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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 | |
6c24849f JL |
19 | #include <linux/cpuset.h> |
20 | ||
84227c12 ZN |
21 | /* |
22 | * Default limits for DL period; on the top end we guard against small util | |
23 | * tasks still getting ridiculously long effective runtimes, on the bottom end we | |
24 | * guard against timer DoS. | |
25 | */ | |
26 | static unsigned int sysctl_sched_dl_period_max = 1 << 22; /* ~4 seconds */ | |
27 | static unsigned int sysctl_sched_dl_period_min = 100; /* 100 us */ | |
28 | #ifdef CONFIG_SYSCTL | |
29 | static struct ctl_table sched_dl_sysctls[] = { | |
30 | { | |
31 | .procname = "sched_deadline_period_max_us", | |
32 | .data = &sysctl_sched_dl_period_max, | |
33 | .maxlen = sizeof(unsigned int), | |
34 | .mode = 0644, | |
2ed81e76 YD |
35 | .proc_handler = proc_douintvec_minmax, |
36 | .extra1 = (void *)&sysctl_sched_dl_period_min, | |
84227c12 ZN |
37 | }, |
38 | { | |
39 | .procname = "sched_deadline_period_min_us", | |
40 | .data = &sysctl_sched_dl_period_min, | |
41 | .maxlen = sizeof(unsigned int), | |
42 | .mode = 0644, | |
2ed81e76 YD |
43 | .proc_handler = proc_douintvec_minmax, |
44 | .extra2 = (void *)&sysctl_sched_dl_period_max, | |
84227c12 ZN |
45 | }, |
46 | {} | |
47 | }; | |
48 | ||
49 | static int __init sched_dl_sysctl_init(void) | |
50 | { | |
51 | register_sysctl_init("kernel", sched_dl_sysctls); | |
52 | return 0; | |
53 | } | |
54 | late_initcall(sched_dl_sysctl_init); | |
55 | #endif | |
56 | ||
aab03e05 DF |
57 | static inline struct task_struct *dl_task_of(struct sched_dl_entity *dl_se) |
58 | { | |
59 | return container_of(dl_se, struct task_struct, dl); | |
60 | } | |
61 | ||
62 | static inline struct rq *rq_of_dl_rq(struct dl_rq *dl_rq) | |
63 | { | |
64 | return container_of(dl_rq, struct rq, dl); | |
65 | } | |
66 | ||
67 | static inline struct dl_rq *dl_rq_of_se(struct sched_dl_entity *dl_se) | |
68 | { | |
69 | struct task_struct *p = dl_task_of(dl_se); | |
70 | struct rq *rq = task_rq(p); | |
71 | ||
72 | return &rq->dl; | |
73 | } | |
74 | ||
75 | static inline int on_dl_rq(struct sched_dl_entity *dl_se) | |
76 | { | |
77 | return !RB_EMPTY_NODE(&dl_se->rb_node); | |
78 | } | |
79 | ||
2279f540 JL |
80 | #ifdef CONFIG_RT_MUTEXES |
81 | static inline struct sched_dl_entity *pi_of(struct sched_dl_entity *dl_se) | |
82 | { | |
83 | return dl_se->pi_se; | |
84 | } | |
85 | ||
86 | static inline bool is_dl_boosted(struct sched_dl_entity *dl_se) | |
87 | { | |
88 | return pi_of(dl_se) != dl_se; | |
89 | } | |
90 | #else | |
91 | static inline struct sched_dl_entity *pi_of(struct sched_dl_entity *dl_se) | |
92 | { | |
93 | return dl_se; | |
94 | } | |
95 | ||
96 | static inline bool is_dl_boosted(struct sched_dl_entity *dl_se) | |
97 | { | |
98 | return false; | |
99 | } | |
100 | #endif | |
101 | ||
06a76fe0 NP |
102 | #ifdef CONFIG_SMP |
103 | static inline struct dl_bw *dl_bw_of(int i) | |
104 | { | |
105 | RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held(), | |
106 | "sched RCU must be held"); | |
107 | return &cpu_rq(i)->rd->dl_bw; | |
108 | } | |
109 | ||
110 | static inline int dl_bw_cpus(int i) | |
111 | { | |
112 | struct root_domain *rd = cpu_rq(i)->rd; | |
c81b8932 | 113 | int cpus; |
06a76fe0 NP |
114 | |
115 | RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held(), | |
116 | "sched RCU must be held"); | |
c81b8932 DE |
117 | |
118 | if (cpumask_subset(rd->span, cpu_active_mask)) | |
119 | return cpumask_weight(rd->span); | |
120 | ||
121 | cpus = 0; | |
122 | ||
06a76fe0 NP |
123 | for_each_cpu_and(i, rd->span, cpu_active_mask) |
124 | cpus++; | |
125 | ||
126 | return cpus; | |
127 | } | |
fc9dc698 | 128 | |
6092478b | 129 | static inline unsigned long __dl_bw_capacity(const struct cpumask *mask) |
fc9dc698 | 130 | { |
fc9dc698 | 131 | unsigned long cap = 0; |
6092478b | 132 | int i; |
fc9dc698 | 133 | |
6092478b | 134 | for_each_cpu_and(i, mask, cpu_active_mask) |
7bc26384 | 135 | cap += arch_scale_cpu_capacity(i); |
fc9dc698 DE |
136 | |
137 | return cap; | |
138 | } | |
139 | ||
140 | /* | |
141 | * XXX Fix: If 'rq->rd == def_root_domain' perform AC against capacity | |
142 | * of the CPU the task is running on rather rd's \Sum CPU capacity. | |
143 | */ | |
144 | static inline unsigned long dl_bw_capacity(int i) | |
145 | { | |
740cf8a7 | 146 | if (!sched_asym_cpucap_active() && |
7bc26384 | 147 | arch_scale_cpu_capacity(i) == SCHED_CAPACITY_SCALE) { |
fc9dc698 DE |
148 | return dl_bw_cpus(i) << SCHED_CAPACITY_SHIFT; |
149 | } else { | |
6092478b DE |
150 | RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held(), |
151 | "sched RCU must be held"); | |
152 | ||
153 | return __dl_bw_capacity(cpu_rq(i)->rd->span); | |
fc9dc698 DE |
154 | } |
155 | } | |
26762423 PL |
156 | |
157 | static inline bool dl_bw_visited(int cpu, u64 gen) | |
158 | { | |
159 | struct root_domain *rd = cpu_rq(cpu)->rd; | |
160 | ||
161 | if (rd->visit_gen == gen) | |
162 | return true; | |
163 | ||
164 | rd->visit_gen = gen; | |
165 | return false; | |
166 | } | |
f1304ecb DE |
167 | |
168 | static inline | |
169 | void __dl_update(struct dl_bw *dl_b, s64 bw) | |
170 | { | |
171 | struct root_domain *rd = container_of(dl_b, struct root_domain, dl_bw); | |
172 | int i; | |
173 | ||
174 | RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held(), | |
175 | "sched RCU must be held"); | |
176 | for_each_cpu_and(i, rd->span, cpu_active_mask) { | |
177 | struct rq *rq = cpu_rq(i); | |
178 | ||
179 | rq->dl.extra_bw += bw; | |
180 | } | |
181 | } | |
06a76fe0 NP |
182 | #else |
183 | static inline struct dl_bw *dl_bw_of(int i) | |
184 | { | |
185 | return &cpu_rq(i)->dl.dl_bw; | |
186 | } | |
187 | ||
188 | static inline int dl_bw_cpus(int i) | |
189 | { | |
190 | return 1; | |
191 | } | |
fc9dc698 DE |
192 | |
193 | static inline unsigned long dl_bw_capacity(int i) | |
194 | { | |
195 | return SCHED_CAPACITY_SCALE; | |
196 | } | |
26762423 PL |
197 | |
198 | static inline bool dl_bw_visited(int cpu, u64 gen) | |
199 | { | |
200 | return false; | |
201 | } | |
f1304ecb DE |
202 | |
203 | static inline | |
204 | void __dl_update(struct dl_bw *dl_b, s64 bw) | |
205 | { | |
206 | struct dl_rq *dl = container_of(dl_b, struct dl_rq, dl_bw); | |
207 | ||
208 | dl->extra_bw += bw; | |
209 | } | |
06a76fe0 NP |
210 | #endif |
211 | ||
f1304ecb DE |
212 | static inline |
213 | void __dl_sub(struct dl_bw *dl_b, u64 tsk_bw, int cpus) | |
214 | { | |
215 | dl_b->total_bw -= tsk_bw; | |
216 | __dl_update(dl_b, (s32)tsk_bw / cpus); | |
217 | } | |
218 | ||
219 | static inline | |
220 | void __dl_add(struct dl_bw *dl_b, u64 tsk_bw, int cpus) | |
221 | { | |
222 | dl_b->total_bw += tsk_bw; | |
223 | __dl_update(dl_b, -((s32)tsk_bw / cpus)); | |
224 | } | |
225 | ||
226 | static inline bool | |
227 | __dl_overflow(struct dl_bw *dl_b, unsigned long cap, u64 old_bw, u64 new_bw) | |
228 | { | |
229 | return dl_b->bw != -1 && | |
230 | cap_scale(dl_b->bw, cap) < dl_b->total_bw - old_bw + new_bw; | |
231 | } | |
232 | ||
e36d8677 | 233 | static inline |
794a56eb | 234 | void __add_running_bw(u64 dl_bw, struct dl_rq *dl_rq) |
e36d8677 LA |
235 | { |
236 | u64 old = dl_rq->running_bw; | |
237 | ||
5cb9eaa3 | 238 | lockdep_assert_rq_held(rq_of_dl_rq(dl_rq)); |
e36d8677 LA |
239 | dl_rq->running_bw += dl_bw; |
240 | SCHED_WARN_ON(dl_rq->running_bw < old); /* overflow */ | |
8fd27231 | 241 | SCHED_WARN_ON(dl_rq->running_bw > dl_rq->this_bw); |
e0367b12 | 242 | /* kick cpufreq (see the comment in kernel/sched/sched.h). */ |
4042d003 | 243 | cpufreq_update_util(rq_of_dl_rq(dl_rq), 0); |
e36d8677 LA |
244 | } |
245 | ||
246 | static inline | |
794a56eb | 247 | void __sub_running_bw(u64 dl_bw, struct dl_rq *dl_rq) |
e36d8677 LA |
248 | { |
249 | u64 old = dl_rq->running_bw; | |
250 | ||
5cb9eaa3 | 251 | lockdep_assert_rq_held(rq_of_dl_rq(dl_rq)); |
e36d8677 LA |
252 | dl_rq->running_bw -= dl_bw; |
253 | SCHED_WARN_ON(dl_rq->running_bw > old); /* underflow */ | |
254 | if (dl_rq->running_bw > old) | |
255 | dl_rq->running_bw = 0; | |
e0367b12 | 256 | /* kick cpufreq (see the comment in kernel/sched/sched.h). */ |
4042d003 | 257 | cpufreq_update_util(rq_of_dl_rq(dl_rq), 0); |
e36d8677 LA |
258 | } |
259 | ||
8fd27231 | 260 | static inline |
794a56eb | 261 | void __add_rq_bw(u64 dl_bw, struct dl_rq *dl_rq) |
8fd27231 LA |
262 | { |
263 | u64 old = dl_rq->this_bw; | |
264 | ||
5cb9eaa3 | 265 | lockdep_assert_rq_held(rq_of_dl_rq(dl_rq)); |
8fd27231 LA |
266 | dl_rq->this_bw += dl_bw; |
267 | SCHED_WARN_ON(dl_rq->this_bw < old); /* overflow */ | |
268 | } | |
269 | ||
270 | static inline | |
794a56eb | 271 | void __sub_rq_bw(u64 dl_bw, struct dl_rq *dl_rq) |
8fd27231 LA |
272 | { |
273 | u64 old = dl_rq->this_bw; | |
274 | ||
5cb9eaa3 | 275 | lockdep_assert_rq_held(rq_of_dl_rq(dl_rq)); |
8fd27231 LA |
276 | dl_rq->this_bw -= dl_bw; |
277 | SCHED_WARN_ON(dl_rq->this_bw > old); /* underflow */ | |
278 | if (dl_rq->this_bw > old) | |
279 | dl_rq->this_bw = 0; | |
280 | SCHED_WARN_ON(dl_rq->running_bw > dl_rq->this_bw); | |
281 | } | |
282 | ||
794a56eb JL |
283 | static inline |
284 | void add_rq_bw(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq) | |
285 | { | |
286 | if (!dl_entity_is_special(dl_se)) | |
287 | __add_rq_bw(dl_se->dl_bw, dl_rq); | |
288 | } | |
289 | ||
290 | static inline | |
291 | void sub_rq_bw(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq) | |
292 | { | |
293 | if (!dl_entity_is_special(dl_se)) | |
294 | __sub_rq_bw(dl_se->dl_bw, dl_rq); | |
295 | } | |
296 | ||
297 | static inline | |
298 | void add_running_bw(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq) | |
299 | { | |
300 | if (!dl_entity_is_special(dl_se)) | |
301 | __add_running_bw(dl_se->dl_bw, dl_rq); | |
302 | } | |
303 | ||
304 | static inline | |
305 | void sub_running_bw(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq) | |
306 | { | |
307 | if (!dl_entity_is_special(dl_se)) | |
308 | __sub_running_bw(dl_se->dl_bw, dl_rq); | |
309 | } | |
310 | ||
ba4f7bc1 | 311 | static void dl_change_utilization(struct task_struct *p, u64 new_bw) |
209a0cbd | 312 | { |
8fd27231 | 313 | struct rq *rq; |
209a0cbd | 314 | |
09348d75 | 315 | WARN_ON_ONCE(p->dl.flags & SCHED_FLAG_SUGOV); |
794a56eb | 316 | |
8fd27231 | 317 | if (task_on_rq_queued(p)) |
209a0cbd LA |
318 | return; |
319 | ||
8fd27231 LA |
320 | rq = task_rq(p); |
321 | if (p->dl.dl_non_contending) { | |
794a56eb | 322 | sub_running_bw(&p->dl, &rq->dl); |
8fd27231 LA |
323 | p->dl.dl_non_contending = 0; |
324 | /* | |
325 | * If the timer handler is currently running and the | |
3b03706f | 326 | * timer cannot be canceled, inactive_task_timer() |
8fd27231 LA |
327 | * will see that dl_not_contending is not set, and |
328 | * will not touch the rq's active utilization, | |
329 | * so we are still safe. | |
330 | */ | |
331 | if (hrtimer_try_to_cancel(&p->dl.inactive_timer) == 1) | |
332 | put_task_struct(p); | |
333 | } | |
794a56eb JL |
334 | __sub_rq_bw(p->dl.dl_bw, &rq->dl); |
335 | __add_rq_bw(new_bw, &rq->dl); | |
209a0cbd LA |
336 | } |
337 | ||
338 | /* | |
339 | * The utilization of a task cannot be immediately removed from | |
340 | * the rq active utilization (running_bw) when the task blocks. | |
341 | * Instead, we have to wait for the so called "0-lag time". | |
342 | * | |
343 | * If a task blocks before the "0-lag time", a timer (the inactive | |
344 | * timer) is armed, and running_bw is decreased when the timer | |
345 | * fires. | |
346 | * | |
347 | * If the task wakes up again before the inactive timer fires, | |
3b03706f | 348 | * the timer is canceled, whereas if the task wakes up after the |
209a0cbd LA |
349 | * inactive timer fired (and running_bw has been decreased) the |
350 | * task's utilization has to be added to running_bw again. | |
351 | * A flag in the deadline scheduling entity (dl_non_contending) | |
352 | * is used to avoid race conditions between the inactive timer handler | |
353 | * and task wakeups. | |
354 | * | |
355 | * The following diagram shows how running_bw is updated. A task is | |
356 | * "ACTIVE" when its utilization contributes to running_bw; an | |
357 | * "ACTIVE contending" task is in the TASK_RUNNING state, while an | |
358 | * "ACTIVE non contending" task is a blocked task for which the "0-lag time" | |
359 | * has not passed yet. An "INACTIVE" task is a task for which the "0-lag" | |
360 | * time already passed, which does not contribute to running_bw anymore. | |
361 | * +------------------+ | |
362 | * wakeup | ACTIVE | | |
363 | * +------------------>+ contending | | |
364 | * | add_running_bw | | | |
365 | * | +----+------+------+ | |
366 | * | | ^ | |
367 | * | dequeue | | | |
368 | * +--------+-------+ | | | |
369 | * | | t >= 0-lag | | wakeup | |
370 | * | INACTIVE |<---------------+ | | |
371 | * | | sub_running_bw | | | |
372 | * +--------+-------+ | | | |
373 | * ^ | | | |
374 | * | t < 0-lag | | | |
375 | * | | | | |
376 | * | V | | |
377 | * | +----+------+------+ | |
378 | * | sub_running_bw | ACTIVE | | |
379 | * +-------------------+ | | |
380 | * inactive timer | non contending | | |
381 | * fired +------------------+ | |
382 | * | |
383 | * The task_non_contending() function is invoked when a task | |
384 | * blocks, and checks if the 0-lag time already passed or | |
385 | * not (in the first case, it directly updates running_bw; | |
386 | * in the second case, it arms the inactive timer). | |
387 | * | |
388 | * The task_contending() function is invoked when a task wakes | |
389 | * up, and checks if the task is still in the "ACTIVE non contending" | |
390 | * state or not (in the second case, it updates running_bw). | |
391 | */ | |
392 | static void task_non_contending(struct task_struct *p) | |
393 | { | |
394 | struct sched_dl_entity *dl_se = &p->dl; | |
395 | struct hrtimer *timer = &dl_se->inactive_timer; | |
396 | struct dl_rq *dl_rq = dl_rq_of_se(dl_se); | |
397 | struct rq *rq = rq_of_dl_rq(dl_rq); | |
398 | s64 zerolag_time; | |
399 | ||
400 | /* | |
401 | * If this is a non-deadline task that has been boosted, | |
402 | * do nothing | |
403 | */ | |
404 | if (dl_se->dl_runtime == 0) | |
405 | return; | |
406 | ||
794a56eb JL |
407 | if (dl_entity_is_special(dl_se)) |
408 | return; | |
409 | ||
209a0cbd LA |
410 | WARN_ON(dl_se->dl_non_contending); |
411 | ||
412 | zerolag_time = dl_se->deadline - | |
413 | div64_long((dl_se->runtime * dl_se->dl_period), | |
414 | dl_se->dl_runtime); | |
415 | ||
416 | /* | |
417 | * Using relative times instead of the absolute "0-lag time" | |
418 | * allows to simplify the code | |
419 | */ | |
420 | zerolag_time -= rq_clock(rq); | |
421 | ||
422 | /* | |
423 | * If the "0-lag time" already passed, decrease the active | |
424 | * utilization now, instead of starting a timer | |
425 | */ | |
1b02cd6a | 426 | if ((zerolag_time < 0) || hrtimer_active(&dl_se->inactive_timer)) { |
209a0cbd | 427 | if (dl_task(p)) |
794a56eb | 428 | sub_running_bw(dl_se, dl_rq); |
2f064a59 | 429 | if (!dl_task(p) || READ_ONCE(p->__state) == TASK_DEAD) { |
387e3130 LA |
430 | struct dl_bw *dl_b = dl_bw_of(task_cpu(p)); |
431 | ||
2f064a59 | 432 | if (READ_ONCE(p->__state) == TASK_DEAD) |
794a56eb | 433 | sub_rq_bw(&p->dl, &rq->dl); |
387e3130 | 434 | raw_spin_lock(&dl_b->lock); |
8c0944ce | 435 | __dl_sub(dl_b, p->dl.dl_bw, dl_bw_cpus(task_cpu(p))); |
387e3130 | 436 | raw_spin_unlock(&dl_b->lock); |
33f93525 | 437 | __dl_clear_params(p); |
387e3130 | 438 | } |
209a0cbd LA |
439 | |
440 | return; | |
441 | } | |
442 | ||
443 | dl_se->dl_non_contending = 1; | |
444 | get_task_struct(p); | |
850377a8 | 445 | hrtimer_start(timer, ns_to_ktime(zerolag_time), HRTIMER_MODE_REL_HARD); |
209a0cbd LA |
446 | } |
447 | ||
8fd27231 | 448 | static void task_contending(struct sched_dl_entity *dl_se, int flags) |
209a0cbd LA |
449 | { |
450 | struct dl_rq *dl_rq = dl_rq_of_se(dl_se); | |
451 | ||
452 | /* | |
453 | * If this is a non-deadline task that has been boosted, | |
454 | * do nothing | |
455 | */ | |
456 | if (dl_se->dl_runtime == 0) | |
457 | return; | |
458 | ||
8fd27231 | 459 | if (flags & ENQUEUE_MIGRATED) |
794a56eb | 460 | add_rq_bw(dl_se, dl_rq); |
8fd27231 | 461 | |
209a0cbd LA |
462 | if (dl_se->dl_non_contending) { |
463 | dl_se->dl_non_contending = 0; | |
464 | /* | |
465 | * If the timer handler is currently running and the | |
3b03706f | 466 | * timer cannot be canceled, inactive_task_timer() |
209a0cbd LA |
467 | * will see that dl_not_contending is not set, and |
468 | * will not touch the rq's active utilization, | |
469 | * so we are still safe. | |
470 | */ | |
471 | if (hrtimer_try_to_cancel(&dl_se->inactive_timer) == 1) | |
472 | put_task_struct(dl_task_of(dl_se)); | |
473 | } else { | |
474 | /* | |
475 | * Since "dl_non_contending" is not set, the | |
476 | * task's utilization has already been removed from | |
477 | * active utilization (either when the task blocked, | |
478 | * when the "inactive timer" fired). | |
479 | * So, add it back. | |
480 | */ | |
794a56eb | 481 | add_running_bw(dl_se, dl_rq); |
209a0cbd LA |
482 | } |
483 | } | |
484 | ||
aab03e05 DF |
485 | static inline int is_leftmost(struct task_struct *p, struct dl_rq *dl_rq) |
486 | { | |
487 | struct sched_dl_entity *dl_se = &p->dl; | |
488 | ||
f4478e7c | 489 | return rb_first_cached(&dl_rq->root) == &dl_se->rb_node; |
aab03e05 DF |
490 | } |
491 | ||
ba4f7bc1 YC |
492 | static void init_dl_rq_bw_ratio(struct dl_rq *dl_rq); |
493 | ||
332ac17e DF |
494 | void init_dl_bw(struct dl_bw *dl_b) |
495 | { | |
496 | raw_spin_lock_init(&dl_b->lock); | |
1724813d | 497 | if (global_rt_runtime() == RUNTIME_INF) |
332ac17e DF |
498 | dl_b->bw = -1; |
499 | else | |
1724813d | 500 | dl_b->bw = to_ratio(global_rt_period(), global_rt_runtime()); |
332ac17e DF |
501 | dl_b->total_bw = 0; |
502 | } | |
503 | ||
07c54f7a | 504 | void init_dl_rq(struct dl_rq *dl_rq) |
aab03e05 | 505 | { |
2161573e | 506 | dl_rq->root = RB_ROOT_CACHED; |
1baca4ce JL |
507 | |
508 | #ifdef CONFIG_SMP | |
509 | /* zero means no -deadline tasks */ | |
510 | dl_rq->earliest_dl.curr = dl_rq->earliest_dl.next = 0; | |
511 | ||
1baca4ce | 512 | dl_rq->overloaded = 0; |
2161573e | 513 | dl_rq->pushable_dl_tasks_root = RB_ROOT_CACHED; |
332ac17e DF |
514 | #else |
515 | init_dl_bw(&dl_rq->dl_bw); | |
1baca4ce | 516 | #endif |
e36d8677 LA |
517 | |
518 | dl_rq->running_bw = 0; | |
8fd27231 | 519 | dl_rq->this_bw = 0; |
4da3abce | 520 | init_dl_rq_bw_ratio(dl_rq); |
1baca4ce JL |
521 | } |
522 | ||
523 | #ifdef CONFIG_SMP | |
524 | ||
525 | static inline int dl_overloaded(struct rq *rq) | |
526 | { | |
527 | return atomic_read(&rq->rd->dlo_count); | |
528 | } | |
529 | ||
530 | static inline void dl_set_overload(struct rq *rq) | |
531 | { | |
532 | if (!rq->online) | |
533 | return; | |
534 | ||
535 | cpumask_set_cpu(rq->cpu, rq->rd->dlo_mask); | |
536 | /* | |
537 | * Must be visible before the overload count is | |
538 | * set (as in sched_rt.c). | |
539 | * | |
540 | * Matched by the barrier in pull_dl_task(). | |
541 | */ | |
542 | smp_wmb(); | |
543 | atomic_inc(&rq->rd->dlo_count); | |
544 | } | |
545 | ||
546 | static inline void dl_clear_overload(struct rq *rq) | |
547 | { | |
548 | if (!rq->online) | |
549 | return; | |
550 | ||
551 | atomic_dec(&rq->rd->dlo_count); | |
552 | cpumask_clear_cpu(rq->cpu, rq->rd->dlo_mask); | |
553 | } | |
554 | ||
8ecca394 PZ |
555 | #define __node_2_pdl(node) \ |
556 | rb_entry((node), struct task_struct, pushable_dl_tasks) | |
557 | ||
558 | static inline bool __pushable_less(struct rb_node *a, const struct rb_node *b) | |
559 | { | |
560 | return dl_entity_preempt(&__node_2_pdl(a)->dl, &__node_2_pdl(b)->dl); | |
561 | } | |
562 | ||
5fe77659 VS |
563 | static inline int has_pushable_dl_tasks(struct rq *rq) |
564 | { | |
565 | return !RB_EMPTY_ROOT(&rq->dl.pushable_dl_tasks_root.rb_root); | |
566 | } | |
567 | ||
1baca4ce JL |
568 | /* |
569 | * The list of pushable -deadline task is not a plist, like in | |
570 | * sched_rt.c, it is an rb-tree with tasks ordered by deadline. | |
571 | */ | |
572 | static void enqueue_pushable_dl_task(struct rq *rq, struct task_struct *p) | |
573 | { | |
8ecca394 | 574 | struct rb_node *leftmost; |
1baca4ce | 575 | |
09348d75 | 576 | WARN_ON_ONCE(!RB_EMPTY_NODE(&p->pushable_dl_tasks)); |
1baca4ce | 577 | |
8ecca394 PZ |
578 | leftmost = rb_add_cached(&p->pushable_dl_tasks, |
579 | &rq->dl.pushable_dl_tasks_root, | |
580 | __pushable_less); | |
2161573e | 581 | if (leftmost) |
8ecca394 | 582 | rq->dl.earliest_dl.next = p->dl.deadline; |
5fe77659 VS |
583 | |
584 | if (!rq->dl.overloaded) { | |
585 | dl_set_overload(rq); | |
586 | rq->dl.overloaded = 1; | |
587 | } | |
aab03e05 DF |
588 | } |
589 | ||
1baca4ce JL |
590 | static void dequeue_pushable_dl_task(struct rq *rq, struct task_struct *p) |
591 | { | |
592 | struct dl_rq *dl_rq = &rq->dl; | |
8ecca394 PZ |
593 | struct rb_root_cached *root = &dl_rq->pushable_dl_tasks_root; |
594 | struct rb_node *leftmost; | |
1baca4ce JL |
595 | |
596 | if (RB_EMPTY_NODE(&p->pushable_dl_tasks)) | |
597 | return; | |
598 | ||
8ecca394 PZ |
599 | leftmost = rb_erase_cached(&p->pushable_dl_tasks, root); |
600 | if (leftmost) | |
601 | dl_rq->earliest_dl.next = __node_2_pdl(leftmost)->dl.deadline; | |
1baca4ce | 602 | |
1baca4ce | 603 | RB_CLEAR_NODE(&p->pushable_dl_tasks); |
1baca4ce | 604 | |
5fe77659 VS |
605 | if (!has_pushable_dl_tasks(rq) && rq->dl.overloaded) { |
606 | dl_clear_overload(rq); | |
607 | rq->dl.overloaded = 0; | |
608 | } | |
1baca4ce JL |
609 | } |
610 | ||
611 | static int push_dl_task(struct rq *rq); | |
612 | ||
dc877341 PZ |
613 | static inline bool need_pull_dl_task(struct rq *rq, struct task_struct *prev) |
614 | { | |
120455c5 | 615 | return rq->online && dl_task(prev); |
dc877341 PZ |
616 | } |
617 | ||
8e5bad7d KC |
618 | static DEFINE_PER_CPU(struct balance_callback, dl_push_head); |
619 | static DEFINE_PER_CPU(struct balance_callback, dl_pull_head); | |
e3fca9e7 PZ |
620 | |
621 | static void push_dl_tasks(struct rq *); | |
9916e214 | 622 | static void pull_dl_task(struct rq *); |
e3fca9e7 | 623 | |
02d8ec94 | 624 | static inline void deadline_queue_push_tasks(struct rq *rq) |
dc877341 | 625 | { |
e3fca9e7 PZ |
626 | if (!has_pushable_dl_tasks(rq)) |
627 | return; | |
628 | ||
9916e214 PZ |
629 | queue_balance_callback(rq, &per_cpu(dl_push_head, rq->cpu), push_dl_tasks); |
630 | } | |
631 | ||
02d8ec94 | 632 | static inline void deadline_queue_pull_task(struct rq *rq) |
9916e214 PZ |
633 | { |
634 | queue_balance_callback(rq, &per_cpu(dl_pull_head, rq->cpu), pull_dl_task); | |
dc877341 PZ |
635 | } |
636 | ||
fa9c9d10 WL |
637 | static struct rq *find_lock_later_rq(struct task_struct *task, struct rq *rq); |
638 | ||
a649f237 | 639 | static struct rq *dl_task_offline_migration(struct rq *rq, struct task_struct *p) |
fa9c9d10 WL |
640 | { |
641 | struct rq *later_rq = NULL; | |
59d06cea | 642 | struct dl_bw *dl_b; |
fa9c9d10 WL |
643 | |
644 | later_rq = find_lock_later_rq(p, rq); | |
fa9c9d10 WL |
645 | if (!later_rq) { |
646 | int cpu; | |
647 | ||
648 | /* | |
649 | * If we cannot preempt any rq, fall back to pick any | |
97fb7a0a | 650 | * online CPU: |
fa9c9d10 | 651 | */ |
3bd37062 | 652 | cpu = cpumask_any_and(cpu_active_mask, p->cpus_ptr); |
fa9c9d10 WL |
653 | if (cpu >= nr_cpu_ids) { |
654 | /* | |
97fb7a0a | 655 | * Failed to find any suitable CPU. |
fa9c9d10 WL |
656 | * The task will never come back! |
657 | */ | |
09348d75 | 658 | WARN_ON_ONCE(dl_bandwidth_enabled()); |
fa9c9d10 WL |
659 | |
660 | /* | |
661 | * If admission control is disabled we | |
662 | * try a little harder to let the task | |
663 | * run. | |
664 | */ | |
665 | cpu = cpumask_any(cpu_active_mask); | |
666 | } | |
667 | later_rq = cpu_rq(cpu); | |
668 | double_lock_balance(rq, later_rq); | |
669 | } | |
670 | ||
59d06cea JL |
671 | if (p->dl.dl_non_contending || p->dl.dl_throttled) { |
672 | /* | |
673 | * Inactive timer is armed (or callback is running, but | |
674 | * waiting for us to release rq locks). In any case, when it | |
675 | * will fire (or continue), it will see running_bw of this | |
676 | * task migrated to later_rq (and correctly handle it). | |
677 | */ | |
678 | sub_running_bw(&p->dl, &rq->dl); | |
679 | sub_rq_bw(&p->dl, &rq->dl); | |
680 | ||
681 | add_rq_bw(&p->dl, &later_rq->dl); | |
682 | add_running_bw(&p->dl, &later_rq->dl); | |
683 | } else { | |
684 | sub_rq_bw(&p->dl, &rq->dl); | |
685 | add_rq_bw(&p->dl, &later_rq->dl); | |
686 | } | |
687 | ||
688 | /* | |
689 | * And we finally need to fixup root_domain(s) bandwidth accounting, | |
690 | * since p is still hanging out in the old (now moved to default) root | |
691 | * domain. | |
692 | */ | |
693 | dl_b = &rq->rd->dl_bw; | |
694 | raw_spin_lock(&dl_b->lock); | |
695 | __dl_sub(dl_b, p->dl.dl_bw, cpumask_weight(rq->rd->span)); | |
696 | raw_spin_unlock(&dl_b->lock); | |
697 | ||
698 | dl_b = &later_rq->rd->dl_bw; | |
699 | raw_spin_lock(&dl_b->lock); | |
700 | __dl_add(dl_b, p->dl.dl_bw, cpumask_weight(later_rq->rd->span)); | |
701 | raw_spin_unlock(&dl_b->lock); | |
702 | ||
fa9c9d10 | 703 | set_task_cpu(p, later_rq->cpu); |
a649f237 PZ |
704 | double_unlock_balance(later_rq, rq); |
705 | ||
706 | return later_rq; | |
fa9c9d10 WL |
707 | } |
708 | ||
1baca4ce JL |
709 | #else |
710 | ||
711 | static inline | |
712 | void enqueue_pushable_dl_task(struct rq *rq, struct task_struct *p) | |
713 | { | |
714 | } | |
715 | ||
716 | static inline | |
717 | void dequeue_pushable_dl_task(struct rq *rq, struct task_struct *p) | |
718 | { | |
719 | } | |
720 | ||
721 | static inline | |
722 | void inc_dl_migration(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq) | |
723 | { | |
724 | } | |
725 | ||
726 | static inline | |
727 | void dec_dl_migration(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq) | |
728 | { | |
729 | } | |
730 | ||
02d8ec94 | 731 | static inline void deadline_queue_push_tasks(struct rq *rq) |
dc877341 | 732 | { |
dc877341 PZ |
733 | } |
734 | ||
02d8ec94 | 735 | static inline void deadline_queue_pull_task(struct rq *rq) |
dc877341 PZ |
736 | { |
737 | } | |
1baca4ce JL |
738 | #endif /* CONFIG_SMP */ |
739 | ||
aab03e05 DF |
740 | static void enqueue_task_dl(struct rq *rq, struct task_struct *p, int flags); |
741 | static void __dequeue_task_dl(struct rq *rq, struct task_struct *p, int flags); | |
e23edc86 | 742 | static void wakeup_preempt_dl(struct rq *rq, struct task_struct *p, int flags); |
aab03e05 | 743 | |
96458e7f SX |
744 | static inline void replenish_dl_new_period(struct sched_dl_entity *dl_se, |
745 | struct rq *rq) | |
746 | { | |
747 | /* for non-boosted task, pi_of(dl_se) == dl_se */ | |
748 | dl_se->deadline = rq_clock(rq) + pi_of(dl_se)->dl_deadline; | |
749 | dl_se->runtime = pi_of(dl_se)->dl_runtime; | |
750 | } | |
751 | ||
aab03e05 DF |
752 | /* |
753 | * We are being explicitly informed that a new instance is starting, | |
754 | * and this means that: | |
755 | * - the absolute deadline of the entity has to be placed at | |
756 | * current time + relative deadline; | |
757 | * - the runtime of the entity has to be set to the maximum value. | |
758 | * | |
759 | * The capability of specifying such event is useful whenever a -deadline | |
760 | * entity wants to (try to!) synchronize its behaviour with the scheduler's | |
761 | * one, and to (try to!) reconcile itself with its own scheduling | |
762 | * parameters. | |
763 | */ | |
98b0a857 | 764 | static inline void setup_new_dl_entity(struct sched_dl_entity *dl_se) |
aab03e05 DF |
765 | { |
766 | struct dl_rq *dl_rq = dl_rq_of_se(dl_se); | |
767 | struct rq *rq = rq_of_dl_rq(dl_rq); | |
768 | ||
2279f540 | 769 | WARN_ON(is_dl_boosted(dl_se)); |
72f9f3fd LA |
770 | WARN_ON(dl_time_before(rq_clock(rq), dl_se->deadline)); |
771 | ||
772 | /* | |
773 | * We are racing with the deadline timer. So, do nothing because | |
774 | * the deadline timer handler will take care of properly recharging | |
775 | * the runtime and postponing the deadline | |
776 | */ | |
777 | if (dl_se->dl_throttled) | |
778 | return; | |
aab03e05 DF |
779 | |
780 | /* | |
781 | * We use the regular wall clock time to set deadlines in the | |
782 | * future; in fact, we must consider execution overheads (time | |
783 | * spent on hardirq context, etc.). | |
784 | */ | |
96458e7f | 785 | replenish_dl_new_period(dl_se, rq); |
aab03e05 DF |
786 | } |
787 | ||
788 | /* | |
789 | * Pure Earliest Deadline First (EDF) scheduling does not deal with the | |
790 | * possibility of a entity lasting more than what it declared, and thus | |
791 | * exhausting its runtime. | |
792 | * | |
793 | * Here we are interested in making runtime overrun possible, but we do | |
794 | * not want a entity which is misbehaving to affect the scheduling of all | |
795 | * other entities. | |
796 | * Therefore, a budgeting strategy called Constant Bandwidth Server (CBS) | |
797 | * is used, in order to confine each entity within its own bandwidth. | |
798 | * | |
799 | * This function deals exactly with that, and ensures that when the runtime | |
800 | * of a entity is replenished, its deadline is also postponed. That ensures | |
801 | * the overrunning entity can't interfere with other entity in the system and | |
802 | * can't make them miss their deadlines. Reasons why this kind of overruns | |
803 | * could happen are, typically, a entity voluntarily trying to overcome its | |
1b09d29b | 804 | * runtime, or it just underestimated it during sched_setattr(). |
aab03e05 | 805 | */ |
2279f540 | 806 | static void replenish_dl_entity(struct sched_dl_entity *dl_se) |
aab03e05 DF |
807 | { |
808 | struct dl_rq *dl_rq = dl_rq_of_se(dl_se); | |
809 | struct rq *rq = rq_of_dl_rq(dl_rq); | |
810 | ||
09348d75 | 811 | WARN_ON_ONCE(pi_of(dl_se)->dl_runtime <= 0); |
2d3d891d DF |
812 | |
813 | /* | |
814 | * This could be the case for a !-dl task that is boosted. | |
815 | * Just go with full inherited parameters. | |
816 | */ | |
96458e7f SX |
817 | if (dl_se->dl_deadline == 0) |
818 | replenish_dl_new_period(dl_se, rq); | |
2d3d891d | 819 | |
48be3a67 PZ |
820 | if (dl_se->dl_yielded && dl_se->runtime > 0) |
821 | dl_se->runtime = 0; | |
822 | ||
aab03e05 DF |
823 | /* |
824 | * We keep moving the deadline away until we get some | |
825 | * available runtime for the entity. This ensures correct | |
826 | * handling of situations where the runtime overrun is | |
827 | * arbitrary large. | |
828 | */ | |
829 | while (dl_se->runtime <= 0) { | |
2279f540 JL |
830 | dl_se->deadline += pi_of(dl_se)->dl_period; |
831 | dl_se->runtime += pi_of(dl_se)->dl_runtime; | |
aab03e05 DF |
832 | } |
833 | ||
834 | /* | |
835 | * At this point, the deadline really should be "in | |
836 | * the future" with respect to rq->clock. If it's | |
837 | * not, we are, for some reason, lagging too much! | |
838 | * Anyway, after having warn userspace abut that, | |
839 | * we still try to keep the things running by | |
840 | * resetting the deadline and the budget of the | |
841 | * entity. | |
842 | */ | |
843 | if (dl_time_before(dl_se->deadline, rq_clock(rq))) { | |
c219b7dd | 844 | printk_deferred_once("sched: DL replenish lagged too much\n"); |
96458e7f | 845 | replenish_dl_new_period(dl_se, rq); |
aab03e05 | 846 | } |
1019a359 PZ |
847 | |
848 | if (dl_se->dl_yielded) | |
849 | dl_se->dl_yielded = 0; | |
850 | if (dl_se->dl_throttled) | |
851 | dl_se->dl_throttled = 0; | |
aab03e05 DF |
852 | } |
853 | ||
854 | /* | |
855 | * Here we check if --at time t-- an entity (which is probably being | |
856 | * [re]activated or, in general, enqueued) can use its remaining runtime | |
857 | * and its current deadline _without_ exceeding the bandwidth it is | |
858 | * assigned (function returns true if it can't). We are in fact applying | |
859 | * one of the CBS rules: when a task wakes up, if the residual runtime | |
860 | * over residual deadline fits within the allocated bandwidth, then we | |
861 | * can keep the current (absolute) deadline and residual budget without | |
862 | * disrupting the schedulability of the system. Otherwise, we should | |
863 | * refill the runtime and set the deadline a period in the future, | |
864 | * because keeping the current (absolute) deadline of the task would | |
712e5e34 | 865 | * result in breaking guarantees promised to other tasks (refer to |
d6a3b247 | 866 | * Documentation/scheduler/sched-deadline.rst for more information). |
aab03e05 DF |
867 | * |
868 | * This function returns true if: | |
869 | * | |
2317d5f1 | 870 | * runtime / (deadline - t) > dl_runtime / dl_deadline , |
aab03e05 DF |
871 | * |
872 | * IOW we can't recycle current parameters. | |
755378a4 | 873 | * |
2317d5f1 | 874 | * Notice that the bandwidth check is done against the deadline. For |
755378a4 | 875 | * task with deadline equal to period this is the same of using |
2317d5f1 | 876 | * dl_period instead of dl_deadline in the equation above. |
aab03e05 | 877 | */ |
2279f540 | 878 | static bool dl_entity_overflow(struct sched_dl_entity *dl_se, u64 t) |
aab03e05 DF |
879 | { |
880 | u64 left, right; | |
881 | ||
882 | /* | |
883 | * left and right are the two sides of the equation above, | |
884 | * after a bit of shuffling to use multiplications instead | |
885 | * of divisions. | |
886 | * | |
887 | * Note that none of the time values involved in the two | |
888 | * multiplications are absolute: dl_deadline and dl_runtime | |
889 | * are the relative deadline and the maximum runtime of each | |
890 | * instance, runtime is the runtime left for the last instance | |
891 | * and (deadline - t), since t is rq->clock, is the time left | |
892 | * to the (absolute) deadline. Even if overflowing the u64 type | |
893 | * is very unlikely to occur in both cases, here we scale down | |
894 | * as we want to avoid that risk at all. Scaling down by 10 | |
895 | * means that we reduce granularity to 1us. We are fine with it, | |
896 | * since this is only a true/false check and, anyway, thinking | |
897 | * of anything below microseconds resolution is actually fiction | |
898 | * (but still we want to give the user that illusion >;). | |
899 | */ | |
2279f540 | 900 | left = (pi_of(dl_se)->dl_deadline >> DL_SCALE) * (dl_se->runtime >> DL_SCALE); |
332ac17e | 901 | right = ((dl_se->deadline - t) >> DL_SCALE) * |
2279f540 | 902 | (pi_of(dl_se)->dl_runtime >> DL_SCALE); |
aab03e05 DF |
903 | |
904 | return dl_time_before(right, left); | |
905 | } | |
906 | ||
907 | /* | |
3effcb42 DBO |
908 | * Revised wakeup rule [1]: For self-suspending tasks, rather then |
909 | * re-initializing task's runtime and deadline, the revised wakeup | |
910 | * rule adjusts the task's runtime to avoid the task to overrun its | |
911 | * density. | |
aab03e05 | 912 | * |
3effcb42 DBO |
913 | * Reasoning: a task may overrun the density if: |
914 | * runtime / (deadline - t) > dl_runtime / dl_deadline | |
915 | * | |
916 | * Therefore, runtime can be adjusted to: | |
917 | * runtime = (dl_runtime / dl_deadline) * (deadline - t) | |
918 | * | |
919 | * In such way that runtime will be equal to the maximum density | |
920 | * the task can use without breaking any rule. | |
921 | * | |
922 | * [1] Luca Abeni, Giuseppe Lipari, and Juri Lelli. 2015. Constant | |
923 | * bandwidth server revisited. SIGBED Rev. 11, 4 (January 2015), 19-24. | |
924 | */ | |
925 | static void | |
926 | update_dl_revised_wakeup(struct sched_dl_entity *dl_se, struct rq *rq) | |
927 | { | |
928 | u64 laxity = dl_se->deadline - rq_clock(rq); | |
929 | ||
930 | /* | |
931 | * If the task has deadline < period, and the deadline is in the past, | |
932 | * it should already be throttled before this check. | |
933 | * | |
934 | * See update_dl_entity() comments for further details. | |
935 | */ | |
936 | WARN_ON(dl_time_before(dl_se->deadline, rq_clock(rq))); | |
937 | ||
938 | dl_se->runtime = (dl_se->dl_density * laxity) >> BW_SHIFT; | |
939 | } | |
940 | ||
941 | /* | |
942 | * Regarding the deadline, a task with implicit deadline has a relative | |
943 | * deadline == relative period. A task with constrained deadline has a | |
944 | * relative deadline <= relative period. | |
945 | * | |
946 | * We support constrained deadline tasks. However, there are some restrictions | |
947 | * applied only for tasks which do not have an implicit deadline. See | |
948 | * update_dl_entity() to know more about such restrictions. | |
949 | * | |
950 | * The dl_is_implicit() returns true if the task has an implicit deadline. | |
951 | */ | |
952 | static inline bool dl_is_implicit(struct sched_dl_entity *dl_se) | |
953 | { | |
954 | return dl_se->dl_deadline == dl_se->dl_period; | |
955 | } | |
956 | ||
957 | /* | |
958 | * When a deadline entity is placed in the runqueue, its runtime and deadline | |
959 | * might need to be updated. This is done by a CBS wake up rule. There are two | |
960 | * different rules: 1) the original CBS; and 2) the Revisited CBS. | |
961 | * | |
962 | * When the task is starting a new period, the Original CBS is used. In this | |
963 | * case, the runtime is replenished and a new absolute deadline is set. | |
964 | * | |
965 | * When a task is queued before the begin of the next period, using the | |
966 | * remaining runtime and deadline could make the entity to overflow, see | |
967 | * dl_entity_overflow() to find more about runtime overflow. When such case | |
968 | * is detected, the runtime and deadline need to be updated. | |
969 | * | |
970 | * If the task has an implicit deadline, i.e., deadline == period, the Original | |
971 | * CBS is applied. the runtime is replenished and a new absolute deadline is | |
972 | * set, as in the previous cases. | |
973 | * | |
974 | * However, the Original CBS does not work properly for tasks with | |
975 | * deadline < period, which are said to have a constrained deadline. By | |
976 | * applying the Original CBS, a constrained deadline task would be able to run | |
977 | * runtime/deadline in a period. With deadline < period, the task would | |
978 | * overrun the runtime/period allowed bandwidth, breaking the admission test. | |
979 | * | |
980 | * In order to prevent this misbehave, the Revisited CBS is used for | |
981 | * constrained deadline tasks when a runtime overflow is detected. In the | |
982 | * Revisited CBS, rather than replenishing & setting a new absolute deadline, | |
983 | * the remaining runtime of the task is reduced to avoid runtime overflow. | |
984 | * Please refer to the comments update_dl_revised_wakeup() function to find | |
985 | * more about the Revised CBS rule. | |
aab03e05 | 986 | */ |
2279f540 | 987 | static void update_dl_entity(struct sched_dl_entity *dl_se) |
aab03e05 DF |
988 | { |
989 | struct dl_rq *dl_rq = dl_rq_of_se(dl_se); | |
990 | struct rq *rq = rq_of_dl_rq(dl_rq); | |
991 | ||
aab03e05 | 992 | if (dl_time_before(dl_se->deadline, rq_clock(rq)) || |
2279f540 | 993 | dl_entity_overflow(dl_se, rq_clock(rq))) { |
3effcb42 DBO |
994 | |
995 | if (unlikely(!dl_is_implicit(dl_se) && | |
996 | !dl_time_before(dl_se->deadline, rq_clock(rq)) && | |
2279f540 | 997 | !is_dl_boosted(dl_se))) { |
3effcb42 DBO |
998 | update_dl_revised_wakeup(dl_se, rq); |
999 | return; | |
1000 | } | |
1001 | ||
96458e7f | 1002 | replenish_dl_new_period(dl_se, rq); |
aab03e05 DF |
1003 | } |
1004 | } | |
1005 | ||
5ac69d37 DBO |
1006 | static inline u64 dl_next_period(struct sched_dl_entity *dl_se) |
1007 | { | |
1008 | return dl_se->deadline - dl_se->dl_deadline + dl_se->dl_period; | |
1009 | } | |
1010 | ||
aab03e05 DF |
1011 | /* |
1012 | * If the entity depleted all its runtime, and if we want it to sleep | |
1013 | * while waiting for some new execution time to become available, we | |
5ac69d37 | 1014 | * set the bandwidth replenishment timer to the replenishment instant |
aab03e05 DF |
1015 | * and try to activate it. |
1016 | * | |
1017 | * Notice that it is important for the caller to know if the timer | |
1018 | * actually started or not (i.e., the replenishment instant is in | |
1019 | * the future or in the past). | |
1020 | */ | |
a649f237 | 1021 | static int start_dl_timer(struct task_struct *p) |
aab03e05 | 1022 | { |
a649f237 PZ |
1023 | struct sched_dl_entity *dl_se = &p->dl; |
1024 | struct hrtimer *timer = &dl_se->dl_timer; | |
1025 | struct rq *rq = task_rq(p); | |
aab03e05 | 1026 | ktime_t now, act; |
aab03e05 DF |
1027 | s64 delta; |
1028 | ||
5cb9eaa3 | 1029 | lockdep_assert_rq_held(rq); |
a649f237 | 1030 | |
aab03e05 DF |
1031 | /* |
1032 | * We want the timer to fire at the deadline, but considering | |
1033 | * that it is actually coming from rq->clock and not from | |
1034 | * hrtimer's time base reading. | |
1035 | */ | |
5ac69d37 | 1036 | act = ns_to_ktime(dl_next_period(dl_se)); |
a649f237 | 1037 | now = hrtimer_cb_get_time(timer); |
aab03e05 DF |
1038 | delta = ktime_to_ns(now) - rq_clock(rq); |
1039 | act = ktime_add_ns(act, delta); | |
1040 | ||
1041 | /* | |
1042 | * If the expiry time already passed, e.g., because the value | |
1043 | * chosen as the deadline is too small, don't even try to | |
1044 | * start the timer in the past! | |
1045 | */ | |
1046 | if (ktime_us_delta(act, now) < 0) | |
1047 | return 0; | |
1048 | ||
a649f237 PZ |
1049 | /* |
1050 | * !enqueued will guarantee another callback; even if one is already in | |
1051 | * progress. This ensures a balanced {get,put}_task_struct(). | |
1052 | * | |
1053 | * The race against __run_timer() clearing the enqueued state is | |
1054 | * harmless because we're holding task_rq()->lock, therefore the timer | |
1055 | * expiring after we've done the check will wait on its task_rq_lock() | |
1056 | * and observe our state. | |
1057 | */ | |
1058 | if (!hrtimer_is_queued(timer)) { | |
1059 | get_task_struct(p); | |
d5096aa6 | 1060 | hrtimer_start(timer, act, HRTIMER_MODE_ABS_HARD); |
a649f237 | 1061 | } |
aab03e05 | 1062 | |
cc9684d3 | 1063 | return 1; |
aab03e05 DF |
1064 | } |
1065 | ||
1066 | /* | |
1067 | * This is the bandwidth enforcement timer callback. If here, we know | |
1068 | * a task is not on its dl_rq, since the fact that the timer was running | |
1069 | * means the task is throttled and needs a runtime replenishment. | |
1070 | * | |
1071 | * However, what we actually do depends on the fact the task is active, | |
1072 | * (it is on its rq) or has been removed from there by a call to | |
1073 | * dequeue_task_dl(). In the former case we must issue the runtime | |
1074 | * replenishment and add the task back to the dl_rq; in the latter, we just | |
1075 | * do nothing but clearing dl_throttled, so that runtime and deadline | |
1076 | * updating (and the queueing back to dl_rq) will be done by the | |
1077 | * next call to enqueue_task_dl(). | |
1078 | */ | |
1079 | static enum hrtimer_restart dl_task_timer(struct hrtimer *timer) | |
1080 | { | |
1081 | struct sched_dl_entity *dl_se = container_of(timer, | |
1082 | struct sched_dl_entity, | |
1083 | dl_timer); | |
1084 | struct task_struct *p = dl_task_of(dl_se); | |
eb580751 | 1085 | struct rq_flags rf; |
0f397f2c | 1086 | struct rq *rq; |
3960c8c0 | 1087 | |
eb580751 | 1088 | rq = task_rq_lock(p, &rf); |
0f397f2c | 1089 | |
aab03e05 | 1090 | /* |
a649f237 | 1091 | * The task might have changed its scheduling policy to something |
9846d50d | 1092 | * different than SCHED_DEADLINE (through switched_from_dl()). |
a649f237 | 1093 | */ |
209a0cbd | 1094 | if (!dl_task(p)) |
a649f237 | 1095 | goto unlock; |
a649f237 | 1096 | |
a649f237 PZ |
1097 | /* |
1098 | * The task might have been boosted by someone else and might be in the | |
1099 | * boosting/deboosting path, its not throttled. | |
1100 | */ | |
2279f540 | 1101 | if (is_dl_boosted(dl_se)) |
a649f237 | 1102 | goto unlock; |
a79ec89f | 1103 | |
fa9c9d10 | 1104 | /* |
a649f237 PZ |
1105 | * Spurious timer due to start_dl_timer() race; or we already received |
1106 | * a replenishment from rt_mutex_setprio(). | |
fa9c9d10 | 1107 | */ |
a649f237 | 1108 | if (!dl_se->dl_throttled) |
fa9c9d10 | 1109 | goto unlock; |
a649f237 PZ |
1110 | |
1111 | sched_clock_tick(); | |
1112 | update_rq_clock(rq); | |
fa9c9d10 | 1113 | |
a79ec89f KT |
1114 | /* |
1115 | * If the throttle happened during sched-out; like: | |
1116 | * | |
1117 | * schedule() | |
1118 | * deactivate_task() | |
1119 | * dequeue_task_dl() | |
1120 | * update_curr_dl() | |
1121 | * start_dl_timer() | |
1122 | * __dequeue_task_dl() | |
1123 | * prev->on_rq = 0; | |
1124 | * | |
1125 | * We can be both throttled and !queued. Replenish the counter | |
1126 | * but do not enqueue -- wait for our wakeup to do that. | |
1127 | */ | |
1128 | if (!task_on_rq_queued(p)) { | |
2279f540 | 1129 | replenish_dl_entity(dl_se); |
a79ec89f KT |
1130 | goto unlock; |
1131 | } | |
1132 | ||
1baca4ce | 1133 | #ifdef CONFIG_SMP |
c0c8c9fa | 1134 | if (unlikely(!rq->online)) { |
61c7aca6 WL |
1135 | /* |
1136 | * If the runqueue is no longer available, migrate the | |
1137 | * task elsewhere. This necessarily changes rq. | |
1138 | */ | |
9ef7e7e3 | 1139 | lockdep_unpin_lock(__rq_lockp(rq), rf.cookie); |
a649f237 | 1140 | rq = dl_task_offline_migration(rq, p); |
9ef7e7e3 | 1141 | rf.cookie = lockdep_pin_lock(__rq_lockp(rq)); |
dcc3b5ff | 1142 | update_rq_clock(rq); |
61c7aca6 WL |
1143 | |
1144 | /* | |
1145 | * Now that the task has been migrated to the new RQ and we | |
1146 | * have that locked, proceed as normal and enqueue the task | |
1147 | * there. | |
1148 | */ | |
c0c8c9fa | 1149 | } |
61c7aca6 | 1150 | #endif |
a649f237 | 1151 | |
61c7aca6 WL |
1152 | enqueue_task_dl(rq, p, ENQUEUE_REPLENISH); |
1153 | if (dl_task(rq->curr)) | |
e23edc86 | 1154 | wakeup_preempt_dl(rq, p, 0); |
61c7aca6 WL |
1155 | else |
1156 | resched_curr(rq); | |
a649f237 | 1157 | |
61c7aca6 | 1158 | #ifdef CONFIG_SMP |
a649f237 PZ |
1159 | /* |
1160 | * Queueing this task back might have overloaded rq, check if we need | |
1161 | * to kick someone away. | |
1019a359 | 1162 | */ |
0aaafaab PZ |
1163 | if (has_pushable_dl_tasks(rq)) { |
1164 | /* | |
1165 | * Nothing relies on rq->lock after this, so its safe to drop | |
1166 | * rq->lock. | |
1167 | */ | |
d8ac8971 | 1168 | rq_unpin_lock(rq, &rf); |
1019a359 | 1169 | push_dl_task(rq); |
d8ac8971 | 1170 | rq_repin_lock(rq, &rf); |
0aaafaab | 1171 | } |
1baca4ce | 1172 | #endif |
a649f237 | 1173 | |
aab03e05 | 1174 | unlock: |
eb580751 | 1175 | task_rq_unlock(rq, p, &rf); |
aab03e05 | 1176 | |
a649f237 PZ |
1177 | /* |
1178 | * This can free the task_struct, including this hrtimer, do not touch | |
1179 | * anything related to that after this. | |
1180 | */ | |
1181 | put_task_struct(p); | |
1182 | ||
aab03e05 DF |
1183 | return HRTIMER_NORESTART; |
1184 | } | |
1185 | ||
1186 | void init_dl_task_timer(struct sched_dl_entity *dl_se) | |
1187 | { | |
1188 | struct hrtimer *timer = &dl_se->dl_timer; | |
1189 | ||
d5096aa6 | 1190 | hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD); |
aab03e05 DF |
1191 | timer->function = dl_task_timer; |
1192 | } | |
1193 | ||
df8eac8c DBO |
1194 | /* |
1195 | * During the activation, CBS checks if it can reuse the current task's | |
1196 | * runtime and period. If the deadline of the task is in the past, CBS | |
1197 | * cannot use the runtime, and so it replenishes the task. This rule | |
1198 | * works fine for implicit deadline tasks (deadline == period), and the | |
1199 | * CBS was designed for implicit deadline tasks. However, a task with | |
c4969417 | 1200 | * constrained deadline (deadline < period) might be awakened after the |
df8eac8c DBO |
1201 | * deadline, but before the next period. In this case, replenishing the |
1202 | * task would allow it to run for runtime / deadline. As in this case | |
1203 | * deadline < period, CBS enables a task to run for more than the | |
1204 | * runtime / period. In a very loaded system, this can cause a domino | |
1205 | * effect, making other tasks miss their deadlines. | |
1206 | * | |
1207 | * To avoid this problem, in the activation of a constrained deadline | |
1208 | * task after the deadline but before the next period, throttle the | |
1209 | * task and set the replenishing timer to the begin of the next period, | |
1210 | * unless it is boosted. | |
1211 | */ | |
1212 | static inline void dl_check_constrained_dl(struct sched_dl_entity *dl_se) | |
1213 | { | |
1214 | struct task_struct *p = dl_task_of(dl_se); | |
1215 | struct rq *rq = rq_of_dl_rq(dl_rq_of_se(dl_se)); | |
1216 | ||
1217 | if (dl_time_before(dl_se->deadline, rq_clock(rq)) && | |
1218 | dl_time_before(rq_clock(rq), dl_next_period(dl_se))) { | |
2279f540 | 1219 | if (unlikely(is_dl_boosted(dl_se) || !start_dl_timer(p))) |
df8eac8c DBO |
1220 | return; |
1221 | dl_se->dl_throttled = 1; | |
ae83b56a XP |
1222 | if (dl_se->runtime > 0) |
1223 | dl_se->runtime = 0; | |
df8eac8c DBO |
1224 | } |
1225 | } | |
1226 | ||
aab03e05 | 1227 | static |
6fab5410 | 1228 | int dl_runtime_exceeded(struct sched_dl_entity *dl_se) |
aab03e05 | 1229 | { |
269ad801 | 1230 | return (dl_se->runtime <= 0); |
aab03e05 DF |
1231 | } |
1232 | ||
c52f14d3 | 1233 | /* |
6a9d623a VP |
1234 | * This function implements the GRUB accounting rule. According to the |
1235 | * GRUB reclaiming algorithm, the runtime is not decreased as "dq = -dt", | |
1236 | * but as "dq = -(max{u, (Umax - Uinact - Uextra)} / Umax) dt", | |
daec5798 LA |
1237 | * where u is the utilization of the task, Umax is the maximum reclaimable |
1238 | * utilization, Uinact is the (per-runqueue) inactive utilization, computed | |
1239 | * as the difference between the "total runqueue utilization" and the | |
6a9d623a | 1240 | * "runqueue active utilization", and Uextra is the (per runqueue) extra |
daec5798 | 1241 | * reclaimable utilization. |
6a9d623a VP |
1242 | * Since rq->dl.running_bw and rq->dl.this_bw contain utilizations multiplied |
1243 | * by 2^BW_SHIFT, the result has to be shifted right by BW_SHIFT. | |
1244 | * Since rq->dl.bw_ratio contains 1 / Umax multiplied by 2^RATIO_SHIFT, dl_bw | |
1245 | * is multiped by rq->dl.bw_ratio and shifted right by RATIO_SHIFT. | |
1246 | * Since delta is a 64 bit variable, to have an overflow its value should be | |
1247 | * larger than 2^(64 - 20 - 8), which is more than 64 seconds. So, overflow is | |
1248 | * not an issue here. | |
c52f14d3 | 1249 | */ |
3febfc8a | 1250 | static u64 grub_reclaim(u64 delta, struct rq *rq, struct sched_dl_entity *dl_se) |
c52f14d3 | 1251 | { |
9f0d1a50 | 1252 | u64 u_act; |
6a9d623a | 1253 | u64 u_inact = rq->dl.this_bw - rq->dl.running_bw; /* Utot - Uact */ |
c52f14d3 | 1254 | |
9f0d1a50 | 1255 | /* |
6a9d623a VP |
1256 | * Instead of computing max{u, (u_max - u_inact - u_extra)}, we |
1257 | * compare u_inact + u_extra with u_max - u, because u_inact + u_extra | |
1258 | * can be larger than u_max. So, u_max - u_inact - u_extra would be | |
1259 | * negative leading to wrong results. | |
9f0d1a50 | 1260 | */ |
6a9d623a VP |
1261 | if (u_inact + rq->dl.extra_bw > rq->dl.max_bw - dl_se->dl_bw) |
1262 | u_act = dl_se->dl_bw; | |
9f0d1a50 | 1263 | else |
6a9d623a | 1264 | u_act = rq->dl.max_bw - u_inact - rq->dl.extra_bw; |
9f0d1a50 | 1265 | |
6a9d623a | 1266 | u_act = (u_act * rq->dl.bw_ratio) >> RATIO_SHIFT; |
9f0d1a50 | 1267 | return (delta * u_act) >> BW_SHIFT; |
c52f14d3 LA |
1268 | } |
1269 | ||
aab03e05 DF |
1270 | /* |
1271 | * Update the current task's runtime statistics (provided it is still | |
1272 | * a -deadline task and has not been removed from the dl_rq). | |
1273 | */ | |
1274 | static void update_curr_dl(struct rq *rq) | |
1275 | { | |
1276 | struct task_struct *curr = rq->curr; | |
1277 | struct sched_dl_entity *dl_se = &curr->dl; | |
07881166 JL |
1278 | u64 delta_exec, scaled_delta_exec; |
1279 | int cpu = cpu_of(rq); | |
6fe0ce1e | 1280 | u64 now; |
aab03e05 DF |
1281 | |
1282 | if (!dl_task(curr) || !on_dl_rq(dl_se)) | |
1283 | return; | |
1284 | ||
1285 | /* | |
1286 | * Consumed budget is computed considering the time as | |
1287 | * observed by schedulable tasks (excluding time spent | |
1288 | * in hardirq context, etc.). Deadlines are instead | |
1289 | * computed using hard walltime. This seems to be the more | |
1290 | * natural solution, but the full ramifications of this | |
1291 | * approach need further study. | |
1292 | */ | |
6fe0ce1e WY |
1293 | now = rq_clock_task(rq); |
1294 | delta_exec = now - curr->se.exec_start; | |
48be3a67 PZ |
1295 | if (unlikely((s64)delta_exec <= 0)) { |
1296 | if (unlikely(dl_se->dl_yielded)) | |
1297 | goto throttle; | |
734ff2a7 | 1298 | return; |
48be3a67 | 1299 | } |
aab03e05 | 1300 | |
ceeadb83 YS |
1301 | schedstat_set(curr->stats.exec_max, |
1302 | max(curr->stats.exec_max, delta_exec)); | |
aab03e05 | 1303 | |
95fd58e8 YS |
1304 | trace_sched_stat_runtime(curr, delta_exec, 0); |
1305 | ||
5531ecff | 1306 | update_current_exec_runtime(curr, now, delta_exec); |
aab03e05 | 1307 | |
794a56eb JL |
1308 | if (dl_entity_is_special(dl_se)) |
1309 | return; | |
1310 | ||
07881166 JL |
1311 | /* |
1312 | * For tasks that participate in GRUB, we implement GRUB-PA: the | |
1313 | * spare reclaimed bandwidth is used to clock down frequency. | |
1314 | * | |
1315 | * For the others, we still need to scale reservation parameters | |
1316 | * according to current frequency and CPU maximum capacity. | |
1317 | */ | |
1318 | if (unlikely(dl_se->flags & SCHED_FLAG_RECLAIM)) { | |
1319 | scaled_delta_exec = grub_reclaim(delta_exec, | |
1320 | rq, | |
1321 | &curr->dl); | |
1322 | } else { | |
1323 | unsigned long scale_freq = arch_scale_freq_capacity(cpu); | |
8ec59c0f | 1324 | unsigned long scale_cpu = arch_scale_cpu_capacity(cpu); |
07881166 JL |
1325 | |
1326 | scaled_delta_exec = cap_scale(delta_exec, scale_freq); | |
1327 | scaled_delta_exec = cap_scale(scaled_delta_exec, scale_cpu); | |
1328 | } | |
1329 | ||
1330 | dl_se->runtime -= scaled_delta_exec; | |
48be3a67 PZ |
1331 | |
1332 | throttle: | |
1333 | if (dl_runtime_exceeded(dl_se) || dl_se->dl_yielded) { | |
1019a359 | 1334 | dl_se->dl_throttled = 1; |
34be3930 JL |
1335 | |
1336 | /* If requested, inform the user about runtime overruns. */ | |
1337 | if (dl_runtime_exceeded(dl_se) && | |
1338 | (dl_se->flags & SCHED_FLAG_DL_OVERRUN)) | |
1339 | dl_se->dl_overrun = 1; | |
1340 | ||
aab03e05 | 1341 | __dequeue_task_dl(rq, curr, 0); |
2279f540 | 1342 | if (unlikely(is_dl_boosted(dl_se) || !start_dl_timer(curr))) |
aab03e05 DF |
1343 | enqueue_task_dl(rq, curr, ENQUEUE_REPLENISH); |
1344 | ||
1345 | if (!is_leftmost(curr, &rq->dl)) | |
8875125e | 1346 | resched_curr(rq); |
aab03e05 | 1347 | } |
1724813d PZ |
1348 | |
1349 | /* | |
1350 | * Because -- for now -- we share the rt bandwidth, we need to | |
1351 | * account our runtime there too, otherwise actual rt tasks | |
1352 | * would be able to exceed the shared quota. | |
1353 | * | |
1354 | * Account to the root rt group for now. | |
1355 | * | |
1356 | * The solution we're working towards is having the RT groups scheduled | |
1357 | * using deadline servers -- however there's a few nasties to figure | |
1358 | * out before that can happen. | |
1359 | */ | |
1360 | if (rt_bandwidth_enabled()) { | |
1361 | struct rt_rq *rt_rq = &rq->rt; | |
1362 | ||
1363 | raw_spin_lock(&rt_rq->rt_runtime_lock); | |
1724813d PZ |
1364 | /* |
1365 | * We'll let actual RT tasks worry about the overflow here, we | |
faa59937 JL |
1366 | * have our own CBS to keep us inline; only account when RT |
1367 | * bandwidth is relevant. | |
1724813d | 1368 | */ |
faa59937 JL |
1369 | if (sched_rt_bandwidth_account(rt_rq)) |
1370 | rt_rq->rt_time += delta_exec; | |
1724813d PZ |
1371 | raw_spin_unlock(&rt_rq->rt_runtime_lock); |
1372 | } | |
aab03e05 DF |
1373 | } |
1374 | ||
209a0cbd LA |
1375 | static enum hrtimer_restart inactive_task_timer(struct hrtimer *timer) |
1376 | { | |
1377 | struct sched_dl_entity *dl_se = container_of(timer, | |
1378 | struct sched_dl_entity, | |
1379 | inactive_timer); | |
1380 | struct task_struct *p = dl_task_of(dl_se); | |
1381 | struct rq_flags rf; | |
1382 | struct rq *rq; | |
1383 | ||
1384 | rq = task_rq_lock(p, &rf); | |
1385 | ||
ecda2b66 JL |
1386 | sched_clock_tick(); |
1387 | update_rq_clock(rq); | |
1388 | ||
2f064a59 | 1389 | if (!dl_task(p) || READ_ONCE(p->__state) == TASK_DEAD) { |
387e3130 LA |
1390 | struct dl_bw *dl_b = dl_bw_of(task_cpu(p)); |
1391 | ||
2f064a59 | 1392 | if (READ_ONCE(p->__state) == TASK_DEAD && dl_se->dl_non_contending) { |
794a56eb JL |
1393 | sub_running_bw(&p->dl, dl_rq_of_se(&p->dl)); |
1394 | sub_rq_bw(&p->dl, dl_rq_of_se(&p->dl)); | |
209a0cbd LA |
1395 | dl_se->dl_non_contending = 0; |
1396 | } | |
387e3130 LA |
1397 | |
1398 | raw_spin_lock(&dl_b->lock); | |
8c0944ce | 1399 | __dl_sub(dl_b, p->dl.dl_bw, dl_bw_cpus(task_cpu(p))); |
387e3130 | 1400 | raw_spin_unlock(&dl_b->lock); |
209a0cbd LA |
1401 | __dl_clear_params(p); |
1402 | ||
1403 | goto unlock; | |
1404 | } | |
1405 | if (dl_se->dl_non_contending == 0) | |
1406 | goto unlock; | |
1407 | ||
794a56eb | 1408 | sub_running_bw(dl_se, &rq->dl); |
209a0cbd LA |
1409 | dl_se->dl_non_contending = 0; |
1410 | unlock: | |
1411 | task_rq_unlock(rq, p, &rf); | |
1412 | put_task_struct(p); | |
1413 | ||
1414 | return HRTIMER_NORESTART; | |
1415 | } | |
1416 | ||
1417 | void init_dl_inactive_task_timer(struct sched_dl_entity *dl_se) | |
1418 | { | |
1419 | struct hrtimer *timer = &dl_se->inactive_timer; | |
1420 | ||
850377a8 | 1421 | hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD); |
209a0cbd LA |
1422 | timer->function = inactive_task_timer; |
1423 | } | |
1424 | ||
f4478e7c DE |
1425 | #define __node_2_dle(node) \ |
1426 | rb_entry((node), struct sched_dl_entity, rb_node) | |
1427 | ||
1baca4ce JL |
1428 | #ifdef CONFIG_SMP |
1429 | ||
1baca4ce JL |
1430 | static void inc_dl_deadline(struct dl_rq *dl_rq, u64 deadline) |
1431 | { | |
1432 | struct rq *rq = rq_of_dl_rq(dl_rq); | |
1433 | ||
1434 | if (dl_rq->earliest_dl.curr == 0 || | |
1435 | dl_time_before(deadline, dl_rq->earliest_dl.curr)) { | |
b13772f8 PZ |
1436 | if (dl_rq->earliest_dl.curr == 0) |
1437 | cpupri_set(&rq->rd->cpupri, rq->cpu, CPUPRI_HIGHER); | |
1baca4ce | 1438 | dl_rq->earliest_dl.curr = deadline; |
d8206bb3 | 1439 | cpudl_set(&rq->rd->cpudl, rq->cpu, deadline); |
1baca4ce JL |
1440 | } |
1441 | } | |
1442 | ||
1443 | static void dec_dl_deadline(struct dl_rq *dl_rq, u64 deadline) | |
1444 | { | |
1445 | struct rq *rq = rq_of_dl_rq(dl_rq); | |
1446 | ||
1447 | /* | |
1448 | * Since we may have removed our earliest (and/or next earliest) | |
1449 | * task we must recompute them. | |
1450 | */ | |
1451 | if (!dl_rq->dl_nr_running) { | |
1452 | dl_rq->earliest_dl.curr = 0; | |
1453 | dl_rq->earliest_dl.next = 0; | |
d8206bb3 | 1454 | cpudl_clear(&rq->rd->cpudl, rq->cpu); |
b13772f8 | 1455 | cpupri_set(&rq->rd->cpupri, rq->cpu, rq->rt.highest_prio.curr); |
1baca4ce | 1456 | } else { |
f4478e7c DE |
1457 | struct rb_node *leftmost = rb_first_cached(&dl_rq->root); |
1458 | struct sched_dl_entity *entry = __node_2_dle(leftmost); | |
1baca4ce | 1459 | |
1baca4ce | 1460 | dl_rq->earliest_dl.curr = entry->deadline; |
d8206bb3 | 1461 | cpudl_set(&rq->rd->cpudl, rq->cpu, entry->deadline); |
1baca4ce JL |
1462 | } |
1463 | } | |
1464 | ||
1465 | #else | |
1466 | ||
1467 | static inline void inc_dl_deadline(struct dl_rq *dl_rq, u64 deadline) {} | |
1468 | static inline void dec_dl_deadline(struct dl_rq *dl_rq, u64 deadline) {} | |
1469 | ||
1470 | #endif /* CONFIG_SMP */ | |
1471 | ||
1472 | static inline | |
1473 | void inc_dl_tasks(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq) | |
1474 | { | |
1475 | int prio = dl_task_of(dl_se)->prio; | |
1476 | u64 deadline = dl_se->deadline; | |
1477 | ||
1478 | WARN_ON(!dl_prio(prio)); | |
1479 | dl_rq->dl_nr_running++; | |
72465447 | 1480 | add_nr_running(rq_of_dl_rq(dl_rq), 1); |
1baca4ce JL |
1481 | |
1482 | inc_dl_deadline(dl_rq, deadline); | |
1baca4ce JL |
1483 | } |
1484 | ||
1485 | static inline | |
1486 | void dec_dl_tasks(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq) | |
1487 | { | |
1488 | int prio = dl_task_of(dl_se)->prio; | |
1489 | ||
1490 | WARN_ON(!dl_prio(prio)); | |
1491 | WARN_ON(!dl_rq->dl_nr_running); | |
1492 | dl_rq->dl_nr_running--; | |
72465447 | 1493 | sub_nr_running(rq_of_dl_rq(dl_rq), 1); |
1baca4ce JL |
1494 | |
1495 | dec_dl_deadline(dl_rq, dl_se->deadline); | |
1baca4ce JL |
1496 | } |
1497 | ||
8ecca394 PZ |
1498 | static inline bool __dl_less(struct rb_node *a, const struct rb_node *b) |
1499 | { | |
1500 | return dl_time_before(__node_2_dle(a)->deadline, __node_2_dle(b)->deadline); | |
1501 | } | |
1502 | ||
b5eb4a5f YS |
1503 | static inline struct sched_statistics * |
1504 | __schedstats_from_dl_se(struct sched_dl_entity *dl_se) | |
1505 | { | |
1506 | return &dl_task_of(dl_se)->stats; | |
1507 | } | |
1508 | ||
1509 | static inline void | |
1510 | update_stats_wait_start_dl(struct dl_rq *dl_rq, struct sched_dl_entity *dl_se) | |
1511 | { | |
1512 | struct sched_statistics *stats; | |
1513 | ||
1514 | if (!schedstat_enabled()) | |
1515 | return; | |
1516 | ||
1517 | stats = __schedstats_from_dl_se(dl_se); | |
1518 | __update_stats_wait_start(rq_of_dl_rq(dl_rq), dl_task_of(dl_se), stats); | |
1519 | } | |
1520 | ||
1521 | static inline void | |
1522 | update_stats_wait_end_dl(struct dl_rq *dl_rq, struct sched_dl_entity *dl_se) | |
1523 | { | |
1524 | struct sched_statistics *stats; | |
1525 | ||
1526 | if (!schedstat_enabled()) | |
1527 | return; | |
1528 | ||
1529 | stats = __schedstats_from_dl_se(dl_se); | |
1530 | __update_stats_wait_end(rq_of_dl_rq(dl_rq), dl_task_of(dl_se), stats); | |
1531 | } | |
1532 | ||
1533 | static inline void | |
1534 | update_stats_enqueue_sleeper_dl(struct dl_rq *dl_rq, struct sched_dl_entity *dl_se) | |
1535 | { | |
1536 | struct sched_statistics *stats; | |
1537 | ||
1538 | if (!schedstat_enabled()) | |
1539 | return; | |
1540 | ||
1541 | stats = __schedstats_from_dl_se(dl_se); | |
1542 | __update_stats_enqueue_sleeper(rq_of_dl_rq(dl_rq), dl_task_of(dl_se), stats); | |
1543 | } | |
1544 | ||
1545 | static inline void | |
1546 | update_stats_enqueue_dl(struct dl_rq *dl_rq, struct sched_dl_entity *dl_se, | |
1547 | int flags) | |
1548 | { | |
1549 | if (!schedstat_enabled()) | |
1550 | return; | |
1551 | ||
1552 | if (flags & ENQUEUE_WAKEUP) | |
1553 | update_stats_enqueue_sleeper_dl(dl_rq, dl_se); | |
1554 | } | |
1555 | ||
1556 | static inline void | |
1557 | update_stats_dequeue_dl(struct dl_rq *dl_rq, struct sched_dl_entity *dl_se, | |
1558 | int flags) | |
1559 | { | |
1560 | struct task_struct *p = dl_task_of(dl_se); | |
1561 | ||
1562 | if (!schedstat_enabled()) | |
1563 | return; | |
1564 | ||
1565 | if ((flags & DEQUEUE_SLEEP)) { | |
1566 | unsigned int state; | |
1567 | ||
1568 | state = READ_ONCE(p->__state); | |
1569 | if (state & TASK_INTERRUPTIBLE) | |
1570 | __schedstat_set(p->stats.sleep_start, | |
1571 | rq_clock(rq_of_dl_rq(dl_rq))); | |
1572 | ||
1573 | if (state & TASK_UNINTERRUPTIBLE) | |
1574 | __schedstat_set(p->stats.block_start, | |
1575 | rq_clock(rq_of_dl_rq(dl_rq))); | |
1576 | } | |
1577 | } | |
1578 | ||
aab03e05 DF |
1579 | static void __enqueue_dl_entity(struct sched_dl_entity *dl_se) |
1580 | { | |
1581 | struct dl_rq *dl_rq = dl_rq_of_se(dl_se); | |
aab03e05 | 1582 | |
09348d75 | 1583 | WARN_ON_ONCE(!RB_EMPTY_NODE(&dl_se->rb_node)); |
aab03e05 | 1584 | |
8ecca394 | 1585 | rb_add_cached(&dl_se->rb_node, &dl_rq->root, __dl_less); |
aab03e05 | 1586 | |
1baca4ce | 1587 | inc_dl_tasks(dl_se, dl_rq); |
aab03e05 DF |
1588 | } |
1589 | ||
1590 | static void __dequeue_dl_entity(struct sched_dl_entity *dl_se) | |
1591 | { | |
1592 | struct dl_rq *dl_rq = dl_rq_of_se(dl_se); | |
1593 | ||
1594 | if (RB_EMPTY_NODE(&dl_se->rb_node)) | |
1595 | return; | |
1596 | ||
2161573e | 1597 | rb_erase_cached(&dl_se->rb_node, &dl_rq->root); |
8ecca394 | 1598 | |
aab03e05 DF |
1599 | RB_CLEAR_NODE(&dl_se->rb_node); |
1600 | ||
1baca4ce | 1601 | dec_dl_tasks(dl_se, dl_rq); |
aab03e05 DF |
1602 | } |
1603 | ||
1604 | static void | |
2279f540 | 1605 | enqueue_dl_entity(struct sched_dl_entity *dl_se, int flags) |
aab03e05 | 1606 | { |
09348d75 | 1607 | WARN_ON_ONCE(on_dl_rq(dl_se)); |
aab03e05 | 1608 | |
b5eb4a5f YS |
1609 | update_stats_enqueue_dl(dl_rq_of_se(dl_se), dl_se, flags); |
1610 | ||
aab03e05 DF |
1611 | /* |
1612 | * If this is a wakeup or a new instance, the scheduling | |
1613 | * parameters of the task might need updating. Otherwise, | |
1614 | * we want a replenishment of its runtime. | |
1615 | */ | |
e36d8677 | 1616 | if (flags & ENQUEUE_WAKEUP) { |
8fd27231 | 1617 | task_contending(dl_se, flags); |
2279f540 | 1618 | update_dl_entity(dl_se); |
e36d8677 | 1619 | } else if (flags & ENQUEUE_REPLENISH) { |
2279f540 | 1620 | replenish_dl_entity(dl_se); |
295d6d5e LA |
1621 | } else if ((flags & ENQUEUE_RESTORE) && |
1622 | dl_time_before(dl_se->deadline, | |
1623 | rq_clock(rq_of_dl_rq(dl_rq_of_se(dl_se))))) { | |
1624 | setup_new_dl_entity(dl_se); | |
e36d8677 | 1625 | } |
aab03e05 DF |
1626 | |
1627 | __enqueue_dl_entity(dl_se); | |
1628 | } | |
1629 | ||
1630 | static void dequeue_dl_entity(struct sched_dl_entity *dl_se) | |
1631 | { | |
1632 | __dequeue_dl_entity(dl_se); | |
1633 | } | |
1634 | ||
1635 | static void enqueue_task_dl(struct rq *rq, struct task_struct *p, int flags) | |
1636 | { | |
2279f540 | 1637 | if (is_dl_boosted(&p->dl)) { |
feff2e65 DBO |
1638 | /* |
1639 | * Because of delays in the detection of the overrun of a | |
1640 | * thread's runtime, it might be the case that a thread | |
1641 | * goes to sleep in a rt mutex with negative runtime. As | |
1642 | * a consequence, the thread will be throttled. | |
1643 | * | |
1644 | * While waiting for the mutex, this thread can also be | |
1645 | * boosted via PI, resulting in a thread that is throttled | |
1646 | * and boosted at the same time. | |
1647 | * | |
1648 | * In this case, the boost overrides the throttle. | |
1649 | */ | |
1650 | if (p->dl.dl_throttled) { | |
1651 | /* | |
1652 | * The replenish timer needs to be canceled. No | |
1653 | * problem if it fires concurrently: boosted threads | |
1654 | * are ignored in dl_task_timer(). | |
1655 | */ | |
1656 | hrtimer_try_to_cancel(&p->dl.dl_timer); | |
1657 | p->dl.dl_throttled = 0; | |
1658 | } | |
64be6f1f JL |
1659 | } else if (!dl_prio(p->normal_prio)) { |
1660 | /* | |
46fcc4b0 LS |
1661 | * Special case in which we have a !SCHED_DEADLINE task that is going |
1662 | * to be deboosted, but exceeds its runtime while doing so. No point in | |
1663 | * replenishing it, as it's going to return back to its original | |
1664 | * scheduling class after this. If it has been throttled, we need to | |
1665 | * clear the flag, otherwise the task may wake up as throttled after | |
1666 | * being boosted again with no means to replenish the runtime and clear | |
1667 | * the throttle. | |
64be6f1f | 1668 | */ |
46fcc4b0 | 1669 | p->dl.dl_throttled = 0; |
ddfc7103 JL |
1670 | if (!(flags & ENQUEUE_REPLENISH)) |
1671 | printk_deferred_once("sched: DL de-boosted task PID %d: REPLENISH flag missing\n", | |
1672 | task_pid_nr(p)); | |
1673 | ||
64be6f1f JL |
1674 | return; |
1675 | } | |
2d3d891d | 1676 | |
df8eac8c DBO |
1677 | /* |
1678 | * Check if a constrained deadline task was activated | |
1679 | * after the deadline but before the next period. | |
1680 | * If that is the case, the task will be throttled and | |
1681 | * the replenishment timer will be set to the next period. | |
1682 | */ | |
3effcb42 | 1683 | if (!p->dl.dl_throttled && !dl_is_implicit(&p->dl)) |
df8eac8c DBO |
1684 | dl_check_constrained_dl(&p->dl); |
1685 | ||
8fd27231 | 1686 | if (p->on_rq == TASK_ON_RQ_MIGRATING || flags & ENQUEUE_RESTORE) { |
794a56eb JL |
1687 | add_rq_bw(&p->dl, &rq->dl); |
1688 | add_running_bw(&p->dl, &rq->dl); | |
8fd27231 | 1689 | } |
e36d8677 | 1690 | |
aab03e05 | 1691 | /* |
e36d8677 | 1692 | * If p is throttled, we do not enqueue it. In fact, if it exhausted |
aab03e05 DF |
1693 | * its budget it needs a replenishment and, since it now is on |
1694 | * its rq, the bandwidth timer callback (which clearly has not | |
1695 | * run yet) will take care of this. | |
e36d8677 LA |
1696 | * However, the active utilization does not depend on the fact |
1697 | * that the task is on the runqueue or not (but depends on the | |
1698 | * task's state - in GRUB parlance, "inactive" vs "active contending"). | |
1699 | * In other words, even if a task is throttled its utilization must | |
1700 | * be counted in the active utilization; hence, we need to call | |
1701 | * add_running_bw(). | |
aab03e05 | 1702 | */ |
e36d8677 | 1703 | if (p->dl.dl_throttled && !(flags & ENQUEUE_REPLENISH)) { |
209a0cbd | 1704 | if (flags & ENQUEUE_WAKEUP) |
8fd27231 | 1705 | task_contending(&p->dl, flags); |
209a0cbd | 1706 | |
aab03e05 | 1707 | return; |
e36d8677 | 1708 | } |
aab03e05 | 1709 | |
b5eb4a5f YS |
1710 | check_schedstat_required(); |
1711 | update_stats_wait_start_dl(dl_rq_of_se(&p->dl), &p->dl); | |
1712 | ||
2279f540 | 1713 | enqueue_dl_entity(&p->dl, flags); |
1baca4ce | 1714 | |
4b53a341 | 1715 | if (!task_current(rq, p) && p->nr_cpus_allowed > 1) |
1baca4ce | 1716 | enqueue_pushable_dl_task(rq, p); |
aab03e05 DF |
1717 | } |
1718 | ||
1719 | static void __dequeue_task_dl(struct rq *rq, struct task_struct *p, int flags) | |
1720 | { | |
b5eb4a5f | 1721 | update_stats_dequeue_dl(&rq->dl, &p->dl, flags); |
aab03e05 | 1722 | dequeue_dl_entity(&p->dl); |
1baca4ce | 1723 | dequeue_pushable_dl_task(rq, p); |
aab03e05 DF |
1724 | } |
1725 | ||
1726 | static void dequeue_task_dl(struct rq *rq, struct task_struct *p, int flags) | |
1727 | { | |
1728 | update_curr_dl(rq); | |
1729 | __dequeue_task_dl(rq, p, flags); | |
e36d8677 | 1730 | |
8fd27231 | 1731 | if (p->on_rq == TASK_ON_RQ_MIGRATING || flags & DEQUEUE_SAVE) { |
794a56eb JL |
1732 | sub_running_bw(&p->dl, &rq->dl); |
1733 | sub_rq_bw(&p->dl, &rq->dl); | |
8fd27231 | 1734 | } |
e36d8677 LA |
1735 | |
1736 | /* | |
209a0cbd LA |
1737 | * This check allows to start the inactive timer (or to immediately |
1738 | * decrease the active utilization, if needed) in two cases: | |
e36d8677 LA |
1739 | * when the task blocks and when it is terminating |
1740 | * (p->state == TASK_DEAD). We can handle the two cases in the same | |
1741 | * way, because from GRUB's point of view the same thing is happening | |
1742 | * (the task moves from "active contending" to "active non contending" | |
1743 | * or "inactive") | |
1744 | */ | |
1745 | if (flags & DEQUEUE_SLEEP) | |
209a0cbd | 1746 | task_non_contending(p); |
aab03e05 DF |
1747 | } |
1748 | ||
1749 | /* | |
1750 | * Yield task semantic for -deadline tasks is: | |
1751 | * | |
1752 | * get off from the CPU until our next instance, with | |
1753 | * a new runtime. This is of little use now, since we | |
1754 | * don't have a bandwidth reclaiming mechanism. Anyway, | |
1755 | * bandwidth reclaiming is planned for the future, and | |
1756 | * yield_task_dl will indicate that some spare budget | |
1757 | * is available for other task instances to use it. | |
1758 | */ | |
1759 | static void yield_task_dl(struct rq *rq) | |
1760 | { | |
aab03e05 DF |
1761 | /* |
1762 | * We make the task go to sleep until its current deadline by | |
1763 | * forcing its runtime to zero. This way, update_curr_dl() stops | |
1764 | * it and the bandwidth timer will wake it up and will give it | |
5bfd126e | 1765 | * new scheduling parameters (thanks to dl_yielded=1). |
aab03e05 | 1766 | */ |
48be3a67 PZ |
1767 | rq->curr->dl.dl_yielded = 1; |
1768 | ||
6f1607f1 | 1769 | update_rq_clock(rq); |
aab03e05 | 1770 | update_curr_dl(rq); |
44fb085b WL |
1771 | /* |
1772 | * Tell update_rq_clock() that we've just updated, | |
1773 | * so we don't do microscopic update in schedule() | |
1774 | * and double the fastpath cost. | |
1775 | */ | |
adcc8da8 | 1776 | rq_clock_skip_update(rq); |
aab03e05 DF |
1777 | } |
1778 | ||
1baca4ce JL |
1779 | #ifdef CONFIG_SMP |
1780 | ||
973bee49 SX |
1781 | static inline bool dl_task_is_earliest_deadline(struct task_struct *p, |
1782 | struct rq *rq) | |
1783 | { | |
1784 | return (!rq->dl.dl_nr_running || | |
1785 | dl_time_before(p->dl.deadline, | |
1786 | rq->dl.earliest_dl.curr)); | |
1787 | } | |
1788 | ||
1baca4ce | 1789 | static int find_later_rq(struct task_struct *task); |
1baca4ce JL |
1790 | |
1791 | static int | |
3aef1551 | 1792 | select_task_rq_dl(struct task_struct *p, int cpu, int flags) |
1baca4ce JL |
1793 | { |
1794 | struct task_struct *curr; | |
b4118988 | 1795 | bool select_rq; |
1baca4ce JL |
1796 | struct rq *rq; |
1797 | ||
3aef1551 | 1798 | if (!(flags & WF_TTWU)) |
1baca4ce JL |
1799 | goto out; |
1800 | ||
1801 | rq = cpu_rq(cpu); | |
1802 | ||
1803 | rcu_read_lock(); | |
316c1608 | 1804 | curr = READ_ONCE(rq->curr); /* unlocked access */ |
1baca4ce JL |
1805 | |
1806 | /* | |
1807 | * If we are dealing with a -deadline task, we must | |
1808 | * decide where to wake it up. | |
1809 | * If it has a later deadline and the current task | |
1810 | * on this rq can't move (provided the waking task | |
1811 | * can!) we prefer to send it somewhere else. On the | |
1812 | * other hand, if it has a shorter deadline, we | |
1813 | * try to make it stay here, it might be important. | |
1814 | */ | |
b4118988 LA |
1815 | select_rq = unlikely(dl_task(curr)) && |
1816 | (curr->nr_cpus_allowed < 2 || | |
1817 | !dl_entity_preempt(&p->dl, &curr->dl)) && | |
1818 | p->nr_cpus_allowed > 1; | |
1819 | ||
1820 | /* | |
1821 | * Take the capacity of the CPU into account to | |
1822 | * ensure it fits the requirement of the task. | |
1823 | */ | |
740cf8a7 | 1824 | if (sched_asym_cpucap_active()) |
b4118988 LA |
1825 | select_rq |= !dl_task_fits_capacity(p, cpu); |
1826 | ||
1827 | if (select_rq) { | |
1baca4ce JL |
1828 | int target = find_later_rq(p); |
1829 | ||
9d514262 | 1830 | if (target != -1 && |
973bee49 | 1831 | dl_task_is_earliest_deadline(p, cpu_rq(target))) |
1baca4ce JL |
1832 | cpu = target; |
1833 | } | |
1834 | rcu_read_unlock(); | |
1835 | ||
1836 | out: | |
1837 | return cpu; | |
1838 | } | |
1839 | ||
1327237a | 1840 | static void migrate_task_rq_dl(struct task_struct *p, int new_cpu __maybe_unused) |
209a0cbd | 1841 | { |
2679a837 | 1842 | struct rq_flags rf; |
209a0cbd LA |
1843 | struct rq *rq; |
1844 | ||
2f064a59 | 1845 | if (READ_ONCE(p->__state) != TASK_WAKING) |
209a0cbd LA |
1846 | return; |
1847 | ||
1848 | rq = task_rq(p); | |
1849 | /* | |
1850 | * Since p->state == TASK_WAKING, set_task_cpu() has been called | |
1851 | * from try_to_wake_up(). Hence, p->pi_lock is locked, but | |
1852 | * rq->lock is not... So, lock it | |
1853 | */ | |
2679a837 | 1854 | rq_lock(rq, &rf); |
8fd27231 | 1855 | if (p->dl.dl_non_contending) { |
b4da13aa | 1856 | update_rq_clock(rq); |
794a56eb | 1857 | sub_running_bw(&p->dl, &rq->dl); |
8fd27231 LA |
1858 | p->dl.dl_non_contending = 0; |
1859 | /* | |
1860 | * If the timer handler is currently running and the | |
3b03706f | 1861 | * timer cannot be canceled, inactive_task_timer() |
8fd27231 LA |
1862 | * will see that dl_not_contending is not set, and |
1863 | * will not touch the rq's active utilization, | |
1864 | * so we are still safe. | |
1865 | */ | |
1866 | if (hrtimer_try_to_cancel(&p->dl.inactive_timer) == 1) | |
1867 | put_task_struct(p); | |
1868 | } | |
794a56eb | 1869 | sub_rq_bw(&p->dl, &rq->dl); |
2679a837 | 1870 | rq_unlock(rq, &rf); |
209a0cbd LA |
1871 | } |
1872 | ||
1baca4ce JL |
1873 | static void check_preempt_equal_dl(struct rq *rq, struct task_struct *p) |
1874 | { | |
1875 | /* | |
1876 | * Current can't be migrated, useless to reschedule, | |
1877 | * let's hope p can move out. | |
1878 | */ | |
4b53a341 | 1879 | if (rq->curr->nr_cpus_allowed == 1 || |
3261ed0b | 1880 | !cpudl_find(&rq->rd->cpudl, rq->curr, NULL)) |
1baca4ce JL |
1881 | return; |
1882 | ||
1883 | /* | |
1884 | * p is migratable, so let's not schedule it and | |
1885 | * see if it is pushed or pulled somewhere else. | |
1886 | */ | |
4b53a341 | 1887 | if (p->nr_cpus_allowed != 1 && |
3261ed0b | 1888 | cpudl_find(&rq->rd->cpudl, p, NULL)) |
1baca4ce JL |
1889 | return; |
1890 | ||
8875125e | 1891 | resched_curr(rq); |
1baca4ce JL |
1892 | } |
1893 | ||
6e2df058 PZ |
1894 | static int balance_dl(struct rq *rq, struct task_struct *p, struct rq_flags *rf) |
1895 | { | |
1896 | if (!on_dl_rq(&p->dl) && need_pull_dl_task(rq, p)) { | |
1897 | /* | |
1898 | * This is OK, because current is on_cpu, which avoids it being | |
1899 | * picked for load-balance and preemption/IRQs are still | |
1900 | * disabled avoiding further scheduler activity on it and we've | |
1901 | * not yet started the picking loop. | |
1902 | */ | |
1903 | rq_unpin_lock(rq, rf); | |
1904 | pull_dl_task(rq); | |
1905 | rq_repin_lock(rq, rf); | |
1906 | } | |
1907 | ||
1908 | return sched_stop_runnable(rq) || sched_dl_runnable(rq); | |
1909 | } | |
1baca4ce JL |
1910 | #endif /* CONFIG_SMP */ |
1911 | ||
aab03e05 DF |
1912 | /* |
1913 | * Only called when both the current and waking task are -deadline | |
1914 | * tasks. | |
1915 | */ | |
e23edc86 | 1916 | static void wakeup_preempt_dl(struct rq *rq, struct task_struct *p, |
aab03e05 DF |
1917 | int flags) |
1918 | { | |
1baca4ce | 1919 | if (dl_entity_preempt(&p->dl, &rq->curr->dl)) { |
8875125e | 1920 | resched_curr(rq); |
1baca4ce JL |
1921 | return; |
1922 | } | |
1923 | ||
1924 | #ifdef CONFIG_SMP | |
1925 | /* | |
1926 | * In the unlikely case current and p have the same deadline | |
1927 | * let us try to decide what's the best thing to do... | |
1928 | */ | |
332ac17e DF |
1929 | if ((p->dl.deadline == rq->curr->dl.deadline) && |
1930 | !test_tsk_need_resched(rq->curr)) | |
1baca4ce JL |
1931 | check_preempt_equal_dl(rq, p); |
1932 | #endif /* CONFIG_SMP */ | |
aab03e05 DF |
1933 | } |
1934 | ||
1935 | #ifdef CONFIG_SCHED_HRTICK | |
1936 | static void start_hrtick_dl(struct rq *rq, struct task_struct *p) | |
1937 | { | |
177ef2a6 | 1938 | hrtick_start(rq, p->dl.runtime); |
aab03e05 | 1939 | } |
36ce9881 WL |
1940 | #else /* !CONFIG_SCHED_HRTICK */ |
1941 | static void start_hrtick_dl(struct rq *rq, struct task_struct *p) | |
1942 | { | |
1943 | } | |
aab03e05 DF |
1944 | #endif |
1945 | ||
a0e813f2 | 1946 | static void set_next_task_dl(struct rq *rq, struct task_struct *p, bool first) |
ff1cdc94 | 1947 | { |
b5eb4a5f YS |
1948 | struct sched_dl_entity *dl_se = &p->dl; |
1949 | struct dl_rq *dl_rq = &rq->dl; | |
1950 | ||
ff1cdc94 | 1951 | p->se.exec_start = rq_clock_task(rq); |
b5eb4a5f YS |
1952 | if (on_dl_rq(&p->dl)) |
1953 | update_stats_wait_end_dl(dl_rq, dl_se); | |
ff1cdc94 MS |
1954 | |
1955 | /* You can't push away the running task */ | |
1956 | dequeue_pushable_dl_task(rq, p); | |
f95d4eae | 1957 | |
a0e813f2 PZ |
1958 | if (!first) |
1959 | return; | |
1960 | ||
e0ee463c | 1961 | if (hrtick_enabled_dl(rq)) |
f95d4eae PZ |
1962 | start_hrtick_dl(rq, p); |
1963 | ||
1964 | if (rq->curr->sched_class != &dl_sched_class) | |
1965 | update_dl_rq_load_avg(rq_clock_pelt(rq), rq, 0); | |
1966 | ||
1967 | deadline_queue_push_tasks(rq); | |
ff1cdc94 MS |
1968 | } |
1969 | ||
821aecd0 | 1970 | static struct sched_dl_entity *pick_next_dl_entity(struct dl_rq *dl_rq) |
aab03e05 | 1971 | { |
2161573e | 1972 | struct rb_node *left = rb_first_cached(&dl_rq->root); |
aab03e05 DF |
1973 | |
1974 | if (!left) | |
1975 | return NULL; | |
1976 | ||
f4478e7c | 1977 | return __node_2_dle(left); |
aab03e05 DF |
1978 | } |
1979 | ||
21f56ffe | 1980 | static struct task_struct *pick_task_dl(struct rq *rq) |
aab03e05 DF |
1981 | { |
1982 | struct sched_dl_entity *dl_se; | |
6e2df058 | 1983 | struct dl_rq *dl_rq = &rq->dl; |
aab03e05 | 1984 | struct task_struct *p; |
aab03e05 | 1985 | |
6e2df058 | 1986 | if (!sched_dl_runnable(rq)) |
aab03e05 DF |
1987 | return NULL; |
1988 | ||
821aecd0 | 1989 | dl_se = pick_next_dl_entity(dl_rq); |
09348d75 | 1990 | WARN_ON_ONCE(!dl_se); |
aab03e05 | 1991 | p = dl_task_of(dl_se); |
21f56ffe PZ |
1992 | |
1993 | return p; | |
1994 | } | |
1995 | ||
1996 | static struct task_struct *pick_next_task_dl(struct rq *rq) | |
1997 | { | |
1998 | struct task_struct *p; | |
1999 | ||
2000 | p = pick_task_dl(rq); | |
2001 | if (p) | |
2002 | set_next_task_dl(rq, p, true); | |
2003 | ||
aab03e05 DF |
2004 | return p; |
2005 | } | |
2006 | ||
6e2df058 | 2007 | static void put_prev_task_dl(struct rq *rq, struct task_struct *p) |
aab03e05 | 2008 | { |
b5eb4a5f YS |
2009 | struct sched_dl_entity *dl_se = &p->dl; |
2010 | struct dl_rq *dl_rq = &rq->dl; | |
2011 | ||
2012 | if (on_dl_rq(&p->dl)) | |
2013 | update_stats_wait_start_dl(dl_rq, dl_se); | |
2014 | ||
aab03e05 | 2015 | update_curr_dl(rq); |
1baca4ce | 2016 | |
23127296 | 2017 | update_dl_rq_load_avg(rq_clock_pelt(rq), rq, 1); |
4b53a341 | 2018 | if (on_dl_rq(&p->dl) && p->nr_cpus_allowed > 1) |
1baca4ce | 2019 | enqueue_pushable_dl_task(rq, p); |
aab03e05 DF |
2020 | } |
2021 | ||
d84b3131 FW |
2022 | /* |
2023 | * scheduler tick hitting a task of our scheduling class. | |
2024 | * | |
2025 | * NOTE: This function can be called remotely by the tick offload that | |
2026 | * goes along full dynticks. Therefore no local assumption can be made | |
2027 | * and everything must be accessed through the @rq and @curr passed in | |
2028 | * parameters. | |
2029 | */ | |
aab03e05 DF |
2030 | static void task_tick_dl(struct rq *rq, struct task_struct *p, int queued) |
2031 | { | |
2032 | update_curr_dl(rq); | |
2033 | ||
23127296 | 2034 | update_dl_rq_load_avg(rq_clock_pelt(rq), rq, 1); |
a7bebf48 WL |
2035 | /* |
2036 | * Even when we have runtime, update_curr_dl() might have resulted in us | |
2037 | * not being the leftmost task anymore. In that case NEED_RESCHED will | |
2038 | * be set and schedule() will start a new hrtick for the next task. | |
2039 | */ | |
e0ee463c | 2040 | if (hrtick_enabled_dl(rq) && queued && p->dl.runtime > 0 && |
a7bebf48 | 2041 | is_leftmost(p, &rq->dl)) |
aab03e05 | 2042 | start_hrtick_dl(rq, p); |
aab03e05 DF |
2043 | } |
2044 | ||
2045 | static void task_fork_dl(struct task_struct *p) | |
2046 | { | |
2047 | /* | |
2048 | * SCHED_DEADLINE tasks cannot fork and this is achieved through | |
2049 | * sched_fork() | |
2050 | */ | |
2051 | } | |
2052 | ||
1baca4ce JL |
2053 | #ifdef CONFIG_SMP |
2054 | ||
2055 | /* Only try algorithms three times */ | |
2056 | #define DL_MAX_TRIES 3 | |
2057 | ||
2058 | static int pick_dl_task(struct rq *rq, struct task_struct *p, int cpu) | |
2059 | { | |
0b9d46fc | 2060 | if (!task_on_cpu(rq, p) && |
95158a89 | 2061 | cpumask_test_cpu(cpu, &p->cpus_mask)) |
1baca4ce | 2062 | return 1; |
1baca4ce JL |
2063 | return 0; |
2064 | } | |
2065 | ||
8b5e770e WL |
2066 | /* |
2067 | * Return the earliest pushable rq's task, which is suitable to be executed | |
2068 | * on the CPU, NULL otherwise: | |
2069 | */ | |
2070 | static struct task_struct *pick_earliest_pushable_dl_task(struct rq *rq, int cpu) | |
2071 | { | |
8b5e770e | 2072 | struct task_struct *p = NULL; |
f4478e7c | 2073 | struct rb_node *next_node; |
8b5e770e WL |
2074 | |
2075 | if (!has_pushable_dl_tasks(rq)) | |
2076 | return NULL; | |
2077 | ||
f4478e7c DE |
2078 | next_node = rb_first_cached(&rq->dl.pushable_dl_tasks_root); |
2079 | ||
8b5e770e WL |
2080 | next_node: |
2081 | if (next_node) { | |
f4478e7c | 2082 | p = __node_2_pdl(next_node); |
8b5e770e WL |
2083 | |
2084 | if (pick_dl_task(rq, p, cpu)) | |
2085 | return p; | |
2086 | ||
2087 | next_node = rb_next(next_node); | |
2088 | goto next_node; | |
2089 | } | |
2090 | ||
2091 | return NULL; | |
2092 | } | |
2093 | ||
1baca4ce JL |
2094 | static DEFINE_PER_CPU(cpumask_var_t, local_cpu_mask_dl); |
2095 | ||
2096 | static int find_later_rq(struct task_struct *task) | |
2097 | { | |
2098 | struct sched_domain *sd; | |
4ba29684 | 2099 | struct cpumask *later_mask = this_cpu_cpumask_var_ptr(local_cpu_mask_dl); |
1baca4ce | 2100 | int this_cpu = smp_processor_id(); |
b18c3ca1 | 2101 | int cpu = task_cpu(task); |
1baca4ce JL |
2102 | |
2103 | /* Make sure the mask is initialized first */ | |
2104 | if (unlikely(!later_mask)) | |
2105 | return -1; | |
2106 | ||
4b53a341 | 2107 | if (task->nr_cpus_allowed == 1) |
1baca4ce JL |
2108 | return -1; |
2109 | ||
91ec6778 JL |
2110 | /* |
2111 | * We have to consider system topology and task affinity | |
97fb7a0a | 2112 | * first, then we can look for a suitable CPU. |
91ec6778 | 2113 | */ |
3261ed0b | 2114 | if (!cpudl_find(&task_rq(task)->rd->cpudl, task, later_mask)) |
1baca4ce JL |
2115 | return -1; |
2116 | ||
2117 | /* | |
b18c3ca1 BP |
2118 | * If we are here, some targets have been found, including |
2119 | * the most suitable which is, among the runqueues where the | |
2120 | * current tasks have later deadlines than the task's one, the | |
2121 | * rq with the latest possible one. | |
1baca4ce JL |
2122 | * |
2123 | * Now we check how well this matches with task's | |
2124 | * affinity and system topology. | |
2125 | * | |
97fb7a0a | 2126 | * The last CPU where the task run is our first |
1baca4ce JL |
2127 | * guess, since it is most likely cache-hot there. |
2128 | */ | |
2129 | if (cpumask_test_cpu(cpu, later_mask)) | |
2130 | return cpu; | |
2131 | /* | |
2132 | * Check if this_cpu is to be skipped (i.e., it is | |
2133 | * not in the mask) or not. | |
2134 | */ | |
2135 | if (!cpumask_test_cpu(this_cpu, later_mask)) | |
2136 | this_cpu = -1; | |
2137 | ||
2138 | rcu_read_lock(); | |
2139 | for_each_domain(cpu, sd) { | |
2140 | if (sd->flags & SD_WAKE_AFFINE) { | |
b18c3ca1 | 2141 | int best_cpu; |
1baca4ce JL |
2142 | |
2143 | /* | |
2144 | * If possible, preempting this_cpu is | |
2145 | * cheaper than migrating. | |
2146 | */ | |
2147 | if (this_cpu != -1 && | |
2148 | cpumask_test_cpu(this_cpu, sched_domain_span(sd))) { | |
2149 | rcu_read_unlock(); | |
2150 | return this_cpu; | |
2151 | } | |
2152 | ||
14e292f8 PZ |
2153 | best_cpu = cpumask_any_and_distribute(later_mask, |
2154 | sched_domain_span(sd)); | |
1baca4ce | 2155 | /* |
97fb7a0a | 2156 | * Last chance: if a CPU being in both later_mask |
b18c3ca1 | 2157 | * and current sd span is valid, that becomes our |
97fb7a0a | 2158 | * choice. Of course, the latest possible CPU is |
b18c3ca1 | 2159 | * already under consideration through later_mask. |
1baca4ce | 2160 | */ |
b18c3ca1 | 2161 | if (best_cpu < nr_cpu_ids) { |
1baca4ce JL |
2162 | rcu_read_unlock(); |
2163 | return best_cpu; | |
2164 | } | |
2165 | } | |
2166 | } | |
2167 | rcu_read_unlock(); | |
2168 | ||
2169 | /* | |
2170 | * At this point, all our guesses failed, we just return | |
2171 | * 'something', and let the caller sort the things out. | |
2172 | */ | |
2173 | if (this_cpu != -1) | |
2174 | return this_cpu; | |
2175 | ||
14e292f8 | 2176 | cpu = cpumask_any_distribute(later_mask); |
1baca4ce JL |
2177 | if (cpu < nr_cpu_ids) |
2178 | return cpu; | |
2179 | ||
2180 | return -1; | |
2181 | } | |
2182 | ||
2183 | /* Locks the rq it finds */ | |
2184 | static struct rq *find_lock_later_rq(struct task_struct *task, struct rq *rq) | |
2185 | { | |
2186 | struct rq *later_rq = NULL; | |
2187 | int tries; | |
2188 | int cpu; | |
2189 | ||
2190 | for (tries = 0; tries < DL_MAX_TRIES; tries++) { | |
2191 | cpu = find_later_rq(task); | |
2192 | ||
2193 | if ((cpu == -1) || (cpu == rq->cpu)) | |
2194 | break; | |
2195 | ||
2196 | later_rq = cpu_rq(cpu); | |
2197 | ||
973bee49 | 2198 | if (!dl_task_is_earliest_deadline(task, later_rq)) { |
9d514262 WL |
2199 | /* |
2200 | * Target rq has tasks of equal or earlier deadline, | |
2201 | * retrying does not release any lock and is unlikely | |
2202 | * to yield a different result. | |
2203 | */ | |
2204 | later_rq = NULL; | |
2205 | break; | |
2206 | } | |
2207 | ||
1baca4ce JL |
2208 | /* Retry if something changed. */ |
2209 | if (double_lock_balance(rq, later_rq)) { | |
2210 | if (unlikely(task_rq(task) != rq || | |
95158a89 | 2211 | !cpumask_test_cpu(later_rq->cpu, &task->cpus_mask) || |
0b9d46fc | 2212 | task_on_cpu(rq, task) || |
13b5ab02 | 2213 | !dl_task(task) || |
feffe5bb | 2214 | is_migration_disabled(task) || |
da0c1e65 | 2215 | !task_on_rq_queued(task))) { |
1baca4ce JL |
2216 | double_unlock_balance(rq, later_rq); |
2217 | later_rq = NULL; | |
2218 | break; | |
2219 | } | |
2220 | } | |
2221 | ||
2222 | /* | |
2223 | * If the rq we found has no -deadline task, or | |
2224 | * its earliest one has a later deadline than our | |
2225 | * task, the rq is a good one. | |
2226 | */ | |
973bee49 | 2227 | if (dl_task_is_earliest_deadline(task, later_rq)) |
1baca4ce JL |
2228 | break; |
2229 | ||
2230 | /* Otherwise we try again. */ | |
2231 | double_unlock_balance(rq, later_rq); | |
2232 | later_rq = NULL; | |
2233 | } | |
2234 | ||
2235 | return later_rq; | |
2236 | } | |
2237 | ||
2238 | static struct task_struct *pick_next_pushable_dl_task(struct rq *rq) | |
2239 | { | |
2240 | struct task_struct *p; | |
2241 | ||
2242 | if (!has_pushable_dl_tasks(rq)) | |
2243 | return NULL; | |
2244 | ||
f4478e7c | 2245 | p = __node_2_pdl(rb_first_cached(&rq->dl.pushable_dl_tasks_root)); |
1baca4ce | 2246 | |
09348d75 IM |
2247 | WARN_ON_ONCE(rq->cpu != task_cpu(p)); |
2248 | WARN_ON_ONCE(task_current(rq, p)); | |
2249 | WARN_ON_ONCE(p->nr_cpus_allowed <= 1); | |
1baca4ce | 2250 | |
09348d75 IM |
2251 | WARN_ON_ONCE(!task_on_rq_queued(p)); |
2252 | WARN_ON_ONCE(!dl_task(p)); | |
1baca4ce JL |
2253 | |
2254 | return p; | |
2255 | } | |
2256 | ||
2257 | /* | |
2258 | * See if the non running -deadline tasks on this rq | |
2259 | * can be sent to some other CPU where they can preempt | |
2260 | * and start executing. | |
2261 | */ | |
2262 | static int push_dl_task(struct rq *rq) | |
2263 | { | |
2264 | struct task_struct *next_task; | |
2265 | struct rq *later_rq; | |
c51b8ab5 | 2266 | int ret = 0; |
1baca4ce | 2267 | |
1baca4ce JL |
2268 | next_task = pick_next_pushable_dl_task(rq); |
2269 | if (!next_task) | |
2270 | return 0; | |
2271 | ||
2272 | retry: | |
1baca4ce JL |
2273 | /* |
2274 | * If next_task preempts rq->curr, and rq->curr | |
2275 | * can move away, it makes sense to just reschedule | |
2276 | * without going further in pushing next_task. | |
2277 | */ | |
2278 | if (dl_task(rq->curr) && | |
2279 | dl_time_before(next_task->dl.deadline, rq->curr->dl.deadline) && | |
4b53a341 | 2280 | rq->curr->nr_cpus_allowed > 1) { |
8875125e | 2281 | resched_curr(rq); |
1baca4ce JL |
2282 | return 0; |
2283 | } | |
2284 | ||
49bef33e VS |
2285 | if (is_migration_disabled(next_task)) |
2286 | return 0; | |
2287 | ||
2288 | if (WARN_ON(next_task == rq->curr)) | |
2289 | return 0; | |
2290 | ||
1baca4ce JL |
2291 | /* We might release rq lock */ |
2292 | get_task_struct(next_task); | |
2293 | ||
2294 | /* Will lock the rq it'll find */ | |
2295 | later_rq = find_lock_later_rq(next_task, rq); | |
2296 | if (!later_rq) { | |
2297 | struct task_struct *task; | |
2298 | ||
2299 | /* | |
2300 | * We must check all this again, since | |
2301 | * find_lock_later_rq releases rq->lock and it is | |
2302 | * then possible that next_task has migrated. | |
2303 | */ | |
2304 | task = pick_next_pushable_dl_task(rq); | |
a776b968 | 2305 | if (task == next_task) { |
1baca4ce JL |
2306 | /* |
2307 | * The task is still there. We don't try | |
97fb7a0a | 2308 | * again, some other CPU will pull it when ready. |
1baca4ce | 2309 | */ |
1baca4ce JL |
2310 | goto out; |
2311 | } | |
2312 | ||
2313 | if (!task) | |
2314 | /* No more tasks */ | |
2315 | goto out; | |
2316 | ||
2317 | put_task_struct(next_task); | |
2318 | next_task = task; | |
2319 | goto retry; | |
2320 | } | |
2321 | ||
2322 | deactivate_task(rq, next_task, 0); | |
2323 | set_task_cpu(next_task, later_rq->cpu); | |
734387ec | 2324 | activate_task(later_rq, next_task, 0); |
c51b8ab5 | 2325 | ret = 1; |
1baca4ce | 2326 | |
8875125e | 2327 | resched_curr(later_rq); |
1baca4ce JL |
2328 | |
2329 | double_unlock_balance(rq, later_rq); | |
2330 | ||
2331 | out: | |
2332 | put_task_struct(next_task); | |
2333 | ||
c51b8ab5 | 2334 | return ret; |
1baca4ce JL |
2335 | } |
2336 | ||
2337 | static void push_dl_tasks(struct rq *rq) | |
2338 | { | |
4ffa08ed | 2339 | /* push_dl_task() will return true if it moved a -deadline task */ |
1baca4ce JL |
2340 | while (push_dl_task(rq)) |
2341 | ; | |
aab03e05 DF |
2342 | } |
2343 | ||
0ea60c20 | 2344 | static void pull_dl_task(struct rq *this_rq) |
1baca4ce | 2345 | { |
0ea60c20 | 2346 | int this_cpu = this_rq->cpu, cpu; |
a7c81556 | 2347 | struct task_struct *p, *push_task; |
0ea60c20 | 2348 | bool resched = false; |
1baca4ce JL |
2349 | struct rq *src_rq; |
2350 | u64 dmin = LONG_MAX; | |
2351 | ||
2352 | if (likely(!dl_overloaded(this_rq))) | |
0ea60c20 | 2353 | return; |
1baca4ce JL |
2354 | |
2355 | /* | |
2356 | * Match the barrier from dl_set_overloaded; this guarantees that if we | |
2357 | * see overloaded we must also see the dlo_mask bit. | |
2358 | */ | |
2359 | smp_rmb(); | |
2360 | ||
2361 | for_each_cpu(cpu, this_rq->rd->dlo_mask) { | |
2362 | if (this_cpu == cpu) | |
2363 | continue; | |
2364 | ||
2365 | src_rq = cpu_rq(cpu); | |
2366 | ||
2367 | /* | |
2368 | * It looks racy, abd it is! However, as in sched_rt.c, | |
2369 | * we are fine with this. | |
2370 | */ | |
2371 | if (this_rq->dl.dl_nr_running && | |
2372 | dl_time_before(this_rq->dl.earliest_dl.curr, | |
2373 | src_rq->dl.earliest_dl.next)) | |
2374 | continue; | |
2375 | ||
2376 | /* Might drop this_rq->lock */ | |
a7c81556 | 2377 | push_task = NULL; |
1baca4ce JL |
2378 | double_lock_balance(this_rq, src_rq); |
2379 | ||
2380 | /* | |
2381 | * If there are no more pullable tasks on the | |
2382 | * rq, we're done with it. | |
2383 | */ | |
2384 | if (src_rq->dl.dl_nr_running <= 1) | |
2385 | goto skip; | |
2386 | ||
8b5e770e | 2387 | p = pick_earliest_pushable_dl_task(src_rq, this_cpu); |
1baca4ce JL |
2388 | |
2389 | /* | |
2390 | * We found a task to be pulled if: | |
2391 | * - it preempts our current (if there's one), | |
2392 | * - it will preempt the last one we pulled (if any). | |
2393 | */ | |
2394 | if (p && dl_time_before(p->dl.deadline, dmin) && | |
973bee49 | 2395 | dl_task_is_earliest_deadline(p, this_rq)) { |
1baca4ce | 2396 | WARN_ON(p == src_rq->curr); |
da0c1e65 | 2397 | WARN_ON(!task_on_rq_queued(p)); |
1baca4ce JL |
2398 | |
2399 | /* | |
2400 | * Then we pull iff p has actually an earlier | |
2401 | * deadline than the current task of its runqueue. | |
2402 | */ | |
2403 | if (dl_time_before(p->dl.deadline, | |
2404 | src_rq->curr->dl.deadline)) | |
2405 | goto skip; | |
2406 | ||
a7c81556 PZ |
2407 | if (is_migration_disabled(p)) { |
2408 | push_task = get_push_task(src_rq); | |
2409 | } else { | |
2410 | deactivate_task(src_rq, p, 0); | |
2411 | set_task_cpu(p, this_cpu); | |
2412 | activate_task(this_rq, p, 0); | |
2413 | dmin = p->dl.deadline; | |
2414 | resched = true; | |
2415 | } | |
1baca4ce JL |
2416 | |
2417 | /* Is there any other task even earlier? */ | |
2418 | } | |
2419 | skip: | |
2420 | double_unlock_balance(this_rq, src_rq); | |
a7c81556 PZ |
2421 | |
2422 | if (push_task) { | |
5cb9eaa3 | 2423 | raw_spin_rq_unlock(this_rq); |
a7c81556 PZ |
2424 | stop_one_cpu_nowait(src_rq->cpu, push_cpu_stop, |
2425 | push_task, &src_rq->push_work); | |
5cb9eaa3 | 2426 | raw_spin_rq_lock(this_rq); |
a7c81556 | 2427 | } |
1baca4ce JL |
2428 | } |
2429 | ||
0ea60c20 PZ |
2430 | if (resched) |
2431 | resched_curr(this_rq); | |
1baca4ce JL |
2432 | } |
2433 | ||
2434 | /* | |
2435 | * Since the task is not running and a reschedule is not going to happen | |
2436 | * anytime soon on its runqueue, we try pushing it away now. | |
2437 | */ | |
2438 | static void task_woken_dl(struct rq *rq, struct task_struct *p) | |
2439 | { | |
0b9d46fc | 2440 | if (!task_on_cpu(rq, p) && |
1baca4ce | 2441 | !test_tsk_need_resched(rq->curr) && |
4b53a341 | 2442 | p->nr_cpus_allowed > 1 && |
1baca4ce | 2443 | dl_task(rq->curr) && |
4b53a341 | 2444 | (rq->curr->nr_cpus_allowed < 2 || |
6b0a563f | 2445 | !dl_entity_preempt(&p->dl, &rq->curr->dl))) { |
1baca4ce JL |
2446 | push_dl_tasks(rq); |
2447 | } | |
2448 | } | |
2449 | ||
2450 | static void set_cpus_allowed_dl(struct task_struct *p, | |
713a2e21 | 2451 | struct affinity_context *ctx) |
1baca4ce | 2452 | { |
7f51412a | 2453 | struct root_domain *src_rd; |
6c37067e | 2454 | struct rq *rq; |
1baca4ce | 2455 | |
09348d75 | 2456 | WARN_ON_ONCE(!dl_task(p)); |
1baca4ce | 2457 | |
7f51412a JL |
2458 | rq = task_rq(p); |
2459 | src_rd = rq->rd; | |
2460 | /* | |
2461 | * Migrating a SCHED_DEADLINE task between exclusive | |
2462 | * cpusets (different root_domains) entails a bandwidth | |
2463 | * update. We already made space for us in the destination | |
2464 | * domain (see cpuset_can_attach()). | |
2465 | */ | |
713a2e21 | 2466 | if (!cpumask_intersects(src_rd->span, ctx->new_mask)) { |
7f51412a JL |
2467 | struct dl_bw *src_dl_b; |
2468 | ||
2469 | src_dl_b = dl_bw_of(cpu_of(rq)); | |
2470 | /* | |
2471 | * We now free resources of the root_domain we are migrating | |
2472 | * off. In the worst case, sched_setattr() may temporary fail | |
2473 | * until we complete the update. | |
2474 | */ | |
2475 | raw_spin_lock(&src_dl_b->lock); | |
8c0944ce | 2476 | __dl_sub(src_dl_b, p->dl.dl_bw, dl_bw_cpus(task_cpu(p))); |
7f51412a JL |
2477 | raw_spin_unlock(&src_dl_b->lock); |
2478 | } | |
2479 | ||
713a2e21 | 2480 | set_cpus_allowed_common(p, ctx); |
1baca4ce JL |
2481 | } |
2482 | ||
2483 | /* Assumes rq->lock is held */ | |
2484 | static void rq_online_dl(struct rq *rq) | |
2485 | { | |
2486 | if (rq->dl.overloaded) | |
2487 | dl_set_overload(rq); | |
6bfd6d72 | 2488 | |
16b26943 | 2489 | cpudl_set_freecpu(&rq->rd->cpudl, rq->cpu); |
6bfd6d72 | 2490 | if (rq->dl.dl_nr_running > 0) |
d8206bb3 | 2491 | cpudl_set(&rq->rd->cpudl, rq->cpu, rq->dl.earliest_dl.curr); |
1baca4ce JL |
2492 | } |
2493 | ||
2494 | /* Assumes rq->lock is held */ | |
2495 | static void rq_offline_dl(struct rq *rq) | |
2496 | { | |
2497 | if (rq->dl.overloaded) | |
2498 | dl_clear_overload(rq); | |
6bfd6d72 | 2499 | |
d8206bb3 | 2500 | cpudl_clear(&rq->rd->cpudl, rq->cpu); |
16b26943 | 2501 | cpudl_clear_freecpu(&rq->rd->cpudl, rq->cpu); |
1baca4ce JL |
2502 | } |
2503 | ||
a6c0e746 | 2504 | void __init init_sched_dl_class(void) |
1baca4ce JL |
2505 | { |
2506 | unsigned int i; | |
2507 | ||
2508 | for_each_possible_cpu(i) | |
2509 | zalloc_cpumask_var_node(&per_cpu(local_cpu_mask_dl, i), | |
2510 | GFP_KERNEL, cpu_to_node(i)); | |
2511 | } | |
2512 | ||
f9a25f77 MP |
2513 | void dl_add_task_root_domain(struct task_struct *p) |
2514 | { | |
2515 | struct rq_flags rf; | |
2516 | struct rq *rq; | |
2517 | struct dl_bw *dl_b; | |
2518 | ||
de40f33e DE |
2519 | raw_spin_lock_irqsave(&p->pi_lock, rf.flags); |
2520 | if (!dl_task(p)) { | |
2521 | raw_spin_unlock_irqrestore(&p->pi_lock, rf.flags); | |
2522 | return; | |
2523 | } | |
2524 | ||
2525 | rq = __task_rq_lock(p, &rf); | |
f9a25f77 MP |
2526 | |
2527 | dl_b = &rq->rd->dl_bw; | |
2528 | raw_spin_lock(&dl_b->lock); | |
2529 | ||
2530 | __dl_add(dl_b, p->dl.dl_bw, cpumask_weight(rq->rd->span)); | |
2531 | ||
2532 | raw_spin_unlock(&dl_b->lock); | |
2533 | ||
f9a25f77 MP |
2534 | task_rq_unlock(rq, p, &rf); |
2535 | } | |
2536 | ||
2537 | void dl_clear_root_domain(struct root_domain *rd) | |
2538 | { | |
2539 | unsigned long flags; | |
2540 | ||
2541 | raw_spin_lock_irqsave(&rd->dl_bw.lock, flags); | |
2542 | rd->dl_bw.total_bw = 0; | |
2543 | raw_spin_unlock_irqrestore(&rd->dl_bw.lock, flags); | |
2544 | } | |
2545 | ||
1baca4ce JL |
2546 | #endif /* CONFIG_SMP */ |
2547 | ||
aab03e05 DF |
2548 | static void switched_from_dl(struct rq *rq, struct task_struct *p) |
2549 | { | |
a649f237 | 2550 | /* |
209a0cbd LA |
2551 | * task_non_contending() can start the "inactive timer" (if the 0-lag |
2552 | * time is in the future). If the task switches back to dl before | |
2553 | * the "inactive timer" fires, it can continue to consume its current | |
2554 | * runtime using its current deadline. If it stays outside of | |
2555 | * SCHED_DEADLINE until the 0-lag time passes, inactive_task_timer() | |
2556 | * will reset the task parameters. | |
a649f237 | 2557 | */ |
209a0cbd LA |
2558 | if (task_on_rq_queued(p) && p->dl.dl_runtime) |
2559 | task_non_contending(p); | |
2560 | ||
6c24849f JL |
2561 | /* |
2562 | * In case a task is setscheduled out from SCHED_DEADLINE we need to | |
2563 | * keep track of that on its cpuset (for correct bandwidth tracking). | |
2564 | */ | |
2565 | dec_dl_tasks_cs(p); | |
2566 | ||
e117cb52 JL |
2567 | if (!task_on_rq_queued(p)) { |
2568 | /* | |
2569 | * Inactive timer is armed. However, p is leaving DEADLINE and | |
2570 | * might migrate away from this rq while continuing to run on | |
2571 | * some other class. We need to remove its contribution from | |
2572 | * this rq running_bw now, or sub_rq_bw (below) will complain. | |
2573 | */ | |
2574 | if (p->dl.dl_non_contending) | |
2575 | sub_running_bw(&p->dl, &rq->dl); | |
794a56eb | 2576 | sub_rq_bw(&p->dl, &rq->dl); |
e117cb52 | 2577 | } |
8fd27231 | 2578 | |
209a0cbd LA |
2579 | /* |
2580 | * We cannot use inactive_task_timer() to invoke sub_running_bw() | |
2581 | * at the 0-lag time, because the task could have been migrated | |
2582 | * while SCHED_OTHER in the meanwhile. | |
2583 | */ | |
2584 | if (p->dl.dl_non_contending) | |
2585 | p->dl.dl_non_contending = 0; | |
a5e7be3b | 2586 | |
1baca4ce JL |
2587 | /* |
2588 | * Since this might be the only -deadline task on the rq, | |
2589 | * this is the right place to try to pull some other one | |
97fb7a0a | 2590 | * from an overloaded CPU, if any. |
1baca4ce | 2591 | */ |
cd660911 WL |
2592 | if (!task_on_rq_queued(p) || rq->dl.dl_nr_running) |
2593 | return; | |
2594 | ||
02d8ec94 | 2595 | deadline_queue_pull_task(rq); |
aab03e05 DF |
2596 | } |
2597 | ||
1baca4ce JL |
2598 | /* |
2599 | * When switching to -deadline, we may overload the rq, then | |
2600 | * we try to push someone off, if possible. | |
2601 | */ | |
aab03e05 DF |
2602 | static void switched_to_dl(struct rq *rq, struct task_struct *p) |
2603 | { | |
209a0cbd LA |
2604 | if (hrtimer_try_to_cancel(&p->dl.inactive_timer) == 1) |
2605 | put_task_struct(p); | |
98b0a857 | 2606 | |
6c24849f JL |
2607 | /* |
2608 | * In case a task is setscheduled to SCHED_DEADLINE we need to keep | |
2609 | * track of that on its cpuset (for correct bandwidth tracking). | |
2610 | */ | |
2611 | inc_dl_tasks_cs(p); | |
2612 | ||
98b0a857 | 2613 | /* If p is not queued we will update its parameters at next wakeup. */ |
8fd27231 | 2614 | if (!task_on_rq_queued(p)) { |
794a56eb | 2615 | add_rq_bw(&p->dl, &rq->dl); |
98b0a857 | 2616 | |
8fd27231 LA |
2617 | return; |
2618 | } | |
72f9f3fd | 2619 | |
98b0a857 | 2620 | if (rq->curr != p) { |
1baca4ce | 2621 | #ifdef CONFIG_SMP |
4b53a341 | 2622 | if (p->nr_cpus_allowed > 1 && rq->dl.overloaded) |
02d8ec94 | 2623 | deadline_queue_push_tasks(rq); |
619bd4a7 | 2624 | #endif |
9916e214 | 2625 | if (dl_task(rq->curr)) |
e23edc86 | 2626 | wakeup_preempt_dl(rq, p, 0); |
9916e214 PZ |
2627 | else |
2628 | resched_curr(rq); | |
d7d60709 VD |
2629 | } else { |
2630 | update_dl_rq_load_avg(rq_clock_pelt(rq), rq, 0); | |
aab03e05 DF |
2631 | } |
2632 | } | |
2633 | ||
1baca4ce JL |
2634 | /* |
2635 | * If the scheduling parameters of a -deadline task changed, | |
2636 | * a push or pull operation might be needed. | |
2637 | */ | |
aab03e05 DF |
2638 | static void prio_changed_dl(struct rq *rq, struct task_struct *p, |
2639 | int oldprio) | |
2640 | { | |
7ea98dfa VS |
2641 | if (!task_on_rq_queued(p)) |
2642 | return; | |
2643 | ||
aab03e05 | 2644 | #ifdef CONFIG_SMP |
7ea98dfa VS |
2645 | /* |
2646 | * This might be too much, but unfortunately | |
2647 | * we don't have the old deadline value, and | |
2648 | * we can't argue if the task is increasing | |
2649 | * or lowering its prio, so... | |
2650 | */ | |
2651 | if (!rq->dl.overloaded) | |
2652 | deadline_queue_pull_task(rq); | |
1baca4ce | 2653 | |
7ea98dfa | 2654 | if (task_current(rq, p)) { |
1baca4ce JL |
2655 | /* |
2656 | * If we now have a earlier deadline task than p, | |
2657 | * then reschedule, provided p is still on this | |
2658 | * runqueue. | |
2659 | */ | |
9916e214 | 2660 | if (dl_time_before(rq->dl.earliest_dl.curr, p->dl.deadline)) |
8875125e | 2661 | resched_curr(rq); |
7ea98dfa | 2662 | } else { |
1baca4ce | 2663 | /* |
7ea98dfa VS |
2664 | * Current may not be deadline in case p was throttled but we |
2665 | * have just replenished it (e.g. rt_mutex_setprio()). | |
2666 | * | |
2667 | * Otherwise, if p was given an earlier deadline, reschedule. | |
1baca4ce | 2668 | */ |
7ea98dfa VS |
2669 | if (!dl_task(rq->curr) || |
2670 | dl_time_before(p->dl.deadline, rq->curr->dl.deadline)) | |
2671 | resched_curr(rq); | |
801ccdbf | 2672 | } |
7ea98dfa VS |
2673 | #else |
2674 | /* | |
2675 | * We don't know if p has a earlier or later deadline, so let's blindly | |
2676 | * set a (maybe not needed) rescheduling point. | |
2677 | */ | |
2678 | resched_curr(rq); | |
2679 | #endif | |
aab03e05 | 2680 | } |
aab03e05 | 2681 | |
530bfad1 HJ |
2682 | #ifdef CONFIG_SCHED_CORE |
2683 | static int task_is_throttled_dl(struct task_struct *p, int cpu) | |
2684 | { | |
2685 | return p->dl.dl_throttled; | |
2686 | } | |
2687 | #endif | |
2688 | ||
43c31ac0 PZ |
2689 | DEFINE_SCHED_CLASS(dl) = { |
2690 | ||
aab03e05 DF |
2691 | .enqueue_task = enqueue_task_dl, |
2692 | .dequeue_task = dequeue_task_dl, | |
2693 | .yield_task = yield_task_dl, | |
2694 | ||
e23edc86 | 2695 | .wakeup_preempt = wakeup_preempt_dl, |
aab03e05 DF |
2696 | |
2697 | .pick_next_task = pick_next_task_dl, | |
2698 | .put_prev_task = put_prev_task_dl, | |
03b7fad1 | 2699 | .set_next_task = set_next_task_dl, |
aab03e05 DF |
2700 | |
2701 | #ifdef CONFIG_SMP | |
6e2df058 | 2702 | .balance = balance_dl, |
21f56ffe | 2703 | .pick_task = pick_task_dl, |
aab03e05 | 2704 | .select_task_rq = select_task_rq_dl, |
209a0cbd | 2705 | .migrate_task_rq = migrate_task_rq_dl, |
1baca4ce JL |
2706 | .set_cpus_allowed = set_cpus_allowed_dl, |
2707 | .rq_online = rq_online_dl, | |
2708 | .rq_offline = rq_offline_dl, | |
1baca4ce | 2709 | .task_woken = task_woken_dl, |
a7c81556 | 2710 | .find_lock_rq = find_lock_later_rq, |
aab03e05 DF |
2711 | #endif |
2712 | ||
aab03e05 DF |
2713 | .task_tick = task_tick_dl, |
2714 | .task_fork = task_fork_dl, | |
aab03e05 DF |
2715 | |
2716 | .prio_changed = prio_changed_dl, | |
2717 | .switched_from = switched_from_dl, | |
2718 | .switched_to = switched_to_dl, | |
6e998916 SG |
2719 | |
2720 | .update_curr = update_curr_dl, | |
530bfad1 HJ |
2721 | #ifdef CONFIG_SCHED_CORE |
2722 | .task_is_throttled = task_is_throttled_dl, | |
2723 | #endif | |
aab03e05 | 2724 | }; |
acb32132 | 2725 | |
26762423 PL |
2726 | /* Used for dl_bw check and update, used under sched_rt_handler()::mutex */ |
2727 | static u64 dl_generation; | |
2728 | ||
06a76fe0 NP |
2729 | int sched_dl_global_validate(void) |
2730 | { | |
2731 | u64 runtime = global_rt_runtime(); | |
2732 | u64 period = global_rt_period(); | |
2733 | u64 new_bw = to_ratio(period, runtime); | |
26762423 | 2734 | u64 gen = ++dl_generation; |
06a76fe0 | 2735 | struct dl_bw *dl_b; |
a57415f5 | 2736 | int cpu, cpus, ret = 0; |
06a76fe0 NP |
2737 | unsigned long flags; |
2738 | ||
2739 | /* | |
2740 | * Here we want to check the bandwidth not being set to some | |
2741 | * value smaller than the currently allocated bandwidth in | |
2742 | * any of the root_domains. | |
06a76fe0 NP |
2743 | */ |
2744 | for_each_possible_cpu(cpu) { | |
2745 | rcu_read_lock_sched(); | |
26762423 PL |
2746 | |
2747 | if (dl_bw_visited(cpu, gen)) | |
2748 | goto next; | |
2749 | ||
06a76fe0 | 2750 | dl_b = dl_bw_of(cpu); |
a57415f5 | 2751 | cpus = dl_bw_cpus(cpu); |
06a76fe0 NP |
2752 | |
2753 | raw_spin_lock_irqsave(&dl_b->lock, flags); | |
a57415f5 | 2754 | if (new_bw * cpus < dl_b->total_bw) |
06a76fe0 NP |
2755 | ret = -EBUSY; |
2756 | raw_spin_unlock_irqrestore(&dl_b->lock, flags); | |
2757 | ||
26762423 | 2758 | next: |
06a76fe0 NP |
2759 | rcu_read_unlock_sched(); |
2760 | ||
2761 | if (ret) | |
2762 | break; | |
2763 | } | |
2764 | ||
2765 | return ret; | |
2766 | } | |
2767 | ||
ba4f7bc1 | 2768 | static void init_dl_rq_bw_ratio(struct dl_rq *dl_rq) |
06a76fe0 NP |
2769 | { |
2770 | if (global_rt_runtime() == RUNTIME_INF) { | |
2771 | dl_rq->bw_ratio = 1 << RATIO_SHIFT; | |
6a9d623a | 2772 | dl_rq->max_bw = dl_rq->extra_bw = 1 << BW_SHIFT; |
06a76fe0 NP |
2773 | } else { |
2774 | dl_rq->bw_ratio = to_ratio(global_rt_runtime(), | |
2775 | global_rt_period()) >> (BW_SHIFT - RATIO_SHIFT); | |
6a9d623a VP |
2776 | dl_rq->max_bw = dl_rq->extra_bw = |
2777 | to_ratio(global_rt_period(), global_rt_runtime()); | |
06a76fe0 NP |
2778 | } |
2779 | } | |
2780 | ||
2781 | void sched_dl_do_global(void) | |
2782 | { | |
2783 | u64 new_bw = -1; | |
26762423 | 2784 | u64 gen = ++dl_generation; |
06a76fe0 NP |
2785 | struct dl_bw *dl_b; |
2786 | int cpu; | |
2787 | unsigned long flags; | |
2788 | ||
06a76fe0 NP |
2789 | if (global_rt_runtime() != RUNTIME_INF) |
2790 | new_bw = to_ratio(global_rt_period(), global_rt_runtime()); | |
2791 | ||
06a76fe0 NP |
2792 | for_each_possible_cpu(cpu) { |
2793 | rcu_read_lock_sched(); | |
26762423 PL |
2794 | |
2795 | if (dl_bw_visited(cpu, gen)) { | |
2796 | rcu_read_unlock_sched(); | |
2797 | continue; | |
2798 | } | |
2799 | ||
06a76fe0 NP |
2800 | dl_b = dl_bw_of(cpu); |
2801 | ||
2802 | raw_spin_lock_irqsave(&dl_b->lock, flags); | |
2803 | dl_b->bw = new_bw; | |
2804 | raw_spin_unlock_irqrestore(&dl_b->lock, flags); | |
2805 | ||
2806 | rcu_read_unlock_sched(); | |
2807 | init_dl_rq_bw_ratio(&cpu_rq(cpu)->dl); | |
2808 | } | |
2809 | } | |
2810 | ||
2811 | /* | |
2812 | * We must be sure that accepting a new task (or allowing changing the | |
2813 | * parameters of an existing one) is consistent with the bandwidth | |
2814 | * constraints. If yes, this function also accordingly updates the currently | |
2815 | * allocated bandwidth to reflect the new situation. | |
2816 | * | |
2817 | * This function is called while holding p's rq->lock. | |
2818 | */ | |
2819 | int sched_dl_overflow(struct task_struct *p, int policy, | |
2820 | const struct sched_attr *attr) | |
2821 | { | |
06a76fe0 NP |
2822 | u64 period = attr->sched_period ?: attr->sched_deadline; |
2823 | u64 runtime = attr->sched_runtime; | |
2824 | u64 new_bw = dl_policy(policy) ? to_ratio(period, runtime) : 0; | |
60ffd5ed LA |
2825 | int cpus, err = -1, cpu = task_cpu(p); |
2826 | struct dl_bw *dl_b = dl_bw_of(cpu); | |
2827 | unsigned long cap; | |
06a76fe0 | 2828 | |
794a56eb JL |
2829 | if (attr->sched_flags & SCHED_FLAG_SUGOV) |
2830 | return 0; | |
2831 | ||
06a76fe0 NP |
2832 | /* !deadline task may carry old deadline bandwidth */ |
2833 | if (new_bw == p->dl.dl_bw && task_has_dl_policy(p)) | |
2834 | return 0; | |
2835 | ||
2836 | /* | |
2837 | * Either if a task, enters, leave, or stays -deadline but changes | |
2838 | * its parameters, we may need to update accordingly the total | |
2839 | * allocated bandwidth of the container. | |
2840 | */ | |
2841 | raw_spin_lock(&dl_b->lock); | |
60ffd5ed LA |
2842 | cpus = dl_bw_cpus(cpu); |
2843 | cap = dl_bw_capacity(cpu); | |
2844 | ||
06a76fe0 | 2845 | if (dl_policy(policy) && !task_has_dl_policy(p) && |
60ffd5ed | 2846 | !__dl_overflow(dl_b, cap, 0, new_bw)) { |
06a76fe0 | 2847 | if (hrtimer_active(&p->dl.inactive_timer)) |
8c0944ce | 2848 | __dl_sub(dl_b, p->dl.dl_bw, cpus); |
06a76fe0 NP |
2849 | __dl_add(dl_b, new_bw, cpus); |
2850 | err = 0; | |
2851 | } else if (dl_policy(policy) && task_has_dl_policy(p) && | |
60ffd5ed | 2852 | !__dl_overflow(dl_b, cap, p->dl.dl_bw, new_bw)) { |
06a76fe0 NP |
2853 | /* |
2854 | * XXX this is slightly incorrect: when the task | |
2855 | * utilization decreases, we should delay the total | |
2856 | * utilization change until the task's 0-lag point. | |
2857 | * But this would require to set the task's "inactive | |
2858 | * timer" when the task is not inactive. | |
2859 | */ | |
8c0944ce | 2860 | __dl_sub(dl_b, p->dl.dl_bw, cpus); |
06a76fe0 NP |
2861 | __dl_add(dl_b, new_bw, cpus); |
2862 | dl_change_utilization(p, new_bw); | |
2863 | err = 0; | |
2864 | } else if (!dl_policy(policy) && task_has_dl_policy(p)) { | |
2865 | /* | |
2866 | * Do not decrease the total deadline utilization here, | |
2867 | * switched_from_dl() will take care to do it at the correct | |
2868 | * (0-lag) time. | |
2869 | */ | |
2870 | err = 0; | |
2871 | } | |
2872 | raw_spin_unlock(&dl_b->lock); | |
2873 | ||
2874 | return err; | |
2875 | } | |
2876 | ||
2877 | /* | |
2878 | * This function initializes the sched_dl_entity of a newly becoming | |
2879 | * SCHED_DEADLINE task. | |
2880 | * | |
2881 | * Only the static values are considered here, the actual runtime and the | |
2882 | * absolute deadline will be properly calculated when the task is enqueued | |
2883 | * for the first time with its new policy. | |
2884 | */ | |
2885 | void __setparam_dl(struct task_struct *p, const struct sched_attr *attr) | |
2886 | { | |
2887 | struct sched_dl_entity *dl_se = &p->dl; | |
2888 | ||
2889 | dl_se->dl_runtime = attr->sched_runtime; | |
2890 | dl_se->dl_deadline = attr->sched_deadline; | |
2891 | dl_se->dl_period = attr->sched_period ?: dl_se->dl_deadline; | |
f9509153 | 2892 | dl_se->flags = attr->sched_flags & SCHED_DL_FLAGS; |
06a76fe0 NP |
2893 | dl_se->dl_bw = to_ratio(dl_se->dl_period, dl_se->dl_runtime); |
2894 | dl_se->dl_density = to_ratio(dl_se->dl_deadline, dl_se->dl_runtime); | |
2895 | } | |
2896 | ||
2897 | void __getparam_dl(struct task_struct *p, struct sched_attr *attr) | |
2898 | { | |
2899 | struct sched_dl_entity *dl_se = &p->dl; | |
2900 | ||
2901 | attr->sched_priority = p->rt_priority; | |
2902 | attr->sched_runtime = dl_se->dl_runtime; | |
2903 | attr->sched_deadline = dl_se->dl_deadline; | |
2904 | attr->sched_period = dl_se->dl_period; | |
f9509153 QP |
2905 | attr->sched_flags &= ~SCHED_DL_FLAGS; |
2906 | attr->sched_flags |= dl_se->flags; | |
06a76fe0 NP |
2907 | } |
2908 | ||
2909 | /* | |
2910 | * This function validates the new parameters of a -deadline task. | |
2911 | * We ask for the deadline not being zero, and greater or equal | |
2912 | * than the runtime, as well as the period of being zero or | |
2913 | * greater than deadline. Furthermore, we have to be sure that | |
2914 | * user parameters are above the internal resolution of 1us (we | |
2915 | * check sched_runtime only since it is always the smaller one) and | |
2916 | * below 2^63 ns (we have to check both sched_deadline and | |
2917 | * sched_period, as the latter can be zero). | |
2918 | */ | |
2919 | bool __checkparam_dl(const struct sched_attr *attr) | |
2920 | { | |
b4098bfc PZ |
2921 | u64 period, max, min; |
2922 | ||
794a56eb JL |
2923 | /* special dl tasks don't actually use any parameter */ |
2924 | if (attr->sched_flags & SCHED_FLAG_SUGOV) | |
2925 | return true; | |
2926 | ||
06a76fe0 NP |
2927 | /* deadline != 0 */ |
2928 | if (attr->sched_deadline == 0) | |
2929 | return false; | |
2930 | ||
2931 | /* | |
2932 | * Since we truncate DL_SCALE bits, make sure we're at least | |
2933 | * that big. | |
2934 | */ | |
2935 | if (attr->sched_runtime < (1ULL << DL_SCALE)) | |
2936 | return false; | |
2937 | ||
2938 | /* | |
2939 | * Since we use the MSB for wrap-around and sign issues, make | |
2940 | * sure it's not set (mind that period can be equal to zero). | |
2941 | */ | |
2942 | if (attr->sched_deadline & (1ULL << 63) || | |
2943 | attr->sched_period & (1ULL << 63)) | |
2944 | return false; | |
2945 | ||
b4098bfc PZ |
2946 | period = attr->sched_period; |
2947 | if (!period) | |
2948 | period = attr->sched_deadline; | |
2949 | ||
06a76fe0 | 2950 | /* runtime <= deadline <= period (if period != 0) */ |
b4098bfc | 2951 | if (period < attr->sched_deadline || |
06a76fe0 NP |
2952 | attr->sched_deadline < attr->sched_runtime) |
2953 | return false; | |
2954 | ||
b4098bfc PZ |
2955 | max = (u64)READ_ONCE(sysctl_sched_dl_period_max) * NSEC_PER_USEC; |
2956 | min = (u64)READ_ONCE(sysctl_sched_dl_period_min) * NSEC_PER_USEC; | |
2957 | ||
2958 | if (period < min || period > max) | |
2959 | return false; | |
2960 | ||
06a76fe0 NP |
2961 | return true; |
2962 | } | |
2963 | ||
2964 | /* | |
2965 | * This function clears the sched_dl_entity static params. | |
2966 | */ | |
2967 | void __dl_clear_params(struct task_struct *p) | |
2968 | { | |
2969 | struct sched_dl_entity *dl_se = &p->dl; | |
2970 | ||
97fb7a0a IM |
2971 | dl_se->dl_runtime = 0; |
2972 | dl_se->dl_deadline = 0; | |
2973 | dl_se->dl_period = 0; | |
2974 | dl_se->flags = 0; | |
2975 | dl_se->dl_bw = 0; | |
2976 | dl_se->dl_density = 0; | |
06a76fe0 | 2977 | |
97fb7a0a IM |
2978 | dl_se->dl_throttled = 0; |
2979 | dl_se->dl_yielded = 0; | |
2980 | dl_se->dl_non_contending = 0; | |
2981 | dl_se->dl_overrun = 0; | |
2279f540 JL |
2982 | |
2983 | #ifdef CONFIG_RT_MUTEXES | |
2984 | dl_se->pi_se = dl_se; | |
2985 | #endif | |
06a76fe0 NP |
2986 | } |
2987 | ||
2988 | bool dl_param_changed(struct task_struct *p, const struct sched_attr *attr) | |
2989 | { | |
2990 | struct sched_dl_entity *dl_se = &p->dl; | |
2991 | ||
2992 | if (dl_se->dl_runtime != attr->sched_runtime || | |
2993 | dl_se->dl_deadline != attr->sched_deadline || | |
2994 | dl_se->dl_period != attr->sched_period || | |
f9509153 | 2995 | dl_se->flags != (attr->sched_flags & SCHED_DL_FLAGS)) |
06a76fe0 NP |
2996 | return true; |
2997 | ||
2998 | return false; | |
2999 | } | |
3000 | ||
3001 | #ifdef CONFIG_SMP | |
06a76fe0 NP |
3002 | int dl_cpuset_cpumask_can_shrink(const struct cpumask *cur, |
3003 | const struct cpumask *trial) | |
3004 | { | |
6092478b | 3005 | unsigned long flags, cap; |
06a76fe0 | 3006 | struct dl_bw *cur_dl_b; |
6092478b | 3007 | int ret = 1; |
06a76fe0 NP |
3008 | |
3009 | rcu_read_lock_sched(); | |
3010 | cur_dl_b = dl_bw_of(cpumask_any(cur)); | |
6092478b | 3011 | cap = __dl_bw_capacity(trial); |
06a76fe0 | 3012 | raw_spin_lock_irqsave(&cur_dl_b->lock, flags); |
6092478b | 3013 | if (__dl_overflow(cur_dl_b, cap, 0, 0)) |
06a76fe0 NP |
3014 | ret = 0; |
3015 | raw_spin_unlock_irqrestore(&cur_dl_b->lock, flags); | |
3016 | rcu_read_unlock_sched(); | |
97fb7a0a | 3017 | |
06a76fe0 NP |
3018 | return ret; |
3019 | } | |
3020 | ||
85989106 DE |
3021 | enum dl_bw_request { |
3022 | dl_bw_req_check_overflow = 0, | |
3023 | dl_bw_req_alloc, | |
3024 | dl_bw_req_free | |
3025 | }; | |
3026 | ||
3027 | static int dl_bw_manage(enum dl_bw_request req, int cpu, u64 dl_bw) | |
06a76fe0 | 3028 | { |
85989106 | 3029 | unsigned long flags; |
06a76fe0 | 3030 | struct dl_bw *dl_b; |
85989106 | 3031 | bool overflow = 0; |
06a76fe0 NP |
3032 | |
3033 | rcu_read_lock_sched(); | |
3034 | dl_b = dl_bw_of(cpu); | |
3035 | raw_spin_lock_irqsave(&dl_b->lock, flags); | |
772b6539 | 3036 | |
85989106 DE |
3037 | if (req == dl_bw_req_free) { |
3038 | __dl_sub(dl_b, dl_bw, dl_bw_cpus(cpu)); | |
3039 | } else { | |
3040 | unsigned long cap = dl_bw_capacity(cpu); | |
3041 | ||
3042 | overflow = __dl_overflow(dl_b, cap, 0, dl_bw); | |
3043 | ||
3044 | if (req == dl_bw_req_alloc && !overflow) { | |
3045 | /* | |
3046 | * We reserve space in the destination | |
3047 | * root_domain, as we can't fail after this point. | |
3048 | * We will free resources in the source root_domain | |
3049 | * later on (see set_cpus_allowed_dl()). | |
3050 | */ | |
3051 | __dl_add(dl_b, dl_bw, dl_bw_cpus(cpu)); | |
3052 | } | |
772b6539 DE |
3053 | } |
3054 | ||
06a76fe0 NP |
3055 | raw_spin_unlock_irqrestore(&dl_b->lock, flags); |
3056 | rcu_read_unlock_sched(); | |
97fb7a0a | 3057 | |
772b6539 | 3058 | return overflow ? -EBUSY : 0; |
06a76fe0 | 3059 | } |
85989106 DE |
3060 | |
3061 | int dl_bw_check_overflow(int cpu) | |
3062 | { | |
3063 | return dl_bw_manage(dl_bw_req_check_overflow, cpu, 0); | |
3064 | } | |
3065 | ||
3066 | int dl_bw_alloc(int cpu, u64 dl_bw) | |
3067 | { | |
3068 | return dl_bw_manage(dl_bw_req_alloc, cpu, dl_bw); | |
3069 | } | |
3070 | ||
3071 | void dl_bw_free(int cpu, u64 dl_bw) | |
3072 | { | |
3073 | dl_bw_manage(dl_bw_req_free, cpu, dl_bw); | |
3074 | } | |
06a76fe0 NP |
3075 | #endif |
3076 | ||
acb32132 | 3077 | #ifdef CONFIG_SCHED_DEBUG |
acb32132 WL |
3078 | void print_dl_stats(struct seq_file *m, int cpu) |
3079 | { | |
3080 | print_dl_rq(m, cpu, &cpu_rq(cpu)->dl); | |
3081 | } | |
3082 | #endif /* CONFIG_SCHED_DEBUG */ |