Commit | Line | Data |
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bf0f6f24 IM |
1 | /* |
2 | * Completely Fair Scheduling (CFS) Class (SCHED_NORMAL/SCHED_BATCH) | |
3 | * | |
4 | * Copyright (C) 2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> | |
5 | * | |
6 | * Interactivity improvements by Mike Galbraith | |
7 | * (C) 2007 Mike Galbraith <efault@gmx.de> | |
8 | * | |
9 | * Various enhancements by Dmitry Adamushko. | |
10 | * (C) 2007 Dmitry Adamushko <dmitry.adamushko@gmail.com> | |
11 | * | |
12 | * Group scheduling enhancements by Srivatsa Vaddagiri | |
13 | * Copyright IBM Corporation, 2007 | |
14 | * Author: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> | |
15 | * | |
16 | * Scaled math optimizations by Thomas Gleixner | |
17 | * Copyright (C) 2007, Thomas Gleixner <tglx@linutronix.de> | |
21805085 PZ |
18 | * |
19 | * Adaptive scheduling granularity, math enhancements by Peter Zijlstra | |
20 | * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com> | |
bf0f6f24 IM |
21 | */ |
22 | ||
9745512c | 23 | #include <linux/latencytop.h> |
1983a922 | 24 | #include <linux/sched.h> |
9745512c | 25 | |
bf0f6f24 | 26 | /* |
21805085 | 27 | * Targeted preemption latency for CPU-bound tasks: |
864616ee | 28 | * (default: 6ms * (1 + ilog(ncpus)), units: nanoseconds) |
bf0f6f24 | 29 | * |
21805085 | 30 | * NOTE: this latency value is not the same as the concept of |
d274a4ce IM |
31 | * 'timeslice length' - timeslices in CFS are of variable length |
32 | * and have no persistent notion like in traditional, time-slice | |
33 | * based scheduling concepts. | |
bf0f6f24 | 34 | * |
d274a4ce IM |
35 | * (to see the precise effective timeslice length of your workload, |
36 | * run vmstat and monitor the context-switches (cs) field) | |
bf0f6f24 | 37 | */ |
21406928 MG |
38 | unsigned int sysctl_sched_latency = 6000000ULL; |
39 | unsigned int normalized_sysctl_sched_latency = 6000000ULL; | |
2bd8e6d4 | 40 | |
1983a922 CE |
41 | /* |
42 | * The initial- and re-scaling of tunables is configurable | |
43 | * (default SCHED_TUNABLESCALING_LOG = *(1+ilog(ncpus)) | |
44 | * | |
45 | * Options are: | |
46 | * SCHED_TUNABLESCALING_NONE - unscaled, always *1 | |
47 | * SCHED_TUNABLESCALING_LOG - scaled logarithmical, *1+ilog(ncpus) | |
48 | * SCHED_TUNABLESCALING_LINEAR - scaled linear, *ncpus | |
49 | */ | |
50 | enum sched_tunable_scaling sysctl_sched_tunable_scaling | |
51 | = SCHED_TUNABLESCALING_LOG; | |
52 | ||
2bd8e6d4 | 53 | /* |
b2be5e96 | 54 | * Minimal preemption granularity for CPU-bound tasks: |
864616ee | 55 | * (default: 0.75 msec * (1 + ilog(ncpus)), units: nanoseconds) |
2bd8e6d4 | 56 | */ |
0bf377bb IM |
57 | unsigned int sysctl_sched_min_granularity = 750000ULL; |
58 | unsigned int normalized_sysctl_sched_min_granularity = 750000ULL; | |
21805085 PZ |
59 | |
60 | /* | |
b2be5e96 PZ |
61 | * is kept at sysctl_sched_latency / sysctl_sched_min_granularity |
62 | */ | |
0bf377bb | 63 | static unsigned int sched_nr_latency = 8; |
b2be5e96 PZ |
64 | |
65 | /* | |
2bba22c5 | 66 | * After fork, child runs first. If set to 0 (default) then |
b2be5e96 | 67 | * parent will (try to) run first. |
21805085 | 68 | */ |
2bba22c5 | 69 | unsigned int sysctl_sched_child_runs_first __read_mostly; |
bf0f6f24 | 70 | |
1799e35d IM |
71 | /* |
72 | * sys_sched_yield() compat mode | |
73 | * | |
74 | * This option switches the agressive yield implementation of the | |
75 | * old scheduler back on. | |
76 | */ | |
77 | unsigned int __read_mostly sysctl_sched_compat_yield; | |
78 | ||
bf0f6f24 IM |
79 | /* |
80 | * SCHED_OTHER wake-up granularity. | |
172e082a | 81 | * (default: 1 msec * (1 + ilog(ncpus)), units: nanoseconds) |
bf0f6f24 IM |
82 | * |
83 | * This option delays the preemption effects of decoupled workloads | |
84 | * and reduces their over-scheduling. Synchronous workloads will still | |
85 | * have immediate wakeup/sleep latencies. | |
86 | */ | |
172e082a | 87 | unsigned int sysctl_sched_wakeup_granularity = 1000000UL; |
0bcdcf28 | 88 | unsigned int normalized_sysctl_sched_wakeup_granularity = 1000000UL; |
bf0f6f24 | 89 | |
da84d961 IM |
90 | const_debug unsigned int sysctl_sched_migration_cost = 500000UL; |
91 | ||
a7a4f8a7 PT |
92 | /* |
93 | * The exponential sliding window over which load is averaged for shares | |
94 | * distribution. | |
95 | * (default: 10msec) | |
96 | */ | |
97 | unsigned int __read_mostly sysctl_sched_shares_window = 10000000UL; | |
98 | ||
a4c2f00f PZ |
99 | static const struct sched_class fair_sched_class; |
100 | ||
bf0f6f24 IM |
101 | /************************************************************** |
102 | * CFS operations on generic schedulable entities: | |
103 | */ | |
104 | ||
62160e3f | 105 | #ifdef CONFIG_FAIR_GROUP_SCHED |
bf0f6f24 | 106 | |
62160e3f | 107 | /* cpu runqueue to which this cfs_rq is attached */ |
bf0f6f24 IM |
108 | static inline struct rq *rq_of(struct cfs_rq *cfs_rq) |
109 | { | |
62160e3f | 110 | return cfs_rq->rq; |
bf0f6f24 IM |
111 | } |
112 | ||
62160e3f IM |
113 | /* An entity is a task if it doesn't "own" a runqueue */ |
114 | #define entity_is_task(se) (!se->my_q) | |
bf0f6f24 | 115 | |
8f48894f PZ |
116 | static inline struct task_struct *task_of(struct sched_entity *se) |
117 | { | |
118 | #ifdef CONFIG_SCHED_DEBUG | |
119 | WARN_ON_ONCE(!entity_is_task(se)); | |
120 | #endif | |
121 | return container_of(se, struct task_struct, se); | |
122 | } | |
123 | ||
b758149c PZ |
124 | /* Walk up scheduling entities hierarchy */ |
125 | #define for_each_sched_entity(se) \ | |
126 | for (; se; se = se->parent) | |
127 | ||
128 | static inline struct cfs_rq *task_cfs_rq(struct task_struct *p) | |
129 | { | |
130 | return p->se.cfs_rq; | |
131 | } | |
132 | ||
133 | /* runqueue on which this entity is (to be) queued */ | |
134 | static inline struct cfs_rq *cfs_rq_of(struct sched_entity *se) | |
135 | { | |
136 | return se->cfs_rq; | |
137 | } | |
138 | ||
139 | /* runqueue "owned" by this group */ | |
140 | static inline struct cfs_rq *group_cfs_rq(struct sched_entity *grp) | |
141 | { | |
142 | return grp->my_q; | |
143 | } | |
144 | ||
145 | /* Given a group's cfs_rq on one cpu, return its corresponding cfs_rq on | |
146 | * another cpu ('this_cpu') | |
147 | */ | |
148 | static inline struct cfs_rq *cpu_cfs_rq(struct cfs_rq *cfs_rq, int this_cpu) | |
149 | { | |
150 | return cfs_rq->tg->cfs_rq[this_cpu]; | |
151 | } | |
152 | ||
3d4b47b4 PZ |
153 | static inline void list_add_leaf_cfs_rq(struct cfs_rq *cfs_rq) |
154 | { | |
155 | if (!cfs_rq->on_list) { | |
67e86250 PT |
156 | /* |
157 | * Ensure we either appear before our parent (if already | |
158 | * enqueued) or force our parent to appear after us when it is | |
159 | * enqueued. The fact that we always enqueue bottom-up | |
160 | * reduces this to two cases. | |
161 | */ | |
162 | if (cfs_rq->tg->parent && | |
163 | cfs_rq->tg->parent->cfs_rq[cpu_of(rq_of(cfs_rq))]->on_list) { | |
164 | list_add_rcu(&cfs_rq->leaf_cfs_rq_list, | |
165 | &rq_of(cfs_rq)->leaf_cfs_rq_list); | |
166 | } else { | |
167 | list_add_tail_rcu(&cfs_rq->leaf_cfs_rq_list, | |
3d4b47b4 | 168 | &rq_of(cfs_rq)->leaf_cfs_rq_list); |
67e86250 | 169 | } |
3d4b47b4 PZ |
170 | |
171 | cfs_rq->on_list = 1; | |
172 | } | |
173 | } | |
174 | ||
175 | static inline void list_del_leaf_cfs_rq(struct cfs_rq *cfs_rq) | |
176 | { | |
177 | if (cfs_rq->on_list) { | |
178 | list_del_rcu(&cfs_rq->leaf_cfs_rq_list); | |
179 | cfs_rq->on_list = 0; | |
180 | } | |
181 | } | |
182 | ||
b758149c PZ |
183 | /* Iterate thr' all leaf cfs_rq's on a runqueue */ |
184 | #define for_each_leaf_cfs_rq(rq, cfs_rq) \ | |
185 | list_for_each_entry_rcu(cfs_rq, &rq->leaf_cfs_rq_list, leaf_cfs_rq_list) | |
186 | ||
187 | /* Do the two (enqueued) entities belong to the same group ? */ | |
188 | static inline int | |
189 | is_same_group(struct sched_entity *se, struct sched_entity *pse) | |
190 | { | |
191 | if (se->cfs_rq == pse->cfs_rq) | |
192 | return 1; | |
193 | ||
194 | return 0; | |
195 | } | |
196 | ||
197 | static inline struct sched_entity *parent_entity(struct sched_entity *se) | |
198 | { | |
199 | return se->parent; | |
200 | } | |
201 | ||
464b7527 PZ |
202 | /* return depth at which a sched entity is present in the hierarchy */ |
203 | static inline int depth_se(struct sched_entity *se) | |
204 | { | |
205 | int depth = 0; | |
206 | ||
207 | for_each_sched_entity(se) | |
208 | depth++; | |
209 | ||
210 | return depth; | |
211 | } | |
212 | ||
213 | static void | |
214 | find_matching_se(struct sched_entity **se, struct sched_entity **pse) | |
215 | { | |
216 | int se_depth, pse_depth; | |
217 | ||
218 | /* | |
219 | * preemption test can be made between sibling entities who are in the | |
220 | * same cfs_rq i.e who have a common parent. Walk up the hierarchy of | |
221 | * both tasks until we find their ancestors who are siblings of common | |
222 | * parent. | |
223 | */ | |
224 | ||
225 | /* First walk up until both entities are at same depth */ | |
226 | se_depth = depth_se(*se); | |
227 | pse_depth = depth_se(*pse); | |
228 | ||
229 | while (se_depth > pse_depth) { | |
230 | se_depth--; | |
231 | *se = parent_entity(*se); | |
232 | } | |
233 | ||
234 | while (pse_depth > se_depth) { | |
235 | pse_depth--; | |
236 | *pse = parent_entity(*pse); | |
237 | } | |
238 | ||
239 | while (!is_same_group(*se, *pse)) { | |
240 | *se = parent_entity(*se); | |
241 | *pse = parent_entity(*pse); | |
242 | } | |
243 | } | |
244 | ||
8f48894f PZ |
245 | #else /* !CONFIG_FAIR_GROUP_SCHED */ |
246 | ||
247 | static inline struct task_struct *task_of(struct sched_entity *se) | |
248 | { | |
249 | return container_of(se, struct task_struct, se); | |
250 | } | |
bf0f6f24 | 251 | |
62160e3f IM |
252 | static inline struct rq *rq_of(struct cfs_rq *cfs_rq) |
253 | { | |
254 | return container_of(cfs_rq, struct rq, cfs); | |
bf0f6f24 IM |
255 | } |
256 | ||
257 | #define entity_is_task(se) 1 | |
258 | ||
b758149c PZ |
259 | #define for_each_sched_entity(se) \ |
260 | for (; se; se = NULL) | |
bf0f6f24 | 261 | |
b758149c | 262 | static inline struct cfs_rq *task_cfs_rq(struct task_struct *p) |
bf0f6f24 | 263 | { |
b758149c | 264 | return &task_rq(p)->cfs; |
bf0f6f24 IM |
265 | } |
266 | ||
b758149c PZ |
267 | static inline struct cfs_rq *cfs_rq_of(struct sched_entity *se) |
268 | { | |
269 | struct task_struct *p = task_of(se); | |
270 | struct rq *rq = task_rq(p); | |
271 | ||
272 | return &rq->cfs; | |
273 | } | |
274 | ||
275 | /* runqueue "owned" by this group */ | |
276 | static inline struct cfs_rq *group_cfs_rq(struct sched_entity *grp) | |
277 | { | |
278 | return NULL; | |
279 | } | |
280 | ||
281 | static inline struct cfs_rq *cpu_cfs_rq(struct cfs_rq *cfs_rq, int this_cpu) | |
282 | { | |
283 | return &cpu_rq(this_cpu)->cfs; | |
284 | } | |
285 | ||
3d4b47b4 PZ |
286 | static inline void list_add_leaf_cfs_rq(struct cfs_rq *cfs_rq) |
287 | { | |
288 | } | |
289 | ||
290 | static inline void list_del_leaf_cfs_rq(struct cfs_rq *cfs_rq) | |
291 | { | |
292 | } | |
293 | ||
b758149c PZ |
294 | #define for_each_leaf_cfs_rq(rq, cfs_rq) \ |
295 | for (cfs_rq = &rq->cfs; cfs_rq; cfs_rq = NULL) | |
296 | ||
297 | static inline int | |
298 | is_same_group(struct sched_entity *se, struct sched_entity *pse) | |
299 | { | |
300 | return 1; | |
301 | } | |
302 | ||
303 | static inline struct sched_entity *parent_entity(struct sched_entity *se) | |
304 | { | |
305 | return NULL; | |
306 | } | |
307 | ||
464b7527 PZ |
308 | static inline void |
309 | find_matching_se(struct sched_entity **se, struct sched_entity **pse) | |
310 | { | |
311 | } | |
312 | ||
b758149c PZ |
313 | #endif /* CONFIG_FAIR_GROUP_SCHED */ |
314 | ||
bf0f6f24 IM |
315 | |
316 | /************************************************************** | |
317 | * Scheduling class tree data structure manipulation methods: | |
318 | */ | |
319 | ||
0702e3eb | 320 | static inline u64 max_vruntime(u64 min_vruntime, u64 vruntime) |
02e0431a | 321 | { |
368059a9 PZ |
322 | s64 delta = (s64)(vruntime - min_vruntime); |
323 | if (delta > 0) | |
02e0431a PZ |
324 | min_vruntime = vruntime; |
325 | ||
326 | return min_vruntime; | |
327 | } | |
328 | ||
0702e3eb | 329 | static inline u64 min_vruntime(u64 min_vruntime, u64 vruntime) |
b0ffd246 PZ |
330 | { |
331 | s64 delta = (s64)(vruntime - min_vruntime); | |
332 | if (delta < 0) | |
333 | min_vruntime = vruntime; | |
334 | ||
335 | return min_vruntime; | |
336 | } | |
337 | ||
54fdc581 FC |
338 | static inline int entity_before(struct sched_entity *a, |
339 | struct sched_entity *b) | |
340 | { | |
341 | return (s64)(a->vruntime - b->vruntime) < 0; | |
342 | } | |
343 | ||
0702e3eb | 344 | static inline s64 entity_key(struct cfs_rq *cfs_rq, struct sched_entity *se) |
9014623c | 345 | { |
30cfdcfc | 346 | return se->vruntime - cfs_rq->min_vruntime; |
9014623c PZ |
347 | } |
348 | ||
1af5f730 PZ |
349 | static void update_min_vruntime(struct cfs_rq *cfs_rq) |
350 | { | |
351 | u64 vruntime = cfs_rq->min_vruntime; | |
352 | ||
353 | if (cfs_rq->curr) | |
354 | vruntime = cfs_rq->curr->vruntime; | |
355 | ||
356 | if (cfs_rq->rb_leftmost) { | |
357 | struct sched_entity *se = rb_entry(cfs_rq->rb_leftmost, | |
358 | struct sched_entity, | |
359 | run_node); | |
360 | ||
e17036da | 361 | if (!cfs_rq->curr) |
1af5f730 PZ |
362 | vruntime = se->vruntime; |
363 | else | |
364 | vruntime = min_vruntime(vruntime, se->vruntime); | |
365 | } | |
366 | ||
367 | cfs_rq->min_vruntime = max_vruntime(cfs_rq->min_vruntime, vruntime); | |
368 | } | |
369 | ||
bf0f6f24 IM |
370 | /* |
371 | * Enqueue an entity into the rb-tree: | |
372 | */ | |
0702e3eb | 373 | static void __enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 IM |
374 | { |
375 | struct rb_node **link = &cfs_rq->tasks_timeline.rb_node; | |
376 | struct rb_node *parent = NULL; | |
377 | struct sched_entity *entry; | |
9014623c | 378 | s64 key = entity_key(cfs_rq, se); |
bf0f6f24 IM |
379 | int leftmost = 1; |
380 | ||
381 | /* | |
382 | * Find the right place in the rbtree: | |
383 | */ | |
384 | while (*link) { | |
385 | parent = *link; | |
386 | entry = rb_entry(parent, struct sched_entity, run_node); | |
387 | /* | |
388 | * We dont care about collisions. Nodes with | |
389 | * the same key stay together. | |
390 | */ | |
9014623c | 391 | if (key < entity_key(cfs_rq, entry)) { |
bf0f6f24 IM |
392 | link = &parent->rb_left; |
393 | } else { | |
394 | link = &parent->rb_right; | |
395 | leftmost = 0; | |
396 | } | |
397 | } | |
398 | ||
399 | /* | |
400 | * Maintain a cache of leftmost tree entries (it is frequently | |
401 | * used): | |
402 | */ | |
1af5f730 | 403 | if (leftmost) |
57cb499d | 404 | cfs_rq->rb_leftmost = &se->run_node; |
bf0f6f24 IM |
405 | |
406 | rb_link_node(&se->run_node, parent, link); | |
407 | rb_insert_color(&se->run_node, &cfs_rq->tasks_timeline); | |
bf0f6f24 IM |
408 | } |
409 | ||
0702e3eb | 410 | static void __dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 411 | { |
3fe69747 PZ |
412 | if (cfs_rq->rb_leftmost == &se->run_node) { |
413 | struct rb_node *next_node; | |
3fe69747 PZ |
414 | |
415 | next_node = rb_next(&se->run_node); | |
416 | cfs_rq->rb_leftmost = next_node; | |
3fe69747 | 417 | } |
e9acbff6 | 418 | |
bf0f6f24 | 419 | rb_erase(&se->run_node, &cfs_rq->tasks_timeline); |
bf0f6f24 IM |
420 | } |
421 | ||
bf0f6f24 IM |
422 | static struct sched_entity *__pick_next_entity(struct cfs_rq *cfs_rq) |
423 | { | |
f4b6755f PZ |
424 | struct rb_node *left = cfs_rq->rb_leftmost; |
425 | ||
426 | if (!left) | |
427 | return NULL; | |
428 | ||
429 | return rb_entry(left, struct sched_entity, run_node); | |
bf0f6f24 IM |
430 | } |
431 | ||
f4b6755f | 432 | static struct sched_entity *__pick_last_entity(struct cfs_rq *cfs_rq) |
aeb73b04 | 433 | { |
7eee3e67 | 434 | struct rb_node *last = rb_last(&cfs_rq->tasks_timeline); |
aeb73b04 | 435 | |
70eee74b BS |
436 | if (!last) |
437 | return NULL; | |
7eee3e67 IM |
438 | |
439 | return rb_entry(last, struct sched_entity, run_node); | |
aeb73b04 PZ |
440 | } |
441 | ||
bf0f6f24 IM |
442 | /************************************************************** |
443 | * Scheduling class statistics methods: | |
444 | */ | |
445 | ||
b2be5e96 | 446 | #ifdef CONFIG_SCHED_DEBUG |
acb4a848 | 447 | int sched_proc_update_handler(struct ctl_table *table, int write, |
8d65af78 | 448 | void __user *buffer, size_t *lenp, |
b2be5e96 PZ |
449 | loff_t *ppos) |
450 | { | |
8d65af78 | 451 | int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); |
acb4a848 | 452 | int factor = get_update_sysctl_factor(); |
b2be5e96 PZ |
453 | |
454 | if (ret || !write) | |
455 | return ret; | |
456 | ||
457 | sched_nr_latency = DIV_ROUND_UP(sysctl_sched_latency, | |
458 | sysctl_sched_min_granularity); | |
459 | ||
acb4a848 CE |
460 | #define WRT_SYSCTL(name) \ |
461 | (normalized_sysctl_##name = sysctl_##name / (factor)) | |
462 | WRT_SYSCTL(sched_min_granularity); | |
463 | WRT_SYSCTL(sched_latency); | |
464 | WRT_SYSCTL(sched_wakeup_granularity); | |
acb4a848 CE |
465 | #undef WRT_SYSCTL |
466 | ||
b2be5e96 PZ |
467 | return 0; |
468 | } | |
469 | #endif | |
647e7cac | 470 | |
a7be37ac | 471 | /* |
f9c0b095 | 472 | * delta /= w |
a7be37ac PZ |
473 | */ |
474 | static inline unsigned long | |
475 | calc_delta_fair(unsigned long delta, struct sched_entity *se) | |
476 | { | |
f9c0b095 PZ |
477 | if (unlikely(se->load.weight != NICE_0_LOAD)) |
478 | delta = calc_delta_mine(delta, NICE_0_LOAD, &se->load); | |
a7be37ac PZ |
479 | |
480 | return delta; | |
481 | } | |
482 | ||
647e7cac IM |
483 | /* |
484 | * The idea is to set a period in which each task runs once. | |
485 | * | |
486 | * When there are too many tasks (sysctl_sched_nr_latency) we have to stretch | |
487 | * this period because otherwise the slices get too small. | |
488 | * | |
489 | * p = (nr <= nl) ? l : l*nr/nl | |
490 | */ | |
4d78e7b6 PZ |
491 | static u64 __sched_period(unsigned long nr_running) |
492 | { | |
493 | u64 period = sysctl_sched_latency; | |
b2be5e96 | 494 | unsigned long nr_latency = sched_nr_latency; |
4d78e7b6 PZ |
495 | |
496 | if (unlikely(nr_running > nr_latency)) { | |
4bf0b771 | 497 | period = sysctl_sched_min_granularity; |
4d78e7b6 | 498 | period *= nr_running; |
4d78e7b6 PZ |
499 | } |
500 | ||
501 | return period; | |
502 | } | |
503 | ||
647e7cac IM |
504 | /* |
505 | * We calculate the wall-time slice from the period by taking a part | |
506 | * proportional to the weight. | |
507 | * | |
f9c0b095 | 508 | * s = p*P[w/rw] |
647e7cac | 509 | */ |
6d0f0ebd | 510 | static u64 sched_slice(struct cfs_rq *cfs_rq, struct sched_entity *se) |
21805085 | 511 | { |
0a582440 | 512 | u64 slice = __sched_period(cfs_rq->nr_running + !se->on_rq); |
f9c0b095 | 513 | |
0a582440 | 514 | for_each_sched_entity(se) { |
6272d68c | 515 | struct load_weight *load; |
3104bf03 | 516 | struct load_weight lw; |
6272d68c LM |
517 | |
518 | cfs_rq = cfs_rq_of(se); | |
519 | load = &cfs_rq->load; | |
f9c0b095 | 520 | |
0a582440 | 521 | if (unlikely(!se->on_rq)) { |
3104bf03 | 522 | lw = cfs_rq->load; |
0a582440 MG |
523 | |
524 | update_load_add(&lw, se->load.weight); | |
525 | load = &lw; | |
526 | } | |
527 | slice = calc_delta_mine(slice, se->load.weight, load); | |
528 | } | |
529 | return slice; | |
bf0f6f24 IM |
530 | } |
531 | ||
647e7cac | 532 | /* |
ac884dec | 533 | * We calculate the vruntime slice of a to be inserted task |
647e7cac | 534 | * |
f9c0b095 | 535 | * vs = s/w |
647e7cac | 536 | */ |
f9c0b095 | 537 | static u64 sched_vslice(struct cfs_rq *cfs_rq, struct sched_entity *se) |
67e9fb2a | 538 | { |
f9c0b095 | 539 | return calc_delta_fair(sched_slice(cfs_rq, se), se); |
a7be37ac PZ |
540 | } |
541 | ||
bf0f6f24 IM |
542 | /* |
543 | * Update the current task's runtime statistics. Skip current tasks that | |
544 | * are not in our scheduling class. | |
545 | */ | |
546 | static inline void | |
8ebc91d9 IM |
547 | __update_curr(struct cfs_rq *cfs_rq, struct sched_entity *curr, |
548 | unsigned long delta_exec) | |
bf0f6f24 | 549 | { |
bbdba7c0 | 550 | unsigned long delta_exec_weighted; |
bf0f6f24 | 551 | |
41acab88 LDM |
552 | schedstat_set(curr->statistics.exec_max, |
553 | max((u64)delta_exec, curr->statistics.exec_max)); | |
bf0f6f24 IM |
554 | |
555 | curr->sum_exec_runtime += delta_exec; | |
7a62eabc | 556 | schedstat_add(cfs_rq, exec_clock, delta_exec); |
a7be37ac | 557 | delta_exec_weighted = calc_delta_fair(delta_exec, curr); |
88ec22d3 | 558 | |
e9acbff6 | 559 | curr->vruntime += delta_exec_weighted; |
1af5f730 | 560 | update_min_vruntime(cfs_rq); |
bf0f6f24 IM |
561 | } |
562 | ||
b7cc0896 | 563 | static void update_curr(struct cfs_rq *cfs_rq) |
bf0f6f24 | 564 | { |
429d43bc | 565 | struct sched_entity *curr = cfs_rq->curr; |
305e6835 | 566 | u64 now = rq_of(cfs_rq)->clock_task; |
bf0f6f24 IM |
567 | unsigned long delta_exec; |
568 | ||
569 | if (unlikely(!curr)) | |
570 | return; | |
571 | ||
572 | /* | |
573 | * Get the amount of time the current task was running | |
574 | * since the last time we changed load (this cannot | |
575 | * overflow on 32 bits): | |
576 | */ | |
8ebc91d9 | 577 | delta_exec = (unsigned long)(now - curr->exec_start); |
34f28ecd PZ |
578 | if (!delta_exec) |
579 | return; | |
bf0f6f24 | 580 | |
8ebc91d9 IM |
581 | __update_curr(cfs_rq, curr, delta_exec); |
582 | curr->exec_start = now; | |
d842de87 SV |
583 | |
584 | if (entity_is_task(curr)) { | |
585 | struct task_struct *curtask = task_of(curr); | |
586 | ||
f977bb49 | 587 | trace_sched_stat_runtime(curtask, delta_exec, curr->vruntime); |
d842de87 | 588 | cpuacct_charge(curtask, delta_exec); |
f06febc9 | 589 | account_group_exec_runtime(curtask, delta_exec); |
d842de87 | 590 | } |
bf0f6f24 IM |
591 | } |
592 | ||
593 | static inline void | |
5870db5b | 594 | update_stats_wait_start(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 595 | { |
41acab88 | 596 | schedstat_set(se->statistics.wait_start, rq_of(cfs_rq)->clock); |
bf0f6f24 IM |
597 | } |
598 | ||
bf0f6f24 IM |
599 | /* |
600 | * Task is being enqueued - update stats: | |
601 | */ | |
d2417e5a | 602 | static void update_stats_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 603 | { |
bf0f6f24 IM |
604 | /* |
605 | * Are we enqueueing a waiting task? (for current tasks | |
606 | * a dequeue/enqueue event is a NOP) | |
607 | */ | |
429d43bc | 608 | if (se != cfs_rq->curr) |
5870db5b | 609 | update_stats_wait_start(cfs_rq, se); |
bf0f6f24 IM |
610 | } |
611 | ||
bf0f6f24 | 612 | static void |
9ef0a961 | 613 | update_stats_wait_end(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 614 | { |
41acab88 LDM |
615 | schedstat_set(se->statistics.wait_max, max(se->statistics.wait_max, |
616 | rq_of(cfs_rq)->clock - se->statistics.wait_start)); | |
617 | schedstat_set(se->statistics.wait_count, se->statistics.wait_count + 1); | |
618 | schedstat_set(se->statistics.wait_sum, se->statistics.wait_sum + | |
619 | rq_of(cfs_rq)->clock - se->statistics.wait_start); | |
768d0c27 PZ |
620 | #ifdef CONFIG_SCHEDSTATS |
621 | if (entity_is_task(se)) { | |
622 | trace_sched_stat_wait(task_of(se), | |
41acab88 | 623 | rq_of(cfs_rq)->clock - se->statistics.wait_start); |
768d0c27 PZ |
624 | } |
625 | #endif | |
41acab88 | 626 | schedstat_set(se->statistics.wait_start, 0); |
bf0f6f24 IM |
627 | } |
628 | ||
629 | static inline void | |
19b6a2e3 | 630 | update_stats_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 631 | { |
bf0f6f24 IM |
632 | /* |
633 | * Mark the end of the wait period if dequeueing a | |
634 | * waiting task: | |
635 | */ | |
429d43bc | 636 | if (se != cfs_rq->curr) |
9ef0a961 | 637 | update_stats_wait_end(cfs_rq, se); |
bf0f6f24 IM |
638 | } |
639 | ||
640 | /* | |
641 | * We are picking a new current task - update its stats: | |
642 | */ | |
643 | static inline void | |
79303e9e | 644 | update_stats_curr_start(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 IM |
645 | { |
646 | /* | |
647 | * We are starting a new run period: | |
648 | */ | |
305e6835 | 649 | se->exec_start = rq_of(cfs_rq)->clock_task; |
bf0f6f24 IM |
650 | } |
651 | ||
bf0f6f24 IM |
652 | /************************************************** |
653 | * Scheduling class queueing methods: | |
654 | */ | |
655 | ||
c09595f6 PZ |
656 | #if defined CONFIG_SMP && defined CONFIG_FAIR_GROUP_SCHED |
657 | static void | |
658 | add_cfs_task_weight(struct cfs_rq *cfs_rq, unsigned long weight) | |
659 | { | |
660 | cfs_rq->task_weight += weight; | |
661 | } | |
662 | #else | |
663 | static inline void | |
664 | add_cfs_task_weight(struct cfs_rq *cfs_rq, unsigned long weight) | |
665 | { | |
666 | } | |
667 | #endif | |
668 | ||
30cfdcfc DA |
669 | static void |
670 | account_entity_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se) | |
671 | { | |
672 | update_load_add(&cfs_rq->load, se->load.weight); | |
c09595f6 PZ |
673 | if (!parent_entity(se)) |
674 | inc_cpu_load(rq_of(cfs_rq), se->load.weight); | |
b87f1724 | 675 | if (entity_is_task(se)) { |
c09595f6 | 676 | add_cfs_task_weight(cfs_rq, se->load.weight); |
b87f1724 BR |
677 | list_add(&se->group_node, &cfs_rq->tasks); |
678 | } | |
30cfdcfc | 679 | cfs_rq->nr_running++; |
30cfdcfc DA |
680 | } |
681 | ||
682 | static void | |
683 | account_entity_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se) | |
684 | { | |
685 | update_load_sub(&cfs_rq->load, se->load.weight); | |
c09595f6 PZ |
686 | if (!parent_entity(se)) |
687 | dec_cpu_load(rq_of(cfs_rq), se->load.weight); | |
b87f1724 | 688 | if (entity_is_task(se)) { |
c09595f6 | 689 | add_cfs_task_weight(cfs_rq, -se->load.weight); |
b87f1724 BR |
690 | list_del_init(&se->group_node); |
691 | } | |
30cfdcfc | 692 | cfs_rq->nr_running--; |
30cfdcfc DA |
693 | } |
694 | ||
2069dd75 | 695 | #if defined CONFIG_SMP && defined CONFIG_FAIR_GROUP_SCHED |
e33078ba | 696 | static void update_cfs_load(struct cfs_rq *cfs_rq) |
2069dd75 | 697 | { |
a7a4f8a7 | 698 | u64 period = sysctl_sched_shares_window; |
2069dd75 | 699 | u64 now, delta; |
e33078ba | 700 | unsigned long load = cfs_rq->load.weight; |
2069dd75 PZ |
701 | |
702 | if (!cfs_rq) | |
703 | return; | |
704 | ||
705 | now = rq_of(cfs_rq)->clock; | |
706 | delta = now - cfs_rq->load_stamp; | |
707 | ||
e33078ba PT |
708 | /* truncate load history at 4 idle periods */ |
709 | if (cfs_rq->load_stamp > cfs_rq->load_last && | |
710 | now - cfs_rq->load_last > 4 * period) { | |
711 | cfs_rq->load_period = 0; | |
712 | cfs_rq->load_avg = 0; | |
713 | } | |
714 | ||
2069dd75 PZ |
715 | cfs_rq->load_stamp = now; |
716 | cfs_rq->load_period += delta; | |
e33078ba PT |
717 | if (load) { |
718 | cfs_rq->load_last = now; | |
719 | cfs_rq->load_avg += delta * load; | |
720 | } | |
2069dd75 PZ |
721 | |
722 | while (cfs_rq->load_period > period) { | |
723 | /* | |
724 | * Inline assembly required to prevent the compiler | |
725 | * optimising this loop into a divmod call. | |
726 | * See __iter_div_u64_rem() for another example of this. | |
727 | */ | |
728 | asm("" : "+rm" (cfs_rq->load_period)); | |
729 | cfs_rq->load_period /= 2; | |
730 | cfs_rq->load_avg /= 2; | |
731 | } | |
3d4b47b4 | 732 | |
e33078ba PT |
733 | if (!cfs_rq->curr && !cfs_rq->nr_running && !cfs_rq->load_avg) |
734 | list_del_leaf_cfs_rq(cfs_rq); | |
2069dd75 PZ |
735 | } |
736 | ||
737 | static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, | |
738 | unsigned long weight) | |
739 | { | |
740 | if (se->on_rq) | |
741 | account_entity_dequeue(cfs_rq, se); | |
742 | ||
743 | update_load_set(&se->load, weight); | |
744 | ||
745 | if (se->on_rq) | |
746 | account_entity_enqueue(cfs_rq, se); | |
747 | } | |
748 | ||
f0d7442a | 749 | static void update_cfs_shares(struct cfs_rq *cfs_rq, long weight_delta) |
2069dd75 PZ |
750 | { |
751 | struct task_group *tg; | |
752 | struct sched_entity *se; | |
753 | long load_weight, load, shares; | |
754 | ||
755 | if (!cfs_rq) | |
756 | return; | |
757 | ||
758 | tg = cfs_rq->tg; | |
759 | se = tg->se[cpu_of(rq_of(cfs_rq))]; | |
760 | if (!se) | |
761 | return; | |
762 | ||
f0d7442a | 763 | load = cfs_rq->load.weight + weight_delta; |
2069dd75 PZ |
764 | |
765 | load_weight = atomic_read(&tg->load_weight); | |
766 | load_weight -= cfs_rq->load_contribution; | |
767 | load_weight += load; | |
768 | ||
769 | shares = (tg->shares * load); | |
770 | if (load_weight) | |
771 | shares /= load_weight; | |
772 | ||
773 | if (shares < MIN_SHARES) | |
774 | shares = MIN_SHARES; | |
775 | if (shares > tg->shares) | |
776 | shares = tg->shares; | |
777 | ||
778 | reweight_entity(cfs_rq_of(se), se, shares); | |
779 | } | |
780 | #else /* CONFIG_FAIR_GROUP_SCHED */ | |
e33078ba | 781 | static inline void update_cfs_load(struct cfs_rq *cfs_rq) |
2069dd75 PZ |
782 | { |
783 | } | |
784 | ||
f0d7442a | 785 | static inline void update_cfs_shares(struct cfs_rq *cfs_rq, long weight_delta) |
2069dd75 PZ |
786 | { |
787 | } | |
788 | #endif /* CONFIG_FAIR_GROUP_SCHED */ | |
789 | ||
2396af69 | 790 | static void enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 791 | { |
bf0f6f24 | 792 | #ifdef CONFIG_SCHEDSTATS |
e414314c PZ |
793 | struct task_struct *tsk = NULL; |
794 | ||
795 | if (entity_is_task(se)) | |
796 | tsk = task_of(se); | |
797 | ||
41acab88 LDM |
798 | if (se->statistics.sleep_start) { |
799 | u64 delta = rq_of(cfs_rq)->clock - se->statistics.sleep_start; | |
bf0f6f24 IM |
800 | |
801 | if ((s64)delta < 0) | |
802 | delta = 0; | |
803 | ||
41acab88 LDM |
804 | if (unlikely(delta > se->statistics.sleep_max)) |
805 | se->statistics.sleep_max = delta; | |
bf0f6f24 | 806 | |
41acab88 LDM |
807 | se->statistics.sleep_start = 0; |
808 | se->statistics.sum_sleep_runtime += delta; | |
9745512c | 809 | |
768d0c27 | 810 | if (tsk) { |
e414314c | 811 | account_scheduler_latency(tsk, delta >> 10, 1); |
768d0c27 PZ |
812 | trace_sched_stat_sleep(tsk, delta); |
813 | } | |
bf0f6f24 | 814 | } |
41acab88 LDM |
815 | if (se->statistics.block_start) { |
816 | u64 delta = rq_of(cfs_rq)->clock - se->statistics.block_start; | |
bf0f6f24 IM |
817 | |
818 | if ((s64)delta < 0) | |
819 | delta = 0; | |
820 | ||
41acab88 LDM |
821 | if (unlikely(delta > se->statistics.block_max)) |
822 | se->statistics.block_max = delta; | |
bf0f6f24 | 823 | |
41acab88 LDM |
824 | se->statistics.block_start = 0; |
825 | se->statistics.sum_sleep_runtime += delta; | |
30084fbd | 826 | |
e414314c | 827 | if (tsk) { |
8f0dfc34 | 828 | if (tsk->in_iowait) { |
41acab88 LDM |
829 | se->statistics.iowait_sum += delta; |
830 | se->statistics.iowait_count++; | |
768d0c27 | 831 | trace_sched_stat_iowait(tsk, delta); |
8f0dfc34 AV |
832 | } |
833 | ||
e414314c PZ |
834 | /* |
835 | * Blocking time is in units of nanosecs, so shift by | |
836 | * 20 to get a milliseconds-range estimation of the | |
837 | * amount of time that the task spent sleeping: | |
838 | */ | |
839 | if (unlikely(prof_on == SLEEP_PROFILING)) { | |
840 | profile_hits(SLEEP_PROFILING, | |
841 | (void *)get_wchan(tsk), | |
842 | delta >> 20); | |
843 | } | |
844 | account_scheduler_latency(tsk, delta >> 10, 0); | |
30084fbd | 845 | } |
bf0f6f24 IM |
846 | } |
847 | #endif | |
848 | } | |
849 | ||
ddc97297 PZ |
850 | static void check_spread(struct cfs_rq *cfs_rq, struct sched_entity *se) |
851 | { | |
852 | #ifdef CONFIG_SCHED_DEBUG | |
853 | s64 d = se->vruntime - cfs_rq->min_vruntime; | |
854 | ||
855 | if (d < 0) | |
856 | d = -d; | |
857 | ||
858 | if (d > 3*sysctl_sched_latency) | |
859 | schedstat_inc(cfs_rq, nr_spread_over); | |
860 | #endif | |
861 | } | |
862 | ||
aeb73b04 PZ |
863 | static void |
864 | place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial) | |
865 | { | |
1af5f730 | 866 | u64 vruntime = cfs_rq->min_vruntime; |
94dfb5e7 | 867 | |
2cb8600e PZ |
868 | /* |
869 | * The 'current' period is already promised to the current tasks, | |
870 | * however the extra weight of the new task will slow them down a | |
871 | * little, place the new task so that it fits in the slot that | |
872 | * stays open at the end. | |
873 | */ | |
94dfb5e7 | 874 | if (initial && sched_feat(START_DEBIT)) |
f9c0b095 | 875 | vruntime += sched_vslice(cfs_rq, se); |
aeb73b04 | 876 | |
a2e7a7eb | 877 | /* sleeps up to a single latency don't count. */ |
5ca9880c | 878 | if (!initial) { |
a2e7a7eb | 879 | unsigned long thresh = sysctl_sched_latency; |
a7be37ac | 880 | |
a2e7a7eb MG |
881 | /* |
882 | * Halve their sleep time's effect, to allow | |
883 | * for a gentler effect of sleepers: | |
884 | */ | |
885 | if (sched_feat(GENTLE_FAIR_SLEEPERS)) | |
886 | thresh >>= 1; | |
51e0304c | 887 | |
a2e7a7eb | 888 | vruntime -= thresh; |
aeb73b04 PZ |
889 | } |
890 | ||
b5d9d734 MG |
891 | /* ensure we never gain time by being placed backwards. */ |
892 | vruntime = max_vruntime(se->vruntime, vruntime); | |
893 | ||
67e9fb2a | 894 | se->vruntime = vruntime; |
aeb73b04 PZ |
895 | } |
896 | ||
bf0f6f24 | 897 | static void |
88ec22d3 | 898 | enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) |
bf0f6f24 | 899 | { |
88ec22d3 PZ |
900 | /* |
901 | * Update the normalized vruntime before updating min_vruntime | |
902 | * through callig update_curr(). | |
903 | */ | |
371fd7e7 | 904 | if (!(flags & ENQUEUE_WAKEUP) || (flags & ENQUEUE_WAKING)) |
88ec22d3 PZ |
905 | se->vruntime += cfs_rq->min_vruntime; |
906 | ||
bf0f6f24 | 907 | /* |
a2a2d680 | 908 | * Update run-time statistics of the 'current'. |
bf0f6f24 | 909 | */ |
b7cc0896 | 910 | update_curr(cfs_rq); |
e33078ba | 911 | update_cfs_load(cfs_rq); |
f0d7442a | 912 | update_cfs_shares(cfs_rq, se->load.weight); |
a992241d | 913 | account_entity_enqueue(cfs_rq, se); |
bf0f6f24 | 914 | |
88ec22d3 | 915 | if (flags & ENQUEUE_WAKEUP) { |
aeb73b04 | 916 | place_entity(cfs_rq, se, 0); |
2396af69 | 917 | enqueue_sleeper(cfs_rq, se); |
e9acbff6 | 918 | } |
bf0f6f24 | 919 | |
d2417e5a | 920 | update_stats_enqueue(cfs_rq, se); |
ddc97297 | 921 | check_spread(cfs_rq, se); |
83b699ed SV |
922 | if (se != cfs_rq->curr) |
923 | __enqueue_entity(cfs_rq, se); | |
2069dd75 | 924 | se->on_rq = 1; |
3d4b47b4 PZ |
925 | |
926 | if (cfs_rq->nr_running == 1) | |
927 | list_add_leaf_cfs_rq(cfs_rq); | |
bf0f6f24 IM |
928 | } |
929 | ||
a571bbea | 930 | static void __clear_buddies(struct cfs_rq *cfs_rq, struct sched_entity *se) |
2002c695 | 931 | { |
de69a80b | 932 | if (!se || cfs_rq->last == se) |
2002c695 PZ |
933 | cfs_rq->last = NULL; |
934 | ||
de69a80b | 935 | if (!se || cfs_rq->next == se) |
2002c695 PZ |
936 | cfs_rq->next = NULL; |
937 | } | |
938 | ||
a571bbea PZ |
939 | static void clear_buddies(struct cfs_rq *cfs_rq, struct sched_entity *se) |
940 | { | |
941 | for_each_sched_entity(se) | |
942 | __clear_buddies(cfs_rq_of(se), se); | |
943 | } | |
944 | ||
bf0f6f24 | 945 | static void |
371fd7e7 | 946 | dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) |
bf0f6f24 | 947 | { |
a2a2d680 DA |
948 | /* |
949 | * Update run-time statistics of the 'current'. | |
950 | */ | |
951 | update_curr(cfs_rq); | |
952 | ||
19b6a2e3 | 953 | update_stats_dequeue(cfs_rq, se); |
371fd7e7 | 954 | if (flags & DEQUEUE_SLEEP) { |
67e9fb2a | 955 | #ifdef CONFIG_SCHEDSTATS |
bf0f6f24 IM |
956 | if (entity_is_task(se)) { |
957 | struct task_struct *tsk = task_of(se); | |
958 | ||
959 | if (tsk->state & TASK_INTERRUPTIBLE) | |
41acab88 | 960 | se->statistics.sleep_start = rq_of(cfs_rq)->clock; |
bf0f6f24 | 961 | if (tsk->state & TASK_UNINTERRUPTIBLE) |
41acab88 | 962 | se->statistics.block_start = rq_of(cfs_rq)->clock; |
bf0f6f24 | 963 | } |
db36cc7d | 964 | #endif |
67e9fb2a PZ |
965 | } |
966 | ||
2002c695 | 967 | clear_buddies(cfs_rq, se); |
4793241b | 968 | |
83b699ed | 969 | if (se != cfs_rq->curr) |
30cfdcfc | 970 | __dequeue_entity(cfs_rq, se); |
2069dd75 | 971 | se->on_rq = 0; |
e33078ba | 972 | update_cfs_load(cfs_rq); |
30cfdcfc | 973 | account_entity_dequeue(cfs_rq, se); |
1af5f730 | 974 | update_min_vruntime(cfs_rq); |
f0d7442a | 975 | update_cfs_shares(cfs_rq, 0); |
88ec22d3 PZ |
976 | |
977 | /* | |
978 | * Normalize the entity after updating the min_vruntime because the | |
979 | * update can refer to the ->curr item and we need to reflect this | |
980 | * movement in our normalized position. | |
981 | */ | |
371fd7e7 | 982 | if (!(flags & DEQUEUE_SLEEP)) |
88ec22d3 | 983 | se->vruntime -= cfs_rq->min_vruntime; |
bf0f6f24 IM |
984 | } |
985 | ||
986 | /* | |
987 | * Preempt the current task with a newly woken task if needed: | |
988 | */ | |
7c92e54f | 989 | static void |
2e09bf55 | 990 | check_preempt_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr) |
bf0f6f24 | 991 | { |
11697830 PZ |
992 | unsigned long ideal_runtime, delta_exec; |
993 | ||
6d0f0ebd | 994 | ideal_runtime = sched_slice(cfs_rq, curr); |
11697830 | 995 | delta_exec = curr->sum_exec_runtime - curr->prev_sum_exec_runtime; |
a9f3e2b5 | 996 | if (delta_exec > ideal_runtime) { |
bf0f6f24 | 997 | resched_task(rq_of(cfs_rq)->curr); |
a9f3e2b5 MG |
998 | /* |
999 | * The current task ran long enough, ensure it doesn't get | |
1000 | * re-elected due to buddy favours. | |
1001 | */ | |
1002 | clear_buddies(cfs_rq, curr); | |
f685ceac MG |
1003 | return; |
1004 | } | |
1005 | ||
1006 | /* | |
1007 | * Ensure that a task that missed wakeup preemption by a | |
1008 | * narrow margin doesn't have to wait for a full slice. | |
1009 | * This also mitigates buddy induced latencies under load. | |
1010 | */ | |
1011 | if (!sched_feat(WAKEUP_PREEMPT)) | |
1012 | return; | |
1013 | ||
1014 | if (delta_exec < sysctl_sched_min_granularity) | |
1015 | return; | |
1016 | ||
1017 | if (cfs_rq->nr_running > 1) { | |
1018 | struct sched_entity *se = __pick_next_entity(cfs_rq); | |
1019 | s64 delta = curr->vruntime - se->vruntime; | |
1020 | ||
1021 | if (delta > ideal_runtime) | |
1022 | resched_task(rq_of(cfs_rq)->curr); | |
a9f3e2b5 | 1023 | } |
bf0f6f24 IM |
1024 | } |
1025 | ||
83b699ed | 1026 | static void |
8494f412 | 1027 | set_next_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) |
bf0f6f24 | 1028 | { |
83b699ed SV |
1029 | /* 'current' is not kept within the tree. */ |
1030 | if (se->on_rq) { | |
1031 | /* | |
1032 | * Any task has to be enqueued before it get to execute on | |
1033 | * a CPU. So account for the time it spent waiting on the | |
1034 | * runqueue. | |
1035 | */ | |
1036 | update_stats_wait_end(cfs_rq, se); | |
1037 | __dequeue_entity(cfs_rq, se); | |
1038 | } | |
1039 | ||
79303e9e | 1040 | update_stats_curr_start(cfs_rq, se); |
429d43bc | 1041 | cfs_rq->curr = se; |
eba1ed4b IM |
1042 | #ifdef CONFIG_SCHEDSTATS |
1043 | /* | |
1044 | * Track our maximum slice length, if the CPU's load is at | |
1045 | * least twice that of our own weight (i.e. dont track it | |
1046 | * when there are only lesser-weight tasks around): | |
1047 | */ | |
495eca49 | 1048 | if (rq_of(cfs_rq)->load.weight >= 2*se->load.weight) { |
41acab88 | 1049 | se->statistics.slice_max = max(se->statistics.slice_max, |
eba1ed4b IM |
1050 | se->sum_exec_runtime - se->prev_sum_exec_runtime); |
1051 | } | |
1052 | #endif | |
4a55b450 | 1053 | se->prev_sum_exec_runtime = se->sum_exec_runtime; |
bf0f6f24 IM |
1054 | } |
1055 | ||
3f3a4904 PZ |
1056 | static int |
1057 | wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se); | |
1058 | ||
f4b6755f | 1059 | static struct sched_entity *pick_next_entity(struct cfs_rq *cfs_rq) |
aa2ac252 | 1060 | { |
f4b6755f | 1061 | struct sched_entity *se = __pick_next_entity(cfs_rq); |
f685ceac | 1062 | struct sched_entity *left = se; |
f4b6755f | 1063 | |
f685ceac MG |
1064 | if (cfs_rq->next && wakeup_preempt_entity(cfs_rq->next, left) < 1) |
1065 | se = cfs_rq->next; | |
aa2ac252 | 1066 | |
f685ceac MG |
1067 | /* |
1068 | * Prefer last buddy, try to return the CPU to a preempted task. | |
1069 | */ | |
1070 | if (cfs_rq->last && wakeup_preempt_entity(cfs_rq->last, left) < 1) | |
1071 | se = cfs_rq->last; | |
1072 | ||
1073 | clear_buddies(cfs_rq, se); | |
4793241b PZ |
1074 | |
1075 | return se; | |
aa2ac252 PZ |
1076 | } |
1077 | ||
ab6cde26 | 1078 | static void put_prev_entity(struct cfs_rq *cfs_rq, struct sched_entity *prev) |
bf0f6f24 IM |
1079 | { |
1080 | /* | |
1081 | * If still on the runqueue then deactivate_task() | |
1082 | * was not called and update_curr() has to be done: | |
1083 | */ | |
1084 | if (prev->on_rq) | |
b7cc0896 | 1085 | update_curr(cfs_rq); |
bf0f6f24 | 1086 | |
ddc97297 | 1087 | check_spread(cfs_rq, prev); |
30cfdcfc | 1088 | if (prev->on_rq) { |
5870db5b | 1089 | update_stats_wait_start(cfs_rq, prev); |
30cfdcfc DA |
1090 | /* Put 'current' back into the tree. */ |
1091 | __enqueue_entity(cfs_rq, prev); | |
1092 | } | |
429d43bc | 1093 | cfs_rq->curr = NULL; |
bf0f6f24 IM |
1094 | } |
1095 | ||
8f4d37ec PZ |
1096 | static void |
1097 | entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr, int queued) | |
bf0f6f24 | 1098 | { |
bf0f6f24 | 1099 | /* |
30cfdcfc | 1100 | * Update run-time statistics of the 'current'. |
bf0f6f24 | 1101 | */ |
30cfdcfc | 1102 | update_curr(cfs_rq); |
bf0f6f24 | 1103 | |
8f4d37ec PZ |
1104 | #ifdef CONFIG_SCHED_HRTICK |
1105 | /* | |
1106 | * queued ticks are scheduled to match the slice, so don't bother | |
1107 | * validating it and just reschedule. | |
1108 | */ | |
983ed7a6 HH |
1109 | if (queued) { |
1110 | resched_task(rq_of(cfs_rq)->curr); | |
1111 | return; | |
1112 | } | |
8f4d37ec PZ |
1113 | /* |
1114 | * don't let the period tick interfere with the hrtick preemption | |
1115 | */ | |
1116 | if (!sched_feat(DOUBLE_TICK) && | |
1117 | hrtimer_active(&rq_of(cfs_rq)->hrtick_timer)) | |
1118 | return; | |
1119 | #endif | |
1120 | ||
ce6c1311 | 1121 | if (cfs_rq->nr_running > 1 || !sched_feat(WAKEUP_PREEMPT)) |
2e09bf55 | 1122 | check_preempt_tick(cfs_rq, curr); |
bf0f6f24 IM |
1123 | } |
1124 | ||
1125 | /************************************************** | |
1126 | * CFS operations on tasks: | |
1127 | */ | |
1128 | ||
8f4d37ec PZ |
1129 | #ifdef CONFIG_SCHED_HRTICK |
1130 | static void hrtick_start_fair(struct rq *rq, struct task_struct *p) | |
1131 | { | |
8f4d37ec PZ |
1132 | struct sched_entity *se = &p->se; |
1133 | struct cfs_rq *cfs_rq = cfs_rq_of(se); | |
1134 | ||
1135 | WARN_ON(task_rq(p) != rq); | |
1136 | ||
1137 | if (hrtick_enabled(rq) && cfs_rq->nr_running > 1) { | |
1138 | u64 slice = sched_slice(cfs_rq, se); | |
1139 | u64 ran = se->sum_exec_runtime - se->prev_sum_exec_runtime; | |
1140 | s64 delta = slice - ran; | |
1141 | ||
1142 | if (delta < 0) { | |
1143 | if (rq->curr == p) | |
1144 | resched_task(p); | |
1145 | return; | |
1146 | } | |
1147 | ||
1148 | /* | |
1149 | * Don't schedule slices shorter than 10000ns, that just | |
1150 | * doesn't make sense. Rely on vruntime for fairness. | |
1151 | */ | |
31656519 | 1152 | if (rq->curr != p) |
157124c1 | 1153 | delta = max_t(s64, 10000LL, delta); |
8f4d37ec | 1154 | |
31656519 | 1155 | hrtick_start(rq, delta); |
8f4d37ec PZ |
1156 | } |
1157 | } | |
a4c2f00f PZ |
1158 | |
1159 | /* | |
1160 | * called from enqueue/dequeue and updates the hrtick when the | |
1161 | * current task is from our class and nr_running is low enough | |
1162 | * to matter. | |
1163 | */ | |
1164 | static void hrtick_update(struct rq *rq) | |
1165 | { | |
1166 | struct task_struct *curr = rq->curr; | |
1167 | ||
1168 | if (curr->sched_class != &fair_sched_class) | |
1169 | return; | |
1170 | ||
1171 | if (cfs_rq_of(&curr->se)->nr_running < sched_nr_latency) | |
1172 | hrtick_start_fair(rq, curr); | |
1173 | } | |
55e12e5e | 1174 | #else /* !CONFIG_SCHED_HRTICK */ |
8f4d37ec PZ |
1175 | static inline void |
1176 | hrtick_start_fair(struct rq *rq, struct task_struct *p) | |
1177 | { | |
1178 | } | |
a4c2f00f PZ |
1179 | |
1180 | static inline void hrtick_update(struct rq *rq) | |
1181 | { | |
1182 | } | |
8f4d37ec PZ |
1183 | #endif |
1184 | ||
bf0f6f24 IM |
1185 | /* |
1186 | * The enqueue_task method is called before nr_running is | |
1187 | * increased. Here we update the fair scheduling stats and | |
1188 | * then put the task into the rbtree: | |
1189 | */ | |
ea87bb78 | 1190 | static void |
371fd7e7 | 1191 | enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags) |
bf0f6f24 IM |
1192 | { |
1193 | struct cfs_rq *cfs_rq; | |
62fb1851 | 1194 | struct sched_entity *se = &p->se; |
bf0f6f24 IM |
1195 | |
1196 | for_each_sched_entity(se) { | |
62fb1851 | 1197 | if (se->on_rq) |
bf0f6f24 IM |
1198 | break; |
1199 | cfs_rq = cfs_rq_of(se); | |
88ec22d3 PZ |
1200 | enqueue_entity(cfs_rq, se, flags); |
1201 | flags = ENQUEUE_WAKEUP; | |
bf0f6f24 | 1202 | } |
8f4d37ec | 1203 | |
2069dd75 PZ |
1204 | for_each_sched_entity(se) { |
1205 | struct cfs_rq *cfs_rq = cfs_rq_of(se); | |
1206 | ||
e33078ba | 1207 | update_cfs_load(cfs_rq); |
f0d7442a | 1208 | update_cfs_shares(cfs_rq, 0); |
2069dd75 PZ |
1209 | } |
1210 | ||
a4c2f00f | 1211 | hrtick_update(rq); |
bf0f6f24 IM |
1212 | } |
1213 | ||
1214 | /* | |
1215 | * The dequeue_task method is called before nr_running is | |
1216 | * decreased. We remove the task from the rbtree and | |
1217 | * update the fair scheduling stats: | |
1218 | */ | |
371fd7e7 | 1219 | static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags) |
bf0f6f24 IM |
1220 | { |
1221 | struct cfs_rq *cfs_rq; | |
62fb1851 | 1222 | struct sched_entity *se = &p->se; |
bf0f6f24 IM |
1223 | |
1224 | for_each_sched_entity(se) { | |
1225 | cfs_rq = cfs_rq_of(se); | |
371fd7e7 | 1226 | dequeue_entity(cfs_rq, se, flags); |
2069dd75 | 1227 | |
bf0f6f24 | 1228 | /* Don't dequeue parent if it has other entities besides us */ |
62fb1851 | 1229 | if (cfs_rq->load.weight) |
bf0f6f24 | 1230 | break; |
371fd7e7 | 1231 | flags |= DEQUEUE_SLEEP; |
bf0f6f24 | 1232 | } |
8f4d37ec | 1233 | |
2069dd75 PZ |
1234 | for_each_sched_entity(se) { |
1235 | struct cfs_rq *cfs_rq = cfs_rq_of(se); | |
1236 | ||
e33078ba | 1237 | update_cfs_load(cfs_rq); |
f0d7442a | 1238 | update_cfs_shares(cfs_rq, 0); |
2069dd75 PZ |
1239 | } |
1240 | ||
a4c2f00f | 1241 | hrtick_update(rq); |
bf0f6f24 IM |
1242 | } |
1243 | ||
1244 | /* | |
1799e35d IM |
1245 | * sched_yield() support is very simple - we dequeue and enqueue. |
1246 | * | |
1247 | * If compat_yield is turned on then we requeue to the end of the tree. | |
bf0f6f24 | 1248 | */ |
4530d7ab | 1249 | static void yield_task_fair(struct rq *rq) |
bf0f6f24 | 1250 | { |
db292ca3 IM |
1251 | struct task_struct *curr = rq->curr; |
1252 | struct cfs_rq *cfs_rq = task_cfs_rq(curr); | |
1253 | struct sched_entity *rightmost, *se = &curr->se; | |
bf0f6f24 IM |
1254 | |
1255 | /* | |
1799e35d IM |
1256 | * Are we the only task in the tree? |
1257 | */ | |
1258 | if (unlikely(cfs_rq->nr_running == 1)) | |
1259 | return; | |
1260 | ||
2002c695 PZ |
1261 | clear_buddies(cfs_rq, se); |
1262 | ||
db292ca3 | 1263 | if (likely(!sysctl_sched_compat_yield) && curr->policy != SCHED_BATCH) { |
3e51f33f | 1264 | update_rq_clock(rq); |
1799e35d | 1265 | /* |
a2a2d680 | 1266 | * Update run-time statistics of the 'current'. |
1799e35d | 1267 | */ |
2b1e315d | 1268 | update_curr(cfs_rq); |
1799e35d IM |
1269 | |
1270 | return; | |
1271 | } | |
1272 | /* | |
1273 | * Find the rightmost entry in the rbtree: | |
bf0f6f24 | 1274 | */ |
2b1e315d | 1275 | rightmost = __pick_last_entity(cfs_rq); |
1799e35d IM |
1276 | /* |
1277 | * Already in the rightmost position? | |
1278 | */ | |
54fdc581 | 1279 | if (unlikely(!rightmost || entity_before(rightmost, se))) |
1799e35d IM |
1280 | return; |
1281 | ||
1282 | /* | |
1283 | * Minimally necessary key value to be last in the tree: | |
2b1e315d DA |
1284 | * Upon rescheduling, sched_class::put_prev_task() will place |
1285 | * 'current' within the tree based on its new key value. | |
1799e35d | 1286 | */ |
30cfdcfc | 1287 | se->vruntime = rightmost->vruntime + 1; |
bf0f6f24 IM |
1288 | } |
1289 | ||
e7693a36 | 1290 | #ifdef CONFIG_SMP |
098fb9db | 1291 | |
88ec22d3 PZ |
1292 | static void task_waking_fair(struct rq *rq, struct task_struct *p) |
1293 | { | |
1294 | struct sched_entity *se = &p->se; | |
1295 | struct cfs_rq *cfs_rq = cfs_rq_of(se); | |
1296 | ||
1297 | se->vruntime -= cfs_rq->min_vruntime; | |
1298 | } | |
1299 | ||
bb3469ac | 1300 | #ifdef CONFIG_FAIR_GROUP_SCHED |
f5bfb7d9 PZ |
1301 | /* |
1302 | * effective_load() calculates the load change as seen from the root_task_group | |
1303 | * | |
1304 | * Adding load to a group doesn't make a group heavier, but can cause movement | |
1305 | * of group shares between cpus. Assuming the shares were perfectly aligned one | |
1306 | * can calculate the shift in shares. | |
f5bfb7d9 | 1307 | */ |
2069dd75 | 1308 | static long effective_load(struct task_group *tg, int cpu, long wl, long wg) |
bb3469ac | 1309 | { |
4be9daaa | 1310 | struct sched_entity *se = tg->se[cpu]; |
f1d239f7 PZ |
1311 | |
1312 | if (!tg->parent) | |
1313 | return wl; | |
1314 | ||
4be9daaa | 1315 | for_each_sched_entity(se) { |
cb5ef42a | 1316 | long S, rw, s, a, b; |
4be9daaa PZ |
1317 | |
1318 | S = se->my_q->tg->shares; | |
2069dd75 PZ |
1319 | s = se->load.weight; |
1320 | rw = se->my_q->load.weight; | |
bb3469ac | 1321 | |
cb5ef42a PZ |
1322 | a = S*(rw + wl); |
1323 | b = S*rw + s*wg; | |
4be9daaa | 1324 | |
940959e9 PZ |
1325 | wl = s*(a-b); |
1326 | ||
1327 | if (likely(b)) | |
1328 | wl /= b; | |
1329 | ||
83378269 PZ |
1330 | /* |
1331 | * Assume the group is already running and will | |
1332 | * thus already be accounted for in the weight. | |
1333 | * | |
1334 | * That is, moving shares between CPUs, does not | |
1335 | * alter the group weight. | |
1336 | */ | |
4be9daaa | 1337 | wg = 0; |
4be9daaa | 1338 | } |
bb3469ac | 1339 | |
4be9daaa | 1340 | return wl; |
bb3469ac | 1341 | } |
4be9daaa | 1342 | |
bb3469ac | 1343 | #else |
4be9daaa | 1344 | |
83378269 PZ |
1345 | static inline unsigned long effective_load(struct task_group *tg, int cpu, |
1346 | unsigned long wl, unsigned long wg) | |
4be9daaa | 1347 | { |
83378269 | 1348 | return wl; |
bb3469ac | 1349 | } |
4be9daaa | 1350 | |
bb3469ac PZ |
1351 | #endif |
1352 | ||
c88d5910 | 1353 | static int wake_affine(struct sched_domain *sd, struct task_struct *p, int sync) |
098fb9db | 1354 | { |
c88d5910 PZ |
1355 | unsigned long this_load, load; |
1356 | int idx, this_cpu, prev_cpu; | |
098fb9db | 1357 | unsigned long tl_per_task; |
c88d5910 | 1358 | struct task_group *tg; |
83378269 | 1359 | unsigned long weight; |
b3137bc8 | 1360 | int balanced; |
098fb9db | 1361 | |
c88d5910 PZ |
1362 | idx = sd->wake_idx; |
1363 | this_cpu = smp_processor_id(); | |
1364 | prev_cpu = task_cpu(p); | |
1365 | load = source_load(prev_cpu, idx); | |
1366 | this_load = target_load(this_cpu, idx); | |
098fb9db | 1367 | |
b3137bc8 MG |
1368 | /* |
1369 | * If sync wakeup then subtract the (maximum possible) | |
1370 | * effect of the currently running task from the load | |
1371 | * of the current CPU: | |
1372 | */ | |
f3b577de | 1373 | rcu_read_lock(); |
83378269 PZ |
1374 | if (sync) { |
1375 | tg = task_group(current); | |
1376 | weight = current->se.load.weight; | |
1377 | ||
c88d5910 | 1378 | this_load += effective_load(tg, this_cpu, -weight, -weight); |
83378269 PZ |
1379 | load += effective_load(tg, prev_cpu, 0, -weight); |
1380 | } | |
b3137bc8 | 1381 | |
83378269 PZ |
1382 | tg = task_group(p); |
1383 | weight = p->se.load.weight; | |
b3137bc8 | 1384 | |
71a29aa7 PZ |
1385 | /* |
1386 | * In low-load situations, where prev_cpu is idle and this_cpu is idle | |
c88d5910 PZ |
1387 | * due to the sync cause above having dropped this_load to 0, we'll |
1388 | * always have an imbalance, but there's really nothing you can do | |
1389 | * about that, so that's good too. | |
71a29aa7 PZ |
1390 | * |
1391 | * Otherwise check if either cpus are near enough in load to allow this | |
1392 | * task to be woken on this_cpu. | |
1393 | */ | |
e51fd5e2 PZ |
1394 | if (this_load) { |
1395 | unsigned long this_eff_load, prev_eff_load; | |
1396 | ||
1397 | this_eff_load = 100; | |
1398 | this_eff_load *= power_of(prev_cpu); | |
1399 | this_eff_load *= this_load + | |
1400 | effective_load(tg, this_cpu, weight, weight); | |
1401 | ||
1402 | prev_eff_load = 100 + (sd->imbalance_pct - 100) / 2; | |
1403 | prev_eff_load *= power_of(this_cpu); | |
1404 | prev_eff_load *= load + effective_load(tg, prev_cpu, 0, weight); | |
1405 | ||
1406 | balanced = this_eff_load <= prev_eff_load; | |
1407 | } else | |
1408 | balanced = true; | |
f3b577de | 1409 | rcu_read_unlock(); |
b3137bc8 | 1410 | |
098fb9db | 1411 | /* |
4ae7d5ce IM |
1412 | * If the currently running task will sleep within |
1413 | * a reasonable amount of time then attract this newly | |
1414 | * woken task: | |
098fb9db | 1415 | */ |
2fb7635c PZ |
1416 | if (sync && balanced) |
1417 | return 1; | |
098fb9db | 1418 | |
41acab88 | 1419 | schedstat_inc(p, se.statistics.nr_wakeups_affine_attempts); |
098fb9db IM |
1420 | tl_per_task = cpu_avg_load_per_task(this_cpu); |
1421 | ||
c88d5910 PZ |
1422 | if (balanced || |
1423 | (this_load <= load && | |
1424 | this_load + target_load(prev_cpu, idx) <= tl_per_task)) { | |
098fb9db IM |
1425 | /* |
1426 | * This domain has SD_WAKE_AFFINE and | |
1427 | * p is cache cold in this domain, and | |
1428 | * there is no bad imbalance. | |
1429 | */ | |
c88d5910 | 1430 | schedstat_inc(sd, ttwu_move_affine); |
41acab88 | 1431 | schedstat_inc(p, se.statistics.nr_wakeups_affine); |
098fb9db IM |
1432 | |
1433 | return 1; | |
1434 | } | |
1435 | return 0; | |
1436 | } | |
1437 | ||
aaee1203 PZ |
1438 | /* |
1439 | * find_idlest_group finds and returns the least busy CPU group within the | |
1440 | * domain. | |
1441 | */ | |
1442 | static struct sched_group * | |
78e7ed53 | 1443 | find_idlest_group(struct sched_domain *sd, struct task_struct *p, |
5158f4e4 | 1444 | int this_cpu, int load_idx) |
e7693a36 | 1445 | { |
b3bd3de6 | 1446 | struct sched_group *idlest = NULL, *group = sd->groups; |
aaee1203 | 1447 | unsigned long min_load = ULONG_MAX, this_load = 0; |
aaee1203 | 1448 | int imbalance = 100 + (sd->imbalance_pct-100)/2; |
e7693a36 | 1449 | |
aaee1203 PZ |
1450 | do { |
1451 | unsigned long load, avg_load; | |
1452 | int local_group; | |
1453 | int i; | |
e7693a36 | 1454 | |
aaee1203 PZ |
1455 | /* Skip over this group if it has no CPUs allowed */ |
1456 | if (!cpumask_intersects(sched_group_cpus(group), | |
1457 | &p->cpus_allowed)) | |
1458 | continue; | |
1459 | ||
1460 | local_group = cpumask_test_cpu(this_cpu, | |
1461 | sched_group_cpus(group)); | |
1462 | ||
1463 | /* Tally up the load of all CPUs in the group */ | |
1464 | avg_load = 0; | |
1465 | ||
1466 | for_each_cpu(i, sched_group_cpus(group)) { | |
1467 | /* Bias balancing toward cpus of our domain */ | |
1468 | if (local_group) | |
1469 | load = source_load(i, load_idx); | |
1470 | else | |
1471 | load = target_load(i, load_idx); | |
1472 | ||
1473 | avg_load += load; | |
1474 | } | |
1475 | ||
1476 | /* Adjust by relative CPU power of the group */ | |
1477 | avg_load = (avg_load * SCHED_LOAD_SCALE) / group->cpu_power; | |
1478 | ||
1479 | if (local_group) { | |
1480 | this_load = avg_load; | |
aaee1203 PZ |
1481 | } else if (avg_load < min_load) { |
1482 | min_load = avg_load; | |
1483 | idlest = group; | |
1484 | } | |
1485 | } while (group = group->next, group != sd->groups); | |
1486 | ||
1487 | if (!idlest || 100*this_load < imbalance*min_load) | |
1488 | return NULL; | |
1489 | return idlest; | |
1490 | } | |
1491 | ||
1492 | /* | |
1493 | * find_idlest_cpu - find the idlest cpu among the cpus in group. | |
1494 | */ | |
1495 | static int | |
1496 | find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu) | |
1497 | { | |
1498 | unsigned long load, min_load = ULONG_MAX; | |
1499 | int idlest = -1; | |
1500 | int i; | |
1501 | ||
1502 | /* Traverse only the allowed CPUs */ | |
1503 | for_each_cpu_and(i, sched_group_cpus(group), &p->cpus_allowed) { | |
1504 | load = weighted_cpuload(i); | |
1505 | ||
1506 | if (load < min_load || (load == min_load && i == this_cpu)) { | |
1507 | min_load = load; | |
1508 | idlest = i; | |
e7693a36 GH |
1509 | } |
1510 | } | |
1511 | ||
aaee1203 PZ |
1512 | return idlest; |
1513 | } | |
e7693a36 | 1514 | |
a50bde51 PZ |
1515 | /* |
1516 | * Try and locate an idle CPU in the sched_domain. | |
1517 | */ | |
99bd5e2f | 1518 | static int select_idle_sibling(struct task_struct *p, int target) |
a50bde51 PZ |
1519 | { |
1520 | int cpu = smp_processor_id(); | |
1521 | int prev_cpu = task_cpu(p); | |
99bd5e2f | 1522 | struct sched_domain *sd; |
a50bde51 PZ |
1523 | int i; |
1524 | ||
1525 | /* | |
99bd5e2f SS |
1526 | * If the task is going to be woken-up on this cpu and if it is |
1527 | * already idle, then it is the right target. | |
a50bde51 | 1528 | */ |
99bd5e2f SS |
1529 | if (target == cpu && idle_cpu(cpu)) |
1530 | return cpu; | |
1531 | ||
1532 | /* | |
1533 | * If the task is going to be woken-up on the cpu where it previously | |
1534 | * ran and if it is currently idle, then it the right target. | |
1535 | */ | |
1536 | if (target == prev_cpu && idle_cpu(prev_cpu)) | |
fe3bcfe1 | 1537 | return prev_cpu; |
a50bde51 PZ |
1538 | |
1539 | /* | |
99bd5e2f | 1540 | * Otherwise, iterate the domains and find an elegible idle cpu. |
a50bde51 | 1541 | */ |
99bd5e2f SS |
1542 | for_each_domain(target, sd) { |
1543 | if (!(sd->flags & SD_SHARE_PKG_RESOURCES)) | |
fe3bcfe1 | 1544 | break; |
99bd5e2f SS |
1545 | |
1546 | for_each_cpu_and(i, sched_domain_span(sd), &p->cpus_allowed) { | |
1547 | if (idle_cpu(i)) { | |
1548 | target = i; | |
1549 | break; | |
1550 | } | |
a50bde51 | 1551 | } |
99bd5e2f SS |
1552 | |
1553 | /* | |
1554 | * Lets stop looking for an idle sibling when we reached | |
1555 | * the domain that spans the current cpu and prev_cpu. | |
1556 | */ | |
1557 | if (cpumask_test_cpu(cpu, sched_domain_span(sd)) && | |
1558 | cpumask_test_cpu(prev_cpu, sched_domain_span(sd))) | |
1559 | break; | |
a50bde51 PZ |
1560 | } |
1561 | ||
1562 | return target; | |
1563 | } | |
1564 | ||
aaee1203 PZ |
1565 | /* |
1566 | * sched_balance_self: balance the current task (running on cpu) in domains | |
1567 | * that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and | |
1568 | * SD_BALANCE_EXEC. | |
1569 | * | |
1570 | * Balance, ie. select the least loaded group. | |
1571 | * | |
1572 | * Returns the target CPU number, or the same CPU if no balancing is needed. | |
1573 | * | |
1574 | * preempt must be disabled. | |
1575 | */ | |
0017d735 PZ |
1576 | static int |
1577 | select_task_rq_fair(struct rq *rq, struct task_struct *p, int sd_flag, int wake_flags) | |
aaee1203 | 1578 | { |
29cd8bae | 1579 | struct sched_domain *tmp, *affine_sd = NULL, *sd = NULL; |
c88d5910 PZ |
1580 | int cpu = smp_processor_id(); |
1581 | int prev_cpu = task_cpu(p); | |
1582 | int new_cpu = cpu; | |
99bd5e2f | 1583 | int want_affine = 0; |
29cd8bae | 1584 | int want_sd = 1; |
5158f4e4 | 1585 | int sync = wake_flags & WF_SYNC; |
c88d5910 | 1586 | |
0763a660 | 1587 | if (sd_flag & SD_BALANCE_WAKE) { |
beac4c7e | 1588 | if (cpumask_test_cpu(cpu, &p->cpus_allowed)) |
c88d5910 PZ |
1589 | want_affine = 1; |
1590 | new_cpu = prev_cpu; | |
1591 | } | |
aaee1203 PZ |
1592 | |
1593 | for_each_domain(cpu, tmp) { | |
e4f42888 PZ |
1594 | if (!(tmp->flags & SD_LOAD_BALANCE)) |
1595 | continue; | |
1596 | ||
aaee1203 | 1597 | /* |
ae154be1 PZ |
1598 | * If power savings logic is enabled for a domain, see if we |
1599 | * are not overloaded, if so, don't balance wider. | |
aaee1203 | 1600 | */ |
59abf026 | 1601 | if (tmp->flags & (SD_POWERSAVINGS_BALANCE|SD_PREFER_LOCAL)) { |
ae154be1 PZ |
1602 | unsigned long power = 0; |
1603 | unsigned long nr_running = 0; | |
1604 | unsigned long capacity; | |
1605 | int i; | |
1606 | ||
1607 | for_each_cpu(i, sched_domain_span(tmp)) { | |
1608 | power += power_of(i); | |
1609 | nr_running += cpu_rq(i)->cfs.nr_running; | |
1610 | } | |
1611 | ||
1612 | capacity = DIV_ROUND_CLOSEST(power, SCHED_LOAD_SCALE); | |
1613 | ||
59abf026 PZ |
1614 | if (tmp->flags & SD_POWERSAVINGS_BALANCE) |
1615 | nr_running /= 2; | |
1616 | ||
1617 | if (nr_running < capacity) | |
29cd8bae | 1618 | want_sd = 0; |
ae154be1 | 1619 | } |
aaee1203 | 1620 | |
fe3bcfe1 | 1621 | /* |
99bd5e2f SS |
1622 | * If both cpu and prev_cpu are part of this domain, |
1623 | * cpu is a valid SD_WAKE_AFFINE target. | |
fe3bcfe1 | 1624 | */ |
99bd5e2f SS |
1625 | if (want_affine && (tmp->flags & SD_WAKE_AFFINE) && |
1626 | cpumask_test_cpu(prev_cpu, sched_domain_span(tmp))) { | |
1627 | affine_sd = tmp; | |
1628 | want_affine = 0; | |
c88d5910 PZ |
1629 | } |
1630 | ||
29cd8bae PZ |
1631 | if (!want_sd && !want_affine) |
1632 | break; | |
1633 | ||
0763a660 | 1634 | if (!(tmp->flags & sd_flag)) |
c88d5910 PZ |
1635 | continue; |
1636 | ||
29cd8bae PZ |
1637 | if (want_sd) |
1638 | sd = tmp; | |
1639 | } | |
1640 | ||
8b911acd | 1641 | if (affine_sd) { |
99bd5e2f SS |
1642 | if (cpu == prev_cpu || wake_affine(affine_sd, p, sync)) |
1643 | return select_idle_sibling(p, cpu); | |
1644 | else | |
1645 | return select_idle_sibling(p, prev_cpu); | |
8b911acd | 1646 | } |
e7693a36 | 1647 | |
aaee1203 | 1648 | while (sd) { |
5158f4e4 | 1649 | int load_idx = sd->forkexec_idx; |
aaee1203 | 1650 | struct sched_group *group; |
c88d5910 | 1651 | int weight; |
098fb9db | 1652 | |
0763a660 | 1653 | if (!(sd->flags & sd_flag)) { |
aaee1203 PZ |
1654 | sd = sd->child; |
1655 | continue; | |
1656 | } | |
098fb9db | 1657 | |
5158f4e4 PZ |
1658 | if (sd_flag & SD_BALANCE_WAKE) |
1659 | load_idx = sd->wake_idx; | |
098fb9db | 1660 | |
5158f4e4 | 1661 | group = find_idlest_group(sd, p, cpu, load_idx); |
aaee1203 PZ |
1662 | if (!group) { |
1663 | sd = sd->child; | |
1664 | continue; | |
1665 | } | |
4ae7d5ce | 1666 | |
d7c33c49 | 1667 | new_cpu = find_idlest_cpu(group, p, cpu); |
aaee1203 PZ |
1668 | if (new_cpu == -1 || new_cpu == cpu) { |
1669 | /* Now try balancing at a lower domain level of cpu */ | |
1670 | sd = sd->child; | |
1671 | continue; | |
e7693a36 | 1672 | } |
aaee1203 PZ |
1673 | |
1674 | /* Now try balancing at a lower domain level of new_cpu */ | |
1675 | cpu = new_cpu; | |
669c55e9 | 1676 | weight = sd->span_weight; |
aaee1203 PZ |
1677 | sd = NULL; |
1678 | for_each_domain(cpu, tmp) { | |
669c55e9 | 1679 | if (weight <= tmp->span_weight) |
aaee1203 | 1680 | break; |
0763a660 | 1681 | if (tmp->flags & sd_flag) |
aaee1203 PZ |
1682 | sd = tmp; |
1683 | } | |
1684 | /* while loop will break here if sd == NULL */ | |
e7693a36 GH |
1685 | } |
1686 | ||
c88d5910 | 1687 | return new_cpu; |
e7693a36 GH |
1688 | } |
1689 | #endif /* CONFIG_SMP */ | |
1690 | ||
e52fb7c0 PZ |
1691 | static unsigned long |
1692 | wakeup_gran(struct sched_entity *curr, struct sched_entity *se) | |
0bbd3336 PZ |
1693 | { |
1694 | unsigned long gran = sysctl_sched_wakeup_granularity; | |
1695 | ||
1696 | /* | |
e52fb7c0 PZ |
1697 | * Since its curr running now, convert the gran from real-time |
1698 | * to virtual-time in his units. | |
13814d42 MG |
1699 | * |
1700 | * By using 'se' instead of 'curr' we penalize light tasks, so | |
1701 | * they get preempted easier. That is, if 'se' < 'curr' then | |
1702 | * the resulting gran will be larger, therefore penalizing the | |
1703 | * lighter, if otoh 'se' > 'curr' then the resulting gran will | |
1704 | * be smaller, again penalizing the lighter task. | |
1705 | * | |
1706 | * This is especially important for buddies when the leftmost | |
1707 | * task is higher priority than the buddy. | |
0bbd3336 | 1708 | */ |
13814d42 MG |
1709 | if (unlikely(se->load.weight != NICE_0_LOAD)) |
1710 | gran = calc_delta_fair(gran, se); | |
0bbd3336 PZ |
1711 | |
1712 | return gran; | |
1713 | } | |
1714 | ||
464b7527 PZ |
1715 | /* |
1716 | * Should 'se' preempt 'curr'. | |
1717 | * | |
1718 | * |s1 | |
1719 | * |s2 | |
1720 | * |s3 | |
1721 | * g | |
1722 | * |<--->|c | |
1723 | * | |
1724 | * w(c, s1) = -1 | |
1725 | * w(c, s2) = 0 | |
1726 | * w(c, s3) = 1 | |
1727 | * | |
1728 | */ | |
1729 | static int | |
1730 | wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se) | |
1731 | { | |
1732 | s64 gran, vdiff = curr->vruntime - se->vruntime; | |
1733 | ||
1734 | if (vdiff <= 0) | |
1735 | return -1; | |
1736 | ||
e52fb7c0 | 1737 | gran = wakeup_gran(curr, se); |
464b7527 PZ |
1738 | if (vdiff > gran) |
1739 | return 1; | |
1740 | ||
1741 | return 0; | |
1742 | } | |
1743 | ||
02479099 PZ |
1744 | static void set_last_buddy(struct sched_entity *se) |
1745 | { | |
6bc912b7 PZ |
1746 | if (likely(task_of(se)->policy != SCHED_IDLE)) { |
1747 | for_each_sched_entity(se) | |
1748 | cfs_rq_of(se)->last = se; | |
1749 | } | |
02479099 PZ |
1750 | } |
1751 | ||
1752 | static void set_next_buddy(struct sched_entity *se) | |
1753 | { | |
6bc912b7 PZ |
1754 | if (likely(task_of(se)->policy != SCHED_IDLE)) { |
1755 | for_each_sched_entity(se) | |
1756 | cfs_rq_of(se)->next = se; | |
1757 | } | |
02479099 PZ |
1758 | } |
1759 | ||
bf0f6f24 IM |
1760 | /* |
1761 | * Preempt the current task with a newly woken task if needed: | |
1762 | */ | |
5a9b86f6 | 1763 | static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_flags) |
bf0f6f24 IM |
1764 | { |
1765 | struct task_struct *curr = rq->curr; | |
8651a86c | 1766 | struct sched_entity *se = &curr->se, *pse = &p->se; |
03e89e45 | 1767 | struct cfs_rq *cfs_rq = task_cfs_rq(curr); |
f685ceac | 1768 | int scale = cfs_rq->nr_running >= sched_nr_latency; |
bf0f6f24 | 1769 | |
3a7e73a2 PZ |
1770 | if (unlikely(rt_prio(p->prio))) |
1771 | goto preempt; | |
aa2ac252 | 1772 | |
d95f98d0 PZ |
1773 | if (unlikely(p->sched_class != &fair_sched_class)) |
1774 | return; | |
1775 | ||
4ae7d5ce IM |
1776 | if (unlikely(se == pse)) |
1777 | return; | |
1778 | ||
f685ceac | 1779 | if (sched_feat(NEXT_BUDDY) && scale && !(wake_flags & WF_FORK)) |
3cb63d52 | 1780 | set_next_buddy(pse); |
57fdc26d | 1781 | |
aec0a514 BR |
1782 | /* |
1783 | * We can come here with TIF_NEED_RESCHED already set from new task | |
1784 | * wake up path. | |
1785 | */ | |
1786 | if (test_tsk_need_resched(curr)) | |
1787 | return; | |
1788 | ||
91c234b4 | 1789 | /* |
6bc912b7 | 1790 | * Batch and idle tasks do not preempt (their preemption is driven by |
91c234b4 IM |
1791 | * the tick): |
1792 | */ | |
6bc912b7 | 1793 | if (unlikely(p->policy != SCHED_NORMAL)) |
91c234b4 | 1794 | return; |
bf0f6f24 | 1795 | |
6bc912b7 | 1796 | /* Idle tasks are by definition preempted by everybody. */ |
3a7e73a2 PZ |
1797 | if (unlikely(curr->policy == SCHED_IDLE)) |
1798 | goto preempt; | |
bf0f6f24 | 1799 | |
ad4b78bb PZ |
1800 | if (!sched_feat(WAKEUP_PREEMPT)) |
1801 | return; | |
1802 | ||
3a7e73a2 | 1803 | update_curr(cfs_rq); |
464b7527 | 1804 | find_matching_se(&se, &pse); |
002f128b | 1805 | BUG_ON(!pse); |
3a7e73a2 PZ |
1806 | if (wakeup_preempt_entity(se, pse) == 1) |
1807 | goto preempt; | |
464b7527 | 1808 | |
3a7e73a2 | 1809 | return; |
a65ac745 | 1810 | |
3a7e73a2 PZ |
1811 | preempt: |
1812 | resched_task(curr); | |
1813 | /* | |
1814 | * Only set the backward buddy when the current task is still | |
1815 | * on the rq. This can happen when a wakeup gets interleaved | |
1816 | * with schedule on the ->pre_schedule() or idle_balance() | |
1817 | * point, either of which can * drop the rq lock. | |
1818 | * | |
1819 | * Also, during early boot the idle thread is in the fair class, | |
1820 | * for obvious reasons its a bad idea to schedule back to it. | |
1821 | */ | |
1822 | if (unlikely(!se->on_rq || curr == rq->idle)) | |
1823 | return; | |
1824 | ||
1825 | if (sched_feat(LAST_BUDDY) && scale && entity_is_task(se)) | |
1826 | set_last_buddy(se); | |
bf0f6f24 IM |
1827 | } |
1828 | ||
fb8d4724 | 1829 | static struct task_struct *pick_next_task_fair(struct rq *rq) |
bf0f6f24 | 1830 | { |
8f4d37ec | 1831 | struct task_struct *p; |
bf0f6f24 IM |
1832 | struct cfs_rq *cfs_rq = &rq->cfs; |
1833 | struct sched_entity *se; | |
1834 | ||
36ace27e | 1835 | if (!cfs_rq->nr_running) |
bf0f6f24 IM |
1836 | return NULL; |
1837 | ||
1838 | do { | |
9948f4b2 | 1839 | se = pick_next_entity(cfs_rq); |
f4b6755f | 1840 | set_next_entity(cfs_rq, se); |
bf0f6f24 IM |
1841 | cfs_rq = group_cfs_rq(se); |
1842 | } while (cfs_rq); | |
1843 | ||
8f4d37ec PZ |
1844 | p = task_of(se); |
1845 | hrtick_start_fair(rq, p); | |
1846 | ||
1847 | return p; | |
bf0f6f24 IM |
1848 | } |
1849 | ||
1850 | /* | |
1851 | * Account for a descheduled task: | |
1852 | */ | |
31ee529c | 1853 | static void put_prev_task_fair(struct rq *rq, struct task_struct *prev) |
bf0f6f24 IM |
1854 | { |
1855 | struct sched_entity *se = &prev->se; | |
1856 | struct cfs_rq *cfs_rq; | |
1857 | ||
1858 | for_each_sched_entity(se) { | |
1859 | cfs_rq = cfs_rq_of(se); | |
ab6cde26 | 1860 | put_prev_entity(cfs_rq, se); |
bf0f6f24 IM |
1861 | } |
1862 | } | |
1863 | ||
681f3e68 | 1864 | #ifdef CONFIG_SMP |
bf0f6f24 IM |
1865 | /************************************************** |
1866 | * Fair scheduling class load-balancing methods: | |
1867 | */ | |
1868 | ||
1e3c88bd PZ |
1869 | /* |
1870 | * pull_task - move a task from a remote runqueue to the local runqueue. | |
1871 | * Both runqueues must be locked. | |
1872 | */ | |
1873 | static void pull_task(struct rq *src_rq, struct task_struct *p, | |
1874 | struct rq *this_rq, int this_cpu) | |
1875 | { | |
1876 | deactivate_task(src_rq, p, 0); | |
1877 | set_task_cpu(p, this_cpu); | |
1878 | activate_task(this_rq, p, 0); | |
1879 | check_preempt_curr(this_rq, p, 0); | |
fab47622 NR |
1880 | |
1881 | /* re-arm NEWIDLE balancing when moving tasks */ | |
1882 | src_rq->avg_idle = this_rq->avg_idle = 2*sysctl_sched_migration_cost; | |
1883 | this_rq->idle_stamp = 0; | |
1e3c88bd PZ |
1884 | } |
1885 | ||
1886 | /* | |
1887 | * can_migrate_task - may task p from runqueue rq be migrated to this_cpu? | |
1888 | */ | |
1889 | static | |
1890 | int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu, | |
1891 | struct sched_domain *sd, enum cpu_idle_type idle, | |
1892 | int *all_pinned) | |
1893 | { | |
1894 | int tsk_cache_hot = 0; | |
1895 | /* | |
1896 | * We do not migrate tasks that are: | |
1897 | * 1) running (obviously), or | |
1898 | * 2) cannot be migrated to this CPU due to cpus_allowed, or | |
1899 | * 3) are cache-hot on their current CPU. | |
1900 | */ | |
1901 | if (!cpumask_test_cpu(this_cpu, &p->cpus_allowed)) { | |
41acab88 | 1902 | schedstat_inc(p, se.statistics.nr_failed_migrations_affine); |
1e3c88bd PZ |
1903 | return 0; |
1904 | } | |
1905 | *all_pinned = 0; | |
1906 | ||
1907 | if (task_running(rq, p)) { | |
41acab88 | 1908 | schedstat_inc(p, se.statistics.nr_failed_migrations_running); |
1e3c88bd PZ |
1909 | return 0; |
1910 | } | |
1911 | ||
1912 | /* | |
1913 | * Aggressive migration if: | |
1914 | * 1) task is cache cold, or | |
1915 | * 2) too many balance attempts have failed. | |
1916 | */ | |
1917 | ||
305e6835 | 1918 | tsk_cache_hot = task_hot(p, rq->clock_task, sd); |
1e3c88bd PZ |
1919 | if (!tsk_cache_hot || |
1920 | sd->nr_balance_failed > sd->cache_nice_tries) { | |
1921 | #ifdef CONFIG_SCHEDSTATS | |
1922 | if (tsk_cache_hot) { | |
1923 | schedstat_inc(sd, lb_hot_gained[idle]); | |
41acab88 | 1924 | schedstat_inc(p, se.statistics.nr_forced_migrations); |
1e3c88bd PZ |
1925 | } |
1926 | #endif | |
1927 | return 1; | |
1928 | } | |
1929 | ||
1930 | if (tsk_cache_hot) { | |
41acab88 | 1931 | schedstat_inc(p, se.statistics.nr_failed_migrations_hot); |
1e3c88bd PZ |
1932 | return 0; |
1933 | } | |
1934 | return 1; | |
1935 | } | |
1936 | ||
897c395f PZ |
1937 | /* |
1938 | * move_one_task tries to move exactly one task from busiest to this_rq, as | |
1939 | * part of active balancing operations within "domain". | |
1940 | * Returns 1 if successful and 0 otherwise. | |
1941 | * | |
1942 | * Called with both runqueues locked. | |
1943 | */ | |
1944 | static int | |
1945 | move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
1946 | struct sched_domain *sd, enum cpu_idle_type idle) | |
1947 | { | |
1948 | struct task_struct *p, *n; | |
1949 | struct cfs_rq *cfs_rq; | |
1950 | int pinned = 0; | |
1951 | ||
1952 | for_each_leaf_cfs_rq(busiest, cfs_rq) { | |
1953 | list_for_each_entry_safe(p, n, &cfs_rq->tasks, se.group_node) { | |
1954 | ||
1955 | if (!can_migrate_task(p, busiest, this_cpu, | |
1956 | sd, idle, &pinned)) | |
1957 | continue; | |
1958 | ||
1959 | pull_task(busiest, p, this_rq, this_cpu); | |
1960 | /* | |
1961 | * Right now, this is only the second place pull_task() | |
1962 | * is called, so we can safely collect pull_task() | |
1963 | * stats here rather than inside pull_task(). | |
1964 | */ | |
1965 | schedstat_inc(sd, lb_gained[idle]); | |
1966 | return 1; | |
1967 | } | |
1968 | } | |
1969 | ||
1970 | return 0; | |
1971 | } | |
1972 | ||
1e3c88bd PZ |
1973 | static unsigned long |
1974 | balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
1975 | unsigned long max_load_move, struct sched_domain *sd, | |
1976 | enum cpu_idle_type idle, int *all_pinned, | |
ee00e66f | 1977 | int *this_best_prio, struct cfs_rq *busiest_cfs_rq) |
1e3c88bd PZ |
1978 | { |
1979 | int loops = 0, pulled = 0, pinned = 0; | |
1e3c88bd | 1980 | long rem_load_move = max_load_move; |
ee00e66f | 1981 | struct task_struct *p, *n; |
1e3c88bd PZ |
1982 | |
1983 | if (max_load_move == 0) | |
1984 | goto out; | |
1985 | ||
1986 | pinned = 1; | |
1987 | ||
ee00e66f PZ |
1988 | list_for_each_entry_safe(p, n, &busiest_cfs_rq->tasks, se.group_node) { |
1989 | if (loops++ > sysctl_sched_nr_migrate) | |
1990 | break; | |
1e3c88bd | 1991 | |
ee00e66f PZ |
1992 | if ((p->se.load.weight >> 1) > rem_load_move || |
1993 | !can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) | |
1994 | continue; | |
1e3c88bd | 1995 | |
ee00e66f PZ |
1996 | pull_task(busiest, p, this_rq, this_cpu); |
1997 | pulled++; | |
1998 | rem_load_move -= p->se.load.weight; | |
1e3c88bd PZ |
1999 | |
2000 | #ifdef CONFIG_PREEMPT | |
ee00e66f PZ |
2001 | /* |
2002 | * NEWIDLE balancing is a source of latency, so preemptible | |
2003 | * kernels will stop after the first task is pulled to minimize | |
2004 | * the critical section. | |
2005 | */ | |
2006 | if (idle == CPU_NEWLY_IDLE) | |
2007 | break; | |
1e3c88bd PZ |
2008 | #endif |
2009 | ||
ee00e66f PZ |
2010 | /* |
2011 | * We only want to steal up to the prescribed amount of | |
2012 | * weighted load. | |
2013 | */ | |
2014 | if (rem_load_move <= 0) | |
2015 | break; | |
2016 | ||
1e3c88bd PZ |
2017 | if (p->prio < *this_best_prio) |
2018 | *this_best_prio = p->prio; | |
1e3c88bd PZ |
2019 | } |
2020 | out: | |
2021 | /* | |
2022 | * Right now, this is one of only two places pull_task() is called, | |
2023 | * so we can safely collect pull_task() stats here rather than | |
2024 | * inside pull_task(). | |
2025 | */ | |
2026 | schedstat_add(sd, lb_gained[idle], pulled); | |
2027 | ||
2028 | if (all_pinned) | |
2029 | *all_pinned = pinned; | |
2030 | ||
2031 | return max_load_move - rem_load_move; | |
2032 | } | |
2033 | ||
230059de | 2034 | #ifdef CONFIG_FAIR_GROUP_SCHED |
9e3081ca PZ |
2035 | /* |
2036 | * update tg->load_weight by folding this cpu's load_avg | |
2037 | */ | |
67e86250 | 2038 | static int update_shares_cpu(struct task_group *tg, int cpu) |
9e3081ca PZ |
2039 | { |
2040 | struct cfs_rq *cfs_rq; | |
2041 | unsigned long flags; | |
2042 | struct rq *rq; | |
2043 | long load_avg; | |
2044 | ||
2045 | if (!tg->se[cpu]) | |
2046 | return 0; | |
2047 | ||
2048 | rq = cpu_rq(cpu); | |
2049 | cfs_rq = tg->cfs_rq[cpu]; | |
2050 | ||
2051 | raw_spin_lock_irqsave(&rq->lock, flags); | |
2052 | ||
2053 | update_rq_clock(rq); | |
e33078ba | 2054 | update_cfs_load(cfs_rq); |
9e3081ca PZ |
2055 | |
2056 | load_avg = div64_u64(cfs_rq->load_avg, cfs_rq->load_period+1); | |
2057 | load_avg -= cfs_rq->load_contribution; | |
2058 | atomic_add(load_avg, &tg->load_weight); | |
2059 | cfs_rq->load_contribution += load_avg; | |
2060 | ||
2061 | /* | |
2062 | * We need to update shares after updating tg->load_weight in | |
2063 | * order to adjust the weight of groups with long running tasks. | |
2064 | */ | |
f0d7442a | 2065 | update_cfs_shares(cfs_rq, 0); |
9e3081ca PZ |
2066 | |
2067 | raw_spin_unlock_irqrestore(&rq->lock, flags); | |
2068 | ||
2069 | return 0; | |
2070 | } | |
2071 | ||
2072 | static void update_shares(int cpu) | |
2073 | { | |
2074 | struct cfs_rq *cfs_rq; | |
2075 | struct rq *rq = cpu_rq(cpu); | |
2076 | ||
2077 | rcu_read_lock(); | |
67e86250 PT |
2078 | for_each_leaf_cfs_rq(rq, cfs_rq) |
2079 | update_shares_cpu(cfs_rq->tg, cpu); | |
9e3081ca PZ |
2080 | rcu_read_unlock(); |
2081 | } | |
2082 | ||
230059de PZ |
2083 | static unsigned long |
2084 | load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
2085 | unsigned long max_load_move, | |
2086 | struct sched_domain *sd, enum cpu_idle_type idle, | |
2087 | int *all_pinned, int *this_best_prio) | |
2088 | { | |
2089 | long rem_load_move = max_load_move; | |
2090 | int busiest_cpu = cpu_of(busiest); | |
2091 | struct task_group *tg; | |
2092 | ||
2093 | rcu_read_lock(); | |
2094 | update_h_load(busiest_cpu); | |
2095 | ||
2096 | list_for_each_entry_rcu(tg, &task_groups, list) { | |
2097 | struct cfs_rq *busiest_cfs_rq = tg->cfs_rq[busiest_cpu]; | |
2098 | unsigned long busiest_h_load = busiest_cfs_rq->h_load; | |
2099 | unsigned long busiest_weight = busiest_cfs_rq->load.weight; | |
2100 | u64 rem_load, moved_load; | |
2101 | ||
2102 | /* | |
2103 | * empty group | |
2104 | */ | |
2105 | if (!busiest_cfs_rq->task_weight) | |
2106 | continue; | |
2107 | ||
2108 | rem_load = (u64)rem_load_move * busiest_weight; | |
2109 | rem_load = div_u64(rem_load, busiest_h_load + 1); | |
2110 | ||
2111 | moved_load = balance_tasks(this_rq, this_cpu, busiest, | |
2112 | rem_load, sd, idle, all_pinned, this_best_prio, | |
2113 | busiest_cfs_rq); | |
2114 | ||
2115 | if (!moved_load) | |
2116 | continue; | |
2117 | ||
2118 | moved_load *= busiest_h_load; | |
2119 | moved_load = div_u64(moved_load, busiest_weight + 1); | |
2120 | ||
2121 | rem_load_move -= moved_load; | |
2122 | if (rem_load_move < 0) | |
2123 | break; | |
2124 | } | |
2125 | rcu_read_unlock(); | |
2126 | ||
2127 | return max_load_move - rem_load_move; | |
2128 | } | |
2129 | #else | |
9e3081ca PZ |
2130 | static inline void update_shares(int cpu) |
2131 | { | |
2132 | } | |
2133 | ||
230059de PZ |
2134 | static unsigned long |
2135 | load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
2136 | unsigned long max_load_move, | |
2137 | struct sched_domain *sd, enum cpu_idle_type idle, | |
2138 | int *all_pinned, int *this_best_prio) | |
2139 | { | |
2140 | return balance_tasks(this_rq, this_cpu, busiest, | |
2141 | max_load_move, sd, idle, all_pinned, | |
2142 | this_best_prio, &busiest->cfs); | |
2143 | } | |
2144 | #endif | |
2145 | ||
1e3c88bd PZ |
2146 | /* |
2147 | * move_tasks tries to move up to max_load_move weighted load from busiest to | |
2148 | * this_rq, as part of a balancing operation within domain "sd". | |
2149 | * Returns 1 if successful and 0 otherwise. | |
2150 | * | |
2151 | * Called with both runqueues locked. | |
2152 | */ | |
2153 | static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
2154 | unsigned long max_load_move, | |
2155 | struct sched_domain *sd, enum cpu_idle_type idle, | |
2156 | int *all_pinned) | |
2157 | { | |
3d45fd80 | 2158 | unsigned long total_load_moved = 0, load_moved; |
1e3c88bd PZ |
2159 | int this_best_prio = this_rq->curr->prio; |
2160 | ||
2161 | do { | |
3d45fd80 | 2162 | load_moved = load_balance_fair(this_rq, this_cpu, busiest, |
1e3c88bd PZ |
2163 | max_load_move - total_load_moved, |
2164 | sd, idle, all_pinned, &this_best_prio); | |
3d45fd80 PZ |
2165 | |
2166 | total_load_moved += load_moved; | |
1e3c88bd PZ |
2167 | |
2168 | #ifdef CONFIG_PREEMPT | |
2169 | /* | |
2170 | * NEWIDLE balancing is a source of latency, so preemptible | |
2171 | * kernels will stop after the first task is pulled to minimize | |
2172 | * the critical section. | |
2173 | */ | |
2174 | if (idle == CPU_NEWLY_IDLE && this_rq->nr_running) | |
2175 | break; | |
baa8c110 PZ |
2176 | |
2177 | if (raw_spin_is_contended(&this_rq->lock) || | |
2178 | raw_spin_is_contended(&busiest->lock)) | |
2179 | break; | |
1e3c88bd | 2180 | #endif |
3d45fd80 | 2181 | } while (load_moved && max_load_move > total_load_moved); |
1e3c88bd PZ |
2182 | |
2183 | return total_load_moved > 0; | |
2184 | } | |
2185 | ||
1e3c88bd PZ |
2186 | /********** Helpers for find_busiest_group ************************/ |
2187 | /* | |
2188 | * sd_lb_stats - Structure to store the statistics of a sched_domain | |
2189 | * during load balancing. | |
2190 | */ | |
2191 | struct sd_lb_stats { | |
2192 | struct sched_group *busiest; /* Busiest group in this sd */ | |
2193 | struct sched_group *this; /* Local group in this sd */ | |
2194 | unsigned long total_load; /* Total load of all groups in sd */ | |
2195 | unsigned long total_pwr; /* Total power of all groups in sd */ | |
2196 | unsigned long avg_load; /* Average load across all groups in sd */ | |
2197 | ||
2198 | /** Statistics of this group */ | |
2199 | unsigned long this_load; | |
2200 | unsigned long this_load_per_task; | |
2201 | unsigned long this_nr_running; | |
fab47622 | 2202 | unsigned long this_has_capacity; |
1e3c88bd PZ |
2203 | |
2204 | /* Statistics of the busiest group */ | |
2205 | unsigned long max_load; | |
2206 | unsigned long busiest_load_per_task; | |
2207 | unsigned long busiest_nr_running; | |
dd5feea1 | 2208 | unsigned long busiest_group_capacity; |
fab47622 | 2209 | unsigned long busiest_has_capacity; |
1e3c88bd PZ |
2210 | |
2211 | int group_imb; /* Is there imbalance in this sd */ | |
2212 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) | |
2213 | int power_savings_balance; /* Is powersave balance needed for this sd */ | |
2214 | struct sched_group *group_min; /* Least loaded group in sd */ | |
2215 | struct sched_group *group_leader; /* Group which relieves group_min */ | |
2216 | unsigned long min_load_per_task; /* load_per_task in group_min */ | |
2217 | unsigned long leader_nr_running; /* Nr running of group_leader */ | |
2218 | unsigned long min_nr_running; /* Nr running of group_min */ | |
2219 | #endif | |
2220 | }; | |
2221 | ||
2222 | /* | |
2223 | * sg_lb_stats - stats of a sched_group required for load_balancing | |
2224 | */ | |
2225 | struct sg_lb_stats { | |
2226 | unsigned long avg_load; /*Avg load across the CPUs of the group */ | |
2227 | unsigned long group_load; /* Total load over the CPUs of the group */ | |
2228 | unsigned long sum_nr_running; /* Nr tasks running in the group */ | |
2229 | unsigned long sum_weighted_load; /* Weighted load of group's tasks */ | |
2230 | unsigned long group_capacity; | |
2231 | int group_imb; /* Is there an imbalance in the group ? */ | |
fab47622 | 2232 | int group_has_capacity; /* Is there extra capacity in the group? */ |
1e3c88bd PZ |
2233 | }; |
2234 | ||
2235 | /** | |
2236 | * group_first_cpu - Returns the first cpu in the cpumask of a sched_group. | |
2237 | * @group: The group whose first cpu is to be returned. | |
2238 | */ | |
2239 | static inline unsigned int group_first_cpu(struct sched_group *group) | |
2240 | { | |
2241 | return cpumask_first(sched_group_cpus(group)); | |
2242 | } | |
2243 | ||
2244 | /** | |
2245 | * get_sd_load_idx - Obtain the load index for a given sched domain. | |
2246 | * @sd: The sched_domain whose load_idx is to be obtained. | |
2247 | * @idle: The Idle status of the CPU for whose sd load_icx is obtained. | |
2248 | */ | |
2249 | static inline int get_sd_load_idx(struct sched_domain *sd, | |
2250 | enum cpu_idle_type idle) | |
2251 | { | |
2252 | int load_idx; | |
2253 | ||
2254 | switch (idle) { | |
2255 | case CPU_NOT_IDLE: | |
2256 | load_idx = sd->busy_idx; | |
2257 | break; | |
2258 | ||
2259 | case CPU_NEWLY_IDLE: | |
2260 | load_idx = sd->newidle_idx; | |
2261 | break; | |
2262 | default: | |
2263 | load_idx = sd->idle_idx; | |
2264 | break; | |
2265 | } | |
2266 | ||
2267 | return load_idx; | |
2268 | } | |
2269 | ||
2270 | ||
2271 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) | |
2272 | /** | |
2273 | * init_sd_power_savings_stats - Initialize power savings statistics for | |
2274 | * the given sched_domain, during load balancing. | |
2275 | * | |
2276 | * @sd: Sched domain whose power-savings statistics are to be initialized. | |
2277 | * @sds: Variable containing the statistics for sd. | |
2278 | * @idle: Idle status of the CPU at which we're performing load-balancing. | |
2279 | */ | |
2280 | static inline void init_sd_power_savings_stats(struct sched_domain *sd, | |
2281 | struct sd_lb_stats *sds, enum cpu_idle_type idle) | |
2282 | { | |
2283 | /* | |
2284 | * Busy processors will not participate in power savings | |
2285 | * balance. | |
2286 | */ | |
2287 | if (idle == CPU_NOT_IDLE || !(sd->flags & SD_POWERSAVINGS_BALANCE)) | |
2288 | sds->power_savings_balance = 0; | |
2289 | else { | |
2290 | sds->power_savings_balance = 1; | |
2291 | sds->min_nr_running = ULONG_MAX; | |
2292 | sds->leader_nr_running = 0; | |
2293 | } | |
2294 | } | |
2295 | ||
2296 | /** | |
2297 | * update_sd_power_savings_stats - Update the power saving stats for a | |
2298 | * sched_domain while performing load balancing. | |
2299 | * | |
2300 | * @group: sched_group belonging to the sched_domain under consideration. | |
2301 | * @sds: Variable containing the statistics of the sched_domain | |
2302 | * @local_group: Does group contain the CPU for which we're performing | |
2303 | * load balancing ? | |
2304 | * @sgs: Variable containing the statistics of the group. | |
2305 | */ | |
2306 | static inline void update_sd_power_savings_stats(struct sched_group *group, | |
2307 | struct sd_lb_stats *sds, int local_group, struct sg_lb_stats *sgs) | |
2308 | { | |
2309 | ||
2310 | if (!sds->power_savings_balance) | |
2311 | return; | |
2312 | ||
2313 | /* | |
2314 | * If the local group is idle or completely loaded | |
2315 | * no need to do power savings balance at this domain | |
2316 | */ | |
2317 | if (local_group && (sds->this_nr_running >= sgs->group_capacity || | |
2318 | !sds->this_nr_running)) | |
2319 | sds->power_savings_balance = 0; | |
2320 | ||
2321 | /* | |
2322 | * If a group is already running at full capacity or idle, | |
2323 | * don't include that group in power savings calculations | |
2324 | */ | |
2325 | if (!sds->power_savings_balance || | |
2326 | sgs->sum_nr_running >= sgs->group_capacity || | |
2327 | !sgs->sum_nr_running) | |
2328 | return; | |
2329 | ||
2330 | /* | |
2331 | * Calculate the group which has the least non-idle load. | |
2332 | * This is the group from where we need to pick up the load | |
2333 | * for saving power | |
2334 | */ | |
2335 | if ((sgs->sum_nr_running < sds->min_nr_running) || | |
2336 | (sgs->sum_nr_running == sds->min_nr_running && | |
2337 | group_first_cpu(group) > group_first_cpu(sds->group_min))) { | |
2338 | sds->group_min = group; | |
2339 | sds->min_nr_running = sgs->sum_nr_running; | |
2340 | sds->min_load_per_task = sgs->sum_weighted_load / | |
2341 | sgs->sum_nr_running; | |
2342 | } | |
2343 | ||
2344 | /* | |
2345 | * Calculate the group which is almost near its | |
2346 | * capacity but still has some space to pick up some load | |
2347 | * from other group and save more power | |
2348 | */ | |
2349 | if (sgs->sum_nr_running + 1 > sgs->group_capacity) | |
2350 | return; | |
2351 | ||
2352 | if (sgs->sum_nr_running > sds->leader_nr_running || | |
2353 | (sgs->sum_nr_running == sds->leader_nr_running && | |
2354 | group_first_cpu(group) < group_first_cpu(sds->group_leader))) { | |
2355 | sds->group_leader = group; | |
2356 | sds->leader_nr_running = sgs->sum_nr_running; | |
2357 | } | |
2358 | } | |
2359 | ||
2360 | /** | |
2361 | * check_power_save_busiest_group - see if there is potential for some power-savings balance | |
2362 | * @sds: Variable containing the statistics of the sched_domain | |
2363 | * under consideration. | |
2364 | * @this_cpu: Cpu at which we're currently performing load-balancing. | |
2365 | * @imbalance: Variable to store the imbalance. | |
2366 | * | |
2367 | * Description: | |
2368 | * Check if we have potential to perform some power-savings balance. | |
2369 | * If yes, set the busiest group to be the least loaded group in the | |
2370 | * sched_domain, so that it's CPUs can be put to idle. | |
2371 | * | |
2372 | * Returns 1 if there is potential to perform power-savings balance. | |
2373 | * Else returns 0. | |
2374 | */ | |
2375 | static inline int check_power_save_busiest_group(struct sd_lb_stats *sds, | |
2376 | int this_cpu, unsigned long *imbalance) | |
2377 | { | |
2378 | if (!sds->power_savings_balance) | |
2379 | return 0; | |
2380 | ||
2381 | if (sds->this != sds->group_leader || | |
2382 | sds->group_leader == sds->group_min) | |
2383 | return 0; | |
2384 | ||
2385 | *imbalance = sds->min_load_per_task; | |
2386 | sds->busiest = sds->group_min; | |
2387 | ||
2388 | return 1; | |
2389 | ||
2390 | } | |
2391 | #else /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */ | |
2392 | static inline void init_sd_power_savings_stats(struct sched_domain *sd, | |
2393 | struct sd_lb_stats *sds, enum cpu_idle_type idle) | |
2394 | { | |
2395 | return; | |
2396 | } | |
2397 | ||
2398 | static inline void update_sd_power_savings_stats(struct sched_group *group, | |
2399 | struct sd_lb_stats *sds, int local_group, struct sg_lb_stats *sgs) | |
2400 | { | |
2401 | return; | |
2402 | } | |
2403 | ||
2404 | static inline int check_power_save_busiest_group(struct sd_lb_stats *sds, | |
2405 | int this_cpu, unsigned long *imbalance) | |
2406 | { | |
2407 | return 0; | |
2408 | } | |
2409 | #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */ | |
2410 | ||
2411 | ||
2412 | unsigned long default_scale_freq_power(struct sched_domain *sd, int cpu) | |
2413 | { | |
2414 | return SCHED_LOAD_SCALE; | |
2415 | } | |
2416 | ||
2417 | unsigned long __weak arch_scale_freq_power(struct sched_domain *sd, int cpu) | |
2418 | { | |
2419 | return default_scale_freq_power(sd, cpu); | |
2420 | } | |
2421 | ||
2422 | unsigned long default_scale_smt_power(struct sched_domain *sd, int cpu) | |
2423 | { | |
669c55e9 | 2424 | unsigned long weight = sd->span_weight; |
1e3c88bd PZ |
2425 | unsigned long smt_gain = sd->smt_gain; |
2426 | ||
2427 | smt_gain /= weight; | |
2428 | ||
2429 | return smt_gain; | |
2430 | } | |
2431 | ||
2432 | unsigned long __weak arch_scale_smt_power(struct sched_domain *sd, int cpu) | |
2433 | { | |
2434 | return default_scale_smt_power(sd, cpu); | |
2435 | } | |
2436 | ||
2437 | unsigned long scale_rt_power(int cpu) | |
2438 | { | |
2439 | struct rq *rq = cpu_rq(cpu); | |
2440 | u64 total, available; | |
2441 | ||
1e3c88bd | 2442 | total = sched_avg_period() + (rq->clock - rq->age_stamp); |
aa483808 VP |
2443 | |
2444 | if (unlikely(total < rq->rt_avg)) { | |
2445 | /* Ensures that power won't end up being negative */ | |
2446 | available = 0; | |
2447 | } else { | |
2448 | available = total - rq->rt_avg; | |
2449 | } | |
1e3c88bd PZ |
2450 | |
2451 | if (unlikely((s64)total < SCHED_LOAD_SCALE)) | |
2452 | total = SCHED_LOAD_SCALE; | |
2453 | ||
2454 | total >>= SCHED_LOAD_SHIFT; | |
2455 | ||
2456 | return div_u64(available, total); | |
2457 | } | |
2458 | ||
2459 | static void update_cpu_power(struct sched_domain *sd, int cpu) | |
2460 | { | |
669c55e9 | 2461 | unsigned long weight = sd->span_weight; |
1e3c88bd PZ |
2462 | unsigned long power = SCHED_LOAD_SCALE; |
2463 | struct sched_group *sdg = sd->groups; | |
2464 | ||
1e3c88bd PZ |
2465 | if ((sd->flags & SD_SHARE_CPUPOWER) && weight > 1) { |
2466 | if (sched_feat(ARCH_POWER)) | |
2467 | power *= arch_scale_smt_power(sd, cpu); | |
2468 | else | |
2469 | power *= default_scale_smt_power(sd, cpu); | |
2470 | ||
2471 | power >>= SCHED_LOAD_SHIFT; | |
2472 | } | |
2473 | ||
9d5efe05 SV |
2474 | sdg->cpu_power_orig = power; |
2475 | ||
2476 | if (sched_feat(ARCH_POWER)) | |
2477 | power *= arch_scale_freq_power(sd, cpu); | |
2478 | else | |
2479 | power *= default_scale_freq_power(sd, cpu); | |
2480 | ||
2481 | power >>= SCHED_LOAD_SHIFT; | |
2482 | ||
1e3c88bd PZ |
2483 | power *= scale_rt_power(cpu); |
2484 | power >>= SCHED_LOAD_SHIFT; | |
2485 | ||
2486 | if (!power) | |
2487 | power = 1; | |
2488 | ||
e51fd5e2 | 2489 | cpu_rq(cpu)->cpu_power = power; |
1e3c88bd PZ |
2490 | sdg->cpu_power = power; |
2491 | } | |
2492 | ||
2493 | static void update_group_power(struct sched_domain *sd, int cpu) | |
2494 | { | |
2495 | struct sched_domain *child = sd->child; | |
2496 | struct sched_group *group, *sdg = sd->groups; | |
2497 | unsigned long power; | |
2498 | ||
2499 | if (!child) { | |
2500 | update_cpu_power(sd, cpu); | |
2501 | return; | |
2502 | } | |
2503 | ||
2504 | power = 0; | |
2505 | ||
2506 | group = child->groups; | |
2507 | do { | |
2508 | power += group->cpu_power; | |
2509 | group = group->next; | |
2510 | } while (group != child->groups); | |
2511 | ||
2512 | sdg->cpu_power = power; | |
2513 | } | |
2514 | ||
9d5efe05 SV |
2515 | /* |
2516 | * Try and fix up capacity for tiny siblings, this is needed when | |
2517 | * things like SD_ASYM_PACKING need f_b_g to select another sibling | |
2518 | * which on its own isn't powerful enough. | |
2519 | * | |
2520 | * See update_sd_pick_busiest() and check_asym_packing(). | |
2521 | */ | |
2522 | static inline int | |
2523 | fix_small_capacity(struct sched_domain *sd, struct sched_group *group) | |
2524 | { | |
2525 | /* | |
2526 | * Only siblings can have significantly less than SCHED_LOAD_SCALE | |
2527 | */ | |
2528 | if (sd->level != SD_LV_SIBLING) | |
2529 | return 0; | |
2530 | ||
2531 | /* | |
2532 | * If ~90% of the cpu_power is still there, we're good. | |
2533 | */ | |
694f5a11 | 2534 | if (group->cpu_power * 32 > group->cpu_power_orig * 29) |
9d5efe05 SV |
2535 | return 1; |
2536 | ||
2537 | return 0; | |
2538 | } | |
2539 | ||
1e3c88bd PZ |
2540 | /** |
2541 | * update_sg_lb_stats - Update sched_group's statistics for load balancing. | |
2542 | * @sd: The sched_domain whose statistics are to be updated. | |
2543 | * @group: sched_group whose statistics are to be updated. | |
2544 | * @this_cpu: Cpu for which load balance is currently performed. | |
2545 | * @idle: Idle status of this_cpu | |
2546 | * @load_idx: Load index of sched_domain of this_cpu for load calc. | |
2547 | * @sd_idle: Idle status of the sched_domain containing group. | |
2548 | * @local_group: Does group contain this_cpu. | |
2549 | * @cpus: Set of cpus considered for load balancing. | |
2550 | * @balance: Should we balance. | |
2551 | * @sgs: variable to hold the statistics for this group. | |
2552 | */ | |
2553 | static inline void update_sg_lb_stats(struct sched_domain *sd, | |
2554 | struct sched_group *group, int this_cpu, | |
2555 | enum cpu_idle_type idle, int load_idx, int *sd_idle, | |
2556 | int local_group, const struct cpumask *cpus, | |
2557 | int *balance, struct sg_lb_stats *sgs) | |
2558 | { | |
2582f0eb | 2559 | unsigned long load, max_cpu_load, min_cpu_load, max_nr_running; |
1e3c88bd PZ |
2560 | int i; |
2561 | unsigned int balance_cpu = -1, first_idle_cpu = 0; | |
dd5feea1 | 2562 | unsigned long avg_load_per_task = 0; |
1e3c88bd | 2563 | |
871e35bc | 2564 | if (local_group) |
1e3c88bd | 2565 | balance_cpu = group_first_cpu(group); |
1e3c88bd PZ |
2566 | |
2567 | /* Tally up the load of all CPUs in the group */ | |
1e3c88bd PZ |
2568 | max_cpu_load = 0; |
2569 | min_cpu_load = ~0UL; | |
2582f0eb | 2570 | max_nr_running = 0; |
1e3c88bd PZ |
2571 | |
2572 | for_each_cpu_and(i, sched_group_cpus(group), cpus) { | |
2573 | struct rq *rq = cpu_rq(i); | |
2574 | ||
2575 | if (*sd_idle && rq->nr_running) | |
2576 | *sd_idle = 0; | |
2577 | ||
2578 | /* Bias balancing toward cpus of our domain */ | |
2579 | if (local_group) { | |
2580 | if (idle_cpu(i) && !first_idle_cpu) { | |
2581 | first_idle_cpu = 1; | |
2582 | balance_cpu = i; | |
2583 | } | |
2584 | ||
2585 | load = target_load(i, load_idx); | |
2586 | } else { | |
2587 | load = source_load(i, load_idx); | |
2582f0eb | 2588 | if (load > max_cpu_load) { |
1e3c88bd | 2589 | max_cpu_load = load; |
2582f0eb NR |
2590 | max_nr_running = rq->nr_running; |
2591 | } | |
1e3c88bd PZ |
2592 | if (min_cpu_load > load) |
2593 | min_cpu_load = load; | |
2594 | } | |
2595 | ||
2596 | sgs->group_load += load; | |
2597 | sgs->sum_nr_running += rq->nr_running; | |
2598 | sgs->sum_weighted_load += weighted_cpuload(i); | |
2599 | ||
1e3c88bd PZ |
2600 | } |
2601 | ||
2602 | /* | |
2603 | * First idle cpu or the first cpu(busiest) in this sched group | |
2604 | * is eligible for doing load balancing at this and above | |
2605 | * domains. In the newly idle case, we will allow all the cpu's | |
2606 | * to do the newly idle load balance. | |
2607 | */ | |
bbc8cb5b PZ |
2608 | if (idle != CPU_NEWLY_IDLE && local_group) { |
2609 | if (balance_cpu != this_cpu) { | |
2610 | *balance = 0; | |
2611 | return; | |
2612 | } | |
2613 | update_group_power(sd, this_cpu); | |
1e3c88bd PZ |
2614 | } |
2615 | ||
2616 | /* Adjust by relative CPU power of the group */ | |
2617 | sgs->avg_load = (sgs->group_load * SCHED_LOAD_SCALE) / group->cpu_power; | |
2618 | ||
1e3c88bd PZ |
2619 | /* |
2620 | * Consider the group unbalanced when the imbalance is larger | |
2621 | * than the average weight of two tasks. | |
2622 | * | |
2623 | * APZ: with cgroup the avg task weight can vary wildly and | |
2624 | * might not be a suitable number - should we keep a | |
2625 | * normalized nr_running number somewhere that negates | |
2626 | * the hierarchy? | |
2627 | */ | |
dd5feea1 SS |
2628 | if (sgs->sum_nr_running) |
2629 | avg_load_per_task = sgs->sum_weighted_load / sgs->sum_nr_running; | |
1e3c88bd | 2630 | |
2582f0eb | 2631 | if ((max_cpu_load - min_cpu_load) > 2*avg_load_per_task && max_nr_running > 1) |
1e3c88bd PZ |
2632 | sgs->group_imb = 1; |
2633 | ||
2582f0eb | 2634 | sgs->group_capacity = DIV_ROUND_CLOSEST(group->cpu_power, SCHED_LOAD_SCALE); |
9d5efe05 SV |
2635 | if (!sgs->group_capacity) |
2636 | sgs->group_capacity = fix_small_capacity(sd, group); | |
fab47622 NR |
2637 | |
2638 | if (sgs->group_capacity > sgs->sum_nr_running) | |
2639 | sgs->group_has_capacity = 1; | |
1e3c88bd PZ |
2640 | } |
2641 | ||
532cb4c4 MN |
2642 | /** |
2643 | * update_sd_pick_busiest - return 1 on busiest group | |
2644 | * @sd: sched_domain whose statistics are to be checked | |
2645 | * @sds: sched_domain statistics | |
2646 | * @sg: sched_group candidate to be checked for being the busiest | |
b6b12294 MN |
2647 | * @sgs: sched_group statistics |
2648 | * @this_cpu: the current cpu | |
532cb4c4 MN |
2649 | * |
2650 | * Determine if @sg is a busier group than the previously selected | |
2651 | * busiest group. | |
2652 | */ | |
2653 | static bool update_sd_pick_busiest(struct sched_domain *sd, | |
2654 | struct sd_lb_stats *sds, | |
2655 | struct sched_group *sg, | |
2656 | struct sg_lb_stats *sgs, | |
2657 | int this_cpu) | |
2658 | { | |
2659 | if (sgs->avg_load <= sds->max_load) | |
2660 | return false; | |
2661 | ||
2662 | if (sgs->sum_nr_running > sgs->group_capacity) | |
2663 | return true; | |
2664 | ||
2665 | if (sgs->group_imb) | |
2666 | return true; | |
2667 | ||
2668 | /* | |
2669 | * ASYM_PACKING needs to move all the work to the lowest | |
2670 | * numbered CPUs in the group, therefore mark all groups | |
2671 | * higher than ourself as busy. | |
2672 | */ | |
2673 | if ((sd->flags & SD_ASYM_PACKING) && sgs->sum_nr_running && | |
2674 | this_cpu < group_first_cpu(sg)) { | |
2675 | if (!sds->busiest) | |
2676 | return true; | |
2677 | ||
2678 | if (group_first_cpu(sds->busiest) > group_first_cpu(sg)) | |
2679 | return true; | |
2680 | } | |
2681 | ||
2682 | return false; | |
2683 | } | |
2684 | ||
1e3c88bd PZ |
2685 | /** |
2686 | * update_sd_lb_stats - Update sched_group's statistics for load balancing. | |
2687 | * @sd: sched_domain whose statistics are to be updated. | |
2688 | * @this_cpu: Cpu for which load balance is currently performed. | |
2689 | * @idle: Idle status of this_cpu | |
532cb4c4 | 2690 | * @sd_idle: Idle status of the sched_domain containing sg. |
1e3c88bd PZ |
2691 | * @cpus: Set of cpus considered for load balancing. |
2692 | * @balance: Should we balance. | |
2693 | * @sds: variable to hold the statistics for this sched_domain. | |
2694 | */ | |
2695 | static inline void update_sd_lb_stats(struct sched_domain *sd, int this_cpu, | |
2696 | enum cpu_idle_type idle, int *sd_idle, | |
2697 | const struct cpumask *cpus, int *balance, | |
2698 | struct sd_lb_stats *sds) | |
2699 | { | |
2700 | struct sched_domain *child = sd->child; | |
532cb4c4 | 2701 | struct sched_group *sg = sd->groups; |
1e3c88bd PZ |
2702 | struct sg_lb_stats sgs; |
2703 | int load_idx, prefer_sibling = 0; | |
2704 | ||
2705 | if (child && child->flags & SD_PREFER_SIBLING) | |
2706 | prefer_sibling = 1; | |
2707 | ||
2708 | init_sd_power_savings_stats(sd, sds, idle); | |
2709 | load_idx = get_sd_load_idx(sd, idle); | |
2710 | ||
2711 | do { | |
2712 | int local_group; | |
2713 | ||
532cb4c4 | 2714 | local_group = cpumask_test_cpu(this_cpu, sched_group_cpus(sg)); |
1e3c88bd | 2715 | memset(&sgs, 0, sizeof(sgs)); |
532cb4c4 | 2716 | update_sg_lb_stats(sd, sg, this_cpu, idle, load_idx, sd_idle, |
1e3c88bd PZ |
2717 | local_group, cpus, balance, &sgs); |
2718 | ||
8f190fb3 | 2719 | if (local_group && !(*balance)) |
1e3c88bd PZ |
2720 | return; |
2721 | ||
2722 | sds->total_load += sgs.group_load; | |
532cb4c4 | 2723 | sds->total_pwr += sg->cpu_power; |
1e3c88bd PZ |
2724 | |
2725 | /* | |
2726 | * In case the child domain prefers tasks go to siblings | |
532cb4c4 | 2727 | * first, lower the sg capacity to one so that we'll try |
75dd321d NR |
2728 | * and move all the excess tasks away. We lower the capacity |
2729 | * of a group only if the local group has the capacity to fit | |
2730 | * these excess tasks, i.e. nr_running < group_capacity. The | |
2731 | * extra check prevents the case where you always pull from the | |
2732 | * heaviest group when it is already under-utilized (possible | |
2733 | * with a large weight task outweighs the tasks on the system). | |
1e3c88bd | 2734 | */ |
75dd321d | 2735 | if (prefer_sibling && !local_group && sds->this_has_capacity) |
1e3c88bd PZ |
2736 | sgs.group_capacity = min(sgs.group_capacity, 1UL); |
2737 | ||
2738 | if (local_group) { | |
2739 | sds->this_load = sgs.avg_load; | |
532cb4c4 | 2740 | sds->this = sg; |
1e3c88bd PZ |
2741 | sds->this_nr_running = sgs.sum_nr_running; |
2742 | sds->this_load_per_task = sgs.sum_weighted_load; | |
fab47622 | 2743 | sds->this_has_capacity = sgs.group_has_capacity; |
532cb4c4 | 2744 | } else if (update_sd_pick_busiest(sd, sds, sg, &sgs, this_cpu)) { |
1e3c88bd | 2745 | sds->max_load = sgs.avg_load; |
532cb4c4 | 2746 | sds->busiest = sg; |
1e3c88bd | 2747 | sds->busiest_nr_running = sgs.sum_nr_running; |
dd5feea1 | 2748 | sds->busiest_group_capacity = sgs.group_capacity; |
1e3c88bd | 2749 | sds->busiest_load_per_task = sgs.sum_weighted_load; |
fab47622 | 2750 | sds->busiest_has_capacity = sgs.group_has_capacity; |
1e3c88bd PZ |
2751 | sds->group_imb = sgs.group_imb; |
2752 | } | |
2753 | ||
532cb4c4 MN |
2754 | update_sd_power_savings_stats(sg, sds, local_group, &sgs); |
2755 | sg = sg->next; | |
2756 | } while (sg != sd->groups); | |
2757 | } | |
2758 | ||
2ec57d44 | 2759 | int __weak arch_sd_sibling_asym_packing(void) |
532cb4c4 MN |
2760 | { |
2761 | return 0*SD_ASYM_PACKING; | |
2762 | } | |
2763 | ||
2764 | /** | |
2765 | * check_asym_packing - Check to see if the group is packed into the | |
2766 | * sched doman. | |
2767 | * | |
2768 | * This is primarily intended to used at the sibling level. Some | |
2769 | * cores like POWER7 prefer to use lower numbered SMT threads. In the | |
2770 | * case of POWER7, it can move to lower SMT modes only when higher | |
2771 | * threads are idle. When in lower SMT modes, the threads will | |
2772 | * perform better since they share less core resources. Hence when we | |
2773 | * have idle threads, we want them to be the higher ones. | |
2774 | * | |
2775 | * This packing function is run on idle threads. It checks to see if | |
2776 | * the busiest CPU in this domain (core in the P7 case) has a higher | |
2777 | * CPU number than the packing function is being run on. Here we are | |
2778 | * assuming lower CPU number will be equivalent to lower a SMT thread | |
2779 | * number. | |
2780 | * | |
b6b12294 MN |
2781 | * Returns 1 when packing is required and a task should be moved to |
2782 | * this CPU. The amount of the imbalance is returned in *imbalance. | |
2783 | * | |
532cb4c4 MN |
2784 | * @sd: The sched_domain whose packing is to be checked. |
2785 | * @sds: Statistics of the sched_domain which is to be packed | |
2786 | * @this_cpu: The cpu at whose sched_domain we're performing load-balance. | |
2787 | * @imbalance: returns amount of imbalanced due to packing. | |
532cb4c4 MN |
2788 | */ |
2789 | static int check_asym_packing(struct sched_domain *sd, | |
2790 | struct sd_lb_stats *sds, | |
2791 | int this_cpu, unsigned long *imbalance) | |
2792 | { | |
2793 | int busiest_cpu; | |
2794 | ||
2795 | if (!(sd->flags & SD_ASYM_PACKING)) | |
2796 | return 0; | |
2797 | ||
2798 | if (!sds->busiest) | |
2799 | return 0; | |
2800 | ||
2801 | busiest_cpu = group_first_cpu(sds->busiest); | |
2802 | if (this_cpu > busiest_cpu) | |
2803 | return 0; | |
2804 | ||
2805 | *imbalance = DIV_ROUND_CLOSEST(sds->max_load * sds->busiest->cpu_power, | |
2806 | SCHED_LOAD_SCALE); | |
2807 | return 1; | |
1e3c88bd PZ |
2808 | } |
2809 | ||
2810 | /** | |
2811 | * fix_small_imbalance - Calculate the minor imbalance that exists | |
2812 | * amongst the groups of a sched_domain, during | |
2813 | * load balancing. | |
2814 | * @sds: Statistics of the sched_domain whose imbalance is to be calculated. | |
2815 | * @this_cpu: The cpu at whose sched_domain we're performing load-balance. | |
2816 | * @imbalance: Variable to store the imbalance. | |
2817 | */ | |
2818 | static inline void fix_small_imbalance(struct sd_lb_stats *sds, | |
2819 | int this_cpu, unsigned long *imbalance) | |
2820 | { | |
2821 | unsigned long tmp, pwr_now = 0, pwr_move = 0; | |
2822 | unsigned int imbn = 2; | |
dd5feea1 | 2823 | unsigned long scaled_busy_load_per_task; |
1e3c88bd PZ |
2824 | |
2825 | if (sds->this_nr_running) { | |
2826 | sds->this_load_per_task /= sds->this_nr_running; | |
2827 | if (sds->busiest_load_per_task > | |
2828 | sds->this_load_per_task) | |
2829 | imbn = 1; | |
2830 | } else | |
2831 | sds->this_load_per_task = | |
2832 | cpu_avg_load_per_task(this_cpu); | |
2833 | ||
dd5feea1 SS |
2834 | scaled_busy_load_per_task = sds->busiest_load_per_task |
2835 | * SCHED_LOAD_SCALE; | |
2836 | scaled_busy_load_per_task /= sds->busiest->cpu_power; | |
2837 | ||
2838 | if (sds->max_load - sds->this_load + scaled_busy_load_per_task >= | |
2839 | (scaled_busy_load_per_task * imbn)) { | |
1e3c88bd PZ |
2840 | *imbalance = sds->busiest_load_per_task; |
2841 | return; | |
2842 | } | |
2843 | ||
2844 | /* | |
2845 | * OK, we don't have enough imbalance to justify moving tasks, | |
2846 | * however we may be able to increase total CPU power used by | |
2847 | * moving them. | |
2848 | */ | |
2849 | ||
2850 | pwr_now += sds->busiest->cpu_power * | |
2851 | min(sds->busiest_load_per_task, sds->max_load); | |
2852 | pwr_now += sds->this->cpu_power * | |
2853 | min(sds->this_load_per_task, sds->this_load); | |
2854 | pwr_now /= SCHED_LOAD_SCALE; | |
2855 | ||
2856 | /* Amount of load we'd subtract */ | |
2857 | tmp = (sds->busiest_load_per_task * SCHED_LOAD_SCALE) / | |
2858 | sds->busiest->cpu_power; | |
2859 | if (sds->max_load > tmp) | |
2860 | pwr_move += sds->busiest->cpu_power * | |
2861 | min(sds->busiest_load_per_task, sds->max_load - tmp); | |
2862 | ||
2863 | /* Amount of load we'd add */ | |
2864 | if (sds->max_load * sds->busiest->cpu_power < | |
2865 | sds->busiest_load_per_task * SCHED_LOAD_SCALE) | |
2866 | tmp = (sds->max_load * sds->busiest->cpu_power) / | |
2867 | sds->this->cpu_power; | |
2868 | else | |
2869 | tmp = (sds->busiest_load_per_task * SCHED_LOAD_SCALE) / | |
2870 | sds->this->cpu_power; | |
2871 | pwr_move += sds->this->cpu_power * | |
2872 | min(sds->this_load_per_task, sds->this_load + tmp); | |
2873 | pwr_move /= SCHED_LOAD_SCALE; | |
2874 | ||
2875 | /* Move if we gain throughput */ | |
2876 | if (pwr_move > pwr_now) | |
2877 | *imbalance = sds->busiest_load_per_task; | |
2878 | } | |
2879 | ||
2880 | /** | |
2881 | * calculate_imbalance - Calculate the amount of imbalance present within the | |
2882 | * groups of a given sched_domain during load balance. | |
2883 | * @sds: statistics of the sched_domain whose imbalance is to be calculated. | |
2884 | * @this_cpu: Cpu for which currently load balance is being performed. | |
2885 | * @imbalance: The variable to store the imbalance. | |
2886 | */ | |
2887 | static inline void calculate_imbalance(struct sd_lb_stats *sds, int this_cpu, | |
2888 | unsigned long *imbalance) | |
2889 | { | |
dd5feea1 SS |
2890 | unsigned long max_pull, load_above_capacity = ~0UL; |
2891 | ||
2892 | sds->busiest_load_per_task /= sds->busiest_nr_running; | |
2893 | if (sds->group_imb) { | |
2894 | sds->busiest_load_per_task = | |
2895 | min(sds->busiest_load_per_task, sds->avg_load); | |
2896 | } | |
2897 | ||
1e3c88bd PZ |
2898 | /* |
2899 | * In the presence of smp nice balancing, certain scenarios can have | |
2900 | * max load less than avg load(as we skip the groups at or below | |
2901 | * its cpu_power, while calculating max_load..) | |
2902 | */ | |
2903 | if (sds->max_load < sds->avg_load) { | |
2904 | *imbalance = 0; | |
2905 | return fix_small_imbalance(sds, this_cpu, imbalance); | |
2906 | } | |
2907 | ||
dd5feea1 SS |
2908 | if (!sds->group_imb) { |
2909 | /* | |
2910 | * Don't want to pull so many tasks that a group would go idle. | |
2911 | */ | |
2912 | load_above_capacity = (sds->busiest_nr_running - | |
2913 | sds->busiest_group_capacity); | |
2914 | ||
2915 | load_above_capacity *= (SCHED_LOAD_SCALE * SCHED_LOAD_SCALE); | |
2916 | ||
2917 | load_above_capacity /= sds->busiest->cpu_power; | |
2918 | } | |
2919 | ||
2920 | /* | |
2921 | * We're trying to get all the cpus to the average_load, so we don't | |
2922 | * want to push ourselves above the average load, nor do we wish to | |
2923 | * reduce the max loaded cpu below the average load. At the same time, | |
2924 | * we also don't want to reduce the group load below the group capacity | |
2925 | * (so that we can implement power-savings policies etc). Thus we look | |
2926 | * for the minimum possible imbalance. | |
2927 | * Be careful of negative numbers as they'll appear as very large values | |
2928 | * with unsigned longs. | |
2929 | */ | |
2930 | max_pull = min(sds->max_load - sds->avg_load, load_above_capacity); | |
1e3c88bd PZ |
2931 | |
2932 | /* How much load to actually move to equalise the imbalance */ | |
2933 | *imbalance = min(max_pull * sds->busiest->cpu_power, | |
2934 | (sds->avg_load - sds->this_load) * sds->this->cpu_power) | |
2935 | / SCHED_LOAD_SCALE; | |
2936 | ||
2937 | /* | |
2938 | * if *imbalance is less than the average load per runnable task | |
2939 | * there is no gaurantee that any tasks will be moved so we'll have | |
2940 | * a think about bumping its value to force at least one task to be | |
2941 | * moved | |
2942 | */ | |
2943 | if (*imbalance < sds->busiest_load_per_task) | |
2944 | return fix_small_imbalance(sds, this_cpu, imbalance); | |
2945 | ||
2946 | } | |
fab47622 | 2947 | |
1e3c88bd PZ |
2948 | /******* find_busiest_group() helpers end here *********************/ |
2949 | ||
2950 | /** | |
2951 | * find_busiest_group - Returns the busiest group within the sched_domain | |
2952 | * if there is an imbalance. If there isn't an imbalance, and | |
2953 | * the user has opted for power-savings, it returns a group whose | |
2954 | * CPUs can be put to idle by rebalancing those tasks elsewhere, if | |
2955 | * such a group exists. | |
2956 | * | |
2957 | * Also calculates the amount of weighted load which should be moved | |
2958 | * to restore balance. | |
2959 | * | |
2960 | * @sd: The sched_domain whose busiest group is to be returned. | |
2961 | * @this_cpu: The cpu for which load balancing is currently being performed. | |
2962 | * @imbalance: Variable which stores amount of weighted load which should | |
2963 | * be moved to restore balance/put a group to idle. | |
2964 | * @idle: The idle status of this_cpu. | |
2965 | * @sd_idle: The idleness of sd | |
2966 | * @cpus: The set of CPUs under consideration for load-balancing. | |
2967 | * @balance: Pointer to a variable indicating if this_cpu | |
2968 | * is the appropriate cpu to perform load balancing at this_level. | |
2969 | * | |
2970 | * Returns: - the busiest group if imbalance exists. | |
2971 | * - If no imbalance and user has opted for power-savings balance, | |
2972 | * return the least loaded group whose CPUs can be | |
2973 | * put to idle by rebalancing its tasks onto our group. | |
2974 | */ | |
2975 | static struct sched_group * | |
2976 | find_busiest_group(struct sched_domain *sd, int this_cpu, | |
2977 | unsigned long *imbalance, enum cpu_idle_type idle, | |
2978 | int *sd_idle, const struct cpumask *cpus, int *balance) | |
2979 | { | |
2980 | struct sd_lb_stats sds; | |
2981 | ||
2982 | memset(&sds, 0, sizeof(sds)); | |
2983 | ||
2984 | /* | |
2985 | * Compute the various statistics relavent for load balancing at | |
2986 | * this level. | |
2987 | */ | |
2988 | update_sd_lb_stats(sd, this_cpu, idle, sd_idle, cpus, | |
2989 | balance, &sds); | |
2990 | ||
2991 | /* Cases where imbalance does not exist from POV of this_cpu */ | |
2992 | /* 1) this_cpu is not the appropriate cpu to perform load balancing | |
2993 | * at this level. | |
2994 | * 2) There is no busy sibling group to pull from. | |
2995 | * 3) This group is the busiest group. | |
2996 | * 4) This group is more busy than the avg busieness at this | |
2997 | * sched_domain. | |
2998 | * 5) The imbalance is within the specified limit. | |
fab47622 NR |
2999 | * |
3000 | * Note: when doing newidle balance, if the local group has excess | |
3001 | * capacity (i.e. nr_running < group_capacity) and the busiest group | |
3002 | * does not have any capacity, we force a load balance to pull tasks | |
3003 | * to the local group. In this case, we skip past checks 3, 4 and 5. | |
1e3c88bd | 3004 | */ |
8f190fb3 | 3005 | if (!(*balance)) |
1e3c88bd PZ |
3006 | goto ret; |
3007 | ||
532cb4c4 MN |
3008 | if ((idle == CPU_IDLE || idle == CPU_NEWLY_IDLE) && |
3009 | check_asym_packing(sd, &sds, this_cpu, imbalance)) | |
3010 | return sds.busiest; | |
3011 | ||
1e3c88bd PZ |
3012 | if (!sds.busiest || sds.busiest_nr_running == 0) |
3013 | goto out_balanced; | |
3014 | ||
fab47622 NR |
3015 | /* SD_BALANCE_NEWIDLE trumps SMP nice when underutilized */ |
3016 | if (idle == CPU_NEWLY_IDLE && sds.this_has_capacity && | |
3017 | !sds.busiest_has_capacity) | |
3018 | goto force_balance; | |
3019 | ||
1e3c88bd PZ |
3020 | if (sds.this_load >= sds.max_load) |
3021 | goto out_balanced; | |
3022 | ||
3023 | sds.avg_load = (SCHED_LOAD_SCALE * sds.total_load) / sds.total_pwr; | |
3024 | ||
3025 | if (sds.this_load >= sds.avg_load) | |
3026 | goto out_balanced; | |
3027 | ||
3028 | if (100 * sds.max_load <= sd->imbalance_pct * sds.this_load) | |
3029 | goto out_balanced; | |
3030 | ||
fab47622 | 3031 | force_balance: |
1e3c88bd PZ |
3032 | /* Looks like there is an imbalance. Compute it */ |
3033 | calculate_imbalance(&sds, this_cpu, imbalance); | |
3034 | return sds.busiest; | |
3035 | ||
3036 | out_balanced: | |
3037 | /* | |
3038 | * There is no obvious imbalance. But check if we can do some balancing | |
3039 | * to save power. | |
3040 | */ | |
3041 | if (check_power_save_busiest_group(&sds, this_cpu, imbalance)) | |
3042 | return sds.busiest; | |
3043 | ret: | |
3044 | *imbalance = 0; | |
3045 | return NULL; | |
3046 | } | |
3047 | ||
3048 | /* | |
3049 | * find_busiest_queue - find the busiest runqueue among the cpus in group. | |
3050 | */ | |
3051 | static struct rq * | |
9d5efe05 SV |
3052 | find_busiest_queue(struct sched_domain *sd, struct sched_group *group, |
3053 | enum cpu_idle_type idle, unsigned long imbalance, | |
3054 | const struct cpumask *cpus) | |
1e3c88bd PZ |
3055 | { |
3056 | struct rq *busiest = NULL, *rq; | |
3057 | unsigned long max_load = 0; | |
3058 | int i; | |
3059 | ||
3060 | for_each_cpu(i, sched_group_cpus(group)) { | |
3061 | unsigned long power = power_of(i); | |
3062 | unsigned long capacity = DIV_ROUND_CLOSEST(power, SCHED_LOAD_SCALE); | |
3063 | unsigned long wl; | |
3064 | ||
9d5efe05 SV |
3065 | if (!capacity) |
3066 | capacity = fix_small_capacity(sd, group); | |
3067 | ||
1e3c88bd PZ |
3068 | if (!cpumask_test_cpu(i, cpus)) |
3069 | continue; | |
3070 | ||
3071 | rq = cpu_rq(i); | |
6e40f5bb | 3072 | wl = weighted_cpuload(i); |
1e3c88bd | 3073 | |
6e40f5bb TG |
3074 | /* |
3075 | * When comparing with imbalance, use weighted_cpuload() | |
3076 | * which is not scaled with the cpu power. | |
3077 | */ | |
1e3c88bd PZ |
3078 | if (capacity && rq->nr_running == 1 && wl > imbalance) |
3079 | continue; | |
3080 | ||
6e40f5bb TG |
3081 | /* |
3082 | * For the load comparisons with the other cpu's, consider | |
3083 | * the weighted_cpuload() scaled with the cpu power, so that | |
3084 | * the load can be moved away from the cpu that is potentially | |
3085 | * running at a lower capacity. | |
3086 | */ | |
3087 | wl = (wl * SCHED_LOAD_SCALE) / power; | |
3088 | ||
1e3c88bd PZ |
3089 | if (wl > max_load) { |
3090 | max_load = wl; | |
3091 | busiest = rq; | |
3092 | } | |
3093 | } | |
3094 | ||
3095 | return busiest; | |
3096 | } | |
3097 | ||
3098 | /* | |
3099 | * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but | |
3100 | * so long as it is large enough. | |
3101 | */ | |
3102 | #define MAX_PINNED_INTERVAL 512 | |
3103 | ||
3104 | /* Working cpumask for load_balance and load_balance_newidle. */ | |
3105 | static DEFINE_PER_CPU(cpumask_var_t, load_balance_tmpmask); | |
3106 | ||
532cb4c4 MN |
3107 | static int need_active_balance(struct sched_domain *sd, int sd_idle, int idle, |
3108 | int busiest_cpu, int this_cpu) | |
1af3ed3d PZ |
3109 | { |
3110 | if (idle == CPU_NEWLY_IDLE) { | |
532cb4c4 MN |
3111 | |
3112 | /* | |
3113 | * ASYM_PACKING needs to force migrate tasks from busy but | |
3114 | * higher numbered CPUs in order to pack all tasks in the | |
3115 | * lowest numbered CPUs. | |
3116 | */ | |
3117 | if ((sd->flags & SD_ASYM_PACKING) && busiest_cpu > this_cpu) | |
3118 | return 1; | |
3119 | ||
1af3ed3d PZ |
3120 | /* |
3121 | * The only task running in a non-idle cpu can be moved to this | |
3122 | * cpu in an attempt to completely freeup the other CPU | |
3123 | * package. | |
3124 | * | |
3125 | * The package power saving logic comes from | |
3126 | * find_busiest_group(). If there are no imbalance, then | |
3127 | * f_b_g() will return NULL. However when sched_mc={1,2} then | |
3128 | * f_b_g() will select a group from which a running task may be | |
3129 | * pulled to this cpu in order to make the other package idle. | |
3130 | * If there is no opportunity to make a package idle and if | |
3131 | * there are no imbalance, then f_b_g() will return NULL and no | |
3132 | * action will be taken in load_balance_newidle(). | |
3133 | * | |
3134 | * Under normal task pull operation due to imbalance, there | |
3135 | * will be more than one task in the source run queue and | |
3136 | * move_tasks() will succeed. ld_moved will be true and this | |
3137 | * active balance code will not be triggered. | |
3138 | */ | |
3139 | if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && | |
3140 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) | |
3141 | return 0; | |
3142 | ||
3143 | if (sched_mc_power_savings < POWERSAVINGS_BALANCE_WAKEUP) | |
3144 | return 0; | |
3145 | } | |
3146 | ||
3147 | return unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2); | |
3148 | } | |
3149 | ||
969c7921 TH |
3150 | static int active_load_balance_cpu_stop(void *data); |
3151 | ||
1e3c88bd PZ |
3152 | /* |
3153 | * Check this_cpu to ensure it is balanced within domain. Attempt to move | |
3154 | * tasks if there is an imbalance. | |
3155 | */ | |
3156 | static int load_balance(int this_cpu, struct rq *this_rq, | |
3157 | struct sched_domain *sd, enum cpu_idle_type idle, | |
3158 | int *balance) | |
3159 | { | |
3160 | int ld_moved, all_pinned = 0, active_balance = 0, sd_idle = 0; | |
3161 | struct sched_group *group; | |
3162 | unsigned long imbalance; | |
3163 | struct rq *busiest; | |
3164 | unsigned long flags; | |
3165 | struct cpumask *cpus = __get_cpu_var(load_balance_tmpmask); | |
3166 | ||
3167 | cpumask_copy(cpus, cpu_active_mask); | |
3168 | ||
3169 | /* | |
3170 | * When power savings policy is enabled for the parent domain, idle | |
3171 | * sibling can pick up load irrespective of busy siblings. In this case, | |
3172 | * let the state of idle sibling percolate up as CPU_IDLE, instead of | |
3173 | * portraying it as CPU_NOT_IDLE. | |
3174 | */ | |
3175 | if (idle != CPU_NOT_IDLE && sd->flags & SD_SHARE_CPUPOWER && | |
3176 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) | |
3177 | sd_idle = 1; | |
3178 | ||
3179 | schedstat_inc(sd, lb_count[idle]); | |
3180 | ||
3181 | redo: | |
1e3c88bd PZ |
3182 | group = find_busiest_group(sd, this_cpu, &imbalance, idle, &sd_idle, |
3183 | cpus, balance); | |
3184 | ||
3185 | if (*balance == 0) | |
3186 | goto out_balanced; | |
3187 | ||
3188 | if (!group) { | |
3189 | schedstat_inc(sd, lb_nobusyg[idle]); | |
3190 | goto out_balanced; | |
3191 | } | |
3192 | ||
9d5efe05 | 3193 | busiest = find_busiest_queue(sd, group, idle, imbalance, cpus); |
1e3c88bd PZ |
3194 | if (!busiest) { |
3195 | schedstat_inc(sd, lb_nobusyq[idle]); | |
3196 | goto out_balanced; | |
3197 | } | |
3198 | ||
3199 | BUG_ON(busiest == this_rq); | |
3200 | ||
3201 | schedstat_add(sd, lb_imbalance[idle], imbalance); | |
3202 | ||
3203 | ld_moved = 0; | |
3204 | if (busiest->nr_running > 1) { | |
3205 | /* | |
3206 | * Attempt to move tasks. If find_busiest_group has found | |
3207 | * an imbalance but busiest->nr_running <= 1, the group is | |
3208 | * still unbalanced. ld_moved simply stays zero, so it is | |
3209 | * correctly treated as an imbalance. | |
3210 | */ | |
3211 | local_irq_save(flags); | |
3212 | double_rq_lock(this_rq, busiest); | |
3213 | ld_moved = move_tasks(this_rq, this_cpu, busiest, | |
3214 | imbalance, sd, idle, &all_pinned); | |
3215 | double_rq_unlock(this_rq, busiest); | |
3216 | local_irq_restore(flags); | |
3217 | ||
3218 | /* | |
3219 | * some other cpu did the load balance for us. | |
3220 | */ | |
3221 | if (ld_moved && this_cpu != smp_processor_id()) | |
3222 | resched_cpu(this_cpu); | |
3223 | ||
3224 | /* All tasks on this runqueue were pinned by CPU affinity */ | |
3225 | if (unlikely(all_pinned)) { | |
3226 | cpumask_clear_cpu(cpu_of(busiest), cpus); | |
3227 | if (!cpumask_empty(cpus)) | |
3228 | goto redo; | |
3229 | goto out_balanced; | |
3230 | } | |
3231 | } | |
3232 | ||
3233 | if (!ld_moved) { | |
3234 | schedstat_inc(sd, lb_failed[idle]); | |
58b26c4c VP |
3235 | /* |
3236 | * Increment the failure counter only on periodic balance. | |
3237 | * We do not want newidle balance, which can be very | |
3238 | * frequent, pollute the failure counter causing | |
3239 | * excessive cache_hot migrations and active balances. | |
3240 | */ | |
3241 | if (idle != CPU_NEWLY_IDLE) | |
3242 | sd->nr_balance_failed++; | |
1e3c88bd | 3243 | |
532cb4c4 MN |
3244 | if (need_active_balance(sd, sd_idle, idle, cpu_of(busiest), |
3245 | this_cpu)) { | |
1e3c88bd PZ |
3246 | raw_spin_lock_irqsave(&busiest->lock, flags); |
3247 | ||
969c7921 TH |
3248 | /* don't kick the active_load_balance_cpu_stop, |
3249 | * if the curr task on busiest cpu can't be | |
3250 | * moved to this_cpu | |
1e3c88bd PZ |
3251 | */ |
3252 | if (!cpumask_test_cpu(this_cpu, | |
3253 | &busiest->curr->cpus_allowed)) { | |
3254 | raw_spin_unlock_irqrestore(&busiest->lock, | |
3255 | flags); | |
3256 | all_pinned = 1; | |
3257 | goto out_one_pinned; | |
3258 | } | |
3259 | ||
969c7921 TH |
3260 | /* |
3261 | * ->active_balance synchronizes accesses to | |
3262 | * ->active_balance_work. Once set, it's cleared | |
3263 | * only after active load balance is finished. | |
3264 | */ | |
1e3c88bd PZ |
3265 | if (!busiest->active_balance) { |
3266 | busiest->active_balance = 1; | |
3267 | busiest->push_cpu = this_cpu; | |
3268 | active_balance = 1; | |
3269 | } | |
3270 | raw_spin_unlock_irqrestore(&busiest->lock, flags); | |
969c7921 | 3271 | |
1e3c88bd | 3272 | if (active_balance) |
969c7921 TH |
3273 | stop_one_cpu_nowait(cpu_of(busiest), |
3274 | active_load_balance_cpu_stop, busiest, | |
3275 | &busiest->active_balance_work); | |
1e3c88bd PZ |
3276 | |
3277 | /* | |
3278 | * We've kicked active balancing, reset the failure | |
3279 | * counter. | |
3280 | */ | |
3281 | sd->nr_balance_failed = sd->cache_nice_tries+1; | |
3282 | } | |
3283 | } else | |
3284 | sd->nr_balance_failed = 0; | |
3285 | ||
3286 | if (likely(!active_balance)) { | |
3287 | /* We were unbalanced, so reset the balancing interval */ | |
3288 | sd->balance_interval = sd->min_interval; | |
3289 | } else { | |
3290 | /* | |
3291 | * If we've begun active balancing, start to back off. This | |
3292 | * case may not be covered by the all_pinned logic if there | |
3293 | * is only 1 task on the busy runqueue (because we don't call | |
3294 | * move_tasks). | |
3295 | */ | |
3296 | if (sd->balance_interval < sd->max_interval) | |
3297 | sd->balance_interval *= 2; | |
3298 | } | |
3299 | ||
3300 | if (!ld_moved && !sd_idle && sd->flags & SD_SHARE_CPUPOWER && | |
3301 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) | |
3302 | ld_moved = -1; | |
3303 | ||
3304 | goto out; | |
3305 | ||
3306 | out_balanced: | |
3307 | schedstat_inc(sd, lb_balanced[idle]); | |
3308 | ||
3309 | sd->nr_balance_failed = 0; | |
3310 | ||
3311 | out_one_pinned: | |
3312 | /* tune up the balancing interval */ | |
3313 | if ((all_pinned && sd->balance_interval < MAX_PINNED_INTERVAL) || | |
3314 | (sd->balance_interval < sd->max_interval)) | |
3315 | sd->balance_interval *= 2; | |
3316 | ||
3317 | if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && | |
3318 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) | |
3319 | ld_moved = -1; | |
3320 | else | |
3321 | ld_moved = 0; | |
3322 | out: | |
1e3c88bd PZ |
3323 | return ld_moved; |
3324 | } | |
3325 | ||
1e3c88bd PZ |
3326 | /* |
3327 | * idle_balance is called by schedule() if this_cpu is about to become | |
3328 | * idle. Attempts to pull tasks from other CPUs. | |
3329 | */ | |
3330 | static void idle_balance(int this_cpu, struct rq *this_rq) | |
3331 | { | |
3332 | struct sched_domain *sd; | |
3333 | int pulled_task = 0; | |
3334 | unsigned long next_balance = jiffies + HZ; | |
3335 | ||
3336 | this_rq->idle_stamp = this_rq->clock; | |
3337 | ||
3338 | if (this_rq->avg_idle < sysctl_sched_migration_cost) | |
3339 | return; | |
3340 | ||
f492e12e PZ |
3341 | /* |
3342 | * Drop the rq->lock, but keep IRQ/preempt disabled. | |
3343 | */ | |
3344 | raw_spin_unlock(&this_rq->lock); | |
3345 | ||
1e3c88bd PZ |
3346 | for_each_domain(this_cpu, sd) { |
3347 | unsigned long interval; | |
f492e12e | 3348 | int balance = 1; |
1e3c88bd PZ |
3349 | |
3350 | if (!(sd->flags & SD_LOAD_BALANCE)) | |
3351 | continue; | |
3352 | ||
f492e12e | 3353 | if (sd->flags & SD_BALANCE_NEWIDLE) { |
1e3c88bd | 3354 | /* If we've pulled tasks over stop searching: */ |
f492e12e PZ |
3355 | pulled_task = load_balance(this_cpu, this_rq, |
3356 | sd, CPU_NEWLY_IDLE, &balance); | |
3357 | } | |
1e3c88bd PZ |
3358 | |
3359 | interval = msecs_to_jiffies(sd->balance_interval); | |
3360 | if (time_after(next_balance, sd->last_balance + interval)) | |
3361 | next_balance = sd->last_balance + interval; | |
fab47622 | 3362 | if (pulled_task) |
1e3c88bd | 3363 | break; |
1e3c88bd | 3364 | } |
f492e12e PZ |
3365 | |
3366 | raw_spin_lock(&this_rq->lock); | |
3367 | ||
1e3c88bd PZ |
3368 | if (pulled_task || time_after(jiffies, this_rq->next_balance)) { |
3369 | /* | |
3370 | * We are going idle. next_balance may be set based on | |
3371 | * a busy processor. So reset next_balance. | |
3372 | */ | |
3373 | this_rq->next_balance = next_balance; | |
3374 | } | |
3375 | } | |
3376 | ||
3377 | /* | |
969c7921 TH |
3378 | * active_load_balance_cpu_stop is run by cpu stopper. It pushes |
3379 | * running tasks off the busiest CPU onto idle CPUs. It requires at | |
3380 | * least 1 task to be running on each physical CPU where possible, and | |
3381 | * avoids physical / logical imbalances. | |
1e3c88bd | 3382 | */ |
969c7921 | 3383 | static int active_load_balance_cpu_stop(void *data) |
1e3c88bd | 3384 | { |
969c7921 TH |
3385 | struct rq *busiest_rq = data; |
3386 | int busiest_cpu = cpu_of(busiest_rq); | |
1e3c88bd | 3387 | int target_cpu = busiest_rq->push_cpu; |
969c7921 | 3388 | struct rq *target_rq = cpu_rq(target_cpu); |
1e3c88bd | 3389 | struct sched_domain *sd; |
969c7921 TH |
3390 | |
3391 | raw_spin_lock_irq(&busiest_rq->lock); | |
3392 | ||
3393 | /* make sure the requested cpu hasn't gone down in the meantime */ | |
3394 | if (unlikely(busiest_cpu != smp_processor_id() || | |
3395 | !busiest_rq->active_balance)) | |
3396 | goto out_unlock; | |
1e3c88bd PZ |
3397 | |
3398 | /* Is there any task to move? */ | |
3399 | if (busiest_rq->nr_running <= 1) | |
969c7921 | 3400 | goto out_unlock; |
1e3c88bd PZ |
3401 | |
3402 | /* | |
3403 | * This condition is "impossible", if it occurs | |
3404 | * we need to fix it. Originally reported by | |
3405 | * Bjorn Helgaas on a 128-cpu setup. | |
3406 | */ | |
3407 | BUG_ON(busiest_rq == target_rq); | |
3408 | ||
3409 | /* move a task from busiest_rq to target_rq */ | |
3410 | double_lock_balance(busiest_rq, target_rq); | |
1e3c88bd PZ |
3411 | |
3412 | /* Search for an sd spanning us and the target CPU. */ | |
3413 | for_each_domain(target_cpu, sd) { | |
3414 | if ((sd->flags & SD_LOAD_BALANCE) && | |
3415 | cpumask_test_cpu(busiest_cpu, sched_domain_span(sd))) | |
3416 | break; | |
3417 | } | |
3418 | ||
3419 | if (likely(sd)) { | |
3420 | schedstat_inc(sd, alb_count); | |
3421 | ||
3422 | if (move_one_task(target_rq, target_cpu, busiest_rq, | |
3423 | sd, CPU_IDLE)) | |
3424 | schedstat_inc(sd, alb_pushed); | |
3425 | else | |
3426 | schedstat_inc(sd, alb_failed); | |
3427 | } | |
3428 | double_unlock_balance(busiest_rq, target_rq); | |
969c7921 TH |
3429 | out_unlock: |
3430 | busiest_rq->active_balance = 0; | |
3431 | raw_spin_unlock_irq(&busiest_rq->lock); | |
3432 | return 0; | |
1e3c88bd PZ |
3433 | } |
3434 | ||
3435 | #ifdef CONFIG_NO_HZ | |
83cd4fe2 VP |
3436 | |
3437 | static DEFINE_PER_CPU(struct call_single_data, remote_sched_softirq_cb); | |
3438 | ||
3439 | static void trigger_sched_softirq(void *data) | |
3440 | { | |
3441 | raise_softirq_irqoff(SCHED_SOFTIRQ); | |
3442 | } | |
3443 | ||
3444 | static inline void init_sched_softirq_csd(struct call_single_data *csd) | |
3445 | { | |
3446 | csd->func = trigger_sched_softirq; | |
3447 | csd->info = NULL; | |
3448 | csd->flags = 0; | |
3449 | csd->priv = 0; | |
3450 | } | |
3451 | ||
3452 | /* | |
3453 | * idle load balancing details | |
3454 | * - One of the idle CPUs nominates itself as idle load_balancer, while | |
3455 | * entering idle. | |
3456 | * - This idle load balancer CPU will also go into tickless mode when | |
3457 | * it is idle, just like all other idle CPUs | |
3458 | * - When one of the busy CPUs notice that there may be an idle rebalancing | |
3459 | * needed, they will kick the idle load balancer, which then does idle | |
3460 | * load balancing for all the idle CPUs. | |
3461 | */ | |
1e3c88bd PZ |
3462 | static struct { |
3463 | atomic_t load_balancer; | |
83cd4fe2 VP |
3464 | atomic_t first_pick_cpu; |
3465 | atomic_t second_pick_cpu; | |
3466 | cpumask_var_t idle_cpus_mask; | |
3467 | cpumask_var_t grp_idle_mask; | |
3468 | unsigned long next_balance; /* in jiffy units */ | |
3469 | } nohz ____cacheline_aligned; | |
1e3c88bd PZ |
3470 | |
3471 | int get_nohz_load_balancer(void) | |
3472 | { | |
3473 | return atomic_read(&nohz.load_balancer); | |
3474 | } | |
3475 | ||
3476 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) | |
3477 | /** | |
3478 | * lowest_flag_domain - Return lowest sched_domain containing flag. | |
3479 | * @cpu: The cpu whose lowest level of sched domain is to | |
3480 | * be returned. | |
3481 | * @flag: The flag to check for the lowest sched_domain | |
3482 | * for the given cpu. | |
3483 | * | |
3484 | * Returns the lowest sched_domain of a cpu which contains the given flag. | |
3485 | */ | |
3486 | static inline struct sched_domain *lowest_flag_domain(int cpu, int flag) | |
3487 | { | |
3488 | struct sched_domain *sd; | |
3489 | ||
3490 | for_each_domain(cpu, sd) | |
3491 | if (sd && (sd->flags & flag)) | |
3492 | break; | |
3493 | ||
3494 | return sd; | |
3495 | } | |
3496 | ||
3497 | /** | |
3498 | * for_each_flag_domain - Iterates over sched_domains containing the flag. | |
3499 | * @cpu: The cpu whose domains we're iterating over. | |
3500 | * @sd: variable holding the value of the power_savings_sd | |
3501 | * for cpu. | |
3502 | * @flag: The flag to filter the sched_domains to be iterated. | |
3503 | * | |
3504 | * Iterates over all the scheduler domains for a given cpu that has the 'flag' | |
3505 | * set, starting from the lowest sched_domain to the highest. | |
3506 | */ | |
3507 | #define for_each_flag_domain(cpu, sd, flag) \ | |
3508 | for (sd = lowest_flag_domain(cpu, flag); \ | |
3509 | (sd && (sd->flags & flag)); sd = sd->parent) | |
3510 | ||
3511 | /** | |
3512 | * is_semi_idle_group - Checks if the given sched_group is semi-idle. | |
3513 | * @ilb_group: group to be checked for semi-idleness | |
3514 | * | |
3515 | * Returns: 1 if the group is semi-idle. 0 otherwise. | |
3516 | * | |
3517 | * We define a sched_group to be semi idle if it has atleast one idle-CPU | |
3518 | * and atleast one non-idle CPU. This helper function checks if the given | |
3519 | * sched_group is semi-idle or not. | |
3520 | */ | |
3521 | static inline int is_semi_idle_group(struct sched_group *ilb_group) | |
3522 | { | |
83cd4fe2 | 3523 | cpumask_and(nohz.grp_idle_mask, nohz.idle_cpus_mask, |
1e3c88bd PZ |
3524 | sched_group_cpus(ilb_group)); |
3525 | ||
3526 | /* | |
3527 | * A sched_group is semi-idle when it has atleast one busy cpu | |
3528 | * and atleast one idle cpu. | |
3529 | */ | |
83cd4fe2 | 3530 | if (cpumask_empty(nohz.grp_idle_mask)) |
1e3c88bd PZ |
3531 | return 0; |
3532 | ||
83cd4fe2 | 3533 | if (cpumask_equal(nohz.grp_idle_mask, sched_group_cpus(ilb_group))) |
1e3c88bd PZ |
3534 | return 0; |
3535 | ||
3536 | return 1; | |
3537 | } | |
3538 | /** | |
3539 | * find_new_ilb - Finds the optimum idle load balancer for nomination. | |
3540 | * @cpu: The cpu which is nominating a new idle_load_balancer. | |
3541 | * | |
3542 | * Returns: Returns the id of the idle load balancer if it exists, | |
3543 | * Else, returns >= nr_cpu_ids. | |
3544 | * | |
3545 | * This algorithm picks the idle load balancer such that it belongs to a | |
3546 | * semi-idle powersavings sched_domain. The idea is to try and avoid | |
3547 | * completely idle packages/cores just for the purpose of idle load balancing | |
3548 | * when there are other idle cpu's which are better suited for that job. | |
3549 | */ | |
3550 | static int find_new_ilb(int cpu) | |
3551 | { | |
3552 | struct sched_domain *sd; | |
3553 | struct sched_group *ilb_group; | |
3554 | ||
3555 | /* | |
3556 | * Have idle load balancer selection from semi-idle packages only | |
3557 | * when power-aware load balancing is enabled | |
3558 | */ | |
3559 | if (!(sched_smt_power_savings || sched_mc_power_savings)) | |
3560 | goto out_done; | |
3561 | ||
3562 | /* | |
3563 | * Optimize for the case when we have no idle CPUs or only one | |
3564 | * idle CPU. Don't walk the sched_domain hierarchy in such cases | |
3565 | */ | |
83cd4fe2 | 3566 | if (cpumask_weight(nohz.idle_cpus_mask) < 2) |
1e3c88bd PZ |
3567 | goto out_done; |
3568 | ||
3569 | for_each_flag_domain(cpu, sd, SD_POWERSAVINGS_BALANCE) { | |
3570 | ilb_group = sd->groups; | |
3571 | ||
3572 | do { | |
3573 | if (is_semi_idle_group(ilb_group)) | |
83cd4fe2 | 3574 | return cpumask_first(nohz.grp_idle_mask); |
1e3c88bd PZ |
3575 | |
3576 | ilb_group = ilb_group->next; | |
3577 | ||
3578 | } while (ilb_group != sd->groups); | |
3579 | } | |
3580 | ||
3581 | out_done: | |
83cd4fe2 | 3582 | return nr_cpu_ids; |
1e3c88bd PZ |
3583 | } |
3584 | #else /* (CONFIG_SCHED_MC || CONFIG_SCHED_SMT) */ | |
3585 | static inline int find_new_ilb(int call_cpu) | |
3586 | { | |
83cd4fe2 | 3587 | return nr_cpu_ids; |
1e3c88bd PZ |
3588 | } |
3589 | #endif | |
3590 | ||
83cd4fe2 VP |
3591 | /* |
3592 | * Kick a CPU to do the nohz balancing, if it is time for it. We pick the | |
3593 | * nohz_load_balancer CPU (if there is one) otherwise fallback to any idle | |
3594 | * CPU (if there is one). | |
3595 | */ | |
3596 | static void nohz_balancer_kick(int cpu) | |
3597 | { | |
3598 | int ilb_cpu; | |
3599 | ||
3600 | nohz.next_balance++; | |
3601 | ||
3602 | ilb_cpu = get_nohz_load_balancer(); | |
3603 | ||
3604 | if (ilb_cpu >= nr_cpu_ids) { | |
3605 | ilb_cpu = cpumask_first(nohz.idle_cpus_mask); | |
3606 | if (ilb_cpu >= nr_cpu_ids) | |
3607 | return; | |
3608 | } | |
3609 | ||
3610 | if (!cpu_rq(ilb_cpu)->nohz_balance_kick) { | |
3611 | struct call_single_data *cp; | |
3612 | ||
3613 | cpu_rq(ilb_cpu)->nohz_balance_kick = 1; | |
3614 | cp = &per_cpu(remote_sched_softirq_cb, cpu); | |
3615 | __smp_call_function_single(ilb_cpu, cp, 0); | |
3616 | } | |
3617 | return; | |
3618 | } | |
3619 | ||
1e3c88bd PZ |
3620 | /* |
3621 | * This routine will try to nominate the ilb (idle load balancing) | |
3622 | * owner among the cpus whose ticks are stopped. ilb owner will do the idle | |
83cd4fe2 | 3623 | * load balancing on behalf of all those cpus. |
1e3c88bd | 3624 | * |
83cd4fe2 VP |
3625 | * When the ilb owner becomes busy, we will not have new ilb owner until some |
3626 | * idle CPU wakes up and goes back to idle or some busy CPU tries to kick | |
3627 | * idle load balancing by kicking one of the idle CPUs. | |
1e3c88bd | 3628 | * |
83cd4fe2 VP |
3629 | * Ticks are stopped for the ilb owner as well, with busy CPU kicking this |
3630 | * ilb owner CPU in future (when there is a need for idle load balancing on | |
3631 | * behalf of all idle CPUs). | |
1e3c88bd | 3632 | */ |
83cd4fe2 | 3633 | void select_nohz_load_balancer(int stop_tick) |
1e3c88bd PZ |
3634 | { |
3635 | int cpu = smp_processor_id(); | |
3636 | ||
3637 | if (stop_tick) { | |
1e3c88bd PZ |
3638 | if (!cpu_active(cpu)) { |
3639 | if (atomic_read(&nohz.load_balancer) != cpu) | |
83cd4fe2 | 3640 | return; |
1e3c88bd PZ |
3641 | |
3642 | /* | |
3643 | * If we are going offline and still the leader, | |
3644 | * give up! | |
3645 | */ | |
83cd4fe2 VP |
3646 | if (atomic_cmpxchg(&nohz.load_balancer, cpu, |
3647 | nr_cpu_ids) != cpu) | |
1e3c88bd PZ |
3648 | BUG(); |
3649 | ||
83cd4fe2 | 3650 | return; |
1e3c88bd PZ |
3651 | } |
3652 | ||
83cd4fe2 | 3653 | cpumask_set_cpu(cpu, nohz.idle_cpus_mask); |
1e3c88bd | 3654 | |
83cd4fe2 VP |
3655 | if (atomic_read(&nohz.first_pick_cpu) == cpu) |
3656 | atomic_cmpxchg(&nohz.first_pick_cpu, cpu, nr_cpu_ids); | |
3657 | if (atomic_read(&nohz.second_pick_cpu) == cpu) | |
3658 | atomic_cmpxchg(&nohz.second_pick_cpu, cpu, nr_cpu_ids); | |
1e3c88bd | 3659 | |
83cd4fe2 | 3660 | if (atomic_read(&nohz.load_balancer) >= nr_cpu_ids) { |
1e3c88bd PZ |
3661 | int new_ilb; |
3662 | ||
83cd4fe2 VP |
3663 | /* make me the ilb owner */ |
3664 | if (atomic_cmpxchg(&nohz.load_balancer, nr_cpu_ids, | |
3665 | cpu) != nr_cpu_ids) | |
3666 | return; | |
3667 | ||
1e3c88bd PZ |
3668 | /* |
3669 | * Check to see if there is a more power-efficient | |
3670 | * ilb. | |
3671 | */ | |
3672 | new_ilb = find_new_ilb(cpu); | |
3673 | if (new_ilb < nr_cpu_ids && new_ilb != cpu) { | |
83cd4fe2 | 3674 | atomic_set(&nohz.load_balancer, nr_cpu_ids); |
1e3c88bd | 3675 | resched_cpu(new_ilb); |
83cd4fe2 | 3676 | return; |
1e3c88bd | 3677 | } |
83cd4fe2 | 3678 | return; |
1e3c88bd PZ |
3679 | } |
3680 | } else { | |
83cd4fe2 VP |
3681 | if (!cpumask_test_cpu(cpu, nohz.idle_cpus_mask)) |
3682 | return; | |
1e3c88bd | 3683 | |
83cd4fe2 | 3684 | cpumask_clear_cpu(cpu, nohz.idle_cpus_mask); |
1e3c88bd PZ |
3685 | |
3686 | if (atomic_read(&nohz.load_balancer) == cpu) | |
83cd4fe2 VP |
3687 | if (atomic_cmpxchg(&nohz.load_balancer, cpu, |
3688 | nr_cpu_ids) != cpu) | |
1e3c88bd PZ |
3689 | BUG(); |
3690 | } | |
83cd4fe2 | 3691 | return; |
1e3c88bd PZ |
3692 | } |
3693 | #endif | |
3694 | ||
3695 | static DEFINE_SPINLOCK(balancing); | |
3696 | ||
3697 | /* | |
3698 | * It checks each scheduling domain to see if it is due to be balanced, | |
3699 | * and initiates a balancing operation if so. | |
3700 | * | |
3701 | * Balancing parameters are set up in arch_init_sched_domains. | |
3702 | */ | |
3703 | static void rebalance_domains(int cpu, enum cpu_idle_type idle) | |
3704 | { | |
3705 | int balance = 1; | |
3706 | struct rq *rq = cpu_rq(cpu); | |
3707 | unsigned long interval; | |
3708 | struct sched_domain *sd; | |
3709 | /* Earliest time when we have to do rebalance again */ | |
3710 | unsigned long next_balance = jiffies + 60*HZ; | |
3711 | int update_next_balance = 0; | |
3712 | int need_serialize; | |
3713 | ||
2069dd75 PZ |
3714 | update_shares(cpu); |
3715 | ||
1e3c88bd PZ |
3716 | for_each_domain(cpu, sd) { |
3717 | if (!(sd->flags & SD_LOAD_BALANCE)) | |
3718 | continue; | |
3719 | ||
3720 | interval = sd->balance_interval; | |
3721 | if (idle != CPU_IDLE) | |
3722 | interval *= sd->busy_factor; | |
3723 | ||
3724 | /* scale ms to jiffies */ | |
3725 | interval = msecs_to_jiffies(interval); | |
3726 | if (unlikely(!interval)) | |
3727 | interval = 1; | |
3728 | if (interval > HZ*NR_CPUS/10) | |
3729 | interval = HZ*NR_CPUS/10; | |
3730 | ||
3731 | need_serialize = sd->flags & SD_SERIALIZE; | |
3732 | ||
3733 | if (need_serialize) { | |
3734 | if (!spin_trylock(&balancing)) | |
3735 | goto out; | |
3736 | } | |
3737 | ||
3738 | if (time_after_eq(jiffies, sd->last_balance + interval)) { | |
3739 | if (load_balance(cpu, rq, sd, idle, &balance)) { | |
3740 | /* | |
3741 | * We've pulled tasks over so either we're no | |
3742 | * longer idle, or one of our SMT siblings is | |
3743 | * not idle. | |
3744 | */ | |
3745 | idle = CPU_NOT_IDLE; | |
3746 | } | |
3747 | sd->last_balance = jiffies; | |
3748 | } | |
3749 | if (need_serialize) | |
3750 | spin_unlock(&balancing); | |
3751 | out: | |
3752 | if (time_after(next_balance, sd->last_balance + interval)) { | |
3753 | next_balance = sd->last_balance + interval; | |
3754 | update_next_balance = 1; | |
3755 | } | |
3756 | ||
3757 | /* | |
3758 | * Stop the load balance at this level. There is another | |
3759 | * CPU in our sched group which is doing load balancing more | |
3760 | * actively. | |
3761 | */ | |
3762 | if (!balance) | |
3763 | break; | |
3764 | } | |
3765 | ||
3766 | /* | |
3767 | * next_balance will be updated only when there is a need. | |
3768 | * When the cpu is attached to null domain for ex, it will not be | |
3769 | * updated. | |
3770 | */ | |
3771 | if (likely(update_next_balance)) | |
3772 | rq->next_balance = next_balance; | |
3773 | } | |
3774 | ||
83cd4fe2 | 3775 | #ifdef CONFIG_NO_HZ |
1e3c88bd | 3776 | /* |
83cd4fe2 | 3777 | * In CONFIG_NO_HZ case, the idle balance kickee will do the |
1e3c88bd PZ |
3778 | * rebalancing for all the cpus for whom scheduler ticks are stopped. |
3779 | */ | |
83cd4fe2 VP |
3780 | static void nohz_idle_balance(int this_cpu, enum cpu_idle_type idle) |
3781 | { | |
3782 | struct rq *this_rq = cpu_rq(this_cpu); | |
3783 | struct rq *rq; | |
3784 | int balance_cpu; | |
3785 | ||
3786 | if (idle != CPU_IDLE || !this_rq->nohz_balance_kick) | |
3787 | return; | |
3788 | ||
3789 | for_each_cpu(balance_cpu, nohz.idle_cpus_mask) { | |
3790 | if (balance_cpu == this_cpu) | |
3791 | continue; | |
3792 | ||
3793 | /* | |
3794 | * If this cpu gets work to do, stop the load balancing | |
3795 | * work being done for other cpus. Next load | |
3796 | * balancing owner will pick it up. | |
3797 | */ | |
3798 | if (need_resched()) { | |
3799 | this_rq->nohz_balance_kick = 0; | |
3800 | break; | |
3801 | } | |
3802 | ||
3803 | raw_spin_lock_irq(&this_rq->lock); | |
5343bdb8 | 3804 | update_rq_clock(this_rq); |
83cd4fe2 VP |
3805 | update_cpu_load(this_rq); |
3806 | raw_spin_unlock_irq(&this_rq->lock); | |
3807 | ||
3808 | rebalance_domains(balance_cpu, CPU_IDLE); | |
3809 | ||
3810 | rq = cpu_rq(balance_cpu); | |
3811 | if (time_after(this_rq->next_balance, rq->next_balance)) | |
3812 | this_rq->next_balance = rq->next_balance; | |
3813 | } | |
3814 | nohz.next_balance = this_rq->next_balance; | |
3815 | this_rq->nohz_balance_kick = 0; | |
3816 | } | |
3817 | ||
3818 | /* | |
3819 | * Current heuristic for kicking the idle load balancer | |
3820 | * - first_pick_cpu is the one of the busy CPUs. It will kick | |
3821 | * idle load balancer when it has more than one process active. This | |
3822 | * eliminates the need for idle load balancing altogether when we have | |
3823 | * only one running process in the system (common case). | |
3824 | * - If there are more than one busy CPU, idle load balancer may have | |
3825 | * to run for active_load_balance to happen (i.e., two busy CPUs are | |
3826 | * SMT or core siblings and can run better if they move to different | |
3827 | * physical CPUs). So, second_pick_cpu is the second of the busy CPUs | |
3828 | * which will kick idle load balancer as soon as it has any load. | |
3829 | */ | |
3830 | static inline int nohz_kick_needed(struct rq *rq, int cpu) | |
3831 | { | |
3832 | unsigned long now = jiffies; | |
3833 | int ret; | |
3834 | int first_pick_cpu, second_pick_cpu; | |
3835 | ||
3836 | if (time_before(now, nohz.next_balance)) | |
3837 | return 0; | |
3838 | ||
f6c3f168 | 3839 | if (rq->idle_at_tick) |
83cd4fe2 VP |
3840 | return 0; |
3841 | ||
3842 | first_pick_cpu = atomic_read(&nohz.first_pick_cpu); | |
3843 | second_pick_cpu = atomic_read(&nohz.second_pick_cpu); | |
3844 | ||
3845 | if (first_pick_cpu < nr_cpu_ids && first_pick_cpu != cpu && | |
3846 | second_pick_cpu < nr_cpu_ids && second_pick_cpu != cpu) | |
3847 | return 0; | |
3848 | ||
3849 | ret = atomic_cmpxchg(&nohz.first_pick_cpu, nr_cpu_ids, cpu); | |
3850 | if (ret == nr_cpu_ids || ret == cpu) { | |
3851 | atomic_cmpxchg(&nohz.second_pick_cpu, cpu, nr_cpu_ids); | |
3852 | if (rq->nr_running > 1) | |
3853 | return 1; | |
3854 | } else { | |
3855 | ret = atomic_cmpxchg(&nohz.second_pick_cpu, nr_cpu_ids, cpu); | |
3856 | if (ret == nr_cpu_ids || ret == cpu) { | |
3857 | if (rq->nr_running) | |
3858 | return 1; | |
3859 | } | |
3860 | } | |
3861 | return 0; | |
3862 | } | |
3863 | #else | |
3864 | static void nohz_idle_balance(int this_cpu, enum cpu_idle_type idle) { } | |
3865 | #endif | |
3866 | ||
3867 | /* | |
3868 | * run_rebalance_domains is triggered when needed from the scheduler tick. | |
3869 | * Also triggered for nohz idle balancing (with nohz_balancing_kick set). | |
3870 | */ | |
1e3c88bd PZ |
3871 | static void run_rebalance_domains(struct softirq_action *h) |
3872 | { | |
3873 | int this_cpu = smp_processor_id(); | |
3874 | struct rq *this_rq = cpu_rq(this_cpu); | |
3875 | enum cpu_idle_type idle = this_rq->idle_at_tick ? | |
3876 | CPU_IDLE : CPU_NOT_IDLE; | |
3877 | ||
3878 | rebalance_domains(this_cpu, idle); | |
3879 | ||
1e3c88bd | 3880 | /* |
83cd4fe2 | 3881 | * If this cpu has a pending nohz_balance_kick, then do the |
1e3c88bd PZ |
3882 | * balancing on behalf of the other idle cpus whose ticks are |
3883 | * stopped. | |
3884 | */ | |
83cd4fe2 | 3885 | nohz_idle_balance(this_cpu, idle); |
1e3c88bd PZ |
3886 | } |
3887 | ||
3888 | static inline int on_null_domain(int cpu) | |
3889 | { | |
90a6501f | 3890 | return !rcu_dereference_sched(cpu_rq(cpu)->sd); |
1e3c88bd PZ |
3891 | } |
3892 | ||
3893 | /* | |
3894 | * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing. | |
1e3c88bd PZ |
3895 | */ |
3896 | static inline void trigger_load_balance(struct rq *rq, int cpu) | |
3897 | { | |
1e3c88bd PZ |
3898 | /* Don't need to rebalance while attached to NULL domain */ |
3899 | if (time_after_eq(jiffies, rq->next_balance) && | |
3900 | likely(!on_null_domain(cpu))) | |
3901 | raise_softirq(SCHED_SOFTIRQ); | |
83cd4fe2 VP |
3902 | #ifdef CONFIG_NO_HZ |
3903 | else if (nohz_kick_needed(rq, cpu) && likely(!on_null_domain(cpu))) | |
3904 | nohz_balancer_kick(cpu); | |
3905 | #endif | |
1e3c88bd PZ |
3906 | } |
3907 | ||
0bcdcf28 CE |
3908 | static void rq_online_fair(struct rq *rq) |
3909 | { | |
3910 | update_sysctl(); | |
3911 | } | |
3912 | ||
3913 | static void rq_offline_fair(struct rq *rq) | |
3914 | { | |
3915 | update_sysctl(); | |
3916 | } | |
3917 | ||
1e3c88bd PZ |
3918 | #else /* CONFIG_SMP */ |
3919 | ||
3920 | /* | |
3921 | * on UP we do not need to balance between CPUs: | |
3922 | */ | |
3923 | static inline void idle_balance(int cpu, struct rq *rq) | |
3924 | { | |
3925 | } | |
3926 | ||
55e12e5e | 3927 | #endif /* CONFIG_SMP */ |
e1d1484f | 3928 | |
bf0f6f24 IM |
3929 | /* |
3930 | * scheduler tick hitting a task of our scheduling class: | |
3931 | */ | |
8f4d37ec | 3932 | static void task_tick_fair(struct rq *rq, struct task_struct *curr, int queued) |
bf0f6f24 IM |
3933 | { |
3934 | struct cfs_rq *cfs_rq; | |
3935 | struct sched_entity *se = &curr->se; | |
3936 | ||
3937 | for_each_sched_entity(se) { | |
3938 | cfs_rq = cfs_rq_of(se); | |
8f4d37ec | 3939 | entity_tick(cfs_rq, se, queued); |
bf0f6f24 IM |
3940 | } |
3941 | } | |
3942 | ||
3943 | /* | |
cd29fe6f PZ |
3944 | * called on fork with the child task as argument from the parent's context |
3945 | * - child not yet on the tasklist | |
3946 | * - preemption disabled | |
bf0f6f24 | 3947 | */ |
cd29fe6f | 3948 | static void task_fork_fair(struct task_struct *p) |
bf0f6f24 | 3949 | { |
cd29fe6f | 3950 | struct cfs_rq *cfs_rq = task_cfs_rq(current); |
429d43bc | 3951 | struct sched_entity *se = &p->se, *curr = cfs_rq->curr; |
00bf7bfc | 3952 | int this_cpu = smp_processor_id(); |
cd29fe6f PZ |
3953 | struct rq *rq = this_rq(); |
3954 | unsigned long flags; | |
3955 | ||
05fa785c | 3956 | raw_spin_lock_irqsave(&rq->lock, flags); |
bf0f6f24 | 3957 | |
861d034e PZ |
3958 | update_rq_clock(rq); |
3959 | ||
b0a0f667 PM |
3960 | if (unlikely(task_cpu(p) != this_cpu)) { |
3961 | rcu_read_lock(); | |
cd29fe6f | 3962 | __set_task_cpu(p, this_cpu); |
b0a0f667 PM |
3963 | rcu_read_unlock(); |
3964 | } | |
bf0f6f24 | 3965 | |
7109c442 | 3966 | update_curr(cfs_rq); |
cd29fe6f | 3967 | |
b5d9d734 MG |
3968 | if (curr) |
3969 | se->vruntime = curr->vruntime; | |
aeb73b04 | 3970 | place_entity(cfs_rq, se, 1); |
4d78e7b6 | 3971 | |
cd29fe6f | 3972 | if (sysctl_sched_child_runs_first && curr && entity_before(curr, se)) { |
87fefa38 | 3973 | /* |
edcb60a3 IM |
3974 | * Upon rescheduling, sched_class::put_prev_task() will place |
3975 | * 'current' within the tree based on its new key value. | |
3976 | */ | |
4d78e7b6 | 3977 | swap(curr->vruntime, se->vruntime); |
aec0a514 | 3978 | resched_task(rq->curr); |
4d78e7b6 | 3979 | } |
bf0f6f24 | 3980 | |
88ec22d3 PZ |
3981 | se->vruntime -= cfs_rq->min_vruntime; |
3982 | ||
05fa785c | 3983 | raw_spin_unlock_irqrestore(&rq->lock, flags); |
bf0f6f24 IM |
3984 | } |
3985 | ||
cb469845 SR |
3986 | /* |
3987 | * Priority of the task has changed. Check to see if we preempt | |
3988 | * the current task. | |
3989 | */ | |
3990 | static void prio_changed_fair(struct rq *rq, struct task_struct *p, | |
3991 | int oldprio, int running) | |
3992 | { | |
3993 | /* | |
3994 | * Reschedule if we are currently running on this runqueue and | |
3995 | * our priority decreased, or if we are not currently running on | |
3996 | * this runqueue and our priority is higher than the current's | |
3997 | */ | |
3998 | if (running) { | |
3999 | if (p->prio > oldprio) | |
4000 | resched_task(rq->curr); | |
4001 | } else | |
15afe09b | 4002 | check_preempt_curr(rq, p, 0); |
cb469845 SR |
4003 | } |
4004 | ||
4005 | /* | |
4006 | * We switched to the sched_fair class. | |
4007 | */ | |
4008 | static void switched_to_fair(struct rq *rq, struct task_struct *p, | |
4009 | int running) | |
4010 | { | |
4011 | /* | |
4012 | * We were most likely switched from sched_rt, so | |
4013 | * kick off the schedule if running, otherwise just see | |
4014 | * if we can still preempt the current task. | |
4015 | */ | |
4016 | if (running) | |
4017 | resched_task(rq->curr); | |
4018 | else | |
15afe09b | 4019 | check_preempt_curr(rq, p, 0); |
cb469845 SR |
4020 | } |
4021 | ||
83b699ed SV |
4022 | /* Account for a task changing its policy or group. |
4023 | * | |
4024 | * This routine is mostly called to set cfs_rq->curr field when a task | |
4025 | * migrates between groups/classes. | |
4026 | */ | |
4027 | static void set_curr_task_fair(struct rq *rq) | |
4028 | { | |
4029 | struct sched_entity *se = &rq->curr->se; | |
4030 | ||
4031 | for_each_sched_entity(se) | |
4032 | set_next_entity(cfs_rq_of(se), se); | |
4033 | } | |
4034 | ||
810b3817 | 4035 | #ifdef CONFIG_FAIR_GROUP_SCHED |
b2b5ce02 | 4036 | static void task_move_group_fair(struct task_struct *p, int on_rq) |
810b3817 | 4037 | { |
b2b5ce02 PZ |
4038 | /* |
4039 | * If the task was not on the rq at the time of this cgroup movement | |
4040 | * it must have been asleep, sleeping tasks keep their ->vruntime | |
4041 | * absolute on their old rq until wakeup (needed for the fair sleeper | |
4042 | * bonus in place_entity()). | |
4043 | * | |
4044 | * If it was on the rq, we've just 'preempted' it, which does convert | |
4045 | * ->vruntime to a relative base. | |
4046 | * | |
4047 | * Make sure both cases convert their relative position when migrating | |
4048 | * to another cgroup's rq. This does somewhat interfere with the | |
4049 | * fair sleeper stuff for the first placement, but who cares. | |
4050 | */ | |
4051 | if (!on_rq) | |
4052 | p->se.vruntime -= cfs_rq_of(&p->se)->min_vruntime; | |
4053 | set_task_rq(p, task_cpu(p)); | |
88ec22d3 | 4054 | if (!on_rq) |
b2b5ce02 | 4055 | p->se.vruntime += cfs_rq_of(&p->se)->min_vruntime; |
810b3817 PZ |
4056 | } |
4057 | #endif | |
4058 | ||
6d686f45 | 4059 | static unsigned int get_rr_interval_fair(struct rq *rq, struct task_struct *task) |
0d721cea PW |
4060 | { |
4061 | struct sched_entity *se = &task->se; | |
0d721cea PW |
4062 | unsigned int rr_interval = 0; |
4063 | ||
4064 | /* | |
4065 | * Time slice is 0 for SCHED_OTHER tasks that are on an otherwise | |
4066 | * idle runqueue: | |
4067 | */ | |
0d721cea PW |
4068 | if (rq->cfs.load.weight) |
4069 | rr_interval = NS_TO_JIFFIES(sched_slice(&rq->cfs, se)); | |
0d721cea PW |
4070 | |
4071 | return rr_interval; | |
4072 | } | |
4073 | ||
bf0f6f24 IM |
4074 | /* |
4075 | * All the scheduling class methods: | |
4076 | */ | |
5522d5d5 IM |
4077 | static const struct sched_class fair_sched_class = { |
4078 | .next = &idle_sched_class, | |
bf0f6f24 IM |
4079 | .enqueue_task = enqueue_task_fair, |
4080 | .dequeue_task = dequeue_task_fair, | |
4081 | .yield_task = yield_task_fair, | |
4082 | ||
2e09bf55 | 4083 | .check_preempt_curr = check_preempt_wakeup, |
bf0f6f24 IM |
4084 | |
4085 | .pick_next_task = pick_next_task_fair, | |
4086 | .put_prev_task = put_prev_task_fair, | |
4087 | ||
681f3e68 | 4088 | #ifdef CONFIG_SMP |
4ce72a2c LZ |
4089 | .select_task_rq = select_task_rq_fair, |
4090 | ||
0bcdcf28 CE |
4091 | .rq_online = rq_online_fair, |
4092 | .rq_offline = rq_offline_fair, | |
88ec22d3 PZ |
4093 | |
4094 | .task_waking = task_waking_fair, | |
681f3e68 | 4095 | #endif |
bf0f6f24 | 4096 | |
83b699ed | 4097 | .set_curr_task = set_curr_task_fair, |
bf0f6f24 | 4098 | .task_tick = task_tick_fair, |
cd29fe6f | 4099 | .task_fork = task_fork_fair, |
cb469845 SR |
4100 | |
4101 | .prio_changed = prio_changed_fair, | |
4102 | .switched_to = switched_to_fair, | |
810b3817 | 4103 | |
0d721cea PW |
4104 | .get_rr_interval = get_rr_interval_fair, |
4105 | ||
810b3817 | 4106 | #ifdef CONFIG_FAIR_GROUP_SCHED |
b2b5ce02 | 4107 | .task_move_group = task_move_group_fair, |
810b3817 | 4108 | #endif |
bf0f6f24 IM |
4109 | }; |
4110 | ||
4111 | #ifdef CONFIG_SCHED_DEBUG | |
5cef9eca | 4112 | static void print_cfs_stats(struct seq_file *m, int cpu) |
bf0f6f24 | 4113 | { |
bf0f6f24 IM |
4114 | struct cfs_rq *cfs_rq; |
4115 | ||
5973e5b9 | 4116 | rcu_read_lock(); |
c3b64f1e | 4117 | for_each_leaf_cfs_rq(cpu_rq(cpu), cfs_rq) |
5cef9eca | 4118 | print_cfs_rq(m, cpu, cfs_rq); |
5973e5b9 | 4119 | rcu_read_unlock(); |
bf0f6f24 IM |
4120 | } |
4121 | #endif |