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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 | 23 | #include <linux/latencytop.h> |
1983a922 | 24 | #include <linux/sched.h> |
3436ae12 | 25 | #include <linux/cpumask.h> |
9745512c | 26 | |
bf0f6f24 | 27 | /* |
21805085 | 28 | * Targeted preemption latency for CPU-bound tasks: |
864616ee | 29 | * (default: 6ms * (1 + ilog(ncpus)), units: nanoseconds) |
bf0f6f24 | 30 | * |
21805085 | 31 | * NOTE: this latency value is not the same as the concept of |
d274a4ce IM |
32 | * 'timeslice length' - timeslices in CFS are of variable length |
33 | * and have no persistent notion like in traditional, time-slice | |
34 | * based scheduling concepts. | |
bf0f6f24 | 35 | * |
d274a4ce IM |
36 | * (to see the precise effective timeslice length of your workload, |
37 | * run vmstat and monitor the context-switches (cs) field) | |
bf0f6f24 | 38 | */ |
21406928 MG |
39 | unsigned int sysctl_sched_latency = 6000000ULL; |
40 | unsigned int normalized_sysctl_sched_latency = 6000000ULL; | |
2bd8e6d4 | 41 | |
1983a922 CE |
42 | /* |
43 | * The initial- and re-scaling of tunables is configurable | |
44 | * (default SCHED_TUNABLESCALING_LOG = *(1+ilog(ncpus)) | |
45 | * | |
46 | * Options are: | |
47 | * SCHED_TUNABLESCALING_NONE - unscaled, always *1 | |
48 | * SCHED_TUNABLESCALING_LOG - scaled logarithmical, *1+ilog(ncpus) | |
49 | * SCHED_TUNABLESCALING_LINEAR - scaled linear, *ncpus | |
50 | */ | |
51 | enum sched_tunable_scaling sysctl_sched_tunable_scaling | |
52 | = SCHED_TUNABLESCALING_LOG; | |
53 | ||
2bd8e6d4 | 54 | /* |
b2be5e96 | 55 | * Minimal preemption granularity for CPU-bound tasks: |
864616ee | 56 | * (default: 0.75 msec * (1 + ilog(ncpus)), units: nanoseconds) |
2bd8e6d4 | 57 | */ |
0bf377bb IM |
58 | unsigned int sysctl_sched_min_granularity = 750000ULL; |
59 | unsigned int normalized_sysctl_sched_min_granularity = 750000ULL; | |
21805085 PZ |
60 | |
61 | /* | |
b2be5e96 PZ |
62 | * is kept at sysctl_sched_latency / sysctl_sched_min_granularity |
63 | */ | |
0bf377bb | 64 | static unsigned int sched_nr_latency = 8; |
b2be5e96 PZ |
65 | |
66 | /* | |
2bba22c5 | 67 | * After fork, child runs first. If set to 0 (default) then |
b2be5e96 | 68 | * parent will (try to) run first. |
21805085 | 69 | */ |
2bba22c5 | 70 | unsigned int sysctl_sched_child_runs_first __read_mostly; |
bf0f6f24 | 71 | |
bf0f6f24 IM |
72 | /* |
73 | * SCHED_OTHER wake-up granularity. | |
172e082a | 74 | * (default: 1 msec * (1 + ilog(ncpus)), units: nanoseconds) |
bf0f6f24 IM |
75 | * |
76 | * This option delays the preemption effects of decoupled workloads | |
77 | * and reduces their over-scheduling. Synchronous workloads will still | |
78 | * have immediate wakeup/sleep latencies. | |
79 | */ | |
172e082a | 80 | unsigned int sysctl_sched_wakeup_granularity = 1000000UL; |
0bcdcf28 | 81 | unsigned int normalized_sysctl_sched_wakeup_granularity = 1000000UL; |
bf0f6f24 | 82 | |
da84d961 IM |
83 | const_debug unsigned int sysctl_sched_migration_cost = 500000UL; |
84 | ||
a7a4f8a7 PT |
85 | /* |
86 | * The exponential sliding window over which load is averaged for shares | |
87 | * distribution. | |
88 | * (default: 10msec) | |
89 | */ | |
90 | unsigned int __read_mostly sysctl_sched_shares_window = 10000000UL; | |
91 | ||
ec12cb7f PT |
92 | #ifdef CONFIG_CFS_BANDWIDTH |
93 | /* | |
94 | * Amount of runtime to allocate from global (tg) to local (per-cfs_rq) pool | |
95 | * each time a cfs_rq requests quota. | |
96 | * | |
97 | * Note: in the case that the slice exceeds the runtime remaining (either due | |
98 | * to consumption or the quota being specified to be smaller than the slice) | |
99 | * we will always only issue the remaining available time. | |
100 | * | |
101 | * default: 5 msec, units: microseconds | |
102 | */ | |
103 | unsigned int sysctl_sched_cfs_bandwidth_slice = 5000UL; | |
104 | #endif | |
105 | ||
a4c2f00f PZ |
106 | static const struct sched_class fair_sched_class; |
107 | ||
bf0f6f24 IM |
108 | /************************************************************** |
109 | * CFS operations on generic schedulable entities: | |
110 | */ | |
111 | ||
62160e3f | 112 | #ifdef CONFIG_FAIR_GROUP_SCHED |
bf0f6f24 | 113 | |
62160e3f | 114 | /* cpu runqueue to which this cfs_rq is attached */ |
bf0f6f24 IM |
115 | static inline struct rq *rq_of(struct cfs_rq *cfs_rq) |
116 | { | |
62160e3f | 117 | return cfs_rq->rq; |
bf0f6f24 IM |
118 | } |
119 | ||
62160e3f IM |
120 | /* An entity is a task if it doesn't "own" a runqueue */ |
121 | #define entity_is_task(se) (!se->my_q) | |
bf0f6f24 | 122 | |
8f48894f PZ |
123 | static inline struct task_struct *task_of(struct sched_entity *se) |
124 | { | |
125 | #ifdef CONFIG_SCHED_DEBUG | |
126 | WARN_ON_ONCE(!entity_is_task(se)); | |
127 | #endif | |
128 | return container_of(se, struct task_struct, se); | |
129 | } | |
130 | ||
b758149c PZ |
131 | /* Walk up scheduling entities hierarchy */ |
132 | #define for_each_sched_entity(se) \ | |
133 | for (; se; se = se->parent) | |
134 | ||
135 | static inline struct cfs_rq *task_cfs_rq(struct task_struct *p) | |
136 | { | |
137 | return p->se.cfs_rq; | |
138 | } | |
139 | ||
140 | /* runqueue on which this entity is (to be) queued */ | |
141 | static inline struct cfs_rq *cfs_rq_of(struct sched_entity *se) | |
142 | { | |
143 | return se->cfs_rq; | |
144 | } | |
145 | ||
146 | /* runqueue "owned" by this group */ | |
147 | static inline struct cfs_rq *group_cfs_rq(struct sched_entity *grp) | |
148 | { | |
149 | return grp->my_q; | |
150 | } | |
151 | ||
3d4b47b4 PZ |
152 | static inline void list_add_leaf_cfs_rq(struct cfs_rq *cfs_rq) |
153 | { | |
154 | if (!cfs_rq->on_list) { | |
67e86250 PT |
155 | /* |
156 | * Ensure we either appear before our parent (if already | |
157 | * enqueued) or force our parent to appear after us when it is | |
158 | * enqueued. The fact that we always enqueue bottom-up | |
159 | * reduces this to two cases. | |
160 | */ | |
161 | if (cfs_rq->tg->parent && | |
162 | cfs_rq->tg->parent->cfs_rq[cpu_of(rq_of(cfs_rq))]->on_list) { | |
163 | list_add_rcu(&cfs_rq->leaf_cfs_rq_list, | |
164 | &rq_of(cfs_rq)->leaf_cfs_rq_list); | |
165 | } else { | |
166 | list_add_tail_rcu(&cfs_rq->leaf_cfs_rq_list, | |
3d4b47b4 | 167 | &rq_of(cfs_rq)->leaf_cfs_rq_list); |
67e86250 | 168 | } |
3d4b47b4 PZ |
169 | |
170 | cfs_rq->on_list = 1; | |
171 | } | |
172 | } | |
173 | ||
174 | static inline void list_del_leaf_cfs_rq(struct cfs_rq *cfs_rq) | |
175 | { | |
176 | if (cfs_rq->on_list) { | |
177 | list_del_rcu(&cfs_rq->leaf_cfs_rq_list); | |
178 | cfs_rq->on_list = 0; | |
179 | } | |
180 | } | |
181 | ||
b758149c PZ |
182 | /* Iterate thr' all leaf cfs_rq's on a runqueue */ |
183 | #define for_each_leaf_cfs_rq(rq, cfs_rq) \ | |
184 | list_for_each_entry_rcu(cfs_rq, &rq->leaf_cfs_rq_list, leaf_cfs_rq_list) | |
185 | ||
186 | /* Do the two (enqueued) entities belong to the same group ? */ | |
187 | static inline int | |
188 | is_same_group(struct sched_entity *se, struct sched_entity *pse) | |
189 | { | |
190 | if (se->cfs_rq == pse->cfs_rq) | |
191 | return 1; | |
192 | ||
193 | return 0; | |
194 | } | |
195 | ||
196 | static inline struct sched_entity *parent_entity(struct sched_entity *se) | |
197 | { | |
198 | return se->parent; | |
199 | } | |
200 | ||
464b7527 PZ |
201 | /* return depth at which a sched entity is present in the hierarchy */ |
202 | static inline int depth_se(struct sched_entity *se) | |
203 | { | |
204 | int depth = 0; | |
205 | ||
206 | for_each_sched_entity(se) | |
207 | depth++; | |
208 | ||
209 | return depth; | |
210 | } | |
211 | ||
212 | static void | |
213 | find_matching_se(struct sched_entity **se, struct sched_entity **pse) | |
214 | { | |
215 | int se_depth, pse_depth; | |
216 | ||
217 | /* | |
218 | * preemption test can be made between sibling entities who are in the | |
219 | * same cfs_rq i.e who have a common parent. Walk up the hierarchy of | |
220 | * both tasks until we find their ancestors who are siblings of common | |
221 | * parent. | |
222 | */ | |
223 | ||
224 | /* First walk up until both entities are at same depth */ | |
225 | se_depth = depth_se(*se); | |
226 | pse_depth = depth_se(*pse); | |
227 | ||
228 | while (se_depth > pse_depth) { | |
229 | se_depth--; | |
230 | *se = parent_entity(*se); | |
231 | } | |
232 | ||
233 | while (pse_depth > se_depth) { | |
234 | pse_depth--; | |
235 | *pse = parent_entity(*pse); | |
236 | } | |
237 | ||
238 | while (!is_same_group(*se, *pse)) { | |
239 | *se = parent_entity(*se); | |
240 | *pse = parent_entity(*pse); | |
241 | } | |
242 | } | |
243 | ||
8f48894f PZ |
244 | #else /* !CONFIG_FAIR_GROUP_SCHED */ |
245 | ||
246 | static inline struct task_struct *task_of(struct sched_entity *se) | |
247 | { | |
248 | return container_of(se, struct task_struct, se); | |
249 | } | |
bf0f6f24 | 250 | |
62160e3f IM |
251 | static inline struct rq *rq_of(struct cfs_rq *cfs_rq) |
252 | { | |
253 | return container_of(cfs_rq, struct rq, cfs); | |
bf0f6f24 IM |
254 | } |
255 | ||
256 | #define entity_is_task(se) 1 | |
257 | ||
b758149c PZ |
258 | #define for_each_sched_entity(se) \ |
259 | for (; se; se = NULL) | |
bf0f6f24 | 260 | |
b758149c | 261 | static inline struct cfs_rq *task_cfs_rq(struct task_struct *p) |
bf0f6f24 | 262 | { |
b758149c | 263 | return &task_rq(p)->cfs; |
bf0f6f24 IM |
264 | } |
265 | ||
b758149c PZ |
266 | static inline struct cfs_rq *cfs_rq_of(struct sched_entity *se) |
267 | { | |
268 | struct task_struct *p = task_of(se); | |
269 | struct rq *rq = task_rq(p); | |
270 | ||
271 | return &rq->cfs; | |
272 | } | |
273 | ||
274 | /* runqueue "owned" by this group */ | |
275 | static inline struct cfs_rq *group_cfs_rq(struct sched_entity *grp) | |
276 | { | |
277 | return NULL; | |
278 | } | |
279 | ||
3d4b47b4 PZ |
280 | static inline void list_add_leaf_cfs_rq(struct cfs_rq *cfs_rq) |
281 | { | |
282 | } | |
283 | ||
284 | static inline void list_del_leaf_cfs_rq(struct cfs_rq *cfs_rq) | |
285 | { | |
286 | } | |
287 | ||
b758149c PZ |
288 | #define for_each_leaf_cfs_rq(rq, cfs_rq) \ |
289 | for (cfs_rq = &rq->cfs; cfs_rq; cfs_rq = NULL) | |
290 | ||
291 | static inline int | |
292 | is_same_group(struct sched_entity *se, struct sched_entity *pse) | |
293 | { | |
294 | return 1; | |
295 | } | |
296 | ||
297 | static inline struct sched_entity *parent_entity(struct sched_entity *se) | |
298 | { | |
299 | return NULL; | |
300 | } | |
301 | ||
464b7527 PZ |
302 | static inline void |
303 | find_matching_se(struct sched_entity **se, struct sched_entity **pse) | |
304 | { | |
305 | } | |
306 | ||
b758149c PZ |
307 | #endif /* CONFIG_FAIR_GROUP_SCHED */ |
308 | ||
ec12cb7f PT |
309 | static void account_cfs_rq_runtime(struct cfs_rq *cfs_rq, |
310 | unsigned long delta_exec); | |
bf0f6f24 IM |
311 | |
312 | /************************************************************** | |
313 | * Scheduling class tree data structure manipulation methods: | |
314 | */ | |
315 | ||
0702e3eb | 316 | static inline u64 max_vruntime(u64 min_vruntime, u64 vruntime) |
02e0431a | 317 | { |
368059a9 PZ |
318 | s64 delta = (s64)(vruntime - min_vruntime); |
319 | if (delta > 0) | |
02e0431a PZ |
320 | min_vruntime = vruntime; |
321 | ||
322 | return min_vruntime; | |
323 | } | |
324 | ||
0702e3eb | 325 | static inline u64 min_vruntime(u64 min_vruntime, u64 vruntime) |
b0ffd246 PZ |
326 | { |
327 | s64 delta = (s64)(vruntime - min_vruntime); | |
328 | if (delta < 0) | |
329 | min_vruntime = vruntime; | |
330 | ||
331 | return min_vruntime; | |
332 | } | |
333 | ||
54fdc581 FC |
334 | static inline int entity_before(struct sched_entity *a, |
335 | struct sched_entity *b) | |
336 | { | |
337 | return (s64)(a->vruntime - b->vruntime) < 0; | |
338 | } | |
339 | ||
1af5f730 PZ |
340 | static void update_min_vruntime(struct cfs_rq *cfs_rq) |
341 | { | |
342 | u64 vruntime = cfs_rq->min_vruntime; | |
343 | ||
344 | if (cfs_rq->curr) | |
345 | vruntime = cfs_rq->curr->vruntime; | |
346 | ||
347 | if (cfs_rq->rb_leftmost) { | |
348 | struct sched_entity *se = rb_entry(cfs_rq->rb_leftmost, | |
349 | struct sched_entity, | |
350 | run_node); | |
351 | ||
e17036da | 352 | if (!cfs_rq->curr) |
1af5f730 PZ |
353 | vruntime = se->vruntime; |
354 | else | |
355 | vruntime = min_vruntime(vruntime, se->vruntime); | |
356 | } | |
357 | ||
358 | cfs_rq->min_vruntime = max_vruntime(cfs_rq->min_vruntime, vruntime); | |
3fe1698b PZ |
359 | #ifndef CONFIG_64BIT |
360 | smp_wmb(); | |
361 | cfs_rq->min_vruntime_copy = cfs_rq->min_vruntime; | |
362 | #endif | |
1af5f730 PZ |
363 | } |
364 | ||
bf0f6f24 IM |
365 | /* |
366 | * Enqueue an entity into the rb-tree: | |
367 | */ | |
0702e3eb | 368 | static void __enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 IM |
369 | { |
370 | struct rb_node **link = &cfs_rq->tasks_timeline.rb_node; | |
371 | struct rb_node *parent = NULL; | |
372 | struct sched_entity *entry; | |
bf0f6f24 IM |
373 | int leftmost = 1; |
374 | ||
375 | /* | |
376 | * Find the right place in the rbtree: | |
377 | */ | |
378 | while (*link) { | |
379 | parent = *link; | |
380 | entry = rb_entry(parent, struct sched_entity, run_node); | |
381 | /* | |
382 | * We dont care about collisions. Nodes with | |
383 | * the same key stay together. | |
384 | */ | |
2bd2d6f2 | 385 | if (entity_before(se, entry)) { |
bf0f6f24 IM |
386 | link = &parent->rb_left; |
387 | } else { | |
388 | link = &parent->rb_right; | |
389 | leftmost = 0; | |
390 | } | |
391 | } | |
392 | ||
393 | /* | |
394 | * Maintain a cache of leftmost tree entries (it is frequently | |
395 | * used): | |
396 | */ | |
1af5f730 | 397 | if (leftmost) |
57cb499d | 398 | cfs_rq->rb_leftmost = &se->run_node; |
bf0f6f24 IM |
399 | |
400 | rb_link_node(&se->run_node, parent, link); | |
401 | rb_insert_color(&se->run_node, &cfs_rq->tasks_timeline); | |
bf0f6f24 IM |
402 | } |
403 | ||
0702e3eb | 404 | static void __dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 405 | { |
3fe69747 PZ |
406 | if (cfs_rq->rb_leftmost == &se->run_node) { |
407 | struct rb_node *next_node; | |
3fe69747 PZ |
408 | |
409 | next_node = rb_next(&se->run_node); | |
410 | cfs_rq->rb_leftmost = next_node; | |
3fe69747 | 411 | } |
e9acbff6 | 412 | |
bf0f6f24 | 413 | rb_erase(&se->run_node, &cfs_rq->tasks_timeline); |
bf0f6f24 IM |
414 | } |
415 | ||
ac53db59 | 416 | static struct sched_entity *__pick_first_entity(struct cfs_rq *cfs_rq) |
bf0f6f24 | 417 | { |
f4b6755f PZ |
418 | struct rb_node *left = cfs_rq->rb_leftmost; |
419 | ||
420 | if (!left) | |
421 | return NULL; | |
422 | ||
423 | return rb_entry(left, struct sched_entity, run_node); | |
bf0f6f24 IM |
424 | } |
425 | ||
ac53db59 RR |
426 | static struct sched_entity *__pick_next_entity(struct sched_entity *se) |
427 | { | |
428 | struct rb_node *next = rb_next(&se->run_node); | |
429 | ||
430 | if (!next) | |
431 | return NULL; | |
432 | ||
433 | return rb_entry(next, struct sched_entity, run_node); | |
434 | } | |
435 | ||
436 | #ifdef CONFIG_SCHED_DEBUG | |
f4b6755f | 437 | static struct sched_entity *__pick_last_entity(struct cfs_rq *cfs_rq) |
aeb73b04 | 438 | { |
7eee3e67 | 439 | struct rb_node *last = rb_last(&cfs_rq->tasks_timeline); |
aeb73b04 | 440 | |
70eee74b BS |
441 | if (!last) |
442 | return NULL; | |
7eee3e67 IM |
443 | |
444 | return rb_entry(last, struct sched_entity, run_node); | |
aeb73b04 PZ |
445 | } |
446 | ||
bf0f6f24 IM |
447 | /************************************************************** |
448 | * Scheduling class statistics methods: | |
449 | */ | |
450 | ||
acb4a848 | 451 | int sched_proc_update_handler(struct ctl_table *table, int write, |
8d65af78 | 452 | void __user *buffer, size_t *lenp, |
b2be5e96 PZ |
453 | loff_t *ppos) |
454 | { | |
8d65af78 | 455 | int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); |
acb4a848 | 456 | int factor = get_update_sysctl_factor(); |
b2be5e96 PZ |
457 | |
458 | if (ret || !write) | |
459 | return ret; | |
460 | ||
461 | sched_nr_latency = DIV_ROUND_UP(sysctl_sched_latency, | |
462 | sysctl_sched_min_granularity); | |
463 | ||
acb4a848 CE |
464 | #define WRT_SYSCTL(name) \ |
465 | (normalized_sysctl_##name = sysctl_##name / (factor)) | |
466 | WRT_SYSCTL(sched_min_granularity); | |
467 | WRT_SYSCTL(sched_latency); | |
468 | WRT_SYSCTL(sched_wakeup_granularity); | |
acb4a848 CE |
469 | #undef WRT_SYSCTL |
470 | ||
b2be5e96 PZ |
471 | return 0; |
472 | } | |
473 | #endif | |
647e7cac | 474 | |
a7be37ac | 475 | /* |
f9c0b095 | 476 | * delta /= w |
a7be37ac PZ |
477 | */ |
478 | static inline unsigned long | |
479 | calc_delta_fair(unsigned long delta, struct sched_entity *se) | |
480 | { | |
f9c0b095 PZ |
481 | if (unlikely(se->load.weight != NICE_0_LOAD)) |
482 | delta = calc_delta_mine(delta, NICE_0_LOAD, &se->load); | |
a7be37ac PZ |
483 | |
484 | return delta; | |
485 | } | |
486 | ||
647e7cac IM |
487 | /* |
488 | * The idea is to set a period in which each task runs once. | |
489 | * | |
490 | * When there are too many tasks (sysctl_sched_nr_latency) we have to stretch | |
491 | * this period because otherwise the slices get too small. | |
492 | * | |
493 | * p = (nr <= nl) ? l : l*nr/nl | |
494 | */ | |
4d78e7b6 PZ |
495 | static u64 __sched_period(unsigned long nr_running) |
496 | { | |
497 | u64 period = sysctl_sched_latency; | |
b2be5e96 | 498 | unsigned long nr_latency = sched_nr_latency; |
4d78e7b6 PZ |
499 | |
500 | if (unlikely(nr_running > nr_latency)) { | |
4bf0b771 | 501 | period = sysctl_sched_min_granularity; |
4d78e7b6 | 502 | period *= nr_running; |
4d78e7b6 PZ |
503 | } |
504 | ||
505 | return period; | |
506 | } | |
507 | ||
647e7cac IM |
508 | /* |
509 | * We calculate the wall-time slice from the period by taking a part | |
510 | * proportional to the weight. | |
511 | * | |
f9c0b095 | 512 | * s = p*P[w/rw] |
647e7cac | 513 | */ |
6d0f0ebd | 514 | static u64 sched_slice(struct cfs_rq *cfs_rq, struct sched_entity *se) |
21805085 | 515 | { |
0a582440 | 516 | u64 slice = __sched_period(cfs_rq->nr_running + !se->on_rq); |
f9c0b095 | 517 | |
0a582440 | 518 | for_each_sched_entity(se) { |
6272d68c | 519 | struct load_weight *load; |
3104bf03 | 520 | struct load_weight lw; |
6272d68c LM |
521 | |
522 | cfs_rq = cfs_rq_of(se); | |
523 | load = &cfs_rq->load; | |
f9c0b095 | 524 | |
0a582440 | 525 | if (unlikely(!se->on_rq)) { |
3104bf03 | 526 | lw = cfs_rq->load; |
0a582440 MG |
527 | |
528 | update_load_add(&lw, se->load.weight); | |
529 | load = &lw; | |
530 | } | |
531 | slice = calc_delta_mine(slice, se->load.weight, load); | |
532 | } | |
533 | return slice; | |
bf0f6f24 IM |
534 | } |
535 | ||
647e7cac | 536 | /* |
ac884dec | 537 | * We calculate the vruntime slice of a to be inserted task |
647e7cac | 538 | * |
f9c0b095 | 539 | * vs = s/w |
647e7cac | 540 | */ |
f9c0b095 | 541 | static u64 sched_vslice(struct cfs_rq *cfs_rq, struct sched_entity *se) |
67e9fb2a | 542 | { |
f9c0b095 | 543 | return calc_delta_fair(sched_slice(cfs_rq, se), se); |
a7be37ac PZ |
544 | } |
545 | ||
d6b55918 | 546 | static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update); |
6d5ab293 | 547 | static void update_cfs_shares(struct cfs_rq *cfs_rq); |
3b3d190e | 548 | |
bf0f6f24 IM |
549 | /* |
550 | * Update the current task's runtime statistics. Skip current tasks that | |
551 | * are not in our scheduling class. | |
552 | */ | |
553 | static inline void | |
8ebc91d9 IM |
554 | __update_curr(struct cfs_rq *cfs_rq, struct sched_entity *curr, |
555 | unsigned long delta_exec) | |
bf0f6f24 | 556 | { |
bbdba7c0 | 557 | unsigned long delta_exec_weighted; |
bf0f6f24 | 558 | |
41acab88 LDM |
559 | schedstat_set(curr->statistics.exec_max, |
560 | max((u64)delta_exec, curr->statistics.exec_max)); | |
bf0f6f24 IM |
561 | |
562 | curr->sum_exec_runtime += delta_exec; | |
7a62eabc | 563 | schedstat_add(cfs_rq, exec_clock, delta_exec); |
a7be37ac | 564 | delta_exec_weighted = calc_delta_fair(delta_exec, curr); |
88ec22d3 | 565 | |
e9acbff6 | 566 | curr->vruntime += delta_exec_weighted; |
1af5f730 | 567 | update_min_vruntime(cfs_rq); |
3b3d190e | 568 | |
70caf8a6 | 569 | #if defined CONFIG_SMP && defined CONFIG_FAIR_GROUP_SCHED |
3b3d190e | 570 | cfs_rq->load_unacc_exec_time += delta_exec; |
3b3d190e | 571 | #endif |
bf0f6f24 IM |
572 | } |
573 | ||
b7cc0896 | 574 | static void update_curr(struct cfs_rq *cfs_rq) |
bf0f6f24 | 575 | { |
429d43bc | 576 | struct sched_entity *curr = cfs_rq->curr; |
305e6835 | 577 | u64 now = rq_of(cfs_rq)->clock_task; |
bf0f6f24 IM |
578 | unsigned long delta_exec; |
579 | ||
580 | if (unlikely(!curr)) | |
581 | return; | |
582 | ||
583 | /* | |
584 | * Get the amount of time the current task was running | |
585 | * since the last time we changed load (this cannot | |
586 | * overflow on 32 bits): | |
587 | */ | |
8ebc91d9 | 588 | delta_exec = (unsigned long)(now - curr->exec_start); |
34f28ecd PZ |
589 | if (!delta_exec) |
590 | return; | |
bf0f6f24 | 591 | |
8ebc91d9 IM |
592 | __update_curr(cfs_rq, curr, delta_exec); |
593 | curr->exec_start = now; | |
d842de87 SV |
594 | |
595 | if (entity_is_task(curr)) { | |
596 | struct task_struct *curtask = task_of(curr); | |
597 | ||
f977bb49 | 598 | trace_sched_stat_runtime(curtask, delta_exec, curr->vruntime); |
d842de87 | 599 | cpuacct_charge(curtask, delta_exec); |
f06febc9 | 600 | account_group_exec_runtime(curtask, delta_exec); |
d842de87 | 601 | } |
ec12cb7f PT |
602 | |
603 | account_cfs_rq_runtime(cfs_rq, delta_exec); | |
bf0f6f24 IM |
604 | } |
605 | ||
606 | static inline void | |
5870db5b | 607 | update_stats_wait_start(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 608 | { |
41acab88 | 609 | schedstat_set(se->statistics.wait_start, rq_of(cfs_rq)->clock); |
bf0f6f24 IM |
610 | } |
611 | ||
bf0f6f24 IM |
612 | /* |
613 | * Task is being enqueued - update stats: | |
614 | */ | |
d2417e5a | 615 | static void update_stats_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 616 | { |
bf0f6f24 IM |
617 | /* |
618 | * Are we enqueueing a waiting task? (for current tasks | |
619 | * a dequeue/enqueue event is a NOP) | |
620 | */ | |
429d43bc | 621 | if (se != cfs_rq->curr) |
5870db5b | 622 | update_stats_wait_start(cfs_rq, se); |
bf0f6f24 IM |
623 | } |
624 | ||
bf0f6f24 | 625 | static void |
9ef0a961 | 626 | update_stats_wait_end(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 627 | { |
41acab88 LDM |
628 | schedstat_set(se->statistics.wait_max, max(se->statistics.wait_max, |
629 | rq_of(cfs_rq)->clock - se->statistics.wait_start)); | |
630 | schedstat_set(se->statistics.wait_count, se->statistics.wait_count + 1); | |
631 | schedstat_set(se->statistics.wait_sum, se->statistics.wait_sum + | |
632 | rq_of(cfs_rq)->clock - se->statistics.wait_start); | |
768d0c27 PZ |
633 | #ifdef CONFIG_SCHEDSTATS |
634 | if (entity_is_task(se)) { | |
635 | trace_sched_stat_wait(task_of(se), | |
41acab88 | 636 | rq_of(cfs_rq)->clock - se->statistics.wait_start); |
768d0c27 PZ |
637 | } |
638 | #endif | |
41acab88 | 639 | schedstat_set(se->statistics.wait_start, 0); |
bf0f6f24 IM |
640 | } |
641 | ||
642 | static inline void | |
19b6a2e3 | 643 | update_stats_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 644 | { |
bf0f6f24 IM |
645 | /* |
646 | * Mark the end of the wait period if dequeueing a | |
647 | * waiting task: | |
648 | */ | |
429d43bc | 649 | if (se != cfs_rq->curr) |
9ef0a961 | 650 | update_stats_wait_end(cfs_rq, se); |
bf0f6f24 IM |
651 | } |
652 | ||
653 | /* | |
654 | * We are picking a new current task - update its stats: | |
655 | */ | |
656 | static inline void | |
79303e9e | 657 | update_stats_curr_start(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 IM |
658 | { |
659 | /* | |
660 | * We are starting a new run period: | |
661 | */ | |
305e6835 | 662 | se->exec_start = rq_of(cfs_rq)->clock_task; |
bf0f6f24 IM |
663 | } |
664 | ||
bf0f6f24 IM |
665 | /************************************************** |
666 | * Scheduling class queueing methods: | |
667 | */ | |
668 | ||
c09595f6 PZ |
669 | #if defined CONFIG_SMP && defined CONFIG_FAIR_GROUP_SCHED |
670 | static void | |
671 | add_cfs_task_weight(struct cfs_rq *cfs_rq, unsigned long weight) | |
672 | { | |
673 | cfs_rq->task_weight += weight; | |
674 | } | |
675 | #else | |
676 | static inline void | |
677 | add_cfs_task_weight(struct cfs_rq *cfs_rq, unsigned long weight) | |
678 | { | |
679 | } | |
680 | #endif | |
681 | ||
30cfdcfc DA |
682 | static void |
683 | account_entity_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se) | |
684 | { | |
685 | update_load_add(&cfs_rq->load, se->load.weight); | |
c09595f6 PZ |
686 | if (!parent_entity(se)) |
687 | inc_cpu_load(rq_of(cfs_rq), se->load.weight); | |
b87f1724 | 688 | if (entity_is_task(se)) { |
c09595f6 | 689 | add_cfs_task_weight(cfs_rq, se->load.weight); |
b87f1724 BR |
690 | list_add(&se->group_node, &cfs_rq->tasks); |
691 | } | |
30cfdcfc | 692 | cfs_rq->nr_running++; |
30cfdcfc DA |
693 | } |
694 | ||
695 | static void | |
696 | account_entity_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se) | |
697 | { | |
698 | update_load_sub(&cfs_rq->load, se->load.weight); | |
c09595f6 PZ |
699 | if (!parent_entity(se)) |
700 | dec_cpu_load(rq_of(cfs_rq), se->load.weight); | |
b87f1724 | 701 | if (entity_is_task(se)) { |
c09595f6 | 702 | add_cfs_task_weight(cfs_rq, -se->load.weight); |
b87f1724 BR |
703 | list_del_init(&se->group_node); |
704 | } | |
30cfdcfc | 705 | cfs_rq->nr_running--; |
30cfdcfc DA |
706 | } |
707 | ||
3ff6dcac | 708 | #ifdef CONFIG_FAIR_GROUP_SCHED |
64660c86 PT |
709 | /* we need this in update_cfs_load and load-balance functions below */ |
710 | static inline int throttled_hierarchy(struct cfs_rq *cfs_rq); | |
3ff6dcac | 711 | # ifdef CONFIG_SMP |
d6b55918 PT |
712 | static void update_cfs_rq_load_contribution(struct cfs_rq *cfs_rq, |
713 | int global_update) | |
714 | { | |
715 | struct task_group *tg = cfs_rq->tg; | |
716 | long load_avg; | |
717 | ||
718 | load_avg = div64_u64(cfs_rq->load_avg, cfs_rq->load_period+1); | |
719 | load_avg -= cfs_rq->load_contribution; | |
720 | ||
721 | if (global_update || abs(load_avg) > cfs_rq->load_contribution / 8) { | |
722 | atomic_add(load_avg, &tg->load_weight); | |
723 | cfs_rq->load_contribution += load_avg; | |
724 | } | |
725 | } | |
726 | ||
727 | static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update) | |
2069dd75 | 728 | { |
a7a4f8a7 | 729 | u64 period = sysctl_sched_shares_window; |
2069dd75 | 730 | u64 now, delta; |
e33078ba | 731 | unsigned long load = cfs_rq->load.weight; |
2069dd75 | 732 | |
64660c86 | 733 | if (cfs_rq->tg == &root_task_group || throttled_hierarchy(cfs_rq)) |
2069dd75 PZ |
734 | return; |
735 | ||
05ca62c6 | 736 | now = rq_of(cfs_rq)->clock_task; |
2069dd75 PZ |
737 | delta = now - cfs_rq->load_stamp; |
738 | ||
e33078ba PT |
739 | /* truncate load history at 4 idle periods */ |
740 | if (cfs_rq->load_stamp > cfs_rq->load_last && | |
741 | now - cfs_rq->load_last > 4 * period) { | |
742 | cfs_rq->load_period = 0; | |
743 | cfs_rq->load_avg = 0; | |
f07333bf | 744 | delta = period - 1; |
e33078ba PT |
745 | } |
746 | ||
2069dd75 | 747 | cfs_rq->load_stamp = now; |
3b3d190e | 748 | cfs_rq->load_unacc_exec_time = 0; |
2069dd75 | 749 | cfs_rq->load_period += delta; |
e33078ba PT |
750 | if (load) { |
751 | cfs_rq->load_last = now; | |
752 | cfs_rq->load_avg += delta * load; | |
753 | } | |
2069dd75 | 754 | |
d6b55918 PT |
755 | /* consider updating load contribution on each fold or truncate */ |
756 | if (global_update || cfs_rq->load_period > period | |
757 | || !cfs_rq->load_period) | |
758 | update_cfs_rq_load_contribution(cfs_rq, global_update); | |
759 | ||
2069dd75 PZ |
760 | while (cfs_rq->load_period > period) { |
761 | /* | |
762 | * Inline assembly required to prevent the compiler | |
763 | * optimising this loop into a divmod call. | |
764 | * See __iter_div_u64_rem() for another example of this. | |
765 | */ | |
766 | asm("" : "+rm" (cfs_rq->load_period)); | |
767 | cfs_rq->load_period /= 2; | |
768 | cfs_rq->load_avg /= 2; | |
769 | } | |
3d4b47b4 | 770 | |
e33078ba PT |
771 | if (!cfs_rq->curr && !cfs_rq->nr_running && !cfs_rq->load_avg) |
772 | list_del_leaf_cfs_rq(cfs_rq); | |
2069dd75 PZ |
773 | } |
774 | ||
cf5f0acf PZ |
775 | static inline long calc_tg_weight(struct task_group *tg, struct cfs_rq *cfs_rq) |
776 | { | |
777 | long tg_weight; | |
778 | ||
779 | /* | |
780 | * Use this CPU's actual weight instead of the last load_contribution | |
781 | * to gain a more accurate current total weight. See | |
782 | * update_cfs_rq_load_contribution(). | |
783 | */ | |
784 | tg_weight = atomic_read(&tg->load_weight); | |
785 | tg_weight -= cfs_rq->load_contribution; | |
786 | tg_weight += cfs_rq->load.weight; | |
787 | ||
788 | return tg_weight; | |
789 | } | |
790 | ||
6d5ab293 | 791 | static long calc_cfs_shares(struct cfs_rq *cfs_rq, struct task_group *tg) |
3ff6dcac | 792 | { |
cf5f0acf | 793 | long tg_weight, load, shares; |
3ff6dcac | 794 | |
cf5f0acf | 795 | tg_weight = calc_tg_weight(tg, cfs_rq); |
6d5ab293 | 796 | load = cfs_rq->load.weight; |
3ff6dcac | 797 | |
3ff6dcac | 798 | shares = (tg->shares * load); |
cf5f0acf PZ |
799 | if (tg_weight) |
800 | shares /= tg_weight; | |
3ff6dcac YZ |
801 | |
802 | if (shares < MIN_SHARES) | |
803 | shares = MIN_SHARES; | |
804 | if (shares > tg->shares) | |
805 | shares = tg->shares; | |
806 | ||
807 | return shares; | |
808 | } | |
809 | ||
810 | static void update_entity_shares_tick(struct cfs_rq *cfs_rq) | |
811 | { | |
812 | if (cfs_rq->load_unacc_exec_time > sysctl_sched_shares_window) { | |
813 | update_cfs_load(cfs_rq, 0); | |
6d5ab293 | 814 | update_cfs_shares(cfs_rq); |
3ff6dcac YZ |
815 | } |
816 | } | |
817 | # else /* CONFIG_SMP */ | |
818 | static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update) | |
819 | { | |
820 | } | |
821 | ||
6d5ab293 | 822 | static inline long calc_cfs_shares(struct cfs_rq *cfs_rq, struct task_group *tg) |
3ff6dcac YZ |
823 | { |
824 | return tg->shares; | |
825 | } | |
826 | ||
827 | static inline void update_entity_shares_tick(struct cfs_rq *cfs_rq) | |
828 | { | |
829 | } | |
830 | # endif /* CONFIG_SMP */ | |
2069dd75 PZ |
831 | static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, |
832 | unsigned long weight) | |
833 | { | |
19e5eebb PT |
834 | if (se->on_rq) { |
835 | /* commit outstanding execution time */ | |
836 | if (cfs_rq->curr == se) | |
837 | update_curr(cfs_rq); | |
2069dd75 | 838 | account_entity_dequeue(cfs_rq, se); |
19e5eebb | 839 | } |
2069dd75 PZ |
840 | |
841 | update_load_set(&se->load, weight); | |
842 | ||
843 | if (se->on_rq) | |
844 | account_entity_enqueue(cfs_rq, se); | |
845 | } | |
846 | ||
6d5ab293 | 847 | static void update_cfs_shares(struct cfs_rq *cfs_rq) |
2069dd75 PZ |
848 | { |
849 | struct task_group *tg; | |
850 | struct sched_entity *se; | |
3ff6dcac | 851 | long shares; |
2069dd75 | 852 | |
2069dd75 PZ |
853 | tg = cfs_rq->tg; |
854 | se = tg->se[cpu_of(rq_of(cfs_rq))]; | |
64660c86 | 855 | if (!se || throttled_hierarchy(cfs_rq)) |
2069dd75 | 856 | return; |
3ff6dcac YZ |
857 | #ifndef CONFIG_SMP |
858 | if (likely(se->load.weight == tg->shares)) | |
859 | return; | |
860 | #endif | |
6d5ab293 | 861 | shares = calc_cfs_shares(cfs_rq, tg); |
2069dd75 PZ |
862 | |
863 | reweight_entity(cfs_rq_of(se), se, shares); | |
864 | } | |
865 | #else /* CONFIG_FAIR_GROUP_SCHED */ | |
d6b55918 | 866 | static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update) |
2069dd75 PZ |
867 | { |
868 | } | |
869 | ||
6d5ab293 | 870 | static inline void update_cfs_shares(struct cfs_rq *cfs_rq) |
2069dd75 PZ |
871 | { |
872 | } | |
43365bd7 PT |
873 | |
874 | static inline void update_entity_shares_tick(struct cfs_rq *cfs_rq) | |
875 | { | |
876 | } | |
2069dd75 PZ |
877 | #endif /* CONFIG_FAIR_GROUP_SCHED */ |
878 | ||
2396af69 | 879 | static void enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 880 | { |
bf0f6f24 | 881 | #ifdef CONFIG_SCHEDSTATS |
e414314c PZ |
882 | struct task_struct *tsk = NULL; |
883 | ||
884 | if (entity_is_task(se)) | |
885 | tsk = task_of(se); | |
886 | ||
41acab88 LDM |
887 | if (se->statistics.sleep_start) { |
888 | u64 delta = rq_of(cfs_rq)->clock - se->statistics.sleep_start; | |
bf0f6f24 IM |
889 | |
890 | if ((s64)delta < 0) | |
891 | delta = 0; | |
892 | ||
41acab88 LDM |
893 | if (unlikely(delta > se->statistics.sleep_max)) |
894 | se->statistics.sleep_max = delta; | |
bf0f6f24 | 895 | |
41acab88 LDM |
896 | se->statistics.sleep_start = 0; |
897 | se->statistics.sum_sleep_runtime += delta; | |
9745512c | 898 | |
768d0c27 | 899 | if (tsk) { |
e414314c | 900 | account_scheduler_latency(tsk, delta >> 10, 1); |
768d0c27 PZ |
901 | trace_sched_stat_sleep(tsk, delta); |
902 | } | |
bf0f6f24 | 903 | } |
41acab88 LDM |
904 | if (se->statistics.block_start) { |
905 | u64 delta = rq_of(cfs_rq)->clock - se->statistics.block_start; | |
bf0f6f24 IM |
906 | |
907 | if ((s64)delta < 0) | |
908 | delta = 0; | |
909 | ||
41acab88 LDM |
910 | if (unlikely(delta > se->statistics.block_max)) |
911 | se->statistics.block_max = delta; | |
bf0f6f24 | 912 | |
41acab88 LDM |
913 | se->statistics.block_start = 0; |
914 | se->statistics.sum_sleep_runtime += delta; | |
30084fbd | 915 | |
e414314c | 916 | if (tsk) { |
8f0dfc34 | 917 | if (tsk->in_iowait) { |
41acab88 LDM |
918 | se->statistics.iowait_sum += delta; |
919 | se->statistics.iowait_count++; | |
768d0c27 | 920 | trace_sched_stat_iowait(tsk, delta); |
8f0dfc34 AV |
921 | } |
922 | ||
e414314c PZ |
923 | /* |
924 | * Blocking time is in units of nanosecs, so shift by | |
925 | * 20 to get a milliseconds-range estimation of the | |
926 | * amount of time that the task spent sleeping: | |
927 | */ | |
928 | if (unlikely(prof_on == SLEEP_PROFILING)) { | |
929 | profile_hits(SLEEP_PROFILING, | |
930 | (void *)get_wchan(tsk), | |
931 | delta >> 20); | |
932 | } | |
933 | account_scheduler_latency(tsk, delta >> 10, 0); | |
30084fbd | 934 | } |
bf0f6f24 IM |
935 | } |
936 | #endif | |
937 | } | |
938 | ||
ddc97297 PZ |
939 | static void check_spread(struct cfs_rq *cfs_rq, struct sched_entity *se) |
940 | { | |
941 | #ifdef CONFIG_SCHED_DEBUG | |
942 | s64 d = se->vruntime - cfs_rq->min_vruntime; | |
943 | ||
944 | if (d < 0) | |
945 | d = -d; | |
946 | ||
947 | if (d > 3*sysctl_sched_latency) | |
948 | schedstat_inc(cfs_rq, nr_spread_over); | |
949 | #endif | |
950 | } | |
951 | ||
aeb73b04 PZ |
952 | static void |
953 | place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial) | |
954 | { | |
1af5f730 | 955 | u64 vruntime = cfs_rq->min_vruntime; |
94dfb5e7 | 956 | |
2cb8600e PZ |
957 | /* |
958 | * The 'current' period is already promised to the current tasks, | |
959 | * however the extra weight of the new task will slow them down a | |
960 | * little, place the new task so that it fits in the slot that | |
961 | * stays open at the end. | |
962 | */ | |
94dfb5e7 | 963 | if (initial && sched_feat(START_DEBIT)) |
f9c0b095 | 964 | vruntime += sched_vslice(cfs_rq, se); |
aeb73b04 | 965 | |
a2e7a7eb | 966 | /* sleeps up to a single latency don't count. */ |
5ca9880c | 967 | if (!initial) { |
a2e7a7eb | 968 | unsigned long thresh = sysctl_sched_latency; |
a7be37ac | 969 | |
a2e7a7eb MG |
970 | /* |
971 | * Halve their sleep time's effect, to allow | |
972 | * for a gentler effect of sleepers: | |
973 | */ | |
974 | if (sched_feat(GENTLE_FAIR_SLEEPERS)) | |
975 | thresh >>= 1; | |
51e0304c | 976 | |
a2e7a7eb | 977 | vruntime -= thresh; |
aeb73b04 PZ |
978 | } |
979 | ||
b5d9d734 MG |
980 | /* ensure we never gain time by being placed backwards. */ |
981 | vruntime = max_vruntime(se->vruntime, vruntime); | |
982 | ||
67e9fb2a | 983 | se->vruntime = vruntime; |
aeb73b04 PZ |
984 | } |
985 | ||
d3d9dc33 PT |
986 | static void check_enqueue_throttle(struct cfs_rq *cfs_rq); |
987 | ||
bf0f6f24 | 988 | static void |
88ec22d3 | 989 | enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) |
bf0f6f24 | 990 | { |
88ec22d3 PZ |
991 | /* |
992 | * Update the normalized vruntime before updating min_vruntime | |
993 | * through callig update_curr(). | |
994 | */ | |
371fd7e7 | 995 | if (!(flags & ENQUEUE_WAKEUP) || (flags & ENQUEUE_WAKING)) |
88ec22d3 PZ |
996 | se->vruntime += cfs_rq->min_vruntime; |
997 | ||
bf0f6f24 | 998 | /* |
a2a2d680 | 999 | * Update run-time statistics of the 'current'. |
bf0f6f24 | 1000 | */ |
b7cc0896 | 1001 | update_curr(cfs_rq); |
d6b55918 | 1002 | update_cfs_load(cfs_rq, 0); |
a992241d | 1003 | account_entity_enqueue(cfs_rq, se); |
6d5ab293 | 1004 | update_cfs_shares(cfs_rq); |
bf0f6f24 | 1005 | |
88ec22d3 | 1006 | if (flags & ENQUEUE_WAKEUP) { |
aeb73b04 | 1007 | place_entity(cfs_rq, se, 0); |
2396af69 | 1008 | enqueue_sleeper(cfs_rq, se); |
e9acbff6 | 1009 | } |
bf0f6f24 | 1010 | |
d2417e5a | 1011 | update_stats_enqueue(cfs_rq, se); |
ddc97297 | 1012 | check_spread(cfs_rq, se); |
83b699ed SV |
1013 | if (se != cfs_rq->curr) |
1014 | __enqueue_entity(cfs_rq, se); | |
2069dd75 | 1015 | se->on_rq = 1; |
3d4b47b4 | 1016 | |
d3d9dc33 | 1017 | if (cfs_rq->nr_running == 1) { |
3d4b47b4 | 1018 | list_add_leaf_cfs_rq(cfs_rq); |
d3d9dc33 PT |
1019 | check_enqueue_throttle(cfs_rq); |
1020 | } | |
bf0f6f24 IM |
1021 | } |
1022 | ||
2c13c919 | 1023 | static void __clear_buddies_last(struct sched_entity *se) |
2002c695 | 1024 | { |
2c13c919 RR |
1025 | for_each_sched_entity(se) { |
1026 | struct cfs_rq *cfs_rq = cfs_rq_of(se); | |
1027 | if (cfs_rq->last == se) | |
1028 | cfs_rq->last = NULL; | |
1029 | else | |
1030 | break; | |
1031 | } | |
1032 | } | |
2002c695 | 1033 | |
2c13c919 RR |
1034 | static void __clear_buddies_next(struct sched_entity *se) |
1035 | { | |
1036 | for_each_sched_entity(se) { | |
1037 | struct cfs_rq *cfs_rq = cfs_rq_of(se); | |
1038 | if (cfs_rq->next == se) | |
1039 | cfs_rq->next = NULL; | |
1040 | else | |
1041 | break; | |
1042 | } | |
2002c695 PZ |
1043 | } |
1044 | ||
ac53db59 RR |
1045 | static void __clear_buddies_skip(struct sched_entity *se) |
1046 | { | |
1047 | for_each_sched_entity(se) { | |
1048 | struct cfs_rq *cfs_rq = cfs_rq_of(se); | |
1049 | if (cfs_rq->skip == se) | |
1050 | cfs_rq->skip = NULL; | |
1051 | else | |
1052 | break; | |
1053 | } | |
1054 | } | |
1055 | ||
a571bbea PZ |
1056 | static void clear_buddies(struct cfs_rq *cfs_rq, struct sched_entity *se) |
1057 | { | |
2c13c919 RR |
1058 | if (cfs_rq->last == se) |
1059 | __clear_buddies_last(se); | |
1060 | ||
1061 | if (cfs_rq->next == se) | |
1062 | __clear_buddies_next(se); | |
ac53db59 RR |
1063 | |
1064 | if (cfs_rq->skip == se) | |
1065 | __clear_buddies_skip(se); | |
a571bbea PZ |
1066 | } |
1067 | ||
d8b4986d PT |
1068 | static void return_cfs_rq_runtime(struct cfs_rq *cfs_rq); |
1069 | ||
bf0f6f24 | 1070 | static void |
371fd7e7 | 1071 | dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) |
bf0f6f24 | 1072 | { |
a2a2d680 DA |
1073 | /* |
1074 | * Update run-time statistics of the 'current'. | |
1075 | */ | |
1076 | update_curr(cfs_rq); | |
1077 | ||
19b6a2e3 | 1078 | update_stats_dequeue(cfs_rq, se); |
371fd7e7 | 1079 | if (flags & DEQUEUE_SLEEP) { |
67e9fb2a | 1080 | #ifdef CONFIG_SCHEDSTATS |
bf0f6f24 IM |
1081 | if (entity_is_task(se)) { |
1082 | struct task_struct *tsk = task_of(se); | |
1083 | ||
1084 | if (tsk->state & TASK_INTERRUPTIBLE) | |
41acab88 | 1085 | se->statistics.sleep_start = rq_of(cfs_rq)->clock; |
bf0f6f24 | 1086 | if (tsk->state & TASK_UNINTERRUPTIBLE) |
41acab88 | 1087 | se->statistics.block_start = rq_of(cfs_rq)->clock; |
bf0f6f24 | 1088 | } |
db36cc7d | 1089 | #endif |
67e9fb2a PZ |
1090 | } |
1091 | ||
2002c695 | 1092 | clear_buddies(cfs_rq, se); |
4793241b | 1093 | |
83b699ed | 1094 | if (se != cfs_rq->curr) |
30cfdcfc | 1095 | __dequeue_entity(cfs_rq, se); |
2069dd75 | 1096 | se->on_rq = 0; |
d6b55918 | 1097 | update_cfs_load(cfs_rq, 0); |
30cfdcfc | 1098 | account_entity_dequeue(cfs_rq, se); |
88ec22d3 PZ |
1099 | |
1100 | /* | |
1101 | * Normalize the entity after updating the min_vruntime because the | |
1102 | * update can refer to the ->curr item and we need to reflect this | |
1103 | * movement in our normalized position. | |
1104 | */ | |
371fd7e7 | 1105 | if (!(flags & DEQUEUE_SLEEP)) |
88ec22d3 | 1106 | se->vruntime -= cfs_rq->min_vruntime; |
1e876231 | 1107 | |
d8b4986d PT |
1108 | /* return excess runtime on last dequeue */ |
1109 | return_cfs_rq_runtime(cfs_rq); | |
1110 | ||
1e876231 PZ |
1111 | update_min_vruntime(cfs_rq); |
1112 | update_cfs_shares(cfs_rq); | |
bf0f6f24 IM |
1113 | } |
1114 | ||
1115 | /* | |
1116 | * Preempt the current task with a newly woken task if needed: | |
1117 | */ | |
7c92e54f | 1118 | static void |
2e09bf55 | 1119 | check_preempt_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr) |
bf0f6f24 | 1120 | { |
11697830 | 1121 | unsigned long ideal_runtime, delta_exec; |
f4cfb33e WX |
1122 | struct sched_entity *se; |
1123 | s64 delta; | |
11697830 | 1124 | |
6d0f0ebd | 1125 | ideal_runtime = sched_slice(cfs_rq, curr); |
11697830 | 1126 | delta_exec = curr->sum_exec_runtime - curr->prev_sum_exec_runtime; |
a9f3e2b5 | 1127 | if (delta_exec > ideal_runtime) { |
bf0f6f24 | 1128 | resched_task(rq_of(cfs_rq)->curr); |
a9f3e2b5 MG |
1129 | /* |
1130 | * The current task ran long enough, ensure it doesn't get | |
1131 | * re-elected due to buddy favours. | |
1132 | */ | |
1133 | clear_buddies(cfs_rq, curr); | |
f685ceac MG |
1134 | return; |
1135 | } | |
1136 | ||
1137 | /* | |
1138 | * Ensure that a task that missed wakeup preemption by a | |
1139 | * narrow margin doesn't have to wait for a full slice. | |
1140 | * This also mitigates buddy induced latencies under load. | |
1141 | */ | |
f685ceac MG |
1142 | if (delta_exec < sysctl_sched_min_granularity) |
1143 | return; | |
1144 | ||
f4cfb33e WX |
1145 | se = __pick_first_entity(cfs_rq); |
1146 | delta = curr->vruntime - se->vruntime; | |
f685ceac | 1147 | |
f4cfb33e WX |
1148 | if (delta < 0) |
1149 | return; | |
d7d82944 | 1150 | |
f4cfb33e WX |
1151 | if (delta > ideal_runtime) |
1152 | resched_task(rq_of(cfs_rq)->curr); | |
bf0f6f24 IM |
1153 | } |
1154 | ||
83b699ed | 1155 | static void |
8494f412 | 1156 | set_next_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 1157 | { |
83b699ed SV |
1158 | /* 'current' is not kept within the tree. */ |
1159 | if (se->on_rq) { | |
1160 | /* | |
1161 | * Any task has to be enqueued before it get to execute on | |
1162 | * a CPU. So account for the time it spent waiting on the | |
1163 | * runqueue. | |
1164 | */ | |
1165 | update_stats_wait_end(cfs_rq, se); | |
1166 | __dequeue_entity(cfs_rq, se); | |
1167 | } | |
1168 | ||
79303e9e | 1169 | update_stats_curr_start(cfs_rq, se); |
429d43bc | 1170 | cfs_rq->curr = se; |
eba1ed4b IM |
1171 | #ifdef CONFIG_SCHEDSTATS |
1172 | /* | |
1173 | * Track our maximum slice length, if the CPU's load is at | |
1174 | * least twice that of our own weight (i.e. dont track it | |
1175 | * when there are only lesser-weight tasks around): | |
1176 | */ | |
495eca49 | 1177 | if (rq_of(cfs_rq)->load.weight >= 2*se->load.weight) { |
41acab88 | 1178 | se->statistics.slice_max = max(se->statistics.slice_max, |
eba1ed4b IM |
1179 | se->sum_exec_runtime - se->prev_sum_exec_runtime); |
1180 | } | |
1181 | #endif | |
4a55b450 | 1182 | se->prev_sum_exec_runtime = se->sum_exec_runtime; |
bf0f6f24 IM |
1183 | } |
1184 | ||
3f3a4904 PZ |
1185 | static int |
1186 | wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se); | |
1187 | ||
ac53db59 RR |
1188 | /* |
1189 | * Pick the next process, keeping these things in mind, in this order: | |
1190 | * 1) keep things fair between processes/task groups | |
1191 | * 2) pick the "next" process, since someone really wants that to run | |
1192 | * 3) pick the "last" process, for cache locality | |
1193 | * 4) do not run the "skip" process, if something else is available | |
1194 | */ | |
f4b6755f | 1195 | static struct sched_entity *pick_next_entity(struct cfs_rq *cfs_rq) |
aa2ac252 | 1196 | { |
ac53db59 | 1197 | struct sched_entity *se = __pick_first_entity(cfs_rq); |
f685ceac | 1198 | struct sched_entity *left = se; |
f4b6755f | 1199 | |
ac53db59 RR |
1200 | /* |
1201 | * Avoid running the skip buddy, if running something else can | |
1202 | * be done without getting too unfair. | |
1203 | */ | |
1204 | if (cfs_rq->skip == se) { | |
1205 | struct sched_entity *second = __pick_next_entity(se); | |
1206 | if (second && wakeup_preempt_entity(second, left) < 1) | |
1207 | se = second; | |
1208 | } | |
aa2ac252 | 1209 | |
f685ceac MG |
1210 | /* |
1211 | * Prefer last buddy, try to return the CPU to a preempted task. | |
1212 | */ | |
1213 | if (cfs_rq->last && wakeup_preempt_entity(cfs_rq->last, left) < 1) | |
1214 | se = cfs_rq->last; | |
1215 | ||
ac53db59 RR |
1216 | /* |
1217 | * Someone really wants this to run. If it's not unfair, run it. | |
1218 | */ | |
1219 | if (cfs_rq->next && wakeup_preempt_entity(cfs_rq->next, left) < 1) | |
1220 | se = cfs_rq->next; | |
1221 | ||
f685ceac | 1222 | clear_buddies(cfs_rq, se); |
4793241b PZ |
1223 | |
1224 | return se; | |
aa2ac252 PZ |
1225 | } |
1226 | ||
d3d9dc33 PT |
1227 | static void check_cfs_rq_runtime(struct cfs_rq *cfs_rq); |
1228 | ||
ab6cde26 | 1229 | static void put_prev_entity(struct cfs_rq *cfs_rq, struct sched_entity *prev) |
bf0f6f24 IM |
1230 | { |
1231 | /* | |
1232 | * If still on the runqueue then deactivate_task() | |
1233 | * was not called and update_curr() has to be done: | |
1234 | */ | |
1235 | if (prev->on_rq) | |
b7cc0896 | 1236 | update_curr(cfs_rq); |
bf0f6f24 | 1237 | |
d3d9dc33 PT |
1238 | /* throttle cfs_rqs exceeding runtime */ |
1239 | check_cfs_rq_runtime(cfs_rq); | |
1240 | ||
ddc97297 | 1241 | check_spread(cfs_rq, prev); |
30cfdcfc | 1242 | if (prev->on_rq) { |
5870db5b | 1243 | update_stats_wait_start(cfs_rq, prev); |
30cfdcfc DA |
1244 | /* Put 'current' back into the tree. */ |
1245 | __enqueue_entity(cfs_rq, prev); | |
1246 | } | |
429d43bc | 1247 | cfs_rq->curr = NULL; |
bf0f6f24 IM |
1248 | } |
1249 | ||
8f4d37ec PZ |
1250 | static void |
1251 | entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr, int queued) | |
bf0f6f24 | 1252 | { |
bf0f6f24 | 1253 | /* |
30cfdcfc | 1254 | * Update run-time statistics of the 'current'. |
bf0f6f24 | 1255 | */ |
30cfdcfc | 1256 | update_curr(cfs_rq); |
bf0f6f24 | 1257 | |
43365bd7 PT |
1258 | /* |
1259 | * Update share accounting for long-running entities. | |
1260 | */ | |
1261 | update_entity_shares_tick(cfs_rq); | |
1262 | ||
8f4d37ec PZ |
1263 | #ifdef CONFIG_SCHED_HRTICK |
1264 | /* | |
1265 | * queued ticks are scheduled to match the slice, so don't bother | |
1266 | * validating it and just reschedule. | |
1267 | */ | |
983ed7a6 HH |
1268 | if (queued) { |
1269 | resched_task(rq_of(cfs_rq)->curr); | |
1270 | return; | |
1271 | } | |
8f4d37ec PZ |
1272 | /* |
1273 | * don't let the period tick interfere with the hrtick preemption | |
1274 | */ | |
1275 | if (!sched_feat(DOUBLE_TICK) && | |
1276 | hrtimer_active(&rq_of(cfs_rq)->hrtick_timer)) | |
1277 | return; | |
1278 | #endif | |
1279 | ||
2c2efaed | 1280 | if (cfs_rq->nr_running > 1) |
2e09bf55 | 1281 | check_preempt_tick(cfs_rq, curr); |
bf0f6f24 IM |
1282 | } |
1283 | ||
ab84d31e PT |
1284 | |
1285 | /************************************************** | |
1286 | * CFS bandwidth control machinery | |
1287 | */ | |
1288 | ||
1289 | #ifdef CONFIG_CFS_BANDWIDTH | |
1290 | /* | |
1291 | * default period for cfs group bandwidth. | |
1292 | * default: 0.1s, units: nanoseconds | |
1293 | */ | |
1294 | static inline u64 default_cfs_period(void) | |
1295 | { | |
1296 | return 100000000ULL; | |
1297 | } | |
ec12cb7f PT |
1298 | |
1299 | static inline u64 sched_cfs_bandwidth_slice(void) | |
1300 | { | |
1301 | return (u64)sysctl_sched_cfs_bandwidth_slice * NSEC_PER_USEC; | |
1302 | } | |
1303 | ||
a9cf55b2 PT |
1304 | /* |
1305 | * Replenish runtime according to assigned quota and update expiration time. | |
1306 | * We use sched_clock_cpu directly instead of rq->clock to avoid adding | |
1307 | * additional synchronization around rq->lock. | |
1308 | * | |
1309 | * requires cfs_b->lock | |
1310 | */ | |
1311 | static void __refill_cfs_bandwidth_runtime(struct cfs_bandwidth *cfs_b) | |
1312 | { | |
1313 | u64 now; | |
1314 | ||
1315 | if (cfs_b->quota == RUNTIME_INF) | |
1316 | return; | |
1317 | ||
1318 | now = sched_clock_cpu(smp_processor_id()); | |
1319 | cfs_b->runtime = cfs_b->quota; | |
1320 | cfs_b->runtime_expires = now + ktime_to_ns(cfs_b->period); | |
1321 | } | |
1322 | ||
85dac906 PT |
1323 | /* returns 0 on failure to allocate runtime */ |
1324 | static int assign_cfs_rq_runtime(struct cfs_rq *cfs_rq) | |
ec12cb7f PT |
1325 | { |
1326 | struct task_group *tg = cfs_rq->tg; | |
1327 | struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(tg); | |
a9cf55b2 | 1328 | u64 amount = 0, min_amount, expires; |
ec12cb7f PT |
1329 | |
1330 | /* note: this is a positive sum as runtime_remaining <= 0 */ | |
1331 | min_amount = sched_cfs_bandwidth_slice() - cfs_rq->runtime_remaining; | |
1332 | ||
1333 | raw_spin_lock(&cfs_b->lock); | |
1334 | if (cfs_b->quota == RUNTIME_INF) | |
1335 | amount = min_amount; | |
58088ad0 | 1336 | else { |
a9cf55b2 PT |
1337 | /* |
1338 | * If the bandwidth pool has become inactive, then at least one | |
1339 | * period must have elapsed since the last consumption. | |
1340 | * Refresh the global state and ensure bandwidth timer becomes | |
1341 | * active. | |
1342 | */ | |
1343 | if (!cfs_b->timer_active) { | |
1344 | __refill_cfs_bandwidth_runtime(cfs_b); | |
58088ad0 | 1345 | __start_cfs_bandwidth(cfs_b); |
a9cf55b2 | 1346 | } |
58088ad0 PT |
1347 | |
1348 | if (cfs_b->runtime > 0) { | |
1349 | amount = min(cfs_b->runtime, min_amount); | |
1350 | cfs_b->runtime -= amount; | |
1351 | cfs_b->idle = 0; | |
1352 | } | |
ec12cb7f | 1353 | } |
a9cf55b2 | 1354 | expires = cfs_b->runtime_expires; |
ec12cb7f PT |
1355 | raw_spin_unlock(&cfs_b->lock); |
1356 | ||
1357 | cfs_rq->runtime_remaining += amount; | |
a9cf55b2 PT |
1358 | /* |
1359 | * we may have advanced our local expiration to account for allowed | |
1360 | * spread between our sched_clock and the one on which runtime was | |
1361 | * issued. | |
1362 | */ | |
1363 | if ((s64)(expires - cfs_rq->runtime_expires) > 0) | |
1364 | cfs_rq->runtime_expires = expires; | |
85dac906 PT |
1365 | |
1366 | return cfs_rq->runtime_remaining > 0; | |
ec12cb7f PT |
1367 | } |
1368 | ||
a9cf55b2 PT |
1369 | /* |
1370 | * Note: This depends on the synchronization provided by sched_clock and the | |
1371 | * fact that rq->clock snapshots this value. | |
1372 | */ | |
1373 | static void expire_cfs_rq_runtime(struct cfs_rq *cfs_rq) | |
ec12cb7f | 1374 | { |
a9cf55b2 PT |
1375 | struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg); |
1376 | struct rq *rq = rq_of(cfs_rq); | |
1377 | ||
1378 | /* if the deadline is ahead of our clock, nothing to do */ | |
1379 | if (likely((s64)(rq->clock - cfs_rq->runtime_expires) < 0)) | |
ec12cb7f PT |
1380 | return; |
1381 | ||
a9cf55b2 PT |
1382 | if (cfs_rq->runtime_remaining < 0) |
1383 | return; | |
1384 | ||
1385 | /* | |
1386 | * If the local deadline has passed we have to consider the | |
1387 | * possibility that our sched_clock is 'fast' and the global deadline | |
1388 | * has not truly expired. | |
1389 | * | |
1390 | * Fortunately we can check determine whether this the case by checking | |
1391 | * whether the global deadline has advanced. | |
1392 | */ | |
1393 | ||
1394 | if ((s64)(cfs_rq->runtime_expires - cfs_b->runtime_expires) >= 0) { | |
1395 | /* extend local deadline, drift is bounded above by 2 ticks */ | |
1396 | cfs_rq->runtime_expires += TICK_NSEC; | |
1397 | } else { | |
1398 | /* global deadline is ahead, expiration has passed */ | |
1399 | cfs_rq->runtime_remaining = 0; | |
1400 | } | |
1401 | } | |
1402 | ||
1403 | static void __account_cfs_rq_runtime(struct cfs_rq *cfs_rq, | |
1404 | unsigned long delta_exec) | |
1405 | { | |
1406 | /* dock delta_exec before expiring quota (as it could span periods) */ | |
ec12cb7f | 1407 | cfs_rq->runtime_remaining -= delta_exec; |
a9cf55b2 PT |
1408 | expire_cfs_rq_runtime(cfs_rq); |
1409 | ||
1410 | if (likely(cfs_rq->runtime_remaining > 0)) | |
ec12cb7f PT |
1411 | return; |
1412 | ||
85dac906 PT |
1413 | /* |
1414 | * if we're unable to extend our runtime we resched so that the active | |
1415 | * hierarchy can be throttled | |
1416 | */ | |
1417 | if (!assign_cfs_rq_runtime(cfs_rq) && likely(cfs_rq->curr)) | |
1418 | resched_task(rq_of(cfs_rq)->curr); | |
ec12cb7f PT |
1419 | } |
1420 | ||
1421 | static __always_inline void account_cfs_rq_runtime(struct cfs_rq *cfs_rq, | |
1422 | unsigned long delta_exec) | |
1423 | { | |
1424 | if (!cfs_rq->runtime_enabled) | |
1425 | return; | |
1426 | ||
1427 | __account_cfs_rq_runtime(cfs_rq, delta_exec); | |
1428 | } | |
1429 | ||
85dac906 PT |
1430 | static inline int cfs_rq_throttled(struct cfs_rq *cfs_rq) |
1431 | { | |
1432 | return cfs_rq->throttled; | |
1433 | } | |
1434 | ||
64660c86 PT |
1435 | /* check whether cfs_rq, or any parent, is throttled */ |
1436 | static inline int throttled_hierarchy(struct cfs_rq *cfs_rq) | |
1437 | { | |
1438 | return cfs_rq->throttle_count; | |
1439 | } | |
1440 | ||
1441 | /* | |
1442 | * Ensure that neither of the group entities corresponding to src_cpu or | |
1443 | * dest_cpu are members of a throttled hierarchy when performing group | |
1444 | * load-balance operations. | |
1445 | */ | |
1446 | static inline int throttled_lb_pair(struct task_group *tg, | |
1447 | int src_cpu, int dest_cpu) | |
1448 | { | |
1449 | struct cfs_rq *src_cfs_rq, *dest_cfs_rq; | |
1450 | ||
1451 | src_cfs_rq = tg->cfs_rq[src_cpu]; | |
1452 | dest_cfs_rq = tg->cfs_rq[dest_cpu]; | |
1453 | ||
1454 | return throttled_hierarchy(src_cfs_rq) || | |
1455 | throttled_hierarchy(dest_cfs_rq); | |
1456 | } | |
1457 | ||
1458 | /* updated child weight may affect parent so we have to do this bottom up */ | |
1459 | static int tg_unthrottle_up(struct task_group *tg, void *data) | |
1460 | { | |
1461 | struct rq *rq = data; | |
1462 | struct cfs_rq *cfs_rq = tg->cfs_rq[cpu_of(rq)]; | |
1463 | ||
1464 | cfs_rq->throttle_count--; | |
1465 | #ifdef CONFIG_SMP | |
1466 | if (!cfs_rq->throttle_count) { | |
1467 | u64 delta = rq->clock_task - cfs_rq->load_stamp; | |
1468 | ||
1469 | /* leaving throttled state, advance shares averaging windows */ | |
1470 | cfs_rq->load_stamp += delta; | |
1471 | cfs_rq->load_last += delta; | |
1472 | ||
1473 | /* update entity weight now that we are on_rq again */ | |
1474 | update_cfs_shares(cfs_rq); | |
1475 | } | |
1476 | #endif | |
1477 | ||
1478 | return 0; | |
1479 | } | |
1480 | ||
1481 | static int tg_throttle_down(struct task_group *tg, void *data) | |
1482 | { | |
1483 | struct rq *rq = data; | |
1484 | struct cfs_rq *cfs_rq = tg->cfs_rq[cpu_of(rq)]; | |
1485 | ||
1486 | /* group is entering throttled state, record last load */ | |
1487 | if (!cfs_rq->throttle_count) | |
1488 | update_cfs_load(cfs_rq, 0); | |
1489 | cfs_rq->throttle_count++; | |
1490 | ||
1491 | return 0; | |
1492 | } | |
1493 | ||
d3d9dc33 | 1494 | static void throttle_cfs_rq(struct cfs_rq *cfs_rq) |
85dac906 PT |
1495 | { |
1496 | struct rq *rq = rq_of(cfs_rq); | |
1497 | struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg); | |
1498 | struct sched_entity *se; | |
1499 | long task_delta, dequeue = 1; | |
1500 | ||
1501 | se = cfs_rq->tg->se[cpu_of(rq_of(cfs_rq))]; | |
1502 | ||
1503 | /* account load preceding throttle */ | |
64660c86 PT |
1504 | rcu_read_lock(); |
1505 | walk_tg_tree_from(cfs_rq->tg, tg_throttle_down, tg_nop, (void *)rq); | |
1506 | rcu_read_unlock(); | |
85dac906 PT |
1507 | |
1508 | task_delta = cfs_rq->h_nr_running; | |
1509 | for_each_sched_entity(se) { | |
1510 | struct cfs_rq *qcfs_rq = cfs_rq_of(se); | |
1511 | /* throttled entity or throttle-on-deactivate */ | |
1512 | if (!se->on_rq) | |
1513 | break; | |
1514 | ||
1515 | if (dequeue) | |
1516 | dequeue_entity(qcfs_rq, se, DEQUEUE_SLEEP); | |
1517 | qcfs_rq->h_nr_running -= task_delta; | |
1518 | ||
1519 | if (qcfs_rq->load.weight) | |
1520 | dequeue = 0; | |
1521 | } | |
1522 | ||
1523 | if (!se) | |
1524 | rq->nr_running -= task_delta; | |
1525 | ||
1526 | cfs_rq->throttled = 1; | |
e8da1b18 | 1527 | cfs_rq->throttled_timestamp = rq->clock; |
85dac906 PT |
1528 | raw_spin_lock(&cfs_b->lock); |
1529 | list_add_tail_rcu(&cfs_rq->throttled_list, &cfs_b->throttled_cfs_rq); | |
1530 | raw_spin_unlock(&cfs_b->lock); | |
1531 | } | |
1532 | ||
671fd9da PT |
1533 | static void unthrottle_cfs_rq(struct cfs_rq *cfs_rq) |
1534 | { | |
1535 | struct rq *rq = rq_of(cfs_rq); | |
1536 | struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg); | |
1537 | struct sched_entity *se; | |
1538 | int enqueue = 1; | |
1539 | long task_delta; | |
1540 | ||
1541 | se = cfs_rq->tg->se[cpu_of(rq_of(cfs_rq))]; | |
1542 | ||
1543 | cfs_rq->throttled = 0; | |
1544 | raw_spin_lock(&cfs_b->lock); | |
e8da1b18 | 1545 | cfs_b->throttled_time += rq->clock - cfs_rq->throttled_timestamp; |
671fd9da PT |
1546 | list_del_rcu(&cfs_rq->throttled_list); |
1547 | raw_spin_unlock(&cfs_b->lock); | |
e8da1b18 | 1548 | cfs_rq->throttled_timestamp = 0; |
671fd9da | 1549 | |
64660c86 PT |
1550 | update_rq_clock(rq); |
1551 | /* update hierarchical throttle state */ | |
1552 | walk_tg_tree_from(cfs_rq->tg, tg_nop, tg_unthrottle_up, (void *)rq); | |
1553 | ||
671fd9da PT |
1554 | if (!cfs_rq->load.weight) |
1555 | return; | |
1556 | ||
1557 | task_delta = cfs_rq->h_nr_running; | |
1558 | for_each_sched_entity(se) { | |
1559 | if (se->on_rq) | |
1560 | enqueue = 0; | |
1561 | ||
1562 | cfs_rq = cfs_rq_of(se); | |
1563 | if (enqueue) | |
1564 | enqueue_entity(cfs_rq, se, ENQUEUE_WAKEUP); | |
1565 | cfs_rq->h_nr_running += task_delta; | |
1566 | ||
1567 | if (cfs_rq_throttled(cfs_rq)) | |
1568 | break; | |
1569 | } | |
1570 | ||
1571 | if (!se) | |
1572 | rq->nr_running += task_delta; | |
1573 | ||
1574 | /* determine whether we need to wake up potentially idle cpu */ | |
1575 | if (rq->curr == rq->idle && rq->cfs.nr_running) | |
1576 | resched_task(rq->curr); | |
1577 | } | |
1578 | ||
1579 | static u64 distribute_cfs_runtime(struct cfs_bandwidth *cfs_b, | |
1580 | u64 remaining, u64 expires) | |
1581 | { | |
1582 | struct cfs_rq *cfs_rq; | |
1583 | u64 runtime = remaining; | |
1584 | ||
1585 | rcu_read_lock(); | |
1586 | list_for_each_entry_rcu(cfs_rq, &cfs_b->throttled_cfs_rq, | |
1587 | throttled_list) { | |
1588 | struct rq *rq = rq_of(cfs_rq); | |
1589 | ||
1590 | raw_spin_lock(&rq->lock); | |
1591 | if (!cfs_rq_throttled(cfs_rq)) | |
1592 | goto next; | |
1593 | ||
1594 | runtime = -cfs_rq->runtime_remaining + 1; | |
1595 | if (runtime > remaining) | |
1596 | runtime = remaining; | |
1597 | remaining -= runtime; | |
1598 | ||
1599 | cfs_rq->runtime_remaining += runtime; | |
1600 | cfs_rq->runtime_expires = expires; | |
1601 | ||
1602 | /* we check whether we're throttled above */ | |
1603 | if (cfs_rq->runtime_remaining > 0) | |
1604 | unthrottle_cfs_rq(cfs_rq); | |
1605 | ||
1606 | next: | |
1607 | raw_spin_unlock(&rq->lock); | |
1608 | ||
1609 | if (!remaining) | |
1610 | break; | |
1611 | } | |
1612 | rcu_read_unlock(); | |
1613 | ||
1614 | return remaining; | |
1615 | } | |
1616 | ||
58088ad0 PT |
1617 | /* |
1618 | * Responsible for refilling a task_group's bandwidth and unthrottling its | |
1619 | * cfs_rqs as appropriate. If there has been no activity within the last | |
1620 | * period the timer is deactivated until scheduling resumes; cfs_b->idle is | |
1621 | * used to track this state. | |
1622 | */ | |
1623 | static int do_sched_cfs_period_timer(struct cfs_bandwidth *cfs_b, int overrun) | |
1624 | { | |
671fd9da PT |
1625 | u64 runtime, runtime_expires; |
1626 | int idle = 1, throttled; | |
58088ad0 PT |
1627 | |
1628 | raw_spin_lock(&cfs_b->lock); | |
1629 | /* no need to continue the timer with no bandwidth constraint */ | |
1630 | if (cfs_b->quota == RUNTIME_INF) | |
1631 | goto out_unlock; | |
1632 | ||
671fd9da PT |
1633 | throttled = !list_empty(&cfs_b->throttled_cfs_rq); |
1634 | /* idle depends on !throttled (for the case of a large deficit) */ | |
1635 | idle = cfs_b->idle && !throttled; | |
e8da1b18 | 1636 | cfs_b->nr_periods += overrun; |
671fd9da | 1637 | |
a9cf55b2 PT |
1638 | /* if we're going inactive then everything else can be deferred */ |
1639 | if (idle) | |
1640 | goto out_unlock; | |
1641 | ||
1642 | __refill_cfs_bandwidth_runtime(cfs_b); | |
1643 | ||
671fd9da PT |
1644 | if (!throttled) { |
1645 | /* mark as potentially idle for the upcoming period */ | |
1646 | cfs_b->idle = 1; | |
1647 | goto out_unlock; | |
1648 | } | |
1649 | ||
e8da1b18 NR |
1650 | /* account preceding periods in which throttling occurred */ |
1651 | cfs_b->nr_throttled += overrun; | |
1652 | ||
671fd9da PT |
1653 | /* |
1654 | * There are throttled entities so we must first use the new bandwidth | |
1655 | * to unthrottle them before making it generally available. This | |
1656 | * ensures that all existing debts will be paid before a new cfs_rq is | |
1657 | * allowed to run. | |
1658 | */ | |
1659 | runtime = cfs_b->runtime; | |
1660 | runtime_expires = cfs_b->runtime_expires; | |
1661 | cfs_b->runtime = 0; | |
1662 | ||
1663 | /* | |
1664 | * This check is repeated as we are holding onto the new bandwidth | |
1665 | * while we unthrottle. This can potentially race with an unthrottled | |
1666 | * group trying to acquire new bandwidth from the global pool. | |
1667 | */ | |
1668 | while (throttled && runtime > 0) { | |
1669 | raw_spin_unlock(&cfs_b->lock); | |
1670 | /* we can't nest cfs_b->lock while distributing bandwidth */ | |
1671 | runtime = distribute_cfs_runtime(cfs_b, runtime, | |
1672 | runtime_expires); | |
1673 | raw_spin_lock(&cfs_b->lock); | |
1674 | ||
1675 | throttled = !list_empty(&cfs_b->throttled_cfs_rq); | |
1676 | } | |
58088ad0 | 1677 | |
671fd9da PT |
1678 | /* return (any) remaining runtime */ |
1679 | cfs_b->runtime = runtime; | |
1680 | /* | |
1681 | * While we are ensured activity in the period following an | |
1682 | * unthrottle, this also covers the case in which the new bandwidth is | |
1683 | * insufficient to cover the existing bandwidth deficit. (Forcing the | |
1684 | * timer to remain active while there are any throttled entities.) | |
1685 | */ | |
1686 | cfs_b->idle = 0; | |
58088ad0 PT |
1687 | out_unlock: |
1688 | if (idle) | |
1689 | cfs_b->timer_active = 0; | |
1690 | raw_spin_unlock(&cfs_b->lock); | |
1691 | ||
1692 | return idle; | |
1693 | } | |
d3d9dc33 | 1694 | |
d8b4986d PT |
1695 | /* a cfs_rq won't donate quota below this amount */ |
1696 | static const u64 min_cfs_rq_runtime = 1 * NSEC_PER_MSEC; | |
1697 | /* minimum remaining period time to redistribute slack quota */ | |
1698 | static const u64 min_bandwidth_expiration = 2 * NSEC_PER_MSEC; | |
1699 | /* how long we wait to gather additional slack before distributing */ | |
1700 | static const u64 cfs_bandwidth_slack_period = 5 * NSEC_PER_MSEC; | |
1701 | ||
1702 | /* are we near the end of the current quota period? */ | |
1703 | static int runtime_refresh_within(struct cfs_bandwidth *cfs_b, u64 min_expire) | |
1704 | { | |
1705 | struct hrtimer *refresh_timer = &cfs_b->period_timer; | |
1706 | u64 remaining; | |
1707 | ||
1708 | /* if the call-back is running a quota refresh is already occurring */ | |
1709 | if (hrtimer_callback_running(refresh_timer)) | |
1710 | return 1; | |
1711 | ||
1712 | /* is a quota refresh about to occur? */ | |
1713 | remaining = ktime_to_ns(hrtimer_expires_remaining(refresh_timer)); | |
1714 | if (remaining < min_expire) | |
1715 | return 1; | |
1716 | ||
1717 | return 0; | |
1718 | } | |
1719 | ||
1720 | static void start_cfs_slack_bandwidth(struct cfs_bandwidth *cfs_b) | |
1721 | { | |
1722 | u64 min_left = cfs_bandwidth_slack_period + min_bandwidth_expiration; | |
1723 | ||
1724 | /* if there's a quota refresh soon don't bother with slack */ | |
1725 | if (runtime_refresh_within(cfs_b, min_left)) | |
1726 | return; | |
1727 | ||
1728 | start_bandwidth_timer(&cfs_b->slack_timer, | |
1729 | ns_to_ktime(cfs_bandwidth_slack_period)); | |
1730 | } | |
1731 | ||
1732 | /* we know any runtime found here is valid as update_curr() precedes return */ | |
1733 | static void __return_cfs_rq_runtime(struct cfs_rq *cfs_rq) | |
1734 | { | |
1735 | struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg); | |
1736 | s64 slack_runtime = cfs_rq->runtime_remaining - min_cfs_rq_runtime; | |
1737 | ||
1738 | if (slack_runtime <= 0) | |
1739 | return; | |
1740 | ||
1741 | raw_spin_lock(&cfs_b->lock); | |
1742 | if (cfs_b->quota != RUNTIME_INF && | |
1743 | cfs_rq->runtime_expires == cfs_b->runtime_expires) { | |
1744 | cfs_b->runtime += slack_runtime; | |
1745 | ||
1746 | /* we are under rq->lock, defer unthrottling using a timer */ | |
1747 | if (cfs_b->runtime > sched_cfs_bandwidth_slice() && | |
1748 | !list_empty(&cfs_b->throttled_cfs_rq)) | |
1749 | start_cfs_slack_bandwidth(cfs_b); | |
1750 | } | |
1751 | raw_spin_unlock(&cfs_b->lock); | |
1752 | ||
1753 | /* even if it's not valid for return we don't want to try again */ | |
1754 | cfs_rq->runtime_remaining -= slack_runtime; | |
1755 | } | |
1756 | ||
1757 | static __always_inline void return_cfs_rq_runtime(struct cfs_rq *cfs_rq) | |
1758 | { | |
fccfdc6f | 1759 | if (!cfs_rq->runtime_enabled || cfs_rq->nr_running) |
d8b4986d PT |
1760 | return; |
1761 | ||
1762 | __return_cfs_rq_runtime(cfs_rq); | |
1763 | } | |
1764 | ||
1765 | /* | |
1766 | * This is done with a timer (instead of inline with bandwidth return) since | |
1767 | * it's necessary to juggle rq->locks to unthrottle their respective cfs_rqs. | |
1768 | */ | |
1769 | static void do_sched_cfs_slack_timer(struct cfs_bandwidth *cfs_b) | |
1770 | { | |
1771 | u64 runtime = 0, slice = sched_cfs_bandwidth_slice(); | |
1772 | u64 expires; | |
1773 | ||
1774 | /* confirm we're still not at a refresh boundary */ | |
1775 | if (runtime_refresh_within(cfs_b, min_bandwidth_expiration)) | |
1776 | return; | |
1777 | ||
1778 | raw_spin_lock(&cfs_b->lock); | |
1779 | if (cfs_b->quota != RUNTIME_INF && cfs_b->runtime > slice) { | |
1780 | runtime = cfs_b->runtime; | |
1781 | cfs_b->runtime = 0; | |
1782 | } | |
1783 | expires = cfs_b->runtime_expires; | |
1784 | raw_spin_unlock(&cfs_b->lock); | |
1785 | ||
1786 | if (!runtime) | |
1787 | return; | |
1788 | ||
1789 | runtime = distribute_cfs_runtime(cfs_b, runtime, expires); | |
1790 | ||
1791 | raw_spin_lock(&cfs_b->lock); | |
1792 | if (expires == cfs_b->runtime_expires) | |
1793 | cfs_b->runtime = runtime; | |
1794 | raw_spin_unlock(&cfs_b->lock); | |
1795 | } | |
1796 | ||
d3d9dc33 PT |
1797 | /* |
1798 | * When a group wakes up we want to make sure that its quota is not already | |
1799 | * expired/exceeded, otherwise it may be allowed to steal additional ticks of | |
1800 | * runtime as update_curr() throttling can not not trigger until it's on-rq. | |
1801 | */ | |
1802 | static void check_enqueue_throttle(struct cfs_rq *cfs_rq) | |
1803 | { | |
1804 | /* an active group must be handled by the update_curr()->put() path */ | |
1805 | if (!cfs_rq->runtime_enabled || cfs_rq->curr) | |
1806 | return; | |
1807 | ||
1808 | /* ensure the group is not already throttled */ | |
1809 | if (cfs_rq_throttled(cfs_rq)) | |
1810 | return; | |
1811 | ||
1812 | /* update runtime allocation */ | |
1813 | account_cfs_rq_runtime(cfs_rq, 0); | |
1814 | if (cfs_rq->runtime_remaining <= 0) | |
1815 | throttle_cfs_rq(cfs_rq); | |
1816 | } | |
1817 | ||
1818 | /* conditionally throttle active cfs_rq's from put_prev_entity() */ | |
1819 | static void check_cfs_rq_runtime(struct cfs_rq *cfs_rq) | |
1820 | { | |
1821 | if (likely(!cfs_rq->runtime_enabled || cfs_rq->runtime_remaining > 0)) | |
1822 | return; | |
1823 | ||
1824 | /* | |
1825 | * it's possible for a throttled entity to be forced into a running | |
1826 | * state (e.g. set_curr_task), in this case we're finished. | |
1827 | */ | |
1828 | if (cfs_rq_throttled(cfs_rq)) | |
1829 | return; | |
1830 | ||
1831 | throttle_cfs_rq(cfs_rq); | |
1832 | } | |
ec12cb7f PT |
1833 | #else |
1834 | static void account_cfs_rq_runtime(struct cfs_rq *cfs_rq, | |
1835 | unsigned long delta_exec) {} | |
d3d9dc33 PT |
1836 | static void check_cfs_rq_runtime(struct cfs_rq *cfs_rq) {} |
1837 | static void check_enqueue_throttle(struct cfs_rq *cfs_rq) {} | |
d8b4986d | 1838 | static void return_cfs_rq_runtime(struct cfs_rq *cfs_rq) {} |
85dac906 PT |
1839 | |
1840 | static inline int cfs_rq_throttled(struct cfs_rq *cfs_rq) | |
1841 | { | |
1842 | return 0; | |
1843 | } | |
64660c86 PT |
1844 | |
1845 | static inline int throttled_hierarchy(struct cfs_rq *cfs_rq) | |
1846 | { | |
1847 | return 0; | |
1848 | } | |
1849 | ||
1850 | static inline int throttled_lb_pair(struct task_group *tg, | |
1851 | int src_cpu, int dest_cpu) | |
1852 | { | |
1853 | return 0; | |
1854 | } | |
ab84d31e PT |
1855 | #endif |
1856 | ||
bf0f6f24 IM |
1857 | /************************************************** |
1858 | * CFS operations on tasks: | |
1859 | */ | |
1860 | ||
8f4d37ec PZ |
1861 | #ifdef CONFIG_SCHED_HRTICK |
1862 | static void hrtick_start_fair(struct rq *rq, struct task_struct *p) | |
1863 | { | |
8f4d37ec PZ |
1864 | struct sched_entity *se = &p->se; |
1865 | struct cfs_rq *cfs_rq = cfs_rq_of(se); | |
1866 | ||
1867 | WARN_ON(task_rq(p) != rq); | |
1868 | ||
1869 | if (hrtick_enabled(rq) && cfs_rq->nr_running > 1) { | |
1870 | u64 slice = sched_slice(cfs_rq, se); | |
1871 | u64 ran = se->sum_exec_runtime - se->prev_sum_exec_runtime; | |
1872 | s64 delta = slice - ran; | |
1873 | ||
1874 | if (delta < 0) { | |
1875 | if (rq->curr == p) | |
1876 | resched_task(p); | |
1877 | return; | |
1878 | } | |
1879 | ||
1880 | /* | |
1881 | * Don't schedule slices shorter than 10000ns, that just | |
1882 | * doesn't make sense. Rely on vruntime for fairness. | |
1883 | */ | |
31656519 | 1884 | if (rq->curr != p) |
157124c1 | 1885 | delta = max_t(s64, 10000LL, delta); |
8f4d37ec | 1886 | |
31656519 | 1887 | hrtick_start(rq, delta); |
8f4d37ec PZ |
1888 | } |
1889 | } | |
a4c2f00f PZ |
1890 | |
1891 | /* | |
1892 | * called from enqueue/dequeue and updates the hrtick when the | |
1893 | * current task is from our class and nr_running is low enough | |
1894 | * to matter. | |
1895 | */ | |
1896 | static void hrtick_update(struct rq *rq) | |
1897 | { | |
1898 | struct task_struct *curr = rq->curr; | |
1899 | ||
1900 | if (curr->sched_class != &fair_sched_class) | |
1901 | return; | |
1902 | ||
1903 | if (cfs_rq_of(&curr->se)->nr_running < sched_nr_latency) | |
1904 | hrtick_start_fair(rq, curr); | |
1905 | } | |
55e12e5e | 1906 | #else /* !CONFIG_SCHED_HRTICK */ |
8f4d37ec PZ |
1907 | static inline void |
1908 | hrtick_start_fair(struct rq *rq, struct task_struct *p) | |
1909 | { | |
1910 | } | |
a4c2f00f PZ |
1911 | |
1912 | static inline void hrtick_update(struct rq *rq) | |
1913 | { | |
1914 | } | |
8f4d37ec PZ |
1915 | #endif |
1916 | ||
bf0f6f24 IM |
1917 | /* |
1918 | * The enqueue_task method is called before nr_running is | |
1919 | * increased. Here we update the fair scheduling stats and | |
1920 | * then put the task into the rbtree: | |
1921 | */ | |
ea87bb78 | 1922 | static void |
371fd7e7 | 1923 | enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags) |
bf0f6f24 IM |
1924 | { |
1925 | struct cfs_rq *cfs_rq; | |
62fb1851 | 1926 | struct sched_entity *se = &p->se; |
bf0f6f24 IM |
1927 | |
1928 | for_each_sched_entity(se) { | |
62fb1851 | 1929 | if (se->on_rq) |
bf0f6f24 IM |
1930 | break; |
1931 | cfs_rq = cfs_rq_of(se); | |
88ec22d3 | 1932 | enqueue_entity(cfs_rq, se, flags); |
85dac906 PT |
1933 | |
1934 | /* | |
1935 | * end evaluation on encountering a throttled cfs_rq | |
1936 | * | |
1937 | * note: in the case of encountering a throttled cfs_rq we will | |
1938 | * post the final h_nr_running increment below. | |
1939 | */ | |
1940 | if (cfs_rq_throttled(cfs_rq)) | |
1941 | break; | |
953bfcd1 | 1942 | cfs_rq->h_nr_running++; |
85dac906 | 1943 | |
88ec22d3 | 1944 | flags = ENQUEUE_WAKEUP; |
bf0f6f24 | 1945 | } |
8f4d37ec | 1946 | |
2069dd75 | 1947 | for_each_sched_entity(se) { |
0f317143 | 1948 | cfs_rq = cfs_rq_of(se); |
953bfcd1 | 1949 | cfs_rq->h_nr_running++; |
2069dd75 | 1950 | |
85dac906 PT |
1951 | if (cfs_rq_throttled(cfs_rq)) |
1952 | break; | |
1953 | ||
d6b55918 | 1954 | update_cfs_load(cfs_rq, 0); |
6d5ab293 | 1955 | update_cfs_shares(cfs_rq); |
2069dd75 PZ |
1956 | } |
1957 | ||
85dac906 PT |
1958 | if (!se) |
1959 | inc_nr_running(rq); | |
a4c2f00f | 1960 | hrtick_update(rq); |
bf0f6f24 IM |
1961 | } |
1962 | ||
2f36825b VP |
1963 | static void set_next_buddy(struct sched_entity *se); |
1964 | ||
bf0f6f24 IM |
1965 | /* |
1966 | * The dequeue_task method is called before nr_running is | |
1967 | * decreased. We remove the task from the rbtree and | |
1968 | * update the fair scheduling stats: | |
1969 | */ | |
371fd7e7 | 1970 | static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags) |
bf0f6f24 IM |
1971 | { |
1972 | struct cfs_rq *cfs_rq; | |
62fb1851 | 1973 | struct sched_entity *se = &p->se; |
2f36825b | 1974 | int task_sleep = flags & DEQUEUE_SLEEP; |
bf0f6f24 IM |
1975 | |
1976 | for_each_sched_entity(se) { | |
1977 | cfs_rq = cfs_rq_of(se); | |
371fd7e7 | 1978 | dequeue_entity(cfs_rq, se, flags); |
85dac906 PT |
1979 | |
1980 | /* | |
1981 | * end evaluation on encountering a throttled cfs_rq | |
1982 | * | |
1983 | * note: in the case of encountering a throttled cfs_rq we will | |
1984 | * post the final h_nr_running decrement below. | |
1985 | */ | |
1986 | if (cfs_rq_throttled(cfs_rq)) | |
1987 | break; | |
953bfcd1 | 1988 | cfs_rq->h_nr_running--; |
2069dd75 | 1989 | |
bf0f6f24 | 1990 | /* Don't dequeue parent if it has other entities besides us */ |
2f36825b VP |
1991 | if (cfs_rq->load.weight) { |
1992 | /* | |
1993 | * Bias pick_next to pick a task from this cfs_rq, as | |
1994 | * p is sleeping when it is within its sched_slice. | |
1995 | */ | |
1996 | if (task_sleep && parent_entity(se)) | |
1997 | set_next_buddy(parent_entity(se)); | |
9598c82d PT |
1998 | |
1999 | /* avoid re-evaluating load for this entity */ | |
2000 | se = parent_entity(se); | |
bf0f6f24 | 2001 | break; |
2f36825b | 2002 | } |
371fd7e7 | 2003 | flags |= DEQUEUE_SLEEP; |
bf0f6f24 | 2004 | } |
8f4d37ec | 2005 | |
2069dd75 | 2006 | for_each_sched_entity(se) { |
0f317143 | 2007 | cfs_rq = cfs_rq_of(se); |
953bfcd1 | 2008 | cfs_rq->h_nr_running--; |
2069dd75 | 2009 | |
85dac906 PT |
2010 | if (cfs_rq_throttled(cfs_rq)) |
2011 | break; | |
2012 | ||
d6b55918 | 2013 | update_cfs_load(cfs_rq, 0); |
6d5ab293 | 2014 | update_cfs_shares(cfs_rq); |
2069dd75 PZ |
2015 | } |
2016 | ||
85dac906 PT |
2017 | if (!se) |
2018 | dec_nr_running(rq); | |
a4c2f00f | 2019 | hrtick_update(rq); |
bf0f6f24 IM |
2020 | } |
2021 | ||
e7693a36 | 2022 | #ifdef CONFIG_SMP |
098fb9db | 2023 | |
74f8e4b2 | 2024 | static void task_waking_fair(struct task_struct *p) |
88ec22d3 PZ |
2025 | { |
2026 | struct sched_entity *se = &p->se; | |
2027 | struct cfs_rq *cfs_rq = cfs_rq_of(se); | |
3fe1698b PZ |
2028 | u64 min_vruntime; |
2029 | ||
2030 | #ifndef CONFIG_64BIT | |
2031 | u64 min_vruntime_copy; | |
88ec22d3 | 2032 | |
3fe1698b PZ |
2033 | do { |
2034 | min_vruntime_copy = cfs_rq->min_vruntime_copy; | |
2035 | smp_rmb(); | |
2036 | min_vruntime = cfs_rq->min_vruntime; | |
2037 | } while (min_vruntime != min_vruntime_copy); | |
2038 | #else | |
2039 | min_vruntime = cfs_rq->min_vruntime; | |
2040 | #endif | |
88ec22d3 | 2041 | |
3fe1698b | 2042 | se->vruntime -= min_vruntime; |
88ec22d3 PZ |
2043 | } |
2044 | ||
bb3469ac | 2045 | #ifdef CONFIG_FAIR_GROUP_SCHED |
f5bfb7d9 PZ |
2046 | /* |
2047 | * effective_load() calculates the load change as seen from the root_task_group | |
2048 | * | |
2049 | * Adding load to a group doesn't make a group heavier, but can cause movement | |
2050 | * of group shares between cpus. Assuming the shares were perfectly aligned one | |
2051 | * can calculate the shift in shares. | |
cf5f0acf PZ |
2052 | * |
2053 | * Calculate the effective load difference if @wl is added (subtracted) to @tg | |
2054 | * on this @cpu and results in a total addition (subtraction) of @wg to the | |
2055 | * total group weight. | |
2056 | * | |
2057 | * Given a runqueue weight distribution (rw_i) we can compute a shares | |
2058 | * distribution (s_i) using: | |
2059 | * | |
2060 | * s_i = rw_i / \Sum rw_j (1) | |
2061 | * | |
2062 | * Suppose we have 4 CPUs and our @tg is a direct child of the root group and | |
2063 | * has 7 equal weight tasks, distributed as below (rw_i), with the resulting | |
2064 | * shares distribution (s_i): | |
2065 | * | |
2066 | * rw_i = { 2, 4, 1, 0 } | |
2067 | * s_i = { 2/7, 4/7, 1/7, 0 } | |
2068 | * | |
2069 | * As per wake_affine() we're interested in the load of two CPUs (the CPU the | |
2070 | * task used to run on and the CPU the waker is running on), we need to | |
2071 | * compute the effect of waking a task on either CPU and, in case of a sync | |
2072 | * wakeup, compute the effect of the current task going to sleep. | |
2073 | * | |
2074 | * So for a change of @wl to the local @cpu with an overall group weight change | |
2075 | * of @wl we can compute the new shares distribution (s'_i) using: | |
2076 | * | |
2077 | * s'_i = (rw_i + @wl) / (@wg + \Sum rw_j) (2) | |
2078 | * | |
2079 | * Suppose we're interested in CPUs 0 and 1, and want to compute the load | |
2080 | * differences in waking a task to CPU 0. The additional task changes the | |
2081 | * weight and shares distributions like: | |
2082 | * | |
2083 | * rw'_i = { 3, 4, 1, 0 } | |
2084 | * s'_i = { 3/8, 4/8, 1/8, 0 } | |
2085 | * | |
2086 | * We can then compute the difference in effective weight by using: | |
2087 | * | |
2088 | * dw_i = S * (s'_i - s_i) (3) | |
2089 | * | |
2090 | * Where 'S' is the group weight as seen by its parent. | |
2091 | * | |
2092 | * Therefore the effective change in loads on CPU 0 would be 5/56 (3/8 - 2/7) | |
2093 | * times the weight of the group. The effect on CPU 1 would be -4/56 (4/8 - | |
2094 | * 4/7) times the weight of the group. | |
f5bfb7d9 | 2095 | */ |
2069dd75 | 2096 | static long effective_load(struct task_group *tg, int cpu, long wl, long wg) |
bb3469ac | 2097 | { |
4be9daaa | 2098 | struct sched_entity *se = tg->se[cpu]; |
f1d239f7 | 2099 | |
cf5f0acf | 2100 | if (!tg->parent) /* the trivial, non-cgroup case */ |
f1d239f7 PZ |
2101 | return wl; |
2102 | ||
4be9daaa | 2103 | for_each_sched_entity(se) { |
cf5f0acf | 2104 | long w, W; |
4be9daaa | 2105 | |
977dda7c | 2106 | tg = se->my_q->tg; |
bb3469ac | 2107 | |
cf5f0acf PZ |
2108 | /* |
2109 | * W = @wg + \Sum rw_j | |
2110 | */ | |
2111 | W = wg + calc_tg_weight(tg, se->my_q); | |
4be9daaa | 2112 | |
cf5f0acf PZ |
2113 | /* |
2114 | * w = rw_i + @wl | |
2115 | */ | |
2116 | w = se->my_q->load.weight + wl; | |
940959e9 | 2117 | |
cf5f0acf PZ |
2118 | /* |
2119 | * wl = S * s'_i; see (2) | |
2120 | */ | |
2121 | if (W > 0 && w < W) | |
2122 | wl = (w * tg->shares) / W; | |
977dda7c PT |
2123 | else |
2124 | wl = tg->shares; | |
940959e9 | 2125 | |
cf5f0acf PZ |
2126 | /* |
2127 | * Per the above, wl is the new se->load.weight value; since | |
2128 | * those are clipped to [MIN_SHARES, ...) do so now. See | |
2129 | * calc_cfs_shares(). | |
2130 | */ | |
977dda7c PT |
2131 | if (wl < MIN_SHARES) |
2132 | wl = MIN_SHARES; | |
cf5f0acf PZ |
2133 | |
2134 | /* | |
2135 | * wl = dw_i = S * (s'_i - s_i); see (3) | |
2136 | */ | |
977dda7c | 2137 | wl -= se->load.weight; |
cf5f0acf PZ |
2138 | |
2139 | /* | |
2140 | * Recursively apply this logic to all parent groups to compute | |
2141 | * the final effective load change on the root group. Since | |
2142 | * only the @tg group gets extra weight, all parent groups can | |
2143 | * only redistribute existing shares. @wl is the shift in shares | |
2144 | * resulting from this level per the above. | |
2145 | */ | |
4be9daaa | 2146 | wg = 0; |
4be9daaa | 2147 | } |
bb3469ac | 2148 | |
4be9daaa | 2149 | return wl; |
bb3469ac PZ |
2150 | } |
2151 | #else | |
4be9daaa | 2152 | |
83378269 PZ |
2153 | static inline unsigned long effective_load(struct task_group *tg, int cpu, |
2154 | unsigned long wl, unsigned long wg) | |
4be9daaa | 2155 | { |
83378269 | 2156 | return wl; |
bb3469ac | 2157 | } |
4be9daaa | 2158 | |
bb3469ac PZ |
2159 | #endif |
2160 | ||
c88d5910 | 2161 | static int wake_affine(struct sched_domain *sd, struct task_struct *p, int sync) |
098fb9db | 2162 | { |
e37b6a7b | 2163 | s64 this_load, load; |
c88d5910 | 2164 | int idx, this_cpu, prev_cpu; |
098fb9db | 2165 | unsigned long tl_per_task; |
c88d5910 | 2166 | struct task_group *tg; |
83378269 | 2167 | unsigned long weight; |
b3137bc8 | 2168 | int balanced; |
098fb9db | 2169 | |
c88d5910 PZ |
2170 | idx = sd->wake_idx; |
2171 | this_cpu = smp_processor_id(); | |
2172 | prev_cpu = task_cpu(p); | |
2173 | load = source_load(prev_cpu, idx); | |
2174 | this_load = target_load(this_cpu, idx); | |
098fb9db | 2175 | |
b3137bc8 MG |
2176 | /* |
2177 | * If sync wakeup then subtract the (maximum possible) | |
2178 | * effect of the currently running task from the load | |
2179 | * of the current CPU: | |
2180 | */ | |
83378269 PZ |
2181 | if (sync) { |
2182 | tg = task_group(current); | |
2183 | weight = current->se.load.weight; | |
2184 | ||
c88d5910 | 2185 | this_load += effective_load(tg, this_cpu, -weight, -weight); |
83378269 PZ |
2186 | load += effective_load(tg, prev_cpu, 0, -weight); |
2187 | } | |
b3137bc8 | 2188 | |
83378269 PZ |
2189 | tg = task_group(p); |
2190 | weight = p->se.load.weight; | |
b3137bc8 | 2191 | |
71a29aa7 PZ |
2192 | /* |
2193 | * In low-load situations, where prev_cpu is idle and this_cpu is idle | |
c88d5910 PZ |
2194 | * due to the sync cause above having dropped this_load to 0, we'll |
2195 | * always have an imbalance, but there's really nothing you can do | |
2196 | * about that, so that's good too. | |
71a29aa7 PZ |
2197 | * |
2198 | * Otherwise check if either cpus are near enough in load to allow this | |
2199 | * task to be woken on this_cpu. | |
2200 | */ | |
e37b6a7b PT |
2201 | if (this_load > 0) { |
2202 | s64 this_eff_load, prev_eff_load; | |
e51fd5e2 PZ |
2203 | |
2204 | this_eff_load = 100; | |
2205 | this_eff_load *= power_of(prev_cpu); | |
2206 | this_eff_load *= this_load + | |
2207 | effective_load(tg, this_cpu, weight, weight); | |
2208 | ||
2209 | prev_eff_load = 100 + (sd->imbalance_pct - 100) / 2; | |
2210 | prev_eff_load *= power_of(this_cpu); | |
2211 | prev_eff_load *= load + effective_load(tg, prev_cpu, 0, weight); | |
2212 | ||
2213 | balanced = this_eff_load <= prev_eff_load; | |
2214 | } else | |
2215 | balanced = true; | |
b3137bc8 | 2216 | |
098fb9db | 2217 | /* |
4ae7d5ce IM |
2218 | * If the currently running task will sleep within |
2219 | * a reasonable amount of time then attract this newly | |
2220 | * woken task: | |
098fb9db | 2221 | */ |
2fb7635c PZ |
2222 | if (sync && balanced) |
2223 | return 1; | |
098fb9db | 2224 | |
41acab88 | 2225 | schedstat_inc(p, se.statistics.nr_wakeups_affine_attempts); |
098fb9db IM |
2226 | tl_per_task = cpu_avg_load_per_task(this_cpu); |
2227 | ||
c88d5910 PZ |
2228 | if (balanced || |
2229 | (this_load <= load && | |
2230 | this_load + target_load(prev_cpu, idx) <= tl_per_task)) { | |
098fb9db IM |
2231 | /* |
2232 | * This domain has SD_WAKE_AFFINE and | |
2233 | * p is cache cold in this domain, and | |
2234 | * there is no bad imbalance. | |
2235 | */ | |
c88d5910 | 2236 | schedstat_inc(sd, ttwu_move_affine); |
41acab88 | 2237 | schedstat_inc(p, se.statistics.nr_wakeups_affine); |
098fb9db IM |
2238 | |
2239 | return 1; | |
2240 | } | |
2241 | return 0; | |
2242 | } | |
2243 | ||
aaee1203 PZ |
2244 | /* |
2245 | * find_idlest_group finds and returns the least busy CPU group within the | |
2246 | * domain. | |
2247 | */ | |
2248 | static struct sched_group * | |
78e7ed53 | 2249 | find_idlest_group(struct sched_domain *sd, struct task_struct *p, |
5158f4e4 | 2250 | int this_cpu, int load_idx) |
e7693a36 | 2251 | { |
b3bd3de6 | 2252 | struct sched_group *idlest = NULL, *group = sd->groups; |
aaee1203 | 2253 | unsigned long min_load = ULONG_MAX, this_load = 0; |
aaee1203 | 2254 | int imbalance = 100 + (sd->imbalance_pct-100)/2; |
e7693a36 | 2255 | |
aaee1203 PZ |
2256 | do { |
2257 | unsigned long load, avg_load; | |
2258 | int local_group; | |
2259 | int i; | |
e7693a36 | 2260 | |
aaee1203 PZ |
2261 | /* Skip over this group if it has no CPUs allowed */ |
2262 | if (!cpumask_intersects(sched_group_cpus(group), | |
fa17b507 | 2263 | tsk_cpus_allowed(p))) |
aaee1203 PZ |
2264 | continue; |
2265 | ||
2266 | local_group = cpumask_test_cpu(this_cpu, | |
2267 | sched_group_cpus(group)); | |
2268 | ||
2269 | /* Tally up the load of all CPUs in the group */ | |
2270 | avg_load = 0; | |
2271 | ||
2272 | for_each_cpu(i, sched_group_cpus(group)) { | |
2273 | /* Bias balancing toward cpus of our domain */ | |
2274 | if (local_group) | |
2275 | load = source_load(i, load_idx); | |
2276 | else | |
2277 | load = target_load(i, load_idx); | |
2278 | ||
2279 | avg_load += load; | |
2280 | } | |
2281 | ||
2282 | /* Adjust by relative CPU power of the group */ | |
9c3f75cb | 2283 | avg_load = (avg_load * SCHED_POWER_SCALE) / group->sgp->power; |
aaee1203 PZ |
2284 | |
2285 | if (local_group) { | |
2286 | this_load = avg_load; | |
aaee1203 PZ |
2287 | } else if (avg_load < min_load) { |
2288 | min_load = avg_load; | |
2289 | idlest = group; | |
2290 | } | |
2291 | } while (group = group->next, group != sd->groups); | |
2292 | ||
2293 | if (!idlest || 100*this_load < imbalance*min_load) | |
2294 | return NULL; | |
2295 | return idlest; | |
2296 | } | |
2297 | ||
2298 | /* | |
2299 | * find_idlest_cpu - find the idlest cpu among the cpus in group. | |
2300 | */ | |
2301 | static int | |
2302 | find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu) | |
2303 | { | |
2304 | unsigned long load, min_load = ULONG_MAX; | |
2305 | int idlest = -1; | |
2306 | int i; | |
2307 | ||
2308 | /* Traverse only the allowed CPUs */ | |
fa17b507 | 2309 | for_each_cpu_and(i, sched_group_cpus(group), tsk_cpus_allowed(p)) { |
aaee1203 PZ |
2310 | load = weighted_cpuload(i); |
2311 | ||
2312 | if (load < min_load || (load == min_load && i == this_cpu)) { | |
2313 | min_load = load; | |
2314 | idlest = i; | |
e7693a36 GH |
2315 | } |
2316 | } | |
2317 | ||
aaee1203 PZ |
2318 | return idlest; |
2319 | } | |
e7693a36 | 2320 | |
a50bde51 PZ |
2321 | /* |
2322 | * Try and locate an idle CPU in the sched_domain. | |
2323 | */ | |
99bd5e2f | 2324 | static int select_idle_sibling(struct task_struct *p, int target) |
a50bde51 PZ |
2325 | { |
2326 | int cpu = smp_processor_id(); | |
2327 | int prev_cpu = task_cpu(p); | |
99bd5e2f | 2328 | struct sched_domain *sd; |
4dcfe102 PZ |
2329 | struct sched_group *sg; |
2330 | int i, smt = 0; | |
a50bde51 PZ |
2331 | |
2332 | /* | |
99bd5e2f SS |
2333 | * If the task is going to be woken-up on this cpu and if it is |
2334 | * already idle, then it is the right target. | |
a50bde51 | 2335 | */ |
99bd5e2f SS |
2336 | if (target == cpu && idle_cpu(cpu)) |
2337 | return cpu; | |
2338 | ||
2339 | /* | |
2340 | * If the task is going to be woken-up on the cpu where it previously | |
2341 | * ran and if it is currently idle, then it the right target. | |
2342 | */ | |
2343 | if (target == prev_cpu && idle_cpu(prev_cpu)) | |
fe3bcfe1 | 2344 | return prev_cpu; |
a50bde51 PZ |
2345 | |
2346 | /* | |
99bd5e2f | 2347 | * Otherwise, iterate the domains and find an elegible idle cpu. |
a50bde51 | 2348 | */ |
dce840a0 | 2349 | rcu_read_lock(); |
4dcfe102 | 2350 | again: |
99bd5e2f | 2351 | for_each_domain(target, sd) { |
4dcfe102 PZ |
2352 | if (!smt && (sd->flags & SD_SHARE_CPUPOWER)) |
2353 | continue; | |
99bd5e2f | 2354 | |
ab278921 PZ |
2355 | if (smt && !(sd->flags & SD_SHARE_CPUPOWER)) |
2356 | break; | |
2357 | ||
2358 | if (!(sd->flags & SD_SHARE_PKG_RESOURCES)) | |
4dcfe102 | 2359 | break; |
99bd5e2f | 2360 | |
4dcfe102 PZ |
2361 | sg = sd->groups; |
2362 | do { | |
2363 | if (!cpumask_intersects(sched_group_cpus(sg), | |
2364 | tsk_cpus_allowed(p))) | |
2365 | goto next; | |
2366 | ||
2367 | for_each_cpu(i, sched_group_cpus(sg)) { | |
2368 | if (!idle_cpu(i)) | |
2369 | goto next; | |
2370 | } | |
2371 | ||
2372 | target = cpumask_first_and(sched_group_cpus(sg), | |
2373 | tsk_cpus_allowed(p)); | |
2374 | goto done; | |
2375 | next: | |
2376 | sg = sg->next; | |
2377 | } while (sg != sd->groups); | |
a50bde51 | 2378 | } |
ab278921 PZ |
2379 | if (!smt) { |
2380 | smt = 1; | |
2381 | goto again; | |
2382 | } | |
4dcfe102 | 2383 | done: |
dce840a0 | 2384 | rcu_read_unlock(); |
a50bde51 PZ |
2385 | |
2386 | return target; | |
2387 | } | |
2388 | ||
aaee1203 PZ |
2389 | /* |
2390 | * sched_balance_self: balance the current task (running on cpu) in domains | |
2391 | * that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and | |
2392 | * SD_BALANCE_EXEC. | |
2393 | * | |
2394 | * Balance, ie. select the least loaded group. | |
2395 | * | |
2396 | * Returns the target CPU number, or the same CPU if no balancing is needed. | |
2397 | * | |
2398 | * preempt must be disabled. | |
2399 | */ | |
0017d735 | 2400 | static int |
7608dec2 | 2401 | select_task_rq_fair(struct task_struct *p, int sd_flag, int wake_flags) |
aaee1203 | 2402 | { |
29cd8bae | 2403 | struct sched_domain *tmp, *affine_sd = NULL, *sd = NULL; |
c88d5910 PZ |
2404 | int cpu = smp_processor_id(); |
2405 | int prev_cpu = task_cpu(p); | |
2406 | int new_cpu = cpu; | |
99bd5e2f | 2407 | int want_affine = 0; |
29cd8bae | 2408 | int want_sd = 1; |
5158f4e4 | 2409 | int sync = wake_flags & WF_SYNC; |
c88d5910 | 2410 | |
0763a660 | 2411 | if (sd_flag & SD_BALANCE_WAKE) { |
fa17b507 | 2412 | if (cpumask_test_cpu(cpu, tsk_cpus_allowed(p))) |
c88d5910 PZ |
2413 | want_affine = 1; |
2414 | new_cpu = prev_cpu; | |
2415 | } | |
aaee1203 | 2416 | |
dce840a0 | 2417 | rcu_read_lock(); |
aaee1203 | 2418 | for_each_domain(cpu, tmp) { |
e4f42888 PZ |
2419 | if (!(tmp->flags & SD_LOAD_BALANCE)) |
2420 | continue; | |
2421 | ||
aaee1203 | 2422 | /* |
ae154be1 PZ |
2423 | * If power savings logic is enabled for a domain, see if we |
2424 | * are not overloaded, if so, don't balance wider. | |
aaee1203 | 2425 | */ |
59abf026 | 2426 | if (tmp->flags & (SD_POWERSAVINGS_BALANCE|SD_PREFER_LOCAL)) { |
ae154be1 PZ |
2427 | unsigned long power = 0; |
2428 | unsigned long nr_running = 0; | |
2429 | unsigned long capacity; | |
2430 | int i; | |
2431 | ||
2432 | for_each_cpu(i, sched_domain_span(tmp)) { | |
2433 | power += power_of(i); | |
2434 | nr_running += cpu_rq(i)->cfs.nr_running; | |
2435 | } | |
2436 | ||
1399fa78 | 2437 | capacity = DIV_ROUND_CLOSEST(power, SCHED_POWER_SCALE); |
ae154be1 | 2438 | |
59abf026 PZ |
2439 | if (tmp->flags & SD_POWERSAVINGS_BALANCE) |
2440 | nr_running /= 2; | |
2441 | ||
2442 | if (nr_running < capacity) | |
29cd8bae | 2443 | want_sd = 0; |
ae154be1 | 2444 | } |
aaee1203 | 2445 | |
fe3bcfe1 | 2446 | /* |
99bd5e2f SS |
2447 | * If both cpu and prev_cpu are part of this domain, |
2448 | * cpu is a valid SD_WAKE_AFFINE target. | |
fe3bcfe1 | 2449 | */ |
99bd5e2f SS |
2450 | if (want_affine && (tmp->flags & SD_WAKE_AFFINE) && |
2451 | cpumask_test_cpu(prev_cpu, sched_domain_span(tmp))) { | |
2452 | affine_sd = tmp; | |
2453 | want_affine = 0; | |
c88d5910 PZ |
2454 | } |
2455 | ||
29cd8bae PZ |
2456 | if (!want_sd && !want_affine) |
2457 | break; | |
2458 | ||
0763a660 | 2459 | if (!(tmp->flags & sd_flag)) |
c88d5910 PZ |
2460 | continue; |
2461 | ||
29cd8bae PZ |
2462 | if (want_sd) |
2463 | sd = tmp; | |
2464 | } | |
2465 | ||
8b911acd | 2466 | if (affine_sd) { |
99bd5e2f | 2467 | if (cpu == prev_cpu || wake_affine(affine_sd, p, sync)) |
dce840a0 PZ |
2468 | prev_cpu = cpu; |
2469 | ||
2470 | new_cpu = select_idle_sibling(p, prev_cpu); | |
2471 | goto unlock; | |
8b911acd | 2472 | } |
e7693a36 | 2473 | |
aaee1203 | 2474 | while (sd) { |
5158f4e4 | 2475 | int load_idx = sd->forkexec_idx; |
aaee1203 | 2476 | struct sched_group *group; |
c88d5910 | 2477 | int weight; |
098fb9db | 2478 | |
0763a660 | 2479 | if (!(sd->flags & sd_flag)) { |
aaee1203 PZ |
2480 | sd = sd->child; |
2481 | continue; | |
2482 | } | |
098fb9db | 2483 | |
5158f4e4 PZ |
2484 | if (sd_flag & SD_BALANCE_WAKE) |
2485 | load_idx = sd->wake_idx; | |
098fb9db | 2486 | |
5158f4e4 | 2487 | group = find_idlest_group(sd, p, cpu, load_idx); |
aaee1203 PZ |
2488 | if (!group) { |
2489 | sd = sd->child; | |
2490 | continue; | |
2491 | } | |
4ae7d5ce | 2492 | |
d7c33c49 | 2493 | new_cpu = find_idlest_cpu(group, p, cpu); |
aaee1203 PZ |
2494 | if (new_cpu == -1 || new_cpu == cpu) { |
2495 | /* Now try balancing at a lower domain level of cpu */ | |
2496 | sd = sd->child; | |
2497 | continue; | |
e7693a36 | 2498 | } |
aaee1203 PZ |
2499 | |
2500 | /* Now try balancing at a lower domain level of new_cpu */ | |
2501 | cpu = new_cpu; | |
669c55e9 | 2502 | weight = sd->span_weight; |
aaee1203 PZ |
2503 | sd = NULL; |
2504 | for_each_domain(cpu, tmp) { | |
669c55e9 | 2505 | if (weight <= tmp->span_weight) |
aaee1203 | 2506 | break; |
0763a660 | 2507 | if (tmp->flags & sd_flag) |
aaee1203 PZ |
2508 | sd = tmp; |
2509 | } | |
2510 | /* while loop will break here if sd == NULL */ | |
e7693a36 | 2511 | } |
dce840a0 PZ |
2512 | unlock: |
2513 | rcu_read_unlock(); | |
e7693a36 | 2514 | |
c88d5910 | 2515 | return new_cpu; |
e7693a36 GH |
2516 | } |
2517 | #endif /* CONFIG_SMP */ | |
2518 | ||
e52fb7c0 PZ |
2519 | static unsigned long |
2520 | wakeup_gran(struct sched_entity *curr, struct sched_entity *se) | |
0bbd3336 PZ |
2521 | { |
2522 | unsigned long gran = sysctl_sched_wakeup_granularity; | |
2523 | ||
2524 | /* | |
e52fb7c0 PZ |
2525 | * Since its curr running now, convert the gran from real-time |
2526 | * to virtual-time in his units. | |
13814d42 MG |
2527 | * |
2528 | * By using 'se' instead of 'curr' we penalize light tasks, so | |
2529 | * they get preempted easier. That is, if 'se' < 'curr' then | |
2530 | * the resulting gran will be larger, therefore penalizing the | |
2531 | * lighter, if otoh 'se' > 'curr' then the resulting gran will | |
2532 | * be smaller, again penalizing the lighter task. | |
2533 | * | |
2534 | * This is especially important for buddies when the leftmost | |
2535 | * task is higher priority than the buddy. | |
0bbd3336 | 2536 | */ |
f4ad9bd2 | 2537 | return calc_delta_fair(gran, se); |
0bbd3336 PZ |
2538 | } |
2539 | ||
464b7527 PZ |
2540 | /* |
2541 | * Should 'se' preempt 'curr'. | |
2542 | * | |
2543 | * |s1 | |
2544 | * |s2 | |
2545 | * |s3 | |
2546 | * g | |
2547 | * |<--->|c | |
2548 | * | |
2549 | * w(c, s1) = -1 | |
2550 | * w(c, s2) = 0 | |
2551 | * w(c, s3) = 1 | |
2552 | * | |
2553 | */ | |
2554 | static int | |
2555 | wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se) | |
2556 | { | |
2557 | s64 gran, vdiff = curr->vruntime - se->vruntime; | |
2558 | ||
2559 | if (vdiff <= 0) | |
2560 | return -1; | |
2561 | ||
e52fb7c0 | 2562 | gran = wakeup_gran(curr, se); |
464b7527 PZ |
2563 | if (vdiff > gran) |
2564 | return 1; | |
2565 | ||
2566 | return 0; | |
2567 | } | |
2568 | ||
02479099 PZ |
2569 | static void set_last_buddy(struct sched_entity *se) |
2570 | { | |
69c80f3e VP |
2571 | if (entity_is_task(se) && unlikely(task_of(se)->policy == SCHED_IDLE)) |
2572 | return; | |
2573 | ||
2574 | for_each_sched_entity(se) | |
2575 | cfs_rq_of(se)->last = se; | |
02479099 PZ |
2576 | } |
2577 | ||
2578 | static void set_next_buddy(struct sched_entity *se) | |
2579 | { | |
69c80f3e VP |
2580 | if (entity_is_task(se) && unlikely(task_of(se)->policy == SCHED_IDLE)) |
2581 | return; | |
2582 | ||
2583 | for_each_sched_entity(se) | |
2584 | cfs_rq_of(se)->next = se; | |
02479099 PZ |
2585 | } |
2586 | ||
ac53db59 RR |
2587 | static void set_skip_buddy(struct sched_entity *se) |
2588 | { | |
69c80f3e VP |
2589 | for_each_sched_entity(se) |
2590 | cfs_rq_of(se)->skip = se; | |
ac53db59 RR |
2591 | } |
2592 | ||
bf0f6f24 IM |
2593 | /* |
2594 | * Preempt the current task with a newly woken task if needed: | |
2595 | */ | |
5a9b86f6 | 2596 | static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_flags) |
bf0f6f24 IM |
2597 | { |
2598 | struct task_struct *curr = rq->curr; | |
8651a86c | 2599 | struct sched_entity *se = &curr->se, *pse = &p->se; |
03e89e45 | 2600 | struct cfs_rq *cfs_rq = task_cfs_rq(curr); |
f685ceac | 2601 | int scale = cfs_rq->nr_running >= sched_nr_latency; |
2f36825b | 2602 | int next_buddy_marked = 0; |
bf0f6f24 | 2603 | |
4ae7d5ce IM |
2604 | if (unlikely(se == pse)) |
2605 | return; | |
2606 | ||
5238cdd3 PT |
2607 | /* |
2608 | * This is possible from callers such as pull_task(), in which we | |
2609 | * unconditionally check_prempt_curr() after an enqueue (which may have | |
2610 | * lead to a throttle). This both saves work and prevents false | |
2611 | * next-buddy nomination below. | |
2612 | */ | |
2613 | if (unlikely(throttled_hierarchy(cfs_rq_of(pse)))) | |
2614 | return; | |
2615 | ||
2f36825b | 2616 | if (sched_feat(NEXT_BUDDY) && scale && !(wake_flags & WF_FORK)) { |
3cb63d52 | 2617 | set_next_buddy(pse); |
2f36825b VP |
2618 | next_buddy_marked = 1; |
2619 | } | |
57fdc26d | 2620 | |
aec0a514 BR |
2621 | /* |
2622 | * We can come here with TIF_NEED_RESCHED already set from new task | |
2623 | * wake up path. | |
5238cdd3 PT |
2624 | * |
2625 | * Note: this also catches the edge-case of curr being in a throttled | |
2626 | * group (e.g. via set_curr_task), since update_curr() (in the | |
2627 | * enqueue of curr) will have resulted in resched being set. This | |
2628 | * prevents us from potentially nominating it as a false LAST_BUDDY | |
2629 | * below. | |
aec0a514 BR |
2630 | */ |
2631 | if (test_tsk_need_resched(curr)) | |
2632 | return; | |
2633 | ||
a2f5c9ab DH |
2634 | /* Idle tasks are by definition preempted by non-idle tasks. */ |
2635 | if (unlikely(curr->policy == SCHED_IDLE) && | |
2636 | likely(p->policy != SCHED_IDLE)) | |
2637 | goto preempt; | |
2638 | ||
91c234b4 | 2639 | /* |
a2f5c9ab DH |
2640 | * Batch and idle tasks do not preempt non-idle tasks (their preemption |
2641 | * is driven by the tick): | |
91c234b4 | 2642 | */ |
6bc912b7 | 2643 | if (unlikely(p->policy != SCHED_NORMAL)) |
91c234b4 | 2644 | return; |
bf0f6f24 | 2645 | |
464b7527 | 2646 | find_matching_se(&se, &pse); |
9bbd7374 | 2647 | update_curr(cfs_rq_of(se)); |
002f128b | 2648 | BUG_ON(!pse); |
2f36825b VP |
2649 | if (wakeup_preempt_entity(se, pse) == 1) { |
2650 | /* | |
2651 | * Bias pick_next to pick the sched entity that is | |
2652 | * triggering this preemption. | |
2653 | */ | |
2654 | if (!next_buddy_marked) | |
2655 | set_next_buddy(pse); | |
3a7e73a2 | 2656 | goto preempt; |
2f36825b | 2657 | } |
464b7527 | 2658 | |
3a7e73a2 | 2659 | return; |
a65ac745 | 2660 | |
3a7e73a2 PZ |
2661 | preempt: |
2662 | resched_task(curr); | |
2663 | /* | |
2664 | * Only set the backward buddy when the current task is still | |
2665 | * on the rq. This can happen when a wakeup gets interleaved | |
2666 | * with schedule on the ->pre_schedule() or idle_balance() | |
2667 | * point, either of which can * drop the rq lock. | |
2668 | * | |
2669 | * Also, during early boot the idle thread is in the fair class, | |
2670 | * for obvious reasons its a bad idea to schedule back to it. | |
2671 | */ | |
2672 | if (unlikely(!se->on_rq || curr == rq->idle)) | |
2673 | return; | |
2674 | ||
2675 | if (sched_feat(LAST_BUDDY) && scale && entity_is_task(se)) | |
2676 | set_last_buddy(se); | |
bf0f6f24 IM |
2677 | } |
2678 | ||
fb8d4724 | 2679 | static struct task_struct *pick_next_task_fair(struct rq *rq) |
bf0f6f24 | 2680 | { |
8f4d37ec | 2681 | struct task_struct *p; |
bf0f6f24 IM |
2682 | struct cfs_rq *cfs_rq = &rq->cfs; |
2683 | struct sched_entity *se; | |
2684 | ||
36ace27e | 2685 | if (!cfs_rq->nr_running) |
bf0f6f24 IM |
2686 | return NULL; |
2687 | ||
2688 | do { | |
9948f4b2 | 2689 | se = pick_next_entity(cfs_rq); |
f4b6755f | 2690 | set_next_entity(cfs_rq, se); |
bf0f6f24 IM |
2691 | cfs_rq = group_cfs_rq(se); |
2692 | } while (cfs_rq); | |
2693 | ||
8f4d37ec PZ |
2694 | p = task_of(se); |
2695 | hrtick_start_fair(rq, p); | |
2696 | ||
2697 | return p; | |
bf0f6f24 IM |
2698 | } |
2699 | ||
2700 | /* | |
2701 | * Account for a descheduled task: | |
2702 | */ | |
31ee529c | 2703 | static void put_prev_task_fair(struct rq *rq, struct task_struct *prev) |
bf0f6f24 IM |
2704 | { |
2705 | struct sched_entity *se = &prev->se; | |
2706 | struct cfs_rq *cfs_rq; | |
2707 | ||
2708 | for_each_sched_entity(se) { | |
2709 | cfs_rq = cfs_rq_of(se); | |
ab6cde26 | 2710 | put_prev_entity(cfs_rq, se); |
bf0f6f24 IM |
2711 | } |
2712 | } | |
2713 | ||
ac53db59 RR |
2714 | /* |
2715 | * sched_yield() is very simple | |
2716 | * | |
2717 | * The magic of dealing with the ->skip buddy is in pick_next_entity. | |
2718 | */ | |
2719 | static void yield_task_fair(struct rq *rq) | |
2720 | { | |
2721 | struct task_struct *curr = rq->curr; | |
2722 | struct cfs_rq *cfs_rq = task_cfs_rq(curr); | |
2723 | struct sched_entity *se = &curr->se; | |
2724 | ||
2725 | /* | |
2726 | * Are we the only task in the tree? | |
2727 | */ | |
2728 | if (unlikely(rq->nr_running == 1)) | |
2729 | return; | |
2730 | ||
2731 | clear_buddies(cfs_rq, se); | |
2732 | ||
2733 | if (curr->policy != SCHED_BATCH) { | |
2734 | update_rq_clock(rq); | |
2735 | /* | |
2736 | * Update run-time statistics of the 'current'. | |
2737 | */ | |
2738 | update_curr(cfs_rq); | |
2739 | } | |
2740 | ||
2741 | set_skip_buddy(se); | |
2742 | } | |
2743 | ||
d95f4122 MG |
2744 | static bool yield_to_task_fair(struct rq *rq, struct task_struct *p, bool preempt) |
2745 | { | |
2746 | struct sched_entity *se = &p->se; | |
2747 | ||
5238cdd3 PT |
2748 | /* throttled hierarchies are not runnable */ |
2749 | if (!se->on_rq || throttled_hierarchy(cfs_rq_of(se))) | |
d95f4122 MG |
2750 | return false; |
2751 | ||
2752 | /* Tell the scheduler that we'd really like pse to run next. */ | |
2753 | set_next_buddy(se); | |
2754 | ||
d95f4122 MG |
2755 | yield_task_fair(rq); |
2756 | ||
2757 | return true; | |
2758 | } | |
2759 | ||
681f3e68 | 2760 | #ifdef CONFIG_SMP |
bf0f6f24 IM |
2761 | /************************************************** |
2762 | * Fair scheduling class load-balancing methods: | |
2763 | */ | |
2764 | ||
1e3c88bd PZ |
2765 | /* |
2766 | * pull_task - move a task from a remote runqueue to the local runqueue. | |
2767 | * Both runqueues must be locked. | |
2768 | */ | |
2769 | static void pull_task(struct rq *src_rq, struct task_struct *p, | |
2770 | struct rq *this_rq, int this_cpu) | |
2771 | { | |
2772 | deactivate_task(src_rq, p, 0); | |
2773 | set_task_cpu(p, this_cpu); | |
2774 | activate_task(this_rq, p, 0); | |
2775 | check_preempt_curr(this_rq, p, 0); | |
2776 | } | |
2777 | ||
2778 | /* | |
2779 | * can_migrate_task - may task p from runqueue rq be migrated to this_cpu? | |
2780 | */ | |
2781 | static | |
2782 | int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu, | |
2783 | struct sched_domain *sd, enum cpu_idle_type idle, | |
2784 | int *all_pinned) | |
2785 | { | |
2786 | int tsk_cache_hot = 0; | |
2787 | /* | |
2788 | * We do not migrate tasks that are: | |
2789 | * 1) running (obviously), or | |
2790 | * 2) cannot be migrated to this CPU due to cpus_allowed, or | |
2791 | * 3) are cache-hot on their current CPU. | |
2792 | */ | |
fa17b507 | 2793 | if (!cpumask_test_cpu(this_cpu, tsk_cpus_allowed(p))) { |
41acab88 | 2794 | schedstat_inc(p, se.statistics.nr_failed_migrations_affine); |
1e3c88bd PZ |
2795 | return 0; |
2796 | } | |
2797 | *all_pinned = 0; | |
2798 | ||
2799 | if (task_running(rq, p)) { | |
41acab88 | 2800 | schedstat_inc(p, se.statistics.nr_failed_migrations_running); |
1e3c88bd PZ |
2801 | return 0; |
2802 | } | |
2803 | ||
2804 | /* | |
2805 | * Aggressive migration if: | |
2806 | * 1) task is cache cold, or | |
2807 | * 2) too many balance attempts have failed. | |
2808 | */ | |
2809 | ||
305e6835 | 2810 | tsk_cache_hot = task_hot(p, rq->clock_task, sd); |
1e3c88bd PZ |
2811 | if (!tsk_cache_hot || |
2812 | sd->nr_balance_failed > sd->cache_nice_tries) { | |
2813 | #ifdef CONFIG_SCHEDSTATS | |
2814 | if (tsk_cache_hot) { | |
2815 | schedstat_inc(sd, lb_hot_gained[idle]); | |
41acab88 | 2816 | schedstat_inc(p, se.statistics.nr_forced_migrations); |
1e3c88bd PZ |
2817 | } |
2818 | #endif | |
2819 | return 1; | |
2820 | } | |
2821 | ||
2822 | if (tsk_cache_hot) { | |
41acab88 | 2823 | schedstat_inc(p, se.statistics.nr_failed_migrations_hot); |
1e3c88bd PZ |
2824 | return 0; |
2825 | } | |
2826 | return 1; | |
2827 | } | |
2828 | ||
897c395f PZ |
2829 | /* |
2830 | * move_one_task tries to move exactly one task from busiest to this_rq, as | |
2831 | * part of active balancing operations within "domain". | |
2832 | * Returns 1 if successful and 0 otherwise. | |
2833 | * | |
2834 | * Called with both runqueues locked. | |
2835 | */ | |
2836 | static int | |
2837 | move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
2838 | struct sched_domain *sd, enum cpu_idle_type idle) | |
2839 | { | |
2840 | struct task_struct *p, *n; | |
2841 | struct cfs_rq *cfs_rq; | |
2842 | int pinned = 0; | |
2843 | ||
2844 | for_each_leaf_cfs_rq(busiest, cfs_rq) { | |
2845 | list_for_each_entry_safe(p, n, &cfs_rq->tasks, se.group_node) { | |
64660c86 PT |
2846 | if (throttled_lb_pair(task_group(p), |
2847 | busiest->cpu, this_cpu)) | |
2848 | break; | |
897c395f PZ |
2849 | |
2850 | if (!can_migrate_task(p, busiest, this_cpu, | |
2851 | sd, idle, &pinned)) | |
2852 | continue; | |
2853 | ||
2854 | pull_task(busiest, p, this_rq, this_cpu); | |
2855 | /* | |
2856 | * Right now, this is only the second place pull_task() | |
2857 | * is called, so we can safely collect pull_task() | |
2858 | * stats here rather than inside pull_task(). | |
2859 | */ | |
2860 | schedstat_inc(sd, lb_gained[idle]); | |
2861 | return 1; | |
2862 | } | |
2863 | } | |
2864 | ||
2865 | return 0; | |
2866 | } | |
2867 | ||
1e3c88bd PZ |
2868 | static unsigned long |
2869 | balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
2870 | unsigned long max_load_move, struct sched_domain *sd, | |
2871 | enum cpu_idle_type idle, int *all_pinned, | |
931aeeda | 2872 | struct cfs_rq *busiest_cfs_rq) |
1e3c88bd | 2873 | { |
b30aef17 | 2874 | int loops = 0, pulled = 0; |
1e3c88bd | 2875 | long rem_load_move = max_load_move; |
ee00e66f | 2876 | struct task_struct *p, *n; |
1e3c88bd PZ |
2877 | |
2878 | if (max_load_move == 0) | |
2879 | goto out; | |
2880 | ||
ee00e66f PZ |
2881 | list_for_each_entry_safe(p, n, &busiest_cfs_rq->tasks, se.group_node) { |
2882 | if (loops++ > sysctl_sched_nr_migrate) | |
2883 | break; | |
1e3c88bd | 2884 | |
ee00e66f | 2885 | if ((p->se.load.weight >> 1) > rem_load_move || |
b30aef17 KC |
2886 | !can_migrate_task(p, busiest, this_cpu, sd, idle, |
2887 | all_pinned)) | |
ee00e66f | 2888 | continue; |
1e3c88bd | 2889 | |
ee00e66f PZ |
2890 | pull_task(busiest, p, this_rq, this_cpu); |
2891 | pulled++; | |
2892 | rem_load_move -= p->se.load.weight; | |
1e3c88bd PZ |
2893 | |
2894 | #ifdef CONFIG_PREEMPT | |
ee00e66f PZ |
2895 | /* |
2896 | * NEWIDLE balancing is a source of latency, so preemptible | |
2897 | * kernels will stop after the first task is pulled to minimize | |
2898 | * the critical section. | |
2899 | */ | |
2900 | if (idle == CPU_NEWLY_IDLE) | |
2901 | break; | |
1e3c88bd PZ |
2902 | #endif |
2903 | ||
ee00e66f PZ |
2904 | /* |
2905 | * We only want to steal up to the prescribed amount of | |
2906 | * weighted load. | |
2907 | */ | |
2908 | if (rem_load_move <= 0) | |
2909 | break; | |
1e3c88bd PZ |
2910 | } |
2911 | out: | |
2912 | /* | |
2913 | * Right now, this is one of only two places pull_task() is called, | |
2914 | * so we can safely collect pull_task() stats here rather than | |
2915 | * inside pull_task(). | |
2916 | */ | |
2917 | schedstat_add(sd, lb_gained[idle], pulled); | |
2918 | ||
1e3c88bd PZ |
2919 | return max_load_move - rem_load_move; |
2920 | } | |
2921 | ||
230059de | 2922 | #ifdef CONFIG_FAIR_GROUP_SCHED |
9e3081ca PZ |
2923 | /* |
2924 | * update tg->load_weight by folding this cpu's load_avg | |
2925 | */ | |
67e86250 | 2926 | static int update_shares_cpu(struct task_group *tg, int cpu) |
9e3081ca PZ |
2927 | { |
2928 | struct cfs_rq *cfs_rq; | |
2929 | unsigned long flags; | |
2930 | struct rq *rq; | |
9e3081ca PZ |
2931 | |
2932 | if (!tg->se[cpu]) | |
2933 | return 0; | |
2934 | ||
2935 | rq = cpu_rq(cpu); | |
2936 | cfs_rq = tg->cfs_rq[cpu]; | |
2937 | ||
2938 | raw_spin_lock_irqsave(&rq->lock, flags); | |
2939 | ||
2940 | update_rq_clock(rq); | |
d6b55918 | 2941 | update_cfs_load(cfs_rq, 1); |
9e3081ca PZ |
2942 | |
2943 | /* | |
2944 | * We need to update shares after updating tg->load_weight in | |
2945 | * order to adjust the weight of groups with long running tasks. | |
2946 | */ | |
6d5ab293 | 2947 | update_cfs_shares(cfs_rq); |
9e3081ca PZ |
2948 | |
2949 | raw_spin_unlock_irqrestore(&rq->lock, flags); | |
2950 | ||
2951 | return 0; | |
2952 | } | |
2953 | ||
2954 | static void update_shares(int cpu) | |
2955 | { | |
2956 | struct cfs_rq *cfs_rq; | |
2957 | struct rq *rq = cpu_rq(cpu); | |
2958 | ||
2959 | rcu_read_lock(); | |
9763b67f PZ |
2960 | /* |
2961 | * Iterates the task_group tree in a bottom up fashion, see | |
2962 | * list_add_leaf_cfs_rq() for details. | |
2963 | */ | |
64660c86 PT |
2964 | for_each_leaf_cfs_rq(rq, cfs_rq) { |
2965 | /* throttled entities do not contribute to load */ | |
2966 | if (throttled_hierarchy(cfs_rq)) | |
2967 | continue; | |
2968 | ||
67e86250 | 2969 | update_shares_cpu(cfs_rq->tg, cpu); |
64660c86 | 2970 | } |
9e3081ca PZ |
2971 | rcu_read_unlock(); |
2972 | } | |
2973 | ||
9763b67f PZ |
2974 | /* |
2975 | * Compute the cpu's hierarchical load factor for each task group. | |
2976 | * This needs to be done in a top-down fashion because the load of a child | |
2977 | * group is a fraction of its parents load. | |
2978 | */ | |
2979 | static int tg_load_down(struct task_group *tg, void *data) | |
2980 | { | |
2981 | unsigned long load; | |
2982 | long cpu = (long)data; | |
2983 | ||
2984 | if (!tg->parent) { | |
2985 | load = cpu_rq(cpu)->load.weight; | |
2986 | } else { | |
2987 | load = tg->parent->cfs_rq[cpu]->h_load; | |
2988 | load *= tg->se[cpu]->load.weight; | |
2989 | load /= tg->parent->cfs_rq[cpu]->load.weight + 1; | |
2990 | } | |
2991 | ||
2992 | tg->cfs_rq[cpu]->h_load = load; | |
2993 | ||
2994 | return 0; | |
2995 | } | |
2996 | ||
2997 | static void update_h_load(long cpu) | |
2998 | { | |
2999 | walk_tg_tree(tg_load_down, tg_nop, (void *)cpu); | |
3000 | } | |
3001 | ||
230059de PZ |
3002 | static unsigned long |
3003 | load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
3004 | unsigned long max_load_move, | |
3005 | struct sched_domain *sd, enum cpu_idle_type idle, | |
931aeeda | 3006 | int *all_pinned) |
230059de PZ |
3007 | { |
3008 | long rem_load_move = max_load_move; | |
9763b67f | 3009 | struct cfs_rq *busiest_cfs_rq; |
230059de PZ |
3010 | |
3011 | rcu_read_lock(); | |
9763b67f | 3012 | update_h_load(cpu_of(busiest)); |
230059de | 3013 | |
9763b67f | 3014 | for_each_leaf_cfs_rq(busiest, busiest_cfs_rq) { |
230059de PZ |
3015 | unsigned long busiest_h_load = busiest_cfs_rq->h_load; |
3016 | unsigned long busiest_weight = busiest_cfs_rq->load.weight; | |
3017 | u64 rem_load, moved_load; | |
3018 | ||
3019 | /* | |
64660c86 | 3020 | * empty group or part of a throttled hierarchy |
230059de | 3021 | */ |
64660c86 PT |
3022 | if (!busiest_cfs_rq->task_weight || |
3023 | throttled_lb_pair(busiest_cfs_rq->tg, cpu_of(busiest), this_cpu)) | |
230059de PZ |
3024 | continue; |
3025 | ||
3026 | rem_load = (u64)rem_load_move * busiest_weight; | |
3027 | rem_load = div_u64(rem_load, busiest_h_load + 1); | |
3028 | ||
3029 | moved_load = balance_tasks(this_rq, this_cpu, busiest, | |
931aeeda | 3030 | rem_load, sd, idle, all_pinned, |
230059de PZ |
3031 | busiest_cfs_rq); |
3032 | ||
3033 | if (!moved_load) | |
3034 | continue; | |
3035 | ||
3036 | moved_load *= busiest_h_load; | |
3037 | moved_load = div_u64(moved_load, busiest_weight + 1); | |
3038 | ||
3039 | rem_load_move -= moved_load; | |
3040 | if (rem_load_move < 0) | |
3041 | break; | |
3042 | } | |
3043 | rcu_read_unlock(); | |
3044 | ||
3045 | return max_load_move - rem_load_move; | |
3046 | } | |
3047 | #else | |
9e3081ca PZ |
3048 | static inline void update_shares(int cpu) |
3049 | { | |
3050 | } | |
3051 | ||
230059de PZ |
3052 | static unsigned long |
3053 | load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
3054 | unsigned long max_load_move, | |
3055 | struct sched_domain *sd, enum cpu_idle_type idle, | |
931aeeda | 3056 | int *all_pinned) |
230059de PZ |
3057 | { |
3058 | return balance_tasks(this_rq, this_cpu, busiest, | |
3059 | max_load_move, sd, idle, all_pinned, | |
931aeeda | 3060 | &busiest->cfs); |
230059de PZ |
3061 | } |
3062 | #endif | |
3063 | ||
1e3c88bd PZ |
3064 | /* |
3065 | * move_tasks tries to move up to max_load_move weighted load from busiest to | |
3066 | * this_rq, as part of a balancing operation within domain "sd". | |
3067 | * Returns 1 if successful and 0 otherwise. | |
3068 | * | |
3069 | * Called with both runqueues locked. | |
3070 | */ | |
3071 | static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
3072 | unsigned long max_load_move, | |
3073 | struct sched_domain *sd, enum cpu_idle_type idle, | |
3074 | int *all_pinned) | |
3075 | { | |
3d45fd80 | 3076 | unsigned long total_load_moved = 0, load_moved; |
1e3c88bd PZ |
3077 | |
3078 | do { | |
3d45fd80 | 3079 | load_moved = load_balance_fair(this_rq, this_cpu, busiest, |
1e3c88bd | 3080 | max_load_move - total_load_moved, |
931aeeda | 3081 | sd, idle, all_pinned); |
3d45fd80 PZ |
3082 | |
3083 | total_load_moved += load_moved; | |
1e3c88bd PZ |
3084 | |
3085 | #ifdef CONFIG_PREEMPT | |
3086 | /* | |
3087 | * NEWIDLE balancing is a source of latency, so preemptible | |
3088 | * kernels will stop after the first task is pulled to minimize | |
3089 | * the critical section. | |
3090 | */ | |
3091 | if (idle == CPU_NEWLY_IDLE && this_rq->nr_running) | |
3092 | break; | |
baa8c110 PZ |
3093 | |
3094 | if (raw_spin_is_contended(&this_rq->lock) || | |
3095 | raw_spin_is_contended(&busiest->lock)) | |
3096 | break; | |
1e3c88bd | 3097 | #endif |
3d45fd80 | 3098 | } while (load_moved && max_load_move > total_load_moved); |
1e3c88bd PZ |
3099 | |
3100 | return total_load_moved > 0; | |
3101 | } | |
3102 | ||
1e3c88bd PZ |
3103 | /********** Helpers for find_busiest_group ************************/ |
3104 | /* | |
3105 | * sd_lb_stats - Structure to store the statistics of a sched_domain | |
3106 | * during load balancing. | |
3107 | */ | |
3108 | struct sd_lb_stats { | |
3109 | struct sched_group *busiest; /* Busiest group in this sd */ | |
3110 | struct sched_group *this; /* Local group in this sd */ | |
3111 | unsigned long total_load; /* Total load of all groups in sd */ | |
3112 | unsigned long total_pwr; /* Total power of all groups in sd */ | |
3113 | unsigned long avg_load; /* Average load across all groups in sd */ | |
3114 | ||
3115 | /** Statistics of this group */ | |
3116 | unsigned long this_load; | |
3117 | unsigned long this_load_per_task; | |
3118 | unsigned long this_nr_running; | |
fab47622 | 3119 | unsigned long this_has_capacity; |
aae6d3dd | 3120 | unsigned int this_idle_cpus; |
1e3c88bd PZ |
3121 | |
3122 | /* Statistics of the busiest group */ | |
aae6d3dd | 3123 | unsigned int busiest_idle_cpus; |
1e3c88bd PZ |
3124 | unsigned long max_load; |
3125 | unsigned long busiest_load_per_task; | |
3126 | unsigned long busiest_nr_running; | |
dd5feea1 | 3127 | unsigned long busiest_group_capacity; |
fab47622 | 3128 | unsigned long busiest_has_capacity; |
aae6d3dd | 3129 | unsigned int busiest_group_weight; |
1e3c88bd PZ |
3130 | |
3131 | int group_imb; /* Is there imbalance in this sd */ | |
3132 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) | |
3133 | int power_savings_balance; /* Is powersave balance needed for this sd */ | |
3134 | struct sched_group *group_min; /* Least loaded group in sd */ | |
3135 | struct sched_group *group_leader; /* Group which relieves group_min */ | |
3136 | unsigned long min_load_per_task; /* load_per_task in group_min */ | |
3137 | unsigned long leader_nr_running; /* Nr running of group_leader */ | |
3138 | unsigned long min_nr_running; /* Nr running of group_min */ | |
3139 | #endif | |
3140 | }; | |
3141 | ||
3142 | /* | |
3143 | * sg_lb_stats - stats of a sched_group required for load_balancing | |
3144 | */ | |
3145 | struct sg_lb_stats { | |
3146 | unsigned long avg_load; /*Avg load across the CPUs of the group */ | |
3147 | unsigned long group_load; /* Total load over the CPUs of the group */ | |
3148 | unsigned long sum_nr_running; /* Nr tasks running in the group */ | |
3149 | unsigned long sum_weighted_load; /* Weighted load of group's tasks */ | |
3150 | unsigned long group_capacity; | |
aae6d3dd SS |
3151 | unsigned long idle_cpus; |
3152 | unsigned long group_weight; | |
1e3c88bd | 3153 | int group_imb; /* Is there an imbalance in the group ? */ |
fab47622 | 3154 | int group_has_capacity; /* Is there extra capacity in the group? */ |
1e3c88bd PZ |
3155 | }; |
3156 | ||
3157 | /** | |
3158 | * group_first_cpu - Returns the first cpu in the cpumask of a sched_group. | |
3159 | * @group: The group whose first cpu is to be returned. | |
3160 | */ | |
3161 | static inline unsigned int group_first_cpu(struct sched_group *group) | |
3162 | { | |
3163 | return cpumask_first(sched_group_cpus(group)); | |
3164 | } | |
3165 | ||
3166 | /** | |
3167 | * get_sd_load_idx - Obtain the load index for a given sched domain. | |
3168 | * @sd: The sched_domain whose load_idx is to be obtained. | |
3169 | * @idle: The Idle status of the CPU for whose sd load_icx is obtained. | |
3170 | */ | |
3171 | static inline int get_sd_load_idx(struct sched_domain *sd, | |
3172 | enum cpu_idle_type idle) | |
3173 | { | |
3174 | int load_idx; | |
3175 | ||
3176 | switch (idle) { | |
3177 | case CPU_NOT_IDLE: | |
3178 | load_idx = sd->busy_idx; | |
3179 | break; | |
3180 | ||
3181 | case CPU_NEWLY_IDLE: | |
3182 | load_idx = sd->newidle_idx; | |
3183 | break; | |
3184 | default: | |
3185 | load_idx = sd->idle_idx; | |
3186 | break; | |
3187 | } | |
3188 | ||
3189 | return load_idx; | |
3190 | } | |
3191 | ||
3192 | ||
3193 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) | |
3194 | /** | |
3195 | * init_sd_power_savings_stats - Initialize power savings statistics for | |
3196 | * the given sched_domain, during load balancing. | |
3197 | * | |
3198 | * @sd: Sched domain whose power-savings statistics are to be initialized. | |
3199 | * @sds: Variable containing the statistics for sd. | |
3200 | * @idle: Idle status of the CPU at which we're performing load-balancing. | |
3201 | */ | |
3202 | static inline void init_sd_power_savings_stats(struct sched_domain *sd, | |
3203 | struct sd_lb_stats *sds, enum cpu_idle_type idle) | |
3204 | { | |
3205 | /* | |
3206 | * Busy processors will not participate in power savings | |
3207 | * balance. | |
3208 | */ | |
3209 | if (idle == CPU_NOT_IDLE || !(sd->flags & SD_POWERSAVINGS_BALANCE)) | |
3210 | sds->power_savings_balance = 0; | |
3211 | else { | |
3212 | sds->power_savings_balance = 1; | |
3213 | sds->min_nr_running = ULONG_MAX; | |
3214 | sds->leader_nr_running = 0; | |
3215 | } | |
3216 | } | |
3217 | ||
3218 | /** | |
3219 | * update_sd_power_savings_stats - Update the power saving stats for a | |
3220 | * sched_domain while performing load balancing. | |
3221 | * | |
3222 | * @group: sched_group belonging to the sched_domain under consideration. | |
3223 | * @sds: Variable containing the statistics of the sched_domain | |
3224 | * @local_group: Does group contain the CPU for which we're performing | |
3225 | * load balancing ? | |
3226 | * @sgs: Variable containing the statistics of the group. | |
3227 | */ | |
3228 | static inline void update_sd_power_savings_stats(struct sched_group *group, | |
3229 | struct sd_lb_stats *sds, int local_group, struct sg_lb_stats *sgs) | |
3230 | { | |
3231 | ||
3232 | if (!sds->power_savings_balance) | |
3233 | return; | |
3234 | ||
3235 | /* | |
3236 | * If the local group is idle or completely loaded | |
3237 | * no need to do power savings balance at this domain | |
3238 | */ | |
3239 | if (local_group && (sds->this_nr_running >= sgs->group_capacity || | |
3240 | !sds->this_nr_running)) | |
3241 | sds->power_savings_balance = 0; | |
3242 | ||
3243 | /* | |
3244 | * If a group is already running at full capacity or idle, | |
3245 | * don't include that group in power savings calculations | |
3246 | */ | |
3247 | if (!sds->power_savings_balance || | |
3248 | sgs->sum_nr_running >= sgs->group_capacity || | |
3249 | !sgs->sum_nr_running) | |
3250 | return; | |
3251 | ||
3252 | /* | |
3253 | * Calculate the group which has the least non-idle load. | |
3254 | * This is the group from where we need to pick up the load | |
3255 | * for saving power | |
3256 | */ | |
3257 | if ((sgs->sum_nr_running < sds->min_nr_running) || | |
3258 | (sgs->sum_nr_running == sds->min_nr_running && | |
3259 | group_first_cpu(group) > group_first_cpu(sds->group_min))) { | |
3260 | sds->group_min = group; | |
3261 | sds->min_nr_running = sgs->sum_nr_running; | |
3262 | sds->min_load_per_task = sgs->sum_weighted_load / | |
3263 | sgs->sum_nr_running; | |
3264 | } | |
3265 | ||
3266 | /* | |
3267 | * Calculate the group which is almost near its | |
3268 | * capacity but still has some space to pick up some load | |
3269 | * from other group and save more power | |
3270 | */ | |
3271 | if (sgs->sum_nr_running + 1 > sgs->group_capacity) | |
3272 | return; | |
3273 | ||
3274 | if (sgs->sum_nr_running > sds->leader_nr_running || | |
3275 | (sgs->sum_nr_running == sds->leader_nr_running && | |
3276 | group_first_cpu(group) < group_first_cpu(sds->group_leader))) { | |
3277 | sds->group_leader = group; | |
3278 | sds->leader_nr_running = sgs->sum_nr_running; | |
3279 | } | |
3280 | } | |
3281 | ||
3282 | /** | |
3283 | * check_power_save_busiest_group - see if there is potential for some power-savings balance | |
3284 | * @sds: Variable containing the statistics of the sched_domain | |
3285 | * under consideration. | |
3286 | * @this_cpu: Cpu at which we're currently performing load-balancing. | |
3287 | * @imbalance: Variable to store the imbalance. | |
3288 | * | |
3289 | * Description: | |
3290 | * Check if we have potential to perform some power-savings balance. | |
3291 | * If yes, set the busiest group to be the least loaded group in the | |
3292 | * sched_domain, so that it's CPUs can be put to idle. | |
3293 | * | |
3294 | * Returns 1 if there is potential to perform power-savings balance. | |
3295 | * Else returns 0. | |
3296 | */ | |
3297 | static inline int check_power_save_busiest_group(struct sd_lb_stats *sds, | |
3298 | int this_cpu, unsigned long *imbalance) | |
3299 | { | |
3300 | if (!sds->power_savings_balance) | |
3301 | return 0; | |
3302 | ||
3303 | if (sds->this != sds->group_leader || | |
3304 | sds->group_leader == sds->group_min) | |
3305 | return 0; | |
3306 | ||
3307 | *imbalance = sds->min_load_per_task; | |
3308 | sds->busiest = sds->group_min; | |
3309 | ||
3310 | return 1; | |
3311 | ||
3312 | } | |
3313 | #else /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */ | |
3314 | static inline void init_sd_power_savings_stats(struct sched_domain *sd, | |
3315 | struct sd_lb_stats *sds, enum cpu_idle_type idle) | |
3316 | { | |
3317 | return; | |
3318 | } | |
3319 | ||
3320 | static inline void update_sd_power_savings_stats(struct sched_group *group, | |
3321 | struct sd_lb_stats *sds, int local_group, struct sg_lb_stats *sgs) | |
3322 | { | |
3323 | return; | |
3324 | } | |
3325 | ||
3326 | static inline int check_power_save_busiest_group(struct sd_lb_stats *sds, | |
3327 | int this_cpu, unsigned long *imbalance) | |
3328 | { | |
3329 | return 0; | |
3330 | } | |
3331 | #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */ | |
3332 | ||
3333 | ||
3334 | unsigned long default_scale_freq_power(struct sched_domain *sd, int cpu) | |
3335 | { | |
1399fa78 | 3336 | return SCHED_POWER_SCALE; |
1e3c88bd PZ |
3337 | } |
3338 | ||
3339 | unsigned long __weak arch_scale_freq_power(struct sched_domain *sd, int cpu) | |
3340 | { | |
3341 | return default_scale_freq_power(sd, cpu); | |
3342 | } | |
3343 | ||
3344 | unsigned long default_scale_smt_power(struct sched_domain *sd, int cpu) | |
3345 | { | |
669c55e9 | 3346 | unsigned long weight = sd->span_weight; |
1e3c88bd PZ |
3347 | unsigned long smt_gain = sd->smt_gain; |
3348 | ||
3349 | smt_gain /= weight; | |
3350 | ||
3351 | return smt_gain; | |
3352 | } | |
3353 | ||
3354 | unsigned long __weak arch_scale_smt_power(struct sched_domain *sd, int cpu) | |
3355 | { | |
3356 | return default_scale_smt_power(sd, cpu); | |
3357 | } | |
3358 | ||
3359 | unsigned long scale_rt_power(int cpu) | |
3360 | { | |
3361 | struct rq *rq = cpu_rq(cpu); | |
3362 | u64 total, available; | |
3363 | ||
1e3c88bd | 3364 | total = sched_avg_period() + (rq->clock - rq->age_stamp); |
aa483808 VP |
3365 | |
3366 | if (unlikely(total < rq->rt_avg)) { | |
3367 | /* Ensures that power won't end up being negative */ | |
3368 | available = 0; | |
3369 | } else { | |
3370 | available = total - rq->rt_avg; | |
3371 | } | |
1e3c88bd | 3372 | |
1399fa78 NR |
3373 | if (unlikely((s64)total < SCHED_POWER_SCALE)) |
3374 | total = SCHED_POWER_SCALE; | |
1e3c88bd | 3375 | |
1399fa78 | 3376 | total >>= SCHED_POWER_SHIFT; |
1e3c88bd PZ |
3377 | |
3378 | return div_u64(available, total); | |
3379 | } | |
3380 | ||
3381 | static void update_cpu_power(struct sched_domain *sd, int cpu) | |
3382 | { | |
669c55e9 | 3383 | unsigned long weight = sd->span_weight; |
1399fa78 | 3384 | unsigned long power = SCHED_POWER_SCALE; |
1e3c88bd PZ |
3385 | struct sched_group *sdg = sd->groups; |
3386 | ||
1e3c88bd PZ |
3387 | if ((sd->flags & SD_SHARE_CPUPOWER) && weight > 1) { |
3388 | if (sched_feat(ARCH_POWER)) | |
3389 | power *= arch_scale_smt_power(sd, cpu); | |
3390 | else | |
3391 | power *= default_scale_smt_power(sd, cpu); | |
3392 | ||
1399fa78 | 3393 | power >>= SCHED_POWER_SHIFT; |
1e3c88bd PZ |
3394 | } |
3395 | ||
9c3f75cb | 3396 | sdg->sgp->power_orig = power; |
9d5efe05 SV |
3397 | |
3398 | if (sched_feat(ARCH_POWER)) | |
3399 | power *= arch_scale_freq_power(sd, cpu); | |
3400 | else | |
3401 | power *= default_scale_freq_power(sd, cpu); | |
3402 | ||
1399fa78 | 3403 | power >>= SCHED_POWER_SHIFT; |
9d5efe05 | 3404 | |
1e3c88bd | 3405 | power *= scale_rt_power(cpu); |
1399fa78 | 3406 | power >>= SCHED_POWER_SHIFT; |
1e3c88bd PZ |
3407 | |
3408 | if (!power) | |
3409 | power = 1; | |
3410 | ||
e51fd5e2 | 3411 | cpu_rq(cpu)->cpu_power = power; |
9c3f75cb | 3412 | sdg->sgp->power = power; |
1e3c88bd PZ |
3413 | } |
3414 | ||
3415 | static void update_group_power(struct sched_domain *sd, int cpu) | |
3416 | { | |
3417 | struct sched_domain *child = sd->child; | |
3418 | struct sched_group *group, *sdg = sd->groups; | |
3419 | unsigned long power; | |
3420 | ||
3421 | if (!child) { | |
3422 | update_cpu_power(sd, cpu); | |
3423 | return; | |
3424 | } | |
3425 | ||
3426 | power = 0; | |
3427 | ||
3428 | group = child->groups; | |
3429 | do { | |
9c3f75cb | 3430 | power += group->sgp->power; |
1e3c88bd PZ |
3431 | group = group->next; |
3432 | } while (group != child->groups); | |
3433 | ||
9c3f75cb | 3434 | sdg->sgp->power = power; |
1e3c88bd PZ |
3435 | } |
3436 | ||
9d5efe05 SV |
3437 | /* |
3438 | * Try and fix up capacity for tiny siblings, this is needed when | |
3439 | * things like SD_ASYM_PACKING need f_b_g to select another sibling | |
3440 | * which on its own isn't powerful enough. | |
3441 | * | |
3442 | * See update_sd_pick_busiest() and check_asym_packing(). | |
3443 | */ | |
3444 | static inline int | |
3445 | fix_small_capacity(struct sched_domain *sd, struct sched_group *group) | |
3446 | { | |
3447 | /* | |
1399fa78 | 3448 | * Only siblings can have significantly less than SCHED_POWER_SCALE |
9d5efe05 | 3449 | */ |
a6c75f2f | 3450 | if (!(sd->flags & SD_SHARE_CPUPOWER)) |
9d5efe05 SV |
3451 | return 0; |
3452 | ||
3453 | /* | |
3454 | * If ~90% of the cpu_power is still there, we're good. | |
3455 | */ | |
9c3f75cb | 3456 | if (group->sgp->power * 32 > group->sgp->power_orig * 29) |
9d5efe05 SV |
3457 | return 1; |
3458 | ||
3459 | return 0; | |
3460 | } | |
3461 | ||
1e3c88bd PZ |
3462 | /** |
3463 | * update_sg_lb_stats - Update sched_group's statistics for load balancing. | |
3464 | * @sd: The sched_domain whose statistics are to be updated. | |
3465 | * @group: sched_group whose statistics are to be updated. | |
3466 | * @this_cpu: Cpu for which load balance is currently performed. | |
3467 | * @idle: Idle status of this_cpu | |
3468 | * @load_idx: Load index of sched_domain of this_cpu for load calc. | |
1e3c88bd PZ |
3469 | * @local_group: Does group contain this_cpu. |
3470 | * @cpus: Set of cpus considered for load balancing. | |
3471 | * @balance: Should we balance. | |
3472 | * @sgs: variable to hold the statistics for this group. | |
3473 | */ | |
3474 | static inline void update_sg_lb_stats(struct sched_domain *sd, | |
3475 | struct sched_group *group, int this_cpu, | |
46e49b38 | 3476 | enum cpu_idle_type idle, int load_idx, |
1e3c88bd PZ |
3477 | int local_group, const struct cpumask *cpus, |
3478 | int *balance, struct sg_lb_stats *sgs) | |
3479 | { | |
2582f0eb | 3480 | unsigned long load, max_cpu_load, min_cpu_load, max_nr_running; |
1e3c88bd PZ |
3481 | int i; |
3482 | unsigned int balance_cpu = -1, first_idle_cpu = 0; | |
dd5feea1 | 3483 | unsigned long avg_load_per_task = 0; |
1e3c88bd | 3484 | |
871e35bc | 3485 | if (local_group) |
1e3c88bd | 3486 | balance_cpu = group_first_cpu(group); |
1e3c88bd PZ |
3487 | |
3488 | /* Tally up the load of all CPUs in the group */ | |
1e3c88bd PZ |
3489 | max_cpu_load = 0; |
3490 | min_cpu_load = ~0UL; | |
2582f0eb | 3491 | max_nr_running = 0; |
1e3c88bd PZ |
3492 | |
3493 | for_each_cpu_and(i, sched_group_cpus(group), cpus) { | |
3494 | struct rq *rq = cpu_rq(i); | |
3495 | ||
1e3c88bd PZ |
3496 | /* Bias balancing toward cpus of our domain */ |
3497 | if (local_group) { | |
3498 | if (idle_cpu(i) && !first_idle_cpu) { | |
3499 | first_idle_cpu = 1; | |
3500 | balance_cpu = i; | |
3501 | } | |
3502 | ||
3503 | load = target_load(i, load_idx); | |
3504 | } else { | |
3505 | load = source_load(i, load_idx); | |
2582f0eb | 3506 | if (load > max_cpu_load) { |
1e3c88bd | 3507 | max_cpu_load = load; |
2582f0eb NR |
3508 | max_nr_running = rq->nr_running; |
3509 | } | |
1e3c88bd PZ |
3510 | if (min_cpu_load > load) |
3511 | min_cpu_load = load; | |
3512 | } | |
3513 | ||
3514 | sgs->group_load += load; | |
3515 | sgs->sum_nr_running += rq->nr_running; | |
3516 | sgs->sum_weighted_load += weighted_cpuload(i); | |
aae6d3dd SS |
3517 | if (idle_cpu(i)) |
3518 | sgs->idle_cpus++; | |
1e3c88bd PZ |
3519 | } |
3520 | ||
3521 | /* | |
3522 | * First idle cpu or the first cpu(busiest) in this sched group | |
3523 | * is eligible for doing load balancing at this and above | |
3524 | * domains. In the newly idle case, we will allow all the cpu's | |
3525 | * to do the newly idle load balance. | |
3526 | */ | |
bbc8cb5b PZ |
3527 | if (idle != CPU_NEWLY_IDLE && local_group) { |
3528 | if (balance_cpu != this_cpu) { | |
3529 | *balance = 0; | |
3530 | return; | |
3531 | } | |
3532 | update_group_power(sd, this_cpu); | |
1e3c88bd PZ |
3533 | } |
3534 | ||
3535 | /* Adjust by relative CPU power of the group */ | |
9c3f75cb | 3536 | sgs->avg_load = (sgs->group_load*SCHED_POWER_SCALE) / group->sgp->power; |
1e3c88bd | 3537 | |
1e3c88bd PZ |
3538 | /* |
3539 | * Consider the group unbalanced when the imbalance is larger | |
866ab43e | 3540 | * than the average weight of a task. |
1e3c88bd PZ |
3541 | * |
3542 | * APZ: with cgroup the avg task weight can vary wildly and | |
3543 | * might not be a suitable number - should we keep a | |
3544 | * normalized nr_running number somewhere that negates | |
3545 | * the hierarchy? | |
3546 | */ | |
dd5feea1 SS |
3547 | if (sgs->sum_nr_running) |
3548 | avg_load_per_task = sgs->sum_weighted_load / sgs->sum_nr_running; | |
1e3c88bd | 3549 | |
866ab43e | 3550 | if ((max_cpu_load - min_cpu_load) >= avg_load_per_task && max_nr_running > 1) |
1e3c88bd PZ |
3551 | sgs->group_imb = 1; |
3552 | ||
9c3f75cb | 3553 | sgs->group_capacity = DIV_ROUND_CLOSEST(group->sgp->power, |
1399fa78 | 3554 | SCHED_POWER_SCALE); |
9d5efe05 SV |
3555 | if (!sgs->group_capacity) |
3556 | sgs->group_capacity = fix_small_capacity(sd, group); | |
aae6d3dd | 3557 | sgs->group_weight = group->group_weight; |
fab47622 NR |
3558 | |
3559 | if (sgs->group_capacity > sgs->sum_nr_running) | |
3560 | sgs->group_has_capacity = 1; | |
1e3c88bd PZ |
3561 | } |
3562 | ||
532cb4c4 MN |
3563 | /** |
3564 | * update_sd_pick_busiest - return 1 on busiest group | |
3565 | * @sd: sched_domain whose statistics are to be checked | |
3566 | * @sds: sched_domain statistics | |
3567 | * @sg: sched_group candidate to be checked for being the busiest | |
b6b12294 MN |
3568 | * @sgs: sched_group statistics |
3569 | * @this_cpu: the current cpu | |
532cb4c4 MN |
3570 | * |
3571 | * Determine if @sg is a busier group than the previously selected | |
3572 | * busiest group. | |
3573 | */ | |
3574 | static bool update_sd_pick_busiest(struct sched_domain *sd, | |
3575 | struct sd_lb_stats *sds, | |
3576 | struct sched_group *sg, | |
3577 | struct sg_lb_stats *sgs, | |
3578 | int this_cpu) | |
3579 | { | |
3580 | if (sgs->avg_load <= sds->max_load) | |
3581 | return false; | |
3582 | ||
3583 | if (sgs->sum_nr_running > sgs->group_capacity) | |
3584 | return true; | |
3585 | ||
3586 | if (sgs->group_imb) | |
3587 | return true; | |
3588 | ||
3589 | /* | |
3590 | * ASYM_PACKING needs to move all the work to the lowest | |
3591 | * numbered CPUs in the group, therefore mark all groups | |
3592 | * higher than ourself as busy. | |
3593 | */ | |
3594 | if ((sd->flags & SD_ASYM_PACKING) && sgs->sum_nr_running && | |
3595 | this_cpu < group_first_cpu(sg)) { | |
3596 | if (!sds->busiest) | |
3597 | return true; | |
3598 | ||
3599 | if (group_first_cpu(sds->busiest) > group_first_cpu(sg)) | |
3600 | return true; | |
3601 | } | |
3602 | ||
3603 | return false; | |
3604 | } | |
3605 | ||
1e3c88bd | 3606 | /** |
461819ac | 3607 | * update_sd_lb_stats - Update sched_domain's statistics for load balancing. |
1e3c88bd PZ |
3608 | * @sd: sched_domain whose statistics are to be updated. |
3609 | * @this_cpu: Cpu for which load balance is currently performed. | |
3610 | * @idle: Idle status of this_cpu | |
1e3c88bd PZ |
3611 | * @cpus: Set of cpus considered for load balancing. |
3612 | * @balance: Should we balance. | |
3613 | * @sds: variable to hold the statistics for this sched_domain. | |
3614 | */ | |
3615 | static inline void update_sd_lb_stats(struct sched_domain *sd, int this_cpu, | |
46e49b38 VP |
3616 | enum cpu_idle_type idle, const struct cpumask *cpus, |
3617 | int *balance, struct sd_lb_stats *sds) | |
1e3c88bd PZ |
3618 | { |
3619 | struct sched_domain *child = sd->child; | |
532cb4c4 | 3620 | struct sched_group *sg = sd->groups; |
1e3c88bd PZ |
3621 | struct sg_lb_stats sgs; |
3622 | int load_idx, prefer_sibling = 0; | |
3623 | ||
3624 | if (child && child->flags & SD_PREFER_SIBLING) | |
3625 | prefer_sibling = 1; | |
3626 | ||
3627 | init_sd_power_savings_stats(sd, sds, idle); | |
3628 | load_idx = get_sd_load_idx(sd, idle); | |
3629 | ||
3630 | do { | |
3631 | int local_group; | |
3632 | ||
532cb4c4 | 3633 | local_group = cpumask_test_cpu(this_cpu, sched_group_cpus(sg)); |
1e3c88bd | 3634 | memset(&sgs, 0, sizeof(sgs)); |
46e49b38 | 3635 | update_sg_lb_stats(sd, sg, this_cpu, idle, load_idx, |
1e3c88bd PZ |
3636 | local_group, cpus, balance, &sgs); |
3637 | ||
8f190fb3 | 3638 | if (local_group && !(*balance)) |
1e3c88bd PZ |
3639 | return; |
3640 | ||
3641 | sds->total_load += sgs.group_load; | |
9c3f75cb | 3642 | sds->total_pwr += sg->sgp->power; |
1e3c88bd PZ |
3643 | |
3644 | /* | |
3645 | * In case the child domain prefers tasks go to siblings | |
532cb4c4 | 3646 | * first, lower the sg capacity to one so that we'll try |
75dd321d NR |
3647 | * and move all the excess tasks away. We lower the capacity |
3648 | * of a group only if the local group has the capacity to fit | |
3649 | * these excess tasks, i.e. nr_running < group_capacity. The | |
3650 | * extra check prevents the case where you always pull from the | |
3651 | * heaviest group when it is already under-utilized (possible | |
3652 | * with a large weight task outweighs the tasks on the system). | |
1e3c88bd | 3653 | */ |
75dd321d | 3654 | if (prefer_sibling && !local_group && sds->this_has_capacity) |
1e3c88bd PZ |
3655 | sgs.group_capacity = min(sgs.group_capacity, 1UL); |
3656 | ||
3657 | if (local_group) { | |
3658 | sds->this_load = sgs.avg_load; | |
532cb4c4 | 3659 | sds->this = sg; |
1e3c88bd PZ |
3660 | sds->this_nr_running = sgs.sum_nr_running; |
3661 | sds->this_load_per_task = sgs.sum_weighted_load; | |
fab47622 | 3662 | sds->this_has_capacity = sgs.group_has_capacity; |
aae6d3dd | 3663 | sds->this_idle_cpus = sgs.idle_cpus; |
532cb4c4 | 3664 | } else if (update_sd_pick_busiest(sd, sds, sg, &sgs, this_cpu)) { |
1e3c88bd | 3665 | sds->max_load = sgs.avg_load; |
532cb4c4 | 3666 | sds->busiest = sg; |
1e3c88bd | 3667 | sds->busiest_nr_running = sgs.sum_nr_running; |
aae6d3dd | 3668 | sds->busiest_idle_cpus = sgs.idle_cpus; |
dd5feea1 | 3669 | sds->busiest_group_capacity = sgs.group_capacity; |
1e3c88bd | 3670 | sds->busiest_load_per_task = sgs.sum_weighted_load; |
fab47622 | 3671 | sds->busiest_has_capacity = sgs.group_has_capacity; |
aae6d3dd | 3672 | sds->busiest_group_weight = sgs.group_weight; |
1e3c88bd PZ |
3673 | sds->group_imb = sgs.group_imb; |
3674 | } | |
3675 | ||
532cb4c4 MN |
3676 | update_sd_power_savings_stats(sg, sds, local_group, &sgs); |
3677 | sg = sg->next; | |
3678 | } while (sg != sd->groups); | |
3679 | } | |
3680 | ||
2ec57d44 | 3681 | int __weak arch_sd_sibling_asym_packing(void) |
532cb4c4 MN |
3682 | { |
3683 | return 0*SD_ASYM_PACKING; | |
3684 | } | |
3685 | ||
3686 | /** | |
3687 | * check_asym_packing - Check to see if the group is packed into the | |
3688 | * sched doman. | |
3689 | * | |
3690 | * This is primarily intended to used at the sibling level. Some | |
3691 | * cores like POWER7 prefer to use lower numbered SMT threads. In the | |
3692 | * case of POWER7, it can move to lower SMT modes only when higher | |
3693 | * threads are idle. When in lower SMT modes, the threads will | |
3694 | * perform better since they share less core resources. Hence when we | |
3695 | * have idle threads, we want them to be the higher ones. | |
3696 | * | |
3697 | * This packing function is run on idle threads. It checks to see if | |
3698 | * the busiest CPU in this domain (core in the P7 case) has a higher | |
3699 | * CPU number than the packing function is being run on. Here we are | |
3700 | * assuming lower CPU number will be equivalent to lower a SMT thread | |
3701 | * number. | |
3702 | * | |
b6b12294 MN |
3703 | * Returns 1 when packing is required and a task should be moved to |
3704 | * this CPU. The amount of the imbalance is returned in *imbalance. | |
3705 | * | |
532cb4c4 MN |
3706 | * @sd: The sched_domain whose packing is to be checked. |
3707 | * @sds: Statistics of the sched_domain which is to be packed | |
3708 | * @this_cpu: The cpu at whose sched_domain we're performing load-balance. | |
3709 | * @imbalance: returns amount of imbalanced due to packing. | |
532cb4c4 MN |
3710 | */ |
3711 | static int check_asym_packing(struct sched_domain *sd, | |
3712 | struct sd_lb_stats *sds, | |
3713 | int this_cpu, unsigned long *imbalance) | |
3714 | { | |
3715 | int busiest_cpu; | |
3716 | ||
3717 | if (!(sd->flags & SD_ASYM_PACKING)) | |
3718 | return 0; | |
3719 | ||
3720 | if (!sds->busiest) | |
3721 | return 0; | |
3722 | ||
3723 | busiest_cpu = group_first_cpu(sds->busiest); | |
3724 | if (this_cpu > busiest_cpu) | |
3725 | return 0; | |
3726 | ||
9c3f75cb | 3727 | *imbalance = DIV_ROUND_CLOSEST(sds->max_load * sds->busiest->sgp->power, |
1399fa78 | 3728 | SCHED_POWER_SCALE); |
532cb4c4 | 3729 | return 1; |
1e3c88bd PZ |
3730 | } |
3731 | ||
3732 | /** | |
3733 | * fix_small_imbalance - Calculate the minor imbalance that exists | |
3734 | * amongst the groups of a sched_domain, during | |
3735 | * load balancing. | |
3736 | * @sds: Statistics of the sched_domain whose imbalance is to be calculated. | |
3737 | * @this_cpu: The cpu at whose sched_domain we're performing load-balance. | |
3738 | * @imbalance: Variable to store the imbalance. | |
3739 | */ | |
3740 | static inline void fix_small_imbalance(struct sd_lb_stats *sds, | |
3741 | int this_cpu, unsigned long *imbalance) | |
3742 | { | |
3743 | unsigned long tmp, pwr_now = 0, pwr_move = 0; | |
3744 | unsigned int imbn = 2; | |
dd5feea1 | 3745 | unsigned long scaled_busy_load_per_task; |
1e3c88bd PZ |
3746 | |
3747 | if (sds->this_nr_running) { | |
3748 | sds->this_load_per_task /= sds->this_nr_running; | |
3749 | if (sds->busiest_load_per_task > | |
3750 | sds->this_load_per_task) | |
3751 | imbn = 1; | |
3752 | } else | |
3753 | sds->this_load_per_task = | |
3754 | cpu_avg_load_per_task(this_cpu); | |
3755 | ||
dd5feea1 | 3756 | scaled_busy_load_per_task = sds->busiest_load_per_task |
1399fa78 | 3757 | * SCHED_POWER_SCALE; |
9c3f75cb | 3758 | scaled_busy_load_per_task /= sds->busiest->sgp->power; |
dd5feea1 SS |
3759 | |
3760 | if (sds->max_load - sds->this_load + scaled_busy_load_per_task >= | |
3761 | (scaled_busy_load_per_task * imbn)) { | |
1e3c88bd PZ |
3762 | *imbalance = sds->busiest_load_per_task; |
3763 | return; | |
3764 | } | |
3765 | ||
3766 | /* | |
3767 | * OK, we don't have enough imbalance to justify moving tasks, | |
3768 | * however we may be able to increase total CPU power used by | |
3769 | * moving them. | |
3770 | */ | |
3771 | ||
9c3f75cb | 3772 | pwr_now += sds->busiest->sgp->power * |
1e3c88bd | 3773 | min(sds->busiest_load_per_task, sds->max_load); |
9c3f75cb | 3774 | pwr_now += sds->this->sgp->power * |
1e3c88bd | 3775 | min(sds->this_load_per_task, sds->this_load); |
1399fa78 | 3776 | pwr_now /= SCHED_POWER_SCALE; |
1e3c88bd PZ |
3777 | |
3778 | /* Amount of load we'd subtract */ | |
1399fa78 | 3779 | tmp = (sds->busiest_load_per_task * SCHED_POWER_SCALE) / |
9c3f75cb | 3780 | sds->busiest->sgp->power; |
1e3c88bd | 3781 | if (sds->max_load > tmp) |
9c3f75cb | 3782 | pwr_move += sds->busiest->sgp->power * |
1e3c88bd PZ |
3783 | min(sds->busiest_load_per_task, sds->max_load - tmp); |
3784 | ||
3785 | /* Amount of load we'd add */ | |
9c3f75cb | 3786 | if (sds->max_load * sds->busiest->sgp->power < |
1399fa78 | 3787 | sds->busiest_load_per_task * SCHED_POWER_SCALE) |
9c3f75cb PZ |
3788 | tmp = (sds->max_load * sds->busiest->sgp->power) / |
3789 | sds->this->sgp->power; | |
1e3c88bd | 3790 | else |
1399fa78 | 3791 | tmp = (sds->busiest_load_per_task * SCHED_POWER_SCALE) / |
9c3f75cb PZ |
3792 | sds->this->sgp->power; |
3793 | pwr_move += sds->this->sgp->power * | |
1e3c88bd | 3794 | min(sds->this_load_per_task, sds->this_load + tmp); |
1399fa78 | 3795 | pwr_move /= SCHED_POWER_SCALE; |
1e3c88bd PZ |
3796 | |
3797 | /* Move if we gain throughput */ | |
3798 | if (pwr_move > pwr_now) | |
3799 | *imbalance = sds->busiest_load_per_task; | |
3800 | } | |
3801 | ||
3802 | /** | |
3803 | * calculate_imbalance - Calculate the amount of imbalance present within the | |
3804 | * groups of a given sched_domain during load balance. | |
3805 | * @sds: statistics of the sched_domain whose imbalance is to be calculated. | |
3806 | * @this_cpu: Cpu for which currently load balance is being performed. | |
3807 | * @imbalance: The variable to store the imbalance. | |
3808 | */ | |
3809 | static inline void calculate_imbalance(struct sd_lb_stats *sds, int this_cpu, | |
3810 | unsigned long *imbalance) | |
3811 | { | |
dd5feea1 SS |
3812 | unsigned long max_pull, load_above_capacity = ~0UL; |
3813 | ||
3814 | sds->busiest_load_per_task /= sds->busiest_nr_running; | |
3815 | if (sds->group_imb) { | |
3816 | sds->busiest_load_per_task = | |
3817 | min(sds->busiest_load_per_task, sds->avg_load); | |
3818 | } | |
3819 | ||
1e3c88bd PZ |
3820 | /* |
3821 | * In the presence of smp nice balancing, certain scenarios can have | |
3822 | * max load less than avg load(as we skip the groups at or below | |
3823 | * its cpu_power, while calculating max_load..) | |
3824 | */ | |
3825 | if (sds->max_load < sds->avg_load) { | |
3826 | *imbalance = 0; | |
3827 | return fix_small_imbalance(sds, this_cpu, imbalance); | |
3828 | } | |
3829 | ||
dd5feea1 SS |
3830 | if (!sds->group_imb) { |
3831 | /* | |
3832 | * Don't want to pull so many tasks that a group would go idle. | |
3833 | */ | |
3834 | load_above_capacity = (sds->busiest_nr_running - | |
3835 | sds->busiest_group_capacity); | |
3836 | ||
1399fa78 | 3837 | load_above_capacity *= (SCHED_LOAD_SCALE * SCHED_POWER_SCALE); |
dd5feea1 | 3838 | |
9c3f75cb | 3839 | load_above_capacity /= sds->busiest->sgp->power; |
dd5feea1 SS |
3840 | } |
3841 | ||
3842 | /* | |
3843 | * We're trying to get all the cpus to the average_load, so we don't | |
3844 | * want to push ourselves above the average load, nor do we wish to | |
3845 | * reduce the max loaded cpu below the average load. At the same time, | |
3846 | * we also don't want to reduce the group load below the group capacity | |
3847 | * (so that we can implement power-savings policies etc). Thus we look | |
3848 | * for the minimum possible imbalance. | |
3849 | * Be careful of negative numbers as they'll appear as very large values | |
3850 | * with unsigned longs. | |
3851 | */ | |
3852 | max_pull = min(sds->max_load - sds->avg_load, load_above_capacity); | |
1e3c88bd PZ |
3853 | |
3854 | /* How much load to actually move to equalise the imbalance */ | |
9c3f75cb PZ |
3855 | *imbalance = min(max_pull * sds->busiest->sgp->power, |
3856 | (sds->avg_load - sds->this_load) * sds->this->sgp->power) | |
1399fa78 | 3857 | / SCHED_POWER_SCALE; |
1e3c88bd PZ |
3858 | |
3859 | /* | |
3860 | * if *imbalance is less than the average load per runnable task | |
25985edc | 3861 | * there is no guarantee that any tasks will be moved so we'll have |
1e3c88bd PZ |
3862 | * a think about bumping its value to force at least one task to be |
3863 | * moved | |
3864 | */ | |
3865 | if (*imbalance < sds->busiest_load_per_task) | |
3866 | return fix_small_imbalance(sds, this_cpu, imbalance); | |
3867 | ||
3868 | } | |
fab47622 | 3869 | |
1e3c88bd PZ |
3870 | /******* find_busiest_group() helpers end here *********************/ |
3871 | ||
3872 | /** | |
3873 | * find_busiest_group - Returns the busiest group within the sched_domain | |
3874 | * if there is an imbalance. If there isn't an imbalance, and | |
3875 | * the user has opted for power-savings, it returns a group whose | |
3876 | * CPUs can be put to idle by rebalancing those tasks elsewhere, if | |
3877 | * such a group exists. | |
3878 | * | |
3879 | * Also calculates the amount of weighted load which should be moved | |
3880 | * to restore balance. | |
3881 | * | |
3882 | * @sd: The sched_domain whose busiest group is to be returned. | |
3883 | * @this_cpu: The cpu for which load balancing is currently being performed. | |
3884 | * @imbalance: Variable which stores amount of weighted load which should | |
3885 | * be moved to restore balance/put a group to idle. | |
3886 | * @idle: The idle status of this_cpu. | |
1e3c88bd PZ |
3887 | * @cpus: The set of CPUs under consideration for load-balancing. |
3888 | * @balance: Pointer to a variable indicating if this_cpu | |
3889 | * is the appropriate cpu to perform load balancing at this_level. | |
3890 | * | |
3891 | * Returns: - the busiest group if imbalance exists. | |
3892 | * - If no imbalance and user has opted for power-savings balance, | |
3893 | * return the least loaded group whose CPUs can be | |
3894 | * put to idle by rebalancing its tasks onto our group. | |
3895 | */ | |
3896 | static struct sched_group * | |
3897 | find_busiest_group(struct sched_domain *sd, int this_cpu, | |
3898 | unsigned long *imbalance, enum cpu_idle_type idle, | |
46e49b38 | 3899 | const struct cpumask *cpus, int *balance) |
1e3c88bd PZ |
3900 | { |
3901 | struct sd_lb_stats sds; | |
3902 | ||
3903 | memset(&sds, 0, sizeof(sds)); | |
3904 | ||
3905 | /* | |
3906 | * Compute the various statistics relavent for load balancing at | |
3907 | * this level. | |
3908 | */ | |
46e49b38 | 3909 | update_sd_lb_stats(sd, this_cpu, idle, cpus, balance, &sds); |
1e3c88bd | 3910 | |
cc57aa8f PZ |
3911 | /* |
3912 | * this_cpu is not the appropriate cpu to perform load balancing at | |
3913 | * this level. | |
1e3c88bd | 3914 | */ |
8f190fb3 | 3915 | if (!(*balance)) |
1e3c88bd PZ |
3916 | goto ret; |
3917 | ||
532cb4c4 MN |
3918 | if ((idle == CPU_IDLE || idle == CPU_NEWLY_IDLE) && |
3919 | check_asym_packing(sd, &sds, this_cpu, imbalance)) | |
3920 | return sds.busiest; | |
3921 | ||
cc57aa8f | 3922 | /* There is no busy sibling group to pull tasks from */ |
1e3c88bd PZ |
3923 | if (!sds.busiest || sds.busiest_nr_running == 0) |
3924 | goto out_balanced; | |
3925 | ||
1399fa78 | 3926 | sds.avg_load = (SCHED_POWER_SCALE * sds.total_load) / sds.total_pwr; |
b0432d8f | 3927 | |
866ab43e PZ |
3928 | /* |
3929 | * If the busiest group is imbalanced the below checks don't | |
3930 | * work because they assumes all things are equal, which typically | |
3931 | * isn't true due to cpus_allowed constraints and the like. | |
3932 | */ | |
3933 | if (sds.group_imb) | |
3934 | goto force_balance; | |
3935 | ||
cc57aa8f | 3936 | /* SD_BALANCE_NEWIDLE trumps SMP nice when underutilized */ |
fab47622 NR |
3937 | if (idle == CPU_NEWLY_IDLE && sds.this_has_capacity && |
3938 | !sds.busiest_has_capacity) | |
3939 | goto force_balance; | |
3940 | ||
cc57aa8f PZ |
3941 | /* |
3942 | * If the local group is more busy than the selected busiest group | |
3943 | * don't try and pull any tasks. | |
3944 | */ | |
1e3c88bd PZ |
3945 | if (sds.this_load >= sds.max_load) |
3946 | goto out_balanced; | |
3947 | ||
cc57aa8f PZ |
3948 | /* |
3949 | * Don't pull any tasks if this group is already above the domain | |
3950 | * average load. | |
3951 | */ | |
1e3c88bd PZ |
3952 | if (sds.this_load >= sds.avg_load) |
3953 | goto out_balanced; | |
3954 | ||
c186fafe | 3955 | if (idle == CPU_IDLE) { |
aae6d3dd SS |
3956 | /* |
3957 | * This cpu is idle. If the busiest group load doesn't | |
3958 | * have more tasks than the number of available cpu's and | |
3959 | * there is no imbalance between this and busiest group | |
3960 | * wrt to idle cpu's, it is balanced. | |
3961 | */ | |
c186fafe | 3962 | if ((sds.this_idle_cpus <= sds.busiest_idle_cpus + 1) && |
aae6d3dd SS |
3963 | sds.busiest_nr_running <= sds.busiest_group_weight) |
3964 | goto out_balanced; | |
c186fafe PZ |
3965 | } else { |
3966 | /* | |
3967 | * In the CPU_NEWLY_IDLE, CPU_NOT_IDLE cases, use | |
3968 | * imbalance_pct to be conservative. | |
3969 | */ | |
3970 | if (100 * sds.max_load <= sd->imbalance_pct * sds.this_load) | |
3971 | goto out_balanced; | |
aae6d3dd | 3972 | } |
1e3c88bd | 3973 | |
fab47622 | 3974 | force_balance: |
1e3c88bd PZ |
3975 | /* Looks like there is an imbalance. Compute it */ |
3976 | calculate_imbalance(&sds, this_cpu, imbalance); | |
3977 | return sds.busiest; | |
3978 | ||
3979 | out_balanced: | |
3980 | /* | |
3981 | * There is no obvious imbalance. But check if we can do some balancing | |
3982 | * to save power. | |
3983 | */ | |
3984 | if (check_power_save_busiest_group(&sds, this_cpu, imbalance)) | |
3985 | return sds.busiest; | |
3986 | ret: | |
3987 | *imbalance = 0; | |
3988 | return NULL; | |
3989 | } | |
3990 | ||
3991 | /* | |
3992 | * find_busiest_queue - find the busiest runqueue among the cpus in group. | |
3993 | */ | |
3994 | static struct rq * | |
9d5efe05 SV |
3995 | find_busiest_queue(struct sched_domain *sd, struct sched_group *group, |
3996 | enum cpu_idle_type idle, unsigned long imbalance, | |
3997 | const struct cpumask *cpus) | |
1e3c88bd PZ |
3998 | { |
3999 | struct rq *busiest = NULL, *rq; | |
4000 | unsigned long max_load = 0; | |
4001 | int i; | |
4002 | ||
4003 | for_each_cpu(i, sched_group_cpus(group)) { | |
4004 | unsigned long power = power_of(i); | |
1399fa78 NR |
4005 | unsigned long capacity = DIV_ROUND_CLOSEST(power, |
4006 | SCHED_POWER_SCALE); | |
1e3c88bd PZ |
4007 | unsigned long wl; |
4008 | ||
9d5efe05 SV |
4009 | if (!capacity) |
4010 | capacity = fix_small_capacity(sd, group); | |
4011 | ||
1e3c88bd PZ |
4012 | if (!cpumask_test_cpu(i, cpus)) |
4013 | continue; | |
4014 | ||
4015 | rq = cpu_rq(i); | |
6e40f5bb | 4016 | wl = weighted_cpuload(i); |
1e3c88bd | 4017 | |
6e40f5bb TG |
4018 | /* |
4019 | * When comparing with imbalance, use weighted_cpuload() | |
4020 | * which is not scaled with the cpu power. | |
4021 | */ | |
1e3c88bd PZ |
4022 | if (capacity && rq->nr_running == 1 && wl > imbalance) |
4023 | continue; | |
4024 | ||
6e40f5bb TG |
4025 | /* |
4026 | * For the load comparisons with the other cpu's, consider | |
4027 | * the weighted_cpuload() scaled with the cpu power, so that | |
4028 | * the load can be moved away from the cpu that is potentially | |
4029 | * running at a lower capacity. | |
4030 | */ | |
1399fa78 | 4031 | wl = (wl * SCHED_POWER_SCALE) / power; |
6e40f5bb | 4032 | |
1e3c88bd PZ |
4033 | if (wl > max_load) { |
4034 | max_load = wl; | |
4035 | busiest = rq; | |
4036 | } | |
4037 | } | |
4038 | ||
4039 | return busiest; | |
4040 | } | |
4041 | ||
4042 | /* | |
4043 | * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but | |
4044 | * so long as it is large enough. | |
4045 | */ | |
4046 | #define MAX_PINNED_INTERVAL 512 | |
4047 | ||
4048 | /* Working cpumask for load_balance and load_balance_newidle. */ | |
4049 | static DEFINE_PER_CPU(cpumask_var_t, load_balance_tmpmask); | |
4050 | ||
46e49b38 | 4051 | static int need_active_balance(struct sched_domain *sd, int idle, |
532cb4c4 | 4052 | int busiest_cpu, int this_cpu) |
1af3ed3d PZ |
4053 | { |
4054 | if (idle == CPU_NEWLY_IDLE) { | |
532cb4c4 MN |
4055 | |
4056 | /* | |
4057 | * ASYM_PACKING needs to force migrate tasks from busy but | |
4058 | * higher numbered CPUs in order to pack all tasks in the | |
4059 | * lowest numbered CPUs. | |
4060 | */ | |
4061 | if ((sd->flags & SD_ASYM_PACKING) && busiest_cpu > this_cpu) | |
4062 | return 1; | |
4063 | ||
1af3ed3d PZ |
4064 | /* |
4065 | * The only task running in a non-idle cpu can be moved to this | |
4066 | * cpu in an attempt to completely freeup the other CPU | |
4067 | * package. | |
4068 | * | |
4069 | * The package power saving logic comes from | |
4070 | * find_busiest_group(). If there are no imbalance, then | |
4071 | * f_b_g() will return NULL. However when sched_mc={1,2} then | |
4072 | * f_b_g() will select a group from which a running task may be | |
4073 | * pulled to this cpu in order to make the other package idle. | |
4074 | * If there is no opportunity to make a package idle and if | |
4075 | * there are no imbalance, then f_b_g() will return NULL and no | |
4076 | * action will be taken in load_balance_newidle(). | |
4077 | * | |
4078 | * Under normal task pull operation due to imbalance, there | |
4079 | * will be more than one task in the source run queue and | |
4080 | * move_tasks() will succeed. ld_moved will be true and this | |
4081 | * active balance code will not be triggered. | |
4082 | */ | |
1af3ed3d PZ |
4083 | if (sched_mc_power_savings < POWERSAVINGS_BALANCE_WAKEUP) |
4084 | return 0; | |
4085 | } | |
4086 | ||
4087 | return unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2); | |
4088 | } | |
4089 | ||
969c7921 TH |
4090 | static int active_load_balance_cpu_stop(void *data); |
4091 | ||
1e3c88bd PZ |
4092 | /* |
4093 | * Check this_cpu to ensure it is balanced within domain. Attempt to move | |
4094 | * tasks if there is an imbalance. | |
4095 | */ | |
4096 | static int load_balance(int this_cpu, struct rq *this_rq, | |
4097 | struct sched_domain *sd, enum cpu_idle_type idle, | |
4098 | int *balance) | |
4099 | { | |
46e49b38 | 4100 | int ld_moved, all_pinned = 0, active_balance = 0; |
1e3c88bd PZ |
4101 | struct sched_group *group; |
4102 | unsigned long imbalance; | |
4103 | struct rq *busiest; | |
4104 | unsigned long flags; | |
4105 | struct cpumask *cpus = __get_cpu_var(load_balance_tmpmask); | |
4106 | ||
4107 | cpumask_copy(cpus, cpu_active_mask); | |
4108 | ||
1e3c88bd PZ |
4109 | schedstat_inc(sd, lb_count[idle]); |
4110 | ||
4111 | redo: | |
46e49b38 | 4112 | group = find_busiest_group(sd, this_cpu, &imbalance, idle, |
1e3c88bd PZ |
4113 | cpus, balance); |
4114 | ||
4115 | if (*balance == 0) | |
4116 | goto out_balanced; | |
4117 | ||
4118 | if (!group) { | |
4119 | schedstat_inc(sd, lb_nobusyg[idle]); | |
4120 | goto out_balanced; | |
4121 | } | |
4122 | ||
9d5efe05 | 4123 | busiest = find_busiest_queue(sd, group, idle, imbalance, cpus); |
1e3c88bd PZ |
4124 | if (!busiest) { |
4125 | schedstat_inc(sd, lb_nobusyq[idle]); | |
4126 | goto out_balanced; | |
4127 | } | |
4128 | ||
4129 | BUG_ON(busiest == this_rq); | |
4130 | ||
4131 | schedstat_add(sd, lb_imbalance[idle], imbalance); | |
4132 | ||
4133 | ld_moved = 0; | |
4134 | if (busiest->nr_running > 1) { | |
4135 | /* | |
4136 | * Attempt to move tasks. If find_busiest_group has found | |
4137 | * an imbalance but busiest->nr_running <= 1, the group is | |
4138 | * still unbalanced. ld_moved simply stays zero, so it is | |
4139 | * correctly treated as an imbalance. | |
4140 | */ | |
b30aef17 | 4141 | all_pinned = 1; |
1e3c88bd PZ |
4142 | local_irq_save(flags); |
4143 | double_rq_lock(this_rq, busiest); | |
4144 | ld_moved = move_tasks(this_rq, this_cpu, busiest, | |
4145 | imbalance, sd, idle, &all_pinned); | |
4146 | double_rq_unlock(this_rq, busiest); | |
4147 | local_irq_restore(flags); | |
4148 | ||
4149 | /* | |
4150 | * some other cpu did the load balance for us. | |
4151 | */ | |
4152 | if (ld_moved && this_cpu != smp_processor_id()) | |
4153 | resched_cpu(this_cpu); | |
4154 | ||
4155 | /* All tasks on this runqueue were pinned by CPU affinity */ | |
4156 | if (unlikely(all_pinned)) { | |
4157 | cpumask_clear_cpu(cpu_of(busiest), cpus); | |
4158 | if (!cpumask_empty(cpus)) | |
4159 | goto redo; | |
4160 | goto out_balanced; | |
4161 | } | |
4162 | } | |
4163 | ||
4164 | if (!ld_moved) { | |
4165 | schedstat_inc(sd, lb_failed[idle]); | |
58b26c4c VP |
4166 | /* |
4167 | * Increment the failure counter only on periodic balance. | |
4168 | * We do not want newidle balance, which can be very | |
4169 | * frequent, pollute the failure counter causing | |
4170 | * excessive cache_hot migrations and active balances. | |
4171 | */ | |
4172 | if (idle != CPU_NEWLY_IDLE) | |
4173 | sd->nr_balance_failed++; | |
1e3c88bd | 4174 | |
46e49b38 | 4175 | if (need_active_balance(sd, idle, cpu_of(busiest), this_cpu)) { |
1e3c88bd PZ |
4176 | raw_spin_lock_irqsave(&busiest->lock, flags); |
4177 | ||
969c7921 TH |
4178 | /* don't kick the active_load_balance_cpu_stop, |
4179 | * if the curr task on busiest cpu can't be | |
4180 | * moved to this_cpu | |
1e3c88bd PZ |
4181 | */ |
4182 | if (!cpumask_test_cpu(this_cpu, | |
fa17b507 | 4183 | tsk_cpus_allowed(busiest->curr))) { |
1e3c88bd PZ |
4184 | raw_spin_unlock_irqrestore(&busiest->lock, |
4185 | flags); | |
4186 | all_pinned = 1; | |
4187 | goto out_one_pinned; | |
4188 | } | |
4189 | ||
969c7921 TH |
4190 | /* |
4191 | * ->active_balance synchronizes accesses to | |
4192 | * ->active_balance_work. Once set, it's cleared | |
4193 | * only after active load balance is finished. | |
4194 | */ | |
1e3c88bd PZ |
4195 | if (!busiest->active_balance) { |
4196 | busiest->active_balance = 1; | |
4197 | busiest->push_cpu = this_cpu; | |
4198 | active_balance = 1; | |
4199 | } | |
4200 | raw_spin_unlock_irqrestore(&busiest->lock, flags); | |
969c7921 | 4201 | |
1e3c88bd | 4202 | if (active_balance) |
969c7921 TH |
4203 | stop_one_cpu_nowait(cpu_of(busiest), |
4204 | active_load_balance_cpu_stop, busiest, | |
4205 | &busiest->active_balance_work); | |
1e3c88bd PZ |
4206 | |
4207 | /* | |
4208 | * We've kicked active balancing, reset the failure | |
4209 | * counter. | |
4210 | */ | |
4211 | sd->nr_balance_failed = sd->cache_nice_tries+1; | |
4212 | } | |
4213 | } else | |
4214 | sd->nr_balance_failed = 0; | |
4215 | ||
4216 | if (likely(!active_balance)) { | |
4217 | /* We were unbalanced, so reset the balancing interval */ | |
4218 | sd->balance_interval = sd->min_interval; | |
4219 | } else { | |
4220 | /* | |
4221 | * If we've begun active balancing, start to back off. This | |
4222 | * case may not be covered by the all_pinned logic if there | |
4223 | * is only 1 task on the busy runqueue (because we don't call | |
4224 | * move_tasks). | |
4225 | */ | |
4226 | if (sd->balance_interval < sd->max_interval) | |
4227 | sd->balance_interval *= 2; | |
4228 | } | |
4229 | ||
1e3c88bd PZ |
4230 | goto out; |
4231 | ||
4232 | out_balanced: | |
4233 | schedstat_inc(sd, lb_balanced[idle]); | |
4234 | ||
4235 | sd->nr_balance_failed = 0; | |
4236 | ||
4237 | out_one_pinned: | |
4238 | /* tune up the balancing interval */ | |
4239 | if ((all_pinned && sd->balance_interval < MAX_PINNED_INTERVAL) || | |
4240 | (sd->balance_interval < sd->max_interval)) | |
4241 | sd->balance_interval *= 2; | |
4242 | ||
46e49b38 | 4243 | ld_moved = 0; |
1e3c88bd | 4244 | out: |
1e3c88bd PZ |
4245 | return ld_moved; |
4246 | } | |
4247 | ||
1e3c88bd PZ |
4248 | /* |
4249 | * idle_balance is called by schedule() if this_cpu is about to become | |
4250 | * idle. Attempts to pull tasks from other CPUs. | |
4251 | */ | |
4252 | static void idle_balance(int this_cpu, struct rq *this_rq) | |
4253 | { | |
4254 | struct sched_domain *sd; | |
4255 | int pulled_task = 0; | |
4256 | unsigned long next_balance = jiffies + HZ; | |
4257 | ||
4258 | this_rq->idle_stamp = this_rq->clock; | |
4259 | ||
4260 | if (this_rq->avg_idle < sysctl_sched_migration_cost) | |
4261 | return; | |
4262 | ||
f492e12e PZ |
4263 | /* |
4264 | * Drop the rq->lock, but keep IRQ/preempt disabled. | |
4265 | */ | |
4266 | raw_spin_unlock(&this_rq->lock); | |
4267 | ||
c66eaf61 | 4268 | update_shares(this_cpu); |
dce840a0 | 4269 | rcu_read_lock(); |
1e3c88bd PZ |
4270 | for_each_domain(this_cpu, sd) { |
4271 | unsigned long interval; | |
f492e12e | 4272 | int balance = 1; |
1e3c88bd PZ |
4273 | |
4274 | if (!(sd->flags & SD_LOAD_BALANCE)) | |
4275 | continue; | |
4276 | ||
f492e12e | 4277 | if (sd->flags & SD_BALANCE_NEWIDLE) { |
1e3c88bd | 4278 | /* If we've pulled tasks over stop searching: */ |
f492e12e PZ |
4279 | pulled_task = load_balance(this_cpu, this_rq, |
4280 | sd, CPU_NEWLY_IDLE, &balance); | |
4281 | } | |
1e3c88bd PZ |
4282 | |
4283 | interval = msecs_to_jiffies(sd->balance_interval); | |
4284 | if (time_after(next_balance, sd->last_balance + interval)) | |
4285 | next_balance = sd->last_balance + interval; | |
d5ad140b NR |
4286 | if (pulled_task) { |
4287 | this_rq->idle_stamp = 0; | |
1e3c88bd | 4288 | break; |
d5ad140b | 4289 | } |
1e3c88bd | 4290 | } |
dce840a0 | 4291 | rcu_read_unlock(); |
f492e12e PZ |
4292 | |
4293 | raw_spin_lock(&this_rq->lock); | |
4294 | ||
1e3c88bd PZ |
4295 | if (pulled_task || time_after(jiffies, this_rq->next_balance)) { |
4296 | /* | |
4297 | * We are going idle. next_balance may be set based on | |
4298 | * a busy processor. So reset next_balance. | |
4299 | */ | |
4300 | this_rq->next_balance = next_balance; | |
4301 | } | |
4302 | } | |
4303 | ||
4304 | /* | |
969c7921 TH |
4305 | * active_load_balance_cpu_stop is run by cpu stopper. It pushes |
4306 | * running tasks off the busiest CPU onto idle CPUs. It requires at | |
4307 | * least 1 task to be running on each physical CPU where possible, and | |
4308 | * avoids physical / logical imbalances. | |
1e3c88bd | 4309 | */ |
969c7921 | 4310 | static int active_load_balance_cpu_stop(void *data) |
1e3c88bd | 4311 | { |
969c7921 TH |
4312 | struct rq *busiest_rq = data; |
4313 | int busiest_cpu = cpu_of(busiest_rq); | |
1e3c88bd | 4314 | int target_cpu = busiest_rq->push_cpu; |
969c7921 | 4315 | struct rq *target_rq = cpu_rq(target_cpu); |
1e3c88bd | 4316 | struct sched_domain *sd; |
969c7921 TH |
4317 | |
4318 | raw_spin_lock_irq(&busiest_rq->lock); | |
4319 | ||
4320 | /* make sure the requested cpu hasn't gone down in the meantime */ | |
4321 | if (unlikely(busiest_cpu != smp_processor_id() || | |
4322 | !busiest_rq->active_balance)) | |
4323 | goto out_unlock; | |
1e3c88bd PZ |
4324 | |
4325 | /* Is there any task to move? */ | |
4326 | if (busiest_rq->nr_running <= 1) | |
969c7921 | 4327 | goto out_unlock; |
1e3c88bd PZ |
4328 | |
4329 | /* | |
4330 | * This condition is "impossible", if it occurs | |
4331 | * we need to fix it. Originally reported by | |
4332 | * Bjorn Helgaas on a 128-cpu setup. | |
4333 | */ | |
4334 | BUG_ON(busiest_rq == target_rq); | |
4335 | ||
4336 | /* move a task from busiest_rq to target_rq */ | |
4337 | double_lock_balance(busiest_rq, target_rq); | |
1e3c88bd PZ |
4338 | |
4339 | /* Search for an sd spanning us and the target CPU. */ | |
dce840a0 | 4340 | rcu_read_lock(); |
1e3c88bd PZ |
4341 | for_each_domain(target_cpu, sd) { |
4342 | if ((sd->flags & SD_LOAD_BALANCE) && | |
4343 | cpumask_test_cpu(busiest_cpu, sched_domain_span(sd))) | |
4344 | break; | |
4345 | } | |
4346 | ||
4347 | if (likely(sd)) { | |
4348 | schedstat_inc(sd, alb_count); | |
4349 | ||
4350 | if (move_one_task(target_rq, target_cpu, busiest_rq, | |
4351 | sd, CPU_IDLE)) | |
4352 | schedstat_inc(sd, alb_pushed); | |
4353 | else | |
4354 | schedstat_inc(sd, alb_failed); | |
4355 | } | |
dce840a0 | 4356 | rcu_read_unlock(); |
1e3c88bd | 4357 | double_unlock_balance(busiest_rq, target_rq); |
969c7921 TH |
4358 | out_unlock: |
4359 | busiest_rq->active_balance = 0; | |
4360 | raw_spin_unlock_irq(&busiest_rq->lock); | |
4361 | return 0; | |
1e3c88bd PZ |
4362 | } |
4363 | ||
4364 | #ifdef CONFIG_NO_HZ | |
83cd4fe2 VP |
4365 | /* |
4366 | * idle load balancing details | |
4367 | * - One of the idle CPUs nominates itself as idle load_balancer, while | |
4368 | * entering idle. | |
4369 | * - This idle load balancer CPU will also go into tickless mode when | |
4370 | * it is idle, just like all other idle CPUs | |
4371 | * - When one of the busy CPUs notice that there may be an idle rebalancing | |
4372 | * needed, they will kick the idle load balancer, which then does idle | |
4373 | * load balancing for all the idle CPUs. | |
4374 | */ | |
1e3c88bd PZ |
4375 | static struct { |
4376 | atomic_t load_balancer; | |
83cd4fe2 VP |
4377 | atomic_t first_pick_cpu; |
4378 | atomic_t second_pick_cpu; | |
4379 | cpumask_var_t idle_cpus_mask; | |
4380 | cpumask_var_t grp_idle_mask; | |
4381 | unsigned long next_balance; /* in jiffy units */ | |
4382 | } nohz ____cacheline_aligned; | |
1e3c88bd PZ |
4383 | |
4384 | int get_nohz_load_balancer(void) | |
4385 | { | |
4386 | return atomic_read(&nohz.load_balancer); | |
4387 | } | |
4388 | ||
4389 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) | |
4390 | /** | |
4391 | * lowest_flag_domain - Return lowest sched_domain containing flag. | |
4392 | * @cpu: The cpu whose lowest level of sched domain is to | |
4393 | * be returned. | |
4394 | * @flag: The flag to check for the lowest sched_domain | |
4395 | * for the given cpu. | |
4396 | * | |
4397 | * Returns the lowest sched_domain of a cpu which contains the given flag. | |
4398 | */ | |
4399 | static inline struct sched_domain *lowest_flag_domain(int cpu, int flag) | |
4400 | { | |
4401 | struct sched_domain *sd; | |
4402 | ||
4403 | for_each_domain(cpu, sd) | |
08354716 | 4404 | if (sd->flags & flag) |
1e3c88bd PZ |
4405 | break; |
4406 | ||
4407 | return sd; | |
4408 | } | |
4409 | ||
4410 | /** | |
4411 | * for_each_flag_domain - Iterates over sched_domains containing the flag. | |
4412 | * @cpu: The cpu whose domains we're iterating over. | |
4413 | * @sd: variable holding the value of the power_savings_sd | |
4414 | * for cpu. | |
4415 | * @flag: The flag to filter the sched_domains to be iterated. | |
4416 | * | |
4417 | * Iterates over all the scheduler domains for a given cpu that has the 'flag' | |
4418 | * set, starting from the lowest sched_domain to the highest. | |
4419 | */ | |
4420 | #define for_each_flag_domain(cpu, sd, flag) \ | |
4421 | for (sd = lowest_flag_domain(cpu, flag); \ | |
4422 | (sd && (sd->flags & flag)); sd = sd->parent) | |
4423 | ||
4424 | /** | |
4425 | * is_semi_idle_group - Checks if the given sched_group is semi-idle. | |
4426 | * @ilb_group: group to be checked for semi-idleness | |
4427 | * | |
4428 | * Returns: 1 if the group is semi-idle. 0 otherwise. | |
4429 | * | |
4430 | * We define a sched_group to be semi idle if it has atleast one idle-CPU | |
4431 | * and atleast one non-idle CPU. This helper function checks if the given | |
4432 | * sched_group is semi-idle or not. | |
4433 | */ | |
4434 | static inline int is_semi_idle_group(struct sched_group *ilb_group) | |
4435 | { | |
83cd4fe2 | 4436 | cpumask_and(nohz.grp_idle_mask, nohz.idle_cpus_mask, |
1e3c88bd PZ |
4437 | sched_group_cpus(ilb_group)); |
4438 | ||
4439 | /* | |
4440 | * A sched_group is semi-idle when it has atleast one busy cpu | |
4441 | * and atleast one idle cpu. | |
4442 | */ | |
83cd4fe2 | 4443 | if (cpumask_empty(nohz.grp_idle_mask)) |
1e3c88bd PZ |
4444 | return 0; |
4445 | ||
83cd4fe2 | 4446 | if (cpumask_equal(nohz.grp_idle_mask, sched_group_cpus(ilb_group))) |
1e3c88bd PZ |
4447 | return 0; |
4448 | ||
4449 | return 1; | |
4450 | } | |
4451 | /** | |
4452 | * find_new_ilb - Finds the optimum idle load balancer for nomination. | |
4453 | * @cpu: The cpu which is nominating a new idle_load_balancer. | |
4454 | * | |
4455 | * Returns: Returns the id of the idle load balancer if it exists, | |
4456 | * Else, returns >= nr_cpu_ids. | |
4457 | * | |
4458 | * This algorithm picks the idle load balancer such that it belongs to a | |
4459 | * semi-idle powersavings sched_domain. The idea is to try and avoid | |
4460 | * completely idle packages/cores just for the purpose of idle load balancing | |
4461 | * when there are other idle cpu's which are better suited for that job. | |
4462 | */ | |
4463 | static int find_new_ilb(int cpu) | |
4464 | { | |
4465 | struct sched_domain *sd; | |
4466 | struct sched_group *ilb_group; | |
dce840a0 | 4467 | int ilb = nr_cpu_ids; |
1e3c88bd PZ |
4468 | |
4469 | /* | |
4470 | * Have idle load balancer selection from semi-idle packages only | |
4471 | * when power-aware load balancing is enabled | |
4472 | */ | |
4473 | if (!(sched_smt_power_savings || sched_mc_power_savings)) | |
4474 | goto out_done; | |
4475 | ||
4476 | /* | |
4477 | * Optimize for the case when we have no idle CPUs or only one | |
4478 | * idle CPU. Don't walk the sched_domain hierarchy in such cases | |
4479 | */ | |
83cd4fe2 | 4480 | if (cpumask_weight(nohz.idle_cpus_mask) < 2) |
1e3c88bd PZ |
4481 | goto out_done; |
4482 | ||
dce840a0 | 4483 | rcu_read_lock(); |
1e3c88bd PZ |
4484 | for_each_flag_domain(cpu, sd, SD_POWERSAVINGS_BALANCE) { |
4485 | ilb_group = sd->groups; | |
4486 | ||
4487 | do { | |
dce840a0 PZ |
4488 | if (is_semi_idle_group(ilb_group)) { |
4489 | ilb = cpumask_first(nohz.grp_idle_mask); | |
4490 | goto unlock; | |
4491 | } | |
1e3c88bd PZ |
4492 | |
4493 | ilb_group = ilb_group->next; | |
4494 | ||
4495 | } while (ilb_group != sd->groups); | |
4496 | } | |
dce840a0 PZ |
4497 | unlock: |
4498 | rcu_read_unlock(); | |
1e3c88bd PZ |
4499 | |
4500 | out_done: | |
dce840a0 | 4501 | return ilb; |
1e3c88bd PZ |
4502 | } |
4503 | #else /* (CONFIG_SCHED_MC || CONFIG_SCHED_SMT) */ | |
4504 | static inline int find_new_ilb(int call_cpu) | |
4505 | { | |
83cd4fe2 | 4506 | return nr_cpu_ids; |
1e3c88bd PZ |
4507 | } |
4508 | #endif | |
4509 | ||
83cd4fe2 VP |
4510 | /* |
4511 | * Kick a CPU to do the nohz balancing, if it is time for it. We pick the | |
4512 | * nohz_load_balancer CPU (if there is one) otherwise fallback to any idle | |
4513 | * CPU (if there is one). | |
4514 | */ | |
4515 | static void nohz_balancer_kick(int cpu) | |
4516 | { | |
4517 | int ilb_cpu; | |
4518 | ||
4519 | nohz.next_balance++; | |
4520 | ||
4521 | ilb_cpu = get_nohz_load_balancer(); | |
4522 | ||
4523 | if (ilb_cpu >= nr_cpu_ids) { | |
4524 | ilb_cpu = cpumask_first(nohz.idle_cpus_mask); | |
4525 | if (ilb_cpu >= nr_cpu_ids) | |
4526 | return; | |
4527 | } | |
4528 | ||
4529 | if (!cpu_rq(ilb_cpu)->nohz_balance_kick) { | |
83cd4fe2 | 4530 | cpu_rq(ilb_cpu)->nohz_balance_kick = 1; |
ca38062e SS |
4531 | |
4532 | smp_mb(); | |
4533 | /* | |
4534 | * Use smp_send_reschedule() instead of resched_cpu(). | |
4535 | * This way we generate a sched IPI on the target cpu which | |
4536 | * is idle. And the softirq performing nohz idle load balance | |
4537 | * will be run before returning from the IPI. | |
4538 | */ | |
4539 | smp_send_reschedule(ilb_cpu); | |
83cd4fe2 VP |
4540 | } |
4541 | return; | |
4542 | } | |
4543 | ||
1e3c88bd PZ |
4544 | /* |
4545 | * This routine will try to nominate the ilb (idle load balancing) | |
4546 | * owner among the cpus whose ticks are stopped. ilb owner will do the idle | |
83cd4fe2 | 4547 | * load balancing on behalf of all those cpus. |
1e3c88bd | 4548 | * |
83cd4fe2 VP |
4549 | * When the ilb owner becomes busy, we will not have new ilb owner until some |
4550 | * idle CPU wakes up and goes back to idle or some busy CPU tries to kick | |
4551 | * idle load balancing by kicking one of the idle CPUs. | |
1e3c88bd | 4552 | * |
83cd4fe2 VP |
4553 | * Ticks are stopped for the ilb owner as well, with busy CPU kicking this |
4554 | * ilb owner CPU in future (when there is a need for idle load balancing on | |
4555 | * behalf of all idle CPUs). | |
1e3c88bd | 4556 | */ |
83cd4fe2 | 4557 | void select_nohz_load_balancer(int stop_tick) |
1e3c88bd PZ |
4558 | { |
4559 | int cpu = smp_processor_id(); | |
4560 | ||
4561 | if (stop_tick) { | |
1e3c88bd PZ |
4562 | if (!cpu_active(cpu)) { |
4563 | if (atomic_read(&nohz.load_balancer) != cpu) | |
83cd4fe2 | 4564 | return; |
1e3c88bd PZ |
4565 | |
4566 | /* | |
4567 | * If we are going offline and still the leader, | |
4568 | * give up! | |
4569 | */ | |
83cd4fe2 VP |
4570 | if (atomic_cmpxchg(&nohz.load_balancer, cpu, |
4571 | nr_cpu_ids) != cpu) | |
1e3c88bd PZ |
4572 | BUG(); |
4573 | ||
83cd4fe2 | 4574 | return; |
1e3c88bd PZ |
4575 | } |
4576 | ||
83cd4fe2 | 4577 | cpumask_set_cpu(cpu, nohz.idle_cpus_mask); |
1e3c88bd | 4578 | |
83cd4fe2 VP |
4579 | if (atomic_read(&nohz.first_pick_cpu) == cpu) |
4580 | atomic_cmpxchg(&nohz.first_pick_cpu, cpu, nr_cpu_ids); | |
4581 | if (atomic_read(&nohz.second_pick_cpu) == cpu) | |
4582 | atomic_cmpxchg(&nohz.second_pick_cpu, cpu, nr_cpu_ids); | |
1e3c88bd | 4583 | |
83cd4fe2 | 4584 | if (atomic_read(&nohz.load_balancer) >= nr_cpu_ids) { |
1e3c88bd PZ |
4585 | int new_ilb; |
4586 | ||
83cd4fe2 VP |
4587 | /* make me the ilb owner */ |
4588 | if (atomic_cmpxchg(&nohz.load_balancer, nr_cpu_ids, | |
4589 | cpu) != nr_cpu_ids) | |
4590 | return; | |
4591 | ||
1e3c88bd PZ |
4592 | /* |
4593 | * Check to see if there is a more power-efficient | |
4594 | * ilb. | |
4595 | */ | |
4596 | new_ilb = find_new_ilb(cpu); | |
4597 | if (new_ilb < nr_cpu_ids && new_ilb != cpu) { | |
83cd4fe2 | 4598 | atomic_set(&nohz.load_balancer, nr_cpu_ids); |
1e3c88bd | 4599 | resched_cpu(new_ilb); |
83cd4fe2 | 4600 | return; |
1e3c88bd | 4601 | } |
83cd4fe2 | 4602 | return; |
1e3c88bd PZ |
4603 | } |
4604 | } else { | |
83cd4fe2 VP |
4605 | if (!cpumask_test_cpu(cpu, nohz.idle_cpus_mask)) |
4606 | return; | |
1e3c88bd | 4607 | |
83cd4fe2 | 4608 | cpumask_clear_cpu(cpu, nohz.idle_cpus_mask); |
1e3c88bd PZ |
4609 | |
4610 | if (atomic_read(&nohz.load_balancer) == cpu) | |
83cd4fe2 VP |
4611 | if (atomic_cmpxchg(&nohz.load_balancer, cpu, |
4612 | nr_cpu_ids) != cpu) | |
1e3c88bd PZ |
4613 | BUG(); |
4614 | } | |
83cd4fe2 | 4615 | return; |
1e3c88bd PZ |
4616 | } |
4617 | #endif | |
4618 | ||
4619 | static DEFINE_SPINLOCK(balancing); | |
4620 | ||
49c022e6 PZ |
4621 | static unsigned long __read_mostly max_load_balance_interval = HZ/10; |
4622 | ||
4623 | /* | |
4624 | * Scale the max load_balance interval with the number of CPUs in the system. | |
4625 | * This trades load-balance latency on larger machines for less cross talk. | |
4626 | */ | |
4627 | static void update_max_interval(void) | |
4628 | { | |
4629 | max_load_balance_interval = HZ*num_online_cpus()/10; | |
4630 | } | |
4631 | ||
1e3c88bd PZ |
4632 | /* |
4633 | * It checks each scheduling domain to see if it is due to be balanced, | |
4634 | * and initiates a balancing operation if so. | |
4635 | * | |
4636 | * Balancing parameters are set up in arch_init_sched_domains. | |
4637 | */ | |
4638 | static void rebalance_domains(int cpu, enum cpu_idle_type idle) | |
4639 | { | |
4640 | int balance = 1; | |
4641 | struct rq *rq = cpu_rq(cpu); | |
4642 | unsigned long interval; | |
4643 | struct sched_domain *sd; | |
4644 | /* Earliest time when we have to do rebalance again */ | |
4645 | unsigned long next_balance = jiffies + 60*HZ; | |
4646 | int update_next_balance = 0; | |
4647 | int need_serialize; | |
4648 | ||
2069dd75 PZ |
4649 | update_shares(cpu); |
4650 | ||
dce840a0 | 4651 | rcu_read_lock(); |
1e3c88bd PZ |
4652 | for_each_domain(cpu, sd) { |
4653 | if (!(sd->flags & SD_LOAD_BALANCE)) | |
4654 | continue; | |
4655 | ||
4656 | interval = sd->balance_interval; | |
4657 | if (idle != CPU_IDLE) | |
4658 | interval *= sd->busy_factor; | |
4659 | ||
4660 | /* scale ms to jiffies */ | |
4661 | interval = msecs_to_jiffies(interval); | |
49c022e6 | 4662 | interval = clamp(interval, 1UL, max_load_balance_interval); |
1e3c88bd PZ |
4663 | |
4664 | need_serialize = sd->flags & SD_SERIALIZE; | |
4665 | ||
4666 | if (need_serialize) { | |
4667 | if (!spin_trylock(&balancing)) | |
4668 | goto out; | |
4669 | } | |
4670 | ||
4671 | if (time_after_eq(jiffies, sd->last_balance + interval)) { | |
4672 | if (load_balance(cpu, rq, sd, idle, &balance)) { | |
4673 | /* | |
4674 | * We've pulled tasks over so either we're no | |
c186fafe | 4675 | * longer idle. |
1e3c88bd PZ |
4676 | */ |
4677 | idle = CPU_NOT_IDLE; | |
4678 | } | |
4679 | sd->last_balance = jiffies; | |
4680 | } | |
4681 | if (need_serialize) | |
4682 | spin_unlock(&balancing); | |
4683 | out: | |
4684 | if (time_after(next_balance, sd->last_balance + interval)) { | |
4685 | next_balance = sd->last_balance + interval; | |
4686 | update_next_balance = 1; | |
4687 | } | |
4688 | ||
4689 | /* | |
4690 | * Stop the load balance at this level. There is another | |
4691 | * CPU in our sched group which is doing load balancing more | |
4692 | * actively. | |
4693 | */ | |
4694 | if (!balance) | |
4695 | break; | |
4696 | } | |
dce840a0 | 4697 | rcu_read_unlock(); |
1e3c88bd PZ |
4698 | |
4699 | /* | |
4700 | * next_balance will be updated only when there is a need. | |
4701 | * When the cpu is attached to null domain for ex, it will not be | |
4702 | * updated. | |
4703 | */ | |
4704 | if (likely(update_next_balance)) | |
4705 | rq->next_balance = next_balance; | |
4706 | } | |
4707 | ||
83cd4fe2 | 4708 | #ifdef CONFIG_NO_HZ |
1e3c88bd | 4709 | /* |
83cd4fe2 | 4710 | * In CONFIG_NO_HZ case, the idle balance kickee will do the |
1e3c88bd PZ |
4711 | * rebalancing for all the cpus for whom scheduler ticks are stopped. |
4712 | */ | |
83cd4fe2 VP |
4713 | static void nohz_idle_balance(int this_cpu, enum cpu_idle_type idle) |
4714 | { | |
4715 | struct rq *this_rq = cpu_rq(this_cpu); | |
4716 | struct rq *rq; | |
4717 | int balance_cpu; | |
4718 | ||
4719 | if (idle != CPU_IDLE || !this_rq->nohz_balance_kick) | |
4720 | return; | |
4721 | ||
4722 | for_each_cpu(balance_cpu, nohz.idle_cpus_mask) { | |
4723 | if (balance_cpu == this_cpu) | |
4724 | continue; | |
4725 | ||
4726 | /* | |
4727 | * If this cpu gets work to do, stop the load balancing | |
4728 | * work being done for other cpus. Next load | |
4729 | * balancing owner will pick it up. | |
4730 | */ | |
4731 | if (need_resched()) { | |
4732 | this_rq->nohz_balance_kick = 0; | |
4733 | break; | |
4734 | } | |
4735 | ||
4736 | raw_spin_lock_irq(&this_rq->lock); | |
5343bdb8 | 4737 | update_rq_clock(this_rq); |
83cd4fe2 VP |
4738 | update_cpu_load(this_rq); |
4739 | raw_spin_unlock_irq(&this_rq->lock); | |
4740 | ||
4741 | rebalance_domains(balance_cpu, CPU_IDLE); | |
4742 | ||
4743 | rq = cpu_rq(balance_cpu); | |
4744 | if (time_after(this_rq->next_balance, rq->next_balance)) | |
4745 | this_rq->next_balance = rq->next_balance; | |
4746 | } | |
4747 | nohz.next_balance = this_rq->next_balance; | |
4748 | this_rq->nohz_balance_kick = 0; | |
4749 | } | |
4750 | ||
4751 | /* | |
4752 | * Current heuristic for kicking the idle load balancer | |
4753 | * - first_pick_cpu is the one of the busy CPUs. It will kick | |
4754 | * idle load balancer when it has more than one process active. This | |
4755 | * eliminates the need for idle load balancing altogether when we have | |
4756 | * only one running process in the system (common case). | |
4757 | * - If there are more than one busy CPU, idle load balancer may have | |
4758 | * to run for active_load_balance to happen (i.e., two busy CPUs are | |
4759 | * SMT or core siblings and can run better if they move to different | |
4760 | * physical CPUs). So, second_pick_cpu is the second of the busy CPUs | |
4761 | * which will kick idle load balancer as soon as it has any load. | |
4762 | */ | |
4763 | static inline int nohz_kick_needed(struct rq *rq, int cpu) | |
4764 | { | |
4765 | unsigned long now = jiffies; | |
4766 | int ret; | |
4767 | int first_pick_cpu, second_pick_cpu; | |
4768 | ||
4769 | if (time_before(now, nohz.next_balance)) | |
4770 | return 0; | |
4771 | ||
6eb57e0d | 4772 | if (idle_cpu(cpu)) |
83cd4fe2 VP |
4773 | return 0; |
4774 | ||
4775 | first_pick_cpu = atomic_read(&nohz.first_pick_cpu); | |
4776 | second_pick_cpu = atomic_read(&nohz.second_pick_cpu); | |
4777 | ||
4778 | if (first_pick_cpu < nr_cpu_ids && first_pick_cpu != cpu && | |
4779 | second_pick_cpu < nr_cpu_ids && second_pick_cpu != cpu) | |
4780 | return 0; | |
4781 | ||
4782 | ret = atomic_cmpxchg(&nohz.first_pick_cpu, nr_cpu_ids, cpu); | |
4783 | if (ret == nr_cpu_ids || ret == cpu) { | |
4784 | atomic_cmpxchg(&nohz.second_pick_cpu, cpu, nr_cpu_ids); | |
4785 | if (rq->nr_running > 1) | |
4786 | return 1; | |
4787 | } else { | |
4788 | ret = atomic_cmpxchg(&nohz.second_pick_cpu, nr_cpu_ids, cpu); | |
4789 | if (ret == nr_cpu_ids || ret == cpu) { | |
4790 | if (rq->nr_running) | |
4791 | return 1; | |
4792 | } | |
4793 | } | |
4794 | return 0; | |
4795 | } | |
4796 | #else | |
4797 | static void nohz_idle_balance(int this_cpu, enum cpu_idle_type idle) { } | |
4798 | #endif | |
4799 | ||
4800 | /* | |
4801 | * run_rebalance_domains is triggered when needed from the scheduler tick. | |
4802 | * Also triggered for nohz idle balancing (with nohz_balancing_kick set). | |
4803 | */ | |
1e3c88bd PZ |
4804 | static void run_rebalance_domains(struct softirq_action *h) |
4805 | { | |
4806 | int this_cpu = smp_processor_id(); | |
4807 | struct rq *this_rq = cpu_rq(this_cpu); | |
6eb57e0d | 4808 | enum cpu_idle_type idle = this_rq->idle_balance ? |
1e3c88bd PZ |
4809 | CPU_IDLE : CPU_NOT_IDLE; |
4810 | ||
4811 | rebalance_domains(this_cpu, idle); | |
4812 | ||
1e3c88bd | 4813 | /* |
83cd4fe2 | 4814 | * If this cpu has a pending nohz_balance_kick, then do the |
1e3c88bd PZ |
4815 | * balancing on behalf of the other idle cpus whose ticks are |
4816 | * stopped. | |
4817 | */ | |
83cd4fe2 | 4818 | nohz_idle_balance(this_cpu, idle); |
1e3c88bd PZ |
4819 | } |
4820 | ||
4821 | static inline int on_null_domain(int cpu) | |
4822 | { | |
90a6501f | 4823 | return !rcu_dereference_sched(cpu_rq(cpu)->sd); |
1e3c88bd PZ |
4824 | } |
4825 | ||
4826 | /* | |
4827 | * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing. | |
1e3c88bd PZ |
4828 | */ |
4829 | static inline void trigger_load_balance(struct rq *rq, int cpu) | |
4830 | { | |
1e3c88bd PZ |
4831 | /* Don't need to rebalance while attached to NULL domain */ |
4832 | if (time_after_eq(jiffies, rq->next_balance) && | |
4833 | likely(!on_null_domain(cpu))) | |
4834 | raise_softirq(SCHED_SOFTIRQ); | |
83cd4fe2 VP |
4835 | #ifdef CONFIG_NO_HZ |
4836 | else if (nohz_kick_needed(rq, cpu) && likely(!on_null_domain(cpu))) | |
4837 | nohz_balancer_kick(cpu); | |
4838 | #endif | |
1e3c88bd PZ |
4839 | } |
4840 | ||
0bcdcf28 CE |
4841 | static void rq_online_fair(struct rq *rq) |
4842 | { | |
4843 | update_sysctl(); | |
4844 | } | |
4845 | ||
4846 | static void rq_offline_fair(struct rq *rq) | |
4847 | { | |
4848 | update_sysctl(); | |
4849 | } | |
4850 | ||
1e3c88bd PZ |
4851 | #else /* CONFIG_SMP */ |
4852 | ||
4853 | /* | |
4854 | * on UP we do not need to balance between CPUs: | |
4855 | */ | |
4856 | static inline void idle_balance(int cpu, struct rq *rq) | |
4857 | { | |
4858 | } | |
4859 | ||
55e12e5e | 4860 | #endif /* CONFIG_SMP */ |
e1d1484f | 4861 | |
bf0f6f24 IM |
4862 | /* |
4863 | * scheduler tick hitting a task of our scheduling class: | |
4864 | */ | |
8f4d37ec | 4865 | static void task_tick_fair(struct rq *rq, struct task_struct *curr, int queued) |
bf0f6f24 IM |
4866 | { |
4867 | struct cfs_rq *cfs_rq; | |
4868 | struct sched_entity *se = &curr->se; | |
4869 | ||
4870 | for_each_sched_entity(se) { | |
4871 | cfs_rq = cfs_rq_of(se); | |
8f4d37ec | 4872 | entity_tick(cfs_rq, se, queued); |
bf0f6f24 IM |
4873 | } |
4874 | } | |
4875 | ||
4876 | /* | |
cd29fe6f PZ |
4877 | * called on fork with the child task as argument from the parent's context |
4878 | * - child not yet on the tasklist | |
4879 | * - preemption disabled | |
bf0f6f24 | 4880 | */ |
cd29fe6f | 4881 | static void task_fork_fair(struct task_struct *p) |
bf0f6f24 | 4882 | { |
cd29fe6f | 4883 | struct cfs_rq *cfs_rq = task_cfs_rq(current); |
429d43bc | 4884 | struct sched_entity *se = &p->se, *curr = cfs_rq->curr; |
00bf7bfc | 4885 | int this_cpu = smp_processor_id(); |
cd29fe6f PZ |
4886 | struct rq *rq = this_rq(); |
4887 | unsigned long flags; | |
4888 | ||
05fa785c | 4889 | raw_spin_lock_irqsave(&rq->lock, flags); |
bf0f6f24 | 4890 | |
861d034e PZ |
4891 | update_rq_clock(rq); |
4892 | ||
b0a0f667 PM |
4893 | if (unlikely(task_cpu(p) != this_cpu)) { |
4894 | rcu_read_lock(); | |
cd29fe6f | 4895 | __set_task_cpu(p, this_cpu); |
b0a0f667 PM |
4896 | rcu_read_unlock(); |
4897 | } | |
bf0f6f24 | 4898 | |
7109c442 | 4899 | update_curr(cfs_rq); |
cd29fe6f | 4900 | |
b5d9d734 MG |
4901 | if (curr) |
4902 | se->vruntime = curr->vruntime; | |
aeb73b04 | 4903 | place_entity(cfs_rq, se, 1); |
4d78e7b6 | 4904 | |
cd29fe6f | 4905 | if (sysctl_sched_child_runs_first && curr && entity_before(curr, se)) { |
87fefa38 | 4906 | /* |
edcb60a3 IM |
4907 | * Upon rescheduling, sched_class::put_prev_task() will place |
4908 | * 'current' within the tree based on its new key value. | |
4909 | */ | |
4d78e7b6 | 4910 | swap(curr->vruntime, se->vruntime); |
aec0a514 | 4911 | resched_task(rq->curr); |
4d78e7b6 | 4912 | } |
bf0f6f24 | 4913 | |
88ec22d3 PZ |
4914 | se->vruntime -= cfs_rq->min_vruntime; |
4915 | ||
05fa785c | 4916 | raw_spin_unlock_irqrestore(&rq->lock, flags); |
bf0f6f24 IM |
4917 | } |
4918 | ||
cb469845 SR |
4919 | /* |
4920 | * Priority of the task has changed. Check to see if we preempt | |
4921 | * the current task. | |
4922 | */ | |
da7a735e PZ |
4923 | static void |
4924 | prio_changed_fair(struct rq *rq, struct task_struct *p, int oldprio) | |
cb469845 | 4925 | { |
da7a735e PZ |
4926 | if (!p->se.on_rq) |
4927 | return; | |
4928 | ||
cb469845 SR |
4929 | /* |
4930 | * Reschedule if we are currently running on this runqueue and | |
4931 | * our priority decreased, or if we are not currently running on | |
4932 | * this runqueue and our priority is higher than the current's | |
4933 | */ | |
da7a735e | 4934 | if (rq->curr == p) { |
cb469845 SR |
4935 | if (p->prio > oldprio) |
4936 | resched_task(rq->curr); | |
4937 | } else | |
15afe09b | 4938 | check_preempt_curr(rq, p, 0); |
cb469845 SR |
4939 | } |
4940 | ||
da7a735e PZ |
4941 | static void switched_from_fair(struct rq *rq, struct task_struct *p) |
4942 | { | |
4943 | struct sched_entity *se = &p->se; | |
4944 | struct cfs_rq *cfs_rq = cfs_rq_of(se); | |
4945 | ||
4946 | /* | |
4947 | * Ensure the task's vruntime is normalized, so that when its | |
4948 | * switched back to the fair class the enqueue_entity(.flags=0) will | |
4949 | * do the right thing. | |
4950 | * | |
4951 | * If it was on_rq, then the dequeue_entity(.flags=0) will already | |
4952 | * have normalized the vruntime, if it was !on_rq, then only when | |
4953 | * the task is sleeping will it still have non-normalized vruntime. | |
4954 | */ | |
4955 | if (!se->on_rq && p->state != TASK_RUNNING) { | |
4956 | /* | |
4957 | * Fix up our vruntime so that the current sleep doesn't | |
4958 | * cause 'unlimited' sleep bonus. | |
4959 | */ | |
4960 | place_entity(cfs_rq, se, 0); | |
4961 | se->vruntime -= cfs_rq->min_vruntime; | |
4962 | } | |
4963 | } | |
4964 | ||
cb469845 SR |
4965 | /* |
4966 | * We switched to the sched_fair class. | |
4967 | */ | |
da7a735e | 4968 | static void switched_to_fair(struct rq *rq, struct task_struct *p) |
cb469845 | 4969 | { |
da7a735e PZ |
4970 | if (!p->se.on_rq) |
4971 | return; | |
4972 | ||
cb469845 SR |
4973 | /* |
4974 | * We were most likely switched from sched_rt, so | |
4975 | * kick off the schedule if running, otherwise just see | |
4976 | * if we can still preempt the current task. | |
4977 | */ | |
da7a735e | 4978 | if (rq->curr == p) |
cb469845 SR |
4979 | resched_task(rq->curr); |
4980 | else | |
15afe09b | 4981 | check_preempt_curr(rq, p, 0); |
cb469845 SR |
4982 | } |
4983 | ||
83b699ed SV |
4984 | /* Account for a task changing its policy or group. |
4985 | * | |
4986 | * This routine is mostly called to set cfs_rq->curr field when a task | |
4987 | * migrates between groups/classes. | |
4988 | */ | |
4989 | static void set_curr_task_fair(struct rq *rq) | |
4990 | { | |
4991 | struct sched_entity *se = &rq->curr->se; | |
4992 | ||
ec12cb7f PT |
4993 | for_each_sched_entity(se) { |
4994 | struct cfs_rq *cfs_rq = cfs_rq_of(se); | |
4995 | ||
4996 | set_next_entity(cfs_rq, se); | |
4997 | /* ensure bandwidth has been allocated on our new cfs_rq */ | |
4998 | account_cfs_rq_runtime(cfs_rq, 0); | |
4999 | } | |
83b699ed SV |
5000 | } |
5001 | ||
810b3817 | 5002 | #ifdef CONFIG_FAIR_GROUP_SCHED |
b2b5ce02 | 5003 | static void task_move_group_fair(struct task_struct *p, int on_rq) |
810b3817 | 5004 | { |
b2b5ce02 PZ |
5005 | /* |
5006 | * If the task was not on the rq at the time of this cgroup movement | |
5007 | * it must have been asleep, sleeping tasks keep their ->vruntime | |
5008 | * absolute on their old rq until wakeup (needed for the fair sleeper | |
5009 | * bonus in place_entity()). | |
5010 | * | |
5011 | * If it was on the rq, we've just 'preempted' it, which does convert | |
5012 | * ->vruntime to a relative base. | |
5013 | * | |
5014 | * Make sure both cases convert their relative position when migrating | |
5015 | * to another cgroup's rq. This does somewhat interfere with the | |
5016 | * fair sleeper stuff for the first placement, but who cares. | |
5017 | */ | |
5018 | if (!on_rq) | |
5019 | p->se.vruntime -= cfs_rq_of(&p->se)->min_vruntime; | |
5020 | set_task_rq(p, task_cpu(p)); | |
88ec22d3 | 5021 | if (!on_rq) |
b2b5ce02 | 5022 | p->se.vruntime += cfs_rq_of(&p->se)->min_vruntime; |
810b3817 PZ |
5023 | } |
5024 | #endif | |
5025 | ||
6d686f45 | 5026 | static unsigned int get_rr_interval_fair(struct rq *rq, struct task_struct *task) |
0d721cea PW |
5027 | { |
5028 | struct sched_entity *se = &task->se; | |
0d721cea PW |
5029 | unsigned int rr_interval = 0; |
5030 | ||
5031 | /* | |
5032 | * Time slice is 0 for SCHED_OTHER tasks that are on an otherwise | |
5033 | * idle runqueue: | |
5034 | */ | |
0d721cea PW |
5035 | if (rq->cfs.load.weight) |
5036 | rr_interval = NS_TO_JIFFIES(sched_slice(&rq->cfs, se)); | |
0d721cea PW |
5037 | |
5038 | return rr_interval; | |
5039 | } | |
5040 | ||
bf0f6f24 IM |
5041 | /* |
5042 | * All the scheduling class methods: | |
5043 | */ | |
5522d5d5 IM |
5044 | static const struct sched_class fair_sched_class = { |
5045 | .next = &idle_sched_class, | |
bf0f6f24 IM |
5046 | .enqueue_task = enqueue_task_fair, |
5047 | .dequeue_task = dequeue_task_fair, | |
5048 | .yield_task = yield_task_fair, | |
d95f4122 | 5049 | .yield_to_task = yield_to_task_fair, |
bf0f6f24 | 5050 | |
2e09bf55 | 5051 | .check_preempt_curr = check_preempt_wakeup, |
bf0f6f24 IM |
5052 | |
5053 | .pick_next_task = pick_next_task_fair, | |
5054 | .put_prev_task = put_prev_task_fair, | |
5055 | ||
681f3e68 | 5056 | #ifdef CONFIG_SMP |
4ce72a2c LZ |
5057 | .select_task_rq = select_task_rq_fair, |
5058 | ||
0bcdcf28 CE |
5059 | .rq_online = rq_online_fair, |
5060 | .rq_offline = rq_offline_fair, | |
88ec22d3 PZ |
5061 | |
5062 | .task_waking = task_waking_fair, | |
681f3e68 | 5063 | #endif |
bf0f6f24 | 5064 | |
83b699ed | 5065 | .set_curr_task = set_curr_task_fair, |
bf0f6f24 | 5066 | .task_tick = task_tick_fair, |
cd29fe6f | 5067 | .task_fork = task_fork_fair, |
cb469845 SR |
5068 | |
5069 | .prio_changed = prio_changed_fair, | |
da7a735e | 5070 | .switched_from = switched_from_fair, |
cb469845 | 5071 | .switched_to = switched_to_fair, |
810b3817 | 5072 | |
0d721cea PW |
5073 | .get_rr_interval = get_rr_interval_fair, |
5074 | ||
810b3817 | 5075 | #ifdef CONFIG_FAIR_GROUP_SCHED |
b2b5ce02 | 5076 | .task_move_group = task_move_group_fair, |
810b3817 | 5077 | #endif |
bf0f6f24 IM |
5078 | }; |
5079 | ||
5080 | #ifdef CONFIG_SCHED_DEBUG | |
5cef9eca | 5081 | static void print_cfs_stats(struct seq_file *m, int cpu) |
bf0f6f24 | 5082 | { |
bf0f6f24 IM |
5083 | struct cfs_rq *cfs_rq; |
5084 | ||
5973e5b9 | 5085 | rcu_read_lock(); |
c3b64f1e | 5086 | for_each_leaf_cfs_rq(cpu_rq(cpu), cfs_rq) |
5cef9eca | 5087 | print_cfs_rq(m, cpu, cfs_rq); |
5973e5b9 | 5088 | rcu_read_unlock(); |
bf0f6f24 IM |
5089 | } |
5090 | #endif |