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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 | { | |
1f11eb6a GH |
15 | if (!rq->online) |
16 | return; | |
17 | ||
637f5085 | 18 | cpu_set(rq->cpu, rq->rd->rto_mask); |
4fd29176 SR |
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(); | |
637f5085 | 27 | atomic_inc(&rq->rd->rto_count); |
4fd29176 | 28 | } |
84de4274 | 29 | |
4fd29176 SR |
30 | static inline void rt_clear_overload(struct rq *rq) |
31 | { | |
1f11eb6a GH |
32 | if (!rq->online) |
33 | return; | |
34 | ||
4fd29176 | 35 | /* the order here really doesn't matter */ |
637f5085 GH |
36 | atomic_dec(&rq->rd->rto_count); |
37 | cpu_clear(rq->cpu, rq->rd->rto_mask); | |
4fd29176 | 38 | } |
73fe6aae GH |
39 | |
40 | static void update_rt_migration(struct rq *rq) | |
41 | { | |
637f5085 | 42 | if (rq->rt.rt_nr_migratory && (rq->rt.rt_nr_running > 1)) { |
cdc8eb98 GH |
43 | if (!rq->rt.overloaded) { |
44 | rt_set_overload(rq); | |
45 | rq->rt.overloaded = 1; | |
46 | } | |
47 | } else if (rq->rt.overloaded) { | |
73fe6aae | 48 | rt_clear_overload(rq); |
637f5085 GH |
49 | rq->rt.overloaded = 0; |
50 | } | |
73fe6aae | 51 | } |
4fd29176 SR |
52 | #endif /* CONFIG_SMP */ |
53 | ||
6f505b16 | 54 | static inline struct task_struct *rt_task_of(struct sched_rt_entity *rt_se) |
fa85ae24 | 55 | { |
6f505b16 PZ |
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 | ||
052f1dc7 | 64 | #ifdef CONFIG_RT_GROUP_SCHED |
6f505b16 | 65 | |
9f0c1e56 | 66 | static inline u64 sched_rt_runtime(struct rt_rq *rt_rq) |
6f505b16 PZ |
67 | { |
68 | if (!rt_rq->tg) | |
9f0c1e56 | 69 | return RUNTIME_INF; |
6f505b16 | 70 | |
ac086bc2 PZ |
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); | |
6f505b16 PZ |
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 | ||
9f0c1e56 | 103 | static void sched_rt_rq_enqueue(struct rt_rq *rt_rq) |
6f505b16 PZ |
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) { | |
1020387f PZ |
108 | struct task_struct *curr = rq_of_rt_rq(rt_rq)->curr; |
109 | ||
6f505b16 | 110 | enqueue_rt_entity(rt_se); |
1020387f PZ |
111 | if (rt_rq->highest_prio < curr->prio) |
112 | resched_task(curr); | |
6f505b16 PZ |
113 | } |
114 | } | |
115 | ||
9f0c1e56 | 116 | static void sched_rt_rq_dequeue(struct rt_rq *rt_rq) |
6f505b16 PZ |
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 | ||
23b0fdfc PZ |
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 | ||
d0b27fa7 PZ |
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 | } | |
6f505b16 | 146 | #else |
d0b27fa7 PZ |
147 | static inline cpumask_t sched_rt_period_mask(void) |
148 | { | |
149 | return cpu_online_map; | |
150 | } | |
151 | #endif | |
6f505b16 | 152 | |
d0b27fa7 PZ |
153 | static inline |
154 | struct rt_rq *sched_rt_period_rt_rq(struct rt_bandwidth *rt_b, int cpu) | |
6f505b16 | 155 | { |
d0b27fa7 PZ |
156 | return container_of(rt_b, struct task_group, rt_bandwidth)->rt_rq[cpu]; |
157 | } | |
9f0c1e56 | 158 | |
ac086bc2 PZ |
159 | static inline struct rt_bandwidth *sched_rt_bandwidth(struct rt_rq *rt_rq) |
160 | { | |
161 | return &rt_rq->tg->rt_bandwidth; | |
162 | } | |
163 | ||
55e12e5e | 164 | #else /* !CONFIG_RT_GROUP_SCHED */ |
d0b27fa7 PZ |
165 | |
166 | static inline u64 sched_rt_runtime(struct rt_rq *rt_rq) | |
167 | { | |
ac086bc2 PZ |
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); | |
6f505b16 PZ |
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 | ||
9f0c1e56 | 200 | static inline void sched_rt_rq_enqueue(struct rt_rq *rt_rq) |
6f505b16 PZ |
201 | { |
202 | } | |
203 | ||
9f0c1e56 | 204 | static inline void sched_rt_rq_dequeue(struct rt_rq *rt_rq) |
6f505b16 PZ |
205 | { |
206 | } | |
207 | ||
23b0fdfc PZ |
208 | static inline int rt_rq_throttled(struct rt_rq *rt_rq) |
209 | { | |
210 | return rt_rq->rt_throttled; | |
211 | } | |
d0b27fa7 PZ |
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 | ||
ac086bc2 PZ |
224 | static inline struct rt_bandwidth *sched_rt_bandwidth(struct rt_rq *rt_rq) |
225 | { | |
226 | return &def_rt_bandwidth; | |
227 | } | |
228 | ||
55e12e5e | 229 | #endif /* CONFIG_RT_GROUP_SCHED */ |
d0b27fa7 | 230 | |
ac086bc2 | 231 | #ifdef CONFIG_SMP |
b79f3833 | 232 | static int do_balance_runtime(struct rt_rq *rt_rq) |
ac086bc2 PZ |
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); | |
363ab6f1 | 243 | for_each_cpu_mask_nr(i, rd->span) { |
ac086bc2 PZ |
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); | |
7def2be1 PZ |
251 | if (iter->rt_runtime == RUNTIME_INF) |
252 | goto next; | |
253 | ||
ac086bc2 PZ |
254 | diff = iter->rt_runtime - iter->rt_time; |
255 | if (diff > 0) { | |
58838cf3 | 256 | diff = div_u64((u64)diff, weight); |
ac086bc2 PZ |
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 | } | |
7def2be1 | 267 | next: |
ac086bc2 PZ |
268 | spin_unlock(&iter->rt_runtime_lock); |
269 | } | |
270 | spin_unlock(&rt_b->rt_runtime_lock); | |
271 | ||
272 | return more; | |
273 | } | |
7def2be1 PZ |
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) | |
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 | { | |
7def2be1 PZ |
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 | ||
eff6549b PZ |
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 | } | |
55e12e5e | 377 | #else /* !CONFIG_SMP */ |
eff6549b PZ |
378 | static inline int balance_runtime(struct rt_rq *rt_rq) |
379 | { | |
380 | return 0; | |
381 | } | |
55e12e5e | 382 | #endif /* CONFIG_SMP */ |
ac086bc2 | 383 | |
eff6549b PZ |
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); | |
6c3df255 PZ |
414 | } else if (rt_rq->rt_nr_running) |
415 | idle = 0; | |
eff6549b PZ |
416 | |
417 | if (enqueue) | |
418 | sched_rt_rq_enqueue(rt_rq); | |
419 | spin_unlock(&rq->lock); | |
420 | } | |
421 | ||
422 | return idle; | |
423 | } | |
ac086bc2 | 424 | |
6f505b16 PZ |
425 | static inline int rt_se_prio(struct sched_rt_entity *rt_se) |
426 | { | |
052f1dc7 | 427 | #ifdef CONFIG_RT_GROUP_SCHED |
6f505b16 PZ |
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 | ||
9f0c1e56 | 437 | static int sched_rt_runtime_exceeded(struct rt_rq *rt_rq) |
6f505b16 | 438 | { |
9f0c1e56 | 439 | u64 runtime = sched_rt_runtime(rt_rq); |
fa85ae24 | 440 | |
9f0c1e56 | 441 | if (runtime == RUNTIME_INF) |
fa85ae24 PZ |
442 | return 0; |
443 | ||
444 | if (rt_rq->rt_throttled) | |
23b0fdfc | 445 | return rt_rq_throttled(rt_rq); |
fa85ae24 | 446 | |
ac086bc2 PZ |
447 | if (sched_rt_runtime(rt_rq) >= sched_rt_period(rt_rq)) |
448 | return 0; | |
449 | ||
b79f3833 PZ |
450 | balance_runtime(rt_rq); |
451 | runtime = sched_rt_runtime(rt_rq); | |
452 | if (runtime == RUNTIME_INF) | |
453 | return 0; | |
ac086bc2 | 454 | |
9f0c1e56 | 455 | if (rt_rq->rt_time > runtime) { |
6f505b16 | 456 | rt_rq->rt_throttled = 1; |
23b0fdfc | 457 | if (rt_rq_throttled(rt_rq)) { |
9f0c1e56 | 458 | sched_rt_rq_dequeue(rt_rq); |
23b0fdfc PZ |
459 | return 1; |
460 | } | |
fa85ae24 PZ |
461 | } |
462 | ||
463 | return 0; | |
464 | } | |
465 | ||
bb44e5d1 IM |
466 | /* |
467 | * Update the current task's runtime statistics. Skip current tasks that | |
468 | * are not in our scheduling class. | |
469 | */ | |
a9957449 | 470 | static void update_curr_rt(struct rq *rq) |
bb44e5d1 IM |
471 | { |
472 | struct task_struct *curr = rq->curr; | |
6f505b16 PZ |
473 | struct sched_rt_entity *rt_se = &curr->rt; |
474 | struct rt_rq *rt_rq = rt_rq_of_se(rt_se); | |
bb44e5d1 IM |
475 | u64 delta_exec; |
476 | ||
477 | if (!task_has_rt_policy(curr)) | |
478 | return; | |
479 | ||
d281918d | 480 | delta_exec = rq->clock - curr->se.exec_start; |
bb44e5d1 IM |
481 | if (unlikely((s64)delta_exec < 0)) |
482 | delta_exec = 0; | |
6cfb0d5d IM |
483 | |
484 | schedstat_set(curr->se.exec_max, max(curr->se.exec_max, delta_exec)); | |
bb44e5d1 IM |
485 | |
486 | curr->se.sum_exec_runtime += delta_exec; | |
d281918d | 487 | curr->se.exec_start = rq->clock; |
d842de87 | 488 | cpuacct_charge(curr, delta_exec); |
fa85ae24 | 489 | |
354d60c2 DG |
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 | } | |
bb44e5d1 IM |
499 | } |
500 | ||
6f505b16 PZ |
501 | static inline |
502 | void inc_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) | |
63489e45 | 503 | { |
6f505b16 PZ |
504 | WARN_ON(!rt_prio(rt_se_prio(rt_se))); |
505 | rt_rq->rt_nr_running++; | |
052f1dc7 | 506 | #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED |
6e0534f2 | 507 | if (rt_se_prio(rt_se) < rt_rq->highest_prio) { |
577b4a58 | 508 | #ifdef CONFIG_SMP |
6e0534f2 | 509 | struct rq *rq = rq_of_rt_rq(rt_rq); |
577b4a58 | 510 | #endif |
1f11eb6a | 511 | |
6f505b16 | 512 | rt_rq->highest_prio = rt_se_prio(rt_se); |
1100ac91 | 513 | #ifdef CONFIG_SMP |
1f11eb6a GH |
514 | if (rq->online) |
515 | cpupri_set(&rq->rd->cpupri, rq->cpu, | |
516 | rt_se_prio(rt_se)); | |
1100ac91 | 517 | #endif |
6e0534f2 | 518 | } |
6f505b16 | 519 | #endif |
764a9d6f | 520 | #ifdef CONFIG_SMP |
6f505b16 PZ |
521 | if (rt_se->nr_cpus_allowed > 1) { |
522 | struct rq *rq = rq_of_rt_rq(rt_rq); | |
1100ac91 | 523 | |
73fe6aae | 524 | rq->rt.rt_nr_migratory++; |
6f505b16 | 525 | } |
73fe6aae | 526 | |
6f505b16 PZ |
527 | update_rt_migration(rq_of_rt_rq(rt_rq)); |
528 | #endif | |
052f1dc7 | 529 | #ifdef CONFIG_RT_GROUP_SCHED |
23b0fdfc PZ |
530 | if (rt_se_boosted(rt_se)) |
531 | rt_rq->rt_nr_boosted++; | |
d0b27fa7 PZ |
532 | |
533 | if (rt_rq->tg) | |
534 | start_rt_bandwidth(&rt_rq->tg->rt_bandwidth); | |
535 | #else | |
536 | start_rt_bandwidth(&def_rt_bandwidth); | |
23b0fdfc | 537 | #endif |
63489e45 SR |
538 | } |
539 | ||
6f505b16 PZ |
540 | static inline |
541 | void dec_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) | |
63489e45 | 542 | { |
6e0534f2 GH |
543 | #ifdef CONFIG_SMP |
544 | int highest_prio = rt_rq->highest_prio; | |
545 | #endif | |
546 | ||
6f505b16 PZ |
547 | WARN_ON(!rt_prio(rt_se_prio(rt_se))); |
548 | WARN_ON(!rt_rq->rt_nr_running); | |
549 | rt_rq->rt_nr_running--; | |
052f1dc7 | 550 | #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED |
6f505b16 | 551 | if (rt_rq->rt_nr_running) { |
764a9d6f SR |
552 | struct rt_prio_array *array; |
553 | ||
6f505b16 PZ |
554 | WARN_ON(rt_se_prio(rt_se) < rt_rq->highest_prio); |
555 | if (rt_se_prio(rt_se) == rt_rq->highest_prio) { | |
764a9d6f | 556 | /* recalculate */ |
6f505b16 PZ |
557 | array = &rt_rq->active; |
558 | rt_rq->highest_prio = | |
764a9d6f SR |
559 | sched_find_first_bit(array->bitmap); |
560 | } /* otherwise leave rq->highest prio alone */ | |
561 | } else | |
6f505b16 PZ |
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); | |
73fe6aae | 567 | rq->rt.rt_nr_migratory--; |
6f505b16 | 568 | } |
73fe6aae | 569 | |
6e0534f2 GH |
570 | if (rt_rq->highest_prio != highest_prio) { |
571 | struct rq *rq = rq_of_rt_rq(rt_rq); | |
1f11eb6a GH |
572 | |
573 | if (rq->online) | |
574 | cpupri_set(&rq->rd->cpupri, rq->cpu, | |
575 | rt_rq->highest_prio); | |
6e0534f2 GH |
576 | } |
577 | ||
6f505b16 | 578 | update_rt_migration(rq_of_rt_rq(rt_rq)); |
764a9d6f | 579 | #endif /* CONFIG_SMP */ |
052f1dc7 | 580 | #ifdef CONFIG_RT_GROUP_SCHED |
23b0fdfc PZ |
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 | |
63489e45 SR |
586 | } |
587 | ||
ad2a3f13 | 588 | static void __enqueue_rt_entity(struct sched_rt_entity *rt_se) |
bb44e5d1 | 589 | { |
6f505b16 PZ |
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); | |
20b6331b | 593 | struct list_head *queue = array->queue + rt_se_prio(rt_se); |
bb44e5d1 | 594 | |
ad2a3f13 PZ |
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)) | |
6f505b16 | 602 | return; |
63489e45 | 603 | |
7ebefa8c | 604 | list_add_tail(&rt_se->run_list, queue); |
6f505b16 | 605 | __set_bit(rt_se_prio(rt_se), array->bitmap); |
78f2c7db | 606 | |
6f505b16 PZ |
607 | inc_rt_tasks(rt_se, rt_rq); |
608 | } | |
609 | ||
ad2a3f13 | 610 | static void __dequeue_rt_entity(struct sched_rt_entity *rt_se) |
6f505b16 PZ |
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. | |
6f505b16 | 625 | */ |
ad2a3f13 | 626 | static void dequeue_rt_stack(struct sched_rt_entity *rt_se) |
6f505b16 | 627 | { |
ad2a3f13 | 628 | struct sched_rt_entity *back = NULL; |
6f505b16 | 629 | |
58d6c2d7 PZ |
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)) | |
ad2a3f13 PZ |
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); | |
58d6c2d7 | 657 | } |
bb44e5d1 IM |
658 | } |
659 | ||
660 | /* | |
661 | * Adding/removing a task to/from a priority array: | |
662 | */ | |
6f505b16 PZ |
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 | ||
ad2a3f13 | 670 | enqueue_rt_entity(rt_se); |
c09595f6 PZ |
671 | |
672 | inc_cpu_load(rq, p->se.load.weight); | |
6f505b16 PZ |
673 | } |
674 | ||
f02231e5 | 675 | static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int sleep) |
bb44e5d1 | 676 | { |
6f505b16 | 677 | struct sched_rt_entity *rt_se = &p->rt; |
bb44e5d1 | 678 | |
f1e14ef6 | 679 | update_curr_rt(rq); |
ad2a3f13 | 680 | dequeue_rt_entity(rt_se); |
c09595f6 PZ |
681 | |
682 | dec_cpu_load(rq, p->se.load.weight); | |
bb44e5d1 IM |
683 | } |
684 | ||
685 | /* | |
686 | * Put task to the end of the run list without the overhead of dequeue | |
687 | * followed by enqueue. | |
688 | */ | |
7ebefa8c DA |
689 | static void |
690 | requeue_rt_entity(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se, int head) | |
6f505b16 | 691 | { |
1cdad715 | 692 | if (on_rt_rq(rt_se)) { |
7ebefa8c DA |
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); | |
1cdad715 | 700 | } |
6f505b16 PZ |
701 | } |
702 | ||
7ebefa8c | 703 | static void requeue_task_rt(struct rq *rq, struct task_struct *p, int head) |
bb44e5d1 | 704 | { |
6f505b16 PZ |
705 | struct sched_rt_entity *rt_se = &p->rt; |
706 | struct rt_rq *rt_rq; | |
bb44e5d1 | 707 | |
6f505b16 PZ |
708 | for_each_sched_rt_entity(rt_se) { |
709 | rt_rq = rt_rq_of_se(rt_se); | |
7ebefa8c | 710 | requeue_rt_entity(rt_rq, rt_se, head); |
6f505b16 | 711 | } |
bb44e5d1 IM |
712 | } |
713 | ||
6f505b16 | 714 | static void yield_task_rt(struct rq *rq) |
bb44e5d1 | 715 | { |
7ebefa8c | 716 | requeue_task_rt(rq, rq->curr, 0); |
bb44e5d1 IM |
717 | } |
718 | ||
e7693a36 | 719 | #ifdef CONFIG_SMP |
318e0893 GH |
720 | static int find_lowest_rq(struct task_struct *task); |
721 | ||
e7693a36 GH |
722 | static int select_task_rq_rt(struct task_struct *p, int sync) |
723 | { | |
318e0893 GH |
724 | struct rq *rq = task_rq(p); |
725 | ||
726 | /* | |
e1f47d89 SR |
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. | |
318e0893 | 742 | */ |
17b3279b | 743 | if (unlikely(rt_task(rq->curr)) && |
6f505b16 | 744 | (p->rt.nr_cpus_allowed > 1)) { |
318e0893 GH |
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 | */ | |
e7693a36 GH |
754 | return task_cpu(p); |
755 | } | |
7ebefa8c DA |
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 | ||
e7693a36 GH |
780 | #endif /* CONFIG_SMP */ |
781 | ||
bb44e5d1 IM |
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 | { | |
45c01e82 | 787 | if (p->prio < rq->curr->prio) { |
bb44e5d1 | 788 | resched_task(rq->curr); |
45c01e82 GH |
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 | */ | |
7ebefa8c DA |
805 | if (p->prio == rq->curr->prio && !need_resched()) |
806 | check_preempt_equal_prio(rq, p); | |
45c01e82 | 807 | #endif |
bb44e5d1 IM |
808 | } |
809 | ||
6f505b16 PZ |
810 | static struct sched_rt_entity *pick_next_rt_entity(struct rq *rq, |
811 | struct rt_rq *rt_rq) | |
bb44e5d1 | 812 | { |
6f505b16 PZ |
813 | struct rt_prio_array *array = &rt_rq->active; |
814 | struct sched_rt_entity *next = NULL; | |
bb44e5d1 IM |
815 | struct list_head *queue; |
816 | int idx; | |
817 | ||
818 | idx = sched_find_first_bit(array->bitmap); | |
6f505b16 | 819 | BUG_ON(idx >= MAX_RT_PRIO); |
bb44e5d1 IM |
820 | |
821 | queue = array->queue + idx; | |
6f505b16 | 822 | next = list_entry(queue->next, struct sched_rt_entity, run_list); |
326587b8 | 823 | |
6f505b16 PZ |
824 | return next; |
825 | } | |
bb44e5d1 | 826 | |
6f505b16 PZ |
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; | |
bb44e5d1 | 832 | |
6f505b16 PZ |
833 | rt_rq = &rq->rt; |
834 | ||
835 | if (unlikely(!rt_rq->rt_nr_running)) | |
836 | return NULL; | |
837 | ||
23b0fdfc | 838 | if (rt_rq_throttled(rt_rq)) |
6f505b16 PZ |
839 | return NULL; |
840 | ||
841 | do { | |
842 | rt_se = pick_next_rt_entity(rq, rt_rq); | |
326587b8 | 843 | BUG_ON(!rt_se); |
6f505b16 PZ |
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; | |
bb44e5d1 IM |
850 | } |
851 | ||
31ee529c | 852 | static void put_prev_task_rt(struct rq *rq, struct task_struct *p) |
bb44e5d1 | 853 | { |
f1e14ef6 | 854 | update_curr_rt(rq); |
bb44e5d1 IM |
855 | p->se.exec_start = 0; |
856 | } | |
857 | ||
681f3e68 | 858 | #ifdef CONFIG_SMP |
6f505b16 | 859 | |
e8fa1362 SR |
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); | |
1b12bbc7 PZ |
864 | static void double_unlock_balance(struct rq *this_rq, struct rq *busiest); |
865 | ||
e8fa1362 SR |
866 | static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep); |
867 | ||
f65eda4f SR |
868 | static int pick_rt_task(struct rq *rq, struct task_struct *p, int cpu) |
869 | { | |
870 | if (!task_running(rq, p) && | |
73fe6aae | 871 | (cpu < 0 || cpu_isset(cpu, p->cpus_allowed)) && |
6f505b16 | 872 | (p->rt.nr_cpus_allowed > 1)) |
f65eda4f SR |
873 | return 1; |
874 | return 0; | |
875 | } | |
876 | ||
e8fa1362 | 877 | /* Return the second highest RT task, NULL otherwise */ |
79064fbf | 878 | static struct task_struct *pick_next_highest_task_rt(struct rq *rq, int cpu) |
e8fa1362 | 879 | { |
6f505b16 PZ |
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; | |
e8fa1362 SR |
884 | int idx; |
885 | ||
6f505b16 PZ |
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 | } | |
f65eda4f SR |
905 | } |
906 | ||
e8fa1362 SR |
907 | return next; |
908 | } | |
909 | ||
910 | static DEFINE_PER_CPU(cpumask_t, local_cpu_mask); | |
911 | ||
6e1254d2 GH |
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); | |
06f90dbd | 933 | |
6e0534f2 GH |
934 | if (task->rt.nr_cpus_allowed == 1) |
935 | return -1; /* No other targets possible */ | |
6e1254d2 | 936 | |
6e0534f2 GH |
937 | if (!cpupri_find(&task_rq(task)->rd->cpupri, task, lowest_mask)) |
938 | return -1; /* No targets found */ | |
6e1254d2 | 939 | |
e761b772 MK |
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 | ||
6e1254d2 GH |
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); | |
07b4032c GH |
985 | } |
986 | ||
987 | /* Will lock the rq it finds */ | |
4df64c0b | 988 | static struct rq *find_lock_lowest_rq(struct task_struct *task, struct rq *rq) |
07b4032c GH |
989 | { |
990 | struct rq *lowest_rq = NULL; | |
07b4032c | 991 | int tries; |
4df64c0b | 992 | int cpu; |
e8fa1362 | 993 | |
07b4032c GH |
994 | for (tries = 0; tries < RT_MAX_TRIES; tries++) { |
995 | cpu = find_lowest_rq(task); | |
996 | ||
2de0b463 | 997 | if ((cpu == -1) || (cpu == rq->cpu)) |
e8fa1362 SR |
998 | break; |
999 | ||
07b4032c GH |
1000 | lowest_rq = cpu_rq(cpu); |
1001 | ||
e8fa1362 | 1002 | /* if the prio of this runqueue changed, try again */ |
07b4032c | 1003 | if (double_lock_balance(rq, lowest_rq)) { |
e8fa1362 SR |
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 | */ | |
07b4032c | 1010 | if (unlikely(task_rq(task) != rq || |
4df64c0b IM |
1011 | !cpu_isset(lowest_rq->cpu, |
1012 | task->cpus_allowed) || | |
07b4032c | 1013 | task_running(rq, task) || |
e8fa1362 | 1014 | !task->se.on_rq)) { |
4df64c0b | 1015 | |
e8fa1362 SR |
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 */ | |
1b12bbc7 | 1027 | double_unlock_balance(rq, lowest_rq); |
e8fa1362 SR |
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 | */ | |
697f0a48 | 1039 | static int push_rt_task(struct rq *rq) |
e8fa1362 SR |
1040 | { |
1041 | struct task_struct *next_task; | |
1042 | struct rq *lowest_rq; | |
1043 | int ret = 0; | |
1044 | int paranoid = RT_MAX_TRIES; | |
1045 | ||
a22d7fc1 GH |
1046 | if (!rq->rt.overloaded) |
1047 | return 0; | |
1048 | ||
697f0a48 | 1049 | next_task = pick_next_highest_task_rt(rq, -1); |
e8fa1362 SR |
1050 | if (!next_task) |
1051 | return 0; | |
1052 | ||
1053 | retry: | |
697f0a48 | 1054 | if (unlikely(next_task == rq->curr)) { |
f65eda4f | 1055 | WARN_ON(1); |
e8fa1362 | 1056 | return 0; |
f65eda4f | 1057 | } |
e8fa1362 SR |
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 | */ | |
697f0a48 GH |
1064 | if (unlikely(next_task->prio < rq->curr->prio)) { |
1065 | resched_task(rq->curr); | |
e8fa1362 SR |
1066 | return 0; |
1067 | } | |
1068 | ||
697f0a48 | 1069 | /* We might release rq lock */ |
e8fa1362 SR |
1070 | get_task_struct(next_task); |
1071 | ||
1072 | /* find_lock_lowest_rq locks the rq if found */ | |
697f0a48 | 1073 | lowest_rq = find_lock_lowest_rq(next_task, rq); |
e8fa1362 SR |
1074 | if (!lowest_rq) { |
1075 | struct task_struct *task; | |
1076 | /* | |
697f0a48 | 1077 | * find lock_lowest_rq releases rq->lock |
e8fa1362 SR |
1078 | * so it is possible that next_task has changed. |
1079 | * If it has, then try again. | |
1080 | */ | |
697f0a48 | 1081 | task = pick_next_highest_task_rt(rq, -1); |
e8fa1362 SR |
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 | ||
697f0a48 | 1090 | deactivate_task(rq, next_task, 0); |
e8fa1362 SR |
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 | ||
1b12bbc7 | 1096 | double_unlock_balance(rq, lowest_rq); |
e8fa1362 SR |
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 | ||
f65eda4f SR |
1122 | static int pull_rt_task(struct rq *this_rq) |
1123 | { | |
80bf3171 IM |
1124 | int this_cpu = this_rq->cpu, ret = 0, cpu; |
1125 | struct task_struct *p, *next; | |
f65eda4f | 1126 | struct rq *src_rq; |
f65eda4f | 1127 | |
637f5085 | 1128 | if (likely(!rt_overloaded(this_rq))) |
f65eda4f SR |
1129 | return 0; |
1130 | ||
1131 | next = pick_next_task_rt(this_rq); | |
1132 | ||
363ab6f1 | 1133 | for_each_cpu_mask_nr(cpu, this_rq->rd->rto_mask) { |
f65eda4f SR |
1134 | if (this_cpu == cpu) |
1135 | continue; | |
1136 | ||
1137 | src_rq = cpu_rq(cpu); | |
f65eda4f SR |
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; | |
80bf3171 | 1147 | |
f65eda4f SR |
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 | */ | |
614ee1f6 MG |
1156 | if (src_rq->rt.rt_nr_running <= 1) |
1157 | goto skip; | |
f65eda4f | 1158 | |
f65eda4f SR |
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)) | |
614ee1f6 | 1181 | goto skip; |
f65eda4f SR |
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) | |
80bf3171 | 1193 | * |
f65eda4f SR |
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 | } | |
614ee1f6 | 1201 | skip: |
1b12bbc7 | 1202 | double_unlock_balance(this_rq, src_rq); |
f65eda4f SR |
1203 | } |
1204 | ||
1205 | return ret; | |
1206 | } | |
1207 | ||
9a897c5a | 1208 | static void pre_schedule_rt(struct rq *rq, struct task_struct *prev) |
f65eda4f SR |
1209 | { |
1210 | /* Try to pull RT tasks here if we lower this rq's prio */ | |
7f51f298 | 1211 | if (unlikely(rt_task(prev)) && rq->rt.highest_prio > prev->prio) |
f65eda4f SR |
1212 | pull_rt_task(rq); |
1213 | } | |
1214 | ||
9a897c5a | 1215 | static void post_schedule_rt(struct rq *rq) |
e8fa1362 SR |
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 | */ | |
a22d7fc1 | 1224 | if (unlikely(rq->rt.overloaded)) { |
e8fa1362 SR |
1225 | spin_lock_irq(&rq->lock); |
1226 | push_rt_tasks(rq); | |
1227 | spin_unlock_irq(&rq->lock); | |
1228 | } | |
1229 | } | |
1230 | ||
8ae121ac GH |
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 | */ | |
9a897c5a | 1235 | static void task_wake_up_rt(struct rq *rq, struct task_struct *p) |
4642dafd | 1236 | { |
9a897c5a | 1237 | if (!task_running(rq, p) && |
8ae121ac | 1238 | !test_tsk_need_resched(rq->curr) && |
a22d7fc1 | 1239 | rq->rt.overloaded) |
4642dafd SR |
1240 | push_rt_tasks(rq); |
1241 | } | |
1242 | ||
43010659 | 1243 | static unsigned long |
bb44e5d1 | 1244 | load_balance_rt(struct rq *this_rq, int this_cpu, struct rq *busiest, |
e1d1484f PW |
1245 | unsigned long max_load_move, |
1246 | struct sched_domain *sd, enum cpu_idle_type idle, | |
1247 | int *all_pinned, int *this_best_prio) | |
bb44e5d1 | 1248 | { |
c7a1e46a SR |
1249 | /* don't touch RT tasks */ |
1250 | return 0; | |
e1d1484f PW |
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 | { | |
c7a1e46a SR |
1257 | /* don't touch RT tasks */ |
1258 | return 0; | |
bb44e5d1 | 1259 | } |
deeeccd4 | 1260 | |
cd8ba7cd MT |
1261 | static void set_cpus_allowed_rt(struct task_struct *p, |
1262 | const cpumask_t *new_mask) | |
73fe6aae GH |
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 | */ | |
6f505b16 | 1272 | if (p->se.on_rq && (weight != p->rt.nr_cpus_allowed)) { |
73fe6aae GH |
1273 | struct rq *rq = task_rq(p); |
1274 | ||
6f505b16 | 1275 | if ((p->rt.nr_cpus_allowed <= 1) && (weight > 1)) { |
73fe6aae | 1276 | rq->rt.rt_nr_migratory++; |
6f505b16 | 1277 | } else if ((p->rt.nr_cpus_allowed > 1) && (weight <= 1)) { |
73fe6aae GH |
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; | |
6f505b16 | 1286 | p->rt.nr_cpus_allowed = weight; |
73fe6aae | 1287 | } |
deeeccd4 | 1288 | |
bdd7c81b | 1289 | /* Assumes rq->lock is held */ |
1f11eb6a | 1290 | static void rq_online_rt(struct rq *rq) |
bdd7c81b IM |
1291 | { |
1292 | if (rq->rt.overloaded) | |
1293 | rt_set_overload(rq); | |
6e0534f2 | 1294 | |
7def2be1 PZ |
1295 | __enable_runtime(rq); |
1296 | ||
6e0534f2 | 1297 | cpupri_set(&rq->rd->cpupri, rq->cpu, rq->rt.highest_prio); |
bdd7c81b IM |
1298 | } |
1299 | ||
1300 | /* Assumes rq->lock is held */ | |
1f11eb6a | 1301 | static void rq_offline_rt(struct rq *rq) |
bdd7c81b IM |
1302 | { |
1303 | if (rq->rt.overloaded) | |
1304 | rt_clear_overload(rq); | |
6e0534f2 | 1305 | |
7def2be1 PZ |
1306 | __disable_runtime(rq); |
1307 | ||
6e0534f2 | 1308 | cpupri_set(&rq->rd->cpupri, rq->cpu, CPUPRI_INVALID); |
bdd7c81b | 1309 | } |
cb469845 SR |
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 | |
6fa46fa5 SR |
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. | |
cb469845 | 1379 | */ |
6fa46fa5 | 1380 | if (p->prio > rq->rt.highest_prio && rq->curr == p) |
cb469845 SR |
1381 | resched_task(p); |
1382 | #else | |
1383 | /* For UP simply resched on drop of prio */ | |
1384 | if (oldprio < p->prio) | |
1385 | resched_task(p); | |
e8fa1362 | 1386 | #endif /* CONFIG_SMP */ |
cb469845 SR |
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 | ||
78f2c7db PZ |
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); | |
5a52dd50 | 1413 | if (p->rt.timeout > next) |
78f2c7db PZ |
1414 | p->it_sched_expires = p->se.sum_exec_runtime; |
1415 | } | |
1416 | } | |
bb44e5d1 | 1417 | |
8f4d37ec | 1418 | static void task_tick_rt(struct rq *rq, struct task_struct *p, int queued) |
bb44e5d1 | 1419 | { |
67e2be02 PZ |
1420 | update_curr_rt(rq); |
1421 | ||
78f2c7db PZ |
1422 | watchdog(rq, p); |
1423 | ||
bb44e5d1 IM |
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 | ||
fa717060 | 1431 | if (--p->rt.time_slice) |
bb44e5d1 IM |
1432 | return; |
1433 | ||
fa717060 | 1434 | p->rt.time_slice = DEF_TIMESLICE; |
bb44e5d1 | 1435 | |
98fbc798 DA |
1436 | /* |
1437 | * Requeue to the end of queue if we are not the only element | |
1438 | * on the queue: | |
1439 | */ | |
fa717060 | 1440 | if (p->rt.run_list.prev != p->rt.run_list.next) { |
7ebefa8c | 1441 | requeue_task_rt(rq, p, 0); |
98fbc798 DA |
1442 | set_tsk_need_resched(p); |
1443 | } | |
bb44e5d1 IM |
1444 | } |
1445 | ||
83b699ed SV |
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 | ||
2abdad0a | 1453 | static const struct sched_class rt_sched_class = { |
5522d5d5 | 1454 | .next = &fair_sched_class, |
bb44e5d1 IM |
1455 | .enqueue_task = enqueue_task_rt, |
1456 | .dequeue_task = dequeue_task_rt, | |
1457 | .yield_task = yield_task_rt, | |
e7693a36 GH |
1458 | #ifdef CONFIG_SMP |
1459 | .select_task_rq = select_task_rq_rt, | |
1460 | #endif /* CONFIG_SMP */ | |
bb44e5d1 IM |
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 | ||
681f3e68 | 1467 | #ifdef CONFIG_SMP |
bb44e5d1 | 1468 | .load_balance = load_balance_rt, |
e1d1484f | 1469 | .move_one_task = move_one_task_rt, |
73fe6aae | 1470 | .set_cpus_allowed = set_cpus_allowed_rt, |
1f11eb6a GH |
1471 | .rq_online = rq_online_rt, |
1472 | .rq_offline = rq_offline_rt, | |
9a897c5a SR |
1473 | .pre_schedule = pre_schedule_rt, |
1474 | .post_schedule = post_schedule_rt, | |
1475 | .task_wake_up = task_wake_up_rt, | |
cb469845 | 1476 | .switched_from = switched_from_rt, |
681f3e68 | 1477 | #endif |
bb44e5d1 | 1478 | |
83b699ed | 1479 | .set_curr_task = set_curr_task_rt, |
bb44e5d1 | 1480 | .task_tick = task_tick_rt, |
cb469845 SR |
1481 | |
1482 | .prio_changed = prio_changed_rt, | |
1483 | .switched_to = switched_to_rt, | |
bb44e5d1 | 1484 | }; |
ada18de2 PZ |
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 | } | |
55e12e5e | 1498 | #endif /* CONFIG_SCHED_DEBUG */ |