Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * kernel/sched.c | |
3 | * | |
4 | * Kernel scheduler and related syscalls | |
5 | * | |
6 | * Copyright (C) 1991-2002 Linus Torvalds | |
7 | * | |
8 | * 1996-12-23 Modified by Dave Grothe to fix bugs in semaphores and | |
9 | * make semaphores SMP safe | |
10 | * 1998-11-19 Implemented schedule_timeout() and related stuff | |
11 | * by Andrea Arcangeli | |
12 | * 2002-01-04 New ultra-scalable O(1) scheduler by Ingo Molnar: | |
13 | * hybrid priority-list and round-robin design with | |
14 | * an array-switch method of distributing timeslices | |
15 | * and per-CPU runqueues. Cleanups and useful suggestions | |
16 | * by Davide Libenzi, preemptible kernel bits by Robert Love. | |
17 | * 2003-09-03 Interactivity tuning by Con Kolivas. | |
18 | * 2004-04-02 Scheduler domains code by Nick Piggin | |
19 | */ | |
20 | ||
21 | #include <linux/mm.h> | |
22 | #include <linux/module.h> | |
23 | #include <linux/nmi.h> | |
24 | #include <linux/init.h> | |
25 | #include <asm/uaccess.h> | |
26 | #include <linux/highmem.h> | |
27 | #include <linux/smp_lock.h> | |
28 | #include <asm/mmu_context.h> | |
29 | #include <linux/interrupt.h> | |
c59ede7b | 30 | #include <linux/capability.h> |
1da177e4 LT |
31 | #include <linux/completion.h> |
32 | #include <linux/kernel_stat.h> | |
9a11b49a | 33 | #include <linux/debug_locks.h> |
1da177e4 LT |
34 | #include <linux/security.h> |
35 | #include <linux/notifier.h> | |
36 | #include <linux/profile.h> | |
7dfb7103 | 37 | #include <linux/freezer.h> |
198e2f18 | 38 | #include <linux/vmalloc.h> |
1da177e4 LT |
39 | #include <linux/blkdev.h> |
40 | #include <linux/delay.h> | |
41 | #include <linux/smp.h> | |
42 | #include <linux/threads.h> | |
43 | #include <linux/timer.h> | |
44 | #include <linux/rcupdate.h> | |
45 | #include <linux/cpu.h> | |
46 | #include <linux/cpuset.h> | |
47 | #include <linux/percpu.h> | |
48 | #include <linux/kthread.h> | |
49 | #include <linux/seq_file.h> | |
50 | #include <linux/syscalls.h> | |
51 | #include <linux/times.h> | |
8f0ab514 | 52 | #include <linux/tsacct_kern.h> |
c6fd91f0 | 53 | #include <linux/kprobes.h> |
0ff92245 | 54 | #include <linux/delayacct.h> |
5517d86b | 55 | #include <linux/reciprocal_div.h> |
1da177e4 | 56 | |
5517d86b | 57 | #include <asm/tlb.h> |
1da177e4 LT |
58 | #include <asm/unistd.h> |
59 | ||
b035b6de AD |
60 | /* |
61 | * Scheduler clock - returns current time in nanosec units. | |
62 | * This is default implementation. | |
63 | * Architectures and sub-architectures can override this. | |
64 | */ | |
65 | unsigned long long __attribute__((weak)) sched_clock(void) | |
66 | { | |
67 | return (unsigned long long)jiffies * (1000000000 / HZ); | |
68 | } | |
69 | ||
1da177e4 LT |
70 | /* |
71 | * Convert user-nice values [ -20 ... 0 ... 19 ] | |
72 | * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ], | |
73 | * and back. | |
74 | */ | |
75 | #define NICE_TO_PRIO(nice) (MAX_RT_PRIO + (nice) + 20) | |
76 | #define PRIO_TO_NICE(prio) ((prio) - MAX_RT_PRIO - 20) | |
77 | #define TASK_NICE(p) PRIO_TO_NICE((p)->static_prio) | |
78 | ||
79 | /* | |
80 | * 'User priority' is the nice value converted to something we | |
81 | * can work with better when scaling various scheduler parameters, | |
82 | * it's a [ 0 ... 39 ] range. | |
83 | */ | |
84 | #define USER_PRIO(p) ((p)-MAX_RT_PRIO) | |
85 | #define TASK_USER_PRIO(p) USER_PRIO((p)->static_prio) | |
86 | #define MAX_USER_PRIO (USER_PRIO(MAX_PRIO)) | |
87 | ||
88 | /* | |
89 | * Some helpers for converting nanosecond timing to jiffy resolution | |
90 | */ | |
91 | #define NS_TO_JIFFIES(TIME) ((TIME) / (1000000000 / HZ)) | |
92 | #define JIFFIES_TO_NS(TIME) ((TIME) * (1000000000 / HZ)) | |
93 | ||
6aa645ea IM |
94 | #define NICE_0_LOAD SCHED_LOAD_SCALE |
95 | #define NICE_0_SHIFT SCHED_LOAD_SHIFT | |
96 | ||
1da177e4 LT |
97 | /* |
98 | * These are the 'tuning knobs' of the scheduler: | |
99 | * | |
100 | * Minimum timeslice is 5 msecs (or 1 jiffy, whichever is larger), | |
101 | * default timeslice is 100 msecs, maximum timeslice is 800 msecs. | |
102 | * Timeslices get refilled after they expire. | |
103 | */ | |
104 | #define MIN_TIMESLICE max(5 * HZ / 1000, 1) | |
105 | #define DEF_TIMESLICE (100 * HZ / 1000) | |
106 | #define ON_RUNQUEUE_WEIGHT 30 | |
107 | #define CHILD_PENALTY 95 | |
108 | #define PARENT_PENALTY 100 | |
109 | #define EXIT_WEIGHT 3 | |
110 | #define PRIO_BONUS_RATIO 25 | |
111 | #define MAX_BONUS (MAX_USER_PRIO * PRIO_BONUS_RATIO / 100) | |
112 | #define INTERACTIVE_DELTA 2 | |
113 | #define MAX_SLEEP_AVG (DEF_TIMESLICE * MAX_BONUS) | |
114 | #define STARVATION_LIMIT (MAX_SLEEP_AVG) | |
115 | #define NS_MAX_SLEEP_AVG (JIFFIES_TO_NS(MAX_SLEEP_AVG)) | |
116 | ||
117 | /* | |
118 | * If a task is 'interactive' then we reinsert it in the active | |
119 | * array after it has expired its current timeslice. (it will not | |
120 | * continue to run immediately, it will still roundrobin with | |
121 | * other interactive tasks.) | |
122 | * | |
123 | * This part scales the interactivity limit depending on niceness. | |
124 | * | |
125 | * We scale it linearly, offset by the INTERACTIVE_DELTA delta. | |
126 | * Here are a few examples of different nice levels: | |
127 | * | |
128 | * TASK_INTERACTIVE(-20): [1,1,1,1,1,1,1,1,1,0,0] | |
129 | * TASK_INTERACTIVE(-10): [1,1,1,1,1,1,1,0,0,0,0] | |
130 | * TASK_INTERACTIVE( 0): [1,1,1,1,0,0,0,0,0,0,0] | |
131 | * TASK_INTERACTIVE( 10): [1,1,0,0,0,0,0,0,0,0,0] | |
132 | * TASK_INTERACTIVE( 19): [0,0,0,0,0,0,0,0,0,0,0] | |
133 | * | |
134 | * (the X axis represents the possible -5 ... 0 ... +5 dynamic | |
135 | * priority range a task can explore, a value of '1' means the | |
136 | * task is rated interactive.) | |
137 | * | |
138 | * Ie. nice +19 tasks can never get 'interactive' enough to be | |
139 | * reinserted into the active array. And only heavily CPU-hog nice -20 | |
140 | * tasks will be expired. Default nice 0 tasks are somewhere between, | |
141 | * it takes some effort for them to get interactive, but it's not | |
142 | * too hard. | |
143 | */ | |
144 | ||
145 | #define CURRENT_BONUS(p) \ | |
146 | (NS_TO_JIFFIES((p)->sleep_avg) * MAX_BONUS / \ | |
147 | MAX_SLEEP_AVG) | |
148 | ||
149 | #define GRANULARITY (10 * HZ / 1000 ? : 1) | |
150 | ||
151 | #ifdef CONFIG_SMP | |
152 | #define TIMESLICE_GRANULARITY(p) (GRANULARITY * \ | |
153 | (1 << (((MAX_BONUS - CURRENT_BONUS(p)) ? : 1) - 1)) * \ | |
154 | num_online_cpus()) | |
155 | #else | |
156 | #define TIMESLICE_GRANULARITY(p) (GRANULARITY * \ | |
157 | (1 << (((MAX_BONUS - CURRENT_BONUS(p)) ? : 1) - 1))) | |
158 | #endif | |
159 | ||
160 | #define SCALE(v1,v1_max,v2_max) \ | |
161 | (v1) * (v2_max) / (v1_max) | |
162 | ||
163 | #define DELTA(p) \ | |
013d3868 MA |
164 | (SCALE(TASK_NICE(p) + 20, 40, MAX_BONUS) - 20 * MAX_BONUS / 40 + \ |
165 | INTERACTIVE_DELTA) | |
1da177e4 LT |
166 | |
167 | #define TASK_INTERACTIVE(p) \ | |
168 | ((p)->prio <= (p)->static_prio - DELTA(p)) | |
169 | ||
170 | #define INTERACTIVE_SLEEP(p) \ | |
171 | (JIFFIES_TO_NS(MAX_SLEEP_AVG * \ | |
172 | (MAX_BONUS / 2 + DELTA((p)) + 1) / MAX_BONUS - 1)) | |
173 | ||
174 | #define TASK_PREEMPTS_CURR(p, rq) \ | |
d5f9f942 | 175 | ((p)->prio < (rq)->curr->prio) |
1da177e4 | 176 | |
1da177e4 | 177 | #define SCALE_PRIO(x, prio) \ |
2dd73a4f | 178 | max(x * (MAX_PRIO - prio) / (MAX_USER_PRIO / 2), MIN_TIMESLICE) |
1da177e4 | 179 | |
2dd73a4f | 180 | static unsigned int static_prio_timeslice(int static_prio) |
1da177e4 | 181 | { |
2dd73a4f PW |
182 | if (static_prio < NICE_TO_PRIO(0)) |
183 | return SCALE_PRIO(DEF_TIMESLICE * 4, static_prio); | |
1da177e4 | 184 | else |
2dd73a4f | 185 | return SCALE_PRIO(DEF_TIMESLICE, static_prio); |
1da177e4 | 186 | } |
2dd73a4f | 187 | |
5517d86b ED |
188 | #ifdef CONFIG_SMP |
189 | /* | |
190 | * Divide a load by a sched group cpu_power : (load / sg->__cpu_power) | |
191 | * Since cpu_power is a 'constant', we can use a reciprocal divide. | |
192 | */ | |
193 | static inline u32 sg_div_cpu_power(const struct sched_group *sg, u32 load) | |
194 | { | |
195 | return reciprocal_divide(load, sg->reciprocal_cpu_power); | |
196 | } | |
197 | ||
198 | /* | |
199 | * Each time a sched group cpu_power is changed, | |
200 | * we must compute its reciprocal value | |
201 | */ | |
202 | static inline void sg_inc_cpu_power(struct sched_group *sg, u32 val) | |
203 | { | |
204 | sg->__cpu_power += val; | |
205 | sg->reciprocal_cpu_power = reciprocal_value(sg->__cpu_power); | |
206 | } | |
207 | #endif | |
208 | ||
91fcdd4e BP |
209 | /* |
210 | * task_timeslice() scales user-nice values [ -20 ... 0 ... 19 ] | |
211 | * to time slice values: [800ms ... 100ms ... 5ms] | |
212 | * | |
213 | * The higher a thread's priority, the bigger timeslices | |
214 | * it gets during one round of execution. But even the lowest | |
215 | * priority thread gets MIN_TIMESLICE worth of execution time. | |
216 | */ | |
217 | ||
36c8b586 | 218 | static inline unsigned int task_timeslice(struct task_struct *p) |
2dd73a4f PW |
219 | { |
220 | return static_prio_timeslice(p->static_prio); | |
221 | } | |
222 | ||
e05606d3 IM |
223 | static inline int rt_policy(int policy) |
224 | { | |
225 | if (unlikely(policy == SCHED_FIFO) || unlikely(policy == SCHED_RR)) | |
226 | return 1; | |
227 | return 0; | |
228 | } | |
229 | ||
230 | static inline int task_has_rt_policy(struct task_struct *p) | |
231 | { | |
232 | return rt_policy(p->policy); | |
233 | } | |
234 | ||
1da177e4 | 235 | /* |
6aa645ea | 236 | * This is the priority-queue data structure of the RT scheduling class: |
1da177e4 | 237 | */ |
6aa645ea IM |
238 | struct rt_prio_array { |
239 | DECLARE_BITMAP(bitmap, MAX_RT_PRIO+1); /* include 1 bit for delimiter */ | |
240 | struct list_head queue[MAX_RT_PRIO]; | |
241 | }; | |
242 | ||
243 | struct load_stat { | |
244 | struct load_weight load; | |
245 | u64 load_update_start, load_update_last; | |
246 | unsigned long delta_fair, delta_exec, delta_stat; | |
247 | }; | |
248 | ||
249 | /* CFS-related fields in a runqueue */ | |
250 | struct cfs_rq { | |
251 | struct load_weight load; | |
252 | unsigned long nr_running; | |
253 | ||
254 | s64 fair_clock; | |
255 | u64 exec_clock; | |
256 | s64 wait_runtime; | |
257 | u64 sleeper_bonus; | |
258 | unsigned long wait_runtime_overruns, wait_runtime_underruns; | |
259 | ||
260 | struct rb_root tasks_timeline; | |
261 | struct rb_node *rb_leftmost; | |
262 | struct rb_node *rb_load_balance_curr; | |
263 | #ifdef CONFIG_FAIR_GROUP_SCHED | |
264 | /* 'curr' points to currently running entity on this cfs_rq. | |
265 | * It is set to NULL otherwise (i.e when none are currently running). | |
266 | */ | |
267 | struct sched_entity *curr; | |
268 | struct rq *rq; /* cpu runqueue to which this cfs_rq is attached */ | |
269 | ||
270 | /* leaf cfs_rqs are those that hold tasks (lowest schedulable entity in | |
271 | * a hierarchy). Non-leaf lrqs hold other higher schedulable entities | |
272 | * (like users, containers etc.) | |
273 | * | |
274 | * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This | |
275 | * list is used during load balance. | |
276 | */ | |
277 | struct list_head leaf_cfs_rq_list; /* Better name : task_cfs_rq_list? */ | |
278 | #endif | |
279 | }; | |
1da177e4 | 280 | |
6aa645ea IM |
281 | /* Real-Time classes' related field in a runqueue: */ |
282 | struct rt_rq { | |
283 | struct rt_prio_array active; | |
284 | int rt_load_balance_idx; | |
285 | struct list_head *rt_load_balance_head, *rt_load_balance_curr; | |
286 | }; | |
287 | ||
288 | /* | |
289 | * The prio-array type of the old scheduler: | |
290 | */ | |
1da177e4 LT |
291 | struct prio_array { |
292 | unsigned int nr_active; | |
d444886e | 293 | DECLARE_BITMAP(bitmap, MAX_PRIO+1); /* include 1 bit for delimiter */ |
1da177e4 LT |
294 | struct list_head queue[MAX_PRIO]; |
295 | }; | |
296 | ||
297 | /* | |
298 | * This is the main, per-CPU runqueue data structure. | |
299 | * | |
300 | * Locking rule: those places that want to lock multiple runqueues | |
301 | * (such as the load balancing or the thread migration code), lock | |
302 | * acquire operations must be ordered by ascending &runqueue. | |
303 | */ | |
70b97a7f | 304 | struct rq { |
6aa645ea | 305 | spinlock_t lock; /* runqueue lock */ |
1da177e4 LT |
306 | |
307 | /* | |
308 | * nr_running and cpu_load should be in the same cacheline because | |
309 | * remote CPUs use both these fields when doing load calculation. | |
310 | */ | |
311 | unsigned long nr_running; | |
2dd73a4f | 312 | unsigned long raw_weighted_load; |
6aa645ea IM |
313 | #define CPU_LOAD_IDX_MAX 5 |
314 | unsigned long cpu_load[CPU_LOAD_IDX_MAX]; | |
bdecea3a | 315 | unsigned char idle_at_tick; |
46cb4b7c SS |
316 | #ifdef CONFIG_NO_HZ |
317 | unsigned char in_nohz_recently; | |
318 | #endif | |
6aa645ea IM |
319 | struct load_stat ls; /* capture load from *all* tasks on this cpu */ |
320 | unsigned long nr_load_updates; | |
321 | u64 nr_switches; | |
322 | ||
323 | struct cfs_rq cfs; | |
324 | #ifdef CONFIG_FAIR_GROUP_SCHED | |
325 | struct list_head leaf_cfs_rq_list; /* list of leaf cfs_rq on this cpu */ | |
1da177e4 | 326 | #endif |
6aa645ea | 327 | struct rt_rq rt; |
1da177e4 LT |
328 | |
329 | /* | |
330 | * This is part of a global counter where only the total sum | |
331 | * over all CPUs matters. A task can increase this counter on | |
332 | * one CPU and if it got migrated afterwards it may decrease | |
333 | * it on another CPU. Always updated under the runqueue lock: | |
334 | */ | |
335 | unsigned long nr_uninterruptible; | |
336 | ||
337 | unsigned long expired_timestamp; | |
b18ec803 | 338 | unsigned long long most_recent_timestamp; |
6aa645ea | 339 | |
36c8b586 | 340 | struct task_struct *curr, *idle; |
c9819f45 | 341 | unsigned long next_balance; |
1da177e4 | 342 | struct mm_struct *prev_mm; |
6aa645ea | 343 | |
70b97a7f | 344 | struct prio_array *active, *expired, arrays[2]; |
1da177e4 | 345 | int best_expired_prio; |
6aa645ea IM |
346 | |
347 | u64 clock, prev_clock_raw; | |
348 | s64 clock_max_delta; | |
349 | ||
350 | unsigned int clock_warps, clock_overflows; | |
351 | unsigned int clock_unstable_events; | |
352 | ||
353 | struct sched_class *load_balance_class; | |
354 | ||
1da177e4 LT |
355 | atomic_t nr_iowait; |
356 | ||
357 | #ifdef CONFIG_SMP | |
358 | struct sched_domain *sd; | |
359 | ||
360 | /* For active balancing */ | |
361 | int active_balance; | |
362 | int push_cpu; | |
0a2966b4 | 363 | int cpu; /* cpu of this runqueue */ |
1da177e4 | 364 | |
36c8b586 | 365 | struct task_struct *migration_thread; |
1da177e4 LT |
366 | struct list_head migration_queue; |
367 | #endif | |
368 | ||
369 | #ifdef CONFIG_SCHEDSTATS | |
370 | /* latency stats */ | |
371 | struct sched_info rq_sched_info; | |
372 | ||
373 | /* sys_sched_yield() stats */ | |
374 | unsigned long yld_exp_empty; | |
375 | unsigned long yld_act_empty; | |
376 | unsigned long yld_both_empty; | |
377 | unsigned long yld_cnt; | |
378 | ||
379 | /* schedule() stats */ | |
380 | unsigned long sched_switch; | |
381 | unsigned long sched_cnt; | |
382 | unsigned long sched_goidle; | |
383 | ||
384 | /* try_to_wake_up() stats */ | |
385 | unsigned long ttwu_cnt; | |
386 | unsigned long ttwu_local; | |
387 | #endif | |
fcb99371 | 388 | struct lock_class_key rq_lock_key; |
1da177e4 LT |
389 | }; |
390 | ||
c3396620 | 391 | static DEFINE_PER_CPU(struct rq, runqueues) ____cacheline_aligned_in_smp; |
5be9361c | 392 | static DEFINE_MUTEX(sched_hotcpu_mutex); |
1da177e4 | 393 | |
dd41f596 IM |
394 | static inline void check_preempt_curr(struct rq *rq, struct task_struct *p) |
395 | { | |
396 | rq->curr->sched_class->check_preempt_curr(rq, p); | |
397 | } | |
398 | ||
0a2966b4 CL |
399 | static inline int cpu_of(struct rq *rq) |
400 | { | |
401 | #ifdef CONFIG_SMP | |
402 | return rq->cpu; | |
403 | #else | |
404 | return 0; | |
405 | #endif | |
406 | } | |
407 | ||
20d315d4 IM |
408 | /* |
409 | * Per-runqueue clock, as finegrained as the platform can give us: | |
410 | */ | |
411 | static unsigned long long __rq_clock(struct rq *rq) | |
412 | { | |
413 | u64 prev_raw = rq->prev_clock_raw; | |
414 | u64 now = sched_clock(); | |
415 | s64 delta = now - prev_raw; | |
416 | u64 clock = rq->clock; | |
417 | ||
418 | /* | |
419 | * Protect against sched_clock() occasionally going backwards: | |
420 | */ | |
421 | if (unlikely(delta < 0)) { | |
422 | clock++; | |
423 | rq->clock_warps++; | |
424 | } else { | |
425 | /* | |
426 | * Catch too large forward jumps too: | |
427 | */ | |
428 | if (unlikely(delta > 2*TICK_NSEC)) { | |
429 | clock++; | |
430 | rq->clock_overflows++; | |
431 | } else { | |
432 | if (unlikely(delta > rq->clock_max_delta)) | |
433 | rq->clock_max_delta = delta; | |
434 | clock += delta; | |
435 | } | |
436 | } | |
437 | ||
438 | rq->prev_clock_raw = now; | |
439 | rq->clock = clock; | |
440 | ||
441 | return clock; | |
442 | } | |
443 | ||
444 | static inline unsigned long long rq_clock(struct rq *rq) | |
445 | { | |
446 | int this_cpu = smp_processor_id(); | |
447 | ||
448 | if (this_cpu == cpu_of(rq)) | |
449 | return __rq_clock(rq); | |
450 | ||
451 | return rq->clock; | |
452 | } | |
453 | ||
674311d5 NP |
454 | /* |
455 | * The domain tree (rq->sd) is protected by RCU's quiescent state transition. | |
1a20ff27 | 456 | * See detach_destroy_domains: synchronize_sched for details. |
674311d5 NP |
457 | * |
458 | * The domain tree of any CPU may only be accessed from within | |
459 | * preempt-disabled sections. | |
460 | */ | |
48f24c4d IM |
461 | #define for_each_domain(cpu, __sd) \ |
462 | for (__sd = rcu_dereference(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent) | |
1da177e4 LT |
463 | |
464 | #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu))) | |
465 | #define this_rq() (&__get_cpu_var(runqueues)) | |
466 | #define task_rq(p) cpu_rq(task_cpu(p)) | |
467 | #define cpu_curr(cpu) (cpu_rq(cpu)->curr) | |
468 | ||
138a8aeb IM |
469 | #ifdef CONFIG_FAIR_GROUP_SCHED |
470 | /* Change a task's ->cfs_rq if it moves across CPUs */ | |
471 | static inline void set_task_cfs_rq(struct task_struct *p) | |
472 | { | |
473 | p->se.cfs_rq = &task_rq(p)->cfs; | |
474 | } | |
475 | #else | |
476 | static inline void set_task_cfs_rq(struct task_struct *p) | |
477 | { | |
478 | } | |
479 | #endif | |
480 | ||
1da177e4 | 481 | #ifndef prepare_arch_switch |
4866cde0 NP |
482 | # define prepare_arch_switch(next) do { } while (0) |
483 | #endif | |
484 | #ifndef finish_arch_switch | |
485 | # define finish_arch_switch(prev) do { } while (0) | |
486 | #endif | |
487 | ||
488 | #ifndef __ARCH_WANT_UNLOCKED_CTXSW | |
70b97a7f | 489 | static inline int task_running(struct rq *rq, struct task_struct *p) |
4866cde0 NP |
490 | { |
491 | return rq->curr == p; | |
492 | } | |
493 | ||
70b97a7f | 494 | static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next) |
4866cde0 NP |
495 | { |
496 | } | |
497 | ||
70b97a7f | 498 | static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev) |
4866cde0 | 499 | { |
da04c035 IM |
500 | #ifdef CONFIG_DEBUG_SPINLOCK |
501 | /* this is a valid case when another task releases the spinlock */ | |
502 | rq->lock.owner = current; | |
503 | #endif | |
8a25d5de IM |
504 | /* |
505 | * If we are tracking spinlock dependencies then we have to | |
506 | * fix up the runqueue lock - which gets 'carried over' from | |
507 | * prev into current: | |
508 | */ | |
509 | spin_acquire(&rq->lock.dep_map, 0, 0, _THIS_IP_); | |
510 | ||
4866cde0 NP |
511 | spin_unlock_irq(&rq->lock); |
512 | } | |
513 | ||
514 | #else /* __ARCH_WANT_UNLOCKED_CTXSW */ | |
70b97a7f | 515 | static inline int task_running(struct rq *rq, struct task_struct *p) |
4866cde0 NP |
516 | { |
517 | #ifdef CONFIG_SMP | |
518 | return p->oncpu; | |
519 | #else | |
520 | return rq->curr == p; | |
521 | #endif | |
522 | } | |
523 | ||
70b97a7f | 524 | static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next) |
4866cde0 NP |
525 | { |
526 | #ifdef CONFIG_SMP | |
527 | /* | |
528 | * We can optimise this out completely for !SMP, because the | |
529 | * SMP rebalancing from interrupt is the only thing that cares | |
530 | * here. | |
531 | */ | |
532 | next->oncpu = 1; | |
533 | #endif | |
534 | #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW | |
535 | spin_unlock_irq(&rq->lock); | |
536 | #else | |
537 | spin_unlock(&rq->lock); | |
538 | #endif | |
539 | } | |
540 | ||
70b97a7f | 541 | static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev) |
4866cde0 NP |
542 | { |
543 | #ifdef CONFIG_SMP | |
544 | /* | |
545 | * After ->oncpu is cleared, the task can be moved to a different CPU. | |
546 | * We must ensure this doesn't happen until the switch is completely | |
547 | * finished. | |
548 | */ | |
549 | smp_wmb(); | |
550 | prev->oncpu = 0; | |
551 | #endif | |
552 | #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW | |
553 | local_irq_enable(); | |
1da177e4 | 554 | #endif |
4866cde0 NP |
555 | } |
556 | #endif /* __ARCH_WANT_UNLOCKED_CTXSW */ | |
1da177e4 | 557 | |
b29739f9 IM |
558 | /* |
559 | * __task_rq_lock - lock the runqueue a given task resides on. | |
560 | * Must be called interrupts disabled. | |
561 | */ | |
70b97a7f | 562 | static inline struct rq *__task_rq_lock(struct task_struct *p) |
b29739f9 IM |
563 | __acquires(rq->lock) |
564 | { | |
70b97a7f | 565 | struct rq *rq; |
b29739f9 IM |
566 | |
567 | repeat_lock_task: | |
568 | rq = task_rq(p); | |
569 | spin_lock(&rq->lock); | |
570 | if (unlikely(rq != task_rq(p))) { | |
571 | spin_unlock(&rq->lock); | |
572 | goto repeat_lock_task; | |
573 | } | |
574 | return rq; | |
575 | } | |
576 | ||
1da177e4 LT |
577 | /* |
578 | * task_rq_lock - lock the runqueue a given task resides on and disable | |
579 | * interrupts. Note the ordering: we can safely lookup the task_rq without | |
580 | * explicitly disabling preemption. | |
581 | */ | |
70b97a7f | 582 | static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags) |
1da177e4 LT |
583 | __acquires(rq->lock) |
584 | { | |
70b97a7f | 585 | struct rq *rq; |
1da177e4 LT |
586 | |
587 | repeat_lock_task: | |
588 | local_irq_save(*flags); | |
589 | rq = task_rq(p); | |
590 | spin_lock(&rq->lock); | |
591 | if (unlikely(rq != task_rq(p))) { | |
592 | spin_unlock_irqrestore(&rq->lock, *flags); | |
593 | goto repeat_lock_task; | |
594 | } | |
595 | return rq; | |
596 | } | |
597 | ||
70b97a7f | 598 | static inline void __task_rq_unlock(struct rq *rq) |
b29739f9 IM |
599 | __releases(rq->lock) |
600 | { | |
601 | spin_unlock(&rq->lock); | |
602 | } | |
603 | ||
70b97a7f | 604 | static inline void task_rq_unlock(struct rq *rq, unsigned long *flags) |
1da177e4 LT |
605 | __releases(rq->lock) |
606 | { | |
607 | spin_unlock_irqrestore(&rq->lock, *flags); | |
608 | } | |
609 | ||
1da177e4 | 610 | /* |
cc2a73b5 | 611 | * this_rq_lock - lock this runqueue and disable interrupts. |
1da177e4 | 612 | */ |
70b97a7f | 613 | static inline struct rq *this_rq_lock(void) |
1da177e4 LT |
614 | __acquires(rq->lock) |
615 | { | |
70b97a7f | 616 | struct rq *rq; |
1da177e4 LT |
617 | |
618 | local_irq_disable(); | |
619 | rq = this_rq(); | |
620 | spin_lock(&rq->lock); | |
621 | ||
622 | return rq; | |
623 | } | |
624 | ||
c24d20db IM |
625 | /* |
626 | * resched_task - mark a task 'to be rescheduled now'. | |
627 | * | |
628 | * On UP this means the setting of the need_resched flag, on SMP it | |
629 | * might also involve a cross-CPU call to trigger the scheduler on | |
630 | * the target CPU. | |
631 | */ | |
632 | #ifdef CONFIG_SMP | |
633 | ||
634 | #ifndef tsk_is_polling | |
635 | #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG) | |
636 | #endif | |
637 | ||
638 | static void resched_task(struct task_struct *p) | |
639 | { | |
640 | int cpu; | |
641 | ||
642 | assert_spin_locked(&task_rq(p)->lock); | |
643 | ||
644 | if (unlikely(test_tsk_thread_flag(p, TIF_NEED_RESCHED))) | |
645 | return; | |
646 | ||
647 | set_tsk_thread_flag(p, TIF_NEED_RESCHED); | |
648 | ||
649 | cpu = task_cpu(p); | |
650 | if (cpu == smp_processor_id()) | |
651 | return; | |
652 | ||
653 | /* NEED_RESCHED must be visible before we test polling */ | |
654 | smp_mb(); | |
655 | if (!tsk_is_polling(p)) | |
656 | smp_send_reschedule(cpu); | |
657 | } | |
658 | ||
659 | static void resched_cpu(int cpu) | |
660 | { | |
661 | struct rq *rq = cpu_rq(cpu); | |
662 | unsigned long flags; | |
663 | ||
664 | if (!spin_trylock_irqsave(&rq->lock, flags)) | |
665 | return; | |
666 | resched_task(cpu_curr(cpu)); | |
667 | spin_unlock_irqrestore(&rq->lock, flags); | |
668 | } | |
669 | #else | |
670 | static inline void resched_task(struct task_struct *p) | |
671 | { | |
672 | assert_spin_locked(&task_rq(p)->lock); | |
673 | set_tsk_need_resched(p); | |
674 | } | |
675 | #endif | |
676 | ||
45bf76df IM |
677 | static u64 div64_likely32(u64 divident, unsigned long divisor) |
678 | { | |
679 | #if BITS_PER_LONG == 32 | |
680 | if (likely(divident <= 0xffffffffULL)) | |
681 | return (u32)divident / divisor; | |
682 | do_div(divident, divisor); | |
683 | ||
684 | return divident; | |
685 | #else | |
686 | return divident / divisor; | |
687 | #endif | |
688 | } | |
689 | ||
690 | #if BITS_PER_LONG == 32 | |
691 | # define WMULT_CONST (~0UL) | |
692 | #else | |
693 | # define WMULT_CONST (1UL << 32) | |
694 | #endif | |
695 | ||
696 | #define WMULT_SHIFT 32 | |
697 | ||
698 | static inline unsigned long | |
699 | calc_delta_mine(unsigned long delta_exec, unsigned long weight, | |
700 | struct load_weight *lw) | |
701 | { | |
702 | u64 tmp; | |
703 | ||
704 | if (unlikely(!lw->inv_weight)) | |
705 | lw->inv_weight = WMULT_CONST / lw->weight; | |
706 | ||
707 | tmp = (u64)delta_exec * weight; | |
708 | /* | |
709 | * Check whether we'd overflow the 64-bit multiplication: | |
710 | */ | |
711 | if (unlikely(tmp > WMULT_CONST)) { | |
712 | tmp = ((tmp >> WMULT_SHIFT/2) * lw->inv_weight) | |
713 | >> (WMULT_SHIFT/2); | |
714 | } else { | |
715 | tmp = (tmp * lw->inv_weight) >> WMULT_SHIFT; | |
716 | } | |
717 | ||
718 | return (unsigned long)min(tmp, (u64)sysctl_sched_runtime_limit); | |
719 | } | |
720 | ||
721 | static inline unsigned long | |
722 | calc_delta_fair(unsigned long delta_exec, struct load_weight *lw) | |
723 | { | |
724 | return calc_delta_mine(delta_exec, NICE_0_LOAD, lw); | |
725 | } | |
726 | ||
727 | static void update_load_add(struct load_weight *lw, unsigned long inc) | |
728 | { | |
729 | lw->weight += inc; | |
730 | lw->inv_weight = 0; | |
731 | } | |
732 | ||
733 | static void update_load_sub(struct load_weight *lw, unsigned long dec) | |
734 | { | |
735 | lw->weight -= dec; | |
736 | lw->inv_weight = 0; | |
737 | } | |
738 | ||
739 | static void __update_curr_load(struct rq *rq, struct load_stat *ls) | |
740 | { | |
741 | if (rq->curr != rq->idle && ls->load.weight) { | |
742 | ls->delta_exec += ls->delta_stat; | |
743 | ls->delta_fair += calc_delta_fair(ls->delta_stat, &ls->load); | |
744 | ls->delta_stat = 0; | |
745 | } | |
746 | } | |
747 | ||
748 | /* | |
749 | * Update delta_exec, delta_fair fields for rq. | |
750 | * | |
751 | * delta_fair clock advances at a rate inversely proportional to | |
752 | * total load (rq->ls.load.weight) on the runqueue, while | |
753 | * delta_exec advances at the same rate as wall-clock (provided | |
754 | * cpu is not idle). | |
755 | * | |
756 | * delta_exec / delta_fair is a measure of the (smoothened) load on this | |
757 | * runqueue over any given interval. This (smoothened) load is used | |
758 | * during load balance. | |
759 | * | |
760 | * This function is called /before/ updating rq->ls.load | |
761 | * and when switching tasks. | |
762 | */ | |
763 | static void update_curr_load(struct rq *rq, u64 now) | |
764 | { | |
765 | struct load_stat *ls = &rq->ls; | |
766 | u64 start; | |
767 | ||
768 | start = ls->load_update_start; | |
769 | ls->load_update_start = now; | |
770 | ls->delta_stat += now - start; | |
771 | /* | |
772 | * Stagger updates to ls->delta_fair. Very frequent updates | |
773 | * can be expensive. | |
774 | */ | |
775 | if (ls->delta_stat >= sysctl_sched_stat_granularity) | |
776 | __update_curr_load(rq, ls); | |
777 | } | |
778 | ||
2dd73a4f PW |
779 | /* |
780 | * To aid in avoiding the subversion of "niceness" due to uneven distribution | |
781 | * of tasks with abnormal "nice" values across CPUs the contribution that | |
782 | * each task makes to its run queue's load is weighted according to its | |
783 | * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a | |
784 | * scaled version of the new time slice allocation that they receive on time | |
785 | * slice expiry etc. | |
786 | */ | |
787 | ||
788 | /* | |
789 | * Assume: static_prio_timeslice(NICE_TO_PRIO(0)) == DEF_TIMESLICE | |
790 | * If static_prio_timeslice() is ever changed to break this assumption then | |
791 | * this code will need modification | |
792 | */ | |
793 | #define TIME_SLICE_NICE_ZERO DEF_TIMESLICE | |
dd41f596 | 794 | #define load_weight(lp) \ |
2dd73a4f PW |
795 | (((lp) * SCHED_LOAD_SCALE) / TIME_SLICE_NICE_ZERO) |
796 | #define PRIO_TO_LOAD_WEIGHT(prio) \ | |
dd41f596 | 797 | load_weight(static_prio_timeslice(prio)) |
2dd73a4f | 798 | #define RTPRIO_TO_LOAD_WEIGHT(rp) \ |
dd41f596 IM |
799 | (PRIO_TO_LOAD_WEIGHT(MAX_RT_PRIO) + load_weight(rp)) |
800 | ||
801 | #define WEIGHT_IDLEPRIO 2 | |
802 | #define WMULT_IDLEPRIO (1 << 31) | |
803 | ||
804 | /* | |
805 | * Nice levels are multiplicative, with a gentle 10% change for every | |
806 | * nice level changed. I.e. when a CPU-bound task goes from nice 0 to | |
807 | * nice 1, it will get ~10% less CPU time than another CPU-bound task | |
808 | * that remained on nice 0. | |
809 | * | |
810 | * The "10% effect" is relative and cumulative: from _any_ nice level, | |
811 | * if you go up 1 level, it's -10% CPU usage, if you go down 1 level | |
812 | * it's +10% CPU usage. | |
813 | */ | |
814 | static const int prio_to_weight[40] = { | |
815 | /* -20 */ 88818, 71054, 56843, 45475, 36380, 29104, 23283, 18626, 14901, 11921, | |
816 | /* -10 */ 9537, 7629, 6103, 4883, 3906, 3125, 2500, 2000, 1600, 1280, | |
817 | /* 0 */ NICE_0_LOAD /* 1024 */, | |
818 | /* 1 */ 819, 655, 524, 419, 336, 268, 215, 172, 137, | |
819 | /* 10 */ 110, 87, 70, 56, 45, 36, 29, 23, 18, 15, | |
820 | }; | |
821 | ||
822 | static const u32 prio_to_wmult[40] = { | |
823 | 48356, 60446, 75558, 94446, 118058, 147573, | |
824 | 184467, 230589, 288233, 360285, 450347, | |
825 | 562979, 703746, 879575, 1099582, 1374389, | |
826 | 717986, 2147483, 2684354, 3355443, 4194304, | |
827 | 244160, 6557201, 8196502, 10250518, 12782640, | |
828 | 16025997, 19976592, 24970740, 31350126, 39045157, | |
829 | 49367440, 61356675, 76695844, 95443717, 119304647, | |
830 | 148102320, 186737708, 238609294, 286331153, | |
831 | }; | |
2dd73a4f | 832 | |
36c8b586 | 833 | static inline void |
dd41f596 | 834 | inc_load(struct rq *rq, const struct task_struct *p, u64 now) |
2dd73a4f | 835 | { |
dd41f596 IM |
836 | update_curr_load(rq, now); |
837 | update_load_add(&rq->ls.load, p->se.load.weight); | |
2dd73a4f PW |
838 | } |
839 | ||
36c8b586 | 840 | static inline void |
dd41f596 | 841 | dec_load(struct rq *rq, const struct task_struct *p, u64 now) |
2dd73a4f | 842 | { |
dd41f596 IM |
843 | update_curr_load(rq, now); |
844 | update_load_sub(&rq->ls.load, p->se.load.weight); | |
2dd73a4f PW |
845 | } |
846 | ||
dd41f596 | 847 | static inline void inc_nr_running(struct task_struct *p, struct rq *rq, u64 now) |
2dd73a4f PW |
848 | { |
849 | rq->nr_running++; | |
dd41f596 | 850 | inc_load(rq, p, now); |
2dd73a4f PW |
851 | } |
852 | ||
dd41f596 | 853 | static inline void dec_nr_running(struct task_struct *p, struct rq *rq, u64 now) |
2dd73a4f PW |
854 | { |
855 | rq->nr_running--; | |
dd41f596 | 856 | dec_load(rq, p, now); |
2dd73a4f PW |
857 | } |
858 | ||
dd41f596 IM |
859 | static void activate_task(struct rq *rq, struct task_struct *p, int wakeup); |
860 | ||
861 | /* | |
862 | * runqueue iterator, to support SMP load-balancing between different | |
863 | * scheduling classes, without having to expose their internal data | |
864 | * structures to the load-balancing proper: | |
865 | */ | |
866 | struct rq_iterator { | |
867 | void *arg; | |
868 | struct task_struct *(*start)(void *); | |
869 | struct task_struct *(*next)(void *); | |
870 | }; | |
871 | ||
872 | static int balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
873 | unsigned long max_nr_move, unsigned long max_load_move, | |
874 | struct sched_domain *sd, enum cpu_idle_type idle, | |
875 | int *all_pinned, unsigned long *load_moved, | |
876 | int this_best_prio, int best_prio, int best_prio_seen, | |
877 | struct rq_iterator *iterator); | |
878 | ||
879 | #include "sched_stats.h" | |
880 | #include "sched_rt.c" | |
881 | #include "sched_fair.c" | |
882 | #include "sched_idletask.c" | |
883 | #ifdef CONFIG_SCHED_DEBUG | |
884 | # include "sched_debug.c" | |
885 | #endif | |
886 | ||
887 | #define sched_class_highest (&rt_sched_class) | |
888 | ||
45bf76df IM |
889 | static void set_load_weight(struct task_struct *p) |
890 | { | |
dd41f596 IM |
891 | task_rq(p)->cfs.wait_runtime -= p->se.wait_runtime; |
892 | p->se.wait_runtime = 0; | |
893 | ||
45bf76df | 894 | if (task_has_rt_policy(p)) { |
dd41f596 IM |
895 | p->se.load.weight = prio_to_weight[0] * 2; |
896 | p->se.load.inv_weight = prio_to_wmult[0] >> 1; | |
897 | return; | |
898 | } | |
45bf76df | 899 | |
dd41f596 IM |
900 | /* |
901 | * SCHED_IDLE tasks get minimal weight: | |
902 | */ | |
903 | if (p->policy == SCHED_IDLE) { | |
904 | p->se.load.weight = WEIGHT_IDLEPRIO; | |
905 | p->se.load.inv_weight = WMULT_IDLEPRIO; | |
906 | return; | |
907 | } | |
71f8bd46 | 908 | |
dd41f596 IM |
909 | p->se.load.weight = prio_to_weight[p->static_prio - MAX_RT_PRIO]; |
910 | p->se.load.inv_weight = prio_to_wmult[p->static_prio - MAX_RT_PRIO]; | |
71f8bd46 IM |
911 | } |
912 | ||
dd41f596 IM |
913 | static void |
914 | enqueue_task(struct rq *rq, struct task_struct *p, int wakeup, u64 now) | |
71f8bd46 | 915 | { |
dd41f596 IM |
916 | sched_info_queued(p); |
917 | p->sched_class->enqueue_task(rq, p, wakeup, now); | |
918 | p->se.on_rq = 1; | |
71f8bd46 IM |
919 | } |
920 | ||
dd41f596 IM |
921 | static void |
922 | dequeue_task(struct rq *rq, struct task_struct *p, int sleep, u64 now) | |
71f8bd46 | 923 | { |
dd41f596 IM |
924 | p->sched_class->dequeue_task(rq, p, sleep, now); |
925 | p->se.on_rq = 0; | |
71f8bd46 IM |
926 | } |
927 | ||
14531189 | 928 | /* |
dd41f596 | 929 | * __normal_prio - return the priority that is based on the static prio |
14531189 | 930 | */ |
14531189 IM |
931 | static inline int __normal_prio(struct task_struct *p) |
932 | { | |
dd41f596 | 933 | return p->static_prio; |
14531189 IM |
934 | } |
935 | ||
b29739f9 IM |
936 | /* |
937 | * Calculate the expected normal priority: i.e. priority | |
938 | * without taking RT-inheritance into account. Might be | |
939 | * boosted by interactivity modifiers. Changes upon fork, | |
940 | * setprio syscalls, and whenever the interactivity | |
941 | * estimator recalculates. | |
942 | */ | |
36c8b586 | 943 | static inline int normal_prio(struct task_struct *p) |
b29739f9 IM |
944 | { |
945 | int prio; | |
946 | ||
e05606d3 | 947 | if (task_has_rt_policy(p)) |
b29739f9 IM |
948 | prio = MAX_RT_PRIO-1 - p->rt_priority; |
949 | else | |
950 | prio = __normal_prio(p); | |
951 | return prio; | |
952 | } | |
953 | ||
954 | /* | |
955 | * Calculate the current priority, i.e. the priority | |
956 | * taken into account by the scheduler. This value might | |
957 | * be boosted by RT tasks, or might be boosted by | |
958 | * interactivity modifiers. Will be RT if the task got | |
959 | * RT-boosted. If not then it returns p->normal_prio. | |
960 | */ | |
36c8b586 | 961 | static int effective_prio(struct task_struct *p) |
b29739f9 IM |
962 | { |
963 | p->normal_prio = normal_prio(p); | |
964 | /* | |
965 | * If we are RT tasks or we were boosted to RT priority, | |
966 | * keep the priority unchanged. Otherwise, update priority | |
967 | * to the normal priority: | |
968 | */ | |
969 | if (!rt_prio(p->prio)) | |
970 | return p->normal_prio; | |
971 | return p->prio; | |
972 | } | |
973 | ||
1da177e4 | 974 | /* |
dd41f596 | 975 | * activate_task - move a task to the runqueue. |
1da177e4 | 976 | */ |
dd41f596 | 977 | static void activate_task(struct rq *rq, struct task_struct *p, int wakeup) |
1da177e4 | 978 | { |
dd41f596 | 979 | u64 now = rq_clock(rq); |
d425b274 | 980 | |
dd41f596 IM |
981 | if (p->state == TASK_UNINTERRUPTIBLE) |
982 | rq->nr_uninterruptible--; | |
1da177e4 | 983 | |
dd41f596 IM |
984 | enqueue_task(rq, p, wakeup, now); |
985 | inc_nr_running(p, rq, now); | |
1da177e4 LT |
986 | } |
987 | ||
988 | /* | |
dd41f596 | 989 | * activate_idle_task - move idle task to the _front_ of runqueue. |
1da177e4 | 990 | */ |
dd41f596 | 991 | static inline void activate_idle_task(struct task_struct *p, struct rq *rq) |
1da177e4 | 992 | { |
dd41f596 | 993 | u64 now = rq_clock(rq); |
1da177e4 | 994 | |
dd41f596 IM |
995 | if (p->state == TASK_UNINTERRUPTIBLE) |
996 | rq->nr_uninterruptible--; | |
ece8a684 | 997 | |
dd41f596 IM |
998 | enqueue_task(rq, p, 0, now); |
999 | inc_nr_running(p, rq, now); | |
1da177e4 LT |
1000 | } |
1001 | ||
1002 | /* | |
1003 | * deactivate_task - remove a task from the runqueue. | |
1004 | */ | |
dd41f596 | 1005 | static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep) |
1da177e4 | 1006 | { |
dd41f596 IM |
1007 | u64 now = rq_clock(rq); |
1008 | ||
1009 | if (p->state == TASK_UNINTERRUPTIBLE) | |
1010 | rq->nr_uninterruptible++; | |
1011 | ||
1012 | dequeue_task(rq, p, sleep, now); | |
1013 | dec_nr_running(p, rq, now); | |
1da177e4 LT |
1014 | } |
1015 | ||
1da177e4 LT |
1016 | /** |
1017 | * task_curr - is this task currently executing on a CPU? | |
1018 | * @p: the task in question. | |
1019 | */ | |
36c8b586 | 1020 | inline int task_curr(const struct task_struct *p) |
1da177e4 LT |
1021 | { |
1022 | return cpu_curr(task_cpu(p)) == p; | |
1023 | } | |
1024 | ||
2dd73a4f PW |
1025 | /* Used instead of source_load when we know the type == 0 */ |
1026 | unsigned long weighted_cpuload(const int cpu) | |
1027 | { | |
dd41f596 IM |
1028 | return cpu_rq(cpu)->ls.load.weight; |
1029 | } | |
1030 | ||
1031 | static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu) | |
1032 | { | |
1033 | #ifdef CONFIG_SMP | |
1034 | task_thread_info(p)->cpu = cpu; | |
1035 | set_task_cfs_rq(p); | |
1036 | #endif | |
2dd73a4f PW |
1037 | } |
1038 | ||
1da177e4 | 1039 | #ifdef CONFIG_SMP |
c65cc870 | 1040 | |
dd41f596 | 1041 | void set_task_cpu(struct task_struct *p, unsigned int new_cpu) |
c65cc870 | 1042 | { |
dd41f596 IM |
1043 | int old_cpu = task_cpu(p); |
1044 | struct rq *old_rq = cpu_rq(old_cpu), *new_rq = cpu_rq(new_cpu); | |
1045 | u64 clock_offset, fair_clock_offset; | |
1046 | ||
1047 | clock_offset = old_rq->clock - new_rq->clock; | |
1048 | fair_clock_offset = old_rq->cfs.fair_clock - | |
1049 | new_rq->cfs.fair_clock; | |
1050 | if (p->se.wait_start) | |
1051 | p->se.wait_start -= clock_offset; | |
1052 | if (p->se.wait_start_fair) | |
1053 | p->se.wait_start_fair -= fair_clock_offset; | |
1054 | if (p->se.sleep_start) | |
1055 | p->se.sleep_start -= clock_offset; | |
1056 | if (p->se.block_start) | |
1057 | p->se.block_start -= clock_offset; | |
1058 | if (p->se.sleep_start_fair) | |
1059 | p->se.sleep_start_fair -= fair_clock_offset; | |
1060 | ||
1061 | __set_task_cpu(p, new_cpu); | |
c65cc870 IM |
1062 | } |
1063 | ||
70b97a7f | 1064 | struct migration_req { |
1da177e4 | 1065 | struct list_head list; |
1da177e4 | 1066 | |
36c8b586 | 1067 | struct task_struct *task; |
1da177e4 LT |
1068 | int dest_cpu; |
1069 | ||
1da177e4 | 1070 | struct completion done; |
70b97a7f | 1071 | }; |
1da177e4 LT |
1072 | |
1073 | /* | |
1074 | * The task's runqueue lock must be held. | |
1075 | * Returns true if you have to wait for migration thread. | |
1076 | */ | |
36c8b586 | 1077 | static int |
70b97a7f | 1078 | migrate_task(struct task_struct *p, int dest_cpu, struct migration_req *req) |
1da177e4 | 1079 | { |
70b97a7f | 1080 | struct rq *rq = task_rq(p); |
1da177e4 LT |
1081 | |
1082 | /* | |
1083 | * If the task is not on a runqueue (and not running), then | |
1084 | * it is sufficient to simply update the task's cpu field. | |
1085 | */ | |
dd41f596 | 1086 | if (!p->se.on_rq && !task_running(rq, p)) { |
1da177e4 LT |
1087 | set_task_cpu(p, dest_cpu); |
1088 | return 0; | |
1089 | } | |
1090 | ||
1091 | init_completion(&req->done); | |
1da177e4 LT |
1092 | req->task = p; |
1093 | req->dest_cpu = dest_cpu; | |
1094 | list_add(&req->list, &rq->migration_queue); | |
48f24c4d | 1095 | |
1da177e4 LT |
1096 | return 1; |
1097 | } | |
1098 | ||
1099 | /* | |
1100 | * wait_task_inactive - wait for a thread to unschedule. | |
1101 | * | |
1102 | * The caller must ensure that the task *will* unschedule sometime soon, | |
1103 | * else this function might spin for a *long* time. This function can't | |
1104 | * be called with interrupts off, or it may introduce deadlock with | |
1105 | * smp_call_function() if an IPI is sent by the same process we are | |
1106 | * waiting to become inactive. | |
1107 | */ | |
36c8b586 | 1108 | void wait_task_inactive(struct task_struct *p) |
1da177e4 LT |
1109 | { |
1110 | unsigned long flags; | |
dd41f596 | 1111 | int running, on_rq; |
70b97a7f | 1112 | struct rq *rq; |
1da177e4 LT |
1113 | |
1114 | repeat: | |
fa490cfd LT |
1115 | /* |
1116 | * We do the initial early heuristics without holding | |
1117 | * any task-queue locks at all. We'll only try to get | |
1118 | * the runqueue lock when things look like they will | |
1119 | * work out! | |
1120 | */ | |
1121 | rq = task_rq(p); | |
1122 | ||
1123 | /* | |
1124 | * If the task is actively running on another CPU | |
1125 | * still, just relax and busy-wait without holding | |
1126 | * any locks. | |
1127 | * | |
1128 | * NOTE! Since we don't hold any locks, it's not | |
1129 | * even sure that "rq" stays as the right runqueue! | |
1130 | * But we don't care, since "task_running()" will | |
1131 | * return false if the runqueue has changed and p | |
1132 | * is actually now running somewhere else! | |
1133 | */ | |
1134 | while (task_running(rq, p)) | |
1135 | cpu_relax(); | |
1136 | ||
1137 | /* | |
1138 | * Ok, time to look more closely! We need the rq | |
1139 | * lock now, to be *sure*. If we're wrong, we'll | |
1140 | * just go back and repeat. | |
1141 | */ | |
1da177e4 | 1142 | rq = task_rq_lock(p, &flags); |
fa490cfd | 1143 | running = task_running(rq, p); |
dd41f596 | 1144 | on_rq = p->se.on_rq; |
fa490cfd LT |
1145 | task_rq_unlock(rq, &flags); |
1146 | ||
1147 | /* | |
1148 | * Was it really running after all now that we | |
1149 | * checked with the proper locks actually held? | |
1150 | * | |
1151 | * Oops. Go back and try again.. | |
1152 | */ | |
1153 | if (unlikely(running)) { | |
1da177e4 | 1154 | cpu_relax(); |
1da177e4 LT |
1155 | goto repeat; |
1156 | } | |
fa490cfd LT |
1157 | |
1158 | /* | |
1159 | * It's not enough that it's not actively running, | |
1160 | * it must be off the runqueue _entirely_, and not | |
1161 | * preempted! | |
1162 | * | |
1163 | * So if it wa still runnable (but just not actively | |
1164 | * running right now), it's preempted, and we should | |
1165 | * yield - it could be a while. | |
1166 | */ | |
dd41f596 | 1167 | if (unlikely(on_rq)) { |
fa490cfd LT |
1168 | yield(); |
1169 | goto repeat; | |
1170 | } | |
1171 | ||
1172 | /* | |
1173 | * Ahh, all good. It wasn't running, and it wasn't | |
1174 | * runnable, which means that it will never become | |
1175 | * running in the future either. We're all done! | |
1176 | */ | |
1da177e4 LT |
1177 | } |
1178 | ||
1179 | /*** | |
1180 | * kick_process - kick a running thread to enter/exit the kernel | |
1181 | * @p: the to-be-kicked thread | |
1182 | * | |
1183 | * Cause a process which is running on another CPU to enter | |
1184 | * kernel-mode, without any delay. (to get signals handled.) | |
1185 | * | |
1186 | * NOTE: this function doesnt have to take the runqueue lock, | |
1187 | * because all it wants to ensure is that the remote task enters | |
1188 | * the kernel. If the IPI races and the task has been migrated | |
1189 | * to another CPU then no harm is done and the purpose has been | |
1190 | * achieved as well. | |
1191 | */ | |
36c8b586 | 1192 | void kick_process(struct task_struct *p) |
1da177e4 LT |
1193 | { |
1194 | int cpu; | |
1195 | ||
1196 | preempt_disable(); | |
1197 | cpu = task_cpu(p); | |
1198 | if ((cpu != smp_processor_id()) && task_curr(p)) | |
1199 | smp_send_reschedule(cpu); | |
1200 | preempt_enable(); | |
1201 | } | |
1202 | ||
1203 | /* | |
2dd73a4f PW |
1204 | * Return a low guess at the load of a migration-source cpu weighted |
1205 | * according to the scheduling class and "nice" value. | |
1da177e4 LT |
1206 | * |
1207 | * We want to under-estimate the load of migration sources, to | |
1208 | * balance conservatively. | |
1209 | */ | |
a2000572 | 1210 | static inline unsigned long source_load(int cpu, int type) |
1da177e4 | 1211 | { |
70b97a7f | 1212 | struct rq *rq = cpu_rq(cpu); |
dd41f596 | 1213 | unsigned long total = weighted_cpuload(cpu); |
2dd73a4f | 1214 | |
3b0bd9bc | 1215 | if (type == 0) |
dd41f596 | 1216 | return total; |
b910472d | 1217 | |
dd41f596 | 1218 | return min(rq->cpu_load[type-1], total); |
1da177e4 LT |
1219 | } |
1220 | ||
1221 | /* | |
2dd73a4f PW |
1222 | * Return a high guess at the load of a migration-target cpu weighted |
1223 | * according to the scheduling class and "nice" value. | |
1da177e4 | 1224 | */ |
a2000572 | 1225 | static inline unsigned long target_load(int cpu, int type) |
1da177e4 | 1226 | { |
70b97a7f | 1227 | struct rq *rq = cpu_rq(cpu); |
dd41f596 | 1228 | unsigned long total = weighted_cpuload(cpu); |
2dd73a4f | 1229 | |
7897986b | 1230 | if (type == 0) |
dd41f596 | 1231 | return total; |
3b0bd9bc | 1232 | |
dd41f596 | 1233 | return max(rq->cpu_load[type-1], total); |
2dd73a4f PW |
1234 | } |
1235 | ||
1236 | /* | |
1237 | * Return the average load per task on the cpu's run queue | |
1238 | */ | |
1239 | static inline unsigned long cpu_avg_load_per_task(int cpu) | |
1240 | { | |
70b97a7f | 1241 | struct rq *rq = cpu_rq(cpu); |
dd41f596 | 1242 | unsigned long total = weighted_cpuload(cpu); |
2dd73a4f PW |
1243 | unsigned long n = rq->nr_running; |
1244 | ||
dd41f596 | 1245 | return n ? total / n : SCHED_LOAD_SCALE; |
1da177e4 LT |
1246 | } |
1247 | ||
147cbb4b NP |
1248 | /* |
1249 | * find_idlest_group finds and returns the least busy CPU group within the | |
1250 | * domain. | |
1251 | */ | |
1252 | static struct sched_group * | |
1253 | find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu) | |
1254 | { | |
1255 | struct sched_group *idlest = NULL, *this = NULL, *group = sd->groups; | |
1256 | unsigned long min_load = ULONG_MAX, this_load = 0; | |
1257 | int load_idx = sd->forkexec_idx; | |
1258 | int imbalance = 100 + (sd->imbalance_pct-100)/2; | |
1259 | ||
1260 | do { | |
1261 | unsigned long load, avg_load; | |
1262 | int local_group; | |
1263 | int i; | |
1264 | ||
da5a5522 BD |
1265 | /* Skip over this group if it has no CPUs allowed */ |
1266 | if (!cpus_intersects(group->cpumask, p->cpus_allowed)) | |
1267 | goto nextgroup; | |
1268 | ||
147cbb4b | 1269 | local_group = cpu_isset(this_cpu, group->cpumask); |
147cbb4b NP |
1270 | |
1271 | /* Tally up the load of all CPUs in the group */ | |
1272 | avg_load = 0; | |
1273 | ||
1274 | for_each_cpu_mask(i, group->cpumask) { | |
1275 | /* Bias balancing toward cpus of our domain */ | |
1276 | if (local_group) | |
1277 | load = source_load(i, load_idx); | |
1278 | else | |
1279 | load = target_load(i, load_idx); | |
1280 | ||
1281 | avg_load += load; | |
1282 | } | |
1283 | ||
1284 | /* Adjust by relative CPU power of the group */ | |
5517d86b ED |
1285 | avg_load = sg_div_cpu_power(group, |
1286 | avg_load * SCHED_LOAD_SCALE); | |
147cbb4b NP |
1287 | |
1288 | if (local_group) { | |
1289 | this_load = avg_load; | |
1290 | this = group; | |
1291 | } else if (avg_load < min_load) { | |
1292 | min_load = avg_load; | |
1293 | idlest = group; | |
1294 | } | |
da5a5522 | 1295 | nextgroup: |
147cbb4b NP |
1296 | group = group->next; |
1297 | } while (group != sd->groups); | |
1298 | ||
1299 | if (!idlest || 100*this_load < imbalance*min_load) | |
1300 | return NULL; | |
1301 | return idlest; | |
1302 | } | |
1303 | ||
1304 | /* | |
0feaece9 | 1305 | * find_idlest_cpu - find the idlest cpu among the cpus in group. |
147cbb4b | 1306 | */ |
95cdf3b7 IM |
1307 | static int |
1308 | find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu) | |
147cbb4b | 1309 | { |
da5a5522 | 1310 | cpumask_t tmp; |
147cbb4b NP |
1311 | unsigned long load, min_load = ULONG_MAX; |
1312 | int idlest = -1; | |
1313 | int i; | |
1314 | ||
da5a5522 BD |
1315 | /* Traverse only the allowed CPUs */ |
1316 | cpus_and(tmp, group->cpumask, p->cpus_allowed); | |
1317 | ||
1318 | for_each_cpu_mask(i, tmp) { | |
2dd73a4f | 1319 | load = weighted_cpuload(i); |
147cbb4b NP |
1320 | |
1321 | if (load < min_load || (load == min_load && i == this_cpu)) { | |
1322 | min_load = load; | |
1323 | idlest = i; | |
1324 | } | |
1325 | } | |
1326 | ||
1327 | return idlest; | |
1328 | } | |
1329 | ||
476d139c NP |
1330 | /* |
1331 | * sched_balance_self: balance the current task (running on cpu) in domains | |
1332 | * that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and | |
1333 | * SD_BALANCE_EXEC. | |
1334 | * | |
1335 | * Balance, ie. select the least loaded group. | |
1336 | * | |
1337 | * Returns the target CPU number, or the same CPU if no balancing is needed. | |
1338 | * | |
1339 | * preempt must be disabled. | |
1340 | */ | |
1341 | static int sched_balance_self(int cpu, int flag) | |
1342 | { | |
1343 | struct task_struct *t = current; | |
1344 | struct sched_domain *tmp, *sd = NULL; | |
147cbb4b | 1345 | |
c96d145e | 1346 | for_each_domain(cpu, tmp) { |
5c45bf27 SS |
1347 | /* |
1348 | * If power savings logic is enabled for a domain, stop there. | |
1349 | */ | |
1350 | if (tmp->flags & SD_POWERSAVINGS_BALANCE) | |
1351 | break; | |
476d139c NP |
1352 | if (tmp->flags & flag) |
1353 | sd = tmp; | |
c96d145e | 1354 | } |
476d139c NP |
1355 | |
1356 | while (sd) { | |
1357 | cpumask_t span; | |
1358 | struct sched_group *group; | |
1a848870 SS |
1359 | int new_cpu, weight; |
1360 | ||
1361 | if (!(sd->flags & flag)) { | |
1362 | sd = sd->child; | |
1363 | continue; | |
1364 | } | |
476d139c NP |
1365 | |
1366 | span = sd->span; | |
1367 | group = find_idlest_group(sd, t, cpu); | |
1a848870 SS |
1368 | if (!group) { |
1369 | sd = sd->child; | |
1370 | continue; | |
1371 | } | |
476d139c | 1372 | |
da5a5522 | 1373 | new_cpu = find_idlest_cpu(group, t, cpu); |
1a848870 SS |
1374 | if (new_cpu == -1 || new_cpu == cpu) { |
1375 | /* Now try balancing at a lower domain level of cpu */ | |
1376 | sd = sd->child; | |
1377 | continue; | |
1378 | } | |
476d139c | 1379 | |
1a848870 | 1380 | /* Now try balancing at a lower domain level of new_cpu */ |
476d139c | 1381 | cpu = new_cpu; |
476d139c NP |
1382 | sd = NULL; |
1383 | weight = cpus_weight(span); | |
1384 | for_each_domain(cpu, tmp) { | |
1385 | if (weight <= cpus_weight(tmp->span)) | |
1386 | break; | |
1387 | if (tmp->flags & flag) | |
1388 | sd = tmp; | |
1389 | } | |
1390 | /* while loop will break here if sd == NULL */ | |
1391 | } | |
1392 | ||
1393 | return cpu; | |
1394 | } | |
1395 | ||
1396 | #endif /* CONFIG_SMP */ | |
1da177e4 LT |
1397 | |
1398 | /* | |
1399 | * wake_idle() will wake a task on an idle cpu if task->cpu is | |
1400 | * not idle and an idle cpu is available. The span of cpus to | |
1401 | * search starts with cpus closest then further out as needed, | |
1402 | * so we always favor a closer, idle cpu. | |
1403 | * | |
1404 | * Returns the CPU we should wake onto. | |
1405 | */ | |
1406 | #if defined(ARCH_HAS_SCHED_WAKE_IDLE) | |
36c8b586 | 1407 | static int wake_idle(int cpu, struct task_struct *p) |
1da177e4 LT |
1408 | { |
1409 | cpumask_t tmp; | |
1410 | struct sched_domain *sd; | |
1411 | int i; | |
1412 | ||
4953198b SS |
1413 | /* |
1414 | * If it is idle, then it is the best cpu to run this task. | |
1415 | * | |
1416 | * This cpu is also the best, if it has more than one task already. | |
1417 | * Siblings must be also busy(in most cases) as they didn't already | |
1418 | * pickup the extra load from this cpu and hence we need not check | |
1419 | * sibling runqueue info. This will avoid the checks and cache miss | |
1420 | * penalities associated with that. | |
1421 | */ | |
1422 | if (idle_cpu(cpu) || cpu_rq(cpu)->nr_running > 1) | |
1da177e4 LT |
1423 | return cpu; |
1424 | ||
1425 | for_each_domain(cpu, sd) { | |
1426 | if (sd->flags & SD_WAKE_IDLE) { | |
e0f364f4 | 1427 | cpus_and(tmp, sd->span, p->cpus_allowed); |
1da177e4 LT |
1428 | for_each_cpu_mask(i, tmp) { |
1429 | if (idle_cpu(i)) | |
1430 | return i; | |
1431 | } | |
1432 | } | |
e0f364f4 NP |
1433 | else |
1434 | break; | |
1da177e4 LT |
1435 | } |
1436 | return cpu; | |
1437 | } | |
1438 | #else | |
36c8b586 | 1439 | static inline int wake_idle(int cpu, struct task_struct *p) |
1da177e4 LT |
1440 | { |
1441 | return cpu; | |
1442 | } | |
1443 | #endif | |
1444 | ||
1445 | /*** | |
1446 | * try_to_wake_up - wake up a thread | |
1447 | * @p: the to-be-woken-up thread | |
1448 | * @state: the mask of task states that can be woken | |
1449 | * @sync: do a synchronous wakeup? | |
1450 | * | |
1451 | * Put it on the run-queue if it's not already there. The "current" | |
1452 | * thread is always on the run-queue (except when the actual | |
1453 | * re-schedule is in progress), and as such you're allowed to do | |
1454 | * the simpler "current->state = TASK_RUNNING" to mark yourself | |
1455 | * runnable without the overhead of this. | |
1456 | * | |
1457 | * returns failure only if the task is already active. | |
1458 | */ | |
36c8b586 | 1459 | static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync) |
1da177e4 LT |
1460 | { |
1461 | int cpu, this_cpu, success = 0; | |
1462 | unsigned long flags; | |
1463 | long old_state; | |
70b97a7f | 1464 | struct rq *rq; |
1da177e4 | 1465 | #ifdef CONFIG_SMP |
7897986b | 1466 | struct sched_domain *sd, *this_sd = NULL; |
70b97a7f | 1467 | unsigned long load, this_load; |
1da177e4 LT |
1468 | int new_cpu; |
1469 | #endif | |
1470 | ||
1471 | rq = task_rq_lock(p, &flags); | |
1472 | old_state = p->state; | |
1473 | if (!(old_state & state)) | |
1474 | goto out; | |
1475 | ||
dd41f596 | 1476 | if (p->se.on_rq) |
1da177e4 LT |
1477 | goto out_running; |
1478 | ||
1479 | cpu = task_cpu(p); | |
1480 | this_cpu = smp_processor_id(); | |
1481 | ||
1482 | #ifdef CONFIG_SMP | |
1483 | if (unlikely(task_running(rq, p))) | |
1484 | goto out_activate; | |
1485 | ||
7897986b NP |
1486 | new_cpu = cpu; |
1487 | ||
1da177e4 LT |
1488 | schedstat_inc(rq, ttwu_cnt); |
1489 | if (cpu == this_cpu) { | |
1490 | schedstat_inc(rq, ttwu_local); | |
7897986b NP |
1491 | goto out_set_cpu; |
1492 | } | |
1493 | ||
1494 | for_each_domain(this_cpu, sd) { | |
1495 | if (cpu_isset(cpu, sd->span)) { | |
1496 | schedstat_inc(sd, ttwu_wake_remote); | |
1497 | this_sd = sd; | |
1498 | break; | |
1da177e4 LT |
1499 | } |
1500 | } | |
1da177e4 | 1501 | |
7897986b | 1502 | if (unlikely(!cpu_isset(this_cpu, p->cpus_allowed))) |
1da177e4 LT |
1503 | goto out_set_cpu; |
1504 | ||
1da177e4 | 1505 | /* |
7897986b | 1506 | * Check for affine wakeup and passive balancing possibilities. |
1da177e4 | 1507 | */ |
7897986b NP |
1508 | if (this_sd) { |
1509 | int idx = this_sd->wake_idx; | |
1510 | unsigned int imbalance; | |
1da177e4 | 1511 | |
a3f21bce NP |
1512 | imbalance = 100 + (this_sd->imbalance_pct - 100) / 2; |
1513 | ||
7897986b NP |
1514 | load = source_load(cpu, idx); |
1515 | this_load = target_load(this_cpu, idx); | |
1da177e4 | 1516 | |
7897986b NP |
1517 | new_cpu = this_cpu; /* Wake to this CPU if we can */ |
1518 | ||
a3f21bce NP |
1519 | if (this_sd->flags & SD_WAKE_AFFINE) { |
1520 | unsigned long tl = this_load; | |
33859f7f MOS |
1521 | unsigned long tl_per_task; |
1522 | ||
1523 | tl_per_task = cpu_avg_load_per_task(this_cpu); | |
2dd73a4f | 1524 | |
1da177e4 | 1525 | /* |
a3f21bce NP |
1526 | * If sync wakeup then subtract the (maximum possible) |
1527 | * effect of the currently running task from the load | |
1528 | * of the current CPU: | |
1da177e4 | 1529 | */ |
a3f21bce | 1530 | if (sync) |
dd41f596 | 1531 | tl -= current->se.load.weight; |
a3f21bce NP |
1532 | |
1533 | if ((tl <= load && | |
2dd73a4f | 1534 | tl + target_load(cpu, idx) <= tl_per_task) || |
dd41f596 | 1535 | 100*(tl + p->se.load.weight) <= imbalance*load) { |
a3f21bce NP |
1536 | /* |
1537 | * This domain has SD_WAKE_AFFINE and | |
1538 | * p is cache cold in this domain, and | |
1539 | * there is no bad imbalance. | |
1540 | */ | |
1541 | schedstat_inc(this_sd, ttwu_move_affine); | |
1542 | goto out_set_cpu; | |
1543 | } | |
1544 | } | |
1545 | ||
1546 | /* | |
1547 | * Start passive balancing when half the imbalance_pct | |
1548 | * limit is reached. | |
1549 | */ | |
1550 | if (this_sd->flags & SD_WAKE_BALANCE) { | |
1551 | if (imbalance*this_load <= 100*load) { | |
1552 | schedstat_inc(this_sd, ttwu_move_balance); | |
1553 | goto out_set_cpu; | |
1554 | } | |
1da177e4 LT |
1555 | } |
1556 | } | |
1557 | ||
1558 | new_cpu = cpu; /* Could not wake to this_cpu. Wake to cpu instead */ | |
1559 | out_set_cpu: | |
1560 | new_cpu = wake_idle(new_cpu, p); | |
1561 | if (new_cpu != cpu) { | |
1562 | set_task_cpu(p, new_cpu); | |
1563 | task_rq_unlock(rq, &flags); | |
1564 | /* might preempt at this point */ | |
1565 | rq = task_rq_lock(p, &flags); | |
1566 | old_state = p->state; | |
1567 | if (!(old_state & state)) | |
1568 | goto out; | |
dd41f596 | 1569 | if (p->se.on_rq) |
1da177e4 LT |
1570 | goto out_running; |
1571 | ||
1572 | this_cpu = smp_processor_id(); | |
1573 | cpu = task_cpu(p); | |
1574 | } | |
1575 | ||
1576 | out_activate: | |
1577 | #endif /* CONFIG_SMP */ | |
dd41f596 | 1578 | activate_task(rq, p, 1); |
1da177e4 LT |
1579 | /* |
1580 | * Sync wakeups (i.e. those types of wakeups where the waker | |
1581 | * has indicated that it will leave the CPU in short order) | |
1582 | * don't trigger a preemption, if the woken up task will run on | |
1583 | * this cpu. (in this case the 'I will reschedule' promise of | |
1584 | * the waker guarantees that the freshly woken up task is going | |
1585 | * to be considered on this CPU.) | |
1586 | */ | |
dd41f596 IM |
1587 | if (!sync || cpu != this_cpu) |
1588 | check_preempt_curr(rq, p); | |
1da177e4 LT |
1589 | success = 1; |
1590 | ||
1591 | out_running: | |
1592 | p->state = TASK_RUNNING; | |
1593 | out: | |
1594 | task_rq_unlock(rq, &flags); | |
1595 | ||
1596 | return success; | |
1597 | } | |
1598 | ||
36c8b586 | 1599 | int fastcall wake_up_process(struct task_struct *p) |
1da177e4 LT |
1600 | { |
1601 | return try_to_wake_up(p, TASK_STOPPED | TASK_TRACED | | |
1602 | TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE, 0); | |
1603 | } | |
1da177e4 LT |
1604 | EXPORT_SYMBOL(wake_up_process); |
1605 | ||
36c8b586 | 1606 | int fastcall wake_up_state(struct task_struct *p, unsigned int state) |
1da177e4 LT |
1607 | { |
1608 | return try_to_wake_up(p, state, 0); | |
1609 | } | |
1610 | ||
1da177e4 LT |
1611 | /* |
1612 | * Perform scheduler related setup for a newly forked process p. | |
1613 | * p is forked by current. | |
dd41f596 IM |
1614 | * |
1615 | * __sched_fork() is basic setup used by init_idle() too: | |
1616 | */ | |
1617 | static void __sched_fork(struct task_struct *p) | |
1618 | { | |
1619 | p->se.wait_start_fair = 0; | |
1620 | p->se.wait_start = 0; | |
1621 | p->se.exec_start = 0; | |
1622 | p->se.sum_exec_runtime = 0; | |
1623 | p->se.delta_exec = 0; | |
1624 | p->se.delta_fair_run = 0; | |
1625 | p->se.delta_fair_sleep = 0; | |
1626 | p->se.wait_runtime = 0; | |
1627 | p->se.sum_wait_runtime = 0; | |
1628 | p->se.sum_sleep_runtime = 0; | |
1629 | p->se.sleep_start = 0; | |
1630 | p->se.sleep_start_fair = 0; | |
1631 | p->se.block_start = 0; | |
1632 | p->se.sleep_max = 0; | |
1633 | p->se.block_max = 0; | |
1634 | p->se.exec_max = 0; | |
1635 | p->se.wait_max = 0; | |
1636 | p->se.wait_runtime_overruns = 0; | |
1637 | p->se.wait_runtime_underruns = 0; | |
476d139c | 1638 | |
dd41f596 IM |
1639 | INIT_LIST_HEAD(&p->run_list); |
1640 | p->se.on_rq = 0; | |
476d139c | 1641 | |
1da177e4 LT |
1642 | /* |
1643 | * We mark the process as running here, but have not actually | |
1644 | * inserted it onto the runqueue yet. This guarantees that | |
1645 | * nobody will actually run it, and a signal or other external | |
1646 | * event cannot wake it up and insert it on the runqueue either. | |
1647 | */ | |
1648 | p->state = TASK_RUNNING; | |
dd41f596 IM |
1649 | } |
1650 | ||
1651 | /* | |
1652 | * fork()/clone()-time setup: | |
1653 | */ | |
1654 | void sched_fork(struct task_struct *p, int clone_flags) | |
1655 | { | |
1656 | int cpu = get_cpu(); | |
1657 | ||
1658 | __sched_fork(p); | |
1659 | ||
1660 | #ifdef CONFIG_SMP | |
1661 | cpu = sched_balance_self(cpu, SD_BALANCE_FORK); | |
1662 | #endif | |
1663 | __set_task_cpu(p, cpu); | |
b29739f9 IM |
1664 | |
1665 | /* | |
1666 | * Make sure we do not leak PI boosting priority to the child: | |
1667 | */ | |
1668 | p->prio = current->normal_prio; | |
1669 | ||
52f17b6c | 1670 | #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) |
dd41f596 | 1671 | if (likely(sched_info_on())) |
52f17b6c | 1672 | memset(&p->sched_info, 0, sizeof(p->sched_info)); |
1da177e4 | 1673 | #endif |
d6077cb8 | 1674 | #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW) |
4866cde0 NP |
1675 | p->oncpu = 0; |
1676 | #endif | |
1da177e4 | 1677 | #ifdef CONFIG_PREEMPT |
4866cde0 | 1678 | /* Want to start with kernel preemption disabled. */ |
a1261f54 | 1679 | task_thread_info(p)->preempt_count = 1; |
1da177e4 | 1680 | #endif |
476d139c | 1681 | put_cpu(); |
1da177e4 LT |
1682 | } |
1683 | ||
dd41f596 IM |
1684 | /* |
1685 | * After fork, child runs first. (default) If set to 0 then | |
1686 | * parent will (try to) run first. | |
1687 | */ | |
1688 | unsigned int __read_mostly sysctl_sched_child_runs_first = 1; | |
1689 | ||
1da177e4 LT |
1690 | /* |
1691 | * wake_up_new_task - wake up a newly created task for the first time. | |
1692 | * | |
1693 | * This function will do some initial scheduler statistics housekeeping | |
1694 | * that must be done for every newly created context, then puts the task | |
1695 | * on the runqueue and wakes it. | |
1696 | */ | |
36c8b586 | 1697 | void fastcall wake_up_new_task(struct task_struct *p, unsigned long clone_flags) |
1da177e4 LT |
1698 | { |
1699 | unsigned long flags; | |
dd41f596 IM |
1700 | struct rq *rq; |
1701 | int this_cpu; | |
1da177e4 LT |
1702 | |
1703 | rq = task_rq_lock(p, &flags); | |
147cbb4b | 1704 | BUG_ON(p->state != TASK_RUNNING); |
dd41f596 | 1705 | this_cpu = smp_processor_id(); /* parent's CPU */ |
1da177e4 LT |
1706 | |
1707 | p->prio = effective_prio(p); | |
1708 | ||
dd41f596 IM |
1709 | if (!sysctl_sched_child_runs_first || (clone_flags & CLONE_VM) || |
1710 | task_cpu(p) != this_cpu || !current->se.on_rq) { | |
1711 | activate_task(rq, p, 0); | |
1da177e4 | 1712 | } else { |
1da177e4 | 1713 | /* |
dd41f596 IM |
1714 | * Let the scheduling class do new task startup |
1715 | * management (if any): | |
1da177e4 | 1716 | */ |
dd41f596 | 1717 | p->sched_class->task_new(rq, p); |
1da177e4 | 1718 | } |
dd41f596 IM |
1719 | check_preempt_curr(rq, p); |
1720 | task_rq_unlock(rq, &flags); | |
1da177e4 LT |
1721 | } |
1722 | ||
4866cde0 NP |
1723 | /** |
1724 | * prepare_task_switch - prepare to switch tasks | |
1725 | * @rq: the runqueue preparing to switch | |
1726 | * @next: the task we are going to switch to. | |
1727 | * | |
1728 | * This is called with the rq lock held and interrupts off. It must | |
1729 | * be paired with a subsequent finish_task_switch after the context | |
1730 | * switch. | |
1731 | * | |
1732 | * prepare_task_switch sets up locking and calls architecture specific | |
1733 | * hooks. | |
1734 | */ | |
70b97a7f | 1735 | static inline void prepare_task_switch(struct rq *rq, struct task_struct *next) |
4866cde0 NP |
1736 | { |
1737 | prepare_lock_switch(rq, next); | |
1738 | prepare_arch_switch(next); | |
1739 | } | |
1740 | ||
1da177e4 LT |
1741 | /** |
1742 | * finish_task_switch - clean up after a task-switch | |
344babaa | 1743 | * @rq: runqueue associated with task-switch |
1da177e4 LT |
1744 | * @prev: the thread we just switched away from. |
1745 | * | |
4866cde0 NP |
1746 | * finish_task_switch must be called after the context switch, paired |
1747 | * with a prepare_task_switch call before the context switch. | |
1748 | * finish_task_switch will reconcile locking set up by prepare_task_switch, | |
1749 | * and do any other architecture-specific cleanup actions. | |
1da177e4 LT |
1750 | * |
1751 | * Note that we may have delayed dropping an mm in context_switch(). If | |
1752 | * so, we finish that here outside of the runqueue lock. (Doing it | |
1753 | * with the lock held can cause deadlocks; see schedule() for | |
1754 | * details.) | |
1755 | */ | |
70b97a7f | 1756 | static inline void finish_task_switch(struct rq *rq, struct task_struct *prev) |
1da177e4 LT |
1757 | __releases(rq->lock) |
1758 | { | |
1da177e4 | 1759 | struct mm_struct *mm = rq->prev_mm; |
55a101f8 | 1760 | long prev_state; |
1da177e4 LT |
1761 | |
1762 | rq->prev_mm = NULL; | |
1763 | ||
1764 | /* | |
1765 | * A task struct has one reference for the use as "current". | |
c394cc9f | 1766 | * If a task dies, then it sets TASK_DEAD in tsk->state and calls |
55a101f8 ON |
1767 | * schedule one last time. The schedule call will never return, and |
1768 | * the scheduled task must drop that reference. | |
c394cc9f | 1769 | * The test for TASK_DEAD must occur while the runqueue locks are |
1da177e4 LT |
1770 | * still held, otherwise prev could be scheduled on another cpu, die |
1771 | * there before we look at prev->state, and then the reference would | |
1772 | * be dropped twice. | |
1773 | * Manfred Spraul <manfred@colorfullife.com> | |
1774 | */ | |
55a101f8 | 1775 | prev_state = prev->state; |
4866cde0 NP |
1776 | finish_arch_switch(prev); |
1777 | finish_lock_switch(rq, prev); | |
1da177e4 LT |
1778 | if (mm) |
1779 | mmdrop(mm); | |
c394cc9f | 1780 | if (unlikely(prev_state == TASK_DEAD)) { |
c6fd91f0 | 1781 | /* |
1782 | * Remove function-return probe instances associated with this | |
1783 | * task and put them back on the free list. | |
1784 | */ | |
1785 | kprobe_flush_task(prev); | |
1da177e4 | 1786 | put_task_struct(prev); |
c6fd91f0 | 1787 | } |
1da177e4 LT |
1788 | } |
1789 | ||
1790 | /** | |
1791 | * schedule_tail - first thing a freshly forked thread must call. | |
1792 | * @prev: the thread we just switched away from. | |
1793 | */ | |
36c8b586 | 1794 | asmlinkage void schedule_tail(struct task_struct *prev) |
1da177e4 LT |
1795 | __releases(rq->lock) |
1796 | { | |
70b97a7f IM |
1797 | struct rq *rq = this_rq(); |
1798 | ||
4866cde0 NP |
1799 | finish_task_switch(rq, prev); |
1800 | #ifdef __ARCH_WANT_UNLOCKED_CTXSW | |
1801 | /* In this case, finish_task_switch does not reenable preemption */ | |
1802 | preempt_enable(); | |
1803 | #endif | |
1da177e4 LT |
1804 | if (current->set_child_tid) |
1805 | put_user(current->pid, current->set_child_tid); | |
1806 | } | |
1807 | ||
1808 | /* | |
1809 | * context_switch - switch to the new MM and the new | |
1810 | * thread's register state. | |
1811 | */ | |
dd41f596 | 1812 | static inline void |
70b97a7f | 1813 | context_switch(struct rq *rq, struct task_struct *prev, |
36c8b586 | 1814 | struct task_struct *next) |
1da177e4 | 1815 | { |
dd41f596 | 1816 | struct mm_struct *mm, *oldmm; |
1da177e4 | 1817 | |
dd41f596 IM |
1818 | prepare_task_switch(rq, next); |
1819 | mm = next->mm; | |
1820 | oldmm = prev->active_mm; | |
9226d125 ZA |
1821 | /* |
1822 | * For paravirt, this is coupled with an exit in switch_to to | |
1823 | * combine the page table reload and the switch backend into | |
1824 | * one hypercall. | |
1825 | */ | |
1826 | arch_enter_lazy_cpu_mode(); | |
1827 | ||
dd41f596 | 1828 | if (unlikely(!mm)) { |
1da177e4 LT |
1829 | next->active_mm = oldmm; |
1830 | atomic_inc(&oldmm->mm_count); | |
1831 | enter_lazy_tlb(oldmm, next); | |
1832 | } else | |
1833 | switch_mm(oldmm, mm, next); | |
1834 | ||
dd41f596 | 1835 | if (unlikely(!prev->mm)) { |
1da177e4 | 1836 | prev->active_mm = NULL; |
1da177e4 LT |
1837 | rq->prev_mm = oldmm; |
1838 | } | |
3a5f5e48 IM |
1839 | /* |
1840 | * Since the runqueue lock will be released by the next | |
1841 | * task (which is an invalid locking op but in the case | |
1842 | * of the scheduler it's an obvious special-case), so we | |
1843 | * do an early lockdep release here: | |
1844 | */ | |
1845 | #ifndef __ARCH_WANT_UNLOCKED_CTXSW | |
8a25d5de | 1846 | spin_release(&rq->lock.dep_map, 1, _THIS_IP_); |
3a5f5e48 | 1847 | #endif |
1da177e4 LT |
1848 | |
1849 | /* Here we just switch the register state and the stack. */ | |
1850 | switch_to(prev, next, prev); | |
1851 | ||
dd41f596 IM |
1852 | barrier(); |
1853 | /* | |
1854 | * this_rq must be evaluated again because prev may have moved | |
1855 | * CPUs since it called schedule(), thus the 'rq' on its stack | |
1856 | * frame will be invalid. | |
1857 | */ | |
1858 | finish_task_switch(this_rq(), prev); | |
1da177e4 LT |
1859 | } |
1860 | ||
1861 | /* | |
1862 | * nr_running, nr_uninterruptible and nr_context_switches: | |
1863 | * | |
1864 | * externally visible scheduler statistics: current number of runnable | |
1865 | * threads, current number of uninterruptible-sleeping threads, total | |
1866 | * number of context switches performed since bootup. | |
1867 | */ | |
1868 | unsigned long nr_running(void) | |
1869 | { | |
1870 | unsigned long i, sum = 0; | |
1871 | ||
1872 | for_each_online_cpu(i) | |
1873 | sum += cpu_rq(i)->nr_running; | |
1874 | ||
1875 | return sum; | |
1876 | } | |
1877 | ||
1878 | unsigned long nr_uninterruptible(void) | |
1879 | { | |
1880 | unsigned long i, sum = 0; | |
1881 | ||
0a945022 | 1882 | for_each_possible_cpu(i) |
1da177e4 LT |
1883 | sum += cpu_rq(i)->nr_uninterruptible; |
1884 | ||
1885 | /* | |
1886 | * Since we read the counters lockless, it might be slightly | |
1887 | * inaccurate. Do not allow it to go below zero though: | |
1888 | */ | |
1889 | if (unlikely((long)sum < 0)) | |
1890 | sum = 0; | |
1891 | ||
1892 | return sum; | |
1893 | } | |
1894 | ||
1895 | unsigned long long nr_context_switches(void) | |
1896 | { | |
cc94abfc SR |
1897 | int i; |
1898 | unsigned long long sum = 0; | |
1da177e4 | 1899 | |
0a945022 | 1900 | for_each_possible_cpu(i) |
1da177e4 LT |
1901 | sum += cpu_rq(i)->nr_switches; |
1902 | ||
1903 | return sum; | |
1904 | } | |
1905 | ||
1906 | unsigned long nr_iowait(void) | |
1907 | { | |
1908 | unsigned long i, sum = 0; | |
1909 | ||
0a945022 | 1910 | for_each_possible_cpu(i) |
1da177e4 LT |
1911 | sum += atomic_read(&cpu_rq(i)->nr_iowait); |
1912 | ||
1913 | return sum; | |
1914 | } | |
1915 | ||
db1b1fef JS |
1916 | unsigned long nr_active(void) |
1917 | { | |
1918 | unsigned long i, running = 0, uninterruptible = 0; | |
1919 | ||
1920 | for_each_online_cpu(i) { | |
1921 | running += cpu_rq(i)->nr_running; | |
1922 | uninterruptible += cpu_rq(i)->nr_uninterruptible; | |
1923 | } | |
1924 | ||
1925 | if (unlikely((long)uninterruptible < 0)) | |
1926 | uninterruptible = 0; | |
1927 | ||
1928 | return running + uninterruptible; | |
1929 | } | |
1930 | ||
48f24c4d | 1931 | /* |
dd41f596 IM |
1932 | * Update rq->cpu_load[] statistics. This function is usually called every |
1933 | * scheduler tick (TICK_NSEC). | |
48f24c4d | 1934 | */ |
dd41f596 | 1935 | static void update_cpu_load(struct rq *this_rq) |
48f24c4d | 1936 | { |
dd41f596 IM |
1937 | u64 fair_delta64, exec_delta64, idle_delta64, sample_interval64, tmp64; |
1938 | unsigned long total_load = this_rq->ls.load.weight; | |
1939 | unsigned long this_load = total_load; | |
1940 | struct load_stat *ls = &this_rq->ls; | |
1941 | u64 now = __rq_clock(this_rq); | |
1942 | int i, scale; | |
1943 | ||
1944 | this_rq->nr_load_updates++; | |
1945 | if (unlikely(!(sysctl_sched_features & SCHED_FEAT_PRECISE_CPU_LOAD))) | |
1946 | goto do_avg; | |
1947 | ||
1948 | /* Update delta_fair/delta_exec fields first */ | |
1949 | update_curr_load(this_rq, now); | |
1950 | ||
1951 | fair_delta64 = ls->delta_fair + 1; | |
1952 | ls->delta_fair = 0; | |
1953 | ||
1954 | exec_delta64 = ls->delta_exec + 1; | |
1955 | ls->delta_exec = 0; | |
1956 | ||
1957 | sample_interval64 = now - ls->load_update_last; | |
1958 | ls->load_update_last = now; | |
1959 | ||
1960 | if ((s64)sample_interval64 < (s64)TICK_NSEC) | |
1961 | sample_interval64 = TICK_NSEC; | |
1962 | ||
1963 | if (exec_delta64 > sample_interval64) | |
1964 | exec_delta64 = sample_interval64; | |
1965 | ||
1966 | idle_delta64 = sample_interval64 - exec_delta64; | |
1967 | ||
1968 | tmp64 = div64_64(SCHED_LOAD_SCALE * exec_delta64, fair_delta64); | |
1969 | tmp64 = div64_64(tmp64 * exec_delta64, sample_interval64); | |
1970 | ||
1971 | this_load = (unsigned long)tmp64; | |
1972 | ||
1973 | do_avg: | |
1974 | ||
1975 | /* Update our load: */ | |
1976 | for (i = 0, scale = 1; i < CPU_LOAD_IDX_MAX; i++, scale += scale) { | |
1977 | unsigned long old_load, new_load; | |
1978 | ||
1979 | /* scale is effectively 1 << i now, and >> i divides by scale */ | |
1980 | ||
1981 | old_load = this_rq->cpu_load[i]; | |
1982 | new_load = this_load; | |
1983 | ||
1984 | this_rq->cpu_load[i] = (old_load*(scale-1) + new_load) >> i; | |
1985 | } | |
48f24c4d IM |
1986 | } |
1987 | ||
dd41f596 IM |
1988 | #ifdef CONFIG_SMP |
1989 | ||
1da177e4 LT |
1990 | /* |
1991 | * double_rq_lock - safely lock two runqueues | |
1992 | * | |
1993 | * Note this does not disable interrupts like task_rq_lock, | |
1994 | * you need to do so manually before calling. | |
1995 | */ | |
70b97a7f | 1996 | static void double_rq_lock(struct rq *rq1, struct rq *rq2) |
1da177e4 LT |
1997 | __acquires(rq1->lock) |
1998 | __acquires(rq2->lock) | |
1999 | { | |
054b9108 | 2000 | BUG_ON(!irqs_disabled()); |
1da177e4 LT |
2001 | if (rq1 == rq2) { |
2002 | spin_lock(&rq1->lock); | |
2003 | __acquire(rq2->lock); /* Fake it out ;) */ | |
2004 | } else { | |
c96d145e | 2005 | if (rq1 < rq2) { |
1da177e4 LT |
2006 | spin_lock(&rq1->lock); |
2007 | spin_lock(&rq2->lock); | |
2008 | } else { | |
2009 | spin_lock(&rq2->lock); | |
2010 | spin_lock(&rq1->lock); | |
2011 | } | |
2012 | } | |
2013 | } | |
2014 | ||
2015 | /* | |
2016 | * double_rq_unlock - safely unlock two runqueues | |
2017 | * | |
2018 | * Note this does not restore interrupts like task_rq_unlock, | |
2019 | * you need to do so manually after calling. | |
2020 | */ | |
70b97a7f | 2021 | static void double_rq_unlock(struct rq *rq1, struct rq *rq2) |
1da177e4 LT |
2022 | __releases(rq1->lock) |
2023 | __releases(rq2->lock) | |
2024 | { | |
2025 | spin_unlock(&rq1->lock); | |
2026 | if (rq1 != rq2) | |
2027 | spin_unlock(&rq2->lock); | |
2028 | else | |
2029 | __release(rq2->lock); | |
2030 | } | |
2031 | ||
2032 | /* | |
2033 | * double_lock_balance - lock the busiest runqueue, this_rq is locked already. | |
2034 | */ | |
70b97a7f | 2035 | static void double_lock_balance(struct rq *this_rq, struct rq *busiest) |
1da177e4 LT |
2036 | __releases(this_rq->lock) |
2037 | __acquires(busiest->lock) | |
2038 | __acquires(this_rq->lock) | |
2039 | { | |
054b9108 KK |
2040 | if (unlikely(!irqs_disabled())) { |
2041 | /* printk() doesn't work good under rq->lock */ | |
2042 | spin_unlock(&this_rq->lock); | |
2043 | BUG_ON(1); | |
2044 | } | |
1da177e4 | 2045 | if (unlikely(!spin_trylock(&busiest->lock))) { |
c96d145e | 2046 | if (busiest < this_rq) { |
1da177e4 LT |
2047 | spin_unlock(&this_rq->lock); |
2048 | spin_lock(&busiest->lock); | |
2049 | spin_lock(&this_rq->lock); | |
2050 | } else | |
2051 | spin_lock(&busiest->lock); | |
2052 | } | |
2053 | } | |
2054 | ||
1da177e4 LT |
2055 | /* |
2056 | * If dest_cpu is allowed for this process, migrate the task to it. | |
2057 | * This is accomplished by forcing the cpu_allowed mask to only | |
2058 | * allow dest_cpu, which will force the cpu onto dest_cpu. Then | |
2059 | * the cpu_allowed mask is restored. | |
2060 | */ | |
36c8b586 | 2061 | static void sched_migrate_task(struct task_struct *p, int dest_cpu) |
1da177e4 | 2062 | { |
70b97a7f | 2063 | struct migration_req req; |
1da177e4 | 2064 | unsigned long flags; |
70b97a7f | 2065 | struct rq *rq; |
1da177e4 LT |
2066 | |
2067 | rq = task_rq_lock(p, &flags); | |
2068 | if (!cpu_isset(dest_cpu, p->cpus_allowed) | |
2069 | || unlikely(cpu_is_offline(dest_cpu))) | |
2070 | goto out; | |
2071 | ||
2072 | /* force the process onto the specified CPU */ | |
2073 | if (migrate_task(p, dest_cpu, &req)) { | |
2074 | /* Need to wait for migration thread (might exit: take ref). */ | |
2075 | struct task_struct *mt = rq->migration_thread; | |
36c8b586 | 2076 | |
1da177e4 LT |
2077 | get_task_struct(mt); |
2078 | task_rq_unlock(rq, &flags); | |
2079 | wake_up_process(mt); | |
2080 | put_task_struct(mt); | |
2081 | wait_for_completion(&req.done); | |
36c8b586 | 2082 | |
1da177e4 LT |
2083 | return; |
2084 | } | |
2085 | out: | |
2086 | task_rq_unlock(rq, &flags); | |
2087 | } | |
2088 | ||
2089 | /* | |
476d139c NP |
2090 | * sched_exec - execve() is a valuable balancing opportunity, because at |
2091 | * this point the task has the smallest effective memory and cache footprint. | |
1da177e4 LT |
2092 | */ |
2093 | void sched_exec(void) | |
2094 | { | |
1da177e4 | 2095 | int new_cpu, this_cpu = get_cpu(); |
476d139c | 2096 | new_cpu = sched_balance_self(this_cpu, SD_BALANCE_EXEC); |
1da177e4 | 2097 | put_cpu(); |
476d139c NP |
2098 | if (new_cpu != this_cpu) |
2099 | sched_migrate_task(current, new_cpu); | |
1da177e4 LT |
2100 | } |
2101 | ||
2102 | /* | |
2103 | * pull_task - move a task from a remote runqueue to the local runqueue. | |
2104 | * Both runqueues must be locked. | |
2105 | */ | |
dd41f596 IM |
2106 | static void pull_task(struct rq *src_rq, struct task_struct *p, |
2107 | struct rq *this_rq, int this_cpu) | |
1da177e4 | 2108 | { |
dd41f596 | 2109 | deactivate_task(src_rq, p, 0); |
1da177e4 | 2110 | set_task_cpu(p, this_cpu); |
dd41f596 | 2111 | activate_task(this_rq, p, 0); |
1da177e4 LT |
2112 | /* |
2113 | * Note that idle threads have a prio of MAX_PRIO, for this test | |
2114 | * to be always true for them. | |
2115 | */ | |
dd41f596 | 2116 | check_preempt_curr(this_rq, p); |
1da177e4 LT |
2117 | } |
2118 | ||
2119 | /* | |
2120 | * can_migrate_task - may task p from runqueue rq be migrated to this_cpu? | |
2121 | */ | |
858119e1 | 2122 | static |
70b97a7f | 2123 | int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu, |
d15bcfdb | 2124 | struct sched_domain *sd, enum cpu_idle_type idle, |
95cdf3b7 | 2125 | int *all_pinned) |
1da177e4 LT |
2126 | { |
2127 | /* | |
2128 | * We do not migrate tasks that are: | |
2129 | * 1) running (obviously), or | |
2130 | * 2) cannot be migrated to this CPU due to cpus_allowed, or | |
2131 | * 3) are cache-hot on their current CPU. | |
2132 | */ | |
1da177e4 LT |
2133 | if (!cpu_isset(this_cpu, p->cpus_allowed)) |
2134 | return 0; | |
81026794 NP |
2135 | *all_pinned = 0; |
2136 | ||
2137 | if (task_running(rq, p)) | |
2138 | return 0; | |
1da177e4 LT |
2139 | |
2140 | /* | |
dd41f596 | 2141 | * Aggressive migration if too many balance attempts have failed: |
1da177e4 | 2142 | */ |
dd41f596 | 2143 | if (sd->nr_balance_failed > sd->cache_nice_tries) |
1da177e4 LT |
2144 | return 1; |
2145 | ||
1da177e4 LT |
2146 | return 1; |
2147 | } | |
2148 | ||
dd41f596 | 2149 | static int balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, |
2dd73a4f | 2150 | unsigned long max_nr_move, unsigned long max_load_move, |
d15bcfdb | 2151 | struct sched_domain *sd, enum cpu_idle_type idle, |
dd41f596 IM |
2152 | int *all_pinned, unsigned long *load_moved, |
2153 | int this_best_prio, int best_prio, int best_prio_seen, | |
2154 | struct rq_iterator *iterator) | |
1da177e4 | 2155 | { |
dd41f596 IM |
2156 | int pulled = 0, pinned = 0, skip_for_load; |
2157 | struct task_struct *p; | |
2158 | long rem_load_move = max_load_move; | |
1da177e4 | 2159 | |
2dd73a4f | 2160 | if (max_nr_move == 0 || max_load_move == 0) |
1da177e4 LT |
2161 | goto out; |
2162 | ||
81026794 NP |
2163 | pinned = 1; |
2164 | ||
1da177e4 | 2165 | /* |
dd41f596 | 2166 | * Start the load-balancing iterator: |
1da177e4 | 2167 | */ |
dd41f596 IM |
2168 | p = iterator->start(iterator->arg); |
2169 | next: | |
2170 | if (!p) | |
1da177e4 | 2171 | goto out; |
50ddd969 PW |
2172 | /* |
2173 | * To help distribute high priority tasks accross CPUs we don't | |
2174 | * skip a task if it will be the highest priority task (i.e. smallest | |
2175 | * prio value) on its new queue regardless of its load weight | |
2176 | */ | |
dd41f596 IM |
2177 | skip_for_load = (p->se.load.weight >> 1) > rem_load_move + |
2178 | SCHED_LOAD_SCALE_FUZZ; | |
2179 | if (skip_for_load && p->prio < this_best_prio) | |
2180 | skip_for_load = !best_prio_seen && p->prio == best_prio; | |
615052dc | 2181 | if (skip_for_load || |
dd41f596 | 2182 | !can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) { |
48f24c4d | 2183 | |
dd41f596 IM |
2184 | best_prio_seen |= p->prio == best_prio; |
2185 | p = iterator->next(iterator->arg); | |
2186 | goto next; | |
1da177e4 LT |
2187 | } |
2188 | ||
dd41f596 | 2189 | pull_task(busiest, p, this_rq, this_cpu); |
1da177e4 | 2190 | pulled++; |
dd41f596 | 2191 | rem_load_move -= p->se.load.weight; |
1da177e4 | 2192 | |
2dd73a4f PW |
2193 | /* |
2194 | * We only want to steal up to the prescribed number of tasks | |
2195 | * and the prescribed amount of weighted load. | |
2196 | */ | |
2197 | if (pulled < max_nr_move && rem_load_move > 0) { | |
dd41f596 IM |
2198 | if (p->prio < this_best_prio) |
2199 | this_best_prio = p->prio; | |
2200 | p = iterator->next(iterator->arg); | |
2201 | goto next; | |
1da177e4 LT |
2202 | } |
2203 | out: | |
2204 | /* | |
2205 | * Right now, this is the only place pull_task() is called, | |
2206 | * so we can safely collect pull_task() stats here rather than | |
2207 | * inside pull_task(). | |
2208 | */ | |
2209 | schedstat_add(sd, lb_gained[idle], pulled); | |
81026794 NP |
2210 | |
2211 | if (all_pinned) | |
2212 | *all_pinned = pinned; | |
dd41f596 | 2213 | *load_moved = max_load_move - rem_load_move; |
1da177e4 LT |
2214 | return pulled; |
2215 | } | |
2216 | ||
dd41f596 IM |
2217 | /* |
2218 | * move_tasks tries to move up to max_nr_move tasks and max_load_move weighted | |
2219 | * load from busiest to this_rq, as part of a balancing operation within | |
2220 | * "domain". Returns the number of tasks moved. | |
2221 | * | |
2222 | * Called with both runqueues locked. | |
2223 | */ | |
2224 | static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
2225 | unsigned long max_nr_move, unsigned long max_load_move, | |
2226 | struct sched_domain *sd, enum cpu_idle_type idle, | |
2227 | int *all_pinned) | |
2228 | { | |
2229 | struct sched_class *class = sched_class_highest; | |
2230 | unsigned long load_moved, total_nr_moved = 0, nr_moved; | |
2231 | long rem_load_move = max_load_move; | |
2232 | ||
2233 | do { | |
2234 | nr_moved = class->load_balance(this_rq, this_cpu, busiest, | |
2235 | max_nr_move, (unsigned long)rem_load_move, | |
2236 | sd, idle, all_pinned, &load_moved); | |
2237 | total_nr_moved += nr_moved; | |
2238 | max_nr_move -= nr_moved; | |
2239 | rem_load_move -= load_moved; | |
2240 | class = class->next; | |
2241 | } while (class && max_nr_move && rem_load_move > 0); | |
2242 | ||
2243 | return total_nr_moved; | |
2244 | } | |
2245 | ||
1da177e4 LT |
2246 | /* |
2247 | * find_busiest_group finds and returns the busiest CPU group within the | |
48f24c4d IM |
2248 | * domain. It calculates and returns the amount of weighted load which |
2249 | * should be moved to restore balance via the imbalance parameter. | |
1da177e4 LT |
2250 | */ |
2251 | static struct sched_group * | |
2252 | find_busiest_group(struct sched_domain *sd, int this_cpu, | |
dd41f596 IM |
2253 | unsigned long *imbalance, enum cpu_idle_type idle, |
2254 | int *sd_idle, cpumask_t *cpus, int *balance) | |
1da177e4 LT |
2255 | { |
2256 | struct sched_group *busiest = NULL, *this = NULL, *group = sd->groups; | |
2257 | unsigned long max_load, avg_load, total_load, this_load, total_pwr; | |
0c117f1b | 2258 | unsigned long max_pull; |
2dd73a4f PW |
2259 | unsigned long busiest_load_per_task, busiest_nr_running; |
2260 | unsigned long this_load_per_task, this_nr_running; | |
7897986b | 2261 | int load_idx; |
5c45bf27 SS |
2262 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) |
2263 | int power_savings_balance = 1; | |
2264 | unsigned long leader_nr_running = 0, min_load_per_task = 0; | |
2265 | unsigned long min_nr_running = ULONG_MAX; | |
2266 | struct sched_group *group_min = NULL, *group_leader = NULL; | |
2267 | #endif | |
1da177e4 LT |
2268 | |
2269 | max_load = this_load = total_load = total_pwr = 0; | |
2dd73a4f PW |
2270 | busiest_load_per_task = busiest_nr_running = 0; |
2271 | this_load_per_task = this_nr_running = 0; | |
d15bcfdb | 2272 | if (idle == CPU_NOT_IDLE) |
7897986b | 2273 | load_idx = sd->busy_idx; |
d15bcfdb | 2274 | else if (idle == CPU_NEWLY_IDLE) |
7897986b NP |
2275 | load_idx = sd->newidle_idx; |
2276 | else | |
2277 | load_idx = sd->idle_idx; | |
1da177e4 LT |
2278 | |
2279 | do { | |
5c45bf27 | 2280 | unsigned long load, group_capacity; |
1da177e4 LT |
2281 | int local_group; |
2282 | int i; | |
783609c6 | 2283 | unsigned int balance_cpu = -1, first_idle_cpu = 0; |
2dd73a4f | 2284 | unsigned long sum_nr_running, sum_weighted_load; |
1da177e4 LT |
2285 | |
2286 | local_group = cpu_isset(this_cpu, group->cpumask); | |
2287 | ||
783609c6 SS |
2288 | if (local_group) |
2289 | balance_cpu = first_cpu(group->cpumask); | |
2290 | ||
1da177e4 | 2291 | /* Tally up the load of all CPUs in the group */ |
2dd73a4f | 2292 | sum_weighted_load = sum_nr_running = avg_load = 0; |
1da177e4 LT |
2293 | |
2294 | for_each_cpu_mask(i, group->cpumask) { | |
0a2966b4 CL |
2295 | struct rq *rq; |
2296 | ||
2297 | if (!cpu_isset(i, *cpus)) | |
2298 | continue; | |
2299 | ||
2300 | rq = cpu_rq(i); | |
2dd73a4f | 2301 | |
5969fe06 NP |
2302 | if (*sd_idle && !idle_cpu(i)) |
2303 | *sd_idle = 0; | |
2304 | ||
1da177e4 | 2305 | /* Bias balancing toward cpus of our domain */ |
783609c6 SS |
2306 | if (local_group) { |
2307 | if (idle_cpu(i) && !first_idle_cpu) { | |
2308 | first_idle_cpu = 1; | |
2309 | balance_cpu = i; | |
2310 | } | |
2311 | ||
a2000572 | 2312 | load = target_load(i, load_idx); |
783609c6 | 2313 | } else |
a2000572 | 2314 | load = source_load(i, load_idx); |
1da177e4 LT |
2315 | |
2316 | avg_load += load; | |
2dd73a4f | 2317 | sum_nr_running += rq->nr_running; |
dd41f596 | 2318 | sum_weighted_load += weighted_cpuload(i); |
1da177e4 LT |
2319 | } |
2320 | ||
783609c6 SS |
2321 | /* |
2322 | * First idle cpu or the first cpu(busiest) in this sched group | |
2323 | * is eligible for doing load balancing at this and above | |
2324 | * domains. | |
2325 | */ | |
2326 | if (local_group && balance_cpu != this_cpu && balance) { | |
2327 | *balance = 0; | |
2328 | goto ret; | |
2329 | } | |
2330 | ||
1da177e4 | 2331 | total_load += avg_load; |
5517d86b | 2332 | total_pwr += group->__cpu_power; |
1da177e4 LT |
2333 | |
2334 | /* Adjust by relative CPU power of the group */ | |
5517d86b ED |
2335 | avg_load = sg_div_cpu_power(group, |
2336 | avg_load * SCHED_LOAD_SCALE); | |
1da177e4 | 2337 | |
5517d86b | 2338 | group_capacity = group->__cpu_power / SCHED_LOAD_SCALE; |
5c45bf27 | 2339 | |
1da177e4 LT |
2340 | if (local_group) { |
2341 | this_load = avg_load; | |
2342 | this = group; | |
2dd73a4f PW |
2343 | this_nr_running = sum_nr_running; |
2344 | this_load_per_task = sum_weighted_load; | |
2345 | } else if (avg_load > max_load && | |
5c45bf27 | 2346 | sum_nr_running > group_capacity) { |
1da177e4 LT |
2347 | max_load = avg_load; |
2348 | busiest = group; | |
2dd73a4f PW |
2349 | busiest_nr_running = sum_nr_running; |
2350 | busiest_load_per_task = sum_weighted_load; | |
1da177e4 | 2351 | } |
5c45bf27 SS |
2352 | |
2353 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) | |
2354 | /* | |
2355 | * Busy processors will not participate in power savings | |
2356 | * balance. | |
2357 | */ | |
dd41f596 IM |
2358 | if (idle == CPU_NOT_IDLE || |
2359 | !(sd->flags & SD_POWERSAVINGS_BALANCE)) | |
2360 | goto group_next; | |
5c45bf27 SS |
2361 | |
2362 | /* | |
2363 | * If the local group is idle or completely loaded | |
2364 | * no need to do power savings balance at this domain | |
2365 | */ | |
2366 | if (local_group && (this_nr_running >= group_capacity || | |
2367 | !this_nr_running)) | |
2368 | power_savings_balance = 0; | |
2369 | ||
dd41f596 | 2370 | /* |
5c45bf27 SS |
2371 | * If a group is already running at full capacity or idle, |
2372 | * don't include that group in power savings calculations | |
dd41f596 IM |
2373 | */ |
2374 | if (!power_savings_balance || sum_nr_running >= group_capacity | |
5c45bf27 | 2375 | || !sum_nr_running) |
dd41f596 | 2376 | goto group_next; |
5c45bf27 | 2377 | |
dd41f596 | 2378 | /* |
5c45bf27 | 2379 | * Calculate the group which has the least non-idle load. |
dd41f596 IM |
2380 | * This is the group from where we need to pick up the load |
2381 | * for saving power | |
2382 | */ | |
2383 | if ((sum_nr_running < min_nr_running) || | |
2384 | (sum_nr_running == min_nr_running && | |
5c45bf27 SS |
2385 | first_cpu(group->cpumask) < |
2386 | first_cpu(group_min->cpumask))) { | |
dd41f596 IM |
2387 | group_min = group; |
2388 | min_nr_running = sum_nr_running; | |
5c45bf27 SS |
2389 | min_load_per_task = sum_weighted_load / |
2390 | sum_nr_running; | |
dd41f596 | 2391 | } |
5c45bf27 | 2392 | |
dd41f596 | 2393 | /* |
5c45bf27 | 2394 | * Calculate the group which is almost near its |
dd41f596 IM |
2395 | * capacity but still has some space to pick up some load |
2396 | * from other group and save more power | |
2397 | */ | |
2398 | if (sum_nr_running <= group_capacity - 1) { | |
2399 | if (sum_nr_running > leader_nr_running || | |
2400 | (sum_nr_running == leader_nr_running && | |
2401 | first_cpu(group->cpumask) > | |
2402 | first_cpu(group_leader->cpumask))) { | |
2403 | group_leader = group; | |
2404 | leader_nr_running = sum_nr_running; | |
2405 | } | |
48f24c4d | 2406 | } |
5c45bf27 SS |
2407 | group_next: |
2408 | #endif | |
1da177e4 LT |
2409 | group = group->next; |
2410 | } while (group != sd->groups); | |
2411 | ||
2dd73a4f | 2412 | if (!busiest || this_load >= max_load || busiest_nr_running == 0) |
1da177e4 LT |
2413 | goto out_balanced; |
2414 | ||
2415 | avg_load = (SCHED_LOAD_SCALE * total_load) / total_pwr; | |
2416 | ||
2417 | if (this_load >= avg_load || | |
2418 | 100*max_load <= sd->imbalance_pct*this_load) | |
2419 | goto out_balanced; | |
2420 | ||
2dd73a4f | 2421 | busiest_load_per_task /= busiest_nr_running; |
1da177e4 LT |
2422 | /* |
2423 | * We're trying to get all the cpus to the average_load, so we don't | |
2424 | * want to push ourselves above the average load, nor do we wish to | |
2425 | * reduce the max loaded cpu below the average load, as either of these | |
2426 | * actions would just result in more rebalancing later, and ping-pong | |
2427 | * tasks around. Thus we look for the minimum possible imbalance. | |
2428 | * Negative imbalances (*we* are more loaded than anyone else) will | |
2429 | * be counted as no imbalance for these purposes -- we can't fix that | |
2430 | * by pulling tasks to us. Be careful of negative numbers as they'll | |
2431 | * appear as very large values with unsigned longs. | |
2432 | */ | |
2dd73a4f PW |
2433 | if (max_load <= busiest_load_per_task) |
2434 | goto out_balanced; | |
2435 | ||
2436 | /* | |
2437 | * In the presence of smp nice balancing, certain scenarios can have | |
2438 | * max load less than avg load(as we skip the groups at or below | |
2439 | * its cpu_power, while calculating max_load..) | |
2440 | */ | |
2441 | if (max_load < avg_load) { | |
2442 | *imbalance = 0; | |
2443 | goto small_imbalance; | |
2444 | } | |
0c117f1b SS |
2445 | |
2446 | /* Don't want to pull so many tasks that a group would go idle */ | |
2dd73a4f | 2447 | max_pull = min(max_load - avg_load, max_load - busiest_load_per_task); |
0c117f1b | 2448 | |
1da177e4 | 2449 | /* How much load to actually move to equalise the imbalance */ |
5517d86b ED |
2450 | *imbalance = min(max_pull * busiest->__cpu_power, |
2451 | (avg_load - this_load) * this->__cpu_power) | |
1da177e4 LT |
2452 | / SCHED_LOAD_SCALE; |
2453 | ||
2dd73a4f PW |
2454 | /* |
2455 | * if *imbalance is less than the average load per runnable task | |
2456 | * there is no gaurantee that any tasks will be moved so we'll have | |
2457 | * a think about bumping its value to force at least one task to be | |
2458 | * moved | |
2459 | */ | |
dd41f596 | 2460 | if (*imbalance + SCHED_LOAD_SCALE_FUZZ < busiest_load_per_task/2) { |
48f24c4d | 2461 | unsigned long tmp, pwr_now, pwr_move; |
2dd73a4f PW |
2462 | unsigned int imbn; |
2463 | ||
2464 | small_imbalance: | |
2465 | pwr_move = pwr_now = 0; | |
2466 | imbn = 2; | |
2467 | if (this_nr_running) { | |
2468 | this_load_per_task /= this_nr_running; | |
2469 | if (busiest_load_per_task > this_load_per_task) | |
2470 | imbn = 1; | |
2471 | } else | |
2472 | this_load_per_task = SCHED_LOAD_SCALE; | |
1da177e4 | 2473 | |
dd41f596 IM |
2474 | if (max_load - this_load + SCHED_LOAD_SCALE_FUZZ >= |
2475 | busiest_load_per_task * imbn) { | |
2dd73a4f | 2476 | *imbalance = busiest_load_per_task; |
1da177e4 LT |
2477 | return busiest; |
2478 | } | |
2479 | ||
2480 | /* | |
2481 | * OK, we don't have enough imbalance to justify moving tasks, | |
2482 | * however we may be able to increase total CPU power used by | |
2483 | * moving them. | |
2484 | */ | |
2485 | ||
5517d86b ED |
2486 | pwr_now += busiest->__cpu_power * |
2487 | min(busiest_load_per_task, max_load); | |
2488 | pwr_now += this->__cpu_power * | |
2489 | min(this_load_per_task, this_load); | |
1da177e4 LT |
2490 | pwr_now /= SCHED_LOAD_SCALE; |
2491 | ||
2492 | /* Amount of load we'd subtract */ | |
5517d86b ED |
2493 | tmp = sg_div_cpu_power(busiest, |
2494 | busiest_load_per_task * SCHED_LOAD_SCALE); | |
1da177e4 | 2495 | if (max_load > tmp) |
5517d86b | 2496 | pwr_move += busiest->__cpu_power * |
2dd73a4f | 2497 | min(busiest_load_per_task, max_load - tmp); |
1da177e4 LT |
2498 | |
2499 | /* Amount of load we'd add */ | |
5517d86b | 2500 | if (max_load * busiest->__cpu_power < |
33859f7f | 2501 | busiest_load_per_task * SCHED_LOAD_SCALE) |
5517d86b ED |
2502 | tmp = sg_div_cpu_power(this, |
2503 | max_load * busiest->__cpu_power); | |
1da177e4 | 2504 | else |
5517d86b ED |
2505 | tmp = sg_div_cpu_power(this, |
2506 | busiest_load_per_task * SCHED_LOAD_SCALE); | |
2507 | pwr_move += this->__cpu_power * | |
2508 | min(this_load_per_task, this_load + tmp); | |
1da177e4 LT |
2509 | pwr_move /= SCHED_LOAD_SCALE; |
2510 | ||
2511 | /* Move if we gain throughput */ | |
2512 | if (pwr_move <= pwr_now) | |
2513 | goto out_balanced; | |
2514 | ||
2dd73a4f | 2515 | *imbalance = busiest_load_per_task; |
1da177e4 LT |
2516 | } |
2517 | ||
1da177e4 LT |
2518 | return busiest; |
2519 | ||
2520 | out_balanced: | |
5c45bf27 | 2521 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) |
d15bcfdb | 2522 | if (idle == CPU_NOT_IDLE || !(sd->flags & SD_POWERSAVINGS_BALANCE)) |
5c45bf27 | 2523 | goto ret; |
1da177e4 | 2524 | |
5c45bf27 SS |
2525 | if (this == group_leader && group_leader != group_min) { |
2526 | *imbalance = min_load_per_task; | |
2527 | return group_min; | |
2528 | } | |
5c45bf27 | 2529 | #endif |
783609c6 | 2530 | ret: |
1da177e4 LT |
2531 | *imbalance = 0; |
2532 | return NULL; | |
2533 | } | |
2534 | ||
2535 | /* | |
2536 | * find_busiest_queue - find the busiest runqueue among the cpus in group. | |
2537 | */ | |
70b97a7f | 2538 | static struct rq * |
d15bcfdb | 2539 | find_busiest_queue(struct sched_group *group, enum cpu_idle_type idle, |
0a2966b4 | 2540 | unsigned long imbalance, cpumask_t *cpus) |
1da177e4 | 2541 | { |
70b97a7f | 2542 | struct rq *busiest = NULL, *rq; |
2dd73a4f | 2543 | unsigned long max_load = 0; |
1da177e4 LT |
2544 | int i; |
2545 | ||
2546 | for_each_cpu_mask(i, group->cpumask) { | |
dd41f596 | 2547 | unsigned long wl; |
0a2966b4 CL |
2548 | |
2549 | if (!cpu_isset(i, *cpus)) | |
2550 | continue; | |
2551 | ||
48f24c4d | 2552 | rq = cpu_rq(i); |
dd41f596 | 2553 | wl = weighted_cpuload(i); |
2dd73a4f | 2554 | |
dd41f596 | 2555 | if (rq->nr_running == 1 && wl > imbalance) |
2dd73a4f | 2556 | continue; |
1da177e4 | 2557 | |
dd41f596 IM |
2558 | if (wl > max_load) { |
2559 | max_load = wl; | |
48f24c4d | 2560 | busiest = rq; |
1da177e4 LT |
2561 | } |
2562 | } | |
2563 | ||
2564 | return busiest; | |
2565 | } | |
2566 | ||
77391d71 NP |
2567 | /* |
2568 | * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but | |
2569 | * so long as it is large enough. | |
2570 | */ | |
2571 | #define MAX_PINNED_INTERVAL 512 | |
2572 | ||
48f24c4d IM |
2573 | static inline unsigned long minus_1_or_zero(unsigned long n) |
2574 | { | |
2575 | return n > 0 ? n - 1 : 0; | |
2576 | } | |
2577 | ||
1da177e4 LT |
2578 | /* |
2579 | * Check this_cpu to ensure it is balanced within domain. Attempt to move | |
2580 | * tasks if there is an imbalance. | |
1da177e4 | 2581 | */ |
70b97a7f | 2582 | static int load_balance(int this_cpu, struct rq *this_rq, |
d15bcfdb | 2583 | struct sched_domain *sd, enum cpu_idle_type idle, |
783609c6 | 2584 | int *balance) |
1da177e4 | 2585 | { |
48f24c4d | 2586 | int nr_moved, all_pinned = 0, active_balance = 0, sd_idle = 0; |
1da177e4 | 2587 | struct sched_group *group; |
1da177e4 | 2588 | unsigned long imbalance; |
70b97a7f | 2589 | struct rq *busiest; |
0a2966b4 | 2590 | cpumask_t cpus = CPU_MASK_ALL; |
fe2eea3f | 2591 | unsigned long flags; |
5969fe06 | 2592 | |
89c4710e SS |
2593 | /* |
2594 | * When power savings policy is enabled for the parent domain, idle | |
2595 | * sibling can pick up load irrespective of busy siblings. In this case, | |
dd41f596 | 2596 | * let the state of idle sibling percolate up as CPU_IDLE, instead of |
d15bcfdb | 2597 | * portraying it as CPU_NOT_IDLE. |
89c4710e | 2598 | */ |
d15bcfdb | 2599 | if (idle != CPU_NOT_IDLE && sd->flags & SD_SHARE_CPUPOWER && |
89c4710e | 2600 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
5969fe06 | 2601 | sd_idle = 1; |
1da177e4 | 2602 | |
1da177e4 LT |
2603 | schedstat_inc(sd, lb_cnt[idle]); |
2604 | ||
0a2966b4 CL |
2605 | redo: |
2606 | group = find_busiest_group(sd, this_cpu, &imbalance, idle, &sd_idle, | |
783609c6 SS |
2607 | &cpus, balance); |
2608 | ||
06066714 | 2609 | if (*balance == 0) |
783609c6 | 2610 | goto out_balanced; |
783609c6 | 2611 | |
1da177e4 LT |
2612 | if (!group) { |
2613 | schedstat_inc(sd, lb_nobusyg[idle]); | |
2614 | goto out_balanced; | |
2615 | } | |
2616 | ||
0a2966b4 | 2617 | busiest = find_busiest_queue(group, idle, imbalance, &cpus); |
1da177e4 LT |
2618 | if (!busiest) { |
2619 | schedstat_inc(sd, lb_nobusyq[idle]); | |
2620 | goto out_balanced; | |
2621 | } | |
2622 | ||
db935dbd | 2623 | BUG_ON(busiest == this_rq); |
1da177e4 LT |
2624 | |
2625 | schedstat_add(sd, lb_imbalance[idle], imbalance); | |
2626 | ||
2627 | nr_moved = 0; | |
2628 | if (busiest->nr_running > 1) { | |
2629 | /* | |
2630 | * Attempt to move tasks. If find_busiest_group has found | |
2631 | * an imbalance but busiest->nr_running <= 1, the group is | |
2632 | * still unbalanced. nr_moved simply stays zero, so it is | |
2633 | * correctly treated as an imbalance. | |
2634 | */ | |
fe2eea3f | 2635 | local_irq_save(flags); |
e17224bf | 2636 | double_rq_lock(this_rq, busiest); |
1da177e4 | 2637 | nr_moved = move_tasks(this_rq, this_cpu, busiest, |
48f24c4d IM |
2638 | minus_1_or_zero(busiest->nr_running), |
2639 | imbalance, sd, idle, &all_pinned); | |
e17224bf | 2640 | double_rq_unlock(this_rq, busiest); |
fe2eea3f | 2641 | local_irq_restore(flags); |
81026794 | 2642 | |
46cb4b7c SS |
2643 | /* |
2644 | * some other cpu did the load balance for us. | |
2645 | */ | |
2646 | if (nr_moved && this_cpu != smp_processor_id()) | |
2647 | resched_cpu(this_cpu); | |
2648 | ||
81026794 | 2649 | /* All tasks on this runqueue were pinned by CPU affinity */ |
0a2966b4 CL |
2650 | if (unlikely(all_pinned)) { |
2651 | cpu_clear(cpu_of(busiest), cpus); | |
2652 | if (!cpus_empty(cpus)) | |
2653 | goto redo; | |
81026794 | 2654 | goto out_balanced; |
0a2966b4 | 2655 | } |
1da177e4 | 2656 | } |
81026794 | 2657 | |
1da177e4 LT |
2658 | if (!nr_moved) { |
2659 | schedstat_inc(sd, lb_failed[idle]); | |
2660 | sd->nr_balance_failed++; | |
2661 | ||
2662 | if (unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2)) { | |
1da177e4 | 2663 | |
fe2eea3f | 2664 | spin_lock_irqsave(&busiest->lock, flags); |
fa3b6ddc SS |
2665 | |
2666 | /* don't kick the migration_thread, if the curr | |
2667 | * task on busiest cpu can't be moved to this_cpu | |
2668 | */ | |
2669 | if (!cpu_isset(this_cpu, busiest->curr->cpus_allowed)) { | |
fe2eea3f | 2670 | spin_unlock_irqrestore(&busiest->lock, flags); |
fa3b6ddc SS |
2671 | all_pinned = 1; |
2672 | goto out_one_pinned; | |
2673 | } | |
2674 | ||
1da177e4 LT |
2675 | if (!busiest->active_balance) { |
2676 | busiest->active_balance = 1; | |
2677 | busiest->push_cpu = this_cpu; | |
81026794 | 2678 | active_balance = 1; |
1da177e4 | 2679 | } |
fe2eea3f | 2680 | spin_unlock_irqrestore(&busiest->lock, flags); |
81026794 | 2681 | if (active_balance) |
1da177e4 LT |
2682 | wake_up_process(busiest->migration_thread); |
2683 | ||
2684 | /* | |
2685 | * We've kicked active balancing, reset the failure | |
2686 | * counter. | |
2687 | */ | |
39507451 | 2688 | sd->nr_balance_failed = sd->cache_nice_tries+1; |
1da177e4 | 2689 | } |
81026794 | 2690 | } else |
1da177e4 LT |
2691 | sd->nr_balance_failed = 0; |
2692 | ||
81026794 | 2693 | if (likely(!active_balance)) { |
1da177e4 LT |
2694 | /* We were unbalanced, so reset the balancing interval */ |
2695 | sd->balance_interval = sd->min_interval; | |
81026794 NP |
2696 | } else { |
2697 | /* | |
2698 | * If we've begun active balancing, start to back off. This | |
2699 | * case may not be covered by the all_pinned logic if there | |
2700 | * is only 1 task on the busy runqueue (because we don't call | |
2701 | * move_tasks). | |
2702 | */ | |
2703 | if (sd->balance_interval < sd->max_interval) | |
2704 | sd->balance_interval *= 2; | |
1da177e4 LT |
2705 | } |
2706 | ||
5c45bf27 | 2707 | if (!nr_moved && !sd_idle && sd->flags & SD_SHARE_CPUPOWER && |
89c4710e | 2708 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
5969fe06 | 2709 | return -1; |
1da177e4 LT |
2710 | return nr_moved; |
2711 | ||
2712 | out_balanced: | |
1da177e4 LT |
2713 | schedstat_inc(sd, lb_balanced[idle]); |
2714 | ||
16cfb1c0 | 2715 | sd->nr_balance_failed = 0; |
fa3b6ddc SS |
2716 | |
2717 | out_one_pinned: | |
1da177e4 | 2718 | /* tune up the balancing interval */ |
77391d71 NP |
2719 | if ((all_pinned && sd->balance_interval < MAX_PINNED_INTERVAL) || |
2720 | (sd->balance_interval < sd->max_interval)) | |
1da177e4 LT |
2721 | sd->balance_interval *= 2; |
2722 | ||
48f24c4d | 2723 | if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && |
89c4710e | 2724 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
5969fe06 | 2725 | return -1; |
1da177e4 LT |
2726 | return 0; |
2727 | } | |
2728 | ||
2729 | /* | |
2730 | * Check this_cpu to ensure it is balanced within domain. Attempt to move | |
2731 | * tasks if there is an imbalance. | |
2732 | * | |
d15bcfdb | 2733 | * Called from schedule when this_rq is about to become idle (CPU_NEWLY_IDLE). |
1da177e4 LT |
2734 | * this_rq is locked. |
2735 | */ | |
48f24c4d | 2736 | static int |
70b97a7f | 2737 | load_balance_newidle(int this_cpu, struct rq *this_rq, struct sched_domain *sd) |
1da177e4 LT |
2738 | { |
2739 | struct sched_group *group; | |
70b97a7f | 2740 | struct rq *busiest = NULL; |
1da177e4 LT |
2741 | unsigned long imbalance; |
2742 | int nr_moved = 0; | |
5969fe06 | 2743 | int sd_idle = 0; |
0a2966b4 | 2744 | cpumask_t cpus = CPU_MASK_ALL; |
5969fe06 | 2745 | |
89c4710e SS |
2746 | /* |
2747 | * When power savings policy is enabled for the parent domain, idle | |
2748 | * sibling can pick up load irrespective of busy siblings. In this case, | |
2749 | * let the state of idle sibling percolate up as IDLE, instead of | |
d15bcfdb | 2750 | * portraying it as CPU_NOT_IDLE. |
89c4710e SS |
2751 | */ |
2752 | if (sd->flags & SD_SHARE_CPUPOWER && | |
2753 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) | |
5969fe06 | 2754 | sd_idle = 1; |
1da177e4 | 2755 | |
d15bcfdb | 2756 | schedstat_inc(sd, lb_cnt[CPU_NEWLY_IDLE]); |
0a2966b4 | 2757 | redo: |
d15bcfdb | 2758 | group = find_busiest_group(sd, this_cpu, &imbalance, CPU_NEWLY_IDLE, |
783609c6 | 2759 | &sd_idle, &cpus, NULL); |
1da177e4 | 2760 | if (!group) { |
d15bcfdb | 2761 | schedstat_inc(sd, lb_nobusyg[CPU_NEWLY_IDLE]); |
16cfb1c0 | 2762 | goto out_balanced; |
1da177e4 LT |
2763 | } |
2764 | ||
d15bcfdb | 2765 | busiest = find_busiest_queue(group, CPU_NEWLY_IDLE, imbalance, |
0a2966b4 | 2766 | &cpus); |
db935dbd | 2767 | if (!busiest) { |
d15bcfdb | 2768 | schedstat_inc(sd, lb_nobusyq[CPU_NEWLY_IDLE]); |
16cfb1c0 | 2769 | goto out_balanced; |
1da177e4 LT |
2770 | } |
2771 | ||
db935dbd NP |
2772 | BUG_ON(busiest == this_rq); |
2773 | ||
d15bcfdb | 2774 | schedstat_add(sd, lb_imbalance[CPU_NEWLY_IDLE], imbalance); |
d6d5cfaf NP |
2775 | |
2776 | nr_moved = 0; | |
2777 | if (busiest->nr_running > 1) { | |
2778 | /* Attempt to move tasks */ | |
2779 | double_lock_balance(this_rq, busiest); | |
2780 | nr_moved = move_tasks(this_rq, this_cpu, busiest, | |
2dd73a4f | 2781 | minus_1_or_zero(busiest->nr_running), |
d15bcfdb | 2782 | imbalance, sd, CPU_NEWLY_IDLE, NULL); |
d6d5cfaf | 2783 | spin_unlock(&busiest->lock); |
0a2966b4 CL |
2784 | |
2785 | if (!nr_moved) { | |
2786 | cpu_clear(cpu_of(busiest), cpus); | |
2787 | if (!cpus_empty(cpus)) | |
2788 | goto redo; | |
2789 | } | |
d6d5cfaf NP |
2790 | } |
2791 | ||
5969fe06 | 2792 | if (!nr_moved) { |
d15bcfdb | 2793 | schedstat_inc(sd, lb_failed[CPU_NEWLY_IDLE]); |
89c4710e SS |
2794 | if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && |
2795 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) | |
5969fe06 NP |
2796 | return -1; |
2797 | } else | |
16cfb1c0 | 2798 | sd->nr_balance_failed = 0; |
1da177e4 | 2799 | |
1da177e4 | 2800 | return nr_moved; |
16cfb1c0 NP |
2801 | |
2802 | out_balanced: | |
d15bcfdb | 2803 | schedstat_inc(sd, lb_balanced[CPU_NEWLY_IDLE]); |
48f24c4d | 2804 | if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && |
89c4710e | 2805 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
5969fe06 | 2806 | return -1; |
16cfb1c0 | 2807 | sd->nr_balance_failed = 0; |
48f24c4d | 2808 | |
16cfb1c0 | 2809 | return 0; |
1da177e4 LT |
2810 | } |
2811 | ||
2812 | /* | |
2813 | * idle_balance is called by schedule() if this_cpu is about to become | |
2814 | * idle. Attempts to pull tasks from other CPUs. | |
2815 | */ | |
70b97a7f | 2816 | static void idle_balance(int this_cpu, struct rq *this_rq) |
1da177e4 LT |
2817 | { |
2818 | struct sched_domain *sd; | |
dd41f596 IM |
2819 | int pulled_task = -1; |
2820 | unsigned long next_balance = jiffies + HZ; | |
1da177e4 LT |
2821 | |
2822 | for_each_domain(this_cpu, sd) { | |
92c4ca5c CL |
2823 | unsigned long interval; |
2824 | ||
2825 | if (!(sd->flags & SD_LOAD_BALANCE)) | |
2826 | continue; | |
2827 | ||
2828 | if (sd->flags & SD_BALANCE_NEWIDLE) | |
48f24c4d | 2829 | /* If we've pulled tasks over stop searching: */ |
1bd77f2d | 2830 | pulled_task = load_balance_newidle(this_cpu, |
92c4ca5c CL |
2831 | this_rq, sd); |
2832 | ||
2833 | interval = msecs_to_jiffies(sd->balance_interval); | |
2834 | if (time_after(next_balance, sd->last_balance + interval)) | |
2835 | next_balance = sd->last_balance + interval; | |
2836 | if (pulled_task) | |
2837 | break; | |
1da177e4 | 2838 | } |
dd41f596 | 2839 | if (pulled_task || time_after(jiffies, this_rq->next_balance)) { |
1bd77f2d CL |
2840 | /* |
2841 | * We are going idle. next_balance may be set based on | |
2842 | * a busy processor. So reset next_balance. | |
2843 | */ | |
2844 | this_rq->next_balance = next_balance; | |
dd41f596 | 2845 | } |
1da177e4 LT |
2846 | } |
2847 | ||
2848 | /* | |
2849 | * active_load_balance is run by migration threads. It pushes running tasks | |
2850 | * off the busiest CPU onto idle CPUs. It requires at least 1 task to be | |
2851 | * running on each physical CPU where possible, and avoids physical / | |
2852 | * logical imbalances. | |
2853 | * | |
2854 | * Called with busiest_rq locked. | |
2855 | */ | |
70b97a7f | 2856 | static void active_load_balance(struct rq *busiest_rq, int busiest_cpu) |
1da177e4 | 2857 | { |
39507451 | 2858 | int target_cpu = busiest_rq->push_cpu; |
70b97a7f IM |
2859 | struct sched_domain *sd; |
2860 | struct rq *target_rq; | |
39507451 | 2861 | |
48f24c4d | 2862 | /* Is there any task to move? */ |
39507451 | 2863 | if (busiest_rq->nr_running <= 1) |
39507451 NP |
2864 | return; |
2865 | ||
2866 | target_rq = cpu_rq(target_cpu); | |
1da177e4 LT |
2867 | |
2868 | /* | |
39507451 NP |
2869 | * This condition is "impossible", if it occurs |
2870 | * we need to fix it. Originally reported by | |
2871 | * Bjorn Helgaas on a 128-cpu setup. | |
1da177e4 | 2872 | */ |
39507451 | 2873 | BUG_ON(busiest_rq == target_rq); |
1da177e4 | 2874 | |
39507451 NP |
2875 | /* move a task from busiest_rq to target_rq */ |
2876 | double_lock_balance(busiest_rq, target_rq); | |
2877 | ||
2878 | /* Search for an sd spanning us and the target CPU. */ | |
c96d145e | 2879 | for_each_domain(target_cpu, sd) { |
39507451 | 2880 | if ((sd->flags & SD_LOAD_BALANCE) && |
48f24c4d | 2881 | cpu_isset(busiest_cpu, sd->span)) |
39507451 | 2882 | break; |
c96d145e | 2883 | } |
39507451 | 2884 | |
48f24c4d IM |
2885 | if (likely(sd)) { |
2886 | schedstat_inc(sd, alb_cnt); | |
39507451 | 2887 | |
48f24c4d | 2888 | if (move_tasks(target_rq, target_cpu, busiest_rq, 1, |
d15bcfdb | 2889 | RTPRIO_TO_LOAD_WEIGHT(100), sd, CPU_IDLE, |
48f24c4d IM |
2890 | NULL)) |
2891 | schedstat_inc(sd, alb_pushed); | |
2892 | else | |
2893 | schedstat_inc(sd, alb_failed); | |
2894 | } | |
39507451 | 2895 | spin_unlock(&target_rq->lock); |
1da177e4 LT |
2896 | } |
2897 | ||
46cb4b7c SS |
2898 | #ifdef CONFIG_NO_HZ |
2899 | static struct { | |
2900 | atomic_t load_balancer; | |
2901 | cpumask_t cpu_mask; | |
2902 | } nohz ____cacheline_aligned = { | |
2903 | .load_balancer = ATOMIC_INIT(-1), | |
2904 | .cpu_mask = CPU_MASK_NONE, | |
2905 | }; | |
2906 | ||
7835b98b | 2907 | /* |
46cb4b7c SS |
2908 | * This routine will try to nominate the ilb (idle load balancing) |
2909 | * owner among the cpus whose ticks are stopped. ilb owner will do the idle | |
2910 | * load balancing on behalf of all those cpus. If all the cpus in the system | |
2911 | * go into this tickless mode, then there will be no ilb owner (as there is | |
2912 | * no need for one) and all the cpus will sleep till the next wakeup event | |
2913 | * arrives... | |
2914 | * | |
2915 | * For the ilb owner, tick is not stopped. And this tick will be used | |
2916 | * for idle load balancing. ilb owner will still be part of | |
2917 | * nohz.cpu_mask.. | |
7835b98b | 2918 | * |
46cb4b7c SS |
2919 | * While stopping the tick, this cpu will become the ilb owner if there |
2920 | * is no other owner. And will be the owner till that cpu becomes busy | |
2921 | * or if all cpus in the system stop their ticks at which point | |
2922 | * there is no need for ilb owner. | |
2923 | * | |
2924 | * When the ilb owner becomes busy, it nominates another owner, during the | |
2925 | * next busy scheduler_tick() | |
2926 | */ | |
2927 | int select_nohz_load_balancer(int stop_tick) | |
2928 | { | |
2929 | int cpu = smp_processor_id(); | |
2930 | ||
2931 | if (stop_tick) { | |
2932 | cpu_set(cpu, nohz.cpu_mask); | |
2933 | cpu_rq(cpu)->in_nohz_recently = 1; | |
2934 | ||
2935 | /* | |
2936 | * If we are going offline and still the leader, give up! | |
2937 | */ | |
2938 | if (cpu_is_offline(cpu) && | |
2939 | atomic_read(&nohz.load_balancer) == cpu) { | |
2940 | if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu) | |
2941 | BUG(); | |
2942 | return 0; | |
2943 | } | |
2944 | ||
2945 | /* time for ilb owner also to sleep */ | |
2946 | if (cpus_weight(nohz.cpu_mask) == num_online_cpus()) { | |
2947 | if (atomic_read(&nohz.load_balancer) == cpu) | |
2948 | atomic_set(&nohz.load_balancer, -1); | |
2949 | return 0; | |
2950 | } | |
2951 | ||
2952 | if (atomic_read(&nohz.load_balancer) == -1) { | |
2953 | /* make me the ilb owner */ | |
2954 | if (atomic_cmpxchg(&nohz.load_balancer, -1, cpu) == -1) | |
2955 | return 1; | |
2956 | } else if (atomic_read(&nohz.load_balancer) == cpu) | |
2957 | return 1; | |
2958 | } else { | |
2959 | if (!cpu_isset(cpu, nohz.cpu_mask)) | |
2960 | return 0; | |
2961 | ||
2962 | cpu_clear(cpu, nohz.cpu_mask); | |
2963 | ||
2964 | if (atomic_read(&nohz.load_balancer) == cpu) | |
2965 | if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu) | |
2966 | BUG(); | |
2967 | } | |
2968 | return 0; | |
2969 | } | |
2970 | #endif | |
2971 | ||
2972 | static DEFINE_SPINLOCK(balancing); | |
2973 | ||
2974 | /* | |
7835b98b CL |
2975 | * It checks each scheduling domain to see if it is due to be balanced, |
2976 | * and initiates a balancing operation if so. | |
2977 | * | |
2978 | * Balancing parameters are set up in arch_init_sched_domains. | |
2979 | */ | |
d15bcfdb | 2980 | static inline void rebalance_domains(int cpu, enum cpu_idle_type idle) |
7835b98b | 2981 | { |
46cb4b7c SS |
2982 | int balance = 1; |
2983 | struct rq *rq = cpu_rq(cpu); | |
7835b98b CL |
2984 | unsigned long interval; |
2985 | struct sched_domain *sd; | |
46cb4b7c | 2986 | /* Earliest time when we have to do rebalance again */ |
c9819f45 | 2987 | unsigned long next_balance = jiffies + 60*HZ; |
1da177e4 | 2988 | |
46cb4b7c | 2989 | for_each_domain(cpu, sd) { |
1da177e4 LT |
2990 | if (!(sd->flags & SD_LOAD_BALANCE)) |
2991 | continue; | |
2992 | ||
2993 | interval = sd->balance_interval; | |
d15bcfdb | 2994 | if (idle != CPU_IDLE) |
1da177e4 LT |
2995 | interval *= sd->busy_factor; |
2996 | ||
2997 | /* scale ms to jiffies */ | |
2998 | interval = msecs_to_jiffies(interval); | |
2999 | if (unlikely(!interval)) | |
3000 | interval = 1; | |
dd41f596 IM |
3001 | if (interval > HZ*NR_CPUS/10) |
3002 | interval = HZ*NR_CPUS/10; | |
3003 | ||
1da177e4 | 3004 | |
08c183f3 CL |
3005 | if (sd->flags & SD_SERIALIZE) { |
3006 | if (!spin_trylock(&balancing)) | |
3007 | goto out; | |
3008 | } | |
3009 | ||
c9819f45 | 3010 | if (time_after_eq(jiffies, sd->last_balance + interval)) { |
46cb4b7c | 3011 | if (load_balance(cpu, rq, sd, idle, &balance)) { |
fa3b6ddc SS |
3012 | /* |
3013 | * We've pulled tasks over so either we're no | |
5969fe06 NP |
3014 | * longer idle, or one of our SMT siblings is |
3015 | * not idle. | |
3016 | */ | |
d15bcfdb | 3017 | idle = CPU_NOT_IDLE; |
1da177e4 | 3018 | } |
1bd77f2d | 3019 | sd->last_balance = jiffies; |
1da177e4 | 3020 | } |
08c183f3 CL |
3021 | if (sd->flags & SD_SERIALIZE) |
3022 | spin_unlock(&balancing); | |
3023 | out: | |
c9819f45 CL |
3024 | if (time_after(next_balance, sd->last_balance + interval)) |
3025 | next_balance = sd->last_balance + interval; | |
783609c6 SS |
3026 | |
3027 | /* | |
3028 | * Stop the load balance at this level. There is another | |
3029 | * CPU in our sched group which is doing load balancing more | |
3030 | * actively. | |
3031 | */ | |
3032 | if (!balance) | |
3033 | break; | |
1da177e4 | 3034 | } |
46cb4b7c SS |
3035 | rq->next_balance = next_balance; |
3036 | } | |
3037 | ||
3038 | /* | |
3039 | * run_rebalance_domains is triggered when needed from the scheduler tick. | |
3040 | * In CONFIG_NO_HZ case, the idle load balance owner will do the | |
3041 | * rebalancing for all the cpus for whom scheduler ticks are stopped. | |
3042 | */ | |
3043 | static void run_rebalance_domains(struct softirq_action *h) | |
3044 | { | |
dd41f596 IM |
3045 | int this_cpu = smp_processor_id(); |
3046 | struct rq *this_rq = cpu_rq(this_cpu); | |
3047 | enum cpu_idle_type idle = this_rq->idle_at_tick ? | |
3048 | CPU_IDLE : CPU_NOT_IDLE; | |
46cb4b7c | 3049 | |
dd41f596 | 3050 | rebalance_domains(this_cpu, idle); |
46cb4b7c SS |
3051 | |
3052 | #ifdef CONFIG_NO_HZ | |
3053 | /* | |
3054 | * If this cpu is the owner for idle load balancing, then do the | |
3055 | * balancing on behalf of the other idle cpus whose ticks are | |
3056 | * stopped. | |
3057 | */ | |
dd41f596 IM |
3058 | if (this_rq->idle_at_tick && |
3059 | atomic_read(&nohz.load_balancer) == this_cpu) { | |
46cb4b7c SS |
3060 | cpumask_t cpus = nohz.cpu_mask; |
3061 | struct rq *rq; | |
3062 | int balance_cpu; | |
3063 | ||
dd41f596 | 3064 | cpu_clear(this_cpu, cpus); |
46cb4b7c SS |
3065 | for_each_cpu_mask(balance_cpu, cpus) { |
3066 | /* | |
3067 | * If this cpu gets work to do, stop the load balancing | |
3068 | * work being done for other cpus. Next load | |
3069 | * balancing owner will pick it up. | |
3070 | */ | |
3071 | if (need_resched()) | |
3072 | break; | |
3073 | ||
dd41f596 | 3074 | rebalance_domains(balance_cpu, SCHED_IDLE); |
46cb4b7c SS |
3075 | |
3076 | rq = cpu_rq(balance_cpu); | |
dd41f596 IM |
3077 | if (time_after(this_rq->next_balance, rq->next_balance)) |
3078 | this_rq->next_balance = rq->next_balance; | |
46cb4b7c SS |
3079 | } |
3080 | } | |
3081 | #endif | |
3082 | } | |
3083 | ||
3084 | /* | |
3085 | * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing. | |
3086 | * | |
3087 | * In case of CONFIG_NO_HZ, this is the place where we nominate a new | |
3088 | * idle load balancing owner or decide to stop the periodic load balancing, | |
3089 | * if the whole system is idle. | |
3090 | */ | |
dd41f596 | 3091 | static inline void trigger_load_balance(struct rq *rq, int cpu) |
46cb4b7c | 3092 | { |
46cb4b7c SS |
3093 | #ifdef CONFIG_NO_HZ |
3094 | /* | |
3095 | * If we were in the nohz mode recently and busy at the current | |
3096 | * scheduler tick, then check if we need to nominate new idle | |
3097 | * load balancer. | |
3098 | */ | |
3099 | if (rq->in_nohz_recently && !rq->idle_at_tick) { | |
3100 | rq->in_nohz_recently = 0; | |
3101 | ||
3102 | if (atomic_read(&nohz.load_balancer) == cpu) { | |
3103 | cpu_clear(cpu, nohz.cpu_mask); | |
3104 | atomic_set(&nohz.load_balancer, -1); | |
3105 | } | |
3106 | ||
3107 | if (atomic_read(&nohz.load_balancer) == -1) { | |
3108 | /* | |
3109 | * simple selection for now: Nominate the | |
3110 | * first cpu in the nohz list to be the next | |
3111 | * ilb owner. | |
3112 | * | |
3113 | * TBD: Traverse the sched domains and nominate | |
3114 | * the nearest cpu in the nohz.cpu_mask. | |
3115 | */ | |
3116 | int ilb = first_cpu(nohz.cpu_mask); | |
3117 | ||
3118 | if (ilb != NR_CPUS) | |
3119 | resched_cpu(ilb); | |
3120 | } | |
3121 | } | |
3122 | ||
3123 | /* | |
3124 | * If this cpu is idle and doing idle load balancing for all the | |
3125 | * cpus with ticks stopped, is it time for that to stop? | |
3126 | */ | |
3127 | if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) == cpu && | |
3128 | cpus_weight(nohz.cpu_mask) == num_online_cpus()) { | |
3129 | resched_cpu(cpu); | |
3130 | return; | |
3131 | } | |
3132 | ||
3133 | /* | |
3134 | * If this cpu is idle and the idle load balancing is done by | |
3135 | * someone else, then no need raise the SCHED_SOFTIRQ | |
3136 | */ | |
3137 | if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) != cpu && | |
3138 | cpu_isset(cpu, nohz.cpu_mask)) | |
3139 | return; | |
3140 | #endif | |
3141 | if (time_after_eq(jiffies, rq->next_balance)) | |
3142 | raise_softirq(SCHED_SOFTIRQ); | |
1da177e4 | 3143 | } |
dd41f596 IM |
3144 | |
3145 | #else /* CONFIG_SMP */ | |
3146 | ||
1da177e4 LT |
3147 | /* |
3148 | * on UP we do not need to balance between CPUs: | |
3149 | */ | |
70b97a7f | 3150 | static inline void idle_balance(int cpu, struct rq *rq) |
1da177e4 LT |
3151 | { |
3152 | } | |
dd41f596 IM |
3153 | |
3154 | /* Avoid "used but not defined" warning on UP */ | |
3155 | static int balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
3156 | unsigned long max_nr_move, unsigned long max_load_move, | |
3157 | struct sched_domain *sd, enum cpu_idle_type idle, | |
3158 | int *all_pinned, unsigned long *load_moved, | |
3159 | int this_best_prio, int best_prio, int best_prio_seen, | |
3160 | struct rq_iterator *iterator) | |
3161 | { | |
3162 | *load_moved = 0; | |
3163 | ||
3164 | return 0; | |
3165 | } | |
3166 | ||
1da177e4 LT |
3167 | #endif |
3168 | ||
1da177e4 LT |
3169 | DEFINE_PER_CPU(struct kernel_stat, kstat); |
3170 | ||
3171 | EXPORT_PER_CPU_SYMBOL(kstat); | |
3172 | ||
3173 | /* | |
41b86e9c IM |
3174 | * Return p->sum_exec_runtime plus any more ns on the sched_clock |
3175 | * that have not yet been banked in case the task is currently running. | |
1da177e4 | 3176 | */ |
41b86e9c | 3177 | unsigned long long task_sched_runtime(struct task_struct *p) |
1da177e4 | 3178 | { |
1da177e4 | 3179 | unsigned long flags; |
41b86e9c IM |
3180 | u64 ns, delta_exec; |
3181 | struct rq *rq; | |
48f24c4d | 3182 | |
41b86e9c IM |
3183 | rq = task_rq_lock(p, &flags); |
3184 | ns = p->se.sum_exec_runtime; | |
3185 | if (rq->curr == p) { | |
3186 | delta_exec = rq_clock(rq) - p->se.exec_start; | |
3187 | if ((s64)delta_exec > 0) | |
3188 | ns += delta_exec; | |
3189 | } | |
3190 | task_rq_unlock(rq, &flags); | |
48f24c4d | 3191 | |
1da177e4 LT |
3192 | return ns; |
3193 | } | |
3194 | ||
1da177e4 LT |
3195 | /* |
3196 | * Account user cpu time to a process. | |
3197 | * @p: the process that the cpu time gets accounted to | |
3198 | * @hardirq_offset: the offset to subtract from hardirq_count() | |
3199 | * @cputime: the cpu time spent in user space since the last update | |
3200 | */ | |
3201 | void account_user_time(struct task_struct *p, cputime_t cputime) | |
3202 | { | |
3203 | struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; | |
3204 | cputime64_t tmp; | |
3205 | ||
3206 | p->utime = cputime_add(p->utime, cputime); | |
3207 | ||
3208 | /* Add user time to cpustat. */ | |
3209 | tmp = cputime_to_cputime64(cputime); | |
3210 | if (TASK_NICE(p) > 0) | |
3211 | cpustat->nice = cputime64_add(cpustat->nice, tmp); | |
3212 | else | |
3213 | cpustat->user = cputime64_add(cpustat->user, tmp); | |
3214 | } | |
3215 | ||
3216 | /* | |
3217 | * Account system cpu time to a process. | |
3218 | * @p: the process that the cpu time gets accounted to | |
3219 | * @hardirq_offset: the offset to subtract from hardirq_count() | |
3220 | * @cputime: the cpu time spent in kernel space since the last update | |
3221 | */ | |
3222 | void account_system_time(struct task_struct *p, int hardirq_offset, | |
3223 | cputime_t cputime) | |
3224 | { | |
3225 | struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; | |
70b97a7f | 3226 | struct rq *rq = this_rq(); |
1da177e4 LT |
3227 | cputime64_t tmp; |
3228 | ||
3229 | p->stime = cputime_add(p->stime, cputime); | |
3230 | ||
3231 | /* Add system time to cpustat. */ | |
3232 | tmp = cputime_to_cputime64(cputime); | |
3233 | if (hardirq_count() - hardirq_offset) | |
3234 | cpustat->irq = cputime64_add(cpustat->irq, tmp); | |
3235 | else if (softirq_count()) | |
3236 | cpustat->softirq = cputime64_add(cpustat->softirq, tmp); | |
3237 | else if (p != rq->idle) | |
3238 | cpustat->system = cputime64_add(cpustat->system, tmp); | |
3239 | else if (atomic_read(&rq->nr_iowait) > 0) | |
3240 | cpustat->iowait = cputime64_add(cpustat->iowait, tmp); | |
3241 | else | |
3242 | cpustat->idle = cputime64_add(cpustat->idle, tmp); | |
3243 | /* Account for system time used */ | |
3244 | acct_update_integrals(p); | |
1da177e4 LT |
3245 | } |
3246 | ||
3247 | /* | |
3248 | * Account for involuntary wait time. | |
3249 | * @p: the process from which the cpu time has been stolen | |
3250 | * @steal: the cpu time spent in involuntary wait | |
3251 | */ | |
3252 | void account_steal_time(struct task_struct *p, cputime_t steal) | |
3253 | { | |
3254 | struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; | |
3255 | cputime64_t tmp = cputime_to_cputime64(steal); | |
70b97a7f | 3256 | struct rq *rq = this_rq(); |
1da177e4 LT |
3257 | |
3258 | if (p == rq->idle) { | |
3259 | p->stime = cputime_add(p->stime, steal); | |
3260 | if (atomic_read(&rq->nr_iowait) > 0) | |
3261 | cpustat->iowait = cputime64_add(cpustat->iowait, tmp); | |
3262 | else | |
3263 | cpustat->idle = cputime64_add(cpustat->idle, tmp); | |
3264 | } else | |
3265 | cpustat->steal = cputime64_add(cpustat->steal, tmp); | |
3266 | } | |
3267 | ||
7835b98b CL |
3268 | /* |
3269 | * This function gets called by the timer code, with HZ frequency. | |
3270 | * We call it with interrupts disabled. | |
3271 | * | |
3272 | * It also gets called by the fork code, when changing the parent's | |
3273 | * timeslices. | |
3274 | */ | |
3275 | void scheduler_tick(void) | |
3276 | { | |
7835b98b CL |
3277 | int cpu = smp_processor_id(); |
3278 | struct rq *rq = cpu_rq(cpu); | |
dd41f596 IM |
3279 | struct task_struct *curr = rq->curr; |
3280 | ||
3281 | spin_lock(&rq->lock); | |
3282 | if (curr != rq->idle) /* FIXME: needed? */ | |
3283 | curr->sched_class->task_tick(rq, curr); | |
3284 | update_cpu_load(rq); | |
3285 | spin_unlock(&rq->lock); | |
7835b98b | 3286 | |
e418e1c2 | 3287 | #ifdef CONFIG_SMP |
dd41f596 IM |
3288 | rq->idle_at_tick = idle_cpu(cpu); |
3289 | trigger_load_balance(rq, cpu); | |
e418e1c2 | 3290 | #endif |
1da177e4 LT |
3291 | } |
3292 | ||
1da177e4 LT |
3293 | #if defined(CONFIG_PREEMPT) && defined(CONFIG_DEBUG_PREEMPT) |
3294 | ||
3295 | void fastcall add_preempt_count(int val) | |
3296 | { | |
3297 | /* | |
3298 | * Underflow? | |
3299 | */ | |
9a11b49a IM |
3300 | if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0))) |
3301 | return; | |
1da177e4 LT |
3302 | preempt_count() += val; |
3303 | /* | |
3304 | * Spinlock count overflowing soon? | |
3305 | */ | |
33859f7f MOS |
3306 | DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >= |
3307 | PREEMPT_MASK - 10); | |
1da177e4 LT |
3308 | } |
3309 | EXPORT_SYMBOL(add_preempt_count); | |
3310 | ||
3311 | void fastcall sub_preempt_count(int val) | |
3312 | { | |
3313 | /* | |
3314 | * Underflow? | |
3315 | */ | |
9a11b49a IM |
3316 | if (DEBUG_LOCKS_WARN_ON(val > preempt_count())) |
3317 | return; | |
1da177e4 LT |
3318 | /* |
3319 | * Is the spinlock portion underflowing? | |
3320 | */ | |
9a11b49a IM |
3321 | if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) && |
3322 | !(preempt_count() & PREEMPT_MASK))) | |
3323 | return; | |
3324 | ||
1da177e4 LT |
3325 | preempt_count() -= val; |
3326 | } | |
3327 | EXPORT_SYMBOL(sub_preempt_count); | |
3328 | ||
3329 | #endif | |
3330 | ||
3331 | /* | |
dd41f596 | 3332 | * Print scheduling while atomic bug: |
1da177e4 | 3333 | */ |
dd41f596 | 3334 | static noinline void __schedule_bug(struct task_struct *prev) |
1da177e4 | 3335 | { |
dd41f596 IM |
3336 | printk(KERN_ERR "BUG: scheduling while atomic: %s/0x%08x/%d\n", |
3337 | prev->comm, preempt_count(), prev->pid); | |
3338 | debug_show_held_locks(prev); | |
3339 | if (irqs_disabled()) | |
3340 | print_irqtrace_events(prev); | |
3341 | dump_stack(); | |
3342 | } | |
1da177e4 | 3343 | |
dd41f596 IM |
3344 | /* |
3345 | * Various schedule()-time debugging checks and statistics: | |
3346 | */ | |
3347 | static inline void schedule_debug(struct task_struct *prev) | |
3348 | { | |
1da177e4 LT |
3349 | /* |
3350 | * Test if we are atomic. Since do_exit() needs to call into | |
3351 | * schedule() atomically, we ignore that path for now. | |
3352 | * Otherwise, whine if we are scheduling when we should not be. | |
3353 | */ | |
dd41f596 IM |
3354 | if (unlikely(in_atomic_preempt_off()) && unlikely(!prev->exit_state)) |
3355 | __schedule_bug(prev); | |
3356 | ||
1da177e4 LT |
3357 | profile_hit(SCHED_PROFILING, __builtin_return_address(0)); |
3358 | ||
dd41f596 IM |
3359 | schedstat_inc(this_rq(), sched_cnt); |
3360 | } | |
3361 | ||
3362 | /* | |
3363 | * Pick up the highest-prio task: | |
3364 | */ | |
3365 | static inline struct task_struct * | |
3366 | pick_next_task(struct rq *rq, struct task_struct *prev, u64 now) | |
3367 | { | |
3368 | struct sched_class *class; | |
3369 | struct task_struct *p; | |
1da177e4 LT |
3370 | |
3371 | /* | |
dd41f596 IM |
3372 | * Optimization: we know that if all tasks are in |
3373 | * the fair class we can call that function directly: | |
1da177e4 | 3374 | */ |
dd41f596 IM |
3375 | if (likely(rq->nr_running == rq->cfs.nr_running)) { |
3376 | p = fair_sched_class.pick_next_task(rq, now); | |
3377 | if (likely(p)) | |
3378 | return p; | |
1da177e4 LT |
3379 | } |
3380 | ||
dd41f596 IM |
3381 | class = sched_class_highest; |
3382 | for ( ; ; ) { | |
3383 | p = class->pick_next_task(rq, now); | |
3384 | if (p) | |
3385 | return p; | |
3386 | /* | |
3387 | * Will never be NULL as the idle class always | |
3388 | * returns a non-NULL p: | |
3389 | */ | |
3390 | class = class->next; | |
3391 | } | |
3392 | } | |
1da177e4 | 3393 | |
dd41f596 IM |
3394 | /* |
3395 | * schedule() is the main scheduler function. | |
3396 | */ | |
3397 | asmlinkage void __sched schedule(void) | |
3398 | { | |
3399 | struct task_struct *prev, *next; | |
3400 | long *switch_count; | |
3401 | struct rq *rq; | |
3402 | u64 now; | |
3403 | int cpu; | |
3404 | ||
3405 | need_resched: | |
3406 | preempt_disable(); | |
3407 | cpu = smp_processor_id(); | |
3408 | rq = cpu_rq(cpu); | |
3409 | rcu_qsctr_inc(cpu); | |
3410 | prev = rq->curr; | |
3411 | switch_count = &prev->nivcsw; | |
3412 | ||
3413 | release_kernel_lock(prev); | |
3414 | need_resched_nonpreemptible: | |
3415 | ||
3416 | schedule_debug(prev); | |
1da177e4 LT |
3417 | |
3418 | spin_lock_irq(&rq->lock); | |
dd41f596 | 3419 | clear_tsk_need_resched(prev); |
1da177e4 | 3420 | |
1da177e4 | 3421 | if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) { |
1da177e4 | 3422 | if (unlikely((prev->state & TASK_INTERRUPTIBLE) && |
dd41f596 | 3423 | unlikely(signal_pending(prev)))) { |
1da177e4 | 3424 | prev->state = TASK_RUNNING; |
dd41f596 IM |
3425 | } else { |
3426 | deactivate_task(rq, prev, 1); | |
1da177e4 | 3427 | } |
dd41f596 | 3428 | switch_count = &prev->nvcsw; |
1da177e4 LT |
3429 | } |
3430 | ||
dd41f596 | 3431 | if (unlikely(!rq->nr_running)) |
1da177e4 | 3432 | idle_balance(cpu, rq); |
1da177e4 | 3433 | |
dd41f596 IM |
3434 | now = __rq_clock(rq); |
3435 | prev->sched_class->put_prev_task(rq, prev, now); | |
3436 | next = pick_next_task(rq, prev, now); | |
1da177e4 LT |
3437 | |
3438 | sched_info_switch(prev, next); | |
dd41f596 | 3439 | |
1da177e4 | 3440 | if (likely(prev != next)) { |
1da177e4 LT |
3441 | rq->nr_switches++; |
3442 | rq->curr = next; | |
3443 | ++*switch_count; | |
3444 | ||
dd41f596 | 3445 | context_switch(rq, prev, next); /* unlocks the rq */ |
1da177e4 LT |
3446 | } else |
3447 | spin_unlock_irq(&rq->lock); | |
3448 | ||
dd41f596 IM |
3449 | if (unlikely(reacquire_kernel_lock(current) < 0)) { |
3450 | cpu = smp_processor_id(); | |
3451 | rq = cpu_rq(cpu); | |
1da177e4 | 3452 | goto need_resched_nonpreemptible; |
dd41f596 | 3453 | } |
1da177e4 LT |
3454 | preempt_enable_no_resched(); |
3455 | if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) | |
3456 | goto need_resched; | |
3457 | } | |
1da177e4 LT |
3458 | EXPORT_SYMBOL(schedule); |
3459 | ||
3460 | #ifdef CONFIG_PREEMPT | |
3461 | /* | |
2ed6e34f | 3462 | * this is the entry point to schedule() from in-kernel preemption |
1da177e4 LT |
3463 | * off of preempt_enable. Kernel preemptions off return from interrupt |
3464 | * occur there and call schedule directly. | |
3465 | */ | |
3466 | asmlinkage void __sched preempt_schedule(void) | |
3467 | { | |
3468 | struct thread_info *ti = current_thread_info(); | |
3469 | #ifdef CONFIG_PREEMPT_BKL | |
3470 | struct task_struct *task = current; | |
3471 | int saved_lock_depth; | |
3472 | #endif | |
3473 | /* | |
3474 | * If there is a non-zero preempt_count or interrupts are disabled, | |
3475 | * we do not want to preempt the current task. Just return.. | |
3476 | */ | |
beed33a8 | 3477 | if (likely(ti->preempt_count || irqs_disabled())) |
1da177e4 LT |
3478 | return; |
3479 | ||
3480 | need_resched: | |
3481 | add_preempt_count(PREEMPT_ACTIVE); | |
3482 | /* | |
3483 | * We keep the big kernel semaphore locked, but we | |
3484 | * clear ->lock_depth so that schedule() doesnt | |
3485 | * auto-release the semaphore: | |
3486 | */ | |
3487 | #ifdef CONFIG_PREEMPT_BKL | |
3488 | saved_lock_depth = task->lock_depth; | |
3489 | task->lock_depth = -1; | |
3490 | #endif | |
3491 | schedule(); | |
3492 | #ifdef CONFIG_PREEMPT_BKL | |
3493 | task->lock_depth = saved_lock_depth; | |
3494 | #endif | |
3495 | sub_preempt_count(PREEMPT_ACTIVE); | |
3496 | ||
3497 | /* we could miss a preemption opportunity between schedule and now */ | |
3498 | barrier(); | |
3499 | if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) | |
3500 | goto need_resched; | |
3501 | } | |
1da177e4 LT |
3502 | EXPORT_SYMBOL(preempt_schedule); |
3503 | ||
3504 | /* | |
2ed6e34f | 3505 | * this is the entry point to schedule() from kernel preemption |
1da177e4 LT |
3506 | * off of irq context. |
3507 | * Note, that this is called and return with irqs disabled. This will | |
3508 | * protect us against recursive calling from irq. | |
3509 | */ | |
3510 | asmlinkage void __sched preempt_schedule_irq(void) | |
3511 | { | |
3512 | struct thread_info *ti = current_thread_info(); | |
3513 | #ifdef CONFIG_PREEMPT_BKL | |
3514 | struct task_struct *task = current; | |
3515 | int saved_lock_depth; | |
3516 | #endif | |
2ed6e34f | 3517 | /* Catch callers which need to be fixed */ |
1da177e4 LT |
3518 | BUG_ON(ti->preempt_count || !irqs_disabled()); |
3519 | ||
3520 | need_resched: | |
3521 | add_preempt_count(PREEMPT_ACTIVE); | |
3522 | /* | |
3523 | * We keep the big kernel semaphore locked, but we | |
3524 | * clear ->lock_depth so that schedule() doesnt | |
3525 | * auto-release the semaphore: | |
3526 | */ | |
3527 | #ifdef CONFIG_PREEMPT_BKL | |
3528 | saved_lock_depth = task->lock_depth; | |
3529 | task->lock_depth = -1; | |
3530 | #endif | |
3531 | local_irq_enable(); | |
3532 | schedule(); | |
3533 | local_irq_disable(); | |
3534 | #ifdef CONFIG_PREEMPT_BKL | |
3535 | task->lock_depth = saved_lock_depth; | |
3536 | #endif | |
3537 | sub_preempt_count(PREEMPT_ACTIVE); | |
3538 | ||
3539 | /* we could miss a preemption opportunity between schedule and now */ | |
3540 | barrier(); | |
3541 | if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) | |
3542 | goto need_resched; | |
3543 | } | |
3544 | ||
3545 | #endif /* CONFIG_PREEMPT */ | |
3546 | ||
95cdf3b7 IM |
3547 | int default_wake_function(wait_queue_t *curr, unsigned mode, int sync, |
3548 | void *key) | |
1da177e4 | 3549 | { |
48f24c4d | 3550 | return try_to_wake_up(curr->private, mode, sync); |
1da177e4 | 3551 | } |
1da177e4 LT |
3552 | EXPORT_SYMBOL(default_wake_function); |
3553 | ||
3554 | /* | |
3555 | * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just | |
3556 | * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve | |
3557 | * number) then we wake all the non-exclusive tasks and one exclusive task. | |
3558 | * | |
3559 | * There are circumstances in which we can try to wake a task which has already | |
3560 | * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns | |
3561 | * zero in this (rare) case, and we handle it by continuing to scan the queue. | |
3562 | */ | |
3563 | static void __wake_up_common(wait_queue_head_t *q, unsigned int mode, | |
3564 | int nr_exclusive, int sync, void *key) | |
3565 | { | |
3566 | struct list_head *tmp, *next; | |
3567 | ||
3568 | list_for_each_safe(tmp, next, &q->task_list) { | |
48f24c4d IM |
3569 | wait_queue_t *curr = list_entry(tmp, wait_queue_t, task_list); |
3570 | unsigned flags = curr->flags; | |
3571 | ||
1da177e4 | 3572 | if (curr->func(curr, mode, sync, key) && |
48f24c4d | 3573 | (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive) |
1da177e4 LT |
3574 | break; |
3575 | } | |
3576 | } | |
3577 | ||
3578 | /** | |
3579 | * __wake_up - wake up threads blocked on a waitqueue. | |
3580 | * @q: the waitqueue | |
3581 | * @mode: which threads | |
3582 | * @nr_exclusive: how many wake-one or wake-many threads to wake up | |
67be2dd1 | 3583 | * @key: is directly passed to the wakeup function |
1da177e4 LT |
3584 | */ |
3585 | void fastcall __wake_up(wait_queue_head_t *q, unsigned int mode, | |
95cdf3b7 | 3586 | int nr_exclusive, void *key) |
1da177e4 LT |
3587 | { |
3588 | unsigned long flags; | |
3589 | ||
3590 | spin_lock_irqsave(&q->lock, flags); | |
3591 | __wake_up_common(q, mode, nr_exclusive, 0, key); | |
3592 | spin_unlock_irqrestore(&q->lock, flags); | |
3593 | } | |
1da177e4 LT |
3594 | EXPORT_SYMBOL(__wake_up); |
3595 | ||
3596 | /* | |
3597 | * Same as __wake_up but called with the spinlock in wait_queue_head_t held. | |
3598 | */ | |
3599 | void fastcall __wake_up_locked(wait_queue_head_t *q, unsigned int mode) | |
3600 | { | |
3601 | __wake_up_common(q, mode, 1, 0, NULL); | |
3602 | } | |
3603 | ||
3604 | /** | |
67be2dd1 | 3605 | * __wake_up_sync - wake up threads blocked on a waitqueue. |
1da177e4 LT |
3606 | * @q: the waitqueue |
3607 | * @mode: which threads | |
3608 | * @nr_exclusive: how many wake-one or wake-many threads to wake up | |
3609 | * | |
3610 | * The sync wakeup differs that the waker knows that it will schedule | |
3611 | * away soon, so while the target thread will be woken up, it will not | |
3612 | * be migrated to another CPU - ie. the two threads are 'synchronized' | |
3613 | * with each other. This can prevent needless bouncing between CPUs. | |
3614 | * | |
3615 | * On UP it can prevent extra preemption. | |
3616 | */ | |
95cdf3b7 IM |
3617 | void fastcall |
3618 | __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive) | |
1da177e4 LT |
3619 | { |
3620 | unsigned long flags; | |
3621 | int sync = 1; | |
3622 | ||
3623 | if (unlikely(!q)) | |
3624 | return; | |
3625 | ||
3626 | if (unlikely(!nr_exclusive)) | |
3627 | sync = 0; | |
3628 | ||
3629 | spin_lock_irqsave(&q->lock, flags); | |
3630 | __wake_up_common(q, mode, nr_exclusive, sync, NULL); | |
3631 | spin_unlock_irqrestore(&q->lock, flags); | |
3632 | } | |
3633 | EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */ | |
3634 | ||
3635 | void fastcall complete(struct completion *x) | |
3636 | { | |
3637 | unsigned long flags; | |
3638 | ||
3639 | spin_lock_irqsave(&x->wait.lock, flags); | |
3640 | x->done++; | |
3641 | __wake_up_common(&x->wait, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, | |
3642 | 1, 0, NULL); | |
3643 | spin_unlock_irqrestore(&x->wait.lock, flags); | |
3644 | } | |
3645 | EXPORT_SYMBOL(complete); | |
3646 | ||
3647 | void fastcall complete_all(struct completion *x) | |
3648 | { | |
3649 | unsigned long flags; | |
3650 | ||
3651 | spin_lock_irqsave(&x->wait.lock, flags); | |
3652 | x->done += UINT_MAX/2; | |
3653 | __wake_up_common(&x->wait, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, | |
3654 | 0, 0, NULL); | |
3655 | spin_unlock_irqrestore(&x->wait.lock, flags); | |
3656 | } | |
3657 | EXPORT_SYMBOL(complete_all); | |
3658 | ||
3659 | void fastcall __sched wait_for_completion(struct completion *x) | |
3660 | { | |
3661 | might_sleep(); | |
48f24c4d | 3662 | |
1da177e4 LT |
3663 | spin_lock_irq(&x->wait.lock); |
3664 | if (!x->done) { | |
3665 | DECLARE_WAITQUEUE(wait, current); | |
3666 | ||
3667 | wait.flags |= WQ_FLAG_EXCLUSIVE; | |
3668 | __add_wait_queue_tail(&x->wait, &wait); | |
3669 | do { | |
3670 | __set_current_state(TASK_UNINTERRUPTIBLE); | |
3671 | spin_unlock_irq(&x->wait.lock); | |
3672 | schedule(); | |
3673 | spin_lock_irq(&x->wait.lock); | |
3674 | } while (!x->done); | |
3675 | __remove_wait_queue(&x->wait, &wait); | |
3676 | } | |
3677 | x->done--; | |
3678 | spin_unlock_irq(&x->wait.lock); | |
3679 | } | |
3680 | EXPORT_SYMBOL(wait_for_completion); | |
3681 | ||
3682 | unsigned long fastcall __sched | |
3683 | wait_for_completion_timeout(struct completion *x, unsigned long timeout) | |
3684 | { | |
3685 | might_sleep(); | |
3686 | ||
3687 | spin_lock_irq(&x->wait.lock); | |
3688 | if (!x->done) { | |
3689 | DECLARE_WAITQUEUE(wait, current); | |
3690 | ||
3691 | wait.flags |= WQ_FLAG_EXCLUSIVE; | |
3692 | __add_wait_queue_tail(&x->wait, &wait); | |
3693 | do { | |
3694 | __set_current_state(TASK_UNINTERRUPTIBLE); | |
3695 | spin_unlock_irq(&x->wait.lock); | |
3696 | timeout = schedule_timeout(timeout); | |
3697 | spin_lock_irq(&x->wait.lock); | |
3698 | if (!timeout) { | |
3699 | __remove_wait_queue(&x->wait, &wait); | |
3700 | goto out; | |
3701 | } | |
3702 | } while (!x->done); | |
3703 | __remove_wait_queue(&x->wait, &wait); | |
3704 | } | |
3705 | x->done--; | |
3706 | out: | |
3707 | spin_unlock_irq(&x->wait.lock); | |
3708 | return timeout; | |
3709 | } | |
3710 | EXPORT_SYMBOL(wait_for_completion_timeout); | |
3711 | ||
3712 | int fastcall __sched wait_for_completion_interruptible(struct completion *x) | |
3713 | { | |
3714 | int ret = 0; | |
3715 | ||
3716 | might_sleep(); | |
3717 | ||
3718 | spin_lock_irq(&x->wait.lock); | |
3719 | if (!x->done) { | |
3720 | DECLARE_WAITQUEUE(wait, current); | |
3721 | ||
3722 | wait.flags |= WQ_FLAG_EXCLUSIVE; | |
3723 | __add_wait_queue_tail(&x->wait, &wait); | |
3724 | do { | |
3725 | if (signal_pending(current)) { | |
3726 | ret = -ERESTARTSYS; | |
3727 | __remove_wait_queue(&x->wait, &wait); | |
3728 | goto out; | |
3729 | } | |
3730 | __set_current_state(TASK_INTERRUPTIBLE); | |
3731 | spin_unlock_irq(&x->wait.lock); | |
3732 | schedule(); | |
3733 | spin_lock_irq(&x->wait.lock); | |
3734 | } while (!x->done); | |
3735 | __remove_wait_queue(&x->wait, &wait); | |
3736 | } | |
3737 | x->done--; | |
3738 | out: | |
3739 | spin_unlock_irq(&x->wait.lock); | |
3740 | ||
3741 | return ret; | |
3742 | } | |
3743 | EXPORT_SYMBOL(wait_for_completion_interruptible); | |
3744 | ||
3745 | unsigned long fastcall __sched | |
3746 | wait_for_completion_interruptible_timeout(struct completion *x, | |
3747 | unsigned long timeout) | |
3748 | { | |
3749 | might_sleep(); | |
3750 | ||
3751 | spin_lock_irq(&x->wait.lock); | |
3752 | if (!x->done) { | |
3753 | DECLARE_WAITQUEUE(wait, current); | |
3754 | ||
3755 | wait.flags |= WQ_FLAG_EXCLUSIVE; | |
3756 | __add_wait_queue_tail(&x->wait, &wait); | |
3757 | do { | |
3758 | if (signal_pending(current)) { | |
3759 | timeout = -ERESTARTSYS; | |
3760 | __remove_wait_queue(&x->wait, &wait); | |
3761 | goto out; | |
3762 | } | |
3763 | __set_current_state(TASK_INTERRUPTIBLE); | |
3764 | spin_unlock_irq(&x->wait.lock); | |
3765 | timeout = schedule_timeout(timeout); | |
3766 | spin_lock_irq(&x->wait.lock); | |
3767 | if (!timeout) { | |
3768 | __remove_wait_queue(&x->wait, &wait); | |
3769 | goto out; | |
3770 | } | |
3771 | } while (!x->done); | |
3772 | __remove_wait_queue(&x->wait, &wait); | |
3773 | } | |
3774 | x->done--; | |
3775 | out: | |
3776 | spin_unlock_irq(&x->wait.lock); | |
3777 | return timeout; | |
3778 | } | |
3779 | EXPORT_SYMBOL(wait_for_completion_interruptible_timeout); | |
3780 | ||
3781 | ||
3782 | #define SLEEP_ON_VAR \ | |
3783 | unsigned long flags; \ | |
3784 | wait_queue_t wait; \ | |
3785 | init_waitqueue_entry(&wait, current); | |
3786 | ||
3787 | #define SLEEP_ON_HEAD \ | |
3788 | spin_lock_irqsave(&q->lock,flags); \ | |
3789 | __add_wait_queue(q, &wait); \ | |
3790 | spin_unlock(&q->lock); | |
3791 | ||
3792 | #define SLEEP_ON_TAIL \ | |
3793 | spin_lock_irq(&q->lock); \ | |
3794 | __remove_wait_queue(q, &wait); \ | |
3795 | spin_unlock_irqrestore(&q->lock, flags); | |
3796 | ||
3797 | void fastcall __sched interruptible_sleep_on(wait_queue_head_t *q) | |
3798 | { | |
3799 | SLEEP_ON_VAR | |
3800 | ||
3801 | current->state = TASK_INTERRUPTIBLE; | |
3802 | ||
3803 | SLEEP_ON_HEAD | |
3804 | schedule(); | |
3805 | SLEEP_ON_TAIL | |
3806 | } | |
1da177e4 LT |
3807 | EXPORT_SYMBOL(interruptible_sleep_on); |
3808 | ||
95cdf3b7 IM |
3809 | long fastcall __sched |
3810 | interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout) | |
1da177e4 LT |
3811 | { |
3812 | SLEEP_ON_VAR | |
3813 | ||
3814 | current->state = TASK_INTERRUPTIBLE; | |
3815 | ||
3816 | SLEEP_ON_HEAD | |
3817 | timeout = schedule_timeout(timeout); | |
3818 | SLEEP_ON_TAIL | |
3819 | ||
3820 | return timeout; | |
3821 | } | |
1da177e4 LT |
3822 | EXPORT_SYMBOL(interruptible_sleep_on_timeout); |
3823 | ||
3824 | void fastcall __sched sleep_on(wait_queue_head_t *q) | |
3825 | { | |
3826 | SLEEP_ON_VAR | |
3827 | ||
3828 | current->state = TASK_UNINTERRUPTIBLE; | |
3829 | ||
3830 | SLEEP_ON_HEAD | |
3831 | schedule(); | |
3832 | SLEEP_ON_TAIL | |
3833 | } | |
1da177e4 LT |
3834 | EXPORT_SYMBOL(sleep_on); |
3835 | ||
3836 | long fastcall __sched sleep_on_timeout(wait_queue_head_t *q, long timeout) | |
3837 | { | |
3838 | SLEEP_ON_VAR | |
3839 | ||
3840 | current->state = TASK_UNINTERRUPTIBLE; | |
3841 | ||
3842 | SLEEP_ON_HEAD | |
3843 | timeout = schedule_timeout(timeout); | |
3844 | SLEEP_ON_TAIL | |
3845 | ||
3846 | return timeout; | |
3847 | } | |
3848 | ||
3849 | EXPORT_SYMBOL(sleep_on_timeout); | |
3850 | ||
b29739f9 IM |
3851 | #ifdef CONFIG_RT_MUTEXES |
3852 | ||
3853 | /* | |
3854 | * rt_mutex_setprio - set the current priority of a task | |
3855 | * @p: task | |
3856 | * @prio: prio value (kernel-internal form) | |
3857 | * | |
3858 | * This function changes the 'effective' priority of a task. It does | |
3859 | * not touch ->normal_prio like __setscheduler(). | |
3860 | * | |
3861 | * Used by the rt_mutex code to implement priority inheritance logic. | |
3862 | */ | |
36c8b586 | 3863 | void rt_mutex_setprio(struct task_struct *p, int prio) |
b29739f9 IM |
3864 | { |
3865 | unsigned long flags; | |
dd41f596 | 3866 | int oldprio, on_rq; |
70b97a7f | 3867 | struct rq *rq; |
dd41f596 | 3868 | u64 now; |
b29739f9 IM |
3869 | |
3870 | BUG_ON(prio < 0 || prio > MAX_PRIO); | |
3871 | ||
3872 | rq = task_rq_lock(p, &flags); | |
dd41f596 | 3873 | now = rq_clock(rq); |
b29739f9 | 3874 | |
d5f9f942 | 3875 | oldprio = p->prio; |
dd41f596 IM |
3876 | on_rq = p->se.on_rq; |
3877 | if (on_rq) | |
3878 | dequeue_task(rq, p, 0, now); | |
3879 | ||
3880 | if (rt_prio(prio)) | |
3881 | p->sched_class = &rt_sched_class; | |
3882 | else | |
3883 | p->sched_class = &fair_sched_class; | |
3884 | ||
b29739f9 IM |
3885 | p->prio = prio; |
3886 | ||
dd41f596 IM |
3887 | if (on_rq) { |
3888 | enqueue_task(rq, p, 0, now); | |
b29739f9 IM |
3889 | /* |
3890 | * Reschedule if we are currently running on this runqueue and | |
d5f9f942 AM |
3891 | * our priority decreased, or if we are not currently running on |
3892 | * this runqueue and our priority is higher than the current's | |
b29739f9 | 3893 | */ |
d5f9f942 AM |
3894 | if (task_running(rq, p)) { |
3895 | if (p->prio > oldprio) | |
3896 | resched_task(rq->curr); | |
dd41f596 IM |
3897 | } else { |
3898 | check_preempt_curr(rq, p); | |
3899 | } | |
b29739f9 IM |
3900 | } |
3901 | task_rq_unlock(rq, &flags); | |
3902 | } | |
3903 | ||
3904 | #endif | |
3905 | ||
36c8b586 | 3906 | void set_user_nice(struct task_struct *p, long nice) |
1da177e4 | 3907 | { |
dd41f596 | 3908 | int old_prio, delta, on_rq; |
1da177e4 | 3909 | unsigned long flags; |
70b97a7f | 3910 | struct rq *rq; |
dd41f596 | 3911 | u64 now; |
1da177e4 LT |
3912 | |
3913 | if (TASK_NICE(p) == nice || nice < -20 || nice > 19) | |
3914 | return; | |
3915 | /* | |
3916 | * We have to be careful, if called from sys_setpriority(), | |
3917 | * the task might be in the middle of scheduling on another CPU. | |
3918 | */ | |
3919 | rq = task_rq_lock(p, &flags); | |
dd41f596 | 3920 | now = rq_clock(rq); |
1da177e4 LT |
3921 | /* |
3922 | * The RT priorities are set via sched_setscheduler(), but we still | |
3923 | * allow the 'normal' nice value to be set - but as expected | |
3924 | * it wont have any effect on scheduling until the task is | |
dd41f596 | 3925 | * SCHED_FIFO/SCHED_RR: |
1da177e4 | 3926 | */ |
e05606d3 | 3927 | if (task_has_rt_policy(p)) { |
1da177e4 LT |
3928 | p->static_prio = NICE_TO_PRIO(nice); |
3929 | goto out_unlock; | |
3930 | } | |
dd41f596 IM |
3931 | on_rq = p->se.on_rq; |
3932 | if (on_rq) { | |
3933 | dequeue_task(rq, p, 0, now); | |
3934 | dec_load(rq, p, now); | |
2dd73a4f | 3935 | } |
1da177e4 | 3936 | |
1da177e4 | 3937 | p->static_prio = NICE_TO_PRIO(nice); |
2dd73a4f | 3938 | set_load_weight(p); |
b29739f9 IM |
3939 | old_prio = p->prio; |
3940 | p->prio = effective_prio(p); | |
3941 | delta = p->prio - old_prio; | |
1da177e4 | 3942 | |
dd41f596 IM |
3943 | if (on_rq) { |
3944 | enqueue_task(rq, p, 0, now); | |
3945 | inc_load(rq, p, now); | |
1da177e4 | 3946 | /* |
d5f9f942 AM |
3947 | * If the task increased its priority or is running and |
3948 | * lowered its priority, then reschedule its CPU: | |
1da177e4 | 3949 | */ |
d5f9f942 | 3950 | if (delta < 0 || (delta > 0 && task_running(rq, p))) |
1da177e4 LT |
3951 | resched_task(rq->curr); |
3952 | } | |
3953 | out_unlock: | |
3954 | task_rq_unlock(rq, &flags); | |
3955 | } | |
1da177e4 LT |
3956 | EXPORT_SYMBOL(set_user_nice); |
3957 | ||
e43379f1 MM |
3958 | /* |
3959 | * can_nice - check if a task can reduce its nice value | |
3960 | * @p: task | |
3961 | * @nice: nice value | |
3962 | */ | |
36c8b586 | 3963 | int can_nice(const struct task_struct *p, const int nice) |
e43379f1 | 3964 | { |
024f4747 MM |
3965 | /* convert nice value [19,-20] to rlimit style value [1,40] */ |
3966 | int nice_rlim = 20 - nice; | |
48f24c4d | 3967 | |
e43379f1 MM |
3968 | return (nice_rlim <= p->signal->rlim[RLIMIT_NICE].rlim_cur || |
3969 | capable(CAP_SYS_NICE)); | |
3970 | } | |
3971 | ||
1da177e4 LT |
3972 | #ifdef __ARCH_WANT_SYS_NICE |
3973 | ||
3974 | /* | |
3975 | * sys_nice - change the priority of the current process. | |
3976 | * @increment: priority increment | |
3977 | * | |
3978 | * sys_setpriority is a more generic, but much slower function that | |
3979 | * does similar things. | |
3980 | */ | |
3981 | asmlinkage long sys_nice(int increment) | |
3982 | { | |
48f24c4d | 3983 | long nice, retval; |
1da177e4 LT |
3984 | |
3985 | /* | |
3986 | * Setpriority might change our priority at the same moment. | |
3987 | * We don't have to worry. Conceptually one call occurs first | |
3988 | * and we have a single winner. | |
3989 | */ | |
e43379f1 MM |
3990 | if (increment < -40) |
3991 | increment = -40; | |
1da177e4 LT |
3992 | if (increment > 40) |
3993 | increment = 40; | |
3994 | ||
3995 | nice = PRIO_TO_NICE(current->static_prio) + increment; | |
3996 | if (nice < -20) | |
3997 | nice = -20; | |
3998 | if (nice > 19) | |
3999 | nice = 19; | |
4000 | ||
e43379f1 MM |
4001 | if (increment < 0 && !can_nice(current, nice)) |
4002 | return -EPERM; | |
4003 | ||
1da177e4 LT |
4004 | retval = security_task_setnice(current, nice); |
4005 | if (retval) | |
4006 | return retval; | |
4007 | ||
4008 | set_user_nice(current, nice); | |
4009 | return 0; | |
4010 | } | |
4011 | ||
4012 | #endif | |
4013 | ||
4014 | /** | |
4015 | * task_prio - return the priority value of a given task. | |
4016 | * @p: the task in question. | |
4017 | * | |
4018 | * This is the priority value as seen by users in /proc. | |
4019 | * RT tasks are offset by -200. Normal tasks are centered | |
4020 | * around 0, value goes from -16 to +15. | |
4021 | */ | |
36c8b586 | 4022 | int task_prio(const struct task_struct *p) |
1da177e4 LT |
4023 | { |
4024 | return p->prio - MAX_RT_PRIO; | |
4025 | } | |
4026 | ||
4027 | /** | |
4028 | * task_nice - return the nice value of a given task. | |
4029 | * @p: the task in question. | |
4030 | */ | |
36c8b586 | 4031 | int task_nice(const struct task_struct *p) |
1da177e4 LT |
4032 | { |
4033 | return TASK_NICE(p); | |
4034 | } | |
1da177e4 | 4035 | EXPORT_SYMBOL_GPL(task_nice); |
1da177e4 LT |
4036 | |
4037 | /** | |
4038 | * idle_cpu - is a given cpu idle currently? | |
4039 | * @cpu: the processor in question. | |
4040 | */ | |
4041 | int idle_cpu(int cpu) | |
4042 | { | |
4043 | return cpu_curr(cpu) == cpu_rq(cpu)->idle; | |
4044 | } | |
4045 | ||
1da177e4 LT |
4046 | /** |
4047 | * idle_task - return the idle task for a given cpu. | |
4048 | * @cpu: the processor in question. | |
4049 | */ | |
36c8b586 | 4050 | struct task_struct *idle_task(int cpu) |
1da177e4 LT |
4051 | { |
4052 | return cpu_rq(cpu)->idle; | |
4053 | } | |
4054 | ||
4055 | /** | |
4056 | * find_process_by_pid - find a process with a matching PID value. | |
4057 | * @pid: the pid in question. | |
4058 | */ | |
36c8b586 | 4059 | static inline struct task_struct *find_process_by_pid(pid_t pid) |
1da177e4 LT |
4060 | { |
4061 | return pid ? find_task_by_pid(pid) : current; | |
4062 | } | |
4063 | ||
4064 | /* Actually do priority change: must hold rq lock. */ | |
dd41f596 IM |
4065 | static void |
4066 | __setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio) | |
1da177e4 | 4067 | { |
dd41f596 | 4068 | BUG_ON(p->se.on_rq); |
48f24c4d | 4069 | |
1da177e4 | 4070 | p->policy = policy; |
dd41f596 IM |
4071 | switch (p->policy) { |
4072 | case SCHED_NORMAL: | |
4073 | case SCHED_BATCH: | |
4074 | case SCHED_IDLE: | |
4075 | p->sched_class = &fair_sched_class; | |
4076 | break; | |
4077 | case SCHED_FIFO: | |
4078 | case SCHED_RR: | |
4079 | p->sched_class = &rt_sched_class; | |
4080 | break; | |
4081 | } | |
4082 | ||
1da177e4 | 4083 | p->rt_priority = prio; |
b29739f9 IM |
4084 | p->normal_prio = normal_prio(p); |
4085 | /* we are holding p->pi_lock already */ | |
4086 | p->prio = rt_mutex_getprio(p); | |
2dd73a4f | 4087 | set_load_weight(p); |
1da177e4 LT |
4088 | } |
4089 | ||
4090 | /** | |
72fd4a35 | 4091 | * sched_setscheduler - change the scheduling policy and/or RT priority of a thread. |
1da177e4 LT |
4092 | * @p: the task in question. |
4093 | * @policy: new policy. | |
4094 | * @param: structure containing the new RT priority. | |
5fe1d75f | 4095 | * |
72fd4a35 | 4096 | * NOTE that the task may be already dead. |
1da177e4 | 4097 | */ |
95cdf3b7 IM |
4098 | int sched_setscheduler(struct task_struct *p, int policy, |
4099 | struct sched_param *param) | |
1da177e4 | 4100 | { |
dd41f596 | 4101 | int retval, oldprio, oldpolicy = -1, on_rq; |
1da177e4 | 4102 | unsigned long flags; |
70b97a7f | 4103 | struct rq *rq; |
1da177e4 | 4104 | |
66e5393a SR |
4105 | /* may grab non-irq protected spin_locks */ |
4106 | BUG_ON(in_interrupt()); | |
1da177e4 LT |
4107 | recheck: |
4108 | /* double check policy once rq lock held */ | |
4109 | if (policy < 0) | |
4110 | policy = oldpolicy = p->policy; | |
4111 | else if (policy != SCHED_FIFO && policy != SCHED_RR && | |
dd41f596 IM |
4112 | policy != SCHED_NORMAL && policy != SCHED_BATCH && |
4113 | policy != SCHED_IDLE) | |
b0a9499c | 4114 | return -EINVAL; |
1da177e4 LT |
4115 | /* |
4116 | * Valid priorities for SCHED_FIFO and SCHED_RR are | |
dd41f596 IM |
4117 | * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL, |
4118 | * SCHED_BATCH and SCHED_IDLE is 0. | |
1da177e4 LT |
4119 | */ |
4120 | if (param->sched_priority < 0 || | |
95cdf3b7 | 4121 | (p->mm && param->sched_priority > MAX_USER_RT_PRIO-1) || |
d46523ea | 4122 | (!p->mm && param->sched_priority > MAX_RT_PRIO-1)) |
1da177e4 | 4123 | return -EINVAL; |
e05606d3 | 4124 | if (rt_policy(policy) != (param->sched_priority != 0)) |
1da177e4 LT |
4125 | return -EINVAL; |
4126 | ||
37e4ab3f OC |
4127 | /* |
4128 | * Allow unprivileged RT tasks to decrease priority: | |
4129 | */ | |
4130 | if (!capable(CAP_SYS_NICE)) { | |
e05606d3 | 4131 | if (rt_policy(policy)) { |
8dc3e909 | 4132 | unsigned long rlim_rtprio; |
8dc3e909 ON |
4133 | |
4134 | if (!lock_task_sighand(p, &flags)) | |
4135 | return -ESRCH; | |
4136 | rlim_rtprio = p->signal->rlim[RLIMIT_RTPRIO].rlim_cur; | |
4137 | unlock_task_sighand(p, &flags); | |
4138 | ||
4139 | /* can't set/change the rt policy */ | |
4140 | if (policy != p->policy && !rlim_rtprio) | |
4141 | return -EPERM; | |
4142 | ||
4143 | /* can't increase priority */ | |
4144 | if (param->sched_priority > p->rt_priority && | |
4145 | param->sched_priority > rlim_rtprio) | |
4146 | return -EPERM; | |
4147 | } | |
dd41f596 IM |
4148 | /* |
4149 | * Like positive nice levels, dont allow tasks to | |
4150 | * move out of SCHED_IDLE either: | |
4151 | */ | |
4152 | if (p->policy == SCHED_IDLE && policy != SCHED_IDLE) | |
4153 | return -EPERM; | |
5fe1d75f | 4154 | |
37e4ab3f OC |
4155 | /* can't change other user's priorities */ |
4156 | if ((current->euid != p->euid) && | |
4157 | (current->euid != p->uid)) | |
4158 | return -EPERM; | |
4159 | } | |
1da177e4 LT |
4160 | |
4161 | retval = security_task_setscheduler(p, policy, param); | |
4162 | if (retval) | |
4163 | return retval; | |
b29739f9 IM |
4164 | /* |
4165 | * make sure no PI-waiters arrive (or leave) while we are | |
4166 | * changing the priority of the task: | |
4167 | */ | |
4168 | spin_lock_irqsave(&p->pi_lock, flags); | |
1da177e4 LT |
4169 | /* |
4170 | * To be able to change p->policy safely, the apropriate | |
4171 | * runqueue lock must be held. | |
4172 | */ | |
b29739f9 | 4173 | rq = __task_rq_lock(p); |
1da177e4 LT |
4174 | /* recheck policy now with rq lock held */ |
4175 | if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) { | |
4176 | policy = oldpolicy = -1; | |
b29739f9 IM |
4177 | __task_rq_unlock(rq); |
4178 | spin_unlock_irqrestore(&p->pi_lock, flags); | |
1da177e4 LT |
4179 | goto recheck; |
4180 | } | |
dd41f596 IM |
4181 | on_rq = p->se.on_rq; |
4182 | if (on_rq) | |
4183 | deactivate_task(rq, p, 0); | |
1da177e4 | 4184 | oldprio = p->prio; |
dd41f596 IM |
4185 | __setscheduler(rq, p, policy, param->sched_priority); |
4186 | if (on_rq) { | |
4187 | activate_task(rq, p, 0); | |
1da177e4 LT |
4188 | /* |
4189 | * Reschedule if we are currently running on this runqueue and | |
d5f9f942 AM |
4190 | * our priority decreased, or if we are not currently running on |
4191 | * this runqueue and our priority is higher than the current's | |
1da177e4 | 4192 | */ |
d5f9f942 AM |
4193 | if (task_running(rq, p)) { |
4194 | if (p->prio > oldprio) | |
4195 | resched_task(rq->curr); | |
dd41f596 IM |
4196 | } else { |
4197 | check_preempt_curr(rq, p); | |
4198 | } | |
1da177e4 | 4199 | } |
b29739f9 IM |
4200 | __task_rq_unlock(rq); |
4201 | spin_unlock_irqrestore(&p->pi_lock, flags); | |
4202 | ||
95e02ca9 TG |
4203 | rt_mutex_adjust_pi(p); |
4204 | ||
1da177e4 LT |
4205 | return 0; |
4206 | } | |
4207 | EXPORT_SYMBOL_GPL(sched_setscheduler); | |
4208 | ||
95cdf3b7 IM |
4209 | static int |
4210 | do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param) | |
1da177e4 | 4211 | { |
1da177e4 LT |
4212 | struct sched_param lparam; |
4213 | struct task_struct *p; | |
36c8b586 | 4214 | int retval; |
1da177e4 LT |
4215 | |
4216 | if (!param || pid < 0) | |
4217 | return -EINVAL; | |
4218 | if (copy_from_user(&lparam, param, sizeof(struct sched_param))) | |
4219 | return -EFAULT; | |
5fe1d75f ON |
4220 | |
4221 | rcu_read_lock(); | |
4222 | retval = -ESRCH; | |
1da177e4 | 4223 | p = find_process_by_pid(pid); |
5fe1d75f ON |
4224 | if (p != NULL) |
4225 | retval = sched_setscheduler(p, policy, &lparam); | |
4226 | rcu_read_unlock(); | |
36c8b586 | 4227 | |
1da177e4 LT |
4228 | return retval; |
4229 | } | |
4230 | ||
4231 | /** | |
4232 | * sys_sched_setscheduler - set/change the scheduler policy and RT priority | |
4233 | * @pid: the pid in question. | |
4234 | * @policy: new policy. | |
4235 | * @param: structure containing the new RT priority. | |
4236 | */ | |
4237 | asmlinkage long sys_sched_setscheduler(pid_t pid, int policy, | |
4238 | struct sched_param __user *param) | |
4239 | { | |
c21761f1 JB |
4240 | /* negative values for policy are not valid */ |
4241 | if (policy < 0) | |
4242 | return -EINVAL; | |
4243 | ||
1da177e4 LT |
4244 | return do_sched_setscheduler(pid, policy, param); |
4245 | } | |
4246 | ||
4247 | /** | |
4248 | * sys_sched_setparam - set/change the RT priority of a thread | |
4249 | * @pid: the pid in question. | |
4250 | * @param: structure containing the new RT priority. | |
4251 | */ | |
4252 | asmlinkage long sys_sched_setparam(pid_t pid, struct sched_param __user *param) | |
4253 | { | |
4254 | return do_sched_setscheduler(pid, -1, param); | |
4255 | } | |
4256 | ||
4257 | /** | |
4258 | * sys_sched_getscheduler - get the policy (scheduling class) of a thread | |
4259 | * @pid: the pid in question. | |
4260 | */ | |
4261 | asmlinkage long sys_sched_getscheduler(pid_t pid) | |
4262 | { | |
36c8b586 | 4263 | struct task_struct *p; |
1da177e4 | 4264 | int retval = -EINVAL; |
1da177e4 LT |
4265 | |
4266 | if (pid < 0) | |
4267 | goto out_nounlock; | |
4268 | ||
4269 | retval = -ESRCH; | |
4270 | read_lock(&tasklist_lock); | |
4271 | p = find_process_by_pid(pid); | |
4272 | if (p) { | |
4273 | retval = security_task_getscheduler(p); | |
4274 | if (!retval) | |
4275 | retval = p->policy; | |
4276 | } | |
4277 | read_unlock(&tasklist_lock); | |
4278 | ||
4279 | out_nounlock: | |
4280 | return retval; | |
4281 | } | |
4282 | ||
4283 | /** | |
4284 | * sys_sched_getscheduler - get the RT priority of a thread | |
4285 | * @pid: the pid in question. | |
4286 | * @param: structure containing the RT priority. | |
4287 | */ | |
4288 | asmlinkage long sys_sched_getparam(pid_t pid, struct sched_param __user *param) | |
4289 | { | |
4290 | struct sched_param lp; | |
36c8b586 | 4291 | struct task_struct *p; |
1da177e4 | 4292 | int retval = -EINVAL; |
1da177e4 LT |
4293 | |
4294 | if (!param || pid < 0) | |
4295 | goto out_nounlock; | |
4296 | ||
4297 | read_lock(&tasklist_lock); | |
4298 | p = find_process_by_pid(pid); | |
4299 | retval = -ESRCH; | |
4300 | if (!p) | |
4301 | goto out_unlock; | |
4302 | ||
4303 | retval = security_task_getscheduler(p); | |
4304 | if (retval) | |
4305 | goto out_unlock; | |
4306 | ||
4307 | lp.sched_priority = p->rt_priority; | |
4308 | read_unlock(&tasklist_lock); | |
4309 | ||
4310 | /* | |
4311 | * This one might sleep, we cannot do it with a spinlock held ... | |
4312 | */ | |
4313 | retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0; | |
4314 | ||
4315 | out_nounlock: | |
4316 | return retval; | |
4317 | ||
4318 | out_unlock: | |
4319 | read_unlock(&tasklist_lock); | |
4320 | return retval; | |
4321 | } | |
4322 | ||
4323 | long sched_setaffinity(pid_t pid, cpumask_t new_mask) | |
4324 | { | |
1da177e4 | 4325 | cpumask_t cpus_allowed; |
36c8b586 IM |
4326 | struct task_struct *p; |
4327 | int retval; | |
1da177e4 | 4328 | |
5be9361c | 4329 | mutex_lock(&sched_hotcpu_mutex); |
1da177e4 LT |
4330 | read_lock(&tasklist_lock); |
4331 | ||
4332 | p = find_process_by_pid(pid); | |
4333 | if (!p) { | |
4334 | read_unlock(&tasklist_lock); | |
5be9361c | 4335 | mutex_unlock(&sched_hotcpu_mutex); |
1da177e4 LT |
4336 | return -ESRCH; |
4337 | } | |
4338 | ||
4339 | /* | |
4340 | * It is not safe to call set_cpus_allowed with the | |
4341 | * tasklist_lock held. We will bump the task_struct's | |
4342 | * usage count and then drop tasklist_lock. | |
4343 | */ | |
4344 | get_task_struct(p); | |
4345 | read_unlock(&tasklist_lock); | |
4346 | ||
4347 | retval = -EPERM; | |
4348 | if ((current->euid != p->euid) && (current->euid != p->uid) && | |
4349 | !capable(CAP_SYS_NICE)) | |
4350 | goto out_unlock; | |
4351 | ||
e7834f8f DQ |
4352 | retval = security_task_setscheduler(p, 0, NULL); |
4353 | if (retval) | |
4354 | goto out_unlock; | |
4355 | ||
1da177e4 LT |
4356 | cpus_allowed = cpuset_cpus_allowed(p); |
4357 | cpus_and(new_mask, new_mask, cpus_allowed); | |
4358 | retval = set_cpus_allowed(p, new_mask); | |
4359 | ||
4360 | out_unlock: | |
4361 | put_task_struct(p); | |
5be9361c | 4362 | mutex_unlock(&sched_hotcpu_mutex); |
1da177e4 LT |
4363 | return retval; |
4364 | } | |
4365 | ||
4366 | static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len, | |
4367 | cpumask_t *new_mask) | |
4368 | { | |
4369 | if (len < sizeof(cpumask_t)) { | |
4370 | memset(new_mask, 0, sizeof(cpumask_t)); | |
4371 | } else if (len > sizeof(cpumask_t)) { | |
4372 | len = sizeof(cpumask_t); | |
4373 | } | |
4374 | return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0; | |
4375 | } | |
4376 | ||
4377 | /** | |
4378 | * sys_sched_setaffinity - set the cpu affinity of a process | |
4379 | * @pid: pid of the process | |
4380 | * @len: length in bytes of the bitmask pointed to by user_mask_ptr | |
4381 | * @user_mask_ptr: user-space pointer to the new cpu mask | |
4382 | */ | |
4383 | asmlinkage long sys_sched_setaffinity(pid_t pid, unsigned int len, | |
4384 | unsigned long __user *user_mask_ptr) | |
4385 | { | |
4386 | cpumask_t new_mask; | |
4387 | int retval; | |
4388 | ||
4389 | retval = get_user_cpu_mask(user_mask_ptr, len, &new_mask); | |
4390 | if (retval) | |
4391 | return retval; | |
4392 | ||
4393 | return sched_setaffinity(pid, new_mask); | |
4394 | } | |
4395 | ||
4396 | /* | |
4397 | * Represents all cpu's present in the system | |
4398 | * In systems capable of hotplug, this map could dynamically grow | |
4399 | * as new cpu's are detected in the system via any platform specific | |
4400 | * method, such as ACPI for e.g. | |
4401 | */ | |
4402 | ||
4cef0c61 | 4403 | cpumask_t cpu_present_map __read_mostly; |
1da177e4 LT |
4404 | EXPORT_SYMBOL(cpu_present_map); |
4405 | ||
4406 | #ifndef CONFIG_SMP | |
4cef0c61 | 4407 | cpumask_t cpu_online_map __read_mostly = CPU_MASK_ALL; |
e16b38f7 GB |
4408 | EXPORT_SYMBOL(cpu_online_map); |
4409 | ||
4cef0c61 | 4410 | cpumask_t cpu_possible_map __read_mostly = CPU_MASK_ALL; |
e16b38f7 | 4411 | EXPORT_SYMBOL(cpu_possible_map); |
1da177e4 LT |
4412 | #endif |
4413 | ||
4414 | long sched_getaffinity(pid_t pid, cpumask_t *mask) | |
4415 | { | |
36c8b586 | 4416 | struct task_struct *p; |
1da177e4 | 4417 | int retval; |
1da177e4 | 4418 | |
5be9361c | 4419 | mutex_lock(&sched_hotcpu_mutex); |
1da177e4 LT |
4420 | read_lock(&tasklist_lock); |
4421 | ||
4422 | retval = -ESRCH; | |
4423 | p = find_process_by_pid(pid); | |
4424 | if (!p) | |
4425 | goto out_unlock; | |
4426 | ||
e7834f8f DQ |
4427 | retval = security_task_getscheduler(p); |
4428 | if (retval) | |
4429 | goto out_unlock; | |
4430 | ||
2f7016d9 | 4431 | cpus_and(*mask, p->cpus_allowed, cpu_online_map); |
1da177e4 LT |
4432 | |
4433 | out_unlock: | |
4434 | read_unlock(&tasklist_lock); | |
5be9361c | 4435 | mutex_unlock(&sched_hotcpu_mutex); |
1da177e4 LT |
4436 | if (retval) |
4437 | return retval; | |
4438 | ||
4439 | return 0; | |
4440 | } | |
4441 | ||
4442 | /** | |
4443 | * sys_sched_getaffinity - get the cpu affinity of a process | |
4444 | * @pid: pid of the process | |
4445 | * @len: length in bytes of the bitmask pointed to by user_mask_ptr | |
4446 | * @user_mask_ptr: user-space pointer to hold the current cpu mask | |
4447 | */ | |
4448 | asmlinkage long sys_sched_getaffinity(pid_t pid, unsigned int len, | |
4449 | unsigned long __user *user_mask_ptr) | |
4450 | { | |
4451 | int ret; | |
4452 | cpumask_t mask; | |
4453 | ||
4454 | if (len < sizeof(cpumask_t)) | |
4455 | return -EINVAL; | |
4456 | ||
4457 | ret = sched_getaffinity(pid, &mask); | |
4458 | if (ret < 0) | |
4459 | return ret; | |
4460 | ||
4461 | if (copy_to_user(user_mask_ptr, &mask, sizeof(cpumask_t))) | |
4462 | return -EFAULT; | |
4463 | ||
4464 | return sizeof(cpumask_t); | |
4465 | } | |
4466 | ||
4467 | /** | |
4468 | * sys_sched_yield - yield the current processor to other threads. | |
4469 | * | |
dd41f596 IM |
4470 | * This function yields the current CPU to other tasks. If there are no |
4471 | * other threads running on this CPU then this function will return. | |
1da177e4 LT |
4472 | */ |
4473 | asmlinkage long sys_sched_yield(void) | |
4474 | { | |
70b97a7f | 4475 | struct rq *rq = this_rq_lock(); |
1da177e4 LT |
4476 | |
4477 | schedstat_inc(rq, yld_cnt); | |
dd41f596 | 4478 | if (unlikely(rq->nr_running == 1)) |
1da177e4 | 4479 | schedstat_inc(rq, yld_act_empty); |
dd41f596 IM |
4480 | else |
4481 | current->sched_class->yield_task(rq, current); | |
1da177e4 LT |
4482 | |
4483 | /* | |
4484 | * Since we are going to call schedule() anyway, there's | |
4485 | * no need to preempt or enable interrupts: | |
4486 | */ | |
4487 | __release(rq->lock); | |
8a25d5de | 4488 | spin_release(&rq->lock.dep_map, 1, _THIS_IP_); |
1da177e4 LT |
4489 | _raw_spin_unlock(&rq->lock); |
4490 | preempt_enable_no_resched(); | |
4491 | ||
4492 | schedule(); | |
4493 | ||
4494 | return 0; | |
4495 | } | |
4496 | ||
e7b38404 | 4497 | static void __cond_resched(void) |
1da177e4 | 4498 | { |
8e0a43d8 IM |
4499 | #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP |
4500 | __might_sleep(__FILE__, __LINE__); | |
4501 | #endif | |
5bbcfd90 IM |
4502 | /* |
4503 | * The BKS might be reacquired before we have dropped | |
4504 | * PREEMPT_ACTIVE, which could trigger a second | |
4505 | * cond_resched() call. | |
4506 | */ | |
1da177e4 LT |
4507 | do { |
4508 | add_preempt_count(PREEMPT_ACTIVE); | |
4509 | schedule(); | |
4510 | sub_preempt_count(PREEMPT_ACTIVE); | |
4511 | } while (need_resched()); | |
4512 | } | |
4513 | ||
4514 | int __sched cond_resched(void) | |
4515 | { | |
9414232f IM |
4516 | if (need_resched() && !(preempt_count() & PREEMPT_ACTIVE) && |
4517 | system_state == SYSTEM_RUNNING) { | |
1da177e4 LT |
4518 | __cond_resched(); |
4519 | return 1; | |
4520 | } | |
4521 | return 0; | |
4522 | } | |
1da177e4 LT |
4523 | EXPORT_SYMBOL(cond_resched); |
4524 | ||
4525 | /* | |
4526 | * cond_resched_lock() - if a reschedule is pending, drop the given lock, | |
4527 | * call schedule, and on return reacquire the lock. | |
4528 | * | |
4529 | * This works OK both with and without CONFIG_PREEMPT. We do strange low-level | |
4530 | * operations here to prevent schedule() from being called twice (once via | |
4531 | * spin_unlock(), once by hand). | |
4532 | */ | |
95cdf3b7 | 4533 | int cond_resched_lock(spinlock_t *lock) |
1da177e4 | 4534 | { |
6df3cecb JK |
4535 | int ret = 0; |
4536 | ||
1da177e4 LT |
4537 | if (need_lockbreak(lock)) { |
4538 | spin_unlock(lock); | |
4539 | cpu_relax(); | |
6df3cecb | 4540 | ret = 1; |
1da177e4 LT |
4541 | spin_lock(lock); |
4542 | } | |
9414232f | 4543 | if (need_resched() && system_state == SYSTEM_RUNNING) { |
8a25d5de | 4544 | spin_release(&lock->dep_map, 1, _THIS_IP_); |
1da177e4 LT |
4545 | _raw_spin_unlock(lock); |
4546 | preempt_enable_no_resched(); | |
4547 | __cond_resched(); | |
6df3cecb | 4548 | ret = 1; |
1da177e4 | 4549 | spin_lock(lock); |
1da177e4 | 4550 | } |
6df3cecb | 4551 | return ret; |
1da177e4 | 4552 | } |
1da177e4 LT |
4553 | EXPORT_SYMBOL(cond_resched_lock); |
4554 | ||
4555 | int __sched cond_resched_softirq(void) | |
4556 | { | |
4557 | BUG_ON(!in_softirq()); | |
4558 | ||
9414232f | 4559 | if (need_resched() && system_state == SYSTEM_RUNNING) { |
98d82567 | 4560 | local_bh_enable(); |
1da177e4 LT |
4561 | __cond_resched(); |
4562 | local_bh_disable(); | |
4563 | return 1; | |
4564 | } | |
4565 | return 0; | |
4566 | } | |
1da177e4 LT |
4567 | EXPORT_SYMBOL(cond_resched_softirq); |
4568 | ||
1da177e4 LT |
4569 | /** |
4570 | * yield - yield the current processor to other threads. | |
4571 | * | |
72fd4a35 | 4572 | * This is a shortcut for kernel-space yielding - it marks the |
1da177e4 LT |
4573 | * thread runnable and calls sys_sched_yield(). |
4574 | */ | |
4575 | void __sched yield(void) | |
4576 | { | |
4577 | set_current_state(TASK_RUNNING); | |
4578 | sys_sched_yield(); | |
4579 | } | |
1da177e4 LT |
4580 | EXPORT_SYMBOL(yield); |
4581 | ||
4582 | /* | |
4583 | * This task is about to go to sleep on IO. Increment rq->nr_iowait so | |
4584 | * that process accounting knows that this is a task in IO wait state. | |
4585 | * | |
4586 | * But don't do that if it is a deliberate, throttling IO wait (this task | |
4587 | * has set its backing_dev_info: the queue against which it should throttle) | |
4588 | */ | |
4589 | void __sched io_schedule(void) | |
4590 | { | |
70b97a7f | 4591 | struct rq *rq = &__raw_get_cpu_var(runqueues); |
1da177e4 | 4592 | |
0ff92245 | 4593 | delayacct_blkio_start(); |
1da177e4 LT |
4594 | atomic_inc(&rq->nr_iowait); |
4595 | schedule(); | |
4596 | atomic_dec(&rq->nr_iowait); | |
0ff92245 | 4597 | delayacct_blkio_end(); |
1da177e4 | 4598 | } |
1da177e4 LT |
4599 | EXPORT_SYMBOL(io_schedule); |
4600 | ||
4601 | long __sched io_schedule_timeout(long timeout) | |
4602 | { | |
70b97a7f | 4603 | struct rq *rq = &__raw_get_cpu_var(runqueues); |
1da177e4 LT |
4604 | long ret; |
4605 | ||
0ff92245 | 4606 | delayacct_blkio_start(); |
1da177e4 LT |
4607 | atomic_inc(&rq->nr_iowait); |
4608 | ret = schedule_timeout(timeout); | |
4609 | atomic_dec(&rq->nr_iowait); | |
0ff92245 | 4610 | delayacct_blkio_end(); |
1da177e4 LT |
4611 | return ret; |
4612 | } | |
4613 | ||
4614 | /** | |
4615 | * sys_sched_get_priority_max - return maximum RT priority. | |
4616 | * @policy: scheduling class. | |
4617 | * | |
4618 | * this syscall returns the maximum rt_priority that can be used | |
4619 | * by a given scheduling class. | |
4620 | */ | |
4621 | asmlinkage long sys_sched_get_priority_max(int policy) | |
4622 | { | |
4623 | int ret = -EINVAL; | |
4624 | ||
4625 | switch (policy) { | |
4626 | case SCHED_FIFO: | |
4627 | case SCHED_RR: | |
4628 | ret = MAX_USER_RT_PRIO-1; | |
4629 | break; | |
4630 | case SCHED_NORMAL: | |
b0a9499c | 4631 | case SCHED_BATCH: |
dd41f596 | 4632 | case SCHED_IDLE: |
1da177e4 LT |
4633 | ret = 0; |
4634 | break; | |
4635 | } | |
4636 | return ret; | |
4637 | } | |
4638 | ||
4639 | /** | |
4640 | * sys_sched_get_priority_min - return minimum RT priority. | |
4641 | * @policy: scheduling class. | |
4642 | * | |
4643 | * this syscall returns the minimum rt_priority that can be used | |
4644 | * by a given scheduling class. | |
4645 | */ | |
4646 | asmlinkage long sys_sched_get_priority_min(int policy) | |
4647 | { | |
4648 | int ret = -EINVAL; | |
4649 | ||
4650 | switch (policy) { | |
4651 | case SCHED_FIFO: | |
4652 | case SCHED_RR: | |
4653 | ret = 1; | |
4654 | break; | |
4655 | case SCHED_NORMAL: | |
b0a9499c | 4656 | case SCHED_BATCH: |
dd41f596 | 4657 | case SCHED_IDLE: |
1da177e4 LT |
4658 | ret = 0; |
4659 | } | |
4660 | return ret; | |
4661 | } | |
4662 | ||
4663 | /** | |
4664 | * sys_sched_rr_get_interval - return the default timeslice of a process. | |
4665 | * @pid: pid of the process. | |
4666 | * @interval: userspace pointer to the timeslice value. | |
4667 | * | |
4668 | * this syscall writes the default timeslice value of a given process | |
4669 | * into the user-space timespec buffer. A value of '0' means infinity. | |
4670 | */ | |
4671 | asmlinkage | |
4672 | long sys_sched_rr_get_interval(pid_t pid, struct timespec __user *interval) | |
4673 | { | |
36c8b586 | 4674 | struct task_struct *p; |
1da177e4 LT |
4675 | int retval = -EINVAL; |
4676 | struct timespec t; | |
1da177e4 LT |
4677 | |
4678 | if (pid < 0) | |
4679 | goto out_nounlock; | |
4680 | ||
4681 | retval = -ESRCH; | |
4682 | read_lock(&tasklist_lock); | |
4683 | p = find_process_by_pid(pid); | |
4684 | if (!p) | |
4685 | goto out_unlock; | |
4686 | ||
4687 | retval = security_task_getscheduler(p); | |
4688 | if (retval) | |
4689 | goto out_unlock; | |
4690 | ||
b78709cf | 4691 | jiffies_to_timespec(p->policy == SCHED_FIFO ? |
dd41f596 | 4692 | 0 : static_prio_timeslice(p->static_prio), &t); |
1da177e4 LT |
4693 | read_unlock(&tasklist_lock); |
4694 | retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0; | |
4695 | out_nounlock: | |
4696 | return retval; | |
4697 | out_unlock: | |
4698 | read_unlock(&tasklist_lock); | |
4699 | return retval; | |
4700 | } | |
4701 | ||
2ed6e34f | 4702 | static const char stat_nam[] = "RSDTtZX"; |
36c8b586 IM |
4703 | |
4704 | static void show_task(struct task_struct *p) | |
1da177e4 | 4705 | { |
1da177e4 | 4706 | unsigned long free = 0; |
36c8b586 | 4707 | unsigned state; |
1da177e4 | 4708 | |
1da177e4 | 4709 | state = p->state ? __ffs(p->state) + 1 : 0; |
2ed6e34f AM |
4710 | printk("%-13.13s %c", p->comm, |
4711 | state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?'); | |
1da177e4 LT |
4712 | #if (BITS_PER_LONG == 32) |
4713 | if (state == TASK_RUNNING) | |
4714 | printk(" running "); | |
4715 | else | |
4716 | printk(" %08lX ", thread_saved_pc(p)); | |
4717 | #else | |
4718 | if (state == TASK_RUNNING) | |
4719 | printk(" running task "); | |
4720 | else | |
4721 | printk(" %016lx ", thread_saved_pc(p)); | |
4722 | #endif | |
4723 | #ifdef CONFIG_DEBUG_STACK_USAGE | |
4724 | { | |
10ebffde | 4725 | unsigned long *n = end_of_stack(p); |
1da177e4 LT |
4726 | while (!*n) |
4727 | n++; | |
10ebffde | 4728 | free = (unsigned long)n - (unsigned long)end_of_stack(p); |
1da177e4 LT |
4729 | } |
4730 | #endif | |
35f6f753 | 4731 | printk("%5lu %5d %6d", free, p->pid, p->parent->pid); |
1da177e4 LT |
4732 | if (!p->mm) |
4733 | printk(" (L-TLB)\n"); | |
4734 | else | |
4735 | printk(" (NOTLB)\n"); | |
4736 | ||
4737 | if (state != TASK_RUNNING) | |
4738 | show_stack(p, NULL); | |
4739 | } | |
4740 | ||
e59e2ae2 | 4741 | void show_state_filter(unsigned long state_filter) |
1da177e4 | 4742 | { |
36c8b586 | 4743 | struct task_struct *g, *p; |
1da177e4 LT |
4744 | |
4745 | #if (BITS_PER_LONG == 32) | |
4746 | printk("\n" | |
301827ac CC |
4747 | " free sibling\n"); |
4748 | printk(" task PC stack pid father child younger older\n"); | |
1da177e4 LT |
4749 | #else |
4750 | printk("\n" | |
301827ac CC |
4751 | " free sibling\n"); |
4752 | printk(" task PC stack pid father child younger older\n"); | |
1da177e4 LT |
4753 | #endif |
4754 | read_lock(&tasklist_lock); | |
4755 | do_each_thread(g, p) { | |
4756 | /* | |
4757 | * reset the NMI-timeout, listing all files on a slow | |
4758 | * console might take alot of time: | |
4759 | */ | |
4760 | touch_nmi_watchdog(); | |
39bc89fd | 4761 | if (!state_filter || (p->state & state_filter)) |
e59e2ae2 | 4762 | show_task(p); |
1da177e4 LT |
4763 | } while_each_thread(g, p); |
4764 | ||
04c9167f JF |
4765 | touch_all_softlockup_watchdogs(); |
4766 | ||
dd41f596 IM |
4767 | #ifdef CONFIG_SCHED_DEBUG |
4768 | sysrq_sched_debug_show(); | |
4769 | #endif | |
1da177e4 | 4770 | read_unlock(&tasklist_lock); |
e59e2ae2 IM |
4771 | /* |
4772 | * Only show locks if all tasks are dumped: | |
4773 | */ | |
4774 | if (state_filter == -1) | |
4775 | debug_show_all_locks(); | |
1da177e4 LT |
4776 | } |
4777 | ||
1df21055 IM |
4778 | void __cpuinit init_idle_bootup_task(struct task_struct *idle) |
4779 | { | |
dd41f596 | 4780 | idle->sched_class = &idle_sched_class; |
1df21055 IM |
4781 | } |
4782 | ||
f340c0d1 IM |
4783 | /** |
4784 | * init_idle - set up an idle thread for a given CPU | |
4785 | * @idle: task in question | |
4786 | * @cpu: cpu the idle task belongs to | |
4787 | * | |
4788 | * NOTE: this function does not set the idle thread's NEED_RESCHED | |
4789 | * flag, to make booting more robust. | |
4790 | */ | |
5c1e1767 | 4791 | void __cpuinit init_idle(struct task_struct *idle, int cpu) |
1da177e4 | 4792 | { |
70b97a7f | 4793 | struct rq *rq = cpu_rq(cpu); |
1da177e4 LT |
4794 | unsigned long flags; |
4795 | ||
dd41f596 IM |
4796 | __sched_fork(idle); |
4797 | idle->se.exec_start = sched_clock(); | |
4798 | ||
b29739f9 | 4799 | idle->prio = idle->normal_prio = MAX_PRIO; |
1da177e4 | 4800 | idle->cpus_allowed = cpumask_of_cpu(cpu); |
dd41f596 | 4801 | __set_task_cpu(idle, cpu); |
1da177e4 LT |
4802 | |
4803 | spin_lock_irqsave(&rq->lock, flags); | |
4804 | rq->curr = rq->idle = idle; | |
4866cde0 NP |
4805 | #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW) |
4806 | idle->oncpu = 1; | |
4807 | #endif | |
1da177e4 LT |
4808 | spin_unlock_irqrestore(&rq->lock, flags); |
4809 | ||
4810 | /* Set the preempt count _outside_ the spinlocks! */ | |
4811 | #if defined(CONFIG_PREEMPT) && !defined(CONFIG_PREEMPT_BKL) | |
a1261f54 | 4812 | task_thread_info(idle)->preempt_count = (idle->lock_depth >= 0); |
1da177e4 | 4813 | #else |
a1261f54 | 4814 | task_thread_info(idle)->preempt_count = 0; |
1da177e4 | 4815 | #endif |
dd41f596 IM |
4816 | /* |
4817 | * The idle tasks have their own, simple scheduling class: | |
4818 | */ | |
4819 | idle->sched_class = &idle_sched_class; | |
1da177e4 LT |
4820 | } |
4821 | ||
4822 | /* | |
4823 | * In a system that switches off the HZ timer nohz_cpu_mask | |
4824 | * indicates which cpus entered this state. This is used | |
4825 | * in the rcu update to wait only for active cpus. For system | |
4826 | * which do not switch off the HZ timer nohz_cpu_mask should | |
4827 | * always be CPU_MASK_NONE. | |
4828 | */ | |
4829 | cpumask_t nohz_cpu_mask = CPU_MASK_NONE; | |
4830 | ||
dd41f596 IM |
4831 | /* |
4832 | * Increase the granularity value when there are more CPUs, | |
4833 | * because with more CPUs the 'effective latency' as visible | |
4834 | * to users decreases. But the relationship is not linear, | |
4835 | * so pick a second-best guess by going with the log2 of the | |
4836 | * number of CPUs. | |
4837 | * | |
4838 | * This idea comes from the SD scheduler of Con Kolivas: | |
4839 | */ | |
4840 | static inline void sched_init_granularity(void) | |
4841 | { | |
4842 | unsigned int factor = 1 + ilog2(num_online_cpus()); | |
4843 | const unsigned long gran_limit = 10000000; | |
4844 | ||
4845 | sysctl_sched_granularity *= factor; | |
4846 | if (sysctl_sched_granularity > gran_limit) | |
4847 | sysctl_sched_granularity = gran_limit; | |
4848 | ||
4849 | sysctl_sched_runtime_limit = sysctl_sched_granularity * 4; | |
4850 | sysctl_sched_wakeup_granularity = sysctl_sched_granularity / 2; | |
4851 | } | |
4852 | ||
1da177e4 LT |
4853 | #ifdef CONFIG_SMP |
4854 | /* | |
4855 | * This is how migration works: | |
4856 | * | |
70b97a7f | 4857 | * 1) we queue a struct migration_req structure in the source CPU's |
1da177e4 LT |
4858 | * runqueue and wake up that CPU's migration thread. |
4859 | * 2) we down() the locked semaphore => thread blocks. | |
4860 | * 3) migration thread wakes up (implicitly it forces the migrated | |
4861 | * thread off the CPU) | |
4862 | * 4) it gets the migration request and checks whether the migrated | |
4863 | * task is still in the wrong runqueue. | |
4864 | * 5) if it's in the wrong runqueue then the migration thread removes | |
4865 | * it and puts it into the right queue. | |
4866 | * 6) migration thread up()s the semaphore. | |
4867 | * 7) we wake up and the migration is done. | |
4868 | */ | |
4869 | ||
4870 | /* | |
4871 | * Change a given task's CPU affinity. Migrate the thread to a | |
4872 | * proper CPU and schedule it away if the CPU it's executing on | |
4873 | * is removed from the allowed bitmask. | |
4874 | * | |
4875 | * NOTE: the caller must have a valid reference to the task, the | |
4876 | * task must not exit() & deallocate itself prematurely. The | |
4877 | * call is not atomic; no spinlocks may be held. | |
4878 | */ | |
36c8b586 | 4879 | int set_cpus_allowed(struct task_struct *p, cpumask_t new_mask) |
1da177e4 | 4880 | { |
70b97a7f | 4881 | struct migration_req req; |
1da177e4 | 4882 | unsigned long flags; |
70b97a7f | 4883 | struct rq *rq; |
48f24c4d | 4884 | int ret = 0; |
1da177e4 LT |
4885 | |
4886 | rq = task_rq_lock(p, &flags); | |
4887 | if (!cpus_intersects(new_mask, cpu_online_map)) { | |
4888 | ret = -EINVAL; | |
4889 | goto out; | |
4890 | } | |
4891 | ||
4892 | p->cpus_allowed = new_mask; | |
4893 | /* Can the task run on the task's current CPU? If so, we're done */ | |
4894 | if (cpu_isset(task_cpu(p), new_mask)) | |
4895 | goto out; | |
4896 | ||
4897 | if (migrate_task(p, any_online_cpu(new_mask), &req)) { | |
4898 | /* Need help from migration thread: drop lock and wait. */ | |
4899 | task_rq_unlock(rq, &flags); | |
4900 | wake_up_process(rq->migration_thread); | |
4901 | wait_for_completion(&req.done); | |
4902 | tlb_migrate_finish(p->mm); | |
4903 | return 0; | |
4904 | } | |
4905 | out: | |
4906 | task_rq_unlock(rq, &flags); | |
48f24c4d | 4907 | |
1da177e4 LT |
4908 | return ret; |
4909 | } | |
1da177e4 LT |
4910 | EXPORT_SYMBOL_GPL(set_cpus_allowed); |
4911 | ||
4912 | /* | |
4913 | * Move (not current) task off this cpu, onto dest cpu. We're doing | |
4914 | * this because either it can't run here any more (set_cpus_allowed() | |
4915 | * away from this CPU, or CPU going down), or because we're | |
4916 | * attempting to rebalance this task on exec (sched_exec). | |
4917 | * | |
4918 | * So we race with normal scheduler movements, but that's OK, as long | |
4919 | * as the task is no longer on this CPU. | |
efc30814 KK |
4920 | * |
4921 | * Returns non-zero if task was successfully migrated. | |
1da177e4 | 4922 | */ |
efc30814 | 4923 | static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu) |
1da177e4 | 4924 | { |
70b97a7f | 4925 | struct rq *rq_dest, *rq_src; |
dd41f596 | 4926 | int ret = 0, on_rq; |
1da177e4 LT |
4927 | |
4928 | if (unlikely(cpu_is_offline(dest_cpu))) | |
efc30814 | 4929 | return ret; |
1da177e4 LT |
4930 | |
4931 | rq_src = cpu_rq(src_cpu); | |
4932 | rq_dest = cpu_rq(dest_cpu); | |
4933 | ||
4934 | double_rq_lock(rq_src, rq_dest); | |
4935 | /* Already moved. */ | |
4936 | if (task_cpu(p) != src_cpu) | |
4937 | goto out; | |
4938 | /* Affinity changed (again). */ | |
4939 | if (!cpu_isset(dest_cpu, p->cpus_allowed)) | |
4940 | goto out; | |
4941 | ||
dd41f596 IM |
4942 | on_rq = p->se.on_rq; |
4943 | if (on_rq) | |
4944 | deactivate_task(rq_src, p, 0); | |
1da177e4 | 4945 | set_task_cpu(p, dest_cpu); |
dd41f596 IM |
4946 | if (on_rq) { |
4947 | activate_task(rq_dest, p, 0); | |
4948 | check_preempt_curr(rq_dest, p); | |
1da177e4 | 4949 | } |
efc30814 | 4950 | ret = 1; |
1da177e4 LT |
4951 | out: |
4952 | double_rq_unlock(rq_src, rq_dest); | |
efc30814 | 4953 | return ret; |
1da177e4 LT |
4954 | } |
4955 | ||
4956 | /* | |
4957 | * migration_thread - this is a highprio system thread that performs | |
4958 | * thread migration by bumping thread off CPU then 'pushing' onto | |
4959 | * another runqueue. | |
4960 | */ | |
95cdf3b7 | 4961 | static int migration_thread(void *data) |
1da177e4 | 4962 | { |
1da177e4 | 4963 | int cpu = (long)data; |
70b97a7f | 4964 | struct rq *rq; |
1da177e4 LT |
4965 | |
4966 | rq = cpu_rq(cpu); | |
4967 | BUG_ON(rq->migration_thread != current); | |
4968 | ||
4969 | set_current_state(TASK_INTERRUPTIBLE); | |
4970 | while (!kthread_should_stop()) { | |
70b97a7f | 4971 | struct migration_req *req; |
1da177e4 | 4972 | struct list_head *head; |
1da177e4 | 4973 | |
3e1d1d28 | 4974 | try_to_freeze(); |
1da177e4 LT |
4975 | |
4976 | spin_lock_irq(&rq->lock); | |
4977 | ||
4978 | if (cpu_is_offline(cpu)) { | |
4979 | spin_unlock_irq(&rq->lock); | |
4980 | goto wait_to_die; | |
4981 | } | |
4982 | ||
4983 | if (rq->active_balance) { | |
4984 | active_load_balance(rq, cpu); | |
4985 | rq->active_balance = 0; | |
4986 | } | |
4987 | ||
4988 | head = &rq->migration_queue; | |
4989 | ||
4990 | if (list_empty(head)) { | |
4991 | spin_unlock_irq(&rq->lock); | |
4992 | schedule(); | |
4993 | set_current_state(TASK_INTERRUPTIBLE); | |
4994 | continue; | |
4995 | } | |
70b97a7f | 4996 | req = list_entry(head->next, struct migration_req, list); |
1da177e4 LT |
4997 | list_del_init(head->next); |
4998 | ||
674311d5 NP |
4999 | spin_unlock(&rq->lock); |
5000 | __migrate_task(req->task, cpu, req->dest_cpu); | |
5001 | local_irq_enable(); | |
1da177e4 LT |
5002 | |
5003 | complete(&req->done); | |
5004 | } | |
5005 | __set_current_state(TASK_RUNNING); | |
5006 | return 0; | |
5007 | ||
5008 | wait_to_die: | |
5009 | /* Wait for kthread_stop */ | |
5010 | set_current_state(TASK_INTERRUPTIBLE); | |
5011 | while (!kthread_should_stop()) { | |
5012 | schedule(); | |
5013 | set_current_state(TASK_INTERRUPTIBLE); | |
5014 | } | |
5015 | __set_current_state(TASK_RUNNING); | |
5016 | return 0; | |
5017 | } | |
5018 | ||
5019 | #ifdef CONFIG_HOTPLUG_CPU | |
054b9108 KK |
5020 | /* |
5021 | * Figure out where task on dead CPU should go, use force if neccessary. | |
5022 | * NOTE: interrupts should be disabled by the caller | |
5023 | */ | |
48f24c4d | 5024 | static void move_task_off_dead_cpu(int dead_cpu, struct task_struct *p) |
1da177e4 | 5025 | { |
efc30814 | 5026 | unsigned long flags; |
1da177e4 | 5027 | cpumask_t mask; |
70b97a7f IM |
5028 | struct rq *rq; |
5029 | int dest_cpu; | |
1da177e4 | 5030 | |
efc30814 | 5031 | restart: |
1da177e4 LT |
5032 | /* On same node? */ |
5033 | mask = node_to_cpumask(cpu_to_node(dead_cpu)); | |
48f24c4d | 5034 | cpus_and(mask, mask, p->cpus_allowed); |
1da177e4 LT |
5035 | dest_cpu = any_online_cpu(mask); |
5036 | ||
5037 | /* On any allowed CPU? */ | |
5038 | if (dest_cpu == NR_CPUS) | |
48f24c4d | 5039 | dest_cpu = any_online_cpu(p->cpus_allowed); |
1da177e4 LT |
5040 | |
5041 | /* No more Mr. Nice Guy. */ | |
5042 | if (dest_cpu == NR_CPUS) { | |
48f24c4d IM |
5043 | rq = task_rq_lock(p, &flags); |
5044 | cpus_setall(p->cpus_allowed); | |
5045 | dest_cpu = any_online_cpu(p->cpus_allowed); | |
efc30814 | 5046 | task_rq_unlock(rq, &flags); |
1da177e4 LT |
5047 | |
5048 | /* | |
5049 | * Don't tell them about moving exiting tasks or | |
5050 | * kernel threads (both mm NULL), since they never | |
5051 | * leave kernel. | |
5052 | */ | |
48f24c4d | 5053 | if (p->mm && printk_ratelimit()) |
1da177e4 LT |
5054 | printk(KERN_INFO "process %d (%s) no " |
5055 | "longer affine to cpu%d\n", | |
48f24c4d | 5056 | p->pid, p->comm, dead_cpu); |
1da177e4 | 5057 | } |
48f24c4d | 5058 | if (!__migrate_task(p, dead_cpu, dest_cpu)) |
efc30814 | 5059 | goto restart; |
1da177e4 LT |
5060 | } |
5061 | ||
5062 | /* | |
5063 | * While a dead CPU has no uninterruptible tasks queued at this point, | |
5064 | * it might still have a nonzero ->nr_uninterruptible counter, because | |
5065 | * for performance reasons the counter is not stricly tracking tasks to | |
5066 | * their home CPUs. So we just add the counter to another CPU's counter, | |
5067 | * to keep the global sum constant after CPU-down: | |
5068 | */ | |
70b97a7f | 5069 | static void migrate_nr_uninterruptible(struct rq *rq_src) |
1da177e4 | 5070 | { |
70b97a7f | 5071 | struct rq *rq_dest = cpu_rq(any_online_cpu(CPU_MASK_ALL)); |
1da177e4 LT |
5072 | unsigned long flags; |
5073 | ||
5074 | local_irq_save(flags); | |
5075 | double_rq_lock(rq_src, rq_dest); | |
5076 | rq_dest->nr_uninterruptible += rq_src->nr_uninterruptible; | |
5077 | rq_src->nr_uninterruptible = 0; | |
5078 | double_rq_unlock(rq_src, rq_dest); | |
5079 | local_irq_restore(flags); | |
5080 | } | |
5081 | ||
5082 | /* Run through task list and migrate tasks from the dead cpu. */ | |
5083 | static void migrate_live_tasks(int src_cpu) | |
5084 | { | |
48f24c4d | 5085 | struct task_struct *p, *t; |
1da177e4 LT |
5086 | |
5087 | write_lock_irq(&tasklist_lock); | |
5088 | ||
48f24c4d IM |
5089 | do_each_thread(t, p) { |
5090 | if (p == current) | |
1da177e4 LT |
5091 | continue; |
5092 | ||
48f24c4d IM |
5093 | if (task_cpu(p) == src_cpu) |
5094 | move_task_off_dead_cpu(src_cpu, p); | |
5095 | } while_each_thread(t, p); | |
1da177e4 LT |
5096 | |
5097 | write_unlock_irq(&tasklist_lock); | |
5098 | } | |
5099 | ||
dd41f596 IM |
5100 | /* |
5101 | * Schedules idle task to be the next runnable task on current CPU. | |
1da177e4 | 5102 | * It does so by boosting its priority to highest possible and adding it to |
48f24c4d | 5103 | * the _front_ of the runqueue. Used by CPU offline code. |
1da177e4 LT |
5104 | */ |
5105 | void sched_idle_next(void) | |
5106 | { | |
48f24c4d | 5107 | int this_cpu = smp_processor_id(); |
70b97a7f | 5108 | struct rq *rq = cpu_rq(this_cpu); |
1da177e4 LT |
5109 | struct task_struct *p = rq->idle; |
5110 | unsigned long flags; | |
5111 | ||
5112 | /* cpu has to be offline */ | |
48f24c4d | 5113 | BUG_ON(cpu_online(this_cpu)); |
1da177e4 | 5114 | |
48f24c4d IM |
5115 | /* |
5116 | * Strictly not necessary since rest of the CPUs are stopped by now | |
5117 | * and interrupts disabled on the current cpu. | |
1da177e4 LT |
5118 | */ |
5119 | spin_lock_irqsave(&rq->lock, flags); | |
5120 | ||
dd41f596 | 5121 | __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1); |
48f24c4d IM |
5122 | |
5123 | /* Add idle task to the _front_ of its priority queue: */ | |
dd41f596 | 5124 | activate_idle_task(p, rq); |
1da177e4 LT |
5125 | |
5126 | spin_unlock_irqrestore(&rq->lock, flags); | |
5127 | } | |
5128 | ||
48f24c4d IM |
5129 | /* |
5130 | * Ensures that the idle task is using init_mm right before its cpu goes | |
1da177e4 LT |
5131 | * offline. |
5132 | */ | |
5133 | void idle_task_exit(void) | |
5134 | { | |
5135 | struct mm_struct *mm = current->active_mm; | |
5136 | ||
5137 | BUG_ON(cpu_online(smp_processor_id())); | |
5138 | ||
5139 | if (mm != &init_mm) | |
5140 | switch_mm(mm, &init_mm, current); | |
5141 | mmdrop(mm); | |
5142 | } | |
5143 | ||
054b9108 | 5144 | /* called under rq->lock with disabled interrupts */ |
36c8b586 | 5145 | static void migrate_dead(unsigned int dead_cpu, struct task_struct *p) |
1da177e4 | 5146 | { |
70b97a7f | 5147 | struct rq *rq = cpu_rq(dead_cpu); |
1da177e4 LT |
5148 | |
5149 | /* Must be exiting, otherwise would be on tasklist. */ | |
48f24c4d | 5150 | BUG_ON(p->exit_state != EXIT_ZOMBIE && p->exit_state != EXIT_DEAD); |
1da177e4 LT |
5151 | |
5152 | /* Cannot have done final schedule yet: would have vanished. */ | |
c394cc9f | 5153 | BUG_ON(p->state == TASK_DEAD); |
1da177e4 | 5154 | |
48f24c4d | 5155 | get_task_struct(p); |
1da177e4 LT |
5156 | |
5157 | /* | |
5158 | * Drop lock around migration; if someone else moves it, | |
5159 | * that's OK. No task can be added to this CPU, so iteration is | |
5160 | * fine. | |
054b9108 | 5161 | * NOTE: interrupts should be left disabled --dev@ |
1da177e4 | 5162 | */ |
054b9108 | 5163 | spin_unlock(&rq->lock); |
48f24c4d | 5164 | move_task_off_dead_cpu(dead_cpu, p); |
054b9108 | 5165 | spin_lock(&rq->lock); |
1da177e4 | 5166 | |
48f24c4d | 5167 | put_task_struct(p); |
1da177e4 LT |
5168 | } |
5169 | ||
5170 | /* release_task() removes task from tasklist, so we won't find dead tasks. */ | |
5171 | static void migrate_dead_tasks(unsigned int dead_cpu) | |
5172 | { | |
70b97a7f | 5173 | struct rq *rq = cpu_rq(dead_cpu); |
dd41f596 | 5174 | struct task_struct *next; |
48f24c4d | 5175 | |
dd41f596 IM |
5176 | for ( ; ; ) { |
5177 | if (!rq->nr_running) | |
5178 | break; | |
5179 | next = pick_next_task(rq, rq->curr, rq_clock(rq)); | |
5180 | if (!next) | |
5181 | break; | |
5182 | migrate_dead(dead_cpu, next); | |
1da177e4 LT |
5183 | } |
5184 | } | |
5185 | #endif /* CONFIG_HOTPLUG_CPU */ | |
5186 | ||
5187 | /* | |
5188 | * migration_call - callback that gets triggered when a CPU is added. | |
5189 | * Here we can start up the necessary migration thread for the new CPU. | |
5190 | */ | |
48f24c4d IM |
5191 | static int __cpuinit |
5192 | migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) | |
1da177e4 | 5193 | { |
1da177e4 | 5194 | struct task_struct *p; |
48f24c4d | 5195 | int cpu = (long)hcpu; |
1da177e4 | 5196 | unsigned long flags; |
70b97a7f | 5197 | struct rq *rq; |
1da177e4 LT |
5198 | |
5199 | switch (action) { | |
5be9361c GS |
5200 | case CPU_LOCK_ACQUIRE: |
5201 | mutex_lock(&sched_hotcpu_mutex); | |
5202 | break; | |
5203 | ||
1da177e4 | 5204 | case CPU_UP_PREPARE: |
8bb78442 | 5205 | case CPU_UP_PREPARE_FROZEN: |
dd41f596 | 5206 | p = kthread_create(migration_thread, hcpu, "migration/%d", cpu); |
1da177e4 LT |
5207 | if (IS_ERR(p)) |
5208 | return NOTIFY_BAD; | |
5209 | p->flags |= PF_NOFREEZE; | |
5210 | kthread_bind(p, cpu); | |
5211 | /* Must be high prio: stop_machine expects to yield to it. */ | |
5212 | rq = task_rq_lock(p, &flags); | |
dd41f596 | 5213 | __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1); |
1da177e4 LT |
5214 | task_rq_unlock(rq, &flags); |
5215 | cpu_rq(cpu)->migration_thread = p; | |
5216 | break; | |
48f24c4d | 5217 | |
1da177e4 | 5218 | case CPU_ONLINE: |
8bb78442 | 5219 | case CPU_ONLINE_FROZEN: |
1da177e4 LT |
5220 | /* Strictly unneccessary, as first user will wake it. */ |
5221 | wake_up_process(cpu_rq(cpu)->migration_thread); | |
5222 | break; | |
48f24c4d | 5223 | |
1da177e4 LT |
5224 | #ifdef CONFIG_HOTPLUG_CPU |
5225 | case CPU_UP_CANCELED: | |
8bb78442 | 5226 | case CPU_UP_CANCELED_FROZEN: |
fc75cdfa HC |
5227 | if (!cpu_rq(cpu)->migration_thread) |
5228 | break; | |
1da177e4 | 5229 | /* Unbind it from offline cpu so it can run. Fall thru. */ |
a4c4af7c HC |
5230 | kthread_bind(cpu_rq(cpu)->migration_thread, |
5231 | any_online_cpu(cpu_online_map)); | |
1da177e4 LT |
5232 | kthread_stop(cpu_rq(cpu)->migration_thread); |
5233 | cpu_rq(cpu)->migration_thread = NULL; | |
5234 | break; | |
48f24c4d | 5235 | |
1da177e4 | 5236 | case CPU_DEAD: |
8bb78442 | 5237 | case CPU_DEAD_FROZEN: |
1da177e4 LT |
5238 | migrate_live_tasks(cpu); |
5239 | rq = cpu_rq(cpu); | |
5240 | kthread_stop(rq->migration_thread); | |
5241 | rq->migration_thread = NULL; | |
5242 | /* Idle task back to normal (off runqueue, low prio) */ | |
5243 | rq = task_rq_lock(rq->idle, &flags); | |
dd41f596 | 5244 | deactivate_task(rq, rq->idle, 0); |
1da177e4 | 5245 | rq->idle->static_prio = MAX_PRIO; |
dd41f596 IM |
5246 | __setscheduler(rq, rq->idle, SCHED_NORMAL, 0); |
5247 | rq->idle->sched_class = &idle_sched_class; | |
1da177e4 LT |
5248 | migrate_dead_tasks(cpu); |
5249 | task_rq_unlock(rq, &flags); | |
5250 | migrate_nr_uninterruptible(rq); | |
5251 | BUG_ON(rq->nr_running != 0); | |
5252 | ||
5253 | /* No need to migrate the tasks: it was best-effort if | |
5be9361c | 5254 | * they didn't take sched_hotcpu_mutex. Just wake up |
1da177e4 LT |
5255 | * the requestors. */ |
5256 | spin_lock_irq(&rq->lock); | |
5257 | while (!list_empty(&rq->migration_queue)) { | |
70b97a7f IM |
5258 | struct migration_req *req; |
5259 | ||
1da177e4 | 5260 | req = list_entry(rq->migration_queue.next, |
70b97a7f | 5261 | struct migration_req, list); |
1da177e4 LT |
5262 | list_del_init(&req->list); |
5263 | complete(&req->done); | |
5264 | } | |
5265 | spin_unlock_irq(&rq->lock); | |
5266 | break; | |
5267 | #endif | |
5be9361c GS |
5268 | case CPU_LOCK_RELEASE: |
5269 | mutex_unlock(&sched_hotcpu_mutex); | |
5270 | break; | |
1da177e4 LT |
5271 | } |
5272 | return NOTIFY_OK; | |
5273 | } | |
5274 | ||
5275 | /* Register at highest priority so that task migration (migrate_all_tasks) | |
5276 | * happens before everything else. | |
5277 | */ | |
26c2143b | 5278 | static struct notifier_block __cpuinitdata migration_notifier = { |
1da177e4 LT |
5279 | .notifier_call = migration_call, |
5280 | .priority = 10 | |
5281 | }; | |
5282 | ||
5283 | int __init migration_init(void) | |
5284 | { | |
5285 | void *cpu = (void *)(long)smp_processor_id(); | |
07dccf33 | 5286 | int err; |
48f24c4d IM |
5287 | |
5288 | /* Start one for the boot CPU: */ | |
07dccf33 AM |
5289 | err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu); |
5290 | BUG_ON(err == NOTIFY_BAD); | |
1da177e4 LT |
5291 | migration_call(&migration_notifier, CPU_ONLINE, cpu); |
5292 | register_cpu_notifier(&migration_notifier); | |
48f24c4d | 5293 | |
1da177e4 LT |
5294 | return 0; |
5295 | } | |
5296 | #endif | |
5297 | ||
5298 | #ifdef CONFIG_SMP | |
476f3534 CL |
5299 | |
5300 | /* Number of possible processor ids */ | |
5301 | int nr_cpu_ids __read_mostly = NR_CPUS; | |
5302 | EXPORT_SYMBOL(nr_cpu_ids); | |
5303 | ||
1a20ff27 | 5304 | #undef SCHED_DOMAIN_DEBUG |
1da177e4 LT |
5305 | #ifdef SCHED_DOMAIN_DEBUG |
5306 | static void sched_domain_debug(struct sched_domain *sd, int cpu) | |
5307 | { | |
5308 | int level = 0; | |
5309 | ||
41c7ce9a NP |
5310 | if (!sd) { |
5311 | printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu); | |
5312 | return; | |
5313 | } | |
5314 | ||
1da177e4 LT |
5315 | printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu); |
5316 | ||
5317 | do { | |
5318 | int i; | |
5319 | char str[NR_CPUS]; | |
5320 | struct sched_group *group = sd->groups; | |
5321 | cpumask_t groupmask; | |
5322 | ||
5323 | cpumask_scnprintf(str, NR_CPUS, sd->span); | |
5324 | cpus_clear(groupmask); | |
5325 | ||
5326 | printk(KERN_DEBUG); | |
5327 | for (i = 0; i < level + 1; i++) | |
5328 | printk(" "); | |
5329 | printk("domain %d: ", level); | |
5330 | ||
5331 | if (!(sd->flags & SD_LOAD_BALANCE)) { | |
5332 | printk("does not load-balance\n"); | |
5333 | if (sd->parent) | |
33859f7f MOS |
5334 | printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain" |
5335 | " has parent"); | |
1da177e4 LT |
5336 | break; |
5337 | } | |
5338 | ||
5339 | printk("span %s\n", str); | |
5340 | ||
5341 | if (!cpu_isset(cpu, sd->span)) | |
33859f7f MOS |
5342 | printk(KERN_ERR "ERROR: domain->span does not contain " |
5343 | "CPU%d\n", cpu); | |
1da177e4 | 5344 | if (!cpu_isset(cpu, group->cpumask)) |
33859f7f MOS |
5345 | printk(KERN_ERR "ERROR: domain->groups does not contain" |
5346 | " CPU%d\n", cpu); | |
1da177e4 LT |
5347 | |
5348 | printk(KERN_DEBUG); | |
5349 | for (i = 0; i < level + 2; i++) | |
5350 | printk(" "); | |
5351 | printk("groups:"); | |
5352 | do { | |
5353 | if (!group) { | |
5354 | printk("\n"); | |
5355 | printk(KERN_ERR "ERROR: group is NULL\n"); | |
5356 | break; | |
5357 | } | |
5358 | ||
5517d86b | 5359 | if (!group->__cpu_power) { |
1da177e4 | 5360 | printk("\n"); |
33859f7f MOS |
5361 | printk(KERN_ERR "ERROR: domain->cpu_power not " |
5362 | "set\n"); | |
1da177e4 LT |
5363 | } |
5364 | ||
5365 | if (!cpus_weight(group->cpumask)) { | |
5366 | printk("\n"); | |
5367 | printk(KERN_ERR "ERROR: empty group\n"); | |
5368 | } | |
5369 | ||
5370 | if (cpus_intersects(groupmask, group->cpumask)) { | |
5371 | printk("\n"); | |
5372 | printk(KERN_ERR "ERROR: repeated CPUs\n"); | |
5373 | } | |
5374 | ||
5375 | cpus_or(groupmask, groupmask, group->cpumask); | |
5376 | ||
5377 | cpumask_scnprintf(str, NR_CPUS, group->cpumask); | |
5378 | printk(" %s", str); | |
5379 | ||
5380 | group = group->next; | |
5381 | } while (group != sd->groups); | |
5382 | printk("\n"); | |
5383 | ||
5384 | if (!cpus_equal(sd->span, groupmask)) | |
33859f7f MOS |
5385 | printk(KERN_ERR "ERROR: groups don't span " |
5386 | "domain->span\n"); | |
1da177e4 LT |
5387 | |
5388 | level++; | |
5389 | sd = sd->parent; | |
33859f7f MOS |
5390 | if (!sd) |
5391 | continue; | |
1da177e4 | 5392 | |
33859f7f MOS |
5393 | if (!cpus_subset(groupmask, sd->span)) |
5394 | printk(KERN_ERR "ERROR: parent span is not a superset " | |
5395 | "of domain->span\n"); | |
1da177e4 LT |
5396 | |
5397 | } while (sd); | |
5398 | } | |
5399 | #else | |
48f24c4d | 5400 | # define sched_domain_debug(sd, cpu) do { } while (0) |
1da177e4 LT |
5401 | #endif |
5402 | ||
1a20ff27 | 5403 | static int sd_degenerate(struct sched_domain *sd) |
245af2c7 SS |
5404 | { |
5405 | if (cpus_weight(sd->span) == 1) | |
5406 | return 1; | |
5407 | ||
5408 | /* Following flags need at least 2 groups */ | |
5409 | if (sd->flags & (SD_LOAD_BALANCE | | |
5410 | SD_BALANCE_NEWIDLE | | |
5411 | SD_BALANCE_FORK | | |
89c4710e SS |
5412 | SD_BALANCE_EXEC | |
5413 | SD_SHARE_CPUPOWER | | |
5414 | SD_SHARE_PKG_RESOURCES)) { | |
245af2c7 SS |
5415 | if (sd->groups != sd->groups->next) |
5416 | return 0; | |
5417 | } | |
5418 | ||
5419 | /* Following flags don't use groups */ | |
5420 | if (sd->flags & (SD_WAKE_IDLE | | |
5421 | SD_WAKE_AFFINE | | |
5422 | SD_WAKE_BALANCE)) | |
5423 | return 0; | |
5424 | ||
5425 | return 1; | |
5426 | } | |
5427 | ||
48f24c4d IM |
5428 | static int |
5429 | sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent) | |
245af2c7 SS |
5430 | { |
5431 | unsigned long cflags = sd->flags, pflags = parent->flags; | |
5432 | ||
5433 | if (sd_degenerate(parent)) | |
5434 | return 1; | |
5435 | ||
5436 | if (!cpus_equal(sd->span, parent->span)) | |
5437 | return 0; | |
5438 | ||
5439 | /* Does parent contain flags not in child? */ | |
5440 | /* WAKE_BALANCE is a subset of WAKE_AFFINE */ | |
5441 | if (cflags & SD_WAKE_AFFINE) | |
5442 | pflags &= ~SD_WAKE_BALANCE; | |
5443 | /* Flags needing groups don't count if only 1 group in parent */ | |
5444 | if (parent->groups == parent->groups->next) { | |
5445 | pflags &= ~(SD_LOAD_BALANCE | | |
5446 | SD_BALANCE_NEWIDLE | | |
5447 | SD_BALANCE_FORK | | |
89c4710e SS |
5448 | SD_BALANCE_EXEC | |
5449 | SD_SHARE_CPUPOWER | | |
5450 | SD_SHARE_PKG_RESOURCES); | |
245af2c7 SS |
5451 | } |
5452 | if (~cflags & pflags) | |
5453 | return 0; | |
5454 | ||
5455 | return 1; | |
5456 | } | |
5457 | ||
1da177e4 LT |
5458 | /* |
5459 | * Attach the domain 'sd' to 'cpu' as its base domain. Callers must | |
5460 | * hold the hotplug lock. | |
5461 | */ | |
9c1cfda2 | 5462 | static void cpu_attach_domain(struct sched_domain *sd, int cpu) |
1da177e4 | 5463 | { |
70b97a7f | 5464 | struct rq *rq = cpu_rq(cpu); |
245af2c7 SS |
5465 | struct sched_domain *tmp; |
5466 | ||
5467 | /* Remove the sched domains which do not contribute to scheduling. */ | |
5468 | for (tmp = sd; tmp; tmp = tmp->parent) { | |
5469 | struct sched_domain *parent = tmp->parent; | |
5470 | if (!parent) | |
5471 | break; | |
1a848870 | 5472 | if (sd_parent_degenerate(tmp, parent)) { |
245af2c7 | 5473 | tmp->parent = parent->parent; |
1a848870 SS |
5474 | if (parent->parent) |
5475 | parent->parent->child = tmp; | |
5476 | } | |
245af2c7 SS |
5477 | } |
5478 | ||
1a848870 | 5479 | if (sd && sd_degenerate(sd)) { |
245af2c7 | 5480 | sd = sd->parent; |
1a848870 SS |
5481 | if (sd) |
5482 | sd->child = NULL; | |
5483 | } | |
1da177e4 LT |
5484 | |
5485 | sched_domain_debug(sd, cpu); | |
5486 | ||
674311d5 | 5487 | rcu_assign_pointer(rq->sd, sd); |
1da177e4 LT |
5488 | } |
5489 | ||
5490 | /* cpus with isolated domains */ | |
67af63a6 | 5491 | static cpumask_t cpu_isolated_map = CPU_MASK_NONE; |
1da177e4 LT |
5492 | |
5493 | /* Setup the mask of cpus configured for isolated domains */ | |
5494 | static int __init isolated_cpu_setup(char *str) | |
5495 | { | |
5496 | int ints[NR_CPUS], i; | |
5497 | ||
5498 | str = get_options(str, ARRAY_SIZE(ints), ints); | |
5499 | cpus_clear(cpu_isolated_map); | |
5500 | for (i = 1; i <= ints[0]; i++) | |
5501 | if (ints[i] < NR_CPUS) | |
5502 | cpu_set(ints[i], cpu_isolated_map); | |
5503 | return 1; | |
5504 | } | |
5505 | ||
5506 | __setup ("isolcpus=", isolated_cpu_setup); | |
5507 | ||
5508 | /* | |
6711cab4 SS |
5509 | * init_sched_build_groups takes the cpumask we wish to span, and a pointer |
5510 | * to a function which identifies what group(along with sched group) a CPU | |
5511 | * belongs to. The return value of group_fn must be a >= 0 and < NR_CPUS | |
5512 | * (due to the fact that we keep track of groups covered with a cpumask_t). | |
1da177e4 LT |
5513 | * |
5514 | * init_sched_build_groups will build a circular linked list of the groups | |
5515 | * covered by the given span, and will set each group's ->cpumask correctly, | |
5516 | * and ->cpu_power to 0. | |
5517 | */ | |
a616058b | 5518 | static void |
6711cab4 SS |
5519 | init_sched_build_groups(cpumask_t span, const cpumask_t *cpu_map, |
5520 | int (*group_fn)(int cpu, const cpumask_t *cpu_map, | |
5521 | struct sched_group **sg)) | |
1da177e4 LT |
5522 | { |
5523 | struct sched_group *first = NULL, *last = NULL; | |
5524 | cpumask_t covered = CPU_MASK_NONE; | |
5525 | int i; | |
5526 | ||
5527 | for_each_cpu_mask(i, span) { | |
6711cab4 SS |
5528 | struct sched_group *sg; |
5529 | int group = group_fn(i, cpu_map, &sg); | |
1da177e4 LT |
5530 | int j; |
5531 | ||
5532 | if (cpu_isset(i, covered)) | |
5533 | continue; | |
5534 | ||
5535 | sg->cpumask = CPU_MASK_NONE; | |
5517d86b | 5536 | sg->__cpu_power = 0; |
1da177e4 LT |
5537 | |
5538 | for_each_cpu_mask(j, span) { | |
6711cab4 | 5539 | if (group_fn(j, cpu_map, NULL) != group) |
1da177e4 LT |
5540 | continue; |
5541 | ||
5542 | cpu_set(j, covered); | |
5543 | cpu_set(j, sg->cpumask); | |
5544 | } | |
5545 | if (!first) | |
5546 | first = sg; | |
5547 | if (last) | |
5548 | last->next = sg; | |
5549 | last = sg; | |
5550 | } | |
5551 | last->next = first; | |
5552 | } | |
5553 | ||
9c1cfda2 | 5554 | #define SD_NODES_PER_DOMAIN 16 |
1da177e4 | 5555 | |
9c1cfda2 | 5556 | #ifdef CONFIG_NUMA |
198e2f18 | 5557 | |
9c1cfda2 JH |
5558 | /** |
5559 | * find_next_best_node - find the next node to include in a sched_domain | |
5560 | * @node: node whose sched_domain we're building | |
5561 | * @used_nodes: nodes already in the sched_domain | |
5562 | * | |
5563 | * Find the next node to include in a given scheduling domain. Simply | |
5564 | * finds the closest node not already in the @used_nodes map. | |
5565 | * | |
5566 | * Should use nodemask_t. | |
5567 | */ | |
5568 | static int find_next_best_node(int node, unsigned long *used_nodes) | |
5569 | { | |
5570 | int i, n, val, min_val, best_node = 0; | |
5571 | ||
5572 | min_val = INT_MAX; | |
5573 | ||
5574 | for (i = 0; i < MAX_NUMNODES; i++) { | |
5575 | /* Start at @node */ | |
5576 | n = (node + i) % MAX_NUMNODES; | |
5577 | ||
5578 | if (!nr_cpus_node(n)) | |
5579 | continue; | |
5580 | ||
5581 | /* Skip already used nodes */ | |
5582 | if (test_bit(n, used_nodes)) | |
5583 | continue; | |
5584 | ||
5585 | /* Simple min distance search */ | |
5586 | val = node_distance(node, n); | |
5587 | ||
5588 | if (val < min_val) { | |
5589 | min_val = val; | |
5590 | best_node = n; | |
5591 | } | |
5592 | } | |
5593 | ||
5594 | set_bit(best_node, used_nodes); | |
5595 | return best_node; | |
5596 | } | |
5597 | ||
5598 | /** | |
5599 | * sched_domain_node_span - get a cpumask for a node's sched_domain | |
5600 | * @node: node whose cpumask we're constructing | |
5601 | * @size: number of nodes to include in this span | |
5602 | * | |
5603 | * Given a node, construct a good cpumask for its sched_domain to span. It | |
5604 | * should be one that prevents unnecessary balancing, but also spreads tasks | |
5605 | * out optimally. | |
5606 | */ | |
5607 | static cpumask_t sched_domain_node_span(int node) | |
5608 | { | |
9c1cfda2 | 5609 | DECLARE_BITMAP(used_nodes, MAX_NUMNODES); |
48f24c4d IM |
5610 | cpumask_t span, nodemask; |
5611 | int i; | |
9c1cfda2 JH |
5612 | |
5613 | cpus_clear(span); | |
5614 | bitmap_zero(used_nodes, MAX_NUMNODES); | |
5615 | ||
5616 | nodemask = node_to_cpumask(node); | |
5617 | cpus_or(span, span, nodemask); | |
5618 | set_bit(node, used_nodes); | |
5619 | ||
5620 | for (i = 1; i < SD_NODES_PER_DOMAIN; i++) { | |
5621 | int next_node = find_next_best_node(node, used_nodes); | |
48f24c4d | 5622 | |
9c1cfda2 JH |
5623 | nodemask = node_to_cpumask(next_node); |
5624 | cpus_or(span, span, nodemask); | |
5625 | } | |
5626 | ||
5627 | return span; | |
5628 | } | |
5629 | #endif | |
5630 | ||
5c45bf27 | 5631 | int sched_smt_power_savings = 0, sched_mc_power_savings = 0; |
48f24c4d | 5632 | |
9c1cfda2 | 5633 | /* |
48f24c4d | 5634 | * SMT sched-domains: |
9c1cfda2 | 5635 | */ |
1da177e4 LT |
5636 | #ifdef CONFIG_SCHED_SMT |
5637 | static DEFINE_PER_CPU(struct sched_domain, cpu_domains); | |
6711cab4 | 5638 | static DEFINE_PER_CPU(struct sched_group, sched_group_cpus); |
48f24c4d | 5639 | |
6711cab4 SS |
5640 | static int cpu_to_cpu_group(int cpu, const cpumask_t *cpu_map, |
5641 | struct sched_group **sg) | |
1da177e4 | 5642 | { |
6711cab4 SS |
5643 | if (sg) |
5644 | *sg = &per_cpu(sched_group_cpus, cpu); | |
1da177e4 LT |
5645 | return cpu; |
5646 | } | |
5647 | #endif | |
5648 | ||
48f24c4d IM |
5649 | /* |
5650 | * multi-core sched-domains: | |
5651 | */ | |
1e9f28fa SS |
5652 | #ifdef CONFIG_SCHED_MC |
5653 | static DEFINE_PER_CPU(struct sched_domain, core_domains); | |
6711cab4 | 5654 | static DEFINE_PER_CPU(struct sched_group, sched_group_core); |
1e9f28fa SS |
5655 | #endif |
5656 | ||
5657 | #if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT) | |
6711cab4 SS |
5658 | static int cpu_to_core_group(int cpu, const cpumask_t *cpu_map, |
5659 | struct sched_group **sg) | |
1e9f28fa | 5660 | { |
6711cab4 | 5661 | int group; |
a616058b SS |
5662 | cpumask_t mask = cpu_sibling_map[cpu]; |
5663 | cpus_and(mask, mask, *cpu_map); | |
6711cab4 SS |
5664 | group = first_cpu(mask); |
5665 | if (sg) | |
5666 | *sg = &per_cpu(sched_group_core, group); | |
5667 | return group; | |
1e9f28fa SS |
5668 | } |
5669 | #elif defined(CONFIG_SCHED_MC) | |
6711cab4 SS |
5670 | static int cpu_to_core_group(int cpu, const cpumask_t *cpu_map, |
5671 | struct sched_group **sg) | |
1e9f28fa | 5672 | { |
6711cab4 SS |
5673 | if (sg) |
5674 | *sg = &per_cpu(sched_group_core, cpu); | |
1e9f28fa SS |
5675 | return cpu; |
5676 | } | |
5677 | #endif | |
5678 | ||
1da177e4 | 5679 | static DEFINE_PER_CPU(struct sched_domain, phys_domains); |
6711cab4 | 5680 | static DEFINE_PER_CPU(struct sched_group, sched_group_phys); |
48f24c4d | 5681 | |
6711cab4 SS |
5682 | static int cpu_to_phys_group(int cpu, const cpumask_t *cpu_map, |
5683 | struct sched_group **sg) | |
1da177e4 | 5684 | { |
6711cab4 | 5685 | int group; |
48f24c4d | 5686 | #ifdef CONFIG_SCHED_MC |
1e9f28fa | 5687 | cpumask_t mask = cpu_coregroup_map(cpu); |
a616058b | 5688 | cpus_and(mask, mask, *cpu_map); |
6711cab4 | 5689 | group = first_cpu(mask); |
1e9f28fa | 5690 | #elif defined(CONFIG_SCHED_SMT) |
a616058b SS |
5691 | cpumask_t mask = cpu_sibling_map[cpu]; |
5692 | cpus_and(mask, mask, *cpu_map); | |
6711cab4 | 5693 | group = first_cpu(mask); |
1da177e4 | 5694 | #else |
6711cab4 | 5695 | group = cpu; |
1da177e4 | 5696 | #endif |
6711cab4 SS |
5697 | if (sg) |
5698 | *sg = &per_cpu(sched_group_phys, group); | |
5699 | return group; | |
1da177e4 LT |
5700 | } |
5701 | ||
5702 | #ifdef CONFIG_NUMA | |
1da177e4 | 5703 | /* |
9c1cfda2 JH |
5704 | * The init_sched_build_groups can't handle what we want to do with node |
5705 | * groups, so roll our own. Now each node has its own list of groups which | |
5706 | * gets dynamically allocated. | |
1da177e4 | 5707 | */ |
9c1cfda2 | 5708 | static DEFINE_PER_CPU(struct sched_domain, node_domains); |
d1b55138 | 5709 | static struct sched_group **sched_group_nodes_bycpu[NR_CPUS]; |
1da177e4 | 5710 | |
9c1cfda2 | 5711 | static DEFINE_PER_CPU(struct sched_domain, allnodes_domains); |
6711cab4 | 5712 | static DEFINE_PER_CPU(struct sched_group, sched_group_allnodes); |
9c1cfda2 | 5713 | |
6711cab4 SS |
5714 | static int cpu_to_allnodes_group(int cpu, const cpumask_t *cpu_map, |
5715 | struct sched_group **sg) | |
9c1cfda2 | 5716 | { |
6711cab4 SS |
5717 | cpumask_t nodemask = node_to_cpumask(cpu_to_node(cpu)); |
5718 | int group; | |
5719 | ||
5720 | cpus_and(nodemask, nodemask, *cpu_map); | |
5721 | group = first_cpu(nodemask); | |
5722 | ||
5723 | if (sg) | |
5724 | *sg = &per_cpu(sched_group_allnodes, group); | |
5725 | return group; | |
1da177e4 | 5726 | } |
6711cab4 | 5727 | |
08069033 SS |
5728 | static void init_numa_sched_groups_power(struct sched_group *group_head) |
5729 | { | |
5730 | struct sched_group *sg = group_head; | |
5731 | int j; | |
5732 | ||
5733 | if (!sg) | |
5734 | return; | |
5735 | next_sg: | |
5736 | for_each_cpu_mask(j, sg->cpumask) { | |
5737 | struct sched_domain *sd; | |
5738 | ||
5739 | sd = &per_cpu(phys_domains, j); | |
5740 | if (j != first_cpu(sd->groups->cpumask)) { | |
5741 | /* | |
5742 | * Only add "power" once for each | |
5743 | * physical package. | |
5744 | */ | |
5745 | continue; | |
5746 | } | |
5747 | ||
5517d86b | 5748 | sg_inc_cpu_power(sg, sd->groups->__cpu_power); |
08069033 SS |
5749 | } |
5750 | sg = sg->next; | |
5751 | if (sg != group_head) | |
5752 | goto next_sg; | |
5753 | } | |
1da177e4 LT |
5754 | #endif |
5755 | ||
a616058b | 5756 | #ifdef CONFIG_NUMA |
51888ca2 SV |
5757 | /* Free memory allocated for various sched_group structures */ |
5758 | static void free_sched_groups(const cpumask_t *cpu_map) | |
5759 | { | |
a616058b | 5760 | int cpu, i; |
51888ca2 SV |
5761 | |
5762 | for_each_cpu_mask(cpu, *cpu_map) { | |
51888ca2 SV |
5763 | struct sched_group **sched_group_nodes |
5764 | = sched_group_nodes_bycpu[cpu]; | |
5765 | ||
51888ca2 SV |
5766 | if (!sched_group_nodes) |
5767 | continue; | |
5768 | ||
5769 | for (i = 0; i < MAX_NUMNODES; i++) { | |
5770 | cpumask_t nodemask = node_to_cpumask(i); | |
5771 | struct sched_group *oldsg, *sg = sched_group_nodes[i]; | |
5772 | ||
5773 | cpus_and(nodemask, nodemask, *cpu_map); | |
5774 | if (cpus_empty(nodemask)) | |
5775 | continue; | |
5776 | ||
5777 | if (sg == NULL) | |
5778 | continue; | |
5779 | sg = sg->next; | |
5780 | next_sg: | |
5781 | oldsg = sg; | |
5782 | sg = sg->next; | |
5783 | kfree(oldsg); | |
5784 | if (oldsg != sched_group_nodes[i]) | |
5785 | goto next_sg; | |
5786 | } | |
5787 | kfree(sched_group_nodes); | |
5788 | sched_group_nodes_bycpu[cpu] = NULL; | |
5789 | } | |
51888ca2 | 5790 | } |
a616058b SS |
5791 | #else |
5792 | static void free_sched_groups(const cpumask_t *cpu_map) | |
5793 | { | |
5794 | } | |
5795 | #endif | |
51888ca2 | 5796 | |
89c4710e SS |
5797 | /* |
5798 | * Initialize sched groups cpu_power. | |
5799 | * | |
5800 | * cpu_power indicates the capacity of sched group, which is used while | |
5801 | * distributing the load between different sched groups in a sched domain. | |
5802 | * Typically cpu_power for all the groups in a sched domain will be same unless | |
5803 | * there are asymmetries in the topology. If there are asymmetries, group | |
5804 | * having more cpu_power will pickup more load compared to the group having | |
5805 | * less cpu_power. | |
5806 | * | |
5807 | * cpu_power will be a multiple of SCHED_LOAD_SCALE. This multiple represents | |
5808 | * the maximum number of tasks a group can handle in the presence of other idle | |
5809 | * or lightly loaded groups in the same sched domain. | |
5810 | */ | |
5811 | static void init_sched_groups_power(int cpu, struct sched_domain *sd) | |
5812 | { | |
5813 | struct sched_domain *child; | |
5814 | struct sched_group *group; | |
5815 | ||
5816 | WARN_ON(!sd || !sd->groups); | |
5817 | ||
5818 | if (cpu != first_cpu(sd->groups->cpumask)) | |
5819 | return; | |
5820 | ||
5821 | child = sd->child; | |
5822 | ||
5517d86b ED |
5823 | sd->groups->__cpu_power = 0; |
5824 | ||
89c4710e SS |
5825 | /* |
5826 | * For perf policy, if the groups in child domain share resources | |
5827 | * (for example cores sharing some portions of the cache hierarchy | |
5828 | * or SMT), then set this domain groups cpu_power such that each group | |
5829 | * can handle only one task, when there are other idle groups in the | |
5830 | * same sched domain. | |
5831 | */ | |
5832 | if (!child || (!(sd->flags & SD_POWERSAVINGS_BALANCE) && | |
5833 | (child->flags & | |
5834 | (SD_SHARE_CPUPOWER | SD_SHARE_PKG_RESOURCES)))) { | |
5517d86b | 5835 | sg_inc_cpu_power(sd->groups, SCHED_LOAD_SCALE); |
89c4710e SS |
5836 | return; |
5837 | } | |
5838 | ||
89c4710e SS |
5839 | /* |
5840 | * add cpu_power of each child group to this groups cpu_power | |
5841 | */ | |
5842 | group = child->groups; | |
5843 | do { | |
5517d86b | 5844 | sg_inc_cpu_power(sd->groups, group->__cpu_power); |
89c4710e SS |
5845 | group = group->next; |
5846 | } while (group != child->groups); | |
5847 | } | |
5848 | ||
1da177e4 | 5849 | /* |
1a20ff27 DG |
5850 | * Build sched domains for a given set of cpus and attach the sched domains |
5851 | * to the individual cpus | |
1da177e4 | 5852 | */ |
51888ca2 | 5853 | static int build_sched_domains(const cpumask_t *cpu_map) |
1da177e4 LT |
5854 | { |
5855 | int i; | |
d1b55138 JH |
5856 | #ifdef CONFIG_NUMA |
5857 | struct sched_group **sched_group_nodes = NULL; | |
6711cab4 | 5858 | int sd_allnodes = 0; |
d1b55138 JH |
5859 | |
5860 | /* | |
5861 | * Allocate the per-node list of sched groups | |
5862 | */ | |
dd41f596 | 5863 | sched_group_nodes = kzalloc(sizeof(struct sched_group *)*MAX_NUMNODES, |
d3a5aa98 | 5864 | GFP_KERNEL); |
d1b55138 JH |
5865 | if (!sched_group_nodes) { |
5866 | printk(KERN_WARNING "Can not alloc sched group node list\n"); | |
51888ca2 | 5867 | return -ENOMEM; |
d1b55138 JH |
5868 | } |
5869 | sched_group_nodes_bycpu[first_cpu(*cpu_map)] = sched_group_nodes; | |
5870 | #endif | |
1da177e4 LT |
5871 | |
5872 | /* | |
1a20ff27 | 5873 | * Set up domains for cpus specified by the cpu_map. |
1da177e4 | 5874 | */ |
1a20ff27 | 5875 | for_each_cpu_mask(i, *cpu_map) { |
1da177e4 LT |
5876 | struct sched_domain *sd = NULL, *p; |
5877 | cpumask_t nodemask = node_to_cpumask(cpu_to_node(i)); | |
5878 | ||
1a20ff27 | 5879 | cpus_and(nodemask, nodemask, *cpu_map); |
1da177e4 LT |
5880 | |
5881 | #ifdef CONFIG_NUMA | |
dd41f596 IM |
5882 | if (cpus_weight(*cpu_map) > |
5883 | SD_NODES_PER_DOMAIN*cpus_weight(nodemask)) { | |
9c1cfda2 JH |
5884 | sd = &per_cpu(allnodes_domains, i); |
5885 | *sd = SD_ALLNODES_INIT; | |
5886 | sd->span = *cpu_map; | |
6711cab4 | 5887 | cpu_to_allnodes_group(i, cpu_map, &sd->groups); |
9c1cfda2 | 5888 | p = sd; |
6711cab4 | 5889 | sd_allnodes = 1; |
9c1cfda2 JH |
5890 | } else |
5891 | p = NULL; | |
5892 | ||
1da177e4 | 5893 | sd = &per_cpu(node_domains, i); |
1da177e4 | 5894 | *sd = SD_NODE_INIT; |
9c1cfda2 JH |
5895 | sd->span = sched_domain_node_span(cpu_to_node(i)); |
5896 | sd->parent = p; | |
1a848870 SS |
5897 | if (p) |
5898 | p->child = sd; | |
9c1cfda2 | 5899 | cpus_and(sd->span, sd->span, *cpu_map); |
1da177e4 LT |
5900 | #endif |
5901 | ||
5902 | p = sd; | |
5903 | sd = &per_cpu(phys_domains, i); | |
1da177e4 LT |
5904 | *sd = SD_CPU_INIT; |
5905 | sd->span = nodemask; | |
5906 | sd->parent = p; | |
1a848870 SS |
5907 | if (p) |
5908 | p->child = sd; | |
6711cab4 | 5909 | cpu_to_phys_group(i, cpu_map, &sd->groups); |
1da177e4 | 5910 | |
1e9f28fa SS |
5911 | #ifdef CONFIG_SCHED_MC |
5912 | p = sd; | |
5913 | sd = &per_cpu(core_domains, i); | |
1e9f28fa SS |
5914 | *sd = SD_MC_INIT; |
5915 | sd->span = cpu_coregroup_map(i); | |
5916 | cpus_and(sd->span, sd->span, *cpu_map); | |
5917 | sd->parent = p; | |
1a848870 | 5918 | p->child = sd; |
6711cab4 | 5919 | cpu_to_core_group(i, cpu_map, &sd->groups); |
1e9f28fa SS |
5920 | #endif |
5921 | ||
1da177e4 LT |
5922 | #ifdef CONFIG_SCHED_SMT |
5923 | p = sd; | |
5924 | sd = &per_cpu(cpu_domains, i); | |
1da177e4 LT |
5925 | *sd = SD_SIBLING_INIT; |
5926 | sd->span = cpu_sibling_map[i]; | |
1a20ff27 | 5927 | cpus_and(sd->span, sd->span, *cpu_map); |
1da177e4 | 5928 | sd->parent = p; |
1a848870 | 5929 | p->child = sd; |
6711cab4 | 5930 | cpu_to_cpu_group(i, cpu_map, &sd->groups); |
1da177e4 LT |
5931 | #endif |
5932 | } | |
5933 | ||
5934 | #ifdef CONFIG_SCHED_SMT | |
5935 | /* Set up CPU (sibling) groups */ | |
9c1cfda2 | 5936 | for_each_cpu_mask(i, *cpu_map) { |
1da177e4 | 5937 | cpumask_t this_sibling_map = cpu_sibling_map[i]; |
1a20ff27 | 5938 | cpus_and(this_sibling_map, this_sibling_map, *cpu_map); |
1da177e4 LT |
5939 | if (i != first_cpu(this_sibling_map)) |
5940 | continue; | |
5941 | ||
dd41f596 IM |
5942 | init_sched_build_groups(this_sibling_map, cpu_map, |
5943 | &cpu_to_cpu_group); | |
1da177e4 LT |
5944 | } |
5945 | #endif | |
5946 | ||
1e9f28fa SS |
5947 | #ifdef CONFIG_SCHED_MC |
5948 | /* Set up multi-core groups */ | |
5949 | for_each_cpu_mask(i, *cpu_map) { | |
5950 | cpumask_t this_core_map = cpu_coregroup_map(i); | |
5951 | cpus_and(this_core_map, this_core_map, *cpu_map); | |
5952 | if (i != first_cpu(this_core_map)) | |
5953 | continue; | |
dd41f596 IM |
5954 | init_sched_build_groups(this_core_map, cpu_map, |
5955 | &cpu_to_core_group); | |
1e9f28fa SS |
5956 | } |
5957 | #endif | |
5958 | ||
1da177e4 LT |
5959 | /* Set up physical groups */ |
5960 | for (i = 0; i < MAX_NUMNODES; i++) { | |
5961 | cpumask_t nodemask = node_to_cpumask(i); | |
5962 | ||
1a20ff27 | 5963 | cpus_and(nodemask, nodemask, *cpu_map); |
1da177e4 LT |
5964 | if (cpus_empty(nodemask)) |
5965 | continue; | |
5966 | ||
6711cab4 | 5967 | init_sched_build_groups(nodemask, cpu_map, &cpu_to_phys_group); |
1da177e4 LT |
5968 | } |
5969 | ||
5970 | #ifdef CONFIG_NUMA | |
5971 | /* Set up node groups */ | |
6711cab4 | 5972 | if (sd_allnodes) |
dd41f596 IM |
5973 | init_sched_build_groups(*cpu_map, cpu_map, |
5974 | &cpu_to_allnodes_group); | |
9c1cfda2 JH |
5975 | |
5976 | for (i = 0; i < MAX_NUMNODES; i++) { | |
5977 | /* Set up node groups */ | |
5978 | struct sched_group *sg, *prev; | |
5979 | cpumask_t nodemask = node_to_cpumask(i); | |
5980 | cpumask_t domainspan; | |
5981 | cpumask_t covered = CPU_MASK_NONE; | |
5982 | int j; | |
5983 | ||
5984 | cpus_and(nodemask, nodemask, *cpu_map); | |
d1b55138 JH |
5985 | if (cpus_empty(nodemask)) { |
5986 | sched_group_nodes[i] = NULL; | |
9c1cfda2 | 5987 | continue; |
d1b55138 | 5988 | } |
9c1cfda2 JH |
5989 | |
5990 | domainspan = sched_domain_node_span(i); | |
5991 | cpus_and(domainspan, domainspan, *cpu_map); | |
5992 | ||
15f0b676 | 5993 | sg = kmalloc_node(sizeof(struct sched_group), GFP_KERNEL, i); |
51888ca2 SV |
5994 | if (!sg) { |
5995 | printk(KERN_WARNING "Can not alloc domain group for " | |
5996 | "node %d\n", i); | |
5997 | goto error; | |
5998 | } | |
9c1cfda2 JH |
5999 | sched_group_nodes[i] = sg; |
6000 | for_each_cpu_mask(j, nodemask) { | |
6001 | struct sched_domain *sd; | |
6002 | sd = &per_cpu(node_domains, j); | |
6003 | sd->groups = sg; | |
9c1cfda2 | 6004 | } |
5517d86b | 6005 | sg->__cpu_power = 0; |
9c1cfda2 | 6006 | sg->cpumask = nodemask; |
51888ca2 | 6007 | sg->next = sg; |
9c1cfda2 JH |
6008 | cpus_or(covered, covered, nodemask); |
6009 | prev = sg; | |
6010 | ||
6011 | for (j = 0; j < MAX_NUMNODES; j++) { | |
6012 | cpumask_t tmp, notcovered; | |
6013 | int n = (i + j) % MAX_NUMNODES; | |
6014 | ||
6015 | cpus_complement(notcovered, covered); | |
6016 | cpus_and(tmp, notcovered, *cpu_map); | |
6017 | cpus_and(tmp, tmp, domainspan); | |
6018 | if (cpus_empty(tmp)) | |
6019 | break; | |
6020 | ||
6021 | nodemask = node_to_cpumask(n); | |
6022 | cpus_and(tmp, tmp, nodemask); | |
6023 | if (cpus_empty(tmp)) | |
6024 | continue; | |
6025 | ||
15f0b676 SV |
6026 | sg = kmalloc_node(sizeof(struct sched_group), |
6027 | GFP_KERNEL, i); | |
9c1cfda2 JH |
6028 | if (!sg) { |
6029 | printk(KERN_WARNING | |
6030 | "Can not alloc domain group for node %d\n", j); | |
51888ca2 | 6031 | goto error; |
9c1cfda2 | 6032 | } |
5517d86b | 6033 | sg->__cpu_power = 0; |
9c1cfda2 | 6034 | sg->cpumask = tmp; |
51888ca2 | 6035 | sg->next = prev->next; |
9c1cfda2 JH |
6036 | cpus_or(covered, covered, tmp); |
6037 | prev->next = sg; | |
6038 | prev = sg; | |
6039 | } | |
9c1cfda2 | 6040 | } |
1da177e4 LT |
6041 | #endif |
6042 | ||
6043 | /* Calculate CPU power for physical packages and nodes */ | |
5c45bf27 | 6044 | #ifdef CONFIG_SCHED_SMT |
1a20ff27 | 6045 | for_each_cpu_mask(i, *cpu_map) { |
dd41f596 IM |
6046 | struct sched_domain *sd = &per_cpu(cpu_domains, i); |
6047 | ||
89c4710e | 6048 | init_sched_groups_power(i, sd); |
5c45bf27 | 6049 | } |
1da177e4 | 6050 | #endif |
1e9f28fa | 6051 | #ifdef CONFIG_SCHED_MC |
5c45bf27 | 6052 | for_each_cpu_mask(i, *cpu_map) { |
dd41f596 IM |
6053 | struct sched_domain *sd = &per_cpu(core_domains, i); |
6054 | ||
89c4710e | 6055 | init_sched_groups_power(i, sd); |
5c45bf27 SS |
6056 | } |
6057 | #endif | |
1e9f28fa | 6058 | |
5c45bf27 | 6059 | for_each_cpu_mask(i, *cpu_map) { |
dd41f596 IM |
6060 | struct sched_domain *sd = &per_cpu(phys_domains, i); |
6061 | ||
89c4710e | 6062 | init_sched_groups_power(i, sd); |
1da177e4 LT |
6063 | } |
6064 | ||
9c1cfda2 | 6065 | #ifdef CONFIG_NUMA |
08069033 SS |
6066 | for (i = 0; i < MAX_NUMNODES; i++) |
6067 | init_numa_sched_groups_power(sched_group_nodes[i]); | |
9c1cfda2 | 6068 | |
6711cab4 SS |
6069 | if (sd_allnodes) { |
6070 | struct sched_group *sg; | |
f712c0c7 | 6071 | |
6711cab4 | 6072 | cpu_to_allnodes_group(first_cpu(*cpu_map), cpu_map, &sg); |
f712c0c7 SS |
6073 | init_numa_sched_groups_power(sg); |
6074 | } | |
9c1cfda2 JH |
6075 | #endif |
6076 | ||
1da177e4 | 6077 | /* Attach the domains */ |
1a20ff27 | 6078 | for_each_cpu_mask(i, *cpu_map) { |
1da177e4 LT |
6079 | struct sched_domain *sd; |
6080 | #ifdef CONFIG_SCHED_SMT | |
6081 | sd = &per_cpu(cpu_domains, i); | |
1e9f28fa SS |
6082 | #elif defined(CONFIG_SCHED_MC) |
6083 | sd = &per_cpu(core_domains, i); | |
1da177e4 LT |
6084 | #else |
6085 | sd = &per_cpu(phys_domains, i); | |
6086 | #endif | |
6087 | cpu_attach_domain(sd, i); | |
6088 | } | |
51888ca2 SV |
6089 | |
6090 | return 0; | |
6091 | ||
a616058b | 6092 | #ifdef CONFIG_NUMA |
51888ca2 SV |
6093 | error: |
6094 | free_sched_groups(cpu_map); | |
6095 | return -ENOMEM; | |
a616058b | 6096 | #endif |
1da177e4 | 6097 | } |
1a20ff27 DG |
6098 | /* |
6099 | * Set up scheduler domains and groups. Callers must hold the hotplug lock. | |
6100 | */ | |
51888ca2 | 6101 | static int arch_init_sched_domains(const cpumask_t *cpu_map) |
1a20ff27 DG |
6102 | { |
6103 | cpumask_t cpu_default_map; | |
51888ca2 | 6104 | int err; |
1da177e4 | 6105 | |
1a20ff27 DG |
6106 | /* |
6107 | * Setup mask for cpus without special case scheduling requirements. | |
6108 | * For now this just excludes isolated cpus, but could be used to | |
6109 | * exclude other special cases in the future. | |
6110 | */ | |
6111 | cpus_andnot(cpu_default_map, *cpu_map, cpu_isolated_map); | |
6112 | ||
51888ca2 SV |
6113 | err = build_sched_domains(&cpu_default_map); |
6114 | ||
6115 | return err; | |
1a20ff27 DG |
6116 | } |
6117 | ||
6118 | static void arch_destroy_sched_domains(const cpumask_t *cpu_map) | |
1da177e4 | 6119 | { |
51888ca2 | 6120 | free_sched_groups(cpu_map); |
9c1cfda2 | 6121 | } |
1da177e4 | 6122 | |
1a20ff27 DG |
6123 | /* |
6124 | * Detach sched domains from a group of cpus specified in cpu_map | |
6125 | * These cpus will now be attached to the NULL domain | |
6126 | */ | |
858119e1 | 6127 | static void detach_destroy_domains(const cpumask_t *cpu_map) |
1a20ff27 DG |
6128 | { |
6129 | int i; | |
6130 | ||
6131 | for_each_cpu_mask(i, *cpu_map) | |
6132 | cpu_attach_domain(NULL, i); | |
6133 | synchronize_sched(); | |
6134 | arch_destroy_sched_domains(cpu_map); | |
6135 | } | |
6136 | ||
6137 | /* | |
6138 | * Partition sched domains as specified by the cpumasks below. | |
6139 | * This attaches all cpus from the cpumasks to the NULL domain, | |
6140 | * waits for a RCU quiescent period, recalculates sched | |
6141 | * domain information and then attaches them back to the | |
6142 | * correct sched domains | |
6143 | * Call with hotplug lock held | |
6144 | */ | |
51888ca2 | 6145 | int partition_sched_domains(cpumask_t *partition1, cpumask_t *partition2) |
1a20ff27 DG |
6146 | { |
6147 | cpumask_t change_map; | |
51888ca2 | 6148 | int err = 0; |
1a20ff27 DG |
6149 | |
6150 | cpus_and(*partition1, *partition1, cpu_online_map); | |
6151 | cpus_and(*partition2, *partition2, cpu_online_map); | |
6152 | cpus_or(change_map, *partition1, *partition2); | |
6153 | ||
6154 | /* Detach sched domains from all of the affected cpus */ | |
6155 | detach_destroy_domains(&change_map); | |
6156 | if (!cpus_empty(*partition1)) | |
51888ca2 SV |
6157 | err = build_sched_domains(partition1); |
6158 | if (!err && !cpus_empty(*partition2)) | |
6159 | err = build_sched_domains(partition2); | |
6160 | ||
6161 | return err; | |
1a20ff27 DG |
6162 | } |
6163 | ||
5c45bf27 SS |
6164 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) |
6165 | int arch_reinit_sched_domains(void) | |
6166 | { | |
6167 | int err; | |
6168 | ||
5be9361c | 6169 | mutex_lock(&sched_hotcpu_mutex); |
5c45bf27 SS |
6170 | detach_destroy_domains(&cpu_online_map); |
6171 | err = arch_init_sched_domains(&cpu_online_map); | |
5be9361c | 6172 | mutex_unlock(&sched_hotcpu_mutex); |
5c45bf27 SS |
6173 | |
6174 | return err; | |
6175 | } | |
6176 | ||
6177 | static ssize_t sched_power_savings_store(const char *buf, size_t count, int smt) | |
6178 | { | |
6179 | int ret; | |
6180 | ||
6181 | if (buf[0] != '0' && buf[0] != '1') | |
6182 | return -EINVAL; | |
6183 | ||
6184 | if (smt) | |
6185 | sched_smt_power_savings = (buf[0] == '1'); | |
6186 | else | |
6187 | sched_mc_power_savings = (buf[0] == '1'); | |
6188 | ||
6189 | ret = arch_reinit_sched_domains(); | |
6190 | ||
6191 | return ret ? ret : count; | |
6192 | } | |
6193 | ||
6194 | int sched_create_sysfs_power_savings_entries(struct sysdev_class *cls) | |
6195 | { | |
6196 | int err = 0; | |
48f24c4d | 6197 | |
5c45bf27 SS |
6198 | #ifdef CONFIG_SCHED_SMT |
6199 | if (smt_capable()) | |
6200 | err = sysfs_create_file(&cls->kset.kobj, | |
6201 | &attr_sched_smt_power_savings.attr); | |
6202 | #endif | |
6203 | #ifdef CONFIG_SCHED_MC | |
6204 | if (!err && mc_capable()) | |
6205 | err = sysfs_create_file(&cls->kset.kobj, | |
6206 | &attr_sched_mc_power_savings.attr); | |
6207 | #endif | |
6208 | return err; | |
6209 | } | |
6210 | #endif | |
6211 | ||
6212 | #ifdef CONFIG_SCHED_MC | |
6213 | static ssize_t sched_mc_power_savings_show(struct sys_device *dev, char *page) | |
6214 | { | |
6215 | return sprintf(page, "%u\n", sched_mc_power_savings); | |
6216 | } | |
48f24c4d IM |
6217 | static ssize_t sched_mc_power_savings_store(struct sys_device *dev, |
6218 | const char *buf, size_t count) | |
5c45bf27 SS |
6219 | { |
6220 | return sched_power_savings_store(buf, count, 0); | |
6221 | } | |
6222 | SYSDEV_ATTR(sched_mc_power_savings, 0644, sched_mc_power_savings_show, | |
6223 | sched_mc_power_savings_store); | |
6224 | #endif | |
6225 | ||
6226 | #ifdef CONFIG_SCHED_SMT | |
6227 | static ssize_t sched_smt_power_savings_show(struct sys_device *dev, char *page) | |
6228 | { | |
6229 | return sprintf(page, "%u\n", sched_smt_power_savings); | |
6230 | } | |
48f24c4d IM |
6231 | static ssize_t sched_smt_power_savings_store(struct sys_device *dev, |
6232 | const char *buf, size_t count) | |
5c45bf27 SS |
6233 | { |
6234 | return sched_power_savings_store(buf, count, 1); | |
6235 | } | |
6236 | SYSDEV_ATTR(sched_smt_power_savings, 0644, sched_smt_power_savings_show, | |
6237 | sched_smt_power_savings_store); | |
6238 | #endif | |
6239 | ||
1da177e4 LT |
6240 | /* |
6241 | * Force a reinitialization of the sched domains hierarchy. The domains | |
6242 | * and groups cannot be updated in place without racing with the balancing | |
41c7ce9a | 6243 | * code, so we temporarily attach all running cpus to the NULL domain |
1da177e4 LT |
6244 | * which will prevent rebalancing while the sched domains are recalculated. |
6245 | */ | |
6246 | static int update_sched_domains(struct notifier_block *nfb, | |
6247 | unsigned long action, void *hcpu) | |
6248 | { | |
1da177e4 LT |
6249 | switch (action) { |
6250 | case CPU_UP_PREPARE: | |
8bb78442 | 6251 | case CPU_UP_PREPARE_FROZEN: |
1da177e4 | 6252 | case CPU_DOWN_PREPARE: |
8bb78442 | 6253 | case CPU_DOWN_PREPARE_FROZEN: |
1a20ff27 | 6254 | detach_destroy_domains(&cpu_online_map); |
1da177e4 LT |
6255 | return NOTIFY_OK; |
6256 | ||
6257 | case CPU_UP_CANCELED: | |
8bb78442 | 6258 | case CPU_UP_CANCELED_FROZEN: |
1da177e4 | 6259 | case CPU_DOWN_FAILED: |
8bb78442 | 6260 | case CPU_DOWN_FAILED_FROZEN: |
1da177e4 | 6261 | case CPU_ONLINE: |
8bb78442 | 6262 | case CPU_ONLINE_FROZEN: |
1da177e4 | 6263 | case CPU_DEAD: |
8bb78442 | 6264 | case CPU_DEAD_FROZEN: |
1da177e4 LT |
6265 | /* |
6266 | * Fall through and re-initialise the domains. | |
6267 | */ | |
6268 | break; | |
6269 | default: | |
6270 | return NOTIFY_DONE; | |
6271 | } | |
6272 | ||
6273 | /* The hotplug lock is already held by cpu_up/cpu_down */ | |
1a20ff27 | 6274 | arch_init_sched_domains(&cpu_online_map); |
1da177e4 LT |
6275 | |
6276 | return NOTIFY_OK; | |
6277 | } | |
1da177e4 LT |
6278 | |
6279 | void __init sched_init_smp(void) | |
6280 | { | |
5c1e1767 NP |
6281 | cpumask_t non_isolated_cpus; |
6282 | ||
5be9361c | 6283 | mutex_lock(&sched_hotcpu_mutex); |
1a20ff27 | 6284 | arch_init_sched_domains(&cpu_online_map); |
e5e5673f | 6285 | cpus_andnot(non_isolated_cpus, cpu_possible_map, cpu_isolated_map); |
5c1e1767 NP |
6286 | if (cpus_empty(non_isolated_cpus)) |
6287 | cpu_set(smp_processor_id(), non_isolated_cpus); | |
5be9361c | 6288 | mutex_unlock(&sched_hotcpu_mutex); |
1da177e4 LT |
6289 | /* XXX: Theoretical race here - CPU may be hotplugged now */ |
6290 | hotcpu_notifier(update_sched_domains, 0); | |
5c1e1767 NP |
6291 | |
6292 | /* Move init over to a non-isolated CPU */ | |
6293 | if (set_cpus_allowed(current, non_isolated_cpus) < 0) | |
6294 | BUG(); | |
dd41f596 | 6295 | sched_init_granularity(); |
1da177e4 LT |
6296 | } |
6297 | #else | |
6298 | void __init sched_init_smp(void) | |
6299 | { | |
dd41f596 | 6300 | sched_init_granularity(); |
1da177e4 LT |
6301 | } |
6302 | #endif /* CONFIG_SMP */ | |
6303 | ||
6304 | int in_sched_functions(unsigned long addr) | |
6305 | { | |
6306 | /* Linker adds these: start and end of __sched functions */ | |
6307 | extern char __sched_text_start[], __sched_text_end[]; | |
48f24c4d | 6308 | |
1da177e4 LT |
6309 | return in_lock_functions(addr) || |
6310 | (addr >= (unsigned long)__sched_text_start | |
6311 | && addr < (unsigned long)__sched_text_end); | |
6312 | } | |
6313 | ||
dd41f596 IM |
6314 | static inline void init_cfs_rq(struct cfs_rq *cfs_rq, struct rq *rq) |
6315 | { | |
6316 | cfs_rq->tasks_timeline = RB_ROOT; | |
6317 | cfs_rq->fair_clock = 1; | |
6318 | #ifdef CONFIG_FAIR_GROUP_SCHED | |
6319 | cfs_rq->rq = rq; | |
6320 | #endif | |
6321 | } | |
6322 | ||
1da177e4 LT |
6323 | void __init sched_init(void) |
6324 | { | |
dd41f596 | 6325 | u64 now = sched_clock(); |
476f3534 | 6326 | int highest_cpu = 0; |
dd41f596 IM |
6327 | int i, j; |
6328 | ||
6329 | /* | |
6330 | * Link up the scheduling class hierarchy: | |
6331 | */ | |
6332 | rt_sched_class.next = &fair_sched_class; | |
6333 | fair_sched_class.next = &idle_sched_class; | |
6334 | idle_sched_class.next = NULL; | |
1da177e4 | 6335 | |
0a945022 | 6336 | for_each_possible_cpu(i) { |
dd41f596 | 6337 | struct rt_prio_array *array; |
70b97a7f | 6338 | struct rq *rq; |
1da177e4 LT |
6339 | |
6340 | rq = cpu_rq(i); | |
6341 | spin_lock_init(&rq->lock); | |
fcb99371 | 6342 | lockdep_set_class(&rq->lock, &rq->rq_lock_key); |
7897986b | 6343 | rq->nr_running = 0; |
dd41f596 IM |
6344 | rq->clock = 1; |
6345 | init_cfs_rq(&rq->cfs, rq); | |
6346 | #ifdef CONFIG_FAIR_GROUP_SCHED | |
6347 | INIT_LIST_HEAD(&rq->leaf_cfs_rq_list); | |
6348 | list_add(&rq->cfs.leaf_cfs_rq_list, &rq->leaf_cfs_rq_list); | |
6349 | #endif | |
6350 | rq->ls.load_update_last = now; | |
6351 | rq->ls.load_update_start = now; | |
1da177e4 | 6352 | |
dd41f596 IM |
6353 | for (j = 0; j < CPU_LOAD_IDX_MAX; j++) |
6354 | rq->cpu_load[j] = 0; | |
1da177e4 | 6355 | #ifdef CONFIG_SMP |
41c7ce9a | 6356 | rq->sd = NULL; |
1da177e4 | 6357 | rq->active_balance = 0; |
dd41f596 | 6358 | rq->next_balance = jiffies; |
1da177e4 | 6359 | rq->push_cpu = 0; |
0a2966b4 | 6360 | rq->cpu = i; |
1da177e4 LT |
6361 | rq->migration_thread = NULL; |
6362 | INIT_LIST_HEAD(&rq->migration_queue); | |
6363 | #endif | |
6364 | atomic_set(&rq->nr_iowait, 0); | |
6365 | ||
dd41f596 IM |
6366 | array = &rq->rt.active; |
6367 | for (j = 0; j < MAX_RT_PRIO; j++) { | |
6368 | INIT_LIST_HEAD(array->queue + j); | |
6369 | __clear_bit(j, array->bitmap); | |
1da177e4 | 6370 | } |
476f3534 | 6371 | highest_cpu = i; |
dd41f596 IM |
6372 | /* delimiter for bitsearch: */ |
6373 | __set_bit(MAX_RT_PRIO, array->bitmap); | |
1da177e4 LT |
6374 | } |
6375 | ||
2dd73a4f | 6376 | set_load_weight(&init_task); |
b50f60ce | 6377 | |
c9819f45 | 6378 | #ifdef CONFIG_SMP |
476f3534 | 6379 | nr_cpu_ids = highest_cpu + 1; |
c9819f45 CL |
6380 | open_softirq(SCHED_SOFTIRQ, run_rebalance_domains, NULL); |
6381 | #endif | |
6382 | ||
b50f60ce HC |
6383 | #ifdef CONFIG_RT_MUTEXES |
6384 | plist_head_init(&init_task.pi_waiters, &init_task.pi_lock); | |
6385 | #endif | |
6386 | ||
1da177e4 LT |
6387 | /* |
6388 | * The boot idle thread does lazy MMU switching as well: | |
6389 | */ | |
6390 | atomic_inc(&init_mm.mm_count); | |
6391 | enter_lazy_tlb(&init_mm, current); | |
6392 | ||
6393 | /* | |
6394 | * Make us the idle thread. Technically, schedule() should not be | |
6395 | * called from this thread, however somewhere below it might be, | |
6396 | * but because we are the idle thread, we just pick up running again | |
6397 | * when this runqueue becomes "idle". | |
6398 | */ | |
6399 | init_idle(current, smp_processor_id()); | |
dd41f596 IM |
6400 | /* |
6401 | * During early bootup we pretend to be a normal task: | |
6402 | */ | |
6403 | current->sched_class = &fair_sched_class; | |
1da177e4 LT |
6404 | } |
6405 | ||
6406 | #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP | |
6407 | void __might_sleep(char *file, int line) | |
6408 | { | |
48f24c4d | 6409 | #ifdef in_atomic |
1da177e4 LT |
6410 | static unsigned long prev_jiffy; /* ratelimiting */ |
6411 | ||
6412 | if ((in_atomic() || irqs_disabled()) && | |
6413 | system_state == SYSTEM_RUNNING && !oops_in_progress) { | |
6414 | if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy) | |
6415 | return; | |
6416 | prev_jiffy = jiffies; | |
91368d73 | 6417 | printk(KERN_ERR "BUG: sleeping function called from invalid" |
1da177e4 LT |
6418 | " context at %s:%d\n", file, line); |
6419 | printk("in_atomic():%d, irqs_disabled():%d\n", | |
6420 | in_atomic(), irqs_disabled()); | |
a4c410f0 | 6421 | debug_show_held_locks(current); |
3117df04 IM |
6422 | if (irqs_disabled()) |
6423 | print_irqtrace_events(current); | |
1da177e4 LT |
6424 | dump_stack(); |
6425 | } | |
6426 | #endif | |
6427 | } | |
6428 | EXPORT_SYMBOL(__might_sleep); | |
6429 | #endif | |
6430 | ||
6431 | #ifdef CONFIG_MAGIC_SYSRQ | |
6432 | void normalize_rt_tasks(void) | |
6433 | { | |
a0f98a1c | 6434 | struct task_struct *g, *p; |
1da177e4 | 6435 | unsigned long flags; |
70b97a7f | 6436 | struct rq *rq; |
dd41f596 | 6437 | int on_rq; |
1da177e4 LT |
6438 | |
6439 | read_lock_irq(&tasklist_lock); | |
a0f98a1c | 6440 | do_each_thread(g, p) { |
dd41f596 IM |
6441 | p->se.fair_key = 0; |
6442 | p->se.wait_runtime = 0; | |
6443 | p->se.wait_start_fair = 0; | |
6444 | p->se.wait_start = 0; | |
6445 | p->se.exec_start = 0; | |
6446 | p->se.sleep_start = 0; | |
6447 | p->se.sleep_start_fair = 0; | |
6448 | p->se.block_start = 0; | |
6449 | task_rq(p)->cfs.fair_clock = 0; | |
6450 | task_rq(p)->clock = 0; | |
6451 | ||
6452 | if (!rt_task(p)) { | |
6453 | /* | |
6454 | * Renice negative nice level userspace | |
6455 | * tasks back to 0: | |
6456 | */ | |
6457 | if (TASK_NICE(p) < 0 && p->mm) | |
6458 | set_user_nice(p, 0); | |
1da177e4 | 6459 | continue; |
dd41f596 | 6460 | } |
1da177e4 | 6461 | |
b29739f9 IM |
6462 | spin_lock_irqsave(&p->pi_lock, flags); |
6463 | rq = __task_rq_lock(p); | |
dd41f596 IM |
6464 | #ifdef CONFIG_SMP |
6465 | /* | |
6466 | * Do not touch the migration thread: | |
6467 | */ | |
6468 | if (p == rq->migration_thread) | |
6469 | goto out_unlock; | |
6470 | #endif | |
1da177e4 | 6471 | |
dd41f596 IM |
6472 | on_rq = p->se.on_rq; |
6473 | if (on_rq) | |
6474 | deactivate_task(task_rq(p), p, 0); | |
6475 | __setscheduler(rq, p, SCHED_NORMAL, 0); | |
6476 | if (on_rq) { | |
6477 | activate_task(task_rq(p), p, 0); | |
1da177e4 LT |
6478 | resched_task(rq->curr); |
6479 | } | |
dd41f596 IM |
6480 | #ifdef CONFIG_SMP |
6481 | out_unlock: | |
6482 | #endif | |
b29739f9 IM |
6483 | __task_rq_unlock(rq); |
6484 | spin_unlock_irqrestore(&p->pi_lock, flags); | |
a0f98a1c IM |
6485 | } while_each_thread(g, p); |
6486 | ||
1da177e4 LT |
6487 | read_unlock_irq(&tasklist_lock); |
6488 | } | |
6489 | ||
6490 | #endif /* CONFIG_MAGIC_SYSRQ */ | |
1df5c10a LT |
6491 | |
6492 | #ifdef CONFIG_IA64 | |
6493 | /* | |
6494 | * These functions are only useful for the IA64 MCA handling. | |
6495 | * | |
6496 | * They can only be called when the whole system has been | |
6497 | * stopped - every CPU needs to be quiescent, and no scheduling | |
6498 | * activity can take place. Using them for anything else would | |
6499 | * be a serious bug, and as a result, they aren't even visible | |
6500 | * under any other configuration. | |
6501 | */ | |
6502 | ||
6503 | /** | |
6504 | * curr_task - return the current task for a given cpu. | |
6505 | * @cpu: the processor in question. | |
6506 | * | |
6507 | * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! | |
6508 | */ | |
36c8b586 | 6509 | struct task_struct *curr_task(int cpu) |
1df5c10a LT |
6510 | { |
6511 | return cpu_curr(cpu); | |
6512 | } | |
6513 | ||
6514 | /** | |
6515 | * set_curr_task - set the current task for a given cpu. | |
6516 | * @cpu: the processor in question. | |
6517 | * @p: the task pointer to set. | |
6518 | * | |
6519 | * Description: This function must only be used when non-maskable interrupts | |
6520 | * are serviced on a separate stack. It allows the architecture to switch the | |
6521 | * notion of the current task on a cpu in a non-blocking manner. This function | |
6522 | * must be called with all CPU's synchronized, and interrupts disabled, the | |
6523 | * and caller must save the original value of the current task (see | |
6524 | * curr_task() above) and restore that value before reenabling interrupts and | |
6525 | * re-starting the system. | |
6526 | * | |
6527 | * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! | |
6528 | */ | |
36c8b586 | 6529 | void set_curr_task(int cpu, struct task_struct *p) |
1df5c10a LT |
6530 | { |
6531 | cpu_curr(cpu) = p; | |
6532 | } | |
6533 | ||
6534 | #endif |