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. | |
103638d9 | 66 | * (default: 5 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 | */ | |
103638d9 | 72 | unsigned int sysctl_sched_wakeup_granularity = 5000000UL; |
bf0f6f24 | 73 | |
da84d961 IM |
74 | const_debug unsigned int sysctl_sched_migration_cost = 500000UL; |
75 | ||
a4c2f00f PZ |
76 | static const struct sched_class fair_sched_class; |
77 | ||
bf0f6f24 IM |
78 | /************************************************************** |
79 | * CFS operations on generic schedulable entities: | |
80 | */ | |
81 | ||
b758149c PZ |
82 | static inline struct task_struct *task_of(struct sched_entity *se) |
83 | { | |
84 | return container_of(se, struct task_struct, se); | |
85 | } | |
86 | ||
62160e3f | 87 | #ifdef CONFIG_FAIR_GROUP_SCHED |
bf0f6f24 | 88 | |
62160e3f | 89 | /* cpu runqueue to which this cfs_rq is attached */ |
bf0f6f24 IM |
90 | static inline struct rq *rq_of(struct cfs_rq *cfs_rq) |
91 | { | |
62160e3f | 92 | return cfs_rq->rq; |
bf0f6f24 IM |
93 | } |
94 | ||
62160e3f IM |
95 | /* An entity is a task if it doesn't "own" a runqueue */ |
96 | #define entity_is_task(se) (!se->my_q) | |
bf0f6f24 | 97 | |
b758149c PZ |
98 | /* Walk up scheduling entities hierarchy */ |
99 | #define for_each_sched_entity(se) \ | |
100 | for (; se; se = se->parent) | |
101 | ||
102 | static inline struct cfs_rq *task_cfs_rq(struct task_struct *p) | |
103 | { | |
104 | return p->se.cfs_rq; | |
105 | } | |
106 | ||
107 | /* runqueue on which this entity is (to be) queued */ | |
108 | static inline struct cfs_rq *cfs_rq_of(struct sched_entity *se) | |
109 | { | |
110 | return se->cfs_rq; | |
111 | } | |
112 | ||
113 | /* runqueue "owned" by this group */ | |
114 | static inline struct cfs_rq *group_cfs_rq(struct sched_entity *grp) | |
115 | { | |
116 | return grp->my_q; | |
117 | } | |
118 | ||
119 | /* Given a group's cfs_rq on one cpu, return its corresponding cfs_rq on | |
120 | * another cpu ('this_cpu') | |
121 | */ | |
122 | static inline struct cfs_rq *cpu_cfs_rq(struct cfs_rq *cfs_rq, int this_cpu) | |
123 | { | |
124 | return cfs_rq->tg->cfs_rq[this_cpu]; | |
125 | } | |
126 | ||
127 | /* Iterate thr' all leaf cfs_rq's on a runqueue */ | |
128 | #define for_each_leaf_cfs_rq(rq, cfs_rq) \ | |
129 | list_for_each_entry_rcu(cfs_rq, &rq->leaf_cfs_rq_list, leaf_cfs_rq_list) | |
130 | ||
131 | /* Do the two (enqueued) entities belong to the same group ? */ | |
132 | static inline int | |
133 | is_same_group(struct sched_entity *se, struct sched_entity *pse) | |
134 | { | |
135 | if (se->cfs_rq == pse->cfs_rq) | |
136 | return 1; | |
137 | ||
138 | return 0; | |
139 | } | |
140 | ||
141 | static inline struct sched_entity *parent_entity(struct sched_entity *se) | |
142 | { | |
143 | return se->parent; | |
144 | } | |
145 | ||
464b7527 PZ |
146 | /* return depth at which a sched entity is present in the hierarchy */ |
147 | static inline int depth_se(struct sched_entity *se) | |
148 | { | |
149 | int depth = 0; | |
150 | ||
151 | for_each_sched_entity(se) | |
152 | depth++; | |
153 | ||
154 | return depth; | |
155 | } | |
156 | ||
157 | static void | |
158 | find_matching_se(struct sched_entity **se, struct sched_entity **pse) | |
159 | { | |
160 | int se_depth, pse_depth; | |
161 | ||
162 | /* | |
163 | * preemption test can be made between sibling entities who are in the | |
164 | * same cfs_rq i.e who have a common parent. Walk up the hierarchy of | |
165 | * both tasks until we find their ancestors who are siblings of common | |
166 | * parent. | |
167 | */ | |
168 | ||
169 | /* First walk up until both entities are at same depth */ | |
170 | se_depth = depth_se(*se); | |
171 | pse_depth = depth_se(*pse); | |
172 | ||
173 | while (se_depth > pse_depth) { | |
174 | se_depth--; | |
175 | *se = parent_entity(*se); | |
176 | } | |
177 | ||
178 | while (pse_depth > se_depth) { | |
179 | pse_depth--; | |
180 | *pse = parent_entity(*pse); | |
181 | } | |
182 | ||
183 | while (!is_same_group(*se, *pse)) { | |
184 | *se = parent_entity(*se); | |
185 | *pse = parent_entity(*pse); | |
186 | } | |
187 | } | |
188 | ||
62160e3f | 189 | #else /* CONFIG_FAIR_GROUP_SCHED */ |
bf0f6f24 | 190 | |
62160e3f IM |
191 | static inline struct rq *rq_of(struct cfs_rq *cfs_rq) |
192 | { | |
193 | return container_of(cfs_rq, struct rq, cfs); | |
bf0f6f24 IM |
194 | } |
195 | ||
196 | #define entity_is_task(se) 1 | |
197 | ||
b758149c PZ |
198 | #define for_each_sched_entity(se) \ |
199 | for (; se; se = NULL) | |
bf0f6f24 | 200 | |
b758149c | 201 | static inline struct cfs_rq *task_cfs_rq(struct task_struct *p) |
bf0f6f24 | 202 | { |
b758149c | 203 | return &task_rq(p)->cfs; |
bf0f6f24 IM |
204 | } |
205 | ||
b758149c PZ |
206 | static inline struct cfs_rq *cfs_rq_of(struct sched_entity *se) |
207 | { | |
208 | struct task_struct *p = task_of(se); | |
209 | struct rq *rq = task_rq(p); | |
210 | ||
211 | return &rq->cfs; | |
212 | } | |
213 | ||
214 | /* runqueue "owned" by this group */ | |
215 | static inline struct cfs_rq *group_cfs_rq(struct sched_entity *grp) | |
216 | { | |
217 | return NULL; | |
218 | } | |
219 | ||
220 | static inline struct cfs_rq *cpu_cfs_rq(struct cfs_rq *cfs_rq, int this_cpu) | |
221 | { | |
222 | return &cpu_rq(this_cpu)->cfs; | |
223 | } | |
224 | ||
225 | #define for_each_leaf_cfs_rq(rq, cfs_rq) \ | |
226 | for (cfs_rq = &rq->cfs; cfs_rq; cfs_rq = NULL) | |
227 | ||
228 | static inline int | |
229 | is_same_group(struct sched_entity *se, struct sched_entity *pse) | |
230 | { | |
231 | return 1; | |
232 | } | |
233 | ||
234 | static inline struct sched_entity *parent_entity(struct sched_entity *se) | |
235 | { | |
236 | return NULL; | |
237 | } | |
238 | ||
464b7527 PZ |
239 | static inline void |
240 | find_matching_se(struct sched_entity **se, struct sched_entity **pse) | |
241 | { | |
242 | } | |
243 | ||
b758149c PZ |
244 | #endif /* CONFIG_FAIR_GROUP_SCHED */ |
245 | ||
bf0f6f24 IM |
246 | |
247 | /************************************************************** | |
248 | * Scheduling class tree data structure manipulation methods: | |
249 | */ | |
250 | ||
0702e3eb | 251 | static inline u64 max_vruntime(u64 min_vruntime, u64 vruntime) |
02e0431a | 252 | { |
368059a9 PZ |
253 | s64 delta = (s64)(vruntime - min_vruntime); |
254 | if (delta > 0) | |
02e0431a PZ |
255 | min_vruntime = vruntime; |
256 | ||
257 | return min_vruntime; | |
258 | } | |
259 | ||
0702e3eb | 260 | static inline u64 min_vruntime(u64 min_vruntime, u64 vruntime) |
b0ffd246 PZ |
261 | { |
262 | s64 delta = (s64)(vruntime - min_vruntime); | |
263 | if (delta < 0) | |
264 | min_vruntime = vruntime; | |
265 | ||
266 | return min_vruntime; | |
267 | } | |
268 | ||
0702e3eb | 269 | static inline s64 entity_key(struct cfs_rq *cfs_rq, struct sched_entity *se) |
9014623c | 270 | { |
30cfdcfc | 271 | return se->vruntime - cfs_rq->min_vruntime; |
9014623c PZ |
272 | } |
273 | ||
1af5f730 PZ |
274 | static void update_min_vruntime(struct cfs_rq *cfs_rq) |
275 | { | |
276 | u64 vruntime = cfs_rq->min_vruntime; | |
277 | ||
278 | if (cfs_rq->curr) | |
279 | vruntime = cfs_rq->curr->vruntime; | |
280 | ||
281 | if (cfs_rq->rb_leftmost) { | |
282 | struct sched_entity *se = rb_entry(cfs_rq->rb_leftmost, | |
283 | struct sched_entity, | |
284 | run_node); | |
285 | ||
286 | if (vruntime == cfs_rq->min_vruntime) | |
287 | vruntime = se->vruntime; | |
288 | else | |
289 | vruntime = min_vruntime(vruntime, se->vruntime); | |
290 | } | |
291 | ||
292 | cfs_rq->min_vruntime = max_vruntime(cfs_rq->min_vruntime, vruntime); | |
293 | } | |
294 | ||
bf0f6f24 IM |
295 | /* |
296 | * Enqueue an entity into the rb-tree: | |
297 | */ | |
0702e3eb | 298 | static void __enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 IM |
299 | { |
300 | struct rb_node **link = &cfs_rq->tasks_timeline.rb_node; | |
301 | struct rb_node *parent = NULL; | |
302 | struct sched_entity *entry; | |
9014623c | 303 | s64 key = entity_key(cfs_rq, se); |
bf0f6f24 IM |
304 | int leftmost = 1; |
305 | ||
306 | /* | |
307 | * Find the right place in the rbtree: | |
308 | */ | |
309 | while (*link) { | |
310 | parent = *link; | |
311 | entry = rb_entry(parent, struct sched_entity, run_node); | |
312 | /* | |
313 | * We dont care about collisions. Nodes with | |
314 | * the same key stay together. | |
315 | */ | |
9014623c | 316 | if (key < entity_key(cfs_rq, entry)) { |
bf0f6f24 IM |
317 | link = &parent->rb_left; |
318 | } else { | |
319 | link = &parent->rb_right; | |
320 | leftmost = 0; | |
321 | } | |
322 | } | |
323 | ||
324 | /* | |
325 | * Maintain a cache of leftmost tree entries (it is frequently | |
326 | * used): | |
327 | */ | |
1af5f730 | 328 | if (leftmost) |
57cb499d | 329 | cfs_rq->rb_leftmost = &se->run_node; |
bf0f6f24 IM |
330 | |
331 | rb_link_node(&se->run_node, parent, link); | |
332 | rb_insert_color(&se->run_node, &cfs_rq->tasks_timeline); | |
bf0f6f24 IM |
333 | } |
334 | ||
0702e3eb | 335 | static void __dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 336 | { |
3fe69747 PZ |
337 | if (cfs_rq->rb_leftmost == &se->run_node) { |
338 | struct rb_node *next_node; | |
3fe69747 PZ |
339 | |
340 | next_node = rb_next(&se->run_node); | |
341 | cfs_rq->rb_leftmost = next_node; | |
3fe69747 | 342 | } |
e9acbff6 | 343 | |
bf0f6f24 | 344 | rb_erase(&se->run_node, &cfs_rq->tasks_timeline); |
bf0f6f24 IM |
345 | } |
346 | ||
bf0f6f24 IM |
347 | static struct sched_entity *__pick_next_entity(struct cfs_rq *cfs_rq) |
348 | { | |
f4b6755f PZ |
349 | struct rb_node *left = cfs_rq->rb_leftmost; |
350 | ||
351 | if (!left) | |
352 | return NULL; | |
353 | ||
354 | return rb_entry(left, struct sched_entity, run_node); | |
bf0f6f24 IM |
355 | } |
356 | ||
f4b6755f | 357 | static struct sched_entity *__pick_last_entity(struct cfs_rq *cfs_rq) |
aeb73b04 | 358 | { |
7eee3e67 | 359 | struct rb_node *last = rb_last(&cfs_rq->tasks_timeline); |
aeb73b04 | 360 | |
70eee74b BS |
361 | if (!last) |
362 | return NULL; | |
7eee3e67 IM |
363 | |
364 | return rb_entry(last, struct sched_entity, run_node); | |
aeb73b04 PZ |
365 | } |
366 | ||
bf0f6f24 IM |
367 | /************************************************************** |
368 | * Scheduling class statistics methods: | |
369 | */ | |
370 | ||
b2be5e96 PZ |
371 | #ifdef CONFIG_SCHED_DEBUG |
372 | int sched_nr_latency_handler(struct ctl_table *table, int write, | |
373 | struct file *filp, void __user *buffer, size_t *lenp, | |
374 | loff_t *ppos) | |
375 | { | |
376 | int ret = proc_dointvec_minmax(table, write, filp, buffer, lenp, ppos); | |
377 | ||
378 | if (ret || !write) | |
379 | return ret; | |
380 | ||
381 | sched_nr_latency = DIV_ROUND_UP(sysctl_sched_latency, | |
382 | sysctl_sched_min_granularity); | |
383 | ||
384 | return 0; | |
385 | } | |
386 | #endif | |
647e7cac | 387 | |
a7be37ac | 388 | /* |
f9c0b095 | 389 | * delta *= P[w / rw] |
a7be37ac PZ |
390 | */ |
391 | static inline unsigned long | |
392 | calc_delta_weight(unsigned long delta, struct sched_entity *se) | |
393 | { | |
394 | for_each_sched_entity(se) { | |
395 | delta = calc_delta_mine(delta, | |
396 | se->load.weight, &cfs_rq_of(se)->load); | |
397 | } | |
398 | ||
399 | return delta; | |
400 | } | |
401 | ||
402 | /* | |
f9c0b095 | 403 | * delta /= w |
a7be37ac PZ |
404 | */ |
405 | static inline unsigned long | |
406 | calc_delta_fair(unsigned long delta, struct sched_entity *se) | |
407 | { | |
f9c0b095 PZ |
408 | if (unlikely(se->load.weight != NICE_0_LOAD)) |
409 | delta = calc_delta_mine(delta, NICE_0_LOAD, &se->load); | |
a7be37ac PZ |
410 | |
411 | return delta; | |
412 | } | |
413 | ||
647e7cac IM |
414 | /* |
415 | * The idea is to set a period in which each task runs once. | |
416 | * | |
417 | * When there are too many tasks (sysctl_sched_nr_latency) we have to stretch | |
418 | * this period because otherwise the slices get too small. | |
419 | * | |
420 | * p = (nr <= nl) ? l : l*nr/nl | |
421 | */ | |
4d78e7b6 PZ |
422 | static u64 __sched_period(unsigned long nr_running) |
423 | { | |
424 | u64 period = sysctl_sched_latency; | |
b2be5e96 | 425 | unsigned long nr_latency = sched_nr_latency; |
4d78e7b6 PZ |
426 | |
427 | if (unlikely(nr_running > nr_latency)) { | |
4bf0b771 | 428 | period = sysctl_sched_min_granularity; |
4d78e7b6 | 429 | period *= nr_running; |
4d78e7b6 PZ |
430 | } |
431 | ||
432 | return period; | |
433 | } | |
434 | ||
647e7cac IM |
435 | /* |
436 | * We calculate the wall-time slice from the period by taking a part | |
437 | * proportional to the weight. | |
438 | * | |
f9c0b095 | 439 | * s = p*P[w/rw] |
647e7cac | 440 | */ |
6d0f0ebd | 441 | static u64 sched_slice(struct cfs_rq *cfs_rq, struct sched_entity *se) |
21805085 | 442 | { |
f9c0b095 PZ |
443 | unsigned long nr_running = cfs_rq->nr_running; |
444 | ||
445 | if (unlikely(!se->on_rq)) | |
446 | nr_running++; | |
447 | ||
448 | return calc_delta_weight(__sched_period(nr_running), se); | |
bf0f6f24 IM |
449 | } |
450 | ||
647e7cac | 451 | /* |
ac884dec | 452 | * We calculate the vruntime slice of a to be inserted task |
647e7cac | 453 | * |
f9c0b095 | 454 | * vs = s/w |
647e7cac | 455 | */ |
f9c0b095 | 456 | static u64 sched_vslice(struct cfs_rq *cfs_rq, struct sched_entity *se) |
67e9fb2a | 457 | { |
f9c0b095 | 458 | return calc_delta_fair(sched_slice(cfs_rq, se), se); |
a7be37ac PZ |
459 | } |
460 | ||
bf0f6f24 IM |
461 | /* |
462 | * Update the current task's runtime statistics. Skip current tasks that | |
463 | * are not in our scheduling class. | |
464 | */ | |
465 | static inline void | |
8ebc91d9 IM |
466 | __update_curr(struct cfs_rq *cfs_rq, struct sched_entity *curr, |
467 | unsigned long delta_exec) | |
bf0f6f24 | 468 | { |
bbdba7c0 | 469 | unsigned long delta_exec_weighted; |
bf0f6f24 | 470 | |
8179ca23 | 471 | schedstat_set(curr->exec_max, max((u64)delta_exec, curr->exec_max)); |
bf0f6f24 IM |
472 | |
473 | curr->sum_exec_runtime += delta_exec; | |
7a62eabc | 474 | schedstat_add(cfs_rq, exec_clock, delta_exec); |
a7be37ac | 475 | delta_exec_weighted = calc_delta_fair(delta_exec, curr); |
e9acbff6 | 476 | curr->vruntime += delta_exec_weighted; |
1af5f730 | 477 | update_min_vruntime(cfs_rq); |
bf0f6f24 IM |
478 | } |
479 | ||
b7cc0896 | 480 | static void update_curr(struct cfs_rq *cfs_rq) |
bf0f6f24 | 481 | { |
429d43bc | 482 | struct sched_entity *curr = cfs_rq->curr; |
8ebc91d9 | 483 | u64 now = rq_of(cfs_rq)->clock; |
bf0f6f24 IM |
484 | unsigned long delta_exec; |
485 | ||
486 | if (unlikely(!curr)) | |
487 | return; | |
488 | ||
489 | /* | |
490 | * Get the amount of time the current task was running | |
491 | * since the last time we changed load (this cannot | |
492 | * overflow on 32 bits): | |
493 | */ | |
8ebc91d9 | 494 | delta_exec = (unsigned long)(now - curr->exec_start); |
bf0f6f24 | 495 | |
8ebc91d9 IM |
496 | __update_curr(cfs_rq, curr, delta_exec); |
497 | curr->exec_start = now; | |
d842de87 SV |
498 | |
499 | if (entity_is_task(curr)) { | |
500 | struct task_struct *curtask = task_of(curr); | |
501 | ||
502 | cpuacct_charge(curtask, delta_exec); | |
f06febc9 | 503 | account_group_exec_runtime(curtask, delta_exec); |
d842de87 | 504 | } |
bf0f6f24 IM |
505 | } |
506 | ||
507 | static inline void | |
5870db5b | 508 | update_stats_wait_start(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 509 | { |
d281918d | 510 | schedstat_set(se->wait_start, rq_of(cfs_rq)->clock); |
bf0f6f24 IM |
511 | } |
512 | ||
bf0f6f24 IM |
513 | /* |
514 | * Task is being enqueued - update stats: | |
515 | */ | |
d2417e5a | 516 | static void update_stats_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 517 | { |
bf0f6f24 IM |
518 | /* |
519 | * Are we enqueueing a waiting task? (for current tasks | |
520 | * a dequeue/enqueue event is a NOP) | |
521 | */ | |
429d43bc | 522 | if (se != cfs_rq->curr) |
5870db5b | 523 | update_stats_wait_start(cfs_rq, se); |
bf0f6f24 IM |
524 | } |
525 | ||
bf0f6f24 | 526 | static void |
9ef0a961 | 527 | update_stats_wait_end(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 528 | { |
bbdba7c0 IM |
529 | schedstat_set(se->wait_max, max(se->wait_max, |
530 | rq_of(cfs_rq)->clock - se->wait_start)); | |
6d082592 AV |
531 | schedstat_set(se->wait_count, se->wait_count + 1); |
532 | schedstat_set(se->wait_sum, se->wait_sum + | |
533 | rq_of(cfs_rq)->clock - se->wait_start); | |
6cfb0d5d | 534 | schedstat_set(se->wait_start, 0); |
bf0f6f24 IM |
535 | } |
536 | ||
537 | static inline void | |
19b6a2e3 | 538 | update_stats_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 539 | { |
bf0f6f24 IM |
540 | /* |
541 | * Mark the end of the wait period if dequeueing a | |
542 | * waiting task: | |
543 | */ | |
429d43bc | 544 | if (se != cfs_rq->curr) |
9ef0a961 | 545 | update_stats_wait_end(cfs_rq, se); |
bf0f6f24 IM |
546 | } |
547 | ||
548 | /* | |
549 | * We are picking a new current task - update its stats: | |
550 | */ | |
551 | static inline void | |
79303e9e | 552 | update_stats_curr_start(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 IM |
553 | { |
554 | /* | |
555 | * We are starting a new run period: | |
556 | */ | |
d281918d | 557 | se->exec_start = rq_of(cfs_rq)->clock; |
bf0f6f24 IM |
558 | } |
559 | ||
bf0f6f24 IM |
560 | /************************************************** |
561 | * Scheduling class queueing methods: | |
562 | */ | |
563 | ||
c09595f6 PZ |
564 | #if defined CONFIG_SMP && defined CONFIG_FAIR_GROUP_SCHED |
565 | static void | |
566 | add_cfs_task_weight(struct cfs_rq *cfs_rq, unsigned long weight) | |
567 | { | |
568 | cfs_rq->task_weight += weight; | |
569 | } | |
570 | #else | |
571 | static inline void | |
572 | add_cfs_task_weight(struct cfs_rq *cfs_rq, unsigned long weight) | |
573 | { | |
574 | } | |
575 | #endif | |
576 | ||
30cfdcfc DA |
577 | static void |
578 | account_entity_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se) | |
579 | { | |
580 | update_load_add(&cfs_rq->load, se->load.weight); | |
c09595f6 PZ |
581 | if (!parent_entity(se)) |
582 | inc_cpu_load(rq_of(cfs_rq), se->load.weight); | |
b87f1724 | 583 | if (entity_is_task(se)) { |
c09595f6 | 584 | add_cfs_task_weight(cfs_rq, se->load.weight); |
b87f1724 BR |
585 | list_add(&se->group_node, &cfs_rq->tasks); |
586 | } | |
30cfdcfc DA |
587 | cfs_rq->nr_running++; |
588 | se->on_rq = 1; | |
589 | } | |
590 | ||
591 | static void | |
592 | account_entity_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se) | |
593 | { | |
594 | update_load_sub(&cfs_rq->load, se->load.weight); | |
c09595f6 PZ |
595 | if (!parent_entity(se)) |
596 | dec_cpu_load(rq_of(cfs_rq), se->load.weight); | |
b87f1724 | 597 | if (entity_is_task(se)) { |
c09595f6 | 598 | add_cfs_task_weight(cfs_rq, -se->load.weight); |
b87f1724 BR |
599 | list_del_init(&se->group_node); |
600 | } | |
30cfdcfc DA |
601 | cfs_rq->nr_running--; |
602 | se->on_rq = 0; | |
603 | } | |
604 | ||
2396af69 | 605 | static void enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 606 | { |
bf0f6f24 IM |
607 | #ifdef CONFIG_SCHEDSTATS |
608 | if (se->sleep_start) { | |
d281918d | 609 | u64 delta = rq_of(cfs_rq)->clock - se->sleep_start; |
9745512c | 610 | struct task_struct *tsk = task_of(se); |
bf0f6f24 IM |
611 | |
612 | if ((s64)delta < 0) | |
613 | delta = 0; | |
614 | ||
615 | if (unlikely(delta > se->sleep_max)) | |
616 | se->sleep_max = delta; | |
617 | ||
618 | se->sleep_start = 0; | |
619 | se->sum_sleep_runtime += delta; | |
9745512c AV |
620 | |
621 | account_scheduler_latency(tsk, delta >> 10, 1); | |
bf0f6f24 IM |
622 | } |
623 | if (se->block_start) { | |
d281918d | 624 | u64 delta = rq_of(cfs_rq)->clock - se->block_start; |
9745512c | 625 | struct task_struct *tsk = task_of(se); |
bf0f6f24 IM |
626 | |
627 | if ((s64)delta < 0) | |
628 | delta = 0; | |
629 | ||
630 | if (unlikely(delta > se->block_max)) | |
631 | se->block_max = delta; | |
632 | ||
633 | se->block_start = 0; | |
634 | se->sum_sleep_runtime += delta; | |
30084fbd IM |
635 | |
636 | /* | |
637 | * Blocking time is in units of nanosecs, so shift by 20 to | |
638 | * get a milliseconds-range estimation of the amount of | |
639 | * time that the task spent sleeping: | |
640 | */ | |
641 | if (unlikely(prof_on == SLEEP_PROFILING)) { | |
e22f5bbf | 642 | |
30084fbd IM |
643 | profile_hits(SLEEP_PROFILING, (void *)get_wchan(tsk), |
644 | delta >> 20); | |
645 | } | |
9745512c | 646 | account_scheduler_latency(tsk, delta >> 10, 0); |
bf0f6f24 IM |
647 | } |
648 | #endif | |
649 | } | |
650 | ||
ddc97297 PZ |
651 | static void check_spread(struct cfs_rq *cfs_rq, struct sched_entity *se) |
652 | { | |
653 | #ifdef CONFIG_SCHED_DEBUG | |
654 | s64 d = se->vruntime - cfs_rq->min_vruntime; | |
655 | ||
656 | if (d < 0) | |
657 | d = -d; | |
658 | ||
659 | if (d > 3*sysctl_sched_latency) | |
660 | schedstat_inc(cfs_rq, nr_spread_over); | |
661 | #endif | |
662 | } | |
663 | ||
aeb73b04 PZ |
664 | static void |
665 | place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial) | |
666 | { | |
1af5f730 | 667 | u64 vruntime = cfs_rq->min_vruntime; |
94dfb5e7 | 668 | |
2cb8600e PZ |
669 | /* |
670 | * The 'current' period is already promised to the current tasks, | |
671 | * however the extra weight of the new task will slow them down a | |
672 | * little, place the new task so that it fits in the slot that | |
673 | * stays open at the end. | |
674 | */ | |
94dfb5e7 | 675 | if (initial && sched_feat(START_DEBIT)) |
f9c0b095 | 676 | vruntime += sched_vslice(cfs_rq, se); |
aeb73b04 | 677 | |
8465e792 | 678 | if (!initial) { |
2cb8600e | 679 | /* sleeps upto a single latency don't count. */ |
a7be37ac PZ |
680 | if (sched_feat(NEW_FAIR_SLEEPERS)) { |
681 | unsigned long thresh = sysctl_sched_latency; | |
682 | ||
683 | /* | |
684 | * convert the sleeper threshold into virtual time | |
685 | */ | |
686 | if (sched_feat(NORMALIZED_SLEEPER)) | |
687 | thresh = calc_delta_fair(thresh, se); | |
688 | ||
689 | vruntime -= thresh; | |
690 | } | |
94359f05 | 691 | |
2cb8600e PZ |
692 | /* ensure we never gain time by being placed backwards. */ |
693 | vruntime = max_vruntime(se->vruntime, vruntime); | |
aeb73b04 PZ |
694 | } |
695 | ||
67e9fb2a | 696 | se->vruntime = vruntime; |
aeb73b04 PZ |
697 | } |
698 | ||
bf0f6f24 | 699 | static void |
83b699ed | 700 | enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int wakeup) |
bf0f6f24 IM |
701 | { |
702 | /* | |
a2a2d680 | 703 | * Update run-time statistics of the 'current'. |
bf0f6f24 | 704 | */ |
b7cc0896 | 705 | update_curr(cfs_rq); |
a992241d | 706 | account_entity_enqueue(cfs_rq, se); |
bf0f6f24 | 707 | |
e9acbff6 | 708 | if (wakeup) { |
aeb73b04 | 709 | place_entity(cfs_rq, se, 0); |
2396af69 | 710 | enqueue_sleeper(cfs_rq, se); |
e9acbff6 | 711 | } |
bf0f6f24 | 712 | |
d2417e5a | 713 | update_stats_enqueue(cfs_rq, se); |
ddc97297 | 714 | check_spread(cfs_rq, se); |
83b699ed SV |
715 | if (se != cfs_rq->curr) |
716 | __enqueue_entity(cfs_rq, se); | |
bf0f6f24 IM |
717 | } |
718 | ||
2002c695 PZ |
719 | static void clear_buddies(struct cfs_rq *cfs_rq, struct sched_entity *se) |
720 | { | |
721 | if (cfs_rq->last == se) | |
722 | cfs_rq->last = NULL; | |
723 | ||
724 | if (cfs_rq->next == se) | |
725 | cfs_rq->next = NULL; | |
726 | } | |
727 | ||
bf0f6f24 | 728 | static void |
525c2716 | 729 | dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int sleep) |
bf0f6f24 | 730 | { |
a2a2d680 DA |
731 | /* |
732 | * Update run-time statistics of the 'current'. | |
733 | */ | |
734 | update_curr(cfs_rq); | |
735 | ||
19b6a2e3 | 736 | update_stats_dequeue(cfs_rq, se); |
db36cc7d | 737 | if (sleep) { |
67e9fb2a | 738 | #ifdef CONFIG_SCHEDSTATS |
bf0f6f24 IM |
739 | if (entity_is_task(se)) { |
740 | struct task_struct *tsk = task_of(se); | |
741 | ||
742 | if (tsk->state & TASK_INTERRUPTIBLE) | |
d281918d | 743 | se->sleep_start = rq_of(cfs_rq)->clock; |
bf0f6f24 | 744 | if (tsk->state & TASK_UNINTERRUPTIBLE) |
d281918d | 745 | se->block_start = rq_of(cfs_rq)->clock; |
bf0f6f24 | 746 | } |
db36cc7d | 747 | #endif |
67e9fb2a PZ |
748 | } |
749 | ||
2002c695 | 750 | clear_buddies(cfs_rq, se); |
4793241b | 751 | |
83b699ed | 752 | if (se != cfs_rq->curr) |
30cfdcfc DA |
753 | __dequeue_entity(cfs_rq, se); |
754 | account_entity_dequeue(cfs_rq, se); | |
1af5f730 | 755 | update_min_vruntime(cfs_rq); |
bf0f6f24 IM |
756 | } |
757 | ||
758 | /* | |
759 | * Preempt the current task with a newly woken task if needed: | |
760 | */ | |
7c92e54f | 761 | static void |
2e09bf55 | 762 | check_preempt_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr) |
bf0f6f24 | 763 | { |
11697830 PZ |
764 | unsigned long ideal_runtime, delta_exec; |
765 | ||
6d0f0ebd | 766 | ideal_runtime = sched_slice(cfs_rq, curr); |
11697830 | 767 | delta_exec = curr->sum_exec_runtime - curr->prev_sum_exec_runtime; |
3e3e13f3 | 768 | if (delta_exec > ideal_runtime) |
bf0f6f24 IM |
769 | resched_task(rq_of(cfs_rq)->curr); |
770 | } | |
771 | ||
83b699ed | 772 | static void |
8494f412 | 773 | set_next_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 774 | { |
83b699ed SV |
775 | /* 'current' is not kept within the tree. */ |
776 | if (se->on_rq) { | |
777 | /* | |
778 | * Any task has to be enqueued before it get to execute on | |
779 | * a CPU. So account for the time it spent waiting on the | |
780 | * runqueue. | |
781 | */ | |
782 | update_stats_wait_end(cfs_rq, se); | |
783 | __dequeue_entity(cfs_rq, se); | |
784 | } | |
785 | ||
79303e9e | 786 | update_stats_curr_start(cfs_rq, se); |
429d43bc | 787 | cfs_rq->curr = se; |
eba1ed4b IM |
788 | #ifdef CONFIG_SCHEDSTATS |
789 | /* | |
790 | * Track our maximum slice length, if the CPU's load is at | |
791 | * least twice that of our own weight (i.e. dont track it | |
792 | * when there are only lesser-weight tasks around): | |
793 | */ | |
495eca49 | 794 | if (rq_of(cfs_rq)->load.weight >= 2*se->load.weight) { |
eba1ed4b IM |
795 | se->slice_max = max(se->slice_max, |
796 | se->sum_exec_runtime - se->prev_sum_exec_runtime); | |
797 | } | |
798 | #endif | |
4a55b450 | 799 | se->prev_sum_exec_runtime = se->sum_exec_runtime; |
bf0f6f24 IM |
800 | } |
801 | ||
3f3a4904 PZ |
802 | static int |
803 | wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se); | |
804 | ||
f4b6755f | 805 | static struct sched_entity *pick_next_entity(struct cfs_rq *cfs_rq) |
aa2ac252 | 806 | { |
f4b6755f PZ |
807 | struct sched_entity *se = __pick_next_entity(cfs_rq); |
808 | ||
4793241b PZ |
809 | if (cfs_rq->next && wakeup_preempt_entity(cfs_rq->next, se) < 1) |
810 | return cfs_rq->next; | |
aa2ac252 | 811 | |
4793241b PZ |
812 | if (cfs_rq->last && wakeup_preempt_entity(cfs_rq->last, se) < 1) |
813 | return cfs_rq->last; | |
814 | ||
815 | return se; | |
aa2ac252 PZ |
816 | } |
817 | ||
ab6cde26 | 818 | static void put_prev_entity(struct cfs_rq *cfs_rq, struct sched_entity *prev) |
bf0f6f24 IM |
819 | { |
820 | /* | |
821 | * If still on the runqueue then deactivate_task() | |
822 | * was not called and update_curr() has to be done: | |
823 | */ | |
824 | if (prev->on_rq) | |
b7cc0896 | 825 | update_curr(cfs_rq); |
bf0f6f24 | 826 | |
ddc97297 | 827 | check_spread(cfs_rq, prev); |
30cfdcfc | 828 | if (prev->on_rq) { |
5870db5b | 829 | update_stats_wait_start(cfs_rq, prev); |
30cfdcfc DA |
830 | /* Put 'current' back into the tree. */ |
831 | __enqueue_entity(cfs_rq, prev); | |
832 | } | |
429d43bc | 833 | cfs_rq->curr = NULL; |
bf0f6f24 IM |
834 | } |
835 | ||
8f4d37ec PZ |
836 | static void |
837 | entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr, int queued) | |
bf0f6f24 | 838 | { |
bf0f6f24 | 839 | /* |
30cfdcfc | 840 | * Update run-time statistics of the 'current'. |
bf0f6f24 | 841 | */ |
30cfdcfc | 842 | update_curr(cfs_rq); |
bf0f6f24 | 843 | |
8f4d37ec PZ |
844 | #ifdef CONFIG_SCHED_HRTICK |
845 | /* | |
846 | * queued ticks are scheduled to match the slice, so don't bother | |
847 | * validating it and just reschedule. | |
848 | */ | |
983ed7a6 HH |
849 | if (queued) { |
850 | resched_task(rq_of(cfs_rq)->curr); | |
851 | return; | |
852 | } | |
8f4d37ec PZ |
853 | /* |
854 | * don't let the period tick interfere with the hrtick preemption | |
855 | */ | |
856 | if (!sched_feat(DOUBLE_TICK) && | |
857 | hrtimer_active(&rq_of(cfs_rq)->hrtick_timer)) | |
858 | return; | |
859 | #endif | |
860 | ||
ce6c1311 | 861 | if (cfs_rq->nr_running > 1 || !sched_feat(WAKEUP_PREEMPT)) |
2e09bf55 | 862 | check_preempt_tick(cfs_rq, curr); |
bf0f6f24 IM |
863 | } |
864 | ||
865 | /************************************************** | |
866 | * CFS operations on tasks: | |
867 | */ | |
868 | ||
8f4d37ec PZ |
869 | #ifdef CONFIG_SCHED_HRTICK |
870 | static void hrtick_start_fair(struct rq *rq, struct task_struct *p) | |
871 | { | |
8f4d37ec PZ |
872 | struct sched_entity *se = &p->se; |
873 | struct cfs_rq *cfs_rq = cfs_rq_of(se); | |
874 | ||
875 | WARN_ON(task_rq(p) != rq); | |
876 | ||
877 | if (hrtick_enabled(rq) && cfs_rq->nr_running > 1) { | |
878 | u64 slice = sched_slice(cfs_rq, se); | |
879 | u64 ran = se->sum_exec_runtime - se->prev_sum_exec_runtime; | |
880 | s64 delta = slice - ran; | |
881 | ||
882 | if (delta < 0) { | |
883 | if (rq->curr == p) | |
884 | resched_task(p); | |
885 | return; | |
886 | } | |
887 | ||
888 | /* | |
889 | * Don't schedule slices shorter than 10000ns, that just | |
890 | * doesn't make sense. Rely on vruntime for fairness. | |
891 | */ | |
31656519 | 892 | if (rq->curr != p) |
157124c1 | 893 | delta = max_t(s64, 10000LL, delta); |
8f4d37ec | 894 | |
31656519 | 895 | hrtick_start(rq, delta); |
8f4d37ec PZ |
896 | } |
897 | } | |
a4c2f00f PZ |
898 | |
899 | /* | |
900 | * called from enqueue/dequeue and updates the hrtick when the | |
901 | * current task is from our class and nr_running is low enough | |
902 | * to matter. | |
903 | */ | |
904 | static void hrtick_update(struct rq *rq) | |
905 | { | |
906 | struct task_struct *curr = rq->curr; | |
907 | ||
908 | if (curr->sched_class != &fair_sched_class) | |
909 | return; | |
910 | ||
911 | if (cfs_rq_of(&curr->se)->nr_running < sched_nr_latency) | |
912 | hrtick_start_fair(rq, curr); | |
913 | } | |
55e12e5e | 914 | #else /* !CONFIG_SCHED_HRTICK */ |
8f4d37ec PZ |
915 | static inline void |
916 | hrtick_start_fair(struct rq *rq, struct task_struct *p) | |
917 | { | |
918 | } | |
a4c2f00f PZ |
919 | |
920 | static inline void hrtick_update(struct rq *rq) | |
921 | { | |
922 | } | |
8f4d37ec PZ |
923 | #endif |
924 | ||
bf0f6f24 IM |
925 | /* |
926 | * The enqueue_task method is called before nr_running is | |
927 | * increased. Here we update the fair scheduling stats and | |
928 | * then put the task into the rbtree: | |
929 | */ | |
fd390f6a | 930 | static void enqueue_task_fair(struct rq *rq, struct task_struct *p, int wakeup) |
bf0f6f24 IM |
931 | { |
932 | struct cfs_rq *cfs_rq; | |
62fb1851 | 933 | struct sched_entity *se = &p->se; |
bf0f6f24 IM |
934 | |
935 | for_each_sched_entity(se) { | |
62fb1851 | 936 | if (se->on_rq) |
bf0f6f24 IM |
937 | break; |
938 | cfs_rq = cfs_rq_of(se); | |
83b699ed | 939 | enqueue_entity(cfs_rq, se, wakeup); |
b9fa3df3 | 940 | wakeup = 1; |
bf0f6f24 | 941 | } |
8f4d37ec | 942 | |
a4c2f00f | 943 | hrtick_update(rq); |
bf0f6f24 IM |
944 | } |
945 | ||
946 | /* | |
947 | * The dequeue_task method is called before nr_running is | |
948 | * decreased. We remove the task from the rbtree and | |
949 | * update the fair scheduling stats: | |
950 | */ | |
f02231e5 | 951 | static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int sleep) |
bf0f6f24 IM |
952 | { |
953 | struct cfs_rq *cfs_rq; | |
62fb1851 | 954 | struct sched_entity *se = &p->se; |
bf0f6f24 IM |
955 | |
956 | for_each_sched_entity(se) { | |
957 | cfs_rq = cfs_rq_of(se); | |
525c2716 | 958 | dequeue_entity(cfs_rq, se, sleep); |
bf0f6f24 | 959 | /* Don't dequeue parent if it has other entities besides us */ |
62fb1851 | 960 | if (cfs_rq->load.weight) |
bf0f6f24 | 961 | break; |
b9fa3df3 | 962 | sleep = 1; |
bf0f6f24 | 963 | } |
8f4d37ec | 964 | |
a4c2f00f | 965 | hrtick_update(rq); |
bf0f6f24 IM |
966 | } |
967 | ||
968 | /* | |
1799e35d IM |
969 | * sched_yield() support is very simple - we dequeue and enqueue. |
970 | * | |
971 | * If compat_yield is turned on then we requeue to the end of the tree. | |
bf0f6f24 | 972 | */ |
4530d7ab | 973 | static void yield_task_fair(struct rq *rq) |
bf0f6f24 | 974 | { |
db292ca3 IM |
975 | struct task_struct *curr = rq->curr; |
976 | struct cfs_rq *cfs_rq = task_cfs_rq(curr); | |
977 | struct sched_entity *rightmost, *se = &curr->se; | |
bf0f6f24 IM |
978 | |
979 | /* | |
1799e35d IM |
980 | * Are we the only task in the tree? |
981 | */ | |
982 | if (unlikely(cfs_rq->nr_running == 1)) | |
983 | return; | |
984 | ||
2002c695 PZ |
985 | clear_buddies(cfs_rq, se); |
986 | ||
db292ca3 | 987 | if (likely(!sysctl_sched_compat_yield) && curr->policy != SCHED_BATCH) { |
3e51f33f | 988 | update_rq_clock(rq); |
1799e35d | 989 | /* |
a2a2d680 | 990 | * Update run-time statistics of the 'current'. |
1799e35d | 991 | */ |
2b1e315d | 992 | update_curr(cfs_rq); |
1799e35d IM |
993 | |
994 | return; | |
995 | } | |
996 | /* | |
997 | * Find the rightmost entry in the rbtree: | |
bf0f6f24 | 998 | */ |
2b1e315d | 999 | rightmost = __pick_last_entity(cfs_rq); |
1799e35d IM |
1000 | /* |
1001 | * Already in the rightmost position? | |
1002 | */ | |
79b3feff | 1003 | if (unlikely(!rightmost || rightmost->vruntime < se->vruntime)) |
1799e35d IM |
1004 | return; |
1005 | ||
1006 | /* | |
1007 | * Minimally necessary key value to be last in the tree: | |
2b1e315d DA |
1008 | * Upon rescheduling, sched_class::put_prev_task() will place |
1009 | * 'current' within the tree based on its new key value. | |
1799e35d | 1010 | */ |
30cfdcfc | 1011 | se->vruntime = rightmost->vruntime + 1; |
bf0f6f24 IM |
1012 | } |
1013 | ||
e7693a36 GH |
1014 | /* |
1015 | * wake_idle() will wake a task on an idle cpu if task->cpu is | |
1016 | * not idle and an idle cpu is available. The span of cpus to | |
1017 | * search starts with cpus closest then further out as needed, | |
1018 | * so we always favor a closer, idle cpu. | |
e761b772 MK |
1019 | * Domains may include CPUs that are not usable for migration, |
1020 | * hence we need to mask them out (cpu_active_map) | |
e7693a36 GH |
1021 | * |
1022 | * Returns the CPU we should wake onto. | |
1023 | */ | |
1024 | #if defined(ARCH_HAS_SCHED_WAKE_IDLE) | |
1025 | static int wake_idle(int cpu, struct task_struct *p) | |
1026 | { | |
1027 | cpumask_t tmp; | |
1028 | struct sched_domain *sd; | |
1029 | int i; | |
1030 | ||
1031 | /* | |
1032 | * If it is idle, then it is the best cpu to run this task. | |
1033 | * | |
1034 | * This cpu is also the best, if it has more than one task already. | |
1035 | * Siblings must be also busy(in most cases) as they didn't already | |
1036 | * pickup the extra load from this cpu and hence we need not check | |
1037 | * sibling runqueue info. This will avoid the checks and cache miss | |
1038 | * penalities associated with that. | |
1039 | */ | |
104f6454 | 1040 | if (idle_cpu(cpu) || cpu_rq(cpu)->cfs.nr_running > 1) |
e7693a36 GH |
1041 | return cpu; |
1042 | ||
1043 | for_each_domain(cpu, sd) { | |
1d3504fc HS |
1044 | if ((sd->flags & SD_WAKE_IDLE) |
1045 | || ((sd->flags & SD_WAKE_IDLE_FAR) | |
1046 | && !task_hot(p, task_rq(p)->clock, sd))) { | |
e7693a36 | 1047 | cpus_and(tmp, sd->span, p->cpus_allowed); |
e761b772 | 1048 | cpus_and(tmp, tmp, cpu_active_map); |
363ab6f1 | 1049 | for_each_cpu_mask_nr(i, tmp) { |
e7693a36 GH |
1050 | if (idle_cpu(i)) { |
1051 | if (i != task_cpu(p)) { | |
1052 | schedstat_inc(p, | |
1053 | se.nr_wakeups_idle); | |
1054 | } | |
1055 | return i; | |
1056 | } | |
1057 | } | |
1058 | } else { | |
1059 | break; | |
1060 | } | |
1061 | } | |
1062 | return cpu; | |
1063 | } | |
55e12e5e | 1064 | #else /* !ARCH_HAS_SCHED_WAKE_IDLE*/ |
e7693a36 GH |
1065 | static inline int wake_idle(int cpu, struct task_struct *p) |
1066 | { | |
1067 | return cpu; | |
1068 | } | |
1069 | #endif | |
1070 | ||
1071 | #ifdef CONFIG_SMP | |
098fb9db | 1072 | |
bb3469ac | 1073 | #ifdef CONFIG_FAIR_GROUP_SCHED |
f5bfb7d9 PZ |
1074 | /* |
1075 | * effective_load() calculates the load change as seen from the root_task_group | |
1076 | * | |
1077 | * Adding load to a group doesn't make a group heavier, but can cause movement | |
1078 | * of group shares between cpus. Assuming the shares were perfectly aligned one | |
1079 | * can calculate the shift in shares. | |
1080 | * | |
1081 | * The problem is that perfectly aligning the shares is rather expensive, hence | |
1082 | * we try to avoid doing that too often - see update_shares(), which ratelimits | |
1083 | * this change. | |
1084 | * | |
1085 | * We compensate this by not only taking the current delta into account, but | |
1086 | * also considering the delta between when the shares were last adjusted and | |
1087 | * now. | |
1088 | * | |
1089 | * We still saw a performance dip, some tracing learned us that between | |
1090 | * cgroup:/ and cgroup:/foo balancing the number of affine wakeups increased | |
1091 | * significantly. Therefore try to bias the error in direction of failing | |
1092 | * the affine wakeup. | |
1093 | * | |
1094 | */ | |
f1d239f7 PZ |
1095 | static long effective_load(struct task_group *tg, int cpu, |
1096 | long wl, long wg) | |
bb3469ac | 1097 | { |
4be9daaa | 1098 | struct sched_entity *se = tg->se[cpu]; |
f1d239f7 PZ |
1099 | |
1100 | if (!tg->parent) | |
1101 | return wl; | |
1102 | ||
f5bfb7d9 PZ |
1103 | /* |
1104 | * By not taking the decrease of shares on the other cpu into | |
1105 | * account our error leans towards reducing the affine wakeups. | |
1106 | */ | |
1107 | if (!wl && sched_feat(ASYM_EFF_LOAD)) | |
1108 | return wl; | |
1109 | ||
4be9daaa | 1110 | for_each_sched_entity(se) { |
cb5ef42a | 1111 | long S, rw, s, a, b; |
940959e9 PZ |
1112 | long more_w; |
1113 | ||
1114 | /* | |
1115 | * Instead of using this increment, also add the difference | |
1116 | * between when the shares were last updated and now. | |
1117 | */ | |
1118 | more_w = se->my_q->load.weight - se->my_q->rq_weight; | |
1119 | wl += more_w; | |
1120 | wg += more_w; | |
4be9daaa PZ |
1121 | |
1122 | S = se->my_q->tg->shares; | |
1123 | s = se->my_q->shares; | |
f1d239f7 | 1124 | rw = se->my_q->rq_weight; |
bb3469ac | 1125 | |
cb5ef42a PZ |
1126 | a = S*(rw + wl); |
1127 | b = S*rw + s*wg; | |
4be9daaa | 1128 | |
940959e9 PZ |
1129 | wl = s*(a-b); |
1130 | ||
1131 | if (likely(b)) | |
1132 | wl /= b; | |
1133 | ||
83378269 PZ |
1134 | /* |
1135 | * Assume the group is already running and will | |
1136 | * thus already be accounted for in the weight. | |
1137 | * | |
1138 | * That is, moving shares between CPUs, does not | |
1139 | * alter the group weight. | |
1140 | */ | |
4be9daaa | 1141 | wg = 0; |
4be9daaa | 1142 | } |
bb3469ac | 1143 | |
4be9daaa | 1144 | return wl; |
bb3469ac | 1145 | } |
4be9daaa | 1146 | |
bb3469ac | 1147 | #else |
4be9daaa | 1148 | |
83378269 PZ |
1149 | static inline unsigned long effective_load(struct task_group *tg, int cpu, |
1150 | unsigned long wl, unsigned long wg) | |
4be9daaa | 1151 | { |
83378269 | 1152 | return wl; |
bb3469ac | 1153 | } |
4be9daaa | 1154 | |
bb3469ac PZ |
1155 | #endif |
1156 | ||
098fb9db | 1157 | static int |
64b9e029 | 1158 | wake_affine(struct sched_domain *this_sd, struct rq *this_rq, |
4ae7d5ce IM |
1159 | struct task_struct *p, int prev_cpu, int this_cpu, int sync, |
1160 | int idx, unsigned long load, unsigned long this_load, | |
098fb9db IM |
1161 | unsigned int imbalance) |
1162 | { | |
4ae7d5ce | 1163 | struct task_struct *curr = this_rq->curr; |
83378269 | 1164 | struct task_group *tg; |
098fb9db IM |
1165 | unsigned long tl = this_load; |
1166 | unsigned long tl_per_task; | |
83378269 | 1167 | unsigned long weight; |
b3137bc8 | 1168 | int balanced; |
098fb9db | 1169 | |
b3137bc8 | 1170 | if (!(this_sd->flags & SD_WAKE_AFFINE) || !sched_feat(AFFINE_WAKEUPS)) |
098fb9db IM |
1171 | return 0; |
1172 | ||
0d13033b MG |
1173 | if (sync && (curr->se.avg_overlap > sysctl_sched_migration_cost || |
1174 | p->se.avg_overlap > sysctl_sched_migration_cost)) | |
1175 | sync = 0; | |
2fb7635c | 1176 | |
b3137bc8 MG |
1177 | /* |
1178 | * If sync wakeup then subtract the (maximum possible) | |
1179 | * effect of the currently running task from the load | |
1180 | * of the current CPU: | |
1181 | */ | |
83378269 PZ |
1182 | if (sync) { |
1183 | tg = task_group(current); | |
1184 | weight = current->se.load.weight; | |
1185 | ||
1186 | tl += effective_load(tg, this_cpu, -weight, -weight); | |
1187 | load += effective_load(tg, prev_cpu, 0, -weight); | |
1188 | } | |
b3137bc8 | 1189 | |
83378269 PZ |
1190 | tg = task_group(p); |
1191 | weight = p->se.load.weight; | |
b3137bc8 | 1192 | |
83378269 PZ |
1193 | balanced = 100*(tl + effective_load(tg, this_cpu, weight, weight)) <= |
1194 | imbalance*(load + effective_load(tg, prev_cpu, 0, weight)); | |
b3137bc8 | 1195 | |
098fb9db | 1196 | /* |
4ae7d5ce IM |
1197 | * If the currently running task will sleep within |
1198 | * a reasonable amount of time then attract this newly | |
1199 | * woken task: | |
098fb9db | 1200 | */ |
2fb7635c PZ |
1201 | if (sync && balanced) |
1202 | return 1; | |
098fb9db IM |
1203 | |
1204 | schedstat_inc(p, se.nr_wakeups_affine_attempts); | |
1205 | tl_per_task = cpu_avg_load_per_task(this_cpu); | |
1206 | ||
64b9e029 AA |
1207 | if (balanced || (tl <= load && tl + target_load(prev_cpu, idx) <= |
1208 | tl_per_task)) { | |
098fb9db IM |
1209 | /* |
1210 | * This domain has SD_WAKE_AFFINE and | |
1211 | * p is cache cold in this domain, and | |
1212 | * there is no bad imbalance. | |
1213 | */ | |
1214 | schedstat_inc(this_sd, ttwu_move_affine); | |
1215 | schedstat_inc(p, se.nr_wakeups_affine); | |
1216 | ||
1217 | return 1; | |
1218 | } | |
1219 | return 0; | |
1220 | } | |
1221 | ||
e7693a36 GH |
1222 | static int select_task_rq_fair(struct task_struct *p, int sync) |
1223 | { | |
e7693a36 | 1224 | struct sched_domain *sd, *this_sd = NULL; |
ac192d39 | 1225 | int prev_cpu, this_cpu, new_cpu; |
098fb9db | 1226 | unsigned long load, this_load; |
64b9e029 | 1227 | struct rq *this_rq; |
098fb9db | 1228 | unsigned int imbalance; |
098fb9db | 1229 | int idx; |
e7693a36 | 1230 | |
ac192d39 | 1231 | prev_cpu = task_cpu(p); |
ac192d39 | 1232 | this_cpu = smp_processor_id(); |
4ae7d5ce | 1233 | this_rq = cpu_rq(this_cpu); |
ac192d39 | 1234 | new_cpu = prev_cpu; |
e7693a36 | 1235 | |
64b9e029 AA |
1236 | if (prev_cpu == this_cpu) |
1237 | goto out; | |
ac192d39 IM |
1238 | /* |
1239 | * 'this_sd' is the first domain that both | |
1240 | * this_cpu and prev_cpu are present in: | |
1241 | */ | |
e7693a36 | 1242 | for_each_domain(this_cpu, sd) { |
ac192d39 | 1243 | if (cpu_isset(prev_cpu, sd->span)) { |
e7693a36 GH |
1244 | this_sd = sd; |
1245 | break; | |
1246 | } | |
1247 | } | |
1248 | ||
1249 | if (unlikely(!cpu_isset(this_cpu, p->cpus_allowed))) | |
f4827386 | 1250 | goto out; |
e7693a36 GH |
1251 | |
1252 | /* | |
1253 | * Check for affine wakeup and passive balancing possibilities. | |
1254 | */ | |
098fb9db | 1255 | if (!this_sd) |
f4827386 | 1256 | goto out; |
e7693a36 | 1257 | |
098fb9db IM |
1258 | idx = this_sd->wake_idx; |
1259 | ||
1260 | imbalance = 100 + (this_sd->imbalance_pct - 100) / 2; | |
1261 | ||
ac192d39 | 1262 | load = source_load(prev_cpu, idx); |
098fb9db IM |
1263 | this_load = target_load(this_cpu, idx); |
1264 | ||
64b9e029 | 1265 | if (wake_affine(this_sd, this_rq, p, prev_cpu, this_cpu, sync, idx, |
4ae7d5ce IM |
1266 | load, this_load, imbalance)) |
1267 | return this_cpu; | |
1268 | ||
098fb9db IM |
1269 | /* |
1270 | * Start passive balancing when half the imbalance_pct | |
1271 | * limit is reached. | |
1272 | */ | |
1273 | if (this_sd->flags & SD_WAKE_BALANCE) { | |
1274 | if (imbalance*this_load <= 100*load) { | |
1275 | schedstat_inc(this_sd, ttwu_move_balance); | |
1276 | schedstat_inc(p, se.nr_wakeups_passive); | |
4ae7d5ce | 1277 | return this_cpu; |
e7693a36 GH |
1278 | } |
1279 | } | |
1280 | ||
f4827386 | 1281 | out: |
e7693a36 GH |
1282 | return wake_idle(new_cpu, p); |
1283 | } | |
1284 | #endif /* CONFIG_SMP */ | |
1285 | ||
0bbd3336 PZ |
1286 | static unsigned long wakeup_gran(struct sched_entity *se) |
1287 | { | |
1288 | unsigned long gran = sysctl_sched_wakeup_granularity; | |
1289 | ||
1290 | /* | |
a7be37ac PZ |
1291 | * More easily preempt - nice tasks, while not making it harder for |
1292 | * + nice tasks. | |
0bbd3336 | 1293 | */ |
464b7527 PZ |
1294 | if (!sched_feat(ASYM_GRAN) || se->load.weight > NICE_0_LOAD) |
1295 | gran = calc_delta_fair(sysctl_sched_wakeup_granularity, se); | |
0bbd3336 PZ |
1296 | |
1297 | return gran; | |
1298 | } | |
1299 | ||
464b7527 PZ |
1300 | /* |
1301 | * Should 'se' preempt 'curr'. | |
1302 | * | |
1303 | * |s1 | |
1304 | * |s2 | |
1305 | * |s3 | |
1306 | * g | |
1307 | * |<--->|c | |
1308 | * | |
1309 | * w(c, s1) = -1 | |
1310 | * w(c, s2) = 0 | |
1311 | * w(c, s3) = 1 | |
1312 | * | |
1313 | */ | |
1314 | static int | |
1315 | wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se) | |
1316 | { | |
1317 | s64 gran, vdiff = curr->vruntime - se->vruntime; | |
1318 | ||
1319 | if (vdiff <= 0) | |
1320 | return -1; | |
1321 | ||
1322 | gran = wakeup_gran(curr); | |
1323 | if (vdiff > gran) | |
1324 | return 1; | |
1325 | ||
1326 | return 0; | |
1327 | } | |
1328 | ||
02479099 PZ |
1329 | static void set_last_buddy(struct sched_entity *se) |
1330 | { | |
1331 | for_each_sched_entity(se) | |
1332 | cfs_rq_of(se)->last = se; | |
1333 | } | |
1334 | ||
1335 | static void set_next_buddy(struct sched_entity *se) | |
1336 | { | |
1337 | for_each_sched_entity(se) | |
1338 | cfs_rq_of(se)->next = se; | |
1339 | } | |
1340 | ||
bf0f6f24 IM |
1341 | /* |
1342 | * Preempt the current task with a newly woken task if needed: | |
1343 | */ | |
15afe09b | 1344 | static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int sync) |
bf0f6f24 IM |
1345 | { |
1346 | struct task_struct *curr = rq->curr; | |
8651a86c | 1347 | struct sched_entity *se = &curr->se, *pse = &p->se; |
bf0f6f24 IM |
1348 | |
1349 | if (unlikely(rt_prio(p->prio))) { | |
4793241b PZ |
1350 | struct cfs_rq *cfs_rq = task_cfs_rq(curr); |
1351 | ||
a8e504d2 | 1352 | update_rq_clock(rq); |
b7cc0896 | 1353 | update_curr(cfs_rq); |
bf0f6f24 IM |
1354 | resched_task(curr); |
1355 | return; | |
1356 | } | |
aa2ac252 | 1357 | |
d95f98d0 PZ |
1358 | if (unlikely(p->sched_class != &fair_sched_class)) |
1359 | return; | |
1360 | ||
4ae7d5ce IM |
1361 | if (unlikely(se == pse)) |
1362 | return; | |
1363 | ||
4793241b PZ |
1364 | /* |
1365 | * Only set the backward buddy when the current task is still on the | |
1366 | * rq. This can happen when a wakeup gets interleaved with schedule on | |
1367 | * the ->pre_schedule() or idle_balance() point, either of which can | |
1368 | * drop the rq lock. | |
1369 | * | |
1370 | * Also, during early boot the idle thread is in the fair class, for | |
1371 | * obvious reasons its a bad idea to schedule back to the idle thread. | |
1372 | */ | |
1373 | if (sched_feat(LAST_BUDDY) && likely(se->on_rq && curr != rq->idle)) | |
02479099 PZ |
1374 | set_last_buddy(se); |
1375 | set_next_buddy(pse); | |
57fdc26d | 1376 | |
aec0a514 BR |
1377 | /* |
1378 | * We can come here with TIF_NEED_RESCHED already set from new task | |
1379 | * wake up path. | |
1380 | */ | |
1381 | if (test_tsk_need_resched(curr)) | |
1382 | return; | |
1383 | ||
91c234b4 IM |
1384 | /* |
1385 | * Batch tasks do not preempt (their preemption is driven by | |
1386 | * the tick): | |
1387 | */ | |
1388 | if (unlikely(p->policy == SCHED_BATCH)) | |
1389 | return; | |
bf0f6f24 | 1390 | |
77d9cc44 IM |
1391 | if (!sched_feat(WAKEUP_PREEMPT)) |
1392 | return; | |
8651a86c | 1393 | |
2fb7635c PZ |
1394 | if (sched_feat(WAKEUP_OVERLAP) && (sync || |
1395 | (se->avg_overlap < sysctl_sched_migration_cost && | |
1396 | pse->avg_overlap < sysctl_sched_migration_cost))) { | |
15afe09b PZ |
1397 | resched_task(curr); |
1398 | return; | |
1399 | } | |
1400 | ||
464b7527 PZ |
1401 | find_matching_se(&se, &pse); |
1402 | ||
1403 | while (se) { | |
1404 | BUG_ON(!pse); | |
1405 | ||
1406 | if (wakeup_preempt_entity(se, pse) == 1) { | |
1407 | resched_task(curr); | |
1408 | break; | |
1409 | } | |
1410 | ||
1411 | se = parent_entity(se); | |
1412 | pse = parent_entity(pse); | |
1413 | } | |
bf0f6f24 IM |
1414 | } |
1415 | ||
fb8d4724 | 1416 | static struct task_struct *pick_next_task_fair(struct rq *rq) |
bf0f6f24 | 1417 | { |
8f4d37ec | 1418 | struct task_struct *p; |
bf0f6f24 IM |
1419 | struct cfs_rq *cfs_rq = &rq->cfs; |
1420 | struct sched_entity *se; | |
1421 | ||
1422 | if (unlikely(!cfs_rq->nr_running)) | |
1423 | return NULL; | |
1424 | ||
1425 | do { | |
9948f4b2 | 1426 | se = pick_next_entity(cfs_rq); |
f4b6755f | 1427 | set_next_entity(cfs_rq, se); |
bf0f6f24 IM |
1428 | cfs_rq = group_cfs_rq(se); |
1429 | } while (cfs_rq); | |
1430 | ||
8f4d37ec PZ |
1431 | p = task_of(se); |
1432 | hrtick_start_fair(rq, p); | |
1433 | ||
1434 | return p; | |
bf0f6f24 IM |
1435 | } |
1436 | ||
1437 | /* | |
1438 | * Account for a descheduled task: | |
1439 | */ | |
31ee529c | 1440 | static void put_prev_task_fair(struct rq *rq, struct task_struct *prev) |
bf0f6f24 IM |
1441 | { |
1442 | struct sched_entity *se = &prev->se; | |
1443 | struct cfs_rq *cfs_rq; | |
1444 | ||
1445 | for_each_sched_entity(se) { | |
1446 | cfs_rq = cfs_rq_of(se); | |
ab6cde26 | 1447 | put_prev_entity(cfs_rq, se); |
bf0f6f24 IM |
1448 | } |
1449 | } | |
1450 | ||
681f3e68 | 1451 | #ifdef CONFIG_SMP |
bf0f6f24 IM |
1452 | /************************************************** |
1453 | * Fair scheduling class load-balancing methods: | |
1454 | */ | |
1455 | ||
1456 | /* | |
1457 | * Load-balancing iterator. Note: while the runqueue stays locked | |
1458 | * during the whole iteration, the current task might be | |
1459 | * dequeued so the iterator has to be dequeue-safe. Here we | |
1460 | * achieve that by always pre-iterating before returning | |
1461 | * the current task: | |
1462 | */ | |
a9957449 | 1463 | static struct task_struct * |
4a55bd5e | 1464 | __load_balance_iterator(struct cfs_rq *cfs_rq, struct list_head *next) |
bf0f6f24 | 1465 | { |
354d60c2 DG |
1466 | struct task_struct *p = NULL; |
1467 | struct sched_entity *se; | |
bf0f6f24 | 1468 | |
77ae6513 MG |
1469 | if (next == &cfs_rq->tasks) |
1470 | return NULL; | |
1471 | ||
b87f1724 BR |
1472 | se = list_entry(next, struct sched_entity, group_node); |
1473 | p = task_of(se); | |
1474 | cfs_rq->balance_iterator = next->next; | |
77ae6513 | 1475 | |
bf0f6f24 IM |
1476 | return p; |
1477 | } | |
1478 | ||
1479 | static struct task_struct *load_balance_start_fair(void *arg) | |
1480 | { | |
1481 | struct cfs_rq *cfs_rq = arg; | |
1482 | ||
4a55bd5e | 1483 | return __load_balance_iterator(cfs_rq, cfs_rq->tasks.next); |
bf0f6f24 IM |
1484 | } |
1485 | ||
1486 | static struct task_struct *load_balance_next_fair(void *arg) | |
1487 | { | |
1488 | struct cfs_rq *cfs_rq = arg; | |
1489 | ||
4a55bd5e | 1490 | return __load_balance_iterator(cfs_rq, cfs_rq->balance_iterator); |
bf0f6f24 IM |
1491 | } |
1492 | ||
c09595f6 PZ |
1493 | static unsigned long |
1494 | __load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
1495 | unsigned long max_load_move, struct sched_domain *sd, | |
1496 | enum cpu_idle_type idle, int *all_pinned, int *this_best_prio, | |
1497 | struct cfs_rq *cfs_rq) | |
62fb1851 | 1498 | { |
c09595f6 | 1499 | struct rq_iterator cfs_rq_iterator; |
62fb1851 | 1500 | |
c09595f6 PZ |
1501 | cfs_rq_iterator.start = load_balance_start_fair; |
1502 | cfs_rq_iterator.next = load_balance_next_fair; | |
1503 | cfs_rq_iterator.arg = cfs_rq; | |
62fb1851 | 1504 | |
c09595f6 PZ |
1505 | return balance_tasks(this_rq, this_cpu, busiest, |
1506 | max_load_move, sd, idle, all_pinned, | |
1507 | this_best_prio, &cfs_rq_iterator); | |
62fb1851 | 1508 | } |
62fb1851 | 1509 | |
c09595f6 | 1510 | #ifdef CONFIG_FAIR_GROUP_SCHED |
43010659 | 1511 | static unsigned long |
bf0f6f24 | 1512 | load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest, |
e1d1484f | 1513 | unsigned long max_load_move, |
a4ac01c3 PW |
1514 | struct sched_domain *sd, enum cpu_idle_type idle, |
1515 | int *all_pinned, int *this_best_prio) | |
bf0f6f24 | 1516 | { |
bf0f6f24 | 1517 | long rem_load_move = max_load_move; |
c09595f6 PZ |
1518 | int busiest_cpu = cpu_of(busiest); |
1519 | struct task_group *tg; | |
18d95a28 | 1520 | |
c09595f6 | 1521 | rcu_read_lock(); |
c8cba857 | 1522 | update_h_load(busiest_cpu); |
18d95a28 | 1523 | |
caea8a03 | 1524 | list_for_each_entry_rcu(tg, &task_groups, list) { |
c8cba857 | 1525 | struct cfs_rq *busiest_cfs_rq = tg->cfs_rq[busiest_cpu]; |
42a3ac7d PZ |
1526 | unsigned long busiest_h_load = busiest_cfs_rq->h_load; |
1527 | unsigned long busiest_weight = busiest_cfs_rq->load.weight; | |
243e0e7b | 1528 | u64 rem_load, moved_load; |
18d95a28 | 1529 | |
c09595f6 PZ |
1530 | /* |
1531 | * empty group | |
1532 | */ | |
c8cba857 | 1533 | if (!busiest_cfs_rq->task_weight) |
bf0f6f24 IM |
1534 | continue; |
1535 | ||
243e0e7b SV |
1536 | rem_load = (u64)rem_load_move * busiest_weight; |
1537 | rem_load = div_u64(rem_load, busiest_h_load + 1); | |
bf0f6f24 | 1538 | |
c09595f6 | 1539 | moved_load = __load_balance_fair(this_rq, this_cpu, busiest, |
53fecd8a | 1540 | rem_load, sd, idle, all_pinned, this_best_prio, |
c09595f6 | 1541 | tg->cfs_rq[busiest_cpu]); |
bf0f6f24 | 1542 | |
c09595f6 | 1543 | if (!moved_load) |
bf0f6f24 IM |
1544 | continue; |
1545 | ||
42a3ac7d | 1546 | moved_load *= busiest_h_load; |
243e0e7b | 1547 | moved_load = div_u64(moved_load, busiest_weight + 1); |
bf0f6f24 | 1548 | |
c09595f6 PZ |
1549 | rem_load_move -= moved_load; |
1550 | if (rem_load_move < 0) | |
bf0f6f24 IM |
1551 | break; |
1552 | } | |
c09595f6 | 1553 | rcu_read_unlock(); |
bf0f6f24 | 1554 | |
43010659 | 1555 | return max_load_move - rem_load_move; |
bf0f6f24 | 1556 | } |
c09595f6 PZ |
1557 | #else |
1558 | static unsigned long | |
1559 | load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
1560 | unsigned long max_load_move, | |
1561 | struct sched_domain *sd, enum cpu_idle_type idle, | |
1562 | int *all_pinned, int *this_best_prio) | |
1563 | { | |
1564 | return __load_balance_fair(this_rq, this_cpu, busiest, | |
1565 | max_load_move, sd, idle, all_pinned, | |
1566 | this_best_prio, &busiest->cfs); | |
1567 | } | |
1568 | #endif | |
bf0f6f24 | 1569 | |
e1d1484f PW |
1570 | static int |
1571 | move_one_task_fair(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
1572 | struct sched_domain *sd, enum cpu_idle_type idle) | |
1573 | { | |
1574 | struct cfs_rq *busy_cfs_rq; | |
1575 | struct rq_iterator cfs_rq_iterator; | |
1576 | ||
1577 | cfs_rq_iterator.start = load_balance_start_fair; | |
1578 | cfs_rq_iterator.next = load_balance_next_fair; | |
1579 | ||
1580 | for_each_leaf_cfs_rq(busiest, busy_cfs_rq) { | |
1581 | /* | |
1582 | * pass busy_cfs_rq argument into | |
1583 | * load_balance_[start|next]_fair iterators | |
1584 | */ | |
1585 | cfs_rq_iterator.arg = busy_cfs_rq; | |
1586 | if (iter_move_one_task(this_rq, this_cpu, busiest, sd, idle, | |
1587 | &cfs_rq_iterator)) | |
1588 | return 1; | |
1589 | } | |
1590 | ||
1591 | return 0; | |
1592 | } | |
55e12e5e | 1593 | #endif /* CONFIG_SMP */ |
e1d1484f | 1594 | |
bf0f6f24 IM |
1595 | /* |
1596 | * scheduler tick hitting a task of our scheduling class: | |
1597 | */ | |
8f4d37ec | 1598 | static void task_tick_fair(struct rq *rq, struct task_struct *curr, int queued) |
bf0f6f24 IM |
1599 | { |
1600 | struct cfs_rq *cfs_rq; | |
1601 | struct sched_entity *se = &curr->se; | |
1602 | ||
1603 | for_each_sched_entity(se) { | |
1604 | cfs_rq = cfs_rq_of(se); | |
8f4d37ec | 1605 | entity_tick(cfs_rq, se, queued); |
bf0f6f24 IM |
1606 | } |
1607 | } | |
1608 | ||
8eb172d9 | 1609 | #define swap(a, b) do { typeof(a) tmp = (a); (a) = (b); (b) = tmp; } while (0) |
4d78e7b6 | 1610 | |
bf0f6f24 IM |
1611 | /* |
1612 | * Share the fairness runtime between parent and child, thus the | |
1613 | * total amount of pressure for CPU stays equal - new tasks | |
1614 | * get a chance to run but frequent forkers are not allowed to | |
1615 | * monopolize the CPU. Note: the parent runqueue is locked, | |
1616 | * the child is not running yet. | |
1617 | */ | |
ee0827d8 | 1618 | static void task_new_fair(struct rq *rq, struct task_struct *p) |
bf0f6f24 IM |
1619 | { |
1620 | struct cfs_rq *cfs_rq = task_cfs_rq(p); | |
429d43bc | 1621 | struct sched_entity *se = &p->se, *curr = cfs_rq->curr; |
00bf7bfc | 1622 | int this_cpu = smp_processor_id(); |
bf0f6f24 IM |
1623 | |
1624 | sched_info_queued(p); | |
1625 | ||
7109c442 | 1626 | update_curr(cfs_rq); |
aeb73b04 | 1627 | place_entity(cfs_rq, se, 1); |
4d78e7b6 | 1628 | |
3c90e6e9 | 1629 | /* 'curr' will be NULL if the child belongs to a different group */ |
00bf7bfc | 1630 | if (sysctl_sched_child_runs_first && this_cpu == task_cpu(p) && |
3c90e6e9 | 1631 | curr && curr->vruntime < se->vruntime) { |
87fefa38 | 1632 | /* |
edcb60a3 IM |
1633 | * Upon rescheduling, sched_class::put_prev_task() will place |
1634 | * 'current' within the tree based on its new key value. | |
1635 | */ | |
4d78e7b6 | 1636 | swap(curr->vruntime, se->vruntime); |
aec0a514 | 1637 | resched_task(rq->curr); |
4d78e7b6 | 1638 | } |
bf0f6f24 | 1639 | |
b9dca1e0 | 1640 | enqueue_task_fair(rq, p, 0); |
bf0f6f24 IM |
1641 | } |
1642 | ||
cb469845 SR |
1643 | /* |
1644 | * Priority of the task has changed. Check to see if we preempt | |
1645 | * the current task. | |
1646 | */ | |
1647 | static void prio_changed_fair(struct rq *rq, struct task_struct *p, | |
1648 | int oldprio, int running) | |
1649 | { | |
1650 | /* | |
1651 | * Reschedule if we are currently running on this runqueue and | |
1652 | * our priority decreased, or if we are not currently running on | |
1653 | * this runqueue and our priority is higher than the current's | |
1654 | */ | |
1655 | if (running) { | |
1656 | if (p->prio > oldprio) | |
1657 | resched_task(rq->curr); | |
1658 | } else | |
15afe09b | 1659 | check_preempt_curr(rq, p, 0); |
cb469845 SR |
1660 | } |
1661 | ||
1662 | /* | |
1663 | * We switched to the sched_fair class. | |
1664 | */ | |
1665 | static void switched_to_fair(struct rq *rq, struct task_struct *p, | |
1666 | int running) | |
1667 | { | |
1668 | /* | |
1669 | * We were most likely switched from sched_rt, so | |
1670 | * kick off the schedule if running, otherwise just see | |
1671 | * if we can still preempt the current task. | |
1672 | */ | |
1673 | if (running) | |
1674 | resched_task(rq->curr); | |
1675 | else | |
15afe09b | 1676 | check_preempt_curr(rq, p, 0); |
cb469845 SR |
1677 | } |
1678 | ||
83b699ed SV |
1679 | /* Account for a task changing its policy or group. |
1680 | * | |
1681 | * This routine is mostly called to set cfs_rq->curr field when a task | |
1682 | * migrates between groups/classes. | |
1683 | */ | |
1684 | static void set_curr_task_fair(struct rq *rq) | |
1685 | { | |
1686 | struct sched_entity *se = &rq->curr->se; | |
1687 | ||
1688 | for_each_sched_entity(se) | |
1689 | set_next_entity(cfs_rq_of(se), se); | |
1690 | } | |
1691 | ||
810b3817 PZ |
1692 | #ifdef CONFIG_FAIR_GROUP_SCHED |
1693 | static void moved_group_fair(struct task_struct *p) | |
1694 | { | |
1695 | struct cfs_rq *cfs_rq = task_cfs_rq(p); | |
1696 | ||
1697 | update_curr(cfs_rq); | |
1698 | place_entity(cfs_rq, &p->se, 1); | |
1699 | } | |
1700 | #endif | |
1701 | ||
bf0f6f24 IM |
1702 | /* |
1703 | * All the scheduling class methods: | |
1704 | */ | |
5522d5d5 IM |
1705 | static const struct sched_class fair_sched_class = { |
1706 | .next = &idle_sched_class, | |
bf0f6f24 IM |
1707 | .enqueue_task = enqueue_task_fair, |
1708 | .dequeue_task = dequeue_task_fair, | |
1709 | .yield_task = yield_task_fair, | |
1710 | ||
2e09bf55 | 1711 | .check_preempt_curr = check_preempt_wakeup, |
bf0f6f24 IM |
1712 | |
1713 | .pick_next_task = pick_next_task_fair, | |
1714 | .put_prev_task = put_prev_task_fair, | |
1715 | ||
681f3e68 | 1716 | #ifdef CONFIG_SMP |
4ce72a2c LZ |
1717 | .select_task_rq = select_task_rq_fair, |
1718 | ||
bf0f6f24 | 1719 | .load_balance = load_balance_fair, |
e1d1484f | 1720 | .move_one_task = move_one_task_fair, |
681f3e68 | 1721 | #endif |
bf0f6f24 | 1722 | |
83b699ed | 1723 | .set_curr_task = set_curr_task_fair, |
bf0f6f24 IM |
1724 | .task_tick = task_tick_fair, |
1725 | .task_new = task_new_fair, | |
cb469845 SR |
1726 | |
1727 | .prio_changed = prio_changed_fair, | |
1728 | .switched_to = switched_to_fair, | |
810b3817 PZ |
1729 | |
1730 | #ifdef CONFIG_FAIR_GROUP_SCHED | |
1731 | .moved_group = moved_group_fair, | |
1732 | #endif | |
bf0f6f24 IM |
1733 | }; |
1734 | ||
1735 | #ifdef CONFIG_SCHED_DEBUG | |
5cef9eca | 1736 | static void print_cfs_stats(struct seq_file *m, int cpu) |
bf0f6f24 | 1737 | { |
bf0f6f24 IM |
1738 | struct cfs_rq *cfs_rq; |
1739 | ||
5973e5b9 | 1740 | rcu_read_lock(); |
c3b64f1e | 1741 | for_each_leaf_cfs_rq(cpu_rq(cpu), cfs_rq) |
5cef9eca | 1742 | print_cfs_rq(m, cpu, cfs_rq); |
5973e5b9 | 1743 | rcu_read_unlock(); |
bf0f6f24 IM |
1744 | } |
1745 | #endif |