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