]>
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 | ||
d0b27fa7 PZ |
164 | #else |
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 | ||
6f505b16 PZ |
229 | #endif |
230 | ||
d0b27fa7 PZ |
231 | static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun) |
232 | { | |
233 | int i, idle = 1; | |
234 | cpumask_t span; | |
235 | ||
236 | if (rt_b->rt_runtime == RUNTIME_INF) | |
237 | return 1; | |
238 | ||
239 | span = sched_rt_period_mask(); | |
240 | for_each_cpu_mask(i, span) { | |
241 | int enqueue = 0; | |
242 | struct rt_rq *rt_rq = sched_rt_period_rt_rq(rt_b, i); | |
243 | struct rq *rq = rq_of_rt_rq(rt_rq); | |
244 | ||
245 | spin_lock(&rq->lock); | |
246 | if (rt_rq->rt_time) { | |
ac086bc2 | 247 | u64 runtime; |
d0b27fa7 | 248 | |
ac086bc2 PZ |
249 | spin_lock(&rt_rq->rt_runtime_lock); |
250 | runtime = rt_rq->rt_runtime; | |
d0b27fa7 PZ |
251 | rt_rq->rt_time -= min(rt_rq->rt_time, overrun*runtime); |
252 | if (rt_rq->rt_throttled && rt_rq->rt_time < runtime) { | |
253 | rt_rq->rt_throttled = 0; | |
254 | enqueue = 1; | |
255 | } | |
256 | if (rt_rq->rt_time || rt_rq->rt_nr_running) | |
257 | idle = 0; | |
ac086bc2 | 258 | spin_unlock(&rt_rq->rt_runtime_lock); |
d0b27fa7 PZ |
259 | } |
260 | ||
261 | if (enqueue) | |
262 | sched_rt_rq_enqueue(rt_rq); | |
263 | spin_unlock(&rq->lock); | |
264 | } | |
265 | ||
266 | return idle; | |
267 | } | |
268 | ||
ac086bc2 PZ |
269 | #ifdef CONFIG_SMP |
270 | static int balance_runtime(struct rt_rq *rt_rq) | |
271 | { | |
272 | struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq); | |
273 | struct root_domain *rd = cpu_rq(smp_processor_id())->rd; | |
274 | int i, weight, more = 0; | |
275 | u64 rt_period; | |
276 | ||
277 | weight = cpus_weight(rd->span); | |
278 | ||
279 | spin_lock(&rt_b->rt_runtime_lock); | |
280 | rt_period = ktime_to_ns(rt_b->rt_period); | |
281 | for_each_cpu_mask(i, rd->span) { | |
282 | struct rt_rq *iter = sched_rt_period_rt_rq(rt_b, i); | |
283 | s64 diff; | |
284 | ||
285 | if (iter == rt_rq) | |
286 | continue; | |
287 | ||
288 | spin_lock(&iter->rt_runtime_lock); | |
7def2be1 PZ |
289 | if (iter->rt_runtime == RUNTIME_INF) |
290 | goto next; | |
291 | ||
ac086bc2 PZ |
292 | diff = iter->rt_runtime - iter->rt_time; |
293 | if (diff > 0) { | |
294 | do_div(diff, weight); | |
295 | if (rt_rq->rt_runtime + diff > rt_period) | |
296 | diff = rt_period - rt_rq->rt_runtime; | |
297 | iter->rt_runtime -= diff; | |
298 | rt_rq->rt_runtime += diff; | |
299 | more = 1; | |
300 | if (rt_rq->rt_runtime == rt_period) { | |
301 | spin_unlock(&iter->rt_runtime_lock); | |
302 | break; | |
303 | } | |
304 | } | |
7def2be1 | 305 | next: |
ac086bc2 PZ |
306 | spin_unlock(&iter->rt_runtime_lock); |
307 | } | |
308 | spin_unlock(&rt_b->rt_runtime_lock); | |
309 | ||
310 | return more; | |
311 | } | |
7def2be1 PZ |
312 | |
313 | static void __disable_runtime(struct rq *rq) | |
314 | { | |
315 | struct root_domain *rd = rq->rd; | |
316 | struct rt_rq *rt_rq; | |
317 | ||
318 | if (unlikely(!scheduler_running)) | |
319 | return; | |
320 | ||
321 | for_each_leaf_rt_rq(rt_rq, rq) { | |
322 | struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq); | |
323 | s64 want; | |
324 | int i; | |
325 | ||
326 | spin_lock(&rt_b->rt_runtime_lock); | |
327 | spin_lock(&rt_rq->rt_runtime_lock); | |
328 | if (rt_rq->rt_runtime == RUNTIME_INF || | |
329 | rt_rq->rt_runtime == rt_b->rt_runtime) | |
330 | goto balanced; | |
331 | spin_unlock(&rt_rq->rt_runtime_lock); | |
332 | ||
333 | want = rt_b->rt_runtime - rt_rq->rt_runtime; | |
334 | ||
335 | for_each_cpu_mask(i, rd->span) { | |
336 | struct rt_rq *iter = sched_rt_period_rt_rq(rt_b, i); | |
337 | s64 diff; | |
338 | ||
339 | if (iter == rt_rq) | |
340 | continue; | |
341 | ||
342 | spin_lock(&iter->rt_runtime_lock); | |
343 | if (want > 0) { | |
344 | diff = min_t(s64, iter->rt_runtime, want); | |
345 | iter->rt_runtime -= diff; | |
346 | want -= diff; | |
347 | } else { | |
348 | iter->rt_runtime -= want; | |
349 | want -= want; | |
350 | } | |
351 | spin_unlock(&iter->rt_runtime_lock); | |
352 | ||
353 | if (!want) | |
354 | break; | |
355 | } | |
356 | ||
357 | spin_lock(&rt_rq->rt_runtime_lock); | |
358 | BUG_ON(want); | |
359 | balanced: | |
360 | rt_rq->rt_runtime = RUNTIME_INF; | |
361 | spin_unlock(&rt_rq->rt_runtime_lock); | |
362 | spin_unlock(&rt_b->rt_runtime_lock); | |
363 | } | |
364 | } | |
365 | ||
366 | static void disable_runtime(struct rq *rq) | |
367 | { | |
368 | unsigned long flags; | |
369 | ||
370 | spin_lock_irqsave(&rq->lock, flags); | |
371 | __disable_runtime(rq); | |
372 | spin_unlock_irqrestore(&rq->lock, flags); | |
373 | } | |
374 | ||
375 | static void __enable_runtime(struct rq *rq) | |
376 | { | |
377 | struct root_domain *rd = rq->rd; | |
378 | struct rt_rq *rt_rq; | |
379 | ||
380 | if (unlikely(!scheduler_running)) | |
381 | return; | |
382 | ||
383 | for_each_leaf_rt_rq(rt_rq, rq) { | |
384 | struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq); | |
385 | ||
386 | spin_lock(&rt_b->rt_runtime_lock); | |
387 | spin_lock(&rt_rq->rt_runtime_lock); | |
388 | rt_rq->rt_runtime = rt_b->rt_runtime; | |
389 | rt_rq->rt_time = 0; | |
390 | spin_unlock(&rt_rq->rt_runtime_lock); | |
391 | spin_unlock(&rt_b->rt_runtime_lock); | |
392 | } | |
393 | } | |
394 | ||
395 | static void enable_runtime(struct rq *rq) | |
396 | { | |
397 | unsigned long flags; | |
398 | ||
399 | spin_lock_irqsave(&rq->lock, flags); | |
400 | __enable_runtime(rq); | |
401 | spin_unlock_irqrestore(&rq->lock, flags); | |
402 | } | |
403 | ||
ac086bc2 PZ |
404 | #endif |
405 | ||
6f505b16 PZ |
406 | static inline int rt_se_prio(struct sched_rt_entity *rt_se) |
407 | { | |
052f1dc7 | 408 | #ifdef CONFIG_RT_GROUP_SCHED |
6f505b16 PZ |
409 | struct rt_rq *rt_rq = group_rt_rq(rt_se); |
410 | ||
411 | if (rt_rq) | |
412 | return rt_rq->highest_prio; | |
413 | #endif | |
414 | ||
415 | return rt_task_of(rt_se)->prio; | |
416 | } | |
417 | ||
9f0c1e56 | 418 | static int sched_rt_runtime_exceeded(struct rt_rq *rt_rq) |
6f505b16 | 419 | { |
9f0c1e56 | 420 | u64 runtime = sched_rt_runtime(rt_rq); |
fa85ae24 | 421 | |
9f0c1e56 | 422 | if (runtime == RUNTIME_INF) |
fa85ae24 PZ |
423 | return 0; |
424 | ||
425 | if (rt_rq->rt_throttled) | |
23b0fdfc | 426 | return rt_rq_throttled(rt_rq); |
fa85ae24 | 427 | |
ac086bc2 PZ |
428 | if (sched_rt_runtime(rt_rq) >= sched_rt_period(rt_rq)) |
429 | return 0; | |
430 | ||
431 | #ifdef CONFIG_SMP | |
432 | if (rt_rq->rt_time > runtime) { | |
ac086bc2 | 433 | spin_unlock(&rt_rq->rt_runtime_lock); |
7def2be1 | 434 | balance_runtime(rt_rq); |
ac086bc2 PZ |
435 | spin_lock(&rt_rq->rt_runtime_lock); |
436 | ||
7def2be1 PZ |
437 | runtime = sched_rt_runtime(rt_rq); |
438 | if (runtime == RUNTIME_INF) | |
439 | return 0; | |
ac086bc2 PZ |
440 | } |
441 | #endif | |
442 | ||
9f0c1e56 | 443 | if (rt_rq->rt_time > runtime) { |
6f505b16 | 444 | rt_rq->rt_throttled = 1; |
23b0fdfc | 445 | if (rt_rq_throttled(rt_rq)) { |
9f0c1e56 | 446 | sched_rt_rq_dequeue(rt_rq); |
23b0fdfc PZ |
447 | return 1; |
448 | } | |
fa85ae24 PZ |
449 | } |
450 | ||
451 | return 0; | |
452 | } | |
453 | ||
bb44e5d1 IM |
454 | /* |
455 | * Update the current task's runtime statistics. Skip current tasks that | |
456 | * are not in our scheduling class. | |
457 | */ | |
a9957449 | 458 | static void update_curr_rt(struct rq *rq) |
bb44e5d1 IM |
459 | { |
460 | struct task_struct *curr = rq->curr; | |
6f505b16 PZ |
461 | struct sched_rt_entity *rt_se = &curr->rt; |
462 | struct rt_rq *rt_rq = rt_rq_of_se(rt_se); | |
bb44e5d1 IM |
463 | u64 delta_exec; |
464 | ||
465 | if (!task_has_rt_policy(curr)) | |
466 | return; | |
467 | ||
d281918d | 468 | delta_exec = rq->clock - curr->se.exec_start; |
bb44e5d1 IM |
469 | if (unlikely((s64)delta_exec < 0)) |
470 | delta_exec = 0; | |
6cfb0d5d IM |
471 | |
472 | schedstat_set(curr->se.exec_max, max(curr->se.exec_max, delta_exec)); | |
bb44e5d1 IM |
473 | |
474 | curr->se.sum_exec_runtime += delta_exec; | |
d281918d | 475 | curr->se.exec_start = rq->clock; |
d842de87 | 476 | cpuacct_charge(curr, delta_exec); |
fa85ae24 | 477 | |
354d60c2 DG |
478 | for_each_sched_rt_entity(rt_se) { |
479 | rt_rq = rt_rq_of_se(rt_se); | |
480 | ||
481 | spin_lock(&rt_rq->rt_runtime_lock); | |
482 | rt_rq->rt_time += delta_exec; | |
483 | if (sched_rt_runtime_exceeded(rt_rq)) | |
484 | resched_task(curr); | |
485 | spin_unlock(&rt_rq->rt_runtime_lock); | |
486 | } | |
bb44e5d1 IM |
487 | } |
488 | ||
6f505b16 PZ |
489 | static inline |
490 | void inc_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) | |
63489e45 | 491 | { |
6f505b16 PZ |
492 | WARN_ON(!rt_prio(rt_se_prio(rt_se))); |
493 | rt_rq->rt_nr_running++; | |
052f1dc7 | 494 | #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED |
6e0534f2 GH |
495 | if (rt_se_prio(rt_se) < rt_rq->highest_prio) { |
496 | struct rq *rq = rq_of_rt_rq(rt_rq); | |
1f11eb6a | 497 | |
1100ac91 IM |
498 | rt_rq->highest_prio = rt_se_prio(rt_se); |
499 | #ifdef CONFIG_SMP | |
1f11eb6a GH |
500 | if (rq->online) |
501 | cpupri_set(&rq->rd->cpupri, rq->cpu, | |
502 | rt_se_prio(rt_se)); | |
1100ac91 | 503 | #endif |
6e0534f2 | 504 | } |
6f505b16 | 505 | #endif |
764a9d6f | 506 | #ifdef CONFIG_SMP |
6f505b16 PZ |
507 | if (rt_se->nr_cpus_allowed > 1) { |
508 | struct rq *rq = rq_of_rt_rq(rt_rq); | |
1100ac91 | 509 | |
73fe6aae | 510 | rq->rt.rt_nr_migratory++; |
6f505b16 | 511 | } |
73fe6aae | 512 | |
6f505b16 PZ |
513 | update_rt_migration(rq_of_rt_rq(rt_rq)); |
514 | #endif | |
052f1dc7 | 515 | #ifdef CONFIG_RT_GROUP_SCHED |
23b0fdfc PZ |
516 | if (rt_se_boosted(rt_se)) |
517 | rt_rq->rt_nr_boosted++; | |
d0b27fa7 PZ |
518 | |
519 | if (rt_rq->tg) | |
520 | start_rt_bandwidth(&rt_rq->tg->rt_bandwidth); | |
521 | #else | |
522 | start_rt_bandwidth(&def_rt_bandwidth); | |
23b0fdfc | 523 | #endif |
63489e45 SR |
524 | } |
525 | ||
6f505b16 PZ |
526 | static inline |
527 | void dec_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) | |
63489e45 | 528 | { |
6e0534f2 GH |
529 | #ifdef CONFIG_SMP |
530 | int highest_prio = rt_rq->highest_prio; | |
531 | #endif | |
532 | ||
6f505b16 PZ |
533 | WARN_ON(!rt_prio(rt_se_prio(rt_se))); |
534 | WARN_ON(!rt_rq->rt_nr_running); | |
535 | rt_rq->rt_nr_running--; | |
052f1dc7 | 536 | #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED |
6f505b16 | 537 | if (rt_rq->rt_nr_running) { |
764a9d6f SR |
538 | struct rt_prio_array *array; |
539 | ||
6f505b16 PZ |
540 | WARN_ON(rt_se_prio(rt_se) < rt_rq->highest_prio); |
541 | if (rt_se_prio(rt_se) == rt_rq->highest_prio) { | |
764a9d6f | 542 | /* recalculate */ |
6f505b16 PZ |
543 | array = &rt_rq->active; |
544 | rt_rq->highest_prio = | |
764a9d6f SR |
545 | sched_find_first_bit(array->bitmap); |
546 | } /* otherwise leave rq->highest prio alone */ | |
547 | } else | |
6f505b16 PZ |
548 | rt_rq->highest_prio = MAX_RT_PRIO; |
549 | #endif | |
550 | #ifdef CONFIG_SMP | |
551 | if (rt_se->nr_cpus_allowed > 1) { | |
552 | struct rq *rq = rq_of_rt_rq(rt_rq); | |
73fe6aae | 553 | rq->rt.rt_nr_migratory--; |
6f505b16 | 554 | } |
73fe6aae | 555 | |
6e0534f2 GH |
556 | if (rt_rq->highest_prio != highest_prio) { |
557 | struct rq *rq = rq_of_rt_rq(rt_rq); | |
1f11eb6a GH |
558 | |
559 | if (rq->online) | |
560 | cpupri_set(&rq->rd->cpupri, rq->cpu, | |
561 | rt_rq->highest_prio); | |
6e0534f2 GH |
562 | } |
563 | ||
6f505b16 | 564 | update_rt_migration(rq_of_rt_rq(rt_rq)); |
764a9d6f | 565 | #endif /* CONFIG_SMP */ |
052f1dc7 | 566 | #ifdef CONFIG_RT_GROUP_SCHED |
23b0fdfc PZ |
567 | if (rt_se_boosted(rt_se)) |
568 | rt_rq->rt_nr_boosted--; | |
569 | ||
570 | WARN_ON(!rt_rq->rt_nr_running && rt_rq->rt_nr_boosted); | |
571 | #endif | |
63489e45 SR |
572 | } |
573 | ||
ad2a3f13 | 574 | static void __enqueue_rt_entity(struct sched_rt_entity *rt_se) |
bb44e5d1 | 575 | { |
6f505b16 PZ |
576 | struct rt_rq *rt_rq = rt_rq_of_se(rt_se); |
577 | struct rt_prio_array *array = &rt_rq->active; | |
578 | struct rt_rq *group_rq = group_rt_rq(rt_se); | |
20b6331b | 579 | struct list_head *queue = array->queue + rt_se_prio(rt_se); |
bb44e5d1 | 580 | |
ad2a3f13 PZ |
581 | /* |
582 | * Don't enqueue the group if its throttled, or when empty. | |
583 | * The latter is a consequence of the former when a child group | |
584 | * get throttled and the current group doesn't have any other | |
585 | * active members. | |
586 | */ | |
587 | if (group_rq && (rt_rq_throttled(group_rq) || !group_rq->rt_nr_running)) | |
6f505b16 | 588 | return; |
63489e45 | 589 | |
45c01e82 | 590 | if (rt_se->nr_cpus_allowed == 1) |
20b6331b | 591 | list_add(&rt_se->run_list, queue); |
45c01e82 | 592 | else |
20b6331b | 593 | list_add_tail(&rt_se->run_list, queue); |
45c01e82 | 594 | |
6f505b16 | 595 | __set_bit(rt_se_prio(rt_se), array->bitmap); |
78f2c7db | 596 | |
6f505b16 PZ |
597 | inc_rt_tasks(rt_se, rt_rq); |
598 | } | |
599 | ||
ad2a3f13 | 600 | static void __dequeue_rt_entity(struct sched_rt_entity *rt_se) |
6f505b16 PZ |
601 | { |
602 | struct rt_rq *rt_rq = rt_rq_of_se(rt_se); | |
603 | struct rt_prio_array *array = &rt_rq->active; | |
604 | ||
605 | list_del_init(&rt_se->run_list); | |
20b6331b | 606 | if (list_empty(array->queue + rt_se_prio(rt_se))) |
6f505b16 PZ |
607 | __clear_bit(rt_se_prio(rt_se), array->bitmap); |
608 | ||
609 | dec_rt_tasks(rt_se, rt_rq); | |
610 | } | |
611 | ||
612 | /* | |
613 | * Because the prio of an upper entry depends on the lower | |
614 | * entries, we must remove entries top - down. | |
6f505b16 | 615 | */ |
ad2a3f13 | 616 | static void dequeue_rt_stack(struct sched_rt_entity *rt_se) |
6f505b16 | 617 | { |
ad2a3f13 | 618 | struct sched_rt_entity *back = NULL; |
6f505b16 | 619 | |
58d6c2d7 PZ |
620 | for_each_sched_rt_entity(rt_se) { |
621 | rt_se->back = back; | |
622 | back = rt_se; | |
623 | } | |
624 | ||
625 | for (rt_se = back; rt_se; rt_se = rt_se->back) { | |
626 | if (on_rt_rq(rt_se)) | |
ad2a3f13 PZ |
627 | __dequeue_rt_entity(rt_se); |
628 | } | |
629 | } | |
630 | ||
631 | static void enqueue_rt_entity(struct sched_rt_entity *rt_se) | |
632 | { | |
633 | dequeue_rt_stack(rt_se); | |
634 | for_each_sched_rt_entity(rt_se) | |
635 | __enqueue_rt_entity(rt_se); | |
636 | } | |
637 | ||
638 | static void dequeue_rt_entity(struct sched_rt_entity *rt_se) | |
639 | { | |
640 | dequeue_rt_stack(rt_se); | |
641 | ||
642 | for_each_sched_rt_entity(rt_se) { | |
643 | struct rt_rq *rt_rq = group_rt_rq(rt_se); | |
644 | ||
645 | if (rt_rq && rt_rq->rt_nr_running) | |
646 | __enqueue_rt_entity(rt_se); | |
58d6c2d7 | 647 | } |
bb44e5d1 IM |
648 | } |
649 | ||
650 | /* | |
651 | * Adding/removing a task to/from a priority array: | |
652 | */ | |
6f505b16 PZ |
653 | static void enqueue_task_rt(struct rq *rq, struct task_struct *p, int wakeup) |
654 | { | |
655 | struct sched_rt_entity *rt_se = &p->rt; | |
656 | ||
657 | if (wakeup) | |
658 | rt_se->timeout = 0; | |
659 | ||
ad2a3f13 | 660 | enqueue_rt_entity(rt_se); |
6f505b16 PZ |
661 | } |
662 | ||
f02231e5 | 663 | static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int sleep) |
bb44e5d1 | 664 | { |
6f505b16 | 665 | struct sched_rt_entity *rt_se = &p->rt; |
bb44e5d1 | 666 | |
f1e14ef6 | 667 | update_curr_rt(rq); |
ad2a3f13 | 668 | dequeue_rt_entity(rt_se); |
bb44e5d1 IM |
669 | } |
670 | ||
671 | /* | |
672 | * Put task to the end of the run list without the overhead of dequeue | |
673 | * followed by enqueue. | |
674 | */ | |
6f505b16 PZ |
675 | static |
676 | void requeue_rt_entity(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se) | |
677 | { | |
678 | struct rt_prio_array *array = &rt_rq->active; | |
15a8641e | 679 | struct list_head *queue = array->queue + rt_se_prio(rt_se); |
6f505b16 | 680 | |
1cdad715 IM |
681 | if (on_rt_rq(rt_se)) { |
682 | list_del_init(&rt_se->run_list); | |
683 | list_add_tail(&rt_se->run_list, | |
684 | array->queue + rt_se_prio(rt_se)); | |
685 | } | |
6f505b16 PZ |
686 | } |
687 | ||
bb44e5d1 IM |
688 | static void requeue_task_rt(struct rq *rq, struct task_struct *p) |
689 | { | |
6f505b16 PZ |
690 | struct sched_rt_entity *rt_se = &p->rt; |
691 | struct rt_rq *rt_rq; | |
bb44e5d1 | 692 | |
6f505b16 PZ |
693 | for_each_sched_rt_entity(rt_se) { |
694 | rt_rq = rt_rq_of_se(rt_se); | |
695 | requeue_rt_entity(rt_rq, rt_se); | |
696 | } | |
bb44e5d1 IM |
697 | } |
698 | ||
6f505b16 | 699 | static void yield_task_rt(struct rq *rq) |
bb44e5d1 | 700 | { |
4530d7ab | 701 | requeue_task_rt(rq, rq->curr); |
bb44e5d1 IM |
702 | } |
703 | ||
e7693a36 | 704 | #ifdef CONFIG_SMP |
318e0893 GH |
705 | static int find_lowest_rq(struct task_struct *task); |
706 | ||
e7693a36 GH |
707 | static int select_task_rq_rt(struct task_struct *p, int sync) |
708 | { | |
318e0893 GH |
709 | struct rq *rq = task_rq(p); |
710 | ||
711 | /* | |
e1f47d89 SR |
712 | * If the current task is an RT task, then |
713 | * try to see if we can wake this RT task up on another | |
714 | * runqueue. Otherwise simply start this RT task | |
715 | * on its current runqueue. | |
716 | * | |
717 | * We want to avoid overloading runqueues. Even if | |
718 | * the RT task is of higher priority than the current RT task. | |
719 | * RT tasks behave differently than other tasks. If | |
720 | * one gets preempted, we try to push it off to another queue. | |
721 | * So trying to keep a preempting RT task on the same | |
722 | * cache hot CPU will force the running RT task to | |
723 | * a cold CPU. So we waste all the cache for the lower | |
724 | * RT task in hopes of saving some of a RT task | |
725 | * that is just being woken and probably will have | |
726 | * cold cache anyway. | |
318e0893 | 727 | */ |
17b3279b | 728 | if (unlikely(rt_task(rq->curr)) && |
6f505b16 | 729 | (p->rt.nr_cpus_allowed > 1)) { |
318e0893 GH |
730 | int cpu = find_lowest_rq(p); |
731 | ||
732 | return (cpu == -1) ? task_cpu(p) : cpu; | |
733 | } | |
734 | ||
735 | /* | |
736 | * Otherwise, just let it ride on the affined RQ and the | |
737 | * post-schedule router will push the preempted task away | |
738 | */ | |
e7693a36 GH |
739 | return task_cpu(p); |
740 | } | |
741 | #endif /* CONFIG_SMP */ | |
742 | ||
bb44e5d1 IM |
743 | /* |
744 | * Preempt the current task with a newly woken task if needed: | |
745 | */ | |
746 | static void check_preempt_curr_rt(struct rq *rq, struct task_struct *p) | |
747 | { | |
45c01e82 | 748 | if (p->prio < rq->curr->prio) { |
bb44e5d1 | 749 | resched_task(rq->curr); |
45c01e82 GH |
750 | return; |
751 | } | |
752 | ||
753 | #ifdef CONFIG_SMP | |
754 | /* | |
755 | * If: | |
756 | * | |
757 | * - the newly woken task is of equal priority to the current task | |
758 | * - the newly woken task is non-migratable while current is migratable | |
759 | * - current will be preempted on the next reschedule | |
760 | * | |
761 | * we should check to see if current can readily move to a different | |
762 | * cpu. If so, we will reschedule to allow the push logic to try | |
763 | * to move current somewhere else, making room for our non-migratable | |
764 | * task. | |
765 | */ | |
766 | if((p->prio == rq->curr->prio) | |
767 | && p->rt.nr_cpus_allowed == 1 | |
20b6331b | 768 | && rq->curr->rt.nr_cpus_allowed != 1) { |
45c01e82 GH |
769 | cpumask_t mask; |
770 | ||
771 | if (cpupri_find(&rq->rd->cpupri, rq->curr, &mask)) | |
772 | /* | |
773 | * There appears to be other cpus that can accept | |
774 | * current, so lets reschedule to try and push it away | |
775 | */ | |
776 | resched_task(rq->curr); | |
777 | } | |
778 | #endif | |
bb44e5d1 IM |
779 | } |
780 | ||
6f505b16 PZ |
781 | static struct sched_rt_entity *pick_next_rt_entity(struct rq *rq, |
782 | struct rt_rq *rt_rq) | |
bb44e5d1 | 783 | { |
6f505b16 PZ |
784 | struct rt_prio_array *array = &rt_rq->active; |
785 | struct sched_rt_entity *next = NULL; | |
bb44e5d1 IM |
786 | struct list_head *queue; |
787 | int idx; | |
788 | ||
789 | idx = sched_find_first_bit(array->bitmap); | |
6f505b16 | 790 | BUG_ON(idx >= MAX_RT_PRIO); |
bb44e5d1 | 791 | |
20b6331b DA |
792 | queue = array->queue + idx; |
793 | next = list_entry(queue->next, struct sched_rt_entity, run_list); | |
326587b8 | 794 | |
6f505b16 PZ |
795 | return next; |
796 | } | |
bb44e5d1 | 797 | |
6f505b16 PZ |
798 | static struct task_struct *pick_next_task_rt(struct rq *rq) |
799 | { | |
800 | struct sched_rt_entity *rt_se; | |
801 | struct task_struct *p; | |
802 | struct rt_rq *rt_rq; | |
bb44e5d1 | 803 | |
6f505b16 PZ |
804 | rt_rq = &rq->rt; |
805 | ||
806 | if (unlikely(!rt_rq->rt_nr_running)) | |
807 | return NULL; | |
808 | ||
23b0fdfc | 809 | if (rt_rq_throttled(rt_rq)) |
6f505b16 PZ |
810 | return NULL; |
811 | ||
812 | do { | |
813 | rt_se = pick_next_rt_entity(rq, rt_rq); | |
326587b8 | 814 | BUG_ON(!rt_se); |
6f505b16 PZ |
815 | rt_rq = group_rt_rq(rt_se); |
816 | } while (rt_rq); | |
817 | ||
818 | p = rt_task_of(rt_se); | |
819 | p->se.exec_start = rq->clock; | |
820 | return p; | |
bb44e5d1 IM |
821 | } |
822 | ||
31ee529c | 823 | static void put_prev_task_rt(struct rq *rq, struct task_struct *p) |
bb44e5d1 | 824 | { |
f1e14ef6 | 825 | update_curr_rt(rq); |
bb44e5d1 IM |
826 | p->se.exec_start = 0; |
827 | } | |
828 | ||
681f3e68 | 829 | #ifdef CONFIG_SMP |
6f505b16 | 830 | |
e8fa1362 SR |
831 | /* Only try algorithms three times */ |
832 | #define RT_MAX_TRIES 3 | |
833 | ||
834 | static int double_lock_balance(struct rq *this_rq, struct rq *busiest); | |
835 | static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep); | |
836 | ||
f65eda4f SR |
837 | static int pick_rt_task(struct rq *rq, struct task_struct *p, int cpu) |
838 | { | |
839 | if (!task_running(rq, p) && | |
73fe6aae | 840 | (cpu < 0 || cpu_isset(cpu, p->cpus_allowed)) && |
6f505b16 | 841 | (p->rt.nr_cpus_allowed > 1)) |
f65eda4f SR |
842 | return 1; |
843 | return 0; | |
844 | } | |
845 | ||
e8fa1362 | 846 | /* Return the second highest RT task, NULL otherwise */ |
79064fbf | 847 | static struct task_struct *pick_next_highest_task_rt(struct rq *rq, int cpu) |
e8fa1362 | 848 | { |
6f505b16 PZ |
849 | struct task_struct *next = NULL; |
850 | struct sched_rt_entity *rt_se; | |
851 | struct rt_prio_array *array; | |
852 | struct rt_rq *rt_rq; | |
e8fa1362 SR |
853 | int idx; |
854 | ||
6f505b16 PZ |
855 | for_each_leaf_rt_rq(rt_rq, rq) { |
856 | array = &rt_rq->active; | |
857 | idx = sched_find_first_bit(array->bitmap); | |
858 | next_idx: | |
859 | if (idx >= MAX_RT_PRIO) | |
860 | continue; | |
861 | if (next && next->prio < idx) | |
862 | continue; | |
20b6331b | 863 | list_for_each_entry(rt_se, array->queue + idx, run_list) { |
6f505b16 PZ |
864 | struct task_struct *p = rt_task_of(rt_se); |
865 | if (pick_rt_task(rq, p, cpu)) { | |
866 | next = p; | |
867 | break; | |
868 | } | |
869 | } | |
870 | if (!next) { | |
871 | idx = find_next_bit(array->bitmap, MAX_RT_PRIO, idx+1); | |
872 | goto next_idx; | |
873 | } | |
f65eda4f SR |
874 | } |
875 | ||
e8fa1362 SR |
876 | return next; |
877 | } | |
878 | ||
879 | static DEFINE_PER_CPU(cpumask_t, local_cpu_mask); | |
880 | ||
6e1254d2 GH |
881 | static inline int pick_optimal_cpu(int this_cpu, cpumask_t *mask) |
882 | { | |
883 | int first; | |
884 | ||
885 | /* "this_cpu" is cheaper to preempt than a remote processor */ | |
886 | if ((this_cpu != -1) && cpu_isset(this_cpu, *mask)) | |
887 | return this_cpu; | |
888 | ||
889 | first = first_cpu(*mask); | |
890 | if (first != NR_CPUS) | |
891 | return first; | |
892 | ||
893 | return -1; | |
894 | } | |
895 | ||
896 | static int find_lowest_rq(struct task_struct *task) | |
897 | { | |
898 | struct sched_domain *sd; | |
899 | cpumask_t *lowest_mask = &__get_cpu_var(local_cpu_mask); | |
900 | int this_cpu = smp_processor_id(); | |
901 | int cpu = task_cpu(task); | |
06f90dbd | 902 | |
6e0534f2 GH |
903 | if (task->rt.nr_cpus_allowed == 1) |
904 | return -1; /* No other targets possible */ | |
6e1254d2 | 905 | |
6e0534f2 GH |
906 | if (!cpupri_find(&task_rq(task)->rd->cpupri, task, lowest_mask)) |
907 | return -1; /* No targets found */ | |
6e1254d2 GH |
908 | |
909 | /* | |
910 | * At this point we have built a mask of cpus representing the | |
911 | * lowest priority tasks in the system. Now we want to elect | |
912 | * the best one based on our affinity and topology. | |
913 | * | |
914 | * We prioritize the last cpu that the task executed on since | |
915 | * it is most likely cache-hot in that location. | |
916 | */ | |
917 | if (cpu_isset(cpu, *lowest_mask)) | |
918 | return cpu; | |
919 | ||
920 | /* | |
921 | * Otherwise, we consult the sched_domains span maps to figure | |
922 | * out which cpu is logically closest to our hot cache data. | |
923 | */ | |
924 | if (this_cpu == cpu) | |
925 | this_cpu = -1; /* Skip this_cpu opt if the same */ | |
926 | ||
927 | for_each_domain(cpu, sd) { | |
928 | if (sd->flags & SD_WAKE_AFFINE) { | |
929 | cpumask_t domain_mask; | |
930 | int best_cpu; | |
931 | ||
932 | cpus_and(domain_mask, sd->span, *lowest_mask); | |
933 | ||
934 | best_cpu = pick_optimal_cpu(this_cpu, | |
935 | &domain_mask); | |
936 | if (best_cpu != -1) | |
937 | return best_cpu; | |
938 | } | |
939 | } | |
940 | ||
941 | /* | |
942 | * And finally, if there were no matches within the domains | |
943 | * just give the caller *something* to work with from the compatible | |
944 | * locations. | |
945 | */ | |
946 | return pick_optimal_cpu(this_cpu, lowest_mask); | |
07b4032c GH |
947 | } |
948 | ||
949 | /* Will lock the rq it finds */ | |
4df64c0b | 950 | static struct rq *find_lock_lowest_rq(struct task_struct *task, struct rq *rq) |
07b4032c GH |
951 | { |
952 | struct rq *lowest_rq = NULL; | |
07b4032c | 953 | int tries; |
4df64c0b | 954 | int cpu; |
e8fa1362 | 955 | |
07b4032c GH |
956 | for (tries = 0; tries < RT_MAX_TRIES; tries++) { |
957 | cpu = find_lowest_rq(task); | |
958 | ||
2de0b463 | 959 | if ((cpu == -1) || (cpu == rq->cpu)) |
e8fa1362 SR |
960 | break; |
961 | ||
07b4032c GH |
962 | lowest_rq = cpu_rq(cpu); |
963 | ||
e8fa1362 | 964 | /* if the prio of this runqueue changed, try again */ |
07b4032c | 965 | if (double_lock_balance(rq, lowest_rq)) { |
e8fa1362 SR |
966 | /* |
967 | * We had to unlock the run queue. In | |
968 | * the mean time, task could have | |
969 | * migrated already or had its affinity changed. | |
970 | * Also make sure that it wasn't scheduled on its rq. | |
971 | */ | |
07b4032c | 972 | if (unlikely(task_rq(task) != rq || |
4df64c0b IM |
973 | !cpu_isset(lowest_rq->cpu, |
974 | task->cpus_allowed) || | |
07b4032c | 975 | task_running(rq, task) || |
e8fa1362 | 976 | !task->se.on_rq)) { |
4df64c0b | 977 | |
e8fa1362 SR |
978 | spin_unlock(&lowest_rq->lock); |
979 | lowest_rq = NULL; | |
980 | break; | |
981 | } | |
982 | } | |
983 | ||
984 | /* If this rq is still suitable use it. */ | |
985 | if (lowest_rq->rt.highest_prio > task->prio) | |
986 | break; | |
987 | ||
988 | /* try again */ | |
989 | spin_unlock(&lowest_rq->lock); | |
990 | lowest_rq = NULL; | |
991 | } | |
992 | ||
993 | return lowest_rq; | |
994 | } | |
995 | ||
996 | /* | |
997 | * If the current CPU has more than one RT task, see if the non | |
998 | * running task can migrate over to a CPU that is running a task | |
999 | * of lesser priority. | |
1000 | */ | |
697f0a48 | 1001 | static int push_rt_task(struct rq *rq) |
e8fa1362 SR |
1002 | { |
1003 | struct task_struct *next_task; | |
1004 | struct rq *lowest_rq; | |
1005 | int ret = 0; | |
1006 | int paranoid = RT_MAX_TRIES; | |
1007 | ||
a22d7fc1 GH |
1008 | if (!rq->rt.overloaded) |
1009 | return 0; | |
1010 | ||
697f0a48 | 1011 | next_task = pick_next_highest_task_rt(rq, -1); |
e8fa1362 SR |
1012 | if (!next_task) |
1013 | return 0; | |
1014 | ||
1015 | retry: | |
697f0a48 | 1016 | if (unlikely(next_task == rq->curr)) { |
f65eda4f | 1017 | WARN_ON(1); |
e8fa1362 | 1018 | return 0; |
f65eda4f | 1019 | } |
e8fa1362 SR |
1020 | |
1021 | /* | |
1022 | * It's possible that the next_task slipped in of | |
1023 | * higher priority than current. If that's the case | |
1024 | * just reschedule current. | |
1025 | */ | |
697f0a48 GH |
1026 | if (unlikely(next_task->prio < rq->curr->prio)) { |
1027 | resched_task(rq->curr); | |
e8fa1362 SR |
1028 | return 0; |
1029 | } | |
1030 | ||
697f0a48 | 1031 | /* We might release rq lock */ |
e8fa1362 SR |
1032 | get_task_struct(next_task); |
1033 | ||
1034 | /* find_lock_lowest_rq locks the rq if found */ | |
697f0a48 | 1035 | lowest_rq = find_lock_lowest_rq(next_task, rq); |
e8fa1362 SR |
1036 | if (!lowest_rq) { |
1037 | struct task_struct *task; | |
1038 | /* | |
697f0a48 | 1039 | * find lock_lowest_rq releases rq->lock |
e8fa1362 SR |
1040 | * so it is possible that next_task has changed. |
1041 | * If it has, then try again. | |
1042 | */ | |
697f0a48 | 1043 | task = pick_next_highest_task_rt(rq, -1); |
e8fa1362 SR |
1044 | if (unlikely(task != next_task) && task && paranoid--) { |
1045 | put_task_struct(next_task); | |
1046 | next_task = task; | |
1047 | goto retry; | |
1048 | } | |
1049 | goto out; | |
1050 | } | |
1051 | ||
697f0a48 | 1052 | deactivate_task(rq, next_task, 0); |
e8fa1362 SR |
1053 | set_task_cpu(next_task, lowest_rq->cpu); |
1054 | activate_task(lowest_rq, next_task, 0); | |
1055 | ||
1056 | resched_task(lowest_rq->curr); | |
1057 | ||
1058 | spin_unlock(&lowest_rq->lock); | |
1059 | ||
1060 | ret = 1; | |
1061 | out: | |
1062 | put_task_struct(next_task); | |
1063 | ||
1064 | return ret; | |
1065 | } | |
1066 | ||
1067 | /* | |
1068 | * TODO: Currently we just use the second highest prio task on | |
1069 | * the queue, and stop when it can't migrate (or there's | |
1070 | * no more RT tasks). There may be a case where a lower | |
1071 | * priority RT task has a different affinity than the | |
1072 | * higher RT task. In this case the lower RT task could | |
1073 | * possibly be able to migrate where as the higher priority | |
1074 | * RT task could not. We currently ignore this issue. | |
1075 | * Enhancements are welcome! | |
1076 | */ | |
1077 | static void push_rt_tasks(struct rq *rq) | |
1078 | { | |
1079 | /* push_rt_task will return true if it moved an RT */ | |
1080 | while (push_rt_task(rq)) | |
1081 | ; | |
1082 | } | |
1083 | ||
f65eda4f SR |
1084 | static int pull_rt_task(struct rq *this_rq) |
1085 | { | |
80bf3171 IM |
1086 | int this_cpu = this_rq->cpu, ret = 0, cpu; |
1087 | struct task_struct *p, *next; | |
f65eda4f | 1088 | struct rq *src_rq; |
f65eda4f | 1089 | |
637f5085 | 1090 | if (likely(!rt_overloaded(this_rq))) |
f65eda4f SR |
1091 | return 0; |
1092 | ||
1093 | next = pick_next_task_rt(this_rq); | |
1094 | ||
637f5085 | 1095 | for_each_cpu_mask(cpu, this_rq->rd->rto_mask) { |
f65eda4f SR |
1096 | if (this_cpu == cpu) |
1097 | continue; | |
1098 | ||
1099 | src_rq = cpu_rq(cpu); | |
f65eda4f SR |
1100 | /* |
1101 | * We can potentially drop this_rq's lock in | |
1102 | * double_lock_balance, and another CPU could | |
1103 | * steal our next task - hence we must cause | |
1104 | * the caller to recalculate the next task | |
1105 | * in that case: | |
1106 | */ | |
1107 | if (double_lock_balance(this_rq, src_rq)) { | |
1108 | struct task_struct *old_next = next; | |
80bf3171 | 1109 | |
f65eda4f SR |
1110 | next = pick_next_task_rt(this_rq); |
1111 | if (next != old_next) | |
1112 | ret = 1; | |
1113 | } | |
1114 | ||
1115 | /* | |
1116 | * Are there still pullable RT tasks? | |
1117 | */ | |
614ee1f6 MG |
1118 | if (src_rq->rt.rt_nr_running <= 1) |
1119 | goto skip; | |
f65eda4f | 1120 | |
f65eda4f SR |
1121 | p = pick_next_highest_task_rt(src_rq, this_cpu); |
1122 | ||
1123 | /* | |
1124 | * Do we have an RT task that preempts | |
1125 | * the to-be-scheduled task? | |
1126 | */ | |
1127 | if (p && (!next || (p->prio < next->prio))) { | |
1128 | WARN_ON(p == src_rq->curr); | |
1129 | WARN_ON(!p->se.on_rq); | |
1130 | ||
1131 | /* | |
1132 | * There's a chance that p is higher in priority | |
1133 | * than what's currently running on its cpu. | |
1134 | * This is just that p is wakeing up and hasn't | |
1135 | * had a chance to schedule. We only pull | |
1136 | * p if it is lower in priority than the | |
1137 | * current task on the run queue or | |
1138 | * this_rq next task is lower in prio than | |
1139 | * the current task on that rq. | |
1140 | */ | |
1141 | if (p->prio < src_rq->curr->prio || | |
1142 | (next && next->prio < src_rq->curr->prio)) | |
614ee1f6 | 1143 | goto skip; |
f65eda4f SR |
1144 | |
1145 | ret = 1; | |
1146 | ||
1147 | deactivate_task(src_rq, p, 0); | |
1148 | set_task_cpu(p, this_cpu); | |
1149 | activate_task(this_rq, p, 0); | |
1150 | /* | |
1151 | * We continue with the search, just in | |
1152 | * case there's an even higher prio task | |
1153 | * in another runqueue. (low likelyhood | |
1154 | * but possible) | |
80bf3171 | 1155 | * |
f65eda4f SR |
1156 | * Update next so that we won't pick a task |
1157 | * on another cpu with a priority lower (or equal) | |
1158 | * than the one we just picked. | |
1159 | */ | |
1160 | next = p; | |
1161 | ||
1162 | } | |
614ee1f6 | 1163 | skip: |
f65eda4f SR |
1164 | spin_unlock(&src_rq->lock); |
1165 | } | |
1166 | ||
1167 | return ret; | |
1168 | } | |
1169 | ||
9a897c5a | 1170 | static void pre_schedule_rt(struct rq *rq, struct task_struct *prev) |
f65eda4f SR |
1171 | { |
1172 | /* Try to pull RT tasks here if we lower this rq's prio */ | |
7f51f298 | 1173 | if (unlikely(rt_task(prev)) && rq->rt.highest_prio > prev->prio) |
f65eda4f SR |
1174 | pull_rt_task(rq); |
1175 | } | |
1176 | ||
9a897c5a | 1177 | static void post_schedule_rt(struct rq *rq) |
e8fa1362 SR |
1178 | { |
1179 | /* | |
1180 | * If we have more than one rt_task queued, then | |
1181 | * see if we can push the other rt_tasks off to other CPUS. | |
1182 | * Note we may release the rq lock, and since | |
1183 | * the lock was owned by prev, we need to release it | |
1184 | * first via finish_lock_switch and then reaquire it here. | |
1185 | */ | |
a22d7fc1 | 1186 | if (unlikely(rq->rt.overloaded)) { |
e8fa1362 SR |
1187 | spin_lock_irq(&rq->lock); |
1188 | push_rt_tasks(rq); | |
1189 | spin_unlock_irq(&rq->lock); | |
1190 | } | |
1191 | } | |
1192 | ||
8ae121ac GH |
1193 | /* |
1194 | * If we are not running and we are not going to reschedule soon, we should | |
1195 | * try to push tasks away now | |
1196 | */ | |
9a897c5a | 1197 | static void task_wake_up_rt(struct rq *rq, struct task_struct *p) |
4642dafd | 1198 | { |
9a897c5a | 1199 | if (!task_running(rq, p) && |
8ae121ac | 1200 | !test_tsk_need_resched(rq->curr) && |
a22d7fc1 | 1201 | rq->rt.overloaded) |
4642dafd SR |
1202 | push_rt_tasks(rq); |
1203 | } | |
1204 | ||
43010659 | 1205 | static unsigned long |
bb44e5d1 | 1206 | load_balance_rt(struct rq *this_rq, int this_cpu, struct rq *busiest, |
e1d1484f PW |
1207 | unsigned long max_load_move, |
1208 | struct sched_domain *sd, enum cpu_idle_type idle, | |
1209 | int *all_pinned, int *this_best_prio) | |
bb44e5d1 | 1210 | { |
c7a1e46a SR |
1211 | /* don't touch RT tasks */ |
1212 | return 0; | |
e1d1484f PW |
1213 | } |
1214 | ||
1215 | static int | |
1216 | move_one_task_rt(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
1217 | struct sched_domain *sd, enum cpu_idle_type idle) | |
1218 | { | |
c7a1e46a SR |
1219 | /* don't touch RT tasks */ |
1220 | return 0; | |
bb44e5d1 | 1221 | } |
deeeccd4 | 1222 | |
cd8ba7cd MT |
1223 | static void set_cpus_allowed_rt(struct task_struct *p, |
1224 | const cpumask_t *new_mask) | |
73fe6aae GH |
1225 | { |
1226 | int weight = cpus_weight(*new_mask); | |
1227 | ||
1228 | BUG_ON(!rt_task(p)); | |
1229 | ||
1230 | /* | |
1231 | * Update the migration status of the RQ if we have an RT task | |
1232 | * which is running AND changing its weight value. | |
1233 | */ | |
6f505b16 | 1234 | if (p->se.on_rq && (weight != p->rt.nr_cpus_allowed)) { |
73fe6aae GH |
1235 | struct rq *rq = task_rq(p); |
1236 | ||
6f505b16 | 1237 | if ((p->rt.nr_cpus_allowed <= 1) && (weight > 1)) { |
73fe6aae | 1238 | rq->rt.rt_nr_migratory++; |
6f505b16 | 1239 | } else if ((p->rt.nr_cpus_allowed > 1) && (weight <= 1)) { |
73fe6aae GH |
1240 | BUG_ON(!rq->rt.rt_nr_migratory); |
1241 | rq->rt.rt_nr_migratory--; | |
1242 | } | |
1243 | ||
1244 | update_rt_migration(rq); | |
1245 | } | |
1246 | ||
1247 | p->cpus_allowed = *new_mask; | |
6f505b16 | 1248 | p->rt.nr_cpus_allowed = weight; |
73fe6aae | 1249 | } |
deeeccd4 | 1250 | |
bdd7c81b | 1251 | /* Assumes rq->lock is held */ |
1f11eb6a | 1252 | static void rq_online_rt(struct rq *rq) |
bdd7c81b IM |
1253 | { |
1254 | if (rq->rt.overloaded) | |
1255 | rt_set_overload(rq); | |
6e0534f2 | 1256 | |
7def2be1 PZ |
1257 | __enable_runtime(rq); |
1258 | ||
6e0534f2 | 1259 | cpupri_set(&rq->rd->cpupri, rq->cpu, rq->rt.highest_prio); |
bdd7c81b IM |
1260 | } |
1261 | ||
1262 | /* Assumes rq->lock is held */ | |
1f11eb6a | 1263 | static void rq_offline_rt(struct rq *rq) |
bdd7c81b IM |
1264 | { |
1265 | if (rq->rt.overloaded) | |
1266 | rt_clear_overload(rq); | |
6e0534f2 | 1267 | |
7def2be1 PZ |
1268 | __disable_runtime(rq); |
1269 | ||
6e0534f2 | 1270 | cpupri_set(&rq->rd->cpupri, rq->cpu, CPUPRI_INVALID); |
bdd7c81b | 1271 | } |
cb469845 SR |
1272 | |
1273 | /* | |
1274 | * When switch from the rt queue, we bring ourselves to a position | |
1275 | * that we might want to pull RT tasks from other runqueues. | |
1276 | */ | |
1277 | static void switched_from_rt(struct rq *rq, struct task_struct *p, | |
1278 | int running) | |
1279 | { | |
1280 | /* | |
1281 | * If there are other RT tasks then we will reschedule | |
1282 | * and the scheduling of the other RT tasks will handle | |
1283 | * the balancing. But if we are the last RT task | |
1284 | * we may need to handle the pulling of RT tasks | |
1285 | * now. | |
1286 | */ | |
1287 | if (!rq->rt.rt_nr_running) | |
1288 | pull_rt_task(rq); | |
1289 | } | |
1290 | #endif /* CONFIG_SMP */ | |
1291 | ||
1292 | /* | |
1293 | * When switching a task to RT, we may overload the runqueue | |
1294 | * with RT tasks. In this case we try to push them off to | |
1295 | * other runqueues. | |
1296 | */ | |
1297 | static void switched_to_rt(struct rq *rq, struct task_struct *p, | |
1298 | int running) | |
1299 | { | |
1300 | int check_resched = 1; | |
1301 | ||
1302 | /* | |
1303 | * If we are already running, then there's nothing | |
1304 | * that needs to be done. But if we are not running | |
1305 | * we may need to preempt the current running task. | |
1306 | * If that current running task is also an RT task | |
1307 | * then see if we can move to another run queue. | |
1308 | */ | |
1309 | if (!running) { | |
1310 | #ifdef CONFIG_SMP | |
1311 | if (rq->rt.overloaded && push_rt_task(rq) && | |
1312 | /* Don't resched if we changed runqueues */ | |
1313 | rq != task_rq(p)) | |
1314 | check_resched = 0; | |
1315 | #endif /* CONFIG_SMP */ | |
1316 | if (check_resched && p->prio < rq->curr->prio) | |
1317 | resched_task(rq->curr); | |
1318 | } | |
1319 | } | |
1320 | ||
1321 | /* | |
1322 | * Priority of the task has changed. This may cause | |
1323 | * us to initiate a push or pull. | |
1324 | */ | |
1325 | static void prio_changed_rt(struct rq *rq, struct task_struct *p, | |
1326 | int oldprio, int running) | |
1327 | { | |
1328 | if (running) { | |
1329 | #ifdef CONFIG_SMP | |
1330 | /* | |
1331 | * If our priority decreases while running, we | |
1332 | * may need to pull tasks to this runqueue. | |
1333 | */ | |
1334 | if (oldprio < p->prio) | |
1335 | pull_rt_task(rq); | |
1336 | /* | |
1337 | * If there's a higher priority task waiting to run | |
6fa46fa5 SR |
1338 | * then reschedule. Note, the above pull_rt_task |
1339 | * can release the rq lock and p could migrate. | |
1340 | * Only reschedule if p is still on the same runqueue. | |
cb469845 | 1341 | */ |
6fa46fa5 | 1342 | if (p->prio > rq->rt.highest_prio && rq->curr == p) |
cb469845 SR |
1343 | resched_task(p); |
1344 | #else | |
1345 | /* For UP simply resched on drop of prio */ | |
1346 | if (oldprio < p->prio) | |
1347 | resched_task(p); | |
e8fa1362 | 1348 | #endif /* CONFIG_SMP */ |
cb469845 SR |
1349 | } else { |
1350 | /* | |
1351 | * This task is not running, but if it is | |
1352 | * greater than the current running task | |
1353 | * then reschedule. | |
1354 | */ | |
1355 | if (p->prio < rq->curr->prio) | |
1356 | resched_task(rq->curr); | |
1357 | } | |
1358 | } | |
1359 | ||
78f2c7db PZ |
1360 | static void watchdog(struct rq *rq, struct task_struct *p) |
1361 | { | |
1362 | unsigned long soft, hard; | |
1363 | ||
1364 | if (!p->signal) | |
1365 | return; | |
1366 | ||
1367 | soft = p->signal->rlim[RLIMIT_RTTIME].rlim_cur; | |
1368 | hard = p->signal->rlim[RLIMIT_RTTIME].rlim_max; | |
1369 | ||
1370 | if (soft != RLIM_INFINITY) { | |
1371 | unsigned long next; | |
1372 | ||
1373 | p->rt.timeout++; | |
1374 | next = DIV_ROUND_UP(min(soft, hard), USEC_PER_SEC/HZ); | |
5a52dd50 | 1375 | if (p->rt.timeout > next) |
78f2c7db PZ |
1376 | p->it_sched_expires = p->se.sum_exec_runtime; |
1377 | } | |
1378 | } | |
bb44e5d1 | 1379 | |
8f4d37ec | 1380 | static void task_tick_rt(struct rq *rq, struct task_struct *p, int queued) |
bb44e5d1 | 1381 | { |
67e2be02 PZ |
1382 | update_curr_rt(rq); |
1383 | ||
78f2c7db PZ |
1384 | watchdog(rq, p); |
1385 | ||
bb44e5d1 IM |
1386 | /* |
1387 | * RR tasks need a special form of timeslice management. | |
1388 | * FIFO tasks have no timeslices. | |
1389 | */ | |
1390 | if (p->policy != SCHED_RR) | |
1391 | return; | |
1392 | ||
fa717060 | 1393 | if (--p->rt.time_slice) |
bb44e5d1 IM |
1394 | return; |
1395 | ||
fa717060 | 1396 | p->rt.time_slice = DEF_TIMESLICE; |
bb44e5d1 | 1397 | |
98fbc798 DA |
1398 | /* |
1399 | * Requeue to the end of queue if we are not the only element | |
1400 | * on the queue: | |
1401 | */ | |
fa717060 | 1402 | if (p->rt.run_list.prev != p->rt.run_list.next) { |
98fbc798 DA |
1403 | requeue_task_rt(rq, p); |
1404 | set_tsk_need_resched(p); | |
1405 | } | |
bb44e5d1 IM |
1406 | } |
1407 | ||
83b699ed SV |
1408 | static void set_curr_task_rt(struct rq *rq) |
1409 | { | |
1410 | struct task_struct *p = rq->curr; | |
1411 | ||
1412 | p->se.exec_start = rq->clock; | |
1413 | } | |
1414 | ||
2abdad0a | 1415 | static const struct sched_class rt_sched_class = { |
5522d5d5 | 1416 | .next = &fair_sched_class, |
bb44e5d1 IM |
1417 | .enqueue_task = enqueue_task_rt, |
1418 | .dequeue_task = dequeue_task_rt, | |
1419 | .yield_task = yield_task_rt, | |
e7693a36 GH |
1420 | #ifdef CONFIG_SMP |
1421 | .select_task_rq = select_task_rq_rt, | |
1422 | #endif /* CONFIG_SMP */ | |
bb44e5d1 IM |
1423 | |
1424 | .check_preempt_curr = check_preempt_curr_rt, | |
1425 | ||
1426 | .pick_next_task = pick_next_task_rt, | |
1427 | .put_prev_task = put_prev_task_rt, | |
1428 | ||
681f3e68 | 1429 | #ifdef CONFIG_SMP |
bb44e5d1 | 1430 | .load_balance = load_balance_rt, |
e1d1484f | 1431 | .move_one_task = move_one_task_rt, |
73fe6aae | 1432 | .set_cpus_allowed = set_cpus_allowed_rt, |
1f11eb6a GH |
1433 | .rq_online = rq_online_rt, |
1434 | .rq_offline = rq_offline_rt, | |
9a897c5a SR |
1435 | .pre_schedule = pre_schedule_rt, |
1436 | .post_schedule = post_schedule_rt, | |
1437 | .task_wake_up = task_wake_up_rt, | |
cb469845 | 1438 | .switched_from = switched_from_rt, |
681f3e68 | 1439 | #endif |
bb44e5d1 | 1440 | |
83b699ed | 1441 | .set_curr_task = set_curr_task_rt, |
bb44e5d1 | 1442 | .task_tick = task_tick_rt, |
cb469845 SR |
1443 | |
1444 | .prio_changed = prio_changed_rt, | |
1445 | .switched_to = switched_to_rt, | |
bb44e5d1 | 1446 | }; |