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