Commit | Line | Data |
---|---|---|
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> | |
cbee9f88 | 29 | #include <linux/mempolicy.h> |
e14808b4 | 30 | #include <linux/migrate.h> |
cbee9f88 | 31 | #include <linux/task_work.h> |
029632fb PZ |
32 | |
33 | #include <trace/events/sched.h> | |
34 | ||
35 | #include "sched.h" | |
9745512c | 36 | |
bf0f6f24 | 37 | /* |
21805085 | 38 | * Targeted preemption latency for CPU-bound tasks: |
864616ee | 39 | * (default: 6ms * (1 + ilog(ncpus)), units: nanoseconds) |
bf0f6f24 | 40 | * |
21805085 | 41 | * NOTE: this latency value is not the same as the concept of |
d274a4ce IM |
42 | * 'timeslice length' - timeslices in CFS are of variable length |
43 | * and have no persistent notion like in traditional, time-slice | |
44 | * based scheduling concepts. | |
bf0f6f24 | 45 | * |
d274a4ce IM |
46 | * (to see the precise effective timeslice length of your workload, |
47 | * run vmstat and monitor the context-switches (cs) field) | |
bf0f6f24 | 48 | */ |
21406928 MG |
49 | unsigned int sysctl_sched_latency = 6000000ULL; |
50 | unsigned int normalized_sysctl_sched_latency = 6000000ULL; | |
2bd8e6d4 | 51 | |
1983a922 CE |
52 | /* |
53 | * The initial- and re-scaling of tunables is configurable | |
54 | * (default SCHED_TUNABLESCALING_LOG = *(1+ilog(ncpus)) | |
55 | * | |
56 | * Options are: | |
57 | * SCHED_TUNABLESCALING_NONE - unscaled, always *1 | |
58 | * SCHED_TUNABLESCALING_LOG - scaled logarithmical, *1+ilog(ncpus) | |
59 | * SCHED_TUNABLESCALING_LINEAR - scaled linear, *ncpus | |
60 | */ | |
61 | enum sched_tunable_scaling sysctl_sched_tunable_scaling | |
62 | = SCHED_TUNABLESCALING_LOG; | |
63 | ||
2bd8e6d4 | 64 | /* |
b2be5e96 | 65 | * Minimal preemption granularity for CPU-bound tasks: |
864616ee | 66 | * (default: 0.75 msec * (1 + ilog(ncpus)), units: nanoseconds) |
2bd8e6d4 | 67 | */ |
0bf377bb IM |
68 | unsigned int sysctl_sched_min_granularity = 750000ULL; |
69 | unsigned int normalized_sysctl_sched_min_granularity = 750000ULL; | |
21805085 PZ |
70 | |
71 | /* | |
b2be5e96 PZ |
72 | * is kept at sysctl_sched_latency / sysctl_sched_min_granularity |
73 | */ | |
0bf377bb | 74 | static unsigned int sched_nr_latency = 8; |
b2be5e96 PZ |
75 | |
76 | /* | |
2bba22c5 | 77 | * After fork, child runs first. If set to 0 (default) then |
b2be5e96 | 78 | * parent will (try to) run first. |
21805085 | 79 | */ |
2bba22c5 | 80 | unsigned int sysctl_sched_child_runs_first __read_mostly; |
bf0f6f24 | 81 | |
bf0f6f24 IM |
82 | /* |
83 | * SCHED_OTHER wake-up granularity. | |
172e082a | 84 | * (default: 1 msec * (1 + ilog(ncpus)), units: nanoseconds) |
bf0f6f24 IM |
85 | * |
86 | * This option delays the preemption effects of decoupled workloads | |
87 | * and reduces their over-scheduling. Synchronous workloads will still | |
88 | * have immediate wakeup/sleep latencies. | |
89 | */ | |
172e082a | 90 | unsigned int sysctl_sched_wakeup_granularity = 1000000UL; |
0bcdcf28 | 91 | unsigned int normalized_sysctl_sched_wakeup_granularity = 1000000UL; |
bf0f6f24 | 92 | |
da84d961 IM |
93 | const_debug unsigned int sysctl_sched_migration_cost = 500000UL; |
94 | ||
a7a4f8a7 PT |
95 | /* |
96 | * The exponential sliding window over which load is averaged for shares | |
97 | * distribution. | |
98 | * (default: 10msec) | |
99 | */ | |
100 | unsigned int __read_mostly sysctl_sched_shares_window = 10000000UL; | |
101 | ||
ec12cb7f PT |
102 | #ifdef CONFIG_CFS_BANDWIDTH |
103 | /* | |
104 | * Amount of runtime to allocate from global (tg) to local (per-cfs_rq) pool | |
105 | * each time a cfs_rq requests quota. | |
106 | * | |
107 | * Note: in the case that the slice exceeds the runtime remaining (either due | |
108 | * to consumption or the quota being specified to be smaller than the slice) | |
109 | * we will always only issue the remaining available time. | |
110 | * | |
111 | * default: 5 msec, units: microseconds | |
112 | */ | |
113 | unsigned int sysctl_sched_cfs_bandwidth_slice = 5000UL; | |
114 | #endif | |
115 | ||
8527632d PG |
116 | static inline void update_load_add(struct load_weight *lw, unsigned long inc) |
117 | { | |
118 | lw->weight += inc; | |
119 | lw->inv_weight = 0; | |
120 | } | |
121 | ||
122 | static inline void update_load_sub(struct load_weight *lw, unsigned long dec) | |
123 | { | |
124 | lw->weight -= dec; | |
125 | lw->inv_weight = 0; | |
126 | } | |
127 | ||
128 | static inline void update_load_set(struct load_weight *lw, unsigned long w) | |
129 | { | |
130 | lw->weight = w; | |
131 | lw->inv_weight = 0; | |
132 | } | |
133 | ||
029632fb PZ |
134 | /* |
135 | * Increase the granularity value when there are more CPUs, | |
136 | * because with more CPUs the 'effective latency' as visible | |
137 | * to users decreases. But the relationship is not linear, | |
138 | * so pick a second-best guess by going with the log2 of the | |
139 | * number of CPUs. | |
140 | * | |
141 | * This idea comes from the SD scheduler of Con Kolivas: | |
142 | */ | |
143 | static int get_update_sysctl_factor(void) | |
144 | { | |
145 | unsigned int cpus = min_t(int, num_online_cpus(), 8); | |
146 | unsigned int factor; | |
147 | ||
148 | switch (sysctl_sched_tunable_scaling) { | |
149 | case SCHED_TUNABLESCALING_NONE: | |
150 | factor = 1; | |
151 | break; | |
152 | case SCHED_TUNABLESCALING_LINEAR: | |
153 | factor = cpus; | |
154 | break; | |
155 | case SCHED_TUNABLESCALING_LOG: | |
156 | default: | |
157 | factor = 1 + ilog2(cpus); | |
158 | break; | |
159 | } | |
160 | ||
161 | return factor; | |
162 | } | |
163 | ||
164 | static void update_sysctl(void) | |
165 | { | |
166 | unsigned int factor = get_update_sysctl_factor(); | |
167 | ||
168 | #define SET_SYSCTL(name) \ | |
169 | (sysctl_##name = (factor) * normalized_sysctl_##name) | |
170 | SET_SYSCTL(sched_min_granularity); | |
171 | SET_SYSCTL(sched_latency); | |
172 | SET_SYSCTL(sched_wakeup_granularity); | |
173 | #undef SET_SYSCTL | |
174 | } | |
175 | ||
176 | void sched_init_granularity(void) | |
177 | { | |
178 | update_sysctl(); | |
179 | } | |
180 | ||
9dbdb155 | 181 | #define WMULT_CONST (~0U) |
029632fb PZ |
182 | #define WMULT_SHIFT 32 |
183 | ||
9dbdb155 PZ |
184 | static void __update_inv_weight(struct load_weight *lw) |
185 | { | |
186 | unsigned long w; | |
187 | ||
188 | if (likely(lw->inv_weight)) | |
189 | return; | |
190 | ||
191 | w = scale_load_down(lw->weight); | |
192 | ||
193 | if (BITS_PER_LONG > 32 && unlikely(w >= WMULT_CONST)) | |
194 | lw->inv_weight = 1; | |
195 | else if (unlikely(!w)) | |
196 | lw->inv_weight = WMULT_CONST; | |
197 | else | |
198 | lw->inv_weight = WMULT_CONST / w; | |
199 | } | |
029632fb PZ |
200 | |
201 | /* | |
9dbdb155 PZ |
202 | * delta_exec * weight / lw.weight |
203 | * OR | |
204 | * (delta_exec * (weight * lw->inv_weight)) >> WMULT_SHIFT | |
205 | * | |
206 | * Either weight := NICE_0_LOAD and lw \e prio_to_wmult[], in which case | |
207 | * we're guaranteed shift stays positive because inv_weight is guaranteed to | |
208 | * fit 32 bits, and NICE_0_LOAD gives another 10 bits; therefore shift >= 22. | |
209 | * | |
210 | * Or, weight =< lw.weight (because lw.weight is the runqueue weight), thus | |
211 | * weight/lw.weight <= 1, and therefore our shift will also be positive. | |
029632fb | 212 | */ |
9dbdb155 | 213 | static u64 __calc_delta(u64 delta_exec, unsigned long weight, struct load_weight *lw) |
029632fb | 214 | { |
9dbdb155 PZ |
215 | u64 fact = scale_load_down(weight); |
216 | int shift = WMULT_SHIFT; | |
029632fb | 217 | |
9dbdb155 | 218 | __update_inv_weight(lw); |
029632fb | 219 | |
9dbdb155 PZ |
220 | if (unlikely(fact >> 32)) { |
221 | while (fact >> 32) { | |
222 | fact >>= 1; | |
223 | shift--; | |
224 | } | |
029632fb PZ |
225 | } |
226 | ||
9dbdb155 PZ |
227 | /* hint to use a 32x32->64 mul */ |
228 | fact = (u64)(u32)fact * lw->inv_weight; | |
029632fb | 229 | |
9dbdb155 PZ |
230 | while (fact >> 32) { |
231 | fact >>= 1; | |
232 | shift--; | |
233 | } | |
029632fb | 234 | |
9dbdb155 | 235 | return mul_u64_u32_shr(delta_exec, fact, shift); |
029632fb PZ |
236 | } |
237 | ||
238 | ||
239 | const struct sched_class fair_sched_class; | |
a4c2f00f | 240 | |
bf0f6f24 IM |
241 | /************************************************************** |
242 | * CFS operations on generic schedulable entities: | |
243 | */ | |
244 | ||
62160e3f | 245 | #ifdef CONFIG_FAIR_GROUP_SCHED |
bf0f6f24 | 246 | |
62160e3f | 247 | /* cpu runqueue to which this cfs_rq is attached */ |
bf0f6f24 IM |
248 | static inline struct rq *rq_of(struct cfs_rq *cfs_rq) |
249 | { | |
62160e3f | 250 | return cfs_rq->rq; |
bf0f6f24 IM |
251 | } |
252 | ||
62160e3f IM |
253 | /* An entity is a task if it doesn't "own" a runqueue */ |
254 | #define entity_is_task(se) (!se->my_q) | |
bf0f6f24 | 255 | |
8f48894f PZ |
256 | static inline struct task_struct *task_of(struct sched_entity *se) |
257 | { | |
258 | #ifdef CONFIG_SCHED_DEBUG | |
259 | WARN_ON_ONCE(!entity_is_task(se)); | |
260 | #endif | |
261 | return container_of(se, struct task_struct, se); | |
262 | } | |
263 | ||
b758149c PZ |
264 | /* Walk up scheduling entities hierarchy */ |
265 | #define for_each_sched_entity(se) \ | |
266 | for (; se; se = se->parent) | |
267 | ||
268 | static inline struct cfs_rq *task_cfs_rq(struct task_struct *p) | |
269 | { | |
270 | return p->se.cfs_rq; | |
271 | } | |
272 | ||
273 | /* runqueue on which this entity is (to be) queued */ | |
274 | static inline struct cfs_rq *cfs_rq_of(struct sched_entity *se) | |
275 | { | |
276 | return se->cfs_rq; | |
277 | } | |
278 | ||
279 | /* runqueue "owned" by this group */ | |
280 | static inline struct cfs_rq *group_cfs_rq(struct sched_entity *grp) | |
281 | { | |
282 | return grp->my_q; | |
283 | } | |
284 | ||
aff3e498 PT |
285 | static void update_cfs_rq_blocked_load(struct cfs_rq *cfs_rq, |
286 | int force_update); | |
9ee474f5 | 287 | |
3d4b47b4 PZ |
288 | static inline void list_add_leaf_cfs_rq(struct cfs_rq *cfs_rq) |
289 | { | |
290 | if (!cfs_rq->on_list) { | |
67e86250 PT |
291 | /* |
292 | * Ensure we either appear before our parent (if already | |
293 | * enqueued) or force our parent to appear after us when it is | |
294 | * enqueued. The fact that we always enqueue bottom-up | |
295 | * reduces this to two cases. | |
296 | */ | |
297 | if (cfs_rq->tg->parent && | |
298 | cfs_rq->tg->parent->cfs_rq[cpu_of(rq_of(cfs_rq))]->on_list) { | |
299 | list_add_rcu(&cfs_rq->leaf_cfs_rq_list, | |
300 | &rq_of(cfs_rq)->leaf_cfs_rq_list); | |
301 | } else { | |
302 | list_add_tail_rcu(&cfs_rq->leaf_cfs_rq_list, | |
3d4b47b4 | 303 | &rq_of(cfs_rq)->leaf_cfs_rq_list); |
67e86250 | 304 | } |
3d4b47b4 PZ |
305 | |
306 | cfs_rq->on_list = 1; | |
9ee474f5 | 307 | /* We should have no load, but we need to update last_decay. */ |
aff3e498 | 308 | update_cfs_rq_blocked_load(cfs_rq, 0); |
3d4b47b4 PZ |
309 | } |
310 | } | |
311 | ||
312 | static inline void list_del_leaf_cfs_rq(struct cfs_rq *cfs_rq) | |
313 | { | |
314 | if (cfs_rq->on_list) { | |
315 | list_del_rcu(&cfs_rq->leaf_cfs_rq_list); | |
316 | cfs_rq->on_list = 0; | |
317 | } | |
318 | } | |
319 | ||
b758149c PZ |
320 | /* Iterate thr' all leaf cfs_rq's on a runqueue */ |
321 | #define for_each_leaf_cfs_rq(rq, cfs_rq) \ | |
322 | list_for_each_entry_rcu(cfs_rq, &rq->leaf_cfs_rq_list, leaf_cfs_rq_list) | |
323 | ||
324 | /* Do the two (enqueued) entities belong to the same group ? */ | |
325 | static inline int | |
326 | is_same_group(struct sched_entity *se, struct sched_entity *pse) | |
327 | { | |
328 | if (se->cfs_rq == pse->cfs_rq) | |
329 | return 1; | |
330 | ||
331 | return 0; | |
332 | } | |
333 | ||
334 | static inline struct sched_entity *parent_entity(struct sched_entity *se) | |
335 | { | |
336 | return se->parent; | |
337 | } | |
338 | ||
464b7527 PZ |
339 | /* return depth at which a sched entity is present in the hierarchy */ |
340 | static inline int depth_se(struct sched_entity *se) | |
341 | { | |
342 | int depth = 0; | |
343 | ||
344 | for_each_sched_entity(se) | |
345 | depth++; | |
346 | ||
347 | return depth; | |
348 | } | |
349 | ||
350 | static void | |
351 | find_matching_se(struct sched_entity **se, struct sched_entity **pse) | |
352 | { | |
353 | int se_depth, pse_depth; | |
354 | ||
355 | /* | |
356 | * preemption test can be made between sibling entities who are in the | |
357 | * same cfs_rq i.e who have a common parent. Walk up the hierarchy of | |
358 | * both tasks until we find their ancestors who are siblings of common | |
359 | * parent. | |
360 | */ | |
361 | ||
362 | /* First walk up until both entities are at same depth */ | |
363 | se_depth = depth_se(*se); | |
364 | pse_depth = depth_se(*pse); | |
365 | ||
366 | while (se_depth > pse_depth) { | |
367 | se_depth--; | |
368 | *se = parent_entity(*se); | |
369 | } | |
370 | ||
371 | while (pse_depth > se_depth) { | |
372 | pse_depth--; | |
373 | *pse = parent_entity(*pse); | |
374 | } | |
375 | ||
376 | while (!is_same_group(*se, *pse)) { | |
377 | *se = parent_entity(*se); | |
378 | *pse = parent_entity(*pse); | |
379 | } | |
380 | } | |
381 | ||
8f48894f PZ |
382 | #else /* !CONFIG_FAIR_GROUP_SCHED */ |
383 | ||
384 | static inline struct task_struct *task_of(struct sched_entity *se) | |
385 | { | |
386 | return container_of(se, struct task_struct, se); | |
387 | } | |
bf0f6f24 | 388 | |
62160e3f IM |
389 | static inline struct rq *rq_of(struct cfs_rq *cfs_rq) |
390 | { | |
391 | return container_of(cfs_rq, struct rq, cfs); | |
bf0f6f24 IM |
392 | } |
393 | ||
394 | #define entity_is_task(se) 1 | |
395 | ||
b758149c PZ |
396 | #define for_each_sched_entity(se) \ |
397 | for (; se; se = NULL) | |
bf0f6f24 | 398 | |
b758149c | 399 | static inline struct cfs_rq *task_cfs_rq(struct task_struct *p) |
bf0f6f24 | 400 | { |
b758149c | 401 | return &task_rq(p)->cfs; |
bf0f6f24 IM |
402 | } |
403 | ||
b758149c PZ |
404 | static inline struct cfs_rq *cfs_rq_of(struct sched_entity *se) |
405 | { | |
406 | struct task_struct *p = task_of(se); | |
407 | struct rq *rq = task_rq(p); | |
408 | ||
409 | return &rq->cfs; | |
410 | } | |
411 | ||
412 | /* runqueue "owned" by this group */ | |
413 | static inline struct cfs_rq *group_cfs_rq(struct sched_entity *grp) | |
414 | { | |
415 | return NULL; | |
416 | } | |
417 | ||
3d4b47b4 PZ |
418 | static inline void list_add_leaf_cfs_rq(struct cfs_rq *cfs_rq) |
419 | { | |
420 | } | |
421 | ||
422 | static inline void list_del_leaf_cfs_rq(struct cfs_rq *cfs_rq) | |
423 | { | |
424 | } | |
425 | ||
b758149c PZ |
426 | #define for_each_leaf_cfs_rq(rq, cfs_rq) \ |
427 | for (cfs_rq = &rq->cfs; cfs_rq; cfs_rq = NULL) | |
428 | ||
429 | static inline int | |
430 | is_same_group(struct sched_entity *se, struct sched_entity *pse) | |
431 | { | |
432 | return 1; | |
433 | } | |
434 | ||
435 | static inline struct sched_entity *parent_entity(struct sched_entity *se) | |
436 | { | |
437 | return NULL; | |
438 | } | |
439 | ||
464b7527 PZ |
440 | static inline void |
441 | find_matching_se(struct sched_entity **se, struct sched_entity **pse) | |
442 | { | |
443 | } | |
444 | ||
b758149c PZ |
445 | #endif /* CONFIG_FAIR_GROUP_SCHED */ |
446 | ||
6c16a6dc | 447 | static __always_inline |
9dbdb155 | 448 | void account_cfs_rq_runtime(struct cfs_rq *cfs_rq, u64 delta_exec); |
bf0f6f24 IM |
449 | |
450 | /************************************************************** | |
451 | * Scheduling class tree data structure manipulation methods: | |
452 | */ | |
453 | ||
1bf08230 | 454 | static inline u64 max_vruntime(u64 max_vruntime, u64 vruntime) |
02e0431a | 455 | { |
1bf08230 | 456 | s64 delta = (s64)(vruntime - max_vruntime); |
368059a9 | 457 | if (delta > 0) |
1bf08230 | 458 | max_vruntime = vruntime; |
02e0431a | 459 | |
1bf08230 | 460 | return max_vruntime; |
02e0431a PZ |
461 | } |
462 | ||
0702e3eb | 463 | static inline u64 min_vruntime(u64 min_vruntime, u64 vruntime) |
b0ffd246 PZ |
464 | { |
465 | s64 delta = (s64)(vruntime - min_vruntime); | |
466 | if (delta < 0) | |
467 | min_vruntime = vruntime; | |
468 | ||
469 | return min_vruntime; | |
470 | } | |
471 | ||
54fdc581 FC |
472 | static inline int entity_before(struct sched_entity *a, |
473 | struct sched_entity *b) | |
474 | { | |
475 | return (s64)(a->vruntime - b->vruntime) < 0; | |
476 | } | |
477 | ||
1af5f730 PZ |
478 | static void update_min_vruntime(struct cfs_rq *cfs_rq) |
479 | { | |
480 | u64 vruntime = cfs_rq->min_vruntime; | |
481 | ||
482 | if (cfs_rq->curr) | |
483 | vruntime = cfs_rq->curr->vruntime; | |
484 | ||
485 | if (cfs_rq->rb_leftmost) { | |
486 | struct sched_entity *se = rb_entry(cfs_rq->rb_leftmost, | |
487 | struct sched_entity, | |
488 | run_node); | |
489 | ||
e17036da | 490 | if (!cfs_rq->curr) |
1af5f730 PZ |
491 | vruntime = se->vruntime; |
492 | else | |
493 | vruntime = min_vruntime(vruntime, se->vruntime); | |
494 | } | |
495 | ||
1bf08230 | 496 | /* ensure we never gain time by being placed backwards. */ |
1af5f730 | 497 | cfs_rq->min_vruntime = max_vruntime(cfs_rq->min_vruntime, vruntime); |
3fe1698b PZ |
498 | #ifndef CONFIG_64BIT |
499 | smp_wmb(); | |
500 | cfs_rq->min_vruntime_copy = cfs_rq->min_vruntime; | |
501 | #endif | |
1af5f730 PZ |
502 | } |
503 | ||
bf0f6f24 IM |
504 | /* |
505 | * Enqueue an entity into the rb-tree: | |
506 | */ | |
0702e3eb | 507 | static void __enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 IM |
508 | { |
509 | struct rb_node **link = &cfs_rq->tasks_timeline.rb_node; | |
510 | struct rb_node *parent = NULL; | |
511 | struct sched_entity *entry; | |
bf0f6f24 IM |
512 | int leftmost = 1; |
513 | ||
514 | /* | |
515 | * Find the right place in the rbtree: | |
516 | */ | |
517 | while (*link) { | |
518 | parent = *link; | |
519 | entry = rb_entry(parent, struct sched_entity, run_node); | |
520 | /* | |
521 | * We dont care about collisions. Nodes with | |
522 | * the same key stay together. | |
523 | */ | |
2bd2d6f2 | 524 | if (entity_before(se, entry)) { |
bf0f6f24 IM |
525 | link = &parent->rb_left; |
526 | } else { | |
527 | link = &parent->rb_right; | |
528 | leftmost = 0; | |
529 | } | |
530 | } | |
531 | ||
532 | /* | |
533 | * Maintain a cache of leftmost tree entries (it is frequently | |
534 | * used): | |
535 | */ | |
1af5f730 | 536 | if (leftmost) |
57cb499d | 537 | cfs_rq->rb_leftmost = &se->run_node; |
bf0f6f24 IM |
538 | |
539 | rb_link_node(&se->run_node, parent, link); | |
540 | rb_insert_color(&se->run_node, &cfs_rq->tasks_timeline); | |
bf0f6f24 IM |
541 | } |
542 | ||
0702e3eb | 543 | static void __dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 544 | { |
3fe69747 PZ |
545 | if (cfs_rq->rb_leftmost == &se->run_node) { |
546 | struct rb_node *next_node; | |
3fe69747 PZ |
547 | |
548 | next_node = rb_next(&se->run_node); | |
549 | cfs_rq->rb_leftmost = next_node; | |
3fe69747 | 550 | } |
e9acbff6 | 551 | |
bf0f6f24 | 552 | rb_erase(&se->run_node, &cfs_rq->tasks_timeline); |
bf0f6f24 IM |
553 | } |
554 | ||
029632fb | 555 | struct sched_entity *__pick_first_entity(struct cfs_rq *cfs_rq) |
bf0f6f24 | 556 | { |
f4b6755f PZ |
557 | struct rb_node *left = cfs_rq->rb_leftmost; |
558 | ||
559 | if (!left) | |
560 | return NULL; | |
561 | ||
562 | return rb_entry(left, struct sched_entity, run_node); | |
bf0f6f24 IM |
563 | } |
564 | ||
ac53db59 RR |
565 | static struct sched_entity *__pick_next_entity(struct sched_entity *se) |
566 | { | |
567 | struct rb_node *next = rb_next(&se->run_node); | |
568 | ||
569 | if (!next) | |
570 | return NULL; | |
571 | ||
572 | return rb_entry(next, struct sched_entity, run_node); | |
573 | } | |
574 | ||
575 | #ifdef CONFIG_SCHED_DEBUG | |
029632fb | 576 | struct sched_entity *__pick_last_entity(struct cfs_rq *cfs_rq) |
aeb73b04 | 577 | { |
7eee3e67 | 578 | struct rb_node *last = rb_last(&cfs_rq->tasks_timeline); |
aeb73b04 | 579 | |
70eee74b BS |
580 | if (!last) |
581 | return NULL; | |
7eee3e67 IM |
582 | |
583 | return rb_entry(last, struct sched_entity, run_node); | |
aeb73b04 PZ |
584 | } |
585 | ||
bf0f6f24 IM |
586 | /************************************************************** |
587 | * Scheduling class statistics methods: | |
588 | */ | |
589 | ||
acb4a848 | 590 | int sched_proc_update_handler(struct ctl_table *table, int write, |
8d65af78 | 591 | void __user *buffer, size_t *lenp, |
b2be5e96 PZ |
592 | loff_t *ppos) |
593 | { | |
8d65af78 | 594 | int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); |
acb4a848 | 595 | int factor = get_update_sysctl_factor(); |
b2be5e96 PZ |
596 | |
597 | if (ret || !write) | |
598 | return ret; | |
599 | ||
600 | sched_nr_latency = DIV_ROUND_UP(sysctl_sched_latency, | |
601 | sysctl_sched_min_granularity); | |
602 | ||
acb4a848 CE |
603 | #define WRT_SYSCTL(name) \ |
604 | (normalized_sysctl_##name = sysctl_##name / (factor)) | |
605 | WRT_SYSCTL(sched_min_granularity); | |
606 | WRT_SYSCTL(sched_latency); | |
607 | WRT_SYSCTL(sched_wakeup_granularity); | |
acb4a848 CE |
608 | #undef WRT_SYSCTL |
609 | ||
b2be5e96 PZ |
610 | return 0; |
611 | } | |
612 | #endif | |
647e7cac | 613 | |
a7be37ac | 614 | /* |
f9c0b095 | 615 | * delta /= w |
a7be37ac | 616 | */ |
9dbdb155 | 617 | static inline u64 calc_delta_fair(u64 delta, struct sched_entity *se) |
a7be37ac | 618 | { |
f9c0b095 | 619 | if (unlikely(se->load.weight != NICE_0_LOAD)) |
9dbdb155 | 620 | delta = __calc_delta(delta, NICE_0_LOAD, &se->load); |
a7be37ac PZ |
621 | |
622 | return delta; | |
623 | } | |
624 | ||
647e7cac IM |
625 | /* |
626 | * The idea is to set a period in which each task runs once. | |
627 | * | |
532b1858 | 628 | * When there are too many tasks (sched_nr_latency) we have to stretch |
647e7cac IM |
629 | * this period because otherwise the slices get too small. |
630 | * | |
631 | * p = (nr <= nl) ? l : l*nr/nl | |
632 | */ | |
4d78e7b6 PZ |
633 | static u64 __sched_period(unsigned long nr_running) |
634 | { | |
635 | u64 period = sysctl_sched_latency; | |
b2be5e96 | 636 | unsigned long nr_latency = sched_nr_latency; |
4d78e7b6 PZ |
637 | |
638 | if (unlikely(nr_running > nr_latency)) { | |
4bf0b771 | 639 | period = sysctl_sched_min_granularity; |
4d78e7b6 | 640 | period *= nr_running; |
4d78e7b6 PZ |
641 | } |
642 | ||
643 | return period; | |
644 | } | |
645 | ||
647e7cac IM |
646 | /* |
647 | * We calculate the wall-time slice from the period by taking a part | |
648 | * proportional to the weight. | |
649 | * | |
f9c0b095 | 650 | * s = p*P[w/rw] |
647e7cac | 651 | */ |
6d0f0ebd | 652 | static u64 sched_slice(struct cfs_rq *cfs_rq, struct sched_entity *se) |
21805085 | 653 | { |
0a582440 | 654 | u64 slice = __sched_period(cfs_rq->nr_running + !se->on_rq); |
f9c0b095 | 655 | |
0a582440 | 656 | for_each_sched_entity(se) { |
6272d68c | 657 | struct load_weight *load; |
3104bf03 | 658 | struct load_weight lw; |
6272d68c LM |
659 | |
660 | cfs_rq = cfs_rq_of(se); | |
661 | load = &cfs_rq->load; | |
f9c0b095 | 662 | |
0a582440 | 663 | if (unlikely(!se->on_rq)) { |
3104bf03 | 664 | lw = cfs_rq->load; |
0a582440 MG |
665 | |
666 | update_load_add(&lw, se->load.weight); | |
667 | load = &lw; | |
668 | } | |
9dbdb155 | 669 | slice = __calc_delta(slice, se->load.weight, load); |
0a582440 MG |
670 | } |
671 | return slice; | |
bf0f6f24 IM |
672 | } |
673 | ||
647e7cac | 674 | /* |
660cc00f | 675 | * We calculate the vruntime slice of a to-be-inserted task. |
647e7cac | 676 | * |
f9c0b095 | 677 | * vs = s/w |
647e7cac | 678 | */ |
f9c0b095 | 679 | static u64 sched_vslice(struct cfs_rq *cfs_rq, struct sched_entity *se) |
67e9fb2a | 680 | { |
f9c0b095 | 681 | return calc_delta_fair(sched_slice(cfs_rq, se), se); |
a7be37ac PZ |
682 | } |
683 | ||
a75cdaa9 | 684 | #ifdef CONFIG_SMP |
fb13c7ee MG |
685 | static unsigned long task_h_load(struct task_struct *p); |
686 | ||
a75cdaa9 AS |
687 | static inline void __update_task_entity_contrib(struct sched_entity *se); |
688 | ||
689 | /* Give new task start runnable values to heavy its load in infant time */ | |
690 | void init_task_runnable_average(struct task_struct *p) | |
691 | { | |
692 | u32 slice; | |
693 | ||
694 | p->se.avg.decay_count = 0; | |
695 | slice = sched_slice(task_cfs_rq(p), &p->se) >> 10; | |
696 | p->se.avg.runnable_avg_sum = slice; | |
697 | p->se.avg.runnable_avg_period = slice; | |
698 | __update_task_entity_contrib(&p->se); | |
699 | } | |
700 | #else | |
701 | void init_task_runnable_average(struct task_struct *p) | |
702 | { | |
703 | } | |
704 | #endif | |
705 | ||
bf0f6f24 | 706 | /* |
9dbdb155 | 707 | * Update the current task's runtime statistics. |
bf0f6f24 | 708 | */ |
b7cc0896 | 709 | static void update_curr(struct cfs_rq *cfs_rq) |
bf0f6f24 | 710 | { |
429d43bc | 711 | struct sched_entity *curr = cfs_rq->curr; |
78becc27 | 712 | u64 now = rq_clock_task(rq_of(cfs_rq)); |
9dbdb155 | 713 | u64 delta_exec; |
bf0f6f24 IM |
714 | |
715 | if (unlikely(!curr)) | |
716 | return; | |
717 | ||
9dbdb155 PZ |
718 | delta_exec = now - curr->exec_start; |
719 | if (unlikely((s64)delta_exec <= 0)) | |
34f28ecd | 720 | return; |
bf0f6f24 | 721 | |
8ebc91d9 | 722 | curr->exec_start = now; |
d842de87 | 723 | |
9dbdb155 PZ |
724 | schedstat_set(curr->statistics.exec_max, |
725 | max(delta_exec, curr->statistics.exec_max)); | |
726 | ||
727 | curr->sum_exec_runtime += delta_exec; | |
728 | schedstat_add(cfs_rq, exec_clock, delta_exec); | |
729 | ||
730 | curr->vruntime += calc_delta_fair(delta_exec, curr); | |
731 | update_min_vruntime(cfs_rq); | |
732 | ||
d842de87 SV |
733 | if (entity_is_task(curr)) { |
734 | struct task_struct *curtask = task_of(curr); | |
735 | ||
f977bb49 | 736 | trace_sched_stat_runtime(curtask, delta_exec, curr->vruntime); |
d842de87 | 737 | cpuacct_charge(curtask, delta_exec); |
f06febc9 | 738 | account_group_exec_runtime(curtask, delta_exec); |
d842de87 | 739 | } |
ec12cb7f PT |
740 | |
741 | account_cfs_rq_runtime(cfs_rq, delta_exec); | |
bf0f6f24 IM |
742 | } |
743 | ||
744 | static inline void | |
5870db5b | 745 | update_stats_wait_start(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 746 | { |
78becc27 | 747 | schedstat_set(se->statistics.wait_start, rq_clock(rq_of(cfs_rq))); |
bf0f6f24 IM |
748 | } |
749 | ||
bf0f6f24 IM |
750 | /* |
751 | * Task is being enqueued - update stats: | |
752 | */ | |
d2417e5a | 753 | static void update_stats_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 754 | { |
bf0f6f24 IM |
755 | /* |
756 | * Are we enqueueing a waiting task? (for current tasks | |
757 | * a dequeue/enqueue event is a NOP) | |
758 | */ | |
429d43bc | 759 | if (se != cfs_rq->curr) |
5870db5b | 760 | update_stats_wait_start(cfs_rq, se); |
bf0f6f24 IM |
761 | } |
762 | ||
bf0f6f24 | 763 | static void |
9ef0a961 | 764 | update_stats_wait_end(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 765 | { |
41acab88 | 766 | schedstat_set(se->statistics.wait_max, max(se->statistics.wait_max, |
78becc27 | 767 | rq_clock(rq_of(cfs_rq)) - se->statistics.wait_start)); |
41acab88 LDM |
768 | schedstat_set(se->statistics.wait_count, se->statistics.wait_count + 1); |
769 | schedstat_set(se->statistics.wait_sum, se->statistics.wait_sum + | |
78becc27 | 770 | rq_clock(rq_of(cfs_rq)) - se->statistics.wait_start); |
768d0c27 PZ |
771 | #ifdef CONFIG_SCHEDSTATS |
772 | if (entity_is_task(se)) { | |
773 | trace_sched_stat_wait(task_of(se), | |
78becc27 | 774 | rq_clock(rq_of(cfs_rq)) - se->statistics.wait_start); |
768d0c27 PZ |
775 | } |
776 | #endif | |
41acab88 | 777 | schedstat_set(se->statistics.wait_start, 0); |
bf0f6f24 IM |
778 | } |
779 | ||
780 | static inline void | |
19b6a2e3 | 781 | update_stats_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 782 | { |
bf0f6f24 IM |
783 | /* |
784 | * Mark the end of the wait period if dequeueing a | |
785 | * waiting task: | |
786 | */ | |
429d43bc | 787 | if (se != cfs_rq->curr) |
9ef0a961 | 788 | update_stats_wait_end(cfs_rq, se); |
bf0f6f24 IM |
789 | } |
790 | ||
791 | /* | |
792 | * We are picking a new current task - update its stats: | |
793 | */ | |
794 | static inline void | |
79303e9e | 795 | update_stats_curr_start(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 IM |
796 | { |
797 | /* | |
798 | * We are starting a new run period: | |
799 | */ | |
78becc27 | 800 | se->exec_start = rq_clock_task(rq_of(cfs_rq)); |
bf0f6f24 IM |
801 | } |
802 | ||
bf0f6f24 IM |
803 | /************************************************** |
804 | * Scheduling class queueing methods: | |
805 | */ | |
806 | ||
cbee9f88 PZ |
807 | #ifdef CONFIG_NUMA_BALANCING |
808 | /* | |
598f0ec0 MG |
809 | * Approximate time to scan a full NUMA task in ms. The task scan period is |
810 | * calculated based on the tasks virtual memory size and | |
811 | * numa_balancing_scan_size. | |
cbee9f88 | 812 | */ |
598f0ec0 MG |
813 | unsigned int sysctl_numa_balancing_scan_period_min = 1000; |
814 | unsigned int sysctl_numa_balancing_scan_period_max = 60000; | |
6e5fb223 PZ |
815 | |
816 | /* Portion of address space to scan in MB */ | |
817 | unsigned int sysctl_numa_balancing_scan_size = 256; | |
cbee9f88 | 818 | |
4b96a29b PZ |
819 | /* Scan @scan_size MB every @scan_period after an initial @scan_delay in ms */ |
820 | unsigned int sysctl_numa_balancing_scan_delay = 1000; | |
821 | ||
598f0ec0 MG |
822 | static unsigned int task_nr_scan_windows(struct task_struct *p) |
823 | { | |
824 | unsigned long rss = 0; | |
825 | unsigned long nr_scan_pages; | |
826 | ||
827 | /* | |
828 | * Calculations based on RSS as non-present and empty pages are skipped | |
829 | * by the PTE scanner and NUMA hinting faults should be trapped based | |
830 | * on resident pages | |
831 | */ | |
832 | nr_scan_pages = sysctl_numa_balancing_scan_size << (20 - PAGE_SHIFT); | |
833 | rss = get_mm_rss(p->mm); | |
834 | if (!rss) | |
835 | rss = nr_scan_pages; | |
836 | ||
837 | rss = round_up(rss, nr_scan_pages); | |
838 | return rss / nr_scan_pages; | |
839 | } | |
840 | ||
841 | /* For sanitys sake, never scan more PTEs than MAX_SCAN_WINDOW MB/sec. */ | |
842 | #define MAX_SCAN_WINDOW 2560 | |
843 | ||
844 | static unsigned int task_scan_min(struct task_struct *p) | |
845 | { | |
846 | unsigned int scan, floor; | |
847 | unsigned int windows = 1; | |
848 | ||
849 | if (sysctl_numa_balancing_scan_size < MAX_SCAN_WINDOW) | |
850 | windows = MAX_SCAN_WINDOW / sysctl_numa_balancing_scan_size; | |
851 | floor = 1000 / windows; | |
852 | ||
853 | scan = sysctl_numa_balancing_scan_period_min / task_nr_scan_windows(p); | |
854 | return max_t(unsigned int, floor, scan); | |
855 | } | |
856 | ||
857 | static unsigned int task_scan_max(struct task_struct *p) | |
858 | { | |
859 | unsigned int smin = task_scan_min(p); | |
860 | unsigned int smax; | |
861 | ||
862 | /* Watch for min being lower than max due to floor calculations */ | |
863 | smax = sysctl_numa_balancing_scan_period_max / task_nr_scan_windows(p); | |
864 | return max(smin, smax); | |
865 | } | |
866 | ||
0ec8aa00 PZ |
867 | static void account_numa_enqueue(struct rq *rq, struct task_struct *p) |
868 | { | |
869 | rq->nr_numa_running += (p->numa_preferred_nid != -1); | |
870 | rq->nr_preferred_running += (p->numa_preferred_nid == task_node(p)); | |
871 | } | |
872 | ||
873 | static void account_numa_dequeue(struct rq *rq, struct task_struct *p) | |
874 | { | |
875 | rq->nr_numa_running -= (p->numa_preferred_nid != -1); | |
876 | rq->nr_preferred_running -= (p->numa_preferred_nid == task_node(p)); | |
877 | } | |
878 | ||
8c8a743c PZ |
879 | struct numa_group { |
880 | atomic_t refcount; | |
881 | ||
882 | spinlock_t lock; /* nr_tasks, tasks */ | |
883 | int nr_tasks; | |
e29cf08b | 884 | pid_t gid; |
8c8a743c PZ |
885 | struct list_head task_list; |
886 | ||
887 | struct rcu_head rcu; | |
20e07dea | 888 | nodemask_t active_nodes; |
989348b5 | 889 | unsigned long total_faults; |
50ec8a40 | 890 | unsigned long *faults_cpu; |
989348b5 | 891 | unsigned long faults[0]; |
8c8a743c PZ |
892 | }; |
893 | ||
e29cf08b MG |
894 | pid_t task_numa_group_id(struct task_struct *p) |
895 | { | |
896 | return p->numa_group ? p->numa_group->gid : 0; | |
897 | } | |
898 | ||
ac8e895b MG |
899 | static inline int task_faults_idx(int nid, int priv) |
900 | { | |
901 | return 2 * nid + priv; | |
902 | } | |
903 | ||
904 | static inline unsigned long task_faults(struct task_struct *p, int nid) | |
905 | { | |
ff1df896 | 906 | if (!p->numa_faults_memory) |
ac8e895b MG |
907 | return 0; |
908 | ||
ff1df896 RR |
909 | return p->numa_faults_memory[task_faults_idx(nid, 0)] + |
910 | p->numa_faults_memory[task_faults_idx(nid, 1)]; | |
ac8e895b MG |
911 | } |
912 | ||
83e1d2cd MG |
913 | static inline unsigned long group_faults(struct task_struct *p, int nid) |
914 | { | |
915 | if (!p->numa_group) | |
916 | return 0; | |
917 | ||
82897b4f WL |
918 | return p->numa_group->faults[task_faults_idx(nid, 0)] + |
919 | p->numa_group->faults[task_faults_idx(nid, 1)]; | |
83e1d2cd MG |
920 | } |
921 | ||
20e07dea RR |
922 | static inline unsigned long group_faults_cpu(struct numa_group *group, int nid) |
923 | { | |
924 | return group->faults_cpu[task_faults_idx(nid, 0)] + | |
925 | group->faults_cpu[task_faults_idx(nid, 1)]; | |
926 | } | |
927 | ||
83e1d2cd MG |
928 | /* |
929 | * These return the fraction of accesses done by a particular task, or | |
930 | * task group, on a particular numa node. The group weight is given a | |
931 | * larger multiplier, in order to group tasks together that are almost | |
932 | * evenly spread out between numa nodes. | |
933 | */ | |
934 | static inline unsigned long task_weight(struct task_struct *p, int nid) | |
935 | { | |
936 | unsigned long total_faults; | |
937 | ||
ff1df896 | 938 | if (!p->numa_faults_memory) |
83e1d2cd MG |
939 | return 0; |
940 | ||
941 | total_faults = p->total_numa_faults; | |
942 | ||
943 | if (!total_faults) | |
944 | return 0; | |
945 | ||
946 | return 1000 * task_faults(p, nid) / total_faults; | |
947 | } | |
948 | ||
949 | static inline unsigned long group_weight(struct task_struct *p, int nid) | |
950 | { | |
989348b5 | 951 | if (!p->numa_group || !p->numa_group->total_faults) |
83e1d2cd MG |
952 | return 0; |
953 | ||
989348b5 | 954 | return 1000 * group_faults(p, nid) / p->numa_group->total_faults; |
83e1d2cd MG |
955 | } |
956 | ||
10f39042 RR |
957 | bool should_numa_migrate_memory(struct task_struct *p, struct page * page, |
958 | int src_nid, int dst_cpu) | |
959 | { | |
960 | struct numa_group *ng = p->numa_group; | |
961 | int dst_nid = cpu_to_node(dst_cpu); | |
962 | int last_cpupid, this_cpupid; | |
963 | ||
964 | this_cpupid = cpu_pid_to_cpupid(dst_cpu, current->pid); | |
965 | ||
966 | /* | |
967 | * Multi-stage node selection is used in conjunction with a periodic | |
968 | * migration fault to build a temporal task<->page relation. By using | |
969 | * a two-stage filter we remove short/unlikely relations. | |
970 | * | |
971 | * Using P(p) ~ n_p / n_t as per frequentist probability, we can equate | |
972 | * a task's usage of a particular page (n_p) per total usage of this | |
973 | * page (n_t) (in a given time-span) to a probability. | |
974 | * | |
975 | * Our periodic faults will sample this probability and getting the | |
976 | * same result twice in a row, given these samples are fully | |
977 | * independent, is then given by P(n)^2, provided our sample period | |
978 | * is sufficiently short compared to the usage pattern. | |
979 | * | |
980 | * This quadric squishes small probabilities, making it less likely we | |
981 | * act on an unlikely task<->page relation. | |
982 | */ | |
983 | last_cpupid = page_cpupid_xchg_last(page, this_cpupid); | |
984 | if (!cpupid_pid_unset(last_cpupid) && | |
985 | cpupid_to_nid(last_cpupid) != dst_nid) | |
986 | return false; | |
987 | ||
988 | /* Always allow migrate on private faults */ | |
989 | if (cpupid_match_pid(p, last_cpupid)) | |
990 | return true; | |
991 | ||
992 | /* A shared fault, but p->numa_group has not been set up yet. */ | |
993 | if (!ng) | |
994 | return true; | |
995 | ||
996 | /* | |
997 | * Do not migrate if the destination is not a node that | |
998 | * is actively used by this numa group. | |
999 | */ | |
1000 | if (!node_isset(dst_nid, ng->active_nodes)) | |
1001 | return false; | |
1002 | ||
1003 | /* | |
1004 | * Source is a node that is not actively used by this | |
1005 | * numa group, while the destination is. Migrate. | |
1006 | */ | |
1007 | if (!node_isset(src_nid, ng->active_nodes)) | |
1008 | return true; | |
1009 | ||
1010 | /* | |
1011 | * Both source and destination are nodes in active | |
1012 | * use by this numa group. Maximize memory bandwidth | |
1013 | * by migrating from more heavily used groups, to less | |
1014 | * heavily used ones, spreading the load around. | |
1015 | * Use a 1/4 hysteresis to avoid spurious page movement. | |
1016 | */ | |
1017 | return group_faults(p, dst_nid) < (group_faults(p, src_nid) * 3 / 4); | |
1018 | } | |
1019 | ||
e6628d5b | 1020 | static unsigned long weighted_cpuload(const int cpu); |
58d081b5 MG |
1021 | static unsigned long source_load(int cpu, int type); |
1022 | static unsigned long target_load(int cpu, int type); | |
1023 | static unsigned long power_of(int cpu); | |
1024 | static long effective_load(struct task_group *tg, int cpu, long wl, long wg); | |
1025 | ||
fb13c7ee | 1026 | /* Cached statistics for all CPUs within a node */ |
58d081b5 | 1027 | struct numa_stats { |
fb13c7ee | 1028 | unsigned long nr_running; |
58d081b5 | 1029 | unsigned long load; |
fb13c7ee MG |
1030 | |
1031 | /* Total compute capacity of CPUs on a node */ | |
1032 | unsigned long power; | |
1033 | ||
1034 | /* Approximate capacity in terms of runnable tasks on a node */ | |
1035 | unsigned long capacity; | |
1036 | int has_capacity; | |
58d081b5 | 1037 | }; |
e6628d5b | 1038 | |
fb13c7ee MG |
1039 | /* |
1040 | * XXX borrowed from update_sg_lb_stats | |
1041 | */ | |
1042 | static void update_numa_stats(struct numa_stats *ns, int nid) | |
1043 | { | |
5eca82a9 | 1044 | int cpu, cpus = 0; |
fb13c7ee MG |
1045 | |
1046 | memset(ns, 0, sizeof(*ns)); | |
1047 | for_each_cpu(cpu, cpumask_of_node(nid)) { | |
1048 | struct rq *rq = cpu_rq(cpu); | |
1049 | ||
1050 | ns->nr_running += rq->nr_running; | |
1051 | ns->load += weighted_cpuload(cpu); | |
1052 | ns->power += power_of(cpu); | |
5eca82a9 PZ |
1053 | |
1054 | cpus++; | |
fb13c7ee MG |
1055 | } |
1056 | ||
5eca82a9 PZ |
1057 | /* |
1058 | * If we raced with hotplug and there are no CPUs left in our mask | |
1059 | * the @ns structure is NULL'ed and task_numa_compare() will | |
1060 | * not find this node attractive. | |
1061 | * | |
1062 | * We'll either bail at !has_capacity, or we'll detect a huge imbalance | |
1063 | * and bail there. | |
1064 | */ | |
1065 | if (!cpus) | |
1066 | return; | |
1067 | ||
fb13c7ee MG |
1068 | ns->load = (ns->load * SCHED_POWER_SCALE) / ns->power; |
1069 | ns->capacity = DIV_ROUND_CLOSEST(ns->power, SCHED_POWER_SCALE); | |
1070 | ns->has_capacity = (ns->nr_running < ns->capacity); | |
1071 | } | |
1072 | ||
58d081b5 MG |
1073 | struct task_numa_env { |
1074 | struct task_struct *p; | |
e6628d5b | 1075 | |
58d081b5 MG |
1076 | int src_cpu, src_nid; |
1077 | int dst_cpu, dst_nid; | |
e6628d5b | 1078 | |
58d081b5 | 1079 | struct numa_stats src_stats, dst_stats; |
e6628d5b | 1080 | |
40ea2b42 | 1081 | int imbalance_pct; |
fb13c7ee MG |
1082 | |
1083 | struct task_struct *best_task; | |
1084 | long best_imp; | |
58d081b5 MG |
1085 | int best_cpu; |
1086 | }; | |
1087 | ||
fb13c7ee MG |
1088 | static void task_numa_assign(struct task_numa_env *env, |
1089 | struct task_struct *p, long imp) | |
1090 | { | |
1091 | if (env->best_task) | |
1092 | put_task_struct(env->best_task); | |
1093 | if (p) | |
1094 | get_task_struct(p); | |
1095 | ||
1096 | env->best_task = p; | |
1097 | env->best_imp = imp; | |
1098 | env->best_cpu = env->dst_cpu; | |
1099 | } | |
1100 | ||
1101 | /* | |
1102 | * This checks if the overall compute and NUMA accesses of the system would | |
1103 | * be improved if the source tasks was migrated to the target dst_cpu taking | |
1104 | * into account that it might be best if task running on the dst_cpu should | |
1105 | * be exchanged with the source task | |
1106 | */ | |
887c290e RR |
1107 | static void task_numa_compare(struct task_numa_env *env, |
1108 | long taskimp, long groupimp) | |
fb13c7ee MG |
1109 | { |
1110 | struct rq *src_rq = cpu_rq(env->src_cpu); | |
1111 | struct rq *dst_rq = cpu_rq(env->dst_cpu); | |
1112 | struct task_struct *cur; | |
1113 | long dst_load, src_load; | |
1114 | long load; | |
887c290e | 1115 | long imp = (groupimp > 0) ? groupimp : taskimp; |
fb13c7ee MG |
1116 | |
1117 | rcu_read_lock(); | |
1118 | cur = ACCESS_ONCE(dst_rq->curr); | |
1119 | if (cur->pid == 0) /* idle */ | |
1120 | cur = NULL; | |
1121 | ||
1122 | /* | |
1123 | * "imp" is the fault differential for the source task between the | |
1124 | * source and destination node. Calculate the total differential for | |
1125 | * the source task and potential destination task. The more negative | |
1126 | * the value is, the more rmeote accesses that would be expected to | |
1127 | * be incurred if the tasks were swapped. | |
1128 | */ | |
1129 | if (cur) { | |
1130 | /* Skip this swap candidate if cannot move to the source cpu */ | |
1131 | if (!cpumask_test_cpu(env->src_cpu, tsk_cpus_allowed(cur))) | |
1132 | goto unlock; | |
1133 | ||
887c290e RR |
1134 | /* |
1135 | * If dst and source tasks are in the same NUMA group, or not | |
ca28aa53 | 1136 | * in any group then look only at task weights. |
887c290e | 1137 | */ |
ca28aa53 | 1138 | if (cur->numa_group == env->p->numa_group) { |
887c290e RR |
1139 | imp = taskimp + task_weight(cur, env->src_nid) - |
1140 | task_weight(cur, env->dst_nid); | |
ca28aa53 RR |
1141 | /* |
1142 | * Add some hysteresis to prevent swapping the | |
1143 | * tasks within a group over tiny differences. | |
1144 | */ | |
1145 | if (cur->numa_group) | |
1146 | imp -= imp/16; | |
887c290e | 1147 | } else { |
ca28aa53 RR |
1148 | /* |
1149 | * Compare the group weights. If a task is all by | |
1150 | * itself (not part of a group), use the task weight | |
1151 | * instead. | |
1152 | */ | |
1153 | if (env->p->numa_group) | |
1154 | imp = groupimp; | |
1155 | else | |
1156 | imp = taskimp; | |
1157 | ||
1158 | if (cur->numa_group) | |
1159 | imp += group_weight(cur, env->src_nid) - | |
1160 | group_weight(cur, env->dst_nid); | |
1161 | else | |
1162 | imp += task_weight(cur, env->src_nid) - | |
1163 | task_weight(cur, env->dst_nid); | |
887c290e | 1164 | } |
fb13c7ee MG |
1165 | } |
1166 | ||
1167 | if (imp < env->best_imp) | |
1168 | goto unlock; | |
1169 | ||
1170 | if (!cur) { | |
1171 | /* Is there capacity at our destination? */ | |
1172 | if (env->src_stats.has_capacity && | |
1173 | !env->dst_stats.has_capacity) | |
1174 | goto unlock; | |
1175 | ||
1176 | goto balance; | |
1177 | } | |
1178 | ||
1179 | /* Balance doesn't matter much if we're running a task per cpu */ | |
1180 | if (src_rq->nr_running == 1 && dst_rq->nr_running == 1) | |
1181 | goto assign; | |
1182 | ||
1183 | /* | |
1184 | * In the overloaded case, try and keep the load balanced. | |
1185 | */ | |
1186 | balance: | |
1187 | dst_load = env->dst_stats.load; | |
1188 | src_load = env->src_stats.load; | |
1189 | ||
1190 | /* XXX missing power terms */ | |
1191 | load = task_h_load(env->p); | |
1192 | dst_load += load; | |
1193 | src_load -= load; | |
1194 | ||
1195 | if (cur) { | |
1196 | load = task_h_load(cur); | |
1197 | dst_load -= load; | |
1198 | src_load += load; | |
1199 | } | |
1200 | ||
1201 | /* make src_load the smaller */ | |
1202 | if (dst_load < src_load) | |
1203 | swap(dst_load, src_load); | |
1204 | ||
1205 | if (src_load * env->imbalance_pct < dst_load * 100) | |
1206 | goto unlock; | |
1207 | ||
1208 | assign: | |
1209 | task_numa_assign(env, cur, imp); | |
1210 | unlock: | |
1211 | rcu_read_unlock(); | |
1212 | } | |
1213 | ||
887c290e RR |
1214 | static void task_numa_find_cpu(struct task_numa_env *env, |
1215 | long taskimp, long groupimp) | |
2c8a50aa MG |
1216 | { |
1217 | int cpu; | |
1218 | ||
1219 | for_each_cpu(cpu, cpumask_of_node(env->dst_nid)) { | |
1220 | /* Skip this CPU if the source task cannot migrate */ | |
1221 | if (!cpumask_test_cpu(cpu, tsk_cpus_allowed(env->p))) | |
1222 | continue; | |
1223 | ||
1224 | env->dst_cpu = cpu; | |
887c290e | 1225 | task_numa_compare(env, taskimp, groupimp); |
2c8a50aa MG |
1226 | } |
1227 | } | |
1228 | ||
58d081b5 MG |
1229 | static int task_numa_migrate(struct task_struct *p) |
1230 | { | |
58d081b5 MG |
1231 | struct task_numa_env env = { |
1232 | .p = p, | |
fb13c7ee | 1233 | |
58d081b5 | 1234 | .src_cpu = task_cpu(p), |
b32e86b4 | 1235 | .src_nid = task_node(p), |
fb13c7ee MG |
1236 | |
1237 | .imbalance_pct = 112, | |
1238 | ||
1239 | .best_task = NULL, | |
1240 | .best_imp = 0, | |
1241 | .best_cpu = -1 | |
58d081b5 MG |
1242 | }; |
1243 | struct sched_domain *sd; | |
887c290e | 1244 | unsigned long taskweight, groupweight; |
2c8a50aa | 1245 | int nid, ret; |
887c290e | 1246 | long taskimp, groupimp; |
e6628d5b | 1247 | |
58d081b5 | 1248 | /* |
fb13c7ee MG |
1249 | * Pick the lowest SD_NUMA domain, as that would have the smallest |
1250 | * imbalance and would be the first to start moving tasks about. | |
1251 | * | |
1252 | * And we want to avoid any moving of tasks about, as that would create | |
1253 | * random movement of tasks -- counter the numa conditions we're trying | |
1254 | * to satisfy here. | |
58d081b5 MG |
1255 | */ |
1256 | rcu_read_lock(); | |
fb13c7ee | 1257 | sd = rcu_dereference(per_cpu(sd_numa, env.src_cpu)); |
46a73e8a RR |
1258 | if (sd) |
1259 | env.imbalance_pct = 100 + (sd->imbalance_pct - 100) / 2; | |
e6628d5b MG |
1260 | rcu_read_unlock(); |
1261 | ||
46a73e8a RR |
1262 | /* |
1263 | * Cpusets can break the scheduler domain tree into smaller | |
1264 | * balance domains, some of which do not cross NUMA boundaries. | |
1265 | * Tasks that are "trapped" in such domains cannot be migrated | |
1266 | * elsewhere, so there is no point in (re)trying. | |
1267 | */ | |
1268 | if (unlikely(!sd)) { | |
de1b301a | 1269 | p->numa_preferred_nid = task_node(p); |
46a73e8a RR |
1270 | return -EINVAL; |
1271 | } | |
1272 | ||
887c290e RR |
1273 | taskweight = task_weight(p, env.src_nid); |
1274 | groupweight = group_weight(p, env.src_nid); | |
fb13c7ee | 1275 | update_numa_stats(&env.src_stats, env.src_nid); |
2c8a50aa | 1276 | env.dst_nid = p->numa_preferred_nid; |
887c290e RR |
1277 | taskimp = task_weight(p, env.dst_nid) - taskweight; |
1278 | groupimp = group_weight(p, env.dst_nid) - groupweight; | |
2c8a50aa | 1279 | update_numa_stats(&env.dst_stats, env.dst_nid); |
58d081b5 | 1280 | |
e1dda8a7 RR |
1281 | /* If the preferred nid has capacity, try to use it. */ |
1282 | if (env.dst_stats.has_capacity) | |
887c290e | 1283 | task_numa_find_cpu(&env, taskimp, groupimp); |
e1dda8a7 RR |
1284 | |
1285 | /* No space available on the preferred nid. Look elsewhere. */ | |
1286 | if (env.best_cpu == -1) { | |
2c8a50aa MG |
1287 | for_each_online_node(nid) { |
1288 | if (nid == env.src_nid || nid == p->numa_preferred_nid) | |
1289 | continue; | |
58d081b5 | 1290 | |
83e1d2cd | 1291 | /* Only consider nodes where both task and groups benefit */ |
887c290e RR |
1292 | taskimp = task_weight(p, nid) - taskweight; |
1293 | groupimp = group_weight(p, nid) - groupweight; | |
1294 | if (taskimp < 0 && groupimp < 0) | |
fb13c7ee MG |
1295 | continue; |
1296 | ||
2c8a50aa MG |
1297 | env.dst_nid = nid; |
1298 | update_numa_stats(&env.dst_stats, env.dst_nid); | |
887c290e | 1299 | task_numa_find_cpu(&env, taskimp, groupimp); |
58d081b5 MG |
1300 | } |
1301 | } | |
1302 | ||
fb13c7ee MG |
1303 | /* No better CPU than the current one was found. */ |
1304 | if (env.best_cpu == -1) | |
1305 | return -EAGAIN; | |
1306 | ||
0ec8aa00 PZ |
1307 | sched_setnuma(p, env.dst_nid); |
1308 | ||
04bb2f94 RR |
1309 | /* |
1310 | * Reset the scan period if the task is being rescheduled on an | |
1311 | * alternative node to recheck if the tasks is now properly placed. | |
1312 | */ | |
1313 | p->numa_scan_period = task_scan_min(p); | |
1314 | ||
fb13c7ee MG |
1315 | if (env.best_task == NULL) { |
1316 | int ret = migrate_task_to(p, env.best_cpu); | |
1317 | return ret; | |
1318 | } | |
1319 | ||
1320 | ret = migrate_swap(p, env.best_task); | |
1321 | put_task_struct(env.best_task); | |
1322 | return ret; | |
e6628d5b MG |
1323 | } |
1324 | ||
6b9a7460 MG |
1325 | /* Attempt to migrate a task to a CPU on the preferred node. */ |
1326 | static void numa_migrate_preferred(struct task_struct *p) | |
1327 | { | |
2739d3ee | 1328 | /* This task has no NUMA fault statistics yet */ |
ff1df896 | 1329 | if (unlikely(p->numa_preferred_nid == -1 || !p->numa_faults_memory)) |
6b9a7460 MG |
1330 | return; |
1331 | ||
2739d3ee RR |
1332 | /* Periodically retry migrating the task to the preferred node */ |
1333 | p->numa_migrate_retry = jiffies + HZ; | |
1334 | ||
1335 | /* Success if task is already running on preferred CPU */ | |
de1b301a | 1336 | if (task_node(p) == p->numa_preferred_nid) |
6b9a7460 MG |
1337 | return; |
1338 | ||
1339 | /* Otherwise, try migrate to a CPU on the preferred node */ | |
2739d3ee | 1340 | task_numa_migrate(p); |
6b9a7460 MG |
1341 | } |
1342 | ||
20e07dea RR |
1343 | /* |
1344 | * Find the nodes on which the workload is actively running. We do this by | |
1345 | * tracking the nodes from which NUMA hinting faults are triggered. This can | |
1346 | * be different from the set of nodes where the workload's memory is currently | |
1347 | * located. | |
1348 | * | |
1349 | * The bitmask is used to make smarter decisions on when to do NUMA page | |
1350 | * migrations, To prevent flip-flopping, and excessive page migrations, nodes | |
1351 | * are added when they cause over 6/16 of the maximum number of faults, but | |
1352 | * only removed when they drop below 3/16. | |
1353 | */ | |
1354 | static void update_numa_active_node_mask(struct numa_group *numa_group) | |
1355 | { | |
1356 | unsigned long faults, max_faults = 0; | |
1357 | int nid; | |
1358 | ||
1359 | for_each_online_node(nid) { | |
1360 | faults = group_faults_cpu(numa_group, nid); | |
1361 | if (faults > max_faults) | |
1362 | max_faults = faults; | |
1363 | } | |
1364 | ||
1365 | for_each_online_node(nid) { | |
1366 | faults = group_faults_cpu(numa_group, nid); | |
1367 | if (!node_isset(nid, numa_group->active_nodes)) { | |
1368 | if (faults > max_faults * 6 / 16) | |
1369 | node_set(nid, numa_group->active_nodes); | |
1370 | } else if (faults < max_faults * 3 / 16) | |
1371 | node_clear(nid, numa_group->active_nodes); | |
1372 | } | |
1373 | } | |
1374 | ||
04bb2f94 RR |
1375 | /* |
1376 | * When adapting the scan rate, the period is divided into NUMA_PERIOD_SLOTS | |
1377 | * increments. The more local the fault statistics are, the higher the scan | |
1378 | * period will be for the next scan window. If local/remote ratio is below | |
1379 | * NUMA_PERIOD_THRESHOLD (where range of ratio is 1..NUMA_PERIOD_SLOTS) the | |
1380 | * scan period will decrease | |
1381 | */ | |
1382 | #define NUMA_PERIOD_SLOTS 10 | |
1383 | #define NUMA_PERIOD_THRESHOLD 3 | |
1384 | ||
1385 | /* | |
1386 | * Increase the scan period (slow down scanning) if the majority of | |
1387 | * our memory is already on our local node, or if the majority of | |
1388 | * the page accesses are shared with other processes. | |
1389 | * Otherwise, decrease the scan period. | |
1390 | */ | |
1391 | static void update_task_scan_period(struct task_struct *p, | |
1392 | unsigned long shared, unsigned long private) | |
1393 | { | |
1394 | unsigned int period_slot; | |
1395 | int ratio; | |
1396 | int diff; | |
1397 | ||
1398 | unsigned long remote = p->numa_faults_locality[0]; | |
1399 | unsigned long local = p->numa_faults_locality[1]; | |
1400 | ||
1401 | /* | |
1402 | * If there were no record hinting faults then either the task is | |
1403 | * completely idle or all activity is areas that are not of interest | |
1404 | * to automatic numa balancing. Scan slower | |
1405 | */ | |
1406 | if (local + shared == 0) { | |
1407 | p->numa_scan_period = min(p->numa_scan_period_max, | |
1408 | p->numa_scan_period << 1); | |
1409 | ||
1410 | p->mm->numa_next_scan = jiffies + | |
1411 | msecs_to_jiffies(p->numa_scan_period); | |
1412 | ||
1413 | return; | |
1414 | } | |
1415 | ||
1416 | /* | |
1417 | * Prepare to scale scan period relative to the current period. | |
1418 | * == NUMA_PERIOD_THRESHOLD scan period stays the same | |
1419 | * < NUMA_PERIOD_THRESHOLD scan period decreases (scan faster) | |
1420 | * >= NUMA_PERIOD_THRESHOLD scan period increases (scan slower) | |
1421 | */ | |
1422 | period_slot = DIV_ROUND_UP(p->numa_scan_period, NUMA_PERIOD_SLOTS); | |
1423 | ratio = (local * NUMA_PERIOD_SLOTS) / (local + remote); | |
1424 | if (ratio >= NUMA_PERIOD_THRESHOLD) { | |
1425 | int slot = ratio - NUMA_PERIOD_THRESHOLD; | |
1426 | if (!slot) | |
1427 | slot = 1; | |
1428 | diff = slot * period_slot; | |
1429 | } else { | |
1430 | diff = -(NUMA_PERIOD_THRESHOLD - ratio) * period_slot; | |
1431 | ||
1432 | /* | |
1433 | * Scale scan rate increases based on sharing. There is an | |
1434 | * inverse relationship between the degree of sharing and | |
1435 | * the adjustment made to the scanning period. Broadly | |
1436 | * speaking the intent is that there is little point | |
1437 | * scanning faster if shared accesses dominate as it may | |
1438 | * simply bounce migrations uselessly | |
1439 | */ | |
04bb2f94 RR |
1440 | ratio = DIV_ROUND_UP(private * NUMA_PERIOD_SLOTS, (private + shared)); |
1441 | diff = (diff * ratio) / NUMA_PERIOD_SLOTS; | |
1442 | } | |
1443 | ||
1444 | p->numa_scan_period = clamp(p->numa_scan_period + diff, | |
1445 | task_scan_min(p), task_scan_max(p)); | |
1446 | memset(p->numa_faults_locality, 0, sizeof(p->numa_faults_locality)); | |
1447 | } | |
1448 | ||
cbee9f88 PZ |
1449 | static void task_numa_placement(struct task_struct *p) |
1450 | { | |
83e1d2cd MG |
1451 | int seq, nid, max_nid = -1, max_group_nid = -1; |
1452 | unsigned long max_faults = 0, max_group_faults = 0; | |
04bb2f94 | 1453 | unsigned long fault_types[2] = { 0, 0 }; |
7dbd13ed | 1454 | spinlock_t *group_lock = NULL; |
cbee9f88 | 1455 | |
2832bc19 | 1456 | seq = ACCESS_ONCE(p->mm->numa_scan_seq); |
cbee9f88 PZ |
1457 | if (p->numa_scan_seq == seq) |
1458 | return; | |
1459 | p->numa_scan_seq = seq; | |
598f0ec0 | 1460 | p->numa_scan_period_max = task_scan_max(p); |
cbee9f88 | 1461 | |
7dbd13ed MG |
1462 | /* If the task is part of a group prevent parallel updates to group stats */ |
1463 | if (p->numa_group) { | |
1464 | group_lock = &p->numa_group->lock; | |
1465 | spin_lock(group_lock); | |
1466 | } | |
1467 | ||
688b7585 MG |
1468 | /* Find the node with the highest number of faults */ |
1469 | for_each_online_node(nid) { | |
83e1d2cd | 1470 | unsigned long faults = 0, group_faults = 0; |
ac8e895b | 1471 | int priv, i; |
745d6147 | 1472 | |
ac8e895b | 1473 | for (priv = 0; priv < 2; priv++) { |
50ec8a40 | 1474 | long diff, f_diff; |
8c8a743c | 1475 | |
ac8e895b | 1476 | i = task_faults_idx(nid, priv); |
ff1df896 | 1477 | diff = -p->numa_faults_memory[i]; |
50ec8a40 | 1478 | f_diff = -p->numa_faults_cpu[i]; |
745d6147 | 1479 | |
ac8e895b | 1480 | /* Decay existing window, copy faults since last scan */ |
ff1df896 RR |
1481 | p->numa_faults_memory[i] >>= 1; |
1482 | p->numa_faults_memory[i] += p->numa_faults_buffer_memory[i]; | |
1483 | fault_types[priv] += p->numa_faults_buffer_memory[i]; | |
1484 | p->numa_faults_buffer_memory[i] = 0; | |
fb13c7ee | 1485 | |
50ec8a40 RR |
1486 | p->numa_faults_cpu[i] >>= 1; |
1487 | p->numa_faults_cpu[i] += p->numa_faults_buffer_cpu[i]; | |
1488 | p->numa_faults_buffer_cpu[i] = 0; | |
1489 | ||
ff1df896 RR |
1490 | faults += p->numa_faults_memory[i]; |
1491 | diff += p->numa_faults_memory[i]; | |
50ec8a40 | 1492 | f_diff += p->numa_faults_cpu[i]; |
83e1d2cd | 1493 | p->total_numa_faults += diff; |
8c8a743c PZ |
1494 | if (p->numa_group) { |
1495 | /* safe because we can only change our own group */ | |
989348b5 | 1496 | p->numa_group->faults[i] += diff; |
50ec8a40 | 1497 | p->numa_group->faults_cpu[i] += f_diff; |
989348b5 MG |
1498 | p->numa_group->total_faults += diff; |
1499 | group_faults += p->numa_group->faults[i]; | |
8c8a743c | 1500 | } |
ac8e895b MG |
1501 | } |
1502 | ||
688b7585 MG |
1503 | if (faults > max_faults) { |
1504 | max_faults = faults; | |
1505 | max_nid = nid; | |
1506 | } | |
83e1d2cd MG |
1507 | |
1508 | if (group_faults > max_group_faults) { | |
1509 | max_group_faults = group_faults; | |
1510 | max_group_nid = nid; | |
1511 | } | |
1512 | } | |
1513 | ||
04bb2f94 RR |
1514 | update_task_scan_period(p, fault_types[0], fault_types[1]); |
1515 | ||
7dbd13ed | 1516 | if (p->numa_group) { |
20e07dea | 1517 | update_numa_active_node_mask(p->numa_group); |
7dbd13ed MG |
1518 | /* |
1519 | * If the preferred task and group nids are different, | |
1520 | * iterate over the nodes again to find the best place. | |
1521 | */ | |
1522 | if (max_nid != max_group_nid) { | |
1523 | unsigned long weight, max_weight = 0; | |
1524 | ||
1525 | for_each_online_node(nid) { | |
1526 | weight = task_weight(p, nid) + group_weight(p, nid); | |
1527 | if (weight > max_weight) { | |
1528 | max_weight = weight; | |
1529 | max_nid = nid; | |
1530 | } | |
83e1d2cd MG |
1531 | } |
1532 | } | |
7dbd13ed MG |
1533 | |
1534 | spin_unlock(group_lock); | |
688b7585 MG |
1535 | } |
1536 | ||
6b9a7460 | 1537 | /* Preferred node as the node with the most faults */ |
3a7053b3 | 1538 | if (max_faults && max_nid != p->numa_preferred_nid) { |
e6628d5b | 1539 | /* Update the preferred nid and migrate task if possible */ |
0ec8aa00 | 1540 | sched_setnuma(p, max_nid); |
6b9a7460 | 1541 | numa_migrate_preferred(p); |
3a7053b3 | 1542 | } |
cbee9f88 PZ |
1543 | } |
1544 | ||
8c8a743c PZ |
1545 | static inline int get_numa_group(struct numa_group *grp) |
1546 | { | |
1547 | return atomic_inc_not_zero(&grp->refcount); | |
1548 | } | |
1549 | ||
1550 | static inline void put_numa_group(struct numa_group *grp) | |
1551 | { | |
1552 | if (atomic_dec_and_test(&grp->refcount)) | |
1553 | kfree_rcu(grp, rcu); | |
1554 | } | |
1555 | ||
3e6a9418 MG |
1556 | static void task_numa_group(struct task_struct *p, int cpupid, int flags, |
1557 | int *priv) | |
8c8a743c PZ |
1558 | { |
1559 | struct numa_group *grp, *my_grp; | |
1560 | struct task_struct *tsk; | |
1561 | bool join = false; | |
1562 | int cpu = cpupid_to_cpu(cpupid); | |
1563 | int i; | |
1564 | ||
1565 | if (unlikely(!p->numa_group)) { | |
1566 | unsigned int size = sizeof(struct numa_group) + | |
50ec8a40 | 1567 | 4*nr_node_ids*sizeof(unsigned long); |
8c8a743c PZ |
1568 | |
1569 | grp = kzalloc(size, GFP_KERNEL | __GFP_NOWARN); | |
1570 | if (!grp) | |
1571 | return; | |
1572 | ||
1573 | atomic_set(&grp->refcount, 1); | |
1574 | spin_lock_init(&grp->lock); | |
1575 | INIT_LIST_HEAD(&grp->task_list); | |
e29cf08b | 1576 | grp->gid = p->pid; |
50ec8a40 RR |
1577 | /* Second half of the array tracks nids where faults happen */ |
1578 | grp->faults_cpu = grp->faults + 2 * nr_node_ids; | |
8c8a743c | 1579 | |
20e07dea RR |
1580 | node_set(task_node(current), grp->active_nodes); |
1581 | ||
50ec8a40 | 1582 | for (i = 0; i < 4*nr_node_ids; i++) |
ff1df896 | 1583 | grp->faults[i] = p->numa_faults_memory[i]; |
8c8a743c | 1584 | |
989348b5 | 1585 | grp->total_faults = p->total_numa_faults; |
83e1d2cd | 1586 | |
8c8a743c PZ |
1587 | list_add(&p->numa_entry, &grp->task_list); |
1588 | grp->nr_tasks++; | |
1589 | rcu_assign_pointer(p->numa_group, grp); | |
1590 | } | |
1591 | ||
1592 | rcu_read_lock(); | |
1593 | tsk = ACCESS_ONCE(cpu_rq(cpu)->curr); | |
1594 | ||
1595 | if (!cpupid_match_pid(tsk, cpupid)) | |
3354781a | 1596 | goto no_join; |
8c8a743c PZ |
1597 | |
1598 | grp = rcu_dereference(tsk->numa_group); | |
1599 | if (!grp) | |
3354781a | 1600 | goto no_join; |
8c8a743c PZ |
1601 | |
1602 | my_grp = p->numa_group; | |
1603 | if (grp == my_grp) | |
3354781a | 1604 | goto no_join; |
8c8a743c PZ |
1605 | |
1606 | /* | |
1607 | * Only join the other group if its bigger; if we're the bigger group, | |
1608 | * the other task will join us. | |
1609 | */ | |
1610 | if (my_grp->nr_tasks > grp->nr_tasks) | |
3354781a | 1611 | goto no_join; |
8c8a743c PZ |
1612 | |
1613 | /* | |
1614 | * Tie-break on the grp address. | |
1615 | */ | |
1616 | if (my_grp->nr_tasks == grp->nr_tasks && my_grp > grp) | |
3354781a | 1617 | goto no_join; |
8c8a743c | 1618 | |
dabe1d99 RR |
1619 | /* Always join threads in the same process. */ |
1620 | if (tsk->mm == current->mm) | |
1621 | join = true; | |
1622 | ||
1623 | /* Simple filter to avoid false positives due to PID collisions */ | |
1624 | if (flags & TNF_SHARED) | |
1625 | join = true; | |
8c8a743c | 1626 | |
3e6a9418 MG |
1627 | /* Update priv based on whether false sharing was detected */ |
1628 | *priv = !join; | |
1629 | ||
dabe1d99 | 1630 | if (join && !get_numa_group(grp)) |
3354781a | 1631 | goto no_join; |
8c8a743c | 1632 | |
8c8a743c PZ |
1633 | rcu_read_unlock(); |
1634 | ||
1635 | if (!join) | |
1636 | return; | |
1637 | ||
989348b5 MG |
1638 | double_lock(&my_grp->lock, &grp->lock); |
1639 | ||
50ec8a40 | 1640 | for (i = 0; i < 4*nr_node_ids; i++) { |
ff1df896 RR |
1641 | my_grp->faults[i] -= p->numa_faults_memory[i]; |
1642 | grp->faults[i] += p->numa_faults_memory[i]; | |
8c8a743c | 1643 | } |
989348b5 MG |
1644 | my_grp->total_faults -= p->total_numa_faults; |
1645 | grp->total_faults += p->total_numa_faults; | |
8c8a743c PZ |
1646 | |
1647 | list_move(&p->numa_entry, &grp->task_list); | |
1648 | my_grp->nr_tasks--; | |
1649 | grp->nr_tasks++; | |
1650 | ||
1651 | spin_unlock(&my_grp->lock); | |
1652 | spin_unlock(&grp->lock); | |
1653 | ||
1654 | rcu_assign_pointer(p->numa_group, grp); | |
1655 | ||
1656 | put_numa_group(my_grp); | |
3354781a PZ |
1657 | return; |
1658 | ||
1659 | no_join: | |
1660 | rcu_read_unlock(); | |
1661 | return; | |
8c8a743c PZ |
1662 | } |
1663 | ||
1664 | void task_numa_free(struct task_struct *p) | |
1665 | { | |
1666 | struct numa_group *grp = p->numa_group; | |
1667 | int i; | |
ff1df896 | 1668 | void *numa_faults = p->numa_faults_memory; |
8c8a743c PZ |
1669 | |
1670 | if (grp) { | |
989348b5 | 1671 | spin_lock(&grp->lock); |
50ec8a40 | 1672 | for (i = 0; i < 4*nr_node_ids; i++) |
ff1df896 | 1673 | grp->faults[i] -= p->numa_faults_memory[i]; |
989348b5 | 1674 | grp->total_faults -= p->total_numa_faults; |
83e1d2cd | 1675 | |
8c8a743c PZ |
1676 | list_del(&p->numa_entry); |
1677 | grp->nr_tasks--; | |
1678 | spin_unlock(&grp->lock); | |
1679 | rcu_assign_pointer(p->numa_group, NULL); | |
1680 | put_numa_group(grp); | |
1681 | } | |
1682 | ||
ff1df896 RR |
1683 | p->numa_faults_memory = NULL; |
1684 | p->numa_faults_buffer_memory = NULL; | |
50ec8a40 RR |
1685 | p->numa_faults_cpu= NULL; |
1686 | p->numa_faults_buffer_cpu = NULL; | |
82727018 | 1687 | kfree(numa_faults); |
8c8a743c PZ |
1688 | } |
1689 | ||
cbee9f88 PZ |
1690 | /* |
1691 | * Got a PROT_NONE fault for a page on @node. | |
1692 | */ | |
6688cc05 | 1693 | void task_numa_fault(int last_cpupid, int node, int pages, int flags) |
cbee9f88 PZ |
1694 | { |
1695 | struct task_struct *p = current; | |
6688cc05 | 1696 | bool migrated = flags & TNF_MIGRATED; |
50ec8a40 | 1697 | int this_node = task_node(current); |
ac8e895b | 1698 | int priv; |
cbee9f88 | 1699 | |
10e84b97 | 1700 | if (!numabalancing_enabled) |
1a687c2e MG |
1701 | return; |
1702 | ||
9ff1d9ff MG |
1703 | /* for example, ksmd faulting in a user's mm */ |
1704 | if (!p->mm) | |
1705 | return; | |
1706 | ||
82727018 RR |
1707 | /* Do not worry about placement if exiting */ |
1708 | if (p->state == TASK_DEAD) | |
1709 | return; | |
1710 | ||
f809ca9a | 1711 | /* Allocate buffer to track faults on a per-node basis */ |
ff1df896 | 1712 | if (unlikely(!p->numa_faults_memory)) { |
50ec8a40 | 1713 | int size = sizeof(*p->numa_faults_memory) * 4 * nr_node_ids; |
f809ca9a | 1714 | |
745d6147 | 1715 | /* numa_faults and numa_faults_buffer share the allocation */ |
ff1df896 RR |
1716 | p->numa_faults_memory = kzalloc(size * 2, GFP_KERNEL|__GFP_NOWARN); |
1717 | if (!p->numa_faults_memory) | |
f809ca9a | 1718 | return; |
745d6147 | 1719 | |
ff1df896 | 1720 | BUG_ON(p->numa_faults_buffer_memory); |
50ec8a40 RR |
1721 | p->numa_faults_cpu = p->numa_faults_memory + (2 * nr_node_ids); |
1722 | p->numa_faults_buffer_memory = p->numa_faults_memory + (4 * nr_node_ids); | |
1723 | p->numa_faults_buffer_cpu = p->numa_faults_memory + (6 * nr_node_ids); | |
83e1d2cd | 1724 | p->total_numa_faults = 0; |
04bb2f94 | 1725 | memset(p->numa_faults_locality, 0, sizeof(p->numa_faults_locality)); |
f809ca9a | 1726 | } |
cbee9f88 | 1727 | |
8c8a743c PZ |
1728 | /* |
1729 | * First accesses are treated as private, otherwise consider accesses | |
1730 | * to be private if the accessing pid has not changed | |
1731 | */ | |
1732 | if (unlikely(last_cpupid == (-1 & LAST_CPUPID_MASK))) { | |
1733 | priv = 1; | |
1734 | } else { | |
1735 | priv = cpupid_match_pid(p, last_cpupid); | |
6688cc05 | 1736 | if (!priv && !(flags & TNF_NO_GROUP)) |
3e6a9418 | 1737 | task_numa_group(p, last_cpupid, flags, &priv); |
8c8a743c PZ |
1738 | } |
1739 | ||
cbee9f88 | 1740 | task_numa_placement(p); |
f809ca9a | 1741 | |
2739d3ee RR |
1742 | /* |
1743 | * Retry task to preferred node migration periodically, in case it | |
1744 | * case it previously failed, or the scheduler moved us. | |
1745 | */ | |
1746 | if (time_after(jiffies, p->numa_migrate_retry)) | |
6b9a7460 MG |
1747 | numa_migrate_preferred(p); |
1748 | ||
b32e86b4 IM |
1749 | if (migrated) |
1750 | p->numa_pages_migrated += pages; | |
1751 | ||
ff1df896 | 1752 | p->numa_faults_buffer_memory[task_faults_idx(node, priv)] += pages; |
50ec8a40 | 1753 | p->numa_faults_buffer_cpu[task_faults_idx(this_node, priv)] += pages; |
04bb2f94 | 1754 | p->numa_faults_locality[!!(flags & TNF_FAULT_LOCAL)] += pages; |
cbee9f88 PZ |
1755 | } |
1756 | ||
6e5fb223 PZ |
1757 | static void reset_ptenuma_scan(struct task_struct *p) |
1758 | { | |
1759 | ACCESS_ONCE(p->mm->numa_scan_seq)++; | |
1760 | p->mm->numa_scan_offset = 0; | |
1761 | } | |
1762 | ||
cbee9f88 PZ |
1763 | /* |
1764 | * The expensive part of numa migration is done from task_work context. | |
1765 | * Triggered from task_tick_numa(). | |
1766 | */ | |
1767 | void task_numa_work(struct callback_head *work) | |
1768 | { | |
1769 | unsigned long migrate, next_scan, now = jiffies; | |
1770 | struct task_struct *p = current; | |
1771 | struct mm_struct *mm = p->mm; | |
6e5fb223 | 1772 | struct vm_area_struct *vma; |
9f40604c | 1773 | unsigned long start, end; |
598f0ec0 | 1774 | unsigned long nr_pte_updates = 0; |
9f40604c | 1775 | long pages; |
cbee9f88 PZ |
1776 | |
1777 | WARN_ON_ONCE(p != container_of(work, struct task_struct, numa_work)); | |
1778 | ||
1779 | work->next = work; /* protect against double add */ | |
1780 | /* | |
1781 | * Who cares about NUMA placement when they're dying. | |
1782 | * | |
1783 | * NOTE: make sure not to dereference p->mm before this check, | |
1784 | * exit_task_work() happens _after_ exit_mm() so we could be called | |
1785 | * without p->mm even though we still had it when we enqueued this | |
1786 | * work. | |
1787 | */ | |
1788 | if (p->flags & PF_EXITING) | |
1789 | return; | |
1790 | ||
930aa174 | 1791 | if (!mm->numa_next_scan) { |
7e8d16b6 MG |
1792 | mm->numa_next_scan = now + |
1793 | msecs_to_jiffies(sysctl_numa_balancing_scan_delay); | |
b8593bfd MG |
1794 | } |
1795 | ||
cbee9f88 PZ |
1796 | /* |
1797 | * Enforce maximal scan/migration frequency.. | |
1798 | */ | |
1799 | migrate = mm->numa_next_scan; | |
1800 | if (time_before(now, migrate)) | |
1801 | return; | |
1802 | ||
598f0ec0 MG |
1803 | if (p->numa_scan_period == 0) { |
1804 | p->numa_scan_period_max = task_scan_max(p); | |
1805 | p->numa_scan_period = task_scan_min(p); | |
1806 | } | |
cbee9f88 | 1807 | |
fb003b80 | 1808 | next_scan = now + msecs_to_jiffies(p->numa_scan_period); |
cbee9f88 PZ |
1809 | if (cmpxchg(&mm->numa_next_scan, migrate, next_scan) != migrate) |
1810 | return; | |
1811 | ||
19a78d11 PZ |
1812 | /* |
1813 | * Delay this task enough that another task of this mm will likely win | |
1814 | * the next time around. | |
1815 | */ | |
1816 | p->node_stamp += 2 * TICK_NSEC; | |
1817 | ||
9f40604c MG |
1818 | start = mm->numa_scan_offset; |
1819 | pages = sysctl_numa_balancing_scan_size; | |
1820 | pages <<= 20 - PAGE_SHIFT; /* MB in pages */ | |
1821 | if (!pages) | |
1822 | return; | |
cbee9f88 | 1823 | |
6e5fb223 | 1824 | down_read(&mm->mmap_sem); |
9f40604c | 1825 | vma = find_vma(mm, start); |
6e5fb223 PZ |
1826 | if (!vma) { |
1827 | reset_ptenuma_scan(p); | |
9f40604c | 1828 | start = 0; |
6e5fb223 PZ |
1829 | vma = mm->mmap; |
1830 | } | |
9f40604c | 1831 | for (; vma; vma = vma->vm_next) { |
fc314724 | 1832 | if (!vma_migratable(vma) || !vma_policy_mof(p, vma)) |
6e5fb223 PZ |
1833 | continue; |
1834 | ||
4591ce4f MG |
1835 | /* |
1836 | * Shared library pages mapped by multiple processes are not | |
1837 | * migrated as it is expected they are cache replicated. Avoid | |
1838 | * hinting faults in read-only file-backed mappings or the vdso | |
1839 | * as migrating the pages will be of marginal benefit. | |
1840 | */ | |
1841 | if (!vma->vm_mm || | |
1842 | (vma->vm_file && (vma->vm_flags & (VM_READ|VM_WRITE)) == (VM_READ))) | |
1843 | continue; | |
1844 | ||
3c67f474 MG |
1845 | /* |
1846 | * Skip inaccessible VMAs to avoid any confusion between | |
1847 | * PROT_NONE and NUMA hinting ptes | |
1848 | */ | |
1849 | if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))) | |
1850 | continue; | |
4591ce4f | 1851 | |
9f40604c MG |
1852 | do { |
1853 | start = max(start, vma->vm_start); | |
1854 | end = ALIGN(start + (pages << PAGE_SHIFT), HPAGE_SIZE); | |
1855 | end = min(end, vma->vm_end); | |
598f0ec0 MG |
1856 | nr_pte_updates += change_prot_numa(vma, start, end); |
1857 | ||
1858 | /* | |
1859 | * Scan sysctl_numa_balancing_scan_size but ensure that | |
1860 | * at least one PTE is updated so that unused virtual | |
1861 | * address space is quickly skipped. | |
1862 | */ | |
1863 | if (nr_pte_updates) | |
1864 | pages -= (end - start) >> PAGE_SHIFT; | |
6e5fb223 | 1865 | |
9f40604c MG |
1866 | start = end; |
1867 | if (pages <= 0) | |
1868 | goto out; | |
1869 | } while (end != vma->vm_end); | |
cbee9f88 | 1870 | } |
6e5fb223 | 1871 | |
9f40604c | 1872 | out: |
6e5fb223 | 1873 | /* |
c69307d5 PZ |
1874 | * It is possible to reach the end of the VMA list but the last few |
1875 | * VMAs are not guaranteed to the vma_migratable. If they are not, we | |
1876 | * would find the !migratable VMA on the next scan but not reset the | |
1877 | * scanner to the start so check it now. | |
6e5fb223 PZ |
1878 | */ |
1879 | if (vma) | |
9f40604c | 1880 | mm->numa_scan_offset = start; |
6e5fb223 PZ |
1881 | else |
1882 | reset_ptenuma_scan(p); | |
1883 | up_read(&mm->mmap_sem); | |
cbee9f88 PZ |
1884 | } |
1885 | ||
1886 | /* | |
1887 | * Drive the periodic memory faults.. | |
1888 | */ | |
1889 | void task_tick_numa(struct rq *rq, struct task_struct *curr) | |
1890 | { | |
1891 | struct callback_head *work = &curr->numa_work; | |
1892 | u64 period, now; | |
1893 | ||
1894 | /* | |
1895 | * We don't care about NUMA placement if we don't have memory. | |
1896 | */ | |
1897 | if (!curr->mm || (curr->flags & PF_EXITING) || work->next != work) | |
1898 | return; | |
1899 | ||
1900 | /* | |
1901 | * Using runtime rather than walltime has the dual advantage that | |
1902 | * we (mostly) drive the selection from busy threads and that the | |
1903 | * task needs to have done some actual work before we bother with | |
1904 | * NUMA placement. | |
1905 | */ | |
1906 | now = curr->se.sum_exec_runtime; | |
1907 | period = (u64)curr->numa_scan_period * NSEC_PER_MSEC; | |
1908 | ||
1909 | if (now - curr->node_stamp > period) { | |
4b96a29b | 1910 | if (!curr->node_stamp) |
598f0ec0 | 1911 | curr->numa_scan_period = task_scan_min(curr); |
19a78d11 | 1912 | curr->node_stamp += period; |
cbee9f88 PZ |
1913 | |
1914 | if (!time_before(jiffies, curr->mm->numa_next_scan)) { | |
1915 | init_task_work(work, task_numa_work); /* TODO: move this into sched_fork() */ | |
1916 | task_work_add(curr, work, true); | |
1917 | } | |
1918 | } | |
1919 | } | |
1920 | #else | |
1921 | static void task_tick_numa(struct rq *rq, struct task_struct *curr) | |
1922 | { | |
1923 | } | |
0ec8aa00 PZ |
1924 | |
1925 | static inline void account_numa_enqueue(struct rq *rq, struct task_struct *p) | |
1926 | { | |
1927 | } | |
1928 | ||
1929 | static inline void account_numa_dequeue(struct rq *rq, struct task_struct *p) | |
1930 | { | |
1931 | } | |
cbee9f88 PZ |
1932 | #endif /* CONFIG_NUMA_BALANCING */ |
1933 | ||
30cfdcfc DA |
1934 | static void |
1935 | account_entity_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se) | |
1936 | { | |
1937 | update_load_add(&cfs_rq->load, se->load.weight); | |
c09595f6 | 1938 | if (!parent_entity(se)) |
029632fb | 1939 | update_load_add(&rq_of(cfs_rq)->load, se->load.weight); |
367456c7 | 1940 | #ifdef CONFIG_SMP |
0ec8aa00 PZ |
1941 | if (entity_is_task(se)) { |
1942 | struct rq *rq = rq_of(cfs_rq); | |
1943 | ||
1944 | account_numa_enqueue(rq, task_of(se)); | |
1945 | list_add(&se->group_node, &rq->cfs_tasks); | |
1946 | } | |
367456c7 | 1947 | #endif |
30cfdcfc | 1948 | cfs_rq->nr_running++; |
30cfdcfc DA |
1949 | } |
1950 | ||
1951 | static void | |
1952 | account_entity_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se) | |
1953 | { | |
1954 | update_load_sub(&cfs_rq->load, se->load.weight); | |
c09595f6 | 1955 | if (!parent_entity(se)) |
029632fb | 1956 | update_load_sub(&rq_of(cfs_rq)->load, se->load.weight); |
0ec8aa00 PZ |
1957 | if (entity_is_task(se)) { |
1958 | account_numa_dequeue(rq_of(cfs_rq), task_of(se)); | |
b87f1724 | 1959 | list_del_init(&se->group_node); |
0ec8aa00 | 1960 | } |
30cfdcfc | 1961 | cfs_rq->nr_running--; |
30cfdcfc DA |
1962 | } |
1963 | ||
3ff6dcac YZ |
1964 | #ifdef CONFIG_FAIR_GROUP_SCHED |
1965 | # ifdef CONFIG_SMP | |
cf5f0acf PZ |
1966 | static inline long calc_tg_weight(struct task_group *tg, struct cfs_rq *cfs_rq) |
1967 | { | |
1968 | long tg_weight; | |
1969 | ||
1970 | /* | |
1971 | * Use this CPU's actual weight instead of the last load_contribution | |
1972 | * to gain a more accurate current total weight. See | |
1973 | * update_cfs_rq_load_contribution(). | |
1974 | */ | |
bf5b986e | 1975 | tg_weight = atomic_long_read(&tg->load_avg); |
82958366 | 1976 | tg_weight -= cfs_rq->tg_load_contrib; |
cf5f0acf PZ |
1977 | tg_weight += cfs_rq->load.weight; |
1978 | ||
1979 | return tg_weight; | |
1980 | } | |
1981 | ||
6d5ab293 | 1982 | static long calc_cfs_shares(struct cfs_rq *cfs_rq, struct task_group *tg) |
3ff6dcac | 1983 | { |
cf5f0acf | 1984 | long tg_weight, load, shares; |
3ff6dcac | 1985 | |
cf5f0acf | 1986 | tg_weight = calc_tg_weight(tg, cfs_rq); |
6d5ab293 | 1987 | load = cfs_rq->load.weight; |
3ff6dcac | 1988 | |
3ff6dcac | 1989 | shares = (tg->shares * load); |
cf5f0acf PZ |
1990 | if (tg_weight) |
1991 | shares /= tg_weight; | |
3ff6dcac YZ |
1992 | |
1993 | if (shares < MIN_SHARES) | |
1994 | shares = MIN_SHARES; | |
1995 | if (shares > tg->shares) | |
1996 | shares = tg->shares; | |
1997 | ||
1998 | return shares; | |
1999 | } | |
3ff6dcac | 2000 | # else /* CONFIG_SMP */ |
6d5ab293 | 2001 | static inline long calc_cfs_shares(struct cfs_rq *cfs_rq, struct task_group *tg) |
3ff6dcac YZ |
2002 | { |
2003 | return tg->shares; | |
2004 | } | |
3ff6dcac | 2005 | # endif /* CONFIG_SMP */ |
2069dd75 PZ |
2006 | static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, |
2007 | unsigned long weight) | |
2008 | { | |
19e5eebb PT |
2009 | if (se->on_rq) { |
2010 | /* commit outstanding execution time */ | |
2011 | if (cfs_rq->curr == se) | |
2012 | update_curr(cfs_rq); | |
2069dd75 | 2013 | account_entity_dequeue(cfs_rq, se); |
19e5eebb | 2014 | } |
2069dd75 PZ |
2015 | |
2016 | update_load_set(&se->load, weight); | |
2017 | ||
2018 | if (se->on_rq) | |
2019 | account_entity_enqueue(cfs_rq, se); | |
2020 | } | |
2021 | ||
82958366 PT |
2022 | static inline int throttled_hierarchy(struct cfs_rq *cfs_rq); |
2023 | ||
6d5ab293 | 2024 | static void update_cfs_shares(struct cfs_rq *cfs_rq) |
2069dd75 PZ |
2025 | { |
2026 | struct task_group *tg; | |
2027 | struct sched_entity *se; | |
3ff6dcac | 2028 | long shares; |
2069dd75 | 2029 | |
2069dd75 PZ |
2030 | tg = cfs_rq->tg; |
2031 | se = tg->se[cpu_of(rq_of(cfs_rq))]; | |
64660c86 | 2032 | if (!se || throttled_hierarchy(cfs_rq)) |
2069dd75 | 2033 | return; |
3ff6dcac YZ |
2034 | #ifndef CONFIG_SMP |
2035 | if (likely(se->load.weight == tg->shares)) | |
2036 | return; | |
2037 | #endif | |
6d5ab293 | 2038 | shares = calc_cfs_shares(cfs_rq, tg); |
2069dd75 PZ |
2039 | |
2040 | reweight_entity(cfs_rq_of(se), se, shares); | |
2041 | } | |
2042 | #else /* CONFIG_FAIR_GROUP_SCHED */ | |
6d5ab293 | 2043 | static inline void update_cfs_shares(struct cfs_rq *cfs_rq) |
2069dd75 PZ |
2044 | { |
2045 | } | |
2046 | #endif /* CONFIG_FAIR_GROUP_SCHED */ | |
2047 | ||
141965c7 | 2048 | #ifdef CONFIG_SMP |
5b51f2f8 PT |
2049 | /* |
2050 | * We choose a half-life close to 1 scheduling period. | |
2051 | * Note: The tables below are dependent on this value. | |
2052 | */ | |
2053 | #define LOAD_AVG_PERIOD 32 | |
2054 | #define LOAD_AVG_MAX 47742 /* maximum possible load avg */ | |
2055 | #define LOAD_AVG_MAX_N 345 /* number of full periods to produce LOAD_MAX_AVG */ | |
2056 | ||
2057 | /* Precomputed fixed inverse multiplies for multiplication by y^n */ | |
2058 | static const u32 runnable_avg_yN_inv[] = { | |
2059 | 0xffffffff, 0xfa83b2da, 0xf5257d14, 0xefe4b99a, 0xeac0c6e6, 0xe5b906e6, | |
2060 | 0xe0ccdeeb, 0xdbfbb796, 0xd744fcc9, 0xd2a81d91, 0xce248c14, 0xc9b9bd85, | |
2061 | 0xc5672a10, 0xc12c4cc9, 0xbd08a39e, 0xb8fbaf46, 0xb504f333, 0xb123f581, | |
2062 | 0xad583ee9, 0xa9a15ab4, 0xa5fed6a9, 0xa2704302, 0x9ef5325f, 0x9b8d39b9, | |
2063 | 0x9837f050, 0x94f4efa8, 0x91c3d373, 0x8ea4398a, 0x8b95c1e3, 0x88980e80, | |
2064 | 0x85aac367, 0x82cd8698, | |
2065 | }; | |
2066 | ||
2067 | /* | |
2068 | * Precomputed \Sum y^k { 1<=k<=n }. These are floor(true_value) to prevent | |
2069 | * over-estimates when re-combining. | |
2070 | */ | |
2071 | static const u32 runnable_avg_yN_sum[] = { | |
2072 | 0, 1002, 1982, 2941, 3880, 4798, 5697, 6576, 7437, 8279, 9103, | |
2073 | 9909,10698,11470,12226,12966,13690,14398,15091,15769,16433,17082, | |
2074 | 17718,18340,18949,19545,20128,20698,21256,21802,22336,22859,23371, | |
2075 | }; | |
2076 | ||
9d85f21c PT |
2077 | /* |
2078 | * Approximate: | |
2079 | * val * y^n, where y^32 ~= 0.5 (~1 scheduling period) | |
2080 | */ | |
2081 | static __always_inline u64 decay_load(u64 val, u64 n) | |
2082 | { | |
5b51f2f8 PT |
2083 | unsigned int local_n; |
2084 | ||
2085 | if (!n) | |
2086 | return val; | |
2087 | else if (unlikely(n > LOAD_AVG_PERIOD * 63)) | |
2088 | return 0; | |
2089 | ||
2090 | /* after bounds checking we can collapse to 32-bit */ | |
2091 | local_n = n; | |
2092 | ||
2093 | /* | |
2094 | * As y^PERIOD = 1/2, we can combine | |
2095 | * y^n = 1/2^(n/PERIOD) * k^(n%PERIOD) | |
2096 | * With a look-up table which covers k^n (n<PERIOD) | |
2097 | * | |
2098 | * To achieve constant time decay_load. | |
2099 | */ | |
2100 | if (unlikely(local_n >= LOAD_AVG_PERIOD)) { | |
2101 | val >>= local_n / LOAD_AVG_PERIOD; | |
2102 | local_n %= LOAD_AVG_PERIOD; | |
9d85f21c PT |
2103 | } |
2104 | ||
5b51f2f8 PT |
2105 | val *= runnable_avg_yN_inv[local_n]; |
2106 | /* We don't use SRR here since we always want to round down. */ | |
2107 | return val >> 32; | |
2108 | } | |
2109 | ||
2110 | /* | |
2111 | * For updates fully spanning n periods, the contribution to runnable | |
2112 | * average will be: \Sum 1024*y^n | |
2113 | * | |
2114 | * We can compute this reasonably efficiently by combining: | |
2115 | * y^PERIOD = 1/2 with precomputed \Sum 1024*y^n {for n <PERIOD} | |
2116 | */ | |
2117 | static u32 __compute_runnable_contrib(u64 n) | |
2118 | { | |
2119 | u32 contrib = 0; | |
2120 | ||
2121 | if (likely(n <= LOAD_AVG_PERIOD)) | |
2122 | return runnable_avg_yN_sum[n]; | |
2123 | else if (unlikely(n >= LOAD_AVG_MAX_N)) | |
2124 | return LOAD_AVG_MAX; | |
2125 | ||
2126 | /* Compute \Sum k^n combining precomputed values for k^i, \Sum k^j */ | |
2127 | do { | |
2128 | contrib /= 2; /* y^LOAD_AVG_PERIOD = 1/2 */ | |
2129 | contrib += runnable_avg_yN_sum[LOAD_AVG_PERIOD]; | |
2130 | ||
2131 | n -= LOAD_AVG_PERIOD; | |
2132 | } while (n > LOAD_AVG_PERIOD); | |
2133 | ||
2134 | contrib = decay_load(contrib, n); | |
2135 | return contrib + runnable_avg_yN_sum[n]; | |
9d85f21c PT |
2136 | } |
2137 | ||
2138 | /* | |
2139 | * We can represent the historical contribution to runnable average as the | |
2140 | * coefficients of a geometric series. To do this we sub-divide our runnable | |
2141 | * history into segments of approximately 1ms (1024us); label the segment that | |
2142 | * occurred N-ms ago p_N, with p_0 corresponding to the current period, e.g. | |
2143 | * | |
2144 | * [<- 1024us ->|<- 1024us ->|<- 1024us ->| ... | |
2145 | * p0 p1 p2 | |
2146 | * (now) (~1ms ago) (~2ms ago) | |
2147 | * | |
2148 | * Let u_i denote the fraction of p_i that the entity was runnable. | |
2149 | * | |
2150 | * We then designate the fractions u_i as our co-efficients, yielding the | |
2151 | * following representation of historical load: | |
2152 | * u_0 + u_1*y + u_2*y^2 + u_3*y^3 + ... | |
2153 | * | |
2154 | * We choose y based on the with of a reasonably scheduling period, fixing: | |
2155 | * y^32 = 0.5 | |
2156 | * | |
2157 | * This means that the contribution to load ~32ms ago (u_32) will be weighted | |
2158 | * approximately half as much as the contribution to load within the last ms | |
2159 | * (u_0). | |
2160 | * | |
2161 | * When a period "rolls over" and we have new u_0`, multiplying the previous | |
2162 | * sum again by y is sufficient to update: | |
2163 | * load_avg = u_0` + y*(u_0 + u_1*y + u_2*y^2 + ... ) | |
2164 | * = u_0 + u_1*y + u_2*y^2 + ... [re-labeling u_i --> u_{i+1}] | |
2165 | */ | |
2166 | static __always_inline int __update_entity_runnable_avg(u64 now, | |
2167 | struct sched_avg *sa, | |
2168 | int runnable) | |
2169 | { | |
5b51f2f8 PT |
2170 | u64 delta, periods; |
2171 | u32 runnable_contrib; | |
9d85f21c PT |
2172 | int delta_w, decayed = 0; |
2173 | ||
2174 | delta = now - sa->last_runnable_update; | |
2175 | /* | |
2176 | * This should only happen when time goes backwards, which it | |
2177 | * unfortunately does during sched clock init when we swap over to TSC. | |
2178 | */ | |
2179 | if ((s64)delta < 0) { | |
2180 | sa->last_runnable_update = now; | |
2181 | return 0; | |
2182 | } | |
2183 | ||
2184 | /* | |
2185 | * Use 1024ns as the unit of measurement since it's a reasonable | |
2186 | * approximation of 1us and fast to compute. | |
2187 | */ | |
2188 | delta >>= 10; | |
2189 | if (!delta) | |
2190 | return 0; | |
2191 | sa->last_runnable_update = now; | |
2192 | ||
2193 | /* delta_w is the amount already accumulated against our next period */ | |
2194 | delta_w = sa->runnable_avg_period % 1024; | |
2195 | if (delta + delta_w >= 1024) { | |
2196 | /* period roll-over */ | |
2197 | decayed = 1; | |
2198 | ||
2199 | /* | |
2200 | * Now that we know we're crossing a period boundary, figure | |
2201 | * out how much from delta we need to complete the current | |
2202 | * period and accrue it. | |
2203 | */ | |
2204 | delta_w = 1024 - delta_w; | |
5b51f2f8 PT |
2205 | if (runnable) |
2206 | sa->runnable_avg_sum += delta_w; | |
2207 | sa->runnable_avg_period += delta_w; | |
2208 | ||
2209 | delta -= delta_w; | |
2210 | ||
2211 | /* Figure out how many additional periods this update spans */ | |
2212 | periods = delta / 1024; | |
2213 | delta %= 1024; | |
2214 | ||
2215 | sa->runnable_avg_sum = decay_load(sa->runnable_avg_sum, | |
2216 | periods + 1); | |
2217 | sa->runnable_avg_period = decay_load(sa->runnable_avg_period, | |
2218 | periods + 1); | |
2219 | ||
2220 | /* Efficiently calculate \sum (1..n_period) 1024*y^i */ | |
2221 | runnable_contrib = __compute_runnable_contrib(periods); | |
2222 | if (runnable) | |
2223 | sa->runnable_avg_sum += runnable_contrib; | |
2224 | sa->runnable_avg_period += runnable_contrib; | |
9d85f21c PT |
2225 | } |
2226 | ||
2227 | /* Remainder of delta accrued against u_0` */ | |
2228 | if (runnable) | |
2229 | sa->runnable_avg_sum += delta; | |
2230 | sa->runnable_avg_period += delta; | |
2231 | ||
2232 | return decayed; | |
2233 | } | |
2234 | ||
9ee474f5 | 2235 | /* Synchronize an entity's decay with its parenting cfs_rq.*/ |
aff3e498 | 2236 | static inline u64 __synchronize_entity_decay(struct sched_entity *se) |
9ee474f5 PT |
2237 | { |
2238 | struct cfs_rq *cfs_rq = cfs_rq_of(se); | |
2239 | u64 decays = atomic64_read(&cfs_rq->decay_counter); | |
2240 | ||
2241 | decays -= se->avg.decay_count; | |
2242 | if (!decays) | |
aff3e498 | 2243 | return 0; |
9ee474f5 PT |
2244 | |
2245 | se->avg.load_avg_contrib = decay_load(se->avg.load_avg_contrib, decays); | |
2246 | se->avg.decay_count = 0; | |
aff3e498 PT |
2247 | |
2248 | return decays; | |
9ee474f5 PT |
2249 | } |
2250 | ||
c566e8e9 PT |
2251 | #ifdef CONFIG_FAIR_GROUP_SCHED |
2252 | static inline void __update_cfs_rq_tg_load_contrib(struct cfs_rq *cfs_rq, | |
2253 | int force_update) | |
2254 | { | |
2255 | struct task_group *tg = cfs_rq->tg; | |
bf5b986e | 2256 | long tg_contrib; |
c566e8e9 PT |
2257 | |
2258 | tg_contrib = cfs_rq->runnable_load_avg + cfs_rq->blocked_load_avg; | |
2259 | tg_contrib -= cfs_rq->tg_load_contrib; | |
2260 | ||
bf5b986e AS |
2261 | if (force_update || abs(tg_contrib) > cfs_rq->tg_load_contrib / 8) { |
2262 | atomic_long_add(tg_contrib, &tg->load_avg); | |
c566e8e9 PT |
2263 | cfs_rq->tg_load_contrib += tg_contrib; |
2264 | } | |
2265 | } | |
8165e145 | 2266 | |
bb17f655 PT |
2267 | /* |
2268 | * Aggregate cfs_rq runnable averages into an equivalent task_group | |
2269 | * representation for computing load contributions. | |
2270 | */ | |
2271 | static inline void __update_tg_runnable_avg(struct sched_avg *sa, | |
2272 | struct cfs_rq *cfs_rq) | |
2273 | { | |
2274 | struct task_group *tg = cfs_rq->tg; | |
2275 | long contrib; | |
2276 | ||
2277 | /* The fraction of a cpu used by this cfs_rq */ | |
85b088e9 | 2278 | contrib = div_u64((u64)sa->runnable_avg_sum << NICE_0_SHIFT, |
bb17f655 PT |
2279 | sa->runnable_avg_period + 1); |
2280 | contrib -= cfs_rq->tg_runnable_contrib; | |
2281 | ||
2282 | if (abs(contrib) > cfs_rq->tg_runnable_contrib / 64) { | |
2283 | atomic_add(contrib, &tg->runnable_avg); | |
2284 | cfs_rq->tg_runnable_contrib += contrib; | |
2285 | } | |
2286 | } | |
2287 | ||
8165e145 PT |
2288 | static inline void __update_group_entity_contrib(struct sched_entity *se) |
2289 | { | |
2290 | struct cfs_rq *cfs_rq = group_cfs_rq(se); | |
2291 | struct task_group *tg = cfs_rq->tg; | |
bb17f655 PT |
2292 | int runnable_avg; |
2293 | ||
8165e145 PT |
2294 | u64 contrib; |
2295 | ||
2296 | contrib = cfs_rq->tg_load_contrib * tg->shares; | |
bf5b986e AS |
2297 | se->avg.load_avg_contrib = div_u64(contrib, |
2298 | atomic_long_read(&tg->load_avg) + 1); | |
bb17f655 PT |
2299 | |
2300 | /* | |
2301 | * For group entities we need to compute a correction term in the case | |
2302 | * that they are consuming <1 cpu so that we would contribute the same | |
2303 | * load as a task of equal weight. | |
2304 | * | |
2305 | * Explicitly co-ordinating this measurement would be expensive, but | |
2306 | * fortunately the sum of each cpus contribution forms a usable | |
2307 | * lower-bound on the true value. | |
2308 | * | |
2309 | * Consider the aggregate of 2 contributions. Either they are disjoint | |
2310 | * (and the sum represents true value) or they are disjoint and we are | |
2311 | * understating by the aggregate of their overlap. | |
2312 | * | |
2313 | * Extending this to N cpus, for a given overlap, the maximum amount we | |
2314 | * understand is then n_i(n_i+1)/2 * w_i where n_i is the number of | |
2315 | * cpus that overlap for this interval and w_i is the interval width. | |
2316 | * | |
2317 | * On a small machine; the first term is well-bounded which bounds the | |
2318 | * total error since w_i is a subset of the period. Whereas on a | |
2319 | * larger machine, while this first term can be larger, if w_i is the | |
2320 | * of consequential size guaranteed to see n_i*w_i quickly converge to | |
2321 | * our upper bound of 1-cpu. | |
2322 | */ | |
2323 | runnable_avg = atomic_read(&tg->runnable_avg); | |
2324 | if (runnable_avg < NICE_0_LOAD) { | |
2325 | se->avg.load_avg_contrib *= runnable_avg; | |
2326 | se->avg.load_avg_contrib >>= NICE_0_SHIFT; | |
2327 | } | |
8165e145 | 2328 | } |
c566e8e9 PT |
2329 | #else |
2330 | static inline void __update_cfs_rq_tg_load_contrib(struct cfs_rq *cfs_rq, | |
2331 | int force_update) {} | |
bb17f655 PT |
2332 | static inline void __update_tg_runnable_avg(struct sched_avg *sa, |
2333 | struct cfs_rq *cfs_rq) {} | |
8165e145 | 2334 | static inline void __update_group_entity_contrib(struct sched_entity *se) {} |
c566e8e9 PT |
2335 | #endif |
2336 | ||
8165e145 PT |
2337 | static inline void __update_task_entity_contrib(struct sched_entity *se) |
2338 | { | |
2339 | u32 contrib; | |
2340 | ||
2341 | /* avoid overflowing a 32-bit type w/ SCHED_LOAD_SCALE */ | |
2342 | contrib = se->avg.runnable_avg_sum * scale_load_down(se->load.weight); | |
2343 | contrib /= (se->avg.runnable_avg_period + 1); | |
2344 | se->avg.load_avg_contrib = scale_load(contrib); | |
2345 | } | |
2346 | ||
2dac754e PT |
2347 | /* Compute the current contribution to load_avg by se, return any delta */ |
2348 | static long __update_entity_load_avg_contrib(struct sched_entity *se) | |
2349 | { | |
2350 | long old_contrib = se->avg.load_avg_contrib; | |
2351 | ||
8165e145 PT |
2352 | if (entity_is_task(se)) { |
2353 | __update_task_entity_contrib(se); | |
2354 | } else { | |
bb17f655 | 2355 | __update_tg_runnable_avg(&se->avg, group_cfs_rq(se)); |
8165e145 PT |
2356 | __update_group_entity_contrib(se); |
2357 | } | |
2dac754e PT |
2358 | |
2359 | return se->avg.load_avg_contrib - old_contrib; | |
2360 | } | |
2361 | ||
9ee474f5 PT |
2362 | static inline void subtract_blocked_load_contrib(struct cfs_rq *cfs_rq, |
2363 | long load_contrib) | |
2364 | { | |
2365 | if (likely(load_contrib < cfs_rq->blocked_load_avg)) | |
2366 | cfs_rq->blocked_load_avg -= load_contrib; | |
2367 | else | |
2368 | cfs_rq->blocked_load_avg = 0; | |
2369 | } | |
2370 | ||
f1b17280 PT |
2371 | static inline u64 cfs_rq_clock_task(struct cfs_rq *cfs_rq); |
2372 | ||
9d85f21c | 2373 | /* Update a sched_entity's runnable average */ |
9ee474f5 PT |
2374 | static inline void update_entity_load_avg(struct sched_entity *se, |
2375 | int update_cfs_rq) | |
9d85f21c | 2376 | { |
2dac754e PT |
2377 | struct cfs_rq *cfs_rq = cfs_rq_of(se); |
2378 | long contrib_delta; | |
f1b17280 | 2379 | u64 now; |
2dac754e | 2380 | |
f1b17280 PT |
2381 | /* |
2382 | * For a group entity we need to use their owned cfs_rq_clock_task() in | |
2383 | * case they are the parent of a throttled hierarchy. | |
2384 | */ | |
2385 | if (entity_is_task(se)) | |
2386 | now = cfs_rq_clock_task(cfs_rq); | |
2387 | else | |
2388 | now = cfs_rq_clock_task(group_cfs_rq(se)); | |
2389 | ||
2390 | if (!__update_entity_runnable_avg(now, &se->avg, se->on_rq)) | |
2dac754e PT |
2391 | return; |
2392 | ||
2393 | contrib_delta = __update_entity_load_avg_contrib(se); | |
9ee474f5 PT |
2394 | |
2395 | if (!update_cfs_rq) | |
2396 | return; | |
2397 | ||
2dac754e PT |
2398 | if (se->on_rq) |
2399 | cfs_rq->runnable_load_avg += contrib_delta; | |
9ee474f5 PT |
2400 | else |
2401 | subtract_blocked_load_contrib(cfs_rq, -contrib_delta); | |
2402 | } | |
2403 | ||
2404 | /* | |
2405 | * Decay the load contributed by all blocked children and account this so that | |
2406 | * their contribution may appropriately discounted when they wake up. | |
2407 | */ | |
aff3e498 | 2408 | static void update_cfs_rq_blocked_load(struct cfs_rq *cfs_rq, int force_update) |
9ee474f5 | 2409 | { |
f1b17280 | 2410 | u64 now = cfs_rq_clock_task(cfs_rq) >> 20; |
9ee474f5 PT |
2411 | u64 decays; |
2412 | ||
2413 | decays = now - cfs_rq->last_decay; | |
aff3e498 | 2414 | if (!decays && !force_update) |
9ee474f5 PT |
2415 | return; |
2416 | ||
2509940f AS |
2417 | if (atomic_long_read(&cfs_rq->removed_load)) { |
2418 | unsigned long removed_load; | |
2419 | removed_load = atomic_long_xchg(&cfs_rq->removed_load, 0); | |
aff3e498 PT |
2420 | subtract_blocked_load_contrib(cfs_rq, removed_load); |
2421 | } | |
9ee474f5 | 2422 | |
aff3e498 PT |
2423 | if (decays) { |
2424 | cfs_rq->blocked_load_avg = decay_load(cfs_rq->blocked_load_avg, | |
2425 | decays); | |
2426 | atomic64_add(decays, &cfs_rq->decay_counter); | |
2427 | cfs_rq->last_decay = now; | |
2428 | } | |
c566e8e9 PT |
2429 | |
2430 | __update_cfs_rq_tg_load_contrib(cfs_rq, force_update); | |
9d85f21c | 2431 | } |
18bf2805 BS |
2432 | |
2433 | static inline void update_rq_runnable_avg(struct rq *rq, int runnable) | |
2434 | { | |
78becc27 | 2435 | __update_entity_runnable_avg(rq_clock_task(rq), &rq->avg, runnable); |
bb17f655 | 2436 | __update_tg_runnable_avg(&rq->avg, &rq->cfs); |
18bf2805 | 2437 | } |
2dac754e PT |
2438 | |
2439 | /* Add the load generated by se into cfs_rq's child load-average */ | |
2440 | static inline void enqueue_entity_load_avg(struct cfs_rq *cfs_rq, | |
9ee474f5 PT |
2441 | struct sched_entity *se, |
2442 | int wakeup) | |
2dac754e | 2443 | { |
aff3e498 PT |
2444 | /* |
2445 | * We track migrations using entity decay_count <= 0, on a wake-up | |
2446 | * migration we use a negative decay count to track the remote decays | |
2447 | * accumulated while sleeping. | |
a75cdaa9 AS |
2448 | * |
2449 | * Newly forked tasks are enqueued with se->avg.decay_count == 0, they | |
2450 | * are seen by enqueue_entity_load_avg() as a migration with an already | |
2451 | * constructed load_avg_contrib. | |
aff3e498 PT |
2452 | */ |
2453 | if (unlikely(se->avg.decay_count <= 0)) { | |
78becc27 | 2454 | se->avg.last_runnable_update = rq_clock_task(rq_of(cfs_rq)); |
aff3e498 PT |
2455 | if (se->avg.decay_count) { |
2456 | /* | |
2457 | * In a wake-up migration we have to approximate the | |
2458 | * time sleeping. This is because we can't synchronize | |
2459 | * clock_task between the two cpus, and it is not | |
2460 | * guaranteed to be read-safe. Instead, we can | |
2461 | * approximate this using our carried decays, which are | |
2462 | * explicitly atomically readable. | |
2463 | */ | |
2464 | se->avg.last_runnable_update -= (-se->avg.decay_count) | |
2465 | << 20; | |
2466 | update_entity_load_avg(se, 0); | |
2467 | /* Indicate that we're now synchronized and on-rq */ | |
2468 | se->avg.decay_count = 0; | |
2469 | } | |
9ee474f5 PT |
2470 | wakeup = 0; |
2471 | } else { | |
9390675a | 2472 | __synchronize_entity_decay(se); |
9ee474f5 PT |
2473 | } |
2474 | ||
aff3e498 PT |
2475 | /* migrated tasks did not contribute to our blocked load */ |
2476 | if (wakeup) { | |
9ee474f5 | 2477 | subtract_blocked_load_contrib(cfs_rq, se->avg.load_avg_contrib); |
aff3e498 PT |
2478 | update_entity_load_avg(se, 0); |
2479 | } | |
9ee474f5 | 2480 | |
2dac754e | 2481 | cfs_rq->runnable_load_avg += se->avg.load_avg_contrib; |
aff3e498 PT |
2482 | /* we force update consideration on load-balancer moves */ |
2483 | update_cfs_rq_blocked_load(cfs_rq, !wakeup); | |
2dac754e PT |
2484 | } |
2485 | ||
9ee474f5 PT |
2486 | /* |
2487 | * Remove se's load from this cfs_rq child load-average, if the entity is | |
2488 | * transitioning to a blocked state we track its projected decay using | |
2489 | * blocked_load_avg. | |
2490 | */ | |
2dac754e | 2491 | static inline void dequeue_entity_load_avg(struct cfs_rq *cfs_rq, |
9ee474f5 PT |
2492 | struct sched_entity *se, |
2493 | int sleep) | |
2dac754e | 2494 | { |
9ee474f5 | 2495 | update_entity_load_avg(se, 1); |
aff3e498 PT |
2496 | /* we force update consideration on load-balancer moves */ |
2497 | update_cfs_rq_blocked_load(cfs_rq, !sleep); | |
9ee474f5 | 2498 | |
2dac754e | 2499 | cfs_rq->runnable_load_avg -= se->avg.load_avg_contrib; |
9ee474f5 PT |
2500 | if (sleep) { |
2501 | cfs_rq->blocked_load_avg += se->avg.load_avg_contrib; | |
2502 | se->avg.decay_count = atomic64_read(&cfs_rq->decay_counter); | |
2503 | } /* migrations, e.g. sleep=0 leave decay_count == 0 */ | |
2dac754e | 2504 | } |
642dbc39 VG |
2505 | |
2506 | /* | |
2507 | * Update the rq's load with the elapsed running time before entering | |
2508 | * idle. if the last scheduled task is not a CFS task, idle_enter will | |
2509 | * be the only way to update the runnable statistic. | |
2510 | */ | |
2511 | void idle_enter_fair(struct rq *this_rq) | |
2512 | { | |
2513 | update_rq_runnable_avg(this_rq, 1); | |
2514 | } | |
2515 | ||
2516 | /* | |
2517 | * Update the rq's load with the elapsed idle time before a task is | |
2518 | * scheduled. if the newly scheduled task is not a CFS task, idle_exit will | |
2519 | * be the only way to update the runnable statistic. | |
2520 | */ | |
2521 | void idle_exit_fair(struct rq *this_rq) | |
2522 | { | |
2523 | update_rq_runnable_avg(this_rq, 0); | |
2524 | } | |
2525 | ||
9d85f21c | 2526 | #else |
9ee474f5 PT |
2527 | static inline void update_entity_load_avg(struct sched_entity *se, |
2528 | int update_cfs_rq) {} | |
18bf2805 | 2529 | static inline void update_rq_runnable_avg(struct rq *rq, int runnable) {} |
2dac754e | 2530 | static inline void enqueue_entity_load_avg(struct cfs_rq *cfs_rq, |
9ee474f5 PT |
2531 | struct sched_entity *se, |
2532 | int wakeup) {} | |
2dac754e | 2533 | static inline void dequeue_entity_load_avg(struct cfs_rq *cfs_rq, |
9ee474f5 PT |
2534 | struct sched_entity *se, |
2535 | int sleep) {} | |
aff3e498 PT |
2536 | static inline void update_cfs_rq_blocked_load(struct cfs_rq *cfs_rq, |
2537 | int force_update) {} | |
9d85f21c PT |
2538 | #endif |
2539 | ||
2396af69 | 2540 | static void enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 2541 | { |
bf0f6f24 | 2542 | #ifdef CONFIG_SCHEDSTATS |
e414314c PZ |
2543 | struct task_struct *tsk = NULL; |
2544 | ||
2545 | if (entity_is_task(se)) | |
2546 | tsk = task_of(se); | |
2547 | ||
41acab88 | 2548 | if (se->statistics.sleep_start) { |
78becc27 | 2549 | u64 delta = rq_clock(rq_of(cfs_rq)) - se->statistics.sleep_start; |
bf0f6f24 IM |
2550 | |
2551 | if ((s64)delta < 0) | |
2552 | delta = 0; | |
2553 | ||
41acab88 LDM |
2554 | if (unlikely(delta > se->statistics.sleep_max)) |
2555 | se->statistics.sleep_max = delta; | |
bf0f6f24 | 2556 | |
8c79a045 | 2557 | se->statistics.sleep_start = 0; |
41acab88 | 2558 | se->statistics.sum_sleep_runtime += delta; |
9745512c | 2559 | |
768d0c27 | 2560 | if (tsk) { |
e414314c | 2561 | account_scheduler_latency(tsk, delta >> 10, 1); |
768d0c27 PZ |
2562 | trace_sched_stat_sleep(tsk, delta); |
2563 | } | |
bf0f6f24 | 2564 | } |
41acab88 | 2565 | if (se->statistics.block_start) { |
78becc27 | 2566 | u64 delta = rq_clock(rq_of(cfs_rq)) - se->statistics.block_start; |
bf0f6f24 IM |
2567 | |
2568 | if ((s64)delta < 0) | |
2569 | delta = 0; | |
2570 | ||
41acab88 LDM |
2571 | if (unlikely(delta > se->statistics.block_max)) |
2572 | se->statistics.block_max = delta; | |
bf0f6f24 | 2573 | |
8c79a045 | 2574 | se->statistics.block_start = 0; |
41acab88 | 2575 | se->statistics.sum_sleep_runtime += delta; |
30084fbd | 2576 | |
e414314c | 2577 | if (tsk) { |
8f0dfc34 | 2578 | if (tsk->in_iowait) { |
41acab88 LDM |
2579 | se->statistics.iowait_sum += delta; |
2580 | se->statistics.iowait_count++; | |
768d0c27 | 2581 | trace_sched_stat_iowait(tsk, delta); |
8f0dfc34 AV |
2582 | } |
2583 | ||
b781a602 AV |
2584 | trace_sched_stat_blocked(tsk, delta); |
2585 | ||
e414314c PZ |
2586 | /* |
2587 | * Blocking time is in units of nanosecs, so shift by | |
2588 | * 20 to get a milliseconds-range estimation of the | |
2589 | * amount of time that the task spent sleeping: | |
2590 | */ | |
2591 | if (unlikely(prof_on == SLEEP_PROFILING)) { | |
2592 | profile_hits(SLEEP_PROFILING, | |
2593 | (void *)get_wchan(tsk), | |
2594 | delta >> 20); | |
2595 | } | |
2596 | account_scheduler_latency(tsk, delta >> 10, 0); | |
30084fbd | 2597 | } |
bf0f6f24 IM |
2598 | } |
2599 | #endif | |
2600 | } | |
2601 | ||
ddc97297 PZ |
2602 | static void check_spread(struct cfs_rq *cfs_rq, struct sched_entity *se) |
2603 | { | |
2604 | #ifdef CONFIG_SCHED_DEBUG | |
2605 | s64 d = se->vruntime - cfs_rq->min_vruntime; | |
2606 | ||
2607 | if (d < 0) | |
2608 | d = -d; | |
2609 | ||
2610 | if (d > 3*sysctl_sched_latency) | |
2611 | schedstat_inc(cfs_rq, nr_spread_over); | |
2612 | #endif | |
2613 | } | |
2614 | ||
aeb73b04 PZ |
2615 | static void |
2616 | place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial) | |
2617 | { | |
1af5f730 | 2618 | u64 vruntime = cfs_rq->min_vruntime; |
94dfb5e7 | 2619 | |
2cb8600e PZ |
2620 | /* |
2621 | * The 'current' period is already promised to the current tasks, | |
2622 | * however the extra weight of the new task will slow them down a | |
2623 | * little, place the new task so that it fits in the slot that | |
2624 | * stays open at the end. | |
2625 | */ | |
94dfb5e7 | 2626 | if (initial && sched_feat(START_DEBIT)) |
f9c0b095 | 2627 | vruntime += sched_vslice(cfs_rq, se); |
aeb73b04 | 2628 | |
a2e7a7eb | 2629 | /* sleeps up to a single latency don't count. */ |
5ca9880c | 2630 | if (!initial) { |
a2e7a7eb | 2631 | unsigned long thresh = sysctl_sched_latency; |
a7be37ac | 2632 | |
a2e7a7eb MG |
2633 | /* |
2634 | * Halve their sleep time's effect, to allow | |
2635 | * for a gentler effect of sleepers: | |
2636 | */ | |
2637 | if (sched_feat(GENTLE_FAIR_SLEEPERS)) | |
2638 | thresh >>= 1; | |
51e0304c | 2639 | |
a2e7a7eb | 2640 | vruntime -= thresh; |
aeb73b04 PZ |
2641 | } |
2642 | ||
b5d9d734 | 2643 | /* ensure we never gain time by being placed backwards. */ |
16c8f1c7 | 2644 | se->vruntime = max_vruntime(se->vruntime, vruntime); |
aeb73b04 PZ |
2645 | } |
2646 | ||
d3d9dc33 PT |
2647 | static void check_enqueue_throttle(struct cfs_rq *cfs_rq); |
2648 | ||
bf0f6f24 | 2649 | static void |
88ec22d3 | 2650 | enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) |
bf0f6f24 | 2651 | { |
88ec22d3 PZ |
2652 | /* |
2653 | * Update the normalized vruntime before updating min_vruntime | |
0fc576d5 | 2654 | * through calling update_curr(). |
88ec22d3 | 2655 | */ |
371fd7e7 | 2656 | if (!(flags & ENQUEUE_WAKEUP) || (flags & ENQUEUE_WAKING)) |
88ec22d3 PZ |
2657 | se->vruntime += cfs_rq->min_vruntime; |
2658 | ||
bf0f6f24 | 2659 | /* |
a2a2d680 | 2660 | * Update run-time statistics of the 'current'. |
bf0f6f24 | 2661 | */ |
b7cc0896 | 2662 | update_curr(cfs_rq); |
f269ae04 | 2663 | enqueue_entity_load_avg(cfs_rq, se, flags & ENQUEUE_WAKEUP); |
17bc14b7 LT |
2664 | account_entity_enqueue(cfs_rq, se); |
2665 | update_cfs_shares(cfs_rq); | |
bf0f6f24 | 2666 | |
88ec22d3 | 2667 | if (flags & ENQUEUE_WAKEUP) { |
aeb73b04 | 2668 | place_entity(cfs_rq, se, 0); |
2396af69 | 2669 | enqueue_sleeper(cfs_rq, se); |
e9acbff6 | 2670 | } |
bf0f6f24 | 2671 | |
d2417e5a | 2672 | update_stats_enqueue(cfs_rq, se); |
ddc97297 | 2673 | check_spread(cfs_rq, se); |
83b699ed SV |
2674 | if (se != cfs_rq->curr) |
2675 | __enqueue_entity(cfs_rq, se); | |
2069dd75 | 2676 | se->on_rq = 1; |
3d4b47b4 | 2677 | |
d3d9dc33 | 2678 | if (cfs_rq->nr_running == 1) { |
3d4b47b4 | 2679 | list_add_leaf_cfs_rq(cfs_rq); |
d3d9dc33 PT |
2680 | check_enqueue_throttle(cfs_rq); |
2681 | } | |
bf0f6f24 IM |
2682 | } |
2683 | ||
2c13c919 | 2684 | static void __clear_buddies_last(struct sched_entity *se) |
2002c695 | 2685 | { |
2c13c919 RR |
2686 | for_each_sched_entity(se) { |
2687 | struct cfs_rq *cfs_rq = cfs_rq_of(se); | |
2688 | if (cfs_rq->last == se) | |
2689 | cfs_rq->last = NULL; | |
2690 | else | |
2691 | break; | |
2692 | } | |
2693 | } | |
2002c695 | 2694 | |
2c13c919 RR |
2695 | static void __clear_buddies_next(struct sched_entity *se) |
2696 | { | |
2697 | for_each_sched_entity(se) { | |
2698 | struct cfs_rq *cfs_rq = cfs_rq_of(se); | |
2699 | if (cfs_rq->next == se) | |
2700 | cfs_rq->next = NULL; | |
2701 | else | |
2702 | break; | |
2703 | } | |
2002c695 PZ |
2704 | } |
2705 | ||
ac53db59 RR |
2706 | static void __clear_buddies_skip(struct sched_entity *se) |
2707 | { | |
2708 | for_each_sched_entity(se) { | |
2709 | struct cfs_rq *cfs_rq = cfs_rq_of(se); | |
2710 | if (cfs_rq->skip == se) | |
2711 | cfs_rq->skip = NULL; | |
2712 | else | |
2713 | break; | |
2714 | } | |
2715 | } | |
2716 | ||
a571bbea PZ |
2717 | static void clear_buddies(struct cfs_rq *cfs_rq, struct sched_entity *se) |
2718 | { | |
2c13c919 RR |
2719 | if (cfs_rq->last == se) |
2720 | __clear_buddies_last(se); | |
2721 | ||
2722 | if (cfs_rq->next == se) | |
2723 | __clear_buddies_next(se); | |
ac53db59 RR |
2724 | |
2725 | if (cfs_rq->skip == se) | |
2726 | __clear_buddies_skip(se); | |
a571bbea PZ |
2727 | } |
2728 | ||
6c16a6dc | 2729 | static __always_inline void return_cfs_rq_runtime(struct cfs_rq *cfs_rq); |
d8b4986d | 2730 | |
bf0f6f24 | 2731 | static void |
371fd7e7 | 2732 | dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) |
bf0f6f24 | 2733 | { |
a2a2d680 DA |
2734 | /* |
2735 | * Update run-time statistics of the 'current'. | |
2736 | */ | |
2737 | update_curr(cfs_rq); | |
17bc14b7 | 2738 | dequeue_entity_load_avg(cfs_rq, se, flags & DEQUEUE_SLEEP); |
a2a2d680 | 2739 | |
19b6a2e3 | 2740 | update_stats_dequeue(cfs_rq, se); |
371fd7e7 | 2741 | if (flags & DEQUEUE_SLEEP) { |
67e9fb2a | 2742 | #ifdef CONFIG_SCHEDSTATS |
bf0f6f24 IM |
2743 | if (entity_is_task(se)) { |
2744 | struct task_struct *tsk = task_of(se); | |
2745 | ||
2746 | if (tsk->state & TASK_INTERRUPTIBLE) | |
78becc27 | 2747 | se->statistics.sleep_start = rq_clock(rq_of(cfs_rq)); |
bf0f6f24 | 2748 | if (tsk->state & TASK_UNINTERRUPTIBLE) |
78becc27 | 2749 | se->statistics.block_start = rq_clock(rq_of(cfs_rq)); |
bf0f6f24 | 2750 | } |
db36cc7d | 2751 | #endif |
67e9fb2a PZ |
2752 | } |
2753 | ||
2002c695 | 2754 | clear_buddies(cfs_rq, se); |
4793241b | 2755 | |
83b699ed | 2756 | if (se != cfs_rq->curr) |
30cfdcfc | 2757 | __dequeue_entity(cfs_rq, se); |
17bc14b7 | 2758 | se->on_rq = 0; |
30cfdcfc | 2759 | account_entity_dequeue(cfs_rq, se); |
88ec22d3 PZ |
2760 | |
2761 | /* | |
2762 | * Normalize the entity after updating the min_vruntime because the | |
2763 | * update can refer to the ->curr item and we need to reflect this | |
2764 | * movement in our normalized position. | |
2765 | */ | |
371fd7e7 | 2766 | if (!(flags & DEQUEUE_SLEEP)) |
88ec22d3 | 2767 | se->vruntime -= cfs_rq->min_vruntime; |
1e876231 | 2768 | |
d8b4986d PT |
2769 | /* return excess runtime on last dequeue */ |
2770 | return_cfs_rq_runtime(cfs_rq); | |
2771 | ||
1e876231 | 2772 | update_min_vruntime(cfs_rq); |
17bc14b7 | 2773 | update_cfs_shares(cfs_rq); |
bf0f6f24 IM |
2774 | } |
2775 | ||
2776 | /* | |
2777 | * Preempt the current task with a newly woken task if needed: | |
2778 | */ | |
7c92e54f | 2779 | static void |
2e09bf55 | 2780 | check_preempt_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr) |
bf0f6f24 | 2781 | { |
11697830 | 2782 | unsigned long ideal_runtime, delta_exec; |
f4cfb33e WX |
2783 | struct sched_entity *se; |
2784 | s64 delta; | |
11697830 | 2785 | |
6d0f0ebd | 2786 | ideal_runtime = sched_slice(cfs_rq, curr); |
11697830 | 2787 | delta_exec = curr->sum_exec_runtime - curr->prev_sum_exec_runtime; |
a9f3e2b5 | 2788 | if (delta_exec > ideal_runtime) { |
bf0f6f24 | 2789 | resched_task(rq_of(cfs_rq)->curr); |
a9f3e2b5 MG |
2790 | /* |
2791 | * The current task ran long enough, ensure it doesn't get | |
2792 | * re-elected due to buddy favours. | |
2793 | */ | |
2794 | clear_buddies(cfs_rq, curr); | |
f685ceac MG |
2795 | return; |
2796 | } | |
2797 | ||
2798 | /* | |
2799 | * Ensure that a task that missed wakeup preemption by a | |
2800 | * narrow margin doesn't have to wait for a full slice. | |
2801 | * This also mitigates buddy induced latencies under load. | |
2802 | */ | |
f685ceac MG |
2803 | if (delta_exec < sysctl_sched_min_granularity) |
2804 | return; | |
2805 | ||
f4cfb33e WX |
2806 | se = __pick_first_entity(cfs_rq); |
2807 | delta = curr->vruntime - se->vruntime; | |
f685ceac | 2808 | |
f4cfb33e WX |
2809 | if (delta < 0) |
2810 | return; | |
d7d82944 | 2811 | |
f4cfb33e WX |
2812 | if (delta > ideal_runtime) |
2813 | resched_task(rq_of(cfs_rq)->curr); | |
bf0f6f24 IM |
2814 | } |
2815 | ||
83b699ed | 2816 | static void |
8494f412 | 2817 | set_next_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 2818 | { |
83b699ed SV |
2819 | /* 'current' is not kept within the tree. */ |
2820 | if (se->on_rq) { | |
2821 | /* | |
2822 | * Any task has to be enqueued before it get to execute on | |
2823 | * a CPU. So account for the time it spent waiting on the | |
2824 | * runqueue. | |
2825 | */ | |
2826 | update_stats_wait_end(cfs_rq, se); | |
2827 | __dequeue_entity(cfs_rq, se); | |
2828 | } | |
2829 | ||
79303e9e | 2830 | update_stats_curr_start(cfs_rq, se); |
429d43bc | 2831 | cfs_rq->curr = se; |
eba1ed4b IM |
2832 | #ifdef CONFIG_SCHEDSTATS |
2833 | /* | |
2834 | * Track our maximum slice length, if the CPU's load is at | |
2835 | * least twice that of our own weight (i.e. dont track it | |
2836 | * when there are only lesser-weight tasks around): | |
2837 | */ | |
495eca49 | 2838 | if (rq_of(cfs_rq)->load.weight >= 2*se->load.weight) { |
41acab88 | 2839 | se->statistics.slice_max = max(se->statistics.slice_max, |
eba1ed4b IM |
2840 | se->sum_exec_runtime - se->prev_sum_exec_runtime); |
2841 | } | |
2842 | #endif | |
4a55b450 | 2843 | se->prev_sum_exec_runtime = se->sum_exec_runtime; |
bf0f6f24 IM |
2844 | } |
2845 | ||
3f3a4904 PZ |
2846 | static int |
2847 | wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se); | |
2848 | ||
ac53db59 RR |
2849 | /* |
2850 | * Pick the next process, keeping these things in mind, in this order: | |
2851 | * 1) keep things fair between processes/task groups | |
2852 | * 2) pick the "next" process, since someone really wants that to run | |
2853 | * 3) pick the "last" process, for cache locality | |
2854 | * 4) do not run the "skip" process, if something else is available | |
2855 | */ | |
f4b6755f | 2856 | static struct sched_entity *pick_next_entity(struct cfs_rq *cfs_rq) |
aa2ac252 | 2857 | { |
ac53db59 | 2858 | struct sched_entity *se = __pick_first_entity(cfs_rq); |
f685ceac | 2859 | struct sched_entity *left = se; |
f4b6755f | 2860 | |
ac53db59 RR |
2861 | /* |
2862 | * Avoid running the skip buddy, if running something else can | |
2863 | * be done without getting too unfair. | |
2864 | */ | |
2865 | if (cfs_rq->skip == se) { | |
2866 | struct sched_entity *second = __pick_next_entity(se); | |
2867 | if (second && wakeup_preempt_entity(second, left) < 1) | |
2868 | se = second; | |
2869 | } | |
aa2ac252 | 2870 | |
f685ceac MG |
2871 | /* |
2872 | * Prefer last buddy, try to return the CPU to a preempted task. | |
2873 | */ | |
2874 | if (cfs_rq->last && wakeup_preempt_entity(cfs_rq->last, left) < 1) | |
2875 | se = cfs_rq->last; | |
2876 | ||
ac53db59 RR |
2877 | /* |
2878 | * Someone really wants this to run. If it's not unfair, run it. | |
2879 | */ | |
2880 | if (cfs_rq->next && wakeup_preempt_entity(cfs_rq->next, left) < 1) | |
2881 | se = cfs_rq->next; | |
2882 | ||
f685ceac | 2883 | clear_buddies(cfs_rq, se); |
4793241b PZ |
2884 | |
2885 | return se; | |
aa2ac252 PZ |
2886 | } |
2887 | ||
d3d9dc33 PT |
2888 | static void check_cfs_rq_runtime(struct cfs_rq *cfs_rq); |
2889 | ||
ab6cde26 | 2890 | static void put_prev_entity(struct cfs_rq *cfs_rq, struct sched_entity *prev) |
bf0f6f24 IM |
2891 | { |
2892 | /* | |
2893 | * If still on the runqueue then deactivate_task() | |
2894 | * was not called and update_curr() has to be done: | |
2895 | */ | |
2896 | if (prev->on_rq) | |
b7cc0896 | 2897 | update_curr(cfs_rq); |
bf0f6f24 | 2898 | |
d3d9dc33 PT |
2899 | /* throttle cfs_rqs exceeding runtime */ |
2900 | check_cfs_rq_runtime(cfs_rq); | |
2901 | ||
ddc97297 | 2902 | check_spread(cfs_rq, prev); |
30cfdcfc | 2903 | if (prev->on_rq) { |
5870db5b | 2904 | update_stats_wait_start(cfs_rq, prev); |
30cfdcfc DA |
2905 | /* Put 'current' back into the tree. */ |
2906 | __enqueue_entity(cfs_rq, prev); | |
9d85f21c | 2907 | /* in !on_rq case, update occurred at dequeue */ |
9ee474f5 | 2908 | update_entity_load_avg(prev, 1); |
30cfdcfc | 2909 | } |
429d43bc | 2910 | cfs_rq->curr = NULL; |
bf0f6f24 IM |
2911 | } |
2912 | ||
8f4d37ec PZ |
2913 | static void |
2914 | entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr, int queued) | |
bf0f6f24 | 2915 | { |
bf0f6f24 | 2916 | /* |
30cfdcfc | 2917 | * Update run-time statistics of the 'current'. |
bf0f6f24 | 2918 | */ |
30cfdcfc | 2919 | update_curr(cfs_rq); |
bf0f6f24 | 2920 | |
9d85f21c PT |
2921 | /* |
2922 | * Ensure that runnable average is periodically updated. | |
2923 | */ | |
9ee474f5 | 2924 | update_entity_load_avg(curr, 1); |
aff3e498 | 2925 | update_cfs_rq_blocked_load(cfs_rq, 1); |
bf0bd948 | 2926 | update_cfs_shares(cfs_rq); |
9d85f21c | 2927 | |
8f4d37ec PZ |
2928 | #ifdef CONFIG_SCHED_HRTICK |
2929 | /* | |
2930 | * queued ticks are scheduled to match the slice, so don't bother | |
2931 | * validating it and just reschedule. | |
2932 | */ | |
983ed7a6 HH |
2933 | if (queued) { |
2934 | resched_task(rq_of(cfs_rq)->curr); | |
2935 | return; | |
2936 | } | |
8f4d37ec PZ |
2937 | /* |
2938 | * don't let the period tick interfere with the hrtick preemption | |
2939 | */ | |
2940 | if (!sched_feat(DOUBLE_TICK) && | |
2941 | hrtimer_active(&rq_of(cfs_rq)->hrtick_timer)) | |
2942 | return; | |
2943 | #endif | |
2944 | ||
2c2efaed | 2945 | if (cfs_rq->nr_running > 1) |
2e09bf55 | 2946 | check_preempt_tick(cfs_rq, curr); |
bf0f6f24 IM |
2947 | } |
2948 | ||
ab84d31e PT |
2949 | |
2950 | /************************************************** | |
2951 | * CFS bandwidth control machinery | |
2952 | */ | |
2953 | ||
2954 | #ifdef CONFIG_CFS_BANDWIDTH | |
029632fb PZ |
2955 | |
2956 | #ifdef HAVE_JUMP_LABEL | |
c5905afb | 2957 | static struct static_key __cfs_bandwidth_used; |
029632fb PZ |
2958 | |
2959 | static inline bool cfs_bandwidth_used(void) | |
2960 | { | |
c5905afb | 2961 | return static_key_false(&__cfs_bandwidth_used); |
029632fb PZ |
2962 | } |
2963 | ||
1ee14e6c | 2964 | void cfs_bandwidth_usage_inc(void) |
029632fb | 2965 | { |
1ee14e6c BS |
2966 | static_key_slow_inc(&__cfs_bandwidth_used); |
2967 | } | |
2968 | ||
2969 | void cfs_bandwidth_usage_dec(void) | |
2970 | { | |
2971 | static_key_slow_dec(&__cfs_bandwidth_used); | |
029632fb PZ |
2972 | } |
2973 | #else /* HAVE_JUMP_LABEL */ | |
2974 | static bool cfs_bandwidth_used(void) | |
2975 | { | |
2976 | return true; | |
2977 | } | |
2978 | ||
1ee14e6c BS |
2979 | void cfs_bandwidth_usage_inc(void) {} |
2980 | void cfs_bandwidth_usage_dec(void) {} | |
029632fb PZ |
2981 | #endif /* HAVE_JUMP_LABEL */ |
2982 | ||
ab84d31e PT |
2983 | /* |
2984 | * default period for cfs group bandwidth. | |
2985 | * default: 0.1s, units: nanoseconds | |
2986 | */ | |
2987 | static inline u64 default_cfs_period(void) | |
2988 | { | |
2989 | return 100000000ULL; | |
2990 | } | |
ec12cb7f PT |
2991 | |
2992 | static inline u64 sched_cfs_bandwidth_slice(void) | |
2993 | { | |
2994 | return (u64)sysctl_sched_cfs_bandwidth_slice * NSEC_PER_USEC; | |
2995 | } | |
2996 | ||
a9cf55b2 PT |
2997 | /* |
2998 | * Replenish runtime according to assigned quota and update expiration time. | |
2999 | * We use sched_clock_cpu directly instead of rq->clock to avoid adding | |
3000 | * additional synchronization around rq->lock. | |
3001 | * | |
3002 | * requires cfs_b->lock | |
3003 | */ | |
029632fb | 3004 | void __refill_cfs_bandwidth_runtime(struct cfs_bandwidth *cfs_b) |
a9cf55b2 PT |
3005 | { |
3006 | u64 now; | |
3007 | ||
3008 | if (cfs_b->quota == RUNTIME_INF) | |
3009 | return; | |
3010 | ||
3011 | now = sched_clock_cpu(smp_processor_id()); | |
3012 | cfs_b->runtime = cfs_b->quota; | |
3013 | cfs_b->runtime_expires = now + ktime_to_ns(cfs_b->period); | |
3014 | } | |
3015 | ||
029632fb PZ |
3016 | static inline struct cfs_bandwidth *tg_cfs_bandwidth(struct task_group *tg) |
3017 | { | |
3018 | return &tg->cfs_bandwidth; | |
3019 | } | |
3020 | ||
f1b17280 PT |
3021 | /* rq->task_clock normalized against any time this cfs_rq has spent throttled */ |
3022 | static inline u64 cfs_rq_clock_task(struct cfs_rq *cfs_rq) | |
3023 | { | |
3024 | if (unlikely(cfs_rq->throttle_count)) | |
3025 | return cfs_rq->throttled_clock_task; | |
3026 | ||
78becc27 | 3027 | return rq_clock_task(rq_of(cfs_rq)) - cfs_rq->throttled_clock_task_time; |
f1b17280 PT |
3028 | } |
3029 | ||
85dac906 PT |
3030 | /* returns 0 on failure to allocate runtime */ |
3031 | static int assign_cfs_rq_runtime(struct cfs_rq *cfs_rq) | |
ec12cb7f PT |
3032 | { |
3033 | struct task_group *tg = cfs_rq->tg; | |
3034 | struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(tg); | |
a9cf55b2 | 3035 | u64 amount = 0, min_amount, expires; |
ec12cb7f PT |
3036 | |
3037 | /* note: this is a positive sum as runtime_remaining <= 0 */ | |
3038 | min_amount = sched_cfs_bandwidth_slice() - cfs_rq->runtime_remaining; | |
3039 | ||
3040 | raw_spin_lock(&cfs_b->lock); | |
3041 | if (cfs_b->quota == RUNTIME_INF) | |
3042 | amount = min_amount; | |
58088ad0 | 3043 | else { |
a9cf55b2 PT |
3044 | /* |
3045 | * If the bandwidth pool has become inactive, then at least one | |
3046 | * period must have elapsed since the last consumption. | |
3047 | * Refresh the global state and ensure bandwidth timer becomes | |
3048 | * active. | |
3049 | */ | |
3050 | if (!cfs_b->timer_active) { | |
3051 | __refill_cfs_bandwidth_runtime(cfs_b); | |
58088ad0 | 3052 | __start_cfs_bandwidth(cfs_b); |
a9cf55b2 | 3053 | } |
58088ad0 PT |
3054 | |
3055 | if (cfs_b->runtime > 0) { | |
3056 | amount = min(cfs_b->runtime, min_amount); | |
3057 | cfs_b->runtime -= amount; | |
3058 | cfs_b->idle = 0; | |
3059 | } | |
ec12cb7f | 3060 | } |
a9cf55b2 | 3061 | expires = cfs_b->runtime_expires; |
ec12cb7f PT |
3062 | raw_spin_unlock(&cfs_b->lock); |
3063 | ||
3064 | cfs_rq->runtime_remaining += amount; | |
a9cf55b2 PT |
3065 | /* |
3066 | * we may have advanced our local expiration to account for allowed | |
3067 | * spread between our sched_clock and the one on which runtime was | |
3068 | * issued. | |
3069 | */ | |
3070 | if ((s64)(expires - cfs_rq->runtime_expires) > 0) | |
3071 | cfs_rq->runtime_expires = expires; | |
85dac906 PT |
3072 | |
3073 | return cfs_rq->runtime_remaining > 0; | |
ec12cb7f PT |
3074 | } |
3075 | ||
a9cf55b2 PT |
3076 | /* |
3077 | * Note: This depends on the synchronization provided by sched_clock and the | |
3078 | * fact that rq->clock snapshots this value. | |
3079 | */ | |
3080 | static void expire_cfs_rq_runtime(struct cfs_rq *cfs_rq) | |
ec12cb7f | 3081 | { |
a9cf55b2 | 3082 | struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg); |
a9cf55b2 PT |
3083 | |
3084 | /* if the deadline is ahead of our clock, nothing to do */ | |
78becc27 | 3085 | if (likely((s64)(rq_clock(rq_of(cfs_rq)) - cfs_rq->runtime_expires) < 0)) |
ec12cb7f PT |
3086 | return; |
3087 | ||
a9cf55b2 PT |
3088 | if (cfs_rq->runtime_remaining < 0) |
3089 | return; | |
3090 | ||
3091 | /* | |
3092 | * If the local deadline has passed we have to consider the | |
3093 | * possibility that our sched_clock is 'fast' and the global deadline | |
3094 | * has not truly expired. | |
3095 | * | |
3096 | * Fortunately we can check determine whether this the case by checking | |
3097 | * whether the global deadline has advanced. | |
3098 | */ | |
3099 | ||
3100 | if ((s64)(cfs_rq->runtime_expires - cfs_b->runtime_expires) >= 0) { | |
3101 | /* extend local deadline, drift is bounded above by 2 ticks */ | |
3102 | cfs_rq->runtime_expires += TICK_NSEC; | |
3103 | } else { | |
3104 | /* global deadline is ahead, expiration has passed */ | |
3105 | cfs_rq->runtime_remaining = 0; | |
3106 | } | |
3107 | } | |
3108 | ||
9dbdb155 | 3109 | static void __account_cfs_rq_runtime(struct cfs_rq *cfs_rq, u64 delta_exec) |
a9cf55b2 PT |
3110 | { |
3111 | /* dock delta_exec before expiring quota (as it could span periods) */ | |
ec12cb7f | 3112 | cfs_rq->runtime_remaining -= delta_exec; |
a9cf55b2 PT |
3113 | expire_cfs_rq_runtime(cfs_rq); |
3114 | ||
3115 | if (likely(cfs_rq->runtime_remaining > 0)) | |
ec12cb7f PT |
3116 | return; |
3117 | ||
85dac906 PT |
3118 | /* |
3119 | * if we're unable to extend our runtime we resched so that the active | |
3120 | * hierarchy can be throttled | |
3121 | */ | |
3122 | if (!assign_cfs_rq_runtime(cfs_rq) && likely(cfs_rq->curr)) | |
3123 | resched_task(rq_of(cfs_rq)->curr); | |
ec12cb7f PT |
3124 | } |
3125 | ||
6c16a6dc | 3126 | static __always_inline |
9dbdb155 | 3127 | void account_cfs_rq_runtime(struct cfs_rq *cfs_rq, u64 delta_exec) |
ec12cb7f | 3128 | { |
56f570e5 | 3129 | if (!cfs_bandwidth_used() || !cfs_rq->runtime_enabled) |
ec12cb7f PT |
3130 | return; |
3131 | ||
3132 | __account_cfs_rq_runtime(cfs_rq, delta_exec); | |
3133 | } | |
3134 | ||
85dac906 PT |
3135 | static inline int cfs_rq_throttled(struct cfs_rq *cfs_rq) |
3136 | { | |
56f570e5 | 3137 | return cfs_bandwidth_used() && cfs_rq->throttled; |
85dac906 PT |
3138 | } |
3139 | ||
64660c86 PT |
3140 | /* check whether cfs_rq, or any parent, is throttled */ |
3141 | static inline int throttled_hierarchy(struct cfs_rq *cfs_rq) | |
3142 | { | |
56f570e5 | 3143 | return cfs_bandwidth_used() && cfs_rq->throttle_count; |
64660c86 PT |
3144 | } |
3145 | ||
3146 | /* | |
3147 | * Ensure that neither of the group entities corresponding to src_cpu or | |
3148 | * dest_cpu are members of a throttled hierarchy when performing group | |
3149 | * load-balance operations. | |
3150 | */ | |
3151 | static inline int throttled_lb_pair(struct task_group *tg, | |
3152 | int src_cpu, int dest_cpu) | |
3153 | { | |
3154 | struct cfs_rq *src_cfs_rq, *dest_cfs_rq; | |
3155 | ||
3156 | src_cfs_rq = tg->cfs_rq[src_cpu]; | |
3157 | dest_cfs_rq = tg->cfs_rq[dest_cpu]; | |
3158 | ||
3159 | return throttled_hierarchy(src_cfs_rq) || | |
3160 | throttled_hierarchy(dest_cfs_rq); | |
3161 | } | |
3162 | ||
3163 | /* updated child weight may affect parent so we have to do this bottom up */ | |
3164 | static int tg_unthrottle_up(struct task_group *tg, void *data) | |
3165 | { | |
3166 | struct rq *rq = data; | |
3167 | struct cfs_rq *cfs_rq = tg->cfs_rq[cpu_of(rq)]; | |
3168 | ||
3169 | cfs_rq->throttle_count--; | |
3170 | #ifdef CONFIG_SMP | |
3171 | if (!cfs_rq->throttle_count) { | |
f1b17280 | 3172 | /* adjust cfs_rq_clock_task() */ |
78becc27 | 3173 | cfs_rq->throttled_clock_task_time += rq_clock_task(rq) - |
f1b17280 | 3174 | cfs_rq->throttled_clock_task; |
64660c86 PT |
3175 | } |
3176 | #endif | |
3177 | ||
3178 | return 0; | |
3179 | } | |
3180 | ||
3181 | static int tg_throttle_down(struct task_group *tg, void *data) | |
3182 | { | |
3183 | struct rq *rq = data; | |
3184 | struct cfs_rq *cfs_rq = tg->cfs_rq[cpu_of(rq)]; | |
3185 | ||
82958366 PT |
3186 | /* group is entering throttled state, stop time */ |
3187 | if (!cfs_rq->throttle_count) | |
78becc27 | 3188 | cfs_rq->throttled_clock_task = rq_clock_task(rq); |
64660c86 PT |
3189 | cfs_rq->throttle_count++; |
3190 | ||
3191 | return 0; | |
3192 | } | |
3193 | ||
d3d9dc33 | 3194 | static void throttle_cfs_rq(struct cfs_rq *cfs_rq) |
85dac906 PT |
3195 | { |
3196 | struct rq *rq = rq_of(cfs_rq); | |
3197 | struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg); | |
3198 | struct sched_entity *se; | |
3199 | long task_delta, dequeue = 1; | |
3200 | ||
3201 | se = cfs_rq->tg->se[cpu_of(rq_of(cfs_rq))]; | |
3202 | ||
f1b17280 | 3203 | /* freeze hierarchy runnable averages while throttled */ |
64660c86 PT |
3204 | rcu_read_lock(); |
3205 | walk_tg_tree_from(cfs_rq->tg, tg_throttle_down, tg_nop, (void *)rq); | |
3206 | rcu_read_unlock(); | |
85dac906 PT |
3207 | |
3208 | task_delta = cfs_rq->h_nr_running; | |
3209 | for_each_sched_entity(se) { | |
3210 | struct cfs_rq *qcfs_rq = cfs_rq_of(se); | |
3211 | /* throttled entity or throttle-on-deactivate */ | |
3212 | if (!se->on_rq) | |
3213 | break; | |
3214 | ||
3215 | if (dequeue) | |
3216 | dequeue_entity(qcfs_rq, se, DEQUEUE_SLEEP); | |
3217 | qcfs_rq->h_nr_running -= task_delta; | |
3218 | ||
3219 | if (qcfs_rq->load.weight) | |
3220 | dequeue = 0; | |
3221 | } | |
3222 | ||
3223 | if (!se) | |
3224 | rq->nr_running -= task_delta; | |
3225 | ||
3226 | cfs_rq->throttled = 1; | |
78becc27 | 3227 | cfs_rq->throttled_clock = rq_clock(rq); |
85dac906 PT |
3228 | raw_spin_lock(&cfs_b->lock); |
3229 | list_add_tail_rcu(&cfs_rq->throttled_list, &cfs_b->throttled_cfs_rq); | |
f9f9ffc2 BS |
3230 | if (!cfs_b->timer_active) |
3231 | __start_cfs_bandwidth(cfs_b); | |
85dac906 PT |
3232 | raw_spin_unlock(&cfs_b->lock); |
3233 | } | |
3234 | ||
029632fb | 3235 | void unthrottle_cfs_rq(struct cfs_rq *cfs_rq) |
671fd9da PT |
3236 | { |
3237 | struct rq *rq = rq_of(cfs_rq); | |
3238 | struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg); | |
3239 | struct sched_entity *se; | |
3240 | int enqueue = 1; | |
3241 | long task_delta; | |
3242 | ||
22b958d8 | 3243 | se = cfs_rq->tg->se[cpu_of(rq)]; |
671fd9da PT |
3244 | |
3245 | cfs_rq->throttled = 0; | |
1a55af2e FW |
3246 | |
3247 | update_rq_clock(rq); | |
3248 | ||
671fd9da | 3249 | raw_spin_lock(&cfs_b->lock); |
78becc27 | 3250 | cfs_b->throttled_time += rq_clock(rq) - cfs_rq->throttled_clock; |
671fd9da PT |
3251 | list_del_rcu(&cfs_rq->throttled_list); |
3252 | raw_spin_unlock(&cfs_b->lock); | |
3253 | ||
64660c86 PT |
3254 | /* update hierarchical throttle state */ |
3255 | walk_tg_tree_from(cfs_rq->tg, tg_nop, tg_unthrottle_up, (void *)rq); | |
3256 | ||
671fd9da PT |
3257 | if (!cfs_rq->load.weight) |
3258 | return; | |
3259 | ||
3260 | task_delta = cfs_rq->h_nr_running; | |
3261 | for_each_sched_entity(se) { | |
3262 | if (se->on_rq) | |
3263 | enqueue = 0; | |
3264 | ||
3265 | cfs_rq = cfs_rq_of(se); | |
3266 | if (enqueue) | |
3267 | enqueue_entity(cfs_rq, se, ENQUEUE_WAKEUP); | |
3268 | cfs_rq->h_nr_running += task_delta; | |
3269 | ||
3270 | if (cfs_rq_throttled(cfs_rq)) | |
3271 | break; | |
3272 | } | |
3273 | ||
3274 | if (!se) | |
3275 | rq->nr_running += task_delta; | |
3276 | ||
3277 | /* determine whether we need to wake up potentially idle cpu */ | |
3278 | if (rq->curr == rq->idle && rq->cfs.nr_running) | |
3279 | resched_task(rq->curr); | |
3280 | } | |
3281 | ||
3282 | static u64 distribute_cfs_runtime(struct cfs_bandwidth *cfs_b, | |
3283 | u64 remaining, u64 expires) | |
3284 | { | |
3285 | struct cfs_rq *cfs_rq; | |
3286 | u64 runtime = remaining; | |
3287 | ||
3288 | rcu_read_lock(); | |
3289 | list_for_each_entry_rcu(cfs_rq, &cfs_b->throttled_cfs_rq, | |
3290 | throttled_list) { | |
3291 | struct rq *rq = rq_of(cfs_rq); | |
3292 | ||
3293 | raw_spin_lock(&rq->lock); | |
3294 | if (!cfs_rq_throttled(cfs_rq)) | |
3295 | goto next; | |
3296 | ||
3297 | runtime = -cfs_rq->runtime_remaining + 1; | |
3298 | if (runtime > remaining) | |
3299 | runtime = remaining; | |
3300 | remaining -= runtime; | |
3301 | ||
3302 | cfs_rq->runtime_remaining += runtime; | |
3303 | cfs_rq->runtime_expires = expires; | |
3304 | ||
3305 | /* we check whether we're throttled above */ | |
3306 | if (cfs_rq->runtime_remaining > 0) | |
3307 | unthrottle_cfs_rq(cfs_rq); | |
3308 | ||
3309 | next: | |
3310 | raw_spin_unlock(&rq->lock); | |
3311 | ||
3312 | if (!remaining) | |
3313 | break; | |
3314 | } | |
3315 | rcu_read_unlock(); | |
3316 | ||
3317 | return remaining; | |
3318 | } | |
3319 | ||
58088ad0 PT |
3320 | /* |
3321 | * Responsible for refilling a task_group's bandwidth and unthrottling its | |
3322 | * cfs_rqs as appropriate. If there has been no activity within the last | |
3323 | * period the timer is deactivated until scheduling resumes; cfs_b->idle is | |
3324 | * used to track this state. | |
3325 | */ | |
3326 | static int do_sched_cfs_period_timer(struct cfs_bandwidth *cfs_b, int overrun) | |
3327 | { | |
671fd9da PT |
3328 | u64 runtime, runtime_expires; |
3329 | int idle = 1, throttled; | |
58088ad0 PT |
3330 | |
3331 | raw_spin_lock(&cfs_b->lock); | |
3332 | /* no need to continue the timer with no bandwidth constraint */ | |
3333 | if (cfs_b->quota == RUNTIME_INF) | |
3334 | goto out_unlock; | |
3335 | ||
671fd9da PT |
3336 | throttled = !list_empty(&cfs_b->throttled_cfs_rq); |
3337 | /* idle depends on !throttled (for the case of a large deficit) */ | |
3338 | idle = cfs_b->idle && !throttled; | |
e8da1b18 | 3339 | cfs_b->nr_periods += overrun; |
671fd9da | 3340 | |
a9cf55b2 PT |
3341 | /* if we're going inactive then everything else can be deferred */ |
3342 | if (idle) | |
3343 | goto out_unlock; | |
3344 | ||
927b54fc BS |
3345 | /* |
3346 | * if we have relooped after returning idle once, we need to update our | |
3347 | * status as actually running, so that other cpus doing | |
3348 | * __start_cfs_bandwidth will stop trying to cancel us. | |
3349 | */ | |
3350 | cfs_b->timer_active = 1; | |
3351 | ||
a9cf55b2 PT |
3352 | __refill_cfs_bandwidth_runtime(cfs_b); |
3353 | ||
671fd9da PT |
3354 | if (!throttled) { |
3355 | /* mark as potentially idle for the upcoming period */ | |
3356 | cfs_b->idle = 1; | |
3357 | goto out_unlock; | |
3358 | } | |
3359 | ||
e8da1b18 NR |
3360 | /* account preceding periods in which throttling occurred */ |
3361 | cfs_b->nr_throttled += overrun; | |
3362 | ||
671fd9da PT |
3363 | /* |
3364 | * There are throttled entities so we must first use the new bandwidth | |
3365 | * to unthrottle them before making it generally available. This | |
3366 | * ensures that all existing debts will be paid before a new cfs_rq is | |
3367 | * allowed to run. | |
3368 | */ | |
3369 | runtime = cfs_b->runtime; | |
3370 | runtime_expires = cfs_b->runtime_expires; | |
3371 | cfs_b->runtime = 0; | |
3372 | ||
3373 | /* | |
3374 | * This check is repeated as we are holding onto the new bandwidth | |
3375 | * while we unthrottle. This can potentially race with an unthrottled | |
3376 | * group trying to acquire new bandwidth from the global pool. | |
3377 | */ | |
3378 | while (throttled && runtime > 0) { | |
3379 | raw_spin_unlock(&cfs_b->lock); | |
3380 | /* we can't nest cfs_b->lock while distributing bandwidth */ | |
3381 | runtime = distribute_cfs_runtime(cfs_b, runtime, | |
3382 | runtime_expires); | |
3383 | raw_spin_lock(&cfs_b->lock); | |
3384 | ||
3385 | throttled = !list_empty(&cfs_b->throttled_cfs_rq); | |
3386 | } | |
58088ad0 | 3387 | |
671fd9da PT |
3388 | /* return (any) remaining runtime */ |
3389 | cfs_b->runtime = runtime; | |
3390 | /* | |
3391 | * While we are ensured activity in the period following an | |
3392 | * unthrottle, this also covers the case in which the new bandwidth is | |
3393 | * insufficient to cover the existing bandwidth deficit. (Forcing the | |
3394 | * timer to remain active while there are any throttled entities.) | |
3395 | */ | |
3396 | cfs_b->idle = 0; | |
58088ad0 PT |
3397 | out_unlock: |
3398 | if (idle) | |
3399 | cfs_b->timer_active = 0; | |
3400 | raw_spin_unlock(&cfs_b->lock); | |
3401 | ||
3402 | return idle; | |
3403 | } | |
d3d9dc33 | 3404 | |
d8b4986d PT |
3405 | /* a cfs_rq won't donate quota below this amount */ |
3406 | static const u64 min_cfs_rq_runtime = 1 * NSEC_PER_MSEC; | |
3407 | /* minimum remaining period time to redistribute slack quota */ | |
3408 | static const u64 min_bandwidth_expiration = 2 * NSEC_PER_MSEC; | |
3409 | /* how long we wait to gather additional slack before distributing */ | |
3410 | static const u64 cfs_bandwidth_slack_period = 5 * NSEC_PER_MSEC; | |
3411 | ||
db06e78c BS |
3412 | /* |
3413 | * Are we near the end of the current quota period? | |
3414 | * | |
3415 | * Requires cfs_b->lock for hrtimer_expires_remaining to be safe against the | |
3416 | * hrtimer base being cleared by __hrtimer_start_range_ns. In the case of | |
3417 | * migrate_hrtimers, base is never cleared, so we are fine. | |
3418 | */ | |
d8b4986d PT |
3419 | static int runtime_refresh_within(struct cfs_bandwidth *cfs_b, u64 min_expire) |
3420 | { | |
3421 | struct hrtimer *refresh_timer = &cfs_b->period_timer; | |
3422 | u64 remaining; | |
3423 | ||
3424 | /* if the call-back is running a quota refresh is already occurring */ | |
3425 | if (hrtimer_callback_running(refresh_timer)) | |
3426 | return 1; | |
3427 | ||
3428 | /* is a quota refresh about to occur? */ | |
3429 | remaining = ktime_to_ns(hrtimer_expires_remaining(refresh_timer)); | |
3430 | if (remaining < min_expire) | |
3431 | return 1; | |
3432 | ||
3433 | return 0; | |
3434 | } | |
3435 | ||
3436 | static void start_cfs_slack_bandwidth(struct cfs_bandwidth *cfs_b) | |
3437 | { | |
3438 | u64 min_left = cfs_bandwidth_slack_period + min_bandwidth_expiration; | |
3439 | ||
3440 | /* if there's a quota refresh soon don't bother with slack */ | |
3441 | if (runtime_refresh_within(cfs_b, min_left)) | |
3442 | return; | |
3443 | ||
3444 | start_bandwidth_timer(&cfs_b->slack_timer, | |
3445 | ns_to_ktime(cfs_bandwidth_slack_period)); | |
3446 | } | |
3447 | ||
3448 | /* we know any runtime found here is valid as update_curr() precedes return */ | |
3449 | static void __return_cfs_rq_runtime(struct cfs_rq *cfs_rq) | |
3450 | { | |
3451 | struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg); | |
3452 | s64 slack_runtime = cfs_rq->runtime_remaining - min_cfs_rq_runtime; | |
3453 | ||
3454 | if (slack_runtime <= 0) | |
3455 | return; | |
3456 | ||
3457 | raw_spin_lock(&cfs_b->lock); | |
3458 | if (cfs_b->quota != RUNTIME_INF && | |
3459 | cfs_rq->runtime_expires == cfs_b->runtime_expires) { | |
3460 | cfs_b->runtime += slack_runtime; | |
3461 | ||
3462 | /* we are under rq->lock, defer unthrottling using a timer */ | |
3463 | if (cfs_b->runtime > sched_cfs_bandwidth_slice() && | |
3464 | !list_empty(&cfs_b->throttled_cfs_rq)) | |
3465 | start_cfs_slack_bandwidth(cfs_b); | |
3466 | } | |
3467 | raw_spin_unlock(&cfs_b->lock); | |
3468 | ||
3469 | /* even if it's not valid for return we don't want to try again */ | |
3470 | cfs_rq->runtime_remaining -= slack_runtime; | |
3471 | } | |
3472 | ||
3473 | static __always_inline void return_cfs_rq_runtime(struct cfs_rq *cfs_rq) | |
3474 | { | |
56f570e5 PT |
3475 | if (!cfs_bandwidth_used()) |
3476 | return; | |
3477 | ||
fccfdc6f | 3478 | if (!cfs_rq->runtime_enabled || cfs_rq->nr_running) |
d8b4986d PT |
3479 | return; |
3480 | ||
3481 | __return_cfs_rq_runtime(cfs_rq); | |
3482 | } | |
3483 | ||
3484 | /* | |
3485 | * This is done with a timer (instead of inline with bandwidth return) since | |
3486 | * it's necessary to juggle rq->locks to unthrottle their respective cfs_rqs. | |
3487 | */ | |
3488 | static void do_sched_cfs_slack_timer(struct cfs_bandwidth *cfs_b) | |
3489 | { | |
3490 | u64 runtime = 0, slice = sched_cfs_bandwidth_slice(); | |
3491 | u64 expires; | |
3492 | ||
3493 | /* confirm we're still not at a refresh boundary */ | |
db06e78c BS |
3494 | raw_spin_lock(&cfs_b->lock); |
3495 | if (runtime_refresh_within(cfs_b, min_bandwidth_expiration)) { | |
3496 | raw_spin_unlock(&cfs_b->lock); | |
d8b4986d | 3497 | return; |
db06e78c | 3498 | } |
d8b4986d | 3499 | |
d8b4986d PT |
3500 | if (cfs_b->quota != RUNTIME_INF && cfs_b->runtime > slice) { |
3501 | runtime = cfs_b->runtime; | |
3502 | cfs_b->runtime = 0; | |
3503 | } | |
3504 | expires = cfs_b->runtime_expires; | |
3505 | raw_spin_unlock(&cfs_b->lock); | |
3506 | ||
3507 | if (!runtime) | |
3508 | return; | |
3509 | ||
3510 | runtime = distribute_cfs_runtime(cfs_b, runtime, expires); | |
3511 | ||
3512 | raw_spin_lock(&cfs_b->lock); | |
3513 | if (expires == cfs_b->runtime_expires) | |
3514 | cfs_b->runtime = runtime; | |
3515 | raw_spin_unlock(&cfs_b->lock); | |
3516 | } | |
3517 | ||
d3d9dc33 PT |
3518 | /* |
3519 | * When a group wakes up we want to make sure that its quota is not already | |
3520 | * expired/exceeded, otherwise it may be allowed to steal additional ticks of | |
3521 | * runtime as update_curr() throttling can not not trigger until it's on-rq. | |
3522 | */ | |
3523 | static void check_enqueue_throttle(struct cfs_rq *cfs_rq) | |
3524 | { | |
56f570e5 PT |
3525 | if (!cfs_bandwidth_used()) |
3526 | return; | |
3527 | ||
d3d9dc33 PT |
3528 | /* an active group must be handled by the update_curr()->put() path */ |
3529 | if (!cfs_rq->runtime_enabled || cfs_rq->curr) | |
3530 | return; | |
3531 | ||
3532 | /* ensure the group is not already throttled */ | |
3533 | if (cfs_rq_throttled(cfs_rq)) | |
3534 | return; | |
3535 | ||
3536 | /* update runtime allocation */ | |
3537 | account_cfs_rq_runtime(cfs_rq, 0); | |
3538 | if (cfs_rq->runtime_remaining <= 0) | |
3539 | throttle_cfs_rq(cfs_rq); | |
3540 | } | |
3541 | ||
3542 | /* conditionally throttle active cfs_rq's from put_prev_entity() */ | |
3543 | static void check_cfs_rq_runtime(struct cfs_rq *cfs_rq) | |
3544 | { | |
56f570e5 PT |
3545 | if (!cfs_bandwidth_used()) |
3546 | return; | |
3547 | ||
d3d9dc33 PT |
3548 | if (likely(!cfs_rq->runtime_enabled || cfs_rq->runtime_remaining > 0)) |
3549 | return; | |
3550 | ||
3551 | /* | |
3552 | * it's possible for a throttled entity to be forced into a running | |
3553 | * state (e.g. set_curr_task), in this case we're finished. | |
3554 | */ | |
3555 | if (cfs_rq_throttled(cfs_rq)) | |
3556 | return; | |
3557 | ||
3558 | throttle_cfs_rq(cfs_rq); | |
3559 | } | |
029632fb | 3560 | |
029632fb PZ |
3561 | static enum hrtimer_restart sched_cfs_slack_timer(struct hrtimer *timer) |
3562 | { | |
3563 | struct cfs_bandwidth *cfs_b = | |
3564 | container_of(timer, struct cfs_bandwidth, slack_timer); | |
3565 | do_sched_cfs_slack_timer(cfs_b); | |
3566 | ||
3567 | return HRTIMER_NORESTART; | |
3568 | } | |
3569 | ||
3570 | static enum hrtimer_restart sched_cfs_period_timer(struct hrtimer *timer) | |
3571 | { | |
3572 | struct cfs_bandwidth *cfs_b = | |
3573 | container_of(timer, struct cfs_bandwidth, period_timer); | |
3574 | ktime_t now; | |
3575 | int overrun; | |
3576 | int idle = 0; | |
3577 | ||
3578 | for (;;) { | |
3579 | now = hrtimer_cb_get_time(timer); | |
3580 | overrun = hrtimer_forward(timer, now, cfs_b->period); | |
3581 | ||
3582 | if (!overrun) | |
3583 | break; | |
3584 | ||
3585 | idle = do_sched_cfs_period_timer(cfs_b, overrun); | |
3586 | } | |
3587 | ||
3588 | return idle ? HRTIMER_NORESTART : HRTIMER_RESTART; | |
3589 | } | |
3590 | ||
3591 | void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b) | |
3592 | { | |
3593 | raw_spin_lock_init(&cfs_b->lock); | |
3594 | cfs_b->runtime = 0; | |
3595 | cfs_b->quota = RUNTIME_INF; | |
3596 | cfs_b->period = ns_to_ktime(default_cfs_period()); | |
3597 | ||
3598 | INIT_LIST_HEAD(&cfs_b->throttled_cfs_rq); | |
3599 | hrtimer_init(&cfs_b->period_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); | |
3600 | cfs_b->period_timer.function = sched_cfs_period_timer; | |
3601 | hrtimer_init(&cfs_b->slack_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); | |
3602 | cfs_b->slack_timer.function = sched_cfs_slack_timer; | |
3603 | } | |
3604 | ||
3605 | static void init_cfs_rq_runtime(struct cfs_rq *cfs_rq) | |
3606 | { | |
3607 | cfs_rq->runtime_enabled = 0; | |
3608 | INIT_LIST_HEAD(&cfs_rq->throttled_list); | |
3609 | } | |
3610 | ||
3611 | /* requires cfs_b->lock, may release to reprogram timer */ | |
3612 | void __start_cfs_bandwidth(struct cfs_bandwidth *cfs_b) | |
3613 | { | |
3614 | /* | |
3615 | * The timer may be active because we're trying to set a new bandwidth | |
3616 | * period or because we're racing with the tear-down path | |
3617 | * (timer_active==0 becomes visible before the hrtimer call-back | |
3618 | * terminates). In either case we ensure that it's re-programmed | |
3619 | */ | |
927b54fc BS |
3620 | while (unlikely(hrtimer_active(&cfs_b->period_timer)) && |
3621 | hrtimer_try_to_cancel(&cfs_b->period_timer) < 0) { | |
3622 | /* bounce the lock to allow do_sched_cfs_period_timer to run */ | |
029632fb | 3623 | raw_spin_unlock(&cfs_b->lock); |
927b54fc | 3624 | cpu_relax(); |
029632fb PZ |
3625 | raw_spin_lock(&cfs_b->lock); |
3626 | /* if someone else restarted the timer then we're done */ | |
3627 | if (cfs_b->timer_active) | |
3628 | return; | |
3629 | } | |
3630 | ||
3631 | cfs_b->timer_active = 1; | |
3632 | start_bandwidth_timer(&cfs_b->period_timer, cfs_b->period); | |
3633 | } | |
3634 | ||
3635 | static void destroy_cfs_bandwidth(struct cfs_bandwidth *cfs_b) | |
3636 | { | |
3637 | hrtimer_cancel(&cfs_b->period_timer); | |
3638 | hrtimer_cancel(&cfs_b->slack_timer); | |
3639 | } | |
3640 | ||
38dc3348 | 3641 | static void __maybe_unused unthrottle_offline_cfs_rqs(struct rq *rq) |
029632fb PZ |
3642 | { |
3643 | struct cfs_rq *cfs_rq; | |
3644 | ||
3645 | for_each_leaf_cfs_rq(rq, cfs_rq) { | |
3646 | struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg); | |
3647 | ||
3648 | if (!cfs_rq->runtime_enabled) | |
3649 | continue; | |
3650 | ||
3651 | /* | |
3652 | * clock_task is not advancing so we just need to make sure | |
3653 | * there's some valid quota amount | |
3654 | */ | |
3655 | cfs_rq->runtime_remaining = cfs_b->quota; | |
3656 | if (cfs_rq_throttled(cfs_rq)) | |
3657 | unthrottle_cfs_rq(cfs_rq); | |
3658 | } | |
3659 | } | |
3660 | ||
3661 | #else /* CONFIG_CFS_BANDWIDTH */ | |
f1b17280 PT |
3662 | static inline u64 cfs_rq_clock_task(struct cfs_rq *cfs_rq) |
3663 | { | |
78becc27 | 3664 | return rq_clock_task(rq_of(cfs_rq)); |
f1b17280 PT |
3665 | } |
3666 | ||
9dbdb155 | 3667 | static void account_cfs_rq_runtime(struct cfs_rq *cfs_rq, u64 delta_exec) {} |
d3d9dc33 PT |
3668 | static void check_cfs_rq_runtime(struct cfs_rq *cfs_rq) {} |
3669 | static void check_enqueue_throttle(struct cfs_rq *cfs_rq) {} | |
6c16a6dc | 3670 | static __always_inline void return_cfs_rq_runtime(struct cfs_rq *cfs_rq) {} |
85dac906 PT |
3671 | |
3672 | static inline int cfs_rq_throttled(struct cfs_rq *cfs_rq) | |
3673 | { | |
3674 | return 0; | |
3675 | } | |
64660c86 PT |
3676 | |
3677 | static inline int throttled_hierarchy(struct cfs_rq *cfs_rq) | |
3678 | { | |
3679 | return 0; | |
3680 | } | |
3681 | ||
3682 | static inline int throttled_lb_pair(struct task_group *tg, | |
3683 | int src_cpu, int dest_cpu) | |
3684 | { | |
3685 | return 0; | |
3686 | } | |
029632fb PZ |
3687 | |
3688 | void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b) {} | |
3689 | ||
3690 | #ifdef CONFIG_FAIR_GROUP_SCHED | |
3691 | static void init_cfs_rq_runtime(struct cfs_rq *cfs_rq) {} | |
ab84d31e PT |
3692 | #endif |
3693 | ||
029632fb PZ |
3694 | static inline struct cfs_bandwidth *tg_cfs_bandwidth(struct task_group *tg) |
3695 | { | |
3696 | return NULL; | |
3697 | } | |
3698 | static inline void destroy_cfs_bandwidth(struct cfs_bandwidth *cfs_b) {} | |
a4c96ae3 | 3699 | static inline void unthrottle_offline_cfs_rqs(struct rq *rq) {} |
029632fb PZ |
3700 | |
3701 | #endif /* CONFIG_CFS_BANDWIDTH */ | |
3702 | ||
bf0f6f24 IM |
3703 | /************************************************** |
3704 | * CFS operations on tasks: | |
3705 | */ | |
3706 | ||
8f4d37ec PZ |
3707 | #ifdef CONFIG_SCHED_HRTICK |
3708 | static void hrtick_start_fair(struct rq *rq, struct task_struct *p) | |
3709 | { | |
8f4d37ec PZ |
3710 | struct sched_entity *se = &p->se; |
3711 | struct cfs_rq *cfs_rq = cfs_rq_of(se); | |
3712 | ||
3713 | WARN_ON(task_rq(p) != rq); | |
3714 | ||
b39e66ea | 3715 | if (cfs_rq->nr_running > 1) { |
8f4d37ec PZ |
3716 | u64 slice = sched_slice(cfs_rq, se); |
3717 | u64 ran = se->sum_exec_runtime - se->prev_sum_exec_runtime; | |
3718 | s64 delta = slice - ran; | |
3719 | ||
3720 | if (delta < 0) { | |
3721 | if (rq->curr == p) | |
3722 | resched_task(p); | |
3723 | return; | |
3724 | } | |
3725 | ||
3726 | /* | |
3727 | * Don't schedule slices shorter than 10000ns, that just | |
3728 | * doesn't make sense. Rely on vruntime for fairness. | |
3729 | */ | |
31656519 | 3730 | if (rq->curr != p) |
157124c1 | 3731 | delta = max_t(s64, 10000LL, delta); |
8f4d37ec | 3732 | |
31656519 | 3733 | hrtick_start(rq, delta); |
8f4d37ec PZ |
3734 | } |
3735 | } | |
a4c2f00f PZ |
3736 | |
3737 | /* | |
3738 | * called from enqueue/dequeue and updates the hrtick when the | |
3739 | * current task is from our class and nr_running is low enough | |
3740 | * to matter. | |
3741 | */ | |
3742 | static void hrtick_update(struct rq *rq) | |
3743 | { | |
3744 | struct task_struct *curr = rq->curr; | |
3745 | ||
b39e66ea | 3746 | if (!hrtick_enabled(rq) || curr->sched_class != &fair_sched_class) |
a4c2f00f PZ |
3747 | return; |
3748 | ||
3749 | if (cfs_rq_of(&curr->se)->nr_running < sched_nr_latency) | |
3750 | hrtick_start_fair(rq, curr); | |
3751 | } | |
55e12e5e | 3752 | #else /* !CONFIG_SCHED_HRTICK */ |
8f4d37ec PZ |
3753 | static inline void |
3754 | hrtick_start_fair(struct rq *rq, struct task_struct *p) | |
3755 | { | |
3756 | } | |
a4c2f00f PZ |
3757 | |
3758 | static inline void hrtick_update(struct rq *rq) | |
3759 | { | |
3760 | } | |
8f4d37ec PZ |
3761 | #endif |
3762 | ||
bf0f6f24 IM |
3763 | /* |
3764 | * The enqueue_task method is called before nr_running is | |
3765 | * increased. Here we update the fair scheduling stats and | |
3766 | * then put the task into the rbtree: | |
3767 | */ | |
ea87bb78 | 3768 | static void |
371fd7e7 | 3769 | enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags) |
bf0f6f24 IM |
3770 | { |
3771 | struct cfs_rq *cfs_rq; | |
62fb1851 | 3772 | struct sched_entity *se = &p->se; |
bf0f6f24 IM |
3773 | |
3774 | for_each_sched_entity(se) { | |
62fb1851 | 3775 | if (se->on_rq) |
bf0f6f24 IM |
3776 | break; |
3777 | cfs_rq = cfs_rq_of(se); | |
88ec22d3 | 3778 | enqueue_entity(cfs_rq, se, flags); |
85dac906 PT |
3779 | |
3780 | /* | |
3781 | * end evaluation on encountering a throttled cfs_rq | |
3782 | * | |
3783 | * note: in the case of encountering a throttled cfs_rq we will | |
3784 | * post the final h_nr_running increment below. | |
3785 | */ | |
3786 | if (cfs_rq_throttled(cfs_rq)) | |
3787 | break; | |
953bfcd1 | 3788 | cfs_rq->h_nr_running++; |
85dac906 | 3789 | |
88ec22d3 | 3790 | flags = ENQUEUE_WAKEUP; |
bf0f6f24 | 3791 | } |
8f4d37ec | 3792 | |
2069dd75 | 3793 | for_each_sched_entity(se) { |
0f317143 | 3794 | cfs_rq = cfs_rq_of(se); |
953bfcd1 | 3795 | cfs_rq->h_nr_running++; |
2069dd75 | 3796 | |
85dac906 PT |
3797 | if (cfs_rq_throttled(cfs_rq)) |
3798 | break; | |
3799 | ||
17bc14b7 | 3800 | update_cfs_shares(cfs_rq); |
9ee474f5 | 3801 | update_entity_load_avg(se, 1); |
2069dd75 PZ |
3802 | } |
3803 | ||
18bf2805 BS |
3804 | if (!se) { |
3805 | update_rq_runnable_avg(rq, rq->nr_running); | |
85dac906 | 3806 | inc_nr_running(rq); |
18bf2805 | 3807 | } |
a4c2f00f | 3808 | hrtick_update(rq); |
bf0f6f24 IM |
3809 | } |
3810 | ||
2f36825b VP |
3811 | static void set_next_buddy(struct sched_entity *se); |
3812 | ||
bf0f6f24 IM |
3813 | /* |
3814 | * The dequeue_task method is called before nr_running is | |
3815 | * decreased. We remove the task from the rbtree and | |
3816 | * update the fair scheduling stats: | |
3817 | */ | |
371fd7e7 | 3818 | static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags) |
bf0f6f24 IM |
3819 | { |
3820 | struct cfs_rq *cfs_rq; | |
62fb1851 | 3821 | struct sched_entity *se = &p->se; |
2f36825b | 3822 | int task_sleep = flags & DEQUEUE_SLEEP; |
bf0f6f24 IM |
3823 | |
3824 | for_each_sched_entity(se) { | |
3825 | cfs_rq = cfs_rq_of(se); | |
371fd7e7 | 3826 | dequeue_entity(cfs_rq, se, flags); |
85dac906 PT |
3827 | |
3828 | /* | |
3829 | * end evaluation on encountering a throttled cfs_rq | |
3830 | * | |
3831 | * note: in the case of encountering a throttled cfs_rq we will | |
3832 | * post the final h_nr_running decrement below. | |
3833 | */ | |
3834 | if (cfs_rq_throttled(cfs_rq)) | |
3835 | break; | |
953bfcd1 | 3836 | cfs_rq->h_nr_running--; |
2069dd75 | 3837 | |
bf0f6f24 | 3838 | /* Don't dequeue parent if it has other entities besides us */ |
2f36825b VP |
3839 | if (cfs_rq->load.weight) { |
3840 | /* | |
3841 | * Bias pick_next to pick a task from this cfs_rq, as | |
3842 | * p is sleeping when it is within its sched_slice. | |
3843 | */ | |
3844 | if (task_sleep && parent_entity(se)) | |
3845 | set_next_buddy(parent_entity(se)); | |
9598c82d PT |
3846 | |
3847 | /* avoid re-evaluating load for this entity */ | |
3848 | se = parent_entity(se); | |
bf0f6f24 | 3849 | break; |
2f36825b | 3850 | } |
371fd7e7 | 3851 | flags |= DEQUEUE_SLEEP; |
bf0f6f24 | 3852 | } |
8f4d37ec | 3853 | |
2069dd75 | 3854 | for_each_sched_entity(se) { |
0f317143 | 3855 | cfs_rq = cfs_rq_of(se); |
953bfcd1 | 3856 | cfs_rq->h_nr_running--; |
2069dd75 | 3857 | |
85dac906 PT |
3858 | if (cfs_rq_throttled(cfs_rq)) |
3859 | break; | |
3860 | ||
17bc14b7 | 3861 | update_cfs_shares(cfs_rq); |
9ee474f5 | 3862 | update_entity_load_avg(se, 1); |
2069dd75 PZ |
3863 | } |
3864 | ||
18bf2805 | 3865 | if (!se) { |
85dac906 | 3866 | dec_nr_running(rq); |
18bf2805 BS |
3867 | update_rq_runnable_avg(rq, 1); |
3868 | } | |
a4c2f00f | 3869 | hrtick_update(rq); |
bf0f6f24 IM |
3870 | } |
3871 | ||
e7693a36 | 3872 | #ifdef CONFIG_SMP |
029632fb PZ |
3873 | /* Used instead of source_load when we know the type == 0 */ |
3874 | static unsigned long weighted_cpuload(const int cpu) | |
3875 | { | |
b92486cb | 3876 | return cpu_rq(cpu)->cfs.runnable_load_avg; |
029632fb PZ |
3877 | } |
3878 | ||
3879 | /* | |
3880 | * Return a low guess at the load of a migration-source cpu weighted | |
3881 | * according to the scheduling class and "nice" value. | |
3882 | * | |
3883 | * We want to under-estimate the load of migration sources, to | |
3884 | * balance conservatively. | |
3885 | */ | |
3886 | static unsigned long source_load(int cpu, int type) | |
3887 | { | |
3888 | struct rq *rq = cpu_rq(cpu); | |
3889 | unsigned long total = weighted_cpuload(cpu); | |
3890 | ||
3891 | if (type == 0 || !sched_feat(LB_BIAS)) | |
3892 | return total; | |
3893 | ||
3894 | return min(rq->cpu_load[type-1], total); | |
3895 | } | |
3896 | ||
3897 | /* | |
3898 | * Return a high guess at the load of a migration-target cpu weighted | |
3899 | * according to the scheduling class and "nice" value. | |
3900 | */ | |
3901 | static unsigned long target_load(int cpu, int type) | |
3902 | { | |
3903 | struct rq *rq = cpu_rq(cpu); | |
3904 | unsigned long total = weighted_cpuload(cpu); | |
3905 | ||
3906 | if (type == 0 || !sched_feat(LB_BIAS)) | |
3907 | return total; | |
3908 | ||
3909 | return max(rq->cpu_load[type-1], total); | |
3910 | } | |
3911 | ||
3912 | static unsigned long power_of(int cpu) | |
3913 | { | |
3914 | return cpu_rq(cpu)->cpu_power; | |
3915 | } | |
3916 | ||
3917 | static unsigned long cpu_avg_load_per_task(int cpu) | |
3918 | { | |
3919 | struct rq *rq = cpu_rq(cpu); | |
3920 | unsigned long nr_running = ACCESS_ONCE(rq->nr_running); | |
b92486cb | 3921 | unsigned long load_avg = rq->cfs.runnable_load_avg; |
029632fb PZ |
3922 | |
3923 | if (nr_running) | |
b92486cb | 3924 | return load_avg / nr_running; |
029632fb PZ |
3925 | |
3926 | return 0; | |
3927 | } | |
3928 | ||
62470419 MW |
3929 | static void record_wakee(struct task_struct *p) |
3930 | { | |
3931 | /* | |
3932 | * Rough decay (wiping) for cost saving, don't worry | |
3933 | * about the boundary, really active task won't care | |
3934 | * about the loss. | |
3935 | */ | |
3936 | if (jiffies > current->wakee_flip_decay_ts + HZ) { | |
3937 | current->wakee_flips = 0; | |
3938 | current->wakee_flip_decay_ts = jiffies; | |
3939 | } | |
3940 | ||
3941 | if (current->last_wakee != p) { | |
3942 | current->last_wakee = p; | |
3943 | current->wakee_flips++; | |
3944 | } | |
3945 | } | |
098fb9db | 3946 | |
74f8e4b2 | 3947 | static void task_waking_fair(struct task_struct *p) |
88ec22d3 PZ |
3948 | { |
3949 | struct sched_entity *se = &p->se; | |
3950 | struct cfs_rq *cfs_rq = cfs_rq_of(se); | |
3fe1698b PZ |
3951 | u64 min_vruntime; |
3952 | ||
3953 | #ifndef CONFIG_64BIT | |
3954 | u64 min_vruntime_copy; | |
88ec22d3 | 3955 | |
3fe1698b PZ |
3956 | do { |
3957 | min_vruntime_copy = cfs_rq->min_vruntime_copy; | |
3958 | smp_rmb(); | |
3959 | min_vruntime = cfs_rq->min_vruntime; | |
3960 | } while (min_vruntime != min_vruntime_copy); | |
3961 | #else | |
3962 | min_vruntime = cfs_rq->min_vruntime; | |
3963 | #endif | |
88ec22d3 | 3964 | |
3fe1698b | 3965 | se->vruntime -= min_vruntime; |
62470419 | 3966 | record_wakee(p); |
88ec22d3 PZ |
3967 | } |
3968 | ||
bb3469ac | 3969 | #ifdef CONFIG_FAIR_GROUP_SCHED |
f5bfb7d9 PZ |
3970 | /* |
3971 | * effective_load() calculates the load change as seen from the root_task_group | |
3972 | * | |
3973 | * Adding load to a group doesn't make a group heavier, but can cause movement | |
3974 | * of group shares between cpus. Assuming the shares were perfectly aligned one | |
3975 | * can calculate the shift in shares. | |
cf5f0acf PZ |
3976 | * |
3977 | * Calculate the effective load difference if @wl is added (subtracted) to @tg | |
3978 | * on this @cpu and results in a total addition (subtraction) of @wg to the | |
3979 | * total group weight. | |
3980 | * | |
3981 | * Given a runqueue weight distribution (rw_i) we can compute a shares | |
3982 | * distribution (s_i) using: | |
3983 | * | |
3984 | * s_i = rw_i / \Sum rw_j (1) | |
3985 | * | |
3986 | * Suppose we have 4 CPUs and our @tg is a direct child of the root group and | |
3987 | * has 7 equal weight tasks, distributed as below (rw_i), with the resulting | |
3988 | * shares distribution (s_i): | |
3989 | * | |
3990 | * rw_i = { 2, 4, 1, 0 } | |
3991 | * s_i = { 2/7, 4/7, 1/7, 0 } | |
3992 | * | |
3993 | * As per wake_affine() we're interested in the load of two CPUs (the CPU the | |
3994 | * task used to run on and the CPU the waker is running on), we need to | |
3995 | * compute the effect of waking a task on either CPU and, in case of a sync | |
3996 | * wakeup, compute the effect of the current task going to sleep. | |
3997 | * | |
3998 | * So for a change of @wl to the local @cpu with an overall group weight change | |
3999 | * of @wl we can compute the new shares distribution (s'_i) using: | |
4000 | * | |
4001 | * s'_i = (rw_i + @wl) / (@wg + \Sum rw_j) (2) | |
4002 | * | |
4003 | * Suppose we're interested in CPUs 0 and 1, and want to compute the load | |
4004 | * differences in waking a task to CPU 0. The additional task changes the | |
4005 | * weight and shares distributions like: | |
4006 | * | |
4007 | * rw'_i = { 3, 4, 1, 0 } | |
4008 | * s'_i = { 3/8, 4/8, 1/8, 0 } | |
4009 | * | |
4010 | * We can then compute the difference in effective weight by using: | |
4011 | * | |
4012 | * dw_i = S * (s'_i - s_i) (3) | |
4013 | * | |
4014 | * Where 'S' is the group weight as seen by its parent. | |
4015 | * | |
4016 | * Therefore the effective change in loads on CPU 0 would be 5/56 (3/8 - 2/7) | |
4017 | * times the weight of the group. The effect on CPU 1 would be -4/56 (4/8 - | |
4018 | * 4/7) times the weight of the group. | |
f5bfb7d9 | 4019 | */ |
2069dd75 | 4020 | static long effective_load(struct task_group *tg, int cpu, long wl, long wg) |
bb3469ac | 4021 | { |
4be9daaa | 4022 | struct sched_entity *se = tg->se[cpu]; |
f1d239f7 | 4023 | |
9722c2da | 4024 | if (!tg->parent) /* the trivial, non-cgroup case */ |
f1d239f7 PZ |
4025 | return wl; |
4026 | ||
4be9daaa | 4027 | for_each_sched_entity(se) { |
cf5f0acf | 4028 | long w, W; |
4be9daaa | 4029 | |
977dda7c | 4030 | tg = se->my_q->tg; |
bb3469ac | 4031 | |
cf5f0acf PZ |
4032 | /* |
4033 | * W = @wg + \Sum rw_j | |
4034 | */ | |
4035 | W = wg + calc_tg_weight(tg, se->my_q); | |
4be9daaa | 4036 | |
cf5f0acf PZ |
4037 | /* |
4038 | * w = rw_i + @wl | |
4039 | */ | |
4040 | w = se->my_q->load.weight + wl; | |
940959e9 | 4041 | |
cf5f0acf PZ |
4042 | /* |
4043 | * wl = S * s'_i; see (2) | |
4044 | */ | |
4045 | if (W > 0 && w < W) | |
4046 | wl = (w * tg->shares) / W; | |
977dda7c PT |
4047 | else |
4048 | wl = tg->shares; | |
940959e9 | 4049 | |
cf5f0acf PZ |
4050 | /* |
4051 | * Per the above, wl is the new se->load.weight value; since | |
4052 | * those are clipped to [MIN_SHARES, ...) do so now. See | |
4053 | * calc_cfs_shares(). | |
4054 | */ | |
977dda7c PT |
4055 | if (wl < MIN_SHARES) |
4056 | wl = MIN_SHARES; | |
cf5f0acf PZ |
4057 | |
4058 | /* | |
4059 | * wl = dw_i = S * (s'_i - s_i); see (3) | |
4060 | */ | |
977dda7c | 4061 | wl -= se->load.weight; |
cf5f0acf PZ |
4062 | |
4063 | /* | |
4064 | * Recursively apply this logic to all parent groups to compute | |
4065 | * the final effective load change on the root group. Since | |
4066 | * only the @tg group gets extra weight, all parent groups can | |
4067 | * only redistribute existing shares. @wl is the shift in shares | |
4068 | * resulting from this level per the above. | |
4069 | */ | |
4be9daaa | 4070 | wg = 0; |
4be9daaa | 4071 | } |
bb3469ac | 4072 | |
4be9daaa | 4073 | return wl; |
bb3469ac PZ |
4074 | } |
4075 | #else | |
4be9daaa | 4076 | |
58d081b5 | 4077 | static long effective_load(struct task_group *tg, int cpu, long wl, long wg) |
4be9daaa | 4078 | { |
83378269 | 4079 | return wl; |
bb3469ac | 4080 | } |
4be9daaa | 4081 | |
bb3469ac PZ |
4082 | #endif |
4083 | ||
62470419 MW |
4084 | static int wake_wide(struct task_struct *p) |
4085 | { | |
7d9ffa89 | 4086 | int factor = this_cpu_read(sd_llc_size); |
62470419 MW |
4087 | |
4088 | /* | |
4089 | * Yeah, it's the switching-frequency, could means many wakee or | |
4090 | * rapidly switch, use factor here will just help to automatically | |
4091 | * adjust the loose-degree, so bigger node will lead to more pull. | |
4092 | */ | |
4093 | if (p->wakee_flips > factor) { | |
4094 | /* | |
4095 | * wakee is somewhat hot, it needs certain amount of cpu | |
4096 | * resource, so if waker is far more hot, prefer to leave | |
4097 | * it alone. | |
4098 | */ | |
4099 | if (current->wakee_flips > (factor * p->wakee_flips)) | |
4100 | return 1; | |
4101 | } | |
4102 | ||
4103 | return 0; | |
4104 | } | |
4105 | ||
c88d5910 | 4106 | static int wake_affine(struct sched_domain *sd, struct task_struct *p, int sync) |
098fb9db | 4107 | { |
e37b6a7b | 4108 | s64 this_load, load; |
c88d5910 | 4109 | int idx, this_cpu, prev_cpu; |
098fb9db | 4110 | unsigned long tl_per_task; |
c88d5910 | 4111 | struct task_group *tg; |
83378269 | 4112 | unsigned long weight; |
b3137bc8 | 4113 | int balanced; |
098fb9db | 4114 | |
62470419 MW |
4115 | /* |
4116 | * If we wake multiple tasks be careful to not bounce | |
4117 | * ourselves around too much. | |
4118 | */ | |
4119 | if (wake_wide(p)) | |
4120 | return 0; | |
4121 | ||
c88d5910 PZ |
4122 | idx = sd->wake_idx; |
4123 | this_cpu = smp_processor_id(); | |
4124 | prev_cpu = task_cpu(p); | |
4125 | load = source_load(prev_cpu, idx); | |
4126 | this_load = target_load(this_cpu, idx); | |
098fb9db | 4127 | |
b3137bc8 MG |
4128 | /* |
4129 | * If sync wakeup then subtract the (maximum possible) | |
4130 | * effect of the currently running task from the load | |
4131 | * of the current CPU: | |
4132 | */ | |
83378269 PZ |
4133 | if (sync) { |
4134 | tg = task_group(current); | |
4135 | weight = current->se.load.weight; | |
4136 | ||
c88d5910 | 4137 | this_load += effective_load(tg, this_cpu, -weight, -weight); |
83378269 PZ |
4138 | load += effective_load(tg, prev_cpu, 0, -weight); |
4139 | } | |
b3137bc8 | 4140 | |
83378269 PZ |
4141 | tg = task_group(p); |
4142 | weight = p->se.load.weight; | |
b3137bc8 | 4143 | |
71a29aa7 PZ |
4144 | /* |
4145 | * In low-load situations, where prev_cpu is idle and this_cpu is idle | |
c88d5910 PZ |
4146 | * due to the sync cause above having dropped this_load to 0, we'll |
4147 | * always have an imbalance, but there's really nothing you can do | |
4148 | * about that, so that's good too. | |
71a29aa7 PZ |
4149 | * |
4150 | * Otherwise check if either cpus are near enough in load to allow this | |
4151 | * task to be woken on this_cpu. | |
4152 | */ | |
e37b6a7b PT |
4153 | if (this_load > 0) { |
4154 | s64 this_eff_load, prev_eff_load; | |
e51fd5e2 PZ |
4155 | |
4156 | this_eff_load = 100; | |
4157 | this_eff_load *= power_of(prev_cpu); | |
4158 | this_eff_load *= this_load + | |
4159 | effective_load(tg, this_cpu, weight, weight); | |
4160 | ||
4161 | prev_eff_load = 100 + (sd->imbalance_pct - 100) / 2; | |
4162 | prev_eff_load *= power_of(this_cpu); | |
4163 | prev_eff_load *= load + effective_load(tg, prev_cpu, 0, weight); | |
4164 | ||
4165 | balanced = this_eff_load <= prev_eff_load; | |
4166 | } else | |
4167 | balanced = true; | |
b3137bc8 | 4168 | |
098fb9db | 4169 | /* |
4ae7d5ce IM |
4170 | * If the currently running task will sleep within |
4171 | * a reasonable amount of time then attract this newly | |
4172 | * woken task: | |
098fb9db | 4173 | */ |
2fb7635c PZ |
4174 | if (sync && balanced) |
4175 | return 1; | |
098fb9db | 4176 | |
41acab88 | 4177 | schedstat_inc(p, se.statistics.nr_wakeups_affine_attempts); |
098fb9db IM |
4178 | tl_per_task = cpu_avg_load_per_task(this_cpu); |
4179 | ||
c88d5910 PZ |
4180 | if (balanced || |
4181 | (this_load <= load && | |
4182 | this_load + target_load(prev_cpu, idx) <= tl_per_task)) { | |
098fb9db IM |
4183 | /* |
4184 | * This domain has SD_WAKE_AFFINE and | |
4185 | * p is cache cold in this domain, and | |
4186 | * there is no bad imbalance. | |
4187 | */ | |
c88d5910 | 4188 | schedstat_inc(sd, ttwu_move_affine); |
41acab88 | 4189 | schedstat_inc(p, se.statistics.nr_wakeups_affine); |
098fb9db IM |
4190 | |
4191 | return 1; | |
4192 | } | |
4193 | return 0; | |
4194 | } | |
4195 | ||
aaee1203 PZ |
4196 | /* |
4197 | * find_idlest_group finds and returns the least busy CPU group within the | |
4198 | * domain. | |
4199 | */ | |
4200 | static struct sched_group * | |
78e7ed53 | 4201 | find_idlest_group(struct sched_domain *sd, struct task_struct *p, |
c44f2a02 | 4202 | int this_cpu, int sd_flag) |
e7693a36 | 4203 | { |
b3bd3de6 | 4204 | struct sched_group *idlest = NULL, *group = sd->groups; |
aaee1203 | 4205 | unsigned long min_load = ULONG_MAX, this_load = 0; |
c44f2a02 | 4206 | int load_idx = sd->forkexec_idx; |
aaee1203 | 4207 | int imbalance = 100 + (sd->imbalance_pct-100)/2; |
e7693a36 | 4208 | |
c44f2a02 VG |
4209 | if (sd_flag & SD_BALANCE_WAKE) |
4210 | load_idx = sd->wake_idx; | |
4211 | ||
aaee1203 PZ |
4212 | do { |
4213 | unsigned long load, avg_load; | |
4214 | int local_group; | |
4215 | int i; | |
e7693a36 | 4216 | |
aaee1203 PZ |
4217 | /* Skip over this group if it has no CPUs allowed */ |
4218 | if (!cpumask_intersects(sched_group_cpus(group), | |
fa17b507 | 4219 | tsk_cpus_allowed(p))) |
aaee1203 PZ |
4220 | continue; |
4221 | ||
4222 | local_group = cpumask_test_cpu(this_cpu, | |
4223 | sched_group_cpus(group)); | |
4224 | ||
4225 | /* Tally up the load of all CPUs in the group */ | |
4226 | avg_load = 0; | |
4227 | ||
4228 | for_each_cpu(i, sched_group_cpus(group)) { | |
4229 | /* Bias balancing toward cpus of our domain */ | |
4230 | if (local_group) | |
4231 | load = source_load(i, load_idx); | |
4232 | else | |
4233 | load = target_load(i, load_idx); | |
4234 | ||
4235 | avg_load += load; | |
4236 | } | |
4237 | ||
4238 | /* Adjust by relative CPU power of the group */ | |
9c3f75cb | 4239 | avg_load = (avg_load * SCHED_POWER_SCALE) / group->sgp->power; |
aaee1203 PZ |
4240 | |
4241 | if (local_group) { | |
4242 | this_load = avg_load; | |
aaee1203 PZ |
4243 | } else if (avg_load < min_load) { |
4244 | min_load = avg_load; | |
4245 | idlest = group; | |
4246 | } | |
4247 | } while (group = group->next, group != sd->groups); | |
4248 | ||
4249 | if (!idlest || 100*this_load < imbalance*min_load) | |
4250 | return NULL; | |
4251 | return idlest; | |
4252 | } | |
4253 | ||
4254 | /* | |
4255 | * find_idlest_cpu - find the idlest cpu among the cpus in group. | |
4256 | */ | |
4257 | static int | |
4258 | find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu) | |
4259 | { | |
4260 | unsigned long load, min_load = ULONG_MAX; | |
4261 | int idlest = -1; | |
4262 | int i; | |
4263 | ||
4264 | /* Traverse only the allowed CPUs */ | |
fa17b507 | 4265 | for_each_cpu_and(i, sched_group_cpus(group), tsk_cpus_allowed(p)) { |
aaee1203 PZ |
4266 | load = weighted_cpuload(i); |
4267 | ||
4268 | if (load < min_load || (load == min_load && i == this_cpu)) { | |
4269 | min_load = load; | |
4270 | idlest = i; | |
e7693a36 GH |
4271 | } |
4272 | } | |
4273 | ||
aaee1203 PZ |
4274 | return idlest; |
4275 | } | |
e7693a36 | 4276 | |
a50bde51 PZ |
4277 | /* |
4278 | * Try and locate an idle CPU in the sched_domain. | |
4279 | */ | |
99bd5e2f | 4280 | static int select_idle_sibling(struct task_struct *p, int target) |
a50bde51 | 4281 | { |
99bd5e2f | 4282 | struct sched_domain *sd; |
37407ea7 | 4283 | struct sched_group *sg; |
e0a79f52 | 4284 | int i = task_cpu(p); |
a50bde51 | 4285 | |
e0a79f52 MG |
4286 | if (idle_cpu(target)) |
4287 | return target; | |
99bd5e2f SS |
4288 | |
4289 | /* | |
e0a79f52 | 4290 | * If the prevous cpu is cache affine and idle, don't be stupid. |
99bd5e2f | 4291 | */ |
e0a79f52 MG |
4292 | if (i != target && cpus_share_cache(i, target) && idle_cpu(i)) |
4293 | return i; | |
a50bde51 PZ |
4294 | |
4295 | /* | |
37407ea7 | 4296 | * Otherwise, iterate the domains and find an elegible idle cpu. |
a50bde51 | 4297 | */ |
518cd623 | 4298 | sd = rcu_dereference(per_cpu(sd_llc, target)); |
970e1789 | 4299 | for_each_lower_domain(sd) { |
37407ea7 LT |
4300 | sg = sd->groups; |
4301 | do { | |
4302 | if (!cpumask_intersects(sched_group_cpus(sg), | |
4303 | tsk_cpus_allowed(p))) | |
4304 | goto next; | |
4305 | ||
4306 | for_each_cpu(i, sched_group_cpus(sg)) { | |
e0a79f52 | 4307 | if (i == target || !idle_cpu(i)) |
37407ea7 LT |
4308 | goto next; |
4309 | } | |
970e1789 | 4310 | |
37407ea7 LT |
4311 | target = cpumask_first_and(sched_group_cpus(sg), |
4312 | tsk_cpus_allowed(p)); | |
4313 | goto done; | |
4314 | next: | |
4315 | sg = sg->next; | |
4316 | } while (sg != sd->groups); | |
4317 | } | |
4318 | done: | |
a50bde51 PZ |
4319 | return target; |
4320 | } | |
4321 | ||
aaee1203 PZ |
4322 | /* |
4323 | * sched_balance_self: balance the current task (running on cpu) in domains | |
4324 | * that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and | |
4325 | * SD_BALANCE_EXEC. | |
4326 | * | |
4327 | * Balance, ie. select the least loaded group. | |
4328 | * | |
4329 | * Returns the target CPU number, or the same CPU if no balancing is needed. | |
4330 | * | |
4331 | * preempt must be disabled. | |
4332 | */ | |
0017d735 | 4333 | static int |
ac66f547 | 4334 | select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_flags) |
aaee1203 | 4335 | { |
29cd8bae | 4336 | struct sched_domain *tmp, *affine_sd = NULL, *sd = NULL; |
c88d5910 | 4337 | int cpu = smp_processor_id(); |
c88d5910 | 4338 | int new_cpu = cpu; |
99bd5e2f | 4339 | int want_affine = 0; |
5158f4e4 | 4340 | int sync = wake_flags & WF_SYNC; |
c88d5910 | 4341 | |
29baa747 | 4342 | if (p->nr_cpus_allowed == 1) |
76854c7e MG |
4343 | return prev_cpu; |
4344 | ||
0763a660 | 4345 | if (sd_flag & SD_BALANCE_WAKE) { |
fa17b507 | 4346 | if (cpumask_test_cpu(cpu, tsk_cpus_allowed(p))) |
c88d5910 PZ |
4347 | want_affine = 1; |
4348 | new_cpu = prev_cpu; | |
4349 | } | |
aaee1203 | 4350 | |
dce840a0 | 4351 | rcu_read_lock(); |
aaee1203 | 4352 | for_each_domain(cpu, tmp) { |
e4f42888 PZ |
4353 | if (!(tmp->flags & SD_LOAD_BALANCE)) |
4354 | continue; | |
4355 | ||
fe3bcfe1 | 4356 | /* |
99bd5e2f SS |
4357 | * If both cpu and prev_cpu are part of this domain, |
4358 | * cpu is a valid SD_WAKE_AFFINE target. | |
fe3bcfe1 | 4359 | */ |
99bd5e2f SS |
4360 | if (want_affine && (tmp->flags & SD_WAKE_AFFINE) && |
4361 | cpumask_test_cpu(prev_cpu, sched_domain_span(tmp))) { | |
4362 | affine_sd = tmp; | |
29cd8bae | 4363 | break; |
f03542a7 | 4364 | } |
29cd8bae | 4365 | |
f03542a7 | 4366 | if (tmp->flags & sd_flag) |
29cd8bae PZ |
4367 | sd = tmp; |
4368 | } | |
4369 | ||
8b911acd | 4370 | if (affine_sd) { |
f03542a7 | 4371 | if (cpu != prev_cpu && wake_affine(affine_sd, p, sync)) |
dce840a0 PZ |
4372 | prev_cpu = cpu; |
4373 | ||
4374 | new_cpu = select_idle_sibling(p, prev_cpu); | |
4375 | goto unlock; | |
8b911acd | 4376 | } |
e7693a36 | 4377 | |
aaee1203 PZ |
4378 | while (sd) { |
4379 | struct sched_group *group; | |
c88d5910 | 4380 | int weight; |
098fb9db | 4381 | |
0763a660 | 4382 | if (!(sd->flags & sd_flag)) { |
aaee1203 PZ |
4383 | sd = sd->child; |
4384 | continue; | |
4385 | } | |
098fb9db | 4386 | |
c44f2a02 | 4387 | group = find_idlest_group(sd, p, cpu, sd_flag); |
aaee1203 PZ |
4388 | if (!group) { |
4389 | sd = sd->child; | |
4390 | continue; | |
4391 | } | |
4ae7d5ce | 4392 | |
d7c33c49 | 4393 | new_cpu = find_idlest_cpu(group, p, cpu); |
aaee1203 PZ |
4394 | if (new_cpu == -1 || new_cpu == cpu) { |
4395 | /* Now try balancing at a lower domain level of cpu */ | |
4396 | sd = sd->child; | |
4397 | continue; | |
e7693a36 | 4398 | } |
aaee1203 PZ |
4399 | |
4400 | /* Now try balancing at a lower domain level of new_cpu */ | |
4401 | cpu = new_cpu; | |
669c55e9 | 4402 | weight = sd->span_weight; |
aaee1203 PZ |
4403 | sd = NULL; |
4404 | for_each_domain(cpu, tmp) { | |
669c55e9 | 4405 | if (weight <= tmp->span_weight) |
aaee1203 | 4406 | break; |
0763a660 | 4407 | if (tmp->flags & sd_flag) |
aaee1203 PZ |
4408 | sd = tmp; |
4409 | } | |
4410 | /* while loop will break here if sd == NULL */ | |
e7693a36 | 4411 | } |
dce840a0 PZ |
4412 | unlock: |
4413 | rcu_read_unlock(); | |
e7693a36 | 4414 | |
c88d5910 | 4415 | return new_cpu; |
e7693a36 | 4416 | } |
0a74bef8 PT |
4417 | |
4418 | /* | |
4419 | * Called immediately before a task is migrated to a new cpu; task_cpu(p) and | |
4420 | * cfs_rq_of(p) references at time of call are still valid and identify the | |
4421 | * previous cpu. However, the caller only guarantees p->pi_lock is held; no | |
4422 | * other assumptions, including the state of rq->lock, should be made. | |
4423 | */ | |
4424 | static void | |
4425 | migrate_task_rq_fair(struct task_struct *p, int next_cpu) | |
4426 | { | |
aff3e498 PT |
4427 | struct sched_entity *se = &p->se; |
4428 | struct cfs_rq *cfs_rq = cfs_rq_of(se); | |
4429 | ||
4430 | /* | |
4431 | * Load tracking: accumulate removed load so that it can be processed | |
4432 | * when we next update owning cfs_rq under rq->lock. Tasks contribute | |
4433 | * to blocked load iff they have a positive decay-count. It can never | |
4434 | * be negative here since on-rq tasks have decay-count == 0. | |
4435 | */ | |
4436 | if (se->avg.decay_count) { | |
4437 | se->avg.decay_count = -__synchronize_entity_decay(se); | |
2509940f AS |
4438 | atomic_long_add(se->avg.load_avg_contrib, |
4439 | &cfs_rq->removed_load); | |
aff3e498 | 4440 | } |
0a74bef8 | 4441 | } |
e7693a36 GH |
4442 | #endif /* CONFIG_SMP */ |
4443 | ||
e52fb7c0 PZ |
4444 | static unsigned long |
4445 | wakeup_gran(struct sched_entity *curr, struct sched_entity *se) | |
0bbd3336 PZ |
4446 | { |
4447 | unsigned long gran = sysctl_sched_wakeup_granularity; | |
4448 | ||
4449 | /* | |
e52fb7c0 PZ |
4450 | * Since its curr running now, convert the gran from real-time |
4451 | * to virtual-time in his units. | |
13814d42 MG |
4452 | * |
4453 | * By using 'se' instead of 'curr' we penalize light tasks, so | |
4454 | * they get preempted easier. That is, if 'se' < 'curr' then | |
4455 | * the resulting gran will be larger, therefore penalizing the | |
4456 | * lighter, if otoh 'se' > 'curr' then the resulting gran will | |
4457 | * be smaller, again penalizing the lighter task. | |
4458 | * | |
4459 | * This is especially important for buddies when the leftmost | |
4460 | * task is higher priority than the buddy. | |
0bbd3336 | 4461 | */ |
f4ad9bd2 | 4462 | return calc_delta_fair(gran, se); |
0bbd3336 PZ |
4463 | } |
4464 | ||
464b7527 PZ |
4465 | /* |
4466 | * Should 'se' preempt 'curr'. | |
4467 | * | |
4468 | * |s1 | |
4469 | * |s2 | |
4470 | * |s3 | |
4471 | * g | |
4472 | * |<--->|c | |
4473 | * | |
4474 | * w(c, s1) = -1 | |
4475 | * w(c, s2) = 0 | |
4476 | * w(c, s3) = 1 | |
4477 | * | |
4478 | */ | |
4479 | static int | |
4480 | wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se) | |
4481 | { | |
4482 | s64 gran, vdiff = curr->vruntime - se->vruntime; | |
4483 | ||
4484 | if (vdiff <= 0) | |
4485 | return -1; | |
4486 | ||
e52fb7c0 | 4487 | gran = wakeup_gran(curr, se); |
464b7527 PZ |
4488 | if (vdiff > gran) |
4489 | return 1; | |
4490 | ||
4491 | return 0; | |
4492 | } | |
4493 | ||
02479099 PZ |
4494 | static void set_last_buddy(struct sched_entity *se) |
4495 | { | |
69c80f3e VP |
4496 | if (entity_is_task(se) && unlikely(task_of(se)->policy == SCHED_IDLE)) |
4497 | return; | |
4498 | ||
4499 | for_each_sched_entity(se) | |
4500 | cfs_rq_of(se)->last = se; | |
02479099 PZ |
4501 | } |
4502 | ||
4503 | static void set_next_buddy(struct sched_entity *se) | |
4504 | { | |
69c80f3e VP |
4505 | if (entity_is_task(se) && unlikely(task_of(se)->policy == SCHED_IDLE)) |
4506 | return; | |
4507 | ||
4508 | for_each_sched_entity(se) | |
4509 | cfs_rq_of(se)->next = se; | |
02479099 PZ |
4510 | } |
4511 | ||
ac53db59 RR |
4512 | static void set_skip_buddy(struct sched_entity *se) |
4513 | { | |
69c80f3e VP |
4514 | for_each_sched_entity(se) |
4515 | cfs_rq_of(se)->skip = se; | |
ac53db59 RR |
4516 | } |
4517 | ||
bf0f6f24 IM |
4518 | /* |
4519 | * Preempt the current task with a newly woken task if needed: | |
4520 | */ | |
5a9b86f6 | 4521 | static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_flags) |
bf0f6f24 IM |
4522 | { |
4523 | struct task_struct *curr = rq->curr; | |
8651a86c | 4524 | struct sched_entity *se = &curr->se, *pse = &p->se; |
03e89e45 | 4525 | struct cfs_rq *cfs_rq = task_cfs_rq(curr); |
f685ceac | 4526 | int scale = cfs_rq->nr_running >= sched_nr_latency; |
2f36825b | 4527 | int next_buddy_marked = 0; |
bf0f6f24 | 4528 | |
4ae7d5ce IM |
4529 | if (unlikely(se == pse)) |
4530 | return; | |
4531 | ||
5238cdd3 | 4532 | /* |
ddcdf6e7 | 4533 | * This is possible from callers such as move_task(), in which we |
5238cdd3 PT |
4534 | * unconditionally check_prempt_curr() after an enqueue (which may have |
4535 | * lead to a throttle). This both saves work and prevents false | |
4536 | * next-buddy nomination below. | |
4537 | */ | |
4538 | if (unlikely(throttled_hierarchy(cfs_rq_of(pse)))) | |
4539 | return; | |
4540 | ||
2f36825b | 4541 | if (sched_feat(NEXT_BUDDY) && scale && !(wake_flags & WF_FORK)) { |
3cb63d52 | 4542 | set_next_buddy(pse); |
2f36825b VP |
4543 | next_buddy_marked = 1; |
4544 | } | |
57fdc26d | 4545 | |
aec0a514 BR |
4546 | /* |
4547 | * We can come here with TIF_NEED_RESCHED already set from new task | |
4548 | * wake up path. | |
5238cdd3 PT |
4549 | * |
4550 | * Note: this also catches the edge-case of curr being in a throttled | |
4551 | * group (e.g. via set_curr_task), since update_curr() (in the | |
4552 | * enqueue of curr) will have resulted in resched being set. This | |
4553 | * prevents us from potentially nominating it as a false LAST_BUDDY | |
4554 | * below. | |
aec0a514 BR |
4555 | */ |
4556 | if (test_tsk_need_resched(curr)) | |
4557 | return; | |
4558 | ||
a2f5c9ab DH |
4559 | /* Idle tasks are by definition preempted by non-idle tasks. */ |
4560 | if (unlikely(curr->policy == SCHED_IDLE) && | |
4561 | likely(p->policy != SCHED_IDLE)) | |
4562 | goto preempt; | |
4563 | ||
91c234b4 | 4564 | /* |
a2f5c9ab DH |
4565 | * Batch and idle tasks do not preempt non-idle tasks (their preemption |
4566 | * is driven by the tick): | |
91c234b4 | 4567 | */ |
8ed92e51 | 4568 | if (unlikely(p->policy != SCHED_NORMAL) || !sched_feat(WAKEUP_PREEMPTION)) |
91c234b4 | 4569 | return; |
bf0f6f24 | 4570 | |
464b7527 | 4571 | find_matching_se(&se, &pse); |
9bbd7374 | 4572 | update_curr(cfs_rq_of(se)); |
002f128b | 4573 | BUG_ON(!pse); |
2f36825b VP |
4574 | if (wakeup_preempt_entity(se, pse) == 1) { |
4575 | /* | |
4576 | * Bias pick_next to pick the sched entity that is | |
4577 | * triggering this preemption. | |
4578 | */ | |
4579 | if (!next_buddy_marked) | |
4580 | set_next_buddy(pse); | |
3a7e73a2 | 4581 | goto preempt; |
2f36825b | 4582 | } |
464b7527 | 4583 | |
3a7e73a2 | 4584 | return; |
a65ac745 | 4585 | |
3a7e73a2 PZ |
4586 | preempt: |
4587 | resched_task(curr); | |
4588 | /* | |
4589 | * Only set the backward buddy when the current task is still | |
4590 | * on the rq. This can happen when a wakeup gets interleaved | |
4591 | * with schedule on the ->pre_schedule() or idle_balance() | |
4592 | * point, either of which can * drop the rq lock. | |
4593 | * | |
4594 | * Also, during early boot the idle thread is in the fair class, | |
4595 | * for obvious reasons its a bad idea to schedule back to it. | |
4596 | */ | |
4597 | if (unlikely(!se->on_rq || curr == rq->idle)) | |
4598 | return; | |
4599 | ||
4600 | if (sched_feat(LAST_BUDDY) && scale && entity_is_task(se)) | |
4601 | set_last_buddy(se); | |
bf0f6f24 IM |
4602 | } |
4603 | ||
fb8d4724 | 4604 | static struct task_struct *pick_next_task_fair(struct rq *rq) |
bf0f6f24 | 4605 | { |
8f4d37ec | 4606 | struct task_struct *p; |
bf0f6f24 IM |
4607 | struct cfs_rq *cfs_rq = &rq->cfs; |
4608 | struct sched_entity *se; | |
4609 | ||
36ace27e | 4610 | if (!cfs_rq->nr_running) |
bf0f6f24 IM |
4611 | return NULL; |
4612 | ||
4613 | do { | |
9948f4b2 | 4614 | se = pick_next_entity(cfs_rq); |
f4b6755f | 4615 | set_next_entity(cfs_rq, se); |
bf0f6f24 IM |
4616 | cfs_rq = group_cfs_rq(se); |
4617 | } while (cfs_rq); | |
4618 | ||
8f4d37ec | 4619 | p = task_of(se); |
b39e66ea MG |
4620 | if (hrtick_enabled(rq)) |
4621 | hrtick_start_fair(rq, p); | |
8f4d37ec PZ |
4622 | |
4623 | return p; | |
bf0f6f24 IM |
4624 | } |
4625 | ||
4626 | /* | |
4627 | * Account for a descheduled task: | |
4628 | */ | |
31ee529c | 4629 | static void put_prev_task_fair(struct rq *rq, struct task_struct *prev) |
bf0f6f24 IM |
4630 | { |
4631 | struct sched_entity *se = &prev->se; | |
4632 | struct cfs_rq *cfs_rq; | |
4633 | ||
4634 | for_each_sched_entity(se) { | |
4635 | cfs_rq = cfs_rq_of(se); | |
ab6cde26 | 4636 | put_prev_entity(cfs_rq, se); |
bf0f6f24 IM |
4637 | } |
4638 | } | |
4639 | ||
ac53db59 RR |
4640 | /* |
4641 | * sched_yield() is very simple | |
4642 | * | |
4643 | * The magic of dealing with the ->skip buddy is in pick_next_entity. | |
4644 | */ | |
4645 | static void yield_task_fair(struct rq *rq) | |
4646 | { | |
4647 | struct task_struct *curr = rq->curr; | |
4648 | struct cfs_rq *cfs_rq = task_cfs_rq(curr); | |
4649 | struct sched_entity *se = &curr->se; | |
4650 | ||
4651 | /* | |
4652 | * Are we the only task in the tree? | |
4653 | */ | |
4654 | if (unlikely(rq->nr_running == 1)) | |
4655 | return; | |
4656 | ||
4657 | clear_buddies(cfs_rq, se); | |
4658 | ||
4659 | if (curr->policy != SCHED_BATCH) { | |
4660 | update_rq_clock(rq); | |
4661 | /* | |
4662 | * Update run-time statistics of the 'current'. | |
4663 | */ | |
4664 | update_curr(cfs_rq); | |
916671c0 MG |
4665 | /* |
4666 | * Tell update_rq_clock() that we've just updated, | |
4667 | * so we don't do microscopic update in schedule() | |
4668 | * and double the fastpath cost. | |
4669 | */ | |
4670 | rq->skip_clock_update = 1; | |
ac53db59 RR |
4671 | } |
4672 | ||
4673 | set_skip_buddy(se); | |
4674 | } | |
4675 | ||
d95f4122 MG |
4676 | static bool yield_to_task_fair(struct rq *rq, struct task_struct *p, bool preempt) |
4677 | { | |
4678 | struct sched_entity *se = &p->se; | |
4679 | ||
5238cdd3 PT |
4680 | /* throttled hierarchies are not runnable */ |
4681 | if (!se->on_rq || throttled_hierarchy(cfs_rq_of(se))) | |
d95f4122 MG |
4682 | return false; |
4683 | ||
4684 | /* Tell the scheduler that we'd really like pse to run next. */ | |
4685 | set_next_buddy(se); | |
4686 | ||
d95f4122 MG |
4687 | yield_task_fair(rq); |
4688 | ||
4689 | return true; | |
4690 | } | |
4691 | ||
681f3e68 | 4692 | #ifdef CONFIG_SMP |
bf0f6f24 | 4693 | /************************************************** |
e9c84cb8 PZ |
4694 | * Fair scheduling class load-balancing methods. |
4695 | * | |
4696 | * BASICS | |
4697 | * | |
4698 | * The purpose of load-balancing is to achieve the same basic fairness the | |
4699 | * per-cpu scheduler provides, namely provide a proportional amount of compute | |
4700 | * time to each task. This is expressed in the following equation: | |
4701 | * | |
4702 | * W_i,n/P_i == W_j,n/P_j for all i,j (1) | |
4703 | * | |
4704 | * Where W_i,n is the n-th weight average for cpu i. The instantaneous weight | |
4705 | * W_i,0 is defined as: | |
4706 | * | |
4707 | * W_i,0 = \Sum_j w_i,j (2) | |
4708 | * | |
4709 | * Where w_i,j is the weight of the j-th runnable task on cpu i. This weight | |
4710 | * is derived from the nice value as per prio_to_weight[]. | |
4711 | * | |
4712 | * The weight average is an exponential decay average of the instantaneous | |
4713 | * weight: | |
4714 | * | |
4715 | * W'_i,n = (2^n - 1) / 2^n * W_i,n + 1 / 2^n * W_i,0 (3) | |
4716 | * | |
4717 | * P_i is the cpu power (or compute capacity) of cpu i, typically it is the | |
4718 | * fraction of 'recent' time available for SCHED_OTHER task execution. But it | |
4719 | * can also include other factors [XXX]. | |
4720 | * | |
4721 | * To achieve this balance we define a measure of imbalance which follows | |
4722 | * directly from (1): | |
4723 | * | |
4724 | * imb_i,j = max{ avg(W/P), W_i/P_i } - min{ avg(W/P), W_j/P_j } (4) | |
4725 | * | |
4726 | * We them move tasks around to minimize the imbalance. In the continuous | |
4727 | * function space it is obvious this converges, in the discrete case we get | |
4728 | * a few fun cases generally called infeasible weight scenarios. | |
4729 | * | |
4730 | * [XXX expand on: | |
4731 | * - infeasible weights; | |
4732 | * - local vs global optima in the discrete case. ] | |
4733 | * | |
4734 | * | |
4735 | * SCHED DOMAINS | |
4736 | * | |
4737 | * In order to solve the imbalance equation (4), and avoid the obvious O(n^2) | |
4738 | * for all i,j solution, we create a tree of cpus that follows the hardware | |
4739 | * topology where each level pairs two lower groups (or better). This results | |
4740 | * in O(log n) layers. Furthermore we reduce the number of cpus going up the | |
4741 | * tree to only the first of the previous level and we decrease the frequency | |
4742 | * of load-balance at each level inv. proportional to the number of cpus in | |
4743 | * the groups. | |
4744 | * | |
4745 | * This yields: | |
4746 | * | |
4747 | * log_2 n 1 n | |
4748 | * \Sum { --- * --- * 2^i } = O(n) (5) | |
4749 | * i = 0 2^i 2^i | |
4750 | * `- size of each group | |
4751 | * | | `- number of cpus doing load-balance | |
4752 | * | `- freq | |
4753 | * `- sum over all levels | |
4754 | * | |
4755 | * Coupled with a limit on how many tasks we can migrate every balance pass, | |
4756 | * this makes (5) the runtime complexity of the balancer. | |
4757 | * | |
4758 | * An important property here is that each CPU is still (indirectly) connected | |
4759 | * to every other cpu in at most O(log n) steps: | |
4760 | * | |
4761 | * The adjacency matrix of the resulting graph is given by: | |
4762 | * | |
4763 | * log_2 n | |
4764 | * A_i,j = \Union (i % 2^k == 0) && i / 2^(k+1) == j / 2^(k+1) (6) | |
4765 | * k = 0 | |
4766 | * | |
4767 | * And you'll find that: | |
4768 | * | |
4769 | * A^(log_2 n)_i,j != 0 for all i,j (7) | |
4770 | * | |
4771 | * Showing there's indeed a path between every cpu in at most O(log n) steps. | |
4772 | * The task movement gives a factor of O(m), giving a convergence complexity | |
4773 | * of: | |
4774 | * | |
4775 | * O(nm log n), n := nr_cpus, m := nr_tasks (8) | |
4776 | * | |
4777 | * | |
4778 | * WORK CONSERVING | |
4779 | * | |
4780 | * In order to avoid CPUs going idle while there's still work to do, new idle | |
4781 | * balancing is more aggressive and has the newly idle cpu iterate up the domain | |
4782 | * tree itself instead of relying on other CPUs to bring it work. | |
4783 | * | |
4784 | * This adds some complexity to both (5) and (8) but it reduces the total idle | |
4785 | * time. | |
4786 | * | |
4787 | * [XXX more?] | |
4788 | * | |
4789 | * | |
4790 | * CGROUPS | |
4791 | * | |
4792 | * Cgroups make a horror show out of (2), instead of a simple sum we get: | |
4793 | * | |
4794 | * s_k,i | |
4795 | * W_i,0 = \Sum_j \Prod_k w_k * ----- (9) | |
4796 | * S_k | |
4797 | * | |
4798 | * Where | |
4799 | * | |
4800 | * s_k,i = \Sum_j w_i,j,k and S_k = \Sum_i s_k,i (10) | |
4801 | * | |
4802 | * w_i,j,k is the weight of the j-th runnable task in the k-th cgroup on cpu i. | |
4803 | * | |
4804 | * The big problem is S_k, its a global sum needed to compute a local (W_i) | |
4805 | * property. | |
4806 | * | |
4807 | * [XXX write more on how we solve this.. _after_ merging pjt's patches that | |
4808 | * rewrite all of this once again.] | |
4809 | */ | |
bf0f6f24 | 4810 | |
ed387b78 HS |
4811 | static unsigned long __read_mostly max_load_balance_interval = HZ/10; |
4812 | ||
0ec8aa00 PZ |
4813 | enum fbq_type { regular, remote, all }; |
4814 | ||
ddcdf6e7 | 4815 | #define LBF_ALL_PINNED 0x01 |
367456c7 | 4816 | #define LBF_NEED_BREAK 0x02 |
6263322c PZ |
4817 | #define LBF_DST_PINNED 0x04 |
4818 | #define LBF_SOME_PINNED 0x08 | |
ddcdf6e7 PZ |
4819 | |
4820 | struct lb_env { | |
4821 | struct sched_domain *sd; | |
4822 | ||
ddcdf6e7 | 4823 | struct rq *src_rq; |
85c1e7da | 4824 | int src_cpu; |
ddcdf6e7 PZ |
4825 | |
4826 | int dst_cpu; | |
4827 | struct rq *dst_rq; | |
4828 | ||
88b8dac0 SV |
4829 | struct cpumask *dst_grpmask; |
4830 | int new_dst_cpu; | |
ddcdf6e7 | 4831 | enum cpu_idle_type idle; |
bd939f45 | 4832 | long imbalance; |
b9403130 MW |
4833 | /* The set of CPUs under consideration for load-balancing */ |
4834 | struct cpumask *cpus; | |
4835 | ||
ddcdf6e7 | 4836 | unsigned int flags; |
367456c7 PZ |
4837 | |
4838 | unsigned int loop; | |
4839 | unsigned int loop_break; | |
4840 | unsigned int loop_max; | |
0ec8aa00 PZ |
4841 | |
4842 | enum fbq_type fbq_type; | |
ddcdf6e7 PZ |
4843 | }; |
4844 | ||
1e3c88bd | 4845 | /* |
ddcdf6e7 | 4846 | * move_task - move a task from one runqueue to another runqueue. |
1e3c88bd PZ |
4847 | * Both runqueues must be locked. |
4848 | */ | |
ddcdf6e7 | 4849 | static void move_task(struct task_struct *p, struct lb_env *env) |
1e3c88bd | 4850 | { |
ddcdf6e7 PZ |
4851 | deactivate_task(env->src_rq, p, 0); |
4852 | set_task_cpu(p, env->dst_cpu); | |
4853 | activate_task(env->dst_rq, p, 0); | |
4854 | check_preempt_curr(env->dst_rq, p, 0); | |
1e3c88bd PZ |
4855 | } |
4856 | ||
029632fb PZ |
4857 | /* |
4858 | * Is this task likely cache-hot: | |
4859 | */ | |
4860 | static int | |
4861 | task_hot(struct task_struct *p, u64 now, struct sched_domain *sd) | |
4862 | { | |
4863 | s64 delta; | |
4864 | ||
4865 | if (p->sched_class != &fair_sched_class) | |
4866 | return 0; | |
4867 | ||
4868 | if (unlikely(p->policy == SCHED_IDLE)) | |
4869 | return 0; | |
4870 | ||
4871 | /* | |
4872 | * Buddy candidates are cache hot: | |
4873 | */ | |
4874 | if (sched_feat(CACHE_HOT_BUDDY) && this_rq()->nr_running && | |
4875 | (&p->se == cfs_rq_of(&p->se)->next || | |
4876 | &p->se == cfs_rq_of(&p->se)->last)) | |
4877 | return 1; | |
4878 | ||
4879 | if (sysctl_sched_migration_cost == -1) | |
4880 | return 1; | |
4881 | if (sysctl_sched_migration_cost == 0) | |
4882 | return 0; | |
4883 | ||
4884 | delta = now - p->se.exec_start; | |
4885 | ||
4886 | return delta < (s64)sysctl_sched_migration_cost; | |
4887 | } | |
4888 | ||
3a7053b3 MG |
4889 | #ifdef CONFIG_NUMA_BALANCING |
4890 | /* Returns true if the destination node has incurred more faults */ | |
4891 | static bool migrate_improves_locality(struct task_struct *p, struct lb_env *env) | |
4892 | { | |
4893 | int src_nid, dst_nid; | |
4894 | ||
ff1df896 | 4895 | if (!sched_feat(NUMA_FAVOUR_HIGHER) || !p->numa_faults_memory || |
3a7053b3 MG |
4896 | !(env->sd->flags & SD_NUMA)) { |
4897 | return false; | |
4898 | } | |
4899 | ||
4900 | src_nid = cpu_to_node(env->src_cpu); | |
4901 | dst_nid = cpu_to_node(env->dst_cpu); | |
4902 | ||
83e1d2cd | 4903 | if (src_nid == dst_nid) |
3a7053b3 MG |
4904 | return false; |
4905 | ||
83e1d2cd MG |
4906 | /* Always encourage migration to the preferred node. */ |
4907 | if (dst_nid == p->numa_preferred_nid) | |
4908 | return true; | |
4909 | ||
887c290e RR |
4910 | /* If both task and group weight improve, this move is a winner. */ |
4911 | if (task_weight(p, dst_nid) > task_weight(p, src_nid) && | |
4912 | group_weight(p, dst_nid) > group_weight(p, src_nid)) | |
3a7053b3 MG |
4913 | return true; |
4914 | ||
4915 | return false; | |
4916 | } | |
7a0f3083 MG |
4917 | |
4918 | ||
4919 | static bool migrate_degrades_locality(struct task_struct *p, struct lb_env *env) | |
4920 | { | |
4921 | int src_nid, dst_nid; | |
4922 | ||
4923 | if (!sched_feat(NUMA) || !sched_feat(NUMA_RESIST_LOWER)) | |
4924 | return false; | |
4925 | ||
ff1df896 | 4926 | if (!p->numa_faults_memory || !(env->sd->flags & SD_NUMA)) |
7a0f3083 MG |
4927 | return false; |
4928 | ||
4929 | src_nid = cpu_to_node(env->src_cpu); | |
4930 | dst_nid = cpu_to_node(env->dst_cpu); | |
4931 | ||
83e1d2cd | 4932 | if (src_nid == dst_nid) |
7a0f3083 MG |
4933 | return false; |
4934 | ||
83e1d2cd MG |
4935 | /* Migrating away from the preferred node is always bad. */ |
4936 | if (src_nid == p->numa_preferred_nid) | |
4937 | return true; | |
4938 | ||
887c290e RR |
4939 | /* If either task or group weight get worse, don't do it. */ |
4940 | if (task_weight(p, dst_nid) < task_weight(p, src_nid) || | |
4941 | group_weight(p, dst_nid) < group_weight(p, src_nid)) | |
7a0f3083 MG |
4942 | return true; |
4943 | ||
4944 | return false; | |
4945 | } | |
4946 | ||
3a7053b3 MG |
4947 | #else |
4948 | static inline bool migrate_improves_locality(struct task_struct *p, | |
4949 | struct lb_env *env) | |
4950 | { | |
4951 | return false; | |
4952 | } | |
7a0f3083 MG |
4953 | |
4954 | static inline bool migrate_degrades_locality(struct task_struct *p, | |
4955 | struct lb_env *env) | |
4956 | { | |
4957 | return false; | |
4958 | } | |
3a7053b3 MG |
4959 | #endif |
4960 | ||
1e3c88bd PZ |
4961 | /* |
4962 | * can_migrate_task - may task p from runqueue rq be migrated to this_cpu? | |
4963 | */ | |
4964 | static | |
8e45cb54 | 4965 | int can_migrate_task(struct task_struct *p, struct lb_env *env) |
1e3c88bd PZ |
4966 | { |
4967 | int tsk_cache_hot = 0; | |
4968 | /* | |
4969 | * We do not migrate tasks that are: | |
d3198084 | 4970 | * 1) throttled_lb_pair, or |
1e3c88bd | 4971 | * 2) cannot be migrated to this CPU due to cpus_allowed, or |
d3198084 JK |
4972 | * 3) running (obviously), or |
4973 | * 4) are cache-hot on their current CPU. | |
1e3c88bd | 4974 | */ |
d3198084 JK |
4975 | if (throttled_lb_pair(task_group(p), env->src_cpu, env->dst_cpu)) |
4976 | return 0; | |
4977 | ||
ddcdf6e7 | 4978 | if (!cpumask_test_cpu(env->dst_cpu, tsk_cpus_allowed(p))) { |
e02e60c1 | 4979 | int cpu; |
88b8dac0 | 4980 | |
41acab88 | 4981 | schedstat_inc(p, se.statistics.nr_failed_migrations_affine); |
88b8dac0 | 4982 | |
6263322c PZ |
4983 | env->flags |= LBF_SOME_PINNED; |
4984 | ||
88b8dac0 SV |
4985 | /* |
4986 | * Remember if this task can be migrated to any other cpu in | |
4987 | * our sched_group. We may want to revisit it if we couldn't | |
4988 | * meet load balance goals by pulling other tasks on src_cpu. | |
4989 | * | |
4990 | * Also avoid computing new_dst_cpu if we have already computed | |
4991 | * one in current iteration. | |
4992 | */ | |
6263322c | 4993 | if (!env->dst_grpmask || (env->flags & LBF_DST_PINNED)) |
88b8dac0 SV |
4994 | return 0; |
4995 | ||
e02e60c1 JK |
4996 | /* Prevent to re-select dst_cpu via env's cpus */ |
4997 | for_each_cpu_and(cpu, env->dst_grpmask, env->cpus) { | |
4998 | if (cpumask_test_cpu(cpu, tsk_cpus_allowed(p))) { | |
6263322c | 4999 | env->flags |= LBF_DST_PINNED; |
e02e60c1 JK |
5000 | env->new_dst_cpu = cpu; |
5001 | break; | |
5002 | } | |
88b8dac0 | 5003 | } |
e02e60c1 | 5004 | |
1e3c88bd PZ |
5005 | return 0; |
5006 | } | |
88b8dac0 SV |
5007 | |
5008 | /* Record that we found atleast one task that could run on dst_cpu */ | |
8e45cb54 | 5009 | env->flags &= ~LBF_ALL_PINNED; |
1e3c88bd | 5010 | |
ddcdf6e7 | 5011 | if (task_running(env->src_rq, p)) { |
41acab88 | 5012 | schedstat_inc(p, se.statistics.nr_failed_migrations_running); |
1e3c88bd PZ |
5013 | return 0; |
5014 | } | |
5015 | ||
5016 | /* | |
5017 | * Aggressive migration if: | |
3a7053b3 MG |
5018 | * 1) destination numa is preferred |
5019 | * 2) task is cache cold, or | |
5020 | * 3) too many balance attempts have failed. | |
1e3c88bd | 5021 | */ |
78becc27 | 5022 | tsk_cache_hot = task_hot(p, rq_clock_task(env->src_rq), env->sd); |
7a0f3083 MG |
5023 | if (!tsk_cache_hot) |
5024 | tsk_cache_hot = migrate_degrades_locality(p, env); | |
3a7053b3 MG |
5025 | |
5026 | if (migrate_improves_locality(p, env)) { | |
5027 | #ifdef CONFIG_SCHEDSTATS | |
5028 | if (tsk_cache_hot) { | |
5029 | schedstat_inc(env->sd, lb_hot_gained[env->idle]); | |
5030 | schedstat_inc(p, se.statistics.nr_forced_migrations); | |
5031 | } | |
5032 | #endif | |
5033 | return 1; | |
5034 | } | |
5035 | ||
1e3c88bd | 5036 | if (!tsk_cache_hot || |
8e45cb54 | 5037 | env->sd->nr_balance_failed > env->sd->cache_nice_tries) { |
4e2dcb73 | 5038 | |
1e3c88bd | 5039 | if (tsk_cache_hot) { |
8e45cb54 | 5040 | schedstat_inc(env->sd, lb_hot_gained[env->idle]); |
41acab88 | 5041 | schedstat_inc(p, se.statistics.nr_forced_migrations); |
1e3c88bd | 5042 | } |
4e2dcb73 | 5043 | |
1e3c88bd PZ |
5044 | return 1; |
5045 | } | |
5046 | ||
4e2dcb73 ZH |
5047 | schedstat_inc(p, se.statistics.nr_failed_migrations_hot); |
5048 | return 0; | |
1e3c88bd PZ |
5049 | } |
5050 | ||
897c395f PZ |
5051 | /* |
5052 | * move_one_task tries to move exactly one task from busiest to this_rq, as | |
5053 | * part of active balancing operations within "domain". | |
5054 | * Returns 1 if successful and 0 otherwise. | |
5055 | * | |
5056 | * Called with both runqueues locked. | |
5057 | */ | |
8e45cb54 | 5058 | static int move_one_task(struct lb_env *env) |
897c395f PZ |
5059 | { |
5060 | struct task_struct *p, *n; | |
897c395f | 5061 | |
367456c7 | 5062 | list_for_each_entry_safe(p, n, &env->src_rq->cfs_tasks, se.group_node) { |
367456c7 PZ |
5063 | if (!can_migrate_task(p, env)) |
5064 | continue; | |
897c395f | 5065 | |
367456c7 PZ |
5066 | move_task(p, env); |
5067 | /* | |
5068 | * Right now, this is only the second place move_task() | |
5069 | * is called, so we can safely collect move_task() | |
5070 | * stats here rather than inside move_task(). | |
5071 | */ | |
5072 | schedstat_inc(env->sd, lb_gained[env->idle]); | |
5073 | return 1; | |
897c395f | 5074 | } |
897c395f PZ |
5075 | return 0; |
5076 | } | |
5077 | ||
eb95308e PZ |
5078 | static const unsigned int sched_nr_migrate_break = 32; |
5079 | ||
5d6523eb | 5080 | /* |
bd939f45 | 5081 | * move_tasks tries to move up to imbalance weighted load from busiest to |
5d6523eb PZ |
5082 | * this_rq, as part of a balancing operation within domain "sd". |
5083 | * Returns 1 if successful and 0 otherwise. | |
5084 | * | |
5085 | * Called with both runqueues locked. | |
5086 | */ | |
5087 | static int move_tasks(struct lb_env *env) | |
1e3c88bd | 5088 | { |
5d6523eb PZ |
5089 | struct list_head *tasks = &env->src_rq->cfs_tasks; |
5090 | struct task_struct *p; | |
367456c7 PZ |
5091 | unsigned long load; |
5092 | int pulled = 0; | |
1e3c88bd | 5093 | |
bd939f45 | 5094 | if (env->imbalance <= 0) |
5d6523eb | 5095 | return 0; |
1e3c88bd | 5096 | |
5d6523eb PZ |
5097 | while (!list_empty(tasks)) { |
5098 | p = list_first_entry(tasks, struct task_struct, se.group_node); | |
1e3c88bd | 5099 | |
367456c7 PZ |
5100 | env->loop++; |
5101 | /* We've more or less seen every task there is, call it quits */ | |
5d6523eb | 5102 | if (env->loop > env->loop_max) |
367456c7 | 5103 | break; |
5d6523eb PZ |
5104 | |
5105 | /* take a breather every nr_migrate tasks */ | |
367456c7 | 5106 | if (env->loop > env->loop_break) { |
eb95308e | 5107 | env->loop_break += sched_nr_migrate_break; |
8e45cb54 | 5108 | env->flags |= LBF_NEED_BREAK; |
ee00e66f | 5109 | break; |
a195f004 | 5110 | } |
1e3c88bd | 5111 | |
d3198084 | 5112 | if (!can_migrate_task(p, env)) |
367456c7 PZ |
5113 | goto next; |
5114 | ||
5115 | load = task_h_load(p); | |
5d6523eb | 5116 | |
eb95308e | 5117 | if (sched_feat(LB_MIN) && load < 16 && !env->sd->nr_balance_failed) |
367456c7 PZ |
5118 | goto next; |
5119 | ||
bd939f45 | 5120 | if ((load / 2) > env->imbalance) |
367456c7 | 5121 | goto next; |
1e3c88bd | 5122 | |
ddcdf6e7 | 5123 | move_task(p, env); |
ee00e66f | 5124 | pulled++; |
bd939f45 | 5125 | env->imbalance -= load; |
1e3c88bd PZ |
5126 | |
5127 | #ifdef CONFIG_PREEMPT | |
ee00e66f PZ |
5128 | /* |
5129 | * NEWIDLE balancing is a source of latency, so preemptible | |
5130 | * kernels will stop after the first task is pulled to minimize | |
5131 | * the critical section. | |
5132 | */ | |
5d6523eb | 5133 | if (env->idle == CPU_NEWLY_IDLE) |
ee00e66f | 5134 | break; |
1e3c88bd PZ |
5135 | #endif |
5136 | ||
ee00e66f PZ |
5137 | /* |
5138 | * We only want to steal up to the prescribed amount of | |
5139 | * weighted load. | |
5140 | */ | |
bd939f45 | 5141 | if (env->imbalance <= 0) |
ee00e66f | 5142 | break; |
367456c7 PZ |
5143 | |
5144 | continue; | |
5145 | next: | |
5d6523eb | 5146 | list_move_tail(&p->se.group_node, tasks); |
1e3c88bd | 5147 | } |
5d6523eb | 5148 | |
1e3c88bd | 5149 | /* |
ddcdf6e7 PZ |
5150 | * Right now, this is one of only two places move_task() is called, |
5151 | * so we can safely collect move_task() stats here rather than | |
5152 | * inside move_task(). | |
1e3c88bd | 5153 | */ |
8e45cb54 | 5154 | schedstat_add(env->sd, lb_gained[env->idle], pulled); |
1e3c88bd | 5155 | |
5d6523eb | 5156 | return pulled; |
1e3c88bd PZ |
5157 | } |
5158 | ||
230059de | 5159 | #ifdef CONFIG_FAIR_GROUP_SCHED |
9e3081ca PZ |
5160 | /* |
5161 | * update tg->load_weight by folding this cpu's load_avg | |
5162 | */ | |
48a16753 | 5163 | static void __update_blocked_averages_cpu(struct task_group *tg, int cpu) |
9e3081ca | 5164 | { |
48a16753 PT |
5165 | struct sched_entity *se = tg->se[cpu]; |
5166 | struct cfs_rq *cfs_rq = tg->cfs_rq[cpu]; | |
9e3081ca | 5167 | |
48a16753 PT |
5168 | /* throttled entities do not contribute to load */ |
5169 | if (throttled_hierarchy(cfs_rq)) | |
5170 | return; | |
9e3081ca | 5171 | |
aff3e498 | 5172 | update_cfs_rq_blocked_load(cfs_rq, 1); |
9e3081ca | 5173 | |
82958366 PT |
5174 | if (se) { |
5175 | update_entity_load_avg(se, 1); | |
5176 | /* | |
5177 | * We pivot on our runnable average having decayed to zero for | |
5178 | * list removal. This generally implies that all our children | |
5179 | * have also been removed (modulo rounding error or bandwidth | |
5180 | * control); however, such cases are rare and we can fix these | |
5181 | * at enqueue. | |
5182 | * | |
5183 | * TODO: fix up out-of-order children on enqueue. | |
5184 | */ | |
5185 | if (!se->avg.runnable_avg_sum && !cfs_rq->nr_running) | |
5186 | list_del_leaf_cfs_rq(cfs_rq); | |
5187 | } else { | |
48a16753 | 5188 | struct rq *rq = rq_of(cfs_rq); |
82958366 PT |
5189 | update_rq_runnable_avg(rq, rq->nr_running); |
5190 | } | |
9e3081ca PZ |
5191 | } |
5192 | ||
48a16753 | 5193 | static void update_blocked_averages(int cpu) |
9e3081ca | 5194 | { |
9e3081ca | 5195 | struct rq *rq = cpu_rq(cpu); |
48a16753 PT |
5196 | struct cfs_rq *cfs_rq; |
5197 | unsigned long flags; | |
9e3081ca | 5198 | |
48a16753 PT |
5199 | raw_spin_lock_irqsave(&rq->lock, flags); |
5200 | update_rq_clock(rq); | |
9763b67f PZ |
5201 | /* |
5202 | * Iterates the task_group tree in a bottom up fashion, see | |
5203 | * list_add_leaf_cfs_rq() for details. | |
5204 | */ | |
64660c86 | 5205 | for_each_leaf_cfs_rq(rq, cfs_rq) { |
48a16753 PT |
5206 | /* |
5207 | * Note: We may want to consider periodically releasing | |
5208 | * rq->lock about these updates so that creating many task | |
5209 | * groups does not result in continually extending hold time. | |
5210 | */ | |
5211 | __update_blocked_averages_cpu(cfs_rq->tg, rq->cpu); | |
64660c86 | 5212 | } |
48a16753 PT |
5213 | |
5214 | raw_spin_unlock_irqrestore(&rq->lock, flags); | |
9e3081ca PZ |
5215 | } |
5216 | ||
9763b67f | 5217 | /* |
68520796 | 5218 | * Compute the hierarchical load factor for cfs_rq and all its ascendants. |
9763b67f PZ |
5219 | * This needs to be done in a top-down fashion because the load of a child |
5220 | * group is a fraction of its parents load. | |
5221 | */ | |
68520796 | 5222 | static void update_cfs_rq_h_load(struct cfs_rq *cfs_rq) |
9763b67f | 5223 | { |
68520796 VD |
5224 | struct rq *rq = rq_of(cfs_rq); |
5225 | struct sched_entity *se = cfs_rq->tg->se[cpu_of(rq)]; | |
a35b6466 | 5226 | unsigned long now = jiffies; |
68520796 | 5227 | unsigned long load; |
a35b6466 | 5228 | |
68520796 | 5229 | if (cfs_rq->last_h_load_update == now) |
a35b6466 PZ |
5230 | return; |
5231 | ||
68520796 VD |
5232 | cfs_rq->h_load_next = NULL; |
5233 | for_each_sched_entity(se) { | |
5234 | cfs_rq = cfs_rq_of(se); | |
5235 | cfs_rq->h_load_next = se; | |
5236 | if (cfs_rq->last_h_load_update == now) | |
5237 | break; | |
5238 | } | |
a35b6466 | 5239 | |
68520796 | 5240 | if (!se) { |
7e3115ef | 5241 | cfs_rq->h_load = cfs_rq->runnable_load_avg; |
68520796 VD |
5242 | cfs_rq->last_h_load_update = now; |
5243 | } | |
5244 | ||
5245 | while ((se = cfs_rq->h_load_next) != NULL) { | |
5246 | load = cfs_rq->h_load; | |
5247 | load = div64_ul(load * se->avg.load_avg_contrib, | |
5248 | cfs_rq->runnable_load_avg + 1); | |
5249 | cfs_rq = group_cfs_rq(se); | |
5250 | cfs_rq->h_load = load; | |
5251 | cfs_rq->last_h_load_update = now; | |
5252 | } | |
9763b67f PZ |
5253 | } |
5254 | ||
367456c7 | 5255 | static unsigned long task_h_load(struct task_struct *p) |
230059de | 5256 | { |
367456c7 | 5257 | struct cfs_rq *cfs_rq = task_cfs_rq(p); |
230059de | 5258 | |
68520796 | 5259 | update_cfs_rq_h_load(cfs_rq); |
a003a25b AS |
5260 | return div64_ul(p->se.avg.load_avg_contrib * cfs_rq->h_load, |
5261 | cfs_rq->runnable_load_avg + 1); | |
230059de PZ |
5262 | } |
5263 | #else | |
48a16753 | 5264 | static inline void update_blocked_averages(int cpu) |
9e3081ca PZ |
5265 | { |
5266 | } | |
5267 | ||
367456c7 | 5268 | static unsigned long task_h_load(struct task_struct *p) |
1e3c88bd | 5269 | { |
a003a25b | 5270 | return p->se.avg.load_avg_contrib; |
1e3c88bd | 5271 | } |
230059de | 5272 | #endif |
1e3c88bd | 5273 | |
1e3c88bd | 5274 | /********** Helpers for find_busiest_group ************************/ |
1e3c88bd PZ |
5275 | /* |
5276 | * sg_lb_stats - stats of a sched_group required for load_balancing | |
5277 | */ | |
5278 | struct sg_lb_stats { | |
5279 | unsigned long avg_load; /*Avg load across the CPUs of the group */ | |
5280 | unsigned long group_load; /* Total load over the CPUs of the group */ | |
1e3c88bd | 5281 | unsigned long sum_weighted_load; /* Weighted load of group's tasks */ |
56cf515b | 5282 | unsigned long load_per_task; |
3ae11c90 | 5283 | unsigned long group_power; |
147c5fc2 PZ |
5284 | unsigned int sum_nr_running; /* Nr tasks running in the group */ |
5285 | unsigned int group_capacity; | |
5286 | unsigned int idle_cpus; | |
5287 | unsigned int group_weight; | |
1e3c88bd | 5288 | int group_imb; /* Is there an imbalance in the group ? */ |
fab47622 | 5289 | int group_has_capacity; /* Is there extra capacity in the group? */ |
0ec8aa00 PZ |
5290 | #ifdef CONFIG_NUMA_BALANCING |
5291 | unsigned int nr_numa_running; | |
5292 | unsigned int nr_preferred_running; | |
5293 | #endif | |
1e3c88bd PZ |
5294 | }; |
5295 | ||
56cf515b JK |
5296 | /* |
5297 | * sd_lb_stats - Structure to store the statistics of a sched_domain | |
5298 | * during load balancing. | |
5299 | */ | |
5300 | struct sd_lb_stats { | |
5301 | struct sched_group *busiest; /* Busiest group in this sd */ | |
5302 | struct sched_group *local; /* Local group in this sd */ | |
5303 | unsigned long total_load; /* Total load of all groups in sd */ | |
5304 | unsigned long total_pwr; /* Total power of all groups in sd */ | |
5305 | unsigned long avg_load; /* Average load across all groups in sd */ | |
5306 | ||
56cf515b | 5307 | struct sg_lb_stats busiest_stat;/* Statistics of the busiest group */ |
147c5fc2 | 5308 | struct sg_lb_stats local_stat; /* Statistics of the local group */ |
56cf515b JK |
5309 | }; |
5310 | ||
147c5fc2 PZ |
5311 | static inline void init_sd_lb_stats(struct sd_lb_stats *sds) |
5312 | { | |
5313 | /* | |
5314 | * Skimp on the clearing to avoid duplicate work. We can avoid clearing | |
5315 | * local_stat because update_sg_lb_stats() does a full clear/assignment. | |
5316 | * We must however clear busiest_stat::avg_load because | |
5317 | * update_sd_pick_busiest() reads this before assignment. | |
5318 | */ | |
5319 | *sds = (struct sd_lb_stats){ | |
5320 | .busiest = NULL, | |
5321 | .local = NULL, | |
5322 | .total_load = 0UL, | |
5323 | .total_pwr = 0UL, | |
5324 | .busiest_stat = { | |
5325 | .avg_load = 0UL, | |
5326 | }, | |
5327 | }; | |
5328 | } | |
5329 | ||
1e3c88bd PZ |
5330 | /** |
5331 | * get_sd_load_idx - Obtain the load index for a given sched domain. | |
5332 | * @sd: The sched_domain whose load_idx is to be obtained. | |
ed1b7732 | 5333 | * @idle: The idle status of the CPU for whose sd load_idx is obtained. |
e69f6186 YB |
5334 | * |
5335 | * Return: The load index. | |
1e3c88bd PZ |
5336 | */ |
5337 | static inline int get_sd_load_idx(struct sched_domain *sd, | |
5338 | enum cpu_idle_type idle) | |
5339 | { | |
5340 | int load_idx; | |
5341 | ||
5342 | switch (idle) { | |
5343 | case CPU_NOT_IDLE: | |
5344 | load_idx = sd->busy_idx; | |
5345 | break; | |
5346 | ||
5347 | case CPU_NEWLY_IDLE: | |
5348 | load_idx = sd->newidle_idx; | |
5349 | break; | |
5350 | default: | |
5351 | load_idx = sd->idle_idx; | |
5352 | break; | |
5353 | } | |
5354 | ||
5355 | return load_idx; | |
5356 | } | |
5357 | ||
15f803c9 | 5358 | static unsigned long default_scale_freq_power(struct sched_domain *sd, int cpu) |
1e3c88bd | 5359 | { |
1399fa78 | 5360 | return SCHED_POWER_SCALE; |
1e3c88bd PZ |
5361 | } |
5362 | ||
5363 | unsigned long __weak arch_scale_freq_power(struct sched_domain *sd, int cpu) | |
5364 | { | |
5365 | return default_scale_freq_power(sd, cpu); | |
5366 | } | |
5367 | ||
15f803c9 | 5368 | static unsigned long default_scale_smt_power(struct sched_domain *sd, int cpu) |
1e3c88bd | 5369 | { |
669c55e9 | 5370 | unsigned long weight = sd->span_weight; |
1e3c88bd PZ |
5371 | unsigned long smt_gain = sd->smt_gain; |
5372 | ||
5373 | smt_gain /= weight; | |
5374 | ||
5375 | return smt_gain; | |
5376 | } | |
5377 | ||
5378 | unsigned long __weak arch_scale_smt_power(struct sched_domain *sd, int cpu) | |
5379 | { | |
5380 | return default_scale_smt_power(sd, cpu); | |
5381 | } | |
5382 | ||
15f803c9 | 5383 | static unsigned long scale_rt_power(int cpu) |
1e3c88bd PZ |
5384 | { |
5385 | struct rq *rq = cpu_rq(cpu); | |
b654f7de | 5386 | u64 total, available, age_stamp, avg; |
1e3c88bd | 5387 | |
b654f7de PZ |
5388 | /* |
5389 | * Since we're reading these variables without serialization make sure | |
5390 | * we read them once before doing sanity checks on them. | |
5391 | */ | |
5392 | age_stamp = ACCESS_ONCE(rq->age_stamp); | |
5393 | avg = ACCESS_ONCE(rq->rt_avg); | |
5394 | ||
78becc27 | 5395 | total = sched_avg_period() + (rq_clock(rq) - age_stamp); |
aa483808 | 5396 | |
b654f7de | 5397 | if (unlikely(total < avg)) { |
aa483808 VP |
5398 | /* Ensures that power won't end up being negative */ |
5399 | available = 0; | |
5400 | } else { | |
b654f7de | 5401 | available = total - avg; |
aa483808 | 5402 | } |
1e3c88bd | 5403 | |
1399fa78 NR |
5404 | if (unlikely((s64)total < SCHED_POWER_SCALE)) |
5405 | total = SCHED_POWER_SCALE; | |
1e3c88bd | 5406 | |
1399fa78 | 5407 | total >>= SCHED_POWER_SHIFT; |
1e3c88bd PZ |
5408 | |
5409 | return div_u64(available, total); | |
5410 | } | |
5411 | ||
5412 | static void update_cpu_power(struct sched_domain *sd, int cpu) | |
5413 | { | |
669c55e9 | 5414 | unsigned long weight = sd->span_weight; |
1399fa78 | 5415 | unsigned long power = SCHED_POWER_SCALE; |
1e3c88bd PZ |
5416 | struct sched_group *sdg = sd->groups; |
5417 | ||
1e3c88bd PZ |
5418 | if ((sd->flags & SD_SHARE_CPUPOWER) && weight > 1) { |
5419 | if (sched_feat(ARCH_POWER)) | |
5420 | power *= arch_scale_smt_power(sd, cpu); | |
5421 | else | |
5422 | power *= default_scale_smt_power(sd, cpu); | |
5423 | ||
1399fa78 | 5424 | power >>= SCHED_POWER_SHIFT; |
1e3c88bd PZ |
5425 | } |
5426 | ||
9c3f75cb | 5427 | sdg->sgp->power_orig = power; |
9d5efe05 SV |
5428 | |
5429 | if (sched_feat(ARCH_POWER)) | |
5430 | power *= arch_scale_freq_power(sd, cpu); | |
5431 | else | |
5432 | power *= default_scale_freq_power(sd, cpu); | |
5433 | ||
1399fa78 | 5434 | power >>= SCHED_POWER_SHIFT; |
9d5efe05 | 5435 | |
1e3c88bd | 5436 | power *= scale_rt_power(cpu); |
1399fa78 | 5437 | power >>= SCHED_POWER_SHIFT; |
1e3c88bd PZ |
5438 | |
5439 | if (!power) | |
5440 | power = 1; | |
5441 | ||
e51fd5e2 | 5442 | cpu_rq(cpu)->cpu_power = power; |
9c3f75cb | 5443 | sdg->sgp->power = power; |
1e3c88bd PZ |
5444 | } |
5445 | ||
029632fb | 5446 | void update_group_power(struct sched_domain *sd, int cpu) |
1e3c88bd PZ |
5447 | { |
5448 | struct sched_domain *child = sd->child; | |
5449 | struct sched_group *group, *sdg = sd->groups; | |
863bffc8 | 5450 | unsigned long power, power_orig; |
4ec4412e VG |
5451 | unsigned long interval; |
5452 | ||
5453 | interval = msecs_to_jiffies(sd->balance_interval); | |
5454 | interval = clamp(interval, 1UL, max_load_balance_interval); | |
5455 | sdg->sgp->next_update = jiffies + interval; | |
1e3c88bd PZ |
5456 | |
5457 | if (!child) { | |
5458 | update_cpu_power(sd, cpu); | |
5459 | return; | |
5460 | } | |
5461 | ||
863bffc8 | 5462 | power_orig = power = 0; |
1e3c88bd | 5463 | |
74a5ce20 PZ |
5464 | if (child->flags & SD_OVERLAP) { |
5465 | /* | |
5466 | * SD_OVERLAP domains cannot assume that child groups | |
5467 | * span the current group. | |
5468 | */ | |
5469 | ||
863bffc8 | 5470 | for_each_cpu(cpu, sched_group_cpus(sdg)) { |
9abf24d4 SD |
5471 | struct sched_group_power *sgp; |
5472 | struct rq *rq = cpu_rq(cpu); | |
863bffc8 | 5473 | |
9abf24d4 SD |
5474 | /* |
5475 | * build_sched_domains() -> init_sched_groups_power() | |
5476 | * gets here before we've attached the domains to the | |
5477 | * runqueues. | |
5478 | * | |
5479 | * Use power_of(), which is set irrespective of domains | |
5480 | * in update_cpu_power(). | |
5481 | * | |
5482 | * This avoids power/power_orig from being 0 and | |
5483 | * causing divide-by-zero issues on boot. | |
5484 | * | |
5485 | * Runtime updates will correct power_orig. | |
5486 | */ | |
5487 | if (unlikely(!rq->sd)) { | |
5488 | power_orig += power_of(cpu); | |
5489 | power += power_of(cpu); | |
5490 | continue; | |
5491 | } | |
863bffc8 | 5492 | |
9abf24d4 SD |
5493 | sgp = rq->sd->groups->sgp; |
5494 | power_orig += sgp->power_orig; | |
5495 | power += sgp->power; | |
863bffc8 | 5496 | } |
74a5ce20 PZ |
5497 | } else { |
5498 | /* | |
5499 | * !SD_OVERLAP domains can assume that child groups | |
5500 | * span the current group. | |
5501 | */ | |
5502 | ||
5503 | group = child->groups; | |
5504 | do { | |
863bffc8 | 5505 | power_orig += group->sgp->power_orig; |
74a5ce20 PZ |
5506 | power += group->sgp->power; |
5507 | group = group->next; | |
5508 | } while (group != child->groups); | |
5509 | } | |
1e3c88bd | 5510 | |
863bffc8 PZ |
5511 | sdg->sgp->power_orig = power_orig; |
5512 | sdg->sgp->power = power; | |
1e3c88bd PZ |
5513 | } |
5514 | ||
9d5efe05 SV |
5515 | /* |
5516 | * Try and fix up capacity for tiny siblings, this is needed when | |
5517 | * things like SD_ASYM_PACKING need f_b_g to select another sibling | |
5518 | * which on its own isn't powerful enough. | |
5519 | * | |
5520 | * See update_sd_pick_busiest() and check_asym_packing(). | |
5521 | */ | |
5522 | static inline int | |
5523 | fix_small_capacity(struct sched_domain *sd, struct sched_group *group) | |
5524 | { | |
5525 | /* | |
1399fa78 | 5526 | * Only siblings can have significantly less than SCHED_POWER_SCALE |
9d5efe05 | 5527 | */ |
a6c75f2f | 5528 | if (!(sd->flags & SD_SHARE_CPUPOWER)) |
9d5efe05 SV |
5529 | return 0; |
5530 | ||
5531 | /* | |
5532 | * If ~90% of the cpu_power is still there, we're good. | |
5533 | */ | |
9c3f75cb | 5534 | if (group->sgp->power * 32 > group->sgp->power_orig * 29) |
9d5efe05 SV |
5535 | return 1; |
5536 | ||
5537 | return 0; | |
5538 | } | |
5539 | ||
30ce5dab PZ |
5540 | /* |
5541 | * Group imbalance indicates (and tries to solve) the problem where balancing | |
5542 | * groups is inadequate due to tsk_cpus_allowed() constraints. | |
5543 | * | |
5544 | * Imagine a situation of two groups of 4 cpus each and 4 tasks each with a | |
5545 | * cpumask covering 1 cpu of the first group and 3 cpus of the second group. | |
5546 | * Something like: | |
5547 | * | |
5548 | * { 0 1 2 3 } { 4 5 6 7 } | |
5549 | * * * * * | |
5550 | * | |
5551 | * If we were to balance group-wise we'd place two tasks in the first group and | |
5552 | * two tasks in the second group. Clearly this is undesired as it will overload | |
5553 | * cpu 3 and leave one of the cpus in the second group unused. | |
5554 | * | |
5555 | * The current solution to this issue is detecting the skew in the first group | |
6263322c PZ |
5556 | * by noticing the lower domain failed to reach balance and had difficulty |
5557 | * moving tasks due to affinity constraints. | |
30ce5dab PZ |
5558 | * |
5559 | * When this is so detected; this group becomes a candidate for busiest; see | |
ed1b7732 | 5560 | * update_sd_pick_busiest(). And calculate_imbalance() and |
6263322c | 5561 | * find_busiest_group() avoid some of the usual balance conditions to allow it |
30ce5dab PZ |
5562 | * to create an effective group imbalance. |
5563 | * | |
5564 | * This is a somewhat tricky proposition since the next run might not find the | |
5565 | * group imbalance and decide the groups need to be balanced again. A most | |
5566 | * subtle and fragile situation. | |
5567 | */ | |
5568 | ||
6263322c | 5569 | static inline int sg_imbalanced(struct sched_group *group) |
30ce5dab | 5570 | { |
6263322c | 5571 | return group->sgp->imbalance; |
30ce5dab PZ |
5572 | } |
5573 | ||
b37d9316 PZ |
5574 | /* |
5575 | * Compute the group capacity. | |
5576 | * | |
c61037e9 PZ |
5577 | * Avoid the issue where N*frac(smt_power) >= 1 creates 'phantom' cores by |
5578 | * first dividing out the smt factor and computing the actual number of cores | |
5579 | * and limit power unit capacity with that. | |
b37d9316 PZ |
5580 | */ |
5581 | static inline int sg_capacity(struct lb_env *env, struct sched_group *group) | |
5582 | { | |
c61037e9 PZ |
5583 | unsigned int capacity, smt, cpus; |
5584 | unsigned int power, power_orig; | |
5585 | ||
5586 | power = group->sgp->power; | |
5587 | power_orig = group->sgp->power_orig; | |
5588 | cpus = group->group_weight; | |
b37d9316 | 5589 | |
c61037e9 PZ |
5590 | /* smt := ceil(cpus / power), assumes: 1 < smt_power < 2 */ |
5591 | smt = DIV_ROUND_UP(SCHED_POWER_SCALE * cpus, power_orig); | |
5592 | capacity = cpus / smt; /* cores */ | |
b37d9316 | 5593 | |
c61037e9 | 5594 | capacity = min_t(unsigned, capacity, DIV_ROUND_CLOSEST(power, SCHED_POWER_SCALE)); |
b37d9316 PZ |
5595 | if (!capacity) |
5596 | capacity = fix_small_capacity(env->sd, group); | |
5597 | ||
5598 | return capacity; | |
5599 | } | |
5600 | ||
1e3c88bd PZ |
5601 | /** |
5602 | * update_sg_lb_stats - Update sched_group's statistics for load balancing. | |
cd96891d | 5603 | * @env: The load balancing environment. |
1e3c88bd | 5604 | * @group: sched_group whose statistics are to be updated. |
1e3c88bd | 5605 | * @load_idx: Load index of sched_domain of this_cpu for load calc. |
1e3c88bd | 5606 | * @local_group: Does group contain this_cpu. |
1e3c88bd PZ |
5607 | * @sgs: variable to hold the statistics for this group. |
5608 | */ | |
bd939f45 PZ |
5609 | static inline void update_sg_lb_stats(struct lb_env *env, |
5610 | struct sched_group *group, int load_idx, | |
23f0d209 | 5611 | int local_group, struct sg_lb_stats *sgs) |
1e3c88bd | 5612 | { |
30ce5dab | 5613 | unsigned long load; |
bd939f45 | 5614 | int i; |
1e3c88bd | 5615 | |
b72ff13c PZ |
5616 | memset(sgs, 0, sizeof(*sgs)); |
5617 | ||
b9403130 | 5618 | for_each_cpu_and(i, sched_group_cpus(group), env->cpus) { |
1e3c88bd PZ |
5619 | struct rq *rq = cpu_rq(i); |
5620 | ||
1e3c88bd | 5621 | /* Bias balancing toward cpus of our domain */ |
6263322c | 5622 | if (local_group) |
04f733b4 | 5623 | load = target_load(i, load_idx); |
6263322c | 5624 | else |
1e3c88bd | 5625 | load = source_load(i, load_idx); |
1e3c88bd PZ |
5626 | |
5627 | sgs->group_load += load; | |
380c9077 | 5628 | sgs->sum_nr_running += rq->nr_running; |
0ec8aa00 PZ |
5629 | #ifdef CONFIG_NUMA_BALANCING |
5630 | sgs->nr_numa_running += rq->nr_numa_running; | |
5631 | sgs->nr_preferred_running += rq->nr_preferred_running; | |
5632 | #endif | |
1e3c88bd | 5633 | sgs->sum_weighted_load += weighted_cpuload(i); |
aae6d3dd SS |
5634 | if (idle_cpu(i)) |
5635 | sgs->idle_cpus++; | |
1e3c88bd PZ |
5636 | } |
5637 | ||
1e3c88bd | 5638 | /* Adjust by relative CPU power of the group */ |
3ae11c90 PZ |
5639 | sgs->group_power = group->sgp->power; |
5640 | sgs->avg_load = (sgs->group_load*SCHED_POWER_SCALE) / sgs->group_power; | |
1e3c88bd | 5641 | |
dd5feea1 | 5642 | if (sgs->sum_nr_running) |
38d0f770 | 5643 | sgs->load_per_task = sgs->sum_weighted_load / sgs->sum_nr_running; |
1e3c88bd | 5644 | |
aae6d3dd | 5645 | sgs->group_weight = group->group_weight; |
fab47622 | 5646 | |
b37d9316 PZ |
5647 | sgs->group_imb = sg_imbalanced(group); |
5648 | sgs->group_capacity = sg_capacity(env, group); | |
5649 | ||
fab47622 NR |
5650 | if (sgs->group_capacity > sgs->sum_nr_running) |
5651 | sgs->group_has_capacity = 1; | |
1e3c88bd PZ |
5652 | } |
5653 | ||
532cb4c4 MN |
5654 | /** |
5655 | * update_sd_pick_busiest - return 1 on busiest group | |
cd96891d | 5656 | * @env: The load balancing environment. |
532cb4c4 MN |
5657 | * @sds: sched_domain statistics |
5658 | * @sg: sched_group candidate to be checked for being the busiest | |
b6b12294 | 5659 | * @sgs: sched_group statistics |
532cb4c4 MN |
5660 | * |
5661 | * Determine if @sg is a busier group than the previously selected | |
5662 | * busiest group. | |
e69f6186 YB |
5663 | * |
5664 | * Return: %true if @sg is a busier group than the previously selected | |
5665 | * busiest group. %false otherwise. | |
532cb4c4 | 5666 | */ |
bd939f45 | 5667 | static bool update_sd_pick_busiest(struct lb_env *env, |
532cb4c4 MN |
5668 | struct sd_lb_stats *sds, |
5669 | struct sched_group *sg, | |
bd939f45 | 5670 | struct sg_lb_stats *sgs) |
532cb4c4 | 5671 | { |
56cf515b | 5672 | if (sgs->avg_load <= sds->busiest_stat.avg_load) |
532cb4c4 MN |
5673 | return false; |
5674 | ||
5675 | if (sgs->sum_nr_running > sgs->group_capacity) | |
5676 | return true; | |
5677 | ||
5678 | if (sgs->group_imb) | |
5679 | return true; | |
5680 | ||
5681 | /* | |
5682 | * ASYM_PACKING needs to move all the work to the lowest | |
5683 | * numbered CPUs in the group, therefore mark all groups | |
5684 | * higher than ourself as busy. | |
5685 | */ | |
bd939f45 PZ |
5686 | if ((env->sd->flags & SD_ASYM_PACKING) && sgs->sum_nr_running && |
5687 | env->dst_cpu < group_first_cpu(sg)) { | |
532cb4c4 MN |
5688 | if (!sds->busiest) |
5689 | return true; | |
5690 | ||
5691 | if (group_first_cpu(sds->busiest) > group_first_cpu(sg)) | |
5692 | return true; | |
5693 | } | |
5694 | ||
5695 | return false; | |
5696 | } | |
5697 | ||
0ec8aa00 PZ |
5698 | #ifdef CONFIG_NUMA_BALANCING |
5699 | static inline enum fbq_type fbq_classify_group(struct sg_lb_stats *sgs) | |
5700 | { | |
5701 | if (sgs->sum_nr_running > sgs->nr_numa_running) | |
5702 | return regular; | |
5703 | if (sgs->sum_nr_running > sgs->nr_preferred_running) | |
5704 | return remote; | |
5705 | return all; | |
5706 | } | |
5707 | ||
5708 | static inline enum fbq_type fbq_classify_rq(struct rq *rq) | |
5709 | { | |
5710 | if (rq->nr_running > rq->nr_numa_running) | |
5711 | return regular; | |
5712 | if (rq->nr_running > rq->nr_preferred_running) | |
5713 | return remote; | |
5714 | return all; | |
5715 | } | |
5716 | #else | |
5717 | static inline enum fbq_type fbq_classify_group(struct sg_lb_stats *sgs) | |
5718 | { | |
5719 | return all; | |
5720 | } | |
5721 | ||
5722 | static inline enum fbq_type fbq_classify_rq(struct rq *rq) | |
5723 | { | |
5724 | return regular; | |
5725 | } | |
5726 | #endif /* CONFIG_NUMA_BALANCING */ | |
5727 | ||
1e3c88bd | 5728 | /** |
461819ac | 5729 | * update_sd_lb_stats - Update sched_domain's statistics for load balancing. |
cd96891d | 5730 | * @env: The load balancing environment. |
1e3c88bd PZ |
5731 | * @sds: variable to hold the statistics for this sched_domain. |
5732 | */ | |
0ec8aa00 | 5733 | static inline void update_sd_lb_stats(struct lb_env *env, struct sd_lb_stats *sds) |
1e3c88bd | 5734 | { |
bd939f45 PZ |
5735 | struct sched_domain *child = env->sd->child; |
5736 | struct sched_group *sg = env->sd->groups; | |
56cf515b | 5737 | struct sg_lb_stats tmp_sgs; |
1e3c88bd PZ |
5738 | int load_idx, prefer_sibling = 0; |
5739 | ||
5740 | if (child && child->flags & SD_PREFER_SIBLING) | |
5741 | prefer_sibling = 1; | |
5742 | ||
bd939f45 | 5743 | load_idx = get_sd_load_idx(env->sd, env->idle); |
1e3c88bd PZ |
5744 | |
5745 | do { | |
56cf515b | 5746 | struct sg_lb_stats *sgs = &tmp_sgs; |
1e3c88bd PZ |
5747 | int local_group; |
5748 | ||
bd939f45 | 5749 | local_group = cpumask_test_cpu(env->dst_cpu, sched_group_cpus(sg)); |
56cf515b JK |
5750 | if (local_group) { |
5751 | sds->local = sg; | |
5752 | sgs = &sds->local_stat; | |
b72ff13c PZ |
5753 | |
5754 | if (env->idle != CPU_NEWLY_IDLE || | |
5755 | time_after_eq(jiffies, sg->sgp->next_update)) | |
5756 | update_group_power(env->sd, env->dst_cpu); | |
56cf515b | 5757 | } |
1e3c88bd | 5758 | |
56cf515b | 5759 | update_sg_lb_stats(env, sg, load_idx, local_group, sgs); |
1e3c88bd | 5760 | |
b72ff13c PZ |
5761 | if (local_group) |
5762 | goto next_group; | |
5763 | ||
1e3c88bd PZ |
5764 | /* |
5765 | * In case the child domain prefers tasks go to siblings | |
532cb4c4 | 5766 | * first, lower the sg capacity to one so that we'll try |
75dd321d NR |
5767 | * and move all the excess tasks away. We lower the capacity |
5768 | * of a group only if the local group has the capacity to fit | |
5769 | * these excess tasks, i.e. nr_running < group_capacity. The | |
5770 | * extra check prevents the case where you always pull from the | |
5771 | * heaviest group when it is already under-utilized (possible | |
5772 | * with a large weight task outweighs the tasks on the system). | |
1e3c88bd | 5773 | */ |
b72ff13c PZ |
5774 | if (prefer_sibling && sds->local && |
5775 | sds->local_stat.group_has_capacity) | |
147c5fc2 | 5776 | sgs->group_capacity = min(sgs->group_capacity, 1U); |
1e3c88bd | 5777 | |
b72ff13c | 5778 | if (update_sd_pick_busiest(env, sds, sg, sgs)) { |
532cb4c4 | 5779 | sds->busiest = sg; |
56cf515b | 5780 | sds->busiest_stat = *sgs; |
1e3c88bd PZ |
5781 | } |
5782 | ||
b72ff13c PZ |
5783 | next_group: |
5784 | /* Now, start updating sd_lb_stats */ | |
5785 | sds->total_load += sgs->group_load; | |
5786 | sds->total_pwr += sgs->group_power; | |
5787 | ||
532cb4c4 | 5788 | sg = sg->next; |
bd939f45 | 5789 | } while (sg != env->sd->groups); |
0ec8aa00 PZ |
5790 | |
5791 | if (env->sd->flags & SD_NUMA) | |
5792 | env->fbq_type = fbq_classify_group(&sds->busiest_stat); | |
532cb4c4 MN |
5793 | } |
5794 | ||
532cb4c4 MN |
5795 | /** |
5796 | * check_asym_packing - Check to see if the group is packed into the | |
5797 | * sched doman. | |
5798 | * | |
5799 | * This is primarily intended to used at the sibling level. Some | |
5800 | * cores like POWER7 prefer to use lower numbered SMT threads. In the | |
5801 | * case of POWER7, it can move to lower SMT modes only when higher | |
5802 | * threads are idle. When in lower SMT modes, the threads will | |
5803 | * perform better since they share less core resources. Hence when we | |
5804 | * have idle threads, we want them to be the higher ones. | |
5805 | * | |
5806 | * This packing function is run on idle threads. It checks to see if | |
5807 | * the busiest CPU in this domain (core in the P7 case) has a higher | |
5808 | * CPU number than the packing function is being run on. Here we are | |
5809 | * assuming lower CPU number will be equivalent to lower a SMT thread | |
5810 | * number. | |
5811 | * | |
e69f6186 | 5812 | * Return: 1 when packing is required and a task should be moved to |
b6b12294 MN |
5813 | * this CPU. The amount of the imbalance is returned in *imbalance. |
5814 | * | |
cd96891d | 5815 | * @env: The load balancing environment. |
532cb4c4 | 5816 | * @sds: Statistics of the sched_domain which is to be packed |
532cb4c4 | 5817 | */ |
bd939f45 | 5818 | static int check_asym_packing(struct lb_env *env, struct sd_lb_stats *sds) |
532cb4c4 MN |
5819 | { |
5820 | int busiest_cpu; | |
5821 | ||
bd939f45 | 5822 | if (!(env->sd->flags & SD_ASYM_PACKING)) |
532cb4c4 MN |
5823 | return 0; |
5824 | ||
5825 | if (!sds->busiest) | |
5826 | return 0; | |
5827 | ||
5828 | busiest_cpu = group_first_cpu(sds->busiest); | |
bd939f45 | 5829 | if (env->dst_cpu > busiest_cpu) |
532cb4c4 MN |
5830 | return 0; |
5831 | ||
bd939f45 | 5832 | env->imbalance = DIV_ROUND_CLOSEST( |
3ae11c90 PZ |
5833 | sds->busiest_stat.avg_load * sds->busiest_stat.group_power, |
5834 | SCHED_POWER_SCALE); | |
bd939f45 | 5835 | |
532cb4c4 | 5836 | return 1; |
1e3c88bd PZ |
5837 | } |
5838 | ||
5839 | /** | |
5840 | * fix_small_imbalance - Calculate the minor imbalance that exists | |
5841 | * amongst the groups of a sched_domain, during | |
5842 | * load balancing. | |
cd96891d | 5843 | * @env: The load balancing environment. |
1e3c88bd | 5844 | * @sds: Statistics of the sched_domain whose imbalance is to be calculated. |
1e3c88bd | 5845 | */ |
bd939f45 PZ |
5846 | static inline |
5847 | void fix_small_imbalance(struct lb_env *env, struct sd_lb_stats *sds) | |
1e3c88bd PZ |
5848 | { |
5849 | unsigned long tmp, pwr_now = 0, pwr_move = 0; | |
5850 | unsigned int imbn = 2; | |
dd5feea1 | 5851 | unsigned long scaled_busy_load_per_task; |
56cf515b | 5852 | struct sg_lb_stats *local, *busiest; |
1e3c88bd | 5853 | |
56cf515b JK |
5854 | local = &sds->local_stat; |
5855 | busiest = &sds->busiest_stat; | |
1e3c88bd | 5856 | |
56cf515b JK |
5857 | if (!local->sum_nr_running) |
5858 | local->load_per_task = cpu_avg_load_per_task(env->dst_cpu); | |
5859 | else if (busiest->load_per_task > local->load_per_task) | |
5860 | imbn = 1; | |
dd5feea1 | 5861 | |
56cf515b JK |
5862 | scaled_busy_load_per_task = |
5863 | (busiest->load_per_task * SCHED_POWER_SCALE) / | |
3ae11c90 | 5864 | busiest->group_power; |
56cf515b | 5865 | |
3029ede3 VD |
5866 | if (busiest->avg_load + scaled_busy_load_per_task >= |
5867 | local->avg_load + (scaled_busy_load_per_task * imbn)) { | |
56cf515b | 5868 | env->imbalance = busiest->load_per_task; |
1e3c88bd PZ |
5869 | return; |
5870 | } | |
5871 | ||
5872 | /* | |
5873 | * OK, we don't have enough imbalance to justify moving tasks, | |
5874 | * however we may be able to increase total CPU power used by | |
5875 | * moving them. | |
5876 | */ | |
5877 | ||
3ae11c90 | 5878 | pwr_now += busiest->group_power * |
56cf515b | 5879 | min(busiest->load_per_task, busiest->avg_load); |
3ae11c90 | 5880 | pwr_now += local->group_power * |
56cf515b | 5881 | min(local->load_per_task, local->avg_load); |
1399fa78 | 5882 | pwr_now /= SCHED_POWER_SCALE; |
1e3c88bd PZ |
5883 | |
5884 | /* Amount of load we'd subtract */ | |
56cf515b | 5885 | tmp = (busiest->load_per_task * SCHED_POWER_SCALE) / |
3ae11c90 | 5886 | busiest->group_power; |
56cf515b | 5887 | if (busiest->avg_load > tmp) { |
3ae11c90 | 5888 | pwr_move += busiest->group_power * |
56cf515b JK |
5889 | min(busiest->load_per_task, |
5890 | busiest->avg_load - tmp); | |
5891 | } | |
1e3c88bd PZ |
5892 | |
5893 | /* Amount of load we'd add */ | |
3ae11c90 | 5894 | if (busiest->avg_load * busiest->group_power < |
56cf515b | 5895 | busiest->load_per_task * SCHED_POWER_SCALE) { |
3ae11c90 PZ |
5896 | tmp = (busiest->avg_load * busiest->group_power) / |
5897 | local->group_power; | |
56cf515b JK |
5898 | } else { |
5899 | tmp = (busiest->load_per_task * SCHED_POWER_SCALE) / | |
3ae11c90 | 5900 | local->group_power; |
56cf515b | 5901 | } |
3ae11c90 PZ |
5902 | pwr_move += local->group_power * |
5903 | min(local->load_per_task, local->avg_load + tmp); | |
1399fa78 | 5904 | pwr_move /= SCHED_POWER_SCALE; |
1e3c88bd PZ |
5905 | |
5906 | /* Move if we gain throughput */ | |
5907 | if (pwr_move > pwr_now) | |
56cf515b | 5908 | env->imbalance = busiest->load_per_task; |
1e3c88bd PZ |
5909 | } |
5910 | ||
5911 | /** | |
5912 | * calculate_imbalance - Calculate the amount of imbalance present within the | |
5913 | * groups of a given sched_domain during load balance. | |
bd939f45 | 5914 | * @env: load balance environment |
1e3c88bd | 5915 | * @sds: statistics of the sched_domain whose imbalance is to be calculated. |
1e3c88bd | 5916 | */ |
bd939f45 | 5917 | static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *sds) |
1e3c88bd | 5918 | { |
dd5feea1 | 5919 | unsigned long max_pull, load_above_capacity = ~0UL; |
56cf515b JK |
5920 | struct sg_lb_stats *local, *busiest; |
5921 | ||
5922 | local = &sds->local_stat; | |
56cf515b | 5923 | busiest = &sds->busiest_stat; |
dd5feea1 | 5924 | |
56cf515b | 5925 | if (busiest->group_imb) { |
30ce5dab PZ |
5926 | /* |
5927 | * In the group_imb case we cannot rely on group-wide averages | |
5928 | * to ensure cpu-load equilibrium, look at wider averages. XXX | |
5929 | */ | |
56cf515b JK |
5930 | busiest->load_per_task = |
5931 | min(busiest->load_per_task, sds->avg_load); | |
dd5feea1 SS |
5932 | } |
5933 | ||
1e3c88bd PZ |
5934 | /* |
5935 | * In the presence of smp nice balancing, certain scenarios can have | |
5936 | * max load less than avg load(as we skip the groups at or below | |
5937 | * its cpu_power, while calculating max_load..) | |
5938 | */ | |
b1885550 VD |
5939 | if (busiest->avg_load <= sds->avg_load || |
5940 | local->avg_load >= sds->avg_load) { | |
bd939f45 PZ |
5941 | env->imbalance = 0; |
5942 | return fix_small_imbalance(env, sds); | |
1e3c88bd PZ |
5943 | } |
5944 | ||
56cf515b | 5945 | if (!busiest->group_imb) { |
dd5feea1 SS |
5946 | /* |
5947 | * Don't want to pull so many tasks that a group would go idle. | |
30ce5dab PZ |
5948 | * Except of course for the group_imb case, since then we might |
5949 | * have to drop below capacity to reach cpu-load equilibrium. | |
dd5feea1 | 5950 | */ |
56cf515b JK |
5951 | load_above_capacity = |
5952 | (busiest->sum_nr_running - busiest->group_capacity); | |
dd5feea1 | 5953 | |
1399fa78 | 5954 | load_above_capacity *= (SCHED_LOAD_SCALE * SCHED_POWER_SCALE); |
3ae11c90 | 5955 | load_above_capacity /= busiest->group_power; |
dd5feea1 SS |
5956 | } |
5957 | ||
5958 | /* | |
5959 | * We're trying to get all the cpus to the average_load, so we don't | |
5960 | * want to push ourselves above the average load, nor do we wish to | |
5961 | * reduce the max loaded cpu below the average load. At the same time, | |
5962 | * we also don't want to reduce the group load below the group capacity | |
5963 | * (so that we can implement power-savings policies etc). Thus we look | |
5964 | * for the minimum possible imbalance. | |
dd5feea1 | 5965 | */ |
30ce5dab | 5966 | max_pull = min(busiest->avg_load - sds->avg_load, load_above_capacity); |
1e3c88bd PZ |
5967 | |
5968 | /* How much load to actually move to equalise the imbalance */ | |
56cf515b | 5969 | env->imbalance = min( |
3ae11c90 PZ |
5970 | max_pull * busiest->group_power, |
5971 | (sds->avg_load - local->avg_load) * local->group_power | |
56cf515b | 5972 | ) / SCHED_POWER_SCALE; |
1e3c88bd PZ |
5973 | |
5974 | /* | |
5975 | * if *imbalance is less than the average load per runnable task | |
25985edc | 5976 | * there is no guarantee that any tasks will be moved so we'll have |
1e3c88bd PZ |
5977 | * a think about bumping its value to force at least one task to be |
5978 | * moved | |
5979 | */ | |
56cf515b | 5980 | if (env->imbalance < busiest->load_per_task) |
bd939f45 | 5981 | return fix_small_imbalance(env, sds); |
1e3c88bd | 5982 | } |
fab47622 | 5983 | |
1e3c88bd PZ |
5984 | /******* find_busiest_group() helpers end here *********************/ |
5985 | ||
5986 | /** | |
5987 | * find_busiest_group - Returns the busiest group within the sched_domain | |
5988 | * if there is an imbalance. If there isn't an imbalance, and | |
5989 | * the user has opted for power-savings, it returns a group whose | |
5990 | * CPUs can be put to idle by rebalancing those tasks elsewhere, if | |
5991 | * such a group exists. | |
5992 | * | |
5993 | * Also calculates the amount of weighted load which should be moved | |
5994 | * to restore balance. | |
5995 | * | |
cd96891d | 5996 | * @env: The load balancing environment. |
1e3c88bd | 5997 | * |
e69f6186 | 5998 | * Return: - The busiest group if imbalance exists. |
1e3c88bd PZ |
5999 | * - If no imbalance and user has opted for power-savings balance, |
6000 | * return the least loaded group whose CPUs can be | |
6001 | * put to idle by rebalancing its tasks onto our group. | |
6002 | */ | |
56cf515b | 6003 | static struct sched_group *find_busiest_group(struct lb_env *env) |
1e3c88bd | 6004 | { |
56cf515b | 6005 | struct sg_lb_stats *local, *busiest; |
1e3c88bd PZ |
6006 | struct sd_lb_stats sds; |
6007 | ||
147c5fc2 | 6008 | init_sd_lb_stats(&sds); |
1e3c88bd PZ |
6009 | |
6010 | /* | |
6011 | * Compute the various statistics relavent for load balancing at | |
6012 | * this level. | |
6013 | */ | |
23f0d209 | 6014 | update_sd_lb_stats(env, &sds); |
56cf515b JK |
6015 | local = &sds.local_stat; |
6016 | busiest = &sds.busiest_stat; | |
1e3c88bd | 6017 | |
bd939f45 PZ |
6018 | if ((env->idle == CPU_IDLE || env->idle == CPU_NEWLY_IDLE) && |
6019 | check_asym_packing(env, &sds)) | |
532cb4c4 MN |
6020 | return sds.busiest; |
6021 | ||
cc57aa8f | 6022 | /* There is no busy sibling group to pull tasks from */ |
56cf515b | 6023 | if (!sds.busiest || busiest->sum_nr_running == 0) |
1e3c88bd PZ |
6024 | goto out_balanced; |
6025 | ||
1399fa78 | 6026 | sds.avg_load = (SCHED_POWER_SCALE * sds.total_load) / sds.total_pwr; |
b0432d8f | 6027 | |
866ab43e PZ |
6028 | /* |
6029 | * If the busiest group is imbalanced the below checks don't | |
30ce5dab | 6030 | * work because they assume all things are equal, which typically |
866ab43e PZ |
6031 | * isn't true due to cpus_allowed constraints and the like. |
6032 | */ | |
56cf515b | 6033 | if (busiest->group_imb) |
866ab43e PZ |
6034 | goto force_balance; |
6035 | ||
cc57aa8f | 6036 | /* SD_BALANCE_NEWIDLE trumps SMP nice when underutilized */ |
56cf515b JK |
6037 | if (env->idle == CPU_NEWLY_IDLE && local->group_has_capacity && |
6038 | !busiest->group_has_capacity) | |
fab47622 NR |
6039 | goto force_balance; |
6040 | ||
cc57aa8f PZ |
6041 | /* |
6042 | * If the local group is more busy than the selected busiest group | |
6043 | * don't try and pull any tasks. | |
6044 | */ | |
56cf515b | 6045 | if (local->avg_load >= busiest->avg_load) |
1e3c88bd PZ |
6046 | goto out_balanced; |
6047 | ||
cc57aa8f PZ |
6048 | /* |
6049 | * Don't pull any tasks if this group is already above the domain | |
6050 | * average load. | |
6051 | */ | |
56cf515b | 6052 | if (local->avg_load >= sds.avg_load) |
1e3c88bd PZ |
6053 | goto out_balanced; |
6054 | ||
bd939f45 | 6055 | if (env->idle == CPU_IDLE) { |
aae6d3dd SS |
6056 | /* |
6057 | * This cpu is idle. If the busiest group load doesn't | |
6058 | * have more tasks than the number of available cpu's and | |
6059 | * there is no imbalance between this and busiest group | |
6060 | * wrt to idle cpu's, it is balanced. | |
6061 | */ | |
56cf515b JK |
6062 | if ((local->idle_cpus < busiest->idle_cpus) && |
6063 | busiest->sum_nr_running <= busiest->group_weight) | |
aae6d3dd | 6064 | goto out_balanced; |
c186fafe PZ |
6065 | } else { |
6066 | /* | |
6067 | * In the CPU_NEWLY_IDLE, CPU_NOT_IDLE cases, use | |
6068 | * imbalance_pct to be conservative. | |
6069 | */ | |
56cf515b JK |
6070 | if (100 * busiest->avg_load <= |
6071 | env->sd->imbalance_pct * local->avg_load) | |
c186fafe | 6072 | goto out_balanced; |
aae6d3dd | 6073 | } |
1e3c88bd | 6074 | |
fab47622 | 6075 | force_balance: |
1e3c88bd | 6076 | /* Looks like there is an imbalance. Compute it */ |
bd939f45 | 6077 | calculate_imbalance(env, &sds); |
1e3c88bd PZ |
6078 | return sds.busiest; |
6079 | ||
6080 | out_balanced: | |
bd939f45 | 6081 | env->imbalance = 0; |
1e3c88bd PZ |
6082 | return NULL; |
6083 | } | |
6084 | ||
6085 | /* | |
6086 | * find_busiest_queue - find the busiest runqueue among the cpus in group. | |
6087 | */ | |
bd939f45 | 6088 | static struct rq *find_busiest_queue(struct lb_env *env, |
b9403130 | 6089 | struct sched_group *group) |
1e3c88bd PZ |
6090 | { |
6091 | struct rq *busiest = NULL, *rq; | |
95a79b80 | 6092 | unsigned long busiest_load = 0, busiest_power = 1; |
1e3c88bd PZ |
6093 | int i; |
6094 | ||
6906a408 | 6095 | for_each_cpu_and(i, sched_group_cpus(group), env->cpus) { |
0ec8aa00 PZ |
6096 | unsigned long power, capacity, wl; |
6097 | enum fbq_type rt; | |
6098 | ||
6099 | rq = cpu_rq(i); | |
6100 | rt = fbq_classify_rq(rq); | |
1e3c88bd | 6101 | |
0ec8aa00 PZ |
6102 | /* |
6103 | * We classify groups/runqueues into three groups: | |
6104 | * - regular: there are !numa tasks | |
6105 | * - remote: there are numa tasks that run on the 'wrong' node | |
6106 | * - all: there is no distinction | |
6107 | * | |
6108 | * In order to avoid migrating ideally placed numa tasks, | |
6109 | * ignore those when there's better options. | |
6110 | * | |
6111 | * If we ignore the actual busiest queue to migrate another | |
6112 | * task, the next balance pass can still reduce the busiest | |
6113 | * queue by moving tasks around inside the node. | |
6114 | * | |
6115 | * If we cannot move enough load due to this classification | |
6116 | * the next pass will adjust the group classification and | |
6117 | * allow migration of more tasks. | |
6118 | * | |
6119 | * Both cases only affect the total convergence complexity. | |
6120 | */ | |
6121 | if (rt > env->fbq_type) | |
6122 | continue; | |
6123 | ||
6124 | power = power_of(i); | |
6125 | capacity = DIV_ROUND_CLOSEST(power, SCHED_POWER_SCALE); | |
9d5efe05 | 6126 | if (!capacity) |
bd939f45 | 6127 | capacity = fix_small_capacity(env->sd, group); |
9d5efe05 | 6128 | |
6e40f5bb | 6129 | wl = weighted_cpuload(i); |
1e3c88bd | 6130 | |
6e40f5bb TG |
6131 | /* |
6132 | * When comparing with imbalance, use weighted_cpuload() | |
6133 | * which is not scaled with the cpu power. | |
6134 | */ | |
bd939f45 | 6135 | if (capacity && rq->nr_running == 1 && wl > env->imbalance) |
1e3c88bd PZ |
6136 | continue; |
6137 | ||
6e40f5bb TG |
6138 | /* |
6139 | * For the load comparisons with the other cpu's, consider | |
6140 | * the weighted_cpuload() scaled with the cpu power, so that | |
6141 | * the load can be moved away from the cpu that is potentially | |
6142 | * running at a lower capacity. | |
95a79b80 JK |
6143 | * |
6144 | * Thus we're looking for max(wl_i / power_i), crosswise | |
6145 | * multiplication to rid ourselves of the division works out | |
6146 | * to: wl_i * power_j > wl_j * power_i; where j is our | |
6147 | * previous maximum. | |
6e40f5bb | 6148 | */ |
95a79b80 JK |
6149 | if (wl * busiest_power > busiest_load * power) { |
6150 | busiest_load = wl; | |
6151 | busiest_power = power; | |
1e3c88bd PZ |
6152 | busiest = rq; |
6153 | } | |
6154 | } | |
6155 | ||
6156 | return busiest; | |
6157 | } | |
6158 | ||
6159 | /* | |
6160 | * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but | |
6161 | * so long as it is large enough. | |
6162 | */ | |
6163 | #define MAX_PINNED_INTERVAL 512 | |
6164 | ||
6165 | /* Working cpumask for load_balance and load_balance_newidle. */ | |
e6252c3e | 6166 | DEFINE_PER_CPU(cpumask_var_t, load_balance_mask); |
1e3c88bd | 6167 | |
bd939f45 | 6168 | static int need_active_balance(struct lb_env *env) |
1af3ed3d | 6169 | { |
bd939f45 PZ |
6170 | struct sched_domain *sd = env->sd; |
6171 | ||
6172 | if (env->idle == CPU_NEWLY_IDLE) { | |
532cb4c4 MN |
6173 | |
6174 | /* | |
6175 | * ASYM_PACKING needs to force migrate tasks from busy but | |
6176 | * higher numbered CPUs in order to pack all tasks in the | |
6177 | * lowest numbered CPUs. | |
6178 | */ | |
bd939f45 | 6179 | if ((sd->flags & SD_ASYM_PACKING) && env->src_cpu > env->dst_cpu) |
532cb4c4 | 6180 | return 1; |
1af3ed3d PZ |
6181 | } |
6182 | ||
6183 | return unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2); | |
6184 | } | |
6185 | ||
969c7921 TH |
6186 | static int active_load_balance_cpu_stop(void *data); |
6187 | ||
23f0d209 JK |
6188 | static int should_we_balance(struct lb_env *env) |
6189 | { | |
6190 | struct sched_group *sg = env->sd->groups; | |
6191 | struct cpumask *sg_cpus, *sg_mask; | |
6192 | int cpu, balance_cpu = -1; | |
6193 | ||
6194 | /* | |
6195 | * In the newly idle case, we will allow all the cpu's | |
6196 | * to do the newly idle load balance. | |
6197 | */ | |
6198 | if (env->idle == CPU_NEWLY_IDLE) | |
6199 | return 1; | |
6200 | ||
6201 | sg_cpus = sched_group_cpus(sg); | |
6202 | sg_mask = sched_group_mask(sg); | |
6203 | /* Try to find first idle cpu */ | |
6204 | for_each_cpu_and(cpu, sg_cpus, env->cpus) { | |
6205 | if (!cpumask_test_cpu(cpu, sg_mask) || !idle_cpu(cpu)) | |
6206 | continue; | |
6207 | ||
6208 | balance_cpu = cpu; | |
6209 | break; | |
6210 | } | |
6211 | ||
6212 | if (balance_cpu == -1) | |
6213 | balance_cpu = group_balance_cpu(sg); | |
6214 | ||
6215 | /* | |
6216 | * First idle cpu or the first cpu(busiest) in this sched group | |
6217 | * is eligible for doing load balancing at this and above domains. | |
6218 | */ | |
b0cff9d8 | 6219 | return balance_cpu == env->dst_cpu; |
23f0d209 JK |
6220 | } |
6221 | ||
1e3c88bd PZ |
6222 | /* |
6223 | * Check this_cpu to ensure it is balanced within domain. Attempt to move | |
6224 | * tasks if there is an imbalance. | |
6225 | */ | |
6226 | static int load_balance(int this_cpu, struct rq *this_rq, | |
6227 | struct sched_domain *sd, enum cpu_idle_type idle, | |
23f0d209 | 6228 | int *continue_balancing) |
1e3c88bd | 6229 | { |
88b8dac0 | 6230 | int ld_moved, cur_ld_moved, active_balance = 0; |
6263322c | 6231 | struct sched_domain *sd_parent = sd->parent; |
1e3c88bd | 6232 | struct sched_group *group; |
1e3c88bd PZ |
6233 | struct rq *busiest; |
6234 | unsigned long flags; | |
e6252c3e | 6235 | struct cpumask *cpus = __get_cpu_var(load_balance_mask); |
1e3c88bd | 6236 | |
8e45cb54 PZ |
6237 | struct lb_env env = { |
6238 | .sd = sd, | |
ddcdf6e7 PZ |
6239 | .dst_cpu = this_cpu, |
6240 | .dst_rq = this_rq, | |
88b8dac0 | 6241 | .dst_grpmask = sched_group_cpus(sd->groups), |
8e45cb54 | 6242 | .idle = idle, |
eb95308e | 6243 | .loop_break = sched_nr_migrate_break, |
b9403130 | 6244 | .cpus = cpus, |
0ec8aa00 | 6245 | .fbq_type = all, |
8e45cb54 PZ |
6246 | }; |
6247 | ||
cfc03118 JK |
6248 | /* |
6249 | * For NEWLY_IDLE load_balancing, we don't need to consider | |
6250 | * other cpus in our group | |
6251 | */ | |
e02e60c1 | 6252 | if (idle == CPU_NEWLY_IDLE) |
cfc03118 | 6253 | env.dst_grpmask = NULL; |
cfc03118 | 6254 | |
1e3c88bd PZ |
6255 | cpumask_copy(cpus, cpu_active_mask); |
6256 | ||
1e3c88bd PZ |
6257 | schedstat_inc(sd, lb_count[idle]); |
6258 | ||
6259 | redo: | |
23f0d209 JK |
6260 | if (!should_we_balance(&env)) { |
6261 | *continue_balancing = 0; | |
1e3c88bd | 6262 | goto out_balanced; |
23f0d209 | 6263 | } |
1e3c88bd | 6264 | |
23f0d209 | 6265 | group = find_busiest_group(&env); |
1e3c88bd PZ |
6266 | if (!group) { |
6267 | schedstat_inc(sd, lb_nobusyg[idle]); | |
6268 | goto out_balanced; | |
6269 | } | |
6270 | ||
b9403130 | 6271 | busiest = find_busiest_queue(&env, group); |
1e3c88bd PZ |
6272 | if (!busiest) { |
6273 | schedstat_inc(sd, lb_nobusyq[idle]); | |
6274 | goto out_balanced; | |
6275 | } | |
6276 | ||
78feefc5 | 6277 | BUG_ON(busiest == env.dst_rq); |
1e3c88bd | 6278 | |
bd939f45 | 6279 | schedstat_add(sd, lb_imbalance[idle], env.imbalance); |
1e3c88bd PZ |
6280 | |
6281 | ld_moved = 0; | |
6282 | if (busiest->nr_running > 1) { | |
6283 | /* | |
6284 | * Attempt to move tasks. If find_busiest_group has found | |
6285 | * an imbalance but busiest->nr_running <= 1, the group is | |
6286 | * still unbalanced. ld_moved simply stays zero, so it is | |
6287 | * correctly treated as an imbalance. | |
6288 | */ | |
8e45cb54 | 6289 | env.flags |= LBF_ALL_PINNED; |
c82513e5 PZ |
6290 | env.src_cpu = busiest->cpu; |
6291 | env.src_rq = busiest; | |
6292 | env.loop_max = min(sysctl_sched_nr_migrate, busiest->nr_running); | |
8e45cb54 | 6293 | |
5d6523eb | 6294 | more_balance: |
1e3c88bd | 6295 | local_irq_save(flags); |
78feefc5 | 6296 | double_rq_lock(env.dst_rq, busiest); |
88b8dac0 SV |
6297 | |
6298 | /* | |
6299 | * cur_ld_moved - load moved in current iteration | |
6300 | * ld_moved - cumulative load moved across iterations | |
6301 | */ | |
6302 | cur_ld_moved = move_tasks(&env); | |
6303 | ld_moved += cur_ld_moved; | |
78feefc5 | 6304 | double_rq_unlock(env.dst_rq, busiest); |
1e3c88bd PZ |
6305 | local_irq_restore(flags); |
6306 | ||
6307 | /* | |
6308 | * some other cpu did the load balance for us. | |
6309 | */ | |
88b8dac0 SV |
6310 | if (cur_ld_moved && env.dst_cpu != smp_processor_id()) |
6311 | resched_cpu(env.dst_cpu); | |
6312 | ||
f1cd0858 JK |
6313 | if (env.flags & LBF_NEED_BREAK) { |
6314 | env.flags &= ~LBF_NEED_BREAK; | |
6315 | goto more_balance; | |
6316 | } | |
6317 | ||
88b8dac0 SV |
6318 | /* |
6319 | * Revisit (affine) tasks on src_cpu that couldn't be moved to | |
6320 | * us and move them to an alternate dst_cpu in our sched_group | |
6321 | * where they can run. The upper limit on how many times we | |
6322 | * iterate on same src_cpu is dependent on number of cpus in our | |
6323 | * sched_group. | |
6324 | * | |
6325 | * This changes load balance semantics a bit on who can move | |
6326 | * load to a given_cpu. In addition to the given_cpu itself | |
6327 | * (or a ilb_cpu acting on its behalf where given_cpu is | |
6328 | * nohz-idle), we now have balance_cpu in a position to move | |
6329 | * load to given_cpu. In rare situations, this may cause | |
6330 | * conflicts (balance_cpu and given_cpu/ilb_cpu deciding | |
6331 | * _independently_ and at _same_ time to move some load to | |
6332 | * given_cpu) causing exceess load to be moved to given_cpu. | |
6333 | * This however should not happen so much in practice and | |
6334 | * moreover subsequent load balance cycles should correct the | |
6335 | * excess load moved. | |
6336 | */ | |
6263322c | 6337 | if ((env.flags & LBF_DST_PINNED) && env.imbalance > 0) { |
88b8dac0 | 6338 | |
7aff2e3a VD |
6339 | /* Prevent to re-select dst_cpu via env's cpus */ |
6340 | cpumask_clear_cpu(env.dst_cpu, env.cpus); | |
6341 | ||
78feefc5 | 6342 | env.dst_rq = cpu_rq(env.new_dst_cpu); |
88b8dac0 | 6343 | env.dst_cpu = env.new_dst_cpu; |
6263322c | 6344 | env.flags &= ~LBF_DST_PINNED; |
88b8dac0 SV |
6345 | env.loop = 0; |
6346 | env.loop_break = sched_nr_migrate_break; | |
e02e60c1 | 6347 | |
88b8dac0 SV |
6348 | /* |
6349 | * Go back to "more_balance" rather than "redo" since we | |
6350 | * need to continue with same src_cpu. | |
6351 | */ | |
6352 | goto more_balance; | |
6353 | } | |
1e3c88bd | 6354 | |
6263322c PZ |
6355 | /* |
6356 | * We failed to reach balance because of affinity. | |
6357 | */ | |
6358 | if (sd_parent) { | |
6359 | int *group_imbalance = &sd_parent->groups->sgp->imbalance; | |
6360 | ||
6361 | if ((env.flags & LBF_SOME_PINNED) && env.imbalance > 0) { | |
6362 | *group_imbalance = 1; | |
6363 | } else if (*group_imbalance) | |
6364 | *group_imbalance = 0; | |
6365 | } | |
6366 | ||
1e3c88bd | 6367 | /* All tasks on this runqueue were pinned by CPU affinity */ |
8e45cb54 | 6368 | if (unlikely(env.flags & LBF_ALL_PINNED)) { |
1e3c88bd | 6369 | cpumask_clear_cpu(cpu_of(busiest), cpus); |
bbf18b19 PN |
6370 | if (!cpumask_empty(cpus)) { |
6371 | env.loop = 0; | |
6372 | env.loop_break = sched_nr_migrate_break; | |
1e3c88bd | 6373 | goto redo; |
bbf18b19 | 6374 | } |
1e3c88bd PZ |
6375 | goto out_balanced; |
6376 | } | |
6377 | } | |
6378 | ||
6379 | if (!ld_moved) { | |
6380 | schedstat_inc(sd, lb_failed[idle]); | |
58b26c4c VP |
6381 | /* |
6382 | * Increment the failure counter only on periodic balance. | |
6383 | * We do not want newidle balance, which can be very | |
6384 | * frequent, pollute the failure counter causing | |
6385 | * excessive cache_hot migrations and active balances. | |
6386 | */ | |
6387 | if (idle != CPU_NEWLY_IDLE) | |
6388 | sd->nr_balance_failed++; | |
1e3c88bd | 6389 | |
bd939f45 | 6390 | if (need_active_balance(&env)) { |
1e3c88bd PZ |
6391 | raw_spin_lock_irqsave(&busiest->lock, flags); |
6392 | ||
969c7921 TH |
6393 | /* don't kick the active_load_balance_cpu_stop, |
6394 | * if the curr task on busiest cpu can't be | |
6395 | * moved to this_cpu | |
1e3c88bd PZ |
6396 | */ |
6397 | if (!cpumask_test_cpu(this_cpu, | |
fa17b507 | 6398 | tsk_cpus_allowed(busiest->curr))) { |
1e3c88bd PZ |
6399 | raw_spin_unlock_irqrestore(&busiest->lock, |
6400 | flags); | |
8e45cb54 | 6401 | env.flags |= LBF_ALL_PINNED; |
1e3c88bd PZ |
6402 | goto out_one_pinned; |
6403 | } | |
6404 | ||
969c7921 TH |
6405 | /* |
6406 | * ->active_balance synchronizes accesses to | |
6407 | * ->active_balance_work. Once set, it's cleared | |
6408 | * only after active load balance is finished. | |
6409 | */ | |
1e3c88bd PZ |
6410 | if (!busiest->active_balance) { |
6411 | busiest->active_balance = 1; | |
6412 | busiest->push_cpu = this_cpu; | |
6413 | active_balance = 1; | |
6414 | } | |
6415 | raw_spin_unlock_irqrestore(&busiest->lock, flags); | |
969c7921 | 6416 | |
bd939f45 | 6417 | if (active_balance) { |
969c7921 TH |
6418 | stop_one_cpu_nowait(cpu_of(busiest), |
6419 | active_load_balance_cpu_stop, busiest, | |
6420 | &busiest->active_balance_work); | |
bd939f45 | 6421 | } |
1e3c88bd PZ |
6422 | |
6423 | /* | |
6424 | * We've kicked active balancing, reset the failure | |
6425 | * counter. | |
6426 | */ | |
6427 | sd->nr_balance_failed = sd->cache_nice_tries+1; | |
6428 | } | |
6429 | } else | |
6430 | sd->nr_balance_failed = 0; | |
6431 | ||
6432 | if (likely(!active_balance)) { | |
6433 | /* We were unbalanced, so reset the balancing interval */ | |
6434 | sd->balance_interval = sd->min_interval; | |
6435 | } else { | |
6436 | /* | |
6437 | * If we've begun active balancing, start to back off. This | |
6438 | * case may not be covered by the all_pinned logic if there | |
6439 | * is only 1 task on the busy runqueue (because we don't call | |
6440 | * move_tasks). | |
6441 | */ | |
6442 | if (sd->balance_interval < sd->max_interval) | |
6443 | sd->balance_interval *= 2; | |
6444 | } | |
6445 | ||
1e3c88bd PZ |
6446 | goto out; |
6447 | ||
6448 | out_balanced: | |
6449 | schedstat_inc(sd, lb_balanced[idle]); | |
6450 | ||
6451 | sd->nr_balance_failed = 0; | |
6452 | ||
6453 | out_one_pinned: | |
6454 | /* tune up the balancing interval */ | |
8e45cb54 | 6455 | if (((env.flags & LBF_ALL_PINNED) && |
5b54b56b | 6456 | sd->balance_interval < MAX_PINNED_INTERVAL) || |
1e3c88bd PZ |
6457 | (sd->balance_interval < sd->max_interval)) |
6458 | sd->balance_interval *= 2; | |
6459 | ||
46e49b38 | 6460 | ld_moved = 0; |
1e3c88bd | 6461 | out: |
1e3c88bd PZ |
6462 | return ld_moved; |
6463 | } | |
6464 | ||
1e3c88bd PZ |
6465 | /* |
6466 | * idle_balance is called by schedule() if this_cpu is about to become | |
6467 | * idle. Attempts to pull tasks from other CPUs. | |
6468 | */ | |
029632fb | 6469 | void idle_balance(int this_cpu, struct rq *this_rq) |
1e3c88bd PZ |
6470 | { |
6471 | struct sched_domain *sd; | |
6472 | int pulled_task = 0; | |
6473 | unsigned long next_balance = jiffies + HZ; | |
9bd721c5 | 6474 | u64 curr_cost = 0; |
1e3c88bd | 6475 | |
78becc27 | 6476 | this_rq->idle_stamp = rq_clock(this_rq); |
1e3c88bd PZ |
6477 | |
6478 | if (this_rq->avg_idle < sysctl_sched_migration_cost) | |
6479 | return; | |
6480 | ||
f492e12e PZ |
6481 | /* |
6482 | * Drop the rq->lock, but keep IRQ/preempt disabled. | |
6483 | */ | |
6484 | raw_spin_unlock(&this_rq->lock); | |
6485 | ||
48a16753 | 6486 | update_blocked_averages(this_cpu); |
dce840a0 | 6487 | rcu_read_lock(); |
1e3c88bd PZ |
6488 | for_each_domain(this_cpu, sd) { |
6489 | unsigned long interval; | |
23f0d209 | 6490 | int continue_balancing = 1; |
9bd721c5 | 6491 | u64 t0, domain_cost; |
1e3c88bd PZ |
6492 | |
6493 | if (!(sd->flags & SD_LOAD_BALANCE)) | |
6494 | continue; | |
6495 | ||
9bd721c5 JL |
6496 | if (this_rq->avg_idle < curr_cost + sd->max_newidle_lb_cost) |
6497 | break; | |
6498 | ||
f492e12e | 6499 | if (sd->flags & SD_BALANCE_NEWIDLE) { |
9bd721c5 JL |
6500 | t0 = sched_clock_cpu(this_cpu); |
6501 | ||
1e3c88bd | 6502 | /* If we've pulled tasks over stop searching: */ |
f492e12e | 6503 | pulled_task = load_balance(this_cpu, this_rq, |
23f0d209 JK |
6504 | sd, CPU_NEWLY_IDLE, |
6505 | &continue_balancing); | |
9bd721c5 JL |
6506 | |
6507 | domain_cost = sched_clock_cpu(this_cpu) - t0; | |
6508 | if (domain_cost > sd->max_newidle_lb_cost) | |
6509 | sd->max_newidle_lb_cost = domain_cost; | |
6510 | ||
6511 | curr_cost += domain_cost; | |
f492e12e | 6512 | } |
1e3c88bd PZ |
6513 | |
6514 | interval = msecs_to_jiffies(sd->balance_interval); | |
6515 | if (time_after(next_balance, sd->last_balance + interval)) | |
6516 | next_balance = sd->last_balance + interval; | |
d5ad140b NR |
6517 | if (pulled_task) { |
6518 | this_rq->idle_stamp = 0; | |
1e3c88bd | 6519 | break; |
d5ad140b | 6520 | } |
1e3c88bd | 6521 | } |
dce840a0 | 6522 | rcu_read_unlock(); |
f492e12e PZ |
6523 | |
6524 | raw_spin_lock(&this_rq->lock); | |
6525 | ||
1e3c88bd PZ |
6526 | if (pulled_task || time_after(jiffies, this_rq->next_balance)) { |
6527 | /* | |
6528 | * We are going idle. next_balance may be set based on | |
6529 | * a busy processor. So reset next_balance. | |
6530 | */ | |
6531 | this_rq->next_balance = next_balance; | |
6532 | } | |
9bd721c5 JL |
6533 | |
6534 | if (curr_cost > this_rq->max_idle_balance_cost) | |
6535 | this_rq->max_idle_balance_cost = curr_cost; | |
1e3c88bd PZ |
6536 | } |
6537 | ||
6538 | /* | |
969c7921 TH |
6539 | * active_load_balance_cpu_stop is run by cpu stopper. It pushes |
6540 | * running tasks off the busiest CPU onto idle CPUs. It requires at | |
6541 | * least 1 task to be running on each physical CPU where possible, and | |
6542 | * avoids physical / logical imbalances. | |
1e3c88bd | 6543 | */ |
969c7921 | 6544 | static int active_load_balance_cpu_stop(void *data) |
1e3c88bd | 6545 | { |
969c7921 TH |
6546 | struct rq *busiest_rq = data; |
6547 | int busiest_cpu = cpu_of(busiest_rq); | |
1e3c88bd | 6548 | int target_cpu = busiest_rq->push_cpu; |
969c7921 | 6549 | struct rq *target_rq = cpu_rq(target_cpu); |
1e3c88bd | 6550 | struct sched_domain *sd; |
969c7921 TH |
6551 | |
6552 | raw_spin_lock_irq(&busiest_rq->lock); | |
6553 | ||
6554 | /* make sure the requested cpu hasn't gone down in the meantime */ | |
6555 | if (unlikely(busiest_cpu != smp_processor_id() || | |
6556 | !busiest_rq->active_balance)) | |
6557 | goto out_unlock; | |
1e3c88bd PZ |
6558 | |
6559 | /* Is there any task to move? */ | |
6560 | if (busiest_rq->nr_running <= 1) | |
969c7921 | 6561 | goto out_unlock; |
1e3c88bd PZ |
6562 | |
6563 | /* | |
6564 | * This condition is "impossible", if it occurs | |
6565 | * we need to fix it. Originally reported by | |
6566 | * Bjorn Helgaas on a 128-cpu setup. | |
6567 | */ | |
6568 | BUG_ON(busiest_rq == target_rq); | |
6569 | ||
6570 | /* move a task from busiest_rq to target_rq */ | |
6571 | double_lock_balance(busiest_rq, target_rq); | |
1e3c88bd PZ |
6572 | |
6573 | /* Search for an sd spanning us and the target CPU. */ | |
dce840a0 | 6574 | rcu_read_lock(); |
1e3c88bd PZ |
6575 | for_each_domain(target_cpu, sd) { |
6576 | if ((sd->flags & SD_LOAD_BALANCE) && | |
6577 | cpumask_test_cpu(busiest_cpu, sched_domain_span(sd))) | |
6578 | break; | |
6579 | } | |
6580 | ||
6581 | if (likely(sd)) { | |
8e45cb54 PZ |
6582 | struct lb_env env = { |
6583 | .sd = sd, | |
ddcdf6e7 PZ |
6584 | .dst_cpu = target_cpu, |
6585 | .dst_rq = target_rq, | |
6586 | .src_cpu = busiest_rq->cpu, | |
6587 | .src_rq = busiest_rq, | |
8e45cb54 PZ |
6588 | .idle = CPU_IDLE, |
6589 | }; | |
6590 | ||
1e3c88bd PZ |
6591 | schedstat_inc(sd, alb_count); |
6592 | ||
8e45cb54 | 6593 | if (move_one_task(&env)) |
1e3c88bd PZ |
6594 | schedstat_inc(sd, alb_pushed); |
6595 | else | |
6596 | schedstat_inc(sd, alb_failed); | |
6597 | } | |
dce840a0 | 6598 | rcu_read_unlock(); |
1e3c88bd | 6599 | double_unlock_balance(busiest_rq, target_rq); |
969c7921 TH |
6600 | out_unlock: |
6601 | busiest_rq->active_balance = 0; | |
6602 | raw_spin_unlock_irq(&busiest_rq->lock); | |
6603 | return 0; | |
1e3c88bd PZ |
6604 | } |
6605 | ||
3451d024 | 6606 | #ifdef CONFIG_NO_HZ_COMMON |
83cd4fe2 VP |
6607 | /* |
6608 | * idle load balancing details | |
83cd4fe2 VP |
6609 | * - When one of the busy CPUs notice that there may be an idle rebalancing |
6610 | * needed, they will kick the idle load balancer, which then does idle | |
6611 | * load balancing for all the idle CPUs. | |
6612 | */ | |
1e3c88bd | 6613 | static struct { |
83cd4fe2 | 6614 | cpumask_var_t idle_cpus_mask; |
0b005cf5 | 6615 | atomic_t nr_cpus; |
83cd4fe2 VP |
6616 | unsigned long next_balance; /* in jiffy units */ |
6617 | } nohz ____cacheline_aligned; | |
1e3c88bd | 6618 | |
3dd0337d | 6619 | static inline int find_new_ilb(void) |
1e3c88bd | 6620 | { |
0b005cf5 | 6621 | int ilb = cpumask_first(nohz.idle_cpus_mask); |
1e3c88bd | 6622 | |
786d6dc7 SS |
6623 | if (ilb < nr_cpu_ids && idle_cpu(ilb)) |
6624 | return ilb; | |
6625 | ||
6626 | return nr_cpu_ids; | |
1e3c88bd | 6627 | } |
1e3c88bd | 6628 | |
83cd4fe2 VP |
6629 | /* |
6630 | * Kick a CPU to do the nohz balancing, if it is time for it. We pick the | |
6631 | * nohz_load_balancer CPU (if there is one) otherwise fallback to any idle | |
6632 | * CPU (if there is one). | |
6633 | */ | |
0aeeeeba | 6634 | static void nohz_balancer_kick(void) |
83cd4fe2 VP |
6635 | { |
6636 | int ilb_cpu; | |
6637 | ||
6638 | nohz.next_balance++; | |
6639 | ||
3dd0337d | 6640 | ilb_cpu = find_new_ilb(); |
83cd4fe2 | 6641 | |
0b005cf5 SS |
6642 | if (ilb_cpu >= nr_cpu_ids) |
6643 | return; | |
83cd4fe2 | 6644 | |
cd490c5b | 6645 | if (test_and_set_bit(NOHZ_BALANCE_KICK, nohz_flags(ilb_cpu))) |
1c792db7 SS |
6646 | return; |
6647 | /* | |
6648 | * Use smp_send_reschedule() instead of resched_cpu(). | |
6649 | * This way we generate a sched IPI on the target cpu which | |
6650 | * is idle. And the softirq performing nohz idle load balance | |
6651 | * will be run before returning from the IPI. | |
6652 | */ | |
6653 | smp_send_reschedule(ilb_cpu); | |
83cd4fe2 VP |
6654 | return; |
6655 | } | |
6656 | ||
c1cc017c | 6657 | static inline void nohz_balance_exit_idle(int cpu) |
71325960 SS |
6658 | { |
6659 | if (unlikely(test_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu)))) { | |
6660 | cpumask_clear_cpu(cpu, nohz.idle_cpus_mask); | |
6661 | atomic_dec(&nohz.nr_cpus); | |
6662 | clear_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu)); | |
6663 | } | |
6664 | } | |
6665 | ||
69e1e811 SS |
6666 | static inline void set_cpu_sd_state_busy(void) |
6667 | { | |
6668 | struct sched_domain *sd; | |
37dc6b50 | 6669 | int cpu = smp_processor_id(); |
69e1e811 | 6670 | |
69e1e811 | 6671 | rcu_read_lock(); |
37dc6b50 | 6672 | sd = rcu_dereference(per_cpu(sd_busy, cpu)); |
25f55d9d VG |
6673 | |
6674 | if (!sd || !sd->nohz_idle) | |
6675 | goto unlock; | |
6676 | sd->nohz_idle = 0; | |
6677 | ||
37dc6b50 | 6678 | atomic_inc(&sd->groups->sgp->nr_busy_cpus); |
25f55d9d | 6679 | unlock: |
69e1e811 SS |
6680 | rcu_read_unlock(); |
6681 | } | |
6682 | ||
6683 | void set_cpu_sd_state_idle(void) | |
6684 | { | |
6685 | struct sched_domain *sd; | |
37dc6b50 | 6686 | int cpu = smp_processor_id(); |
69e1e811 | 6687 | |
69e1e811 | 6688 | rcu_read_lock(); |
37dc6b50 | 6689 | sd = rcu_dereference(per_cpu(sd_busy, cpu)); |
25f55d9d VG |
6690 | |
6691 | if (!sd || sd->nohz_idle) | |
6692 | goto unlock; | |
6693 | sd->nohz_idle = 1; | |
6694 | ||
37dc6b50 | 6695 | atomic_dec(&sd->groups->sgp->nr_busy_cpus); |
25f55d9d | 6696 | unlock: |
69e1e811 SS |
6697 | rcu_read_unlock(); |
6698 | } | |
6699 | ||
1e3c88bd | 6700 | /* |
c1cc017c | 6701 | * This routine will record that the cpu is going idle with tick stopped. |
0b005cf5 | 6702 | * This info will be used in performing idle load balancing in the future. |
1e3c88bd | 6703 | */ |
c1cc017c | 6704 | void nohz_balance_enter_idle(int cpu) |
1e3c88bd | 6705 | { |
71325960 SS |
6706 | /* |
6707 | * If this cpu is going down, then nothing needs to be done. | |
6708 | */ | |
6709 | if (!cpu_active(cpu)) | |
6710 | return; | |
6711 | ||
c1cc017c AS |
6712 | if (test_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu))) |
6713 | return; | |
1e3c88bd | 6714 | |
c1cc017c AS |
6715 | cpumask_set_cpu(cpu, nohz.idle_cpus_mask); |
6716 | atomic_inc(&nohz.nr_cpus); | |
6717 | set_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu)); | |
1e3c88bd | 6718 | } |
71325960 | 6719 | |
0db0628d | 6720 | static int sched_ilb_notifier(struct notifier_block *nfb, |
71325960 SS |
6721 | unsigned long action, void *hcpu) |
6722 | { | |
6723 | switch (action & ~CPU_TASKS_FROZEN) { | |
6724 | case CPU_DYING: | |
c1cc017c | 6725 | nohz_balance_exit_idle(smp_processor_id()); |
71325960 SS |
6726 | return NOTIFY_OK; |
6727 | default: | |
6728 | return NOTIFY_DONE; | |
6729 | } | |
6730 | } | |
1e3c88bd PZ |
6731 | #endif |
6732 | ||
6733 | static DEFINE_SPINLOCK(balancing); | |
6734 | ||
49c022e6 PZ |
6735 | /* |
6736 | * Scale the max load_balance interval with the number of CPUs in the system. | |
6737 | * This trades load-balance latency on larger machines for less cross talk. | |
6738 | */ | |
029632fb | 6739 | void update_max_interval(void) |
49c022e6 PZ |
6740 | { |
6741 | max_load_balance_interval = HZ*num_online_cpus()/10; | |
6742 | } | |
6743 | ||
1e3c88bd PZ |
6744 | /* |
6745 | * It checks each scheduling domain to see if it is due to be balanced, | |
6746 | * and initiates a balancing operation if so. | |
6747 | * | |
b9b0853a | 6748 | * Balancing parameters are set up in init_sched_domains. |
1e3c88bd | 6749 | */ |
f7ed0a89 | 6750 | static void rebalance_domains(struct rq *rq, enum cpu_idle_type idle) |
1e3c88bd | 6751 | { |
23f0d209 | 6752 | int continue_balancing = 1; |
f7ed0a89 | 6753 | int cpu = rq->cpu; |
1e3c88bd | 6754 | unsigned long interval; |
04f733b4 | 6755 | struct sched_domain *sd; |
1e3c88bd PZ |
6756 | /* Earliest time when we have to do rebalance again */ |
6757 | unsigned long next_balance = jiffies + 60*HZ; | |
6758 | int update_next_balance = 0; | |
f48627e6 JL |
6759 | int need_serialize, need_decay = 0; |
6760 | u64 max_cost = 0; | |
1e3c88bd | 6761 | |
48a16753 | 6762 | update_blocked_averages(cpu); |
2069dd75 | 6763 | |
dce840a0 | 6764 | rcu_read_lock(); |
1e3c88bd | 6765 | for_each_domain(cpu, sd) { |
f48627e6 JL |
6766 | /* |
6767 | * Decay the newidle max times here because this is a regular | |
6768 | * visit to all the domains. Decay ~1% per second. | |
6769 | */ | |
6770 | if (time_after(jiffies, sd->next_decay_max_lb_cost)) { | |
6771 | sd->max_newidle_lb_cost = | |
6772 | (sd->max_newidle_lb_cost * 253) / 256; | |
6773 | sd->next_decay_max_lb_cost = jiffies + HZ; | |
6774 | need_decay = 1; | |
6775 | } | |
6776 | max_cost += sd->max_newidle_lb_cost; | |
6777 | ||
1e3c88bd PZ |
6778 | if (!(sd->flags & SD_LOAD_BALANCE)) |
6779 | continue; | |
6780 | ||
f48627e6 JL |
6781 | /* |
6782 | * Stop the load balance at this level. There is another | |
6783 | * CPU in our sched group which is doing load balancing more | |
6784 | * actively. | |
6785 | */ | |
6786 | if (!continue_balancing) { | |
6787 | if (need_decay) | |
6788 | continue; | |
6789 | break; | |
6790 | } | |
6791 | ||
1e3c88bd PZ |
6792 | interval = sd->balance_interval; |
6793 | if (idle != CPU_IDLE) | |
6794 | interval *= sd->busy_factor; | |
6795 | ||
6796 | /* scale ms to jiffies */ | |
6797 | interval = msecs_to_jiffies(interval); | |
49c022e6 | 6798 | interval = clamp(interval, 1UL, max_load_balance_interval); |
1e3c88bd PZ |
6799 | |
6800 | need_serialize = sd->flags & SD_SERIALIZE; | |
6801 | ||
6802 | if (need_serialize) { | |
6803 | if (!spin_trylock(&balancing)) | |
6804 | goto out; | |
6805 | } | |
6806 | ||
6807 | if (time_after_eq(jiffies, sd->last_balance + interval)) { | |
23f0d209 | 6808 | if (load_balance(cpu, rq, sd, idle, &continue_balancing)) { |
1e3c88bd | 6809 | /* |
6263322c | 6810 | * The LBF_DST_PINNED logic could have changed |
de5eb2dd JK |
6811 | * env->dst_cpu, so we can't know our idle |
6812 | * state even if we migrated tasks. Update it. | |
1e3c88bd | 6813 | */ |
de5eb2dd | 6814 | idle = idle_cpu(cpu) ? CPU_IDLE : CPU_NOT_IDLE; |
1e3c88bd PZ |
6815 | } |
6816 | sd->last_balance = jiffies; | |
6817 | } | |
6818 | if (need_serialize) | |
6819 | spin_unlock(&balancing); | |
6820 | out: | |
6821 | if (time_after(next_balance, sd->last_balance + interval)) { | |
6822 | next_balance = sd->last_balance + interval; | |
6823 | update_next_balance = 1; | |
6824 | } | |
f48627e6 JL |
6825 | } |
6826 | if (need_decay) { | |
1e3c88bd | 6827 | /* |
f48627e6 JL |
6828 | * Ensure the rq-wide value also decays but keep it at a |
6829 | * reasonable floor to avoid funnies with rq->avg_idle. | |
1e3c88bd | 6830 | */ |
f48627e6 JL |
6831 | rq->max_idle_balance_cost = |
6832 | max((u64)sysctl_sched_migration_cost, max_cost); | |
1e3c88bd | 6833 | } |
dce840a0 | 6834 | rcu_read_unlock(); |
1e3c88bd PZ |
6835 | |
6836 | /* | |
6837 | * next_balance will be updated only when there is a need. | |
6838 | * When the cpu is attached to null domain for ex, it will not be | |
6839 | * updated. | |
6840 | */ | |
6841 | if (likely(update_next_balance)) | |
6842 | rq->next_balance = next_balance; | |
6843 | } | |
6844 | ||
3451d024 | 6845 | #ifdef CONFIG_NO_HZ_COMMON |
1e3c88bd | 6846 | /* |
3451d024 | 6847 | * In CONFIG_NO_HZ_COMMON case, the idle balance kickee will do the |
1e3c88bd PZ |
6848 | * rebalancing for all the cpus for whom scheduler ticks are stopped. |
6849 | */ | |
208cb16b | 6850 | static void nohz_idle_balance(struct rq *this_rq, enum cpu_idle_type idle) |
83cd4fe2 | 6851 | { |
208cb16b | 6852 | int this_cpu = this_rq->cpu; |
83cd4fe2 VP |
6853 | struct rq *rq; |
6854 | int balance_cpu; | |
6855 | ||
1c792db7 SS |
6856 | if (idle != CPU_IDLE || |
6857 | !test_bit(NOHZ_BALANCE_KICK, nohz_flags(this_cpu))) | |
6858 | goto end; | |
83cd4fe2 VP |
6859 | |
6860 | for_each_cpu(balance_cpu, nohz.idle_cpus_mask) { | |
8a6d42d1 | 6861 | if (balance_cpu == this_cpu || !idle_cpu(balance_cpu)) |
83cd4fe2 VP |
6862 | continue; |
6863 | ||
6864 | /* | |
6865 | * If this cpu gets work to do, stop the load balancing | |
6866 | * work being done for other cpus. Next load | |
6867 | * balancing owner will pick it up. | |
6868 | */ | |
1c792db7 | 6869 | if (need_resched()) |
83cd4fe2 | 6870 | break; |
83cd4fe2 | 6871 | |
5ed4f1d9 VG |
6872 | rq = cpu_rq(balance_cpu); |
6873 | ||
6874 | raw_spin_lock_irq(&rq->lock); | |
6875 | update_rq_clock(rq); | |
6876 | update_idle_cpu_load(rq); | |
6877 | raw_spin_unlock_irq(&rq->lock); | |
83cd4fe2 | 6878 | |
f7ed0a89 | 6879 | rebalance_domains(rq, CPU_IDLE); |
83cd4fe2 | 6880 | |
83cd4fe2 VP |
6881 | if (time_after(this_rq->next_balance, rq->next_balance)) |
6882 | this_rq->next_balance = rq->next_balance; | |
6883 | } | |
6884 | nohz.next_balance = this_rq->next_balance; | |
1c792db7 SS |
6885 | end: |
6886 | clear_bit(NOHZ_BALANCE_KICK, nohz_flags(this_cpu)); | |
83cd4fe2 VP |
6887 | } |
6888 | ||
6889 | /* | |
0b005cf5 SS |
6890 | * Current heuristic for kicking the idle load balancer in the presence |
6891 | * of an idle cpu is the system. | |
6892 | * - This rq has more than one task. | |
6893 | * - At any scheduler domain level, this cpu's scheduler group has multiple | |
6894 | * busy cpu's exceeding the group's power. | |
6895 | * - For SD_ASYM_PACKING, if the lower numbered cpu's in the scheduler | |
6896 | * domain span are idle. | |
83cd4fe2 | 6897 | */ |
4a725627 | 6898 | static inline int nohz_kick_needed(struct rq *rq) |
83cd4fe2 VP |
6899 | { |
6900 | unsigned long now = jiffies; | |
0b005cf5 | 6901 | struct sched_domain *sd; |
37dc6b50 | 6902 | struct sched_group_power *sgp; |
4a725627 | 6903 | int nr_busy, cpu = rq->cpu; |
83cd4fe2 | 6904 | |
4a725627 | 6905 | if (unlikely(rq->idle_balance)) |
83cd4fe2 VP |
6906 | return 0; |
6907 | ||
1c792db7 SS |
6908 | /* |
6909 | * We may be recently in ticked or tickless idle mode. At the first | |
6910 | * busy tick after returning from idle, we will update the busy stats. | |
6911 | */ | |
69e1e811 | 6912 | set_cpu_sd_state_busy(); |
c1cc017c | 6913 | nohz_balance_exit_idle(cpu); |
0b005cf5 SS |
6914 | |
6915 | /* | |
6916 | * None are in tickless mode and hence no need for NOHZ idle load | |
6917 | * balancing. | |
6918 | */ | |
6919 | if (likely(!atomic_read(&nohz.nr_cpus))) | |
6920 | return 0; | |
1c792db7 SS |
6921 | |
6922 | if (time_before(now, nohz.next_balance)) | |
83cd4fe2 VP |
6923 | return 0; |
6924 | ||
0b005cf5 SS |
6925 | if (rq->nr_running >= 2) |
6926 | goto need_kick; | |
83cd4fe2 | 6927 | |
067491b7 | 6928 | rcu_read_lock(); |
37dc6b50 | 6929 | sd = rcu_dereference(per_cpu(sd_busy, cpu)); |
83cd4fe2 | 6930 | |
37dc6b50 PM |
6931 | if (sd) { |
6932 | sgp = sd->groups->sgp; | |
6933 | nr_busy = atomic_read(&sgp->nr_busy_cpus); | |
0b005cf5 | 6934 | |
37dc6b50 | 6935 | if (nr_busy > 1) |
067491b7 | 6936 | goto need_kick_unlock; |
83cd4fe2 | 6937 | } |
37dc6b50 PM |
6938 | |
6939 | sd = rcu_dereference(per_cpu(sd_asym, cpu)); | |
6940 | ||
6941 | if (sd && (cpumask_first_and(nohz.idle_cpus_mask, | |
6942 | sched_domain_span(sd)) < cpu)) | |
6943 | goto need_kick_unlock; | |
6944 | ||
067491b7 | 6945 | rcu_read_unlock(); |
83cd4fe2 | 6946 | return 0; |
067491b7 PZ |
6947 | |
6948 | need_kick_unlock: | |
6949 | rcu_read_unlock(); | |
0b005cf5 SS |
6950 | need_kick: |
6951 | return 1; | |
83cd4fe2 VP |
6952 | } |
6953 | #else | |
208cb16b | 6954 | static void nohz_idle_balance(struct rq *this_rq, enum cpu_idle_type idle) { } |
83cd4fe2 VP |
6955 | #endif |
6956 | ||
6957 | /* | |
6958 | * run_rebalance_domains is triggered when needed from the scheduler tick. | |
6959 | * Also triggered for nohz idle balancing (with nohz_balancing_kick set). | |
6960 | */ | |
1e3c88bd PZ |
6961 | static void run_rebalance_domains(struct softirq_action *h) |
6962 | { | |
208cb16b | 6963 | struct rq *this_rq = this_rq(); |
6eb57e0d | 6964 | enum cpu_idle_type idle = this_rq->idle_balance ? |
1e3c88bd PZ |
6965 | CPU_IDLE : CPU_NOT_IDLE; |
6966 | ||
f7ed0a89 | 6967 | rebalance_domains(this_rq, idle); |
1e3c88bd | 6968 | |
1e3c88bd | 6969 | /* |
83cd4fe2 | 6970 | * If this cpu has a pending nohz_balance_kick, then do the |
1e3c88bd PZ |
6971 | * balancing on behalf of the other idle cpus whose ticks are |
6972 | * stopped. | |
6973 | */ | |
208cb16b | 6974 | nohz_idle_balance(this_rq, idle); |
1e3c88bd PZ |
6975 | } |
6976 | ||
63f609b1 | 6977 | static inline int on_null_domain(struct rq *rq) |
1e3c88bd | 6978 | { |
63f609b1 | 6979 | return !rcu_dereference_sched(rq->sd); |
1e3c88bd PZ |
6980 | } |
6981 | ||
6982 | /* | |
6983 | * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing. | |
1e3c88bd | 6984 | */ |
7caff66f | 6985 | void trigger_load_balance(struct rq *rq) |
1e3c88bd | 6986 | { |
1e3c88bd | 6987 | /* Don't need to rebalance while attached to NULL domain */ |
c726099e DL |
6988 | if (unlikely(on_null_domain(rq))) |
6989 | return; | |
6990 | ||
6991 | if (time_after_eq(jiffies, rq->next_balance)) | |
1e3c88bd | 6992 | raise_softirq(SCHED_SOFTIRQ); |
3451d024 | 6993 | #ifdef CONFIG_NO_HZ_COMMON |
c726099e | 6994 | if (nohz_kick_needed(rq)) |
0aeeeeba | 6995 | nohz_balancer_kick(); |
83cd4fe2 | 6996 | #endif |
1e3c88bd PZ |
6997 | } |
6998 | ||
0bcdcf28 CE |
6999 | static void rq_online_fair(struct rq *rq) |
7000 | { | |
7001 | update_sysctl(); | |
7002 | } | |
7003 | ||
7004 | static void rq_offline_fair(struct rq *rq) | |
7005 | { | |
7006 | update_sysctl(); | |
a4c96ae3 PB |
7007 | |
7008 | /* Ensure any throttled groups are reachable by pick_next_task */ | |
7009 | unthrottle_offline_cfs_rqs(rq); | |
0bcdcf28 CE |
7010 | } |
7011 | ||
55e12e5e | 7012 | #endif /* CONFIG_SMP */ |
e1d1484f | 7013 | |
bf0f6f24 IM |
7014 | /* |
7015 | * scheduler tick hitting a task of our scheduling class: | |
7016 | */ | |
8f4d37ec | 7017 | static void task_tick_fair(struct rq *rq, struct task_struct *curr, int queued) |
bf0f6f24 IM |
7018 | { |
7019 | struct cfs_rq *cfs_rq; | |
7020 | struct sched_entity *se = &curr->se; | |
7021 | ||
7022 | for_each_sched_entity(se) { | |
7023 | cfs_rq = cfs_rq_of(se); | |
8f4d37ec | 7024 | entity_tick(cfs_rq, se, queued); |
bf0f6f24 | 7025 | } |
18bf2805 | 7026 | |
10e84b97 | 7027 | if (numabalancing_enabled) |
cbee9f88 | 7028 | task_tick_numa(rq, curr); |
3d59eebc | 7029 | |
18bf2805 | 7030 | update_rq_runnable_avg(rq, 1); |
bf0f6f24 IM |
7031 | } |
7032 | ||
7033 | /* | |
cd29fe6f PZ |
7034 | * called on fork with the child task as argument from the parent's context |
7035 | * - child not yet on the tasklist | |
7036 | * - preemption disabled | |
bf0f6f24 | 7037 | */ |
cd29fe6f | 7038 | static void task_fork_fair(struct task_struct *p) |
bf0f6f24 | 7039 | { |
4fc420c9 DN |
7040 | struct cfs_rq *cfs_rq; |
7041 | struct sched_entity *se = &p->se, *curr; | |
00bf7bfc | 7042 | int this_cpu = smp_processor_id(); |
cd29fe6f PZ |
7043 | struct rq *rq = this_rq(); |
7044 | unsigned long flags; | |
7045 | ||
05fa785c | 7046 | raw_spin_lock_irqsave(&rq->lock, flags); |
bf0f6f24 | 7047 | |
861d034e PZ |
7048 | update_rq_clock(rq); |
7049 | ||
4fc420c9 DN |
7050 | cfs_rq = task_cfs_rq(current); |
7051 | curr = cfs_rq->curr; | |
7052 | ||
6c9a27f5 DN |
7053 | /* |
7054 | * Not only the cpu but also the task_group of the parent might have | |
7055 | * been changed after parent->se.parent,cfs_rq were copied to | |
7056 | * child->se.parent,cfs_rq. So call __set_task_cpu() to make those | |
7057 | * of child point to valid ones. | |
7058 | */ | |
7059 | rcu_read_lock(); | |
7060 | __set_task_cpu(p, this_cpu); | |
7061 | rcu_read_unlock(); | |
bf0f6f24 | 7062 | |
7109c442 | 7063 | update_curr(cfs_rq); |
cd29fe6f | 7064 | |
b5d9d734 MG |
7065 | if (curr) |
7066 | se->vruntime = curr->vruntime; | |
aeb73b04 | 7067 | place_entity(cfs_rq, se, 1); |
4d78e7b6 | 7068 | |
cd29fe6f | 7069 | if (sysctl_sched_child_runs_first && curr && entity_before(curr, se)) { |
87fefa38 | 7070 | /* |
edcb60a3 IM |
7071 | * Upon rescheduling, sched_class::put_prev_task() will place |
7072 | * 'current' within the tree based on its new key value. | |
7073 | */ | |
4d78e7b6 | 7074 | swap(curr->vruntime, se->vruntime); |
aec0a514 | 7075 | resched_task(rq->curr); |
4d78e7b6 | 7076 | } |
bf0f6f24 | 7077 | |
88ec22d3 PZ |
7078 | se->vruntime -= cfs_rq->min_vruntime; |
7079 | ||
05fa785c | 7080 | raw_spin_unlock_irqrestore(&rq->lock, flags); |
bf0f6f24 IM |
7081 | } |
7082 | ||
cb469845 SR |
7083 | /* |
7084 | * Priority of the task has changed. Check to see if we preempt | |
7085 | * the current task. | |
7086 | */ | |
da7a735e PZ |
7087 | static void |
7088 | prio_changed_fair(struct rq *rq, struct task_struct *p, int oldprio) | |
cb469845 | 7089 | { |
da7a735e PZ |
7090 | if (!p->se.on_rq) |
7091 | return; | |
7092 | ||
cb469845 SR |
7093 | /* |
7094 | * Reschedule if we are currently running on this runqueue and | |
7095 | * our priority decreased, or if we are not currently running on | |
7096 | * this runqueue and our priority is higher than the current's | |
7097 | */ | |
da7a735e | 7098 | if (rq->curr == p) { |
cb469845 SR |
7099 | if (p->prio > oldprio) |
7100 | resched_task(rq->curr); | |
7101 | } else | |
15afe09b | 7102 | check_preempt_curr(rq, p, 0); |
cb469845 SR |
7103 | } |
7104 | ||
da7a735e PZ |
7105 | static void switched_from_fair(struct rq *rq, struct task_struct *p) |
7106 | { | |
7107 | struct sched_entity *se = &p->se; | |
7108 | struct cfs_rq *cfs_rq = cfs_rq_of(se); | |
7109 | ||
7110 | /* | |
7111 | * Ensure the task's vruntime is normalized, so that when its | |
7112 | * switched back to the fair class the enqueue_entity(.flags=0) will | |
7113 | * do the right thing. | |
7114 | * | |
7115 | * If it was on_rq, then the dequeue_entity(.flags=0) will already | |
7116 | * have normalized the vruntime, if it was !on_rq, then only when | |
7117 | * the task is sleeping will it still have non-normalized vruntime. | |
7118 | */ | |
7119 | if (!se->on_rq && p->state != TASK_RUNNING) { | |
7120 | /* | |
7121 | * Fix up our vruntime so that the current sleep doesn't | |
7122 | * cause 'unlimited' sleep bonus. | |
7123 | */ | |
7124 | place_entity(cfs_rq, se, 0); | |
7125 | se->vruntime -= cfs_rq->min_vruntime; | |
7126 | } | |
9ee474f5 | 7127 | |
141965c7 | 7128 | #ifdef CONFIG_SMP |
9ee474f5 PT |
7129 | /* |
7130 | * Remove our load from contribution when we leave sched_fair | |
7131 | * and ensure we don't carry in an old decay_count if we | |
7132 | * switch back. | |
7133 | */ | |
87e3c8ae KT |
7134 | if (se->avg.decay_count) { |
7135 | __synchronize_entity_decay(se); | |
7136 | subtract_blocked_load_contrib(cfs_rq, se->avg.load_avg_contrib); | |
9ee474f5 PT |
7137 | } |
7138 | #endif | |
da7a735e PZ |
7139 | } |
7140 | ||
cb469845 SR |
7141 | /* |
7142 | * We switched to the sched_fair class. | |
7143 | */ | |
da7a735e | 7144 | static void switched_to_fair(struct rq *rq, struct task_struct *p) |
cb469845 | 7145 | { |
da7a735e PZ |
7146 | if (!p->se.on_rq) |
7147 | return; | |
7148 | ||
cb469845 SR |
7149 | /* |
7150 | * We were most likely switched from sched_rt, so | |
7151 | * kick off the schedule if running, otherwise just see | |
7152 | * if we can still preempt the current task. | |
7153 | */ | |
da7a735e | 7154 | if (rq->curr == p) |
cb469845 SR |
7155 | resched_task(rq->curr); |
7156 | else | |
15afe09b | 7157 | check_preempt_curr(rq, p, 0); |
cb469845 SR |
7158 | } |
7159 | ||
83b699ed SV |
7160 | /* Account for a task changing its policy or group. |
7161 | * | |
7162 | * This routine is mostly called to set cfs_rq->curr field when a task | |
7163 | * migrates between groups/classes. | |
7164 | */ | |
7165 | static void set_curr_task_fair(struct rq *rq) | |
7166 | { | |
7167 | struct sched_entity *se = &rq->curr->se; | |
7168 | ||
ec12cb7f PT |
7169 | for_each_sched_entity(se) { |
7170 | struct cfs_rq *cfs_rq = cfs_rq_of(se); | |
7171 | ||
7172 | set_next_entity(cfs_rq, se); | |
7173 | /* ensure bandwidth has been allocated on our new cfs_rq */ | |
7174 | account_cfs_rq_runtime(cfs_rq, 0); | |
7175 | } | |
83b699ed SV |
7176 | } |
7177 | ||
029632fb PZ |
7178 | void init_cfs_rq(struct cfs_rq *cfs_rq) |
7179 | { | |
7180 | cfs_rq->tasks_timeline = RB_ROOT; | |
029632fb PZ |
7181 | cfs_rq->min_vruntime = (u64)(-(1LL << 20)); |
7182 | #ifndef CONFIG_64BIT | |
7183 | cfs_rq->min_vruntime_copy = cfs_rq->min_vruntime; | |
7184 | #endif | |
141965c7 | 7185 | #ifdef CONFIG_SMP |
9ee474f5 | 7186 | atomic64_set(&cfs_rq->decay_counter, 1); |
2509940f | 7187 | atomic_long_set(&cfs_rq->removed_load, 0); |
9ee474f5 | 7188 | #endif |
029632fb PZ |
7189 | } |
7190 | ||
810b3817 | 7191 | #ifdef CONFIG_FAIR_GROUP_SCHED |
b2b5ce02 | 7192 | static void task_move_group_fair(struct task_struct *p, int on_rq) |
810b3817 | 7193 | { |
aff3e498 | 7194 | struct cfs_rq *cfs_rq; |
b2b5ce02 PZ |
7195 | /* |
7196 | * If the task was not on the rq at the time of this cgroup movement | |
7197 | * it must have been asleep, sleeping tasks keep their ->vruntime | |
7198 | * absolute on their old rq until wakeup (needed for the fair sleeper | |
7199 | * bonus in place_entity()). | |
7200 | * | |
7201 | * If it was on the rq, we've just 'preempted' it, which does convert | |
7202 | * ->vruntime to a relative base. | |
7203 | * | |
7204 | * Make sure both cases convert their relative position when migrating | |
7205 | * to another cgroup's rq. This does somewhat interfere with the | |
7206 | * fair sleeper stuff for the first placement, but who cares. | |
7207 | */ | |
7ceff013 DN |
7208 | /* |
7209 | * When !on_rq, vruntime of the task has usually NOT been normalized. | |
7210 | * But there are some cases where it has already been normalized: | |
7211 | * | |
7212 | * - Moving a forked child which is waiting for being woken up by | |
7213 | * wake_up_new_task(). | |
62af3783 DN |
7214 | * - Moving a task which has been woken up by try_to_wake_up() and |
7215 | * waiting for actually being woken up by sched_ttwu_pending(). | |
7ceff013 DN |
7216 | * |
7217 | * To prevent boost or penalty in the new cfs_rq caused by delta | |
7218 | * min_vruntime between the two cfs_rqs, we skip vruntime adjustment. | |
7219 | */ | |
62af3783 | 7220 | if (!on_rq && (!p->se.sum_exec_runtime || p->state == TASK_WAKING)) |
7ceff013 DN |
7221 | on_rq = 1; |
7222 | ||
b2b5ce02 PZ |
7223 | if (!on_rq) |
7224 | p->se.vruntime -= cfs_rq_of(&p->se)->min_vruntime; | |
7225 | set_task_rq(p, task_cpu(p)); | |
aff3e498 PT |
7226 | if (!on_rq) { |
7227 | cfs_rq = cfs_rq_of(&p->se); | |
7228 | p->se.vruntime += cfs_rq->min_vruntime; | |
7229 | #ifdef CONFIG_SMP | |
7230 | /* | |
7231 | * migrate_task_rq_fair() will have removed our previous | |
7232 | * contribution, but we must synchronize for ongoing future | |
7233 | * decay. | |
7234 | */ | |
7235 | p->se.avg.decay_count = atomic64_read(&cfs_rq->decay_counter); | |
7236 | cfs_rq->blocked_load_avg += p->se.avg.load_avg_contrib; | |
7237 | #endif | |
7238 | } | |
810b3817 | 7239 | } |
029632fb PZ |
7240 | |
7241 | void free_fair_sched_group(struct task_group *tg) | |
7242 | { | |
7243 | int i; | |
7244 | ||
7245 | destroy_cfs_bandwidth(tg_cfs_bandwidth(tg)); | |
7246 | ||
7247 | for_each_possible_cpu(i) { | |
7248 | if (tg->cfs_rq) | |
7249 | kfree(tg->cfs_rq[i]); | |
7250 | if (tg->se) | |
7251 | kfree(tg->se[i]); | |
7252 | } | |
7253 | ||
7254 | kfree(tg->cfs_rq); | |
7255 | kfree(tg->se); | |
7256 | } | |
7257 | ||
7258 | int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent) | |
7259 | { | |
7260 | struct cfs_rq *cfs_rq; | |
7261 | struct sched_entity *se; | |
7262 | int i; | |
7263 | ||
7264 | tg->cfs_rq = kzalloc(sizeof(cfs_rq) * nr_cpu_ids, GFP_KERNEL); | |
7265 | if (!tg->cfs_rq) | |
7266 | goto err; | |
7267 | tg->se = kzalloc(sizeof(se) * nr_cpu_ids, GFP_KERNEL); | |
7268 | if (!tg->se) | |
7269 | goto err; | |
7270 | ||
7271 | tg->shares = NICE_0_LOAD; | |
7272 | ||
7273 | init_cfs_bandwidth(tg_cfs_bandwidth(tg)); | |
7274 | ||
7275 | for_each_possible_cpu(i) { | |
7276 | cfs_rq = kzalloc_node(sizeof(struct cfs_rq), | |
7277 | GFP_KERNEL, cpu_to_node(i)); | |
7278 | if (!cfs_rq) | |
7279 | goto err; | |
7280 | ||
7281 | se = kzalloc_node(sizeof(struct sched_entity), | |
7282 | GFP_KERNEL, cpu_to_node(i)); | |
7283 | if (!se) | |
7284 | goto err_free_rq; | |
7285 | ||
7286 | init_cfs_rq(cfs_rq); | |
7287 | init_tg_cfs_entry(tg, cfs_rq, se, i, parent->se[i]); | |
7288 | } | |
7289 | ||
7290 | return 1; | |
7291 | ||
7292 | err_free_rq: | |
7293 | kfree(cfs_rq); | |
7294 | err: | |
7295 | return 0; | |
7296 | } | |
7297 | ||
7298 | void unregister_fair_sched_group(struct task_group *tg, int cpu) | |
7299 | { | |
7300 | struct rq *rq = cpu_rq(cpu); | |
7301 | unsigned long flags; | |
7302 | ||
7303 | /* | |
7304 | * Only empty task groups can be destroyed; so we can speculatively | |
7305 | * check on_list without danger of it being re-added. | |
7306 | */ | |
7307 | if (!tg->cfs_rq[cpu]->on_list) | |
7308 | return; | |
7309 | ||
7310 | raw_spin_lock_irqsave(&rq->lock, flags); | |
7311 | list_del_leaf_cfs_rq(tg->cfs_rq[cpu]); | |
7312 | raw_spin_unlock_irqrestore(&rq->lock, flags); | |
7313 | } | |
7314 | ||
7315 | void init_tg_cfs_entry(struct task_group *tg, struct cfs_rq *cfs_rq, | |
7316 | struct sched_entity *se, int cpu, | |
7317 | struct sched_entity *parent) | |
7318 | { | |
7319 | struct rq *rq = cpu_rq(cpu); | |
7320 | ||
7321 | cfs_rq->tg = tg; | |
7322 | cfs_rq->rq = rq; | |
029632fb PZ |
7323 | init_cfs_rq_runtime(cfs_rq); |
7324 | ||
7325 | tg->cfs_rq[cpu] = cfs_rq; | |
7326 | tg->se[cpu] = se; | |
7327 | ||
7328 | /* se could be NULL for root_task_group */ | |
7329 | if (!se) | |
7330 | return; | |
7331 | ||
7332 | if (!parent) | |
7333 | se->cfs_rq = &rq->cfs; | |
7334 | else | |
7335 | se->cfs_rq = parent->my_q; | |
7336 | ||
7337 | se->my_q = cfs_rq; | |
0ac9b1c2 PT |
7338 | /* guarantee group entities always have weight */ |
7339 | update_load_set(&se->load, NICE_0_LOAD); | |
029632fb PZ |
7340 | se->parent = parent; |
7341 | } | |
7342 | ||
7343 | static DEFINE_MUTEX(shares_mutex); | |
7344 | ||
7345 | int sched_group_set_shares(struct task_group *tg, unsigned long shares) | |
7346 | { | |
7347 | int i; | |
7348 | unsigned long flags; | |
7349 | ||
7350 | /* | |
7351 | * We can't change the weight of the root cgroup. | |
7352 | */ | |
7353 | if (!tg->se[0]) | |
7354 | return -EINVAL; | |
7355 | ||
7356 | shares = clamp(shares, scale_load(MIN_SHARES), scale_load(MAX_SHARES)); | |
7357 | ||
7358 | mutex_lock(&shares_mutex); | |
7359 | if (tg->shares == shares) | |
7360 | goto done; | |
7361 | ||
7362 | tg->shares = shares; | |
7363 | for_each_possible_cpu(i) { | |
7364 | struct rq *rq = cpu_rq(i); | |
7365 | struct sched_entity *se; | |
7366 | ||
7367 | se = tg->se[i]; | |
7368 | /* Propagate contribution to hierarchy */ | |
7369 | raw_spin_lock_irqsave(&rq->lock, flags); | |
71b1da46 FW |
7370 | |
7371 | /* Possible calls to update_curr() need rq clock */ | |
7372 | update_rq_clock(rq); | |
17bc14b7 | 7373 | for_each_sched_entity(se) |
029632fb PZ |
7374 | update_cfs_shares(group_cfs_rq(se)); |
7375 | raw_spin_unlock_irqrestore(&rq->lock, flags); | |
7376 | } | |
7377 | ||
7378 | done: | |
7379 | mutex_unlock(&shares_mutex); | |
7380 | return 0; | |
7381 | } | |
7382 | #else /* CONFIG_FAIR_GROUP_SCHED */ | |
7383 | ||
7384 | void free_fair_sched_group(struct task_group *tg) { } | |
7385 | ||
7386 | int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent) | |
7387 | { | |
7388 | return 1; | |
7389 | } | |
7390 | ||
7391 | void unregister_fair_sched_group(struct task_group *tg, int cpu) { } | |
7392 | ||
7393 | #endif /* CONFIG_FAIR_GROUP_SCHED */ | |
7394 | ||
810b3817 | 7395 | |
6d686f45 | 7396 | static unsigned int get_rr_interval_fair(struct rq *rq, struct task_struct *task) |
0d721cea PW |
7397 | { |
7398 | struct sched_entity *se = &task->se; | |
0d721cea PW |
7399 | unsigned int rr_interval = 0; |
7400 | ||
7401 | /* | |
7402 | * Time slice is 0 for SCHED_OTHER tasks that are on an otherwise | |
7403 | * idle runqueue: | |
7404 | */ | |
0d721cea | 7405 | if (rq->cfs.load.weight) |
a59f4e07 | 7406 | rr_interval = NS_TO_JIFFIES(sched_slice(cfs_rq_of(se), se)); |
0d721cea PW |
7407 | |
7408 | return rr_interval; | |
7409 | } | |
7410 | ||
bf0f6f24 IM |
7411 | /* |
7412 | * All the scheduling class methods: | |
7413 | */ | |
029632fb | 7414 | const struct sched_class fair_sched_class = { |
5522d5d5 | 7415 | .next = &idle_sched_class, |
bf0f6f24 IM |
7416 | .enqueue_task = enqueue_task_fair, |
7417 | .dequeue_task = dequeue_task_fair, | |
7418 | .yield_task = yield_task_fair, | |
d95f4122 | 7419 | .yield_to_task = yield_to_task_fair, |
bf0f6f24 | 7420 | |
2e09bf55 | 7421 | .check_preempt_curr = check_preempt_wakeup, |
bf0f6f24 IM |
7422 | |
7423 | .pick_next_task = pick_next_task_fair, | |
7424 | .put_prev_task = put_prev_task_fair, | |
7425 | ||
681f3e68 | 7426 | #ifdef CONFIG_SMP |
4ce72a2c | 7427 | .select_task_rq = select_task_rq_fair, |
0a74bef8 | 7428 | .migrate_task_rq = migrate_task_rq_fair, |
141965c7 | 7429 | |
0bcdcf28 CE |
7430 | .rq_online = rq_online_fair, |
7431 | .rq_offline = rq_offline_fair, | |
88ec22d3 PZ |
7432 | |
7433 | .task_waking = task_waking_fair, | |
681f3e68 | 7434 | #endif |
bf0f6f24 | 7435 | |
83b699ed | 7436 | .set_curr_task = set_curr_task_fair, |
bf0f6f24 | 7437 | .task_tick = task_tick_fair, |
cd29fe6f | 7438 | .task_fork = task_fork_fair, |
cb469845 SR |
7439 | |
7440 | .prio_changed = prio_changed_fair, | |
da7a735e | 7441 | .switched_from = switched_from_fair, |
cb469845 | 7442 | .switched_to = switched_to_fair, |
810b3817 | 7443 | |
0d721cea PW |
7444 | .get_rr_interval = get_rr_interval_fair, |
7445 | ||
810b3817 | 7446 | #ifdef CONFIG_FAIR_GROUP_SCHED |
b2b5ce02 | 7447 | .task_move_group = task_move_group_fair, |
810b3817 | 7448 | #endif |
bf0f6f24 IM |
7449 | }; |
7450 | ||
7451 | #ifdef CONFIG_SCHED_DEBUG | |
029632fb | 7452 | void print_cfs_stats(struct seq_file *m, int cpu) |
bf0f6f24 | 7453 | { |
bf0f6f24 IM |
7454 | struct cfs_rq *cfs_rq; |
7455 | ||
5973e5b9 | 7456 | rcu_read_lock(); |
c3b64f1e | 7457 | for_each_leaf_cfs_rq(cpu_rq(cpu), cfs_rq) |
5cef9eca | 7458 | print_cfs_rq(m, cpu, cfs_rq); |
5973e5b9 | 7459 | rcu_read_unlock(); |
bf0f6f24 IM |
7460 | } |
7461 | #endif | |
029632fb PZ |
7462 | |
7463 | __init void init_sched_fair_class(void) | |
7464 | { | |
7465 | #ifdef CONFIG_SMP | |
7466 | open_softirq(SCHED_SOFTIRQ, run_rebalance_domains); | |
7467 | ||
3451d024 | 7468 | #ifdef CONFIG_NO_HZ_COMMON |
554cecaf | 7469 | nohz.next_balance = jiffies; |
029632fb | 7470 | zalloc_cpumask_var(&nohz.idle_cpus_mask, GFP_NOWAIT); |
71325960 | 7471 | cpu_notifier(sched_ilb_notifier, 0); |
029632fb PZ |
7472 | #endif |
7473 | #endif /* SMP */ | |
7474 | ||
7475 | } |