                 list_for_each_entry(rt_se, array->queue + idx, run_list) {
896                         struct task_struct *p = rt_task_of(rt_se);
897                         if (pick_rt_task(rq, p, cpu)) {
898                                 next = p;
899                                 break;
900                         }
901                 }
902                 if (!next) {
903                         idx = find_next_bit(array->bitmap, MAX_RT_PRIO, idx+1);
904                         goto next_idx;
905                 }
906         }
907
908         return next;
909 }
910
911 static DEFINE_PER_CPU(cpumask_t, local_cpu_mask);
912
913 static inline int pick_optimal_cpu(int this_cpu, cpumask_t *mask)
914 {
915         int first;
916
917         /* "this_cpu" is cheaper to preempt than a remote processor */
918         if ((this_cpu != -1) && cpu_isset(this_cpu, *mask))
919                 return this_cpu;
920
921         first = first_cpu(*mask);
922         if (first != NR_CPUS)
923                 return first;
924
925         return -1;
926 }
927
928 static int find_lowest_rq(struct task_struct *task)
929 {
930         struct sched_domain *sd;
931         cpumask_t *lowest_mask = &__get_cpu_var(local_cpu_mask);
932         int this_cpu = smp_processor_id();
933         int cpu      = task_cpu(task);
934
935         if (task->rt.nr_cpus_allowed == 1)
936                 return -1; /* No other targets possible */
937
938         if (!cpupri_find(&task_rq(task)->rd->cpupri, task, lowest_mask))
939                 return -1; /* No targets found */
940
941         /*
942          * Only consider CPUs that are usable for migration.
943          * I guess we might want to change cpupri_find() to ignore those
944          * in the first place.
945          */
946         cpus_and(*lowest_mask, *lowest_mask, cpu_active_map);
947
948         /*
949          * At this point we have built a mask of cpus representing the
950          * lowest priority tasks in the system.  Now we want to elect
951          * the best one based on our affinity and topology.
952          *
953          * We prioritize the last cpu that the task executed on since
954          * it is most likely cache-hot in that location.
955          */
956         if (cpu_isset(cpu, *lowest_mask))
957                 return cpu;
958
959         /*
960          * Otherwise, we consult the sched_domains span maps to figure
961          * out which cpu is logically closest to our hot cache data.
962          */
963         if (this_cpu == cpu)
964                 this_cpu = -1; /* Skip this_cpu opt if the same */
965
966         for_each_domain(cpu, sd) {
967                 if (sd->flags & SD_WAKE_AFFINE) {
968                         cpumask_t domain_mask;
969                         int       best_cpu;
970
971                         cpus_and(domain_mask, sd->span, *lowest_mask);
972
973                         best_cpu = pick_optimal_cpu(this_cpu,
974                                                     &domain_mask);
975                         if (best_cpu != -1)
976                                 return best_cpu;
977                 }
978         }
979
980         /*
981          * And finally, if there were no matches within the domains
982          * just give the caller *something* to work with from the compatible
983          * locations.
984          */
985         return pick_optimal_cpu(this_cpu, lowest_mask);
986 }
987
988 /* Will lock the rq it finds */
989 static struct rq *find_lock_lowest_rq(struct task_struct *task, struct rq *rq)
990 {
991         struct rq *lowest_rq = NULL;
992         int tries;
993         int cpu;
994
995         for (tries = 0; tries < RT_MAX_TRIES; tries++) {
996                 cpu = find_lowest_rq(task);
997
998                 if ((cpu == -1) || (cpu == rq->cpu))
999                         break;
1000
1001                 lowest_rq = cpu_rq(cpu);
1002
1003                 /* if the prio of this runqueue changed, try again */
1004                 if (double_lock_balance(rq, lowest_rq)) {
1005                         /*
1006                          * We had to unlock the run queue. In
1007                          * the mean time, task could have
1008                          * migrated already or had its affinity changed.
1009                          * Also make sure that it wasn't scheduled on its rq.
1010                          */
1011                         if (unlikely(task_rq(task) != rq ||
1012                                      !cpu_isset(lowest_rq->cpu,
1013                                                 task->cpus_allowed) ||
1014                                      task_running(rq, task) ||
1015                                      !task->se.on_rq)) {
1016
1017                                 spin_unlock(&lowest_rq->lock);
1018                                 lowest_rq = NULL;
1019                                 break;
1020                         }
1021                 }
1022
1023                 /* If this rq is still suitable use it. */
1024                 if (lowest_rq->rt.highest_prio > task->prio)
1025                         break;
1026
1027                 /* try again */
1028                 double_unlock_balance(rq, lowest_rq);
1029                 lowest_rq = NULL;
1030         }
1031
1032         return lowest_rq;
1033 }
1034
1035 /*
1036  * If the current CPU has more than one RT task, see if the non
1037  * running task can migrate over to a CPU that is running a task
1038  * of lesser priority.
1039  */
1040 static int push_rt_task(struct rq *rq)
1041 {
1042         struct task_struct *next_task;
1043         struct rq *lowest_rq;
1044         int ret = 0;
1045         int paranoid = RT_MAX_TRIES;
1046
1047         if (!rq->rt.overloaded)
1048                 return 0;
1049
1050         next_task = pick_next_highest_task_rt(rq, -1);
1051         if (!next_task)
1052                 return 0;
1053
1054  retry:
1055         if (unlikely(next_task == rq->curr)) {
1056                 WARN_ON(1);
1057                 return 0;
1058         }
1059
1060         /*
1061          * It's possible that the next_task slipped in of
1062          * higher priority than current. If that's the case
1063          * just reschedule current.
1064          */
1065         if (unlikely(next_task->prio < rq->curr->prio)) {
1066                 resched_task(rq->curr);
1067                 return 0;
1068         }
1069
1070         /* We might release rq lock */
1071         get_task_struct(next_task);
1072
1073         /* find_lock_lowest_rq locks the rq if found */
1074         lowest_rq = find_lock_lowest_rq(next_task, rq);
1075         if (!lowest_rq) {
1076                 struct task_struct *task;
1077                 /*
1078                  * find lock_lowest_rq releases rq->lock
1079                  * so it is possible that next_task has changed.
1080                  * If it has, then try again.
1081                  */
1082                 task = pick_next_highest_task_rt(rq, -1);
1083                 if (unlikely(task != next_task) && task && paranoid--) {
1084                         put_task_struct(next_task);
1085                         next_task = task;
1086                         goto retry;
1087                 }
1088                 goto out;
1089         }
1090
1091         deactivate_task(rq, next_task, 0);
1092         set_task_cpu(next_task, lowest_rq->cpu);
1093         activate_task(lowest_rq, next_task, 0);
1094
1095         resched_task(lowest_rq->curr);
1096
1097         double_unlock_balance(rq, lowest_rq);
1098
1099         ret = 1;
1100 out:
1101         put_task_struct(next_task);
1102
1103         return ret;
1104 }
1105
1106 /*
1107  * TODO: Currently we just use the second highest prio task on
1108  *       the queue, and stop when it can't migrate (or there's
1109  *       no more RT tasks).  There may be a case where a lower
1110  *       priority RT task has a different affinity than the
1111  *       higher RT task. In this case the lower RT task could
1112  *       possibly be able to migrate where as the higher priority
1113  *       RT task could not.  We currently ignore this issue.
1114  *       Enhancements are welcome!
1115  */
1116 static void push_rt_tasks(struct rq *rq)
1117 {
1118         /* push_rt_task will return true if it moved an RT */
1119         while (push_rt_task(rq))
1120                 ;
1121 }
1122
1123 static int pull_rt_task(struct rq *this_rq)
1124 {
1125         int this_cpu = this_rq->cpu, ret = 0, cpu;
1126         struct task_struct *p, *next;
1127         struct rq *src_rq;
1128
1129         if (likely(!rt_overloaded(this_rq)))
1130                 return 0;
1131
1132         next = pick_next_task_rt(this_rq);
1133
1134         for_each_cpu_mask_nr(cpu, this_rq->rd->rto_mask) {
1135                 if (this_cpu == cpu)
1136                         continue;
1137
1138                 src_rq = cpu_rq(cpu);
1139                 /*
1140                  * We can potentially drop this_rq's lock in
1141                  * double_lock_balance, and another CPU could
1142                  * steal our next task - hence we must cause
1143                  * the caller to recalculate the next task
1144                  * in that case:
1145                  */
1146                 if (double_lock_balance(this_rq, src_rq)) {
1147                         struct task_struct *old_next = next;
1148
1149                         next = pick_next_task_rt(this_rq);
1150                         if (next != old_next)
1151                                 ret = 1;
1152                 }
1153
1154                 /*
1155                  * Are there still pullable RT tasks?
1156                  */
1157                 if (src_rq->rt.rt_nr_running <= 1)
1158                         goto skip;
1159
1160                 p = pick_next_highest_task_rt(src_rq, this_cpu);
1161
1162                 /*
1163                  * Do we have an RT task that preempts
1164                  * the to-be-scheduled task?
1165                  */
1166                 if (p && (!next || (p->prio < next->prio))) {
1167                         WARN_ON(p == src_rq->curr);
1168                         WARN_ON(!p->se.on_rq);
1169
1170                         /*
1171                          * There's a chance that p is higher in priority
1172                          * than what's currently running on its cpu.
1173                          * This is just that p is wakeing up and hasn't
1174                          * had a chance to schedule. We only pull
1175                          * p if it is lower in priority than the
1176                          * current task on the run queue or
1177                          * this_rq next task is lower in prio than
1178                          * the current task on that rq.
1179                          */
1180                         if (p->prio < src_rq->curr->prio ||
1181                             (next && next->prio < src_rq->curr->prio))
1182                                 goto skip;
1183
1184                         ret = 1;
1185
1186                         deactivate_task(src_rq, p, 0);
1187                         set_task_cpu(p, this_cpu);
1188                         activate_task(this_rq, p, 0);
1189                         /*
1190                          * We continue with the search, just in
1191                          * case there's an even higher prio task
1192                          * in another runqueue. (low likelyhood
1193                          * but possible)
1194                          *
1195                          * Update next so that we won't pick a task
1196                          * on another cpu with a priority lower (or equal)
1197                          * than the one we just picked.
1198                          */
1199                         next = p;
1200
1201                 }
1202  skip:
1203                 double_unlock_balance(this_rq, src_rq);
1204         }
1205
1206         return ret;
1207 }
1208
1209 static void pre_schedule_rt(struct rq *rq, struct task_struct *prev)
1210 {
1211         /* Try to pull RT tasks here if we lower this rq's prio */
1212         if (unlikely(rt_task(prev)) && rq->rt.highest_prio > prev->prio)
1213                 pull_rt_task(rq);
1214 }
1215
1216 static void post_schedule_rt(struct rq *rq)
1217 {
1218         /*
1219          * If we have more than one rt_task queued, then
1220          * see if we can push the other rt_tasks off to other CPUS.
1221          * Note we may release the rq lock, and since
1222          * the lock was owned by prev, we need to release it
1223          * first via finish_lock_switch and then reaquire it here.
1224          */
1225         if (unlikely(rq->rt.overloaded)) {
1226                 spin_lock_irq(&rq->lock);
1227                 push_rt_tasks(rq);
1228                 spin_unlock_irq(&rq->lock);
1229         }
1230 }
1231
1232 /*
1233  * If we are not running and we are not going to reschedule soon, we should
1234  * try to push tasks away now
1235  */
1236 static void task_wake_up_rt(struct rq *rq, struct task_struct *p)
1237 {
1238         if (!task_running(rq, p) &&
1239             !test_tsk_need_resched(rq->curr) &&
1240             rq->rt.overloaded)
1241                 push_rt_tasks(rq);
1242 }
1243
1244 static unsigned long
1245 load_balance_rt(struct rq *this_rq, int this_cpu, struct rq *busiest,
1246                 unsigned long max_load_move,
1247                 struct sched_domain *sd, enum cpu_idle_type idle,
1248                 int *all_pinned, int *this_best_prio)
1249 {
1250         /* don't touch RT tasks */
1251         return 0;
1252 }
1253
1254 static int
1255 move_one_task_rt(struct rq *this_rq, int this_cpu, struct rq *busiest,
1256                  struct sched_domain *sd, enum cpu_idle_type idle)
1257 {
1258         /* don't touch RT tasks */
1259         return 0;
1260 }
1261
1262 static void set_cpus_allowed_rt(struct task_struct *p,
1263                                 const cpumask_t *new_mask)
1264 {
1265         int weight = cpus_weight(*new_mask);
1266
1267         BUG_ON(!rt_task(p));
1268
1269         /*
1270          * Update the migration status of the RQ if we have an RT task
1271          * which is running AND changing its weight value.
1272          */
1273         if (p->se.on_rq && (weight != p->rt.nr_cpus_allowed)) {
1274                 struct rq *rq = task_rq(p);
1275
1276                 if ((p->rt.nr_cpus_allowed <= 1) && (weight > 1)) {
1277                         rq->rt.rt_nr_migratory++;
1278                 } else if ((p->rt.nr_cpus_allowed > 1) && (weight <= 1)) {
1279                         BUG_ON(!rq->rt.rt_nr_migratory);
1280                         rq->rt.rt_nr_migratory--;
1281                 }
1282
1283                 update_rt_migration(rq);
1284         }
1285
1286         p->cpus_allowed    = *new_mask;
1287         p->rt.nr_cpus_allowed = weight;
1288 }
1289
1290 /* Assumes rq->lock is held */
1291 static void rq_online_rt(struct rq *rq)
1292 {
1293         if (rq->rt.overloaded)
1294                 rt_set_overload(rq);
1295
1296         __enable_runtime(rq);
1297
1298         cpupri_set(&rq->rd->cpupri, rq->cpu, rq->rt.highest_prio);
1299 }
1300
1301 /* Assumes rq->lock is held */
1302 static void rq_offline_rt(struct rq *rq)
1303 {
1304         if (rq->rt.overloaded)
1305                 rt_clear_overload(rq);
1306
1307         __disable_runtime(rq);
1308
1309         cpupri_set(&rq->rd->cpupri, rq->cpu, CPUPRI_INVALID);
1310 }
1311
1312 /*
1313  * When switch from the rt queue, we bring ourselves to a position
1314  * that we might want to pull RT tasks from other runqueues.
1315  */
1316 static void switched_from_rt(struct rq *rq, struct task_struct *p,
1317                            int running)
1318 {
1319         /*
1320          * If there are other RT tasks then we will reschedule
1321          * and the scheduling of the other RT tasks will handle
1322          * the balancing. But if we are the last RT task
1323          * we may need to handle the pulling of RT tasks
1324          * now.
1325          */
1326         if (!rq->rt.rt_nr_running)
1327                 pull_rt_task(rq);
1328 }
1329 #endif /* CONFIG_SMP */
1330
1331 /*
1332  * When switching a task to RT, we may overload the runqueue
1333  * with RT tasks. In this case we try to push them off to
1334  * other runqueues.
1335  */
1336 static void switched_to_rt(struct rq *rq, struct task_struct *p,
1337                            int running)
1338 {
1339         int check_resched = 1;
1340
1341         /*
1342          * If we are already running, then there's nothing
1343          * that needs to be done. But if we are not running
1344          * we may need to preempt the current running task.
1345          * If that current running task is also an RT task
1346          * then see if we can move to another run queue.
1347          */
1348         if (!running) {
1349 #ifdef CONFIG_SMP
1350                 if (rq->rt.overloaded && push_rt_task(rq) &&
1351                     /* Don't resched if we changed runqueues */
1352                     rq != task_rq(p))
1353                         check_resched = 0;
1354 #endif /* CONFIG_SMP */
1355                 if (check_resched && p->prio < rq->curr->prio)
1356                         resched_task(rq->curr);
1357         }
1358 }
1359
1360 /*
1361  * Priority of the task has changed. This may cause
1362  * us to initiate a push or pull.
1363  */
1364 static void prio_changed_rt(struct rq *rq, struct task_struct *p,
1365                             int oldprio, int running)
1366 {
1367         if (running) {
1368 #ifdef CONFIG_SMP
1369                 /*
1370                  * If our priority decreases while running, we
1371                  * may need to pull tasks to this runqueue.
1372                  */
1373                 if (oldprio < p->prio)
1374                         pull_rt_task(rq);
1375                 /*
1376                  * If there's a higher priority task waiting to run
1377                  * then reschedule. Note, the above pull_rt_task
1378                  * can release the rq lock and p could migrate.
1379                  * Only reschedule if p is still on the same runqueue.
1380                  */
1381                 if (p->prio > rq->rt.highest_prio && rq->curr == p)
1382                         resched_task(p);
1383 #else
1384                 /* For UP simply resched on drop of prio */
1385                 if (oldprio < p->prio)
1386                         resched_task(p);
1387 #endif /* CONFIG_SMP */
1388         } else {
1389                 /*
1390                  * This task is not running, but if it is
1391                  * greater than the current running task
1392                  * then reschedule.
1393                  */
1394                 if (p->prio < rq->curr->prio)
1395                         resched_task(rq->curr);
1396         }
1397 }
1398
1399 static void watchdog(struct rq *rq, struct task_struct *p)
1400 {
1401         unsigned long soft, hard;
1402
1403         if (!p->signal)
1404                 return;
1405
1406         soft = p->signal->rlim[RLIMIT_RTTIME].rlim_cur;
1407         hard = p->signal->rlim[RLIMIT_RTTIME].rlim_max;
1408
1409         if (soft != RLIM_INFINITY) {
1410                 unsigned long next;
1411
1412                 p->rt.timeout++;
1413                 next = DIV_ROUND_UP(min(soft, hard), USEC_PER_SEC/HZ);
1414                 if (p->rt.timeout > next)
1415                         p->it_sched_expires = p->se.sum_exec_runtime;
1416         }
1417 }
1418
1419 static void task_tick_rt(struct rq *rq, struct task_struct *p, int queued)
1420 {
1421         update_curr_rt(rq);
1422
1423         watchdog(rq, p);
1424
1425         /*
1426          * RR tasks need a special form of timeslice management.
1427          * FIFO tasks have no timeslices.
1428          */
1429         if (p->policy != SCHED_RR)
1430                 return;
1431
1432         if (--p->rt.time_slice)
1433                 return;
1434
1435         p->rt.time_slice = DEF_TIMESLICE;
1436
1437         /*
1438          * Requeue to the end of queue if we are not the only element
1439          * on the queue:
1440          */
1441         if (p->rt.run_list.prev != p->rt.run_list.next) {
1442                 requeue_task_rt(rq, p, 0);
1443                 set_tsk_need_resched(p);
1444         }
1445 }
1446
1447 static void set_curr_task_rt(struct rq *rq)
1448 {
1449         struct task_struct *p = rq->curr;
1450
1451         p->se.exec_start = rq->clock;
1452 }
1453
1454 static const struct sched_class rt_sched_class = {
1455         .next                   = &fair_sched_class,
1456         .enqueue_task           = enqueue_task_rt,
1457         .dequeue_task           = dequeue_task_rt,
1458         .yield_task             = yield_task_rt,
1459 #ifdef CONFIG_SMP
1460         .select_task_rq         = select_task_rq_rt,
1461 #endif /* CONFIG_SMP */
1462
1463         .check_preempt_curr     = check_preempt_curr_rt,
1464
1465         .pick_next_task         = pick_next_task_rt,
1466         .put_prev_task          = put_prev_task_rt,
1467
1468 #ifdef CONFIG_SMP
1469         .load_balance           = load_balance_rt,
1470         .move_one_task          = move_one_task_rt,
1471         .set_cpus_allowed       = set_cpus_allowed_rt,
1472         .rq_online              = rq_online_rt,
1473         .rq_offline             = rq_offline_rt,
1474         .pre_schedule           = pre_schedule_rt,
1475         .post_schedule          = post_schedule_rt,
1476         .task_wake_up           = task_wake_up_rt,
1477         .switched_from          = switched_from_rt,
1478 #endif
1479
1480         .set_curr_task          = set_curr_task_rt,
1481         .task_tick              = task_tick_rt,
1482
1483         .prio_changed           = prio_changed_rt,
1484         .switched_to            = switched_to_rt,
1485 };
1486
1487 #ifdef CONFIG_SCHED_DEBUG
1488 extern void print_rt_rq(struct seq_file *m, int cpu, struct rt_rq *rt_rq);
1489
1490 static void print_rt_stats(struct seq_file *m, int cpu)
1491 {
1492         struct rt_rq *rt_rq;
1493
1494         rcu_read_lock();
1495         for_each_leaf_rt_rq(rt_rq, cpu_rq(cpu))
1496                 print_rt_rq(m, cpu, rt_rq);
1497         rcu_read_unlock();
1498 }
1499 #endif /* CONFIG_SCHED_DEBUG */