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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; | |
6b2d7700 SV |
171 | |
172 | /* | |
173 | * shares assigned to a task group governs how much of cpu bandwidth | |
174 | * is allocated to the group. The more shares a group has, the more is | |
175 | * the cpu bandwidth allocated to it. | |
176 | * | |
177 | * For ex, lets say that there are three task groups, A, B and C which | |
178 | * have been assigned shares 1000, 2000 and 3000 respectively. Then, | |
179 | * cpu bandwidth allocated by the scheduler to task groups A, B and C | |
180 | * should be: | |
181 | * | |
182 | * Bw(A) = 1000/(1000+2000+3000) * 100 = 16.66% | |
183 | * Bw(B) = 2000/(1000+2000+3000) * 100 = 33.33% | |
184 | * Bw(C) = 3000/(1000+2000+3000) * 100 = 50% | |
185 | * | |
186 | * The weight assigned to a task group's schedulable entities on every | |
187 | * cpu (task_group.se[a_cpu]->load.weight) is derived from the task | |
188 | * group's shares. For ex: lets say that task group A has been | |
189 | * assigned shares of 1000 and there are two CPUs in a system. Then, | |
190 | * | |
191 | * tg_A->se[0]->load.weight = tg_A->se[1]->load.weight = 1000; | |
192 | * | |
193 | * Note: It's not necessary that each of a task's group schedulable | |
194 | * entity have the same weight on all CPUs. If the group | |
195 | * has 2 of its tasks on CPU0 and 1 task on CPU1, then a | |
196 | * better distribution of weight could be: | |
197 | * | |
198 | * tg_A->se[0]->load.weight = 2/3 * 2000 = 1333 | |
199 | * tg_A->se[1]->load.weight = 1/2 * 2000 = 667 | |
200 | * | |
201 | * rebalance_shares() is responsible for distributing the shares of a | |
202 | * task groups like this among the group's schedulable entities across | |
203 | * cpus. | |
204 | * | |
205 | */ | |
29f59db3 | 206 | unsigned long shares; |
6b2d7700 | 207 | |
ae8393e5 | 208 | struct rcu_head rcu; |
29f59db3 SV |
209 | }; |
210 | ||
211 | /* Default task group's sched entity on each cpu */ | |
212 | static DEFINE_PER_CPU(struct sched_entity, init_sched_entity); | |
213 | /* Default task group's cfs_rq on each cpu */ | |
214 | static DEFINE_PER_CPU(struct cfs_rq, init_cfs_rq) ____cacheline_aligned_in_smp; | |
215 | ||
9b5b7751 SV |
216 | static struct sched_entity *init_sched_entity_p[NR_CPUS]; |
217 | static struct cfs_rq *init_cfs_rq_p[NR_CPUS]; | |
29f59db3 | 218 | |
ec2c507f SV |
219 | /* task_group_mutex serializes add/remove of task groups and also changes to |
220 | * a task group's cpu shares. | |
221 | */ | |
222 | static DEFINE_MUTEX(task_group_mutex); | |
223 | ||
a1835615 SV |
224 | /* doms_cur_mutex serializes access to doms_cur[] array */ |
225 | static DEFINE_MUTEX(doms_cur_mutex); | |
226 | ||
6b2d7700 SV |
227 | #ifdef CONFIG_SMP |
228 | /* kernel thread that runs rebalance_shares() periodically */ | |
229 | static struct task_struct *lb_monitor_task; | |
230 | static int load_balance_monitor(void *unused); | |
231 | #endif | |
232 | ||
233 | static void set_se_shares(struct sched_entity *se, unsigned long shares); | |
234 | ||
29f59db3 | 235 | /* Default task group. |
3a252015 | 236 | * Every task in system belong to this group at bootup. |
29f59db3 | 237 | */ |
4cf86d77 | 238 | struct task_group init_task_group = { |
3a252015 IM |
239 | .se = init_sched_entity_p, |
240 | .cfs_rq = init_cfs_rq_p, | |
241 | }; | |
9b5b7751 | 242 | |
24e377a8 | 243 | #ifdef CONFIG_FAIR_USER_SCHED |
93f992cc | 244 | # define INIT_TASK_GROUP_LOAD 2*NICE_0_LOAD |
24e377a8 | 245 | #else |
93f992cc | 246 | # define INIT_TASK_GROUP_LOAD NICE_0_LOAD |
24e377a8 SV |
247 | #endif |
248 | ||
6b2d7700 SV |
249 | #define MIN_GROUP_SHARES 2 |
250 | ||
93f992cc | 251 | static int init_task_group_load = INIT_TASK_GROUP_LOAD; |
29f59db3 SV |
252 | |
253 | /* return group to which a task belongs */ | |
4cf86d77 | 254 | static inline struct task_group *task_group(struct task_struct *p) |
29f59db3 | 255 | { |
4cf86d77 | 256 | struct task_group *tg; |
9b5b7751 | 257 | |
24e377a8 SV |
258 | #ifdef CONFIG_FAIR_USER_SCHED |
259 | tg = p->user->tg; | |
68318b8e SV |
260 | #elif defined(CONFIG_FAIR_CGROUP_SCHED) |
261 | tg = container_of(task_subsys_state(p, cpu_cgroup_subsys_id), | |
262 | struct task_group, css); | |
24e377a8 | 263 | #else |
41a2d6cf | 264 | tg = &init_task_group; |
24e377a8 | 265 | #endif |
9b5b7751 | 266 | return tg; |
29f59db3 SV |
267 | } |
268 | ||
269 | /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */ | |
ce96b5ac | 270 | static inline void set_task_cfs_rq(struct task_struct *p, unsigned int cpu) |
29f59db3 | 271 | { |
ce96b5ac DA |
272 | p->se.cfs_rq = task_group(p)->cfs_rq[cpu]; |
273 | p->se.parent = task_group(p)->se[cpu]; | |
29f59db3 SV |
274 | } |
275 | ||
ec2c507f SV |
276 | static inline void lock_task_group_list(void) |
277 | { | |
278 | mutex_lock(&task_group_mutex); | |
279 | } | |
280 | ||
281 | static inline void unlock_task_group_list(void) | |
282 | { | |
283 | mutex_unlock(&task_group_mutex); | |
284 | } | |
285 | ||
a1835615 SV |
286 | static inline void lock_doms_cur(void) |
287 | { | |
288 | mutex_lock(&doms_cur_mutex); | |
289 | } | |
290 | ||
291 | static inline void unlock_doms_cur(void) | |
292 | { | |
293 | mutex_unlock(&doms_cur_mutex); | |
294 | } | |
295 | ||
29f59db3 SV |
296 | #else |
297 | ||
ce96b5ac | 298 | static inline void set_task_cfs_rq(struct task_struct *p, unsigned int cpu) { } |
ec2c507f SV |
299 | static inline void lock_task_group_list(void) { } |
300 | static inline void unlock_task_group_list(void) { } | |
a1835615 SV |
301 | static inline void lock_doms_cur(void) { } |
302 | static inline void unlock_doms_cur(void) { } | |
29f59db3 SV |
303 | |
304 | #endif /* CONFIG_FAIR_GROUP_SCHED */ | |
305 | ||
6aa645ea IM |
306 | /* CFS-related fields in a runqueue */ |
307 | struct cfs_rq { | |
308 | struct load_weight load; | |
309 | unsigned long nr_running; | |
310 | ||
6aa645ea | 311 | u64 exec_clock; |
e9acbff6 | 312 | u64 min_vruntime; |
6aa645ea IM |
313 | |
314 | struct rb_root tasks_timeline; | |
315 | struct rb_node *rb_leftmost; | |
316 | struct rb_node *rb_load_balance_curr; | |
6aa645ea IM |
317 | /* 'curr' points to currently running entity on this cfs_rq. |
318 | * It is set to NULL otherwise (i.e when none are currently running). | |
319 | */ | |
320 | struct sched_entity *curr; | |
ddc97297 PZ |
321 | |
322 | unsigned long nr_spread_over; | |
323 | ||
62160e3f | 324 | #ifdef CONFIG_FAIR_GROUP_SCHED |
6aa645ea IM |
325 | struct rq *rq; /* cpu runqueue to which this cfs_rq is attached */ |
326 | ||
41a2d6cf IM |
327 | /* |
328 | * leaf cfs_rqs are those that hold tasks (lowest schedulable entity in | |
6aa645ea IM |
329 | * a hierarchy). Non-leaf lrqs hold other higher schedulable entities |
330 | * (like users, containers etc.) | |
331 | * | |
332 | * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This | |
333 | * list is used during load balance. | |
334 | */ | |
41a2d6cf IM |
335 | struct list_head leaf_cfs_rq_list; |
336 | struct task_group *tg; /* group that "owns" this runqueue */ | |
6aa645ea IM |
337 | #endif |
338 | }; | |
1da177e4 | 339 | |
6aa645ea IM |
340 | /* Real-Time classes' related field in a runqueue: */ |
341 | struct rt_rq { | |
342 | struct rt_prio_array active; | |
343 | int rt_load_balance_idx; | |
344 | struct list_head *rt_load_balance_head, *rt_load_balance_curr; | |
63489e45 | 345 | unsigned long rt_nr_running; |
73fe6aae | 346 | unsigned long rt_nr_migratory; |
764a9d6f SR |
347 | /* highest queued rt task prio */ |
348 | int highest_prio; | |
6aa645ea IM |
349 | }; |
350 | ||
1da177e4 LT |
351 | /* |
352 | * This is the main, per-CPU runqueue data structure. | |
353 | * | |
354 | * Locking rule: those places that want to lock multiple runqueues | |
355 | * (such as the load balancing or the thread migration code), lock | |
356 | * acquire operations must be ordered by ascending &runqueue. | |
357 | */ | |
70b97a7f | 358 | struct rq { |
d8016491 IM |
359 | /* runqueue lock: */ |
360 | spinlock_t lock; | |
1da177e4 LT |
361 | |
362 | /* | |
363 | * nr_running and cpu_load should be in the same cacheline because | |
364 | * remote CPUs use both these fields when doing load calculation. | |
365 | */ | |
366 | unsigned long nr_running; | |
6aa645ea IM |
367 | #define CPU_LOAD_IDX_MAX 5 |
368 | unsigned long cpu_load[CPU_LOAD_IDX_MAX]; | |
bdecea3a | 369 | unsigned char idle_at_tick; |
46cb4b7c SS |
370 | #ifdef CONFIG_NO_HZ |
371 | unsigned char in_nohz_recently; | |
372 | #endif | |
d8016491 IM |
373 | /* capture load from *all* tasks on this cpu: */ |
374 | struct load_weight load; | |
6aa645ea IM |
375 | unsigned long nr_load_updates; |
376 | u64 nr_switches; | |
377 | ||
378 | struct cfs_rq cfs; | |
379 | #ifdef CONFIG_FAIR_GROUP_SCHED | |
d8016491 IM |
380 | /* list of leaf cfs_rq on this cpu: */ |
381 | struct list_head leaf_cfs_rq_list; | |
1da177e4 | 382 | #endif |
41a2d6cf | 383 | struct rt_rq rt; |
1da177e4 LT |
384 | |
385 | /* | |
386 | * This is part of a global counter where only the total sum | |
387 | * over all CPUs matters. A task can increase this counter on | |
388 | * one CPU and if it got migrated afterwards it may decrease | |
389 | * it on another CPU. Always updated under the runqueue lock: | |
390 | */ | |
391 | unsigned long nr_uninterruptible; | |
392 | ||
36c8b586 | 393 | struct task_struct *curr, *idle; |
c9819f45 | 394 | unsigned long next_balance; |
1da177e4 | 395 | struct mm_struct *prev_mm; |
6aa645ea | 396 | |
6aa645ea IM |
397 | u64 clock, prev_clock_raw; |
398 | s64 clock_max_delta; | |
399 | ||
400 | unsigned int clock_warps, clock_overflows; | |
2aa44d05 IM |
401 | u64 idle_clock; |
402 | unsigned int clock_deep_idle_events; | |
529c7726 | 403 | u64 tick_timestamp; |
6aa645ea | 404 | |
1da177e4 LT |
405 | atomic_t nr_iowait; |
406 | ||
407 | #ifdef CONFIG_SMP | |
408 | struct sched_domain *sd; | |
409 | ||
410 | /* For active balancing */ | |
411 | int active_balance; | |
412 | int push_cpu; | |
d8016491 IM |
413 | /* cpu of this runqueue: */ |
414 | int cpu; | |
1da177e4 | 415 | |
36c8b586 | 416 | struct task_struct *migration_thread; |
1da177e4 LT |
417 | struct list_head migration_queue; |
418 | #endif | |
419 | ||
420 | #ifdef CONFIG_SCHEDSTATS | |
421 | /* latency stats */ | |
422 | struct sched_info rq_sched_info; | |
423 | ||
424 | /* sys_sched_yield() stats */ | |
480b9434 KC |
425 | unsigned int yld_exp_empty; |
426 | unsigned int yld_act_empty; | |
427 | unsigned int yld_both_empty; | |
428 | unsigned int yld_count; | |
1da177e4 LT |
429 | |
430 | /* schedule() stats */ | |
480b9434 KC |
431 | unsigned int sched_switch; |
432 | unsigned int sched_count; | |
433 | unsigned int sched_goidle; | |
1da177e4 LT |
434 | |
435 | /* try_to_wake_up() stats */ | |
480b9434 KC |
436 | unsigned int ttwu_count; |
437 | unsigned int ttwu_local; | |
b8efb561 IM |
438 | |
439 | /* BKL stats */ | |
480b9434 | 440 | unsigned int bkl_count; |
1da177e4 | 441 | #endif |
fcb99371 | 442 | struct lock_class_key rq_lock_key; |
1da177e4 LT |
443 | }; |
444 | ||
f34e3b61 | 445 | static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues); |
1da177e4 | 446 | |
dd41f596 IM |
447 | static inline void check_preempt_curr(struct rq *rq, struct task_struct *p) |
448 | { | |
449 | rq->curr->sched_class->check_preempt_curr(rq, p); | |
450 | } | |
451 | ||
0a2966b4 CL |
452 | static inline int cpu_of(struct rq *rq) |
453 | { | |
454 | #ifdef CONFIG_SMP | |
455 | return rq->cpu; | |
456 | #else | |
457 | return 0; | |
458 | #endif | |
459 | } | |
460 | ||
20d315d4 | 461 | /* |
b04a0f4c IM |
462 | * Update the per-runqueue clock, as finegrained as the platform can give |
463 | * us, but without assuming monotonicity, etc.: | |
20d315d4 | 464 | */ |
b04a0f4c | 465 | static void __update_rq_clock(struct rq *rq) |
20d315d4 IM |
466 | { |
467 | u64 prev_raw = rq->prev_clock_raw; | |
468 | u64 now = sched_clock(); | |
469 | s64 delta = now - prev_raw; | |
470 | u64 clock = rq->clock; | |
471 | ||
b04a0f4c IM |
472 | #ifdef CONFIG_SCHED_DEBUG |
473 | WARN_ON_ONCE(cpu_of(rq) != smp_processor_id()); | |
474 | #endif | |
20d315d4 IM |
475 | /* |
476 | * Protect against sched_clock() occasionally going backwards: | |
477 | */ | |
478 | if (unlikely(delta < 0)) { | |
479 | clock++; | |
480 | rq->clock_warps++; | |
481 | } else { | |
482 | /* | |
483 | * Catch too large forward jumps too: | |
484 | */ | |
529c7726 IM |
485 | if (unlikely(clock + delta > rq->tick_timestamp + TICK_NSEC)) { |
486 | if (clock < rq->tick_timestamp + TICK_NSEC) | |
487 | clock = rq->tick_timestamp + TICK_NSEC; | |
488 | else | |
489 | clock++; | |
20d315d4 IM |
490 | rq->clock_overflows++; |
491 | } else { | |
492 | if (unlikely(delta > rq->clock_max_delta)) | |
493 | rq->clock_max_delta = delta; | |
494 | clock += delta; | |
495 | } | |
496 | } | |
497 | ||
498 | rq->prev_clock_raw = now; | |
499 | rq->clock = clock; | |
b04a0f4c | 500 | } |
20d315d4 | 501 | |
b04a0f4c IM |
502 | static void update_rq_clock(struct rq *rq) |
503 | { | |
504 | if (likely(smp_processor_id() == cpu_of(rq))) | |
505 | __update_rq_clock(rq); | |
20d315d4 IM |
506 | } |
507 | ||
674311d5 NP |
508 | /* |
509 | * The domain tree (rq->sd) is protected by RCU's quiescent state transition. | |
1a20ff27 | 510 | * See detach_destroy_domains: synchronize_sched for details. |
674311d5 NP |
511 | * |
512 | * The domain tree of any CPU may only be accessed from within | |
513 | * preempt-disabled sections. | |
514 | */ | |
48f24c4d IM |
515 | #define for_each_domain(cpu, __sd) \ |
516 | for (__sd = rcu_dereference(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent) | |
1da177e4 LT |
517 | |
518 | #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu))) | |
519 | #define this_rq() (&__get_cpu_var(runqueues)) | |
520 | #define task_rq(p) cpu_rq(task_cpu(p)) | |
521 | #define cpu_curr(cpu) (cpu_rq(cpu)->curr) | |
522 | ||
bf5c91ba IM |
523 | /* |
524 | * Tunables that become constants when CONFIG_SCHED_DEBUG is off: | |
525 | */ | |
526 | #ifdef CONFIG_SCHED_DEBUG | |
527 | # define const_debug __read_mostly | |
528 | #else | |
529 | # define const_debug static const | |
530 | #endif | |
531 | ||
532 | /* | |
533 | * Debugging: various feature bits | |
534 | */ | |
535 | enum { | |
bbdba7c0 | 536 | SCHED_FEAT_NEW_FAIR_SLEEPERS = 1, |
9612633a IM |
537 | SCHED_FEAT_WAKEUP_PREEMPT = 2, |
538 | SCHED_FEAT_START_DEBIT = 4, | |
41a2d6cf IM |
539 | SCHED_FEAT_TREE_AVG = 8, |
540 | SCHED_FEAT_APPROX_AVG = 16, | |
bf5c91ba IM |
541 | }; |
542 | ||
543 | const_debug unsigned int sysctl_sched_features = | |
8401f775 | 544 | SCHED_FEAT_NEW_FAIR_SLEEPERS * 1 | |
9612633a | 545 | SCHED_FEAT_WAKEUP_PREEMPT * 1 | |
8401f775 IM |
546 | SCHED_FEAT_START_DEBIT * 1 | |
547 | SCHED_FEAT_TREE_AVG * 0 | | |
9612633a | 548 | SCHED_FEAT_APPROX_AVG * 0; |
bf5c91ba IM |
549 | |
550 | #define sched_feat(x) (sysctl_sched_features & SCHED_FEAT_##x) | |
551 | ||
b82d9fdd PZ |
552 | /* |
553 | * Number of tasks to iterate in a single balance run. | |
554 | * Limited because this is done with IRQs disabled. | |
555 | */ | |
556 | const_debug unsigned int sysctl_sched_nr_migrate = 32; | |
557 | ||
e436d800 IM |
558 | /* |
559 | * For kernel-internal use: high-speed (but slightly incorrect) per-cpu | |
560 | * clock constructed from sched_clock(): | |
561 | */ | |
562 | unsigned long long cpu_clock(int cpu) | |
563 | { | |
e436d800 IM |
564 | unsigned long long now; |
565 | unsigned long flags; | |
b04a0f4c | 566 | struct rq *rq; |
e436d800 | 567 | |
2cd4d0ea | 568 | local_irq_save(flags); |
b04a0f4c | 569 | rq = cpu_rq(cpu); |
8ced5f69 IM |
570 | /* |
571 | * Only call sched_clock() if the scheduler has already been | |
572 | * initialized (some code might call cpu_clock() very early): | |
573 | */ | |
574 | if (rq->idle) | |
575 | update_rq_clock(rq); | |
b04a0f4c | 576 | now = rq->clock; |
2cd4d0ea | 577 | local_irq_restore(flags); |
e436d800 IM |
578 | |
579 | return now; | |
580 | } | |
a58f6f25 | 581 | EXPORT_SYMBOL_GPL(cpu_clock); |
e436d800 | 582 | |
1da177e4 | 583 | #ifndef prepare_arch_switch |
4866cde0 NP |
584 | # define prepare_arch_switch(next) do { } while (0) |
585 | #endif | |
586 | #ifndef finish_arch_switch | |
587 | # define finish_arch_switch(prev) do { } while (0) | |
588 | #endif | |
589 | ||
051a1d1a DA |
590 | static inline int task_current(struct rq *rq, struct task_struct *p) |
591 | { | |
592 | return rq->curr == p; | |
593 | } | |
594 | ||
4866cde0 | 595 | #ifndef __ARCH_WANT_UNLOCKED_CTXSW |
70b97a7f | 596 | static inline int task_running(struct rq *rq, struct task_struct *p) |
4866cde0 | 597 | { |
051a1d1a | 598 | return task_current(rq, p); |
4866cde0 NP |
599 | } |
600 | ||
70b97a7f | 601 | static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next) |
4866cde0 NP |
602 | { |
603 | } | |
604 | ||
70b97a7f | 605 | static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev) |
4866cde0 | 606 | { |
da04c035 IM |
607 | #ifdef CONFIG_DEBUG_SPINLOCK |
608 | /* this is a valid case when another task releases the spinlock */ | |
609 | rq->lock.owner = current; | |
610 | #endif | |
8a25d5de IM |
611 | /* |
612 | * If we are tracking spinlock dependencies then we have to | |
613 | * fix up the runqueue lock - which gets 'carried over' from | |
614 | * prev into current: | |
615 | */ | |
616 | spin_acquire(&rq->lock.dep_map, 0, 0, _THIS_IP_); | |
617 | ||
4866cde0 NP |
618 | spin_unlock_irq(&rq->lock); |
619 | } | |
620 | ||
621 | #else /* __ARCH_WANT_UNLOCKED_CTXSW */ | |
70b97a7f | 622 | static inline int task_running(struct rq *rq, struct task_struct *p) |
4866cde0 NP |
623 | { |
624 | #ifdef CONFIG_SMP | |
625 | return p->oncpu; | |
626 | #else | |
051a1d1a | 627 | return task_current(rq, p); |
4866cde0 NP |
628 | #endif |
629 | } | |
630 | ||
70b97a7f | 631 | static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next) |
4866cde0 NP |
632 | { |
633 | #ifdef CONFIG_SMP | |
634 | /* | |
635 | * We can optimise this out completely for !SMP, because the | |
636 | * SMP rebalancing from interrupt is the only thing that cares | |
637 | * here. | |
638 | */ | |
639 | next->oncpu = 1; | |
640 | #endif | |
641 | #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW | |
642 | spin_unlock_irq(&rq->lock); | |
643 | #else | |
644 | spin_unlock(&rq->lock); | |
645 | #endif | |
646 | } | |
647 | ||
70b97a7f | 648 | static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev) |
4866cde0 NP |
649 | { |
650 | #ifdef CONFIG_SMP | |
651 | /* | |
652 | * After ->oncpu is cleared, the task can be moved to a different CPU. | |
653 | * We must ensure this doesn't happen until the switch is completely | |
654 | * finished. | |
655 | */ | |
656 | smp_wmb(); | |
657 | prev->oncpu = 0; | |
658 | #endif | |
659 | #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW | |
660 | local_irq_enable(); | |
1da177e4 | 661 | #endif |
4866cde0 NP |
662 | } |
663 | #endif /* __ARCH_WANT_UNLOCKED_CTXSW */ | |
1da177e4 | 664 | |
b29739f9 IM |
665 | /* |
666 | * __task_rq_lock - lock the runqueue a given task resides on. | |
667 | * Must be called interrupts disabled. | |
668 | */ | |
70b97a7f | 669 | static inline struct rq *__task_rq_lock(struct task_struct *p) |
b29739f9 IM |
670 | __acquires(rq->lock) |
671 | { | |
3a5c359a AK |
672 | for (;;) { |
673 | struct rq *rq = task_rq(p); | |
674 | spin_lock(&rq->lock); | |
675 | if (likely(rq == task_rq(p))) | |
676 | return rq; | |
b29739f9 | 677 | spin_unlock(&rq->lock); |
b29739f9 | 678 | } |
b29739f9 IM |
679 | } |
680 | ||
1da177e4 LT |
681 | /* |
682 | * task_rq_lock - lock the runqueue a given task resides on and disable | |
41a2d6cf | 683 | * interrupts. Note the ordering: we can safely lookup the task_rq without |
1da177e4 LT |
684 | * explicitly disabling preemption. |
685 | */ | |
70b97a7f | 686 | static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags) |
1da177e4 LT |
687 | __acquires(rq->lock) |
688 | { | |
70b97a7f | 689 | struct rq *rq; |
1da177e4 | 690 | |
3a5c359a AK |
691 | for (;;) { |
692 | local_irq_save(*flags); | |
693 | rq = task_rq(p); | |
694 | spin_lock(&rq->lock); | |
695 | if (likely(rq == task_rq(p))) | |
696 | return rq; | |
1da177e4 | 697 | spin_unlock_irqrestore(&rq->lock, *flags); |
1da177e4 | 698 | } |
1da177e4 LT |
699 | } |
700 | ||
a9957449 | 701 | static void __task_rq_unlock(struct rq *rq) |
b29739f9 IM |
702 | __releases(rq->lock) |
703 | { | |
704 | spin_unlock(&rq->lock); | |
705 | } | |
706 | ||
70b97a7f | 707 | static inline void task_rq_unlock(struct rq *rq, unsigned long *flags) |
1da177e4 LT |
708 | __releases(rq->lock) |
709 | { | |
710 | spin_unlock_irqrestore(&rq->lock, *flags); | |
711 | } | |
712 | ||
1da177e4 | 713 | /* |
cc2a73b5 | 714 | * this_rq_lock - lock this runqueue and disable interrupts. |
1da177e4 | 715 | */ |
a9957449 | 716 | static struct rq *this_rq_lock(void) |
1da177e4 LT |
717 | __acquires(rq->lock) |
718 | { | |
70b97a7f | 719 | struct rq *rq; |
1da177e4 LT |
720 | |
721 | local_irq_disable(); | |
722 | rq = this_rq(); | |
723 | spin_lock(&rq->lock); | |
724 | ||
725 | return rq; | |
726 | } | |
727 | ||
1b9f19c2 | 728 | /* |
2aa44d05 | 729 | * We are going deep-idle (irqs are disabled): |
1b9f19c2 | 730 | */ |
2aa44d05 | 731 | void sched_clock_idle_sleep_event(void) |
1b9f19c2 | 732 | { |
2aa44d05 IM |
733 | struct rq *rq = cpu_rq(smp_processor_id()); |
734 | ||
735 | spin_lock(&rq->lock); | |
736 | __update_rq_clock(rq); | |
737 | spin_unlock(&rq->lock); | |
738 | rq->clock_deep_idle_events++; | |
739 | } | |
740 | EXPORT_SYMBOL_GPL(sched_clock_idle_sleep_event); | |
741 | ||
742 | /* | |
743 | * We just idled delta nanoseconds (called with irqs disabled): | |
744 | */ | |
745 | void sched_clock_idle_wakeup_event(u64 delta_ns) | |
746 | { | |
747 | struct rq *rq = cpu_rq(smp_processor_id()); | |
748 | u64 now = sched_clock(); | |
1b9f19c2 | 749 | |
2bacec8c | 750 | touch_softlockup_watchdog(); |
2aa44d05 IM |
751 | rq->idle_clock += delta_ns; |
752 | /* | |
753 | * Override the previous timestamp and ignore all | |
754 | * sched_clock() deltas that occured while we idled, | |
755 | * and use the PM-provided delta_ns to advance the | |
756 | * rq clock: | |
757 | */ | |
758 | spin_lock(&rq->lock); | |
759 | rq->prev_clock_raw = now; | |
760 | rq->clock += delta_ns; | |
761 | spin_unlock(&rq->lock); | |
1b9f19c2 | 762 | } |
2aa44d05 | 763 | EXPORT_SYMBOL_GPL(sched_clock_idle_wakeup_event); |
1b9f19c2 | 764 | |
c24d20db IM |
765 | /* |
766 | * resched_task - mark a task 'to be rescheduled now'. | |
767 | * | |
768 | * On UP this means the setting of the need_resched flag, on SMP it | |
769 | * might also involve a cross-CPU call to trigger the scheduler on | |
770 | * the target CPU. | |
771 | */ | |
772 | #ifdef CONFIG_SMP | |
773 | ||
774 | #ifndef tsk_is_polling | |
775 | #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG) | |
776 | #endif | |
777 | ||
778 | static void resched_task(struct task_struct *p) | |
779 | { | |
780 | int cpu; | |
781 | ||
782 | assert_spin_locked(&task_rq(p)->lock); | |
783 | ||
784 | if (unlikely(test_tsk_thread_flag(p, TIF_NEED_RESCHED))) | |
785 | return; | |
786 | ||
787 | set_tsk_thread_flag(p, TIF_NEED_RESCHED); | |
788 | ||
789 | cpu = task_cpu(p); | |
790 | if (cpu == smp_processor_id()) | |
791 | return; | |
792 | ||
793 | /* NEED_RESCHED must be visible before we test polling */ | |
794 | smp_mb(); | |
795 | if (!tsk_is_polling(p)) | |
796 | smp_send_reschedule(cpu); | |
797 | } | |
798 | ||
799 | static void resched_cpu(int cpu) | |
800 | { | |
801 | struct rq *rq = cpu_rq(cpu); | |
802 | unsigned long flags; | |
803 | ||
804 | if (!spin_trylock_irqsave(&rq->lock, flags)) | |
805 | return; | |
806 | resched_task(cpu_curr(cpu)); | |
807 | spin_unlock_irqrestore(&rq->lock, flags); | |
808 | } | |
809 | #else | |
810 | static inline void resched_task(struct task_struct *p) | |
811 | { | |
812 | assert_spin_locked(&task_rq(p)->lock); | |
813 | set_tsk_need_resched(p); | |
814 | } | |
815 | #endif | |
816 | ||
45bf76df IM |
817 | #if BITS_PER_LONG == 32 |
818 | # define WMULT_CONST (~0UL) | |
819 | #else | |
820 | # define WMULT_CONST (1UL << 32) | |
821 | #endif | |
822 | ||
823 | #define WMULT_SHIFT 32 | |
824 | ||
194081eb IM |
825 | /* |
826 | * Shift right and round: | |
827 | */ | |
cf2ab469 | 828 | #define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y)) |
194081eb | 829 | |
cb1c4fc9 | 830 | static unsigned long |
45bf76df IM |
831 | calc_delta_mine(unsigned long delta_exec, unsigned long weight, |
832 | struct load_weight *lw) | |
833 | { | |
834 | u64 tmp; | |
835 | ||
836 | if (unlikely(!lw->inv_weight)) | |
194081eb | 837 | lw->inv_weight = (WMULT_CONST - lw->weight/2) / lw->weight + 1; |
45bf76df IM |
838 | |
839 | tmp = (u64)delta_exec * weight; | |
840 | /* | |
841 | * Check whether we'd overflow the 64-bit multiplication: | |
842 | */ | |
194081eb | 843 | if (unlikely(tmp > WMULT_CONST)) |
cf2ab469 | 844 | tmp = SRR(SRR(tmp, WMULT_SHIFT/2) * lw->inv_weight, |
194081eb IM |
845 | WMULT_SHIFT/2); |
846 | else | |
cf2ab469 | 847 | tmp = SRR(tmp * lw->inv_weight, WMULT_SHIFT); |
45bf76df | 848 | |
ecf691da | 849 | return (unsigned long)min(tmp, (u64)(unsigned long)LONG_MAX); |
45bf76df IM |
850 | } |
851 | ||
852 | static inline unsigned long | |
853 | calc_delta_fair(unsigned long delta_exec, struct load_weight *lw) | |
854 | { | |
855 | return calc_delta_mine(delta_exec, NICE_0_LOAD, lw); | |
856 | } | |
857 | ||
1091985b | 858 | static inline void update_load_add(struct load_weight *lw, unsigned long inc) |
45bf76df IM |
859 | { |
860 | lw->weight += inc; | |
45bf76df IM |
861 | } |
862 | ||
1091985b | 863 | static inline void update_load_sub(struct load_weight *lw, unsigned long dec) |
45bf76df IM |
864 | { |
865 | lw->weight -= dec; | |
45bf76df IM |
866 | } |
867 | ||
2dd73a4f PW |
868 | /* |
869 | * To aid in avoiding the subversion of "niceness" due to uneven distribution | |
870 | * of tasks with abnormal "nice" values across CPUs the contribution that | |
871 | * each task makes to its run queue's load is weighted according to its | |
41a2d6cf | 872 | * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a |
2dd73a4f PW |
873 | * scaled version of the new time slice allocation that they receive on time |
874 | * slice expiry etc. | |
875 | */ | |
876 | ||
dd41f596 IM |
877 | #define WEIGHT_IDLEPRIO 2 |
878 | #define WMULT_IDLEPRIO (1 << 31) | |
879 | ||
880 | /* | |
881 | * Nice levels are multiplicative, with a gentle 10% change for every | |
882 | * nice level changed. I.e. when a CPU-bound task goes from nice 0 to | |
883 | * nice 1, it will get ~10% less CPU time than another CPU-bound task | |
884 | * that remained on nice 0. | |
885 | * | |
886 | * The "10% effect" is relative and cumulative: from _any_ nice level, | |
887 | * if you go up 1 level, it's -10% CPU usage, if you go down 1 level | |
f9153ee6 IM |
888 | * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25. |
889 | * If a task goes up by ~10% and another task goes down by ~10% then | |
890 | * the relative distance between them is ~25%.) | |
dd41f596 IM |
891 | */ |
892 | static const int prio_to_weight[40] = { | |
254753dc IM |
893 | /* -20 */ 88761, 71755, 56483, 46273, 36291, |
894 | /* -15 */ 29154, 23254, 18705, 14949, 11916, | |
895 | /* -10 */ 9548, 7620, 6100, 4904, 3906, | |
896 | /* -5 */ 3121, 2501, 1991, 1586, 1277, | |
897 | /* 0 */ 1024, 820, 655, 526, 423, | |
898 | /* 5 */ 335, 272, 215, 172, 137, | |
899 | /* 10 */ 110, 87, 70, 56, 45, | |
900 | /* 15 */ 36, 29, 23, 18, 15, | |
dd41f596 IM |
901 | }; |
902 | ||
5714d2de IM |
903 | /* |
904 | * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated. | |
905 | * | |
906 | * In cases where the weight does not change often, we can use the | |
907 | * precalculated inverse to speed up arithmetics by turning divisions | |
908 | * into multiplications: | |
909 | */ | |
dd41f596 | 910 | static const u32 prio_to_wmult[40] = { |
254753dc IM |
911 | /* -20 */ 48388, 59856, 76040, 92818, 118348, |
912 | /* -15 */ 147320, 184698, 229616, 287308, 360437, | |
913 | /* -10 */ 449829, 563644, 704093, 875809, 1099582, | |
914 | /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326, | |
915 | /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587, | |
916 | /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126, | |
917 | /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717, | |
918 | /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153, | |
dd41f596 | 919 | }; |
2dd73a4f | 920 | |
dd41f596 IM |
921 | static void activate_task(struct rq *rq, struct task_struct *p, int wakeup); |
922 | ||
923 | /* | |
924 | * runqueue iterator, to support SMP load-balancing between different | |
925 | * scheduling classes, without having to expose their internal data | |
926 | * structures to the load-balancing proper: | |
927 | */ | |
928 | struct rq_iterator { | |
929 | void *arg; | |
930 | struct task_struct *(*start)(void *); | |
931 | struct task_struct *(*next)(void *); | |
932 | }; | |
933 | ||
e1d1484f PW |
934 | #ifdef CONFIG_SMP |
935 | static unsigned long | |
936 | balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
937 | unsigned long max_load_move, struct sched_domain *sd, | |
938 | enum cpu_idle_type idle, int *all_pinned, | |
939 | int *this_best_prio, struct rq_iterator *iterator); | |
940 | ||
941 | static int | |
942 | iter_move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
943 | struct sched_domain *sd, enum cpu_idle_type idle, | |
944 | struct rq_iterator *iterator); | |
e1d1484f | 945 | #endif |
dd41f596 | 946 | |
d842de87 SV |
947 | #ifdef CONFIG_CGROUP_CPUACCT |
948 | static void cpuacct_charge(struct task_struct *tsk, u64 cputime); | |
949 | #else | |
950 | static inline void cpuacct_charge(struct task_struct *tsk, u64 cputime) {} | |
951 | #endif | |
952 | ||
58e2d4ca SV |
953 | static inline void inc_cpu_load(struct rq *rq, unsigned long load) |
954 | { | |
955 | update_load_add(&rq->load, load); | |
956 | } | |
957 | ||
958 | static inline void dec_cpu_load(struct rq *rq, unsigned long load) | |
959 | { | |
960 | update_load_sub(&rq->load, load); | |
961 | } | |
962 | ||
e7693a36 GH |
963 | #ifdef CONFIG_SMP |
964 | static unsigned long source_load(int cpu, int type); | |
965 | static unsigned long target_load(int cpu, int type); | |
966 | static unsigned long cpu_avg_load_per_task(int cpu); | |
967 | static int task_hot(struct task_struct *p, u64 now, struct sched_domain *sd); | |
968 | #endif /* CONFIG_SMP */ | |
969 | ||
dd41f596 | 970 | #include "sched_stats.h" |
dd41f596 | 971 | #include "sched_idletask.c" |
5522d5d5 IM |
972 | #include "sched_fair.c" |
973 | #include "sched_rt.c" | |
dd41f596 IM |
974 | #ifdef CONFIG_SCHED_DEBUG |
975 | # include "sched_debug.c" | |
976 | #endif | |
977 | ||
978 | #define sched_class_highest (&rt_sched_class) | |
979 | ||
e5fa2237 | 980 | static void inc_nr_running(struct task_struct *p, struct rq *rq) |
9c217245 IM |
981 | { |
982 | rq->nr_running++; | |
9c217245 IM |
983 | } |
984 | ||
db53181e | 985 | static void dec_nr_running(struct task_struct *p, struct rq *rq) |
9c217245 IM |
986 | { |
987 | rq->nr_running--; | |
9c217245 IM |
988 | } |
989 | ||
45bf76df IM |
990 | static void set_load_weight(struct task_struct *p) |
991 | { | |
992 | if (task_has_rt_policy(p)) { | |
dd41f596 IM |
993 | p->se.load.weight = prio_to_weight[0] * 2; |
994 | p->se.load.inv_weight = prio_to_wmult[0] >> 1; | |
995 | return; | |
996 | } | |
45bf76df | 997 | |
dd41f596 IM |
998 | /* |
999 | * SCHED_IDLE tasks get minimal weight: | |
1000 | */ | |
1001 | if (p->policy == SCHED_IDLE) { | |
1002 | p->se.load.weight = WEIGHT_IDLEPRIO; | |
1003 | p->se.load.inv_weight = WMULT_IDLEPRIO; | |
1004 | return; | |
1005 | } | |
71f8bd46 | 1006 | |
dd41f596 IM |
1007 | p->se.load.weight = prio_to_weight[p->static_prio - MAX_RT_PRIO]; |
1008 | p->se.load.inv_weight = prio_to_wmult[p->static_prio - MAX_RT_PRIO]; | |
71f8bd46 IM |
1009 | } |
1010 | ||
8159f87e | 1011 | static void enqueue_task(struct rq *rq, struct task_struct *p, int wakeup) |
71f8bd46 | 1012 | { |
dd41f596 | 1013 | sched_info_queued(p); |
fd390f6a | 1014 | p->sched_class->enqueue_task(rq, p, wakeup); |
dd41f596 | 1015 | p->se.on_rq = 1; |
71f8bd46 IM |
1016 | } |
1017 | ||
69be72c1 | 1018 | static void dequeue_task(struct rq *rq, struct task_struct *p, int sleep) |
71f8bd46 | 1019 | { |
f02231e5 | 1020 | p->sched_class->dequeue_task(rq, p, sleep); |
dd41f596 | 1021 | p->se.on_rq = 0; |
71f8bd46 IM |
1022 | } |
1023 | ||
14531189 | 1024 | /* |
dd41f596 | 1025 | * __normal_prio - return the priority that is based on the static prio |
14531189 | 1026 | */ |
14531189 IM |
1027 | static inline int __normal_prio(struct task_struct *p) |
1028 | { | |
dd41f596 | 1029 | return p->static_prio; |
14531189 IM |
1030 | } |
1031 | ||
b29739f9 IM |
1032 | /* |
1033 | * Calculate the expected normal priority: i.e. priority | |
1034 | * without taking RT-inheritance into account. Might be | |
1035 | * boosted by interactivity modifiers. Changes upon fork, | |
1036 | * setprio syscalls, and whenever the interactivity | |
1037 | * estimator recalculates. | |
1038 | */ | |
36c8b586 | 1039 | static inline int normal_prio(struct task_struct *p) |
b29739f9 IM |
1040 | { |
1041 | int prio; | |
1042 | ||
e05606d3 | 1043 | if (task_has_rt_policy(p)) |
b29739f9 IM |
1044 | prio = MAX_RT_PRIO-1 - p->rt_priority; |
1045 | else | |
1046 | prio = __normal_prio(p); | |
1047 | return prio; | |
1048 | } | |
1049 | ||
1050 | /* | |
1051 | * Calculate the current priority, i.e. the priority | |
1052 | * taken into account by the scheduler. This value might | |
1053 | * be boosted by RT tasks, or might be boosted by | |
1054 | * interactivity modifiers. Will be RT if the task got | |
1055 | * RT-boosted. If not then it returns p->normal_prio. | |
1056 | */ | |
36c8b586 | 1057 | static int effective_prio(struct task_struct *p) |
b29739f9 IM |
1058 | { |
1059 | p->normal_prio = normal_prio(p); | |
1060 | /* | |
1061 | * If we are RT tasks or we were boosted to RT priority, | |
1062 | * keep the priority unchanged. Otherwise, update priority | |
1063 | * to the normal priority: | |
1064 | */ | |
1065 | if (!rt_prio(p->prio)) | |
1066 | return p->normal_prio; | |
1067 | return p->prio; | |
1068 | } | |
1069 | ||
1da177e4 | 1070 | /* |
dd41f596 | 1071 | * activate_task - move a task to the runqueue. |
1da177e4 | 1072 | */ |
dd41f596 | 1073 | static void activate_task(struct rq *rq, struct task_struct *p, int wakeup) |
1da177e4 | 1074 | { |
dd41f596 IM |
1075 | if (p->state == TASK_UNINTERRUPTIBLE) |
1076 | rq->nr_uninterruptible--; | |
1da177e4 | 1077 | |
8159f87e | 1078 | enqueue_task(rq, p, wakeup); |
e5fa2237 | 1079 | inc_nr_running(p, rq); |
1da177e4 LT |
1080 | } |
1081 | ||
1da177e4 LT |
1082 | /* |
1083 | * deactivate_task - remove a task from the runqueue. | |
1084 | */ | |
2e1cb74a | 1085 | static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep) |
1da177e4 | 1086 | { |
dd41f596 IM |
1087 | if (p->state == TASK_UNINTERRUPTIBLE) |
1088 | rq->nr_uninterruptible++; | |
1089 | ||
69be72c1 | 1090 | dequeue_task(rq, p, sleep); |
db53181e | 1091 | dec_nr_running(p, rq); |
1da177e4 LT |
1092 | } |
1093 | ||
1da177e4 LT |
1094 | /** |
1095 | * task_curr - is this task currently executing on a CPU? | |
1096 | * @p: the task in question. | |
1097 | */ | |
36c8b586 | 1098 | inline int task_curr(const struct task_struct *p) |
1da177e4 LT |
1099 | { |
1100 | return cpu_curr(task_cpu(p)) == p; | |
1101 | } | |
1102 | ||
2dd73a4f PW |
1103 | /* Used instead of source_load when we know the type == 0 */ |
1104 | unsigned long weighted_cpuload(const int cpu) | |
1105 | { | |
495eca49 | 1106 | return cpu_rq(cpu)->load.weight; |
dd41f596 IM |
1107 | } |
1108 | ||
1109 | static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu) | |
1110 | { | |
ce96b5ac | 1111 | set_task_cfs_rq(p, cpu); |
dd41f596 | 1112 | #ifdef CONFIG_SMP |
ce96b5ac DA |
1113 | /* |
1114 | * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be | |
1115 | * successfuly executed on another CPU. We must ensure that updates of | |
1116 | * per-task data have been completed by this moment. | |
1117 | */ | |
1118 | smp_wmb(); | |
dd41f596 | 1119 | task_thread_info(p)->cpu = cpu; |
dd41f596 | 1120 | #endif |
2dd73a4f PW |
1121 | } |
1122 | ||
1da177e4 | 1123 | #ifdef CONFIG_SMP |
c65cc870 | 1124 | |
cc367732 IM |
1125 | /* |
1126 | * Is this task likely cache-hot: | |
1127 | */ | |
e7693a36 | 1128 | static int |
cc367732 IM |
1129 | task_hot(struct task_struct *p, u64 now, struct sched_domain *sd) |
1130 | { | |
1131 | s64 delta; | |
1132 | ||
1133 | if (p->sched_class != &fair_sched_class) | |
1134 | return 0; | |
1135 | ||
6bc1665b IM |
1136 | if (sysctl_sched_migration_cost == -1) |
1137 | return 1; | |
1138 | if (sysctl_sched_migration_cost == 0) | |
1139 | return 0; | |
1140 | ||
cc367732 IM |
1141 | delta = now - p->se.exec_start; |
1142 | ||
1143 | return delta < (s64)sysctl_sched_migration_cost; | |
1144 | } | |
1145 | ||
1146 | ||
dd41f596 | 1147 | void set_task_cpu(struct task_struct *p, unsigned int new_cpu) |
c65cc870 | 1148 | { |
dd41f596 IM |
1149 | int old_cpu = task_cpu(p); |
1150 | struct rq *old_rq = cpu_rq(old_cpu), *new_rq = cpu_rq(new_cpu); | |
2830cf8c SV |
1151 | struct cfs_rq *old_cfsrq = task_cfs_rq(p), |
1152 | *new_cfsrq = cpu_cfs_rq(old_cfsrq, new_cpu); | |
bbdba7c0 | 1153 | u64 clock_offset; |
dd41f596 IM |
1154 | |
1155 | clock_offset = old_rq->clock - new_rq->clock; | |
6cfb0d5d IM |
1156 | |
1157 | #ifdef CONFIG_SCHEDSTATS | |
1158 | if (p->se.wait_start) | |
1159 | p->se.wait_start -= clock_offset; | |
dd41f596 IM |
1160 | if (p->se.sleep_start) |
1161 | p->se.sleep_start -= clock_offset; | |
1162 | if (p->se.block_start) | |
1163 | p->se.block_start -= clock_offset; | |
cc367732 IM |
1164 | if (old_cpu != new_cpu) { |
1165 | schedstat_inc(p, se.nr_migrations); | |
1166 | if (task_hot(p, old_rq->clock, NULL)) | |
1167 | schedstat_inc(p, se.nr_forced2_migrations); | |
1168 | } | |
6cfb0d5d | 1169 | #endif |
2830cf8c SV |
1170 | p->se.vruntime -= old_cfsrq->min_vruntime - |
1171 | new_cfsrq->min_vruntime; | |
dd41f596 IM |
1172 | |
1173 | __set_task_cpu(p, new_cpu); | |
c65cc870 IM |
1174 | } |
1175 | ||
70b97a7f | 1176 | struct migration_req { |
1da177e4 | 1177 | struct list_head list; |
1da177e4 | 1178 | |
36c8b586 | 1179 | struct task_struct *task; |
1da177e4 LT |
1180 | int dest_cpu; |
1181 | ||
1da177e4 | 1182 | struct completion done; |
70b97a7f | 1183 | }; |
1da177e4 LT |
1184 | |
1185 | /* | |
1186 | * The task's runqueue lock must be held. | |
1187 | * Returns true if you have to wait for migration thread. | |
1188 | */ | |
36c8b586 | 1189 | static int |
70b97a7f | 1190 | migrate_task(struct task_struct *p, int dest_cpu, struct migration_req *req) |
1da177e4 | 1191 | { |
70b97a7f | 1192 | struct rq *rq = task_rq(p); |
1da177e4 LT |
1193 | |
1194 | /* | |
1195 | * If the task is not on a runqueue (and not running), then | |
1196 | * it is sufficient to simply update the task's cpu field. | |
1197 | */ | |
dd41f596 | 1198 | if (!p->se.on_rq && !task_running(rq, p)) { |
1da177e4 LT |
1199 | set_task_cpu(p, dest_cpu); |
1200 | return 0; | |
1201 | } | |
1202 | ||
1203 | init_completion(&req->done); | |
1da177e4 LT |
1204 | req->task = p; |
1205 | req->dest_cpu = dest_cpu; | |
1206 | list_add(&req->list, &rq->migration_queue); | |
48f24c4d | 1207 | |
1da177e4 LT |
1208 | return 1; |
1209 | } | |
1210 | ||
1211 | /* | |
1212 | * wait_task_inactive - wait for a thread to unschedule. | |
1213 | * | |
1214 | * The caller must ensure that the task *will* unschedule sometime soon, | |
1215 | * else this function might spin for a *long* time. This function can't | |
1216 | * be called with interrupts off, or it may introduce deadlock with | |
1217 | * smp_call_function() if an IPI is sent by the same process we are | |
1218 | * waiting to become inactive. | |
1219 | */ | |
36c8b586 | 1220 | void wait_task_inactive(struct task_struct *p) |
1da177e4 LT |
1221 | { |
1222 | unsigned long flags; | |
dd41f596 | 1223 | int running, on_rq; |
70b97a7f | 1224 | struct rq *rq; |
1da177e4 | 1225 | |
3a5c359a AK |
1226 | for (;;) { |
1227 | /* | |
1228 | * We do the initial early heuristics without holding | |
1229 | * any task-queue locks at all. We'll only try to get | |
1230 | * the runqueue lock when things look like they will | |
1231 | * work out! | |
1232 | */ | |
1233 | rq = task_rq(p); | |
fa490cfd | 1234 | |
3a5c359a AK |
1235 | /* |
1236 | * If the task is actively running on another CPU | |
1237 | * still, just relax and busy-wait without holding | |
1238 | * any locks. | |
1239 | * | |
1240 | * NOTE! Since we don't hold any locks, it's not | |
1241 | * even sure that "rq" stays as the right runqueue! | |
1242 | * But we don't care, since "task_running()" will | |
1243 | * return false if the runqueue has changed and p | |
1244 | * is actually now running somewhere else! | |
1245 | */ | |
1246 | while (task_running(rq, p)) | |
1247 | cpu_relax(); | |
fa490cfd | 1248 | |
3a5c359a AK |
1249 | /* |
1250 | * Ok, time to look more closely! We need the rq | |
1251 | * lock now, to be *sure*. If we're wrong, we'll | |
1252 | * just go back and repeat. | |
1253 | */ | |
1254 | rq = task_rq_lock(p, &flags); | |
1255 | running = task_running(rq, p); | |
1256 | on_rq = p->se.on_rq; | |
1257 | task_rq_unlock(rq, &flags); | |
fa490cfd | 1258 | |
3a5c359a AK |
1259 | /* |
1260 | * Was it really running after all now that we | |
1261 | * checked with the proper locks actually held? | |
1262 | * | |
1263 | * Oops. Go back and try again.. | |
1264 | */ | |
1265 | if (unlikely(running)) { | |
1266 | cpu_relax(); | |
1267 | continue; | |
1268 | } | |
fa490cfd | 1269 | |
3a5c359a AK |
1270 | /* |
1271 | * It's not enough that it's not actively running, | |
1272 | * it must be off the runqueue _entirely_, and not | |
1273 | * preempted! | |
1274 | * | |
1275 | * So if it wa still runnable (but just not actively | |
1276 | * running right now), it's preempted, and we should | |
1277 | * yield - it could be a while. | |
1278 | */ | |
1279 | if (unlikely(on_rq)) { | |
1280 | schedule_timeout_uninterruptible(1); | |
1281 | continue; | |
1282 | } | |
fa490cfd | 1283 | |
3a5c359a AK |
1284 | /* |
1285 | * Ahh, all good. It wasn't running, and it wasn't | |
1286 | * runnable, which means that it will never become | |
1287 | * running in the future either. We're all done! | |
1288 | */ | |
1289 | break; | |
1290 | } | |
1da177e4 LT |
1291 | } |
1292 | ||
1293 | /*** | |
1294 | * kick_process - kick a running thread to enter/exit the kernel | |
1295 | * @p: the to-be-kicked thread | |
1296 | * | |
1297 | * Cause a process which is running on another CPU to enter | |
1298 | * kernel-mode, without any delay. (to get signals handled.) | |
1299 | * | |
1300 | * NOTE: this function doesnt have to take the runqueue lock, | |
1301 | * because all it wants to ensure is that the remote task enters | |
1302 | * the kernel. If the IPI races and the task has been migrated | |
1303 | * to another CPU then no harm is done and the purpose has been | |
1304 | * achieved as well. | |
1305 | */ | |
36c8b586 | 1306 | void kick_process(struct task_struct *p) |
1da177e4 LT |
1307 | { |
1308 | int cpu; | |
1309 | ||
1310 | preempt_disable(); | |
1311 | cpu = task_cpu(p); | |
1312 | if ((cpu != smp_processor_id()) && task_curr(p)) | |
1313 | smp_send_reschedule(cpu); | |
1314 | preempt_enable(); | |
1315 | } | |
1316 | ||
1317 | /* | |
2dd73a4f PW |
1318 | * Return a low guess at the load of a migration-source cpu weighted |
1319 | * according to the scheduling class and "nice" value. | |
1da177e4 LT |
1320 | * |
1321 | * We want to under-estimate the load of migration sources, to | |
1322 | * balance conservatively. | |
1323 | */ | |
a9957449 | 1324 | static unsigned long source_load(int cpu, int type) |
1da177e4 | 1325 | { |
70b97a7f | 1326 | struct rq *rq = cpu_rq(cpu); |
dd41f596 | 1327 | unsigned long total = weighted_cpuload(cpu); |
2dd73a4f | 1328 | |
3b0bd9bc | 1329 | if (type == 0) |
dd41f596 | 1330 | return total; |
b910472d | 1331 | |
dd41f596 | 1332 | return min(rq->cpu_load[type-1], total); |
1da177e4 LT |
1333 | } |
1334 | ||
1335 | /* | |
2dd73a4f PW |
1336 | * Return a high guess at the load of a migration-target cpu weighted |
1337 | * according to the scheduling class and "nice" value. | |
1da177e4 | 1338 | */ |
a9957449 | 1339 | static unsigned long target_load(int cpu, int type) |
1da177e4 | 1340 | { |
70b97a7f | 1341 | struct rq *rq = cpu_rq(cpu); |
dd41f596 | 1342 | unsigned long total = weighted_cpuload(cpu); |
2dd73a4f | 1343 | |
7897986b | 1344 | if (type == 0) |
dd41f596 | 1345 | return total; |
3b0bd9bc | 1346 | |
dd41f596 | 1347 | return max(rq->cpu_load[type-1], total); |
2dd73a4f PW |
1348 | } |
1349 | ||
1350 | /* | |
1351 | * Return the average load per task on the cpu's run queue | |
1352 | */ | |
e7693a36 | 1353 | static unsigned long cpu_avg_load_per_task(int cpu) |
2dd73a4f | 1354 | { |
70b97a7f | 1355 | struct rq *rq = cpu_rq(cpu); |
dd41f596 | 1356 | unsigned long total = weighted_cpuload(cpu); |
2dd73a4f PW |
1357 | unsigned long n = rq->nr_running; |
1358 | ||
dd41f596 | 1359 | return n ? total / n : SCHED_LOAD_SCALE; |
1da177e4 LT |
1360 | } |
1361 | ||
147cbb4b NP |
1362 | /* |
1363 | * find_idlest_group finds and returns the least busy CPU group within the | |
1364 | * domain. | |
1365 | */ | |
1366 | static struct sched_group * | |
1367 | find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu) | |
1368 | { | |
1369 | struct sched_group *idlest = NULL, *this = NULL, *group = sd->groups; | |
1370 | unsigned long min_load = ULONG_MAX, this_load = 0; | |
1371 | int load_idx = sd->forkexec_idx; | |
1372 | int imbalance = 100 + (sd->imbalance_pct-100)/2; | |
1373 | ||
1374 | do { | |
1375 | unsigned long load, avg_load; | |
1376 | int local_group; | |
1377 | int i; | |
1378 | ||
da5a5522 BD |
1379 | /* Skip over this group if it has no CPUs allowed */ |
1380 | if (!cpus_intersects(group->cpumask, p->cpus_allowed)) | |
3a5c359a | 1381 | continue; |
da5a5522 | 1382 | |
147cbb4b | 1383 | local_group = cpu_isset(this_cpu, group->cpumask); |
147cbb4b NP |
1384 | |
1385 | /* Tally up the load of all CPUs in the group */ | |
1386 | avg_load = 0; | |
1387 | ||
1388 | for_each_cpu_mask(i, group->cpumask) { | |
1389 | /* Bias balancing toward cpus of our domain */ | |
1390 | if (local_group) | |
1391 | load = source_load(i, load_idx); | |
1392 | else | |
1393 | load = target_load(i, load_idx); | |
1394 | ||
1395 | avg_load += load; | |
1396 | } | |
1397 | ||
1398 | /* Adjust by relative CPU power of the group */ | |
5517d86b ED |
1399 | avg_load = sg_div_cpu_power(group, |
1400 | avg_load * SCHED_LOAD_SCALE); | |
147cbb4b NP |
1401 | |
1402 | if (local_group) { | |
1403 | this_load = avg_load; | |
1404 | this = group; | |
1405 | } else if (avg_load < min_load) { | |
1406 | min_load = avg_load; | |
1407 | idlest = group; | |
1408 | } | |
3a5c359a | 1409 | } while (group = group->next, group != sd->groups); |
147cbb4b NP |
1410 | |
1411 | if (!idlest || 100*this_load < imbalance*min_load) | |
1412 | return NULL; | |
1413 | return idlest; | |
1414 | } | |
1415 | ||
1416 | /* | |
0feaece9 | 1417 | * find_idlest_cpu - find the idlest cpu among the cpus in group. |
147cbb4b | 1418 | */ |
95cdf3b7 IM |
1419 | static int |
1420 | find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu) | |
147cbb4b | 1421 | { |
da5a5522 | 1422 | cpumask_t tmp; |
147cbb4b NP |
1423 | unsigned long load, min_load = ULONG_MAX; |
1424 | int idlest = -1; | |
1425 | int i; | |
1426 | ||
da5a5522 BD |
1427 | /* Traverse only the allowed CPUs */ |
1428 | cpus_and(tmp, group->cpumask, p->cpus_allowed); | |
1429 | ||
1430 | for_each_cpu_mask(i, tmp) { | |
2dd73a4f | 1431 | load = weighted_cpuload(i); |
147cbb4b NP |
1432 | |
1433 | if (load < min_load || (load == min_load && i == this_cpu)) { | |
1434 | min_load = load; | |
1435 | idlest = i; | |
1436 | } | |
1437 | } | |
1438 | ||
1439 | return idlest; | |
1440 | } | |
1441 | ||
476d139c NP |
1442 | /* |
1443 | * sched_balance_self: balance the current task (running on cpu) in domains | |
1444 | * that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and | |
1445 | * SD_BALANCE_EXEC. | |
1446 | * | |
1447 | * Balance, ie. select the least loaded group. | |
1448 | * | |
1449 | * Returns the target CPU number, or the same CPU if no balancing is needed. | |
1450 | * | |
1451 | * preempt must be disabled. | |
1452 | */ | |
1453 | static int sched_balance_self(int cpu, int flag) | |
1454 | { | |
1455 | struct task_struct *t = current; | |
1456 | struct sched_domain *tmp, *sd = NULL; | |
147cbb4b | 1457 | |
c96d145e | 1458 | for_each_domain(cpu, tmp) { |
9761eea8 IM |
1459 | /* |
1460 | * If power savings logic is enabled for a domain, stop there. | |
1461 | */ | |
5c45bf27 SS |
1462 | if (tmp->flags & SD_POWERSAVINGS_BALANCE) |
1463 | break; | |
476d139c NP |
1464 | if (tmp->flags & flag) |
1465 | sd = tmp; | |
c96d145e | 1466 | } |
476d139c NP |
1467 | |
1468 | while (sd) { | |
1469 | cpumask_t span; | |
1470 | struct sched_group *group; | |
1a848870 SS |
1471 | int new_cpu, weight; |
1472 | ||
1473 | if (!(sd->flags & flag)) { | |
1474 | sd = sd->child; | |
1475 | continue; | |
1476 | } | |
476d139c NP |
1477 | |
1478 | span = sd->span; | |
1479 | group = find_idlest_group(sd, t, cpu); | |
1a848870 SS |
1480 | if (!group) { |
1481 | sd = sd->child; | |
1482 | continue; | |
1483 | } | |
476d139c | 1484 | |
da5a5522 | 1485 | new_cpu = find_idlest_cpu(group, t, cpu); |
1a848870 SS |
1486 | if (new_cpu == -1 || new_cpu == cpu) { |
1487 | /* Now try balancing at a lower domain level of cpu */ | |
1488 | sd = sd->child; | |
1489 | continue; | |
1490 | } | |
476d139c | 1491 | |
1a848870 | 1492 | /* Now try balancing at a lower domain level of new_cpu */ |
476d139c | 1493 | cpu = new_cpu; |
476d139c NP |
1494 | sd = NULL; |
1495 | weight = cpus_weight(span); | |
1496 | for_each_domain(cpu, tmp) { | |
1497 | if (weight <= cpus_weight(tmp->span)) | |
1498 | break; | |
1499 | if (tmp->flags & flag) | |
1500 | sd = tmp; | |
1501 | } | |
1502 | /* while loop will break here if sd == NULL */ | |
1503 | } | |
1504 | ||
1505 | return cpu; | |
1506 | } | |
1507 | ||
1508 | #endif /* CONFIG_SMP */ | |
1da177e4 | 1509 | |
1da177e4 LT |
1510 | /*** |
1511 | * try_to_wake_up - wake up a thread | |
1512 | * @p: the to-be-woken-up thread | |
1513 | * @state: the mask of task states that can be woken | |
1514 | * @sync: do a synchronous wakeup? | |
1515 | * | |
1516 | * Put it on the run-queue if it's not already there. The "current" | |
1517 | * thread is always on the run-queue (except when the actual | |
1518 | * re-schedule is in progress), and as such you're allowed to do | |
1519 | * the simpler "current->state = TASK_RUNNING" to mark yourself | |
1520 | * runnable without the overhead of this. | |
1521 | * | |
1522 | * returns failure only if the task is already active. | |
1523 | */ | |
36c8b586 | 1524 | static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync) |
1da177e4 | 1525 | { |
cc367732 | 1526 | int cpu, orig_cpu, this_cpu, success = 0; |
1da177e4 LT |
1527 | unsigned long flags; |
1528 | long old_state; | |
70b97a7f | 1529 | struct rq *rq; |
1da177e4 | 1530 | #ifdef CONFIG_SMP |
1da177e4 LT |
1531 | int new_cpu; |
1532 | #endif | |
1533 | ||
1534 | rq = task_rq_lock(p, &flags); | |
1535 | old_state = p->state; | |
1536 | if (!(old_state & state)) | |
1537 | goto out; | |
1538 | ||
dd41f596 | 1539 | if (p->se.on_rq) |
1da177e4 LT |
1540 | goto out_running; |
1541 | ||
1542 | cpu = task_cpu(p); | |
cc367732 | 1543 | orig_cpu = cpu; |
1da177e4 LT |
1544 | this_cpu = smp_processor_id(); |
1545 | ||
1546 | #ifdef CONFIG_SMP | |
1547 | if (unlikely(task_running(rq, p))) | |
1548 | goto out_activate; | |
1549 | ||
e7693a36 | 1550 | new_cpu = p->sched_class->select_task_rq(p, sync); |
1da177e4 LT |
1551 | if (new_cpu != cpu) { |
1552 | set_task_cpu(p, new_cpu); | |
1553 | task_rq_unlock(rq, &flags); | |
1554 | /* might preempt at this point */ | |
1555 | rq = task_rq_lock(p, &flags); | |
1556 | old_state = p->state; | |
1557 | if (!(old_state & state)) | |
1558 | goto out; | |
dd41f596 | 1559 | if (p->se.on_rq) |
1da177e4 LT |
1560 | goto out_running; |
1561 | ||
1562 | this_cpu = smp_processor_id(); | |
1563 | cpu = task_cpu(p); | |
1564 | } | |
1565 | ||
e7693a36 GH |
1566 | #ifdef CONFIG_SCHEDSTATS |
1567 | schedstat_inc(rq, ttwu_count); | |
1568 | if (cpu == this_cpu) | |
1569 | schedstat_inc(rq, ttwu_local); | |
1570 | else { | |
1571 | struct sched_domain *sd; | |
1572 | for_each_domain(this_cpu, sd) { | |
1573 | if (cpu_isset(cpu, sd->span)) { | |
1574 | schedstat_inc(sd, ttwu_wake_remote); | |
1575 | break; | |
1576 | } | |
1577 | } | |
1578 | } | |
1579 | ||
1580 | #endif | |
1581 | ||
1582 | ||
1da177e4 LT |
1583 | out_activate: |
1584 | #endif /* CONFIG_SMP */ | |
cc367732 IM |
1585 | schedstat_inc(p, se.nr_wakeups); |
1586 | if (sync) | |
1587 | schedstat_inc(p, se.nr_wakeups_sync); | |
1588 | if (orig_cpu != cpu) | |
1589 | schedstat_inc(p, se.nr_wakeups_migrate); | |
1590 | if (cpu == this_cpu) | |
1591 | schedstat_inc(p, se.nr_wakeups_local); | |
1592 | else | |
1593 | schedstat_inc(p, se.nr_wakeups_remote); | |
2daa3577 | 1594 | update_rq_clock(rq); |
dd41f596 | 1595 | activate_task(rq, p, 1); |
9c63d9c0 | 1596 | check_preempt_curr(rq, p); |
1da177e4 LT |
1597 | success = 1; |
1598 | ||
1599 | out_running: | |
1600 | p->state = TASK_RUNNING; | |
4642dafd | 1601 | wakeup_balance_rt(rq, p); |
1da177e4 LT |
1602 | out: |
1603 | task_rq_unlock(rq, &flags); | |
1604 | ||
1605 | return success; | |
1606 | } | |
1607 | ||
36c8b586 | 1608 | int fastcall wake_up_process(struct task_struct *p) |
1da177e4 LT |
1609 | { |
1610 | return try_to_wake_up(p, TASK_STOPPED | TASK_TRACED | | |
1611 | TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE, 0); | |
1612 | } | |
1da177e4 LT |
1613 | EXPORT_SYMBOL(wake_up_process); |
1614 | ||
36c8b586 | 1615 | int fastcall wake_up_state(struct task_struct *p, unsigned int state) |
1da177e4 LT |
1616 | { |
1617 | return try_to_wake_up(p, state, 0); | |
1618 | } | |
1619 | ||
1da177e4 LT |
1620 | /* |
1621 | * Perform scheduler related setup for a newly forked process p. | |
1622 | * p is forked by current. | |
dd41f596 IM |
1623 | * |
1624 | * __sched_fork() is basic setup used by init_idle() too: | |
1625 | */ | |
1626 | static void __sched_fork(struct task_struct *p) | |
1627 | { | |
dd41f596 IM |
1628 | p->se.exec_start = 0; |
1629 | p->se.sum_exec_runtime = 0; | |
f6cf891c | 1630 | p->se.prev_sum_exec_runtime = 0; |
6cfb0d5d IM |
1631 | |
1632 | #ifdef CONFIG_SCHEDSTATS | |
1633 | p->se.wait_start = 0; | |
dd41f596 IM |
1634 | p->se.sum_sleep_runtime = 0; |
1635 | p->se.sleep_start = 0; | |
dd41f596 IM |
1636 | p->se.block_start = 0; |
1637 | p->se.sleep_max = 0; | |
1638 | p->se.block_max = 0; | |
1639 | p->se.exec_max = 0; | |
eba1ed4b | 1640 | p->se.slice_max = 0; |
dd41f596 | 1641 | p->se.wait_max = 0; |
6cfb0d5d | 1642 | #endif |
476d139c | 1643 | |
dd41f596 IM |
1644 | INIT_LIST_HEAD(&p->run_list); |
1645 | p->se.on_rq = 0; | |
476d139c | 1646 | |
e107be36 AK |
1647 | #ifdef CONFIG_PREEMPT_NOTIFIERS |
1648 | INIT_HLIST_HEAD(&p->preempt_notifiers); | |
1649 | #endif | |
1650 | ||
1da177e4 LT |
1651 | /* |
1652 | * We mark the process as running here, but have not actually | |
1653 | * inserted it onto the runqueue yet. This guarantees that | |
1654 | * nobody will actually run it, and a signal or other external | |
1655 | * event cannot wake it up and insert it on the runqueue either. | |
1656 | */ | |
1657 | p->state = TASK_RUNNING; | |
dd41f596 IM |
1658 | } |
1659 | ||
1660 | /* | |
1661 | * fork()/clone()-time setup: | |
1662 | */ | |
1663 | void sched_fork(struct task_struct *p, int clone_flags) | |
1664 | { | |
1665 | int cpu = get_cpu(); | |
1666 | ||
1667 | __sched_fork(p); | |
1668 | ||
1669 | #ifdef CONFIG_SMP | |
1670 | cpu = sched_balance_self(cpu, SD_BALANCE_FORK); | |
1671 | #endif | |
02e4bac2 | 1672 | set_task_cpu(p, cpu); |
b29739f9 IM |
1673 | |
1674 | /* | |
1675 | * Make sure we do not leak PI boosting priority to the child: | |
1676 | */ | |
1677 | p->prio = current->normal_prio; | |
2ddbf952 HS |
1678 | if (!rt_prio(p->prio)) |
1679 | p->sched_class = &fair_sched_class; | |
b29739f9 | 1680 | |
52f17b6c | 1681 | #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) |
dd41f596 | 1682 | if (likely(sched_info_on())) |
52f17b6c | 1683 | memset(&p->sched_info, 0, sizeof(p->sched_info)); |
1da177e4 | 1684 | #endif |
d6077cb8 | 1685 | #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW) |
4866cde0 NP |
1686 | p->oncpu = 0; |
1687 | #endif | |
1da177e4 | 1688 | #ifdef CONFIG_PREEMPT |
4866cde0 | 1689 | /* Want to start with kernel preemption disabled. */ |
a1261f54 | 1690 | task_thread_info(p)->preempt_count = 1; |
1da177e4 | 1691 | #endif |
476d139c | 1692 | put_cpu(); |
1da177e4 LT |
1693 | } |
1694 | ||
1695 | /* | |
1696 | * wake_up_new_task - wake up a newly created task for the first time. | |
1697 | * | |
1698 | * This function will do some initial scheduler statistics housekeeping | |
1699 | * that must be done for every newly created context, then puts the task | |
1700 | * on the runqueue and wakes it. | |
1701 | */ | |
36c8b586 | 1702 | void fastcall wake_up_new_task(struct task_struct *p, unsigned long clone_flags) |
1da177e4 LT |
1703 | { |
1704 | unsigned long flags; | |
dd41f596 | 1705 | struct rq *rq; |
1da177e4 LT |
1706 | |
1707 | rq = task_rq_lock(p, &flags); | |
147cbb4b | 1708 | BUG_ON(p->state != TASK_RUNNING); |
a8e504d2 | 1709 | update_rq_clock(rq); |
1da177e4 LT |
1710 | |
1711 | p->prio = effective_prio(p); | |
1712 | ||
b9dca1e0 | 1713 | if (!p->sched_class->task_new || !current->se.on_rq) { |
dd41f596 | 1714 | activate_task(rq, p, 0); |
1da177e4 | 1715 | } else { |
1da177e4 | 1716 | /* |
dd41f596 IM |
1717 | * Let the scheduling class do new task startup |
1718 | * management (if any): | |
1da177e4 | 1719 | */ |
ee0827d8 | 1720 | p->sched_class->task_new(rq, p); |
e5fa2237 | 1721 | inc_nr_running(p, rq); |
1da177e4 | 1722 | } |
dd41f596 IM |
1723 | check_preempt_curr(rq, p); |
1724 | task_rq_unlock(rq, &flags); | |
1da177e4 LT |
1725 | } |
1726 | ||
e107be36 AK |
1727 | #ifdef CONFIG_PREEMPT_NOTIFIERS |
1728 | ||
1729 | /** | |
421cee29 RD |
1730 | * preempt_notifier_register - tell me when current is being being preempted & rescheduled |
1731 | * @notifier: notifier struct to register | |
e107be36 AK |
1732 | */ |
1733 | void preempt_notifier_register(struct preempt_notifier *notifier) | |
1734 | { | |
1735 | hlist_add_head(¬ifier->link, ¤t->preempt_notifiers); | |
1736 | } | |
1737 | EXPORT_SYMBOL_GPL(preempt_notifier_register); | |
1738 | ||
1739 | /** | |
1740 | * preempt_notifier_unregister - no longer interested in preemption notifications | |
421cee29 | 1741 | * @notifier: notifier struct to unregister |
e107be36 AK |
1742 | * |
1743 | * This is safe to call from within a preemption notifier. | |
1744 | */ | |
1745 | void preempt_notifier_unregister(struct preempt_notifier *notifier) | |
1746 | { | |
1747 | hlist_del(¬ifier->link); | |
1748 | } | |
1749 | EXPORT_SYMBOL_GPL(preempt_notifier_unregister); | |
1750 | ||
1751 | static void fire_sched_in_preempt_notifiers(struct task_struct *curr) | |
1752 | { | |
1753 | struct preempt_notifier *notifier; | |
1754 | struct hlist_node *node; | |
1755 | ||
1756 | hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link) | |
1757 | notifier->ops->sched_in(notifier, raw_smp_processor_id()); | |
1758 | } | |
1759 | ||
1760 | static void | |
1761 | fire_sched_out_preempt_notifiers(struct task_struct *curr, | |
1762 | struct task_struct *next) | |
1763 | { | |
1764 | struct preempt_notifier *notifier; | |
1765 | struct hlist_node *node; | |
1766 | ||
1767 | hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link) | |
1768 | notifier->ops->sched_out(notifier, next); | |
1769 | } | |
1770 | ||
1771 | #else | |
1772 | ||
1773 | static void fire_sched_in_preempt_notifiers(struct task_struct *curr) | |
1774 | { | |
1775 | } | |
1776 | ||
1777 | static void | |
1778 | fire_sched_out_preempt_notifiers(struct task_struct *curr, | |
1779 | struct task_struct *next) | |
1780 | { | |
1781 | } | |
1782 | ||
1783 | #endif | |
1784 | ||
4866cde0 NP |
1785 | /** |
1786 | * prepare_task_switch - prepare to switch tasks | |
1787 | * @rq: the runqueue preparing to switch | |
421cee29 | 1788 | * @prev: the current task that is being switched out |
4866cde0 NP |
1789 | * @next: the task we are going to switch to. |
1790 | * | |
1791 | * This is called with the rq lock held and interrupts off. It must | |
1792 | * be paired with a subsequent finish_task_switch after the context | |
1793 | * switch. | |
1794 | * | |
1795 | * prepare_task_switch sets up locking and calls architecture specific | |
1796 | * hooks. | |
1797 | */ | |
e107be36 AK |
1798 | static inline void |
1799 | prepare_task_switch(struct rq *rq, struct task_struct *prev, | |
1800 | struct task_struct *next) | |
4866cde0 | 1801 | { |
e107be36 | 1802 | fire_sched_out_preempt_notifiers(prev, next); |
4866cde0 NP |
1803 | prepare_lock_switch(rq, next); |
1804 | prepare_arch_switch(next); | |
1805 | } | |
1806 | ||
1da177e4 LT |
1807 | /** |
1808 | * finish_task_switch - clean up after a task-switch | |
344babaa | 1809 | * @rq: runqueue associated with task-switch |
1da177e4 LT |
1810 | * @prev: the thread we just switched away from. |
1811 | * | |
4866cde0 NP |
1812 | * finish_task_switch must be called after the context switch, paired |
1813 | * with a prepare_task_switch call before the context switch. | |
1814 | * finish_task_switch will reconcile locking set up by prepare_task_switch, | |
1815 | * and do any other architecture-specific cleanup actions. | |
1da177e4 LT |
1816 | * |
1817 | * Note that we may have delayed dropping an mm in context_switch(). If | |
41a2d6cf | 1818 | * so, we finish that here outside of the runqueue lock. (Doing it |
1da177e4 LT |
1819 | * with the lock held can cause deadlocks; see schedule() for |
1820 | * details.) | |
1821 | */ | |
a9957449 | 1822 | static void finish_task_switch(struct rq *rq, struct task_struct *prev) |
1da177e4 LT |
1823 | __releases(rq->lock) |
1824 | { | |
1da177e4 | 1825 | struct mm_struct *mm = rq->prev_mm; |
55a101f8 | 1826 | long prev_state; |
1da177e4 LT |
1827 | |
1828 | rq->prev_mm = NULL; | |
1829 | ||
1830 | /* | |
1831 | * A task struct has one reference for the use as "current". | |
c394cc9f | 1832 | * If a task dies, then it sets TASK_DEAD in tsk->state and calls |
55a101f8 ON |
1833 | * schedule one last time. The schedule call will never return, and |
1834 | * the scheduled task must drop that reference. | |
c394cc9f | 1835 | * The test for TASK_DEAD must occur while the runqueue locks are |
1da177e4 LT |
1836 | * still held, otherwise prev could be scheduled on another cpu, die |
1837 | * there before we look at prev->state, and then the reference would | |
1838 | * be dropped twice. | |
1839 | * Manfred Spraul <manfred@colorfullife.com> | |
1840 | */ | |
55a101f8 | 1841 | prev_state = prev->state; |
4866cde0 NP |
1842 | finish_arch_switch(prev); |
1843 | finish_lock_switch(rq, prev); | |
e8fa1362 SR |
1844 | schedule_tail_balance_rt(rq); |
1845 | ||
e107be36 | 1846 | fire_sched_in_preempt_notifiers(current); |
1da177e4 LT |
1847 | if (mm) |
1848 | mmdrop(mm); | |
c394cc9f | 1849 | if (unlikely(prev_state == TASK_DEAD)) { |
c6fd91f0 | 1850 | /* |
1851 | * Remove function-return probe instances associated with this | |
1852 | * task and put them back on the free list. | |
9761eea8 | 1853 | */ |
c6fd91f0 | 1854 | kprobe_flush_task(prev); |
1da177e4 | 1855 | put_task_struct(prev); |
c6fd91f0 | 1856 | } |
1da177e4 LT |
1857 | } |
1858 | ||
1859 | /** | |
1860 | * schedule_tail - first thing a freshly forked thread must call. | |
1861 | * @prev: the thread we just switched away from. | |
1862 | */ | |
36c8b586 | 1863 | asmlinkage void schedule_tail(struct task_struct *prev) |
1da177e4 LT |
1864 | __releases(rq->lock) |
1865 | { | |
70b97a7f IM |
1866 | struct rq *rq = this_rq(); |
1867 | ||
4866cde0 NP |
1868 | finish_task_switch(rq, prev); |
1869 | #ifdef __ARCH_WANT_UNLOCKED_CTXSW | |
1870 | /* In this case, finish_task_switch does not reenable preemption */ | |
1871 | preempt_enable(); | |
1872 | #endif | |
1da177e4 | 1873 | if (current->set_child_tid) |
b488893a | 1874 | put_user(task_pid_vnr(current), current->set_child_tid); |
1da177e4 LT |
1875 | } |
1876 | ||
1877 | /* | |
1878 | * context_switch - switch to the new MM and the new | |
1879 | * thread's register state. | |
1880 | */ | |
dd41f596 | 1881 | static inline void |
70b97a7f | 1882 | context_switch(struct rq *rq, struct task_struct *prev, |
36c8b586 | 1883 | struct task_struct *next) |
1da177e4 | 1884 | { |
dd41f596 | 1885 | struct mm_struct *mm, *oldmm; |
1da177e4 | 1886 | |
e107be36 | 1887 | prepare_task_switch(rq, prev, next); |
dd41f596 IM |
1888 | mm = next->mm; |
1889 | oldmm = prev->active_mm; | |
9226d125 ZA |
1890 | /* |
1891 | * For paravirt, this is coupled with an exit in switch_to to | |
1892 | * combine the page table reload and the switch backend into | |
1893 | * one hypercall. | |
1894 | */ | |
1895 | arch_enter_lazy_cpu_mode(); | |
1896 | ||
dd41f596 | 1897 | if (unlikely(!mm)) { |
1da177e4 LT |
1898 | next->active_mm = oldmm; |
1899 | atomic_inc(&oldmm->mm_count); | |
1900 | enter_lazy_tlb(oldmm, next); | |
1901 | } else | |
1902 | switch_mm(oldmm, mm, next); | |
1903 | ||
dd41f596 | 1904 | if (unlikely(!prev->mm)) { |
1da177e4 | 1905 | prev->active_mm = NULL; |
1da177e4 LT |
1906 | rq->prev_mm = oldmm; |
1907 | } | |
3a5f5e48 IM |
1908 | /* |
1909 | * Since the runqueue lock will be released by the next | |
1910 | * task (which is an invalid locking op but in the case | |
1911 | * of the scheduler it's an obvious special-case), so we | |
1912 | * do an early lockdep release here: | |
1913 | */ | |
1914 | #ifndef __ARCH_WANT_UNLOCKED_CTXSW | |
8a25d5de | 1915 | spin_release(&rq->lock.dep_map, 1, _THIS_IP_); |
3a5f5e48 | 1916 | #endif |
1da177e4 LT |
1917 | |
1918 | /* Here we just switch the register state and the stack. */ | |
1919 | switch_to(prev, next, prev); | |
1920 | ||
dd41f596 IM |
1921 | barrier(); |
1922 | /* | |
1923 | * this_rq must be evaluated again because prev may have moved | |
1924 | * CPUs since it called schedule(), thus the 'rq' on its stack | |
1925 | * frame will be invalid. | |
1926 | */ | |
1927 | finish_task_switch(this_rq(), prev); | |
1da177e4 LT |
1928 | } |
1929 | ||
1930 | /* | |
1931 | * nr_running, nr_uninterruptible and nr_context_switches: | |
1932 | * | |
1933 | * externally visible scheduler statistics: current number of runnable | |
1934 | * threads, current number of uninterruptible-sleeping threads, total | |
1935 | * number of context switches performed since bootup. | |
1936 | */ | |
1937 | unsigned long nr_running(void) | |
1938 | { | |
1939 | unsigned long i, sum = 0; | |
1940 | ||
1941 | for_each_online_cpu(i) | |
1942 | sum += cpu_rq(i)->nr_running; | |
1943 | ||
1944 | return sum; | |
1945 | } | |
1946 | ||
1947 | unsigned long nr_uninterruptible(void) | |
1948 | { | |
1949 | unsigned long i, sum = 0; | |
1950 | ||
0a945022 | 1951 | for_each_possible_cpu(i) |
1da177e4 LT |
1952 | sum += cpu_rq(i)->nr_uninterruptible; |
1953 | ||
1954 | /* | |
1955 | * Since we read the counters lockless, it might be slightly | |
1956 | * inaccurate. Do not allow it to go below zero though: | |
1957 | */ | |
1958 | if (unlikely((long)sum < 0)) | |
1959 | sum = 0; | |
1960 | ||
1961 | return sum; | |
1962 | } | |
1963 | ||
1964 | unsigned long long nr_context_switches(void) | |
1965 | { | |
cc94abfc SR |
1966 | int i; |
1967 | unsigned long long sum = 0; | |
1da177e4 | 1968 | |
0a945022 | 1969 | for_each_possible_cpu(i) |
1da177e4 LT |
1970 | sum += cpu_rq(i)->nr_switches; |
1971 | ||
1972 | return sum; | |
1973 | } | |
1974 | ||
1975 | unsigned long nr_iowait(void) | |
1976 | { | |
1977 | unsigned long i, sum = 0; | |
1978 | ||
0a945022 | 1979 | for_each_possible_cpu(i) |
1da177e4 LT |
1980 | sum += atomic_read(&cpu_rq(i)->nr_iowait); |
1981 | ||
1982 | return sum; | |
1983 | } | |
1984 | ||
db1b1fef JS |
1985 | unsigned long nr_active(void) |
1986 | { | |
1987 | unsigned long i, running = 0, uninterruptible = 0; | |
1988 | ||
1989 | for_each_online_cpu(i) { | |
1990 | running += cpu_rq(i)->nr_running; | |
1991 | uninterruptible += cpu_rq(i)->nr_uninterruptible; | |
1992 | } | |
1993 | ||
1994 | if (unlikely((long)uninterruptible < 0)) | |
1995 | uninterruptible = 0; | |
1996 | ||
1997 | return running + uninterruptible; | |
1998 | } | |
1999 | ||
48f24c4d | 2000 | /* |
dd41f596 IM |
2001 | * Update rq->cpu_load[] statistics. This function is usually called every |
2002 | * scheduler tick (TICK_NSEC). | |
48f24c4d | 2003 | */ |
dd41f596 | 2004 | static void update_cpu_load(struct rq *this_rq) |
48f24c4d | 2005 | { |
495eca49 | 2006 | unsigned long this_load = this_rq->load.weight; |
dd41f596 IM |
2007 | int i, scale; |
2008 | ||
2009 | this_rq->nr_load_updates++; | |
dd41f596 IM |
2010 | |
2011 | /* Update our load: */ | |
2012 | for (i = 0, scale = 1; i < CPU_LOAD_IDX_MAX; i++, scale += scale) { | |
2013 | unsigned long old_load, new_load; | |
2014 | ||
2015 | /* scale is effectively 1 << i now, and >> i divides by scale */ | |
2016 | ||
2017 | old_load = this_rq->cpu_load[i]; | |
2018 | new_load = this_load; | |
a25707f3 IM |
2019 | /* |
2020 | * Round up the averaging division if load is increasing. This | |
2021 | * prevents us from getting stuck on 9 if the load is 10, for | |
2022 | * example. | |
2023 | */ | |
2024 | if (new_load > old_load) | |
2025 | new_load += scale-1; | |
dd41f596 IM |
2026 | this_rq->cpu_load[i] = (old_load*(scale-1) + new_load) >> i; |
2027 | } | |
48f24c4d IM |
2028 | } |
2029 | ||
dd41f596 IM |
2030 | #ifdef CONFIG_SMP |
2031 | ||
1da177e4 LT |
2032 | /* |
2033 | * double_rq_lock - safely lock two runqueues | |
2034 | * | |
2035 | * Note this does not disable interrupts like task_rq_lock, | |
2036 | * you need to do so manually before calling. | |
2037 | */ | |
70b97a7f | 2038 | static void double_rq_lock(struct rq *rq1, struct rq *rq2) |
1da177e4 LT |
2039 | __acquires(rq1->lock) |
2040 | __acquires(rq2->lock) | |
2041 | { | |
054b9108 | 2042 | BUG_ON(!irqs_disabled()); |
1da177e4 LT |
2043 | if (rq1 == rq2) { |
2044 | spin_lock(&rq1->lock); | |
2045 | __acquire(rq2->lock); /* Fake it out ;) */ | |
2046 | } else { | |
c96d145e | 2047 | if (rq1 < rq2) { |
1da177e4 LT |
2048 | spin_lock(&rq1->lock); |
2049 | spin_lock(&rq2->lock); | |
2050 | } else { | |
2051 | spin_lock(&rq2->lock); | |
2052 | spin_lock(&rq1->lock); | |
2053 | } | |
2054 | } | |
6e82a3be IM |
2055 | update_rq_clock(rq1); |
2056 | update_rq_clock(rq2); | |
1da177e4 LT |
2057 | } |
2058 | ||
2059 | /* | |
2060 | * double_rq_unlock - safely unlock two runqueues | |
2061 | * | |
2062 | * Note this does not restore interrupts like task_rq_unlock, | |
2063 | * you need to do so manually after calling. | |
2064 | */ | |
70b97a7f | 2065 | static void double_rq_unlock(struct rq *rq1, struct rq *rq2) |
1da177e4 LT |
2066 | __releases(rq1->lock) |
2067 | __releases(rq2->lock) | |
2068 | { | |
2069 | spin_unlock(&rq1->lock); | |
2070 | if (rq1 != rq2) | |
2071 | spin_unlock(&rq2->lock); | |
2072 | else | |
2073 | __release(rq2->lock); | |
2074 | } | |
2075 | ||
2076 | /* | |
2077 | * double_lock_balance - lock the busiest runqueue, this_rq is locked already. | |
2078 | */ | |
e8fa1362 | 2079 | static int double_lock_balance(struct rq *this_rq, struct rq *busiest) |
1da177e4 LT |
2080 | __releases(this_rq->lock) |
2081 | __acquires(busiest->lock) | |
2082 | __acquires(this_rq->lock) | |
2083 | { | |
e8fa1362 SR |
2084 | int ret = 0; |
2085 | ||
054b9108 KK |
2086 | if (unlikely(!irqs_disabled())) { |
2087 | /* printk() doesn't work good under rq->lock */ | |
2088 | spin_unlock(&this_rq->lock); | |
2089 | BUG_ON(1); | |
2090 | } | |
1da177e4 | 2091 | if (unlikely(!spin_trylock(&busiest->lock))) { |
c96d145e | 2092 | if (busiest < this_rq) { |
1da177e4 LT |
2093 | spin_unlock(&this_rq->lock); |
2094 | spin_lock(&busiest->lock); | |
2095 | spin_lock(&this_rq->lock); | |
e8fa1362 | 2096 | ret = 1; |
1da177e4 LT |
2097 | } else |
2098 | spin_lock(&busiest->lock); | |
2099 | } | |
e8fa1362 | 2100 | return ret; |
1da177e4 LT |
2101 | } |
2102 | ||
1da177e4 LT |
2103 | /* |
2104 | * If dest_cpu is allowed for this process, migrate the task to it. | |
2105 | * This is accomplished by forcing the cpu_allowed mask to only | |
41a2d6cf | 2106 | * allow dest_cpu, which will force the cpu onto dest_cpu. Then |
1da177e4 LT |
2107 | * the cpu_allowed mask is restored. |
2108 | */ | |
36c8b586 | 2109 | static void sched_migrate_task(struct task_struct *p, int dest_cpu) |
1da177e4 | 2110 | { |
70b97a7f | 2111 | struct migration_req req; |
1da177e4 | 2112 | unsigned long flags; |
70b97a7f | 2113 | struct rq *rq; |
1da177e4 LT |
2114 | |
2115 | rq = task_rq_lock(p, &flags); | |
2116 | if (!cpu_isset(dest_cpu, p->cpus_allowed) | |
2117 | || unlikely(cpu_is_offline(dest_cpu))) | |
2118 | goto out; | |
2119 | ||
2120 | /* force the process onto the specified CPU */ | |
2121 | if (migrate_task(p, dest_cpu, &req)) { | |
2122 | /* Need to wait for migration thread (might exit: take ref). */ | |
2123 | struct task_struct *mt = rq->migration_thread; | |
36c8b586 | 2124 | |
1da177e4 LT |
2125 | get_task_struct(mt); |
2126 | task_rq_unlock(rq, &flags); | |
2127 | wake_up_process(mt); | |
2128 | put_task_struct(mt); | |
2129 | wait_for_completion(&req.done); | |
36c8b586 | 2130 | |
1da177e4 LT |
2131 | return; |
2132 | } | |
2133 | out: | |
2134 | task_rq_unlock(rq, &flags); | |
2135 | } | |
2136 | ||
2137 | /* | |
476d139c NP |
2138 | * sched_exec - execve() is a valuable balancing opportunity, because at |
2139 | * this point the task has the smallest effective memory and cache footprint. | |
1da177e4 LT |
2140 | */ |
2141 | void sched_exec(void) | |
2142 | { | |
1da177e4 | 2143 | int new_cpu, this_cpu = get_cpu(); |
476d139c | 2144 | new_cpu = sched_balance_self(this_cpu, SD_BALANCE_EXEC); |
1da177e4 | 2145 | put_cpu(); |
476d139c NP |
2146 | if (new_cpu != this_cpu) |
2147 | sched_migrate_task(current, new_cpu); | |
1da177e4 LT |
2148 | } |
2149 | ||
2150 | /* | |
2151 | * pull_task - move a task from a remote runqueue to the local runqueue. | |
2152 | * Both runqueues must be locked. | |
2153 | */ | |
dd41f596 IM |
2154 | static void pull_task(struct rq *src_rq, struct task_struct *p, |
2155 | struct rq *this_rq, int this_cpu) | |
1da177e4 | 2156 | { |
2e1cb74a | 2157 | deactivate_task(src_rq, p, 0); |
1da177e4 | 2158 | set_task_cpu(p, this_cpu); |
dd41f596 | 2159 | activate_task(this_rq, p, 0); |
1da177e4 LT |
2160 | /* |
2161 | * Note that idle threads have a prio of MAX_PRIO, for this test | |
2162 | * to be always true for them. | |
2163 | */ | |
dd41f596 | 2164 | check_preempt_curr(this_rq, p); |
1da177e4 LT |
2165 | } |
2166 | ||
2167 | /* | |
2168 | * can_migrate_task - may task p from runqueue rq be migrated to this_cpu? | |
2169 | */ | |
858119e1 | 2170 | static |
70b97a7f | 2171 | int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu, |
d15bcfdb | 2172 | struct sched_domain *sd, enum cpu_idle_type idle, |
95cdf3b7 | 2173 | int *all_pinned) |
1da177e4 LT |
2174 | { |
2175 | /* | |
2176 | * We do not migrate tasks that are: | |
2177 | * 1) running (obviously), or | |
2178 | * 2) cannot be migrated to this CPU due to cpus_allowed, or | |
2179 | * 3) are cache-hot on their current CPU. | |
2180 | */ | |
cc367732 IM |
2181 | if (!cpu_isset(this_cpu, p->cpus_allowed)) { |
2182 | schedstat_inc(p, se.nr_failed_migrations_affine); | |
1da177e4 | 2183 | return 0; |
cc367732 | 2184 | } |
81026794 NP |
2185 | *all_pinned = 0; |
2186 | ||
cc367732 IM |
2187 | if (task_running(rq, p)) { |
2188 | schedstat_inc(p, se.nr_failed_migrations_running); | |
81026794 | 2189 | return 0; |
cc367732 | 2190 | } |
1da177e4 | 2191 | |
da84d961 IM |
2192 | /* |
2193 | * Aggressive migration if: | |
2194 | * 1) task is cache cold, or | |
2195 | * 2) too many balance attempts have failed. | |
2196 | */ | |
2197 | ||
6bc1665b IM |
2198 | if (!task_hot(p, rq->clock, sd) || |
2199 | sd->nr_balance_failed > sd->cache_nice_tries) { | |
da84d961 | 2200 | #ifdef CONFIG_SCHEDSTATS |
cc367732 | 2201 | if (task_hot(p, rq->clock, sd)) { |
da84d961 | 2202 | schedstat_inc(sd, lb_hot_gained[idle]); |
cc367732 IM |
2203 | schedstat_inc(p, se.nr_forced_migrations); |
2204 | } | |
da84d961 IM |
2205 | #endif |
2206 | return 1; | |
2207 | } | |
2208 | ||
cc367732 IM |
2209 | if (task_hot(p, rq->clock, sd)) { |
2210 | schedstat_inc(p, se.nr_failed_migrations_hot); | |
da84d961 | 2211 | return 0; |
cc367732 | 2212 | } |
1da177e4 LT |
2213 | return 1; |
2214 | } | |
2215 | ||
e1d1484f PW |
2216 | static unsigned long |
2217 | balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
2218 | unsigned long max_load_move, struct sched_domain *sd, | |
2219 | enum cpu_idle_type idle, int *all_pinned, | |
2220 | int *this_best_prio, struct rq_iterator *iterator) | |
1da177e4 | 2221 | { |
b82d9fdd | 2222 | int loops = 0, pulled = 0, pinned = 0, skip_for_load; |
dd41f596 IM |
2223 | struct task_struct *p; |
2224 | long rem_load_move = max_load_move; | |
1da177e4 | 2225 | |
e1d1484f | 2226 | if (max_load_move == 0) |
1da177e4 LT |
2227 | goto out; |
2228 | ||
81026794 NP |
2229 | pinned = 1; |
2230 | ||
1da177e4 | 2231 | /* |
dd41f596 | 2232 | * Start the load-balancing iterator: |
1da177e4 | 2233 | */ |
dd41f596 IM |
2234 | p = iterator->start(iterator->arg); |
2235 | next: | |
b82d9fdd | 2236 | if (!p || loops++ > sysctl_sched_nr_migrate) |
1da177e4 | 2237 | goto out; |
50ddd969 | 2238 | /* |
b82d9fdd | 2239 | * To help distribute high priority tasks across CPUs we don't |
50ddd969 PW |
2240 | * skip a task if it will be the highest priority task (i.e. smallest |
2241 | * prio value) on its new queue regardless of its load weight | |
2242 | */ | |
dd41f596 IM |
2243 | skip_for_load = (p->se.load.weight >> 1) > rem_load_move + |
2244 | SCHED_LOAD_SCALE_FUZZ; | |
a4ac01c3 | 2245 | if ((skip_for_load && p->prio >= *this_best_prio) || |
dd41f596 | 2246 | !can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) { |
dd41f596 IM |
2247 | p = iterator->next(iterator->arg); |
2248 | goto next; | |
1da177e4 LT |
2249 | } |
2250 | ||
dd41f596 | 2251 | pull_task(busiest, p, this_rq, this_cpu); |
1da177e4 | 2252 | pulled++; |
dd41f596 | 2253 | rem_load_move -= p->se.load.weight; |
1da177e4 | 2254 | |
2dd73a4f | 2255 | /* |
b82d9fdd | 2256 | * We only want to steal up to the prescribed amount of weighted load. |
2dd73a4f | 2257 | */ |
e1d1484f | 2258 | if (rem_load_move > 0) { |
a4ac01c3 PW |
2259 | if (p->prio < *this_best_prio) |
2260 | *this_best_prio = p->prio; | |
dd41f596 IM |
2261 | p = iterator->next(iterator->arg); |
2262 | goto next; | |
1da177e4 LT |
2263 | } |
2264 | out: | |
2265 | /* | |
e1d1484f | 2266 | * Right now, this is one of only two places pull_task() is called, |
1da177e4 LT |
2267 | * so we can safely collect pull_task() stats here rather than |
2268 | * inside pull_task(). | |
2269 | */ | |
2270 | schedstat_add(sd, lb_gained[idle], pulled); | |
81026794 NP |
2271 | |
2272 | if (all_pinned) | |
2273 | *all_pinned = pinned; | |
e1d1484f PW |
2274 | |
2275 | return max_load_move - rem_load_move; | |
1da177e4 LT |
2276 | } |
2277 | ||
dd41f596 | 2278 | /* |
43010659 PW |
2279 | * move_tasks tries to move up to max_load_move weighted load from busiest to |
2280 | * this_rq, as part of a balancing operation within domain "sd". | |
2281 | * Returns 1 if successful and 0 otherwise. | |
dd41f596 IM |
2282 | * |
2283 | * Called with both runqueues locked. | |
2284 | */ | |
2285 | static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
43010659 | 2286 | unsigned long max_load_move, |
dd41f596 IM |
2287 | struct sched_domain *sd, enum cpu_idle_type idle, |
2288 | int *all_pinned) | |
2289 | { | |
5522d5d5 | 2290 | const struct sched_class *class = sched_class_highest; |
43010659 | 2291 | unsigned long total_load_moved = 0; |
a4ac01c3 | 2292 | int this_best_prio = this_rq->curr->prio; |
dd41f596 IM |
2293 | |
2294 | do { | |
43010659 PW |
2295 | total_load_moved += |
2296 | class->load_balance(this_rq, this_cpu, busiest, | |
e1d1484f | 2297 | max_load_move - total_load_moved, |
a4ac01c3 | 2298 | sd, idle, all_pinned, &this_best_prio); |
dd41f596 | 2299 | class = class->next; |
43010659 | 2300 | } while (class && max_load_move > total_load_moved); |
dd41f596 | 2301 | |
43010659 PW |
2302 | return total_load_moved > 0; |
2303 | } | |
2304 | ||
e1d1484f PW |
2305 | static int |
2306 | iter_move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
2307 | struct sched_domain *sd, enum cpu_idle_type idle, | |
2308 | struct rq_iterator *iterator) | |
2309 | { | |
2310 | struct task_struct *p = iterator->start(iterator->arg); | |
2311 | int pinned = 0; | |
2312 | ||
2313 | while (p) { | |
2314 | if (can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) { | |
2315 | pull_task(busiest, p, this_rq, this_cpu); | |
2316 | /* | |
2317 | * Right now, this is only the second place pull_task() | |
2318 | * is called, so we can safely collect pull_task() | |
2319 | * stats here rather than inside pull_task(). | |
2320 | */ | |
2321 | schedstat_inc(sd, lb_gained[idle]); | |
2322 | ||
2323 | return 1; | |
2324 | } | |
2325 | p = iterator->next(iterator->arg); | |
2326 | } | |
2327 | ||
2328 | return 0; | |
2329 | } | |
2330 | ||
43010659 PW |
2331 | /* |
2332 | * move_one_task tries to move exactly one task from busiest to this_rq, as | |
2333 | * part of active balancing operations within "domain". | |
2334 | * Returns 1 if successful and 0 otherwise. | |
2335 | * | |
2336 | * Called with both runqueues locked. | |
2337 | */ | |
2338 | static int move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
2339 | struct sched_domain *sd, enum cpu_idle_type idle) | |
2340 | { | |
5522d5d5 | 2341 | const struct sched_class *class; |
43010659 PW |
2342 | |
2343 | for (class = sched_class_highest; class; class = class->next) | |
e1d1484f | 2344 | if (class->move_one_task(this_rq, this_cpu, busiest, sd, idle)) |
43010659 PW |
2345 | return 1; |
2346 | ||
2347 | return 0; | |
dd41f596 IM |
2348 | } |
2349 | ||
1da177e4 LT |
2350 | /* |
2351 | * find_busiest_group finds and returns the busiest CPU group within the | |
48f24c4d IM |
2352 | * domain. It calculates and returns the amount of weighted load which |
2353 | * should be moved to restore balance via the imbalance parameter. | |
1da177e4 LT |
2354 | */ |
2355 | static struct sched_group * | |
2356 | find_busiest_group(struct sched_domain *sd, int this_cpu, | |
dd41f596 IM |
2357 | unsigned long *imbalance, enum cpu_idle_type idle, |
2358 | int *sd_idle, cpumask_t *cpus, int *balance) | |
1da177e4 LT |
2359 | { |
2360 | struct sched_group *busiest = NULL, *this = NULL, *group = sd->groups; | |
2361 | unsigned long max_load, avg_load, total_load, this_load, total_pwr; | |
0c117f1b | 2362 | unsigned long max_pull; |
2dd73a4f PW |
2363 | unsigned long busiest_load_per_task, busiest_nr_running; |
2364 | unsigned long this_load_per_task, this_nr_running; | |
908a7c1b | 2365 | int load_idx, group_imb = 0; |
5c45bf27 SS |
2366 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) |
2367 | int power_savings_balance = 1; | |
2368 | unsigned long leader_nr_running = 0, min_load_per_task = 0; | |
2369 | unsigned long min_nr_running = ULONG_MAX; | |
2370 | struct sched_group *group_min = NULL, *group_leader = NULL; | |
2371 | #endif | |
1da177e4 LT |
2372 | |
2373 | max_load = this_load = total_load = total_pwr = 0; | |
2dd73a4f PW |
2374 | busiest_load_per_task = busiest_nr_running = 0; |
2375 | this_load_per_task = this_nr_running = 0; | |
d15bcfdb | 2376 | if (idle == CPU_NOT_IDLE) |
7897986b | 2377 | load_idx = sd->busy_idx; |
d15bcfdb | 2378 | else if (idle == CPU_NEWLY_IDLE) |
7897986b NP |
2379 | load_idx = sd->newidle_idx; |
2380 | else | |
2381 | load_idx = sd->idle_idx; | |
1da177e4 LT |
2382 | |
2383 | do { | |
908a7c1b | 2384 | unsigned long load, group_capacity, max_cpu_load, min_cpu_load; |
1da177e4 LT |
2385 | int local_group; |
2386 | int i; | |
908a7c1b | 2387 | int __group_imb = 0; |
783609c6 | 2388 | unsigned int balance_cpu = -1, first_idle_cpu = 0; |
2dd73a4f | 2389 | unsigned long sum_nr_running, sum_weighted_load; |
1da177e4 LT |
2390 | |
2391 | local_group = cpu_isset(this_cpu, group->cpumask); | |
2392 | ||
783609c6 SS |
2393 | if (local_group) |
2394 | balance_cpu = first_cpu(group->cpumask); | |
2395 | ||
1da177e4 | 2396 | /* Tally up the load of all CPUs in the group */ |
2dd73a4f | 2397 | sum_weighted_load = sum_nr_running = avg_load = 0; |
908a7c1b KC |
2398 | max_cpu_load = 0; |
2399 | min_cpu_load = ~0UL; | |
1da177e4 LT |
2400 | |
2401 | for_each_cpu_mask(i, group->cpumask) { | |
0a2966b4 CL |
2402 | struct rq *rq; |
2403 | ||
2404 | if (!cpu_isset(i, *cpus)) | |
2405 | continue; | |
2406 | ||
2407 | rq = cpu_rq(i); | |
2dd73a4f | 2408 | |
9439aab8 | 2409 | if (*sd_idle && rq->nr_running) |
5969fe06 NP |
2410 | *sd_idle = 0; |
2411 | ||
1da177e4 | 2412 | /* Bias balancing toward cpus of our domain */ |
783609c6 SS |
2413 | if (local_group) { |
2414 | if (idle_cpu(i) && !first_idle_cpu) { | |
2415 | first_idle_cpu = 1; | |
2416 | balance_cpu = i; | |
2417 | } | |
2418 | ||
a2000572 | 2419 | load = target_load(i, load_idx); |
908a7c1b | 2420 | } else { |
a2000572 | 2421 | load = source_load(i, load_idx); |
908a7c1b KC |
2422 | if (load > max_cpu_load) |
2423 | max_cpu_load = load; | |
2424 | if (min_cpu_load > load) | |
2425 | min_cpu_load = load; | |
2426 | } | |
1da177e4 LT |
2427 | |
2428 | avg_load += load; | |
2dd73a4f | 2429 | sum_nr_running += rq->nr_running; |
dd41f596 | 2430 | sum_weighted_load += weighted_cpuload(i); |
1da177e4 LT |
2431 | } |
2432 | ||
783609c6 SS |
2433 | /* |
2434 | * First idle cpu or the first cpu(busiest) in this sched group | |
2435 | * is eligible for doing load balancing at this and above | |
9439aab8 SS |
2436 | * domains. In the newly idle case, we will allow all the cpu's |
2437 | * to do the newly idle load balance. | |
783609c6 | 2438 | */ |
9439aab8 SS |
2439 | if (idle != CPU_NEWLY_IDLE && local_group && |
2440 | balance_cpu != this_cpu && balance) { | |
783609c6 SS |
2441 | *balance = 0; |
2442 | goto ret; | |
2443 | } | |
2444 | ||
1da177e4 | 2445 | total_load += avg_load; |
5517d86b | 2446 | total_pwr += group->__cpu_power; |
1da177e4 LT |
2447 | |
2448 | /* Adjust by relative CPU power of the group */ | |
5517d86b ED |
2449 | avg_load = sg_div_cpu_power(group, |
2450 | avg_load * SCHED_LOAD_SCALE); | |
1da177e4 | 2451 | |
908a7c1b KC |
2452 | if ((max_cpu_load - min_cpu_load) > SCHED_LOAD_SCALE) |
2453 | __group_imb = 1; | |
2454 | ||
5517d86b | 2455 | group_capacity = group->__cpu_power / SCHED_LOAD_SCALE; |
5c45bf27 | 2456 | |
1da177e4 LT |
2457 | if (local_group) { |
2458 | this_load = avg_load; | |
2459 | this = group; | |
2dd73a4f PW |
2460 | this_nr_running = sum_nr_running; |
2461 | this_load_per_task = sum_weighted_load; | |
2462 | } else if (avg_load > max_load && | |
908a7c1b | 2463 | (sum_nr_running > group_capacity || __group_imb)) { |
1da177e4 LT |
2464 | max_load = avg_load; |
2465 | busiest = group; | |
2dd73a4f PW |
2466 | busiest_nr_running = sum_nr_running; |
2467 | busiest_load_per_task = sum_weighted_load; | |
908a7c1b | 2468 | group_imb = __group_imb; |
1da177e4 | 2469 | } |
5c45bf27 SS |
2470 | |
2471 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) | |
2472 | /* | |
2473 | * Busy processors will not participate in power savings | |
2474 | * balance. | |
2475 | */ | |
dd41f596 IM |
2476 | if (idle == CPU_NOT_IDLE || |
2477 | !(sd->flags & SD_POWERSAVINGS_BALANCE)) | |
2478 | goto group_next; | |
5c45bf27 SS |
2479 | |
2480 | /* | |
2481 | * If the local group is idle or completely loaded | |
2482 | * no need to do power savings balance at this domain | |
2483 | */ | |
2484 | if (local_group && (this_nr_running >= group_capacity || | |
2485 | !this_nr_running)) | |
2486 | power_savings_balance = 0; | |
2487 | ||
dd41f596 | 2488 | /* |
5c45bf27 SS |
2489 | * If a group is already running at full capacity or idle, |
2490 | * don't include that group in power savings calculations | |
dd41f596 IM |
2491 | */ |
2492 | if (!power_savings_balance || sum_nr_running >= group_capacity | |
5c45bf27 | 2493 | || !sum_nr_running) |
dd41f596 | 2494 | goto group_next; |
5c45bf27 | 2495 | |
dd41f596 | 2496 | /* |
5c45bf27 | 2497 | * Calculate the group which has the least non-idle load. |
dd41f596 IM |
2498 | * This is the group from where we need to pick up the load |
2499 | * for saving power | |
2500 | */ | |
2501 | if ((sum_nr_running < min_nr_running) || | |
2502 | (sum_nr_running == min_nr_running && | |
5c45bf27 SS |
2503 | first_cpu(group->cpumask) < |
2504 | first_cpu(group_min->cpumask))) { | |
dd41f596 IM |
2505 | group_min = group; |
2506 | min_nr_running = sum_nr_running; | |
5c45bf27 SS |
2507 | min_load_per_task = sum_weighted_load / |
2508 | sum_nr_running; | |
dd41f596 | 2509 | } |
5c45bf27 | 2510 | |
dd41f596 | 2511 | /* |
5c45bf27 | 2512 | * Calculate the group which is almost near its |
dd41f596 IM |
2513 | * capacity but still has some space to pick up some load |
2514 | * from other group and save more power | |
2515 | */ | |
2516 | if (sum_nr_running <= group_capacity - 1) { | |
2517 | if (sum_nr_running > leader_nr_running || | |
2518 | (sum_nr_running == leader_nr_running && | |
2519 | first_cpu(group->cpumask) > | |
2520 | first_cpu(group_leader->cpumask))) { | |
2521 | group_leader = group; | |
2522 | leader_nr_running = sum_nr_running; | |
2523 | } | |
48f24c4d | 2524 | } |
5c45bf27 SS |
2525 | group_next: |
2526 | #endif | |
1da177e4 LT |
2527 | group = group->next; |
2528 | } while (group != sd->groups); | |
2529 | ||
2dd73a4f | 2530 | if (!busiest || this_load >= max_load || busiest_nr_running == 0) |
1da177e4 LT |
2531 | goto out_balanced; |
2532 | ||
2533 | avg_load = (SCHED_LOAD_SCALE * total_load) / total_pwr; | |
2534 | ||
2535 | if (this_load >= avg_load || | |
2536 | 100*max_load <= sd->imbalance_pct*this_load) | |
2537 | goto out_balanced; | |
2538 | ||
2dd73a4f | 2539 | busiest_load_per_task /= busiest_nr_running; |
908a7c1b KC |
2540 | if (group_imb) |
2541 | busiest_load_per_task = min(busiest_load_per_task, avg_load); | |
2542 | ||
1da177e4 LT |
2543 | /* |
2544 | * We're trying to get all the cpus to the average_load, so we don't | |
2545 | * want to push ourselves above the average load, nor do we wish to | |
2546 | * reduce the max loaded cpu below the average load, as either of these | |
2547 | * actions would just result in more rebalancing later, and ping-pong | |
2548 | * tasks around. Thus we look for the minimum possible imbalance. | |
2549 | * Negative imbalances (*we* are more loaded than anyone else) will | |
2550 | * be counted as no imbalance for these purposes -- we can't fix that | |
41a2d6cf | 2551 | * by pulling tasks to us. Be careful of negative numbers as they'll |
1da177e4 LT |
2552 | * appear as very large values with unsigned longs. |
2553 | */ | |
2dd73a4f PW |
2554 | if (max_load <= busiest_load_per_task) |
2555 | goto out_balanced; | |
2556 | ||
2557 | /* | |
2558 | * In the presence of smp nice balancing, certain scenarios can have | |
2559 | * max load less than avg load(as we skip the groups at or below | |
2560 | * its cpu_power, while calculating max_load..) | |
2561 | */ | |
2562 | if (max_load < avg_load) { | |
2563 | *imbalance = 0; | |
2564 | goto small_imbalance; | |
2565 | } | |
0c117f1b SS |
2566 | |
2567 | /* Don't want to pull so many tasks that a group would go idle */ | |
2dd73a4f | 2568 | max_pull = min(max_load - avg_load, max_load - busiest_load_per_task); |
0c117f1b | 2569 | |
1da177e4 | 2570 | /* How much load to actually move to equalise the imbalance */ |
5517d86b ED |
2571 | *imbalance = min(max_pull * busiest->__cpu_power, |
2572 | (avg_load - this_load) * this->__cpu_power) | |
1da177e4 LT |
2573 | / SCHED_LOAD_SCALE; |
2574 | ||
2dd73a4f PW |
2575 | /* |
2576 | * if *imbalance is less than the average load per runnable task | |
2577 | * there is no gaurantee that any tasks will be moved so we'll have | |
2578 | * a think about bumping its value to force at least one task to be | |
2579 | * moved | |
2580 | */ | |
7fd0d2dd | 2581 | if (*imbalance < busiest_load_per_task) { |
48f24c4d | 2582 | unsigned long tmp, pwr_now, pwr_move; |
2dd73a4f PW |
2583 | unsigned int imbn; |
2584 | ||
2585 | small_imbalance: | |
2586 | pwr_move = pwr_now = 0; | |
2587 | imbn = 2; | |
2588 | if (this_nr_running) { | |
2589 | this_load_per_task /= this_nr_running; | |
2590 | if (busiest_load_per_task > this_load_per_task) | |
2591 | imbn = 1; | |
2592 | } else | |
2593 | this_load_per_task = SCHED_LOAD_SCALE; | |
1da177e4 | 2594 | |
dd41f596 IM |
2595 | if (max_load - this_load + SCHED_LOAD_SCALE_FUZZ >= |
2596 | busiest_load_per_task * imbn) { | |
2dd73a4f | 2597 | *imbalance = busiest_load_per_task; |
1da177e4 LT |
2598 | return busiest; |
2599 | } | |
2600 | ||
2601 | /* | |
2602 | * OK, we don't have enough imbalance to justify moving tasks, | |
2603 | * however we may be able to increase total CPU power used by | |
2604 | * moving them. | |
2605 | */ | |
2606 | ||
5517d86b ED |
2607 | pwr_now += busiest->__cpu_power * |
2608 | min(busiest_load_per_task, max_load); | |
2609 | pwr_now += this->__cpu_power * | |
2610 | min(this_load_per_task, this_load); | |
1da177e4 LT |
2611 | pwr_now /= SCHED_LOAD_SCALE; |
2612 | ||
2613 | /* Amount of load we'd subtract */ | |
5517d86b ED |
2614 | tmp = sg_div_cpu_power(busiest, |
2615 | busiest_load_per_task * SCHED_LOAD_SCALE); | |
1da177e4 | 2616 | if (max_load > tmp) |
5517d86b | 2617 | pwr_move += busiest->__cpu_power * |
2dd73a4f | 2618 | min(busiest_load_per_task, max_load - tmp); |
1da177e4 LT |
2619 | |
2620 | /* Amount of load we'd add */ | |
5517d86b | 2621 | if (max_load * busiest->__cpu_power < |
33859f7f | 2622 | busiest_load_per_task * SCHED_LOAD_SCALE) |
5517d86b ED |
2623 | tmp = sg_div_cpu_power(this, |
2624 | max_load * busiest->__cpu_power); | |
1da177e4 | 2625 | else |
5517d86b ED |
2626 | tmp = sg_div_cpu_power(this, |
2627 | busiest_load_per_task * SCHED_LOAD_SCALE); | |
2628 | pwr_move += this->__cpu_power * | |
2629 | min(this_load_per_task, this_load + tmp); | |
1da177e4 LT |
2630 | pwr_move /= SCHED_LOAD_SCALE; |
2631 | ||
2632 | /* Move if we gain throughput */ | |
7fd0d2dd SS |
2633 | if (pwr_move > pwr_now) |
2634 | *imbalance = busiest_load_per_task; | |
1da177e4 LT |
2635 | } |
2636 | ||
1da177e4 LT |
2637 | return busiest; |
2638 | ||
2639 | out_balanced: | |
5c45bf27 | 2640 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) |
d15bcfdb | 2641 | if (idle == CPU_NOT_IDLE || !(sd->flags & SD_POWERSAVINGS_BALANCE)) |
5c45bf27 | 2642 | goto ret; |
1da177e4 | 2643 | |
5c45bf27 SS |
2644 | if (this == group_leader && group_leader != group_min) { |
2645 | *imbalance = min_load_per_task; | |
2646 | return group_min; | |
2647 | } | |
5c45bf27 | 2648 | #endif |
783609c6 | 2649 | ret: |
1da177e4 LT |
2650 | *imbalance = 0; |
2651 | return NULL; | |
2652 | } | |
2653 | ||
2654 | /* | |
2655 | * find_busiest_queue - find the busiest runqueue among the cpus in group. | |
2656 | */ | |
70b97a7f | 2657 | static struct rq * |
d15bcfdb | 2658 | find_busiest_queue(struct sched_group *group, enum cpu_idle_type idle, |
0a2966b4 | 2659 | unsigned long imbalance, cpumask_t *cpus) |
1da177e4 | 2660 | { |
70b97a7f | 2661 | struct rq *busiest = NULL, *rq; |
2dd73a4f | 2662 | unsigned long max_load = 0; |
1da177e4 LT |
2663 | int i; |
2664 | ||
2665 | for_each_cpu_mask(i, group->cpumask) { | |
dd41f596 | 2666 | unsigned long wl; |
0a2966b4 CL |
2667 | |
2668 | if (!cpu_isset(i, *cpus)) | |
2669 | continue; | |
2670 | ||
48f24c4d | 2671 | rq = cpu_rq(i); |
dd41f596 | 2672 | wl = weighted_cpuload(i); |
2dd73a4f | 2673 | |
dd41f596 | 2674 | if (rq->nr_running == 1 && wl > imbalance) |
2dd73a4f | 2675 | continue; |
1da177e4 | 2676 | |
dd41f596 IM |
2677 | if (wl > max_load) { |
2678 | max_load = wl; | |
48f24c4d | 2679 | busiest = rq; |
1da177e4 LT |
2680 | } |
2681 | } | |
2682 | ||
2683 | return busiest; | |
2684 | } | |
2685 | ||
77391d71 NP |
2686 | /* |
2687 | * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but | |
2688 | * so long as it is large enough. | |
2689 | */ | |
2690 | #define MAX_PINNED_INTERVAL 512 | |
2691 | ||
1da177e4 LT |
2692 | /* |
2693 | * Check this_cpu to ensure it is balanced within domain. Attempt to move | |
2694 | * tasks if there is an imbalance. | |
1da177e4 | 2695 | */ |
70b97a7f | 2696 | static int load_balance(int this_cpu, struct rq *this_rq, |
d15bcfdb | 2697 | struct sched_domain *sd, enum cpu_idle_type idle, |
783609c6 | 2698 | int *balance) |
1da177e4 | 2699 | { |
43010659 | 2700 | int ld_moved, all_pinned = 0, active_balance = 0, sd_idle = 0; |
1da177e4 | 2701 | struct sched_group *group; |
1da177e4 | 2702 | unsigned long imbalance; |
70b97a7f | 2703 | struct rq *busiest; |
0a2966b4 | 2704 | cpumask_t cpus = CPU_MASK_ALL; |
fe2eea3f | 2705 | unsigned long flags; |
5969fe06 | 2706 | |
89c4710e SS |
2707 | /* |
2708 | * When power savings policy is enabled for the parent domain, idle | |
2709 | * sibling can pick up load irrespective of busy siblings. In this case, | |
dd41f596 | 2710 | * let the state of idle sibling percolate up as CPU_IDLE, instead of |
d15bcfdb | 2711 | * portraying it as CPU_NOT_IDLE. |
89c4710e | 2712 | */ |
d15bcfdb | 2713 | if (idle != CPU_NOT_IDLE && sd->flags & SD_SHARE_CPUPOWER && |
89c4710e | 2714 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
5969fe06 | 2715 | sd_idle = 1; |
1da177e4 | 2716 | |
2d72376b | 2717 | schedstat_inc(sd, lb_count[idle]); |
1da177e4 | 2718 | |
0a2966b4 CL |
2719 | redo: |
2720 | group = find_busiest_group(sd, this_cpu, &imbalance, idle, &sd_idle, | |
783609c6 SS |
2721 | &cpus, balance); |
2722 | ||
06066714 | 2723 | if (*balance == 0) |
783609c6 | 2724 | goto out_balanced; |
783609c6 | 2725 | |
1da177e4 LT |
2726 | if (!group) { |
2727 | schedstat_inc(sd, lb_nobusyg[idle]); | |
2728 | goto out_balanced; | |
2729 | } | |
2730 | ||
0a2966b4 | 2731 | busiest = find_busiest_queue(group, idle, imbalance, &cpus); |
1da177e4 LT |
2732 | if (!busiest) { |
2733 | schedstat_inc(sd, lb_nobusyq[idle]); | |
2734 | goto out_balanced; | |
2735 | } | |
2736 | ||
db935dbd | 2737 | BUG_ON(busiest == this_rq); |
1da177e4 LT |
2738 | |
2739 | schedstat_add(sd, lb_imbalance[idle], imbalance); | |
2740 | ||
43010659 | 2741 | ld_moved = 0; |
1da177e4 LT |
2742 | if (busiest->nr_running > 1) { |
2743 | /* | |
2744 | * Attempt to move tasks. If find_busiest_group has found | |
2745 | * an imbalance but busiest->nr_running <= 1, the group is | |
43010659 | 2746 | * still unbalanced. ld_moved simply stays zero, so it is |
1da177e4 LT |
2747 | * correctly treated as an imbalance. |
2748 | */ | |
fe2eea3f | 2749 | local_irq_save(flags); |
e17224bf | 2750 | double_rq_lock(this_rq, busiest); |
43010659 | 2751 | ld_moved = move_tasks(this_rq, this_cpu, busiest, |
48f24c4d | 2752 | imbalance, sd, idle, &all_pinned); |
e17224bf | 2753 | double_rq_unlock(this_rq, busiest); |
fe2eea3f | 2754 | local_irq_restore(flags); |
81026794 | 2755 | |
46cb4b7c SS |
2756 | /* |
2757 | * some other cpu did the load balance for us. | |
2758 | */ | |
43010659 | 2759 | if (ld_moved && this_cpu != smp_processor_id()) |
46cb4b7c SS |
2760 | resched_cpu(this_cpu); |
2761 | ||
81026794 | 2762 | /* All tasks on this runqueue were pinned by CPU affinity */ |
0a2966b4 CL |
2763 | if (unlikely(all_pinned)) { |
2764 | cpu_clear(cpu_of(busiest), cpus); | |
2765 | if (!cpus_empty(cpus)) | |
2766 | goto redo; | |
81026794 | 2767 | goto out_balanced; |
0a2966b4 | 2768 | } |
1da177e4 | 2769 | } |
81026794 | 2770 | |
43010659 | 2771 | if (!ld_moved) { |
1da177e4 LT |
2772 | schedstat_inc(sd, lb_failed[idle]); |
2773 | sd->nr_balance_failed++; | |
2774 | ||
2775 | if (unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2)) { | |
1da177e4 | 2776 | |
fe2eea3f | 2777 | spin_lock_irqsave(&busiest->lock, flags); |
fa3b6ddc SS |
2778 | |
2779 | /* don't kick the migration_thread, if the curr | |
2780 | * task on busiest cpu can't be moved to this_cpu | |
2781 | */ | |
2782 | if (!cpu_isset(this_cpu, busiest->curr->cpus_allowed)) { | |
fe2eea3f | 2783 | spin_unlock_irqrestore(&busiest->lock, flags); |
fa3b6ddc SS |
2784 | all_pinned = 1; |
2785 | goto out_one_pinned; | |
2786 | } | |
2787 | ||
1da177e4 LT |
2788 | if (!busiest->active_balance) { |
2789 | busiest->active_balance = 1; | |
2790 | busiest->push_cpu = this_cpu; | |
81026794 | 2791 | active_balance = 1; |
1da177e4 | 2792 | } |
fe2eea3f | 2793 | spin_unlock_irqrestore(&busiest->lock, flags); |
81026794 | 2794 | if (active_balance) |
1da177e4 LT |
2795 | wake_up_process(busiest->migration_thread); |
2796 | ||
2797 | /* | |
2798 | * We've kicked active balancing, reset the failure | |
2799 | * counter. | |
2800 | */ | |
39507451 | 2801 | sd->nr_balance_failed = sd->cache_nice_tries+1; |
1da177e4 | 2802 | } |
81026794 | 2803 | } else |
1da177e4 LT |
2804 | sd->nr_balance_failed = 0; |
2805 | ||
81026794 | 2806 | if (likely(!active_balance)) { |
1da177e4 LT |
2807 | /* We were unbalanced, so reset the balancing interval */ |
2808 | sd->balance_interval = sd->min_interval; | |
81026794 NP |
2809 | } else { |
2810 | /* | |
2811 | * If we've begun active balancing, start to back off. This | |
2812 | * case may not be covered by the all_pinned logic if there | |
2813 | * is only 1 task on the busy runqueue (because we don't call | |
2814 | * move_tasks). | |
2815 | */ | |
2816 | if (sd->balance_interval < sd->max_interval) | |
2817 | sd->balance_interval *= 2; | |
1da177e4 LT |
2818 | } |
2819 | ||
43010659 | 2820 | if (!ld_moved && !sd_idle && sd->flags & SD_SHARE_CPUPOWER && |
89c4710e | 2821 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
5969fe06 | 2822 | return -1; |
43010659 | 2823 | return ld_moved; |
1da177e4 LT |
2824 | |
2825 | out_balanced: | |
1da177e4 LT |
2826 | schedstat_inc(sd, lb_balanced[idle]); |
2827 | ||
16cfb1c0 | 2828 | sd->nr_balance_failed = 0; |
fa3b6ddc SS |
2829 | |
2830 | out_one_pinned: | |
1da177e4 | 2831 | /* tune up the balancing interval */ |
77391d71 NP |
2832 | if ((all_pinned && sd->balance_interval < MAX_PINNED_INTERVAL) || |
2833 | (sd->balance_interval < sd->max_interval)) | |
1da177e4 LT |
2834 | sd->balance_interval *= 2; |
2835 | ||
48f24c4d | 2836 | if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && |
89c4710e | 2837 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
5969fe06 | 2838 | return -1; |
1da177e4 LT |
2839 | return 0; |
2840 | } | |
2841 | ||
2842 | /* | |
2843 | * Check this_cpu to ensure it is balanced within domain. Attempt to move | |
2844 | * tasks if there is an imbalance. | |
2845 | * | |
d15bcfdb | 2846 | * Called from schedule when this_rq is about to become idle (CPU_NEWLY_IDLE). |
1da177e4 LT |
2847 | * this_rq is locked. |
2848 | */ | |
48f24c4d | 2849 | static int |
70b97a7f | 2850 | load_balance_newidle(int this_cpu, struct rq *this_rq, struct sched_domain *sd) |
1da177e4 LT |
2851 | { |
2852 | struct sched_group *group; | |
70b97a7f | 2853 | struct rq *busiest = NULL; |
1da177e4 | 2854 | unsigned long imbalance; |
43010659 | 2855 | int ld_moved = 0; |
5969fe06 | 2856 | int sd_idle = 0; |
969bb4e4 | 2857 | int all_pinned = 0; |
0a2966b4 | 2858 | cpumask_t cpus = CPU_MASK_ALL; |
5969fe06 | 2859 | |
89c4710e SS |
2860 | /* |
2861 | * When power savings policy is enabled for the parent domain, idle | |
2862 | * sibling can pick up load irrespective of busy siblings. In this case, | |
2863 | * let the state of idle sibling percolate up as IDLE, instead of | |
d15bcfdb | 2864 | * portraying it as CPU_NOT_IDLE. |
89c4710e SS |
2865 | */ |
2866 | if (sd->flags & SD_SHARE_CPUPOWER && | |
2867 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) | |
5969fe06 | 2868 | sd_idle = 1; |
1da177e4 | 2869 | |
2d72376b | 2870 | schedstat_inc(sd, lb_count[CPU_NEWLY_IDLE]); |
0a2966b4 | 2871 | redo: |
d15bcfdb | 2872 | group = find_busiest_group(sd, this_cpu, &imbalance, CPU_NEWLY_IDLE, |
783609c6 | 2873 | &sd_idle, &cpus, NULL); |
1da177e4 | 2874 | if (!group) { |
d15bcfdb | 2875 | schedstat_inc(sd, lb_nobusyg[CPU_NEWLY_IDLE]); |
16cfb1c0 | 2876 | goto out_balanced; |
1da177e4 LT |
2877 | } |
2878 | ||
d15bcfdb | 2879 | busiest = find_busiest_queue(group, CPU_NEWLY_IDLE, imbalance, |
0a2966b4 | 2880 | &cpus); |
db935dbd | 2881 | if (!busiest) { |
d15bcfdb | 2882 | schedstat_inc(sd, lb_nobusyq[CPU_NEWLY_IDLE]); |
16cfb1c0 | 2883 | goto out_balanced; |
1da177e4 LT |
2884 | } |
2885 | ||
db935dbd NP |
2886 | BUG_ON(busiest == this_rq); |
2887 | ||
d15bcfdb | 2888 | schedstat_add(sd, lb_imbalance[CPU_NEWLY_IDLE], imbalance); |
d6d5cfaf | 2889 | |
43010659 | 2890 | ld_moved = 0; |
d6d5cfaf NP |
2891 | if (busiest->nr_running > 1) { |
2892 | /* Attempt to move tasks */ | |
2893 | double_lock_balance(this_rq, busiest); | |
6e82a3be IM |
2894 | /* this_rq->clock is already updated */ |
2895 | update_rq_clock(busiest); | |
43010659 | 2896 | ld_moved = move_tasks(this_rq, this_cpu, busiest, |
969bb4e4 SS |
2897 | imbalance, sd, CPU_NEWLY_IDLE, |
2898 | &all_pinned); | |
d6d5cfaf | 2899 | spin_unlock(&busiest->lock); |
0a2966b4 | 2900 | |
969bb4e4 | 2901 | if (unlikely(all_pinned)) { |
0a2966b4 CL |
2902 | cpu_clear(cpu_of(busiest), cpus); |
2903 | if (!cpus_empty(cpus)) | |
2904 | goto redo; | |
2905 | } | |
d6d5cfaf NP |
2906 | } |
2907 | ||
43010659 | 2908 | if (!ld_moved) { |
d15bcfdb | 2909 | schedstat_inc(sd, lb_failed[CPU_NEWLY_IDLE]); |
89c4710e SS |
2910 | if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && |
2911 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) | |
5969fe06 NP |
2912 | return -1; |
2913 | } else | |
16cfb1c0 | 2914 | sd->nr_balance_failed = 0; |
1da177e4 | 2915 | |
43010659 | 2916 | return ld_moved; |
16cfb1c0 NP |
2917 | |
2918 | out_balanced: | |
d15bcfdb | 2919 | schedstat_inc(sd, lb_balanced[CPU_NEWLY_IDLE]); |
48f24c4d | 2920 | if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && |
89c4710e | 2921 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
5969fe06 | 2922 | return -1; |
16cfb1c0 | 2923 | sd->nr_balance_failed = 0; |
48f24c4d | 2924 | |
16cfb1c0 | 2925 | return 0; |
1da177e4 LT |
2926 | } |
2927 | ||
2928 | /* | |
2929 | * idle_balance is called by schedule() if this_cpu is about to become | |
2930 | * idle. Attempts to pull tasks from other CPUs. | |
2931 | */ | |
70b97a7f | 2932 | static void idle_balance(int this_cpu, struct rq *this_rq) |
1da177e4 LT |
2933 | { |
2934 | struct sched_domain *sd; | |
dd41f596 IM |
2935 | int pulled_task = -1; |
2936 | unsigned long next_balance = jiffies + HZ; | |
1da177e4 LT |
2937 | |
2938 | for_each_domain(this_cpu, sd) { | |
92c4ca5c CL |
2939 | unsigned long interval; |
2940 | ||
2941 | if (!(sd->flags & SD_LOAD_BALANCE)) | |
2942 | continue; | |
2943 | ||
2944 | if (sd->flags & SD_BALANCE_NEWIDLE) | |
48f24c4d | 2945 | /* If we've pulled tasks over stop searching: */ |
1bd77f2d | 2946 | pulled_task = load_balance_newidle(this_cpu, |
92c4ca5c CL |
2947 | this_rq, sd); |
2948 | ||
2949 | interval = msecs_to_jiffies(sd->balance_interval); | |
2950 | if (time_after(next_balance, sd->last_balance + interval)) | |
2951 | next_balance = sd->last_balance + interval; | |
2952 | if (pulled_task) | |
2953 | break; | |
1da177e4 | 2954 | } |
dd41f596 | 2955 | if (pulled_task || time_after(jiffies, this_rq->next_balance)) { |
1bd77f2d CL |
2956 | /* |
2957 | * We are going idle. next_balance may be set based on | |
2958 | * a busy processor. So reset next_balance. | |
2959 | */ | |
2960 | this_rq->next_balance = next_balance; | |
dd41f596 | 2961 | } |
1da177e4 LT |
2962 | } |
2963 | ||
2964 | /* | |
2965 | * active_load_balance is run by migration threads. It pushes running tasks | |
2966 | * off the busiest CPU onto idle CPUs. It requires at least 1 task to be | |
2967 | * running on each physical CPU where possible, and avoids physical / | |
2968 | * logical imbalances. | |
2969 | * | |
2970 | * Called with busiest_rq locked. | |
2971 | */ | |
70b97a7f | 2972 | static void active_load_balance(struct rq *busiest_rq, int busiest_cpu) |
1da177e4 | 2973 | { |
39507451 | 2974 | int target_cpu = busiest_rq->push_cpu; |
70b97a7f IM |
2975 | struct sched_domain *sd; |
2976 | struct rq *target_rq; | |
39507451 | 2977 | |
48f24c4d | 2978 | /* Is there any task to move? */ |
39507451 | 2979 | if (busiest_rq->nr_running <= 1) |
39507451 NP |
2980 | return; |
2981 | ||
2982 | target_rq = cpu_rq(target_cpu); | |
1da177e4 LT |
2983 | |
2984 | /* | |
39507451 | 2985 | * This condition is "impossible", if it occurs |
41a2d6cf | 2986 | * we need to fix it. Originally reported by |
39507451 | 2987 | * Bjorn Helgaas on a 128-cpu setup. |
1da177e4 | 2988 | */ |
39507451 | 2989 | BUG_ON(busiest_rq == target_rq); |
1da177e4 | 2990 | |
39507451 NP |
2991 | /* move a task from busiest_rq to target_rq */ |
2992 | double_lock_balance(busiest_rq, target_rq); | |
6e82a3be IM |
2993 | update_rq_clock(busiest_rq); |
2994 | update_rq_clock(target_rq); | |
39507451 NP |
2995 | |
2996 | /* Search for an sd spanning us and the target CPU. */ | |
c96d145e | 2997 | for_each_domain(target_cpu, sd) { |
39507451 | 2998 | if ((sd->flags & SD_LOAD_BALANCE) && |
48f24c4d | 2999 | cpu_isset(busiest_cpu, sd->span)) |
39507451 | 3000 | break; |
c96d145e | 3001 | } |
39507451 | 3002 | |
48f24c4d | 3003 | if (likely(sd)) { |
2d72376b | 3004 | schedstat_inc(sd, alb_count); |
39507451 | 3005 | |
43010659 PW |
3006 | if (move_one_task(target_rq, target_cpu, busiest_rq, |
3007 | sd, CPU_IDLE)) | |
48f24c4d IM |
3008 | schedstat_inc(sd, alb_pushed); |
3009 | else | |
3010 | schedstat_inc(sd, alb_failed); | |
3011 | } | |
39507451 | 3012 | spin_unlock(&target_rq->lock); |
1da177e4 LT |
3013 | } |
3014 | ||
46cb4b7c SS |
3015 | #ifdef CONFIG_NO_HZ |
3016 | static struct { | |
3017 | atomic_t load_balancer; | |
41a2d6cf | 3018 | cpumask_t cpu_mask; |
46cb4b7c SS |
3019 | } nohz ____cacheline_aligned = { |
3020 | .load_balancer = ATOMIC_INIT(-1), | |
3021 | .cpu_mask = CPU_MASK_NONE, | |
3022 | }; | |
3023 | ||
7835b98b | 3024 | /* |
46cb4b7c SS |
3025 | * This routine will try to nominate the ilb (idle load balancing) |
3026 | * owner among the cpus whose ticks are stopped. ilb owner will do the idle | |
3027 | * load balancing on behalf of all those cpus. If all the cpus in the system | |
3028 | * go into this tickless mode, then there will be no ilb owner (as there is | |
3029 | * no need for one) and all the cpus will sleep till the next wakeup event | |
3030 | * arrives... | |
3031 | * | |
3032 | * For the ilb owner, tick is not stopped. And this tick will be used | |
3033 | * for idle load balancing. ilb owner will still be part of | |
3034 | * nohz.cpu_mask.. | |
7835b98b | 3035 | * |
46cb4b7c SS |
3036 | * While stopping the tick, this cpu will become the ilb owner if there |
3037 | * is no other owner. And will be the owner till that cpu becomes busy | |
3038 | * or if all cpus in the system stop their ticks at which point | |
3039 | * there is no need for ilb owner. | |
3040 | * | |
3041 | * When the ilb owner becomes busy, it nominates another owner, during the | |
3042 | * next busy scheduler_tick() | |
3043 | */ | |
3044 | int select_nohz_load_balancer(int stop_tick) | |
3045 | { | |
3046 | int cpu = smp_processor_id(); | |
3047 | ||
3048 | if (stop_tick) { | |
3049 | cpu_set(cpu, nohz.cpu_mask); | |
3050 | cpu_rq(cpu)->in_nohz_recently = 1; | |
3051 | ||
3052 | /* | |
3053 | * If we are going offline and still the leader, give up! | |
3054 | */ | |
3055 | if (cpu_is_offline(cpu) && | |
3056 | atomic_read(&nohz.load_balancer) == cpu) { | |
3057 | if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu) | |
3058 | BUG(); | |
3059 | return 0; | |
3060 | } | |
3061 | ||
3062 | /* time for ilb owner also to sleep */ | |
3063 | if (cpus_weight(nohz.cpu_mask) == num_online_cpus()) { | |
3064 | if (atomic_read(&nohz.load_balancer) == cpu) | |
3065 | atomic_set(&nohz.load_balancer, -1); | |
3066 | return 0; | |
3067 | } | |
3068 | ||
3069 | if (atomic_read(&nohz.load_balancer) == -1) { | |
3070 | /* make me the ilb owner */ | |
3071 | if (atomic_cmpxchg(&nohz.load_balancer, -1, cpu) == -1) | |
3072 | return 1; | |
3073 | } else if (atomic_read(&nohz.load_balancer) == cpu) | |
3074 | return 1; | |
3075 | } else { | |
3076 | if (!cpu_isset(cpu, nohz.cpu_mask)) | |
3077 | return 0; | |
3078 | ||
3079 | cpu_clear(cpu, nohz.cpu_mask); | |
3080 | ||
3081 | if (atomic_read(&nohz.load_balancer) == cpu) | |
3082 | if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu) | |
3083 | BUG(); | |
3084 | } | |
3085 | return 0; | |
3086 | } | |
3087 | #endif | |
3088 | ||
3089 | static DEFINE_SPINLOCK(balancing); | |
3090 | ||
3091 | /* | |
7835b98b CL |
3092 | * It checks each scheduling domain to see if it is due to be balanced, |
3093 | * and initiates a balancing operation if so. | |
3094 | * | |
3095 | * Balancing parameters are set up in arch_init_sched_domains. | |
3096 | */ | |
a9957449 | 3097 | static void rebalance_domains(int cpu, enum cpu_idle_type idle) |
7835b98b | 3098 | { |
46cb4b7c SS |
3099 | int balance = 1; |
3100 | struct rq *rq = cpu_rq(cpu); | |
7835b98b CL |
3101 | unsigned long interval; |
3102 | struct sched_domain *sd; | |
46cb4b7c | 3103 | /* Earliest time when we have to do rebalance again */ |
c9819f45 | 3104 | unsigned long next_balance = jiffies + 60*HZ; |
f549da84 | 3105 | int update_next_balance = 0; |
1da177e4 | 3106 | |
46cb4b7c | 3107 | for_each_domain(cpu, sd) { |
1da177e4 LT |
3108 | if (!(sd->flags & SD_LOAD_BALANCE)) |
3109 | continue; | |
3110 | ||
3111 | interval = sd->balance_interval; | |
d15bcfdb | 3112 | if (idle != CPU_IDLE) |
1da177e4 LT |
3113 | interval *= sd->busy_factor; |
3114 | ||
3115 | /* scale ms to jiffies */ | |
3116 | interval = msecs_to_jiffies(interval); | |
3117 | if (unlikely(!interval)) | |
3118 | interval = 1; | |
dd41f596 IM |
3119 | if (interval > HZ*NR_CPUS/10) |
3120 | interval = HZ*NR_CPUS/10; | |
3121 | ||
1da177e4 | 3122 | |
08c183f3 CL |
3123 | if (sd->flags & SD_SERIALIZE) { |
3124 | if (!spin_trylock(&balancing)) | |
3125 | goto out; | |
3126 | } | |
3127 | ||
c9819f45 | 3128 | if (time_after_eq(jiffies, sd->last_balance + interval)) { |
46cb4b7c | 3129 | if (load_balance(cpu, rq, sd, idle, &balance)) { |
fa3b6ddc SS |
3130 | /* |
3131 | * We've pulled tasks over so either we're no | |
5969fe06 NP |
3132 | * longer idle, or one of our SMT siblings is |
3133 | * not idle. | |
3134 | */ | |
d15bcfdb | 3135 | idle = CPU_NOT_IDLE; |
1da177e4 | 3136 | } |
1bd77f2d | 3137 | sd->last_balance = jiffies; |
1da177e4 | 3138 | } |
08c183f3 CL |
3139 | if (sd->flags & SD_SERIALIZE) |
3140 | spin_unlock(&balancing); | |
3141 | out: | |
f549da84 | 3142 | if (time_after(next_balance, sd->last_balance + interval)) { |
c9819f45 | 3143 | next_balance = sd->last_balance + interval; |
f549da84 SS |
3144 | update_next_balance = 1; |
3145 | } | |
783609c6 SS |
3146 | |
3147 | /* | |
3148 | * Stop the load balance at this level. There is another | |
3149 | * CPU in our sched group which is doing load balancing more | |
3150 | * actively. | |
3151 | */ | |
3152 | if (!balance) | |
3153 | break; | |
1da177e4 | 3154 | } |
f549da84 SS |
3155 | |
3156 | /* | |
3157 | * next_balance will be updated only when there is a need. | |
3158 | * When the cpu is attached to null domain for ex, it will not be | |
3159 | * updated. | |
3160 | */ | |
3161 | if (likely(update_next_balance)) | |
3162 | rq->next_balance = next_balance; | |
46cb4b7c SS |
3163 | } |
3164 | ||
3165 | /* | |
3166 | * run_rebalance_domains is triggered when needed from the scheduler tick. | |
3167 | * In CONFIG_NO_HZ case, the idle load balance owner will do the | |
3168 | * rebalancing for all the cpus for whom scheduler ticks are stopped. | |
3169 | */ | |
3170 | static void run_rebalance_domains(struct softirq_action *h) | |
3171 | { | |
dd41f596 IM |
3172 | int this_cpu = smp_processor_id(); |
3173 | struct rq *this_rq = cpu_rq(this_cpu); | |
3174 | enum cpu_idle_type idle = this_rq->idle_at_tick ? | |
3175 | CPU_IDLE : CPU_NOT_IDLE; | |
46cb4b7c | 3176 | |
dd41f596 | 3177 | rebalance_domains(this_cpu, idle); |
46cb4b7c SS |
3178 | |
3179 | #ifdef CONFIG_NO_HZ | |
3180 | /* | |
3181 | * If this cpu is the owner for idle load balancing, then do the | |
3182 | * balancing on behalf of the other idle cpus whose ticks are | |
3183 | * stopped. | |
3184 | */ | |
dd41f596 IM |
3185 | if (this_rq->idle_at_tick && |
3186 | atomic_read(&nohz.load_balancer) == this_cpu) { | |
46cb4b7c SS |
3187 | cpumask_t cpus = nohz.cpu_mask; |
3188 | struct rq *rq; | |
3189 | int balance_cpu; | |
3190 | ||
dd41f596 | 3191 | cpu_clear(this_cpu, cpus); |
46cb4b7c SS |
3192 | for_each_cpu_mask(balance_cpu, cpus) { |
3193 | /* | |
3194 | * If this cpu gets work to do, stop the load balancing | |
3195 | * work being done for other cpus. Next load | |
3196 | * balancing owner will pick it up. | |
3197 | */ | |
3198 | if (need_resched()) | |
3199 | break; | |
3200 | ||
de0cf899 | 3201 | rebalance_domains(balance_cpu, CPU_IDLE); |
46cb4b7c SS |
3202 | |
3203 | rq = cpu_rq(balance_cpu); | |
dd41f596 IM |
3204 | if (time_after(this_rq->next_balance, rq->next_balance)) |
3205 | this_rq->next_balance = rq->next_balance; | |
46cb4b7c SS |
3206 | } |
3207 | } | |
3208 | #endif | |
3209 | } | |
3210 | ||
3211 | /* | |
3212 | * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing. | |
3213 | * | |
3214 | * In case of CONFIG_NO_HZ, this is the place where we nominate a new | |
3215 | * idle load balancing owner or decide to stop the periodic load balancing, | |
3216 | * if the whole system is idle. | |
3217 | */ | |
dd41f596 | 3218 | static inline void trigger_load_balance(struct rq *rq, int cpu) |
46cb4b7c | 3219 | { |
46cb4b7c SS |
3220 | #ifdef CONFIG_NO_HZ |
3221 | /* | |
3222 | * If we were in the nohz mode recently and busy at the current | |
3223 | * scheduler tick, then check if we need to nominate new idle | |
3224 | * load balancer. | |
3225 | */ | |
3226 | if (rq->in_nohz_recently && !rq->idle_at_tick) { | |
3227 | rq->in_nohz_recently = 0; | |
3228 | ||
3229 | if (atomic_read(&nohz.load_balancer) == cpu) { | |
3230 | cpu_clear(cpu, nohz.cpu_mask); | |
3231 | atomic_set(&nohz.load_balancer, -1); | |
3232 | } | |
3233 | ||
3234 | if (atomic_read(&nohz.load_balancer) == -1) { | |
3235 | /* | |
3236 | * simple selection for now: Nominate the | |
3237 | * first cpu in the nohz list to be the next | |
3238 | * ilb owner. | |
3239 | * | |
3240 | * TBD: Traverse the sched domains and nominate | |
3241 | * the nearest cpu in the nohz.cpu_mask. | |
3242 | */ | |
3243 | int ilb = first_cpu(nohz.cpu_mask); | |
3244 | ||
3245 | if (ilb != NR_CPUS) | |
3246 | resched_cpu(ilb); | |
3247 | } | |
3248 | } | |
3249 | ||
3250 | /* | |
3251 | * If this cpu is idle and doing idle load balancing for all the | |
3252 | * cpus with ticks stopped, is it time for that to stop? | |
3253 | */ | |
3254 | if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) == cpu && | |
3255 | cpus_weight(nohz.cpu_mask) == num_online_cpus()) { | |
3256 | resched_cpu(cpu); | |
3257 | return; | |
3258 | } | |
3259 | ||
3260 | /* | |
3261 | * If this cpu is idle and the idle load balancing is done by | |
3262 | * someone else, then no need raise the SCHED_SOFTIRQ | |
3263 | */ | |
3264 | if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) != cpu && | |
3265 | cpu_isset(cpu, nohz.cpu_mask)) | |
3266 | return; | |
3267 | #endif | |
3268 | if (time_after_eq(jiffies, rq->next_balance)) | |
3269 | raise_softirq(SCHED_SOFTIRQ); | |
1da177e4 | 3270 | } |
dd41f596 IM |
3271 | |
3272 | #else /* CONFIG_SMP */ | |
3273 | ||
1da177e4 LT |
3274 | /* |
3275 | * on UP we do not need to balance between CPUs: | |
3276 | */ | |
70b97a7f | 3277 | static inline void idle_balance(int cpu, struct rq *rq) |
1da177e4 LT |
3278 | { |
3279 | } | |
dd41f596 | 3280 | |
1da177e4 LT |
3281 | #endif |
3282 | ||
1da177e4 LT |
3283 | DEFINE_PER_CPU(struct kernel_stat, kstat); |
3284 | ||
3285 | EXPORT_PER_CPU_SYMBOL(kstat); | |
3286 | ||
3287 | /* | |
41b86e9c IM |
3288 | * Return p->sum_exec_runtime plus any more ns on the sched_clock |
3289 | * that have not yet been banked in case the task is currently running. | |
1da177e4 | 3290 | */ |
41b86e9c | 3291 | unsigned long long task_sched_runtime(struct task_struct *p) |
1da177e4 | 3292 | { |
1da177e4 | 3293 | unsigned long flags; |
41b86e9c IM |
3294 | u64 ns, delta_exec; |
3295 | struct rq *rq; | |
48f24c4d | 3296 | |
41b86e9c IM |
3297 | rq = task_rq_lock(p, &flags); |
3298 | ns = p->se.sum_exec_runtime; | |
051a1d1a | 3299 | if (task_current(rq, p)) { |
a8e504d2 IM |
3300 | update_rq_clock(rq); |
3301 | delta_exec = rq->clock - p->se.exec_start; | |
41b86e9c IM |
3302 | if ((s64)delta_exec > 0) |
3303 | ns += delta_exec; | |
3304 | } | |
3305 | task_rq_unlock(rq, &flags); | |
48f24c4d | 3306 | |
1da177e4 LT |
3307 | return ns; |
3308 | } | |
3309 | ||
1da177e4 LT |
3310 | /* |
3311 | * Account user cpu time to a process. | |
3312 | * @p: the process that the cpu time gets accounted to | |
1da177e4 LT |
3313 | * @cputime: the cpu time spent in user space since the last update |
3314 | */ | |
3315 | void account_user_time(struct task_struct *p, cputime_t cputime) | |
3316 | { | |
3317 | struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; | |
3318 | cputime64_t tmp; | |
3319 | ||
3320 | p->utime = cputime_add(p->utime, cputime); | |
3321 | ||
3322 | /* Add user time to cpustat. */ | |
3323 | tmp = cputime_to_cputime64(cputime); | |
3324 | if (TASK_NICE(p) > 0) | |
3325 | cpustat->nice = cputime64_add(cpustat->nice, tmp); | |
3326 | else | |
3327 | cpustat->user = cputime64_add(cpustat->user, tmp); | |
3328 | } | |
3329 | ||
94886b84 LV |
3330 | /* |
3331 | * Account guest cpu time to a process. | |
3332 | * @p: the process that the cpu time gets accounted to | |
3333 | * @cputime: the cpu time spent in virtual machine since the last update | |
3334 | */ | |
f7402e03 | 3335 | static void account_guest_time(struct task_struct *p, cputime_t cputime) |
94886b84 LV |
3336 | { |
3337 | cputime64_t tmp; | |
3338 | struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; | |
3339 | ||
3340 | tmp = cputime_to_cputime64(cputime); | |
3341 | ||
3342 | p->utime = cputime_add(p->utime, cputime); | |
3343 | p->gtime = cputime_add(p->gtime, cputime); | |
3344 | ||
3345 | cpustat->user = cputime64_add(cpustat->user, tmp); | |
3346 | cpustat->guest = cputime64_add(cpustat->guest, tmp); | |
3347 | } | |
3348 | ||
c66f08be MN |
3349 | /* |
3350 | * Account scaled user cpu time to a process. | |
3351 | * @p: the process that the cpu time gets accounted to | |
3352 | * @cputime: the cpu time spent in user space since the last update | |
3353 | */ | |
3354 | void account_user_time_scaled(struct task_struct *p, cputime_t cputime) | |
3355 | { | |
3356 | p->utimescaled = cputime_add(p->utimescaled, cputime); | |
3357 | } | |
3358 | ||
1da177e4 LT |
3359 | /* |
3360 | * Account system cpu time to a process. | |
3361 | * @p: the process that the cpu time gets accounted to | |
3362 | * @hardirq_offset: the offset to subtract from hardirq_count() | |
3363 | * @cputime: the cpu time spent in kernel space since the last update | |
3364 | */ | |
3365 | void account_system_time(struct task_struct *p, int hardirq_offset, | |
3366 | cputime_t cputime) | |
3367 | { | |
3368 | struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; | |
70b97a7f | 3369 | struct rq *rq = this_rq(); |
1da177e4 LT |
3370 | cputime64_t tmp; |
3371 | ||
9778385d CB |
3372 | if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) |
3373 | return account_guest_time(p, cputime); | |
94886b84 | 3374 | |
1da177e4 LT |
3375 | p->stime = cputime_add(p->stime, cputime); |
3376 | ||
3377 | /* Add system time to cpustat. */ | |
3378 | tmp = cputime_to_cputime64(cputime); | |
3379 | if (hardirq_count() - hardirq_offset) | |
3380 | cpustat->irq = cputime64_add(cpustat->irq, tmp); | |
3381 | else if (softirq_count()) | |
3382 | cpustat->softirq = cputime64_add(cpustat->softirq, tmp); | |
cfb52856 | 3383 | else if (p != rq->idle) |
1da177e4 | 3384 | cpustat->system = cputime64_add(cpustat->system, tmp); |
cfb52856 | 3385 | else if (atomic_read(&rq->nr_iowait) > 0) |
1da177e4 LT |
3386 | cpustat->iowait = cputime64_add(cpustat->iowait, tmp); |
3387 | else | |
3388 | cpustat->idle = cputime64_add(cpustat->idle, tmp); | |
3389 | /* Account for system time used */ | |
3390 | acct_update_integrals(p); | |
1da177e4 LT |
3391 | } |
3392 | ||
c66f08be MN |
3393 | /* |
3394 | * Account scaled system cpu time to a process. | |
3395 | * @p: the process that the cpu time gets accounted to | |
3396 | * @hardirq_offset: the offset to subtract from hardirq_count() | |
3397 | * @cputime: the cpu time spent in kernel space since the last update | |
3398 | */ | |
3399 | void account_system_time_scaled(struct task_struct *p, cputime_t cputime) | |
3400 | { | |
3401 | p->stimescaled = cputime_add(p->stimescaled, cputime); | |
3402 | } | |
3403 | ||
1da177e4 LT |
3404 | /* |
3405 | * Account for involuntary wait time. | |
3406 | * @p: the process from which the cpu time has been stolen | |
3407 | * @steal: the cpu time spent in involuntary wait | |
3408 | */ | |
3409 | void account_steal_time(struct task_struct *p, cputime_t steal) | |
3410 | { | |
3411 | struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; | |
3412 | cputime64_t tmp = cputime_to_cputime64(steal); | |
70b97a7f | 3413 | struct rq *rq = this_rq(); |
1da177e4 LT |
3414 | |
3415 | if (p == rq->idle) { | |
3416 | p->stime = cputime_add(p->stime, steal); | |
3417 | if (atomic_read(&rq->nr_iowait) > 0) | |
3418 | cpustat->iowait = cputime64_add(cpustat->iowait, tmp); | |
3419 | else | |
3420 | cpustat->idle = cputime64_add(cpustat->idle, tmp); | |
cfb52856 | 3421 | } else |
1da177e4 LT |
3422 | cpustat->steal = cputime64_add(cpustat->steal, tmp); |
3423 | } | |
3424 | ||
7835b98b CL |
3425 | /* |
3426 | * This function gets called by the timer code, with HZ frequency. | |
3427 | * We call it with interrupts disabled. | |
3428 | * | |
3429 | * It also gets called by the fork code, when changing the parent's | |
3430 | * timeslices. | |
3431 | */ | |
3432 | void scheduler_tick(void) | |
3433 | { | |
7835b98b CL |
3434 | int cpu = smp_processor_id(); |
3435 | struct rq *rq = cpu_rq(cpu); | |
dd41f596 | 3436 | struct task_struct *curr = rq->curr; |
529c7726 | 3437 | u64 next_tick = rq->tick_timestamp + TICK_NSEC; |
dd41f596 IM |
3438 | |
3439 | spin_lock(&rq->lock); | |
546fe3c9 | 3440 | __update_rq_clock(rq); |
529c7726 IM |
3441 | /* |
3442 | * Let rq->clock advance by at least TICK_NSEC: | |
3443 | */ | |
3444 | if (unlikely(rq->clock < next_tick)) | |
3445 | rq->clock = next_tick; | |
3446 | rq->tick_timestamp = rq->clock; | |
f1a438d8 | 3447 | update_cpu_load(rq); |
dd41f596 IM |
3448 | if (curr != rq->idle) /* FIXME: needed? */ |
3449 | curr->sched_class->task_tick(rq, curr); | |
dd41f596 | 3450 | spin_unlock(&rq->lock); |
7835b98b | 3451 | |
e418e1c2 | 3452 | #ifdef CONFIG_SMP |
dd41f596 IM |
3453 | rq->idle_at_tick = idle_cpu(cpu); |
3454 | trigger_load_balance(rq, cpu); | |
e418e1c2 | 3455 | #endif |
1da177e4 LT |
3456 | } |
3457 | ||
1da177e4 LT |
3458 | #if defined(CONFIG_PREEMPT) && defined(CONFIG_DEBUG_PREEMPT) |
3459 | ||
3460 | void fastcall add_preempt_count(int val) | |
3461 | { | |
3462 | /* | |
3463 | * Underflow? | |
3464 | */ | |
9a11b49a IM |
3465 | if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0))) |
3466 | return; | |
1da177e4 LT |
3467 | preempt_count() += val; |
3468 | /* | |
3469 | * Spinlock count overflowing soon? | |
3470 | */ | |
33859f7f MOS |
3471 | DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >= |
3472 | PREEMPT_MASK - 10); | |
1da177e4 LT |
3473 | } |
3474 | EXPORT_SYMBOL(add_preempt_count); | |
3475 | ||
3476 | void fastcall sub_preempt_count(int val) | |
3477 | { | |
3478 | /* | |
3479 | * Underflow? | |
3480 | */ | |
9a11b49a IM |
3481 | if (DEBUG_LOCKS_WARN_ON(val > preempt_count())) |
3482 | return; | |
1da177e4 LT |
3483 | /* |
3484 | * Is the spinlock portion underflowing? | |
3485 | */ | |
9a11b49a IM |
3486 | if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) && |
3487 | !(preempt_count() & PREEMPT_MASK))) | |
3488 | return; | |
3489 | ||
1da177e4 LT |
3490 | preempt_count() -= val; |
3491 | } | |
3492 | EXPORT_SYMBOL(sub_preempt_count); | |
3493 | ||
3494 | #endif | |
3495 | ||
3496 | /* | |
dd41f596 | 3497 | * Print scheduling while atomic bug: |
1da177e4 | 3498 | */ |
dd41f596 | 3499 | static noinline void __schedule_bug(struct task_struct *prev) |
1da177e4 | 3500 | { |
838225b4 SS |
3501 | struct pt_regs *regs = get_irq_regs(); |
3502 | ||
3503 | printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n", | |
3504 | prev->comm, prev->pid, preempt_count()); | |
3505 | ||
dd41f596 IM |
3506 | debug_show_held_locks(prev); |
3507 | if (irqs_disabled()) | |
3508 | print_irqtrace_events(prev); | |
838225b4 SS |
3509 | |
3510 | if (regs) | |
3511 | show_regs(regs); | |
3512 | else | |
3513 | dump_stack(); | |
dd41f596 | 3514 | } |
1da177e4 | 3515 | |
dd41f596 IM |
3516 | /* |
3517 | * Various schedule()-time debugging checks and statistics: | |
3518 | */ | |
3519 | static inline void schedule_debug(struct task_struct *prev) | |
3520 | { | |
1da177e4 | 3521 | /* |
41a2d6cf | 3522 | * Test if we are atomic. Since do_exit() needs to call into |
1da177e4 LT |
3523 | * schedule() atomically, we ignore that path for now. |
3524 | * Otherwise, whine if we are scheduling when we should not be. | |
3525 | */ | |
dd41f596 IM |
3526 | if (unlikely(in_atomic_preempt_off()) && unlikely(!prev->exit_state)) |
3527 | __schedule_bug(prev); | |
3528 | ||
1da177e4 LT |
3529 | profile_hit(SCHED_PROFILING, __builtin_return_address(0)); |
3530 | ||
2d72376b | 3531 | schedstat_inc(this_rq(), sched_count); |
b8efb561 IM |
3532 | #ifdef CONFIG_SCHEDSTATS |
3533 | if (unlikely(prev->lock_depth >= 0)) { | |
2d72376b IM |
3534 | schedstat_inc(this_rq(), bkl_count); |
3535 | schedstat_inc(prev, sched_info.bkl_count); | |
b8efb561 IM |
3536 | } |
3537 | #endif | |
dd41f596 IM |
3538 | } |
3539 | ||
3540 | /* | |
3541 | * Pick up the highest-prio task: | |
3542 | */ | |
3543 | static inline struct task_struct * | |
ff95f3df | 3544 | pick_next_task(struct rq *rq, struct task_struct *prev) |
dd41f596 | 3545 | { |
5522d5d5 | 3546 | const struct sched_class *class; |
dd41f596 | 3547 | struct task_struct *p; |
1da177e4 LT |
3548 | |
3549 | /* | |
dd41f596 IM |
3550 | * Optimization: we know that if all tasks are in |
3551 | * the fair class we can call that function directly: | |
1da177e4 | 3552 | */ |
dd41f596 | 3553 | if (likely(rq->nr_running == rq->cfs.nr_running)) { |
fb8d4724 | 3554 | p = fair_sched_class.pick_next_task(rq); |
dd41f596 IM |
3555 | if (likely(p)) |
3556 | return p; | |
1da177e4 LT |
3557 | } |
3558 | ||
dd41f596 IM |
3559 | class = sched_class_highest; |
3560 | for ( ; ; ) { | |
fb8d4724 | 3561 | p = class->pick_next_task(rq); |
dd41f596 IM |
3562 | if (p) |
3563 | return p; | |
3564 | /* | |
3565 | * Will never be NULL as the idle class always | |
3566 | * returns a non-NULL p: | |
3567 | */ | |
3568 | class = class->next; | |
3569 | } | |
3570 | } | |
1da177e4 | 3571 | |
dd41f596 IM |
3572 | /* |
3573 | * schedule() is the main scheduler function. | |
3574 | */ | |
3575 | asmlinkage void __sched schedule(void) | |
3576 | { | |
3577 | struct task_struct *prev, *next; | |
3578 | long *switch_count; | |
3579 | struct rq *rq; | |
dd41f596 IM |
3580 | int cpu; |
3581 | ||
3582 | need_resched: | |
3583 | preempt_disable(); | |
3584 | cpu = smp_processor_id(); | |
3585 | rq = cpu_rq(cpu); | |
3586 | rcu_qsctr_inc(cpu); | |
3587 | prev = rq->curr; | |
3588 | switch_count = &prev->nivcsw; | |
3589 | ||
3590 | release_kernel_lock(prev); | |
3591 | need_resched_nonpreemptible: | |
3592 | ||
3593 | schedule_debug(prev); | |
1da177e4 | 3594 | |
1e819950 IM |
3595 | /* |
3596 | * Do the rq-clock update outside the rq lock: | |
3597 | */ | |
3598 | local_irq_disable(); | |
c1b3da3e | 3599 | __update_rq_clock(rq); |
1e819950 IM |
3600 | spin_lock(&rq->lock); |
3601 | clear_tsk_need_resched(prev); | |
1da177e4 | 3602 | |
1da177e4 | 3603 | if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) { |
1da177e4 | 3604 | if (unlikely((prev->state & TASK_INTERRUPTIBLE) && |
dd41f596 | 3605 | unlikely(signal_pending(prev)))) { |
1da177e4 | 3606 | prev->state = TASK_RUNNING; |
dd41f596 | 3607 | } else { |
2e1cb74a | 3608 | deactivate_task(rq, prev, 1); |
1da177e4 | 3609 | } |
dd41f596 | 3610 | switch_count = &prev->nvcsw; |
1da177e4 LT |
3611 | } |
3612 | ||
f65eda4f SR |
3613 | schedule_balance_rt(rq, prev); |
3614 | ||
dd41f596 | 3615 | if (unlikely(!rq->nr_running)) |
1da177e4 | 3616 | idle_balance(cpu, rq); |
1da177e4 | 3617 | |
31ee529c | 3618 | prev->sched_class->put_prev_task(rq, prev); |
ff95f3df | 3619 | next = pick_next_task(rq, prev); |
1da177e4 LT |
3620 | |
3621 | sched_info_switch(prev, next); | |
dd41f596 | 3622 | |
1da177e4 | 3623 | if (likely(prev != next)) { |
1da177e4 LT |
3624 | rq->nr_switches++; |
3625 | rq->curr = next; | |
3626 | ++*switch_count; | |
3627 | ||
dd41f596 | 3628 | context_switch(rq, prev, next); /* unlocks the rq */ |
1da177e4 LT |
3629 | } else |
3630 | spin_unlock_irq(&rq->lock); | |
3631 | ||
dd41f596 IM |
3632 | if (unlikely(reacquire_kernel_lock(current) < 0)) { |
3633 | cpu = smp_processor_id(); | |
3634 | rq = cpu_rq(cpu); | |
1da177e4 | 3635 | goto need_resched_nonpreemptible; |
dd41f596 | 3636 | } |
1da177e4 LT |
3637 | preempt_enable_no_resched(); |
3638 | if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) | |
3639 | goto need_resched; | |
3640 | } | |
1da177e4 LT |
3641 | EXPORT_SYMBOL(schedule); |
3642 | ||
3643 | #ifdef CONFIG_PREEMPT | |
3644 | /* | |
2ed6e34f | 3645 | * this is the entry point to schedule() from in-kernel preemption |
41a2d6cf | 3646 | * off of preempt_enable. Kernel preemptions off return from interrupt |
1da177e4 LT |
3647 | * occur there and call schedule directly. |
3648 | */ | |
3649 | asmlinkage void __sched preempt_schedule(void) | |
3650 | { | |
3651 | struct thread_info *ti = current_thread_info(); | |
3652 | #ifdef CONFIG_PREEMPT_BKL | |
3653 | struct task_struct *task = current; | |
3654 | int saved_lock_depth; | |
3655 | #endif | |
3656 | /* | |
3657 | * If there is a non-zero preempt_count or interrupts are disabled, | |
41a2d6cf | 3658 | * we do not want to preempt the current task. Just return.. |
1da177e4 | 3659 | */ |
beed33a8 | 3660 | if (likely(ti->preempt_count || irqs_disabled())) |
1da177e4 LT |
3661 | return; |
3662 | ||
3a5c359a AK |
3663 | do { |
3664 | add_preempt_count(PREEMPT_ACTIVE); | |
3665 | ||
3666 | /* | |
3667 | * We keep the big kernel semaphore locked, but we | |
3668 | * clear ->lock_depth so that schedule() doesnt | |
3669 | * auto-release the semaphore: | |
3670 | */ | |
1da177e4 | 3671 | #ifdef CONFIG_PREEMPT_BKL |
3a5c359a AK |
3672 | saved_lock_depth = task->lock_depth; |
3673 | task->lock_depth = -1; | |
1da177e4 | 3674 | #endif |
3a5c359a | 3675 | schedule(); |
1da177e4 | 3676 | #ifdef CONFIG_PREEMPT_BKL |
3a5c359a | 3677 | task->lock_depth = saved_lock_depth; |
1da177e4 | 3678 | #endif |
3a5c359a | 3679 | sub_preempt_count(PREEMPT_ACTIVE); |
1da177e4 | 3680 | |
3a5c359a AK |
3681 | /* |
3682 | * Check again in case we missed a preemption opportunity | |
3683 | * between schedule and now. | |
3684 | */ | |
3685 | barrier(); | |
3686 | } while (unlikely(test_thread_flag(TIF_NEED_RESCHED))); | |
1da177e4 | 3687 | } |
1da177e4 LT |
3688 | EXPORT_SYMBOL(preempt_schedule); |
3689 | ||
3690 | /* | |
2ed6e34f | 3691 | * this is the entry point to schedule() from kernel preemption |
1da177e4 LT |
3692 | * off of irq context. |
3693 | * Note, that this is called and return with irqs disabled. This will | |
3694 | * protect us against recursive calling from irq. | |
3695 | */ | |
3696 | asmlinkage void __sched preempt_schedule_irq(void) | |
3697 | { | |
3698 | struct thread_info *ti = current_thread_info(); | |
3699 | #ifdef CONFIG_PREEMPT_BKL | |
3700 | struct task_struct *task = current; | |
3701 | int saved_lock_depth; | |
3702 | #endif | |
2ed6e34f | 3703 | /* Catch callers which need to be fixed */ |
1da177e4 LT |
3704 | BUG_ON(ti->preempt_count || !irqs_disabled()); |
3705 | ||
3a5c359a AK |
3706 | do { |
3707 | add_preempt_count(PREEMPT_ACTIVE); | |
3708 | ||
3709 | /* | |
3710 | * We keep the big kernel semaphore locked, but we | |
3711 | * clear ->lock_depth so that schedule() doesnt | |
3712 | * auto-release the semaphore: | |
3713 | */ | |
1da177e4 | 3714 | #ifdef CONFIG_PREEMPT_BKL |
3a5c359a AK |
3715 | saved_lock_depth = task->lock_depth; |
3716 | task->lock_depth = -1; | |
1da177e4 | 3717 | #endif |
3a5c359a AK |
3718 | local_irq_enable(); |
3719 | schedule(); | |
3720 | local_irq_disable(); | |
1da177e4 | 3721 | #ifdef CONFIG_PREEMPT_BKL |
3a5c359a | 3722 | task->lock_depth = saved_lock_depth; |
1da177e4 | 3723 | #endif |
3a5c359a | 3724 | sub_preempt_count(PREEMPT_ACTIVE); |
1da177e4 | 3725 | |
3a5c359a AK |
3726 | /* |
3727 | * Check again in case we missed a preemption opportunity | |
3728 | * between schedule and now. | |
3729 | */ | |
3730 | barrier(); | |
3731 | } while (unlikely(test_thread_flag(TIF_NEED_RESCHED))); | |
1da177e4 LT |
3732 | } |
3733 | ||
3734 | #endif /* CONFIG_PREEMPT */ | |
3735 | ||
95cdf3b7 IM |
3736 | int default_wake_function(wait_queue_t *curr, unsigned mode, int sync, |
3737 | void *key) | |
1da177e4 | 3738 | { |
48f24c4d | 3739 | return try_to_wake_up(curr->private, mode, sync); |
1da177e4 | 3740 | } |
1da177e4 LT |
3741 | EXPORT_SYMBOL(default_wake_function); |
3742 | ||
3743 | /* | |
41a2d6cf IM |
3744 | * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just |
3745 | * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve | |
1da177e4 LT |
3746 | * number) then we wake all the non-exclusive tasks and one exclusive task. |
3747 | * | |
3748 | * There are circumstances in which we can try to wake a task which has already | |
41a2d6cf | 3749 | * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns |
1da177e4 LT |
3750 | * zero in this (rare) case, and we handle it by continuing to scan the queue. |
3751 | */ | |
3752 | static void __wake_up_common(wait_queue_head_t *q, unsigned int mode, | |
3753 | int nr_exclusive, int sync, void *key) | |
3754 | { | |
2e45874c | 3755 | wait_queue_t *curr, *next; |
1da177e4 | 3756 | |
2e45874c | 3757 | list_for_each_entry_safe(curr, next, &q->task_list, task_list) { |
48f24c4d IM |
3758 | unsigned flags = curr->flags; |
3759 | ||
1da177e4 | 3760 | if (curr->func(curr, mode, sync, key) && |
48f24c4d | 3761 | (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive) |
1da177e4 LT |
3762 | break; |
3763 | } | |
3764 | } | |
3765 | ||
3766 | /** | |
3767 | * __wake_up - wake up threads blocked on a waitqueue. | |
3768 | * @q: the waitqueue | |
3769 | * @mode: which threads | |
3770 | * @nr_exclusive: how many wake-one or wake-many threads to wake up | |
67be2dd1 | 3771 | * @key: is directly passed to the wakeup function |
1da177e4 LT |
3772 | */ |
3773 | void fastcall __wake_up(wait_queue_head_t *q, unsigned int mode, | |
95cdf3b7 | 3774 | int nr_exclusive, void *key) |
1da177e4 LT |
3775 | { |
3776 | unsigned long flags; | |
3777 | ||
3778 | spin_lock_irqsave(&q->lock, flags); | |
3779 | __wake_up_common(q, mode, nr_exclusive, 0, key); | |
3780 | spin_unlock_irqrestore(&q->lock, flags); | |
3781 | } | |
1da177e4 LT |
3782 | EXPORT_SYMBOL(__wake_up); |
3783 | ||
3784 | /* | |
3785 | * Same as __wake_up but called with the spinlock in wait_queue_head_t held. | |
3786 | */ | |
3787 | void fastcall __wake_up_locked(wait_queue_head_t *q, unsigned int mode) | |
3788 | { | |
3789 | __wake_up_common(q, mode, 1, 0, NULL); | |
3790 | } | |
3791 | ||
3792 | /** | |
67be2dd1 | 3793 | * __wake_up_sync - wake up threads blocked on a waitqueue. |
1da177e4 LT |
3794 | * @q: the waitqueue |
3795 | * @mode: which threads | |
3796 | * @nr_exclusive: how many wake-one or wake-many threads to wake up | |
3797 | * | |
3798 | * The sync wakeup differs that the waker knows that it will schedule | |
3799 | * away soon, so while the target thread will be woken up, it will not | |
3800 | * be migrated to another CPU - ie. the two threads are 'synchronized' | |
3801 | * with each other. This can prevent needless bouncing between CPUs. | |
3802 | * | |
3803 | * On UP it can prevent extra preemption. | |
3804 | */ | |
95cdf3b7 IM |
3805 | void fastcall |
3806 | __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive) | |
1da177e4 LT |
3807 | { |
3808 | unsigned long flags; | |
3809 | int sync = 1; | |
3810 | ||
3811 | if (unlikely(!q)) | |
3812 | return; | |
3813 | ||
3814 | if (unlikely(!nr_exclusive)) | |
3815 | sync = 0; | |
3816 | ||
3817 | spin_lock_irqsave(&q->lock, flags); | |
3818 | __wake_up_common(q, mode, nr_exclusive, sync, NULL); | |
3819 | spin_unlock_irqrestore(&q->lock, flags); | |
3820 | } | |
3821 | EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */ | |
3822 | ||
b15136e9 | 3823 | void complete(struct completion *x) |
1da177e4 LT |
3824 | { |
3825 | unsigned long flags; | |
3826 | ||
3827 | spin_lock_irqsave(&x->wait.lock, flags); | |
3828 | x->done++; | |
3829 | __wake_up_common(&x->wait, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, | |
3830 | 1, 0, NULL); | |
3831 | spin_unlock_irqrestore(&x->wait.lock, flags); | |
3832 | } | |
3833 | EXPORT_SYMBOL(complete); | |
3834 | ||
b15136e9 | 3835 | void complete_all(struct completion *x) |
1da177e4 LT |
3836 | { |
3837 | unsigned long flags; | |
3838 | ||
3839 | spin_lock_irqsave(&x->wait.lock, flags); | |
3840 | x->done += UINT_MAX/2; | |
3841 | __wake_up_common(&x->wait, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, | |
3842 | 0, 0, NULL); | |
3843 | spin_unlock_irqrestore(&x->wait.lock, flags); | |
3844 | } | |
3845 | EXPORT_SYMBOL(complete_all); | |
3846 | ||
8cbbe86d AK |
3847 | static inline long __sched |
3848 | do_wait_for_common(struct completion *x, long timeout, int state) | |
1da177e4 | 3849 | { |
1da177e4 LT |
3850 | if (!x->done) { |
3851 | DECLARE_WAITQUEUE(wait, current); | |
3852 | ||
3853 | wait.flags |= WQ_FLAG_EXCLUSIVE; | |
3854 | __add_wait_queue_tail(&x->wait, &wait); | |
3855 | do { | |
8cbbe86d AK |
3856 | if (state == TASK_INTERRUPTIBLE && |
3857 | signal_pending(current)) { | |
3858 | __remove_wait_queue(&x->wait, &wait); | |
3859 | return -ERESTARTSYS; | |
3860 | } | |
3861 | __set_current_state(state); | |
1da177e4 LT |
3862 | spin_unlock_irq(&x->wait.lock); |
3863 | timeout = schedule_timeout(timeout); | |
3864 | spin_lock_irq(&x->wait.lock); | |
3865 | if (!timeout) { | |
3866 | __remove_wait_queue(&x->wait, &wait); | |
8cbbe86d | 3867 | return timeout; |
1da177e4 LT |
3868 | } |
3869 | } while (!x->done); | |
3870 | __remove_wait_queue(&x->wait, &wait); | |
3871 | } | |
3872 | x->done--; | |
1da177e4 LT |
3873 | return timeout; |
3874 | } | |
1da177e4 | 3875 | |
8cbbe86d AK |
3876 | static long __sched |
3877 | wait_for_common(struct completion *x, long timeout, int state) | |
1da177e4 | 3878 | { |
1da177e4 LT |
3879 | might_sleep(); |
3880 | ||
3881 | spin_lock_irq(&x->wait.lock); | |
8cbbe86d | 3882 | timeout = do_wait_for_common(x, timeout, state); |
1da177e4 | 3883 | spin_unlock_irq(&x->wait.lock); |
8cbbe86d AK |
3884 | return timeout; |
3885 | } | |
1da177e4 | 3886 | |
b15136e9 | 3887 | void __sched wait_for_completion(struct completion *x) |
8cbbe86d AK |
3888 | { |
3889 | wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE); | |
1da177e4 | 3890 | } |
8cbbe86d | 3891 | EXPORT_SYMBOL(wait_for_completion); |
1da177e4 | 3892 | |
b15136e9 | 3893 | unsigned long __sched |
8cbbe86d | 3894 | wait_for_completion_timeout(struct completion *x, unsigned long timeout) |
1da177e4 | 3895 | { |
8cbbe86d | 3896 | return wait_for_common(x, timeout, TASK_UNINTERRUPTIBLE); |
1da177e4 | 3897 | } |
8cbbe86d | 3898 | EXPORT_SYMBOL(wait_for_completion_timeout); |
1da177e4 | 3899 | |
8cbbe86d | 3900 | int __sched wait_for_completion_interruptible(struct completion *x) |
0fec171c | 3901 | { |
51e97990 AK |
3902 | long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_INTERRUPTIBLE); |
3903 | if (t == -ERESTARTSYS) | |
3904 | return t; | |
3905 | return 0; | |
0fec171c | 3906 | } |
8cbbe86d | 3907 | EXPORT_SYMBOL(wait_for_completion_interruptible); |
1da177e4 | 3908 | |
b15136e9 | 3909 | unsigned long __sched |
8cbbe86d AK |
3910 | wait_for_completion_interruptible_timeout(struct completion *x, |
3911 | unsigned long timeout) | |
0fec171c | 3912 | { |
8cbbe86d | 3913 | return wait_for_common(x, timeout, TASK_INTERRUPTIBLE); |
0fec171c | 3914 | } |
8cbbe86d | 3915 | EXPORT_SYMBOL(wait_for_completion_interruptible_timeout); |
1da177e4 | 3916 | |
8cbbe86d AK |
3917 | static long __sched |
3918 | sleep_on_common(wait_queue_head_t *q, int state, long timeout) | |
1da177e4 | 3919 | { |
0fec171c IM |
3920 | unsigned long flags; |
3921 | wait_queue_t wait; | |
3922 | ||
3923 | init_waitqueue_entry(&wait, current); | |
1da177e4 | 3924 | |
8cbbe86d | 3925 | __set_current_state(state); |
1da177e4 | 3926 | |
8cbbe86d AK |
3927 | spin_lock_irqsave(&q->lock, flags); |
3928 | __add_wait_queue(q, &wait); | |
3929 | spin_unlock(&q->lock); | |
3930 | timeout = schedule_timeout(timeout); | |
3931 | spin_lock_irq(&q->lock); | |
3932 | __remove_wait_queue(q, &wait); | |
3933 | spin_unlock_irqrestore(&q->lock, flags); | |
3934 | ||
3935 | return timeout; | |
3936 | } | |
3937 | ||
3938 | void __sched interruptible_sleep_on(wait_queue_head_t *q) | |
3939 | { | |
3940 | sleep_on_common(q, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); | |
1da177e4 | 3941 | } |
1da177e4 LT |
3942 | EXPORT_SYMBOL(interruptible_sleep_on); |
3943 | ||
0fec171c | 3944 | long __sched |
95cdf3b7 | 3945 | interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout) |
1da177e4 | 3946 | { |
8cbbe86d | 3947 | return sleep_on_common(q, TASK_INTERRUPTIBLE, timeout); |
1da177e4 | 3948 | } |
1da177e4 LT |
3949 | EXPORT_SYMBOL(interruptible_sleep_on_timeout); |
3950 | ||
0fec171c | 3951 | void __sched sleep_on(wait_queue_head_t *q) |
1da177e4 | 3952 | { |
8cbbe86d | 3953 | sleep_on_common(q, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); |
1da177e4 | 3954 | } |
1da177e4 LT |
3955 | EXPORT_SYMBOL(sleep_on); |
3956 | ||
0fec171c | 3957 | long __sched sleep_on_timeout(wait_queue_head_t *q, long timeout) |
1da177e4 | 3958 | { |
8cbbe86d | 3959 | return sleep_on_common(q, TASK_UNINTERRUPTIBLE, timeout); |
1da177e4 | 3960 | } |
1da177e4 LT |
3961 | EXPORT_SYMBOL(sleep_on_timeout); |
3962 | ||
b29739f9 IM |
3963 | #ifdef CONFIG_RT_MUTEXES |
3964 | ||
3965 | /* | |
3966 | * rt_mutex_setprio - set the current priority of a task | |
3967 | * @p: task | |
3968 | * @prio: prio value (kernel-internal form) | |
3969 | * | |
3970 | * This function changes the 'effective' priority of a task. It does | |
3971 | * not touch ->normal_prio like __setscheduler(). | |
3972 | * | |
3973 | * Used by the rt_mutex code to implement priority inheritance logic. | |
3974 | */ | |
36c8b586 | 3975 | void rt_mutex_setprio(struct task_struct *p, int prio) |
b29739f9 IM |
3976 | { |
3977 | unsigned long flags; | |
83b699ed | 3978 | int oldprio, on_rq, running; |
70b97a7f | 3979 | struct rq *rq; |
b29739f9 IM |
3980 | |
3981 | BUG_ON(prio < 0 || prio > MAX_PRIO); | |
3982 | ||
3983 | rq = task_rq_lock(p, &flags); | |
a8e504d2 | 3984 | update_rq_clock(rq); |
b29739f9 | 3985 | |
d5f9f942 | 3986 | oldprio = p->prio; |
dd41f596 | 3987 | on_rq = p->se.on_rq; |
051a1d1a | 3988 | running = task_current(rq, p); |
83b699ed | 3989 | if (on_rq) { |
69be72c1 | 3990 | dequeue_task(rq, p, 0); |
83b699ed SV |
3991 | if (running) |
3992 | p->sched_class->put_prev_task(rq, p); | |
3993 | } | |
dd41f596 IM |
3994 | |
3995 | if (rt_prio(prio)) | |
3996 | p->sched_class = &rt_sched_class; | |
3997 | else | |
3998 | p->sched_class = &fair_sched_class; | |
3999 | ||
b29739f9 IM |
4000 | p->prio = prio; |
4001 | ||
dd41f596 | 4002 | if (on_rq) { |
83b699ed SV |
4003 | if (running) |
4004 | p->sched_class->set_curr_task(rq); | |
8159f87e | 4005 | enqueue_task(rq, p, 0); |
b29739f9 IM |
4006 | /* |
4007 | * Reschedule if we are currently running on this runqueue and | |
d5f9f942 AM |
4008 | * our priority decreased, or if we are not currently running on |
4009 | * this runqueue and our priority is higher than the current's | |
b29739f9 | 4010 | */ |
83b699ed | 4011 | if (running) { |
d5f9f942 AM |
4012 | if (p->prio > oldprio) |
4013 | resched_task(rq->curr); | |
dd41f596 IM |
4014 | } else { |
4015 | check_preempt_curr(rq, p); | |
4016 | } | |
b29739f9 IM |
4017 | } |
4018 | task_rq_unlock(rq, &flags); | |
4019 | } | |
4020 | ||
4021 | #endif | |
4022 | ||
36c8b586 | 4023 | void set_user_nice(struct task_struct *p, long nice) |
1da177e4 | 4024 | { |
dd41f596 | 4025 | int old_prio, delta, on_rq; |
1da177e4 | 4026 | unsigned long flags; |
70b97a7f | 4027 | struct rq *rq; |
1da177e4 LT |
4028 | |
4029 | if (TASK_NICE(p) == nice || nice < -20 || nice > 19) | |
4030 | return; | |
4031 | /* | |
4032 | * We have to be careful, if called from sys_setpriority(), | |
4033 | * the task might be in the middle of scheduling on another CPU. | |
4034 | */ | |
4035 | rq = task_rq_lock(p, &flags); | |
a8e504d2 | 4036 | update_rq_clock(rq); |
1da177e4 LT |
4037 | /* |
4038 | * The RT priorities are set via sched_setscheduler(), but we still | |
4039 | * allow the 'normal' nice value to be set - but as expected | |
4040 | * it wont have any effect on scheduling until the task is | |
dd41f596 | 4041 | * SCHED_FIFO/SCHED_RR: |
1da177e4 | 4042 | */ |
e05606d3 | 4043 | if (task_has_rt_policy(p)) { |
1da177e4 LT |
4044 | p->static_prio = NICE_TO_PRIO(nice); |
4045 | goto out_unlock; | |
4046 | } | |
dd41f596 | 4047 | on_rq = p->se.on_rq; |
58e2d4ca | 4048 | if (on_rq) |
69be72c1 | 4049 | dequeue_task(rq, p, 0); |
1da177e4 | 4050 | |
1da177e4 | 4051 | p->static_prio = NICE_TO_PRIO(nice); |
2dd73a4f | 4052 | set_load_weight(p); |
b29739f9 IM |
4053 | old_prio = p->prio; |
4054 | p->prio = effective_prio(p); | |
4055 | delta = p->prio - old_prio; | |
1da177e4 | 4056 | |
dd41f596 | 4057 | if (on_rq) { |
8159f87e | 4058 | enqueue_task(rq, p, 0); |
1da177e4 | 4059 | /* |
d5f9f942 AM |
4060 | * If the task increased its priority or is running and |
4061 | * lowered its priority, then reschedule its CPU: | |
1da177e4 | 4062 | */ |
d5f9f942 | 4063 | if (delta < 0 || (delta > 0 && task_running(rq, p))) |
1da177e4 LT |
4064 | resched_task(rq->curr); |
4065 | } | |
4066 | out_unlock: | |
4067 | task_rq_unlock(rq, &flags); | |
4068 | } | |
1da177e4 LT |
4069 | EXPORT_SYMBOL(set_user_nice); |
4070 | ||
e43379f1 MM |
4071 | /* |
4072 | * can_nice - check if a task can reduce its nice value | |
4073 | * @p: task | |
4074 | * @nice: nice value | |
4075 | */ | |
36c8b586 | 4076 | int can_nice(const struct task_struct *p, const int nice) |
e43379f1 | 4077 | { |
024f4747 MM |
4078 | /* convert nice value [19,-20] to rlimit style value [1,40] */ |
4079 | int nice_rlim = 20 - nice; | |
48f24c4d | 4080 | |
e43379f1 MM |
4081 | return (nice_rlim <= p->signal->rlim[RLIMIT_NICE].rlim_cur || |
4082 | capable(CAP_SYS_NICE)); | |
4083 | } | |
4084 | ||
1da177e4 LT |
4085 | #ifdef __ARCH_WANT_SYS_NICE |
4086 | ||
4087 | /* | |
4088 | * sys_nice - change the priority of the current process. | |
4089 | * @increment: priority increment | |
4090 | * | |
4091 | * sys_setpriority is a more generic, but much slower function that | |
4092 | * does similar things. | |
4093 | */ | |
4094 | asmlinkage long sys_nice(int increment) | |
4095 | { | |
48f24c4d | 4096 | long nice, retval; |
1da177e4 LT |
4097 | |
4098 | /* | |
4099 | * Setpriority might change our priority at the same moment. | |
4100 | * We don't have to worry. Conceptually one call occurs first | |
4101 | * and we have a single winner. | |
4102 | */ | |
e43379f1 MM |
4103 | if (increment < -40) |
4104 | increment = -40; | |
1da177e4 LT |
4105 | if (increment > 40) |
4106 | increment = 40; | |
4107 | ||
4108 | nice = PRIO_TO_NICE(current->static_prio) + increment; | |
4109 | if (nice < -20) | |
4110 | nice = -20; | |
4111 | if (nice > 19) | |
4112 | nice = 19; | |
4113 | ||
e43379f1 MM |
4114 | if (increment < 0 && !can_nice(current, nice)) |
4115 | return -EPERM; | |
4116 | ||
1da177e4 LT |
4117 | retval = security_task_setnice(current, nice); |
4118 | if (retval) | |
4119 | return retval; | |
4120 | ||
4121 | set_user_nice(current, nice); | |
4122 | return 0; | |
4123 | } | |
4124 | ||
4125 | #endif | |
4126 | ||
4127 | /** | |
4128 | * task_prio - return the priority value of a given task. | |
4129 | * @p: the task in question. | |
4130 | * | |
4131 | * This is the priority value as seen by users in /proc. | |
4132 | * RT tasks are offset by -200. Normal tasks are centered | |
4133 | * around 0, value goes from -16 to +15. | |
4134 | */ | |
36c8b586 | 4135 | int task_prio(const struct task_struct *p) |
1da177e4 LT |
4136 | { |
4137 | return p->prio - MAX_RT_PRIO; | |
4138 | } | |
4139 | ||
4140 | /** | |
4141 | * task_nice - return the nice value of a given task. | |
4142 | * @p: the task in question. | |
4143 | */ | |
36c8b586 | 4144 | int task_nice(const struct task_struct *p) |
1da177e4 LT |
4145 | { |
4146 | return TASK_NICE(p); | |
4147 | } | |
1da177e4 | 4148 | EXPORT_SYMBOL_GPL(task_nice); |
1da177e4 LT |
4149 | |
4150 | /** | |
4151 | * idle_cpu - is a given cpu idle currently? | |
4152 | * @cpu: the processor in question. | |
4153 | */ | |
4154 | int idle_cpu(int cpu) | |
4155 | { | |
4156 | return cpu_curr(cpu) == cpu_rq(cpu)->idle; | |
4157 | } | |
4158 | ||
1da177e4 LT |
4159 | /** |
4160 | * idle_task - return the idle task for a given cpu. | |
4161 | * @cpu: the processor in question. | |
4162 | */ | |
36c8b586 | 4163 | struct task_struct *idle_task(int cpu) |
1da177e4 LT |
4164 | { |
4165 | return cpu_rq(cpu)->idle; | |
4166 | } | |
4167 | ||
4168 | /** | |
4169 | * find_process_by_pid - find a process with a matching PID value. | |
4170 | * @pid: the pid in question. | |
4171 | */ | |
a9957449 | 4172 | static struct task_struct *find_process_by_pid(pid_t pid) |
1da177e4 | 4173 | { |
228ebcbe | 4174 | return pid ? find_task_by_vpid(pid) : current; |
1da177e4 LT |
4175 | } |
4176 | ||
4177 | /* Actually do priority change: must hold rq lock. */ | |
dd41f596 IM |
4178 | static void |
4179 | __setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio) | |
1da177e4 | 4180 | { |
dd41f596 | 4181 | BUG_ON(p->se.on_rq); |
48f24c4d | 4182 | |
1da177e4 | 4183 | p->policy = policy; |
dd41f596 IM |
4184 | switch (p->policy) { |
4185 | case SCHED_NORMAL: | |
4186 | case SCHED_BATCH: | |
4187 | case SCHED_IDLE: | |
4188 | p->sched_class = &fair_sched_class; | |
4189 | break; | |
4190 | case SCHED_FIFO: | |
4191 | case SCHED_RR: | |
4192 | p->sched_class = &rt_sched_class; | |
4193 | break; | |
4194 | } | |
4195 | ||
1da177e4 | 4196 | p->rt_priority = prio; |
b29739f9 IM |
4197 | p->normal_prio = normal_prio(p); |
4198 | /* we are holding p->pi_lock already */ | |
4199 | p->prio = rt_mutex_getprio(p); | |
2dd73a4f | 4200 | set_load_weight(p); |
1da177e4 LT |
4201 | } |
4202 | ||
4203 | /** | |
72fd4a35 | 4204 | * sched_setscheduler - change the scheduling policy and/or RT priority of a thread. |
1da177e4 LT |
4205 | * @p: the task in question. |
4206 | * @policy: new policy. | |
4207 | * @param: structure containing the new RT priority. | |
5fe1d75f | 4208 | * |
72fd4a35 | 4209 | * NOTE that the task may be already dead. |
1da177e4 | 4210 | */ |
95cdf3b7 IM |
4211 | int sched_setscheduler(struct task_struct *p, int policy, |
4212 | struct sched_param *param) | |
1da177e4 | 4213 | { |
83b699ed | 4214 | int retval, oldprio, oldpolicy = -1, on_rq, running; |
1da177e4 | 4215 | unsigned long flags; |
70b97a7f | 4216 | struct rq *rq; |
1da177e4 | 4217 | |
66e5393a SR |
4218 | /* may grab non-irq protected spin_locks */ |
4219 | BUG_ON(in_interrupt()); | |
1da177e4 LT |
4220 | recheck: |
4221 | /* double check policy once rq lock held */ | |
4222 | if (policy < 0) | |
4223 | policy = oldpolicy = p->policy; | |
4224 | else if (policy != SCHED_FIFO && policy != SCHED_RR && | |
dd41f596 IM |
4225 | policy != SCHED_NORMAL && policy != SCHED_BATCH && |
4226 | policy != SCHED_IDLE) | |
b0a9499c | 4227 | return -EINVAL; |
1da177e4 LT |
4228 | /* |
4229 | * Valid priorities for SCHED_FIFO and SCHED_RR are | |
dd41f596 IM |
4230 | * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL, |
4231 | * SCHED_BATCH and SCHED_IDLE is 0. | |
1da177e4 LT |
4232 | */ |
4233 | if (param->sched_priority < 0 || | |
95cdf3b7 | 4234 | (p->mm && param->sched_priority > MAX_USER_RT_PRIO-1) || |
d46523ea | 4235 | (!p->mm && param->sched_priority > MAX_RT_PRIO-1)) |
1da177e4 | 4236 | return -EINVAL; |
e05606d3 | 4237 | if (rt_policy(policy) != (param->sched_priority != 0)) |
1da177e4 LT |
4238 | return -EINVAL; |
4239 | ||
37e4ab3f OC |
4240 | /* |
4241 | * Allow unprivileged RT tasks to decrease priority: | |
4242 | */ | |
4243 | if (!capable(CAP_SYS_NICE)) { | |
e05606d3 | 4244 | if (rt_policy(policy)) { |
8dc3e909 | 4245 | unsigned long rlim_rtprio; |
8dc3e909 ON |
4246 | |
4247 | if (!lock_task_sighand(p, &flags)) | |
4248 | return -ESRCH; | |
4249 | rlim_rtprio = p->signal->rlim[RLIMIT_RTPRIO].rlim_cur; | |
4250 | unlock_task_sighand(p, &flags); | |
4251 | ||
4252 | /* can't set/change the rt policy */ | |
4253 | if (policy != p->policy && !rlim_rtprio) | |
4254 | return -EPERM; | |
4255 | ||
4256 | /* can't increase priority */ | |
4257 | if (param->sched_priority > p->rt_priority && | |
4258 | param->sched_priority > rlim_rtprio) | |
4259 | return -EPERM; | |
4260 | } | |
dd41f596 IM |
4261 | /* |
4262 | * Like positive nice levels, dont allow tasks to | |
4263 | * move out of SCHED_IDLE either: | |
4264 | */ | |
4265 | if (p->policy == SCHED_IDLE && policy != SCHED_IDLE) | |
4266 | return -EPERM; | |
5fe1d75f | 4267 | |
37e4ab3f OC |
4268 | /* can't change other user's priorities */ |
4269 | if ((current->euid != p->euid) && | |
4270 | (current->euid != p->uid)) | |
4271 | return -EPERM; | |
4272 | } | |
1da177e4 LT |
4273 | |
4274 | retval = security_task_setscheduler(p, policy, param); | |
4275 | if (retval) | |
4276 | return retval; | |
b29739f9 IM |
4277 | /* |
4278 | * make sure no PI-waiters arrive (or leave) while we are | |
4279 | * changing the priority of the task: | |
4280 | */ | |
4281 | spin_lock_irqsave(&p->pi_lock, flags); | |
1da177e4 LT |
4282 | /* |
4283 | * To be able to change p->policy safely, the apropriate | |
4284 | * runqueue lock must be held. | |
4285 | */ | |
b29739f9 | 4286 | rq = __task_rq_lock(p); |
1da177e4 LT |
4287 | /* recheck policy now with rq lock held */ |
4288 | if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) { | |
4289 | policy = oldpolicy = -1; | |
b29739f9 IM |
4290 | __task_rq_unlock(rq); |
4291 | spin_unlock_irqrestore(&p->pi_lock, flags); | |
1da177e4 LT |
4292 | goto recheck; |
4293 | } | |
2daa3577 | 4294 | update_rq_clock(rq); |
dd41f596 | 4295 | on_rq = p->se.on_rq; |
051a1d1a | 4296 | running = task_current(rq, p); |
83b699ed | 4297 | if (on_rq) { |
2e1cb74a | 4298 | deactivate_task(rq, p, 0); |
83b699ed SV |
4299 | if (running) |
4300 | p->sched_class->put_prev_task(rq, p); | |
4301 | } | |
f6b53205 | 4302 | |
1da177e4 | 4303 | oldprio = p->prio; |
dd41f596 | 4304 | __setscheduler(rq, p, policy, param->sched_priority); |
f6b53205 | 4305 | |
dd41f596 | 4306 | if (on_rq) { |
83b699ed SV |
4307 | if (running) |
4308 | p->sched_class->set_curr_task(rq); | |
dd41f596 | 4309 | activate_task(rq, p, 0); |
1da177e4 LT |
4310 | /* |
4311 | * Reschedule if we are currently running on this runqueue and | |
d5f9f942 AM |
4312 | * our priority decreased, or if we are not currently running on |
4313 | * this runqueue and our priority is higher than the current's | |
1da177e4 | 4314 | */ |
83b699ed | 4315 | if (running) { |
d5f9f942 AM |
4316 | if (p->prio > oldprio) |
4317 | resched_task(rq->curr); | |
dd41f596 IM |
4318 | } else { |
4319 | check_preempt_curr(rq, p); | |
4320 | } | |
1da177e4 | 4321 | } |
b29739f9 IM |
4322 | __task_rq_unlock(rq); |
4323 | spin_unlock_irqrestore(&p->pi_lock, flags); | |
4324 | ||
95e02ca9 TG |
4325 | rt_mutex_adjust_pi(p); |
4326 | ||
1da177e4 LT |
4327 | return 0; |
4328 | } | |
4329 | EXPORT_SYMBOL_GPL(sched_setscheduler); | |
4330 | ||
95cdf3b7 IM |
4331 | static int |
4332 | do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param) | |
1da177e4 | 4333 | { |
1da177e4 LT |
4334 | struct sched_param lparam; |
4335 | struct task_struct *p; | |
36c8b586 | 4336 | int retval; |
1da177e4 LT |
4337 | |
4338 | if (!param || pid < 0) | |
4339 | return -EINVAL; | |
4340 | if (copy_from_user(&lparam, param, sizeof(struct sched_param))) | |
4341 | return -EFAULT; | |
5fe1d75f ON |
4342 | |
4343 | rcu_read_lock(); | |
4344 | retval = -ESRCH; | |
1da177e4 | 4345 | p = find_process_by_pid(pid); |
5fe1d75f ON |
4346 | if (p != NULL) |
4347 | retval = sched_setscheduler(p, policy, &lparam); | |
4348 | rcu_read_unlock(); | |
36c8b586 | 4349 | |
1da177e4 LT |
4350 | return retval; |
4351 | } | |
4352 | ||
4353 | /** | |
4354 | * sys_sched_setscheduler - set/change the scheduler policy and RT priority | |
4355 | * @pid: the pid in question. | |
4356 | * @policy: new policy. | |
4357 | * @param: structure containing the new RT priority. | |
4358 | */ | |
41a2d6cf IM |
4359 | asmlinkage long |
4360 | sys_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param) | |
1da177e4 | 4361 | { |
c21761f1 JB |
4362 | /* negative values for policy are not valid */ |
4363 | if (policy < 0) | |
4364 | return -EINVAL; | |
4365 | ||
1da177e4 LT |
4366 | return do_sched_setscheduler(pid, policy, param); |
4367 | } | |
4368 | ||
4369 | /** | |
4370 | * sys_sched_setparam - set/change the RT priority of a thread | |
4371 | * @pid: the pid in question. | |
4372 | * @param: structure containing the new RT priority. | |
4373 | */ | |
4374 | asmlinkage long sys_sched_setparam(pid_t pid, struct sched_param __user *param) | |
4375 | { | |
4376 | return do_sched_setscheduler(pid, -1, param); | |
4377 | } | |
4378 | ||
4379 | /** | |
4380 | * sys_sched_getscheduler - get the policy (scheduling class) of a thread | |
4381 | * @pid: the pid in question. | |
4382 | */ | |
4383 | asmlinkage long sys_sched_getscheduler(pid_t pid) | |
4384 | { | |
36c8b586 | 4385 | struct task_struct *p; |
3a5c359a | 4386 | int retval; |
1da177e4 LT |
4387 | |
4388 | if (pid < 0) | |
3a5c359a | 4389 | return -EINVAL; |
1da177e4 LT |
4390 | |
4391 | retval = -ESRCH; | |
4392 | read_lock(&tasklist_lock); | |
4393 | p = find_process_by_pid(pid); | |
4394 | if (p) { | |
4395 | retval = security_task_getscheduler(p); | |
4396 | if (!retval) | |
4397 | retval = p->policy; | |
4398 | } | |
4399 | read_unlock(&tasklist_lock); | |
1da177e4 LT |
4400 | return retval; |
4401 | } | |
4402 | ||
4403 | /** | |
4404 | * sys_sched_getscheduler - get the RT priority of a thread | |
4405 | * @pid: the pid in question. | |
4406 | * @param: structure containing the RT priority. | |
4407 | */ | |
4408 | asmlinkage long sys_sched_getparam(pid_t pid, struct sched_param __user *param) | |
4409 | { | |
4410 | struct sched_param lp; | |
36c8b586 | 4411 | struct task_struct *p; |
3a5c359a | 4412 | int retval; |
1da177e4 LT |
4413 | |
4414 | if (!param || pid < 0) | |
3a5c359a | 4415 | return -EINVAL; |
1da177e4 LT |
4416 | |
4417 | read_lock(&tasklist_lock); | |
4418 | p = find_process_by_pid(pid); | |
4419 | retval = -ESRCH; | |
4420 | if (!p) | |
4421 | goto out_unlock; | |
4422 | ||
4423 | retval = security_task_getscheduler(p); | |
4424 | if (retval) | |
4425 | goto out_unlock; | |
4426 | ||
4427 | lp.sched_priority = p->rt_priority; | |
4428 | read_unlock(&tasklist_lock); | |
4429 | ||
4430 | /* | |
4431 | * This one might sleep, we cannot do it with a spinlock held ... | |
4432 | */ | |
4433 | retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0; | |
4434 | ||
1da177e4 LT |
4435 | return retval; |
4436 | ||
4437 | out_unlock: | |
4438 | read_unlock(&tasklist_lock); | |
4439 | return retval; | |
4440 | } | |
4441 | ||
4442 | long sched_setaffinity(pid_t pid, cpumask_t new_mask) | |
4443 | { | |
1da177e4 | 4444 | cpumask_t cpus_allowed; |
36c8b586 IM |
4445 | struct task_struct *p; |
4446 | int retval; | |
1da177e4 | 4447 | |
95402b38 | 4448 | get_online_cpus(); |
1da177e4 LT |
4449 | read_lock(&tasklist_lock); |
4450 | ||
4451 | p = find_process_by_pid(pid); | |
4452 | if (!p) { | |
4453 | read_unlock(&tasklist_lock); | |
95402b38 | 4454 | put_online_cpus(); |
1da177e4 LT |
4455 | return -ESRCH; |
4456 | } | |
4457 | ||
4458 | /* | |
4459 | * It is not safe to call set_cpus_allowed with the | |
41a2d6cf | 4460 | * tasklist_lock held. We will bump the task_struct's |
1da177e4 LT |
4461 | * usage count and then drop tasklist_lock. |
4462 | */ | |
4463 | get_task_struct(p); | |
4464 | read_unlock(&tasklist_lock); | |
4465 | ||
4466 | retval = -EPERM; | |
4467 | if ((current->euid != p->euid) && (current->euid != p->uid) && | |
4468 | !capable(CAP_SYS_NICE)) | |
4469 | goto out_unlock; | |
4470 | ||
e7834f8f DQ |
4471 | retval = security_task_setscheduler(p, 0, NULL); |
4472 | if (retval) | |
4473 | goto out_unlock; | |
4474 | ||
1da177e4 LT |
4475 | cpus_allowed = cpuset_cpus_allowed(p); |
4476 | cpus_and(new_mask, new_mask, cpus_allowed); | |
8707d8b8 | 4477 | again: |
1da177e4 LT |
4478 | retval = set_cpus_allowed(p, new_mask); |
4479 | ||
8707d8b8 PM |
4480 | if (!retval) { |
4481 | cpus_allowed = cpuset_cpus_allowed(p); | |
4482 | if (!cpus_subset(new_mask, cpus_allowed)) { | |
4483 | /* | |
4484 | * We must have raced with a concurrent cpuset | |
4485 | * update. Just reset the cpus_allowed to the | |
4486 | * cpuset's cpus_allowed | |
4487 | */ | |
4488 | new_mask = cpus_allowed; | |
4489 | goto again; | |
4490 | } | |
4491 | } | |
1da177e4 LT |
4492 | out_unlock: |
4493 | put_task_struct(p); | |
95402b38 | 4494 | put_online_cpus(); |
1da177e4 LT |
4495 | return retval; |
4496 | } | |
4497 | ||
4498 | static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len, | |
4499 | cpumask_t *new_mask) | |
4500 | { | |
4501 | if (len < sizeof(cpumask_t)) { | |
4502 | memset(new_mask, 0, sizeof(cpumask_t)); | |
4503 | } else if (len > sizeof(cpumask_t)) { | |
4504 | len = sizeof(cpumask_t); | |
4505 | } | |
4506 | return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0; | |
4507 | } | |
4508 | ||
4509 | /** | |
4510 | * sys_sched_setaffinity - set the cpu affinity of a process | |
4511 | * @pid: pid of the process | |
4512 | * @len: length in bytes of the bitmask pointed to by user_mask_ptr | |
4513 | * @user_mask_ptr: user-space pointer to the new cpu mask | |
4514 | */ | |
4515 | asmlinkage long sys_sched_setaffinity(pid_t pid, unsigned int len, | |
4516 | unsigned long __user *user_mask_ptr) | |
4517 | { | |
4518 | cpumask_t new_mask; | |
4519 | int retval; | |
4520 | ||
4521 | retval = get_user_cpu_mask(user_mask_ptr, len, &new_mask); | |
4522 | if (retval) | |
4523 | return retval; | |
4524 | ||
4525 | return sched_setaffinity(pid, new_mask); | |
4526 | } | |
4527 | ||
4528 | /* | |
4529 | * Represents all cpu's present in the system | |
4530 | * In systems capable of hotplug, this map could dynamically grow | |
4531 | * as new cpu's are detected in the system via any platform specific | |
4532 | * method, such as ACPI for e.g. | |
4533 | */ | |
4534 | ||
4cef0c61 | 4535 | cpumask_t cpu_present_map __read_mostly; |
1da177e4 LT |
4536 | EXPORT_SYMBOL(cpu_present_map); |
4537 | ||
4538 | #ifndef CONFIG_SMP | |
4cef0c61 | 4539 | cpumask_t cpu_online_map __read_mostly = CPU_MASK_ALL; |
e16b38f7 GB |
4540 | EXPORT_SYMBOL(cpu_online_map); |
4541 | ||
4cef0c61 | 4542 | cpumask_t cpu_possible_map __read_mostly = CPU_MASK_ALL; |
e16b38f7 | 4543 | EXPORT_SYMBOL(cpu_possible_map); |
1da177e4 LT |
4544 | #endif |
4545 | ||
4546 | long sched_getaffinity(pid_t pid, cpumask_t *mask) | |
4547 | { | |
36c8b586 | 4548 | struct task_struct *p; |
1da177e4 | 4549 | int retval; |
1da177e4 | 4550 | |
95402b38 | 4551 | get_online_cpus(); |
1da177e4 LT |
4552 | read_lock(&tasklist_lock); |
4553 | ||
4554 | retval = -ESRCH; | |
4555 | p = find_process_by_pid(pid); | |
4556 | if (!p) | |
4557 | goto out_unlock; | |
4558 | ||
e7834f8f DQ |
4559 | retval = security_task_getscheduler(p); |
4560 | if (retval) | |
4561 | goto out_unlock; | |
4562 | ||
2f7016d9 | 4563 | cpus_and(*mask, p->cpus_allowed, cpu_online_map); |
1da177e4 LT |
4564 | |
4565 | out_unlock: | |
4566 | read_unlock(&tasklist_lock); | |
95402b38 | 4567 | put_online_cpus(); |
1da177e4 | 4568 | |
9531b62f | 4569 | return retval; |
1da177e4 LT |
4570 | } |
4571 | ||
4572 | /** | |
4573 | * sys_sched_getaffinity - get the cpu affinity of a process | |
4574 | * @pid: pid of the process | |
4575 | * @len: length in bytes of the bitmask pointed to by user_mask_ptr | |
4576 | * @user_mask_ptr: user-space pointer to hold the current cpu mask | |
4577 | */ | |
4578 | asmlinkage long sys_sched_getaffinity(pid_t pid, unsigned int len, | |
4579 | unsigned long __user *user_mask_ptr) | |
4580 | { | |
4581 | int ret; | |
4582 | cpumask_t mask; | |
4583 | ||
4584 | if (len < sizeof(cpumask_t)) | |
4585 | return -EINVAL; | |
4586 | ||
4587 | ret = sched_getaffinity(pid, &mask); | |
4588 | if (ret < 0) | |
4589 | return ret; | |
4590 | ||
4591 | if (copy_to_user(user_mask_ptr, &mask, sizeof(cpumask_t))) | |
4592 | return -EFAULT; | |
4593 | ||
4594 | return sizeof(cpumask_t); | |
4595 | } | |
4596 | ||
4597 | /** | |
4598 | * sys_sched_yield - yield the current processor to other threads. | |
4599 | * | |
dd41f596 IM |
4600 | * This function yields the current CPU to other tasks. If there are no |
4601 | * other threads running on this CPU then this function will return. | |
1da177e4 LT |
4602 | */ |
4603 | asmlinkage long sys_sched_yield(void) | |
4604 | { | |
70b97a7f | 4605 | struct rq *rq = this_rq_lock(); |
1da177e4 | 4606 | |
2d72376b | 4607 | schedstat_inc(rq, yld_count); |
4530d7ab | 4608 | current->sched_class->yield_task(rq); |
1da177e4 LT |
4609 | |
4610 | /* | |
4611 | * Since we are going to call schedule() anyway, there's | |
4612 | * no need to preempt or enable interrupts: | |
4613 | */ | |
4614 | __release(rq->lock); | |
8a25d5de | 4615 | spin_release(&rq->lock.dep_map, 1, _THIS_IP_); |
1da177e4 LT |
4616 | _raw_spin_unlock(&rq->lock); |
4617 | preempt_enable_no_resched(); | |
4618 | ||
4619 | schedule(); | |
4620 | ||
4621 | return 0; | |
4622 | } | |
4623 | ||
e7b38404 | 4624 | static void __cond_resched(void) |
1da177e4 | 4625 | { |
8e0a43d8 IM |
4626 | #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP |
4627 | __might_sleep(__FILE__, __LINE__); | |
4628 | #endif | |
5bbcfd90 IM |
4629 | /* |
4630 | * The BKS might be reacquired before we have dropped | |
4631 | * PREEMPT_ACTIVE, which could trigger a second | |
4632 | * cond_resched() call. | |
4633 | */ | |
1da177e4 LT |
4634 | do { |
4635 | add_preempt_count(PREEMPT_ACTIVE); | |
4636 | schedule(); | |
4637 | sub_preempt_count(PREEMPT_ACTIVE); | |
4638 | } while (need_resched()); | |
4639 | } | |
4640 | ||
4641 | int __sched cond_resched(void) | |
4642 | { | |
9414232f IM |
4643 | if (need_resched() && !(preempt_count() & PREEMPT_ACTIVE) && |
4644 | system_state == SYSTEM_RUNNING) { | |
1da177e4 LT |
4645 | __cond_resched(); |
4646 | return 1; | |
4647 | } | |
4648 | return 0; | |
4649 | } | |
1da177e4 LT |
4650 | EXPORT_SYMBOL(cond_resched); |
4651 | ||
4652 | /* | |
4653 | * cond_resched_lock() - if a reschedule is pending, drop the given lock, | |
4654 | * call schedule, and on return reacquire the lock. | |
4655 | * | |
41a2d6cf | 4656 | * This works OK both with and without CONFIG_PREEMPT. We do strange low-level |
1da177e4 LT |
4657 | * operations here to prevent schedule() from being called twice (once via |
4658 | * spin_unlock(), once by hand). | |
4659 | */ | |
95cdf3b7 | 4660 | int cond_resched_lock(spinlock_t *lock) |
1da177e4 | 4661 | { |
6df3cecb JK |
4662 | int ret = 0; |
4663 | ||
1da177e4 LT |
4664 | if (need_lockbreak(lock)) { |
4665 | spin_unlock(lock); | |
4666 | cpu_relax(); | |
6df3cecb | 4667 | ret = 1; |
1da177e4 LT |
4668 | spin_lock(lock); |
4669 | } | |
9414232f | 4670 | if (need_resched() && system_state == SYSTEM_RUNNING) { |
8a25d5de | 4671 | spin_release(&lock->dep_map, 1, _THIS_IP_); |
1da177e4 LT |
4672 | _raw_spin_unlock(lock); |
4673 | preempt_enable_no_resched(); | |
4674 | __cond_resched(); | |
6df3cecb | 4675 | ret = 1; |
1da177e4 | 4676 | spin_lock(lock); |
1da177e4 | 4677 | } |
6df3cecb | 4678 | return ret; |
1da177e4 | 4679 | } |
1da177e4 LT |
4680 | EXPORT_SYMBOL(cond_resched_lock); |
4681 | ||
4682 | int __sched cond_resched_softirq(void) | |
4683 | { | |
4684 | BUG_ON(!in_softirq()); | |
4685 | ||
9414232f | 4686 | if (need_resched() && system_state == SYSTEM_RUNNING) { |
98d82567 | 4687 | local_bh_enable(); |
1da177e4 LT |
4688 | __cond_resched(); |
4689 | local_bh_disable(); | |
4690 | return 1; | |
4691 | } | |
4692 | return 0; | |
4693 | } | |
1da177e4 LT |
4694 | EXPORT_SYMBOL(cond_resched_softirq); |
4695 | ||
1da177e4 LT |
4696 | /** |
4697 | * yield - yield the current processor to other threads. | |
4698 | * | |
72fd4a35 | 4699 | * This is a shortcut for kernel-space yielding - it marks the |
1da177e4 LT |
4700 | * thread runnable and calls sys_sched_yield(). |
4701 | */ | |
4702 | void __sched yield(void) | |
4703 | { | |
4704 | set_current_state(TASK_RUNNING); | |
4705 | sys_sched_yield(); | |
4706 | } | |
1da177e4 LT |
4707 | EXPORT_SYMBOL(yield); |
4708 | ||
4709 | /* | |
41a2d6cf | 4710 | * This task is about to go to sleep on IO. Increment rq->nr_iowait so |
1da177e4 LT |
4711 | * that process accounting knows that this is a task in IO wait state. |
4712 | * | |
4713 | * But don't do that if it is a deliberate, throttling IO wait (this task | |
4714 | * has set its backing_dev_info: the queue against which it should throttle) | |
4715 | */ | |
4716 | void __sched io_schedule(void) | |
4717 | { | |
70b97a7f | 4718 | struct rq *rq = &__raw_get_cpu_var(runqueues); |
1da177e4 | 4719 | |
0ff92245 | 4720 | delayacct_blkio_start(); |
1da177e4 LT |
4721 | atomic_inc(&rq->nr_iowait); |
4722 | schedule(); | |
4723 | atomic_dec(&rq->nr_iowait); | |
0ff92245 | 4724 | delayacct_blkio_end(); |
1da177e4 | 4725 | } |
1da177e4 LT |
4726 | EXPORT_SYMBOL(io_schedule); |
4727 | ||
4728 | long __sched io_schedule_timeout(long timeout) | |
4729 | { | |
70b97a7f | 4730 | struct rq *rq = &__raw_get_cpu_var(runqueues); |
1da177e4 LT |
4731 | long ret; |
4732 | ||
0ff92245 | 4733 | delayacct_blkio_start(); |
1da177e4 LT |
4734 | atomic_inc(&rq->nr_iowait); |
4735 | ret = schedule_timeout(timeout); | |
4736 | atomic_dec(&rq->nr_iowait); | |
0ff92245 | 4737 | delayacct_blkio_end(); |
1da177e4 LT |
4738 | return ret; |
4739 | } | |
4740 | ||
4741 | /** | |
4742 | * sys_sched_get_priority_max - return maximum RT priority. | |
4743 | * @policy: scheduling class. | |
4744 | * | |
4745 | * this syscall returns the maximum rt_priority that can be used | |
4746 | * by a given scheduling class. | |
4747 | */ | |
4748 | asmlinkage long sys_sched_get_priority_max(int policy) | |
4749 | { | |
4750 | int ret = -EINVAL; | |
4751 | ||
4752 | switch (policy) { | |
4753 | case SCHED_FIFO: | |
4754 | case SCHED_RR: | |
4755 | ret = MAX_USER_RT_PRIO-1; | |
4756 | break; | |
4757 | case SCHED_NORMAL: | |
b0a9499c | 4758 | case SCHED_BATCH: |
dd41f596 | 4759 | case SCHED_IDLE: |
1da177e4 LT |
4760 | ret = 0; |
4761 | break; | |
4762 | } | |
4763 | return ret; | |
4764 | } | |
4765 | ||
4766 | /** | |
4767 | * sys_sched_get_priority_min - return minimum RT priority. | |
4768 | * @policy: scheduling class. | |
4769 | * | |
4770 | * this syscall returns the minimum rt_priority that can be used | |
4771 | * by a given scheduling class. | |
4772 | */ | |
4773 | asmlinkage long sys_sched_get_priority_min(int policy) | |
4774 | { | |
4775 | int ret = -EINVAL; | |
4776 | ||
4777 | switch (policy) { | |
4778 | case SCHED_FIFO: | |
4779 | case SCHED_RR: | |
4780 | ret = 1; | |
4781 | break; | |
4782 | case SCHED_NORMAL: | |
b0a9499c | 4783 | case SCHED_BATCH: |
dd41f596 | 4784 | case SCHED_IDLE: |
1da177e4 LT |
4785 | ret = 0; |
4786 | } | |
4787 | return ret; | |
4788 | } | |
4789 | ||
4790 | /** | |
4791 | * sys_sched_rr_get_interval - return the default timeslice of a process. | |
4792 | * @pid: pid of the process. | |
4793 | * @interval: userspace pointer to the timeslice value. | |
4794 | * | |
4795 | * this syscall writes the default timeslice value of a given process | |
4796 | * into the user-space timespec buffer. A value of '0' means infinity. | |
4797 | */ | |
4798 | asmlinkage | |
4799 | long sys_sched_rr_get_interval(pid_t pid, struct timespec __user *interval) | |
4800 | { | |
36c8b586 | 4801 | struct task_struct *p; |
a4ec24b4 | 4802 | unsigned int time_slice; |
3a5c359a | 4803 | int retval; |
1da177e4 | 4804 | struct timespec t; |
1da177e4 LT |
4805 | |
4806 | if (pid < 0) | |
3a5c359a | 4807 | return -EINVAL; |
1da177e4 LT |
4808 | |
4809 | retval = -ESRCH; | |
4810 | read_lock(&tasklist_lock); | |
4811 | p = find_process_by_pid(pid); | |
4812 | if (!p) | |
4813 | goto out_unlock; | |
4814 | ||
4815 | retval = security_task_getscheduler(p); | |
4816 | if (retval) | |
4817 | goto out_unlock; | |
4818 | ||
77034937 IM |
4819 | /* |
4820 | * Time slice is 0 for SCHED_FIFO tasks and for SCHED_OTHER | |
4821 | * tasks that are on an otherwise idle runqueue: | |
4822 | */ | |
4823 | time_slice = 0; | |
4824 | if (p->policy == SCHED_RR) { | |
a4ec24b4 | 4825 | time_slice = DEF_TIMESLICE; |
77034937 | 4826 | } else { |
a4ec24b4 DA |
4827 | struct sched_entity *se = &p->se; |
4828 | unsigned long flags; | |
4829 | struct rq *rq; | |
4830 | ||
4831 | rq = task_rq_lock(p, &flags); | |
77034937 IM |
4832 | if (rq->cfs.load.weight) |
4833 | time_slice = NS_TO_JIFFIES(sched_slice(&rq->cfs, se)); | |
a4ec24b4 DA |
4834 | task_rq_unlock(rq, &flags); |
4835 | } | |
1da177e4 | 4836 | read_unlock(&tasklist_lock); |
a4ec24b4 | 4837 | jiffies_to_timespec(time_slice, &t); |
1da177e4 | 4838 | retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0; |
1da177e4 | 4839 | return retval; |
3a5c359a | 4840 | |
1da177e4 LT |
4841 | out_unlock: |
4842 | read_unlock(&tasklist_lock); | |
4843 | return retval; | |
4844 | } | |
4845 | ||
2ed6e34f | 4846 | static const char stat_nam[] = "RSDTtZX"; |
36c8b586 | 4847 | |
82a1fcb9 | 4848 | void sched_show_task(struct task_struct *p) |
1da177e4 | 4849 | { |
1da177e4 | 4850 | unsigned long free = 0; |
36c8b586 | 4851 | unsigned state; |
1da177e4 | 4852 | |
1da177e4 | 4853 | state = p->state ? __ffs(p->state) + 1 : 0; |
cc4ea795 | 4854 | printk(KERN_INFO "%-13.13s %c", p->comm, |
2ed6e34f | 4855 | state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?'); |
4bd77321 | 4856 | #if BITS_PER_LONG == 32 |
1da177e4 | 4857 | if (state == TASK_RUNNING) |
cc4ea795 | 4858 | printk(KERN_CONT " running "); |
1da177e4 | 4859 | else |
cc4ea795 | 4860 | printk(KERN_CONT " %08lx ", thread_saved_pc(p)); |
1da177e4 LT |
4861 | #else |
4862 | if (state == TASK_RUNNING) | |
cc4ea795 | 4863 | printk(KERN_CONT " running task "); |
1da177e4 | 4864 | else |
cc4ea795 | 4865 | printk(KERN_CONT " %016lx ", thread_saved_pc(p)); |
1da177e4 LT |
4866 | #endif |
4867 | #ifdef CONFIG_DEBUG_STACK_USAGE | |
4868 | { | |
10ebffde | 4869 | unsigned long *n = end_of_stack(p); |
1da177e4 LT |
4870 | while (!*n) |
4871 | n++; | |
10ebffde | 4872 | free = (unsigned long)n - (unsigned long)end_of_stack(p); |
1da177e4 LT |
4873 | } |
4874 | #endif | |
ba25f9dc | 4875 | printk(KERN_CONT "%5lu %5d %6d\n", free, |
fcfd50af | 4876 | task_pid_nr(p), task_pid_nr(p->real_parent)); |
1da177e4 LT |
4877 | |
4878 | if (state != TASK_RUNNING) | |
4879 | show_stack(p, NULL); | |
4880 | } | |
4881 | ||
e59e2ae2 | 4882 | void show_state_filter(unsigned long state_filter) |
1da177e4 | 4883 | { |
36c8b586 | 4884 | struct task_struct *g, *p; |
1da177e4 | 4885 | |
4bd77321 IM |
4886 | #if BITS_PER_LONG == 32 |
4887 | printk(KERN_INFO | |
4888 | " task PC stack pid father\n"); | |
1da177e4 | 4889 | #else |
4bd77321 IM |
4890 | printk(KERN_INFO |
4891 | " task PC stack pid father\n"); | |
1da177e4 LT |
4892 | #endif |
4893 | read_lock(&tasklist_lock); | |
4894 | do_each_thread(g, p) { | |
4895 | /* | |
4896 | * reset the NMI-timeout, listing all files on a slow | |
4897 | * console might take alot of time: | |
4898 | */ | |
4899 | touch_nmi_watchdog(); | |
39bc89fd | 4900 | if (!state_filter || (p->state & state_filter)) |
82a1fcb9 | 4901 | sched_show_task(p); |
1da177e4 LT |
4902 | } while_each_thread(g, p); |
4903 | ||
04c9167f JF |
4904 | touch_all_softlockup_watchdogs(); |
4905 | ||
dd41f596 IM |
4906 | #ifdef CONFIG_SCHED_DEBUG |
4907 | sysrq_sched_debug_show(); | |
4908 | #endif | |
1da177e4 | 4909 | read_unlock(&tasklist_lock); |
e59e2ae2 IM |
4910 | /* |
4911 | * Only show locks if all tasks are dumped: | |
4912 | */ | |
4913 | if (state_filter == -1) | |
4914 | debug_show_all_locks(); | |
1da177e4 LT |
4915 | } |
4916 | ||
1df21055 IM |
4917 | void __cpuinit init_idle_bootup_task(struct task_struct *idle) |
4918 | { | |
dd41f596 | 4919 | idle->sched_class = &idle_sched_class; |
1df21055 IM |
4920 | } |
4921 | ||
f340c0d1 IM |
4922 | /** |
4923 | * init_idle - set up an idle thread for a given CPU | |
4924 | * @idle: task in question | |
4925 | * @cpu: cpu the idle task belongs to | |
4926 | * | |
4927 | * NOTE: this function does not set the idle thread's NEED_RESCHED | |
4928 | * flag, to make booting more robust. | |
4929 | */ | |
5c1e1767 | 4930 | void __cpuinit init_idle(struct task_struct *idle, int cpu) |
1da177e4 | 4931 | { |
70b97a7f | 4932 | struct rq *rq = cpu_rq(cpu); |
1da177e4 LT |
4933 | unsigned long flags; |
4934 | ||
dd41f596 IM |
4935 | __sched_fork(idle); |
4936 | idle->se.exec_start = sched_clock(); | |
4937 | ||
b29739f9 | 4938 | idle->prio = idle->normal_prio = MAX_PRIO; |
1da177e4 | 4939 | idle->cpus_allowed = cpumask_of_cpu(cpu); |
dd41f596 | 4940 | __set_task_cpu(idle, cpu); |
1da177e4 LT |
4941 | |
4942 | spin_lock_irqsave(&rq->lock, flags); | |
4943 | rq->curr = rq->idle = idle; | |
4866cde0 NP |
4944 | #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW) |
4945 | idle->oncpu = 1; | |
4946 | #endif | |
1da177e4 LT |
4947 | spin_unlock_irqrestore(&rq->lock, flags); |
4948 | ||
4949 | /* Set the preempt count _outside_ the spinlocks! */ | |
4950 | #if defined(CONFIG_PREEMPT) && !defined(CONFIG_PREEMPT_BKL) | |
a1261f54 | 4951 | task_thread_info(idle)->preempt_count = (idle->lock_depth >= 0); |
1da177e4 | 4952 | #else |
a1261f54 | 4953 | task_thread_info(idle)->preempt_count = 0; |
1da177e4 | 4954 | #endif |
dd41f596 IM |
4955 | /* |
4956 | * The idle tasks have their own, simple scheduling class: | |
4957 | */ | |
4958 | idle->sched_class = &idle_sched_class; | |
1da177e4 LT |
4959 | } |
4960 | ||
4961 | /* | |
4962 | * In a system that switches off the HZ timer nohz_cpu_mask | |
4963 | * indicates which cpus entered this state. This is used | |
4964 | * in the rcu update to wait only for active cpus. For system | |
4965 | * which do not switch off the HZ timer nohz_cpu_mask should | |
4966 | * always be CPU_MASK_NONE. | |
4967 | */ | |
4968 | cpumask_t nohz_cpu_mask = CPU_MASK_NONE; | |
4969 | ||
19978ca6 IM |
4970 | /* |
4971 | * Increase the granularity value when there are more CPUs, | |
4972 | * because with more CPUs the 'effective latency' as visible | |
4973 | * to users decreases. But the relationship is not linear, | |
4974 | * so pick a second-best guess by going with the log2 of the | |
4975 | * number of CPUs. | |
4976 | * | |
4977 | * This idea comes from the SD scheduler of Con Kolivas: | |
4978 | */ | |
4979 | static inline void sched_init_granularity(void) | |
4980 | { | |
4981 | unsigned int factor = 1 + ilog2(num_online_cpus()); | |
4982 | const unsigned long limit = 200000000; | |
4983 | ||
4984 | sysctl_sched_min_granularity *= factor; | |
4985 | if (sysctl_sched_min_granularity > limit) | |
4986 | sysctl_sched_min_granularity = limit; | |
4987 | ||
4988 | sysctl_sched_latency *= factor; | |
4989 | if (sysctl_sched_latency > limit) | |
4990 | sysctl_sched_latency = limit; | |
4991 | ||
4992 | sysctl_sched_wakeup_granularity *= factor; | |
4993 | sysctl_sched_batch_wakeup_granularity *= factor; | |
4994 | } | |
4995 | ||
1da177e4 LT |
4996 | #ifdef CONFIG_SMP |
4997 | /* | |
4998 | * This is how migration works: | |
4999 | * | |
70b97a7f | 5000 | * 1) we queue a struct migration_req structure in the source CPU's |
1da177e4 LT |
5001 | * runqueue and wake up that CPU's migration thread. |
5002 | * 2) we down() the locked semaphore => thread blocks. | |
5003 | * 3) migration thread wakes up (implicitly it forces the migrated | |
5004 | * thread off the CPU) | |
5005 | * 4) it gets the migration request and checks whether the migrated | |
5006 | * task is still in the wrong runqueue. | |
5007 | * 5) if it's in the wrong runqueue then the migration thread removes | |
5008 | * it and puts it into the right queue. | |
5009 | * 6) migration thread up()s the semaphore. | |
5010 | * 7) we wake up and the migration is done. | |
5011 | */ | |
5012 | ||
5013 | /* | |
5014 | * Change a given task's CPU affinity. Migrate the thread to a | |
5015 | * proper CPU and schedule it away if the CPU it's executing on | |
5016 | * is removed from the allowed bitmask. | |
5017 | * | |
5018 | * NOTE: the caller must have a valid reference to the task, the | |
41a2d6cf | 5019 | * task must not exit() & deallocate itself prematurely. The |
1da177e4 LT |
5020 | * call is not atomic; no spinlocks may be held. |
5021 | */ | |
36c8b586 | 5022 | int set_cpus_allowed(struct task_struct *p, cpumask_t new_mask) |
1da177e4 | 5023 | { |
70b97a7f | 5024 | struct migration_req req; |
1da177e4 | 5025 | unsigned long flags; |
70b97a7f | 5026 | struct rq *rq; |
48f24c4d | 5027 | int ret = 0; |
1da177e4 LT |
5028 | |
5029 | rq = task_rq_lock(p, &flags); | |
5030 | if (!cpus_intersects(new_mask, cpu_online_map)) { | |
5031 | ret = -EINVAL; | |
5032 | goto out; | |
5033 | } | |
5034 | ||
73fe6aae GH |
5035 | if (p->sched_class->set_cpus_allowed) |
5036 | p->sched_class->set_cpus_allowed(p, &new_mask); | |
5037 | else { | |
5038 | p->cpus_allowed = new_mask; | |
5039 | p->nr_cpus_allowed = cpus_weight(new_mask); | |
5040 | } | |
5041 | ||
1da177e4 LT |
5042 | /* Can the task run on the task's current CPU? If so, we're done */ |
5043 | if (cpu_isset(task_cpu(p), new_mask)) | |
5044 | goto out; | |
5045 | ||
5046 | if (migrate_task(p, any_online_cpu(new_mask), &req)) { | |
5047 | /* Need help from migration thread: drop lock and wait. */ | |
5048 | task_rq_unlock(rq, &flags); | |
5049 | wake_up_process(rq->migration_thread); | |
5050 | wait_for_completion(&req.done); | |
5051 | tlb_migrate_finish(p->mm); | |
5052 | return 0; | |
5053 | } | |
5054 | out: | |
5055 | task_rq_unlock(rq, &flags); | |
48f24c4d | 5056 | |
1da177e4 LT |
5057 | return ret; |
5058 | } | |
1da177e4 LT |
5059 | EXPORT_SYMBOL_GPL(set_cpus_allowed); |
5060 | ||
5061 | /* | |
41a2d6cf | 5062 | * Move (not current) task off this cpu, onto dest cpu. We're doing |
1da177e4 LT |
5063 | * this because either it can't run here any more (set_cpus_allowed() |
5064 | * away from this CPU, or CPU going down), or because we're | |
5065 | * attempting to rebalance this task on exec (sched_exec). | |
5066 | * | |
5067 | * So we race with normal scheduler movements, but that's OK, as long | |
5068 | * as the task is no longer on this CPU. | |
efc30814 KK |
5069 | * |
5070 | * Returns non-zero if task was successfully migrated. | |
1da177e4 | 5071 | */ |
efc30814 | 5072 | static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu) |
1da177e4 | 5073 | { |
70b97a7f | 5074 | struct rq *rq_dest, *rq_src; |
dd41f596 | 5075 | int ret = 0, on_rq; |
1da177e4 LT |
5076 | |
5077 | if (unlikely(cpu_is_offline(dest_cpu))) | |
efc30814 | 5078 | return ret; |
1da177e4 LT |
5079 | |
5080 | rq_src = cpu_rq(src_cpu); | |
5081 | rq_dest = cpu_rq(dest_cpu); | |
5082 | ||
5083 | double_rq_lock(rq_src, rq_dest); | |
5084 | /* Already moved. */ | |
5085 | if (task_cpu(p) != src_cpu) | |
5086 | goto out; | |
5087 | /* Affinity changed (again). */ | |
5088 | if (!cpu_isset(dest_cpu, p->cpus_allowed)) | |
5089 | goto out; | |
5090 | ||
dd41f596 | 5091 | on_rq = p->se.on_rq; |
6e82a3be | 5092 | if (on_rq) |
2e1cb74a | 5093 | deactivate_task(rq_src, p, 0); |
6e82a3be | 5094 | |
1da177e4 | 5095 | set_task_cpu(p, dest_cpu); |
dd41f596 IM |
5096 | if (on_rq) { |
5097 | activate_task(rq_dest, p, 0); | |
5098 | check_preempt_curr(rq_dest, p); | |
1da177e4 | 5099 | } |
efc30814 | 5100 | ret = 1; |
1da177e4 LT |
5101 | out: |
5102 | double_rq_unlock(rq_src, rq_dest); | |
efc30814 | 5103 | return ret; |
1da177e4 LT |
5104 | } |
5105 | ||
5106 | /* | |
5107 | * migration_thread - this is a highprio system thread that performs | |
5108 | * thread migration by bumping thread off CPU then 'pushing' onto | |
5109 | * another runqueue. | |
5110 | */ | |
95cdf3b7 | 5111 | static int migration_thread(void *data) |
1da177e4 | 5112 | { |
1da177e4 | 5113 | int cpu = (long)data; |
70b97a7f | 5114 | struct rq *rq; |
1da177e4 LT |
5115 | |
5116 | rq = cpu_rq(cpu); | |
5117 | BUG_ON(rq->migration_thread != current); | |
5118 | ||
5119 | set_current_state(TASK_INTERRUPTIBLE); | |
5120 | while (!kthread_should_stop()) { | |
70b97a7f | 5121 | struct migration_req *req; |
1da177e4 | 5122 | struct list_head *head; |
1da177e4 | 5123 | |
1da177e4 LT |
5124 | spin_lock_irq(&rq->lock); |
5125 | ||
5126 | if (cpu_is_offline(cpu)) { | |
5127 | spin_unlock_irq(&rq->lock); | |
5128 | goto wait_to_die; | |
5129 | } | |
5130 | ||
5131 | if (rq->active_balance) { | |
5132 | active_load_balance(rq, cpu); | |
5133 | rq->active_balance = 0; | |
5134 | } | |
5135 | ||
5136 | head = &rq->migration_queue; | |
5137 | ||
5138 | if (list_empty(head)) { | |
5139 | spin_unlock_irq(&rq->lock); | |
5140 | schedule(); | |
5141 | set_current_state(TASK_INTERRUPTIBLE); | |
5142 | continue; | |
5143 | } | |
70b97a7f | 5144 | req = list_entry(head->next, struct migration_req, list); |
1da177e4 LT |
5145 | list_del_init(head->next); |
5146 | ||
674311d5 NP |
5147 | spin_unlock(&rq->lock); |
5148 | __migrate_task(req->task, cpu, req->dest_cpu); | |
5149 | local_irq_enable(); | |
1da177e4 LT |
5150 | |
5151 | complete(&req->done); | |
5152 | } | |
5153 | __set_current_state(TASK_RUNNING); | |
5154 | return 0; | |
5155 | ||
5156 | wait_to_die: | |
5157 | /* Wait for kthread_stop */ | |
5158 | set_current_state(TASK_INTERRUPTIBLE); | |
5159 | while (!kthread_should_stop()) { | |
5160 | schedule(); | |
5161 | set_current_state(TASK_INTERRUPTIBLE); | |
5162 | } | |
5163 | __set_current_state(TASK_RUNNING); | |
5164 | return 0; | |
5165 | } | |
5166 | ||
5167 | #ifdef CONFIG_HOTPLUG_CPU | |
f7b4cddc ON |
5168 | |
5169 | static int __migrate_task_irq(struct task_struct *p, int src_cpu, int dest_cpu) | |
5170 | { | |
5171 | int ret; | |
5172 | ||
5173 | local_irq_disable(); | |
5174 | ret = __migrate_task(p, src_cpu, dest_cpu); | |
5175 | local_irq_enable(); | |
5176 | return ret; | |
5177 | } | |
5178 | ||
054b9108 | 5179 | /* |
3a4fa0a2 | 5180 | * Figure out where task on dead CPU should go, use force if necessary. |
054b9108 KK |
5181 | * NOTE: interrupts should be disabled by the caller |
5182 | */ | |
48f24c4d | 5183 | static void move_task_off_dead_cpu(int dead_cpu, struct task_struct *p) |
1da177e4 | 5184 | { |
efc30814 | 5185 | unsigned long flags; |
1da177e4 | 5186 | cpumask_t mask; |
70b97a7f IM |
5187 | struct rq *rq; |
5188 | int dest_cpu; | |
1da177e4 | 5189 | |
3a5c359a AK |
5190 | do { |
5191 | /* On same node? */ | |
5192 | mask = node_to_cpumask(cpu_to_node(dead_cpu)); | |
5193 | cpus_and(mask, mask, p->cpus_allowed); | |
5194 | dest_cpu = any_online_cpu(mask); | |
5195 | ||
5196 | /* On any allowed CPU? */ | |
5197 | if (dest_cpu == NR_CPUS) | |
5198 | dest_cpu = any_online_cpu(p->cpus_allowed); | |
5199 | ||
5200 | /* No more Mr. Nice Guy. */ | |
5201 | if (dest_cpu == NR_CPUS) { | |
470fd646 CW |
5202 | cpumask_t cpus_allowed = cpuset_cpus_allowed_locked(p); |
5203 | /* | |
5204 | * Try to stay on the same cpuset, where the | |
5205 | * current cpuset may be a subset of all cpus. | |
5206 | * The cpuset_cpus_allowed_locked() variant of | |
41a2d6cf | 5207 | * cpuset_cpus_allowed() will not block. It must be |
470fd646 CW |
5208 | * called within calls to cpuset_lock/cpuset_unlock. |
5209 | */ | |
3a5c359a | 5210 | rq = task_rq_lock(p, &flags); |
470fd646 | 5211 | p->cpus_allowed = cpus_allowed; |
3a5c359a AK |
5212 | dest_cpu = any_online_cpu(p->cpus_allowed); |
5213 | task_rq_unlock(rq, &flags); | |
1da177e4 | 5214 | |
3a5c359a AK |
5215 | /* |
5216 | * Don't tell them about moving exiting tasks or | |
5217 | * kernel threads (both mm NULL), since they never | |
5218 | * leave kernel. | |
5219 | */ | |
41a2d6cf | 5220 | if (p->mm && printk_ratelimit()) { |
3a5c359a AK |
5221 | printk(KERN_INFO "process %d (%s) no " |
5222 | "longer affine to cpu%d\n", | |
41a2d6cf IM |
5223 | task_pid_nr(p), p->comm, dead_cpu); |
5224 | } | |
3a5c359a | 5225 | } |
f7b4cddc | 5226 | } while (!__migrate_task_irq(p, dead_cpu, dest_cpu)); |
1da177e4 LT |
5227 | } |
5228 | ||
5229 | /* | |
5230 | * While a dead CPU has no uninterruptible tasks queued at this point, | |
5231 | * it might still have a nonzero ->nr_uninterruptible counter, because | |
5232 | * for performance reasons the counter is not stricly tracking tasks to | |
5233 | * their home CPUs. So we just add the counter to another CPU's counter, | |
5234 | * to keep the global sum constant after CPU-down: | |
5235 | */ | |
70b97a7f | 5236 | static void migrate_nr_uninterruptible(struct rq *rq_src) |
1da177e4 | 5237 | { |
70b97a7f | 5238 | struct rq *rq_dest = cpu_rq(any_online_cpu(CPU_MASK_ALL)); |
1da177e4 LT |
5239 | unsigned long flags; |
5240 | ||
5241 | local_irq_save(flags); | |
5242 | double_rq_lock(rq_src, rq_dest); | |
5243 | rq_dest->nr_uninterruptible += rq_src->nr_uninterruptible; | |
5244 | rq_src->nr_uninterruptible = 0; | |
5245 | double_rq_unlock(rq_src, rq_dest); | |
5246 | local_irq_restore(flags); | |
5247 | } | |
5248 | ||
5249 | /* Run through task list and migrate tasks from the dead cpu. */ | |
5250 | static void migrate_live_tasks(int src_cpu) | |
5251 | { | |
48f24c4d | 5252 | struct task_struct *p, *t; |
1da177e4 | 5253 | |
f7b4cddc | 5254 | read_lock(&tasklist_lock); |
1da177e4 | 5255 | |
48f24c4d IM |
5256 | do_each_thread(t, p) { |
5257 | if (p == current) | |
1da177e4 LT |
5258 | continue; |
5259 | ||
48f24c4d IM |
5260 | if (task_cpu(p) == src_cpu) |
5261 | move_task_off_dead_cpu(src_cpu, p); | |
5262 | } while_each_thread(t, p); | |
1da177e4 | 5263 | |
f7b4cddc | 5264 | read_unlock(&tasklist_lock); |
1da177e4 LT |
5265 | } |
5266 | ||
dd41f596 IM |
5267 | /* |
5268 | * Schedules idle task to be the next runnable task on current CPU. | |
94bc9a7b DA |
5269 | * It does so by boosting its priority to highest possible. |
5270 | * Used by CPU offline code. | |
1da177e4 LT |
5271 | */ |
5272 | void sched_idle_next(void) | |
5273 | { | |
48f24c4d | 5274 | int this_cpu = smp_processor_id(); |
70b97a7f | 5275 | struct rq *rq = cpu_rq(this_cpu); |
1da177e4 LT |
5276 | struct task_struct *p = rq->idle; |
5277 | unsigned long flags; | |
5278 | ||
5279 | /* cpu has to be offline */ | |
48f24c4d | 5280 | BUG_ON(cpu_online(this_cpu)); |
1da177e4 | 5281 | |
48f24c4d IM |
5282 | /* |
5283 | * Strictly not necessary since rest of the CPUs are stopped by now | |
5284 | * and interrupts disabled on the current cpu. | |
1da177e4 LT |
5285 | */ |
5286 | spin_lock_irqsave(&rq->lock, flags); | |
5287 | ||
dd41f596 | 5288 | __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1); |
48f24c4d | 5289 | |
94bc9a7b DA |
5290 | update_rq_clock(rq); |
5291 | activate_task(rq, p, 0); | |
1da177e4 LT |
5292 | |
5293 | spin_unlock_irqrestore(&rq->lock, flags); | |
5294 | } | |
5295 | ||
48f24c4d IM |
5296 | /* |
5297 | * Ensures that the idle task is using init_mm right before its cpu goes | |
1da177e4 LT |
5298 | * offline. |
5299 | */ | |
5300 | void idle_task_exit(void) | |
5301 | { | |
5302 | struct mm_struct *mm = current->active_mm; | |
5303 | ||
5304 | BUG_ON(cpu_online(smp_processor_id())); | |
5305 | ||
5306 | if (mm != &init_mm) | |
5307 | switch_mm(mm, &init_mm, current); | |
5308 | mmdrop(mm); | |
5309 | } | |
5310 | ||
054b9108 | 5311 | /* called under rq->lock with disabled interrupts */ |
36c8b586 | 5312 | static void migrate_dead(unsigned int dead_cpu, struct task_struct *p) |
1da177e4 | 5313 | { |
70b97a7f | 5314 | struct rq *rq = cpu_rq(dead_cpu); |
1da177e4 LT |
5315 | |
5316 | /* Must be exiting, otherwise would be on tasklist. */ | |
270f722d | 5317 | BUG_ON(!p->exit_state); |
1da177e4 LT |
5318 | |
5319 | /* Cannot have done final schedule yet: would have vanished. */ | |
c394cc9f | 5320 | BUG_ON(p->state == TASK_DEAD); |
1da177e4 | 5321 | |
48f24c4d | 5322 | get_task_struct(p); |
1da177e4 LT |
5323 | |
5324 | /* | |
5325 | * Drop lock around migration; if someone else moves it, | |
41a2d6cf | 5326 | * that's OK. No task can be added to this CPU, so iteration is |
1da177e4 LT |
5327 | * fine. |
5328 | */ | |
f7b4cddc | 5329 | spin_unlock_irq(&rq->lock); |
48f24c4d | 5330 | move_task_off_dead_cpu(dead_cpu, p); |
f7b4cddc | 5331 | spin_lock_irq(&rq->lock); |
1da177e4 | 5332 | |
48f24c4d | 5333 | put_task_struct(p); |
1da177e4 LT |
5334 | } |
5335 | ||
5336 | /* release_task() removes task from tasklist, so we won't find dead tasks. */ | |
5337 | static void migrate_dead_tasks(unsigned int dead_cpu) | |
5338 | { | |
70b97a7f | 5339 | struct rq *rq = cpu_rq(dead_cpu); |
dd41f596 | 5340 | struct task_struct *next; |
48f24c4d | 5341 | |
dd41f596 IM |
5342 | for ( ; ; ) { |
5343 | if (!rq->nr_running) | |
5344 | break; | |
a8e504d2 | 5345 | update_rq_clock(rq); |
ff95f3df | 5346 | next = pick_next_task(rq, rq->curr); |
dd41f596 IM |
5347 | if (!next) |
5348 | break; | |
5349 | migrate_dead(dead_cpu, next); | |
e692ab53 | 5350 | |
1da177e4 LT |
5351 | } |
5352 | } | |
5353 | #endif /* CONFIG_HOTPLUG_CPU */ | |
5354 | ||
e692ab53 NP |
5355 | #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL) |
5356 | ||
5357 | static struct ctl_table sd_ctl_dir[] = { | |
e0361851 AD |
5358 | { |
5359 | .procname = "sched_domain", | |
c57baf1e | 5360 | .mode = 0555, |
e0361851 | 5361 | }, |
38605cae | 5362 | {0, }, |
e692ab53 NP |
5363 | }; |
5364 | ||
5365 | static struct ctl_table sd_ctl_root[] = { | |
e0361851 | 5366 | { |
c57baf1e | 5367 | .ctl_name = CTL_KERN, |
e0361851 | 5368 | .procname = "kernel", |
c57baf1e | 5369 | .mode = 0555, |
e0361851 AD |
5370 | .child = sd_ctl_dir, |
5371 | }, | |
38605cae | 5372 | {0, }, |
e692ab53 NP |
5373 | }; |
5374 | ||
5375 | static struct ctl_table *sd_alloc_ctl_entry(int n) | |
5376 | { | |
5377 | struct ctl_table *entry = | |
5cf9f062 | 5378 | kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL); |
e692ab53 | 5379 | |
e692ab53 NP |
5380 | return entry; |
5381 | } | |
5382 | ||
6382bc90 MM |
5383 | static void sd_free_ctl_entry(struct ctl_table **tablep) |
5384 | { | |
cd790076 | 5385 | struct ctl_table *entry; |
6382bc90 | 5386 | |
cd790076 MM |
5387 | /* |
5388 | * In the intermediate directories, both the child directory and | |
5389 | * procname are dynamically allocated and could fail but the mode | |
41a2d6cf | 5390 | * will always be set. In the lowest directory the names are |
cd790076 MM |
5391 | * static strings and all have proc handlers. |
5392 | */ | |
5393 | for (entry = *tablep; entry->mode; entry++) { | |
6382bc90 MM |
5394 | if (entry->child) |
5395 | sd_free_ctl_entry(&entry->child); | |
cd790076 MM |
5396 | if (entry->proc_handler == NULL) |
5397 | kfree(entry->procname); | |
5398 | } | |
6382bc90 MM |
5399 | |
5400 | kfree(*tablep); | |
5401 | *tablep = NULL; | |
5402 | } | |
5403 | ||
e692ab53 | 5404 | static void |
e0361851 | 5405 | set_table_entry(struct ctl_table *entry, |
e692ab53 NP |
5406 | const char *procname, void *data, int maxlen, |
5407 | mode_t mode, proc_handler *proc_handler) | |
5408 | { | |
e692ab53 NP |
5409 | entry->procname = procname; |
5410 | entry->data = data; | |
5411 | entry->maxlen = maxlen; | |
5412 | entry->mode = mode; | |
5413 | entry->proc_handler = proc_handler; | |
5414 | } | |
5415 | ||
5416 | static struct ctl_table * | |
5417 | sd_alloc_ctl_domain_table(struct sched_domain *sd) | |
5418 | { | |
ace8b3d6 | 5419 | struct ctl_table *table = sd_alloc_ctl_entry(12); |
e692ab53 | 5420 | |
ad1cdc1d MM |
5421 | if (table == NULL) |
5422 | return NULL; | |
5423 | ||
e0361851 | 5424 | set_table_entry(&table[0], "min_interval", &sd->min_interval, |
e692ab53 | 5425 | sizeof(long), 0644, proc_doulongvec_minmax); |
e0361851 | 5426 | set_table_entry(&table[1], "max_interval", &sd->max_interval, |
e692ab53 | 5427 | sizeof(long), 0644, proc_doulongvec_minmax); |
e0361851 | 5428 | set_table_entry(&table[2], "busy_idx", &sd->busy_idx, |
e692ab53 | 5429 | sizeof(int), 0644, proc_dointvec_minmax); |
e0361851 | 5430 | set_table_entry(&table[3], "idle_idx", &sd->idle_idx, |
e692ab53 | 5431 | sizeof(int), 0644, proc_dointvec_minmax); |
e0361851 | 5432 | set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx, |
e692ab53 | 5433 | sizeof(int), 0644, proc_dointvec_minmax); |
e0361851 | 5434 | set_table_entry(&table[5], "wake_idx", &sd->wake_idx, |
e692ab53 | 5435 | sizeof(int), 0644, proc_dointvec_minmax); |
e0361851 | 5436 | set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx, |
e692ab53 | 5437 | sizeof(int), 0644, proc_dointvec_minmax); |
e0361851 | 5438 | set_table_entry(&table[7], "busy_factor", &sd->busy_factor, |
e692ab53 | 5439 | sizeof(int), 0644, proc_dointvec_minmax); |
e0361851 | 5440 | set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct, |
e692ab53 | 5441 | sizeof(int), 0644, proc_dointvec_minmax); |
ace8b3d6 | 5442 | set_table_entry(&table[9], "cache_nice_tries", |
e692ab53 NP |
5443 | &sd->cache_nice_tries, |
5444 | sizeof(int), 0644, proc_dointvec_minmax); | |
ace8b3d6 | 5445 | set_table_entry(&table[10], "flags", &sd->flags, |
e692ab53 | 5446 | sizeof(int), 0644, proc_dointvec_minmax); |
6323469f | 5447 | /* &table[11] is terminator */ |
e692ab53 NP |
5448 | |
5449 | return table; | |
5450 | } | |
5451 | ||
9a4e7159 | 5452 | static ctl_table *sd_alloc_ctl_cpu_table(int cpu) |
e692ab53 NP |
5453 | { |
5454 | struct ctl_table *entry, *table; | |
5455 | struct sched_domain *sd; | |
5456 | int domain_num = 0, i; | |
5457 | char buf[32]; | |
5458 | ||
5459 | for_each_domain(cpu, sd) | |
5460 | domain_num++; | |
5461 | entry = table = sd_alloc_ctl_entry(domain_num + 1); | |
ad1cdc1d MM |
5462 | if (table == NULL) |
5463 | return NULL; | |
e692ab53 NP |
5464 | |
5465 | i = 0; | |
5466 | for_each_domain(cpu, sd) { | |
5467 | snprintf(buf, 32, "domain%d", i); | |
e692ab53 | 5468 | entry->procname = kstrdup(buf, GFP_KERNEL); |
c57baf1e | 5469 | entry->mode = 0555; |
e692ab53 NP |
5470 | entry->child = sd_alloc_ctl_domain_table(sd); |
5471 | entry++; | |
5472 | i++; | |
5473 | } | |
5474 | return table; | |
5475 | } | |
5476 | ||
5477 | static struct ctl_table_header *sd_sysctl_header; | |
6382bc90 | 5478 | static void register_sched_domain_sysctl(void) |
e692ab53 NP |
5479 | { |
5480 | int i, cpu_num = num_online_cpus(); | |
5481 | struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1); | |
5482 | char buf[32]; | |
5483 | ||
7378547f MM |
5484 | WARN_ON(sd_ctl_dir[0].child); |
5485 | sd_ctl_dir[0].child = entry; | |
5486 | ||
ad1cdc1d MM |
5487 | if (entry == NULL) |
5488 | return; | |
5489 | ||
97b6ea7b | 5490 | for_each_online_cpu(i) { |
e692ab53 | 5491 | snprintf(buf, 32, "cpu%d", i); |
e692ab53 | 5492 | entry->procname = kstrdup(buf, GFP_KERNEL); |
c57baf1e | 5493 | entry->mode = 0555; |
e692ab53 | 5494 | entry->child = sd_alloc_ctl_cpu_table(i); |
97b6ea7b | 5495 | entry++; |
e692ab53 | 5496 | } |
7378547f MM |
5497 | |
5498 | WARN_ON(sd_sysctl_header); | |
e692ab53 NP |
5499 | sd_sysctl_header = register_sysctl_table(sd_ctl_root); |
5500 | } | |
6382bc90 | 5501 | |
7378547f | 5502 | /* may be called multiple times per register */ |
6382bc90 MM |
5503 | static void unregister_sched_domain_sysctl(void) |
5504 | { | |
7378547f MM |
5505 | if (sd_sysctl_header) |
5506 | unregister_sysctl_table(sd_sysctl_header); | |
6382bc90 | 5507 | sd_sysctl_header = NULL; |
7378547f MM |
5508 | if (sd_ctl_dir[0].child) |
5509 | sd_free_ctl_entry(&sd_ctl_dir[0].child); | |
6382bc90 | 5510 | } |
e692ab53 | 5511 | #else |
6382bc90 MM |
5512 | static void register_sched_domain_sysctl(void) |
5513 | { | |
5514 | } | |
5515 | static void unregister_sched_domain_sysctl(void) | |
e692ab53 NP |
5516 | { |
5517 | } | |
5518 | #endif | |
5519 | ||
1da177e4 LT |
5520 | /* |
5521 | * migration_call - callback that gets triggered when a CPU is added. | |
5522 | * Here we can start up the necessary migration thread for the new CPU. | |
5523 | */ | |
48f24c4d IM |
5524 | static int __cpuinit |
5525 | migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) | |
1da177e4 | 5526 | { |
1da177e4 | 5527 | struct task_struct *p; |
48f24c4d | 5528 | int cpu = (long)hcpu; |
1da177e4 | 5529 | unsigned long flags; |
70b97a7f | 5530 | struct rq *rq; |
1da177e4 LT |
5531 | |
5532 | switch (action) { | |
5be9361c | 5533 | |
1da177e4 | 5534 | case CPU_UP_PREPARE: |
8bb78442 | 5535 | case CPU_UP_PREPARE_FROZEN: |
dd41f596 | 5536 | p = kthread_create(migration_thread, hcpu, "migration/%d", cpu); |
1da177e4 LT |
5537 | if (IS_ERR(p)) |
5538 | return NOTIFY_BAD; | |
1da177e4 LT |
5539 | kthread_bind(p, cpu); |
5540 | /* Must be high prio: stop_machine expects to yield to it. */ | |
5541 | rq = task_rq_lock(p, &flags); | |
dd41f596 | 5542 | __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1); |
1da177e4 LT |
5543 | task_rq_unlock(rq, &flags); |
5544 | cpu_rq(cpu)->migration_thread = p; | |
5545 | break; | |
48f24c4d | 5546 | |
1da177e4 | 5547 | case CPU_ONLINE: |
8bb78442 | 5548 | case CPU_ONLINE_FROZEN: |
3a4fa0a2 | 5549 | /* Strictly unnecessary, as first user will wake it. */ |
1da177e4 LT |
5550 | wake_up_process(cpu_rq(cpu)->migration_thread); |
5551 | break; | |
48f24c4d | 5552 | |
1da177e4 LT |
5553 | #ifdef CONFIG_HOTPLUG_CPU |
5554 | case CPU_UP_CANCELED: | |
8bb78442 | 5555 | case CPU_UP_CANCELED_FROZEN: |
fc75cdfa HC |
5556 | if (!cpu_rq(cpu)->migration_thread) |
5557 | break; | |
41a2d6cf | 5558 | /* Unbind it from offline cpu so it can run. Fall thru. */ |
a4c4af7c HC |
5559 | kthread_bind(cpu_rq(cpu)->migration_thread, |
5560 | any_online_cpu(cpu_online_map)); | |
1da177e4 LT |
5561 | kthread_stop(cpu_rq(cpu)->migration_thread); |
5562 | cpu_rq(cpu)->migration_thread = NULL; | |
5563 | break; | |
48f24c4d | 5564 | |
1da177e4 | 5565 | case CPU_DEAD: |
8bb78442 | 5566 | case CPU_DEAD_FROZEN: |
470fd646 | 5567 | cpuset_lock(); /* around calls to cpuset_cpus_allowed_lock() */ |
1da177e4 LT |
5568 | migrate_live_tasks(cpu); |
5569 | rq = cpu_rq(cpu); | |
5570 | kthread_stop(rq->migration_thread); | |
5571 | rq->migration_thread = NULL; | |
5572 | /* Idle task back to normal (off runqueue, low prio) */ | |
d2da272a | 5573 | spin_lock_irq(&rq->lock); |
a8e504d2 | 5574 | update_rq_clock(rq); |
2e1cb74a | 5575 | deactivate_task(rq, rq->idle, 0); |
1da177e4 | 5576 | rq->idle->static_prio = MAX_PRIO; |
dd41f596 IM |
5577 | __setscheduler(rq, rq->idle, SCHED_NORMAL, 0); |
5578 | rq->idle->sched_class = &idle_sched_class; | |
1da177e4 | 5579 | migrate_dead_tasks(cpu); |
d2da272a | 5580 | spin_unlock_irq(&rq->lock); |
470fd646 | 5581 | cpuset_unlock(); |
1da177e4 LT |
5582 | migrate_nr_uninterruptible(rq); |
5583 | BUG_ON(rq->nr_running != 0); | |
5584 | ||
41a2d6cf IM |
5585 | /* |
5586 | * No need to migrate the tasks: it was best-effort if | |
5587 | * they didn't take sched_hotcpu_mutex. Just wake up | |
5588 | * the requestors. | |
5589 | */ | |
1da177e4 LT |
5590 | spin_lock_irq(&rq->lock); |
5591 | while (!list_empty(&rq->migration_queue)) { | |
70b97a7f IM |
5592 | struct migration_req *req; |
5593 | ||
1da177e4 | 5594 | req = list_entry(rq->migration_queue.next, |
70b97a7f | 5595 | struct migration_req, list); |
1da177e4 LT |
5596 | list_del_init(&req->list); |
5597 | complete(&req->done); | |
5598 | } | |
5599 | spin_unlock_irq(&rq->lock); | |
5600 | break; | |
5601 | #endif | |
5602 | } | |
5603 | return NOTIFY_OK; | |
5604 | } | |
5605 | ||
5606 | /* Register at highest priority so that task migration (migrate_all_tasks) | |
5607 | * happens before everything else. | |
5608 | */ | |
26c2143b | 5609 | static struct notifier_block __cpuinitdata migration_notifier = { |
1da177e4 LT |
5610 | .notifier_call = migration_call, |
5611 | .priority = 10 | |
5612 | }; | |
5613 | ||
e6fe6649 | 5614 | void __init migration_init(void) |
1da177e4 LT |
5615 | { |
5616 | void *cpu = (void *)(long)smp_processor_id(); | |
07dccf33 | 5617 | int err; |
48f24c4d IM |
5618 | |
5619 | /* Start one for the boot CPU: */ | |
07dccf33 AM |
5620 | err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu); |
5621 | BUG_ON(err == NOTIFY_BAD); | |
1da177e4 LT |
5622 | migration_call(&migration_notifier, CPU_ONLINE, cpu); |
5623 | register_cpu_notifier(&migration_notifier); | |
1da177e4 LT |
5624 | } |
5625 | #endif | |
5626 | ||
5627 | #ifdef CONFIG_SMP | |
476f3534 CL |
5628 | |
5629 | /* Number of possible processor ids */ | |
5630 | int nr_cpu_ids __read_mostly = NR_CPUS; | |
5631 | EXPORT_SYMBOL(nr_cpu_ids); | |
5632 | ||
3e9830dc | 5633 | #ifdef CONFIG_SCHED_DEBUG |
4dcf6aff IM |
5634 | |
5635 | static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level) | |
1da177e4 | 5636 | { |
4dcf6aff IM |
5637 | struct sched_group *group = sd->groups; |
5638 | cpumask_t groupmask; | |
5639 | char str[NR_CPUS]; | |
1da177e4 | 5640 | |
4dcf6aff IM |
5641 | cpumask_scnprintf(str, NR_CPUS, sd->span); |
5642 | cpus_clear(groupmask); | |
5643 | ||
5644 | printk(KERN_DEBUG "%*s domain %d: ", level, "", level); | |
5645 | ||
5646 | if (!(sd->flags & SD_LOAD_BALANCE)) { | |
5647 | printk("does not load-balance\n"); | |
5648 | if (sd->parent) | |
5649 | printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain" | |
5650 | " has parent"); | |
5651 | return -1; | |
41c7ce9a NP |
5652 | } |
5653 | ||
4dcf6aff IM |
5654 | printk(KERN_CONT "span %s\n", str); |
5655 | ||
5656 | if (!cpu_isset(cpu, sd->span)) { | |
5657 | printk(KERN_ERR "ERROR: domain->span does not contain " | |
5658 | "CPU%d\n", cpu); | |
5659 | } | |
5660 | if (!cpu_isset(cpu, group->cpumask)) { | |
5661 | printk(KERN_ERR "ERROR: domain->groups does not contain" | |
5662 | " CPU%d\n", cpu); | |
5663 | } | |
1da177e4 | 5664 | |
4dcf6aff | 5665 | printk(KERN_DEBUG "%*s groups:", level + 1, ""); |
1da177e4 | 5666 | do { |
4dcf6aff IM |
5667 | if (!group) { |
5668 | printk("\n"); | |
5669 | printk(KERN_ERR "ERROR: group is NULL\n"); | |
1da177e4 LT |
5670 | break; |
5671 | } | |
5672 | ||
4dcf6aff IM |
5673 | if (!group->__cpu_power) { |
5674 | printk(KERN_CONT "\n"); | |
5675 | printk(KERN_ERR "ERROR: domain->cpu_power not " | |
5676 | "set\n"); | |
5677 | break; | |
5678 | } | |
1da177e4 | 5679 | |
4dcf6aff IM |
5680 | if (!cpus_weight(group->cpumask)) { |
5681 | printk(KERN_CONT "\n"); | |
5682 | printk(KERN_ERR "ERROR: empty group\n"); | |
5683 | break; | |
5684 | } | |
1da177e4 | 5685 | |
4dcf6aff IM |
5686 | if (cpus_intersects(groupmask, group->cpumask)) { |
5687 | printk(KERN_CONT "\n"); | |
5688 | printk(KERN_ERR "ERROR: repeated CPUs\n"); | |
5689 | break; | |
5690 | } | |
1da177e4 | 5691 | |
4dcf6aff | 5692 | cpus_or(groupmask, groupmask, group->cpumask); |
1da177e4 | 5693 | |
4dcf6aff IM |
5694 | cpumask_scnprintf(str, NR_CPUS, group->cpumask); |
5695 | printk(KERN_CONT " %s", str); | |
1da177e4 | 5696 | |
4dcf6aff IM |
5697 | group = group->next; |
5698 | } while (group != sd->groups); | |
5699 | printk(KERN_CONT "\n"); | |
1da177e4 | 5700 | |
4dcf6aff IM |
5701 | if (!cpus_equal(sd->span, groupmask)) |
5702 | printk(KERN_ERR "ERROR: groups don't span domain->span\n"); | |
1da177e4 | 5703 | |
4dcf6aff IM |
5704 | if (sd->parent && !cpus_subset(groupmask, sd->parent->span)) |
5705 | printk(KERN_ERR "ERROR: parent span is not a superset " | |
5706 | "of domain->span\n"); | |
5707 | return 0; | |
5708 | } | |
1da177e4 | 5709 | |
4dcf6aff IM |
5710 | static void sched_domain_debug(struct sched_domain *sd, int cpu) |
5711 | { | |
5712 | int level = 0; | |
1da177e4 | 5713 | |
4dcf6aff IM |
5714 | if (!sd) { |
5715 | printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu); | |
5716 | return; | |
5717 | } | |
1da177e4 | 5718 | |
4dcf6aff IM |
5719 | printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu); |
5720 | ||
5721 | for (;;) { | |
5722 | if (sched_domain_debug_one(sd, cpu, level)) | |
5723 | break; | |
1da177e4 LT |
5724 | level++; |
5725 | sd = sd->parent; | |
33859f7f | 5726 | if (!sd) |
4dcf6aff IM |
5727 | break; |
5728 | } | |
1da177e4 LT |
5729 | } |
5730 | #else | |
48f24c4d | 5731 | # define sched_domain_debug(sd, cpu) do { } while (0) |
1da177e4 LT |
5732 | #endif |
5733 | ||
1a20ff27 | 5734 | static int sd_degenerate(struct sched_domain *sd) |
245af2c7 SS |
5735 | { |
5736 | if (cpus_weight(sd->span) == 1) | |
5737 | return 1; | |
5738 | ||
5739 | /* Following flags need at least 2 groups */ | |
5740 | if (sd->flags & (SD_LOAD_BALANCE | | |
5741 | SD_BALANCE_NEWIDLE | | |
5742 | SD_BALANCE_FORK | | |
89c4710e SS |
5743 | SD_BALANCE_EXEC | |
5744 | SD_SHARE_CPUPOWER | | |
5745 | SD_SHARE_PKG_RESOURCES)) { | |
245af2c7 SS |
5746 | if (sd->groups != sd->groups->next) |
5747 | return 0; | |
5748 | } | |
5749 | ||
5750 | /* Following flags don't use groups */ | |
5751 | if (sd->flags & (SD_WAKE_IDLE | | |
5752 | SD_WAKE_AFFINE | | |
5753 | SD_WAKE_BALANCE)) | |
5754 | return 0; | |
5755 | ||
5756 | return 1; | |
5757 | } | |
5758 | ||
48f24c4d IM |
5759 | static int |
5760 | sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent) | |
245af2c7 SS |
5761 | { |
5762 | unsigned long cflags = sd->flags, pflags = parent->flags; | |
5763 | ||
5764 | if (sd_degenerate(parent)) | |
5765 | return 1; | |
5766 | ||
5767 | if (!cpus_equal(sd->span, parent->span)) | |
5768 | return 0; | |
5769 | ||
5770 | /* Does parent contain flags not in child? */ | |
5771 | /* WAKE_BALANCE is a subset of WAKE_AFFINE */ | |
5772 | if (cflags & SD_WAKE_AFFINE) | |
5773 | pflags &= ~SD_WAKE_BALANCE; | |
5774 | /* Flags needing groups don't count if only 1 group in parent */ | |
5775 | if (parent->groups == parent->groups->next) { | |
5776 | pflags &= ~(SD_LOAD_BALANCE | | |
5777 | SD_BALANCE_NEWIDLE | | |
5778 | SD_BALANCE_FORK | | |
89c4710e SS |
5779 | SD_BALANCE_EXEC | |
5780 | SD_SHARE_CPUPOWER | | |
5781 | SD_SHARE_PKG_RESOURCES); | |
245af2c7 SS |
5782 | } |
5783 | if (~cflags & pflags) | |
5784 | return 0; | |
5785 | ||
5786 | return 1; | |
5787 | } | |
5788 | ||
1da177e4 LT |
5789 | /* |
5790 | * Attach the domain 'sd' to 'cpu' as its base domain. Callers must | |
5791 | * hold the hotplug lock. | |
5792 | */ | |
9c1cfda2 | 5793 | static void cpu_attach_domain(struct sched_domain *sd, int cpu) |
1da177e4 | 5794 | { |
70b97a7f | 5795 | struct rq *rq = cpu_rq(cpu); |
245af2c7 SS |
5796 | struct sched_domain *tmp; |
5797 | ||
5798 | /* Remove the sched domains which do not contribute to scheduling. */ | |
5799 | for (tmp = sd; tmp; tmp = tmp->parent) { | |
5800 | struct sched_domain *parent = tmp->parent; | |
5801 | if (!parent) | |
5802 | break; | |
1a848870 | 5803 | if (sd_parent_degenerate(tmp, parent)) { |
245af2c7 | 5804 | tmp->parent = parent->parent; |
1a848870 SS |
5805 | if (parent->parent) |
5806 | parent->parent->child = tmp; | |
5807 | } | |
245af2c7 SS |
5808 | } |
5809 | ||
1a848870 | 5810 | if (sd && sd_degenerate(sd)) { |
245af2c7 | 5811 | sd = sd->parent; |
1a848870 SS |
5812 | if (sd) |
5813 | sd->child = NULL; | |
5814 | } | |
1da177e4 LT |
5815 | |
5816 | sched_domain_debug(sd, cpu); | |
5817 | ||
674311d5 | 5818 | rcu_assign_pointer(rq->sd, sd); |
1da177e4 LT |
5819 | } |
5820 | ||
5821 | /* cpus with isolated domains */ | |
67af63a6 | 5822 | static cpumask_t cpu_isolated_map = CPU_MASK_NONE; |
1da177e4 LT |
5823 | |
5824 | /* Setup the mask of cpus configured for isolated domains */ | |
5825 | static int __init isolated_cpu_setup(char *str) | |
5826 | { | |
5827 | int ints[NR_CPUS], i; | |
5828 | ||
5829 | str = get_options(str, ARRAY_SIZE(ints), ints); | |
5830 | cpus_clear(cpu_isolated_map); | |
5831 | for (i = 1; i <= ints[0]; i++) | |
5832 | if (ints[i] < NR_CPUS) | |
5833 | cpu_set(ints[i], cpu_isolated_map); | |
5834 | return 1; | |
5835 | } | |
5836 | ||
8927f494 | 5837 | __setup("isolcpus=", isolated_cpu_setup); |
1da177e4 LT |
5838 | |
5839 | /* | |
6711cab4 SS |
5840 | * init_sched_build_groups takes the cpumask we wish to span, and a pointer |
5841 | * to a function which identifies what group(along with sched group) a CPU | |
5842 | * belongs to. The return value of group_fn must be a >= 0 and < NR_CPUS | |
5843 | * (due to the fact that we keep track of groups covered with a cpumask_t). | |
1da177e4 LT |
5844 | * |
5845 | * init_sched_build_groups will build a circular linked list of the groups | |
5846 | * covered by the given span, and will set each group's ->cpumask correctly, | |
5847 | * and ->cpu_power to 0. | |
5848 | */ | |
a616058b | 5849 | static void |
6711cab4 SS |
5850 | init_sched_build_groups(cpumask_t span, const cpumask_t *cpu_map, |
5851 | int (*group_fn)(int cpu, const cpumask_t *cpu_map, | |
5852 | struct sched_group **sg)) | |
1da177e4 LT |
5853 | { |
5854 | struct sched_group *first = NULL, *last = NULL; | |
5855 | cpumask_t covered = CPU_MASK_NONE; | |
5856 | int i; | |
5857 | ||
5858 | for_each_cpu_mask(i, span) { | |
6711cab4 SS |
5859 | struct sched_group *sg; |
5860 | int group = group_fn(i, cpu_map, &sg); | |
1da177e4 LT |
5861 | int j; |
5862 | ||
5863 | if (cpu_isset(i, covered)) | |
5864 | continue; | |
5865 | ||
5866 | sg->cpumask = CPU_MASK_NONE; | |
5517d86b | 5867 | sg->__cpu_power = 0; |
1da177e4 LT |
5868 | |
5869 | for_each_cpu_mask(j, span) { | |
6711cab4 | 5870 | if (group_fn(j, cpu_map, NULL) != group) |
1da177e4 LT |
5871 | continue; |
5872 | ||
5873 | cpu_set(j, covered); | |
5874 | cpu_set(j, sg->cpumask); | |
5875 | } | |
5876 | if (!first) | |
5877 | first = sg; | |
5878 | if (last) | |
5879 | last->next = sg; | |
5880 | last = sg; | |
5881 | } | |
5882 | last->next = first; | |
5883 | } | |
5884 | ||
9c1cfda2 | 5885 | #define SD_NODES_PER_DOMAIN 16 |
1da177e4 | 5886 | |
9c1cfda2 | 5887 | #ifdef CONFIG_NUMA |
198e2f18 | 5888 | |
9c1cfda2 JH |
5889 | /** |
5890 | * find_next_best_node - find the next node to include in a sched_domain | |
5891 | * @node: node whose sched_domain we're building | |
5892 | * @used_nodes: nodes already in the sched_domain | |
5893 | * | |
41a2d6cf | 5894 | * Find the next node to include in a given scheduling domain. Simply |
9c1cfda2 JH |
5895 | * finds the closest node not already in the @used_nodes map. |
5896 | * | |
5897 | * Should use nodemask_t. | |
5898 | */ | |
5899 | static int find_next_best_node(int node, unsigned long *used_nodes) | |
5900 | { | |
5901 | int i, n, val, min_val, best_node = 0; | |
5902 | ||
5903 | min_val = INT_MAX; | |
5904 | ||
5905 | for (i = 0; i < MAX_NUMNODES; i++) { | |
5906 | /* Start at @node */ | |
5907 | n = (node + i) % MAX_NUMNODES; | |
5908 | ||
5909 | if (!nr_cpus_node(n)) | |
5910 | continue; | |
5911 | ||
5912 | /* Skip already used nodes */ | |
5913 | if (test_bit(n, used_nodes)) | |
5914 | continue; | |
5915 | ||
5916 | /* Simple min distance search */ | |
5917 | val = node_distance(node, n); | |
5918 | ||
5919 | if (val < min_val) { | |
5920 | min_val = val; | |
5921 | best_node = n; | |
5922 | } | |
5923 | } | |
5924 | ||
5925 | set_bit(best_node, used_nodes); | |
5926 | return best_node; | |
5927 | } | |
5928 | ||
5929 | /** | |
5930 | * sched_domain_node_span - get a cpumask for a node's sched_domain | |
5931 | * @node: node whose cpumask we're constructing | |
5932 | * @size: number of nodes to include in this span | |
5933 | * | |
41a2d6cf | 5934 | * Given a node, construct a good cpumask for its sched_domain to span. It |
9c1cfda2 JH |
5935 | * should be one that prevents unnecessary balancing, but also spreads tasks |
5936 | * out optimally. | |
5937 | */ | |
5938 | static cpumask_t sched_domain_node_span(int node) | |
5939 | { | |
9c1cfda2 | 5940 | DECLARE_BITMAP(used_nodes, MAX_NUMNODES); |
48f24c4d IM |
5941 | cpumask_t span, nodemask; |
5942 | int i; | |
9c1cfda2 JH |
5943 | |
5944 | cpus_clear(span); | |
5945 | bitmap_zero(used_nodes, MAX_NUMNODES); | |
5946 | ||
5947 | nodemask = node_to_cpumask(node); | |
5948 | cpus_or(span, span, nodemask); | |
5949 | set_bit(node, used_nodes); | |
5950 | ||
5951 | for (i = 1; i < SD_NODES_PER_DOMAIN; i++) { | |
5952 | int next_node = find_next_best_node(node, used_nodes); | |
48f24c4d | 5953 | |
9c1cfda2 JH |
5954 | nodemask = node_to_cpumask(next_node); |
5955 | cpus_or(span, span, nodemask); | |
5956 | } | |
5957 | ||
5958 | return span; | |
5959 | } | |
5960 | #endif | |
5961 | ||
5c45bf27 | 5962 | int sched_smt_power_savings = 0, sched_mc_power_savings = 0; |
48f24c4d | 5963 | |
9c1cfda2 | 5964 | /* |
48f24c4d | 5965 | * SMT sched-domains: |
9c1cfda2 | 5966 | */ |
1da177e4 LT |
5967 | #ifdef CONFIG_SCHED_SMT |
5968 | static DEFINE_PER_CPU(struct sched_domain, cpu_domains); | |
6711cab4 | 5969 | static DEFINE_PER_CPU(struct sched_group, sched_group_cpus); |
48f24c4d | 5970 | |
41a2d6cf IM |
5971 | static int |
5972 | cpu_to_cpu_group(int cpu, const cpumask_t *cpu_map, struct sched_group **sg) | |
1da177e4 | 5973 | { |
6711cab4 SS |
5974 | if (sg) |
5975 | *sg = &per_cpu(sched_group_cpus, cpu); | |
1da177e4 LT |
5976 | return cpu; |
5977 | } | |
5978 | #endif | |
5979 | ||
48f24c4d IM |
5980 | /* |
5981 | * multi-core sched-domains: | |
5982 | */ | |
1e9f28fa SS |
5983 | #ifdef CONFIG_SCHED_MC |
5984 | static DEFINE_PER_CPU(struct sched_domain, core_domains); | |
6711cab4 | 5985 | static DEFINE_PER_CPU(struct sched_group, sched_group_core); |
1e9f28fa SS |
5986 | #endif |
5987 | ||
5988 | #if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT) | |
41a2d6cf IM |
5989 | static int |
5990 | cpu_to_core_group(int cpu, const cpumask_t *cpu_map, struct sched_group **sg) | |
1e9f28fa | 5991 | { |
6711cab4 | 5992 | int group; |
d5a7430d | 5993 | cpumask_t mask = per_cpu(cpu_sibling_map, cpu); |
a616058b | 5994 | cpus_and(mask, mask, *cpu_map); |
6711cab4 SS |
5995 | group = first_cpu(mask); |
5996 | if (sg) | |
5997 | *sg = &per_cpu(sched_group_core, group); | |
5998 | return group; | |
1e9f28fa SS |
5999 | } |
6000 | #elif defined(CONFIG_SCHED_MC) | |
41a2d6cf IM |
6001 | static int |
6002 | cpu_to_core_group(int cpu, const cpumask_t *cpu_map, struct sched_group **sg) | |
1e9f28fa | 6003 | { |
6711cab4 SS |
6004 | if (sg) |
6005 | *sg = &per_cpu(sched_group_core, cpu); | |
1e9f28fa SS |
6006 | return cpu; |
6007 | } | |
6008 | #endif | |
6009 | ||
1da177e4 | 6010 | static DEFINE_PER_CPU(struct sched_domain, phys_domains); |
6711cab4 | 6011 | static DEFINE_PER_CPU(struct sched_group, sched_group_phys); |
48f24c4d | 6012 | |
41a2d6cf IM |
6013 | static int |
6014 | cpu_to_phys_group(int cpu, const cpumask_t *cpu_map, struct sched_group **sg) | |
1da177e4 | 6015 | { |
6711cab4 | 6016 | int group; |
48f24c4d | 6017 | #ifdef CONFIG_SCHED_MC |
1e9f28fa | 6018 | cpumask_t mask = cpu_coregroup_map(cpu); |
a616058b | 6019 | cpus_and(mask, mask, *cpu_map); |
6711cab4 | 6020 | group = first_cpu(mask); |
1e9f28fa | 6021 | #elif defined(CONFIG_SCHED_SMT) |
d5a7430d | 6022 | cpumask_t mask = per_cpu(cpu_sibling_map, cpu); |
a616058b | 6023 | cpus_and(mask, mask, *cpu_map); |
6711cab4 | 6024 | group = first_cpu(mask); |
1da177e4 | 6025 | #else |
6711cab4 | 6026 | group = cpu; |
1da177e4 | 6027 | #endif |
6711cab4 SS |
6028 | if (sg) |
6029 | *sg = &per_cpu(sched_group_phys, group); | |
6030 | return group; | |
1da177e4 LT |
6031 | } |
6032 | ||
6033 | #ifdef CONFIG_NUMA | |
1da177e4 | 6034 | /* |
9c1cfda2 JH |
6035 | * The init_sched_build_groups can't handle what we want to do with node |
6036 | * groups, so roll our own. Now each node has its own list of groups which | |
6037 | * gets dynamically allocated. | |
1da177e4 | 6038 | */ |
9c1cfda2 | 6039 | static DEFINE_PER_CPU(struct sched_domain, node_domains); |
d1b55138 | 6040 | static struct sched_group **sched_group_nodes_bycpu[NR_CPUS]; |
1da177e4 | 6041 | |
9c1cfda2 | 6042 | static DEFINE_PER_CPU(struct sched_domain, allnodes_domains); |
6711cab4 | 6043 | static DEFINE_PER_CPU(struct sched_group, sched_group_allnodes); |
9c1cfda2 | 6044 | |
6711cab4 SS |
6045 | static int cpu_to_allnodes_group(int cpu, const cpumask_t *cpu_map, |
6046 | struct sched_group **sg) | |
9c1cfda2 | 6047 | { |
6711cab4 SS |
6048 | cpumask_t nodemask = node_to_cpumask(cpu_to_node(cpu)); |
6049 | int group; | |
6050 | ||
6051 | cpus_and(nodemask, nodemask, *cpu_map); | |
6052 | group = first_cpu(nodemask); | |
6053 | ||
6054 | if (sg) | |
6055 | *sg = &per_cpu(sched_group_allnodes, group); | |
6056 | return group; | |
1da177e4 | 6057 | } |
6711cab4 | 6058 | |
08069033 SS |
6059 | static void init_numa_sched_groups_power(struct sched_group *group_head) |
6060 | { | |
6061 | struct sched_group *sg = group_head; | |
6062 | int j; | |
6063 | ||
6064 | if (!sg) | |
6065 | return; | |
3a5c359a AK |
6066 | do { |
6067 | for_each_cpu_mask(j, sg->cpumask) { | |
6068 | struct sched_domain *sd; | |
08069033 | 6069 | |
3a5c359a AK |
6070 | sd = &per_cpu(phys_domains, j); |
6071 | if (j != first_cpu(sd->groups->cpumask)) { | |
6072 | /* | |
6073 | * Only add "power" once for each | |
6074 | * physical package. | |
6075 | */ | |
6076 | continue; | |
6077 | } | |
08069033 | 6078 | |
3a5c359a AK |
6079 | sg_inc_cpu_power(sg, sd->groups->__cpu_power); |
6080 | } | |
6081 | sg = sg->next; | |
6082 | } while (sg != group_head); | |
08069033 | 6083 | } |
1da177e4 LT |
6084 | #endif |
6085 | ||
a616058b | 6086 | #ifdef CONFIG_NUMA |
51888ca2 SV |
6087 | /* Free memory allocated for various sched_group structures */ |
6088 | static void free_sched_groups(const cpumask_t *cpu_map) | |
6089 | { | |
a616058b | 6090 | int cpu, i; |
51888ca2 SV |
6091 | |
6092 | for_each_cpu_mask(cpu, *cpu_map) { | |
51888ca2 SV |
6093 | struct sched_group **sched_group_nodes |
6094 | = sched_group_nodes_bycpu[cpu]; | |
6095 | ||
51888ca2 SV |
6096 | if (!sched_group_nodes) |
6097 | continue; | |
6098 | ||
6099 | for (i = 0; i < MAX_NUMNODES; i++) { | |
6100 | cpumask_t nodemask = node_to_cpumask(i); | |
6101 | struct sched_group *oldsg, *sg = sched_group_nodes[i]; | |
6102 | ||
6103 | cpus_and(nodemask, nodemask, *cpu_map); | |
6104 | if (cpus_empty(nodemask)) | |
6105 | continue; | |
6106 | ||
6107 | if (sg == NULL) | |
6108 | continue; | |
6109 | sg = sg->next; | |
6110 | next_sg: | |
6111 | oldsg = sg; | |
6112 | sg = sg->next; | |
6113 | kfree(oldsg); | |
6114 | if (oldsg != sched_group_nodes[i]) | |
6115 | goto next_sg; | |
6116 | } | |
6117 | kfree(sched_group_nodes); | |
6118 | sched_group_nodes_bycpu[cpu] = NULL; | |
6119 | } | |
51888ca2 | 6120 | } |
a616058b SS |
6121 | #else |
6122 | static void free_sched_groups(const cpumask_t *cpu_map) | |
6123 | { | |
6124 | } | |
6125 | #endif | |
51888ca2 | 6126 | |
89c4710e SS |
6127 | /* |
6128 | * Initialize sched groups cpu_power. | |
6129 | * | |
6130 | * cpu_power indicates the capacity of sched group, which is used while | |
6131 | * distributing the load between different sched groups in a sched domain. | |
6132 | * Typically cpu_power for all the groups in a sched domain will be same unless | |
6133 | * there are asymmetries in the topology. If there are asymmetries, group | |
6134 | * having more cpu_power will pickup more load compared to the group having | |
6135 | * less cpu_power. | |
6136 | * | |
6137 | * cpu_power will be a multiple of SCHED_LOAD_SCALE. This multiple represents | |
6138 | * the maximum number of tasks a group can handle in the presence of other idle | |
6139 | * or lightly loaded groups in the same sched domain. | |
6140 | */ | |
6141 | static void init_sched_groups_power(int cpu, struct sched_domain *sd) | |
6142 | { | |
6143 | struct sched_domain *child; | |
6144 | struct sched_group *group; | |
6145 | ||
6146 | WARN_ON(!sd || !sd->groups); | |
6147 | ||
6148 | if (cpu != first_cpu(sd->groups->cpumask)) | |
6149 | return; | |
6150 | ||
6151 | child = sd->child; | |
6152 | ||
5517d86b ED |
6153 | sd->groups->__cpu_power = 0; |
6154 | ||
89c4710e SS |
6155 | /* |
6156 | * For perf policy, if the groups in child domain share resources | |
6157 | * (for example cores sharing some portions of the cache hierarchy | |
6158 | * or SMT), then set this domain groups cpu_power such that each group | |
6159 | * can handle only one task, when there are other idle groups in the | |
6160 | * same sched domain. | |
6161 | */ | |
6162 | if (!child || (!(sd->flags & SD_POWERSAVINGS_BALANCE) && | |
6163 | (child->flags & | |
6164 | (SD_SHARE_CPUPOWER | SD_SHARE_PKG_RESOURCES)))) { | |
5517d86b | 6165 | sg_inc_cpu_power(sd->groups, SCHED_LOAD_SCALE); |
89c4710e SS |
6166 | return; |
6167 | } | |
6168 | ||
89c4710e SS |
6169 | /* |
6170 | * add cpu_power of each child group to this groups cpu_power | |
6171 | */ | |
6172 | group = child->groups; | |
6173 | do { | |
5517d86b | 6174 | sg_inc_cpu_power(sd->groups, group->__cpu_power); |
89c4710e SS |
6175 | group = group->next; |
6176 | } while (group != child->groups); | |
6177 | } | |
6178 | ||
1da177e4 | 6179 | /* |
1a20ff27 DG |
6180 | * Build sched domains for a given set of cpus and attach the sched domains |
6181 | * to the individual cpus | |
1da177e4 | 6182 | */ |
51888ca2 | 6183 | static int build_sched_domains(const cpumask_t *cpu_map) |
1da177e4 LT |
6184 | { |
6185 | int i; | |
d1b55138 JH |
6186 | #ifdef CONFIG_NUMA |
6187 | struct sched_group **sched_group_nodes = NULL; | |
6711cab4 | 6188 | int sd_allnodes = 0; |
d1b55138 JH |
6189 | |
6190 | /* | |
6191 | * Allocate the per-node list of sched groups | |
6192 | */ | |
5cf9f062 | 6193 | sched_group_nodes = kcalloc(MAX_NUMNODES, sizeof(struct sched_group *), |
41a2d6cf | 6194 | GFP_KERNEL); |
d1b55138 JH |
6195 | if (!sched_group_nodes) { |
6196 | printk(KERN_WARNING "Can not alloc sched group node list\n"); | |
51888ca2 | 6197 | return -ENOMEM; |
d1b55138 JH |
6198 | } |
6199 | sched_group_nodes_bycpu[first_cpu(*cpu_map)] = sched_group_nodes; | |
6200 | #endif | |
1da177e4 LT |
6201 | |
6202 | /* | |
1a20ff27 | 6203 | * Set up domains for cpus specified by the cpu_map. |
1da177e4 | 6204 | */ |
1a20ff27 | 6205 | for_each_cpu_mask(i, *cpu_map) { |
1da177e4 LT |
6206 | struct sched_domain *sd = NULL, *p; |
6207 | cpumask_t nodemask = node_to_cpumask(cpu_to_node(i)); | |
6208 | ||
1a20ff27 | 6209 | cpus_and(nodemask, nodemask, *cpu_map); |
1da177e4 LT |
6210 | |
6211 | #ifdef CONFIG_NUMA | |
dd41f596 IM |
6212 | if (cpus_weight(*cpu_map) > |
6213 | SD_NODES_PER_DOMAIN*cpus_weight(nodemask)) { | |
9c1cfda2 JH |
6214 | sd = &per_cpu(allnodes_domains, i); |
6215 | *sd = SD_ALLNODES_INIT; | |
6216 | sd->span = *cpu_map; | |
6711cab4 | 6217 | cpu_to_allnodes_group(i, cpu_map, &sd->groups); |
9c1cfda2 | 6218 | p = sd; |
6711cab4 | 6219 | sd_allnodes = 1; |
9c1cfda2 JH |
6220 | } else |
6221 | p = NULL; | |
6222 | ||
1da177e4 | 6223 | sd = &per_cpu(node_domains, i); |
1da177e4 | 6224 | *sd = SD_NODE_INIT; |
9c1cfda2 JH |
6225 | sd->span = sched_domain_node_span(cpu_to_node(i)); |
6226 | sd->parent = p; | |
1a848870 SS |
6227 | if (p) |
6228 | p->child = sd; | |
9c1cfda2 | 6229 | cpus_and(sd->span, sd->span, *cpu_map); |
1da177e4 LT |
6230 | #endif |
6231 | ||
6232 | p = sd; | |
6233 | sd = &per_cpu(phys_domains, i); | |
1da177e4 LT |
6234 | *sd = SD_CPU_INIT; |
6235 | sd->span = nodemask; | |
6236 | sd->parent = p; | |
1a848870 SS |
6237 | if (p) |
6238 | p->child = sd; | |
6711cab4 | 6239 | cpu_to_phys_group(i, cpu_map, &sd->groups); |
1da177e4 | 6240 | |
1e9f28fa SS |
6241 | #ifdef CONFIG_SCHED_MC |
6242 | p = sd; | |
6243 | sd = &per_cpu(core_domains, i); | |
1e9f28fa SS |
6244 | *sd = SD_MC_INIT; |
6245 | sd->span = cpu_coregroup_map(i); | |
6246 | cpus_and(sd->span, sd->span, *cpu_map); | |
6247 | sd->parent = p; | |
1a848870 | 6248 | p->child = sd; |
6711cab4 | 6249 | cpu_to_core_group(i, cpu_map, &sd->groups); |
1e9f28fa SS |
6250 | #endif |
6251 | ||
1da177e4 LT |
6252 | #ifdef CONFIG_SCHED_SMT |
6253 | p = sd; | |
6254 | sd = &per_cpu(cpu_domains, i); | |
1da177e4 | 6255 | *sd = SD_SIBLING_INIT; |
d5a7430d | 6256 | sd->span = per_cpu(cpu_sibling_map, i); |
1a20ff27 | 6257 | cpus_and(sd->span, sd->span, *cpu_map); |
1da177e4 | 6258 | sd->parent = p; |
1a848870 | 6259 | p->child = sd; |
6711cab4 | 6260 | cpu_to_cpu_group(i, cpu_map, &sd->groups); |
1da177e4 LT |
6261 | #endif |
6262 | } | |
6263 | ||
6264 | #ifdef CONFIG_SCHED_SMT | |
6265 | /* Set up CPU (sibling) groups */ | |
9c1cfda2 | 6266 | for_each_cpu_mask(i, *cpu_map) { |
d5a7430d | 6267 | cpumask_t this_sibling_map = per_cpu(cpu_sibling_map, i); |
1a20ff27 | 6268 | cpus_and(this_sibling_map, this_sibling_map, *cpu_map); |
1da177e4 LT |
6269 | if (i != first_cpu(this_sibling_map)) |
6270 | continue; | |
6271 | ||
dd41f596 IM |
6272 | init_sched_build_groups(this_sibling_map, cpu_map, |
6273 | &cpu_to_cpu_group); | |
1da177e4 LT |
6274 | } |
6275 | #endif | |
6276 | ||
1e9f28fa SS |
6277 | #ifdef CONFIG_SCHED_MC |
6278 | /* Set up multi-core groups */ | |
6279 | for_each_cpu_mask(i, *cpu_map) { | |
6280 | cpumask_t this_core_map = cpu_coregroup_map(i); | |
6281 | cpus_and(this_core_map, this_core_map, *cpu_map); | |
6282 | if (i != first_cpu(this_core_map)) | |
6283 | continue; | |
dd41f596 IM |
6284 | init_sched_build_groups(this_core_map, cpu_map, |
6285 | &cpu_to_core_group); | |
1e9f28fa SS |
6286 | } |
6287 | #endif | |
6288 | ||
1da177e4 LT |
6289 | /* Set up physical groups */ |
6290 | for (i = 0; i < MAX_NUMNODES; i++) { | |
6291 | cpumask_t nodemask = node_to_cpumask(i); | |
6292 | ||
1a20ff27 | 6293 | cpus_and(nodemask, nodemask, *cpu_map); |
1da177e4 LT |
6294 | if (cpus_empty(nodemask)) |
6295 | continue; | |
6296 | ||
6711cab4 | 6297 | init_sched_build_groups(nodemask, cpu_map, &cpu_to_phys_group); |
1da177e4 LT |
6298 | } |
6299 | ||
6300 | #ifdef CONFIG_NUMA | |
6301 | /* Set up node groups */ | |
6711cab4 | 6302 | if (sd_allnodes) |
dd41f596 IM |
6303 | init_sched_build_groups(*cpu_map, cpu_map, |
6304 | &cpu_to_allnodes_group); | |
9c1cfda2 JH |
6305 | |
6306 | for (i = 0; i < MAX_NUMNODES; i++) { | |
6307 | /* Set up node groups */ | |
6308 | struct sched_group *sg, *prev; | |
6309 | cpumask_t nodemask = node_to_cpumask(i); | |
6310 | cpumask_t domainspan; | |
6311 | cpumask_t covered = CPU_MASK_NONE; | |
6312 | int j; | |
6313 | ||
6314 | cpus_and(nodemask, nodemask, *cpu_map); | |
d1b55138 JH |
6315 | if (cpus_empty(nodemask)) { |
6316 | sched_group_nodes[i] = NULL; | |
9c1cfda2 | 6317 | continue; |
d1b55138 | 6318 | } |
9c1cfda2 JH |
6319 | |
6320 | domainspan = sched_domain_node_span(i); | |
6321 | cpus_and(domainspan, domainspan, *cpu_map); | |
6322 | ||
15f0b676 | 6323 | sg = kmalloc_node(sizeof(struct sched_group), GFP_KERNEL, i); |
51888ca2 SV |
6324 | if (!sg) { |
6325 | printk(KERN_WARNING "Can not alloc domain group for " | |
6326 | "node %d\n", i); | |
6327 | goto error; | |
6328 | } | |
9c1cfda2 JH |
6329 | sched_group_nodes[i] = sg; |
6330 | for_each_cpu_mask(j, nodemask) { | |
6331 | struct sched_domain *sd; | |
9761eea8 | 6332 | |
9c1cfda2 JH |
6333 | sd = &per_cpu(node_domains, j); |
6334 | sd->groups = sg; | |
9c1cfda2 | 6335 | } |
5517d86b | 6336 | sg->__cpu_power = 0; |
9c1cfda2 | 6337 | sg->cpumask = nodemask; |
51888ca2 | 6338 | sg->next = sg; |
9c1cfda2 JH |
6339 | cpus_or(covered, covered, nodemask); |
6340 | prev = sg; | |
6341 | ||
6342 | for (j = 0; j < MAX_NUMNODES; j++) { | |
6343 | cpumask_t tmp, notcovered; | |
6344 | int n = (i + j) % MAX_NUMNODES; | |
6345 | ||
6346 | cpus_complement(notcovered, covered); | |
6347 | cpus_and(tmp, notcovered, *cpu_map); | |
6348 | cpus_and(tmp, tmp, domainspan); | |
6349 | if (cpus_empty(tmp)) | |
6350 | break; | |
6351 | ||
6352 | nodemask = node_to_cpumask(n); | |
6353 | cpus_and(tmp, tmp, nodemask); | |
6354 | if (cpus_empty(tmp)) | |
6355 | continue; | |
6356 | ||
15f0b676 SV |
6357 | sg = kmalloc_node(sizeof(struct sched_group), |
6358 | GFP_KERNEL, i); | |
9c1cfda2 JH |
6359 | if (!sg) { |
6360 | printk(KERN_WARNING | |
6361 | "Can not alloc domain group for node %d\n", j); | |
51888ca2 | 6362 | goto error; |
9c1cfda2 | 6363 | } |
5517d86b | 6364 | sg->__cpu_power = 0; |
9c1cfda2 | 6365 | sg->cpumask = tmp; |
51888ca2 | 6366 | sg->next = prev->next; |
9c1cfda2 JH |
6367 | cpus_or(covered, covered, tmp); |
6368 | prev->next = sg; | |
6369 | prev = sg; | |
6370 | } | |
9c1cfda2 | 6371 | } |
1da177e4 LT |
6372 | #endif |
6373 | ||
6374 | /* Calculate CPU power for physical packages and nodes */ | |
5c45bf27 | 6375 | #ifdef CONFIG_SCHED_SMT |
1a20ff27 | 6376 | for_each_cpu_mask(i, *cpu_map) { |
dd41f596 IM |
6377 | struct sched_domain *sd = &per_cpu(cpu_domains, i); |
6378 | ||
89c4710e | 6379 | init_sched_groups_power(i, sd); |
5c45bf27 | 6380 | } |
1da177e4 | 6381 | #endif |
1e9f28fa | 6382 | #ifdef CONFIG_SCHED_MC |
5c45bf27 | 6383 | for_each_cpu_mask(i, *cpu_map) { |
dd41f596 IM |
6384 | struct sched_domain *sd = &per_cpu(core_domains, i); |
6385 | ||
89c4710e | 6386 | init_sched_groups_power(i, sd); |
5c45bf27 SS |
6387 | } |
6388 | #endif | |
1e9f28fa | 6389 | |
5c45bf27 | 6390 | for_each_cpu_mask(i, *cpu_map) { |
dd41f596 IM |
6391 | struct sched_domain *sd = &per_cpu(phys_domains, i); |
6392 | ||
89c4710e | 6393 | init_sched_groups_power(i, sd); |
1da177e4 LT |
6394 | } |
6395 | ||
9c1cfda2 | 6396 | #ifdef CONFIG_NUMA |
08069033 SS |
6397 | for (i = 0; i < MAX_NUMNODES; i++) |
6398 | init_numa_sched_groups_power(sched_group_nodes[i]); | |
9c1cfda2 | 6399 | |
6711cab4 SS |
6400 | if (sd_allnodes) { |
6401 | struct sched_group *sg; | |
f712c0c7 | 6402 | |
6711cab4 | 6403 | cpu_to_allnodes_group(first_cpu(*cpu_map), cpu_map, &sg); |
f712c0c7 SS |
6404 | init_numa_sched_groups_power(sg); |
6405 | } | |
9c1cfda2 JH |
6406 | #endif |
6407 | ||
1da177e4 | 6408 | /* Attach the domains */ |
1a20ff27 | 6409 | for_each_cpu_mask(i, *cpu_map) { |
1da177e4 LT |
6410 | struct sched_domain *sd; |
6411 | #ifdef CONFIG_SCHED_SMT | |
6412 | sd = &per_cpu(cpu_domains, i); | |
1e9f28fa SS |
6413 | #elif defined(CONFIG_SCHED_MC) |
6414 | sd = &per_cpu(core_domains, i); | |
1da177e4 LT |
6415 | #else |
6416 | sd = &per_cpu(phys_domains, i); | |
6417 | #endif | |
6418 | cpu_attach_domain(sd, i); | |
6419 | } | |
51888ca2 SV |
6420 | |
6421 | return 0; | |
6422 | ||
a616058b | 6423 | #ifdef CONFIG_NUMA |
51888ca2 SV |
6424 | error: |
6425 | free_sched_groups(cpu_map); | |
6426 | return -ENOMEM; | |
a616058b | 6427 | #endif |
1da177e4 | 6428 | } |
029190c5 PJ |
6429 | |
6430 | static cpumask_t *doms_cur; /* current sched domains */ | |
6431 | static int ndoms_cur; /* number of sched domains in 'doms_cur' */ | |
6432 | ||
6433 | /* | |
6434 | * Special case: If a kmalloc of a doms_cur partition (array of | |
6435 | * cpumask_t) fails, then fallback to a single sched domain, | |
6436 | * as determined by the single cpumask_t fallback_doms. | |
6437 | */ | |
6438 | static cpumask_t fallback_doms; | |
6439 | ||
1a20ff27 | 6440 | /* |
41a2d6cf | 6441 | * Set up scheduler domains and groups. Callers must hold the hotplug lock. |
029190c5 PJ |
6442 | * For now this just excludes isolated cpus, but could be used to |
6443 | * exclude other special cases in the future. | |
1a20ff27 | 6444 | */ |
51888ca2 | 6445 | static int arch_init_sched_domains(const cpumask_t *cpu_map) |
1a20ff27 | 6446 | { |
7378547f MM |
6447 | int err; |
6448 | ||
029190c5 PJ |
6449 | ndoms_cur = 1; |
6450 | doms_cur = kmalloc(sizeof(cpumask_t), GFP_KERNEL); | |
6451 | if (!doms_cur) | |
6452 | doms_cur = &fallback_doms; | |
6453 | cpus_andnot(*doms_cur, *cpu_map, cpu_isolated_map); | |
7378547f | 6454 | err = build_sched_domains(doms_cur); |
6382bc90 | 6455 | register_sched_domain_sysctl(); |
7378547f MM |
6456 | |
6457 | return err; | |
1a20ff27 DG |
6458 | } |
6459 | ||
6460 | static void arch_destroy_sched_domains(const cpumask_t *cpu_map) | |
1da177e4 | 6461 | { |
51888ca2 | 6462 | free_sched_groups(cpu_map); |
9c1cfda2 | 6463 | } |
1da177e4 | 6464 | |
1a20ff27 DG |
6465 | /* |
6466 | * Detach sched domains from a group of cpus specified in cpu_map | |
6467 | * These cpus will now be attached to the NULL domain | |
6468 | */ | |
858119e1 | 6469 | static void detach_destroy_domains(const cpumask_t *cpu_map) |
1a20ff27 DG |
6470 | { |
6471 | int i; | |
6472 | ||
6382bc90 MM |
6473 | unregister_sched_domain_sysctl(); |
6474 | ||
1a20ff27 DG |
6475 | for_each_cpu_mask(i, *cpu_map) |
6476 | cpu_attach_domain(NULL, i); | |
6477 | synchronize_sched(); | |
6478 | arch_destroy_sched_domains(cpu_map); | |
6479 | } | |
6480 | ||
029190c5 PJ |
6481 | /* |
6482 | * Partition sched domains as specified by the 'ndoms_new' | |
41a2d6cf | 6483 | * cpumasks in the array doms_new[] of cpumasks. This compares |
029190c5 PJ |
6484 | * doms_new[] to the current sched domain partitioning, doms_cur[]. |
6485 | * It destroys each deleted domain and builds each new domain. | |
6486 | * | |
6487 | * 'doms_new' is an array of cpumask_t's of length 'ndoms_new'. | |
41a2d6cf IM |
6488 | * The masks don't intersect (don't overlap.) We should setup one |
6489 | * sched domain for each mask. CPUs not in any of the cpumasks will | |
6490 | * not be load balanced. If the same cpumask appears both in the | |
029190c5 PJ |
6491 | * current 'doms_cur' domains and in the new 'doms_new', we can leave |
6492 | * it as it is. | |
6493 | * | |
41a2d6cf IM |
6494 | * The passed in 'doms_new' should be kmalloc'd. This routine takes |
6495 | * ownership of it and will kfree it when done with it. If the caller | |
029190c5 PJ |
6496 | * failed the kmalloc call, then it can pass in doms_new == NULL, |
6497 | * and partition_sched_domains() will fallback to the single partition | |
6498 | * 'fallback_doms'. | |
6499 | * | |
6500 | * Call with hotplug lock held | |
6501 | */ | |
6502 | void partition_sched_domains(int ndoms_new, cpumask_t *doms_new) | |
6503 | { | |
6504 | int i, j; | |
6505 | ||
a1835615 SV |
6506 | lock_doms_cur(); |
6507 | ||
7378547f MM |
6508 | /* always unregister in case we don't destroy any domains */ |
6509 | unregister_sched_domain_sysctl(); | |
6510 | ||
029190c5 PJ |
6511 | if (doms_new == NULL) { |
6512 | ndoms_new = 1; | |
6513 | doms_new = &fallback_doms; | |
6514 | cpus_andnot(doms_new[0], cpu_online_map, cpu_isolated_map); | |
6515 | } | |
6516 | ||
6517 | /* Destroy deleted domains */ | |
6518 | for (i = 0; i < ndoms_cur; i++) { | |
6519 | for (j = 0; j < ndoms_new; j++) { | |
6520 | if (cpus_equal(doms_cur[i], doms_new[j])) | |
6521 | goto match1; | |
6522 | } | |
6523 | /* no match - a current sched domain not in new doms_new[] */ | |
6524 | detach_destroy_domains(doms_cur + i); | |
6525 | match1: | |
6526 | ; | |
6527 | } | |
6528 | ||
6529 | /* Build new domains */ | |
6530 | for (i = 0; i < ndoms_new; i++) { | |
6531 | for (j = 0; j < ndoms_cur; j++) { | |
6532 | if (cpus_equal(doms_new[i], doms_cur[j])) | |
6533 | goto match2; | |
6534 | } | |
6535 | /* no match - add a new doms_new */ | |
6536 | build_sched_domains(doms_new + i); | |
6537 | match2: | |
6538 | ; | |
6539 | } | |
6540 | ||
6541 | /* Remember the new sched domains */ | |
6542 | if (doms_cur != &fallback_doms) | |
6543 | kfree(doms_cur); | |
6544 | doms_cur = doms_new; | |
6545 | ndoms_cur = ndoms_new; | |
7378547f MM |
6546 | |
6547 | register_sched_domain_sysctl(); | |
a1835615 SV |
6548 | |
6549 | unlock_doms_cur(); | |
029190c5 PJ |
6550 | } |
6551 | ||
5c45bf27 | 6552 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) |
6707de00 | 6553 | static int arch_reinit_sched_domains(void) |
5c45bf27 SS |
6554 | { |
6555 | int err; | |
6556 | ||
95402b38 | 6557 | get_online_cpus(); |
5c45bf27 SS |
6558 | detach_destroy_domains(&cpu_online_map); |
6559 | err = arch_init_sched_domains(&cpu_online_map); | |
95402b38 | 6560 | put_online_cpus(); |
5c45bf27 SS |
6561 | |
6562 | return err; | |
6563 | } | |
6564 | ||
6565 | static ssize_t sched_power_savings_store(const char *buf, size_t count, int smt) | |
6566 | { | |
6567 | int ret; | |
6568 | ||
6569 | if (buf[0] != '0' && buf[0] != '1') | |
6570 | return -EINVAL; | |
6571 | ||
6572 | if (smt) | |
6573 | sched_smt_power_savings = (buf[0] == '1'); | |
6574 | else | |
6575 | sched_mc_power_savings = (buf[0] == '1'); | |
6576 | ||
6577 | ret = arch_reinit_sched_domains(); | |
6578 | ||
6579 | return ret ? ret : count; | |
6580 | } | |
6581 | ||
5c45bf27 SS |
6582 | #ifdef CONFIG_SCHED_MC |
6583 | static ssize_t sched_mc_power_savings_show(struct sys_device *dev, char *page) | |
6584 | { | |
6585 | return sprintf(page, "%u\n", sched_mc_power_savings); | |
6586 | } | |
48f24c4d IM |
6587 | static ssize_t sched_mc_power_savings_store(struct sys_device *dev, |
6588 | const char *buf, size_t count) | |
5c45bf27 SS |
6589 | { |
6590 | return sched_power_savings_store(buf, count, 0); | |
6591 | } | |
6707de00 AB |
6592 | static SYSDEV_ATTR(sched_mc_power_savings, 0644, sched_mc_power_savings_show, |
6593 | sched_mc_power_savings_store); | |
5c45bf27 SS |
6594 | #endif |
6595 | ||
6596 | #ifdef CONFIG_SCHED_SMT | |
6597 | static ssize_t sched_smt_power_savings_show(struct sys_device *dev, char *page) | |
6598 | { | |
6599 | return sprintf(page, "%u\n", sched_smt_power_savings); | |
6600 | } | |
48f24c4d IM |
6601 | static ssize_t sched_smt_power_savings_store(struct sys_device *dev, |
6602 | const char *buf, size_t count) | |
5c45bf27 SS |
6603 | { |
6604 | return sched_power_savings_store(buf, count, 1); | |
6605 | } | |
6707de00 AB |
6606 | static SYSDEV_ATTR(sched_smt_power_savings, 0644, sched_smt_power_savings_show, |
6607 | sched_smt_power_savings_store); | |
6608 | #endif | |
6609 | ||
6610 | int sched_create_sysfs_power_savings_entries(struct sysdev_class *cls) | |
6611 | { | |
6612 | int err = 0; | |
6613 | ||
6614 | #ifdef CONFIG_SCHED_SMT | |
6615 | if (smt_capable()) | |
6616 | err = sysfs_create_file(&cls->kset.kobj, | |
6617 | &attr_sched_smt_power_savings.attr); | |
6618 | #endif | |
6619 | #ifdef CONFIG_SCHED_MC | |
6620 | if (!err && mc_capable()) | |
6621 | err = sysfs_create_file(&cls->kset.kobj, | |
6622 | &attr_sched_mc_power_savings.attr); | |
6623 | #endif | |
6624 | return err; | |
6625 | } | |
5c45bf27 SS |
6626 | #endif |
6627 | ||
1da177e4 | 6628 | /* |
41a2d6cf | 6629 | * Force a reinitialization of the sched domains hierarchy. The domains |
1da177e4 | 6630 | * and groups cannot be updated in place without racing with the balancing |
41c7ce9a | 6631 | * code, so we temporarily attach all running cpus to the NULL domain |
1da177e4 LT |
6632 | * which will prevent rebalancing while the sched domains are recalculated. |
6633 | */ | |
6634 | static int update_sched_domains(struct notifier_block *nfb, | |
6635 | unsigned long action, void *hcpu) | |
6636 | { | |
1da177e4 LT |
6637 | switch (action) { |
6638 | case CPU_UP_PREPARE: | |
8bb78442 | 6639 | case CPU_UP_PREPARE_FROZEN: |
1da177e4 | 6640 | case CPU_DOWN_PREPARE: |
8bb78442 | 6641 | case CPU_DOWN_PREPARE_FROZEN: |
1a20ff27 | 6642 | detach_destroy_domains(&cpu_online_map); |
1da177e4 LT |
6643 | return NOTIFY_OK; |
6644 | ||
6645 | case CPU_UP_CANCELED: | |
8bb78442 | 6646 | case CPU_UP_CANCELED_FROZEN: |
1da177e4 | 6647 | case CPU_DOWN_FAILED: |
8bb78442 | 6648 | case CPU_DOWN_FAILED_FROZEN: |
1da177e4 | 6649 | case CPU_ONLINE: |
8bb78442 | 6650 | case CPU_ONLINE_FROZEN: |
1da177e4 | 6651 | case CPU_DEAD: |
8bb78442 | 6652 | case CPU_DEAD_FROZEN: |
1da177e4 LT |
6653 | /* |
6654 | * Fall through and re-initialise the domains. | |
6655 | */ | |
6656 | break; | |
6657 | default: | |
6658 | return NOTIFY_DONE; | |
6659 | } | |
6660 | ||
6661 | /* The hotplug lock is already held by cpu_up/cpu_down */ | |
1a20ff27 | 6662 | arch_init_sched_domains(&cpu_online_map); |
1da177e4 LT |
6663 | |
6664 | return NOTIFY_OK; | |
6665 | } | |
1da177e4 LT |
6666 | |
6667 | void __init sched_init_smp(void) | |
6668 | { | |
5c1e1767 NP |
6669 | cpumask_t non_isolated_cpus; |
6670 | ||
95402b38 | 6671 | get_online_cpus(); |
1a20ff27 | 6672 | arch_init_sched_domains(&cpu_online_map); |
e5e5673f | 6673 | cpus_andnot(non_isolated_cpus, cpu_possible_map, cpu_isolated_map); |
5c1e1767 NP |
6674 | if (cpus_empty(non_isolated_cpus)) |
6675 | cpu_set(smp_processor_id(), non_isolated_cpus); | |
95402b38 | 6676 | put_online_cpus(); |
1da177e4 LT |
6677 | /* XXX: Theoretical race here - CPU may be hotplugged now */ |
6678 | hotcpu_notifier(update_sched_domains, 0); | |
5c1e1767 NP |
6679 | |
6680 | /* Move init over to a non-isolated CPU */ | |
6681 | if (set_cpus_allowed(current, non_isolated_cpus) < 0) | |
6682 | BUG(); | |
19978ca6 | 6683 | sched_init_granularity(); |
6b2d7700 SV |
6684 | |
6685 | #ifdef CONFIG_FAIR_GROUP_SCHED | |
6686 | if (nr_cpu_ids == 1) | |
6687 | return; | |
6688 | ||
6689 | lb_monitor_task = kthread_create(load_balance_monitor, NULL, | |
6690 | "group_balance"); | |
6691 | if (!IS_ERR(lb_monitor_task)) { | |
6692 | lb_monitor_task->flags |= PF_NOFREEZE; | |
6693 | wake_up_process(lb_monitor_task); | |
6694 | } else { | |
6695 | printk(KERN_ERR "Could not create load balance monitor thread" | |
6696 | "(error = %ld) \n", PTR_ERR(lb_monitor_task)); | |
6697 | } | |
6698 | #endif | |
1da177e4 LT |
6699 | } |
6700 | #else | |
6701 | void __init sched_init_smp(void) | |
6702 | { | |
19978ca6 | 6703 | sched_init_granularity(); |
1da177e4 LT |
6704 | } |
6705 | #endif /* CONFIG_SMP */ | |
6706 | ||
6707 | int in_sched_functions(unsigned long addr) | |
6708 | { | |
1da177e4 LT |
6709 | return in_lock_functions(addr) || |
6710 | (addr >= (unsigned long)__sched_text_start | |
6711 | && addr < (unsigned long)__sched_text_end); | |
6712 | } | |
6713 | ||
a9957449 | 6714 | static void init_cfs_rq(struct cfs_rq *cfs_rq, struct rq *rq) |
dd41f596 IM |
6715 | { |
6716 | cfs_rq->tasks_timeline = RB_ROOT; | |
dd41f596 IM |
6717 | #ifdef CONFIG_FAIR_GROUP_SCHED |
6718 | cfs_rq->rq = rq; | |
6719 | #endif | |
67e9fb2a | 6720 | cfs_rq->min_vruntime = (u64)(-(1LL << 20)); |
dd41f596 IM |
6721 | } |
6722 | ||
1da177e4 LT |
6723 | void __init sched_init(void) |
6724 | { | |
476f3534 | 6725 | int highest_cpu = 0; |
dd41f596 IM |
6726 | int i, j; |
6727 | ||
0a945022 | 6728 | for_each_possible_cpu(i) { |
dd41f596 | 6729 | struct rt_prio_array *array; |
70b97a7f | 6730 | struct rq *rq; |
1da177e4 LT |
6731 | |
6732 | rq = cpu_rq(i); | |
6733 | spin_lock_init(&rq->lock); | |
fcb99371 | 6734 | lockdep_set_class(&rq->lock, &rq->rq_lock_key); |
7897986b | 6735 | rq->nr_running = 0; |
dd41f596 IM |
6736 | rq->clock = 1; |
6737 | init_cfs_rq(&rq->cfs, rq); | |
6738 | #ifdef CONFIG_FAIR_GROUP_SCHED | |
6739 | INIT_LIST_HEAD(&rq->leaf_cfs_rq_list); | |
3a252015 IM |
6740 | { |
6741 | struct cfs_rq *cfs_rq = &per_cpu(init_cfs_rq, i); | |
6742 | struct sched_entity *se = | |
6743 | &per_cpu(init_sched_entity, i); | |
6744 | ||
6745 | init_cfs_rq_p[i] = cfs_rq; | |
6746 | init_cfs_rq(cfs_rq, rq); | |
4cf86d77 | 6747 | cfs_rq->tg = &init_task_group; |
3a252015 | 6748 | list_add(&cfs_rq->leaf_cfs_rq_list, |
29f59db3 SV |
6749 | &rq->leaf_cfs_rq_list); |
6750 | ||
3a252015 IM |
6751 | init_sched_entity_p[i] = se; |
6752 | se->cfs_rq = &rq->cfs; | |
6753 | se->my_q = cfs_rq; | |
4cf86d77 | 6754 | se->load.weight = init_task_group_load; |
9b5b7751 | 6755 | se->load.inv_weight = |
4cf86d77 | 6756 | div64_64(1ULL<<32, init_task_group_load); |
3a252015 IM |
6757 | se->parent = NULL; |
6758 | } | |
4cf86d77 | 6759 | init_task_group.shares = init_task_group_load; |
dd41f596 | 6760 | #endif |
1da177e4 | 6761 | |
dd41f596 IM |
6762 | for (j = 0; j < CPU_LOAD_IDX_MAX; j++) |
6763 | rq->cpu_load[j] = 0; | |
1da177e4 | 6764 | #ifdef CONFIG_SMP |
41c7ce9a | 6765 | rq->sd = NULL; |
1da177e4 | 6766 | rq->active_balance = 0; |
dd41f596 | 6767 | rq->next_balance = jiffies; |
1da177e4 | 6768 | rq->push_cpu = 0; |
0a2966b4 | 6769 | rq->cpu = i; |
1da177e4 LT |
6770 | rq->migration_thread = NULL; |
6771 | INIT_LIST_HEAD(&rq->migration_queue); | |
764a9d6f | 6772 | rq->rt.highest_prio = MAX_RT_PRIO; |
1da177e4 LT |
6773 | #endif |
6774 | atomic_set(&rq->nr_iowait, 0); | |
6775 | ||
dd41f596 IM |
6776 | array = &rq->rt.active; |
6777 | for (j = 0; j < MAX_RT_PRIO; j++) { | |
6778 | INIT_LIST_HEAD(array->queue + j); | |
6779 | __clear_bit(j, array->bitmap); | |
1da177e4 | 6780 | } |
476f3534 | 6781 | highest_cpu = i; |
dd41f596 IM |
6782 | /* delimiter for bitsearch: */ |
6783 | __set_bit(MAX_RT_PRIO, array->bitmap); | |
1da177e4 LT |
6784 | } |
6785 | ||
2dd73a4f | 6786 | set_load_weight(&init_task); |
b50f60ce | 6787 | |
e107be36 AK |
6788 | #ifdef CONFIG_PREEMPT_NOTIFIERS |
6789 | INIT_HLIST_HEAD(&init_task.preempt_notifiers); | |
6790 | #endif | |
6791 | ||
c9819f45 | 6792 | #ifdef CONFIG_SMP |
476f3534 | 6793 | nr_cpu_ids = highest_cpu + 1; |
c9819f45 CL |
6794 | open_softirq(SCHED_SOFTIRQ, run_rebalance_domains, NULL); |
6795 | #endif | |
6796 | ||
b50f60ce HC |
6797 | #ifdef CONFIG_RT_MUTEXES |
6798 | plist_head_init(&init_task.pi_waiters, &init_task.pi_lock); | |
6799 | #endif | |
6800 | ||
1da177e4 LT |
6801 | /* |
6802 | * The boot idle thread does lazy MMU switching as well: | |
6803 | */ | |
6804 | atomic_inc(&init_mm.mm_count); | |
6805 | enter_lazy_tlb(&init_mm, current); | |
6806 | ||
6807 | /* | |
6808 | * Make us the idle thread. Technically, schedule() should not be | |
6809 | * called from this thread, however somewhere below it might be, | |
6810 | * but because we are the idle thread, we just pick up running again | |
6811 | * when this runqueue becomes "idle". | |
6812 | */ | |
6813 | init_idle(current, smp_processor_id()); | |
dd41f596 IM |
6814 | /* |
6815 | * During early bootup we pretend to be a normal task: | |
6816 | */ | |
6817 | current->sched_class = &fair_sched_class; | |
1da177e4 LT |
6818 | } |
6819 | ||
6820 | #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP | |
6821 | void __might_sleep(char *file, int line) | |
6822 | { | |
48f24c4d | 6823 | #ifdef in_atomic |
1da177e4 LT |
6824 | static unsigned long prev_jiffy; /* ratelimiting */ |
6825 | ||
6826 | if ((in_atomic() || irqs_disabled()) && | |
6827 | system_state == SYSTEM_RUNNING && !oops_in_progress) { | |
6828 | if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy) | |
6829 | return; | |
6830 | prev_jiffy = jiffies; | |
91368d73 | 6831 | printk(KERN_ERR "BUG: sleeping function called from invalid" |
1da177e4 LT |
6832 | " context at %s:%d\n", file, line); |
6833 | printk("in_atomic():%d, irqs_disabled():%d\n", | |
6834 | in_atomic(), irqs_disabled()); | |
a4c410f0 | 6835 | debug_show_held_locks(current); |
3117df04 IM |
6836 | if (irqs_disabled()) |
6837 | print_irqtrace_events(current); | |
1da177e4 LT |
6838 | dump_stack(); |
6839 | } | |
6840 | #endif | |
6841 | } | |
6842 | EXPORT_SYMBOL(__might_sleep); | |
6843 | #endif | |
6844 | ||
6845 | #ifdef CONFIG_MAGIC_SYSRQ | |
3a5e4dc1 AK |
6846 | static void normalize_task(struct rq *rq, struct task_struct *p) |
6847 | { | |
6848 | int on_rq; | |
6849 | update_rq_clock(rq); | |
6850 | on_rq = p->se.on_rq; | |
6851 | if (on_rq) | |
6852 | deactivate_task(rq, p, 0); | |
6853 | __setscheduler(rq, p, SCHED_NORMAL, 0); | |
6854 | if (on_rq) { | |
6855 | activate_task(rq, p, 0); | |
6856 | resched_task(rq->curr); | |
6857 | } | |
6858 | } | |
6859 | ||
1da177e4 LT |
6860 | void normalize_rt_tasks(void) |
6861 | { | |
a0f98a1c | 6862 | struct task_struct *g, *p; |
1da177e4 | 6863 | unsigned long flags; |
70b97a7f | 6864 | struct rq *rq; |
1da177e4 LT |
6865 | |
6866 | read_lock_irq(&tasklist_lock); | |
a0f98a1c | 6867 | do_each_thread(g, p) { |
178be793 IM |
6868 | /* |
6869 | * Only normalize user tasks: | |
6870 | */ | |
6871 | if (!p->mm) | |
6872 | continue; | |
6873 | ||
6cfb0d5d | 6874 | p->se.exec_start = 0; |
6cfb0d5d | 6875 | #ifdef CONFIG_SCHEDSTATS |
dd41f596 | 6876 | p->se.wait_start = 0; |
dd41f596 | 6877 | p->se.sleep_start = 0; |
dd41f596 | 6878 | p->se.block_start = 0; |
6cfb0d5d | 6879 | #endif |
dd41f596 IM |
6880 | task_rq(p)->clock = 0; |
6881 | ||
6882 | if (!rt_task(p)) { | |
6883 | /* | |
6884 | * Renice negative nice level userspace | |
6885 | * tasks back to 0: | |
6886 | */ | |
6887 | if (TASK_NICE(p) < 0 && p->mm) | |
6888 | set_user_nice(p, 0); | |
1da177e4 | 6889 | continue; |
dd41f596 | 6890 | } |
1da177e4 | 6891 | |
b29739f9 IM |
6892 | spin_lock_irqsave(&p->pi_lock, flags); |
6893 | rq = __task_rq_lock(p); | |
1da177e4 | 6894 | |
178be793 | 6895 | normalize_task(rq, p); |
3a5e4dc1 | 6896 | |
b29739f9 IM |
6897 | __task_rq_unlock(rq); |
6898 | spin_unlock_irqrestore(&p->pi_lock, flags); | |
a0f98a1c IM |
6899 | } while_each_thread(g, p); |
6900 | ||
1da177e4 LT |
6901 | read_unlock_irq(&tasklist_lock); |
6902 | } | |
6903 | ||
6904 | #endif /* CONFIG_MAGIC_SYSRQ */ | |
1df5c10a LT |
6905 | |
6906 | #ifdef CONFIG_IA64 | |
6907 | /* | |
6908 | * These functions are only useful for the IA64 MCA handling. | |
6909 | * | |
6910 | * They can only be called when the whole system has been | |
6911 | * stopped - every CPU needs to be quiescent, and no scheduling | |
6912 | * activity can take place. Using them for anything else would | |
6913 | * be a serious bug, and as a result, they aren't even visible | |
6914 | * under any other configuration. | |
6915 | */ | |
6916 | ||
6917 | /** | |
6918 | * curr_task - return the current task for a given cpu. | |
6919 | * @cpu: the processor in question. | |
6920 | * | |
6921 | * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! | |
6922 | */ | |
36c8b586 | 6923 | struct task_struct *curr_task(int cpu) |
1df5c10a LT |
6924 | { |
6925 | return cpu_curr(cpu); | |
6926 | } | |
6927 | ||
6928 | /** | |
6929 | * set_curr_task - set the current task for a given cpu. | |
6930 | * @cpu: the processor in question. | |
6931 | * @p: the task pointer to set. | |
6932 | * | |
6933 | * Description: This function must only be used when non-maskable interrupts | |
41a2d6cf IM |
6934 | * are serviced on a separate stack. It allows the architecture to switch the |
6935 | * notion of the current task on a cpu in a non-blocking manner. This function | |
1df5c10a LT |
6936 | * must be called with all CPU's synchronized, and interrupts disabled, the |
6937 | * and caller must save the original value of the current task (see | |
6938 | * curr_task() above) and restore that value before reenabling interrupts and | |
6939 | * re-starting the system. | |
6940 | * | |
6941 | * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! | |
6942 | */ | |
36c8b586 | 6943 | void set_curr_task(int cpu, struct task_struct *p) |
1df5c10a LT |
6944 | { |
6945 | cpu_curr(cpu) = p; | |
6946 | } | |
6947 | ||
6948 | #endif | |
29f59db3 SV |
6949 | |
6950 | #ifdef CONFIG_FAIR_GROUP_SCHED | |
6951 | ||
6b2d7700 SV |
6952 | #ifdef CONFIG_SMP |
6953 | /* | |
6954 | * distribute shares of all task groups among their schedulable entities, | |
6955 | * to reflect load distrbution across cpus. | |
6956 | */ | |
6957 | static int rebalance_shares(struct sched_domain *sd, int this_cpu) | |
6958 | { | |
6959 | struct cfs_rq *cfs_rq; | |
6960 | struct rq *rq = cpu_rq(this_cpu); | |
6961 | cpumask_t sdspan = sd->span; | |
6962 | int balanced = 1; | |
6963 | ||
6964 | /* Walk thr' all the task groups that we have */ | |
6965 | for_each_leaf_cfs_rq(rq, cfs_rq) { | |
6966 | int i; | |
6967 | unsigned long total_load = 0, total_shares; | |
6968 | struct task_group *tg = cfs_rq->tg; | |
6969 | ||
6970 | /* Gather total task load of this group across cpus */ | |
6971 | for_each_cpu_mask(i, sdspan) | |
6972 | total_load += tg->cfs_rq[i]->load.weight; | |
6973 | ||
6974 | /* Nothing to do if this group has no load */ | |
6975 | if (!total_load) | |
6976 | continue; | |
6977 | ||
6978 | /* | |
6979 | * tg->shares represents the number of cpu shares the task group | |
6980 | * is eligible to hold on a single cpu. On N cpus, it is | |
6981 | * eligible to hold (N * tg->shares) number of cpu shares. | |
6982 | */ | |
6983 | total_shares = tg->shares * cpus_weight(sdspan); | |
6984 | ||
6985 | /* | |
6986 | * redistribute total_shares across cpus as per the task load | |
6987 | * distribution. | |
6988 | */ | |
6989 | for_each_cpu_mask(i, sdspan) { | |
6990 | unsigned long local_load, local_shares; | |
6991 | ||
6992 | local_load = tg->cfs_rq[i]->load.weight; | |
6993 | local_shares = (local_load * total_shares) / total_load; | |
6994 | if (!local_shares) | |
6995 | local_shares = MIN_GROUP_SHARES; | |
6996 | if (local_shares == tg->se[i]->load.weight) | |
6997 | continue; | |
6998 | ||
6999 | spin_lock_irq(&cpu_rq(i)->lock); | |
7000 | set_se_shares(tg->se[i], local_shares); | |
7001 | spin_unlock_irq(&cpu_rq(i)->lock); | |
7002 | balanced = 0; | |
7003 | } | |
7004 | } | |
7005 | ||
7006 | return balanced; | |
7007 | } | |
7008 | ||
7009 | /* | |
7010 | * How frequently should we rebalance_shares() across cpus? | |
7011 | * | |
7012 | * The more frequently we rebalance shares, the more accurate is the fairness | |
7013 | * of cpu bandwidth distribution between task groups. However higher frequency | |
7014 | * also implies increased scheduling overhead. | |
7015 | * | |
7016 | * sysctl_sched_min_bal_int_shares represents the minimum interval between | |
7017 | * consecutive calls to rebalance_shares() in the same sched domain. | |
7018 | * | |
7019 | * sysctl_sched_max_bal_int_shares represents the maximum interval between | |
7020 | * consecutive calls to rebalance_shares() in the same sched domain. | |
7021 | * | |
7022 | * These settings allows for the appropriate tradeoff between accuracy of | |
7023 | * fairness and the associated overhead. | |
7024 | * | |
7025 | */ | |
7026 | ||
7027 | /* default: 8ms, units: milliseconds */ | |
7028 | const_debug unsigned int sysctl_sched_min_bal_int_shares = 8; | |
7029 | ||
7030 | /* default: 128ms, units: milliseconds */ | |
7031 | const_debug unsigned int sysctl_sched_max_bal_int_shares = 128; | |
7032 | ||
7033 | /* kernel thread that runs rebalance_shares() periodically */ | |
7034 | static int load_balance_monitor(void *unused) | |
7035 | { | |
7036 | unsigned int timeout = sysctl_sched_min_bal_int_shares; | |
7037 | struct sched_param schedparm; | |
7038 | int ret; | |
7039 | ||
7040 | /* | |
7041 | * We don't want this thread's execution to be limited by the shares | |
7042 | * assigned to default group (init_task_group). Hence make it run | |
7043 | * as a SCHED_RR RT task at the lowest priority. | |
7044 | */ | |
7045 | schedparm.sched_priority = 1; | |
7046 | ret = sched_setscheduler(current, SCHED_RR, &schedparm); | |
7047 | if (ret) | |
7048 | printk(KERN_ERR "Couldn't set SCHED_RR policy for load balance" | |
7049 | " monitor thread (error = %d) \n", ret); | |
7050 | ||
7051 | while (!kthread_should_stop()) { | |
7052 | int i, cpu, balanced = 1; | |
7053 | ||
7054 | /* Prevent cpus going down or coming up */ | |
86ef5c9a | 7055 | get_online_cpus(); |
6b2d7700 SV |
7056 | /* lockout changes to doms_cur[] array */ |
7057 | lock_doms_cur(); | |
7058 | /* | |
7059 | * Enter a rcu read-side critical section to safely walk rq->sd | |
7060 | * chain on various cpus and to walk task group list | |
7061 | * (rq->leaf_cfs_rq_list) in rebalance_shares(). | |
7062 | */ | |
7063 | rcu_read_lock(); | |
7064 | ||
7065 | for (i = 0; i < ndoms_cur; i++) { | |
7066 | cpumask_t cpumap = doms_cur[i]; | |
7067 | struct sched_domain *sd = NULL, *sd_prev = NULL; | |
7068 | ||
7069 | cpu = first_cpu(cpumap); | |
7070 | ||
7071 | /* Find the highest domain at which to balance shares */ | |
7072 | for_each_domain(cpu, sd) { | |
7073 | if (!(sd->flags & SD_LOAD_BALANCE)) | |
7074 | continue; | |
7075 | sd_prev = sd; | |
7076 | } | |
7077 | ||
7078 | sd = sd_prev; | |
7079 | /* sd == NULL? No load balance reqd in this domain */ | |
7080 | if (!sd) | |
7081 | continue; | |
7082 | ||
7083 | balanced &= rebalance_shares(sd, cpu); | |
7084 | } | |
7085 | ||
7086 | rcu_read_unlock(); | |
7087 | ||
7088 | unlock_doms_cur(); | |
86ef5c9a | 7089 | put_online_cpus(); |
6b2d7700 SV |
7090 | |
7091 | if (!balanced) | |
7092 | timeout = sysctl_sched_min_bal_int_shares; | |
7093 | else if (timeout < sysctl_sched_max_bal_int_shares) | |
7094 | timeout *= 2; | |
7095 | ||
7096 | msleep_interruptible(timeout); | |
7097 | } | |
7098 | ||
7099 | return 0; | |
7100 | } | |
7101 | #endif /* CONFIG_SMP */ | |
7102 | ||
29f59db3 | 7103 | /* allocate runqueue etc for a new task group */ |
4cf86d77 | 7104 | struct task_group *sched_create_group(void) |
29f59db3 | 7105 | { |
4cf86d77 | 7106 | struct task_group *tg; |
29f59db3 SV |
7107 | struct cfs_rq *cfs_rq; |
7108 | struct sched_entity *se; | |
9b5b7751 | 7109 | struct rq *rq; |
29f59db3 SV |
7110 | int i; |
7111 | ||
29f59db3 SV |
7112 | tg = kzalloc(sizeof(*tg), GFP_KERNEL); |
7113 | if (!tg) | |
7114 | return ERR_PTR(-ENOMEM); | |
7115 | ||
9b5b7751 | 7116 | tg->cfs_rq = kzalloc(sizeof(cfs_rq) * NR_CPUS, GFP_KERNEL); |
29f59db3 SV |
7117 | if (!tg->cfs_rq) |
7118 | goto err; | |
9b5b7751 | 7119 | tg->se = kzalloc(sizeof(se) * NR_CPUS, GFP_KERNEL); |
29f59db3 SV |
7120 | if (!tg->se) |
7121 | goto err; | |
7122 | ||
7123 | for_each_possible_cpu(i) { | |
9b5b7751 | 7124 | rq = cpu_rq(i); |
29f59db3 SV |
7125 | |
7126 | cfs_rq = kmalloc_node(sizeof(struct cfs_rq), GFP_KERNEL, | |
7127 | cpu_to_node(i)); | |
7128 | if (!cfs_rq) | |
7129 | goto err; | |
7130 | ||
7131 | se = kmalloc_node(sizeof(struct sched_entity), GFP_KERNEL, | |
7132 | cpu_to_node(i)); | |
7133 | if (!se) | |
7134 | goto err; | |
7135 | ||
7136 | memset(cfs_rq, 0, sizeof(struct cfs_rq)); | |
7137 | memset(se, 0, sizeof(struct sched_entity)); | |
7138 | ||
7139 | tg->cfs_rq[i] = cfs_rq; | |
7140 | init_cfs_rq(cfs_rq, rq); | |
7141 | cfs_rq->tg = tg; | |
29f59db3 SV |
7142 | |
7143 | tg->se[i] = se; | |
7144 | se->cfs_rq = &rq->cfs; | |
7145 | se->my_q = cfs_rq; | |
7146 | se->load.weight = NICE_0_LOAD; | |
7147 | se->load.inv_weight = div64_64(1ULL<<32, NICE_0_LOAD); | |
7148 | se->parent = NULL; | |
7149 | } | |
7150 | ||
ec2c507f SV |
7151 | tg->shares = NICE_0_LOAD; |
7152 | ||
7153 | lock_task_group_list(); | |
9b5b7751 SV |
7154 | for_each_possible_cpu(i) { |
7155 | rq = cpu_rq(i); | |
7156 | cfs_rq = tg->cfs_rq[i]; | |
7157 | list_add_rcu(&cfs_rq->leaf_cfs_rq_list, &rq->leaf_cfs_rq_list); | |
7158 | } | |
ec2c507f | 7159 | unlock_task_group_list(); |
29f59db3 | 7160 | |
9b5b7751 | 7161 | return tg; |
29f59db3 SV |
7162 | |
7163 | err: | |
7164 | for_each_possible_cpu(i) { | |
a65914b3 | 7165 | if (tg->cfs_rq) |
29f59db3 | 7166 | kfree(tg->cfs_rq[i]); |
a65914b3 | 7167 | if (tg->se) |
29f59db3 SV |
7168 | kfree(tg->se[i]); |
7169 | } | |
a65914b3 IM |
7170 | kfree(tg->cfs_rq); |
7171 | kfree(tg->se); | |
7172 | kfree(tg); | |
29f59db3 SV |
7173 | |
7174 | return ERR_PTR(-ENOMEM); | |
7175 | } | |
7176 | ||
9b5b7751 SV |
7177 | /* rcu callback to free various structures associated with a task group */ |
7178 | static void free_sched_group(struct rcu_head *rhp) | |
29f59db3 | 7179 | { |
ae8393e5 SV |
7180 | struct task_group *tg = container_of(rhp, struct task_group, rcu); |
7181 | struct cfs_rq *cfs_rq; | |
29f59db3 SV |
7182 | struct sched_entity *se; |
7183 | int i; | |
7184 | ||
29f59db3 SV |
7185 | /* now it should be safe to free those cfs_rqs */ |
7186 | for_each_possible_cpu(i) { | |
7187 | cfs_rq = tg->cfs_rq[i]; | |
7188 | kfree(cfs_rq); | |
7189 | ||
7190 | se = tg->se[i]; | |
7191 | kfree(se); | |
7192 | } | |
7193 | ||
7194 | kfree(tg->cfs_rq); | |
7195 | kfree(tg->se); | |
7196 | kfree(tg); | |
7197 | } | |
7198 | ||
9b5b7751 | 7199 | /* Destroy runqueue etc associated with a task group */ |
4cf86d77 | 7200 | void sched_destroy_group(struct task_group *tg) |
29f59db3 | 7201 | { |
7bae49d4 | 7202 | struct cfs_rq *cfs_rq = NULL; |
9b5b7751 | 7203 | int i; |
29f59db3 | 7204 | |
ec2c507f | 7205 | lock_task_group_list(); |
9b5b7751 SV |
7206 | for_each_possible_cpu(i) { |
7207 | cfs_rq = tg->cfs_rq[i]; | |
7208 | list_del_rcu(&cfs_rq->leaf_cfs_rq_list); | |
7209 | } | |
ec2c507f | 7210 | unlock_task_group_list(); |
9b5b7751 | 7211 | |
7bae49d4 | 7212 | BUG_ON(!cfs_rq); |
9b5b7751 SV |
7213 | |
7214 | /* wait for possible concurrent references to cfs_rqs complete */ | |
ae8393e5 | 7215 | call_rcu(&tg->rcu, free_sched_group); |
29f59db3 SV |
7216 | } |
7217 | ||
9b5b7751 | 7218 | /* change task's runqueue when it moves between groups. |
3a252015 IM |
7219 | * The caller of this function should have put the task in its new group |
7220 | * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to | |
7221 | * reflect its new group. | |
9b5b7751 SV |
7222 | */ |
7223 | void sched_move_task(struct task_struct *tsk) | |
29f59db3 SV |
7224 | { |
7225 | int on_rq, running; | |
7226 | unsigned long flags; | |
7227 | struct rq *rq; | |
7228 | ||
7229 | rq = task_rq_lock(tsk, &flags); | |
7230 | ||
dae51f56 | 7231 | if (tsk->sched_class != &fair_sched_class) { |
ce96b5ac | 7232 | set_task_cfs_rq(tsk, task_cpu(tsk)); |
29f59db3 | 7233 | goto done; |
dae51f56 | 7234 | } |
29f59db3 SV |
7235 | |
7236 | update_rq_clock(rq); | |
7237 | ||
051a1d1a | 7238 | running = task_current(rq, tsk); |
29f59db3 SV |
7239 | on_rq = tsk->se.on_rq; |
7240 | ||
83b699ed | 7241 | if (on_rq) { |
29f59db3 | 7242 | dequeue_task(rq, tsk, 0); |
83b699ed SV |
7243 | if (unlikely(running)) |
7244 | tsk->sched_class->put_prev_task(rq, tsk); | |
7245 | } | |
29f59db3 | 7246 | |
ce96b5ac | 7247 | set_task_cfs_rq(tsk, task_cpu(tsk)); |
29f59db3 | 7248 | |
83b699ed SV |
7249 | if (on_rq) { |
7250 | if (unlikely(running)) | |
7251 | tsk->sched_class->set_curr_task(rq); | |
7074badb | 7252 | enqueue_task(rq, tsk, 0); |
83b699ed | 7253 | } |
29f59db3 SV |
7254 | |
7255 | done: | |
7256 | task_rq_unlock(rq, &flags); | |
7257 | } | |
7258 | ||
6b2d7700 | 7259 | /* rq->lock to be locked by caller */ |
29f59db3 SV |
7260 | static void set_se_shares(struct sched_entity *se, unsigned long shares) |
7261 | { | |
7262 | struct cfs_rq *cfs_rq = se->cfs_rq; | |
7263 | struct rq *rq = cfs_rq->rq; | |
7264 | int on_rq; | |
7265 | ||
6b2d7700 SV |
7266 | if (!shares) |
7267 | shares = MIN_GROUP_SHARES; | |
29f59db3 SV |
7268 | |
7269 | on_rq = se->on_rq; | |
6b2d7700 | 7270 | if (on_rq) { |
29f59db3 | 7271 | dequeue_entity(cfs_rq, se, 0); |
6b2d7700 SV |
7272 | dec_cpu_load(rq, se->load.weight); |
7273 | } | |
29f59db3 SV |
7274 | |
7275 | se->load.weight = shares; | |
7276 | se->load.inv_weight = div64_64((1ULL<<32), shares); | |
7277 | ||
6b2d7700 | 7278 | if (on_rq) { |
29f59db3 | 7279 | enqueue_entity(cfs_rq, se, 0); |
6b2d7700 SV |
7280 | inc_cpu_load(rq, se->load.weight); |
7281 | } | |
29f59db3 SV |
7282 | } |
7283 | ||
4cf86d77 | 7284 | int sched_group_set_shares(struct task_group *tg, unsigned long shares) |
29f59db3 SV |
7285 | { |
7286 | int i; | |
6b2d7700 SV |
7287 | struct cfs_rq *cfs_rq; |
7288 | struct rq *rq; | |
c61935fd | 7289 | |
ec2c507f | 7290 | lock_task_group_list(); |
9b5b7751 | 7291 | if (tg->shares == shares) |
5cb350ba | 7292 | goto done; |
29f59db3 | 7293 | |
6b2d7700 SV |
7294 | if (shares < MIN_GROUP_SHARES) |
7295 | shares = MIN_GROUP_SHARES; | |
7296 | ||
7297 | /* | |
7298 | * Prevent any load balance activity (rebalance_shares, | |
7299 | * load_balance_fair) from referring to this group first, | |
7300 | * by taking it off the rq->leaf_cfs_rq_list on each cpu. | |
7301 | */ | |
7302 | for_each_possible_cpu(i) { | |
7303 | cfs_rq = tg->cfs_rq[i]; | |
7304 | list_del_rcu(&cfs_rq->leaf_cfs_rq_list); | |
7305 | } | |
7306 | ||
7307 | /* wait for any ongoing reference to this group to finish */ | |
7308 | synchronize_sched(); | |
7309 | ||
7310 | /* | |
7311 | * Now we are free to modify the group's share on each cpu | |
7312 | * w/o tripping rebalance_share or load_balance_fair. | |
7313 | */ | |
9b5b7751 | 7314 | tg->shares = shares; |
6b2d7700 SV |
7315 | for_each_possible_cpu(i) { |
7316 | spin_lock_irq(&cpu_rq(i)->lock); | |
9b5b7751 | 7317 | set_se_shares(tg->se[i], shares); |
6b2d7700 SV |
7318 | spin_unlock_irq(&cpu_rq(i)->lock); |
7319 | } | |
29f59db3 | 7320 | |
6b2d7700 SV |
7321 | /* |
7322 | * Enable load balance activity on this group, by inserting it back on | |
7323 | * each cpu's rq->leaf_cfs_rq_list. | |
7324 | */ | |
7325 | for_each_possible_cpu(i) { | |
7326 | rq = cpu_rq(i); | |
7327 | cfs_rq = tg->cfs_rq[i]; | |
7328 | list_add_rcu(&cfs_rq->leaf_cfs_rq_list, &rq->leaf_cfs_rq_list); | |
7329 | } | |
5cb350ba | 7330 | done: |
ec2c507f | 7331 | unlock_task_group_list(); |
9b5b7751 | 7332 | return 0; |
29f59db3 SV |
7333 | } |
7334 | ||
5cb350ba DG |
7335 | unsigned long sched_group_shares(struct task_group *tg) |
7336 | { | |
7337 | return tg->shares; | |
7338 | } | |
7339 | ||
3a252015 | 7340 | #endif /* CONFIG_FAIR_GROUP_SCHED */ |
68318b8e SV |
7341 | |
7342 | #ifdef CONFIG_FAIR_CGROUP_SCHED | |
7343 | ||
7344 | /* return corresponding task_group object of a cgroup */ | |
2b01dfe3 | 7345 | static inline struct task_group *cgroup_tg(struct cgroup *cgrp) |
68318b8e | 7346 | { |
2b01dfe3 PM |
7347 | return container_of(cgroup_subsys_state(cgrp, cpu_cgroup_subsys_id), |
7348 | struct task_group, css); | |
68318b8e SV |
7349 | } |
7350 | ||
7351 | static struct cgroup_subsys_state * | |
2b01dfe3 | 7352 | cpu_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cgrp) |
68318b8e SV |
7353 | { |
7354 | struct task_group *tg; | |
7355 | ||
2b01dfe3 | 7356 | if (!cgrp->parent) { |
68318b8e | 7357 | /* This is early initialization for the top cgroup */ |
2b01dfe3 | 7358 | init_task_group.css.cgroup = cgrp; |
68318b8e SV |
7359 | return &init_task_group.css; |
7360 | } | |
7361 | ||
7362 | /* we support only 1-level deep hierarchical scheduler atm */ | |
2b01dfe3 | 7363 | if (cgrp->parent->parent) |
68318b8e SV |
7364 | return ERR_PTR(-EINVAL); |
7365 | ||
7366 | tg = sched_create_group(); | |
7367 | if (IS_ERR(tg)) | |
7368 | return ERR_PTR(-ENOMEM); | |
7369 | ||
7370 | /* Bind the cgroup to task_group object we just created */ | |
2b01dfe3 | 7371 | tg->css.cgroup = cgrp; |
68318b8e SV |
7372 | |
7373 | return &tg->css; | |
7374 | } | |
7375 | ||
41a2d6cf IM |
7376 | static void |
7377 | cpu_cgroup_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp) | |
68318b8e | 7378 | { |
2b01dfe3 | 7379 | struct task_group *tg = cgroup_tg(cgrp); |
68318b8e SV |
7380 | |
7381 | sched_destroy_group(tg); | |
7382 | } | |
7383 | ||
41a2d6cf IM |
7384 | static int |
7385 | cpu_cgroup_can_attach(struct cgroup_subsys *ss, struct cgroup *cgrp, | |
7386 | struct task_struct *tsk) | |
68318b8e SV |
7387 | { |
7388 | /* We don't support RT-tasks being in separate groups */ | |
7389 | if (tsk->sched_class != &fair_sched_class) | |
7390 | return -EINVAL; | |
7391 | ||
7392 | return 0; | |
7393 | } | |
7394 | ||
7395 | static void | |
2b01dfe3 | 7396 | cpu_cgroup_attach(struct cgroup_subsys *ss, struct cgroup *cgrp, |
68318b8e SV |
7397 | struct cgroup *old_cont, struct task_struct *tsk) |
7398 | { | |
7399 | sched_move_task(tsk); | |
7400 | } | |
7401 | ||
2b01dfe3 PM |
7402 | static int cpu_shares_write_uint(struct cgroup *cgrp, struct cftype *cftype, |
7403 | u64 shareval) | |
68318b8e | 7404 | { |
2b01dfe3 | 7405 | return sched_group_set_shares(cgroup_tg(cgrp), shareval); |
68318b8e SV |
7406 | } |
7407 | ||
2b01dfe3 | 7408 | static u64 cpu_shares_read_uint(struct cgroup *cgrp, struct cftype *cft) |
68318b8e | 7409 | { |
2b01dfe3 | 7410 | struct task_group *tg = cgroup_tg(cgrp); |
68318b8e SV |
7411 | |
7412 | return (u64) tg->shares; | |
7413 | } | |
7414 | ||
fe5c7cc2 PM |
7415 | static struct cftype cpu_files[] = { |
7416 | { | |
7417 | .name = "shares", | |
7418 | .read_uint = cpu_shares_read_uint, | |
7419 | .write_uint = cpu_shares_write_uint, | |
7420 | }, | |
68318b8e SV |
7421 | }; |
7422 | ||
7423 | static int cpu_cgroup_populate(struct cgroup_subsys *ss, struct cgroup *cont) | |
7424 | { | |
fe5c7cc2 | 7425 | return cgroup_add_files(cont, ss, cpu_files, ARRAY_SIZE(cpu_files)); |
68318b8e SV |
7426 | } |
7427 | ||
7428 | struct cgroup_subsys cpu_cgroup_subsys = { | |
38605cae IM |
7429 | .name = "cpu", |
7430 | .create = cpu_cgroup_create, | |
7431 | .destroy = cpu_cgroup_destroy, | |
7432 | .can_attach = cpu_cgroup_can_attach, | |
7433 | .attach = cpu_cgroup_attach, | |
7434 | .populate = cpu_cgroup_populate, | |
7435 | .subsys_id = cpu_cgroup_subsys_id, | |
68318b8e SV |
7436 | .early_init = 1, |
7437 | }; | |
7438 | ||
7439 | #endif /* CONFIG_FAIR_CGROUP_SCHED */ | |
d842de87 SV |
7440 | |
7441 | #ifdef CONFIG_CGROUP_CPUACCT | |
7442 | ||
7443 | /* | |
7444 | * CPU accounting code for task groups. | |
7445 | * | |
7446 | * Based on the work by Paul Menage (menage@google.com) and Balbir Singh | |
7447 | * (balbir@in.ibm.com). | |
7448 | */ | |
7449 | ||
7450 | /* track cpu usage of a group of tasks */ | |
7451 | struct cpuacct { | |
7452 | struct cgroup_subsys_state css; | |
7453 | /* cpuusage holds pointer to a u64-type object on every cpu */ | |
7454 | u64 *cpuusage; | |
7455 | }; | |
7456 | ||
7457 | struct cgroup_subsys cpuacct_subsys; | |
7458 | ||
7459 | /* return cpu accounting group corresponding to this container */ | |
7460 | static inline struct cpuacct *cgroup_ca(struct cgroup *cont) | |
7461 | { | |
7462 | return container_of(cgroup_subsys_state(cont, cpuacct_subsys_id), | |
7463 | struct cpuacct, css); | |
7464 | } | |
7465 | ||
7466 | /* return cpu accounting group to which this task belongs */ | |
7467 | static inline struct cpuacct *task_ca(struct task_struct *tsk) | |
7468 | { | |
7469 | return container_of(task_subsys_state(tsk, cpuacct_subsys_id), | |
7470 | struct cpuacct, css); | |
7471 | } | |
7472 | ||
7473 | /* create a new cpu accounting group */ | |
7474 | static struct cgroup_subsys_state *cpuacct_create( | |
7475 | struct cgroup_subsys *ss, struct cgroup *cont) | |
7476 | { | |
7477 | struct cpuacct *ca = kzalloc(sizeof(*ca), GFP_KERNEL); | |
7478 | ||
7479 | if (!ca) | |
7480 | return ERR_PTR(-ENOMEM); | |
7481 | ||
7482 | ca->cpuusage = alloc_percpu(u64); | |
7483 | if (!ca->cpuusage) { | |
7484 | kfree(ca); | |
7485 | return ERR_PTR(-ENOMEM); | |
7486 | } | |
7487 | ||
7488 | return &ca->css; | |
7489 | } | |
7490 | ||
7491 | /* destroy an existing cpu accounting group */ | |
41a2d6cf IM |
7492 | static void |
7493 | cpuacct_destroy(struct cgroup_subsys *ss, struct cgroup *cont) | |
d842de87 SV |
7494 | { |
7495 | struct cpuacct *ca = cgroup_ca(cont); | |
7496 | ||
7497 | free_percpu(ca->cpuusage); | |
7498 | kfree(ca); | |
7499 | } | |
7500 | ||
7501 | /* return total cpu usage (in nanoseconds) of a group */ | |
7502 | static u64 cpuusage_read(struct cgroup *cont, struct cftype *cft) | |
7503 | { | |
7504 | struct cpuacct *ca = cgroup_ca(cont); | |
7505 | u64 totalcpuusage = 0; | |
7506 | int i; | |
7507 | ||
7508 | for_each_possible_cpu(i) { | |
7509 | u64 *cpuusage = percpu_ptr(ca->cpuusage, i); | |
7510 | ||
7511 | /* | |
7512 | * Take rq->lock to make 64-bit addition safe on 32-bit | |
7513 | * platforms. | |
7514 | */ | |
7515 | spin_lock_irq(&cpu_rq(i)->lock); | |
7516 | totalcpuusage += *cpuusage; | |
7517 | spin_unlock_irq(&cpu_rq(i)->lock); | |
7518 | } | |
7519 | ||
7520 | return totalcpuusage; | |
7521 | } | |
7522 | ||
7523 | static struct cftype files[] = { | |
7524 | { | |
7525 | .name = "usage", | |
7526 | .read_uint = cpuusage_read, | |
7527 | }, | |
7528 | }; | |
7529 | ||
7530 | static int cpuacct_populate(struct cgroup_subsys *ss, struct cgroup *cont) | |
7531 | { | |
7532 | return cgroup_add_files(cont, ss, files, ARRAY_SIZE(files)); | |
7533 | } | |
7534 | ||
7535 | /* | |
7536 | * charge this task's execution time to its accounting group. | |
7537 | * | |
7538 | * called with rq->lock held. | |
7539 | */ | |
7540 | static void cpuacct_charge(struct task_struct *tsk, u64 cputime) | |
7541 | { | |
7542 | struct cpuacct *ca; | |
7543 | ||
7544 | if (!cpuacct_subsys.active) | |
7545 | return; | |
7546 | ||
7547 | ca = task_ca(tsk); | |
7548 | if (ca) { | |
7549 | u64 *cpuusage = percpu_ptr(ca->cpuusage, task_cpu(tsk)); | |
7550 | ||
7551 | *cpuusage += cputime; | |
7552 | } | |
7553 | } | |
7554 | ||
7555 | struct cgroup_subsys cpuacct_subsys = { | |
7556 | .name = "cpuacct", | |
7557 | .create = cpuacct_create, | |
7558 | .destroy = cpuacct_destroy, | |
7559 | .populate = cpuacct_populate, | |
7560 | .subsys_id = cpuacct_subsys_id, | |
7561 | }; | |
7562 | #endif /* CONFIG_CGROUP_CPUACCT */ |