Commit | Line | Data |
---|---|---|
bb44e5d1 IM |
1 | /* |
2 | * Real-Time Scheduling Class (mapped to the SCHED_FIFO and SCHED_RR | |
3 | * policies) | |
4 | */ | |
5 | ||
029632fb PZ |
6 | #include "sched.h" |
7 | ||
8 | #include <linux/slab.h> | |
b6366f04 | 9 | #include <linux/irq_work.h> |
029632fb | 10 | |
ce0dbbbb CW |
11 | int sched_rr_timeslice = RR_TIMESLICE; |
12 | ||
029632fb PZ |
13 | static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun); |
14 | ||
15 | struct rt_bandwidth def_rt_bandwidth; | |
16 | ||
17 | static enum hrtimer_restart sched_rt_period_timer(struct hrtimer *timer) | |
18 | { | |
19 | struct rt_bandwidth *rt_b = | |
20 | container_of(timer, struct rt_bandwidth, rt_period_timer); | |
029632fb | 21 | int idle = 0; |
77a4d1a1 | 22 | int overrun; |
029632fb | 23 | |
77a4d1a1 | 24 | raw_spin_lock(&rt_b->rt_runtime_lock); |
029632fb | 25 | for (;;) { |
77a4d1a1 | 26 | overrun = hrtimer_forward_now(timer, rt_b->rt_period); |
029632fb PZ |
27 | if (!overrun) |
28 | break; | |
29 | ||
77a4d1a1 | 30 | raw_spin_unlock(&rt_b->rt_runtime_lock); |
029632fb | 31 | idle = do_sched_rt_period_timer(rt_b, overrun); |
77a4d1a1 | 32 | raw_spin_lock(&rt_b->rt_runtime_lock); |
029632fb | 33 | } |
4cfafd30 PZ |
34 | if (idle) |
35 | rt_b->rt_period_active = 0; | |
77a4d1a1 | 36 | raw_spin_unlock(&rt_b->rt_runtime_lock); |
029632fb PZ |
37 | |
38 | return idle ? HRTIMER_NORESTART : HRTIMER_RESTART; | |
39 | } | |
40 | ||
41 | void init_rt_bandwidth(struct rt_bandwidth *rt_b, u64 period, u64 runtime) | |
42 | { | |
43 | rt_b->rt_period = ns_to_ktime(period); | |
44 | rt_b->rt_runtime = runtime; | |
45 | ||
46 | raw_spin_lock_init(&rt_b->rt_runtime_lock); | |
47 | ||
48 | hrtimer_init(&rt_b->rt_period_timer, | |
49 | CLOCK_MONOTONIC, HRTIMER_MODE_REL); | |
50 | rt_b->rt_period_timer.function = sched_rt_period_timer; | |
51 | } | |
52 | ||
53 | static void start_rt_bandwidth(struct rt_bandwidth *rt_b) | |
54 | { | |
55 | if (!rt_bandwidth_enabled() || rt_b->rt_runtime == RUNTIME_INF) | |
56 | return; | |
57 | ||
029632fb | 58 | raw_spin_lock(&rt_b->rt_runtime_lock); |
4cfafd30 PZ |
59 | if (!rt_b->rt_period_active) { |
60 | rt_b->rt_period_active = 1; | |
61 | hrtimer_forward_now(&rt_b->rt_period_timer, rt_b->rt_period); | |
62 | hrtimer_start_expires(&rt_b->rt_period_timer, HRTIMER_MODE_ABS_PINNED); | |
63 | } | |
029632fb PZ |
64 | raw_spin_unlock(&rt_b->rt_runtime_lock); |
65 | } | |
66 | ||
b6366f04 SR |
67 | #ifdef CONFIG_SMP |
68 | static void push_irq_work_func(struct irq_work *work); | |
69 | #endif | |
70 | ||
07c54f7a | 71 | void init_rt_rq(struct rt_rq *rt_rq) |
029632fb PZ |
72 | { |
73 | struct rt_prio_array *array; | |
74 | int i; | |
75 | ||
76 | array = &rt_rq->active; | |
77 | for (i = 0; i < MAX_RT_PRIO; i++) { | |
78 | INIT_LIST_HEAD(array->queue + i); | |
79 | __clear_bit(i, array->bitmap); | |
80 | } | |
81 | /* delimiter for bitsearch: */ | |
82 | __set_bit(MAX_RT_PRIO, array->bitmap); | |
83 | ||
84 | #if defined CONFIG_SMP | |
85 | rt_rq->highest_prio.curr = MAX_RT_PRIO; | |
86 | rt_rq->highest_prio.next = MAX_RT_PRIO; | |
87 | rt_rq->rt_nr_migratory = 0; | |
88 | rt_rq->overloaded = 0; | |
89 | plist_head_init(&rt_rq->pushable_tasks); | |
b6366f04 SR |
90 | |
91 | #ifdef HAVE_RT_PUSH_IPI | |
92 | rt_rq->push_flags = 0; | |
93 | rt_rq->push_cpu = nr_cpu_ids; | |
94 | raw_spin_lock_init(&rt_rq->push_lock); | |
95 | init_irq_work(&rt_rq->push_work, push_irq_work_func); | |
029632fb | 96 | #endif |
b6366f04 | 97 | #endif /* CONFIG_SMP */ |
f4ebcbc0 KT |
98 | /* We start is dequeued state, because no RT tasks are queued */ |
99 | rt_rq->rt_queued = 0; | |
029632fb PZ |
100 | |
101 | rt_rq->rt_time = 0; | |
102 | rt_rq->rt_throttled = 0; | |
103 | rt_rq->rt_runtime = 0; | |
104 | raw_spin_lock_init(&rt_rq->rt_runtime_lock); | |
105 | } | |
106 | ||
8f48894f | 107 | #ifdef CONFIG_RT_GROUP_SCHED |
029632fb PZ |
108 | static void destroy_rt_bandwidth(struct rt_bandwidth *rt_b) |
109 | { | |
110 | hrtimer_cancel(&rt_b->rt_period_timer); | |
111 | } | |
8f48894f PZ |
112 | |
113 | #define rt_entity_is_task(rt_se) (!(rt_se)->my_q) | |
114 | ||
398a153b GH |
115 | static inline struct task_struct *rt_task_of(struct sched_rt_entity *rt_se) |
116 | { | |
8f48894f PZ |
117 | #ifdef CONFIG_SCHED_DEBUG |
118 | WARN_ON_ONCE(!rt_entity_is_task(rt_se)); | |
119 | #endif | |
398a153b GH |
120 | return container_of(rt_se, struct task_struct, rt); |
121 | } | |
122 | ||
398a153b GH |
123 | static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq) |
124 | { | |
125 | return rt_rq->rq; | |
126 | } | |
127 | ||
128 | static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se) | |
129 | { | |
130 | return rt_se->rt_rq; | |
131 | } | |
132 | ||
653d07a6 KT |
133 | static inline struct rq *rq_of_rt_se(struct sched_rt_entity *rt_se) |
134 | { | |
135 | struct rt_rq *rt_rq = rt_se->rt_rq; | |
136 | ||
137 | return rt_rq->rq; | |
138 | } | |
139 | ||
029632fb PZ |
140 | void free_rt_sched_group(struct task_group *tg) |
141 | { | |
142 | int i; | |
143 | ||
144 | if (tg->rt_se) | |
145 | destroy_rt_bandwidth(&tg->rt_bandwidth); | |
146 | ||
147 | for_each_possible_cpu(i) { | |
148 | if (tg->rt_rq) | |
149 | kfree(tg->rt_rq[i]); | |
150 | if (tg->rt_se) | |
151 | kfree(tg->rt_se[i]); | |
152 | } | |
153 | ||
154 | kfree(tg->rt_rq); | |
155 | kfree(tg->rt_se); | |
156 | } | |
157 | ||
158 | void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq, | |
159 | struct sched_rt_entity *rt_se, int cpu, | |
160 | struct sched_rt_entity *parent) | |
161 | { | |
162 | struct rq *rq = cpu_rq(cpu); | |
163 | ||
164 | rt_rq->highest_prio.curr = MAX_RT_PRIO; | |
165 | rt_rq->rt_nr_boosted = 0; | |
166 | rt_rq->rq = rq; | |
167 | rt_rq->tg = tg; | |
168 | ||
169 | tg->rt_rq[cpu] = rt_rq; | |
170 | tg->rt_se[cpu] = rt_se; | |
171 | ||
172 | if (!rt_se) | |
173 | return; | |
174 | ||
175 | if (!parent) | |
176 | rt_se->rt_rq = &rq->rt; | |
177 | else | |
178 | rt_se->rt_rq = parent->my_q; | |
179 | ||
180 | rt_se->my_q = rt_rq; | |
181 | rt_se->parent = parent; | |
182 | INIT_LIST_HEAD(&rt_se->run_list); | |
183 | } | |
184 | ||
185 | int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent) | |
186 | { | |
187 | struct rt_rq *rt_rq; | |
188 | struct sched_rt_entity *rt_se; | |
189 | int i; | |
190 | ||
191 | tg->rt_rq = kzalloc(sizeof(rt_rq) * nr_cpu_ids, GFP_KERNEL); | |
192 | if (!tg->rt_rq) | |
193 | goto err; | |
194 | tg->rt_se = kzalloc(sizeof(rt_se) * nr_cpu_ids, GFP_KERNEL); | |
195 | if (!tg->rt_se) | |
196 | goto err; | |
197 | ||
198 | init_rt_bandwidth(&tg->rt_bandwidth, | |
199 | ktime_to_ns(def_rt_bandwidth.rt_period), 0); | |
200 | ||
201 | for_each_possible_cpu(i) { | |
202 | rt_rq = kzalloc_node(sizeof(struct rt_rq), | |
203 | GFP_KERNEL, cpu_to_node(i)); | |
204 | if (!rt_rq) | |
205 | goto err; | |
206 | ||
207 | rt_se = kzalloc_node(sizeof(struct sched_rt_entity), | |
208 | GFP_KERNEL, cpu_to_node(i)); | |
209 | if (!rt_se) | |
210 | goto err_free_rq; | |
211 | ||
07c54f7a | 212 | init_rt_rq(rt_rq); |
029632fb PZ |
213 | rt_rq->rt_runtime = tg->rt_bandwidth.rt_runtime; |
214 | init_tg_rt_entry(tg, rt_rq, rt_se, i, parent->rt_se[i]); | |
215 | } | |
216 | ||
217 | return 1; | |
218 | ||
219 | err_free_rq: | |
220 | kfree(rt_rq); | |
221 | err: | |
222 | return 0; | |
223 | } | |
224 | ||
398a153b GH |
225 | #else /* CONFIG_RT_GROUP_SCHED */ |
226 | ||
a1ba4d8b PZ |
227 | #define rt_entity_is_task(rt_se) (1) |
228 | ||
8f48894f PZ |
229 | static inline struct task_struct *rt_task_of(struct sched_rt_entity *rt_se) |
230 | { | |
231 | return container_of(rt_se, struct task_struct, rt); | |
232 | } | |
233 | ||
398a153b GH |
234 | static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq) |
235 | { | |
236 | return container_of(rt_rq, struct rq, rt); | |
237 | } | |
238 | ||
653d07a6 | 239 | static inline struct rq *rq_of_rt_se(struct sched_rt_entity *rt_se) |
398a153b GH |
240 | { |
241 | struct task_struct *p = rt_task_of(rt_se); | |
653d07a6 KT |
242 | |
243 | return task_rq(p); | |
244 | } | |
245 | ||
246 | static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se) | |
247 | { | |
248 | struct rq *rq = rq_of_rt_se(rt_se); | |
398a153b GH |
249 | |
250 | return &rq->rt; | |
251 | } | |
252 | ||
029632fb PZ |
253 | void free_rt_sched_group(struct task_group *tg) { } |
254 | ||
255 | int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent) | |
256 | { | |
257 | return 1; | |
258 | } | |
398a153b GH |
259 | #endif /* CONFIG_RT_GROUP_SCHED */ |
260 | ||
4fd29176 | 261 | #ifdef CONFIG_SMP |
84de4274 | 262 | |
38033c37 PZ |
263 | static int pull_rt_task(struct rq *this_rq); |
264 | ||
dc877341 PZ |
265 | static inline bool need_pull_rt_task(struct rq *rq, struct task_struct *prev) |
266 | { | |
267 | /* Try to pull RT tasks here if we lower this rq's prio */ | |
268 | return rq->rt.highest_prio.curr > prev->prio; | |
269 | } | |
270 | ||
637f5085 | 271 | static inline int rt_overloaded(struct rq *rq) |
4fd29176 | 272 | { |
637f5085 | 273 | return atomic_read(&rq->rd->rto_count); |
4fd29176 | 274 | } |
84de4274 | 275 | |
4fd29176 SR |
276 | static inline void rt_set_overload(struct rq *rq) |
277 | { | |
1f11eb6a GH |
278 | if (!rq->online) |
279 | return; | |
280 | ||
c6c4927b | 281 | cpumask_set_cpu(rq->cpu, rq->rd->rto_mask); |
4fd29176 SR |
282 | /* |
283 | * Make sure the mask is visible before we set | |
284 | * the overload count. That is checked to determine | |
285 | * if we should look at the mask. It would be a shame | |
286 | * if we looked at the mask, but the mask was not | |
287 | * updated yet. | |
7c3f2ab7 PZ |
288 | * |
289 | * Matched by the barrier in pull_rt_task(). | |
4fd29176 | 290 | */ |
7c3f2ab7 | 291 | smp_wmb(); |
637f5085 | 292 | atomic_inc(&rq->rd->rto_count); |
4fd29176 | 293 | } |
84de4274 | 294 | |
4fd29176 SR |
295 | static inline void rt_clear_overload(struct rq *rq) |
296 | { | |
1f11eb6a GH |
297 | if (!rq->online) |
298 | return; | |
299 | ||
4fd29176 | 300 | /* the order here really doesn't matter */ |
637f5085 | 301 | atomic_dec(&rq->rd->rto_count); |
c6c4927b | 302 | cpumask_clear_cpu(rq->cpu, rq->rd->rto_mask); |
4fd29176 | 303 | } |
73fe6aae | 304 | |
398a153b | 305 | static void update_rt_migration(struct rt_rq *rt_rq) |
73fe6aae | 306 | { |
a1ba4d8b | 307 | if (rt_rq->rt_nr_migratory && rt_rq->rt_nr_total > 1) { |
398a153b GH |
308 | if (!rt_rq->overloaded) { |
309 | rt_set_overload(rq_of_rt_rq(rt_rq)); | |
310 | rt_rq->overloaded = 1; | |
cdc8eb98 | 311 | } |
398a153b GH |
312 | } else if (rt_rq->overloaded) { |
313 | rt_clear_overload(rq_of_rt_rq(rt_rq)); | |
314 | rt_rq->overloaded = 0; | |
637f5085 | 315 | } |
73fe6aae | 316 | } |
4fd29176 | 317 | |
398a153b GH |
318 | static void inc_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) |
319 | { | |
29baa747 PZ |
320 | struct task_struct *p; |
321 | ||
a1ba4d8b PZ |
322 | if (!rt_entity_is_task(rt_se)) |
323 | return; | |
324 | ||
29baa747 | 325 | p = rt_task_of(rt_se); |
a1ba4d8b PZ |
326 | rt_rq = &rq_of_rt_rq(rt_rq)->rt; |
327 | ||
328 | rt_rq->rt_nr_total++; | |
29baa747 | 329 | if (p->nr_cpus_allowed > 1) |
398a153b GH |
330 | rt_rq->rt_nr_migratory++; |
331 | ||
332 | update_rt_migration(rt_rq); | |
333 | } | |
334 | ||
335 | static void dec_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) | |
336 | { | |
29baa747 PZ |
337 | struct task_struct *p; |
338 | ||
a1ba4d8b PZ |
339 | if (!rt_entity_is_task(rt_se)) |
340 | return; | |
341 | ||
29baa747 | 342 | p = rt_task_of(rt_se); |
a1ba4d8b PZ |
343 | rt_rq = &rq_of_rt_rq(rt_rq)->rt; |
344 | ||
345 | rt_rq->rt_nr_total--; | |
29baa747 | 346 | if (p->nr_cpus_allowed > 1) |
398a153b GH |
347 | rt_rq->rt_nr_migratory--; |
348 | ||
349 | update_rt_migration(rt_rq); | |
350 | } | |
351 | ||
5181f4a4 SR |
352 | static inline int has_pushable_tasks(struct rq *rq) |
353 | { | |
354 | return !plist_head_empty(&rq->rt.pushable_tasks); | |
355 | } | |
356 | ||
dc877341 PZ |
357 | static inline void set_post_schedule(struct rq *rq) |
358 | { | |
359 | /* | |
360 | * We detect this state here so that we can avoid taking the RQ | |
361 | * lock again later if there is no need to push | |
362 | */ | |
363 | rq->post_schedule = has_pushable_tasks(rq); | |
364 | } | |
365 | ||
917b627d GH |
366 | static void enqueue_pushable_task(struct rq *rq, struct task_struct *p) |
367 | { | |
368 | plist_del(&p->pushable_tasks, &rq->rt.pushable_tasks); | |
369 | plist_node_init(&p->pushable_tasks, p->prio); | |
370 | plist_add(&p->pushable_tasks, &rq->rt.pushable_tasks); | |
5181f4a4 SR |
371 | |
372 | /* Update the highest prio pushable task */ | |
373 | if (p->prio < rq->rt.highest_prio.next) | |
374 | rq->rt.highest_prio.next = p->prio; | |
917b627d GH |
375 | } |
376 | ||
377 | static void dequeue_pushable_task(struct rq *rq, struct task_struct *p) | |
378 | { | |
379 | plist_del(&p->pushable_tasks, &rq->rt.pushable_tasks); | |
917b627d | 380 | |
5181f4a4 SR |
381 | /* Update the new highest prio pushable task */ |
382 | if (has_pushable_tasks(rq)) { | |
383 | p = plist_first_entry(&rq->rt.pushable_tasks, | |
384 | struct task_struct, pushable_tasks); | |
385 | rq->rt.highest_prio.next = p->prio; | |
386 | } else | |
387 | rq->rt.highest_prio.next = MAX_RT_PRIO; | |
bcf08df3 IM |
388 | } |
389 | ||
917b627d GH |
390 | #else |
391 | ||
ceacc2c1 | 392 | static inline void enqueue_pushable_task(struct rq *rq, struct task_struct *p) |
fa85ae24 | 393 | { |
6f505b16 PZ |
394 | } |
395 | ||
ceacc2c1 PZ |
396 | static inline void dequeue_pushable_task(struct rq *rq, struct task_struct *p) |
397 | { | |
398 | } | |
399 | ||
b07430ac | 400 | static inline |
ceacc2c1 PZ |
401 | void inc_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) |
402 | { | |
403 | } | |
404 | ||
398a153b | 405 | static inline |
ceacc2c1 PZ |
406 | void dec_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) |
407 | { | |
408 | } | |
917b627d | 409 | |
dc877341 PZ |
410 | static inline bool need_pull_rt_task(struct rq *rq, struct task_struct *prev) |
411 | { | |
412 | return false; | |
413 | } | |
414 | ||
415 | static inline int pull_rt_task(struct rq *this_rq) | |
416 | { | |
417 | return 0; | |
418 | } | |
419 | ||
420 | static inline void set_post_schedule(struct rq *rq) | |
421 | { | |
422 | } | |
4fd29176 SR |
423 | #endif /* CONFIG_SMP */ |
424 | ||
f4ebcbc0 KT |
425 | static void enqueue_top_rt_rq(struct rt_rq *rt_rq); |
426 | static void dequeue_top_rt_rq(struct rt_rq *rt_rq); | |
427 | ||
6f505b16 PZ |
428 | static inline int on_rt_rq(struct sched_rt_entity *rt_se) |
429 | { | |
430 | return !list_empty(&rt_se->run_list); | |
431 | } | |
432 | ||
052f1dc7 | 433 | #ifdef CONFIG_RT_GROUP_SCHED |
6f505b16 | 434 | |
9f0c1e56 | 435 | static inline u64 sched_rt_runtime(struct rt_rq *rt_rq) |
6f505b16 PZ |
436 | { |
437 | if (!rt_rq->tg) | |
9f0c1e56 | 438 | return RUNTIME_INF; |
6f505b16 | 439 | |
ac086bc2 PZ |
440 | return rt_rq->rt_runtime; |
441 | } | |
442 | ||
443 | static inline u64 sched_rt_period(struct rt_rq *rt_rq) | |
444 | { | |
445 | return ktime_to_ns(rt_rq->tg->rt_bandwidth.rt_period); | |
6f505b16 PZ |
446 | } |
447 | ||
ec514c48 CX |
448 | typedef struct task_group *rt_rq_iter_t; |
449 | ||
1c09ab0d YZ |
450 | static inline struct task_group *next_task_group(struct task_group *tg) |
451 | { | |
452 | do { | |
453 | tg = list_entry_rcu(tg->list.next, | |
454 | typeof(struct task_group), list); | |
455 | } while (&tg->list != &task_groups && task_group_is_autogroup(tg)); | |
456 | ||
457 | if (&tg->list == &task_groups) | |
458 | tg = NULL; | |
459 | ||
460 | return tg; | |
461 | } | |
462 | ||
463 | #define for_each_rt_rq(rt_rq, iter, rq) \ | |
464 | for (iter = container_of(&task_groups, typeof(*iter), list); \ | |
465 | (iter = next_task_group(iter)) && \ | |
466 | (rt_rq = iter->rt_rq[cpu_of(rq)]);) | |
ec514c48 | 467 | |
6f505b16 PZ |
468 | #define for_each_sched_rt_entity(rt_se) \ |
469 | for (; rt_se; rt_se = rt_se->parent) | |
470 | ||
471 | static inline struct rt_rq *group_rt_rq(struct sched_rt_entity *rt_se) | |
472 | { | |
473 | return rt_se->my_q; | |
474 | } | |
475 | ||
37dad3fc | 476 | static void enqueue_rt_entity(struct sched_rt_entity *rt_se, bool head); |
6f505b16 PZ |
477 | static void dequeue_rt_entity(struct sched_rt_entity *rt_se); |
478 | ||
9f0c1e56 | 479 | static void sched_rt_rq_enqueue(struct rt_rq *rt_rq) |
6f505b16 | 480 | { |
f6121f4f | 481 | struct task_struct *curr = rq_of_rt_rq(rt_rq)->curr; |
8875125e | 482 | struct rq *rq = rq_of_rt_rq(rt_rq); |
74b7eb58 YZ |
483 | struct sched_rt_entity *rt_se; |
484 | ||
8875125e | 485 | int cpu = cpu_of(rq); |
0c3b9168 BS |
486 | |
487 | rt_se = rt_rq->tg->rt_se[cpu]; | |
6f505b16 | 488 | |
f6121f4f | 489 | if (rt_rq->rt_nr_running) { |
f4ebcbc0 KT |
490 | if (!rt_se) |
491 | enqueue_top_rt_rq(rt_rq); | |
492 | else if (!on_rt_rq(rt_se)) | |
37dad3fc | 493 | enqueue_rt_entity(rt_se, false); |
f4ebcbc0 | 494 | |
e864c499 | 495 | if (rt_rq->highest_prio.curr < curr->prio) |
8875125e | 496 | resched_curr(rq); |
6f505b16 PZ |
497 | } |
498 | } | |
499 | ||
9f0c1e56 | 500 | static void sched_rt_rq_dequeue(struct rt_rq *rt_rq) |
6f505b16 | 501 | { |
74b7eb58 | 502 | struct sched_rt_entity *rt_se; |
0c3b9168 | 503 | int cpu = cpu_of(rq_of_rt_rq(rt_rq)); |
74b7eb58 | 504 | |
0c3b9168 | 505 | rt_se = rt_rq->tg->rt_se[cpu]; |
6f505b16 | 506 | |
f4ebcbc0 KT |
507 | if (!rt_se) |
508 | dequeue_top_rt_rq(rt_rq); | |
509 | else if (on_rt_rq(rt_se)) | |
6f505b16 PZ |
510 | dequeue_rt_entity(rt_se); |
511 | } | |
512 | ||
46383648 KT |
513 | static inline int rt_rq_throttled(struct rt_rq *rt_rq) |
514 | { | |
515 | return rt_rq->rt_throttled && !rt_rq->rt_nr_boosted; | |
516 | } | |
517 | ||
23b0fdfc PZ |
518 | static int rt_se_boosted(struct sched_rt_entity *rt_se) |
519 | { | |
520 | struct rt_rq *rt_rq = group_rt_rq(rt_se); | |
521 | struct task_struct *p; | |
522 | ||
523 | if (rt_rq) | |
524 | return !!rt_rq->rt_nr_boosted; | |
525 | ||
526 | p = rt_task_of(rt_se); | |
527 | return p->prio != p->normal_prio; | |
528 | } | |
529 | ||
d0b27fa7 | 530 | #ifdef CONFIG_SMP |
c6c4927b | 531 | static inline const struct cpumask *sched_rt_period_mask(void) |
d0b27fa7 | 532 | { |
424c93fe | 533 | return this_rq()->rd->span; |
d0b27fa7 | 534 | } |
6f505b16 | 535 | #else |
c6c4927b | 536 | static inline const struct cpumask *sched_rt_period_mask(void) |
d0b27fa7 | 537 | { |
c6c4927b | 538 | return cpu_online_mask; |
d0b27fa7 PZ |
539 | } |
540 | #endif | |
6f505b16 | 541 | |
d0b27fa7 PZ |
542 | static inline |
543 | struct rt_rq *sched_rt_period_rt_rq(struct rt_bandwidth *rt_b, int cpu) | |
6f505b16 | 544 | { |
d0b27fa7 PZ |
545 | return container_of(rt_b, struct task_group, rt_bandwidth)->rt_rq[cpu]; |
546 | } | |
9f0c1e56 | 547 | |
ac086bc2 PZ |
548 | static inline struct rt_bandwidth *sched_rt_bandwidth(struct rt_rq *rt_rq) |
549 | { | |
550 | return &rt_rq->tg->rt_bandwidth; | |
551 | } | |
552 | ||
55e12e5e | 553 | #else /* !CONFIG_RT_GROUP_SCHED */ |
d0b27fa7 PZ |
554 | |
555 | static inline u64 sched_rt_runtime(struct rt_rq *rt_rq) | |
556 | { | |
ac086bc2 PZ |
557 | return rt_rq->rt_runtime; |
558 | } | |
559 | ||
560 | static inline u64 sched_rt_period(struct rt_rq *rt_rq) | |
561 | { | |
562 | return ktime_to_ns(def_rt_bandwidth.rt_period); | |
6f505b16 PZ |
563 | } |
564 | ||
ec514c48 CX |
565 | typedef struct rt_rq *rt_rq_iter_t; |
566 | ||
567 | #define for_each_rt_rq(rt_rq, iter, rq) \ | |
568 | for ((void) iter, rt_rq = &rq->rt; rt_rq; rt_rq = NULL) | |
569 | ||
6f505b16 PZ |
570 | #define for_each_sched_rt_entity(rt_se) \ |
571 | for (; rt_se; rt_se = NULL) | |
572 | ||
573 | static inline struct rt_rq *group_rt_rq(struct sched_rt_entity *rt_se) | |
574 | { | |
575 | return NULL; | |
576 | } | |
577 | ||
9f0c1e56 | 578 | static inline void sched_rt_rq_enqueue(struct rt_rq *rt_rq) |
6f505b16 | 579 | { |
f4ebcbc0 KT |
580 | struct rq *rq = rq_of_rt_rq(rt_rq); |
581 | ||
582 | if (!rt_rq->rt_nr_running) | |
583 | return; | |
584 | ||
585 | enqueue_top_rt_rq(rt_rq); | |
8875125e | 586 | resched_curr(rq); |
6f505b16 PZ |
587 | } |
588 | ||
9f0c1e56 | 589 | static inline void sched_rt_rq_dequeue(struct rt_rq *rt_rq) |
6f505b16 | 590 | { |
f4ebcbc0 | 591 | dequeue_top_rt_rq(rt_rq); |
6f505b16 PZ |
592 | } |
593 | ||
46383648 KT |
594 | static inline int rt_rq_throttled(struct rt_rq *rt_rq) |
595 | { | |
596 | return rt_rq->rt_throttled; | |
597 | } | |
598 | ||
c6c4927b | 599 | static inline const struct cpumask *sched_rt_period_mask(void) |
d0b27fa7 | 600 | { |
c6c4927b | 601 | return cpu_online_mask; |
d0b27fa7 PZ |
602 | } |
603 | ||
604 | static inline | |
605 | struct rt_rq *sched_rt_period_rt_rq(struct rt_bandwidth *rt_b, int cpu) | |
606 | { | |
607 | return &cpu_rq(cpu)->rt; | |
608 | } | |
609 | ||
ac086bc2 PZ |
610 | static inline struct rt_bandwidth *sched_rt_bandwidth(struct rt_rq *rt_rq) |
611 | { | |
612 | return &def_rt_bandwidth; | |
613 | } | |
614 | ||
55e12e5e | 615 | #endif /* CONFIG_RT_GROUP_SCHED */ |
d0b27fa7 | 616 | |
faa59937 JL |
617 | bool sched_rt_bandwidth_account(struct rt_rq *rt_rq) |
618 | { | |
619 | struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq); | |
620 | ||
621 | return (hrtimer_active(&rt_b->rt_period_timer) || | |
622 | rt_rq->rt_time < rt_b->rt_runtime); | |
623 | } | |
624 | ||
ac086bc2 | 625 | #ifdef CONFIG_SMP |
78333cdd PZ |
626 | /* |
627 | * We ran out of runtime, see if we can borrow some from our neighbours. | |
628 | */ | |
b79f3833 | 629 | static int do_balance_runtime(struct rt_rq *rt_rq) |
ac086bc2 PZ |
630 | { |
631 | struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq); | |
aa7f6730 | 632 | struct root_domain *rd = rq_of_rt_rq(rt_rq)->rd; |
ac086bc2 PZ |
633 | int i, weight, more = 0; |
634 | u64 rt_period; | |
635 | ||
c6c4927b | 636 | weight = cpumask_weight(rd->span); |
ac086bc2 | 637 | |
0986b11b | 638 | raw_spin_lock(&rt_b->rt_runtime_lock); |
ac086bc2 | 639 | rt_period = ktime_to_ns(rt_b->rt_period); |
c6c4927b | 640 | for_each_cpu(i, rd->span) { |
ac086bc2 PZ |
641 | struct rt_rq *iter = sched_rt_period_rt_rq(rt_b, i); |
642 | s64 diff; | |
643 | ||
644 | if (iter == rt_rq) | |
645 | continue; | |
646 | ||
0986b11b | 647 | raw_spin_lock(&iter->rt_runtime_lock); |
78333cdd PZ |
648 | /* |
649 | * Either all rqs have inf runtime and there's nothing to steal | |
650 | * or __disable_runtime() below sets a specific rq to inf to | |
651 | * indicate its been disabled and disalow stealing. | |
652 | */ | |
7def2be1 PZ |
653 | if (iter->rt_runtime == RUNTIME_INF) |
654 | goto next; | |
655 | ||
78333cdd PZ |
656 | /* |
657 | * From runqueues with spare time, take 1/n part of their | |
658 | * spare time, but no more than our period. | |
659 | */ | |
ac086bc2 PZ |
660 | diff = iter->rt_runtime - iter->rt_time; |
661 | if (diff > 0) { | |
58838cf3 | 662 | diff = div_u64((u64)diff, weight); |
ac086bc2 PZ |
663 | if (rt_rq->rt_runtime + diff > rt_period) |
664 | diff = rt_period - rt_rq->rt_runtime; | |
665 | iter->rt_runtime -= diff; | |
666 | rt_rq->rt_runtime += diff; | |
667 | more = 1; | |
668 | if (rt_rq->rt_runtime == rt_period) { | |
0986b11b | 669 | raw_spin_unlock(&iter->rt_runtime_lock); |
ac086bc2 PZ |
670 | break; |
671 | } | |
672 | } | |
7def2be1 | 673 | next: |
0986b11b | 674 | raw_spin_unlock(&iter->rt_runtime_lock); |
ac086bc2 | 675 | } |
0986b11b | 676 | raw_spin_unlock(&rt_b->rt_runtime_lock); |
ac086bc2 PZ |
677 | |
678 | return more; | |
679 | } | |
7def2be1 | 680 | |
78333cdd PZ |
681 | /* |
682 | * Ensure this RQ takes back all the runtime it lend to its neighbours. | |
683 | */ | |
7def2be1 PZ |
684 | static void __disable_runtime(struct rq *rq) |
685 | { | |
686 | struct root_domain *rd = rq->rd; | |
ec514c48 | 687 | rt_rq_iter_t iter; |
7def2be1 PZ |
688 | struct rt_rq *rt_rq; |
689 | ||
690 | if (unlikely(!scheduler_running)) | |
691 | return; | |
692 | ||
ec514c48 | 693 | for_each_rt_rq(rt_rq, iter, rq) { |
7def2be1 PZ |
694 | struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq); |
695 | s64 want; | |
696 | int i; | |
697 | ||
0986b11b TG |
698 | raw_spin_lock(&rt_b->rt_runtime_lock); |
699 | raw_spin_lock(&rt_rq->rt_runtime_lock); | |
78333cdd PZ |
700 | /* |
701 | * Either we're all inf and nobody needs to borrow, or we're | |
702 | * already disabled and thus have nothing to do, or we have | |
703 | * exactly the right amount of runtime to take out. | |
704 | */ | |
7def2be1 PZ |
705 | if (rt_rq->rt_runtime == RUNTIME_INF || |
706 | rt_rq->rt_runtime == rt_b->rt_runtime) | |
707 | goto balanced; | |
0986b11b | 708 | raw_spin_unlock(&rt_rq->rt_runtime_lock); |
7def2be1 | 709 | |
78333cdd PZ |
710 | /* |
711 | * Calculate the difference between what we started out with | |
712 | * and what we current have, that's the amount of runtime | |
713 | * we lend and now have to reclaim. | |
714 | */ | |
7def2be1 PZ |
715 | want = rt_b->rt_runtime - rt_rq->rt_runtime; |
716 | ||
78333cdd PZ |
717 | /* |
718 | * Greedy reclaim, take back as much as we can. | |
719 | */ | |
c6c4927b | 720 | for_each_cpu(i, rd->span) { |
7def2be1 PZ |
721 | struct rt_rq *iter = sched_rt_period_rt_rq(rt_b, i); |
722 | s64 diff; | |
723 | ||
78333cdd PZ |
724 | /* |
725 | * Can't reclaim from ourselves or disabled runqueues. | |
726 | */ | |
f1679d08 | 727 | if (iter == rt_rq || iter->rt_runtime == RUNTIME_INF) |
7def2be1 PZ |
728 | continue; |
729 | ||
0986b11b | 730 | raw_spin_lock(&iter->rt_runtime_lock); |
7def2be1 PZ |
731 | if (want > 0) { |
732 | diff = min_t(s64, iter->rt_runtime, want); | |
733 | iter->rt_runtime -= diff; | |
734 | want -= diff; | |
735 | } else { | |
736 | iter->rt_runtime -= want; | |
737 | want -= want; | |
738 | } | |
0986b11b | 739 | raw_spin_unlock(&iter->rt_runtime_lock); |
7def2be1 PZ |
740 | |
741 | if (!want) | |
742 | break; | |
743 | } | |
744 | ||
0986b11b | 745 | raw_spin_lock(&rt_rq->rt_runtime_lock); |
78333cdd PZ |
746 | /* |
747 | * We cannot be left wanting - that would mean some runtime | |
748 | * leaked out of the system. | |
749 | */ | |
7def2be1 PZ |
750 | BUG_ON(want); |
751 | balanced: | |
78333cdd PZ |
752 | /* |
753 | * Disable all the borrow logic by pretending we have inf | |
754 | * runtime - in which case borrowing doesn't make sense. | |
755 | */ | |
7def2be1 | 756 | rt_rq->rt_runtime = RUNTIME_INF; |
a4c96ae3 | 757 | rt_rq->rt_throttled = 0; |
0986b11b TG |
758 | raw_spin_unlock(&rt_rq->rt_runtime_lock); |
759 | raw_spin_unlock(&rt_b->rt_runtime_lock); | |
99b62567 KT |
760 | |
761 | /* Make rt_rq available for pick_next_task() */ | |
762 | sched_rt_rq_enqueue(rt_rq); | |
7def2be1 PZ |
763 | } |
764 | } | |
765 | ||
7def2be1 PZ |
766 | static void __enable_runtime(struct rq *rq) |
767 | { | |
ec514c48 | 768 | rt_rq_iter_t iter; |
7def2be1 PZ |
769 | struct rt_rq *rt_rq; |
770 | ||
771 | if (unlikely(!scheduler_running)) | |
772 | return; | |
773 | ||
78333cdd PZ |
774 | /* |
775 | * Reset each runqueue's bandwidth settings | |
776 | */ | |
ec514c48 | 777 | for_each_rt_rq(rt_rq, iter, rq) { |
7def2be1 PZ |
778 | struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq); |
779 | ||
0986b11b TG |
780 | raw_spin_lock(&rt_b->rt_runtime_lock); |
781 | raw_spin_lock(&rt_rq->rt_runtime_lock); | |
7def2be1 PZ |
782 | rt_rq->rt_runtime = rt_b->rt_runtime; |
783 | rt_rq->rt_time = 0; | |
baf25731 | 784 | rt_rq->rt_throttled = 0; |
0986b11b TG |
785 | raw_spin_unlock(&rt_rq->rt_runtime_lock); |
786 | raw_spin_unlock(&rt_b->rt_runtime_lock); | |
7def2be1 PZ |
787 | } |
788 | } | |
789 | ||
eff6549b PZ |
790 | static int balance_runtime(struct rt_rq *rt_rq) |
791 | { | |
792 | int more = 0; | |
793 | ||
4a6184ce PZ |
794 | if (!sched_feat(RT_RUNTIME_SHARE)) |
795 | return more; | |
796 | ||
eff6549b | 797 | if (rt_rq->rt_time > rt_rq->rt_runtime) { |
0986b11b | 798 | raw_spin_unlock(&rt_rq->rt_runtime_lock); |
eff6549b | 799 | more = do_balance_runtime(rt_rq); |
0986b11b | 800 | raw_spin_lock(&rt_rq->rt_runtime_lock); |
eff6549b PZ |
801 | } |
802 | ||
803 | return more; | |
804 | } | |
55e12e5e | 805 | #else /* !CONFIG_SMP */ |
eff6549b PZ |
806 | static inline int balance_runtime(struct rt_rq *rt_rq) |
807 | { | |
808 | return 0; | |
809 | } | |
55e12e5e | 810 | #endif /* CONFIG_SMP */ |
ac086bc2 | 811 | |
eff6549b PZ |
812 | static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun) |
813 | { | |
42c62a58 | 814 | int i, idle = 1, throttled = 0; |
c6c4927b | 815 | const struct cpumask *span; |
eff6549b | 816 | |
eff6549b | 817 | span = sched_rt_period_mask(); |
e221d028 MG |
818 | #ifdef CONFIG_RT_GROUP_SCHED |
819 | /* | |
820 | * FIXME: isolated CPUs should really leave the root task group, | |
821 | * whether they are isolcpus or were isolated via cpusets, lest | |
822 | * the timer run on a CPU which does not service all runqueues, | |
823 | * potentially leaving other CPUs indefinitely throttled. If | |
824 | * isolation is really required, the user will turn the throttle | |
825 | * off to kill the perturbations it causes anyway. Meanwhile, | |
826 | * this maintains functionality for boot and/or troubleshooting. | |
827 | */ | |
828 | if (rt_b == &root_task_group.rt_bandwidth) | |
829 | span = cpu_online_mask; | |
830 | #endif | |
c6c4927b | 831 | for_each_cpu(i, span) { |
eff6549b PZ |
832 | int enqueue = 0; |
833 | struct rt_rq *rt_rq = sched_rt_period_rt_rq(rt_b, i); | |
834 | struct rq *rq = rq_of_rt_rq(rt_rq); | |
835 | ||
05fa785c | 836 | raw_spin_lock(&rq->lock); |
eff6549b PZ |
837 | if (rt_rq->rt_time) { |
838 | u64 runtime; | |
839 | ||
0986b11b | 840 | raw_spin_lock(&rt_rq->rt_runtime_lock); |
eff6549b PZ |
841 | if (rt_rq->rt_throttled) |
842 | balance_runtime(rt_rq); | |
843 | runtime = rt_rq->rt_runtime; | |
844 | rt_rq->rt_time -= min(rt_rq->rt_time, overrun*runtime); | |
845 | if (rt_rq->rt_throttled && rt_rq->rt_time < runtime) { | |
846 | rt_rq->rt_throttled = 0; | |
847 | enqueue = 1; | |
61eadef6 MG |
848 | |
849 | /* | |
9edfbfed PZ |
850 | * When we're idle and a woken (rt) task is |
851 | * throttled check_preempt_curr() will set | |
852 | * skip_update and the time between the wakeup | |
853 | * and this unthrottle will get accounted as | |
854 | * 'runtime'. | |
61eadef6 MG |
855 | */ |
856 | if (rt_rq->rt_nr_running && rq->curr == rq->idle) | |
9edfbfed | 857 | rq_clock_skip_update(rq, false); |
eff6549b PZ |
858 | } |
859 | if (rt_rq->rt_time || rt_rq->rt_nr_running) | |
860 | idle = 0; | |
0986b11b | 861 | raw_spin_unlock(&rt_rq->rt_runtime_lock); |
0c3b9168 | 862 | } else if (rt_rq->rt_nr_running) { |
6c3df255 | 863 | idle = 0; |
0c3b9168 BS |
864 | if (!rt_rq_throttled(rt_rq)) |
865 | enqueue = 1; | |
866 | } | |
42c62a58 PZ |
867 | if (rt_rq->rt_throttled) |
868 | throttled = 1; | |
eff6549b PZ |
869 | |
870 | if (enqueue) | |
871 | sched_rt_rq_enqueue(rt_rq); | |
05fa785c | 872 | raw_spin_unlock(&rq->lock); |
eff6549b PZ |
873 | } |
874 | ||
42c62a58 PZ |
875 | if (!throttled && (!rt_bandwidth_enabled() || rt_b->rt_runtime == RUNTIME_INF)) |
876 | return 1; | |
877 | ||
eff6549b PZ |
878 | return idle; |
879 | } | |
ac086bc2 | 880 | |
6f505b16 PZ |
881 | static inline int rt_se_prio(struct sched_rt_entity *rt_se) |
882 | { | |
052f1dc7 | 883 | #ifdef CONFIG_RT_GROUP_SCHED |
6f505b16 PZ |
884 | struct rt_rq *rt_rq = group_rt_rq(rt_se); |
885 | ||
886 | if (rt_rq) | |
e864c499 | 887 | return rt_rq->highest_prio.curr; |
6f505b16 PZ |
888 | #endif |
889 | ||
890 | return rt_task_of(rt_se)->prio; | |
891 | } | |
892 | ||
9f0c1e56 | 893 | static int sched_rt_runtime_exceeded(struct rt_rq *rt_rq) |
6f505b16 | 894 | { |
9f0c1e56 | 895 | u64 runtime = sched_rt_runtime(rt_rq); |
fa85ae24 | 896 | |
fa85ae24 | 897 | if (rt_rq->rt_throttled) |
23b0fdfc | 898 | return rt_rq_throttled(rt_rq); |
fa85ae24 | 899 | |
5b680fd6 | 900 | if (runtime >= sched_rt_period(rt_rq)) |
ac086bc2 PZ |
901 | return 0; |
902 | ||
b79f3833 PZ |
903 | balance_runtime(rt_rq); |
904 | runtime = sched_rt_runtime(rt_rq); | |
905 | if (runtime == RUNTIME_INF) | |
906 | return 0; | |
ac086bc2 | 907 | |
9f0c1e56 | 908 | if (rt_rq->rt_time > runtime) { |
7abc63b1 PZ |
909 | struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq); |
910 | ||
911 | /* | |
912 | * Don't actually throttle groups that have no runtime assigned | |
913 | * but accrue some time due to boosting. | |
914 | */ | |
915 | if (likely(rt_b->rt_runtime)) { | |
916 | rt_rq->rt_throttled = 1; | |
c224815d | 917 | printk_deferred_once("sched: RT throttling activated\n"); |
7abc63b1 PZ |
918 | } else { |
919 | /* | |
920 | * In case we did anyway, make it go away, | |
921 | * replenishment is a joke, since it will replenish us | |
922 | * with exactly 0 ns. | |
923 | */ | |
924 | rt_rq->rt_time = 0; | |
925 | } | |
926 | ||
23b0fdfc | 927 | if (rt_rq_throttled(rt_rq)) { |
9f0c1e56 | 928 | sched_rt_rq_dequeue(rt_rq); |
23b0fdfc PZ |
929 | return 1; |
930 | } | |
fa85ae24 PZ |
931 | } |
932 | ||
933 | return 0; | |
934 | } | |
935 | ||
bb44e5d1 IM |
936 | /* |
937 | * Update the current task's runtime statistics. Skip current tasks that | |
938 | * are not in our scheduling class. | |
939 | */ | |
a9957449 | 940 | static void update_curr_rt(struct rq *rq) |
bb44e5d1 IM |
941 | { |
942 | struct task_struct *curr = rq->curr; | |
6f505b16 | 943 | struct sched_rt_entity *rt_se = &curr->rt; |
bb44e5d1 IM |
944 | u64 delta_exec; |
945 | ||
06c3bc65 | 946 | if (curr->sched_class != &rt_sched_class) |
bb44e5d1 IM |
947 | return; |
948 | ||
78becc27 | 949 | delta_exec = rq_clock_task(rq) - curr->se.exec_start; |
fc79e240 KT |
950 | if (unlikely((s64)delta_exec <= 0)) |
951 | return; | |
6cfb0d5d | 952 | |
42c62a58 PZ |
953 | schedstat_set(curr->se.statistics.exec_max, |
954 | max(curr->se.statistics.exec_max, delta_exec)); | |
bb44e5d1 IM |
955 | |
956 | curr->se.sum_exec_runtime += delta_exec; | |
f06febc9 FM |
957 | account_group_exec_runtime(curr, delta_exec); |
958 | ||
78becc27 | 959 | curr->se.exec_start = rq_clock_task(rq); |
d842de87 | 960 | cpuacct_charge(curr, delta_exec); |
fa85ae24 | 961 | |
e9e9250b PZ |
962 | sched_rt_avg_update(rq, delta_exec); |
963 | ||
0b148fa0 PZ |
964 | if (!rt_bandwidth_enabled()) |
965 | return; | |
966 | ||
354d60c2 | 967 | for_each_sched_rt_entity(rt_se) { |
0b07939c | 968 | struct rt_rq *rt_rq = rt_rq_of_se(rt_se); |
354d60c2 | 969 | |
cc2991cf | 970 | if (sched_rt_runtime(rt_rq) != RUNTIME_INF) { |
0986b11b | 971 | raw_spin_lock(&rt_rq->rt_runtime_lock); |
cc2991cf PZ |
972 | rt_rq->rt_time += delta_exec; |
973 | if (sched_rt_runtime_exceeded(rt_rq)) | |
8875125e | 974 | resched_curr(rq); |
0986b11b | 975 | raw_spin_unlock(&rt_rq->rt_runtime_lock); |
cc2991cf | 976 | } |
354d60c2 | 977 | } |
bb44e5d1 IM |
978 | } |
979 | ||
f4ebcbc0 KT |
980 | static void |
981 | dequeue_top_rt_rq(struct rt_rq *rt_rq) | |
982 | { | |
983 | struct rq *rq = rq_of_rt_rq(rt_rq); | |
984 | ||
985 | BUG_ON(&rq->rt != rt_rq); | |
986 | ||
987 | if (!rt_rq->rt_queued) | |
988 | return; | |
989 | ||
990 | BUG_ON(!rq->nr_running); | |
991 | ||
72465447 | 992 | sub_nr_running(rq, rt_rq->rt_nr_running); |
f4ebcbc0 KT |
993 | rt_rq->rt_queued = 0; |
994 | } | |
995 | ||
996 | static void | |
997 | enqueue_top_rt_rq(struct rt_rq *rt_rq) | |
998 | { | |
999 | struct rq *rq = rq_of_rt_rq(rt_rq); | |
1000 | ||
1001 | BUG_ON(&rq->rt != rt_rq); | |
1002 | ||
1003 | if (rt_rq->rt_queued) | |
1004 | return; | |
1005 | if (rt_rq_throttled(rt_rq) || !rt_rq->rt_nr_running) | |
1006 | return; | |
1007 | ||
72465447 | 1008 | add_nr_running(rq, rt_rq->rt_nr_running); |
f4ebcbc0 KT |
1009 | rt_rq->rt_queued = 1; |
1010 | } | |
1011 | ||
398a153b | 1012 | #if defined CONFIG_SMP |
e864c499 | 1013 | |
398a153b GH |
1014 | static void |
1015 | inc_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio) | |
63489e45 | 1016 | { |
4d984277 | 1017 | struct rq *rq = rq_of_rt_rq(rt_rq); |
1f11eb6a | 1018 | |
757dfcaa KT |
1019 | #ifdef CONFIG_RT_GROUP_SCHED |
1020 | /* | |
1021 | * Change rq's cpupri only if rt_rq is the top queue. | |
1022 | */ | |
1023 | if (&rq->rt != rt_rq) | |
1024 | return; | |
1025 | #endif | |
5181f4a4 SR |
1026 | if (rq->online && prio < prev_prio) |
1027 | cpupri_set(&rq->rd->cpupri, rq->cpu, prio); | |
398a153b | 1028 | } |
73fe6aae | 1029 | |
398a153b GH |
1030 | static void |
1031 | dec_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio) | |
1032 | { | |
1033 | struct rq *rq = rq_of_rt_rq(rt_rq); | |
d0b27fa7 | 1034 | |
757dfcaa KT |
1035 | #ifdef CONFIG_RT_GROUP_SCHED |
1036 | /* | |
1037 | * Change rq's cpupri only if rt_rq is the top queue. | |
1038 | */ | |
1039 | if (&rq->rt != rt_rq) | |
1040 | return; | |
1041 | #endif | |
398a153b GH |
1042 | if (rq->online && rt_rq->highest_prio.curr != prev_prio) |
1043 | cpupri_set(&rq->rd->cpupri, rq->cpu, rt_rq->highest_prio.curr); | |
63489e45 SR |
1044 | } |
1045 | ||
398a153b GH |
1046 | #else /* CONFIG_SMP */ |
1047 | ||
6f505b16 | 1048 | static inline |
398a153b GH |
1049 | void inc_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio) {} |
1050 | static inline | |
1051 | void dec_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio) {} | |
1052 | ||
1053 | #endif /* CONFIG_SMP */ | |
6e0534f2 | 1054 | |
052f1dc7 | 1055 | #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED |
398a153b GH |
1056 | static void |
1057 | inc_rt_prio(struct rt_rq *rt_rq, int prio) | |
1058 | { | |
1059 | int prev_prio = rt_rq->highest_prio.curr; | |
1060 | ||
1061 | if (prio < prev_prio) | |
1062 | rt_rq->highest_prio.curr = prio; | |
1063 | ||
1064 | inc_rt_prio_smp(rt_rq, prio, prev_prio); | |
1065 | } | |
1066 | ||
1067 | static void | |
1068 | dec_rt_prio(struct rt_rq *rt_rq, int prio) | |
1069 | { | |
1070 | int prev_prio = rt_rq->highest_prio.curr; | |
1071 | ||
6f505b16 | 1072 | if (rt_rq->rt_nr_running) { |
764a9d6f | 1073 | |
398a153b | 1074 | WARN_ON(prio < prev_prio); |
764a9d6f | 1075 | |
e864c499 | 1076 | /* |
398a153b GH |
1077 | * This may have been our highest task, and therefore |
1078 | * we may have some recomputation to do | |
e864c499 | 1079 | */ |
398a153b | 1080 | if (prio == prev_prio) { |
e864c499 GH |
1081 | struct rt_prio_array *array = &rt_rq->active; |
1082 | ||
1083 | rt_rq->highest_prio.curr = | |
764a9d6f | 1084 | sched_find_first_bit(array->bitmap); |
e864c499 GH |
1085 | } |
1086 | ||
764a9d6f | 1087 | } else |
e864c499 | 1088 | rt_rq->highest_prio.curr = MAX_RT_PRIO; |
73fe6aae | 1089 | |
398a153b GH |
1090 | dec_rt_prio_smp(rt_rq, prio, prev_prio); |
1091 | } | |
1f11eb6a | 1092 | |
398a153b GH |
1093 | #else |
1094 | ||
1095 | static inline void inc_rt_prio(struct rt_rq *rt_rq, int prio) {} | |
1096 | static inline void dec_rt_prio(struct rt_rq *rt_rq, int prio) {} | |
1097 | ||
1098 | #endif /* CONFIG_SMP || CONFIG_RT_GROUP_SCHED */ | |
6e0534f2 | 1099 | |
052f1dc7 | 1100 | #ifdef CONFIG_RT_GROUP_SCHED |
398a153b GH |
1101 | |
1102 | static void | |
1103 | inc_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) | |
1104 | { | |
1105 | if (rt_se_boosted(rt_se)) | |
1106 | rt_rq->rt_nr_boosted++; | |
1107 | ||
1108 | if (rt_rq->tg) | |
1109 | start_rt_bandwidth(&rt_rq->tg->rt_bandwidth); | |
1110 | } | |
1111 | ||
1112 | static void | |
1113 | dec_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) | |
1114 | { | |
23b0fdfc PZ |
1115 | if (rt_se_boosted(rt_se)) |
1116 | rt_rq->rt_nr_boosted--; | |
1117 | ||
1118 | WARN_ON(!rt_rq->rt_nr_running && rt_rq->rt_nr_boosted); | |
398a153b GH |
1119 | } |
1120 | ||
1121 | #else /* CONFIG_RT_GROUP_SCHED */ | |
1122 | ||
1123 | static void | |
1124 | inc_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) | |
1125 | { | |
1126 | start_rt_bandwidth(&def_rt_bandwidth); | |
1127 | } | |
1128 | ||
1129 | static inline | |
1130 | void dec_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) {} | |
1131 | ||
1132 | #endif /* CONFIG_RT_GROUP_SCHED */ | |
1133 | ||
22abdef3 KT |
1134 | static inline |
1135 | unsigned int rt_se_nr_running(struct sched_rt_entity *rt_se) | |
1136 | { | |
1137 | struct rt_rq *group_rq = group_rt_rq(rt_se); | |
1138 | ||
1139 | if (group_rq) | |
1140 | return group_rq->rt_nr_running; | |
1141 | else | |
1142 | return 1; | |
1143 | } | |
1144 | ||
398a153b GH |
1145 | static inline |
1146 | void inc_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) | |
1147 | { | |
1148 | int prio = rt_se_prio(rt_se); | |
1149 | ||
1150 | WARN_ON(!rt_prio(prio)); | |
22abdef3 | 1151 | rt_rq->rt_nr_running += rt_se_nr_running(rt_se); |
398a153b GH |
1152 | |
1153 | inc_rt_prio(rt_rq, prio); | |
1154 | inc_rt_migration(rt_se, rt_rq); | |
1155 | inc_rt_group(rt_se, rt_rq); | |
1156 | } | |
1157 | ||
1158 | static inline | |
1159 | void dec_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) | |
1160 | { | |
1161 | WARN_ON(!rt_prio(rt_se_prio(rt_se))); | |
1162 | WARN_ON(!rt_rq->rt_nr_running); | |
22abdef3 | 1163 | rt_rq->rt_nr_running -= rt_se_nr_running(rt_se); |
398a153b GH |
1164 | |
1165 | dec_rt_prio(rt_rq, rt_se_prio(rt_se)); | |
1166 | dec_rt_migration(rt_se, rt_rq); | |
1167 | dec_rt_group(rt_se, rt_rq); | |
63489e45 SR |
1168 | } |
1169 | ||
37dad3fc | 1170 | static void __enqueue_rt_entity(struct sched_rt_entity *rt_se, bool head) |
bb44e5d1 | 1171 | { |
6f505b16 PZ |
1172 | struct rt_rq *rt_rq = rt_rq_of_se(rt_se); |
1173 | struct rt_prio_array *array = &rt_rq->active; | |
1174 | struct rt_rq *group_rq = group_rt_rq(rt_se); | |
20b6331b | 1175 | struct list_head *queue = array->queue + rt_se_prio(rt_se); |
bb44e5d1 | 1176 | |
ad2a3f13 PZ |
1177 | /* |
1178 | * Don't enqueue the group if its throttled, or when empty. | |
1179 | * The latter is a consequence of the former when a child group | |
1180 | * get throttled and the current group doesn't have any other | |
1181 | * active members. | |
1182 | */ | |
1183 | if (group_rq && (rt_rq_throttled(group_rq) || !group_rq->rt_nr_running)) | |
6f505b16 | 1184 | return; |
63489e45 | 1185 | |
37dad3fc TG |
1186 | if (head) |
1187 | list_add(&rt_se->run_list, queue); | |
1188 | else | |
1189 | list_add_tail(&rt_se->run_list, queue); | |
6f505b16 | 1190 | __set_bit(rt_se_prio(rt_se), array->bitmap); |
78f2c7db | 1191 | |
6f505b16 PZ |
1192 | inc_rt_tasks(rt_se, rt_rq); |
1193 | } | |
1194 | ||
ad2a3f13 | 1195 | static void __dequeue_rt_entity(struct sched_rt_entity *rt_se) |
6f505b16 PZ |
1196 | { |
1197 | struct rt_rq *rt_rq = rt_rq_of_se(rt_se); | |
1198 | struct rt_prio_array *array = &rt_rq->active; | |
1199 | ||
1200 | list_del_init(&rt_se->run_list); | |
1201 | if (list_empty(array->queue + rt_se_prio(rt_se))) | |
1202 | __clear_bit(rt_se_prio(rt_se), array->bitmap); | |
1203 | ||
1204 | dec_rt_tasks(rt_se, rt_rq); | |
1205 | } | |
1206 | ||
1207 | /* | |
1208 | * Because the prio of an upper entry depends on the lower | |
1209 | * entries, we must remove entries top - down. | |
6f505b16 | 1210 | */ |
ad2a3f13 | 1211 | static void dequeue_rt_stack(struct sched_rt_entity *rt_se) |
6f505b16 | 1212 | { |
ad2a3f13 | 1213 | struct sched_rt_entity *back = NULL; |
6f505b16 | 1214 | |
58d6c2d7 PZ |
1215 | for_each_sched_rt_entity(rt_se) { |
1216 | rt_se->back = back; | |
1217 | back = rt_se; | |
1218 | } | |
1219 | ||
f4ebcbc0 KT |
1220 | dequeue_top_rt_rq(rt_rq_of_se(back)); |
1221 | ||
58d6c2d7 PZ |
1222 | for (rt_se = back; rt_se; rt_se = rt_se->back) { |
1223 | if (on_rt_rq(rt_se)) | |
ad2a3f13 PZ |
1224 | __dequeue_rt_entity(rt_se); |
1225 | } | |
1226 | } | |
1227 | ||
37dad3fc | 1228 | static void enqueue_rt_entity(struct sched_rt_entity *rt_se, bool head) |
ad2a3f13 | 1229 | { |
f4ebcbc0 KT |
1230 | struct rq *rq = rq_of_rt_se(rt_se); |
1231 | ||
ad2a3f13 PZ |
1232 | dequeue_rt_stack(rt_se); |
1233 | for_each_sched_rt_entity(rt_se) | |
37dad3fc | 1234 | __enqueue_rt_entity(rt_se, head); |
f4ebcbc0 | 1235 | enqueue_top_rt_rq(&rq->rt); |
ad2a3f13 PZ |
1236 | } |
1237 | ||
1238 | static void dequeue_rt_entity(struct sched_rt_entity *rt_se) | |
1239 | { | |
f4ebcbc0 KT |
1240 | struct rq *rq = rq_of_rt_se(rt_se); |
1241 | ||
ad2a3f13 PZ |
1242 | dequeue_rt_stack(rt_se); |
1243 | ||
1244 | for_each_sched_rt_entity(rt_se) { | |
1245 | struct rt_rq *rt_rq = group_rt_rq(rt_se); | |
1246 | ||
1247 | if (rt_rq && rt_rq->rt_nr_running) | |
37dad3fc | 1248 | __enqueue_rt_entity(rt_se, false); |
58d6c2d7 | 1249 | } |
f4ebcbc0 | 1250 | enqueue_top_rt_rq(&rq->rt); |
bb44e5d1 IM |
1251 | } |
1252 | ||
1253 | /* | |
1254 | * Adding/removing a task to/from a priority array: | |
1255 | */ | |
ea87bb78 | 1256 | static void |
371fd7e7 | 1257 | enqueue_task_rt(struct rq *rq, struct task_struct *p, int flags) |
6f505b16 PZ |
1258 | { |
1259 | struct sched_rt_entity *rt_se = &p->rt; | |
1260 | ||
371fd7e7 | 1261 | if (flags & ENQUEUE_WAKEUP) |
6f505b16 PZ |
1262 | rt_se->timeout = 0; |
1263 | ||
371fd7e7 | 1264 | enqueue_rt_entity(rt_se, flags & ENQUEUE_HEAD); |
c09595f6 | 1265 | |
29baa747 | 1266 | if (!task_current(rq, p) && p->nr_cpus_allowed > 1) |
917b627d | 1267 | enqueue_pushable_task(rq, p); |
6f505b16 PZ |
1268 | } |
1269 | ||
371fd7e7 | 1270 | static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int flags) |
bb44e5d1 | 1271 | { |
6f505b16 | 1272 | struct sched_rt_entity *rt_se = &p->rt; |
bb44e5d1 | 1273 | |
f1e14ef6 | 1274 | update_curr_rt(rq); |
ad2a3f13 | 1275 | dequeue_rt_entity(rt_se); |
c09595f6 | 1276 | |
917b627d | 1277 | dequeue_pushable_task(rq, p); |
bb44e5d1 IM |
1278 | } |
1279 | ||
1280 | /* | |
60686317 RW |
1281 | * Put task to the head or the end of the run list without the overhead of |
1282 | * dequeue followed by enqueue. | |
bb44e5d1 | 1283 | */ |
7ebefa8c DA |
1284 | static void |
1285 | requeue_rt_entity(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se, int head) | |
6f505b16 | 1286 | { |
1cdad715 | 1287 | if (on_rt_rq(rt_se)) { |
7ebefa8c DA |
1288 | struct rt_prio_array *array = &rt_rq->active; |
1289 | struct list_head *queue = array->queue + rt_se_prio(rt_se); | |
1290 | ||
1291 | if (head) | |
1292 | list_move(&rt_se->run_list, queue); | |
1293 | else | |
1294 | list_move_tail(&rt_se->run_list, queue); | |
1cdad715 | 1295 | } |
6f505b16 PZ |
1296 | } |
1297 | ||
7ebefa8c | 1298 | static void requeue_task_rt(struct rq *rq, struct task_struct *p, int head) |
bb44e5d1 | 1299 | { |
6f505b16 PZ |
1300 | struct sched_rt_entity *rt_se = &p->rt; |
1301 | struct rt_rq *rt_rq; | |
bb44e5d1 | 1302 | |
6f505b16 PZ |
1303 | for_each_sched_rt_entity(rt_se) { |
1304 | rt_rq = rt_rq_of_se(rt_se); | |
7ebefa8c | 1305 | requeue_rt_entity(rt_rq, rt_se, head); |
6f505b16 | 1306 | } |
bb44e5d1 IM |
1307 | } |
1308 | ||
6f505b16 | 1309 | static void yield_task_rt(struct rq *rq) |
bb44e5d1 | 1310 | { |
7ebefa8c | 1311 | requeue_task_rt(rq, rq->curr, 0); |
bb44e5d1 IM |
1312 | } |
1313 | ||
e7693a36 | 1314 | #ifdef CONFIG_SMP |
318e0893 GH |
1315 | static int find_lowest_rq(struct task_struct *task); |
1316 | ||
0017d735 | 1317 | static int |
ac66f547 | 1318 | select_task_rq_rt(struct task_struct *p, int cpu, int sd_flag, int flags) |
e7693a36 | 1319 | { |
7608dec2 PZ |
1320 | struct task_struct *curr; |
1321 | struct rq *rq; | |
c37495fd SR |
1322 | |
1323 | /* For anything but wake ups, just return the task_cpu */ | |
1324 | if (sd_flag != SD_BALANCE_WAKE && sd_flag != SD_BALANCE_FORK) | |
1325 | goto out; | |
1326 | ||
7608dec2 PZ |
1327 | rq = cpu_rq(cpu); |
1328 | ||
1329 | rcu_read_lock(); | |
316c1608 | 1330 | curr = READ_ONCE(rq->curr); /* unlocked access */ |
7608dec2 | 1331 | |
318e0893 | 1332 | /* |
7608dec2 | 1333 | * If the current task on @p's runqueue is an RT task, then |
e1f47d89 SR |
1334 | * try to see if we can wake this RT task up on another |
1335 | * runqueue. Otherwise simply start this RT task | |
1336 | * on its current runqueue. | |
1337 | * | |
43fa5460 SR |
1338 | * We want to avoid overloading runqueues. If the woken |
1339 | * task is a higher priority, then it will stay on this CPU | |
1340 | * and the lower prio task should be moved to another CPU. | |
1341 | * Even though this will probably make the lower prio task | |
1342 | * lose its cache, we do not want to bounce a higher task | |
1343 | * around just because it gave up its CPU, perhaps for a | |
1344 | * lock? | |
1345 | * | |
1346 | * For equal prio tasks, we just let the scheduler sort it out. | |
7608dec2 PZ |
1347 | * |
1348 | * Otherwise, just let it ride on the affined RQ and the | |
1349 | * post-schedule router will push the preempted task away | |
1350 | * | |
1351 | * This test is optimistic, if we get it wrong the load-balancer | |
1352 | * will have to sort it out. | |
318e0893 | 1353 | */ |
7608dec2 | 1354 | if (curr && unlikely(rt_task(curr)) && |
29baa747 | 1355 | (curr->nr_cpus_allowed < 2 || |
6bfa687c | 1356 | curr->prio <= p->prio)) { |
7608dec2 | 1357 | int target = find_lowest_rq(p); |
318e0893 | 1358 | |
80e3d87b TC |
1359 | /* |
1360 | * Don't bother moving it if the destination CPU is | |
1361 | * not running a lower priority task. | |
1362 | */ | |
1363 | if (target != -1 && | |
1364 | p->prio < cpu_rq(target)->rt.highest_prio.curr) | |
7608dec2 | 1365 | cpu = target; |
318e0893 | 1366 | } |
7608dec2 | 1367 | rcu_read_unlock(); |
318e0893 | 1368 | |
c37495fd | 1369 | out: |
7608dec2 | 1370 | return cpu; |
e7693a36 | 1371 | } |
7ebefa8c DA |
1372 | |
1373 | static void check_preempt_equal_prio(struct rq *rq, struct task_struct *p) | |
1374 | { | |
308a623a WL |
1375 | /* |
1376 | * Current can't be migrated, useless to reschedule, | |
1377 | * let's hope p can move out. | |
1378 | */ | |
1379 | if (rq->curr->nr_cpus_allowed == 1 || | |
1380 | !cpupri_find(&rq->rd->cpupri, rq->curr, NULL)) | |
7ebefa8c DA |
1381 | return; |
1382 | ||
308a623a WL |
1383 | /* |
1384 | * p is migratable, so let's not schedule it and | |
1385 | * see if it is pushed or pulled somewhere else. | |
1386 | */ | |
29baa747 | 1387 | if (p->nr_cpus_allowed != 1 |
13b8bd0a RR |
1388 | && cpupri_find(&rq->rd->cpupri, p, NULL)) |
1389 | return; | |
24600ce8 | 1390 | |
7ebefa8c DA |
1391 | /* |
1392 | * There appears to be other cpus that can accept | |
1393 | * current and none to run 'p', so lets reschedule | |
1394 | * to try and push current away: | |
1395 | */ | |
1396 | requeue_task_rt(rq, p, 1); | |
8875125e | 1397 | resched_curr(rq); |
7ebefa8c DA |
1398 | } |
1399 | ||
e7693a36 GH |
1400 | #endif /* CONFIG_SMP */ |
1401 | ||
bb44e5d1 IM |
1402 | /* |
1403 | * Preempt the current task with a newly woken task if needed: | |
1404 | */ | |
7d478721 | 1405 | static void check_preempt_curr_rt(struct rq *rq, struct task_struct *p, int flags) |
bb44e5d1 | 1406 | { |
45c01e82 | 1407 | if (p->prio < rq->curr->prio) { |
8875125e | 1408 | resched_curr(rq); |
45c01e82 GH |
1409 | return; |
1410 | } | |
1411 | ||
1412 | #ifdef CONFIG_SMP | |
1413 | /* | |
1414 | * If: | |
1415 | * | |
1416 | * - the newly woken task is of equal priority to the current task | |
1417 | * - the newly woken task is non-migratable while current is migratable | |
1418 | * - current will be preempted on the next reschedule | |
1419 | * | |
1420 | * we should check to see if current can readily move to a different | |
1421 | * cpu. If so, we will reschedule to allow the push logic to try | |
1422 | * to move current somewhere else, making room for our non-migratable | |
1423 | * task. | |
1424 | */ | |
8dd0de8b | 1425 | if (p->prio == rq->curr->prio && !test_tsk_need_resched(rq->curr)) |
7ebefa8c | 1426 | check_preempt_equal_prio(rq, p); |
45c01e82 | 1427 | #endif |
bb44e5d1 IM |
1428 | } |
1429 | ||
6f505b16 PZ |
1430 | static struct sched_rt_entity *pick_next_rt_entity(struct rq *rq, |
1431 | struct rt_rq *rt_rq) | |
bb44e5d1 | 1432 | { |
6f505b16 PZ |
1433 | struct rt_prio_array *array = &rt_rq->active; |
1434 | struct sched_rt_entity *next = NULL; | |
bb44e5d1 IM |
1435 | struct list_head *queue; |
1436 | int idx; | |
1437 | ||
1438 | idx = sched_find_first_bit(array->bitmap); | |
6f505b16 | 1439 | BUG_ON(idx >= MAX_RT_PRIO); |
bb44e5d1 IM |
1440 | |
1441 | queue = array->queue + idx; | |
6f505b16 | 1442 | next = list_entry(queue->next, struct sched_rt_entity, run_list); |
326587b8 | 1443 | |
6f505b16 PZ |
1444 | return next; |
1445 | } | |
bb44e5d1 | 1446 | |
917b627d | 1447 | static struct task_struct *_pick_next_task_rt(struct rq *rq) |
6f505b16 PZ |
1448 | { |
1449 | struct sched_rt_entity *rt_se; | |
1450 | struct task_struct *p; | |
606dba2e | 1451 | struct rt_rq *rt_rq = &rq->rt; |
6f505b16 PZ |
1452 | |
1453 | do { | |
1454 | rt_se = pick_next_rt_entity(rq, rt_rq); | |
326587b8 | 1455 | BUG_ON(!rt_se); |
6f505b16 PZ |
1456 | rt_rq = group_rt_rq(rt_se); |
1457 | } while (rt_rq); | |
1458 | ||
1459 | p = rt_task_of(rt_se); | |
78becc27 | 1460 | p->se.exec_start = rq_clock_task(rq); |
917b627d GH |
1461 | |
1462 | return p; | |
1463 | } | |
1464 | ||
606dba2e PZ |
1465 | static struct task_struct * |
1466 | pick_next_task_rt(struct rq *rq, struct task_struct *prev) | |
917b627d | 1467 | { |
606dba2e PZ |
1468 | struct task_struct *p; |
1469 | struct rt_rq *rt_rq = &rq->rt; | |
1470 | ||
37e117c0 | 1471 | if (need_pull_rt_task(rq, prev)) { |
38033c37 | 1472 | pull_rt_task(rq); |
37e117c0 PZ |
1473 | /* |
1474 | * pull_rt_task() can drop (and re-acquire) rq->lock; this | |
a1d9a323 KT |
1475 | * means a dl or stop task can slip in, in which case we need |
1476 | * to re-start task selection. | |
37e117c0 | 1477 | */ |
da0c1e65 | 1478 | if (unlikely((rq->stop && task_on_rq_queued(rq->stop)) || |
a1d9a323 | 1479 | rq->dl.dl_nr_running)) |
37e117c0 PZ |
1480 | return RETRY_TASK; |
1481 | } | |
38033c37 | 1482 | |
734ff2a7 KT |
1483 | /* |
1484 | * We may dequeue prev's rt_rq in put_prev_task(). | |
1485 | * So, we update time before rt_nr_running check. | |
1486 | */ | |
1487 | if (prev->sched_class == &rt_sched_class) | |
1488 | update_curr_rt(rq); | |
1489 | ||
f4ebcbc0 | 1490 | if (!rt_rq->rt_queued) |
606dba2e PZ |
1491 | return NULL; |
1492 | ||
3f1d2a31 | 1493 | put_prev_task(rq, prev); |
606dba2e PZ |
1494 | |
1495 | p = _pick_next_task_rt(rq); | |
917b627d GH |
1496 | |
1497 | /* The running task is never eligible for pushing */ | |
f3f1768f | 1498 | dequeue_pushable_task(rq, p); |
917b627d | 1499 | |
dc877341 | 1500 | set_post_schedule(rq); |
3f029d3c | 1501 | |
6f505b16 | 1502 | return p; |
bb44e5d1 IM |
1503 | } |
1504 | ||
31ee529c | 1505 | static void put_prev_task_rt(struct rq *rq, struct task_struct *p) |
bb44e5d1 | 1506 | { |
f1e14ef6 | 1507 | update_curr_rt(rq); |
917b627d GH |
1508 | |
1509 | /* | |
1510 | * The previous task needs to be made eligible for pushing | |
1511 | * if it is still active | |
1512 | */ | |
29baa747 | 1513 | if (on_rt_rq(&p->rt) && p->nr_cpus_allowed > 1) |
917b627d | 1514 | enqueue_pushable_task(rq, p); |
bb44e5d1 IM |
1515 | } |
1516 | ||
681f3e68 | 1517 | #ifdef CONFIG_SMP |
6f505b16 | 1518 | |
e8fa1362 SR |
1519 | /* Only try algorithms three times */ |
1520 | #define RT_MAX_TRIES 3 | |
1521 | ||
f65eda4f SR |
1522 | static int pick_rt_task(struct rq *rq, struct task_struct *p, int cpu) |
1523 | { | |
1524 | if (!task_running(rq, p) && | |
60334caf | 1525 | cpumask_test_cpu(cpu, tsk_cpus_allowed(p))) |
f65eda4f SR |
1526 | return 1; |
1527 | return 0; | |
1528 | } | |
1529 | ||
e23ee747 KT |
1530 | /* |
1531 | * Return the highest pushable rq's task, which is suitable to be executed | |
1532 | * on the cpu, NULL otherwise | |
1533 | */ | |
1534 | static struct task_struct *pick_highest_pushable_task(struct rq *rq, int cpu) | |
e8fa1362 | 1535 | { |
e23ee747 KT |
1536 | struct plist_head *head = &rq->rt.pushable_tasks; |
1537 | struct task_struct *p; | |
3d07467b | 1538 | |
e23ee747 KT |
1539 | if (!has_pushable_tasks(rq)) |
1540 | return NULL; | |
3d07467b | 1541 | |
e23ee747 KT |
1542 | plist_for_each_entry(p, head, pushable_tasks) { |
1543 | if (pick_rt_task(rq, p, cpu)) | |
1544 | return p; | |
f65eda4f SR |
1545 | } |
1546 | ||
e23ee747 | 1547 | return NULL; |
e8fa1362 SR |
1548 | } |
1549 | ||
0e3900e6 | 1550 | static DEFINE_PER_CPU(cpumask_var_t, local_cpu_mask); |
e8fa1362 | 1551 | |
6e1254d2 GH |
1552 | static int find_lowest_rq(struct task_struct *task) |
1553 | { | |
1554 | struct sched_domain *sd; | |
4ba29684 | 1555 | struct cpumask *lowest_mask = this_cpu_cpumask_var_ptr(local_cpu_mask); |
6e1254d2 GH |
1556 | int this_cpu = smp_processor_id(); |
1557 | int cpu = task_cpu(task); | |
06f90dbd | 1558 | |
0da938c4 SR |
1559 | /* Make sure the mask is initialized first */ |
1560 | if (unlikely(!lowest_mask)) | |
1561 | return -1; | |
1562 | ||
29baa747 | 1563 | if (task->nr_cpus_allowed == 1) |
6e0534f2 | 1564 | return -1; /* No other targets possible */ |
6e1254d2 | 1565 | |
6e0534f2 GH |
1566 | if (!cpupri_find(&task_rq(task)->rd->cpupri, task, lowest_mask)) |
1567 | return -1; /* No targets found */ | |
6e1254d2 GH |
1568 | |
1569 | /* | |
1570 | * At this point we have built a mask of cpus representing the | |
1571 | * lowest priority tasks in the system. Now we want to elect | |
1572 | * the best one based on our affinity and topology. | |
1573 | * | |
1574 | * We prioritize the last cpu that the task executed on since | |
1575 | * it is most likely cache-hot in that location. | |
1576 | */ | |
96f874e2 | 1577 | if (cpumask_test_cpu(cpu, lowest_mask)) |
6e1254d2 GH |
1578 | return cpu; |
1579 | ||
1580 | /* | |
1581 | * Otherwise, we consult the sched_domains span maps to figure | |
1582 | * out which cpu is logically closest to our hot cache data. | |
1583 | */ | |
e2c88063 RR |
1584 | if (!cpumask_test_cpu(this_cpu, lowest_mask)) |
1585 | this_cpu = -1; /* Skip this_cpu opt if not among lowest */ | |
6e1254d2 | 1586 | |
cd4ae6ad | 1587 | rcu_read_lock(); |
e2c88063 RR |
1588 | for_each_domain(cpu, sd) { |
1589 | if (sd->flags & SD_WAKE_AFFINE) { | |
1590 | int best_cpu; | |
6e1254d2 | 1591 | |
e2c88063 RR |
1592 | /* |
1593 | * "this_cpu" is cheaper to preempt than a | |
1594 | * remote processor. | |
1595 | */ | |
1596 | if (this_cpu != -1 && | |
cd4ae6ad XF |
1597 | cpumask_test_cpu(this_cpu, sched_domain_span(sd))) { |
1598 | rcu_read_unlock(); | |
e2c88063 | 1599 | return this_cpu; |
cd4ae6ad | 1600 | } |
e2c88063 RR |
1601 | |
1602 | best_cpu = cpumask_first_and(lowest_mask, | |
1603 | sched_domain_span(sd)); | |
cd4ae6ad XF |
1604 | if (best_cpu < nr_cpu_ids) { |
1605 | rcu_read_unlock(); | |
e2c88063 | 1606 | return best_cpu; |
cd4ae6ad | 1607 | } |
6e1254d2 GH |
1608 | } |
1609 | } | |
cd4ae6ad | 1610 | rcu_read_unlock(); |
6e1254d2 GH |
1611 | |
1612 | /* | |
1613 | * And finally, if there were no matches within the domains | |
1614 | * just give the caller *something* to work with from the compatible | |
1615 | * locations. | |
1616 | */ | |
e2c88063 RR |
1617 | if (this_cpu != -1) |
1618 | return this_cpu; | |
1619 | ||
1620 | cpu = cpumask_any(lowest_mask); | |
1621 | if (cpu < nr_cpu_ids) | |
1622 | return cpu; | |
1623 | return -1; | |
07b4032c GH |
1624 | } |
1625 | ||
1626 | /* Will lock the rq it finds */ | |
4df64c0b | 1627 | static struct rq *find_lock_lowest_rq(struct task_struct *task, struct rq *rq) |
07b4032c GH |
1628 | { |
1629 | struct rq *lowest_rq = NULL; | |
07b4032c | 1630 | int tries; |
4df64c0b | 1631 | int cpu; |
e8fa1362 | 1632 | |
07b4032c GH |
1633 | for (tries = 0; tries < RT_MAX_TRIES; tries++) { |
1634 | cpu = find_lowest_rq(task); | |
1635 | ||
2de0b463 | 1636 | if ((cpu == -1) || (cpu == rq->cpu)) |
e8fa1362 SR |
1637 | break; |
1638 | ||
07b4032c GH |
1639 | lowest_rq = cpu_rq(cpu); |
1640 | ||
80e3d87b TC |
1641 | if (lowest_rq->rt.highest_prio.curr <= task->prio) { |
1642 | /* | |
1643 | * Target rq has tasks of equal or higher priority, | |
1644 | * retrying does not release any lock and is unlikely | |
1645 | * to yield a different result. | |
1646 | */ | |
1647 | lowest_rq = NULL; | |
1648 | break; | |
1649 | } | |
1650 | ||
e8fa1362 | 1651 | /* if the prio of this runqueue changed, try again */ |
07b4032c | 1652 | if (double_lock_balance(rq, lowest_rq)) { |
e8fa1362 SR |
1653 | /* |
1654 | * We had to unlock the run queue. In | |
1655 | * the mean time, task could have | |
1656 | * migrated already or had its affinity changed. | |
1657 | * Also make sure that it wasn't scheduled on its rq. | |
1658 | */ | |
07b4032c | 1659 | if (unlikely(task_rq(task) != rq || |
96f874e2 | 1660 | !cpumask_test_cpu(lowest_rq->cpu, |
fa17b507 | 1661 | tsk_cpus_allowed(task)) || |
07b4032c | 1662 | task_running(rq, task) || |
da0c1e65 | 1663 | !task_on_rq_queued(task))) { |
4df64c0b | 1664 | |
7f1b4393 | 1665 | double_unlock_balance(rq, lowest_rq); |
e8fa1362 SR |
1666 | lowest_rq = NULL; |
1667 | break; | |
1668 | } | |
1669 | } | |
1670 | ||
1671 | /* If this rq is still suitable use it. */ | |
e864c499 | 1672 | if (lowest_rq->rt.highest_prio.curr > task->prio) |
e8fa1362 SR |
1673 | break; |
1674 | ||
1675 | /* try again */ | |
1b12bbc7 | 1676 | double_unlock_balance(rq, lowest_rq); |
e8fa1362 SR |
1677 | lowest_rq = NULL; |
1678 | } | |
1679 | ||
1680 | return lowest_rq; | |
1681 | } | |
1682 | ||
917b627d GH |
1683 | static struct task_struct *pick_next_pushable_task(struct rq *rq) |
1684 | { | |
1685 | struct task_struct *p; | |
1686 | ||
1687 | if (!has_pushable_tasks(rq)) | |
1688 | return NULL; | |
1689 | ||
1690 | p = plist_first_entry(&rq->rt.pushable_tasks, | |
1691 | struct task_struct, pushable_tasks); | |
1692 | ||
1693 | BUG_ON(rq->cpu != task_cpu(p)); | |
1694 | BUG_ON(task_current(rq, p)); | |
29baa747 | 1695 | BUG_ON(p->nr_cpus_allowed <= 1); |
917b627d | 1696 | |
da0c1e65 | 1697 | BUG_ON(!task_on_rq_queued(p)); |
917b627d GH |
1698 | BUG_ON(!rt_task(p)); |
1699 | ||
1700 | return p; | |
1701 | } | |
1702 | ||
e8fa1362 SR |
1703 | /* |
1704 | * If the current CPU has more than one RT task, see if the non | |
1705 | * running task can migrate over to a CPU that is running a task | |
1706 | * of lesser priority. | |
1707 | */ | |
697f0a48 | 1708 | static int push_rt_task(struct rq *rq) |
e8fa1362 SR |
1709 | { |
1710 | struct task_struct *next_task; | |
1711 | struct rq *lowest_rq; | |
311e800e | 1712 | int ret = 0; |
e8fa1362 | 1713 | |
a22d7fc1 GH |
1714 | if (!rq->rt.overloaded) |
1715 | return 0; | |
1716 | ||
917b627d | 1717 | next_task = pick_next_pushable_task(rq); |
e8fa1362 SR |
1718 | if (!next_task) |
1719 | return 0; | |
1720 | ||
49246274 | 1721 | retry: |
697f0a48 | 1722 | if (unlikely(next_task == rq->curr)) { |
f65eda4f | 1723 | WARN_ON(1); |
e8fa1362 | 1724 | return 0; |
f65eda4f | 1725 | } |
e8fa1362 SR |
1726 | |
1727 | /* | |
1728 | * It's possible that the next_task slipped in of | |
1729 | * higher priority than current. If that's the case | |
1730 | * just reschedule current. | |
1731 | */ | |
697f0a48 | 1732 | if (unlikely(next_task->prio < rq->curr->prio)) { |
8875125e | 1733 | resched_curr(rq); |
e8fa1362 SR |
1734 | return 0; |
1735 | } | |
1736 | ||
697f0a48 | 1737 | /* We might release rq lock */ |
e8fa1362 SR |
1738 | get_task_struct(next_task); |
1739 | ||
1740 | /* find_lock_lowest_rq locks the rq if found */ | |
697f0a48 | 1741 | lowest_rq = find_lock_lowest_rq(next_task, rq); |
e8fa1362 SR |
1742 | if (!lowest_rq) { |
1743 | struct task_struct *task; | |
1744 | /* | |
311e800e | 1745 | * find_lock_lowest_rq releases rq->lock |
1563513d GH |
1746 | * so it is possible that next_task has migrated. |
1747 | * | |
1748 | * We need to make sure that the task is still on the same | |
1749 | * run-queue and is also still the next task eligible for | |
1750 | * pushing. | |
e8fa1362 | 1751 | */ |
917b627d | 1752 | task = pick_next_pushable_task(rq); |
1563513d GH |
1753 | if (task_cpu(next_task) == rq->cpu && task == next_task) { |
1754 | /* | |
311e800e HD |
1755 | * The task hasn't migrated, and is still the next |
1756 | * eligible task, but we failed to find a run-queue | |
1757 | * to push it to. Do not retry in this case, since | |
1758 | * other cpus will pull from us when ready. | |
1563513d | 1759 | */ |
1563513d | 1760 | goto out; |
e8fa1362 | 1761 | } |
917b627d | 1762 | |
1563513d GH |
1763 | if (!task) |
1764 | /* No more tasks, just exit */ | |
1765 | goto out; | |
1766 | ||
917b627d | 1767 | /* |
1563513d | 1768 | * Something has shifted, try again. |
917b627d | 1769 | */ |
1563513d GH |
1770 | put_task_struct(next_task); |
1771 | next_task = task; | |
1772 | goto retry; | |
e8fa1362 SR |
1773 | } |
1774 | ||
697f0a48 | 1775 | deactivate_task(rq, next_task, 0); |
e8fa1362 SR |
1776 | set_task_cpu(next_task, lowest_rq->cpu); |
1777 | activate_task(lowest_rq, next_task, 0); | |
311e800e | 1778 | ret = 1; |
e8fa1362 | 1779 | |
8875125e | 1780 | resched_curr(lowest_rq); |
e8fa1362 | 1781 | |
1b12bbc7 | 1782 | double_unlock_balance(rq, lowest_rq); |
e8fa1362 | 1783 | |
e8fa1362 SR |
1784 | out: |
1785 | put_task_struct(next_task); | |
1786 | ||
311e800e | 1787 | return ret; |
e8fa1362 SR |
1788 | } |
1789 | ||
e8fa1362 SR |
1790 | static void push_rt_tasks(struct rq *rq) |
1791 | { | |
1792 | /* push_rt_task will return true if it moved an RT */ | |
1793 | while (push_rt_task(rq)) | |
1794 | ; | |
1795 | } | |
1796 | ||
b6366f04 SR |
1797 | #ifdef HAVE_RT_PUSH_IPI |
1798 | /* | |
1799 | * The search for the next cpu always starts at rq->cpu and ends | |
1800 | * when we reach rq->cpu again. It will never return rq->cpu. | |
1801 | * This returns the next cpu to check, or nr_cpu_ids if the loop | |
1802 | * is complete. | |
1803 | * | |
1804 | * rq->rt.push_cpu holds the last cpu returned by this function, | |
1805 | * or if this is the first instance, it must hold rq->cpu. | |
1806 | */ | |
1807 | static int rto_next_cpu(struct rq *rq) | |
1808 | { | |
1809 | int prev_cpu = rq->rt.push_cpu; | |
1810 | int cpu; | |
1811 | ||
1812 | cpu = cpumask_next(prev_cpu, rq->rd->rto_mask); | |
1813 | ||
1814 | /* | |
1815 | * If the previous cpu is less than the rq's CPU, then it already | |
1816 | * passed the end of the mask, and has started from the beginning. | |
1817 | * We end if the next CPU is greater or equal to rq's CPU. | |
1818 | */ | |
1819 | if (prev_cpu < rq->cpu) { | |
1820 | if (cpu >= rq->cpu) | |
1821 | return nr_cpu_ids; | |
1822 | ||
1823 | } else if (cpu >= nr_cpu_ids) { | |
1824 | /* | |
1825 | * We passed the end of the mask, start at the beginning. | |
1826 | * If the result is greater or equal to the rq's CPU, then | |
1827 | * the loop is finished. | |
1828 | */ | |
1829 | cpu = cpumask_first(rq->rd->rto_mask); | |
1830 | if (cpu >= rq->cpu) | |
1831 | return nr_cpu_ids; | |
1832 | } | |
1833 | rq->rt.push_cpu = cpu; | |
1834 | ||
1835 | /* Return cpu to let the caller know if the loop is finished or not */ | |
1836 | return cpu; | |
1837 | } | |
1838 | ||
1839 | static int find_next_push_cpu(struct rq *rq) | |
1840 | { | |
1841 | struct rq *next_rq; | |
1842 | int cpu; | |
1843 | ||
1844 | while (1) { | |
1845 | cpu = rto_next_cpu(rq); | |
1846 | if (cpu >= nr_cpu_ids) | |
1847 | break; | |
1848 | next_rq = cpu_rq(cpu); | |
1849 | ||
1850 | /* Make sure the next rq can push to this rq */ | |
1851 | if (next_rq->rt.highest_prio.next < rq->rt.highest_prio.curr) | |
1852 | break; | |
1853 | } | |
1854 | ||
1855 | return cpu; | |
1856 | } | |
1857 | ||
1858 | #define RT_PUSH_IPI_EXECUTING 1 | |
1859 | #define RT_PUSH_IPI_RESTART 2 | |
1860 | ||
1861 | static void tell_cpu_to_push(struct rq *rq) | |
1862 | { | |
1863 | int cpu; | |
1864 | ||
1865 | if (rq->rt.push_flags & RT_PUSH_IPI_EXECUTING) { | |
1866 | raw_spin_lock(&rq->rt.push_lock); | |
1867 | /* Make sure it's still executing */ | |
1868 | if (rq->rt.push_flags & RT_PUSH_IPI_EXECUTING) { | |
1869 | /* | |
1870 | * Tell the IPI to restart the loop as things have | |
1871 | * changed since it started. | |
1872 | */ | |
1873 | rq->rt.push_flags |= RT_PUSH_IPI_RESTART; | |
1874 | raw_spin_unlock(&rq->rt.push_lock); | |
1875 | return; | |
1876 | } | |
1877 | raw_spin_unlock(&rq->rt.push_lock); | |
1878 | } | |
1879 | ||
1880 | /* When here, there's no IPI going around */ | |
1881 | ||
1882 | rq->rt.push_cpu = rq->cpu; | |
1883 | cpu = find_next_push_cpu(rq); | |
1884 | if (cpu >= nr_cpu_ids) | |
1885 | return; | |
1886 | ||
1887 | rq->rt.push_flags = RT_PUSH_IPI_EXECUTING; | |
1888 | ||
1889 | irq_work_queue_on(&rq->rt.push_work, cpu); | |
1890 | } | |
1891 | ||
1892 | /* Called from hardirq context */ | |
1893 | static void try_to_push_tasks(void *arg) | |
1894 | { | |
1895 | struct rt_rq *rt_rq = arg; | |
1896 | struct rq *rq, *src_rq; | |
1897 | int this_cpu; | |
1898 | int cpu; | |
1899 | ||
1900 | this_cpu = rt_rq->push_cpu; | |
1901 | ||
1902 | /* Paranoid check */ | |
1903 | BUG_ON(this_cpu != smp_processor_id()); | |
1904 | ||
1905 | rq = cpu_rq(this_cpu); | |
1906 | src_rq = rq_of_rt_rq(rt_rq); | |
1907 | ||
1908 | again: | |
1909 | if (has_pushable_tasks(rq)) { | |
1910 | raw_spin_lock(&rq->lock); | |
1911 | push_rt_task(rq); | |
1912 | raw_spin_unlock(&rq->lock); | |
1913 | } | |
1914 | ||
1915 | /* Pass the IPI to the next rt overloaded queue */ | |
1916 | raw_spin_lock(&rt_rq->push_lock); | |
1917 | /* | |
1918 | * If the source queue changed since the IPI went out, | |
1919 | * we need to restart the search from that CPU again. | |
1920 | */ | |
1921 | if (rt_rq->push_flags & RT_PUSH_IPI_RESTART) { | |
1922 | rt_rq->push_flags &= ~RT_PUSH_IPI_RESTART; | |
1923 | rt_rq->push_cpu = src_rq->cpu; | |
1924 | } | |
1925 | ||
1926 | cpu = find_next_push_cpu(src_rq); | |
1927 | ||
1928 | if (cpu >= nr_cpu_ids) | |
1929 | rt_rq->push_flags &= ~RT_PUSH_IPI_EXECUTING; | |
1930 | raw_spin_unlock(&rt_rq->push_lock); | |
1931 | ||
1932 | if (cpu >= nr_cpu_ids) | |
1933 | return; | |
1934 | ||
1935 | /* | |
1936 | * It is possible that a restart caused this CPU to be | |
1937 | * chosen again. Don't bother with an IPI, just see if we | |
1938 | * have more to push. | |
1939 | */ | |
1940 | if (unlikely(cpu == rq->cpu)) | |
1941 | goto again; | |
1942 | ||
1943 | /* Try the next RT overloaded CPU */ | |
1944 | irq_work_queue_on(&rt_rq->push_work, cpu); | |
1945 | } | |
1946 | ||
1947 | static void push_irq_work_func(struct irq_work *work) | |
1948 | { | |
1949 | struct rt_rq *rt_rq = container_of(work, struct rt_rq, push_work); | |
1950 | ||
1951 | try_to_push_tasks(rt_rq); | |
1952 | } | |
1953 | #endif /* HAVE_RT_PUSH_IPI */ | |
1954 | ||
f65eda4f SR |
1955 | static int pull_rt_task(struct rq *this_rq) |
1956 | { | |
80bf3171 | 1957 | int this_cpu = this_rq->cpu, ret = 0, cpu; |
a8728944 | 1958 | struct task_struct *p; |
f65eda4f | 1959 | struct rq *src_rq; |
f65eda4f | 1960 | |
637f5085 | 1961 | if (likely(!rt_overloaded(this_rq))) |
f65eda4f SR |
1962 | return 0; |
1963 | ||
7c3f2ab7 PZ |
1964 | /* |
1965 | * Match the barrier from rt_set_overloaded; this guarantees that if we | |
1966 | * see overloaded we must also see the rto_mask bit. | |
1967 | */ | |
1968 | smp_rmb(); | |
1969 | ||
b6366f04 SR |
1970 | #ifdef HAVE_RT_PUSH_IPI |
1971 | if (sched_feat(RT_PUSH_IPI)) { | |
1972 | tell_cpu_to_push(this_rq); | |
1973 | return 0; | |
1974 | } | |
1975 | #endif | |
1976 | ||
c6c4927b | 1977 | for_each_cpu(cpu, this_rq->rd->rto_mask) { |
f65eda4f SR |
1978 | if (this_cpu == cpu) |
1979 | continue; | |
1980 | ||
1981 | src_rq = cpu_rq(cpu); | |
74ab8e4f GH |
1982 | |
1983 | /* | |
1984 | * Don't bother taking the src_rq->lock if the next highest | |
1985 | * task is known to be lower-priority than our current task. | |
1986 | * This may look racy, but if this value is about to go | |
1987 | * logically higher, the src_rq will push this task away. | |
1988 | * And if its going logically lower, we do not care | |
1989 | */ | |
1990 | if (src_rq->rt.highest_prio.next >= | |
1991 | this_rq->rt.highest_prio.curr) | |
1992 | continue; | |
1993 | ||
f65eda4f SR |
1994 | /* |
1995 | * We can potentially drop this_rq's lock in | |
1996 | * double_lock_balance, and another CPU could | |
a8728944 | 1997 | * alter this_rq |
f65eda4f | 1998 | */ |
a8728944 | 1999 | double_lock_balance(this_rq, src_rq); |
f65eda4f SR |
2000 | |
2001 | /* | |
e23ee747 KT |
2002 | * We can pull only a task, which is pushable |
2003 | * on its rq, and no others. | |
f65eda4f | 2004 | */ |
e23ee747 | 2005 | p = pick_highest_pushable_task(src_rq, this_cpu); |
f65eda4f SR |
2006 | |
2007 | /* | |
2008 | * Do we have an RT task that preempts | |
2009 | * the to-be-scheduled task? | |
2010 | */ | |
a8728944 | 2011 | if (p && (p->prio < this_rq->rt.highest_prio.curr)) { |
f65eda4f | 2012 | WARN_ON(p == src_rq->curr); |
da0c1e65 | 2013 | WARN_ON(!task_on_rq_queued(p)); |
f65eda4f SR |
2014 | |
2015 | /* | |
2016 | * There's a chance that p is higher in priority | |
2017 | * than what's currently running on its cpu. | |
2018 | * This is just that p is wakeing up and hasn't | |
2019 | * had a chance to schedule. We only pull | |
2020 | * p if it is lower in priority than the | |
a8728944 | 2021 | * current task on the run queue |
f65eda4f | 2022 | */ |
a8728944 | 2023 | if (p->prio < src_rq->curr->prio) |
614ee1f6 | 2024 | goto skip; |
f65eda4f SR |
2025 | |
2026 | ret = 1; | |
2027 | ||
2028 | deactivate_task(src_rq, p, 0); | |
2029 | set_task_cpu(p, this_cpu); | |
2030 | activate_task(this_rq, p, 0); | |
2031 | /* | |
2032 | * We continue with the search, just in | |
2033 | * case there's an even higher prio task | |
25985edc | 2034 | * in another runqueue. (low likelihood |
f65eda4f | 2035 | * but possible) |
f65eda4f | 2036 | */ |
f65eda4f | 2037 | } |
49246274 | 2038 | skip: |
1b12bbc7 | 2039 | double_unlock_balance(this_rq, src_rq); |
f65eda4f SR |
2040 | } |
2041 | ||
2042 | return ret; | |
2043 | } | |
2044 | ||
9a897c5a | 2045 | static void post_schedule_rt(struct rq *rq) |
e8fa1362 | 2046 | { |
967fc046 | 2047 | push_rt_tasks(rq); |
e8fa1362 SR |
2048 | } |
2049 | ||
8ae121ac GH |
2050 | /* |
2051 | * If we are not running and we are not going to reschedule soon, we should | |
2052 | * try to push tasks away now | |
2053 | */ | |
efbbd05a | 2054 | static void task_woken_rt(struct rq *rq, struct task_struct *p) |
4642dafd | 2055 | { |
9a897c5a | 2056 | if (!task_running(rq, p) && |
8ae121ac | 2057 | !test_tsk_need_resched(rq->curr) && |
917b627d | 2058 | has_pushable_tasks(rq) && |
29baa747 | 2059 | p->nr_cpus_allowed > 1 && |
1baca4ce | 2060 | (dl_task(rq->curr) || rt_task(rq->curr)) && |
29baa747 | 2061 | (rq->curr->nr_cpus_allowed < 2 || |
3be209a8 | 2062 | rq->curr->prio <= p->prio)) |
4642dafd SR |
2063 | push_rt_tasks(rq); |
2064 | } | |
2065 | ||
cd8ba7cd | 2066 | static void set_cpus_allowed_rt(struct task_struct *p, |
96f874e2 | 2067 | const struct cpumask *new_mask) |
73fe6aae | 2068 | { |
8d3d5ada KT |
2069 | struct rq *rq; |
2070 | int weight; | |
73fe6aae GH |
2071 | |
2072 | BUG_ON(!rt_task(p)); | |
2073 | ||
da0c1e65 | 2074 | if (!task_on_rq_queued(p)) |
8d3d5ada | 2075 | return; |
917b627d | 2076 | |
8d3d5ada | 2077 | weight = cpumask_weight(new_mask); |
917b627d | 2078 | |
8d3d5ada KT |
2079 | /* |
2080 | * Only update if the process changes its state from whether it | |
2081 | * can migrate or not. | |
2082 | */ | |
29baa747 | 2083 | if ((p->nr_cpus_allowed > 1) == (weight > 1)) |
8d3d5ada | 2084 | return; |
917b627d | 2085 | |
8d3d5ada | 2086 | rq = task_rq(p); |
73fe6aae | 2087 | |
8d3d5ada KT |
2088 | /* |
2089 | * The process used to be able to migrate OR it can now migrate | |
2090 | */ | |
2091 | if (weight <= 1) { | |
2092 | if (!task_current(rq, p)) | |
2093 | dequeue_pushable_task(rq, p); | |
2094 | BUG_ON(!rq->rt.rt_nr_migratory); | |
2095 | rq->rt.rt_nr_migratory--; | |
2096 | } else { | |
2097 | if (!task_current(rq, p)) | |
2098 | enqueue_pushable_task(rq, p); | |
2099 | rq->rt.rt_nr_migratory++; | |
73fe6aae | 2100 | } |
8d3d5ada KT |
2101 | |
2102 | update_rt_migration(&rq->rt); | |
73fe6aae | 2103 | } |
deeeccd4 | 2104 | |
bdd7c81b | 2105 | /* Assumes rq->lock is held */ |
1f11eb6a | 2106 | static void rq_online_rt(struct rq *rq) |
bdd7c81b IM |
2107 | { |
2108 | if (rq->rt.overloaded) | |
2109 | rt_set_overload(rq); | |
6e0534f2 | 2110 | |
7def2be1 PZ |
2111 | __enable_runtime(rq); |
2112 | ||
e864c499 | 2113 | cpupri_set(&rq->rd->cpupri, rq->cpu, rq->rt.highest_prio.curr); |
bdd7c81b IM |
2114 | } |
2115 | ||
2116 | /* Assumes rq->lock is held */ | |
1f11eb6a | 2117 | static void rq_offline_rt(struct rq *rq) |
bdd7c81b IM |
2118 | { |
2119 | if (rq->rt.overloaded) | |
2120 | rt_clear_overload(rq); | |
6e0534f2 | 2121 | |
7def2be1 PZ |
2122 | __disable_runtime(rq); |
2123 | ||
6e0534f2 | 2124 | cpupri_set(&rq->rd->cpupri, rq->cpu, CPUPRI_INVALID); |
bdd7c81b | 2125 | } |
cb469845 SR |
2126 | |
2127 | /* | |
2128 | * When switch from the rt queue, we bring ourselves to a position | |
2129 | * that we might want to pull RT tasks from other runqueues. | |
2130 | */ | |
da7a735e | 2131 | static void switched_from_rt(struct rq *rq, struct task_struct *p) |
cb469845 SR |
2132 | { |
2133 | /* | |
2134 | * If there are other RT tasks then we will reschedule | |
2135 | * and the scheduling of the other RT tasks will handle | |
2136 | * the balancing. But if we are the last RT task | |
2137 | * we may need to handle the pulling of RT tasks | |
2138 | * now. | |
2139 | */ | |
da0c1e65 | 2140 | if (!task_on_rq_queued(p) || rq->rt.rt_nr_running) |
1158ddb5 KT |
2141 | return; |
2142 | ||
2143 | if (pull_rt_task(rq)) | |
8875125e | 2144 | resched_curr(rq); |
cb469845 | 2145 | } |
3d8cbdf8 | 2146 | |
11c785b7 | 2147 | void __init init_sched_rt_class(void) |
3d8cbdf8 RR |
2148 | { |
2149 | unsigned int i; | |
2150 | ||
029632fb | 2151 | for_each_possible_cpu(i) { |
eaa95840 | 2152 | zalloc_cpumask_var_node(&per_cpu(local_cpu_mask, i), |
6ca09dfc | 2153 | GFP_KERNEL, cpu_to_node(i)); |
029632fb | 2154 | } |
3d8cbdf8 | 2155 | } |
cb469845 SR |
2156 | #endif /* CONFIG_SMP */ |
2157 | ||
2158 | /* | |
2159 | * When switching a task to RT, we may overload the runqueue | |
2160 | * with RT tasks. In this case we try to push them off to | |
2161 | * other runqueues. | |
2162 | */ | |
da7a735e | 2163 | static void switched_to_rt(struct rq *rq, struct task_struct *p) |
cb469845 SR |
2164 | { |
2165 | int check_resched = 1; | |
2166 | ||
2167 | /* | |
2168 | * If we are already running, then there's nothing | |
2169 | * that needs to be done. But if we are not running | |
2170 | * we may need to preempt the current running task. | |
2171 | * If that current running task is also an RT task | |
2172 | * then see if we can move to another run queue. | |
2173 | */ | |
da0c1e65 | 2174 | if (task_on_rq_queued(p) && rq->curr != p) { |
cb469845 | 2175 | #ifdef CONFIG_SMP |
10447917 | 2176 | if (p->nr_cpus_allowed > 1 && rq->rt.overloaded && |
cb469845 | 2177 | /* Don't resched if we changed runqueues */ |
10447917 | 2178 | push_rt_task(rq) && rq != task_rq(p)) |
cb469845 SR |
2179 | check_resched = 0; |
2180 | #endif /* CONFIG_SMP */ | |
2181 | if (check_resched && p->prio < rq->curr->prio) | |
8875125e | 2182 | resched_curr(rq); |
cb469845 SR |
2183 | } |
2184 | } | |
2185 | ||
2186 | /* | |
2187 | * Priority of the task has changed. This may cause | |
2188 | * us to initiate a push or pull. | |
2189 | */ | |
da7a735e PZ |
2190 | static void |
2191 | prio_changed_rt(struct rq *rq, struct task_struct *p, int oldprio) | |
cb469845 | 2192 | { |
da0c1e65 | 2193 | if (!task_on_rq_queued(p)) |
da7a735e PZ |
2194 | return; |
2195 | ||
2196 | if (rq->curr == p) { | |
cb469845 SR |
2197 | #ifdef CONFIG_SMP |
2198 | /* | |
2199 | * If our priority decreases while running, we | |
2200 | * may need to pull tasks to this runqueue. | |
2201 | */ | |
2202 | if (oldprio < p->prio) | |
2203 | pull_rt_task(rq); | |
2204 | /* | |
2205 | * If there's a higher priority task waiting to run | |
6fa46fa5 SR |
2206 | * then reschedule. Note, the above pull_rt_task |
2207 | * can release the rq lock and p could migrate. | |
2208 | * Only reschedule if p is still on the same runqueue. | |
cb469845 | 2209 | */ |
e864c499 | 2210 | if (p->prio > rq->rt.highest_prio.curr && rq->curr == p) |
8875125e | 2211 | resched_curr(rq); |
cb469845 SR |
2212 | #else |
2213 | /* For UP simply resched on drop of prio */ | |
2214 | if (oldprio < p->prio) | |
8875125e | 2215 | resched_curr(rq); |
e8fa1362 | 2216 | #endif /* CONFIG_SMP */ |
cb469845 SR |
2217 | } else { |
2218 | /* | |
2219 | * This task is not running, but if it is | |
2220 | * greater than the current running task | |
2221 | * then reschedule. | |
2222 | */ | |
2223 | if (p->prio < rq->curr->prio) | |
8875125e | 2224 | resched_curr(rq); |
cb469845 SR |
2225 | } |
2226 | } | |
2227 | ||
78f2c7db PZ |
2228 | static void watchdog(struct rq *rq, struct task_struct *p) |
2229 | { | |
2230 | unsigned long soft, hard; | |
2231 | ||
78d7d407 JS |
2232 | /* max may change after cur was read, this will be fixed next tick */ |
2233 | soft = task_rlimit(p, RLIMIT_RTTIME); | |
2234 | hard = task_rlimit_max(p, RLIMIT_RTTIME); | |
78f2c7db PZ |
2235 | |
2236 | if (soft != RLIM_INFINITY) { | |
2237 | unsigned long next; | |
2238 | ||
57d2aa00 YX |
2239 | if (p->rt.watchdog_stamp != jiffies) { |
2240 | p->rt.timeout++; | |
2241 | p->rt.watchdog_stamp = jiffies; | |
2242 | } | |
2243 | ||
78f2c7db | 2244 | next = DIV_ROUND_UP(min(soft, hard), USEC_PER_SEC/HZ); |
5a52dd50 | 2245 | if (p->rt.timeout > next) |
f06febc9 | 2246 | p->cputime_expires.sched_exp = p->se.sum_exec_runtime; |
78f2c7db PZ |
2247 | } |
2248 | } | |
bb44e5d1 | 2249 | |
8f4d37ec | 2250 | static void task_tick_rt(struct rq *rq, struct task_struct *p, int queued) |
bb44e5d1 | 2251 | { |
454c7999 CC |
2252 | struct sched_rt_entity *rt_se = &p->rt; |
2253 | ||
67e2be02 PZ |
2254 | update_curr_rt(rq); |
2255 | ||
78f2c7db PZ |
2256 | watchdog(rq, p); |
2257 | ||
bb44e5d1 IM |
2258 | /* |
2259 | * RR tasks need a special form of timeslice management. | |
2260 | * FIFO tasks have no timeslices. | |
2261 | */ | |
2262 | if (p->policy != SCHED_RR) | |
2263 | return; | |
2264 | ||
fa717060 | 2265 | if (--p->rt.time_slice) |
bb44e5d1 IM |
2266 | return; |
2267 | ||
ce0dbbbb | 2268 | p->rt.time_slice = sched_rr_timeslice; |
bb44e5d1 | 2269 | |
98fbc798 | 2270 | /* |
e9aa39bb LB |
2271 | * Requeue to the end of queue if we (and all of our ancestors) are not |
2272 | * the only element on the queue | |
98fbc798 | 2273 | */ |
454c7999 CC |
2274 | for_each_sched_rt_entity(rt_se) { |
2275 | if (rt_se->run_list.prev != rt_se->run_list.next) { | |
2276 | requeue_task_rt(rq, p, 0); | |
8aa6f0eb | 2277 | resched_curr(rq); |
454c7999 CC |
2278 | return; |
2279 | } | |
98fbc798 | 2280 | } |
bb44e5d1 IM |
2281 | } |
2282 | ||
83b699ed SV |
2283 | static void set_curr_task_rt(struct rq *rq) |
2284 | { | |
2285 | struct task_struct *p = rq->curr; | |
2286 | ||
78becc27 | 2287 | p->se.exec_start = rq_clock_task(rq); |
917b627d GH |
2288 | |
2289 | /* The running task is never eligible for pushing */ | |
2290 | dequeue_pushable_task(rq, p); | |
83b699ed SV |
2291 | } |
2292 | ||
6d686f45 | 2293 | static unsigned int get_rr_interval_rt(struct rq *rq, struct task_struct *task) |
0d721cea PW |
2294 | { |
2295 | /* | |
2296 | * Time slice is 0 for SCHED_FIFO tasks | |
2297 | */ | |
2298 | if (task->policy == SCHED_RR) | |
ce0dbbbb | 2299 | return sched_rr_timeslice; |
0d721cea PW |
2300 | else |
2301 | return 0; | |
2302 | } | |
2303 | ||
029632fb | 2304 | const struct sched_class rt_sched_class = { |
5522d5d5 | 2305 | .next = &fair_sched_class, |
bb44e5d1 IM |
2306 | .enqueue_task = enqueue_task_rt, |
2307 | .dequeue_task = dequeue_task_rt, | |
2308 | .yield_task = yield_task_rt, | |
2309 | ||
2310 | .check_preempt_curr = check_preempt_curr_rt, | |
2311 | ||
2312 | .pick_next_task = pick_next_task_rt, | |
2313 | .put_prev_task = put_prev_task_rt, | |
2314 | ||
681f3e68 | 2315 | #ifdef CONFIG_SMP |
4ce72a2c LZ |
2316 | .select_task_rq = select_task_rq_rt, |
2317 | ||
73fe6aae | 2318 | .set_cpus_allowed = set_cpus_allowed_rt, |
1f11eb6a GH |
2319 | .rq_online = rq_online_rt, |
2320 | .rq_offline = rq_offline_rt, | |
9a897c5a | 2321 | .post_schedule = post_schedule_rt, |
efbbd05a | 2322 | .task_woken = task_woken_rt, |
cb469845 | 2323 | .switched_from = switched_from_rt, |
681f3e68 | 2324 | #endif |
bb44e5d1 | 2325 | |
83b699ed | 2326 | .set_curr_task = set_curr_task_rt, |
bb44e5d1 | 2327 | .task_tick = task_tick_rt, |
cb469845 | 2328 | |
0d721cea PW |
2329 | .get_rr_interval = get_rr_interval_rt, |
2330 | ||
cb469845 SR |
2331 | .prio_changed = prio_changed_rt, |
2332 | .switched_to = switched_to_rt, | |
6e998916 SG |
2333 | |
2334 | .update_curr = update_curr_rt, | |
bb44e5d1 | 2335 | }; |
ada18de2 PZ |
2336 | |
2337 | #ifdef CONFIG_SCHED_DEBUG | |
2338 | extern void print_rt_rq(struct seq_file *m, int cpu, struct rt_rq *rt_rq); | |
2339 | ||
029632fb | 2340 | void print_rt_stats(struct seq_file *m, int cpu) |
ada18de2 | 2341 | { |
ec514c48 | 2342 | rt_rq_iter_t iter; |
ada18de2 PZ |
2343 | struct rt_rq *rt_rq; |
2344 | ||
2345 | rcu_read_lock(); | |
ec514c48 | 2346 | for_each_rt_rq(rt_rq, iter, cpu_rq(cpu)) |
ada18de2 PZ |
2347 | print_rt_rq(m, cpu, rt_rq); |
2348 | rcu_read_unlock(); | |
2349 | } | |
55e12e5e | 2350 | #endif /* CONFIG_SCHED_DEBUG */ |