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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
aab03e05 DF |
2 | /* |
3 | * Deadline Scheduling Class (SCHED_DEADLINE) | |
4 | * | |
5 | * Earliest Deadline First (EDF) + Constant Bandwidth Server (CBS). | |
6 | * | |
7 | * Tasks that periodically executes their instances for less than their | |
8 | * runtime won't miss any of their deadlines. | |
9 | * Tasks that are not periodic or sporadic or that tries to execute more | |
10 | * than their reserved bandwidth will be slowed down (and may potentially | |
11 | * miss some of their deadlines), and won't affect any other task. | |
12 | * | |
13 | * Copyright (C) 2012 Dario Faggioli <raistlin@linux.it>, | |
1baca4ce | 14 | * Juri Lelli <juri.lelli@gmail.com>, |
aab03e05 DF |
15 | * Michael Trimarchi <michael@amarulasolutions.com>, |
16 | * Fabio Checconi <fchecconi@gmail.com> | |
17 | */ | |
18 | #include "sched.h" | |
3727e0e1 | 19 | #include "pelt.h" |
aab03e05 | 20 | |
332ac17e DF |
21 | struct dl_bandwidth def_dl_bandwidth; |
22 | ||
aab03e05 DF |
23 | static inline struct task_struct *dl_task_of(struct sched_dl_entity *dl_se) |
24 | { | |
25 | return container_of(dl_se, struct task_struct, dl); | |
26 | } | |
27 | ||
28 | static inline struct rq *rq_of_dl_rq(struct dl_rq *dl_rq) | |
29 | { | |
30 | return container_of(dl_rq, struct rq, dl); | |
31 | } | |
32 | ||
33 | static inline struct dl_rq *dl_rq_of_se(struct sched_dl_entity *dl_se) | |
34 | { | |
35 | struct task_struct *p = dl_task_of(dl_se); | |
36 | struct rq *rq = task_rq(p); | |
37 | ||
38 | return &rq->dl; | |
39 | } | |
40 | ||
41 | static inline int on_dl_rq(struct sched_dl_entity *dl_se) | |
42 | { | |
43 | return !RB_EMPTY_NODE(&dl_se->rb_node); | |
44 | } | |
45 | ||
2279f540 JL |
46 | #ifdef CONFIG_RT_MUTEXES |
47 | static inline struct sched_dl_entity *pi_of(struct sched_dl_entity *dl_se) | |
48 | { | |
49 | return dl_se->pi_se; | |
50 | } | |
51 | ||
52 | static inline bool is_dl_boosted(struct sched_dl_entity *dl_se) | |
53 | { | |
54 | return pi_of(dl_se) != dl_se; | |
55 | } | |
56 | #else | |
57 | static inline struct sched_dl_entity *pi_of(struct sched_dl_entity *dl_se) | |
58 | { | |
59 | return dl_se; | |
60 | } | |
61 | ||
62 | static inline bool is_dl_boosted(struct sched_dl_entity *dl_se) | |
63 | { | |
64 | return false; | |
65 | } | |
66 | #endif | |
67 | ||
06a76fe0 NP |
68 | #ifdef CONFIG_SMP |
69 | static inline struct dl_bw *dl_bw_of(int i) | |
70 | { | |
71 | RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held(), | |
72 | "sched RCU must be held"); | |
73 | return &cpu_rq(i)->rd->dl_bw; | |
74 | } | |
75 | ||
76 | static inline int dl_bw_cpus(int i) | |
77 | { | |
78 | struct root_domain *rd = cpu_rq(i)->rd; | |
c81b8932 | 79 | int cpus; |
06a76fe0 NP |
80 | |
81 | RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held(), | |
82 | "sched RCU must be held"); | |
c81b8932 DE |
83 | |
84 | if (cpumask_subset(rd->span, cpu_active_mask)) | |
85 | return cpumask_weight(rd->span); | |
86 | ||
87 | cpus = 0; | |
88 | ||
06a76fe0 NP |
89 | for_each_cpu_and(i, rd->span, cpu_active_mask) |
90 | cpus++; | |
91 | ||
92 | return cpus; | |
93 | } | |
fc9dc698 DE |
94 | |
95 | static inline unsigned long __dl_bw_capacity(int i) | |
96 | { | |
97 | struct root_domain *rd = cpu_rq(i)->rd; | |
98 | unsigned long cap = 0; | |
99 | ||
100 | RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held(), | |
101 | "sched RCU must be held"); | |
102 | ||
103 | for_each_cpu_and(i, rd->span, cpu_active_mask) | |
104 | cap += capacity_orig_of(i); | |
105 | ||
106 | return cap; | |
107 | } | |
108 | ||
109 | /* | |
110 | * XXX Fix: If 'rq->rd == def_root_domain' perform AC against capacity | |
111 | * of the CPU the task is running on rather rd's \Sum CPU capacity. | |
112 | */ | |
113 | static inline unsigned long dl_bw_capacity(int i) | |
114 | { | |
115 | if (!static_branch_unlikely(&sched_asym_cpucapacity) && | |
116 | capacity_orig_of(i) == SCHED_CAPACITY_SCALE) { | |
117 | return dl_bw_cpus(i) << SCHED_CAPACITY_SHIFT; | |
118 | } else { | |
119 | return __dl_bw_capacity(i); | |
120 | } | |
121 | } | |
26762423 PL |
122 | |
123 | static inline bool dl_bw_visited(int cpu, u64 gen) | |
124 | { | |
125 | struct root_domain *rd = cpu_rq(cpu)->rd; | |
126 | ||
127 | if (rd->visit_gen == gen) | |
128 | return true; | |
129 | ||
130 | rd->visit_gen = gen; | |
131 | return false; | |
132 | } | |
06a76fe0 NP |
133 | #else |
134 | static inline struct dl_bw *dl_bw_of(int i) | |
135 | { | |
136 | return &cpu_rq(i)->dl.dl_bw; | |
137 | } | |
138 | ||
139 | static inline int dl_bw_cpus(int i) | |
140 | { | |
141 | return 1; | |
142 | } | |
fc9dc698 DE |
143 | |
144 | static inline unsigned long dl_bw_capacity(int i) | |
145 | { | |
146 | return SCHED_CAPACITY_SCALE; | |
147 | } | |
26762423 PL |
148 | |
149 | static inline bool dl_bw_visited(int cpu, u64 gen) | |
150 | { | |
151 | return false; | |
152 | } | |
06a76fe0 NP |
153 | #endif |
154 | ||
e36d8677 | 155 | static inline |
794a56eb | 156 | void __add_running_bw(u64 dl_bw, struct dl_rq *dl_rq) |
e36d8677 LA |
157 | { |
158 | u64 old = dl_rq->running_bw; | |
159 | ||
5cb9eaa3 | 160 | lockdep_assert_rq_held(rq_of_dl_rq(dl_rq)); |
e36d8677 LA |
161 | dl_rq->running_bw += dl_bw; |
162 | SCHED_WARN_ON(dl_rq->running_bw < old); /* overflow */ | |
8fd27231 | 163 | SCHED_WARN_ON(dl_rq->running_bw > dl_rq->this_bw); |
e0367b12 | 164 | /* kick cpufreq (see the comment in kernel/sched/sched.h). */ |
4042d003 | 165 | cpufreq_update_util(rq_of_dl_rq(dl_rq), 0); |
e36d8677 LA |
166 | } |
167 | ||
168 | static inline | |
794a56eb | 169 | void __sub_running_bw(u64 dl_bw, struct dl_rq *dl_rq) |
e36d8677 LA |
170 | { |
171 | u64 old = dl_rq->running_bw; | |
172 | ||
5cb9eaa3 | 173 | lockdep_assert_rq_held(rq_of_dl_rq(dl_rq)); |
e36d8677 LA |
174 | dl_rq->running_bw -= dl_bw; |
175 | SCHED_WARN_ON(dl_rq->running_bw > old); /* underflow */ | |
176 | if (dl_rq->running_bw > old) | |
177 | dl_rq->running_bw = 0; | |
e0367b12 | 178 | /* kick cpufreq (see the comment in kernel/sched/sched.h). */ |
4042d003 | 179 | cpufreq_update_util(rq_of_dl_rq(dl_rq), 0); |
e36d8677 LA |
180 | } |
181 | ||
8fd27231 | 182 | static inline |
794a56eb | 183 | void __add_rq_bw(u64 dl_bw, struct dl_rq *dl_rq) |
8fd27231 LA |
184 | { |
185 | u64 old = dl_rq->this_bw; | |
186 | ||
5cb9eaa3 | 187 | lockdep_assert_rq_held(rq_of_dl_rq(dl_rq)); |
8fd27231 LA |
188 | dl_rq->this_bw += dl_bw; |
189 | SCHED_WARN_ON(dl_rq->this_bw < old); /* overflow */ | |
190 | } | |
191 | ||
192 | static inline | |
794a56eb | 193 | void __sub_rq_bw(u64 dl_bw, struct dl_rq *dl_rq) |
8fd27231 LA |
194 | { |
195 | u64 old = dl_rq->this_bw; | |
196 | ||
5cb9eaa3 | 197 | lockdep_assert_rq_held(rq_of_dl_rq(dl_rq)); |
8fd27231 LA |
198 | dl_rq->this_bw -= dl_bw; |
199 | SCHED_WARN_ON(dl_rq->this_bw > old); /* underflow */ | |
200 | if (dl_rq->this_bw > old) | |
201 | dl_rq->this_bw = 0; | |
202 | SCHED_WARN_ON(dl_rq->running_bw > dl_rq->this_bw); | |
203 | } | |
204 | ||
794a56eb JL |
205 | static inline |
206 | void add_rq_bw(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq) | |
207 | { | |
208 | if (!dl_entity_is_special(dl_se)) | |
209 | __add_rq_bw(dl_se->dl_bw, dl_rq); | |
210 | } | |
211 | ||
212 | static inline | |
213 | void sub_rq_bw(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq) | |
214 | { | |
215 | if (!dl_entity_is_special(dl_se)) | |
216 | __sub_rq_bw(dl_se->dl_bw, dl_rq); | |
217 | } | |
218 | ||
219 | static inline | |
220 | void add_running_bw(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq) | |
221 | { | |
222 | if (!dl_entity_is_special(dl_se)) | |
223 | __add_running_bw(dl_se->dl_bw, dl_rq); | |
224 | } | |
225 | ||
226 | static inline | |
227 | void sub_running_bw(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq) | |
228 | { | |
229 | if (!dl_entity_is_special(dl_se)) | |
230 | __sub_running_bw(dl_se->dl_bw, dl_rq); | |
231 | } | |
232 | ||
ba4f7bc1 | 233 | static void dl_change_utilization(struct task_struct *p, u64 new_bw) |
209a0cbd | 234 | { |
8fd27231 | 235 | struct rq *rq; |
209a0cbd | 236 | |
794a56eb JL |
237 | BUG_ON(p->dl.flags & SCHED_FLAG_SUGOV); |
238 | ||
8fd27231 | 239 | if (task_on_rq_queued(p)) |
209a0cbd LA |
240 | return; |
241 | ||
8fd27231 LA |
242 | rq = task_rq(p); |
243 | if (p->dl.dl_non_contending) { | |
794a56eb | 244 | sub_running_bw(&p->dl, &rq->dl); |
8fd27231 LA |
245 | p->dl.dl_non_contending = 0; |
246 | /* | |
247 | * If the timer handler is currently running and the | |
3b03706f | 248 | * timer cannot be canceled, inactive_task_timer() |
8fd27231 LA |
249 | * will see that dl_not_contending is not set, and |
250 | * will not touch the rq's active utilization, | |
251 | * so we are still safe. | |
252 | */ | |
253 | if (hrtimer_try_to_cancel(&p->dl.inactive_timer) == 1) | |
254 | put_task_struct(p); | |
255 | } | |
794a56eb JL |
256 | __sub_rq_bw(p->dl.dl_bw, &rq->dl); |
257 | __add_rq_bw(new_bw, &rq->dl); | |
209a0cbd LA |
258 | } |
259 | ||
260 | /* | |
261 | * The utilization of a task cannot be immediately removed from | |
262 | * the rq active utilization (running_bw) when the task blocks. | |
263 | * Instead, we have to wait for the so called "0-lag time". | |
264 | * | |
265 | * If a task blocks before the "0-lag time", a timer (the inactive | |
266 | * timer) is armed, and running_bw is decreased when the timer | |
267 | * fires. | |
268 | * | |
269 | * If the task wakes up again before the inactive timer fires, | |
3b03706f | 270 | * the timer is canceled, whereas if the task wakes up after the |
209a0cbd LA |
271 | * inactive timer fired (and running_bw has been decreased) the |
272 | * task's utilization has to be added to running_bw again. | |
273 | * A flag in the deadline scheduling entity (dl_non_contending) | |
274 | * is used to avoid race conditions between the inactive timer handler | |
275 | * and task wakeups. | |
276 | * | |
277 | * The following diagram shows how running_bw is updated. A task is | |
278 | * "ACTIVE" when its utilization contributes to running_bw; an | |
279 | * "ACTIVE contending" task is in the TASK_RUNNING state, while an | |
280 | * "ACTIVE non contending" task is a blocked task for which the "0-lag time" | |
281 | * has not passed yet. An "INACTIVE" task is a task for which the "0-lag" | |
282 | * time already passed, which does not contribute to running_bw anymore. | |
283 | * +------------------+ | |
284 | * wakeup | ACTIVE | | |
285 | * +------------------>+ contending | | |
286 | * | add_running_bw | | | |
287 | * | +----+------+------+ | |
288 | * | | ^ | |
289 | * | dequeue | | | |
290 | * +--------+-------+ | | | |
291 | * | | t >= 0-lag | | wakeup | |
292 | * | INACTIVE |<---------------+ | | |
293 | * | | sub_running_bw | | | |
294 | * +--------+-------+ | | | |
295 | * ^ | | | |
296 | * | t < 0-lag | | | |
297 | * | | | | |
298 | * | V | | |
299 | * | +----+------+------+ | |
300 | * | sub_running_bw | ACTIVE | | |
301 | * +-------------------+ | | |
302 | * inactive timer | non contending | | |
303 | * fired +------------------+ | |
304 | * | |
305 | * The task_non_contending() function is invoked when a task | |
306 | * blocks, and checks if the 0-lag time already passed or | |
307 | * not (in the first case, it directly updates running_bw; | |
308 | * in the second case, it arms the inactive timer). | |
309 | * | |
310 | * The task_contending() function is invoked when a task wakes | |
311 | * up, and checks if the task is still in the "ACTIVE non contending" | |
312 | * state or not (in the second case, it updates running_bw). | |
313 | */ | |
314 | static void task_non_contending(struct task_struct *p) | |
315 | { | |
316 | struct sched_dl_entity *dl_se = &p->dl; | |
317 | struct hrtimer *timer = &dl_se->inactive_timer; | |
318 | struct dl_rq *dl_rq = dl_rq_of_se(dl_se); | |
319 | struct rq *rq = rq_of_dl_rq(dl_rq); | |
320 | s64 zerolag_time; | |
321 | ||
322 | /* | |
323 | * If this is a non-deadline task that has been boosted, | |
324 | * do nothing | |
325 | */ | |
326 | if (dl_se->dl_runtime == 0) | |
327 | return; | |
328 | ||
794a56eb JL |
329 | if (dl_entity_is_special(dl_se)) |
330 | return; | |
331 | ||
209a0cbd LA |
332 | WARN_ON(dl_se->dl_non_contending); |
333 | ||
334 | zerolag_time = dl_se->deadline - | |
335 | div64_long((dl_se->runtime * dl_se->dl_period), | |
336 | dl_se->dl_runtime); | |
337 | ||
338 | /* | |
339 | * Using relative times instead of the absolute "0-lag time" | |
340 | * allows to simplify the code | |
341 | */ | |
342 | zerolag_time -= rq_clock(rq); | |
343 | ||
344 | /* | |
345 | * If the "0-lag time" already passed, decrease the active | |
346 | * utilization now, instead of starting a timer | |
347 | */ | |
1b02cd6a | 348 | if ((zerolag_time < 0) || hrtimer_active(&dl_se->inactive_timer)) { |
209a0cbd | 349 | if (dl_task(p)) |
794a56eb | 350 | sub_running_bw(dl_se, dl_rq); |
2f064a59 | 351 | if (!dl_task(p) || READ_ONCE(p->__state) == TASK_DEAD) { |
387e3130 LA |
352 | struct dl_bw *dl_b = dl_bw_of(task_cpu(p)); |
353 | ||
2f064a59 | 354 | if (READ_ONCE(p->__state) == TASK_DEAD) |
794a56eb | 355 | sub_rq_bw(&p->dl, &rq->dl); |
387e3130 | 356 | raw_spin_lock(&dl_b->lock); |
8c0944ce | 357 | __dl_sub(dl_b, p->dl.dl_bw, dl_bw_cpus(task_cpu(p))); |
209a0cbd | 358 | __dl_clear_params(p); |
387e3130 LA |
359 | raw_spin_unlock(&dl_b->lock); |
360 | } | |
209a0cbd LA |
361 | |
362 | return; | |
363 | } | |
364 | ||
365 | dl_se->dl_non_contending = 1; | |
366 | get_task_struct(p); | |
850377a8 | 367 | hrtimer_start(timer, ns_to_ktime(zerolag_time), HRTIMER_MODE_REL_HARD); |
209a0cbd LA |
368 | } |
369 | ||
8fd27231 | 370 | static void task_contending(struct sched_dl_entity *dl_se, int flags) |
209a0cbd LA |
371 | { |
372 | struct dl_rq *dl_rq = dl_rq_of_se(dl_se); | |
373 | ||
374 | /* | |
375 | * If this is a non-deadline task that has been boosted, | |
376 | * do nothing | |
377 | */ | |
378 | if (dl_se->dl_runtime == 0) | |
379 | return; | |
380 | ||
8fd27231 | 381 | if (flags & ENQUEUE_MIGRATED) |
794a56eb | 382 | add_rq_bw(dl_se, dl_rq); |
8fd27231 | 383 | |
209a0cbd LA |
384 | if (dl_se->dl_non_contending) { |
385 | dl_se->dl_non_contending = 0; | |
386 | /* | |
387 | * If the timer handler is currently running and the | |
3b03706f | 388 | * timer cannot be canceled, inactive_task_timer() |
209a0cbd LA |
389 | * will see that dl_not_contending is not set, and |
390 | * will not touch the rq's active utilization, | |
391 | * so we are still safe. | |
392 | */ | |
393 | if (hrtimer_try_to_cancel(&dl_se->inactive_timer) == 1) | |
394 | put_task_struct(dl_task_of(dl_se)); | |
395 | } else { | |
396 | /* | |
397 | * Since "dl_non_contending" is not set, the | |
398 | * task's utilization has already been removed from | |
399 | * active utilization (either when the task blocked, | |
400 | * when the "inactive timer" fired). | |
401 | * So, add it back. | |
402 | */ | |
794a56eb | 403 | add_running_bw(dl_se, dl_rq); |
209a0cbd LA |
404 | } |
405 | } | |
406 | ||
aab03e05 DF |
407 | static inline int is_leftmost(struct task_struct *p, struct dl_rq *dl_rq) |
408 | { | |
409 | struct sched_dl_entity *dl_se = &p->dl; | |
410 | ||
2161573e | 411 | return dl_rq->root.rb_leftmost == &dl_se->rb_node; |
aab03e05 DF |
412 | } |
413 | ||
ba4f7bc1 YC |
414 | static void init_dl_rq_bw_ratio(struct dl_rq *dl_rq); |
415 | ||
332ac17e DF |
416 | void init_dl_bandwidth(struct dl_bandwidth *dl_b, u64 period, u64 runtime) |
417 | { | |
418 | raw_spin_lock_init(&dl_b->dl_runtime_lock); | |
419 | dl_b->dl_period = period; | |
420 | dl_b->dl_runtime = runtime; | |
421 | } | |
422 | ||
332ac17e DF |
423 | void init_dl_bw(struct dl_bw *dl_b) |
424 | { | |
425 | raw_spin_lock_init(&dl_b->lock); | |
426 | raw_spin_lock(&def_dl_bandwidth.dl_runtime_lock); | |
1724813d | 427 | if (global_rt_runtime() == RUNTIME_INF) |
332ac17e DF |
428 | dl_b->bw = -1; |
429 | else | |
1724813d | 430 | dl_b->bw = to_ratio(global_rt_period(), global_rt_runtime()); |
332ac17e DF |
431 | raw_spin_unlock(&def_dl_bandwidth.dl_runtime_lock); |
432 | dl_b->total_bw = 0; | |
433 | } | |
434 | ||
07c54f7a | 435 | void init_dl_rq(struct dl_rq *dl_rq) |
aab03e05 | 436 | { |
2161573e | 437 | dl_rq->root = RB_ROOT_CACHED; |
1baca4ce JL |
438 | |
439 | #ifdef CONFIG_SMP | |
440 | /* zero means no -deadline tasks */ | |
441 | dl_rq->earliest_dl.curr = dl_rq->earliest_dl.next = 0; | |
442 | ||
443 | dl_rq->dl_nr_migratory = 0; | |
444 | dl_rq->overloaded = 0; | |
2161573e | 445 | dl_rq->pushable_dl_tasks_root = RB_ROOT_CACHED; |
332ac17e DF |
446 | #else |
447 | init_dl_bw(&dl_rq->dl_bw); | |
1baca4ce | 448 | #endif |
e36d8677 LA |
449 | |
450 | dl_rq->running_bw = 0; | |
8fd27231 | 451 | dl_rq->this_bw = 0; |
4da3abce | 452 | init_dl_rq_bw_ratio(dl_rq); |
1baca4ce JL |
453 | } |
454 | ||
455 | #ifdef CONFIG_SMP | |
456 | ||
457 | static inline int dl_overloaded(struct rq *rq) | |
458 | { | |
459 | return atomic_read(&rq->rd->dlo_count); | |
460 | } | |
461 | ||
462 | static inline void dl_set_overload(struct rq *rq) | |
463 | { | |
464 | if (!rq->online) | |
465 | return; | |
466 | ||
467 | cpumask_set_cpu(rq->cpu, rq->rd->dlo_mask); | |
468 | /* | |
469 | * Must be visible before the overload count is | |
470 | * set (as in sched_rt.c). | |
471 | * | |
472 | * Matched by the barrier in pull_dl_task(). | |
473 | */ | |
474 | smp_wmb(); | |
475 | atomic_inc(&rq->rd->dlo_count); | |
476 | } | |
477 | ||
478 | static inline void dl_clear_overload(struct rq *rq) | |
479 | { | |
480 | if (!rq->online) | |
481 | return; | |
482 | ||
483 | atomic_dec(&rq->rd->dlo_count); | |
484 | cpumask_clear_cpu(rq->cpu, rq->rd->dlo_mask); | |
485 | } | |
486 | ||
487 | static void update_dl_migration(struct dl_rq *dl_rq) | |
488 | { | |
995b9ea4 | 489 | if (dl_rq->dl_nr_migratory && dl_rq->dl_nr_running > 1) { |
1baca4ce JL |
490 | if (!dl_rq->overloaded) { |
491 | dl_set_overload(rq_of_dl_rq(dl_rq)); | |
492 | dl_rq->overloaded = 1; | |
493 | } | |
494 | } else if (dl_rq->overloaded) { | |
495 | dl_clear_overload(rq_of_dl_rq(dl_rq)); | |
496 | dl_rq->overloaded = 0; | |
497 | } | |
498 | } | |
499 | ||
500 | static void inc_dl_migration(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq) | |
501 | { | |
502 | struct task_struct *p = dl_task_of(dl_se); | |
1baca4ce | 503 | |
4b53a341 | 504 | if (p->nr_cpus_allowed > 1) |
1baca4ce JL |
505 | dl_rq->dl_nr_migratory++; |
506 | ||
507 | update_dl_migration(dl_rq); | |
508 | } | |
509 | ||
510 | static void dec_dl_migration(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq) | |
511 | { | |
512 | struct task_struct *p = dl_task_of(dl_se); | |
1baca4ce | 513 | |
4b53a341 | 514 | if (p->nr_cpus_allowed > 1) |
1baca4ce JL |
515 | dl_rq->dl_nr_migratory--; |
516 | ||
517 | update_dl_migration(dl_rq); | |
518 | } | |
519 | ||
8ecca394 PZ |
520 | #define __node_2_pdl(node) \ |
521 | rb_entry((node), struct task_struct, pushable_dl_tasks) | |
522 | ||
523 | static inline bool __pushable_less(struct rb_node *a, const struct rb_node *b) | |
524 | { | |
525 | return dl_entity_preempt(&__node_2_pdl(a)->dl, &__node_2_pdl(b)->dl); | |
526 | } | |
527 | ||
1baca4ce JL |
528 | /* |
529 | * The list of pushable -deadline task is not a plist, like in | |
530 | * sched_rt.c, it is an rb-tree with tasks ordered by deadline. | |
531 | */ | |
532 | static void enqueue_pushable_dl_task(struct rq *rq, struct task_struct *p) | |
533 | { | |
8ecca394 | 534 | struct rb_node *leftmost; |
1baca4ce JL |
535 | |
536 | BUG_ON(!RB_EMPTY_NODE(&p->pushable_dl_tasks)); | |
537 | ||
8ecca394 PZ |
538 | leftmost = rb_add_cached(&p->pushable_dl_tasks, |
539 | &rq->dl.pushable_dl_tasks_root, | |
540 | __pushable_less); | |
2161573e | 541 | if (leftmost) |
8ecca394 | 542 | rq->dl.earliest_dl.next = p->dl.deadline; |
aab03e05 DF |
543 | } |
544 | ||
1baca4ce JL |
545 | static void dequeue_pushable_dl_task(struct rq *rq, struct task_struct *p) |
546 | { | |
547 | struct dl_rq *dl_rq = &rq->dl; | |
8ecca394 PZ |
548 | struct rb_root_cached *root = &dl_rq->pushable_dl_tasks_root; |
549 | struct rb_node *leftmost; | |
1baca4ce JL |
550 | |
551 | if (RB_EMPTY_NODE(&p->pushable_dl_tasks)) | |
552 | return; | |
553 | ||
8ecca394 PZ |
554 | leftmost = rb_erase_cached(&p->pushable_dl_tasks, root); |
555 | if (leftmost) | |
556 | dl_rq->earliest_dl.next = __node_2_pdl(leftmost)->dl.deadline; | |
1baca4ce | 557 | |
1baca4ce JL |
558 | RB_CLEAR_NODE(&p->pushable_dl_tasks); |
559 | } | |
560 | ||
561 | static inline int has_pushable_dl_tasks(struct rq *rq) | |
562 | { | |
2161573e | 563 | return !RB_EMPTY_ROOT(&rq->dl.pushable_dl_tasks_root.rb_root); |
1baca4ce JL |
564 | } |
565 | ||
566 | static int push_dl_task(struct rq *rq); | |
567 | ||
dc877341 PZ |
568 | static inline bool need_pull_dl_task(struct rq *rq, struct task_struct *prev) |
569 | { | |
120455c5 | 570 | return rq->online && dl_task(prev); |
dc877341 PZ |
571 | } |
572 | ||
9916e214 PZ |
573 | static DEFINE_PER_CPU(struct callback_head, dl_push_head); |
574 | static DEFINE_PER_CPU(struct callback_head, dl_pull_head); | |
e3fca9e7 PZ |
575 | |
576 | static void push_dl_tasks(struct rq *); | |
9916e214 | 577 | static void pull_dl_task(struct rq *); |
e3fca9e7 | 578 | |
02d8ec94 | 579 | static inline void deadline_queue_push_tasks(struct rq *rq) |
dc877341 | 580 | { |
e3fca9e7 PZ |
581 | if (!has_pushable_dl_tasks(rq)) |
582 | return; | |
583 | ||
9916e214 PZ |
584 | queue_balance_callback(rq, &per_cpu(dl_push_head, rq->cpu), push_dl_tasks); |
585 | } | |
586 | ||
02d8ec94 | 587 | static inline void deadline_queue_pull_task(struct rq *rq) |
9916e214 PZ |
588 | { |
589 | queue_balance_callback(rq, &per_cpu(dl_pull_head, rq->cpu), pull_dl_task); | |
dc877341 PZ |
590 | } |
591 | ||
fa9c9d10 WL |
592 | static struct rq *find_lock_later_rq(struct task_struct *task, struct rq *rq); |
593 | ||
a649f237 | 594 | static struct rq *dl_task_offline_migration(struct rq *rq, struct task_struct *p) |
fa9c9d10 WL |
595 | { |
596 | struct rq *later_rq = NULL; | |
59d06cea | 597 | struct dl_bw *dl_b; |
fa9c9d10 WL |
598 | |
599 | later_rq = find_lock_later_rq(p, rq); | |
fa9c9d10 WL |
600 | if (!later_rq) { |
601 | int cpu; | |
602 | ||
603 | /* | |
604 | * If we cannot preempt any rq, fall back to pick any | |
97fb7a0a | 605 | * online CPU: |
fa9c9d10 | 606 | */ |
3bd37062 | 607 | cpu = cpumask_any_and(cpu_active_mask, p->cpus_ptr); |
fa9c9d10 WL |
608 | if (cpu >= nr_cpu_ids) { |
609 | /* | |
97fb7a0a | 610 | * Failed to find any suitable CPU. |
fa9c9d10 WL |
611 | * The task will never come back! |
612 | */ | |
613 | BUG_ON(dl_bandwidth_enabled()); | |
614 | ||
615 | /* | |
616 | * If admission control is disabled we | |
617 | * try a little harder to let the task | |
618 | * run. | |
619 | */ | |
620 | cpu = cpumask_any(cpu_active_mask); | |
621 | } | |
622 | later_rq = cpu_rq(cpu); | |
623 | double_lock_balance(rq, later_rq); | |
624 | } | |
625 | ||
59d06cea JL |
626 | if (p->dl.dl_non_contending || p->dl.dl_throttled) { |
627 | /* | |
628 | * Inactive timer is armed (or callback is running, but | |
629 | * waiting for us to release rq locks). In any case, when it | |
630 | * will fire (or continue), it will see running_bw of this | |
631 | * task migrated to later_rq (and correctly handle it). | |
632 | */ | |
633 | sub_running_bw(&p->dl, &rq->dl); | |
634 | sub_rq_bw(&p->dl, &rq->dl); | |
635 | ||
636 | add_rq_bw(&p->dl, &later_rq->dl); | |
637 | add_running_bw(&p->dl, &later_rq->dl); | |
638 | } else { | |
639 | sub_rq_bw(&p->dl, &rq->dl); | |
640 | add_rq_bw(&p->dl, &later_rq->dl); | |
641 | } | |
642 | ||
643 | /* | |
644 | * And we finally need to fixup root_domain(s) bandwidth accounting, | |
645 | * since p is still hanging out in the old (now moved to default) root | |
646 | * domain. | |
647 | */ | |
648 | dl_b = &rq->rd->dl_bw; | |
649 | raw_spin_lock(&dl_b->lock); | |
650 | __dl_sub(dl_b, p->dl.dl_bw, cpumask_weight(rq->rd->span)); | |
651 | raw_spin_unlock(&dl_b->lock); | |
652 | ||
653 | dl_b = &later_rq->rd->dl_bw; | |
654 | raw_spin_lock(&dl_b->lock); | |
655 | __dl_add(dl_b, p->dl.dl_bw, cpumask_weight(later_rq->rd->span)); | |
656 | raw_spin_unlock(&dl_b->lock); | |
657 | ||
fa9c9d10 | 658 | set_task_cpu(p, later_rq->cpu); |
a649f237 PZ |
659 | double_unlock_balance(later_rq, rq); |
660 | ||
661 | return later_rq; | |
fa9c9d10 WL |
662 | } |
663 | ||
1baca4ce JL |
664 | #else |
665 | ||
666 | static inline | |
667 | void enqueue_pushable_dl_task(struct rq *rq, struct task_struct *p) | |
668 | { | |
669 | } | |
670 | ||
671 | static inline | |
672 | void dequeue_pushable_dl_task(struct rq *rq, struct task_struct *p) | |
673 | { | |
674 | } | |
675 | ||
676 | static inline | |
677 | void inc_dl_migration(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq) | |
678 | { | |
679 | } | |
680 | ||
681 | static inline | |
682 | void dec_dl_migration(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq) | |
683 | { | |
684 | } | |
685 | ||
dc877341 PZ |
686 | static inline bool need_pull_dl_task(struct rq *rq, struct task_struct *prev) |
687 | { | |
688 | return false; | |
689 | } | |
690 | ||
0ea60c20 | 691 | static inline void pull_dl_task(struct rq *rq) |
dc877341 | 692 | { |
dc877341 PZ |
693 | } |
694 | ||
02d8ec94 | 695 | static inline void deadline_queue_push_tasks(struct rq *rq) |
dc877341 | 696 | { |
dc877341 PZ |
697 | } |
698 | ||
02d8ec94 | 699 | static inline void deadline_queue_pull_task(struct rq *rq) |
dc877341 PZ |
700 | { |
701 | } | |
1baca4ce JL |
702 | #endif /* CONFIG_SMP */ |
703 | ||
aab03e05 DF |
704 | static void enqueue_task_dl(struct rq *rq, struct task_struct *p, int flags); |
705 | static void __dequeue_task_dl(struct rq *rq, struct task_struct *p, int flags); | |
97fb7a0a | 706 | static void check_preempt_curr_dl(struct rq *rq, struct task_struct *p, int flags); |
aab03e05 DF |
707 | |
708 | /* | |
709 | * We are being explicitly informed that a new instance is starting, | |
710 | * and this means that: | |
711 | * - the absolute deadline of the entity has to be placed at | |
712 | * current time + relative deadline; | |
713 | * - the runtime of the entity has to be set to the maximum value. | |
714 | * | |
715 | * The capability of specifying such event is useful whenever a -deadline | |
716 | * entity wants to (try to!) synchronize its behaviour with the scheduler's | |
717 | * one, and to (try to!) reconcile itself with its own scheduling | |
718 | * parameters. | |
719 | */ | |
98b0a857 | 720 | static inline void setup_new_dl_entity(struct sched_dl_entity *dl_se) |
aab03e05 DF |
721 | { |
722 | struct dl_rq *dl_rq = dl_rq_of_se(dl_se); | |
723 | struct rq *rq = rq_of_dl_rq(dl_rq); | |
724 | ||
2279f540 | 725 | WARN_ON(is_dl_boosted(dl_se)); |
72f9f3fd LA |
726 | WARN_ON(dl_time_before(rq_clock(rq), dl_se->deadline)); |
727 | ||
728 | /* | |
729 | * We are racing with the deadline timer. So, do nothing because | |
730 | * the deadline timer handler will take care of properly recharging | |
731 | * the runtime and postponing the deadline | |
732 | */ | |
733 | if (dl_se->dl_throttled) | |
734 | return; | |
aab03e05 DF |
735 | |
736 | /* | |
737 | * We use the regular wall clock time to set deadlines in the | |
738 | * future; in fact, we must consider execution overheads (time | |
739 | * spent on hardirq context, etc.). | |
740 | */ | |
98b0a857 JL |
741 | dl_se->deadline = rq_clock(rq) + dl_se->dl_deadline; |
742 | dl_se->runtime = dl_se->dl_runtime; | |
aab03e05 DF |
743 | } |
744 | ||
745 | /* | |
746 | * Pure Earliest Deadline First (EDF) scheduling does not deal with the | |
747 | * possibility of a entity lasting more than what it declared, and thus | |
748 | * exhausting its runtime. | |
749 | * | |
750 | * Here we are interested in making runtime overrun possible, but we do | |
751 | * not want a entity which is misbehaving to affect the scheduling of all | |
752 | * other entities. | |
753 | * Therefore, a budgeting strategy called Constant Bandwidth Server (CBS) | |
754 | * is used, in order to confine each entity within its own bandwidth. | |
755 | * | |
756 | * This function deals exactly with that, and ensures that when the runtime | |
757 | * of a entity is replenished, its deadline is also postponed. That ensures | |
758 | * the overrunning entity can't interfere with other entity in the system and | |
759 | * can't make them miss their deadlines. Reasons why this kind of overruns | |
760 | * could happen are, typically, a entity voluntarily trying to overcome its | |
1b09d29b | 761 | * runtime, or it just underestimated it during sched_setattr(). |
aab03e05 | 762 | */ |
2279f540 | 763 | static void replenish_dl_entity(struct sched_dl_entity *dl_se) |
aab03e05 DF |
764 | { |
765 | struct dl_rq *dl_rq = dl_rq_of_se(dl_se); | |
766 | struct rq *rq = rq_of_dl_rq(dl_rq); | |
767 | ||
2279f540 | 768 | BUG_ON(pi_of(dl_se)->dl_runtime <= 0); |
2d3d891d DF |
769 | |
770 | /* | |
771 | * This could be the case for a !-dl task that is boosted. | |
772 | * Just go with full inherited parameters. | |
773 | */ | |
774 | if (dl_se->dl_deadline == 0) { | |
2279f540 JL |
775 | dl_se->deadline = rq_clock(rq) + pi_of(dl_se)->dl_deadline; |
776 | dl_se->runtime = pi_of(dl_se)->dl_runtime; | |
2d3d891d DF |
777 | } |
778 | ||
48be3a67 PZ |
779 | if (dl_se->dl_yielded && dl_se->runtime > 0) |
780 | dl_se->runtime = 0; | |
781 | ||
aab03e05 DF |
782 | /* |
783 | * We keep moving the deadline away until we get some | |
784 | * available runtime for the entity. This ensures correct | |
785 | * handling of situations where the runtime overrun is | |
786 | * arbitrary large. | |
787 | */ | |
788 | while (dl_se->runtime <= 0) { | |
2279f540 JL |
789 | dl_se->deadline += pi_of(dl_se)->dl_period; |
790 | dl_se->runtime += pi_of(dl_se)->dl_runtime; | |
aab03e05 DF |
791 | } |
792 | ||
793 | /* | |
794 | * At this point, the deadline really should be "in | |
795 | * the future" with respect to rq->clock. If it's | |
796 | * not, we are, for some reason, lagging too much! | |
797 | * Anyway, after having warn userspace abut that, | |
798 | * we still try to keep the things running by | |
799 | * resetting the deadline and the budget of the | |
800 | * entity. | |
801 | */ | |
802 | if (dl_time_before(dl_se->deadline, rq_clock(rq))) { | |
c219b7dd | 803 | printk_deferred_once("sched: DL replenish lagged too much\n"); |
2279f540 JL |
804 | dl_se->deadline = rq_clock(rq) + pi_of(dl_se)->dl_deadline; |
805 | dl_se->runtime = pi_of(dl_se)->dl_runtime; | |
aab03e05 | 806 | } |
1019a359 PZ |
807 | |
808 | if (dl_se->dl_yielded) | |
809 | dl_se->dl_yielded = 0; | |
810 | if (dl_se->dl_throttled) | |
811 | dl_se->dl_throttled = 0; | |
aab03e05 DF |
812 | } |
813 | ||
814 | /* | |
815 | * Here we check if --at time t-- an entity (which is probably being | |
816 | * [re]activated or, in general, enqueued) can use its remaining runtime | |
817 | * and its current deadline _without_ exceeding the bandwidth it is | |
818 | * assigned (function returns true if it can't). We are in fact applying | |
819 | * one of the CBS rules: when a task wakes up, if the residual runtime | |
820 | * over residual deadline fits within the allocated bandwidth, then we | |
821 | * can keep the current (absolute) deadline and residual budget without | |
822 | * disrupting the schedulability of the system. Otherwise, we should | |
823 | * refill the runtime and set the deadline a period in the future, | |
824 | * because keeping the current (absolute) deadline of the task would | |
712e5e34 | 825 | * result in breaking guarantees promised to other tasks (refer to |
d6a3b247 | 826 | * Documentation/scheduler/sched-deadline.rst for more information). |
aab03e05 DF |
827 | * |
828 | * This function returns true if: | |
829 | * | |
2317d5f1 | 830 | * runtime / (deadline - t) > dl_runtime / dl_deadline , |
aab03e05 DF |
831 | * |
832 | * IOW we can't recycle current parameters. | |
755378a4 | 833 | * |
2317d5f1 | 834 | * Notice that the bandwidth check is done against the deadline. For |
755378a4 | 835 | * task with deadline equal to period this is the same of using |
2317d5f1 | 836 | * dl_period instead of dl_deadline in the equation above. |
aab03e05 | 837 | */ |
2279f540 | 838 | static bool dl_entity_overflow(struct sched_dl_entity *dl_se, u64 t) |
aab03e05 DF |
839 | { |
840 | u64 left, right; | |
841 | ||
842 | /* | |
843 | * left and right are the two sides of the equation above, | |
844 | * after a bit of shuffling to use multiplications instead | |
845 | * of divisions. | |
846 | * | |
847 | * Note that none of the time values involved in the two | |
848 | * multiplications are absolute: dl_deadline and dl_runtime | |
849 | * are the relative deadline and the maximum runtime of each | |
850 | * instance, runtime is the runtime left for the last instance | |
851 | * and (deadline - t), since t is rq->clock, is the time left | |
852 | * to the (absolute) deadline. Even if overflowing the u64 type | |
853 | * is very unlikely to occur in both cases, here we scale down | |
854 | * as we want to avoid that risk at all. Scaling down by 10 | |
855 | * means that we reduce granularity to 1us. We are fine with it, | |
856 | * since this is only a true/false check and, anyway, thinking | |
857 | * of anything below microseconds resolution is actually fiction | |
858 | * (but still we want to give the user that illusion >;). | |
859 | */ | |
2279f540 | 860 | left = (pi_of(dl_se)->dl_deadline >> DL_SCALE) * (dl_se->runtime >> DL_SCALE); |
332ac17e | 861 | right = ((dl_se->deadline - t) >> DL_SCALE) * |
2279f540 | 862 | (pi_of(dl_se)->dl_runtime >> DL_SCALE); |
aab03e05 DF |
863 | |
864 | return dl_time_before(right, left); | |
865 | } | |
866 | ||
867 | /* | |
3effcb42 DBO |
868 | * Revised wakeup rule [1]: For self-suspending tasks, rather then |
869 | * re-initializing task's runtime and deadline, the revised wakeup | |
870 | * rule adjusts the task's runtime to avoid the task to overrun its | |
871 | * density. | |
aab03e05 | 872 | * |
3effcb42 DBO |
873 | * Reasoning: a task may overrun the density if: |
874 | * runtime / (deadline - t) > dl_runtime / dl_deadline | |
875 | * | |
876 | * Therefore, runtime can be adjusted to: | |
877 | * runtime = (dl_runtime / dl_deadline) * (deadline - t) | |
878 | * | |
879 | * In such way that runtime will be equal to the maximum density | |
880 | * the task can use without breaking any rule. | |
881 | * | |
882 | * [1] Luca Abeni, Giuseppe Lipari, and Juri Lelli. 2015. Constant | |
883 | * bandwidth server revisited. SIGBED Rev. 11, 4 (January 2015), 19-24. | |
884 | */ | |
885 | static void | |
886 | update_dl_revised_wakeup(struct sched_dl_entity *dl_se, struct rq *rq) | |
887 | { | |
888 | u64 laxity = dl_se->deadline - rq_clock(rq); | |
889 | ||
890 | /* | |
891 | * If the task has deadline < period, and the deadline is in the past, | |
892 | * it should already be throttled before this check. | |
893 | * | |
894 | * See update_dl_entity() comments for further details. | |
895 | */ | |
896 | WARN_ON(dl_time_before(dl_se->deadline, rq_clock(rq))); | |
897 | ||
898 | dl_se->runtime = (dl_se->dl_density * laxity) >> BW_SHIFT; | |
899 | } | |
900 | ||
901 | /* | |
902 | * Regarding the deadline, a task with implicit deadline has a relative | |
903 | * deadline == relative period. A task with constrained deadline has a | |
904 | * relative deadline <= relative period. | |
905 | * | |
906 | * We support constrained deadline tasks. However, there are some restrictions | |
907 | * applied only for tasks which do not have an implicit deadline. See | |
908 | * update_dl_entity() to know more about such restrictions. | |
909 | * | |
910 | * The dl_is_implicit() returns true if the task has an implicit deadline. | |
911 | */ | |
912 | static inline bool dl_is_implicit(struct sched_dl_entity *dl_se) | |
913 | { | |
914 | return dl_se->dl_deadline == dl_se->dl_period; | |
915 | } | |
916 | ||
917 | /* | |
918 | * When a deadline entity is placed in the runqueue, its runtime and deadline | |
919 | * might need to be updated. This is done by a CBS wake up rule. There are two | |
920 | * different rules: 1) the original CBS; and 2) the Revisited CBS. | |
921 | * | |
922 | * When the task is starting a new period, the Original CBS is used. In this | |
923 | * case, the runtime is replenished and a new absolute deadline is set. | |
924 | * | |
925 | * When a task is queued before the begin of the next period, using the | |
926 | * remaining runtime and deadline could make the entity to overflow, see | |
927 | * dl_entity_overflow() to find more about runtime overflow. When such case | |
928 | * is detected, the runtime and deadline need to be updated. | |
929 | * | |
930 | * If the task has an implicit deadline, i.e., deadline == period, the Original | |
931 | * CBS is applied. the runtime is replenished and a new absolute deadline is | |
932 | * set, as in the previous cases. | |
933 | * | |
934 | * However, the Original CBS does not work properly for tasks with | |
935 | * deadline < period, which are said to have a constrained deadline. By | |
936 | * applying the Original CBS, a constrained deadline task would be able to run | |
937 | * runtime/deadline in a period. With deadline < period, the task would | |
938 | * overrun the runtime/period allowed bandwidth, breaking the admission test. | |
939 | * | |
940 | * In order to prevent this misbehave, the Revisited CBS is used for | |
941 | * constrained deadline tasks when a runtime overflow is detected. In the | |
942 | * Revisited CBS, rather than replenishing & setting a new absolute deadline, | |
943 | * the remaining runtime of the task is reduced to avoid runtime overflow. | |
944 | * Please refer to the comments update_dl_revised_wakeup() function to find | |
945 | * more about the Revised CBS rule. | |
aab03e05 | 946 | */ |
2279f540 | 947 | static void update_dl_entity(struct sched_dl_entity *dl_se) |
aab03e05 DF |
948 | { |
949 | struct dl_rq *dl_rq = dl_rq_of_se(dl_se); | |
950 | struct rq *rq = rq_of_dl_rq(dl_rq); | |
951 | ||
aab03e05 | 952 | if (dl_time_before(dl_se->deadline, rq_clock(rq)) || |
2279f540 | 953 | dl_entity_overflow(dl_se, rq_clock(rq))) { |
3effcb42 DBO |
954 | |
955 | if (unlikely(!dl_is_implicit(dl_se) && | |
956 | !dl_time_before(dl_se->deadline, rq_clock(rq)) && | |
2279f540 | 957 | !is_dl_boosted(dl_se))) { |
3effcb42 DBO |
958 | update_dl_revised_wakeup(dl_se, rq); |
959 | return; | |
960 | } | |
961 | ||
2279f540 JL |
962 | dl_se->deadline = rq_clock(rq) + pi_of(dl_se)->dl_deadline; |
963 | dl_se->runtime = pi_of(dl_se)->dl_runtime; | |
aab03e05 DF |
964 | } |
965 | } | |
966 | ||
5ac69d37 DBO |
967 | static inline u64 dl_next_period(struct sched_dl_entity *dl_se) |
968 | { | |
969 | return dl_se->deadline - dl_se->dl_deadline + dl_se->dl_period; | |
970 | } | |
971 | ||
aab03e05 DF |
972 | /* |
973 | * If the entity depleted all its runtime, and if we want it to sleep | |
974 | * while waiting for some new execution time to become available, we | |
5ac69d37 | 975 | * set the bandwidth replenishment timer to the replenishment instant |
aab03e05 DF |
976 | * and try to activate it. |
977 | * | |
978 | * Notice that it is important for the caller to know if the timer | |
979 | * actually started or not (i.e., the replenishment instant is in | |
980 | * the future or in the past). | |
981 | */ | |
a649f237 | 982 | static int start_dl_timer(struct task_struct *p) |
aab03e05 | 983 | { |
a649f237 PZ |
984 | struct sched_dl_entity *dl_se = &p->dl; |
985 | struct hrtimer *timer = &dl_se->dl_timer; | |
986 | struct rq *rq = task_rq(p); | |
aab03e05 | 987 | ktime_t now, act; |
aab03e05 DF |
988 | s64 delta; |
989 | ||
5cb9eaa3 | 990 | lockdep_assert_rq_held(rq); |
a649f237 | 991 | |
aab03e05 DF |
992 | /* |
993 | * We want the timer to fire at the deadline, but considering | |
994 | * that it is actually coming from rq->clock and not from | |
995 | * hrtimer's time base reading. | |
996 | */ | |
5ac69d37 | 997 | act = ns_to_ktime(dl_next_period(dl_se)); |
a649f237 | 998 | now = hrtimer_cb_get_time(timer); |
aab03e05 DF |
999 | delta = ktime_to_ns(now) - rq_clock(rq); |
1000 | act = ktime_add_ns(act, delta); | |
1001 | ||
1002 | /* | |
1003 | * If the expiry time already passed, e.g., because the value | |
1004 | * chosen as the deadline is too small, don't even try to | |
1005 | * start the timer in the past! | |
1006 | */ | |
1007 | if (ktime_us_delta(act, now) < 0) | |
1008 | return 0; | |
1009 | ||
a649f237 PZ |
1010 | /* |
1011 | * !enqueued will guarantee another callback; even if one is already in | |
1012 | * progress. This ensures a balanced {get,put}_task_struct(). | |
1013 | * | |
1014 | * The race against __run_timer() clearing the enqueued state is | |
1015 | * harmless because we're holding task_rq()->lock, therefore the timer | |
1016 | * expiring after we've done the check will wait on its task_rq_lock() | |
1017 | * and observe our state. | |
1018 | */ | |
1019 | if (!hrtimer_is_queued(timer)) { | |
1020 | get_task_struct(p); | |
d5096aa6 | 1021 | hrtimer_start(timer, act, HRTIMER_MODE_ABS_HARD); |
a649f237 | 1022 | } |
aab03e05 | 1023 | |
cc9684d3 | 1024 | return 1; |
aab03e05 DF |
1025 | } |
1026 | ||
1027 | /* | |
1028 | * This is the bandwidth enforcement timer callback. If here, we know | |
1029 | * a task is not on its dl_rq, since the fact that the timer was running | |
1030 | * means the task is throttled and needs a runtime replenishment. | |
1031 | * | |
1032 | * However, what we actually do depends on the fact the task is active, | |
1033 | * (it is on its rq) or has been removed from there by a call to | |
1034 | * dequeue_task_dl(). In the former case we must issue the runtime | |
1035 | * replenishment and add the task back to the dl_rq; in the latter, we just | |
1036 | * do nothing but clearing dl_throttled, so that runtime and deadline | |
1037 | * updating (and the queueing back to dl_rq) will be done by the | |
1038 | * next call to enqueue_task_dl(). | |
1039 | */ | |
1040 | static enum hrtimer_restart dl_task_timer(struct hrtimer *timer) | |
1041 | { | |
1042 | struct sched_dl_entity *dl_se = container_of(timer, | |
1043 | struct sched_dl_entity, | |
1044 | dl_timer); | |
1045 | struct task_struct *p = dl_task_of(dl_se); | |
eb580751 | 1046 | struct rq_flags rf; |
0f397f2c | 1047 | struct rq *rq; |
3960c8c0 | 1048 | |
eb580751 | 1049 | rq = task_rq_lock(p, &rf); |
0f397f2c | 1050 | |
aab03e05 | 1051 | /* |
a649f237 | 1052 | * The task might have changed its scheduling policy to something |
9846d50d | 1053 | * different than SCHED_DEADLINE (through switched_from_dl()). |
a649f237 | 1054 | */ |
209a0cbd | 1055 | if (!dl_task(p)) |
a649f237 | 1056 | goto unlock; |
a649f237 | 1057 | |
a649f237 PZ |
1058 | /* |
1059 | * The task might have been boosted by someone else and might be in the | |
1060 | * boosting/deboosting path, its not throttled. | |
1061 | */ | |
2279f540 | 1062 | if (is_dl_boosted(dl_se)) |
a649f237 | 1063 | goto unlock; |
a79ec89f | 1064 | |
fa9c9d10 | 1065 | /* |
a649f237 PZ |
1066 | * Spurious timer due to start_dl_timer() race; or we already received |
1067 | * a replenishment from rt_mutex_setprio(). | |
fa9c9d10 | 1068 | */ |
a649f237 | 1069 | if (!dl_se->dl_throttled) |
fa9c9d10 | 1070 | goto unlock; |
a649f237 PZ |
1071 | |
1072 | sched_clock_tick(); | |
1073 | update_rq_clock(rq); | |
fa9c9d10 | 1074 | |
a79ec89f KT |
1075 | /* |
1076 | * If the throttle happened during sched-out; like: | |
1077 | * | |
1078 | * schedule() | |
1079 | * deactivate_task() | |
1080 | * dequeue_task_dl() | |
1081 | * update_curr_dl() | |
1082 | * start_dl_timer() | |
1083 | * __dequeue_task_dl() | |
1084 | * prev->on_rq = 0; | |
1085 | * | |
1086 | * We can be both throttled and !queued. Replenish the counter | |
1087 | * but do not enqueue -- wait for our wakeup to do that. | |
1088 | */ | |
1089 | if (!task_on_rq_queued(p)) { | |
2279f540 | 1090 | replenish_dl_entity(dl_se); |
a79ec89f KT |
1091 | goto unlock; |
1092 | } | |
1093 | ||
1baca4ce | 1094 | #ifdef CONFIG_SMP |
c0c8c9fa | 1095 | if (unlikely(!rq->online)) { |
61c7aca6 WL |
1096 | /* |
1097 | * If the runqueue is no longer available, migrate the | |
1098 | * task elsewhere. This necessarily changes rq. | |
1099 | */ | |
9ef7e7e3 | 1100 | lockdep_unpin_lock(__rq_lockp(rq), rf.cookie); |
a649f237 | 1101 | rq = dl_task_offline_migration(rq, p); |
9ef7e7e3 | 1102 | rf.cookie = lockdep_pin_lock(__rq_lockp(rq)); |
dcc3b5ff | 1103 | update_rq_clock(rq); |
61c7aca6 WL |
1104 | |
1105 | /* | |
1106 | * Now that the task has been migrated to the new RQ and we | |
1107 | * have that locked, proceed as normal and enqueue the task | |
1108 | * there. | |
1109 | */ | |
c0c8c9fa | 1110 | } |
61c7aca6 | 1111 | #endif |
a649f237 | 1112 | |
61c7aca6 WL |
1113 | enqueue_task_dl(rq, p, ENQUEUE_REPLENISH); |
1114 | if (dl_task(rq->curr)) | |
1115 | check_preempt_curr_dl(rq, p, 0); | |
1116 | else | |
1117 | resched_curr(rq); | |
a649f237 | 1118 | |
61c7aca6 | 1119 | #ifdef CONFIG_SMP |
a649f237 PZ |
1120 | /* |
1121 | * Queueing this task back might have overloaded rq, check if we need | |
1122 | * to kick someone away. | |
1019a359 | 1123 | */ |
0aaafaab PZ |
1124 | if (has_pushable_dl_tasks(rq)) { |
1125 | /* | |
1126 | * Nothing relies on rq->lock after this, so its safe to drop | |
1127 | * rq->lock. | |
1128 | */ | |
d8ac8971 | 1129 | rq_unpin_lock(rq, &rf); |
1019a359 | 1130 | push_dl_task(rq); |
d8ac8971 | 1131 | rq_repin_lock(rq, &rf); |
0aaafaab | 1132 | } |
1baca4ce | 1133 | #endif |
a649f237 | 1134 | |
aab03e05 | 1135 | unlock: |
eb580751 | 1136 | task_rq_unlock(rq, p, &rf); |
aab03e05 | 1137 | |
a649f237 PZ |
1138 | /* |
1139 | * This can free the task_struct, including this hrtimer, do not touch | |
1140 | * anything related to that after this. | |
1141 | */ | |
1142 | put_task_struct(p); | |
1143 | ||
aab03e05 DF |
1144 | return HRTIMER_NORESTART; |
1145 | } | |
1146 | ||
1147 | void init_dl_task_timer(struct sched_dl_entity *dl_se) | |
1148 | { | |
1149 | struct hrtimer *timer = &dl_se->dl_timer; | |
1150 | ||
d5096aa6 | 1151 | hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD); |
aab03e05 DF |
1152 | timer->function = dl_task_timer; |
1153 | } | |
1154 | ||
df8eac8c DBO |
1155 | /* |
1156 | * During the activation, CBS checks if it can reuse the current task's | |
1157 | * runtime and period. If the deadline of the task is in the past, CBS | |
1158 | * cannot use the runtime, and so it replenishes the task. This rule | |
1159 | * works fine for implicit deadline tasks (deadline == period), and the | |
1160 | * CBS was designed for implicit deadline tasks. However, a task with | |
c4969417 | 1161 | * constrained deadline (deadline < period) might be awakened after the |
df8eac8c DBO |
1162 | * deadline, but before the next period. In this case, replenishing the |
1163 | * task would allow it to run for runtime / deadline. As in this case | |
1164 | * deadline < period, CBS enables a task to run for more than the | |
1165 | * runtime / period. In a very loaded system, this can cause a domino | |
1166 | * effect, making other tasks miss their deadlines. | |
1167 | * | |
1168 | * To avoid this problem, in the activation of a constrained deadline | |
1169 | * task after the deadline but before the next period, throttle the | |
1170 | * task and set the replenishing timer to the begin of the next period, | |
1171 | * unless it is boosted. | |
1172 | */ | |
1173 | static inline void dl_check_constrained_dl(struct sched_dl_entity *dl_se) | |
1174 | { | |
1175 | struct task_struct *p = dl_task_of(dl_se); | |
1176 | struct rq *rq = rq_of_dl_rq(dl_rq_of_se(dl_se)); | |
1177 | ||
1178 | if (dl_time_before(dl_se->deadline, rq_clock(rq)) && | |
1179 | dl_time_before(rq_clock(rq), dl_next_period(dl_se))) { | |
2279f540 | 1180 | if (unlikely(is_dl_boosted(dl_se) || !start_dl_timer(p))) |
df8eac8c DBO |
1181 | return; |
1182 | dl_se->dl_throttled = 1; | |
ae83b56a XP |
1183 | if (dl_se->runtime > 0) |
1184 | dl_se->runtime = 0; | |
df8eac8c DBO |
1185 | } |
1186 | } | |
1187 | ||
aab03e05 | 1188 | static |
6fab5410 | 1189 | int dl_runtime_exceeded(struct sched_dl_entity *dl_se) |
aab03e05 | 1190 | { |
269ad801 | 1191 | return (dl_se->runtime <= 0); |
aab03e05 DF |
1192 | } |
1193 | ||
faa59937 JL |
1194 | extern bool sched_rt_bandwidth_account(struct rt_rq *rt_rq); |
1195 | ||
c52f14d3 LA |
1196 | /* |
1197 | * This function implements the GRUB accounting rule: | |
1198 | * according to the GRUB reclaiming algorithm, the runtime is | |
daec5798 LA |
1199 | * not decreased as "dq = -dt", but as |
1200 | * "dq = -max{u / Umax, (1 - Uinact - Uextra)} dt", | |
1201 | * where u is the utilization of the task, Umax is the maximum reclaimable | |
1202 | * utilization, Uinact is the (per-runqueue) inactive utilization, computed | |
1203 | * as the difference between the "total runqueue utilization" and the | |
1204 | * runqueue active utilization, and Uextra is the (per runqueue) extra | |
1205 | * reclaimable utilization. | |
9f0d1a50 | 1206 | * Since rq->dl.running_bw and rq->dl.this_bw contain utilizations |
daec5798 LA |
1207 | * multiplied by 2^BW_SHIFT, the result has to be shifted right by |
1208 | * BW_SHIFT. | |
3b03706f | 1209 | * Since rq->dl.bw_ratio contains 1 / Umax multiplied by 2^RATIO_SHIFT, |
daec5798 LA |
1210 | * dl_bw is multiped by rq->dl.bw_ratio and shifted right by RATIO_SHIFT. |
1211 | * Since delta is a 64 bit variable, to have an overflow its value | |
1212 | * should be larger than 2^(64 - 20 - 8), which is more than 64 seconds. | |
1213 | * So, overflow is not an issue here. | |
c52f14d3 | 1214 | */ |
3febfc8a | 1215 | static u64 grub_reclaim(u64 delta, struct rq *rq, struct sched_dl_entity *dl_se) |
c52f14d3 | 1216 | { |
9f0d1a50 LA |
1217 | u64 u_inact = rq->dl.this_bw - rq->dl.running_bw; /* Utot - Uact */ |
1218 | u64 u_act; | |
daec5798 | 1219 | u64 u_act_min = (dl_se->dl_bw * rq->dl.bw_ratio) >> RATIO_SHIFT; |
c52f14d3 | 1220 | |
9f0d1a50 | 1221 | /* |
daec5798 LA |
1222 | * Instead of computing max{u * bw_ratio, (1 - u_inact - u_extra)}, |
1223 | * we compare u_inact + rq->dl.extra_bw with | |
1224 | * 1 - (u * rq->dl.bw_ratio >> RATIO_SHIFT), because | |
1225 | * u_inact + rq->dl.extra_bw can be larger than | |
1226 | * 1 * (so, 1 - u_inact - rq->dl.extra_bw would be negative | |
1227 | * leading to wrong results) | |
9f0d1a50 | 1228 | */ |
daec5798 LA |
1229 | if (u_inact + rq->dl.extra_bw > BW_UNIT - u_act_min) |
1230 | u_act = u_act_min; | |
9f0d1a50 | 1231 | else |
daec5798 | 1232 | u_act = BW_UNIT - u_inact - rq->dl.extra_bw; |
9f0d1a50 LA |
1233 | |
1234 | return (delta * u_act) >> BW_SHIFT; | |
c52f14d3 LA |
1235 | } |
1236 | ||
aab03e05 DF |
1237 | /* |
1238 | * Update the current task's runtime statistics (provided it is still | |
1239 | * a -deadline task and has not been removed from the dl_rq). | |
1240 | */ | |
1241 | static void update_curr_dl(struct rq *rq) | |
1242 | { | |
1243 | struct task_struct *curr = rq->curr; | |
1244 | struct sched_dl_entity *dl_se = &curr->dl; | |
07881166 JL |
1245 | u64 delta_exec, scaled_delta_exec; |
1246 | int cpu = cpu_of(rq); | |
6fe0ce1e | 1247 | u64 now; |
aab03e05 DF |
1248 | |
1249 | if (!dl_task(curr) || !on_dl_rq(dl_se)) | |
1250 | return; | |
1251 | ||
1252 | /* | |
1253 | * Consumed budget is computed considering the time as | |
1254 | * observed by schedulable tasks (excluding time spent | |
1255 | * in hardirq context, etc.). Deadlines are instead | |
1256 | * computed using hard walltime. This seems to be the more | |
1257 | * natural solution, but the full ramifications of this | |
1258 | * approach need further study. | |
1259 | */ | |
6fe0ce1e WY |
1260 | now = rq_clock_task(rq); |
1261 | delta_exec = now - curr->se.exec_start; | |
48be3a67 PZ |
1262 | if (unlikely((s64)delta_exec <= 0)) { |
1263 | if (unlikely(dl_se->dl_yielded)) | |
1264 | goto throttle; | |
734ff2a7 | 1265 | return; |
48be3a67 | 1266 | } |
aab03e05 DF |
1267 | |
1268 | schedstat_set(curr->se.statistics.exec_max, | |
1269 | max(curr->se.statistics.exec_max, delta_exec)); | |
1270 | ||
1271 | curr->se.sum_exec_runtime += delta_exec; | |
1272 | account_group_exec_runtime(curr, delta_exec); | |
1273 | ||
6fe0ce1e | 1274 | curr->se.exec_start = now; |
d2cc5ed6 | 1275 | cgroup_account_cputime(curr, delta_exec); |
aab03e05 | 1276 | |
794a56eb JL |
1277 | if (dl_entity_is_special(dl_se)) |
1278 | return; | |
1279 | ||
07881166 JL |
1280 | /* |
1281 | * For tasks that participate in GRUB, we implement GRUB-PA: the | |
1282 | * spare reclaimed bandwidth is used to clock down frequency. | |
1283 | * | |
1284 | * For the others, we still need to scale reservation parameters | |
1285 | * according to current frequency and CPU maximum capacity. | |
1286 | */ | |
1287 | if (unlikely(dl_se->flags & SCHED_FLAG_RECLAIM)) { | |
1288 | scaled_delta_exec = grub_reclaim(delta_exec, | |
1289 | rq, | |
1290 | &curr->dl); | |
1291 | } else { | |
1292 | unsigned long scale_freq = arch_scale_freq_capacity(cpu); | |
8ec59c0f | 1293 | unsigned long scale_cpu = arch_scale_cpu_capacity(cpu); |
07881166 JL |
1294 | |
1295 | scaled_delta_exec = cap_scale(delta_exec, scale_freq); | |
1296 | scaled_delta_exec = cap_scale(scaled_delta_exec, scale_cpu); | |
1297 | } | |
1298 | ||
1299 | dl_se->runtime -= scaled_delta_exec; | |
48be3a67 PZ |
1300 | |
1301 | throttle: | |
1302 | if (dl_runtime_exceeded(dl_se) || dl_se->dl_yielded) { | |
1019a359 | 1303 | dl_se->dl_throttled = 1; |
34be3930 JL |
1304 | |
1305 | /* If requested, inform the user about runtime overruns. */ | |
1306 | if (dl_runtime_exceeded(dl_se) && | |
1307 | (dl_se->flags & SCHED_FLAG_DL_OVERRUN)) | |
1308 | dl_se->dl_overrun = 1; | |
1309 | ||
aab03e05 | 1310 | __dequeue_task_dl(rq, curr, 0); |
2279f540 | 1311 | if (unlikely(is_dl_boosted(dl_se) || !start_dl_timer(curr))) |
aab03e05 DF |
1312 | enqueue_task_dl(rq, curr, ENQUEUE_REPLENISH); |
1313 | ||
1314 | if (!is_leftmost(curr, &rq->dl)) | |
8875125e | 1315 | resched_curr(rq); |
aab03e05 | 1316 | } |
1724813d PZ |
1317 | |
1318 | /* | |
1319 | * Because -- for now -- we share the rt bandwidth, we need to | |
1320 | * account our runtime there too, otherwise actual rt tasks | |
1321 | * would be able to exceed the shared quota. | |
1322 | * | |
1323 | * Account to the root rt group for now. | |
1324 | * | |
1325 | * The solution we're working towards is having the RT groups scheduled | |
1326 | * using deadline servers -- however there's a few nasties to figure | |
1327 | * out before that can happen. | |
1328 | */ | |
1329 | if (rt_bandwidth_enabled()) { | |
1330 | struct rt_rq *rt_rq = &rq->rt; | |
1331 | ||
1332 | raw_spin_lock(&rt_rq->rt_runtime_lock); | |
1724813d PZ |
1333 | /* |
1334 | * We'll let actual RT tasks worry about the overflow here, we | |
faa59937 JL |
1335 | * have our own CBS to keep us inline; only account when RT |
1336 | * bandwidth is relevant. | |
1724813d | 1337 | */ |
faa59937 JL |
1338 | if (sched_rt_bandwidth_account(rt_rq)) |
1339 | rt_rq->rt_time += delta_exec; | |
1724813d PZ |
1340 | raw_spin_unlock(&rt_rq->rt_runtime_lock); |
1341 | } | |
aab03e05 DF |
1342 | } |
1343 | ||
209a0cbd LA |
1344 | static enum hrtimer_restart inactive_task_timer(struct hrtimer *timer) |
1345 | { | |
1346 | struct sched_dl_entity *dl_se = container_of(timer, | |
1347 | struct sched_dl_entity, | |
1348 | inactive_timer); | |
1349 | struct task_struct *p = dl_task_of(dl_se); | |
1350 | struct rq_flags rf; | |
1351 | struct rq *rq; | |
1352 | ||
1353 | rq = task_rq_lock(p, &rf); | |
1354 | ||
ecda2b66 JL |
1355 | sched_clock_tick(); |
1356 | update_rq_clock(rq); | |
1357 | ||
2f064a59 | 1358 | if (!dl_task(p) || READ_ONCE(p->__state) == TASK_DEAD) { |
387e3130 LA |
1359 | struct dl_bw *dl_b = dl_bw_of(task_cpu(p)); |
1360 | ||
2f064a59 | 1361 | if (READ_ONCE(p->__state) == TASK_DEAD && dl_se->dl_non_contending) { |
794a56eb JL |
1362 | sub_running_bw(&p->dl, dl_rq_of_se(&p->dl)); |
1363 | sub_rq_bw(&p->dl, dl_rq_of_se(&p->dl)); | |
209a0cbd LA |
1364 | dl_se->dl_non_contending = 0; |
1365 | } | |
387e3130 LA |
1366 | |
1367 | raw_spin_lock(&dl_b->lock); | |
8c0944ce | 1368 | __dl_sub(dl_b, p->dl.dl_bw, dl_bw_cpus(task_cpu(p))); |
387e3130 | 1369 | raw_spin_unlock(&dl_b->lock); |
209a0cbd LA |
1370 | __dl_clear_params(p); |
1371 | ||
1372 | goto unlock; | |
1373 | } | |
1374 | if (dl_se->dl_non_contending == 0) | |
1375 | goto unlock; | |
1376 | ||
794a56eb | 1377 | sub_running_bw(dl_se, &rq->dl); |
209a0cbd LA |
1378 | dl_se->dl_non_contending = 0; |
1379 | unlock: | |
1380 | task_rq_unlock(rq, p, &rf); | |
1381 | put_task_struct(p); | |
1382 | ||
1383 | return HRTIMER_NORESTART; | |
1384 | } | |
1385 | ||
1386 | void init_dl_inactive_task_timer(struct sched_dl_entity *dl_se) | |
1387 | { | |
1388 | struct hrtimer *timer = &dl_se->inactive_timer; | |
1389 | ||
850377a8 | 1390 | hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD); |
209a0cbd LA |
1391 | timer->function = inactive_task_timer; |
1392 | } | |
1393 | ||
1baca4ce JL |
1394 | #ifdef CONFIG_SMP |
1395 | ||
1baca4ce JL |
1396 | static void inc_dl_deadline(struct dl_rq *dl_rq, u64 deadline) |
1397 | { | |
1398 | struct rq *rq = rq_of_dl_rq(dl_rq); | |
1399 | ||
1400 | if (dl_rq->earliest_dl.curr == 0 || | |
1401 | dl_time_before(deadline, dl_rq->earliest_dl.curr)) { | |
b13772f8 PZ |
1402 | if (dl_rq->earliest_dl.curr == 0) |
1403 | cpupri_set(&rq->rd->cpupri, rq->cpu, CPUPRI_HIGHER); | |
1baca4ce | 1404 | dl_rq->earliest_dl.curr = deadline; |
d8206bb3 | 1405 | cpudl_set(&rq->rd->cpudl, rq->cpu, deadline); |
1baca4ce JL |
1406 | } |
1407 | } | |
1408 | ||
1409 | static void dec_dl_deadline(struct dl_rq *dl_rq, u64 deadline) | |
1410 | { | |
1411 | struct rq *rq = rq_of_dl_rq(dl_rq); | |
1412 | ||
1413 | /* | |
1414 | * Since we may have removed our earliest (and/or next earliest) | |
1415 | * task we must recompute them. | |
1416 | */ | |
1417 | if (!dl_rq->dl_nr_running) { | |
1418 | dl_rq->earliest_dl.curr = 0; | |
1419 | dl_rq->earliest_dl.next = 0; | |
d8206bb3 | 1420 | cpudl_clear(&rq->rd->cpudl, rq->cpu); |
b13772f8 | 1421 | cpupri_set(&rq->rd->cpupri, rq->cpu, rq->rt.highest_prio.curr); |
1baca4ce | 1422 | } else { |
2161573e | 1423 | struct rb_node *leftmost = dl_rq->root.rb_leftmost; |
1baca4ce JL |
1424 | struct sched_dl_entity *entry; |
1425 | ||
1426 | entry = rb_entry(leftmost, struct sched_dl_entity, rb_node); | |
1427 | dl_rq->earliest_dl.curr = entry->deadline; | |
d8206bb3 | 1428 | cpudl_set(&rq->rd->cpudl, rq->cpu, entry->deadline); |
1baca4ce JL |
1429 | } |
1430 | } | |
1431 | ||
1432 | #else | |
1433 | ||
1434 | static inline void inc_dl_deadline(struct dl_rq *dl_rq, u64 deadline) {} | |
1435 | static inline void dec_dl_deadline(struct dl_rq *dl_rq, u64 deadline) {} | |
1436 | ||
1437 | #endif /* CONFIG_SMP */ | |
1438 | ||
1439 | static inline | |
1440 | void inc_dl_tasks(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq) | |
1441 | { | |
1442 | int prio = dl_task_of(dl_se)->prio; | |
1443 | u64 deadline = dl_se->deadline; | |
1444 | ||
1445 | WARN_ON(!dl_prio(prio)); | |
1446 | dl_rq->dl_nr_running++; | |
72465447 | 1447 | add_nr_running(rq_of_dl_rq(dl_rq), 1); |
1baca4ce JL |
1448 | |
1449 | inc_dl_deadline(dl_rq, deadline); | |
1450 | inc_dl_migration(dl_se, dl_rq); | |
1451 | } | |
1452 | ||
1453 | static inline | |
1454 | void dec_dl_tasks(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq) | |
1455 | { | |
1456 | int prio = dl_task_of(dl_se)->prio; | |
1457 | ||
1458 | WARN_ON(!dl_prio(prio)); | |
1459 | WARN_ON(!dl_rq->dl_nr_running); | |
1460 | dl_rq->dl_nr_running--; | |
72465447 | 1461 | sub_nr_running(rq_of_dl_rq(dl_rq), 1); |
1baca4ce JL |
1462 | |
1463 | dec_dl_deadline(dl_rq, dl_se->deadline); | |
1464 | dec_dl_migration(dl_se, dl_rq); | |
1465 | } | |
1466 | ||
8ecca394 PZ |
1467 | #define __node_2_dle(node) \ |
1468 | rb_entry((node), struct sched_dl_entity, rb_node) | |
1469 | ||
1470 | static inline bool __dl_less(struct rb_node *a, const struct rb_node *b) | |
1471 | { | |
1472 | return dl_time_before(__node_2_dle(a)->deadline, __node_2_dle(b)->deadline); | |
1473 | } | |
1474 | ||
aab03e05 DF |
1475 | static void __enqueue_dl_entity(struct sched_dl_entity *dl_se) |
1476 | { | |
1477 | struct dl_rq *dl_rq = dl_rq_of_se(dl_se); | |
aab03e05 DF |
1478 | |
1479 | BUG_ON(!RB_EMPTY_NODE(&dl_se->rb_node)); | |
1480 | ||
8ecca394 | 1481 | rb_add_cached(&dl_se->rb_node, &dl_rq->root, __dl_less); |
aab03e05 | 1482 | |
1baca4ce | 1483 | inc_dl_tasks(dl_se, dl_rq); |
aab03e05 DF |
1484 | } |
1485 | ||
1486 | static void __dequeue_dl_entity(struct sched_dl_entity *dl_se) | |
1487 | { | |
1488 | struct dl_rq *dl_rq = dl_rq_of_se(dl_se); | |
1489 | ||
1490 | if (RB_EMPTY_NODE(&dl_se->rb_node)) | |
1491 | return; | |
1492 | ||
2161573e | 1493 | rb_erase_cached(&dl_se->rb_node, &dl_rq->root); |
8ecca394 | 1494 | |
aab03e05 DF |
1495 | RB_CLEAR_NODE(&dl_se->rb_node); |
1496 | ||
1baca4ce | 1497 | dec_dl_tasks(dl_se, dl_rq); |
aab03e05 DF |
1498 | } |
1499 | ||
1500 | static void | |
2279f540 | 1501 | enqueue_dl_entity(struct sched_dl_entity *dl_se, int flags) |
aab03e05 DF |
1502 | { |
1503 | BUG_ON(on_dl_rq(dl_se)); | |
1504 | ||
1505 | /* | |
1506 | * If this is a wakeup or a new instance, the scheduling | |
1507 | * parameters of the task might need updating. Otherwise, | |
1508 | * we want a replenishment of its runtime. | |
1509 | */ | |
e36d8677 | 1510 | if (flags & ENQUEUE_WAKEUP) { |
8fd27231 | 1511 | task_contending(dl_se, flags); |
2279f540 | 1512 | update_dl_entity(dl_se); |
e36d8677 | 1513 | } else if (flags & ENQUEUE_REPLENISH) { |
2279f540 | 1514 | replenish_dl_entity(dl_se); |
295d6d5e LA |
1515 | } else if ((flags & ENQUEUE_RESTORE) && |
1516 | dl_time_before(dl_se->deadline, | |
1517 | rq_clock(rq_of_dl_rq(dl_rq_of_se(dl_se))))) { | |
1518 | setup_new_dl_entity(dl_se); | |
e36d8677 | 1519 | } |
aab03e05 DF |
1520 | |
1521 | __enqueue_dl_entity(dl_se); | |
1522 | } | |
1523 | ||
1524 | static void dequeue_dl_entity(struct sched_dl_entity *dl_se) | |
1525 | { | |
1526 | __dequeue_dl_entity(dl_se); | |
1527 | } | |
1528 | ||
1529 | static void enqueue_task_dl(struct rq *rq, struct task_struct *p, int flags) | |
1530 | { | |
2279f540 | 1531 | if (is_dl_boosted(&p->dl)) { |
feff2e65 DBO |
1532 | /* |
1533 | * Because of delays in the detection of the overrun of a | |
1534 | * thread's runtime, it might be the case that a thread | |
1535 | * goes to sleep in a rt mutex with negative runtime. As | |
1536 | * a consequence, the thread will be throttled. | |
1537 | * | |
1538 | * While waiting for the mutex, this thread can also be | |
1539 | * boosted via PI, resulting in a thread that is throttled | |
1540 | * and boosted at the same time. | |
1541 | * | |
1542 | * In this case, the boost overrides the throttle. | |
1543 | */ | |
1544 | if (p->dl.dl_throttled) { | |
1545 | /* | |
1546 | * The replenish timer needs to be canceled. No | |
1547 | * problem if it fires concurrently: boosted threads | |
1548 | * are ignored in dl_task_timer(). | |
1549 | */ | |
1550 | hrtimer_try_to_cancel(&p->dl.dl_timer); | |
1551 | p->dl.dl_throttled = 0; | |
1552 | } | |
64be6f1f JL |
1553 | } else if (!dl_prio(p->normal_prio)) { |
1554 | /* | |
46fcc4b0 LS |
1555 | * Special case in which we have a !SCHED_DEADLINE task that is going |
1556 | * to be deboosted, but exceeds its runtime while doing so. No point in | |
1557 | * replenishing it, as it's going to return back to its original | |
1558 | * scheduling class after this. If it has been throttled, we need to | |
1559 | * clear the flag, otherwise the task may wake up as throttled after | |
1560 | * being boosted again with no means to replenish the runtime and clear | |
1561 | * the throttle. | |
64be6f1f | 1562 | */ |
46fcc4b0 | 1563 | p->dl.dl_throttled = 0; |
2279f540 | 1564 | BUG_ON(!is_dl_boosted(&p->dl) || flags != ENQUEUE_REPLENISH); |
64be6f1f JL |
1565 | return; |
1566 | } | |
2d3d891d | 1567 | |
df8eac8c DBO |
1568 | /* |
1569 | * Check if a constrained deadline task was activated | |
1570 | * after the deadline but before the next period. | |
1571 | * If that is the case, the task will be throttled and | |
1572 | * the replenishment timer will be set to the next period. | |
1573 | */ | |
3effcb42 | 1574 | if (!p->dl.dl_throttled && !dl_is_implicit(&p->dl)) |
df8eac8c DBO |
1575 | dl_check_constrained_dl(&p->dl); |
1576 | ||
8fd27231 | 1577 | if (p->on_rq == TASK_ON_RQ_MIGRATING || flags & ENQUEUE_RESTORE) { |
794a56eb JL |
1578 | add_rq_bw(&p->dl, &rq->dl); |
1579 | add_running_bw(&p->dl, &rq->dl); | |
8fd27231 | 1580 | } |
e36d8677 | 1581 | |
aab03e05 | 1582 | /* |
e36d8677 | 1583 | * If p is throttled, we do not enqueue it. In fact, if it exhausted |
aab03e05 DF |
1584 | * its budget it needs a replenishment and, since it now is on |
1585 | * its rq, the bandwidth timer callback (which clearly has not | |
1586 | * run yet) will take care of this. | |
e36d8677 LA |
1587 | * However, the active utilization does not depend on the fact |
1588 | * that the task is on the runqueue or not (but depends on the | |
1589 | * task's state - in GRUB parlance, "inactive" vs "active contending"). | |
1590 | * In other words, even if a task is throttled its utilization must | |
1591 | * be counted in the active utilization; hence, we need to call | |
1592 | * add_running_bw(). | |
aab03e05 | 1593 | */ |
e36d8677 | 1594 | if (p->dl.dl_throttled && !(flags & ENQUEUE_REPLENISH)) { |
209a0cbd | 1595 | if (flags & ENQUEUE_WAKEUP) |
8fd27231 | 1596 | task_contending(&p->dl, flags); |
209a0cbd | 1597 | |
aab03e05 | 1598 | return; |
e36d8677 | 1599 | } |
aab03e05 | 1600 | |
2279f540 | 1601 | enqueue_dl_entity(&p->dl, flags); |
1baca4ce | 1602 | |
4b53a341 | 1603 | if (!task_current(rq, p) && p->nr_cpus_allowed > 1) |
1baca4ce | 1604 | enqueue_pushable_dl_task(rq, p); |
aab03e05 DF |
1605 | } |
1606 | ||
1607 | static void __dequeue_task_dl(struct rq *rq, struct task_struct *p, int flags) | |
1608 | { | |
1609 | dequeue_dl_entity(&p->dl); | |
1baca4ce | 1610 | dequeue_pushable_dl_task(rq, p); |
aab03e05 DF |
1611 | } |
1612 | ||
1613 | static void dequeue_task_dl(struct rq *rq, struct task_struct *p, int flags) | |
1614 | { | |
1615 | update_curr_dl(rq); | |
1616 | __dequeue_task_dl(rq, p, flags); | |
e36d8677 | 1617 | |
8fd27231 | 1618 | if (p->on_rq == TASK_ON_RQ_MIGRATING || flags & DEQUEUE_SAVE) { |
794a56eb JL |
1619 | sub_running_bw(&p->dl, &rq->dl); |
1620 | sub_rq_bw(&p->dl, &rq->dl); | |
8fd27231 | 1621 | } |
e36d8677 LA |
1622 | |
1623 | /* | |
209a0cbd LA |
1624 | * This check allows to start the inactive timer (or to immediately |
1625 | * decrease the active utilization, if needed) in two cases: | |
e36d8677 LA |
1626 | * when the task blocks and when it is terminating |
1627 | * (p->state == TASK_DEAD). We can handle the two cases in the same | |
1628 | * way, because from GRUB's point of view the same thing is happening | |
1629 | * (the task moves from "active contending" to "active non contending" | |
1630 | * or "inactive") | |
1631 | */ | |
1632 | if (flags & DEQUEUE_SLEEP) | |
209a0cbd | 1633 | task_non_contending(p); |
aab03e05 DF |
1634 | } |
1635 | ||
1636 | /* | |
1637 | * Yield task semantic for -deadline tasks is: | |
1638 | * | |
1639 | * get off from the CPU until our next instance, with | |
1640 | * a new runtime. This is of little use now, since we | |
1641 | * don't have a bandwidth reclaiming mechanism. Anyway, | |
1642 | * bandwidth reclaiming is planned for the future, and | |
1643 | * yield_task_dl will indicate that some spare budget | |
1644 | * is available for other task instances to use it. | |
1645 | */ | |
1646 | static void yield_task_dl(struct rq *rq) | |
1647 | { | |
aab03e05 DF |
1648 | /* |
1649 | * We make the task go to sleep until its current deadline by | |
1650 | * forcing its runtime to zero. This way, update_curr_dl() stops | |
1651 | * it and the bandwidth timer will wake it up and will give it | |
5bfd126e | 1652 | * new scheduling parameters (thanks to dl_yielded=1). |
aab03e05 | 1653 | */ |
48be3a67 PZ |
1654 | rq->curr->dl.dl_yielded = 1; |
1655 | ||
6f1607f1 | 1656 | update_rq_clock(rq); |
aab03e05 | 1657 | update_curr_dl(rq); |
44fb085b WL |
1658 | /* |
1659 | * Tell update_rq_clock() that we've just updated, | |
1660 | * so we don't do microscopic update in schedule() | |
1661 | * and double the fastpath cost. | |
1662 | */ | |
adcc8da8 | 1663 | rq_clock_skip_update(rq); |
aab03e05 DF |
1664 | } |
1665 | ||
1baca4ce JL |
1666 | #ifdef CONFIG_SMP |
1667 | ||
1668 | static int find_later_rq(struct task_struct *task); | |
1baca4ce JL |
1669 | |
1670 | static int | |
3aef1551 | 1671 | select_task_rq_dl(struct task_struct *p, int cpu, int flags) |
1baca4ce JL |
1672 | { |
1673 | struct task_struct *curr; | |
b4118988 | 1674 | bool select_rq; |
1baca4ce JL |
1675 | struct rq *rq; |
1676 | ||
3aef1551 | 1677 | if (!(flags & WF_TTWU)) |
1baca4ce JL |
1678 | goto out; |
1679 | ||
1680 | rq = cpu_rq(cpu); | |
1681 | ||
1682 | rcu_read_lock(); | |
316c1608 | 1683 | curr = READ_ONCE(rq->curr); /* unlocked access */ |
1baca4ce JL |
1684 | |
1685 | /* | |
1686 | * If we are dealing with a -deadline task, we must | |
1687 | * decide where to wake it up. | |
1688 | * If it has a later deadline and the current task | |
1689 | * on this rq can't move (provided the waking task | |
1690 | * can!) we prefer to send it somewhere else. On the | |
1691 | * other hand, if it has a shorter deadline, we | |
1692 | * try to make it stay here, it might be important. | |
1693 | */ | |
b4118988 LA |
1694 | select_rq = unlikely(dl_task(curr)) && |
1695 | (curr->nr_cpus_allowed < 2 || | |
1696 | !dl_entity_preempt(&p->dl, &curr->dl)) && | |
1697 | p->nr_cpus_allowed > 1; | |
1698 | ||
1699 | /* | |
1700 | * Take the capacity of the CPU into account to | |
1701 | * ensure it fits the requirement of the task. | |
1702 | */ | |
1703 | if (static_branch_unlikely(&sched_asym_cpucapacity)) | |
1704 | select_rq |= !dl_task_fits_capacity(p, cpu); | |
1705 | ||
1706 | if (select_rq) { | |
1baca4ce JL |
1707 | int target = find_later_rq(p); |
1708 | ||
9d514262 | 1709 | if (target != -1 && |
5aa50507 LA |
1710 | (dl_time_before(p->dl.deadline, |
1711 | cpu_rq(target)->dl.earliest_dl.curr) || | |
1712 | (cpu_rq(target)->dl.dl_nr_running == 0))) | |
1baca4ce JL |
1713 | cpu = target; |
1714 | } | |
1715 | rcu_read_unlock(); | |
1716 | ||
1717 | out: | |
1718 | return cpu; | |
1719 | } | |
1720 | ||
1327237a | 1721 | static void migrate_task_rq_dl(struct task_struct *p, int new_cpu __maybe_unused) |
209a0cbd LA |
1722 | { |
1723 | struct rq *rq; | |
1724 | ||
2f064a59 | 1725 | if (READ_ONCE(p->__state) != TASK_WAKING) |
209a0cbd LA |
1726 | return; |
1727 | ||
1728 | rq = task_rq(p); | |
1729 | /* | |
1730 | * Since p->state == TASK_WAKING, set_task_cpu() has been called | |
1731 | * from try_to_wake_up(). Hence, p->pi_lock is locked, but | |
1732 | * rq->lock is not... So, lock it | |
1733 | */ | |
5cb9eaa3 | 1734 | raw_spin_rq_lock(rq); |
8fd27231 | 1735 | if (p->dl.dl_non_contending) { |
794a56eb | 1736 | sub_running_bw(&p->dl, &rq->dl); |
8fd27231 LA |
1737 | p->dl.dl_non_contending = 0; |
1738 | /* | |
1739 | * If the timer handler is currently running and the | |
3b03706f | 1740 | * timer cannot be canceled, inactive_task_timer() |
8fd27231 LA |
1741 | * will see that dl_not_contending is not set, and |
1742 | * will not touch the rq's active utilization, | |
1743 | * so we are still safe. | |
1744 | */ | |
1745 | if (hrtimer_try_to_cancel(&p->dl.inactive_timer) == 1) | |
1746 | put_task_struct(p); | |
1747 | } | |
794a56eb | 1748 | sub_rq_bw(&p->dl, &rq->dl); |
5cb9eaa3 | 1749 | raw_spin_rq_unlock(rq); |
209a0cbd LA |
1750 | } |
1751 | ||
1baca4ce JL |
1752 | static void check_preempt_equal_dl(struct rq *rq, struct task_struct *p) |
1753 | { | |
1754 | /* | |
1755 | * Current can't be migrated, useless to reschedule, | |
1756 | * let's hope p can move out. | |
1757 | */ | |
4b53a341 | 1758 | if (rq->curr->nr_cpus_allowed == 1 || |
3261ed0b | 1759 | !cpudl_find(&rq->rd->cpudl, rq->curr, NULL)) |
1baca4ce JL |
1760 | return; |
1761 | ||
1762 | /* | |
1763 | * p is migratable, so let's not schedule it and | |
1764 | * see if it is pushed or pulled somewhere else. | |
1765 | */ | |
4b53a341 | 1766 | if (p->nr_cpus_allowed != 1 && |
3261ed0b | 1767 | cpudl_find(&rq->rd->cpudl, p, NULL)) |
1baca4ce JL |
1768 | return; |
1769 | ||
8875125e | 1770 | resched_curr(rq); |
1baca4ce JL |
1771 | } |
1772 | ||
6e2df058 PZ |
1773 | static int balance_dl(struct rq *rq, struct task_struct *p, struct rq_flags *rf) |
1774 | { | |
1775 | if (!on_dl_rq(&p->dl) && need_pull_dl_task(rq, p)) { | |
1776 | /* | |
1777 | * This is OK, because current is on_cpu, which avoids it being | |
1778 | * picked for load-balance and preemption/IRQs are still | |
1779 | * disabled avoiding further scheduler activity on it and we've | |
1780 | * not yet started the picking loop. | |
1781 | */ | |
1782 | rq_unpin_lock(rq, rf); | |
1783 | pull_dl_task(rq); | |
1784 | rq_repin_lock(rq, rf); | |
1785 | } | |
1786 | ||
1787 | return sched_stop_runnable(rq) || sched_dl_runnable(rq); | |
1788 | } | |
1baca4ce JL |
1789 | #endif /* CONFIG_SMP */ |
1790 | ||
aab03e05 DF |
1791 | /* |
1792 | * Only called when both the current and waking task are -deadline | |
1793 | * tasks. | |
1794 | */ | |
1795 | static void check_preempt_curr_dl(struct rq *rq, struct task_struct *p, | |
1796 | int flags) | |
1797 | { | |
1baca4ce | 1798 | if (dl_entity_preempt(&p->dl, &rq->curr->dl)) { |
8875125e | 1799 | resched_curr(rq); |
1baca4ce JL |
1800 | return; |
1801 | } | |
1802 | ||
1803 | #ifdef CONFIG_SMP | |
1804 | /* | |
1805 | * In the unlikely case current and p have the same deadline | |
1806 | * let us try to decide what's the best thing to do... | |
1807 | */ | |
332ac17e DF |
1808 | if ((p->dl.deadline == rq->curr->dl.deadline) && |
1809 | !test_tsk_need_resched(rq->curr)) | |
1baca4ce JL |
1810 | check_preempt_equal_dl(rq, p); |
1811 | #endif /* CONFIG_SMP */ | |
aab03e05 DF |
1812 | } |
1813 | ||
1814 | #ifdef CONFIG_SCHED_HRTICK | |
1815 | static void start_hrtick_dl(struct rq *rq, struct task_struct *p) | |
1816 | { | |
177ef2a6 | 1817 | hrtick_start(rq, p->dl.runtime); |
aab03e05 | 1818 | } |
36ce9881 WL |
1819 | #else /* !CONFIG_SCHED_HRTICK */ |
1820 | static void start_hrtick_dl(struct rq *rq, struct task_struct *p) | |
1821 | { | |
1822 | } | |
aab03e05 DF |
1823 | #endif |
1824 | ||
a0e813f2 | 1825 | static void set_next_task_dl(struct rq *rq, struct task_struct *p, bool first) |
ff1cdc94 MS |
1826 | { |
1827 | p->se.exec_start = rq_clock_task(rq); | |
1828 | ||
1829 | /* You can't push away the running task */ | |
1830 | dequeue_pushable_dl_task(rq, p); | |
f95d4eae | 1831 | |
a0e813f2 PZ |
1832 | if (!first) |
1833 | return; | |
1834 | ||
e0ee463c | 1835 | if (hrtick_enabled_dl(rq)) |
f95d4eae PZ |
1836 | start_hrtick_dl(rq, p); |
1837 | ||
1838 | if (rq->curr->sched_class != &dl_sched_class) | |
1839 | update_dl_rq_load_avg(rq_clock_pelt(rq), rq, 0); | |
1840 | ||
1841 | deadline_queue_push_tasks(rq); | |
ff1cdc94 MS |
1842 | } |
1843 | ||
aab03e05 DF |
1844 | static struct sched_dl_entity *pick_next_dl_entity(struct rq *rq, |
1845 | struct dl_rq *dl_rq) | |
1846 | { | |
2161573e | 1847 | struct rb_node *left = rb_first_cached(&dl_rq->root); |
aab03e05 DF |
1848 | |
1849 | if (!left) | |
1850 | return NULL; | |
1851 | ||
1852 | return rb_entry(left, struct sched_dl_entity, rb_node); | |
1853 | } | |
1854 | ||
21f56ffe | 1855 | static struct task_struct *pick_task_dl(struct rq *rq) |
aab03e05 DF |
1856 | { |
1857 | struct sched_dl_entity *dl_se; | |
6e2df058 | 1858 | struct dl_rq *dl_rq = &rq->dl; |
aab03e05 | 1859 | struct task_struct *p; |
aab03e05 | 1860 | |
6e2df058 | 1861 | if (!sched_dl_runnable(rq)) |
aab03e05 DF |
1862 | return NULL; |
1863 | ||
1864 | dl_se = pick_next_dl_entity(rq, dl_rq); | |
1865 | BUG_ON(!dl_se); | |
aab03e05 | 1866 | p = dl_task_of(dl_se); |
21f56ffe PZ |
1867 | |
1868 | return p; | |
1869 | } | |
1870 | ||
1871 | static struct task_struct *pick_next_task_dl(struct rq *rq) | |
1872 | { | |
1873 | struct task_struct *p; | |
1874 | ||
1875 | p = pick_task_dl(rq); | |
1876 | if (p) | |
1877 | set_next_task_dl(rq, p, true); | |
1878 | ||
aab03e05 DF |
1879 | return p; |
1880 | } | |
1881 | ||
6e2df058 | 1882 | static void put_prev_task_dl(struct rq *rq, struct task_struct *p) |
aab03e05 DF |
1883 | { |
1884 | update_curr_dl(rq); | |
1baca4ce | 1885 | |
23127296 | 1886 | update_dl_rq_load_avg(rq_clock_pelt(rq), rq, 1); |
4b53a341 | 1887 | if (on_dl_rq(&p->dl) && p->nr_cpus_allowed > 1) |
1baca4ce | 1888 | enqueue_pushable_dl_task(rq, p); |
aab03e05 DF |
1889 | } |
1890 | ||
d84b3131 FW |
1891 | /* |
1892 | * scheduler tick hitting a task of our scheduling class. | |
1893 | * | |
1894 | * NOTE: This function can be called remotely by the tick offload that | |
1895 | * goes along full dynticks. Therefore no local assumption can be made | |
1896 | * and everything must be accessed through the @rq and @curr passed in | |
1897 | * parameters. | |
1898 | */ | |
aab03e05 DF |
1899 | static void task_tick_dl(struct rq *rq, struct task_struct *p, int queued) |
1900 | { | |
1901 | update_curr_dl(rq); | |
1902 | ||
23127296 | 1903 | update_dl_rq_load_avg(rq_clock_pelt(rq), rq, 1); |
a7bebf48 WL |
1904 | /* |
1905 | * Even when we have runtime, update_curr_dl() might have resulted in us | |
1906 | * not being the leftmost task anymore. In that case NEED_RESCHED will | |
1907 | * be set and schedule() will start a new hrtick for the next task. | |
1908 | */ | |
e0ee463c | 1909 | if (hrtick_enabled_dl(rq) && queued && p->dl.runtime > 0 && |
a7bebf48 | 1910 | is_leftmost(p, &rq->dl)) |
aab03e05 | 1911 | start_hrtick_dl(rq, p); |
aab03e05 DF |
1912 | } |
1913 | ||
1914 | static void task_fork_dl(struct task_struct *p) | |
1915 | { | |
1916 | /* | |
1917 | * SCHED_DEADLINE tasks cannot fork and this is achieved through | |
1918 | * sched_fork() | |
1919 | */ | |
1920 | } | |
1921 | ||
1baca4ce JL |
1922 | #ifdef CONFIG_SMP |
1923 | ||
1924 | /* Only try algorithms three times */ | |
1925 | #define DL_MAX_TRIES 3 | |
1926 | ||
1927 | static int pick_dl_task(struct rq *rq, struct task_struct *p, int cpu) | |
1928 | { | |
1929 | if (!task_running(rq, p) && | |
95158a89 | 1930 | cpumask_test_cpu(cpu, &p->cpus_mask)) |
1baca4ce | 1931 | return 1; |
1baca4ce JL |
1932 | return 0; |
1933 | } | |
1934 | ||
8b5e770e WL |
1935 | /* |
1936 | * Return the earliest pushable rq's task, which is suitable to be executed | |
1937 | * on the CPU, NULL otherwise: | |
1938 | */ | |
1939 | static struct task_struct *pick_earliest_pushable_dl_task(struct rq *rq, int cpu) | |
1940 | { | |
2161573e | 1941 | struct rb_node *next_node = rq->dl.pushable_dl_tasks_root.rb_leftmost; |
8b5e770e WL |
1942 | struct task_struct *p = NULL; |
1943 | ||
1944 | if (!has_pushable_dl_tasks(rq)) | |
1945 | return NULL; | |
1946 | ||
1947 | next_node: | |
1948 | if (next_node) { | |
1949 | p = rb_entry(next_node, struct task_struct, pushable_dl_tasks); | |
1950 | ||
1951 | if (pick_dl_task(rq, p, cpu)) | |
1952 | return p; | |
1953 | ||
1954 | next_node = rb_next(next_node); | |
1955 | goto next_node; | |
1956 | } | |
1957 | ||
1958 | return NULL; | |
1959 | } | |
1960 | ||
1baca4ce JL |
1961 | static DEFINE_PER_CPU(cpumask_var_t, local_cpu_mask_dl); |
1962 | ||
1963 | static int find_later_rq(struct task_struct *task) | |
1964 | { | |
1965 | struct sched_domain *sd; | |
4ba29684 | 1966 | struct cpumask *later_mask = this_cpu_cpumask_var_ptr(local_cpu_mask_dl); |
1baca4ce | 1967 | int this_cpu = smp_processor_id(); |
b18c3ca1 | 1968 | int cpu = task_cpu(task); |
1baca4ce JL |
1969 | |
1970 | /* Make sure the mask is initialized first */ | |
1971 | if (unlikely(!later_mask)) | |
1972 | return -1; | |
1973 | ||
4b53a341 | 1974 | if (task->nr_cpus_allowed == 1) |
1baca4ce JL |
1975 | return -1; |
1976 | ||
91ec6778 JL |
1977 | /* |
1978 | * We have to consider system topology and task affinity | |
97fb7a0a | 1979 | * first, then we can look for a suitable CPU. |
91ec6778 | 1980 | */ |
3261ed0b | 1981 | if (!cpudl_find(&task_rq(task)->rd->cpudl, task, later_mask)) |
1baca4ce JL |
1982 | return -1; |
1983 | ||
1984 | /* | |
b18c3ca1 BP |
1985 | * If we are here, some targets have been found, including |
1986 | * the most suitable which is, among the runqueues where the | |
1987 | * current tasks have later deadlines than the task's one, the | |
1988 | * rq with the latest possible one. | |
1baca4ce JL |
1989 | * |
1990 | * Now we check how well this matches with task's | |
1991 | * affinity and system topology. | |
1992 | * | |
97fb7a0a | 1993 | * The last CPU where the task run is our first |
1baca4ce JL |
1994 | * guess, since it is most likely cache-hot there. |
1995 | */ | |
1996 | if (cpumask_test_cpu(cpu, later_mask)) | |
1997 | return cpu; | |
1998 | /* | |
1999 | * Check if this_cpu is to be skipped (i.e., it is | |
2000 | * not in the mask) or not. | |
2001 | */ | |
2002 | if (!cpumask_test_cpu(this_cpu, later_mask)) | |
2003 | this_cpu = -1; | |
2004 | ||
2005 | rcu_read_lock(); | |
2006 | for_each_domain(cpu, sd) { | |
2007 | if (sd->flags & SD_WAKE_AFFINE) { | |
b18c3ca1 | 2008 | int best_cpu; |
1baca4ce JL |
2009 | |
2010 | /* | |
2011 | * If possible, preempting this_cpu is | |
2012 | * cheaper than migrating. | |
2013 | */ | |
2014 | if (this_cpu != -1 && | |
2015 | cpumask_test_cpu(this_cpu, sched_domain_span(sd))) { | |
2016 | rcu_read_unlock(); | |
2017 | return this_cpu; | |
2018 | } | |
2019 | ||
14e292f8 PZ |
2020 | best_cpu = cpumask_any_and_distribute(later_mask, |
2021 | sched_domain_span(sd)); | |
1baca4ce | 2022 | /* |
97fb7a0a | 2023 | * Last chance: if a CPU being in both later_mask |
b18c3ca1 | 2024 | * and current sd span is valid, that becomes our |
97fb7a0a | 2025 | * choice. Of course, the latest possible CPU is |
b18c3ca1 | 2026 | * already under consideration through later_mask. |
1baca4ce | 2027 | */ |
b18c3ca1 | 2028 | if (best_cpu < nr_cpu_ids) { |
1baca4ce JL |
2029 | rcu_read_unlock(); |
2030 | return best_cpu; | |
2031 | } | |
2032 | } | |
2033 | } | |
2034 | rcu_read_unlock(); | |
2035 | ||
2036 | /* | |
2037 | * At this point, all our guesses failed, we just return | |
2038 | * 'something', and let the caller sort the things out. | |
2039 | */ | |
2040 | if (this_cpu != -1) | |
2041 | return this_cpu; | |
2042 | ||
14e292f8 | 2043 | cpu = cpumask_any_distribute(later_mask); |
1baca4ce JL |
2044 | if (cpu < nr_cpu_ids) |
2045 | return cpu; | |
2046 | ||
2047 | return -1; | |
2048 | } | |
2049 | ||
2050 | /* Locks the rq it finds */ | |
2051 | static struct rq *find_lock_later_rq(struct task_struct *task, struct rq *rq) | |
2052 | { | |
2053 | struct rq *later_rq = NULL; | |
2054 | int tries; | |
2055 | int cpu; | |
2056 | ||
2057 | for (tries = 0; tries < DL_MAX_TRIES; tries++) { | |
2058 | cpu = find_later_rq(task); | |
2059 | ||
2060 | if ((cpu == -1) || (cpu == rq->cpu)) | |
2061 | break; | |
2062 | ||
2063 | later_rq = cpu_rq(cpu); | |
2064 | ||
5aa50507 LA |
2065 | if (later_rq->dl.dl_nr_running && |
2066 | !dl_time_before(task->dl.deadline, | |
9d514262 WL |
2067 | later_rq->dl.earliest_dl.curr)) { |
2068 | /* | |
2069 | * Target rq has tasks of equal or earlier deadline, | |
2070 | * retrying does not release any lock and is unlikely | |
2071 | * to yield a different result. | |
2072 | */ | |
2073 | later_rq = NULL; | |
2074 | break; | |
2075 | } | |
2076 | ||
1baca4ce JL |
2077 | /* Retry if something changed. */ |
2078 | if (double_lock_balance(rq, later_rq)) { | |
2079 | if (unlikely(task_rq(task) != rq || | |
95158a89 | 2080 | !cpumask_test_cpu(later_rq->cpu, &task->cpus_mask) || |
da0c1e65 | 2081 | task_running(rq, task) || |
13b5ab02 | 2082 | !dl_task(task) || |
da0c1e65 | 2083 | !task_on_rq_queued(task))) { |
1baca4ce JL |
2084 | double_unlock_balance(rq, later_rq); |
2085 | later_rq = NULL; | |
2086 | break; | |
2087 | } | |
2088 | } | |
2089 | ||
2090 | /* | |
2091 | * If the rq we found has no -deadline task, or | |
2092 | * its earliest one has a later deadline than our | |
2093 | * task, the rq is a good one. | |
2094 | */ | |
2095 | if (!later_rq->dl.dl_nr_running || | |
2096 | dl_time_before(task->dl.deadline, | |
2097 | later_rq->dl.earliest_dl.curr)) | |
2098 | break; | |
2099 | ||
2100 | /* Otherwise we try again. */ | |
2101 | double_unlock_balance(rq, later_rq); | |
2102 | later_rq = NULL; | |
2103 | } | |
2104 | ||
2105 | return later_rq; | |
2106 | } | |
2107 | ||
2108 | static struct task_struct *pick_next_pushable_dl_task(struct rq *rq) | |
2109 | { | |
2110 | struct task_struct *p; | |
2111 | ||
2112 | if (!has_pushable_dl_tasks(rq)) | |
2113 | return NULL; | |
2114 | ||
2161573e | 2115 | p = rb_entry(rq->dl.pushable_dl_tasks_root.rb_leftmost, |
1baca4ce JL |
2116 | struct task_struct, pushable_dl_tasks); |
2117 | ||
2118 | BUG_ON(rq->cpu != task_cpu(p)); | |
2119 | BUG_ON(task_current(rq, p)); | |
4b53a341 | 2120 | BUG_ON(p->nr_cpus_allowed <= 1); |
1baca4ce | 2121 | |
da0c1e65 | 2122 | BUG_ON(!task_on_rq_queued(p)); |
1baca4ce JL |
2123 | BUG_ON(!dl_task(p)); |
2124 | ||
2125 | return p; | |
2126 | } | |
2127 | ||
2128 | /* | |
2129 | * See if the non running -deadline tasks on this rq | |
2130 | * can be sent to some other CPU where they can preempt | |
2131 | * and start executing. | |
2132 | */ | |
2133 | static int push_dl_task(struct rq *rq) | |
2134 | { | |
2135 | struct task_struct *next_task; | |
2136 | struct rq *later_rq; | |
c51b8ab5 | 2137 | int ret = 0; |
1baca4ce JL |
2138 | |
2139 | if (!rq->dl.overloaded) | |
2140 | return 0; | |
2141 | ||
2142 | next_task = pick_next_pushable_dl_task(rq); | |
2143 | if (!next_task) | |
2144 | return 0; | |
2145 | ||
2146 | retry: | |
a7c81556 PZ |
2147 | if (is_migration_disabled(next_task)) |
2148 | return 0; | |
2149 | ||
9ebc6053 | 2150 | if (WARN_ON(next_task == rq->curr)) |
1baca4ce | 2151 | return 0; |
1baca4ce JL |
2152 | |
2153 | /* | |
2154 | * If next_task preempts rq->curr, and rq->curr | |
2155 | * can move away, it makes sense to just reschedule | |
2156 | * without going further in pushing next_task. | |
2157 | */ | |
2158 | if (dl_task(rq->curr) && | |
2159 | dl_time_before(next_task->dl.deadline, rq->curr->dl.deadline) && | |
4b53a341 | 2160 | rq->curr->nr_cpus_allowed > 1) { |
8875125e | 2161 | resched_curr(rq); |
1baca4ce JL |
2162 | return 0; |
2163 | } | |
2164 | ||
2165 | /* We might release rq lock */ | |
2166 | get_task_struct(next_task); | |
2167 | ||
2168 | /* Will lock the rq it'll find */ | |
2169 | later_rq = find_lock_later_rq(next_task, rq); | |
2170 | if (!later_rq) { | |
2171 | struct task_struct *task; | |
2172 | ||
2173 | /* | |
2174 | * We must check all this again, since | |
2175 | * find_lock_later_rq releases rq->lock and it is | |
2176 | * then possible that next_task has migrated. | |
2177 | */ | |
2178 | task = pick_next_pushable_dl_task(rq); | |
a776b968 | 2179 | if (task == next_task) { |
1baca4ce JL |
2180 | /* |
2181 | * The task is still there. We don't try | |
97fb7a0a | 2182 | * again, some other CPU will pull it when ready. |
1baca4ce | 2183 | */ |
1baca4ce JL |
2184 | goto out; |
2185 | } | |
2186 | ||
2187 | if (!task) | |
2188 | /* No more tasks */ | |
2189 | goto out; | |
2190 | ||
2191 | put_task_struct(next_task); | |
2192 | next_task = task; | |
2193 | goto retry; | |
2194 | } | |
2195 | ||
2196 | deactivate_task(rq, next_task, 0); | |
2197 | set_task_cpu(next_task, later_rq->cpu); | |
840d7196 DBO |
2198 | |
2199 | /* | |
2200 | * Update the later_rq clock here, because the clock is used | |
2201 | * by the cpufreq_update_util() inside __add_running_bw(). | |
2202 | */ | |
2203 | update_rq_clock(later_rq); | |
840d7196 | 2204 | activate_task(later_rq, next_task, ENQUEUE_NOCLOCK); |
c51b8ab5 | 2205 | ret = 1; |
1baca4ce | 2206 | |
8875125e | 2207 | resched_curr(later_rq); |
1baca4ce JL |
2208 | |
2209 | double_unlock_balance(rq, later_rq); | |
2210 | ||
2211 | out: | |
2212 | put_task_struct(next_task); | |
2213 | ||
c51b8ab5 | 2214 | return ret; |
1baca4ce JL |
2215 | } |
2216 | ||
2217 | static void push_dl_tasks(struct rq *rq) | |
2218 | { | |
4ffa08ed | 2219 | /* push_dl_task() will return true if it moved a -deadline task */ |
1baca4ce JL |
2220 | while (push_dl_task(rq)) |
2221 | ; | |
aab03e05 DF |
2222 | } |
2223 | ||
0ea60c20 | 2224 | static void pull_dl_task(struct rq *this_rq) |
1baca4ce | 2225 | { |
0ea60c20 | 2226 | int this_cpu = this_rq->cpu, cpu; |
a7c81556 | 2227 | struct task_struct *p, *push_task; |
0ea60c20 | 2228 | bool resched = false; |
1baca4ce JL |
2229 | struct rq *src_rq; |
2230 | u64 dmin = LONG_MAX; | |
2231 | ||
2232 | if (likely(!dl_overloaded(this_rq))) | |
0ea60c20 | 2233 | return; |
1baca4ce JL |
2234 | |
2235 | /* | |
2236 | * Match the barrier from dl_set_overloaded; this guarantees that if we | |
2237 | * see overloaded we must also see the dlo_mask bit. | |
2238 | */ | |
2239 | smp_rmb(); | |
2240 | ||
2241 | for_each_cpu(cpu, this_rq->rd->dlo_mask) { | |
2242 | if (this_cpu == cpu) | |
2243 | continue; | |
2244 | ||
2245 | src_rq = cpu_rq(cpu); | |
2246 | ||
2247 | /* | |
2248 | * It looks racy, abd it is! However, as in sched_rt.c, | |
2249 | * we are fine with this. | |
2250 | */ | |
2251 | if (this_rq->dl.dl_nr_running && | |
2252 | dl_time_before(this_rq->dl.earliest_dl.curr, | |
2253 | src_rq->dl.earliest_dl.next)) | |
2254 | continue; | |
2255 | ||
2256 | /* Might drop this_rq->lock */ | |
a7c81556 | 2257 | push_task = NULL; |
1baca4ce JL |
2258 | double_lock_balance(this_rq, src_rq); |
2259 | ||
2260 | /* | |
2261 | * If there are no more pullable tasks on the | |
2262 | * rq, we're done with it. | |
2263 | */ | |
2264 | if (src_rq->dl.dl_nr_running <= 1) | |
2265 | goto skip; | |
2266 | ||
8b5e770e | 2267 | p = pick_earliest_pushable_dl_task(src_rq, this_cpu); |
1baca4ce JL |
2268 | |
2269 | /* | |
2270 | * We found a task to be pulled if: | |
2271 | * - it preempts our current (if there's one), | |
2272 | * - it will preempt the last one we pulled (if any). | |
2273 | */ | |
2274 | if (p && dl_time_before(p->dl.deadline, dmin) && | |
2275 | (!this_rq->dl.dl_nr_running || | |
2276 | dl_time_before(p->dl.deadline, | |
2277 | this_rq->dl.earliest_dl.curr))) { | |
2278 | WARN_ON(p == src_rq->curr); | |
da0c1e65 | 2279 | WARN_ON(!task_on_rq_queued(p)); |
1baca4ce JL |
2280 | |
2281 | /* | |
2282 | * Then we pull iff p has actually an earlier | |
2283 | * deadline than the current task of its runqueue. | |
2284 | */ | |
2285 | if (dl_time_before(p->dl.deadline, | |
2286 | src_rq->curr->dl.deadline)) | |
2287 | goto skip; | |
2288 | ||
a7c81556 PZ |
2289 | if (is_migration_disabled(p)) { |
2290 | push_task = get_push_task(src_rq); | |
2291 | } else { | |
2292 | deactivate_task(src_rq, p, 0); | |
2293 | set_task_cpu(p, this_cpu); | |
2294 | activate_task(this_rq, p, 0); | |
2295 | dmin = p->dl.deadline; | |
2296 | resched = true; | |
2297 | } | |
1baca4ce JL |
2298 | |
2299 | /* Is there any other task even earlier? */ | |
2300 | } | |
2301 | skip: | |
2302 | double_unlock_balance(this_rq, src_rq); | |
a7c81556 PZ |
2303 | |
2304 | if (push_task) { | |
5cb9eaa3 | 2305 | raw_spin_rq_unlock(this_rq); |
a7c81556 PZ |
2306 | stop_one_cpu_nowait(src_rq->cpu, push_cpu_stop, |
2307 | push_task, &src_rq->push_work); | |
5cb9eaa3 | 2308 | raw_spin_rq_lock(this_rq); |
a7c81556 | 2309 | } |
1baca4ce JL |
2310 | } |
2311 | ||
0ea60c20 PZ |
2312 | if (resched) |
2313 | resched_curr(this_rq); | |
1baca4ce JL |
2314 | } |
2315 | ||
2316 | /* | |
2317 | * Since the task is not running and a reschedule is not going to happen | |
2318 | * anytime soon on its runqueue, we try pushing it away now. | |
2319 | */ | |
2320 | static void task_woken_dl(struct rq *rq, struct task_struct *p) | |
2321 | { | |
2322 | if (!task_running(rq, p) && | |
2323 | !test_tsk_need_resched(rq->curr) && | |
4b53a341 | 2324 | p->nr_cpus_allowed > 1 && |
1baca4ce | 2325 | dl_task(rq->curr) && |
4b53a341 | 2326 | (rq->curr->nr_cpus_allowed < 2 || |
6b0a563f | 2327 | !dl_entity_preempt(&p->dl, &rq->curr->dl))) { |
1baca4ce JL |
2328 | push_dl_tasks(rq); |
2329 | } | |
2330 | } | |
2331 | ||
2332 | static void set_cpus_allowed_dl(struct task_struct *p, | |
9cfc3e18 PZ |
2333 | const struct cpumask *new_mask, |
2334 | u32 flags) | |
1baca4ce | 2335 | { |
7f51412a | 2336 | struct root_domain *src_rd; |
6c37067e | 2337 | struct rq *rq; |
1baca4ce JL |
2338 | |
2339 | BUG_ON(!dl_task(p)); | |
2340 | ||
7f51412a JL |
2341 | rq = task_rq(p); |
2342 | src_rd = rq->rd; | |
2343 | /* | |
2344 | * Migrating a SCHED_DEADLINE task between exclusive | |
2345 | * cpusets (different root_domains) entails a bandwidth | |
2346 | * update. We already made space for us in the destination | |
2347 | * domain (see cpuset_can_attach()). | |
2348 | */ | |
2349 | if (!cpumask_intersects(src_rd->span, new_mask)) { | |
2350 | struct dl_bw *src_dl_b; | |
2351 | ||
2352 | src_dl_b = dl_bw_of(cpu_of(rq)); | |
2353 | /* | |
2354 | * We now free resources of the root_domain we are migrating | |
2355 | * off. In the worst case, sched_setattr() may temporary fail | |
2356 | * until we complete the update. | |
2357 | */ | |
2358 | raw_spin_lock(&src_dl_b->lock); | |
8c0944ce | 2359 | __dl_sub(src_dl_b, p->dl.dl_bw, dl_bw_cpus(task_cpu(p))); |
7f51412a JL |
2360 | raw_spin_unlock(&src_dl_b->lock); |
2361 | } | |
2362 | ||
9cfc3e18 | 2363 | set_cpus_allowed_common(p, new_mask, flags); |
1baca4ce JL |
2364 | } |
2365 | ||
2366 | /* Assumes rq->lock is held */ | |
2367 | static void rq_online_dl(struct rq *rq) | |
2368 | { | |
2369 | if (rq->dl.overloaded) | |
2370 | dl_set_overload(rq); | |
6bfd6d72 | 2371 | |
16b26943 | 2372 | cpudl_set_freecpu(&rq->rd->cpudl, rq->cpu); |
6bfd6d72 | 2373 | if (rq->dl.dl_nr_running > 0) |
d8206bb3 | 2374 | cpudl_set(&rq->rd->cpudl, rq->cpu, rq->dl.earliest_dl.curr); |
1baca4ce JL |
2375 | } |
2376 | ||
2377 | /* Assumes rq->lock is held */ | |
2378 | static void rq_offline_dl(struct rq *rq) | |
2379 | { | |
2380 | if (rq->dl.overloaded) | |
2381 | dl_clear_overload(rq); | |
6bfd6d72 | 2382 | |
d8206bb3 | 2383 | cpudl_clear(&rq->rd->cpudl, rq->cpu); |
16b26943 | 2384 | cpudl_clear_freecpu(&rq->rd->cpudl, rq->cpu); |
1baca4ce JL |
2385 | } |
2386 | ||
a6c0e746 | 2387 | void __init init_sched_dl_class(void) |
1baca4ce JL |
2388 | { |
2389 | unsigned int i; | |
2390 | ||
2391 | for_each_possible_cpu(i) | |
2392 | zalloc_cpumask_var_node(&per_cpu(local_cpu_mask_dl, i), | |
2393 | GFP_KERNEL, cpu_to_node(i)); | |
2394 | } | |
2395 | ||
f9a25f77 MP |
2396 | void dl_add_task_root_domain(struct task_struct *p) |
2397 | { | |
2398 | struct rq_flags rf; | |
2399 | struct rq *rq; | |
2400 | struct dl_bw *dl_b; | |
2401 | ||
de40f33e DE |
2402 | raw_spin_lock_irqsave(&p->pi_lock, rf.flags); |
2403 | if (!dl_task(p)) { | |
2404 | raw_spin_unlock_irqrestore(&p->pi_lock, rf.flags); | |
2405 | return; | |
2406 | } | |
2407 | ||
2408 | rq = __task_rq_lock(p, &rf); | |
f9a25f77 MP |
2409 | |
2410 | dl_b = &rq->rd->dl_bw; | |
2411 | raw_spin_lock(&dl_b->lock); | |
2412 | ||
2413 | __dl_add(dl_b, p->dl.dl_bw, cpumask_weight(rq->rd->span)); | |
2414 | ||
2415 | raw_spin_unlock(&dl_b->lock); | |
2416 | ||
f9a25f77 MP |
2417 | task_rq_unlock(rq, p, &rf); |
2418 | } | |
2419 | ||
2420 | void dl_clear_root_domain(struct root_domain *rd) | |
2421 | { | |
2422 | unsigned long flags; | |
2423 | ||
2424 | raw_spin_lock_irqsave(&rd->dl_bw.lock, flags); | |
2425 | rd->dl_bw.total_bw = 0; | |
2426 | raw_spin_unlock_irqrestore(&rd->dl_bw.lock, flags); | |
2427 | } | |
2428 | ||
1baca4ce JL |
2429 | #endif /* CONFIG_SMP */ |
2430 | ||
aab03e05 DF |
2431 | static void switched_from_dl(struct rq *rq, struct task_struct *p) |
2432 | { | |
a649f237 | 2433 | /* |
209a0cbd LA |
2434 | * task_non_contending() can start the "inactive timer" (if the 0-lag |
2435 | * time is in the future). If the task switches back to dl before | |
2436 | * the "inactive timer" fires, it can continue to consume its current | |
2437 | * runtime using its current deadline. If it stays outside of | |
2438 | * SCHED_DEADLINE until the 0-lag time passes, inactive_task_timer() | |
2439 | * will reset the task parameters. | |
a649f237 | 2440 | */ |
209a0cbd LA |
2441 | if (task_on_rq_queued(p) && p->dl.dl_runtime) |
2442 | task_non_contending(p); | |
2443 | ||
e117cb52 JL |
2444 | if (!task_on_rq_queued(p)) { |
2445 | /* | |
2446 | * Inactive timer is armed. However, p is leaving DEADLINE and | |
2447 | * might migrate away from this rq while continuing to run on | |
2448 | * some other class. We need to remove its contribution from | |
2449 | * this rq running_bw now, or sub_rq_bw (below) will complain. | |
2450 | */ | |
2451 | if (p->dl.dl_non_contending) | |
2452 | sub_running_bw(&p->dl, &rq->dl); | |
794a56eb | 2453 | sub_rq_bw(&p->dl, &rq->dl); |
e117cb52 | 2454 | } |
8fd27231 | 2455 | |
209a0cbd LA |
2456 | /* |
2457 | * We cannot use inactive_task_timer() to invoke sub_running_bw() | |
2458 | * at the 0-lag time, because the task could have been migrated | |
2459 | * while SCHED_OTHER in the meanwhile. | |
2460 | */ | |
2461 | if (p->dl.dl_non_contending) | |
2462 | p->dl.dl_non_contending = 0; | |
a5e7be3b | 2463 | |
1baca4ce JL |
2464 | /* |
2465 | * Since this might be the only -deadline task on the rq, | |
2466 | * this is the right place to try to pull some other one | |
97fb7a0a | 2467 | * from an overloaded CPU, if any. |
1baca4ce | 2468 | */ |
cd660911 WL |
2469 | if (!task_on_rq_queued(p) || rq->dl.dl_nr_running) |
2470 | return; | |
2471 | ||
02d8ec94 | 2472 | deadline_queue_pull_task(rq); |
aab03e05 DF |
2473 | } |
2474 | ||
1baca4ce JL |
2475 | /* |
2476 | * When switching to -deadline, we may overload the rq, then | |
2477 | * we try to push someone off, if possible. | |
2478 | */ | |
aab03e05 DF |
2479 | static void switched_to_dl(struct rq *rq, struct task_struct *p) |
2480 | { | |
209a0cbd LA |
2481 | if (hrtimer_try_to_cancel(&p->dl.inactive_timer) == 1) |
2482 | put_task_struct(p); | |
98b0a857 JL |
2483 | |
2484 | /* If p is not queued we will update its parameters at next wakeup. */ | |
8fd27231 | 2485 | if (!task_on_rq_queued(p)) { |
794a56eb | 2486 | add_rq_bw(&p->dl, &rq->dl); |
98b0a857 | 2487 | |
8fd27231 LA |
2488 | return; |
2489 | } | |
72f9f3fd | 2490 | |
98b0a857 | 2491 | if (rq->curr != p) { |
1baca4ce | 2492 | #ifdef CONFIG_SMP |
4b53a341 | 2493 | if (p->nr_cpus_allowed > 1 && rq->dl.overloaded) |
02d8ec94 | 2494 | deadline_queue_push_tasks(rq); |
619bd4a7 | 2495 | #endif |
9916e214 PZ |
2496 | if (dl_task(rq->curr)) |
2497 | check_preempt_curr_dl(rq, p, 0); | |
2498 | else | |
2499 | resched_curr(rq); | |
d7d60709 VD |
2500 | } else { |
2501 | update_dl_rq_load_avg(rq_clock_pelt(rq), rq, 0); | |
aab03e05 DF |
2502 | } |
2503 | } | |
2504 | ||
1baca4ce JL |
2505 | /* |
2506 | * If the scheduling parameters of a -deadline task changed, | |
2507 | * a push or pull operation might be needed. | |
2508 | */ | |
aab03e05 DF |
2509 | static void prio_changed_dl(struct rq *rq, struct task_struct *p, |
2510 | int oldprio) | |
2511 | { | |
65bcf072 | 2512 | if (task_on_rq_queued(p) || task_current(rq, p)) { |
aab03e05 | 2513 | #ifdef CONFIG_SMP |
1baca4ce JL |
2514 | /* |
2515 | * This might be too much, but unfortunately | |
2516 | * we don't have the old deadline value, and | |
2517 | * we can't argue if the task is increasing | |
2518 | * or lowering its prio, so... | |
2519 | */ | |
2520 | if (!rq->dl.overloaded) | |
02d8ec94 | 2521 | deadline_queue_pull_task(rq); |
1baca4ce JL |
2522 | |
2523 | /* | |
2524 | * If we now have a earlier deadline task than p, | |
2525 | * then reschedule, provided p is still on this | |
2526 | * runqueue. | |
2527 | */ | |
9916e214 | 2528 | if (dl_time_before(rq->dl.earliest_dl.curr, p->dl.deadline)) |
8875125e | 2529 | resched_curr(rq); |
1baca4ce JL |
2530 | #else |
2531 | /* | |
2532 | * Again, we don't know if p has a earlier | |
2533 | * or later deadline, so let's blindly set a | |
2534 | * (maybe not needed) rescheduling point. | |
2535 | */ | |
8875125e | 2536 | resched_curr(rq); |
1baca4ce | 2537 | #endif /* CONFIG_SMP */ |
801ccdbf | 2538 | } |
aab03e05 | 2539 | } |
aab03e05 | 2540 | |
43c31ac0 PZ |
2541 | DEFINE_SCHED_CLASS(dl) = { |
2542 | ||
aab03e05 DF |
2543 | .enqueue_task = enqueue_task_dl, |
2544 | .dequeue_task = dequeue_task_dl, | |
2545 | .yield_task = yield_task_dl, | |
2546 | ||
2547 | .check_preempt_curr = check_preempt_curr_dl, | |
2548 | ||
2549 | .pick_next_task = pick_next_task_dl, | |
2550 | .put_prev_task = put_prev_task_dl, | |
03b7fad1 | 2551 | .set_next_task = set_next_task_dl, |
aab03e05 DF |
2552 | |
2553 | #ifdef CONFIG_SMP | |
6e2df058 | 2554 | .balance = balance_dl, |
21f56ffe | 2555 | .pick_task = pick_task_dl, |
aab03e05 | 2556 | .select_task_rq = select_task_rq_dl, |
209a0cbd | 2557 | .migrate_task_rq = migrate_task_rq_dl, |
1baca4ce JL |
2558 | .set_cpus_allowed = set_cpus_allowed_dl, |
2559 | .rq_online = rq_online_dl, | |
2560 | .rq_offline = rq_offline_dl, | |
1baca4ce | 2561 | .task_woken = task_woken_dl, |
a7c81556 | 2562 | .find_lock_rq = find_lock_later_rq, |
aab03e05 DF |
2563 | #endif |
2564 | ||
aab03e05 DF |
2565 | .task_tick = task_tick_dl, |
2566 | .task_fork = task_fork_dl, | |
aab03e05 DF |
2567 | |
2568 | .prio_changed = prio_changed_dl, | |
2569 | .switched_from = switched_from_dl, | |
2570 | .switched_to = switched_to_dl, | |
6e998916 SG |
2571 | |
2572 | .update_curr = update_curr_dl, | |
aab03e05 | 2573 | }; |
acb32132 | 2574 | |
26762423 PL |
2575 | /* Used for dl_bw check and update, used under sched_rt_handler()::mutex */ |
2576 | static u64 dl_generation; | |
2577 | ||
06a76fe0 NP |
2578 | int sched_dl_global_validate(void) |
2579 | { | |
2580 | u64 runtime = global_rt_runtime(); | |
2581 | u64 period = global_rt_period(); | |
2582 | u64 new_bw = to_ratio(period, runtime); | |
26762423 | 2583 | u64 gen = ++dl_generation; |
06a76fe0 | 2584 | struct dl_bw *dl_b; |
a57415f5 | 2585 | int cpu, cpus, ret = 0; |
06a76fe0 NP |
2586 | unsigned long flags; |
2587 | ||
2588 | /* | |
2589 | * Here we want to check the bandwidth not being set to some | |
2590 | * value smaller than the currently allocated bandwidth in | |
2591 | * any of the root_domains. | |
06a76fe0 NP |
2592 | */ |
2593 | for_each_possible_cpu(cpu) { | |
2594 | rcu_read_lock_sched(); | |
26762423 PL |
2595 | |
2596 | if (dl_bw_visited(cpu, gen)) | |
2597 | goto next; | |
2598 | ||
06a76fe0 | 2599 | dl_b = dl_bw_of(cpu); |
a57415f5 | 2600 | cpus = dl_bw_cpus(cpu); |
06a76fe0 NP |
2601 | |
2602 | raw_spin_lock_irqsave(&dl_b->lock, flags); | |
a57415f5 | 2603 | if (new_bw * cpus < dl_b->total_bw) |
06a76fe0 NP |
2604 | ret = -EBUSY; |
2605 | raw_spin_unlock_irqrestore(&dl_b->lock, flags); | |
2606 | ||
26762423 | 2607 | next: |
06a76fe0 NP |
2608 | rcu_read_unlock_sched(); |
2609 | ||
2610 | if (ret) | |
2611 | break; | |
2612 | } | |
2613 | ||
2614 | return ret; | |
2615 | } | |
2616 | ||
ba4f7bc1 | 2617 | static void init_dl_rq_bw_ratio(struct dl_rq *dl_rq) |
06a76fe0 NP |
2618 | { |
2619 | if (global_rt_runtime() == RUNTIME_INF) { | |
2620 | dl_rq->bw_ratio = 1 << RATIO_SHIFT; | |
2621 | dl_rq->extra_bw = 1 << BW_SHIFT; | |
2622 | } else { | |
2623 | dl_rq->bw_ratio = to_ratio(global_rt_runtime(), | |
2624 | global_rt_period()) >> (BW_SHIFT - RATIO_SHIFT); | |
2625 | dl_rq->extra_bw = to_ratio(global_rt_period(), | |
2626 | global_rt_runtime()); | |
2627 | } | |
2628 | } | |
2629 | ||
2630 | void sched_dl_do_global(void) | |
2631 | { | |
2632 | u64 new_bw = -1; | |
26762423 | 2633 | u64 gen = ++dl_generation; |
06a76fe0 NP |
2634 | struct dl_bw *dl_b; |
2635 | int cpu; | |
2636 | unsigned long flags; | |
2637 | ||
2638 | def_dl_bandwidth.dl_period = global_rt_period(); | |
2639 | def_dl_bandwidth.dl_runtime = global_rt_runtime(); | |
2640 | ||
2641 | if (global_rt_runtime() != RUNTIME_INF) | |
2642 | new_bw = to_ratio(global_rt_period(), global_rt_runtime()); | |
2643 | ||
06a76fe0 NP |
2644 | for_each_possible_cpu(cpu) { |
2645 | rcu_read_lock_sched(); | |
26762423 PL |
2646 | |
2647 | if (dl_bw_visited(cpu, gen)) { | |
2648 | rcu_read_unlock_sched(); | |
2649 | continue; | |
2650 | } | |
2651 | ||
06a76fe0 NP |
2652 | dl_b = dl_bw_of(cpu); |
2653 | ||
2654 | raw_spin_lock_irqsave(&dl_b->lock, flags); | |
2655 | dl_b->bw = new_bw; | |
2656 | raw_spin_unlock_irqrestore(&dl_b->lock, flags); | |
2657 | ||
2658 | rcu_read_unlock_sched(); | |
2659 | init_dl_rq_bw_ratio(&cpu_rq(cpu)->dl); | |
2660 | } | |
2661 | } | |
2662 | ||
2663 | /* | |
2664 | * We must be sure that accepting a new task (or allowing changing the | |
2665 | * parameters of an existing one) is consistent with the bandwidth | |
2666 | * constraints. If yes, this function also accordingly updates the currently | |
2667 | * allocated bandwidth to reflect the new situation. | |
2668 | * | |
2669 | * This function is called while holding p's rq->lock. | |
2670 | */ | |
2671 | int sched_dl_overflow(struct task_struct *p, int policy, | |
2672 | const struct sched_attr *attr) | |
2673 | { | |
06a76fe0 NP |
2674 | u64 period = attr->sched_period ?: attr->sched_deadline; |
2675 | u64 runtime = attr->sched_runtime; | |
2676 | u64 new_bw = dl_policy(policy) ? to_ratio(period, runtime) : 0; | |
60ffd5ed LA |
2677 | int cpus, err = -1, cpu = task_cpu(p); |
2678 | struct dl_bw *dl_b = dl_bw_of(cpu); | |
2679 | unsigned long cap; | |
06a76fe0 | 2680 | |
794a56eb JL |
2681 | if (attr->sched_flags & SCHED_FLAG_SUGOV) |
2682 | return 0; | |
2683 | ||
06a76fe0 NP |
2684 | /* !deadline task may carry old deadline bandwidth */ |
2685 | if (new_bw == p->dl.dl_bw && task_has_dl_policy(p)) | |
2686 | return 0; | |
2687 | ||
2688 | /* | |
2689 | * Either if a task, enters, leave, or stays -deadline but changes | |
2690 | * its parameters, we may need to update accordingly the total | |
2691 | * allocated bandwidth of the container. | |
2692 | */ | |
2693 | raw_spin_lock(&dl_b->lock); | |
60ffd5ed LA |
2694 | cpus = dl_bw_cpus(cpu); |
2695 | cap = dl_bw_capacity(cpu); | |
2696 | ||
06a76fe0 | 2697 | if (dl_policy(policy) && !task_has_dl_policy(p) && |
60ffd5ed | 2698 | !__dl_overflow(dl_b, cap, 0, new_bw)) { |
06a76fe0 | 2699 | if (hrtimer_active(&p->dl.inactive_timer)) |
8c0944ce | 2700 | __dl_sub(dl_b, p->dl.dl_bw, cpus); |
06a76fe0 NP |
2701 | __dl_add(dl_b, new_bw, cpus); |
2702 | err = 0; | |
2703 | } else if (dl_policy(policy) && task_has_dl_policy(p) && | |
60ffd5ed | 2704 | !__dl_overflow(dl_b, cap, p->dl.dl_bw, new_bw)) { |
06a76fe0 NP |
2705 | /* |
2706 | * XXX this is slightly incorrect: when the task | |
2707 | * utilization decreases, we should delay the total | |
2708 | * utilization change until the task's 0-lag point. | |
2709 | * But this would require to set the task's "inactive | |
2710 | * timer" when the task is not inactive. | |
2711 | */ | |
8c0944ce | 2712 | __dl_sub(dl_b, p->dl.dl_bw, cpus); |
06a76fe0 NP |
2713 | __dl_add(dl_b, new_bw, cpus); |
2714 | dl_change_utilization(p, new_bw); | |
2715 | err = 0; | |
2716 | } else if (!dl_policy(policy) && task_has_dl_policy(p)) { | |
2717 | /* | |
2718 | * Do not decrease the total deadline utilization here, | |
2719 | * switched_from_dl() will take care to do it at the correct | |
2720 | * (0-lag) time. | |
2721 | */ | |
2722 | err = 0; | |
2723 | } | |
2724 | raw_spin_unlock(&dl_b->lock); | |
2725 | ||
2726 | return err; | |
2727 | } | |
2728 | ||
2729 | /* | |
2730 | * This function initializes the sched_dl_entity of a newly becoming | |
2731 | * SCHED_DEADLINE task. | |
2732 | * | |
2733 | * Only the static values are considered here, the actual runtime and the | |
2734 | * absolute deadline will be properly calculated when the task is enqueued | |
2735 | * for the first time with its new policy. | |
2736 | */ | |
2737 | void __setparam_dl(struct task_struct *p, const struct sched_attr *attr) | |
2738 | { | |
2739 | struct sched_dl_entity *dl_se = &p->dl; | |
2740 | ||
2741 | dl_se->dl_runtime = attr->sched_runtime; | |
2742 | dl_se->dl_deadline = attr->sched_deadline; | |
2743 | dl_se->dl_period = attr->sched_period ?: dl_se->dl_deadline; | |
2744 | dl_se->flags = attr->sched_flags; | |
2745 | dl_se->dl_bw = to_ratio(dl_se->dl_period, dl_se->dl_runtime); | |
2746 | dl_se->dl_density = to_ratio(dl_se->dl_deadline, dl_se->dl_runtime); | |
2747 | } | |
2748 | ||
2749 | void __getparam_dl(struct task_struct *p, struct sched_attr *attr) | |
2750 | { | |
2751 | struct sched_dl_entity *dl_se = &p->dl; | |
2752 | ||
2753 | attr->sched_priority = p->rt_priority; | |
2754 | attr->sched_runtime = dl_se->dl_runtime; | |
2755 | attr->sched_deadline = dl_se->dl_deadline; | |
2756 | attr->sched_period = dl_se->dl_period; | |
2757 | attr->sched_flags = dl_se->flags; | |
2758 | } | |
2759 | ||
b4098bfc PZ |
2760 | /* |
2761 | * Default limits for DL period; on the top end we guard against small util | |
3b03706f | 2762 | * tasks still getting ridiculously long effective runtimes, on the bottom end we |
b4098bfc PZ |
2763 | * guard against timer DoS. |
2764 | */ | |
2765 | unsigned int sysctl_sched_dl_period_max = 1 << 22; /* ~4 seconds */ | |
2766 | unsigned int sysctl_sched_dl_period_min = 100; /* 100 us */ | |
2767 | ||
06a76fe0 NP |
2768 | /* |
2769 | * This function validates the new parameters of a -deadline task. | |
2770 | * We ask for the deadline not being zero, and greater or equal | |
2771 | * than the runtime, as well as the period of being zero or | |
2772 | * greater than deadline. Furthermore, we have to be sure that | |
2773 | * user parameters are above the internal resolution of 1us (we | |
2774 | * check sched_runtime only since it is always the smaller one) and | |
2775 | * below 2^63 ns (we have to check both sched_deadline and | |
2776 | * sched_period, as the latter can be zero). | |
2777 | */ | |
2778 | bool __checkparam_dl(const struct sched_attr *attr) | |
2779 | { | |
b4098bfc PZ |
2780 | u64 period, max, min; |
2781 | ||
794a56eb JL |
2782 | /* special dl tasks don't actually use any parameter */ |
2783 | if (attr->sched_flags & SCHED_FLAG_SUGOV) | |
2784 | return true; | |
2785 | ||
06a76fe0 NP |
2786 | /* deadline != 0 */ |
2787 | if (attr->sched_deadline == 0) | |
2788 | return false; | |
2789 | ||
2790 | /* | |
2791 | * Since we truncate DL_SCALE bits, make sure we're at least | |
2792 | * that big. | |
2793 | */ | |
2794 | if (attr->sched_runtime < (1ULL << DL_SCALE)) | |
2795 | return false; | |
2796 | ||
2797 | /* | |
2798 | * Since we use the MSB for wrap-around and sign issues, make | |
2799 | * sure it's not set (mind that period can be equal to zero). | |
2800 | */ | |
2801 | if (attr->sched_deadline & (1ULL << 63) || | |
2802 | attr->sched_period & (1ULL << 63)) | |
2803 | return false; | |
2804 | ||
b4098bfc PZ |
2805 | period = attr->sched_period; |
2806 | if (!period) | |
2807 | period = attr->sched_deadline; | |
2808 | ||
06a76fe0 | 2809 | /* runtime <= deadline <= period (if period != 0) */ |
b4098bfc | 2810 | if (period < attr->sched_deadline || |
06a76fe0 NP |
2811 | attr->sched_deadline < attr->sched_runtime) |
2812 | return false; | |
2813 | ||
b4098bfc PZ |
2814 | max = (u64)READ_ONCE(sysctl_sched_dl_period_max) * NSEC_PER_USEC; |
2815 | min = (u64)READ_ONCE(sysctl_sched_dl_period_min) * NSEC_PER_USEC; | |
2816 | ||
2817 | if (period < min || period > max) | |
2818 | return false; | |
2819 | ||
06a76fe0 NP |
2820 | return true; |
2821 | } | |
2822 | ||
2823 | /* | |
2824 | * This function clears the sched_dl_entity static params. | |
2825 | */ | |
2826 | void __dl_clear_params(struct task_struct *p) | |
2827 | { | |
2828 | struct sched_dl_entity *dl_se = &p->dl; | |
2829 | ||
97fb7a0a IM |
2830 | dl_se->dl_runtime = 0; |
2831 | dl_se->dl_deadline = 0; | |
2832 | dl_se->dl_period = 0; | |
2833 | dl_se->flags = 0; | |
2834 | dl_se->dl_bw = 0; | |
2835 | dl_se->dl_density = 0; | |
06a76fe0 | 2836 | |
97fb7a0a IM |
2837 | dl_se->dl_throttled = 0; |
2838 | dl_se->dl_yielded = 0; | |
2839 | dl_se->dl_non_contending = 0; | |
2840 | dl_se->dl_overrun = 0; | |
2279f540 JL |
2841 | |
2842 | #ifdef CONFIG_RT_MUTEXES | |
2843 | dl_se->pi_se = dl_se; | |
2844 | #endif | |
06a76fe0 NP |
2845 | } |
2846 | ||
2847 | bool dl_param_changed(struct task_struct *p, const struct sched_attr *attr) | |
2848 | { | |
2849 | struct sched_dl_entity *dl_se = &p->dl; | |
2850 | ||
2851 | if (dl_se->dl_runtime != attr->sched_runtime || | |
2852 | dl_se->dl_deadline != attr->sched_deadline || | |
2853 | dl_se->dl_period != attr->sched_period || | |
2854 | dl_se->flags != attr->sched_flags) | |
2855 | return true; | |
2856 | ||
2857 | return false; | |
2858 | } | |
2859 | ||
2860 | #ifdef CONFIG_SMP | |
2861 | int dl_task_can_attach(struct task_struct *p, const struct cpumask *cs_cpus_allowed) | |
2862 | { | |
60ffd5ed | 2863 | unsigned long flags, cap; |
97fb7a0a | 2864 | unsigned int dest_cpu; |
06a76fe0 NP |
2865 | struct dl_bw *dl_b; |
2866 | bool overflow; | |
60ffd5ed | 2867 | int ret; |
06a76fe0 | 2868 | |
97fb7a0a IM |
2869 | dest_cpu = cpumask_any_and(cpu_active_mask, cs_cpus_allowed); |
2870 | ||
06a76fe0 NP |
2871 | rcu_read_lock_sched(); |
2872 | dl_b = dl_bw_of(dest_cpu); | |
2873 | raw_spin_lock_irqsave(&dl_b->lock, flags); | |
60ffd5ed LA |
2874 | cap = dl_bw_capacity(dest_cpu); |
2875 | overflow = __dl_overflow(dl_b, cap, 0, p->dl.dl_bw); | |
97fb7a0a | 2876 | if (overflow) { |
06a76fe0 | 2877 | ret = -EBUSY; |
97fb7a0a | 2878 | } else { |
06a76fe0 NP |
2879 | /* |
2880 | * We reserve space for this task in the destination | |
2881 | * root_domain, as we can't fail after this point. | |
2882 | * We will free resources in the source root_domain | |
2883 | * later on (see set_cpus_allowed_dl()). | |
2884 | */ | |
60ffd5ed LA |
2885 | int cpus = dl_bw_cpus(dest_cpu); |
2886 | ||
06a76fe0 NP |
2887 | __dl_add(dl_b, p->dl.dl_bw, cpus); |
2888 | ret = 0; | |
2889 | } | |
2890 | raw_spin_unlock_irqrestore(&dl_b->lock, flags); | |
2891 | rcu_read_unlock_sched(); | |
97fb7a0a | 2892 | |
06a76fe0 NP |
2893 | return ret; |
2894 | } | |
2895 | ||
2896 | int dl_cpuset_cpumask_can_shrink(const struct cpumask *cur, | |
2897 | const struct cpumask *trial) | |
2898 | { | |
2899 | int ret = 1, trial_cpus; | |
2900 | struct dl_bw *cur_dl_b; | |
2901 | unsigned long flags; | |
2902 | ||
2903 | rcu_read_lock_sched(); | |
2904 | cur_dl_b = dl_bw_of(cpumask_any(cur)); | |
2905 | trial_cpus = cpumask_weight(trial); | |
2906 | ||
2907 | raw_spin_lock_irqsave(&cur_dl_b->lock, flags); | |
2908 | if (cur_dl_b->bw != -1 && | |
2909 | cur_dl_b->bw * trial_cpus < cur_dl_b->total_bw) | |
2910 | ret = 0; | |
2911 | raw_spin_unlock_irqrestore(&cur_dl_b->lock, flags); | |
2912 | rcu_read_unlock_sched(); | |
97fb7a0a | 2913 | |
06a76fe0 NP |
2914 | return ret; |
2915 | } | |
2916 | ||
2917 | bool dl_cpu_busy(unsigned int cpu) | |
2918 | { | |
60ffd5ed | 2919 | unsigned long flags, cap; |
06a76fe0 NP |
2920 | struct dl_bw *dl_b; |
2921 | bool overflow; | |
06a76fe0 NP |
2922 | |
2923 | rcu_read_lock_sched(); | |
2924 | dl_b = dl_bw_of(cpu); | |
2925 | raw_spin_lock_irqsave(&dl_b->lock, flags); | |
60ffd5ed LA |
2926 | cap = dl_bw_capacity(cpu); |
2927 | overflow = __dl_overflow(dl_b, cap, 0, 0); | |
06a76fe0 NP |
2928 | raw_spin_unlock_irqrestore(&dl_b->lock, flags); |
2929 | rcu_read_unlock_sched(); | |
97fb7a0a | 2930 | |
06a76fe0 NP |
2931 | return overflow; |
2932 | } | |
2933 | #endif | |
2934 | ||
acb32132 | 2935 | #ifdef CONFIG_SCHED_DEBUG |
acb32132 WL |
2936 | void print_dl_stats(struct seq_file *m, int cpu) |
2937 | { | |
2938 | print_dl_rq(m, cpu, &cpu_rq(cpu)->dl); | |
2939 | } | |
2940 | #endif /* CONFIG_SCHED_DEBUG */ |