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> | |
b488893a | 47 | #include <linux/pid_namespace.h> |
1da177e4 LT |
48 | #include <linux/smp.h> |
49 | #include <linux/threads.h> | |
50 | #include <linux/timer.h> | |
51 | #include <linux/rcupdate.h> | |
52 | #include <linux/cpu.h> | |
53 | #include <linux/cpuset.h> | |
54 | #include <linux/percpu.h> | |
55 | #include <linux/kthread.h> | |
56 | #include <linux/seq_file.h> | |
e692ab53 | 57 | #include <linux/sysctl.h> |
1da177e4 LT |
58 | #include <linux/syscalls.h> |
59 | #include <linux/times.h> | |
8f0ab514 | 60 | #include <linux/tsacct_kern.h> |
c6fd91f0 | 61 | #include <linux/kprobes.h> |
0ff92245 | 62 | #include <linux/delayacct.h> |
5517d86b | 63 | #include <linux/reciprocal_div.h> |
dff06c15 | 64 | #include <linux/unistd.h> |
f5ff8422 | 65 | #include <linux/pagemap.h> |
1da177e4 | 66 | |
5517d86b | 67 | #include <asm/tlb.h> |
838225b4 | 68 | #include <asm/irq_regs.h> |
1da177e4 | 69 | |
b035b6de AD |
70 | /* |
71 | * Scheduler clock - returns current time in nanosec units. | |
72 | * This is default implementation. | |
73 | * Architectures and sub-architectures can override this. | |
74 | */ | |
75 | unsigned long long __attribute__((weak)) sched_clock(void) | |
76 | { | |
d6322faf | 77 | return (unsigned long long)jiffies * (NSEC_PER_SEC / HZ); |
b035b6de AD |
78 | } |
79 | ||
1da177e4 LT |
80 | /* |
81 | * Convert user-nice values [ -20 ... 0 ... 19 ] | |
82 | * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ], | |
83 | * and back. | |
84 | */ | |
85 | #define NICE_TO_PRIO(nice) (MAX_RT_PRIO + (nice) + 20) | |
86 | #define PRIO_TO_NICE(prio) ((prio) - MAX_RT_PRIO - 20) | |
87 | #define TASK_NICE(p) PRIO_TO_NICE((p)->static_prio) | |
88 | ||
89 | /* | |
90 | * 'User priority' is the nice value converted to something we | |
91 | * can work with better when scaling various scheduler parameters, | |
92 | * it's a [ 0 ... 39 ] range. | |
93 | */ | |
94 | #define USER_PRIO(p) ((p)-MAX_RT_PRIO) | |
95 | #define TASK_USER_PRIO(p) USER_PRIO((p)->static_prio) | |
96 | #define MAX_USER_PRIO (USER_PRIO(MAX_PRIO)) | |
97 | ||
98 | /* | |
99 | * Some helpers for converting nanosecond timing to jiffy resolution | |
100 | */ | |
d6322faf ED |
101 | #define NS_TO_JIFFIES(TIME) ((unsigned long)(TIME) / (NSEC_PER_SEC / HZ)) |
102 | #define JIFFIES_TO_NS(TIME) ((TIME) * (NSEC_PER_SEC / HZ)) | |
1da177e4 | 103 | |
6aa645ea IM |
104 | #define NICE_0_LOAD SCHED_LOAD_SCALE |
105 | #define NICE_0_SHIFT SCHED_LOAD_SHIFT | |
106 | ||
1da177e4 LT |
107 | /* |
108 | * These are the 'tuning knobs' of the scheduler: | |
109 | * | |
a4ec24b4 | 110 | * default timeslice is 100 msecs (used only for SCHED_RR tasks). |
1da177e4 LT |
111 | * Timeslices get refilled after they expire. |
112 | */ | |
1da177e4 | 113 | #define DEF_TIMESLICE (100 * HZ / 1000) |
2dd73a4f | 114 | |
5517d86b ED |
115 | #ifdef CONFIG_SMP |
116 | /* | |
117 | * Divide a load by a sched group cpu_power : (load / sg->__cpu_power) | |
118 | * Since cpu_power is a 'constant', we can use a reciprocal divide. | |
119 | */ | |
120 | static inline u32 sg_div_cpu_power(const struct sched_group *sg, u32 load) | |
121 | { | |
122 | return reciprocal_divide(load, sg->reciprocal_cpu_power); | |
123 | } | |
124 | ||
125 | /* | |
126 | * Each time a sched group cpu_power is changed, | |
127 | * we must compute its reciprocal value | |
128 | */ | |
129 | static inline void sg_inc_cpu_power(struct sched_group *sg, u32 val) | |
130 | { | |
131 | sg->__cpu_power += val; | |
132 | sg->reciprocal_cpu_power = reciprocal_value(sg->__cpu_power); | |
133 | } | |
134 | #endif | |
135 | ||
e05606d3 IM |
136 | static inline int rt_policy(int policy) |
137 | { | |
138 | if (unlikely(policy == SCHED_FIFO) || unlikely(policy == SCHED_RR)) | |
139 | return 1; | |
140 | return 0; | |
141 | } | |
142 | ||
143 | static inline int task_has_rt_policy(struct task_struct *p) | |
144 | { | |
145 | return rt_policy(p->policy); | |
146 | } | |
147 | ||
1da177e4 | 148 | /* |
6aa645ea | 149 | * This is the priority-queue data structure of the RT scheduling class: |
1da177e4 | 150 | */ |
6aa645ea IM |
151 | struct rt_prio_array { |
152 | DECLARE_BITMAP(bitmap, MAX_RT_PRIO+1); /* include 1 bit for delimiter */ | |
153 | struct list_head queue[MAX_RT_PRIO]; | |
154 | }; | |
155 | ||
29f59db3 SV |
156 | #ifdef CONFIG_FAIR_GROUP_SCHED |
157 | ||
68318b8e SV |
158 | #include <linux/cgroup.h> |
159 | ||
29f59db3 SV |
160 | struct cfs_rq; |
161 | ||
162 | /* task group related information */ | |
4cf86d77 | 163 | struct task_group { |
68318b8e SV |
164 | #ifdef CONFIG_FAIR_CGROUP_SCHED |
165 | struct cgroup_subsys_state css; | |
166 | #endif | |
29f59db3 SV |
167 | /* schedulable entities of this group on each cpu */ |
168 | struct sched_entity **se; | |
169 | /* runqueue "owned" by this group on each cpu */ | |
170 | struct cfs_rq **cfs_rq; | |
171 | unsigned long shares; | |
5cb350ba DG |
172 | /* spinlock to serialize modification to shares */ |
173 | spinlock_t lock; | |
ae8393e5 | 174 | struct rcu_head rcu; |
29f59db3 SV |
175 | }; |
176 | ||
177 | /* Default task group's sched entity on each cpu */ | |
178 | static DEFINE_PER_CPU(struct sched_entity, init_sched_entity); | |
179 | /* Default task group's cfs_rq on each cpu */ | |
180 | static DEFINE_PER_CPU(struct cfs_rq, init_cfs_rq) ____cacheline_aligned_in_smp; | |
181 | ||
9b5b7751 SV |
182 | static struct sched_entity *init_sched_entity_p[NR_CPUS]; |
183 | static struct cfs_rq *init_cfs_rq_p[NR_CPUS]; | |
29f59db3 SV |
184 | |
185 | /* Default task group. | |
3a252015 | 186 | * Every task in system belong to this group at bootup. |
29f59db3 | 187 | */ |
4cf86d77 | 188 | struct task_group init_task_group = { |
3a252015 IM |
189 | .se = init_sched_entity_p, |
190 | .cfs_rq = init_cfs_rq_p, | |
191 | }; | |
9b5b7751 | 192 | |
24e377a8 | 193 | #ifdef CONFIG_FAIR_USER_SCHED |
3a252015 | 194 | # define INIT_TASK_GRP_LOAD 2*NICE_0_LOAD |
24e377a8 | 195 | #else |
3a252015 | 196 | # define INIT_TASK_GRP_LOAD NICE_0_LOAD |
24e377a8 SV |
197 | #endif |
198 | ||
4cf86d77 | 199 | static int init_task_group_load = INIT_TASK_GRP_LOAD; |
29f59db3 SV |
200 | |
201 | /* return group to which a task belongs */ | |
4cf86d77 | 202 | static inline struct task_group *task_group(struct task_struct *p) |
29f59db3 | 203 | { |
4cf86d77 | 204 | struct task_group *tg; |
9b5b7751 | 205 | |
24e377a8 SV |
206 | #ifdef CONFIG_FAIR_USER_SCHED |
207 | tg = p->user->tg; | |
68318b8e SV |
208 | #elif defined(CONFIG_FAIR_CGROUP_SCHED) |
209 | tg = container_of(task_subsys_state(p, cpu_cgroup_subsys_id), | |
210 | struct task_group, css); | |
24e377a8 | 211 | #else |
41a2d6cf | 212 | tg = &init_task_group; |
24e377a8 | 213 | #endif |
9b5b7751 | 214 | return tg; |
29f59db3 SV |
215 | } |
216 | ||
217 | /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */ | |
ce96b5ac | 218 | static inline void set_task_cfs_rq(struct task_struct *p, unsigned int cpu) |
29f59db3 | 219 | { |
ce96b5ac DA |
220 | p->se.cfs_rq = task_group(p)->cfs_rq[cpu]; |
221 | p->se.parent = task_group(p)->se[cpu]; | |
29f59db3 SV |
222 | } |
223 | ||
224 | #else | |
225 | ||
ce96b5ac | 226 | static inline void set_task_cfs_rq(struct task_struct *p, unsigned int cpu) { } |
29f59db3 SV |
227 | |
228 | #endif /* CONFIG_FAIR_GROUP_SCHED */ | |
229 | ||
6aa645ea IM |
230 | /* CFS-related fields in a runqueue */ |
231 | struct cfs_rq { | |
232 | struct load_weight load; | |
233 | unsigned long nr_running; | |
234 | ||
6aa645ea | 235 | u64 exec_clock; |
e9acbff6 | 236 | u64 min_vruntime; |
6aa645ea IM |
237 | |
238 | struct rb_root tasks_timeline; | |
239 | struct rb_node *rb_leftmost; | |
240 | struct rb_node *rb_load_balance_curr; | |
6aa645ea IM |
241 | /* 'curr' points to currently running entity on this cfs_rq. |
242 | * It is set to NULL otherwise (i.e when none are currently running). | |
243 | */ | |
244 | struct sched_entity *curr; | |
ddc97297 PZ |
245 | |
246 | unsigned long nr_spread_over; | |
247 | ||
62160e3f | 248 | #ifdef CONFIG_FAIR_GROUP_SCHED |
6aa645ea IM |
249 | struct rq *rq; /* cpu runqueue to which this cfs_rq is attached */ |
250 | ||
41a2d6cf IM |
251 | /* |
252 | * leaf cfs_rqs are those that hold tasks (lowest schedulable entity in | |
6aa645ea IM |
253 | * a hierarchy). Non-leaf lrqs hold other higher schedulable entities |
254 | * (like users, containers etc.) | |
255 | * | |
256 | * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This | |
257 | * list is used during load balance. | |
258 | */ | |
41a2d6cf IM |
259 | struct list_head leaf_cfs_rq_list; |
260 | struct task_group *tg; /* group that "owns" this runqueue */ | |
6aa645ea IM |
261 | #endif |
262 | }; | |
1da177e4 | 263 | |
6aa645ea IM |
264 | /* Real-Time classes' related field in a runqueue: */ |
265 | struct rt_rq { | |
266 | struct rt_prio_array active; | |
267 | int rt_load_balance_idx; | |
268 | struct list_head *rt_load_balance_head, *rt_load_balance_curr; | |
269 | }; | |
270 | ||
1da177e4 LT |
271 | /* |
272 | * This is the main, per-CPU runqueue data structure. | |
273 | * | |
274 | * Locking rule: those places that want to lock multiple runqueues | |
275 | * (such as the load balancing or the thread migration code), lock | |
276 | * acquire operations must be ordered by ascending &runqueue. | |
277 | */ | |
70b97a7f | 278 | struct rq { |
d8016491 IM |
279 | /* runqueue lock: */ |
280 | spinlock_t lock; | |
1da177e4 LT |
281 | |
282 | /* | |
283 | * nr_running and cpu_load should be in the same cacheline because | |
284 | * remote CPUs use both these fields when doing load calculation. | |
285 | */ | |
286 | unsigned long nr_running; | |
6aa645ea IM |
287 | #define CPU_LOAD_IDX_MAX 5 |
288 | unsigned long cpu_load[CPU_LOAD_IDX_MAX]; | |
bdecea3a | 289 | unsigned char idle_at_tick; |
46cb4b7c SS |
290 | #ifdef CONFIG_NO_HZ |
291 | unsigned char in_nohz_recently; | |
292 | #endif | |
d8016491 IM |
293 | /* capture load from *all* tasks on this cpu: */ |
294 | struct load_weight load; | |
6aa645ea IM |
295 | unsigned long nr_load_updates; |
296 | u64 nr_switches; | |
297 | ||
298 | struct cfs_rq cfs; | |
299 | #ifdef CONFIG_FAIR_GROUP_SCHED | |
d8016491 IM |
300 | /* list of leaf cfs_rq on this cpu: */ |
301 | struct list_head leaf_cfs_rq_list; | |
1da177e4 | 302 | #endif |
41a2d6cf | 303 | struct rt_rq rt; |
1da177e4 LT |
304 | |
305 | /* | |
306 | * This is part of a global counter where only the total sum | |
307 | * over all CPUs matters. A task can increase this counter on | |
308 | * one CPU and if it got migrated afterwards it may decrease | |
309 | * it on another CPU. Always updated under the runqueue lock: | |
310 | */ | |
311 | unsigned long nr_uninterruptible; | |
312 | ||
36c8b586 | 313 | struct task_struct *curr, *idle; |
c9819f45 | 314 | unsigned long next_balance; |
1da177e4 | 315 | struct mm_struct *prev_mm; |
6aa645ea | 316 | |
6aa645ea IM |
317 | u64 clock, prev_clock_raw; |
318 | s64 clock_max_delta; | |
319 | ||
320 | unsigned int clock_warps, clock_overflows; | |
2aa44d05 IM |
321 | u64 idle_clock; |
322 | unsigned int clock_deep_idle_events; | |
529c7726 | 323 | u64 tick_timestamp; |
6aa645ea | 324 | |
1da177e4 LT |
325 | atomic_t nr_iowait; |
326 | ||
327 | #ifdef CONFIG_SMP | |
328 | struct sched_domain *sd; | |
329 | ||
330 | /* For active balancing */ | |
331 | int active_balance; | |
332 | int push_cpu; | |
d8016491 IM |
333 | /* cpu of this runqueue: */ |
334 | int cpu; | |
1da177e4 | 335 | |
36c8b586 | 336 | struct task_struct *migration_thread; |
1da177e4 LT |
337 | struct list_head migration_queue; |
338 | #endif | |
339 | ||
340 | #ifdef CONFIG_SCHEDSTATS | |
341 | /* latency stats */ | |
342 | struct sched_info rq_sched_info; | |
343 | ||
344 | /* sys_sched_yield() stats */ | |
480b9434 KC |
345 | unsigned int yld_exp_empty; |
346 | unsigned int yld_act_empty; | |
347 | unsigned int yld_both_empty; | |
348 | unsigned int yld_count; | |
1da177e4 LT |
349 | |
350 | /* schedule() stats */ | |
480b9434 KC |
351 | unsigned int sched_switch; |
352 | unsigned int sched_count; | |
353 | unsigned int sched_goidle; | |
1da177e4 LT |
354 | |
355 | /* try_to_wake_up() stats */ | |
480b9434 KC |
356 | unsigned int ttwu_count; |
357 | unsigned int ttwu_local; | |
b8efb561 IM |
358 | |
359 | /* BKL stats */ | |
480b9434 | 360 | unsigned int bkl_count; |
1da177e4 | 361 | #endif |
fcb99371 | 362 | struct lock_class_key rq_lock_key; |
1da177e4 LT |
363 | }; |
364 | ||
f34e3b61 | 365 | static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues); |
5be9361c | 366 | static DEFINE_MUTEX(sched_hotcpu_mutex); |
1da177e4 | 367 | |
dd41f596 IM |
368 | static inline void check_preempt_curr(struct rq *rq, struct task_struct *p) |
369 | { | |
370 | rq->curr->sched_class->check_preempt_curr(rq, p); | |
371 | } | |
372 | ||
0a2966b4 CL |
373 | static inline int cpu_of(struct rq *rq) |
374 | { | |
375 | #ifdef CONFIG_SMP | |
376 | return rq->cpu; | |
377 | #else | |
378 | return 0; | |
379 | #endif | |
380 | } | |
381 | ||
20d315d4 | 382 | /* |
b04a0f4c IM |
383 | * Update the per-runqueue clock, as finegrained as the platform can give |
384 | * us, but without assuming monotonicity, etc.: | |
20d315d4 | 385 | */ |
b04a0f4c | 386 | static void __update_rq_clock(struct rq *rq) |
20d315d4 IM |
387 | { |
388 | u64 prev_raw = rq->prev_clock_raw; | |
389 | u64 now = sched_clock(); | |
390 | s64 delta = now - prev_raw; | |
391 | u64 clock = rq->clock; | |
392 | ||
b04a0f4c IM |
393 | #ifdef CONFIG_SCHED_DEBUG |
394 | WARN_ON_ONCE(cpu_of(rq) != smp_processor_id()); | |
395 | #endif | |
20d315d4 IM |
396 | /* |
397 | * Protect against sched_clock() occasionally going backwards: | |
398 | */ | |
399 | if (unlikely(delta < 0)) { | |
400 | clock++; | |
401 | rq->clock_warps++; | |
402 | } else { | |
403 | /* | |
404 | * Catch too large forward jumps too: | |
405 | */ | |
529c7726 IM |
406 | if (unlikely(clock + delta > rq->tick_timestamp + TICK_NSEC)) { |
407 | if (clock < rq->tick_timestamp + TICK_NSEC) | |
408 | clock = rq->tick_timestamp + TICK_NSEC; | |
409 | else | |
410 | clock++; | |
20d315d4 IM |
411 | rq->clock_overflows++; |
412 | } else { | |
413 | if (unlikely(delta > rq->clock_max_delta)) | |
414 | rq->clock_max_delta = delta; | |
415 | clock += delta; | |
416 | } | |
417 | } | |
418 | ||
419 | rq->prev_clock_raw = now; | |
420 | rq->clock = clock; | |
b04a0f4c | 421 | } |
20d315d4 | 422 | |
b04a0f4c IM |
423 | static void update_rq_clock(struct rq *rq) |
424 | { | |
425 | if (likely(smp_processor_id() == cpu_of(rq))) | |
426 | __update_rq_clock(rq); | |
20d315d4 IM |
427 | } |
428 | ||
674311d5 NP |
429 | /* |
430 | * The domain tree (rq->sd) is protected by RCU's quiescent state transition. | |
1a20ff27 | 431 | * See detach_destroy_domains: synchronize_sched for details. |
674311d5 NP |
432 | * |
433 | * The domain tree of any CPU may only be accessed from within | |
434 | * preempt-disabled sections. | |
435 | */ | |
48f24c4d IM |
436 | #define for_each_domain(cpu, __sd) \ |
437 | for (__sd = rcu_dereference(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent) | |
1da177e4 LT |
438 | |
439 | #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu))) | |
440 | #define this_rq() (&__get_cpu_var(runqueues)) | |
441 | #define task_rq(p) cpu_rq(task_cpu(p)) | |
442 | #define cpu_curr(cpu) (cpu_rq(cpu)->curr) | |
443 | ||
bf5c91ba IM |
444 | /* |
445 | * Tunables that become constants when CONFIG_SCHED_DEBUG is off: | |
446 | */ | |
447 | #ifdef CONFIG_SCHED_DEBUG | |
448 | # define const_debug __read_mostly | |
449 | #else | |
450 | # define const_debug static const | |
451 | #endif | |
452 | ||
453 | /* | |
454 | * Debugging: various feature bits | |
455 | */ | |
456 | enum { | |
bbdba7c0 | 457 | SCHED_FEAT_NEW_FAIR_SLEEPERS = 1, |
9612633a IM |
458 | SCHED_FEAT_WAKEUP_PREEMPT = 2, |
459 | SCHED_FEAT_START_DEBIT = 4, | |
41a2d6cf IM |
460 | SCHED_FEAT_TREE_AVG = 8, |
461 | SCHED_FEAT_APPROX_AVG = 16, | |
bf5c91ba IM |
462 | }; |
463 | ||
464 | const_debug unsigned int sysctl_sched_features = | |
8401f775 | 465 | SCHED_FEAT_NEW_FAIR_SLEEPERS * 1 | |
9612633a | 466 | SCHED_FEAT_WAKEUP_PREEMPT * 1 | |
8401f775 IM |
467 | SCHED_FEAT_START_DEBIT * 1 | |
468 | SCHED_FEAT_TREE_AVG * 0 | | |
9612633a | 469 | SCHED_FEAT_APPROX_AVG * 0; |
bf5c91ba IM |
470 | |
471 | #define sched_feat(x) (sysctl_sched_features & SCHED_FEAT_##x) | |
472 | ||
b82d9fdd PZ |
473 | /* |
474 | * Number of tasks to iterate in a single balance run. | |
475 | * Limited because this is done with IRQs disabled. | |
476 | */ | |
477 | const_debug unsigned int sysctl_sched_nr_migrate = 32; | |
478 | ||
e436d800 IM |
479 | /* |
480 | * For kernel-internal use: high-speed (but slightly incorrect) per-cpu | |
481 | * clock constructed from sched_clock(): | |
482 | */ | |
483 | unsigned long long cpu_clock(int cpu) | |
484 | { | |
e436d800 IM |
485 | unsigned long long now; |
486 | unsigned long flags; | |
b04a0f4c | 487 | struct rq *rq; |
e436d800 | 488 | |
2cd4d0ea | 489 | local_irq_save(flags); |
b04a0f4c | 490 | rq = cpu_rq(cpu); |
8ced5f69 IM |
491 | /* |
492 | * Only call sched_clock() if the scheduler has already been | |
493 | * initialized (some code might call cpu_clock() very early): | |
494 | */ | |
495 | if (rq->idle) | |
496 | update_rq_clock(rq); | |
b04a0f4c | 497 | now = rq->clock; |
2cd4d0ea | 498 | local_irq_restore(flags); |
e436d800 IM |
499 | |
500 | return now; | |
501 | } | |
a58f6f25 | 502 | EXPORT_SYMBOL_GPL(cpu_clock); |
e436d800 | 503 | |
1da177e4 | 504 | #ifndef prepare_arch_switch |
4866cde0 NP |
505 | # define prepare_arch_switch(next) do { } while (0) |
506 | #endif | |
507 | #ifndef finish_arch_switch | |
508 | # define finish_arch_switch(prev) do { } while (0) | |
509 | #endif | |
510 | ||
511 | #ifndef __ARCH_WANT_UNLOCKED_CTXSW | |
70b97a7f | 512 | static inline int task_running(struct rq *rq, struct task_struct *p) |
4866cde0 NP |
513 | { |
514 | return rq->curr == p; | |
515 | } | |
516 | ||
70b97a7f | 517 | static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next) |
4866cde0 NP |
518 | { |
519 | } | |
520 | ||
70b97a7f | 521 | static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev) |
4866cde0 | 522 | { |
da04c035 IM |
523 | #ifdef CONFIG_DEBUG_SPINLOCK |
524 | /* this is a valid case when another task releases the spinlock */ | |
525 | rq->lock.owner = current; | |
526 | #endif | |
8a25d5de IM |
527 | /* |
528 | * If we are tracking spinlock dependencies then we have to | |
529 | * fix up the runqueue lock - which gets 'carried over' from | |
530 | * prev into current: | |
531 | */ | |
532 | spin_acquire(&rq->lock.dep_map, 0, 0, _THIS_IP_); | |
533 | ||
4866cde0 NP |
534 | spin_unlock_irq(&rq->lock); |
535 | } | |
536 | ||
537 | #else /* __ARCH_WANT_UNLOCKED_CTXSW */ | |
70b97a7f | 538 | static inline int task_running(struct rq *rq, struct task_struct *p) |
4866cde0 NP |
539 | { |
540 | #ifdef CONFIG_SMP | |
541 | return p->oncpu; | |
542 | #else | |
543 | return rq->curr == p; | |
544 | #endif | |
545 | } | |
546 | ||
70b97a7f | 547 | static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next) |
4866cde0 NP |
548 | { |
549 | #ifdef CONFIG_SMP | |
550 | /* | |
551 | * We can optimise this out completely for !SMP, because the | |
552 | * SMP rebalancing from interrupt is the only thing that cares | |
553 | * here. | |
554 | */ | |
555 | next->oncpu = 1; | |
556 | #endif | |
557 | #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW | |
558 | spin_unlock_irq(&rq->lock); | |
559 | #else | |
560 | spin_unlock(&rq->lock); | |
561 | #endif | |
562 | } | |
563 | ||
70b97a7f | 564 | static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev) |
4866cde0 NP |
565 | { |
566 | #ifdef CONFIG_SMP | |
567 | /* | |
568 | * After ->oncpu is cleared, the task can be moved to a different CPU. | |
569 | * We must ensure this doesn't happen until the switch is completely | |
570 | * finished. | |
571 | */ | |
572 | smp_wmb(); | |
573 | prev->oncpu = 0; | |
574 | #endif | |
575 | #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW | |
576 | local_irq_enable(); | |
1da177e4 | 577 | #endif |
4866cde0 NP |
578 | } |
579 | #endif /* __ARCH_WANT_UNLOCKED_CTXSW */ | |
1da177e4 | 580 | |
b29739f9 IM |
581 | /* |
582 | * __task_rq_lock - lock the runqueue a given task resides on. | |
583 | * Must be called interrupts disabled. | |
584 | */ | |
70b97a7f | 585 | static inline struct rq *__task_rq_lock(struct task_struct *p) |
b29739f9 IM |
586 | __acquires(rq->lock) |
587 | { | |
3a5c359a AK |
588 | for (;;) { |
589 | struct rq *rq = task_rq(p); | |
590 | spin_lock(&rq->lock); | |
591 | if (likely(rq == task_rq(p))) | |
592 | return rq; | |
b29739f9 | 593 | spin_unlock(&rq->lock); |
b29739f9 | 594 | } |
b29739f9 IM |
595 | } |
596 | ||
1da177e4 LT |
597 | /* |
598 | * task_rq_lock - lock the runqueue a given task resides on and disable | |
41a2d6cf | 599 | * interrupts. Note the ordering: we can safely lookup the task_rq without |
1da177e4 LT |
600 | * explicitly disabling preemption. |
601 | */ | |
70b97a7f | 602 | static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags) |
1da177e4 LT |
603 | __acquires(rq->lock) |
604 | { | |
70b97a7f | 605 | struct rq *rq; |
1da177e4 | 606 | |
3a5c359a AK |
607 | for (;;) { |
608 | local_irq_save(*flags); | |
609 | rq = task_rq(p); | |
610 | spin_lock(&rq->lock); | |
611 | if (likely(rq == task_rq(p))) | |
612 | return rq; | |
1da177e4 | 613 | spin_unlock_irqrestore(&rq->lock, *flags); |
1da177e4 | 614 | } |
1da177e4 LT |
615 | } |
616 | ||
a9957449 | 617 | static void __task_rq_unlock(struct rq *rq) |
b29739f9 IM |
618 | __releases(rq->lock) |
619 | { | |
620 | spin_unlock(&rq->lock); | |
621 | } | |
622 | ||
70b97a7f | 623 | static inline void task_rq_unlock(struct rq *rq, unsigned long *flags) |
1da177e4 LT |
624 | __releases(rq->lock) |
625 | { | |
626 | spin_unlock_irqrestore(&rq->lock, *flags); | |
627 | } | |
628 | ||
1da177e4 | 629 | /* |
cc2a73b5 | 630 | * this_rq_lock - lock this runqueue and disable interrupts. |
1da177e4 | 631 | */ |
a9957449 | 632 | static struct rq *this_rq_lock(void) |
1da177e4 LT |
633 | __acquires(rq->lock) |
634 | { | |
70b97a7f | 635 | struct rq *rq; |
1da177e4 LT |
636 | |
637 | local_irq_disable(); | |
638 | rq = this_rq(); | |
639 | spin_lock(&rq->lock); | |
640 | ||
641 | return rq; | |
642 | } | |
643 | ||
1b9f19c2 | 644 | /* |
2aa44d05 | 645 | * We are going deep-idle (irqs are disabled): |
1b9f19c2 | 646 | */ |
2aa44d05 | 647 | void sched_clock_idle_sleep_event(void) |
1b9f19c2 | 648 | { |
2aa44d05 IM |
649 | struct rq *rq = cpu_rq(smp_processor_id()); |
650 | ||
651 | spin_lock(&rq->lock); | |
652 | __update_rq_clock(rq); | |
653 | spin_unlock(&rq->lock); | |
654 | rq->clock_deep_idle_events++; | |
655 | } | |
656 | EXPORT_SYMBOL_GPL(sched_clock_idle_sleep_event); | |
657 | ||
658 | /* | |
659 | * We just idled delta nanoseconds (called with irqs disabled): | |
660 | */ | |
661 | void sched_clock_idle_wakeup_event(u64 delta_ns) | |
662 | { | |
663 | struct rq *rq = cpu_rq(smp_processor_id()); | |
664 | u64 now = sched_clock(); | |
1b9f19c2 | 665 | |
2aa44d05 IM |
666 | rq->idle_clock += delta_ns; |
667 | /* | |
668 | * Override the previous timestamp and ignore all | |
669 | * sched_clock() deltas that occured while we idled, | |
670 | * and use the PM-provided delta_ns to advance the | |
671 | * rq clock: | |
672 | */ | |
673 | spin_lock(&rq->lock); | |
674 | rq->prev_clock_raw = now; | |
675 | rq->clock += delta_ns; | |
676 | spin_unlock(&rq->lock); | |
1b9f19c2 | 677 | } |
2aa44d05 | 678 | EXPORT_SYMBOL_GPL(sched_clock_idle_wakeup_event); |
1b9f19c2 | 679 | |
c24d20db IM |
680 | /* |
681 | * resched_task - mark a task 'to be rescheduled now'. | |
682 | * | |
683 | * On UP this means the setting of the need_resched flag, on SMP it | |
684 | * might also involve a cross-CPU call to trigger the scheduler on | |
685 | * the target CPU. | |
686 | */ | |
687 | #ifdef CONFIG_SMP | |
688 | ||
689 | #ifndef tsk_is_polling | |
690 | #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG) | |
691 | #endif | |
692 | ||
693 | static void resched_task(struct task_struct *p) | |
694 | { | |
695 | int cpu; | |
696 | ||
697 | assert_spin_locked(&task_rq(p)->lock); | |
698 | ||
699 | if (unlikely(test_tsk_thread_flag(p, TIF_NEED_RESCHED))) | |
700 | return; | |
701 | ||
702 | set_tsk_thread_flag(p, TIF_NEED_RESCHED); | |
703 | ||
704 | cpu = task_cpu(p); | |
705 | if (cpu == smp_processor_id()) | |
706 | return; | |
707 | ||
708 | /* NEED_RESCHED must be visible before we test polling */ | |
709 | smp_mb(); | |
710 | if (!tsk_is_polling(p)) | |
711 | smp_send_reschedule(cpu); | |
712 | } | |
713 | ||
714 | static void resched_cpu(int cpu) | |
715 | { | |
716 | struct rq *rq = cpu_rq(cpu); | |
717 | unsigned long flags; | |
718 | ||
719 | if (!spin_trylock_irqsave(&rq->lock, flags)) | |
720 | return; | |
721 | resched_task(cpu_curr(cpu)); | |
722 | spin_unlock_irqrestore(&rq->lock, flags); | |
723 | } | |
724 | #else | |
725 | static inline void resched_task(struct task_struct *p) | |
726 | { | |
727 | assert_spin_locked(&task_rq(p)->lock); | |
728 | set_tsk_need_resched(p); | |
729 | } | |
730 | #endif | |
731 | ||
45bf76df IM |
732 | #if BITS_PER_LONG == 32 |
733 | # define WMULT_CONST (~0UL) | |
734 | #else | |
735 | # define WMULT_CONST (1UL << 32) | |
736 | #endif | |
737 | ||
738 | #define WMULT_SHIFT 32 | |
739 | ||
194081eb IM |
740 | /* |
741 | * Shift right and round: | |
742 | */ | |
cf2ab469 | 743 | #define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y)) |
194081eb | 744 | |
cb1c4fc9 | 745 | static unsigned long |
45bf76df IM |
746 | calc_delta_mine(unsigned long delta_exec, unsigned long weight, |
747 | struct load_weight *lw) | |
748 | { | |
749 | u64 tmp; | |
750 | ||
751 | if (unlikely(!lw->inv_weight)) | |
194081eb | 752 | lw->inv_weight = (WMULT_CONST - lw->weight/2) / lw->weight + 1; |
45bf76df IM |
753 | |
754 | tmp = (u64)delta_exec * weight; | |
755 | /* | |
756 | * Check whether we'd overflow the 64-bit multiplication: | |
757 | */ | |
194081eb | 758 | if (unlikely(tmp > WMULT_CONST)) |
cf2ab469 | 759 | tmp = SRR(SRR(tmp, WMULT_SHIFT/2) * lw->inv_weight, |
194081eb IM |
760 | WMULT_SHIFT/2); |
761 | else | |
cf2ab469 | 762 | tmp = SRR(tmp * lw->inv_weight, WMULT_SHIFT); |
45bf76df | 763 | |
ecf691da | 764 | return (unsigned long)min(tmp, (u64)(unsigned long)LONG_MAX); |
45bf76df IM |
765 | } |
766 | ||
767 | static inline unsigned long | |
768 | calc_delta_fair(unsigned long delta_exec, struct load_weight *lw) | |
769 | { | |
770 | return calc_delta_mine(delta_exec, NICE_0_LOAD, lw); | |
771 | } | |
772 | ||
1091985b | 773 | static inline void update_load_add(struct load_weight *lw, unsigned long inc) |
45bf76df IM |
774 | { |
775 | lw->weight += inc; | |
45bf76df IM |
776 | } |
777 | ||
1091985b | 778 | static inline void update_load_sub(struct load_weight *lw, unsigned long dec) |
45bf76df IM |
779 | { |
780 | lw->weight -= dec; | |
45bf76df IM |
781 | } |
782 | ||
2dd73a4f PW |
783 | /* |
784 | * To aid in avoiding the subversion of "niceness" due to uneven distribution | |
785 | * of tasks with abnormal "nice" values across CPUs the contribution that | |
786 | * each task makes to its run queue's load is weighted according to its | |
41a2d6cf | 787 | * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a |
2dd73a4f PW |
788 | * scaled version of the new time slice allocation that they receive on time |
789 | * slice expiry etc. | |
790 | */ | |
791 | ||
dd41f596 IM |
792 | #define WEIGHT_IDLEPRIO 2 |
793 | #define WMULT_IDLEPRIO (1 << 31) | |
794 | ||
795 | /* | |
796 | * Nice levels are multiplicative, with a gentle 10% change for every | |
797 | * nice level changed. I.e. when a CPU-bound task goes from nice 0 to | |
798 | * nice 1, it will get ~10% less CPU time than another CPU-bound task | |
799 | * that remained on nice 0. | |
800 | * | |
801 | * The "10% effect" is relative and cumulative: from _any_ nice level, | |
802 | * if you go up 1 level, it's -10% CPU usage, if you go down 1 level | |
f9153ee6 IM |
803 | * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25. |
804 | * If a task goes up by ~10% and another task goes down by ~10% then | |
805 | * the relative distance between them is ~25%.) | |
dd41f596 IM |
806 | */ |
807 | static const int prio_to_weight[40] = { | |
254753dc IM |
808 | /* -20 */ 88761, 71755, 56483, 46273, 36291, |
809 | /* -15 */ 29154, 23254, 18705, 14949, 11916, | |
810 | /* -10 */ 9548, 7620, 6100, 4904, 3906, | |
811 | /* -5 */ 3121, 2501, 1991, 1586, 1277, | |
812 | /* 0 */ 1024, 820, 655, 526, 423, | |
813 | /* 5 */ 335, 272, 215, 172, 137, | |
814 | /* 10 */ 110, 87, 70, 56, 45, | |
815 | /* 15 */ 36, 29, 23, 18, 15, | |
dd41f596 IM |
816 | }; |
817 | ||
5714d2de IM |
818 | /* |
819 | * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated. | |
820 | * | |
821 | * In cases where the weight does not change often, we can use the | |
822 | * precalculated inverse to speed up arithmetics by turning divisions | |
823 | * into multiplications: | |
824 | */ | |
dd41f596 | 825 | static const u32 prio_to_wmult[40] = { |
254753dc IM |
826 | /* -20 */ 48388, 59856, 76040, 92818, 118348, |
827 | /* -15 */ 147320, 184698, 229616, 287308, 360437, | |
828 | /* -10 */ 449829, 563644, 704093, 875809, 1099582, | |
829 | /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326, | |
830 | /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587, | |
831 | /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126, | |
832 | /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717, | |
833 | /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153, | |
dd41f596 | 834 | }; |
2dd73a4f | 835 | |
dd41f596 IM |
836 | static void activate_task(struct rq *rq, struct task_struct *p, int wakeup); |
837 | ||
838 | /* | |
839 | * runqueue iterator, to support SMP load-balancing between different | |
840 | * scheduling classes, without having to expose their internal data | |
841 | * structures to the load-balancing proper: | |
842 | */ | |
843 | struct rq_iterator { | |
844 | void *arg; | |
845 | struct task_struct *(*start)(void *); | |
846 | struct task_struct *(*next)(void *); | |
847 | }; | |
848 | ||
e1d1484f PW |
849 | #ifdef CONFIG_SMP |
850 | static unsigned long | |
851 | balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
852 | unsigned long max_load_move, struct sched_domain *sd, | |
853 | enum cpu_idle_type idle, int *all_pinned, | |
854 | int *this_best_prio, struct rq_iterator *iterator); | |
855 | ||
856 | static int | |
857 | iter_move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
858 | struct sched_domain *sd, enum cpu_idle_type idle, | |
859 | struct rq_iterator *iterator); | |
e1d1484f | 860 | #endif |
dd41f596 | 861 | |
d842de87 SV |
862 | #ifdef CONFIG_CGROUP_CPUACCT |
863 | static void cpuacct_charge(struct task_struct *tsk, u64 cputime); | |
864 | #else | |
865 | static inline void cpuacct_charge(struct task_struct *tsk, u64 cputime) {} | |
866 | #endif | |
867 | ||
dd41f596 | 868 | #include "sched_stats.h" |
dd41f596 | 869 | #include "sched_idletask.c" |
5522d5d5 IM |
870 | #include "sched_fair.c" |
871 | #include "sched_rt.c" | |
dd41f596 IM |
872 | #ifdef CONFIG_SCHED_DEBUG |
873 | # include "sched_debug.c" | |
874 | #endif | |
875 | ||
876 | #define sched_class_highest (&rt_sched_class) | |
877 | ||
9c217245 IM |
878 | /* |
879 | * Update delta_exec, delta_fair fields for rq. | |
880 | * | |
881 | * delta_fair clock advances at a rate inversely proportional to | |
495eca49 | 882 | * total load (rq->load.weight) on the runqueue, while |
9c217245 IM |
883 | * delta_exec advances at the same rate as wall-clock (provided |
884 | * cpu is not idle). | |
885 | * | |
886 | * delta_exec / delta_fair is a measure of the (smoothened) load on this | |
887 | * runqueue over any given interval. This (smoothened) load is used | |
888 | * during load balance. | |
889 | * | |
495eca49 | 890 | * This function is called /before/ updating rq->load |
9c217245 IM |
891 | * and when switching tasks. |
892 | */ | |
29b4b623 | 893 | static inline void inc_load(struct rq *rq, const struct task_struct *p) |
9c217245 | 894 | { |
495eca49 | 895 | update_load_add(&rq->load, p->se.load.weight); |
9c217245 IM |
896 | } |
897 | ||
79b5dddf | 898 | static inline void dec_load(struct rq *rq, const struct task_struct *p) |
9c217245 | 899 | { |
495eca49 | 900 | update_load_sub(&rq->load, p->se.load.weight); |
9c217245 IM |
901 | } |
902 | ||
e5fa2237 | 903 | static void inc_nr_running(struct task_struct *p, struct rq *rq) |
9c217245 IM |
904 | { |
905 | rq->nr_running++; | |
29b4b623 | 906 | inc_load(rq, p); |
9c217245 IM |
907 | } |
908 | ||
db53181e | 909 | static void dec_nr_running(struct task_struct *p, struct rq *rq) |
9c217245 IM |
910 | { |
911 | rq->nr_running--; | |
79b5dddf | 912 | dec_load(rq, p); |
9c217245 IM |
913 | } |
914 | ||
45bf76df IM |
915 | static void set_load_weight(struct task_struct *p) |
916 | { | |
917 | if (task_has_rt_policy(p)) { | |
dd41f596 IM |
918 | p->se.load.weight = prio_to_weight[0] * 2; |
919 | p->se.load.inv_weight = prio_to_wmult[0] >> 1; | |
920 | return; | |
921 | } | |
45bf76df | 922 | |
dd41f596 IM |
923 | /* |
924 | * SCHED_IDLE tasks get minimal weight: | |
925 | */ | |
926 | if (p->policy == SCHED_IDLE) { | |
927 | p->se.load.weight = WEIGHT_IDLEPRIO; | |
928 | p->se.load.inv_weight = WMULT_IDLEPRIO; | |
929 | return; | |
930 | } | |
71f8bd46 | 931 | |
dd41f596 IM |
932 | p->se.load.weight = prio_to_weight[p->static_prio - MAX_RT_PRIO]; |
933 | p->se.load.inv_weight = prio_to_wmult[p->static_prio - MAX_RT_PRIO]; | |
71f8bd46 IM |
934 | } |
935 | ||
8159f87e | 936 | static void enqueue_task(struct rq *rq, struct task_struct *p, int wakeup) |
71f8bd46 | 937 | { |
dd41f596 | 938 | sched_info_queued(p); |
fd390f6a | 939 | p->sched_class->enqueue_task(rq, p, wakeup); |
dd41f596 | 940 | p->se.on_rq = 1; |
71f8bd46 IM |
941 | } |
942 | ||
69be72c1 | 943 | static void dequeue_task(struct rq *rq, struct task_struct *p, int sleep) |
71f8bd46 | 944 | { |
f02231e5 | 945 | p->sched_class->dequeue_task(rq, p, sleep); |
dd41f596 | 946 | p->se.on_rq = 0; |
71f8bd46 IM |
947 | } |
948 | ||
14531189 | 949 | /* |
dd41f596 | 950 | * __normal_prio - return the priority that is based on the static prio |
14531189 | 951 | */ |
14531189 IM |
952 | static inline int __normal_prio(struct task_struct *p) |
953 | { | |
dd41f596 | 954 | return p->static_prio; |
14531189 IM |
955 | } |
956 | ||
b29739f9 IM |
957 | /* |
958 | * Calculate the expected normal priority: i.e. priority | |
959 | * without taking RT-inheritance into account. Might be | |
960 | * boosted by interactivity modifiers. Changes upon fork, | |
961 | * setprio syscalls, and whenever the interactivity | |
962 | * estimator recalculates. | |
963 | */ | |
36c8b586 | 964 | static inline int normal_prio(struct task_struct *p) |
b29739f9 IM |
965 | { |
966 | int prio; | |
967 | ||
e05606d3 | 968 | if (task_has_rt_policy(p)) |
b29739f9 IM |
969 | prio = MAX_RT_PRIO-1 - p->rt_priority; |
970 | else | |
971 | prio = __normal_prio(p); | |
972 | return prio; | |
973 | } | |
974 | ||
975 | /* | |
976 | * Calculate the current priority, i.e. the priority | |
977 | * taken into account by the scheduler. This value might | |
978 | * be boosted by RT tasks, or might be boosted by | |
979 | * interactivity modifiers. Will be RT if the task got | |
980 | * RT-boosted. If not then it returns p->normal_prio. | |
981 | */ | |
36c8b586 | 982 | static int effective_prio(struct task_struct *p) |
b29739f9 IM |
983 | { |
984 | p->normal_prio = normal_prio(p); | |
985 | /* | |
986 | * If we are RT tasks or we were boosted to RT priority, | |
987 | * keep the priority unchanged. Otherwise, update priority | |
988 | * to the normal priority: | |
989 | */ | |
990 | if (!rt_prio(p->prio)) | |
991 | return p->normal_prio; | |
992 | return p->prio; | |
993 | } | |
994 | ||
1da177e4 | 995 | /* |
dd41f596 | 996 | * activate_task - move a task to the runqueue. |
1da177e4 | 997 | */ |
dd41f596 | 998 | static void activate_task(struct rq *rq, struct task_struct *p, int wakeup) |
1da177e4 | 999 | { |
dd41f596 IM |
1000 | if (p->state == TASK_UNINTERRUPTIBLE) |
1001 | rq->nr_uninterruptible--; | |
1da177e4 | 1002 | |
8159f87e | 1003 | enqueue_task(rq, p, wakeup); |
e5fa2237 | 1004 | inc_nr_running(p, rq); |
1da177e4 LT |
1005 | } |
1006 | ||
1da177e4 LT |
1007 | /* |
1008 | * deactivate_task - remove a task from the runqueue. | |
1009 | */ | |
2e1cb74a | 1010 | static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep) |
1da177e4 | 1011 | { |
dd41f596 IM |
1012 | if (p->state == TASK_UNINTERRUPTIBLE) |
1013 | rq->nr_uninterruptible++; | |
1014 | ||
69be72c1 | 1015 | dequeue_task(rq, p, sleep); |
db53181e | 1016 | dec_nr_running(p, rq); |
1da177e4 LT |
1017 | } |
1018 | ||
1da177e4 LT |
1019 | /** |
1020 | * task_curr - is this task currently executing on a CPU? | |
1021 | * @p: the task in question. | |
1022 | */ | |
36c8b586 | 1023 | inline int task_curr(const struct task_struct *p) |
1da177e4 LT |
1024 | { |
1025 | return cpu_curr(task_cpu(p)) == p; | |
1026 | } | |
1027 | ||
2dd73a4f PW |
1028 | /* Used instead of source_load when we know the type == 0 */ |
1029 | unsigned long weighted_cpuload(const int cpu) | |
1030 | { | |
495eca49 | 1031 | return cpu_rq(cpu)->load.weight; |
dd41f596 IM |
1032 | } |
1033 | ||
1034 | static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu) | |
1035 | { | |
ce96b5ac | 1036 | set_task_cfs_rq(p, cpu); |
dd41f596 | 1037 | #ifdef CONFIG_SMP |
ce96b5ac DA |
1038 | /* |
1039 | * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be | |
1040 | * successfuly executed on another CPU. We must ensure that updates of | |
1041 | * per-task data have been completed by this moment. | |
1042 | */ | |
1043 | smp_wmb(); | |
dd41f596 | 1044 | task_thread_info(p)->cpu = cpu; |
dd41f596 | 1045 | #endif |
2dd73a4f PW |
1046 | } |
1047 | ||
1da177e4 | 1048 | #ifdef CONFIG_SMP |
c65cc870 | 1049 | |
cc367732 IM |
1050 | /* |
1051 | * Is this task likely cache-hot: | |
1052 | */ | |
1053 | static inline int | |
1054 | task_hot(struct task_struct *p, u64 now, struct sched_domain *sd) | |
1055 | { | |
1056 | s64 delta; | |
1057 | ||
1058 | if (p->sched_class != &fair_sched_class) | |
1059 | return 0; | |
1060 | ||
6bc1665b IM |
1061 | if (sysctl_sched_migration_cost == -1) |
1062 | return 1; | |
1063 | if (sysctl_sched_migration_cost == 0) | |
1064 | return 0; | |
1065 | ||
cc367732 IM |
1066 | delta = now - p->se.exec_start; |
1067 | ||
1068 | return delta < (s64)sysctl_sched_migration_cost; | |
1069 | } | |
1070 | ||
1071 | ||
dd41f596 | 1072 | void set_task_cpu(struct task_struct *p, unsigned int new_cpu) |
c65cc870 | 1073 | { |
dd41f596 IM |
1074 | int old_cpu = task_cpu(p); |
1075 | struct rq *old_rq = cpu_rq(old_cpu), *new_rq = cpu_rq(new_cpu); | |
2830cf8c SV |
1076 | struct cfs_rq *old_cfsrq = task_cfs_rq(p), |
1077 | *new_cfsrq = cpu_cfs_rq(old_cfsrq, new_cpu); | |
bbdba7c0 | 1078 | u64 clock_offset; |
dd41f596 IM |
1079 | |
1080 | clock_offset = old_rq->clock - new_rq->clock; | |
6cfb0d5d IM |
1081 | |
1082 | #ifdef CONFIG_SCHEDSTATS | |
1083 | if (p->se.wait_start) | |
1084 | p->se.wait_start -= clock_offset; | |
dd41f596 IM |
1085 | if (p->se.sleep_start) |
1086 | p->se.sleep_start -= clock_offset; | |
1087 | if (p->se.block_start) | |
1088 | p->se.block_start -= clock_offset; | |
cc367732 IM |
1089 | if (old_cpu != new_cpu) { |
1090 | schedstat_inc(p, se.nr_migrations); | |
1091 | if (task_hot(p, old_rq->clock, NULL)) | |
1092 | schedstat_inc(p, se.nr_forced2_migrations); | |
1093 | } | |
6cfb0d5d | 1094 | #endif |
2830cf8c SV |
1095 | p->se.vruntime -= old_cfsrq->min_vruntime - |
1096 | new_cfsrq->min_vruntime; | |
dd41f596 IM |
1097 | |
1098 | __set_task_cpu(p, new_cpu); | |
c65cc870 IM |
1099 | } |
1100 | ||
70b97a7f | 1101 | struct migration_req { |
1da177e4 | 1102 | struct list_head list; |
1da177e4 | 1103 | |
36c8b586 | 1104 | struct task_struct *task; |
1da177e4 LT |
1105 | int dest_cpu; |
1106 | ||
1da177e4 | 1107 | struct completion done; |
70b97a7f | 1108 | }; |
1da177e4 LT |
1109 | |
1110 | /* | |
1111 | * The task's runqueue lock must be held. | |
1112 | * Returns true if you have to wait for migration thread. | |
1113 | */ | |
36c8b586 | 1114 | static int |
70b97a7f | 1115 | migrate_task(struct task_struct *p, int dest_cpu, struct migration_req *req) |
1da177e4 | 1116 | { |
70b97a7f | 1117 | struct rq *rq = task_rq(p); |
1da177e4 LT |
1118 | |
1119 | /* | |
1120 | * If the task is not on a runqueue (and not running), then | |
1121 | * it is sufficient to simply update the task's cpu field. | |
1122 | */ | |
dd41f596 | 1123 | if (!p->se.on_rq && !task_running(rq, p)) { |
1da177e4 LT |
1124 | set_task_cpu(p, dest_cpu); |
1125 | return 0; | |
1126 | } | |
1127 | ||
1128 | init_completion(&req->done); | |
1da177e4 LT |
1129 | req->task = p; |
1130 | req->dest_cpu = dest_cpu; | |
1131 | list_add(&req->list, &rq->migration_queue); | |
48f24c4d | 1132 | |
1da177e4 LT |
1133 | return 1; |
1134 | } | |
1135 | ||
1136 | /* | |
1137 | * wait_task_inactive - wait for a thread to unschedule. | |
1138 | * | |
1139 | * The caller must ensure that the task *will* unschedule sometime soon, | |
1140 | * else this function might spin for a *long* time. This function can't | |
1141 | * be called with interrupts off, or it may introduce deadlock with | |
1142 | * smp_call_function() if an IPI is sent by the same process we are | |
1143 | * waiting to become inactive. | |
1144 | */ | |
36c8b586 | 1145 | void wait_task_inactive(struct task_struct *p) |
1da177e4 LT |
1146 | { |
1147 | unsigned long flags; | |
dd41f596 | 1148 | int running, on_rq; |
70b97a7f | 1149 | struct rq *rq; |
1da177e4 | 1150 | |
3a5c359a AK |
1151 | for (;;) { |
1152 | /* | |
1153 | * We do the initial early heuristics without holding | |
1154 | * any task-queue locks at all. We'll only try to get | |
1155 | * the runqueue lock when things look like they will | |
1156 | * work out! | |
1157 | */ | |
1158 | rq = task_rq(p); | |
fa490cfd | 1159 | |
3a5c359a AK |
1160 | /* |
1161 | * If the task is actively running on another CPU | |
1162 | * still, just relax and busy-wait without holding | |
1163 | * any locks. | |
1164 | * | |
1165 | * NOTE! Since we don't hold any locks, it's not | |
1166 | * even sure that "rq" stays as the right runqueue! | |
1167 | * But we don't care, since "task_running()" will | |
1168 | * return false if the runqueue has changed and p | |
1169 | * is actually now running somewhere else! | |
1170 | */ | |
1171 | while (task_running(rq, p)) | |
1172 | cpu_relax(); | |
fa490cfd | 1173 | |
3a5c359a AK |
1174 | /* |
1175 | * Ok, time to look more closely! We need the rq | |
1176 | * lock now, to be *sure*. If we're wrong, we'll | |
1177 | * just go back and repeat. | |
1178 | */ | |
1179 | rq = task_rq_lock(p, &flags); | |
1180 | running = task_running(rq, p); | |
1181 | on_rq = p->se.on_rq; | |
1182 | task_rq_unlock(rq, &flags); | |
fa490cfd | 1183 | |
3a5c359a AK |
1184 | /* |
1185 | * Was it really running after all now that we | |
1186 | * checked with the proper locks actually held? | |
1187 | * | |
1188 | * Oops. Go back and try again.. | |
1189 | */ | |
1190 | if (unlikely(running)) { | |
1191 | cpu_relax(); | |
1192 | continue; | |
1193 | } | |
fa490cfd | 1194 | |
3a5c359a AK |
1195 | /* |
1196 | * It's not enough that it's not actively running, | |
1197 | * it must be off the runqueue _entirely_, and not | |
1198 | * preempted! | |
1199 | * | |
1200 | * So if it wa still runnable (but just not actively | |
1201 | * running right now), it's preempted, and we should | |
1202 | * yield - it could be a while. | |
1203 | */ | |
1204 | if (unlikely(on_rq)) { | |
1205 | schedule_timeout_uninterruptible(1); | |
1206 | continue; | |
1207 | } | |
fa490cfd | 1208 | |
3a5c359a AK |
1209 | /* |
1210 | * Ahh, all good. It wasn't running, and it wasn't | |
1211 | * runnable, which means that it will never become | |
1212 | * running in the future either. We're all done! | |
1213 | */ | |
1214 | break; | |
1215 | } | |
1da177e4 LT |
1216 | } |
1217 | ||
1218 | /*** | |
1219 | * kick_process - kick a running thread to enter/exit the kernel | |
1220 | * @p: the to-be-kicked thread | |
1221 | * | |
1222 | * Cause a process which is running on another CPU to enter | |
1223 | * kernel-mode, without any delay. (to get signals handled.) | |
1224 | * | |
1225 | * NOTE: this function doesnt have to take the runqueue lock, | |
1226 | * because all it wants to ensure is that the remote task enters | |
1227 | * the kernel. If the IPI races and the task has been migrated | |
1228 | * to another CPU then no harm is done and the purpose has been | |
1229 | * achieved as well. | |
1230 | */ | |
36c8b586 | 1231 | void kick_process(struct task_struct *p) |
1da177e4 LT |
1232 | { |
1233 | int cpu; | |
1234 | ||
1235 | preempt_disable(); | |
1236 | cpu = task_cpu(p); | |
1237 | if ((cpu != smp_processor_id()) && task_curr(p)) | |
1238 | smp_send_reschedule(cpu); | |
1239 | preempt_enable(); | |
1240 | } | |
1241 | ||
1242 | /* | |
2dd73a4f PW |
1243 | * Return a low guess at the load of a migration-source cpu weighted |
1244 | * according to the scheduling class and "nice" value. | |
1da177e4 LT |
1245 | * |
1246 | * We want to under-estimate the load of migration sources, to | |
1247 | * balance conservatively. | |
1248 | */ | |
a9957449 | 1249 | static unsigned long source_load(int cpu, int type) |
1da177e4 | 1250 | { |
70b97a7f | 1251 | struct rq *rq = cpu_rq(cpu); |
dd41f596 | 1252 | unsigned long total = weighted_cpuload(cpu); |
2dd73a4f | 1253 | |
3b0bd9bc | 1254 | if (type == 0) |
dd41f596 | 1255 | return total; |
b910472d | 1256 | |
dd41f596 | 1257 | return min(rq->cpu_load[type-1], total); |
1da177e4 LT |
1258 | } |
1259 | ||
1260 | /* | |
2dd73a4f PW |
1261 | * Return a high guess at the load of a migration-target cpu weighted |
1262 | * according to the scheduling class and "nice" value. | |
1da177e4 | 1263 | */ |
a9957449 | 1264 | static unsigned long target_load(int cpu, int type) |
1da177e4 | 1265 | { |
70b97a7f | 1266 | struct rq *rq = cpu_rq(cpu); |
dd41f596 | 1267 | unsigned long total = weighted_cpuload(cpu); |
2dd73a4f | 1268 | |
7897986b | 1269 | if (type == 0) |
dd41f596 | 1270 | return total; |
3b0bd9bc | 1271 | |
dd41f596 | 1272 | return max(rq->cpu_load[type-1], total); |
2dd73a4f PW |
1273 | } |
1274 | ||
1275 | /* | |
1276 | * Return the average load per task on the cpu's run queue | |
1277 | */ | |
1278 | static inline unsigned long cpu_avg_load_per_task(int cpu) | |
1279 | { | |
70b97a7f | 1280 | struct rq *rq = cpu_rq(cpu); |
dd41f596 | 1281 | unsigned long total = weighted_cpuload(cpu); |
2dd73a4f PW |
1282 | unsigned long n = rq->nr_running; |
1283 | ||
dd41f596 | 1284 | return n ? total / n : SCHED_LOAD_SCALE; |
1da177e4 LT |
1285 | } |
1286 | ||
147cbb4b NP |
1287 | /* |
1288 | * find_idlest_group finds and returns the least busy CPU group within the | |
1289 | * domain. | |
1290 | */ | |
1291 | static struct sched_group * | |
1292 | find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu) | |
1293 | { | |
1294 | struct sched_group *idlest = NULL, *this = NULL, *group = sd->groups; | |
1295 | unsigned long min_load = ULONG_MAX, this_load = 0; | |
1296 | int load_idx = sd->forkexec_idx; | |
1297 | int imbalance = 100 + (sd->imbalance_pct-100)/2; | |
1298 | ||
1299 | do { | |
1300 | unsigned long load, avg_load; | |
1301 | int local_group; | |
1302 | int i; | |
1303 | ||
da5a5522 BD |
1304 | /* Skip over this group if it has no CPUs allowed */ |
1305 | if (!cpus_intersects(group->cpumask, p->cpus_allowed)) | |
3a5c359a | 1306 | continue; |
da5a5522 | 1307 | |
147cbb4b | 1308 | local_group = cpu_isset(this_cpu, group->cpumask); |
147cbb4b NP |
1309 | |
1310 | /* Tally up the load of all CPUs in the group */ | |
1311 | avg_load = 0; | |
1312 | ||
1313 | for_each_cpu_mask(i, group->cpumask) { | |
1314 | /* Bias balancing toward cpus of our domain */ | |
1315 | if (local_group) | |
1316 | load = source_load(i, load_idx); | |
1317 | else | |
1318 | load = target_load(i, load_idx); | |
1319 | ||
1320 | avg_load += load; | |
1321 | } | |
1322 | ||
1323 | /* Adjust by relative CPU power of the group */ | |
5517d86b ED |
1324 | avg_load = sg_div_cpu_power(group, |
1325 | avg_load * SCHED_LOAD_SCALE); | |
147cbb4b NP |
1326 | |
1327 | if (local_group) { | |
1328 | this_load = avg_load; | |
1329 | this = group; | |
1330 | } else if (avg_load < min_load) { | |
1331 | min_load = avg_load; | |
1332 | idlest = group; | |
1333 | } | |
3a5c359a | 1334 | } while (group = group->next, group != sd->groups); |
147cbb4b NP |
1335 | |
1336 | if (!idlest || 100*this_load < imbalance*min_load) | |
1337 | return NULL; | |
1338 | return idlest; | |
1339 | } | |
1340 | ||
1341 | /* | |
0feaece9 | 1342 | * find_idlest_cpu - find the idlest cpu among the cpus in group. |
147cbb4b | 1343 | */ |
95cdf3b7 IM |
1344 | static int |
1345 | find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu) | |
147cbb4b | 1346 | { |
da5a5522 | 1347 | cpumask_t tmp; |
147cbb4b NP |
1348 | unsigned long load, min_load = ULONG_MAX; |
1349 | int idlest = -1; | |
1350 | int i; | |
1351 | ||
da5a5522 BD |
1352 | /* Traverse only the allowed CPUs */ |
1353 | cpus_and(tmp, group->cpumask, p->cpus_allowed); | |
1354 | ||
1355 | for_each_cpu_mask(i, tmp) { | |
2dd73a4f | 1356 | load = weighted_cpuload(i); |
147cbb4b NP |
1357 | |
1358 | if (load < min_load || (load == min_load && i == this_cpu)) { | |
1359 | min_load = load; | |
1360 | idlest = i; | |
1361 | } | |
1362 | } | |
1363 | ||
1364 | return idlest; | |
1365 | } | |
1366 | ||
476d139c NP |
1367 | /* |
1368 | * sched_balance_self: balance the current task (running on cpu) in domains | |
1369 | * that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and | |
1370 | * SD_BALANCE_EXEC. | |
1371 | * | |
1372 | * Balance, ie. select the least loaded group. | |
1373 | * | |
1374 | * Returns the target CPU number, or the same CPU if no balancing is needed. | |
1375 | * | |
1376 | * preempt must be disabled. | |
1377 | */ | |
1378 | static int sched_balance_self(int cpu, int flag) | |
1379 | { | |
1380 | struct task_struct *t = current; | |
1381 | struct sched_domain *tmp, *sd = NULL; | |
147cbb4b | 1382 | |
c96d145e | 1383 | for_each_domain(cpu, tmp) { |
9761eea8 IM |
1384 | /* |
1385 | * If power savings logic is enabled for a domain, stop there. | |
1386 | */ | |
5c45bf27 SS |
1387 | if (tmp->flags & SD_POWERSAVINGS_BALANCE) |
1388 | break; | |
476d139c NP |
1389 | if (tmp->flags & flag) |
1390 | sd = tmp; | |
c96d145e | 1391 | } |
476d139c NP |
1392 | |
1393 | while (sd) { | |
1394 | cpumask_t span; | |
1395 | struct sched_group *group; | |
1a848870 SS |
1396 | int new_cpu, weight; |
1397 | ||
1398 | if (!(sd->flags & flag)) { | |
1399 | sd = sd->child; | |
1400 | continue; | |
1401 | } | |
476d139c NP |
1402 | |
1403 | span = sd->span; | |
1404 | group = find_idlest_group(sd, t, cpu); | |
1a848870 SS |
1405 | if (!group) { |
1406 | sd = sd->child; | |
1407 | continue; | |
1408 | } | |
476d139c | 1409 | |
da5a5522 | 1410 | new_cpu = find_idlest_cpu(group, t, cpu); |
1a848870 SS |
1411 | if (new_cpu == -1 || new_cpu == cpu) { |
1412 | /* Now try balancing at a lower domain level of cpu */ | |
1413 | sd = sd->child; | |
1414 | continue; | |
1415 | } | |
476d139c | 1416 | |
1a848870 | 1417 | /* Now try balancing at a lower domain level of new_cpu */ |
476d139c | 1418 | cpu = new_cpu; |
476d139c NP |
1419 | sd = NULL; |
1420 | weight = cpus_weight(span); | |
1421 | for_each_domain(cpu, tmp) { | |
1422 | if (weight <= cpus_weight(tmp->span)) | |
1423 | break; | |
1424 | if (tmp->flags & flag) | |
1425 | sd = tmp; | |
1426 | } | |
1427 | /* while loop will break here if sd == NULL */ | |
1428 | } | |
1429 | ||
1430 | return cpu; | |
1431 | } | |
1432 | ||
1433 | #endif /* CONFIG_SMP */ | |
1da177e4 LT |
1434 | |
1435 | /* | |
1436 | * wake_idle() will wake a task on an idle cpu if task->cpu is | |
1437 | * not idle and an idle cpu is available. The span of cpus to | |
1438 | * search starts with cpus closest then further out as needed, | |
1439 | * so we always favor a closer, idle cpu. | |
1440 | * | |
1441 | * Returns the CPU we should wake onto. | |
1442 | */ | |
1443 | #if defined(ARCH_HAS_SCHED_WAKE_IDLE) | |
36c8b586 | 1444 | static int wake_idle(int cpu, struct task_struct *p) |
1da177e4 LT |
1445 | { |
1446 | cpumask_t tmp; | |
1447 | struct sched_domain *sd; | |
1448 | int i; | |
1449 | ||
4953198b SS |
1450 | /* |
1451 | * If it is idle, then it is the best cpu to run this task. | |
1452 | * | |
1453 | * This cpu is also the best, if it has more than one task already. | |
1454 | * Siblings must be also busy(in most cases) as they didn't already | |
1455 | * pickup the extra load from this cpu and hence we need not check | |
1456 | * sibling runqueue info. This will avoid the checks and cache miss | |
1457 | * penalities associated with that. | |
1458 | */ | |
1459 | if (idle_cpu(cpu) || cpu_rq(cpu)->nr_running > 1) | |
1da177e4 LT |
1460 | return cpu; |
1461 | ||
1462 | for_each_domain(cpu, sd) { | |
1463 | if (sd->flags & SD_WAKE_IDLE) { | |
e0f364f4 | 1464 | cpus_and(tmp, sd->span, p->cpus_allowed); |
1da177e4 | 1465 | for_each_cpu_mask(i, tmp) { |
cc367732 IM |
1466 | if (idle_cpu(i)) { |
1467 | if (i != task_cpu(p)) { | |
1468 | schedstat_inc(p, | |
1469 | se.nr_wakeups_idle); | |
1470 | } | |
1da177e4 | 1471 | return i; |
cc367732 | 1472 | } |
1da177e4 | 1473 | } |
9761eea8 | 1474 | } else { |
e0f364f4 | 1475 | break; |
9761eea8 | 1476 | } |
1da177e4 LT |
1477 | } |
1478 | return cpu; | |
1479 | } | |
1480 | #else | |
36c8b586 | 1481 | static inline int wake_idle(int cpu, struct task_struct *p) |
1da177e4 LT |
1482 | { |
1483 | return cpu; | |
1484 | } | |
1485 | #endif | |
1486 | ||
1487 | /*** | |
1488 | * try_to_wake_up - wake up a thread | |
1489 | * @p: the to-be-woken-up thread | |
1490 | * @state: the mask of task states that can be woken | |
1491 | * @sync: do a synchronous wakeup? | |
1492 | * | |
1493 | * Put it on the run-queue if it's not already there. The "current" | |
1494 | * thread is always on the run-queue (except when the actual | |
1495 | * re-schedule is in progress), and as such you're allowed to do | |
1496 | * the simpler "current->state = TASK_RUNNING" to mark yourself | |
1497 | * runnable without the overhead of this. | |
1498 | * | |
1499 | * returns failure only if the task is already active. | |
1500 | */ | |
36c8b586 | 1501 | static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync) |
1da177e4 | 1502 | { |
cc367732 | 1503 | int cpu, orig_cpu, this_cpu, success = 0; |
1da177e4 LT |
1504 | unsigned long flags; |
1505 | long old_state; | |
70b97a7f | 1506 | struct rq *rq; |
1da177e4 | 1507 | #ifdef CONFIG_SMP |
7897986b | 1508 | struct sched_domain *sd, *this_sd = NULL; |
70b97a7f | 1509 | unsigned long load, this_load; |
1da177e4 LT |
1510 | int new_cpu; |
1511 | #endif | |
1512 | ||
1513 | rq = task_rq_lock(p, &flags); | |
1514 | old_state = p->state; | |
1515 | if (!(old_state & state)) | |
1516 | goto out; | |
1517 | ||
dd41f596 | 1518 | if (p->se.on_rq) |
1da177e4 LT |
1519 | goto out_running; |
1520 | ||
1521 | cpu = task_cpu(p); | |
cc367732 | 1522 | orig_cpu = cpu; |
1da177e4 LT |
1523 | this_cpu = smp_processor_id(); |
1524 | ||
1525 | #ifdef CONFIG_SMP | |
1526 | if (unlikely(task_running(rq, p))) | |
1527 | goto out_activate; | |
1528 | ||
7897986b NP |
1529 | new_cpu = cpu; |
1530 | ||
2d72376b | 1531 | schedstat_inc(rq, ttwu_count); |
1da177e4 LT |
1532 | if (cpu == this_cpu) { |
1533 | schedstat_inc(rq, ttwu_local); | |
7897986b NP |
1534 | goto out_set_cpu; |
1535 | } | |
1536 | ||
1537 | for_each_domain(this_cpu, sd) { | |
1538 | if (cpu_isset(cpu, sd->span)) { | |
1539 | schedstat_inc(sd, ttwu_wake_remote); | |
1540 | this_sd = sd; | |
1541 | break; | |
1da177e4 LT |
1542 | } |
1543 | } | |
1da177e4 | 1544 | |
7897986b | 1545 | if (unlikely(!cpu_isset(this_cpu, p->cpus_allowed))) |
1da177e4 LT |
1546 | goto out_set_cpu; |
1547 | ||
1da177e4 | 1548 | /* |
7897986b | 1549 | * Check for affine wakeup and passive balancing possibilities. |
1da177e4 | 1550 | */ |
7897986b NP |
1551 | if (this_sd) { |
1552 | int idx = this_sd->wake_idx; | |
1553 | unsigned int imbalance; | |
1da177e4 | 1554 | |
a3f21bce NP |
1555 | imbalance = 100 + (this_sd->imbalance_pct - 100) / 2; |
1556 | ||
7897986b NP |
1557 | load = source_load(cpu, idx); |
1558 | this_load = target_load(this_cpu, idx); | |
1da177e4 | 1559 | |
7897986b NP |
1560 | new_cpu = this_cpu; /* Wake to this CPU if we can */ |
1561 | ||
a3f21bce NP |
1562 | if (this_sd->flags & SD_WAKE_AFFINE) { |
1563 | unsigned long tl = this_load; | |
33859f7f MOS |
1564 | unsigned long tl_per_task; |
1565 | ||
71e20f18 IM |
1566 | /* |
1567 | * Attract cache-cold tasks on sync wakeups: | |
1568 | */ | |
1569 | if (sync && !task_hot(p, rq->clock, this_sd)) | |
1570 | goto out_set_cpu; | |
1571 | ||
cc367732 | 1572 | schedstat_inc(p, se.nr_wakeups_affine_attempts); |
33859f7f | 1573 | tl_per_task = cpu_avg_load_per_task(this_cpu); |
2dd73a4f | 1574 | |
1da177e4 | 1575 | /* |
a3f21bce NP |
1576 | * If sync wakeup then subtract the (maximum possible) |
1577 | * effect of the currently running task from the load | |
1578 | * of the current CPU: | |
1da177e4 | 1579 | */ |
a3f21bce | 1580 | if (sync) |
dd41f596 | 1581 | tl -= current->se.load.weight; |
a3f21bce NP |
1582 | |
1583 | if ((tl <= load && | |
2dd73a4f | 1584 | tl + target_load(cpu, idx) <= tl_per_task) || |
dd41f596 | 1585 | 100*(tl + p->se.load.weight) <= imbalance*load) { |
a3f21bce NP |
1586 | /* |
1587 | * This domain has SD_WAKE_AFFINE and | |
1588 | * p is cache cold in this domain, and | |
1589 | * there is no bad imbalance. | |
1590 | */ | |
1591 | schedstat_inc(this_sd, ttwu_move_affine); | |
cc367732 | 1592 | schedstat_inc(p, se.nr_wakeups_affine); |
a3f21bce NP |
1593 | goto out_set_cpu; |
1594 | } | |
1595 | } | |
1596 | ||
1597 | /* | |
1598 | * Start passive balancing when half the imbalance_pct | |
1599 | * limit is reached. | |
1600 | */ | |
1601 | if (this_sd->flags & SD_WAKE_BALANCE) { | |
1602 | if (imbalance*this_load <= 100*load) { | |
1603 | schedstat_inc(this_sd, ttwu_move_balance); | |
cc367732 | 1604 | schedstat_inc(p, se.nr_wakeups_passive); |
a3f21bce NP |
1605 | goto out_set_cpu; |
1606 | } | |
1da177e4 LT |
1607 | } |
1608 | } | |
1609 | ||
1610 | new_cpu = cpu; /* Could not wake to this_cpu. Wake to cpu instead */ | |
1611 | out_set_cpu: | |
1612 | new_cpu = wake_idle(new_cpu, p); | |
1613 | if (new_cpu != cpu) { | |
1614 | set_task_cpu(p, new_cpu); | |
1615 | task_rq_unlock(rq, &flags); | |
1616 | /* might preempt at this point */ | |
1617 | rq = task_rq_lock(p, &flags); | |
1618 | old_state = p->state; | |
1619 | if (!(old_state & state)) | |
1620 | goto out; | |
dd41f596 | 1621 | if (p->se.on_rq) |
1da177e4 LT |
1622 | goto out_running; |
1623 | ||
1624 | this_cpu = smp_processor_id(); | |
1625 | cpu = task_cpu(p); | |
1626 | } | |
1627 | ||
1628 | out_activate: | |
1629 | #endif /* CONFIG_SMP */ | |
cc367732 IM |
1630 | schedstat_inc(p, se.nr_wakeups); |
1631 | if (sync) | |
1632 | schedstat_inc(p, se.nr_wakeups_sync); | |
1633 | if (orig_cpu != cpu) | |
1634 | schedstat_inc(p, se.nr_wakeups_migrate); | |
1635 | if (cpu == this_cpu) | |
1636 | schedstat_inc(p, se.nr_wakeups_local); | |
1637 | else | |
1638 | schedstat_inc(p, se.nr_wakeups_remote); | |
2daa3577 | 1639 | update_rq_clock(rq); |
dd41f596 | 1640 | activate_task(rq, p, 1); |
9c63d9c0 | 1641 | check_preempt_curr(rq, p); |
1da177e4 LT |
1642 | success = 1; |
1643 | ||
1644 | out_running: | |
1645 | p->state = TASK_RUNNING; | |
1646 | out: | |
1647 | task_rq_unlock(rq, &flags); | |
1648 | ||
1649 | return success; | |
1650 | } | |
1651 | ||
36c8b586 | 1652 | int fastcall wake_up_process(struct task_struct *p) |
1da177e4 LT |
1653 | { |
1654 | return try_to_wake_up(p, TASK_STOPPED | TASK_TRACED | | |
1655 | TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE, 0); | |
1656 | } | |
1da177e4 LT |
1657 | EXPORT_SYMBOL(wake_up_process); |
1658 | ||
36c8b586 | 1659 | int fastcall wake_up_state(struct task_struct *p, unsigned int state) |
1da177e4 LT |
1660 | { |
1661 | return try_to_wake_up(p, state, 0); | |
1662 | } | |
1663 | ||
1da177e4 LT |
1664 | /* |
1665 | * Perform scheduler related setup for a newly forked process p. | |
1666 | * p is forked by current. | |
dd41f596 IM |
1667 | * |
1668 | * __sched_fork() is basic setup used by init_idle() too: | |
1669 | */ | |
1670 | static void __sched_fork(struct task_struct *p) | |
1671 | { | |
dd41f596 IM |
1672 | p->se.exec_start = 0; |
1673 | p->se.sum_exec_runtime = 0; | |
f6cf891c | 1674 | p->se.prev_sum_exec_runtime = 0; |
6cfb0d5d IM |
1675 | |
1676 | #ifdef CONFIG_SCHEDSTATS | |
1677 | p->se.wait_start = 0; | |
dd41f596 IM |
1678 | p->se.sum_sleep_runtime = 0; |
1679 | p->se.sleep_start = 0; | |
dd41f596 IM |
1680 | p->se.block_start = 0; |
1681 | p->se.sleep_max = 0; | |
1682 | p->se.block_max = 0; | |
1683 | p->se.exec_max = 0; | |
eba1ed4b | 1684 | p->se.slice_max = 0; |
dd41f596 | 1685 | p->se.wait_max = 0; |
6cfb0d5d | 1686 | #endif |
476d139c | 1687 | |
dd41f596 IM |
1688 | INIT_LIST_HEAD(&p->run_list); |
1689 | p->se.on_rq = 0; | |
476d139c | 1690 | |
e107be36 AK |
1691 | #ifdef CONFIG_PREEMPT_NOTIFIERS |
1692 | INIT_HLIST_HEAD(&p->preempt_notifiers); | |
1693 | #endif | |
1694 | ||
1da177e4 LT |
1695 | /* |
1696 | * We mark the process as running here, but have not actually | |
1697 | * inserted it onto the runqueue yet. This guarantees that | |
1698 | * nobody will actually run it, and a signal or other external | |
1699 | * event cannot wake it up and insert it on the runqueue either. | |
1700 | */ | |
1701 | p->state = TASK_RUNNING; | |
dd41f596 IM |
1702 | } |
1703 | ||
1704 | /* | |
1705 | * fork()/clone()-time setup: | |
1706 | */ | |
1707 | void sched_fork(struct task_struct *p, int clone_flags) | |
1708 | { | |
1709 | int cpu = get_cpu(); | |
1710 | ||
1711 | __sched_fork(p); | |
1712 | ||
1713 | #ifdef CONFIG_SMP | |
1714 | cpu = sched_balance_self(cpu, SD_BALANCE_FORK); | |
1715 | #endif | |
02e4bac2 | 1716 | set_task_cpu(p, cpu); |
b29739f9 IM |
1717 | |
1718 | /* | |
1719 | * Make sure we do not leak PI boosting priority to the child: | |
1720 | */ | |
1721 | p->prio = current->normal_prio; | |
2ddbf952 HS |
1722 | if (!rt_prio(p->prio)) |
1723 | p->sched_class = &fair_sched_class; | |
b29739f9 | 1724 | |
52f17b6c | 1725 | #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) |
dd41f596 | 1726 | if (likely(sched_info_on())) |
52f17b6c | 1727 | memset(&p->sched_info, 0, sizeof(p->sched_info)); |
1da177e4 | 1728 | #endif |
d6077cb8 | 1729 | #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW) |
4866cde0 NP |
1730 | p->oncpu = 0; |
1731 | #endif | |
1da177e4 | 1732 | #ifdef CONFIG_PREEMPT |
4866cde0 | 1733 | /* Want to start with kernel preemption disabled. */ |
a1261f54 | 1734 | task_thread_info(p)->preempt_count = 1; |
1da177e4 | 1735 | #endif |
476d139c | 1736 | put_cpu(); |
1da177e4 LT |
1737 | } |
1738 | ||
1739 | /* | |
1740 | * wake_up_new_task - wake up a newly created task for the first time. | |
1741 | * | |
1742 | * This function will do some initial scheduler statistics housekeeping | |
1743 | * that must be done for every newly created context, then puts the task | |
1744 | * on the runqueue and wakes it. | |
1745 | */ | |
36c8b586 | 1746 | void fastcall wake_up_new_task(struct task_struct *p, unsigned long clone_flags) |
1da177e4 LT |
1747 | { |
1748 | unsigned long flags; | |
dd41f596 | 1749 | struct rq *rq; |
1da177e4 LT |
1750 | |
1751 | rq = task_rq_lock(p, &flags); | |
147cbb4b | 1752 | BUG_ON(p->state != TASK_RUNNING); |
a8e504d2 | 1753 | update_rq_clock(rq); |
1da177e4 LT |
1754 | |
1755 | p->prio = effective_prio(p); | |
1756 | ||
b9dca1e0 | 1757 | if (!p->sched_class->task_new || !current->se.on_rq) { |
dd41f596 | 1758 | activate_task(rq, p, 0); |
1da177e4 | 1759 | } else { |
1da177e4 | 1760 | /* |
dd41f596 IM |
1761 | * Let the scheduling class do new task startup |
1762 | * management (if any): | |
1da177e4 | 1763 | */ |
ee0827d8 | 1764 | p->sched_class->task_new(rq, p); |
e5fa2237 | 1765 | inc_nr_running(p, rq); |
1da177e4 | 1766 | } |
dd41f596 IM |
1767 | check_preempt_curr(rq, p); |
1768 | task_rq_unlock(rq, &flags); | |
1da177e4 LT |
1769 | } |
1770 | ||
e107be36 AK |
1771 | #ifdef CONFIG_PREEMPT_NOTIFIERS |
1772 | ||
1773 | /** | |
421cee29 RD |
1774 | * preempt_notifier_register - tell me when current is being being preempted & rescheduled |
1775 | * @notifier: notifier struct to register | |
e107be36 AK |
1776 | */ |
1777 | void preempt_notifier_register(struct preempt_notifier *notifier) | |
1778 | { | |
1779 | hlist_add_head(¬ifier->link, ¤t->preempt_notifiers); | |
1780 | } | |
1781 | EXPORT_SYMBOL_GPL(preempt_notifier_register); | |
1782 | ||
1783 | /** | |
1784 | * preempt_notifier_unregister - no longer interested in preemption notifications | |
421cee29 | 1785 | * @notifier: notifier struct to unregister |
e107be36 AK |
1786 | * |
1787 | * This is safe to call from within a preemption notifier. | |
1788 | */ | |
1789 | void preempt_notifier_unregister(struct preempt_notifier *notifier) | |
1790 | { | |
1791 | hlist_del(¬ifier->link); | |
1792 | } | |
1793 | EXPORT_SYMBOL_GPL(preempt_notifier_unregister); | |
1794 | ||
1795 | static void fire_sched_in_preempt_notifiers(struct task_struct *curr) | |
1796 | { | |
1797 | struct preempt_notifier *notifier; | |
1798 | struct hlist_node *node; | |
1799 | ||
1800 | hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link) | |
1801 | notifier->ops->sched_in(notifier, raw_smp_processor_id()); | |
1802 | } | |
1803 | ||
1804 | static void | |
1805 | fire_sched_out_preempt_notifiers(struct task_struct *curr, | |
1806 | struct task_struct *next) | |
1807 | { | |
1808 | struct preempt_notifier *notifier; | |
1809 | struct hlist_node *node; | |
1810 | ||
1811 | hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link) | |
1812 | notifier->ops->sched_out(notifier, next); | |
1813 | } | |
1814 | ||
1815 | #else | |
1816 | ||
1817 | static void fire_sched_in_preempt_notifiers(struct task_struct *curr) | |
1818 | { | |
1819 | } | |
1820 | ||
1821 | static void | |
1822 | fire_sched_out_preempt_notifiers(struct task_struct *curr, | |
1823 | struct task_struct *next) | |
1824 | { | |
1825 | } | |
1826 | ||
1827 | #endif | |
1828 | ||
4866cde0 NP |
1829 | /** |
1830 | * prepare_task_switch - prepare to switch tasks | |
1831 | * @rq: the runqueue preparing to switch | |
421cee29 | 1832 | * @prev: the current task that is being switched out |
4866cde0 NP |
1833 | * @next: the task we are going to switch to. |
1834 | * | |
1835 | * This is called with the rq lock held and interrupts off. It must | |
1836 | * be paired with a subsequent finish_task_switch after the context | |
1837 | * switch. | |
1838 | * | |
1839 | * prepare_task_switch sets up locking and calls architecture specific | |
1840 | * hooks. | |
1841 | */ | |
e107be36 AK |
1842 | static inline void |
1843 | prepare_task_switch(struct rq *rq, struct task_struct *prev, | |
1844 | struct task_struct *next) | |
4866cde0 | 1845 | { |
e107be36 | 1846 | fire_sched_out_preempt_notifiers(prev, next); |
4866cde0 NP |
1847 | prepare_lock_switch(rq, next); |
1848 | prepare_arch_switch(next); | |
1849 | } | |
1850 | ||
1da177e4 LT |
1851 | /** |
1852 | * finish_task_switch - clean up after a task-switch | |
344babaa | 1853 | * @rq: runqueue associated with task-switch |
1da177e4 LT |
1854 | * @prev: the thread we just switched away from. |
1855 | * | |
4866cde0 NP |
1856 | * finish_task_switch must be called after the context switch, paired |
1857 | * with a prepare_task_switch call before the context switch. | |
1858 | * finish_task_switch will reconcile locking set up by prepare_task_switch, | |
1859 | * and do any other architecture-specific cleanup actions. | |
1da177e4 LT |
1860 | * |
1861 | * Note that we may have delayed dropping an mm in context_switch(). If | |
41a2d6cf | 1862 | * so, we finish that here outside of the runqueue lock. (Doing it |
1da177e4 LT |
1863 | * with the lock held can cause deadlocks; see schedule() for |
1864 | * details.) | |
1865 | */ | |
a9957449 | 1866 | static void finish_task_switch(struct rq *rq, struct task_struct *prev) |
1da177e4 LT |
1867 | __releases(rq->lock) |
1868 | { | |
1da177e4 | 1869 | struct mm_struct *mm = rq->prev_mm; |
55a101f8 | 1870 | long prev_state; |
1da177e4 LT |
1871 | |
1872 | rq->prev_mm = NULL; | |
1873 | ||
1874 | /* | |
1875 | * A task struct has one reference for the use as "current". | |
c394cc9f | 1876 | * If a task dies, then it sets TASK_DEAD in tsk->state and calls |
55a101f8 ON |
1877 | * schedule one last time. The schedule call will never return, and |
1878 | * the scheduled task must drop that reference. | |
c394cc9f | 1879 | * The test for TASK_DEAD must occur while the runqueue locks are |
1da177e4 LT |
1880 | * still held, otherwise prev could be scheduled on another cpu, die |
1881 | * there before we look at prev->state, and then the reference would | |
1882 | * be dropped twice. | |
1883 | * Manfred Spraul <manfred@colorfullife.com> | |
1884 | */ | |
55a101f8 | 1885 | prev_state = prev->state; |
4866cde0 NP |
1886 | finish_arch_switch(prev); |
1887 | finish_lock_switch(rq, prev); | |
e107be36 | 1888 | fire_sched_in_preempt_notifiers(current); |
1da177e4 LT |
1889 | if (mm) |
1890 | mmdrop(mm); | |
c394cc9f | 1891 | if (unlikely(prev_state == TASK_DEAD)) { |
c6fd91f0 | 1892 | /* |
1893 | * Remove function-return probe instances associated with this | |
1894 | * task and put them back on the free list. | |
9761eea8 | 1895 | */ |
c6fd91f0 | 1896 | kprobe_flush_task(prev); |
1da177e4 | 1897 | put_task_struct(prev); |
c6fd91f0 | 1898 | } |
1da177e4 LT |
1899 | } |
1900 | ||
1901 | /** | |
1902 | * schedule_tail - first thing a freshly forked thread must call. | |
1903 | * @prev: the thread we just switched away from. | |
1904 | */ | |
36c8b586 | 1905 | asmlinkage void schedule_tail(struct task_struct *prev) |
1da177e4 LT |
1906 | __releases(rq->lock) |
1907 | { | |
70b97a7f IM |
1908 | struct rq *rq = this_rq(); |
1909 | ||
4866cde0 NP |
1910 | finish_task_switch(rq, prev); |
1911 | #ifdef __ARCH_WANT_UNLOCKED_CTXSW | |
1912 | /* In this case, finish_task_switch does not reenable preemption */ | |
1913 | preempt_enable(); | |
1914 | #endif | |
1da177e4 | 1915 | if (current->set_child_tid) |
b488893a | 1916 | put_user(task_pid_vnr(current), current->set_child_tid); |
1da177e4 LT |
1917 | } |
1918 | ||
1919 | /* | |
1920 | * context_switch - switch to the new MM and the new | |
1921 | * thread's register state. | |
1922 | */ | |
dd41f596 | 1923 | static inline void |
70b97a7f | 1924 | context_switch(struct rq *rq, struct task_struct *prev, |
36c8b586 | 1925 | struct task_struct *next) |
1da177e4 | 1926 | { |
dd41f596 | 1927 | struct mm_struct *mm, *oldmm; |
1da177e4 | 1928 | |
e107be36 | 1929 | prepare_task_switch(rq, prev, next); |
dd41f596 IM |
1930 | mm = next->mm; |
1931 | oldmm = prev->active_mm; | |
9226d125 ZA |
1932 | /* |
1933 | * For paravirt, this is coupled with an exit in switch_to to | |
1934 | * combine the page table reload and the switch backend into | |
1935 | * one hypercall. | |
1936 | */ | |
1937 | arch_enter_lazy_cpu_mode(); | |
1938 | ||
dd41f596 | 1939 | if (unlikely(!mm)) { |
1da177e4 LT |
1940 | next->active_mm = oldmm; |
1941 | atomic_inc(&oldmm->mm_count); | |
1942 | enter_lazy_tlb(oldmm, next); | |
1943 | } else | |
1944 | switch_mm(oldmm, mm, next); | |
1945 | ||
dd41f596 | 1946 | if (unlikely(!prev->mm)) { |
1da177e4 | 1947 | prev->active_mm = NULL; |
1da177e4 LT |
1948 | rq->prev_mm = oldmm; |
1949 | } | |
3a5f5e48 IM |
1950 | /* |
1951 | * Since the runqueue lock will be released by the next | |
1952 | * task (which is an invalid locking op but in the case | |
1953 | * of the scheduler it's an obvious special-case), so we | |
1954 | * do an early lockdep release here: | |
1955 | */ | |
1956 | #ifndef __ARCH_WANT_UNLOCKED_CTXSW | |
8a25d5de | 1957 | spin_release(&rq->lock.dep_map, 1, _THIS_IP_); |
3a5f5e48 | 1958 | #endif |
1da177e4 LT |
1959 | |
1960 | /* Here we just switch the register state and the stack. */ | |
1961 | switch_to(prev, next, prev); | |
1962 | ||
dd41f596 IM |
1963 | barrier(); |
1964 | /* | |
1965 | * this_rq must be evaluated again because prev may have moved | |
1966 | * CPUs since it called schedule(), thus the 'rq' on its stack | |
1967 | * frame will be invalid. | |
1968 | */ | |
1969 | finish_task_switch(this_rq(), prev); | |
1da177e4 LT |
1970 | } |
1971 | ||
1972 | /* | |
1973 | * nr_running, nr_uninterruptible and nr_context_switches: | |
1974 | * | |
1975 | * externally visible scheduler statistics: current number of runnable | |
1976 | * threads, current number of uninterruptible-sleeping threads, total | |
1977 | * number of context switches performed since bootup. | |
1978 | */ | |
1979 | unsigned long nr_running(void) | |
1980 | { | |
1981 | unsigned long i, sum = 0; | |
1982 | ||
1983 | for_each_online_cpu(i) | |
1984 | sum += cpu_rq(i)->nr_running; | |
1985 | ||
1986 | return sum; | |
1987 | } | |
1988 | ||
1989 | unsigned long nr_uninterruptible(void) | |
1990 | { | |
1991 | unsigned long i, sum = 0; | |
1992 | ||
0a945022 | 1993 | for_each_possible_cpu(i) |
1da177e4 LT |
1994 | sum += cpu_rq(i)->nr_uninterruptible; |
1995 | ||
1996 | /* | |
1997 | * Since we read the counters lockless, it might be slightly | |
1998 | * inaccurate. Do not allow it to go below zero though: | |
1999 | */ | |
2000 | if (unlikely((long)sum < 0)) | |
2001 | sum = 0; | |
2002 | ||
2003 | return sum; | |
2004 | } | |
2005 | ||
2006 | unsigned long long nr_context_switches(void) | |
2007 | { | |
cc94abfc SR |
2008 | int i; |
2009 | unsigned long long sum = 0; | |
1da177e4 | 2010 | |
0a945022 | 2011 | for_each_possible_cpu(i) |
1da177e4 LT |
2012 | sum += cpu_rq(i)->nr_switches; |
2013 | ||
2014 | return sum; | |
2015 | } | |
2016 | ||
2017 | unsigned long nr_iowait(void) | |
2018 | { | |
2019 | unsigned long i, sum = 0; | |
2020 | ||
0a945022 | 2021 | for_each_possible_cpu(i) |
1da177e4 LT |
2022 | sum += atomic_read(&cpu_rq(i)->nr_iowait); |
2023 | ||
2024 | return sum; | |
2025 | } | |
2026 | ||
db1b1fef JS |
2027 | unsigned long nr_active(void) |
2028 | { | |
2029 | unsigned long i, running = 0, uninterruptible = 0; | |
2030 | ||
2031 | for_each_online_cpu(i) { | |
2032 | running += cpu_rq(i)->nr_running; | |
2033 | uninterruptible += cpu_rq(i)->nr_uninterruptible; | |
2034 | } | |
2035 | ||
2036 | if (unlikely((long)uninterruptible < 0)) | |
2037 | uninterruptible = 0; | |
2038 | ||
2039 | return running + uninterruptible; | |
2040 | } | |
2041 | ||
48f24c4d | 2042 | /* |
dd41f596 IM |
2043 | * Update rq->cpu_load[] statistics. This function is usually called every |
2044 | * scheduler tick (TICK_NSEC). | |
48f24c4d | 2045 | */ |
dd41f596 | 2046 | static void update_cpu_load(struct rq *this_rq) |
48f24c4d | 2047 | { |
495eca49 | 2048 | unsigned long this_load = this_rq->load.weight; |
dd41f596 IM |
2049 | int i, scale; |
2050 | ||
2051 | this_rq->nr_load_updates++; | |
dd41f596 IM |
2052 | |
2053 | /* Update our load: */ | |
2054 | for (i = 0, scale = 1; i < CPU_LOAD_IDX_MAX; i++, scale += scale) { | |
2055 | unsigned long old_load, new_load; | |
2056 | ||
2057 | /* scale is effectively 1 << i now, and >> i divides by scale */ | |
2058 | ||
2059 | old_load = this_rq->cpu_load[i]; | |
2060 | new_load = this_load; | |
a25707f3 IM |
2061 | /* |
2062 | * Round up the averaging division if load is increasing. This | |
2063 | * prevents us from getting stuck on 9 if the load is 10, for | |
2064 | * example. | |
2065 | */ | |
2066 | if (new_load > old_load) | |
2067 | new_load += scale-1; | |
dd41f596 IM |
2068 | this_rq->cpu_load[i] = (old_load*(scale-1) + new_load) >> i; |
2069 | } | |
48f24c4d IM |
2070 | } |
2071 | ||
dd41f596 IM |
2072 | #ifdef CONFIG_SMP |
2073 | ||
1da177e4 LT |
2074 | /* |
2075 | * double_rq_lock - safely lock two runqueues | |
2076 | * | |
2077 | * Note this does not disable interrupts like task_rq_lock, | |
2078 | * you need to do so manually before calling. | |
2079 | */ | |
70b97a7f | 2080 | static void double_rq_lock(struct rq *rq1, struct rq *rq2) |
1da177e4 LT |
2081 | __acquires(rq1->lock) |
2082 | __acquires(rq2->lock) | |
2083 | { | |
054b9108 | 2084 | BUG_ON(!irqs_disabled()); |
1da177e4 LT |
2085 | if (rq1 == rq2) { |
2086 | spin_lock(&rq1->lock); | |
2087 | __acquire(rq2->lock); /* Fake it out ;) */ | |
2088 | } else { | |
c96d145e | 2089 | if (rq1 < rq2) { |
1da177e4 LT |
2090 | spin_lock(&rq1->lock); |
2091 | spin_lock(&rq2->lock); | |
2092 | } else { | |
2093 | spin_lock(&rq2->lock); | |
2094 | spin_lock(&rq1->lock); | |
2095 | } | |
2096 | } | |
6e82a3be IM |
2097 | update_rq_clock(rq1); |
2098 | update_rq_clock(rq2); | |
1da177e4 LT |
2099 | } |
2100 | ||
2101 | /* | |
2102 | * double_rq_unlock - safely unlock two runqueues | |
2103 | * | |
2104 | * Note this does not restore interrupts like task_rq_unlock, | |
2105 | * you need to do so manually after calling. | |
2106 | */ | |
70b97a7f | 2107 | static void double_rq_unlock(struct rq *rq1, struct rq *rq2) |
1da177e4 LT |
2108 | __releases(rq1->lock) |
2109 | __releases(rq2->lock) | |
2110 | { | |
2111 | spin_unlock(&rq1->lock); | |
2112 | if (rq1 != rq2) | |
2113 | spin_unlock(&rq2->lock); | |
2114 | else | |
2115 | __release(rq2->lock); | |
2116 | } | |
2117 | ||
2118 | /* | |
2119 | * double_lock_balance - lock the busiest runqueue, this_rq is locked already. | |
2120 | */ | |
70b97a7f | 2121 | static void double_lock_balance(struct rq *this_rq, struct rq *busiest) |
1da177e4 LT |
2122 | __releases(this_rq->lock) |
2123 | __acquires(busiest->lock) | |
2124 | __acquires(this_rq->lock) | |
2125 | { | |
054b9108 KK |
2126 | if (unlikely(!irqs_disabled())) { |
2127 | /* printk() doesn't work good under rq->lock */ | |
2128 | spin_unlock(&this_rq->lock); | |
2129 | BUG_ON(1); | |
2130 | } | |
1da177e4 | 2131 | if (unlikely(!spin_trylock(&busiest->lock))) { |
c96d145e | 2132 | if (busiest < this_rq) { |
1da177e4 LT |
2133 | spin_unlock(&this_rq->lock); |
2134 | spin_lock(&busiest->lock); | |
2135 | spin_lock(&this_rq->lock); | |
2136 | } else | |
2137 | spin_lock(&busiest->lock); | |
2138 | } | |
2139 | } | |
2140 | ||
1da177e4 LT |
2141 | /* |
2142 | * If dest_cpu is allowed for this process, migrate the task to it. | |
2143 | * This is accomplished by forcing the cpu_allowed mask to only | |
41a2d6cf | 2144 | * allow dest_cpu, which will force the cpu onto dest_cpu. Then |
1da177e4 LT |
2145 | * the cpu_allowed mask is restored. |
2146 | */ | |
36c8b586 | 2147 | static void sched_migrate_task(struct task_struct *p, int dest_cpu) |
1da177e4 | 2148 | { |
70b97a7f | 2149 | struct migration_req req; |
1da177e4 | 2150 | unsigned long flags; |
70b97a7f | 2151 | struct rq *rq; |
1da177e4 LT |
2152 | |
2153 | rq = task_rq_lock(p, &flags); | |
2154 | if (!cpu_isset(dest_cpu, p->cpus_allowed) | |
2155 | || unlikely(cpu_is_offline(dest_cpu))) | |
2156 | goto out; | |
2157 | ||
2158 | /* force the process onto the specified CPU */ | |
2159 | if (migrate_task(p, dest_cpu, &req)) { | |
2160 | /* Need to wait for migration thread (might exit: take ref). */ | |
2161 | struct task_struct *mt = rq->migration_thread; | |
36c8b586 | 2162 | |
1da177e4 LT |
2163 | get_task_struct(mt); |
2164 | task_rq_unlock(rq, &flags); | |
2165 | wake_up_process(mt); | |
2166 | put_task_struct(mt); | |
2167 | wait_for_completion(&req.done); | |
36c8b586 | 2168 | |
1da177e4 LT |
2169 | return; |
2170 | } | |
2171 | out: | |
2172 | task_rq_unlock(rq, &flags); | |
2173 | } | |
2174 | ||
2175 | /* | |
476d139c NP |
2176 | * sched_exec - execve() is a valuable balancing opportunity, because at |
2177 | * this point the task has the smallest effective memory and cache footprint. | |
1da177e4 LT |
2178 | */ |
2179 | void sched_exec(void) | |
2180 | { | |
1da177e4 | 2181 | int new_cpu, this_cpu = get_cpu(); |
476d139c | 2182 | new_cpu = sched_balance_self(this_cpu, SD_BALANCE_EXEC); |
1da177e4 | 2183 | put_cpu(); |
476d139c NP |
2184 | if (new_cpu != this_cpu) |
2185 | sched_migrate_task(current, new_cpu); | |
1da177e4 LT |
2186 | } |
2187 | ||
2188 | /* | |
2189 | * pull_task - move a task from a remote runqueue to the local runqueue. | |
2190 | * Both runqueues must be locked. | |
2191 | */ | |
dd41f596 IM |
2192 | static void pull_task(struct rq *src_rq, struct task_struct *p, |
2193 | struct rq *this_rq, int this_cpu) | |
1da177e4 | 2194 | { |
2e1cb74a | 2195 | deactivate_task(src_rq, p, 0); |
1da177e4 | 2196 | set_task_cpu(p, this_cpu); |
dd41f596 | 2197 | activate_task(this_rq, p, 0); |
1da177e4 LT |
2198 | /* |
2199 | * Note that idle threads have a prio of MAX_PRIO, for this test | |
2200 | * to be always true for them. | |
2201 | */ | |
dd41f596 | 2202 | check_preempt_curr(this_rq, p); |
1da177e4 LT |
2203 | } |
2204 | ||
2205 | /* | |
2206 | * can_migrate_task - may task p from runqueue rq be migrated to this_cpu? | |
2207 | */ | |
858119e1 | 2208 | static |
70b97a7f | 2209 | int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu, |
d15bcfdb | 2210 | struct sched_domain *sd, enum cpu_idle_type idle, |
95cdf3b7 | 2211 | int *all_pinned) |
1da177e4 LT |
2212 | { |
2213 | /* | |
2214 | * We do not migrate tasks that are: | |
2215 | * 1) running (obviously), or | |
2216 | * 2) cannot be migrated to this CPU due to cpus_allowed, or | |
2217 | * 3) are cache-hot on their current CPU. | |
2218 | */ | |
cc367732 IM |
2219 | if (!cpu_isset(this_cpu, p->cpus_allowed)) { |
2220 | schedstat_inc(p, se.nr_failed_migrations_affine); | |
1da177e4 | 2221 | return 0; |
cc367732 | 2222 | } |
81026794 NP |
2223 | *all_pinned = 0; |
2224 | ||
cc367732 IM |
2225 | if (task_running(rq, p)) { |
2226 | schedstat_inc(p, se.nr_failed_migrations_running); | |
81026794 | 2227 | return 0; |
cc367732 | 2228 | } |
1da177e4 | 2229 | |
da84d961 IM |
2230 | /* |
2231 | * Aggressive migration if: | |
2232 | * 1) task is cache cold, or | |
2233 | * 2) too many balance attempts have failed. | |
2234 | */ | |
2235 | ||
6bc1665b IM |
2236 | if (!task_hot(p, rq->clock, sd) || |
2237 | sd->nr_balance_failed > sd->cache_nice_tries) { | |
da84d961 | 2238 | #ifdef CONFIG_SCHEDSTATS |
cc367732 | 2239 | if (task_hot(p, rq->clock, sd)) { |
da84d961 | 2240 | schedstat_inc(sd, lb_hot_gained[idle]); |
cc367732 IM |
2241 | schedstat_inc(p, se.nr_forced_migrations); |
2242 | } | |
da84d961 IM |
2243 | #endif |
2244 | return 1; | |
2245 | } | |
2246 | ||
cc367732 IM |
2247 | if (task_hot(p, rq->clock, sd)) { |
2248 | schedstat_inc(p, se.nr_failed_migrations_hot); | |
da84d961 | 2249 | return 0; |
cc367732 | 2250 | } |
1da177e4 LT |
2251 | return 1; |
2252 | } | |
2253 | ||
e1d1484f PW |
2254 | static unsigned long |
2255 | balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
2256 | unsigned long max_load_move, struct sched_domain *sd, | |
2257 | enum cpu_idle_type idle, int *all_pinned, | |
2258 | int *this_best_prio, struct rq_iterator *iterator) | |
1da177e4 | 2259 | { |
b82d9fdd | 2260 | int loops = 0, pulled = 0, pinned = 0, skip_for_load; |
dd41f596 IM |
2261 | struct task_struct *p; |
2262 | long rem_load_move = max_load_move; | |
1da177e4 | 2263 | |
e1d1484f | 2264 | if (max_load_move == 0) |
1da177e4 LT |
2265 | goto out; |
2266 | ||
81026794 NP |
2267 | pinned = 1; |
2268 | ||
1da177e4 | 2269 | /* |
dd41f596 | 2270 | * Start the load-balancing iterator: |
1da177e4 | 2271 | */ |
dd41f596 IM |
2272 | p = iterator->start(iterator->arg); |
2273 | next: | |
b82d9fdd | 2274 | if (!p || loops++ > sysctl_sched_nr_migrate) |
1da177e4 | 2275 | goto out; |
50ddd969 | 2276 | /* |
b82d9fdd | 2277 | * To help distribute high priority tasks across CPUs we don't |
50ddd969 PW |
2278 | * skip a task if it will be the highest priority task (i.e. smallest |
2279 | * prio value) on its new queue regardless of its load weight | |
2280 | */ | |
dd41f596 IM |
2281 | skip_for_load = (p->se.load.weight >> 1) > rem_load_move + |
2282 | SCHED_LOAD_SCALE_FUZZ; | |
a4ac01c3 | 2283 | if ((skip_for_load && p->prio >= *this_best_prio) || |
dd41f596 | 2284 | !can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) { |
dd41f596 IM |
2285 | p = iterator->next(iterator->arg); |
2286 | goto next; | |
1da177e4 LT |
2287 | } |
2288 | ||
dd41f596 | 2289 | pull_task(busiest, p, this_rq, this_cpu); |
1da177e4 | 2290 | pulled++; |
dd41f596 | 2291 | rem_load_move -= p->se.load.weight; |
1da177e4 | 2292 | |
2dd73a4f | 2293 | /* |
b82d9fdd | 2294 | * We only want to steal up to the prescribed amount of weighted load. |
2dd73a4f | 2295 | */ |
e1d1484f | 2296 | if (rem_load_move > 0) { |
a4ac01c3 PW |
2297 | if (p->prio < *this_best_prio) |
2298 | *this_best_prio = p->prio; | |
dd41f596 IM |
2299 | p = iterator->next(iterator->arg); |
2300 | goto next; | |
1da177e4 LT |
2301 | } |
2302 | out: | |
2303 | /* | |
e1d1484f | 2304 | * Right now, this is one of only two places pull_task() is called, |
1da177e4 LT |
2305 | * so we can safely collect pull_task() stats here rather than |
2306 | * inside pull_task(). | |
2307 | */ | |
2308 | schedstat_add(sd, lb_gained[idle], pulled); | |
81026794 NP |
2309 | |
2310 | if (all_pinned) | |
2311 | *all_pinned = pinned; | |
e1d1484f PW |
2312 | |
2313 | return max_load_move - rem_load_move; | |
1da177e4 LT |
2314 | } |
2315 | ||
dd41f596 | 2316 | /* |
43010659 PW |
2317 | * move_tasks tries to move up to max_load_move weighted load from busiest to |
2318 | * this_rq, as part of a balancing operation within domain "sd". | |
2319 | * Returns 1 if successful and 0 otherwise. | |
dd41f596 IM |
2320 | * |
2321 | * Called with both runqueues locked. | |
2322 | */ | |
2323 | static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
43010659 | 2324 | unsigned long max_load_move, |
dd41f596 IM |
2325 | struct sched_domain *sd, enum cpu_idle_type idle, |
2326 | int *all_pinned) | |
2327 | { | |
5522d5d5 | 2328 | const struct sched_class *class = sched_class_highest; |
43010659 | 2329 | unsigned long total_load_moved = 0; |
a4ac01c3 | 2330 | int this_best_prio = this_rq->curr->prio; |
dd41f596 IM |
2331 | |
2332 | do { | |
43010659 PW |
2333 | total_load_moved += |
2334 | class->load_balance(this_rq, this_cpu, busiest, | |
e1d1484f | 2335 | max_load_move - total_load_moved, |
a4ac01c3 | 2336 | sd, idle, all_pinned, &this_best_prio); |
dd41f596 | 2337 | class = class->next; |
43010659 | 2338 | } while (class && max_load_move > total_load_moved); |
dd41f596 | 2339 | |
43010659 PW |
2340 | return total_load_moved > 0; |
2341 | } | |
2342 | ||
e1d1484f PW |
2343 | static int |
2344 | iter_move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
2345 | struct sched_domain *sd, enum cpu_idle_type idle, | |
2346 | struct rq_iterator *iterator) | |
2347 | { | |
2348 | struct task_struct *p = iterator->start(iterator->arg); | |
2349 | int pinned = 0; | |
2350 | ||
2351 | while (p) { | |
2352 | if (can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) { | |
2353 | pull_task(busiest, p, this_rq, this_cpu); | |
2354 | /* | |
2355 | * Right now, this is only the second place pull_task() | |
2356 | * is called, so we can safely collect pull_task() | |
2357 | * stats here rather than inside pull_task(). | |
2358 | */ | |
2359 | schedstat_inc(sd, lb_gained[idle]); | |
2360 | ||
2361 | return 1; | |
2362 | } | |
2363 | p = iterator->next(iterator->arg); | |
2364 | } | |
2365 | ||
2366 | return 0; | |
2367 | } | |
2368 | ||
43010659 PW |
2369 | /* |
2370 | * move_one_task tries to move exactly one task from busiest to this_rq, as | |
2371 | * part of active balancing operations within "domain". | |
2372 | * Returns 1 if successful and 0 otherwise. | |
2373 | * | |
2374 | * Called with both runqueues locked. | |
2375 | */ | |
2376 | static int move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
2377 | struct sched_domain *sd, enum cpu_idle_type idle) | |
2378 | { | |
5522d5d5 | 2379 | const struct sched_class *class; |
43010659 PW |
2380 | |
2381 | for (class = sched_class_highest; class; class = class->next) | |
e1d1484f | 2382 | if (class->move_one_task(this_rq, this_cpu, busiest, sd, idle)) |
43010659 PW |
2383 | return 1; |
2384 | ||
2385 | return 0; | |
dd41f596 IM |
2386 | } |
2387 | ||
1da177e4 LT |
2388 | /* |
2389 | * find_busiest_group finds and returns the busiest CPU group within the | |
48f24c4d IM |
2390 | * domain. It calculates and returns the amount of weighted load which |
2391 | * should be moved to restore balance via the imbalance parameter. | |
1da177e4 LT |
2392 | */ |
2393 | static struct sched_group * | |
2394 | find_busiest_group(struct sched_domain *sd, int this_cpu, | |
dd41f596 IM |
2395 | unsigned long *imbalance, enum cpu_idle_type idle, |
2396 | int *sd_idle, cpumask_t *cpus, int *balance) | |
1da177e4 LT |
2397 | { |
2398 | struct sched_group *busiest = NULL, *this = NULL, *group = sd->groups; | |
2399 | unsigned long max_load, avg_load, total_load, this_load, total_pwr; | |
0c117f1b | 2400 | unsigned long max_pull; |
2dd73a4f PW |
2401 | unsigned long busiest_load_per_task, busiest_nr_running; |
2402 | unsigned long this_load_per_task, this_nr_running; | |
908a7c1b | 2403 | int load_idx, group_imb = 0; |
5c45bf27 SS |
2404 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) |
2405 | int power_savings_balance = 1; | |
2406 | unsigned long leader_nr_running = 0, min_load_per_task = 0; | |
2407 | unsigned long min_nr_running = ULONG_MAX; | |
2408 | struct sched_group *group_min = NULL, *group_leader = NULL; | |
2409 | #endif | |
1da177e4 LT |
2410 | |
2411 | max_load = this_load = total_load = total_pwr = 0; | |
2dd73a4f PW |
2412 | busiest_load_per_task = busiest_nr_running = 0; |
2413 | this_load_per_task = this_nr_running = 0; | |
d15bcfdb | 2414 | if (idle == CPU_NOT_IDLE) |
7897986b | 2415 | load_idx = sd->busy_idx; |
d15bcfdb | 2416 | else if (idle == CPU_NEWLY_IDLE) |
7897986b NP |
2417 | load_idx = sd->newidle_idx; |
2418 | else | |
2419 | load_idx = sd->idle_idx; | |
1da177e4 LT |
2420 | |
2421 | do { | |
908a7c1b | 2422 | unsigned long load, group_capacity, max_cpu_load, min_cpu_load; |
1da177e4 LT |
2423 | int local_group; |
2424 | int i; | |
908a7c1b | 2425 | int __group_imb = 0; |
783609c6 | 2426 | unsigned int balance_cpu = -1, first_idle_cpu = 0; |
2dd73a4f | 2427 | unsigned long sum_nr_running, sum_weighted_load; |
1da177e4 LT |
2428 | |
2429 | local_group = cpu_isset(this_cpu, group->cpumask); | |
2430 | ||
783609c6 SS |
2431 | if (local_group) |
2432 | balance_cpu = first_cpu(group->cpumask); | |
2433 | ||
1da177e4 | 2434 | /* Tally up the load of all CPUs in the group */ |
2dd73a4f | 2435 | sum_weighted_load = sum_nr_running = avg_load = 0; |
908a7c1b KC |
2436 | max_cpu_load = 0; |
2437 | min_cpu_load = ~0UL; | |
1da177e4 LT |
2438 | |
2439 | for_each_cpu_mask(i, group->cpumask) { | |
0a2966b4 CL |
2440 | struct rq *rq; |
2441 | ||
2442 | if (!cpu_isset(i, *cpus)) | |
2443 | continue; | |
2444 | ||
2445 | rq = cpu_rq(i); | |
2dd73a4f | 2446 | |
9439aab8 | 2447 | if (*sd_idle && rq->nr_running) |
5969fe06 NP |
2448 | *sd_idle = 0; |
2449 | ||
1da177e4 | 2450 | /* Bias balancing toward cpus of our domain */ |
783609c6 SS |
2451 | if (local_group) { |
2452 | if (idle_cpu(i) && !first_idle_cpu) { | |
2453 | first_idle_cpu = 1; | |
2454 | balance_cpu = i; | |
2455 | } | |
2456 | ||
a2000572 | 2457 | load = target_load(i, load_idx); |
908a7c1b | 2458 | } else { |
a2000572 | 2459 | load = source_load(i, load_idx); |
908a7c1b KC |
2460 | if (load > max_cpu_load) |
2461 | max_cpu_load = load; | |
2462 | if (min_cpu_load > load) | |
2463 | min_cpu_load = load; | |
2464 | } | |
1da177e4 LT |
2465 | |
2466 | avg_load += load; | |
2dd73a4f | 2467 | sum_nr_running += rq->nr_running; |
dd41f596 | 2468 | sum_weighted_load += weighted_cpuload(i); |
1da177e4 LT |
2469 | } |
2470 | ||
783609c6 SS |
2471 | /* |
2472 | * First idle cpu or the first cpu(busiest) in this sched group | |
2473 | * is eligible for doing load balancing at this and above | |
9439aab8 SS |
2474 | * domains. In the newly idle case, we will allow all the cpu's |
2475 | * to do the newly idle load balance. | |
783609c6 | 2476 | */ |
9439aab8 SS |
2477 | if (idle != CPU_NEWLY_IDLE && local_group && |
2478 | balance_cpu != this_cpu && balance) { | |
783609c6 SS |
2479 | *balance = 0; |
2480 | goto ret; | |
2481 | } | |
2482 | ||
1da177e4 | 2483 | total_load += avg_load; |
5517d86b | 2484 | total_pwr += group->__cpu_power; |
1da177e4 LT |
2485 | |
2486 | /* Adjust by relative CPU power of the group */ | |
5517d86b ED |
2487 | avg_load = sg_div_cpu_power(group, |
2488 | avg_load * SCHED_LOAD_SCALE); | |
1da177e4 | 2489 | |
908a7c1b KC |
2490 | if ((max_cpu_load - min_cpu_load) > SCHED_LOAD_SCALE) |
2491 | __group_imb = 1; | |
2492 | ||
5517d86b | 2493 | group_capacity = group->__cpu_power / SCHED_LOAD_SCALE; |
5c45bf27 | 2494 | |
1da177e4 LT |
2495 | if (local_group) { |
2496 | this_load = avg_load; | |
2497 | this = group; | |
2dd73a4f PW |
2498 | this_nr_running = sum_nr_running; |
2499 | this_load_per_task = sum_weighted_load; | |
2500 | } else if (avg_load > max_load && | |
908a7c1b | 2501 | (sum_nr_running > group_capacity || __group_imb)) { |
1da177e4 LT |
2502 | max_load = avg_load; |
2503 | busiest = group; | |
2dd73a4f PW |
2504 | busiest_nr_running = sum_nr_running; |
2505 | busiest_load_per_task = sum_weighted_load; | |
908a7c1b | 2506 | group_imb = __group_imb; |
1da177e4 | 2507 | } |
5c45bf27 SS |
2508 | |
2509 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) | |
2510 | /* | |
2511 | * Busy processors will not participate in power savings | |
2512 | * balance. | |
2513 | */ | |
dd41f596 IM |
2514 | if (idle == CPU_NOT_IDLE || |
2515 | !(sd->flags & SD_POWERSAVINGS_BALANCE)) | |
2516 | goto group_next; | |
5c45bf27 SS |
2517 | |
2518 | /* | |
2519 | * If the local group is idle or completely loaded | |
2520 | * no need to do power savings balance at this domain | |
2521 | */ | |
2522 | if (local_group && (this_nr_running >= group_capacity || | |
2523 | !this_nr_running)) | |
2524 | power_savings_balance = 0; | |
2525 | ||
dd41f596 | 2526 | /* |
5c45bf27 SS |
2527 | * If a group is already running at full capacity or idle, |
2528 | * don't include that group in power savings calculations | |
dd41f596 IM |
2529 | */ |
2530 | if (!power_savings_balance || sum_nr_running >= group_capacity | |
5c45bf27 | 2531 | || !sum_nr_running) |
dd41f596 | 2532 | goto group_next; |
5c45bf27 | 2533 | |
dd41f596 | 2534 | /* |
5c45bf27 | 2535 | * Calculate the group which has the least non-idle load. |
dd41f596 IM |
2536 | * This is the group from where we need to pick up the load |
2537 | * for saving power | |
2538 | */ | |
2539 | if ((sum_nr_running < min_nr_running) || | |
2540 | (sum_nr_running == min_nr_running && | |
5c45bf27 SS |
2541 | first_cpu(group->cpumask) < |
2542 | first_cpu(group_min->cpumask))) { | |
dd41f596 IM |
2543 | group_min = group; |
2544 | min_nr_running = sum_nr_running; | |
5c45bf27 SS |
2545 | min_load_per_task = sum_weighted_load / |
2546 | sum_nr_running; | |
dd41f596 | 2547 | } |
5c45bf27 | 2548 | |
dd41f596 | 2549 | /* |
5c45bf27 | 2550 | * Calculate the group which is almost near its |
dd41f596 IM |
2551 | * capacity but still has some space to pick up some load |
2552 | * from other group and save more power | |
2553 | */ | |
2554 | if (sum_nr_running <= group_capacity - 1) { | |
2555 | if (sum_nr_running > leader_nr_running || | |
2556 | (sum_nr_running == leader_nr_running && | |
2557 | first_cpu(group->cpumask) > | |
2558 | first_cpu(group_leader->cpumask))) { | |
2559 | group_leader = group; | |
2560 | leader_nr_running = sum_nr_running; | |
2561 | } | |
48f24c4d | 2562 | } |
5c45bf27 SS |
2563 | group_next: |
2564 | #endif | |
1da177e4 LT |
2565 | group = group->next; |
2566 | } while (group != sd->groups); | |
2567 | ||
2dd73a4f | 2568 | if (!busiest || this_load >= max_load || busiest_nr_running == 0) |
1da177e4 LT |
2569 | goto out_balanced; |
2570 | ||
2571 | avg_load = (SCHED_LOAD_SCALE * total_load) / total_pwr; | |
2572 | ||
2573 | if (this_load >= avg_load || | |
2574 | 100*max_load <= sd->imbalance_pct*this_load) | |
2575 | goto out_balanced; | |
2576 | ||
2dd73a4f | 2577 | busiest_load_per_task /= busiest_nr_running; |
908a7c1b KC |
2578 | if (group_imb) |
2579 | busiest_load_per_task = min(busiest_load_per_task, avg_load); | |
2580 | ||
1da177e4 LT |
2581 | /* |
2582 | * We're trying to get all the cpus to the average_load, so we don't | |
2583 | * want to push ourselves above the average load, nor do we wish to | |
2584 | * reduce the max loaded cpu below the average load, as either of these | |
2585 | * actions would just result in more rebalancing later, and ping-pong | |
2586 | * tasks around. Thus we look for the minimum possible imbalance. | |
2587 | * Negative imbalances (*we* are more loaded than anyone else) will | |
2588 | * be counted as no imbalance for these purposes -- we can't fix that | |
41a2d6cf | 2589 | * by pulling tasks to us. Be careful of negative numbers as they'll |
1da177e4 LT |
2590 | * appear as very large values with unsigned longs. |
2591 | */ | |
2dd73a4f PW |
2592 | if (max_load <= busiest_load_per_task) |
2593 | goto out_balanced; | |
2594 | ||
2595 | /* | |
2596 | * In the presence of smp nice balancing, certain scenarios can have | |
2597 | * max load less than avg load(as we skip the groups at or below | |
2598 | * its cpu_power, while calculating max_load..) | |
2599 | */ | |
2600 | if (max_load < avg_load) { | |
2601 | *imbalance = 0; | |
2602 | goto small_imbalance; | |
2603 | } | |
0c117f1b SS |
2604 | |
2605 | /* Don't want to pull so many tasks that a group would go idle */ | |
2dd73a4f | 2606 | max_pull = min(max_load - avg_load, max_load - busiest_load_per_task); |
0c117f1b | 2607 | |
1da177e4 | 2608 | /* How much load to actually move to equalise the imbalance */ |
5517d86b ED |
2609 | *imbalance = min(max_pull * busiest->__cpu_power, |
2610 | (avg_load - this_load) * this->__cpu_power) | |
1da177e4 LT |
2611 | / SCHED_LOAD_SCALE; |
2612 | ||
2dd73a4f PW |
2613 | /* |
2614 | * if *imbalance is less than the average load per runnable task | |
2615 | * there is no gaurantee that any tasks will be moved so we'll have | |
2616 | * a think about bumping its value to force at least one task to be | |
2617 | * moved | |
2618 | */ | |
7fd0d2dd | 2619 | if (*imbalance < busiest_load_per_task) { |
48f24c4d | 2620 | unsigned long tmp, pwr_now, pwr_move; |
2dd73a4f PW |
2621 | unsigned int imbn; |
2622 | ||
2623 | small_imbalance: | |
2624 | pwr_move = pwr_now = 0; | |
2625 | imbn = 2; | |
2626 | if (this_nr_running) { | |
2627 | this_load_per_task /= this_nr_running; | |
2628 | if (busiest_load_per_task > this_load_per_task) | |
2629 | imbn = 1; | |
2630 | } else | |
2631 | this_load_per_task = SCHED_LOAD_SCALE; | |
1da177e4 | 2632 | |
dd41f596 IM |
2633 | if (max_load - this_load + SCHED_LOAD_SCALE_FUZZ >= |
2634 | busiest_load_per_task * imbn) { | |
2dd73a4f | 2635 | *imbalance = busiest_load_per_task; |
1da177e4 LT |
2636 | return busiest; |
2637 | } | |
2638 | ||
2639 | /* | |
2640 | * OK, we don't have enough imbalance to justify moving tasks, | |
2641 | * however we may be able to increase total CPU power used by | |
2642 | * moving them. | |
2643 | */ | |
2644 | ||
5517d86b ED |
2645 | pwr_now += busiest->__cpu_power * |
2646 | min(busiest_load_per_task, max_load); | |
2647 | pwr_now += this->__cpu_power * | |
2648 | min(this_load_per_task, this_load); | |
1da177e4 LT |
2649 | pwr_now /= SCHED_LOAD_SCALE; |
2650 | ||
2651 | /* Amount of load we'd subtract */ | |
5517d86b ED |
2652 | tmp = sg_div_cpu_power(busiest, |
2653 | busiest_load_per_task * SCHED_LOAD_SCALE); | |
1da177e4 | 2654 | if (max_load > tmp) |
5517d86b | 2655 | pwr_move += busiest->__cpu_power * |
2dd73a4f | 2656 | min(busiest_load_per_task, max_load - tmp); |
1da177e4 LT |
2657 | |
2658 | /* Amount of load we'd add */ | |
5517d86b | 2659 | if (max_load * busiest->__cpu_power < |
33859f7f | 2660 | busiest_load_per_task * SCHED_LOAD_SCALE) |
5517d86b ED |
2661 | tmp = sg_div_cpu_power(this, |
2662 | max_load * busiest->__cpu_power); | |
1da177e4 | 2663 | else |
5517d86b ED |
2664 | tmp = sg_div_cpu_power(this, |
2665 | busiest_load_per_task * SCHED_LOAD_SCALE); | |
2666 | pwr_move += this->__cpu_power * | |
2667 | min(this_load_per_task, this_load + tmp); | |
1da177e4 LT |
2668 | pwr_move /= SCHED_LOAD_SCALE; |
2669 | ||
2670 | /* Move if we gain throughput */ | |
7fd0d2dd SS |
2671 | if (pwr_move > pwr_now) |
2672 | *imbalance = busiest_load_per_task; | |
1da177e4 LT |
2673 | } |
2674 | ||
1da177e4 LT |
2675 | return busiest; |
2676 | ||
2677 | out_balanced: | |
5c45bf27 | 2678 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) |
d15bcfdb | 2679 | if (idle == CPU_NOT_IDLE || !(sd->flags & SD_POWERSAVINGS_BALANCE)) |
5c45bf27 | 2680 | goto ret; |
1da177e4 | 2681 | |
5c45bf27 SS |
2682 | if (this == group_leader && group_leader != group_min) { |
2683 | *imbalance = min_load_per_task; | |
2684 | return group_min; | |
2685 | } | |
5c45bf27 | 2686 | #endif |
783609c6 | 2687 | ret: |
1da177e4 LT |
2688 | *imbalance = 0; |
2689 | return NULL; | |
2690 | } | |
2691 | ||
2692 | /* | |
2693 | * find_busiest_queue - find the busiest runqueue among the cpus in group. | |
2694 | */ | |
70b97a7f | 2695 | static struct rq * |
d15bcfdb | 2696 | find_busiest_queue(struct sched_group *group, enum cpu_idle_type idle, |
0a2966b4 | 2697 | unsigned long imbalance, cpumask_t *cpus) |
1da177e4 | 2698 | { |
70b97a7f | 2699 | struct rq *busiest = NULL, *rq; |
2dd73a4f | 2700 | unsigned long max_load = 0; |
1da177e4 LT |
2701 | int i; |
2702 | ||
2703 | for_each_cpu_mask(i, group->cpumask) { | |
dd41f596 | 2704 | unsigned long wl; |
0a2966b4 CL |
2705 | |
2706 | if (!cpu_isset(i, *cpus)) | |
2707 | continue; | |
2708 | ||
48f24c4d | 2709 | rq = cpu_rq(i); |
dd41f596 | 2710 | wl = weighted_cpuload(i); |
2dd73a4f | 2711 | |
dd41f596 | 2712 | if (rq->nr_running == 1 && wl > imbalance) |
2dd73a4f | 2713 | continue; |
1da177e4 | 2714 | |
dd41f596 IM |
2715 | if (wl > max_load) { |
2716 | max_load = wl; | |
48f24c4d | 2717 | busiest = rq; |
1da177e4 LT |
2718 | } |
2719 | } | |
2720 | ||
2721 | return busiest; | |
2722 | } | |
2723 | ||
77391d71 NP |
2724 | /* |
2725 | * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but | |
2726 | * so long as it is large enough. | |
2727 | */ | |
2728 | #define MAX_PINNED_INTERVAL 512 | |
2729 | ||
1da177e4 LT |
2730 | /* |
2731 | * Check this_cpu to ensure it is balanced within domain. Attempt to move | |
2732 | * tasks if there is an imbalance. | |
1da177e4 | 2733 | */ |
70b97a7f | 2734 | static int load_balance(int this_cpu, struct rq *this_rq, |
d15bcfdb | 2735 | struct sched_domain *sd, enum cpu_idle_type idle, |
783609c6 | 2736 | int *balance) |
1da177e4 | 2737 | { |
43010659 | 2738 | int ld_moved, all_pinned = 0, active_balance = 0, sd_idle = 0; |
1da177e4 | 2739 | struct sched_group *group; |
1da177e4 | 2740 | unsigned long imbalance; |
70b97a7f | 2741 | struct rq *busiest; |
0a2966b4 | 2742 | cpumask_t cpus = CPU_MASK_ALL; |
fe2eea3f | 2743 | unsigned long flags; |
5969fe06 | 2744 | |
89c4710e SS |
2745 | /* |
2746 | * When power savings policy is enabled for the parent domain, idle | |
2747 | * sibling can pick up load irrespective of busy siblings. In this case, | |
dd41f596 | 2748 | * let the state of idle sibling percolate up as CPU_IDLE, instead of |
d15bcfdb | 2749 | * portraying it as CPU_NOT_IDLE. |
89c4710e | 2750 | */ |
d15bcfdb | 2751 | if (idle != CPU_NOT_IDLE && sd->flags & SD_SHARE_CPUPOWER && |
89c4710e | 2752 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
5969fe06 | 2753 | sd_idle = 1; |
1da177e4 | 2754 | |
2d72376b | 2755 | schedstat_inc(sd, lb_count[idle]); |
1da177e4 | 2756 | |
0a2966b4 CL |
2757 | redo: |
2758 | group = find_busiest_group(sd, this_cpu, &imbalance, idle, &sd_idle, | |
783609c6 SS |
2759 | &cpus, balance); |
2760 | ||
06066714 | 2761 | if (*balance == 0) |
783609c6 | 2762 | goto out_balanced; |
783609c6 | 2763 | |
1da177e4 LT |
2764 | if (!group) { |
2765 | schedstat_inc(sd, lb_nobusyg[idle]); | |
2766 | goto out_balanced; | |
2767 | } | |
2768 | ||
0a2966b4 | 2769 | busiest = find_busiest_queue(group, idle, imbalance, &cpus); |
1da177e4 LT |
2770 | if (!busiest) { |
2771 | schedstat_inc(sd, lb_nobusyq[idle]); | |
2772 | goto out_balanced; | |
2773 | } | |
2774 | ||
db935dbd | 2775 | BUG_ON(busiest == this_rq); |
1da177e4 LT |
2776 | |
2777 | schedstat_add(sd, lb_imbalance[idle], imbalance); | |
2778 | ||
43010659 | 2779 | ld_moved = 0; |
1da177e4 LT |
2780 | if (busiest->nr_running > 1) { |
2781 | /* | |
2782 | * Attempt to move tasks. If find_busiest_group has found | |
2783 | * an imbalance but busiest->nr_running <= 1, the group is | |
43010659 | 2784 | * still unbalanced. ld_moved simply stays zero, so it is |
1da177e4 LT |
2785 | * correctly treated as an imbalance. |
2786 | */ | |
fe2eea3f | 2787 | local_irq_save(flags); |
e17224bf | 2788 | double_rq_lock(this_rq, busiest); |
43010659 | 2789 | ld_moved = move_tasks(this_rq, this_cpu, busiest, |
48f24c4d | 2790 | imbalance, sd, idle, &all_pinned); |
e17224bf | 2791 | double_rq_unlock(this_rq, busiest); |
fe2eea3f | 2792 | local_irq_restore(flags); |
81026794 | 2793 | |
46cb4b7c SS |
2794 | /* |
2795 | * some other cpu did the load balance for us. | |
2796 | */ | |
43010659 | 2797 | if (ld_moved && this_cpu != smp_processor_id()) |
46cb4b7c SS |
2798 | resched_cpu(this_cpu); |
2799 | ||
81026794 | 2800 | /* All tasks on this runqueue were pinned by CPU affinity */ |
0a2966b4 CL |
2801 | if (unlikely(all_pinned)) { |
2802 | cpu_clear(cpu_of(busiest), cpus); | |
2803 | if (!cpus_empty(cpus)) | |
2804 | goto redo; | |
81026794 | 2805 | goto out_balanced; |
0a2966b4 | 2806 | } |
1da177e4 | 2807 | } |
81026794 | 2808 | |
43010659 | 2809 | if (!ld_moved) { |
1da177e4 LT |
2810 | schedstat_inc(sd, lb_failed[idle]); |
2811 | sd->nr_balance_failed++; | |
2812 | ||
2813 | if (unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2)) { | |
1da177e4 | 2814 | |
fe2eea3f | 2815 | spin_lock_irqsave(&busiest->lock, flags); |
fa3b6ddc SS |
2816 | |
2817 | /* don't kick the migration_thread, if the curr | |
2818 | * task on busiest cpu can't be moved to this_cpu | |
2819 | */ | |
2820 | if (!cpu_isset(this_cpu, busiest->curr->cpus_allowed)) { | |
fe2eea3f | 2821 | spin_unlock_irqrestore(&busiest->lock, flags); |
fa3b6ddc SS |
2822 | all_pinned = 1; |
2823 | goto out_one_pinned; | |
2824 | } | |
2825 | ||
1da177e4 LT |
2826 | if (!busiest->active_balance) { |
2827 | busiest->active_balance = 1; | |
2828 | busiest->push_cpu = this_cpu; | |
81026794 | 2829 | active_balance = 1; |
1da177e4 | 2830 | } |
fe2eea3f | 2831 | spin_unlock_irqrestore(&busiest->lock, flags); |
81026794 | 2832 | if (active_balance) |
1da177e4 LT |
2833 | wake_up_process(busiest->migration_thread); |
2834 | ||
2835 | /* | |
2836 | * We've kicked active balancing, reset the failure | |
2837 | * counter. | |
2838 | */ | |
39507451 | 2839 | sd->nr_balance_failed = sd->cache_nice_tries+1; |
1da177e4 | 2840 | } |
81026794 | 2841 | } else |
1da177e4 LT |
2842 | sd->nr_balance_failed = 0; |
2843 | ||
81026794 | 2844 | if (likely(!active_balance)) { |
1da177e4 LT |
2845 | /* We were unbalanced, so reset the balancing interval */ |
2846 | sd->balance_interval = sd->min_interval; | |
81026794 NP |
2847 | } else { |
2848 | /* | |
2849 | * If we've begun active balancing, start to back off. This | |
2850 | * case may not be covered by the all_pinned logic if there | |
2851 | * is only 1 task on the busy runqueue (because we don't call | |
2852 | * move_tasks). | |
2853 | */ | |
2854 | if (sd->balance_interval < sd->max_interval) | |
2855 | sd->balance_interval *= 2; | |
1da177e4 LT |
2856 | } |
2857 | ||
43010659 | 2858 | if (!ld_moved && !sd_idle && sd->flags & SD_SHARE_CPUPOWER && |
89c4710e | 2859 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
5969fe06 | 2860 | return -1; |
43010659 | 2861 | return ld_moved; |
1da177e4 LT |
2862 | |
2863 | out_balanced: | |
1da177e4 LT |
2864 | schedstat_inc(sd, lb_balanced[idle]); |
2865 | ||
16cfb1c0 | 2866 | sd->nr_balance_failed = 0; |
fa3b6ddc SS |
2867 | |
2868 | out_one_pinned: | |
1da177e4 | 2869 | /* tune up the balancing interval */ |
77391d71 NP |
2870 | if ((all_pinned && sd->balance_interval < MAX_PINNED_INTERVAL) || |
2871 | (sd->balance_interval < sd->max_interval)) | |
1da177e4 LT |
2872 | sd->balance_interval *= 2; |
2873 | ||
48f24c4d | 2874 | if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && |
89c4710e | 2875 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
5969fe06 | 2876 | return -1; |
1da177e4 LT |
2877 | return 0; |
2878 | } | |
2879 | ||
2880 | /* | |
2881 | * Check this_cpu to ensure it is balanced within domain. Attempt to move | |
2882 | * tasks if there is an imbalance. | |
2883 | * | |
d15bcfdb | 2884 | * Called from schedule when this_rq is about to become idle (CPU_NEWLY_IDLE). |
1da177e4 LT |
2885 | * this_rq is locked. |
2886 | */ | |
48f24c4d | 2887 | static int |
70b97a7f | 2888 | load_balance_newidle(int this_cpu, struct rq *this_rq, struct sched_domain *sd) |
1da177e4 LT |
2889 | { |
2890 | struct sched_group *group; | |
70b97a7f | 2891 | struct rq *busiest = NULL; |
1da177e4 | 2892 | unsigned long imbalance; |
43010659 | 2893 | int ld_moved = 0; |
5969fe06 | 2894 | int sd_idle = 0; |
969bb4e4 | 2895 | int all_pinned = 0; |
0a2966b4 | 2896 | cpumask_t cpus = CPU_MASK_ALL; |
5969fe06 | 2897 | |
89c4710e SS |
2898 | /* |
2899 | * When power savings policy is enabled for the parent domain, idle | |
2900 | * sibling can pick up load irrespective of busy siblings. In this case, | |
2901 | * let the state of idle sibling percolate up as IDLE, instead of | |
d15bcfdb | 2902 | * portraying it as CPU_NOT_IDLE. |
89c4710e SS |
2903 | */ |
2904 | if (sd->flags & SD_SHARE_CPUPOWER && | |
2905 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) | |
5969fe06 | 2906 | sd_idle = 1; |
1da177e4 | 2907 | |
2d72376b | 2908 | schedstat_inc(sd, lb_count[CPU_NEWLY_IDLE]); |
0a2966b4 | 2909 | redo: |
d15bcfdb | 2910 | group = find_busiest_group(sd, this_cpu, &imbalance, CPU_NEWLY_IDLE, |
783609c6 | 2911 | &sd_idle, &cpus, NULL); |
1da177e4 | 2912 | if (!group) { |
d15bcfdb | 2913 | schedstat_inc(sd, lb_nobusyg[CPU_NEWLY_IDLE]); |
16cfb1c0 | 2914 | goto out_balanced; |
1da177e4 LT |
2915 | } |
2916 | ||
d15bcfdb | 2917 | busiest = find_busiest_queue(group, CPU_NEWLY_IDLE, imbalance, |
0a2966b4 | 2918 | &cpus); |
db935dbd | 2919 | if (!busiest) { |
d15bcfdb | 2920 | schedstat_inc(sd, lb_nobusyq[CPU_NEWLY_IDLE]); |
16cfb1c0 | 2921 | goto out_balanced; |
1da177e4 LT |
2922 | } |
2923 | ||
db935dbd NP |
2924 | BUG_ON(busiest == this_rq); |
2925 | ||
d15bcfdb | 2926 | schedstat_add(sd, lb_imbalance[CPU_NEWLY_IDLE], imbalance); |
d6d5cfaf | 2927 | |
43010659 | 2928 | ld_moved = 0; |
d6d5cfaf NP |
2929 | if (busiest->nr_running > 1) { |
2930 | /* Attempt to move tasks */ | |
2931 | double_lock_balance(this_rq, busiest); | |
6e82a3be IM |
2932 | /* this_rq->clock is already updated */ |
2933 | update_rq_clock(busiest); | |
43010659 | 2934 | ld_moved = move_tasks(this_rq, this_cpu, busiest, |
969bb4e4 SS |
2935 | imbalance, sd, CPU_NEWLY_IDLE, |
2936 | &all_pinned); | |
d6d5cfaf | 2937 | spin_unlock(&busiest->lock); |
0a2966b4 | 2938 | |
969bb4e4 | 2939 | if (unlikely(all_pinned)) { |
0a2966b4 CL |
2940 | cpu_clear(cpu_of(busiest), cpus); |
2941 | if (!cpus_empty(cpus)) | |
2942 | goto redo; | |
2943 | } | |
d6d5cfaf NP |
2944 | } |
2945 | ||
43010659 | 2946 | if (!ld_moved) { |
d15bcfdb | 2947 | schedstat_inc(sd, lb_failed[CPU_NEWLY_IDLE]); |
89c4710e SS |
2948 | if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && |
2949 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) | |
5969fe06 NP |
2950 | return -1; |
2951 | } else | |
16cfb1c0 | 2952 | sd->nr_balance_failed = 0; |
1da177e4 | 2953 | |
43010659 | 2954 | return ld_moved; |
16cfb1c0 NP |
2955 | |
2956 | out_balanced: | |
d15bcfdb | 2957 | schedstat_inc(sd, lb_balanced[CPU_NEWLY_IDLE]); |
48f24c4d | 2958 | if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && |
89c4710e | 2959 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
5969fe06 | 2960 | return -1; |
16cfb1c0 | 2961 | sd->nr_balance_failed = 0; |
48f24c4d | 2962 | |
16cfb1c0 | 2963 | return 0; |
1da177e4 LT |
2964 | } |
2965 | ||
2966 | /* | |
2967 | * idle_balance is called by schedule() if this_cpu is about to become | |
2968 | * idle. Attempts to pull tasks from other CPUs. | |
2969 | */ | |
70b97a7f | 2970 | static void idle_balance(int this_cpu, struct rq *this_rq) |
1da177e4 LT |
2971 | { |
2972 | struct sched_domain *sd; | |
dd41f596 IM |
2973 | int pulled_task = -1; |
2974 | unsigned long next_balance = jiffies + HZ; | |
1da177e4 LT |
2975 | |
2976 | for_each_domain(this_cpu, sd) { | |
92c4ca5c CL |
2977 | unsigned long interval; |
2978 | ||
2979 | if (!(sd->flags & SD_LOAD_BALANCE)) | |
2980 | continue; | |
2981 | ||
2982 | if (sd->flags & SD_BALANCE_NEWIDLE) | |
48f24c4d | 2983 | /* If we've pulled tasks over stop searching: */ |
1bd77f2d | 2984 | pulled_task = load_balance_newidle(this_cpu, |
92c4ca5c CL |
2985 | this_rq, sd); |
2986 | ||
2987 | interval = msecs_to_jiffies(sd->balance_interval); | |
2988 | if (time_after(next_balance, sd->last_balance + interval)) | |
2989 | next_balance = sd->last_balance + interval; | |
2990 | if (pulled_task) | |
2991 | break; | |
1da177e4 | 2992 | } |
dd41f596 | 2993 | if (pulled_task || time_after(jiffies, this_rq->next_balance)) { |
1bd77f2d CL |
2994 | /* |
2995 | * We are going idle. next_balance may be set based on | |
2996 | * a busy processor. So reset next_balance. | |
2997 | */ | |
2998 | this_rq->next_balance = next_balance; | |
dd41f596 | 2999 | } |
1da177e4 LT |
3000 | } |
3001 | ||
3002 | /* | |
3003 | * active_load_balance is run by migration threads. It pushes running tasks | |
3004 | * off the busiest CPU onto idle CPUs. It requires at least 1 task to be | |
3005 | * running on each physical CPU where possible, and avoids physical / | |
3006 | * logical imbalances. | |
3007 | * | |
3008 | * Called with busiest_rq locked. | |
3009 | */ | |
70b97a7f | 3010 | static void active_load_balance(struct rq *busiest_rq, int busiest_cpu) |
1da177e4 | 3011 | { |
39507451 | 3012 | int target_cpu = busiest_rq->push_cpu; |
70b97a7f IM |
3013 | struct sched_domain *sd; |
3014 | struct rq *target_rq; | |
39507451 | 3015 | |
48f24c4d | 3016 | /* Is there any task to move? */ |
39507451 | 3017 | if (busiest_rq->nr_running <= 1) |
39507451 NP |
3018 | return; |
3019 | ||
3020 | target_rq = cpu_rq(target_cpu); | |
1da177e4 LT |
3021 | |
3022 | /* | |
39507451 | 3023 | * This condition is "impossible", if it occurs |
41a2d6cf | 3024 | * we need to fix it. Originally reported by |
39507451 | 3025 | * Bjorn Helgaas on a 128-cpu setup. |
1da177e4 | 3026 | */ |
39507451 | 3027 | BUG_ON(busiest_rq == target_rq); |
1da177e4 | 3028 | |
39507451 NP |
3029 | /* move a task from busiest_rq to target_rq */ |
3030 | double_lock_balance(busiest_rq, target_rq); | |
6e82a3be IM |
3031 | update_rq_clock(busiest_rq); |
3032 | update_rq_clock(target_rq); | |
39507451 NP |
3033 | |
3034 | /* Search for an sd spanning us and the target CPU. */ | |
c96d145e | 3035 | for_each_domain(target_cpu, sd) { |
39507451 | 3036 | if ((sd->flags & SD_LOAD_BALANCE) && |
48f24c4d | 3037 | cpu_isset(busiest_cpu, sd->span)) |
39507451 | 3038 | break; |
c96d145e | 3039 | } |
39507451 | 3040 | |
48f24c4d | 3041 | if (likely(sd)) { |
2d72376b | 3042 | schedstat_inc(sd, alb_count); |
39507451 | 3043 | |
43010659 PW |
3044 | if (move_one_task(target_rq, target_cpu, busiest_rq, |
3045 | sd, CPU_IDLE)) | |
48f24c4d IM |
3046 | schedstat_inc(sd, alb_pushed); |
3047 | else | |
3048 | schedstat_inc(sd, alb_failed); | |
3049 | } | |
39507451 | 3050 | spin_unlock(&target_rq->lock); |
1da177e4 LT |
3051 | } |
3052 | ||
46cb4b7c SS |
3053 | #ifdef CONFIG_NO_HZ |
3054 | static struct { | |
3055 | atomic_t load_balancer; | |
41a2d6cf | 3056 | cpumask_t cpu_mask; |
46cb4b7c SS |
3057 | } nohz ____cacheline_aligned = { |
3058 | .load_balancer = ATOMIC_INIT(-1), | |
3059 | .cpu_mask = CPU_MASK_NONE, | |
3060 | }; | |
3061 | ||
7835b98b | 3062 | /* |
46cb4b7c SS |
3063 | * This routine will try to nominate the ilb (idle load balancing) |
3064 | * owner among the cpus whose ticks are stopped. ilb owner will do the idle | |
3065 | * load balancing on behalf of all those cpus. If all the cpus in the system | |
3066 | * go into this tickless mode, then there will be no ilb owner (as there is | |
3067 | * no need for one) and all the cpus will sleep till the next wakeup event | |
3068 | * arrives... | |
3069 | * | |
3070 | * For the ilb owner, tick is not stopped. And this tick will be used | |
3071 | * for idle load balancing. ilb owner will still be part of | |
3072 | * nohz.cpu_mask.. | |
7835b98b | 3073 | * |
46cb4b7c SS |
3074 | * While stopping the tick, this cpu will become the ilb owner if there |
3075 | * is no other owner. And will be the owner till that cpu becomes busy | |
3076 | * or if all cpus in the system stop their ticks at which point | |
3077 | * there is no need for ilb owner. | |
3078 | * | |
3079 | * When the ilb owner becomes busy, it nominates another owner, during the | |
3080 | * next busy scheduler_tick() | |
3081 | */ | |
3082 | int select_nohz_load_balancer(int stop_tick) | |
3083 | { | |
3084 | int cpu = smp_processor_id(); | |
3085 | ||
3086 | if (stop_tick) { | |
3087 | cpu_set(cpu, nohz.cpu_mask); | |
3088 | cpu_rq(cpu)->in_nohz_recently = 1; | |
3089 | ||
3090 | /* | |
3091 | * If we are going offline and still the leader, give up! | |
3092 | */ | |
3093 | if (cpu_is_offline(cpu) && | |
3094 | atomic_read(&nohz.load_balancer) == cpu) { | |
3095 | if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu) | |
3096 | BUG(); | |
3097 | return 0; | |
3098 | } | |
3099 | ||
3100 | /* time for ilb owner also to sleep */ | |
3101 | if (cpus_weight(nohz.cpu_mask) == num_online_cpus()) { | |
3102 | if (atomic_read(&nohz.load_balancer) == cpu) | |
3103 | atomic_set(&nohz.load_balancer, -1); | |
3104 | return 0; | |
3105 | } | |
3106 | ||
3107 | if (atomic_read(&nohz.load_balancer) == -1) { | |
3108 | /* make me the ilb owner */ | |
3109 | if (atomic_cmpxchg(&nohz.load_balancer, -1, cpu) == -1) | |
3110 | return 1; | |
3111 | } else if (atomic_read(&nohz.load_balancer) == cpu) | |
3112 | return 1; | |
3113 | } else { | |
3114 | if (!cpu_isset(cpu, nohz.cpu_mask)) | |
3115 | return 0; | |
3116 | ||
3117 | cpu_clear(cpu, nohz.cpu_mask); | |
3118 | ||
3119 | if (atomic_read(&nohz.load_balancer) == cpu) | |
3120 | if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu) | |
3121 | BUG(); | |
3122 | } | |
3123 | return 0; | |
3124 | } | |
3125 | #endif | |
3126 | ||
3127 | static DEFINE_SPINLOCK(balancing); | |
3128 | ||
3129 | /* | |
7835b98b CL |
3130 | * It checks each scheduling domain to see if it is due to be balanced, |
3131 | * and initiates a balancing operation if so. | |
3132 | * | |
3133 | * Balancing parameters are set up in arch_init_sched_domains. | |
3134 | */ | |
a9957449 | 3135 | static void rebalance_domains(int cpu, enum cpu_idle_type idle) |
7835b98b | 3136 | { |
46cb4b7c SS |
3137 | int balance = 1; |
3138 | struct rq *rq = cpu_rq(cpu); | |
7835b98b CL |
3139 | unsigned long interval; |
3140 | struct sched_domain *sd; | |
46cb4b7c | 3141 | /* Earliest time when we have to do rebalance again */ |
c9819f45 | 3142 | unsigned long next_balance = jiffies + 60*HZ; |
f549da84 | 3143 | int update_next_balance = 0; |
1da177e4 | 3144 | |
46cb4b7c | 3145 | for_each_domain(cpu, sd) { |
1da177e4 LT |
3146 | if (!(sd->flags & SD_LOAD_BALANCE)) |
3147 | continue; | |
3148 | ||
3149 | interval = sd->balance_interval; | |
d15bcfdb | 3150 | if (idle != CPU_IDLE) |
1da177e4 LT |
3151 | interval *= sd->busy_factor; |
3152 | ||
3153 | /* scale ms to jiffies */ | |
3154 | interval = msecs_to_jiffies(interval); | |
3155 | if (unlikely(!interval)) | |
3156 | interval = 1; | |
dd41f596 IM |
3157 | if (interval > HZ*NR_CPUS/10) |
3158 | interval = HZ*NR_CPUS/10; | |
3159 | ||
1da177e4 | 3160 | |
08c183f3 CL |
3161 | if (sd->flags & SD_SERIALIZE) { |
3162 | if (!spin_trylock(&balancing)) | |
3163 | goto out; | |
3164 | } | |
3165 | ||
c9819f45 | 3166 | if (time_after_eq(jiffies, sd->last_balance + interval)) { |
46cb4b7c | 3167 | if (load_balance(cpu, rq, sd, idle, &balance)) { |
fa3b6ddc SS |
3168 | /* |
3169 | * We've pulled tasks over so either we're no | |
5969fe06 NP |
3170 | * longer idle, or one of our SMT siblings is |
3171 | * not idle. | |
3172 | */ | |
d15bcfdb | 3173 | idle = CPU_NOT_IDLE; |
1da177e4 | 3174 | } |
1bd77f2d | 3175 | sd->last_balance = jiffies; |
1da177e4 | 3176 | } |
08c183f3 CL |
3177 | if (sd->flags & SD_SERIALIZE) |
3178 | spin_unlock(&balancing); | |
3179 | out: | |
f549da84 | 3180 | if (time_after(next_balance, sd->last_balance + interval)) { |
c9819f45 | 3181 | next_balance = sd->last_balance + interval; |
f549da84 SS |
3182 | update_next_balance = 1; |
3183 | } | |
783609c6 SS |
3184 | |
3185 | /* | |
3186 | * Stop the load balance at this level. There is another | |
3187 | * CPU in our sched group which is doing load balancing more | |
3188 | * actively. | |
3189 | */ | |
3190 | if (!balance) | |
3191 | break; | |
1da177e4 | 3192 | } |
f549da84 SS |
3193 | |
3194 | /* | |
3195 | * next_balance will be updated only when there is a need. | |
3196 | * When the cpu is attached to null domain for ex, it will not be | |
3197 | * updated. | |
3198 | */ | |
3199 | if (likely(update_next_balance)) | |
3200 | rq->next_balance = next_balance; | |
46cb4b7c SS |
3201 | } |
3202 | ||
3203 | /* | |
3204 | * run_rebalance_domains is triggered when needed from the scheduler tick. | |
3205 | * In CONFIG_NO_HZ case, the idle load balance owner will do the | |
3206 | * rebalancing for all the cpus for whom scheduler ticks are stopped. | |
3207 | */ | |
3208 | static void run_rebalance_domains(struct softirq_action *h) | |
3209 | { | |
dd41f596 IM |
3210 | int this_cpu = smp_processor_id(); |
3211 | struct rq *this_rq = cpu_rq(this_cpu); | |
3212 | enum cpu_idle_type idle = this_rq->idle_at_tick ? | |
3213 | CPU_IDLE : CPU_NOT_IDLE; | |
46cb4b7c | 3214 | |
dd41f596 | 3215 | rebalance_domains(this_cpu, idle); |
46cb4b7c SS |
3216 | |
3217 | #ifdef CONFIG_NO_HZ | |
3218 | /* | |
3219 | * If this cpu is the owner for idle load balancing, then do the | |
3220 | * balancing on behalf of the other idle cpus whose ticks are | |
3221 | * stopped. | |
3222 | */ | |
dd41f596 IM |
3223 | if (this_rq->idle_at_tick && |
3224 | atomic_read(&nohz.load_balancer) == this_cpu) { | |
46cb4b7c SS |
3225 | cpumask_t cpus = nohz.cpu_mask; |
3226 | struct rq *rq; | |
3227 | int balance_cpu; | |
3228 | ||
dd41f596 | 3229 | cpu_clear(this_cpu, cpus); |
46cb4b7c SS |
3230 | for_each_cpu_mask(balance_cpu, cpus) { |
3231 | /* | |
3232 | * If this cpu gets work to do, stop the load balancing | |
3233 | * work being done for other cpus. Next load | |
3234 | * balancing owner will pick it up. | |
3235 | */ | |
3236 | if (need_resched()) | |
3237 | break; | |
3238 | ||
de0cf899 | 3239 | rebalance_domains(balance_cpu, CPU_IDLE); |
46cb4b7c SS |
3240 | |
3241 | rq = cpu_rq(balance_cpu); | |
dd41f596 IM |
3242 | if (time_after(this_rq->next_balance, rq->next_balance)) |
3243 | this_rq->next_balance = rq->next_balance; | |
46cb4b7c SS |
3244 | } |
3245 | } | |
3246 | #endif | |
3247 | } | |
3248 | ||
3249 | /* | |
3250 | * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing. | |
3251 | * | |
3252 | * In case of CONFIG_NO_HZ, this is the place where we nominate a new | |
3253 | * idle load balancing owner or decide to stop the periodic load balancing, | |
3254 | * if the whole system is idle. | |
3255 | */ | |
dd41f596 | 3256 | static inline void trigger_load_balance(struct rq *rq, int cpu) |
46cb4b7c | 3257 | { |
46cb4b7c SS |
3258 | #ifdef CONFIG_NO_HZ |
3259 | /* | |
3260 | * If we were in the nohz mode recently and busy at the current | |
3261 | * scheduler tick, then check if we need to nominate new idle | |
3262 | * load balancer. | |
3263 | */ | |
3264 | if (rq->in_nohz_recently && !rq->idle_at_tick) { | |
3265 | rq->in_nohz_recently = 0; | |
3266 | ||
3267 | if (atomic_read(&nohz.load_balancer) == cpu) { | |
3268 | cpu_clear(cpu, nohz.cpu_mask); | |
3269 | atomic_set(&nohz.load_balancer, -1); | |
3270 | } | |
3271 | ||
3272 | if (atomic_read(&nohz.load_balancer) == -1) { | |
3273 | /* | |
3274 | * simple selection for now: Nominate the | |
3275 | * first cpu in the nohz list to be the next | |
3276 | * ilb owner. | |
3277 | * | |
3278 | * TBD: Traverse the sched domains and nominate | |
3279 | * the nearest cpu in the nohz.cpu_mask. | |
3280 | */ | |
3281 | int ilb = first_cpu(nohz.cpu_mask); | |
3282 | ||
3283 | if (ilb != NR_CPUS) | |
3284 | resched_cpu(ilb); | |
3285 | } | |
3286 | } | |
3287 | ||
3288 | /* | |
3289 | * If this cpu is idle and doing idle load balancing for all the | |
3290 | * cpus with ticks stopped, is it time for that to stop? | |
3291 | */ | |
3292 | if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) == cpu && | |
3293 | cpus_weight(nohz.cpu_mask) == num_online_cpus()) { | |
3294 | resched_cpu(cpu); | |
3295 | return; | |
3296 | } | |
3297 | ||
3298 | /* | |
3299 | * If this cpu is idle and the idle load balancing is done by | |
3300 | * someone else, then no need raise the SCHED_SOFTIRQ | |
3301 | */ | |
3302 | if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) != cpu && | |
3303 | cpu_isset(cpu, nohz.cpu_mask)) | |
3304 | return; | |
3305 | #endif | |
3306 | if (time_after_eq(jiffies, rq->next_balance)) | |
3307 | raise_softirq(SCHED_SOFTIRQ); | |
1da177e4 | 3308 | } |
dd41f596 IM |
3309 | |
3310 | #else /* CONFIG_SMP */ | |
3311 | ||
1da177e4 LT |
3312 | /* |
3313 | * on UP we do not need to balance between CPUs: | |
3314 | */ | |
70b97a7f | 3315 | static inline void idle_balance(int cpu, struct rq *rq) |
1da177e4 LT |
3316 | { |
3317 | } | |
dd41f596 | 3318 | |
1da177e4 LT |
3319 | #endif |
3320 | ||
1da177e4 LT |
3321 | DEFINE_PER_CPU(struct kernel_stat, kstat); |
3322 | ||
3323 | EXPORT_PER_CPU_SYMBOL(kstat); | |
3324 | ||
3325 | /* | |
41b86e9c IM |
3326 | * Return p->sum_exec_runtime plus any more ns on the sched_clock |
3327 | * that have not yet been banked in case the task is currently running. | |
1da177e4 | 3328 | */ |
41b86e9c | 3329 | unsigned long long task_sched_runtime(struct task_struct *p) |
1da177e4 | 3330 | { |
1da177e4 | 3331 | unsigned long flags; |
41b86e9c IM |
3332 | u64 ns, delta_exec; |
3333 | struct rq *rq; | |
48f24c4d | 3334 | |
41b86e9c IM |
3335 | rq = task_rq_lock(p, &flags); |
3336 | ns = p->se.sum_exec_runtime; | |
3337 | if (rq->curr == p) { | |
a8e504d2 IM |
3338 | update_rq_clock(rq); |
3339 | delta_exec = rq->clock - p->se.exec_start; | |
41b86e9c IM |
3340 | if ((s64)delta_exec > 0) |
3341 | ns += delta_exec; | |
3342 | } | |
3343 | task_rq_unlock(rq, &flags); | |
48f24c4d | 3344 | |
1da177e4 LT |
3345 | return ns; |
3346 | } | |
3347 | ||
1da177e4 LT |
3348 | /* |
3349 | * Account user cpu time to a process. | |
3350 | * @p: the process that the cpu time gets accounted to | |
1da177e4 LT |
3351 | * @cputime: the cpu time spent in user space since the last update |
3352 | */ | |
3353 | void account_user_time(struct task_struct *p, cputime_t cputime) | |
3354 | { | |
3355 | struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; | |
3356 | cputime64_t tmp; | |
3357 | ||
3358 | p->utime = cputime_add(p->utime, cputime); | |
3359 | ||
3360 | /* Add user time to cpustat. */ | |
3361 | tmp = cputime_to_cputime64(cputime); | |
3362 | if (TASK_NICE(p) > 0) | |
3363 | cpustat->nice = cputime64_add(cpustat->nice, tmp); | |
3364 | else | |
3365 | cpustat->user = cputime64_add(cpustat->user, tmp); | |
3366 | } | |
3367 | ||
94886b84 LV |
3368 | /* |
3369 | * Account guest cpu time to a process. | |
3370 | * @p: the process that the cpu time gets accounted to | |
3371 | * @cputime: the cpu time spent in virtual machine since the last update | |
3372 | */ | |
f7402e03 | 3373 | static void account_guest_time(struct task_struct *p, cputime_t cputime) |
94886b84 LV |
3374 | { |
3375 | cputime64_t tmp; | |
3376 | struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; | |
3377 | ||
3378 | tmp = cputime_to_cputime64(cputime); | |
3379 | ||
3380 | p->utime = cputime_add(p->utime, cputime); | |
3381 | p->gtime = cputime_add(p->gtime, cputime); | |
3382 | ||
3383 | cpustat->user = cputime64_add(cpustat->user, tmp); | |
3384 | cpustat->guest = cputime64_add(cpustat->guest, tmp); | |
3385 | } | |
3386 | ||
c66f08be MN |
3387 | /* |
3388 | * Account scaled user cpu time to a process. | |
3389 | * @p: the process that the cpu time gets accounted to | |
3390 | * @cputime: the cpu time spent in user space since the last update | |
3391 | */ | |
3392 | void account_user_time_scaled(struct task_struct *p, cputime_t cputime) | |
3393 | { | |
3394 | p->utimescaled = cputime_add(p->utimescaled, cputime); | |
3395 | } | |
3396 | ||
1da177e4 LT |
3397 | /* |
3398 | * Account system cpu time to a process. | |
3399 | * @p: the process that the cpu time gets accounted to | |
3400 | * @hardirq_offset: the offset to subtract from hardirq_count() | |
3401 | * @cputime: the cpu time spent in kernel space since the last update | |
3402 | */ | |
3403 | void account_system_time(struct task_struct *p, int hardirq_offset, | |
3404 | cputime_t cputime) | |
3405 | { | |
3406 | struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; | |
70b97a7f | 3407 | struct rq *rq = this_rq(); |
1da177e4 LT |
3408 | cputime64_t tmp; |
3409 | ||
9778385d CB |
3410 | if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) |
3411 | return account_guest_time(p, cputime); | |
94886b84 | 3412 | |
1da177e4 LT |
3413 | p->stime = cputime_add(p->stime, cputime); |
3414 | ||
3415 | /* Add system time to cpustat. */ | |
3416 | tmp = cputime_to_cputime64(cputime); | |
3417 | if (hardirq_count() - hardirq_offset) | |
3418 | cpustat->irq = cputime64_add(cpustat->irq, tmp); | |
3419 | else if (softirq_count()) | |
3420 | cpustat->softirq = cputime64_add(cpustat->softirq, tmp); | |
cfb52856 | 3421 | else if (p != rq->idle) |
1da177e4 | 3422 | cpustat->system = cputime64_add(cpustat->system, tmp); |
cfb52856 | 3423 | else if (atomic_read(&rq->nr_iowait) > 0) |
1da177e4 LT |
3424 | cpustat->iowait = cputime64_add(cpustat->iowait, tmp); |
3425 | else | |
3426 | cpustat->idle = cputime64_add(cpustat->idle, tmp); | |
3427 | /* Account for system time used */ | |
3428 | acct_update_integrals(p); | |
1da177e4 LT |
3429 | } |
3430 | ||
c66f08be MN |
3431 | /* |
3432 | * Account scaled system cpu time to a process. | |
3433 | * @p: the process that the cpu time gets accounted to | |
3434 | * @hardirq_offset: the offset to subtract from hardirq_count() | |
3435 | * @cputime: the cpu time spent in kernel space since the last update | |
3436 | */ | |
3437 | void account_system_time_scaled(struct task_struct *p, cputime_t cputime) | |
3438 | { | |
3439 | p->stimescaled = cputime_add(p->stimescaled, cputime); | |
3440 | } | |
3441 | ||
1da177e4 LT |
3442 | /* |
3443 | * Account for involuntary wait time. | |
3444 | * @p: the process from which the cpu time has been stolen | |
3445 | * @steal: the cpu time spent in involuntary wait | |
3446 | */ | |
3447 | void account_steal_time(struct task_struct *p, cputime_t steal) | |
3448 | { | |
3449 | struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; | |
3450 | cputime64_t tmp = cputime_to_cputime64(steal); | |
70b97a7f | 3451 | struct rq *rq = this_rq(); |
1da177e4 LT |
3452 | |
3453 | if (p == rq->idle) { | |
3454 | p->stime = cputime_add(p->stime, steal); | |
3455 | if (atomic_read(&rq->nr_iowait) > 0) | |
3456 | cpustat->iowait = cputime64_add(cpustat->iowait, tmp); | |
3457 | else | |
3458 | cpustat->idle = cputime64_add(cpustat->idle, tmp); | |
cfb52856 | 3459 | } else |
1da177e4 LT |
3460 | cpustat->steal = cputime64_add(cpustat->steal, tmp); |
3461 | } | |
3462 | ||
7835b98b CL |
3463 | /* |
3464 | * This function gets called by the timer code, with HZ frequency. | |
3465 | * We call it with interrupts disabled. | |
3466 | * | |
3467 | * It also gets called by the fork code, when changing the parent's | |
3468 | * timeslices. | |
3469 | */ | |
3470 | void scheduler_tick(void) | |
3471 | { | |
7835b98b CL |
3472 | int cpu = smp_processor_id(); |
3473 | struct rq *rq = cpu_rq(cpu); | |
dd41f596 | 3474 | struct task_struct *curr = rq->curr; |
529c7726 | 3475 | u64 next_tick = rq->tick_timestamp + TICK_NSEC; |
dd41f596 IM |
3476 | |
3477 | spin_lock(&rq->lock); | |
546fe3c9 | 3478 | __update_rq_clock(rq); |
529c7726 IM |
3479 | /* |
3480 | * Let rq->clock advance by at least TICK_NSEC: | |
3481 | */ | |
3482 | if (unlikely(rq->clock < next_tick)) | |
3483 | rq->clock = next_tick; | |
3484 | rq->tick_timestamp = rq->clock; | |
f1a438d8 | 3485 | update_cpu_load(rq); |
dd41f596 IM |
3486 | if (curr != rq->idle) /* FIXME: needed? */ |
3487 | curr->sched_class->task_tick(rq, curr); | |
dd41f596 | 3488 | spin_unlock(&rq->lock); |
7835b98b | 3489 | |
e418e1c2 | 3490 | #ifdef CONFIG_SMP |
dd41f596 IM |
3491 | rq->idle_at_tick = idle_cpu(cpu); |
3492 | trigger_load_balance(rq, cpu); | |
e418e1c2 | 3493 | #endif |
1da177e4 LT |
3494 | } |
3495 | ||
1da177e4 LT |
3496 | #if defined(CONFIG_PREEMPT) && defined(CONFIG_DEBUG_PREEMPT) |
3497 | ||
3498 | void fastcall add_preempt_count(int val) | |
3499 | { | |
3500 | /* | |
3501 | * Underflow? | |
3502 | */ | |
9a11b49a IM |
3503 | if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0))) |
3504 | return; | |
1da177e4 LT |
3505 | preempt_count() += val; |
3506 | /* | |
3507 | * Spinlock count overflowing soon? | |
3508 | */ | |
33859f7f MOS |
3509 | DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >= |
3510 | PREEMPT_MASK - 10); | |
1da177e4 LT |
3511 | } |
3512 | EXPORT_SYMBOL(add_preempt_count); | |
3513 | ||
3514 | void fastcall sub_preempt_count(int val) | |
3515 | { | |
3516 | /* | |
3517 | * Underflow? | |
3518 | */ | |
9a11b49a IM |
3519 | if (DEBUG_LOCKS_WARN_ON(val > preempt_count())) |
3520 | return; | |
1da177e4 LT |
3521 | /* |
3522 | * Is the spinlock portion underflowing? | |
3523 | */ | |
9a11b49a IM |
3524 | if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) && |
3525 | !(preempt_count() & PREEMPT_MASK))) | |
3526 | return; | |
3527 | ||
1da177e4 LT |
3528 | preempt_count() -= val; |
3529 | } | |
3530 | EXPORT_SYMBOL(sub_preempt_count); | |
3531 | ||
3532 | #endif | |
3533 | ||
3534 | /* | |
dd41f596 | 3535 | * Print scheduling while atomic bug: |
1da177e4 | 3536 | */ |
dd41f596 | 3537 | static noinline void __schedule_bug(struct task_struct *prev) |
1da177e4 | 3538 | { |
838225b4 SS |
3539 | struct pt_regs *regs = get_irq_regs(); |
3540 | ||
3541 | printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n", | |
3542 | prev->comm, prev->pid, preempt_count()); | |
3543 | ||
dd41f596 IM |
3544 | debug_show_held_locks(prev); |
3545 | if (irqs_disabled()) | |
3546 | print_irqtrace_events(prev); | |
838225b4 SS |
3547 | |
3548 | if (regs) | |
3549 | show_regs(regs); | |
3550 | else | |
3551 | dump_stack(); | |
dd41f596 | 3552 | } |
1da177e4 | 3553 | |
dd41f596 IM |
3554 | /* |
3555 | * Various schedule()-time debugging checks and statistics: | |
3556 | */ | |
3557 | static inline void schedule_debug(struct task_struct *prev) | |
3558 | { | |
1da177e4 | 3559 | /* |
41a2d6cf | 3560 | * Test if we are atomic. Since do_exit() needs to call into |
1da177e4 LT |
3561 | * schedule() atomically, we ignore that path for now. |
3562 | * Otherwise, whine if we are scheduling when we should not be. | |
3563 | */ | |
dd41f596 IM |
3564 | if (unlikely(in_atomic_preempt_off()) && unlikely(!prev->exit_state)) |
3565 | __schedule_bug(prev); | |
3566 | ||
1da177e4 LT |
3567 | profile_hit(SCHED_PROFILING, __builtin_return_address(0)); |
3568 | ||
2d72376b | 3569 | schedstat_inc(this_rq(), sched_count); |
b8efb561 IM |
3570 | #ifdef CONFIG_SCHEDSTATS |
3571 | if (unlikely(prev->lock_depth >= 0)) { | |
2d72376b IM |
3572 | schedstat_inc(this_rq(), bkl_count); |
3573 | schedstat_inc(prev, sched_info.bkl_count); | |
b8efb561 IM |
3574 | } |
3575 | #endif | |
dd41f596 IM |
3576 | } |
3577 | ||
3578 | /* | |
3579 | * Pick up the highest-prio task: | |
3580 | */ | |
3581 | static inline struct task_struct * | |
ff95f3df | 3582 | pick_next_task(struct rq *rq, struct task_struct *prev) |
dd41f596 | 3583 | { |
5522d5d5 | 3584 | const struct sched_class *class; |
dd41f596 | 3585 | struct task_struct *p; |
1da177e4 LT |
3586 | |
3587 | /* | |
dd41f596 IM |
3588 | * Optimization: we know that if all tasks are in |
3589 | * the fair class we can call that function directly: | |
1da177e4 | 3590 | */ |
dd41f596 | 3591 | if (likely(rq->nr_running == rq->cfs.nr_running)) { |
fb8d4724 | 3592 | p = fair_sched_class.pick_next_task(rq); |
dd41f596 IM |
3593 | if (likely(p)) |
3594 | return p; | |
1da177e4 LT |
3595 | } |
3596 | ||
dd41f596 IM |
3597 | class = sched_class_highest; |
3598 | for ( ; ; ) { | |
fb8d4724 | 3599 | p = class->pick_next_task(rq); |
dd41f596 IM |
3600 | if (p) |
3601 | return p; | |
3602 | /* | |
3603 | * Will never be NULL as the idle class always | |
3604 | * returns a non-NULL p: | |
3605 | */ | |
3606 | class = class->next; | |
3607 | } | |
3608 | } | |
1da177e4 | 3609 | |
dd41f596 IM |
3610 | /* |
3611 | * schedule() is the main scheduler function. | |
3612 | */ | |
3613 | asmlinkage void __sched schedule(void) | |
3614 | { | |
3615 | struct task_struct *prev, *next; | |
3616 | long *switch_count; | |
3617 | struct rq *rq; | |
dd41f596 IM |
3618 | int cpu; |
3619 | ||
3620 | need_resched: | |
3621 | preempt_disable(); | |
3622 | cpu = smp_processor_id(); | |
3623 | rq = cpu_rq(cpu); | |
3624 | rcu_qsctr_inc(cpu); | |
3625 | prev = rq->curr; | |
3626 | switch_count = &prev->nivcsw; | |
3627 | ||
3628 | release_kernel_lock(prev); | |
3629 | need_resched_nonpreemptible: | |
3630 | ||
3631 | schedule_debug(prev); | |
1da177e4 | 3632 | |
1e819950 IM |
3633 | /* |
3634 | * Do the rq-clock update outside the rq lock: | |
3635 | */ | |
3636 | local_irq_disable(); | |
c1b3da3e | 3637 | __update_rq_clock(rq); |
1e819950 IM |
3638 | spin_lock(&rq->lock); |
3639 | clear_tsk_need_resched(prev); | |
1da177e4 | 3640 | |
1da177e4 | 3641 | if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) { |
1da177e4 | 3642 | if (unlikely((prev->state & TASK_INTERRUPTIBLE) && |
dd41f596 | 3643 | unlikely(signal_pending(prev)))) { |
1da177e4 | 3644 | prev->state = TASK_RUNNING; |
dd41f596 | 3645 | } else { |
2e1cb74a | 3646 | deactivate_task(rq, prev, 1); |
1da177e4 | 3647 | } |
dd41f596 | 3648 | switch_count = &prev->nvcsw; |
1da177e4 LT |
3649 | } |
3650 | ||
dd41f596 | 3651 | if (unlikely(!rq->nr_running)) |
1da177e4 | 3652 | idle_balance(cpu, rq); |
1da177e4 | 3653 | |
31ee529c | 3654 | prev->sched_class->put_prev_task(rq, prev); |
ff95f3df | 3655 | next = pick_next_task(rq, prev); |
1da177e4 LT |
3656 | |
3657 | sched_info_switch(prev, next); | |
dd41f596 | 3658 | |
1da177e4 | 3659 | if (likely(prev != next)) { |
1da177e4 LT |
3660 | rq->nr_switches++; |
3661 | rq->curr = next; | |
3662 | ++*switch_count; | |
3663 | ||
dd41f596 | 3664 | context_switch(rq, prev, next); /* unlocks the rq */ |
1da177e4 LT |
3665 | } else |
3666 | spin_unlock_irq(&rq->lock); | |
3667 | ||
dd41f596 IM |
3668 | if (unlikely(reacquire_kernel_lock(current) < 0)) { |
3669 | cpu = smp_processor_id(); | |
3670 | rq = cpu_rq(cpu); | |
1da177e4 | 3671 | goto need_resched_nonpreemptible; |
dd41f596 | 3672 | } |
1da177e4 LT |
3673 | preempt_enable_no_resched(); |
3674 | if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) | |
3675 | goto need_resched; | |
3676 | } | |
1da177e4 LT |
3677 | EXPORT_SYMBOL(schedule); |
3678 | ||
3679 | #ifdef CONFIG_PREEMPT | |
3680 | /* | |
2ed6e34f | 3681 | * this is the entry point to schedule() from in-kernel preemption |
41a2d6cf | 3682 | * off of preempt_enable. Kernel preemptions off return from interrupt |
1da177e4 LT |
3683 | * occur there and call schedule directly. |
3684 | */ | |
3685 | asmlinkage void __sched preempt_schedule(void) | |
3686 | { | |
3687 | struct thread_info *ti = current_thread_info(); | |
3688 | #ifdef CONFIG_PREEMPT_BKL | |
3689 | struct task_struct *task = current; | |
3690 | int saved_lock_depth; | |
3691 | #endif | |
3692 | /* | |
3693 | * If there is a non-zero preempt_count or interrupts are disabled, | |
41a2d6cf | 3694 | * we do not want to preempt the current task. Just return.. |
1da177e4 | 3695 | */ |
beed33a8 | 3696 | if (likely(ti->preempt_count || irqs_disabled())) |
1da177e4 LT |
3697 | return; |
3698 | ||
3a5c359a AK |
3699 | do { |
3700 | add_preempt_count(PREEMPT_ACTIVE); | |
3701 | ||
3702 | /* | |
3703 | * We keep the big kernel semaphore locked, but we | |
3704 | * clear ->lock_depth so that schedule() doesnt | |
3705 | * auto-release the semaphore: | |
3706 | */ | |
1da177e4 | 3707 | #ifdef CONFIG_PREEMPT_BKL |
3a5c359a AK |
3708 | saved_lock_depth = task->lock_depth; |
3709 | task->lock_depth = -1; | |
1da177e4 | 3710 | #endif |
3a5c359a | 3711 | schedule(); |
1da177e4 | 3712 | #ifdef CONFIG_PREEMPT_BKL |
3a5c359a | 3713 | task->lock_depth = saved_lock_depth; |
1da177e4 | 3714 | #endif |
3a5c359a | 3715 | sub_preempt_count(PREEMPT_ACTIVE); |
1da177e4 | 3716 | |
3a5c359a AK |
3717 | /* |
3718 | * Check again in case we missed a preemption opportunity | |
3719 | * between schedule and now. | |
3720 | */ | |
3721 | barrier(); | |
3722 | } while (unlikely(test_thread_flag(TIF_NEED_RESCHED))); | |
1da177e4 | 3723 | } |
1da177e4 LT |
3724 | EXPORT_SYMBOL(preempt_schedule); |
3725 | ||
3726 | /* | |
2ed6e34f | 3727 | * this is the entry point to schedule() from kernel preemption |
1da177e4 LT |
3728 | * off of irq context. |
3729 | * Note, that this is called and return with irqs disabled. This will | |
3730 | * protect us against recursive calling from irq. | |
3731 | */ | |
3732 | asmlinkage void __sched preempt_schedule_irq(void) | |
3733 | { | |
3734 | struct thread_info *ti = current_thread_info(); | |
3735 | #ifdef CONFIG_PREEMPT_BKL | |
3736 | struct task_struct *task = current; | |
3737 | int saved_lock_depth; | |
3738 | #endif | |
2ed6e34f | 3739 | /* Catch callers which need to be fixed */ |
1da177e4 LT |
3740 | BUG_ON(ti->preempt_count || !irqs_disabled()); |
3741 | ||
3a5c359a AK |
3742 | do { |
3743 | add_preempt_count(PREEMPT_ACTIVE); | |
3744 | ||
3745 | /* | |
3746 | * We keep the big kernel semaphore locked, but we | |
3747 | * clear ->lock_depth so that schedule() doesnt | |
3748 | * auto-release the semaphore: | |
3749 | */ | |
1da177e4 | 3750 | #ifdef CONFIG_PREEMPT_BKL |
3a5c359a AK |
3751 | saved_lock_depth = task->lock_depth; |
3752 | task->lock_depth = -1; | |
1da177e4 | 3753 | #endif |
3a5c359a AK |
3754 | local_irq_enable(); |
3755 | schedule(); | |
3756 | local_irq_disable(); | |
1da177e4 | 3757 | #ifdef CONFIG_PREEMPT_BKL |
3a5c359a | 3758 | task->lock_depth = saved_lock_depth; |
1da177e4 | 3759 | #endif |
3a5c359a | 3760 | sub_preempt_count(PREEMPT_ACTIVE); |
1da177e4 | 3761 | |
3a5c359a AK |
3762 | /* |
3763 | * Check again in case we missed a preemption opportunity | |
3764 | * between schedule and now. | |
3765 | */ | |
3766 | barrier(); | |
3767 | } while (unlikely(test_thread_flag(TIF_NEED_RESCHED))); | |
1da177e4 LT |
3768 | } |
3769 | ||
3770 | #endif /* CONFIG_PREEMPT */ | |
3771 | ||
95cdf3b7 IM |
3772 | int default_wake_function(wait_queue_t *curr, unsigned mode, int sync, |
3773 | void *key) | |
1da177e4 | 3774 | { |
48f24c4d | 3775 | return try_to_wake_up(curr->private, mode, sync); |
1da177e4 | 3776 | } |
1da177e4 LT |
3777 | EXPORT_SYMBOL(default_wake_function); |
3778 | ||
3779 | /* | |
41a2d6cf IM |
3780 | * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just |
3781 | * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve | |
1da177e4 LT |
3782 | * number) then we wake all the non-exclusive tasks and one exclusive task. |
3783 | * | |
3784 | * There are circumstances in which we can try to wake a task which has already | |
41a2d6cf | 3785 | * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns |
1da177e4 LT |
3786 | * zero in this (rare) case, and we handle it by continuing to scan the queue. |
3787 | */ | |
3788 | static void __wake_up_common(wait_queue_head_t *q, unsigned int mode, | |
3789 | int nr_exclusive, int sync, void *key) | |
3790 | { | |
2e45874c | 3791 | wait_queue_t *curr, *next; |
1da177e4 | 3792 | |
2e45874c | 3793 | list_for_each_entry_safe(curr, next, &q->task_list, task_list) { |
48f24c4d IM |
3794 | unsigned flags = curr->flags; |
3795 | ||
1da177e4 | 3796 | if (curr->func(curr, mode, sync, key) && |
48f24c4d | 3797 | (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive) |
1da177e4 LT |
3798 | break; |
3799 | } | |
3800 | } | |
3801 | ||
3802 | /** | |
3803 | * __wake_up - wake up threads blocked on a waitqueue. | |
3804 | * @q: the waitqueue | |
3805 | * @mode: which threads | |
3806 | * @nr_exclusive: how many wake-one or wake-many threads to wake up | |
67be2dd1 | 3807 | * @key: is directly passed to the wakeup function |
1da177e4 LT |
3808 | */ |
3809 | void fastcall __wake_up(wait_queue_head_t *q, unsigned int mode, | |
95cdf3b7 | 3810 | int nr_exclusive, void *key) |
1da177e4 LT |
3811 | { |
3812 | unsigned long flags; | |
3813 | ||
3814 | spin_lock_irqsave(&q->lock, flags); | |
3815 | __wake_up_common(q, mode, nr_exclusive, 0, key); | |
3816 | spin_unlock_irqrestore(&q->lock, flags); | |
3817 | } | |
1da177e4 LT |
3818 | EXPORT_SYMBOL(__wake_up); |
3819 | ||
3820 | /* | |
3821 | * Same as __wake_up but called with the spinlock in wait_queue_head_t held. | |
3822 | */ | |
3823 | void fastcall __wake_up_locked(wait_queue_head_t *q, unsigned int mode) | |
3824 | { | |
3825 | __wake_up_common(q, mode, 1, 0, NULL); | |
3826 | } | |
3827 | ||
3828 | /** | |
67be2dd1 | 3829 | * __wake_up_sync - wake up threads blocked on a waitqueue. |
1da177e4 LT |
3830 | * @q: the waitqueue |
3831 | * @mode: which threads | |
3832 | * @nr_exclusive: how many wake-one or wake-many threads to wake up | |
3833 | * | |
3834 | * The sync wakeup differs that the waker knows that it will schedule | |
3835 | * away soon, so while the target thread will be woken up, it will not | |
3836 | * be migrated to another CPU - ie. the two threads are 'synchronized' | |
3837 | * with each other. This can prevent needless bouncing between CPUs. | |
3838 | * | |
3839 | * On UP it can prevent extra preemption. | |
3840 | */ | |
95cdf3b7 IM |
3841 | void fastcall |
3842 | __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive) | |
1da177e4 LT |
3843 | { |
3844 | unsigned long flags; | |
3845 | int sync = 1; | |
3846 | ||
3847 | if (unlikely(!q)) | |
3848 | return; | |
3849 | ||
3850 | if (unlikely(!nr_exclusive)) | |
3851 | sync = 0; | |
3852 | ||
3853 | spin_lock_irqsave(&q->lock, flags); | |
3854 | __wake_up_common(q, mode, nr_exclusive, sync, NULL); | |
3855 | spin_unlock_irqrestore(&q->lock, flags); | |
3856 | } | |
3857 | EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */ | |
3858 | ||
b15136e9 | 3859 | void complete(struct completion *x) |
1da177e4 LT |
3860 | { |
3861 | unsigned long flags; | |
3862 | ||
3863 | spin_lock_irqsave(&x->wait.lock, flags); | |
3864 | x->done++; | |
3865 | __wake_up_common(&x->wait, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, | |
3866 | 1, 0, NULL); | |
3867 | spin_unlock_irqrestore(&x->wait.lock, flags); | |
3868 | } | |
3869 | EXPORT_SYMBOL(complete); | |
3870 | ||
b15136e9 | 3871 | void complete_all(struct completion *x) |
1da177e4 LT |
3872 | { |
3873 | unsigned long flags; | |
3874 | ||
3875 | spin_lock_irqsave(&x->wait.lock, flags); | |
3876 | x->done += UINT_MAX/2; | |
3877 | __wake_up_common(&x->wait, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, | |
3878 | 0, 0, NULL); | |
3879 | spin_unlock_irqrestore(&x->wait.lock, flags); | |
3880 | } | |
3881 | EXPORT_SYMBOL(complete_all); | |
3882 | ||
8cbbe86d AK |
3883 | static inline long __sched |
3884 | do_wait_for_common(struct completion *x, long timeout, int state) | |
1da177e4 | 3885 | { |
1da177e4 LT |
3886 | if (!x->done) { |
3887 | DECLARE_WAITQUEUE(wait, current); | |
3888 | ||
3889 | wait.flags |= WQ_FLAG_EXCLUSIVE; | |
3890 | __add_wait_queue_tail(&x->wait, &wait); | |
3891 | do { | |
8cbbe86d AK |
3892 | if (state == TASK_INTERRUPTIBLE && |
3893 | signal_pending(current)) { | |
3894 | __remove_wait_queue(&x->wait, &wait); | |
3895 | return -ERESTARTSYS; | |
3896 | } | |
3897 | __set_current_state(state); | |
1da177e4 LT |
3898 | spin_unlock_irq(&x->wait.lock); |
3899 | timeout = schedule_timeout(timeout); | |
3900 | spin_lock_irq(&x->wait.lock); | |
3901 | if (!timeout) { | |
3902 | __remove_wait_queue(&x->wait, &wait); | |
8cbbe86d | 3903 | return timeout; |
1da177e4 LT |
3904 | } |
3905 | } while (!x->done); | |
3906 | __remove_wait_queue(&x->wait, &wait); | |
3907 | } | |
3908 | x->done--; | |
1da177e4 LT |
3909 | return timeout; |
3910 | } | |
1da177e4 | 3911 | |
8cbbe86d AK |
3912 | static long __sched |
3913 | wait_for_common(struct completion *x, long timeout, int state) | |
1da177e4 | 3914 | { |
1da177e4 LT |
3915 | might_sleep(); |
3916 | ||
3917 | spin_lock_irq(&x->wait.lock); | |
8cbbe86d | 3918 | timeout = do_wait_for_common(x, timeout, state); |
1da177e4 | 3919 | spin_unlock_irq(&x->wait.lock); |
8cbbe86d AK |
3920 | return timeout; |
3921 | } | |
1da177e4 | 3922 | |
b15136e9 | 3923 | void __sched wait_for_completion(struct completion *x) |
8cbbe86d AK |
3924 | { |
3925 | wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE); | |
1da177e4 | 3926 | } |
8cbbe86d | 3927 | EXPORT_SYMBOL(wait_for_completion); |
1da177e4 | 3928 | |
b15136e9 | 3929 | unsigned long __sched |
8cbbe86d | 3930 | wait_for_completion_timeout(struct completion *x, unsigned long timeout) |
1da177e4 | 3931 | { |
8cbbe86d | 3932 | return wait_for_common(x, timeout, TASK_UNINTERRUPTIBLE); |
1da177e4 | 3933 | } |
8cbbe86d | 3934 | EXPORT_SYMBOL(wait_for_completion_timeout); |
1da177e4 | 3935 | |
8cbbe86d | 3936 | int __sched wait_for_completion_interruptible(struct completion *x) |
0fec171c | 3937 | { |
51e97990 AK |
3938 | long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_INTERRUPTIBLE); |
3939 | if (t == -ERESTARTSYS) | |
3940 | return t; | |
3941 | return 0; | |
0fec171c | 3942 | } |
8cbbe86d | 3943 | EXPORT_SYMBOL(wait_for_completion_interruptible); |
1da177e4 | 3944 | |
b15136e9 | 3945 | unsigned long __sched |
8cbbe86d AK |
3946 | wait_for_completion_interruptible_timeout(struct completion *x, |
3947 | unsigned long timeout) | |
0fec171c | 3948 | { |
8cbbe86d | 3949 | return wait_for_common(x, timeout, TASK_INTERRUPTIBLE); |
0fec171c | 3950 | } |
8cbbe86d | 3951 | EXPORT_SYMBOL(wait_for_completion_interruptible_timeout); |
1da177e4 | 3952 | |
8cbbe86d AK |
3953 | static long __sched |
3954 | sleep_on_common(wait_queue_head_t *q, int state, long timeout) | |
1da177e4 | 3955 | { |
0fec171c IM |
3956 | unsigned long flags; |
3957 | wait_queue_t wait; | |
3958 | ||
3959 | init_waitqueue_entry(&wait, current); | |
1da177e4 | 3960 | |
8cbbe86d | 3961 | __set_current_state(state); |
1da177e4 | 3962 | |
8cbbe86d AK |
3963 | spin_lock_irqsave(&q->lock, flags); |
3964 | __add_wait_queue(q, &wait); | |
3965 | spin_unlock(&q->lock); | |
3966 | timeout = schedule_timeout(timeout); | |
3967 | spin_lock_irq(&q->lock); | |
3968 | __remove_wait_queue(q, &wait); | |
3969 | spin_unlock_irqrestore(&q->lock, flags); | |
3970 | ||
3971 | return timeout; | |
3972 | } | |
3973 | ||
3974 | void __sched interruptible_sleep_on(wait_queue_head_t *q) | |
3975 | { | |
3976 | sleep_on_common(q, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); | |
1da177e4 | 3977 | } |
1da177e4 LT |
3978 | EXPORT_SYMBOL(interruptible_sleep_on); |
3979 | ||
0fec171c | 3980 | long __sched |
95cdf3b7 | 3981 | interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout) |
1da177e4 | 3982 | { |
8cbbe86d | 3983 | return sleep_on_common(q, TASK_INTERRUPTIBLE, timeout); |
1da177e4 | 3984 | } |
1da177e4 LT |
3985 | EXPORT_SYMBOL(interruptible_sleep_on_timeout); |
3986 | ||
0fec171c | 3987 | void __sched sleep_on(wait_queue_head_t *q) |
1da177e4 | 3988 | { |
8cbbe86d | 3989 | sleep_on_common(q, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); |
1da177e4 | 3990 | } |
1da177e4 LT |
3991 | EXPORT_SYMBOL(sleep_on); |
3992 | ||
0fec171c | 3993 | long __sched sleep_on_timeout(wait_queue_head_t *q, long timeout) |
1da177e4 | 3994 | { |
8cbbe86d | 3995 | return sleep_on_common(q, TASK_UNINTERRUPTIBLE, timeout); |
1da177e4 | 3996 | } |
1da177e4 LT |
3997 | EXPORT_SYMBOL(sleep_on_timeout); |
3998 | ||
b29739f9 IM |
3999 | #ifdef CONFIG_RT_MUTEXES |
4000 | ||
4001 | /* | |
4002 | * rt_mutex_setprio - set the current priority of a task | |
4003 | * @p: task | |
4004 | * @prio: prio value (kernel-internal form) | |
4005 | * | |
4006 | * This function changes the 'effective' priority of a task. It does | |
4007 | * not touch ->normal_prio like __setscheduler(). | |
4008 | * | |
4009 | * Used by the rt_mutex code to implement priority inheritance logic. | |
4010 | */ | |
36c8b586 | 4011 | void rt_mutex_setprio(struct task_struct *p, int prio) |
b29739f9 IM |
4012 | { |
4013 | unsigned long flags; | |
83b699ed | 4014 | int oldprio, on_rq, running; |
70b97a7f | 4015 | struct rq *rq; |
b29739f9 IM |
4016 | |
4017 | BUG_ON(prio < 0 || prio > MAX_PRIO); | |
4018 | ||
4019 | rq = task_rq_lock(p, &flags); | |
a8e504d2 | 4020 | update_rq_clock(rq); |
b29739f9 | 4021 | |
d5f9f942 | 4022 | oldprio = p->prio; |
dd41f596 | 4023 | on_rq = p->se.on_rq; |
83b699ed SV |
4024 | running = task_running(rq, p); |
4025 | if (on_rq) { | |
69be72c1 | 4026 | dequeue_task(rq, p, 0); |
83b699ed SV |
4027 | if (running) |
4028 | p->sched_class->put_prev_task(rq, p); | |
4029 | } | |
dd41f596 IM |
4030 | |
4031 | if (rt_prio(prio)) | |
4032 | p->sched_class = &rt_sched_class; | |
4033 | else | |
4034 | p->sched_class = &fair_sched_class; | |
4035 | ||
b29739f9 IM |
4036 | p->prio = prio; |
4037 | ||
dd41f596 | 4038 | if (on_rq) { |
83b699ed SV |
4039 | if (running) |
4040 | p->sched_class->set_curr_task(rq); | |
8159f87e | 4041 | enqueue_task(rq, p, 0); |
b29739f9 IM |
4042 | /* |
4043 | * Reschedule if we are currently running on this runqueue and | |
d5f9f942 AM |
4044 | * our priority decreased, or if we are not currently running on |
4045 | * this runqueue and our priority is higher than the current's | |
b29739f9 | 4046 | */ |
83b699ed | 4047 | if (running) { |
d5f9f942 AM |
4048 | if (p->prio > oldprio) |
4049 | resched_task(rq->curr); | |
dd41f596 IM |
4050 | } else { |
4051 | check_preempt_curr(rq, p); | |
4052 | } | |
b29739f9 IM |
4053 | } |
4054 | task_rq_unlock(rq, &flags); | |
4055 | } | |
4056 | ||
4057 | #endif | |
4058 | ||
36c8b586 | 4059 | void set_user_nice(struct task_struct *p, long nice) |
1da177e4 | 4060 | { |
dd41f596 | 4061 | int old_prio, delta, on_rq; |
1da177e4 | 4062 | unsigned long flags; |
70b97a7f | 4063 | struct rq *rq; |
1da177e4 LT |
4064 | |
4065 | if (TASK_NICE(p) == nice || nice < -20 || nice > 19) | |
4066 | return; | |
4067 | /* | |
4068 | * We have to be careful, if called from sys_setpriority(), | |
4069 | * the task might be in the middle of scheduling on another CPU. | |
4070 | */ | |
4071 | rq = task_rq_lock(p, &flags); | |
a8e504d2 | 4072 | update_rq_clock(rq); |
1da177e4 LT |
4073 | /* |
4074 | * The RT priorities are set via sched_setscheduler(), but we still | |
4075 | * allow the 'normal' nice value to be set - but as expected | |
4076 | * it wont have any effect on scheduling until the task is | |
dd41f596 | 4077 | * SCHED_FIFO/SCHED_RR: |
1da177e4 | 4078 | */ |
e05606d3 | 4079 | if (task_has_rt_policy(p)) { |
1da177e4 LT |
4080 | p->static_prio = NICE_TO_PRIO(nice); |
4081 | goto out_unlock; | |
4082 | } | |
dd41f596 IM |
4083 | on_rq = p->se.on_rq; |
4084 | if (on_rq) { | |
69be72c1 | 4085 | dequeue_task(rq, p, 0); |
79b5dddf | 4086 | dec_load(rq, p); |
2dd73a4f | 4087 | } |
1da177e4 | 4088 | |
1da177e4 | 4089 | p->static_prio = NICE_TO_PRIO(nice); |
2dd73a4f | 4090 | set_load_weight(p); |
b29739f9 IM |
4091 | old_prio = p->prio; |
4092 | p->prio = effective_prio(p); | |
4093 | delta = p->prio - old_prio; | |
1da177e4 | 4094 | |
dd41f596 | 4095 | if (on_rq) { |
8159f87e | 4096 | enqueue_task(rq, p, 0); |
29b4b623 | 4097 | inc_load(rq, p); |
1da177e4 | 4098 | /* |
d5f9f942 AM |
4099 | * If the task increased its priority or is running and |
4100 | * lowered its priority, then reschedule its CPU: | |
1da177e4 | 4101 | */ |
d5f9f942 | 4102 | if (delta < 0 || (delta > 0 && task_running(rq, p))) |
1da177e4 LT |
4103 | resched_task(rq->curr); |
4104 | } | |
4105 | out_unlock: | |
4106 | task_rq_unlock(rq, &flags); | |
4107 | } | |
1da177e4 LT |
4108 | EXPORT_SYMBOL(set_user_nice); |
4109 | ||
e43379f1 MM |
4110 | /* |
4111 | * can_nice - check if a task can reduce its nice value | |
4112 | * @p: task | |
4113 | * @nice: nice value | |
4114 | */ | |
36c8b586 | 4115 | int can_nice(const struct task_struct *p, const int nice) |
e43379f1 | 4116 | { |
024f4747 MM |
4117 | /* convert nice value [19,-20] to rlimit style value [1,40] */ |
4118 | int nice_rlim = 20 - nice; | |
48f24c4d | 4119 | |
e43379f1 MM |
4120 | return (nice_rlim <= p->signal->rlim[RLIMIT_NICE].rlim_cur || |
4121 | capable(CAP_SYS_NICE)); | |
4122 | } | |
4123 | ||
1da177e4 LT |
4124 | #ifdef __ARCH_WANT_SYS_NICE |
4125 | ||
4126 | /* | |
4127 | * sys_nice - change the priority of the current process. | |
4128 | * @increment: priority increment | |
4129 | * | |
4130 | * sys_setpriority is a more generic, but much slower function that | |
4131 | * does similar things. | |
4132 | */ | |
4133 | asmlinkage long sys_nice(int increment) | |
4134 | { | |
48f24c4d | 4135 | long nice, retval; |
1da177e4 LT |
4136 | |
4137 | /* | |
4138 | * Setpriority might change our priority at the same moment. | |
4139 | * We don't have to worry. Conceptually one call occurs first | |
4140 | * and we have a single winner. | |
4141 | */ | |
e43379f1 MM |
4142 | if (increment < -40) |
4143 | increment = -40; | |
1da177e4 LT |
4144 | if (increment > 40) |
4145 | increment = 40; | |
4146 | ||
4147 | nice = PRIO_TO_NICE(current->static_prio) + increment; | |
4148 | if (nice < -20) | |
4149 | nice = -20; | |
4150 | if (nice > 19) | |
4151 | nice = 19; | |
4152 | ||
e43379f1 MM |
4153 | if (increment < 0 && !can_nice(current, nice)) |
4154 | return -EPERM; | |
4155 | ||
1da177e4 LT |
4156 | retval = security_task_setnice(current, nice); |
4157 | if (retval) | |
4158 | return retval; | |
4159 | ||
4160 | set_user_nice(current, nice); | |
4161 | return 0; | |
4162 | } | |
4163 | ||
4164 | #endif | |
4165 | ||
4166 | /** | |
4167 | * task_prio - return the priority value of a given task. | |
4168 | * @p: the task in question. | |
4169 | * | |
4170 | * This is the priority value as seen by users in /proc. | |
4171 | * RT tasks are offset by -200. Normal tasks are centered | |
4172 | * around 0, value goes from -16 to +15. | |
4173 | */ | |
36c8b586 | 4174 | int task_prio(const struct task_struct *p) |
1da177e4 LT |
4175 | { |
4176 | return p->prio - MAX_RT_PRIO; | |
4177 | } | |
4178 | ||
4179 | /** | |
4180 | * task_nice - return the nice value of a given task. | |
4181 | * @p: the task in question. | |
4182 | */ | |
36c8b586 | 4183 | int task_nice(const struct task_struct *p) |
1da177e4 LT |
4184 | { |
4185 | return TASK_NICE(p); | |
4186 | } | |
1da177e4 | 4187 | EXPORT_SYMBOL_GPL(task_nice); |
1da177e4 LT |
4188 | |
4189 | /** | |
4190 | * idle_cpu - is a given cpu idle currently? | |
4191 | * @cpu: the processor in question. | |
4192 | */ | |
4193 | int idle_cpu(int cpu) | |
4194 | { | |
4195 | return cpu_curr(cpu) == cpu_rq(cpu)->idle; | |
4196 | } | |
4197 | ||
1da177e4 LT |
4198 | /** |
4199 | * idle_task - return the idle task for a given cpu. | |
4200 | * @cpu: the processor in question. | |
4201 | */ | |
36c8b586 | 4202 | struct task_struct *idle_task(int cpu) |
1da177e4 LT |
4203 | { |
4204 | return cpu_rq(cpu)->idle; | |
4205 | } | |
4206 | ||
4207 | /** | |
4208 | * find_process_by_pid - find a process with a matching PID value. | |
4209 | * @pid: the pid in question. | |
4210 | */ | |
a9957449 | 4211 | static struct task_struct *find_process_by_pid(pid_t pid) |
1da177e4 | 4212 | { |
228ebcbe | 4213 | return pid ? find_task_by_vpid(pid) : current; |
1da177e4 LT |
4214 | } |
4215 | ||
4216 | /* Actually do priority change: must hold rq lock. */ | |
dd41f596 IM |
4217 | static void |
4218 | __setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio) | |
1da177e4 | 4219 | { |
dd41f596 | 4220 | BUG_ON(p->se.on_rq); |
48f24c4d | 4221 | |
1da177e4 | 4222 | p->policy = policy; |
dd41f596 IM |
4223 | switch (p->policy) { |
4224 | case SCHED_NORMAL: | |
4225 | case SCHED_BATCH: | |
4226 | case SCHED_IDLE: | |
4227 | p->sched_class = &fair_sched_class; | |
4228 | break; | |
4229 | case SCHED_FIFO: | |
4230 | case SCHED_RR: | |
4231 | p->sched_class = &rt_sched_class; | |
4232 | break; | |
4233 | } | |
4234 | ||
1da177e4 | 4235 | p->rt_priority = prio; |
b29739f9 IM |
4236 | p->normal_prio = normal_prio(p); |
4237 | /* we are holding p->pi_lock already */ | |
4238 | p->prio = rt_mutex_getprio(p); | |
2dd73a4f | 4239 | set_load_weight(p); |
1da177e4 LT |
4240 | } |
4241 | ||
4242 | /** | |
72fd4a35 | 4243 | * sched_setscheduler - change the scheduling policy and/or RT priority of a thread. |
1da177e4 LT |
4244 | * @p: the task in question. |
4245 | * @policy: new policy. | |
4246 | * @param: structure containing the new RT priority. | |
5fe1d75f | 4247 | * |
72fd4a35 | 4248 | * NOTE that the task may be already dead. |
1da177e4 | 4249 | */ |
95cdf3b7 IM |
4250 | int sched_setscheduler(struct task_struct *p, int policy, |
4251 | struct sched_param *param) | |
1da177e4 | 4252 | { |
83b699ed | 4253 | int retval, oldprio, oldpolicy = -1, on_rq, running; |
1da177e4 | 4254 | unsigned long flags; |
70b97a7f | 4255 | struct rq *rq; |
1da177e4 | 4256 | |
66e5393a SR |
4257 | /* may grab non-irq protected spin_locks */ |
4258 | BUG_ON(in_interrupt()); | |
1da177e4 LT |
4259 | recheck: |
4260 | /* double check policy once rq lock held */ | |
4261 | if (policy < 0) | |
4262 | policy = oldpolicy = p->policy; | |
4263 | else if (policy != SCHED_FIFO && policy != SCHED_RR && | |
dd41f596 IM |
4264 | policy != SCHED_NORMAL && policy != SCHED_BATCH && |
4265 | policy != SCHED_IDLE) | |
b0a9499c | 4266 | return -EINVAL; |
1da177e4 LT |
4267 | /* |
4268 | * Valid priorities for SCHED_FIFO and SCHED_RR are | |
dd41f596 IM |
4269 | * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL, |
4270 | * SCHED_BATCH and SCHED_IDLE is 0. | |
1da177e4 LT |
4271 | */ |
4272 | if (param->sched_priority < 0 || | |
95cdf3b7 | 4273 | (p->mm && param->sched_priority > MAX_USER_RT_PRIO-1) || |
d46523ea | 4274 | (!p->mm && param->sched_priority > MAX_RT_PRIO-1)) |
1da177e4 | 4275 | return -EINVAL; |
e05606d3 | 4276 | if (rt_policy(policy) != (param->sched_priority != 0)) |
1da177e4 LT |
4277 | return -EINVAL; |
4278 | ||
37e4ab3f OC |
4279 | /* |
4280 | * Allow unprivileged RT tasks to decrease priority: | |
4281 | */ | |
4282 | if (!capable(CAP_SYS_NICE)) { | |
e05606d3 | 4283 | if (rt_policy(policy)) { |
8dc3e909 | 4284 | unsigned long rlim_rtprio; |
8dc3e909 ON |
4285 | |
4286 | if (!lock_task_sighand(p, &flags)) | |
4287 | return -ESRCH; | |
4288 | rlim_rtprio = p->signal->rlim[RLIMIT_RTPRIO].rlim_cur; | |
4289 | unlock_task_sighand(p, &flags); | |
4290 | ||
4291 | /* can't set/change the rt policy */ | |
4292 | if (policy != p->policy && !rlim_rtprio) | |
4293 | return -EPERM; | |
4294 | ||
4295 | /* can't increase priority */ | |
4296 | if (param->sched_priority > p->rt_priority && | |
4297 | param->sched_priority > rlim_rtprio) | |
4298 | return -EPERM; | |
4299 | } | |
dd41f596 IM |
4300 | /* |
4301 | * Like positive nice levels, dont allow tasks to | |
4302 | * move out of SCHED_IDLE either: | |
4303 | */ | |
4304 | if (p->policy == SCHED_IDLE && policy != SCHED_IDLE) | |
4305 | return -EPERM; | |
5fe1d75f | 4306 | |
37e4ab3f OC |
4307 | /* can't change other user's priorities */ |
4308 | if ((current->euid != p->euid) && | |
4309 | (current->euid != p->uid)) | |
4310 | return -EPERM; | |
4311 | } | |
1da177e4 LT |
4312 | |
4313 | retval = security_task_setscheduler(p, policy, param); | |
4314 | if (retval) | |
4315 | return retval; | |
b29739f9 IM |
4316 | /* |
4317 | * make sure no PI-waiters arrive (or leave) while we are | |
4318 | * changing the priority of the task: | |
4319 | */ | |
4320 | spin_lock_irqsave(&p->pi_lock, flags); | |
1da177e4 LT |
4321 | /* |
4322 | * To be able to change p->policy safely, the apropriate | |
4323 | * runqueue lock must be held. | |
4324 | */ | |
b29739f9 | 4325 | rq = __task_rq_lock(p); |
1da177e4 LT |
4326 | /* recheck policy now with rq lock held */ |
4327 | if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) { | |
4328 | policy = oldpolicy = -1; | |
b29739f9 IM |
4329 | __task_rq_unlock(rq); |
4330 | spin_unlock_irqrestore(&p->pi_lock, flags); | |
1da177e4 LT |
4331 | goto recheck; |
4332 | } | |
2daa3577 | 4333 | update_rq_clock(rq); |
dd41f596 | 4334 | on_rq = p->se.on_rq; |
83b699ed SV |
4335 | running = task_running(rq, p); |
4336 | if (on_rq) { | |
2e1cb74a | 4337 | deactivate_task(rq, p, 0); |
83b699ed SV |
4338 | if (running) |
4339 | p->sched_class->put_prev_task(rq, p); | |
4340 | } | |
f6b53205 | 4341 | |
1da177e4 | 4342 | oldprio = p->prio; |
dd41f596 | 4343 | __setscheduler(rq, p, policy, param->sched_priority); |
f6b53205 | 4344 | |
dd41f596 | 4345 | if (on_rq) { |
83b699ed SV |
4346 | if (running) |
4347 | p->sched_class->set_curr_task(rq); | |
dd41f596 | 4348 | activate_task(rq, p, 0); |
1da177e4 LT |
4349 | /* |
4350 | * Reschedule if we are currently running on this runqueue and | |
d5f9f942 AM |
4351 | * our priority decreased, or if we are not currently running on |
4352 | * this runqueue and our priority is higher than the current's | |
1da177e4 | 4353 | */ |
83b699ed | 4354 | if (running) { |
d5f9f942 AM |
4355 | if (p->prio > oldprio) |
4356 | resched_task(rq->curr); | |
dd41f596 IM |
4357 | } else { |
4358 | check_preempt_curr(rq, p); | |
4359 | } | |
1da177e4 | 4360 | } |
b29739f9 IM |
4361 | __task_rq_unlock(rq); |
4362 | spin_unlock_irqrestore(&p->pi_lock, flags); | |
4363 | ||
95e02ca9 TG |
4364 | rt_mutex_adjust_pi(p); |
4365 | ||
1da177e4 LT |
4366 | return 0; |
4367 | } | |
4368 | EXPORT_SYMBOL_GPL(sched_setscheduler); | |
4369 | ||
95cdf3b7 IM |
4370 | static int |
4371 | do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param) | |
1da177e4 | 4372 | { |
1da177e4 LT |
4373 | struct sched_param lparam; |
4374 | struct task_struct *p; | |
36c8b586 | 4375 | int retval; |
1da177e4 LT |
4376 | |
4377 | if (!param || pid < 0) | |
4378 | return -EINVAL; | |
4379 | if (copy_from_user(&lparam, param, sizeof(struct sched_param))) | |
4380 | return -EFAULT; | |
5fe1d75f ON |
4381 | |
4382 | rcu_read_lock(); | |
4383 | retval = -ESRCH; | |
1da177e4 | 4384 | p = find_process_by_pid(pid); |
5fe1d75f ON |
4385 | if (p != NULL) |
4386 | retval = sched_setscheduler(p, policy, &lparam); | |
4387 | rcu_read_unlock(); | |
36c8b586 | 4388 | |
1da177e4 LT |
4389 | return retval; |
4390 | } | |
4391 | ||
4392 | /** | |
4393 | * sys_sched_setscheduler - set/change the scheduler policy and RT priority | |
4394 | * @pid: the pid in question. | |
4395 | * @policy: new policy. | |
4396 | * @param: structure containing the new RT priority. | |
4397 | */ | |
41a2d6cf IM |
4398 | asmlinkage long |
4399 | sys_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param) | |
1da177e4 | 4400 | { |
c21761f1 JB |
4401 | /* negative values for policy are not valid */ |
4402 | if (policy < 0) | |
4403 | return -EINVAL; | |
4404 | ||
1da177e4 LT |
4405 | return do_sched_setscheduler(pid, policy, param); |
4406 | } | |
4407 | ||
4408 | /** | |
4409 | * sys_sched_setparam - set/change the RT priority of a thread | |
4410 | * @pid: the pid in question. | |
4411 | * @param: structure containing the new RT priority. | |
4412 | */ | |
4413 | asmlinkage long sys_sched_setparam(pid_t pid, struct sched_param __user *param) | |
4414 | { | |
4415 | return do_sched_setscheduler(pid, -1, param); | |
4416 | } | |
4417 | ||
4418 | /** | |
4419 | * sys_sched_getscheduler - get the policy (scheduling class) of a thread | |
4420 | * @pid: the pid in question. | |
4421 | */ | |
4422 | asmlinkage long sys_sched_getscheduler(pid_t pid) | |
4423 | { | |
36c8b586 | 4424 | struct task_struct *p; |
3a5c359a | 4425 | int retval; |
1da177e4 LT |
4426 | |
4427 | if (pid < 0) | |
3a5c359a | 4428 | return -EINVAL; |
1da177e4 LT |
4429 | |
4430 | retval = -ESRCH; | |
4431 | read_lock(&tasklist_lock); | |
4432 | p = find_process_by_pid(pid); | |
4433 | if (p) { | |
4434 | retval = security_task_getscheduler(p); | |
4435 | if (!retval) | |
4436 | retval = p->policy; | |
4437 | } | |
4438 | read_unlock(&tasklist_lock); | |
1da177e4 LT |
4439 | return retval; |
4440 | } | |
4441 | ||
4442 | /** | |
4443 | * sys_sched_getscheduler - get the RT priority of a thread | |
4444 | * @pid: the pid in question. | |
4445 | * @param: structure containing the RT priority. | |
4446 | */ | |
4447 | asmlinkage long sys_sched_getparam(pid_t pid, struct sched_param __user *param) | |
4448 | { | |
4449 | struct sched_param lp; | |
36c8b586 | 4450 | struct task_struct *p; |
3a5c359a | 4451 | int retval; |
1da177e4 LT |
4452 | |
4453 | if (!param || pid < 0) | |
3a5c359a | 4454 | return -EINVAL; |
1da177e4 LT |
4455 | |
4456 | read_lock(&tasklist_lock); | |
4457 | p = find_process_by_pid(pid); | |
4458 | retval = -ESRCH; | |
4459 | if (!p) | |
4460 | goto out_unlock; | |
4461 | ||
4462 | retval = security_task_getscheduler(p); | |
4463 | if (retval) | |
4464 | goto out_unlock; | |
4465 | ||
4466 | lp.sched_priority = p->rt_priority; | |
4467 | read_unlock(&tasklist_lock); | |
4468 | ||
4469 | /* | |
4470 | * This one might sleep, we cannot do it with a spinlock held ... | |
4471 | */ | |
4472 | retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0; | |
4473 | ||
1da177e4 LT |
4474 | return retval; |
4475 | ||
4476 | out_unlock: | |
4477 | read_unlock(&tasklist_lock); | |
4478 | return retval; | |
4479 | } | |
4480 | ||
4481 | long sched_setaffinity(pid_t pid, cpumask_t new_mask) | |
4482 | { | |
1da177e4 | 4483 | cpumask_t cpus_allowed; |
36c8b586 IM |
4484 | struct task_struct *p; |
4485 | int retval; | |
1da177e4 | 4486 | |
5be9361c | 4487 | mutex_lock(&sched_hotcpu_mutex); |
1da177e4 LT |
4488 | read_lock(&tasklist_lock); |
4489 | ||
4490 | p = find_process_by_pid(pid); | |
4491 | if (!p) { | |
4492 | read_unlock(&tasklist_lock); | |
5be9361c | 4493 | mutex_unlock(&sched_hotcpu_mutex); |
1da177e4 LT |
4494 | return -ESRCH; |
4495 | } | |
4496 | ||
4497 | /* | |
4498 | * It is not safe to call set_cpus_allowed with the | |
41a2d6cf | 4499 | * tasklist_lock held. We will bump the task_struct's |
1da177e4 LT |
4500 | * usage count and then drop tasklist_lock. |
4501 | */ | |
4502 | get_task_struct(p); | |
4503 | read_unlock(&tasklist_lock); | |
4504 | ||
4505 | retval = -EPERM; | |
4506 | if ((current->euid != p->euid) && (current->euid != p->uid) && | |
4507 | !capable(CAP_SYS_NICE)) | |
4508 | goto out_unlock; | |
4509 | ||
e7834f8f DQ |
4510 | retval = security_task_setscheduler(p, 0, NULL); |
4511 | if (retval) | |
4512 | goto out_unlock; | |
4513 | ||
1da177e4 LT |
4514 | cpus_allowed = cpuset_cpus_allowed(p); |
4515 | cpus_and(new_mask, new_mask, cpus_allowed); | |
8707d8b8 | 4516 | again: |
1da177e4 LT |
4517 | retval = set_cpus_allowed(p, new_mask); |
4518 | ||
8707d8b8 PM |
4519 | if (!retval) { |
4520 | cpus_allowed = cpuset_cpus_allowed(p); | |
4521 | if (!cpus_subset(new_mask, cpus_allowed)) { | |
4522 | /* | |
4523 | * We must have raced with a concurrent cpuset | |
4524 | * update. Just reset the cpus_allowed to the | |
4525 | * cpuset's cpus_allowed | |
4526 | */ | |
4527 | new_mask = cpus_allowed; | |
4528 | goto again; | |
4529 | } | |
4530 | } | |
1da177e4 LT |
4531 | out_unlock: |
4532 | put_task_struct(p); | |
5be9361c | 4533 | mutex_unlock(&sched_hotcpu_mutex); |
1da177e4 LT |
4534 | return retval; |
4535 | } | |
4536 | ||
4537 | static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len, | |
4538 | cpumask_t *new_mask) | |
4539 | { | |
4540 | if (len < sizeof(cpumask_t)) { | |
4541 | memset(new_mask, 0, sizeof(cpumask_t)); | |
4542 | } else if (len > sizeof(cpumask_t)) { | |
4543 | len = sizeof(cpumask_t); | |
4544 | } | |
4545 | return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0; | |
4546 | } | |
4547 | ||
4548 | /** | |
4549 | * sys_sched_setaffinity - set the cpu affinity of a process | |
4550 | * @pid: pid of the process | |
4551 | * @len: length in bytes of the bitmask pointed to by user_mask_ptr | |
4552 | * @user_mask_ptr: user-space pointer to the new cpu mask | |
4553 | */ | |
4554 | asmlinkage long sys_sched_setaffinity(pid_t pid, unsigned int len, | |
4555 | unsigned long __user *user_mask_ptr) | |
4556 | { | |
4557 | cpumask_t new_mask; | |
4558 | int retval; | |
4559 | ||
4560 | retval = get_user_cpu_mask(user_mask_ptr, len, &new_mask); | |
4561 | if (retval) | |
4562 | return retval; | |
4563 | ||
4564 | return sched_setaffinity(pid, new_mask); | |
4565 | } | |
4566 | ||
4567 | /* | |
4568 | * Represents all cpu's present in the system | |
4569 | * In systems capable of hotplug, this map could dynamically grow | |
4570 | * as new cpu's are detected in the system via any platform specific | |
4571 | * method, such as ACPI for e.g. | |
4572 | */ | |
4573 | ||
4cef0c61 | 4574 | cpumask_t cpu_present_map __read_mostly; |
1da177e4 LT |
4575 | EXPORT_SYMBOL(cpu_present_map); |
4576 | ||
4577 | #ifndef CONFIG_SMP | |
4cef0c61 | 4578 | cpumask_t cpu_online_map __read_mostly = CPU_MASK_ALL; |
e16b38f7 GB |
4579 | EXPORT_SYMBOL(cpu_online_map); |
4580 | ||
4cef0c61 | 4581 | cpumask_t cpu_possible_map __read_mostly = CPU_MASK_ALL; |
e16b38f7 | 4582 | EXPORT_SYMBOL(cpu_possible_map); |
1da177e4 LT |
4583 | #endif |
4584 | ||
4585 | long sched_getaffinity(pid_t pid, cpumask_t *mask) | |
4586 | { | |
36c8b586 | 4587 | struct task_struct *p; |
1da177e4 | 4588 | int retval; |
1da177e4 | 4589 | |
5be9361c | 4590 | mutex_lock(&sched_hotcpu_mutex); |
1da177e4 LT |
4591 | read_lock(&tasklist_lock); |
4592 | ||
4593 | retval = -ESRCH; | |
4594 | p = find_process_by_pid(pid); | |
4595 | if (!p) | |
4596 | goto out_unlock; | |
4597 | ||
e7834f8f DQ |
4598 | retval = security_task_getscheduler(p); |
4599 | if (retval) | |
4600 | goto out_unlock; | |
4601 | ||
2f7016d9 | 4602 | cpus_and(*mask, p->cpus_allowed, cpu_online_map); |
1da177e4 LT |
4603 | |
4604 | out_unlock: | |
4605 | read_unlock(&tasklist_lock); | |
5be9361c | 4606 | mutex_unlock(&sched_hotcpu_mutex); |
1da177e4 | 4607 | |
9531b62f | 4608 | return retval; |
1da177e4 LT |
4609 | } |
4610 | ||
4611 | /** | |
4612 | * sys_sched_getaffinity - get the cpu affinity of a process | |
4613 | * @pid: pid of the process | |
4614 | * @len: length in bytes of the bitmask pointed to by user_mask_ptr | |
4615 | * @user_mask_ptr: user-space pointer to hold the current cpu mask | |
4616 | */ | |
4617 | asmlinkage long sys_sched_getaffinity(pid_t pid, unsigned int len, | |
4618 | unsigned long __user *user_mask_ptr) | |
4619 | { | |
4620 | int ret; | |
4621 | cpumask_t mask; | |
4622 | ||
4623 | if (len < sizeof(cpumask_t)) | |
4624 | return -EINVAL; | |
4625 | ||
4626 | ret = sched_getaffinity(pid, &mask); | |
4627 | if (ret < 0) | |
4628 | return ret; | |
4629 | ||
4630 | if (copy_to_user(user_mask_ptr, &mask, sizeof(cpumask_t))) | |
4631 | return -EFAULT; | |
4632 | ||
4633 | return sizeof(cpumask_t); | |
4634 | } | |
4635 | ||
4636 | /** | |
4637 | * sys_sched_yield - yield the current processor to other threads. | |
4638 | * | |
dd41f596 IM |
4639 | * This function yields the current CPU to other tasks. If there are no |
4640 | * other threads running on this CPU then this function will return. | |
1da177e4 LT |
4641 | */ |
4642 | asmlinkage long sys_sched_yield(void) | |
4643 | { | |
70b97a7f | 4644 | struct rq *rq = this_rq_lock(); |
1da177e4 | 4645 | |
2d72376b | 4646 | schedstat_inc(rq, yld_count); |
4530d7ab | 4647 | current->sched_class->yield_task(rq); |
1da177e4 LT |
4648 | |
4649 | /* | |
4650 | * Since we are going to call schedule() anyway, there's | |
4651 | * no need to preempt or enable interrupts: | |
4652 | */ | |
4653 | __release(rq->lock); | |
8a25d5de | 4654 | spin_release(&rq->lock.dep_map, 1, _THIS_IP_); |
1da177e4 LT |
4655 | _raw_spin_unlock(&rq->lock); |
4656 | preempt_enable_no_resched(); | |
4657 | ||
4658 | schedule(); | |
4659 | ||
4660 | return 0; | |
4661 | } | |
4662 | ||
e7b38404 | 4663 | static void __cond_resched(void) |
1da177e4 | 4664 | { |
8e0a43d8 IM |
4665 | #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP |
4666 | __might_sleep(__FILE__, __LINE__); | |
4667 | #endif | |
5bbcfd90 IM |
4668 | /* |
4669 | * The BKS might be reacquired before we have dropped | |
4670 | * PREEMPT_ACTIVE, which could trigger a second | |
4671 | * cond_resched() call. | |
4672 | */ | |
1da177e4 LT |
4673 | do { |
4674 | add_preempt_count(PREEMPT_ACTIVE); | |
4675 | schedule(); | |
4676 | sub_preempt_count(PREEMPT_ACTIVE); | |
4677 | } while (need_resched()); | |
4678 | } | |
4679 | ||
4680 | int __sched cond_resched(void) | |
4681 | { | |
9414232f IM |
4682 | if (need_resched() && !(preempt_count() & PREEMPT_ACTIVE) && |
4683 | system_state == SYSTEM_RUNNING) { | |
1da177e4 LT |
4684 | __cond_resched(); |
4685 | return 1; | |
4686 | } | |
4687 | return 0; | |
4688 | } | |
1da177e4 LT |
4689 | EXPORT_SYMBOL(cond_resched); |
4690 | ||
4691 | /* | |
4692 | * cond_resched_lock() - if a reschedule is pending, drop the given lock, | |
4693 | * call schedule, and on return reacquire the lock. | |
4694 | * | |
41a2d6cf | 4695 | * This works OK both with and without CONFIG_PREEMPT. We do strange low-level |
1da177e4 LT |
4696 | * operations here to prevent schedule() from being called twice (once via |
4697 | * spin_unlock(), once by hand). | |
4698 | */ | |
95cdf3b7 | 4699 | int cond_resched_lock(spinlock_t *lock) |
1da177e4 | 4700 | { |
6df3cecb JK |
4701 | int ret = 0; |
4702 | ||
1da177e4 LT |
4703 | if (need_lockbreak(lock)) { |
4704 | spin_unlock(lock); | |
4705 | cpu_relax(); | |
6df3cecb | 4706 | ret = 1; |
1da177e4 LT |
4707 | spin_lock(lock); |
4708 | } | |
9414232f | 4709 | if (need_resched() && system_state == SYSTEM_RUNNING) { |
8a25d5de | 4710 | spin_release(&lock->dep_map, 1, _THIS_IP_); |
1da177e4 LT |
4711 | _raw_spin_unlock(lock); |
4712 | preempt_enable_no_resched(); | |
4713 | __cond_resched(); | |
6df3cecb | 4714 | ret = 1; |
1da177e4 | 4715 | spin_lock(lock); |
1da177e4 | 4716 | } |
6df3cecb | 4717 | return ret; |
1da177e4 | 4718 | } |
1da177e4 LT |
4719 | EXPORT_SYMBOL(cond_resched_lock); |
4720 | ||
4721 | int __sched cond_resched_softirq(void) | |
4722 | { | |
4723 | BUG_ON(!in_softirq()); | |
4724 | ||
9414232f | 4725 | if (need_resched() && system_state == SYSTEM_RUNNING) { |
98d82567 | 4726 | local_bh_enable(); |
1da177e4 LT |
4727 | __cond_resched(); |
4728 | local_bh_disable(); | |
4729 | return 1; | |
4730 | } | |
4731 | return 0; | |
4732 | } | |
1da177e4 LT |
4733 | EXPORT_SYMBOL(cond_resched_softirq); |
4734 | ||
1da177e4 LT |
4735 | /** |
4736 | * yield - yield the current processor to other threads. | |
4737 | * | |
72fd4a35 | 4738 | * This is a shortcut for kernel-space yielding - it marks the |
1da177e4 LT |
4739 | * thread runnable and calls sys_sched_yield(). |
4740 | */ | |
4741 | void __sched yield(void) | |
4742 | { | |
4743 | set_current_state(TASK_RUNNING); | |
4744 | sys_sched_yield(); | |
4745 | } | |
1da177e4 LT |
4746 | EXPORT_SYMBOL(yield); |
4747 | ||
4748 | /* | |
41a2d6cf | 4749 | * This task is about to go to sleep on IO. Increment rq->nr_iowait so |
1da177e4 LT |
4750 | * that process accounting knows that this is a task in IO wait state. |
4751 | * | |
4752 | * But don't do that if it is a deliberate, throttling IO wait (this task | |
4753 | * has set its backing_dev_info: the queue against which it should throttle) | |
4754 | */ | |
4755 | void __sched io_schedule(void) | |
4756 | { | |
70b97a7f | 4757 | struct rq *rq = &__raw_get_cpu_var(runqueues); |
1da177e4 | 4758 | |
0ff92245 | 4759 | delayacct_blkio_start(); |
1da177e4 LT |
4760 | atomic_inc(&rq->nr_iowait); |
4761 | schedule(); | |
4762 | atomic_dec(&rq->nr_iowait); | |
0ff92245 | 4763 | delayacct_blkio_end(); |
1da177e4 | 4764 | } |
1da177e4 LT |
4765 | EXPORT_SYMBOL(io_schedule); |
4766 | ||
4767 | long __sched io_schedule_timeout(long timeout) | |
4768 | { | |
70b97a7f | 4769 | struct rq *rq = &__raw_get_cpu_var(runqueues); |
1da177e4 LT |
4770 | long ret; |
4771 | ||
0ff92245 | 4772 | delayacct_blkio_start(); |
1da177e4 LT |
4773 | atomic_inc(&rq->nr_iowait); |
4774 | ret = schedule_timeout(timeout); | |
4775 | atomic_dec(&rq->nr_iowait); | |
0ff92245 | 4776 | delayacct_blkio_end(); |
1da177e4 LT |
4777 | return ret; |
4778 | } | |
4779 | ||
4780 | /** | |
4781 | * sys_sched_get_priority_max - return maximum RT priority. | |
4782 | * @policy: scheduling class. | |
4783 | * | |
4784 | * this syscall returns the maximum rt_priority that can be used | |
4785 | * by a given scheduling class. | |
4786 | */ | |
4787 | asmlinkage long sys_sched_get_priority_max(int policy) | |
4788 | { | |
4789 | int ret = -EINVAL; | |
4790 | ||
4791 | switch (policy) { | |
4792 | case SCHED_FIFO: | |
4793 | case SCHED_RR: | |
4794 | ret = MAX_USER_RT_PRIO-1; | |
4795 | break; | |
4796 | case SCHED_NORMAL: | |
b0a9499c | 4797 | case SCHED_BATCH: |
dd41f596 | 4798 | case SCHED_IDLE: |
1da177e4 LT |
4799 | ret = 0; |
4800 | break; | |
4801 | } | |
4802 | return ret; | |
4803 | } | |
4804 | ||
4805 | /** | |
4806 | * sys_sched_get_priority_min - return minimum RT priority. | |
4807 | * @policy: scheduling class. | |
4808 | * | |
4809 | * this syscall returns the minimum rt_priority that can be used | |
4810 | * by a given scheduling class. | |
4811 | */ | |
4812 | asmlinkage long sys_sched_get_priority_min(int policy) | |
4813 | { | |
4814 | int ret = -EINVAL; | |
4815 | ||
4816 | switch (policy) { | |
4817 | case SCHED_FIFO: | |
4818 | case SCHED_RR: | |
4819 | ret = 1; | |
4820 | break; | |
4821 | case SCHED_NORMAL: | |
b0a9499c | 4822 | case SCHED_BATCH: |
dd41f596 | 4823 | case SCHED_IDLE: |
1da177e4 LT |
4824 | ret = 0; |
4825 | } | |
4826 | return ret; | |
4827 | } | |
4828 | ||
4829 | /** | |
4830 | * sys_sched_rr_get_interval - return the default timeslice of a process. | |
4831 | * @pid: pid of the process. | |
4832 | * @interval: userspace pointer to the timeslice value. | |
4833 | * | |
4834 | * this syscall writes the default timeslice value of a given process | |
4835 | * into the user-space timespec buffer. A value of '0' means infinity. | |
4836 | */ | |
4837 | asmlinkage | |
4838 | long sys_sched_rr_get_interval(pid_t pid, struct timespec __user *interval) | |
4839 | { | |
36c8b586 | 4840 | struct task_struct *p; |
a4ec24b4 | 4841 | unsigned int time_slice; |
3a5c359a | 4842 | int retval; |
1da177e4 | 4843 | struct timespec t; |
1da177e4 LT |
4844 | |
4845 | if (pid < 0) | |
3a5c359a | 4846 | return -EINVAL; |
1da177e4 LT |
4847 | |
4848 | retval = -ESRCH; | |
4849 | read_lock(&tasklist_lock); | |
4850 | p = find_process_by_pid(pid); | |
4851 | if (!p) | |
4852 | goto out_unlock; | |
4853 | ||
4854 | retval = security_task_getscheduler(p); | |
4855 | if (retval) | |
4856 | goto out_unlock; | |
4857 | ||
77034937 IM |
4858 | /* |
4859 | * Time slice is 0 for SCHED_FIFO tasks and for SCHED_OTHER | |
4860 | * tasks that are on an otherwise idle runqueue: | |
4861 | */ | |
4862 | time_slice = 0; | |
4863 | if (p->policy == SCHED_RR) { | |
a4ec24b4 | 4864 | time_slice = DEF_TIMESLICE; |
77034937 | 4865 | } else { |
a4ec24b4 DA |
4866 | struct sched_entity *se = &p->se; |
4867 | unsigned long flags; | |
4868 | struct rq *rq; | |
4869 | ||
4870 | rq = task_rq_lock(p, &flags); | |
77034937 IM |
4871 | if (rq->cfs.load.weight) |
4872 | time_slice = NS_TO_JIFFIES(sched_slice(&rq->cfs, se)); | |
a4ec24b4 DA |
4873 | task_rq_unlock(rq, &flags); |
4874 | } | |
1da177e4 | 4875 | read_unlock(&tasklist_lock); |
a4ec24b4 | 4876 | jiffies_to_timespec(time_slice, &t); |
1da177e4 | 4877 | retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0; |
1da177e4 | 4878 | return retval; |
3a5c359a | 4879 | |
1da177e4 LT |
4880 | out_unlock: |
4881 | read_unlock(&tasklist_lock); | |
4882 | return retval; | |
4883 | } | |
4884 | ||
2ed6e34f | 4885 | static const char stat_nam[] = "RSDTtZX"; |
36c8b586 IM |
4886 | |
4887 | static void show_task(struct task_struct *p) | |
1da177e4 | 4888 | { |
1da177e4 | 4889 | unsigned long free = 0; |
36c8b586 | 4890 | unsigned state; |
1da177e4 | 4891 | |
1da177e4 | 4892 | state = p->state ? __ffs(p->state) + 1 : 0; |
cc4ea795 | 4893 | printk(KERN_INFO "%-13.13s %c", p->comm, |
2ed6e34f | 4894 | state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?'); |
4bd77321 | 4895 | #if BITS_PER_LONG == 32 |
1da177e4 | 4896 | if (state == TASK_RUNNING) |
cc4ea795 | 4897 | printk(KERN_CONT " running "); |
1da177e4 | 4898 | else |
cc4ea795 | 4899 | printk(KERN_CONT " %08lx ", thread_saved_pc(p)); |
1da177e4 LT |
4900 | #else |
4901 | if (state == TASK_RUNNING) | |
cc4ea795 | 4902 | printk(KERN_CONT " running task "); |
1da177e4 | 4903 | else |
cc4ea795 | 4904 | printk(KERN_CONT " %016lx ", thread_saved_pc(p)); |
1da177e4 LT |
4905 | #endif |
4906 | #ifdef CONFIG_DEBUG_STACK_USAGE | |
4907 | { | |
10ebffde | 4908 | unsigned long *n = end_of_stack(p); |
1da177e4 LT |
4909 | while (!*n) |
4910 | n++; | |
10ebffde | 4911 | free = (unsigned long)n - (unsigned long)end_of_stack(p); |
1da177e4 LT |
4912 | } |
4913 | #endif | |
ba25f9dc PE |
4914 | printk(KERN_CONT "%5lu %5d %6d\n", free, |
4915 | task_pid_nr(p), task_pid_nr(p->parent)); | |
1da177e4 LT |
4916 | |
4917 | if (state != TASK_RUNNING) | |
4918 | show_stack(p, NULL); | |
4919 | } | |
4920 | ||
e59e2ae2 | 4921 | void show_state_filter(unsigned long state_filter) |
1da177e4 | 4922 | { |
36c8b586 | 4923 | struct task_struct *g, *p; |
1da177e4 | 4924 | |
4bd77321 IM |
4925 | #if BITS_PER_LONG == 32 |
4926 | printk(KERN_INFO | |
4927 | " task PC stack pid father\n"); | |
1da177e4 | 4928 | #else |
4bd77321 IM |
4929 | printk(KERN_INFO |
4930 | " task PC stack pid father\n"); | |
1da177e4 LT |
4931 | #endif |
4932 | read_lock(&tasklist_lock); | |
4933 | do_each_thread(g, p) { | |
4934 | /* | |
4935 | * reset the NMI-timeout, listing all files on a slow | |
4936 | * console might take alot of time: | |
4937 | */ | |
4938 | touch_nmi_watchdog(); | |
39bc89fd | 4939 | if (!state_filter || (p->state & state_filter)) |
e59e2ae2 | 4940 | show_task(p); |
1da177e4 LT |
4941 | } while_each_thread(g, p); |
4942 | ||
04c9167f JF |
4943 | touch_all_softlockup_watchdogs(); |
4944 | ||
dd41f596 IM |
4945 | #ifdef CONFIG_SCHED_DEBUG |
4946 | sysrq_sched_debug_show(); | |
4947 | #endif | |
1da177e4 | 4948 | read_unlock(&tasklist_lock); |
e59e2ae2 IM |
4949 | /* |
4950 | * Only show locks if all tasks are dumped: | |
4951 | */ | |
4952 | if (state_filter == -1) | |
4953 | debug_show_all_locks(); | |
1da177e4 LT |
4954 | } |
4955 | ||
1df21055 IM |
4956 | void __cpuinit init_idle_bootup_task(struct task_struct *idle) |
4957 | { | |
dd41f596 | 4958 | idle->sched_class = &idle_sched_class; |
1df21055 IM |
4959 | } |
4960 | ||
f340c0d1 IM |
4961 | /** |
4962 | * init_idle - set up an idle thread for a given CPU | |
4963 | * @idle: task in question | |
4964 | * @cpu: cpu the idle task belongs to | |
4965 | * | |
4966 | * NOTE: this function does not set the idle thread's NEED_RESCHED | |
4967 | * flag, to make booting more robust. | |
4968 | */ | |
5c1e1767 | 4969 | void __cpuinit init_idle(struct task_struct *idle, int cpu) |
1da177e4 | 4970 | { |
70b97a7f | 4971 | struct rq *rq = cpu_rq(cpu); |
1da177e4 LT |
4972 | unsigned long flags; |
4973 | ||
dd41f596 IM |
4974 | __sched_fork(idle); |
4975 | idle->se.exec_start = sched_clock(); | |
4976 | ||
b29739f9 | 4977 | idle->prio = idle->normal_prio = MAX_PRIO; |
1da177e4 | 4978 | idle->cpus_allowed = cpumask_of_cpu(cpu); |
dd41f596 | 4979 | __set_task_cpu(idle, cpu); |
1da177e4 LT |
4980 | |
4981 | spin_lock_irqsave(&rq->lock, flags); | |
4982 | rq->curr = rq->idle = idle; | |
4866cde0 NP |
4983 | #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW) |
4984 | idle->oncpu = 1; | |
4985 | #endif | |
1da177e4 LT |
4986 | spin_unlock_irqrestore(&rq->lock, flags); |
4987 | ||
4988 | /* Set the preempt count _outside_ the spinlocks! */ | |
4989 | #if defined(CONFIG_PREEMPT) && !defined(CONFIG_PREEMPT_BKL) | |
a1261f54 | 4990 | task_thread_info(idle)->preempt_count = (idle->lock_depth >= 0); |
1da177e4 | 4991 | #else |
a1261f54 | 4992 | task_thread_info(idle)->preempt_count = 0; |
1da177e4 | 4993 | #endif |
dd41f596 IM |
4994 | /* |
4995 | * The idle tasks have their own, simple scheduling class: | |
4996 | */ | |
4997 | idle->sched_class = &idle_sched_class; | |
1da177e4 LT |
4998 | } |
4999 | ||
5000 | /* | |
5001 | * In a system that switches off the HZ timer nohz_cpu_mask | |
5002 | * indicates which cpus entered this state. This is used | |
5003 | * in the rcu update to wait only for active cpus. For system | |
5004 | * which do not switch off the HZ timer nohz_cpu_mask should | |
5005 | * always be CPU_MASK_NONE. | |
5006 | */ | |
5007 | cpumask_t nohz_cpu_mask = CPU_MASK_NONE; | |
5008 | ||
19978ca6 IM |
5009 | /* |
5010 | * Increase the granularity value when there are more CPUs, | |
5011 | * because with more CPUs the 'effective latency' as visible | |
5012 | * to users decreases. But the relationship is not linear, | |
5013 | * so pick a second-best guess by going with the log2 of the | |
5014 | * number of CPUs. | |
5015 | * | |
5016 | * This idea comes from the SD scheduler of Con Kolivas: | |
5017 | */ | |
5018 | static inline void sched_init_granularity(void) | |
5019 | { | |
5020 | unsigned int factor = 1 + ilog2(num_online_cpus()); | |
5021 | const unsigned long limit = 200000000; | |
5022 | ||
5023 | sysctl_sched_min_granularity *= factor; | |
5024 | if (sysctl_sched_min_granularity > limit) | |
5025 | sysctl_sched_min_granularity = limit; | |
5026 | ||
5027 | sysctl_sched_latency *= factor; | |
5028 | if (sysctl_sched_latency > limit) | |
5029 | sysctl_sched_latency = limit; | |
5030 | ||
5031 | sysctl_sched_wakeup_granularity *= factor; | |
5032 | sysctl_sched_batch_wakeup_granularity *= factor; | |
5033 | } | |
5034 | ||
1da177e4 LT |
5035 | #ifdef CONFIG_SMP |
5036 | /* | |
5037 | * This is how migration works: | |
5038 | * | |
70b97a7f | 5039 | * 1) we queue a struct migration_req structure in the source CPU's |
1da177e4 LT |
5040 | * runqueue and wake up that CPU's migration thread. |
5041 | * 2) we down() the locked semaphore => thread blocks. | |
5042 | * 3) migration thread wakes up (implicitly it forces the migrated | |
5043 | * thread off the CPU) | |
5044 | * 4) it gets the migration request and checks whether the migrated | |
5045 | * task is still in the wrong runqueue. | |
5046 | * 5) if it's in the wrong runqueue then the migration thread removes | |
5047 | * it and puts it into the right queue. | |
5048 | * 6) migration thread up()s the semaphore. | |
5049 | * 7) we wake up and the migration is done. | |
5050 | */ | |
5051 | ||
5052 | /* | |
5053 | * Change a given task's CPU affinity. Migrate the thread to a | |
5054 | * proper CPU and schedule it away if the CPU it's executing on | |
5055 | * is removed from the allowed bitmask. | |
5056 | * | |
5057 | * NOTE: the caller must have a valid reference to the task, the | |
41a2d6cf | 5058 | * task must not exit() & deallocate itself prematurely. The |
1da177e4 LT |
5059 | * call is not atomic; no spinlocks may be held. |
5060 | */ | |
36c8b586 | 5061 | int set_cpus_allowed(struct task_struct *p, cpumask_t new_mask) |
1da177e4 | 5062 | { |
70b97a7f | 5063 | struct migration_req req; |
1da177e4 | 5064 | unsigned long flags; |
70b97a7f | 5065 | struct rq *rq; |
48f24c4d | 5066 | int ret = 0; |
1da177e4 LT |
5067 | |
5068 | rq = task_rq_lock(p, &flags); | |
5069 | if (!cpus_intersects(new_mask, cpu_online_map)) { | |
5070 | ret = -EINVAL; | |
5071 | goto out; | |
5072 | } | |
5073 | ||
5074 | p->cpus_allowed = new_mask; | |
5075 | /* Can the task run on the task's current CPU? If so, we're done */ | |
5076 | if (cpu_isset(task_cpu(p), new_mask)) | |
5077 | goto out; | |
5078 | ||
5079 | if (migrate_task(p, any_online_cpu(new_mask), &req)) { | |
5080 | /* Need help from migration thread: drop lock and wait. */ | |
5081 | task_rq_unlock(rq, &flags); | |
5082 | wake_up_process(rq->migration_thread); | |
5083 | wait_for_completion(&req.done); | |
5084 | tlb_migrate_finish(p->mm); | |
5085 | return 0; | |
5086 | } | |
5087 | out: | |
5088 | task_rq_unlock(rq, &flags); | |
48f24c4d | 5089 | |
1da177e4 LT |
5090 | return ret; |
5091 | } | |
1da177e4 LT |
5092 | EXPORT_SYMBOL_GPL(set_cpus_allowed); |
5093 | ||
5094 | /* | |
41a2d6cf | 5095 | * Move (not current) task off this cpu, onto dest cpu. We're doing |
1da177e4 LT |
5096 | * this because either it can't run here any more (set_cpus_allowed() |
5097 | * away from this CPU, or CPU going down), or because we're | |
5098 | * attempting to rebalance this task on exec (sched_exec). | |
5099 | * | |
5100 | * So we race with normal scheduler movements, but that's OK, as long | |
5101 | * as the task is no longer on this CPU. | |
efc30814 KK |
5102 | * |
5103 | * Returns non-zero if task was successfully migrated. | |
1da177e4 | 5104 | */ |
efc30814 | 5105 | static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu) |
1da177e4 | 5106 | { |
70b97a7f | 5107 | struct rq *rq_dest, *rq_src; |
dd41f596 | 5108 | int ret = 0, on_rq; |
1da177e4 LT |
5109 | |
5110 | if (unlikely(cpu_is_offline(dest_cpu))) | |
efc30814 | 5111 | return ret; |
1da177e4 LT |
5112 | |
5113 | rq_src = cpu_rq(src_cpu); | |
5114 | rq_dest = cpu_rq(dest_cpu); | |
5115 | ||
5116 | double_rq_lock(rq_src, rq_dest); | |
5117 | /* Already moved. */ | |
5118 | if (task_cpu(p) != src_cpu) | |
5119 | goto out; | |
5120 | /* Affinity changed (again). */ | |
5121 | if (!cpu_isset(dest_cpu, p->cpus_allowed)) | |
5122 | goto out; | |
5123 | ||
dd41f596 | 5124 | on_rq = p->se.on_rq; |
6e82a3be | 5125 | if (on_rq) |
2e1cb74a | 5126 | deactivate_task(rq_src, p, 0); |
6e82a3be | 5127 | |
1da177e4 | 5128 | set_task_cpu(p, dest_cpu); |
dd41f596 IM |
5129 | if (on_rq) { |
5130 | activate_task(rq_dest, p, 0); | |
5131 | check_preempt_curr(rq_dest, p); | |
1da177e4 | 5132 | } |
efc30814 | 5133 | ret = 1; |
1da177e4 LT |
5134 | out: |
5135 | double_rq_unlock(rq_src, rq_dest); | |
efc30814 | 5136 | return ret; |
1da177e4 LT |
5137 | } |
5138 | ||
5139 | /* | |
5140 | * migration_thread - this is a highprio system thread that performs | |
5141 | * thread migration by bumping thread off CPU then 'pushing' onto | |
5142 | * another runqueue. | |
5143 | */ | |
95cdf3b7 | 5144 | static int migration_thread(void *data) |
1da177e4 | 5145 | { |
1da177e4 | 5146 | int cpu = (long)data; |
70b97a7f | 5147 | struct rq *rq; |
1da177e4 LT |
5148 | |
5149 | rq = cpu_rq(cpu); | |
5150 | BUG_ON(rq->migration_thread != current); | |
5151 | ||
5152 | set_current_state(TASK_INTERRUPTIBLE); | |
5153 | while (!kthread_should_stop()) { | |
70b97a7f | 5154 | struct migration_req *req; |
1da177e4 | 5155 | struct list_head *head; |
1da177e4 | 5156 | |
1da177e4 LT |
5157 | spin_lock_irq(&rq->lock); |
5158 | ||
5159 | if (cpu_is_offline(cpu)) { | |
5160 | spin_unlock_irq(&rq->lock); | |
5161 | goto wait_to_die; | |
5162 | } | |
5163 | ||
5164 | if (rq->active_balance) { | |
5165 | active_load_balance(rq, cpu); | |
5166 | rq->active_balance = 0; | |
5167 | } | |
5168 | ||
5169 | head = &rq->migration_queue; | |
5170 | ||
5171 | if (list_empty(head)) { | |
5172 | spin_unlock_irq(&rq->lock); | |
5173 | schedule(); | |
5174 | set_current_state(TASK_INTERRUPTIBLE); | |
5175 | continue; | |
5176 | } | |
70b97a7f | 5177 | req = list_entry(head->next, struct migration_req, list); |
1da177e4 LT |
5178 | list_del_init(head->next); |
5179 | ||
674311d5 NP |
5180 | spin_unlock(&rq->lock); |
5181 | __migrate_task(req->task, cpu, req->dest_cpu); | |
5182 | local_irq_enable(); | |
1da177e4 LT |
5183 | |
5184 | complete(&req->done); | |
5185 | } | |
5186 | __set_current_state(TASK_RUNNING); | |
5187 | return 0; | |
5188 | ||
5189 | wait_to_die: | |
5190 | /* Wait for kthread_stop */ | |
5191 | set_current_state(TASK_INTERRUPTIBLE); | |
5192 | while (!kthread_should_stop()) { | |
5193 | schedule(); | |
5194 | set_current_state(TASK_INTERRUPTIBLE); | |
5195 | } | |
5196 | __set_current_state(TASK_RUNNING); | |
5197 | return 0; | |
5198 | } | |
5199 | ||
5200 | #ifdef CONFIG_HOTPLUG_CPU | |
f7b4cddc ON |
5201 | |
5202 | static int __migrate_task_irq(struct task_struct *p, int src_cpu, int dest_cpu) | |
5203 | { | |
5204 | int ret; | |
5205 | ||
5206 | local_irq_disable(); | |
5207 | ret = __migrate_task(p, src_cpu, dest_cpu); | |
5208 | local_irq_enable(); | |
5209 | return ret; | |
5210 | } | |
5211 | ||
054b9108 | 5212 | /* |
3a4fa0a2 | 5213 | * Figure out where task on dead CPU should go, use force if necessary. |
054b9108 KK |
5214 | * NOTE: interrupts should be disabled by the caller |
5215 | */ | |
48f24c4d | 5216 | static void move_task_off_dead_cpu(int dead_cpu, struct task_struct *p) |
1da177e4 | 5217 | { |
efc30814 | 5218 | unsigned long flags; |
1da177e4 | 5219 | cpumask_t mask; |
70b97a7f IM |
5220 | struct rq *rq; |
5221 | int dest_cpu; | |
1da177e4 | 5222 | |
3a5c359a AK |
5223 | do { |
5224 | /* On same node? */ | |
5225 | mask = node_to_cpumask(cpu_to_node(dead_cpu)); | |
5226 | cpus_and(mask, mask, p->cpus_allowed); | |
5227 | dest_cpu = any_online_cpu(mask); | |
5228 | ||
5229 | /* On any allowed CPU? */ | |
5230 | if (dest_cpu == NR_CPUS) | |
5231 | dest_cpu = any_online_cpu(p->cpus_allowed); | |
5232 | ||
5233 | /* No more Mr. Nice Guy. */ | |
5234 | if (dest_cpu == NR_CPUS) { | |
470fd646 CW |
5235 | cpumask_t cpus_allowed = cpuset_cpus_allowed_locked(p); |
5236 | /* | |
5237 | * Try to stay on the same cpuset, where the | |
5238 | * current cpuset may be a subset of all cpus. | |
5239 | * The cpuset_cpus_allowed_locked() variant of | |
41a2d6cf | 5240 | * cpuset_cpus_allowed() will not block. It must be |
470fd646 CW |
5241 | * called within calls to cpuset_lock/cpuset_unlock. |
5242 | */ | |
3a5c359a | 5243 | rq = task_rq_lock(p, &flags); |
470fd646 | 5244 | p->cpus_allowed = cpus_allowed; |
3a5c359a AK |
5245 | dest_cpu = any_online_cpu(p->cpus_allowed); |
5246 | task_rq_unlock(rq, &flags); | |
1da177e4 | 5247 | |
3a5c359a AK |
5248 | /* |
5249 | * Don't tell them about moving exiting tasks or | |
5250 | * kernel threads (both mm NULL), since they never | |
5251 | * leave kernel. | |
5252 | */ | |
41a2d6cf | 5253 | if (p->mm && printk_ratelimit()) { |
3a5c359a AK |
5254 | printk(KERN_INFO "process %d (%s) no " |
5255 | "longer affine to cpu%d\n", | |
41a2d6cf IM |
5256 | task_pid_nr(p), p->comm, dead_cpu); |
5257 | } | |
3a5c359a | 5258 | } |
f7b4cddc | 5259 | } while (!__migrate_task_irq(p, dead_cpu, dest_cpu)); |
1da177e4 LT |
5260 | } |
5261 | ||
5262 | /* | |
5263 | * While a dead CPU has no uninterruptible tasks queued at this point, | |
5264 | * it might still have a nonzero ->nr_uninterruptible counter, because | |
5265 | * for performance reasons the counter is not stricly tracking tasks to | |
5266 | * their home CPUs. So we just add the counter to another CPU's counter, | |
5267 | * to keep the global sum constant after CPU-down: | |
5268 | */ | |
70b97a7f | 5269 | static void migrate_nr_uninterruptible(struct rq *rq_src) |
1da177e4 | 5270 | { |
70b97a7f | 5271 | struct rq *rq_dest = cpu_rq(any_online_cpu(CPU_MASK_ALL)); |
1da177e4 LT |
5272 | unsigned long flags; |
5273 | ||
5274 | local_irq_save(flags); | |
5275 | double_rq_lock(rq_src, rq_dest); | |
5276 | rq_dest->nr_uninterruptible += rq_src->nr_uninterruptible; | |
5277 | rq_src->nr_uninterruptible = 0; | |
5278 | double_rq_unlock(rq_src, rq_dest); | |
5279 | local_irq_restore(flags); | |
5280 | } | |
5281 | ||
5282 | /* Run through task list and migrate tasks from the dead cpu. */ | |
5283 | static void migrate_live_tasks(int src_cpu) | |
5284 | { | |
48f24c4d | 5285 | struct task_struct *p, *t; |
1da177e4 | 5286 | |
f7b4cddc | 5287 | read_lock(&tasklist_lock); |
1da177e4 | 5288 | |
48f24c4d IM |
5289 | do_each_thread(t, p) { |
5290 | if (p == current) | |
1da177e4 LT |
5291 | continue; |
5292 | ||
48f24c4d IM |
5293 | if (task_cpu(p) == src_cpu) |
5294 | move_task_off_dead_cpu(src_cpu, p); | |
5295 | } while_each_thread(t, p); | |
1da177e4 | 5296 | |
f7b4cddc | 5297 | read_unlock(&tasklist_lock); |
1da177e4 LT |
5298 | } |
5299 | ||
dd41f596 IM |
5300 | /* |
5301 | * Schedules idle task to be the next runnable task on current CPU. | |
94bc9a7b DA |
5302 | * It does so by boosting its priority to highest possible. |
5303 | * Used by CPU offline code. | |
1da177e4 LT |
5304 | */ |
5305 | void sched_idle_next(void) | |
5306 | { | |
48f24c4d | 5307 | int this_cpu = smp_processor_id(); |
70b97a7f | 5308 | struct rq *rq = cpu_rq(this_cpu); |
1da177e4 LT |
5309 | struct task_struct *p = rq->idle; |
5310 | unsigned long flags; | |
5311 | ||
5312 | /* cpu has to be offline */ | |
48f24c4d | 5313 | BUG_ON(cpu_online(this_cpu)); |
1da177e4 | 5314 | |
48f24c4d IM |
5315 | /* |
5316 | * Strictly not necessary since rest of the CPUs are stopped by now | |
5317 | * and interrupts disabled on the current cpu. | |
1da177e4 LT |
5318 | */ |
5319 | spin_lock_irqsave(&rq->lock, flags); | |
5320 | ||
dd41f596 | 5321 | __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1); |
48f24c4d | 5322 | |
94bc9a7b DA |
5323 | update_rq_clock(rq); |
5324 | activate_task(rq, p, 0); | |
1da177e4 LT |
5325 | |
5326 | spin_unlock_irqrestore(&rq->lock, flags); | |
5327 | } | |
5328 | ||
48f24c4d IM |
5329 | /* |
5330 | * Ensures that the idle task is using init_mm right before its cpu goes | |
1da177e4 LT |
5331 | * offline. |
5332 | */ | |
5333 | void idle_task_exit(void) | |
5334 | { | |
5335 | struct mm_struct *mm = current->active_mm; | |
5336 | ||
5337 | BUG_ON(cpu_online(smp_processor_id())); | |
5338 | ||
5339 | if (mm != &init_mm) | |
5340 | switch_mm(mm, &init_mm, current); | |
5341 | mmdrop(mm); | |
5342 | } | |
5343 | ||
054b9108 | 5344 | /* called under rq->lock with disabled interrupts */ |
36c8b586 | 5345 | static void migrate_dead(unsigned int dead_cpu, struct task_struct *p) |
1da177e4 | 5346 | { |
70b97a7f | 5347 | struct rq *rq = cpu_rq(dead_cpu); |
1da177e4 LT |
5348 | |
5349 | /* Must be exiting, otherwise would be on tasklist. */ | |
270f722d | 5350 | BUG_ON(!p->exit_state); |
1da177e4 LT |
5351 | |
5352 | /* Cannot have done final schedule yet: would have vanished. */ | |
c394cc9f | 5353 | BUG_ON(p->state == TASK_DEAD); |
1da177e4 | 5354 | |
48f24c4d | 5355 | get_task_struct(p); |
1da177e4 LT |
5356 | |
5357 | /* | |
5358 | * Drop lock around migration; if someone else moves it, | |
41a2d6cf | 5359 | * that's OK. No task can be added to this CPU, so iteration is |
1da177e4 LT |
5360 | * fine. |
5361 | */ | |
f7b4cddc | 5362 | spin_unlock_irq(&rq->lock); |
48f24c4d | 5363 | move_task_off_dead_cpu(dead_cpu, p); |
f7b4cddc | 5364 | spin_lock_irq(&rq->lock); |
1da177e4 | 5365 | |
48f24c4d | 5366 | put_task_struct(p); |
1da177e4 LT |
5367 | } |
5368 | ||
5369 | /* release_task() removes task from tasklist, so we won't find dead tasks. */ | |
5370 | static void migrate_dead_tasks(unsigned int dead_cpu) | |
5371 | { | |
70b97a7f | 5372 | struct rq *rq = cpu_rq(dead_cpu); |
dd41f596 | 5373 | struct task_struct *next; |
48f24c4d | 5374 | |
dd41f596 IM |
5375 | for ( ; ; ) { |
5376 | if (!rq->nr_running) | |
5377 | break; | |
a8e504d2 | 5378 | update_rq_clock(rq); |
ff95f3df | 5379 | next = pick_next_task(rq, rq->curr); |
dd41f596 IM |
5380 | if (!next) |
5381 | break; | |
5382 | migrate_dead(dead_cpu, next); | |
e692ab53 | 5383 | |
1da177e4 LT |
5384 | } |
5385 | } | |
5386 | #endif /* CONFIG_HOTPLUG_CPU */ | |
5387 | ||
e692ab53 NP |
5388 | #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL) |
5389 | ||
5390 | static struct ctl_table sd_ctl_dir[] = { | |
e0361851 AD |
5391 | { |
5392 | .procname = "sched_domain", | |
c57baf1e | 5393 | .mode = 0555, |
e0361851 | 5394 | }, |
38605cae | 5395 | {0, }, |
e692ab53 NP |
5396 | }; |
5397 | ||
5398 | static struct ctl_table sd_ctl_root[] = { | |
e0361851 | 5399 | { |
c57baf1e | 5400 | .ctl_name = CTL_KERN, |
e0361851 | 5401 | .procname = "kernel", |
c57baf1e | 5402 | .mode = 0555, |
e0361851 AD |
5403 | .child = sd_ctl_dir, |
5404 | }, | |
38605cae | 5405 | {0, }, |
e692ab53 NP |
5406 | }; |
5407 | ||
5408 | static struct ctl_table *sd_alloc_ctl_entry(int n) | |
5409 | { | |
5410 | struct ctl_table *entry = | |
5cf9f062 | 5411 | kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL); |
e692ab53 | 5412 | |
e692ab53 NP |
5413 | return entry; |
5414 | } | |
5415 | ||
6382bc90 MM |
5416 | static void sd_free_ctl_entry(struct ctl_table **tablep) |
5417 | { | |
cd790076 | 5418 | struct ctl_table *entry; |
6382bc90 | 5419 | |
cd790076 MM |
5420 | /* |
5421 | * In the intermediate directories, both the child directory and | |
5422 | * procname are dynamically allocated and could fail but the mode | |
41a2d6cf | 5423 | * will always be set. In the lowest directory the names are |
cd790076 MM |
5424 | * static strings and all have proc handlers. |
5425 | */ | |
5426 | for (entry = *tablep; entry->mode; entry++) { | |
6382bc90 MM |
5427 | if (entry->child) |
5428 | sd_free_ctl_entry(&entry->child); | |
cd790076 MM |
5429 | if (entry->proc_handler == NULL) |
5430 | kfree(entry->procname); | |
5431 | } | |
6382bc90 MM |
5432 | |
5433 | kfree(*tablep); | |
5434 | *tablep = NULL; | |
5435 | } | |
5436 | ||
e692ab53 | 5437 | static void |
e0361851 | 5438 | set_table_entry(struct ctl_table *entry, |
e692ab53 NP |
5439 | const char *procname, void *data, int maxlen, |
5440 | mode_t mode, proc_handler *proc_handler) | |
5441 | { | |
e692ab53 NP |
5442 | entry->procname = procname; |
5443 | entry->data = data; | |
5444 | entry->maxlen = maxlen; | |
5445 | entry->mode = mode; | |
5446 | entry->proc_handler = proc_handler; | |
5447 | } | |
5448 | ||
5449 | static struct ctl_table * | |
5450 | sd_alloc_ctl_domain_table(struct sched_domain *sd) | |
5451 | { | |
ace8b3d6 | 5452 | struct ctl_table *table = sd_alloc_ctl_entry(12); |
e692ab53 | 5453 | |
ad1cdc1d MM |
5454 | if (table == NULL) |
5455 | return NULL; | |
5456 | ||
e0361851 | 5457 | set_table_entry(&table[0], "min_interval", &sd->min_interval, |
e692ab53 | 5458 | sizeof(long), 0644, proc_doulongvec_minmax); |
e0361851 | 5459 | set_table_entry(&table[1], "max_interval", &sd->max_interval, |
e692ab53 | 5460 | sizeof(long), 0644, proc_doulongvec_minmax); |
e0361851 | 5461 | set_table_entry(&table[2], "busy_idx", &sd->busy_idx, |
e692ab53 | 5462 | sizeof(int), 0644, proc_dointvec_minmax); |
e0361851 | 5463 | set_table_entry(&table[3], "idle_idx", &sd->idle_idx, |
e692ab53 | 5464 | sizeof(int), 0644, proc_dointvec_minmax); |
e0361851 | 5465 | set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx, |
e692ab53 | 5466 | sizeof(int), 0644, proc_dointvec_minmax); |
e0361851 | 5467 | set_table_entry(&table[5], "wake_idx", &sd->wake_idx, |
e692ab53 | 5468 | sizeof(int), 0644, proc_dointvec_minmax); |
e0361851 | 5469 | set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx, |
e692ab53 | 5470 | sizeof(int), 0644, proc_dointvec_minmax); |
e0361851 | 5471 | set_table_entry(&table[7], "busy_factor", &sd->busy_factor, |
e692ab53 | 5472 | sizeof(int), 0644, proc_dointvec_minmax); |
e0361851 | 5473 | set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct, |
e692ab53 | 5474 | sizeof(int), 0644, proc_dointvec_minmax); |
ace8b3d6 | 5475 | set_table_entry(&table[9], "cache_nice_tries", |
e692ab53 NP |
5476 | &sd->cache_nice_tries, |
5477 | sizeof(int), 0644, proc_dointvec_minmax); | |
ace8b3d6 | 5478 | set_table_entry(&table[10], "flags", &sd->flags, |
e692ab53 | 5479 | sizeof(int), 0644, proc_dointvec_minmax); |
6323469f | 5480 | /* &table[11] is terminator */ |
e692ab53 NP |
5481 | |
5482 | return table; | |
5483 | } | |
5484 | ||
9a4e7159 | 5485 | static ctl_table *sd_alloc_ctl_cpu_table(int cpu) |
e692ab53 NP |
5486 | { |
5487 | struct ctl_table *entry, *table; | |
5488 | struct sched_domain *sd; | |
5489 | int domain_num = 0, i; | |
5490 | char buf[32]; | |
5491 | ||
5492 | for_each_domain(cpu, sd) | |
5493 | domain_num++; | |
5494 | entry = table = sd_alloc_ctl_entry(domain_num + 1); | |
ad1cdc1d MM |
5495 | if (table == NULL) |
5496 | return NULL; | |
e692ab53 NP |
5497 | |
5498 | i = 0; | |
5499 | for_each_domain(cpu, sd) { | |
5500 | snprintf(buf, 32, "domain%d", i); | |
e692ab53 | 5501 | entry->procname = kstrdup(buf, GFP_KERNEL); |
c57baf1e | 5502 | entry->mode = 0555; |
e692ab53 NP |
5503 | entry->child = sd_alloc_ctl_domain_table(sd); |
5504 | entry++; | |
5505 | i++; | |
5506 | } | |
5507 | return table; | |
5508 | } | |
5509 | ||
5510 | static struct ctl_table_header *sd_sysctl_header; | |
6382bc90 | 5511 | static void register_sched_domain_sysctl(void) |
e692ab53 NP |
5512 | { |
5513 | int i, cpu_num = num_online_cpus(); | |
5514 | struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1); | |
5515 | char buf[32]; | |
5516 | ||
7378547f MM |
5517 | WARN_ON(sd_ctl_dir[0].child); |
5518 | sd_ctl_dir[0].child = entry; | |
5519 | ||
ad1cdc1d MM |
5520 | if (entry == NULL) |
5521 | return; | |
5522 | ||
97b6ea7b | 5523 | for_each_online_cpu(i) { |
e692ab53 | 5524 | snprintf(buf, 32, "cpu%d", i); |
e692ab53 | 5525 | entry->procname = kstrdup(buf, GFP_KERNEL); |
c57baf1e | 5526 | entry->mode = 0555; |
e692ab53 | 5527 | entry->child = sd_alloc_ctl_cpu_table(i); |
97b6ea7b | 5528 | entry++; |
e692ab53 | 5529 | } |
7378547f MM |
5530 | |
5531 | WARN_ON(sd_sysctl_header); | |
e692ab53 NP |
5532 | sd_sysctl_header = register_sysctl_table(sd_ctl_root); |
5533 | } | |
6382bc90 | 5534 | |
7378547f | 5535 | /* may be called multiple times per register */ |
6382bc90 MM |
5536 | static void unregister_sched_domain_sysctl(void) |
5537 | { | |
7378547f MM |
5538 | if (sd_sysctl_header) |
5539 | unregister_sysctl_table(sd_sysctl_header); | |
6382bc90 | 5540 | sd_sysctl_header = NULL; |
7378547f MM |
5541 | if (sd_ctl_dir[0].child) |
5542 | sd_free_ctl_entry(&sd_ctl_dir[0].child); | |
6382bc90 | 5543 | } |
e692ab53 | 5544 | #else |
6382bc90 MM |
5545 | static void register_sched_domain_sysctl(void) |
5546 | { | |
5547 | } | |
5548 | static void unregister_sched_domain_sysctl(void) | |
e692ab53 NP |
5549 | { |
5550 | } | |
5551 | #endif | |
5552 | ||
1da177e4 LT |
5553 | /* |
5554 | * migration_call - callback that gets triggered when a CPU is added. | |
5555 | * Here we can start up the necessary migration thread for the new CPU. | |
5556 | */ | |
48f24c4d IM |
5557 | static int __cpuinit |
5558 | migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) | |
1da177e4 | 5559 | { |
1da177e4 | 5560 | struct task_struct *p; |
48f24c4d | 5561 | int cpu = (long)hcpu; |
1da177e4 | 5562 | unsigned long flags; |
70b97a7f | 5563 | struct rq *rq; |
1da177e4 LT |
5564 | |
5565 | switch (action) { | |
5be9361c GS |
5566 | case CPU_LOCK_ACQUIRE: |
5567 | mutex_lock(&sched_hotcpu_mutex); | |
5568 | break; | |
5569 | ||
1da177e4 | 5570 | case CPU_UP_PREPARE: |
8bb78442 | 5571 | case CPU_UP_PREPARE_FROZEN: |
dd41f596 | 5572 | p = kthread_create(migration_thread, hcpu, "migration/%d", cpu); |
1da177e4 LT |
5573 | if (IS_ERR(p)) |
5574 | return NOTIFY_BAD; | |
1da177e4 LT |
5575 | kthread_bind(p, cpu); |
5576 | /* Must be high prio: stop_machine expects to yield to it. */ | |
5577 | rq = task_rq_lock(p, &flags); | |
dd41f596 | 5578 | __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1); |
1da177e4 LT |
5579 | task_rq_unlock(rq, &flags); |
5580 | cpu_rq(cpu)->migration_thread = p; | |
5581 | break; | |
48f24c4d | 5582 | |
1da177e4 | 5583 | case CPU_ONLINE: |
8bb78442 | 5584 | case CPU_ONLINE_FROZEN: |
3a4fa0a2 | 5585 | /* Strictly unnecessary, as first user will wake it. */ |
1da177e4 LT |
5586 | wake_up_process(cpu_rq(cpu)->migration_thread); |
5587 | break; | |
48f24c4d | 5588 | |
1da177e4 LT |
5589 | #ifdef CONFIG_HOTPLUG_CPU |
5590 | case CPU_UP_CANCELED: | |
8bb78442 | 5591 | case CPU_UP_CANCELED_FROZEN: |
fc75cdfa HC |
5592 | if (!cpu_rq(cpu)->migration_thread) |
5593 | break; | |
41a2d6cf | 5594 | /* Unbind it from offline cpu so it can run. Fall thru. */ |
a4c4af7c HC |
5595 | kthread_bind(cpu_rq(cpu)->migration_thread, |
5596 | any_online_cpu(cpu_online_map)); | |
1da177e4 LT |
5597 | kthread_stop(cpu_rq(cpu)->migration_thread); |
5598 | cpu_rq(cpu)->migration_thread = NULL; | |
5599 | break; | |
48f24c4d | 5600 | |
1da177e4 | 5601 | case CPU_DEAD: |
8bb78442 | 5602 | case CPU_DEAD_FROZEN: |
470fd646 | 5603 | cpuset_lock(); /* around calls to cpuset_cpus_allowed_lock() */ |
1da177e4 LT |
5604 | migrate_live_tasks(cpu); |
5605 | rq = cpu_rq(cpu); | |
5606 | kthread_stop(rq->migration_thread); | |
5607 | rq->migration_thread = NULL; | |
5608 | /* Idle task back to normal (off runqueue, low prio) */ | |
d2da272a | 5609 | spin_lock_irq(&rq->lock); |
a8e504d2 | 5610 | update_rq_clock(rq); |
2e1cb74a | 5611 | deactivate_task(rq, rq->idle, 0); |
1da177e4 | 5612 | rq->idle->static_prio = MAX_PRIO; |
dd41f596 IM |
5613 | __setscheduler(rq, rq->idle, SCHED_NORMAL, 0); |
5614 | rq->idle->sched_class = &idle_sched_class; | |
1da177e4 | 5615 | migrate_dead_tasks(cpu); |
d2da272a | 5616 | spin_unlock_irq(&rq->lock); |
470fd646 | 5617 | cpuset_unlock(); |
1da177e4 LT |
5618 | migrate_nr_uninterruptible(rq); |
5619 | BUG_ON(rq->nr_running != 0); | |
5620 | ||
41a2d6cf IM |
5621 | /* |
5622 | * No need to migrate the tasks: it was best-effort if | |
5623 | * they didn't take sched_hotcpu_mutex. Just wake up | |
5624 | * the requestors. | |
5625 | */ | |
1da177e4 LT |
5626 | spin_lock_irq(&rq->lock); |
5627 | while (!list_empty(&rq->migration_queue)) { | |
70b97a7f IM |
5628 | struct migration_req *req; |
5629 | ||
1da177e4 | 5630 | req = list_entry(rq->migration_queue.next, |
70b97a7f | 5631 | struct migration_req, list); |
1da177e4 LT |
5632 | list_del_init(&req->list); |
5633 | complete(&req->done); | |
5634 | } | |
5635 | spin_unlock_irq(&rq->lock); | |
5636 | break; | |
5637 | #endif | |
5be9361c GS |
5638 | case CPU_LOCK_RELEASE: |
5639 | mutex_unlock(&sched_hotcpu_mutex); | |
5640 | break; | |
1da177e4 LT |
5641 | } |
5642 | return NOTIFY_OK; | |
5643 | } | |
5644 | ||
5645 | /* Register at highest priority so that task migration (migrate_all_tasks) | |
5646 | * happens before everything else. | |
5647 | */ | |
26c2143b | 5648 | static struct notifier_block __cpuinitdata migration_notifier = { |
1da177e4 LT |
5649 | .notifier_call = migration_call, |
5650 | .priority = 10 | |
5651 | }; | |
5652 | ||
e6fe6649 | 5653 | void __init migration_init(void) |
1da177e4 LT |
5654 | { |
5655 | void *cpu = (void *)(long)smp_processor_id(); | |
07dccf33 | 5656 | int err; |
48f24c4d IM |
5657 | |
5658 | /* Start one for the boot CPU: */ | |
07dccf33 AM |
5659 | err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu); |
5660 | BUG_ON(err == NOTIFY_BAD); | |
1da177e4 LT |
5661 | migration_call(&migration_notifier, CPU_ONLINE, cpu); |
5662 | register_cpu_notifier(&migration_notifier); | |
1da177e4 LT |
5663 | } |
5664 | #endif | |
5665 | ||
5666 | #ifdef CONFIG_SMP | |
476f3534 CL |
5667 | |
5668 | /* Number of possible processor ids */ | |
5669 | int nr_cpu_ids __read_mostly = NR_CPUS; | |
5670 | EXPORT_SYMBOL(nr_cpu_ids); | |
5671 | ||
3e9830dc | 5672 | #ifdef CONFIG_SCHED_DEBUG |
4dcf6aff IM |
5673 | |
5674 | static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level) | |
1da177e4 | 5675 | { |
4dcf6aff IM |
5676 | struct sched_group *group = sd->groups; |
5677 | cpumask_t groupmask; | |
5678 | char str[NR_CPUS]; | |
1da177e4 | 5679 | |
4dcf6aff IM |
5680 | cpumask_scnprintf(str, NR_CPUS, sd->span); |
5681 | cpus_clear(groupmask); | |
5682 | ||
5683 | printk(KERN_DEBUG "%*s domain %d: ", level, "", level); | |
5684 | ||
5685 | if (!(sd->flags & SD_LOAD_BALANCE)) { | |
5686 | printk("does not load-balance\n"); | |
5687 | if (sd->parent) | |
5688 | printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain" | |
5689 | " has parent"); | |
5690 | return -1; | |
41c7ce9a NP |
5691 | } |
5692 | ||
4dcf6aff IM |
5693 | printk(KERN_CONT "span %s\n", str); |
5694 | ||
5695 | if (!cpu_isset(cpu, sd->span)) { | |
5696 | printk(KERN_ERR "ERROR: domain->span does not contain " | |
5697 | "CPU%d\n", cpu); | |
5698 | } | |
5699 | if (!cpu_isset(cpu, group->cpumask)) { | |
5700 | printk(KERN_ERR "ERROR: domain->groups does not contain" | |
5701 | " CPU%d\n", cpu); | |
5702 | } | |
1da177e4 | 5703 | |
4dcf6aff | 5704 | printk(KERN_DEBUG "%*s groups:", level + 1, ""); |
1da177e4 | 5705 | do { |
4dcf6aff IM |
5706 | if (!group) { |
5707 | printk("\n"); | |
5708 | printk(KERN_ERR "ERROR: group is NULL\n"); | |
1da177e4 LT |
5709 | break; |
5710 | } | |
5711 | ||
4dcf6aff IM |
5712 | if (!group->__cpu_power) { |
5713 | printk(KERN_CONT "\n"); | |
5714 | printk(KERN_ERR "ERROR: domain->cpu_power not " | |
5715 | "set\n"); | |
5716 | break; | |
5717 | } | |
1da177e4 | 5718 | |
4dcf6aff IM |
5719 | if (!cpus_weight(group->cpumask)) { |
5720 | printk(KERN_CONT "\n"); | |
5721 | printk(KERN_ERR "ERROR: empty group\n"); | |
5722 | break; | |
5723 | } | |
1da177e4 | 5724 | |
4dcf6aff IM |
5725 | if (cpus_intersects(groupmask, group->cpumask)) { |
5726 | printk(KERN_CONT "\n"); | |
5727 | printk(KERN_ERR "ERROR: repeated CPUs\n"); | |
5728 | break; | |
5729 | } | |
1da177e4 | 5730 | |
4dcf6aff | 5731 | cpus_or(groupmask, groupmask, group->cpumask); |
1da177e4 | 5732 | |
4dcf6aff IM |
5733 | cpumask_scnprintf(str, NR_CPUS, group->cpumask); |
5734 | printk(KERN_CONT " %s", str); | |
1da177e4 | 5735 | |
4dcf6aff IM |
5736 | group = group->next; |
5737 | } while (group != sd->groups); | |
5738 | printk(KERN_CONT "\n"); | |
1da177e4 | 5739 | |
4dcf6aff IM |
5740 | if (!cpus_equal(sd->span, groupmask)) |
5741 | printk(KERN_ERR "ERROR: groups don't span domain->span\n"); | |
1da177e4 | 5742 | |
4dcf6aff IM |
5743 | if (sd->parent && !cpus_subset(groupmask, sd->parent->span)) |
5744 | printk(KERN_ERR "ERROR: parent span is not a superset " | |
5745 | "of domain->span\n"); | |
5746 | return 0; | |
5747 | } | |
1da177e4 | 5748 | |
4dcf6aff IM |
5749 | static void sched_domain_debug(struct sched_domain *sd, int cpu) |
5750 | { | |
5751 | int level = 0; | |
1da177e4 | 5752 | |
4dcf6aff IM |
5753 | if (!sd) { |
5754 | printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu); | |
5755 | return; | |
5756 | } | |
1da177e4 | 5757 | |
4dcf6aff IM |
5758 | printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu); |
5759 | ||
5760 | for (;;) { | |
5761 | if (sched_domain_debug_one(sd, cpu, level)) | |
5762 | break; | |
1da177e4 LT |
5763 | level++; |
5764 | sd = sd->parent; | |
33859f7f | 5765 | if (!sd) |
4dcf6aff IM |
5766 | break; |
5767 | } | |
1da177e4 LT |
5768 | } |
5769 | #else | |
48f24c4d | 5770 | # define sched_domain_debug(sd, cpu) do { } while (0) |
1da177e4 LT |
5771 | #endif |
5772 | ||
1a20ff27 | 5773 | static int sd_degenerate(struct sched_domain *sd) |
245af2c7 SS |
5774 | { |
5775 | if (cpus_weight(sd->span) == 1) | |
5776 | return 1; | |
5777 | ||
5778 | /* Following flags need at least 2 groups */ | |
5779 | if (sd->flags & (SD_LOAD_BALANCE | | |
5780 | SD_BALANCE_NEWIDLE | | |
5781 | SD_BALANCE_FORK | | |
89c4710e SS |
5782 | SD_BALANCE_EXEC | |
5783 | SD_SHARE_CPUPOWER | | |
5784 | SD_SHARE_PKG_RESOURCES)) { | |
245af2c7 SS |
5785 | if (sd->groups != sd->groups->next) |
5786 | return 0; | |
5787 | } | |
5788 | ||
5789 | /* Following flags don't use groups */ | |
5790 | if (sd->flags & (SD_WAKE_IDLE | | |
5791 | SD_WAKE_AFFINE | | |
5792 | SD_WAKE_BALANCE)) | |
5793 | return 0; | |
5794 | ||
5795 | return 1; | |
5796 | } | |
5797 | ||
48f24c4d IM |
5798 | static int |
5799 | sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent) | |
245af2c7 SS |
5800 | { |
5801 | unsigned long cflags = sd->flags, pflags = parent->flags; | |
5802 | ||
5803 | if (sd_degenerate(parent)) | |
5804 | return 1; | |
5805 | ||
5806 | if (!cpus_equal(sd->span, parent->span)) | |
5807 | return 0; | |
5808 | ||
5809 | /* Does parent contain flags not in child? */ | |
5810 | /* WAKE_BALANCE is a subset of WAKE_AFFINE */ | |
5811 | if (cflags & SD_WAKE_AFFINE) | |
5812 | pflags &= ~SD_WAKE_BALANCE; | |
5813 | /* Flags needing groups don't count if only 1 group in parent */ | |
5814 | if (parent->groups == parent->groups->next) { | |
5815 | pflags &= ~(SD_LOAD_BALANCE | | |
5816 | SD_BALANCE_NEWIDLE | | |
5817 | SD_BALANCE_FORK | | |
89c4710e SS |
5818 | SD_BALANCE_EXEC | |
5819 | SD_SHARE_CPUPOWER | | |
5820 | SD_SHARE_PKG_RESOURCES); | |
245af2c7 SS |
5821 | } |
5822 | if (~cflags & pflags) | |
5823 | return 0; | |
5824 | ||
5825 | return 1; | |
5826 | } | |
5827 | ||
1da177e4 LT |
5828 | /* |
5829 | * Attach the domain 'sd' to 'cpu' as its base domain. Callers must | |
5830 | * hold the hotplug lock. | |
5831 | */ | |
9c1cfda2 | 5832 | static void cpu_attach_domain(struct sched_domain *sd, int cpu) |
1da177e4 | 5833 | { |
70b97a7f | 5834 | struct rq *rq = cpu_rq(cpu); |
245af2c7 SS |
5835 | struct sched_domain *tmp; |
5836 | ||
5837 | /* Remove the sched domains which do not contribute to scheduling. */ | |
5838 | for (tmp = sd; tmp; tmp = tmp->parent) { | |
5839 | struct sched_domain *parent = tmp->parent; | |
5840 | if (!parent) | |
5841 | break; | |
1a848870 | 5842 | if (sd_parent_degenerate(tmp, parent)) { |
245af2c7 | 5843 | tmp->parent = parent->parent; |
1a848870 SS |
5844 | if (parent->parent) |
5845 | parent->parent->child = tmp; | |
5846 | } | |
245af2c7 SS |
5847 | } |
5848 | ||
1a848870 | 5849 | if (sd && sd_degenerate(sd)) { |
245af2c7 | 5850 | sd = sd->parent; |
1a848870 SS |
5851 | if (sd) |
5852 | sd->child = NULL; | |
5853 | } | |
1da177e4 LT |
5854 | |
5855 | sched_domain_debug(sd, cpu); | |
5856 | ||
674311d5 | 5857 | rcu_assign_pointer(rq->sd, sd); |
1da177e4 LT |
5858 | } |
5859 | ||
5860 | /* cpus with isolated domains */ | |
67af63a6 | 5861 | static cpumask_t cpu_isolated_map = CPU_MASK_NONE; |
1da177e4 LT |
5862 | |
5863 | /* Setup the mask of cpus configured for isolated domains */ | |
5864 | static int __init isolated_cpu_setup(char *str) | |
5865 | { | |
5866 | int ints[NR_CPUS], i; | |
5867 | ||
5868 | str = get_options(str, ARRAY_SIZE(ints), ints); | |
5869 | cpus_clear(cpu_isolated_map); | |
5870 | for (i = 1; i <= ints[0]; i++) | |
5871 | if (ints[i] < NR_CPUS) | |
5872 | cpu_set(ints[i], cpu_isolated_map); | |
5873 | return 1; | |
5874 | } | |
5875 | ||
8927f494 | 5876 | __setup("isolcpus=", isolated_cpu_setup); |
1da177e4 LT |
5877 | |
5878 | /* | |
6711cab4 SS |
5879 | * init_sched_build_groups takes the cpumask we wish to span, and a pointer |
5880 | * to a function which identifies what group(along with sched group) a CPU | |
5881 | * belongs to. The return value of group_fn must be a >= 0 and < NR_CPUS | |
5882 | * (due to the fact that we keep track of groups covered with a cpumask_t). | |
1da177e4 LT |
5883 | * |
5884 | * init_sched_build_groups will build a circular linked list of the groups | |
5885 | * covered by the given span, and will set each group's ->cpumask correctly, | |
5886 | * and ->cpu_power to 0. | |
5887 | */ | |
a616058b | 5888 | static void |
6711cab4 SS |
5889 | init_sched_build_groups(cpumask_t span, const cpumask_t *cpu_map, |
5890 | int (*group_fn)(int cpu, const cpumask_t *cpu_map, | |
5891 | struct sched_group **sg)) | |
1da177e4 LT |
5892 | { |
5893 | struct sched_group *first = NULL, *last = NULL; | |
5894 | cpumask_t covered = CPU_MASK_NONE; | |
5895 | int i; | |
5896 | ||
5897 | for_each_cpu_mask(i, span) { | |
6711cab4 SS |
5898 | struct sched_group *sg; |
5899 | int group = group_fn(i, cpu_map, &sg); | |
1da177e4 LT |
5900 | int j; |
5901 | ||
5902 | if (cpu_isset(i, covered)) | |
5903 | continue; | |
5904 | ||
5905 | sg->cpumask = CPU_MASK_NONE; | |
5517d86b | 5906 | sg->__cpu_power = 0; |
1da177e4 LT |
5907 | |
5908 | for_each_cpu_mask(j, span) { | |
6711cab4 | 5909 | if (group_fn(j, cpu_map, NULL) != group) |
1da177e4 LT |
5910 | continue; |
5911 | ||
5912 | cpu_set(j, covered); | |
5913 | cpu_set(j, sg->cpumask); | |
5914 | } | |
5915 | if (!first) | |
5916 | first = sg; | |
5917 | if (last) | |
5918 | last->next = sg; | |
5919 | last = sg; | |
5920 | } | |
5921 | last->next = first; | |
5922 | } | |
5923 | ||
9c1cfda2 | 5924 | #define SD_NODES_PER_DOMAIN 16 |
1da177e4 | 5925 | |
9c1cfda2 | 5926 | #ifdef CONFIG_NUMA |
198e2f18 | 5927 | |
9c1cfda2 JH |
5928 | /** |
5929 | * find_next_best_node - find the next node to include in a sched_domain | |
5930 | * @node: node whose sched_domain we're building | |
5931 | * @used_nodes: nodes already in the sched_domain | |
5932 | * | |
41a2d6cf | 5933 | * Find the next node to include in a given scheduling domain. Simply |
9c1cfda2 JH |
5934 | * finds the closest node not already in the @used_nodes map. |
5935 | * | |
5936 | * Should use nodemask_t. | |
5937 | */ | |
5938 | static int find_next_best_node(int node, unsigned long *used_nodes) | |
5939 | { | |
5940 | int i, n, val, min_val, best_node = 0; | |
5941 | ||
5942 | min_val = INT_MAX; | |
5943 | ||
5944 | for (i = 0; i < MAX_NUMNODES; i++) { | |
5945 | /* Start at @node */ | |
5946 | n = (node + i) % MAX_NUMNODES; | |
5947 | ||
5948 | if (!nr_cpus_node(n)) | |
5949 | continue; | |
5950 | ||
5951 | /* Skip already used nodes */ | |
5952 | if (test_bit(n, used_nodes)) | |
5953 | continue; | |
5954 | ||
5955 | /* Simple min distance search */ | |
5956 | val = node_distance(node, n); | |
5957 | ||
5958 | if (val < min_val) { | |
5959 | min_val = val; | |
5960 | best_node = n; | |
5961 | } | |
5962 | } | |
5963 | ||
5964 | set_bit(best_node, used_nodes); | |
5965 | return best_node; | |
5966 | } | |
5967 | ||
5968 | /** | |
5969 | * sched_domain_node_span - get a cpumask for a node's sched_domain | |
5970 | * @node: node whose cpumask we're constructing | |
5971 | * @size: number of nodes to include in this span | |
5972 | * | |
41a2d6cf | 5973 | * Given a node, construct a good cpumask for its sched_domain to span. It |
9c1cfda2 JH |
5974 | * should be one that prevents unnecessary balancing, but also spreads tasks |
5975 | * out optimally. | |
5976 | */ | |
5977 | static cpumask_t sched_domain_node_span(int node) | |
5978 | { | |
9c1cfda2 | 5979 | DECLARE_BITMAP(used_nodes, MAX_NUMNODES); |
48f24c4d IM |
5980 | cpumask_t span, nodemask; |
5981 | int i; | |
9c1cfda2 JH |
5982 | |
5983 | cpus_clear(span); | |
5984 | bitmap_zero(used_nodes, MAX_NUMNODES); | |
5985 | ||
5986 | nodemask = node_to_cpumask(node); | |
5987 | cpus_or(span, span, nodemask); | |
5988 | set_bit(node, used_nodes); | |
5989 | ||
5990 | for (i = 1; i < SD_NODES_PER_DOMAIN; i++) { | |
5991 | int next_node = find_next_best_node(node, used_nodes); | |
48f24c4d | 5992 | |
9c1cfda2 JH |
5993 | nodemask = node_to_cpumask(next_node); |
5994 | cpus_or(span, span, nodemask); | |
5995 | } | |
5996 | ||
5997 | return span; | |
5998 | } | |
5999 | #endif | |
6000 | ||
5c45bf27 | 6001 | int sched_smt_power_savings = 0, sched_mc_power_savings = 0; |
48f24c4d | 6002 | |
9c1cfda2 | 6003 | /* |
48f24c4d | 6004 | * SMT sched-domains: |
9c1cfda2 | 6005 | */ |
1da177e4 LT |
6006 | #ifdef CONFIG_SCHED_SMT |
6007 | static DEFINE_PER_CPU(struct sched_domain, cpu_domains); | |
6711cab4 | 6008 | static DEFINE_PER_CPU(struct sched_group, sched_group_cpus); |
48f24c4d | 6009 | |
41a2d6cf IM |
6010 | static int |
6011 | cpu_to_cpu_group(int cpu, const cpumask_t *cpu_map, struct sched_group **sg) | |
1da177e4 | 6012 | { |
6711cab4 SS |
6013 | if (sg) |
6014 | *sg = &per_cpu(sched_group_cpus, cpu); | |
1da177e4 LT |
6015 | return cpu; |
6016 | } | |
6017 | #endif | |
6018 | ||
48f24c4d IM |
6019 | /* |
6020 | * multi-core sched-domains: | |
6021 | */ | |
1e9f28fa SS |
6022 | #ifdef CONFIG_SCHED_MC |
6023 | static DEFINE_PER_CPU(struct sched_domain, core_domains); | |
6711cab4 | 6024 | static DEFINE_PER_CPU(struct sched_group, sched_group_core); |
1e9f28fa SS |
6025 | #endif |
6026 | ||
6027 | #if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT) | |
41a2d6cf IM |
6028 | static int |
6029 | cpu_to_core_group(int cpu, const cpumask_t *cpu_map, struct sched_group **sg) | |
1e9f28fa | 6030 | { |
6711cab4 | 6031 | int group; |
d5a7430d | 6032 | cpumask_t mask = per_cpu(cpu_sibling_map, cpu); |
a616058b | 6033 | cpus_and(mask, mask, *cpu_map); |
6711cab4 SS |
6034 | group = first_cpu(mask); |
6035 | if (sg) | |
6036 | *sg = &per_cpu(sched_group_core, group); | |
6037 | return group; | |
1e9f28fa SS |
6038 | } |
6039 | #elif defined(CONFIG_SCHED_MC) | |
41a2d6cf IM |
6040 | static int |
6041 | cpu_to_core_group(int cpu, const cpumask_t *cpu_map, struct sched_group **sg) | |
1e9f28fa | 6042 | { |
6711cab4 SS |
6043 | if (sg) |
6044 | *sg = &per_cpu(sched_group_core, cpu); | |
1e9f28fa SS |
6045 | return cpu; |
6046 | } | |
6047 | #endif | |
6048 | ||
1da177e4 | 6049 | static DEFINE_PER_CPU(struct sched_domain, phys_domains); |
6711cab4 | 6050 | static DEFINE_PER_CPU(struct sched_group, sched_group_phys); |
48f24c4d | 6051 | |
41a2d6cf IM |
6052 | static int |
6053 | cpu_to_phys_group(int cpu, const cpumask_t *cpu_map, struct sched_group **sg) | |
1da177e4 | 6054 | { |
6711cab4 | 6055 | int group; |
48f24c4d | 6056 | #ifdef CONFIG_SCHED_MC |
1e9f28fa | 6057 | cpumask_t mask = cpu_coregroup_map(cpu); |
a616058b | 6058 | cpus_and(mask, mask, *cpu_map); |
6711cab4 | 6059 | group = first_cpu(mask); |
1e9f28fa | 6060 | #elif defined(CONFIG_SCHED_SMT) |
d5a7430d | 6061 | cpumask_t mask = per_cpu(cpu_sibling_map, cpu); |
a616058b | 6062 | cpus_and(mask, mask, *cpu_map); |
6711cab4 | 6063 | group = first_cpu(mask); |
1da177e4 | 6064 | #else |
6711cab4 | 6065 | group = cpu; |
1da177e4 | 6066 | #endif |
6711cab4 SS |
6067 | if (sg) |
6068 | *sg = &per_cpu(sched_group_phys, group); | |
6069 | return group; | |
1da177e4 LT |
6070 | } |
6071 | ||
6072 | #ifdef CONFIG_NUMA | |
1da177e4 | 6073 | /* |
9c1cfda2 JH |
6074 | * The init_sched_build_groups can't handle what we want to do with node |
6075 | * groups, so roll our own. Now each node has its own list of groups which | |
6076 | * gets dynamically allocated. | |
1da177e4 | 6077 | */ |
9c1cfda2 | 6078 | static DEFINE_PER_CPU(struct sched_domain, node_domains); |
d1b55138 | 6079 | static struct sched_group **sched_group_nodes_bycpu[NR_CPUS]; |
1da177e4 | 6080 | |
9c1cfda2 | 6081 | static DEFINE_PER_CPU(struct sched_domain, allnodes_domains); |
6711cab4 | 6082 | static DEFINE_PER_CPU(struct sched_group, sched_group_allnodes); |
9c1cfda2 | 6083 | |
6711cab4 SS |
6084 | static int cpu_to_allnodes_group(int cpu, const cpumask_t *cpu_map, |
6085 | struct sched_group **sg) | |
9c1cfda2 | 6086 | { |
6711cab4 SS |
6087 | cpumask_t nodemask = node_to_cpumask(cpu_to_node(cpu)); |
6088 | int group; | |
6089 | ||
6090 | cpus_and(nodemask, nodemask, *cpu_map); | |
6091 | group = first_cpu(nodemask); | |
6092 | ||
6093 | if (sg) | |
6094 | *sg = &per_cpu(sched_group_allnodes, group); | |
6095 | return group; | |
1da177e4 | 6096 | } |
6711cab4 | 6097 | |
08069033 SS |
6098 | static void init_numa_sched_groups_power(struct sched_group *group_head) |
6099 | { | |
6100 | struct sched_group *sg = group_head; | |
6101 | int j; | |
6102 | ||
6103 | if (!sg) | |
6104 | return; | |
3a5c359a AK |
6105 | do { |
6106 | for_each_cpu_mask(j, sg->cpumask) { | |
6107 | struct sched_domain *sd; | |
08069033 | 6108 | |
3a5c359a AK |
6109 | sd = &per_cpu(phys_domains, j); |
6110 | if (j != first_cpu(sd->groups->cpumask)) { | |
6111 | /* | |
6112 | * Only add "power" once for each | |
6113 | * physical package. | |
6114 | */ | |
6115 | continue; | |
6116 | } | |
08069033 | 6117 | |
3a5c359a AK |
6118 | sg_inc_cpu_power(sg, sd->groups->__cpu_power); |
6119 | } | |
6120 | sg = sg->next; | |
6121 | } while (sg != group_head); | |
08069033 | 6122 | } |
1da177e4 LT |
6123 | #endif |
6124 | ||
a616058b | 6125 | #ifdef CONFIG_NUMA |
51888ca2 SV |
6126 | /* Free memory allocated for various sched_group structures */ |
6127 | static void free_sched_groups(const cpumask_t *cpu_map) | |
6128 | { | |
a616058b | 6129 | int cpu, i; |
51888ca2 SV |
6130 | |
6131 | for_each_cpu_mask(cpu, *cpu_map) { | |
51888ca2 SV |
6132 | struct sched_group **sched_group_nodes |
6133 | = sched_group_nodes_bycpu[cpu]; | |
6134 | ||
51888ca2 SV |
6135 | if (!sched_group_nodes) |
6136 | continue; | |
6137 | ||
6138 | for (i = 0; i < MAX_NUMNODES; i++) { | |
6139 | cpumask_t nodemask = node_to_cpumask(i); | |
6140 | struct sched_group *oldsg, *sg = sched_group_nodes[i]; | |
6141 | ||
6142 | cpus_and(nodemask, nodemask, *cpu_map); | |
6143 | if (cpus_empty(nodemask)) | |
6144 | continue; | |
6145 | ||
6146 | if (sg == NULL) | |
6147 | continue; | |
6148 | sg = sg->next; | |
6149 | next_sg: | |
6150 | oldsg = sg; | |
6151 | sg = sg->next; | |
6152 | kfree(oldsg); | |
6153 | if (oldsg != sched_group_nodes[i]) | |
6154 | goto next_sg; | |
6155 | } | |
6156 | kfree(sched_group_nodes); | |
6157 | sched_group_nodes_bycpu[cpu] = NULL; | |
6158 | } | |
51888ca2 | 6159 | } |
a616058b SS |
6160 | #else |
6161 | static void free_sched_groups(const cpumask_t *cpu_map) | |
6162 | { | |
6163 | } | |
6164 | #endif | |
51888ca2 | 6165 | |
89c4710e SS |
6166 | /* |
6167 | * Initialize sched groups cpu_power. | |
6168 | * | |
6169 | * cpu_power indicates the capacity of sched group, which is used while | |
6170 | * distributing the load between different sched groups in a sched domain. | |
6171 | * Typically cpu_power for all the groups in a sched domain will be same unless | |
6172 | * there are asymmetries in the topology. If there are asymmetries, group | |
6173 | * having more cpu_power will pickup more load compared to the group having | |
6174 | * less cpu_power. | |
6175 | * | |
6176 | * cpu_power will be a multiple of SCHED_LOAD_SCALE. This multiple represents | |
6177 | * the maximum number of tasks a group can handle in the presence of other idle | |
6178 | * or lightly loaded groups in the same sched domain. | |
6179 | */ | |
6180 | static void init_sched_groups_power(int cpu, struct sched_domain *sd) | |
6181 | { | |
6182 | struct sched_domain *child; | |
6183 | struct sched_group *group; | |
6184 | ||
6185 | WARN_ON(!sd || !sd->groups); | |
6186 | ||
6187 | if (cpu != first_cpu(sd->groups->cpumask)) | |
6188 | return; | |
6189 | ||
6190 | child = sd->child; | |
6191 | ||
5517d86b ED |
6192 | sd->groups->__cpu_power = 0; |
6193 | ||
89c4710e SS |
6194 | /* |
6195 | * For perf policy, if the groups in child domain share resources | |
6196 | * (for example cores sharing some portions of the cache hierarchy | |
6197 | * or SMT), then set this domain groups cpu_power such that each group | |
6198 | * can handle only one task, when there are other idle groups in the | |
6199 | * same sched domain. | |
6200 | */ | |
6201 | if (!child || (!(sd->flags & SD_POWERSAVINGS_BALANCE) && | |
6202 | (child->flags & | |
6203 | (SD_SHARE_CPUPOWER | SD_SHARE_PKG_RESOURCES)))) { | |
5517d86b | 6204 | sg_inc_cpu_power(sd->groups, SCHED_LOAD_SCALE); |
89c4710e SS |
6205 | return; |
6206 | } | |
6207 | ||
89c4710e SS |
6208 | /* |
6209 | * add cpu_power of each child group to this groups cpu_power | |
6210 | */ | |
6211 | group = child->groups; | |
6212 | do { | |
5517d86b | 6213 | sg_inc_cpu_power(sd->groups, group->__cpu_power); |
89c4710e SS |
6214 | group = group->next; |
6215 | } while (group != child->groups); | |
6216 | } | |
6217 | ||
1da177e4 | 6218 | /* |
1a20ff27 DG |
6219 | * Build sched domains for a given set of cpus and attach the sched domains |
6220 | * to the individual cpus | |
1da177e4 | 6221 | */ |
51888ca2 | 6222 | static int build_sched_domains(const cpumask_t *cpu_map) |
1da177e4 LT |
6223 | { |
6224 | int i; | |
d1b55138 JH |
6225 | #ifdef CONFIG_NUMA |
6226 | struct sched_group **sched_group_nodes = NULL; | |
6711cab4 | 6227 | int sd_allnodes = 0; |
d1b55138 JH |
6228 | |
6229 | /* | |
6230 | * Allocate the per-node list of sched groups | |
6231 | */ | |
5cf9f062 | 6232 | sched_group_nodes = kcalloc(MAX_NUMNODES, sizeof(struct sched_group *), |
41a2d6cf | 6233 | GFP_KERNEL); |
d1b55138 JH |
6234 | if (!sched_group_nodes) { |
6235 | printk(KERN_WARNING "Can not alloc sched group node list\n"); | |
51888ca2 | 6236 | return -ENOMEM; |
d1b55138 JH |
6237 | } |
6238 | sched_group_nodes_bycpu[first_cpu(*cpu_map)] = sched_group_nodes; | |
6239 | #endif | |
1da177e4 LT |
6240 | |
6241 | /* | |
1a20ff27 | 6242 | * Set up domains for cpus specified by the cpu_map. |
1da177e4 | 6243 | */ |
1a20ff27 | 6244 | for_each_cpu_mask(i, *cpu_map) { |
1da177e4 LT |
6245 | struct sched_domain *sd = NULL, *p; |
6246 | cpumask_t nodemask = node_to_cpumask(cpu_to_node(i)); | |
6247 | ||
1a20ff27 | 6248 | cpus_and(nodemask, nodemask, *cpu_map); |
1da177e4 LT |
6249 | |
6250 | #ifdef CONFIG_NUMA | |
dd41f596 IM |
6251 | if (cpus_weight(*cpu_map) > |
6252 | SD_NODES_PER_DOMAIN*cpus_weight(nodemask)) { | |
9c1cfda2 JH |
6253 | sd = &per_cpu(allnodes_domains, i); |
6254 | *sd = SD_ALLNODES_INIT; | |
6255 | sd->span = *cpu_map; | |
6711cab4 | 6256 | cpu_to_allnodes_group(i, cpu_map, &sd->groups); |
9c1cfda2 | 6257 | p = sd; |
6711cab4 | 6258 | sd_allnodes = 1; |
9c1cfda2 JH |
6259 | } else |
6260 | p = NULL; | |
6261 | ||
1da177e4 | 6262 | sd = &per_cpu(node_domains, i); |
1da177e4 | 6263 | *sd = SD_NODE_INIT; |
9c1cfda2 JH |
6264 | sd->span = sched_domain_node_span(cpu_to_node(i)); |
6265 | sd->parent = p; | |
1a848870 SS |
6266 | if (p) |
6267 | p->child = sd; | |
9c1cfda2 | 6268 | cpus_and(sd->span, sd->span, *cpu_map); |
1da177e4 LT |
6269 | #endif |
6270 | ||
6271 | p = sd; | |
6272 | sd = &per_cpu(phys_domains, i); | |
1da177e4 LT |
6273 | *sd = SD_CPU_INIT; |
6274 | sd->span = nodemask; | |
6275 | sd->parent = p; | |
1a848870 SS |
6276 | if (p) |
6277 | p->child = sd; | |
6711cab4 | 6278 | cpu_to_phys_group(i, cpu_map, &sd->groups); |
1da177e4 | 6279 | |
1e9f28fa SS |
6280 | #ifdef CONFIG_SCHED_MC |
6281 | p = sd; | |
6282 | sd = &per_cpu(core_domains, i); | |
1e9f28fa SS |
6283 | *sd = SD_MC_INIT; |
6284 | sd->span = cpu_coregroup_map(i); | |
6285 | cpus_and(sd->span, sd->span, *cpu_map); | |
6286 | sd->parent = p; | |
1a848870 | 6287 | p->child = sd; |
6711cab4 | 6288 | cpu_to_core_group(i, cpu_map, &sd->groups); |
1e9f28fa SS |
6289 | #endif |
6290 | ||
1da177e4 LT |
6291 | #ifdef CONFIG_SCHED_SMT |
6292 | p = sd; | |
6293 | sd = &per_cpu(cpu_domains, i); | |
1da177e4 | 6294 | *sd = SD_SIBLING_INIT; |
d5a7430d | 6295 | sd->span = per_cpu(cpu_sibling_map, i); |
1a20ff27 | 6296 | cpus_and(sd->span, sd->span, *cpu_map); |
1da177e4 | 6297 | sd->parent = p; |
1a848870 | 6298 | p->child = sd; |
6711cab4 | 6299 | cpu_to_cpu_group(i, cpu_map, &sd->groups); |
1da177e4 LT |
6300 | #endif |
6301 | } | |
6302 | ||
6303 | #ifdef CONFIG_SCHED_SMT | |
6304 | /* Set up CPU (sibling) groups */ | |
9c1cfda2 | 6305 | for_each_cpu_mask(i, *cpu_map) { |
d5a7430d | 6306 | cpumask_t this_sibling_map = per_cpu(cpu_sibling_map, i); |
1a20ff27 | 6307 | cpus_and(this_sibling_map, this_sibling_map, *cpu_map); |
1da177e4 LT |
6308 | if (i != first_cpu(this_sibling_map)) |
6309 | continue; | |
6310 | ||
dd41f596 IM |
6311 | init_sched_build_groups(this_sibling_map, cpu_map, |
6312 | &cpu_to_cpu_group); | |
1da177e4 LT |
6313 | } |
6314 | #endif | |
6315 | ||
1e9f28fa SS |
6316 | #ifdef CONFIG_SCHED_MC |
6317 | /* Set up multi-core groups */ | |
6318 | for_each_cpu_mask(i, *cpu_map) { | |
6319 | cpumask_t this_core_map = cpu_coregroup_map(i); | |
6320 | cpus_and(this_core_map, this_core_map, *cpu_map); | |
6321 | if (i != first_cpu(this_core_map)) | |
6322 | continue; | |
dd41f596 IM |
6323 | init_sched_build_groups(this_core_map, cpu_map, |
6324 | &cpu_to_core_group); | |
1e9f28fa SS |
6325 | } |
6326 | #endif | |
6327 | ||
1da177e4 LT |
6328 | /* Set up physical groups */ |
6329 | for (i = 0; i < MAX_NUMNODES; i++) { | |
6330 | cpumask_t nodemask = node_to_cpumask(i); | |
6331 | ||
1a20ff27 | 6332 | cpus_and(nodemask, nodemask, *cpu_map); |
1da177e4 LT |
6333 | if (cpus_empty(nodemask)) |
6334 | continue; | |
6335 | ||
6711cab4 | 6336 | init_sched_build_groups(nodemask, cpu_map, &cpu_to_phys_group); |
1da177e4 LT |
6337 | } |
6338 | ||
6339 | #ifdef CONFIG_NUMA | |
6340 | /* Set up node groups */ | |
6711cab4 | 6341 | if (sd_allnodes) |
dd41f596 IM |
6342 | init_sched_build_groups(*cpu_map, cpu_map, |
6343 | &cpu_to_allnodes_group); | |
9c1cfda2 JH |
6344 | |
6345 | for (i = 0; i < MAX_NUMNODES; i++) { | |
6346 | /* Set up node groups */ | |
6347 | struct sched_group *sg, *prev; | |
6348 | cpumask_t nodemask = node_to_cpumask(i); | |
6349 | cpumask_t domainspan; | |
6350 | cpumask_t covered = CPU_MASK_NONE; | |
6351 | int j; | |
6352 | ||
6353 | cpus_and(nodemask, nodemask, *cpu_map); | |
d1b55138 JH |
6354 | if (cpus_empty(nodemask)) { |
6355 | sched_group_nodes[i] = NULL; | |
9c1cfda2 | 6356 | continue; |
d1b55138 | 6357 | } |
9c1cfda2 JH |
6358 | |
6359 | domainspan = sched_domain_node_span(i); | |
6360 | cpus_and(domainspan, domainspan, *cpu_map); | |
6361 | ||
15f0b676 | 6362 | sg = kmalloc_node(sizeof(struct sched_group), GFP_KERNEL, i); |
51888ca2 SV |
6363 | if (!sg) { |
6364 | printk(KERN_WARNING "Can not alloc domain group for " | |
6365 | "node %d\n", i); | |
6366 | goto error; | |
6367 | } | |
9c1cfda2 JH |
6368 | sched_group_nodes[i] = sg; |
6369 | for_each_cpu_mask(j, nodemask) { | |
6370 | struct sched_domain *sd; | |
9761eea8 | 6371 | |
9c1cfda2 JH |
6372 | sd = &per_cpu(node_domains, j); |
6373 | sd->groups = sg; | |
9c1cfda2 | 6374 | } |
5517d86b | 6375 | sg->__cpu_power = 0; |
9c1cfda2 | 6376 | sg->cpumask = nodemask; |
51888ca2 | 6377 | sg->next = sg; |
9c1cfda2 JH |
6378 | cpus_or(covered, covered, nodemask); |
6379 | prev = sg; | |
6380 | ||
6381 | for (j = 0; j < MAX_NUMNODES; j++) { | |
6382 | cpumask_t tmp, notcovered; | |
6383 | int n = (i + j) % MAX_NUMNODES; | |
6384 | ||
6385 | cpus_complement(notcovered, covered); | |
6386 | cpus_and(tmp, notcovered, *cpu_map); | |
6387 | cpus_and(tmp, tmp, domainspan); | |
6388 | if (cpus_empty(tmp)) | |
6389 | break; | |
6390 | ||
6391 | nodemask = node_to_cpumask(n); | |
6392 | cpus_and(tmp, tmp, nodemask); | |
6393 | if (cpus_empty(tmp)) | |
6394 | continue; | |
6395 | ||
15f0b676 SV |
6396 | sg = kmalloc_node(sizeof(struct sched_group), |
6397 | GFP_KERNEL, i); | |
9c1cfda2 JH |
6398 | if (!sg) { |
6399 | printk(KERN_WARNING | |
6400 | "Can not alloc domain group for node %d\n", j); | |
51888ca2 | 6401 | goto error; |
9c1cfda2 | 6402 | } |
5517d86b | 6403 | sg->__cpu_power = 0; |
9c1cfda2 | 6404 | sg->cpumask = tmp; |
51888ca2 | 6405 | sg->next = prev->next; |
9c1cfda2 JH |
6406 | cpus_or(covered, covered, tmp); |
6407 | prev->next = sg; | |
6408 | prev = sg; | |
6409 | } | |
9c1cfda2 | 6410 | } |
1da177e4 LT |
6411 | #endif |
6412 | ||
6413 | /* Calculate CPU power for physical packages and nodes */ | |
5c45bf27 | 6414 | #ifdef CONFIG_SCHED_SMT |
1a20ff27 | 6415 | for_each_cpu_mask(i, *cpu_map) { |
dd41f596 IM |
6416 | struct sched_domain *sd = &per_cpu(cpu_domains, i); |
6417 | ||
89c4710e | 6418 | init_sched_groups_power(i, sd); |
5c45bf27 | 6419 | } |
1da177e4 | 6420 | #endif |
1e9f28fa | 6421 | #ifdef CONFIG_SCHED_MC |
5c45bf27 | 6422 | for_each_cpu_mask(i, *cpu_map) { |
dd41f596 IM |
6423 | struct sched_domain *sd = &per_cpu(core_domains, i); |
6424 | ||
89c4710e | 6425 | init_sched_groups_power(i, sd); |
5c45bf27 SS |
6426 | } |
6427 | #endif | |
1e9f28fa | 6428 | |
5c45bf27 | 6429 | for_each_cpu_mask(i, *cpu_map) { |
dd41f596 IM |
6430 | struct sched_domain *sd = &per_cpu(phys_domains, i); |
6431 | ||
89c4710e | 6432 | init_sched_groups_power(i, sd); |
1da177e4 LT |
6433 | } |
6434 | ||
9c1cfda2 | 6435 | #ifdef CONFIG_NUMA |
08069033 SS |
6436 | for (i = 0; i < MAX_NUMNODES; i++) |
6437 | init_numa_sched_groups_power(sched_group_nodes[i]); | |
9c1cfda2 | 6438 | |
6711cab4 SS |
6439 | if (sd_allnodes) { |
6440 | struct sched_group *sg; | |
f712c0c7 | 6441 | |
6711cab4 | 6442 | cpu_to_allnodes_group(first_cpu(*cpu_map), cpu_map, &sg); |
f712c0c7 SS |
6443 | init_numa_sched_groups_power(sg); |
6444 | } | |
9c1cfda2 JH |
6445 | #endif |
6446 | ||
1da177e4 | 6447 | /* Attach the domains */ |
1a20ff27 | 6448 | for_each_cpu_mask(i, *cpu_map) { |
1da177e4 LT |
6449 | struct sched_domain *sd; |
6450 | #ifdef CONFIG_SCHED_SMT | |
6451 | sd = &per_cpu(cpu_domains, i); | |
1e9f28fa SS |
6452 | #elif defined(CONFIG_SCHED_MC) |
6453 | sd = &per_cpu(core_domains, i); | |
1da177e4 LT |
6454 | #else |
6455 | sd = &per_cpu(phys_domains, i); | |
6456 | #endif | |
6457 | cpu_attach_domain(sd, i); | |
6458 | } | |
51888ca2 SV |
6459 | |
6460 | return 0; | |
6461 | ||
a616058b | 6462 | #ifdef CONFIG_NUMA |
51888ca2 SV |
6463 | error: |
6464 | free_sched_groups(cpu_map); | |
6465 | return -ENOMEM; | |
a616058b | 6466 | #endif |
1da177e4 | 6467 | } |
029190c5 PJ |
6468 | |
6469 | static cpumask_t *doms_cur; /* current sched domains */ | |
6470 | static int ndoms_cur; /* number of sched domains in 'doms_cur' */ | |
6471 | ||
6472 | /* | |
6473 | * Special case: If a kmalloc of a doms_cur partition (array of | |
6474 | * cpumask_t) fails, then fallback to a single sched domain, | |
6475 | * as determined by the single cpumask_t fallback_doms. | |
6476 | */ | |
6477 | static cpumask_t fallback_doms; | |
6478 | ||
1a20ff27 | 6479 | /* |
41a2d6cf | 6480 | * Set up scheduler domains and groups. Callers must hold the hotplug lock. |
029190c5 PJ |
6481 | * For now this just excludes isolated cpus, but could be used to |
6482 | * exclude other special cases in the future. | |
1a20ff27 | 6483 | */ |
51888ca2 | 6484 | static int arch_init_sched_domains(const cpumask_t *cpu_map) |
1a20ff27 | 6485 | { |
7378547f MM |
6486 | int err; |
6487 | ||
029190c5 PJ |
6488 | ndoms_cur = 1; |
6489 | doms_cur = kmalloc(sizeof(cpumask_t), GFP_KERNEL); | |
6490 | if (!doms_cur) | |
6491 | doms_cur = &fallback_doms; | |
6492 | cpus_andnot(*doms_cur, *cpu_map, cpu_isolated_map); | |
7378547f | 6493 | err = build_sched_domains(doms_cur); |
6382bc90 | 6494 | register_sched_domain_sysctl(); |
7378547f MM |
6495 | |
6496 | return err; | |
1a20ff27 DG |
6497 | } |
6498 | ||
6499 | static void arch_destroy_sched_domains(const cpumask_t *cpu_map) | |
1da177e4 | 6500 | { |
51888ca2 | 6501 | free_sched_groups(cpu_map); |
9c1cfda2 | 6502 | } |
1da177e4 | 6503 | |
1a20ff27 DG |
6504 | /* |
6505 | * Detach sched domains from a group of cpus specified in cpu_map | |
6506 | * These cpus will now be attached to the NULL domain | |
6507 | */ | |
858119e1 | 6508 | static void detach_destroy_domains(const cpumask_t *cpu_map) |
1a20ff27 DG |
6509 | { |
6510 | int i; | |
6511 | ||
6382bc90 MM |
6512 | unregister_sched_domain_sysctl(); |
6513 | ||
1a20ff27 DG |
6514 | for_each_cpu_mask(i, *cpu_map) |
6515 | cpu_attach_domain(NULL, i); | |
6516 | synchronize_sched(); | |
6517 | arch_destroy_sched_domains(cpu_map); | |
6518 | } | |
6519 | ||
029190c5 PJ |
6520 | /* |
6521 | * Partition sched domains as specified by the 'ndoms_new' | |
41a2d6cf | 6522 | * cpumasks in the array doms_new[] of cpumasks. This compares |
029190c5 PJ |
6523 | * doms_new[] to the current sched domain partitioning, doms_cur[]. |
6524 | * It destroys each deleted domain and builds each new domain. | |
6525 | * | |
6526 | * 'doms_new' is an array of cpumask_t's of length 'ndoms_new'. | |
41a2d6cf IM |
6527 | * The masks don't intersect (don't overlap.) We should setup one |
6528 | * sched domain for each mask. CPUs not in any of the cpumasks will | |
6529 | * not be load balanced. If the same cpumask appears both in the | |
029190c5 PJ |
6530 | * current 'doms_cur' domains and in the new 'doms_new', we can leave |
6531 | * it as it is. | |
6532 | * | |
41a2d6cf IM |
6533 | * The passed in 'doms_new' should be kmalloc'd. This routine takes |
6534 | * ownership of it and will kfree it when done with it. If the caller | |
029190c5 PJ |
6535 | * failed the kmalloc call, then it can pass in doms_new == NULL, |
6536 | * and partition_sched_domains() will fallback to the single partition | |
6537 | * 'fallback_doms'. | |
6538 | * | |
6539 | * Call with hotplug lock held | |
6540 | */ | |
6541 | void partition_sched_domains(int ndoms_new, cpumask_t *doms_new) | |
6542 | { | |
6543 | int i, j; | |
6544 | ||
7378547f MM |
6545 | /* always unregister in case we don't destroy any domains */ |
6546 | unregister_sched_domain_sysctl(); | |
6547 | ||
029190c5 PJ |
6548 | if (doms_new == NULL) { |
6549 | ndoms_new = 1; | |
6550 | doms_new = &fallback_doms; | |
6551 | cpus_andnot(doms_new[0], cpu_online_map, cpu_isolated_map); | |
6552 | } | |
6553 | ||
6554 | /* Destroy deleted domains */ | |
6555 | for (i = 0; i < ndoms_cur; i++) { | |
6556 | for (j = 0; j < ndoms_new; j++) { | |
6557 | if (cpus_equal(doms_cur[i], doms_new[j])) | |
6558 | goto match1; | |
6559 | } | |
6560 | /* no match - a current sched domain not in new doms_new[] */ | |
6561 | detach_destroy_domains(doms_cur + i); | |
6562 | match1: | |
6563 | ; | |
6564 | } | |
6565 | ||
6566 | /* Build new domains */ | |
6567 | for (i = 0; i < ndoms_new; i++) { | |
6568 | for (j = 0; j < ndoms_cur; j++) { | |
6569 | if (cpus_equal(doms_new[i], doms_cur[j])) | |
6570 | goto match2; | |
6571 | } | |
6572 | /* no match - add a new doms_new */ | |
6573 | build_sched_domains(doms_new + i); | |
6574 | match2: | |
6575 | ; | |
6576 | } | |
6577 | ||
6578 | /* Remember the new sched domains */ | |
6579 | if (doms_cur != &fallback_doms) | |
6580 | kfree(doms_cur); | |
6581 | doms_cur = doms_new; | |
6582 | ndoms_cur = ndoms_new; | |
7378547f MM |
6583 | |
6584 | register_sched_domain_sysctl(); | |
029190c5 PJ |
6585 | } |
6586 | ||
5c45bf27 | 6587 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) |
6707de00 | 6588 | static int arch_reinit_sched_domains(void) |
5c45bf27 SS |
6589 | { |
6590 | int err; | |
6591 | ||
5be9361c | 6592 | mutex_lock(&sched_hotcpu_mutex); |
5c45bf27 SS |
6593 | detach_destroy_domains(&cpu_online_map); |
6594 | err = arch_init_sched_domains(&cpu_online_map); | |
5be9361c | 6595 | mutex_unlock(&sched_hotcpu_mutex); |
5c45bf27 SS |
6596 | |
6597 | return err; | |
6598 | } | |
6599 | ||
6600 | static ssize_t sched_power_savings_store(const char *buf, size_t count, int smt) | |
6601 | { | |
6602 | int ret; | |
6603 | ||
6604 | if (buf[0] != '0' && buf[0] != '1') | |
6605 | return -EINVAL; | |
6606 | ||
6607 | if (smt) | |
6608 | sched_smt_power_savings = (buf[0] == '1'); | |
6609 | else | |
6610 | sched_mc_power_savings = (buf[0] == '1'); | |
6611 | ||
6612 | ret = arch_reinit_sched_domains(); | |
6613 | ||
6614 | return ret ? ret : count; | |
6615 | } | |
6616 | ||
5c45bf27 SS |
6617 | #ifdef CONFIG_SCHED_MC |
6618 | static ssize_t sched_mc_power_savings_show(struct sys_device *dev, char *page) | |
6619 | { | |
6620 | return sprintf(page, "%u\n", sched_mc_power_savings); | |
6621 | } | |
48f24c4d IM |
6622 | static ssize_t sched_mc_power_savings_store(struct sys_device *dev, |
6623 | const char *buf, size_t count) | |
5c45bf27 SS |
6624 | { |
6625 | return sched_power_savings_store(buf, count, 0); | |
6626 | } | |
6707de00 AB |
6627 | static SYSDEV_ATTR(sched_mc_power_savings, 0644, sched_mc_power_savings_show, |
6628 | sched_mc_power_savings_store); | |
5c45bf27 SS |
6629 | #endif |
6630 | ||
6631 | #ifdef CONFIG_SCHED_SMT | |
6632 | static ssize_t sched_smt_power_savings_show(struct sys_device *dev, char *page) | |
6633 | { | |
6634 | return sprintf(page, "%u\n", sched_smt_power_savings); | |
6635 | } | |
48f24c4d IM |
6636 | static ssize_t sched_smt_power_savings_store(struct sys_device *dev, |
6637 | const char *buf, size_t count) | |
5c45bf27 SS |
6638 | { |
6639 | return sched_power_savings_store(buf, count, 1); | |
6640 | } | |
6707de00 AB |
6641 | static SYSDEV_ATTR(sched_smt_power_savings, 0644, sched_smt_power_savings_show, |
6642 | sched_smt_power_savings_store); | |
6643 | #endif | |
6644 | ||
6645 | int sched_create_sysfs_power_savings_entries(struct sysdev_class *cls) | |
6646 | { | |
6647 | int err = 0; | |
6648 | ||
6649 | #ifdef CONFIG_SCHED_SMT | |
6650 | if (smt_capable()) | |
6651 | err = sysfs_create_file(&cls->kset.kobj, | |
6652 | &attr_sched_smt_power_savings.attr); | |
6653 | #endif | |
6654 | #ifdef CONFIG_SCHED_MC | |
6655 | if (!err && mc_capable()) | |
6656 | err = sysfs_create_file(&cls->kset.kobj, | |
6657 | &attr_sched_mc_power_savings.attr); | |
6658 | #endif | |
6659 | return err; | |
6660 | } | |
5c45bf27 SS |
6661 | #endif |
6662 | ||
1da177e4 | 6663 | /* |
41a2d6cf | 6664 | * Force a reinitialization of the sched domains hierarchy. The domains |
1da177e4 | 6665 | * and groups cannot be updated in place without racing with the balancing |
41c7ce9a | 6666 | * code, so we temporarily attach all running cpus to the NULL domain |
1da177e4 LT |
6667 | * which will prevent rebalancing while the sched domains are recalculated. |
6668 | */ | |
6669 | static int update_sched_domains(struct notifier_block *nfb, | |
6670 | unsigned long action, void *hcpu) | |
6671 | { | |
1da177e4 LT |
6672 | switch (action) { |
6673 | case CPU_UP_PREPARE: | |
8bb78442 | 6674 | case CPU_UP_PREPARE_FROZEN: |
1da177e4 | 6675 | case CPU_DOWN_PREPARE: |
8bb78442 | 6676 | case CPU_DOWN_PREPARE_FROZEN: |
1a20ff27 | 6677 | detach_destroy_domains(&cpu_online_map); |
1da177e4 LT |
6678 | return NOTIFY_OK; |
6679 | ||
6680 | case CPU_UP_CANCELED: | |
8bb78442 | 6681 | case CPU_UP_CANCELED_FROZEN: |
1da177e4 | 6682 | case CPU_DOWN_FAILED: |
8bb78442 | 6683 | case CPU_DOWN_FAILED_FROZEN: |
1da177e4 | 6684 | case CPU_ONLINE: |
8bb78442 | 6685 | case CPU_ONLINE_FROZEN: |
1da177e4 | 6686 | case CPU_DEAD: |
8bb78442 | 6687 | case CPU_DEAD_FROZEN: |
1da177e4 LT |
6688 | /* |
6689 | * Fall through and re-initialise the domains. | |
6690 | */ | |
6691 | break; | |
6692 | default: | |
6693 | return NOTIFY_DONE; | |
6694 | } | |
6695 | ||
6696 | /* The hotplug lock is already held by cpu_up/cpu_down */ | |
1a20ff27 | 6697 | arch_init_sched_domains(&cpu_online_map); |
1da177e4 LT |
6698 | |
6699 | return NOTIFY_OK; | |
6700 | } | |
1da177e4 LT |
6701 | |
6702 | void __init sched_init_smp(void) | |
6703 | { | |
5c1e1767 NP |
6704 | cpumask_t non_isolated_cpus; |
6705 | ||
5be9361c | 6706 | mutex_lock(&sched_hotcpu_mutex); |
1a20ff27 | 6707 | arch_init_sched_domains(&cpu_online_map); |
e5e5673f | 6708 | cpus_andnot(non_isolated_cpus, cpu_possible_map, cpu_isolated_map); |
5c1e1767 NP |
6709 | if (cpus_empty(non_isolated_cpus)) |
6710 | cpu_set(smp_processor_id(), non_isolated_cpus); | |
5be9361c | 6711 | mutex_unlock(&sched_hotcpu_mutex); |
1da177e4 LT |
6712 | /* XXX: Theoretical race here - CPU may be hotplugged now */ |
6713 | hotcpu_notifier(update_sched_domains, 0); | |
5c1e1767 NP |
6714 | |
6715 | /* Move init over to a non-isolated CPU */ | |
6716 | if (set_cpus_allowed(current, non_isolated_cpus) < 0) | |
6717 | BUG(); | |
19978ca6 | 6718 | sched_init_granularity(); |
1da177e4 LT |
6719 | } |
6720 | #else | |
6721 | void __init sched_init_smp(void) | |
6722 | { | |
19978ca6 | 6723 | sched_init_granularity(); |
1da177e4 LT |
6724 | } |
6725 | #endif /* CONFIG_SMP */ | |
6726 | ||
6727 | int in_sched_functions(unsigned long addr) | |
6728 | { | |
1da177e4 LT |
6729 | return in_lock_functions(addr) || |
6730 | (addr >= (unsigned long)__sched_text_start | |
6731 | && addr < (unsigned long)__sched_text_end); | |
6732 | } | |
6733 | ||
a9957449 | 6734 | static void init_cfs_rq(struct cfs_rq *cfs_rq, struct rq *rq) |
dd41f596 IM |
6735 | { |
6736 | cfs_rq->tasks_timeline = RB_ROOT; | |
dd41f596 IM |
6737 | #ifdef CONFIG_FAIR_GROUP_SCHED |
6738 | cfs_rq->rq = rq; | |
6739 | #endif | |
67e9fb2a | 6740 | cfs_rq->min_vruntime = (u64)(-(1LL << 20)); |
dd41f596 IM |
6741 | } |
6742 | ||
1da177e4 LT |
6743 | void __init sched_init(void) |
6744 | { | |
476f3534 | 6745 | int highest_cpu = 0; |
dd41f596 IM |
6746 | int i, j; |
6747 | ||
0a945022 | 6748 | for_each_possible_cpu(i) { |
dd41f596 | 6749 | struct rt_prio_array *array; |
70b97a7f | 6750 | struct rq *rq; |
1da177e4 LT |
6751 | |
6752 | rq = cpu_rq(i); | |
6753 | spin_lock_init(&rq->lock); | |
fcb99371 | 6754 | lockdep_set_class(&rq->lock, &rq->rq_lock_key); |
7897986b | 6755 | rq->nr_running = 0; |
dd41f596 IM |
6756 | rq->clock = 1; |
6757 | init_cfs_rq(&rq->cfs, rq); | |
6758 | #ifdef CONFIG_FAIR_GROUP_SCHED | |
6759 | INIT_LIST_HEAD(&rq->leaf_cfs_rq_list); | |
3a252015 IM |
6760 | { |
6761 | struct cfs_rq *cfs_rq = &per_cpu(init_cfs_rq, i); | |
6762 | struct sched_entity *se = | |
6763 | &per_cpu(init_sched_entity, i); | |
6764 | ||
6765 | init_cfs_rq_p[i] = cfs_rq; | |
6766 | init_cfs_rq(cfs_rq, rq); | |
4cf86d77 | 6767 | cfs_rq->tg = &init_task_group; |
3a252015 | 6768 | list_add(&cfs_rq->leaf_cfs_rq_list, |
29f59db3 SV |
6769 | &rq->leaf_cfs_rq_list); |
6770 | ||
3a252015 IM |
6771 | init_sched_entity_p[i] = se; |
6772 | se->cfs_rq = &rq->cfs; | |
6773 | se->my_q = cfs_rq; | |
4cf86d77 | 6774 | se->load.weight = init_task_group_load; |
9b5b7751 | 6775 | se->load.inv_weight = |
4cf86d77 | 6776 | div64_64(1ULL<<32, init_task_group_load); |
3a252015 IM |
6777 | se->parent = NULL; |
6778 | } | |
4cf86d77 | 6779 | init_task_group.shares = init_task_group_load; |
5cb350ba | 6780 | spin_lock_init(&init_task_group.lock); |
dd41f596 | 6781 | #endif |
1da177e4 | 6782 | |
dd41f596 IM |
6783 | for (j = 0; j < CPU_LOAD_IDX_MAX; j++) |
6784 | rq->cpu_load[j] = 0; | |
1da177e4 | 6785 | #ifdef CONFIG_SMP |
41c7ce9a | 6786 | rq->sd = NULL; |
1da177e4 | 6787 | rq->active_balance = 0; |
dd41f596 | 6788 | rq->next_balance = jiffies; |
1da177e4 | 6789 | rq->push_cpu = 0; |
0a2966b4 | 6790 | rq->cpu = i; |
1da177e4 LT |
6791 | rq->migration_thread = NULL; |
6792 | INIT_LIST_HEAD(&rq->migration_queue); | |
6793 | #endif | |
6794 | atomic_set(&rq->nr_iowait, 0); | |
6795 | ||
dd41f596 IM |
6796 | array = &rq->rt.active; |
6797 | for (j = 0; j < MAX_RT_PRIO; j++) { | |
6798 | INIT_LIST_HEAD(array->queue + j); | |
6799 | __clear_bit(j, array->bitmap); | |
1da177e4 | 6800 | } |
476f3534 | 6801 | highest_cpu = i; |
dd41f596 IM |
6802 | /* delimiter for bitsearch: */ |
6803 | __set_bit(MAX_RT_PRIO, array->bitmap); | |
1da177e4 LT |
6804 | } |
6805 | ||
2dd73a4f | 6806 | set_load_weight(&init_task); |
b50f60ce | 6807 | |
e107be36 AK |
6808 | #ifdef CONFIG_PREEMPT_NOTIFIERS |
6809 | INIT_HLIST_HEAD(&init_task.preempt_notifiers); | |
6810 | #endif | |
6811 | ||
c9819f45 | 6812 | #ifdef CONFIG_SMP |
476f3534 | 6813 | nr_cpu_ids = highest_cpu + 1; |
c9819f45 CL |
6814 | open_softirq(SCHED_SOFTIRQ, run_rebalance_domains, NULL); |
6815 | #endif | |
6816 | ||
b50f60ce HC |
6817 | #ifdef CONFIG_RT_MUTEXES |
6818 | plist_head_init(&init_task.pi_waiters, &init_task.pi_lock); | |
6819 | #endif | |
6820 | ||
1da177e4 LT |
6821 | /* |
6822 | * The boot idle thread does lazy MMU switching as well: | |
6823 | */ | |
6824 | atomic_inc(&init_mm.mm_count); | |
6825 | enter_lazy_tlb(&init_mm, current); | |
6826 | ||
6827 | /* | |
6828 | * Make us the idle thread. Technically, schedule() should not be | |
6829 | * called from this thread, however somewhere below it might be, | |
6830 | * but because we are the idle thread, we just pick up running again | |
6831 | * when this runqueue becomes "idle". | |
6832 | */ | |
6833 | init_idle(current, smp_processor_id()); | |
dd41f596 IM |
6834 | /* |
6835 | * During early bootup we pretend to be a normal task: | |
6836 | */ | |
6837 | current->sched_class = &fair_sched_class; | |
1da177e4 LT |
6838 | } |
6839 | ||
6840 | #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP | |
6841 | void __might_sleep(char *file, int line) | |
6842 | { | |
48f24c4d | 6843 | #ifdef in_atomic |
1da177e4 LT |
6844 | static unsigned long prev_jiffy; /* ratelimiting */ |
6845 | ||
6846 | if ((in_atomic() || irqs_disabled()) && | |
6847 | system_state == SYSTEM_RUNNING && !oops_in_progress) { | |
6848 | if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy) | |
6849 | return; | |
6850 | prev_jiffy = jiffies; | |
91368d73 | 6851 | printk(KERN_ERR "BUG: sleeping function called from invalid" |
1da177e4 LT |
6852 | " context at %s:%d\n", file, line); |
6853 | printk("in_atomic():%d, irqs_disabled():%d\n", | |
6854 | in_atomic(), irqs_disabled()); | |
a4c410f0 | 6855 | debug_show_held_locks(current); |
3117df04 IM |
6856 | if (irqs_disabled()) |
6857 | print_irqtrace_events(current); | |
1da177e4 LT |
6858 | dump_stack(); |
6859 | } | |
6860 | #endif | |
6861 | } | |
6862 | EXPORT_SYMBOL(__might_sleep); | |
6863 | #endif | |
6864 | ||
6865 | #ifdef CONFIG_MAGIC_SYSRQ | |
3a5e4dc1 AK |
6866 | static void normalize_task(struct rq *rq, struct task_struct *p) |
6867 | { | |
6868 | int on_rq; | |
6869 | update_rq_clock(rq); | |
6870 | on_rq = p->se.on_rq; | |
6871 | if (on_rq) | |
6872 | deactivate_task(rq, p, 0); | |
6873 | __setscheduler(rq, p, SCHED_NORMAL, 0); | |
6874 | if (on_rq) { | |
6875 | activate_task(rq, p, 0); | |
6876 | resched_task(rq->curr); | |
6877 | } | |
6878 | } | |
6879 | ||
1da177e4 LT |
6880 | void normalize_rt_tasks(void) |
6881 | { | |
a0f98a1c | 6882 | struct task_struct *g, *p; |
1da177e4 | 6883 | unsigned long flags; |
70b97a7f | 6884 | struct rq *rq; |
1da177e4 LT |
6885 | |
6886 | read_lock_irq(&tasklist_lock); | |
a0f98a1c | 6887 | do_each_thread(g, p) { |
178be793 IM |
6888 | /* |
6889 | * Only normalize user tasks: | |
6890 | */ | |
6891 | if (!p->mm) | |
6892 | continue; | |
6893 | ||
6cfb0d5d | 6894 | p->se.exec_start = 0; |
6cfb0d5d | 6895 | #ifdef CONFIG_SCHEDSTATS |
dd41f596 | 6896 | p->se.wait_start = 0; |
dd41f596 | 6897 | p->se.sleep_start = 0; |
dd41f596 | 6898 | p->se.block_start = 0; |
6cfb0d5d | 6899 | #endif |
dd41f596 IM |
6900 | task_rq(p)->clock = 0; |
6901 | ||
6902 | if (!rt_task(p)) { | |
6903 | /* | |
6904 | * Renice negative nice level userspace | |
6905 | * tasks back to 0: | |
6906 | */ | |
6907 | if (TASK_NICE(p) < 0 && p->mm) | |
6908 | set_user_nice(p, 0); | |
1da177e4 | 6909 | continue; |
dd41f596 | 6910 | } |
1da177e4 | 6911 | |
b29739f9 IM |
6912 | spin_lock_irqsave(&p->pi_lock, flags); |
6913 | rq = __task_rq_lock(p); | |
1da177e4 | 6914 | |
178be793 | 6915 | normalize_task(rq, p); |
3a5e4dc1 | 6916 | |
b29739f9 IM |
6917 | __task_rq_unlock(rq); |
6918 | spin_unlock_irqrestore(&p->pi_lock, flags); | |
a0f98a1c IM |
6919 | } while_each_thread(g, p); |
6920 | ||
1da177e4 LT |
6921 | read_unlock_irq(&tasklist_lock); |
6922 | } | |
6923 | ||
6924 | #endif /* CONFIG_MAGIC_SYSRQ */ | |
1df5c10a LT |
6925 | |
6926 | #ifdef CONFIG_IA64 | |
6927 | /* | |
6928 | * These functions are only useful for the IA64 MCA handling. | |
6929 | * | |
6930 | * They can only be called when the whole system has been | |
6931 | * stopped - every CPU needs to be quiescent, and no scheduling | |
6932 | * activity can take place. Using them for anything else would | |
6933 | * be a serious bug, and as a result, they aren't even visible | |
6934 | * under any other configuration. | |
6935 | */ | |
6936 | ||
6937 | /** | |
6938 | * curr_task - return the current task for a given cpu. | |
6939 | * @cpu: the processor in question. | |
6940 | * | |
6941 | * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! | |
6942 | */ | |
36c8b586 | 6943 | struct task_struct *curr_task(int cpu) |
1df5c10a LT |
6944 | { |
6945 | return cpu_curr(cpu); | |
6946 | } | |
6947 | ||
6948 | /** | |
6949 | * set_curr_task - set the current task for a given cpu. | |
6950 | * @cpu: the processor in question. | |
6951 | * @p: the task pointer to set. | |
6952 | * | |
6953 | * Description: This function must only be used when non-maskable interrupts | |
41a2d6cf IM |
6954 | * are serviced on a separate stack. It allows the architecture to switch the |
6955 | * notion of the current task on a cpu in a non-blocking manner. This function | |
1df5c10a LT |
6956 | * must be called with all CPU's synchronized, and interrupts disabled, the |
6957 | * and caller must save the original value of the current task (see | |
6958 | * curr_task() above) and restore that value before reenabling interrupts and | |
6959 | * re-starting the system. | |
6960 | * | |
6961 | * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! | |
6962 | */ | |
36c8b586 | 6963 | void set_curr_task(int cpu, struct task_struct *p) |
1df5c10a LT |
6964 | { |
6965 | cpu_curr(cpu) = p; | |
6966 | } | |
6967 | ||
6968 | #endif | |
29f59db3 SV |
6969 | |
6970 | #ifdef CONFIG_FAIR_GROUP_SCHED | |
6971 | ||
29f59db3 | 6972 | /* allocate runqueue etc for a new task group */ |
4cf86d77 | 6973 | struct task_group *sched_create_group(void) |
29f59db3 | 6974 | { |
4cf86d77 | 6975 | struct task_group *tg; |
29f59db3 SV |
6976 | struct cfs_rq *cfs_rq; |
6977 | struct sched_entity *se; | |
9b5b7751 | 6978 | struct rq *rq; |
29f59db3 SV |
6979 | int i; |
6980 | ||
29f59db3 SV |
6981 | tg = kzalloc(sizeof(*tg), GFP_KERNEL); |
6982 | if (!tg) | |
6983 | return ERR_PTR(-ENOMEM); | |
6984 | ||
9b5b7751 | 6985 | tg->cfs_rq = kzalloc(sizeof(cfs_rq) * NR_CPUS, GFP_KERNEL); |
29f59db3 SV |
6986 | if (!tg->cfs_rq) |
6987 | goto err; | |
9b5b7751 | 6988 | tg->se = kzalloc(sizeof(se) * NR_CPUS, GFP_KERNEL); |
29f59db3 SV |
6989 | if (!tg->se) |
6990 | goto err; | |
6991 | ||
6992 | for_each_possible_cpu(i) { | |
9b5b7751 | 6993 | rq = cpu_rq(i); |
29f59db3 SV |
6994 | |
6995 | cfs_rq = kmalloc_node(sizeof(struct cfs_rq), GFP_KERNEL, | |
6996 | cpu_to_node(i)); | |
6997 | if (!cfs_rq) | |
6998 | goto err; | |
6999 | ||
7000 | se = kmalloc_node(sizeof(struct sched_entity), GFP_KERNEL, | |
7001 | cpu_to_node(i)); | |
7002 | if (!se) | |
7003 | goto err; | |
7004 | ||
7005 | memset(cfs_rq, 0, sizeof(struct cfs_rq)); | |
7006 | memset(se, 0, sizeof(struct sched_entity)); | |
7007 | ||
7008 | tg->cfs_rq[i] = cfs_rq; | |
7009 | init_cfs_rq(cfs_rq, rq); | |
7010 | cfs_rq->tg = tg; | |
29f59db3 SV |
7011 | |
7012 | tg->se[i] = se; | |
7013 | se->cfs_rq = &rq->cfs; | |
7014 | se->my_q = cfs_rq; | |
7015 | se->load.weight = NICE_0_LOAD; | |
7016 | se->load.inv_weight = div64_64(1ULL<<32, NICE_0_LOAD); | |
7017 | se->parent = NULL; | |
7018 | } | |
7019 | ||
9b5b7751 SV |
7020 | for_each_possible_cpu(i) { |
7021 | rq = cpu_rq(i); | |
7022 | cfs_rq = tg->cfs_rq[i]; | |
7023 | list_add_rcu(&cfs_rq->leaf_cfs_rq_list, &rq->leaf_cfs_rq_list); | |
7024 | } | |
29f59db3 | 7025 | |
9b5b7751 | 7026 | tg->shares = NICE_0_LOAD; |
5cb350ba | 7027 | spin_lock_init(&tg->lock); |
29f59db3 | 7028 | |
9b5b7751 | 7029 | return tg; |
29f59db3 SV |
7030 | |
7031 | err: | |
7032 | for_each_possible_cpu(i) { | |
a65914b3 | 7033 | if (tg->cfs_rq) |
29f59db3 | 7034 | kfree(tg->cfs_rq[i]); |
a65914b3 | 7035 | if (tg->se) |
29f59db3 SV |
7036 | kfree(tg->se[i]); |
7037 | } | |
a65914b3 IM |
7038 | kfree(tg->cfs_rq); |
7039 | kfree(tg->se); | |
7040 | kfree(tg); | |
29f59db3 SV |
7041 | |
7042 | return ERR_PTR(-ENOMEM); | |
7043 | } | |
7044 | ||
9b5b7751 SV |
7045 | /* rcu callback to free various structures associated with a task group */ |
7046 | static void free_sched_group(struct rcu_head *rhp) | |
29f59db3 | 7047 | { |
ae8393e5 SV |
7048 | struct task_group *tg = container_of(rhp, struct task_group, rcu); |
7049 | struct cfs_rq *cfs_rq; | |
29f59db3 SV |
7050 | struct sched_entity *se; |
7051 | int i; | |
7052 | ||
29f59db3 SV |
7053 | /* now it should be safe to free those cfs_rqs */ |
7054 | for_each_possible_cpu(i) { | |
7055 | cfs_rq = tg->cfs_rq[i]; | |
7056 | kfree(cfs_rq); | |
7057 | ||
7058 | se = tg->se[i]; | |
7059 | kfree(se); | |
7060 | } | |
7061 | ||
7062 | kfree(tg->cfs_rq); | |
7063 | kfree(tg->se); | |
7064 | kfree(tg); | |
7065 | } | |
7066 | ||
9b5b7751 | 7067 | /* Destroy runqueue etc associated with a task group */ |
4cf86d77 | 7068 | void sched_destroy_group(struct task_group *tg) |
29f59db3 | 7069 | { |
7bae49d4 | 7070 | struct cfs_rq *cfs_rq = NULL; |
9b5b7751 | 7071 | int i; |
29f59db3 | 7072 | |
9b5b7751 SV |
7073 | for_each_possible_cpu(i) { |
7074 | cfs_rq = tg->cfs_rq[i]; | |
7075 | list_del_rcu(&cfs_rq->leaf_cfs_rq_list); | |
7076 | } | |
7077 | ||
7bae49d4 | 7078 | BUG_ON(!cfs_rq); |
9b5b7751 SV |
7079 | |
7080 | /* wait for possible concurrent references to cfs_rqs complete */ | |
ae8393e5 | 7081 | call_rcu(&tg->rcu, free_sched_group); |
29f59db3 SV |
7082 | } |
7083 | ||
9b5b7751 | 7084 | /* change task's runqueue when it moves between groups. |
3a252015 IM |
7085 | * The caller of this function should have put the task in its new group |
7086 | * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to | |
7087 | * reflect its new group. | |
9b5b7751 SV |
7088 | */ |
7089 | void sched_move_task(struct task_struct *tsk) | |
29f59db3 SV |
7090 | { |
7091 | int on_rq, running; | |
7092 | unsigned long flags; | |
7093 | struct rq *rq; | |
7094 | ||
7095 | rq = task_rq_lock(tsk, &flags); | |
7096 | ||
dae51f56 | 7097 | if (tsk->sched_class != &fair_sched_class) { |
ce96b5ac | 7098 | set_task_cfs_rq(tsk, task_cpu(tsk)); |
29f59db3 | 7099 | goto done; |
dae51f56 | 7100 | } |
29f59db3 SV |
7101 | |
7102 | update_rq_clock(rq); | |
7103 | ||
7104 | running = task_running(rq, tsk); | |
7105 | on_rq = tsk->se.on_rq; | |
7106 | ||
83b699ed | 7107 | if (on_rq) { |
29f59db3 | 7108 | dequeue_task(rq, tsk, 0); |
83b699ed SV |
7109 | if (unlikely(running)) |
7110 | tsk->sched_class->put_prev_task(rq, tsk); | |
7111 | } | |
29f59db3 | 7112 | |
ce96b5ac | 7113 | set_task_cfs_rq(tsk, task_cpu(tsk)); |
29f59db3 | 7114 | |
83b699ed SV |
7115 | if (on_rq) { |
7116 | if (unlikely(running)) | |
7117 | tsk->sched_class->set_curr_task(rq); | |
7074badb | 7118 | enqueue_task(rq, tsk, 0); |
83b699ed | 7119 | } |
29f59db3 SV |
7120 | |
7121 | done: | |
7122 | task_rq_unlock(rq, &flags); | |
7123 | } | |
7124 | ||
7125 | static void set_se_shares(struct sched_entity *se, unsigned long shares) | |
7126 | { | |
7127 | struct cfs_rq *cfs_rq = se->cfs_rq; | |
7128 | struct rq *rq = cfs_rq->rq; | |
7129 | int on_rq; | |
7130 | ||
7131 | spin_lock_irq(&rq->lock); | |
7132 | ||
7133 | on_rq = se->on_rq; | |
7134 | if (on_rq) | |
7135 | dequeue_entity(cfs_rq, se, 0); | |
7136 | ||
7137 | se->load.weight = shares; | |
7138 | se->load.inv_weight = div64_64((1ULL<<32), shares); | |
7139 | ||
7140 | if (on_rq) | |
7141 | enqueue_entity(cfs_rq, se, 0); | |
7142 | ||
7143 | spin_unlock_irq(&rq->lock); | |
7144 | } | |
7145 | ||
4cf86d77 | 7146 | int sched_group_set_shares(struct task_group *tg, unsigned long shares) |
29f59db3 SV |
7147 | { |
7148 | int i; | |
29f59db3 | 7149 | |
5cb350ba | 7150 | spin_lock(&tg->lock); |
9b5b7751 | 7151 | if (tg->shares == shares) |
5cb350ba | 7152 | goto done; |
29f59db3 | 7153 | |
9b5b7751 | 7154 | tg->shares = shares; |
29f59db3 | 7155 | for_each_possible_cpu(i) |
9b5b7751 | 7156 | set_se_shares(tg->se[i], shares); |
29f59db3 | 7157 | |
5cb350ba DG |
7158 | done: |
7159 | spin_unlock(&tg->lock); | |
9b5b7751 | 7160 | return 0; |
29f59db3 SV |
7161 | } |
7162 | ||
5cb350ba DG |
7163 | unsigned long sched_group_shares(struct task_group *tg) |
7164 | { | |
7165 | return tg->shares; | |
7166 | } | |
7167 | ||
3a252015 | 7168 | #endif /* CONFIG_FAIR_GROUP_SCHED */ |
68318b8e SV |
7169 | |
7170 | #ifdef CONFIG_FAIR_CGROUP_SCHED | |
7171 | ||
7172 | /* return corresponding task_group object of a cgroup */ | |
2b01dfe3 | 7173 | static inline struct task_group *cgroup_tg(struct cgroup *cgrp) |
68318b8e | 7174 | { |
2b01dfe3 PM |
7175 | return container_of(cgroup_subsys_state(cgrp, cpu_cgroup_subsys_id), |
7176 | struct task_group, css); | |
68318b8e SV |
7177 | } |
7178 | ||
7179 | static struct cgroup_subsys_state * | |
2b01dfe3 | 7180 | cpu_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cgrp) |
68318b8e SV |
7181 | { |
7182 | struct task_group *tg; | |
7183 | ||
2b01dfe3 | 7184 | if (!cgrp->parent) { |
68318b8e | 7185 | /* This is early initialization for the top cgroup */ |
2b01dfe3 | 7186 | init_task_group.css.cgroup = cgrp; |
68318b8e SV |
7187 | return &init_task_group.css; |
7188 | } | |
7189 | ||
7190 | /* we support only 1-level deep hierarchical scheduler atm */ | |
2b01dfe3 | 7191 | if (cgrp->parent->parent) |
68318b8e SV |
7192 | return ERR_PTR(-EINVAL); |
7193 | ||
7194 | tg = sched_create_group(); | |
7195 | if (IS_ERR(tg)) | |
7196 | return ERR_PTR(-ENOMEM); | |
7197 | ||
7198 | /* Bind the cgroup to task_group object we just created */ | |
2b01dfe3 | 7199 | tg->css.cgroup = cgrp; |
68318b8e SV |
7200 | |
7201 | return &tg->css; | |
7202 | } | |
7203 | ||
41a2d6cf IM |
7204 | static void |
7205 | cpu_cgroup_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp) | |
68318b8e | 7206 | { |
2b01dfe3 | 7207 | struct task_group *tg = cgroup_tg(cgrp); |
68318b8e SV |
7208 | |
7209 | sched_destroy_group(tg); | |
7210 | } | |
7211 | ||
41a2d6cf IM |
7212 | static int |
7213 | cpu_cgroup_can_attach(struct cgroup_subsys *ss, struct cgroup *cgrp, | |
7214 | struct task_struct *tsk) | |
68318b8e SV |
7215 | { |
7216 | /* We don't support RT-tasks being in separate groups */ | |
7217 | if (tsk->sched_class != &fair_sched_class) | |
7218 | return -EINVAL; | |
7219 | ||
7220 | return 0; | |
7221 | } | |
7222 | ||
7223 | static void | |
2b01dfe3 | 7224 | cpu_cgroup_attach(struct cgroup_subsys *ss, struct cgroup *cgrp, |
68318b8e SV |
7225 | struct cgroup *old_cont, struct task_struct *tsk) |
7226 | { | |
7227 | sched_move_task(tsk); | |
7228 | } | |
7229 | ||
2b01dfe3 PM |
7230 | static int cpu_shares_write_uint(struct cgroup *cgrp, struct cftype *cftype, |
7231 | u64 shareval) | |
68318b8e | 7232 | { |
2b01dfe3 | 7233 | return sched_group_set_shares(cgroup_tg(cgrp), shareval); |
68318b8e SV |
7234 | } |
7235 | ||
2b01dfe3 | 7236 | static u64 cpu_shares_read_uint(struct cgroup *cgrp, struct cftype *cft) |
68318b8e | 7237 | { |
2b01dfe3 | 7238 | struct task_group *tg = cgroup_tg(cgrp); |
68318b8e SV |
7239 | |
7240 | return (u64) tg->shares; | |
7241 | } | |
7242 | ||
fe5c7cc2 PM |
7243 | static struct cftype cpu_files[] = { |
7244 | { | |
7245 | .name = "shares", | |
7246 | .read_uint = cpu_shares_read_uint, | |
7247 | .write_uint = cpu_shares_write_uint, | |
7248 | }, | |
68318b8e SV |
7249 | }; |
7250 | ||
7251 | static int cpu_cgroup_populate(struct cgroup_subsys *ss, struct cgroup *cont) | |
7252 | { | |
fe5c7cc2 | 7253 | return cgroup_add_files(cont, ss, cpu_files, ARRAY_SIZE(cpu_files)); |
68318b8e SV |
7254 | } |
7255 | ||
7256 | struct cgroup_subsys cpu_cgroup_subsys = { | |
38605cae IM |
7257 | .name = "cpu", |
7258 | .create = cpu_cgroup_create, | |
7259 | .destroy = cpu_cgroup_destroy, | |
7260 | .can_attach = cpu_cgroup_can_attach, | |
7261 | .attach = cpu_cgroup_attach, | |
7262 | .populate = cpu_cgroup_populate, | |
7263 | .subsys_id = cpu_cgroup_subsys_id, | |
68318b8e SV |
7264 | .early_init = 1, |
7265 | }; | |
7266 | ||
7267 | #endif /* CONFIG_FAIR_CGROUP_SCHED */ | |
d842de87 SV |
7268 | |
7269 | #ifdef CONFIG_CGROUP_CPUACCT | |
7270 | ||
7271 | /* | |
7272 | * CPU accounting code for task groups. | |
7273 | * | |
7274 | * Based on the work by Paul Menage (menage@google.com) and Balbir Singh | |
7275 | * (balbir@in.ibm.com). | |
7276 | */ | |
7277 | ||
7278 | /* track cpu usage of a group of tasks */ | |
7279 | struct cpuacct { | |
7280 | struct cgroup_subsys_state css; | |
7281 | /* cpuusage holds pointer to a u64-type object on every cpu */ | |
7282 | u64 *cpuusage; | |
7283 | }; | |
7284 | ||
7285 | struct cgroup_subsys cpuacct_subsys; | |
7286 | ||
7287 | /* return cpu accounting group corresponding to this container */ | |
7288 | static inline struct cpuacct *cgroup_ca(struct cgroup *cont) | |
7289 | { | |
7290 | return container_of(cgroup_subsys_state(cont, cpuacct_subsys_id), | |
7291 | struct cpuacct, css); | |
7292 | } | |
7293 | ||
7294 | /* return cpu accounting group to which this task belongs */ | |
7295 | static inline struct cpuacct *task_ca(struct task_struct *tsk) | |
7296 | { | |
7297 | return container_of(task_subsys_state(tsk, cpuacct_subsys_id), | |
7298 | struct cpuacct, css); | |
7299 | } | |
7300 | ||
7301 | /* create a new cpu accounting group */ | |
7302 | static struct cgroup_subsys_state *cpuacct_create( | |
7303 | struct cgroup_subsys *ss, struct cgroup *cont) | |
7304 | { | |
7305 | struct cpuacct *ca = kzalloc(sizeof(*ca), GFP_KERNEL); | |
7306 | ||
7307 | if (!ca) | |
7308 | return ERR_PTR(-ENOMEM); | |
7309 | ||
7310 | ca->cpuusage = alloc_percpu(u64); | |
7311 | if (!ca->cpuusage) { | |
7312 | kfree(ca); | |
7313 | return ERR_PTR(-ENOMEM); | |
7314 | } | |
7315 | ||
7316 | return &ca->css; | |
7317 | } | |
7318 | ||
7319 | /* destroy an existing cpu accounting group */ | |
41a2d6cf IM |
7320 | static void |
7321 | cpuacct_destroy(struct cgroup_subsys *ss, struct cgroup *cont) | |
d842de87 SV |
7322 | { |
7323 | struct cpuacct *ca = cgroup_ca(cont); | |
7324 | ||
7325 | free_percpu(ca->cpuusage); | |
7326 | kfree(ca); | |
7327 | } | |
7328 | ||
7329 | /* return total cpu usage (in nanoseconds) of a group */ | |
7330 | static u64 cpuusage_read(struct cgroup *cont, struct cftype *cft) | |
7331 | { | |
7332 | struct cpuacct *ca = cgroup_ca(cont); | |
7333 | u64 totalcpuusage = 0; | |
7334 | int i; | |
7335 | ||
7336 | for_each_possible_cpu(i) { | |
7337 | u64 *cpuusage = percpu_ptr(ca->cpuusage, i); | |
7338 | ||
7339 | /* | |
7340 | * Take rq->lock to make 64-bit addition safe on 32-bit | |
7341 | * platforms. | |
7342 | */ | |
7343 | spin_lock_irq(&cpu_rq(i)->lock); | |
7344 | totalcpuusage += *cpuusage; | |
7345 | spin_unlock_irq(&cpu_rq(i)->lock); | |
7346 | } | |
7347 | ||
7348 | return totalcpuusage; | |
7349 | } | |
7350 | ||
7351 | static struct cftype files[] = { | |
7352 | { | |
7353 | .name = "usage", | |
7354 | .read_uint = cpuusage_read, | |
7355 | }, | |
7356 | }; | |
7357 | ||
7358 | static int cpuacct_populate(struct cgroup_subsys *ss, struct cgroup *cont) | |
7359 | { | |
7360 | return cgroup_add_files(cont, ss, files, ARRAY_SIZE(files)); | |
7361 | } | |
7362 | ||
7363 | /* | |
7364 | * charge this task's execution time to its accounting group. | |
7365 | * | |
7366 | * called with rq->lock held. | |
7367 | */ | |
7368 | static void cpuacct_charge(struct task_struct *tsk, u64 cputime) | |
7369 | { | |
7370 | struct cpuacct *ca; | |
7371 | ||
7372 | if (!cpuacct_subsys.active) | |
7373 | return; | |
7374 | ||
7375 | ca = task_ca(tsk); | |
7376 | if (ca) { | |
7377 | u64 *cpuusage = percpu_ptr(ca->cpuusage, task_cpu(tsk)); | |
7378 | ||
7379 | *cpuusage += cputime; | |
7380 | } | |
7381 | } | |
7382 | ||
7383 | struct cgroup_subsys cpuacct_subsys = { | |
7384 | .name = "cpuacct", | |
7385 | .create = cpuacct_create, | |
7386 | .destroy = cpuacct_destroy, | |
7387 | .populate = cpuacct_populate, | |
7388 | .subsys_id = cpuacct_subsys_id, | |
7389 | }; | |
7390 | #endif /* CONFIG_CGROUP_CPUACCT */ |