Commit | Line | Data |
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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 | |
c31f2e8a IM |
19 | * 2007-04-15 Work begun on replacing all interactivity tuning with a |
20 | * fair scheduling design by Con Kolivas. | |
21 | * 2007-05-05 Load balancing (smp-nice) and other improvements | |
22 | * by Peter Williams | |
23 | * 2007-05-06 Interactivity improvements to CFS by Mike Galbraith | |
24 | * 2007-07-01 Group scheduling enhancements by Srivatsa Vaddagiri | |
1da177e4 LT |
25 | */ |
26 | ||
27 | #include <linux/mm.h> | |
28 | #include <linux/module.h> | |
29 | #include <linux/nmi.h> | |
30 | #include <linux/init.h> | |
dff06c15 | 31 | #include <linux/uaccess.h> |
1da177e4 LT |
32 | #include <linux/highmem.h> |
33 | #include <linux/smp_lock.h> | |
34 | #include <asm/mmu_context.h> | |
35 | #include <linux/interrupt.h> | |
c59ede7b | 36 | #include <linux/capability.h> |
1da177e4 LT |
37 | #include <linux/completion.h> |
38 | #include <linux/kernel_stat.h> | |
9a11b49a | 39 | #include <linux/debug_locks.h> |
1da177e4 LT |
40 | #include <linux/security.h> |
41 | #include <linux/notifier.h> | |
42 | #include <linux/profile.h> | |
7dfb7103 | 43 | #include <linux/freezer.h> |
198e2f18 | 44 | #include <linux/vmalloc.h> |
1da177e4 LT |
45 | #include <linux/blkdev.h> |
46 | #include <linux/delay.h> | |
47 | #include <linux/smp.h> | |
48 | #include <linux/threads.h> | |
49 | #include <linux/timer.h> | |
50 | #include <linux/rcupdate.h> | |
51 | #include <linux/cpu.h> | |
52 | #include <linux/cpuset.h> | |
53 | #include <linux/percpu.h> | |
54 | #include <linux/kthread.h> | |
55 | #include <linux/seq_file.h> | |
e692ab53 | 56 | #include <linux/sysctl.h> |
1da177e4 LT |
57 | #include <linux/syscalls.h> |
58 | #include <linux/times.h> | |
8f0ab514 | 59 | #include <linux/tsacct_kern.h> |
c6fd91f0 | 60 | #include <linux/kprobes.h> |
0ff92245 | 61 | #include <linux/delayacct.h> |
5517d86b | 62 | #include <linux/reciprocal_div.h> |
dff06c15 | 63 | #include <linux/unistd.h> |
1da177e4 | 64 | |
5517d86b | 65 | #include <asm/tlb.h> |
1da177e4 | 66 | |
b035b6de AD |
67 | /* |
68 | * Scheduler clock - returns current time in nanosec units. | |
69 | * This is default implementation. | |
70 | * Architectures and sub-architectures can override this. | |
71 | */ | |
72 | unsigned long long __attribute__((weak)) sched_clock(void) | |
73 | { | |
74 | return (unsigned long long)jiffies * (1000000000 / HZ); | |
75 | } | |
76 | ||
1da177e4 LT |
77 | /* |
78 | * Convert user-nice values [ -20 ... 0 ... 19 ] | |
79 | * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ], | |
80 | * and back. | |
81 | */ | |
82 | #define NICE_TO_PRIO(nice) (MAX_RT_PRIO + (nice) + 20) | |
83 | #define PRIO_TO_NICE(prio) ((prio) - MAX_RT_PRIO - 20) | |
84 | #define TASK_NICE(p) PRIO_TO_NICE((p)->static_prio) | |
85 | ||
86 | /* | |
87 | * 'User priority' is the nice value converted to something we | |
88 | * can work with better when scaling various scheduler parameters, | |
89 | * it's a [ 0 ... 39 ] range. | |
90 | */ | |
91 | #define USER_PRIO(p) ((p)-MAX_RT_PRIO) | |
92 | #define TASK_USER_PRIO(p) USER_PRIO((p)->static_prio) | |
93 | #define MAX_USER_PRIO (USER_PRIO(MAX_PRIO)) | |
94 | ||
95 | /* | |
96 | * Some helpers for converting nanosecond timing to jiffy resolution | |
97 | */ | |
98 | #define NS_TO_JIFFIES(TIME) ((TIME) / (1000000000 / HZ)) | |
99 | #define JIFFIES_TO_NS(TIME) ((TIME) * (1000000000 / HZ)) | |
100 | ||
6aa645ea IM |
101 | #define NICE_0_LOAD SCHED_LOAD_SCALE |
102 | #define NICE_0_SHIFT SCHED_LOAD_SHIFT | |
103 | ||
1da177e4 LT |
104 | /* |
105 | * These are the 'tuning knobs' of the scheduler: | |
106 | * | |
107 | * Minimum timeslice is 5 msecs (or 1 jiffy, whichever is larger), | |
108 | * default timeslice is 100 msecs, maximum timeslice is 800 msecs. | |
109 | * Timeslices get refilled after they expire. | |
110 | */ | |
111 | #define MIN_TIMESLICE max(5 * HZ / 1000, 1) | |
112 | #define DEF_TIMESLICE (100 * HZ / 1000) | |
2dd73a4f | 113 | |
5517d86b ED |
114 | #ifdef CONFIG_SMP |
115 | /* | |
116 | * Divide a load by a sched group cpu_power : (load / sg->__cpu_power) | |
117 | * Since cpu_power is a 'constant', we can use a reciprocal divide. | |
118 | */ | |
119 | static inline u32 sg_div_cpu_power(const struct sched_group *sg, u32 load) | |
120 | { | |
121 | return reciprocal_divide(load, sg->reciprocal_cpu_power); | |
122 | } | |
123 | ||
124 | /* | |
125 | * Each time a sched group cpu_power is changed, | |
126 | * we must compute its reciprocal value | |
127 | */ | |
128 | static inline void sg_inc_cpu_power(struct sched_group *sg, u32 val) | |
129 | { | |
130 | sg->__cpu_power += val; | |
131 | sg->reciprocal_cpu_power = reciprocal_value(sg->__cpu_power); | |
132 | } | |
133 | #endif | |
134 | ||
634fa8c9 IM |
135 | #define SCALE_PRIO(x, prio) \ |
136 | max(x * (MAX_PRIO - prio) / (MAX_USER_PRIO / 2), MIN_TIMESLICE) | |
137 | ||
91fcdd4e | 138 | /* |
634fa8c9 | 139 | * static_prio_timeslice() scales user-nice values [ -20 ... 0 ... 19 ] |
91fcdd4e | 140 | * to time slice values: [800ms ... 100ms ... 5ms] |
91fcdd4e | 141 | */ |
634fa8c9 | 142 | static unsigned int static_prio_timeslice(int static_prio) |
2dd73a4f | 143 | { |
634fa8c9 IM |
144 | if (static_prio == NICE_TO_PRIO(19)) |
145 | return 1; | |
146 | ||
147 | if (static_prio < NICE_TO_PRIO(0)) | |
148 | return SCALE_PRIO(DEF_TIMESLICE * 4, static_prio); | |
149 | else | |
150 | return SCALE_PRIO(DEF_TIMESLICE, static_prio); | |
2dd73a4f PW |
151 | } |
152 | ||
e05606d3 IM |
153 | static inline int rt_policy(int policy) |
154 | { | |
155 | if (unlikely(policy == SCHED_FIFO) || unlikely(policy == SCHED_RR)) | |
156 | return 1; | |
157 | return 0; | |
158 | } | |
159 | ||
160 | static inline int task_has_rt_policy(struct task_struct *p) | |
161 | { | |
162 | return rt_policy(p->policy); | |
163 | } | |
164 | ||
1da177e4 | 165 | /* |
6aa645ea | 166 | * This is the priority-queue data structure of the RT scheduling class: |
1da177e4 | 167 | */ |
6aa645ea IM |
168 | struct rt_prio_array { |
169 | DECLARE_BITMAP(bitmap, MAX_RT_PRIO+1); /* include 1 bit for delimiter */ | |
170 | struct list_head queue[MAX_RT_PRIO]; | |
171 | }; | |
172 | ||
173 | struct load_stat { | |
174 | struct load_weight load; | |
175 | u64 load_update_start, load_update_last; | |
176 | unsigned long delta_fair, delta_exec, delta_stat; | |
177 | }; | |
178 | ||
179 | /* CFS-related fields in a runqueue */ | |
180 | struct cfs_rq { | |
181 | struct load_weight load; | |
182 | unsigned long nr_running; | |
183 | ||
184 | s64 fair_clock; | |
185 | u64 exec_clock; | |
186 | s64 wait_runtime; | |
187 | u64 sleeper_bonus; | |
188 | unsigned long wait_runtime_overruns, wait_runtime_underruns; | |
189 | ||
190 | struct rb_root tasks_timeline; | |
191 | struct rb_node *rb_leftmost; | |
192 | struct rb_node *rb_load_balance_curr; | |
193 | #ifdef CONFIG_FAIR_GROUP_SCHED | |
194 | /* 'curr' points to currently running entity on this cfs_rq. | |
195 | * It is set to NULL otherwise (i.e when none are currently running). | |
196 | */ | |
197 | struct sched_entity *curr; | |
198 | struct rq *rq; /* cpu runqueue to which this cfs_rq is attached */ | |
199 | ||
200 | /* leaf cfs_rqs are those that hold tasks (lowest schedulable entity in | |
201 | * a hierarchy). Non-leaf lrqs hold other higher schedulable entities | |
202 | * (like users, containers etc.) | |
203 | * | |
204 | * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This | |
205 | * list is used during load balance. | |
206 | */ | |
207 | struct list_head leaf_cfs_rq_list; /* Better name : task_cfs_rq_list? */ | |
208 | #endif | |
209 | }; | |
1da177e4 | 210 | |
6aa645ea IM |
211 | /* Real-Time classes' related field in a runqueue: */ |
212 | struct rt_rq { | |
213 | struct rt_prio_array active; | |
214 | int rt_load_balance_idx; | |
215 | struct list_head *rt_load_balance_head, *rt_load_balance_curr; | |
216 | }; | |
217 | ||
1da177e4 LT |
218 | /* |
219 | * This is the main, per-CPU runqueue data structure. | |
220 | * | |
221 | * Locking rule: those places that want to lock multiple runqueues | |
222 | * (such as the load balancing or the thread migration code), lock | |
223 | * acquire operations must be ordered by ascending &runqueue. | |
224 | */ | |
70b97a7f | 225 | struct rq { |
6aa645ea | 226 | spinlock_t lock; /* runqueue lock */ |
1da177e4 LT |
227 | |
228 | /* | |
229 | * nr_running and cpu_load should be in the same cacheline because | |
230 | * remote CPUs use both these fields when doing load calculation. | |
231 | */ | |
232 | unsigned long nr_running; | |
6aa645ea IM |
233 | #define CPU_LOAD_IDX_MAX 5 |
234 | unsigned long cpu_load[CPU_LOAD_IDX_MAX]; | |
bdecea3a | 235 | unsigned char idle_at_tick; |
46cb4b7c SS |
236 | #ifdef CONFIG_NO_HZ |
237 | unsigned char in_nohz_recently; | |
238 | #endif | |
6aa645ea IM |
239 | struct load_stat ls; /* capture load from *all* tasks on this cpu */ |
240 | unsigned long nr_load_updates; | |
241 | u64 nr_switches; | |
242 | ||
243 | struct cfs_rq cfs; | |
244 | #ifdef CONFIG_FAIR_GROUP_SCHED | |
245 | struct list_head leaf_cfs_rq_list; /* list of leaf cfs_rq on this cpu */ | |
1da177e4 | 246 | #endif |
6aa645ea | 247 | struct rt_rq rt; |
1da177e4 LT |
248 | |
249 | /* | |
250 | * This is part of a global counter where only the total sum | |
251 | * over all CPUs matters. A task can increase this counter on | |
252 | * one CPU and if it got migrated afterwards it may decrease | |
253 | * it on another CPU. Always updated under the runqueue lock: | |
254 | */ | |
255 | unsigned long nr_uninterruptible; | |
256 | ||
36c8b586 | 257 | struct task_struct *curr, *idle; |
c9819f45 | 258 | unsigned long next_balance; |
1da177e4 | 259 | struct mm_struct *prev_mm; |
6aa645ea | 260 | |
6aa645ea IM |
261 | u64 clock, prev_clock_raw; |
262 | s64 clock_max_delta; | |
263 | ||
264 | unsigned int clock_warps, clock_overflows; | |
2aa44d05 IM |
265 | u64 idle_clock; |
266 | unsigned int clock_deep_idle_events; | |
529c7726 | 267 | u64 tick_timestamp; |
6aa645ea | 268 | |
1da177e4 LT |
269 | atomic_t nr_iowait; |
270 | ||
271 | #ifdef CONFIG_SMP | |
272 | struct sched_domain *sd; | |
273 | ||
274 | /* For active balancing */ | |
275 | int active_balance; | |
276 | int push_cpu; | |
0a2966b4 | 277 | int cpu; /* cpu of this runqueue */ |
1da177e4 | 278 | |
36c8b586 | 279 | struct task_struct *migration_thread; |
1da177e4 LT |
280 | struct list_head migration_queue; |
281 | #endif | |
282 | ||
283 | #ifdef CONFIG_SCHEDSTATS | |
284 | /* latency stats */ | |
285 | struct sched_info rq_sched_info; | |
286 | ||
287 | /* sys_sched_yield() stats */ | |
288 | unsigned long yld_exp_empty; | |
289 | unsigned long yld_act_empty; | |
290 | unsigned long yld_both_empty; | |
291 | unsigned long yld_cnt; | |
292 | ||
293 | /* schedule() stats */ | |
294 | unsigned long sched_switch; | |
295 | unsigned long sched_cnt; | |
296 | unsigned long sched_goidle; | |
297 | ||
298 | /* try_to_wake_up() stats */ | |
299 | unsigned long ttwu_cnt; | |
300 | unsigned long ttwu_local; | |
301 | #endif | |
fcb99371 | 302 | struct lock_class_key rq_lock_key; |
1da177e4 LT |
303 | }; |
304 | ||
f34e3b61 | 305 | static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues); |
5be9361c | 306 | static DEFINE_MUTEX(sched_hotcpu_mutex); |
1da177e4 | 307 | |
dd41f596 IM |
308 | static inline void check_preempt_curr(struct rq *rq, struct task_struct *p) |
309 | { | |
310 | rq->curr->sched_class->check_preempt_curr(rq, p); | |
311 | } | |
312 | ||
0a2966b4 CL |
313 | static inline int cpu_of(struct rq *rq) |
314 | { | |
315 | #ifdef CONFIG_SMP | |
316 | return rq->cpu; | |
317 | #else | |
318 | return 0; | |
319 | #endif | |
320 | } | |
321 | ||
20d315d4 | 322 | /* |
b04a0f4c IM |
323 | * Update the per-runqueue clock, as finegrained as the platform can give |
324 | * us, but without assuming monotonicity, etc.: | |
20d315d4 | 325 | */ |
b04a0f4c | 326 | static void __update_rq_clock(struct rq *rq) |
20d315d4 IM |
327 | { |
328 | u64 prev_raw = rq->prev_clock_raw; | |
329 | u64 now = sched_clock(); | |
330 | s64 delta = now - prev_raw; | |
331 | u64 clock = rq->clock; | |
332 | ||
b04a0f4c IM |
333 | #ifdef CONFIG_SCHED_DEBUG |
334 | WARN_ON_ONCE(cpu_of(rq) != smp_processor_id()); | |
335 | #endif | |
20d315d4 IM |
336 | /* |
337 | * Protect against sched_clock() occasionally going backwards: | |
338 | */ | |
339 | if (unlikely(delta < 0)) { | |
340 | clock++; | |
341 | rq->clock_warps++; | |
342 | } else { | |
343 | /* | |
344 | * Catch too large forward jumps too: | |
345 | */ | |
529c7726 IM |
346 | if (unlikely(clock + delta > rq->tick_timestamp + TICK_NSEC)) { |
347 | if (clock < rq->tick_timestamp + TICK_NSEC) | |
348 | clock = rq->tick_timestamp + TICK_NSEC; | |
349 | else | |
350 | clock++; | |
20d315d4 IM |
351 | rq->clock_overflows++; |
352 | } else { | |
353 | if (unlikely(delta > rq->clock_max_delta)) | |
354 | rq->clock_max_delta = delta; | |
355 | clock += delta; | |
356 | } | |
357 | } | |
358 | ||
359 | rq->prev_clock_raw = now; | |
360 | rq->clock = clock; | |
b04a0f4c | 361 | } |
20d315d4 | 362 | |
b04a0f4c IM |
363 | static void update_rq_clock(struct rq *rq) |
364 | { | |
365 | if (likely(smp_processor_id() == cpu_of(rq))) | |
366 | __update_rq_clock(rq); | |
20d315d4 IM |
367 | } |
368 | ||
674311d5 NP |
369 | /* |
370 | * The domain tree (rq->sd) is protected by RCU's quiescent state transition. | |
1a20ff27 | 371 | * See detach_destroy_domains: synchronize_sched for details. |
674311d5 NP |
372 | * |
373 | * The domain tree of any CPU may only be accessed from within | |
374 | * preempt-disabled sections. | |
375 | */ | |
48f24c4d IM |
376 | #define for_each_domain(cpu, __sd) \ |
377 | for (__sd = rcu_dereference(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent) | |
1da177e4 LT |
378 | |
379 | #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu))) | |
380 | #define this_rq() (&__get_cpu_var(runqueues)) | |
381 | #define task_rq(p) cpu_rq(task_cpu(p)) | |
382 | #define cpu_curr(cpu) (cpu_rq(cpu)->curr) | |
383 | ||
e436d800 IM |
384 | /* |
385 | * For kernel-internal use: high-speed (but slightly incorrect) per-cpu | |
386 | * clock constructed from sched_clock(): | |
387 | */ | |
388 | unsigned long long cpu_clock(int cpu) | |
389 | { | |
e436d800 IM |
390 | unsigned long long now; |
391 | unsigned long flags; | |
b04a0f4c | 392 | struct rq *rq; |
e436d800 | 393 | |
2cd4d0ea | 394 | local_irq_save(flags); |
b04a0f4c IM |
395 | rq = cpu_rq(cpu); |
396 | update_rq_clock(rq); | |
397 | now = rq->clock; | |
2cd4d0ea | 398 | local_irq_restore(flags); |
e436d800 IM |
399 | |
400 | return now; | |
401 | } | |
402 | ||
138a8aeb IM |
403 | #ifdef CONFIG_FAIR_GROUP_SCHED |
404 | /* Change a task's ->cfs_rq if it moves across CPUs */ | |
405 | static inline void set_task_cfs_rq(struct task_struct *p) | |
406 | { | |
407 | p->se.cfs_rq = &task_rq(p)->cfs; | |
408 | } | |
409 | #else | |
410 | static inline void set_task_cfs_rq(struct task_struct *p) | |
411 | { | |
412 | } | |
413 | #endif | |
414 | ||
1da177e4 | 415 | #ifndef prepare_arch_switch |
4866cde0 NP |
416 | # define prepare_arch_switch(next) do { } while (0) |
417 | #endif | |
418 | #ifndef finish_arch_switch | |
419 | # define finish_arch_switch(prev) do { } while (0) | |
420 | #endif | |
421 | ||
422 | #ifndef __ARCH_WANT_UNLOCKED_CTXSW | |
70b97a7f | 423 | static inline int task_running(struct rq *rq, struct task_struct *p) |
4866cde0 NP |
424 | { |
425 | return rq->curr == p; | |
426 | } | |
427 | ||
70b97a7f | 428 | static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next) |
4866cde0 NP |
429 | { |
430 | } | |
431 | ||
70b97a7f | 432 | static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev) |
4866cde0 | 433 | { |
da04c035 IM |
434 | #ifdef CONFIG_DEBUG_SPINLOCK |
435 | /* this is a valid case when another task releases the spinlock */ | |
436 | rq->lock.owner = current; | |
437 | #endif | |
8a25d5de IM |
438 | /* |
439 | * If we are tracking spinlock dependencies then we have to | |
440 | * fix up the runqueue lock - which gets 'carried over' from | |
441 | * prev into current: | |
442 | */ | |
443 | spin_acquire(&rq->lock.dep_map, 0, 0, _THIS_IP_); | |
444 | ||
4866cde0 NP |
445 | spin_unlock_irq(&rq->lock); |
446 | } | |
447 | ||
448 | #else /* __ARCH_WANT_UNLOCKED_CTXSW */ | |
70b97a7f | 449 | static inline int task_running(struct rq *rq, struct task_struct *p) |
4866cde0 NP |
450 | { |
451 | #ifdef CONFIG_SMP | |
452 | return p->oncpu; | |
453 | #else | |
454 | return rq->curr == p; | |
455 | #endif | |
456 | } | |
457 | ||
70b97a7f | 458 | static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next) |
4866cde0 NP |
459 | { |
460 | #ifdef CONFIG_SMP | |
461 | /* | |
462 | * We can optimise this out completely for !SMP, because the | |
463 | * SMP rebalancing from interrupt is the only thing that cares | |
464 | * here. | |
465 | */ | |
466 | next->oncpu = 1; | |
467 | #endif | |
468 | #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW | |
469 | spin_unlock_irq(&rq->lock); | |
470 | #else | |
471 | spin_unlock(&rq->lock); | |
472 | #endif | |
473 | } | |
474 | ||
70b97a7f | 475 | static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev) |
4866cde0 NP |
476 | { |
477 | #ifdef CONFIG_SMP | |
478 | /* | |
479 | * After ->oncpu is cleared, the task can be moved to a different CPU. | |
480 | * We must ensure this doesn't happen until the switch is completely | |
481 | * finished. | |
482 | */ | |
483 | smp_wmb(); | |
484 | prev->oncpu = 0; | |
485 | #endif | |
486 | #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW | |
487 | local_irq_enable(); | |
1da177e4 | 488 | #endif |
4866cde0 NP |
489 | } |
490 | #endif /* __ARCH_WANT_UNLOCKED_CTXSW */ | |
1da177e4 | 491 | |
b29739f9 IM |
492 | /* |
493 | * __task_rq_lock - lock the runqueue a given task resides on. | |
494 | * Must be called interrupts disabled. | |
495 | */ | |
70b97a7f | 496 | static inline struct rq *__task_rq_lock(struct task_struct *p) |
b29739f9 IM |
497 | __acquires(rq->lock) |
498 | { | |
70b97a7f | 499 | struct rq *rq; |
b29739f9 IM |
500 | |
501 | repeat_lock_task: | |
502 | rq = task_rq(p); | |
503 | spin_lock(&rq->lock); | |
504 | if (unlikely(rq != task_rq(p))) { | |
505 | spin_unlock(&rq->lock); | |
506 | goto repeat_lock_task; | |
507 | } | |
508 | return rq; | |
509 | } | |
510 | ||
1da177e4 LT |
511 | /* |
512 | * task_rq_lock - lock the runqueue a given task resides on and disable | |
513 | * interrupts. Note the ordering: we can safely lookup the task_rq without | |
514 | * explicitly disabling preemption. | |
515 | */ | |
70b97a7f | 516 | static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags) |
1da177e4 LT |
517 | __acquires(rq->lock) |
518 | { | |
70b97a7f | 519 | struct rq *rq; |
1da177e4 LT |
520 | |
521 | repeat_lock_task: | |
522 | local_irq_save(*flags); | |
523 | rq = task_rq(p); | |
524 | spin_lock(&rq->lock); | |
525 | if (unlikely(rq != task_rq(p))) { | |
526 | spin_unlock_irqrestore(&rq->lock, *flags); | |
527 | goto repeat_lock_task; | |
528 | } | |
529 | return rq; | |
530 | } | |
531 | ||
70b97a7f | 532 | static inline void __task_rq_unlock(struct rq *rq) |
b29739f9 IM |
533 | __releases(rq->lock) |
534 | { | |
535 | spin_unlock(&rq->lock); | |
536 | } | |
537 | ||
70b97a7f | 538 | static inline void task_rq_unlock(struct rq *rq, unsigned long *flags) |
1da177e4 LT |
539 | __releases(rq->lock) |
540 | { | |
541 | spin_unlock_irqrestore(&rq->lock, *flags); | |
542 | } | |
543 | ||
1da177e4 | 544 | /* |
cc2a73b5 | 545 | * this_rq_lock - lock this runqueue and disable interrupts. |
1da177e4 | 546 | */ |
70b97a7f | 547 | static inline struct rq *this_rq_lock(void) |
1da177e4 LT |
548 | __acquires(rq->lock) |
549 | { | |
70b97a7f | 550 | struct rq *rq; |
1da177e4 LT |
551 | |
552 | local_irq_disable(); | |
553 | rq = this_rq(); | |
554 | spin_lock(&rq->lock); | |
555 | ||
556 | return rq; | |
557 | } | |
558 | ||
1b9f19c2 | 559 | /* |
2aa44d05 | 560 | * We are going deep-idle (irqs are disabled): |
1b9f19c2 | 561 | */ |
2aa44d05 | 562 | void sched_clock_idle_sleep_event(void) |
1b9f19c2 | 563 | { |
2aa44d05 IM |
564 | struct rq *rq = cpu_rq(smp_processor_id()); |
565 | ||
566 | spin_lock(&rq->lock); | |
567 | __update_rq_clock(rq); | |
568 | spin_unlock(&rq->lock); | |
569 | rq->clock_deep_idle_events++; | |
570 | } | |
571 | EXPORT_SYMBOL_GPL(sched_clock_idle_sleep_event); | |
572 | ||
573 | /* | |
574 | * We just idled delta nanoseconds (called with irqs disabled): | |
575 | */ | |
576 | void sched_clock_idle_wakeup_event(u64 delta_ns) | |
577 | { | |
578 | struct rq *rq = cpu_rq(smp_processor_id()); | |
579 | u64 now = sched_clock(); | |
1b9f19c2 | 580 | |
2aa44d05 IM |
581 | rq->idle_clock += delta_ns; |
582 | /* | |
583 | * Override the previous timestamp and ignore all | |
584 | * sched_clock() deltas that occured while we idled, | |
585 | * and use the PM-provided delta_ns to advance the | |
586 | * rq clock: | |
587 | */ | |
588 | spin_lock(&rq->lock); | |
589 | rq->prev_clock_raw = now; | |
590 | rq->clock += delta_ns; | |
591 | spin_unlock(&rq->lock); | |
1b9f19c2 | 592 | } |
2aa44d05 | 593 | EXPORT_SYMBOL_GPL(sched_clock_idle_wakeup_event); |
1b9f19c2 | 594 | |
c24d20db IM |
595 | /* |
596 | * resched_task - mark a task 'to be rescheduled now'. | |
597 | * | |
598 | * On UP this means the setting of the need_resched flag, on SMP it | |
599 | * might also involve a cross-CPU call to trigger the scheduler on | |
600 | * the target CPU. | |
601 | */ | |
602 | #ifdef CONFIG_SMP | |
603 | ||
604 | #ifndef tsk_is_polling | |
605 | #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG) | |
606 | #endif | |
607 | ||
608 | static void resched_task(struct task_struct *p) | |
609 | { | |
610 | int cpu; | |
611 | ||
612 | assert_spin_locked(&task_rq(p)->lock); | |
613 | ||
614 | if (unlikely(test_tsk_thread_flag(p, TIF_NEED_RESCHED))) | |
615 | return; | |
616 | ||
617 | set_tsk_thread_flag(p, TIF_NEED_RESCHED); | |
618 | ||
619 | cpu = task_cpu(p); | |
620 | if (cpu == smp_processor_id()) | |
621 | return; | |
622 | ||
623 | /* NEED_RESCHED must be visible before we test polling */ | |
624 | smp_mb(); | |
625 | if (!tsk_is_polling(p)) | |
626 | smp_send_reschedule(cpu); | |
627 | } | |
628 | ||
629 | static void resched_cpu(int cpu) | |
630 | { | |
631 | struct rq *rq = cpu_rq(cpu); | |
632 | unsigned long flags; | |
633 | ||
634 | if (!spin_trylock_irqsave(&rq->lock, flags)) | |
635 | return; | |
636 | resched_task(cpu_curr(cpu)); | |
637 | spin_unlock_irqrestore(&rq->lock, flags); | |
638 | } | |
639 | #else | |
640 | static inline void resched_task(struct task_struct *p) | |
641 | { | |
642 | assert_spin_locked(&task_rq(p)->lock); | |
643 | set_tsk_need_resched(p); | |
644 | } | |
645 | #endif | |
646 | ||
45bf76df IM |
647 | static u64 div64_likely32(u64 divident, unsigned long divisor) |
648 | { | |
649 | #if BITS_PER_LONG == 32 | |
650 | if (likely(divident <= 0xffffffffULL)) | |
651 | return (u32)divident / divisor; | |
652 | do_div(divident, divisor); | |
653 | ||
654 | return divident; | |
655 | #else | |
656 | return divident / divisor; | |
657 | #endif | |
658 | } | |
659 | ||
660 | #if BITS_PER_LONG == 32 | |
661 | # define WMULT_CONST (~0UL) | |
662 | #else | |
663 | # define WMULT_CONST (1UL << 32) | |
664 | #endif | |
665 | ||
666 | #define WMULT_SHIFT 32 | |
667 | ||
194081eb IM |
668 | /* |
669 | * Shift right and round: | |
670 | */ | |
671 | #define RSR(x, y) (((x) + (1UL << ((y) - 1))) >> (y)) | |
672 | ||
cb1c4fc9 | 673 | static unsigned long |
45bf76df IM |
674 | calc_delta_mine(unsigned long delta_exec, unsigned long weight, |
675 | struct load_weight *lw) | |
676 | { | |
677 | u64 tmp; | |
678 | ||
679 | if (unlikely(!lw->inv_weight)) | |
194081eb | 680 | lw->inv_weight = (WMULT_CONST - lw->weight/2) / lw->weight + 1; |
45bf76df IM |
681 | |
682 | tmp = (u64)delta_exec * weight; | |
683 | /* | |
684 | * Check whether we'd overflow the 64-bit multiplication: | |
685 | */ | |
194081eb IM |
686 | if (unlikely(tmp > WMULT_CONST)) |
687 | tmp = RSR(RSR(tmp, WMULT_SHIFT/2) * lw->inv_weight, | |
688 | WMULT_SHIFT/2); | |
689 | else | |
690 | tmp = RSR(tmp * lw->inv_weight, WMULT_SHIFT); | |
45bf76df | 691 | |
ecf691da | 692 | return (unsigned long)min(tmp, (u64)(unsigned long)LONG_MAX); |
45bf76df IM |
693 | } |
694 | ||
695 | static inline unsigned long | |
696 | calc_delta_fair(unsigned long delta_exec, struct load_weight *lw) | |
697 | { | |
698 | return calc_delta_mine(delta_exec, NICE_0_LOAD, lw); | |
699 | } | |
700 | ||
701 | static void update_load_add(struct load_weight *lw, unsigned long inc) | |
702 | { | |
703 | lw->weight += inc; | |
704 | lw->inv_weight = 0; | |
705 | } | |
706 | ||
707 | static void update_load_sub(struct load_weight *lw, unsigned long dec) | |
708 | { | |
709 | lw->weight -= dec; | |
710 | lw->inv_weight = 0; | |
711 | } | |
712 | ||
2dd73a4f PW |
713 | /* |
714 | * To aid in avoiding the subversion of "niceness" due to uneven distribution | |
715 | * of tasks with abnormal "nice" values across CPUs the contribution that | |
716 | * each task makes to its run queue's load is weighted according to its | |
717 | * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a | |
718 | * scaled version of the new time slice allocation that they receive on time | |
719 | * slice expiry etc. | |
720 | */ | |
721 | ||
dd41f596 IM |
722 | #define WEIGHT_IDLEPRIO 2 |
723 | #define WMULT_IDLEPRIO (1 << 31) | |
724 | ||
725 | /* | |
726 | * Nice levels are multiplicative, with a gentle 10% change for every | |
727 | * nice level changed. I.e. when a CPU-bound task goes from nice 0 to | |
728 | * nice 1, it will get ~10% less CPU time than another CPU-bound task | |
729 | * that remained on nice 0. | |
730 | * | |
731 | * The "10% effect" is relative and cumulative: from _any_ nice level, | |
732 | * if you go up 1 level, it's -10% CPU usage, if you go down 1 level | |
f9153ee6 IM |
733 | * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25. |
734 | * If a task goes up by ~10% and another task goes down by ~10% then | |
735 | * the relative distance between them is ~25%.) | |
dd41f596 IM |
736 | */ |
737 | static const int prio_to_weight[40] = { | |
254753dc IM |
738 | /* -20 */ 88761, 71755, 56483, 46273, 36291, |
739 | /* -15 */ 29154, 23254, 18705, 14949, 11916, | |
740 | /* -10 */ 9548, 7620, 6100, 4904, 3906, | |
741 | /* -5 */ 3121, 2501, 1991, 1586, 1277, | |
742 | /* 0 */ 1024, 820, 655, 526, 423, | |
743 | /* 5 */ 335, 272, 215, 172, 137, | |
744 | /* 10 */ 110, 87, 70, 56, 45, | |
745 | /* 15 */ 36, 29, 23, 18, 15, | |
dd41f596 IM |
746 | }; |
747 | ||
5714d2de IM |
748 | /* |
749 | * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated. | |
750 | * | |
751 | * In cases where the weight does not change often, we can use the | |
752 | * precalculated inverse to speed up arithmetics by turning divisions | |
753 | * into multiplications: | |
754 | */ | |
dd41f596 | 755 | static const u32 prio_to_wmult[40] = { |
254753dc IM |
756 | /* -20 */ 48388, 59856, 76040, 92818, 118348, |
757 | /* -15 */ 147320, 184698, 229616, 287308, 360437, | |
758 | /* -10 */ 449829, 563644, 704093, 875809, 1099582, | |
759 | /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326, | |
760 | /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587, | |
761 | /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126, | |
762 | /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717, | |
763 | /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153, | |
dd41f596 | 764 | }; |
2dd73a4f | 765 | |
dd41f596 IM |
766 | static void activate_task(struct rq *rq, struct task_struct *p, int wakeup); |
767 | ||
768 | /* | |
769 | * runqueue iterator, to support SMP load-balancing between different | |
770 | * scheduling classes, without having to expose their internal data | |
771 | * structures to the load-balancing proper: | |
772 | */ | |
773 | struct rq_iterator { | |
774 | void *arg; | |
775 | struct task_struct *(*start)(void *); | |
776 | struct task_struct *(*next)(void *); | |
777 | }; | |
778 | ||
779 | static int balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
780 | unsigned long max_nr_move, unsigned long max_load_move, | |
781 | struct sched_domain *sd, enum cpu_idle_type idle, | |
782 | int *all_pinned, unsigned long *load_moved, | |
a4ac01c3 | 783 | int *this_best_prio, struct rq_iterator *iterator); |
dd41f596 IM |
784 | |
785 | #include "sched_stats.h" | |
786 | #include "sched_rt.c" | |
787 | #include "sched_fair.c" | |
788 | #include "sched_idletask.c" | |
789 | #ifdef CONFIG_SCHED_DEBUG | |
790 | # include "sched_debug.c" | |
791 | #endif | |
792 | ||
793 | #define sched_class_highest (&rt_sched_class) | |
794 | ||
9c217245 IM |
795 | static void __update_curr_load(struct rq *rq, struct load_stat *ls) |
796 | { | |
797 | if (rq->curr != rq->idle && ls->load.weight) { | |
798 | ls->delta_exec += ls->delta_stat; | |
799 | ls->delta_fair += calc_delta_fair(ls->delta_stat, &ls->load); | |
800 | ls->delta_stat = 0; | |
801 | } | |
802 | } | |
803 | ||
804 | /* | |
805 | * Update delta_exec, delta_fair fields for rq. | |
806 | * | |
807 | * delta_fair clock advances at a rate inversely proportional to | |
808 | * total load (rq->ls.load.weight) on the runqueue, while | |
809 | * delta_exec advances at the same rate as wall-clock (provided | |
810 | * cpu is not idle). | |
811 | * | |
812 | * delta_exec / delta_fair is a measure of the (smoothened) load on this | |
813 | * runqueue over any given interval. This (smoothened) load is used | |
814 | * during load balance. | |
815 | * | |
816 | * This function is called /before/ updating rq->ls.load | |
817 | * and when switching tasks. | |
818 | */ | |
84a1d7a2 | 819 | static void update_curr_load(struct rq *rq) |
9c217245 IM |
820 | { |
821 | struct load_stat *ls = &rq->ls; | |
822 | u64 start; | |
823 | ||
824 | start = ls->load_update_start; | |
d281918d IM |
825 | ls->load_update_start = rq->clock; |
826 | ls->delta_stat += rq->clock - start; | |
9c217245 IM |
827 | /* |
828 | * Stagger updates to ls->delta_fair. Very frequent updates | |
829 | * can be expensive. | |
830 | */ | |
831 | if (ls->delta_stat >= sysctl_sched_stat_granularity) | |
832 | __update_curr_load(rq, ls); | |
833 | } | |
834 | ||
29b4b623 | 835 | static inline void inc_load(struct rq *rq, const struct task_struct *p) |
9c217245 | 836 | { |
84a1d7a2 | 837 | update_curr_load(rq); |
9c217245 IM |
838 | update_load_add(&rq->ls.load, p->se.load.weight); |
839 | } | |
840 | ||
79b5dddf | 841 | static inline void dec_load(struct rq *rq, const struct task_struct *p) |
9c217245 | 842 | { |
84a1d7a2 | 843 | update_curr_load(rq); |
9c217245 IM |
844 | update_load_sub(&rq->ls.load, p->se.load.weight); |
845 | } | |
846 | ||
e5fa2237 | 847 | static void inc_nr_running(struct task_struct *p, struct rq *rq) |
9c217245 IM |
848 | { |
849 | rq->nr_running++; | |
29b4b623 | 850 | inc_load(rq, p); |
9c217245 IM |
851 | } |
852 | ||
db53181e | 853 | static void dec_nr_running(struct task_struct *p, struct rq *rq) |
9c217245 IM |
854 | { |
855 | rq->nr_running--; | |
79b5dddf | 856 | dec_load(rq, p); |
9c217245 IM |
857 | } |
858 | ||
45bf76df IM |
859 | static void set_load_weight(struct task_struct *p) |
860 | { | |
dd41f596 IM |
861 | task_rq(p)->cfs.wait_runtime -= p->se.wait_runtime; |
862 | p->se.wait_runtime = 0; | |
863 | ||
45bf76df | 864 | if (task_has_rt_policy(p)) { |
dd41f596 IM |
865 | p->se.load.weight = prio_to_weight[0] * 2; |
866 | p->se.load.inv_weight = prio_to_wmult[0] >> 1; | |
867 | return; | |
868 | } | |
45bf76df | 869 | |
dd41f596 IM |
870 | /* |
871 | * SCHED_IDLE tasks get minimal weight: | |
872 | */ | |
873 | if (p->policy == SCHED_IDLE) { | |
874 | p->se.load.weight = WEIGHT_IDLEPRIO; | |
875 | p->se.load.inv_weight = WMULT_IDLEPRIO; | |
876 | return; | |
877 | } | |
71f8bd46 | 878 | |
dd41f596 IM |
879 | p->se.load.weight = prio_to_weight[p->static_prio - MAX_RT_PRIO]; |
880 | p->se.load.inv_weight = prio_to_wmult[p->static_prio - MAX_RT_PRIO]; | |
71f8bd46 IM |
881 | } |
882 | ||
8159f87e | 883 | static void enqueue_task(struct rq *rq, struct task_struct *p, int wakeup) |
71f8bd46 | 884 | { |
dd41f596 | 885 | sched_info_queued(p); |
fd390f6a | 886 | p->sched_class->enqueue_task(rq, p, wakeup); |
dd41f596 | 887 | p->se.on_rq = 1; |
71f8bd46 IM |
888 | } |
889 | ||
69be72c1 | 890 | static void dequeue_task(struct rq *rq, struct task_struct *p, int sleep) |
71f8bd46 | 891 | { |
f02231e5 | 892 | p->sched_class->dequeue_task(rq, p, sleep); |
dd41f596 | 893 | p->se.on_rq = 0; |
71f8bd46 IM |
894 | } |
895 | ||
14531189 | 896 | /* |
dd41f596 | 897 | * __normal_prio - return the priority that is based on the static prio |
14531189 | 898 | */ |
14531189 IM |
899 | static inline int __normal_prio(struct task_struct *p) |
900 | { | |
dd41f596 | 901 | return p->static_prio; |
14531189 IM |
902 | } |
903 | ||
b29739f9 IM |
904 | /* |
905 | * Calculate the expected normal priority: i.e. priority | |
906 | * without taking RT-inheritance into account. Might be | |
907 | * boosted by interactivity modifiers. Changes upon fork, | |
908 | * setprio syscalls, and whenever the interactivity | |
909 | * estimator recalculates. | |
910 | */ | |
36c8b586 | 911 | static inline int normal_prio(struct task_struct *p) |
b29739f9 IM |
912 | { |
913 | int prio; | |
914 | ||
e05606d3 | 915 | if (task_has_rt_policy(p)) |
b29739f9 IM |
916 | prio = MAX_RT_PRIO-1 - p->rt_priority; |
917 | else | |
918 | prio = __normal_prio(p); | |
919 | return prio; | |
920 | } | |
921 | ||
922 | /* | |
923 | * Calculate the current priority, i.e. the priority | |
924 | * taken into account by the scheduler. This value might | |
925 | * be boosted by RT tasks, or might be boosted by | |
926 | * interactivity modifiers. Will be RT if the task got | |
927 | * RT-boosted. If not then it returns p->normal_prio. | |
928 | */ | |
36c8b586 | 929 | static int effective_prio(struct task_struct *p) |
b29739f9 IM |
930 | { |
931 | p->normal_prio = normal_prio(p); | |
932 | /* | |
933 | * If we are RT tasks or we were boosted to RT priority, | |
934 | * keep the priority unchanged. Otherwise, update priority | |
935 | * to the normal priority: | |
936 | */ | |
937 | if (!rt_prio(p->prio)) | |
938 | return p->normal_prio; | |
939 | return p->prio; | |
940 | } | |
941 | ||
1da177e4 | 942 | /* |
dd41f596 | 943 | * activate_task - move a task to the runqueue. |
1da177e4 | 944 | */ |
dd41f596 | 945 | static void activate_task(struct rq *rq, struct task_struct *p, int wakeup) |
1da177e4 | 946 | { |
dd41f596 IM |
947 | if (p->state == TASK_UNINTERRUPTIBLE) |
948 | rq->nr_uninterruptible--; | |
1da177e4 | 949 | |
8159f87e | 950 | enqueue_task(rq, p, wakeup); |
e5fa2237 | 951 | inc_nr_running(p, rq); |
1da177e4 LT |
952 | } |
953 | ||
954 | /* | |
dd41f596 | 955 | * activate_idle_task - move idle task to the _front_ of runqueue. |
1da177e4 | 956 | */ |
dd41f596 | 957 | static inline void activate_idle_task(struct task_struct *p, struct rq *rq) |
1da177e4 | 958 | { |
a8e504d2 | 959 | update_rq_clock(rq); |
1da177e4 | 960 | |
dd41f596 IM |
961 | if (p->state == TASK_UNINTERRUPTIBLE) |
962 | rq->nr_uninterruptible--; | |
ece8a684 | 963 | |
8159f87e | 964 | enqueue_task(rq, p, 0); |
e5fa2237 | 965 | inc_nr_running(p, rq); |
1da177e4 LT |
966 | } |
967 | ||
968 | /* | |
969 | * deactivate_task - remove a task from the runqueue. | |
970 | */ | |
2e1cb74a | 971 | static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep) |
1da177e4 | 972 | { |
dd41f596 IM |
973 | if (p->state == TASK_UNINTERRUPTIBLE) |
974 | rq->nr_uninterruptible++; | |
975 | ||
69be72c1 | 976 | dequeue_task(rq, p, sleep); |
db53181e | 977 | dec_nr_running(p, rq); |
1da177e4 LT |
978 | } |
979 | ||
1da177e4 LT |
980 | /** |
981 | * task_curr - is this task currently executing on a CPU? | |
982 | * @p: the task in question. | |
983 | */ | |
36c8b586 | 984 | inline int task_curr(const struct task_struct *p) |
1da177e4 LT |
985 | { |
986 | return cpu_curr(task_cpu(p)) == p; | |
987 | } | |
988 | ||
2dd73a4f PW |
989 | /* Used instead of source_load when we know the type == 0 */ |
990 | unsigned long weighted_cpuload(const int cpu) | |
991 | { | |
dd41f596 IM |
992 | return cpu_rq(cpu)->ls.load.weight; |
993 | } | |
994 | ||
995 | static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu) | |
996 | { | |
997 | #ifdef CONFIG_SMP | |
998 | task_thread_info(p)->cpu = cpu; | |
999 | set_task_cfs_rq(p); | |
1000 | #endif | |
2dd73a4f PW |
1001 | } |
1002 | ||
1da177e4 | 1003 | #ifdef CONFIG_SMP |
c65cc870 | 1004 | |
dd41f596 | 1005 | void set_task_cpu(struct task_struct *p, unsigned int new_cpu) |
c65cc870 | 1006 | { |
dd41f596 IM |
1007 | int old_cpu = task_cpu(p); |
1008 | struct rq *old_rq = cpu_rq(old_cpu), *new_rq = cpu_rq(new_cpu); | |
1009 | u64 clock_offset, fair_clock_offset; | |
1010 | ||
1011 | clock_offset = old_rq->clock - new_rq->clock; | |
6cfb0d5d IM |
1012 | fair_clock_offset = old_rq->cfs.fair_clock - new_rq->cfs.fair_clock; |
1013 | ||
dd41f596 IM |
1014 | if (p->se.wait_start_fair) |
1015 | p->se.wait_start_fair -= fair_clock_offset; | |
6cfb0d5d IM |
1016 | if (p->se.sleep_start_fair) |
1017 | p->se.sleep_start_fair -= fair_clock_offset; | |
1018 | ||
1019 | #ifdef CONFIG_SCHEDSTATS | |
1020 | if (p->se.wait_start) | |
1021 | p->se.wait_start -= clock_offset; | |
dd41f596 IM |
1022 | if (p->se.sleep_start) |
1023 | p->se.sleep_start -= clock_offset; | |
1024 | if (p->se.block_start) | |
1025 | p->se.block_start -= clock_offset; | |
6cfb0d5d | 1026 | #endif |
dd41f596 IM |
1027 | |
1028 | __set_task_cpu(p, new_cpu); | |
c65cc870 IM |
1029 | } |
1030 | ||
70b97a7f | 1031 | struct migration_req { |
1da177e4 | 1032 | struct list_head list; |
1da177e4 | 1033 | |
36c8b586 | 1034 | struct task_struct *task; |
1da177e4 LT |
1035 | int dest_cpu; |
1036 | ||
1da177e4 | 1037 | struct completion done; |
70b97a7f | 1038 | }; |
1da177e4 LT |
1039 | |
1040 | /* | |
1041 | * The task's runqueue lock must be held. | |
1042 | * Returns true if you have to wait for migration thread. | |
1043 | */ | |
36c8b586 | 1044 | static int |
70b97a7f | 1045 | migrate_task(struct task_struct *p, int dest_cpu, struct migration_req *req) |
1da177e4 | 1046 | { |
70b97a7f | 1047 | struct rq *rq = task_rq(p); |
1da177e4 LT |
1048 | |
1049 | /* | |
1050 | * If the task is not on a runqueue (and not running), then | |
1051 | * it is sufficient to simply update the task's cpu field. | |
1052 | */ | |
dd41f596 | 1053 | if (!p->se.on_rq && !task_running(rq, p)) { |
1da177e4 LT |
1054 | set_task_cpu(p, dest_cpu); |
1055 | return 0; | |
1056 | } | |
1057 | ||
1058 | init_completion(&req->done); | |
1da177e4 LT |
1059 | req->task = p; |
1060 | req->dest_cpu = dest_cpu; | |
1061 | list_add(&req->list, &rq->migration_queue); | |
48f24c4d | 1062 | |
1da177e4 LT |
1063 | return 1; |
1064 | } | |
1065 | ||
1066 | /* | |
1067 | * wait_task_inactive - wait for a thread to unschedule. | |
1068 | * | |
1069 | * The caller must ensure that the task *will* unschedule sometime soon, | |
1070 | * else this function might spin for a *long* time. This function can't | |
1071 | * be called with interrupts off, or it may introduce deadlock with | |
1072 | * smp_call_function() if an IPI is sent by the same process we are | |
1073 | * waiting to become inactive. | |
1074 | */ | |
36c8b586 | 1075 | void wait_task_inactive(struct task_struct *p) |
1da177e4 LT |
1076 | { |
1077 | unsigned long flags; | |
dd41f596 | 1078 | int running, on_rq; |
70b97a7f | 1079 | struct rq *rq; |
1da177e4 LT |
1080 | |
1081 | repeat: | |
fa490cfd LT |
1082 | /* |
1083 | * We do the initial early heuristics without holding | |
1084 | * any task-queue locks at all. We'll only try to get | |
1085 | * the runqueue lock when things look like they will | |
1086 | * work out! | |
1087 | */ | |
1088 | rq = task_rq(p); | |
1089 | ||
1090 | /* | |
1091 | * If the task is actively running on another CPU | |
1092 | * still, just relax and busy-wait without holding | |
1093 | * any locks. | |
1094 | * | |
1095 | * NOTE! Since we don't hold any locks, it's not | |
1096 | * even sure that "rq" stays as the right runqueue! | |
1097 | * But we don't care, since "task_running()" will | |
1098 | * return false if the runqueue has changed and p | |
1099 | * is actually now running somewhere else! | |
1100 | */ | |
1101 | while (task_running(rq, p)) | |
1102 | cpu_relax(); | |
1103 | ||
1104 | /* | |
1105 | * Ok, time to look more closely! We need the rq | |
1106 | * lock now, to be *sure*. If we're wrong, we'll | |
1107 | * just go back and repeat. | |
1108 | */ | |
1da177e4 | 1109 | rq = task_rq_lock(p, &flags); |
fa490cfd | 1110 | running = task_running(rq, p); |
dd41f596 | 1111 | on_rq = p->se.on_rq; |
fa490cfd LT |
1112 | task_rq_unlock(rq, &flags); |
1113 | ||
1114 | /* | |
1115 | * Was it really running after all now that we | |
1116 | * checked with the proper locks actually held? | |
1117 | * | |
1118 | * Oops. Go back and try again.. | |
1119 | */ | |
1120 | if (unlikely(running)) { | |
1da177e4 | 1121 | cpu_relax(); |
1da177e4 LT |
1122 | goto repeat; |
1123 | } | |
fa490cfd LT |
1124 | |
1125 | /* | |
1126 | * It's not enough that it's not actively running, | |
1127 | * it must be off the runqueue _entirely_, and not | |
1128 | * preempted! | |
1129 | * | |
1130 | * So if it wa still runnable (but just not actively | |
1131 | * running right now), it's preempted, and we should | |
1132 | * yield - it could be a while. | |
1133 | */ | |
dd41f596 | 1134 | if (unlikely(on_rq)) { |
fa490cfd LT |
1135 | yield(); |
1136 | goto repeat; | |
1137 | } | |
1138 | ||
1139 | /* | |
1140 | * Ahh, all good. It wasn't running, and it wasn't | |
1141 | * runnable, which means that it will never become | |
1142 | * running in the future either. We're all done! | |
1143 | */ | |
1da177e4 LT |
1144 | } |
1145 | ||
1146 | /*** | |
1147 | * kick_process - kick a running thread to enter/exit the kernel | |
1148 | * @p: the to-be-kicked thread | |
1149 | * | |
1150 | * Cause a process which is running on another CPU to enter | |
1151 | * kernel-mode, without any delay. (to get signals handled.) | |
1152 | * | |
1153 | * NOTE: this function doesnt have to take the runqueue lock, | |
1154 | * because all it wants to ensure is that the remote task enters | |
1155 | * the kernel. If the IPI races and the task has been migrated | |
1156 | * to another CPU then no harm is done and the purpose has been | |
1157 | * achieved as well. | |
1158 | */ | |
36c8b586 | 1159 | void kick_process(struct task_struct *p) |
1da177e4 LT |
1160 | { |
1161 | int cpu; | |
1162 | ||
1163 | preempt_disable(); | |
1164 | cpu = task_cpu(p); | |
1165 | if ((cpu != smp_processor_id()) && task_curr(p)) | |
1166 | smp_send_reschedule(cpu); | |
1167 | preempt_enable(); | |
1168 | } | |
1169 | ||
1170 | /* | |
2dd73a4f PW |
1171 | * Return a low guess at the load of a migration-source cpu weighted |
1172 | * according to the scheduling class and "nice" value. | |
1da177e4 LT |
1173 | * |
1174 | * We want to under-estimate the load of migration sources, to | |
1175 | * balance conservatively. | |
1176 | */ | |
a2000572 | 1177 | static inline unsigned long source_load(int cpu, int type) |
1da177e4 | 1178 | { |
70b97a7f | 1179 | struct rq *rq = cpu_rq(cpu); |
dd41f596 | 1180 | unsigned long total = weighted_cpuload(cpu); |
2dd73a4f | 1181 | |
3b0bd9bc | 1182 | if (type == 0) |
dd41f596 | 1183 | return total; |
b910472d | 1184 | |
dd41f596 | 1185 | return min(rq->cpu_load[type-1], total); |
1da177e4 LT |
1186 | } |
1187 | ||
1188 | /* | |
2dd73a4f PW |
1189 | * Return a high guess at the load of a migration-target cpu weighted |
1190 | * according to the scheduling class and "nice" value. | |
1da177e4 | 1191 | */ |
a2000572 | 1192 | static inline unsigned long target_load(int cpu, int type) |
1da177e4 | 1193 | { |
70b97a7f | 1194 | struct rq *rq = cpu_rq(cpu); |
dd41f596 | 1195 | unsigned long total = weighted_cpuload(cpu); |
2dd73a4f | 1196 | |
7897986b | 1197 | if (type == 0) |
dd41f596 | 1198 | return total; |
3b0bd9bc | 1199 | |
dd41f596 | 1200 | return max(rq->cpu_load[type-1], total); |
2dd73a4f PW |
1201 | } |
1202 | ||
1203 | /* | |
1204 | * Return the average load per task on the cpu's run queue | |
1205 | */ | |
1206 | static inline unsigned long cpu_avg_load_per_task(int cpu) | |
1207 | { | |
70b97a7f | 1208 | struct rq *rq = cpu_rq(cpu); |
dd41f596 | 1209 | unsigned long total = weighted_cpuload(cpu); |
2dd73a4f PW |
1210 | unsigned long n = rq->nr_running; |
1211 | ||
dd41f596 | 1212 | return n ? total / n : SCHED_LOAD_SCALE; |
1da177e4 LT |
1213 | } |
1214 | ||
147cbb4b NP |
1215 | /* |
1216 | * find_idlest_group finds and returns the least busy CPU group within the | |
1217 | * domain. | |
1218 | */ | |
1219 | static struct sched_group * | |
1220 | find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu) | |
1221 | { | |
1222 | struct sched_group *idlest = NULL, *this = NULL, *group = sd->groups; | |
1223 | unsigned long min_load = ULONG_MAX, this_load = 0; | |
1224 | int load_idx = sd->forkexec_idx; | |
1225 | int imbalance = 100 + (sd->imbalance_pct-100)/2; | |
1226 | ||
1227 | do { | |
1228 | unsigned long load, avg_load; | |
1229 | int local_group; | |
1230 | int i; | |
1231 | ||
da5a5522 BD |
1232 | /* Skip over this group if it has no CPUs allowed */ |
1233 | if (!cpus_intersects(group->cpumask, p->cpus_allowed)) | |
1234 | goto nextgroup; | |
1235 | ||
147cbb4b | 1236 | local_group = cpu_isset(this_cpu, group->cpumask); |
147cbb4b NP |
1237 | |
1238 | /* Tally up the load of all CPUs in the group */ | |
1239 | avg_load = 0; | |
1240 | ||
1241 | for_each_cpu_mask(i, group->cpumask) { | |
1242 | /* Bias balancing toward cpus of our domain */ | |
1243 | if (local_group) | |
1244 | load = source_load(i, load_idx); | |
1245 | else | |
1246 | load = target_load(i, load_idx); | |
1247 | ||
1248 | avg_load += load; | |
1249 | } | |
1250 | ||
1251 | /* Adjust by relative CPU power of the group */ | |
5517d86b ED |
1252 | avg_load = sg_div_cpu_power(group, |
1253 | avg_load * SCHED_LOAD_SCALE); | |
147cbb4b NP |
1254 | |
1255 | if (local_group) { | |
1256 | this_load = avg_load; | |
1257 | this = group; | |
1258 | } else if (avg_load < min_load) { | |
1259 | min_load = avg_load; | |
1260 | idlest = group; | |
1261 | } | |
da5a5522 | 1262 | nextgroup: |
147cbb4b NP |
1263 | group = group->next; |
1264 | } while (group != sd->groups); | |
1265 | ||
1266 | if (!idlest || 100*this_load < imbalance*min_load) | |
1267 | return NULL; | |
1268 | return idlest; | |
1269 | } | |
1270 | ||
1271 | /* | |
0feaece9 | 1272 | * find_idlest_cpu - find the idlest cpu among the cpus in group. |
147cbb4b | 1273 | */ |
95cdf3b7 IM |
1274 | static int |
1275 | find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu) | |
147cbb4b | 1276 | { |
da5a5522 | 1277 | cpumask_t tmp; |
147cbb4b NP |
1278 | unsigned long load, min_load = ULONG_MAX; |
1279 | int idlest = -1; | |
1280 | int i; | |
1281 | ||
da5a5522 BD |
1282 | /* Traverse only the allowed CPUs */ |
1283 | cpus_and(tmp, group->cpumask, p->cpus_allowed); | |
1284 | ||
1285 | for_each_cpu_mask(i, tmp) { | |
2dd73a4f | 1286 | load = weighted_cpuload(i); |
147cbb4b NP |
1287 | |
1288 | if (load < min_load || (load == min_load && i == this_cpu)) { | |
1289 | min_load = load; | |
1290 | idlest = i; | |
1291 | } | |
1292 | } | |
1293 | ||
1294 | return idlest; | |
1295 | } | |
1296 | ||
476d139c NP |
1297 | /* |
1298 | * sched_balance_self: balance the current task (running on cpu) in domains | |
1299 | * that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and | |
1300 | * SD_BALANCE_EXEC. | |
1301 | * | |
1302 | * Balance, ie. select the least loaded group. | |
1303 | * | |
1304 | * Returns the target CPU number, or the same CPU if no balancing is needed. | |
1305 | * | |
1306 | * preempt must be disabled. | |
1307 | */ | |
1308 | static int sched_balance_self(int cpu, int flag) | |
1309 | { | |
1310 | struct task_struct *t = current; | |
1311 | struct sched_domain *tmp, *sd = NULL; | |
147cbb4b | 1312 | |
c96d145e | 1313 | for_each_domain(cpu, tmp) { |
9761eea8 IM |
1314 | /* |
1315 | * If power savings logic is enabled for a domain, stop there. | |
1316 | */ | |
5c45bf27 SS |
1317 | if (tmp->flags & SD_POWERSAVINGS_BALANCE) |
1318 | break; | |
476d139c NP |
1319 | if (tmp->flags & flag) |
1320 | sd = tmp; | |
c96d145e | 1321 | } |
476d139c NP |
1322 | |
1323 | while (sd) { | |
1324 | cpumask_t span; | |
1325 | struct sched_group *group; | |
1a848870 SS |
1326 | int new_cpu, weight; |
1327 | ||
1328 | if (!(sd->flags & flag)) { | |
1329 | sd = sd->child; | |
1330 | continue; | |
1331 | } | |
476d139c NP |
1332 | |
1333 | span = sd->span; | |
1334 | group = find_idlest_group(sd, t, cpu); | |
1a848870 SS |
1335 | if (!group) { |
1336 | sd = sd->child; | |
1337 | continue; | |
1338 | } | |
476d139c | 1339 | |
da5a5522 | 1340 | new_cpu = find_idlest_cpu(group, t, cpu); |
1a848870 SS |
1341 | if (new_cpu == -1 || new_cpu == cpu) { |
1342 | /* Now try balancing at a lower domain level of cpu */ | |
1343 | sd = sd->child; | |
1344 | continue; | |
1345 | } | |
476d139c | 1346 | |
1a848870 | 1347 | /* Now try balancing at a lower domain level of new_cpu */ |
476d139c | 1348 | cpu = new_cpu; |
476d139c NP |
1349 | sd = NULL; |
1350 | weight = cpus_weight(span); | |
1351 | for_each_domain(cpu, tmp) { | |
1352 | if (weight <= cpus_weight(tmp->span)) | |
1353 | break; | |
1354 | if (tmp->flags & flag) | |
1355 | sd = tmp; | |
1356 | } | |
1357 | /* while loop will break here if sd == NULL */ | |
1358 | } | |
1359 | ||
1360 | return cpu; | |
1361 | } | |
1362 | ||
1363 | #endif /* CONFIG_SMP */ | |
1da177e4 LT |
1364 | |
1365 | /* | |
1366 | * wake_idle() will wake a task on an idle cpu if task->cpu is | |
1367 | * not idle and an idle cpu is available. The span of cpus to | |
1368 | * search starts with cpus closest then further out as needed, | |
1369 | * so we always favor a closer, idle cpu. | |
1370 | * | |
1371 | * Returns the CPU we should wake onto. | |
1372 | */ | |
1373 | #if defined(ARCH_HAS_SCHED_WAKE_IDLE) | |
36c8b586 | 1374 | static int wake_idle(int cpu, struct task_struct *p) |
1da177e4 LT |
1375 | { |
1376 | cpumask_t tmp; | |
1377 | struct sched_domain *sd; | |
1378 | int i; | |
1379 | ||
4953198b SS |
1380 | /* |
1381 | * If it is idle, then it is the best cpu to run this task. | |
1382 | * | |
1383 | * This cpu is also the best, if it has more than one task already. | |
1384 | * Siblings must be also busy(in most cases) as they didn't already | |
1385 | * pickup the extra load from this cpu and hence we need not check | |
1386 | * sibling runqueue info. This will avoid the checks and cache miss | |
1387 | * penalities associated with that. | |
1388 | */ | |
1389 | if (idle_cpu(cpu) || cpu_rq(cpu)->nr_running > 1) | |
1da177e4 LT |
1390 | return cpu; |
1391 | ||
1392 | for_each_domain(cpu, sd) { | |
1393 | if (sd->flags & SD_WAKE_IDLE) { | |
e0f364f4 | 1394 | cpus_and(tmp, sd->span, p->cpus_allowed); |
1da177e4 LT |
1395 | for_each_cpu_mask(i, tmp) { |
1396 | if (idle_cpu(i)) | |
1397 | return i; | |
1398 | } | |
9761eea8 | 1399 | } else { |
e0f364f4 | 1400 | break; |
9761eea8 | 1401 | } |
1da177e4 LT |
1402 | } |
1403 | return cpu; | |
1404 | } | |
1405 | #else | |
36c8b586 | 1406 | static inline int wake_idle(int cpu, struct task_struct *p) |
1da177e4 LT |
1407 | { |
1408 | return cpu; | |
1409 | } | |
1410 | #endif | |
1411 | ||
1412 | /*** | |
1413 | * try_to_wake_up - wake up a thread | |
1414 | * @p: the to-be-woken-up thread | |
1415 | * @state: the mask of task states that can be woken | |
1416 | * @sync: do a synchronous wakeup? | |
1417 | * | |
1418 | * Put it on the run-queue if it's not already there. The "current" | |
1419 | * thread is always on the run-queue (except when the actual | |
1420 | * re-schedule is in progress), and as such you're allowed to do | |
1421 | * the simpler "current->state = TASK_RUNNING" to mark yourself | |
1422 | * runnable without the overhead of this. | |
1423 | * | |
1424 | * returns failure only if the task is already active. | |
1425 | */ | |
36c8b586 | 1426 | static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync) |
1da177e4 LT |
1427 | { |
1428 | int cpu, this_cpu, success = 0; | |
1429 | unsigned long flags; | |
1430 | long old_state; | |
70b97a7f | 1431 | struct rq *rq; |
1da177e4 | 1432 | #ifdef CONFIG_SMP |
7897986b | 1433 | struct sched_domain *sd, *this_sd = NULL; |
70b97a7f | 1434 | unsigned long load, this_load; |
1da177e4 LT |
1435 | int new_cpu; |
1436 | #endif | |
1437 | ||
1438 | rq = task_rq_lock(p, &flags); | |
1439 | old_state = p->state; | |
1440 | if (!(old_state & state)) | |
1441 | goto out; | |
1442 | ||
dd41f596 | 1443 | if (p->se.on_rq) |
1da177e4 LT |
1444 | goto out_running; |
1445 | ||
1446 | cpu = task_cpu(p); | |
1447 | this_cpu = smp_processor_id(); | |
1448 | ||
1449 | #ifdef CONFIG_SMP | |
1450 | if (unlikely(task_running(rq, p))) | |
1451 | goto out_activate; | |
1452 | ||
7897986b NP |
1453 | new_cpu = cpu; |
1454 | ||
1da177e4 LT |
1455 | schedstat_inc(rq, ttwu_cnt); |
1456 | if (cpu == this_cpu) { | |
1457 | schedstat_inc(rq, ttwu_local); | |
7897986b NP |
1458 | goto out_set_cpu; |
1459 | } | |
1460 | ||
1461 | for_each_domain(this_cpu, sd) { | |
1462 | if (cpu_isset(cpu, sd->span)) { | |
1463 | schedstat_inc(sd, ttwu_wake_remote); | |
1464 | this_sd = sd; | |
1465 | break; | |
1da177e4 LT |
1466 | } |
1467 | } | |
1da177e4 | 1468 | |
7897986b | 1469 | if (unlikely(!cpu_isset(this_cpu, p->cpus_allowed))) |
1da177e4 LT |
1470 | goto out_set_cpu; |
1471 | ||
1da177e4 | 1472 | /* |
7897986b | 1473 | * Check for affine wakeup and passive balancing possibilities. |
1da177e4 | 1474 | */ |
7897986b NP |
1475 | if (this_sd) { |
1476 | int idx = this_sd->wake_idx; | |
1477 | unsigned int imbalance; | |
1da177e4 | 1478 | |
a3f21bce NP |
1479 | imbalance = 100 + (this_sd->imbalance_pct - 100) / 2; |
1480 | ||
7897986b NP |
1481 | load = source_load(cpu, idx); |
1482 | this_load = target_load(this_cpu, idx); | |
1da177e4 | 1483 | |
7897986b NP |
1484 | new_cpu = this_cpu; /* Wake to this CPU if we can */ |
1485 | ||
a3f21bce NP |
1486 | if (this_sd->flags & SD_WAKE_AFFINE) { |
1487 | unsigned long tl = this_load; | |
33859f7f MOS |
1488 | unsigned long tl_per_task; |
1489 | ||
1490 | tl_per_task = cpu_avg_load_per_task(this_cpu); | |
2dd73a4f | 1491 | |
1da177e4 | 1492 | /* |
a3f21bce NP |
1493 | * If sync wakeup then subtract the (maximum possible) |
1494 | * effect of the currently running task from the load | |
1495 | * of the current CPU: | |
1da177e4 | 1496 | */ |
a3f21bce | 1497 | if (sync) |
dd41f596 | 1498 | tl -= current->se.load.weight; |
a3f21bce NP |
1499 | |
1500 | if ((tl <= load && | |
2dd73a4f | 1501 | tl + target_load(cpu, idx) <= tl_per_task) || |
dd41f596 | 1502 | 100*(tl + p->se.load.weight) <= imbalance*load) { |
a3f21bce NP |
1503 | /* |
1504 | * This domain has SD_WAKE_AFFINE and | |
1505 | * p is cache cold in this domain, and | |
1506 | * there is no bad imbalance. | |
1507 | */ | |
1508 | schedstat_inc(this_sd, ttwu_move_affine); | |
1509 | goto out_set_cpu; | |
1510 | } | |
1511 | } | |
1512 | ||
1513 | /* | |
1514 | * Start passive balancing when half the imbalance_pct | |
1515 | * limit is reached. | |
1516 | */ | |
1517 | if (this_sd->flags & SD_WAKE_BALANCE) { | |
1518 | if (imbalance*this_load <= 100*load) { | |
1519 | schedstat_inc(this_sd, ttwu_move_balance); | |
1520 | goto out_set_cpu; | |
1521 | } | |
1da177e4 LT |
1522 | } |
1523 | } | |
1524 | ||
1525 | new_cpu = cpu; /* Could not wake to this_cpu. Wake to cpu instead */ | |
1526 | out_set_cpu: | |
1527 | new_cpu = wake_idle(new_cpu, p); | |
1528 | if (new_cpu != cpu) { | |
1529 | set_task_cpu(p, new_cpu); | |
1530 | task_rq_unlock(rq, &flags); | |
1531 | /* might preempt at this point */ | |
1532 | rq = task_rq_lock(p, &flags); | |
1533 | old_state = p->state; | |
1534 | if (!(old_state & state)) | |
1535 | goto out; | |
dd41f596 | 1536 | if (p->se.on_rq) |
1da177e4 LT |
1537 | goto out_running; |
1538 | ||
1539 | this_cpu = smp_processor_id(); | |
1540 | cpu = task_cpu(p); | |
1541 | } | |
1542 | ||
1543 | out_activate: | |
1544 | #endif /* CONFIG_SMP */ | |
2daa3577 | 1545 | update_rq_clock(rq); |
dd41f596 | 1546 | activate_task(rq, p, 1); |
1da177e4 LT |
1547 | /* |
1548 | * Sync wakeups (i.e. those types of wakeups where the waker | |
1549 | * has indicated that it will leave the CPU in short order) | |
1550 | * don't trigger a preemption, if the woken up task will run on | |
1551 | * this cpu. (in this case the 'I will reschedule' promise of | |
1552 | * the waker guarantees that the freshly woken up task is going | |
1553 | * to be considered on this CPU.) | |
1554 | */ | |
dd41f596 IM |
1555 | if (!sync || cpu != this_cpu) |
1556 | check_preempt_curr(rq, p); | |
1da177e4 LT |
1557 | success = 1; |
1558 | ||
1559 | out_running: | |
1560 | p->state = TASK_RUNNING; | |
1561 | out: | |
1562 | task_rq_unlock(rq, &flags); | |
1563 | ||
1564 | return success; | |
1565 | } | |
1566 | ||
36c8b586 | 1567 | int fastcall wake_up_process(struct task_struct *p) |
1da177e4 LT |
1568 | { |
1569 | return try_to_wake_up(p, TASK_STOPPED | TASK_TRACED | | |
1570 | TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE, 0); | |
1571 | } | |
1da177e4 LT |
1572 | EXPORT_SYMBOL(wake_up_process); |
1573 | ||
36c8b586 | 1574 | int fastcall wake_up_state(struct task_struct *p, unsigned int state) |
1da177e4 LT |
1575 | { |
1576 | return try_to_wake_up(p, state, 0); | |
1577 | } | |
1578 | ||
1da177e4 LT |
1579 | /* |
1580 | * Perform scheduler related setup for a newly forked process p. | |
1581 | * p is forked by current. | |
dd41f596 IM |
1582 | * |
1583 | * __sched_fork() is basic setup used by init_idle() too: | |
1584 | */ | |
1585 | static void __sched_fork(struct task_struct *p) | |
1586 | { | |
1587 | p->se.wait_start_fair = 0; | |
dd41f596 IM |
1588 | p->se.exec_start = 0; |
1589 | p->se.sum_exec_runtime = 0; | |
1590 | p->se.delta_exec = 0; | |
1591 | p->se.delta_fair_run = 0; | |
1592 | p->se.delta_fair_sleep = 0; | |
1593 | p->se.wait_runtime = 0; | |
6cfb0d5d IM |
1594 | p->se.sleep_start_fair = 0; |
1595 | ||
1596 | #ifdef CONFIG_SCHEDSTATS | |
1597 | p->se.wait_start = 0; | |
dd41f596 IM |
1598 | p->se.sum_wait_runtime = 0; |
1599 | p->se.sum_sleep_runtime = 0; | |
1600 | p->se.sleep_start = 0; | |
dd41f596 IM |
1601 | p->se.block_start = 0; |
1602 | p->se.sleep_max = 0; | |
1603 | p->se.block_max = 0; | |
1604 | p->se.exec_max = 0; | |
1605 | p->se.wait_max = 0; | |
1606 | p->se.wait_runtime_overruns = 0; | |
1607 | p->se.wait_runtime_underruns = 0; | |
6cfb0d5d | 1608 | #endif |
476d139c | 1609 | |
dd41f596 IM |
1610 | INIT_LIST_HEAD(&p->run_list); |
1611 | p->se.on_rq = 0; | |
476d139c | 1612 | |
e107be36 AK |
1613 | #ifdef CONFIG_PREEMPT_NOTIFIERS |
1614 | INIT_HLIST_HEAD(&p->preempt_notifiers); | |
1615 | #endif | |
1616 | ||
1da177e4 LT |
1617 | /* |
1618 | * We mark the process as running here, but have not actually | |
1619 | * inserted it onto the runqueue yet. This guarantees that | |
1620 | * nobody will actually run it, and a signal or other external | |
1621 | * event cannot wake it up and insert it on the runqueue either. | |
1622 | */ | |
1623 | p->state = TASK_RUNNING; | |
dd41f596 IM |
1624 | } |
1625 | ||
1626 | /* | |
1627 | * fork()/clone()-time setup: | |
1628 | */ | |
1629 | void sched_fork(struct task_struct *p, int clone_flags) | |
1630 | { | |
1631 | int cpu = get_cpu(); | |
1632 | ||
1633 | __sched_fork(p); | |
1634 | ||
1635 | #ifdef CONFIG_SMP | |
1636 | cpu = sched_balance_self(cpu, SD_BALANCE_FORK); | |
1637 | #endif | |
1638 | __set_task_cpu(p, cpu); | |
b29739f9 IM |
1639 | |
1640 | /* | |
1641 | * Make sure we do not leak PI boosting priority to the child: | |
1642 | */ | |
1643 | p->prio = current->normal_prio; | |
1644 | ||
52f17b6c | 1645 | #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) |
dd41f596 | 1646 | if (likely(sched_info_on())) |
52f17b6c | 1647 | memset(&p->sched_info, 0, sizeof(p->sched_info)); |
1da177e4 | 1648 | #endif |
d6077cb8 | 1649 | #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW) |
4866cde0 NP |
1650 | p->oncpu = 0; |
1651 | #endif | |
1da177e4 | 1652 | #ifdef CONFIG_PREEMPT |
4866cde0 | 1653 | /* Want to start with kernel preemption disabled. */ |
a1261f54 | 1654 | task_thread_info(p)->preempt_count = 1; |
1da177e4 | 1655 | #endif |
476d139c | 1656 | put_cpu(); |
1da177e4 LT |
1657 | } |
1658 | ||
dd41f596 IM |
1659 | /* |
1660 | * After fork, child runs first. (default) If set to 0 then | |
1661 | * parent will (try to) run first. | |
1662 | */ | |
1663 | unsigned int __read_mostly sysctl_sched_child_runs_first = 1; | |
1664 | ||
1da177e4 LT |
1665 | /* |
1666 | * wake_up_new_task - wake up a newly created task for the first time. | |
1667 | * | |
1668 | * This function will do some initial scheduler statistics housekeeping | |
1669 | * that must be done for every newly created context, then puts the task | |
1670 | * on the runqueue and wakes it. | |
1671 | */ | |
36c8b586 | 1672 | void fastcall wake_up_new_task(struct task_struct *p, unsigned long clone_flags) |
1da177e4 LT |
1673 | { |
1674 | unsigned long flags; | |
dd41f596 IM |
1675 | struct rq *rq; |
1676 | int this_cpu; | |
1da177e4 LT |
1677 | |
1678 | rq = task_rq_lock(p, &flags); | |
147cbb4b | 1679 | BUG_ON(p->state != TASK_RUNNING); |
dd41f596 | 1680 | this_cpu = smp_processor_id(); /* parent's CPU */ |
a8e504d2 | 1681 | update_rq_clock(rq); |
1da177e4 LT |
1682 | |
1683 | p->prio = effective_prio(p); | |
1684 | ||
cad60d93 IM |
1685 | if (!p->sched_class->task_new || !sysctl_sched_child_runs_first || |
1686 | (clone_flags & CLONE_VM) || task_cpu(p) != this_cpu || | |
1687 | !current->se.on_rq) { | |
1688 | ||
dd41f596 | 1689 | activate_task(rq, p, 0); |
1da177e4 | 1690 | } else { |
1da177e4 | 1691 | /* |
dd41f596 IM |
1692 | * Let the scheduling class do new task startup |
1693 | * management (if any): | |
1da177e4 | 1694 | */ |
ee0827d8 | 1695 | p->sched_class->task_new(rq, p); |
e5fa2237 | 1696 | inc_nr_running(p, rq); |
1da177e4 | 1697 | } |
dd41f596 IM |
1698 | check_preempt_curr(rq, p); |
1699 | task_rq_unlock(rq, &flags); | |
1da177e4 LT |
1700 | } |
1701 | ||
e107be36 AK |
1702 | #ifdef CONFIG_PREEMPT_NOTIFIERS |
1703 | ||
1704 | /** | |
421cee29 RD |
1705 | * preempt_notifier_register - tell me when current is being being preempted & rescheduled |
1706 | * @notifier: notifier struct to register | |
e107be36 AK |
1707 | */ |
1708 | void preempt_notifier_register(struct preempt_notifier *notifier) | |
1709 | { | |
1710 | hlist_add_head(¬ifier->link, ¤t->preempt_notifiers); | |
1711 | } | |
1712 | EXPORT_SYMBOL_GPL(preempt_notifier_register); | |
1713 | ||
1714 | /** | |
1715 | * preempt_notifier_unregister - no longer interested in preemption notifications | |
421cee29 | 1716 | * @notifier: notifier struct to unregister |
e107be36 AK |
1717 | * |
1718 | * This is safe to call from within a preemption notifier. | |
1719 | */ | |
1720 | void preempt_notifier_unregister(struct preempt_notifier *notifier) | |
1721 | { | |
1722 | hlist_del(¬ifier->link); | |
1723 | } | |
1724 | EXPORT_SYMBOL_GPL(preempt_notifier_unregister); | |
1725 | ||
1726 | static void fire_sched_in_preempt_notifiers(struct task_struct *curr) | |
1727 | { | |
1728 | struct preempt_notifier *notifier; | |
1729 | struct hlist_node *node; | |
1730 | ||
1731 | hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link) | |
1732 | notifier->ops->sched_in(notifier, raw_smp_processor_id()); | |
1733 | } | |
1734 | ||
1735 | static void | |
1736 | fire_sched_out_preempt_notifiers(struct task_struct *curr, | |
1737 | struct task_struct *next) | |
1738 | { | |
1739 | struct preempt_notifier *notifier; | |
1740 | struct hlist_node *node; | |
1741 | ||
1742 | hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link) | |
1743 | notifier->ops->sched_out(notifier, next); | |
1744 | } | |
1745 | ||
1746 | #else | |
1747 | ||
1748 | static void fire_sched_in_preempt_notifiers(struct task_struct *curr) | |
1749 | { | |
1750 | } | |
1751 | ||
1752 | static void | |
1753 | fire_sched_out_preempt_notifiers(struct task_struct *curr, | |
1754 | struct task_struct *next) | |
1755 | { | |
1756 | } | |
1757 | ||
1758 | #endif | |
1759 | ||
4866cde0 NP |
1760 | /** |
1761 | * prepare_task_switch - prepare to switch tasks | |
1762 | * @rq: the runqueue preparing to switch | |
421cee29 | 1763 | * @prev: the current task that is being switched out |
4866cde0 NP |
1764 | * @next: the task we are going to switch to. |
1765 | * | |
1766 | * This is called with the rq lock held and interrupts off. It must | |
1767 | * be paired with a subsequent finish_task_switch after the context | |
1768 | * switch. | |
1769 | * | |
1770 | * prepare_task_switch sets up locking and calls architecture specific | |
1771 | * hooks. | |
1772 | */ | |
e107be36 AK |
1773 | static inline void |
1774 | prepare_task_switch(struct rq *rq, struct task_struct *prev, | |
1775 | struct task_struct *next) | |
4866cde0 | 1776 | { |
e107be36 | 1777 | fire_sched_out_preempt_notifiers(prev, next); |
4866cde0 NP |
1778 | prepare_lock_switch(rq, next); |
1779 | prepare_arch_switch(next); | |
1780 | } | |
1781 | ||
1da177e4 LT |
1782 | /** |
1783 | * finish_task_switch - clean up after a task-switch | |
344babaa | 1784 | * @rq: runqueue associated with task-switch |
1da177e4 LT |
1785 | * @prev: the thread we just switched away from. |
1786 | * | |
4866cde0 NP |
1787 | * finish_task_switch must be called after the context switch, paired |
1788 | * with a prepare_task_switch call before the context switch. | |
1789 | * finish_task_switch will reconcile locking set up by prepare_task_switch, | |
1790 | * and do any other architecture-specific cleanup actions. | |
1da177e4 LT |
1791 | * |
1792 | * Note that we may have delayed dropping an mm in context_switch(). If | |
1793 | * so, we finish that here outside of the runqueue lock. (Doing it | |
1794 | * with the lock held can cause deadlocks; see schedule() for | |
1795 | * details.) | |
1796 | */ | |
70b97a7f | 1797 | static inline void finish_task_switch(struct rq *rq, struct task_struct *prev) |
1da177e4 LT |
1798 | __releases(rq->lock) |
1799 | { | |
1da177e4 | 1800 | struct mm_struct *mm = rq->prev_mm; |
55a101f8 | 1801 | long prev_state; |
1da177e4 LT |
1802 | |
1803 | rq->prev_mm = NULL; | |
1804 | ||
1805 | /* | |
1806 | * A task struct has one reference for the use as "current". | |
c394cc9f | 1807 | * If a task dies, then it sets TASK_DEAD in tsk->state and calls |
55a101f8 ON |
1808 | * schedule one last time. The schedule call will never return, and |
1809 | * the scheduled task must drop that reference. | |
c394cc9f | 1810 | * The test for TASK_DEAD must occur while the runqueue locks are |
1da177e4 LT |
1811 | * still held, otherwise prev could be scheduled on another cpu, die |
1812 | * there before we look at prev->state, and then the reference would | |
1813 | * be dropped twice. | |
1814 | * Manfred Spraul <manfred@colorfullife.com> | |
1815 | */ | |
55a101f8 | 1816 | prev_state = prev->state; |
4866cde0 NP |
1817 | finish_arch_switch(prev); |
1818 | finish_lock_switch(rq, prev); | |
e107be36 | 1819 | fire_sched_in_preempt_notifiers(current); |
1da177e4 LT |
1820 | if (mm) |
1821 | mmdrop(mm); | |
c394cc9f | 1822 | if (unlikely(prev_state == TASK_DEAD)) { |
c6fd91f0 | 1823 | /* |
1824 | * Remove function-return probe instances associated with this | |
1825 | * task and put them back on the free list. | |
9761eea8 | 1826 | */ |
c6fd91f0 | 1827 | kprobe_flush_task(prev); |
1da177e4 | 1828 | put_task_struct(prev); |
c6fd91f0 | 1829 | } |
1da177e4 LT |
1830 | } |
1831 | ||
1832 | /** | |
1833 | * schedule_tail - first thing a freshly forked thread must call. | |
1834 | * @prev: the thread we just switched away from. | |
1835 | */ | |
36c8b586 | 1836 | asmlinkage void schedule_tail(struct task_struct *prev) |
1da177e4 LT |
1837 | __releases(rq->lock) |
1838 | { | |
70b97a7f IM |
1839 | struct rq *rq = this_rq(); |
1840 | ||
4866cde0 NP |
1841 | finish_task_switch(rq, prev); |
1842 | #ifdef __ARCH_WANT_UNLOCKED_CTXSW | |
1843 | /* In this case, finish_task_switch does not reenable preemption */ | |
1844 | preempt_enable(); | |
1845 | #endif | |
1da177e4 LT |
1846 | if (current->set_child_tid) |
1847 | put_user(current->pid, current->set_child_tid); | |
1848 | } | |
1849 | ||
1850 | /* | |
1851 | * context_switch - switch to the new MM and the new | |
1852 | * thread's register state. | |
1853 | */ | |
dd41f596 | 1854 | static inline void |
70b97a7f | 1855 | context_switch(struct rq *rq, struct task_struct *prev, |
36c8b586 | 1856 | struct task_struct *next) |
1da177e4 | 1857 | { |
dd41f596 | 1858 | struct mm_struct *mm, *oldmm; |
1da177e4 | 1859 | |
e107be36 | 1860 | prepare_task_switch(rq, prev, next); |
dd41f596 IM |
1861 | mm = next->mm; |
1862 | oldmm = prev->active_mm; | |
9226d125 ZA |
1863 | /* |
1864 | * For paravirt, this is coupled with an exit in switch_to to | |
1865 | * combine the page table reload and the switch backend into | |
1866 | * one hypercall. | |
1867 | */ | |
1868 | arch_enter_lazy_cpu_mode(); | |
1869 | ||
dd41f596 | 1870 | if (unlikely(!mm)) { |
1da177e4 LT |
1871 | next->active_mm = oldmm; |
1872 | atomic_inc(&oldmm->mm_count); | |
1873 | enter_lazy_tlb(oldmm, next); | |
1874 | } else | |
1875 | switch_mm(oldmm, mm, next); | |
1876 | ||
dd41f596 | 1877 | if (unlikely(!prev->mm)) { |
1da177e4 | 1878 | prev->active_mm = NULL; |
1da177e4 LT |
1879 | rq->prev_mm = oldmm; |
1880 | } | |
3a5f5e48 IM |
1881 | /* |
1882 | * Since the runqueue lock will be released by the next | |
1883 | * task (which is an invalid locking op but in the case | |
1884 | * of the scheduler it's an obvious special-case), so we | |
1885 | * do an early lockdep release here: | |
1886 | */ | |
1887 | #ifndef __ARCH_WANT_UNLOCKED_CTXSW | |
8a25d5de | 1888 | spin_release(&rq->lock.dep_map, 1, _THIS_IP_); |
3a5f5e48 | 1889 | #endif |
1da177e4 LT |
1890 | |
1891 | /* Here we just switch the register state and the stack. */ | |
1892 | switch_to(prev, next, prev); | |
1893 | ||
dd41f596 IM |
1894 | barrier(); |
1895 | /* | |
1896 | * this_rq must be evaluated again because prev may have moved | |
1897 | * CPUs since it called schedule(), thus the 'rq' on its stack | |
1898 | * frame will be invalid. | |
1899 | */ | |
1900 | finish_task_switch(this_rq(), prev); | |
1da177e4 LT |
1901 | } |
1902 | ||
1903 | /* | |
1904 | * nr_running, nr_uninterruptible and nr_context_switches: | |
1905 | * | |
1906 | * externally visible scheduler statistics: current number of runnable | |
1907 | * threads, current number of uninterruptible-sleeping threads, total | |
1908 | * number of context switches performed since bootup. | |
1909 | */ | |
1910 | unsigned long nr_running(void) | |
1911 | { | |
1912 | unsigned long i, sum = 0; | |
1913 | ||
1914 | for_each_online_cpu(i) | |
1915 | sum += cpu_rq(i)->nr_running; | |
1916 | ||
1917 | return sum; | |
1918 | } | |
1919 | ||
1920 | unsigned long nr_uninterruptible(void) | |
1921 | { | |
1922 | unsigned long i, sum = 0; | |
1923 | ||
0a945022 | 1924 | for_each_possible_cpu(i) |
1da177e4 LT |
1925 | sum += cpu_rq(i)->nr_uninterruptible; |
1926 | ||
1927 | /* | |
1928 | * Since we read the counters lockless, it might be slightly | |
1929 | * inaccurate. Do not allow it to go below zero though: | |
1930 | */ | |
1931 | if (unlikely((long)sum < 0)) | |
1932 | sum = 0; | |
1933 | ||
1934 | return sum; | |
1935 | } | |
1936 | ||
1937 | unsigned long long nr_context_switches(void) | |
1938 | { | |
cc94abfc SR |
1939 | int i; |
1940 | unsigned long long sum = 0; | |
1da177e4 | 1941 | |
0a945022 | 1942 | for_each_possible_cpu(i) |
1da177e4 LT |
1943 | sum += cpu_rq(i)->nr_switches; |
1944 | ||
1945 | return sum; | |
1946 | } | |
1947 | ||
1948 | unsigned long nr_iowait(void) | |
1949 | { | |
1950 | unsigned long i, sum = 0; | |
1951 | ||
0a945022 | 1952 | for_each_possible_cpu(i) |
1da177e4 LT |
1953 | sum += atomic_read(&cpu_rq(i)->nr_iowait); |
1954 | ||
1955 | return sum; | |
1956 | } | |
1957 | ||
db1b1fef JS |
1958 | unsigned long nr_active(void) |
1959 | { | |
1960 | unsigned long i, running = 0, uninterruptible = 0; | |
1961 | ||
1962 | for_each_online_cpu(i) { | |
1963 | running += cpu_rq(i)->nr_running; | |
1964 | uninterruptible += cpu_rq(i)->nr_uninterruptible; | |
1965 | } | |
1966 | ||
1967 | if (unlikely((long)uninterruptible < 0)) | |
1968 | uninterruptible = 0; | |
1969 | ||
1970 | return running + uninterruptible; | |
1971 | } | |
1972 | ||
48f24c4d | 1973 | /* |
dd41f596 IM |
1974 | * Update rq->cpu_load[] statistics. This function is usually called every |
1975 | * scheduler tick (TICK_NSEC). | |
48f24c4d | 1976 | */ |
dd41f596 | 1977 | static void update_cpu_load(struct rq *this_rq) |
48f24c4d | 1978 | { |
dd41f596 IM |
1979 | u64 fair_delta64, exec_delta64, idle_delta64, sample_interval64, tmp64; |
1980 | unsigned long total_load = this_rq->ls.load.weight; | |
1981 | unsigned long this_load = total_load; | |
1982 | struct load_stat *ls = &this_rq->ls; | |
dd41f596 IM |
1983 | int i, scale; |
1984 | ||
1985 | this_rq->nr_load_updates++; | |
1986 | if (unlikely(!(sysctl_sched_features & SCHED_FEAT_PRECISE_CPU_LOAD))) | |
1987 | goto do_avg; | |
1988 | ||
1989 | /* Update delta_fair/delta_exec fields first */ | |
84a1d7a2 | 1990 | update_curr_load(this_rq); |
dd41f596 IM |
1991 | |
1992 | fair_delta64 = ls->delta_fair + 1; | |
1993 | ls->delta_fair = 0; | |
1994 | ||
1995 | exec_delta64 = ls->delta_exec + 1; | |
1996 | ls->delta_exec = 0; | |
1997 | ||
d281918d IM |
1998 | sample_interval64 = this_rq->clock - ls->load_update_last; |
1999 | ls->load_update_last = this_rq->clock; | |
dd41f596 IM |
2000 | |
2001 | if ((s64)sample_interval64 < (s64)TICK_NSEC) | |
2002 | sample_interval64 = TICK_NSEC; | |
2003 | ||
2004 | if (exec_delta64 > sample_interval64) | |
2005 | exec_delta64 = sample_interval64; | |
2006 | ||
2007 | idle_delta64 = sample_interval64 - exec_delta64; | |
2008 | ||
2009 | tmp64 = div64_64(SCHED_LOAD_SCALE * exec_delta64, fair_delta64); | |
2010 | tmp64 = div64_64(tmp64 * exec_delta64, sample_interval64); | |
2011 | ||
2012 | this_load = (unsigned long)tmp64; | |
2013 | ||
2014 | do_avg: | |
2015 | ||
2016 | /* Update our load: */ | |
2017 | for (i = 0, scale = 1; i < CPU_LOAD_IDX_MAX; i++, scale += scale) { | |
2018 | unsigned long old_load, new_load; | |
2019 | ||
2020 | /* scale is effectively 1 << i now, and >> i divides by scale */ | |
2021 | ||
2022 | old_load = this_rq->cpu_load[i]; | |
2023 | new_load = this_load; | |
2024 | ||
2025 | this_rq->cpu_load[i] = (old_load*(scale-1) + new_load) >> i; | |
2026 | } | |
48f24c4d IM |
2027 | } |
2028 | ||
dd41f596 IM |
2029 | #ifdef CONFIG_SMP |
2030 | ||
1da177e4 LT |
2031 | /* |
2032 | * double_rq_lock - safely lock two runqueues | |
2033 | * | |
2034 | * Note this does not disable interrupts like task_rq_lock, | |
2035 | * you need to do so manually before calling. | |
2036 | */ | |
70b97a7f | 2037 | static void double_rq_lock(struct rq *rq1, struct rq *rq2) |
1da177e4 LT |
2038 | __acquires(rq1->lock) |
2039 | __acquires(rq2->lock) | |
2040 | { | |
054b9108 | 2041 | BUG_ON(!irqs_disabled()); |
1da177e4 LT |
2042 | if (rq1 == rq2) { |
2043 | spin_lock(&rq1->lock); | |
2044 | __acquire(rq2->lock); /* Fake it out ;) */ | |
2045 | } else { | |
c96d145e | 2046 | if (rq1 < rq2) { |
1da177e4 LT |
2047 | spin_lock(&rq1->lock); |
2048 | spin_lock(&rq2->lock); | |
2049 | } else { | |
2050 | spin_lock(&rq2->lock); | |
2051 | spin_lock(&rq1->lock); | |
2052 | } | |
2053 | } | |
6e82a3be IM |
2054 | update_rq_clock(rq1); |
2055 | update_rq_clock(rq2); | |
1da177e4 LT |
2056 | } |
2057 | ||
2058 | /* | |
2059 | * double_rq_unlock - safely unlock two runqueues | |
2060 | * | |
2061 | * Note this does not restore interrupts like task_rq_unlock, | |
2062 | * you need to do so manually after calling. | |
2063 | */ | |
70b97a7f | 2064 | static void double_rq_unlock(struct rq *rq1, struct rq *rq2) |
1da177e4 LT |
2065 | __releases(rq1->lock) |
2066 | __releases(rq2->lock) | |
2067 | { | |
2068 | spin_unlock(&rq1->lock); | |
2069 | if (rq1 != rq2) | |
2070 | spin_unlock(&rq2->lock); | |
2071 | else | |
2072 | __release(rq2->lock); | |
2073 | } | |
2074 | ||
2075 | /* | |
2076 | * double_lock_balance - lock the busiest runqueue, this_rq is locked already. | |
2077 | */ | |
70b97a7f | 2078 | static void double_lock_balance(struct rq *this_rq, struct rq *busiest) |
1da177e4 LT |
2079 | __releases(this_rq->lock) |
2080 | __acquires(busiest->lock) | |
2081 | __acquires(this_rq->lock) | |
2082 | { | |
054b9108 KK |
2083 | if (unlikely(!irqs_disabled())) { |
2084 | /* printk() doesn't work good under rq->lock */ | |
2085 | spin_unlock(&this_rq->lock); | |
2086 | BUG_ON(1); | |
2087 | } | |
1da177e4 | 2088 | if (unlikely(!spin_trylock(&busiest->lock))) { |
c96d145e | 2089 | if (busiest < this_rq) { |
1da177e4 LT |
2090 | spin_unlock(&this_rq->lock); |
2091 | spin_lock(&busiest->lock); | |
2092 | spin_lock(&this_rq->lock); | |
2093 | } else | |
2094 | spin_lock(&busiest->lock); | |
2095 | } | |
2096 | } | |
2097 | ||
1da177e4 LT |
2098 | /* |
2099 | * If dest_cpu is allowed for this process, migrate the task to it. | |
2100 | * This is accomplished by forcing the cpu_allowed mask to only | |
2101 | * allow dest_cpu, which will force the cpu onto dest_cpu. Then | |
2102 | * the cpu_allowed mask is restored. | |
2103 | */ | |
36c8b586 | 2104 | static void sched_migrate_task(struct task_struct *p, int dest_cpu) |
1da177e4 | 2105 | { |
70b97a7f | 2106 | struct migration_req req; |
1da177e4 | 2107 | unsigned long flags; |
70b97a7f | 2108 | struct rq *rq; |
1da177e4 LT |
2109 | |
2110 | rq = task_rq_lock(p, &flags); | |
2111 | if (!cpu_isset(dest_cpu, p->cpus_allowed) | |
2112 | || unlikely(cpu_is_offline(dest_cpu))) | |
2113 | goto out; | |
2114 | ||
2115 | /* force the process onto the specified CPU */ | |
2116 | if (migrate_task(p, dest_cpu, &req)) { | |
2117 | /* Need to wait for migration thread (might exit: take ref). */ | |
2118 | struct task_struct *mt = rq->migration_thread; | |
36c8b586 | 2119 | |
1da177e4 LT |
2120 | get_task_struct(mt); |
2121 | task_rq_unlock(rq, &flags); | |
2122 | wake_up_process(mt); | |
2123 | put_task_struct(mt); | |
2124 | wait_for_completion(&req.done); | |
36c8b586 | 2125 | |
1da177e4 LT |
2126 | return; |
2127 | } | |
2128 | out: | |
2129 | task_rq_unlock(rq, &flags); | |
2130 | } | |
2131 | ||
2132 | /* | |
476d139c NP |
2133 | * sched_exec - execve() is a valuable balancing opportunity, because at |
2134 | * this point the task has the smallest effective memory and cache footprint. | |
1da177e4 LT |
2135 | */ |
2136 | void sched_exec(void) | |
2137 | { | |
1da177e4 | 2138 | int new_cpu, this_cpu = get_cpu(); |
476d139c | 2139 | new_cpu = sched_balance_self(this_cpu, SD_BALANCE_EXEC); |
1da177e4 | 2140 | put_cpu(); |
476d139c NP |
2141 | if (new_cpu != this_cpu) |
2142 | sched_migrate_task(current, new_cpu); | |
1da177e4 LT |
2143 | } |
2144 | ||
2145 | /* | |
2146 | * pull_task - move a task from a remote runqueue to the local runqueue. | |
2147 | * Both runqueues must be locked. | |
2148 | */ | |
dd41f596 IM |
2149 | static void pull_task(struct rq *src_rq, struct task_struct *p, |
2150 | struct rq *this_rq, int this_cpu) | |
1da177e4 | 2151 | { |
2e1cb74a | 2152 | deactivate_task(src_rq, p, 0); |
1da177e4 | 2153 | set_task_cpu(p, this_cpu); |
dd41f596 | 2154 | activate_task(this_rq, p, 0); |
1da177e4 LT |
2155 | /* |
2156 | * Note that idle threads have a prio of MAX_PRIO, for this test | |
2157 | * to be always true for them. | |
2158 | */ | |
dd41f596 | 2159 | check_preempt_curr(this_rq, p); |
1da177e4 LT |
2160 | } |
2161 | ||
2162 | /* | |
2163 | * can_migrate_task - may task p from runqueue rq be migrated to this_cpu? | |
2164 | */ | |
858119e1 | 2165 | static |
70b97a7f | 2166 | int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu, |
d15bcfdb | 2167 | struct sched_domain *sd, enum cpu_idle_type idle, |
95cdf3b7 | 2168 | int *all_pinned) |
1da177e4 LT |
2169 | { |
2170 | /* | |
2171 | * We do not migrate tasks that are: | |
2172 | * 1) running (obviously), or | |
2173 | * 2) cannot be migrated to this CPU due to cpus_allowed, or | |
2174 | * 3) are cache-hot on their current CPU. | |
2175 | */ | |
1da177e4 LT |
2176 | if (!cpu_isset(this_cpu, p->cpus_allowed)) |
2177 | return 0; | |
81026794 NP |
2178 | *all_pinned = 0; |
2179 | ||
2180 | if (task_running(rq, p)) | |
2181 | return 0; | |
1da177e4 LT |
2182 | |
2183 | /* | |
dd41f596 | 2184 | * Aggressive migration if too many balance attempts have failed: |
1da177e4 | 2185 | */ |
dd41f596 | 2186 | if (sd->nr_balance_failed > sd->cache_nice_tries) |
1da177e4 LT |
2187 | return 1; |
2188 | ||
1da177e4 LT |
2189 | return 1; |
2190 | } | |
2191 | ||
dd41f596 | 2192 | static int balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, |
2dd73a4f | 2193 | unsigned long max_nr_move, unsigned long max_load_move, |
d15bcfdb | 2194 | struct sched_domain *sd, enum cpu_idle_type idle, |
dd41f596 | 2195 | int *all_pinned, unsigned long *load_moved, |
a4ac01c3 | 2196 | int *this_best_prio, struct rq_iterator *iterator) |
1da177e4 | 2197 | { |
dd41f596 IM |
2198 | int pulled = 0, pinned = 0, skip_for_load; |
2199 | struct task_struct *p; | |
2200 | long rem_load_move = max_load_move; | |
1da177e4 | 2201 | |
2dd73a4f | 2202 | if (max_nr_move == 0 || max_load_move == 0) |
1da177e4 LT |
2203 | goto out; |
2204 | ||
81026794 NP |
2205 | pinned = 1; |
2206 | ||
1da177e4 | 2207 | /* |
dd41f596 | 2208 | * Start the load-balancing iterator: |
1da177e4 | 2209 | */ |
dd41f596 IM |
2210 | p = iterator->start(iterator->arg); |
2211 | next: | |
2212 | if (!p) | |
1da177e4 | 2213 | goto out; |
50ddd969 PW |
2214 | /* |
2215 | * To help distribute high priority tasks accross CPUs we don't | |
2216 | * skip a task if it will be the highest priority task (i.e. smallest | |
2217 | * prio value) on its new queue regardless of its load weight | |
2218 | */ | |
dd41f596 IM |
2219 | skip_for_load = (p->se.load.weight >> 1) > rem_load_move + |
2220 | SCHED_LOAD_SCALE_FUZZ; | |
a4ac01c3 | 2221 | if ((skip_for_load && p->prio >= *this_best_prio) || |
dd41f596 | 2222 | !can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) { |
dd41f596 IM |
2223 | p = iterator->next(iterator->arg); |
2224 | goto next; | |
1da177e4 LT |
2225 | } |
2226 | ||
dd41f596 | 2227 | pull_task(busiest, p, this_rq, this_cpu); |
1da177e4 | 2228 | pulled++; |
dd41f596 | 2229 | rem_load_move -= p->se.load.weight; |
1da177e4 | 2230 | |
2dd73a4f PW |
2231 | /* |
2232 | * We only want to steal up to the prescribed number of tasks | |
2233 | * and the prescribed amount of weighted load. | |
2234 | */ | |
2235 | if (pulled < max_nr_move && rem_load_move > 0) { | |
a4ac01c3 PW |
2236 | if (p->prio < *this_best_prio) |
2237 | *this_best_prio = p->prio; | |
dd41f596 IM |
2238 | p = iterator->next(iterator->arg); |
2239 | goto next; | |
1da177e4 LT |
2240 | } |
2241 | out: | |
2242 | /* | |
2243 | * Right now, this is the only place pull_task() is called, | |
2244 | * so we can safely collect pull_task() stats here rather than | |
2245 | * inside pull_task(). | |
2246 | */ | |
2247 | schedstat_add(sd, lb_gained[idle], pulled); | |
81026794 NP |
2248 | |
2249 | if (all_pinned) | |
2250 | *all_pinned = pinned; | |
dd41f596 | 2251 | *load_moved = max_load_move - rem_load_move; |
1da177e4 LT |
2252 | return pulled; |
2253 | } | |
2254 | ||
dd41f596 | 2255 | /* |
43010659 PW |
2256 | * move_tasks tries to move up to max_load_move weighted load from busiest to |
2257 | * this_rq, as part of a balancing operation within domain "sd". | |
2258 | * Returns 1 if successful and 0 otherwise. | |
dd41f596 IM |
2259 | * |
2260 | * Called with both runqueues locked. | |
2261 | */ | |
2262 | static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
43010659 | 2263 | unsigned long max_load_move, |
dd41f596 IM |
2264 | struct sched_domain *sd, enum cpu_idle_type idle, |
2265 | int *all_pinned) | |
2266 | { | |
2267 | struct sched_class *class = sched_class_highest; | |
43010659 | 2268 | unsigned long total_load_moved = 0; |
a4ac01c3 | 2269 | int this_best_prio = this_rq->curr->prio; |
dd41f596 IM |
2270 | |
2271 | do { | |
43010659 PW |
2272 | total_load_moved += |
2273 | class->load_balance(this_rq, this_cpu, busiest, | |
2274 | ULONG_MAX, max_load_move - total_load_moved, | |
a4ac01c3 | 2275 | sd, idle, all_pinned, &this_best_prio); |
dd41f596 | 2276 | class = class->next; |
43010659 | 2277 | } while (class && max_load_move > total_load_moved); |
dd41f596 | 2278 | |
43010659 PW |
2279 | return total_load_moved > 0; |
2280 | } | |
2281 | ||
2282 | /* | |
2283 | * move_one_task tries to move exactly one task from busiest to this_rq, as | |
2284 | * part of active balancing operations within "domain". | |
2285 | * Returns 1 if successful and 0 otherwise. | |
2286 | * | |
2287 | * Called with both runqueues locked. | |
2288 | */ | |
2289 | static int move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
2290 | struct sched_domain *sd, enum cpu_idle_type idle) | |
2291 | { | |
2292 | struct sched_class *class; | |
a4ac01c3 | 2293 | int this_best_prio = MAX_PRIO; |
43010659 PW |
2294 | |
2295 | for (class = sched_class_highest; class; class = class->next) | |
2296 | if (class->load_balance(this_rq, this_cpu, busiest, | |
a4ac01c3 PW |
2297 | 1, ULONG_MAX, sd, idle, NULL, |
2298 | &this_best_prio)) | |
43010659 PW |
2299 | return 1; |
2300 | ||
2301 | return 0; | |
dd41f596 IM |
2302 | } |
2303 | ||
1da177e4 LT |
2304 | /* |
2305 | * find_busiest_group finds and returns the busiest CPU group within the | |
48f24c4d IM |
2306 | * domain. It calculates and returns the amount of weighted load which |
2307 | * should be moved to restore balance via the imbalance parameter. | |
1da177e4 LT |
2308 | */ |
2309 | static struct sched_group * | |
2310 | find_busiest_group(struct sched_domain *sd, int this_cpu, | |
dd41f596 IM |
2311 | unsigned long *imbalance, enum cpu_idle_type idle, |
2312 | int *sd_idle, cpumask_t *cpus, int *balance) | |
1da177e4 LT |
2313 | { |
2314 | struct sched_group *busiest = NULL, *this = NULL, *group = sd->groups; | |
2315 | unsigned long max_load, avg_load, total_load, this_load, total_pwr; | |
0c117f1b | 2316 | unsigned long max_pull; |
2dd73a4f PW |
2317 | unsigned long busiest_load_per_task, busiest_nr_running; |
2318 | unsigned long this_load_per_task, this_nr_running; | |
7897986b | 2319 | int load_idx; |
5c45bf27 SS |
2320 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) |
2321 | int power_savings_balance = 1; | |
2322 | unsigned long leader_nr_running = 0, min_load_per_task = 0; | |
2323 | unsigned long min_nr_running = ULONG_MAX; | |
2324 | struct sched_group *group_min = NULL, *group_leader = NULL; | |
2325 | #endif | |
1da177e4 LT |
2326 | |
2327 | max_load = this_load = total_load = total_pwr = 0; | |
2dd73a4f PW |
2328 | busiest_load_per_task = busiest_nr_running = 0; |
2329 | this_load_per_task = this_nr_running = 0; | |
d15bcfdb | 2330 | if (idle == CPU_NOT_IDLE) |
7897986b | 2331 | load_idx = sd->busy_idx; |
d15bcfdb | 2332 | else if (idle == CPU_NEWLY_IDLE) |
7897986b NP |
2333 | load_idx = sd->newidle_idx; |
2334 | else | |
2335 | load_idx = sd->idle_idx; | |
1da177e4 LT |
2336 | |
2337 | do { | |
5c45bf27 | 2338 | unsigned long load, group_capacity; |
1da177e4 LT |
2339 | int local_group; |
2340 | int i; | |
783609c6 | 2341 | unsigned int balance_cpu = -1, first_idle_cpu = 0; |
2dd73a4f | 2342 | unsigned long sum_nr_running, sum_weighted_load; |
1da177e4 LT |
2343 | |
2344 | local_group = cpu_isset(this_cpu, group->cpumask); | |
2345 | ||
783609c6 SS |
2346 | if (local_group) |
2347 | balance_cpu = first_cpu(group->cpumask); | |
2348 | ||
1da177e4 | 2349 | /* Tally up the load of all CPUs in the group */ |
2dd73a4f | 2350 | sum_weighted_load = sum_nr_running = avg_load = 0; |
1da177e4 LT |
2351 | |
2352 | for_each_cpu_mask(i, group->cpumask) { | |
0a2966b4 CL |
2353 | struct rq *rq; |
2354 | ||
2355 | if (!cpu_isset(i, *cpus)) | |
2356 | continue; | |
2357 | ||
2358 | rq = cpu_rq(i); | |
2dd73a4f | 2359 | |
9439aab8 | 2360 | if (*sd_idle && rq->nr_running) |
5969fe06 NP |
2361 | *sd_idle = 0; |
2362 | ||
1da177e4 | 2363 | /* Bias balancing toward cpus of our domain */ |
783609c6 SS |
2364 | if (local_group) { |
2365 | if (idle_cpu(i) && !first_idle_cpu) { | |
2366 | first_idle_cpu = 1; | |
2367 | balance_cpu = i; | |
2368 | } | |
2369 | ||
a2000572 | 2370 | load = target_load(i, load_idx); |
783609c6 | 2371 | } else |
a2000572 | 2372 | load = source_load(i, load_idx); |
1da177e4 LT |
2373 | |
2374 | avg_load += load; | |
2dd73a4f | 2375 | sum_nr_running += rq->nr_running; |
dd41f596 | 2376 | sum_weighted_load += weighted_cpuload(i); |
1da177e4 LT |
2377 | } |
2378 | ||
783609c6 SS |
2379 | /* |
2380 | * First idle cpu or the first cpu(busiest) in this sched group | |
2381 | * is eligible for doing load balancing at this and above | |
9439aab8 SS |
2382 | * domains. In the newly idle case, we will allow all the cpu's |
2383 | * to do the newly idle load balance. | |
783609c6 | 2384 | */ |
9439aab8 SS |
2385 | if (idle != CPU_NEWLY_IDLE && local_group && |
2386 | balance_cpu != this_cpu && balance) { | |
783609c6 SS |
2387 | *balance = 0; |
2388 | goto ret; | |
2389 | } | |
2390 | ||
1da177e4 | 2391 | total_load += avg_load; |
5517d86b | 2392 | total_pwr += group->__cpu_power; |
1da177e4 LT |
2393 | |
2394 | /* Adjust by relative CPU power of the group */ | |
5517d86b ED |
2395 | avg_load = sg_div_cpu_power(group, |
2396 | avg_load * SCHED_LOAD_SCALE); | |
1da177e4 | 2397 | |
5517d86b | 2398 | group_capacity = group->__cpu_power / SCHED_LOAD_SCALE; |
5c45bf27 | 2399 | |
1da177e4 LT |
2400 | if (local_group) { |
2401 | this_load = avg_load; | |
2402 | this = group; | |
2dd73a4f PW |
2403 | this_nr_running = sum_nr_running; |
2404 | this_load_per_task = sum_weighted_load; | |
2405 | } else if (avg_load > max_load && | |
5c45bf27 | 2406 | sum_nr_running > group_capacity) { |
1da177e4 LT |
2407 | max_load = avg_load; |
2408 | busiest = group; | |
2dd73a4f PW |
2409 | busiest_nr_running = sum_nr_running; |
2410 | busiest_load_per_task = sum_weighted_load; | |
1da177e4 | 2411 | } |
5c45bf27 SS |
2412 | |
2413 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) | |
2414 | /* | |
2415 | * Busy processors will not participate in power savings | |
2416 | * balance. | |
2417 | */ | |
dd41f596 IM |
2418 | if (idle == CPU_NOT_IDLE || |
2419 | !(sd->flags & SD_POWERSAVINGS_BALANCE)) | |
2420 | goto group_next; | |
5c45bf27 SS |
2421 | |
2422 | /* | |
2423 | * If the local group is idle or completely loaded | |
2424 | * no need to do power savings balance at this domain | |
2425 | */ | |
2426 | if (local_group && (this_nr_running >= group_capacity || | |
2427 | !this_nr_running)) | |
2428 | power_savings_balance = 0; | |
2429 | ||
dd41f596 | 2430 | /* |
5c45bf27 SS |
2431 | * If a group is already running at full capacity or idle, |
2432 | * don't include that group in power savings calculations | |
dd41f596 IM |
2433 | */ |
2434 | if (!power_savings_balance || sum_nr_running >= group_capacity | |
5c45bf27 | 2435 | || !sum_nr_running) |
dd41f596 | 2436 | goto group_next; |
5c45bf27 | 2437 | |
dd41f596 | 2438 | /* |
5c45bf27 | 2439 | * Calculate the group which has the least non-idle load. |
dd41f596 IM |
2440 | * This is the group from where we need to pick up the load |
2441 | * for saving power | |
2442 | */ | |
2443 | if ((sum_nr_running < min_nr_running) || | |
2444 | (sum_nr_running == min_nr_running && | |
5c45bf27 SS |
2445 | first_cpu(group->cpumask) < |
2446 | first_cpu(group_min->cpumask))) { | |
dd41f596 IM |
2447 | group_min = group; |
2448 | min_nr_running = sum_nr_running; | |
5c45bf27 SS |
2449 | min_load_per_task = sum_weighted_load / |
2450 | sum_nr_running; | |
dd41f596 | 2451 | } |
5c45bf27 | 2452 | |
dd41f596 | 2453 | /* |
5c45bf27 | 2454 | * Calculate the group which is almost near its |
dd41f596 IM |
2455 | * capacity but still has some space to pick up some load |
2456 | * from other group and save more power | |
2457 | */ | |
2458 | if (sum_nr_running <= group_capacity - 1) { | |
2459 | if (sum_nr_running > leader_nr_running || | |
2460 | (sum_nr_running == leader_nr_running && | |
2461 | first_cpu(group->cpumask) > | |
2462 | first_cpu(group_leader->cpumask))) { | |
2463 | group_leader = group; | |
2464 | leader_nr_running = sum_nr_running; | |
2465 | } | |
48f24c4d | 2466 | } |
5c45bf27 SS |
2467 | group_next: |
2468 | #endif | |
1da177e4 LT |
2469 | group = group->next; |
2470 | } while (group != sd->groups); | |
2471 | ||
2dd73a4f | 2472 | if (!busiest || this_load >= max_load || busiest_nr_running == 0) |
1da177e4 LT |
2473 | goto out_balanced; |
2474 | ||
2475 | avg_load = (SCHED_LOAD_SCALE * total_load) / total_pwr; | |
2476 | ||
2477 | if (this_load >= avg_load || | |
2478 | 100*max_load <= sd->imbalance_pct*this_load) | |
2479 | goto out_balanced; | |
2480 | ||
2dd73a4f | 2481 | busiest_load_per_task /= busiest_nr_running; |
1da177e4 LT |
2482 | /* |
2483 | * We're trying to get all the cpus to the average_load, so we don't | |
2484 | * want to push ourselves above the average load, nor do we wish to | |
2485 | * reduce the max loaded cpu below the average load, as either of these | |
2486 | * actions would just result in more rebalancing later, and ping-pong | |
2487 | * tasks around. Thus we look for the minimum possible imbalance. | |
2488 | * Negative imbalances (*we* are more loaded than anyone else) will | |
2489 | * be counted as no imbalance for these purposes -- we can't fix that | |
2490 | * by pulling tasks to us. Be careful of negative numbers as they'll | |
2491 | * appear as very large values with unsigned longs. | |
2492 | */ | |
2dd73a4f PW |
2493 | if (max_load <= busiest_load_per_task) |
2494 | goto out_balanced; | |
2495 | ||
2496 | /* | |
2497 | * In the presence of smp nice balancing, certain scenarios can have | |
2498 | * max load less than avg load(as we skip the groups at or below | |
2499 | * its cpu_power, while calculating max_load..) | |
2500 | */ | |
2501 | if (max_load < avg_load) { | |
2502 | *imbalance = 0; | |
2503 | goto small_imbalance; | |
2504 | } | |
0c117f1b SS |
2505 | |
2506 | /* Don't want to pull so many tasks that a group would go idle */ | |
2dd73a4f | 2507 | max_pull = min(max_load - avg_load, max_load - busiest_load_per_task); |
0c117f1b | 2508 | |
1da177e4 | 2509 | /* How much load to actually move to equalise the imbalance */ |
5517d86b ED |
2510 | *imbalance = min(max_pull * busiest->__cpu_power, |
2511 | (avg_load - this_load) * this->__cpu_power) | |
1da177e4 LT |
2512 | / SCHED_LOAD_SCALE; |
2513 | ||
2dd73a4f PW |
2514 | /* |
2515 | * if *imbalance is less than the average load per runnable task | |
2516 | * there is no gaurantee that any tasks will be moved so we'll have | |
2517 | * a think about bumping its value to force at least one task to be | |
2518 | * moved | |
2519 | */ | |
dd41f596 | 2520 | if (*imbalance + SCHED_LOAD_SCALE_FUZZ < busiest_load_per_task/2) { |
48f24c4d | 2521 | unsigned long tmp, pwr_now, pwr_move; |
2dd73a4f PW |
2522 | unsigned int imbn; |
2523 | ||
2524 | small_imbalance: | |
2525 | pwr_move = pwr_now = 0; | |
2526 | imbn = 2; | |
2527 | if (this_nr_running) { | |
2528 | this_load_per_task /= this_nr_running; | |
2529 | if (busiest_load_per_task > this_load_per_task) | |
2530 | imbn = 1; | |
2531 | } else | |
2532 | this_load_per_task = SCHED_LOAD_SCALE; | |
1da177e4 | 2533 | |
dd41f596 IM |
2534 | if (max_load - this_load + SCHED_LOAD_SCALE_FUZZ >= |
2535 | busiest_load_per_task * imbn) { | |
2dd73a4f | 2536 | *imbalance = busiest_load_per_task; |
1da177e4 LT |
2537 | return busiest; |
2538 | } | |
2539 | ||
2540 | /* | |
2541 | * OK, we don't have enough imbalance to justify moving tasks, | |
2542 | * however we may be able to increase total CPU power used by | |
2543 | * moving them. | |
2544 | */ | |
2545 | ||
5517d86b ED |
2546 | pwr_now += busiest->__cpu_power * |
2547 | min(busiest_load_per_task, max_load); | |
2548 | pwr_now += this->__cpu_power * | |
2549 | min(this_load_per_task, this_load); | |
1da177e4 LT |
2550 | pwr_now /= SCHED_LOAD_SCALE; |
2551 | ||
2552 | /* Amount of load we'd subtract */ | |
5517d86b ED |
2553 | tmp = sg_div_cpu_power(busiest, |
2554 | busiest_load_per_task * SCHED_LOAD_SCALE); | |
1da177e4 | 2555 | if (max_load > tmp) |
5517d86b | 2556 | pwr_move += busiest->__cpu_power * |
2dd73a4f | 2557 | min(busiest_load_per_task, max_load - tmp); |
1da177e4 LT |
2558 | |
2559 | /* Amount of load we'd add */ | |
5517d86b | 2560 | if (max_load * busiest->__cpu_power < |
33859f7f | 2561 | busiest_load_per_task * SCHED_LOAD_SCALE) |
5517d86b ED |
2562 | tmp = sg_div_cpu_power(this, |
2563 | max_load * busiest->__cpu_power); | |
1da177e4 | 2564 | else |
5517d86b ED |
2565 | tmp = sg_div_cpu_power(this, |
2566 | busiest_load_per_task * SCHED_LOAD_SCALE); | |
2567 | pwr_move += this->__cpu_power * | |
2568 | min(this_load_per_task, this_load + tmp); | |
1da177e4 LT |
2569 | pwr_move /= SCHED_LOAD_SCALE; |
2570 | ||
2571 | /* Move if we gain throughput */ | |
2572 | if (pwr_move <= pwr_now) | |
2573 | goto out_balanced; | |
2574 | ||
2dd73a4f | 2575 | *imbalance = busiest_load_per_task; |
1da177e4 LT |
2576 | } |
2577 | ||
1da177e4 LT |
2578 | return busiest; |
2579 | ||
2580 | out_balanced: | |
5c45bf27 | 2581 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) |
d15bcfdb | 2582 | if (idle == CPU_NOT_IDLE || !(sd->flags & SD_POWERSAVINGS_BALANCE)) |
5c45bf27 | 2583 | goto ret; |
1da177e4 | 2584 | |
5c45bf27 SS |
2585 | if (this == group_leader && group_leader != group_min) { |
2586 | *imbalance = min_load_per_task; | |
2587 | return group_min; | |
2588 | } | |
5c45bf27 | 2589 | #endif |
783609c6 | 2590 | ret: |
1da177e4 LT |
2591 | *imbalance = 0; |
2592 | return NULL; | |
2593 | } | |
2594 | ||
2595 | /* | |
2596 | * find_busiest_queue - find the busiest runqueue among the cpus in group. | |
2597 | */ | |
70b97a7f | 2598 | static struct rq * |
d15bcfdb | 2599 | find_busiest_queue(struct sched_group *group, enum cpu_idle_type idle, |
0a2966b4 | 2600 | unsigned long imbalance, cpumask_t *cpus) |
1da177e4 | 2601 | { |
70b97a7f | 2602 | struct rq *busiest = NULL, *rq; |
2dd73a4f | 2603 | unsigned long max_load = 0; |
1da177e4 LT |
2604 | int i; |
2605 | ||
2606 | for_each_cpu_mask(i, group->cpumask) { | |
dd41f596 | 2607 | unsigned long wl; |
0a2966b4 CL |
2608 | |
2609 | if (!cpu_isset(i, *cpus)) | |
2610 | continue; | |
2611 | ||
48f24c4d | 2612 | rq = cpu_rq(i); |
dd41f596 | 2613 | wl = weighted_cpuload(i); |
2dd73a4f | 2614 | |
dd41f596 | 2615 | if (rq->nr_running == 1 && wl > imbalance) |
2dd73a4f | 2616 | continue; |
1da177e4 | 2617 | |
dd41f596 IM |
2618 | if (wl > max_load) { |
2619 | max_load = wl; | |
48f24c4d | 2620 | busiest = rq; |
1da177e4 LT |
2621 | } |
2622 | } | |
2623 | ||
2624 | return busiest; | |
2625 | } | |
2626 | ||
77391d71 NP |
2627 | /* |
2628 | * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but | |
2629 | * so long as it is large enough. | |
2630 | */ | |
2631 | #define MAX_PINNED_INTERVAL 512 | |
2632 | ||
1da177e4 LT |
2633 | /* |
2634 | * Check this_cpu to ensure it is balanced within domain. Attempt to move | |
2635 | * tasks if there is an imbalance. | |
1da177e4 | 2636 | */ |
70b97a7f | 2637 | static int load_balance(int this_cpu, struct rq *this_rq, |
d15bcfdb | 2638 | struct sched_domain *sd, enum cpu_idle_type idle, |
783609c6 | 2639 | int *balance) |
1da177e4 | 2640 | { |
43010659 | 2641 | int ld_moved, all_pinned = 0, active_balance = 0, sd_idle = 0; |
1da177e4 | 2642 | struct sched_group *group; |
1da177e4 | 2643 | unsigned long imbalance; |
70b97a7f | 2644 | struct rq *busiest; |
0a2966b4 | 2645 | cpumask_t cpus = CPU_MASK_ALL; |
fe2eea3f | 2646 | unsigned long flags; |
5969fe06 | 2647 | |
89c4710e SS |
2648 | /* |
2649 | * When power savings policy is enabled for the parent domain, idle | |
2650 | * sibling can pick up load irrespective of busy siblings. In this case, | |
dd41f596 | 2651 | * let the state of idle sibling percolate up as CPU_IDLE, instead of |
d15bcfdb | 2652 | * portraying it as CPU_NOT_IDLE. |
89c4710e | 2653 | */ |
d15bcfdb | 2654 | if (idle != CPU_NOT_IDLE && sd->flags & SD_SHARE_CPUPOWER && |
89c4710e | 2655 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
5969fe06 | 2656 | sd_idle = 1; |
1da177e4 | 2657 | |
1da177e4 LT |
2658 | schedstat_inc(sd, lb_cnt[idle]); |
2659 | ||
0a2966b4 CL |
2660 | redo: |
2661 | group = find_busiest_group(sd, this_cpu, &imbalance, idle, &sd_idle, | |
783609c6 SS |
2662 | &cpus, balance); |
2663 | ||
06066714 | 2664 | if (*balance == 0) |
783609c6 | 2665 | goto out_balanced; |
783609c6 | 2666 | |
1da177e4 LT |
2667 | if (!group) { |
2668 | schedstat_inc(sd, lb_nobusyg[idle]); | |
2669 | goto out_balanced; | |
2670 | } | |
2671 | ||
0a2966b4 | 2672 | busiest = find_busiest_queue(group, idle, imbalance, &cpus); |
1da177e4 LT |
2673 | if (!busiest) { |
2674 | schedstat_inc(sd, lb_nobusyq[idle]); | |
2675 | goto out_balanced; | |
2676 | } | |
2677 | ||
db935dbd | 2678 | BUG_ON(busiest == this_rq); |
1da177e4 LT |
2679 | |
2680 | schedstat_add(sd, lb_imbalance[idle], imbalance); | |
2681 | ||
43010659 | 2682 | ld_moved = 0; |
1da177e4 LT |
2683 | if (busiest->nr_running > 1) { |
2684 | /* | |
2685 | * Attempt to move tasks. If find_busiest_group has found | |
2686 | * an imbalance but busiest->nr_running <= 1, the group is | |
43010659 | 2687 | * still unbalanced. ld_moved simply stays zero, so it is |
1da177e4 LT |
2688 | * correctly treated as an imbalance. |
2689 | */ | |
fe2eea3f | 2690 | local_irq_save(flags); |
e17224bf | 2691 | double_rq_lock(this_rq, busiest); |
43010659 | 2692 | ld_moved = move_tasks(this_rq, this_cpu, busiest, |
48f24c4d | 2693 | imbalance, sd, idle, &all_pinned); |
e17224bf | 2694 | double_rq_unlock(this_rq, busiest); |
fe2eea3f | 2695 | local_irq_restore(flags); |
81026794 | 2696 | |
46cb4b7c SS |
2697 | /* |
2698 | * some other cpu did the load balance for us. | |
2699 | */ | |
43010659 | 2700 | if (ld_moved && this_cpu != smp_processor_id()) |
46cb4b7c SS |
2701 | resched_cpu(this_cpu); |
2702 | ||
81026794 | 2703 | /* All tasks on this runqueue were pinned by CPU affinity */ |
0a2966b4 CL |
2704 | if (unlikely(all_pinned)) { |
2705 | cpu_clear(cpu_of(busiest), cpus); | |
2706 | if (!cpus_empty(cpus)) | |
2707 | goto redo; | |
81026794 | 2708 | goto out_balanced; |
0a2966b4 | 2709 | } |
1da177e4 | 2710 | } |
81026794 | 2711 | |
43010659 | 2712 | if (!ld_moved) { |
1da177e4 LT |
2713 | schedstat_inc(sd, lb_failed[idle]); |
2714 | sd->nr_balance_failed++; | |
2715 | ||
2716 | if (unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2)) { | |
1da177e4 | 2717 | |
fe2eea3f | 2718 | spin_lock_irqsave(&busiest->lock, flags); |
fa3b6ddc SS |
2719 | |
2720 | /* don't kick the migration_thread, if the curr | |
2721 | * task on busiest cpu can't be moved to this_cpu | |
2722 | */ | |
2723 | if (!cpu_isset(this_cpu, busiest->curr->cpus_allowed)) { | |
fe2eea3f | 2724 | spin_unlock_irqrestore(&busiest->lock, flags); |
fa3b6ddc SS |
2725 | all_pinned = 1; |
2726 | goto out_one_pinned; | |
2727 | } | |
2728 | ||
1da177e4 LT |
2729 | if (!busiest->active_balance) { |
2730 | busiest->active_balance = 1; | |
2731 | busiest->push_cpu = this_cpu; | |
81026794 | 2732 | active_balance = 1; |
1da177e4 | 2733 | } |
fe2eea3f | 2734 | spin_unlock_irqrestore(&busiest->lock, flags); |
81026794 | 2735 | if (active_balance) |
1da177e4 LT |
2736 | wake_up_process(busiest->migration_thread); |
2737 | ||
2738 | /* | |
2739 | * We've kicked active balancing, reset the failure | |
2740 | * counter. | |
2741 | */ | |
39507451 | 2742 | sd->nr_balance_failed = sd->cache_nice_tries+1; |
1da177e4 | 2743 | } |
81026794 | 2744 | } else |
1da177e4 LT |
2745 | sd->nr_balance_failed = 0; |
2746 | ||
81026794 | 2747 | if (likely(!active_balance)) { |
1da177e4 LT |
2748 | /* We were unbalanced, so reset the balancing interval */ |
2749 | sd->balance_interval = sd->min_interval; | |
81026794 NP |
2750 | } else { |
2751 | /* | |
2752 | * If we've begun active balancing, start to back off. This | |
2753 | * case may not be covered by the all_pinned logic if there | |
2754 | * is only 1 task on the busy runqueue (because we don't call | |
2755 | * move_tasks). | |
2756 | */ | |
2757 | if (sd->balance_interval < sd->max_interval) | |
2758 | sd->balance_interval *= 2; | |
1da177e4 LT |
2759 | } |
2760 | ||
43010659 | 2761 | if (!ld_moved && !sd_idle && sd->flags & SD_SHARE_CPUPOWER && |
89c4710e | 2762 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
5969fe06 | 2763 | return -1; |
43010659 | 2764 | return ld_moved; |
1da177e4 LT |
2765 | |
2766 | out_balanced: | |
1da177e4 LT |
2767 | schedstat_inc(sd, lb_balanced[idle]); |
2768 | ||
16cfb1c0 | 2769 | sd->nr_balance_failed = 0; |
fa3b6ddc SS |
2770 | |
2771 | out_one_pinned: | |
1da177e4 | 2772 | /* tune up the balancing interval */ |
77391d71 NP |
2773 | if ((all_pinned && sd->balance_interval < MAX_PINNED_INTERVAL) || |
2774 | (sd->balance_interval < sd->max_interval)) | |
1da177e4 LT |
2775 | sd->balance_interval *= 2; |
2776 | ||
48f24c4d | 2777 | if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && |
89c4710e | 2778 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
5969fe06 | 2779 | return -1; |
1da177e4 LT |
2780 | return 0; |
2781 | } | |
2782 | ||
2783 | /* | |
2784 | * Check this_cpu to ensure it is balanced within domain. Attempt to move | |
2785 | * tasks if there is an imbalance. | |
2786 | * | |
d15bcfdb | 2787 | * Called from schedule when this_rq is about to become idle (CPU_NEWLY_IDLE). |
1da177e4 LT |
2788 | * this_rq is locked. |
2789 | */ | |
48f24c4d | 2790 | static int |
70b97a7f | 2791 | load_balance_newidle(int this_cpu, struct rq *this_rq, struct sched_domain *sd) |
1da177e4 LT |
2792 | { |
2793 | struct sched_group *group; | |
70b97a7f | 2794 | struct rq *busiest = NULL; |
1da177e4 | 2795 | unsigned long imbalance; |
43010659 | 2796 | int ld_moved = 0; |
5969fe06 | 2797 | int sd_idle = 0; |
969bb4e4 | 2798 | int all_pinned = 0; |
0a2966b4 | 2799 | cpumask_t cpus = CPU_MASK_ALL; |
5969fe06 | 2800 | |
89c4710e SS |
2801 | /* |
2802 | * When power savings policy is enabled for the parent domain, idle | |
2803 | * sibling can pick up load irrespective of busy siblings. In this case, | |
2804 | * let the state of idle sibling percolate up as IDLE, instead of | |
d15bcfdb | 2805 | * portraying it as CPU_NOT_IDLE. |
89c4710e SS |
2806 | */ |
2807 | if (sd->flags & SD_SHARE_CPUPOWER && | |
2808 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) | |
5969fe06 | 2809 | sd_idle = 1; |
1da177e4 | 2810 | |
d15bcfdb | 2811 | schedstat_inc(sd, lb_cnt[CPU_NEWLY_IDLE]); |
0a2966b4 | 2812 | redo: |
d15bcfdb | 2813 | group = find_busiest_group(sd, this_cpu, &imbalance, CPU_NEWLY_IDLE, |
783609c6 | 2814 | &sd_idle, &cpus, NULL); |
1da177e4 | 2815 | if (!group) { |
d15bcfdb | 2816 | schedstat_inc(sd, lb_nobusyg[CPU_NEWLY_IDLE]); |
16cfb1c0 | 2817 | goto out_balanced; |
1da177e4 LT |
2818 | } |
2819 | ||
d15bcfdb | 2820 | busiest = find_busiest_queue(group, CPU_NEWLY_IDLE, imbalance, |
0a2966b4 | 2821 | &cpus); |
db935dbd | 2822 | if (!busiest) { |
d15bcfdb | 2823 | schedstat_inc(sd, lb_nobusyq[CPU_NEWLY_IDLE]); |
16cfb1c0 | 2824 | goto out_balanced; |
1da177e4 LT |
2825 | } |
2826 | ||
db935dbd NP |
2827 | BUG_ON(busiest == this_rq); |
2828 | ||
d15bcfdb | 2829 | schedstat_add(sd, lb_imbalance[CPU_NEWLY_IDLE], imbalance); |
d6d5cfaf | 2830 | |
43010659 | 2831 | ld_moved = 0; |
d6d5cfaf NP |
2832 | if (busiest->nr_running > 1) { |
2833 | /* Attempt to move tasks */ | |
2834 | double_lock_balance(this_rq, busiest); | |
6e82a3be IM |
2835 | /* this_rq->clock is already updated */ |
2836 | update_rq_clock(busiest); | |
43010659 | 2837 | ld_moved = move_tasks(this_rq, this_cpu, busiest, |
969bb4e4 SS |
2838 | imbalance, sd, CPU_NEWLY_IDLE, |
2839 | &all_pinned); | |
d6d5cfaf | 2840 | spin_unlock(&busiest->lock); |
0a2966b4 | 2841 | |
969bb4e4 | 2842 | if (unlikely(all_pinned)) { |
0a2966b4 CL |
2843 | cpu_clear(cpu_of(busiest), cpus); |
2844 | if (!cpus_empty(cpus)) | |
2845 | goto redo; | |
2846 | } | |
d6d5cfaf NP |
2847 | } |
2848 | ||
43010659 | 2849 | if (!ld_moved) { |
d15bcfdb | 2850 | schedstat_inc(sd, lb_failed[CPU_NEWLY_IDLE]); |
89c4710e SS |
2851 | if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && |
2852 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) | |
5969fe06 NP |
2853 | return -1; |
2854 | } else | |
16cfb1c0 | 2855 | sd->nr_balance_failed = 0; |
1da177e4 | 2856 | |
43010659 | 2857 | return ld_moved; |
16cfb1c0 NP |
2858 | |
2859 | out_balanced: | |
d15bcfdb | 2860 | schedstat_inc(sd, lb_balanced[CPU_NEWLY_IDLE]); |
48f24c4d | 2861 | if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && |
89c4710e | 2862 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
5969fe06 | 2863 | return -1; |
16cfb1c0 | 2864 | sd->nr_balance_failed = 0; |
48f24c4d | 2865 | |
16cfb1c0 | 2866 | return 0; |
1da177e4 LT |
2867 | } |
2868 | ||
2869 | /* | |
2870 | * idle_balance is called by schedule() if this_cpu is about to become | |
2871 | * idle. Attempts to pull tasks from other CPUs. | |
2872 | */ | |
70b97a7f | 2873 | static void idle_balance(int this_cpu, struct rq *this_rq) |
1da177e4 LT |
2874 | { |
2875 | struct sched_domain *sd; | |
dd41f596 IM |
2876 | int pulled_task = -1; |
2877 | unsigned long next_balance = jiffies + HZ; | |
1da177e4 LT |
2878 | |
2879 | for_each_domain(this_cpu, sd) { | |
92c4ca5c CL |
2880 | unsigned long interval; |
2881 | ||
2882 | if (!(sd->flags & SD_LOAD_BALANCE)) | |
2883 | continue; | |
2884 | ||
2885 | if (sd->flags & SD_BALANCE_NEWIDLE) | |
48f24c4d | 2886 | /* If we've pulled tasks over stop searching: */ |
1bd77f2d | 2887 | pulled_task = load_balance_newidle(this_cpu, |
92c4ca5c CL |
2888 | this_rq, sd); |
2889 | ||
2890 | interval = msecs_to_jiffies(sd->balance_interval); | |
2891 | if (time_after(next_balance, sd->last_balance + interval)) | |
2892 | next_balance = sd->last_balance + interval; | |
2893 | if (pulled_task) | |
2894 | break; | |
1da177e4 | 2895 | } |
dd41f596 | 2896 | if (pulled_task || time_after(jiffies, this_rq->next_balance)) { |
1bd77f2d CL |
2897 | /* |
2898 | * We are going idle. next_balance may be set based on | |
2899 | * a busy processor. So reset next_balance. | |
2900 | */ | |
2901 | this_rq->next_balance = next_balance; | |
dd41f596 | 2902 | } |
1da177e4 LT |
2903 | } |
2904 | ||
2905 | /* | |
2906 | * active_load_balance is run by migration threads. It pushes running tasks | |
2907 | * off the busiest CPU onto idle CPUs. It requires at least 1 task to be | |
2908 | * running on each physical CPU where possible, and avoids physical / | |
2909 | * logical imbalances. | |
2910 | * | |
2911 | * Called with busiest_rq locked. | |
2912 | */ | |
70b97a7f | 2913 | static void active_load_balance(struct rq *busiest_rq, int busiest_cpu) |
1da177e4 | 2914 | { |
39507451 | 2915 | int target_cpu = busiest_rq->push_cpu; |
70b97a7f IM |
2916 | struct sched_domain *sd; |
2917 | struct rq *target_rq; | |
39507451 | 2918 | |
48f24c4d | 2919 | /* Is there any task to move? */ |
39507451 | 2920 | if (busiest_rq->nr_running <= 1) |
39507451 NP |
2921 | return; |
2922 | ||
2923 | target_rq = cpu_rq(target_cpu); | |
1da177e4 LT |
2924 | |
2925 | /* | |
39507451 NP |
2926 | * This condition is "impossible", if it occurs |
2927 | * we need to fix it. Originally reported by | |
2928 | * Bjorn Helgaas on a 128-cpu setup. | |
1da177e4 | 2929 | */ |
39507451 | 2930 | BUG_ON(busiest_rq == target_rq); |
1da177e4 | 2931 | |
39507451 NP |
2932 | /* move a task from busiest_rq to target_rq */ |
2933 | double_lock_balance(busiest_rq, target_rq); | |
6e82a3be IM |
2934 | update_rq_clock(busiest_rq); |
2935 | update_rq_clock(target_rq); | |
39507451 NP |
2936 | |
2937 | /* Search for an sd spanning us and the target CPU. */ | |
c96d145e | 2938 | for_each_domain(target_cpu, sd) { |
39507451 | 2939 | if ((sd->flags & SD_LOAD_BALANCE) && |
48f24c4d | 2940 | cpu_isset(busiest_cpu, sd->span)) |
39507451 | 2941 | break; |
c96d145e | 2942 | } |
39507451 | 2943 | |
48f24c4d IM |
2944 | if (likely(sd)) { |
2945 | schedstat_inc(sd, alb_cnt); | |
39507451 | 2946 | |
43010659 PW |
2947 | if (move_one_task(target_rq, target_cpu, busiest_rq, |
2948 | sd, CPU_IDLE)) | |
48f24c4d IM |
2949 | schedstat_inc(sd, alb_pushed); |
2950 | else | |
2951 | schedstat_inc(sd, alb_failed); | |
2952 | } | |
39507451 | 2953 | spin_unlock(&target_rq->lock); |
1da177e4 LT |
2954 | } |
2955 | ||
46cb4b7c SS |
2956 | #ifdef CONFIG_NO_HZ |
2957 | static struct { | |
2958 | atomic_t load_balancer; | |
2959 | cpumask_t cpu_mask; | |
2960 | } nohz ____cacheline_aligned = { | |
2961 | .load_balancer = ATOMIC_INIT(-1), | |
2962 | .cpu_mask = CPU_MASK_NONE, | |
2963 | }; | |
2964 | ||
7835b98b | 2965 | /* |
46cb4b7c SS |
2966 | * This routine will try to nominate the ilb (idle load balancing) |
2967 | * owner among the cpus whose ticks are stopped. ilb owner will do the idle | |
2968 | * load balancing on behalf of all those cpus. If all the cpus in the system | |
2969 | * go into this tickless mode, then there will be no ilb owner (as there is | |
2970 | * no need for one) and all the cpus will sleep till the next wakeup event | |
2971 | * arrives... | |
2972 | * | |
2973 | * For the ilb owner, tick is not stopped. And this tick will be used | |
2974 | * for idle load balancing. ilb owner will still be part of | |
2975 | * nohz.cpu_mask.. | |
7835b98b | 2976 | * |
46cb4b7c SS |
2977 | * While stopping the tick, this cpu will become the ilb owner if there |
2978 | * is no other owner. And will be the owner till that cpu becomes busy | |
2979 | * or if all cpus in the system stop their ticks at which point | |
2980 | * there is no need for ilb owner. | |
2981 | * | |
2982 | * When the ilb owner becomes busy, it nominates another owner, during the | |
2983 | * next busy scheduler_tick() | |
2984 | */ | |
2985 | int select_nohz_load_balancer(int stop_tick) | |
2986 | { | |
2987 | int cpu = smp_processor_id(); | |
2988 | ||
2989 | if (stop_tick) { | |
2990 | cpu_set(cpu, nohz.cpu_mask); | |
2991 | cpu_rq(cpu)->in_nohz_recently = 1; | |
2992 | ||
2993 | /* | |
2994 | * If we are going offline and still the leader, give up! | |
2995 | */ | |
2996 | if (cpu_is_offline(cpu) && | |
2997 | atomic_read(&nohz.load_balancer) == cpu) { | |
2998 | if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu) | |
2999 | BUG(); | |
3000 | return 0; | |
3001 | } | |
3002 | ||
3003 | /* time for ilb owner also to sleep */ | |
3004 | if (cpus_weight(nohz.cpu_mask) == num_online_cpus()) { | |
3005 | if (atomic_read(&nohz.load_balancer) == cpu) | |
3006 | atomic_set(&nohz.load_balancer, -1); | |
3007 | return 0; | |
3008 | } | |
3009 | ||
3010 | if (atomic_read(&nohz.load_balancer) == -1) { | |
3011 | /* make me the ilb owner */ | |
3012 | if (atomic_cmpxchg(&nohz.load_balancer, -1, cpu) == -1) | |
3013 | return 1; | |
3014 | } else if (atomic_read(&nohz.load_balancer) == cpu) | |
3015 | return 1; | |
3016 | } else { | |
3017 | if (!cpu_isset(cpu, nohz.cpu_mask)) | |
3018 | return 0; | |
3019 | ||
3020 | cpu_clear(cpu, nohz.cpu_mask); | |
3021 | ||
3022 | if (atomic_read(&nohz.load_balancer) == cpu) | |
3023 | if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu) | |
3024 | BUG(); | |
3025 | } | |
3026 | return 0; | |
3027 | } | |
3028 | #endif | |
3029 | ||
3030 | static DEFINE_SPINLOCK(balancing); | |
3031 | ||
3032 | /* | |
7835b98b CL |
3033 | * It checks each scheduling domain to see if it is due to be balanced, |
3034 | * and initiates a balancing operation if so. | |
3035 | * | |
3036 | * Balancing parameters are set up in arch_init_sched_domains. | |
3037 | */ | |
d15bcfdb | 3038 | static inline void rebalance_domains(int cpu, enum cpu_idle_type idle) |
7835b98b | 3039 | { |
46cb4b7c SS |
3040 | int balance = 1; |
3041 | struct rq *rq = cpu_rq(cpu); | |
7835b98b CL |
3042 | unsigned long interval; |
3043 | struct sched_domain *sd; | |
46cb4b7c | 3044 | /* Earliest time when we have to do rebalance again */ |
c9819f45 | 3045 | unsigned long next_balance = jiffies + 60*HZ; |
1da177e4 | 3046 | |
46cb4b7c | 3047 | for_each_domain(cpu, sd) { |
1da177e4 LT |
3048 | if (!(sd->flags & SD_LOAD_BALANCE)) |
3049 | continue; | |
3050 | ||
3051 | interval = sd->balance_interval; | |
d15bcfdb | 3052 | if (idle != CPU_IDLE) |
1da177e4 LT |
3053 | interval *= sd->busy_factor; |
3054 | ||
3055 | /* scale ms to jiffies */ | |
3056 | interval = msecs_to_jiffies(interval); | |
3057 | if (unlikely(!interval)) | |
3058 | interval = 1; | |
dd41f596 IM |
3059 | if (interval > HZ*NR_CPUS/10) |
3060 | interval = HZ*NR_CPUS/10; | |
3061 | ||
1da177e4 | 3062 | |
08c183f3 CL |
3063 | if (sd->flags & SD_SERIALIZE) { |
3064 | if (!spin_trylock(&balancing)) | |
3065 | goto out; | |
3066 | } | |
3067 | ||
c9819f45 | 3068 | if (time_after_eq(jiffies, sd->last_balance + interval)) { |
46cb4b7c | 3069 | if (load_balance(cpu, rq, sd, idle, &balance)) { |
fa3b6ddc SS |
3070 | /* |
3071 | * We've pulled tasks over so either we're no | |
5969fe06 NP |
3072 | * longer idle, or one of our SMT siblings is |
3073 | * not idle. | |
3074 | */ | |
d15bcfdb | 3075 | idle = CPU_NOT_IDLE; |
1da177e4 | 3076 | } |
1bd77f2d | 3077 | sd->last_balance = jiffies; |
1da177e4 | 3078 | } |
08c183f3 CL |
3079 | if (sd->flags & SD_SERIALIZE) |
3080 | spin_unlock(&balancing); | |
3081 | out: | |
c9819f45 CL |
3082 | if (time_after(next_balance, sd->last_balance + interval)) |
3083 | next_balance = sd->last_balance + interval; | |
783609c6 SS |
3084 | |
3085 | /* | |
3086 | * Stop the load balance at this level. There is another | |
3087 | * CPU in our sched group which is doing load balancing more | |
3088 | * actively. | |
3089 | */ | |
3090 | if (!balance) | |
3091 | break; | |
1da177e4 | 3092 | } |
46cb4b7c SS |
3093 | rq->next_balance = next_balance; |
3094 | } | |
3095 | ||
3096 | /* | |
3097 | * run_rebalance_domains is triggered when needed from the scheduler tick. | |
3098 | * In CONFIG_NO_HZ case, the idle load balance owner will do the | |
3099 | * rebalancing for all the cpus for whom scheduler ticks are stopped. | |
3100 | */ | |
3101 | static void run_rebalance_domains(struct softirq_action *h) | |
3102 | { | |
dd41f596 IM |
3103 | int this_cpu = smp_processor_id(); |
3104 | struct rq *this_rq = cpu_rq(this_cpu); | |
3105 | enum cpu_idle_type idle = this_rq->idle_at_tick ? | |
3106 | CPU_IDLE : CPU_NOT_IDLE; | |
46cb4b7c | 3107 | |
dd41f596 | 3108 | rebalance_domains(this_cpu, idle); |
46cb4b7c SS |
3109 | |
3110 | #ifdef CONFIG_NO_HZ | |
3111 | /* | |
3112 | * If this cpu is the owner for idle load balancing, then do the | |
3113 | * balancing on behalf of the other idle cpus whose ticks are | |
3114 | * stopped. | |
3115 | */ | |
dd41f596 IM |
3116 | if (this_rq->idle_at_tick && |
3117 | atomic_read(&nohz.load_balancer) == this_cpu) { | |
46cb4b7c SS |
3118 | cpumask_t cpus = nohz.cpu_mask; |
3119 | struct rq *rq; | |
3120 | int balance_cpu; | |
3121 | ||
dd41f596 | 3122 | cpu_clear(this_cpu, cpus); |
46cb4b7c SS |
3123 | for_each_cpu_mask(balance_cpu, cpus) { |
3124 | /* | |
3125 | * If this cpu gets work to do, stop the load balancing | |
3126 | * work being done for other cpus. Next load | |
3127 | * balancing owner will pick it up. | |
3128 | */ | |
3129 | if (need_resched()) | |
3130 | break; | |
3131 | ||
de0cf899 | 3132 | rebalance_domains(balance_cpu, CPU_IDLE); |
46cb4b7c SS |
3133 | |
3134 | rq = cpu_rq(balance_cpu); | |
dd41f596 IM |
3135 | if (time_after(this_rq->next_balance, rq->next_balance)) |
3136 | this_rq->next_balance = rq->next_balance; | |
46cb4b7c SS |
3137 | } |
3138 | } | |
3139 | #endif | |
3140 | } | |
3141 | ||
3142 | /* | |
3143 | * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing. | |
3144 | * | |
3145 | * In case of CONFIG_NO_HZ, this is the place where we nominate a new | |
3146 | * idle load balancing owner or decide to stop the periodic load balancing, | |
3147 | * if the whole system is idle. | |
3148 | */ | |
dd41f596 | 3149 | static inline void trigger_load_balance(struct rq *rq, int cpu) |
46cb4b7c | 3150 | { |
46cb4b7c SS |
3151 | #ifdef CONFIG_NO_HZ |
3152 | /* | |
3153 | * If we were in the nohz mode recently and busy at the current | |
3154 | * scheduler tick, then check if we need to nominate new idle | |
3155 | * load balancer. | |
3156 | */ | |
3157 | if (rq->in_nohz_recently && !rq->idle_at_tick) { | |
3158 | rq->in_nohz_recently = 0; | |
3159 | ||
3160 | if (atomic_read(&nohz.load_balancer) == cpu) { | |
3161 | cpu_clear(cpu, nohz.cpu_mask); | |
3162 | atomic_set(&nohz.load_balancer, -1); | |
3163 | } | |
3164 | ||
3165 | if (atomic_read(&nohz.load_balancer) == -1) { | |
3166 | /* | |
3167 | * simple selection for now: Nominate the | |
3168 | * first cpu in the nohz list to be the next | |
3169 | * ilb owner. | |
3170 | * | |
3171 | * TBD: Traverse the sched domains and nominate | |
3172 | * the nearest cpu in the nohz.cpu_mask. | |
3173 | */ | |
3174 | int ilb = first_cpu(nohz.cpu_mask); | |
3175 | ||
3176 | if (ilb != NR_CPUS) | |
3177 | resched_cpu(ilb); | |
3178 | } | |
3179 | } | |
3180 | ||
3181 | /* | |
3182 | * If this cpu is idle and doing idle load balancing for all the | |
3183 | * cpus with ticks stopped, is it time for that to stop? | |
3184 | */ | |
3185 | if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) == cpu && | |
3186 | cpus_weight(nohz.cpu_mask) == num_online_cpus()) { | |
3187 | resched_cpu(cpu); | |
3188 | return; | |
3189 | } | |
3190 | ||
3191 | /* | |
3192 | * If this cpu is idle and the idle load balancing is done by | |
3193 | * someone else, then no need raise the SCHED_SOFTIRQ | |
3194 | */ | |
3195 | if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) != cpu && | |
3196 | cpu_isset(cpu, nohz.cpu_mask)) | |
3197 | return; | |
3198 | #endif | |
3199 | if (time_after_eq(jiffies, rq->next_balance)) | |
3200 | raise_softirq(SCHED_SOFTIRQ); | |
1da177e4 | 3201 | } |
dd41f596 IM |
3202 | |
3203 | #else /* CONFIG_SMP */ | |
3204 | ||
1da177e4 LT |
3205 | /* |
3206 | * on UP we do not need to balance between CPUs: | |
3207 | */ | |
70b97a7f | 3208 | static inline void idle_balance(int cpu, struct rq *rq) |
1da177e4 LT |
3209 | { |
3210 | } | |
dd41f596 IM |
3211 | |
3212 | /* Avoid "used but not defined" warning on UP */ | |
3213 | static int balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
3214 | unsigned long max_nr_move, unsigned long max_load_move, | |
3215 | struct sched_domain *sd, enum cpu_idle_type idle, | |
3216 | int *all_pinned, unsigned long *load_moved, | |
a4ac01c3 | 3217 | int *this_best_prio, struct rq_iterator *iterator) |
dd41f596 IM |
3218 | { |
3219 | *load_moved = 0; | |
3220 | ||
3221 | return 0; | |
3222 | } | |
3223 | ||
1da177e4 LT |
3224 | #endif |
3225 | ||
1da177e4 LT |
3226 | DEFINE_PER_CPU(struct kernel_stat, kstat); |
3227 | ||
3228 | EXPORT_PER_CPU_SYMBOL(kstat); | |
3229 | ||
3230 | /* | |
41b86e9c IM |
3231 | * Return p->sum_exec_runtime plus any more ns on the sched_clock |
3232 | * that have not yet been banked in case the task is currently running. | |
1da177e4 | 3233 | */ |
41b86e9c | 3234 | unsigned long long task_sched_runtime(struct task_struct *p) |
1da177e4 | 3235 | { |
1da177e4 | 3236 | unsigned long flags; |
41b86e9c IM |
3237 | u64 ns, delta_exec; |
3238 | struct rq *rq; | |
48f24c4d | 3239 | |
41b86e9c IM |
3240 | rq = task_rq_lock(p, &flags); |
3241 | ns = p->se.sum_exec_runtime; | |
3242 | if (rq->curr == p) { | |
a8e504d2 IM |
3243 | update_rq_clock(rq); |
3244 | delta_exec = rq->clock - p->se.exec_start; | |
41b86e9c IM |
3245 | if ((s64)delta_exec > 0) |
3246 | ns += delta_exec; | |
3247 | } | |
3248 | task_rq_unlock(rq, &flags); | |
48f24c4d | 3249 | |
1da177e4 LT |
3250 | return ns; |
3251 | } | |
3252 | ||
1da177e4 LT |
3253 | /* |
3254 | * Account user cpu time to a process. | |
3255 | * @p: the process that the cpu time gets accounted to | |
3256 | * @hardirq_offset: the offset to subtract from hardirq_count() | |
3257 | * @cputime: the cpu time spent in user space since the last update | |
3258 | */ | |
3259 | void account_user_time(struct task_struct *p, cputime_t cputime) | |
3260 | { | |
3261 | struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; | |
3262 | cputime64_t tmp; | |
3263 | ||
3264 | p->utime = cputime_add(p->utime, cputime); | |
3265 | ||
3266 | /* Add user time to cpustat. */ | |
3267 | tmp = cputime_to_cputime64(cputime); | |
3268 | if (TASK_NICE(p) > 0) | |
3269 | cpustat->nice = cputime64_add(cpustat->nice, tmp); | |
3270 | else | |
3271 | cpustat->user = cputime64_add(cpustat->user, tmp); | |
3272 | } | |
3273 | ||
3274 | /* | |
3275 | * Account system cpu time to a process. | |
3276 | * @p: the process that the cpu time gets accounted to | |
3277 | * @hardirq_offset: the offset to subtract from hardirq_count() | |
3278 | * @cputime: the cpu time spent in kernel space since the last update | |
3279 | */ | |
3280 | void account_system_time(struct task_struct *p, int hardirq_offset, | |
3281 | cputime_t cputime) | |
3282 | { | |
3283 | struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; | |
70b97a7f | 3284 | struct rq *rq = this_rq(); |
1da177e4 LT |
3285 | cputime64_t tmp; |
3286 | ||
3287 | p->stime = cputime_add(p->stime, cputime); | |
3288 | ||
3289 | /* Add system time to cpustat. */ | |
3290 | tmp = cputime_to_cputime64(cputime); | |
3291 | if (hardirq_count() - hardirq_offset) | |
3292 | cpustat->irq = cputime64_add(cpustat->irq, tmp); | |
3293 | else if (softirq_count()) | |
3294 | cpustat->softirq = cputime64_add(cpustat->softirq, tmp); | |
3295 | else if (p != rq->idle) | |
3296 | cpustat->system = cputime64_add(cpustat->system, tmp); | |
3297 | else if (atomic_read(&rq->nr_iowait) > 0) | |
3298 | cpustat->iowait = cputime64_add(cpustat->iowait, tmp); | |
3299 | else | |
3300 | cpustat->idle = cputime64_add(cpustat->idle, tmp); | |
3301 | /* Account for system time used */ | |
3302 | acct_update_integrals(p); | |
1da177e4 LT |
3303 | } |
3304 | ||
3305 | /* | |
3306 | * Account for involuntary wait time. | |
3307 | * @p: the process from which the cpu time has been stolen | |
3308 | * @steal: the cpu time spent in involuntary wait | |
3309 | */ | |
3310 | void account_steal_time(struct task_struct *p, cputime_t steal) | |
3311 | { | |
3312 | struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; | |
3313 | cputime64_t tmp = cputime_to_cputime64(steal); | |
70b97a7f | 3314 | struct rq *rq = this_rq(); |
1da177e4 LT |
3315 | |
3316 | if (p == rq->idle) { | |
3317 | p->stime = cputime_add(p->stime, steal); | |
3318 | if (atomic_read(&rq->nr_iowait) > 0) | |
3319 | cpustat->iowait = cputime64_add(cpustat->iowait, tmp); | |
3320 | else | |
3321 | cpustat->idle = cputime64_add(cpustat->idle, tmp); | |
3322 | } else | |
3323 | cpustat->steal = cputime64_add(cpustat->steal, tmp); | |
3324 | } | |
3325 | ||
7835b98b CL |
3326 | /* |
3327 | * This function gets called by the timer code, with HZ frequency. | |
3328 | * We call it with interrupts disabled. | |
3329 | * | |
3330 | * It also gets called by the fork code, when changing the parent's | |
3331 | * timeslices. | |
3332 | */ | |
3333 | void scheduler_tick(void) | |
3334 | { | |
7835b98b CL |
3335 | int cpu = smp_processor_id(); |
3336 | struct rq *rq = cpu_rq(cpu); | |
dd41f596 | 3337 | struct task_struct *curr = rq->curr; |
529c7726 | 3338 | u64 next_tick = rq->tick_timestamp + TICK_NSEC; |
dd41f596 IM |
3339 | |
3340 | spin_lock(&rq->lock); | |
546fe3c9 | 3341 | __update_rq_clock(rq); |
529c7726 IM |
3342 | /* |
3343 | * Let rq->clock advance by at least TICK_NSEC: | |
3344 | */ | |
3345 | if (unlikely(rq->clock < next_tick)) | |
3346 | rq->clock = next_tick; | |
3347 | rq->tick_timestamp = rq->clock; | |
f1a438d8 | 3348 | update_cpu_load(rq); |
dd41f596 IM |
3349 | if (curr != rq->idle) /* FIXME: needed? */ |
3350 | curr->sched_class->task_tick(rq, curr); | |
dd41f596 | 3351 | spin_unlock(&rq->lock); |
7835b98b | 3352 | |
e418e1c2 | 3353 | #ifdef CONFIG_SMP |
dd41f596 IM |
3354 | rq->idle_at_tick = idle_cpu(cpu); |
3355 | trigger_load_balance(rq, cpu); | |
e418e1c2 | 3356 | #endif |
1da177e4 LT |
3357 | } |
3358 | ||
1da177e4 LT |
3359 | #if defined(CONFIG_PREEMPT) && defined(CONFIG_DEBUG_PREEMPT) |
3360 | ||
3361 | void fastcall add_preempt_count(int val) | |
3362 | { | |
3363 | /* | |
3364 | * Underflow? | |
3365 | */ | |
9a11b49a IM |
3366 | if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0))) |
3367 | return; | |
1da177e4 LT |
3368 | preempt_count() += val; |
3369 | /* | |
3370 | * Spinlock count overflowing soon? | |
3371 | */ | |
33859f7f MOS |
3372 | DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >= |
3373 | PREEMPT_MASK - 10); | |
1da177e4 LT |
3374 | } |
3375 | EXPORT_SYMBOL(add_preempt_count); | |
3376 | ||
3377 | void fastcall sub_preempt_count(int val) | |
3378 | { | |
3379 | /* | |
3380 | * Underflow? | |
3381 | */ | |
9a11b49a IM |
3382 | if (DEBUG_LOCKS_WARN_ON(val > preempt_count())) |
3383 | return; | |
1da177e4 LT |
3384 | /* |
3385 | * Is the spinlock portion underflowing? | |
3386 | */ | |
9a11b49a IM |
3387 | if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) && |
3388 | !(preempt_count() & PREEMPT_MASK))) | |
3389 | return; | |
3390 | ||
1da177e4 LT |
3391 | preempt_count() -= val; |
3392 | } | |
3393 | EXPORT_SYMBOL(sub_preempt_count); | |
3394 | ||
3395 | #endif | |
3396 | ||
3397 | /* | |
dd41f596 | 3398 | * Print scheduling while atomic bug: |
1da177e4 | 3399 | */ |
dd41f596 | 3400 | static noinline void __schedule_bug(struct task_struct *prev) |
1da177e4 | 3401 | { |
dd41f596 IM |
3402 | printk(KERN_ERR "BUG: scheduling while atomic: %s/0x%08x/%d\n", |
3403 | prev->comm, preempt_count(), prev->pid); | |
3404 | debug_show_held_locks(prev); | |
3405 | if (irqs_disabled()) | |
3406 | print_irqtrace_events(prev); | |
3407 | dump_stack(); | |
3408 | } | |
1da177e4 | 3409 | |
dd41f596 IM |
3410 | /* |
3411 | * Various schedule()-time debugging checks and statistics: | |
3412 | */ | |
3413 | static inline void schedule_debug(struct task_struct *prev) | |
3414 | { | |
1da177e4 LT |
3415 | /* |
3416 | * Test if we are atomic. Since do_exit() needs to call into | |
3417 | * schedule() atomically, we ignore that path for now. | |
3418 | * Otherwise, whine if we are scheduling when we should not be. | |
3419 | */ | |
dd41f596 IM |
3420 | if (unlikely(in_atomic_preempt_off()) && unlikely(!prev->exit_state)) |
3421 | __schedule_bug(prev); | |
3422 | ||
1da177e4 LT |
3423 | profile_hit(SCHED_PROFILING, __builtin_return_address(0)); |
3424 | ||
dd41f596 IM |
3425 | schedstat_inc(this_rq(), sched_cnt); |
3426 | } | |
3427 | ||
3428 | /* | |
3429 | * Pick up the highest-prio task: | |
3430 | */ | |
3431 | static inline struct task_struct * | |
ff95f3df | 3432 | pick_next_task(struct rq *rq, struct task_struct *prev) |
dd41f596 IM |
3433 | { |
3434 | struct sched_class *class; | |
3435 | struct task_struct *p; | |
1da177e4 LT |
3436 | |
3437 | /* | |
dd41f596 IM |
3438 | * Optimization: we know that if all tasks are in |
3439 | * the fair class we can call that function directly: | |
1da177e4 | 3440 | */ |
dd41f596 | 3441 | if (likely(rq->nr_running == rq->cfs.nr_running)) { |
fb8d4724 | 3442 | p = fair_sched_class.pick_next_task(rq); |
dd41f596 IM |
3443 | if (likely(p)) |
3444 | return p; | |
1da177e4 LT |
3445 | } |
3446 | ||
dd41f596 IM |
3447 | class = sched_class_highest; |
3448 | for ( ; ; ) { | |
fb8d4724 | 3449 | p = class->pick_next_task(rq); |
dd41f596 IM |
3450 | if (p) |
3451 | return p; | |
3452 | /* | |
3453 | * Will never be NULL as the idle class always | |
3454 | * returns a non-NULL p: | |
3455 | */ | |
3456 | class = class->next; | |
3457 | } | |
3458 | } | |
1da177e4 | 3459 | |
dd41f596 IM |
3460 | /* |
3461 | * schedule() is the main scheduler function. | |
3462 | */ | |
3463 | asmlinkage void __sched schedule(void) | |
3464 | { | |
3465 | struct task_struct *prev, *next; | |
3466 | long *switch_count; | |
3467 | struct rq *rq; | |
dd41f596 IM |
3468 | int cpu; |
3469 | ||
3470 | need_resched: | |
3471 | preempt_disable(); | |
3472 | cpu = smp_processor_id(); | |
3473 | rq = cpu_rq(cpu); | |
3474 | rcu_qsctr_inc(cpu); | |
3475 | prev = rq->curr; | |
3476 | switch_count = &prev->nivcsw; | |
3477 | ||
3478 | release_kernel_lock(prev); | |
3479 | need_resched_nonpreemptible: | |
3480 | ||
3481 | schedule_debug(prev); | |
1da177e4 LT |
3482 | |
3483 | spin_lock_irq(&rq->lock); | |
dd41f596 | 3484 | clear_tsk_need_resched(prev); |
c1b3da3e | 3485 | __update_rq_clock(rq); |
1da177e4 | 3486 | |
1da177e4 | 3487 | if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) { |
1da177e4 | 3488 | if (unlikely((prev->state & TASK_INTERRUPTIBLE) && |
dd41f596 | 3489 | unlikely(signal_pending(prev)))) { |
1da177e4 | 3490 | prev->state = TASK_RUNNING; |
dd41f596 | 3491 | } else { |
2e1cb74a | 3492 | deactivate_task(rq, prev, 1); |
1da177e4 | 3493 | } |
dd41f596 | 3494 | switch_count = &prev->nvcsw; |
1da177e4 LT |
3495 | } |
3496 | ||
dd41f596 | 3497 | if (unlikely(!rq->nr_running)) |
1da177e4 | 3498 | idle_balance(cpu, rq); |
1da177e4 | 3499 | |
31ee529c | 3500 | prev->sched_class->put_prev_task(rq, prev); |
ff95f3df | 3501 | next = pick_next_task(rq, prev); |
1da177e4 LT |
3502 | |
3503 | sched_info_switch(prev, next); | |
dd41f596 | 3504 | |
1da177e4 | 3505 | if (likely(prev != next)) { |
1da177e4 LT |
3506 | rq->nr_switches++; |
3507 | rq->curr = next; | |
3508 | ++*switch_count; | |
3509 | ||
dd41f596 | 3510 | context_switch(rq, prev, next); /* unlocks the rq */ |
1da177e4 LT |
3511 | } else |
3512 | spin_unlock_irq(&rq->lock); | |
3513 | ||
dd41f596 IM |
3514 | if (unlikely(reacquire_kernel_lock(current) < 0)) { |
3515 | cpu = smp_processor_id(); | |
3516 | rq = cpu_rq(cpu); | |
1da177e4 | 3517 | goto need_resched_nonpreemptible; |
dd41f596 | 3518 | } |
1da177e4 LT |
3519 | preempt_enable_no_resched(); |
3520 | if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) | |
3521 | goto need_resched; | |
3522 | } | |
1da177e4 LT |
3523 | EXPORT_SYMBOL(schedule); |
3524 | ||
3525 | #ifdef CONFIG_PREEMPT | |
3526 | /* | |
2ed6e34f | 3527 | * this is the entry point to schedule() from in-kernel preemption |
1da177e4 LT |
3528 | * off of preempt_enable. Kernel preemptions off return from interrupt |
3529 | * occur there and call schedule directly. | |
3530 | */ | |
3531 | asmlinkage void __sched preempt_schedule(void) | |
3532 | { | |
3533 | struct thread_info *ti = current_thread_info(); | |
3534 | #ifdef CONFIG_PREEMPT_BKL | |
3535 | struct task_struct *task = current; | |
3536 | int saved_lock_depth; | |
3537 | #endif | |
3538 | /* | |
3539 | * If there is a non-zero preempt_count or interrupts are disabled, | |
3540 | * we do not want to preempt the current task. Just return.. | |
3541 | */ | |
beed33a8 | 3542 | if (likely(ti->preempt_count || irqs_disabled())) |
1da177e4 LT |
3543 | return; |
3544 | ||
3545 | need_resched: | |
3546 | add_preempt_count(PREEMPT_ACTIVE); | |
3547 | /* | |
3548 | * We keep the big kernel semaphore locked, but we | |
3549 | * clear ->lock_depth so that schedule() doesnt | |
3550 | * auto-release the semaphore: | |
3551 | */ | |
3552 | #ifdef CONFIG_PREEMPT_BKL | |
3553 | saved_lock_depth = task->lock_depth; | |
3554 | task->lock_depth = -1; | |
3555 | #endif | |
3556 | schedule(); | |
3557 | #ifdef CONFIG_PREEMPT_BKL | |
3558 | task->lock_depth = saved_lock_depth; | |
3559 | #endif | |
3560 | sub_preempt_count(PREEMPT_ACTIVE); | |
3561 | ||
3562 | /* we could miss a preemption opportunity between schedule and now */ | |
3563 | barrier(); | |
3564 | if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) | |
3565 | goto need_resched; | |
3566 | } | |
1da177e4 LT |
3567 | EXPORT_SYMBOL(preempt_schedule); |
3568 | ||
3569 | /* | |
2ed6e34f | 3570 | * this is the entry point to schedule() from kernel preemption |
1da177e4 LT |
3571 | * off of irq context. |
3572 | * Note, that this is called and return with irqs disabled. This will | |
3573 | * protect us against recursive calling from irq. | |
3574 | */ | |
3575 | asmlinkage void __sched preempt_schedule_irq(void) | |
3576 | { | |
3577 | struct thread_info *ti = current_thread_info(); | |
3578 | #ifdef CONFIG_PREEMPT_BKL | |
3579 | struct task_struct *task = current; | |
3580 | int saved_lock_depth; | |
3581 | #endif | |
2ed6e34f | 3582 | /* Catch callers which need to be fixed */ |
1da177e4 LT |
3583 | BUG_ON(ti->preempt_count || !irqs_disabled()); |
3584 | ||
3585 | need_resched: | |
3586 | add_preempt_count(PREEMPT_ACTIVE); | |
3587 | /* | |
3588 | * We keep the big kernel semaphore locked, but we | |
3589 | * clear ->lock_depth so that schedule() doesnt | |
3590 | * auto-release the semaphore: | |
3591 | */ | |
3592 | #ifdef CONFIG_PREEMPT_BKL | |
3593 | saved_lock_depth = task->lock_depth; | |
3594 | task->lock_depth = -1; | |
3595 | #endif | |
3596 | local_irq_enable(); | |
3597 | schedule(); | |
3598 | local_irq_disable(); | |
3599 | #ifdef CONFIG_PREEMPT_BKL | |
3600 | task->lock_depth = saved_lock_depth; | |
3601 | #endif | |
3602 | sub_preempt_count(PREEMPT_ACTIVE); | |
3603 | ||
3604 | /* we could miss a preemption opportunity between schedule and now */ | |
3605 | barrier(); | |
3606 | if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) | |
3607 | goto need_resched; | |
3608 | } | |
3609 | ||
3610 | #endif /* CONFIG_PREEMPT */ | |
3611 | ||
95cdf3b7 IM |
3612 | int default_wake_function(wait_queue_t *curr, unsigned mode, int sync, |
3613 | void *key) | |
1da177e4 | 3614 | { |
48f24c4d | 3615 | return try_to_wake_up(curr->private, mode, sync); |
1da177e4 | 3616 | } |
1da177e4 LT |
3617 | EXPORT_SYMBOL(default_wake_function); |
3618 | ||
3619 | /* | |
3620 | * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just | |
3621 | * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve | |
3622 | * number) then we wake all the non-exclusive tasks and one exclusive task. | |
3623 | * | |
3624 | * There are circumstances in which we can try to wake a task which has already | |
3625 | * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns | |
3626 | * zero in this (rare) case, and we handle it by continuing to scan the queue. | |
3627 | */ | |
3628 | static void __wake_up_common(wait_queue_head_t *q, unsigned int mode, | |
3629 | int nr_exclusive, int sync, void *key) | |
3630 | { | |
3631 | struct list_head *tmp, *next; | |
3632 | ||
3633 | list_for_each_safe(tmp, next, &q->task_list) { | |
48f24c4d IM |
3634 | wait_queue_t *curr = list_entry(tmp, wait_queue_t, task_list); |
3635 | unsigned flags = curr->flags; | |
3636 | ||
1da177e4 | 3637 | if (curr->func(curr, mode, sync, key) && |
48f24c4d | 3638 | (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive) |
1da177e4 LT |
3639 | break; |
3640 | } | |
3641 | } | |
3642 | ||
3643 | /** | |
3644 | * __wake_up - wake up threads blocked on a waitqueue. | |
3645 | * @q: the waitqueue | |
3646 | * @mode: which threads | |
3647 | * @nr_exclusive: how many wake-one or wake-many threads to wake up | |
67be2dd1 | 3648 | * @key: is directly passed to the wakeup function |
1da177e4 LT |
3649 | */ |
3650 | void fastcall __wake_up(wait_queue_head_t *q, unsigned int mode, | |
95cdf3b7 | 3651 | int nr_exclusive, void *key) |
1da177e4 LT |
3652 | { |
3653 | unsigned long flags; | |
3654 | ||
3655 | spin_lock_irqsave(&q->lock, flags); | |
3656 | __wake_up_common(q, mode, nr_exclusive, 0, key); | |
3657 | spin_unlock_irqrestore(&q->lock, flags); | |
3658 | } | |
1da177e4 LT |
3659 | EXPORT_SYMBOL(__wake_up); |
3660 | ||
3661 | /* | |
3662 | * Same as __wake_up but called with the spinlock in wait_queue_head_t held. | |
3663 | */ | |
3664 | void fastcall __wake_up_locked(wait_queue_head_t *q, unsigned int mode) | |
3665 | { | |
3666 | __wake_up_common(q, mode, 1, 0, NULL); | |
3667 | } | |
3668 | ||
3669 | /** | |
67be2dd1 | 3670 | * __wake_up_sync - wake up threads blocked on a waitqueue. |
1da177e4 LT |
3671 | * @q: the waitqueue |
3672 | * @mode: which threads | |
3673 | * @nr_exclusive: how many wake-one or wake-many threads to wake up | |
3674 | * | |
3675 | * The sync wakeup differs that the waker knows that it will schedule | |
3676 | * away soon, so while the target thread will be woken up, it will not | |
3677 | * be migrated to another CPU - ie. the two threads are 'synchronized' | |
3678 | * with each other. This can prevent needless bouncing between CPUs. | |
3679 | * | |
3680 | * On UP it can prevent extra preemption. | |
3681 | */ | |
95cdf3b7 IM |
3682 | void fastcall |
3683 | __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive) | |
1da177e4 LT |
3684 | { |
3685 | unsigned long flags; | |
3686 | int sync = 1; | |
3687 | ||
3688 | if (unlikely(!q)) | |
3689 | return; | |
3690 | ||
3691 | if (unlikely(!nr_exclusive)) | |
3692 | sync = 0; | |
3693 | ||
3694 | spin_lock_irqsave(&q->lock, flags); | |
3695 | __wake_up_common(q, mode, nr_exclusive, sync, NULL); | |
3696 | spin_unlock_irqrestore(&q->lock, flags); | |
3697 | } | |
3698 | EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */ | |
3699 | ||
3700 | void fastcall complete(struct completion *x) | |
3701 | { | |
3702 | unsigned long flags; | |
3703 | ||
3704 | spin_lock_irqsave(&x->wait.lock, flags); | |
3705 | x->done++; | |
3706 | __wake_up_common(&x->wait, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, | |
3707 | 1, 0, NULL); | |
3708 | spin_unlock_irqrestore(&x->wait.lock, flags); | |
3709 | } | |
3710 | EXPORT_SYMBOL(complete); | |
3711 | ||
3712 | void fastcall complete_all(struct completion *x) | |
3713 | { | |
3714 | unsigned long flags; | |
3715 | ||
3716 | spin_lock_irqsave(&x->wait.lock, flags); | |
3717 | x->done += UINT_MAX/2; | |
3718 | __wake_up_common(&x->wait, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, | |
3719 | 0, 0, NULL); | |
3720 | spin_unlock_irqrestore(&x->wait.lock, flags); | |
3721 | } | |
3722 | EXPORT_SYMBOL(complete_all); | |
3723 | ||
3724 | void fastcall __sched wait_for_completion(struct completion *x) | |
3725 | { | |
3726 | might_sleep(); | |
48f24c4d | 3727 | |
1da177e4 LT |
3728 | spin_lock_irq(&x->wait.lock); |
3729 | if (!x->done) { | |
3730 | DECLARE_WAITQUEUE(wait, current); | |
3731 | ||
3732 | wait.flags |= WQ_FLAG_EXCLUSIVE; | |
3733 | __add_wait_queue_tail(&x->wait, &wait); | |
3734 | do { | |
3735 | __set_current_state(TASK_UNINTERRUPTIBLE); | |
3736 | spin_unlock_irq(&x->wait.lock); | |
3737 | schedule(); | |
3738 | spin_lock_irq(&x->wait.lock); | |
3739 | } while (!x->done); | |
3740 | __remove_wait_queue(&x->wait, &wait); | |
3741 | } | |
3742 | x->done--; | |
3743 | spin_unlock_irq(&x->wait.lock); | |
3744 | } | |
3745 | EXPORT_SYMBOL(wait_for_completion); | |
3746 | ||
3747 | unsigned long fastcall __sched | |
3748 | wait_for_completion_timeout(struct completion *x, unsigned long timeout) | |
3749 | { | |
3750 | might_sleep(); | |
3751 | ||
3752 | spin_lock_irq(&x->wait.lock); | |
3753 | if (!x->done) { | |
3754 | DECLARE_WAITQUEUE(wait, current); | |
3755 | ||
3756 | wait.flags |= WQ_FLAG_EXCLUSIVE; | |
3757 | __add_wait_queue_tail(&x->wait, &wait); | |
3758 | do { | |
3759 | __set_current_state(TASK_UNINTERRUPTIBLE); | |
3760 | spin_unlock_irq(&x->wait.lock); | |
3761 | timeout = schedule_timeout(timeout); | |
3762 | spin_lock_irq(&x->wait.lock); | |
3763 | if (!timeout) { | |
3764 | __remove_wait_queue(&x->wait, &wait); | |
3765 | goto out; | |
3766 | } | |
3767 | } while (!x->done); | |
3768 | __remove_wait_queue(&x->wait, &wait); | |
3769 | } | |
3770 | x->done--; | |
3771 | out: | |
3772 | spin_unlock_irq(&x->wait.lock); | |
3773 | return timeout; | |
3774 | } | |
3775 | EXPORT_SYMBOL(wait_for_completion_timeout); | |
3776 | ||
3777 | int fastcall __sched wait_for_completion_interruptible(struct completion *x) | |
3778 | { | |
3779 | int ret = 0; | |
3780 | ||
3781 | might_sleep(); | |
3782 | ||
3783 | spin_lock_irq(&x->wait.lock); | |
3784 | if (!x->done) { | |
3785 | DECLARE_WAITQUEUE(wait, current); | |
3786 | ||
3787 | wait.flags |= WQ_FLAG_EXCLUSIVE; | |
3788 | __add_wait_queue_tail(&x->wait, &wait); | |
3789 | do { | |
3790 | if (signal_pending(current)) { | |
3791 | ret = -ERESTARTSYS; | |
3792 | __remove_wait_queue(&x->wait, &wait); | |
3793 | goto out; | |
3794 | } | |
3795 | __set_current_state(TASK_INTERRUPTIBLE); | |
3796 | spin_unlock_irq(&x->wait.lock); | |
3797 | schedule(); | |
3798 | spin_lock_irq(&x->wait.lock); | |
3799 | } while (!x->done); | |
3800 | __remove_wait_queue(&x->wait, &wait); | |
3801 | } | |
3802 | x->done--; | |
3803 | out: | |
3804 | spin_unlock_irq(&x->wait.lock); | |
3805 | ||
3806 | return ret; | |
3807 | } | |
3808 | EXPORT_SYMBOL(wait_for_completion_interruptible); | |
3809 | ||
3810 | unsigned long fastcall __sched | |
3811 | wait_for_completion_interruptible_timeout(struct completion *x, | |
3812 | unsigned long timeout) | |
3813 | { | |
3814 | might_sleep(); | |
3815 | ||
3816 | spin_lock_irq(&x->wait.lock); | |
3817 | if (!x->done) { | |
3818 | DECLARE_WAITQUEUE(wait, current); | |
3819 | ||
3820 | wait.flags |= WQ_FLAG_EXCLUSIVE; | |
3821 | __add_wait_queue_tail(&x->wait, &wait); | |
3822 | do { | |
3823 | if (signal_pending(current)) { | |
3824 | timeout = -ERESTARTSYS; | |
3825 | __remove_wait_queue(&x->wait, &wait); | |
3826 | goto out; | |
3827 | } | |
3828 | __set_current_state(TASK_INTERRUPTIBLE); | |
3829 | spin_unlock_irq(&x->wait.lock); | |
3830 | timeout = schedule_timeout(timeout); | |
3831 | spin_lock_irq(&x->wait.lock); | |
3832 | if (!timeout) { | |
3833 | __remove_wait_queue(&x->wait, &wait); | |
3834 | goto out; | |
3835 | } | |
3836 | } while (!x->done); | |
3837 | __remove_wait_queue(&x->wait, &wait); | |
3838 | } | |
3839 | x->done--; | |
3840 | out: | |
3841 | spin_unlock_irq(&x->wait.lock); | |
3842 | return timeout; | |
3843 | } | |
3844 | EXPORT_SYMBOL(wait_for_completion_interruptible_timeout); | |
3845 | ||
0fec171c IM |
3846 | static inline void |
3847 | sleep_on_head(wait_queue_head_t *q, wait_queue_t *wait, unsigned long *flags) | |
3848 | { | |
3849 | spin_lock_irqsave(&q->lock, *flags); | |
3850 | __add_wait_queue(q, wait); | |
1da177e4 | 3851 | spin_unlock(&q->lock); |
0fec171c | 3852 | } |
1da177e4 | 3853 | |
0fec171c IM |
3854 | static inline void |
3855 | sleep_on_tail(wait_queue_head_t *q, wait_queue_t *wait, unsigned long *flags) | |
3856 | { | |
3857 | spin_lock_irq(&q->lock); | |
3858 | __remove_wait_queue(q, wait); | |
3859 | spin_unlock_irqrestore(&q->lock, *flags); | |
3860 | } | |
1da177e4 | 3861 | |
0fec171c | 3862 | void __sched interruptible_sleep_on(wait_queue_head_t *q) |
1da177e4 | 3863 | { |
0fec171c IM |
3864 | unsigned long flags; |
3865 | wait_queue_t wait; | |
3866 | ||
3867 | init_waitqueue_entry(&wait, current); | |
1da177e4 LT |
3868 | |
3869 | current->state = TASK_INTERRUPTIBLE; | |
3870 | ||
0fec171c | 3871 | sleep_on_head(q, &wait, &flags); |
1da177e4 | 3872 | schedule(); |
0fec171c | 3873 | sleep_on_tail(q, &wait, &flags); |
1da177e4 | 3874 | } |
1da177e4 LT |
3875 | EXPORT_SYMBOL(interruptible_sleep_on); |
3876 | ||
0fec171c | 3877 | long __sched |
95cdf3b7 | 3878 | interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout) |
1da177e4 | 3879 | { |
0fec171c IM |
3880 | unsigned long flags; |
3881 | wait_queue_t wait; | |
3882 | ||
3883 | init_waitqueue_entry(&wait, current); | |
1da177e4 LT |
3884 | |
3885 | current->state = TASK_INTERRUPTIBLE; | |
3886 | ||
0fec171c | 3887 | sleep_on_head(q, &wait, &flags); |
1da177e4 | 3888 | timeout = schedule_timeout(timeout); |
0fec171c | 3889 | sleep_on_tail(q, &wait, &flags); |
1da177e4 LT |
3890 | |
3891 | return timeout; | |
3892 | } | |
1da177e4 LT |
3893 | EXPORT_SYMBOL(interruptible_sleep_on_timeout); |
3894 | ||
0fec171c | 3895 | void __sched sleep_on(wait_queue_head_t *q) |
1da177e4 | 3896 | { |
0fec171c IM |
3897 | unsigned long flags; |
3898 | wait_queue_t wait; | |
3899 | ||
3900 | init_waitqueue_entry(&wait, current); | |
1da177e4 LT |
3901 | |
3902 | current->state = TASK_UNINTERRUPTIBLE; | |
3903 | ||
0fec171c | 3904 | sleep_on_head(q, &wait, &flags); |
1da177e4 | 3905 | schedule(); |
0fec171c | 3906 | sleep_on_tail(q, &wait, &flags); |
1da177e4 | 3907 | } |
1da177e4 LT |
3908 | EXPORT_SYMBOL(sleep_on); |
3909 | ||
0fec171c | 3910 | long __sched sleep_on_timeout(wait_queue_head_t *q, long timeout) |
1da177e4 | 3911 | { |
0fec171c IM |
3912 | unsigned long flags; |
3913 | wait_queue_t wait; | |
3914 | ||
3915 | init_waitqueue_entry(&wait, current); | |
1da177e4 LT |
3916 | |
3917 | current->state = TASK_UNINTERRUPTIBLE; | |
3918 | ||
0fec171c | 3919 | sleep_on_head(q, &wait, &flags); |
1da177e4 | 3920 | timeout = schedule_timeout(timeout); |
0fec171c | 3921 | sleep_on_tail(q, &wait, &flags); |
1da177e4 LT |
3922 | |
3923 | return timeout; | |
3924 | } | |
1da177e4 LT |
3925 | EXPORT_SYMBOL(sleep_on_timeout); |
3926 | ||
b29739f9 IM |
3927 | #ifdef CONFIG_RT_MUTEXES |
3928 | ||
3929 | /* | |
3930 | * rt_mutex_setprio - set the current priority of a task | |
3931 | * @p: task | |
3932 | * @prio: prio value (kernel-internal form) | |
3933 | * | |
3934 | * This function changes the 'effective' priority of a task. It does | |
3935 | * not touch ->normal_prio like __setscheduler(). | |
3936 | * | |
3937 | * Used by the rt_mutex code to implement priority inheritance logic. | |
3938 | */ | |
36c8b586 | 3939 | void rt_mutex_setprio(struct task_struct *p, int prio) |
b29739f9 IM |
3940 | { |
3941 | unsigned long flags; | |
dd41f596 | 3942 | int oldprio, on_rq; |
70b97a7f | 3943 | struct rq *rq; |
b29739f9 IM |
3944 | |
3945 | BUG_ON(prio < 0 || prio > MAX_PRIO); | |
3946 | ||
3947 | rq = task_rq_lock(p, &flags); | |
a8e504d2 | 3948 | update_rq_clock(rq); |
b29739f9 | 3949 | |
d5f9f942 | 3950 | oldprio = p->prio; |
dd41f596 IM |
3951 | on_rq = p->se.on_rq; |
3952 | if (on_rq) | |
69be72c1 | 3953 | dequeue_task(rq, p, 0); |
dd41f596 IM |
3954 | |
3955 | if (rt_prio(prio)) | |
3956 | p->sched_class = &rt_sched_class; | |
3957 | else | |
3958 | p->sched_class = &fair_sched_class; | |
3959 | ||
b29739f9 IM |
3960 | p->prio = prio; |
3961 | ||
dd41f596 | 3962 | if (on_rq) { |
8159f87e | 3963 | enqueue_task(rq, p, 0); |
b29739f9 IM |
3964 | /* |
3965 | * Reschedule if we are currently running on this runqueue and | |
d5f9f942 AM |
3966 | * our priority decreased, or if we are not currently running on |
3967 | * this runqueue and our priority is higher than the current's | |
b29739f9 | 3968 | */ |
d5f9f942 AM |
3969 | if (task_running(rq, p)) { |
3970 | if (p->prio > oldprio) | |
3971 | resched_task(rq->curr); | |
dd41f596 IM |
3972 | } else { |
3973 | check_preempt_curr(rq, p); | |
3974 | } | |
b29739f9 IM |
3975 | } |
3976 | task_rq_unlock(rq, &flags); | |
3977 | } | |
3978 | ||
3979 | #endif | |
3980 | ||
36c8b586 | 3981 | void set_user_nice(struct task_struct *p, long nice) |
1da177e4 | 3982 | { |
dd41f596 | 3983 | int old_prio, delta, on_rq; |
1da177e4 | 3984 | unsigned long flags; |
70b97a7f | 3985 | struct rq *rq; |
1da177e4 LT |
3986 | |
3987 | if (TASK_NICE(p) == nice || nice < -20 || nice > 19) | |
3988 | return; | |
3989 | /* | |
3990 | * We have to be careful, if called from sys_setpriority(), | |
3991 | * the task might be in the middle of scheduling on another CPU. | |
3992 | */ | |
3993 | rq = task_rq_lock(p, &flags); | |
a8e504d2 | 3994 | update_rq_clock(rq); |
1da177e4 LT |
3995 | /* |
3996 | * The RT priorities are set via sched_setscheduler(), but we still | |
3997 | * allow the 'normal' nice value to be set - but as expected | |
3998 | * it wont have any effect on scheduling until the task is | |
dd41f596 | 3999 | * SCHED_FIFO/SCHED_RR: |
1da177e4 | 4000 | */ |
e05606d3 | 4001 | if (task_has_rt_policy(p)) { |
1da177e4 LT |
4002 | p->static_prio = NICE_TO_PRIO(nice); |
4003 | goto out_unlock; | |
4004 | } | |
dd41f596 IM |
4005 | on_rq = p->se.on_rq; |
4006 | if (on_rq) { | |
69be72c1 | 4007 | dequeue_task(rq, p, 0); |
79b5dddf | 4008 | dec_load(rq, p); |
2dd73a4f | 4009 | } |
1da177e4 | 4010 | |
1da177e4 | 4011 | p->static_prio = NICE_TO_PRIO(nice); |
2dd73a4f | 4012 | set_load_weight(p); |
b29739f9 IM |
4013 | old_prio = p->prio; |
4014 | p->prio = effective_prio(p); | |
4015 | delta = p->prio - old_prio; | |
1da177e4 | 4016 | |
dd41f596 | 4017 | if (on_rq) { |
8159f87e | 4018 | enqueue_task(rq, p, 0); |
29b4b623 | 4019 | inc_load(rq, p); |
1da177e4 | 4020 | /* |
d5f9f942 AM |
4021 | * If the task increased its priority or is running and |
4022 | * lowered its priority, then reschedule its CPU: | |
1da177e4 | 4023 | */ |
d5f9f942 | 4024 | if (delta < 0 || (delta > 0 && task_running(rq, p))) |
1da177e4 LT |
4025 | resched_task(rq->curr); |
4026 | } | |
4027 | out_unlock: | |
4028 | task_rq_unlock(rq, &flags); | |
4029 | } | |
1da177e4 LT |
4030 | EXPORT_SYMBOL(set_user_nice); |
4031 | ||
e43379f1 MM |
4032 | /* |
4033 | * can_nice - check if a task can reduce its nice value | |
4034 | * @p: task | |
4035 | * @nice: nice value | |
4036 | */ | |
36c8b586 | 4037 | int can_nice(const struct task_struct *p, const int nice) |
e43379f1 | 4038 | { |
024f4747 MM |
4039 | /* convert nice value [19,-20] to rlimit style value [1,40] */ |
4040 | int nice_rlim = 20 - nice; | |
48f24c4d | 4041 | |
e43379f1 MM |
4042 | return (nice_rlim <= p->signal->rlim[RLIMIT_NICE].rlim_cur || |
4043 | capable(CAP_SYS_NICE)); | |
4044 | } | |
4045 | ||
1da177e4 LT |
4046 | #ifdef __ARCH_WANT_SYS_NICE |
4047 | ||
4048 | /* | |
4049 | * sys_nice - change the priority of the current process. | |
4050 | * @increment: priority increment | |
4051 | * | |
4052 | * sys_setpriority is a more generic, but much slower function that | |
4053 | * does similar things. | |
4054 | */ | |
4055 | asmlinkage long sys_nice(int increment) | |
4056 | { | |
48f24c4d | 4057 | long nice, retval; |
1da177e4 LT |
4058 | |
4059 | /* | |
4060 | * Setpriority might change our priority at the same moment. | |
4061 | * We don't have to worry. Conceptually one call occurs first | |
4062 | * and we have a single winner. | |
4063 | */ | |
e43379f1 MM |
4064 | if (increment < -40) |
4065 | increment = -40; | |
1da177e4 LT |
4066 | if (increment > 40) |
4067 | increment = 40; | |
4068 | ||
4069 | nice = PRIO_TO_NICE(current->static_prio) + increment; | |
4070 | if (nice < -20) | |
4071 | nice = -20; | |
4072 | if (nice > 19) | |
4073 | nice = 19; | |
4074 | ||
e43379f1 MM |
4075 | if (increment < 0 && !can_nice(current, nice)) |
4076 | return -EPERM; | |
4077 | ||
1da177e4 LT |
4078 | retval = security_task_setnice(current, nice); |
4079 | if (retval) | |
4080 | return retval; | |
4081 | ||
4082 | set_user_nice(current, nice); | |
4083 | return 0; | |
4084 | } | |
4085 | ||
4086 | #endif | |
4087 | ||
4088 | /** | |
4089 | * task_prio - return the priority value of a given task. | |
4090 | * @p: the task in question. | |
4091 | * | |
4092 | * This is the priority value as seen by users in /proc. | |
4093 | * RT tasks are offset by -200. Normal tasks are centered | |
4094 | * around 0, value goes from -16 to +15. | |
4095 | */ | |
36c8b586 | 4096 | int task_prio(const struct task_struct *p) |
1da177e4 LT |
4097 | { |
4098 | return p->prio - MAX_RT_PRIO; | |
4099 | } | |
4100 | ||
4101 | /** | |
4102 | * task_nice - return the nice value of a given task. | |
4103 | * @p: the task in question. | |
4104 | */ | |
36c8b586 | 4105 | int task_nice(const struct task_struct *p) |
1da177e4 LT |
4106 | { |
4107 | return TASK_NICE(p); | |
4108 | } | |
1da177e4 | 4109 | EXPORT_SYMBOL_GPL(task_nice); |
1da177e4 LT |
4110 | |
4111 | /** | |
4112 | * idle_cpu - is a given cpu idle currently? | |
4113 | * @cpu: the processor in question. | |
4114 | */ | |
4115 | int idle_cpu(int cpu) | |
4116 | { | |
4117 | return cpu_curr(cpu) == cpu_rq(cpu)->idle; | |
4118 | } | |
4119 | ||
1da177e4 LT |
4120 | /** |
4121 | * idle_task - return the idle task for a given cpu. | |
4122 | * @cpu: the processor in question. | |
4123 | */ | |
36c8b586 | 4124 | struct task_struct *idle_task(int cpu) |
1da177e4 LT |
4125 | { |
4126 | return cpu_rq(cpu)->idle; | |
4127 | } | |
4128 | ||
4129 | /** | |
4130 | * find_process_by_pid - find a process with a matching PID value. | |
4131 | * @pid: the pid in question. | |
4132 | */ | |
36c8b586 | 4133 | static inline struct task_struct *find_process_by_pid(pid_t pid) |
1da177e4 LT |
4134 | { |
4135 | return pid ? find_task_by_pid(pid) : current; | |
4136 | } | |
4137 | ||
4138 | /* Actually do priority change: must hold rq lock. */ | |
dd41f596 IM |
4139 | static void |
4140 | __setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio) | |
1da177e4 | 4141 | { |
dd41f596 | 4142 | BUG_ON(p->se.on_rq); |
48f24c4d | 4143 | |
1da177e4 | 4144 | p->policy = policy; |
dd41f596 IM |
4145 | switch (p->policy) { |
4146 | case SCHED_NORMAL: | |
4147 | case SCHED_BATCH: | |
4148 | case SCHED_IDLE: | |
4149 | p->sched_class = &fair_sched_class; | |
4150 | break; | |
4151 | case SCHED_FIFO: | |
4152 | case SCHED_RR: | |
4153 | p->sched_class = &rt_sched_class; | |
4154 | break; | |
4155 | } | |
4156 | ||
1da177e4 | 4157 | p->rt_priority = prio; |
b29739f9 IM |
4158 | p->normal_prio = normal_prio(p); |
4159 | /* we are holding p->pi_lock already */ | |
4160 | p->prio = rt_mutex_getprio(p); | |
2dd73a4f | 4161 | set_load_weight(p); |
1da177e4 LT |
4162 | } |
4163 | ||
4164 | /** | |
72fd4a35 | 4165 | * sched_setscheduler - change the scheduling policy and/or RT priority of a thread. |
1da177e4 LT |
4166 | * @p: the task in question. |
4167 | * @policy: new policy. | |
4168 | * @param: structure containing the new RT priority. | |
5fe1d75f | 4169 | * |
72fd4a35 | 4170 | * NOTE that the task may be already dead. |
1da177e4 | 4171 | */ |
95cdf3b7 IM |
4172 | int sched_setscheduler(struct task_struct *p, int policy, |
4173 | struct sched_param *param) | |
1da177e4 | 4174 | { |
dd41f596 | 4175 | int retval, oldprio, oldpolicy = -1, on_rq; |
1da177e4 | 4176 | unsigned long flags; |
70b97a7f | 4177 | struct rq *rq; |
1da177e4 | 4178 | |
66e5393a SR |
4179 | /* may grab non-irq protected spin_locks */ |
4180 | BUG_ON(in_interrupt()); | |
1da177e4 LT |
4181 | recheck: |
4182 | /* double check policy once rq lock held */ | |
4183 | if (policy < 0) | |
4184 | policy = oldpolicy = p->policy; | |
4185 | else if (policy != SCHED_FIFO && policy != SCHED_RR && | |
dd41f596 IM |
4186 | policy != SCHED_NORMAL && policy != SCHED_BATCH && |
4187 | policy != SCHED_IDLE) | |
b0a9499c | 4188 | return -EINVAL; |
1da177e4 LT |
4189 | /* |
4190 | * Valid priorities for SCHED_FIFO and SCHED_RR are | |
dd41f596 IM |
4191 | * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL, |
4192 | * SCHED_BATCH and SCHED_IDLE is 0. | |
1da177e4 LT |
4193 | */ |
4194 | if (param->sched_priority < 0 || | |
95cdf3b7 | 4195 | (p->mm && param->sched_priority > MAX_USER_RT_PRIO-1) || |
d46523ea | 4196 | (!p->mm && param->sched_priority > MAX_RT_PRIO-1)) |
1da177e4 | 4197 | return -EINVAL; |
e05606d3 | 4198 | if (rt_policy(policy) != (param->sched_priority != 0)) |
1da177e4 LT |
4199 | return -EINVAL; |
4200 | ||
37e4ab3f OC |
4201 | /* |
4202 | * Allow unprivileged RT tasks to decrease priority: | |
4203 | */ | |
4204 | if (!capable(CAP_SYS_NICE)) { | |
e05606d3 | 4205 | if (rt_policy(policy)) { |
8dc3e909 | 4206 | unsigned long rlim_rtprio; |
8dc3e909 ON |
4207 | |
4208 | if (!lock_task_sighand(p, &flags)) | |
4209 | return -ESRCH; | |
4210 | rlim_rtprio = p->signal->rlim[RLIMIT_RTPRIO].rlim_cur; | |
4211 | unlock_task_sighand(p, &flags); | |
4212 | ||
4213 | /* can't set/change the rt policy */ | |
4214 | if (policy != p->policy && !rlim_rtprio) | |
4215 | return -EPERM; | |
4216 | ||
4217 | /* can't increase priority */ | |
4218 | if (param->sched_priority > p->rt_priority && | |
4219 | param->sched_priority > rlim_rtprio) | |
4220 | return -EPERM; | |
4221 | } | |
dd41f596 IM |
4222 | /* |
4223 | * Like positive nice levels, dont allow tasks to | |
4224 | * move out of SCHED_IDLE either: | |
4225 | */ | |
4226 | if (p->policy == SCHED_IDLE && policy != SCHED_IDLE) | |
4227 | return -EPERM; | |
5fe1d75f | 4228 | |
37e4ab3f OC |
4229 | /* can't change other user's priorities */ |
4230 | if ((current->euid != p->euid) && | |
4231 | (current->euid != p->uid)) | |
4232 | return -EPERM; | |
4233 | } | |
1da177e4 LT |
4234 | |
4235 | retval = security_task_setscheduler(p, policy, param); | |
4236 | if (retval) | |
4237 | return retval; | |
b29739f9 IM |
4238 | /* |
4239 | * make sure no PI-waiters arrive (or leave) while we are | |
4240 | * changing the priority of the task: | |
4241 | */ | |
4242 | spin_lock_irqsave(&p->pi_lock, flags); | |
1da177e4 LT |
4243 | /* |
4244 | * To be able to change p->policy safely, the apropriate | |
4245 | * runqueue lock must be held. | |
4246 | */ | |
b29739f9 | 4247 | rq = __task_rq_lock(p); |
1da177e4 LT |
4248 | /* recheck policy now with rq lock held */ |
4249 | if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) { | |
4250 | policy = oldpolicy = -1; | |
b29739f9 IM |
4251 | __task_rq_unlock(rq); |
4252 | spin_unlock_irqrestore(&p->pi_lock, flags); | |
1da177e4 LT |
4253 | goto recheck; |
4254 | } | |
2daa3577 | 4255 | update_rq_clock(rq); |
dd41f596 | 4256 | on_rq = p->se.on_rq; |
2daa3577 | 4257 | if (on_rq) |
2e1cb74a | 4258 | deactivate_task(rq, p, 0); |
1da177e4 | 4259 | oldprio = p->prio; |
dd41f596 IM |
4260 | __setscheduler(rq, p, policy, param->sched_priority); |
4261 | if (on_rq) { | |
4262 | activate_task(rq, p, 0); | |
1da177e4 LT |
4263 | /* |
4264 | * Reschedule if we are currently running on this runqueue and | |
d5f9f942 AM |
4265 | * our priority decreased, or if we are not currently running on |
4266 | * this runqueue and our priority is higher than the current's | |
1da177e4 | 4267 | */ |
d5f9f942 AM |
4268 | if (task_running(rq, p)) { |
4269 | if (p->prio > oldprio) | |
4270 | resched_task(rq->curr); | |
dd41f596 IM |
4271 | } else { |
4272 | check_preempt_curr(rq, p); | |
4273 | } | |
1da177e4 | 4274 | } |
b29739f9 IM |
4275 | __task_rq_unlock(rq); |
4276 | spin_unlock_irqrestore(&p->pi_lock, flags); | |
4277 | ||
95e02ca9 TG |
4278 | rt_mutex_adjust_pi(p); |
4279 | ||
1da177e4 LT |
4280 | return 0; |
4281 | } | |
4282 | EXPORT_SYMBOL_GPL(sched_setscheduler); | |
4283 | ||
95cdf3b7 IM |
4284 | static int |
4285 | do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param) | |
1da177e4 | 4286 | { |
1da177e4 LT |
4287 | struct sched_param lparam; |
4288 | struct task_struct *p; | |
36c8b586 | 4289 | int retval; |
1da177e4 LT |
4290 | |
4291 | if (!param || pid < 0) | |
4292 | return -EINVAL; | |
4293 | if (copy_from_user(&lparam, param, sizeof(struct sched_param))) | |
4294 | return -EFAULT; | |
5fe1d75f ON |
4295 | |
4296 | rcu_read_lock(); | |
4297 | retval = -ESRCH; | |
1da177e4 | 4298 | p = find_process_by_pid(pid); |
5fe1d75f ON |
4299 | if (p != NULL) |
4300 | retval = sched_setscheduler(p, policy, &lparam); | |
4301 | rcu_read_unlock(); | |
36c8b586 | 4302 | |
1da177e4 LT |
4303 | return retval; |
4304 | } | |
4305 | ||
4306 | /** | |
4307 | * sys_sched_setscheduler - set/change the scheduler policy and RT priority | |
4308 | * @pid: the pid in question. | |
4309 | * @policy: new policy. | |
4310 | * @param: structure containing the new RT priority. | |
4311 | */ | |
4312 | asmlinkage long sys_sched_setscheduler(pid_t pid, int policy, | |
4313 | struct sched_param __user *param) | |
4314 | { | |
c21761f1 JB |
4315 | /* negative values for policy are not valid */ |
4316 | if (policy < 0) | |
4317 | return -EINVAL; | |
4318 | ||
1da177e4 LT |
4319 | return do_sched_setscheduler(pid, policy, param); |
4320 | } | |
4321 | ||
4322 | /** | |
4323 | * sys_sched_setparam - set/change the RT priority of a thread | |
4324 | * @pid: the pid in question. | |
4325 | * @param: structure containing the new RT priority. | |
4326 | */ | |
4327 | asmlinkage long sys_sched_setparam(pid_t pid, struct sched_param __user *param) | |
4328 | { | |
4329 | return do_sched_setscheduler(pid, -1, param); | |
4330 | } | |
4331 | ||
4332 | /** | |
4333 | * sys_sched_getscheduler - get the policy (scheduling class) of a thread | |
4334 | * @pid: the pid in question. | |
4335 | */ | |
4336 | asmlinkage long sys_sched_getscheduler(pid_t pid) | |
4337 | { | |
36c8b586 | 4338 | struct task_struct *p; |
1da177e4 | 4339 | int retval = -EINVAL; |
1da177e4 LT |
4340 | |
4341 | if (pid < 0) | |
4342 | goto out_nounlock; | |
4343 | ||
4344 | retval = -ESRCH; | |
4345 | read_lock(&tasklist_lock); | |
4346 | p = find_process_by_pid(pid); | |
4347 | if (p) { | |
4348 | retval = security_task_getscheduler(p); | |
4349 | if (!retval) | |
4350 | retval = p->policy; | |
4351 | } | |
4352 | read_unlock(&tasklist_lock); | |
4353 | ||
4354 | out_nounlock: | |
4355 | return retval; | |
4356 | } | |
4357 | ||
4358 | /** | |
4359 | * sys_sched_getscheduler - get the RT priority of a thread | |
4360 | * @pid: the pid in question. | |
4361 | * @param: structure containing the RT priority. | |
4362 | */ | |
4363 | asmlinkage long sys_sched_getparam(pid_t pid, struct sched_param __user *param) | |
4364 | { | |
4365 | struct sched_param lp; | |
36c8b586 | 4366 | struct task_struct *p; |
1da177e4 | 4367 | int retval = -EINVAL; |
1da177e4 LT |
4368 | |
4369 | if (!param || pid < 0) | |
4370 | goto out_nounlock; | |
4371 | ||
4372 | read_lock(&tasklist_lock); | |
4373 | p = find_process_by_pid(pid); | |
4374 | retval = -ESRCH; | |
4375 | if (!p) | |
4376 | goto out_unlock; | |
4377 | ||
4378 | retval = security_task_getscheduler(p); | |
4379 | if (retval) | |
4380 | goto out_unlock; | |
4381 | ||
4382 | lp.sched_priority = p->rt_priority; | |
4383 | read_unlock(&tasklist_lock); | |
4384 | ||
4385 | /* | |
4386 | * This one might sleep, we cannot do it with a spinlock held ... | |
4387 | */ | |
4388 | retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0; | |
4389 | ||
4390 | out_nounlock: | |
4391 | return retval; | |
4392 | ||
4393 | out_unlock: | |
4394 | read_unlock(&tasklist_lock); | |
4395 | return retval; | |
4396 | } | |
4397 | ||
4398 | long sched_setaffinity(pid_t pid, cpumask_t new_mask) | |
4399 | { | |
1da177e4 | 4400 | cpumask_t cpus_allowed; |
36c8b586 IM |
4401 | struct task_struct *p; |
4402 | int retval; | |
1da177e4 | 4403 | |
5be9361c | 4404 | mutex_lock(&sched_hotcpu_mutex); |
1da177e4 LT |
4405 | read_lock(&tasklist_lock); |
4406 | ||
4407 | p = find_process_by_pid(pid); | |
4408 | if (!p) { | |
4409 | read_unlock(&tasklist_lock); | |
5be9361c | 4410 | mutex_unlock(&sched_hotcpu_mutex); |
1da177e4 LT |
4411 | return -ESRCH; |
4412 | } | |
4413 | ||
4414 | /* | |
4415 | * It is not safe to call set_cpus_allowed with the | |
4416 | * tasklist_lock held. We will bump the task_struct's | |
4417 | * usage count and then drop tasklist_lock. | |
4418 | */ | |
4419 | get_task_struct(p); | |
4420 | read_unlock(&tasklist_lock); | |
4421 | ||
4422 | retval = -EPERM; | |
4423 | if ((current->euid != p->euid) && (current->euid != p->uid) && | |
4424 | !capable(CAP_SYS_NICE)) | |
4425 | goto out_unlock; | |
4426 | ||
e7834f8f DQ |
4427 | retval = security_task_setscheduler(p, 0, NULL); |
4428 | if (retval) | |
4429 | goto out_unlock; | |
4430 | ||
1da177e4 LT |
4431 | cpus_allowed = cpuset_cpus_allowed(p); |
4432 | cpus_and(new_mask, new_mask, cpus_allowed); | |
4433 | retval = set_cpus_allowed(p, new_mask); | |
4434 | ||
4435 | out_unlock: | |
4436 | put_task_struct(p); | |
5be9361c | 4437 | mutex_unlock(&sched_hotcpu_mutex); |
1da177e4 LT |
4438 | return retval; |
4439 | } | |
4440 | ||
4441 | static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len, | |
4442 | cpumask_t *new_mask) | |
4443 | { | |
4444 | if (len < sizeof(cpumask_t)) { | |
4445 | memset(new_mask, 0, sizeof(cpumask_t)); | |
4446 | } else if (len > sizeof(cpumask_t)) { | |
4447 | len = sizeof(cpumask_t); | |
4448 | } | |
4449 | return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0; | |
4450 | } | |
4451 | ||
4452 | /** | |
4453 | * sys_sched_setaffinity - set the cpu affinity of a process | |
4454 | * @pid: pid of the process | |
4455 | * @len: length in bytes of the bitmask pointed to by user_mask_ptr | |
4456 | * @user_mask_ptr: user-space pointer to the new cpu mask | |
4457 | */ | |
4458 | asmlinkage long sys_sched_setaffinity(pid_t pid, unsigned int len, | |
4459 | unsigned long __user *user_mask_ptr) | |
4460 | { | |
4461 | cpumask_t new_mask; | |
4462 | int retval; | |
4463 | ||
4464 | retval = get_user_cpu_mask(user_mask_ptr, len, &new_mask); | |
4465 | if (retval) | |
4466 | return retval; | |
4467 | ||
4468 | return sched_setaffinity(pid, new_mask); | |
4469 | } | |
4470 | ||
4471 | /* | |
4472 | * Represents all cpu's present in the system | |
4473 | * In systems capable of hotplug, this map could dynamically grow | |
4474 | * as new cpu's are detected in the system via any platform specific | |
4475 | * method, such as ACPI for e.g. | |
4476 | */ | |
4477 | ||
4cef0c61 | 4478 | cpumask_t cpu_present_map __read_mostly; |
1da177e4 LT |
4479 | EXPORT_SYMBOL(cpu_present_map); |
4480 | ||
4481 | #ifndef CONFIG_SMP | |
4cef0c61 | 4482 | cpumask_t cpu_online_map __read_mostly = CPU_MASK_ALL; |
e16b38f7 GB |
4483 | EXPORT_SYMBOL(cpu_online_map); |
4484 | ||
4cef0c61 | 4485 | cpumask_t cpu_possible_map __read_mostly = CPU_MASK_ALL; |
e16b38f7 | 4486 | EXPORT_SYMBOL(cpu_possible_map); |
1da177e4 LT |
4487 | #endif |
4488 | ||
4489 | long sched_getaffinity(pid_t pid, cpumask_t *mask) | |
4490 | { | |
36c8b586 | 4491 | struct task_struct *p; |
1da177e4 | 4492 | int retval; |
1da177e4 | 4493 | |
5be9361c | 4494 | mutex_lock(&sched_hotcpu_mutex); |
1da177e4 LT |
4495 | read_lock(&tasklist_lock); |
4496 | ||
4497 | retval = -ESRCH; | |
4498 | p = find_process_by_pid(pid); | |
4499 | if (!p) | |
4500 | goto out_unlock; | |
4501 | ||
e7834f8f DQ |
4502 | retval = security_task_getscheduler(p); |
4503 | if (retval) | |
4504 | goto out_unlock; | |
4505 | ||
2f7016d9 | 4506 | cpus_and(*mask, p->cpus_allowed, cpu_online_map); |
1da177e4 LT |
4507 | |
4508 | out_unlock: | |
4509 | read_unlock(&tasklist_lock); | |
5be9361c | 4510 | mutex_unlock(&sched_hotcpu_mutex); |
1da177e4 | 4511 | |
9531b62f | 4512 | return retval; |
1da177e4 LT |
4513 | } |
4514 | ||
4515 | /** | |
4516 | * sys_sched_getaffinity - get the cpu affinity of a process | |
4517 | * @pid: pid of the process | |
4518 | * @len: length in bytes of the bitmask pointed to by user_mask_ptr | |
4519 | * @user_mask_ptr: user-space pointer to hold the current cpu mask | |
4520 | */ | |
4521 | asmlinkage long sys_sched_getaffinity(pid_t pid, unsigned int len, | |
4522 | unsigned long __user *user_mask_ptr) | |
4523 | { | |
4524 | int ret; | |
4525 | cpumask_t mask; | |
4526 | ||
4527 | if (len < sizeof(cpumask_t)) | |
4528 | return -EINVAL; | |
4529 | ||
4530 | ret = sched_getaffinity(pid, &mask); | |
4531 | if (ret < 0) | |
4532 | return ret; | |
4533 | ||
4534 | if (copy_to_user(user_mask_ptr, &mask, sizeof(cpumask_t))) | |
4535 | return -EFAULT; | |
4536 | ||
4537 | return sizeof(cpumask_t); | |
4538 | } | |
4539 | ||
4540 | /** | |
4541 | * sys_sched_yield - yield the current processor to other threads. | |
4542 | * | |
dd41f596 IM |
4543 | * This function yields the current CPU to other tasks. If there are no |
4544 | * other threads running on this CPU then this function will return. | |
1da177e4 LT |
4545 | */ |
4546 | asmlinkage long sys_sched_yield(void) | |
4547 | { | |
70b97a7f | 4548 | struct rq *rq = this_rq_lock(); |
1da177e4 LT |
4549 | |
4550 | schedstat_inc(rq, yld_cnt); | |
dd41f596 | 4551 | if (unlikely(rq->nr_running == 1)) |
1da177e4 | 4552 | schedstat_inc(rq, yld_act_empty); |
dd41f596 IM |
4553 | else |
4554 | current->sched_class->yield_task(rq, current); | |
1da177e4 LT |
4555 | |
4556 | /* | |
4557 | * Since we are going to call schedule() anyway, there's | |
4558 | * no need to preempt or enable interrupts: | |
4559 | */ | |
4560 | __release(rq->lock); | |
8a25d5de | 4561 | spin_release(&rq->lock.dep_map, 1, _THIS_IP_); |
1da177e4 LT |
4562 | _raw_spin_unlock(&rq->lock); |
4563 | preempt_enable_no_resched(); | |
4564 | ||
4565 | schedule(); | |
4566 | ||
4567 | return 0; | |
4568 | } | |
4569 | ||
e7b38404 | 4570 | static void __cond_resched(void) |
1da177e4 | 4571 | { |
8e0a43d8 IM |
4572 | #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP |
4573 | __might_sleep(__FILE__, __LINE__); | |
4574 | #endif | |
5bbcfd90 IM |
4575 | /* |
4576 | * The BKS might be reacquired before we have dropped | |
4577 | * PREEMPT_ACTIVE, which could trigger a second | |
4578 | * cond_resched() call. | |
4579 | */ | |
1da177e4 LT |
4580 | do { |
4581 | add_preempt_count(PREEMPT_ACTIVE); | |
4582 | schedule(); | |
4583 | sub_preempt_count(PREEMPT_ACTIVE); | |
4584 | } while (need_resched()); | |
4585 | } | |
4586 | ||
4587 | int __sched cond_resched(void) | |
4588 | { | |
9414232f IM |
4589 | if (need_resched() && !(preempt_count() & PREEMPT_ACTIVE) && |
4590 | system_state == SYSTEM_RUNNING) { | |
1da177e4 LT |
4591 | __cond_resched(); |
4592 | return 1; | |
4593 | } | |
4594 | return 0; | |
4595 | } | |
1da177e4 LT |
4596 | EXPORT_SYMBOL(cond_resched); |
4597 | ||
4598 | /* | |
4599 | * cond_resched_lock() - if a reschedule is pending, drop the given lock, | |
4600 | * call schedule, and on return reacquire the lock. | |
4601 | * | |
4602 | * This works OK both with and without CONFIG_PREEMPT. We do strange low-level | |
4603 | * operations here to prevent schedule() from being called twice (once via | |
4604 | * spin_unlock(), once by hand). | |
4605 | */ | |
95cdf3b7 | 4606 | int cond_resched_lock(spinlock_t *lock) |
1da177e4 | 4607 | { |
6df3cecb JK |
4608 | int ret = 0; |
4609 | ||
1da177e4 LT |
4610 | if (need_lockbreak(lock)) { |
4611 | spin_unlock(lock); | |
4612 | cpu_relax(); | |
6df3cecb | 4613 | ret = 1; |
1da177e4 LT |
4614 | spin_lock(lock); |
4615 | } | |
9414232f | 4616 | if (need_resched() && system_state == SYSTEM_RUNNING) { |
8a25d5de | 4617 | spin_release(&lock->dep_map, 1, _THIS_IP_); |
1da177e4 LT |
4618 | _raw_spin_unlock(lock); |
4619 | preempt_enable_no_resched(); | |
4620 | __cond_resched(); | |
6df3cecb | 4621 | ret = 1; |
1da177e4 | 4622 | spin_lock(lock); |
1da177e4 | 4623 | } |
6df3cecb | 4624 | return ret; |
1da177e4 | 4625 | } |
1da177e4 LT |
4626 | EXPORT_SYMBOL(cond_resched_lock); |
4627 | ||
4628 | int __sched cond_resched_softirq(void) | |
4629 | { | |
4630 | BUG_ON(!in_softirq()); | |
4631 | ||
9414232f | 4632 | if (need_resched() && system_state == SYSTEM_RUNNING) { |
98d82567 | 4633 | local_bh_enable(); |
1da177e4 LT |
4634 | __cond_resched(); |
4635 | local_bh_disable(); | |
4636 | return 1; | |
4637 | } | |
4638 | return 0; | |
4639 | } | |
1da177e4 LT |
4640 | EXPORT_SYMBOL(cond_resched_softirq); |
4641 | ||
1da177e4 LT |
4642 | /** |
4643 | * yield - yield the current processor to other threads. | |
4644 | * | |
72fd4a35 | 4645 | * This is a shortcut for kernel-space yielding - it marks the |
1da177e4 LT |
4646 | * thread runnable and calls sys_sched_yield(). |
4647 | */ | |
4648 | void __sched yield(void) | |
4649 | { | |
4650 | set_current_state(TASK_RUNNING); | |
4651 | sys_sched_yield(); | |
4652 | } | |
1da177e4 LT |
4653 | EXPORT_SYMBOL(yield); |
4654 | ||
4655 | /* | |
4656 | * This task is about to go to sleep on IO. Increment rq->nr_iowait so | |
4657 | * that process accounting knows that this is a task in IO wait state. | |
4658 | * | |
4659 | * But don't do that if it is a deliberate, throttling IO wait (this task | |
4660 | * has set its backing_dev_info: the queue against which it should throttle) | |
4661 | */ | |
4662 | void __sched io_schedule(void) | |
4663 | { | |
70b97a7f | 4664 | struct rq *rq = &__raw_get_cpu_var(runqueues); |
1da177e4 | 4665 | |
0ff92245 | 4666 | delayacct_blkio_start(); |
1da177e4 LT |
4667 | atomic_inc(&rq->nr_iowait); |
4668 | schedule(); | |
4669 | atomic_dec(&rq->nr_iowait); | |
0ff92245 | 4670 | delayacct_blkio_end(); |
1da177e4 | 4671 | } |
1da177e4 LT |
4672 | EXPORT_SYMBOL(io_schedule); |
4673 | ||
4674 | long __sched io_schedule_timeout(long timeout) | |
4675 | { | |
70b97a7f | 4676 | struct rq *rq = &__raw_get_cpu_var(runqueues); |
1da177e4 LT |
4677 | long ret; |
4678 | ||
0ff92245 | 4679 | delayacct_blkio_start(); |
1da177e4 LT |
4680 | atomic_inc(&rq->nr_iowait); |
4681 | ret = schedule_timeout(timeout); | |
4682 | atomic_dec(&rq->nr_iowait); | |
0ff92245 | 4683 | delayacct_blkio_end(); |
1da177e4 LT |
4684 | return ret; |
4685 | } | |
4686 | ||
4687 | /** | |
4688 | * sys_sched_get_priority_max - return maximum RT priority. | |
4689 | * @policy: scheduling class. | |
4690 | * | |
4691 | * this syscall returns the maximum rt_priority that can be used | |
4692 | * by a given scheduling class. | |
4693 | */ | |
4694 | asmlinkage long sys_sched_get_priority_max(int policy) | |
4695 | { | |
4696 | int ret = -EINVAL; | |
4697 | ||
4698 | switch (policy) { | |
4699 | case SCHED_FIFO: | |
4700 | case SCHED_RR: | |
4701 | ret = MAX_USER_RT_PRIO-1; | |
4702 | break; | |
4703 | case SCHED_NORMAL: | |
b0a9499c | 4704 | case SCHED_BATCH: |
dd41f596 | 4705 | case SCHED_IDLE: |
1da177e4 LT |
4706 | ret = 0; |
4707 | break; | |
4708 | } | |
4709 | return ret; | |
4710 | } | |
4711 | ||
4712 | /** | |
4713 | * sys_sched_get_priority_min - return minimum RT priority. | |
4714 | * @policy: scheduling class. | |
4715 | * | |
4716 | * this syscall returns the minimum rt_priority that can be used | |
4717 | * by a given scheduling class. | |
4718 | */ | |
4719 | asmlinkage long sys_sched_get_priority_min(int policy) | |
4720 | { | |
4721 | int ret = -EINVAL; | |
4722 | ||
4723 | switch (policy) { | |
4724 | case SCHED_FIFO: | |
4725 | case SCHED_RR: | |
4726 | ret = 1; | |
4727 | break; | |
4728 | case SCHED_NORMAL: | |
b0a9499c | 4729 | case SCHED_BATCH: |
dd41f596 | 4730 | case SCHED_IDLE: |
1da177e4 LT |
4731 | ret = 0; |
4732 | } | |
4733 | return ret; | |
4734 | } | |
4735 | ||
4736 | /** | |
4737 | * sys_sched_rr_get_interval - return the default timeslice of a process. | |
4738 | * @pid: pid of the process. | |
4739 | * @interval: userspace pointer to the timeslice value. | |
4740 | * | |
4741 | * this syscall writes the default timeslice value of a given process | |
4742 | * into the user-space timespec buffer. A value of '0' means infinity. | |
4743 | */ | |
4744 | asmlinkage | |
4745 | long sys_sched_rr_get_interval(pid_t pid, struct timespec __user *interval) | |
4746 | { | |
36c8b586 | 4747 | struct task_struct *p; |
1da177e4 LT |
4748 | int retval = -EINVAL; |
4749 | struct timespec t; | |
1da177e4 LT |
4750 | |
4751 | if (pid < 0) | |
4752 | goto out_nounlock; | |
4753 | ||
4754 | retval = -ESRCH; | |
4755 | read_lock(&tasklist_lock); | |
4756 | p = find_process_by_pid(pid); | |
4757 | if (!p) | |
4758 | goto out_unlock; | |
4759 | ||
4760 | retval = security_task_getscheduler(p); | |
4761 | if (retval) | |
4762 | goto out_unlock; | |
4763 | ||
b78709cf | 4764 | jiffies_to_timespec(p->policy == SCHED_FIFO ? |
dd41f596 | 4765 | 0 : static_prio_timeslice(p->static_prio), &t); |
1da177e4 LT |
4766 | read_unlock(&tasklist_lock); |
4767 | retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0; | |
4768 | out_nounlock: | |
4769 | return retval; | |
4770 | out_unlock: | |
4771 | read_unlock(&tasklist_lock); | |
4772 | return retval; | |
4773 | } | |
4774 | ||
2ed6e34f | 4775 | static const char stat_nam[] = "RSDTtZX"; |
36c8b586 IM |
4776 | |
4777 | static void show_task(struct task_struct *p) | |
1da177e4 | 4778 | { |
1da177e4 | 4779 | unsigned long free = 0; |
36c8b586 | 4780 | unsigned state; |
1da177e4 | 4781 | |
1da177e4 | 4782 | state = p->state ? __ffs(p->state) + 1 : 0; |
2ed6e34f AM |
4783 | printk("%-13.13s %c", p->comm, |
4784 | state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?'); | |
4bd77321 | 4785 | #if BITS_PER_LONG == 32 |
1da177e4 | 4786 | if (state == TASK_RUNNING) |
4bd77321 | 4787 | printk(" running "); |
1da177e4 | 4788 | else |
4bd77321 | 4789 | printk(" %08lx ", thread_saved_pc(p)); |
1da177e4 LT |
4790 | #else |
4791 | if (state == TASK_RUNNING) | |
4bd77321 | 4792 | printk(" running task "); |
1da177e4 LT |
4793 | else |
4794 | printk(" %016lx ", thread_saved_pc(p)); | |
4795 | #endif | |
4796 | #ifdef CONFIG_DEBUG_STACK_USAGE | |
4797 | { | |
10ebffde | 4798 | unsigned long *n = end_of_stack(p); |
1da177e4 LT |
4799 | while (!*n) |
4800 | n++; | |
10ebffde | 4801 | free = (unsigned long)n - (unsigned long)end_of_stack(p); |
1da177e4 LT |
4802 | } |
4803 | #endif | |
4bd77321 | 4804 | printk("%5lu %5d %6d\n", free, p->pid, p->parent->pid); |
1da177e4 LT |
4805 | |
4806 | if (state != TASK_RUNNING) | |
4807 | show_stack(p, NULL); | |
4808 | } | |
4809 | ||
e59e2ae2 | 4810 | void show_state_filter(unsigned long state_filter) |
1da177e4 | 4811 | { |
36c8b586 | 4812 | struct task_struct *g, *p; |
1da177e4 | 4813 | |
4bd77321 IM |
4814 | #if BITS_PER_LONG == 32 |
4815 | printk(KERN_INFO | |
4816 | " task PC stack pid father\n"); | |
1da177e4 | 4817 | #else |
4bd77321 IM |
4818 | printk(KERN_INFO |
4819 | " task PC stack pid father\n"); | |
1da177e4 LT |
4820 | #endif |
4821 | read_lock(&tasklist_lock); | |
4822 | do_each_thread(g, p) { | |
4823 | /* | |
4824 | * reset the NMI-timeout, listing all files on a slow | |
4825 | * console might take alot of time: | |
4826 | */ | |
4827 | touch_nmi_watchdog(); | |
39bc89fd | 4828 | if (!state_filter || (p->state & state_filter)) |
e59e2ae2 | 4829 | show_task(p); |
1da177e4 LT |
4830 | } while_each_thread(g, p); |
4831 | ||
04c9167f JF |
4832 | touch_all_softlockup_watchdogs(); |
4833 | ||
dd41f596 IM |
4834 | #ifdef CONFIG_SCHED_DEBUG |
4835 | sysrq_sched_debug_show(); | |
4836 | #endif | |
1da177e4 | 4837 | read_unlock(&tasklist_lock); |
e59e2ae2 IM |
4838 | /* |
4839 | * Only show locks if all tasks are dumped: | |
4840 | */ | |
4841 | if (state_filter == -1) | |
4842 | debug_show_all_locks(); | |
1da177e4 LT |
4843 | } |
4844 | ||
1df21055 IM |
4845 | void __cpuinit init_idle_bootup_task(struct task_struct *idle) |
4846 | { | |
dd41f596 | 4847 | idle->sched_class = &idle_sched_class; |
1df21055 IM |
4848 | } |
4849 | ||
f340c0d1 IM |
4850 | /** |
4851 | * init_idle - set up an idle thread for a given CPU | |
4852 | * @idle: task in question | |
4853 | * @cpu: cpu the idle task belongs to | |
4854 | * | |
4855 | * NOTE: this function does not set the idle thread's NEED_RESCHED | |
4856 | * flag, to make booting more robust. | |
4857 | */ | |
5c1e1767 | 4858 | void __cpuinit init_idle(struct task_struct *idle, int cpu) |
1da177e4 | 4859 | { |
70b97a7f | 4860 | struct rq *rq = cpu_rq(cpu); |
1da177e4 LT |
4861 | unsigned long flags; |
4862 | ||
dd41f596 IM |
4863 | __sched_fork(idle); |
4864 | idle->se.exec_start = sched_clock(); | |
4865 | ||
b29739f9 | 4866 | idle->prio = idle->normal_prio = MAX_PRIO; |
1da177e4 | 4867 | idle->cpus_allowed = cpumask_of_cpu(cpu); |
dd41f596 | 4868 | __set_task_cpu(idle, cpu); |
1da177e4 LT |
4869 | |
4870 | spin_lock_irqsave(&rq->lock, flags); | |
4871 | rq->curr = rq->idle = idle; | |
4866cde0 NP |
4872 | #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW) |
4873 | idle->oncpu = 1; | |
4874 | #endif | |
1da177e4 LT |
4875 | spin_unlock_irqrestore(&rq->lock, flags); |
4876 | ||
4877 | /* Set the preempt count _outside_ the spinlocks! */ | |
4878 | #if defined(CONFIG_PREEMPT) && !defined(CONFIG_PREEMPT_BKL) | |
a1261f54 | 4879 | task_thread_info(idle)->preempt_count = (idle->lock_depth >= 0); |
1da177e4 | 4880 | #else |
a1261f54 | 4881 | task_thread_info(idle)->preempt_count = 0; |
1da177e4 | 4882 | #endif |
dd41f596 IM |
4883 | /* |
4884 | * The idle tasks have their own, simple scheduling class: | |
4885 | */ | |
4886 | idle->sched_class = &idle_sched_class; | |
1da177e4 LT |
4887 | } |
4888 | ||
4889 | /* | |
4890 | * In a system that switches off the HZ timer nohz_cpu_mask | |
4891 | * indicates which cpus entered this state. This is used | |
4892 | * in the rcu update to wait only for active cpus. For system | |
4893 | * which do not switch off the HZ timer nohz_cpu_mask should | |
4894 | * always be CPU_MASK_NONE. | |
4895 | */ | |
4896 | cpumask_t nohz_cpu_mask = CPU_MASK_NONE; | |
4897 | ||
dd41f596 IM |
4898 | /* |
4899 | * Increase the granularity value when there are more CPUs, | |
4900 | * because with more CPUs the 'effective latency' as visible | |
4901 | * to users decreases. But the relationship is not linear, | |
4902 | * so pick a second-best guess by going with the log2 of the | |
4903 | * number of CPUs. | |
4904 | * | |
4905 | * This idea comes from the SD scheduler of Con Kolivas: | |
4906 | */ | |
4907 | static inline void sched_init_granularity(void) | |
4908 | { | |
4909 | unsigned int factor = 1 + ilog2(num_online_cpus()); | |
a5968df8 | 4910 | const unsigned long gran_limit = 100000000; |
dd41f596 IM |
4911 | |
4912 | sysctl_sched_granularity *= factor; | |
4913 | if (sysctl_sched_granularity > gran_limit) | |
4914 | sysctl_sched_granularity = gran_limit; | |
4915 | ||
4916 | sysctl_sched_runtime_limit = sysctl_sched_granularity * 4; | |
4917 | sysctl_sched_wakeup_granularity = sysctl_sched_granularity / 2; | |
4918 | } | |
4919 | ||
1da177e4 LT |
4920 | #ifdef CONFIG_SMP |
4921 | /* | |
4922 | * This is how migration works: | |
4923 | * | |
70b97a7f | 4924 | * 1) we queue a struct migration_req structure in the source CPU's |
1da177e4 LT |
4925 | * runqueue and wake up that CPU's migration thread. |
4926 | * 2) we down() the locked semaphore => thread blocks. | |
4927 | * 3) migration thread wakes up (implicitly it forces the migrated | |
4928 | * thread off the CPU) | |
4929 | * 4) it gets the migration request and checks whether the migrated | |
4930 | * task is still in the wrong runqueue. | |
4931 | * 5) if it's in the wrong runqueue then the migration thread removes | |
4932 | * it and puts it into the right queue. | |
4933 | * 6) migration thread up()s the semaphore. | |
4934 | * 7) we wake up and the migration is done. | |
4935 | */ | |
4936 | ||
4937 | /* | |
4938 | * Change a given task's CPU affinity. Migrate the thread to a | |
4939 | * proper CPU and schedule it away if the CPU it's executing on | |
4940 | * is removed from the allowed bitmask. | |
4941 | * | |
4942 | * NOTE: the caller must have a valid reference to the task, the | |
4943 | * task must not exit() & deallocate itself prematurely. The | |
4944 | * call is not atomic; no spinlocks may be held. | |
4945 | */ | |
36c8b586 | 4946 | int set_cpus_allowed(struct task_struct *p, cpumask_t new_mask) |
1da177e4 | 4947 | { |
70b97a7f | 4948 | struct migration_req req; |
1da177e4 | 4949 | unsigned long flags; |
70b97a7f | 4950 | struct rq *rq; |
48f24c4d | 4951 | int ret = 0; |
1da177e4 LT |
4952 | |
4953 | rq = task_rq_lock(p, &flags); | |
4954 | if (!cpus_intersects(new_mask, cpu_online_map)) { | |
4955 | ret = -EINVAL; | |
4956 | goto out; | |
4957 | } | |
4958 | ||
4959 | p->cpus_allowed = new_mask; | |
4960 | /* Can the task run on the task's current CPU? If so, we're done */ | |
4961 | if (cpu_isset(task_cpu(p), new_mask)) | |
4962 | goto out; | |
4963 | ||
4964 | if (migrate_task(p, any_online_cpu(new_mask), &req)) { | |
4965 | /* Need help from migration thread: drop lock and wait. */ | |
4966 | task_rq_unlock(rq, &flags); | |
4967 | wake_up_process(rq->migration_thread); | |
4968 | wait_for_completion(&req.done); | |
4969 | tlb_migrate_finish(p->mm); | |
4970 | return 0; | |
4971 | } | |
4972 | out: | |
4973 | task_rq_unlock(rq, &flags); | |
48f24c4d | 4974 | |
1da177e4 LT |
4975 | return ret; |
4976 | } | |
1da177e4 LT |
4977 | EXPORT_SYMBOL_GPL(set_cpus_allowed); |
4978 | ||
4979 | /* | |
4980 | * Move (not current) task off this cpu, onto dest cpu. We're doing | |
4981 | * this because either it can't run here any more (set_cpus_allowed() | |
4982 | * away from this CPU, or CPU going down), or because we're | |
4983 | * attempting to rebalance this task on exec (sched_exec). | |
4984 | * | |
4985 | * So we race with normal scheduler movements, but that's OK, as long | |
4986 | * as the task is no longer on this CPU. | |
efc30814 KK |
4987 | * |
4988 | * Returns non-zero if task was successfully migrated. | |
1da177e4 | 4989 | */ |
efc30814 | 4990 | static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu) |
1da177e4 | 4991 | { |
70b97a7f | 4992 | struct rq *rq_dest, *rq_src; |
dd41f596 | 4993 | int ret = 0, on_rq; |
1da177e4 LT |
4994 | |
4995 | if (unlikely(cpu_is_offline(dest_cpu))) | |
efc30814 | 4996 | return ret; |
1da177e4 LT |
4997 | |
4998 | rq_src = cpu_rq(src_cpu); | |
4999 | rq_dest = cpu_rq(dest_cpu); | |
5000 | ||
5001 | double_rq_lock(rq_src, rq_dest); | |
5002 | /* Already moved. */ | |
5003 | if (task_cpu(p) != src_cpu) | |
5004 | goto out; | |
5005 | /* Affinity changed (again). */ | |
5006 | if (!cpu_isset(dest_cpu, p->cpus_allowed)) | |
5007 | goto out; | |
5008 | ||
dd41f596 | 5009 | on_rq = p->se.on_rq; |
6e82a3be | 5010 | if (on_rq) |
2e1cb74a | 5011 | deactivate_task(rq_src, p, 0); |
6e82a3be | 5012 | |
1da177e4 | 5013 | set_task_cpu(p, dest_cpu); |
dd41f596 IM |
5014 | if (on_rq) { |
5015 | activate_task(rq_dest, p, 0); | |
5016 | check_preempt_curr(rq_dest, p); | |
1da177e4 | 5017 | } |
efc30814 | 5018 | ret = 1; |
1da177e4 LT |
5019 | out: |
5020 | double_rq_unlock(rq_src, rq_dest); | |
efc30814 | 5021 | return ret; |
1da177e4 LT |
5022 | } |
5023 | ||
5024 | /* | |
5025 | * migration_thread - this is a highprio system thread that performs | |
5026 | * thread migration by bumping thread off CPU then 'pushing' onto | |
5027 | * another runqueue. | |
5028 | */ | |
95cdf3b7 | 5029 | static int migration_thread(void *data) |
1da177e4 | 5030 | { |
1da177e4 | 5031 | int cpu = (long)data; |
70b97a7f | 5032 | struct rq *rq; |
1da177e4 LT |
5033 | |
5034 | rq = cpu_rq(cpu); | |
5035 | BUG_ON(rq->migration_thread != current); | |
5036 | ||
5037 | set_current_state(TASK_INTERRUPTIBLE); | |
5038 | while (!kthread_should_stop()) { | |
70b97a7f | 5039 | struct migration_req *req; |
1da177e4 | 5040 | struct list_head *head; |
1da177e4 | 5041 | |
1da177e4 LT |
5042 | spin_lock_irq(&rq->lock); |
5043 | ||
5044 | if (cpu_is_offline(cpu)) { | |
5045 | spin_unlock_irq(&rq->lock); | |
5046 | goto wait_to_die; | |
5047 | } | |
5048 | ||
5049 | if (rq->active_balance) { | |
5050 | active_load_balance(rq, cpu); | |
5051 | rq->active_balance = 0; | |
5052 | } | |
5053 | ||
5054 | head = &rq->migration_queue; | |
5055 | ||
5056 | if (list_empty(head)) { | |
5057 | spin_unlock_irq(&rq->lock); | |
5058 | schedule(); | |
5059 | set_current_state(TASK_INTERRUPTIBLE); | |
5060 | continue; | |
5061 | } | |
70b97a7f | 5062 | req = list_entry(head->next, struct migration_req, list); |
1da177e4 LT |
5063 | list_del_init(head->next); |
5064 | ||
674311d5 NP |
5065 | spin_unlock(&rq->lock); |
5066 | __migrate_task(req->task, cpu, req->dest_cpu); | |
5067 | local_irq_enable(); | |
1da177e4 LT |
5068 | |
5069 | complete(&req->done); | |
5070 | } | |
5071 | __set_current_state(TASK_RUNNING); | |
5072 | return 0; | |
5073 | ||
5074 | wait_to_die: | |
5075 | /* Wait for kthread_stop */ | |
5076 | set_current_state(TASK_INTERRUPTIBLE); | |
5077 | while (!kthread_should_stop()) { | |
5078 | schedule(); | |
5079 | set_current_state(TASK_INTERRUPTIBLE); | |
5080 | } | |
5081 | __set_current_state(TASK_RUNNING); | |
5082 | return 0; | |
5083 | } | |
5084 | ||
5085 | #ifdef CONFIG_HOTPLUG_CPU | |
054b9108 KK |
5086 | /* |
5087 | * Figure out where task on dead CPU should go, use force if neccessary. | |
5088 | * NOTE: interrupts should be disabled by the caller | |
5089 | */ | |
48f24c4d | 5090 | static void move_task_off_dead_cpu(int dead_cpu, struct task_struct *p) |
1da177e4 | 5091 | { |
efc30814 | 5092 | unsigned long flags; |
1da177e4 | 5093 | cpumask_t mask; |
70b97a7f IM |
5094 | struct rq *rq; |
5095 | int dest_cpu; | |
1da177e4 | 5096 | |
efc30814 | 5097 | restart: |
1da177e4 LT |
5098 | /* On same node? */ |
5099 | mask = node_to_cpumask(cpu_to_node(dead_cpu)); | |
48f24c4d | 5100 | cpus_and(mask, mask, p->cpus_allowed); |
1da177e4 LT |
5101 | dest_cpu = any_online_cpu(mask); |
5102 | ||
5103 | /* On any allowed CPU? */ | |
5104 | if (dest_cpu == NR_CPUS) | |
48f24c4d | 5105 | dest_cpu = any_online_cpu(p->cpus_allowed); |
1da177e4 LT |
5106 | |
5107 | /* No more Mr. Nice Guy. */ | |
5108 | if (dest_cpu == NR_CPUS) { | |
48f24c4d IM |
5109 | rq = task_rq_lock(p, &flags); |
5110 | cpus_setall(p->cpus_allowed); | |
5111 | dest_cpu = any_online_cpu(p->cpus_allowed); | |
efc30814 | 5112 | task_rq_unlock(rq, &flags); |
1da177e4 LT |
5113 | |
5114 | /* | |
5115 | * Don't tell them about moving exiting tasks or | |
5116 | * kernel threads (both mm NULL), since they never | |
5117 | * leave kernel. | |
5118 | */ | |
48f24c4d | 5119 | if (p->mm && printk_ratelimit()) |
1da177e4 LT |
5120 | printk(KERN_INFO "process %d (%s) no " |
5121 | "longer affine to cpu%d\n", | |
48f24c4d | 5122 | p->pid, p->comm, dead_cpu); |
1da177e4 | 5123 | } |
48f24c4d | 5124 | if (!__migrate_task(p, dead_cpu, dest_cpu)) |
efc30814 | 5125 | goto restart; |
1da177e4 LT |
5126 | } |
5127 | ||
5128 | /* | |
5129 | * While a dead CPU has no uninterruptible tasks queued at this point, | |
5130 | * it might still have a nonzero ->nr_uninterruptible counter, because | |
5131 | * for performance reasons the counter is not stricly tracking tasks to | |
5132 | * their home CPUs. So we just add the counter to another CPU's counter, | |
5133 | * to keep the global sum constant after CPU-down: | |
5134 | */ | |
70b97a7f | 5135 | static void migrate_nr_uninterruptible(struct rq *rq_src) |
1da177e4 | 5136 | { |
70b97a7f | 5137 | struct rq *rq_dest = cpu_rq(any_online_cpu(CPU_MASK_ALL)); |
1da177e4 LT |
5138 | unsigned long flags; |
5139 | ||
5140 | local_irq_save(flags); | |
5141 | double_rq_lock(rq_src, rq_dest); | |
5142 | rq_dest->nr_uninterruptible += rq_src->nr_uninterruptible; | |
5143 | rq_src->nr_uninterruptible = 0; | |
5144 | double_rq_unlock(rq_src, rq_dest); | |
5145 | local_irq_restore(flags); | |
5146 | } | |
5147 | ||
5148 | /* Run through task list and migrate tasks from the dead cpu. */ | |
5149 | static void migrate_live_tasks(int src_cpu) | |
5150 | { | |
48f24c4d | 5151 | struct task_struct *p, *t; |
1da177e4 LT |
5152 | |
5153 | write_lock_irq(&tasklist_lock); | |
5154 | ||
48f24c4d IM |
5155 | do_each_thread(t, p) { |
5156 | if (p == current) | |
1da177e4 LT |
5157 | continue; |
5158 | ||
48f24c4d IM |
5159 | if (task_cpu(p) == src_cpu) |
5160 | move_task_off_dead_cpu(src_cpu, p); | |
5161 | } while_each_thread(t, p); | |
1da177e4 LT |
5162 | |
5163 | write_unlock_irq(&tasklist_lock); | |
5164 | } | |
5165 | ||
dd41f596 IM |
5166 | /* |
5167 | * Schedules idle task to be the next runnable task on current CPU. | |
1da177e4 | 5168 | * It does so by boosting its priority to highest possible and adding it to |
48f24c4d | 5169 | * the _front_ of the runqueue. Used by CPU offline code. |
1da177e4 LT |
5170 | */ |
5171 | void sched_idle_next(void) | |
5172 | { | |
48f24c4d | 5173 | int this_cpu = smp_processor_id(); |
70b97a7f | 5174 | struct rq *rq = cpu_rq(this_cpu); |
1da177e4 LT |
5175 | struct task_struct *p = rq->idle; |
5176 | unsigned long flags; | |
5177 | ||
5178 | /* cpu has to be offline */ | |
48f24c4d | 5179 | BUG_ON(cpu_online(this_cpu)); |
1da177e4 | 5180 | |
48f24c4d IM |
5181 | /* |
5182 | * Strictly not necessary since rest of the CPUs are stopped by now | |
5183 | * and interrupts disabled on the current cpu. | |
1da177e4 LT |
5184 | */ |
5185 | spin_lock_irqsave(&rq->lock, flags); | |
5186 | ||
dd41f596 | 5187 | __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1); |
48f24c4d IM |
5188 | |
5189 | /* Add idle task to the _front_ of its priority queue: */ | |
dd41f596 | 5190 | activate_idle_task(p, rq); |
1da177e4 LT |
5191 | |
5192 | spin_unlock_irqrestore(&rq->lock, flags); | |
5193 | } | |
5194 | ||
48f24c4d IM |
5195 | /* |
5196 | * Ensures that the idle task is using init_mm right before its cpu goes | |
1da177e4 LT |
5197 | * offline. |
5198 | */ | |
5199 | void idle_task_exit(void) | |
5200 | { | |
5201 | struct mm_struct *mm = current->active_mm; | |
5202 | ||
5203 | BUG_ON(cpu_online(smp_processor_id())); | |
5204 | ||
5205 | if (mm != &init_mm) | |
5206 | switch_mm(mm, &init_mm, current); | |
5207 | mmdrop(mm); | |
5208 | } | |
5209 | ||
054b9108 | 5210 | /* called under rq->lock with disabled interrupts */ |
36c8b586 | 5211 | static void migrate_dead(unsigned int dead_cpu, struct task_struct *p) |
1da177e4 | 5212 | { |
70b97a7f | 5213 | struct rq *rq = cpu_rq(dead_cpu); |
1da177e4 LT |
5214 | |
5215 | /* Must be exiting, otherwise would be on tasklist. */ | |
48f24c4d | 5216 | BUG_ON(p->exit_state != EXIT_ZOMBIE && p->exit_state != EXIT_DEAD); |
1da177e4 LT |
5217 | |
5218 | /* Cannot have done final schedule yet: would have vanished. */ | |
c394cc9f | 5219 | BUG_ON(p->state == TASK_DEAD); |
1da177e4 | 5220 | |
48f24c4d | 5221 | get_task_struct(p); |
1da177e4 LT |
5222 | |
5223 | /* | |
5224 | * Drop lock around migration; if someone else moves it, | |
5225 | * that's OK. No task can be added to this CPU, so iteration is | |
5226 | * fine. | |
054b9108 | 5227 | * NOTE: interrupts should be left disabled --dev@ |
1da177e4 | 5228 | */ |
054b9108 | 5229 | spin_unlock(&rq->lock); |
48f24c4d | 5230 | move_task_off_dead_cpu(dead_cpu, p); |
054b9108 | 5231 | spin_lock(&rq->lock); |
1da177e4 | 5232 | |
48f24c4d | 5233 | put_task_struct(p); |
1da177e4 LT |
5234 | } |
5235 | ||
5236 | /* release_task() removes task from tasklist, so we won't find dead tasks. */ | |
5237 | static void migrate_dead_tasks(unsigned int dead_cpu) | |
5238 | { | |
70b97a7f | 5239 | struct rq *rq = cpu_rq(dead_cpu); |
dd41f596 | 5240 | struct task_struct *next; |
48f24c4d | 5241 | |
dd41f596 IM |
5242 | for ( ; ; ) { |
5243 | if (!rq->nr_running) | |
5244 | break; | |
a8e504d2 | 5245 | update_rq_clock(rq); |
ff95f3df | 5246 | next = pick_next_task(rq, rq->curr); |
dd41f596 IM |
5247 | if (!next) |
5248 | break; | |
5249 | migrate_dead(dead_cpu, next); | |
e692ab53 | 5250 | |
1da177e4 LT |
5251 | } |
5252 | } | |
5253 | #endif /* CONFIG_HOTPLUG_CPU */ | |
5254 | ||
e692ab53 NP |
5255 | #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL) |
5256 | ||
5257 | static struct ctl_table sd_ctl_dir[] = { | |
e0361851 AD |
5258 | { |
5259 | .procname = "sched_domain", | |
5260 | .mode = 0755, | |
5261 | }, | |
e692ab53 NP |
5262 | {0,}, |
5263 | }; | |
5264 | ||
5265 | static struct ctl_table sd_ctl_root[] = { | |
e0361851 AD |
5266 | { |
5267 | .procname = "kernel", | |
5268 | .mode = 0755, | |
5269 | .child = sd_ctl_dir, | |
5270 | }, | |
e692ab53 NP |
5271 | {0,}, |
5272 | }; | |
5273 | ||
5274 | static struct ctl_table *sd_alloc_ctl_entry(int n) | |
5275 | { | |
5276 | struct ctl_table *entry = | |
5277 | kmalloc(n * sizeof(struct ctl_table), GFP_KERNEL); | |
5278 | ||
5279 | BUG_ON(!entry); | |
5280 | memset(entry, 0, n * sizeof(struct ctl_table)); | |
5281 | ||
5282 | return entry; | |
5283 | } | |
5284 | ||
5285 | static void | |
e0361851 | 5286 | set_table_entry(struct ctl_table *entry, |
e692ab53 NP |
5287 | const char *procname, void *data, int maxlen, |
5288 | mode_t mode, proc_handler *proc_handler) | |
5289 | { | |
e692ab53 NP |
5290 | entry->procname = procname; |
5291 | entry->data = data; | |
5292 | entry->maxlen = maxlen; | |
5293 | entry->mode = mode; | |
5294 | entry->proc_handler = proc_handler; | |
5295 | } | |
5296 | ||
5297 | static struct ctl_table * | |
5298 | sd_alloc_ctl_domain_table(struct sched_domain *sd) | |
5299 | { | |
5300 | struct ctl_table *table = sd_alloc_ctl_entry(14); | |
5301 | ||
e0361851 | 5302 | set_table_entry(&table[0], "min_interval", &sd->min_interval, |
e692ab53 | 5303 | sizeof(long), 0644, proc_doulongvec_minmax); |
e0361851 | 5304 | set_table_entry(&table[1], "max_interval", &sd->max_interval, |
e692ab53 | 5305 | sizeof(long), 0644, proc_doulongvec_minmax); |
e0361851 | 5306 | set_table_entry(&table[2], "busy_idx", &sd->busy_idx, |
e692ab53 | 5307 | sizeof(int), 0644, proc_dointvec_minmax); |
e0361851 | 5308 | set_table_entry(&table[3], "idle_idx", &sd->idle_idx, |
e692ab53 | 5309 | sizeof(int), 0644, proc_dointvec_minmax); |
e0361851 | 5310 | set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx, |
e692ab53 | 5311 | sizeof(int), 0644, proc_dointvec_minmax); |
e0361851 | 5312 | set_table_entry(&table[5], "wake_idx", &sd->wake_idx, |
e692ab53 | 5313 | sizeof(int), 0644, proc_dointvec_minmax); |
e0361851 | 5314 | set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx, |
e692ab53 | 5315 | sizeof(int), 0644, proc_dointvec_minmax); |
e0361851 | 5316 | set_table_entry(&table[7], "busy_factor", &sd->busy_factor, |
e692ab53 | 5317 | sizeof(int), 0644, proc_dointvec_minmax); |
e0361851 | 5318 | set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct, |
e692ab53 | 5319 | sizeof(int), 0644, proc_dointvec_minmax); |
e0361851 | 5320 | set_table_entry(&table[10], "cache_nice_tries", |
e692ab53 NP |
5321 | &sd->cache_nice_tries, |
5322 | sizeof(int), 0644, proc_dointvec_minmax); | |
e0361851 | 5323 | set_table_entry(&table[12], "flags", &sd->flags, |
e692ab53 NP |
5324 | sizeof(int), 0644, proc_dointvec_minmax); |
5325 | ||
5326 | return table; | |
5327 | } | |
5328 | ||
5329 | static ctl_table *sd_alloc_ctl_cpu_table(int cpu) | |
5330 | { | |
5331 | struct ctl_table *entry, *table; | |
5332 | struct sched_domain *sd; | |
5333 | int domain_num = 0, i; | |
5334 | char buf[32]; | |
5335 | ||
5336 | for_each_domain(cpu, sd) | |
5337 | domain_num++; | |
5338 | entry = table = sd_alloc_ctl_entry(domain_num + 1); | |
5339 | ||
5340 | i = 0; | |
5341 | for_each_domain(cpu, sd) { | |
5342 | snprintf(buf, 32, "domain%d", i); | |
e692ab53 NP |
5343 | entry->procname = kstrdup(buf, GFP_KERNEL); |
5344 | entry->mode = 0755; | |
5345 | entry->child = sd_alloc_ctl_domain_table(sd); | |
5346 | entry++; | |
5347 | i++; | |
5348 | } | |
5349 | return table; | |
5350 | } | |
5351 | ||
5352 | static struct ctl_table_header *sd_sysctl_header; | |
5353 | static void init_sched_domain_sysctl(void) | |
5354 | { | |
5355 | int i, cpu_num = num_online_cpus(); | |
5356 | struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1); | |
5357 | char buf[32]; | |
5358 | ||
5359 | sd_ctl_dir[0].child = entry; | |
5360 | ||
5361 | for (i = 0; i < cpu_num; i++, entry++) { | |
5362 | snprintf(buf, 32, "cpu%d", i); | |
e692ab53 NP |
5363 | entry->procname = kstrdup(buf, GFP_KERNEL); |
5364 | entry->mode = 0755; | |
5365 | entry->child = sd_alloc_ctl_cpu_table(i); | |
5366 | } | |
5367 | sd_sysctl_header = register_sysctl_table(sd_ctl_root); | |
5368 | } | |
5369 | #else | |
5370 | static void init_sched_domain_sysctl(void) | |
5371 | { | |
5372 | } | |
5373 | #endif | |
5374 | ||
1da177e4 LT |
5375 | /* |
5376 | * migration_call - callback that gets triggered when a CPU is added. | |
5377 | * Here we can start up the necessary migration thread for the new CPU. | |
5378 | */ | |
48f24c4d IM |
5379 | static int __cpuinit |
5380 | migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) | |
1da177e4 | 5381 | { |
1da177e4 | 5382 | struct task_struct *p; |
48f24c4d | 5383 | int cpu = (long)hcpu; |
1da177e4 | 5384 | unsigned long flags; |
70b97a7f | 5385 | struct rq *rq; |
1da177e4 LT |
5386 | |
5387 | switch (action) { | |
5be9361c GS |
5388 | case CPU_LOCK_ACQUIRE: |
5389 | mutex_lock(&sched_hotcpu_mutex); | |
5390 | break; | |
5391 | ||
1da177e4 | 5392 | case CPU_UP_PREPARE: |
8bb78442 | 5393 | case CPU_UP_PREPARE_FROZEN: |
dd41f596 | 5394 | p = kthread_create(migration_thread, hcpu, "migration/%d", cpu); |
1da177e4 LT |
5395 | if (IS_ERR(p)) |
5396 | return NOTIFY_BAD; | |
1da177e4 LT |
5397 | kthread_bind(p, cpu); |
5398 | /* Must be high prio: stop_machine expects to yield to it. */ | |
5399 | rq = task_rq_lock(p, &flags); | |
dd41f596 | 5400 | __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1); |
1da177e4 LT |
5401 | task_rq_unlock(rq, &flags); |
5402 | cpu_rq(cpu)->migration_thread = p; | |
5403 | break; | |
48f24c4d | 5404 | |
1da177e4 | 5405 | case CPU_ONLINE: |
8bb78442 | 5406 | case CPU_ONLINE_FROZEN: |
1da177e4 LT |
5407 | /* Strictly unneccessary, as first user will wake it. */ |
5408 | wake_up_process(cpu_rq(cpu)->migration_thread); | |
5409 | break; | |
48f24c4d | 5410 | |
1da177e4 LT |
5411 | #ifdef CONFIG_HOTPLUG_CPU |
5412 | case CPU_UP_CANCELED: | |
8bb78442 | 5413 | case CPU_UP_CANCELED_FROZEN: |
fc75cdfa HC |
5414 | if (!cpu_rq(cpu)->migration_thread) |
5415 | break; | |
1da177e4 | 5416 | /* Unbind it from offline cpu so it can run. Fall thru. */ |
a4c4af7c HC |
5417 | kthread_bind(cpu_rq(cpu)->migration_thread, |
5418 | any_online_cpu(cpu_online_map)); | |
1da177e4 LT |
5419 | kthread_stop(cpu_rq(cpu)->migration_thread); |
5420 | cpu_rq(cpu)->migration_thread = NULL; | |
5421 | break; | |
48f24c4d | 5422 | |
1da177e4 | 5423 | case CPU_DEAD: |
8bb78442 | 5424 | case CPU_DEAD_FROZEN: |
1da177e4 LT |
5425 | migrate_live_tasks(cpu); |
5426 | rq = cpu_rq(cpu); | |
5427 | kthread_stop(rq->migration_thread); | |
5428 | rq->migration_thread = NULL; | |
5429 | /* Idle task back to normal (off runqueue, low prio) */ | |
5430 | rq = task_rq_lock(rq->idle, &flags); | |
a8e504d2 | 5431 | update_rq_clock(rq); |
2e1cb74a | 5432 | deactivate_task(rq, rq->idle, 0); |
1da177e4 | 5433 | rq->idle->static_prio = MAX_PRIO; |
dd41f596 IM |
5434 | __setscheduler(rq, rq->idle, SCHED_NORMAL, 0); |
5435 | rq->idle->sched_class = &idle_sched_class; | |
1da177e4 LT |
5436 | migrate_dead_tasks(cpu); |
5437 | task_rq_unlock(rq, &flags); | |
5438 | migrate_nr_uninterruptible(rq); | |
5439 | BUG_ON(rq->nr_running != 0); | |
5440 | ||
5441 | /* No need to migrate the tasks: it was best-effort if | |
5be9361c | 5442 | * they didn't take sched_hotcpu_mutex. Just wake up |
1da177e4 LT |
5443 | * the requestors. */ |
5444 | spin_lock_irq(&rq->lock); | |
5445 | while (!list_empty(&rq->migration_queue)) { | |
70b97a7f IM |
5446 | struct migration_req *req; |
5447 | ||
1da177e4 | 5448 | req = list_entry(rq->migration_queue.next, |
70b97a7f | 5449 | struct migration_req, list); |
1da177e4 LT |
5450 | list_del_init(&req->list); |
5451 | complete(&req->done); | |
5452 | } | |
5453 | spin_unlock_irq(&rq->lock); | |
5454 | break; | |
5455 | #endif | |
5be9361c GS |
5456 | case CPU_LOCK_RELEASE: |
5457 | mutex_unlock(&sched_hotcpu_mutex); | |
5458 | break; | |
1da177e4 LT |
5459 | } |
5460 | return NOTIFY_OK; | |
5461 | } | |
5462 | ||
5463 | /* Register at highest priority so that task migration (migrate_all_tasks) | |
5464 | * happens before everything else. | |
5465 | */ | |
26c2143b | 5466 | static struct notifier_block __cpuinitdata migration_notifier = { |
1da177e4 LT |
5467 | .notifier_call = migration_call, |
5468 | .priority = 10 | |
5469 | }; | |
5470 | ||
5471 | int __init migration_init(void) | |
5472 | { | |
5473 | void *cpu = (void *)(long)smp_processor_id(); | |
07dccf33 | 5474 | int err; |
48f24c4d IM |
5475 | |
5476 | /* Start one for the boot CPU: */ | |
07dccf33 AM |
5477 | err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu); |
5478 | BUG_ON(err == NOTIFY_BAD); | |
1da177e4 LT |
5479 | migration_call(&migration_notifier, CPU_ONLINE, cpu); |
5480 | register_cpu_notifier(&migration_notifier); | |
48f24c4d | 5481 | |
1da177e4 LT |
5482 | return 0; |
5483 | } | |
5484 | #endif | |
5485 | ||
5486 | #ifdef CONFIG_SMP | |
476f3534 CL |
5487 | |
5488 | /* Number of possible processor ids */ | |
5489 | int nr_cpu_ids __read_mostly = NR_CPUS; | |
5490 | EXPORT_SYMBOL(nr_cpu_ids); | |
5491 | ||
1a20ff27 | 5492 | #undef SCHED_DOMAIN_DEBUG |
1da177e4 LT |
5493 | #ifdef SCHED_DOMAIN_DEBUG |
5494 | static void sched_domain_debug(struct sched_domain *sd, int cpu) | |
5495 | { | |
5496 | int level = 0; | |
5497 | ||
41c7ce9a NP |
5498 | if (!sd) { |
5499 | printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu); | |
5500 | return; | |
5501 | } | |
5502 | ||
1da177e4 LT |
5503 | printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu); |
5504 | ||
5505 | do { | |
5506 | int i; | |
5507 | char str[NR_CPUS]; | |
5508 | struct sched_group *group = sd->groups; | |
5509 | cpumask_t groupmask; | |
5510 | ||
5511 | cpumask_scnprintf(str, NR_CPUS, sd->span); | |
5512 | cpus_clear(groupmask); | |
5513 | ||
5514 | printk(KERN_DEBUG); | |
5515 | for (i = 0; i < level + 1; i++) | |
5516 | printk(" "); | |
5517 | printk("domain %d: ", level); | |
5518 | ||
5519 | if (!(sd->flags & SD_LOAD_BALANCE)) { | |
5520 | printk("does not load-balance\n"); | |
5521 | if (sd->parent) | |
33859f7f MOS |
5522 | printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain" |
5523 | " has parent"); | |
1da177e4 LT |
5524 | break; |
5525 | } | |
5526 | ||
5527 | printk("span %s\n", str); | |
5528 | ||
5529 | if (!cpu_isset(cpu, sd->span)) | |
33859f7f MOS |
5530 | printk(KERN_ERR "ERROR: domain->span does not contain " |
5531 | "CPU%d\n", cpu); | |
1da177e4 | 5532 | if (!cpu_isset(cpu, group->cpumask)) |
33859f7f MOS |
5533 | printk(KERN_ERR "ERROR: domain->groups does not contain" |
5534 | " CPU%d\n", cpu); | |
1da177e4 LT |
5535 | |
5536 | printk(KERN_DEBUG); | |
5537 | for (i = 0; i < level + 2; i++) | |
5538 | printk(" "); | |
5539 | printk("groups:"); | |
5540 | do { | |
5541 | if (!group) { | |
5542 | printk("\n"); | |
5543 | printk(KERN_ERR "ERROR: group is NULL\n"); | |
5544 | break; | |
5545 | } | |
5546 | ||
5517d86b | 5547 | if (!group->__cpu_power) { |
1da177e4 | 5548 | printk("\n"); |
33859f7f MOS |
5549 | printk(KERN_ERR "ERROR: domain->cpu_power not " |
5550 | "set\n"); | |
1da177e4 LT |
5551 | } |
5552 | ||
5553 | if (!cpus_weight(group->cpumask)) { | |
5554 | printk("\n"); | |
5555 | printk(KERN_ERR "ERROR: empty group\n"); | |
5556 | } | |
5557 | ||
5558 | if (cpus_intersects(groupmask, group->cpumask)) { | |
5559 | printk("\n"); | |
5560 | printk(KERN_ERR "ERROR: repeated CPUs\n"); | |
5561 | } | |
5562 | ||
5563 | cpus_or(groupmask, groupmask, group->cpumask); | |
5564 | ||
5565 | cpumask_scnprintf(str, NR_CPUS, group->cpumask); | |
5566 | printk(" %s", str); | |
5567 | ||
5568 | group = group->next; | |
5569 | } while (group != sd->groups); | |
5570 | printk("\n"); | |
5571 | ||
5572 | if (!cpus_equal(sd->span, groupmask)) | |
33859f7f MOS |
5573 | printk(KERN_ERR "ERROR: groups don't span " |
5574 | "domain->span\n"); | |
1da177e4 LT |
5575 | |
5576 | level++; | |
5577 | sd = sd->parent; | |
33859f7f MOS |
5578 | if (!sd) |
5579 | continue; | |
1da177e4 | 5580 | |
33859f7f MOS |
5581 | if (!cpus_subset(groupmask, sd->span)) |
5582 | printk(KERN_ERR "ERROR: parent span is not a superset " | |
5583 | "of domain->span\n"); | |
1da177e4 LT |
5584 | |
5585 | } while (sd); | |
5586 | } | |
5587 | #else | |
48f24c4d | 5588 | # define sched_domain_debug(sd, cpu) do { } while (0) |
1da177e4 LT |
5589 | #endif |
5590 | ||
1a20ff27 | 5591 | static int sd_degenerate(struct sched_domain *sd) |
245af2c7 SS |
5592 | { |
5593 | if (cpus_weight(sd->span) == 1) | |
5594 | return 1; | |
5595 | ||
5596 | /* Following flags need at least 2 groups */ | |
5597 | if (sd->flags & (SD_LOAD_BALANCE | | |
5598 | SD_BALANCE_NEWIDLE | | |
5599 | SD_BALANCE_FORK | | |
89c4710e SS |
5600 | SD_BALANCE_EXEC | |
5601 | SD_SHARE_CPUPOWER | | |
5602 | SD_SHARE_PKG_RESOURCES)) { | |
245af2c7 SS |
5603 | if (sd->groups != sd->groups->next) |
5604 | return 0; | |
5605 | } | |
5606 | ||
5607 | /* Following flags don't use groups */ | |
5608 | if (sd->flags & (SD_WAKE_IDLE | | |
5609 | SD_WAKE_AFFINE | | |
5610 | SD_WAKE_BALANCE)) | |
5611 | return 0; | |
5612 | ||
5613 | return 1; | |
5614 | } | |
5615 | ||
48f24c4d IM |
5616 | static int |
5617 | sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent) | |
245af2c7 SS |
5618 | { |
5619 | unsigned long cflags = sd->flags, pflags = parent->flags; | |
5620 | ||
5621 | if (sd_degenerate(parent)) | |
5622 | return 1; | |
5623 | ||
5624 | if (!cpus_equal(sd->span, parent->span)) | |
5625 | return 0; | |
5626 | ||
5627 | /* Does parent contain flags not in child? */ | |
5628 | /* WAKE_BALANCE is a subset of WAKE_AFFINE */ | |
5629 | if (cflags & SD_WAKE_AFFINE) | |
5630 | pflags &= ~SD_WAKE_BALANCE; | |
5631 | /* Flags needing groups don't count if only 1 group in parent */ | |
5632 | if (parent->groups == parent->groups->next) { | |
5633 | pflags &= ~(SD_LOAD_BALANCE | | |
5634 | SD_BALANCE_NEWIDLE | | |
5635 | SD_BALANCE_FORK | | |
89c4710e SS |
5636 | SD_BALANCE_EXEC | |
5637 | SD_SHARE_CPUPOWER | | |
5638 | SD_SHARE_PKG_RESOURCES); | |
245af2c7 SS |
5639 | } |
5640 | if (~cflags & pflags) | |
5641 | return 0; | |
5642 | ||
5643 | return 1; | |
5644 | } | |
5645 | ||
1da177e4 LT |
5646 | /* |
5647 | * Attach the domain 'sd' to 'cpu' as its base domain. Callers must | |
5648 | * hold the hotplug lock. | |
5649 | */ | |
9c1cfda2 | 5650 | static void cpu_attach_domain(struct sched_domain *sd, int cpu) |
1da177e4 | 5651 | { |
70b97a7f | 5652 | struct rq *rq = cpu_rq(cpu); |
245af2c7 SS |
5653 | struct sched_domain *tmp; |
5654 | ||
5655 | /* Remove the sched domains which do not contribute to scheduling. */ | |
5656 | for (tmp = sd; tmp; tmp = tmp->parent) { | |
5657 | struct sched_domain *parent = tmp->parent; | |
5658 | if (!parent) | |
5659 | break; | |
1a848870 | 5660 | if (sd_parent_degenerate(tmp, parent)) { |
245af2c7 | 5661 | tmp->parent = parent->parent; |
1a848870 SS |
5662 | if (parent->parent) |
5663 | parent->parent->child = tmp; | |
5664 | } | |
245af2c7 SS |
5665 | } |
5666 | ||
1a848870 | 5667 | if (sd && sd_degenerate(sd)) { |
245af2c7 | 5668 | sd = sd->parent; |
1a848870 SS |
5669 | if (sd) |
5670 | sd->child = NULL; | |
5671 | } | |
1da177e4 LT |
5672 | |
5673 | sched_domain_debug(sd, cpu); | |
5674 | ||
674311d5 | 5675 | rcu_assign_pointer(rq->sd, sd); |
1da177e4 LT |
5676 | } |
5677 | ||
5678 | /* cpus with isolated domains */ | |
67af63a6 | 5679 | static cpumask_t cpu_isolated_map = CPU_MASK_NONE; |
1da177e4 LT |
5680 | |
5681 | /* Setup the mask of cpus configured for isolated domains */ | |
5682 | static int __init isolated_cpu_setup(char *str) | |
5683 | { | |
5684 | int ints[NR_CPUS], i; | |
5685 | ||
5686 | str = get_options(str, ARRAY_SIZE(ints), ints); | |
5687 | cpus_clear(cpu_isolated_map); | |
5688 | for (i = 1; i <= ints[0]; i++) | |
5689 | if (ints[i] < NR_CPUS) | |
5690 | cpu_set(ints[i], cpu_isolated_map); | |
5691 | return 1; | |
5692 | } | |
5693 | ||
5694 | __setup ("isolcpus=", isolated_cpu_setup); | |
5695 | ||
5696 | /* | |
6711cab4 SS |
5697 | * init_sched_build_groups takes the cpumask we wish to span, and a pointer |
5698 | * to a function which identifies what group(along with sched group) a CPU | |
5699 | * belongs to. The return value of group_fn must be a >= 0 and < NR_CPUS | |
5700 | * (due to the fact that we keep track of groups covered with a cpumask_t). | |
1da177e4 LT |
5701 | * |
5702 | * init_sched_build_groups will build a circular linked list of the groups | |
5703 | * covered by the given span, and will set each group's ->cpumask correctly, | |
5704 | * and ->cpu_power to 0. | |
5705 | */ | |
a616058b | 5706 | static void |
6711cab4 SS |
5707 | init_sched_build_groups(cpumask_t span, const cpumask_t *cpu_map, |
5708 | int (*group_fn)(int cpu, const cpumask_t *cpu_map, | |
5709 | struct sched_group **sg)) | |
1da177e4 LT |
5710 | { |
5711 | struct sched_group *first = NULL, *last = NULL; | |
5712 | cpumask_t covered = CPU_MASK_NONE; | |
5713 | int i; | |
5714 | ||
5715 | for_each_cpu_mask(i, span) { | |
6711cab4 SS |
5716 | struct sched_group *sg; |
5717 | int group = group_fn(i, cpu_map, &sg); | |
1da177e4 LT |
5718 | int j; |
5719 | ||
5720 | if (cpu_isset(i, covered)) | |
5721 | continue; | |
5722 | ||
5723 | sg->cpumask = CPU_MASK_NONE; | |
5517d86b | 5724 | sg->__cpu_power = 0; |
1da177e4 LT |
5725 | |
5726 | for_each_cpu_mask(j, span) { | |
6711cab4 | 5727 | if (group_fn(j, cpu_map, NULL) != group) |
1da177e4 LT |
5728 | continue; |
5729 | ||
5730 | cpu_set(j, covered); | |
5731 | cpu_set(j, sg->cpumask); | |
5732 | } | |
5733 | if (!first) | |
5734 | first = sg; | |
5735 | if (last) | |
5736 | last->next = sg; | |
5737 | last = sg; | |
5738 | } | |
5739 | last->next = first; | |
5740 | } | |
5741 | ||
9c1cfda2 | 5742 | #define SD_NODES_PER_DOMAIN 16 |
1da177e4 | 5743 | |
9c1cfda2 | 5744 | #ifdef CONFIG_NUMA |
198e2f18 | 5745 | |
9c1cfda2 JH |
5746 | /** |
5747 | * find_next_best_node - find the next node to include in a sched_domain | |
5748 | * @node: node whose sched_domain we're building | |
5749 | * @used_nodes: nodes already in the sched_domain | |
5750 | * | |
5751 | * Find the next node to include in a given scheduling domain. Simply | |
5752 | * finds the closest node not already in the @used_nodes map. | |
5753 | * | |
5754 | * Should use nodemask_t. | |
5755 | */ | |
5756 | static int find_next_best_node(int node, unsigned long *used_nodes) | |
5757 | { | |
5758 | int i, n, val, min_val, best_node = 0; | |
5759 | ||
5760 | min_val = INT_MAX; | |
5761 | ||
5762 | for (i = 0; i < MAX_NUMNODES; i++) { | |
5763 | /* Start at @node */ | |
5764 | n = (node + i) % MAX_NUMNODES; | |
5765 | ||
5766 | if (!nr_cpus_node(n)) | |
5767 | continue; | |
5768 | ||
5769 | /* Skip already used nodes */ | |
5770 | if (test_bit(n, used_nodes)) | |
5771 | continue; | |
5772 | ||
5773 | /* Simple min distance search */ | |
5774 | val = node_distance(node, n); | |
5775 | ||
5776 | if (val < min_val) { | |
5777 | min_val = val; | |
5778 | best_node = n; | |
5779 | } | |
5780 | } | |
5781 | ||
5782 | set_bit(best_node, used_nodes); | |
5783 | return best_node; | |
5784 | } | |
5785 | ||
5786 | /** | |
5787 | * sched_domain_node_span - get a cpumask for a node's sched_domain | |
5788 | * @node: node whose cpumask we're constructing | |
5789 | * @size: number of nodes to include in this span | |
5790 | * | |
5791 | * Given a node, construct a good cpumask for its sched_domain to span. It | |
5792 | * should be one that prevents unnecessary balancing, but also spreads tasks | |
5793 | * out optimally. | |
5794 | */ | |
5795 | static cpumask_t sched_domain_node_span(int node) | |
5796 | { | |
9c1cfda2 | 5797 | DECLARE_BITMAP(used_nodes, MAX_NUMNODES); |
48f24c4d IM |
5798 | cpumask_t span, nodemask; |
5799 | int i; | |
9c1cfda2 JH |
5800 | |
5801 | cpus_clear(span); | |
5802 | bitmap_zero(used_nodes, MAX_NUMNODES); | |
5803 | ||
5804 | nodemask = node_to_cpumask(node); | |
5805 | cpus_or(span, span, nodemask); | |
5806 | set_bit(node, used_nodes); | |
5807 | ||
5808 | for (i = 1; i < SD_NODES_PER_DOMAIN; i++) { | |
5809 | int next_node = find_next_best_node(node, used_nodes); | |
48f24c4d | 5810 | |
9c1cfda2 JH |
5811 | nodemask = node_to_cpumask(next_node); |
5812 | cpus_or(span, span, nodemask); | |
5813 | } | |
5814 | ||
5815 | return span; | |
5816 | } | |
5817 | #endif | |
5818 | ||
5c45bf27 | 5819 | int sched_smt_power_savings = 0, sched_mc_power_savings = 0; |
48f24c4d | 5820 | |
9c1cfda2 | 5821 | /* |
48f24c4d | 5822 | * SMT sched-domains: |
9c1cfda2 | 5823 | */ |
1da177e4 LT |
5824 | #ifdef CONFIG_SCHED_SMT |
5825 | static DEFINE_PER_CPU(struct sched_domain, cpu_domains); | |
6711cab4 | 5826 | static DEFINE_PER_CPU(struct sched_group, sched_group_cpus); |
48f24c4d | 5827 | |
6711cab4 SS |
5828 | static int cpu_to_cpu_group(int cpu, const cpumask_t *cpu_map, |
5829 | struct sched_group **sg) | |
1da177e4 | 5830 | { |
6711cab4 SS |
5831 | if (sg) |
5832 | *sg = &per_cpu(sched_group_cpus, cpu); | |
1da177e4 LT |
5833 | return cpu; |
5834 | } | |
5835 | #endif | |
5836 | ||
48f24c4d IM |
5837 | /* |
5838 | * multi-core sched-domains: | |
5839 | */ | |
1e9f28fa SS |
5840 | #ifdef CONFIG_SCHED_MC |
5841 | static DEFINE_PER_CPU(struct sched_domain, core_domains); | |
6711cab4 | 5842 | static DEFINE_PER_CPU(struct sched_group, sched_group_core); |
1e9f28fa SS |
5843 | #endif |
5844 | ||
5845 | #if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT) | |
6711cab4 SS |
5846 | static int cpu_to_core_group(int cpu, const cpumask_t *cpu_map, |
5847 | struct sched_group **sg) | |
1e9f28fa | 5848 | { |
6711cab4 | 5849 | int group; |
a616058b SS |
5850 | cpumask_t mask = cpu_sibling_map[cpu]; |
5851 | cpus_and(mask, mask, *cpu_map); | |
6711cab4 SS |
5852 | group = first_cpu(mask); |
5853 | if (sg) | |
5854 | *sg = &per_cpu(sched_group_core, group); | |
5855 | return group; | |
1e9f28fa SS |
5856 | } |
5857 | #elif defined(CONFIG_SCHED_MC) | |
6711cab4 SS |
5858 | static int cpu_to_core_group(int cpu, const cpumask_t *cpu_map, |
5859 | struct sched_group **sg) | |
1e9f28fa | 5860 | { |
6711cab4 SS |
5861 | if (sg) |
5862 | *sg = &per_cpu(sched_group_core, cpu); | |
1e9f28fa SS |
5863 | return cpu; |
5864 | } | |
5865 | #endif | |
5866 | ||
1da177e4 | 5867 | static DEFINE_PER_CPU(struct sched_domain, phys_domains); |
6711cab4 | 5868 | static DEFINE_PER_CPU(struct sched_group, sched_group_phys); |
48f24c4d | 5869 | |
6711cab4 SS |
5870 | static int cpu_to_phys_group(int cpu, const cpumask_t *cpu_map, |
5871 | struct sched_group **sg) | |
1da177e4 | 5872 | { |
6711cab4 | 5873 | int group; |
48f24c4d | 5874 | #ifdef CONFIG_SCHED_MC |
1e9f28fa | 5875 | cpumask_t mask = cpu_coregroup_map(cpu); |
a616058b | 5876 | cpus_and(mask, mask, *cpu_map); |
6711cab4 | 5877 | group = first_cpu(mask); |
1e9f28fa | 5878 | #elif defined(CONFIG_SCHED_SMT) |
a616058b SS |
5879 | cpumask_t mask = cpu_sibling_map[cpu]; |
5880 | cpus_and(mask, mask, *cpu_map); | |
6711cab4 | 5881 | group = first_cpu(mask); |
1da177e4 | 5882 | #else |
6711cab4 | 5883 | group = cpu; |
1da177e4 | 5884 | #endif |
6711cab4 SS |
5885 | if (sg) |
5886 | *sg = &per_cpu(sched_group_phys, group); | |
5887 | return group; | |
1da177e4 LT |
5888 | } |
5889 | ||
5890 | #ifdef CONFIG_NUMA | |
1da177e4 | 5891 | /* |
9c1cfda2 JH |
5892 | * The init_sched_build_groups can't handle what we want to do with node |
5893 | * groups, so roll our own. Now each node has its own list of groups which | |
5894 | * gets dynamically allocated. | |
1da177e4 | 5895 | */ |
9c1cfda2 | 5896 | static DEFINE_PER_CPU(struct sched_domain, node_domains); |
d1b55138 | 5897 | static struct sched_group **sched_group_nodes_bycpu[NR_CPUS]; |
1da177e4 | 5898 | |
9c1cfda2 | 5899 | static DEFINE_PER_CPU(struct sched_domain, allnodes_domains); |
6711cab4 | 5900 | static DEFINE_PER_CPU(struct sched_group, sched_group_allnodes); |
9c1cfda2 | 5901 | |
6711cab4 SS |
5902 | static int cpu_to_allnodes_group(int cpu, const cpumask_t *cpu_map, |
5903 | struct sched_group **sg) | |
9c1cfda2 | 5904 | { |
6711cab4 SS |
5905 | cpumask_t nodemask = node_to_cpumask(cpu_to_node(cpu)); |
5906 | int group; | |
5907 | ||
5908 | cpus_and(nodemask, nodemask, *cpu_map); | |
5909 | group = first_cpu(nodemask); | |
5910 | ||
5911 | if (sg) | |
5912 | *sg = &per_cpu(sched_group_allnodes, group); | |
5913 | return group; | |
1da177e4 | 5914 | } |
6711cab4 | 5915 | |
08069033 SS |
5916 | static void init_numa_sched_groups_power(struct sched_group *group_head) |
5917 | { | |
5918 | struct sched_group *sg = group_head; | |
5919 | int j; | |
5920 | ||
5921 | if (!sg) | |
5922 | return; | |
5923 | next_sg: | |
5924 | for_each_cpu_mask(j, sg->cpumask) { | |
5925 | struct sched_domain *sd; | |
5926 | ||
5927 | sd = &per_cpu(phys_domains, j); | |
5928 | if (j != first_cpu(sd->groups->cpumask)) { | |
5929 | /* | |
5930 | * Only add "power" once for each | |
5931 | * physical package. | |
5932 | */ | |
5933 | continue; | |
5934 | } | |
5935 | ||
5517d86b | 5936 | sg_inc_cpu_power(sg, sd->groups->__cpu_power); |
08069033 SS |
5937 | } |
5938 | sg = sg->next; | |
5939 | if (sg != group_head) | |
5940 | goto next_sg; | |
5941 | } | |
1da177e4 LT |
5942 | #endif |
5943 | ||
a616058b | 5944 | #ifdef CONFIG_NUMA |
51888ca2 SV |
5945 | /* Free memory allocated for various sched_group structures */ |
5946 | static void free_sched_groups(const cpumask_t *cpu_map) | |
5947 | { | |
a616058b | 5948 | int cpu, i; |
51888ca2 SV |
5949 | |
5950 | for_each_cpu_mask(cpu, *cpu_map) { | |
51888ca2 SV |
5951 | struct sched_group **sched_group_nodes |
5952 | = sched_group_nodes_bycpu[cpu]; | |
5953 | ||
51888ca2 SV |
5954 | if (!sched_group_nodes) |
5955 | continue; | |
5956 | ||
5957 | for (i = 0; i < MAX_NUMNODES; i++) { | |
5958 | cpumask_t nodemask = node_to_cpumask(i); | |
5959 | struct sched_group *oldsg, *sg = sched_group_nodes[i]; | |
5960 | ||
5961 | cpus_and(nodemask, nodemask, *cpu_map); | |
5962 | if (cpus_empty(nodemask)) | |
5963 | continue; | |
5964 | ||
5965 | if (sg == NULL) | |
5966 | continue; | |
5967 | sg = sg->next; | |
5968 | next_sg: | |
5969 | oldsg = sg; | |
5970 | sg = sg->next; | |
5971 | kfree(oldsg); | |
5972 | if (oldsg != sched_group_nodes[i]) | |
5973 | goto next_sg; | |
5974 | } | |
5975 | kfree(sched_group_nodes); | |
5976 | sched_group_nodes_bycpu[cpu] = NULL; | |
5977 | } | |
51888ca2 | 5978 | } |
a616058b SS |
5979 | #else |
5980 | static void free_sched_groups(const cpumask_t *cpu_map) | |
5981 | { | |
5982 | } | |
5983 | #endif | |
51888ca2 | 5984 | |
89c4710e SS |
5985 | /* |
5986 | * Initialize sched groups cpu_power. | |
5987 | * | |
5988 | * cpu_power indicates the capacity of sched group, which is used while | |
5989 | * distributing the load between different sched groups in a sched domain. | |
5990 | * Typically cpu_power for all the groups in a sched domain will be same unless | |
5991 | * there are asymmetries in the topology. If there are asymmetries, group | |
5992 | * having more cpu_power will pickup more load compared to the group having | |
5993 | * less cpu_power. | |
5994 | * | |
5995 | * cpu_power will be a multiple of SCHED_LOAD_SCALE. This multiple represents | |
5996 | * the maximum number of tasks a group can handle in the presence of other idle | |
5997 | * or lightly loaded groups in the same sched domain. | |
5998 | */ | |
5999 | static void init_sched_groups_power(int cpu, struct sched_domain *sd) | |
6000 | { | |
6001 | struct sched_domain *child; | |
6002 | struct sched_group *group; | |
6003 | ||
6004 | WARN_ON(!sd || !sd->groups); | |
6005 | ||
6006 | if (cpu != first_cpu(sd->groups->cpumask)) | |
6007 | return; | |
6008 | ||
6009 | child = sd->child; | |
6010 | ||
5517d86b ED |
6011 | sd->groups->__cpu_power = 0; |
6012 | ||
89c4710e SS |
6013 | /* |
6014 | * For perf policy, if the groups in child domain share resources | |
6015 | * (for example cores sharing some portions of the cache hierarchy | |
6016 | * or SMT), then set this domain groups cpu_power such that each group | |
6017 | * can handle only one task, when there are other idle groups in the | |
6018 | * same sched domain. | |
6019 | */ | |
6020 | if (!child || (!(sd->flags & SD_POWERSAVINGS_BALANCE) && | |
6021 | (child->flags & | |
6022 | (SD_SHARE_CPUPOWER | SD_SHARE_PKG_RESOURCES)))) { | |
5517d86b | 6023 | sg_inc_cpu_power(sd->groups, SCHED_LOAD_SCALE); |
89c4710e SS |
6024 | return; |
6025 | } | |
6026 | ||
89c4710e SS |
6027 | /* |
6028 | * add cpu_power of each child group to this groups cpu_power | |
6029 | */ | |
6030 | group = child->groups; | |
6031 | do { | |
5517d86b | 6032 | sg_inc_cpu_power(sd->groups, group->__cpu_power); |
89c4710e SS |
6033 | group = group->next; |
6034 | } while (group != child->groups); | |
6035 | } | |
6036 | ||
1da177e4 | 6037 | /* |
1a20ff27 DG |
6038 | * Build sched domains for a given set of cpus and attach the sched domains |
6039 | * to the individual cpus | |
1da177e4 | 6040 | */ |
51888ca2 | 6041 | static int build_sched_domains(const cpumask_t *cpu_map) |
1da177e4 LT |
6042 | { |
6043 | int i; | |
d1b55138 JH |
6044 | #ifdef CONFIG_NUMA |
6045 | struct sched_group **sched_group_nodes = NULL; | |
6711cab4 | 6046 | int sd_allnodes = 0; |
d1b55138 JH |
6047 | |
6048 | /* | |
6049 | * Allocate the per-node list of sched groups | |
6050 | */ | |
dd41f596 | 6051 | sched_group_nodes = kzalloc(sizeof(struct sched_group *)*MAX_NUMNODES, |
d3a5aa98 | 6052 | GFP_KERNEL); |
d1b55138 JH |
6053 | if (!sched_group_nodes) { |
6054 | printk(KERN_WARNING "Can not alloc sched group node list\n"); | |
51888ca2 | 6055 | return -ENOMEM; |
d1b55138 JH |
6056 | } |
6057 | sched_group_nodes_bycpu[first_cpu(*cpu_map)] = sched_group_nodes; | |
6058 | #endif | |
1da177e4 LT |
6059 | |
6060 | /* | |
1a20ff27 | 6061 | * Set up domains for cpus specified by the cpu_map. |
1da177e4 | 6062 | */ |
1a20ff27 | 6063 | for_each_cpu_mask(i, *cpu_map) { |
1da177e4 LT |
6064 | struct sched_domain *sd = NULL, *p; |
6065 | cpumask_t nodemask = node_to_cpumask(cpu_to_node(i)); | |
6066 | ||
1a20ff27 | 6067 | cpus_and(nodemask, nodemask, *cpu_map); |
1da177e4 LT |
6068 | |
6069 | #ifdef CONFIG_NUMA | |
dd41f596 IM |
6070 | if (cpus_weight(*cpu_map) > |
6071 | SD_NODES_PER_DOMAIN*cpus_weight(nodemask)) { | |
9c1cfda2 JH |
6072 | sd = &per_cpu(allnodes_domains, i); |
6073 | *sd = SD_ALLNODES_INIT; | |
6074 | sd->span = *cpu_map; | |
6711cab4 | 6075 | cpu_to_allnodes_group(i, cpu_map, &sd->groups); |
9c1cfda2 | 6076 | p = sd; |
6711cab4 | 6077 | sd_allnodes = 1; |
9c1cfda2 JH |
6078 | } else |
6079 | p = NULL; | |
6080 | ||
1da177e4 | 6081 | sd = &per_cpu(node_domains, i); |
1da177e4 | 6082 | *sd = SD_NODE_INIT; |
9c1cfda2 JH |
6083 | sd->span = sched_domain_node_span(cpu_to_node(i)); |
6084 | sd->parent = p; | |
1a848870 SS |
6085 | if (p) |
6086 | p->child = sd; | |
9c1cfda2 | 6087 | cpus_and(sd->span, sd->span, *cpu_map); |
1da177e4 LT |
6088 | #endif |
6089 | ||
6090 | p = sd; | |
6091 | sd = &per_cpu(phys_domains, i); | |
1da177e4 LT |
6092 | *sd = SD_CPU_INIT; |
6093 | sd->span = nodemask; | |
6094 | sd->parent = p; | |
1a848870 SS |
6095 | if (p) |
6096 | p->child = sd; | |
6711cab4 | 6097 | cpu_to_phys_group(i, cpu_map, &sd->groups); |
1da177e4 | 6098 | |
1e9f28fa SS |
6099 | #ifdef CONFIG_SCHED_MC |
6100 | p = sd; | |
6101 | sd = &per_cpu(core_domains, i); | |
1e9f28fa SS |
6102 | *sd = SD_MC_INIT; |
6103 | sd->span = cpu_coregroup_map(i); | |
6104 | cpus_and(sd->span, sd->span, *cpu_map); | |
6105 | sd->parent = p; | |
1a848870 | 6106 | p->child = sd; |
6711cab4 | 6107 | cpu_to_core_group(i, cpu_map, &sd->groups); |
1e9f28fa SS |
6108 | #endif |
6109 | ||
1da177e4 LT |
6110 | #ifdef CONFIG_SCHED_SMT |
6111 | p = sd; | |
6112 | sd = &per_cpu(cpu_domains, i); | |
1da177e4 LT |
6113 | *sd = SD_SIBLING_INIT; |
6114 | sd->span = cpu_sibling_map[i]; | |
1a20ff27 | 6115 | cpus_and(sd->span, sd->span, *cpu_map); |
1da177e4 | 6116 | sd->parent = p; |
1a848870 | 6117 | p->child = sd; |
6711cab4 | 6118 | cpu_to_cpu_group(i, cpu_map, &sd->groups); |
1da177e4 LT |
6119 | #endif |
6120 | } | |
6121 | ||
6122 | #ifdef CONFIG_SCHED_SMT | |
6123 | /* Set up CPU (sibling) groups */ | |
9c1cfda2 | 6124 | for_each_cpu_mask(i, *cpu_map) { |
1da177e4 | 6125 | cpumask_t this_sibling_map = cpu_sibling_map[i]; |
1a20ff27 | 6126 | cpus_and(this_sibling_map, this_sibling_map, *cpu_map); |
1da177e4 LT |
6127 | if (i != first_cpu(this_sibling_map)) |
6128 | continue; | |
6129 | ||
dd41f596 IM |
6130 | init_sched_build_groups(this_sibling_map, cpu_map, |
6131 | &cpu_to_cpu_group); | |
1da177e4 LT |
6132 | } |
6133 | #endif | |
6134 | ||
1e9f28fa SS |
6135 | #ifdef CONFIG_SCHED_MC |
6136 | /* Set up multi-core groups */ | |
6137 | for_each_cpu_mask(i, *cpu_map) { | |
6138 | cpumask_t this_core_map = cpu_coregroup_map(i); | |
6139 | cpus_and(this_core_map, this_core_map, *cpu_map); | |
6140 | if (i != first_cpu(this_core_map)) | |
6141 | continue; | |
dd41f596 IM |
6142 | init_sched_build_groups(this_core_map, cpu_map, |
6143 | &cpu_to_core_group); | |
1e9f28fa SS |
6144 | } |
6145 | #endif | |
6146 | ||
1da177e4 LT |
6147 | /* Set up physical groups */ |
6148 | for (i = 0; i < MAX_NUMNODES; i++) { | |
6149 | cpumask_t nodemask = node_to_cpumask(i); | |
6150 | ||
1a20ff27 | 6151 | cpus_and(nodemask, nodemask, *cpu_map); |
1da177e4 LT |
6152 | if (cpus_empty(nodemask)) |
6153 | continue; | |
6154 | ||
6711cab4 | 6155 | init_sched_build_groups(nodemask, cpu_map, &cpu_to_phys_group); |
1da177e4 LT |
6156 | } |
6157 | ||
6158 | #ifdef CONFIG_NUMA | |
6159 | /* Set up node groups */ | |
6711cab4 | 6160 | if (sd_allnodes) |
dd41f596 IM |
6161 | init_sched_build_groups(*cpu_map, cpu_map, |
6162 | &cpu_to_allnodes_group); | |
9c1cfda2 JH |
6163 | |
6164 | for (i = 0; i < MAX_NUMNODES; i++) { | |
6165 | /* Set up node groups */ | |
6166 | struct sched_group *sg, *prev; | |
6167 | cpumask_t nodemask = node_to_cpumask(i); | |
6168 | cpumask_t domainspan; | |
6169 | cpumask_t covered = CPU_MASK_NONE; | |
6170 | int j; | |
6171 | ||
6172 | cpus_and(nodemask, nodemask, *cpu_map); | |
d1b55138 JH |
6173 | if (cpus_empty(nodemask)) { |
6174 | sched_group_nodes[i] = NULL; | |
9c1cfda2 | 6175 | continue; |
d1b55138 | 6176 | } |
9c1cfda2 JH |
6177 | |
6178 | domainspan = sched_domain_node_span(i); | |
6179 | cpus_and(domainspan, domainspan, *cpu_map); | |
6180 | ||
15f0b676 | 6181 | sg = kmalloc_node(sizeof(struct sched_group), GFP_KERNEL, i); |
51888ca2 SV |
6182 | if (!sg) { |
6183 | printk(KERN_WARNING "Can not alloc domain group for " | |
6184 | "node %d\n", i); | |
6185 | goto error; | |
6186 | } | |
9c1cfda2 JH |
6187 | sched_group_nodes[i] = sg; |
6188 | for_each_cpu_mask(j, nodemask) { | |
6189 | struct sched_domain *sd; | |
9761eea8 | 6190 | |
9c1cfda2 JH |
6191 | sd = &per_cpu(node_domains, j); |
6192 | sd->groups = sg; | |
9c1cfda2 | 6193 | } |
5517d86b | 6194 | sg->__cpu_power = 0; |
9c1cfda2 | 6195 | sg->cpumask = nodemask; |
51888ca2 | 6196 | sg->next = sg; |
9c1cfda2 JH |
6197 | cpus_or(covered, covered, nodemask); |
6198 | prev = sg; | |
6199 | ||
6200 | for (j = 0; j < MAX_NUMNODES; j++) { | |
6201 | cpumask_t tmp, notcovered; | |
6202 | int n = (i + j) % MAX_NUMNODES; | |
6203 | ||
6204 | cpus_complement(notcovered, covered); | |
6205 | cpus_and(tmp, notcovered, *cpu_map); | |
6206 | cpus_and(tmp, tmp, domainspan); | |
6207 | if (cpus_empty(tmp)) | |
6208 | break; | |
6209 | ||
6210 | nodemask = node_to_cpumask(n); | |
6211 | cpus_and(tmp, tmp, nodemask); | |
6212 | if (cpus_empty(tmp)) | |
6213 | continue; | |
6214 | ||
15f0b676 SV |
6215 | sg = kmalloc_node(sizeof(struct sched_group), |
6216 | GFP_KERNEL, i); | |
9c1cfda2 JH |
6217 | if (!sg) { |
6218 | printk(KERN_WARNING | |
6219 | "Can not alloc domain group for node %d\n", j); | |
51888ca2 | 6220 | goto error; |
9c1cfda2 | 6221 | } |
5517d86b | 6222 | sg->__cpu_power = 0; |
9c1cfda2 | 6223 | sg->cpumask = tmp; |
51888ca2 | 6224 | sg->next = prev->next; |
9c1cfda2 JH |
6225 | cpus_or(covered, covered, tmp); |
6226 | prev->next = sg; | |
6227 | prev = sg; | |
6228 | } | |
9c1cfda2 | 6229 | } |
1da177e4 LT |
6230 | #endif |
6231 | ||
6232 | /* Calculate CPU power for physical packages and nodes */ | |
5c45bf27 | 6233 | #ifdef CONFIG_SCHED_SMT |
1a20ff27 | 6234 | for_each_cpu_mask(i, *cpu_map) { |
dd41f596 IM |
6235 | struct sched_domain *sd = &per_cpu(cpu_domains, i); |
6236 | ||
89c4710e | 6237 | init_sched_groups_power(i, sd); |
5c45bf27 | 6238 | } |
1da177e4 | 6239 | #endif |
1e9f28fa | 6240 | #ifdef CONFIG_SCHED_MC |
5c45bf27 | 6241 | for_each_cpu_mask(i, *cpu_map) { |
dd41f596 IM |
6242 | struct sched_domain *sd = &per_cpu(core_domains, i); |
6243 | ||
89c4710e | 6244 | init_sched_groups_power(i, sd); |
5c45bf27 SS |
6245 | } |
6246 | #endif | |
1e9f28fa | 6247 | |
5c45bf27 | 6248 | for_each_cpu_mask(i, *cpu_map) { |
dd41f596 IM |
6249 | struct sched_domain *sd = &per_cpu(phys_domains, i); |
6250 | ||
89c4710e | 6251 | init_sched_groups_power(i, sd); |
1da177e4 LT |
6252 | } |
6253 | ||
9c1cfda2 | 6254 | #ifdef CONFIG_NUMA |
08069033 SS |
6255 | for (i = 0; i < MAX_NUMNODES; i++) |
6256 | init_numa_sched_groups_power(sched_group_nodes[i]); | |
9c1cfda2 | 6257 | |
6711cab4 SS |
6258 | if (sd_allnodes) { |
6259 | struct sched_group *sg; | |
f712c0c7 | 6260 | |
6711cab4 | 6261 | cpu_to_allnodes_group(first_cpu(*cpu_map), cpu_map, &sg); |
f712c0c7 SS |
6262 | init_numa_sched_groups_power(sg); |
6263 | } | |
9c1cfda2 JH |
6264 | #endif |
6265 | ||
1da177e4 | 6266 | /* Attach the domains */ |
1a20ff27 | 6267 | for_each_cpu_mask(i, *cpu_map) { |
1da177e4 LT |
6268 | struct sched_domain *sd; |
6269 | #ifdef CONFIG_SCHED_SMT | |
6270 | sd = &per_cpu(cpu_domains, i); | |
1e9f28fa SS |
6271 | #elif defined(CONFIG_SCHED_MC) |
6272 | sd = &per_cpu(core_domains, i); | |
1da177e4 LT |
6273 | #else |
6274 | sd = &per_cpu(phys_domains, i); | |
6275 | #endif | |
6276 | cpu_attach_domain(sd, i); | |
6277 | } | |
51888ca2 SV |
6278 | |
6279 | return 0; | |
6280 | ||
a616058b | 6281 | #ifdef CONFIG_NUMA |
51888ca2 SV |
6282 | error: |
6283 | free_sched_groups(cpu_map); | |
6284 | return -ENOMEM; | |
a616058b | 6285 | #endif |
1da177e4 | 6286 | } |
1a20ff27 DG |
6287 | /* |
6288 | * Set up scheduler domains and groups. Callers must hold the hotplug lock. | |
6289 | */ | |
51888ca2 | 6290 | static int arch_init_sched_domains(const cpumask_t *cpu_map) |
1a20ff27 DG |
6291 | { |
6292 | cpumask_t cpu_default_map; | |
51888ca2 | 6293 | int err; |
1da177e4 | 6294 | |
1a20ff27 DG |
6295 | /* |
6296 | * Setup mask for cpus without special case scheduling requirements. | |
6297 | * For now this just excludes isolated cpus, but could be used to | |
6298 | * exclude other special cases in the future. | |
6299 | */ | |
6300 | cpus_andnot(cpu_default_map, *cpu_map, cpu_isolated_map); | |
6301 | ||
51888ca2 SV |
6302 | err = build_sched_domains(&cpu_default_map); |
6303 | ||
6304 | return err; | |
1a20ff27 DG |
6305 | } |
6306 | ||
6307 | static void arch_destroy_sched_domains(const cpumask_t *cpu_map) | |
1da177e4 | 6308 | { |
51888ca2 | 6309 | free_sched_groups(cpu_map); |
9c1cfda2 | 6310 | } |
1da177e4 | 6311 | |
1a20ff27 DG |
6312 | /* |
6313 | * Detach sched domains from a group of cpus specified in cpu_map | |
6314 | * These cpus will now be attached to the NULL domain | |
6315 | */ | |
858119e1 | 6316 | static void detach_destroy_domains(const cpumask_t *cpu_map) |
1a20ff27 DG |
6317 | { |
6318 | int i; | |
6319 | ||
6320 | for_each_cpu_mask(i, *cpu_map) | |
6321 | cpu_attach_domain(NULL, i); | |
6322 | synchronize_sched(); | |
6323 | arch_destroy_sched_domains(cpu_map); | |
6324 | } | |
6325 | ||
6326 | /* | |
6327 | * Partition sched domains as specified by the cpumasks below. | |
6328 | * This attaches all cpus from the cpumasks to the NULL domain, | |
6329 | * waits for a RCU quiescent period, recalculates sched | |
6330 | * domain information and then attaches them back to the | |
6331 | * correct sched domains | |
6332 | * Call with hotplug lock held | |
6333 | */ | |
51888ca2 | 6334 | int partition_sched_domains(cpumask_t *partition1, cpumask_t *partition2) |
1a20ff27 DG |
6335 | { |
6336 | cpumask_t change_map; | |
51888ca2 | 6337 | int err = 0; |
1a20ff27 DG |
6338 | |
6339 | cpus_and(*partition1, *partition1, cpu_online_map); | |
6340 | cpus_and(*partition2, *partition2, cpu_online_map); | |
6341 | cpus_or(change_map, *partition1, *partition2); | |
6342 | ||
6343 | /* Detach sched domains from all of the affected cpus */ | |
6344 | detach_destroy_domains(&change_map); | |
6345 | if (!cpus_empty(*partition1)) | |
51888ca2 SV |
6346 | err = build_sched_domains(partition1); |
6347 | if (!err && !cpus_empty(*partition2)) | |
6348 | err = build_sched_domains(partition2); | |
6349 | ||
6350 | return err; | |
1a20ff27 DG |
6351 | } |
6352 | ||
5c45bf27 | 6353 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) |
6707de00 | 6354 | static int arch_reinit_sched_domains(void) |
5c45bf27 SS |
6355 | { |
6356 | int err; | |
6357 | ||
5be9361c | 6358 | mutex_lock(&sched_hotcpu_mutex); |
5c45bf27 SS |
6359 | detach_destroy_domains(&cpu_online_map); |
6360 | err = arch_init_sched_domains(&cpu_online_map); | |
5be9361c | 6361 | mutex_unlock(&sched_hotcpu_mutex); |
5c45bf27 SS |
6362 | |
6363 | return err; | |
6364 | } | |
6365 | ||
6366 | static ssize_t sched_power_savings_store(const char *buf, size_t count, int smt) | |
6367 | { | |
6368 | int ret; | |
6369 | ||
6370 | if (buf[0] != '0' && buf[0] != '1') | |
6371 | return -EINVAL; | |
6372 | ||
6373 | if (smt) | |
6374 | sched_smt_power_savings = (buf[0] == '1'); | |
6375 | else | |
6376 | sched_mc_power_savings = (buf[0] == '1'); | |
6377 | ||
6378 | ret = arch_reinit_sched_domains(); | |
6379 | ||
6380 | return ret ? ret : count; | |
6381 | } | |
6382 | ||
5c45bf27 SS |
6383 | #ifdef CONFIG_SCHED_MC |
6384 | static ssize_t sched_mc_power_savings_show(struct sys_device *dev, char *page) | |
6385 | { | |
6386 | return sprintf(page, "%u\n", sched_mc_power_savings); | |
6387 | } | |
48f24c4d IM |
6388 | static ssize_t sched_mc_power_savings_store(struct sys_device *dev, |
6389 | const char *buf, size_t count) | |
5c45bf27 SS |
6390 | { |
6391 | return sched_power_savings_store(buf, count, 0); | |
6392 | } | |
6707de00 AB |
6393 | static SYSDEV_ATTR(sched_mc_power_savings, 0644, sched_mc_power_savings_show, |
6394 | sched_mc_power_savings_store); | |
5c45bf27 SS |
6395 | #endif |
6396 | ||
6397 | #ifdef CONFIG_SCHED_SMT | |
6398 | static ssize_t sched_smt_power_savings_show(struct sys_device *dev, char *page) | |
6399 | { | |
6400 | return sprintf(page, "%u\n", sched_smt_power_savings); | |
6401 | } | |
48f24c4d IM |
6402 | static ssize_t sched_smt_power_savings_store(struct sys_device *dev, |
6403 | const char *buf, size_t count) | |
5c45bf27 SS |
6404 | { |
6405 | return sched_power_savings_store(buf, count, 1); | |
6406 | } | |
6707de00 AB |
6407 | static SYSDEV_ATTR(sched_smt_power_savings, 0644, sched_smt_power_savings_show, |
6408 | sched_smt_power_savings_store); | |
6409 | #endif | |
6410 | ||
6411 | int sched_create_sysfs_power_savings_entries(struct sysdev_class *cls) | |
6412 | { | |
6413 | int err = 0; | |
6414 | ||
6415 | #ifdef CONFIG_SCHED_SMT | |
6416 | if (smt_capable()) | |
6417 | err = sysfs_create_file(&cls->kset.kobj, | |
6418 | &attr_sched_smt_power_savings.attr); | |
6419 | #endif | |
6420 | #ifdef CONFIG_SCHED_MC | |
6421 | if (!err && mc_capable()) | |
6422 | err = sysfs_create_file(&cls->kset.kobj, | |
6423 | &attr_sched_mc_power_savings.attr); | |
6424 | #endif | |
6425 | return err; | |
6426 | } | |
5c45bf27 SS |
6427 | #endif |
6428 | ||
1da177e4 LT |
6429 | /* |
6430 | * Force a reinitialization of the sched domains hierarchy. The domains | |
6431 | * and groups cannot be updated in place without racing with the balancing | |
41c7ce9a | 6432 | * code, so we temporarily attach all running cpus to the NULL domain |
1da177e4 LT |
6433 | * which will prevent rebalancing while the sched domains are recalculated. |
6434 | */ | |
6435 | static int update_sched_domains(struct notifier_block *nfb, | |
6436 | unsigned long action, void *hcpu) | |
6437 | { | |
1da177e4 LT |
6438 | switch (action) { |
6439 | case CPU_UP_PREPARE: | |
8bb78442 | 6440 | case CPU_UP_PREPARE_FROZEN: |
1da177e4 | 6441 | case CPU_DOWN_PREPARE: |
8bb78442 | 6442 | case CPU_DOWN_PREPARE_FROZEN: |
1a20ff27 | 6443 | detach_destroy_domains(&cpu_online_map); |
1da177e4 LT |
6444 | return NOTIFY_OK; |
6445 | ||
6446 | case CPU_UP_CANCELED: | |
8bb78442 | 6447 | case CPU_UP_CANCELED_FROZEN: |
1da177e4 | 6448 | case CPU_DOWN_FAILED: |
8bb78442 | 6449 | case CPU_DOWN_FAILED_FROZEN: |
1da177e4 | 6450 | case CPU_ONLINE: |
8bb78442 | 6451 | case CPU_ONLINE_FROZEN: |
1da177e4 | 6452 | case CPU_DEAD: |
8bb78442 | 6453 | case CPU_DEAD_FROZEN: |
1da177e4 LT |
6454 | /* |
6455 | * Fall through and re-initialise the domains. | |
6456 | */ | |
6457 | break; | |
6458 | default: | |
6459 | return NOTIFY_DONE; | |
6460 | } | |
6461 | ||
6462 | /* The hotplug lock is already held by cpu_up/cpu_down */ | |
1a20ff27 | 6463 | arch_init_sched_domains(&cpu_online_map); |
1da177e4 LT |
6464 | |
6465 | return NOTIFY_OK; | |
6466 | } | |
1da177e4 LT |
6467 | |
6468 | void __init sched_init_smp(void) | |
6469 | { | |
5c1e1767 NP |
6470 | cpumask_t non_isolated_cpus; |
6471 | ||
5be9361c | 6472 | mutex_lock(&sched_hotcpu_mutex); |
1a20ff27 | 6473 | arch_init_sched_domains(&cpu_online_map); |
e5e5673f | 6474 | cpus_andnot(non_isolated_cpus, cpu_possible_map, cpu_isolated_map); |
5c1e1767 NP |
6475 | if (cpus_empty(non_isolated_cpus)) |
6476 | cpu_set(smp_processor_id(), non_isolated_cpus); | |
5be9361c | 6477 | mutex_unlock(&sched_hotcpu_mutex); |
1da177e4 LT |
6478 | /* XXX: Theoretical race here - CPU may be hotplugged now */ |
6479 | hotcpu_notifier(update_sched_domains, 0); | |
5c1e1767 | 6480 | |
e692ab53 NP |
6481 | init_sched_domain_sysctl(); |
6482 | ||
5c1e1767 NP |
6483 | /* Move init over to a non-isolated CPU */ |
6484 | if (set_cpus_allowed(current, non_isolated_cpus) < 0) | |
6485 | BUG(); | |
dd41f596 | 6486 | sched_init_granularity(); |
1da177e4 LT |
6487 | } |
6488 | #else | |
6489 | void __init sched_init_smp(void) | |
6490 | { | |
dd41f596 | 6491 | sched_init_granularity(); |
1da177e4 LT |
6492 | } |
6493 | #endif /* CONFIG_SMP */ | |
6494 | ||
6495 | int in_sched_functions(unsigned long addr) | |
6496 | { | |
6497 | /* Linker adds these: start and end of __sched functions */ | |
6498 | extern char __sched_text_start[], __sched_text_end[]; | |
48f24c4d | 6499 | |
1da177e4 LT |
6500 | return in_lock_functions(addr) || |
6501 | (addr >= (unsigned long)__sched_text_start | |
6502 | && addr < (unsigned long)__sched_text_end); | |
6503 | } | |
6504 | ||
dd41f596 IM |
6505 | static inline void init_cfs_rq(struct cfs_rq *cfs_rq, struct rq *rq) |
6506 | { | |
6507 | cfs_rq->tasks_timeline = RB_ROOT; | |
6508 | cfs_rq->fair_clock = 1; | |
6509 | #ifdef CONFIG_FAIR_GROUP_SCHED | |
6510 | cfs_rq->rq = rq; | |
6511 | #endif | |
6512 | } | |
6513 | ||
1da177e4 LT |
6514 | void __init sched_init(void) |
6515 | { | |
dd41f596 | 6516 | u64 now = sched_clock(); |
476f3534 | 6517 | int highest_cpu = 0; |
dd41f596 IM |
6518 | int i, j; |
6519 | ||
6520 | /* | |
6521 | * Link up the scheduling class hierarchy: | |
6522 | */ | |
6523 | rt_sched_class.next = &fair_sched_class; | |
6524 | fair_sched_class.next = &idle_sched_class; | |
6525 | idle_sched_class.next = NULL; | |
1da177e4 | 6526 | |
0a945022 | 6527 | for_each_possible_cpu(i) { |
dd41f596 | 6528 | struct rt_prio_array *array; |
70b97a7f | 6529 | struct rq *rq; |
1da177e4 LT |
6530 | |
6531 | rq = cpu_rq(i); | |
6532 | spin_lock_init(&rq->lock); | |
fcb99371 | 6533 | lockdep_set_class(&rq->lock, &rq->rq_lock_key); |
7897986b | 6534 | rq->nr_running = 0; |
dd41f596 IM |
6535 | rq->clock = 1; |
6536 | init_cfs_rq(&rq->cfs, rq); | |
6537 | #ifdef CONFIG_FAIR_GROUP_SCHED | |
6538 | INIT_LIST_HEAD(&rq->leaf_cfs_rq_list); | |
6539 | list_add(&rq->cfs.leaf_cfs_rq_list, &rq->leaf_cfs_rq_list); | |
6540 | #endif | |
6541 | rq->ls.load_update_last = now; | |
6542 | rq->ls.load_update_start = now; | |
1da177e4 | 6543 | |
dd41f596 IM |
6544 | for (j = 0; j < CPU_LOAD_IDX_MAX; j++) |
6545 | rq->cpu_load[j] = 0; | |
1da177e4 | 6546 | #ifdef CONFIG_SMP |
41c7ce9a | 6547 | rq->sd = NULL; |
1da177e4 | 6548 | rq->active_balance = 0; |
dd41f596 | 6549 | rq->next_balance = jiffies; |
1da177e4 | 6550 | rq->push_cpu = 0; |
0a2966b4 | 6551 | rq->cpu = i; |
1da177e4 LT |
6552 | rq->migration_thread = NULL; |
6553 | INIT_LIST_HEAD(&rq->migration_queue); | |
6554 | #endif | |
6555 | atomic_set(&rq->nr_iowait, 0); | |
6556 | ||
dd41f596 IM |
6557 | array = &rq->rt.active; |
6558 | for (j = 0; j < MAX_RT_PRIO; j++) { | |
6559 | INIT_LIST_HEAD(array->queue + j); | |
6560 | __clear_bit(j, array->bitmap); | |
1da177e4 | 6561 | } |
476f3534 | 6562 | highest_cpu = i; |
dd41f596 IM |
6563 | /* delimiter for bitsearch: */ |
6564 | __set_bit(MAX_RT_PRIO, array->bitmap); | |
1da177e4 LT |
6565 | } |
6566 | ||
2dd73a4f | 6567 | set_load_weight(&init_task); |
b50f60ce | 6568 | |
e107be36 AK |
6569 | #ifdef CONFIG_PREEMPT_NOTIFIERS |
6570 | INIT_HLIST_HEAD(&init_task.preempt_notifiers); | |
6571 | #endif | |
6572 | ||
c9819f45 | 6573 | #ifdef CONFIG_SMP |
476f3534 | 6574 | nr_cpu_ids = highest_cpu + 1; |
c9819f45 CL |
6575 | open_softirq(SCHED_SOFTIRQ, run_rebalance_domains, NULL); |
6576 | #endif | |
6577 | ||
b50f60ce HC |
6578 | #ifdef CONFIG_RT_MUTEXES |
6579 | plist_head_init(&init_task.pi_waiters, &init_task.pi_lock); | |
6580 | #endif | |
6581 | ||
1da177e4 LT |
6582 | /* |
6583 | * The boot idle thread does lazy MMU switching as well: | |
6584 | */ | |
6585 | atomic_inc(&init_mm.mm_count); | |
6586 | enter_lazy_tlb(&init_mm, current); | |
6587 | ||
6588 | /* | |
6589 | * Make us the idle thread. Technically, schedule() should not be | |
6590 | * called from this thread, however somewhere below it might be, | |
6591 | * but because we are the idle thread, we just pick up running again | |
6592 | * when this runqueue becomes "idle". | |
6593 | */ | |
6594 | init_idle(current, smp_processor_id()); | |
dd41f596 IM |
6595 | /* |
6596 | * During early bootup we pretend to be a normal task: | |
6597 | */ | |
6598 | current->sched_class = &fair_sched_class; | |
1da177e4 LT |
6599 | } |
6600 | ||
6601 | #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP | |
6602 | void __might_sleep(char *file, int line) | |
6603 | { | |
48f24c4d | 6604 | #ifdef in_atomic |
1da177e4 LT |
6605 | static unsigned long prev_jiffy; /* ratelimiting */ |
6606 | ||
6607 | if ((in_atomic() || irqs_disabled()) && | |
6608 | system_state == SYSTEM_RUNNING && !oops_in_progress) { | |
6609 | if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy) | |
6610 | return; | |
6611 | prev_jiffy = jiffies; | |
91368d73 | 6612 | printk(KERN_ERR "BUG: sleeping function called from invalid" |
1da177e4 LT |
6613 | " context at %s:%d\n", file, line); |
6614 | printk("in_atomic():%d, irqs_disabled():%d\n", | |
6615 | in_atomic(), irqs_disabled()); | |
a4c410f0 | 6616 | debug_show_held_locks(current); |
3117df04 IM |
6617 | if (irqs_disabled()) |
6618 | print_irqtrace_events(current); | |
1da177e4 LT |
6619 | dump_stack(); |
6620 | } | |
6621 | #endif | |
6622 | } | |
6623 | EXPORT_SYMBOL(__might_sleep); | |
6624 | #endif | |
6625 | ||
6626 | #ifdef CONFIG_MAGIC_SYSRQ | |
6627 | void normalize_rt_tasks(void) | |
6628 | { | |
a0f98a1c | 6629 | struct task_struct *g, *p; |
1da177e4 | 6630 | unsigned long flags; |
70b97a7f | 6631 | struct rq *rq; |
dd41f596 | 6632 | int on_rq; |
1da177e4 LT |
6633 | |
6634 | read_lock_irq(&tasklist_lock); | |
a0f98a1c | 6635 | do_each_thread(g, p) { |
dd41f596 IM |
6636 | p->se.fair_key = 0; |
6637 | p->se.wait_runtime = 0; | |
6cfb0d5d | 6638 | p->se.exec_start = 0; |
dd41f596 | 6639 | p->se.wait_start_fair = 0; |
6cfb0d5d IM |
6640 | p->se.sleep_start_fair = 0; |
6641 | #ifdef CONFIG_SCHEDSTATS | |
dd41f596 | 6642 | p->se.wait_start = 0; |
dd41f596 | 6643 | p->se.sleep_start = 0; |
dd41f596 | 6644 | p->se.block_start = 0; |
6cfb0d5d | 6645 | #endif |
dd41f596 IM |
6646 | task_rq(p)->cfs.fair_clock = 0; |
6647 | task_rq(p)->clock = 0; | |
6648 | ||
6649 | if (!rt_task(p)) { | |
6650 | /* | |
6651 | * Renice negative nice level userspace | |
6652 | * tasks back to 0: | |
6653 | */ | |
6654 | if (TASK_NICE(p) < 0 && p->mm) | |
6655 | set_user_nice(p, 0); | |
1da177e4 | 6656 | continue; |
dd41f596 | 6657 | } |
1da177e4 | 6658 | |
b29739f9 IM |
6659 | spin_lock_irqsave(&p->pi_lock, flags); |
6660 | rq = __task_rq_lock(p); | |
dd41f596 IM |
6661 | #ifdef CONFIG_SMP |
6662 | /* | |
6663 | * Do not touch the migration thread: | |
6664 | */ | |
6665 | if (p == rq->migration_thread) | |
6666 | goto out_unlock; | |
6667 | #endif | |
1da177e4 | 6668 | |
2daa3577 | 6669 | update_rq_clock(rq); |
dd41f596 | 6670 | on_rq = p->se.on_rq; |
2daa3577 IM |
6671 | if (on_rq) |
6672 | deactivate_task(rq, p, 0); | |
dd41f596 IM |
6673 | __setscheduler(rq, p, SCHED_NORMAL, 0); |
6674 | if (on_rq) { | |
2daa3577 | 6675 | activate_task(rq, p, 0); |
1da177e4 LT |
6676 | resched_task(rq->curr); |
6677 | } | |
dd41f596 IM |
6678 | #ifdef CONFIG_SMP |
6679 | out_unlock: | |
6680 | #endif | |
b29739f9 IM |
6681 | __task_rq_unlock(rq); |
6682 | spin_unlock_irqrestore(&p->pi_lock, flags); | |
a0f98a1c IM |
6683 | } while_each_thread(g, p); |
6684 | ||
1da177e4 LT |
6685 | read_unlock_irq(&tasklist_lock); |
6686 | } | |
6687 | ||
6688 | #endif /* CONFIG_MAGIC_SYSRQ */ | |
1df5c10a LT |
6689 | |
6690 | #ifdef CONFIG_IA64 | |
6691 | /* | |
6692 | * These functions are only useful for the IA64 MCA handling. | |
6693 | * | |
6694 | * They can only be called when the whole system has been | |
6695 | * stopped - every CPU needs to be quiescent, and no scheduling | |
6696 | * activity can take place. Using them for anything else would | |
6697 | * be a serious bug, and as a result, they aren't even visible | |
6698 | * under any other configuration. | |
6699 | */ | |
6700 | ||
6701 | /** | |
6702 | * curr_task - return the current task for a given cpu. | |
6703 | * @cpu: the processor in question. | |
6704 | * | |
6705 | * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! | |
6706 | */ | |
36c8b586 | 6707 | struct task_struct *curr_task(int cpu) |
1df5c10a LT |
6708 | { |
6709 | return cpu_curr(cpu); | |
6710 | } | |
6711 | ||
6712 | /** | |
6713 | * set_curr_task - set the current task for a given cpu. | |
6714 | * @cpu: the processor in question. | |
6715 | * @p: the task pointer to set. | |
6716 | * | |
6717 | * Description: This function must only be used when non-maskable interrupts | |
6718 | * are serviced on a separate stack. It allows the architecture to switch the | |
6719 | * notion of the current task on a cpu in a non-blocking manner. This function | |
6720 | * must be called with all CPU's synchronized, and interrupts disabled, the | |
6721 | * and caller must save the original value of the current task (see | |
6722 | * curr_task() above) and restore that value before reenabling interrupts and | |
6723 | * re-starting the system. | |
6724 | * | |
6725 | * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! | |
6726 | */ | |
36c8b586 | 6727 | void set_curr_task(int cpu, struct task_struct *p) |
1df5c10a LT |
6728 | { |
6729 | cpu_curr(cpu) = p; | |
6730 | } | |
6731 | ||
6732 | #endif |