Commit | Line | Data |
---|---|---|
bb44e5d1 IM |
1 | /* |
2 | * Real-Time Scheduling Class (mapped to the SCHED_FIFO and SCHED_RR | |
3 | * policies) | |
4 | */ | |
5 | ||
4fd29176 | 6 | #ifdef CONFIG_SMP |
84de4274 | 7 | |
637f5085 | 8 | static inline int rt_overloaded(struct rq *rq) |
4fd29176 | 9 | { |
637f5085 | 10 | return atomic_read(&rq->rd->rto_count); |
4fd29176 | 11 | } |
84de4274 | 12 | |
4fd29176 SR |
13 | static inline void rt_set_overload(struct rq *rq) |
14 | { | |
637f5085 | 15 | cpu_set(rq->cpu, rq->rd->rto_mask); |
4fd29176 SR |
16 | /* |
17 | * Make sure the mask is visible before we set | |
18 | * the overload count. That is checked to determine | |
19 | * if we should look at the mask. It would be a shame | |
20 | * if we looked at the mask, but the mask was not | |
21 | * updated yet. | |
22 | */ | |
23 | wmb(); | |
637f5085 | 24 | atomic_inc(&rq->rd->rto_count); |
4fd29176 | 25 | } |
84de4274 | 26 | |
4fd29176 SR |
27 | static inline void rt_clear_overload(struct rq *rq) |
28 | { | |
29 | /* the order here really doesn't matter */ | |
637f5085 GH |
30 | atomic_dec(&rq->rd->rto_count); |
31 | cpu_clear(rq->cpu, rq->rd->rto_mask); | |
4fd29176 | 32 | } |
73fe6aae GH |
33 | |
34 | static void update_rt_migration(struct rq *rq) | |
35 | { | |
637f5085 | 36 | if (rq->rt.rt_nr_migratory && (rq->rt.rt_nr_running > 1)) { |
cdc8eb98 GH |
37 | if (!rq->rt.overloaded) { |
38 | rt_set_overload(rq); | |
39 | rq->rt.overloaded = 1; | |
40 | } | |
41 | } else if (rq->rt.overloaded) { | |
73fe6aae | 42 | rt_clear_overload(rq); |
637f5085 GH |
43 | rq->rt.overloaded = 0; |
44 | } | |
73fe6aae | 45 | } |
4fd29176 SR |
46 | #endif /* CONFIG_SMP */ |
47 | ||
6f505b16 | 48 | static inline struct task_struct *rt_task_of(struct sched_rt_entity *rt_se) |
fa85ae24 | 49 | { |
6f505b16 PZ |
50 | return container_of(rt_se, struct task_struct, rt); |
51 | } | |
52 | ||
53 | static inline int on_rt_rq(struct sched_rt_entity *rt_se) | |
54 | { | |
55 | return !list_empty(&rt_se->run_list); | |
56 | } | |
57 | ||
58 | #ifdef CONFIG_FAIR_GROUP_SCHED | |
59 | ||
60 | static inline unsigned int sched_rt_ratio(struct rt_rq *rt_rq) | |
61 | { | |
62 | if (!rt_rq->tg) | |
63 | return SCHED_RT_FRAC; | |
64 | ||
65 | return rt_rq->tg->rt_ratio; | |
66 | } | |
67 | ||
68 | #define for_each_leaf_rt_rq(rt_rq, rq) \ | |
69 | list_for_each_entry(rt_rq, &rq->leaf_rt_rq_list, leaf_rt_rq_list) | |
70 | ||
71 | static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq) | |
72 | { | |
73 | return rt_rq->rq; | |
74 | } | |
75 | ||
76 | static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se) | |
77 | { | |
78 | return rt_se->rt_rq; | |
79 | } | |
80 | ||
81 | #define for_each_sched_rt_entity(rt_se) \ | |
82 | for (; rt_se; rt_se = rt_se->parent) | |
83 | ||
84 | static inline struct rt_rq *group_rt_rq(struct sched_rt_entity *rt_se) | |
85 | { | |
86 | return rt_se->my_q; | |
87 | } | |
88 | ||
89 | static void enqueue_rt_entity(struct sched_rt_entity *rt_se); | |
90 | static void dequeue_rt_entity(struct sched_rt_entity *rt_se); | |
91 | ||
92 | static void sched_rt_ratio_enqueue(struct rt_rq *rt_rq) | |
93 | { | |
94 | struct sched_rt_entity *rt_se = rt_rq->rt_se; | |
95 | ||
96 | if (rt_se && !on_rt_rq(rt_se) && rt_rq->rt_nr_running) { | |
1020387f PZ |
97 | struct task_struct *curr = rq_of_rt_rq(rt_rq)->curr; |
98 | ||
6f505b16 | 99 | enqueue_rt_entity(rt_se); |
1020387f PZ |
100 | if (rt_rq->highest_prio < curr->prio) |
101 | resched_task(curr); | |
6f505b16 PZ |
102 | } |
103 | } | |
104 | ||
105 | static void sched_rt_ratio_dequeue(struct rt_rq *rt_rq) | |
106 | { | |
107 | struct sched_rt_entity *rt_se = rt_rq->rt_se; | |
108 | ||
109 | if (rt_se && on_rt_rq(rt_se)) | |
110 | dequeue_rt_entity(rt_se); | |
111 | } | |
112 | ||
113 | #else | |
114 | ||
115 | static inline unsigned int sched_rt_ratio(struct rt_rq *rt_rq) | |
116 | { | |
117 | return sysctl_sched_rt_ratio; | |
118 | } | |
119 | ||
120 | #define for_each_leaf_rt_rq(rt_rq, rq) \ | |
121 | for (rt_rq = &rq->rt; rt_rq; rt_rq = NULL) | |
122 | ||
123 | static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq) | |
124 | { | |
125 | return container_of(rt_rq, struct rq, rt); | |
126 | } | |
127 | ||
128 | static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se) | |
129 | { | |
130 | struct task_struct *p = rt_task_of(rt_se); | |
131 | struct rq *rq = task_rq(p); | |
132 | ||
133 | return &rq->rt; | |
134 | } | |
135 | ||
136 | #define for_each_sched_rt_entity(rt_se) \ | |
137 | for (; rt_se; rt_se = NULL) | |
138 | ||
139 | static inline struct rt_rq *group_rt_rq(struct sched_rt_entity *rt_se) | |
140 | { | |
141 | return NULL; | |
142 | } | |
143 | ||
144 | static inline void sched_rt_ratio_enqueue(struct rt_rq *rt_rq) | |
145 | { | |
146 | } | |
147 | ||
148 | static inline void sched_rt_ratio_dequeue(struct rt_rq *rt_rq) | |
149 | { | |
150 | } | |
151 | ||
152 | #endif | |
153 | ||
154 | static inline int rt_se_prio(struct sched_rt_entity *rt_se) | |
155 | { | |
156 | #ifdef CONFIG_FAIR_GROUP_SCHED | |
157 | struct rt_rq *rt_rq = group_rt_rq(rt_se); | |
158 | ||
159 | if (rt_rq) | |
160 | return rt_rq->highest_prio; | |
161 | #endif | |
162 | ||
163 | return rt_task_of(rt_se)->prio; | |
164 | } | |
165 | ||
166 | static int sched_rt_ratio_exceeded(struct rt_rq *rt_rq) | |
167 | { | |
168 | unsigned int rt_ratio = sched_rt_ratio(rt_rq); | |
fa85ae24 PZ |
169 | u64 period, ratio; |
170 | ||
6f505b16 | 171 | if (rt_ratio == SCHED_RT_FRAC) |
fa85ae24 PZ |
172 | return 0; |
173 | ||
174 | if (rt_rq->rt_throttled) | |
175 | return 1; | |
176 | ||
177 | period = (u64)sysctl_sched_rt_period * NSEC_PER_MSEC; | |
6f505b16 | 178 | ratio = (period * rt_ratio) >> SCHED_RT_FRAC_SHIFT; |
fa85ae24 PZ |
179 | |
180 | if (rt_rq->rt_time > ratio) { | |
48d5e258 PZ |
181 | struct rq *rq = rq_of_rt_rq(rt_rq); |
182 | ||
183 | rq->rt_throttled = 1; | |
6f505b16 | 184 | rt_rq->rt_throttled = 1; |
48d5e258 | 185 | |
6f505b16 | 186 | sched_rt_ratio_dequeue(rt_rq); |
fa85ae24 PZ |
187 | return 1; |
188 | } | |
189 | ||
190 | return 0; | |
191 | } | |
192 | ||
193 | static void update_sched_rt_period(struct rq *rq) | |
194 | { | |
6f505b16 PZ |
195 | struct rt_rq *rt_rq; |
196 | u64 period; | |
fa85ae24 | 197 | |
6f505b16 | 198 | while (rq->clock > rq->rt_period_expire) { |
fa85ae24 | 199 | period = (u64)sysctl_sched_rt_period * NSEC_PER_MSEC; |
fa85ae24 | 200 | rq->rt_period_expire += period; |
fa85ae24 | 201 | |
48d5e258 PZ |
202 | for_each_leaf_rt_rq(rt_rq, rq) { |
203 | unsigned long rt_ratio = sched_rt_ratio(rt_rq); | |
204 | u64 ratio = (period * rt_ratio) >> SCHED_RT_FRAC_SHIFT; | |
205 | ||
206 | rt_rq->rt_time -= min(rt_rq->rt_time, ratio); | |
207 | if (rt_rq->rt_throttled) { | |
208 | rt_rq->rt_throttled = 0; | |
209 | sched_rt_ratio_enqueue(rt_rq); | |
210 | } | |
211 | } | |
212 | ||
213 | rq->rt_throttled = 0; | |
fa85ae24 PZ |
214 | } |
215 | } | |
216 | ||
bb44e5d1 IM |
217 | /* |
218 | * Update the current task's runtime statistics. Skip current tasks that | |
219 | * are not in our scheduling class. | |
220 | */ | |
a9957449 | 221 | static void update_curr_rt(struct rq *rq) |
bb44e5d1 IM |
222 | { |
223 | struct task_struct *curr = rq->curr; | |
6f505b16 PZ |
224 | struct sched_rt_entity *rt_se = &curr->rt; |
225 | struct rt_rq *rt_rq = rt_rq_of_se(rt_se); | |
bb44e5d1 IM |
226 | u64 delta_exec; |
227 | ||
228 | if (!task_has_rt_policy(curr)) | |
229 | return; | |
230 | ||
d281918d | 231 | delta_exec = rq->clock - curr->se.exec_start; |
bb44e5d1 IM |
232 | if (unlikely((s64)delta_exec < 0)) |
233 | delta_exec = 0; | |
6cfb0d5d IM |
234 | |
235 | schedstat_set(curr->se.exec_max, max(curr->se.exec_max, delta_exec)); | |
bb44e5d1 IM |
236 | |
237 | curr->se.sum_exec_runtime += delta_exec; | |
d281918d | 238 | curr->se.exec_start = rq->clock; |
d842de87 | 239 | cpuacct_charge(curr, delta_exec); |
fa85ae24 | 240 | |
6f505b16 PZ |
241 | rt_rq->rt_time += delta_exec; |
242 | /* | |
243 | * might make it a tad more accurate: | |
244 | * | |
245 | * update_sched_rt_period(rq); | |
246 | */ | |
247 | if (sched_rt_ratio_exceeded(rt_rq)) | |
fa85ae24 | 248 | resched_task(curr); |
bb44e5d1 IM |
249 | } |
250 | ||
6f505b16 PZ |
251 | static inline |
252 | void inc_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) | |
63489e45 | 253 | { |
6f505b16 PZ |
254 | WARN_ON(!rt_prio(rt_se_prio(rt_se))); |
255 | rt_rq->rt_nr_running++; | |
256 | #if defined CONFIG_SMP || defined CONFIG_FAIR_GROUP_SCHED | |
257 | if (rt_se_prio(rt_se) < rt_rq->highest_prio) | |
258 | rt_rq->highest_prio = rt_se_prio(rt_se); | |
259 | #endif | |
764a9d6f | 260 | #ifdef CONFIG_SMP |
6f505b16 PZ |
261 | if (rt_se->nr_cpus_allowed > 1) { |
262 | struct rq *rq = rq_of_rt_rq(rt_rq); | |
73fe6aae | 263 | rq->rt.rt_nr_migratory++; |
6f505b16 | 264 | } |
73fe6aae | 265 | |
6f505b16 PZ |
266 | update_rt_migration(rq_of_rt_rq(rt_rq)); |
267 | #endif | |
63489e45 SR |
268 | } |
269 | ||
6f505b16 PZ |
270 | static inline |
271 | void dec_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) | |
63489e45 | 272 | { |
6f505b16 PZ |
273 | WARN_ON(!rt_prio(rt_se_prio(rt_se))); |
274 | WARN_ON(!rt_rq->rt_nr_running); | |
275 | rt_rq->rt_nr_running--; | |
276 | #if defined CONFIG_SMP || defined CONFIG_FAIR_GROUP_SCHED | |
277 | if (rt_rq->rt_nr_running) { | |
764a9d6f SR |
278 | struct rt_prio_array *array; |
279 | ||
6f505b16 PZ |
280 | WARN_ON(rt_se_prio(rt_se) < rt_rq->highest_prio); |
281 | if (rt_se_prio(rt_se) == rt_rq->highest_prio) { | |
764a9d6f | 282 | /* recalculate */ |
6f505b16 PZ |
283 | array = &rt_rq->active; |
284 | rt_rq->highest_prio = | |
764a9d6f SR |
285 | sched_find_first_bit(array->bitmap); |
286 | } /* otherwise leave rq->highest prio alone */ | |
287 | } else | |
6f505b16 PZ |
288 | rt_rq->highest_prio = MAX_RT_PRIO; |
289 | #endif | |
290 | #ifdef CONFIG_SMP | |
291 | if (rt_se->nr_cpus_allowed > 1) { | |
292 | struct rq *rq = rq_of_rt_rq(rt_rq); | |
73fe6aae | 293 | rq->rt.rt_nr_migratory--; |
6f505b16 | 294 | } |
73fe6aae | 295 | |
6f505b16 | 296 | update_rt_migration(rq_of_rt_rq(rt_rq)); |
764a9d6f | 297 | #endif /* CONFIG_SMP */ |
63489e45 SR |
298 | } |
299 | ||
6f505b16 | 300 | static void enqueue_rt_entity(struct sched_rt_entity *rt_se) |
bb44e5d1 | 301 | { |
6f505b16 PZ |
302 | struct rt_rq *rt_rq = rt_rq_of_se(rt_se); |
303 | struct rt_prio_array *array = &rt_rq->active; | |
304 | struct rt_rq *group_rq = group_rt_rq(rt_se); | |
bb44e5d1 | 305 | |
6f505b16 PZ |
306 | if (group_rq && group_rq->rt_throttled) |
307 | return; | |
63489e45 | 308 | |
6f505b16 PZ |
309 | list_add_tail(&rt_se->run_list, array->queue + rt_se_prio(rt_se)); |
310 | __set_bit(rt_se_prio(rt_se), array->bitmap); | |
78f2c7db | 311 | |
6f505b16 PZ |
312 | inc_rt_tasks(rt_se, rt_rq); |
313 | } | |
314 | ||
315 | static void dequeue_rt_entity(struct sched_rt_entity *rt_se) | |
316 | { | |
317 | struct rt_rq *rt_rq = rt_rq_of_se(rt_se); | |
318 | struct rt_prio_array *array = &rt_rq->active; | |
319 | ||
320 | list_del_init(&rt_se->run_list); | |
321 | if (list_empty(array->queue + rt_se_prio(rt_se))) | |
322 | __clear_bit(rt_se_prio(rt_se), array->bitmap); | |
323 | ||
324 | dec_rt_tasks(rt_se, rt_rq); | |
325 | } | |
326 | ||
327 | /* | |
328 | * Because the prio of an upper entry depends on the lower | |
329 | * entries, we must remove entries top - down. | |
330 | * | |
331 | * XXX: O(1/2 h^2) because we can only walk up, not down the chain. | |
332 | * doesn't matter much for now, as h=2 for GROUP_SCHED. | |
333 | */ | |
334 | static void dequeue_rt_stack(struct task_struct *p) | |
335 | { | |
336 | struct sched_rt_entity *rt_se, *top_se; | |
337 | ||
338 | /* | |
339 | * dequeue all, top - down. | |
340 | */ | |
341 | do { | |
342 | rt_se = &p->rt; | |
343 | top_se = NULL; | |
344 | for_each_sched_rt_entity(rt_se) { | |
345 | if (on_rt_rq(rt_se)) | |
346 | top_se = rt_se; | |
347 | } | |
348 | if (top_se) | |
349 | dequeue_rt_entity(top_se); | |
350 | } while (top_se); | |
bb44e5d1 IM |
351 | } |
352 | ||
353 | /* | |
354 | * Adding/removing a task to/from a priority array: | |
355 | */ | |
6f505b16 PZ |
356 | static void enqueue_task_rt(struct rq *rq, struct task_struct *p, int wakeup) |
357 | { | |
358 | struct sched_rt_entity *rt_se = &p->rt; | |
359 | ||
360 | if (wakeup) | |
361 | rt_se->timeout = 0; | |
362 | ||
363 | dequeue_rt_stack(p); | |
364 | ||
365 | /* | |
366 | * enqueue everybody, bottom - up. | |
367 | */ | |
368 | for_each_sched_rt_entity(rt_se) | |
369 | enqueue_rt_entity(rt_se); | |
370 | ||
371 | inc_cpu_load(rq, p->se.load.weight); | |
372 | } | |
373 | ||
f02231e5 | 374 | static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int sleep) |
bb44e5d1 | 375 | { |
6f505b16 PZ |
376 | struct sched_rt_entity *rt_se = &p->rt; |
377 | struct rt_rq *rt_rq; | |
bb44e5d1 | 378 | |
f1e14ef6 | 379 | update_curr_rt(rq); |
bb44e5d1 | 380 | |
6f505b16 PZ |
381 | dequeue_rt_stack(p); |
382 | ||
383 | /* | |
384 | * re-enqueue all non-empty rt_rq entities. | |
385 | */ | |
386 | for_each_sched_rt_entity(rt_se) { | |
387 | rt_rq = group_rt_rq(rt_se); | |
388 | if (rt_rq && rt_rq->rt_nr_running) | |
389 | enqueue_rt_entity(rt_se); | |
390 | } | |
63489e45 | 391 | |
6f505b16 | 392 | dec_cpu_load(rq, p->se.load.weight); |
bb44e5d1 IM |
393 | } |
394 | ||
395 | /* | |
396 | * Put task to the end of the run list without the overhead of dequeue | |
397 | * followed by enqueue. | |
398 | */ | |
6f505b16 PZ |
399 | static |
400 | void requeue_rt_entity(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se) | |
401 | { | |
402 | struct rt_prio_array *array = &rt_rq->active; | |
403 | ||
404 | list_move_tail(&rt_se->run_list, array->queue + rt_se_prio(rt_se)); | |
405 | } | |
406 | ||
bb44e5d1 IM |
407 | static void requeue_task_rt(struct rq *rq, struct task_struct *p) |
408 | { | |
6f505b16 PZ |
409 | struct sched_rt_entity *rt_se = &p->rt; |
410 | struct rt_rq *rt_rq; | |
bb44e5d1 | 411 | |
6f505b16 PZ |
412 | for_each_sched_rt_entity(rt_se) { |
413 | rt_rq = rt_rq_of_se(rt_se); | |
414 | requeue_rt_entity(rt_rq, rt_se); | |
415 | } | |
bb44e5d1 IM |
416 | } |
417 | ||
6f505b16 | 418 | static void yield_task_rt(struct rq *rq) |
bb44e5d1 | 419 | { |
4530d7ab | 420 | requeue_task_rt(rq, rq->curr); |
bb44e5d1 IM |
421 | } |
422 | ||
e7693a36 | 423 | #ifdef CONFIG_SMP |
318e0893 GH |
424 | static int find_lowest_rq(struct task_struct *task); |
425 | ||
e7693a36 GH |
426 | static int select_task_rq_rt(struct task_struct *p, int sync) |
427 | { | |
318e0893 GH |
428 | struct rq *rq = task_rq(p); |
429 | ||
430 | /* | |
e1f47d89 SR |
431 | * If the current task is an RT task, then |
432 | * try to see if we can wake this RT task up on another | |
433 | * runqueue. Otherwise simply start this RT task | |
434 | * on its current runqueue. | |
435 | * | |
436 | * We want to avoid overloading runqueues. Even if | |
437 | * the RT task is of higher priority than the current RT task. | |
438 | * RT tasks behave differently than other tasks. If | |
439 | * one gets preempted, we try to push it off to another queue. | |
440 | * So trying to keep a preempting RT task on the same | |
441 | * cache hot CPU will force the running RT task to | |
442 | * a cold CPU. So we waste all the cache for the lower | |
443 | * RT task in hopes of saving some of a RT task | |
444 | * that is just being woken and probably will have | |
445 | * cold cache anyway. | |
318e0893 | 446 | */ |
17b3279b | 447 | if (unlikely(rt_task(rq->curr)) && |
6f505b16 | 448 | (p->rt.nr_cpus_allowed > 1)) { |
318e0893 GH |
449 | int cpu = find_lowest_rq(p); |
450 | ||
451 | return (cpu == -1) ? task_cpu(p) : cpu; | |
452 | } | |
453 | ||
454 | /* | |
455 | * Otherwise, just let it ride on the affined RQ and the | |
456 | * post-schedule router will push the preempted task away | |
457 | */ | |
e7693a36 GH |
458 | return task_cpu(p); |
459 | } | |
460 | #endif /* CONFIG_SMP */ | |
461 | ||
bb44e5d1 IM |
462 | /* |
463 | * Preempt the current task with a newly woken task if needed: | |
464 | */ | |
465 | static void check_preempt_curr_rt(struct rq *rq, struct task_struct *p) | |
466 | { | |
467 | if (p->prio < rq->curr->prio) | |
468 | resched_task(rq->curr); | |
469 | } | |
470 | ||
6f505b16 PZ |
471 | static struct sched_rt_entity *pick_next_rt_entity(struct rq *rq, |
472 | struct rt_rq *rt_rq) | |
bb44e5d1 | 473 | { |
6f505b16 PZ |
474 | struct rt_prio_array *array = &rt_rq->active; |
475 | struct sched_rt_entity *next = NULL; | |
bb44e5d1 IM |
476 | struct list_head *queue; |
477 | int idx; | |
478 | ||
6f505b16 PZ |
479 | if (sched_rt_ratio_exceeded(rt_rq)) |
480 | goto out; | |
fa85ae24 | 481 | |
bb44e5d1 | 482 | idx = sched_find_first_bit(array->bitmap); |
6f505b16 | 483 | BUG_ON(idx >= MAX_RT_PRIO); |
bb44e5d1 IM |
484 | |
485 | queue = array->queue + idx; | |
6f505b16 PZ |
486 | next = list_entry(queue->next, struct sched_rt_entity, run_list); |
487 | out: | |
488 | return next; | |
489 | } | |
bb44e5d1 | 490 | |
6f505b16 PZ |
491 | static struct task_struct *pick_next_task_rt(struct rq *rq) |
492 | { | |
493 | struct sched_rt_entity *rt_se; | |
494 | struct task_struct *p; | |
495 | struct rt_rq *rt_rq; | |
bb44e5d1 | 496 | |
6f505b16 PZ |
497 | retry: |
498 | rt_rq = &rq->rt; | |
499 | ||
500 | if (unlikely(!rt_rq->rt_nr_running)) | |
501 | return NULL; | |
502 | ||
503 | if (sched_rt_ratio_exceeded(rt_rq)) | |
504 | return NULL; | |
505 | ||
506 | do { | |
507 | rt_se = pick_next_rt_entity(rq, rt_rq); | |
508 | if (unlikely(!rt_se)) | |
509 | goto retry; | |
510 | rt_rq = group_rt_rq(rt_se); | |
511 | } while (rt_rq); | |
512 | ||
513 | p = rt_task_of(rt_se); | |
514 | p->se.exec_start = rq->clock; | |
515 | return p; | |
bb44e5d1 IM |
516 | } |
517 | ||
31ee529c | 518 | static void put_prev_task_rt(struct rq *rq, struct task_struct *p) |
bb44e5d1 | 519 | { |
f1e14ef6 | 520 | update_curr_rt(rq); |
bb44e5d1 IM |
521 | p->se.exec_start = 0; |
522 | } | |
523 | ||
681f3e68 | 524 | #ifdef CONFIG_SMP |
6f505b16 | 525 | |
e8fa1362 SR |
526 | /* Only try algorithms three times */ |
527 | #define RT_MAX_TRIES 3 | |
528 | ||
529 | static int double_lock_balance(struct rq *this_rq, struct rq *busiest); | |
530 | static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep); | |
531 | ||
f65eda4f SR |
532 | static int pick_rt_task(struct rq *rq, struct task_struct *p, int cpu) |
533 | { | |
534 | if (!task_running(rq, p) && | |
73fe6aae | 535 | (cpu < 0 || cpu_isset(cpu, p->cpus_allowed)) && |
6f505b16 | 536 | (p->rt.nr_cpus_allowed > 1)) |
f65eda4f SR |
537 | return 1; |
538 | return 0; | |
539 | } | |
540 | ||
e8fa1362 | 541 | /* Return the second highest RT task, NULL otherwise */ |
79064fbf | 542 | static struct task_struct *pick_next_highest_task_rt(struct rq *rq, int cpu) |
e8fa1362 | 543 | { |
6f505b16 PZ |
544 | struct task_struct *next = NULL; |
545 | struct sched_rt_entity *rt_se; | |
546 | struct rt_prio_array *array; | |
547 | struct rt_rq *rt_rq; | |
e8fa1362 SR |
548 | int idx; |
549 | ||
6f505b16 PZ |
550 | for_each_leaf_rt_rq(rt_rq, rq) { |
551 | array = &rt_rq->active; | |
552 | idx = sched_find_first_bit(array->bitmap); | |
553 | next_idx: | |
554 | if (idx >= MAX_RT_PRIO) | |
555 | continue; | |
556 | if (next && next->prio < idx) | |
557 | continue; | |
558 | list_for_each_entry(rt_se, array->queue + idx, run_list) { | |
559 | struct task_struct *p = rt_task_of(rt_se); | |
560 | if (pick_rt_task(rq, p, cpu)) { | |
561 | next = p; | |
562 | break; | |
563 | } | |
564 | } | |
565 | if (!next) { | |
566 | idx = find_next_bit(array->bitmap, MAX_RT_PRIO, idx+1); | |
567 | goto next_idx; | |
568 | } | |
f65eda4f SR |
569 | } |
570 | ||
e8fa1362 SR |
571 | return next; |
572 | } | |
573 | ||
574 | static DEFINE_PER_CPU(cpumask_t, local_cpu_mask); | |
575 | ||
6e1254d2 | 576 | static int find_lowest_cpus(struct task_struct *task, cpumask_t *lowest_mask) |
e8fa1362 | 577 | { |
6e1254d2 | 578 | int lowest_prio = -1; |
610bf056 | 579 | int lowest_cpu = -1; |
06f90dbd | 580 | int count = 0; |
610bf056 | 581 | int cpu; |
e8fa1362 | 582 | |
637f5085 | 583 | cpus_and(*lowest_mask, task_rq(task)->rd->online, task->cpus_allowed); |
e8fa1362 | 584 | |
07b4032c GH |
585 | /* |
586 | * Scan each rq for the lowest prio. | |
587 | */ | |
610bf056 | 588 | for_each_cpu_mask(cpu, *lowest_mask) { |
07b4032c | 589 | struct rq *rq = cpu_rq(cpu); |
e8fa1362 | 590 | |
07b4032c GH |
591 | /* We look for lowest RT prio or non-rt CPU */ |
592 | if (rq->rt.highest_prio >= MAX_RT_PRIO) { | |
610bf056 SR |
593 | /* |
594 | * if we already found a low RT queue | |
595 | * and now we found this non-rt queue | |
596 | * clear the mask and set our bit. | |
597 | * Otherwise just return the queue as is | |
598 | * and the count==1 will cause the algorithm | |
599 | * to use the first bit found. | |
600 | */ | |
601 | if (lowest_cpu != -1) { | |
6e1254d2 | 602 | cpus_clear(*lowest_mask); |
610bf056 SR |
603 | cpu_set(rq->cpu, *lowest_mask); |
604 | } | |
6e1254d2 | 605 | return 1; |
07b4032c GH |
606 | } |
607 | ||
608 | /* no locking for now */ | |
6e1254d2 GH |
609 | if ((rq->rt.highest_prio > task->prio) |
610 | && (rq->rt.highest_prio >= lowest_prio)) { | |
611 | if (rq->rt.highest_prio > lowest_prio) { | |
612 | /* new low - clear old data */ | |
613 | lowest_prio = rq->rt.highest_prio; | |
610bf056 SR |
614 | lowest_cpu = cpu; |
615 | count = 0; | |
6e1254d2 | 616 | } |
06f90dbd | 617 | count++; |
610bf056 SR |
618 | } else |
619 | cpu_clear(cpu, *lowest_mask); | |
620 | } | |
621 | ||
622 | /* | |
623 | * Clear out all the set bits that represent | |
624 | * runqueues that were of higher prio than | |
625 | * the lowest_prio. | |
626 | */ | |
627 | if (lowest_cpu > 0) { | |
628 | /* | |
629 | * Perhaps we could add another cpumask op to | |
630 | * zero out bits. Like cpu_zero_bits(cpumask, nrbits); | |
631 | * Then that could be optimized to use memset and such. | |
632 | */ | |
633 | for_each_cpu_mask(cpu, *lowest_mask) { | |
634 | if (cpu >= lowest_cpu) | |
635 | break; | |
636 | cpu_clear(cpu, *lowest_mask); | |
e8fa1362 | 637 | } |
07b4032c GH |
638 | } |
639 | ||
06f90dbd | 640 | return count; |
6e1254d2 GH |
641 | } |
642 | ||
643 | static inline int pick_optimal_cpu(int this_cpu, cpumask_t *mask) | |
644 | { | |
645 | int first; | |
646 | ||
647 | /* "this_cpu" is cheaper to preempt than a remote processor */ | |
648 | if ((this_cpu != -1) && cpu_isset(this_cpu, *mask)) | |
649 | return this_cpu; | |
650 | ||
651 | first = first_cpu(*mask); | |
652 | if (first != NR_CPUS) | |
653 | return first; | |
654 | ||
655 | return -1; | |
656 | } | |
657 | ||
658 | static int find_lowest_rq(struct task_struct *task) | |
659 | { | |
660 | struct sched_domain *sd; | |
661 | cpumask_t *lowest_mask = &__get_cpu_var(local_cpu_mask); | |
662 | int this_cpu = smp_processor_id(); | |
663 | int cpu = task_cpu(task); | |
06f90dbd GH |
664 | int count = find_lowest_cpus(task, lowest_mask); |
665 | ||
666 | if (!count) | |
667 | return -1; /* No targets found */ | |
6e1254d2 | 668 | |
06f90dbd GH |
669 | /* |
670 | * There is no sense in performing an optimal search if only one | |
671 | * target is found. | |
672 | */ | |
673 | if (count == 1) | |
674 | return first_cpu(*lowest_mask); | |
6e1254d2 GH |
675 | |
676 | /* | |
677 | * At this point we have built a mask of cpus representing the | |
678 | * lowest priority tasks in the system. Now we want to elect | |
679 | * the best one based on our affinity and topology. | |
680 | * | |
681 | * We prioritize the last cpu that the task executed on since | |
682 | * it is most likely cache-hot in that location. | |
683 | */ | |
684 | if (cpu_isset(cpu, *lowest_mask)) | |
685 | return cpu; | |
686 | ||
687 | /* | |
688 | * Otherwise, we consult the sched_domains span maps to figure | |
689 | * out which cpu is logically closest to our hot cache data. | |
690 | */ | |
691 | if (this_cpu == cpu) | |
692 | this_cpu = -1; /* Skip this_cpu opt if the same */ | |
693 | ||
694 | for_each_domain(cpu, sd) { | |
695 | if (sd->flags & SD_WAKE_AFFINE) { | |
696 | cpumask_t domain_mask; | |
697 | int best_cpu; | |
698 | ||
699 | cpus_and(domain_mask, sd->span, *lowest_mask); | |
700 | ||
701 | best_cpu = pick_optimal_cpu(this_cpu, | |
702 | &domain_mask); | |
703 | if (best_cpu != -1) | |
704 | return best_cpu; | |
705 | } | |
706 | } | |
707 | ||
708 | /* | |
709 | * And finally, if there were no matches within the domains | |
710 | * just give the caller *something* to work with from the compatible | |
711 | * locations. | |
712 | */ | |
713 | return pick_optimal_cpu(this_cpu, lowest_mask); | |
07b4032c GH |
714 | } |
715 | ||
716 | /* Will lock the rq it finds */ | |
4df64c0b | 717 | static struct rq *find_lock_lowest_rq(struct task_struct *task, struct rq *rq) |
07b4032c GH |
718 | { |
719 | struct rq *lowest_rq = NULL; | |
07b4032c | 720 | int tries; |
4df64c0b | 721 | int cpu; |
e8fa1362 | 722 | |
07b4032c GH |
723 | for (tries = 0; tries < RT_MAX_TRIES; tries++) { |
724 | cpu = find_lowest_rq(task); | |
725 | ||
2de0b463 | 726 | if ((cpu == -1) || (cpu == rq->cpu)) |
e8fa1362 SR |
727 | break; |
728 | ||
07b4032c GH |
729 | lowest_rq = cpu_rq(cpu); |
730 | ||
e8fa1362 | 731 | /* if the prio of this runqueue changed, try again */ |
07b4032c | 732 | if (double_lock_balance(rq, lowest_rq)) { |
e8fa1362 SR |
733 | /* |
734 | * We had to unlock the run queue. In | |
735 | * the mean time, task could have | |
736 | * migrated already or had its affinity changed. | |
737 | * Also make sure that it wasn't scheduled on its rq. | |
738 | */ | |
07b4032c | 739 | if (unlikely(task_rq(task) != rq || |
4df64c0b IM |
740 | !cpu_isset(lowest_rq->cpu, |
741 | task->cpus_allowed) || | |
07b4032c | 742 | task_running(rq, task) || |
e8fa1362 | 743 | !task->se.on_rq)) { |
4df64c0b | 744 | |
e8fa1362 SR |
745 | spin_unlock(&lowest_rq->lock); |
746 | lowest_rq = NULL; | |
747 | break; | |
748 | } | |
749 | } | |
750 | ||
751 | /* If this rq is still suitable use it. */ | |
752 | if (lowest_rq->rt.highest_prio > task->prio) | |
753 | break; | |
754 | ||
755 | /* try again */ | |
756 | spin_unlock(&lowest_rq->lock); | |
757 | lowest_rq = NULL; | |
758 | } | |
759 | ||
760 | return lowest_rq; | |
761 | } | |
762 | ||
763 | /* | |
764 | * If the current CPU has more than one RT task, see if the non | |
765 | * running task can migrate over to a CPU that is running a task | |
766 | * of lesser priority. | |
767 | */ | |
697f0a48 | 768 | static int push_rt_task(struct rq *rq) |
e8fa1362 SR |
769 | { |
770 | struct task_struct *next_task; | |
771 | struct rq *lowest_rq; | |
772 | int ret = 0; | |
773 | int paranoid = RT_MAX_TRIES; | |
774 | ||
a22d7fc1 GH |
775 | if (!rq->rt.overloaded) |
776 | return 0; | |
777 | ||
697f0a48 | 778 | next_task = pick_next_highest_task_rt(rq, -1); |
e8fa1362 SR |
779 | if (!next_task) |
780 | return 0; | |
781 | ||
782 | retry: | |
697f0a48 | 783 | if (unlikely(next_task == rq->curr)) { |
f65eda4f | 784 | WARN_ON(1); |
e8fa1362 | 785 | return 0; |
f65eda4f | 786 | } |
e8fa1362 SR |
787 | |
788 | /* | |
789 | * It's possible that the next_task slipped in of | |
790 | * higher priority than current. If that's the case | |
791 | * just reschedule current. | |
792 | */ | |
697f0a48 GH |
793 | if (unlikely(next_task->prio < rq->curr->prio)) { |
794 | resched_task(rq->curr); | |
e8fa1362 SR |
795 | return 0; |
796 | } | |
797 | ||
697f0a48 | 798 | /* We might release rq lock */ |
e8fa1362 SR |
799 | get_task_struct(next_task); |
800 | ||
801 | /* find_lock_lowest_rq locks the rq if found */ | |
697f0a48 | 802 | lowest_rq = find_lock_lowest_rq(next_task, rq); |
e8fa1362 SR |
803 | if (!lowest_rq) { |
804 | struct task_struct *task; | |
805 | /* | |
697f0a48 | 806 | * find lock_lowest_rq releases rq->lock |
e8fa1362 SR |
807 | * so it is possible that next_task has changed. |
808 | * If it has, then try again. | |
809 | */ | |
697f0a48 | 810 | task = pick_next_highest_task_rt(rq, -1); |
e8fa1362 SR |
811 | if (unlikely(task != next_task) && task && paranoid--) { |
812 | put_task_struct(next_task); | |
813 | next_task = task; | |
814 | goto retry; | |
815 | } | |
816 | goto out; | |
817 | } | |
818 | ||
697f0a48 | 819 | deactivate_task(rq, next_task, 0); |
e8fa1362 SR |
820 | set_task_cpu(next_task, lowest_rq->cpu); |
821 | activate_task(lowest_rq, next_task, 0); | |
822 | ||
823 | resched_task(lowest_rq->curr); | |
824 | ||
825 | spin_unlock(&lowest_rq->lock); | |
826 | ||
827 | ret = 1; | |
828 | out: | |
829 | put_task_struct(next_task); | |
830 | ||
831 | return ret; | |
832 | } | |
833 | ||
834 | /* | |
835 | * TODO: Currently we just use the second highest prio task on | |
836 | * the queue, and stop when it can't migrate (or there's | |
837 | * no more RT tasks). There may be a case where a lower | |
838 | * priority RT task has a different affinity than the | |
839 | * higher RT task. In this case the lower RT task could | |
840 | * possibly be able to migrate where as the higher priority | |
841 | * RT task could not. We currently ignore this issue. | |
842 | * Enhancements are welcome! | |
843 | */ | |
844 | static void push_rt_tasks(struct rq *rq) | |
845 | { | |
846 | /* push_rt_task will return true if it moved an RT */ | |
847 | while (push_rt_task(rq)) | |
848 | ; | |
849 | } | |
850 | ||
f65eda4f SR |
851 | static int pull_rt_task(struct rq *this_rq) |
852 | { | |
80bf3171 IM |
853 | int this_cpu = this_rq->cpu, ret = 0, cpu; |
854 | struct task_struct *p, *next; | |
f65eda4f | 855 | struct rq *src_rq; |
f65eda4f | 856 | |
637f5085 | 857 | if (likely(!rt_overloaded(this_rq))) |
f65eda4f SR |
858 | return 0; |
859 | ||
860 | next = pick_next_task_rt(this_rq); | |
861 | ||
637f5085 | 862 | for_each_cpu_mask(cpu, this_rq->rd->rto_mask) { |
f65eda4f SR |
863 | if (this_cpu == cpu) |
864 | continue; | |
865 | ||
866 | src_rq = cpu_rq(cpu); | |
f65eda4f SR |
867 | /* |
868 | * We can potentially drop this_rq's lock in | |
869 | * double_lock_balance, and another CPU could | |
870 | * steal our next task - hence we must cause | |
871 | * the caller to recalculate the next task | |
872 | * in that case: | |
873 | */ | |
874 | if (double_lock_balance(this_rq, src_rq)) { | |
875 | struct task_struct *old_next = next; | |
80bf3171 | 876 | |
f65eda4f SR |
877 | next = pick_next_task_rt(this_rq); |
878 | if (next != old_next) | |
879 | ret = 1; | |
880 | } | |
881 | ||
882 | /* | |
883 | * Are there still pullable RT tasks? | |
884 | */ | |
614ee1f6 MG |
885 | if (src_rq->rt.rt_nr_running <= 1) |
886 | goto skip; | |
f65eda4f | 887 | |
f65eda4f SR |
888 | p = pick_next_highest_task_rt(src_rq, this_cpu); |
889 | ||
890 | /* | |
891 | * Do we have an RT task that preempts | |
892 | * the to-be-scheduled task? | |
893 | */ | |
894 | if (p && (!next || (p->prio < next->prio))) { | |
895 | WARN_ON(p == src_rq->curr); | |
896 | WARN_ON(!p->se.on_rq); | |
897 | ||
898 | /* | |
899 | * There's a chance that p is higher in priority | |
900 | * than what's currently running on its cpu. | |
901 | * This is just that p is wakeing up and hasn't | |
902 | * had a chance to schedule. We only pull | |
903 | * p if it is lower in priority than the | |
904 | * current task on the run queue or | |
905 | * this_rq next task is lower in prio than | |
906 | * the current task on that rq. | |
907 | */ | |
908 | if (p->prio < src_rq->curr->prio || | |
909 | (next && next->prio < src_rq->curr->prio)) | |
614ee1f6 | 910 | goto skip; |
f65eda4f SR |
911 | |
912 | ret = 1; | |
913 | ||
914 | deactivate_task(src_rq, p, 0); | |
915 | set_task_cpu(p, this_cpu); | |
916 | activate_task(this_rq, p, 0); | |
917 | /* | |
918 | * We continue with the search, just in | |
919 | * case there's an even higher prio task | |
920 | * in another runqueue. (low likelyhood | |
921 | * but possible) | |
80bf3171 | 922 | * |
f65eda4f SR |
923 | * Update next so that we won't pick a task |
924 | * on another cpu with a priority lower (or equal) | |
925 | * than the one we just picked. | |
926 | */ | |
927 | next = p; | |
928 | ||
929 | } | |
614ee1f6 | 930 | skip: |
f65eda4f SR |
931 | spin_unlock(&src_rq->lock); |
932 | } | |
933 | ||
934 | return ret; | |
935 | } | |
936 | ||
9a897c5a | 937 | static void pre_schedule_rt(struct rq *rq, struct task_struct *prev) |
f65eda4f SR |
938 | { |
939 | /* Try to pull RT tasks here if we lower this rq's prio */ | |
7f51f298 | 940 | if (unlikely(rt_task(prev)) && rq->rt.highest_prio > prev->prio) |
f65eda4f SR |
941 | pull_rt_task(rq); |
942 | } | |
943 | ||
9a897c5a | 944 | static void post_schedule_rt(struct rq *rq) |
e8fa1362 SR |
945 | { |
946 | /* | |
947 | * If we have more than one rt_task queued, then | |
948 | * see if we can push the other rt_tasks off to other CPUS. | |
949 | * Note we may release the rq lock, and since | |
950 | * the lock was owned by prev, we need to release it | |
951 | * first via finish_lock_switch and then reaquire it here. | |
952 | */ | |
a22d7fc1 | 953 | if (unlikely(rq->rt.overloaded)) { |
e8fa1362 SR |
954 | spin_lock_irq(&rq->lock); |
955 | push_rt_tasks(rq); | |
956 | spin_unlock_irq(&rq->lock); | |
957 | } | |
958 | } | |
959 | ||
4642dafd | 960 | |
9a897c5a | 961 | static void task_wake_up_rt(struct rq *rq, struct task_struct *p) |
4642dafd | 962 | { |
9a897c5a | 963 | if (!task_running(rq, p) && |
a22d7fc1 GH |
964 | (p->prio >= rq->rt.highest_prio) && |
965 | rq->rt.overloaded) | |
4642dafd SR |
966 | push_rt_tasks(rq); |
967 | } | |
968 | ||
43010659 | 969 | static unsigned long |
bb44e5d1 | 970 | load_balance_rt(struct rq *this_rq, int this_cpu, struct rq *busiest, |
e1d1484f PW |
971 | unsigned long max_load_move, |
972 | struct sched_domain *sd, enum cpu_idle_type idle, | |
973 | int *all_pinned, int *this_best_prio) | |
bb44e5d1 | 974 | { |
c7a1e46a SR |
975 | /* don't touch RT tasks */ |
976 | return 0; | |
e1d1484f PW |
977 | } |
978 | ||
979 | static int | |
980 | move_one_task_rt(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
981 | struct sched_domain *sd, enum cpu_idle_type idle) | |
982 | { | |
c7a1e46a SR |
983 | /* don't touch RT tasks */ |
984 | return 0; | |
bb44e5d1 | 985 | } |
deeeccd4 | 986 | |
73fe6aae GH |
987 | static void set_cpus_allowed_rt(struct task_struct *p, cpumask_t *new_mask) |
988 | { | |
989 | int weight = cpus_weight(*new_mask); | |
990 | ||
991 | BUG_ON(!rt_task(p)); | |
992 | ||
993 | /* | |
994 | * Update the migration status of the RQ if we have an RT task | |
995 | * which is running AND changing its weight value. | |
996 | */ | |
6f505b16 | 997 | if (p->se.on_rq && (weight != p->rt.nr_cpus_allowed)) { |
73fe6aae GH |
998 | struct rq *rq = task_rq(p); |
999 | ||
6f505b16 | 1000 | if ((p->rt.nr_cpus_allowed <= 1) && (weight > 1)) { |
73fe6aae | 1001 | rq->rt.rt_nr_migratory++; |
6f505b16 | 1002 | } else if ((p->rt.nr_cpus_allowed > 1) && (weight <= 1)) { |
73fe6aae GH |
1003 | BUG_ON(!rq->rt.rt_nr_migratory); |
1004 | rq->rt.rt_nr_migratory--; | |
1005 | } | |
1006 | ||
1007 | update_rt_migration(rq); | |
1008 | } | |
1009 | ||
1010 | p->cpus_allowed = *new_mask; | |
6f505b16 | 1011 | p->rt.nr_cpus_allowed = weight; |
73fe6aae | 1012 | } |
deeeccd4 | 1013 | |
bdd7c81b IM |
1014 | /* Assumes rq->lock is held */ |
1015 | static void join_domain_rt(struct rq *rq) | |
1016 | { | |
1017 | if (rq->rt.overloaded) | |
1018 | rt_set_overload(rq); | |
1019 | } | |
1020 | ||
1021 | /* Assumes rq->lock is held */ | |
1022 | static void leave_domain_rt(struct rq *rq) | |
1023 | { | |
1024 | if (rq->rt.overloaded) | |
1025 | rt_clear_overload(rq); | |
1026 | } | |
cb469845 SR |
1027 | |
1028 | /* | |
1029 | * When switch from the rt queue, we bring ourselves to a position | |
1030 | * that we might want to pull RT tasks from other runqueues. | |
1031 | */ | |
1032 | static void switched_from_rt(struct rq *rq, struct task_struct *p, | |
1033 | int running) | |
1034 | { | |
1035 | /* | |
1036 | * If there are other RT tasks then we will reschedule | |
1037 | * and the scheduling of the other RT tasks will handle | |
1038 | * the balancing. But if we are the last RT task | |
1039 | * we may need to handle the pulling of RT tasks | |
1040 | * now. | |
1041 | */ | |
1042 | if (!rq->rt.rt_nr_running) | |
1043 | pull_rt_task(rq); | |
1044 | } | |
1045 | #endif /* CONFIG_SMP */ | |
1046 | ||
1047 | /* | |
1048 | * When switching a task to RT, we may overload the runqueue | |
1049 | * with RT tasks. In this case we try to push them off to | |
1050 | * other runqueues. | |
1051 | */ | |
1052 | static void switched_to_rt(struct rq *rq, struct task_struct *p, | |
1053 | int running) | |
1054 | { | |
1055 | int check_resched = 1; | |
1056 | ||
1057 | /* | |
1058 | * If we are already running, then there's nothing | |
1059 | * that needs to be done. But if we are not running | |
1060 | * we may need to preempt the current running task. | |
1061 | * If that current running task is also an RT task | |
1062 | * then see if we can move to another run queue. | |
1063 | */ | |
1064 | if (!running) { | |
1065 | #ifdef CONFIG_SMP | |
1066 | if (rq->rt.overloaded && push_rt_task(rq) && | |
1067 | /* Don't resched if we changed runqueues */ | |
1068 | rq != task_rq(p)) | |
1069 | check_resched = 0; | |
1070 | #endif /* CONFIG_SMP */ | |
1071 | if (check_resched && p->prio < rq->curr->prio) | |
1072 | resched_task(rq->curr); | |
1073 | } | |
1074 | } | |
1075 | ||
1076 | /* | |
1077 | * Priority of the task has changed. This may cause | |
1078 | * us to initiate a push or pull. | |
1079 | */ | |
1080 | static void prio_changed_rt(struct rq *rq, struct task_struct *p, | |
1081 | int oldprio, int running) | |
1082 | { | |
1083 | if (running) { | |
1084 | #ifdef CONFIG_SMP | |
1085 | /* | |
1086 | * If our priority decreases while running, we | |
1087 | * may need to pull tasks to this runqueue. | |
1088 | */ | |
1089 | if (oldprio < p->prio) | |
1090 | pull_rt_task(rq); | |
1091 | /* | |
1092 | * If there's a higher priority task waiting to run | |
1093 | * then reschedule. | |
1094 | */ | |
1095 | if (p->prio > rq->rt.highest_prio) | |
1096 | resched_task(p); | |
1097 | #else | |
1098 | /* For UP simply resched on drop of prio */ | |
1099 | if (oldprio < p->prio) | |
1100 | resched_task(p); | |
e8fa1362 | 1101 | #endif /* CONFIG_SMP */ |
cb469845 SR |
1102 | } else { |
1103 | /* | |
1104 | * This task is not running, but if it is | |
1105 | * greater than the current running task | |
1106 | * then reschedule. | |
1107 | */ | |
1108 | if (p->prio < rq->curr->prio) | |
1109 | resched_task(rq->curr); | |
1110 | } | |
1111 | } | |
1112 | ||
78f2c7db PZ |
1113 | static void watchdog(struct rq *rq, struct task_struct *p) |
1114 | { | |
1115 | unsigned long soft, hard; | |
1116 | ||
1117 | if (!p->signal) | |
1118 | return; | |
1119 | ||
1120 | soft = p->signal->rlim[RLIMIT_RTTIME].rlim_cur; | |
1121 | hard = p->signal->rlim[RLIMIT_RTTIME].rlim_max; | |
1122 | ||
1123 | if (soft != RLIM_INFINITY) { | |
1124 | unsigned long next; | |
1125 | ||
1126 | p->rt.timeout++; | |
1127 | next = DIV_ROUND_UP(min(soft, hard), USEC_PER_SEC/HZ); | |
5a52dd50 | 1128 | if (p->rt.timeout > next) |
78f2c7db PZ |
1129 | p->it_sched_expires = p->se.sum_exec_runtime; |
1130 | } | |
1131 | } | |
bb44e5d1 | 1132 | |
8f4d37ec | 1133 | static void task_tick_rt(struct rq *rq, struct task_struct *p, int queued) |
bb44e5d1 | 1134 | { |
67e2be02 PZ |
1135 | update_curr_rt(rq); |
1136 | ||
78f2c7db PZ |
1137 | watchdog(rq, p); |
1138 | ||
bb44e5d1 IM |
1139 | /* |
1140 | * RR tasks need a special form of timeslice management. | |
1141 | * FIFO tasks have no timeslices. | |
1142 | */ | |
1143 | if (p->policy != SCHED_RR) | |
1144 | return; | |
1145 | ||
fa717060 | 1146 | if (--p->rt.time_slice) |
bb44e5d1 IM |
1147 | return; |
1148 | ||
fa717060 | 1149 | p->rt.time_slice = DEF_TIMESLICE; |
bb44e5d1 | 1150 | |
98fbc798 DA |
1151 | /* |
1152 | * Requeue to the end of queue if we are not the only element | |
1153 | * on the queue: | |
1154 | */ | |
fa717060 | 1155 | if (p->rt.run_list.prev != p->rt.run_list.next) { |
98fbc798 DA |
1156 | requeue_task_rt(rq, p); |
1157 | set_tsk_need_resched(p); | |
1158 | } | |
bb44e5d1 IM |
1159 | } |
1160 | ||
83b699ed SV |
1161 | static void set_curr_task_rt(struct rq *rq) |
1162 | { | |
1163 | struct task_struct *p = rq->curr; | |
1164 | ||
1165 | p->se.exec_start = rq->clock; | |
1166 | } | |
1167 | ||
5522d5d5 IM |
1168 | const struct sched_class rt_sched_class = { |
1169 | .next = &fair_sched_class, | |
bb44e5d1 IM |
1170 | .enqueue_task = enqueue_task_rt, |
1171 | .dequeue_task = dequeue_task_rt, | |
1172 | .yield_task = yield_task_rt, | |
e7693a36 GH |
1173 | #ifdef CONFIG_SMP |
1174 | .select_task_rq = select_task_rq_rt, | |
1175 | #endif /* CONFIG_SMP */ | |
bb44e5d1 IM |
1176 | |
1177 | .check_preempt_curr = check_preempt_curr_rt, | |
1178 | ||
1179 | .pick_next_task = pick_next_task_rt, | |
1180 | .put_prev_task = put_prev_task_rt, | |
1181 | ||
681f3e68 | 1182 | #ifdef CONFIG_SMP |
bb44e5d1 | 1183 | .load_balance = load_balance_rt, |
e1d1484f | 1184 | .move_one_task = move_one_task_rt, |
73fe6aae | 1185 | .set_cpus_allowed = set_cpus_allowed_rt, |
bdd7c81b IM |
1186 | .join_domain = join_domain_rt, |
1187 | .leave_domain = leave_domain_rt, | |
9a897c5a SR |
1188 | .pre_schedule = pre_schedule_rt, |
1189 | .post_schedule = post_schedule_rt, | |
1190 | .task_wake_up = task_wake_up_rt, | |
cb469845 | 1191 | .switched_from = switched_from_rt, |
681f3e68 | 1192 | #endif |
bb44e5d1 | 1193 | |
83b699ed | 1194 | .set_curr_task = set_curr_task_rt, |
bb44e5d1 | 1195 | .task_tick = task_tick_rt, |
cb469845 SR |
1196 | |
1197 | .prio_changed = prio_changed_rt, | |
1198 | .switched_to = switched_to_rt, | |
bb44e5d1 | 1199 | }; |