Commit | Line | Data |
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bf0f6f24 IM |
1 | /* |
2 | * Completely Fair Scheduling (CFS) Class (SCHED_NORMAL/SCHED_BATCH) | |
3 | * | |
4 | * Copyright (C) 2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> | |
5 | * | |
6 | * Interactivity improvements by Mike Galbraith | |
7 | * (C) 2007 Mike Galbraith <efault@gmx.de> | |
8 | * | |
9 | * Various enhancements by Dmitry Adamushko. | |
10 | * (C) 2007 Dmitry Adamushko <dmitry.adamushko@gmail.com> | |
11 | * | |
12 | * Group scheduling enhancements by Srivatsa Vaddagiri | |
13 | * Copyright IBM Corporation, 2007 | |
14 | * Author: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> | |
15 | * | |
16 | * Scaled math optimizations by Thomas Gleixner | |
17 | * Copyright (C) 2007, Thomas Gleixner <tglx@linutronix.de> | |
21805085 PZ |
18 | * |
19 | * Adaptive scheduling granularity, math enhancements by Peter Zijlstra | |
20 | * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com> | |
bf0f6f24 IM |
21 | */ |
22 | ||
9745512c AV |
23 | #include <linux/latencytop.h> |
24 | ||
bf0f6f24 | 25 | /* |
21805085 | 26 | * Targeted preemption latency for CPU-bound tasks: |
722aab0c | 27 | * (default: 20ms * (1 + ilog(ncpus)), units: nanoseconds) |
bf0f6f24 | 28 | * |
21805085 | 29 | * NOTE: this latency value is not the same as the concept of |
d274a4ce IM |
30 | * 'timeslice length' - timeslices in CFS are of variable length |
31 | * and have no persistent notion like in traditional, time-slice | |
32 | * based scheduling concepts. | |
bf0f6f24 | 33 | * |
d274a4ce IM |
34 | * (to see the precise effective timeslice length of your workload, |
35 | * run vmstat and monitor the context-switches (cs) field) | |
bf0f6f24 | 36 | */ |
19978ca6 | 37 | unsigned int sysctl_sched_latency = 20000000ULL; |
2bd8e6d4 IM |
38 | |
39 | /* | |
b2be5e96 | 40 | * Minimal preemption granularity for CPU-bound tasks: |
722aab0c | 41 | * (default: 4 msec * (1 + ilog(ncpus)), units: nanoseconds) |
2bd8e6d4 | 42 | */ |
722aab0c | 43 | unsigned int sysctl_sched_min_granularity = 4000000ULL; |
21805085 PZ |
44 | |
45 | /* | |
b2be5e96 PZ |
46 | * is kept at sysctl_sched_latency / sysctl_sched_min_granularity |
47 | */ | |
722aab0c | 48 | static unsigned int sched_nr_latency = 5; |
b2be5e96 PZ |
49 | |
50 | /* | |
51 | * After fork, child runs first. (default) If set to 0 then | |
52 | * parent will (try to) run first. | |
21805085 | 53 | */ |
b2be5e96 | 54 | const_debug unsigned int sysctl_sched_child_runs_first = 1; |
bf0f6f24 | 55 | |
1799e35d IM |
56 | /* |
57 | * sys_sched_yield() compat mode | |
58 | * | |
59 | * This option switches the agressive yield implementation of the | |
60 | * old scheduler back on. | |
61 | */ | |
62 | unsigned int __read_mostly sysctl_sched_compat_yield; | |
63 | ||
bf0f6f24 IM |
64 | /* |
65 | * SCHED_OTHER wake-up granularity. | |
0bbd3336 | 66 | * (default: 10 msec * (1 + ilog(ncpus)), units: nanoseconds) |
bf0f6f24 IM |
67 | * |
68 | * This option delays the preemption effects of decoupled workloads | |
69 | * and reduces their over-scheduling. Synchronous workloads will still | |
70 | * have immediate wakeup/sleep latencies. | |
71 | */ | |
0bbd3336 | 72 | unsigned int sysctl_sched_wakeup_granularity = 10000000UL; |
bf0f6f24 | 73 | |
da84d961 IM |
74 | const_debug unsigned int sysctl_sched_migration_cost = 500000UL; |
75 | ||
bf0f6f24 IM |
76 | /************************************************************** |
77 | * CFS operations on generic schedulable entities: | |
78 | */ | |
79 | ||
62160e3f | 80 | #ifdef CONFIG_FAIR_GROUP_SCHED |
bf0f6f24 | 81 | |
62160e3f | 82 | /* cpu runqueue to which this cfs_rq is attached */ |
bf0f6f24 IM |
83 | static inline struct rq *rq_of(struct cfs_rq *cfs_rq) |
84 | { | |
62160e3f | 85 | return cfs_rq->rq; |
bf0f6f24 IM |
86 | } |
87 | ||
62160e3f IM |
88 | /* An entity is a task if it doesn't "own" a runqueue */ |
89 | #define entity_is_task(se) (!se->my_q) | |
bf0f6f24 | 90 | |
62160e3f | 91 | #else /* CONFIG_FAIR_GROUP_SCHED */ |
bf0f6f24 | 92 | |
62160e3f IM |
93 | static inline struct rq *rq_of(struct cfs_rq *cfs_rq) |
94 | { | |
95 | return container_of(cfs_rq, struct rq, cfs); | |
bf0f6f24 IM |
96 | } |
97 | ||
98 | #define entity_is_task(se) 1 | |
99 | ||
bf0f6f24 IM |
100 | #endif /* CONFIG_FAIR_GROUP_SCHED */ |
101 | ||
102 | static inline struct task_struct *task_of(struct sched_entity *se) | |
103 | { | |
104 | return container_of(se, struct task_struct, se); | |
105 | } | |
106 | ||
107 | ||
108 | /************************************************************** | |
109 | * Scheduling class tree data structure manipulation methods: | |
110 | */ | |
111 | ||
0702e3eb | 112 | static inline u64 max_vruntime(u64 min_vruntime, u64 vruntime) |
02e0431a | 113 | { |
368059a9 PZ |
114 | s64 delta = (s64)(vruntime - min_vruntime); |
115 | if (delta > 0) | |
02e0431a PZ |
116 | min_vruntime = vruntime; |
117 | ||
118 | return min_vruntime; | |
119 | } | |
120 | ||
0702e3eb | 121 | static inline u64 min_vruntime(u64 min_vruntime, u64 vruntime) |
b0ffd246 PZ |
122 | { |
123 | s64 delta = (s64)(vruntime - min_vruntime); | |
124 | if (delta < 0) | |
125 | min_vruntime = vruntime; | |
126 | ||
127 | return min_vruntime; | |
128 | } | |
129 | ||
0702e3eb | 130 | static inline s64 entity_key(struct cfs_rq *cfs_rq, struct sched_entity *se) |
9014623c | 131 | { |
30cfdcfc | 132 | return se->vruntime - cfs_rq->min_vruntime; |
9014623c PZ |
133 | } |
134 | ||
bf0f6f24 IM |
135 | /* |
136 | * Enqueue an entity into the rb-tree: | |
137 | */ | |
0702e3eb | 138 | static void __enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 IM |
139 | { |
140 | struct rb_node **link = &cfs_rq->tasks_timeline.rb_node; | |
141 | struct rb_node *parent = NULL; | |
142 | struct sched_entity *entry; | |
9014623c | 143 | s64 key = entity_key(cfs_rq, se); |
bf0f6f24 IM |
144 | int leftmost = 1; |
145 | ||
146 | /* | |
147 | * Find the right place in the rbtree: | |
148 | */ | |
149 | while (*link) { | |
150 | parent = *link; | |
151 | entry = rb_entry(parent, struct sched_entity, run_node); | |
152 | /* | |
153 | * We dont care about collisions. Nodes with | |
154 | * the same key stay together. | |
155 | */ | |
9014623c | 156 | if (key < entity_key(cfs_rq, entry)) { |
bf0f6f24 IM |
157 | link = &parent->rb_left; |
158 | } else { | |
159 | link = &parent->rb_right; | |
160 | leftmost = 0; | |
161 | } | |
162 | } | |
163 | ||
164 | /* | |
165 | * Maintain a cache of leftmost tree entries (it is frequently | |
166 | * used): | |
167 | */ | |
3fe69747 | 168 | if (leftmost) { |
57cb499d | 169 | cfs_rq->rb_leftmost = &se->run_node; |
3fe69747 PZ |
170 | /* |
171 | * maintain cfs_rq->min_vruntime to be a monotonic increasing | |
172 | * value tracking the leftmost vruntime in the tree. | |
173 | */ | |
174 | cfs_rq->min_vruntime = | |
175 | max_vruntime(cfs_rq->min_vruntime, se->vruntime); | |
176 | } | |
bf0f6f24 IM |
177 | |
178 | rb_link_node(&se->run_node, parent, link); | |
179 | rb_insert_color(&se->run_node, &cfs_rq->tasks_timeline); | |
bf0f6f24 IM |
180 | } |
181 | ||
0702e3eb | 182 | static void __dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 183 | { |
3fe69747 PZ |
184 | if (cfs_rq->rb_leftmost == &se->run_node) { |
185 | struct rb_node *next_node; | |
186 | struct sched_entity *next; | |
187 | ||
188 | next_node = rb_next(&se->run_node); | |
189 | cfs_rq->rb_leftmost = next_node; | |
190 | ||
191 | if (next_node) { | |
192 | next = rb_entry(next_node, | |
193 | struct sched_entity, run_node); | |
194 | cfs_rq->min_vruntime = | |
195 | max_vruntime(cfs_rq->min_vruntime, | |
196 | next->vruntime); | |
197 | } | |
198 | } | |
e9acbff6 | 199 | |
aa2ac252 PZ |
200 | if (cfs_rq->next == se) |
201 | cfs_rq->next = NULL; | |
202 | ||
bf0f6f24 | 203 | rb_erase(&se->run_node, &cfs_rq->tasks_timeline); |
bf0f6f24 IM |
204 | } |
205 | ||
206 | static inline struct rb_node *first_fair(struct cfs_rq *cfs_rq) | |
207 | { | |
208 | return cfs_rq->rb_leftmost; | |
209 | } | |
210 | ||
211 | static struct sched_entity *__pick_next_entity(struct cfs_rq *cfs_rq) | |
212 | { | |
213 | return rb_entry(first_fair(cfs_rq), struct sched_entity, run_node); | |
214 | } | |
215 | ||
aeb73b04 PZ |
216 | static inline struct sched_entity *__pick_last_entity(struct cfs_rq *cfs_rq) |
217 | { | |
7eee3e67 | 218 | struct rb_node *last = rb_last(&cfs_rq->tasks_timeline); |
aeb73b04 | 219 | |
70eee74b BS |
220 | if (!last) |
221 | return NULL; | |
7eee3e67 IM |
222 | |
223 | return rb_entry(last, struct sched_entity, run_node); | |
aeb73b04 PZ |
224 | } |
225 | ||
bf0f6f24 IM |
226 | /************************************************************** |
227 | * Scheduling class statistics methods: | |
228 | */ | |
229 | ||
b2be5e96 PZ |
230 | #ifdef CONFIG_SCHED_DEBUG |
231 | int sched_nr_latency_handler(struct ctl_table *table, int write, | |
232 | struct file *filp, void __user *buffer, size_t *lenp, | |
233 | loff_t *ppos) | |
234 | { | |
235 | int ret = proc_dointvec_minmax(table, write, filp, buffer, lenp, ppos); | |
236 | ||
237 | if (ret || !write) | |
238 | return ret; | |
239 | ||
240 | sched_nr_latency = DIV_ROUND_UP(sysctl_sched_latency, | |
241 | sysctl_sched_min_granularity); | |
242 | ||
243 | return 0; | |
244 | } | |
245 | #endif | |
647e7cac IM |
246 | |
247 | /* | |
248 | * The idea is to set a period in which each task runs once. | |
249 | * | |
250 | * When there are too many tasks (sysctl_sched_nr_latency) we have to stretch | |
251 | * this period because otherwise the slices get too small. | |
252 | * | |
253 | * p = (nr <= nl) ? l : l*nr/nl | |
254 | */ | |
4d78e7b6 PZ |
255 | static u64 __sched_period(unsigned long nr_running) |
256 | { | |
257 | u64 period = sysctl_sched_latency; | |
b2be5e96 | 258 | unsigned long nr_latency = sched_nr_latency; |
4d78e7b6 PZ |
259 | |
260 | if (unlikely(nr_running > nr_latency)) { | |
4bf0b771 | 261 | period = sysctl_sched_min_granularity; |
4d78e7b6 | 262 | period *= nr_running; |
4d78e7b6 PZ |
263 | } |
264 | ||
265 | return period; | |
266 | } | |
267 | ||
647e7cac IM |
268 | /* |
269 | * We calculate the wall-time slice from the period by taking a part | |
270 | * proportional to the weight. | |
271 | * | |
272 | * s = p*w/rw | |
273 | */ | |
6d0f0ebd | 274 | static u64 sched_slice(struct cfs_rq *cfs_rq, struct sched_entity *se) |
21805085 | 275 | { |
6a6029b8 IM |
276 | return calc_delta_mine(__sched_period(cfs_rq->nr_running), |
277 | se->load.weight, &cfs_rq->load); | |
bf0f6f24 IM |
278 | } |
279 | ||
647e7cac IM |
280 | /* |
281 | * We calculate the vruntime slice. | |
282 | * | |
283 | * vs = s/w = p/rw | |
284 | */ | |
285 | static u64 __sched_vslice(unsigned long rq_weight, unsigned long nr_running) | |
67e9fb2a | 286 | { |
647e7cac | 287 | u64 vslice = __sched_period(nr_running); |
67e9fb2a | 288 | |
10b77724 | 289 | vslice *= NICE_0_LOAD; |
647e7cac | 290 | do_div(vslice, rq_weight); |
67e9fb2a | 291 | |
647e7cac IM |
292 | return vslice; |
293 | } | |
5f6d858e | 294 | |
647e7cac IM |
295 | static u64 sched_vslice_add(struct cfs_rq *cfs_rq, struct sched_entity *se) |
296 | { | |
297 | return __sched_vslice(cfs_rq->load.weight + se->load.weight, | |
298 | cfs_rq->nr_running + 1); | |
67e9fb2a PZ |
299 | } |
300 | ||
bf0f6f24 IM |
301 | /* |
302 | * Update the current task's runtime statistics. Skip current tasks that | |
303 | * are not in our scheduling class. | |
304 | */ | |
305 | static inline void | |
8ebc91d9 IM |
306 | __update_curr(struct cfs_rq *cfs_rq, struct sched_entity *curr, |
307 | unsigned long delta_exec) | |
bf0f6f24 | 308 | { |
bbdba7c0 | 309 | unsigned long delta_exec_weighted; |
bf0f6f24 | 310 | |
8179ca23 | 311 | schedstat_set(curr->exec_max, max((u64)delta_exec, curr->exec_max)); |
bf0f6f24 IM |
312 | |
313 | curr->sum_exec_runtime += delta_exec; | |
7a62eabc | 314 | schedstat_add(cfs_rq, exec_clock, delta_exec); |
e9acbff6 IM |
315 | delta_exec_weighted = delta_exec; |
316 | if (unlikely(curr->load.weight != NICE_0_LOAD)) { | |
317 | delta_exec_weighted = calc_delta_fair(delta_exec_weighted, | |
318 | &curr->load); | |
319 | } | |
320 | curr->vruntime += delta_exec_weighted; | |
bf0f6f24 IM |
321 | } |
322 | ||
b7cc0896 | 323 | static void update_curr(struct cfs_rq *cfs_rq) |
bf0f6f24 | 324 | { |
429d43bc | 325 | struct sched_entity *curr = cfs_rq->curr; |
8ebc91d9 | 326 | u64 now = rq_of(cfs_rq)->clock; |
bf0f6f24 IM |
327 | unsigned long delta_exec; |
328 | ||
329 | if (unlikely(!curr)) | |
330 | return; | |
331 | ||
332 | /* | |
333 | * Get the amount of time the current task was running | |
334 | * since the last time we changed load (this cannot | |
335 | * overflow on 32 bits): | |
336 | */ | |
8ebc91d9 | 337 | delta_exec = (unsigned long)(now - curr->exec_start); |
bf0f6f24 | 338 | |
8ebc91d9 IM |
339 | __update_curr(cfs_rq, curr, delta_exec); |
340 | curr->exec_start = now; | |
d842de87 SV |
341 | |
342 | if (entity_is_task(curr)) { | |
343 | struct task_struct *curtask = task_of(curr); | |
344 | ||
345 | cpuacct_charge(curtask, delta_exec); | |
346 | } | |
bf0f6f24 IM |
347 | } |
348 | ||
349 | static inline void | |
5870db5b | 350 | update_stats_wait_start(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 351 | { |
d281918d | 352 | schedstat_set(se->wait_start, rq_of(cfs_rq)->clock); |
bf0f6f24 IM |
353 | } |
354 | ||
bf0f6f24 IM |
355 | /* |
356 | * Task is being enqueued - update stats: | |
357 | */ | |
d2417e5a | 358 | static void update_stats_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 359 | { |
bf0f6f24 IM |
360 | /* |
361 | * Are we enqueueing a waiting task? (for current tasks | |
362 | * a dequeue/enqueue event is a NOP) | |
363 | */ | |
429d43bc | 364 | if (se != cfs_rq->curr) |
5870db5b | 365 | update_stats_wait_start(cfs_rq, se); |
bf0f6f24 IM |
366 | } |
367 | ||
bf0f6f24 | 368 | static void |
9ef0a961 | 369 | update_stats_wait_end(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 370 | { |
bbdba7c0 IM |
371 | schedstat_set(se->wait_max, max(se->wait_max, |
372 | rq_of(cfs_rq)->clock - se->wait_start)); | |
6d082592 AV |
373 | schedstat_set(se->wait_count, se->wait_count + 1); |
374 | schedstat_set(se->wait_sum, se->wait_sum + | |
375 | rq_of(cfs_rq)->clock - se->wait_start); | |
6cfb0d5d | 376 | schedstat_set(se->wait_start, 0); |
bf0f6f24 IM |
377 | } |
378 | ||
379 | static inline void | |
19b6a2e3 | 380 | update_stats_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 381 | { |
bf0f6f24 IM |
382 | /* |
383 | * Mark the end of the wait period if dequeueing a | |
384 | * waiting task: | |
385 | */ | |
429d43bc | 386 | if (se != cfs_rq->curr) |
9ef0a961 | 387 | update_stats_wait_end(cfs_rq, se); |
bf0f6f24 IM |
388 | } |
389 | ||
390 | /* | |
391 | * We are picking a new current task - update its stats: | |
392 | */ | |
393 | static inline void | |
79303e9e | 394 | update_stats_curr_start(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 IM |
395 | { |
396 | /* | |
397 | * We are starting a new run period: | |
398 | */ | |
d281918d | 399 | se->exec_start = rq_of(cfs_rq)->clock; |
bf0f6f24 IM |
400 | } |
401 | ||
bf0f6f24 IM |
402 | /************************************************** |
403 | * Scheduling class queueing methods: | |
404 | */ | |
405 | ||
30cfdcfc DA |
406 | static void |
407 | account_entity_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se) | |
408 | { | |
409 | update_load_add(&cfs_rq->load, se->load.weight); | |
410 | cfs_rq->nr_running++; | |
411 | se->on_rq = 1; | |
412 | } | |
413 | ||
414 | static void | |
415 | account_entity_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se) | |
416 | { | |
417 | update_load_sub(&cfs_rq->load, se->load.weight); | |
418 | cfs_rq->nr_running--; | |
419 | se->on_rq = 0; | |
420 | } | |
421 | ||
2396af69 | 422 | static void enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 423 | { |
bf0f6f24 IM |
424 | #ifdef CONFIG_SCHEDSTATS |
425 | if (se->sleep_start) { | |
d281918d | 426 | u64 delta = rq_of(cfs_rq)->clock - se->sleep_start; |
9745512c | 427 | struct task_struct *tsk = task_of(se); |
bf0f6f24 IM |
428 | |
429 | if ((s64)delta < 0) | |
430 | delta = 0; | |
431 | ||
432 | if (unlikely(delta > se->sleep_max)) | |
433 | se->sleep_max = delta; | |
434 | ||
435 | se->sleep_start = 0; | |
436 | se->sum_sleep_runtime += delta; | |
9745512c AV |
437 | |
438 | account_scheduler_latency(tsk, delta >> 10, 1); | |
bf0f6f24 IM |
439 | } |
440 | if (se->block_start) { | |
d281918d | 441 | u64 delta = rq_of(cfs_rq)->clock - se->block_start; |
9745512c | 442 | struct task_struct *tsk = task_of(se); |
bf0f6f24 IM |
443 | |
444 | if ((s64)delta < 0) | |
445 | delta = 0; | |
446 | ||
447 | if (unlikely(delta > se->block_max)) | |
448 | se->block_max = delta; | |
449 | ||
450 | se->block_start = 0; | |
451 | se->sum_sleep_runtime += delta; | |
30084fbd IM |
452 | |
453 | /* | |
454 | * Blocking time is in units of nanosecs, so shift by 20 to | |
455 | * get a milliseconds-range estimation of the amount of | |
456 | * time that the task spent sleeping: | |
457 | */ | |
458 | if (unlikely(prof_on == SLEEP_PROFILING)) { | |
e22f5bbf | 459 | |
30084fbd IM |
460 | profile_hits(SLEEP_PROFILING, (void *)get_wchan(tsk), |
461 | delta >> 20); | |
462 | } | |
9745512c | 463 | account_scheduler_latency(tsk, delta >> 10, 0); |
bf0f6f24 IM |
464 | } |
465 | #endif | |
466 | } | |
467 | ||
ddc97297 PZ |
468 | static void check_spread(struct cfs_rq *cfs_rq, struct sched_entity *se) |
469 | { | |
470 | #ifdef CONFIG_SCHED_DEBUG | |
471 | s64 d = se->vruntime - cfs_rq->min_vruntime; | |
472 | ||
473 | if (d < 0) | |
474 | d = -d; | |
475 | ||
476 | if (d > 3*sysctl_sched_latency) | |
477 | schedstat_inc(cfs_rq, nr_spread_over); | |
478 | #endif | |
479 | } | |
480 | ||
aeb73b04 PZ |
481 | static void |
482 | place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial) | |
483 | { | |
67e9fb2a | 484 | u64 vruntime; |
aeb73b04 | 485 | |
3fe69747 PZ |
486 | if (first_fair(cfs_rq)) { |
487 | vruntime = min_vruntime(cfs_rq->min_vruntime, | |
488 | __pick_next_entity(cfs_rq)->vruntime); | |
489 | } else | |
490 | vruntime = cfs_rq->min_vruntime; | |
94dfb5e7 | 491 | |
2cb8600e PZ |
492 | /* |
493 | * The 'current' period is already promised to the current tasks, | |
494 | * however the extra weight of the new task will slow them down a | |
495 | * little, place the new task so that it fits in the slot that | |
496 | * stays open at the end. | |
497 | */ | |
94dfb5e7 | 498 | if (initial && sched_feat(START_DEBIT)) |
647e7cac | 499 | vruntime += sched_vslice_add(cfs_rq, se); |
aeb73b04 | 500 | |
8465e792 | 501 | if (!initial) { |
2cb8600e | 502 | /* sleeps upto a single latency don't count. */ |
018d6db4 IM |
503 | if (sched_feat(NEW_FAIR_SLEEPERS)) { |
504 | vruntime -= calc_delta_fair(sysctl_sched_latency, | |
505 | &cfs_rq->load); | |
506 | } | |
94359f05 | 507 | |
2cb8600e PZ |
508 | /* ensure we never gain time by being placed backwards. */ |
509 | vruntime = max_vruntime(se->vruntime, vruntime); | |
aeb73b04 PZ |
510 | } |
511 | ||
67e9fb2a | 512 | se->vruntime = vruntime; |
aeb73b04 PZ |
513 | } |
514 | ||
bf0f6f24 | 515 | static void |
83b699ed | 516 | enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int wakeup) |
bf0f6f24 IM |
517 | { |
518 | /* | |
a2a2d680 | 519 | * Update run-time statistics of the 'current'. |
bf0f6f24 | 520 | */ |
b7cc0896 | 521 | update_curr(cfs_rq); |
bf0f6f24 | 522 | |
e9acbff6 | 523 | if (wakeup) { |
aeb73b04 | 524 | place_entity(cfs_rq, se, 0); |
2396af69 | 525 | enqueue_sleeper(cfs_rq, se); |
e9acbff6 | 526 | } |
bf0f6f24 | 527 | |
d2417e5a | 528 | update_stats_enqueue(cfs_rq, se); |
ddc97297 | 529 | check_spread(cfs_rq, se); |
83b699ed SV |
530 | if (se != cfs_rq->curr) |
531 | __enqueue_entity(cfs_rq, se); | |
30cfdcfc | 532 | account_entity_enqueue(cfs_rq, se); |
bf0f6f24 IM |
533 | } |
534 | ||
4ae7d5ce IM |
535 | static void update_avg(u64 *avg, u64 sample) |
536 | { | |
537 | s64 diff = sample - *avg; | |
538 | *avg += diff >> 3; | |
539 | } | |
540 | ||
541 | static void update_avg_stats(struct cfs_rq *cfs_rq, struct sched_entity *se) | |
542 | { | |
543 | if (!se->last_wakeup) | |
544 | return; | |
545 | ||
546 | update_avg(&se->avg_overlap, se->sum_exec_runtime - se->last_wakeup); | |
547 | se->last_wakeup = 0; | |
548 | } | |
549 | ||
bf0f6f24 | 550 | static void |
525c2716 | 551 | dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int sleep) |
bf0f6f24 | 552 | { |
a2a2d680 DA |
553 | /* |
554 | * Update run-time statistics of the 'current'. | |
555 | */ | |
556 | update_curr(cfs_rq); | |
557 | ||
19b6a2e3 | 558 | update_stats_dequeue(cfs_rq, se); |
db36cc7d | 559 | if (sleep) { |
4ae7d5ce | 560 | update_avg_stats(cfs_rq, se); |
67e9fb2a | 561 | #ifdef CONFIG_SCHEDSTATS |
bf0f6f24 IM |
562 | if (entity_is_task(se)) { |
563 | struct task_struct *tsk = task_of(se); | |
564 | ||
565 | if (tsk->state & TASK_INTERRUPTIBLE) | |
d281918d | 566 | se->sleep_start = rq_of(cfs_rq)->clock; |
bf0f6f24 | 567 | if (tsk->state & TASK_UNINTERRUPTIBLE) |
d281918d | 568 | se->block_start = rq_of(cfs_rq)->clock; |
bf0f6f24 | 569 | } |
db36cc7d | 570 | #endif |
67e9fb2a PZ |
571 | } |
572 | ||
83b699ed | 573 | if (se != cfs_rq->curr) |
30cfdcfc DA |
574 | __dequeue_entity(cfs_rq, se); |
575 | account_entity_dequeue(cfs_rq, se); | |
bf0f6f24 IM |
576 | } |
577 | ||
578 | /* | |
579 | * Preempt the current task with a newly woken task if needed: | |
580 | */ | |
7c92e54f | 581 | static void |
2e09bf55 | 582 | check_preempt_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr) |
bf0f6f24 | 583 | { |
11697830 PZ |
584 | unsigned long ideal_runtime, delta_exec; |
585 | ||
6d0f0ebd | 586 | ideal_runtime = sched_slice(cfs_rq, curr); |
11697830 | 587 | delta_exec = curr->sum_exec_runtime - curr->prev_sum_exec_runtime; |
3e3e13f3 | 588 | if (delta_exec > ideal_runtime) |
bf0f6f24 IM |
589 | resched_task(rq_of(cfs_rq)->curr); |
590 | } | |
591 | ||
83b699ed | 592 | static void |
8494f412 | 593 | set_next_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 594 | { |
83b699ed SV |
595 | /* 'current' is not kept within the tree. */ |
596 | if (se->on_rq) { | |
597 | /* | |
598 | * Any task has to be enqueued before it get to execute on | |
599 | * a CPU. So account for the time it spent waiting on the | |
600 | * runqueue. | |
601 | */ | |
602 | update_stats_wait_end(cfs_rq, se); | |
603 | __dequeue_entity(cfs_rq, se); | |
604 | } | |
605 | ||
79303e9e | 606 | update_stats_curr_start(cfs_rq, se); |
429d43bc | 607 | cfs_rq->curr = se; |
eba1ed4b IM |
608 | #ifdef CONFIG_SCHEDSTATS |
609 | /* | |
610 | * Track our maximum slice length, if the CPU's load is at | |
611 | * least twice that of our own weight (i.e. dont track it | |
612 | * when there are only lesser-weight tasks around): | |
613 | */ | |
495eca49 | 614 | if (rq_of(cfs_rq)->load.weight >= 2*se->load.weight) { |
eba1ed4b IM |
615 | se->slice_max = max(se->slice_max, |
616 | se->sum_exec_runtime - se->prev_sum_exec_runtime); | |
617 | } | |
618 | #endif | |
4a55b450 | 619 | se->prev_sum_exec_runtime = se->sum_exec_runtime; |
bf0f6f24 IM |
620 | } |
621 | ||
0bbd3336 PZ |
622 | static int |
623 | wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se); | |
624 | ||
aa2ac252 PZ |
625 | static struct sched_entity * |
626 | pick_next(struct cfs_rq *cfs_rq, struct sched_entity *se) | |
627 | { | |
aa2ac252 PZ |
628 | if (!cfs_rq->next) |
629 | return se; | |
630 | ||
0bbd3336 | 631 | if (wakeup_preempt_entity(cfs_rq->next, se) != 0) |
aa2ac252 PZ |
632 | return se; |
633 | ||
634 | return cfs_rq->next; | |
635 | } | |
636 | ||
9948f4b2 | 637 | static struct sched_entity *pick_next_entity(struct cfs_rq *cfs_rq) |
bf0f6f24 | 638 | { |
08ec3df5 | 639 | struct sched_entity *se = NULL; |
bf0f6f24 | 640 | |
08ec3df5 DA |
641 | if (first_fair(cfs_rq)) { |
642 | se = __pick_next_entity(cfs_rq); | |
aa2ac252 | 643 | se = pick_next(cfs_rq, se); |
08ec3df5 DA |
644 | set_next_entity(cfs_rq, se); |
645 | } | |
bf0f6f24 IM |
646 | |
647 | return se; | |
648 | } | |
649 | ||
ab6cde26 | 650 | static void put_prev_entity(struct cfs_rq *cfs_rq, struct sched_entity *prev) |
bf0f6f24 IM |
651 | { |
652 | /* | |
653 | * If still on the runqueue then deactivate_task() | |
654 | * was not called and update_curr() has to be done: | |
655 | */ | |
656 | if (prev->on_rq) | |
b7cc0896 | 657 | update_curr(cfs_rq); |
bf0f6f24 | 658 | |
ddc97297 | 659 | check_spread(cfs_rq, prev); |
30cfdcfc | 660 | if (prev->on_rq) { |
5870db5b | 661 | update_stats_wait_start(cfs_rq, prev); |
30cfdcfc DA |
662 | /* Put 'current' back into the tree. */ |
663 | __enqueue_entity(cfs_rq, prev); | |
664 | } | |
429d43bc | 665 | cfs_rq->curr = NULL; |
bf0f6f24 IM |
666 | } |
667 | ||
8f4d37ec PZ |
668 | static void |
669 | entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr, int queued) | |
bf0f6f24 | 670 | { |
bf0f6f24 | 671 | /* |
30cfdcfc | 672 | * Update run-time statistics of the 'current'. |
bf0f6f24 | 673 | */ |
30cfdcfc | 674 | update_curr(cfs_rq); |
bf0f6f24 | 675 | |
8f4d37ec PZ |
676 | #ifdef CONFIG_SCHED_HRTICK |
677 | /* | |
678 | * queued ticks are scheduled to match the slice, so don't bother | |
679 | * validating it and just reschedule. | |
680 | */ | |
681 | if (queued) | |
682 | return resched_task(rq_of(cfs_rq)->curr); | |
683 | /* | |
684 | * don't let the period tick interfere with the hrtick preemption | |
685 | */ | |
686 | if (!sched_feat(DOUBLE_TICK) && | |
687 | hrtimer_active(&rq_of(cfs_rq)->hrtick_timer)) | |
688 | return; | |
689 | #endif | |
690 | ||
ce6c1311 | 691 | if (cfs_rq->nr_running > 1 || !sched_feat(WAKEUP_PREEMPT)) |
2e09bf55 | 692 | check_preempt_tick(cfs_rq, curr); |
bf0f6f24 IM |
693 | } |
694 | ||
695 | /************************************************** | |
696 | * CFS operations on tasks: | |
697 | */ | |
698 | ||
699 | #ifdef CONFIG_FAIR_GROUP_SCHED | |
700 | ||
701 | /* Walk up scheduling entities hierarchy */ | |
702 | #define for_each_sched_entity(se) \ | |
703 | for (; se; se = se->parent) | |
704 | ||
705 | static inline struct cfs_rq *task_cfs_rq(struct task_struct *p) | |
706 | { | |
707 | return p->se.cfs_rq; | |
708 | } | |
709 | ||
710 | /* runqueue on which this entity is (to be) queued */ | |
711 | static inline struct cfs_rq *cfs_rq_of(struct sched_entity *se) | |
712 | { | |
713 | return se->cfs_rq; | |
714 | } | |
715 | ||
716 | /* runqueue "owned" by this group */ | |
717 | static inline struct cfs_rq *group_cfs_rq(struct sched_entity *grp) | |
718 | { | |
719 | return grp->my_q; | |
720 | } | |
721 | ||
722 | /* Given a group's cfs_rq on one cpu, return its corresponding cfs_rq on | |
723 | * another cpu ('this_cpu') | |
724 | */ | |
725 | static inline struct cfs_rq *cpu_cfs_rq(struct cfs_rq *cfs_rq, int this_cpu) | |
726 | { | |
29f59db3 | 727 | return cfs_rq->tg->cfs_rq[this_cpu]; |
bf0f6f24 IM |
728 | } |
729 | ||
730 | /* Iterate thr' all leaf cfs_rq's on a runqueue */ | |
731 | #define for_each_leaf_cfs_rq(rq, cfs_rq) \ | |
ec2c507f | 732 | list_for_each_entry_rcu(cfs_rq, &rq->leaf_cfs_rq_list, leaf_cfs_rq_list) |
bf0f6f24 | 733 | |
fad095a7 SV |
734 | /* Do the two (enqueued) entities belong to the same group ? */ |
735 | static inline int | |
736 | is_same_group(struct sched_entity *se, struct sched_entity *pse) | |
bf0f6f24 | 737 | { |
fad095a7 | 738 | if (se->cfs_rq == pse->cfs_rq) |
bf0f6f24 IM |
739 | return 1; |
740 | ||
741 | return 0; | |
742 | } | |
743 | ||
fad095a7 SV |
744 | static inline struct sched_entity *parent_entity(struct sched_entity *se) |
745 | { | |
746 | return se->parent; | |
747 | } | |
748 | ||
bf0f6f24 IM |
749 | #else /* CONFIG_FAIR_GROUP_SCHED */ |
750 | ||
751 | #define for_each_sched_entity(se) \ | |
752 | for (; se; se = NULL) | |
753 | ||
754 | static inline struct cfs_rq *task_cfs_rq(struct task_struct *p) | |
755 | { | |
756 | return &task_rq(p)->cfs; | |
757 | } | |
758 | ||
759 | static inline struct cfs_rq *cfs_rq_of(struct sched_entity *se) | |
760 | { | |
761 | struct task_struct *p = task_of(se); | |
762 | struct rq *rq = task_rq(p); | |
763 | ||
764 | return &rq->cfs; | |
765 | } | |
766 | ||
767 | /* runqueue "owned" by this group */ | |
768 | static inline struct cfs_rq *group_cfs_rq(struct sched_entity *grp) | |
769 | { | |
770 | return NULL; | |
771 | } | |
772 | ||
773 | static inline struct cfs_rq *cpu_cfs_rq(struct cfs_rq *cfs_rq, int this_cpu) | |
774 | { | |
775 | return &cpu_rq(this_cpu)->cfs; | |
776 | } | |
777 | ||
778 | #define for_each_leaf_cfs_rq(rq, cfs_rq) \ | |
779 | for (cfs_rq = &rq->cfs; cfs_rq; cfs_rq = NULL) | |
780 | ||
fad095a7 SV |
781 | static inline int |
782 | is_same_group(struct sched_entity *se, struct sched_entity *pse) | |
bf0f6f24 IM |
783 | { |
784 | return 1; | |
785 | } | |
786 | ||
fad095a7 SV |
787 | static inline struct sched_entity *parent_entity(struct sched_entity *se) |
788 | { | |
789 | return NULL; | |
790 | } | |
791 | ||
bf0f6f24 IM |
792 | #endif /* CONFIG_FAIR_GROUP_SCHED */ |
793 | ||
8f4d37ec PZ |
794 | #ifdef CONFIG_SCHED_HRTICK |
795 | static void hrtick_start_fair(struct rq *rq, struct task_struct *p) | |
796 | { | |
797 | int requeue = rq->curr == p; | |
798 | struct sched_entity *se = &p->se; | |
799 | struct cfs_rq *cfs_rq = cfs_rq_of(se); | |
800 | ||
801 | WARN_ON(task_rq(p) != rq); | |
802 | ||
803 | if (hrtick_enabled(rq) && cfs_rq->nr_running > 1) { | |
804 | u64 slice = sched_slice(cfs_rq, se); | |
805 | u64 ran = se->sum_exec_runtime - se->prev_sum_exec_runtime; | |
806 | s64 delta = slice - ran; | |
807 | ||
808 | if (delta < 0) { | |
809 | if (rq->curr == p) | |
810 | resched_task(p); | |
811 | return; | |
812 | } | |
813 | ||
814 | /* | |
815 | * Don't schedule slices shorter than 10000ns, that just | |
816 | * doesn't make sense. Rely on vruntime for fairness. | |
817 | */ | |
818 | if (!requeue) | |
819 | delta = max(10000LL, delta); | |
820 | ||
821 | hrtick_start(rq, delta, requeue); | |
822 | } | |
823 | } | |
824 | #else | |
825 | static inline void | |
826 | hrtick_start_fair(struct rq *rq, struct task_struct *p) | |
827 | { | |
828 | } | |
829 | #endif | |
830 | ||
bf0f6f24 IM |
831 | /* |
832 | * The enqueue_task method is called before nr_running is | |
833 | * increased. Here we update the fair scheduling stats and | |
834 | * then put the task into the rbtree: | |
835 | */ | |
fd390f6a | 836 | static void enqueue_task_fair(struct rq *rq, struct task_struct *p, int wakeup) |
bf0f6f24 IM |
837 | { |
838 | struct cfs_rq *cfs_rq; | |
62fb1851 | 839 | struct sched_entity *se = &p->se; |
bf0f6f24 IM |
840 | |
841 | for_each_sched_entity(se) { | |
62fb1851 | 842 | if (se->on_rq) |
bf0f6f24 IM |
843 | break; |
844 | cfs_rq = cfs_rq_of(se); | |
83b699ed | 845 | enqueue_entity(cfs_rq, se, wakeup); |
b9fa3df3 | 846 | wakeup = 1; |
bf0f6f24 | 847 | } |
8f4d37ec PZ |
848 | |
849 | hrtick_start_fair(rq, rq->curr); | |
bf0f6f24 IM |
850 | } |
851 | ||
852 | /* | |
853 | * The dequeue_task method is called before nr_running is | |
854 | * decreased. We remove the task from the rbtree and | |
855 | * update the fair scheduling stats: | |
856 | */ | |
f02231e5 | 857 | static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int sleep) |
bf0f6f24 IM |
858 | { |
859 | struct cfs_rq *cfs_rq; | |
62fb1851 | 860 | struct sched_entity *se = &p->se; |
bf0f6f24 IM |
861 | |
862 | for_each_sched_entity(se) { | |
863 | cfs_rq = cfs_rq_of(se); | |
525c2716 | 864 | dequeue_entity(cfs_rq, se, sleep); |
bf0f6f24 | 865 | /* Don't dequeue parent if it has other entities besides us */ |
62fb1851 | 866 | if (cfs_rq->load.weight) |
bf0f6f24 | 867 | break; |
b9fa3df3 | 868 | sleep = 1; |
bf0f6f24 | 869 | } |
8f4d37ec PZ |
870 | |
871 | hrtick_start_fair(rq, rq->curr); | |
bf0f6f24 IM |
872 | } |
873 | ||
874 | /* | |
1799e35d IM |
875 | * sched_yield() support is very simple - we dequeue and enqueue. |
876 | * | |
877 | * If compat_yield is turned on then we requeue to the end of the tree. | |
bf0f6f24 | 878 | */ |
4530d7ab | 879 | static void yield_task_fair(struct rq *rq) |
bf0f6f24 | 880 | { |
db292ca3 IM |
881 | struct task_struct *curr = rq->curr; |
882 | struct cfs_rq *cfs_rq = task_cfs_rq(curr); | |
883 | struct sched_entity *rightmost, *se = &curr->se; | |
bf0f6f24 IM |
884 | |
885 | /* | |
1799e35d IM |
886 | * Are we the only task in the tree? |
887 | */ | |
888 | if (unlikely(cfs_rq->nr_running == 1)) | |
889 | return; | |
890 | ||
db292ca3 | 891 | if (likely(!sysctl_sched_compat_yield) && curr->policy != SCHED_BATCH) { |
1799e35d IM |
892 | __update_rq_clock(rq); |
893 | /* | |
a2a2d680 | 894 | * Update run-time statistics of the 'current'. |
1799e35d | 895 | */ |
2b1e315d | 896 | update_curr(cfs_rq); |
1799e35d IM |
897 | |
898 | return; | |
899 | } | |
900 | /* | |
901 | * Find the rightmost entry in the rbtree: | |
bf0f6f24 | 902 | */ |
2b1e315d | 903 | rightmost = __pick_last_entity(cfs_rq); |
1799e35d IM |
904 | /* |
905 | * Already in the rightmost position? | |
906 | */ | |
2b1e315d | 907 | if (unlikely(rightmost->vruntime < se->vruntime)) |
1799e35d IM |
908 | return; |
909 | ||
910 | /* | |
911 | * Minimally necessary key value to be last in the tree: | |
2b1e315d DA |
912 | * Upon rescheduling, sched_class::put_prev_task() will place |
913 | * 'current' within the tree based on its new key value. | |
1799e35d | 914 | */ |
30cfdcfc | 915 | se->vruntime = rightmost->vruntime + 1; |
bf0f6f24 IM |
916 | } |
917 | ||
e7693a36 GH |
918 | /* |
919 | * wake_idle() will wake a task on an idle cpu if task->cpu is | |
920 | * not idle and an idle cpu is available. The span of cpus to | |
921 | * search starts with cpus closest then further out as needed, | |
922 | * so we always favor a closer, idle cpu. | |
923 | * | |
924 | * Returns the CPU we should wake onto. | |
925 | */ | |
926 | #if defined(ARCH_HAS_SCHED_WAKE_IDLE) | |
927 | static int wake_idle(int cpu, struct task_struct *p) | |
928 | { | |
929 | cpumask_t tmp; | |
930 | struct sched_domain *sd; | |
931 | int i; | |
932 | ||
933 | /* | |
934 | * If it is idle, then it is the best cpu to run this task. | |
935 | * | |
936 | * This cpu is also the best, if it has more than one task already. | |
937 | * Siblings must be also busy(in most cases) as they didn't already | |
938 | * pickup the extra load from this cpu and hence we need not check | |
939 | * sibling runqueue info. This will avoid the checks and cache miss | |
940 | * penalities associated with that. | |
941 | */ | |
942 | if (idle_cpu(cpu) || cpu_rq(cpu)->nr_running > 1) | |
943 | return cpu; | |
944 | ||
945 | for_each_domain(cpu, sd) { | |
946 | if (sd->flags & SD_WAKE_IDLE) { | |
947 | cpus_and(tmp, sd->span, p->cpus_allowed); | |
948 | for_each_cpu_mask(i, tmp) { | |
949 | if (idle_cpu(i)) { | |
950 | if (i != task_cpu(p)) { | |
951 | schedstat_inc(p, | |
952 | se.nr_wakeups_idle); | |
953 | } | |
954 | return i; | |
955 | } | |
956 | } | |
957 | } else { | |
958 | break; | |
959 | } | |
960 | } | |
961 | return cpu; | |
962 | } | |
963 | #else | |
964 | static inline int wake_idle(int cpu, struct task_struct *p) | |
965 | { | |
966 | return cpu; | |
967 | } | |
968 | #endif | |
969 | ||
970 | #ifdef CONFIG_SMP | |
098fb9db | 971 | |
4ae7d5ce IM |
972 | static const struct sched_class fair_sched_class; |
973 | ||
098fb9db | 974 | static int |
4ae7d5ce IM |
975 | wake_affine(struct rq *rq, struct sched_domain *this_sd, struct rq *this_rq, |
976 | struct task_struct *p, int prev_cpu, int this_cpu, int sync, | |
977 | int idx, unsigned long load, unsigned long this_load, | |
098fb9db IM |
978 | unsigned int imbalance) |
979 | { | |
4ae7d5ce | 980 | struct task_struct *curr = this_rq->curr; |
098fb9db IM |
981 | unsigned long tl = this_load; |
982 | unsigned long tl_per_task; | |
983 | ||
984 | if (!(this_sd->flags & SD_WAKE_AFFINE)) | |
985 | return 0; | |
986 | ||
987 | /* | |
4ae7d5ce IM |
988 | * If the currently running task will sleep within |
989 | * a reasonable amount of time then attract this newly | |
990 | * woken task: | |
098fb9db | 991 | */ |
4ae7d5ce IM |
992 | if (sync && curr->sched_class == &fair_sched_class) { |
993 | if (curr->se.avg_overlap < sysctl_sched_migration_cost && | |
994 | p->se.avg_overlap < sysctl_sched_migration_cost) | |
995 | return 1; | |
996 | } | |
098fb9db IM |
997 | |
998 | schedstat_inc(p, se.nr_wakeups_affine_attempts); | |
999 | tl_per_task = cpu_avg_load_per_task(this_cpu); | |
1000 | ||
1001 | /* | |
1002 | * If sync wakeup then subtract the (maximum possible) | |
1003 | * effect of the currently running task from the load | |
1004 | * of the current CPU: | |
1005 | */ | |
1006 | if (sync) | |
1007 | tl -= current->se.load.weight; | |
1008 | ||
ac192d39 | 1009 | if ((tl <= load && tl + target_load(prev_cpu, idx) <= tl_per_task) || |
098fb9db IM |
1010 | 100*(tl + p->se.load.weight) <= imbalance*load) { |
1011 | /* | |
1012 | * This domain has SD_WAKE_AFFINE and | |
1013 | * p is cache cold in this domain, and | |
1014 | * there is no bad imbalance. | |
1015 | */ | |
1016 | schedstat_inc(this_sd, ttwu_move_affine); | |
1017 | schedstat_inc(p, se.nr_wakeups_affine); | |
1018 | ||
1019 | return 1; | |
1020 | } | |
1021 | return 0; | |
1022 | } | |
1023 | ||
e7693a36 GH |
1024 | static int select_task_rq_fair(struct task_struct *p, int sync) |
1025 | { | |
e7693a36 | 1026 | struct sched_domain *sd, *this_sd = NULL; |
ac192d39 | 1027 | int prev_cpu, this_cpu, new_cpu; |
098fb9db | 1028 | unsigned long load, this_load; |
4ae7d5ce | 1029 | struct rq *rq, *this_rq; |
098fb9db | 1030 | unsigned int imbalance; |
098fb9db | 1031 | int idx; |
e7693a36 | 1032 | |
ac192d39 IM |
1033 | prev_cpu = task_cpu(p); |
1034 | rq = task_rq(p); | |
1035 | this_cpu = smp_processor_id(); | |
4ae7d5ce | 1036 | this_rq = cpu_rq(this_cpu); |
ac192d39 | 1037 | new_cpu = prev_cpu; |
e7693a36 | 1038 | |
ac192d39 IM |
1039 | /* |
1040 | * 'this_sd' is the first domain that both | |
1041 | * this_cpu and prev_cpu are present in: | |
1042 | */ | |
e7693a36 | 1043 | for_each_domain(this_cpu, sd) { |
ac192d39 | 1044 | if (cpu_isset(prev_cpu, sd->span)) { |
e7693a36 GH |
1045 | this_sd = sd; |
1046 | break; | |
1047 | } | |
1048 | } | |
1049 | ||
1050 | if (unlikely(!cpu_isset(this_cpu, p->cpus_allowed))) | |
f4827386 | 1051 | goto out; |
e7693a36 GH |
1052 | |
1053 | /* | |
1054 | * Check for affine wakeup and passive balancing possibilities. | |
1055 | */ | |
098fb9db | 1056 | if (!this_sd) |
f4827386 | 1057 | goto out; |
e7693a36 | 1058 | |
098fb9db IM |
1059 | idx = this_sd->wake_idx; |
1060 | ||
1061 | imbalance = 100 + (this_sd->imbalance_pct - 100) / 2; | |
1062 | ||
ac192d39 | 1063 | load = source_load(prev_cpu, idx); |
098fb9db IM |
1064 | this_load = target_load(this_cpu, idx); |
1065 | ||
4ae7d5ce IM |
1066 | if (wake_affine(rq, this_sd, this_rq, p, prev_cpu, this_cpu, sync, idx, |
1067 | load, this_load, imbalance)) | |
1068 | return this_cpu; | |
1069 | ||
1070 | if (prev_cpu == this_cpu) | |
f4827386 | 1071 | goto out; |
098fb9db IM |
1072 | |
1073 | /* | |
1074 | * Start passive balancing when half the imbalance_pct | |
1075 | * limit is reached. | |
1076 | */ | |
1077 | if (this_sd->flags & SD_WAKE_BALANCE) { | |
1078 | if (imbalance*this_load <= 100*load) { | |
1079 | schedstat_inc(this_sd, ttwu_move_balance); | |
1080 | schedstat_inc(p, se.nr_wakeups_passive); | |
4ae7d5ce | 1081 | return this_cpu; |
e7693a36 GH |
1082 | } |
1083 | } | |
1084 | ||
f4827386 | 1085 | out: |
e7693a36 GH |
1086 | return wake_idle(new_cpu, p); |
1087 | } | |
1088 | #endif /* CONFIG_SMP */ | |
1089 | ||
0bbd3336 PZ |
1090 | static unsigned long wakeup_gran(struct sched_entity *se) |
1091 | { | |
1092 | unsigned long gran = sysctl_sched_wakeup_granularity; | |
1093 | ||
1094 | /* | |
1095 | * More easily preempt - nice tasks, while not making | |
1096 | * it harder for + nice tasks. | |
1097 | */ | |
1098 | if (unlikely(se->load.weight > NICE_0_LOAD)) | |
1099 | gran = calc_delta_fair(gran, &se->load); | |
1100 | ||
1101 | return gran; | |
1102 | } | |
1103 | ||
1104 | /* | |
1105 | * Should 'se' preempt 'curr'. | |
1106 | * | |
1107 | * |s1 | |
1108 | * |s2 | |
1109 | * |s3 | |
1110 | * g | |
1111 | * |<--->|c | |
1112 | * | |
1113 | * w(c, s1) = -1 | |
1114 | * w(c, s2) = 0 | |
1115 | * w(c, s3) = 1 | |
1116 | * | |
1117 | */ | |
1118 | static int | |
1119 | wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se) | |
1120 | { | |
1121 | s64 gran, vdiff = curr->vruntime - se->vruntime; | |
1122 | ||
1123 | if (vdiff < 0) | |
1124 | return -1; | |
1125 | ||
1126 | gran = wakeup_gran(curr); | |
1127 | if (vdiff > gran) | |
1128 | return 1; | |
1129 | ||
1130 | return 0; | |
1131 | } | |
e7693a36 | 1132 | |
bf0f6f24 IM |
1133 | /* |
1134 | * Preempt the current task with a newly woken task if needed: | |
1135 | */ | |
2e09bf55 | 1136 | static void check_preempt_wakeup(struct rq *rq, struct task_struct *p) |
bf0f6f24 IM |
1137 | { |
1138 | struct task_struct *curr = rq->curr; | |
fad095a7 | 1139 | struct cfs_rq *cfs_rq = task_cfs_rq(curr); |
8651a86c | 1140 | struct sched_entity *se = &curr->se, *pse = &p->se; |
bf0f6f24 IM |
1141 | |
1142 | if (unlikely(rt_prio(p->prio))) { | |
a8e504d2 | 1143 | update_rq_clock(rq); |
b7cc0896 | 1144 | update_curr(cfs_rq); |
bf0f6f24 IM |
1145 | resched_task(curr); |
1146 | return; | |
1147 | } | |
aa2ac252 | 1148 | |
4ae7d5ce IM |
1149 | se->last_wakeup = se->sum_exec_runtime; |
1150 | if (unlikely(se == pse)) | |
1151 | return; | |
1152 | ||
aa2ac252 PZ |
1153 | cfs_rq_of(pse)->next = pse; |
1154 | ||
91c234b4 IM |
1155 | /* |
1156 | * Batch tasks do not preempt (their preemption is driven by | |
1157 | * the tick): | |
1158 | */ | |
1159 | if (unlikely(p->policy == SCHED_BATCH)) | |
1160 | return; | |
bf0f6f24 | 1161 | |
77d9cc44 IM |
1162 | if (!sched_feat(WAKEUP_PREEMPT)) |
1163 | return; | |
8651a86c | 1164 | |
77d9cc44 IM |
1165 | while (!is_same_group(se, pse)) { |
1166 | se = parent_entity(se); | |
1167 | pse = parent_entity(pse); | |
ce6c1311 | 1168 | } |
77d9cc44 | 1169 | |
0bbd3336 | 1170 | if (wakeup_preempt_entity(se, pse) == 1) |
77d9cc44 | 1171 | resched_task(curr); |
bf0f6f24 IM |
1172 | } |
1173 | ||
fb8d4724 | 1174 | static struct task_struct *pick_next_task_fair(struct rq *rq) |
bf0f6f24 | 1175 | { |
8f4d37ec | 1176 | struct task_struct *p; |
bf0f6f24 IM |
1177 | struct cfs_rq *cfs_rq = &rq->cfs; |
1178 | struct sched_entity *se; | |
1179 | ||
1180 | if (unlikely(!cfs_rq->nr_running)) | |
1181 | return NULL; | |
1182 | ||
1183 | do { | |
9948f4b2 | 1184 | se = pick_next_entity(cfs_rq); |
bf0f6f24 IM |
1185 | cfs_rq = group_cfs_rq(se); |
1186 | } while (cfs_rq); | |
1187 | ||
8f4d37ec PZ |
1188 | p = task_of(se); |
1189 | hrtick_start_fair(rq, p); | |
1190 | ||
1191 | return p; | |
bf0f6f24 IM |
1192 | } |
1193 | ||
1194 | /* | |
1195 | * Account for a descheduled task: | |
1196 | */ | |
31ee529c | 1197 | static void put_prev_task_fair(struct rq *rq, struct task_struct *prev) |
bf0f6f24 IM |
1198 | { |
1199 | struct sched_entity *se = &prev->se; | |
1200 | struct cfs_rq *cfs_rq; | |
1201 | ||
1202 | for_each_sched_entity(se) { | |
1203 | cfs_rq = cfs_rq_of(se); | |
ab6cde26 | 1204 | put_prev_entity(cfs_rq, se); |
bf0f6f24 IM |
1205 | } |
1206 | } | |
1207 | ||
681f3e68 | 1208 | #ifdef CONFIG_SMP |
bf0f6f24 IM |
1209 | /************************************************** |
1210 | * Fair scheduling class load-balancing methods: | |
1211 | */ | |
1212 | ||
1213 | /* | |
1214 | * Load-balancing iterator. Note: while the runqueue stays locked | |
1215 | * during the whole iteration, the current task might be | |
1216 | * dequeued so the iterator has to be dequeue-safe. Here we | |
1217 | * achieve that by always pre-iterating before returning | |
1218 | * the current task: | |
1219 | */ | |
a9957449 | 1220 | static struct task_struct * |
bf0f6f24 IM |
1221 | __load_balance_iterator(struct cfs_rq *cfs_rq, struct rb_node *curr) |
1222 | { | |
1223 | struct task_struct *p; | |
1224 | ||
1225 | if (!curr) | |
1226 | return NULL; | |
1227 | ||
1228 | p = rb_entry(curr, struct task_struct, se.run_node); | |
1229 | cfs_rq->rb_load_balance_curr = rb_next(curr); | |
1230 | ||
1231 | return p; | |
1232 | } | |
1233 | ||
1234 | static struct task_struct *load_balance_start_fair(void *arg) | |
1235 | { | |
1236 | struct cfs_rq *cfs_rq = arg; | |
1237 | ||
1238 | return __load_balance_iterator(cfs_rq, first_fair(cfs_rq)); | |
1239 | } | |
1240 | ||
1241 | static struct task_struct *load_balance_next_fair(void *arg) | |
1242 | { | |
1243 | struct cfs_rq *cfs_rq = arg; | |
1244 | ||
1245 | return __load_balance_iterator(cfs_rq, cfs_rq->rb_load_balance_curr); | |
1246 | } | |
1247 | ||
62fb1851 PZ |
1248 | #ifdef CONFIG_FAIR_GROUP_SCHED |
1249 | static int cfs_rq_best_prio(struct cfs_rq *cfs_rq) | |
1250 | { | |
1251 | struct sched_entity *curr; | |
1252 | struct task_struct *p; | |
1253 | ||
1254 | if (!cfs_rq->nr_running || !first_fair(cfs_rq)) | |
1255 | return MAX_PRIO; | |
1256 | ||
1257 | curr = cfs_rq->curr; | |
1258 | if (!curr) | |
1259 | curr = __pick_next_entity(cfs_rq); | |
1260 | ||
1261 | p = task_of(curr); | |
1262 | ||
1263 | return p->prio; | |
1264 | } | |
1265 | #endif | |
1266 | ||
43010659 | 1267 | static unsigned long |
bf0f6f24 | 1268 | load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest, |
e1d1484f | 1269 | unsigned long max_load_move, |
a4ac01c3 PW |
1270 | struct sched_domain *sd, enum cpu_idle_type idle, |
1271 | int *all_pinned, int *this_best_prio) | |
bf0f6f24 IM |
1272 | { |
1273 | struct cfs_rq *busy_cfs_rq; | |
bf0f6f24 IM |
1274 | long rem_load_move = max_load_move; |
1275 | struct rq_iterator cfs_rq_iterator; | |
1276 | ||
1277 | cfs_rq_iterator.start = load_balance_start_fair; | |
1278 | cfs_rq_iterator.next = load_balance_next_fair; | |
1279 | ||
1280 | for_each_leaf_cfs_rq(busiest, busy_cfs_rq) { | |
a4ac01c3 | 1281 | #ifdef CONFIG_FAIR_GROUP_SCHED |
62fb1851 PZ |
1282 | struct cfs_rq *this_cfs_rq; |
1283 | long imbalance; | |
1284 | unsigned long maxload; | |
bf0f6f24 | 1285 | |
62fb1851 | 1286 | this_cfs_rq = cpu_cfs_rq(busy_cfs_rq, this_cpu); |
6b2d7700 | 1287 | |
62fb1851 PZ |
1288 | imbalance = busy_cfs_rq->load.weight - this_cfs_rq->load.weight; |
1289 | /* Don't pull if this_cfs_rq has more load than busy_cfs_rq */ | |
1290 | if (imbalance <= 0) | |
bf0f6f24 IM |
1291 | continue; |
1292 | ||
62fb1851 PZ |
1293 | /* Don't pull more than imbalance/2 */ |
1294 | imbalance /= 2; | |
1295 | maxload = min(rem_load_move, imbalance); | |
bf0f6f24 | 1296 | |
62fb1851 | 1297 | *this_best_prio = cfs_rq_best_prio(this_cfs_rq); |
a4ac01c3 | 1298 | #else |
e56f31aa | 1299 | # define maxload rem_load_move |
a4ac01c3 | 1300 | #endif |
e1d1484f PW |
1301 | /* |
1302 | * pass busy_cfs_rq argument into | |
bf0f6f24 IM |
1303 | * load_balance_[start|next]_fair iterators |
1304 | */ | |
1305 | cfs_rq_iterator.arg = busy_cfs_rq; | |
62fb1851 | 1306 | rem_load_move -= balance_tasks(this_rq, this_cpu, busiest, |
e1d1484f PW |
1307 | maxload, sd, idle, all_pinned, |
1308 | this_best_prio, | |
1309 | &cfs_rq_iterator); | |
bf0f6f24 | 1310 | |
e1d1484f | 1311 | if (rem_load_move <= 0) |
bf0f6f24 IM |
1312 | break; |
1313 | } | |
1314 | ||
43010659 | 1315 | return max_load_move - rem_load_move; |
bf0f6f24 IM |
1316 | } |
1317 | ||
e1d1484f PW |
1318 | static int |
1319 | move_one_task_fair(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
1320 | struct sched_domain *sd, enum cpu_idle_type idle) | |
1321 | { | |
1322 | struct cfs_rq *busy_cfs_rq; | |
1323 | struct rq_iterator cfs_rq_iterator; | |
1324 | ||
1325 | cfs_rq_iterator.start = load_balance_start_fair; | |
1326 | cfs_rq_iterator.next = load_balance_next_fair; | |
1327 | ||
1328 | for_each_leaf_cfs_rq(busiest, busy_cfs_rq) { | |
1329 | /* | |
1330 | * pass busy_cfs_rq argument into | |
1331 | * load_balance_[start|next]_fair iterators | |
1332 | */ | |
1333 | cfs_rq_iterator.arg = busy_cfs_rq; | |
1334 | if (iter_move_one_task(this_rq, this_cpu, busiest, sd, idle, | |
1335 | &cfs_rq_iterator)) | |
1336 | return 1; | |
1337 | } | |
1338 | ||
1339 | return 0; | |
1340 | } | |
681f3e68 | 1341 | #endif |
e1d1484f | 1342 | |
bf0f6f24 IM |
1343 | /* |
1344 | * scheduler tick hitting a task of our scheduling class: | |
1345 | */ | |
8f4d37ec | 1346 | static void task_tick_fair(struct rq *rq, struct task_struct *curr, int queued) |
bf0f6f24 IM |
1347 | { |
1348 | struct cfs_rq *cfs_rq; | |
1349 | struct sched_entity *se = &curr->se; | |
1350 | ||
1351 | for_each_sched_entity(se) { | |
1352 | cfs_rq = cfs_rq_of(se); | |
8f4d37ec | 1353 | entity_tick(cfs_rq, se, queued); |
bf0f6f24 IM |
1354 | } |
1355 | } | |
1356 | ||
8eb172d9 | 1357 | #define swap(a, b) do { typeof(a) tmp = (a); (a) = (b); (b) = tmp; } while (0) |
4d78e7b6 | 1358 | |
bf0f6f24 IM |
1359 | /* |
1360 | * Share the fairness runtime between parent and child, thus the | |
1361 | * total amount of pressure for CPU stays equal - new tasks | |
1362 | * get a chance to run but frequent forkers are not allowed to | |
1363 | * monopolize the CPU. Note: the parent runqueue is locked, | |
1364 | * the child is not running yet. | |
1365 | */ | |
ee0827d8 | 1366 | static void task_new_fair(struct rq *rq, struct task_struct *p) |
bf0f6f24 IM |
1367 | { |
1368 | struct cfs_rq *cfs_rq = task_cfs_rq(p); | |
429d43bc | 1369 | struct sched_entity *se = &p->se, *curr = cfs_rq->curr; |
00bf7bfc | 1370 | int this_cpu = smp_processor_id(); |
bf0f6f24 IM |
1371 | |
1372 | sched_info_queued(p); | |
1373 | ||
7109c442 | 1374 | update_curr(cfs_rq); |
aeb73b04 | 1375 | place_entity(cfs_rq, se, 1); |
4d78e7b6 | 1376 | |
3c90e6e9 | 1377 | /* 'curr' will be NULL if the child belongs to a different group */ |
00bf7bfc | 1378 | if (sysctl_sched_child_runs_first && this_cpu == task_cpu(p) && |
3c90e6e9 | 1379 | curr && curr->vruntime < se->vruntime) { |
87fefa38 | 1380 | /* |
edcb60a3 IM |
1381 | * Upon rescheduling, sched_class::put_prev_task() will place |
1382 | * 'current' within the tree based on its new key value. | |
1383 | */ | |
4d78e7b6 | 1384 | swap(curr->vruntime, se->vruntime); |
4d78e7b6 | 1385 | } |
bf0f6f24 | 1386 | |
b9dca1e0 | 1387 | enqueue_task_fair(rq, p, 0); |
bb61c210 | 1388 | resched_task(rq->curr); |
bf0f6f24 IM |
1389 | } |
1390 | ||
cb469845 SR |
1391 | /* |
1392 | * Priority of the task has changed. Check to see if we preempt | |
1393 | * the current task. | |
1394 | */ | |
1395 | static void prio_changed_fair(struct rq *rq, struct task_struct *p, | |
1396 | int oldprio, int running) | |
1397 | { | |
1398 | /* | |
1399 | * Reschedule if we are currently running on this runqueue and | |
1400 | * our priority decreased, or if we are not currently running on | |
1401 | * this runqueue and our priority is higher than the current's | |
1402 | */ | |
1403 | if (running) { | |
1404 | if (p->prio > oldprio) | |
1405 | resched_task(rq->curr); | |
1406 | } else | |
1407 | check_preempt_curr(rq, p); | |
1408 | } | |
1409 | ||
1410 | /* | |
1411 | * We switched to the sched_fair class. | |
1412 | */ | |
1413 | static void switched_to_fair(struct rq *rq, struct task_struct *p, | |
1414 | int running) | |
1415 | { | |
1416 | /* | |
1417 | * We were most likely switched from sched_rt, so | |
1418 | * kick off the schedule if running, otherwise just see | |
1419 | * if we can still preempt the current task. | |
1420 | */ | |
1421 | if (running) | |
1422 | resched_task(rq->curr); | |
1423 | else | |
1424 | check_preempt_curr(rq, p); | |
1425 | } | |
1426 | ||
83b699ed SV |
1427 | /* Account for a task changing its policy or group. |
1428 | * | |
1429 | * This routine is mostly called to set cfs_rq->curr field when a task | |
1430 | * migrates between groups/classes. | |
1431 | */ | |
1432 | static void set_curr_task_fair(struct rq *rq) | |
1433 | { | |
1434 | struct sched_entity *se = &rq->curr->se; | |
1435 | ||
1436 | for_each_sched_entity(se) | |
1437 | set_next_entity(cfs_rq_of(se), se); | |
1438 | } | |
1439 | ||
810b3817 PZ |
1440 | #ifdef CONFIG_FAIR_GROUP_SCHED |
1441 | static void moved_group_fair(struct task_struct *p) | |
1442 | { | |
1443 | struct cfs_rq *cfs_rq = task_cfs_rq(p); | |
1444 | ||
1445 | update_curr(cfs_rq); | |
1446 | place_entity(cfs_rq, &p->se, 1); | |
1447 | } | |
1448 | #endif | |
1449 | ||
bf0f6f24 IM |
1450 | /* |
1451 | * All the scheduling class methods: | |
1452 | */ | |
5522d5d5 IM |
1453 | static const struct sched_class fair_sched_class = { |
1454 | .next = &idle_sched_class, | |
bf0f6f24 IM |
1455 | .enqueue_task = enqueue_task_fair, |
1456 | .dequeue_task = dequeue_task_fair, | |
1457 | .yield_task = yield_task_fair, | |
e7693a36 GH |
1458 | #ifdef CONFIG_SMP |
1459 | .select_task_rq = select_task_rq_fair, | |
1460 | #endif /* CONFIG_SMP */ | |
bf0f6f24 | 1461 | |
2e09bf55 | 1462 | .check_preempt_curr = check_preempt_wakeup, |
bf0f6f24 IM |
1463 | |
1464 | .pick_next_task = pick_next_task_fair, | |
1465 | .put_prev_task = put_prev_task_fair, | |
1466 | ||
681f3e68 | 1467 | #ifdef CONFIG_SMP |
bf0f6f24 | 1468 | .load_balance = load_balance_fair, |
e1d1484f | 1469 | .move_one_task = move_one_task_fair, |
681f3e68 | 1470 | #endif |
bf0f6f24 | 1471 | |
83b699ed | 1472 | .set_curr_task = set_curr_task_fair, |
bf0f6f24 IM |
1473 | .task_tick = task_tick_fair, |
1474 | .task_new = task_new_fair, | |
cb469845 SR |
1475 | |
1476 | .prio_changed = prio_changed_fair, | |
1477 | .switched_to = switched_to_fair, | |
810b3817 PZ |
1478 | |
1479 | #ifdef CONFIG_FAIR_GROUP_SCHED | |
1480 | .moved_group = moved_group_fair, | |
1481 | #endif | |
bf0f6f24 IM |
1482 | }; |
1483 | ||
1484 | #ifdef CONFIG_SCHED_DEBUG | |
5cef9eca | 1485 | static void print_cfs_stats(struct seq_file *m, int cpu) |
bf0f6f24 | 1486 | { |
bf0f6f24 IM |
1487 | struct cfs_rq *cfs_rq; |
1488 | ||
75c28ace SV |
1489 | #ifdef CONFIG_FAIR_GROUP_SCHED |
1490 | print_cfs_rq(m, cpu, &cpu_rq(cpu)->cfs); | |
1491 | #endif | |
5973e5b9 | 1492 | rcu_read_lock(); |
c3b64f1e | 1493 | for_each_leaf_cfs_rq(cpu_rq(cpu), cfs_rq) |
5cef9eca | 1494 | print_cfs_rq(m, cpu, cfs_rq); |
5973e5b9 | 1495 | rcu_read_unlock(); |
bf0f6f24 IM |
1496 | } |
1497 | #endif |