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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_BATCH wake-up granularity. | |
722aab0c | 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 | */ | |
19978ca6 | 72 | unsigned int sysctl_sched_batch_wakeup_granularity = 10000000UL; |
bf0f6f24 IM |
73 | |
74 | /* | |
75 | * SCHED_OTHER wake-up granularity. | |
74e3cd7f | 76 | * (default: 5 msec * (1 + ilog(ncpus)), units: nanoseconds) |
bf0f6f24 IM |
77 | * |
78 | * This option delays the preemption effects of decoupled workloads | |
79 | * and reduces their over-scheduling. Synchronous workloads will still | |
80 | * have immediate wakeup/sleep latencies. | |
81 | */ | |
74e3cd7f | 82 | unsigned int sysctl_sched_wakeup_granularity = 5000000UL; |
bf0f6f24 | 83 | |
da84d961 IM |
84 | const_debug unsigned int sysctl_sched_migration_cost = 500000UL; |
85 | ||
bf0f6f24 IM |
86 | /************************************************************** |
87 | * CFS operations on generic schedulable entities: | |
88 | */ | |
89 | ||
62160e3f | 90 | #ifdef CONFIG_FAIR_GROUP_SCHED |
bf0f6f24 | 91 | |
62160e3f | 92 | /* cpu runqueue to which this cfs_rq is attached */ |
bf0f6f24 IM |
93 | static inline struct rq *rq_of(struct cfs_rq *cfs_rq) |
94 | { | |
62160e3f | 95 | return cfs_rq->rq; |
bf0f6f24 IM |
96 | } |
97 | ||
62160e3f IM |
98 | /* An entity is a task if it doesn't "own" a runqueue */ |
99 | #define entity_is_task(se) (!se->my_q) | |
bf0f6f24 | 100 | |
62160e3f | 101 | #else /* CONFIG_FAIR_GROUP_SCHED */ |
bf0f6f24 | 102 | |
62160e3f IM |
103 | static inline struct rq *rq_of(struct cfs_rq *cfs_rq) |
104 | { | |
105 | return container_of(cfs_rq, struct rq, cfs); | |
bf0f6f24 IM |
106 | } |
107 | ||
108 | #define entity_is_task(se) 1 | |
109 | ||
bf0f6f24 IM |
110 | #endif /* CONFIG_FAIR_GROUP_SCHED */ |
111 | ||
112 | static inline struct task_struct *task_of(struct sched_entity *se) | |
113 | { | |
114 | return container_of(se, struct task_struct, se); | |
115 | } | |
116 | ||
117 | ||
118 | /************************************************************** | |
119 | * Scheduling class tree data structure manipulation methods: | |
120 | */ | |
121 | ||
0702e3eb | 122 | static inline u64 max_vruntime(u64 min_vruntime, u64 vruntime) |
02e0431a | 123 | { |
368059a9 PZ |
124 | s64 delta = (s64)(vruntime - min_vruntime); |
125 | if (delta > 0) | |
02e0431a PZ |
126 | min_vruntime = vruntime; |
127 | ||
128 | return min_vruntime; | |
129 | } | |
130 | ||
0702e3eb | 131 | static inline u64 min_vruntime(u64 min_vruntime, u64 vruntime) |
b0ffd246 PZ |
132 | { |
133 | s64 delta = (s64)(vruntime - min_vruntime); | |
134 | if (delta < 0) | |
135 | min_vruntime = vruntime; | |
136 | ||
137 | return min_vruntime; | |
138 | } | |
139 | ||
0702e3eb | 140 | static inline s64 entity_key(struct cfs_rq *cfs_rq, struct sched_entity *se) |
9014623c | 141 | { |
30cfdcfc | 142 | return se->vruntime - cfs_rq->min_vruntime; |
9014623c PZ |
143 | } |
144 | ||
bf0f6f24 IM |
145 | /* |
146 | * Enqueue an entity into the rb-tree: | |
147 | */ | |
0702e3eb | 148 | static void __enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 IM |
149 | { |
150 | struct rb_node **link = &cfs_rq->tasks_timeline.rb_node; | |
151 | struct rb_node *parent = NULL; | |
152 | struct sched_entity *entry; | |
9014623c | 153 | s64 key = entity_key(cfs_rq, se); |
bf0f6f24 IM |
154 | int leftmost = 1; |
155 | ||
156 | /* | |
157 | * Find the right place in the rbtree: | |
158 | */ | |
159 | while (*link) { | |
160 | parent = *link; | |
161 | entry = rb_entry(parent, struct sched_entity, run_node); | |
162 | /* | |
163 | * We dont care about collisions. Nodes with | |
164 | * the same key stay together. | |
165 | */ | |
9014623c | 166 | if (key < entity_key(cfs_rq, entry)) { |
bf0f6f24 IM |
167 | link = &parent->rb_left; |
168 | } else { | |
169 | link = &parent->rb_right; | |
170 | leftmost = 0; | |
171 | } | |
172 | } | |
173 | ||
174 | /* | |
175 | * Maintain a cache of leftmost tree entries (it is frequently | |
176 | * used): | |
177 | */ | |
3fe69747 | 178 | if (leftmost) { |
57cb499d | 179 | cfs_rq->rb_leftmost = &se->run_node; |
3fe69747 PZ |
180 | /* |
181 | * maintain cfs_rq->min_vruntime to be a monotonic increasing | |
182 | * value tracking the leftmost vruntime in the tree. | |
183 | */ | |
184 | cfs_rq->min_vruntime = | |
185 | max_vruntime(cfs_rq->min_vruntime, se->vruntime); | |
186 | } | |
bf0f6f24 IM |
187 | |
188 | rb_link_node(&se->run_node, parent, link); | |
189 | rb_insert_color(&se->run_node, &cfs_rq->tasks_timeline); | |
bf0f6f24 IM |
190 | } |
191 | ||
0702e3eb | 192 | static void __dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 193 | { |
3fe69747 PZ |
194 | if (cfs_rq->rb_leftmost == &se->run_node) { |
195 | struct rb_node *next_node; | |
196 | struct sched_entity *next; | |
197 | ||
198 | next_node = rb_next(&se->run_node); | |
199 | cfs_rq->rb_leftmost = next_node; | |
200 | ||
201 | if (next_node) { | |
202 | next = rb_entry(next_node, | |
203 | struct sched_entity, run_node); | |
204 | cfs_rq->min_vruntime = | |
205 | max_vruntime(cfs_rq->min_vruntime, | |
206 | next->vruntime); | |
207 | } | |
208 | } | |
e9acbff6 | 209 | |
aa2ac252 PZ |
210 | if (cfs_rq->next == se) |
211 | cfs_rq->next = NULL; | |
212 | ||
bf0f6f24 | 213 | rb_erase(&se->run_node, &cfs_rq->tasks_timeline); |
bf0f6f24 IM |
214 | } |
215 | ||
216 | static inline struct rb_node *first_fair(struct cfs_rq *cfs_rq) | |
217 | { | |
218 | return cfs_rq->rb_leftmost; | |
219 | } | |
220 | ||
221 | static struct sched_entity *__pick_next_entity(struct cfs_rq *cfs_rq) | |
222 | { | |
223 | return rb_entry(first_fair(cfs_rq), struct sched_entity, run_node); | |
224 | } | |
225 | ||
aeb73b04 PZ |
226 | static inline struct sched_entity *__pick_last_entity(struct cfs_rq *cfs_rq) |
227 | { | |
7eee3e67 | 228 | struct rb_node *last = rb_last(&cfs_rq->tasks_timeline); |
aeb73b04 | 229 | |
70eee74b BS |
230 | if (!last) |
231 | return NULL; | |
7eee3e67 IM |
232 | |
233 | return rb_entry(last, struct sched_entity, run_node); | |
aeb73b04 PZ |
234 | } |
235 | ||
bf0f6f24 IM |
236 | /************************************************************** |
237 | * Scheduling class statistics methods: | |
238 | */ | |
239 | ||
b2be5e96 PZ |
240 | #ifdef CONFIG_SCHED_DEBUG |
241 | int sched_nr_latency_handler(struct ctl_table *table, int write, | |
242 | struct file *filp, void __user *buffer, size_t *lenp, | |
243 | loff_t *ppos) | |
244 | { | |
245 | int ret = proc_dointvec_minmax(table, write, filp, buffer, lenp, ppos); | |
246 | ||
247 | if (ret || !write) | |
248 | return ret; | |
249 | ||
250 | sched_nr_latency = DIV_ROUND_UP(sysctl_sched_latency, | |
251 | sysctl_sched_min_granularity); | |
252 | ||
253 | return 0; | |
254 | } | |
255 | #endif | |
647e7cac IM |
256 | |
257 | /* | |
258 | * The idea is to set a period in which each task runs once. | |
259 | * | |
260 | * When there are too many tasks (sysctl_sched_nr_latency) we have to stretch | |
261 | * this period because otherwise the slices get too small. | |
262 | * | |
263 | * p = (nr <= nl) ? l : l*nr/nl | |
264 | */ | |
4d78e7b6 PZ |
265 | static u64 __sched_period(unsigned long nr_running) |
266 | { | |
267 | u64 period = sysctl_sched_latency; | |
b2be5e96 | 268 | unsigned long nr_latency = sched_nr_latency; |
4d78e7b6 PZ |
269 | |
270 | if (unlikely(nr_running > nr_latency)) { | |
4bf0b771 | 271 | period = sysctl_sched_min_granularity; |
4d78e7b6 | 272 | period *= nr_running; |
4d78e7b6 PZ |
273 | } |
274 | ||
275 | return period; | |
276 | } | |
277 | ||
647e7cac IM |
278 | /* |
279 | * We calculate the wall-time slice from the period by taking a part | |
280 | * proportional to the weight. | |
281 | * | |
282 | * s = p*w/rw | |
283 | */ | |
6d0f0ebd | 284 | static u64 sched_slice(struct cfs_rq *cfs_rq, struct sched_entity *se) |
21805085 | 285 | { |
6a6029b8 IM |
286 | return calc_delta_mine(__sched_period(cfs_rq->nr_running), |
287 | se->load.weight, &cfs_rq->load); | |
bf0f6f24 IM |
288 | } |
289 | ||
647e7cac IM |
290 | /* |
291 | * We calculate the vruntime slice. | |
292 | * | |
293 | * vs = s/w = p/rw | |
294 | */ | |
295 | static u64 __sched_vslice(unsigned long rq_weight, unsigned long nr_running) | |
67e9fb2a | 296 | { |
647e7cac | 297 | u64 vslice = __sched_period(nr_running); |
67e9fb2a | 298 | |
10b77724 | 299 | vslice *= NICE_0_LOAD; |
647e7cac | 300 | do_div(vslice, rq_weight); |
67e9fb2a | 301 | |
647e7cac IM |
302 | return vslice; |
303 | } | |
5f6d858e | 304 | |
647e7cac IM |
305 | static u64 sched_vslice_add(struct cfs_rq *cfs_rq, struct sched_entity *se) |
306 | { | |
307 | return __sched_vslice(cfs_rq->load.weight + se->load.weight, | |
308 | cfs_rq->nr_running + 1); | |
67e9fb2a PZ |
309 | } |
310 | ||
bf0f6f24 IM |
311 | /* |
312 | * Update the current task's runtime statistics. Skip current tasks that | |
313 | * are not in our scheduling class. | |
314 | */ | |
315 | static inline void | |
8ebc91d9 IM |
316 | __update_curr(struct cfs_rq *cfs_rq, struct sched_entity *curr, |
317 | unsigned long delta_exec) | |
bf0f6f24 | 318 | { |
bbdba7c0 | 319 | unsigned long delta_exec_weighted; |
bf0f6f24 | 320 | |
8179ca23 | 321 | schedstat_set(curr->exec_max, max((u64)delta_exec, curr->exec_max)); |
bf0f6f24 IM |
322 | |
323 | curr->sum_exec_runtime += delta_exec; | |
7a62eabc | 324 | schedstat_add(cfs_rq, exec_clock, delta_exec); |
e9acbff6 IM |
325 | delta_exec_weighted = delta_exec; |
326 | if (unlikely(curr->load.weight != NICE_0_LOAD)) { | |
327 | delta_exec_weighted = calc_delta_fair(delta_exec_weighted, | |
328 | &curr->load); | |
329 | } | |
330 | curr->vruntime += delta_exec_weighted; | |
bf0f6f24 IM |
331 | } |
332 | ||
b7cc0896 | 333 | static void update_curr(struct cfs_rq *cfs_rq) |
bf0f6f24 | 334 | { |
429d43bc | 335 | struct sched_entity *curr = cfs_rq->curr; |
8ebc91d9 | 336 | u64 now = rq_of(cfs_rq)->clock; |
bf0f6f24 IM |
337 | unsigned long delta_exec; |
338 | ||
339 | if (unlikely(!curr)) | |
340 | return; | |
341 | ||
342 | /* | |
343 | * Get the amount of time the current task was running | |
344 | * since the last time we changed load (this cannot | |
345 | * overflow on 32 bits): | |
346 | */ | |
8ebc91d9 | 347 | delta_exec = (unsigned long)(now - curr->exec_start); |
bf0f6f24 | 348 | |
8ebc91d9 IM |
349 | __update_curr(cfs_rq, curr, delta_exec); |
350 | curr->exec_start = now; | |
d842de87 SV |
351 | |
352 | if (entity_is_task(curr)) { | |
353 | struct task_struct *curtask = task_of(curr); | |
354 | ||
355 | cpuacct_charge(curtask, delta_exec); | |
356 | } | |
bf0f6f24 IM |
357 | } |
358 | ||
359 | static inline void | |
5870db5b | 360 | update_stats_wait_start(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 361 | { |
d281918d | 362 | schedstat_set(se->wait_start, rq_of(cfs_rq)->clock); |
bf0f6f24 IM |
363 | } |
364 | ||
bf0f6f24 IM |
365 | /* |
366 | * Task is being enqueued - update stats: | |
367 | */ | |
d2417e5a | 368 | static void update_stats_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 369 | { |
bf0f6f24 IM |
370 | /* |
371 | * Are we enqueueing a waiting task? (for current tasks | |
372 | * a dequeue/enqueue event is a NOP) | |
373 | */ | |
429d43bc | 374 | if (se != cfs_rq->curr) |
5870db5b | 375 | update_stats_wait_start(cfs_rq, se); |
bf0f6f24 IM |
376 | } |
377 | ||
bf0f6f24 | 378 | static void |
9ef0a961 | 379 | update_stats_wait_end(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 380 | { |
bbdba7c0 IM |
381 | schedstat_set(se->wait_max, max(se->wait_max, |
382 | rq_of(cfs_rq)->clock - se->wait_start)); | |
6d082592 AV |
383 | schedstat_set(se->wait_count, se->wait_count + 1); |
384 | schedstat_set(se->wait_sum, se->wait_sum + | |
385 | rq_of(cfs_rq)->clock - se->wait_start); | |
6cfb0d5d | 386 | schedstat_set(se->wait_start, 0); |
bf0f6f24 IM |
387 | } |
388 | ||
389 | static inline void | |
19b6a2e3 | 390 | update_stats_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 391 | { |
bf0f6f24 IM |
392 | /* |
393 | * Mark the end of the wait period if dequeueing a | |
394 | * waiting task: | |
395 | */ | |
429d43bc | 396 | if (se != cfs_rq->curr) |
9ef0a961 | 397 | update_stats_wait_end(cfs_rq, se); |
bf0f6f24 IM |
398 | } |
399 | ||
400 | /* | |
401 | * We are picking a new current task - update its stats: | |
402 | */ | |
403 | static inline void | |
79303e9e | 404 | update_stats_curr_start(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 IM |
405 | { |
406 | /* | |
407 | * We are starting a new run period: | |
408 | */ | |
d281918d | 409 | se->exec_start = rq_of(cfs_rq)->clock; |
bf0f6f24 IM |
410 | } |
411 | ||
bf0f6f24 IM |
412 | /************************************************** |
413 | * Scheduling class queueing methods: | |
414 | */ | |
415 | ||
30cfdcfc DA |
416 | static void |
417 | account_entity_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se) | |
418 | { | |
419 | update_load_add(&cfs_rq->load, se->load.weight); | |
420 | cfs_rq->nr_running++; | |
421 | se->on_rq = 1; | |
422 | } | |
423 | ||
424 | static void | |
425 | account_entity_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se) | |
426 | { | |
427 | update_load_sub(&cfs_rq->load, se->load.weight); | |
428 | cfs_rq->nr_running--; | |
429 | se->on_rq = 0; | |
430 | } | |
431 | ||
2396af69 | 432 | static void enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 433 | { |
bf0f6f24 IM |
434 | #ifdef CONFIG_SCHEDSTATS |
435 | if (se->sleep_start) { | |
d281918d | 436 | u64 delta = rq_of(cfs_rq)->clock - se->sleep_start; |
9745512c | 437 | struct task_struct *tsk = task_of(se); |
bf0f6f24 IM |
438 | |
439 | if ((s64)delta < 0) | |
440 | delta = 0; | |
441 | ||
442 | if (unlikely(delta > se->sleep_max)) | |
443 | se->sleep_max = delta; | |
444 | ||
445 | se->sleep_start = 0; | |
446 | se->sum_sleep_runtime += delta; | |
9745512c AV |
447 | |
448 | account_scheduler_latency(tsk, delta >> 10, 1); | |
bf0f6f24 IM |
449 | } |
450 | if (se->block_start) { | |
d281918d | 451 | u64 delta = rq_of(cfs_rq)->clock - se->block_start; |
9745512c | 452 | struct task_struct *tsk = task_of(se); |
bf0f6f24 IM |
453 | |
454 | if ((s64)delta < 0) | |
455 | delta = 0; | |
456 | ||
457 | if (unlikely(delta > se->block_max)) | |
458 | se->block_max = delta; | |
459 | ||
460 | se->block_start = 0; | |
461 | se->sum_sleep_runtime += delta; | |
30084fbd IM |
462 | |
463 | /* | |
464 | * Blocking time is in units of nanosecs, so shift by 20 to | |
465 | * get a milliseconds-range estimation of the amount of | |
466 | * time that the task spent sleeping: | |
467 | */ | |
468 | if (unlikely(prof_on == SLEEP_PROFILING)) { | |
e22f5bbf | 469 | |
30084fbd IM |
470 | profile_hits(SLEEP_PROFILING, (void *)get_wchan(tsk), |
471 | delta >> 20); | |
472 | } | |
9745512c | 473 | account_scheduler_latency(tsk, delta >> 10, 0); |
bf0f6f24 IM |
474 | } |
475 | #endif | |
476 | } | |
477 | ||
ddc97297 PZ |
478 | static void check_spread(struct cfs_rq *cfs_rq, struct sched_entity *se) |
479 | { | |
480 | #ifdef CONFIG_SCHED_DEBUG | |
481 | s64 d = se->vruntime - cfs_rq->min_vruntime; | |
482 | ||
483 | if (d < 0) | |
484 | d = -d; | |
485 | ||
486 | if (d > 3*sysctl_sched_latency) | |
487 | schedstat_inc(cfs_rq, nr_spread_over); | |
488 | #endif | |
489 | } | |
490 | ||
aeb73b04 PZ |
491 | static void |
492 | place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial) | |
493 | { | |
67e9fb2a | 494 | u64 vruntime; |
aeb73b04 | 495 | |
3fe69747 PZ |
496 | if (first_fair(cfs_rq)) { |
497 | vruntime = min_vruntime(cfs_rq->min_vruntime, | |
498 | __pick_next_entity(cfs_rq)->vruntime); | |
499 | } else | |
500 | vruntime = cfs_rq->min_vruntime; | |
94dfb5e7 | 501 | |
2cb8600e PZ |
502 | /* |
503 | * The 'current' period is already promised to the current tasks, | |
504 | * however the extra weight of the new task will slow them down a | |
505 | * little, place the new task so that it fits in the slot that | |
506 | * stays open at the end. | |
507 | */ | |
94dfb5e7 | 508 | if (initial && sched_feat(START_DEBIT)) |
647e7cac | 509 | vruntime += sched_vslice_add(cfs_rq, se); |
aeb73b04 | 510 | |
8465e792 | 511 | if (!initial) { |
2cb8600e | 512 | /* sleeps upto a single latency don't count. */ |
e22ecef1 IM |
513 | if (sched_feat(NEW_FAIR_SLEEPERS)) { |
514 | vruntime -= calc_delta_fair(sysctl_sched_latency, | |
515 | &cfs_rq->load); | |
516 | } | |
94359f05 | 517 | |
2cb8600e PZ |
518 | /* ensure we never gain time by being placed backwards. */ |
519 | vruntime = max_vruntime(se->vruntime, vruntime); | |
aeb73b04 PZ |
520 | } |
521 | ||
67e9fb2a | 522 | se->vruntime = vruntime; |
aeb73b04 PZ |
523 | } |
524 | ||
bf0f6f24 | 525 | static void |
83b699ed | 526 | enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int wakeup) |
bf0f6f24 IM |
527 | { |
528 | /* | |
a2a2d680 | 529 | * Update run-time statistics of the 'current'. |
bf0f6f24 | 530 | */ |
b7cc0896 | 531 | update_curr(cfs_rq); |
bf0f6f24 | 532 | |
e9acbff6 | 533 | if (wakeup) { |
aeb73b04 | 534 | place_entity(cfs_rq, se, 0); |
2396af69 | 535 | enqueue_sleeper(cfs_rq, se); |
e9acbff6 | 536 | } |
bf0f6f24 | 537 | |
d2417e5a | 538 | update_stats_enqueue(cfs_rq, se); |
ddc97297 | 539 | check_spread(cfs_rq, se); |
83b699ed SV |
540 | if (se != cfs_rq->curr) |
541 | __enqueue_entity(cfs_rq, se); | |
30cfdcfc | 542 | account_entity_enqueue(cfs_rq, se); |
bf0f6f24 IM |
543 | } |
544 | ||
4ae7d5ce IM |
545 | static void update_avg(u64 *avg, u64 sample) |
546 | { | |
547 | s64 diff = sample - *avg; | |
548 | *avg += diff >> 3; | |
549 | } | |
550 | ||
551 | static void update_avg_stats(struct cfs_rq *cfs_rq, struct sched_entity *se) | |
552 | { | |
553 | if (!se->last_wakeup) | |
554 | return; | |
555 | ||
556 | update_avg(&se->avg_overlap, se->sum_exec_runtime - se->last_wakeup); | |
557 | se->last_wakeup = 0; | |
558 | } | |
559 | ||
bf0f6f24 | 560 | static void |
525c2716 | 561 | dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int sleep) |
bf0f6f24 | 562 | { |
a2a2d680 DA |
563 | /* |
564 | * Update run-time statistics of the 'current'. | |
565 | */ | |
566 | update_curr(cfs_rq); | |
567 | ||
19b6a2e3 | 568 | update_stats_dequeue(cfs_rq, se); |
db36cc7d | 569 | if (sleep) { |
4ae7d5ce | 570 | update_avg_stats(cfs_rq, se); |
67e9fb2a | 571 | #ifdef CONFIG_SCHEDSTATS |
bf0f6f24 IM |
572 | if (entity_is_task(se)) { |
573 | struct task_struct *tsk = task_of(se); | |
574 | ||
575 | if (tsk->state & TASK_INTERRUPTIBLE) | |
d281918d | 576 | se->sleep_start = rq_of(cfs_rq)->clock; |
bf0f6f24 | 577 | if (tsk->state & TASK_UNINTERRUPTIBLE) |
d281918d | 578 | se->block_start = rq_of(cfs_rq)->clock; |
bf0f6f24 | 579 | } |
db36cc7d | 580 | #endif |
67e9fb2a PZ |
581 | } |
582 | ||
83b699ed | 583 | if (se != cfs_rq->curr) |
30cfdcfc DA |
584 | __dequeue_entity(cfs_rq, se); |
585 | account_entity_dequeue(cfs_rq, se); | |
bf0f6f24 IM |
586 | } |
587 | ||
588 | /* | |
589 | * Preempt the current task with a newly woken task if needed: | |
590 | */ | |
7c92e54f | 591 | static void |
2e09bf55 | 592 | check_preempt_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr) |
bf0f6f24 | 593 | { |
11697830 PZ |
594 | unsigned long ideal_runtime, delta_exec; |
595 | ||
6d0f0ebd | 596 | ideal_runtime = sched_slice(cfs_rq, curr); |
11697830 | 597 | delta_exec = curr->sum_exec_runtime - curr->prev_sum_exec_runtime; |
3e3e13f3 | 598 | if (delta_exec > ideal_runtime) |
bf0f6f24 IM |
599 | resched_task(rq_of(cfs_rq)->curr); |
600 | } | |
601 | ||
83b699ed | 602 | static void |
8494f412 | 603 | set_next_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 604 | { |
83b699ed SV |
605 | /* 'current' is not kept within the tree. */ |
606 | if (se->on_rq) { | |
607 | /* | |
608 | * Any task has to be enqueued before it get to execute on | |
609 | * a CPU. So account for the time it spent waiting on the | |
610 | * runqueue. | |
611 | */ | |
612 | update_stats_wait_end(cfs_rq, se); | |
613 | __dequeue_entity(cfs_rq, se); | |
614 | } | |
615 | ||
79303e9e | 616 | update_stats_curr_start(cfs_rq, se); |
429d43bc | 617 | cfs_rq->curr = se; |
eba1ed4b IM |
618 | #ifdef CONFIG_SCHEDSTATS |
619 | /* | |
620 | * Track our maximum slice length, if the CPU's load is at | |
621 | * least twice that of our own weight (i.e. dont track it | |
622 | * when there are only lesser-weight tasks around): | |
623 | */ | |
495eca49 | 624 | if (rq_of(cfs_rq)->load.weight >= 2*se->load.weight) { |
eba1ed4b IM |
625 | se->slice_max = max(se->slice_max, |
626 | se->sum_exec_runtime - se->prev_sum_exec_runtime); | |
627 | } | |
628 | #endif | |
4a55b450 | 629 | se->prev_sum_exec_runtime = se->sum_exec_runtime; |
bf0f6f24 IM |
630 | } |
631 | ||
aa2ac252 PZ |
632 | static struct sched_entity * |
633 | pick_next(struct cfs_rq *cfs_rq, struct sched_entity *se) | |
634 | { | |
635 | s64 diff, gran; | |
636 | ||
637 | if (!cfs_rq->next) | |
638 | return se; | |
639 | ||
640 | diff = cfs_rq->next->vruntime - se->vruntime; | |
641 | if (diff < 0) | |
642 | return se; | |
643 | ||
644 | gran = calc_delta_fair(sysctl_sched_wakeup_granularity, &cfs_rq->load); | |
645 | if (diff > gran) | |
646 | return se; | |
647 | ||
648 | return cfs_rq->next; | |
649 | } | |
650 | ||
9948f4b2 | 651 | static struct sched_entity *pick_next_entity(struct cfs_rq *cfs_rq) |
bf0f6f24 | 652 | { |
08ec3df5 | 653 | struct sched_entity *se = NULL; |
bf0f6f24 | 654 | |
08ec3df5 DA |
655 | if (first_fair(cfs_rq)) { |
656 | se = __pick_next_entity(cfs_rq); | |
aa2ac252 | 657 | se = pick_next(cfs_rq, se); |
08ec3df5 DA |
658 | set_next_entity(cfs_rq, se); |
659 | } | |
bf0f6f24 IM |
660 | |
661 | return se; | |
662 | } | |
663 | ||
ab6cde26 | 664 | static void put_prev_entity(struct cfs_rq *cfs_rq, struct sched_entity *prev) |
bf0f6f24 IM |
665 | { |
666 | /* | |
667 | * If still on the runqueue then deactivate_task() | |
668 | * was not called and update_curr() has to be done: | |
669 | */ | |
670 | if (prev->on_rq) | |
b7cc0896 | 671 | update_curr(cfs_rq); |
bf0f6f24 | 672 | |
ddc97297 | 673 | check_spread(cfs_rq, prev); |
30cfdcfc | 674 | if (prev->on_rq) { |
5870db5b | 675 | update_stats_wait_start(cfs_rq, prev); |
30cfdcfc DA |
676 | /* Put 'current' back into the tree. */ |
677 | __enqueue_entity(cfs_rq, prev); | |
678 | } | |
429d43bc | 679 | cfs_rq->curr = NULL; |
bf0f6f24 IM |
680 | } |
681 | ||
8f4d37ec PZ |
682 | static void |
683 | entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr, int queued) | |
bf0f6f24 | 684 | { |
bf0f6f24 | 685 | /* |
30cfdcfc | 686 | * Update run-time statistics of the 'current'. |
bf0f6f24 | 687 | */ |
30cfdcfc | 688 | update_curr(cfs_rq); |
bf0f6f24 | 689 | |
8f4d37ec PZ |
690 | #ifdef CONFIG_SCHED_HRTICK |
691 | /* | |
692 | * queued ticks are scheduled to match the slice, so don't bother | |
693 | * validating it and just reschedule. | |
694 | */ | |
695 | if (queued) | |
696 | return resched_task(rq_of(cfs_rq)->curr); | |
697 | /* | |
698 | * don't let the period tick interfere with the hrtick preemption | |
699 | */ | |
700 | if (!sched_feat(DOUBLE_TICK) && | |
701 | hrtimer_active(&rq_of(cfs_rq)->hrtick_timer)) | |
702 | return; | |
703 | #endif | |
704 | ||
ce6c1311 | 705 | if (cfs_rq->nr_running > 1 || !sched_feat(WAKEUP_PREEMPT)) |
2e09bf55 | 706 | check_preempt_tick(cfs_rq, curr); |
bf0f6f24 IM |
707 | } |
708 | ||
709 | /************************************************** | |
710 | * CFS operations on tasks: | |
711 | */ | |
712 | ||
713 | #ifdef CONFIG_FAIR_GROUP_SCHED | |
714 | ||
715 | /* Walk up scheduling entities hierarchy */ | |
716 | #define for_each_sched_entity(se) \ | |
717 | for (; se; se = se->parent) | |
718 | ||
719 | static inline struct cfs_rq *task_cfs_rq(struct task_struct *p) | |
720 | { | |
721 | return p->se.cfs_rq; | |
722 | } | |
723 | ||
724 | /* runqueue on which this entity is (to be) queued */ | |
725 | static inline struct cfs_rq *cfs_rq_of(struct sched_entity *se) | |
726 | { | |
727 | return se->cfs_rq; | |
728 | } | |
729 | ||
730 | /* runqueue "owned" by this group */ | |
731 | static inline struct cfs_rq *group_cfs_rq(struct sched_entity *grp) | |
732 | { | |
733 | return grp->my_q; | |
734 | } | |
735 | ||
736 | /* Given a group's cfs_rq on one cpu, return its corresponding cfs_rq on | |
737 | * another cpu ('this_cpu') | |
738 | */ | |
739 | static inline struct cfs_rq *cpu_cfs_rq(struct cfs_rq *cfs_rq, int this_cpu) | |
740 | { | |
29f59db3 | 741 | return cfs_rq->tg->cfs_rq[this_cpu]; |
bf0f6f24 IM |
742 | } |
743 | ||
744 | /* Iterate thr' all leaf cfs_rq's on a runqueue */ | |
745 | #define for_each_leaf_cfs_rq(rq, cfs_rq) \ | |
ec2c507f | 746 | list_for_each_entry_rcu(cfs_rq, &rq->leaf_cfs_rq_list, leaf_cfs_rq_list) |
bf0f6f24 | 747 | |
fad095a7 SV |
748 | /* Do the two (enqueued) entities belong to the same group ? */ |
749 | static inline int | |
750 | is_same_group(struct sched_entity *se, struct sched_entity *pse) | |
bf0f6f24 | 751 | { |
fad095a7 | 752 | if (se->cfs_rq == pse->cfs_rq) |
bf0f6f24 IM |
753 | return 1; |
754 | ||
755 | return 0; | |
756 | } | |
757 | ||
fad095a7 SV |
758 | static inline struct sched_entity *parent_entity(struct sched_entity *se) |
759 | { | |
760 | return se->parent; | |
761 | } | |
762 | ||
bf0f6f24 IM |
763 | #else /* CONFIG_FAIR_GROUP_SCHED */ |
764 | ||
765 | #define for_each_sched_entity(se) \ | |
766 | for (; se; se = NULL) | |
767 | ||
768 | static inline struct cfs_rq *task_cfs_rq(struct task_struct *p) | |
769 | { | |
770 | return &task_rq(p)->cfs; | |
771 | } | |
772 | ||
773 | static inline struct cfs_rq *cfs_rq_of(struct sched_entity *se) | |
774 | { | |
775 | struct task_struct *p = task_of(se); | |
776 | struct rq *rq = task_rq(p); | |
777 | ||
778 | return &rq->cfs; | |
779 | } | |
780 | ||
781 | /* runqueue "owned" by this group */ | |
782 | static inline struct cfs_rq *group_cfs_rq(struct sched_entity *grp) | |
783 | { | |
784 | return NULL; | |
785 | } | |
786 | ||
787 | static inline struct cfs_rq *cpu_cfs_rq(struct cfs_rq *cfs_rq, int this_cpu) | |
788 | { | |
789 | return &cpu_rq(this_cpu)->cfs; | |
790 | } | |
791 | ||
792 | #define for_each_leaf_cfs_rq(rq, cfs_rq) \ | |
793 | for (cfs_rq = &rq->cfs; cfs_rq; cfs_rq = NULL) | |
794 | ||
fad095a7 SV |
795 | static inline int |
796 | is_same_group(struct sched_entity *se, struct sched_entity *pse) | |
bf0f6f24 IM |
797 | { |
798 | return 1; | |
799 | } | |
800 | ||
fad095a7 SV |
801 | static inline struct sched_entity *parent_entity(struct sched_entity *se) |
802 | { | |
803 | return NULL; | |
804 | } | |
805 | ||
bf0f6f24 IM |
806 | #endif /* CONFIG_FAIR_GROUP_SCHED */ |
807 | ||
8f4d37ec PZ |
808 | #ifdef CONFIG_SCHED_HRTICK |
809 | static void hrtick_start_fair(struct rq *rq, struct task_struct *p) | |
810 | { | |
811 | int requeue = rq->curr == p; | |
812 | struct sched_entity *se = &p->se; | |
813 | struct cfs_rq *cfs_rq = cfs_rq_of(se); | |
814 | ||
815 | WARN_ON(task_rq(p) != rq); | |
816 | ||
817 | if (hrtick_enabled(rq) && cfs_rq->nr_running > 1) { | |
818 | u64 slice = sched_slice(cfs_rq, se); | |
819 | u64 ran = se->sum_exec_runtime - se->prev_sum_exec_runtime; | |
820 | s64 delta = slice - ran; | |
821 | ||
822 | if (delta < 0) { | |
823 | if (rq->curr == p) | |
824 | resched_task(p); | |
825 | return; | |
826 | } | |
827 | ||
828 | /* | |
829 | * Don't schedule slices shorter than 10000ns, that just | |
830 | * doesn't make sense. Rely on vruntime for fairness. | |
831 | */ | |
832 | if (!requeue) | |
833 | delta = max(10000LL, delta); | |
834 | ||
835 | hrtick_start(rq, delta, requeue); | |
836 | } | |
837 | } | |
838 | #else | |
839 | static inline void | |
840 | hrtick_start_fair(struct rq *rq, struct task_struct *p) | |
841 | { | |
842 | } | |
843 | #endif | |
844 | ||
bf0f6f24 IM |
845 | /* |
846 | * The enqueue_task method is called before nr_running is | |
847 | * increased. Here we update the fair scheduling stats and | |
848 | * then put the task into the rbtree: | |
849 | */ | |
fd390f6a | 850 | static void enqueue_task_fair(struct rq *rq, struct task_struct *p, int wakeup) |
bf0f6f24 IM |
851 | { |
852 | struct cfs_rq *cfs_rq; | |
62fb1851 | 853 | struct sched_entity *se = &p->se; |
bf0f6f24 IM |
854 | |
855 | for_each_sched_entity(se) { | |
62fb1851 | 856 | if (se->on_rq) |
bf0f6f24 IM |
857 | break; |
858 | cfs_rq = cfs_rq_of(se); | |
83b699ed | 859 | enqueue_entity(cfs_rq, se, wakeup); |
b9fa3df3 | 860 | wakeup = 1; |
bf0f6f24 | 861 | } |
8f4d37ec PZ |
862 | |
863 | hrtick_start_fair(rq, rq->curr); | |
bf0f6f24 IM |
864 | } |
865 | ||
866 | /* | |
867 | * The dequeue_task method is called before nr_running is | |
868 | * decreased. We remove the task from the rbtree and | |
869 | * update the fair scheduling stats: | |
870 | */ | |
f02231e5 | 871 | static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int sleep) |
bf0f6f24 IM |
872 | { |
873 | struct cfs_rq *cfs_rq; | |
62fb1851 | 874 | struct sched_entity *se = &p->se; |
bf0f6f24 IM |
875 | |
876 | for_each_sched_entity(se) { | |
877 | cfs_rq = cfs_rq_of(se); | |
525c2716 | 878 | dequeue_entity(cfs_rq, se, sleep); |
bf0f6f24 | 879 | /* Don't dequeue parent if it has other entities besides us */ |
62fb1851 | 880 | if (cfs_rq->load.weight) |
bf0f6f24 | 881 | break; |
b9fa3df3 | 882 | sleep = 1; |
bf0f6f24 | 883 | } |
8f4d37ec PZ |
884 | |
885 | hrtick_start_fair(rq, rq->curr); | |
bf0f6f24 IM |
886 | } |
887 | ||
888 | /* | |
1799e35d IM |
889 | * sched_yield() support is very simple - we dequeue and enqueue. |
890 | * | |
891 | * If compat_yield is turned on then we requeue to the end of the tree. | |
bf0f6f24 | 892 | */ |
4530d7ab | 893 | static void yield_task_fair(struct rq *rq) |
bf0f6f24 | 894 | { |
db292ca3 IM |
895 | struct task_struct *curr = rq->curr; |
896 | struct cfs_rq *cfs_rq = task_cfs_rq(curr); | |
897 | struct sched_entity *rightmost, *se = &curr->se; | |
bf0f6f24 IM |
898 | |
899 | /* | |
1799e35d IM |
900 | * Are we the only task in the tree? |
901 | */ | |
902 | if (unlikely(cfs_rq->nr_running == 1)) | |
903 | return; | |
904 | ||
db292ca3 | 905 | if (likely(!sysctl_sched_compat_yield) && curr->policy != SCHED_BATCH) { |
1799e35d IM |
906 | __update_rq_clock(rq); |
907 | /* | |
a2a2d680 | 908 | * Update run-time statistics of the 'current'. |
1799e35d | 909 | */ |
2b1e315d | 910 | update_curr(cfs_rq); |
1799e35d IM |
911 | |
912 | return; | |
913 | } | |
914 | /* | |
915 | * Find the rightmost entry in the rbtree: | |
bf0f6f24 | 916 | */ |
2b1e315d | 917 | rightmost = __pick_last_entity(cfs_rq); |
1799e35d IM |
918 | /* |
919 | * Already in the rightmost position? | |
920 | */ | |
2b1e315d | 921 | if (unlikely(rightmost->vruntime < se->vruntime)) |
1799e35d IM |
922 | return; |
923 | ||
924 | /* | |
925 | * Minimally necessary key value to be last in the tree: | |
2b1e315d DA |
926 | * Upon rescheduling, sched_class::put_prev_task() will place |
927 | * 'current' within the tree based on its new key value. | |
1799e35d | 928 | */ |
30cfdcfc | 929 | se->vruntime = rightmost->vruntime + 1; |
bf0f6f24 IM |
930 | } |
931 | ||
e7693a36 GH |
932 | /* |
933 | * wake_idle() will wake a task on an idle cpu if task->cpu is | |
934 | * not idle and an idle cpu is available. The span of cpus to | |
935 | * search starts with cpus closest then further out as needed, | |
936 | * so we always favor a closer, idle cpu. | |
937 | * | |
938 | * Returns the CPU we should wake onto. | |
939 | */ | |
940 | #if defined(ARCH_HAS_SCHED_WAKE_IDLE) | |
941 | static int wake_idle(int cpu, struct task_struct *p) | |
942 | { | |
943 | cpumask_t tmp; | |
944 | struct sched_domain *sd; | |
945 | int i; | |
946 | ||
947 | /* | |
948 | * If it is idle, then it is the best cpu to run this task. | |
949 | * | |
950 | * This cpu is also the best, if it has more than one task already. | |
951 | * Siblings must be also busy(in most cases) as they didn't already | |
952 | * pickup the extra load from this cpu and hence we need not check | |
953 | * sibling runqueue info. This will avoid the checks and cache miss | |
954 | * penalities associated with that. | |
955 | */ | |
956 | if (idle_cpu(cpu) || cpu_rq(cpu)->nr_running > 1) | |
957 | return cpu; | |
958 | ||
959 | for_each_domain(cpu, sd) { | |
960 | if (sd->flags & SD_WAKE_IDLE) { | |
961 | cpus_and(tmp, sd->span, p->cpus_allowed); | |
962 | for_each_cpu_mask(i, tmp) { | |
963 | if (idle_cpu(i)) { | |
964 | if (i != task_cpu(p)) { | |
965 | schedstat_inc(p, | |
966 | se.nr_wakeups_idle); | |
967 | } | |
968 | return i; | |
969 | } | |
970 | } | |
971 | } else { | |
972 | break; | |
973 | } | |
974 | } | |
975 | return cpu; | |
976 | } | |
977 | #else | |
978 | static inline int wake_idle(int cpu, struct task_struct *p) | |
979 | { | |
980 | return cpu; | |
981 | } | |
982 | #endif | |
983 | ||
984 | #ifdef CONFIG_SMP | |
098fb9db | 985 | |
4ae7d5ce IM |
986 | static const struct sched_class fair_sched_class; |
987 | ||
098fb9db | 988 | static int |
4ae7d5ce IM |
989 | wake_affine(struct rq *rq, struct sched_domain *this_sd, struct rq *this_rq, |
990 | struct task_struct *p, int prev_cpu, int this_cpu, int sync, | |
991 | int idx, unsigned long load, unsigned long this_load, | |
098fb9db IM |
992 | unsigned int imbalance) |
993 | { | |
4ae7d5ce | 994 | struct task_struct *curr = this_rq->curr; |
098fb9db IM |
995 | unsigned long tl = this_load; |
996 | unsigned long tl_per_task; | |
997 | ||
998 | if (!(this_sd->flags & SD_WAKE_AFFINE)) | |
999 | return 0; | |
1000 | ||
1001 | /* | |
4ae7d5ce IM |
1002 | * If the currently running task will sleep within |
1003 | * a reasonable amount of time then attract this newly | |
1004 | * woken task: | |
098fb9db | 1005 | */ |
4ae7d5ce IM |
1006 | if (sync && curr->sched_class == &fair_sched_class) { |
1007 | if (curr->se.avg_overlap < sysctl_sched_migration_cost && | |
1008 | p->se.avg_overlap < sysctl_sched_migration_cost) | |
1009 | return 1; | |
1010 | } | |
098fb9db IM |
1011 | |
1012 | schedstat_inc(p, se.nr_wakeups_affine_attempts); | |
1013 | tl_per_task = cpu_avg_load_per_task(this_cpu); | |
1014 | ||
1015 | /* | |
1016 | * If sync wakeup then subtract the (maximum possible) | |
1017 | * effect of the currently running task from the load | |
1018 | * of the current CPU: | |
1019 | */ | |
1020 | if (sync) | |
1021 | tl -= current->se.load.weight; | |
1022 | ||
ac192d39 | 1023 | if ((tl <= load && tl + target_load(prev_cpu, idx) <= tl_per_task) || |
098fb9db IM |
1024 | 100*(tl + p->se.load.weight) <= imbalance*load) { |
1025 | /* | |
1026 | * This domain has SD_WAKE_AFFINE and | |
1027 | * p is cache cold in this domain, and | |
1028 | * there is no bad imbalance. | |
1029 | */ | |
1030 | schedstat_inc(this_sd, ttwu_move_affine); | |
1031 | schedstat_inc(p, se.nr_wakeups_affine); | |
1032 | ||
1033 | return 1; | |
1034 | } | |
1035 | return 0; | |
1036 | } | |
1037 | ||
e7693a36 GH |
1038 | static int select_task_rq_fair(struct task_struct *p, int sync) |
1039 | { | |
e7693a36 | 1040 | struct sched_domain *sd, *this_sd = NULL; |
ac192d39 | 1041 | int prev_cpu, this_cpu, new_cpu; |
098fb9db | 1042 | unsigned long load, this_load; |
4ae7d5ce | 1043 | struct rq *rq, *this_rq; |
098fb9db | 1044 | unsigned int imbalance; |
098fb9db | 1045 | int idx; |
e7693a36 | 1046 | |
ac192d39 IM |
1047 | prev_cpu = task_cpu(p); |
1048 | rq = task_rq(p); | |
1049 | this_cpu = smp_processor_id(); | |
4ae7d5ce | 1050 | this_rq = cpu_rq(this_cpu); |
ac192d39 | 1051 | new_cpu = prev_cpu; |
e7693a36 | 1052 | |
ac192d39 IM |
1053 | /* |
1054 | * 'this_sd' is the first domain that both | |
1055 | * this_cpu and prev_cpu are present in: | |
1056 | */ | |
e7693a36 | 1057 | for_each_domain(this_cpu, sd) { |
ac192d39 | 1058 | if (cpu_isset(prev_cpu, sd->span)) { |
e7693a36 GH |
1059 | this_sd = sd; |
1060 | break; | |
1061 | } | |
1062 | } | |
1063 | ||
1064 | if (unlikely(!cpu_isset(this_cpu, p->cpus_allowed))) | |
f4827386 | 1065 | goto out; |
e7693a36 GH |
1066 | |
1067 | /* | |
1068 | * Check for affine wakeup and passive balancing possibilities. | |
1069 | */ | |
098fb9db | 1070 | if (!this_sd) |
f4827386 | 1071 | goto out; |
e7693a36 | 1072 | |
098fb9db IM |
1073 | idx = this_sd->wake_idx; |
1074 | ||
1075 | imbalance = 100 + (this_sd->imbalance_pct - 100) / 2; | |
1076 | ||
ac192d39 | 1077 | load = source_load(prev_cpu, idx); |
098fb9db IM |
1078 | this_load = target_load(this_cpu, idx); |
1079 | ||
4ae7d5ce IM |
1080 | if (wake_affine(rq, this_sd, this_rq, p, prev_cpu, this_cpu, sync, idx, |
1081 | load, this_load, imbalance)) | |
1082 | return this_cpu; | |
1083 | ||
1084 | if (prev_cpu == this_cpu) | |
f4827386 | 1085 | goto out; |
098fb9db IM |
1086 | |
1087 | /* | |
1088 | * Start passive balancing when half the imbalance_pct | |
1089 | * limit is reached. | |
1090 | */ | |
1091 | if (this_sd->flags & SD_WAKE_BALANCE) { | |
1092 | if (imbalance*this_load <= 100*load) { | |
1093 | schedstat_inc(this_sd, ttwu_move_balance); | |
1094 | schedstat_inc(p, se.nr_wakeups_passive); | |
4ae7d5ce | 1095 | return this_cpu; |
e7693a36 GH |
1096 | } |
1097 | } | |
1098 | ||
f4827386 | 1099 | out: |
e7693a36 GH |
1100 | return wake_idle(new_cpu, p); |
1101 | } | |
1102 | #endif /* CONFIG_SMP */ | |
1103 | ||
1104 | ||
bf0f6f24 IM |
1105 | /* |
1106 | * Preempt the current task with a newly woken task if needed: | |
1107 | */ | |
2e09bf55 | 1108 | static void check_preempt_wakeup(struct rq *rq, struct task_struct *p) |
bf0f6f24 IM |
1109 | { |
1110 | struct task_struct *curr = rq->curr; | |
fad095a7 | 1111 | struct cfs_rq *cfs_rq = task_cfs_rq(curr); |
8651a86c | 1112 | struct sched_entity *se = &curr->se, *pse = &p->se; |
502d26b5 | 1113 | unsigned long gran; |
bf0f6f24 IM |
1114 | |
1115 | if (unlikely(rt_prio(p->prio))) { | |
a8e504d2 | 1116 | update_rq_clock(rq); |
b7cc0896 | 1117 | update_curr(cfs_rq); |
bf0f6f24 IM |
1118 | resched_task(curr); |
1119 | return; | |
1120 | } | |
aa2ac252 | 1121 | |
4ae7d5ce IM |
1122 | se->last_wakeup = se->sum_exec_runtime; |
1123 | if (unlikely(se == pse)) | |
1124 | return; | |
1125 | ||
aa2ac252 PZ |
1126 | cfs_rq_of(pse)->next = pse; |
1127 | ||
91c234b4 IM |
1128 | /* |
1129 | * Batch tasks do not preempt (their preemption is driven by | |
1130 | * the tick): | |
1131 | */ | |
1132 | if (unlikely(p->policy == SCHED_BATCH)) | |
1133 | return; | |
bf0f6f24 | 1134 | |
77d9cc44 IM |
1135 | if (!sched_feat(WAKEUP_PREEMPT)) |
1136 | return; | |
8651a86c | 1137 | |
77d9cc44 IM |
1138 | while (!is_same_group(se, pse)) { |
1139 | se = parent_entity(se); | |
1140 | pse = parent_entity(pse); | |
ce6c1311 | 1141 | } |
77d9cc44 | 1142 | |
77d9cc44 | 1143 | gran = sysctl_sched_wakeup_granularity; |
ef9884e6 PZ |
1144 | /* |
1145 | * More easily preempt - nice tasks, while not making | |
1146 | * it harder for + nice tasks. | |
1147 | */ | |
1148 | if (unlikely(se->load.weight > NICE_0_LOAD)) | |
77d9cc44 IM |
1149 | gran = calc_delta_fair(gran, &se->load); |
1150 | ||
502d26b5 | 1151 | if (pse->vruntime + gran < se->vruntime) |
77d9cc44 | 1152 | resched_task(curr); |
bf0f6f24 IM |
1153 | } |
1154 | ||
fb8d4724 | 1155 | static struct task_struct *pick_next_task_fair(struct rq *rq) |
bf0f6f24 | 1156 | { |
8f4d37ec | 1157 | struct task_struct *p; |
bf0f6f24 IM |
1158 | struct cfs_rq *cfs_rq = &rq->cfs; |
1159 | struct sched_entity *se; | |
1160 | ||
1161 | if (unlikely(!cfs_rq->nr_running)) | |
1162 | return NULL; | |
1163 | ||
1164 | do { | |
9948f4b2 | 1165 | se = pick_next_entity(cfs_rq); |
bf0f6f24 IM |
1166 | cfs_rq = group_cfs_rq(se); |
1167 | } while (cfs_rq); | |
1168 | ||
8f4d37ec PZ |
1169 | p = task_of(se); |
1170 | hrtick_start_fair(rq, p); | |
1171 | ||
1172 | return p; | |
bf0f6f24 IM |
1173 | } |
1174 | ||
1175 | /* | |
1176 | * Account for a descheduled task: | |
1177 | */ | |
31ee529c | 1178 | static void put_prev_task_fair(struct rq *rq, struct task_struct *prev) |
bf0f6f24 IM |
1179 | { |
1180 | struct sched_entity *se = &prev->se; | |
1181 | struct cfs_rq *cfs_rq; | |
1182 | ||
1183 | for_each_sched_entity(se) { | |
1184 | cfs_rq = cfs_rq_of(se); | |
ab6cde26 | 1185 | put_prev_entity(cfs_rq, se); |
bf0f6f24 IM |
1186 | } |
1187 | } | |
1188 | ||
681f3e68 | 1189 | #ifdef CONFIG_SMP |
bf0f6f24 IM |
1190 | /************************************************** |
1191 | * Fair scheduling class load-balancing methods: | |
1192 | */ | |
1193 | ||
1194 | /* | |
1195 | * Load-balancing iterator. Note: while the runqueue stays locked | |
1196 | * during the whole iteration, the current task might be | |
1197 | * dequeued so the iterator has to be dequeue-safe. Here we | |
1198 | * achieve that by always pre-iterating before returning | |
1199 | * the current task: | |
1200 | */ | |
a9957449 | 1201 | static struct task_struct * |
bf0f6f24 IM |
1202 | __load_balance_iterator(struct cfs_rq *cfs_rq, struct rb_node *curr) |
1203 | { | |
1204 | struct task_struct *p; | |
1205 | ||
1206 | if (!curr) | |
1207 | return NULL; | |
1208 | ||
1209 | p = rb_entry(curr, struct task_struct, se.run_node); | |
1210 | cfs_rq->rb_load_balance_curr = rb_next(curr); | |
1211 | ||
1212 | return p; | |
1213 | } | |
1214 | ||
1215 | static struct task_struct *load_balance_start_fair(void *arg) | |
1216 | { | |
1217 | struct cfs_rq *cfs_rq = arg; | |
1218 | ||
1219 | return __load_balance_iterator(cfs_rq, first_fair(cfs_rq)); | |
1220 | } | |
1221 | ||
1222 | static struct task_struct *load_balance_next_fair(void *arg) | |
1223 | { | |
1224 | struct cfs_rq *cfs_rq = arg; | |
1225 | ||
1226 | return __load_balance_iterator(cfs_rq, cfs_rq->rb_load_balance_curr); | |
1227 | } | |
1228 | ||
62fb1851 PZ |
1229 | #ifdef CONFIG_FAIR_GROUP_SCHED |
1230 | static int cfs_rq_best_prio(struct cfs_rq *cfs_rq) | |
1231 | { | |
1232 | struct sched_entity *curr; | |
1233 | struct task_struct *p; | |
1234 | ||
1235 | if (!cfs_rq->nr_running || !first_fair(cfs_rq)) | |
1236 | return MAX_PRIO; | |
1237 | ||
1238 | curr = cfs_rq->curr; | |
1239 | if (!curr) | |
1240 | curr = __pick_next_entity(cfs_rq); | |
1241 | ||
1242 | p = task_of(curr); | |
1243 | ||
1244 | return p->prio; | |
1245 | } | |
1246 | #endif | |
1247 | ||
43010659 | 1248 | static unsigned long |
bf0f6f24 | 1249 | load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest, |
e1d1484f | 1250 | unsigned long max_load_move, |
a4ac01c3 PW |
1251 | struct sched_domain *sd, enum cpu_idle_type idle, |
1252 | int *all_pinned, int *this_best_prio) | |
bf0f6f24 IM |
1253 | { |
1254 | struct cfs_rq *busy_cfs_rq; | |
bf0f6f24 IM |
1255 | long rem_load_move = max_load_move; |
1256 | struct rq_iterator cfs_rq_iterator; | |
1257 | ||
1258 | cfs_rq_iterator.start = load_balance_start_fair; | |
1259 | cfs_rq_iterator.next = load_balance_next_fair; | |
1260 | ||
1261 | for_each_leaf_cfs_rq(busiest, busy_cfs_rq) { | |
a4ac01c3 | 1262 | #ifdef CONFIG_FAIR_GROUP_SCHED |
62fb1851 PZ |
1263 | struct cfs_rq *this_cfs_rq; |
1264 | long imbalance; | |
1265 | unsigned long maxload; | |
bf0f6f24 | 1266 | |
62fb1851 | 1267 | this_cfs_rq = cpu_cfs_rq(busy_cfs_rq, this_cpu); |
6b2d7700 | 1268 | |
62fb1851 PZ |
1269 | imbalance = busy_cfs_rq->load.weight - this_cfs_rq->load.weight; |
1270 | /* Don't pull if this_cfs_rq has more load than busy_cfs_rq */ | |
1271 | if (imbalance <= 0) | |
bf0f6f24 IM |
1272 | continue; |
1273 | ||
62fb1851 PZ |
1274 | /* Don't pull more than imbalance/2 */ |
1275 | imbalance /= 2; | |
1276 | maxload = min(rem_load_move, imbalance); | |
bf0f6f24 | 1277 | |
62fb1851 | 1278 | *this_best_prio = cfs_rq_best_prio(this_cfs_rq); |
a4ac01c3 | 1279 | #else |
e56f31aa | 1280 | # define maxload rem_load_move |
a4ac01c3 | 1281 | #endif |
e1d1484f PW |
1282 | /* |
1283 | * pass busy_cfs_rq argument into | |
bf0f6f24 IM |
1284 | * load_balance_[start|next]_fair iterators |
1285 | */ | |
1286 | cfs_rq_iterator.arg = busy_cfs_rq; | |
62fb1851 | 1287 | rem_load_move -= balance_tasks(this_rq, this_cpu, busiest, |
e1d1484f PW |
1288 | maxload, sd, idle, all_pinned, |
1289 | this_best_prio, | |
1290 | &cfs_rq_iterator); | |
bf0f6f24 | 1291 | |
e1d1484f | 1292 | if (rem_load_move <= 0) |
bf0f6f24 IM |
1293 | break; |
1294 | } | |
1295 | ||
43010659 | 1296 | return max_load_move - rem_load_move; |
bf0f6f24 IM |
1297 | } |
1298 | ||
e1d1484f PW |
1299 | static int |
1300 | move_one_task_fair(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
1301 | struct sched_domain *sd, enum cpu_idle_type idle) | |
1302 | { | |
1303 | struct cfs_rq *busy_cfs_rq; | |
1304 | struct rq_iterator cfs_rq_iterator; | |
1305 | ||
1306 | cfs_rq_iterator.start = load_balance_start_fair; | |
1307 | cfs_rq_iterator.next = load_balance_next_fair; | |
1308 | ||
1309 | for_each_leaf_cfs_rq(busiest, busy_cfs_rq) { | |
1310 | /* | |
1311 | * pass busy_cfs_rq argument into | |
1312 | * load_balance_[start|next]_fair iterators | |
1313 | */ | |
1314 | cfs_rq_iterator.arg = busy_cfs_rq; | |
1315 | if (iter_move_one_task(this_rq, this_cpu, busiest, sd, idle, | |
1316 | &cfs_rq_iterator)) | |
1317 | return 1; | |
1318 | } | |
1319 | ||
1320 | return 0; | |
1321 | } | |
681f3e68 | 1322 | #endif |
e1d1484f | 1323 | |
bf0f6f24 IM |
1324 | /* |
1325 | * scheduler tick hitting a task of our scheduling class: | |
1326 | */ | |
8f4d37ec | 1327 | static void task_tick_fair(struct rq *rq, struct task_struct *curr, int queued) |
bf0f6f24 IM |
1328 | { |
1329 | struct cfs_rq *cfs_rq; | |
1330 | struct sched_entity *se = &curr->se; | |
1331 | ||
1332 | for_each_sched_entity(se) { | |
1333 | cfs_rq = cfs_rq_of(se); | |
8f4d37ec | 1334 | entity_tick(cfs_rq, se, queued); |
bf0f6f24 IM |
1335 | } |
1336 | } | |
1337 | ||
8eb172d9 | 1338 | #define swap(a, b) do { typeof(a) tmp = (a); (a) = (b); (b) = tmp; } while (0) |
4d78e7b6 | 1339 | |
bf0f6f24 IM |
1340 | /* |
1341 | * Share the fairness runtime between parent and child, thus the | |
1342 | * total amount of pressure for CPU stays equal - new tasks | |
1343 | * get a chance to run but frequent forkers are not allowed to | |
1344 | * monopolize the CPU. Note: the parent runqueue is locked, | |
1345 | * the child is not running yet. | |
1346 | */ | |
ee0827d8 | 1347 | static void task_new_fair(struct rq *rq, struct task_struct *p) |
bf0f6f24 IM |
1348 | { |
1349 | struct cfs_rq *cfs_rq = task_cfs_rq(p); | |
429d43bc | 1350 | struct sched_entity *se = &p->se, *curr = cfs_rq->curr; |
00bf7bfc | 1351 | int this_cpu = smp_processor_id(); |
bf0f6f24 IM |
1352 | |
1353 | sched_info_queued(p); | |
1354 | ||
7109c442 | 1355 | update_curr(cfs_rq); |
aeb73b04 | 1356 | place_entity(cfs_rq, se, 1); |
4d78e7b6 | 1357 | |
3c90e6e9 | 1358 | /* 'curr' will be NULL if the child belongs to a different group */ |
00bf7bfc | 1359 | if (sysctl_sched_child_runs_first && this_cpu == task_cpu(p) && |
3c90e6e9 | 1360 | curr && curr->vruntime < se->vruntime) { |
87fefa38 | 1361 | /* |
edcb60a3 IM |
1362 | * Upon rescheduling, sched_class::put_prev_task() will place |
1363 | * 'current' within the tree based on its new key value. | |
1364 | */ | |
4d78e7b6 | 1365 | swap(curr->vruntime, se->vruntime); |
4d78e7b6 | 1366 | } |
bf0f6f24 | 1367 | |
b9dca1e0 | 1368 | enqueue_task_fair(rq, p, 0); |
bb61c210 | 1369 | resched_task(rq->curr); |
bf0f6f24 IM |
1370 | } |
1371 | ||
cb469845 SR |
1372 | /* |
1373 | * Priority of the task has changed. Check to see if we preempt | |
1374 | * the current task. | |
1375 | */ | |
1376 | static void prio_changed_fair(struct rq *rq, struct task_struct *p, | |
1377 | int oldprio, int running) | |
1378 | { | |
1379 | /* | |
1380 | * Reschedule if we are currently running on this runqueue and | |
1381 | * our priority decreased, or if we are not currently running on | |
1382 | * this runqueue and our priority is higher than the current's | |
1383 | */ | |
1384 | if (running) { | |
1385 | if (p->prio > oldprio) | |
1386 | resched_task(rq->curr); | |
1387 | } else | |
1388 | check_preempt_curr(rq, p); | |
1389 | } | |
1390 | ||
1391 | /* | |
1392 | * We switched to the sched_fair class. | |
1393 | */ | |
1394 | static void switched_to_fair(struct rq *rq, struct task_struct *p, | |
1395 | int running) | |
1396 | { | |
1397 | /* | |
1398 | * We were most likely switched from sched_rt, so | |
1399 | * kick off the schedule if running, otherwise just see | |
1400 | * if we can still preempt the current task. | |
1401 | */ | |
1402 | if (running) | |
1403 | resched_task(rq->curr); | |
1404 | else | |
1405 | check_preempt_curr(rq, p); | |
1406 | } | |
1407 | ||
83b699ed SV |
1408 | /* Account for a task changing its policy or group. |
1409 | * | |
1410 | * This routine is mostly called to set cfs_rq->curr field when a task | |
1411 | * migrates between groups/classes. | |
1412 | */ | |
1413 | static void set_curr_task_fair(struct rq *rq) | |
1414 | { | |
1415 | struct sched_entity *se = &rq->curr->se; | |
1416 | ||
1417 | for_each_sched_entity(se) | |
1418 | set_next_entity(cfs_rq_of(se), se); | |
1419 | } | |
1420 | ||
810b3817 PZ |
1421 | #ifdef CONFIG_FAIR_GROUP_SCHED |
1422 | static void moved_group_fair(struct task_struct *p) | |
1423 | { | |
1424 | struct cfs_rq *cfs_rq = task_cfs_rq(p); | |
1425 | ||
1426 | update_curr(cfs_rq); | |
1427 | place_entity(cfs_rq, &p->se, 1); | |
1428 | } | |
1429 | #endif | |
1430 | ||
bf0f6f24 IM |
1431 | /* |
1432 | * All the scheduling class methods: | |
1433 | */ | |
5522d5d5 IM |
1434 | static const struct sched_class fair_sched_class = { |
1435 | .next = &idle_sched_class, | |
bf0f6f24 IM |
1436 | .enqueue_task = enqueue_task_fair, |
1437 | .dequeue_task = dequeue_task_fair, | |
1438 | .yield_task = yield_task_fair, | |
e7693a36 GH |
1439 | #ifdef CONFIG_SMP |
1440 | .select_task_rq = select_task_rq_fair, | |
1441 | #endif /* CONFIG_SMP */ | |
bf0f6f24 | 1442 | |
2e09bf55 | 1443 | .check_preempt_curr = check_preempt_wakeup, |
bf0f6f24 IM |
1444 | |
1445 | .pick_next_task = pick_next_task_fair, | |
1446 | .put_prev_task = put_prev_task_fair, | |
1447 | ||
681f3e68 | 1448 | #ifdef CONFIG_SMP |
bf0f6f24 | 1449 | .load_balance = load_balance_fair, |
e1d1484f | 1450 | .move_one_task = move_one_task_fair, |
681f3e68 | 1451 | #endif |
bf0f6f24 | 1452 | |
83b699ed | 1453 | .set_curr_task = set_curr_task_fair, |
bf0f6f24 IM |
1454 | .task_tick = task_tick_fair, |
1455 | .task_new = task_new_fair, | |
cb469845 SR |
1456 | |
1457 | .prio_changed = prio_changed_fair, | |
1458 | .switched_to = switched_to_fair, | |
810b3817 PZ |
1459 | |
1460 | #ifdef CONFIG_FAIR_GROUP_SCHED | |
1461 | .moved_group = moved_group_fair, | |
1462 | #endif | |
bf0f6f24 IM |
1463 | }; |
1464 | ||
1465 | #ifdef CONFIG_SCHED_DEBUG | |
5cef9eca | 1466 | static void print_cfs_stats(struct seq_file *m, int cpu) |
bf0f6f24 | 1467 | { |
bf0f6f24 IM |
1468 | struct cfs_rq *cfs_rq; |
1469 | ||
75c28ace SV |
1470 | #ifdef CONFIG_FAIR_GROUP_SCHED |
1471 | print_cfs_rq(m, cpu, &cpu_rq(cpu)->cfs); | |
1472 | #endif | |
5973e5b9 | 1473 | rcu_read_lock(); |
c3b64f1e | 1474 | for_each_leaf_cfs_rq(cpu_rq(cpu), cfs_rq) |
5cef9eca | 1475 | print_cfs_rq(m, cpu, cfs_rq); |
5973e5b9 | 1476 | rcu_read_unlock(); |
bf0f6f24 IM |
1477 | } |
1478 | #endif |