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Commit | Line | Data |
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bb44e5d1 IM |
1 | /* |
2 | * Real-Time Scheduling Class (mapped to the SCHED_FIFO and SCHED_RR | |
3 | * policies) | |
4 | */ | |
5 | ||
4fd29176 SR |
6 | #ifdef CONFIG_SMP |
7 | static cpumask_t rt_overload_mask; | |
8 | static atomic_t rto_count; | |
9 | static inline int rt_overloaded(void) | |
10 | { | |
11 | return atomic_read(&rto_count); | |
12 | } | |
13 | static inline cpumask_t *rt_overload(void) | |
14 | { | |
15 | return &rt_overload_mask; | |
16 | } | |
17 | static inline void rt_set_overload(struct rq *rq) | |
18 | { | |
19 | cpu_set(rq->cpu, rt_overload_mask); | |
20 | /* | |
21 | * Make sure the mask is visible before we set | |
22 | * the overload count. That is checked to determine | |
23 | * if we should look at the mask. It would be a shame | |
24 | * if we looked at the mask, but the mask was not | |
25 | * updated yet. | |
26 | */ | |
27 | wmb(); | |
28 | atomic_inc(&rto_count); | |
29 | } | |
30 | static inline void rt_clear_overload(struct rq *rq) | |
31 | { | |
32 | /* the order here really doesn't matter */ | |
33 | atomic_dec(&rto_count); | |
34 | cpu_clear(rq->cpu, rt_overload_mask); | |
35 | } | |
73fe6aae GH |
36 | |
37 | static void update_rt_migration(struct rq *rq) | |
38 | { | |
39 | if (rq->rt.rt_nr_migratory && (rq->rt.rt_nr_running > 1)) | |
40 | rt_set_overload(rq); | |
41 | else | |
42 | rt_clear_overload(rq); | |
43 | } | |
4fd29176 SR |
44 | #endif /* CONFIG_SMP */ |
45 | ||
bb44e5d1 IM |
46 | /* |
47 | * Update the current task's runtime statistics. Skip current tasks that | |
48 | * are not in our scheduling class. | |
49 | */ | |
a9957449 | 50 | static void update_curr_rt(struct rq *rq) |
bb44e5d1 IM |
51 | { |
52 | struct task_struct *curr = rq->curr; | |
53 | u64 delta_exec; | |
54 | ||
55 | if (!task_has_rt_policy(curr)) | |
56 | return; | |
57 | ||
d281918d | 58 | delta_exec = rq->clock - curr->se.exec_start; |
bb44e5d1 IM |
59 | if (unlikely((s64)delta_exec < 0)) |
60 | delta_exec = 0; | |
6cfb0d5d IM |
61 | |
62 | schedstat_set(curr->se.exec_max, max(curr->se.exec_max, delta_exec)); | |
bb44e5d1 IM |
63 | |
64 | curr->se.sum_exec_runtime += delta_exec; | |
d281918d | 65 | curr->se.exec_start = rq->clock; |
d842de87 | 66 | cpuacct_charge(curr, delta_exec); |
bb44e5d1 IM |
67 | } |
68 | ||
63489e45 SR |
69 | static inline void inc_rt_tasks(struct task_struct *p, struct rq *rq) |
70 | { | |
71 | WARN_ON(!rt_task(p)); | |
72 | rq->rt.rt_nr_running++; | |
764a9d6f SR |
73 | #ifdef CONFIG_SMP |
74 | if (p->prio < rq->rt.highest_prio) | |
75 | rq->rt.highest_prio = p->prio; | |
73fe6aae GH |
76 | if (p->nr_cpus_allowed > 1) |
77 | rq->rt.rt_nr_migratory++; | |
78 | ||
79 | update_rt_migration(rq); | |
764a9d6f | 80 | #endif /* CONFIG_SMP */ |
63489e45 SR |
81 | } |
82 | ||
83 | static inline void dec_rt_tasks(struct task_struct *p, struct rq *rq) | |
84 | { | |
85 | WARN_ON(!rt_task(p)); | |
86 | WARN_ON(!rq->rt.rt_nr_running); | |
87 | rq->rt.rt_nr_running--; | |
764a9d6f SR |
88 | #ifdef CONFIG_SMP |
89 | if (rq->rt.rt_nr_running) { | |
90 | struct rt_prio_array *array; | |
91 | ||
92 | WARN_ON(p->prio < rq->rt.highest_prio); | |
93 | if (p->prio == rq->rt.highest_prio) { | |
94 | /* recalculate */ | |
95 | array = &rq->rt.active; | |
96 | rq->rt.highest_prio = | |
97 | sched_find_first_bit(array->bitmap); | |
98 | } /* otherwise leave rq->highest prio alone */ | |
99 | } else | |
100 | rq->rt.highest_prio = MAX_RT_PRIO; | |
73fe6aae GH |
101 | if (p->nr_cpus_allowed > 1) |
102 | rq->rt.rt_nr_migratory--; | |
103 | ||
104 | update_rt_migration(rq); | |
764a9d6f | 105 | #endif /* CONFIG_SMP */ |
63489e45 SR |
106 | } |
107 | ||
fd390f6a | 108 | static void enqueue_task_rt(struct rq *rq, struct task_struct *p, int wakeup) |
bb44e5d1 IM |
109 | { |
110 | struct rt_prio_array *array = &rq->rt.active; | |
111 | ||
112 | list_add_tail(&p->run_list, array->queue + p->prio); | |
113 | __set_bit(p->prio, array->bitmap); | |
58e2d4ca | 114 | inc_cpu_load(rq, p->se.load.weight); |
63489e45 SR |
115 | |
116 | inc_rt_tasks(p, rq); | |
bb44e5d1 IM |
117 | } |
118 | ||
119 | /* | |
120 | * Adding/removing a task to/from a priority array: | |
121 | */ | |
f02231e5 | 122 | static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int sleep) |
bb44e5d1 IM |
123 | { |
124 | struct rt_prio_array *array = &rq->rt.active; | |
125 | ||
f1e14ef6 | 126 | update_curr_rt(rq); |
bb44e5d1 IM |
127 | |
128 | list_del(&p->run_list); | |
129 | if (list_empty(array->queue + p->prio)) | |
130 | __clear_bit(p->prio, array->bitmap); | |
58e2d4ca | 131 | dec_cpu_load(rq, p->se.load.weight); |
63489e45 SR |
132 | |
133 | dec_rt_tasks(p, rq); | |
bb44e5d1 IM |
134 | } |
135 | ||
136 | /* | |
137 | * Put task to the end of the run list without the overhead of dequeue | |
138 | * followed by enqueue. | |
139 | */ | |
140 | static void requeue_task_rt(struct rq *rq, struct task_struct *p) | |
141 | { | |
142 | struct rt_prio_array *array = &rq->rt.active; | |
143 | ||
144 | list_move_tail(&p->run_list, array->queue + p->prio); | |
145 | } | |
146 | ||
147 | static void | |
4530d7ab | 148 | yield_task_rt(struct rq *rq) |
bb44e5d1 | 149 | { |
4530d7ab | 150 | requeue_task_rt(rq, rq->curr); |
bb44e5d1 IM |
151 | } |
152 | ||
153 | /* | |
154 | * Preempt the current task with a newly woken task if needed: | |
155 | */ | |
156 | static void check_preempt_curr_rt(struct rq *rq, struct task_struct *p) | |
157 | { | |
158 | if (p->prio < rq->curr->prio) | |
159 | resched_task(rq->curr); | |
160 | } | |
161 | ||
fb8d4724 | 162 | static struct task_struct *pick_next_task_rt(struct rq *rq) |
bb44e5d1 IM |
163 | { |
164 | struct rt_prio_array *array = &rq->rt.active; | |
165 | struct task_struct *next; | |
166 | struct list_head *queue; | |
167 | int idx; | |
168 | ||
169 | idx = sched_find_first_bit(array->bitmap); | |
170 | if (idx >= MAX_RT_PRIO) | |
171 | return NULL; | |
172 | ||
173 | queue = array->queue + idx; | |
174 | next = list_entry(queue->next, struct task_struct, run_list); | |
175 | ||
d281918d | 176 | next->se.exec_start = rq->clock; |
bb44e5d1 IM |
177 | |
178 | return next; | |
179 | } | |
180 | ||
31ee529c | 181 | static void put_prev_task_rt(struct rq *rq, struct task_struct *p) |
bb44e5d1 | 182 | { |
f1e14ef6 | 183 | update_curr_rt(rq); |
bb44e5d1 IM |
184 | p->se.exec_start = 0; |
185 | } | |
186 | ||
681f3e68 | 187 | #ifdef CONFIG_SMP |
e8fa1362 SR |
188 | /* Only try algorithms three times */ |
189 | #define RT_MAX_TRIES 3 | |
190 | ||
191 | static int double_lock_balance(struct rq *this_rq, struct rq *busiest); | |
192 | static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep); | |
193 | ||
f65eda4f SR |
194 | static int pick_rt_task(struct rq *rq, struct task_struct *p, int cpu) |
195 | { | |
196 | if (!task_running(rq, p) && | |
73fe6aae GH |
197 | (cpu < 0 || cpu_isset(cpu, p->cpus_allowed)) && |
198 | (p->nr_cpus_allowed > 1)) | |
f65eda4f SR |
199 | return 1; |
200 | return 0; | |
201 | } | |
202 | ||
e8fa1362 | 203 | /* Return the second highest RT task, NULL otherwise */ |
f65eda4f SR |
204 | static struct task_struct *pick_next_highest_task_rt(struct rq *rq, |
205 | int cpu) | |
e8fa1362 SR |
206 | { |
207 | struct rt_prio_array *array = &rq->rt.active; | |
208 | struct task_struct *next; | |
209 | struct list_head *queue; | |
210 | int idx; | |
211 | ||
212 | assert_spin_locked(&rq->lock); | |
213 | ||
214 | if (likely(rq->rt.rt_nr_running < 2)) | |
215 | return NULL; | |
216 | ||
217 | idx = sched_find_first_bit(array->bitmap); | |
218 | if (unlikely(idx >= MAX_RT_PRIO)) { | |
219 | WARN_ON(1); /* rt_nr_running is bad */ | |
220 | return NULL; | |
221 | } | |
222 | ||
223 | queue = array->queue + idx; | |
f65eda4f SR |
224 | BUG_ON(list_empty(queue)); |
225 | ||
e8fa1362 | 226 | next = list_entry(queue->next, struct task_struct, run_list); |
f65eda4f SR |
227 | if (unlikely(pick_rt_task(rq, next, cpu))) |
228 | goto out; | |
e8fa1362 SR |
229 | |
230 | if (queue->next->next != queue) { | |
231 | /* same prio task */ | |
232 | next = list_entry(queue->next->next, struct task_struct, run_list); | |
f65eda4f SR |
233 | if (pick_rt_task(rq, next, cpu)) |
234 | goto out; | |
e8fa1362 SR |
235 | } |
236 | ||
f65eda4f | 237 | retry: |
e8fa1362 SR |
238 | /* slower, but more flexible */ |
239 | idx = find_next_bit(array->bitmap, MAX_RT_PRIO, idx+1); | |
f65eda4f | 240 | if (unlikely(idx >= MAX_RT_PRIO)) |
e8fa1362 | 241 | return NULL; |
e8fa1362 SR |
242 | |
243 | queue = array->queue + idx; | |
f65eda4f SR |
244 | BUG_ON(list_empty(queue)); |
245 | ||
246 | list_for_each_entry(next, queue, run_list) { | |
247 | if (pick_rt_task(rq, next, cpu)) | |
248 | goto out; | |
249 | } | |
250 | ||
251 | goto retry; | |
e8fa1362 | 252 | |
f65eda4f | 253 | out: |
e8fa1362 SR |
254 | return next; |
255 | } | |
256 | ||
257 | static DEFINE_PER_CPU(cpumask_t, local_cpu_mask); | |
258 | ||
259 | /* Will lock the rq it finds */ | |
260 | static struct rq *find_lock_lowest_rq(struct task_struct *task, | |
261 | struct rq *this_rq) | |
262 | { | |
263 | struct rq *lowest_rq = NULL; | |
264 | int cpu; | |
265 | int tries; | |
266 | cpumask_t *cpu_mask = &__get_cpu_var(local_cpu_mask); | |
267 | ||
268 | cpus_and(*cpu_mask, cpu_online_map, task->cpus_allowed); | |
269 | ||
270 | for (tries = 0; tries < RT_MAX_TRIES; tries++) { | |
271 | /* | |
272 | * Scan each rq for the lowest prio. | |
273 | */ | |
274 | for_each_cpu_mask(cpu, *cpu_mask) { | |
275 | struct rq *rq = &per_cpu(runqueues, cpu); | |
276 | ||
277 | if (cpu == this_rq->cpu) | |
278 | continue; | |
279 | ||
280 | /* We look for lowest RT prio or non-rt CPU */ | |
281 | if (rq->rt.highest_prio >= MAX_RT_PRIO) { | |
282 | lowest_rq = rq; | |
283 | break; | |
284 | } | |
285 | ||
286 | /* no locking for now */ | |
287 | if (rq->rt.highest_prio > task->prio && | |
288 | (!lowest_rq || rq->rt.highest_prio > lowest_rq->rt.highest_prio)) { | |
289 | lowest_rq = rq; | |
290 | } | |
291 | } | |
292 | ||
293 | if (!lowest_rq) | |
294 | break; | |
295 | ||
296 | /* if the prio of this runqueue changed, try again */ | |
297 | if (double_lock_balance(this_rq, lowest_rq)) { | |
298 | /* | |
299 | * We had to unlock the run queue. In | |
300 | * the mean time, task could have | |
301 | * migrated already or had its affinity changed. | |
302 | * Also make sure that it wasn't scheduled on its rq. | |
303 | */ | |
304 | if (unlikely(task_rq(task) != this_rq || | |
305 | !cpu_isset(lowest_rq->cpu, task->cpus_allowed) || | |
306 | task_running(this_rq, task) || | |
307 | !task->se.on_rq)) { | |
308 | spin_unlock(&lowest_rq->lock); | |
309 | lowest_rq = NULL; | |
310 | break; | |
311 | } | |
312 | } | |
313 | ||
314 | /* If this rq is still suitable use it. */ | |
315 | if (lowest_rq->rt.highest_prio > task->prio) | |
316 | break; | |
317 | ||
318 | /* try again */ | |
319 | spin_unlock(&lowest_rq->lock); | |
320 | lowest_rq = NULL; | |
321 | } | |
322 | ||
323 | return lowest_rq; | |
324 | } | |
325 | ||
326 | /* | |
327 | * If the current CPU has more than one RT task, see if the non | |
328 | * running task can migrate over to a CPU that is running a task | |
329 | * of lesser priority. | |
330 | */ | |
331 | static int push_rt_task(struct rq *this_rq) | |
332 | { | |
333 | struct task_struct *next_task; | |
334 | struct rq *lowest_rq; | |
335 | int ret = 0; | |
336 | int paranoid = RT_MAX_TRIES; | |
337 | ||
338 | assert_spin_locked(&this_rq->lock); | |
339 | ||
f65eda4f | 340 | next_task = pick_next_highest_task_rt(this_rq, -1); |
e8fa1362 SR |
341 | if (!next_task) |
342 | return 0; | |
343 | ||
344 | retry: | |
f65eda4f SR |
345 | if (unlikely(next_task == this_rq->curr)) { |
346 | WARN_ON(1); | |
e8fa1362 | 347 | return 0; |
f65eda4f | 348 | } |
e8fa1362 SR |
349 | |
350 | /* | |
351 | * It's possible that the next_task slipped in of | |
352 | * higher priority than current. If that's the case | |
353 | * just reschedule current. | |
354 | */ | |
355 | if (unlikely(next_task->prio < this_rq->curr->prio)) { | |
356 | resched_task(this_rq->curr); | |
357 | return 0; | |
358 | } | |
359 | ||
360 | /* We might release this_rq lock */ | |
361 | get_task_struct(next_task); | |
362 | ||
363 | /* find_lock_lowest_rq locks the rq if found */ | |
364 | lowest_rq = find_lock_lowest_rq(next_task, this_rq); | |
365 | if (!lowest_rq) { | |
366 | struct task_struct *task; | |
367 | /* | |
368 | * find lock_lowest_rq releases this_rq->lock | |
369 | * so it is possible that next_task has changed. | |
370 | * If it has, then try again. | |
371 | */ | |
f65eda4f | 372 | task = pick_next_highest_task_rt(this_rq, -1); |
e8fa1362 SR |
373 | if (unlikely(task != next_task) && task && paranoid--) { |
374 | put_task_struct(next_task); | |
375 | next_task = task; | |
376 | goto retry; | |
377 | } | |
378 | goto out; | |
379 | } | |
380 | ||
381 | assert_spin_locked(&lowest_rq->lock); | |
382 | ||
383 | deactivate_task(this_rq, next_task, 0); | |
384 | set_task_cpu(next_task, lowest_rq->cpu); | |
385 | activate_task(lowest_rq, next_task, 0); | |
386 | ||
387 | resched_task(lowest_rq->curr); | |
388 | ||
389 | spin_unlock(&lowest_rq->lock); | |
390 | ||
391 | ret = 1; | |
392 | out: | |
393 | put_task_struct(next_task); | |
394 | ||
395 | return ret; | |
396 | } | |
397 | ||
398 | /* | |
399 | * TODO: Currently we just use the second highest prio task on | |
400 | * the queue, and stop when it can't migrate (or there's | |
401 | * no more RT tasks). There may be a case where a lower | |
402 | * priority RT task has a different affinity than the | |
403 | * higher RT task. In this case the lower RT task could | |
404 | * possibly be able to migrate where as the higher priority | |
405 | * RT task could not. We currently ignore this issue. | |
406 | * Enhancements are welcome! | |
407 | */ | |
408 | static void push_rt_tasks(struct rq *rq) | |
409 | { | |
410 | /* push_rt_task will return true if it moved an RT */ | |
411 | while (push_rt_task(rq)) | |
412 | ; | |
413 | } | |
414 | ||
f65eda4f SR |
415 | static int pull_rt_task(struct rq *this_rq) |
416 | { | |
417 | struct task_struct *next; | |
418 | struct task_struct *p; | |
419 | struct rq *src_rq; | |
420 | cpumask_t *rto_cpumask; | |
421 | int this_cpu = this_rq->cpu; | |
422 | int cpu; | |
423 | int ret = 0; | |
424 | ||
425 | assert_spin_locked(&this_rq->lock); | |
426 | ||
427 | /* | |
428 | * If cpusets are used, and we have overlapping | |
429 | * run queue cpusets, then this algorithm may not catch all. | |
430 | * This is just the price you pay on trying to keep | |
431 | * dirtying caches down on large SMP machines. | |
432 | */ | |
433 | if (likely(!rt_overloaded())) | |
434 | return 0; | |
435 | ||
436 | next = pick_next_task_rt(this_rq); | |
437 | ||
438 | rto_cpumask = rt_overload(); | |
439 | ||
440 | for_each_cpu_mask(cpu, *rto_cpumask) { | |
441 | if (this_cpu == cpu) | |
442 | continue; | |
443 | ||
444 | src_rq = cpu_rq(cpu); | |
445 | if (unlikely(src_rq->rt.rt_nr_running <= 1)) { | |
446 | /* | |
447 | * It is possible that overlapping cpusets | |
448 | * will miss clearing a non overloaded runqueue. | |
449 | * Clear it now. | |
450 | */ | |
451 | if (double_lock_balance(this_rq, src_rq)) { | |
452 | /* unlocked our runqueue lock */ | |
453 | struct task_struct *old_next = next; | |
454 | next = pick_next_task_rt(this_rq); | |
455 | if (next != old_next) | |
456 | ret = 1; | |
457 | } | |
458 | if (likely(src_rq->rt.rt_nr_running <= 1)) | |
459 | /* | |
460 | * Small chance that this_rq->curr changed | |
461 | * but it's really harmless here. | |
462 | */ | |
463 | rt_clear_overload(this_rq); | |
464 | else | |
465 | /* | |
466 | * Heh, the src_rq is now overloaded, since | |
467 | * we already have the src_rq lock, go straight | |
468 | * to pulling tasks from it. | |
469 | */ | |
470 | goto try_pulling; | |
471 | spin_unlock(&src_rq->lock); | |
472 | continue; | |
473 | } | |
474 | ||
475 | /* | |
476 | * We can potentially drop this_rq's lock in | |
477 | * double_lock_balance, and another CPU could | |
478 | * steal our next task - hence we must cause | |
479 | * the caller to recalculate the next task | |
480 | * in that case: | |
481 | */ | |
482 | if (double_lock_balance(this_rq, src_rq)) { | |
483 | struct task_struct *old_next = next; | |
484 | next = pick_next_task_rt(this_rq); | |
485 | if (next != old_next) | |
486 | ret = 1; | |
487 | } | |
488 | ||
489 | /* | |
490 | * Are there still pullable RT tasks? | |
491 | */ | |
492 | if (src_rq->rt.rt_nr_running <= 1) { | |
493 | spin_unlock(&src_rq->lock); | |
494 | continue; | |
495 | } | |
496 | ||
497 | try_pulling: | |
498 | p = pick_next_highest_task_rt(src_rq, this_cpu); | |
499 | ||
500 | /* | |
501 | * Do we have an RT task that preempts | |
502 | * the to-be-scheduled task? | |
503 | */ | |
504 | if (p && (!next || (p->prio < next->prio))) { | |
505 | WARN_ON(p == src_rq->curr); | |
506 | WARN_ON(!p->se.on_rq); | |
507 | ||
508 | /* | |
509 | * There's a chance that p is higher in priority | |
510 | * than what's currently running on its cpu. | |
511 | * This is just that p is wakeing up and hasn't | |
512 | * had a chance to schedule. We only pull | |
513 | * p if it is lower in priority than the | |
514 | * current task on the run queue or | |
515 | * this_rq next task is lower in prio than | |
516 | * the current task on that rq. | |
517 | */ | |
518 | if (p->prio < src_rq->curr->prio || | |
519 | (next && next->prio < src_rq->curr->prio)) | |
520 | goto bail; | |
521 | ||
522 | ret = 1; | |
523 | ||
524 | deactivate_task(src_rq, p, 0); | |
525 | set_task_cpu(p, this_cpu); | |
526 | activate_task(this_rq, p, 0); | |
527 | /* | |
528 | * We continue with the search, just in | |
529 | * case there's an even higher prio task | |
530 | * in another runqueue. (low likelyhood | |
531 | * but possible) | |
532 | */ | |
533 | ||
534 | /* | |
535 | * Update next so that we won't pick a task | |
536 | * on another cpu with a priority lower (or equal) | |
537 | * than the one we just picked. | |
538 | */ | |
539 | next = p; | |
540 | ||
541 | } | |
542 | bail: | |
543 | spin_unlock(&src_rq->lock); | |
544 | } | |
545 | ||
546 | return ret; | |
547 | } | |
548 | ||
549 | static void schedule_balance_rt(struct rq *rq, | |
550 | struct task_struct *prev) | |
551 | { | |
552 | /* Try to pull RT tasks here if we lower this rq's prio */ | |
553 | if (unlikely(rt_task(prev)) && | |
554 | rq->rt.highest_prio > prev->prio) | |
555 | pull_rt_task(rq); | |
556 | } | |
557 | ||
e8fa1362 SR |
558 | static void schedule_tail_balance_rt(struct rq *rq) |
559 | { | |
560 | /* | |
561 | * If we have more than one rt_task queued, then | |
562 | * see if we can push the other rt_tasks off to other CPUS. | |
563 | * Note we may release the rq lock, and since | |
564 | * the lock was owned by prev, we need to release it | |
565 | * first via finish_lock_switch and then reaquire it here. | |
566 | */ | |
567 | if (unlikely(rq->rt.rt_nr_running > 1)) { | |
568 | spin_lock_irq(&rq->lock); | |
569 | push_rt_tasks(rq); | |
570 | spin_unlock_irq(&rq->lock); | |
571 | } | |
572 | } | |
573 | ||
4642dafd SR |
574 | |
575 | static void wakeup_balance_rt(struct rq *rq, struct task_struct *p) | |
576 | { | |
577 | if (unlikely(rt_task(p)) && | |
578 | !task_running(rq, p) && | |
579 | (p->prio >= rq->curr->prio)) | |
580 | push_rt_tasks(rq); | |
581 | } | |
582 | ||
43010659 | 583 | static unsigned long |
bb44e5d1 | 584 | load_balance_rt(struct rq *this_rq, int this_cpu, struct rq *busiest, |
e1d1484f PW |
585 | unsigned long max_load_move, |
586 | struct sched_domain *sd, enum cpu_idle_type idle, | |
587 | int *all_pinned, int *this_best_prio) | |
bb44e5d1 | 588 | { |
c7a1e46a SR |
589 | /* don't touch RT tasks */ |
590 | return 0; | |
e1d1484f PW |
591 | } |
592 | ||
593 | static int | |
594 | move_one_task_rt(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
595 | struct sched_domain *sd, enum cpu_idle_type idle) | |
596 | { | |
c7a1e46a SR |
597 | /* don't touch RT tasks */ |
598 | return 0; | |
bb44e5d1 | 599 | } |
73fe6aae GH |
600 | static void set_cpus_allowed_rt(struct task_struct *p, cpumask_t *new_mask) |
601 | { | |
602 | int weight = cpus_weight(*new_mask); | |
603 | ||
604 | BUG_ON(!rt_task(p)); | |
605 | ||
606 | /* | |
607 | * Update the migration status of the RQ if we have an RT task | |
608 | * which is running AND changing its weight value. | |
609 | */ | |
610 | if (p->se.on_rq && (weight != p->nr_cpus_allowed)) { | |
611 | struct rq *rq = task_rq(p); | |
612 | ||
613 | if ((p->nr_cpus_allowed <= 1) && (weight > 1)) | |
614 | rq->rt.rt_nr_migratory++; | |
615 | else if((p->nr_cpus_allowed > 1) && (weight <= 1)) { | |
616 | BUG_ON(!rq->rt.rt_nr_migratory); | |
617 | rq->rt.rt_nr_migratory--; | |
618 | } | |
619 | ||
620 | update_rt_migration(rq); | |
621 | } | |
622 | ||
623 | p->cpus_allowed = *new_mask; | |
624 | p->nr_cpus_allowed = weight; | |
625 | } | |
e8fa1362 SR |
626 | #else /* CONFIG_SMP */ |
627 | # define schedule_tail_balance_rt(rq) do { } while (0) | |
f65eda4f | 628 | # define schedule_balance_rt(rq, prev) do { } while (0) |
4642dafd | 629 | # define wakeup_balance_rt(rq, p) do { } while (0) |
e8fa1362 | 630 | #endif /* CONFIG_SMP */ |
bb44e5d1 IM |
631 | |
632 | static void task_tick_rt(struct rq *rq, struct task_struct *p) | |
633 | { | |
67e2be02 PZ |
634 | update_curr_rt(rq); |
635 | ||
bb44e5d1 IM |
636 | /* |
637 | * RR tasks need a special form of timeslice management. | |
638 | * FIFO tasks have no timeslices. | |
639 | */ | |
640 | if (p->policy != SCHED_RR) | |
641 | return; | |
642 | ||
643 | if (--p->time_slice) | |
644 | return; | |
645 | ||
a4ec24b4 | 646 | p->time_slice = DEF_TIMESLICE; |
bb44e5d1 | 647 | |
98fbc798 DA |
648 | /* |
649 | * Requeue to the end of queue if we are not the only element | |
650 | * on the queue: | |
651 | */ | |
652 | if (p->run_list.prev != p->run_list.next) { | |
653 | requeue_task_rt(rq, p); | |
654 | set_tsk_need_resched(p); | |
655 | } | |
bb44e5d1 IM |
656 | } |
657 | ||
83b699ed SV |
658 | static void set_curr_task_rt(struct rq *rq) |
659 | { | |
660 | struct task_struct *p = rq->curr; | |
661 | ||
662 | p->se.exec_start = rq->clock; | |
663 | } | |
664 | ||
5522d5d5 IM |
665 | const struct sched_class rt_sched_class = { |
666 | .next = &fair_sched_class, | |
bb44e5d1 IM |
667 | .enqueue_task = enqueue_task_rt, |
668 | .dequeue_task = dequeue_task_rt, | |
669 | .yield_task = yield_task_rt, | |
670 | ||
671 | .check_preempt_curr = check_preempt_curr_rt, | |
672 | ||
673 | .pick_next_task = pick_next_task_rt, | |
674 | .put_prev_task = put_prev_task_rt, | |
675 | ||
681f3e68 | 676 | #ifdef CONFIG_SMP |
bb44e5d1 | 677 | .load_balance = load_balance_rt, |
e1d1484f | 678 | .move_one_task = move_one_task_rt, |
73fe6aae | 679 | .set_cpus_allowed = set_cpus_allowed_rt, |
681f3e68 | 680 | #endif |
bb44e5d1 | 681 | |
83b699ed | 682 | .set_curr_task = set_curr_task_rt, |
bb44e5d1 | 683 | .task_tick = task_tick_rt, |
bb44e5d1 | 684 | }; |