Commit | Line | Data |
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bf0f6f24 IM |
1 | /* |
2 | * Completely Fair Scheduling (CFS) Class (SCHED_NORMAL/SCHED_BATCH) | |
3 | * | |
4 | * Copyright (C) 2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> | |
5 | * | |
6 | * Interactivity improvements by Mike Galbraith | |
7 | * (C) 2007 Mike Galbraith <efault@gmx.de> | |
8 | * | |
9 | * Various enhancements by Dmitry Adamushko. | |
10 | * (C) 2007 Dmitry Adamushko <dmitry.adamushko@gmail.com> | |
11 | * | |
12 | * Group scheduling enhancements by Srivatsa Vaddagiri | |
13 | * Copyright IBM Corporation, 2007 | |
14 | * Author: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> | |
15 | * | |
16 | * Scaled math optimizations by Thomas Gleixner | |
17 | * Copyright (C) 2007, Thomas Gleixner <tglx@linutronix.de> | |
21805085 PZ |
18 | * |
19 | * Adaptive scheduling granularity, math enhancements by Peter Zijlstra | |
20 | * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com> | |
bf0f6f24 IM |
21 | */ |
22 | ||
9745512c | 23 | #include <linux/latencytop.h> |
1983a922 | 24 | #include <linux/sched.h> |
3436ae12 | 25 | #include <linux/cpumask.h> |
029632fb PZ |
26 | #include <linux/slab.h> |
27 | #include <linux/profile.h> | |
28 | #include <linux/interrupt.h> | |
29 | ||
30 | #include <trace/events/sched.h> | |
31 | ||
32 | #include "sched.h" | |
9745512c | 33 | |
bf0f6f24 | 34 | /* |
21805085 | 35 | * Targeted preemption latency for CPU-bound tasks: |
864616ee | 36 | * (default: 6ms * (1 + ilog(ncpus)), units: nanoseconds) |
bf0f6f24 | 37 | * |
21805085 | 38 | * NOTE: this latency value is not the same as the concept of |
d274a4ce IM |
39 | * 'timeslice length' - timeslices in CFS are of variable length |
40 | * and have no persistent notion like in traditional, time-slice | |
41 | * based scheduling concepts. | |
bf0f6f24 | 42 | * |
d274a4ce IM |
43 | * (to see the precise effective timeslice length of your workload, |
44 | * run vmstat and monitor the context-switches (cs) field) | |
bf0f6f24 | 45 | */ |
21406928 MG |
46 | unsigned int sysctl_sched_latency = 6000000ULL; |
47 | unsigned int normalized_sysctl_sched_latency = 6000000ULL; | |
2bd8e6d4 | 48 | |
1983a922 CE |
49 | /* |
50 | * The initial- and re-scaling of tunables is configurable | |
51 | * (default SCHED_TUNABLESCALING_LOG = *(1+ilog(ncpus)) | |
52 | * | |
53 | * Options are: | |
54 | * SCHED_TUNABLESCALING_NONE - unscaled, always *1 | |
55 | * SCHED_TUNABLESCALING_LOG - scaled logarithmical, *1+ilog(ncpus) | |
56 | * SCHED_TUNABLESCALING_LINEAR - scaled linear, *ncpus | |
57 | */ | |
58 | enum sched_tunable_scaling sysctl_sched_tunable_scaling | |
59 | = SCHED_TUNABLESCALING_LOG; | |
60 | ||
2bd8e6d4 | 61 | /* |
b2be5e96 | 62 | * Minimal preemption granularity for CPU-bound tasks: |
864616ee | 63 | * (default: 0.75 msec * (1 + ilog(ncpus)), units: nanoseconds) |
2bd8e6d4 | 64 | */ |
0bf377bb IM |
65 | unsigned int sysctl_sched_min_granularity = 750000ULL; |
66 | unsigned int normalized_sysctl_sched_min_granularity = 750000ULL; | |
21805085 PZ |
67 | |
68 | /* | |
b2be5e96 PZ |
69 | * is kept at sysctl_sched_latency / sysctl_sched_min_granularity |
70 | */ | |
0bf377bb | 71 | static unsigned int sched_nr_latency = 8; |
b2be5e96 PZ |
72 | |
73 | /* | |
2bba22c5 | 74 | * After fork, child runs first. If set to 0 (default) then |
b2be5e96 | 75 | * parent will (try to) run first. |
21805085 | 76 | */ |
2bba22c5 | 77 | unsigned int sysctl_sched_child_runs_first __read_mostly; |
bf0f6f24 | 78 | |
bf0f6f24 IM |
79 | /* |
80 | * SCHED_OTHER wake-up granularity. | |
172e082a | 81 | * (default: 1 msec * (1 + ilog(ncpus)), units: nanoseconds) |
bf0f6f24 IM |
82 | * |
83 | * This option delays the preemption effects of decoupled workloads | |
84 | * and reduces their over-scheduling. Synchronous workloads will still | |
85 | * have immediate wakeup/sleep latencies. | |
86 | */ | |
172e082a | 87 | unsigned int sysctl_sched_wakeup_granularity = 1000000UL; |
0bcdcf28 | 88 | unsigned int normalized_sysctl_sched_wakeup_granularity = 1000000UL; |
bf0f6f24 | 89 | |
da84d961 IM |
90 | const_debug unsigned int sysctl_sched_migration_cost = 500000UL; |
91 | ||
a7a4f8a7 PT |
92 | /* |
93 | * The exponential sliding window over which load is averaged for shares | |
94 | * distribution. | |
95 | * (default: 10msec) | |
96 | */ | |
97 | unsigned int __read_mostly sysctl_sched_shares_window = 10000000UL; | |
98 | ||
ec12cb7f PT |
99 | #ifdef CONFIG_CFS_BANDWIDTH |
100 | /* | |
101 | * Amount of runtime to allocate from global (tg) to local (per-cfs_rq) pool | |
102 | * each time a cfs_rq requests quota. | |
103 | * | |
104 | * Note: in the case that the slice exceeds the runtime remaining (either due | |
105 | * to consumption or the quota being specified to be smaller than the slice) | |
106 | * we will always only issue the remaining available time. | |
107 | * | |
108 | * default: 5 msec, units: microseconds | |
109 | */ | |
110 | unsigned int sysctl_sched_cfs_bandwidth_slice = 5000UL; | |
111 | #endif | |
112 | ||
029632fb PZ |
113 | /* |
114 | * Increase the granularity value when there are more CPUs, | |
115 | * because with more CPUs the 'effective latency' as visible | |
116 | * to users decreases. But the relationship is not linear, | |
117 | * so pick a second-best guess by going with the log2 of the | |
118 | * number of CPUs. | |
119 | * | |
120 | * This idea comes from the SD scheduler of Con Kolivas: | |
121 | */ | |
122 | static int get_update_sysctl_factor(void) | |
123 | { | |
124 | unsigned int cpus = min_t(int, num_online_cpus(), 8); | |
125 | unsigned int factor; | |
126 | ||
127 | switch (sysctl_sched_tunable_scaling) { | |
128 | case SCHED_TUNABLESCALING_NONE: | |
129 | factor = 1; | |
130 | break; | |
131 | case SCHED_TUNABLESCALING_LINEAR: | |
132 | factor = cpus; | |
133 | break; | |
134 | case SCHED_TUNABLESCALING_LOG: | |
135 | default: | |
136 | factor = 1 + ilog2(cpus); | |
137 | break; | |
138 | } | |
139 | ||
140 | return factor; | |
141 | } | |
142 | ||
143 | static void update_sysctl(void) | |
144 | { | |
145 | unsigned int factor = get_update_sysctl_factor(); | |
146 | ||
147 | #define SET_SYSCTL(name) \ | |
148 | (sysctl_##name = (factor) * normalized_sysctl_##name) | |
149 | SET_SYSCTL(sched_min_granularity); | |
150 | SET_SYSCTL(sched_latency); | |
151 | SET_SYSCTL(sched_wakeup_granularity); | |
152 | #undef SET_SYSCTL | |
153 | } | |
154 | ||
155 | void sched_init_granularity(void) | |
156 | { | |
157 | update_sysctl(); | |
158 | } | |
159 | ||
160 | #if BITS_PER_LONG == 32 | |
161 | # define WMULT_CONST (~0UL) | |
162 | #else | |
163 | # define WMULT_CONST (1UL << 32) | |
164 | #endif | |
165 | ||
166 | #define WMULT_SHIFT 32 | |
167 | ||
168 | /* | |
169 | * Shift right and round: | |
170 | */ | |
171 | #define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y)) | |
172 | ||
173 | /* | |
174 | * delta *= weight / lw | |
175 | */ | |
176 | static unsigned long | |
177 | calc_delta_mine(unsigned long delta_exec, unsigned long weight, | |
178 | struct load_weight *lw) | |
179 | { | |
180 | u64 tmp; | |
181 | ||
182 | /* | |
183 | * weight can be less than 2^SCHED_LOAD_RESOLUTION for task group sched | |
184 | * entities since MIN_SHARES = 2. Treat weight as 1 if less than | |
185 | * 2^SCHED_LOAD_RESOLUTION. | |
186 | */ | |
187 | if (likely(weight > (1UL << SCHED_LOAD_RESOLUTION))) | |
188 | tmp = (u64)delta_exec * scale_load_down(weight); | |
189 | else | |
190 | tmp = (u64)delta_exec; | |
191 | ||
192 | if (!lw->inv_weight) { | |
193 | unsigned long w = scale_load_down(lw->weight); | |
194 | ||
195 | if (BITS_PER_LONG > 32 && unlikely(w >= WMULT_CONST)) | |
196 | lw->inv_weight = 1; | |
197 | else if (unlikely(!w)) | |
198 | lw->inv_weight = WMULT_CONST; | |
199 | else | |
200 | lw->inv_weight = WMULT_CONST / w; | |
201 | } | |
202 | ||
203 | /* | |
204 | * Check whether we'd overflow the 64-bit multiplication: | |
205 | */ | |
206 | if (unlikely(tmp > WMULT_CONST)) | |
207 | tmp = SRR(SRR(tmp, WMULT_SHIFT/2) * lw->inv_weight, | |
208 | WMULT_SHIFT/2); | |
209 | else | |
210 | tmp = SRR(tmp * lw->inv_weight, WMULT_SHIFT); | |
211 | ||
212 | return (unsigned long)min(tmp, (u64)(unsigned long)LONG_MAX); | |
213 | } | |
214 | ||
215 | ||
216 | const struct sched_class fair_sched_class; | |
a4c2f00f | 217 | |
bf0f6f24 IM |
218 | /************************************************************** |
219 | * CFS operations on generic schedulable entities: | |
220 | */ | |
221 | ||
62160e3f | 222 | #ifdef CONFIG_FAIR_GROUP_SCHED |
bf0f6f24 | 223 | |
62160e3f | 224 | /* cpu runqueue to which this cfs_rq is attached */ |
bf0f6f24 IM |
225 | static inline struct rq *rq_of(struct cfs_rq *cfs_rq) |
226 | { | |
62160e3f | 227 | return cfs_rq->rq; |
bf0f6f24 IM |
228 | } |
229 | ||
62160e3f IM |
230 | /* An entity is a task if it doesn't "own" a runqueue */ |
231 | #define entity_is_task(se) (!se->my_q) | |
bf0f6f24 | 232 | |
8f48894f PZ |
233 | static inline struct task_struct *task_of(struct sched_entity *se) |
234 | { | |
235 | #ifdef CONFIG_SCHED_DEBUG | |
236 | WARN_ON_ONCE(!entity_is_task(se)); | |
237 | #endif | |
238 | return container_of(se, struct task_struct, se); | |
239 | } | |
240 | ||
b758149c PZ |
241 | /* Walk up scheduling entities hierarchy */ |
242 | #define for_each_sched_entity(se) \ | |
243 | for (; se; se = se->parent) | |
244 | ||
245 | static inline struct cfs_rq *task_cfs_rq(struct task_struct *p) | |
246 | { | |
247 | return p->se.cfs_rq; | |
248 | } | |
249 | ||
250 | /* runqueue on which this entity is (to be) queued */ | |
251 | static inline struct cfs_rq *cfs_rq_of(struct sched_entity *se) | |
252 | { | |
253 | return se->cfs_rq; | |
254 | } | |
255 | ||
256 | /* runqueue "owned" by this group */ | |
257 | static inline struct cfs_rq *group_cfs_rq(struct sched_entity *grp) | |
258 | { | |
259 | return grp->my_q; | |
260 | } | |
261 | ||
3d4b47b4 PZ |
262 | static inline void list_add_leaf_cfs_rq(struct cfs_rq *cfs_rq) |
263 | { | |
264 | if (!cfs_rq->on_list) { | |
67e86250 PT |
265 | /* |
266 | * Ensure we either appear before our parent (if already | |
267 | * enqueued) or force our parent to appear after us when it is | |
268 | * enqueued. The fact that we always enqueue bottom-up | |
269 | * reduces this to two cases. | |
270 | */ | |
271 | if (cfs_rq->tg->parent && | |
272 | cfs_rq->tg->parent->cfs_rq[cpu_of(rq_of(cfs_rq))]->on_list) { | |
273 | list_add_rcu(&cfs_rq->leaf_cfs_rq_list, | |
274 | &rq_of(cfs_rq)->leaf_cfs_rq_list); | |
275 | } else { | |
276 | list_add_tail_rcu(&cfs_rq->leaf_cfs_rq_list, | |
3d4b47b4 | 277 | &rq_of(cfs_rq)->leaf_cfs_rq_list); |
67e86250 | 278 | } |
3d4b47b4 PZ |
279 | |
280 | cfs_rq->on_list = 1; | |
281 | } | |
282 | } | |
283 | ||
284 | static inline void list_del_leaf_cfs_rq(struct cfs_rq *cfs_rq) | |
285 | { | |
286 | if (cfs_rq->on_list) { | |
287 | list_del_rcu(&cfs_rq->leaf_cfs_rq_list); | |
288 | cfs_rq->on_list = 0; | |
289 | } | |
290 | } | |
291 | ||
b758149c PZ |
292 | /* Iterate thr' all leaf cfs_rq's on a runqueue */ |
293 | #define for_each_leaf_cfs_rq(rq, cfs_rq) \ | |
294 | list_for_each_entry_rcu(cfs_rq, &rq->leaf_cfs_rq_list, leaf_cfs_rq_list) | |
295 | ||
296 | /* Do the two (enqueued) entities belong to the same group ? */ | |
297 | static inline int | |
298 | is_same_group(struct sched_entity *se, struct sched_entity *pse) | |
299 | { | |
300 | if (se->cfs_rq == pse->cfs_rq) | |
301 | return 1; | |
302 | ||
303 | return 0; | |
304 | } | |
305 | ||
306 | static inline struct sched_entity *parent_entity(struct sched_entity *se) | |
307 | { | |
308 | return se->parent; | |
309 | } | |
310 | ||
464b7527 PZ |
311 | /* return depth at which a sched entity is present in the hierarchy */ |
312 | static inline int depth_se(struct sched_entity *se) | |
313 | { | |
314 | int depth = 0; | |
315 | ||
316 | for_each_sched_entity(se) | |
317 | depth++; | |
318 | ||
319 | return depth; | |
320 | } | |
321 | ||
322 | static void | |
323 | find_matching_se(struct sched_entity **se, struct sched_entity **pse) | |
324 | { | |
325 | int se_depth, pse_depth; | |
326 | ||
327 | /* | |
328 | * preemption test can be made between sibling entities who are in the | |
329 | * same cfs_rq i.e who have a common parent. Walk up the hierarchy of | |
330 | * both tasks until we find their ancestors who are siblings of common | |
331 | * parent. | |
332 | */ | |
333 | ||
334 | /* First walk up until both entities are at same depth */ | |
335 | se_depth = depth_se(*se); | |
336 | pse_depth = depth_se(*pse); | |
337 | ||
338 | while (se_depth > pse_depth) { | |
339 | se_depth--; | |
340 | *se = parent_entity(*se); | |
341 | } | |
342 | ||
343 | while (pse_depth > se_depth) { | |
344 | pse_depth--; | |
345 | *pse = parent_entity(*pse); | |
346 | } | |
347 | ||
348 | while (!is_same_group(*se, *pse)) { | |
349 | *se = parent_entity(*se); | |
350 | *pse = parent_entity(*pse); | |
351 | } | |
352 | } | |
353 | ||
8f48894f PZ |
354 | #else /* !CONFIG_FAIR_GROUP_SCHED */ |
355 | ||
356 | static inline struct task_struct *task_of(struct sched_entity *se) | |
357 | { | |
358 | return container_of(se, struct task_struct, se); | |
359 | } | |
bf0f6f24 | 360 | |
62160e3f IM |
361 | static inline struct rq *rq_of(struct cfs_rq *cfs_rq) |
362 | { | |
363 | return container_of(cfs_rq, struct rq, cfs); | |
bf0f6f24 IM |
364 | } |
365 | ||
366 | #define entity_is_task(se) 1 | |
367 | ||
b758149c PZ |
368 | #define for_each_sched_entity(se) \ |
369 | for (; se; se = NULL) | |
bf0f6f24 | 370 | |
b758149c | 371 | static inline struct cfs_rq *task_cfs_rq(struct task_struct *p) |
bf0f6f24 | 372 | { |
b758149c | 373 | return &task_rq(p)->cfs; |
bf0f6f24 IM |
374 | } |
375 | ||
b758149c PZ |
376 | static inline struct cfs_rq *cfs_rq_of(struct sched_entity *se) |
377 | { | |
378 | struct task_struct *p = task_of(se); | |
379 | struct rq *rq = task_rq(p); | |
380 | ||
381 | return &rq->cfs; | |
382 | } | |
383 | ||
384 | /* runqueue "owned" by this group */ | |
385 | static inline struct cfs_rq *group_cfs_rq(struct sched_entity *grp) | |
386 | { | |
387 | return NULL; | |
388 | } | |
389 | ||
3d4b47b4 PZ |
390 | static inline void list_add_leaf_cfs_rq(struct cfs_rq *cfs_rq) |
391 | { | |
392 | } | |
393 | ||
394 | static inline void list_del_leaf_cfs_rq(struct cfs_rq *cfs_rq) | |
395 | { | |
396 | } | |
397 | ||
b758149c PZ |
398 | #define for_each_leaf_cfs_rq(rq, cfs_rq) \ |
399 | for (cfs_rq = &rq->cfs; cfs_rq; cfs_rq = NULL) | |
400 | ||
401 | static inline int | |
402 | is_same_group(struct sched_entity *se, struct sched_entity *pse) | |
403 | { | |
404 | return 1; | |
405 | } | |
406 | ||
407 | static inline struct sched_entity *parent_entity(struct sched_entity *se) | |
408 | { | |
409 | return NULL; | |
410 | } | |
411 | ||
464b7527 PZ |
412 | static inline void |
413 | find_matching_se(struct sched_entity **se, struct sched_entity **pse) | |
414 | { | |
415 | } | |
416 | ||
b758149c PZ |
417 | #endif /* CONFIG_FAIR_GROUP_SCHED */ |
418 | ||
ec12cb7f PT |
419 | static void account_cfs_rq_runtime(struct cfs_rq *cfs_rq, |
420 | unsigned long delta_exec); | |
bf0f6f24 IM |
421 | |
422 | /************************************************************** | |
423 | * Scheduling class tree data structure manipulation methods: | |
424 | */ | |
425 | ||
0702e3eb | 426 | static inline u64 max_vruntime(u64 min_vruntime, u64 vruntime) |
02e0431a | 427 | { |
368059a9 PZ |
428 | s64 delta = (s64)(vruntime - min_vruntime); |
429 | if (delta > 0) | |
02e0431a PZ |
430 | min_vruntime = vruntime; |
431 | ||
432 | return min_vruntime; | |
433 | } | |
434 | ||
0702e3eb | 435 | static inline u64 min_vruntime(u64 min_vruntime, u64 vruntime) |
b0ffd246 PZ |
436 | { |
437 | s64 delta = (s64)(vruntime - min_vruntime); | |
438 | if (delta < 0) | |
439 | min_vruntime = vruntime; | |
440 | ||
441 | return min_vruntime; | |
442 | } | |
443 | ||
54fdc581 FC |
444 | static inline int entity_before(struct sched_entity *a, |
445 | struct sched_entity *b) | |
446 | { | |
447 | return (s64)(a->vruntime - b->vruntime) < 0; | |
448 | } | |
449 | ||
1af5f730 PZ |
450 | static void update_min_vruntime(struct cfs_rq *cfs_rq) |
451 | { | |
452 | u64 vruntime = cfs_rq->min_vruntime; | |
453 | ||
454 | if (cfs_rq->curr) | |
455 | vruntime = cfs_rq->curr->vruntime; | |
456 | ||
457 | if (cfs_rq->rb_leftmost) { | |
458 | struct sched_entity *se = rb_entry(cfs_rq->rb_leftmost, | |
459 | struct sched_entity, | |
460 | run_node); | |
461 | ||
e17036da | 462 | if (!cfs_rq->curr) |
1af5f730 PZ |
463 | vruntime = se->vruntime; |
464 | else | |
465 | vruntime = min_vruntime(vruntime, se->vruntime); | |
466 | } | |
467 | ||
468 | cfs_rq->min_vruntime = max_vruntime(cfs_rq->min_vruntime, vruntime); | |
3fe1698b PZ |
469 | #ifndef CONFIG_64BIT |
470 | smp_wmb(); | |
471 | cfs_rq->min_vruntime_copy = cfs_rq->min_vruntime; | |
472 | #endif | |
1af5f730 PZ |
473 | } |
474 | ||
bf0f6f24 IM |
475 | /* |
476 | * Enqueue an entity into the rb-tree: | |
477 | */ | |
0702e3eb | 478 | static void __enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 IM |
479 | { |
480 | struct rb_node **link = &cfs_rq->tasks_timeline.rb_node; | |
481 | struct rb_node *parent = NULL; | |
482 | struct sched_entity *entry; | |
bf0f6f24 IM |
483 | int leftmost = 1; |
484 | ||
485 | /* | |
486 | * Find the right place in the rbtree: | |
487 | */ | |
488 | while (*link) { | |
489 | parent = *link; | |
490 | entry = rb_entry(parent, struct sched_entity, run_node); | |
491 | /* | |
492 | * We dont care about collisions. Nodes with | |
493 | * the same key stay together. | |
494 | */ | |
2bd2d6f2 | 495 | if (entity_before(se, entry)) { |
bf0f6f24 IM |
496 | link = &parent->rb_left; |
497 | } else { | |
498 | link = &parent->rb_right; | |
499 | leftmost = 0; | |
500 | } | |
501 | } | |
502 | ||
503 | /* | |
504 | * Maintain a cache of leftmost tree entries (it is frequently | |
505 | * used): | |
506 | */ | |
1af5f730 | 507 | if (leftmost) |
57cb499d | 508 | cfs_rq->rb_leftmost = &se->run_node; |
bf0f6f24 IM |
509 | |
510 | rb_link_node(&se->run_node, parent, link); | |
511 | rb_insert_color(&se->run_node, &cfs_rq->tasks_timeline); | |
bf0f6f24 IM |
512 | } |
513 | ||
0702e3eb | 514 | static void __dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 515 | { |
3fe69747 PZ |
516 | if (cfs_rq->rb_leftmost == &se->run_node) { |
517 | struct rb_node *next_node; | |
3fe69747 PZ |
518 | |
519 | next_node = rb_next(&se->run_node); | |
520 | cfs_rq->rb_leftmost = next_node; | |
3fe69747 | 521 | } |
e9acbff6 | 522 | |
bf0f6f24 | 523 | rb_erase(&se->run_node, &cfs_rq->tasks_timeline); |
bf0f6f24 IM |
524 | } |
525 | ||
029632fb | 526 | struct sched_entity *__pick_first_entity(struct cfs_rq *cfs_rq) |
bf0f6f24 | 527 | { |
f4b6755f PZ |
528 | struct rb_node *left = cfs_rq->rb_leftmost; |
529 | ||
530 | if (!left) | |
531 | return NULL; | |
532 | ||
533 | return rb_entry(left, struct sched_entity, run_node); | |
bf0f6f24 IM |
534 | } |
535 | ||
ac53db59 RR |
536 | static struct sched_entity *__pick_next_entity(struct sched_entity *se) |
537 | { | |
538 | struct rb_node *next = rb_next(&se->run_node); | |
539 | ||
540 | if (!next) | |
541 | return NULL; | |
542 | ||
543 | return rb_entry(next, struct sched_entity, run_node); | |
544 | } | |
545 | ||
546 | #ifdef CONFIG_SCHED_DEBUG | |
029632fb | 547 | struct sched_entity *__pick_last_entity(struct cfs_rq *cfs_rq) |
aeb73b04 | 548 | { |
7eee3e67 | 549 | struct rb_node *last = rb_last(&cfs_rq->tasks_timeline); |
aeb73b04 | 550 | |
70eee74b BS |
551 | if (!last) |
552 | return NULL; | |
7eee3e67 IM |
553 | |
554 | return rb_entry(last, struct sched_entity, run_node); | |
aeb73b04 PZ |
555 | } |
556 | ||
bf0f6f24 IM |
557 | /************************************************************** |
558 | * Scheduling class statistics methods: | |
559 | */ | |
560 | ||
acb4a848 | 561 | int sched_proc_update_handler(struct ctl_table *table, int write, |
8d65af78 | 562 | void __user *buffer, size_t *lenp, |
b2be5e96 PZ |
563 | loff_t *ppos) |
564 | { | |
8d65af78 | 565 | int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); |
acb4a848 | 566 | int factor = get_update_sysctl_factor(); |
b2be5e96 PZ |
567 | |
568 | if (ret || !write) | |
569 | return ret; | |
570 | ||
571 | sched_nr_latency = DIV_ROUND_UP(sysctl_sched_latency, | |
572 | sysctl_sched_min_granularity); | |
573 | ||
acb4a848 CE |
574 | #define WRT_SYSCTL(name) \ |
575 | (normalized_sysctl_##name = sysctl_##name / (factor)) | |
576 | WRT_SYSCTL(sched_min_granularity); | |
577 | WRT_SYSCTL(sched_latency); | |
578 | WRT_SYSCTL(sched_wakeup_granularity); | |
acb4a848 CE |
579 | #undef WRT_SYSCTL |
580 | ||
b2be5e96 PZ |
581 | return 0; |
582 | } | |
583 | #endif | |
647e7cac | 584 | |
a7be37ac | 585 | /* |
f9c0b095 | 586 | * delta /= w |
a7be37ac PZ |
587 | */ |
588 | static inline unsigned long | |
589 | calc_delta_fair(unsigned long delta, struct sched_entity *se) | |
590 | { | |
f9c0b095 PZ |
591 | if (unlikely(se->load.weight != NICE_0_LOAD)) |
592 | delta = calc_delta_mine(delta, NICE_0_LOAD, &se->load); | |
a7be37ac PZ |
593 | |
594 | return delta; | |
595 | } | |
596 | ||
647e7cac IM |
597 | /* |
598 | * The idea is to set a period in which each task runs once. | |
599 | * | |
600 | * When there are too many tasks (sysctl_sched_nr_latency) we have to stretch | |
601 | * this period because otherwise the slices get too small. | |
602 | * | |
603 | * p = (nr <= nl) ? l : l*nr/nl | |
604 | */ | |
4d78e7b6 PZ |
605 | static u64 __sched_period(unsigned long nr_running) |
606 | { | |
607 | u64 period = sysctl_sched_latency; | |
b2be5e96 | 608 | unsigned long nr_latency = sched_nr_latency; |
4d78e7b6 PZ |
609 | |
610 | if (unlikely(nr_running > nr_latency)) { | |
4bf0b771 | 611 | period = sysctl_sched_min_granularity; |
4d78e7b6 | 612 | period *= nr_running; |
4d78e7b6 PZ |
613 | } |
614 | ||
615 | return period; | |
616 | } | |
617 | ||
647e7cac IM |
618 | /* |
619 | * We calculate the wall-time slice from the period by taking a part | |
620 | * proportional to the weight. | |
621 | * | |
f9c0b095 | 622 | * s = p*P[w/rw] |
647e7cac | 623 | */ |
6d0f0ebd | 624 | static u64 sched_slice(struct cfs_rq *cfs_rq, struct sched_entity *se) |
21805085 | 625 | { |
0a582440 | 626 | u64 slice = __sched_period(cfs_rq->nr_running + !se->on_rq); |
f9c0b095 | 627 | |
0a582440 | 628 | for_each_sched_entity(se) { |
6272d68c | 629 | struct load_weight *load; |
3104bf03 | 630 | struct load_weight lw; |
6272d68c LM |
631 | |
632 | cfs_rq = cfs_rq_of(se); | |
633 | load = &cfs_rq->load; | |
f9c0b095 | 634 | |
0a582440 | 635 | if (unlikely(!se->on_rq)) { |
3104bf03 | 636 | lw = cfs_rq->load; |
0a582440 MG |
637 | |
638 | update_load_add(&lw, se->load.weight); | |
639 | load = &lw; | |
640 | } | |
641 | slice = calc_delta_mine(slice, se->load.weight, load); | |
642 | } | |
643 | return slice; | |
bf0f6f24 IM |
644 | } |
645 | ||
647e7cac | 646 | /* |
ac884dec | 647 | * We calculate the vruntime slice of a to be inserted task |
647e7cac | 648 | * |
f9c0b095 | 649 | * vs = s/w |
647e7cac | 650 | */ |
f9c0b095 | 651 | static u64 sched_vslice(struct cfs_rq *cfs_rq, struct sched_entity *se) |
67e9fb2a | 652 | { |
f9c0b095 | 653 | return calc_delta_fair(sched_slice(cfs_rq, se), se); |
a7be37ac PZ |
654 | } |
655 | ||
d6b55918 | 656 | static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update); |
6d5ab293 | 657 | static void update_cfs_shares(struct cfs_rq *cfs_rq); |
3b3d190e | 658 | |
bf0f6f24 IM |
659 | /* |
660 | * Update the current task's runtime statistics. Skip current tasks that | |
661 | * are not in our scheduling class. | |
662 | */ | |
663 | static inline void | |
8ebc91d9 IM |
664 | __update_curr(struct cfs_rq *cfs_rq, struct sched_entity *curr, |
665 | unsigned long delta_exec) | |
bf0f6f24 | 666 | { |
bbdba7c0 | 667 | unsigned long delta_exec_weighted; |
bf0f6f24 | 668 | |
41acab88 LDM |
669 | schedstat_set(curr->statistics.exec_max, |
670 | max((u64)delta_exec, curr->statistics.exec_max)); | |
bf0f6f24 IM |
671 | |
672 | curr->sum_exec_runtime += delta_exec; | |
7a62eabc | 673 | schedstat_add(cfs_rq, exec_clock, delta_exec); |
a7be37ac | 674 | delta_exec_weighted = calc_delta_fair(delta_exec, curr); |
88ec22d3 | 675 | |
e9acbff6 | 676 | curr->vruntime += delta_exec_weighted; |
1af5f730 | 677 | update_min_vruntime(cfs_rq); |
3b3d190e | 678 | |
70caf8a6 | 679 | #if defined CONFIG_SMP && defined CONFIG_FAIR_GROUP_SCHED |
3b3d190e | 680 | cfs_rq->load_unacc_exec_time += delta_exec; |
3b3d190e | 681 | #endif |
bf0f6f24 IM |
682 | } |
683 | ||
b7cc0896 | 684 | static void update_curr(struct cfs_rq *cfs_rq) |
bf0f6f24 | 685 | { |
429d43bc | 686 | struct sched_entity *curr = cfs_rq->curr; |
305e6835 | 687 | u64 now = rq_of(cfs_rq)->clock_task; |
bf0f6f24 IM |
688 | unsigned long delta_exec; |
689 | ||
690 | if (unlikely(!curr)) | |
691 | return; | |
692 | ||
693 | /* | |
694 | * Get the amount of time the current task was running | |
695 | * since the last time we changed load (this cannot | |
696 | * overflow on 32 bits): | |
697 | */ | |
8ebc91d9 | 698 | delta_exec = (unsigned long)(now - curr->exec_start); |
34f28ecd PZ |
699 | if (!delta_exec) |
700 | return; | |
bf0f6f24 | 701 | |
8ebc91d9 IM |
702 | __update_curr(cfs_rq, curr, delta_exec); |
703 | curr->exec_start = now; | |
d842de87 SV |
704 | |
705 | if (entity_is_task(curr)) { | |
706 | struct task_struct *curtask = task_of(curr); | |
707 | ||
f977bb49 | 708 | trace_sched_stat_runtime(curtask, delta_exec, curr->vruntime); |
d842de87 | 709 | cpuacct_charge(curtask, delta_exec); |
f06febc9 | 710 | account_group_exec_runtime(curtask, delta_exec); |
d842de87 | 711 | } |
ec12cb7f PT |
712 | |
713 | account_cfs_rq_runtime(cfs_rq, delta_exec); | |
bf0f6f24 IM |
714 | } |
715 | ||
716 | static inline void | |
5870db5b | 717 | update_stats_wait_start(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 718 | { |
41acab88 | 719 | schedstat_set(se->statistics.wait_start, rq_of(cfs_rq)->clock); |
bf0f6f24 IM |
720 | } |
721 | ||
bf0f6f24 IM |
722 | /* |
723 | * Task is being enqueued - update stats: | |
724 | */ | |
d2417e5a | 725 | static void update_stats_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 726 | { |
bf0f6f24 IM |
727 | /* |
728 | * Are we enqueueing a waiting task? (for current tasks | |
729 | * a dequeue/enqueue event is a NOP) | |
730 | */ | |
429d43bc | 731 | if (se != cfs_rq->curr) |
5870db5b | 732 | update_stats_wait_start(cfs_rq, se); |
bf0f6f24 IM |
733 | } |
734 | ||
bf0f6f24 | 735 | static void |
9ef0a961 | 736 | update_stats_wait_end(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 737 | { |
41acab88 LDM |
738 | schedstat_set(se->statistics.wait_max, max(se->statistics.wait_max, |
739 | rq_of(cfs_rq)->clock - se->statistics.wait_start)); | |
740 | schedstat_set(se->statistics.wait_count, se->statistics.wait_count + 1); | |
741 | schedstat_set(se->statistics.wait_sum, se->statistics.wait_sum + | |
742 | rq_of(cfs_rq)->clock - se->statistics.wait_start); | |
768d0c27 PZ |
743 | #ifdef CONFIG_SCHEDSTATS |
744 | if (entity_is_task(se)) { | |
745 | trace_sched_stat_wait(task_of(se), | |
41acab88 | 746 | rq_of(cfs_rq)->clock - se->statistics.wait_start); |
768d0c27 PZ |
747 | } |
748 | #endif | |
41acab88 | 749 | schedstat_set(se->statistics.wait_start, 0); |
bf0f6f24 IM |
750 | } |
751 | ||
752 | static inline void | |
19b6a2e3 | 753 | update_stats_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 754 | { |
bf0f6f24 IM |
755 | /* |
756 | * Mark the end of the wait period if dequeueing a | |
757 | * waiting task: | |
758 | */ | |
429d43bc | 759 | if (se != cfs_rq->curr) |
9ef0a961 | 760 | update_stats_wait_end(cfs_rq, se); |
bf0f6f24 IM |
761 | } |
762 | ||
763 | /* | |
764 | * We are picking a new current task - update its stats: | |
765 | */ | |
766 | static inline void | |
79303e9e | 767 | update_stats_curr_start(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 IM |
768 | { |
769 | /* | |
770 | * We are starting a new run period: | |
771 | */ | |
305e6835 | 772 | se->exec_start = rq_of(cfs_rq)->clock_task; |
bf0f6f24 IM |
773 | } |
774 | ||
bf0f6f24 IM |
775 | /************************************************** |
776 | * Scheduling class queueing methods: | |
777 | */ | |
778 | ||
c09595f6 PZ |
779 | #if defined CONFIG_SMP && defined CONFIG_FAIR_GROUP_SCHED |
780 | static void | |
781 | add_cfs_task_weight(struct cfs_rq *cfs_rq, unsigned long weight) | |
782 | { | |
783 | cfs_rq->task_weight += weight; | |
784 | } | |
785 | #else | |
786 | static inline void | |
787 | add_cfs_task_weight(struct cfs_rq *cfs_rq, unsigned long weight) | |
788 | { | |
789 | } | |
790 | #endif | |
791 | ||
30cfdcfc DA |
792 | static void |
793 | account_entity_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se) | |
794 | { | |
795 | update_load_add(&cfs_rq->load, se->load.weight); | |
c09595f6 | 796 | if (!parent_entity(se)) |
029632fb | 797 | update_load_add(&rq_of(cfs_rq)->load, se->load.weight); |
b87f1724 | 798 | if (entity_is_task(se)) { |
c09595f6 | 799 | add_cfs_task_weight(cfs_rq, se->load.weight); |
b87f1724 BR |
800 | list_add(&se->group_node, &cfs_rq->tasks); |
801 | } | |
30cfdcfc | 802 | cfs_rq->nr_running++; |
30cfdcfc DA |
803 | } |
804 | ||
805 | static void | |
806 | account_entity_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se) | |
807 | { | |
808 | update_load_sub(&cfs_rq->load, se->load.weight); | |
c09595f6 | 809 | if (!parent_entity(se)) |
029632fb | 810 | update_load_sub(&rq_of(cfs_rq)->load, se->load.weight); |
b87f1724 | 811 | if (entity_is_task(se)) { |
c09595f6 | 812 | add_cfs_task_weight(cfs_rq, -se->load.weight); |
b87f1724 BR |
813 | list_del_init(&se->group_node); |
814 | } | |
30cfdcfc | 815 | cfs_rq->nr_running--; |
30cfdcfc DA |
816 | } |
817 | ||
3ff6dcac | 818 | #ifdef CONFIG_FAIR_GROUP_SCHED |
64660c86 PT |
819 | /* we need this in update_cfs_load and load-balance functions below */ |
820 | static inline int throttled_hierarchy(struct cfs_rq *cfs_rq); | |
3ff6dcac | 821 | # ifdef CONFIG_SMP |
d6b55918 PT |
822 | static void update_cfs_rq_load_contribution(struct cfs_rq *cfs_rq, |
823 | int global_update) | |
824 | { | |
825 | struct task_group *tg = cfs_rq->tg; | |
826 | long load_avg; | |
827 | ||
828 | load_avg = div64_u64(cfs_rq->load_avg, cfs_rq->load_period+1); | |
829 | load_avg -= cfs_rq->load_contribution; | |
830 | ||
831 | if (global_update || abs(load_avg) > cfs_rq->load_contribution / 8) { | |
832 | atomic_add(load_avg, &tg->load_weight); | |
833 | cfs_rq->load_contribution += load_avg; | |
834 | } | |
835 | } | |
836 | ||
837 | static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update) | |
2069dd75 | 838 | { |
a7a4f8a7 | 839 | u64 period = sysctl_sched_shares_window; |
2069dd75 | 840 | u64 now, delta; |
e33078ba | 841 | unsigned long load = cfs_rq->load.weight; |
2069dd75 | 842 | |
64660c86 | 843 | if (cfs_rq->tg == &root_task_group || throttled_hierarchy(cfs_rq)) |
2069dd75 PZ |
844 | return; |
845 | ||
05ca62c6 | 846 | now = rq_of(cfs_rq)->clock_task; |
2069dd75 PZ |
847 | delta = now - cfs_rq->load_stamp; |
848 | ||
e33078ba PT |
849 | /* truncate load history at 4 idle periods */ |
850 | if (cfs_rq->load_stamp > cfs_rq->load_last && | |
851 | now - cfs_rq->load_last > 4 * period) { | |
852 | cfs_rq->load_period = 0; | |
853 | cfs_rq->load_avg = 0; | |
f07333bf | 854 | delta = period - 1; |
e33078ba PT |
855 | } |
856 | ||
2069dd75 | 857 | cfs_rq->load_stamp = now; |
3b3d190e | 858 | cfs_rq->load_unacc_exec_time = 0; |
2069dd75 | 859 | cfs_rq->load_period += delta; |
e33078ba PT |
860 | if (load) { |
861 | cfs_rq->load_last = now; | |
862 | cfs_rq->load_avg += delta * load; | |
863 | } | |
2069dd75 | 864 | |
d6b55918 PT |
865 | /* consider updating load contribution on each fold or truncate */ |
866 | if (global_update || cfs_rq->load_period > period | |
867 | || !cfs_rq->load_period) | |
868 | update_cfs_rq_load_contribution(cfs_rq, global_update); | |
869 | ||
2069dd75 PZ |
870 | while (cfs_rq->load_period > period) { |
871 | /* | |
872 | * Inline assembly required to prevent the compiler | |
873 | * optimising this loop into a divmod call. | |
874 | * See __iter_div_u64_rem() for another example of this. | |
875 | */ | |
876 | asm("" : "+rm" (cfs_rq->load_period)); | |
877 | cfs_rq->load_period /= 2; | |
878 | cfs_rq->load_avg /= 2; | |
879 | } | |
3d4b47b4 | 880 | |
e33078ba PT |
881 | if (!cfs_rq->curr && !cfs_rq->nr_running && !cfs_rq->load_avg) |
882 | list_del_leaf_cfs_rq(cfs_rq); | |
2069dd75 PZ |
883 | } |
884 | ||
cf5f0acf PZ |
885 | static inline long calc_tg_weight(struct task_group *tg, struct cfs_rq *cfs_rq) |
886 | { | |
887 | long tg_weight; | |
888 | ||
889 | /* | |
890 | * Use this CPU's actual weight instead of the last load_contribution | |
891 | * to gain a more accurate current total weight. See | |
892 | * update_cfs_rq_load_contribution(). | |
893 | */ | |
894 | tg_weight = atomic_read(&tg->load_weight); | |
895 | tg_weight -= cfs_rq->load_contribution; | |
896 | tg_weight += cfs_rq->load.weight; | |
897 | ||
898 | return tg_weight; | |
899 | } | |
900 | ||
6d5ab293 | 901 | static long calc_cfs_shares(struct cfs_rq *cfs_rq, struct task_group *tg) |
3ff6dcac | 902 | { |
cf5f0acf | 903 | long tg_weight, load, shares; |
3ff6dcac | 904 | |
cf5f0acf | 905 | tg_weight = calc_tg_weight(tg, cfs_rq); |
6d5ab293 | 906 | load = cfs_rq->load.weight; |
3ff6dcac | 907 | |
3ff6dcac | 908 | shares = (tg->shares * load); |
cf5f0acf PZ |
909 | if (tg_weight) |
910 | shares /= tg_weight; | |
3ff6dcac YZ |
911 | |
912 | if (shares < MIN_SHARES) | |
913 | shares = MIN_SHARES; | |
914 | if (shares > tg->shares) | |
915 | shares = tg->shares; | |
916 | ||
917 | return shares; | |
918 | } | |
919 | ||
920 | static void update_entity_shares_tick(struct cfs_rq *cfs_rq) | |
921 | { | |
922 | if (cfs_rq->load_unacc_exec_time > sysctl_sched_shares_window) { | |
923 | update_cfs_load(cfs_rq, 0); | |
6d5ab293 | 924 | update_cfs_shares(cfs_rq); |
3ff6dcac YZ |
925 | } |
926 | } | |
927 | # else /* CONFIG_SMP */ | |
928 | static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update) | |
929 | { | |
930 | } | |
931 | ||
6d5ab293 | 932 | static inline long calc_cfs_shares(struct cfs_rq *cfs_rq, struct task_group *tg) |
3ff6dcac YZ |
933 | { |
934 | return tg->shares; | |
935 | } | |
936 | ||
937 | static inline void update_entity_shares_tick(struct cfs_rq *cfs_rq) | |
938 | { | |
939 | } | |
940 | # endif /* CONFIG_SMP */ | |
2069dd75 PZ |
941 | static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, |
942 | unsigned long weight) | |
943 | { | |
19e5eebb PT |
944 | if (se->on_rq) { |
945 | /* commit outstanding execution time */ | |
946 | if (cfs_rq->curr == se) | |
947 | update_curr(cfs_rq); | |
2069dd75 | 948 | account_entity_dequeue(cfs_rq, se); |
19e5eebb | 949 | } |
2069dd75 PZ |
950 | |
951 | update_load_set(&se->load, weight); | |
952 | ||
953 | if (se->on_rq) | |
954 | account_entity_enqueue(cfs_rq, se); | |
955 | } | |
956 | ||
6d5ab293 | 957 | static void update_cfs_shares(struct cfs_rq *cfs_rq) |
2069dd75 PZ |
958 | { |
959 | struct task_group *tg; | |
960 | struct sched_entity *se; | |
3ff6dcac | 961 | long shares; |
2069dd75 | 962 | |
2069dd75 PZ |
963 | tg = cfs_rq->tg; |
964 | se = tg->se[cpu_of(rq_of(cfs_rq))]; | |
64660c86 | 965 | if (!se || throttled_hierarchy(cfs_rq)) |
2069dd75 | 966 | return; |
3ff6dcac YZ |
967 | #ifndef CONFIG_SMP |
968 | if (likely(se->load.weight == tg->shares)) | |
969 | return; | |
970 | #endif | |
6d5ab293 | 971 | shares = calc_cfs_shares(cfs_rq, tg); |
2069dd75 PZ |
972 | |
973 | reweight_entity(cfs_rq_of(se), se, shares); | |
974 | } | |
975 | #else /* CONFIG_FAIR_GROUP_SCHED */ | |
d6b55918 | 976 | static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update) |
2069dd75 PZ |
977 | { |
978 | } | |
979 | ||
6d5ab293 | 980 | static inline void update_cfs_shares(struct cfs_rq *cfs_rq) |
2069dd75 PZ |
981 | { |
982 | } | |
43365bd7 PT |
983 | |
984 | static inline void update_entity_shares_tick(struct cfs_rq *cfs_rq) | |
985 | { | |
986 | } | |
2069dd75 PZ |
987 | #endif /* CONFIG_FAIR_GROUP_SCHED */ |
988 | ||
2396af69 | 989 | static void enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 990 | { |
bf0f6f24 | 991 | #ifdef CONFIG_SCHEDSTATS |
e414314c PZ |
992 | struct task_struct *tsk = NULL; |
993 | ||
994 | if (entity_is_task(se)) | |
995 | tsk = task_of(se); | |
996 | ||
41acab88 LDM |
997 | if (se->statistics.sleep_start) { |
998 | u64 delta = rq_of(cfs_rq)->clock - se->statistics.sleep_start; | |
bf0f6f24 IM |
999 | |
1000 | if ((s64)delta < 0) | |
1001 | delta = 0; | |
1002 | ||
41acab88 LDM |
1003 | if (unlikely(delta > se->statistics.sleep_max)) |
1004 | se->statistics.sleep_max = delta; | |
bf0f6f24 | 1005 | |
41acab88 LDM |
1006 | se->statistics.sleep_start = 0; |
1007 | se->statistics.sum_sleep_runtime += delta; | |
9745512c | 1008 | |
768d0c27 | 1009 | if (tsk) { |
e414314c | 1010 | account_scheduler_latency(tsk, delta >> 10, 1); |
768d0c27 PZ |
1011 | trace_sched_stat_sleep(tsk, delta); |
1012 | } | |
bf0f6f24 | 1013 | } |
41acab88 LDM |
1014 | if (se->statistics.block_start) { |
1015 | u64 delta = rq_of(cfs_rq)->clock - se->statistics.block_start; | |
bf0f6f24 IM |
1016 | |
1017 | if ((s64)delta < 0) | |
1018 | delta = 0; | |
1019 | ||
41acab88 LDM |
1020 | if (unlikely(delta > se->statistics.block_max)) |
1021 | se->statistics.block_max = delta; | |
bf0f6f24 | 1022 | |
41acab88 LDM |
1023 | se->statistics.block_start = 0; |
1024 | se->statistics.sum_sleep_runtime += delta; | |
30084fbd | 1025 | |
e414314c | 1026 | if (tsk) { |
8f0dfc34 | 1027 | if (tsk->in_iowait) { |
41acab88 LDM |
1028 | se->statistics.iowait_sum += delta; |
1029 | se->statistics.iowait_count++; | |
768d0c27 | 1030 | trace_sched_stat_iowait(tsk, delta); |
8f0dfc34 AV |
1031 | } |
1032 | ||
e414314c PZ |
1033 | /* |
1034 | * Blocking time is in units of nanosecs, so shift by | |
1035 | * 20 to get a milliseconds-range estimation of the | |
1036 | * amount of time that the task spent sleeping: | |
1037 | */ | |
1038 | if (unlikely(prof_on == SLEEP_PROFILING)) { | |
1039 | profile_hits(SLEEP_PROFILING, | |
1040 | (void *)get_wchan(tsk), | |
1041 | delta >> 20); | |
1042 | } | |
1043 | account_scheduler_latency(tsk, delta >> 10, 0); | |
30084fbd | 1044 | } |
bf0f6f24 IM |
1045 | } |
1046 | #endif | |
1047 | } | |
1048 | ||
ddc97297 PZ |
1049 | static void check_spread(struct cfs_rq *cfs_rq, struct sched_entity *se) |
1050 | { | |
1051 | #ifdef CONFIG_SCHED_DEBUG | |
1052 | s64 d = se->vruntime - cfs_rq->min_vruntime; | |
1053 | ||
1054 | if (d < 0) | |
1055 | d = -d; | |
1056 | ||
1057 | if (d > 3*sysctl_sched_latency) | |
1058 | schedstat_inc(cfs_rq, nr_spread_over); | |
1059 | #endif | |
1060 | } | |
1061 | ||
aeb73b04 PZ |
1062 | static void |
1063 | place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial) | |
1064 | { | |
1af5f730 | 1065 | u64 vruntime = cfs_rq->min_vruntime; |
94dfb5e7 | 1066 | |
2cb8600e PZ |
1067 | /* |
1068 | * The 'current' period is already promised to the current tasks, | |
1069 | * however the extra weight of the new task will slow them down a | |
1070 | * little, place the new task so that it fits in the slot that | |
1071 | * stays open at the end. | |
1072 | */ | |
94dfb5e7 | 1073 | if (initial && sched_feat(START_DEBIT)) |
f9c0b095 | 1074 | vruntime += sched_vslice(cfs_rq, se); |
aeb73b04 | 1075 | |
a2e7a7eb | 1076 | /* sleeps up to a single latency don't count. */ |
5ca9880c | 1077 | if (!initial) { |
a2e7a7eb | 1078 | unsigned long thresh = sysctl_sched_latency; |
a7be37ac | 1079 | |
a2e7a7eb MG |
1080 | /* |
1081 | * Halve their sleep time's effect, to allow | |
1082 | * for a gentler effect of sleepers: | |
1083 | */ | |
1084 | if (sched_feat(GENTLE_FAIR_SLEEPERS)) | |
1085 | thresh >>= 1; | |
51e0304c | 1086 | |
a2e7a7eb | 1087 | vruntime -= thresh; |
aeb73b04 PZ |
1088 | } |
1089 | ||
b5d9d734 MG |
1090 | /* ensure we never gain time by being placed backwards. */ |
1091 | vruntime = max_vruntime(se->vruntime, vruntime); | |
1092 | ||
67e9fb2a | 1093 | se->vruntime = vruntime; |
aeb73b04 PZ |
1094 | } |
1095 | ||
d3d9dc33 PT |
1096 | static void check_enqueue_throttle(struct cfs_rq *cfs_rq); |
1097 | ||
bf0f6f24 | 1098 | static void |
88ec22d3 | 1099 | enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) |
bf0f6f24 | 1100 | { |
88ec22d3 PZ |
1101 | /* |
1102 | * Update the normalized vruntime before updating min_vruntime | |
1103 | * through callig update_curr(). | |
1104 | */ | |
371fd7e7 | 1105 | if (!(flags & ENQUEUE_WAKEUP) || (flags & ENQUEUE_WAKING)) |
88ec22d3 PZ |
1106 | se->vruntime += cfs_rq->min_vruntime; |
1107 | ||
bf0f6f24 | 1108 | /* |
a2a2d680 | 1109 | * Update run-time statistics of the 'current'. |
bf0f6f24 | 1110 | */ |
b7cc0896 | 1111 | update_curr(cfs_rq); |
d6b55918 | 1112 | update_cfs_load(cfs_rq, 0); |
a992241d | 1113 | account_entity_enqueue(cfs_rq, se); |
6d5ab293 | 1114 | update_cfs_shares(cfs_rq); |
bf0f6f24 | 1115 | |
88ec22d3 | 1116 | if (flags & ENQUEUE_WAKEUP) { |
aeb73b04 | 1117 | place_entity(cfs_rq, se, 0); |
2396af69 | 1118 | enqueue_sleeper(cfs_rq, se); |
e9acbff6 | 1119 | } |
bf0f6f24 | 1120 | |
d2417e5a | 1121 | update_stats_enqueue(cfs_rq, se); |
ddc97297 | 1122 | check_spread(cfs_rq, se); |
83b699ed SV |
1123 | if (se != cfs_rq->curr) |
1124 | __enqueue_entity(cfs_rq, se); | |
2069dd75 | 1125 | se->on_rq = 1; |
3d4b47b4 | 1126 | |
d3d9dc33 | 1127 | if (cfs_rq->nr_running == 1) { |
3d4b47b4 | 1128 | list_add_leaf_cfs_rq(cfs_rq); |
d3d9dc33 PT |
1129 | check_enqueue_throttle(cfs_rq); |
1130 | } | |
bf0f6f24 IM |
1131 | } |
1132 | ||
2c13c919 | 1133 | static void __clear_buddies_last(struct sched_entity *se) |
2002c695 | 1134 | { |
2c13c919 RR |
1135 | for_each_sched_entity(se) { |
1136 | struct cfs_rq *cfs_rq = cfs_rq_of(se); | |
1137 | if (cfs_rq->last == se) | |
1138 | cfs_rq->last = NULL; | |
1139 | else | |
1140 | break; | |
1141 | } | |
1142 | } | |
2002c695 | 1143 | |
2c13c919 RR |
1144 | static void __clear_buddies_next(struct sched_entity *se) |
1145 | { | |
1146 | for_each_sched_entity(se) { | |
1147 | struct cfs_rq *cfs_rq = cfs_rq_of(se); | |
1148 | if (cfs_rq->next == se) | |
1149 | cfs_rq->next = NULL; | |
1150 | else | |
1151 | break; | |
1152 | } | |
2002c695 PZ |
1153 | } |
1154 | ||
ac53db59 RR |
1155 | static void __clear_buddies_skip(struct sched_entity *se) |
1156 | { | |
1157 | for_each_sched_entity(se) { | |
1158 | struct cfs_rq *cfs_rq = cfs_rq_of(se); | |
1159 | if (cfs_rq->skip == se) | |
1160 | cfs_rq->skip = NULL; | |
1161 | else | |
1162 | break; | |
1163 | } | |
1164 | } | |
1165 | ||
a571bbea PZ |
1166 | static void clear_buddies(struct cfs_rq *cfs_rq, struct sched_entity *se) |
1167 | { | |
2c13c919 RR |
1168 | if (cfs_rq->last == se) |
1169 | __clear_buddies_last(se); | |
1170 | ||
1171 | if (cfs_rq->next == se) | |
1172 | __clear_buddies_next(se); | |
ac53db59 RR |
1173 | |
1174 | if (cfs_rq->skip == se) | |
1175 | __clear_buddies_skip(se); | |
a571bbea PZ |
1176 | } |
1177 | ||
d8b4986d PT |
1178 | static void return_cfs_rq_runtime(struct cfs_rq *cfs_rq); |
1179 | ||
bf0f6f24 | 1180 | static void |
371fd7e7 | 1181 | dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) |
bf0f6f24 | 1182 | { |
a2a2d680 DA |
1183 | /* |
1184 | * Update run-time statistics of the 'current'. | |
1185 | */ | |
1186 | update_curr(cfs_rq); | |
1187 | ||
19b6a2e3 | 1188 | update_stats_dequeue(cfs_rq, se); |
371fd7e7 | 1189 | if (flags & DEQUEUE_SLEEP) { |
67e9fb2a | 1190 | #ifdef CONFIG_SCHEDSTATS |
bf0f6f24 IM |
1191 | if (entity_is_task(se)) { |
1192 | struct task_struct *tsk = task_of(se); | |
1193 | ||
1194 | if (tsk->state & TASK_INTERRUPTIBLE) | |
41acab88 | 1195 | se->statistics.sleep_start = rq_of(cfs_rq)->clock; |
bf0f6f24 | 1196 | if (tsk->state & TASK_UNINTERRUPTIBLE) |
41acab88 | 1197 | se->statistics.block_start = rq_of(cfs_rq)->clock; |
bf0f6f24 | 1198 | } |
db36cc7d | 1199 | #endif |
67e9fb2a PZ |
1200 | } |
1201 | ||
2002c695 | 1202 | clear_buddies(cfs_rq, se); |
4793241b | 1203 | |
83b699ed | 1204 | if (se != cfs_rq->curr) |
30cfdcfc | 1205 | __dequeue_entity(cfs_rq, se); |
2069dd75 | 1206 | se->on_rq = 0; |
d6b55918 | 1207 | update_cfs_load(cfs_rq, 0); |
30cfdcfc | 1208 | account_entity_dequeue(cfs_rq, se); |
88ec22d3 PZ |
1209 | |
1210 | /* | |
1211 | * Normalize the entity after updating the min_vruntime because the | |
1212 | * update can refer to the ->curr item and we need to reflect this | |
1213 | * movement in our normalized position. | |
1214 | */ | |
371fd7e7 | 1215 | if (!(flags & DEQUEUE_SLEEP)) |
88ec22d3 | 1216 | se->vruntime -= cfs_rq->min_vruntime; |
1e876231 | 1217 | |
d8b4986d PT |
1218 | /* return excess runtime on last dequeue */ |
1219 | return_cfs_rq_runtime(cfs_rq); | |
1220 | ||
1e876231 PZ |
1221 | update_min_vruntime(cfs_rq); |
1222 | update_cfs_shares(cfs_rq); | |
bf0f6f24 IM |
1223 | } |
1224 | ||
1225 | /* | |
1226 | * Preempt the current task with a newly woken task if needed: | |
1227 | */ | |
7c92e54f | 1228 | static void |
2e09bf55 | 1229 | check_preempt_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr) |
bf0f6f24 | 1230 | { |
11697830 | 1231 | unsigned long ideal_runtime, delta_exec; |
f4cfb33e WX |
1232 | struct sched_entity *se; |
1233 | s64 delta; | |
11697830 | 1234 | |
6d0f0ebd | 1235 | ideal_runtime = sched_slice(cfs_rq, curr); |
11697830 | 1236 | delta_exec = curr->sum_exec_runtime - curr->prev_sum_exec_runtime; |
a9f3e2b5 | 1237 | if (delta_exec > ideal_runtime) { |
bf0f6f24 | 1238 | resched_task(rq_of(cfs_rq)->curr); |
a9f3e2b5 MG |
1239 | /* |
1240 | * The current task ran long enough, ensure it doesn't get | |
1241 | * re-elected due to buddy favours. | |
1242 | */ | |
1243 | clear_buddies(cfs_rq, curr); | |
f685ceac MG |
1244 | return; |
1245 | } | |
1246 | ||
1247 | /* | |
1248 | * Ensure that a task that missed wakeup preemption by a | |
1249 | * narrow margin doesn't have to wait for a full slice. | |
1250 | * This also mitigates buddy induced latencies under load. | |
1251 | */ | |
f685ceac MG |
1252 | if (delta_exec < sysctl_sched_min_granularity) |
1253 | return; | |
1254 | ||
f4cfb33e WX |
1255 | se = __pick_first_entity(cfs_rq); |
1256 | delta = curr->vruntime - se->vruntime; | |
f685ceac | 1257 | |
f4cfb33e WX |
1258 | if (delta < 0) |
1259 | return; | |
d7d82944 | 1260 | |
f4cfb33e WX |
1261 | if (delta > ideal_runtime) |
1262 | resched_task(rq_of(cfs_rq)->curr); | |
bf0f6f24 IM |
1263 | } |
1264 | ||
83b699ed | 1265 | static void |
8494f412 | 1266 | set_next_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 1267 | { |
83b699ed SV |
1268 | /* 'current' is not kept within the tree. */ |
1269 | if (se->on_rq) { | |
1270 | /* | |
1271 | * Any task has to be enqueued before it get to execute on | |
1272 | * a CPU. So account for the time it spent waiting on the | |
1273 | * runqueue. | |
1274 | */ | |
1275 | update_stats_wait_end(cfs_rq, se); | |
1276 | __dequeue_entity(cfs_rq, se); | |
1277 | } | |
1278 | ||
79303e9e | 1279 | update_stats_curr_start(cfs_rq, se); |
429d43bc | 1280 | cfs_rq->curr = se; |
eba1ed4b IM |
1281 | #ifdef CONFIG_SCHEDSTATS |
1282 | /* | |
1283 | * Track our maximum slice length, if the CPU's load is at | |
1284 | * least twice that of our own weight (i.e. dont track it | |
1285 | * when there are only lesser-weight tasks around): | |
1286 | */ | |
495eca49 | 1287 | if (rq_of(cfs_rq)->load.weight >= 2*se->load.weight) { |
41acab88 | 1288 | se->statistics.slice_max = max(se->statistics.slice_max, |
eba1ed4b IM |
1289 | se->sum_exec_runtime - se->prev_sum_exec_runtime); |
1290 | } | |
1291 | #endif | |
4a55b450 | 1292 | se->prev_sum_exec_runtime = se->sum_exec_runtime; |
bf0f6f24 IM |
1293 | } |
1294 | ||
3f3a4904 PZ |
1295 | static int |
1296 | wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se); | |
1297 | ||
ac53db59 RR |
1298 | /* |
1299 | * Pick the next process, keeping these things in mind, in this order: | |
1300 | * 1) keep things fair between processes/task groups | |
1301 | * 2) pick the "next" process, since someone really wants that to run | |
1302 | * 3) pick the "last" process, for cache locality | |
1303 | * 4) do not run the "skip" process, if something else is available | |
1304 | */ | |
f4b6755f | 1305 | static struct sched_entity *pick_next_entity(struct cfs_rq *cfs_rq) |
aa2ac252 | 1306 | { |
ac53db59 | 1307 | struct sched_entity *se = __pick_first_entity(cfs_rq); |
f685ceac | 1308 | struct sched_entity *left = se; |
f4b6755f | 1309 | |
ac53db59 RR |
1310 | /* |
1311 | * Avoid running the skip buddy, if running something else can | |
1312 | * be done without getting too unfair. | |
1313 | */ | |
1314 | if (cfs_rq->skip == se) { | |
1315 | struct sched_entity *second = __pick_next_entity(se); | |
1316 | if (second && wakeup_preempt_entity(second, left) < 1) | |
1317 | se = second; | |
1318 | } | |
aa2ac252 | 1319 | |
f685ceac MG |
1320 | /* |
1321 | * Prefer last buddy, try to return the CPU to a preempted task. | |
1322 | */ | |
1323 | if (cfs_rq->last && wakeup_preempt_entity(cfs_rq->last, left) < 1) | |
1324 | se = cfs_rq->last; | |
1325 | ||
ac53db59 RR |
1326 | /* |
1327 | * Someone really wants this to run. If it's not unfair, run it. | |
1328 | */ | |
1329 | if (cfs_rq->next && wakeup_preempt_entity(cfs_rq->next, left) < 1) | |
1330 | se = cfs_rq->next; | |
1331 | ||
f685ceac | 1332 | clear_buddies(cfs_rq, se); |
4793241b PZ |
1333 | |
1334 | return se; | |
aa2ac252 PZ |
1335 | } |
1336 | ||
d3d9dc33 PT |
1337 | static void check_cfs_rq_runtime(struct cfs_rq *cfs_rq); |
1338 | ||
ab6cde26 | 1339 | static void put_prev_entity(struct cfs_rq *cfs_rq, struct sched_entity *prev) |
bf0f6f24 IM |
1340 | { |
1341 | /* | |
1342 | * If still on the runqueue then deactivate_task() | |
1343 | * was not called and update_curr() has to be done: | |
1344 | */ | |
1345 | if (prev->on_rq) | |
b7cc0896 | 1346 | update_curr(cfs_rq); |
bf0f6f24 | 1347 | |
d3d9dc33 PT |
1348 | /* throttle cfs_rqs exceeding runtime */ |
1349 | check_cfs_rq_runtime(cfs_rq); | |
1350 | ||
ddc97297 | 1351 | check_spread(cfs_rq, prev); |
30cfdcfc | 1352 | if (prev->on_rq) { |
5870db5b | 1353 | update_stats_wait_start(cfs_rq, prev); |
30cfdcfc DA |
1354 | /* Put 'current' back into the tree. */ |
1355 | __enqueue_entity(cfs_rq, prev); | |
1356 | } | |
429d43bc | 1357 | cfs_rq->curr = NULL; |
bf0f6f24 IM |
1358 | } |
1359 | ||
8f4d37ec PZ |
1360 | static void |
1361 | entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr, int queued) | |
bf0f6f24 | 1362 | { |
bf0f6f24 | 1363 | /* |
30cfdcfc | 1364 | * Update run-time statistics of the 'current'. |
bf0f6f24 | 1365 | */ |
30cfdcfc | 1366 | update_curr(cfs_rq); |
bf0f6f24 | 1367 | |
43365bd7 PT |
1368 | /* |
1369 | * Update share accounting for long-running entities. | |
1370 | */ | |
1371 | update_entity_shares_tick(cfs_rq); | |
1372 | ||
8f4d37ec PZ |
1373 | #ifdef CONFIG_SCHED_HRTICK |
1374 | /* | |
1375 | * queued ticks are scheduled to match the slice, so don't bother | |
1376 | * validating it and just reschedule. | |
1377 | */ | |
983ed7a6 HH |
1378 | if (queued) { |
1379 | resched_task(rq_of(cfs_rq)->curr); | |
1380 | return; | |
1381 | } | |
8f4d37ec PZ |
1382 | /* |
1383 | * don't let the period tick interfere with the hrtick preemption | |
1384 | */ | |
1385 | if (!sched_feat(DOUBLE_TICK) && | |
1386 | hrtimer_active(&rq_of(cfs_rq)->hrtick_timer)) | |
1387 | return; | |
1388 | #endif | |
1389 | ||
2c2efaed | 1390 | if (cfs_rq->nr_running > 1) |
2e09bf55 | 1391 | check_preempt_tick(cfs_rq, curr); |
bf0f6f24 IM |
1392 | } |
1393 | ||
ab84d31e PT |
1394 | |
1395 | /************************************************** | |
1396 | * CFS bandwidth control machinery | |
1397 | */ | |
1398 | ||
1399 | #ifdef CONFIG_CFS_BANDWIDTH | |
029632fb PZ |
1400 | |
1401 | #ifdef HAVE_JUMP_LABEL | |
1402 | static struct jump_label_key __cfs_bandwidth_used; | |
1403 | ||
1404 | static inline bool cfs_bandwidth_used(void) | |
1405 | { | |
1406 | return static_branch(&__cfs_bandwidth_used); | |
1407 | } | |
1408 | ||
1409 | void account_cfs_bandwidth_used(int enabled, int was_enabled) | |
1410 | { | |
1411 | /* only need to count groups transitioning between enabled/!enabled */ | |
1412 | if (enabled && !was_enabled) | |
1413 | jump_label_inc(&__cfs_bandwidth_used); | |
1414 | else if (!enabled && was_enabled) | |
1415 | jump_label_dec(&__cfs_bandwidth_used); | |
1416 | } | |
1417 | #else /* HAVE_JUMP_LABEL */ | |
1418 | static bool cfs_bandwidth_used(void) | |
1419 | { | |
1420 | return true; | |
1421 | } | |
1422 | ||
1423 | void account_cfs_bandwidth_used(int enabled, int was_enabled) {} | |
1424 | #endif /* HAVE_JUMP_LABEL */ | |
1425 | ||
ab84d31e PT |
1426 | /* |
1427 | * default period for cfs group bandwidth. | |
1428 | * default: 0.1s, units: nanoseconds | |
1429 | */ | |
1430 | static inline u64 default_cfs_period(void) | |
1431 | { | |
1432 | return 100000000ULL; | |
1433 | } | |
ec12cb7f PT |
1434 | |
1435 | static inline u64 sched_cfs_bandwidth_slice(void) | |
1436 | { | |
1437 | return (u64)sysctl_sched_cfs_bandwidth_slice * NSEC_PER_USEC; | |
1438 | } | |
1439 | ||
a9cf55b2 PT |
1440 | /* |
1441 | * Replenish runtime according to assigned quota and update expiration time. | |
1442 | * We use sched_clock_cpu directly instead of rq->clock to avoid adding | |
1443 | * additional synchronization around rq->lock. | |
1444 | * | |
1445 | * requires cfs_b->lock | |
1446 | */ | |
029632fb | 1447 | void __refill_cfs_bandwidth_runtime(struct cfs_bandwidth *cfs_b) |
a9cf55b2 PT |
1448 | { |
1449 | u64 now; | |
1450 | ||
1451 | if (cfs_b->quota == RUNTIME_INF) | |
1452 | return; | |
1453 | ||
1454 | now = sched_clock_cpu(smp_processor_id()); | |
1455 | cfs_b->runtime = cfs_b->quota; | |
1456 | cfs_b->runtime_expires = now + ktime_to_ns(cfs_b->period); | |
1457 | } | |
1458 | ||
029632fb PZ |
1459 | static inline struct cfs_bandwidth *tg_cfs_bandwidth(struct task_group *tg) |
1460 | { | |
1461 | return &tg->cfs_bandwidth; | |
1462 | } | |
1463 | ||
85dac906 PT |
1464 | /* returns 0 on failure to allocate runtime */ |
1465 | static int assign_cfs_rq_runtime(struct cfs_rq *cfs_rq) | |
ec12cb7f PT |
1466 | { |
1467 | struct task_group *tg = cfs_rq->tg; | |
1468 | struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(tg); | |
a9cf55b2 | 1469 | u64 amount = 0, min_amount, expires; |
ec12cb7f PT |
1470 | |
1471 | /* note: this is a positive sum as runtime_remaining <= 0 */ | |
1472 | min_amount = sched_cfs_bandwidth_slice() - cfs_rq->runtime_remaining; | |
1473 | ||
1474 | raw_spin_lock(&cfs_b->lock); | |
1475 | if (cfs_b->quota == RUNTIME_INF) | |
1476 | amount = min_amount; | |
58088ad0 | 1477 | else { |
a9cf55b2 PT |
1478 | /* |
1479 | * If the bandwidth pool has become inactive, then at least one | |
1480 | * period must have elapsed since the last consumption. | |
1481 | * Refresh the global state and ensure bandwidth timer becomes | |
1482 | * active. | |
1483 | */ | |
1484 | if (!cfs_b->timer_active) { | |
1485 | __refill_cfs_bandwidth_runtime(cfs_b); | |
58088ad0 | 1486 | __start_cfs_bandwidth(cfs_b); |
a9cf55b2 | 1487 | } |
58088ad0 PT |
1488 | |
1489 | if (cfs_b->runtime > 0) { | |
1490 | amount = min(cfs_b->runtime, min_amount); | |
1491 | cfs_b->runtime -= amount; | |
1492 | cfs_b->idle = 0; | |
1493 | } | |
ec12cb7f | 1494 | } |
a9cf55b2 | 1495 | expires = cfs_b->runtime_expires; |
ec12cb7f PT |
1496 | raw_spin_unlock(&cfs_b->lock); |
1497 | ||
1498 | cfs_rq->runtime_remaining += amount; | |
a9cf55b2 PT |
1499 | /* |
1500 | * we may have advanced our local expiration to account for allowed | |
1501 | * spread between our sched_clock and the one on which runtime was | |
1502 | * issued. | |
1503 | */ | |
1504 | if ((s64)(expires - cfs_rq->runtime_expires) > 0) | |
1505 | cfs_rq->runtime_expires = expires; | |
85dac906 PT |
1506 | |
1507 | return cfs_rq->runtime_remaining > 0; | |
ec12cb7f PT |
1508 | } |
1509 | ||
a9cf55b2 PT |
1510 | /* |
1511 | * Note: This depends on the synchronization provided by sched_clock and the | |
1512 | * fact that rq->clock snapshots this value. | |
1513 | */ | |
1514 | static void expire_cfs_rq_runtime(struct cfs_rq *cfs_rq) | |
ec12cb7f | 1515 | { |
a9cf55b2 PT |
1516 | struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg); |
1517 | struct rq *rq = rq_of(cfs_rq); | |
1518 | ||
1519 | /* if the deadline is ahead of our clock, nothing to do */ | |
1520 | if (likely((s64)(rq->clock - cfs_rq->runtime_expires) < 0)) | |
ec12cb7f PT |
1521 | return; |
1522 | ||
a9cf55b2 PT |
1523 | if (cfs_rq->runtime_remaining < 0) |
1524 | return; | |
1525 | ||
1526 | /* | |
1527 | * If the local deadline has passed we have to consider the | |
1528 | * possibility that our sched_clock is 'fast' and the global deadline | |
1529 | * has not truly expired. | |
1530 | * | |
1531 | * Fortunately we can check determine whether this the case by checking | |
1532 | * whether the global deadline has advanced. | |
1533 | */ | |
1534 | ||
1535 | if ((s64)(cfs_rq->runtime_expires - cfs_b->runtime_expires) >= 0) { | |
1536 | /* extend local deadline, drift is bounded above by 2 ticks */ | |
1537 | cfs_rq->runtime_expires += TICK_NSEC; | |
1538 | } else { | |
1539 | /* global deadline is ahead, expiration has passed */ | |
1540 | cfs_rq->runtime_remaining = 0; | |
1541 | } | |
1542 | } | |
1543 | ||
1544 | static void __account_cfs_rq_runtime(struct cfs_rq *cfs_rq, | |
1545 | unsigned long delta_exec) | |
1546 | { | |
1547 | /* dock delta_exec before expiring quota (as it could span periods) */ | |
ec12cb7f | 1548 | cfs_rq->runtime_remaining -= delta_exec; |
a9cf55b2 PT |
1549 | expire_cfs_rq_runtime(cfs_rq); |
1550 | ||
1551 | if (likely(cfs_rq->runtime_remaining > 0)) | |
ec12cb7f PT |
1552 | return; |
1553 | ||
85dac906 PT |
1554 | /* |
1555 | * if we're unable to extend our runtime we resched so that the active | |
1556 | * hierarchy can be throttled | |
1557 | */ | |
1558 | if (!assign_cfs_rq_runtime(cfs_rq) && likely(cfs_rq->curr)) | |
1559 | resched_task(rq_of(cfs_rq)->curr); | |
ec12cb7f PT |
1560 | } |
1561 | ||
1562 | static __always_inline void account_cfs_rq_runtime(struct cfs_rq *cfs_rq, | |
1563 | unsigned long delta_exec) | |
1564 | { | |
56f570e5 | 1565 | if (!cfs_bandwidth_used() || !cfs_rq->runtime_enabled) |
ec12cb7f PT |
1566 | return; |
1567 | ||
1568 | __account_cfs_rq_runtime(cfs_rq, delta_exec); | |
1569 | } | |
1570 | ||
85dac906 PT |
1571 | static inline int cfs_rq_throttled(struct cfs_rq *cfs_rq) |
1572 | { | |
56f570e5 | 1573 | return cfs_bandwidth_used() && cfs_rq->throttled; |
85dac906 PT |
1574 | } |
1575 | ||
64660c86 PT |
1576 | /* check whether cfs_rq, or any parent, is throttled */ |
1577 | static inline int throttled_hierarchy(struct cfs_rq *cfs_rq) | |
1578 | { | |
56f570e5 | 1579 | return cfs_bandwidth_used() && cfs_rq->throttle_count; |
64660c86 PT |
1580 | } |
1581 | ||
1582 | /* | |
1583 | * Ensure that neither of the group entities corresponding to src_cpu or | |
1584 | * dest_cpu are members of a throttled hierarchy when performing group | |
1585 | * load-balance operations. | |
1586 | */ | |
1587 | static inline int throttled_lb_pair(struct task_group *tg, | |
1588 | int src_cpu, int dest_cpu) | |
1589 | { | |
1590 | struct cfs_rq *src_cfs_rq, *dest_cfs_rq; | |
1591 | ||
1592 | src_cfs_rq = tg->cfs_rq[src_cpu]; | |
1593 | dest_cfs_rq = tg->cfs_rq[dest_cpu]; | |
1594 | ||
1595 | return throttled_hierarchy(src_cfs_rq) || | |
1596 | throttled_hierarchy(dest_cfs_rq); | |
1597 | } | |
1598 | ||
1599 | /* updated child weight may affect parent so we have to do this bottom up */ | |
1600 | static int tg_unthrottle_up(struct task_group *tg, void *data) | |
1601 | { | |
1602 | struct rq *rq = data; | |
1603 | struct cfs_rq *cfs_rq = tg->cfs_rq[cpu_of(rq)]; | |
1604 | ||
1605 | cfs_rq->throttle_count--; | |
1606 | #ifdef CONFIG_SMP | |
1607 | if (!cfs_rq->throttle_count) { | |
1608 | u64 delta = rq->clock_task - cfs_rq->load_stamp; | |
1609 | ||
1610 | /* leaving throttled state, advance shares averaging windows */ | |
1611 | cfs_rq->load_stamp += delta; | |
1612 | cfs_rq->load_last += delta; | |
1613 | ||
1614 | /* update entity weight now that we are on_rq again */ | |
1615 | update_cfs_shares(cfs_rq); | |
1616 | } | |
1617 | #endif | |
1618 | ||
1619 | return 0; | |
1620 | } | |
1621 | ||
1622 | static int tg_throttle_down(struct task_group *tg, void *data) | |
1623 | { | |
1624 | struct rq *rq = data; | |
1625 | struct cfs_rq *cfs_rq = tg->cfs_rq[cpu_of(rq)]; | |
1626 | ||
1627 | /* group is entering throttled state, record last load */ | |
1628 | if (!cfs_rq->throttle_count) | |
1629 | update_cfs_load(cfs_rq, 0); | |
1630 | cfs_rq->throttle_count++; | |
1631 | ||
1632 | return 0; | |
1633 | } | |
1634 | ||
d3d9dc33 | 1635 | static void throttle_cfs_rq(struct cfs_rq *cfs_rq) |
85dac906 PT |
1636 | { |
1637 | struct rq *rq = rq_of(cfs_rq); | |
1638 | struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg); | |
1639 | struct sched_entity *se; | |
1640 | long task_delta, dequeue = 1; | |
1641 | ||
1642 | se = cfs_rq->tg->se[cpu_of(rq_of(cfs_rq))]; | |
1643 | ||
1644 | /* account load preceding throttle */ | |
64660c86 PT |
1645 | rcu_read_lock(); |
1646 | walk_tg_tree_from(cfs_rq->tg, tg_throttle_down, tg_nop, (void *)rq); | |
1647 | rcu_read_unlock(); | |
85dac906 PT |
1648 | |
1649 | task_delta = cfs_rq->h_nr_running; | |
1650 | for_each_sched_entity(se) { | |
1651 | struct cfs_rq *qcfs_rq = cfs_rq_of(se); | |
1652 | /* throttled entity or throttle-on-deactivate */ | |
1653 | if (!se->on_rq) | |
1654 | break; | |
1655 | ||
1656 | if (dequeue) | |
1657 | dequeue_entity(qcfs_rq, se, DEQUEUE_SLEEP); | |
1658 | qcfs_rq->h_nr_running -= task_delta; | |
1659 | ||
1660 | if (qcfs_rq->load.weight) | |
1661 | dequeue = 0; | |
1662 | } | |
1663 | ||
1664 | if (!se) | |
1665 | rq->nr_running -= task_delta; | |
1666 | ||
1667 | cfs_rq->throttled = 1; | |
e8da1b18 | 1668 | cfs_rq->throttled_timestamp = rq->clock; |
85dac906 PT |
1669 | raw_spin_lock(&cfs_b->lock); |
1670 | list_add_tail_rcu(&cfs_rq->throttled_list, &cfs_b->throttled_cfs_rq); | |
1671 | raw_spin_unlock(&cfs_b->lock); | |
1672 | } | |
1673 | ||
029632fb | 1674 | void unthrottle_cfs_rq(struct cfs_rq *cfs_rq) |
671fd9da PT |
1675 | { |
1676 | struct rq *rq = rq_of(cfs_rq); | |
1677 | struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg); | |
1678 | struct sched_entity *se; | |
1679 | int enqueue = 1; | |
1680 | long task_delta; | |
1681 | ||
1682 | se = cfs_rq->tg->se[cpu_of(rq_of(cfs_rq))]; | |
1683 | ||
1684 | cfs_rq->throttled = 0; | |
1685 | raw_spin_lock(&cfs_b->lock); | |
e8da1b18 | 1686 | cfs_b->throttled_time += rq->clock - cfs_rq->throttled_timestamp; |
671fd9da PT |
1687 | list_del_rcu(&cfs_rq->throttled_list); |
1688 | raw_spin_unlock(&cfs_b->lock); | |
e8da1b18 | 1689 | cfs_rq->throttled_timestamp = 0; |
671fd9da | 1690 | |
64660c86 PT |
1691 | update_rq_clock(rq); |
1692 | /* update hierarchical throttle state */ | |
1693 | walk_tg_tree_from(cfs_rq->tg, tg_nop, tg_unthrottle_up, (void *)rq); | |
1694 | ||
671fd9da PT |
1695 | if (!cfs_rq->load.weight) |
1696 | return; | |
1697 | ||
1698 | task_delta = cfs_rq->h_nr_running; | |
1699 | for_each_sched_entity(se) { | |
1700 | if (se->on_rq) | |
1701 | enqueue = 0; | |
1702 | ||
1703 | cfs_rq = cfs_rq_of(se); | |
1704 | if (enqueue) | |
1705 | enqueue_entity(cfs_rq, se, ENQUEUE_WAKEUP); | |
1706 | cfs_rq->h_nr_running += task_delta; | |
1707 | ||
1708 | if (cfs_rq_throttled(cfs_rq)) | |
1709 | break; | |
1710 | } | |
1711 | ||
1712 | if (!se) | |
1713 | rq->nr_running += task_delta; | |
1714 | ||
1715 | /* determine whether we need to wake up potentially idle cpu */ | |
1716 | if (rq->curr == rq->idle && rq->cfs.nr_running) | |
1717 | resched_task(rq->curr); | |
1718 | } | |
1719 | ||
1720 | static u64 distribute_cfs_runtime(struct cfs_bandwidth *cfs_b, | |
1721 | u64 remaining, u64 expires) | |
1722 | { | |
1723 | struct cfs_rq *cfs_rq; | |
1724 | u64 runtime = remaining; | |
1725 | ||
1726 | rcu_read_lock(); | |
1727 | list_for_each_entry_rcu(cfs_rq, &cfs_b->throttled_cfs_rq, | |
1728 | throttled_list) { | |
1729 | struct rq *rq = rq_of(cfs_rq); | |
1730 | ||
1731 | raw_spin_lock(&rq->lock); | |
1732 | if (!cfs_rq_throttled(cfs_rq)) | |
1733 | goto next; | |
1734 | ||
1735 | runtime = -cfs_rq->runtime_remaining + 1; | |
1736 | if (runtime > remaining) | |
1737 | runtime = remaining; | |
1738 | remaining -= runtime; | |
1739 | ||
1740 | cfs_rq->runtime_remaining += runtime; | |
1741 | cfs_rq->runtime_expires = expires; | |
1742 | ||
1743 | /* we check whether we're throttled above */ | |
1744 | if (cfs_rq->runtime_remaining > 0) | |
1745 | unthrottle_cfs_rq(cfs_rq); | |
1746 | ||
1747 | next: | |
1748 | raw_spin_unlock(&rq->lock); | |
1749 | ||
1750 | if (!remaining) | |
1751 | break; | |
1752 | } | |
1753 | rcu_read_unlock(); | |
1754 | ||
1755 | return remaining; | |
1756 | } | |
1757 | ||
58088ad0 PT |
1758 | /* |
1759 | * Responsible for refilling a task_group's bandwidth and unthrottling its | |
1760 | * cfs_rqs as appropriate. If there has been no activity within the last | |
1761 | * period the timer is deactivated until scheduling resumes; cfs_b->idle is | |
1762 | * used to track this state. | |
1763 | */ | |
1764 | static int do_sched_cfs_period_timer(struct cfs_bandwidth *cfs_b, int overrun) | |
1765 | { | |
671fd9da PT |
1766 | u64 runtime, runtime_expires; |
1767 | int idle = 1, throttled; | |
58088ad0 PT |
1768 | |
1769 | raw_spin_lock(&cfs_b->lock); | |
1770 | /* no need to continue the timer with no bandwidth constraint */ | |
1771 | if (cfs_b->quota == RUNTIME_INF) | |
1772 | goto out_unlock; | |
1773 | ||
671fd9da PT |
1774 | throttled = !list_empty(&cfs_b->throttled_cfs_rq); |
1775 | /* idle depends on !throttled (for the case of a large deficit) */ | |
1776 | idle = cfs_b->idle && !throttled; | |
e8da1b18 | 1777 | cfs_b->nr_periods += overrun; |
671fd9da | 1778 | |
a9cf55b2 PT |
1779 | /* if we're going inactive then everything else can be deferred */ |
1780 | if (idle) | |
1781 | goto out_unlock; | |
1782 | ||
1783 | __refill_cfs_bandwidth_runtime(cfs_b); | |
1784 | ||
671fd9da PT |
1785 | if (!throttled) { |
1786 | /* mark as potentially idle for the upcoming period */ | |
1787 | cfs_b->idle = 1; | |
1788 | goto out_unlock; | |
1789 | } | |
1790 | ||
e8da1b18 NR |
1791 | /* account preceding periods in which throttling occurred */ |
1792 | cfs_b->nr_throttled += overrun; | |
1793 | ||
671fd9da PT |
1794 | /* |
1795 | * There are throttled entities so we must first use the new bandwidth | |
1796 | * to unthrottle them before making it generally available. This | |
1797 | * ensures that all existing debts will be paid before a new cfs_rq is | |
1798 | * allowed to run. | |
1799 | */ | |
1800 | runtime = cfs_b->runtime; | |
1801 | runtime_expires = cfs_b->runtime_expires; | |
1802 | cfs_b->runtime = 0; | |
1803 | ||
1804 | /* | |
1805 | * This check is repeated as we are holding onto the new bandwidth | |
1806 | * while we unthrottle. This can potentially race with an unthrottled | |
1807 | * group trying to acquire new bandwidth from the global pool. | |
1808 | */ | |
1809 | while (throttled && runtime > 0) { | |
1810 | raw_spin_unlock(&cfs_b->lock); | |
1811 | /* we can't nest cfs_b->lock while distributing bandwidth */ | |
1812 | runtime = distribute_cfs_runtime(cfs_b, runtime, | |
1813 | runtime_expires); | |
1814 | raw_spin_lock(&cfs_b->lock); | |
1815 | ||
1816 | throttled = !list_empty(&cfs_b->throttled_cfs_rq); | |
1817 | } | |
58088ad0 | 1818 | |
671fd9da PT |
1819 | /* return (any) remaining runtime */ |
1820 | cfs_b->runtime = runtime; | |
1821 | /* | |
1822 | * While we are ensured activity in the period following an | |
1823 | * unthrottle, this also covers the case in which the new bandwidth is | |
1824 | * insufficient to cover the existing bandwidth deficit. (Forcing the | |
1825 | * timer to remain active while there are any throttled entities.) | |
1826 | */ | |
1827 | cfs_b->idle = 0; | |
58088ad0 PT |
1828 | out_unlock: |
1829 | if (idle) | |
1830 | cfs_b->timer_active = 0; | |
1831 | raw_spin_unlock(&cfs_b->lock); | |
1832 | ||
1833 | return idle; | |
1834 | } | |
d3d9dc33 | 1835 | |
d8b4986d PT |
1836 | /* a cfs_rq won't donate quota below this amount */ |
1837 | static const u64 min_cfs_rq_runtime = 1 * NSEC_PER_MSEC; | |
1838 | /* minimum remaining period time to redistribute slack quota */ | |
1839 | static const u64 min_bandwidth_expiration = 2 * NSEC_PER_MSEC; | |
1840 | /* how long we wait to gather additional slack before distributing */ | |
1841 | static const u64 cfs_bandwidth_slack_period = 5 * NSEC_PER_MSEC; | |
1842 | ||
1843 | /* are we near the end of the current quota period? */ | |
1844 | static int runtime_refresh_within(struct cfs_bandwidth *cfs_b, u64 min_expire) | |
1845 | { | |
1846 | struct hrtimer *refresh_timer = &cfs_b->period_timer; | |
1847 | u64 remaining; | |
1848 | ||
1849 | /* if the call-back is running a quota refresh is already occurring */ | |
1850 | if (hrtimer_callback_running(refresh_timer)) | |
1851 | return 1; | |
1852 | ||
1853 | /* is a quota refresh about to occur? */ | |
1854 | remaining = ktime_to_ns(hrtimer_expires_remaining(refresh_timer)); | |
1855 | if (remaining < min_expire) | |
1856 | return 1; | |
1857 | ||
1858 | return 0; | |
1859 | } | |
1860 | ||
1861 | static void start_cfs_slack_bandwidth(struct cfs_bandwidth *cfs_b) | |
1862 | { | |
1863 | u64 min_left = cfs_bandwidth_slack_period + min_bandwidth_expiration; | |
1864 | ||
1865 | /* if there's a quota refresh soon don't bother with slack */ | |
1866 | if (runtime_refresh_within(cfs_b, min_left)) | |
1867 | return; | |
1868 | ||
1869 | start_bandwidth_timer(&cfs_b->slack_timer, | |
1870 | ns_to_ktime(cfs_bandwidth_slack_period)); | |
1871 | } | |
1872 | ||
1873 | /* we know any runtime found here is valid as update_curr() precedes return */ | |
1874 | static void __return_cfs_rq_runtime(struct cfs_rq *cfs_rq) | |
1875 | { | |
1876 | struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg); | |
1877 | s64 slack_runtime = cfs_rq->runtime_remaining - min_cfs_rq_runtime; | |
1878 | ||
1879 | if (slack_runtime <= 0) | |
1880 | return; | |
1881 | ||
1882 | raw_spin_lock(&cfs_b->lock); | |
1883 | if (cfs_b->quota != RUNTIME_INF && | |
1884 | cfs_rq->runtime_expires == cfs_b->runtime_expires) { | |
1885 | cfs_b->runtime += slack_runtime; | |
1886 | ||
1887 | /* we are under rq->lock, defer unthrottling using a timer */ | |
1888 | if (cfs_b->runtime > sched_cfs_bandwidth_slice() && | |
1889 | !list_empty(&cfs_b->throttled_cfs_rq)) | |
1890 | start_cfs_slack_bandwidth(cfs_b); | |
1891 | } | |
1892 | raw_spin_unlock(&cfs_b->lock); | |
1893 | ||
1894 | /* even if it's not valid for return we don't want to try again */ | |
1895 | cfs_rq->runtime_remaining -= slack_runtime; | |
1896 | } | |
1897 | ||
1898 | static __always_inline void return_cfs_rq_runtime(struct cfs_rq *cfs_rq) | |
1899 | { | |
56f570e5 PT |
1900 | if (!cfs_bandwidth_used()) |
1901 | return; | |
1902 | ||
fccfdc6f | 1903 | if (!cfs_rq->runtime_enabled || cfs_rq->nr_running) |
d8b4986d PT |
1904 | return; |
1905 | ||
1906 | __return_cfs_rq_runtime(cfs_rq); | |
1907 | } | |
1908 | ||
1909 | /* | |
1910 | * This is done with a timer (instead of inline with bandwidth return) since | |
1911 | * it's necessary to juggle rq->locks to unthrottle their respective cfs_rqs. | |
1912 | */ | |
1913 | static void do_sched_cfs_slack_timer(struct cfs_bandwidth *cfs_b) | |
1914 | { | |
1915 | u64 runtime = 0, slice = sched_cfs_bandwidth_slice(); | |
1916 | u64 expires; | |
1917 | ||
1918 | /* confirm we're still not at a refresh boundary */ | |
1919 | if (runtime_refresh_within(cfs_b, min_bandwidth_expiration)) | |
1920 | return; | |
1921 | ||
1922 | raw_spin_lock(&cfs_b->lock); | |
1923 | if (cfs_b->quota != RUNTIME_INF && cfs_b->runtime > slice) { | |
1924 | runtime = cfs_b->runtime; | |
1925 | cfs_b->runtime = 0; | |
1926 | } | |
1927 | expires = cfs_b->runtime_expires; | |
1928 | raw_spin_unlock(&cfs_b->lock); | |
1929 | ||
1930 | if (!runtime) | |
1931 | return; | |
1932 | ||
1933 | runtime = distribute_cfs_runtime(cfs_b, runtime, expires); | |
1934 | ||
1935 | raw_spin_lock(&cfs_b->lock); | |
1936 | if (expires == cfs_b->runtime_expires) | |
1937 | cfs_b->runtime = runtime; | |
1938 | raw_spin_unlock(&cfs_b->lock); | |
1939 | } | |
1940 | ||
d3d9dc33 PT |
1941 | /* |
1942 | * When a group wakes up we want to make sure that its quota is not already | |
1943 | * expired/exceeded, otherwise it may be allowed to steal additional ticks of | |
1944 | * runtime as update_curr() throttling can not not trigger until it's on-rq. | |
1945 | */ | |
1946 | static void check_enqueue_throttle(struct cfs_rq *cfs_rq) | |
1947 | { | |
56f570e5 PT |
1948 | if (!cfs_bandwidth_used()) |
1949 | return; | |
1950 | ||
d3d9dc33 PT |
1951 | /* an active group must be handled by the update_curr()->put() path */ |
1952 | if (!cfs_rq->runtime_enabled || cfs_rq->curr) | |
1953 | return; | |
1954 | ||
1955 | /* ensure the group is not already throttled */ | |
1956 | if (cfs_rq_throttled(cfs_rq)) | |
1957 | return; | |
1958 | ||
1959 | /* update runtime allocation */ | |
1960 | account_cfs_rq_runtime(cfs_rq, 0); | |
1961 | if (cfs_rq->runtime_remaining <= 0) | |
1962 | throttle_cfs_rq(cfs_rq); | |
1963 | } | |
1964 | ||
1965 | /* conditionally throttle active cfs_rq's from put_prev_entity() */ | |
1966 | static void check_cfs_rq_runtime(struct cfs_rq *cfs_rq) | |
1967 | { | |
56f570e5 PT |
1968 | if (!cfs_bandwidth_used()) |
1969 | return; | |
1970 | ||
d3d9dc33 PT |
1971 | if (likely(!cfs_rq->runtime_enabled || cfs_rq->runtime_remaining > 0)) |
1972 | return; | |
1973 | ||
1974 | /* | |
1975 | * it's possible for a throttled entity to be forced into a running | |
1976 | * state (e.g. set_curr_task), in this case we're finished. | |
1977 | */ | |
1978 | if (cfs_rq_throttled(cfs_rq)) | |
1979 | return; | |
1980 | ||
1981 | throttle_cfs_rq(cfs_rq); | |
1982 | } | |
029632fb PZ |
1983 | |
1984 | static inline u64 default_cfs_period(void); | |
1985 | static int do_sched_cfs_period_timer(struct cfs_bandwidth *cfs_b, int overrun); | |
1986 | static void do_sched_cfs_slack_timer(struct cfs_bandwidth *cfs_b); | |
1987 | ||
1988 | static enum hrtimer_restart sched_cfs_slack_timer(struct hrtimer *timer) | |
1989 | { | |
1990 | struct cfs_bandwidth *cfs_b = | |
1991 | container_of(timer, struct cfs_bandwidth, slack_timer); | |
1992 | do_sched_cfs_slack_timer(cfs_b); | |
1993 | ||
1994 | return HRTIMER_NORESTART; | |
1995 | } | |
1996 | ||
1997 | static enum hrtimer_restart sched_cfs_period_timer(struct hrtimer *timer) | |
1998 | { | |
1999 | struct cfs_bandwidth *cfs_b = | |
2000 | container_of(timer, struct cfs_bandwidth, period_timer); | |
2001 | ktime_t now; | |
2002 | int overrun; | |
2003 | int idle = 0; | |
2004 | ||
2005 | for (;;) { | |
2006 | now = hrtimer_cb_get_time(timer); | |
2007 | overrun = hrtimer_forward(timer, now, cfs_b->period); | |
2008 | ||
2009 | if (!overrun) | |
2010 | break; | |
2011 | ||
2012 | idle = do_sched_cfs_period_timer(cfs_b, overrun); | |
2013 | } | |
2014 | ||
2015 | return idle ? HRTIMER_NORESTART : HRTIMER_RESTART; | |
2016 | } | |
2017 | ||
2018 | void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b) | |
2019 | { | |
2020 | raw_spin_lock_init(&cfs_b->lock); | |
2021 | cfs_b->runtime = 0; | |
2022 | cfs_b->quota = RUNTIME_INF; | |
2023 | cfs_b->period = ns_to_ktime(default_cfs_period()); | |
2024 | ||
2025 | INIT_LIST_HEAD(&cfs_b->throttled_cfs_rq); | |
2026 | hrtimer_init(&cfs_b->period_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); | |
2027 | cfs_b->period_timer.function = sched_cfs_period_timer; | |
2028 | hrtimer_init(&cfs_b->slack_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); | |
2029 | cfs_b->slack_timer.function = sched_cfs_slack_timer; | |
2030 | } | |
2031 | ||
2032 | static void init_cfs_rq_runtime(struct cfs_rq *cfs_rq) | |
2033 | { | |
2034 | cfs_rq->runtime_enabled = 0; | |
2035 | INIT_LIST_HEAD(&cfs_rq->throttled_list); | |
2036 | } | |
2037 | ||
2038 | /* requires cfs_b->lock, may release to reprogram timer */ | |
2039 | void __start_cfs_bandwidth(struct cfs_bandwidth *cfs_b) | |
2040 | { | |
2041 | /* | |
2042 | * The timer may be active because we're trying to set a new bandwidth | |
2043 | * period or because we're racing with the tear-down path | |
2044 | * (timer_active==0 becomes visible before the hrtimer call-back | |
2045 | * terminates). In either case we ensure that it's re-programmed | |
2046 | */ | |
2047 | while (unlikely(hrtimer_active(&cfs_b->period_timer))) { | |
2048 | raw_spin_unlock(&cfs_b->lock); | |
2049 | /* ensure cfs_b->lock is available while we wait */ | |
2050 | hrtimer_cancel(&cfs_b->period_timer); | |
2051 | ||
2052 | raw_spin_lock(&cfs_b->lock); | |
2053 | /* if someone else restarted the timer then we're done */ | |
2054 | if (cfs_b->timer_active) | |
2055 | return; | |
2056 | } | |
2057 | ||
2058 | cfs_b->timer_active = 1; | |
2059 | start_bandwidth_timer(&cfs_b->period_timer, cfs_b->period); | |
2060 | } | |
2061 | ||
2062 | static void destroy_cfs_bandwidth(struct cfs_bandwidth *cfs_b) | |
2063 | { | |
2064 | hrtimer_cancel(&cfs_b->period_timer); | |
2065 | hrtimer_cancel(&cfs_b->slack_timer); | |
2066 | } | |
2067 | ||
2068 | void unthrottle_offline_cfs_rqs(struct rq *rq) | |
2069 | { | |
2070 | struct cfs_rq *cfs_rq; | |
2071 | ||
2072 | for_each_leaf_cfs_rq(rq, cfs_rq) { | |
2073 | struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg); | |
2074 | ||
2075 | if (!cfs_rq->runtime_enabled) | |
2076 | continue; | |
2077 | ||
2078 | /* | |
2079 | * clock_task is not advancing so we just need to make sure | |
2080 | * there's some valid quota amount | |
2081 | */ | |
2082 | cfs_rq->runtime_remaining = cfs_b->quota; | |
2083 | if (cfs_rq_throttled(cfs_rq)) | |
2084 | unthrottle_cfs_rq(cfs_rq); | |
2085 | } | |
2086 | } | |
2087 | ||
2088 | #else /* CONFIG_CFS_BANDWIDTH */ | |
ec12cb7f PT |
2089 | static void account_cfs_rq_runtime(struct cfs_rq *cfs_rq, |
2090 | unsigned long delta_exec) {} | |
d3d9dc33 PT |
2091 | static void check_cfs_rq_runtime(struct cfs_rq *cfs_rq) {} |
2092 | static void check_enqueue_throttle(struct cfs_rq *cfs_rq) {} | |
d8b4986d | 2093 | static void return_cfs_rq_runtime(struct cfs_rq *cfs_rq) {} |
85dac906 PT |
2094 | |
2095 | static inline int cfs_rq_throttled(struct cfs_rq *cfs_rq) | |
2096 | { | |
2097 | return 0; | |
2098 | } | |
64660c86 PT |
2099 | |
2100 | static inline int throttled_hierarchy(struct cfs_rq *cfs_rq) | |
2101 | { | |
2102 | return 0; | |
2103 | } | |
2104 | ||
2105 | static inline int throttled_lb_pair(struct task_group *tg, | |
2106 | int src_cpu, int dest_cpu) | |
2107 | { | |
2108 | return 0; | |
2109 | } | |
029632fb PZ |
2110 | |
2111 | void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b) {} | |
2112 | ||
2113 | #ifdef CONFIG_FAIR_GROUP_SCHED | |
2114 | static void init_cfs_rq_runtime(struct cfs_rq *cfs_rq) {} | |
ab84d31e PT |
2115 | #endif |
2116 | ||
029632fb PZ |
2117 | static inline struct cfs_bandwidth *tg_cfs_bandwidth(struct task_group *tg) |
2118 | { | |
2119 | return NULL; | |
2120 | } | |
2121 | static inline void destroy_cfs_bandwidth(struct cfs_bandwidth *cfs_b) {} | |
2122 | void unthrottle_offline_cfs_rqs(struct rq *rq) {} | |
2123 | ||
2124 | #endif /* CONFIG_CFS_BANDWIDTH */ | |
2125 | ||
bf0f6f24 IM |
2126 | /************************************************** |
2127 | * CFS operations on tasks: | |
2128 | */ | |
2129 | ||
8f4d37ec PZ |
2130 | #ifdef CONFIG_SCHED_HRTICK |
2131 | static void hrtick_start_fair(struct rq *rq, struct task_struct *p) | |
2132 | { | |
8f4d37ec PZ |
2133 | struct sched_entity *se = &p->se; |
2134 | struct cfs_rq *cfs_rq = cfs_rq_of(se); | |
2135 | ||
2136 | WARN_ON(task_rq(p) != rq); | |
2137 | ||
2138 | if (hrtick_enabled(rq) && cfs_rq->nr_running > 1) { | |
2139 | u64 slice = sched_slice(cfs_rq, se); | |
2140 | u64 ran = se->sum_exec_runtime - se->prev_sum_exec_runtime; | |
2141 | s64 delta = slice - ran; | |
2142 | ||
2143 | if (delta < 0) { | |
2144 | if (rq->curr == p) | |
2145 | resched_task(p); | |
2146 | return; | |
2147 | } | |
2148 | ||
2149 | /* | |
2150 | * Don't schedule slices shorter than 10000ns, that just | |
2151 | * doesn't make sense. Rely on vruntime for fairness. | |
2152 | */ | |
31656519 | 2153 | if (rq->curr != p) |
157124c1 | 2154 | delta = max_t(s64, 10000LL, delta); |
8f4d37ec | 2155 | |
31656519 | 2156 | hrtick_start(rq, delta); |
8f4d37ec PZ |
2157 | } |
2158 | } | |
a4c2f00f PZ |
2159 | |
2160 | /* | |
2161 | * called from enqueue/dequeue and updates the hrtick when the | |
2162 | * current task is from our class and nr_running is low enough | |
2163 | * to matter. | |
2164 | */ | |
2165 | static void hrtick_update(struct rq *rq) | |
2166 | { | |
2167 | struct task_struct *curr = rq->curr; | |
2168 | ||
2169 | if (curr->sched_class != &fair_sched_class) | |
2170 | return; | |
2171 | ||
2172 | if (cfs_rq_of(&curr->se)->nr_running < sched_nr_latency) | |
2173 | hrtick_start_fair(rq, curr); | |
2174 | } | |
55e12e5e | 2175 | #else /* !CONFIG_SCHED_HRTICK */ |
8f4d37ec PZ |
2176 | static inline void |
2177 | hrtick_start_fair(struct rq *rq, struct task_struct *p) | |
2178 | { | |
2179 | } | |
a4c2f00f PZ |
2180 | |
2181 | static inline void hrtick_update(struct rq *rq) | |
2182 | { | |
2183 | } | |
8f4d37ec PZ |
2184 | #endif |
2185 | ||
bf0f6f24 IM |
2186 | /* |
2187 | * The enqueue_task method is called before nr_running is | |
2188 | * increased. Here we update the fair scheduling stats and | |
2189 | * then put the task into the rbtree: | |
2190 | */ | |
ea87bb78 | 2191 | static void |
371fd7e7 | 2192 | enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags) |
bf0f6f24 IM |
2193 | { |
2194 | struct cfs_rq *cfs_rq; | |
62fb1851 | 2195 | struct sched_entity *se = &p->se; |
bf0f6f24 IM |
2196 | |
2197 | for_each_sched_entity(se) { | |
62fb1851 | 2198 | if (se->on_rq) |
bf0f6f24 IM |
2199 | break; |
2200 | cfs_rq = cfs_rq_of(se); | |
88ec22d3 | 2201 | enqueue_entity(cfs_rq, se, flags); |
85dac906 PT |
2202 | |
2203 | /* | |
2204 | * end evaluation on encountering a throttled cfs_rq | |
2205 | * | |
2206 | * note: in the case of encountering a throttled cfs_rq we will | |
2207 | * post the final h_nr_running increment below. | |
2208 | */ | |
2209 | if (cfs_rq_throttled(cfs_rq)) | |
2210 | break; | |
953bfcd1 | 2211 | cfs_rq->h_nr_running++; |
85dac906 | 2212 | |
88ec22d3 | 2213 | flags = ENQUEUE_WAKEUP; |
bf0f6f24 | 2214 | } |
8f4d37ec | 2215 | |
2069dd75 | 2216 | for_each_sched_entity(se) { |
0f317143 | 2217 | cfs_rq = cfs_rq_of(se); |
953bfcd1 | 2218 | cfs_rq->h_nr_running++; |
2069dd75 | 2219 | |
85dac906 PT |
2220 | if (cfs_rq_throttled(cfs_rq)) |
2221 | break; | |
2222 | ||
d6b55918 | 2223 | update_cfs_load(cfs_rq, 0); |
6d5ab293 | 2224 | update_cfs_shares(cfs_rq); |
2069dd75 PZ |
2225 | } |
2226 | ||
85dac906 PT |
2227 | if (!se) |
2228 | inc_nr_running(rq); | |
a4c2f00f | 2229 | hrtick_update(rq); |
bf0f6f24 IM |
2230 | } |
2231 | ||
2f36825b VP |
2232 | static void set_next_buddy(struct sched_entity *se); |
2233 | ||
bf0f6f24 IM |
2234 | /* |
2235 | * The dequeue_task method is called before nr_running is | |
2236 | * decreased. We remove the task from the rbtree and | |
2237 | * update the fair scheduling stats: | |
2238 | */ | |
371fd7e7 | 2239 | static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags) |
bf0f6f24 IM |
2240 | { |
2241 | struct cfs_rq *cfs_rq; | |
62fb1851 | 2242 | struct sched_entity *se = &p->se; |
2f36825b | 2243 | int task_sleep = flags & DEQUEUE_SLEEP; |
bf0f6f24 IM |
2244 | |
2245 | for_each_sched_entity(se) { | |
2246 | cfs_rq = cfs_rq_of(se); | |
371fd7e7 | 2247 | dequeue_entity(cfs_rq, se, flags); |
85dac906 PT |
2248 | |
2249 | /* | |
2250 | * end evaluation on encountering a throttled cfs_rq | |
2251 | * | |
2252 | * note: in the case of encountering a throttled cfs_rq we will | |
2253 | * post the final h_nr_running decrement below. | |
2254 | */ | |
2255 | if (cfs_rq_throttled(cfs_rq)) | |
2256 | break; | |
953bfcd1 | 2257 | cfs_rq->h_nr_running--; |
2069dd75 | 2258 | |
bf0f6f24 | 2259 | /* Don't dequeue parent if it has other entities besides us */ |
2f36825b VP |
2260 | if (cfs_rq->load.weight) { |
2261 | /* | |
2262 | * Bias pick_next to pick a task from this cfs_rq, as | |
2263 | * p is sleeping when it is within its sched_slice. | |
2264 | */ | |
2265 | if (task_sleep && parent_entity(se)) | |
2266 | set_next_buddy(parent_entity(se)); | |
9598c82d PT |
2267 | |
2268 | /* avoid re-evaluating load for this entity */ | |
2269 | se = parent_entity(se); | |
bf0f6f24 | 2270 | break; |
2f36825b | 2271 | } |
371fd7e7 | 2272 | flags |= DEQUEUE_SLEEP; |
bf0f6f24 | 2273 | } |
8f4d37ec | 2274 | |
2069dd75 | 2275 | for_each_sched_entity(se) { |
0f317143 | 2276 | cfs_rq = cfs_rq_of(se); |
953bfcd1 | 2277 | cfs_rq->h_nr_running--; |
2069dd75 | 2278 | |
85dac906 PT |
2279 | if (cfs_rq_throttled(cfs_rq)) |
2280 | break; | |
2281 | ||
d6b55918 | 2282 | update_cfs_load(cfs_rq, 0); |
6d5ab293 | 2283 | update_cfs_shares(cfs_rq); |
2069dd75 PZ |
2284 | } |
2285 | ||
85dac906 PT |
2286 | if (!se) |
2287 | dec_nr_running(rq); | |
a4c2f00f | 2288 | hrtick_update(rq); |
bf0f6f24 IM |
2289 | } |
2290 | ||
e7693a36 | 2291 | #ifdef CONFIG_SMP |
029632fb PZ |
2292 | /* Used instead of source_load when we know the type == 0 */ |
2293 | static unsigned long weighted_cpuload(const int cpu) | |
2294 | { | |
2295 | return cpu_rq(cpu)->load.weight; | |
2296 | } | |
2297 | ||
2298 | /* | |
2299 | * Return a low guess at the load of a migration-source cpu weighted | |
2300 | * according to the scheduling class and "nice" value. | |
2301 | * | |
2302 | * We want to under-estimate the load of migration sources, to | |
2303 | * balance conservatively. | |
2304 | */ | |
2305 | static unsigned long source_load(int cpu, int type) | |
2306 | { | |
2307 | struct rq *rq = cpu_rq(cpu); | |
2308 | unsigned long total = weighted_cpuload(cpu); | |
2309 | ||
2310 | if (type == 0 || !sched_feat(LB_BIAS)) | |
2311 | return total; | |
2312 | ||
2313 | return min(rq->cpu_load[type-1], total); | |
2314 | } | |
2315 | ||
2316 | /* | |
2317 | * Return a high guess at the load of a migration-target cpu weighted | |
2318 | * according to the scheduling class and "nice" value. | |
2319 | */ | |
2320 | static unsigned long target_load(int cpu, int type) | |
2321 | { | |
2322 | struct rq *rq = cpu_rq(cpu); | |
2323 | unsigned long total = weighted_cpuload(cpu); | |
2324 | ||
2325 | if (type == 0 || !sched_feat(LB_BIAS)) | |
2326 | return total; | |
2327 | ||
2328 | return max(rq->cpu_load[type-1], total); | |
2329 | } | |
2330 | ||
2331 | static unsigned long power_of(int cpu) | |
2332 | { | |
2333 | return cpu_rq(cpu)->cpu_power; | |
2334 | } | |
2335 | ||
2336 | static unsigned long cpu_avg_load_per_task(int cpu) | |
2337 | { | |
2338 | struct rq *rq = cpu_rq(cpu); | |
2339 | unsigned long nr_running = ACCESS_ONCE(rq->nr_running); | |
2340 | ||
2341 | if (nr_running) | |
2342 | return rq->load.weight / nr_running; | |
2343 | ||
2344 | return 0; | |
2345 | } | |
2346 | ||
098fb9db | 2347 | |
74f8e4b2 | 2348 | static void task_waking_fair(struct task_struct *p) |
88ec22d3 PZ |
2349 | { |
2350 | struct sched_entity *se = &p->se; | |
2351 | struct cfs_rq *cfs_rq = cfs_rq_of(se); | |
3fe1698b PZ |
2352 | u64 min_vruntime; |
2353 | ||
2354 | #ifndef CONFIG_64BIT | |
2355 | u64 min_vruntime_copy; | |
88ec22d3 | 2356 | |
3fe1698b PZ |
2357 | do { |
2358 | min_vruntime_copy = cfs_rq->min_vruntime_copy; | |
2359 | smp_rmb(); | |
2360 | min_vruntime = cfs_rq->min_vruntime; | |
2361 | } while (min_vruntime != min_vruntime_copy); | |
2362 | #else | |
2363 | min_vruntime = cfs_rq->min_vruntime; | |
2364 | #endif | |
88ec22d3 | 2365 | |
3fe1698b | 2366 | se->vruntime -= min_vruntime; |
88ec22d3 PZ |
2367 | } |
2368 | ||
bb3469ac | 2369 | #ifdef CONFIG_FAIR_GROUP_SCHED |
f5bfb7d9 PZ |
2370 | /* |
2371 | * effective_load() calculates the load change as seen from the root_task_group | |
2372 | * | |
2373 | * Adding load to a group doesn't make a group heavier, but can cause movement | |
2374 | * of group shares between cpus. Assuming the shares were perfectly aligned one | |
2375 | * can calculate the shift in shares. | |
cf5f0acf PZ |
2376 | * |
2377 | * Calculate the effective load difference if @wl is added (subtracted) to @tg | |
2378 | * on this @cpu and results in a total addition (subtraction) of @wg to the | |
2379 | * total group weight. | |
2380 | * | |
2381 | * Given a runqueue weight distribution (rw_i) we can compute a shares | |
2382 | * distribution (s_i) using: | |
2383 | * | |
2384 | * s_i = rw_i / \Sum rw_j (1) | |
2385 | * | |
2386 | * Suppose we have 4 CPUs and our @tg is a direct child of the root group and | |
2387 | * has 7 equal weight tasks, distributed as below (rw_i), with the resulting | |
2388 | * shares distribution (s_i): | |
2389 | * | |
2390 | * rw_i = { 2, 4, 1, 0 } | |
2391 | * s_i = { 2/7, 4/7, 1/7, 0 } | |
2392 | * | |
2393 | * As per wake_affine() we're interested in the load of two CPUs (the CPU the | |
2394 | * task used to run on and the CPU the waker is running on), we need to | |
2395 | * compute the effect of waking a task on either CPU and, in case of a sync | |
2396 | * wakeup, compute the effect of the current task going to sleep. | |
2397 | * | |
2398 | * So for a change of @wl to the local @cpu with an overall group weight change | |
2399 | * of @wl we can compute the new shares distribution (s'_i) using: | |
2400 | * | |
2401 | * s'_i = (rw_i + @wl) / (@wg + \Sum rw_j) (2) | |
2402 | * | |
2403 | * Suppose we're interested in CPUs 0 and 1, and want to compute the load | |
2404 | * differences in waking a task to CPU 0. The additional task changes the | |
2405 | * weight and shares distributions like: | |
2406 | * | |
2407 | * rw'_i = { 3, 4, 1, 0 } | |
2408 | * s'_i = { 3/8, 4/8, 1/8, 0 } | |
2409 | * | |
2410 | * We can then compute the difference in effective weight by using: | |
2411 | * | |
2412 | * dw_i = S * (s'_i - s_i) (3) | |
2413 | * | |
2414 | * Where 'S' is the group weight as seen by its parent. | |
2415 | * | |
2416 | * Therefore the effective change in loads on CPU 0 would be 5/56 (3/8 - 2/7) | |
2417 | * times the weight of the group. The effect on CPU 1 would be -4/56 (4/8 - | |
2418 | * 4/7) times the weight of the group. | |
f5bfb7d9 | 2419 | */ |
2069dd75 | 2420 | static long effective_load(struct task_group *tg, int cpu, long wl, long wg) |
bb3469ac | 2421 | { |
4be9daaa | 2422 | struct sched_entity *se = tg->se[cpu]; |
f1d239f7 | 2423 | |
cf5f0acf | 2424 | if (!tg->parent) /* the trivial, non-cgroup case */ |
f1d239f7 PZ |
2425 | return wl; |
2426 | ||
4be9daaa | 2427 | for_each_sched_entity(se) { |
cf5f0acf | 2428 | long w, W; |
4be9daaa | 2429 | |
977dda7c | 2430 | tg = se->my_q->tg; |
bb3469ac | 2431 | |
cf5f0acf PZ |
2432 | /* |
2433 | * W = @wg + \Sum rw_j | |
2434 | */ | |
2435 | W = wg + calc_tg_weight(tg, se->my_q); | |
4be9daaa | 2436 | |
cf5f0acf PZ |
2437 | /* |
2438 | * w = rw_i + @wl | |
2439 | */ | |
2440 | w = se->my_q->load.weight + wl; | |
940959e9 | 2441 | |
cf5f0acf PZ |
2442 | /* |
2443 | * wl = S * s'_i; see (2) | |
2444 | */ | |
2445 | if (W > 0 && w < W) | |
2446 | wl = (w * tg->shares) / W; | |
977dda7c PT |
2447 | else |
2448 | wl = tg->shares; | |
940959e9 | 2449 | |
cf5f0acf PZ |
2450 | /* |
2451 | * Per the above, wl is the new se->load.weight value; since | |
2452 | * those are clipped to [MIN_SHARES, ...) do so now. See | |
2453 | * calc_cfs_shares(). | |
2454 | */ | |
977dda7c PT |
2455 | if (wl < MIN_SHARES) |
2456 | wl = MIN_SHARES; | |
cf5f0acf PZ |
2457 | |
2458 | /* | |
2459 | * wl = dw_i = S * (s'_i - s_i); see (3) | |
2460 | */ | |
977dda7c | 2461 | wl -= se->load.weight; |
cf5f0acf PZ |
2462 | |
2463 | /* | |
2464 | * Recursively apply this logic to all parent groups to compute | |
2465 | * the final effective load change on the root group. Since | |
2466 | * only the @tg group gets extra weight, all parent groups can | |
2467 | * only redistribute existing shares. @wl is the shift in shares | |
2468 | * resulting from this level per the above. | |
2469 | */ | |
4be9daaa | 2470 | wg = 0; |
4be9daaa | 2471 | } |
bb3469ac | 2472 | |
4be9daaa | 2473 | return wl; |
bb3469ac PZ |
2474 | } |
2475 | #else | |
4be9daaa | 2476 | |
83378269 PZ |
2477 | static inline unsigned long effective_load(struct task_group *tg, int cpu, |
2478 | unsigned long wl, unsigned long wg) | |
4be9daaa | 2479 | { |
83378269 | 2480 | return wl; |
bb3469ac | 2481 | } |
4be9daaa | 2482 | |
bb3469ac PZ |
2483 | #endif |
2484 | ||
c88d5910 | 2485 | static int wake_affine(struct sched_domain *sd, struct task_struct *p, int sync) |
098fb9db | 2486 | { |
e37b6a7b | 2487 | s64 this_load, load; |
c88d5910 | 2488 | int idx, this_cpu, prev_cpu; |
098fb9db | 2489 | unsigned long tl_per_task; |
c88d5910 | 2490 | struct task_group *tg; |
83378269 | 2491 | unsigned long weight; |
b3137bc8 | 2492 | int balanced; |
098fb9db | 2493 | |
c88d5910 PZ |
2494 | idx = sd->wake_idx; |
2495 | this_cpu = smp_processor_id(); | |
2496 | prev_cpu = task_cpu(p); | |
2497 | load = source_load(prev_cpu, idx); | |
2498 | this_load = target_load(this_cpu, idx); | |
098fb9db | 2499 | |
b3137bc8 MG |
2500 | /* |
2501 | * If sync wakeup then subtract the (maximum possible) | |
2502 | * effect of the currently running task from the load | |
2503 | * of the current CPU: | |
2504 | */ | |
83378269 PZ |
2505 | if (sync) { |
2506 | tg = task_group(current); | |
2507 | weight = current->se.load.weight; | |
2508 | ||
c88d5910 | 2509 | this_load += effective_load(tg, this_cpu, -weight, -weight); |
83378269 PZ |
2510 | load += effective_load(tg, prev_cpu, 0, -weight); |
2511 | } | |
b3137bc8 | 2512 | |
83378269 PZ |
2513 | tg = task_group(p); |
2514 | weight = p->se.load.weight; | |
b3137bc8 | 2515 | |
71a29aa7 PZ |
2516 | /* |
2517 | * In low-load situations, where prev_cpu is idle and this_cpu is idle | |
c88d5910 PZ |
2518 | * due to the sync cause above having dropped this_load to 0, we'll |
2519 | * always have an imbalance, but there's really nothing you can do | |
2520 | * about that, so that's good too. | |
71a29aa7 PZ |
2521 | * |
2522 | * Otherwise check if either cpus are near enough in load to allow this | |
2523 | * task to be woken on this_cpu. | |
2524 | */ | |
e37b6a7b PT |
2525 | if (this_load > 0) { |
2526 | s64 this_eff_load, prev_eff_load; | |
e51fd5e2 PZ |
2527 | |
2528 | this_eff_load = 100; | |
2529 | this_eff_load *= power_of(prev_cpu); | |
2530 | this_eff_load *= this_load + | |
2531 | effective_load(tg, this_cpu, weight, weight); | |
2532 | ||
2533 | prev_eff_load = 100 + (sd->imbalance_pct - 100) / 2; | |
2534 | prev_eff_load *= power_of(this_cpu); | |
2535 | prev_eff_load *= load + effective_load(tg, prev_cpu, 0, weight); | |
2536 | ||
2537 | balanced = this_eff_load <= prev_eff_load; | |
2538 | } else | |
2539 | balanced = true; | |
b3137bc8 | 2540 | |
098fb9db | 2541 | /* |
4ae7d5ce IM |
2542 | * If the currently running task will sleep within |
2543 | * a reasonable amount of time then attract this newly | |
2544 | * woken task: | |
098fb9db | 2545 | */ |
2fb7635c PZ |
2546 | if (sync && balanced) |
2547 | return 1; | |
098fb9db | 2548 | |
41acab88 | 2549 | schedstat_inc(p, se.statistics.nr_wakeups_affine_attempts); |
098fb9db IM |
2550 | tl_per_task = cpu_avg_load_per_task(this_cpu); |
2551 | ||
c88d5910 PZ |
2552 | if (balanced || |
2553 | (this_load <= load && | |
2554 | this_load + target_load(prev_cpu, idx) <= tl_per_task)) { | |
098fb9db IM |
2555 | /* |
2556 | * This domain has SD_WAKE_AFFINE and | |
2557 | * p is cache cold in this domain, and | |
2558 | * there is no bad imbalance. | |
2559 | */ | |
c88d5910 | 2560 | schedstat_inc(sd, ttwu_move_affine); |
41acab88 | 2561 | schedstat_inc(p, se.statistics.nr_wakeups_affine); |
098fb9db IM |
2562 | |
2563 | return 1; | |
2564 | } | |
2565 | return 0; | |
2566 | } | |
2567 | ||
aaee1203 PZ |
2568 | /* |
2569 | * find_idlest_group finds and returns the least busy CPU group within the | |
2570 | * domain. | |
2571 | */ | |
2572 | static struct sched_group * | |
78e7ed53 | 2573 | find_idlest_group(struct sched_domain *sd, struct task_struct *p, |
5158f4e4 | 2574 | int this_cpu, int load_idx) |
e7693a36 | 2575 | { |
b3bd3de6 | 2576 | struct sched_group *idlest = NULL, *group = sd->groups; |
aaee1203 | 2577 | unsigned long min_load = ULONG_MAX, this_load = 0; |
aaee1203 | 2578 | int imbalance = 100 + (sd->imbalance_pct-100)/2; |
e7693a36 | 2579 | |
aaee1203 PZ |
2580 | do { |
2581 | unsigned long load, avg_load; | |
2582 | int local_group; | |
2583 | int i; | |
e7693a36 | 2584 | |
aaee1203 PZ |
2585 | /* Skip over this group if it has no CPUs allowed */ |
2586 | if (!cpumask_intersects(sched_group_cpus(group), | |
fa17b507 | 2587 | tsk_cpus_allowed(p))) |
aaee1203 PZ |
2588 | continue; |
2589 | ||
2590 | local_group = cpumask_test_cpu(this_cpu, | |
2591 | sched_group_cpus(group)); | |
2592 | ||
2593 | /* Tally up the load of all CPUs in the group */ | |
2594 | avg_load = 0; | |
2595 | ||
2596 | for_each_cpu(i, sched_group_cpus(group)) { | |
2597 | /* Bias balancing toward cpus of our domain */ | |
2598 | if (local_group) | |
2599 | load = source_load(i, load_idx); | |
2600 | else | |
2601 | load = target_load(i, load_idx); | |
2602 | ||
2603 | avg_load += load; | |
2604 | } | |
2605 | ||
2606 | /* Adjust by relative CPU power of the group */ | |
9c3f75cb | 2607 | avg_load = (avg_load * SCHED_POWER_SCALE) / group->sgp->power; |
aaee1203 PZ |
2608 | |
2609 | if (local_group) { | |
2610 | this_load = avg_load; | |
aaee1203 PZ |
2611 | } else if (avg_load < min_load) { |
2612 | min_load = avg_load; | |
2613 | idlest = group; | |
2614 | } | |
2615 | } while (group = group->next, group != sd->groups); | |
2616 | ||
2617 | if (!idlest || 100*this_load < imbalance*min_load) | |
2618 | return NULL; | |
2619 | return idlest; | |
2620 | } | |
2621 | ||
2622 | /* | |
2623 | * find_idlest_cpu - find the idlest cpu among the cpus in group. | |
2624 | */ | |
2625 | static int | |
2626 | find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu) | |
2627 | { | |
2628 | unsigned long load, min_load = ULONG_MAX; | |
2629 | int idlest = -1; | |
2630 | int i; | |
2631 | ||
2632 | /* Traverse only the allowed CPUs */ | |
fa17b507 | 2633 | for_each_cpu_and(i, sched_group_cpus(group), tsk_cpus_allowed(p)) { |
aaee1203 PZ |
2634 | load = weighted_cpuload(i); |
2635 | ||
2636 | if (load < min_load || (load == min_load && i == this_cpu)) { | |
2637 | min_load = load; | |
2638 | idlest = i; | |
e7693a36 GH |
2639 | } |
2640 | } | |
2641 | ||
aaee1203 PZ |
2642 | return idlest; |
2643 | } | |
e7693a36 | 2644 | |
a50bde51 PZ |
2645 | /* |
2646 | * Try and locate an idle CPU in the sched_domain. | |
2647 | */ | |
99bd5e2f | 2648 | static int select_idle_sibling(struct task_struct *p, int target) |
a50bde51 PZ |
2649 | { |
2650 | int cpu = smp_processor_id(); | |
2651 | int prev_cpu = task_cpu(p); | |
99bd5e2f | 2652 | struct sched_domain *sd; |
4dcfe102 PZ |
2653 | struct sched_group *sg; |
2654 | int i, smt = 0; | |
a50bde51 PZ |
2655 | |
2656 | /* | |
99bd5e2f SS |
2657 | * If the task is going to be woken-up on this cpu and if it is |
2658 | * already idle, then it is the right target. | |
a50bde51 | 2659 | */ |
99bd5e2f SS |
2660 | if (target == cpu && idle_cpu(cpu)) |
2661 | return cpu; | |
2662 | ||
2663 | /* | |
2664 | * If the task is going to be woken-up on the cpu where it previously | |
2665 | * ran and if it is currently idle, then it the right target. | |
2666 | */ | |
2667 | if (target == prev_cpu && idle_cpu(prev_cpu)) | |
fe3bcfe1 | 2668 | return prev_cpu; |
a50bde51 PZ |
2669 | |
2670 | /* | |
99bd5e2f | 2671 | * Otherwise, iterate the domains and find an elegible idle cpu. |
a50bde51 | 2672 | */ |
dce840a0 | 2673 | rcu_read_lock(); |
4dcfe102 | 2674 | again: |
99bd5e2f | 2675 | for_each_domain(target, sd) { |
4dcfe102 PZ |
2676 | if (!smt && (sd->flags & SD_SHARE_CPUPOWER)) |
2677 | continue; | |
99bd5e2f | 2678 | |
4dcfe102 PZ |
2679 | if (!(sd->flags & SD_SHARE_PKG_RESOURCES)) { |
2680 | if (!smt) { | |
2681 | smt = 1; | |
2682 | goto again; | |
99bd5e2f | 2683 | } |
4dcfe102 | 2684 | break; |
a50bde51 | 2685 | } |
99bd5e2f | 2686 | |
4dcfe102 PZ |
2687 | sg = sd->groups; |
2688 | do { | |
2689 | if (!cpumask_intersects(sched_group_cpus(sg), | |
2690 | tsk_cpus_allowed(p))) | |
2691 | goto next; | |
2692 | ||
2693 | for_each_cpu(i, sched_group_cpus(sg)) { | |
2694 | if (!idle_cpu(i)) | |
2695 | goto next; | |
2696 | } | |
2697 | ||
2698 | target = cpumask_first_and(sched_group_cpus(sg), | |
2699 | tsk_cpus_allowed(p)); | |
2700 | goto done; | |
2701 | next: | |
2702 | sg = sg->next; | |
2703 | } while (sg != sd->groups); | |
a50bde51 | 2704 | } |
4dcfe102 | 2705 | done: |
dce840a0 | 2706 | rcu_read_unlock(); |
a50bde51 PZ |
2707 | |
2708 | return target; | |
2709 | } | |
2710 | ||
aaee1203 PZ |
2711 | /* |
2712 | * sched_balance_self: balance the current task (running on cpu) in domains | |
2713 | * that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and | |
2714 | * SD_BALANCE_EXEC. | |
2715 | * | |
2716 | * Balance, ie. select the least loaded group. | |
2717 | * | |
2718 | * Returns the target CPU number, or the same CPU if no balancing is needed. | |
2719 | * | |
2720 | * preempt must be disabled. | |
2721 | */ | |
0017d735 | 2722 | static int |
7608dec2 | 2723 | select_task_rq_fair(struct task_struct *p, int sd_flag, int wake_flags) |
aaee1203 | 2724 | { |
29cd8bae | 2725 | struct sched_domain *tmp, *affine_sd = NULL, *sd = NULL; |
c88d5910 PZ |
2726 | int cpu = smp_processor_id(); |
2727 | int prev_cpu = task_cpu(p); | |
2728 | int new_cpu = cpu; | |
99bd5e2f | 2729 | int want_affine = 0; |
29cd8bae | 2730 | int want_sd = 1; |
5158f4e4 | 2731 | int sync = wake_flags & WF_SYNC; |
c88d5910 | 2732 | |
0763a660 | 2733 | if (sd_flag & SD_BALANCE_WAKE) { |
fa17b507 | 2734 | if (cpumask_test_cpu(cpu, tsk_cpus_allowed(p))) |
c88d5910 PZ |
2735 | want_affine = 1; |
2736 | new_cpu = prev_cpu; | |
2737 | } | |
aaee1203 | 2738 | |
dce840a0 | 2739 | rcu_read_lock(); |
aaee1203 | 2740 | for_each_domain(cpu, tmp) { |
e4f42888 PZ |
2741 | if (!(tmp->flags & SD_LOAD_BALANCE)) |
2742 | continue; | |
2743 | ||
aaee1203 | 2744 | /* |
ae154be1 PZ |
2745 | * If power savings logic is enabled for a domain, see if we |
2746 | * are not overloaded, if so, don't balance wider. | |
aaee1203 | 2747 | */ |
59abf026 | 2748 | if (tmp->flags & (SD_POWERSAVINGS_BALANCE|SD_PREFER_LOCAL)) { |
ae154be1 PZ |
2749 | unsigned long power = 0; |
2750 | unsigned long nr_running = 0; | |
2751 | unsigned long capacity; | |
2752 | int i; | |
2753 | ||
2754 | for_each_cpu(i, sched_domain_span(tmp)) { | |
2755 | power += power_of(i); | |
2756 | nr_running += cpu_rq(i)->cfs.nr_running; | |
2757 | } | |
2758 | ||
1399fa78 | 2759 | capacity = DIV_ROUND_CLOSEST(power, SCHED_POWER_SCALE); |
ae154be1 | 2760 | |
59abf026 PZ |
2761 | if (tmp->flags & SD_POWERSAVINGS_BALANCE) |
2762 | nr_running /= 2; | |
2763 | ||
2764 | if (nr_running < capacity) | |
29cd8bae | 2765 | want_sd = 0; |
ae154be1 | 2766 | } |
aaee1203 | 2767 | |
fe3bcfe1 | 2768 | /* |
99bd5e2f SS |
2769 | * If both cpu and prev_cpu are part of this domain, |
2770 | * cpu is a valid SD_WAKE_AFFINE target. | |
fe3bcfe1 | 2771 | */ |
99bd5e2f SS |
2772 | if (want_affine && (tmp->flags & SD_WAKE_AFFINE) && |
2773 | cpumask_test_cpu(prev_cpu, sched_domain_span(tmp))) { | |
2774 | affine_sd = tmp; | |
2775 | want_affine = 0; | |
c88d5910 PZ |
2776 | } |
2777 | ||
29cd8bae PZ |
2778 | if (!want_sd && !want_affine) |
2779 | break; | |
2780 | ||
0763a660 | 2781 | if (!(tmp->flags & sd_flag)) |
c88d5910 PZ |
2782 | continue; |
2783 | ||
29cd8bae PZ |
2784 | if (want_sd) |
2785 | sd = tmp; | |
2786 | } | |
2787 | ||
8b911acd | 2788 | if (affine_sd) { |
99bd5e2f | 2789 | if (cpu == prev_cpu || wake_affine(affine_sd, p, sync)) |
dce840a0 PZ |
2790 | prev_cpu = cpu; |
2791 | ||
2792 | new_cpu = select_idle_sibling(p, prev_cpu); | |
2793 | goto unlock; | |
8b911acd | 2794 | } |
e7693a36 | 2795 | |
aaee1203 | 2796 | while (sd) { |
5158f4e4 | 2797 | int load_idx = sd->forkexec_idx; |
aaee1203 | 2798 | struct sched_group *group; |
c88d5910 | 2799 | int weight; |
098fb9db | 2800 | |
0763a660 | 2801 | if (!(sd->flags & sd_flag)) { |
aaee1203 PZ |
2802 | sd = sd->child; |
2803 | continue; | |
2804 | } | |
098fb9db | 2805 | |
5158f4e4 PZ |
2806 | if (sd_flag & SD_BALANCE_WAKE) |
2807 | load_idx = sd->wake_idx; | |
098fb9db | 2808 | |
5158f4e4 | 2809 | group = find_idlest_group(sd, p, cpu, load_idx); |
aaee1203 PZ |
2810 | if (!group) { |
2811 | sd = sd->child; | |
2812 | continue; | |
2813 | } | |
4ae7d5ce | 2814 | |
d7c33c49 | 2815 | new_cpu = find_idlest_cpu(group, p, cpu); |
aaee1203 PZ |
2816 | if (new_cpu == -1 || new_cpu == cpu) { |
2817 | /* Now try balancing at a lower domain level of cpu */ | |
2818 | sd = sd->child; | |
2819 | continue; | |
e7693a36 | 2820 | } |
aaee1203 PZ |
2821 | |
2822 | /* Now try balancing at a lower domain level of new_cpu */ | |
2823 | cpu = new_cpu; | |
669c55e9 | 2824 | weight = sd->span_weight; |
aaee1203 PZ |
2825 | sd = NULL; |
2826 | for_each_domain(cpu, tmp) { | |
669c55e9 | 2827 | if (weight <= tmp->span_weight) |
aaee1203 | 2828 | break; |
0763a660 | 2829 | if (tmp->flags & sd_flag) |
aaee1203 PZ |
2830 | sd = tmp; |
2831 | } | |
2832 | /* while loop will break here if sd == NULL */ | |
e7693a36 | 2833 | } |
dce840a0 PZ |
2834 | unlock: |
2835 | rcu_read_unlock(); | |
e7693a36 | 2836 | |
c88d5910 | 2837 | return new_cpu; |
e7693a36 GH |
2838 | } |
2839 | #endif /* CONFIG_SMP */ | |
2840 | ||
e52fb7c0 PZ |
2841 | static unsigned long |
2842 | wakeup_gran(struct sched_entity *curr, struct sched_entity *se) | |
0bbd3336 PZ |
2843 | { |
2844 | unsigned long gran = sysctl_sched_wakeup_granularity; | |
2845 | ||
2846 | /* | |
e52fb7c0 PZ |
2847 | * Since its curr running now, convert the gran from real-time |
2848 | * to virtual-time in his units. | |
13814d42 MG |
2849 | * |
2850 | * By using 'se' instead of 'curr' we penalize light tasks, so | |
2851 | * they get preempted easier. That is, if 'se' < 'curr' then | |
2852 | * the resulting gran will be larger, therefore penalizing the | |
2853 | * lighter, if otoh 'se' > 'curr' then the resulting gran will | |
2854 | * be smaller, again penalizing the lighter task. | |
2855 | * | |
2856 | * This is especially important for buddies when the leftmost | |
2857 | * task is higher priority than the buddy. | |
0bbd3336 | 2858 | */ |
f4ad9bd2 | 2859 | return calc_delta_fair(gran, se); |
0bbd3336 PZ |
2860 | } |
2861 | ||
464b7527 PZ |
2862 | /* |
2863 | * Should 'se' preempt 'curr'. | |
2864 | * | |
2865 | * |s1 | |
2866 | * |s2 | |
2867 | * |s3 | |
2868 | * g | |
2869 | * |<--->|c | |
2870 | * | |
2871 | * w(c, s1) = -1 | |
2872 | * w(c, s2) = 0 | |
2873 | * w(c, s3) = 1 | |
2874 | * | |
2875 | */ | |
2876 | static int | |
2877 | wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se) | |
2878 | { | |
2879 | s64 gran, vdiff = curr->vruntime - se->vruntime; | |
2880 | ||
2881 | if (vdiff <= 0) | |
2882 | return -1; | |
2883 | ||
e52fb7c0 | 2884 | gran = wakeup_gran(curr, se); |
464b7527 PZ |
2885 | if (vdiff > gran) |
2886 | return 1; | |
2887 | ||
2888 | return 0; | |
2889 | } | |
2890 | ||
02479099 PZ |
2891 | static void set_last_buddy(struct sched_entity *se) |
2892 | { | |
69c80f3e VP |
2893 | if (entity_is_task(se) && unlikely(task_of(se)->policy == SCHED_IDLE)) |
2894 | return; | |
2895 | ||
2896 | for_each_sched_entity(se) | |
2897 | cfs_rq_of(se)->last = se; | |
02479099 PZ |
2898 | } |
2899 | ||
2900 | static void set_next_buddy(struct sched_entity *se) | |
2901 | { | |
69c80f3e VP |
2902 | if (entity_is_task(se) && unlikely(task_of(se)->policy == SCHED_IDLE)) |
2903 | return; | |
2904 | ||
2905 | for_each_sched_entity(se) | |
2906 | cfs_rq_of(se)->next = se; | |
02479099 PZ |
2907 | } |
2908 | ||
ac53db59 RR |
2909 | static void set_skip_buddy(struct sched_entity *se) |
2910 | { | |
69c80f3e VP |
2911 | for_each_sched_entity(se) |
2912 | cfs_rq_of(se)->skip = se; | |
ac53db59 RR |
2913 | } |
2914 | ||
bf0f6f24 IM |
2915 | /* |
2916 | * Preempt the current task with a newly woken task if needed: | |
2917 | */ | |
5a9b86f6 | 2918 | static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_flags) |
bf0f6f24 IM |
2919 | { |
2920 | struct task_struct *curr = rq->curr; | |
8651a86c | 2921 | struct sched_entity *se = &curr->se, *pse = &p->se; |
03e89e45 | 2922 | struct cfs_rq *cfs_rq = task_cfs_rq(curr); |
f685ceac | 2923 | int scale = cfs_rq->nr_running >= sched_nr_latency; |
2f36825b | 2924 | int next_buddy_marked = 0; |
bf0f6f24 | 2925 | |
4ae7d5ce IM |
2926 | if (unlikely(se == pse)) |
2927 | return; | |
2928 | ||
5238cdd3 PT |
2929 | /* |
2930 | * This is possible from callers such as pull_task(), in which we | |
2931 | * unconditionally check_prempt_curr() after an enqueue (which may have | |
2932 | * lead to a throttle). This both saves work and prevents false | |
2933 | * next-buddy nomination below. | |
2934 | */ | |
2935 | if (unlikely(throttled_hierarchy(cfs_rq_of(pse)))) | |
2936 | return; | |
2937 | ||
2f36825b | 2938 | if (sched_feat(NEXT_BUDDY) && scale && !(wake_flags & WF_FORK)) { |
3cb63d52 | 2939 | set_next_buddy(pse); |
2f36825b VP |
2940 | next_buddy_marked = 1; |
2941 | } | |
57fdc26d | 2942 | |
aec0a514 BR |
2943 | /* |
2944 | * We can come here with TIF_NEED_RESCHED already set from new task | |
2945 | * wake up path. | |
5238cdd3 PT |
2946 | * |
2947 | * Note: this also catches the edge-case of curr being in a throttled | |
2948 | * group (e.g. via set_curr_task), since update_curr() (in the | |
2949 | * enqueue of curr) will have resulted in resched being set. This | |
2950 | * prevents us from potentially nominating it as a false LAST_BUDDY | |
2951 | * below. | |
aec0a514 BR |
2952 | */ |
2953 | if (test_tsk_need_resched(curr)) | |
2954 | return; | |
2955 | ||
a2f5c9ab DH |
2956 | /* Idle tasks are by definition preempted by non-idle tasks. */ |
2957 | if (unlikely(curr->policy == SCHED_IDLE) && | |
2958 | likely(p->policy != SCHED_IDLE)) | |
2959 | goto preempt; | |
2960 | ||
91c234b4 | 2961 | /* |
a2f5c9ab DH |
2962 | * Batch and idle tasks do not preempt non-idle tasks (their preemption |
2963 | * is driven by the tick): | |
91c234b4 | 2964 | */ |
6bc912b7 | 2965 | if (unlikely(p->policy != SCHED_NORMAL)) |
91c234b4 | 2966 | return; |
bf0f6f24 | 2967 | |
464b7527 | 2968 | find_matching_se(&se, &pse); |
9bbd7374 | 2969 | update_curr(cfs_rq_of(se)); |
002f128b | 2970 | BUG_ON(!pse); |
2f36825b VP |
2971 | if (wakeup_preempt_entity(se, pse) == 1) { |
2972 | /* | |
2973 | * Bias pick_next to pick the sched entity that is | |
2974 | * triggering this preemption. | |
2975 | */ | |
2976 | if (!next_buddy_marked) | |
2977 | set_next_buddy(pse); | |
3a7e73a2 | 2978 | goto preempt; |
2f36825b | 2979 | } |
464b7527 | 2980 | |
3a7e73a2 | 2981 | return; |
a65ac745 | 2982 | |
3a7e73a2 PZ |
2983 | preempt: |
2984 | resched_task(curr); | |
2985 | /* | |
2986 | * Only set the backward buddy when the current task is still | |
2987 | * on the rq. This can happen when a wakeup gets interleaved | |
2988 | * with schedule on the ->pre_schedule() or idle_balance() | |
2989 | * point, either of which can * drop the rq lock. | |
2990 | * | |
2991 | * Also, during early boot the idle thread is in the fair class, | |
2992 | * for obvious reasons its a bad idea to schedule back to it. | |
2993 | */ | |
2994 | if (unlikely(!se->on_rq || curr == rq->idle)) | |
2995 | return; | |
2996 | ||
2997 | if (sched_feat(LAST_BUDDY) && scale && entity_is_task(se)) | |
2998 | set_last_buddy(se); | |
bf0f6f24 IM |
2999 | } |
3000 | ||
fb8d4724 | 3001 | static struct task_struct *pick_next_task_fair(struct rq *rq) |
bf0f6f24 | 3002 | { |
8f4d37ec | 3003 | struct task_struct *p; |
bf0f6f24 IM |
3004 | struct cfs_rq *cfs_rq = &rq->cfs; |
3005 | struct sched_entity *se; | |
3006 | ||
36ace27e | 3007 | if (!cfs_rq->nr_running) |
bf0f6f24 IM |
3008 | return NULL; |
3009 | ||
3010 | do { | |
9948f4b2 | 3011 | se = pick_next_entity(cfs_rq); |
f4b6755f | 3012 | set_next_entity(cfs_rq, se); |
bf0f6f24 IM |
3013 | cfs_rq = group_cfs_rq(se); |
3014 | } while (cfs_rq); | |
3015 | ||
8f4d37ec PZ |
3016 | p = task_of(se); |
3017 | hrtick_start_fair(rq, p); | |
3018 | ||
3019 | return p; | |
bf0f6f24 IM |
3020 | } |
3021 | ||
3022 | /* | |
3023 | * Account for a descheduled task: | |
3024 | */ | |
31ee529c | 3025 | static void put_prev_task_fair(struct rq *rq, struct task_struct *prev) |
bf0f6f24 IM |
3026 | { |
3027 | struct sched_entity *se = &prev->se; | |
3028 | struct cfs_rq *cfs_rq; | |
3029 | ||
3030 | for_each_sched_entity(se) { | |
3031 | cfs_rq = cfs_rq_of(se); | |
ab6cde26 | 3032 | put_prev_entity(cfs_rq, se); |
bf0f6f24 IM |
3033 | } |
3034 | } | |
3035 | ||
ac53db59 RR |
3036 | /* |
3037 | * sched_yield() is very simple | |
3038 | * | |
3039 | * The magic of dealing with the ->skip buddy is in pick_next_entity. | |
3040 | */ | |
3041 | static void yield_task_fair(struct rq *rq) | |
3042 | { | |
3043 | struct task_struct *curr = rq->curr; | |
3044 | struct cfs_rq *cfs_rq = task_cfs_rq(curr); | |
3045 | struct sched_entity *se = &curr->se; | |
3046 | ||
3047 | /* | |
3048 | * Are we the only task in the tree? | |
3049 | */ | |
3050 | if (unlikely(rq->nr_running == 1)) | |
3051 | return; | |
3052 | ||
3053 | clear_buddies(cfs_rq, se); | |
3054 | ||
3055 | if (curr->policy != SCHED_BATCH) { | |
3056 | update_rq_clock(rq); | |
3057 | /* | |
3058 | * Update run-time statistics of the 'current'. | |
3059 | */ | |
3060 | update_curr(cfs_rq); | |
3061 | } | |
3062 | ||
3063 | set_skip_buddy(se); | |
3064 | } | |
3065 | ||
d95f4122 MG |
3066 | static bool yield_to_task_fair(struct rq *rq, struct task_struct *p, bool preempt) |
3067 | { | |
3068 | struct sched_entity *se = &p->se; | |
3069 | ||
5238cdd3 PT |
3070 | /* throttled hierarchies are not runnable */ |
3071 | if (!se->on_rq || throttled_hierarchy(cfs_rq_of(se))) | |
d95f4122 MG |
3072 | return false; |
3073 | ||
3074 | /* Tell the scheduler that we'd really like pse to run next. */ | |
3075 | set_next_buddy(se); | |
3076 | ||
d95f4122 MG |
3077 | yield_task_fair(rq); |
3078 | ||
3079 | return true; | |
3080 | } | |
3081 | ||
681f3e68 | 3082 | #ifdef CONFIG_SMP |
bf0f6f24 IM |
3083 | /************************************************** |
3084 | * Fair scheduling class load-balancing methods: | |
3085 | */ | |
3086 | ||
1e3c88bd PZ |
3087 | /* |
3088 | * pull_task - move a task from a remote runqueue to the local runqueue. | |
3089 | * Both runqueues must be locked. | |
3090 | */ | |
3091 | static void pull_task(struct rq *src_rq, struct task_struct *p, | |
3092 | struct rq *this_rq, int this_cpu) | |
3093 | { | |
3094 | deactivate_task(src_rq, p, 0); | |
3095 | set_task_cpu(p, this_cpu); | |
3096 | activate_task(this_rq, p, 0); | |
3097 | check_preempt_curr(this_rq, p, 0); | |
3098 | } | |
3099 | ||
029632fb PZ |
3100 | /* |
3101 | * Is this task likely cache-hot: | |
3102 | */ | |
3103 | static int | |
3104 | task_hot(struct task_struct *p, u64 now, struct sched_domain *sd) | |
3105 | { | |
3106 | s64 delta; | |
3107 | ||
3108 | if (p->sched_class != &fair_sched_class) | |
3109 | return 0; | |
3110 | ||
3111 | if (unlikely(p->policy == SCHED_IDLE)) | |
3112 | return 0; | |
3113 | ||
3114 | /* | |
3115 | * Buddy candidates are cache hot: | |
3116 | */ | |
3117 | if (sched_feat(CACHE_HOT_BUDDY) && this_rq()->nr_running && | |
3118 | (&p->se == cfs_rq_of(&p->se)->next || | |
3119 | &p->se == cfs_rq_of(&p->se)->last)) | |
3120 | return 1; | |
3121 | ||
3122 | if (sysctl_sched_migration_cost == -1) | |
3123 | return 1; | |
3124 | if (sysctl_sched_migration_cost == 0) | |
3125 | return 0; | |
3126 | ||
3127 | delta = now - p->se.exec_start; | |
3128 | ||
3129 | return delta < (s64)sysctl_sched_migration_cost; | |
3130 | } | |
3131 | ||
1e3c88bd PZ |
3132 | /* |
3133 | * can_migrate_task - may task p from runqueue rq be migrated to this_cpu? | |
3134 | */ | |
3135 | static | |
3136 | int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu, | |
3137 | struct sched_domain *sd, enum cpu_idle_type idle, | |
3138 | int *all_pinned) | |
3139 | { | |
3140 | int tsk_cache_hot = 0; | |
3141 | /* | |
3142 | * We do not migrate tasks that are: | |
3143 | * 1) running (obviously), or | |
3144 | * 2) cannot be migrated to this CPU due to cpus_allowed, or | |
3145 | * 3) are cache-hot on their current CPU. | |
3146 | */ | |
fa17b507 | 3147 | if (!cpumask_test_cpu(this_cpu, tsk_cpus_allowed(p))) { |
41acab88 | 3148 | schedstat_inc(p, se.statistics.nr_failed_migrations_affine); |
1e3c88bd PZ |
3149 | return 0; |
3150 | } | |
3151 | *all_pinned = 0; | |
3152 | ||
3153 | if (task_running(rq, p)) { | |
41acab88 | 3154 | schedstat_inc(p, se.statistics.nr_failed_migrations_running); |
1e3c88bd PZ |
3155 | return 0; |
3156 | } | |
3157 | ||
3158 | /* | |
3159 | * Aggressive migration if: | |
3160 | * 1) task is cache cold, or | |
3161 | * 2) too many balance attempts have failed. | |
3162 | */ | |
3163 | ||
305e6835 | 3164 | tsk_cache_hot = task_hot(p, rq->clock_task, sd); |
1e3c88bd PZ |
3165 | if (!tsk_cache_hot || |
3166 | sd->nr_balance_failed > sd->cache_nice_tries) { | |
3167 | #ifdef CONFIG_SCHEDSTATS | |
3168 | if (tsk_cache_hot) { | |
3169 | schedstat_inc(sd, lb_hot_gained[idle]); | |
41acab88 | 3170 | schedstat_inc(p, se.statistics.nr_forced_migrations); |
1e3c88bd PZ |
3171 | } |
3172 | #endif | |
3173 | return 1; | |
3174 | } | |
3175 | ||
3176 | if (tsk_cache_hot) { | |
41acab88 | 3177 | schedstat_inc(p, se.statistics.nr_failed_migrations_hot); |
1e3c88bd PZ |
3178 | return 0; |
3179 | } | |
3180 | return 1; | |
3181 | } | |
3182 | ||
897c395f PZ |
3183 | /* |
3184 | * move_one_task tries to move exactly one task from busiest to this_rq, as | |
3185 | * part of active balancing operations within "domain". | |
3186 | * Returns 1 if successful and 0 otherwise. | |
3187 | * | |
3188 | * Called with both runqueues locked. | |
3189 | */ | |
3190 | static int | |
3191 | move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
3192 | struct sched_domain *sd, enum cpu_idle_type idle) | |
3193 | { | |
3194 | struct task_struct *p, *n; | |
3195 | struct cfs_rq *cfs_rq; | |
3196 | int pinned = 0; | |
3197 | ||
3198 | for_each_leaf_cfs_rq(busiest, cfs_rq) { | |
3199 | list_for_each_entry_safe(p, n, &cfs_rq->tasks, se.group_node) { | |
64660c86 PT |
3200 | if (throttled_lb_pair(task_group(p), |
3201 | busiest->cpu, this_cpu)) | |
3202 | break; | |
897c395f PZ |
3203 | |
3204 | if (!can_migrate_task(p, busiest, this_cpu, | |
3205 | sd, idle, &pinned)) | |
3206 | continue; | |
3207 | ||
3208 | pull_task(busiest, p, this_rq, this_cpu); | |
3209 | /* | |
3210 | * Right now, this is only the second place pull_task() | |
3211 | * is called, so we can safely collect pull_task() | |
3212 | * stats here rather than inside pull_task(). | |
3213 | */ | |
3214 | schedstat_inc(sd, lb_gained[idle]); | |
3215 | return 1; | |
3216 | } | |
3217 | } | |
3218 | ||
3219 | return 0; | |
3220 | } | |
3221 | ||
1e3c88bd PZ |
3222 | static unsigned long |
3223 | balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
3224 | unsigned long max_load_move, struct sched_domain *sd, | |
3225 | enum cpu_idle_type idle, int *all_pinned, | |
931aeeda | 3226 | struct cfs_rq *busiest_cfs_rq) |
1e3c88bd | 3227 | { |
b30aef17 | 3228 | int loops = 0, pulled = 0; |
1e3c88bd | 3229 | long rem_load_move = max_load_move; |
ee00e66f | 3230 | struct task_struct *p, *n; |
1e3c88bd PZ |
3231 | |
3232 | if (max_load_move == 0) | |
3233 | goto out; | |
3234 | ||
ee00e66f PZ |
3235 | list_for_each_entry_safe(p, n, &busiest_cfs_rq->tasks, se.group_node) { |
3236 | if (loops++ > sysctl_sched_nr_migrate) | |
3237 | break; | |
1e3c88bd | 3238 | |
ee00e66f | 3239 | if ((p->se.load.weight >> 1) > rem_load_move || |
b30aef17 KC |
3240 | !can_migrate_task(p, busiest, this_cpu, sd, idle, |
3241 | all_pinned)) | |
ee00e66f | 3242 | continue; |
1e3c88bd | 3243 | |
ee00e66f PZ |
3244 | pull_task(busiest, p, this_rq, this_cpu); |
3245 | pulled++; | |
3246 | rem_load_move -= p->se.load.weight; | |
1e3c88bd PZ |
3247 | |
3248 | #ifdef CONFIG_PREEMPT | |
ee00e66f PZ |
3249 | /* |
3250 | * NEWIDLE balancing is a source of latency, so preemptible | |
3251 | * kernels will stop after the first task is pulled to minimize | |
3252 | * the critical section. | |
3253 | */ | |
3254 | if (idle == CPU_NEWLY_IDLE) | |
3255 | break; | |
1e3c88bd PZ |
3256 | #endif |
3257 | ||
ee00e66f PZ |
3258 | /* |
3259 | * We only want to steal up to the prescribed amount of | |
3260 | * weighted load. | |
3261 | */ | |
3262 | if (rem_load_move <= 0) | |
3263 | break; | |
1e3c88bd PZ |
3264 | } |
3265 | out: | |
3266 | /* | |
3267 | * Right now, this is one of only two places pull_task() is called, | |
3268 | * so we can safely collect pull_task() stats here rather than | |
3269 | * inside pull_task(). | |
3270 | */ | |
3271 | schedstat_add(sd, lb_gained[idle], pulled); | |
3272 | ||
1e3c88bd PZ |
3273 | return max_load_move - rem_load_move; |
3274 | } | |
3275 | ||
230059de | 3276 | #ifdef CONFIG_FAIR_GROUP_SCHED |
9e3081ca PZ |
3277 | /* |
3278 | * update tg->load_weight by folding this cpu's load_avg | |
3279 | */ | |
67e86250 | 3280 | static int update_shares_cpu(struct task_group *tg, int cpu) |
9e3081ca PZ |
3281 | { |
3282 | struct cfs_rq *cfs_rq; | |
3283 | unsigned long flags; | |
3284 | struct rq *rq; | |
9e3081ca PZ |
3285 | |
3286 | if (!tg->se[cpu]) | |
3287 | return 0; | |
3288 | ||
3289 | rq = cpu_rq(cpu); | |
3290 | cfs_rq = tg->cfs_rq[cpu]; | |
3291 | ||
3292 | raw_spin_lock_irqsave(&rq->lock, flags); | |
3293 | ||
3294 | update_rq_clock(rq); | |
d6b55918 | 3295 | update_cfs_load(cfs_rq, 1); |
9e3081ca PZ |
3296 | |
3297 | /* | |
3298 | * We need to update shares after updating tg->load_weight in | |
3299 | * order to adjust the weight of groups with long running tasks. | |
3300 | */ | |
6d5ab293 | 3301 | update_cfs_shares(cfs_rq); |
9e3081ca PZ |
3302 | |
3303 | raw_spin_unlock_irqrestore(&rq->lock, flags); | |
3304 | ||
3305 | return 0; | |
3306 | } | |
3307 | ||
3308 | static void update_shares(int cpu) | |
3309 | { | |
3310 | struct cfs_rq *cfs_rq; | |
3311 | struct rq *rq = cpu_rq(cpu); | |
3312 | ||
3313 | rcu_read_lock(); | |
9763b67f PZ |
3314 | /* |
3315 | * Iterates the task_group tree in a bottom up fashion, see | |
3316 | * list_add_leaf_cfs_rq() for details. | |
3317 | */ | |
64660c86 PT |
3318 | for_each_leaf_cfs_rq(rq, cfs_rq) { |
3319 | /* throttled entities do not contribute to load */ | |
3320 | if (throttled_hierarchy(cfs_rq)) | |
3321 | continue; | |
3322 | ||
67e86250 | 3323 | update_shares_cpu(cfs_rq->tg, cpu); |
64660c86 | 3324 | } |
9e3081ca PZ |
3325 | rcu_read_unlock(); |
3326 | } | |
3327 | ||
9763b67f PZ |
3328 | /* |
3329 | * Compute the cpu's hierarchical load factor for each task group. | |
3330 | * This needs to be done in a top-down fashion because the load of a child | |
3331 | * group is a fraction of its parents load. | |
3332 | */ | |
3333 | static int tg_load_down(struct task_group *tg, void *data) | |
3334 | { | |
3335 | unsigned long load; | |
3336 | long cpu = (long)data; | |
3337 | ||
3338 | if (!tg->parent) { | |
3339 | load = cpu_rq(cpu)->load.weight; | |
3340 | } else { | |
3341 | load = tg->parent->cfs_rq[cpu]->h_load; | |
3342 | load *= tg->se[cpu]->load.weight; | |
3343 | load /= tg->parent->cfs_rq[cpu]->load.weight + 1; | |
3344 | } | |
3345 | ||
3346 | tg->cfs_rq[cpu]->h_load = load; | |
3347 | ||
3348 | return 0; | |
3349 | } | |
3350 | ||
3351 | static void update_h_load(long cpu) | |
3352 | { | |
3353 | walk_tg_tree(tg_load_down, tg_nop, (void *)cpu); | |
3354 | } | |
3355 | ||
230059de PZ |
3356 | static unsigned long |
3357 | load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
3358 | unsigned long max_load_move, | |
3359 | struct sched_domain *sd, enum cpu_idle_type idle, | |
931aeeda | 3360 | int *all_pinned) |
230059de PZ |
3361 | { |
3362 | long rem_load_move = max_load_move; | |
9763b67f | 3363 | struct cfs_rq *busiest_cfs_rq; |
230059de PZ |
3364 | |
3365 | rcu_read_lock(); | |
9763b67f | 3366 | update_h_load(cpu_of(busiest)); |
230059de | 3367 | |
9763b67f | 3368 | for_each_leaf_cfs_rq(busiest, busiest_cfs_rq) { |
230059de PZ |
3369 | unsigned long busiest_h_load = busiest_cfs_rq->h_load; |
3370 | unsigned long busiest_weight = busiest_cfs_rq->load.weight; | |
3371 | u64 rem_load, moved_load; | |
3372 | ||
3373 | /* | |
64660c86 | 3374 | * empty group or part of a throttled hierarchy |
230059de | 3375 | */ |
64660c86 PT |
3376 | if (!busiest_cfs_rq->task_weight || |
3377 | throttled_lb_pair(busiest_cfs_rq->tg, cpu_of(busiest), this_cpu)) | |
230059de PZ |
3378 | continue; |
3379 | ||
3380 | rem_load = (u64)rem_load_move * busiest_weight; | |
3381 | rem_load = div_u64(rem_load, busiest_h_load + 1); | |
3382 | ||
3383 | moved_load = balance_tasks(this_rq, this_cpu, busiest, | |
931aeeda | 3384 | rem_load, sd, idle, all_pinned, |
230059de PZ |
3385 | busiest_cfs_rq); |
3386 | ||
3387 | if (!moved_load) | |
3388 | continue; | |
3389 | ||
3390 | moved_load *= busiest_h_load; | |
3391 | moved_load = div_u64(moved_load, busiest_weight + 1); | |
3392 | ||
3393 | rem_load_move -= moved_load; | |
3394 | if (rem_load_move < 0) | |
3395 | break; | |
3396 | } | |
3397 | rcu_read_unlock(); | |
3398 | ||
3399 | return max_load_move - rem_load_move; | |
3400 | } | |
3401 | #else | |
9e3081ca PZ |
3402 | static inline void update_shares(int cpu) |
3403 | { | |
3404 | } | |
3405 | ||
230059de PZ |
3406 | static unsigned long |
3407 | load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
3408 | unsigned long max_load_move, | |
3409 | struct sched_domain *sd, enum cpu_idle_type idle, | |
931aeeda | 3410 | int *all_pinned) |
230059de PZ |
3411 | { |
3412 | return balance_tasks(this_rq, this_cpu, busiest, | |
3413 | max_load_move, sd, idle, all_pinned, | |
931aeeda | 3414 | &busiest->cfs); |
230059de PZ |
3415 | } |
3416 | #endif | |
3417 | ||
1e3c88bd PZ |
3418 | /* |
3419 | * move_tasks tries to move up to max_load_move weighted load from busiest to | |
3420 | * this_rq, as part of a balancing operation within domain "sd". | |
3421 | * Returns 1 if successful and 0 otherwise. | |
3422 | * | |
3423 | * Called with both runqueues locked. | |
3424 | */ | |
3425 | static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
3426 | unsigned long max_load_move, | |
3427 | struct sched_domain *sd, enum cpu_idle_type idle, | |
3428 | int *all_pinned) | |
3429 | { | |
3d45fd80 | 3430 | unsigned long total_load_moved = 0, load_moved; |
1e3c88bd PZ |
3431 | |
3432 | do { | |
3d45fd80 | 3433 | load_moved = load_balance_fair(this_rq, this_cpu, busiest, |
1e3c88bd | 3434 | max_load_move - total_load_moved, |
931aeeda | 3435 | sd, idle, all_pinned); |
3d45fd80 PZ |
3436 | |
3437 | total_load_moved += load_moved; | |
1e3c88bd PZ |
3438 | |
3439 | #ifdef CONFIG_PREEMPT | |
3440 | /* | |
3441 | * NEWIDLE balancing is a source of latency, so preemptible | |
3442 | * kernels will stop after the first task is pulled to minimize | |
3443 | * the critical section. | |
3444 | */ | |
3445 | if (idle == CPU_NEWLY_IDLE && this_rq->nr_running) | |
3446 | break; | |
baa8c110 PZ |
3447 | |
3448 | if (raw_spin_is_contended(&this_rq->lock) || | |
3449 | raw_spin_is_contended(&busiest->lock)) | |
3450 | break; | |
1e3c88bd | 3451 | #endif |
3d45fd80 | 3452 | } while (load_moved && max_load_move > total_load_moved); |
1e3c88bd PZ |
3453 | |
3454 | return total_load_moved > 0; | |
3455 | } | |
3456 | ||
1e3c88bd PZ |
3457 | /********** Helpers for find_busiest_group ************************/ |
3458 | /* | |
3459 | * sd_lb_stats - Structure to store the statistics of a sched_domain | |
3460 | * during load balancing. | |
3461 | */ | |
3462 | struct sd_lb_stats { | |
3463 | struct sched_group *busiest; /* Busiest group in this sd */ | |
3464 | struct sched_group *this; /* Local group in this sd */ | |
3465 | unsigned long total_load; /* Total load of all groups in sd */ | |
3466 | unsigned long total_pwr; /* Total power of all groups in sd */ | |
3467 | unsigned long avg_load; /* Average load across all groups in sd */ | |
3468 | ||
3469 | /** Statistics of this group */ | |
3470 | unsigned long this_load; | |
3471 | unsigned long this_load_per_task; | |
3472 | unsigned long this_nr_running; | |
fab47622 | 3473 | unsigned long this_has_capacity; |
aae6d3dd | 3474 | unsigned int this_idle_cpus; |
1e3c88bd PZ |
3475 | |
3476 | /* Statistics of the busiest group */ | |
aae6d3dd | 3477 | unsigned int busiest_idle_cpus; |
1e3c88bd PZ |
3478 | unsigned long max_load; |
3479 | unsigned long busiest_load_per_task; | |
3480 | unsigned long busiest_nr_running; | |
dd5feea1 | 3481 | unsigned long busiest_group_capacity; |
fab47622 | 3482 | unsigned long busiest_has_capacity; |
aae6d3dd | 3483 | unsigned int busiest_group_weight; |
1e3c88bd PZ |
3484 | |
3485 | int group_imb; /* Is there imbalance in this sd */ | |
3486 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) | |
3487 | int power_savings_balance; /* Is powersave balance needed for this sd */ | |
3488 | struct sched_group *group_min; /* Least loaded group in sd */ | |
3489 | struct sched_group *group_leader; /* Group which relieves group_min */ | |
3490 | unsigned long min_load_per_task; /* load_per_task in group_min */ | |
3491 | unsigned long leader_nr_running; /* Nr running of group_leader */ | |
3492 | unsigned long min_nr_running; /* Nr running of group_min */ | |
3493 | #endif | |
3494 | }; | |
3495 | ||
3496 | /* | |
3497 | * sg_lb_stats - stats of a sched_group required for load_balancing | |
3498 | */ | |
3499 | struct sg_lb_stats { | |
3500 | unsigned long avg_load; /*Avg load across the CPUs of the group */ | |
3501 | unsigned long group_load; /* Total load over the CPUs of the group */ | |
3502 | unsigned long sum_nr_running; /* Nr tasks running in the group */ | |
3503 | unsigned long sum_weighted_load; /* Weighted load of group's tasks */ | |
3504 | unsigned long group_capacity; | |
aae6d3dd SS |
3505 | unsigned long idle_cpus; |
3506 | unsigned long group_weight; | |
1e3c88bd | 3507 | int group_imb; /* Is there an imbalance in the group ? */ |
fab47622 | 3508 | int group_has_capacity; /* Is there extra capacity in the group? */ |
1e3c88bd PZ |
3509 | }; |
3510 | ||
1e3c88bd PZ |
3511 | /** |
3512 | * get_sd_load_idx - Obtain the load index for a given sched domain. | |
3513 | * @sd: The sched_domain whose load_idx is to be obtained. | |
3514 | * @idle: The Idle status of the CPU for whose sd load_icx is obtained. | |
3515 | */ | |
3516 | static inline int get_sd_load_idx(struct sched_domain *sd, | |
3517 | enum cpu_idle_type idle) | |
3518 | { | |
3519 | int load_idx; | |
3520 | ||
3521 | switch (idle) { | |
3522 | case CPU_NOT_IDLE: | |
3523 | load_idx = sd->busy_idx; | |
3524 | break; | |
3525 | ||
3526 | case CPU_NEWLY_IDLE: | |
3527 | load_idx = sd->newidle_idx; | |
3528 | break; | |
3529 | default: | |
3530 | load_idx = sd->idle_idx; | |
3531 | break; | |
3532 | } | |
3533 | ||
3534 | return load_idx; | |
3535 | } | |
3536 | ||
3537 | ||
3538 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) | |
3539 | /** | |
3540 | * init_sd_power_savings_stats - Initialize power savings statistics for | |
3541 | * the given sched_domain, during load balancing. | |
3542 | * | |
3543 | * @sd: Sched domain whose power-savings statistics are to be initialized. | |
3544 | * @sds: Variable containing the statistics for sd. | |
3545 | * @idle: Idle status of the CPU at which we're performing load-balancing. | |
3546 | */ | |
3547 | static inline void init_sd_power_savings_stats(struct sched_domain *sd, | |
3548 | struct sd_lb_stats *sds, enum cpu_idle_type idle) | |
3549 | { | |
3550 | /* | |
3551 | * Busy processors will not participate in power savings | |
3552 | * balance. | |
3553 | */ | |
3554 | if (idle == CPU_NOT_IDLE || !(sd->flags & SD_POWERSAVINGS_BALANCE)) | |
3555 | sds->power_savings_balance = 0; | |
3556 | else { | |
3557 | sds->power_savings_balance = 1; | |
3558 | sds->min_nr_running = ULONG_MAX; | |
3559 | sds->leader_nr_running = 0; | |
3560 | } | |
3561 | } | |
3562 | ||
3563 | /** | |
3564 | * update_sd_power_savings_stats - Update the power saving stats for a | |
3565 | * sched_domain while performing load balancing. | |
3566 | * | |
3567 | * @group: sched_group belonging to the sched_domain under consideration. | |
3568 | * @sds: Variable containing the statistics of the sched_domain | |
3569 | * @local_group: Does group contain the CPU for which we're performing | |
3570 | * load balancing ? | |
3571 | * @sgs: Variable containing the statistics of the group. | |
3572 | */ | |
3573 | static inline void update_sd_power_savings_stats(struct sched_group *group, | |
3574 | struct sd_lb_stats *sds, int local_group, struct sg_lb_stats *sgs) | |
3575 | { | |
3576 | ||
3577 | if (!sds->power_savings_balance) | |
3578 | return; | |
3579 | ||
3580 | /* | |
3581 | * If the local group is idle or completely loaded | |
3582 | * no need to do power savings balance at this domain | |
3583 | */ | |
3584 | if (local_group && (sds->this_nr_running >= sgs->group_capacity || | |
3585 | !sds->this_nr_running)) | |
3586 | sds->power_savings_balance = 0; | |
3587 | ||
3588 | /* | |
3589 | * If a group is already running at full capacity or idle, | |
3590 | * don't include that group in power savings calculations | |
3591 | */ | |
3592 | if (!sds->power_savings_balance || | |
3593 | sgs->sum_nr_running >= sgs->group_capacity || | |
3594 | !sgs->sum_nr_running) | |
3595 | return; | |
3596 | ||
3597 | /* | |
3598 | * Calculate the group which has the least non-idle load. | |
3599 | * This is the group from where we need to pick up the load | |
3600 | * for saving power | |
3601 | */ | |
3602 | if ((sgs->sum_nr_running < sds->min_nr_running) || | |
3603 | (sgs->sum_nr_running == sds->min_nr_running && | |
3604 | group_first_cpu(group) > group_first_cpu(sds->group_min))) { | |
3605 | sds->group_min = group; | |
3606 | sds->min_nr_running = sgs->sum_nr_running; | |
3607 | sds->min_load_per_task = sgs->sum_weighted_load / | |
3608 | sgs->sum_nr_running; | |
3609 | } | |
3610 | ||
3611 | /* | |
3612 | * Calculate the group which is almost near its | |
3613 | * capacity but still has some space to pick up some load | |
3614 | * from other group and save more power | |
3615 | */ | |
3616 | if (sgs->sum_nr_running + 1 > sgs->group_capacity) | |
3617 | return; | |
3618 | ||
3619 | if (sgs->sum_nr_running > sds->leader_nr_running || | |
3620 | (sgs->sum_nr_running == sds->leader_nr_running && | |
3621 | group_first_cpu(group) < group_first_cpu(sds->group_leader))) { | |
3622 | sds->group_leader = group; | |
3623 | sds->leader_nr_running = sgs->sum_nr_running; | |
3624 | } | |
3625 | } | |
3626 | ||
3627 | /** | |
3628 | * check_power_save_busiest_group - see if there is potential for some power-savings balance | |
3629 | * @sds: Variable containing the statistics of the sched_domain | |
3630 | * under consideration. | |
3631 | * @this_cpu: Cpu at which we're currently performing load-balancing. | |
3632 | * @imbalance: Variable to store the imbalance. | |
3633 | * | |
3634 | * Description: | |
3635 | * Check if we have potential to perform some power-savings balance. | |
3636 | * If yes, set the busiest group to be the least loaded group in the | |
3637 | * sched_domain, so that it's CPUs can be put to idle. | |
3638 | * | |
3639 | * Returns 1 if there is potential to perform power-savings balance. | |
3640 | * Else returns 0. | |
3641 | */ | |
3642 | static inline int check_power_save_busiest_group(struct sd_lb_stats *sds, | |
3643 | int this_cpu, unsigned long *imbalance) | |
3644 | { | |
3645 | if (!sds->power_savings_balance) | |
3646 | return 0; | |
3647 | ||
3648 | if (sds->this != sds->group_leader || | |
3649 | sds->group_leader == sds->group_min) | |
3650 | return 0; | |
3651 | ||
3652 | *imbalance = sds->min_load_per_task; | |
3653 | sds->busiest = sds->group_min; | |
3654 | ||
3655 | return 1; | |
3656 | ||
3657 | } | |
3658 | #else /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */ | |
3659 | static inline void init_sd_power_savings_stats(struct sched_domain *sd, | |
3660 | struct sd_lb_stats *sds, enum cpu_idle_type idle) | |
3661 | { | |
3662 | return; | |
3663 | } | |
3664 | ||
3665 | static inline void update_sd_power_savings_stats(struct sched_group *group, | |
3666 | struct sd_lb_stats *sds, int local_group, struct sg_lb_stats *sgs) | |
3667 | { | |
3668 | return; | |
3669 | } | |
3670 | ||
3671 | static inline int check_power_save_busiest_group(struct sd_lb_stats *sds, | |
3672 | int this_cpu, unsigned long *imbalance) | |
3673 | { | |
3674 | return 0; | |
3675 | } | |
3676 | #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */ | |
3677 | ||
3678 | ||
3679 | unsigned long default_scale_freq_power(struct sched_domain *sd, int cpu) | |
3680 | { | |
1399fa78 | 3681 | return SCHED_POWER_SCALE; |
1e3c88bd PZ |
3682 | } |
3683 | ||
3684 | unsigned long __weak arch_scale_freq_power(struct sched_domain *sd, int cpu) | |
3685 | { | |
3686 | return default_scale_freq_power(sd, cpu); | |
3687 | } | |
3688 | ||
3689 | unsigned long default_scale_smt_power(struct sched_domain *sd, int cpu) | |
3690 | { | |
669c55e9 | 3691 | unsigned long weight = sd->span_weight; |
1e3c88bd PZ |
3692 | unsigned long smt_gain = sd->smt_gain; |
3693 | ||
3694 | smt_gain /= weight; | |
3695 | ||
3696 | return smt_gain; | |
3697 | } | |
3698 | ||
3699 | unsigned long __weak arch_scale_smt_power(struct sched_domain *sd, int cpu) | |
3700 | { | |
3701 | return default_scale_smt_power(sd, cpu); | |
3702 | } | |
3703 | ||
3704 | unsigned long scale_rt_power(int cpu) | |
3705 | { | |
3706 | struct rq *rq = cpu_rq(cpu); | |
3707 | u64 total, available; | |
3708 | ||
1e3c88bd | 3709 | total = sched_avg_period() + (rq->clock - rq->age_stamp); |
aa483808 VP |
3710 | |
3711 | if (unlikely(total < rq->rt_avg)) { | |
3712 | /* Ensures that power won't end up being negative */ | |
3713 | available = 0; | |
3714 | } else { | |
3715 | available = total - rq->rt_avg; | |
3716 | } | |
1e3c88bd | 3717 | |
1399fa78 NR |
3718 | if (unlikely((s64)total < SCHED_POWER_SCALE)) |
3719 | total = SCHED_POWER_SCALE; | |
1e3c88bd | 3720 | |
1399fa78 | 3721 | total >>= SCHED_POWER_SHIFT; |
1e3c88bd PZ |
3722 | |
3723 | return div_u64(available, total); | |
3724 | } | |
3725 | ||
3726 | static void update_cpu_power(struct sched_domain *sd, int cpu) | |
3727 | { | |
669c55e9 | 3728 | unsigned long weight = sd->span_weight; |
1399fa78 | 3729 | unsigned long power = SCHED_POWER_SCALE; |
1e3c88bd PZ |
3730 | struct sched_group *sdg = sd->groups; |
3731 | ||
1e3c88bd PZ |
3732 | if ((sd->flags & SD_SHARE_CPUPOWER) && weight > 1) { |
3733 | if (sched_feat(ARCH_POWER)) | |
3734 | power *= arch_scale_smt_power(sd, cpu); | |
3735 | else | |
3736 | power *= default_scale_smt_power(sd, cpu); | |
3737 | ||
1399fa78 | 3738 | power >>= SCHED_POWER_SHIFT; |
1e3c88bd PZ |
3739 | } |
3740 | ||
9c3f75cb | 3741 | sdg->sgp->power_orig = power; |
9d5efe05 SV |
3742 | |
3743 | if (sched_feat(ARCH_POWER)) | |
3744 | power *= arch_scale_freq_power(sd, cpu); | |
3745 | else | |
3746 | power *= default_scale_freq_power(sd, cpu); | |
3747 | ||
1399fa78 | 3748 | power >>= SCHED_POWER_SHIFT; |
9d5efe05 | 3749 | |
1e3c88bd | 3750 | power *= scale_rt_power(cpu); |
1399fa78 | 3751 | power >>= SCHED_POWER_SHIFT; |
1e3c88bd PZ |
3752 | |
3753 | if (!power) | |
3754 | power = 1; | |
3755 | ||
e51fd5e2 | 3756 | cpu_rq(cpu)->cpu_power = power; |
9c3f75cb | 3757 | sdg->sgp->power = power; |
1e3c88bd PZ |
3758 | } |
3759 | ||
029632fb | 3760 | void update_group_power(struct sched_domain *sd, int cpu) |
1e3c88bd PZ |
3761 | { |
3762 | struct sched_domain *child = sd->child; | |
3763 | struct sched_group *group, *sdg = sd->groups; | |
3764 | unsigned long power; | |
3765 | ||
3766 | if (!child) { | |
3767 | update_cpu_power(sd, cpu); | |
3768 | return; | |
3769 | } | |
3770 | ||
3771 | power = 0; | |
3772 | ||
3773 | group = child->groups; | |
3774 | do { | |
9c3f75cb | 3775 | power += group->sgp->power; |
1e3c88bd PZ |
3776 | group = group->next; |
3777 | } while (group != child->groups); | |
3778 | ||
9c3f75cb | 3779 | sdg->sgp->power = power; |
1e3c88bd PZ |
3780 | } |
3781 | ||
9d5efe05 SV |
3782 | /* |
3783 | * Try and fix up capacity for tiny siblings, this is needed when | |
3784 | * things like SD_ASYM_PACKING need f_b_g to select another sibling | |
3785 | * which on its own isn't powerful enough. | |
3786 | * | |
3787 | * See update_sd_pick_busiest() and check_asym_packing(). | |
3788 | */ | |
3789 | static inline int | |
3790 | fix_small_capacity(struct sched_domain *sd, struct sched_group *group) | |
3791 | { | |
3792 | /* | |
1399fa78 | 3793 | * Only siblings can have significantly less than SCHED_POWER_SCALE |
9d5efe05 | 3794 | */ |
a6c75f2f | 3795 | if (!(sd->flags & SD_SHARE_CPUPOWER)) |
9d5efe05 SV |
3796 | return 0; |
3797 | ||
3798 | /* | |
3799 | * If ~90% of the cpu_power is still there, we're good. | |
3800 | */ | |
9c3f75cb | 3801 | if (group->sgp->power * 32 > group->sgp->power_orig * 29) |
9d5efe05 SV |
3802 | return 1; |
3803 | ||
3804 | return 0; | |
3805 | } | |
3806 | ||
1e3c88bd PZ |
3807 | /** |
3808 | * update_sg_lb_stats - Update sched_group's statistics for load balancing. | |
3809 | * @sd: The sched_domain whose statistics are to be updated. | |
3810 | * @group: sched_group whose statistics are to be updated. | |
3811 | * @this_cpu: Cpu for which load balance is currently performed. | |
3812 | * @idle: Idle status of this_cpu | |
3813 | * @load_idx: Load index of sched_domain of this_cpu for load calc. | |
1e3c88bd PZ |
3814 | * @local_group: Does group contain this_cpu. |
3815 | * @cpus: Set of cpus considered for load balancing. | |
3816 | * @balance: Should we balance. | |
3817 | * @sgs: variable to hold the statistics for this group. | |
3818 | */ | |
3819 | static inline void update_sg_lb_stats(struct sched_domain *sd, | |
3820 | struct sched_group *group, int this_cpu, | |
46e49b38 | 3821 | enum cpu_idle_type idle, int load_idx, |
1e3c88bd PZ |
3822 | int local_group, const struct cpumask *cpus, |
3823 | int *balance, struct sg_lb_stats *sgs) | |
3824 | { | |
2582f0eb | 3825 | unsigned long load, max_cpu_load, min_cpu_load, max_nr_running; |
1e3c88bd PZ |
3826 | int i; |
3827 | unsigned int balance_cpu = -1, first_idle_cpu = 0; | |
dd5feea1 | 3828 | unsigned long avg_load_per_task = 0; |
1e3c88bd | 3829 | |
871e35bc | 3830 | if (local_group) |
1e3c88bd | 3831 | balance_cpu = group_first_cpu(group); |
1e3c88bd PZ |
3832 | |
3833 | /* Tally up the load of all CPUs in the group */ | |
1e3c88bd PZ |
3834 | max_cpu_load = 0; |
3835 | min_cpu_load = ~0UL; | |
2582f0eb | 3836 | max_nr_running = 0; |
1e3c88bd PZ |
3837 | |
3838 | for_each_cpu_and(i, sched_group_cpus(group), cpus) { | |
3839 | struct rq *rq = cpu_rq(i); | |
3840 | ||
1e3c88bd PZ |
3841 | /* Bias balancing toward cpus of our domain */ |
3842 | if (local_group) { | |
3843 | if (idle_cpu(i) && !first_idle_cpu) { | |
3844 | first_idle_cpu = 1; | |
3845 | balance_cpu = i; | |
3846 | } | |
3847 | ||
3848 | load = target_load(i, load_idx); | |
3849 | } else { | |
3850 | load = source_load(i, load_idx); | |
2582f0eb | 3851 | if (load > max_cpu_load) { |
1e3c88bd | 3852 | max_cpu_load = load; |
2582f0eb NR |
3853 | max_nr_running = rq->nr_running; |
3854 | } | |
1e3c88bd PZ |
3855 | if (min_cpu_load > load) |
3856 | min_cpu_load = load; | |
3857 | } | |
3858 | ||
3859 | sgs->group_load += load; | |
3860 | sgs->sum_nr_running += rq->nr_running; | |
3861 | sgs->sum_weighted_load += weighted_cpuload(i); | |
aae6d3dd SS |
3862 | if (idle_cpu(i)) |
3863 | sgs->idle_cpus++; | |
1e3c88bd PZ |
3864 | } |
3865 | ||
3866 | /* | |
3867 | * First idle cpu or the first cpu(busiest) in this sched group | |
3868 | * is eligible for doing load balancing at this and above | |
3869 | * domains. In the newly idle case, we will allow all the cpu's | |
3870 | * to do the newly idle load balance. | |
3871 | */ | |
bbc8cb5b PZ |
3872 | if (idle != CPU_NEWLY_IDLE && local_group) { |
3873 | if (balance_cpu != this_cpu) { | |
3874 | *balance = 0; | |
3875 | return; | |
3876 | } | |
3877 | update_group_power(sd, this_cpu); | |
1e3c88bd PZ |
3878 | } |
3879 | ||
3880 | /* Adjust by relative CPU power of the group */ | |
9c3f75cb | 3881 | sgs->avg_load = (sgs->group_load*SCHED_POWER_SCALE) / group->sgp->power; |
1e3c88bd | 3882 | |
1e3c88bd PZ |
3883 | /* |
3884 | * Consider the group unbalanced when the imbalance is larger | |
866ab43e | 3885 | * than the average weight of a task. |
1e3c88bd PZ |
3886 | * |
3887 | * APZ: with cgroup the avg task weight can vary wildly and | |
3888 | * might not be a suitable number - should we keep a | |
3889 | * normalized nr_running number somewhere that negates | |
3890 | * the hierarchy? | |
3891 | */ | |
dd5feea1 SS |
3892 | if (sgs->sum_nr_running) |
3893 | avg_load_per_task = sgs->sum_weighted_load / sgs->sum_nr_running; | |
1e3c88bd | 3894 | |
866ab43e | 3895 | if ((max_cpu_load - min_cpu_load) >= avg_load_per_task && max_nr_running > 1) |
1e3c88bd PZ |
3896 | sgs->group_imb = 1; |
3897 | ||
9c3f75cb | 3898 | sgs->group_capacity = DIV_ROUND_CLOSEST(group->sgp->power, |
1399fa78 | 3899 | SCHED_POWER_SCALE); |
9d5efe05 SV |
3900 | if (!sgs->group_capacity) |
3901 | sgs->group_capacity = fix_small_capacity(sd, group); | |
aae6d3dd | 3902 | sgs->group_weight = group->group_weight; |
fab47622 NR |
3903 | |
3904 | if (sgs->group_capacity > sgs->sum_nr_running) | |
3905 | sgs->group_has_capacity = 1; | |
1e3c88bd PZ |
3906 | } |
3907 | ||
532cb4c4 MN |
3908 | /** |
3909 | * update_sd_pick_busiest - return 1 on busiest group | |
3910 | * @sd: sched_domain whose statistics are to be checked | |
3911 | * @sds: sched_domain statistics | |
3912 | * @sg: sched_group candidate to be checked for being the busiest | |
b6b12294 MN |
3913 | * @sgs: sched_group statistics |
3914 | * @this_cpu: the current cpu | |
532cb4c4 MN |
3915 | * |
3916 | * Determine if @sg is a busier group than the previously selected | |
3917 | * busiest group. | |
3918 | */ | |
3919 | static bool update_sd_pick_busiest(struct sched_domain *sd, | |
3920 | struct sd_lb_stats *sds, | |
3921 | struct sched_group *sg, | |
3922 | struct sg_lb_stats *sgs, | |
3923 | int this_cpu) | |
3924 | { | |
3925 | if (sgs->avg_load <= sds->max_load) | |
3926 | return false; | |
3927 | ||
3928 | if (sgs->sum_nr_running > sgs->group_capacity) | |
3929 | return true; | |
3930 | ||
3931 | if (sgs->group_imb) | |
3932 | return true; | |
3933 | ||
3934 | /* | |
3935 | * ASYM_PACKING needs to move all the work to the lowest | |
3936 | * numbered CPUs in the group, therefore mark all groups | |
3937 | * higher than ourself as busy. | |
3938 | */ | |
3939 | if ((sd->flags & SD_ASYM_PACKING) && sgs->sum_nr_running && | |
3940 | this_cpu < group_first_cpu(sg)) { | |
3941 | if (!sds->busiest) | |
3942 | return true; | |
3943 | ||
3944 | if (group_first_cpu(sds->busiest) > group_first_cpu(sg)) | |
3945 | return true; | |
3946 | } | |
3947 | ||
3948 | return false; | |
3949 | } | |
3950 | ||
1e3c88bd | 3951 | /** |
461819ac | 3952 | * update_sd_lb_stats - Update sched_domain's statistics for load balancing. |
1e3c88bd PZ |
3953 | * @sd: sched_domain whose statistics are to be updated. |
3954 | * @this_cpu: Cpu for which load balance is currently performed. | |
3955 | * @idle: Idle status of this_cpu | |
1e3c88bd PZ |
3956 | * @cpus: Set of cpus considered for load balancing. |
3957 | * @balance: Should we balance. | |
3958 | * @sds: variable to hold the statistics for this sched_domain. | |
3959 | */ | |
3960 | static inline void update_sd_lb_stats(struct sched_domain *sd, int this_cpu, | |
46e49b38 VP |
3961 | enum cpu_idle_type idle, const struct cpumask *cpus, |
3962 | int *balance, struct sd_lb_stats *sds) | |
1e3c88bd PZ |
3963 | { |
3964 | struct sched_domain *child = sd->child; | |
532cb4c4 | 3965 | struct sched_group *sg = sd->groups; |
1e3c88bd PZ |
3966 | struct sg_lb_stats sgs; |
3967 | int load_idx, prefer_sibling = 0; | |
3968 | ||
3969 | if (child && child->flags & SD_PREFER_SIBLING) | |
3970 | prefer_sibling = 1; | |
3971 | ||
3972 | init_sd_power_savings_stats(sd, sds, idle); | |
3973 | load_idx = get_sd_load_idx(sd, idle); | |
3974 | ||
3975 | do { | |
3976 | int local_group; | |
3977 | ||
532cb4c4 | 3978 | local_group = cpumask_test_cpu(this_cpu, sched_group_cpus(sg)); |
1e3c88bd | 3979 | memset(&sgs, 0, sizeof(sgs)); |
46e49b38 | 3980 | update_sg_lb_stats(sd, sg, this_cpu, idle, load_idx, |
1e3c88bd PZ |
3981 | local_group, cpus, balance, &sgs); |
3982 | ||
8f190fb3 | 3983 | if (local_group && !(*balance)) |
1e3c88bd PZ |
3984 | return; |
3985 | ||
3986 | sds->total_load += sgs.group_load; | |
9c3f75cb | 3987 | sds->total_pwr += sg->sgp->power; |
1e3c88bd PZ |
3988 | |
3989 | /* | |
3990 | * In case the child domain prefers tasks go to siblings | |
532cb4c4 | 3991 | * first, lower the sg capacity to one so that we'll try |
75dd321d NR |
3992 | * and move all the excess tasks away. We lower the capacity |
3993 | * of a group only if the local group has the capacity to fit | |
3994 | * these excess tasks, i.e. nr_running < group_capacity. The | |
3995 | * extra check prevents the case where you always pull from the | |
3996 | * heaviest group when it is already under-utilized (possible | |
3997 | * with a large weight task outweighs the tasks on the system). | |
1e3c88bd | 3998 | */ |
75dd321d | 3999 | if (prefer_sibling && !local_group && sds->this_has_capacity) |
1e3c88bd PZ |
4000 | sgs.group_capacity = min(sgs.group_capacity, 1UL); |
4001 | ||
4002 | if (local_group) { | |
4003 | sds->this_load = sgs.avg_load; | |
532cb4c4 | 4004 | sds->this = sg; |
1e3c88bd PZ |
4005 | sds->this_nr_running = sgs.sum_nr_running; |
4006 | sds->this_load_per_task = sgs.sum_weighted_load; | |
fab47622 | 4007 | sds->this_has_capacity = sgs.group_has_capacity; |
aae6d3dd | 4008 | sds->this_idle_cpus = sgs.idle_cpus; |
532cb4c4 | 4009 | } else if (update_sd_pick_busiest(sd, sds, sg, &sgs, this_cpu)) { |
1e3c88bd | 4010 | sds->max_load = sgs.avg_load; |
532cb4c4 | 4011 | sds->busiest = sg; |
1e3c88bd | 4012 | sds->busiest_nr_running = sgs.sum_nr_running; |
aae6d3dd | 4013 | sds->busiest_idle_cpus = sgs.idle_cpus; |
dd5feea1 | 4014 | sds->busiest_group_capacity = sgs.group_capacity; |
1e3c88bd | 4015 | sds->busiest_load_per_task = sgs.sum_weighted_load; |
fab47622 | 4016 | sds->busiest_has_capacity = sgs.group_has_capacity; |
aae6d3dd | 4017 | sds->busiest_group_weight = sgs.group_weight; |
1e3c88bd PZ |
4018 | sds->group_imb = sgs.group_imb; |
4019 | } | |
4020 | ||
532cb4c4 MN |
4021 | update_sd_power_savings_stats(sg, sds, local_group, &sgs); |
4022 | sg = sg->next; | |
4023 | } while (sg != sd->groups); | |
4024 | } | |
4025 | ||
532cb4c4 MN |
4026 | /** |
4027 | * check_asym_packing - Check to see if the group is packed into the | |
4028 | * sched doman. | |
4029 | * | |
4030 | * This is primarily intended to used at the sibling level. Some | |
4031 | * cores like POWER7 prefer to use lower numbered SMT threads. In the | |
4032 | * case of POWER7, it can move to lower SMT modes only when higher | |
4033 | * threads are idle. When in lower SMT modes, the threads will | |
4034 | * perform better since they share less core resources. Hence when we | |
4035 | * have idle threads, we want them to be the higher ones. | |
4036 | * | |
4037 | * This packing function is run on idle threads. It checks to see if | |
4038 | * the busiest CPU in this domain (core in the P7 case) has a higher | |
4039 | * CPU number than the packing function is being run on. Here we are | |
4040 | * assuming lower CPU number will be equivalent to lower a SMT thread | |
4041 | * number. | |
4042 | * | |
b6b12294 MN |
4043 | * Returns 1 when packing is required and a task should be moved to |
4044 | * this CPU. The amount of the imbalance is returned in *imbalance. | |
4045 | * | |
532cb4c4 MN |
4046 | * @sd: The sched_domain whose packing is to be checked. |
4047 | * @sds: Statistics of the sched_domain which is to be packed | |
4048 | * @this_cpu: The cpu at whose sched_domain we're performing load-balance. | |
4049 | * @imbalance: returns amount of imbalanced due to packing. | |
532cb4c4 MN |
4050 | */ |
4051 | static int check_asym_packing(struct sched_domain *sd, | |
4052 | struct sd_lb_stats *sds, | |
4053 | int this_cpu, unsigned long *imbalance) | |
4054 | { | |
4055 | int busiest_cpu; | |
4056 | ||
4057 | if (!(sd->flags & SD_ASYM_PACKING)) | |
4058 | return 0; | |
4059 | ||
4060 | if (!sds->busiest) | |
4061 | return 0; | |
4062 | ||
4063 | busiest_cpu = group_first_cpu(sds->busiest); | |
4064 | if (this_cpu > busiest_cpu) | |
4065 | return 0; | |
4066 | ||
9c3f75cb | 4067 | *imbalance = DIV_ROUND_CLOSEST(sds->max_load * sds->busiest->sgp->power, |
1399fa78 | 4068 | SCHED_POWER_SCALE); |
532cb4c4 | 4069 | return 1; |
1e3c88bd PZ |
4070 | } |
4071 | ||
4072 | /** | |
4073 | * fix_small_imbalance - Calculate the minor imbalance that exists | |
4074 | * amongst the groups of a sched_domain, during | |
4075 | * load balancing. | |
4076 | * @sds: Statistics of the sched_domain whose imbalance is to be calculated. | |
4077 | * @this_cpu: The cpu at whose sched_domain we're performing load-balance. | |
4078 | * @imbalance: Variable to store the imbalance. | |
4079 | */ | |
4080 | static inline void fix_small_imbalance(struct sd_lb_stats *sds, | |
4081 | int this_cpu, unsigned long *imbalance) | |
4082 | { | |
4083 | unsigned long tmp, pwr_now = 0, pwr_move = 0; | |
4084 | unsigned int imbn = 2; | |
dd5feea1 | 4085 | unsigned long scaled_busy_load_per_task; |
1e3c88bd PZ |
4086 | |
4087 | if (sds->this_nr_running) { | |
4088 | sds->this_load_per_task /= sds->this_nr_running; | |
4089 | if (sds->busiest_load_per_task > | |
4090 | sds->this_load_per_task) | |
4091 | imbn = 1; | |
4092 | } else | |
4093 | sds->this_load_per_task = | |
4094 | cpu_avg_load_per_task(this_cpu); | |
4095 | ||
dd5feea1 | 4096 | scaled_busy_load_per_task = sds->busiest_load_per_task |
1399fa78 | 4097 | * SCHED_POWER_SCALE; |
9c3f75cb | 4098 | scaled_busy_load_per_task /= sds->busiest->sgp->power; |
dd5feea1 SS |
4099 | |
4100 | if (sds->max_load - sds->this_load + scaled_busy_load_per_task >= | |
4101 | (scaled_busy_load_per_task * imbn)) { | |
1e3c88bd PZ |
4102 | *imbalance = sds->busiest_load_per_task; |
4103 | return; | |
4104 | } | |
4105 | ||
4106 | /* | |
4107 | * OK, we don't have enough imbalance to justify moving tasks, | |
4108 | * however we may be able to increase total CPU power used by | |
4109 | * moving them. | |
4110 | */ | |
4111 | ||
9c3f75cb | 4112 | pwr_now += sds->busiest->sgp->power * |
1e3c88bd | 4113 | min(sds->busiest_load_per_task, sds->max_load); |
9c3f75cb | 4114 | pwr_now += sds->this->sgp->power * |
1e3c88bd | 4115 | min(sds->this_load_per_task, sds->this_load); |
1399fa78 | 4116 | pwr_now /= SCHED_POWER_SCALE; |
1e3c88bd PZ |
4117 | |
4118 | /* Amount of load we'd subtract */ | |
1399fa78 | 4119 | tmp = (sds->busiest_load_per_task * SCHED_POWER_SCALE) / |
9c3f75cb | 4120 | sds->busiest->sgp->power; |
1e3c88bd | 4121 | if (sds->max_load > tmp) |
9c3f75cb | 4122 | pwr_move += sds->busiest->sgp->power * |
1e3c88bd PZ |
4123 | min(sds->busiest_load_per_task, sds->max_load - tmp); |
4124 | ||
4125 | /* Amount of load we'd add */ | |
9c3f75cb | 4126 | if (sds->max_load * sds->busiest->sgp->power < |
1399fa78 | 4127 | sds->busiest_load_per_task * SCHED_POWER_SCALE) |
9c3f75cb PZ |
4128 | tmp = (sds->max_load * sds->busiest->sgp->power) / |
4129 | sds->this->sgp->power; | |
1e3c88bd | 4130 | else |
1399fa78 | 4131 | tmp = (sds->busiest_load_per_task * SCHED_POWER_SCALE) / |
9c3f75cb PZ |
4132 | sds->this->sgp->power; |
4133 | pwr_move += sds->this->sgp->power * | |
1e3c88bd | 4134 | min(sds->this_load_per_task, sds->this_load + tmp); |
1399fa78 | 4135 | pwr_move /= SCHED_POWER_SCALE; |
1e3c88bd PZ |
4136 | |
4137 | /* Move if we gain throughput */ | |
4138 | if (pwr_move > pwr_now) | |
4139 | *imbalance = sds->busiest_load_per_task; | |
4140 | } | |
4141 | ||
4142 | /** | |
4143 | * calculate_imbalance - Calculate the amount of imbalance present within the | |
4144 | * groups of a given sched_domain during load balance. | |
4145 | * @sds: statistics of the sched_domain whose imbalance is to be calculated. | |
4146 | * @this_cpu: Cpu for which currently load balance is being performed. | |
4147 | * @imbalance: The variable to store the imbalance. | |
4148 | */ | |
4149 | static inline void calculate_imbalance(struct sd_lb_stats *sds, int this_cpu, | |
4150 | unsigned long *imbalance) | |
4151 | { | |
dd5feea1 SS |
4152 | unsigned long max_pull, load_above_capacity = ~0UL; |
4153 | ||
4154 | sds->busiest_load_per_task /= sds->busiest_nr_running; | |
4155 | if (sds->group_imb) { | |
4156 | sds->busiest_load_per_task = | |
4157 | min(sds->busiest_load_per_task, sds->avg_load); | |
4158 | } | |
4159 | ||
1e3c88bd PZ |
4160 | /* |
4161 | * In the presence of smp nice balancing, certain scenarios can have | |
4162 | * max load less than avg load(as we skip the groups at or below | |
4163 | * its cpu_power, while calculating max_load..) | |
4164 | */ | |
4165 | if (sds->max_load < sds->avg_load) { | |
4166 | *imbalance = 0; | |
4167 | return fix_small_imbalance(sds, this_cpu, imbalance); | |
4168 | } | |
4169 | ||
dd5feea1 SS |
4170 | if (!sds->group_imb) { |
4171 | /* | |
4172 | * Don't want to pull so many tasks that a group would go idle. | |
4173 | */ | |
4174 | load_above_capacity = (sds->busiest_nr_running - | |
4175 | sds->busiest_group_capacity); | |
4176 | ||
1399fa78 | 4177 | load_above_capacity *= (SCHED_LOAD_SCALE * SCHED_POWER_SCALE); |
dd5feea1 | 4178 | |
9c3f75cb | 4179 | load_above_capacity /= sds->busiest->sgp->power; |
dd5feea1 SS |
4180 | } |
4181 | ||
4182 | /* | |
4183 | * We're trying to get all the cpus to the average_load, so we don't | |
4184 | * want to push ourselves above the average load, nor do we wish to | |
4185 | * reduce the max loaded cpu below the average load. At the same time, | |
4186 | * we also don't want to reduce the group load below the group capacity | |
4187 | * (so that we can implement power-savings policies etc). Thus we look | |
4188 | * for the minimum possible imbalance. | |
4189 | * Be careful of negative numbers as they'll appear as very large values | |
4190 | * with unsigned longs. | |
4191 | */ | |
4192 | max_pull = min(sds->max_load - sds->avg_load, load_above_capacity); | |
1e3c88bd PZ |
4193 | |
4194 | /* How much load to actually move to equalise the imbalance */ | |
9c3f75cb PZ |
4195 | *imbalance = min(max_pull * sds->busiest->sgp->power, |
4196 | (sds->avg_load - sds->this_load) * sds->this->sgp->power) | |
1399fa78 | 4197 | / SCHED_POWER_SCALE; |
1e3c88bd PZ |
4198 | |
4199 | /* | |
4200 | * if *imbalance is less than the average load per runnable task | |
25985edc | 4201 | * there is no guarantee that any tasks will be moved so we'll have |
1e3c88bd PZ |
4202 | * a think about bumping its value to force at least one task to be |
4203 | * moved | |
4204 | */ | |
4205 | if (*imbalance < sds->busiest_load_per_task) | |
4206 | return fix_small_imbalance(sds, this_cpu, imbalance); | |
4207 | ||
4208 | } | |
fab47622 | 4209 | |
1e3c88bd PZ |
4210 | /******* find_busiest_group() helpers end here *********************/ |
4211 | ||
4212 | /** | |
4213 | * find_busiest_group - Returns the busiest group within the sched_domain | |
4214 | * if there is an imbalance. If there isn't an imbalance, and | |
4215 | * the user has opted for power-savings, it returns a group whose | |
4216 | * CPUs can be put to idle by rebalancing those tasks elsewhere, if | |
4217 | * such a group exists. | |
4218 | * | |
4219 | * Also calculates the amount of weighted load which should be moved | |
4220 | * to restore balance. | |
4221 | * | |
4222 | * @sd: The sched_domain whose busiest group is to be returned. | |
4223 | * @this_cpu: The cpu for which load balancing is currently being performed. | |
4224 | * @imbalance: Variable which stores amount of weighted load which should | |
4225 | * be moved to restore balance/put a group to idle. | |
4226 | * @idle: The idle status of this_cpu. | |
1e3c88bd PZ |
4227 | * @cpus: The set of CPUs under consideration for load-balancing. |
4228 | * @balance: Pointer to a variable indicating if this_cpu | |
4229 | * is the appropriate cpu to perform load balancing at this_level. | |
4230 | * | |
4231 | * Returns: - the busiest group if imbalance exists. | |
4232 | * - If no imbalance and user has opted for power-savings balance, | |
4233 | * return the least loaded group whose CPUs can be | |
4234 | * put to idle by rebalancing its tasks onto our group. | |
4235 | */ | |
4236 | static struct sched_group * | |
4237 | find_busiest_group(struct sched_domain *sd, int this_cpu, | |
4238 | unsigned long *imbalance, enum cpu_idle_type idle, | |
46e49b38 | 4239 | const struct cpumask *cpus, int *balance) |
1e3c88bd PZ |
4240 | { |
4241 | struct sd_lb_stats sds; | |
4242 | ||
4243 | memset(&sds, 0, sizeof(sds)); | |
4244 | ||
4245 | /* | |
4246 | * Compute the various statistics relavent for load balancing at | |
4247 | * this level. | |
4248 | */ | |
46e49b38 | 4249 | update_sd_lb_stats(sd, this_cpu, idle, cpus, balance, &sds); |
1e3c88bd | 4250 | |
cc57aa8f PZ |
4251 | /* |
4252 | * this_cpu is not the appropriate cpu to perform load balancing at | |
4253 | * this level. | |
1e3c88bd | 4254 | */ |
8f190fb3 | 4255 | if (!(*balance)) |
1e3c88bd PZ |
4256 | goto ret; |
4257 | ||
532cb4c4 MN |
4258 | if ((idle == CPU_IDLE || idle == CPU_NEWLY_IDLE) && |
4259 | check_asym_packing(sd, &sds, this_cpu, imbalance)) | |
4260 | return sds.busiest; | |
4261 | ||
cc57aa8f | 4262 | /* There is no busy sibling group to pull tasks from */ |
1e3c88bd PZ |
4263 | if (!sds.busiest || sds.busiest_nr_running == 0) |
4264 | goto out_balanced; | |
4265 | ||
1399fa78 | 4266 | sds.avg_load = (SCHED_POWER_SCALE * sds.total_load) / sds.total_pwr; |
b0432d8f | 4267 | |
866ab43e PZ |
4268 | /* |
4269 | * If the busiest group is imbalanced the below checks don't | |
4270 | * work because they assumes all things are equal, which typically | |
4271 | * isn't true due to cpus_allowed constraints and the like. | |
4272 | */ | |
4273 | if (sds.group_imb) | |
4274 | goto force_balance; | |
4275 | ||
cc57aa8f | 4276 | /* SD_BALANCE_NEWIDLE trumps SMP nice when underutilized */ |
fab47622 NR |
4277 | if (idle == CPU_NEWLY_IDLE && sds.this_has_capacity && |
4278 | !sds.busiest_has_capacity) | |
4279 | goto force_balance; | |
4280 | ||
cc57aa8f PZ |
4281 | /* |
4282 | * If the local group is more busy than the selected busiest group | |
4283 | * don't try and pull any tasks. | |
4284 | */ | |
1e3c88bd PZ |
4285 | if (sds.this_load >= sds.max_load) |
4286 | goto out_balanced; | |
4287 | ||
cc57aa8f PZ |
4288 | /* |
4289 | * Don't pull any tasks if this group is already above the domain | |
4290 | * average load. | |
4291 | */ | |
1e3c88bd PZ |
4292 | if (sds.this_load >= sds.avg_load) |
4293 | goto out_balanced; | |
4294 | ||
c186fafe | 4295 | if (idle == CPU_IDLE) { |
aae6d3dd SS |
4296 | /* |
4297 | * This cpu is idle. If the busiest group load doesn't | |
4298 | * have more tasks than the number of available cpu's and | |
4299 | * there is no imbalance between this and busiest group | |
4300 | * wrt to idle cpu's, it is balanced. | |
4301 | */ | |
c186fafe | 4302 | if ((sds.this_idle_cpus <= sds.busiest_idle_cpus + 1) && |
aae6d3dd SS |
4303 | sds.busiest_nr_running <= sds.busiest_group_weight) |
4304 | goto out_balanced; | |
c186fafe PZ |
4305 | } else { |
4306 | /* | |
4307 | * In the CPU_NEWLY_IDLE, CPU_NOT_IDLE cases, use | |
4308 | * imbalance_pct to be conservative. | |
4309 | */ | |
4310 | if (100 * sds.max_load <= sd->imbalance_pct * sds.this_load) | |
4311 | goto out_balanced; | |
aae6d3dd | 4312 | } |
1e3c88bd | 4313 | |
fab47622 | 4314 | force_balance: |
1e3c88bd PZ |
4315 | /* Looks like there is an imbalance. Compute it */ |
4316 | calculate_imbalance(&sds, this_cpu, imbalance); | |
4317 | return sds.busiest; | |
4318 | ||
4319 | out_balanced: | |
4320 | /* | |
4321 | * There is no obvious imbalance. But check if we can do some balancing | |
4322 | * to save power. | |
4323 | */ | |
4324 | if (check_power_save_busiest_group(&sds, this_cpu, imbalance)) | |
4325 | return sds.busiest; | |
4326 | ret: | |
4327 | *imbalance = 0; | |
4328 | return NULL; | |
4329 | } | |
4330 | ||
4331 | /* | |
4332 | * find_busiest_queue - find the busiest runqueue among the cpus in group. | |
4333 | */ | |
4334 | static struct rq * | |
9d5efe05 SV |
4335 | find_busiest_queue(struct sched_domain *sd, struct sched_group *group, |
4336 | enum cpu_idle_type idle, unsigned long imbalance, | |
4337 | const struct cpumask *cpus) | |
1e3c88bd PZ |
4338 | { |
4339 | struct rq *busiest = NULL, *rq; | |
4340 | unsigned long max_load = 0; | |
4341 | int i; | |
4342 | ||
4343 | for_each_cpu(i, sched_group_cpus(group)) { | |
4344 | unsigned long power = power_of(i); | |
1399fa78 NR |
4345 | unsigned long capacity = DIV_ROUND_CLOSEST(power, |
4346 | SCHED_POWER_SCALE); | |
1e3c88bd PZ |
4347 | unsigned long wl; |
4348 | ||
9d5efe05 SV |
4349 | if (!capacity) |
4350 | capacity = fix_small_capacity(sd, group); | |
4351 | ||
1e3c88bd PZ |
4352 | if (!cpumask_test_cpu(i, cpus)) |
4353 | continue; | |
4354 | ||
4355 | rq = cpu_rq(i); | |
6e40f5bb | 4356 | wl = weighted_cpuload(i); |
1e3c88bd | 4357 | |
6e40f5bb TG |
4358 | /* |
4359 | * When comparing with imbalance, use weighted_cpuload() | |
4360 | * which is not scaled with the cpu power. | |
4361 | */ | |
1e3c88bd PZ |
4362 | if (capacity && rq->nr_running == 1 && wl > imbalance) |
4363 | continue; | |
4364 | ||
6e40f5bb TG |
4365 | /* |
4366 | * For the load comparisons with the other cpu's, consider | |
4367 | * the weighted_cpuload() scaled with the cpu power, so that | |
4368 | * the load can be moved away from the cpu that is potentially | |
4369 | * running at a lower capacity. | |
4370 | */ | |
1399fa78 | 4371 | wl = (wl * SCHED_POWER_SCALE) / power; |
6e40f5bb | 4372 | |
1e3c88bd PZ |
4373 | if (wl > max_load) { |
4374 | max_load = wl; | |
4375 | busiest = rq; | |
4376 | } | |
4377 | } | |
4378 | ||
4379 | return busiest; | |
4380 | } | |
4381 | ||
4382 | /* | |
4383 | * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but | |
4384 | * so long as it is large enough. | |
4385 | */ | |
4386 | #define MAX_PINNED_INTERVAL 512 | |
4387 | ||
4388 | /* Working cpumask for load_balance and load_balance_newidle. */ | |
029632fb | 4389 | DEFINE_PER_CPU(cpumask_var_t, load_balance_tmpmask); |
1e3c88bd | 4390 | |
46e49b38 | 4391 | static int need_active_balance(struct sched_domain *sd, int idle, |
532cb4c4 | 4392 | int busiest_cpu, int this_cpu) |
1af3ed3d PZ |
4393 | { |
4394 | if (idle == CPU_NEWLY_IDLE) { | |
532cb4c4 MN |
4395 | |
4396 | /* | |
4397 | * ASYM_PACKING needs to force migrate tasks from busy but | |
4398 | * higher numbered CPUs in order to pack all tasks in the | |
4399 | * lowest numbered CPUs. | |
4400 | */ | |
4401 | if ((sd->flags & SD_ASYM_PACKING) && busiest_cpu > this_cpu) | |
4402 | return 1; | |
4403 | ||
1af3ed3d PZ |
4404 | /* |
4405 | * The only task running in a non-idle cpu can be moved to this | |
4406 | * cpu in an attempt to completely freeup the other CPU | |
4407 | * package. | |
4408 | * | |
4409 | * The package power saving logic comes from | |
4410 | * find_busiest_group(). If there are no imbalance, then | |
4411 | * f_b_g() will return NULL. However when sched_mc={1,2} then | |
4412 | * f_b_g() will select a group from which a running task may be | |
4413 | * pulled to this cpu in order to make the other package idle. | |
4414 | * If there is no opportunity to make a package idle and if | |
4415 | * there are no imbalance, then f_b_g() will return NULL and no | |
4416 | * action will be taken in load_balance_newidle(). | |
4417 | * | |
4418 | * Under normal task pull operation due to imbalance, there | |
4419 | * will be more than one task in the source run queue and | |
4420 | * move_tasks() will succeed. ld_moved will be true and this | |
4421 | * active balance code will not be triggered. | |
4422 | */ | |
1af3ed3d PZ |
4423 | if (sched_mc_power_savings < POWERSAVINGS_BALANCE_WAKEUP) |
4424 | return 0; | |
4425 | } | |
4426 | ||
4427 | return unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2); | |
4428 | } | |
4429 | ||
969c7921 TH |
4430 | static int active_load_balance_cpu_stop(void *data); |
4431 | ||
1e3c88bd PZ |
4432 | /* |
4433 | * Check this_cpu to ensure it is balanced within domain. Attempt to move | |
4434 | * tasks if there is an imbalance. | |
4435 | */ | |
4436 | static int load_balance(int this_cpu, struct rq *this_rq, | |
4437 | struct sched_domain *sd, enum cpu_idle_type idle, | |
4438 | int *balance) | |
4439 | { | |
46e49b38 | 4440 | int ld_moved, all_pinned = 0, active_balance = 0; |
1e3c88bd PZ |
4441 | struct sched_group *group; |
4442 | unsigned long imbalance; | |
4443 | struct rq *busiest; | |
4444 | unsigned long flags; | |
4445 | struct cpumask *cpus = __get_cpu_var(load_balance_tmpmask); | |
4446 | ||
4447 | cpumask_copy(cpus, cpu_active_mask); | |
4448 | ||
1e3c88bd PZ |
4449 | schedstat_inc(sd, lb_count[idle]); |
4450 | ||
4451 | redo: | |
46e49b38 | 4452 | group = find_busiest_group(sd, this_cpu, &imbalance, idle, |
1e3c88bd PZ |
4453 | cpus, balance); |
4454 | ||
4455 | if (*balance == 0) | |
4456 | goto out_balanced; | |
4457 | ||
4458 | if (!group) { | |
4459 | schedstat_inc(sd, lb_nobusyg[idle]); | |
4460 | goto out_balanced; | |
4461 | } | |
4462 | ||
9d5efe05 | 4463 | busiest = find_busiest_queue(sd, group, idle, imbalance, cpus); |
1e3c88bd PZ |
4464 | if (!busiest) { |
4465 | schedstat_inc(sd, lb_nobusyq[idle]); | |
4466 | goto out_balanced; | |
4467 | } | |
4468 | ||
4469 | BUG_ON(busiest == this_rq); | |
4470 | ||
4471 | schedstat_add(sd, lb_imbalance[idle], imbalance); | |
4472 | ||
4473 | ld_moved = 0; | |
4474 | if (busiest->nr_running > 1) { | |
4475 | /* | |
4476 | * Attempt to move tasks. If find_busiest_group has found | |
4477 | * an imbalance but busiest->nr_running <= 1, the group is | |
4478 | * still unbalanced. ld_moved simply stays zero, so it is | |
4479 | * correctly treated as an imbalance. | |
4480 | */ | |
b30aef17 | 4481 | all_pinned = 1; |
1e3c88bd PZ |
4482 | local_irq_save(flags); |
4483 | double_rq_lock(this_rq, busiest); | |
4484 | ld_moved = move_tasks(this_rq, this_cpu, busiest, | |
4485 | imbalance, sd, idle, &all_pinned); | |
4486 | double_rq_unlock(this_rq, busiest); | |
4487 | local_irq_restore(flags); | |
4488 | ||
4489 | /* | |
4490 | * some other cpu did the load balance for us. | |
4491 | */ | |
4492 | if (ld_moved && this_cpu != smp_processor_id()) | |
4493 | resched_cpu(this_cpu); | |
4494 | ||
4495 | /* All tasks on this runqueue were pinned by CPU affinity */ | |
4496 | if (unlikely(all_pinned)) { | |
4497 | cpumask_clear_cpu(cpu_of(busiest), cpus); | |
4498 | if (!cpumask_empty(cpus)) | |
4499 | goto redo; | |
4500 | goto out_balanced; | |
4501 | } | |
4502 | } | |
4503 | ||
4504 | if (!ld_moved) { | |
4505 | schedstat_inc(sd, lb_failed[idle]); | |
58b26c4c VP |
4506 | /* |
4507 | * Increment the failure counter only on periodic balance. | |
4508 | * We do not want newidle balance, which can be very | |
4509 | * frequent, pollute the failure counter causing | |
4510 | * excessive cache_hot migrations and active balances. | |
4511 | */ | |
4512 | if (idle != CPU_NEWLY_IDLE) | |
4513 | sd->nr_balance_failed++; | |
1e3c88bd | 4514 | |
46e49b38 | 4515 | if (need_active_balance(sd, idle, cpu_of(busiest), this_cpu)) { |
1e3c88bd PZ |
4516 | raw_spin_lock_irqsave(&busiest->lock, flags); |
4517 | ||
969c7921 TH |
4518 | /* don't kick the active_load_balance_cpu_stop, |
4519 | * if the curr task on busiest cpu can't be | |
4520 | * moved to this_cpu | |
1e3c88bd PZ |
4521 | */ |
4522 | if (!cpumask_test_cpu(this_cpu, | |
fa17b507 | 4523 | tsk_cpus_allowed(busiest->curr))) { |
1e3c88bd PZ |
4524 | raw_spin_unlock_irqrestore(&busiest->lock, |
4525 | flags); | |
4526 | all_pinned = 1; | |
4527 | goto out_one_pinned; | |
4528 | } | |
4529 | ||
969c7921 TH |
4530 | /* |
4531 | * ->active_balance synchronizes accesses to | |
4532 | * ->active_balance_work. Once set, it's cleared | |
4533 | * only after active load balance is finished. | |
4534 | */ | |
1e3c88bd PZ |
4535 | if (!busiest->active_balance) { |
4536 | busiest->active_balance = 1; | |
4537 | busiest->push_cpu = this_cpu; | |
4538 | active_balance = 1; | |
4539 | } | |
4540 | raw_spin_unlock_irqrestore(&busiest->lock, flags); | |
969c7921 | 4541 | |
1e3c88bd | 4542 | if (active_balance) |
969c7921 TH |
4543 | stop_one_cpu_nowait(cpu_of(busiest), |
4544 | active_load_balance_cpu_stop, busiest, | |
4545 | &busiest->active_balance_work); | |
1e3c88bd PZ |
4546 | |
4547 | /* | |
4548 | * We've kicked active balancing, reset the failure | |
4549 | * counter. | |
4550 | */ | |
4551 | sd->nr_balance_failed = sd->cache_nice_tries+1; | |
4552 | } | |
4553 | } else | |
4554 | sd->nr_balance_failed = 0; | |
4555 | ||
4556 | if (likely(!active_balance)) { | |
4557 | /* We were unbalanced, so reset the balancing interval */ | |
4558 | sd->balance_interval = sd->min_interval; | |
4559 | } else { | |
4560 | /* | |
4561 | * If we've begun active balancing, start to back off. This | |
4562 | * case may not be covered by the all_pinned logic if there | |
4563 | * is only 1 task on the busy runqueue (because we don't call | |
4564 | * move_tasks). | |
4565 | */ | |
4566 | if (sd->balance_interval < sd->max_interval) | |
4567 | sd->balance_interval *= 2; | |
4568 | } | |
4569 | ||
1e3c88bd PZ |
4570 | goto out; |
4571 | ||
4572 | out_balanced: | |
4573 | schedstat_inc(sd, lb_balanced[idle]); | |
4574 | ||
4575 | sd->nr_balance_failed = 0; | |
4576 | ||
4577 | out_one_pinned: | |
4578 | /* tune up the balancing interval */ | |
4579 | if ((all_pinned && sd->balance_interval < MAX_PINNED_INTERVAL) || | |
4580 | (sd->balance_interval < sd->max_interval)) | |
4581 | sd->balance_interval *= 2; | |
4582 | ||
46e49b38 | 4583 | ld_moved = 0; |
1e3c88bd | 4584 | out: |
1e3c88bd PZ |
4585 | return ld_moved; |
4586 | } | |
4587 | ||
1e3c88bd PZ |
4588 | /* |
4589 | * idle_balance is called by schedule() if this_cpu is about to become | |
4590 | * idle. Attempts to pull tasks from other CPUs. | |
4591 | */ | |
029632fb | 4592 | void idle_balance(int this_cpu, struct rq *this_rq) |
1e3c88bd PZ |
4593 | { |
4594 | struct sched_domain *sd; | |
4595 | int pulled_task = 0; | |
4596 | unsigned long next_balance = jiffies + HZ; | |
4597 | ||
4598 | this_rq->idle_stamp = this_rq->clock; | |
4599 | ||
4600 | if (this_rq->avg_idle < sysctl_sched_migration_cost) | |
4601 | return; | |
4602 | ||
f492e12e PZ |
4603 | /* |
4604 | * Drop the rq->lock, but keep IRQ/preempt disabled. | |
4605 | */ | |
4606 | raw_spin_unlock(&this_rq->lock); | |
4607 | ||
c66eaf61 | 4608 | update_shares(this_cpu); |
dce840a0 | 4609 | rcu_read_lock(); |
1e3c88bd PZ |
4610 | for_each_domain(this_cpu, sd) { |
4611 | unsigned long interval; | |
f492e12e | 4612 | int balance = 1; |
1e3c88bd PZ |
4613 | |
4614 | if (!(sd->flags & SD_LOAD_BALANCE)) | |
4615 | continue; | |
4616 | ||
f492e12e | 4617 | if (sd->flags & SD_BALANCE_NEWIDLE) { |
1e3c88bd | 4618 | /* If we've pulled tasks over stop searching: */ |
f492e12e PZ |
4619 | pulled_task = load_balance(this_cpu, this_rq, |
4620 | sd, CPU_NEWLY_IDLE, &balance); | |
4621 | } | |
1e3c88bd PZ |
4622 | |
4623 | interval = msecs_to_jiffies(sd->balance_interval); | |
4624 | if (time_after(next_balance, sd->last_balance + interval)) | |
4625 | next_balance = sd->last_balance + interval; | |
d5ad140b NR |
4626 | if (pulled_task) { |
4627 | this_rq->idle_stamp = 0; | |
1e3c88bd | 4628 | break; |
d5ad140b | 4629 | } |
1e3c88bd | 4630 | } |
dce840a0 | 4631 | rcu_read_unlock(); |
f492e12e PZ |
4632 | |
4633 | raw_spin_lock(&this_rq->lock); | |
4634 | ||
1e3c88bd PZ |
4635 | if (pulled_task || time_after(jiffies, this_rq->next_balance)) { |
4636 | /* | |
4637 | * We are going idle. next_balance may be set based on | |
4638 | * a busy processor. So reset next_balance. | |
4639 | */ | |
4640 | this_rq->next_balance = next_balance; | |
4641 | } | |
4642 | } | |
4643 | ||
4644 | /* | |
969c7921 TH |
4645 | * active_load_balance_cpu_stop is run by cpu stopper. It pushes |
4646 | * running tasks off the busiest CPU onto idle CPUs. It requires at | |
4647 | * least 1 task to be running on each physical CPU where possible, and | |
4648 | * avoids physical / logical imbalances. | |
1e3c88bd | 4649 | */ |
969c7921 | 4650 | static int active_load_balance_cpu_stop(void *data) |
1e3c88bd | 4651 | { |
969c7921 TH |
4652 | struct rq *busiest_rq = data; |
4653 | int busiest_cpu = cpu_of(busiest_rq); | |
1e3c88bd | 4654 | int target_cpu = busiest_rq->push_cpu; |
969c7921 | 4655 | struct rq *target_rq = cpu_rq(target_cpu); |
1e3c88bd | 4656 | struct sched_domain *sd; |
969c7921 TH |
4657 | |
4658 | raw_spin_lock_irq(&busiest_rq->lock); | |
4659 | ||
4660 | /* make sure the requested cpu hasn't gone down in the meantime */ | |
4661 | if (unlikely(busiest_cpu != smp_processor_id() || | |
4662 | !busiest_rq->active_balance)) | |
4663 | goto out_unlock; | |
1e3c88bd PZ |
4664 | |
4665 | /* Is there any task to move? */ | |
4666 | if (busiest_rq->nr_running <= 1) | |
969c7921 | 4667 | goto out_unlock; |
1e3c88bd PZ |
4668 | |
4669 | /* | |
4670 | * This condition is "impossible", if it occurs | |
4671 | * we need to fix it. Originally reported by | |
4672 | * Bjorn Helgaas on a 128-cpu setup. | |
4673 | */ | |
4674 | BUG_ON(busiest_rq == target_rq); | |
4675 | ||
4676 | /* move a task from busiest_rq to target_rq */ | |
4677 | double_lock_balance(busiest_rq, target_rq); | |
1e3c88bd PZ |
4678 | |
4679 | /* Search for an sd spanning us and the target CPU. */ | |
dce840a0 | 4680 | rcu_read_lock(); |
1e3c88bd PZ |
4681 | for_each_domain(target_cpu, sd) { |
4682 | if ((sd->flags & SD_LOAD_BALANCE) && | |
4683 | cpumask_test_cpu(busiest_cpu, sched_domain_span(sd))) | |
4684 | break; | |
4685 | } | |
4686 | ||
4687 | if (likely(sd)) { | |
4688 | schedstat_inc(sd, alb_count); | |
4689 | ||
4690 | if (move_one_task(target_rq, target_cpu, busiest_rq, | |
4691 | sd, CPU_IDLE)) | |
4692 | schedstat_inc(sd, alb_pushed); | |
4693 | else | |
4694 | schedstat_inc(sd, alb_failed); | |
4695 | } | |
dce840a0 | 4696 | rcu_read_unlock(); |
1e3c88bd | 4697 | double_unlock_balance(busiest_rq, target_rq); |
969c7921 TH |
4698 | out_unlock: |
4699 | busiest_rq->active_balance = 0; | |
4700 | raw_spin_unlock_irq(&busiest_rq->lock); | |
4701 | return 0; | |
1e3c88bd PZ |
4702 | } |
4703 | ||
4704 | #ifdef CONFIG_NO_HZ | |
83cd4fe2 VP |
4705 | /* |
4706 | * idle load balancing details | |
4707 | * - One of the idle CPUs nominates itself as idle load_balancer, while | |
4708 | * entering idle. | |
4709 | * - This idle load balancer CPU will also go into tickless mode when | |
4710 | * it is idle, just like all other idle CPUs | |
4711 | * - When one of the busy CPUs notice that there may be an idle rebalancing | |
4712 | * needed, they will kick the idle load balancer, which then does idle | |
4713 | * load balancing for all the idle CPUs. | |
4714 | */ | |
1e3c88bd PZ |
4715 | static struct { |
4716 | atomic_t load_balancer; | |
83cd4fe2 VP |
4717 | atomic_t first_pick_cpu; |
4718 | atomic_t second_pick_cpu; | |
4719 | cpumask_var_t idle_cpus_mask; | |
4720 | cpumask_var_t grp_idle_mask; | |
4721 | unsigned long next_balance; /* in jiffy units */ | |
4722 | } nohz ____cacheline_aligned; | |
1e3c88bd PZ |
4723 | |
4724 | int get_nohz_load_balancer(void) | |
4725 | { | |
4726 | return atomic_read(&nohz.load_balancer); | |
4727 | } | |
4728 | ||
4729 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) | |
4730 | /** | |
4731 | * lowest_flag_domain - Return lowest sched_domain containing flag. | |
4732 | * @cpu: The cpu whose lowest level of sched domain is to | |
4733 | * be returned. | |
4734 | * @flag: The flag to check for the lowest sched_domain | |
4735 | * for the given cpu. | |
4736 | * | |
4737 | * Returns the lowest sched_domain of a cpu which contains the given flag. | |
4738 | */ | |
4739 | static inline struct sched_domain *lowest_flag_domain(int cpu, int flag) | |
4740 | { | |
4741 | struct sched_domain *sd; | |
4742 | ||
4743 | for_each_domain(cpu, sd) | |
08354716 | 4744 | if (sd->flags & flag) |
1e3c88bd PZ |
4745 | break; |
4746 | ||
4747 | return sd; | |
4748 | } | |
4749 | ||
4750 | /** | |
4751 | * for_each_flag_domain - Iterates over sched_domains containing the flag. | |
4752 | * @cpu: The cpu whose domains we're iterating over. | |
4753 | * @sd: variable holding the value of the power_savings_sd | |
4754 | * for cpu. | |
4755 | * @flag: The flag to filter the sched_domains to be iterated. | |
4756 | * | |
4757 | * Iterates over all the scheduler domains for a given cpu that has the 'flag' | |
4758 | * set, starting from the lowest sched_domain to the highest. | |
4759 | */ | |
4760 | #define for_each_flag_domain(cpu, sd, flag) \ | |
4761 | for (sd = lowest_flag_domain(cpu, flag); \ | |
4762 | (sd && (sd->flags & flag)); sd = sd->parent) | |
4763 | ||
4764 | /** | |
4765 | * is_semi_idle_group - Checks if the given sched_group is semi-idle. | |
4766 | * @ilb_group: group to be checked for semi-idleness | |
4767 | * | |
4768 | * Returns: 1 if the group is semi-idle. 0 otherwise. | |
4769 | * | |
4770 | * We define a sched_group to be semi idle if it has atleast one idle-CPU | |
4771 | * and atleast one non-idle CPU. This helper function checks if the given | |
4772 | * sched_group is semi-idle or not. | |
4773 | */ | |
4774 | static inline int is_semi_idle_group(struct sched_group *ilb_group) | |
4775 | { | |
83cd4fe2 | 4776 | cpumask_and(nohz.grp_idle_mask, nohz.idle_cpus_mask, |
1e3c88bd PZ |
4777 | sched_group_cpus(ilb_group)); |
4778 | ||
4779 | /* | |
4780 | * A sched_group is semi-idle when it has atleast one busy cpu | |
4781 | * and atleast one idle cpu. | |
4782 | */ | |
83cd4fe2 | 4783 | if (cpumask_empty(nohz.grp_idle_mask)) |
1e3c88bd PZ |
4784 | return 0; |
4785 | ||
83cd4fe2 | 4786 | if (cpumask_equal(nohz.grp_idle_mask, sched_group_cpus(ilb_group))) |
1e3c88bd PZ |
4787 | return 0; |
4788 | ||
4789 | return 1; | |
4790 | } | |
4791 | /** | |
4792 | * find_new_ilb - Finds the optimum idle load balancer for nomination. | |
4793 | * @cpu: The cpu which is nominating a new idle_load_balancer. | |
4794 | * | |
4795 | * Returns: Returns the id of the idle load balancer if it exists, | |
4796 | * Else, returns >= nr_cpu_ids. | |
4797 | * | |
4798 | * This algorithm picks the idle load balancer such that it belongs to a | |
4799 | * semi-idle powersavings sched_domain. The idea is to try and avoid | |
4800 | * completely idle packages/cores just for the purpose of idle load balancing | |
4801 | * when there are other idle cpu's which are better suited for that job. | |
4802 | */ | |
4803 | static int find_new_ilb(int cpu) | |
4804 | { | |
4805 | struct sched_domain *sd; | |
4806 | struct sched_group *ilb_group; | |
dce840a0 | 4807 | int ilb = nr_cpu_ids; |
1e3c88bd PZ |
4808 | |
4809 | /* | |
4810 | * Have idle load balancer selection from semi-idle packages only | |
4811 | * when power-aware load balancing is enabled | |
4812 | */ | |
4813 | if (!(sched_smt_power_savings || sched_mc_power_savings)) | |
4814 | goto out_done; | |
4815 | ||
4816 | /* | |
4817 | * Optimize for the case when we have no idle CPUs or only one | |
4818 | * idle CPU. Don't walk the sched_domain hierarchy in such cases | |
4819 | */ | |
83cd4fe2 | 4820 | if (cpumask_weight(nohz.idle_cpus_mask) < 2) |
1e3c88bd PZ |
4821 | goto out_done; |
4822 | ||
dce840a0 | 4823 | rcu_read_lock(); |
1e3c88bd PZ |
4824 | for_each_flag_domain(cpu, sd, SD_POWERSAVINGS_BALANCE) { |
4825 | ilb_group = sd->groups; | |
4826 | ||
4827 | do { | |
dce840a0 PZ |
4828 | if (is_semi_idle_group(ilb_group)) { |
4829 | ilb = cpumask_first(nohz.grp_idle_mask); | |
4830 | goto unlock; | |
4831 | } | |
1e3c88bd PZ |
4832 | |
4833 | ilb_group = ilb_group->next; | |
4834 | ||
4835 | } while (ilb_group != sd->groups); | |
4836 | } | |
dce840a0 PZ |
4837 | unlock: |
4838 | rcu_read_unlock(); | |
1e3c88bd PZ |
4839 | |
4840 | out_done: | |
dce840a0 | 4841 | return ilb; |
1e3c88bd PZ |
4842 | } |
4843 | #else /* (CONFIG_SCHED_MC || CONFIG_SCHED_SMT) */ | |
4844 | static inline int find_new_ilb(int call_cpu) | |
4845 | { | |
83cd4fe2 | 4846 | return nr_cpu_ids; |
1e3c88bd PZ |
4847 | } |
4848 | #endif | |
4849 | ||
83cd4fe2 VP |
4850 | /* |
4851 | * Kick a CPU to do the nohz balancing, if it is time for it. We pick the | |
4852 | * nohz_load_balancer CPU (if there is one) otherwise fallback to any idle | |
4853 | * CPU (if there is one). | |
4854 | */ | |
4855 | static void nohz_balancer_kick(int cpu) | |
4856 | { | |
4857 | int ilb_cpu; | |
4858 | ||
4859 | nohz.next_balance++; | |
4860 | ||
4861 | ilb_cpu = get_nohz_load_balancer(); | |
4862 | ||
4863 | if (ilb_cpu >= nr_cpu_ids) { | |
4864 | ilb_cpu = cpumask_first(nohz.idle_cpus_mask); | |
4865 | if (ilb_cpu >= nr_cpu_ids) | |
4866 | return; | |
4867 | } | |
4868 | ||
4869 | if (!cpu_rq(ilb_cpu)->nohz_balance_kick) { | |
83cd4fe2 | 4870 | cpu_rq(ilb_cpu)->nohz_balance_kick = 1; |
ca38062e SS |
4871 | |
4872 | smp_mb(); | |
4873 | /* | |
4874 | * Use smp_send_reschedule() instead of resched_cpu(). | |
4875 | * This way we generate a sched IPI on the target cpu which | |
4876 | * is idle. And the softirq performing nohz idle load balance | |
4877 | * will be run before returning from the IPI. | |
4878 | */ | |
4879 | smp_send_reschedule(ilb_cpu); | |
83cd4fe2 VP |
4880 | } |
4881 | return; | |
4882 | } | |
4883 | ||
1e3c88bd PZ |
4884 | /* |
4885 | * This routine will try to nominate the ilb (idle load balancing) | |
4886 | * owner among the cpus whose ticks are stopped. ilb owner will do the idle | |
83cd4fe2 | 4887 | * load balancing on behalf of all those cpus. |
1e3c88bd | 4888 | * |
83cd4fe2 VP |
4889 | * When the ilb owner becomes busy, we will not have new ilb owner until some |
4890 | * idle CPU wakes up and goes back to idle or some busy CPU tries to kick | |
4891 | * idle load balancing by kicking one of the idle CPUs. | |
1e3c88bd | 4892 | * |
83cd4fe2 VP |
4893 | * Ticks are stopped for the ilb owner as well, with busy CPU kicking this |
4894 | * ilb owner CPU in future (when there is a need for idle load balancing on | |
4895 | * behalf of all idle CPUs). | |
1e3c88bd | 4896 | */ |
83cd4fe2 | 4897 | void select_nohz_load_balancer(int stop_tick) |
1e3c88bd PZ |
4898 | { |
4899 | int cpu = smp_processor_id(); | |
4900 | ||
4901 | if (stop_tick) { | |
1e3c88bd PZ |
4902 | if (!cpu_active(cpu)) { |
4903 | if (atomic_read(&nohz.load_balancer) != cpu) | |
83cd4fe2 | 4904 | return; |
1e3c88bd PZ |
4905 | |
4906 | /* | |
4907 | * If we are going offline and still the leader, | |
4908 | * give up! | |
4909 | */ | |
83cd4fe2 VP |
4910 | if (atomic_cmpxchg(&nohz.load_balancer, cpu, |
4911 | nr_cpu_ids) != cpu) | |
1e3c88bd PZ |
4912 | BUG(); |
4913 | ||
83cd4fe2 | 4914 | return; |
1e3c88bd PZ |
4915 | } |
4916 | ||
83cd4fe2 | 4917 | cpumask_set_cpu(cpu, nohz.idle_cpus_mask); |
1e3c88bd | 4918 | |
83cd4fe2 VP |
4919 | if (atomic_read(&nohz.first_pick_cpu) == cpu) |
4920 | atomic_cmpxchg(&nohz.first_pick_cpu, cpu, nr_cpu_ids); | |
4921 | if (atomic_read(&nohz.second_pick_cpu) == cpu) | |
4922 | atomic_cmpxchg(&nohz.second_pick_cpu, cpu, nr_cpu_ids); | |
1e3c88bd | 4923 | |
83cd4fe2 | 4924 | if (atomic_read(&nohz.load_balancer) >= nr_cpu_ids) { |
1e3c88bd PZ |
4925 | int new_ilb; |
4926 | ||
83cd4fe2 VP |
4927 | /* make me the ilb owner */ |
4928 | if (atomic_cmpxchg(&nohz.load_balancer, nr_cpu_ids, | |
4929 | cpu) != nr_cpu_ids) | |
4930 | return; | |
4931 | ||
1e3c88bd PZ |
4932 | /* |
4933 | * Check to see if there is a more power-efficient | |
4934 | * ilb. | |
4935 | */ | |
4936 | new_ilb = find_new_ilb(cpu); | |
4937 | if (new_ilb < nr_cpu_ids && new_ilb != cpu) { | |
83cd4fe2 | 4938 | atomic_set(&nohz.load_balancer, nr_cpu_ids); |
1e3c88bd | 4939 | resched_cpu(new_ilb); |
83cd4fe2 | 4940 | return; |
1e3c88bd | 4941 | } |
83cd4fe2 | 4942 | return; |
1e3c88bd PZ |
4943 | } |
4944 | } else { | |
83cd4fe2 VP |
4945 | if (!cpumask_test_cpu(cpu, nohz.idle_cpus_mask)) |
4946 | return; | |
1e3c88bd | 4947 | |
83cd4fe2 | 4948 | cpumask_clear_cpu(cpu, nohz.idle_cpus_mask); |
1e3c88bd PZ |
4949 | |
4950 | if (atomic_read(&nohz.load_balancer) == cpu) | |
83cd4fe2 VP |
4951 | if (atomic_cmpxchg(&nohz.load_balancer, cpu, |
4952 | nr_cpu_ids) != cpu) | |
1e3c88bd PZ |
4953 | BUG(); |
4954 | } | |
83cd4fe2 | 4955 | return; |
1e3c88bd PZ |
4956 | } |
4957 | #endif | |
4958 | ||
4959 | static DEFINE_SPINLOCK(balancing); | |
4960 | ||
49c022e6 PZ |
4961 | static unsigned long __read_mostly max_load_balance_interval = HZ/10; |
4962 | ||
4963 | /* | |
4964 | * Scale the max load_balance interval with the number of CPUs in the system. | |
4965 | * This trades load-balance latency on larger machines for less cross talk. | |
4966 | */ | |
029632fb | 4967 | void update_max_interval(void) |
49c022e6 PZ |
4968 | { |
4969 | max_load_balance_interval = HZ*num_online_cpus()/10; | |
4970 | } | |
4971 | ||
1e3c88bd PZ |
4972 | /* |
4973 | * It checks each scheduling domain to see if it is due to be balanced, | |
4974 | * and initiates a balancing operation if so. | |
4975 | * | |
4976 | * Balancing parameters are set up in arch_init_sched_domains. | |
4977 | */ | |
4978 | static void rebalance_domains(int cpu, enum cpu_idle_type idle) | |
4979 | { | |
4980 | int balance = 1; | |
4981 | struct rq *rq = cpu_rq(cpu); | |
4982 | unsigned long interval; | |
4983 | struct sched_domain *sd; | |
4984 | /* Earliest time when we have to do rebalance again */ | |
4985 | unsigned long next_balance = jiffies + 60*HZ; | |
4986 | int update_next_balance = 0; | |
4987 | int need_serialize; | |
4988 | ||
2069dd75 PZ |
4989 | update_shares(cpu); |
4990 | ||
dce840a0 | 4991 | rcu_read_lock(); |
1e3c88bd PZ |
4992 | for_each_domain(cpu, sd) { |
4993 | if (!(sd->flags & SD_LOAD_BALANCE)) | |
4994 | continue; | |
4995 | ||
4996 | interval = sd->balance_interval; | |
4997 | if (idle != CPU_IDLE) | |
4998 | interval *= sd->busy_factor; | |
4999 | ||
5000 | /* scale ms to jiffies */ | |
5001 | interval = msecs_to_jiffies(interval); | |
49c022e6 | 5002 | interval = clamp(interval, 1UL, max_load_balance_interval); |
1e3c88bd PZ |
5003 | |
5004 | need_serialize = sd->flags & SD_SERIALIZE; | |
5005 | ||
5006 | if (need_serialize) { | |
5007 | if (!spin_trylock(&balancing)) | |
5008 | goto out; | |
5009 | } | |
5010 | ||
5011 | if (time_after_eq(jiffies, sd->last_balance + interval)) { | |
5012 | if (load_balance(cpu, rq, sd, idle, &balance)) { | |
5013 | /* | |
5014 | * We've pulled tasks over so either we're no | |
c186fafe | 5015 | * longer idle. |
1e3c88bd PZ |
5016 | */ |
5017 | idle = CPU_NOT_IDLE; | |
5018 | } | |
5019 | sd->last_balance = jiffies; | |
5020 | } | |
5021 | if (need_serialize) | |
5022 | spin_unlock(&balancing); | |
5023 | out: | |
5024 | if (time_after(next_balance, sd->last_balance + interval)) { | |
5025 | next_balance = sd->last_balance + interval; | |
5026 | update_next_balance = 1; | |
5027 | } | |
5028 | ||
5029 | /* | |
5030 | * Stop the load balance at this level. There is another | |
5031 | * CPU in our sched group which is doing load balancing more | |
5032 | * actively. | |
5033 | */ | |
5034 | if (!balance) | |
5035 | break; | |
5036 | } | |
dce840a0 | 5037 | rcu_read_unlock(); |
1e3c88bd PZ |
5038 | |
5039 | /* | |
5040 | * next_balance will be updated only when there is a need. | |
5041 | * When the cpu is attached to null domain for ex, it will not be | |
5042 | * updated. | |
5043 | */ | |
5044 | if (likely(update_next_balance)) | |
5045 | rq->next_balance = next_balance; | |
5046 | } | |
5047 | ||
83cd4fe2 | 5048 | #ifdef CONFIG_NO_HZ |
1e3c88bd | 5049 | /* |
83cd4fe2 | 5050 | * In CONFIG_NO_HZ case, the idle balance kickee will do the |
1e3c88bd PZ |
5051 | * rebalancing for all the cpus for whom scheduler ticks are stopped. |
5052 | */ | |
83cd4fe2 VP |
5053 | static void nohz_idle_balance(int this_cpu, enum cpu_idle_type idle) |
5054 | { | |
5055 | struct rq *this_rq = cpu_rq(this_cpu); | |
5056 | struct rq *rq; | |
5057 | int balance_cpu; | |
5058 | ||
5059 | if (idle != CPU_IDLE || !this_rq->nohz_balance_kick) | |
5060 | return; | |
5061 | ||
5062 | for_each_cpu(balance_cpu, nohz.idle_cpus_mask) { | |
5063 | if (balance_cpu == this_cpu) | |
5064 | continue; | |
5065 | ||
5066 | /* | |
5067 | * If this cpu gets work to do, stop the load balancing | |
5068 | * work being done for other cpus. Next load | |
5069 | * balancing owner will pick it up. | |
5070 | */ | |
5071 | if (need_resched()) { | |
5072 | this_rq->nohz_balance_kick = 0; | |
5073 | break; | |
5074 | } | |
5075 | ||
5076 | raw_spin_lock_irq(&this_rq->lock); | |
5343bdb8 | 5077 | update_rq_clock(this_rq); |
83cd4fe2 VP |
5078 | update_cpu_load(this_rq); |
5079 | raw_spin_unlock_irq(&this_rq->lock); | |
5080 | ||
5081 | rebalance_domains(balance_cpu, CPU_IDLE); | |
5082 | ||
5083 | rq = cpu_rq(balance_cpu); | |
5084 | if (time_after(this_rq->next_balance, rq->next_balance)) | |
5085 | this_rq->next_balance = rq->next_balance; | |
5086 | } | |
5087 | nohz.next_balance = this_rq->next_balance; | |
5088 | this_rq->nohz_balance_kick = 0; | |
5089 | } | |
5090 | ||
5091 | /* | |
5092 | * Current heuristic for kicking the idle load balancer | |
5093 | * - first_pick_cpu is the one of the busy CPUs. It will kick | |
5094 | * idle load balancer when it has more than one process active. This | |
5095 | * eliminates the need for idle load balancing altogether when we have | |
5096 | * only one running process in the system (common case). | |
5097 | * - If there are more than one busy CPU, idle load balancer may have | |
5098 | * to run for active_load_balance to happen (i.e., two busy CPUs are | |
5099 | * SMT or core siblings and can run better if they move to different | |
5100 | * physical CPUs). So, second_pick_cpu is the second of the busy CPUs | |
5101 | * which will kick idle load balancer as soon as it has any load. | |
5102 | */ | |
5103 | static inline int nohz_kick_needed(struct rq *rq, int cpu) | |
5104 | { | |
5105 | unsigned long now = jiffies; | |
5106 | int ret; | |
5107 | int first_pick_cpu, second_pick_cpu; | |
5108 | ||
5109 | if (time_before(now, nohz.next_balance)) | |
5110 | return 0; | |
5111 | ||
6eb57e0d | 5112 | if (idle_cpu(cpu)) |
83cd4fe2 VP |
5113 | return 0; |
5114 | ||
5115 | first_pick_cpu = atomic_read(&nohz.first_pick_cpu); | |
5116 | second_pick_cpu = atomic_read(&nohz.second_pick_cpu); | |
5117 | ||
5118 | if (first_pick_cpu < nr_cpu_ids && first_pick_cpu != cpu && | |
5119 | second_pick_cpu < nr_cpu_ids && second_pick_cpu != cpu) | |
5120 | return 0; | |
5121 | ||
5122 | ret = atomic_cmpxchg(&nohz.first_pick_cpu, nr_cpu_ids, cpu); | |
5123 | if (ret == nr_cpu_ids || ret == cpu) { | |
5124 | atomic_cmpxchg(&nohz.second_pick_cpu, cpu, nr_cpu_ids); | |
5125 | if (rq->nr_running > 1) | |
5126 | return 1; | |
5127 | } else { | |
5128 | ret = atomic_cmpxchg(&nohz.second_pick_cpu, nr_cpu_ids, cpu); | |
5129 | if (ret == nr_cpu_ids || ret == cpu) { | |
5130 | if (rq->nr_running) | |
5131 | return 1; | |
5132 | } | |
5133 | } | |
5134 | return 0; | |
5135 | } | |
5136 | #else | |
5137 | static void nohz_idle_balance(int this_cpu, enum cpu_idle_type idle) { } | |
5138 | #endif | |
5139 | ||
5140 | /* | |
5141 | * run_rebalance_domains is triggered when needed from the scheduler tick. | |
5142 | * Also triggered for nohz idle balancing (with nohz_balancing_kick set). | |
5143 | */ | |
1e3c88bd PZ |
5144 | static void run_rebalance_domains(struct softirq_action *h) |
5145 | { | |
5146 | int this_cpu = smp_processor_id(); | |
5147 | struct rq *this_rq = cpu_rq(this_cpu); | |
6eb57e0d | 5148 | enum cpu_idle_type idle = this_rq->idle_balance ? |
1e3c88bd PZ |
5149 | CPU_IDLE : CPU_NOT_IDLE; |
5150 | ||
5151 | rebalance_domains(this_cpu, idle); | |
5152 | ||
1e3c88bd | 5153 | /* |
83cd4fe2 | 5154 | * If this cpu has a pending nohz_balance_kick, then do the |
1e3c88bd PZ |
5155 | * balancing on behalf of the other idle cpus whose ticks are |
5156 | * stopped. | |
5157 | */ | |
83cd4fe2 | 5158 | nohz_idle_balance(this_cpu, idle); |
1e3c88bd PZ |
5159 | } |
5160 | ||
5161 | static inline int on_null_domain(int cpu) | |
5162 | { | |
90a6501f | 5163 | return !rcu_dereference_sched(cpu_rq(cpu)->sd); |
1e3c88bd PZ |
5164 | } |
5165 | ||
5166 | /* | |
5167 | * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing. | |
1e3c88bd | 5168 | */ |
029632fb | 5169 | void trigger_load_balance(struct rq *rq, int cpu) |
1e3c88bd | 5170 | { |
1e3c88bd PZ |
5171 | /* Don't need to rebalance while attached to NULL domain */ |
5172 | if (time_after_eq(jiffies, rq->next_balance) && | |
5173 | likely(!on_null_domain(cpu))) | |
5174 | raise_softirq(SCHED_SOFTIRQ); | |
83cd4fe2 VP |
5175 | #ifdef CONFIG_NO_HZ |
5176 | else if (nohz_kick_needed(rq, cpu) && likely(!on_null_domain(cpu))) | |
5177 | nohz_balancer_kick(cpu); | |
5178 | #endif | |
1e3c88bd PZ |
5179 | } |
5180 | ||
0bcdcf28 CE |
5181 | static void rq_online_fair(struct rq *rq) |
5182 | { | |
5183 | update_sysctl(); | |
5184 | } | |
5185 | ||
5186 | static void rq_offline_fair(struct rq *rq) | |
5187 | { | |
5188 | update_sysctl(); | |
5189 | } | |
5190 | ||
55e12e5e | 5191 | #endif /* CONFIG_SMP */ |
e1d1484f | 5192 | |
bf0f6f24 IM |
5193 | /* |
5194 | * scheduler tick hitting a task of our scheduling class: | |
5195 | */ | |
8f4d37ec | 5196 | static void task_tick_fair(struct rq *rq, struct task_struct *curr, int queued) |
bf0f6f24 IM |
5197 | { |
5198 | struct cfs_rq *cfs_rq; | |
5199 | struct sched_entity *se = &curr->se; | |
5200 | ||
5201 | for_each_sched_entity(se) { | |
5202 | cfs_rq = cfs_rq_of(se); | |
8f4d37ec | 5203 | entity_tick(cfs_rq, se, queued); |
bf0f6f24 IM |
5204 | } |
5205 | } | |
5206 | ||
5207 | /* | |
cd29fe6f PZ |
5208 | * called on fork with the child task as argument from the parent's context |
5209 | * - child not yet on the tasklist | |
5210 | * - preemption disabled | |
bf0f6f24 | 5211 | */ |
cd29fe6f | 5212 | static void task_fork_fair(struct task_struct *p) |
bf0f6f24 | 5213 | { |
cd29fe6f | 5214 | struct cfs_rq *cfs_rq = task_cfs_rq(current); |
429d43bc | 5215 | struct sched_entity *se = &p->se, *curr = cfs_rq->curr; |
00bf7bfc | 5216 | int this_cpu = smp_processor_id(); |
cd29fe6f PZ |
5217 | struct rq *rq = this_rq(); |
5218 | unsigned long flags; | |
5219 | ||
05fa785c | 5220 | raw_spin_lock_irqsave(&rq->lock, flags); |
bf0f6f24 | 5221 | |
861d034e PZ |
5222 | update_rq_clock(rq); |
5223 | ||
b0a0f667 PM |
5224 | if (unlikely(task_cpu(p) != this_cpu)) { |
5225 | rcu_read_lock(); | |
cd29fe6f | 5226 | __set_task_cpu(p, this_cpu); |
b0a0f667 PM |
5227 | rcu_read_unlock(); |
5228 | } | |
bf0f6f24 | 5229 | |
7109c442 | 5230 | update_curr(cfs_rq); |
cd29fe6f | 5231 | |
b5d9d734 MG |
5232 | if (curr) |
5233 | se->vruntime = curr->vruntime; | |
aeb73b04 | 5234 | place_entity(cfs_rq, se, 1); |
4d78e7b6 | 5235 | |
cd29fe6f | 5236 | if (sysctl_sched_child_runs_first && curr && entity_before(curr, se)) { |
87fefa38 | 5237 | /* |
edcb60a3 IM |
5238 | * Upon rescheduling, sched_class::put_prev_task() will place |
5239 | * 'current' within the tree based on its new key value. | |
5240 | */ | |
4d78e7b6 | 5241 | swap(curr->vruntime, se->vruntime); |
aec0a514 | 5242 | resched_task(rq->curr); |
4d78e7b6 | 5243 | } |
bf0f6f24 | 5244 | |
88ec22d3 PZ |
5245 | se->vruntime -= cfs_rq->min_vruntime; |
5246 | ||
05fa785c | 5247 | raw_spin_unlock_irqrestore(&rq->lock, flags); |
bf0f6f24 IM |
5248 | } |
5249 | ||
cb469845 SR |
5250 | /* |
5251 | * Priority of the task has changed. Check to see if we preempt | |
5252 | * the current task. | |
5253 | */ | |
da7a735e PZ |
5254 | static void |
5255 | prio_changed_fair(struct rq *rq, struct task_struct *p, int oldprio) | |
cb469845 | 5256 | { |
da7a735e PZ |
5257 | if (!p->se.on_rq) |
5258 | return; | |
5259 | ||
cb469845 SR |
5260 | /* |
5261 | * Reschedule if we are currently running on this runqueue and | |
5262 | * our priority decreased, or if we are not currently running on | |
5263 | * this runqueue and our priority is higher than the current's | |
5264 | */ | |
da7a735e | 5265 | if (rq->curr == p) { |
cb469845 SR |
5266 | if (p->prio > oldprio) |
5267 | resched_task(rq->curr); | |
5268 | } else | |
15afe09b | 5269 | check_preempt_curr(rq, p, 0); |
cb469845 SR |
5270 | } |
5271 | ||
da7a735e PZ |
5272 | static void switched_from_fair(struct rq *rq, struct task_struct *p) |
5273 | { | |
5274 | struct sched_entity *se = &p->se; | |
5275 | struct cfs_rq *cfs_rq = cfs_rq_of(se); | |
5276 | ||
5277 | /* | |
5278 | * Ensure the task's vruntime is normalized, so that when its | |
5279 | * switched back to the fair class the enqueue_entity(.flags=0) will | |
5280 | * do the right thing. | |
5281 | * | |
5282 | * If it was on_rq, then the dequeue_entity(.flags=0) will already | |
5283 | * have normalized the vruntime, if it was !on_rq, then only when | |
5284 | * the task is sleeping will it still have non-normalized vruntime. | |
5285 | */ | |
5286 | if (!se->on_rq && p->state != TASK_RUNNING) { | |
5287 | /* | |
5288 | * Fix up our vruntime so that the current sleep doesn't | |
5289 | * cause 'unlimited' sleep bonus. | |
5290 | */ | |
5291 | place_entity(cfs_rq, se, 0); | |
5292 | se->vruntime -= cfs_rq->min_vruntime; | |
5293 | } | |
5294 | } | |
5295 | ||
cb469845 SR |
5296 | /* |
5297 | * We switched to the sched_fair class. | |
5298 | */ | |
da7a735e | 5299 | static void switched_to_fair(struct rq *rq, struct task_struct *p) |
cb469845 | 5300 | { |
da7a735e PZ |
5301 | if (!p->se.on_rq) |
5302 | return; | |
5303 | ||
cb469845 SR |
5304 | /* |
5305 | * We were most likely switched from sched_rt, so | |
5306 | * kick off the schedule if running, otherwise just see | |
5307 | * if we can still preempt the current task. | |
5308 | */ | |
da7a735e | 5309 | if (rq->curr == p) |
cb469845 SR |
5310 | resched_task(rq->curr); |
5311 | else | |
15afe09b | 5312 | check_preempt_curr(rq, p, 0); |
cb469845 SR |
5313 | } |
5314 | ||
83b699ed SV |
5315 | /* Account for a task changing its policy or group. |
5316 | * | |
5317 | * This routine is mostly called to set cfs_rq->curr field when a task | |
5318 | * migrates between groups/classes. | |
5319 | */ | |
5320 | static void set_curr_task_fair(struct rq *rq) | |
5321 | { | |
5322 | struct sched_entity *se = &rq->curr->se; | |
5323 | ||
ec12cb7f PT |
5324 | for_each_sched_entity(se) { |
5325 | struct cfs_rq *cfs_rq = cfs_rq_of(se); | |
5326 | ||
5327 | set_next_entity(cfs_rq, se); | |
5328 | /* ensure bandwidth has been allocated on our new cfs_rq */ | |
5329 | account_cfs_rq_runtime(cfs_rq, 0); | |
5330 | } | |
83b699ed SV |
5331 | } |
5332 | ||
029632fb PZ |
5333 | void init_cfs_rq(struct cfs_rq *cfs_rq) |
5334 | { | |
5335 | cfs_rq->tasks_timeline = RB_ROOT; | |
5336 | INIT_LIST_HEAD(&cfs_rq->tasks); | |
5337 | cfs_rq->min_vruntime = (u64)(-(1LL << 20)); | |
5338 | #ifndef CONFIG_64BIT | |
5339 | cfs_rq->min_vruntime_copy = cfs_rq->min_vruntime; | |
5340 | #endif | |
5341 | } | |
5342 | ||
810b3817 | 5343 | #ifdef CONFIG_FAIR_GROUP_SCHED |
b2b5ce02 | 5344 | static void task_move_group_fair(struct task_struct *p, int on_rq) |
810b3817 | 5345 | { |
b2b5ce02 PZ |
5346 | /* |
5347 | * If the task was not on the rq at the time of this cgroup movement | |
5348 | * it must have been asleep, sleeping tasks keep their ->vruntime | |
5349 | * absolute on their old rq until wakeup (needed for the fair sleeper | |
5350 | * bonus in place_entity()). | |
5351 | * | |
5352 | * If it was on the rq, we've just 'preempted' it, which does convert | |
5353 | * ->vruntime to a relative base. | |
5354 | * | |
5355 | * Make sure both cases convert their relative position when migrating | |
5356 | * to another cgroup's rq. This does somewhat interfere with the | |
5357 | * fair sleeper stuff for the first placement, but who cares. | |
5358 | */ | |
5359 | if (!on_rq) | |
5360 | p->se.vruntime -= cfs_rq_of(&p->se)->min_vruntime; | |
5361 | set_task_rq(p, task_cpu(p)); | |
88ec22d3 | 5362 | if (!on_rq) |
b2b5ce02 | 5363 | p->se.vruntime += cfs_rq_of(&p->se)->min_vruntime; |
810b3817 | 5364 | } |
029632fb PZ |
5365 | |
5366 | void free_fair_sched_group(struct task_group *tg) | |
5367 | { | |
5368 | int i; | |
5369 | ||
5370 | destroy_cfs_bandwidth(tg_cfs_bandwidth(tg)); | |
5371 | ||
5372 | for_each_possible_cpu(i) { | |
5373 | if (tg->cfs_rq) | |
5374 | kfree(tg->cfs_rq[i]); | |
5375 | if (tg->se) | |
5376 | kfree(tg->se[i]); | |
5377 | } | |
5378 | ||
5379 | kfree(tg->cfs_rq); | |
5380 | kfree(tg->se); | |
5381 | } | |
5382 | ||
5383 | int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent) | |
5384 | { | |
5385 | struct cfs_rq *cfs_rq; | |
5386 | struct sched_entity *se; | |
5387 | int i; | |
5388 | ||
5389 | tg->cfs_rq = kzalloc(sizeof(cfs_rq) * nr_cpu_ids, GFP_KERNEL); | |
5390 | if (!tg->cfs_rq) | |
5391 | goto err; | |
5392 | tg->se = kzalloc(sizeof(se) * nr_cpu_ids, GFP_KERNEL); | |
5393 | if (!tg->se) | |
5394 | goto err; | |
5395 | ||
5396 | tg->shares = NICE_0_LOAD; | |
5397 | ||
5398 | init_cfs_bandwidth(tg_cfs_bandwidth(tg)); | |
5399 | ||
5400 | for_each_possible_cpu(i) { | |
5401 | cfs_rq = kzalloc_node(sizeof(struct cfs_rq), | |
5402 | GFP_KERNEL, cpu_to_node(i)); | |
5403 | if (!cfs_rq) | |
5404 | goto err; | |
5405 | ||
5406 | se = kzalloc_node(sizeof(struct sched_entity), | |
5407 | GFP_KERNEL, cpu_to_node(i)); | |
5408 | if (!se) | |
5409 | goto err_free_rq; | |
5410 | ||
5411 | init_cfs_rq(cfs_rq); | |
5412 | init_tg_cfs_entry(tg, cfs_rq, se, i, parent->se[i]); | |
5413 | } | |
5414 | ||
5415 | return 1; | |
5416 | ||
5417 | err_free_rq: | |
5418 | kfree(cfs_rq); | |
5419 | err: | |
5420 | return 0; | |
5421 | } | |
5422 | ||
5423 | void unregister_fair_sched_group(struct task_group *tg, int cpu) | |
5424 | { | |
5425 | struct rq *rq = cpu_rq(cpu); | |
5426 | unsigned long flags; | |
5427 | ||
5428 | /* | |
5429 | * Only empty task groups can be destroyed; so we can speculatively | |
5430 | * check on_list without danger of it being re-added. | |
5431 | */ | |
5432 | if (!tg->cfs_rq[cpu]->on_list) | |
5433 | return; | |
5434 | ||
5435 | raw_spin_lock_irqsave(&rq->lock, flags); | |
5436 | list_del_leaf_cfs_rq(tg->cfs_rq[cpu]); | |
5437 | raw_spin_unlock_irqrestore(&rq->lock, flags); | |
5438 | } | |
5439 | ||
5440 | void init_tg_cfs_entry(struct task_group *tg, struct cfs_rq *cfs_rq, | |
5441 | struct sched_entity *se, int cpu, | |
5442 | struct sched_entity *parent) | |
5443 | { | |
5444 | struct rq *rq = cpu_rq(cpu); | |
5445 | ||
5446 | cfs_rq->tg = tg; | |
5447 | cfs_rq->rq = rq; | |
5448 | #ifdef CONFIG_SMP | |
5449 | /* allow initial update_cfs_load() to truncate */ | |
5450 | cfs_rq->load_stamp = 1; | |
810b3817 | 5451 | #endif |
029632fb PZ |
5452 | init_cfs_rq_runtime(cfs_rq); |
5453 | ||
5454 | tg->cfs_rq[cpu] = cfs_rq; | |
5455 | tg->se[cpu] = se; | |
5456 | ||
5457 | /* se could be NULL for root_task_group */ | |
5458 | if (!se) | |
5459 | return; | |
5460 | ||
5461 | if (!parent) | |
5462 | se->cfs_rq = &rq->cfs; | |
5463 | else | |
5464 | se->cfs_rq = parent->my_q; | |
5465 | ||
5466 | se->my_q = cfs_rq; | |
5467 | update_load_set(&se->load, 0); | |
5468 | se->parent = parent; | |
5469 | } | |
5470 | ||
5471 | static DEFINE_MUTEX(shares_mutex); | |
5472 | ||
5473 | int sched_group_set_shares(struct task_group *tg, unsigned long shares) | |
5474 | { | |
5475 | int i; | |
5476 | unsigned long flags; | |
5477 | ||
5478 | /* | |
5479 | * We can't change the weight of the root cgroup. | |
5480 | */ | |
5481 | if (!tg->se[0]) | |
5482 | return -EINVAL; | |
5483 | ||
5484 | shares = clamp(shares, scale_load(MIN_SHARES), scale_load(MAX_SHARES)); | |
5485 | ||
5486 | mutex_lock(&shares_mutex); | |
5487 | if (tg->shares == shares) | |
5488 | goto done; | |
5489 | ||
5490 | tg->shares = shares; | |
5491 | for_each_possible_cpu(i) { | |
5492 | struct rq *rq = cpu_rq(i); | |
5493 | struct sched_entity *se; | |
5494 | ||
5495 | se = tg->se[i]; | |
5496 | /* Propagate contribution to hierarchy */ | |
5497 | raw_spin_lock_irqsave(&rq->lock, flags); | |
5498 | for_each_sched_entity(se) | |
5499 | update_cfs_shares(group_cfs_rq(se)); | |
5500 | raw_spin_unlock_irqrestore(&rq->lock, flags); | |
5501 | } | |
5502 | ||
5503 | done: | |
5504 | mutex_unlock(&shares_mutex); | |
5505 | return 0; | |
5506 | } | |
5507 | #else /* CONFIG_FAIR_GROUP_SCHED */ | |
5508 | ||
5509 | void free_fair_sched_group(struct task_group *tg) { } | |
5510 | ||
5511 | int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent) | |
5512 | { | |
5513 | return 1; | |
5514 | } | |
5515 | ||
5516 | void unregister_fair_sched_group(struct task_group *tg, int cpu) { } | |
5517 | ||
5518 | #endif /* CONFIG_FAIR_GROUP_SCHED */ | |
5519 | ||
810b3817 | 5520 | |
6d686f45 | 5521 | static unsigned int get_rr_interval_fair(struct rq *rq, struct task_struct *task) |
0d721cea PW |
5522 | { |
5523 | struct sched_entity *se = &task->se; | |
0d721cea PW |
5524 | unsigned int rr_interval = 0; |
5525 | ||
5526 | /* | |
5527 | * Time slice is 0 for SCHED_OTHER tasks that are on an otherwise | |
5528 | * idle runqueue: | |
5529 | */ | |
0d721cea PW |
5530 | if (rq->cfs.load.weight) |
5531 | rr_interval = NS_TO_JIFFIES(sched_slice(&rq->cfs, se)); | |
0d721cea PW |
5532 | |
5533 | return rr_interval; | |
5534 | } | |
5535 | ||
bf0f6f24 IM |
5536 | /* |
5537 | * All the scheduling class methods: | |
5538 | */ | |
029632fb | 5539 | const struct sched_class fair_sched_class = { |
5522d5d5 | 5540 | .next = &idle_sched_class, |
bf0f6f24 IM |
5541 | .enqueue_task = enqueue_task_fair, |
5542 | .dequeue_task = dequeue_task_fair, | |
5543 | .yield_task = yield_task_fair, | |
d95f4122 | 5544 | .yield_to_task = yield_to_task_fair, |
bf0f6f24 | 5545 | |
2e09bf55 | 5546 | .check_preempt_curr = check_preempt_wakeup, |
bf0f6f24 IM |
5547 | |
5548 | .pick_next_task = pick_next_task_fair, | |
5549 | .put_prev_task = put_prev_task_fair, | |
5550 | ||
681f3e68 | 5551 | #ifdef CONFIG_SMP |
4ce72a2c LZ |
5552 | .select_task_rq = select_task_rq_fair, |
5553 | ||
0bcdcf28 CE |
5554 | .rq_online = rq_online_fair, |
5555 | .rq_offline = rq_offline_fair, | |
88ec22d3 PZ |
5556 | |
5557 | .task_waking = task_waking_fair, | |
681f3e68 | 5558 | #endif |
bf0f6f24 | 5559 | |
83b699ed | 5560 | .set_curr_task = set_curr_task_fair, |
bf0f6f24 | 5561 | .task_tick = task_tick_fair, |
cd29fe6f | 5562 | .task_fork = task_fork_fair, |
cb469845 SR |
5563 | |
5564 | .prio_changed = prio_changed_fair, | |
da7a735e | 5565 | .switched_from = switched_from_fair, |
cb469845 | 5566 | .switched_to = switched_to_fair, |
810b3817 | 5567 | |
0d721cea PW |
5568 | .get_rr_interval = get_rr_interval_fair, |
5569 | ||
810b3817 | 5570 | #ifdef CONFIG_FAIR_GROUP_SCHED |
b2b5ce02 | 5571 | .task_move_group = task_move_group_fair, |
810b3817 | 5572 | #endif |
bf0f6f24 IM |
5573 | }; |
5574 | ||
5575 | #ifdef CONFIG_SCHED_DEBUG | |
029632fb | 5576 | void print_cfs_stats(struct seq_file *m, int cpu) |
bf0f6f24 | 5577 | { |
bf0f6f24 IM |
5578 | struct cfs_rq *cfs_rq; |
5579 | ||
5973e5b9 | 5580 | rcu_read_lock(); |
c3b64f1e | 5581 | for_each_leaf_cfs_rq(cpu_rq(cpu), cfs_rq) |
5cef9eca | 5582 | print_cfs_rq(m, cpu, cfs_rq); |
5973e5b9 | 5583 | rcu_read_unlock(); |
bf0f6f24 IM |
5584 | } |
5585 | #endif | |
029632fb PZ |
5586 | |
5587 | __init void init_sched_fair_class(void) | |
5588 | { | |
5589 | #ifdef CONFIG_SMP | |
5590 | open_softirq(SCHED_SOFTIRQ, run_rebalance_domains); | |
5591 | ||
5592 | #ifdef CONFIG_NO_HZ | |
5593 | zalloc_cpumask_var(&nohz.idle_cpus_mask, GFP_NOWAIT); | |
5594 | alloc_cpumask_var(&nohz.grp_idle_mask, GFP_NOWAIT); | |
5595 | atomic_set(&nohz.load_balancer, nr_cpu_ids); | |
5596 | atomic_set(&nohz.first_pick_cpu, nr_cpu_ids); | |
5597 | atomic_set(&nohz.second_pick_cpu, nr_cpu_ids); | |
5598 | #endif | |
5599 | #endif /* SMP */ | |
5600 | ||
5601 | } |