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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 | */ | |
aab03e05 | 18 | |
84227c12 ZN |
19 | /* |
20 | * Default limits for DL period; on the top end we guard against small util | |
21 | * tasks still getting ridiculously long effective runtimes, on the bottom end we | |
22 | * guard against timer DoS. | |
23 | */ | |
24 | static unsigned int sysctl_sched_dl_period_max = 1 << 22; /* ~4 seconds */ | |
25 | static unsigned int sysctl_sched_dl_period_min = 100; /* 100 us */ | |
26 | #ifdef CONFIG_SYSCTL | |
27 | static struct ctl_table sched_dl_sysctls[] = { | |
28 | { | |
29 | .procname = "sched_deadline_period_max_us", | |
30 | .data = &sysctl_sched_dl_period_max, | |
31 | .maxlen = sizeof(unsigned int), | |
32 | .mode = 0644, | |
2ed81e76 YD |
33 | .proc_handler = proc_douintvec_minmax, |
34 | .extra1 = (void *)&sysctl_sched_dl_period_min, | |
84227c12 ZN |
35 | }, |
36 | { | |
37 | .procname = "sched_deadline_period_min_us", | |
38 | .data = &sysctl_sched_dl_period_min, | |
39 | .maxlen = sizeof(unsigned int), | |
40 | .mode = 0644, | |
2ed81e76 YD |
41 | .proc_handler = proc_douintvec_minmax, |
42 | .extra2 = (void *)&sysctl_sched_dl_period_max, | |
84227c12 ZN |
43 | }, |
44 | {} | |
45 | }; | |
46 | ||
47 | static int __init sched_dl_sysctl_init(void) | |
48 | { | |
49 | register_sysctl_init("kernel", sched_dl_sysctls); | |
50 | return 0; | |
51 | } | |
52 | late_initcall(sched_dl_sysctl_init); | |
53 | #endif | |
54 | ||
aab03e05 DF |
55 | static inline struct task_struct *dl_task_of(struct sched_dl_entity *dl_se) |
56 | { | |
57 | return container_of(dl_se, struct task_struct, dl); | |
58 | } | |
59 | ||
60 | static inline struct rq *rq_of_dl_rq(struct dl_rq *dl_rq) | |
61 | { | |
62 | return container_of(dl_rq, struct rq, dl); | |
63 | } | |
64 | ||
65 | static inline struct dl_rq *dl_rq_of_se(struct sched_dl_entity *dl_se) | |
66 | { | |
67 | struct task_struct *p = dl_task_of(dl_se); | |
68 | struct rq *rq = task_rq(p); | |
69 | ||
70 | return &rq->dl; | |
71 | } | |
72 | ||
73 | static inline int on_dl_rq(struct sched_dl_entity *dl_se) | |
74 | { | |
75 | return !RB_EMPTY_NODE(&dl_se->rb_node); | |
76 | } | |
77 | ||
2279f540 JL |
78 | #ifdef CONFIG_RT_MUTEXES |
79 | static inline struct sched_dl_entity *pi_of(struct sched_dl_entity *dl_se) | |
80 | { | |
81 | return dl_se->pi_se; | |
82 | } | |
83 | ||
84 | static inline bool is_dl_boosted(struct sched_dl_entity *dl_se) | |
85 | { | |
86 | return pi_of(dl_se) != dl_se; | |
87 | } | |
88 | #else | |
89 | static inline struct sched_dl_entity *pi_of(struct sched_dl_entity *dl_se) | |
90 | { | |
91 | return dl_se; | |
92 | } | |
93 | ||
94 | static inline bool is_dl_boosted(struct sched_dl_entity *dl_se) | |
95 | { | |
96 | return false; | |
97 | } | |
98 | #endif | |
99 | ||
06a76fe0 NP |
100 | #ifdef CONFIG_SMP |
101 | static inline struct dl_bw *dl_bw_of(int i) | |
102 | { | |
103 | RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held(), | |
104 | "sched RCU must be held"); | |
105 | return &cpu_rq(i)->rd->dl_bw; | |
106 | } | |
107 | ||
108 | static inline int dl_bw_cpus(int i) | |
109 | { | |
110 | struct root_domain *rd = cpu_rq(i)->rd; | |
c81b8932 | 111 | int cpus; |
06a76fe0 NP |
112 | |
113 | RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held(), | |
114 | "sched RCU must be held"); | |
c81b8932 DE |
115 | |
116 | if (cpumask_subset(rd->span, cpu_active_mask)) | |
117 | return cpumask_weight(rd->span); | |
118 | ||
119 | cpus = 0; | |
120 | ||
06a76fe0 NP |
121 | for_each_cpu_and(i, rd->span, cpu_active_mask) |
122 | cpus++; | |
123 | ||
124 | return cpus; | |
125 | } | |
fc9dc698 | 126 | |
6092478b | 127 | static inline unsigned long __dl_bw_capacity(const struct cpumask *mask) |
fc9dc698 | 128 | { |
fc9dc698 | 129 | unsigned long cap = 0; |
6092478b | 130 | int i; |
fc9dc698 | 131 | |
6092478b | 132 | for_each_cpu_and(i, mask, cpu_active_mask) |
fc9dc698 DE |
133 | cap += capacity_orig_of(i); |
134 | ||
135 | return cap; | |
136 | } | |
137 | ||
138 | /* | |
139 | * XXX Fix: If 'rq->rd == def_root_domain' perform AC against capacity | |
140 | * of the CPU the task is running on rather rd's \Sum CPU capacity. | |
141 | */ | |
142 | static inline unsigned long dl_bw_capacity(int i) | |
143 | { | |
740cf8a7 | 144 | if (!sched_asym_cpucap_active() && |
fc9dc698 DE |
145 | capacity_orig_of(i) == SCHED_CAPACITY_SCALE) { |
146 | return dl_bw_cpus(i) << SCHED_CAPACITY_SHIFT; | |
147 | } else { | |
6092478b DE |
148 | RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held(), |
149 | "sched RCU must be held"); | |
150 | ||
151 | return __dl_bw_capacity(cpu_rq(i)->rd->span); | |
fc9dc698 DE |
152 | } |
153 | } | |
26762423 PL |
154 | |
155 | static inline bool dl_bw_visited(int cpu, u64 gen) | |
156 | { | |
157 | struct root_domain *rd = cpu_rq(cpu)->rd; | |
158 | ||
159 | if (rd->visit_gen == gen) | |
160 | return true; | |
161 | ||
162 | rd->visit_gen = gen; | |
163 | return false; | |
164 | } | |
f1304ecb DE |
165 | |
166 | static inline | |
167 | void __dl_update(struct dl_bw *dl_b, s64 bw) | |
168 | { | |
169 | struct root_domain *rd = container_of(dl_b, struct root_domain, dl_bw); | |
170 | int i; | |
171 | ||
172 | RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held(), | |
173 | "sched RCU must be held"); | |
174 | for_each_cpu_and(i, rd->span, cpu_active_mask) { | |
175 | struct rq *rq = cpu_rq(i); | |
176 | ||
177 | rq->dl.extra_bw += bw; | |
178 | } | |
179 | } | |
06a76fe0 NP |
180 | #else |
181 | static inline struct dl_bw *dl_bw_of(int i) | |
182 | { | |
183 | return &cpu_rq(i)->dl.dl_bw; | |
184 | } | |
185 | ||
186 | static inline int dl_bw_cpus(int i) | |
187 | { | |
188 | return 1; | |
189 | } | |
fc9dc698 DE |
190 | |
191 | static inline unsigned long dl_bw_capacity(int i) | |
192 | { | |
193 | return SCHED_CAPACITY_SCALE; | |
194 | } | |
26762423 PL |
195 | |
196 | static inline bool dl_bw_visited(int cpu, u64 gen) | |
197 | { | |
198 | return false; | |
199 | } | |
f1304ecb DE |
200 | |
201 | static inline | |
202 | void __dl_update(struct dl_bw *dl_b, s64 bw) | |
203 | { | |
204 | struct dl_rq *dl = container_of(dl_b, struct dl_rq, dl_bw); | |
205 | ||
206 | dl->extra_bw += bw; | |
207 | } | |
06a76fe0 NP |
208 | #endif |
209 | ||
f1304ecb DE |
210 | static inline |
211 | void __dl_sub(struct dl_bw *dl_b, u64 tsk_bw, int cpus) | |
212 | { | |
213 | dl_b->total_bw -= tsk_bw; | |
214 | __dl_update(dl_b, (s32)tsk_bw / cpus); | |
215 | } | |
216 | ||
217 | static inline | |
218 | void __dl_add(struct dl_bw *dl_b, u64 tsk_bw, int cpus) | |
219 | { | |
220 | dl_b->total_bw += tsk_bw; | |
221 | __dl_update(dl_b, -((s32)tsk_bw / cpus)); | |
222 | } | |
223 | ||
224 | static inline bool | |
225 | __dl_overflow(struct dl_bw *dl_b, unsigned long cap, u64 old_bw, u64 new_bw) | |
226 | { | |
227 | return dl_b->bw != -1 && | |
228 | cap_scale(dl_b->bw, cap) < dl_b->total_bw - old_bw + new_bw; | |
229 | } | |
230 | ||
e36d8677 | 231 | static inline |
794a56eb | 232 | void __add_running_bw(u64 dl_bw, struct dl_rq *dl_rq) |
e36d8677 LA |
233 | { |
234 | u64 old = dl_rq->running_bw; | |
235 | ||
5cb9eaa3 | 236 | lockdep_assert_rq_held(rq_of_dl_rq(dl_rq)); |
e36d8677 LA |
237 | dl_rq->running_bw += dl_bw; |
238 | SCHED_WARN_ON(dl_rq->running_bw < old); /* overflow */ | |
8fd27231 | 239 | SCHED_WARN_ON(dl_rq->running_bw > dl_rq->this_bw); |
e0367b12 | 240 | /* kick cpufreq (see the comment in kernel/sched/sched.h). */ |
4042d003 | 241 | cpufreq_update_util(rq_of_dl_rq(dl_rq), 0); |
e36d8677 LA |
242 | } |
243 | ||
244 | static inline | |
794a56eb | 245 | void __sub_running_bw(u64 dl_bw, struct dl_rq *dl_rq) |
e36d8677 LA |
246 | { |
247 | u64 old = dl_rq->running_bw; | |
248 | ||
5cb9eaa3 | 249 | lockdep_assert_rq_held(rq_of_dl_rq(dl_rq)); |
e36d8677 LA |
250 | dl_rq->running_bw -= dl_bw; |
251 | SCHED_WARN_ON(dl_rq->running_bw > old); /* underflow */ | |
252 | if (dl_rq->running_bw > old) | |
253 | dl_rq->running_bw = 0; | |
e0367b12 | 254 | /* kick cpufreq (see the comment in kernel/sched/sched.h). */ |
4042d003 | 255 | cpufreq_update_util(rq_of_dl_rq(dl_rq), 0); |
e36d8677 LA |
256 | } |
257 | ||
8fd27231 | 258 | static inline |
794a56eb | 259 | void __add_rq_bw(u64 dl_bw, struct dl_rq *dl_rq) |
8fd27231 LA |
260 | { |
261 | u64 old = dl_rq->this_bw; | |
262 | ||
5cb9eaa3 | 263 | lockdep_assert_rq_held(rq_of_dl_rq(dl_rq)); |
8fd27231 LA |
264 | dl_rq->this_bw += dl_bw; |
265 | SCHED_WARN_ON(dl_rq->this_bw < old); /* overflow */ | |
266 | } | |
267 | ||
268 | static inline | |
794a56eb | 269 | void __sub_rq_bw(u64 dl_bw, struct dl_rq *dl_rq) |
8fd27231 LA |
270 | { |
271 | u64 old = dl_rq->this_bw; | |
272 | ||
5cb9eaa3 | 273 | lockdep_assert_rq_held(rq_of_dl_rq(dl_rq)); |
8fd27231 LA |
274 | dl_rq->this_bw -= dl_bw; |
275 | SCHED_WARN_ON(dl_rq->this_bw > old); /* underflow */ | |
276 | if (dl_rq->this_bw > old) | |
277 | dl_rq->this_bw = 0; | |
278 | SCHED_WARN_ON(dl_rq->running_bw > dl_rq->this_bw); | |
279 | } | |
280 | ||
794a56eb JL |
281 | static inline |
282 | void add_rq_bw(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq) | |
283 | { | |
284 | if (!dl_entity_is_special(dl_se)) | |
285 | __add_rq_bw(dl_se->dl_bw, dl_rq); | |
286 | } | |
287 | ||
288 | static inline | |
289 | void sub_rq_bw(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq) | |
290 | { | |
291 | if (!dl_entity_is_special(dl_se)) | |
292 | __sub_rq_bw(dl_se->dl_bw, dl_rq); | |
293 | } | |
294 | ||
295 | static inline | |
296 | void add_running_bw(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq) | |
297 | { | |
298 | if (!dl_entity_is_special(dl_se)) | |
299 | __add_running_bw(dl_se->dl_bw, dl_rq); | |
300 | } | |
301 | ||
302 | static inline | |
303 | void sub_running_bw(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq) | |
304 | { | |
305 | if (!dl_entity_is_special(dl_se)) | |
306 | __sub_running_bw(dl_se->dl_bw, dl_rq); | |
307 | } | |
308 | ||
ba4f7bc1 | 309 | static void dl_change_utilization(struct task_struct *p, u64 new_bw) |
209a0cbd | 310 | { |
8fd27231 | 311 | struct rq *rq; |
209a0cbd | 312 | |
09348d75 | 313 | WARN_ON_ONCE(p->dl.flags & SCHED_FLAG_SUGOV); |
794a56eb | 314 | |
8fd27231 | 315 | if (task_on_rq_queued(p)) |
209a0cbd LA |
316 | return; |
317 | ||
8fd27231 LA |
318 | rq = task_rq(p); |
319 | if (p->dl.dl_non_contending) { | |
794a56eb | 320 | sub_running_bw(&p->dl, &rq->dl); |
8fd27231 LA |
321 | p->dl.dl_non_contending = 0; |
322 | /* | |
323 | * If the timer handler is currently running and the | |
3b03706f | 324 | * timer cannot be canceled, inactive_task_timer() |
8fd27231 LA |
325 | * will see that dl_not_contending is not set, and |
326 | * will not touch the rq's active utilization, | |
327 | * so we are still safe. | |
328 | */ | |
329 | if (hrtimer_try_to_cancel(&p->dl.inactive_timer) == 1) | |
330 | put_task_struct(p); | |
331 | } | |
794a56eb JL |
332 | __sub_rq_bw(p->dl.dl_bw, &rq->dl); |
333 | __add_rq_bw(new_bw, &rq->dl); | |
209a0cbd LA |
334 | } |
335 | ||
336 | /* | |
337 | * The utilization of a task cannot be immediately removed from | |
338 | * the rq active utilization (running_bw) when the task blocks. | |
339 | * Instead, we have to wait for the so called "0-lag time". | |
340 | * | |
341 | * If a task blocks before the "0-lag time", a timer (the inactive | |
342 | * timer) is armed, and running_bw is decreased when the timer | |
343 | * fires. | |
344 | * | |
345 | * If the task wakes up again before the inactive timer fires, | |
3b03706f | 346 | * the timer is canceled, whereas if the task wakes up after the |
209a0cbd LA |
347 | * inactive timer fired (and running_bw has been decreased) the |
348 | * task's utilization has to be added to running_bw again. | |
349 | * A flag in the deadline scheduling entity (dl_non_contending) | |
350 | * is used to avoid race conditions between the inactive timer handler | |
351 | * and task wakeups. | |
352 | * | |
353 | * The following diagram shows how running_bw is updated. A task is | |
354 | * "ACTIVE" when its utilization contributes to running_bw; an | |
355 | * "ACTIVE contending" task is in the TASK_RUNNING state, while an | |
356 | * "ACTIVE non contending" task is a blocked task for which the "0-lag time" | |
357 | * has not passed yet. An "INACTIVE" task is a task for which the "0-lag" | |
358 | * time already passed, which does not contribute to running_bw anymore. | |
359 | * +------------------+ | |
360 | * wakeup | ACTIVE | | |
361 | * +------------------>+ contending | | |
362 | * | add_running_bw | | | |
363 | * | +----+------+------+ | |
364 | * | | ^ | |
365 | * | dequeue | | | |
366 | * +--------+-------+ | | | |
367 | * | | t >= 0-lag | | wakeup | |
368 | * | INACTIVE |<---------------+ | | |
369 | * | | sub_running_bw | | | |
370 | * +--------+-------+ | | | |
371 | * ^ | | | |
372 | * | t < 0-lag | | | |
373 | * | | | | |
374 | * | V | | |
375 | * | +----+------+------+ | |
376 | * | sub_running_bw | ACTIVE | | |
377 | * +-------------------+ | | |
378 | * inactive timer | non contending | | |
379 | * fired +------------------+ | |
380 | * | |
381 | * The task_non_contending() function is invoked when a task | |
382 | * blocks, and checks if the 0-lag time already passed or | |
383 | * not (in the first case, it directly updates running_bw; | |
384 | * in the second case, it arms the inactive timer). | |
385 | * | |
386 | * The task_contending() function is invoked when a task wakes | |
387 | * up, and checks if the task is still in the "ACTIVE non contending" | |
388 | * state or not (in the second case, it updates running_bw). | |
389 | */ | |
390 | static void task_non_contending(struct task_struct *p) | |
391 | { | |
392 | struct sched_dl_entity *dl_se = &p->dl; | |
393 | struct hrtimer *timer = &dl_se->inactive_timer; | |
394 | struct dl_rq *dl_rq = dl_rq_of_se(dl_se); | |
395 | struct rq *rq = rq_of_dl_rq(dl_rq); | |
396 | s64 zerolag_time; | |
397 | ||
398 | /* | |
399 | * If this is a non-deadline task that has been boosted, | |
400 | * do nothing | |
401 | */ | |
402 | if (dl_se->dl_runtime == 0) | |
403 | return; | |
404 | ||
794a56eb JL |
405 | if (dl_entity_is_special(dl_se)) |
406 | return; | |
407 | ||
209a0cbd LA |
408 | WARN_ON(dl_se->dl_non_contending); |
409 | ||
410 | zerolag_time = dl_se->deadline - | |
411 | div64_long((dl_se->runtime * dl_se->dl_period), | |
412 | dl_se->dl_runtime); | |
413 | ||
414 | /* | |
415 | * Using relative times instead of the absolute "0-lag time" | |
416 | * allows to simplify the code | |
417 | */ | |
418 | zerolag_time -= rq_clock(rq); | |
419 | ||
420 | /* | |
421 | * If the "0-lag time" already passed, decrease the active | |
422 | * utilization now, instead of starting a timer | |
423 | */ | |
1b02cd6a | 424 | if ((zerolag_time < 0) || hrtimer_active(&dl_se->inactive_timer)) { |
209a0cbd | 425 | if (dl_task(p)) |
794a56eb | 426 | sub_running_bw(dl_se, dl_rq); |
2f064a59 | 427 | if (!dl_task(p) || READ_ONCE(p->__state) == TASK_DEAD) { |
387e3130 LA |
428 | struct dl_bw *dl_b = dl_bw_of(task_cpu(p)); |
429 | ||
2f064a59 | 430 | if (READ_ONCE(p->__state) == TASK_DEAD) |
794a56eb | 431 | sub_rq_bw(&p->dl, &rq->dl); |
387e3130 | 432 | raw_spin_lock(&dl_b->lock); |
8c0944ce | 433 | __dl_sub(dl_b, p->dl.dl_bw, dl_bw_cpus(task_cpu(p))); |
209a0cbd | 434 | __dl_clear_params(p); |
387e3130 LA |
435 | raw_spin_unlock(&dl_b->lock); |
436 | } | |
209a0cbd LA |
437 | |
438 | return; | |
439 | } | |
440 | ||
441 | dl_se->dl_non_contending = 1; | |
442 | get_task_struct(p); | |
850377a8 | 443 | hrtimer_start(timer, ns_to_ktime(zerolag_time), HRTIMER_MODE_REL_HARD); |
209a0cbd LA |
444 | } |
445 | ||
8fd27231 | 446 | static void task_contending(struct sched_dl_entity *dl_se, int flags) |
209a0cbd LA |
447 | { |
448 | struct dl_rq *dl_rq = dl_rq_of_se(dl_se); | |
449 | ||
450 | /* | |
451 | * If this is a non-deadline task that has been boosted, | |
452 | * do nothing | |
453 | */ | |
454 | if (dl_se->dl_runtime == 0) | |
455 | return; | |
456 | ||
8fd27231 | 457 | if (flags & ENQUEUE_MIGRATED) |
794a56eb | 458 | add_rq_bw(dl_se, dl_rq); |
8fd27231 | 459 | |
209a0cbd LA |
460 | if (dl_se->dl_non_contending) { |
461 | dl_se->dl_non_contending = 0; | |
462 | /* | |
463 | * If the timer handler is currently running and the | |
3b03706f | 464 | * timer cannot be canceled, inactive_task_timer() |
209a0cbd LA |
465 | * will see that dl_not_contending is not set, and |
466 | * will not touch the rq's active utilization, | |
467 | * so we are still safe. | |
468 | */ | |
469 | if (hrtimer_try_to_cancel(&dl_se->inactive_timer) == 1) | |
470 | put_task_struct(dl_task_of(dl_se)); | |
471 | } else { | |
472 | /* | |
473 | * Since "dl_non_contending" is not set, the | |
474 | * task's utilization has already been removed from | |
475 | * active utilization (either when the task blocked, | |
476 | * when the "inactive timer" fired). | |
477 | * So, add it back. | |
478 | */ | |
794a56eb | 479 | add_running_bw(dl_se, dl_rq); |
209a0cbd LA |
480 | } |
481 | } | |
482 | ||
aab03e05 DF |
483 | static inline int is_leftmost(struct task_struct *p, struct dl_rq *dl_rq) |
484 | { | |
485 | struct sched_dl_entity *dl_se = &p->dl; | |
486 | ||
f4478e7c | 487 | return rb_first_cached(&dl_rq->root) == &dl_se->rb_node; |
aab03e05 DF |
488 | } |
489 | ||
ba4f7bc1 YC |
490 | static void init_dl_rq_bw_ratio(struct dl_rq *dl_rq); |
491 | ||
332ac17e DF |
492 | void init_dl_bandwidth(struct dl_bandwidth *dl_b, u64 period, u64 runtime) |
493 | { | |
494 | raw_spin_lock_init(&dl_b->dl_runtime_lock); | |
495 | dl_b->dl_period = period; | |
496 | dl_b->dl_runtime = runtime; | |
497 | } | |
498 | ||
332ac17e DF |
499 | void init_dl_bw(struct dl_bw *dl_b) |
500 | { | |
501 | raw_spin_lock_init(&dl_b->lock); | |
1724813d | 502 | if (global_rt_runtime() == RUNTIME_INF) |
332ac17e DF |
503 | dl_b->bw = -1; |
504 | else | |
1724813d | 505 | dl_b->bw = to_ratio(global_rt_period(), global_rt_runtime()); |
332ac17e DF |
506 | dl_b->total_bw = 0; |
507 | } | |
508 | ||
07c54f7a | 509 | void init_dl_rq(struct dl_rq *dl_rq) |
aab03e05 | 510 | { |
2161573e | 511 | dl_rq->root = RB_ROOT_CACHED; |
1baca4ce JL |
512 | |
513 | #ifdef CONFIG_SMP | |
514 | /* zero means no -deadline tasks */ | |
515 | dl_rq->earliest_dl.curr = dl_rq->earliest_dl.next = 0; | |
516 | ||
517 | dl_rq->dl_nr_migratory = 0; | |
518 | dl_rq->overloaded = 0; | |
2161573e | 519 | dl_rq->pushable_dl_tasks_root = RB_ROOT_CACHED; |
332ac17e DF |
520 | #else |
521 | init_dl_bw(&dl_rq->dl_bw); | |
1baca4ce | 522 | #endif |
e36d8677 LA |
523 | |
524 | dl_rq->running_bw = 0; | |
8fd27231 | 525 | dl_rq->this_bw = 0; |
4da3abce | 526 | init_dl_rq_bw_ratio(dl_rq); |
1baca4ce JL |
527 | } |
528 | ||
529 | #ifdef CONFIG_SMP | |
530 | ||
531 | static inline int dl_overloaded(struct rq *rq) | |
532 | { | |
533 | return atomic_read(&rq->rd->dlo_count); | |
534 | } | |
535 | ||
536 | static inline void dl_set_overload(struct rq *rq) | |
537 | { | |
538 | if (!rq->online) | |
539 | return; | |
540 | ||
541 | cpumask_set_cpu(rq->cpu, rq->rd->dlo_mask); | |
542 | /* | |
543 | * Must be visible before the overload count is | |
544 | * set (as in sched_rt.c). | |
545 | * | |
546 | * Matched by the barrier in pull_dl_task(). | |
547 | */ | |
548 | smp_wmb(); | |
549 | atomic_inc(&rq->rd->dlo_count); | |
550 | } | |
551 | ||
552 | static inline void dl_clear_overload(struct rq *rq) | |
553 | { | |
554 | if (!rq->online) | |
555 | return; | |
556 | ||
557 | atomic_dec(&rq->rd->dlo_count); | |
558 | cpumask_clear_cpu(rq->cpu, rq->rd->dlo_mask); | |
559 | } | |
560 | ||
561 | static void update_dl_migration(struct dl_rq *dl_rq) | |
562 | { | |
995b9ea4 | 563 | if (dl_rq->dl_nr_migratory && dl_rq->dl_nr_running > 1) { |
1baca4ce JL |
564 | if (!dl_rq->overloaded) { |
565 | dl_set_overload(rq_of_dl_rq(dl_rq)); | |
566 | dl_rq->overloaded = 1; | |
567 | } | |
568 | } else if (dl_rq->overloaded) { | |
569 | dl_clear_overload(rq_of_dl_rq(dl_rq)); | |
570 | dl_rq->overloaded = 0; | |
571 | } | |
572 | } | |
573 | ||
574 | static void inc_dl_migration(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq) | |
575 | { | |
576 | struct task_struct *p = dl_task_of(dl_se); | |
1baca4ce | 577 | |
4b53a341 | 578 | if (p->nr_cpus_allowed > 1) |
1baca4ce JL |
579 | dl_rq->dl_nr_migratory++; |
580 | ||
581 | update_dl_migration(dl_rq); | |
582 | } | |
583 | ||
584 | static void dec_dl_migration(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq) | |
585 | { | |
586 | struct task_struct *p = dl_task_of(dl_se); | |
1baca4ce | 587 | |
4b53a341 | 588 | if (p->nr_cpus_allowed > 1) |
1baca4ce JL |
589 | dl_rq->dl_nr_migratory--; |
590 | ||
591 | update_dl_migration(dl_rq); | |
592 | } | |
593 | ||
8ecca394 PZ |
594 | #define __node_2_pdl(node) \ |
595 | rb_entry((node), struct task_struct, pushable_dl_tasks) | |
596 | ||
597 | static inline bool __pushable_less(struct rb_node *a, const struct rb_node *b) | |
598 | { | |
599 | return dl_entity_preempt(&__node_2_pdl(a)->dl, &__node_2_pdl(b)->dl); | |
600 | } | |
601 | ||
1baca4ce JL |
602 | /* |
603 | * The list of pushable -deadline task is not a plist, like in | |
604 | * sched_rt.c, it is an rb-tree with tasks ordered by deadline. | |
605 | */ | |
606 | static void enqueue_pushable_dl_task(struct rq *rq, struct task_struct *p) | |
607 | { | |
8ecca394 | 608 | struct rb_node *leftmost; |
1baca4ce | 609 | |
09348d75 | 610 | WARN_ON_ONCE(!RB_EMPTY_NODE(&p->pushable_dl_tasks)); |
1baca4ce | 611 | |
8ecca394 PZ |
612 | leftmost = rb_add_cached(&p->pushable_dl_tasks, |
613 | &rq->dl.pushable_dl_tasks_root, | |
614 | __pushable_less); | |
2161573e | 615 | if (leftmost) |
8ecca394 | 616 | rq->dl.earliest_dl.next = p->dl.deadline; |
aab03e05 DF |
617 | } |
618 | ||
1baca4ce JL |
619 | static void dequeue_pushable_dl_task(struct rq *rq, struct task_struct *p) |
620 | { | |
621 | struct dl_rq *dl_rq = &rq->dl; | |
8ecca394 PZ |
622 | struct rb_root_cached *root = &dl_rq->pushable_dl_tasks_root; |
623 | struct rb_node *leftmost; | |
1baca4ce JL |
624 | |
625 | if (RB_EMPTY_NODE(&p->pushable_dl_tasks)) | |
626 | return; | |
627 | ||
8ecca394 PZ |
628 | leftmost = rb_erase_cached(&p->pushable_dl_tasks, root); |
629 | if (leftmost) | |
630 | dl_rq->earliest_dl.next = __node_2_pdl(leftmost)->dl.deadline; | |
1baca4ce | 631 | |
1baca4ce JL |
632 | RB_CLEAR_NODE(&p->pushable_dl_tasks); |
633 | } | |
634 | ||
635 | static inline int has_pushable_dl_tasks(struct rq *rq) | |
636 | { | |
2161573e | 637 | return !RB_EMPTY_ROOT(&rq->dl.pushable_dl_tasks_root.rb_root); |
1baca4ce JL |
638 | } |
639 | ||
640 | static int push_dl_task(struct rq *rq); | |
641 | ||
dc877341 PZ |
642 | static inline bool need_pull_dl_task(struct rq *rq, struct task_struct *prev) |
643 | { | |
120455c5 | 644 | return rq->online && dl_task(prev); |
dc877341 PZ |
645 | } |
646 | ||
9916e214 PZ |
647 | static DEFINE_PER_CPU(struct callback_head, dl_push_head); |
648 | static DEFINE_PER_CPU(struct callback_head, dl_pull_head); | |
e3fca9e7 PZ |
649 | |
650 | static void push_dl_tasks(struct rq *); | |
9916e214 | 651 | static void pull_dl_task(struct rq *); |
e3fca9e7 | 652 | |
02d8ec94 | 653 | static inline void deadline_queue_push_tasks(struct rq *rq) |
dc877341 | 654 | { |
e3fca9e7 PZ |
655 | if (!has_pushable_dl_tasks(rq)) |
656 | return; | |
657 | ||
9916e214 PZ |
658 | queue_balance_callback(rq, &per_cpu(dl_push_head, rq->cpu), push_dl_tasks); |
659 | } | |
660 | ||
02d8ec94 | 661 | static inline void deadline_queue_pull_task(struct rq *rq) |
9916e214 PZ |
662 | { |
663 | queue_balance_callback(rq, &per_cpu(dl_pull_head, rq->cpu), pull_dl_task); | |
dc877341 PZ |
664 | } |
665 | ||
fa9c9d10 WL |
666 | static struct rq *find_lock_later_rq(struct task_struct *task, struct rq *rq); |
667 | ||
a649f237 | 668 | static struct rq *dl_task_offline_migration(struct rq *rq, struct task_struct *p) |
fa9c9d10 WL |
669 | { |
670 | struct rq *later_rq = NULL; | |
59d06cea | 671 | struct dl_bw *dl_b; |
fa9c9d10 WL |
672 | |
673 | later_rq = find_lock_later_rq(p, rq); | |
fa9c9d10 WL |
674 | if (!later_rq) { |
675 | int cpu; | |
676 | ||
677 | /* | |
678 | * If we cannot preempt any rq, fall back to pick any | |
97fb7a0a | 679 | * online CPU: |
fa9c9d10 | 680 | */ |
3bd37062 | 681 | cpu = cpumask_any_and(cpu_active_mask, p->cpus_ptr); |
fa9c9d10 WL |
682 | if (cpu >= nr_cpu_ids) { |
683 | /* | |
97fb7a0a | 684 | * Failed to find any suitable CPU. |
fa9c9d10 WL |
685 | * The task will never come back! |
686 | */ | |
09348d75 | 687 | WARN_ON_ONCE(dl_bandwidth_enabled()); |
fa9c9d10 WL |
688 | |
689 | /* | |
690 | * If admission control is disabled we | |
691 | * try a little harder to let the task | |
692 | * run. | |
693 | */ | |
694 | cpu = cpumask_any(cpu_active_mask); | |
695 | } | |
696 | later_rq = cpu_rq(cpu); | |
697 | double_lock_balance(rq, later_rq); | |
698 | } | |
699 | ||
59d06cea JL |
700 | if (p->dl.dl_non_contending || p->dl.dl_throttled) { |
701 | /* | |
702 | * Inactive timer is armed (or callback is running, but | |
703 | * waiting for us to release rq locks). In any case, when it | |
704 | * will fire (or continue), it will see running_bw of this | |
705 | * task migrated to later_rq (and correctly handle it). | |
706 | */ | |
707 | sub_running_bw(&p->dl, &rq->dl); | |
708 | sub_rq_bw(&p->dl, &rq->dl); | |
709 | ||
710 | add_rq_bw(&p->dl, &later_rq->dl); | |
711 | add_running_bw(&p->dl, &later_rq->dl); | |
712 | } else { | |
713 | sub_rq_bw(&p->dl, &rq->dl); | |
714 | add_rq_bw(&p->dl, &later_rq->dl); | |
715 | } | |
716 | ||
717 | /* | |
718 | * And we finally need to fixup root_domain(s) bandwidth accounting, | |
719 | * since p is still hanging out in the old (now moved to default) root | |
720 | * domain. | |
721 | */ | |
722 | dl_b = &rq->rd->dl_bw; | |
723 | raw_spin_lock(&dl_b->lock); | |
724 | __dl_sub(dl_b, p->dl.dl_bw, cpumask_weight(rq->rd->span)); | |
725 | raw_spin_unlock(&dl_b->lock); | |
726 | ||
727 | dl_b = &later_rq->rd->dl_bw; | |
728 | raw_spin_lock(&dl_b->lock); | |
729 | __dl_add(dl_b, p->dl.dl_bw, cpumask_weight(later_rq->rd->span)); | |
730 | raw_spin_unlock(&dl_b->lock); | |
731 | ||
fa9c9d10 | 732 | set_task_cpu(p, later_rq->cpu); |
a649f237 PZ |
733 | double_unlock_balance(later_rq, rq); |
734 | ||
735 | return later_rq; | |
fa9c9d10 WL |
736 | } |
737 | ||
1baca4ce JL |
738 | #else |
739 | ||
740 | static inline | |
741 | void enqueue_pushable_dl_task(struct rq *rq, struct task_struct *p) | |
742 | { | |
743 | } | |
744 | ||
745 | static inline | |
746 | void dequeue_pushable_dl_task(struct rq *rq, struct task_struct *p) | |
747 | { | |
748 | } | |
749 | ||
750 | static inline | |
751 | void inc_dl_migration(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq) | |
752 | { | |
753 | } | |
754 | ||
755 | static inline | |
756 | void dec_dl_migration(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq) | |
757 | { | |
758 | } | |
759 | ||
02d8ec94 | 760 | static inline void deadline_queue_push_tasks(struct rq *rq) |
dc877341 | 761 | { |
dc877341 PZ |
762 | } |
763 | ||
02d8ec94 | 764 | static inline void deadline_queue_pull_task(struct rq *rq) |
dc877341 PZ |
765 | { |
766 | } | |
1baca4ce JL |
767 | #endif /* CONFIG_SMP */ |
768 | ||
aab03e05 DF |
769 | static void enqueue_task_dl(struct rq *rq, struct task_struct *p, int flags); |
770 | static void __dequeue_task_dl(struct rq *rq, struct task_struct *p, int flags); | |
97fb7a0a | 771 | static void check_preempt_curr_dl(struct rq *rq, struct task_struct *p, int flags); |
aab03e05 | 772 | |
96458e7f SX |
773 | static inline void replenish_dl_new_period(struct sched_dl_entity *dl_se, |
774 | struct rq *rq) | |
775 | { | |
776 | /* for non-boosted task, pi_of(dl_se) == dl_se */ | |
777 | dl_se->deadline = rq_clock(rq) + pi_of(dl_se)->dl_deadline; | |
778 | dl_se->runtime = pi_of(dl_se)->dl_runtime; | |
779 | } | |
780 | ||
aab03e05 DF |
781 | /* |
782 | * We are being explicitly informed that a new instance is starting, | |
783 | * and this means that: | |
784 | * - the absolute deadline of the entity has to be placed at | |
785 | * current time + relative deadline; | |
786 | * - the runtime of the entity has to be set to the maximum value. | |
787 | * | |
788 | * The capability of specifying such event is useful whenever a -deadline | |
789 | * entity wants to (try to!) synchronize its behaviour with the scheduler's | |
790 | * one, and to (try to!) reconcile itself with its own scheduling | |
791 | * parameters. | |
792 | */ | |
98b0a857 | 793 | static inline void setup_new_dl_entity(struct sched_dl_entity *dl_se) |
aab03e05 DF |
794 | { |
795 | struct dl_rq *dl_rq = dl_rq_of_se(dl_se); | |
796 | struct rq *rq = rq_of_dl_rq(dl_rq); | |
797 | ||
2279f540 | 798 | WARN_ON(is_dl_boosted(dl_se)); |
72f9f3fd LA |
799 | WARN_ON(dl_time_before(rq_clock(rq), dl_se->deadline)); |
800 | ||
801 | /* | |
802 | * We are racing with the deadline timer. So, do nothing because | |
803 | * the deadline timer handler will take care of properly recharging | |
804 | * the runtime and postponing the deadline | |
805 | */ | |
806 | if (dl_se->dl_throttled) | |
807 | return; | |
aab03e05 DF |
808 | |
809 | /* | |
810 | * We use the regular wall clock time to set deadlines in the | |
811 | * future; in fact, we must consider execution overheads (time | |
812 | * spent on hardirq context, etc.). | |
813 | */ | |
96458e7f | 814 | replenish_dl_new_period(dl_se, rq); |
aab03e05 DF |
815 | } |
816 | ||
817 | /* | |
818 | * Pure Earliest Deadline First (EDF) scheduling does not deal with the | |
819 | * possibility of a entity lasting more than what it declared, and thus | |
820 | * exhausting its runtime. | |
821 | * | |
822 | * Here we are interested in making runtime overrun possible, but we do | |
823 | * not want a entity which is misbehaving to affect the scheduling of all | |
824 | * other entities. | |
825 | * Therefore, a budgeting strategy called Constant Bandwidth Server (CBS) | |
826 | * is used, in order to confine each entity within its own bandwidth. | |
827 | * | |
828 | * This function deals exactly with that, and ensures that when the runtime | |
829 | * of a entity is replenished, its deadline is also postponed. That ensures | |
830 | * the overrunning entity can't interfere with other entity in the system and | |
831 | * can't make them miss their deadlines. Reasons why this kind of overruns | |
832 | * could happen are, typically, a entity voluntarily trying to overcome its | |
1b09d29b | 833 | * runtime, or it just underestimated it during sched_setattr(). |
aab03e05 | 834 | */ |
2279f540 | 835 | static void replenish_dl_entity(struct sched_dl_entity *dl_se) |
aab03e05 DF |
836 | { |
837 | struct dl_rq *dl_rq = dl_rq_of_se(dl_se); | |
838 | struct rq *rq = rq_of_dl_rq(dl_rq); | |
839 | ||
09348d75 | 840 | WARN_ON_ONCE(pi_of(dl_se)->dl_runtime <= 0); |
2d3d891d DF |
841 | |
842 | /* | |
843 | * This could be the case for a !-dl task that is boosted. | |
844 | * Just go with full inherited parameters. | |
845 | */ | |
96458e7f SX |
846 | if (dl_se->dl_deadline == 0) |
847 | replenish_dl_new_period(dl_se, rq); | |
2d3d891d | 848 | |
48be3a67 PZ |
849 | if (dl_se->dl_yielded && dl_se->runtime > 0) |
850 | dl_se->runtime = 0; | |
851 | ||
aab03e05 DF |
852 | /* |
853 | * We keep moving the deadline away until we get some | |
854 | * available runtime for the entity. This ensures correct | |
855 | * handling of situations where the runtime overrun is | |
856 | * arbitrary large. | |
857 | */ | |
858 | while (dl_se->runtime <= 0) { | |
2279f540 JL |
859 | dl_se->deadline += pi_of(dl_se)->dl_period; |
860 | dl_se->runtime += pi_of(dl_se)->dl_runtime; | |
aab03e05 DF |
861 | } |
862 | ||
863 | /* | |
864 | * At this point, the deadline really should be "in | |
865 | * the future" with respect to rq->clock. If it's | |
866 | * not, we are, for some reason, lagging too much! | |
867 | * Anyway, after having warn userspace abut that, | |
868 | * we still try to keep the things running by | |
869 | * resetting the deadline and the budget of the | |
870 | * entity. | |
871 | */ | |
872 | if (dl_time_before(dl_se->deadline, rq_clock(rq))) { | |
c219b7dd | 873 | printk_deferred_once("sched: DL replenish lagged too much\n"); |
96458e7f | 874 | replenish_dl_new_period(dl_se, rq); |
aab03e05 | 875 | } |
1019a359 PZ |
876 | |
877 | if (dl_se->dl_yielded) | |
878 | dl_se->dl_yielded = 0; | |
879 | if (dl_se->dl_throttled) | |
880 | dl_se->dl_throttled = 0; | |
aab03e05 DF |
881 | } |
882 | ||
883 | /* | |
884 | * Here we check if --at time t-- an entity (which is probably being | |
885 | * [re]activated or, in general, enqueued) can use its remaining runtime | |
886 | * and its current deadline _without_ exceeding the bandwidth it is | |
887 | * assigned (function returns true if it can't). We are in fact applying | |
888 | * one of the CBS rules: when a task wakes up, if the residual runtime | |
889 | * over residual deadline fits within the allocated bandwidth, then we | |
890 | * can keep the current (absolute) deadline and residual budget without | |
891 | * disrupting the schedulability of the system. Otherwise, we should | |
892 | * refill the runtime and set the deadline a period in the future, | |
893 | * because keeping the current (absolute) deadline of the task would | |
712e5e34 | 894 | * result in breaking guarantees promised to other tasks (refer to |
d6a3b247 | 895 | * Documentation/scheduler/sched-deadline.rst for more information). |
aab03e05 DF |
896 | * |
897 | * This function returns true if: | |
898 | * | |
2317d5f1 | 899 | * runtime / (deadline - t) > dl_runtime / dl_deadline , |
aab03e05 DF |
900 | * |
901 | * IOW we can't recycle current parameters. | |
755378a4 | 902 | * |
2317d5f1 | 903 | * Notice that the bandwidth check is done against the deadline. For |
755378a4 | 904 | * task with deadline equal to period this is the same of using |
2317d5f1 | 905 | * dl_period instead of dl_deadline in the equation above. |
aab03e05 | 906 | */ |
2279f540 | 907 | static bool dl_entity_overflow(struct sched_dl_entity *dl_se, u64 t) |
aab03e05 DF |
908 | { |
909 | u64 left, right; | |
910 | ||
911 | /* | |
912 | * left and right are the two sides of the equation above, | |
913 | * after a bit of shuffling to use multiplications instead | |
914 | * of divisions. | |
915 | * | |
916 | * Note that none of the time values involved in the two | |
917 | * multiplications are absolute: dl_deadline and dl_runtime | |
918 | * are the relative deadline and the maximum runtime of each | |
919 | * instance, runtime is the runtime left for the last instance | |
920 | * and (deadline - t), since t is rq->clock, is the time left | |
921 | * to the (absolute) deadline. Even if overflowing the u64 type | |
922 | * is very unlikely to occur in both cases, here we scale down | |
923 | * as we want to avoid that risk at all. Scaling down by 10 | |
924 | * means that we reduce granularity to 1us. We are fine with it, | |
925 | * since this is only a true/false check and, anyway, thinking | |
926 | * of anything below microseconds resolution is actually fiction | |
927 | * (but still we want to give the user that illusion >;). | |
928 | */ | |
2279f540 | 929 | left = (pi_of(dl_se)->dl_deadline >> DL_SCALE) * (dl_se->runtime >> DL_SCALE); |
332ac17e | 930 | right = ((dl_se->deadline - t) >> DL_SCALE) * |
2279f540 | 931 | (pi_of(dl_se)->dl_runtime >> DL_SCALE); |
aab03e05 DF |
932 | |
933 | return dl_time_before(right, left); | |
934 | } | |
935 | ||
936 | /* | |
3effcb42 DBO |
937 | * Revised wakeup rule [1]: For self-suspending tasks, rather then |
938 | * re-initializing task's runtime and deadline, the revised wakeup | |
939 | * rule adjusts the task's runtime to avoid the task to overrun its | |
940 | * density. | |
aab03e05 | 941 | * |
3effcb42 DBO |
942 | * Reasoning: a task may overrun the density if: |
943 | * runtime / (deadline - t) > dl_runtime / dl_deadline | |
944 | * | |
945 | * Therefore, runtime can be adjusted to: | |
946 | * runtime = (dl_runtime / dl_deadline) * (deadline - t) | |
947 | * | |
948 | * In such way that runtime will be equal to the maximum density | |
949 | * the task can use without breaking any rule. | |
950 | * | |
951 | * [1] Luca Abeni, Giuseppe Lipari, and Juri Lelli. 2015. Constant | |
952 | * bandwidth server revisited. SIGBED Rev. 11, 4 (January 2015), 19-24. | |
953 | */ | |
954 | static void | |
955 | update_dl_revised_wakeup(struct sched_dl_entity *dl_se, struct rq *rq) | |
956 | { | |
957 | u64 laxity = dl_se->deadline - rq_clock(rq); | |
958 | ||
959 | /* | |
960 | * If the task has deadline < period, and the deadline is in the past, | |
961 | * it should already be throttled before this check. | |
962 | * | |
963 | * See update_dl_entity() comments for further details. | |
964 | */ | |
965 | WARN_ON(dl_time_before(dl_se->deadline, rq_clock(rq))); | |
966 | ||
967 | dl_se->runtime = (dl_se->dl_density * laxity) >> BW_SHIFT; | |
968 | } | |
969 | ||
970 | /* | |
971 | * Regarding the deadline, a task with implicit deadline has a relative | |
972 | * deadline == relative period. A task with constrained deadline has a | |
973 | * relative deadline <= relative period. | |
974 | * | |
975 | * We support constrained deadline tasks. However, there are some restrictions | |
976 | * applied only for tasks which do not have an implicit deadline. See | |
977 | * update_dl_entity() to know more about such restrictions. | |
978 | * | |
979 | * The dl_is_implicit() returns true if the task has an implicit deadline. | |
980 | */ | |
981 | static inline bool dl_is_implicit(struct sched_dl_entity *dl_se) | |
982 | { | |
983 | return dl_se->dl_deadline == dl_se->dl_period; | |
984 | } | |
985 | ||
986 | /* | |
987 | * When a deadline entity is placed in the runqueue, its runtime and deadline | |
988 | * might need to be updated. This is done by a CBS wake up rule. There are two | |
989 | * different rules: 1) the original CBS; and 2) the Revisited CBS. | |
990 | * | |
991 | * When the task is starting a new period, the Original CBS is used. In this | |
992 | * case, the runtime is replenished and a new absolute deadline is set. | |
993 | * | |
994 | * When a task is queued before the begin of the next period, using the | |
995 | * remaining runtime and deadline could make the entity to overflow, see | |
996 | * dl_entity_overflow() to find more about runtime overflow. When such case | |
997 | * is detected, the runtime and deadline need to be updated. | |
998 | * | |
999 | * If the task has an implicit deadline, i.e., deadline == period, the Original | |
1000 | * CBS is applied. the runtime is replenished and a new absolute deadline is | |
1001 | * set, as in the previous cases. | |
1002 | * | |
1003 | * However, the Original CBS does not work properly for tasks with | |
1004 | * deadline < period, which are said to have a constrained deadline. By | |
1005 | * applying the Original CBS, a constrained deadline task would be able to run | |
1006 | * runtime/deadline in a period. With deadline < period, the task would | |
1007 | * overrun the runtime/period allowed bandwidth, breaking the admission test. | |
1008 | * | |
1009 | * In order to prevent this misbehave, the Revisited CBS is used for | |
1010 | * constrained deadline tasks when a runtime overflow is detected. In the | |
1011 | * Revisited CBS, rather than replenishing & setting a new absolute deadline, | |
1012 | * the remaining runtime of the task is reduced to avoid runtime overflow. | |
1013 | * Please refer to the comments update_dl_revised_wakeup() function to find | |
1014 | * more about the Revised CBS rule. | |
aab03e05 | 1015 | */ |
2279f540 | 1016 | static void update_dl_entity(struct sched_dl_entity *dl_se) |
aab03e05 DF |
1017 | { |
1018 | struct dl_rq *dl_rq = dl_rq_of_se(dl_se); | |
1019 | struct rq *rq = rq_of_dl_rq(dl_rq); | |
1020 | ||
aab03e05 | 1021 | if (dl_time_before(dl_se->deadline, rq_clock(rq)) || |
2279f540 | 1022 | dl_entity_overflow(dl_se, rq_clock(rq))) { |
3effcb42 DBO |
1023 | |
1024 | if (unlikely(!dl_is_implicit(dl_se) && | |
1025 | !dl_time_before(dl_se->deadline, rq_clock(rq)) && | |
2279f540 | 1026 | !is_dl_boosted(dl_se))) { |
3effcb42 DBO |
1027 | update_dl_revised_wakeup(dl_se, rq); |
1028 | return; | |
1029 | } | |
1030 | ||
96458e7f | 1031 | replenish_dl_new_period(dl_se, rq); |
aab03e05 DF |
1032 | } |
1033 | } | |
1034 | ||
5ac69d37 DBO |
1035 | static inline u64 dl_next_period(struct sched_dl_entity *dl_se) |
1036 | { | |
1037 | return dl_se->deadline - dl_se->dl_deadline + dl_se->dl_period; | |
1038 | } | |
1039 | ||
aab03e05 DF |
1040 | /* |
1041 | * If the entity depleted all its runtime, and if we want it to sleep | |
1042 | * while waiting for some new execution time to become available, we | |
5ac69d37 | 1043 | * set the bandwidth replenishment timer to the replenishment instant |
aab03e05 DF |
1044 | * and try to activate it. |
1045 | * | |
1046 | * Notice that it is important for the caller to know if the timer | |
1047 | * actually started or not (i.e., the replenishment instant is in | |
1048 | * the future or in the past). | |
1049 | */ | |
a649f237 | 1050 | static int start_dl_timer(struct task_struct *p) |
aab03e05 | 1051 | { |
a649f237 PZ |
1052 | struct sched_dl_entity *dl_se = &p->dl; |
1053 | struct hrtimer *timer = &dl_se->dl_timer; | |
1054 | struct rq *rq = task_rq(p); | |
aab03e05 | 1055 | ktime_t now, act; |
aab03e05 DF |
1056 | s64 delta; |
1057 | ||
5cb9eaa3 | 1058 | lockdep_assert_rq_held(rq); |
a649f237 | 1059 | |
aab03e05 DF |
1060 | /* |
1061 | * We want the timer to fire at the deadline, but considering | |
1062 | * that it is actually coming from rq->clock and not from | |
1063 | * hrtimer's time base reading. | |
1064 | */ | |
5ac69d37 | 1065 | act = ns_to_ktime(dl_next_period(dl_se)); |
a649f237 | 1066 | now = hrtimer_cb_get_time(timer); |
aab03e05 DF |
1067 | delta = ktime_to_ns(now) - rq_clock(rq); |
1068 | act = ktime_add_ns(act, delta); | |
1069 | ||
1070 | /* | |
1071 | * If the expiry time already passed, e.g., because the value | |
1072 | * chosen as the deadline is too small, don't even try to | |
1073 | * start the timer in the past! | |
1074 | */ | |
1075 | if (ktime_us_delta(act, now) < 0) | |
1076 | return 0; | |
1077 | ||
a649f237 PZ |
1078 | /* |
1079 | * !enqueued will guarantee another callback; even if one is already in | |
1080 | * progress. This ensures a balanced {get,put}_task_struct(). | |
1081 | * | |
1082 | * The race against __run_timer() clearing the enqueued state is | |
1083 | * harmless because we're holding task_rq()->lock, therefore the timer | |
1084 | * expiring after we've done the check will wait on its task_rq_lock() | |
1085 | * and observe our state. | |
1086 | */ | |
1087 | if (!hrtimer_is_queued(timer)) { | |
1088 | get_task_struct(p); | |
d5096aa6 | 1089 | hrtimer_start(timer, act, HRTIMER_MODE_ABS_HARD); |
a649f237 | 1090 | } |
aab03e05 | 1091 | |
cc9684d3 | 1092 | return 1; |
aab03e05 DF |
1093 | } |
1094 | ||
1095 | /* | |
1096 | * This is the bandwidth enforcement timer callback. If here, we know | |
1097 | * a task is not on its dl_rq, since the fact that the timer was running | |
1098 | * means the task is throttled and needs a runtime replenishment. | |
1099 | * | |
1100 | * However, what we actually do depends on the fact the task is active, | |
1101 | * (it is on its rq) or has been removed from there by a call to | |
1102 | * dequeue_task_dl(). In the former case we must issue the runtime | |
1103 | * replenishment and add the task back to the dl_rq; in the latter, we just | |
1104 | * do nothing but clearing dl_throttled, so that runtime and deadline | |
1105 | * updating (and the queueing back to dl_rq) will be done by the | |
1106 | * next call to enqueue_task_dl(). | |
1107 | */ | |
1108 | static enum hrtimer_restart dl_task_timer(struct hrtimer *timer) | |
1109 | { | |
1110 | struct sched_dl_entity *dl_se = container_of(timer, | |
1111 | struct sched_dl_entity, | |
1112 | dl_timer); | |
1113 | struct task_struct *p = dl_task_of(dl_se); | |
eb580751 | 1114 | struct rq_flags rf; |
0f397f2c | 1115 | struct rq *rq; |
3960c8c0 | 1116 | |
eb580751 | 1117 | rq = task_rq_lock(p, &rf); |
0f397f2c | 1118 | |
aab03e05 | 1119 | /* |
a649f237 | 1120 | * The task might have changed its scheduling policy to something |
9846d50d | 1121 | * different than SCHED_DEADLINE (through switched_from_dl()). |
a649f237 | 1122 | */ |
209a0cbd | 1123 | if (!dl_task(p)) |
a649f237 | 1124 | goto unlock; |
a649f237 | 1125 | |
a649f237 PZ |
1126 | /* |
1127 | * The task might have been boosted by someone else and might be in the | |
1128 | * boosting/deboosting path, its not throttled. | |
1129 | */ | |
2279f540 | 1130 | if (is_dl_boosted(dl_se)) |
a649f237 | 1131 | goto unlock; |
a79ec89f | 1132 | |
fa9c9d10 | 1133 | /* |
a649f237 PZ |
1134 | * Spurious timer due to start_dl_timer() race; or we already received |
1135 | * a replenishment from rt_mutex_setprio(). | |
fa9c9d10 | 1136 | */ |
a649f237 | 1137 | if (!dl_se->dl_throttled) |
fa9c9d10 | 1138 | goto unlock; |
a649f237 PZ |
1139 | |
1140 | sched_clock_tick(); | |
1141 | update_rq_clock(rq); | |
fa9c9d10 | 1142 | |
a79ec89f KT |
1143 | /* |
1144 | * If the throttle happened during sched-out; like: | |
1145 | * | |
1146 | * schedule() | |
1147 | * deactivate_task() | |
1148 | * dequeue_task_dl() | |
1149 | * update_curr_dl() | |
1150 | * start_dl_timer() | |
1151 | * __dequeue_task_dl() | |
1152 | * prev->on_rq = 0; | |
1153 | * | |
1154 | * We can be both throttled and !queued. Replenish the counter | |
1155 | * but do not enqueue -- wait for our wakeup to do that. | |
1156 | */ | |
1157 | if (!task_on_rq_queued(p)) { | |
2279f540 | 1158 | replenish_dl_entity(dl_se); |
a79ec89f KT |
1159 | goto unlock; |
1160 | } | |
1161 | ||
1baca4ce | 1162 | #ifdef CONFIG_SMP |
c0c8c9fa | 1163 | if (unlikely(!rq->online)) { |
61c7aca6 WL |
1164 | /* |
1165 | * If the runqueue is no longer available, migrate the | |
1166 | * task elsewhere. This necessarily changes rq. | |
1167 | */ | |
9ef7e7e3 | 1168 | lockdep_unpin_lock(__rq_lockp(rq), rf.cookie); |
a649f237 | 1169 | rq = dl_task_offline_migration(rq, p); |
9ef7e7e3 | 1170 | rf.cookie = lockdep_pin_lock(__rq_lockp(rq)); |
dcc3b5ff | 1171 | update_rq_clock(rq); |
61c7aca6 WL |
1172 | |
1173 | /* | |
1174 | * Now that the task has been migrated to the new RQ and we | |
1175 | * have that locked, proceed as normal and enqueue the task | |
1176 | * there. | |
1177 | */ | |
c0c8c9fa | 1178 | } |
61c7aca6 | 1179 | #endif |
a649f237 | 1180 | |
61c7aca6 WL |
1181 | enqueue_task_dl(rq, p, ENQUEUE_REPLENISH); |
1182 | if (dl_task(rq->curr)) | |
1183 | check_preempt_curr_dl(rq, p, 0); | |
1184 | else | |
1185 | resched_curr(rq); | |
a649f237 | 1186 | |
61c7aca6 | 1187 | #ifdef CONFIG_SMP |
a649f237 PZ |
1188 | /* |
1189 | * Queueing this task back might have overloaded rq, check if we need | |
1190 | * to kick someone away. | |
1019a359 | 1191 | */ |
0aaafaab PZ |
1192 | if (has_pushable_dl_tasks(rq)) { |
1193 | /* | |
1194 | * Nothing relies on rq->lock after this, so its safe to drop | |
1195 | * rq->lock. | |
1196 | */ | |
d8ac8971 | 1197 | rq_unpin_lock(rq, &rf); |
1019a359 | 1198 | push_dl_task(rq); |
d8ac8971 | 1199 | rq_repin_lock(rq, &rf); |
0aaafaab | 1200 | } |
1baca4ce | 1201 | #endif |
a649f237 | 1202 | |
aab03e05 | 1203 | unlock: |
eb580751 | 1204 | task_rq_unlock(rq, p, &rf); |
aab03e05 | 1205 | |
a649f237 PZ |
1206 | /* |
1207 | * This can free the task_struct, including this hrtimer, do not touch | |
1208 | * anything related to that after this. | |
1209 | */ | |
1210 | put_task_struct(p); | |
1211 | ||
aab03e05 DF |
1212 | return HRTIMER_NORESTART; |
1213 | } | |
1214 | ||
1215 | void init_dl_task_timer(struct sched_dl_entity *dl_se) | |
1216 | { | |
1217 | struct hrtimer *timer = &dl_se->dl_timer; | |
1218 | ||
d5096aa6 | 1219 | hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD); |
aab03e05 DF |
1220 | timer->function = dl_task_timer; |
1221 | } | |
1222 | ||
df8eac8c DBO |
1223 | /* |
1224 | * During the activation, CBS checks if it can reuse the current task's | |
1225 | * runtime and period. If the deadline of the task is in the past, CBS | |
1226 | * cannot use the runtime, and so it replenishes the task. This rule | |
1227 | * works fine for implicit deadline tasks (deadline == period), and the | |
1228 | * CBS was designed for implicit deadline tasks. However, a task with | |
c4969417 | 1229 | * constrained deadline (deadline < period) might be awakened after the |
df8eac8c DBO |
1230 | * deadline, but before the next period. In this case, replenishing the |
1231 | * task would allow it to run for runtime / deadline. As in this case | |
1232 | * deadline < period, CBS enables a task to run for more than the | |
1233 | * runtime / period. In a very loaded system, this can cause a domino | |
1234 | * effect, making other tasks miss their deadlines. | |
1235 | * | |
1236 | * To avoid this problem, in the activation of a constrained deadline | |
1237 | * task after the deadline but before the next period, throttle the | |
1238 | * task and set the replenishing timer to the begin of the next period, | |
1239 | * unless it is boosted. | |
1240 | */ | |
1241 | static inline void dl_check_constrained_dl(struct sched_dl_entity *dl_se) | |
1242 | { | |
1243 | struct task_struct *p = dl_task_of(dl_se); | |
1244 | struct rq *rq = rq_of_dl_rq(dl_rq_of_se(dl_se)); | |
1245 | ||
1246 | if (dl_time_before(dl_se->deadline, rq_clock(rq)) && | |
1247 | dl_time_before(rq_clock(rq), dl_next_period(dl_se))) { | |
2279f540 | 1248 | if (unlikely(is_dl_boosted(dl_se) || !start_dl_timer(p))) |
df8eac8c DBO |
1249 | return; |
1250 | dl_se->dl_throttled = 1; | |
ae83b56a XP |
1251 | if (dl_se->runtime > 0) |
1252 | dl_se->runtime = 0; | |
df8eac8c DBO |
1253 | } |
1254 | } | |
1255 | ||
aab03e05 | 1256 | static |
6fab5410 | 1257 | int dl_runtime_exceeded(struct sched_dl_entity *dl_se) |
aab03e05 | 1258 | { |
269ad801 | 1259 | return (dl_se->runtime <= 0); |
aab03e05 DF |
1260 | } |
1261 | ||
c52f14d3 LA |
1262 | /* |
1263 | * This function implements the GRUB accounting rule: | |
1264 | * according to the GRUB reclaiming algorithm, the runtime is | |
daec5798 LA |
1265 | * not decreased as "dq = -dt", but as |
1266 | * "dq = -max{u / Umax, (1 - Uinact - Uextra)} dt", | |
1267 | * where u is the utilization of the task, Umax is the maximum reclaimable | |
1268 | * utilization, Uinact is the (per-runqueue) inactive utilization, computed | |
1269 | * as the difference between the "total runqueue utilization" and the | |
1270 | * runqueue active utilization, and Uextra is the (per runqueue) extra | |
1271 | * reclaimable utilization. | |
9f0d1a50 | 1272 | * Since rq->dl.running_bw and rq->dl.this_bw contain utilizations |
daec5798 LA |
1273 | * multiplied by 2^BW_SHIFT, the result has to be shifted right by |
1274 | * BW_SHIFT. | |
3b03706f | 1275 | * Since rq->dl.bw_ratio contains 1 / Umax multiplied by 2^RATIO_SHIFT, |
daec5798 LA |
1276 | * dl_bw is multiped by rq->dl.bw_ratio and shifted right by RATIO_SHIFT. |
1277 | * Since delta is a 64 bit variable, to have an overflow its value | |
1278 | * should be larger than 2^(64 - 20 - 8), which is more than 64 seconds. | |
1279 | * So, overflow is not an issue here. | |
c52f14d3 | 1280 | */ |
3febfc8a | 1281 | static u64 grub_reclaim(u64 delta, struct rq *rq, struct sched_dl_entity *dl_se) |
c52f14d3 | 1282 | { |
9f0d1a50 LA |
1283 | u64 u_inact = rq->dl.this_bw - rq->dl.running_bw; /* Utot - Uact */ |
1284 | u64 u_act; | |
daec5798 | 1285 | u64 u_act_min = (dl_se->dl_bw * rq->dl.bw_ratio) >> RATIO_SHIFT; |
c52f14d3 | 1286 | |
9f0d1a50 | 1287 | /* |
daec5798 LA |
1288 | * Instead of computing max{u * bw_ratio, (1 - u_inact - u_extra)}, |
1289 | * we compare u_inact + rq->dl.extra_bw with | |
1290 | * 1 - (u * rq->dl.bw_ratio >> RATIO_SHIFT), because | |
1291 | * u_inact + rq->dl.extra_bw can be larger than | |
1292 | * 1 * (so, 1 - u_inact - rq->dl.extra_bw would be negative | |
1293 | * leading to wrong results) | |
9f0d1a50 | 1294 | */ |
daec5798 LA |
1295 | if (u_inact + rq->dl.extra_bw > BW_UNIT - u_act_min) |
1296 | u_act = u_act_min; | |
9f0d1a50 | 1297 | else |
daec5798 | 1298 | u_act = BW_UNIT - u_inact - rq->dl.extra_bw; |
9f0d1a50 LA |
1299 | |
1300 | return (delta * u_act) >> BW_SHIFT; | |
c52f14d3 LA |
1301 | } |
1302 | ||
aab03e05 DF |
1303 | /* |
1304 | * Update the current task's runtime statistics (provided it is still | |
1305 | * a -deadline task and has not been removed from the dl_rq). | |
1306 | */ | |
1307 | static void update_curr_dl(struct rq *rq) | |
1308 | { | |
1309 | struct task_struct *curr = rq->curr; | |
1310 | struct sched_dl_entity *dl_se = &curr->dl; | |
07881166 JL |
1311 | u64 delta_exec, scaled_delta_exec; |
1312 | int cpu = cpu_of(rq); | |
6fe0ce1e | 1313 | u64 now; |
aab03e05 DF |
1314 | |
1315 | if (!dl_task(curr) || !on_dl_rq(dl_se)) | |
1316 | return; | |
1317 | ||
1318 | /* | |
1319 | * Consumed budget is computed considering the time as | |
1320 | * observed by schedulable tasks (excluding time spent | |
1321 | * in hardirq context, etc.). Deadlines are instead | |
1322 | * computed using hard walltime. This seems to be the more | |
1323 | * natural solution, but the full ramifications of this | |
1324 | * approach need further study. | |
1325 | */ | |
6fe0ce1e WY |
1326 | now = rq_clock_task(rq); |
1327 | delta_exec = now - curr->se.exec_start; | |
48be3a67 PZ |
1328 | if (unlikely((s64)delta_exec <= 0)) { |
1329 | if (unlikely(dl_se->dl_yielded)) | |
1330 | goto throttle; | |
734ff2a7 | 1331 | return; |
48be3a67 | 1332 | } |
aab03e05 | 1333 | |
ceeadb83 YS |
1334 | schedstat_set(curr->stats.exec_max, |
1335 | max(curr->stats.exec_max, delta_exec)); | |
aab03e05 | 1336 | |
95fd58e8 YS |
1337 | trace_sched_stat_runtime(curr, delta_exec, 0); |
1338 | ||
5531ecff | 1339 | update_current_exec_runtime(curr, now, delta_exec); |
aab03e05 | 1340 | |
794a56eb JL |
1341 | if (dl_entity_is_special(dl_se)) |
1342 | return; | |
1343 | ||
07881166 JL |
1344 | /* |
1345 | * For tasks that participate in GRUB, we implement GRUB-PA: the | |
1346 | * spare reclaimed bandwidth is used to clock down frequency. | |
1347 | * | |
1348 | * For the others, we still need to scale reservation parameters | |
1349 | * according to current frequency and CPU maximum capacity. | |
1350 | */ | |
1351 | if (unlikely(dl_se->flags & SCHED_FLAG_RECLAIM)) { | |
1352 | scaled_delta_exec = grub_reclaim(delta_exec, | |
1353 | rq, | |
1354 | &curr->dl); | |
1355 | } else { | |
1356 | unsigned long scale_freq = arch_scale_freq_capacity(cpu); | |
8ec59c0f | 1357 | unsigned long scale_cpu = arch_scale_cpu_capacity(cpu); |
07881166 JL |
1358 | |
1359 | scaled_delta_exec = cap_scale(delta_exec, scale_freq); | |
1360 | scaled_delta_exec = cap_scale(scaled_delta_exec, scale_cpu); | |
1361 | } | |
1362 | ||
1363 | dl_se->runtime -= scaled_delta_exec; | |
48be3a67 PZ |
1364 | |
1365 | throttle: | |
1366 | if (dl_runtime_exceeded(dl_se) || dl_se->dl_yielded) { | |
1019a359 | 1367 | dl_se->dl_throttled = 1; |
34be3930 JL |
1368 | |
1369 | /* If requested, inform the user about runtime overruns. */ | |
1370 | if (dl_runtime_exceeded(dl_se) && | |
1371 | (dl_se->flags & SCHED_FLAG_DL_OVERRUN)) | |
1372 | dl_se->dl_overrun = 1; | |
1373 | ||
aab03e05 | 1374 | __dequeue_task_dl(rq, curr, 0); |
2279f540 | 1375 | if (unlikely(is_dl_boosted(dl_se) || !start_dl_timer(curr))) |
aab03e05 DF |
1376 | enqueue_task_dl(rq, curr, ENQUEUE_REPLENISH); |
1377 | ||
1378 | if (!is_leftmost(curr, &rq->dl)) | |
8875125e | 1379 | resched_curr(rq); |
aab03e05 | 1380 | } |
1724813d PZ |
1381 | |
1382 | /* | |
1383 | * Because -- for now -- we share the rt bandwidth, we need to | |
1384 | * account our runtime there too, otherwise actual rt tasks | |
1385 | * would be able to exceed the shared quota. | |
1386 | * | |
1387 | * Account to the root rt group for now. | |
1388 | * | |
1389 | * The solution we're working towards is having the RT groups scheduled | |
1390 | * using deadline servers -- however there's a few nasties to figure | |
1391 | * out before that can happen. | |
1392 | */ | |
1393 | if (rt_bandwidth_enabled()) { | |
1394 | struct rt_rq *rt_rq = &rq->rt; | |
1395 | ||
1396 | raw_spin_lock(&rt_rq->rt_runtime_lock); | |
1724813d PZ |
1397 | /* |
1398 | * We'll let actual RT tasks worry about the overflow here, we | |
faa59937 JL |
1399 | * have our own CBS to keep us inline; only account when RT |
1400 | * bandwidth is relevant. | |
1724813d | 1401 | */ |
faa59937 JL |
1402 | if (sched_rt_bandwidth_account(rt_rq)) |
1403 | rt_rq->rt_time += delta_exec; | |
1724813d PZ |
1404 | raw_spin_unlock(&rt_rq->rt_runtime_lock); |
1405 | } | |
aab03e05 DF |
1406 | } |
1407 | ||
209a0cbd LA |
1408 | static enum hrtimer_restart inactive_task_timer(struct hrtimer *timer) |
1409 | { | |
1410 | struct sched_dl_entity *dl_se = container_of(timer, | |
1411 | struct sched_dl_entity, | |
1412 | inactive_timer); | |
1413 | struct task_struct *p = dl_task_of(dl_se); | |
1414 | struct rq_flags rf; | |
1415 | struct rq *rq; | |
1416 | ||
1417 | rq = task_rq_lock(p, &rf); | |
1418 | ||
ecda2b66 JL |
1419 | sched_clock_tick(); |
1420 | update_rq_clock(rq); | |
1421 | ||
2f064a59 | 1422 | if (!dl_task(p) || READ_ONCE(p->__state) == TASK_DEAD) { |
387e3130 LA |
1423 | struct dl_bw *dl_b = dl_bw_of(task_cpu(p)); |
1424 | ||
2f064a59 | 1425 | if (READ_ONCE(p->__state) == TASK_DEAD && dl_se->dl_non_contending) { |
794a56eb JL |
1426 | sub_running_bw(&p->dl, dl_rq_of_se(&p->dl)); |
1427 | sub_rq_bw(&p->dl, dl_rq_of_se(&p->dl)); | |
209a0cbd LA |
1428 | dl_se->dl_non_contending = 0; |
1429 | } | |
387e3130 LA |
1430 | |
1431 | raw_spin_lock(&dl_b->lock); | |
8c0944ce | 1432 | __dl_sub(dl_b, p->dl.dl_bw, dl_bw_cpus(task_cpu(p))); |
387e3130 | 1433 | raw_spin_unlock(&dl_b->lock); |
209a0cbd LA |
1434 | __dl_clear_params(p); |
1435 | ||
1436 | goto unlock; | |
1437 | } | |
1438 | if (dl_se->dl_non_contending == 0) | |
1439 | goto unlock; | |
1440 | ||
794a56eb | 1441 | sub_running_bw(dl_se, &rq->dl); |
209a0cbd LA |
1442 | dl_se->dl_non_contending = 0; |
1443 | unlock: | |
1444 | task_rq_unlock(rq, p, &rf); | |
1445 | put_task_struct(p); | |
1446 | ||
1447 | return HRTIMER_NORESTART; | |
1448 | } | |
1449 | ||
1450 | void init_dl_inactive_task_timer(struct sched_dl_entity *dl_se) | |
1451 | { | |
1452 | struct hrtimer *timer = &dl_se->inactive_timer; | |
1453 | ||
850377a8 | 1454 | hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD); |
209a0cbd LA |
1455 | timer->function = inactive_task_timer; |
1456 | } | |
1457 | ||
f4478e7c DE |
1458 | #define __node_2_dle(node) \ |
1459 | rb_entry((node), struct sched_dl_entity, rb_node) | |
1460 | ||
1baca4ce JL |
1461 | #ifdef CONFIG_SMP |
1462 | ||
1baca4ce JL |
1463 | static void inc_dl_deadline(struct dl_rq *dl_rq, u64 deadline) |
1464 | { | |
1465 | struct rq *rq = rq_of_dl_rq(dl_rq); | |
1466 | ||
1467 | if (dl_rq->earliest_dl.curr == 0 || | |
1468 | dl_time_before(deadline, dl_rq->earliest_dl.curr)) { | |
b13772f8 PZ |
1469 | if (dl_rq->earliest_dl.curr == 0) |
1470 | cpupri_set(&rq->rd->cpupri, rq->cpu, CPUPRI_HIGHER); | |
1baca4ce | 1471 | dl_rq->earliest_dl.curr = deadline; |
d8206bb3 | 1472 | cpudl_set(&rq->rd->cpudl, rq->cpu, deadline); |
1baca4ce JL |
1473 | } |
1474 | } | |
1475 | ||
1476 | static void dec_dl_deadline(struct dl_rq *dl_rq, u64 deadline) | |
1477 | { | |
1478 | struct rq *rq = rq_of_dl_rq(dl_rq); | |
1479 | ||
1480 | /* | |
1481 | * Since we may have removed our earliest (and/or next earliest) | |
1482 | * task we must recompute them. | |
1483 | */ | |
1484 | if (!dl_rq->dl_nr_running) { | |
1485 | dl_rq->earliest_dl.curr = 0; | |
1486 | dl_rq->earliest_dl.next = 0; | |
d8206bb3 | 1487 | cpudl_clear(&rq->rd->cpudl, rq->cpu); |
b13772f8 | 1488 | cpupri_set(&rq->rd->cpupri, rq->cpu, rq->rt.highest_prio.curr); |
1baca4ce | 1489 | } else { |
f4478e7c DE |
1490 | struct rb_node *leftmost = rb_first_cached(&dl_rq->root); |
1491 | struct sched_dl_entity *entry = __node_2_dle(leftmost); | |
1baca4ce | 1492 | |
1baca4ce | 1493 | dl_rq->earliest_dl.curr = entry->deadline; |
d8206bb3 | 1494 | cpudl_set(&rq->rd->cpudl, rq->cpu, entry->deadline); |
1baca4ce JL |
1495 | } |
1496 | } | |
1497 | ||
1498 | #else | |
1499 | ||
1500 | static inline void inc_dl_deadline(struct dl_rq *dl_rq, u64 deadline) {} | |
1501 | static inline void dec_dl_deadline(struct dl_rq *dl_rq, u64 deadline) {} | |
1502 | ||
1503 | #endif /* CONFIG_SMP */ | |
1504 | ||
1505 | static inline | |
1506 | void inc_dl_tasks(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq) | |
1507 | { | |
1508 | int prio = dl_task_of(dl_se)->prio; | |
1509 | u64 deadline = dl_se->deadline; | |
1510 | ||
1511 | WARN_ON(!dl_prio(prio)); | |
1512 | dl_rq->dl_nr_running++; | |
72465447 | 1513 | add_nr_running(rq_of_dl_rq(dl_rq), 1); |
1baca4ce JL |
1514 | |
1515 | inc_dl_deadline(dl_rq, deadline); | |
1516 | inc_dl_migration(dl_se, dl_rq); | |
1517 | } | |
1518 | ||
1519 | static inline | |
1520 | void dec_dl_tasks(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq) | |
1521 | { | |
1522 | int prio = dl_task_of(dl_se)->prio; | |
1523 | ||
1524 | WARN_ON(!dl_prio(prio)); | |
1525 | WARN_ON(!dl_rq->dl_nr_running); | |
1526 | dl_rq->dl_nr_running--; | |
72465447 | 1527 | sub_nr_running(rq_of_dl_rq(dl_rq), 1); |
1baca4ce JL |
1528 | |
1529 | dec_dl_deadline(dl_rq, dl_se->deadline); | |
1530 | dec_dl_migration(dl_se, dl_rq); | |
1531 | } | |
1532 | ||
8ecca394 PZ |
1533 | static inline bool __dl_less(struct rb_node *a, const struct rb_node *b) |
1534 | { | |
1535 | return dl_time_before(__node_2_dle(a)->deadline, __node_2_dle(b)->deadline); | |
1536 | } | |
1537 | ||
b5eb4a5f YS |
1538 | static inline struct sched_statistics * |
1539 | __schedstats_from_dl_se(struct sched_dl_entity *dl_se) | |
1540 | { | |
1541 | return &dl_task_of(dl_se)->stats; | |
1542 | } | |
1543 | ||
1544 | static inline void | |
1545 | update_stats_wait_start_dl(struct dl_rq *dl_rq, struct sched_dl_entity *dl_se) | |
1546 | { | |
1547 | struct sched_statistics *stats; | |
1548 | ||
1549 | if (!schedstat_enabled()) | |
1550 | return; | |
1551 | ||
1552 | stats = __schedstats_from_dl_se(dl_se); | |
1553 | __update_stats_wait_start(rq_of_dl_rq(dl_rq), dl_task_of(dl_se), stats); | |
1554 | } | |
1555 | ||
1556 | static inline void | |
1557 | update_stats_wait_end_dl(struct dl_rq *dl_rq, struct sched_dl_entity *dl_se) | |
1558 | { | |
1559 | struct sched_statistics *stats; | |
1560 | ||
1561 | if (!schedstat_enabled()) | |
1562 | return; | |
1563 | ||
1564 | stats = __schedstats_from_dl_se(dl_se); | |
1565 | __update_stats_wait_end(rq_of_dl_rq(dl_rq), dl_task_of(dl_se), stats); | |
1566 | } | |
1567 | ||
1568 | static inline void | |
1569 | update_stats_enqueue_sleeper_dl(struct dl_rq *dl_rq, struct sched_dl_entity *dl_se) | |
1570 | { | |
1571 | struct sched_statistics *stats; | |
1572 | ||
1573 | if (!schedstat_enabled()) | |
1574 | return; | |
1575 | ||
1576 | stats = __schedstats_from_dl_se(dl_se); | |
1577 | __update_stats_enqueue_sleeper(rq_of_dl_rq(dl_rq), dl_task_of(dl_se), stats); | |
1578 | } | |
1579 | ||
1580 | static inline void | |
1581 | update_stats_enqueue_dl(struct dl_rq *dl_rq, struct sched_dl_entity *dl_se, | |
1582 | int flags) | |
1583 | { | |
1584 | if (!schedstat_enabled()) | |
1585 | return; | |
1586 | ||
1587 | if (flags & ENQUEUE_WAKEUP) | |
1588 | update_stats_enqueue_sleeper_dl(dl_rq, dl_se); | |
1589 | } | |
1590 | ||
1591 | static inline void | |
1592 | update_stats_dequeue_dl(struct dl_rq *dl_rq, struct sched_dl_entity *dl_se, | |
1593 | int flags) | |
1594 | { | |
1595 | struct task_struct *p = dl_task_of(dl_se); | |
1596 | ||
1597 | if (!schedstat_enabled()) | |
1598 | return; | |
1599 | ||
1600 | if ((flags & DEQUEUE_SLEEP)) { | |
1601 | unsigned int state; | |
1602 | ||
1603 | state = READ_ONCE(p->__state); | |
1604 | if (state & TASK_INTERRUPTIBLE) | |
1605 | __schedstat_set(p->stats.sleep_start, | |
1606 | rq_clock(rq_of_dl_rq(dl_rq))); | |
1607 | ||
1608 | if (state & TASK_UNINTERRUPTIBLE) | |
1609 | __schedstat_set(p->stats.block_start, | |
1610 | rq_clock(rq_of_dl_rq(dl_rq))); | |
1611 | } | |
1612 | } | |
1613 | ||
aab03e05 DF |
1614 | static void __enqueue_dl_entity(struct sched_dl_entity *dl_se) |
1615 | { | |
1616 | struct dl_rq *dl_rq = dl_rq_of_se(dl_se); | |
aab03e05 | 1617 | |
09348d75 | 1618 | WARN_ON_ONCE(!RB_EMPTY_NODE(&dl_se->rb_node)); |
aab03e05 | 1619 | |
8ecca394 | 1620 | rb_add_cached(&dl_se->rb_node, &dl_rq->root, __dl_less); |
aab03e05 | 1621 | |
1baca4ce | 1622 | inc_dl_tasks(dl_se, dl_rq); |
aab03e05 DF |
1623 | } |
1624 | ||
1625 | static void __dequeue_dl_entity(struct sched_dl_entity *dl_se) | |
1626 | { | |
1627 | struct dl_rq *dl_rq = dl_rq_of_se(dl_se); | |
1628 | ||
1629 | if (RB_EMPTY_NODE(&dl_se->rb_node)) | |
1630 | return; | |
1631 | ||
2161573e | 1632 | rb_erase_cached(&dl_se->rb_node, &dl_rq->root); |
8ecca394 | 1633 | |
aab03e05 DF |
1634 | RB_CLEAR_NODE(&dl_se->rb_node); |
1635 | ||
1baca4ce | 1636 | dec_dl_tasks(dl_se, dl_rq); |
aab03e05 DF |
1637 | } |
1638 | ||
1639 | static void | |
2279f540 | 1640 | enqueue_dl_entity(struct sched_dl_entity *dl_se, int flags) |
aab03e05 | 1641 | { |
09348d75 | 1642 | WARN_ON_ONCE(on_dl_rq(dl_se)); |
aab03e05 | 1643 | |
b5eb4a5f YS |
1644 | update_stats_enqueue_dl(dl_rq_of_se(dl_se), dl_se, flags); |
1645 | ||
aab03e05 DF |
1646 | /* |
1647 | * If this is a wakeup or a new instance, the scheduling | |
1648 | * parameters of the task might need updating. Otherwise, | |
1649 | * we want a replenishment of its runtime. | |
1650 | */ | |
e36d8677 | 1651 | if (flags & ENQUEUE_WAKEUP) { |
8fd27231 | 1652 | task_contending(dl_se, flags); |
2279f540 | 1653 | update_dl_entity(dl_se); |
e36d8677 | 1654 | } else if (flags & ENQUEUE_REPLENISH) { |
2279f540 | 1655 | replenish_dl_entity(dl_se); |
295d6d5e LA |
1656 | } else if ((flags & ENQUEUE_RESTORE) && |
1657 | dl_time_before(dl_se->deadline, | |
1658 | rq_clock(rq_of_dl_rq(dl_rq_of_se(dl_se))))) { | |
1659 | setup_new_dl_entity(dl_se); | |
e36d8677 | 1660 | } |
aab03e05 DF |
1661 | |
1662 | __enqueue_dl_entity(dl_se); | |
1663 | } | |
1664 | ||
1665 | static void dequeue_dl_entity(struct sched_dl_entity *dl_se) | |
1666 | { | |
1667 | __dequeue_dl_entity(dl_se); | |
1668 | } | |
1669 | ||
1670 | static void enqueue_task_dl(struct rq *rq, struct task_struct *p, int flags) | |
1671 | { | |
2279f540 | 1672 | if (is_dl_boosted(&p->dl)) { |
feff2e65 DBO |
1673 | /* |
1674 | * Because of delays in the detection of the overrun of a | |
1675 | * thread's runtime, it might be the case that a thread | |
1676 | * goes to sleep in a rt mutex with negative runtime. As | |
1677 | * a consequence, the thread will be throttled. | |
1678 | * | |
1679 | * While waiting for the mutex, this thread can also be | |
1680 | * boosted via PI, resulting in a thread that is throttled | |
1681 | * and boosted at the same time. | |
1682 | * | |
1683 | * In this case, the boost overrides the throttle. | |
1684 | */ | |
1685 | if (p->dl.dl_throttled) { | |
1686 | /* | |
1687 | * The replenish timer needs to be canceled. No | |
1688 | * problem if it fires concurrently: boosted threads | |
1689 | * are ignored in dl_task_timer(). | |
1690 | */ | |
1691 | hrtimer_try_to_cancel(&p->dl.dl_timer); | |
1692 | p->dl.dl_throttled = 0; | |
1693 | } | |
64be6f1f JL |
1694 | } else if (!dl_prio(p->normal_prio)) { |
1695 | /* | |
46fcc4b0 LS |
1696 | * Special case in which we have a !SCHED_DEADLINE task that is going |
1697 | * to be deboosted, but exceeds its runtime while doing so. No point in | |
1698 | * replenishing it, as it's going to return back to its original | |
1699 | * scheduling class after this. If it has been throttled, we need to | |
1700 | * clear the flag, otherwise the task may wake up as throttled after | |
1701 | * being boosted again with no means to replenish the runtime and clear | |
1702 | * the throttle. | |
64be6f1f | 1703 | */ |
46fcc4b0 | 1704 | p->dl.dl_throttled = 0; |
ddfc7103 JL |
1705 | if (!(flags & ENQUEUE_REPLENISH)) |
1706 | printk_deferred_once("sched: DL de-boosted task PID %d: REPLENISH flag missing\n", | |
1707 | task_pid_nr(p)); | |
1708 | ||
64be6f1f JL |
1709 | return; |
1710 | } | |
2d3d891d | 1711 | |
df8eac8c DBO |
1712 | /* |
1713 | * Check if a constrained deadline task was activated | |
1714 | * after the deadline but before the next period. | |
1715 | * If that is the case, the task will be throttled and | |
1716 | * the replenishment timer will be set to the next period. | |
1717 | */ | |
3effcb42 | 1718 | if (!p->dl.dl_throttled && !dl_is_implicit(&p->dl)) |
df8eac8c DBO |
1719 | dl_check_constrained_dl(&p->dl); |
1720 | ||
8fd27231 | 1721 | if (p->on_rq == TASK_ON_RQ_MIGRATING || flags & ENQUEUE_RESTORE) { |
794a56eb JL |
1722 | add_rq_bw(&p->dl, &rq->dl); |
1723 | add_running_bw(&p->dl, &rq->dl); | |
8fd27231 | 1724 | } |
e36d8677 | 1725 | |
aab03e05 | 1726 | /* |
e36d8677 | 1727 | * If p is throttled, we do not enqueue it. In fact, if it exhausted |
aab03e05 DF |
1728 | * its budget it needs a replenishment and, since it now is on |
1729 | * its rq, the bandwidth timer callback (which clearly has not | |
1730 | * run yet) will take care of this. | |
e36d8677 LA |
1731 | * However, the active utilization does not depend on the fact |
1732 | * that the task is on the runqueue or not (but depends on the | |
1733 | * task's state - in GRUB parlance, "inactive" vs "active contending"). | |
1734 | * In other words, even if a task is throttled its utilization must | |
1735 | * be counted in the active utilization; hence, we need to call | |
1736 | * add_running_bw(). | |
aab03e05 | 1737 | */ |
e36d8677 | 1738 | if (p->dl.dl_throttled && !(flags & ENQUEUE_REPLENISH)) { |
209a0cbd | 1739 | if (flags & ENQUEUE_WAKEUP) |
8fd27231 | 1740 | task_contending(&p->dl, flags); |
209a0cbd | 1741 | |
aab03e05 | 1742 | return; |
e36d8677 | 1743 | } |
aab03e05 | 1744 | |
b5eb4a5f YS |
1745 | check_schedstat_required(); |
1746 | update_stats_wait_start_dl(dl_rq_of_se(&p->dl), &p->dl); | |
1747 | ||
2279f540 | 1748 | enqueue_dl_entity(&p->dl, flags); |
1baca4ce | 1749 | |
4b53a341 | 1750 | if (!task_current(rq, p) && p->nr_cpus_allowed > 1) |
1baca4ce | 1751 | enqueue_pushable_dl_task(rq, p); |
aab03e05 DF |
1752 | } |
1753 | ||
1754 | static void __dequeue_task_dl(struct rq *rq, struct task_struct *p, int flags) | |
1755 | { | |
b5eb4a5f | 1756 | update_stats_dequeue_dl(&rq->dl, &p->dl, flags); |
aab03e05 | 1757 | dequeue_dl_entity(&p->dl); |
1baca4ce | 1758 | dequeue_pushable_dl_task(rq, p); |
aab03e05 DF |
1759 | } |
1760 | ||
1761 | static void dequeue_task_dl(struct rq *rq, struct task_struct *p, int flags) | |
1762 | { | |
1763 | update_curr_dl(rq); | |
1764 | __dequeue_task_dl(rq, p, flags); | |
e36d8677 | 1765 | |
8fd27231 | 1766 | if (p->on_rq == TASK_ON_RQ_MIGRATING || flags & DEQUEUE_SAVE) { |
794a56eb JL |
1767 | sub_running_bw(&p->dl, &rq->dl); |
1768 | sub_rq_bw(&p->dl, &rq->dl); | |
8fd27231 | 1769 | } |
e36d8677 LA |
1770 | |
1771 | /* | |
209a0cbd LA |
1772 | * This check allows to start the inactive timer (or to immediately |
1773 | * decrease the active utilization, if needed) in two cases: | |
e36d8677 LA |
1774 | * when the task blocks and when it is terminating |
1775 | * (p->state == TASK_DEAD). We can handle the two cases in the same | |
1776 | * way, because from GRUB's point of view the same thing is happening | |
1777 | * (the task moves from "active contending" to "active non contending" | |
1778 | * or "inactive") | |
1779 | */ | |
1780 | if (flags & DEQUEUE_SLEEP) | |
209a0cbd | 1781 | task_non_contending(p); |
aab03e05 DF |
1782 | } |
1783 | ||
1784 | /* | |
1785 | * Yield task semantic for -deadline tasks is: | |
1786 | * | |
1787 | * get off from the CPU until our next instance, with | |
1788 | * a new runtime. This is of little use now, since we | |
1789 | * don't have a bandwidth reclaiming mechanism. Anyway, | |
1790 | * bandwidth reclaiming is planned for the future, and | |
1791 | * yield_task_dl will indicate that some spare budget | |
1792 | * is available for other task instances to use it. | |
1793 | */ | |
1794 | static void yield_task_dl(struct rq *rq) | |
1795 | { | |
aab03e05 DF |
1796 | /* |
1797 | * We make the task go to sleep until its current deadline by | |
1798 | * forcing its runtime to zero. This way, update_curr_dl() stops | |
1799 | * it and the bandwidth timer will wake it up and will give it | |
5bfd126e | 1800 | * new scheduling parameters (thanks to dl_yielded=1). |
aab03e05 | 1801 | */ |
48be3a67 PZ |
1802 | rq->curr->dl.dl_yielded = 1; |
1803 | ||
6f1607f1 | 1804 | update_rq_clock(rq); |
aab03e05 | 1805 | update_curr_dl(rq); |
44fb085b WL |
1806 | /* |
1807 | * Tell update_rq_clock() that we've just updated, | |
1808 | * so we don't do microscopic update in schedule() | |
1809 | * and double the fastpath cost. | |
1810 | */ | |
adcc8da8 | 1811 | rq_clock_skip_update(rq); |
aab03e05 DF |
1812 | } |
1813 | ||
1baca4ce JL |
1814 | #ifdef CONFIG_SMP |
1815 | ||
973bee49 SX |
1816 | static inline bool dl_task_is_earliest_deadline(struct task_struct *p, |
1817 | struct rq *rq) | |
1818 | { | |
1819 | return (!rq->dl.dl_nr_running || | |
1820 | dl_time_before(p->dl.deadline, | |
1821 | rq->dl.earliest_dl.curr)); | |
1822 | } | |
1823 | ||
1baca4ce | 1824 | static int find_later_rq(struct task_struct *task); |
1baca4ce JL |
1825 | |
1826 | static int | |
3aef1551 | 1827 | select_task_rq_dl(struct task_struct *p, int cpu, int flags) |
1baca4ce JL |
1828 | { |
1829 | struct task_struct *curr; | |
b4118988 | 1830 | bool select_rq; |
1baca4ce JL |
1831 | struct rq *rq; |
1832 | ||
3aef1551 | 1833 | if (!(flags & WF_TTWU)) |
1baca4ce JL |
1834 | goto out; |
1835 | ||
1836 | rq = cpu_rq(cpu); | |
1837 | ||
1838 | rcu_read_lock(); | |
316c1608 | 1839 | curr = READ_ONCE(rq->curr); /* unlocked access */ |
1baca4ce JL |
1840 | |
1841 | /* | |
1842 | * If we are dealing with a -deadline task, we must | |
1843 | * decide where to wake it up. | |
1844 | * If it has a later deadline and the current task | |
1845 | * on this rq can't move (provided the waking task | |
1846 | * can!) we prefer to send it somewhere else. On the | |
1847 | * other hand, if it has a shorter deadline, we | |
1848 | * try to make it stay here, it might be important. | |
1849 | */ | |
b4118988 LA |
1850 | select_rq = unlikely(dl_task(curr)) && |
1851 | (curr->nr_cpus_allowed < 2 || | |
1852 | !dl_entity_preempt(&p->dl, &curr->dl)) && | |
1853 | p->nr_cpus_allowed > 1; | |
1854 | ||
1855 | /* | |
1856 | * Take the capacity of the CPU into account to | |
1857 | * ensure it fits the requirement of the task. | |
1858 | */ | |
740cf8a7 | 1859 | if (sched_asym_cpucap_active()) |
b4118988 LA |
1860 | select_rq |= !dl_task_fits_capacity(p, cpu); |
1861 | ||
1862 | if (select_rq) { | |
1baca4ce JL |
1863 | int target = find_later_rq(p); |
1864 | ||
9d514262 | 1865 | if (target != -1 && |
973bee49 | 1866 | dl_task_is_earliest_deadline(p, cpu_rq(target))) |
1baca4ce JL |
1867 | cpu = target; |
1868 | } | |
1869 | rcu_read_unlock(); | |
1870 | ||
1871 | out: | |
1872 | return cpu; | |
1873 | } | |
1874 | ||
1327237a | 1875 | static void migrate_task_rq_dl(struct task_struct *p, int new_cpu __maybe_unused) |
209a0cbd | 1876 | { |
2679a837 | 1877 | struct rq_flags rf; |
209a0cbd LA |
1878 | struct rq *rq; |
1879 | ||
2f064a59 | 1880 | if (READ_ONCE(p->__state) != TASK_WAKING) |
209a0cbd LA |
1881 | return; |
1882 | ||
1883 | rq = task_rq(p); | |
1884 | /* | |
1885 | * Since p->state == TASK_WAKING, set_task_cpu() has been called | |
1886 | * from try_to_wake_up(). Hence, p->pi_lock is locked, but | |
1887 | * rq->lock is not... So, lock it | |
1888 | */ | |
2679a837 | 1889 | rq_lock(rq, &rf); |
8fd27231 | 1890 | if (p->dl.dl_non_contending) { |
b4da13aa | 1891 | update_rq_clock(rq); |
794a56eb | 1892 | sub_running_bw(&p->dl, &rq->dl); |
8fd27231 LA |
1893 | p->dl.dl_non_contending = 0; |
1894 | /* | |
1895 | * If the timer handler is currently running and the | |
3b03706f | 1896 | * timer cannot be canceled, inactive_task_timer() |
8fd27231 LA |
1897 | * will see that dl_not_contending is not set, and |
1898 | * will not touch the rq's active utilization, | |
1899 | * so we are still safe. | |
1900 | */ | |
1901 | if (hrtimer_try_to_cancel(&p->dl.inactive_timer) == 1) | |
1902 | put_task_struct(p); | |
1903 | } | |
794a56eb | 1904 | sub_rq_bw(&p->dl, &rq->dl); |
2679a837 | 1905 | rq_unlock(rq, &rf); |
209a0cbd LA |
1906 | } |
1907 | ||
1baca4ce JL |
1908 | static void check_preempt_equal_dl(struct rq *rq, struct task_struct *p) |
1909 | { | |
1910 | /* | |
1911 | * Current can't be migrated, useless to reschedule, | |
1912 | * let's hope p can move out. | |
1913 | */ | |
4b53a341 | 1914 | if (rq->curr->nr_cpus_allowed == 1 || |
3261ed0b | 1915 | !cpudl_find(&rq->rd->cpudl, rq->curr, NULL)) |
1baca4ce JL |
1916 | return; |
1917 | ||
1918 | /* | |
1919 | * p is migratable, so let's not schedule it and | |
1920 | * see if it is pushed or pulled somewhere else. | |
1921 | */ | |
4b53a341 | 1922 | if (p->nr_cpus_allowed != 1 && |
3261ed0b | 1923 | cpudl_find(&rq->rd->cpudl, p, NULL)) |
1baca4ce JL |
1924 | return; |
1925 | ||
8875125e | 1926 | resched_curr(rq); |
1baca4ce JL |
1927 | } |
1928 | ||
6e2df058 PZ |
1929 | static int balance_dl(struct rq *rq, struct task_struct *p, struct rq_flags *rf) |
1930 | { | |
1931 | if (!on_dl_rq(&p->dl) && need_pull_dl_task(rq, p)) { | |
1932 | /* | |
1933 | * This is OK, because current is on_cpu, which avoids it being | |
1934 | * picked for load-balance and preemption/IRQs are still | |
1935 | * disabled avoiding further scheduler activity on it and we've | |
1936 | * not yet started the picking loop. | |
1937 | */ | |
1938 | rq_unpin_lock(rq, rf); | |
1939 | pull_dl_task(rq); | |
1940 | rq_repin_lock(rq, rf); | |
1941 | } | |
1942 | ||
1943 | return sched_stop_runnable(rq) || sched_dl_runnable(rq); | |
1944 | } | |
1baca4ce JL |
1945 | #endif /* CONFIG_SMP */ |
1946 | ||
aab03e05 DF |
1947 | /* |
1948 | * Only called when both the current and waking task are -deadline | |
1949 | * tasks. | |
1950 | */ | |
1951 | static void check_preempt_curr_dl(struct rq *rq, struct task_struct *p, | |
1952 | int flags) | |
1953 | { | |
1baca4ce | 1954 | if (dl_entity_preempt(&p->dl, &rq->curr->dl)) { |
8875125e | 1955 | resched_curr(rq); |
1baca4ce JL |
1956 | return; |
1957 | } | |
1958 | ||
1959 | #ifdef CONFIG_SMP | |
1960 | /* | |
1961 | * In the unlikely case current and p have the same deadline | |
1962 | * let us try to decide what's the best thing to do... | |
1963 | */ | |
332ac17e DF |
1964 | if ((p->dl.deadline == rq->curr->dl.deadline) && |
1965 | !test_tsk_need_resched(rq->curr)) | |
1baca4ce JL |
1966 | check_preempt_equal_dl(rq, p); |
1967 | #endif /* CONFIG_SMP */ | |
aab03e05 DF |
1968 | } |
1969 | ||
1970 | #ifdef CONFIG_SCHED_HRTICK | |
1971 | static void start_hrtick_dl(struct rq *rq, struct task_struct *p) | |
1972 | { | |
177ef2a6 | 1973 | hrtick_start(rq, p->dl.runtime); |
aab03e05 | 1974 | } |
36ce9881 WL |
1975 | #else /* !CONFIG_SCHED_HRTICK */ |
1976 | static void start_hrtick_dl(struct rq *rq, struct task_struct *p) | |
1977 | { | |
1978 | } | |
aab03e05 DF |
1979 | #endif |
1980 | ||
a0e813f2 | 1981 | static void set_next_task_dl(struct rq *rq, struct task_struct *p, bool first) |
ff1cdc94 | 1982 | { |
b5eb4a5f YS |
1983 | struct sched_dl_entity *dl_se = &p->dl; |
1984 | struct dl_rq *dl_rq = &rq->dl; | |
1985 | ||
ff1cdc94 | 1986 | p->se.exec_start = rq_clock_task(rq); |
b5eb4a5f YS |
1987 | if (on_dl_rq(&p->dl)) |
1988 | update_stats_wait_end_dl(dl_rq, dl_se); | |
ff1cdc94 MS |
1989 | |
1990 | /* You can't push away the running task */ | |
1991 | dequeue_pushable_dl_task(rq, p); | |
f95d4eae | 1992 | |
a0e813f2 PZ |
1993 | if (!first) |
1994 | return; | |
1995 | ||
e0ee463c | 1996 | if (hrtick_enabled_dl(rq)) |
f95d4eae PZ |
1997 | start_hrtick_dl(rq, p); |
1998 | ||
1999 | if (rq->curr->sched_class != &dl_sched_class) | |
2000 | update_dl_rq_load_avg(rq_clock_pelt(rq), rq, 0); | |
2001 | ||
2002 | deadline_queue_push_tasks(rq); | |
ff1cdc94 MS |
2003 | } |
2004 | ||
821aecd0 | 2005 | static struct sched_dl_entity *pick_next_dl_entity(struct dl_rq *dl_rq) |
aab03e05 | 2006 | { |
2161573e | 2007 | struct rb_node *left = rb_first_cached(&dl_rq->root); |
aab03e05 DF |
2008 | |
2009 | if (!left) | |
2010 | return NULL; | |
2011 | ||
f4478e7c | 2012 | return __node_2_dle(left); |
aab03e05 DF |
2013 | } |
2014 | ||
21f56ffe | 2015 | static struct task_struct *pick_task_dl(struct rq *rq) |
aab03e05 DF |
2016 | { |
2017 | struct sched_dl_entity *dl_se; | |
6e2df058 | 2018 | struct dl_rq *dl_rq = &rq->dl; |
aab03e05 | 2019 | struct task_struct *p; |
aab03e05 | 2020 | |
6e2df058 | 2021 | if (!sched_dl_runnable(rq)) |
aab03e05 DF |
2022 | return NULL; |
2023 | ||
821aecd0 | 2024 | dl_se = pick_next_dl_entity(dl_rq); |
09348d75 | 2025 | WARN_ON_ONCE(!dl_se); |
aab03e05 | 2026 | p = dl_task_of(dl_se); |
21f56ffe PZ |
2027 | |
2028 | return p; | |
2029 | } | |
2030 | ||
2031 | static struct task_struct *pick_next_task_dl(struct rq *rq) | |
2032 | { | |
2033 | struct task_struct *p; | |
2034 | ||
2035 | p = pick_task_dl(rq); | |
2036 | if (p) | |
2037 | set_next_task_dl(rq, p, true); | |
2038 | ||
aab03e05 DF |
2039 | return p; |
2040 | } | |
2041 | ||
6e2df058 | 2042 | static void put_prev_task_dl(struct rq *rq, struct task_struct *p) |
aab03e05 | 2043 | { |
b5eb4a5f YS |
2044 | struct sched_dl_entity *dl_se = &p->dl; |
2045 | struct dl_rq *dl_rq = &rq->dl; | |
2046 | ||
2047 | if (on_dl_rq(&p->dl)) | |
2048 | update_stats_wait_start_dl(dl_rq, dl_se); | |
2049 | ||
aab03e05 | 2050 | update_curr_dl(rq); |
1baca4ce | 2051 | |
23127296 | 2052 | update_dl_rq_load_avg(rq_clock_pelt(rq), rq, 1); |
4b53a341 | 2053 | if (on_dl_rq(&p->dl) && p->nr_cpus_allowed > 1) |
1baca4ce | 2054 | enqueue_pushable_dl_task(rq, p); |
aab03e05 DF |
2055 | } |
2056 | ||
d84b3131 FW |
2057 | /* |
2058 | * scheduler tick hitting a task of our scheduling class. | |
2059 | * | |
2060 | * NOTE: This function can be called remotely by the tick offload that | |
2061 | * goes along full dynticks. Therefore no local assumption can be made | |
2062 | * and everything must be accessed through the @rq and @curr passed in | |
2063 | * parameters. | |
2064 | */ | |
aab03e05 DF |
2065 | static void task_tick_dl(struct rq *rq, struct task_struct *p, int queued) |
2066 | { | |
2067 | update_curr_dl(rq); | |
2068 | ||
23127296 | 2069 | update_dl_rq_load_avg(rq_clock_pelt(rq), rq, 1); |
a7bebf48 WL |
2070 | /* |
2071 | * Even when we have runtime, update_curr_dl() might have resulted in us | |
2072 | * not being the leftmost task anymore. In that case NEED_RESCHED will | |
2073 | * be set and schedule() will start a new hrtick for the next task. | |
2074 | */ | |
e0ee463c | 2075 | if (hrtick_enabled_dl(rq) && queued && p->dl.runtime > 0 && |
a7bebf48 | 2076 | is_leftmost(p, &rq->dl)) |
aab03e05 | 2077 | start_hrtick_dl(rq, p); |
aab03e05 DF |
2078 | } |
2079 | ||
2080 | static void task_fork_dl(struct task_struct *p) | |
2081 | { | |
2082 | /* | |
2083 | * SCHED_DEADLINE tasks cannot fork and this is achieved through | |
2084 | * sched_fork() | |
2085 | */ | |
2086 | } | |
2087 | ||
1baca4ce JL |
2088 | #ifdef CONFIG_SMP |
2089 | ||
2090 | /* Only try algorithms three times */ | |
2091 | #define DL_MAX_TRIES 3 | |
2092 | ||
2093 | static int pick_dl_task(struct rq *rq, struct task_struct *p, int cpu) | |
2094 | { | |
2095 | if (!task_running(rq, p) && | |
95158a89 | 2096 | cpumask_test_cpu(cpu, &p->cpus_mask)) |
1baca4ce | 2097 | return 1; |
1baca4ce JL |
2098 | return 0; |
2099 | } | |
2100 | ||
8b5e770e WL |
2101 | /* |
2102 | * Return the earliest pushable rq's task, which is suitable to be executed | |
2103 | * on the CPU, NULL otherwise: | |
2104 | */ | |
2105 | static struct task_struct *pick_earliest_pushable_dl_task(struct rq *rq, int cpu) | |
2106 | { | |
8b5e770e | 2107 | struct task_struct *p = NULL; |
f4478e7c | 2108 | struct rb_node *next_node; |
8b5e770e WL |
2109 | |
2110 | if (!has_pushable_dl_tasks(rq)) | |
2111 | return NULL; | |
2112 | ||
f4478e7c DE |
2113 | next_node = rb_first_cached(&rq->dl.pushable_dl_tasks_root); |
2114 | ||
8b5e770e WL |
2115 | next_node: |
2116 | if (next_node) { | |
f4478e7c | 2117 | p = __node_2_pdl(next_node); |
8b5e770e WL |
2118 | |
2119 | if (pick_dl_task(rq, p, cpu)) | |
2120 | return p; | |
2121 | ||
2122 | next_node = rb_next(next_node); | |
2123 | goto next_node; | |
2124 | } | |
2125 | ||
2126 | return NULL; | |
2127 | } | |
2128 | ||
1baca4ce JL |
2129 | static DEFINE_PER_CPU(cpumask_var_t, local_cpu_mask_dl); |
2130 | ||
2131 | static int find_later_rq(struct task_struct *task) | |
2132 | { | |
2133 | struct sched_domain *sd; | |
4ba29684 | 2134 | struct cpumask *later_mask = this_cpu_cpumask_var_ptr(local_cpu_mask_dl); |
1baca4ce | 2135 | int this_cpu = smp_processor_id(); |
b18c3ca1 | 2136 | int cpu = task_cpu(task); |
1baca4ce JL |
2137 | |
2138 | /* Make sure the mask is initialized first */ | |
2139 | if (unlikely(!later_mask)) | |
2140 | return -1; | |
2141 | ||
4b53a341 | 2142 | if (task->nr_cpus_allowed == 1) |
1baca4ce JL |
2143 | return -1; |
2144 | ||
91ec6778 JL |
2145 | /* |
2146 | * We have to consider system topology and task affinity | |
97fb7a0a | 2147 | * first, then we can look for a suitable CPU. |
91ec6778 | 2148 | */ |
3261ed0b | 2149 | if (!cpudl_find(&task_rq(task)->rd->cpudl, task, later_mask)) |
1baca4ce JL |
2150 | return -1; |
2151 | ||
2152 | /* | |
b18c3ca1 BP |
2153 | * If we are here, some targets have been found, including |
2154 | * the most suitable which is, among the runqueues where the | |
2155 | * current tasks have later deadlines than the task's one, the | |
2156 | * rq with the latest possible one. | |
1baca4ce JL |
2157 | * |
2158 | * Now we check how well this matches with task's | |
2159 | * affinity and system topology. | |
2160 | * | |
97fb7a0a | 2161 | * The last CPU where the task run is our first |
1baca4ce JL |
2162 | * guess, since it is most likely cache-hot there. |
2163 | */ | |
2164 | if (cpumask_test_cpu(cpu, later_mask)) | |
2165 | return cpu; | |
2166 | /* | |
2167 | * Check if this_cpu is to be skipped (i.e., it is | |
2168 | * not in the mask) or not. | |
2169 | */ | |
2170 | if (!cpumask_test_cpu(this_cpu, later_mask)) | |
2171 | this_cpu = -1; | |
2172 | ||
2173 | rcu_read_lock(); | |
2174 | for_each_domain(cpu, sd) { | |
2175 | if (sd->flags & SD_WAKE_AFFINE) { | |
b18c3ca1 | 2176 | int best_cpu; |
1baca4ce JL |
2177 | |
2178 | /* | |
2179 | * If possible, preempting this_cpu is | |
2180 | * cheaper than migrating. | |
2181 | */ | |
2182 | if (this_cpu != -1 && | |
2183 | cpumask_test_cpu(this_cpu, sched_domain_span(sd))) { | |
2184 | rcu_read_unlock(); | |
2185 | return this_cpu; | |
2186 | } | |
2187 | ||
14e292f8 PZ |
2188 | best_cpu = cpumask_any_and_distribute(later_mask, |
2189 | sched_domain_span(sd)); | |
1baca4ce | 2190 | /* |
97fb7a0a | 2191 | * Last chance: if a CPU being in both later_mask |
b18c3ca1 | 2192 | * and current sd span is valid, that becomes our |
97fb7a0a | 2193 | * choice. Of course, the latest possible CPU is |
b18c3ca1 | 2194 | * already under consideration through later_mask. |
1baca4ce | 2195 | */ |
b18c3ca1 | 2196 | if (best_cpu < nr_cpu_ids) { |
1baca4ce JL |
2197 | rcu_read_unlock(); |
2198 | return best_cpu; | |
2199 | } | |
2200 | } | |
2201 | } | |
2202 | rcu_read_unlock(); | |
2203 | ||
2204 | /* | |
2205 | * At this point, all our guesses failed, we just return | |
2206 | * 'something', and let the caller sort the things out. | |
2207 | */ | |
2208 | if (this_cpu != -1) | |
2209 | return this_cpu; | |
2210 | ||
14e292f8 | 2211 | cpu = cpumask_any_distribute(later_mask); |
1baca4ce JL |
2212 | if (cpu < nr_cpu_ids) |
2213 | return cpu; | |
2214 | ||
2215 | return -1; | |
2216 | } | |
2217 | ||
2218 | /* Locks the rq it finds */ | |
2219 | static struct rq *find_lock_later_rq(struct task_struct *task, struct rq *rq) | |
2220 | { | |
2221 | struct rq *later_rq = NULL; | |
2222 | int tries; | |
2223 | int cpu; | |
2224 | ||
2225 | for (tries = 0; tries < DL_MAX_TRIES; tries++) { | |
2226 | cpu = find_later_rq(task); | |
2227 | ||
2228 | if ((cpu == -1) || (cpu == rq->cpu)) | |
2229 | break; | |
2230 | ||
2231 | later_rq = cpu_rq(cpu); | |
2232 | ||
973bee49 | 2233 | if (!dl_task_is_earliest_deadline(task, later_rq)) { |
9d514262 WL |
2234 | /* |
2235 | * Target rq has tasks of equal or earlier deadline, | |
2236 | * retrying does not release any lock and is unlikely | |
2237 | * to yield a different result. | |
2238 | */ | |
2239 | later_rq = NULL; | |
2240 | break; | |
2241 | } | |
2242 | ||
1baca4ce JL |
2243 | /* Retry if something changed. */ |
2244 | if (double_lock_balance(rq, later_rq)) { | |
2245 | if (unlikely(task_rq(task) != rq || | |
95158a89 | 2246 | !cpumask_test_cpu(later_rq->cpu, &task->cpus_mask) || |
da0c1e65 | 2247 | task_running(rq, task) || |
13b5ab02 | 2248 | !dl_task(task) || |
da0c1e65 | 2249 | !task_on_rq_queued(task))) { |
1baca4ce JL |
2250 | double_unlock_balance(rq, later_rq); |
2251 | later_rq = NULL; | |
2252 | break; | |
2253 | } | |
2254 | } | |
2255 | ||
2256 | /* | |
2257 | * If the rq we found has no -deadline task, or | |
2258 | * its earliest one has a later deadline than our | |
2259 | * task, the rq is a good one. | |
2260 | */ | |
973bee49 | 2261 | if (dl_task_is_earliest_deadline(task, later_rq)) |
1baca4ce JL |
2262 | break; |
2263 | ||
2264 | /* Otherwise we try again. */ | |
2265 | double_unlock_balance(rq, later_rq); | |
2266 | later_rq = NULL; | |
2267 | } | |
2268 | ||
2269 | return later_rq; | |
2270 | } | |
2271 | ||
2272 | static struct task_struct *pick_next_pushable_dl_task(struct rq *rq) | |
2273 | { | |
2274 | struct task_struct *p; | |
2275 | ||
2276 | if (!has_pushable_dl_tasks(rq)) | |
2277 | return NULL; | |
2278 | ||
f4478e7c | 2279 | p = __node_2_pdl(rb_first_cached(&rq->dl.pushable_dl_tasks_root)); |
1baca4ce | 2280 | |
09348d75 IM |
2281 | WARN_ON_ONCE(rq->cpu != task_cpu(p)); |
2282 | WARN_ON_ONCE(task_current(rq, p)); | |
2283 | WARN_ON_ONCE(p->nr_cpus_allowed <= 1); | |
1baca4ce | 2284 | |
09348d75 IM |
2285 | WARN_ON_ONCE(!task_on_rq_queued(p)); |
2286 | WARN_ON_ONCE(!dl_task(p)); | |
1baca4ce JL |
2287 | |
2288 | return p; | |
2289 | } | |
2290 | ||
2291 | /* | |
2292 | * See if the non running -deadline tasks on this rq | |
2293 | * can be sent to some other CPU where they can preempt | |
2294 | * and start executing. | |
2295 | */ | |
2296 | static int push_dl_task(struct rq *rq) | |
2297 | { | |
2298 | struct task_struct *next_task; | |
2299 | struct rq *later_rq; | |
c51b8ab5 | 2300 | int ret = 0; |
1baca4ce JL |
2301 | |
2302 | if (!rq->dl.overloaded) | |
2303 | return 0; | |
2304 | ||
2305 | next_task = pick_next_pushable_dl_task(rq); | |
2306 | if (!next_task) | |
2307 | return 0; | |
2308 | ||
2309 | retry: | |
1baca4ce JL |
2310 | /* |
2311 | * If next_task preempts rq->curr, and rq->curr | |
2312 | * can move away, it makes sense to just reschedule | |
2313 | * without going further in pushing next_task. | |
2314 | */ | |
2315 | if (dl_task(rq->curr) && | |
2316 | dl_time_before(next_task->dl.deadline, rq->curr->dl.deadline) && | |
4b53a341 | 2317 | rq->curr->nr_cpus_allowed > 1) { |
8875125e | 2318 | resched_curr(rq); |
1baca4ce JL |
2319 | return 0; |
2320 | } | |
2321 | ||
49bef33e VS |
2322 | if (is_migration_disabled(next_task)) |
2323 | return 0; | |
2324 | ||
2325 | if (WARN_ON(next_task == rq->curr)) | |
2326 | return 0; | |
2327 | ||
1baca4ce JL |
2328 | /* We might release rq lock */ |
2329 | get_task_struct(next_task); | |
2330 | ||
2331 | /* Will lock the rq it'll find */ | |
2332 | later_rq = find_lock_later_rq(next_task, rq); | |
2333 | if (!later_rq) { | |
2334 | struct task_struct *task; | |
2335 | ||
2336 | /* | |
2337 | * We must check all this again, since | |
2338 | * find_lock_later_rq releases rq->lock and it is | |
2339 | * then possible that next_task has migrated. | |
2340 | */ | |
2341 | task = pick_next_pushable_dl_task(rq); | |
a776b968 | 2342 | if (task == next_task) { |
1baca4ce JL |
2343 | /* |
2344 | * The task is still there. We don't try | |
97fb7a0a | 2345 | * again, some other CPU will pull it when ready. |
1baca4ce | 2346 | */ |
1baca4ce JL |
2347 | goto out; |
2348 | } | |
2349 | ||
2350 | if (!task) | |
2351 | /* No more tasks */ | |
2352 | goto out; | |
2353 | ||
2354 | put_task_struct(next_task); | |
2355 | next_task = task; | |
2356 | goto retry; | |
2357 | } | |
2358 | ||
2359 | deactivate_task(rq, next_task, 0); | |
2360 | set_task_cpu(next_task, later_rq->cpu); | |
734387ec | 2361 | activate_task(later_rq, next_task, 0); |
c51b8ab5 | 2362 | ret = 1; |
1baca4ce | 2363 | |
8875125e | 2364 | resched_curr(later_rq); |
1baca4ce JL |
2365 | |
2366 | double_unlock_balance(rq, later_rq); | |
2367 | ||
2368 | out: | |
2369 | put_task_struct(next_task); | |
2370 | ||
c51b8ab5 | 2371 | return ret; |
1baca4ce JL |
2372 | } |
2373 | ||
2374 | static void push_dl_tasks(struct rq *rq) | |
2375 | { | |
4ffa08ed | 2376 | /* push_dl_task() will return true if it moved a -deadline task */ |
1baca4ce JL |
2377 | while (push_dl_task(rq)) |
2378 | ; | |
aab03e05 DF |
2379 | } |
2380 | ||
0ea60c20 | 2381 | static void pull_dl_task(struct rq *this_rq) |
1baca4ce | 2382 | { |
0ea60c20 | 2383 | int this_cpu = this_rq->cpu, cpu; |
a7c81556 | 2384 | struct task_struct *p, *push_task; |
0ea60c20 | 2385 | bool resched = false; |
1baca4ce JL |
2386 | struct rq *src_rq; |
2387 | u64 dmin = LONG_MAX; | |
2388 | ||
2389 | if (likely(!dl_overloaded(this_rq))) | |
0ea60c20 | 2390 | return; |
1baca4ce JL |
2391 | |
2392 | /* | |
2393 | * Match the barrier from dl_set_overloaded; this guarantees that if we | |
2394 | * see overloaded we must also see the dlo_mask bit. | |
2395 | */ | |
2396 | smp_rmb(); | |
2397 | ||
2398 | for_each_cpu(cpu, this_rq->rd->dlo_mask) { | |
2399 | if (this_cpu == cpu) | |
2400 | continue; | |
2401 | ||
2402 | src_rq = cpu_rq(cpu); | |
2403 | ||
2404 | /* | |
2405 | * It looks racy, abd it is! However, as in sched_rt.c, | |
2406 | * we are fine with this. | |
2407 | */ | |
2408 | if (this_rq->dl.dl_nr_running && | |
2409 | dl_time_before(this_rq->dl.earliest_dl.curr, | |
2410 | src_rq->dl.earliest_dl.next)) | |
2411 | continue; | |
2412 | ||
2413 | /* Might drop this_rq->lock */ | |
a7c81556 | 2414 | push_task = NULL; |
1baca4ce JL |
2415 | double_lock_balance(this_rq, src_rq); |
2416 | ||
2417 | /* | |
2418 | * If there are no more pullable tasks on the | |
2419 | * rq, we're done with it. | |
2420 | */ | |
2421 | if (src_rq->dl.dl_nr_running <= 1) | |
2422 | goto skip; | |
2423 | ||
8b5e770e | 2424 | p = pick_earliest_pushable_dl_task(src_rq, this_cpu); |
1baca4ce JL |
2425 | |
2426 | /* | |
2427 | * We found a task to be pulled if: | |
2428 | * - it preempts our current (if there's one), | |
2429 | * - it will preempt the last one we pulled (if any). | |
2430 | */ | |
2431 | if (p && dl_time_before(p->dl.deadline, dmin) && | |
973bee49 | 2432 | dl_task_is_earliest_deadline(p, this_rq)) { |
1baca4ce | 2433 | WARN_ON(p == src_rq->curr); |
da0c1e65 | 2434 | WARN_ON(!task_on_rq_queued(p)); |
1baca4ce JL |
2435 | |
2436 | /* | |
2437 | * Then we pull iff p has actually an earlier | |
2438 | * deadline than the current task of its runqueue. | |
2439 | */ | |
2440 | if (dl_time_before(p->dl.deadline, | |
2441 | src_rq->curr->dl.deadline)) | |
2442 | goto skip; | |
2443 | ||
a7c81556 PZ |
2444 | if (is_migration_disabled(p)) { |
2445 | push_task = get_push_task(src_rq); | |
2446 | } else { | |
2447 | deactivate_task(src_rq, p, 0); | |
2448 | set_task_cpu(p, this_cpu); | |
2449 | activate_task(this_rq, p, 0); | |
2450 | dmin = p->dl.deadline; | |
2451 | resched = true; | |
2452 | } | |
1baca4ce JL |
2453 | |
2454 | /* Is there any other task even earlier? */ | |
2455 | } | |
2456 | skip: | |
2457 | double_unlock_balance(this_rq, src_rq); | |
a7c81556 PZ |
2458 | |
2459 | if (push_task) { | |
5cb9eaa3 | 2460 | raw_spin_rq_unlock(this_rq); |
a7c81556 PZ |
2461 | stop_one_cpu_nowait(src_rq->cpu, push_cpu_stop, |
2462 | push_task, &src_rq->push_work); | |
5cb9eaa3 | 2463 | raw_spin_rq_lock(this_rq); |
a7c81556 | 2464 | } |
1baca4ce JL |
2465 | } |
2466 | ||
0ea60c20 PZ |
2467 | if (resched) |
2468 | resched_curr(this_rq); | |
1baca4ce JL |
2469 | } |
2470 | ||
2471 | /* | |
2472 | * Since the task is not running and a reschedule is not going to happen | |
2473 | * anytime soon on its runqueue, we try pushing it away now. | |
2474 | */ | |
2475 | static void task_woken_dl(struct rq *rq, struct task_struct *p) | |
2476 | { | |
2477 | if (!task_running(rq, p) && | |
2478 | !test_tsk_need_resched(rq->curr) && | |
4b53a341 | 2479 | p->nr_cpus_allowed > 1 && |
1baca4ce | 2480 | dl_task(rq->curr) && |
4b53a341 | 2481 | (rq->curr->nr_cpus_allowed < 2 || |
6b0a563f | 2482 | !dl_entity_preempt(&p->dl, &rq->curr->dl))) { |
1baca4ce JL |
2483 | push_dl_tasks(rq); |
2484 | } | |
2485 | } | |
2486 | ||
2487 | static void set_cpus_allowed_dl(struct task_struct *p, | |
9cfc3e18 PZ |
2488 | const struct cpumask *new_mask, |
2489 | u32 flags) | |
1baca4ce | 2490 | { |
7f51412a | 2491 | struct root_domain *src_rd; |
6c37067e | 2492 | struct rq *rq; |
1baca4ce | 2493 | |
09348d75 | 2494 | WARN_ON_ONCE(!dl_task(p)); |
1baca4ce | 2495 | |
7f51412a JL |
2496 | rq = task_rq(p); |
2497 | src_rd = rq->rd; | |
2498 | /* | |
2499 | * Migrating a SCHED_DEADLINE task between exclusive | |
2500 | * cpusets (different root_domains) entails a bandwidth | |
2501 | * update. We already made space for us in the destination | |
2502 | * domain (see cpuset_can_attach()). | |
2503 | */ | |
2504 | if (!cpumask_intersects(src_rd->span, new_mask)) { | |
2505 | struct dl_bw *src_dl_b; | |
2506 | ||
2507 | src_dl_b = dl_bw_of(cpu_of(rq)); | |
2508 | /* | |
2509 | * We now free resources of the root_domain we are migrating | |
2510 | * off. In the worst case, sched_setattr() may temporary fail | |
2511 | * until we complete the update. | |
2512 | */ | |
2513 | raw_spin_lock(&src_dl_b->lock); | |
8c0944ce | 2514 | __dl_sub(src_dl_b, p->dl.dl_bw, dl_bw_cpus(task_cpu(p))); |
7f51412a JL |
2515 | raw_spin_unlock(&src_dl_b->lock); |
2516 | } | |
2517 | ||
9cfc3e18 | 2518 | set_cpus_allowed_common(p, new_mask, flags); |
1baca4ce JL |
2519 | } |
2520 | ||
2521 | /* Assumes rq->lock is held */ | |
2522 | static void rq_online_dl(struct rq *rq) | |
2523 | { | |
2524 | if (rq->dl.overloaded) | |
2525 | dl_set_overload(rq); | |
6bfd6d72 | 2526 | |
16b26943 | 2527 | cpudl_set_freecpu(&rq->rd->cpudl, rq->cpu); |
6bfd6d72 | 2528 | if (rq->dl.dl_nr_running > 0) |
d8206bb3 | 2529 | cpudl_set(&rq->rd->cpudl, rq->cpu, rq->dl.earliest_dl.curr); |
1baca4ce JL |
2530 | } |
2531 | ||
2532 | /* Assumes rq->lock is held */ | |
2533 | static void rq_offline_dl(struct rq *rq) | |
2534 | { | |
2535 | if (rq->dl.overloaded) | |
2536 | dl_clear_overload(rq); | |
6bfd6d72 | 2537 | |
d8206bb3 | 2538 | cpudl_clear(&rq->rd->cpudl, rq->cpu); |
16b26943 | 2539 | cpudl_clear_freecpu(&rq->rd->cpudl, rq->cpu); |
1baca4ce JL |
2540 | } |
2541 | ||
a6c0e746 | 2542 | void __init init_sched_dl_class(void) |
1baca4ce JL |
2543 | { |
2544 | unsigned int i; | |
2545 | ||
2546 | for_each_possible_cpu(i) | |
2547 | zalloc_cpumask_var_node(&per_cpu(local_cpu_mask_dl, i), | |
2548 | GFP_KERNEL, cpu_to_node(i)); | |
2549 | } | |
2550 | ||
f9a25f77 MP |
2551 | void dl_add_task_root_domain(struct task_struct *p) |
2552 | { | |
2553 | struct rq_flags rf; | |
2554 | struct rq *rq; | |
2555 | struct dl_bw *dl_b; | |
2556 | ||
de40f33e DE |
2557 | raw_spin_lock_irqsave(&p->pi_lock, rf.flags); |
2558 | if (!dl_task(p)) { | |
2559 | raw_spin_unlock_irqrestore(&p->pi_lock, rf.flags); | |
2560 | return; | |
2561 | } | |
2562 | ||
2563 | rq = __task_rq_lock(p, &rf); | |
f9a25f77 MP |
2564 | |
2565 | dl_b = &rq->rd->dl_bw; | |
2566 | raw_spin_lock(&dl_b->lock); | |
2567 | ||
2568 | __dl_add(dl_b, p->dl.dl_bw, cpumask_weight(rq->rd->span)); | |
2569 | ||
2570 | raw_spin_unlock(&dl_b->lock); | |
2571 | ||
f9a25f77 MP |
2572 | task_rq_unlock(rq, p, &rf); |
2573 | } | |
2574 | ||
2575 | void dl_clear_root_domain(struct root_domain *rd) | |
2576 | { | |
2577 | unsigned long flags; | |
2578 | ||
2579 | raw_spin_lock_irqsave(&rd->dl_bw.lock, flags); | |
2580 | rd->dl_bw.total_bw = 0; | |
2581 | raw_spin_unlock_irqrestore(&rd->dl_bw.lock, flags); | |
2582 | } | |
2583 | ||
1baca4ce JL |
2584 | #endif /* CONFIG_SMP */ |
2585 | ||
aab03e05 DF |
2586 | static void switched_from_dl(struct rq *rq, struct task_struct *p) |
2587 | { | |
a649f237 | 2588 | /* |
209a0cbd LA |
2589 | * task_non_contending() can start the "inactive timer" (if the 0-lag |
2590 | * time is in the future). If the task switches back to dl before | |
2591 | * the "inactive timer" fires, it can continue to consume its current | |
2592 | * runtime using its current deadline. If it stays outside of | |
2593 | * SCHED_DEADLINE until the 0-lag time passes, inactive_task_timer() | |
2594 | * will reset the task parameters. | |
a649f237 | 2595 | */ |
209a0cbd LA |
2596 | if (task_on_rq_queued(p) && p->dl.dl_runtime) |
2597 | task_non_contending(p); | |
2598 | ||
e117cb52 JL |
2599 | if (!task_on_rq_queued(p)) { |
2600 | /* | |
2601 | * Inactive timer is armed. However, p is leaving DEADLINE and | |
2602 | * might migrate away from this rq while continuing to run on | |
2603 | * some other class. We need to remove its contribution from | |
2604 | * this rq running_bw now, or sub_rq_bw (below) will complain. | |
2605 | */ | |
2606 | if (p->dl.dl_non_contending) | |
2607 | sub_running_bw(&p->dl, &rq->dl); | |
794a56eb | 2608 | sub_rq_bw(&p->dl, &rq->dl); |
e117cb52 | 2609 | } |
8fd27231 | 2610 | |
209a0cbd LA |
2611 | /* |
2612 | * We cannot use inactive_task_timer() to invoke sub_running_bw() | |
2613 | * at the 0-lag time, because the task could have been migrated | |
2614 | * while SCHED_OTHER in the meanwhile. | |
2615 | */ | |
2616 | if (p->dl.dl_non_contending) | |
2617 | p->dl.dl_non_contending = 0; | |
a5e7be3b | 2618 | |
1baca4ce JL |
2619 | /* |
2620 | * Since this might be the only -deadline task on the rq, | |
2621 | * this is the right place to try to pull some other one | |
97fb7a0a | 2622 | * from an overloaded CPU, if any. |
1baca4ce | 2623 | */ |
cd660911 WL |
2624 | if (!task_on_rq_queued(p) || rq->dl.dl_nr_running) |
2625 | return; | |
2626 | ||
02d8ec94 | 2627 | deadline_queue_pull_task(rq); |
aab03e05 DF |
2628 | } |
2629 | ||
1baca4ce JL |
2630 | /* |
2631 | * When switching to -deadline, we may overload the rq, then | |
2632 | * we try to push someone off, if possible. | |
2633 | */ | |
aab03e05 DF |
2634 | static void switched_to_dl(struct rq *rq, struct task_struct *p) |
2635 | { | |
209a0cbd LA |
2636 | if (hrtimer_try_to_cancel(&p->dl.inactive_timer) == 1) |
2637 | put_task_struct(p); | |
98b0a857 JL |
2638 | |
2639 | /* If p is not queued we will update its parameters at next wakeup. */ | |
8fd27231 | 2640 | if (!task_on_rq_queued(p)) { |
794a56eb | 2641 | add_rq_bw(&p->dl, &rq->dl); |
98b0a857 | 2642 | |
8fd27231 LA |
2643 | return; |
2644 | } | |
72f9f3fd | 2645 | |
98b0a857 | 2646 | if (rq->curr != p) { |
1baca4ce | 2647 | #ifdef CONFIG_SMP |
4b53a341 | 2648 | if (p->nr_cpus_allowed > 1 && rq->dl.overloaded) |
02d8ec94 | 2649 | deadline_queue_push_tasks(rq); |
619bd4a7 | 2650 | #endif |
9916e214 PZ |
2651 | if (dl_task(rq->curr)) |
2652 | check_preempt_curr_dl(rq, p, 0); | |
2653 | else | |
2654 | resched_curr(rq); | |
d7d60709 VD |
2655 | } else { |
2656 | update_dl_rq_load_avg(rq_clock_pelt(rq), rq, 0); | |
aab03e05 DF |
2657 | } |
2658 | } | |
2659 | ||
1baca4ce JL |
2660 | /* |
2661 | * If the scheduling parameters of a -deadline task changed, | |
2662 | * a push or pull operation might be needed. | |
2663 | */ | |
aab03e05 DF |
2664 | static void prio_changed_dl(struct rq *rq, struct task_struct *p, |
2665 | int oldprio) | |
2666 | { | |
65bcf072 | 2667 | if (task_on_rq_queued(p) || task_current(rq, p)) { |
aab03e05 | 2668 | #ifdef CONFIG_SMP |
1baca4ce JL |
2669 | /* |
2670 | * This might be too much, but unfortunately | |
2671 | * we don't have the old deadline value, and | |
2672 | * we can't argue if the task is increasing | |
2673 | * or lowering its prio, so... | |
2674 | */ | |
2675 | if (!rq->dl.overloaded) | |
02d8ec94 | 2676 | deadline_queue_pull_task(rq); |
1baca4ce JL |
2677 | |
2678 | /* | |
2679 | * If we now have a earlier deadline task than p, | |
2680 | * then reschedule, provided p is still on this | |
2681 | * runqueue. | |
2682 | */ | |
9916e214 | 2683 | if (dl_time_before(rq->dl.earliest_dl.curr, p->dl.deadline)) |
8875125e | 2684 | resched_curr(rq); |
1baca4ce JL |
2685 | #else |
2686 | /* | |
2687 | * Again, we don't know if p has a earlier | |
2688 | * or later deadline, so let's blindly set a | |
2689 | * (maybe not needed) rescheduling point. | |
2690 | */ | |
8875125e | 2691 | resched_curr(rq); |
1baca4ce | 2692 | #endif /* CONFIG_SMP */ |
801ccdbf | 2693 | } |
aab03e05 | 2694 | } |
aab03e05 | 2695 | |
43c31ac0 PZ |
2696 | DEFINE_SCHED_CLASS(dl) = { |
2697 | ||
aab03e05 DF |
2698 | .enqueue_task = enqueue_task_dl, |
2699 | .dequeue_task = dequeue_task_dl, | |
2700 | .yield_task = yield_task_dl, | |
2701 | ||
2702 | .check_preempt_curr = check_preempt_curr_dl, | |
2703 | ||
2704 | .pick_next_task = pick_next_task_dl, | |
2705 | .put_prev_task = put_prev_task_dl, | |
03b7fad1 | 2706 | .set_next_task = set_next_task_dl, |
aab03e05 DF |
2707 | |
2708 | #ifdef CONFIG_SMP | |
6e2df058 | 2709 | .balance = balance_dl, |
21f56ffe | 2710 | .pick_task = pick_task_dl, |
aab03e05 | 2711 | .select_task_rq = select_task_rq_dl, |
209a0cbd | 2712 | .migrate_task_rq = migrate_task_rq_dl, |
1baca4ce JL |
2713 | .set_cpus_allowed = set_cpus_allowed_dl, |
2714 | .rq_online = rq_online_dl, | |
2715 | .rq_offline = rq_offline_dl, | |
1baca4ce | 2716 | .task_woken = task_woken_dl, |
a7c81556 | 2717 | .find_lock_rq = find_lock_later_rq, |
aab03e05 DF |
2718 | #endif |
2719 | ||
aab03e05 DF |
2720 | .task_tick = task_tick_dl, |
2721 | .task_fork = task_fork_dl, | |
aab03e05 DF |
2722 | |
2723 | .prio_changed = prio_changed_dl, | |
2724 | .switched_from = switched_from_dl, | |
2725 | .switched_to = switched_to_dl, | |
6e998916 SG |
2726 | |
2727 | .update_curr = update_curr_dl, | |
aab03e05 | 2728 | }; |
acb32132 | 2729 | |
26762423 PL |
2730 | /* Used for dl_bw check and update, used under sched_rt_handler()::mutex */ |
2731 | static u64 dl_generation; | |
2732 | ||
06a76fe0 NP |
2733 | int sched_dl_global_validate(void) |
2734 | { | |
2735 | u64 runtime = global_rt_runtime(); | |
2736 | u64 period = global_rt_period(); | |
2737 | u64 new_bw = to_ratio(period, runtime); | |
26762423 | 2738 | u64 gen = ++dl_generation; |
06a76fe0 | 2739 | struct dl_bw *dl_b; |
a57415f5 | 2740 | int cpu, cpus, ret = 0; |
06a76fe0 NP |
2741 | unsigned long flags; |
2742 | ||
2743 | /* | |
2744 | * Here we want to check the bandwidth not being set to some | |
2745 | * value smaller than the currently allocated bandwidth in | |
2746 | * any of the root_domains. | |
06a76fe0 NP |
2747 | */ |
2748 | for_each_possible_cpu(cpu) { | |
2749 | rcu_read_lock_sched(); | |
26762423 PL |
2750 | |
2751 | if (dl_bw_visited(cpu, gen)) | |
2752 | goto next; | |
2753 | ||
06a76fe0 | 2754 | dl_b = dl_bw_of(cpu); |
a57415f5 | 2755 | cpus = dl_bw_cpus(cpu); |
06a76fe0 NP |
2756 | |
2757 | raw_spin_lock_irqsave(&dl_b->lock, flags); | |
a57415f5 | 2758 | if (new_bw * cpus < dl_b->total_bw) |
06a76fe0 NP |
2759 | ret = -EBUSY; |
2760 | raw_spin_unlock_irqrestore(&dl_b->lock, flags); | |
2761 | ||
26762423 | 2762 | next: |
06a76fe0 NP |
2763 | rcu_read_unlock_sched(); |
2764 | ||
2765 | if (ret) | |
2766 | break; | |
2767 | } | |
2768 | ||
2769 | return ret; | |
2770 | } | |
2771 | ||
ba4f7bc1 | 2772 | static void init_dl_rq_bw_ratio(struct dl_rq *dl_rq) |
06a76fe0 NP |
2773 | { |
2774 | if (global_rt_runtime() == RUNTIME_INF) { | |
2775 | dl_rq->bw_ratio = 1 << RATIO_SHIFT; | |
2776 | dl_rq->extra_bw = 1 << BW_SHIFT; | |
2777 | } else { | |
2778 | dl_rq->bw_ratio = to_ratio(global_rt_runtime(), | |
2779 | global_rt_period()) >> (BW_SHIFT - RATIO_SHIFT); | |
2780 | dl_rq->extra_bw = to_ratio(global_rt_period(), | |
2781 | global_rt_runtime()); | |
2782 | } | |
2783 | } | |
2784 | ||
2785 | void sched_dl_do_global(void) | |
2786 | { | |
2787 | u64 new_bw = -1; | |
26762423 | 2788 | u64 gen = ++dl_generation; |
06a76fe0 NP |
2789 | struct dl_bw *dl_b; |
2790 | int cpu; | |
2791 | unsigned long flags; | |
2792 | ||
06a76fe0 NP |
2793 | if (global_rt_runtime() != RUNTIME_INF) |
2794 | new_bw = to_ratio(global_rt_period(), global_rt_runtime()); | |
2795 | ||
06a76fe0 NP |
2796 | for_each_possible_cpu(cpu) { |
2797 | rcu_read_lock_sched(); | |
26762423 PL |
2798 | |
2799 | if (dl_bw_visited(cpu, gen)) { | |
2800 | rcu_read_unlock_sched(); | |
2801 | continue; | |
2802 | } | |
2803 | ||
06a76fe0 NP |
2804 | dl_b = dl_bw_of(cpu); |
2805 | ||
2806 | raw_spin_lock_irqsave(&dl_b->lock, flags); | |
2807 | dl_b->bw = new_bw; | |
2808 | raw_spin_unlock_irqrestore(&dl_b->lock, flags); | |
2809 | ||
2810 | rcu_read_unlock_sched(); | |
2811 | init_dl_rq_bw_ratio(&cpu_rq(cpu)->dl); | |
2812 | } | |
2813 | } | |
2814 | ||
2815 | /* | |
2816 | * We must be sure that accepting a new task (or allowing changing the | |
2817 | * parameters of an existing one) is consistent with the bandwidth | |
2818 | * constraints. If yes, this function also accordingly updates the currently | |
2819 | * allocated bandwidth to reflect the new situation. | |
2820 | * | |
2821 | * This function is called while holding p's rq->lock. | |
2822 | */ | |
2823 | int sched_dl_overflow(struct task_struct *p, int policy, | |
2824 | const struct sched_attr *attr) | |
2825 | { | |
06a76fe0 NP |
2826 | u64 period = attr->sched_period ?: attr->sched_deadline; |
2827 | u64 runtime = attr->sched_runtime; | |
2828 | u64 new_bw = dl_policy(policy) ? to_ratio(period, runtime) : 0; | |
60ffd5ed LA |
2829 | int cpus, err = -1, cpu = task_cpu(p); |
2830 | struct dl_bw *dl_b = dl_bw_of(cpu); | |
2831 | unsigned long cap; | |
06a76fe0 | 2832 | |
794a56eb JL |
2833 | if (attr->sched_flags & SCHED_FLAG_SUGOV) |
2834 | return 0; | |
2835 | ||
06a76fe0 NP |
2836 | /* !deadline task may carry old deadline bandwidth */ |
2837 | if (new_bw == p->dl.dl_bw && task_has_dl_policy(p)) | |
2838 | return 0; | |
2839 | ||
2840 | /* | |
2841 | * Either if a task, enters, leave, or stays -deadline but changes | |
2842 | * its parameters, we may need to update accordingly the total | |
2843 | * allocated bandwidth of the container. | |
2844 | */ | |
2845 | raw_spin_lock(&dl_b->lock); | |
60ffd5ed LA |
2846 | cpus = dl_bw_cpus(cpu); |
2847 | cap = dl_bw_capacity(cpu); | |
2848 | ||
06a76fe0 | 2849 | if (dl_policy(policy) && !task_has_dl_policy(p) && |
60ffd5ed | 2850 | !__dl_overflow(dl_b, cap, 0, new_bw)) { |
06a76fe0 | 2851 | if (hrtimer_active(&p->dl.inactive_timer)) |
8c0944ce | 2852 | __dl_sub(dl_b, p->dl.dl_bw, cpus); |
06a76fe0 NP |
2853 | __dl_add(dl_b, new_bw, cpus); |
2854 | err = 0; | |
2855 | } else if (dl_policy(policy) && task_has_dl_policy(p) && | |
60ffd5ed | 2856 | !__dl_overflow(dl_b, cap, p->dl.dl_bw, new_bw)) { |
06a76fe0 NP |
2857 | /* |
2858 | * XXX this is slightly incorrect: when the task | |
2859 | * utilization decreases, we should delay the total | |
2860 | * utilization change until the task's 0-lag point. | |
2861 | * But this would require to set the task's "inactive | |
2862 | * timer" when the task is not inactive. | |
2863 | */ | |
8c0944ce | 2864 | __dl_sub(dl_b, p->dl.dl_bw, cpus); |
06a76fe0 NP |
2865 | __dl_add(dl_b, new_bw, cpus); |
2866 | dl_change_utilization(p, new_bw); | |
2867 | err = 0; | |
2868 | } else if (!dl_policy(policy) && task_has_dl_policy(p)) { | |
2869 | /* | |
2870 | * Do not decrease the total deadline utilization here, | |
2871 | * switched_from_dl() will take care to do it at the correct | |
2872 | * (0-lag) time. | |
2873 | */ | |
2874 | err = 0; | |
2875 | } | |
2876 | raw_spin_unlock(&dl_b->lock); | |
2877 | ||
2878 | return err; | |
2879 | } | |
2880 | ||
2881 | /* | |
2882 | * This function initializes the sched_dl_entity of a newly becoming | |
2883 | * SCHED_DEADLINE task. | |
2884 | * | |
2885 | * Only the static values are considered here, the actual runtime and the | |
2886 | * absolute deadline will be properly calculated when the task is enqueued | |
2887 | * for the first time with its new policy. | |
2888 | */ | |
2889 | void __setparam_dl(struct task_struct *p, const struct sched_attr *attr) | |
2890 | { | |
2891 | struct sched_dl_entity *dl_se = &p->dl; | |
2892 | ||
2893 | dl_se->dl_runtime = attr->sched_runtime; | |
2894 | dl_se->dl_deadline = attr->sched_deadline; | |
2895 | dl_se->dl_period = attr->sched_period ?: dl_se->dl_deadline; | |
f9509153 | 2896 | dl_se->flags = attr->sched_flags & SCHED_DL_FLAGS; |
06a76fe0 NP |
2897 | dl_se->dl_bw = to_ratio(dl_se->dl_period, dl_se->dl_runtime); |
2898 | dl_se->dl_density = to_ratio(dl_se->dl_deadline, dl_se->dl_runtime); | |
2899 | } | |
2900 | ||
2901 | void __getparam_dl(struct task_struct *p, struct sched_attr *attr) | |
2902 | { | |
2903 | struct sched_dl_entity *dl_se = &p->dl; | |
2904 | ||
2905 | attr->sched_priority = p->rt_priority; | |
2906 | attr->sched_runtime = dl_se->dl_runtime; | |
2907 | attr->sched_deadline = dl_se->dl_deadline; | |
2908 | attr->sched_period = dl_se->dl_period; | |
f9509153 QP |
2909 | attr->sched_flags &= ~SCHED_DL_FLAGS; |
2910 | attr->sched_flags |= dl_se->flags; | |
06a76fe0 NP |
2911 | } |
2912 | ||
2913 | /* | |
2914 | * This function validates the new parameters of a -deadline task. | |
2915 | * We ask for the deadline not being zero, and greater or equal | |
2916 | * than the runtime, as well as the period of being zero or | |
2917 | * greater than deadline. Furthermore, we have to be sure that | |
2918 | * user parameters are above the internal resolution of 1us (we | |
2919 | * check sched_runtime only since it is always the smaller one) and | |
2920 | * below 2^63 ns (we have to check both sched_deadline and | |
2921 | * sched_period, as the latter can be zero). | |
2922 | */ | |
2923 | bool __checkparam_dl(const struct sched_attr *attr) | |
2924 | { | |
b4098bfc PZ |
2925 | u64 period, max, min; |
2926 | ||
794a56eb JL |
2927 | /* special dl tasks don't actually use any parameter */ |
2928 | if (attr->sched_flags & SCHED_FLAG_SUGOV) | |
2929 | return true; | |
2930 | ||
06a76fe0 NP |
2931 | /* deadline != 0 */ |
2932 | if (attr->sched_deadline == 0) | |
2933 | return false; | |
2934 | ||
2935 | /* | |
2936 | * Since we truncate DL_SCALE bits, make sure we're at least | |
2937 | * that big. | |
2938 | */ | |
2939 | if (attr->sched_runtime < (1ULL << DL_SCALE)) | |
2940 | return false; | |
2941 | ||
2942 | /* | |
2943 | * Since we use the MSB for wrap-around and sign issues, make | |
2944 | * sure it's not set (mind that period can be equal to zero). | |
2945 | */ | |
2946 | if (attr->sched_deadline & (1ULL << 63) || | |
2947 | attr->sched_period & (1ULL << 63)) | |
2948 | return false; | |
2949 | ||
b4098bfc PZ |
2950 | period = attr->sched_period; |
2951 | if (!period) | |
2952 | period = attr->sched_deadline; | |
2953 | ||
06a76fe0 | 2954 | /* runtime <= deadline <= period (if period != 0) */ |
b4098bfc | 2955 | if (period < attr->sched_deadline || |
06a76fe0 NP |
2956 | attr->sched_deadline < attr->sched_runtime) |
2957 | return false; | |
2958 | ||
b4098bfc PZ |
2959 | max = (u64)READ_ONCE(sysctl_sched_dl_period_max) * NSEC_PER_USEC; |
2960 | min = (u64)READ_ONCE(sysctl_sched_dl_period_min) * NSEC_PER_USEC; | |
2961 | ||
2962 | if (period < min || period > max) | |
2963 | return false; | |
2964 | ||
06a76fe0 NP |
2965 | return true; |
2966 | } | |
2967 | ||
2968 | /* | |
2969 | * This function clears the sched_dl_entity static params. | |
2970 | */ | |
2971 | void __dl_clear_params(struct task_struct *p) | |
2972 | { | |
2973 | struct sched_dl_entity *dl_se = &p->dl; | |
2974 | ||
97fb7a0a IM |
2975 | dl_se->dl_runtime = 0; |
2976 | dl_se->dl_deadline = 0; | |
2977 | dl_se->dl_period = 0; | |
2978 | dl_se->flags = 0; | |
2979 | dl_se->dl_bw = 0; | |
2980 | dl_se->dl_density = 0; | |
06a76fe0 | 2981 | |
97fb7a0a IM |
2982 | dl_se->dl_throttled = 0; |
2983 | dl_se->dl_yielded = 0; | |
2984 | dl_se->dl_non_contending = 0; | |
2985 | dl_se->dl_overrun = 0; | |
2279f540 JL |
2986 | |
2987 | #ifdef CONFIG_RT_MUTEXES | |
2988 | dl_se->pi_se = dl_se; | |
2989 | #endif | |
06a76fe0 NP |
2990 | } |
2991 | ||
2992 | bool dl_param_changed(struct task_struct *p, const struct sched_attr *attr) | |
2993 | { | |
2994 | struct sched_dl_entity *dl_se = &p->dl; | |
2995 | ||
2996 | if (dl_se->dl_runtime != attr->sched_runtime || | |
2997 | dl_se->dl_deadline != attr->sched_deadline || | |
2998 | dl_se->dl_period != attr->sched_period || | |
f9509153 | 2999 | dl_se->flags != (attr->sched_flags & SCHED_DL_FLAGS)) |
06a76fe0 NP |
3000 | return true; |
3001 | ||
3002 | return false; | |
3003 | } | |
3004 | ||
3005 | #ifdef CONFIG_SMP | |
06a76fe0 NP |
3006 | int dl_cpuset_cpumask_can_shrink(const struct cpumask *cur, |
3007 | const struct cpumask *trial) | |
3008 | { | |
6092478b | 3009 | unsigned long flags, cap; |
06a76fe0 | 3010 | struct dl_bw *cur_dl_b; |
6092478b | 3011 | int ret = 1; |
06a76fe0 NP |
3012 | |
3013 | rcu_read_lock_sched(); | |
3014 | cur_dl_b = dl_bw_of(cpumask_any(cur)); | |
6092478b | 3015 | cap = __dl_bw_capacity(trial); |
06a76fe0 | 3016 | raw_spin_lock_irqsave(&cur_dl_b->lock, flags); |
6092478b | 3017 | if (__dl_overflow(cur_dl_b, cap, 0, 0)) |
06a76fe0 NP |
3018 | ret = 0; |
3019 | raw_spin_unlock_irqrestore(&cur_dl_b->lock, flags); | |
3020 | rcu_read_unlock_sched(); | |
97fb7a0a | 3021 | |
06a76fe0 NP |
3022 | return ret; |
3023 | } | |
3024 | ||
772b6539 | 3025 | int dl_cpu_busy(int cpu, struct task_struct *p) |
06a76fe0 | 3026 | { |
60ffd5ed | 3027 | unsigned long flags, cap; |
06a76fe0 NP |
3028 | struct dl_bw *dl_b; |
3029 | bool overflow; | |
06a76fe0 NP |
3030 | |
3031 | rcu_read_lock_sched(); | |
3032 | dl_b = dl_bw_of(cpu); | |
3033 | raw_spin_lock_irqsave(&dl_b->lock, flags); | |
60ffd5ed | 3034 | cap = dl_bw_capacity(cpu); |
772b6539 DE |
3035 | overflow = __dl_overflow(dl_b, cap, 0, p ? p->dl.dl_bw : 0); |
3036 | ||
3037 | if (!overflow && p) { | |
3038 | /* | |
3039 | * We reserve space for this task in the destination | |
3040 | * root_domain, as we can't fail after this point. | |
3041 | * We will free resources in the source root_domain | |
3042 | * later on (see set_cpus_allowed_dl()). | |
3043 | */ | |
3044 | __dl_add(dl_b, p->dl.dl_bw, dl_bw_cpus(cpu)); | |
3045 | } | |
3046 | ||
06a76fe0 NP |
3047 | raw_spin_unlock_irqrestore(&dl_b->lock, flags); |
3048 | rcu_read_unlock_sched(); | |
97fb7a0a | 3049 | |
772b6539 | 3050 | return overflow ? -EBUSY : 0; |
06a76fe0 NP |
3051 | } |
3052 | #endif | |
3053 | ||
acb32132 | 3054 | #ifdef CONFIG_SCHED_DEBUG |
acb32132 WL |
3055 | void print_dl_stats(struct seq_file *m, int cpu) |
3056 | { | |
3057 | print_dl_rq(m, cpu, &cpu_rq(cpu)->dl); | |
3058 | } | |
3059 | #endif /* CONFIG_SCHED_DEBUG */ |