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; | |
a22d7fc1 | 349 | int overloaded; |
6aa645ea IM |
350 | }; |
351 | ||
57d885fe GH |
352 | #ifdef CONFIG_SMP |
353 | ||
354 | /* | |
355 | * We add the notion of a root-domain which will be used to define per-domain | |
356 | * variables. Each exclusive cpuset essentially defines an island domain by | |
357 | * fully partitioning the member cpus from any other cpuset. Whenever a new | |
358 | * exclusive cpuset is created, we also create and attach a new root-domain | |
359 | * object. | |
360 | * | |
361 | * By default the system creates a single root-domain with all cpus as | |
362 | * members (mimicking the global state we have today). | |
363 | */ | |
364 | struct root_domain { | |
365 | atomic_t refcount; | |
366 | cpumask_t span; | |
367 | cpumask_t online; | |
368 | }; | |
369 | ||
370 | static struct root_domain def_root_domain; | |
371 | ||
372 | #endif | |
373 | ||
1da177e4 LT |
374 | /* |
375 | * This is the main, per-CPU runqueue data structure. | |
376 | * | |
377 | * Locking rule: those places that want to lock multiple runqueues | |
378 | * (such as the load balancing or the thread migration code), lock | |
379 | * acquire operations must be ordered by ascending &runqueue. | |
380 | */ | |
70b97a7f | 381 | struct rq { |
d8016491 IM |
382 | /* runqueue lock: */ |
383 | spinlock_t lock; | |
1da177e4 LT |
384 | |
385 | /* | |
386 | * nr_running and cpu_load should be in the same cacheline because | |
387 | * remote CPUs use both these fields when doing load calculation. | |
388 | */ | |
389 | unsigned long nr_running; | |
6aa645ea IM |
390 | #define CPU_LOAD_IDX_MAX 5 |
391 | unsigned long cpu_load[CPU_LOAD_IDX_MAX]; | |
bdecea3a | 392 | unsigned char idle_at_tick; |
46cb4b7c SS |
393 | #ifdef CONFIG_NO_HZ |
394 | unsigned char in_nohz_recently; | |
395 | #endif | |
d8016491 IM |
396 | /* capture load from *all* tasks on this cpu: */ |
397 | struct load_weight load; | |
6aa645ea IM |
398 | unsigned long nr_load_updates; |
399 | u64 nr_switches; | |
400 | ||
401 | struct cfs_rq cfs; | |
402 | #ifdef CONFIG_FAIR_GROUP_SCHED | |
d8016491 IM |
403 | /* list of leaf cfs_rq on this cpu: */ |
404 | struct list_head leaf_cfs_rq_list; | |
1da177e4 | 405 | #endif |
41a2d6cf | 406 | struct rt_rq rt; |
1da177e4 LT |
407 | |
408 | /* | |
409 | * This is part of a global counter where only the total sum | |
410 | * over all CPUs matters. A task can increase this counter on | |
411 | * one CPU and if it got migrated afterwards it may decrease | |
412 | * it on another CPU. Always updated under the runqueue lock: | |
413 | */ | |
414 | unsigned long nr_uninterruptible; | |
415 | ||
36c8b586 | 416 | struct task_struct *curr, *idle; |
c9819f45 | 417 | unsigned long next_balance; |
1da177e4 | 418 | struct mm_struct *prev_mm; |
6aa645ea | 419 | |
6aa645ea IM |
420 | u64 clock, prev_clock_raw; |
421 | s64 clock_max_delta; | |
422 | ||
423 | unsigned int clock_warps, clock_overflows; | |
2aa44d05 IM |
424 | u64 idle_clock; |
425 | unsigned int clock_deep_idle_events; | |
529c7726 | 426 | u64 tick_timestamp; |
6aa645ea | 427 | |
1da177e4 LT |
428 | atomic_t nr_iowait; |
429 | ||
430 | #ifdef CONFIG_SMP | |
57d885fe | 431 | struct root_domain *rd; |
1da177e4 LT |
432 | struct sched_domain *sd; |
433 | ||
434 | /* For active balancing */ | |
435 | int active_balance; | |
436 | int push_cpu; | |
d8016491 IM |
437 | /* cpu of this runqueue: */ |
438 | int cpu; | |
1da177e4 | 439 | |
36c8b586 | 440 | struct task_struct *migration_thread; |
1da177e4 LT |
441 | struct list_head migration_queue; |
442 | #endif | |
443 | ||
444 | #ifdef CONFIG_SCHEDSTATS | |
445 | /* latency stats */ | |
446 | struct sched_info rq_sched_info; | |
447 | ||
448 | /* sys_sched_yield() stats */ | |
480b9434 KC |
449 | unsigned int yld_exp_empty; |
450 | unsigned int yld_act_empty; | |
451 | unsigned int yld_both_empty; | |
452 | unsigned int yld_count; | |
1da177e4 LT |
453 | |
454 | /* schedule() stats */ | |
480b9434 KC |
455 | unsigned int sched_switch; |
456 | unsigned int sched_count; | |
457 | unsigned int sched_goidle; | |
1da177e4 LT |
458 | |
459 | /* try_to_wake_up() stats */ | |
480b9434 KC |
460 | unsigned int ttwu_count; |
461 | unsigned int ttwu_local; | |
b8efb561 IM |
462 | |
463 | /* BKL stats */ | |
480b9434 | 464 | unsigned int bkl_count; |
1da177e4 | 465 | #endif |
fcb99371 | 466 | struct lock_class_key rq_lock_key; |
1da177e4 LT |
467 | }; |
468 | ||
f34e3b61 | 469 | static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues); |
1da177e4 | 470 | |
dd41f596 IM |
471 | static inline void check_preempt_curr(struct rq *rq, struct task_struct *p) |
472 | { | |
473 | rq->curr->sched_class->check_preempt_curr(rq, p); | |
474 | } | |
475 | ||
0a2966b4 CL |
476 | static inline int cpu_of(struct rq *rq) |
477 | { | |
478 | #ifdef CONFIG_SMP | |
479 | return rq->cpu; | |
480 | #else | |
481 | return 0; | |
482 | #endif | |
483 | } | |
484 | ||
20d315d4 | 485 | /* |
b04a0f4c IM |
486 | * Update the per-runqueue clock, as finegrained as the platform can give |
487 | * us, but without assuming monotonicity, etc.: | |
20d315d4 | 488 | */ |
b04a0f4c | 489 | static void __update_rq_clock(struct rq *rq) |
20d315d4 IM |
490 | { |
491 | u64 prev_raw = rq->prev_clock_raw; | |
492 | u64 now = sched_clock(); | |
493 | s64 delta = now - prev_raw; | |
494 | u64 clock = rq->clock; | |
495 | ||
b04a0f4c IM |
496 | #ifdef CONFIG_SCHED_DEBUG |
497 | WARN_ON_ONCE(cpu_of(rq) != smp_processor_id()); | |
498 | #endif | |
20d315d4 IM |
499 | /* |
500 | * Protect against sched_clock() occasionally going backwards: | |
501 | */ | |
502 | if (unlikely(delta < 0)) { | |
503 | clock++; | |
504 | rq->clock_warps++; | |
505 | } else { | |
506 | /* | |
507 | * Catch too large forward jumps too: | |
508 | */ | |
529c7726 IM |
509 | if (unlikely(clock + delta > rq->tick_timestamp + TICK_NSEC)) { |
510 | if (clock < rq->tick_timestamp + TICK_NSEC) | |
511 | clock = rq->tick_timestamp + TICK_NSEC; | |
512 | else | |
513 | clock++; | |
20d315d4 IM |
514 | rq->clock_overflows++; |
515 | } else { | |
516 | if (unlikely(delta > rq->clock_max_delta)) | |
517 | rq->clock_max_delta = delta; | |
518 | clock += delta; | |
519 | } | |
520 | } | |
521 | ||
522 | rq->prev_clock_raw = now; | |
523 | rq->clock = clock; | |
b04a0f4c | 524 | } |
20d315d4 | 525 | |
b04a0f4c IM |
526 | static void update_rq_clock(struct rq *rq) |
527 | { | |
528 | if (likely(smp_processor_id() == cpu_of(rq))) | |
529 | __update_rq_clock(rq); | |
20d315d4 IM |
530 | } |
531 | ||
674311d5 NP |
532 | /* |
533 | * The domain tree (rq->sd) is protected by RCU's quiescent state transition. | |
1a20ff27 | 534 | * See detach_destroy_domains: synchronize_sched for details. |
674311d5 NP |
535 | * |
536 | * The domain tree of any CPU may only be accessed from within | |
537 | * preempt-disabled sections. | |
538 | */ | |
48f24c4d IM |
539 | #define for_each_domain(cpu, __sd) \ |
540 | for (__sd = rcu_dereference(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent) | |
1da177e4 LT |
541 | |
542 | #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu))) | |
543 | #define this_rq() (&__get_cpu_var(runqueues)) | |
544 | #define task_rq(p) cpu_rq(task_cpu(p)) | |
545 | #define cpu_curr(cpu) (cpu_rq(cpu)->curr) | |
546 | ||
bf5c91ba IM |
547 | /* |
548 | * Tunables that become constants when CONFIG_SCHED_DEBUG is off: | |
549 | */ | |
550 | #ifdef CONFIG_SCHED_DEBUG | |
551 | # define const_debug __read_mostly | |
552 | #else | |
553 | # define const_debug static const | |
554 | #endif | |
555 | ||
556 | /* | |
557 | * Debugging: various feature bits | |
558 | */ | |
559 | enum { | |
bbdba7c0 | 560 | SCHED_FEAT_NEW_FAIR_SLEEPERS = 1, |
9612633a IM |
561 | SCHED_FEAT_WAKEUP_PREEMPT = 2, |
562 | SCHED_FEAT_START_DEBIT = 4, | |
41a2d6cf IM |
563 | SCHED_FEAT_TREE_AVG = 8, |
564 | SCHED_FEAT_APPROX_AVG = 16, | |
bf5c91ba IM |
565 | }; |
566 | ||
567 | const_debug unsigned int sysctl_sched_features = | |
8401f775 | 568 | SCHED_FEAT_NEW_FAIR_SLEEPERS * 1 | |
9612633a | 569 | SCHED_FEAT_WAKEUP_PREEMPT * 1 | |
8401f775 IM |
570 | SCHED_FEAT_START_DEBIT * 1 | |
571 | SCHED_FEAT_TREE_AVG * 0 | | |
9612633a | 572 | SCHED_FEAT_APPROX_AVG * 0; |
bf5c91ba IM |
573 | |
574 | #define sched_feat(x) (sysctl_sched_features & SCHED_FEAT_##x) | |
575 | ||
b82d9fdd PZ |
576 | /* |
577 | * Number of tasks to iterate in a single balance run. | |
578 | * Limited because this is done with IRQs disabled. | |
579 | */ | |
580 | const_debug unsigned int sysctl_sched_nr_migrate = 32; | |
581 | ||
e436d800 IM |
582 | /* |
583 | * For kernel-internal use: high-speed (but slightly incorrect) per-cpu | |
584 | * clock constructed from sched_clock(): | |
585 | */ | |
586 | unsigned long long cpu_clock(int cpu) | |
587 | { | |
e436d800 IM |
588 | unsigned long long now; |
589 | unsigned long flags; | |
b04a0f4c | 590 | struct rq *rq; |
e436d800 | 591 | |
2cd4d0ea | 592 | local_irq_save(flags); |
b04a0f4c | 593 | rq = cpu_rq(cpu); |
8ced5f69 IM |
594 | /* |
595 | * Only call sched_clock() if the scheduler has already been | |
596 | * initialized (some code might call cpu_clock() very early): | |
597 | */ | |
598 | if (rq->idle) | |
599 | update_rq_clock(rq); | |
b04a0f4c | 600 | now = rq->clock; |
2cd4d0ea | 601 | local_irq_restore(flags); |
e436d800 IM |
602 | |
603 | return now; | |
604 | } | |
a58f6f25 | 605 | EXPORT_SYMBOL_GPL(cpu_clock); |
e436d800 | 606 | |
1da177e4 | 607 | #ifndef prepare_arch_switch |
4866cde0 NP |
608 | # define prepare_arch_switch(next) do { } while (0) |
609 | #endif | |
610 | #ifndef finish_arch_switch | |
611 | # define finish_arch_switch(prev) do { } while (0) | |
612 | #endif | |
613 | ||
051a1d1a DA |
614 | static inline int task_current(struct rq *rq, struct task_struct *p) |
615 | { | |
616 | return rq->curr == p; | |
617 | } | |
618 | ||
4866cde0 | 619 | #ifndef __ARCH_WANT_UNLOCKED_CTXSW |
70b97a7f | 620 | static inline int task_running(struct rq *rq, struct task_struct *p) |
4866cde0 | 621 | { |
051a1d1a | 622 | return task_current(rq, p); |
4866cde0 NP |
623 | } |
624 | ||
70b97a7f | 625 | static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next) |
4866cde0 NP |
626 | { |
627 | } | |
628 | ||
70b97a7f | 629 | static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev) |
4866cde0 | 630 | { |
da04c035 IM |
631 | #ifdef CONFIG_DEBUG_SPINLOCK |
632 | /* this is a valid case when another task releases the spinlock */ | |
633 | rq->lock.owner = current; | |
634 | #endif | |
8a25d5de IM |
635 | /* |
636 | * If we are tracking spinlock dependencies then we have to | |
637 | * fix up the runqueue lock - which gets 'carried over' from | |
638 | * prev into current: | |
639 | */ | |
640 | spin_acquire(&rq->lock.dep_map, 0, 0, _THIS_IP_); | |
641 | ||
4866cde0 NP |
642 | spin_unlock_irq(&rq->lock); |
643 | } | |
644 | ||
645 | #else /* __ARCH_WANT_UNLOCKED_CTXSW */ | |
70b97a7f | 646 | static inline int task_running(struct rq *rq, struct task_struct *p) |
4866cde0 NP |
647 | { |
648 | #ifdef CONFIG_SMP | |
649 | return p->oncpu; | |
650 | #else | |
051a1d1a | 651 | return task_current(rq, p); |
4866cde0 NP |
652 | #endif |
653 | } | |
654 | ||
70b97a7f | 655 | static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next) |
4866cde0 NP |
656 | { |
657 | #ifdef CONFIG_SMP | |
658 | /* | |
659 | * We can optimise this out completely for !SMP, because the | |
660 | * SMP rebalancing from interrupt is the only thing that cares | |
661 | * here. | |
662 | */ | |
663 | next->oncpu = 1; | |
664 | #endif | |
665 | #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW | |
666 | spin_unlock_irq(&rq->lock); | |
667 | #else | |
668 | spin_unlock(&rq->lock); | |
669 | #endif | |
670 | } | |
671 | ||
70b97a7f | 672 | static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev) |
4866cde0 NP |
673 | { |
674 | #ifdef CONFIG_SMP | |
675 | /* | |
676 | * After ->oncpu is cleared, the task can be moved to a different CPU. | |
677 | * We must ensure this doesn't happen until the switch is completely | |
678 | * finished. | |
679 | */ | |
680 | smp_wmb(); | |
681 | prev->oncpu = 0; | |
682 | #endif | |
683 | #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW | |
684 | local_irq_enable(); | |
1da177e4 | 685 | #endif |
4866cde0 NP |
686 | } |
687 | #endif /* __ARCH_WANT_UNLOCKED_CTXSW */ | |
1da177e4 | 688 | |
b29739f9 IM |
689 | /* |
690 | * __task_rq_lock - lock the runqueue a given task resides on. | |
691 | * Must be called interrupts disabled. | |
692 | */ | |
70b97a7f | 693 | static inline struct rq *__task_rq_lock(struct task_struct *p) |
b29739f9 IM |
694 | __acquires(rq->lock) |
695 | { | |
3a5c359a AK |
696 | for (;;) { |
697 | struct rq *rq = task_rq(p); | |
698 | spin_lock(&rq->lock); | |
699 | if (likely(rq == task_rq(p))) | |
700 | return rq; | |
b29739f9 | 701 | spin_unlock(&rq->lock); |
b29739f9 | 702 | } |
b29739f9 IM |
703 | } |
704 | ||
1da177e4 LT |
705 | /* |
706 | * task_rq_lock - lock the runqueue a given task resides on and disable | |
41a2d6cf | 707 | * interrupts. Note the ordering: we can safely lookup the task_rq without |
1da177e4 LT |
708 | * explicitly disabling preemption. |
709 | */ | |
70b97a7f | 710 | static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags) |
1da177e4 LT |
711 | __acquires(rq->lock) |
712 | { | |
70b97a7f | 713 | struct rq *rq; |
1da177e4 | 714 | |
3a5c359a AK |
715 | for (;;) { |
716 | local_irq_save(*flags); | |
717 | rq = task_rq(p); | |
718 | spin_lock(&rq->lock); | |
719 | if (likely(rq == task_rq(p))) | |
720 | return rq; | |
1da177e4 | 721 | spin_unlock_irqrestore(&rq->lock, *flags); |
1da177e4 | 722 | } |
1da177e4 LT |
723 | } |
724 | ||
a9957449 | 725 | static void __task_rq_unlock(struct rq *rq) |
b29739f9 IM |
726 | __releases(rq->lock) |
727 | { | |
728 | spin_unlock(&rq->lock); | |
729 | } | |
730 | ||
70b97a7f | 731 | static inline void task_rq_unlock(struct rq *rq, unsigned long *flags) |
1da177e4 LT |
732 | __releases(rq->lock) |
733 | { | |
734 | spin_unlock_irqrestore(&rq->lock, *flags); | |
735 | } | |
736 | ||
1da177e4 | 737 | /* |
cc2a73b5 | 738 | * this_rq_lock - lock this runqueue and disable interrupts. |
1da177e4 | 739 | */ |
a9957449 | 740 | static struct rq *this_rq_lock(void) |
1da177e4 LT |
741 | __acquires(rq->lock) |
742 | { | |
70b97a7f | 743 | struct rq *rq; |
1da177e4 LT |
744 | |
745 | local_irq_disable(); | |
746 | rq = this_rq(); | |
747 | spin_lock(&rq->lock); | |
748 | ||
749 | return rq; | |
750 | } | |
751 | ||
1b9f19c2 | 752 | /* |
2aa44d05 | 753 | * We are going deep-idle (irqs are disabled): |
1b9f19c2 | 754 | */ |
2aa44d05 | 755 | void sched_clock_idle_sleep_event(void) |
1b9f19c2 | 756 | { |
2aa44d05 IM |
757 | struct rq *rq = cpu_rq(smp_processor_id()); |
758 | ||
759 | spin_lock(&rq->lock); | |
760 | __update_rq_clock(rq); | |
761 | spin_unlock(&rq->lock); | |
762 | rq->clock_deep_idle_events++; | |
763 | } | |
764 | EXPORT_SYMBOL_GPL(sched_clock_idle_sleep_event); | |
765 | ||
766 | /* | |
767 | * We just idled delta nanoseconds (called with irqs disabled): | |
768 | */ | |
769 | void sched_clock_idle_wakeup_event(u64 delta_ns) | |
770 | { | |
771 | struct rq *rq = cpu_rq(smp_processor_id()); | |
772 | u64 now = sched_clock(); | |
1b9f19c2 | 773 | |
2bacec8c | 774 | touch_softlockup_watchdog(); |
2aa44d05 IM |
775 | rq->idle_clock += delta_ns; |
776 | /* | |
777 | * Override the previous timestamp and ignore all | |
778 | * sched_clock() deltas that occured while we idled, | |
779 | * and use the PM-provided delta_ns to advance the | |
780 | * rq clock: | |
781 | */ | |
782 | spin_lock(&rq->lock); | |
783 | rq->prev_clock_raw = now; | |
784 | rq->clock += delta_ns; | |
785 | spin_unlock(&rq->lock); | |
1b9f19c2 | 786 | } |
2aa44d05 | 787 | EXPORT_SYMBOL_GPL(sched_clock_idle_wakeup_event); |
1b9f19c2 | 788 | |
c24d20db IM |
789 | /* |
790 | * resched_task - mark a task 'to be rescheduled now'. | |
791 | * | |
792 | * On UP this means the setting of the need_resched flag, on SMP it | |
793 | * might also involve a cross-CPU call to trigger the scheduler on | |
794 | * the target CPU. | |
795 | */ | |
796 | #ifdef CONFIG_SMP | |
797 | ||
798 | #ifndef tsk_is_polling | |
799 | #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG) | |
800 | #endif | |
801 | ||
802 | static void resched_task(struct task_struct *p) | |
803 | { | |
804 | int cpu; | |
805 | ||
806 | assert_spin_locked(&task_rq(p)->lock); | |
807 | ||
808 | if (unlikely(test_tsk_thread_flag(p, TIF_NEED_RESCHED))) | |
809 | return; | |
810 | ||
811 | set_tsk_thread_flag(p, TIF_NEED_RESCHED); | |
812 | ||
813 | cpu = task_cpu(p); | |
814 | if (cpu == smp_processor_id()) | |
815 | return; | |
816 | ||
817 | /* NEED_RESCHED must be visible before we test polling */ | |
818 | smp_mb(); | |
819 | if (!tsk_is_polling(p)) | |
820 | smp_send_reschedule(cpu); | |
821 | } | |
822 | ||
823 | static void resched_cpu(int cpu) | |
824 | { | |
825 | struct rq *rq = cpu_rq(cpu); | |
826 | unsigned long flags; | |
827 | ||
828 | if (!spin_trylock_irqsave(&rq->lock, flags)) | |
829 | return; | |
830 | resched_task(cpu_curr(cpu)); | |
831 | spin_unlock_irqrestore(&rq->lock, flags); | |
832 | } | |
833 | #else | |
834 | static inline void resched_task(struct task_struct *p) | |
835 | { | |
836 | assert_spin_locked(&task_rq(p)->lock); | |
837 | set_tsk_need_resched(p); | |
838 | } | |
839 | #endif | |
840 | ||
45bf76df IM |
841 | #if BITS_PER_LONG == 32 |
842 | # define WMULT_CONST (~0UL) | |
843 | #else | |
844 | # define WMULT_CONST (1UL << 32) | |
845 | #endif | |
846 | ||
847 | #define WMULT_SHIFT 32 | |
848 | ||
194081eb IM |
849 | /* |
850 | * Shift right and round: | |
851 | */ | |
cf2ab469 | 852 | #define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y)) |
194081eb | 853 | |
cb1c4fc9 | 854 | static unsigned long |
45bf76df IM |
855 | calc_delta_mine(unsigned long delta_exec, unsigned long weight, |
856 | struct load_weight *lw) | |
857 | { | |
858 | u64 tmp; | |
859 | ||
860 | if (unlikely(!lw->inv_weight)) | |
194081eb | 861 | lw->inv_weight = (WMULT_CONST - lw->weight/2) / lw->weight + 1; |
45bf76df IM |
862 | |
863 | tmp = (u64)delta_exec * weight; | |
864 | /* | |
865 | * Check whether we'd overflow the 64-bit multiplication: | |
866 | */ | |
194081eb | 867 | if (unlikely(tmp > WMULT_CONST)) |
cf2ab469 | 868 | tmp = SRR(SRR(tmp, WMULT_SHIFT/2) * lw->inv_weight, |
194081eb IM |
869 | WMULT_SHIFT/2); |
870 | else | |
cf2ab469 | 871 | tmp = SRR(tmp * lw->inv_weight, WMULT_SHIFT); |
45bf76df | 872 | |
ecf691da | 873 | return (unsigned long)min(tmp, (u64)(unsigned long)LONG_MAX); |
45bf76df IM |
874 | } |
875 | ||
876 | static inline unsigned long | |
877 | calc_delta_fair(unsigned long delta_exec, struct load_weight *lw) | |
878 | { | |
879 | return calc_delta_mine(delta_exec, NICE_0_LOAD, lw); | |
880 | } | |
881 | ||
1091985b | 882 | static inline void update_load_add(struct load_weight *lw, unsigned long inc) |
45bf76df IM |
883 | { |
884 | lw->weight += inc; | |
45bf76df IM |
885 | } |
886 | ||
1091985b | 887 | static inline void update_load_sub(struct load_weight *lw, unsigned long dec) |
45bf76df IM |
888 | { |
889 | lw->weight -= dec; | |
45bf76df IM |
890 | } |
891 | ||
2dd73a4f PW |
892 | /* |
893 | * To aid in avoiding the subversion of "niceness" due to uneven distribution | |
894 | * of tasks with abnormal "nice" values across CPUs the contribution that | |
895 | * each task makes to its run queue's load is weighted according to its | |
41a2d6cf | 896 | * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a |
2dd73a4f PW |
897 | * scaled version of the new time slice allocation that they receive on time |
898 | * slice expiry etc. | |
899 | */ | |
900 | ||
dd41f596 IM |
901 | #define WEIGHT_IDLEPRIO 2 |
902 | #define WMULT_IDLEPRIO (1 << 31) | |
903 | ||
904 | /* | |
905 | * Nice levels are multiplicative, with a gentle 10% change for every | |
906 | * nice level changed. I.e. when a CPU-bound task goes from nice 0 to | |
907 | * nice 1, it will get ~10% less CPU time than another CPU-bound task | |
908 | * that remained on nice 0. | |
909 | * | |
910 | * The "10% effect" is relative and cumulative: from _any_ nice level, | |
911 | * if you go up 1 level, it's -10% CPU usage, if you go down 1 level | |
f9153ee6 IM |
912 | * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25. |
913 | * If a task goes up by ~10% and another task goes down by ~10% then | |
914 | * the relative distance between them is ~25%.) | |
dd41f596 IM |
915 | */ |
916 | static const int prio_to_weight[40] = { | |
254753dc IM |
917 | /* -20 */ 88761, 71755, 56483, 46273, 36291, |
918 | /* -15 */ 29154, 23254, 18705, 14949, 11916, | |
919 | /* -10 */ 9548, 7620, 6100, 4904, 3906, | |
920 | /* -5 */ 3121, 2501, 1991, 1586, 1277, | |
921 | /* 0 */ 1024, 820, 655, 526, 423, | |
922 | /* 5 */ 335, 272, 215, 172, 137, | |
923 | /* 10 */ 110, 87, 70, 56, 45, | |
924 | /* 15 */ 36, 29, 23, 18, 15, | |
dd41f596 IM |
925 | }; |
926 | ||
5714d2de IM |
927 | /* |
928 | * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated. | |
929 | * | |
930 | * In cases where the weight does not change often, we can use the | |
931 | * precalculated inverse to speed up arithmetics by turning divisions | |
932 | * into multiplications: | |
933 | */ | |
dd41f596 | 934 | static const u32 prio_to_wmult[40] = { |
254753dc IM |
935 | /* -20 */ 48388, 59856, 76040, 92818, 118348, |
936 | /* -15 */ 147320, 184698, 229616, 287308, 360437, | |
937 | /* -10 */ 449829, 563644, 704093, 875809, 1099582, | |
938 | /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326, | |
939 | /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587, | |
940 | /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126, | |
941 | /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717, | |
942 | /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153, | |
dd41f596 | 943 | }; |
2dd73a4f | 944 | |
dd41f596 IM |
945 | static void activate_task(struct rq *rq, struct task_struct *p, int wakeup); |
946 | ||
947 | /* | |
948 | * runqueue iterator, to support SMP load-balancing between different | |
949 | * scheduling classes, without having to expose their internal data | |
950 | * structures to the load-balancing proper: | |
951 | */ | |
952 | struct rq_iterator { | |
953 | void *arg; | |
954 | struct task_struct *(*start)(void *); | |
955 | struct task_struct *(*next)(void *); | |
956 | }; | |
957 | ||
e1d1484f PW |
958 | #ifdef CONFIG_SMP |
959 | static unsigned long | |
960 | balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
961 | unsigned long max_load_move, struct sched_domain *sd, | |
962 | enum cpu_idle_type idle, int *all_pinned, | |
963 | int *this_best_prio, struct rq_iterator *iterator); | |
964 | ||
965 | static int | |
966 | iter_move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
967 | struct sched_domain *sd, enum cpu_idle_type idle, | |
968 | struct rq_iterator *iterator); | |
e1d1484f | 969 | #endif |
dd41f596 | 970 | |
d842de87 SV |
971 | #ifdef CONFIG_CGROUP_CPUACCT |
972 | static void cpuacct_charge(struct task_struct *tsk, u64 cputime); | |
973 | #else | |
974 | static inline void cpuacct_charge(struct task_struct *tsk, u64 cputime) {} | |
975 | #endif | |
976 | ||
58e2d4ca SV |
977 | static inline void inc_cpu_load(struct rq *rq, unsigned long load) |
978 | { | |
979 | update_load_add(&rq->load, load); | |
980 | } | |
981 | ||
982 | static inline void dec_cpu_load(struct rq *rq, unsigned long load) | |
983 | { | |
984 | update_load_sub(&rq->load, load); | |
985 | } | |
986 | ||
e7693a36 GH |
987 | #ifdef CONFIG_SMP |
988 | static unsigned long source_load(int cpu, int type); | |
989 | static unsigned long target_load(int cpu, int type); | |
990 | static unsigned long cpu_avg_load_per_task(int cpu); | |
991 | static int task_hot(struct task_struct *p, u64 now, struct sched_domain *sd); | |
992 | #endif /* CONFIG_SMP */ | |
993 | ||
dd41f596 | 994 | #include "sched_stats.h" |
dd41f596 | 995 | #include "sched_idletask.c" |
5522d5d5 IM |
996 | #include "sched_fair.c" |
997 | #include "sched_rt.c" | |
dd41f596 IM |
998 | #ifdef CONFIG_SCHED_DEBUG |
999 | # include "sched_debug.c" | |
1000 | #endif | |
1001 | ||
1002 | #define sched_class_highest (&rt_sched_class) | |
1003 | ||
e5fa2237 | 1004 | static void inc_nr_running(struct task_struct *p, struct rq *rq) |
9c217245 IM |
1005 | { |
1006 | rq->nr_running++; | |
9c217245 IM |
1007 | } |
1008 | ||
db53181e | 1009 | static void dec_nr_running(struct task_struct *p, struct rq *rq) |
9c217245 IM |
1010 | { |
1011 | rq->nr_running--; | |
9c217245 IM |
1012 | } |
1013 | ||
45bf76df IM |
1014 | static void set_load_weight(struct task_struct *p) |
1015 | { | |
1016 | if (task_has_rt_policy(p)) { | |
dd41f596 IM |
1017 | p->se.load.weight = prio_to_weight[0] * 2; |
1018 | p->se.load.inv_weight = prio_to_wmult[0] >> 1; | |
1019 | return; | |
1020 | } | |
45bf76df | 1021 | |
dd41f596 IM |
1022 | /* |
1023 | * SCHED_IDLE tasks get minimal weight: | |
1024 | */ | |
1025 | if (p->policy == SCHED_IDLE) { | |
1026 | p->se.load.weight = WEIGHT_IDLEPRIO; | |
1027 | p->se.load.inv_weight = WMULT_IDLEPRIO; | |
1028 | return; | |
1029 | } | |
71f8bd46 | 1030 | |
dd41f596 IM |
1031 | p->se.load.weight = prio_to_weight[p->static_prio - MAX_RT_PRIO]; |
1032 | p->se.load.inv_weight = prio_to_wmult[p->static_prio - MAX_RT_PRIO]; | |
71f8bd46 IM |
1033 | } |
1034 | ||
8159f87e | 1035 | static void enqueue_task(struct rq *rq, struct task_struct *p, int wakeup) |
71f8bd46 | 1036 | { |
dd41f596 | 1037 | sched_info_queued(p); |
fd390f6a | 1038 | p->sched_class->enqueue_task(rq, p, wakeup); |
dd41f596 | 1039 | p->se.on_rq = 1; |
71f8bd46 IM |
1040 | } |
1041 | ||
69be72c1 | 1042 | static void dequeue_task(struct rq *rq, struct task_struct *p, int sleep) |
71f8bd46 | 1043 | { |
f02231e5 | 1044 | p->sched_class->dequeue_task(rq, p, sleep); |
dd41f596 | 1045 | p->se.on_rq = 0; |
71f8bd46 IM |
1046 | } |
1047 | ||
14531189 | 1048 | /* |
dd41f596 | 1049 | * __normal_prio - return the priority that is based on the static prio |
14531189 | 1050 | */ |
14531189 IM |
1051 | static inline int __normal_prio(struct task_struct *p) |
1052 | { | |
dd41f596 | 1053 | return p->static_prio; |
14531189 IM |
1054 | } |
1055 | ||
b29739f9 IM |
1056 | /* |
1057 | * Calculate the expected normal priority: i.e. priority | |
1058 | * without taking RT-inheritance into account. Might be | |
1059 | * boosted by interactivity modifiers. Changes upon fork, | |
1060 | * setprio syscalls, and whenever the interactivity | |
1061 | * estimator recalculates. | |
1062 | */ | |
36c8b586 | 1063 | static inline int normal_prio(struct task_struct *p) |
b29739f9 IM |
1064 | { |
1065 | int prio; | |
1066 | ||
e05606d3 | 1067 | if (task_has_rt_policy(p)) |
b29739f9 IM |
1068 | prio = MAX_RT_PRIO-1 - p->rt_priority; |
1069 | else | |
1070 | prio = __normal_prio(p); | |
1071 | return prio; | |
1072 | } | |
1073 | ||
1074 | /* | |
1075 | * Calculate the current priority, i.e. the priority | |
1076 | * taken into account by the scheduler. This value might | |
1077 | * be boosted by RT tasks, or might be boosted by | |
1078 | * interactivity modifiers. Will be RT if the task got | |
1079 | * RT-boosted. If not then it returns p->normal_prio. | |
1080 | */ | |
36c8b586 | 1081 | static int effective_prio(struct task_struct *p) |
b29739f9 IM |
1082 | { |
1083 | p->normal_prio = normal_prio(p); | |
1084 | /* | |
1085 | * If we are RT tasks or we were boosted to RT priority, | |
1086 | * keep the priority unchanged. Otherwise, update priority | |
1087 | * to the normal priority: | |
1088 | */ | |
1089 | if (!rt_prio(p->prio)) | |
1090 | return p->normal_prio; | |
1091 | return p->prio; | |
1092 | } | |
1093 | ||
1da177e4 | 1094 | /* |
dd41f596 | 1095 | * activate_task - move a task to the runqueue. |
1da177e4 | 1096 | */ |
dd41f596 | 1097 | static void activate_task(struct rq *rq, struct task_struct *p, int wakeup) |
1da177e4 | 1098 | { |
dd41f596 IM |
1099 | if (p->state == TASK_UNINTERRUPTIBLE) |
1100 | rq->nr_uninterruptible--; | |
1da177e4 | 1101 | |
8159f87e | 1102 | enqueue_task(rq, p, wakeup); |
e5fa2237 | 1103 | inc_nr_running(p, rq); |
1da177e4 LT |
1104 | } |
1105 | ||
1da177e4 LT |
1106 | /* |
1107 | * deactivate_task - remove a task from the runqueue. | |
1108 | */ | |
2e1cb74a | 1109 | static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep) |
1da177e4 | 1110 | { |
dd41f596 IM |
1111 | if (p->state == TASK_UNINTERRUPTIBLE) |
1112 | rq->nr_uninterruptible++; | |
1113 | ||
69be72c1 | 1114 | dequeue_task(rq, p, sleep); |
db53181e | 1115 | dec_nr_running(p, rq); |
1da177e4 LT |
1116 | } |
1117 | ||
1da177e4 LT |
1118 | /** |
1119 | * task_curr - is this task currently executing on a CPU? | |
1120 | * @p: the task in question. | |
1121 | */ | |
36c8b586 | 1122 | inline int task_curr(const struct task_struct *p) |
1da177e4 LT |
1123 | { |
1124 | return cpu_curr(task_cpu(p)) == p; | |
1125 | } | |
1126 | ||
2dd73a4f PW |
1127 | /* Used instead of source_load when we know the type == 0 */ |
1128 | unsigned long weighted_cpuload(const int cpu) | |
1129 | { | |
495eca49 | 1130 | return cpu_rq(cpu)->load.weight; |
dd41f596 IM |
1131 | } |
1132 | ||
1133 | static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu) | |
1134 | { | |
ce96b5ac | 1135 | set_task_cfs_rq(p, cpu); |
dd41f596 | 1136 | #ifdef CONFIG_SMP |
ce96b5ac DA |
1137 | /* |
1138 | * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be | |
1139 | * successfuly executed on another CPU. We must ensure that updates of | |
1140 | * per-task data have been completed by this moment. | |
1141 | */ | |
1142 | smp_wmb(); | |
dd41f596 | 1143 | task_thread_info(p)->cpu = cpu; |
dd41f596 | 1144 | #endif |
2dd73a4f PW |
1145 | } |
1146 | ||
1da177e4 | 1147 | #ifdef CONFIG_SMP |
c65cc870 | 1148 | |
cc367732 IM |
1149 | /* |
1150 | * Is this task likely cache-hot: | |
1151 | */ | |
e7693a36 | 1152 | static int |
cc367732 IM |
1153 | task_hot(struct task_struct *p, u64 now, struct sched_domain *sd) |
1154 | { | |
1155 | s64 delta; | |
1156 | ||
1157 | if (p->sched_class != &fair_sched_class) | |
1158 | return 0; | |
1159 | ||
6bc1665b IM |
1160 | if (sysctl_sched_migration_cost == -1) |
1161 | return 1; | |
1162 | if (sysctl_sched_migration_cost == 0) | |
1163 | return 0; | |
1164 | ||
cc367732 IM |
1165 | delta = now - p->se.exec_start; |
1166 | ||
1167 | return delta < (s64)sysctl_sched_migration_cost; | |
1168 | } | |
1169 | ||
1170 | ||
dd41f596 | 1171 | void set_task_cpu(struct task_struct *p, unsigned int new_cpu) |
c65cc870 | 1172 | { |
dd41f596 IM |
1173 | int old_cpu = task_cpu(p); |
1174 | struct rq *old_rq = cpu_rq(old_cpu), *new_rq = cpu_rq(new_cpu); | |
2830cf8c SV |
1175 | struct cfs_rq *old_cfsrq = task_cfs_rq(p), |
1176 | *new_cfsrq = cpu_cfs_rq(old_cfsrq, new_cpu); | |
bbdba7c0 | 1177 | u64 clock_offset; |
dd41f596 IM |
1178 | |
1179 | clock_offset = old_rq->clock - new_rq->clock; | |
6cfb0d5d IM |
1180 | |
1181 | #ifdef CONFIG_SCHEDSTATS | |
1182 | if (p->se.wait_start) | |
1183 | p->se.wait_start -= clock_offset; | |
dd41f596 IM |
1184 | if (p->se.sleep_start) |
1185 | p->se.sleep_start -= clock_offset; | |
1186 | if (p->se.block_start) | |
1187 | p->se.block_start -= clock_offset; | |
cc367732 IM |
1188 | if (old_cpu != new_cpu) { |
1189 | schedstat_inc(p, se.nr_migrations); | |
1190 | if (task_hot(p, old_rq->clock, NULL)) | |
1191 | schedstat_inc(p, se.nr_forced2_migrations); | |
1192 | } | |
6cfb0d5d | 1193 | #endif |
2830cf8c SV |
1194 | p->se.vruntime -= old_cfsrq->min_vruntime - |
1195 | new_cfsrq->min_vruntime; | |
dd41f596 IM |
1196 | |
1197 | __set_task_cpu(p, new_cpu); | |
c65cc870 IM |
1198 | } |
1199 | ||
70b97a7f | 1200 | struct migration_req { |
1da177e4 | 1201 | struct list_head list; |
1da177e4 | 1202 | |
36c8b586 | 1203 | struct task_struct *task; |
1da177e4 LT |
1204 | int dest_cpu; |
1205 | ||
1da177e4 | 1206 | struct completion done; |
70b97a7f | 1207 | }; |
1da177e4 LT |
1208 | |
1209 | /* | |
1210 | * The task's runqueue lock must be held. | |
1211 | * Returns true if you have to wait for migration thread. | |
1212 | */ | |
36c8b586 | 1213 | static int |
70b97a7f | 1214 | migrate_task(struct task_struct *p, int dest_cpu, struct migration_req *req) |
1da177e4 | 1215 | { |
70b97a7f | 1216 | struct rq *rq = task_rq(p); |
1da177e4 LT |
1217 | |
1218 | /* | |
1219 | * If the task is not on a runqueue (and not running), then | |
1220 | * it is sufficient to simply update the task's cpu field. | |
1221 | */ | |
dd41f596 | 1222 | if (!p->se.on_rq && !task_running(rq, p)) { |
1da177e4 LT |
1223 | set_task_cpu(p, dest_cpu); |
1224 | return 0; | |
1225 | } | |
1226 | ||
1227 | init_completion(&req->done); | |
1da177e4 LT |
1228 | req->task = p; |
1229 | req->dest_cpu = dest_cpu; | |
1230 | list_add(&req->list, &rq->migration_queue); | |
48f24c4d | 1231 | |
1da177e4 LT |
1232 | return 1; |
1233 | } | |
1234 | ||
1235 | /* | |
1236 | * wait_task_inactive - wait for a thread to unschedule. | |
1237 | * | |
1238 | * The caller must ensure that the task *will* unschedule sometime soon, | |
1239 | * else this function might spin for a *long* time. This function can't | |
1240 | * be called with interrupts off, or it may introduce deadlock with | |
1241 | * smp_call_function() if an IPI is sent by the same process we are | |
1242 | * waiting to become inactive. | |
1243 | */ | |
36c8b586 | 1244 | void wait_task_inactive(struct task_struct *p) |
1da177e4 LT |
1245 | { |
1246 | unsigned long flags; | |
dd41f596 | 1247 | int running, on_rq; |
70b97a7f | 1248 | struct rq *rq; |
1da177e4 | 1249 | |
3a5c359a AK |
1250 | for (;;) { |
1251 | /* | |
1252 | * We do the initial early heuristics without holding | |
1253 | * any task-queue locks at all. We'll only try to get | |
1254 | * the runqueue lock when things look like they will | |
1255 | * work out! | |
1256 | */ | |
1257 | rq = task_rq(p); | |
fa490cfd | 1258 | |
3a5c359a AK |
1259 | /* |
1260 | * If the task is actively running on another CPU | |
1261 | * still, just relax and busy-wait without holding | |
1262 | * any locks. | |
1263 | * | |
1264 | * NOTE! Since we don't hold any locks, it's not | |
1265 | * even sure that "rq" stays as the right runqueue! | |
1266 | * But we don't care, since "task_running()" will | |
1267 | * return false if the runqueue has changed and p | |
1268 | * is actually now running somewhere else! | |
1269 | */ | |
1270 | while (task_running(rq, p)) | |
1271 | cpu_relax(); | |
fa490cfd | 1272 | |
3a5c359a AK |
1273 | /* |
1274 | * Ok, time to look more closely! We need the rq | |
1275 | * lock now, to be *sure*. If we're wrong, we'll | |
1276 | * just go back and repeat. | |
1277 | */ | |
1278 | rq = task_rq_lock(p, &flags); | |
1279 | running = task_running(rq, p); | |
1280 | on_rq = p->se.on_rq; | |
1281 | task_rq_unlock(rq, &flags); | |
fa490cfd | 1282 | |
3a5c359a AK |
1283 | /* |
1284 | * Was it really running after all now that we | |
1285 | * checked with the proper locks actually held? | |
1286 | * | |
1287 | * Oops. Go back and try again.. | |
1288 | */ | |
1289 | if (unlikely(running)) { | |
1290 | cpu_relax(); | |
1291 | continue; | |
1292 | } | |
fa490cfd | 1293 | |
3a5c359a AK |
1294 | /* |
1295 | * It's not enough that it's not actively running, | |
1296 | * it must be off the runqueue _entirely_, and not | |
1297 | * preempted! | |
1298 | * | |
1299 | * So if it wa still runnable (but just not actively | |
1300 | * running right now), it's preempted, and we should | |
1301 | * yield - it could be a while. | |
1302 | */ | |
1303 | if (unlikely(on_rq)) { | |
1304 | schedule_timeout_uninterruptible(1); | |
1305 | continue; | |
1306 | } | |
fa490cfd | 1307 | |
3a5c359a AK |
1308 | /* |
1309 | * Ahh, all good. It wasn't running, and it wasn't | |
1310 | * runnable, which means that it will never become | |
1311 | * running in the future either. We're all done! | |
1312 | */ | |
1313 | break; | |
1314 | } | |
1da177e4 LT |
1315 | } |
1316 | ||
1317 | /*** | |
1318 | * kick_process - kick a running thread to enter/exit the kernel | |
1319 | * @p: the to-be-kicked thread | |
1320 | * | |
1321 | * Cause a process which is running on another CPU to enter | |
1322 | * kernel-mode, without any delay. (to get signals handled.) | |
1323 | * | |
1324 | * NOTE: this function doesnt have to take the runqueue lock, | |
1325 | * because all it wants to ensure is that the remote task enters | |
1326 | * the kernel. If the IPI races and the task has been migrated | |
1327 | * to another CPU then no harm is done and the purpose has been | |
1328 | * achieved as well. | |
1329 | */ | |
36c8b586 | 1330 | void kick_process(struct task_struct *p) |
1da177e4 LT |
1331 | { |
1332 | int cpu; | |
1333 | ||
1334 | preempt_disable(); | |
1335 | cpu = task_cpu(p); | |
1336 | if ((cpu != smp_processor_id()) && task_curr(p)) | |
1337 | smp_send_reschedule(cpu); | |
1338 | preempt_enable(); | |
1339 | } | |
1340 | ||
1341 | /* | |
2dd73a4f PW |
1342 | * Return a low guess at the load of a migration-source cpu weighted |
1343 | * according to the scheduling class and "nice" value. | |
1da177e4 LT |
1344 | * |
1345 | * We want to under-estimate the load of migration sources, to | |
1346 | * balance conservatively. | |
1347 | */ | |
a9957449 | 1348 | static unsigned long source_load(int cpu, int type) |
1da177e4 | 1349 | { |
70b97a7f | 1350 | struct rq *rq = cpu_rq(cpu); |
dd41f596 | 1351 | unsigned long total = weighted_cpuload(cpu); |
2dd73a4f | 1352 | |
3b0bd9bc | 1353 | if (type == 0) |
dd41f596 | 1354 | return total; |
b910472d | 1355 | |
dd41f596 | 1356 | return min(rq->cpu_load[type-1], total); |
1da177e4 LT |
1357 | } |
1358 | ||
1359 | /* | |
2dd73a4f PW |
1360 | * Return a high guess at the load of a migration-target cpu weighted |
1361 | * according to the scheduling class and "nice" value. | |
1da177e4 | 1362 | */ |
a9957449 | 1363 | static unsigned long target_load(int cpu, int type) |
1da177e4 | 1364 | { |
70b97a7f | 1365 | struct rq *rq = cpu_rq(cpu); |
dd41f596 | 1366 | unsigned long total = weighted_cpuload(cpu); |
2dd73a4f | 1367 | |
7897986b | 1368 | if (type == 0) |
dd41f596 | 1369 | return total; |
3b0bd9bc | 1370 | |
dd41f596 | 1371 | return max(rq->cpu_load[type-1], total); |
2dd73a4f PW |
1372 | } |
1373 | ||
1374 | /* | |
1375 | * Return the average load per task on the cpu's run queue | |
1376 | */ | |
e7693a36 | 1377 | static unsigned long cpu_avg_load_per_task(int cpu) |
2dd73a4f | 1378 | { |
70b97a7f | 1379 | struct rq *rq = cpu_rq(cpu); |
dd41f596 | 1380 | unsigned long total = weighted_cpuload(cpu); |
2dd73a4f PW |
1381 | unsigned long n = rq->nr_running; |
1382 | ||
dd41f596 | 1383 | return n ? total / n : SCHED_LOAD_SCALE; |
1da177e4 LT |
1384 | } |
1385 | ||
147cbb4b NP |
1386 | /* |
1387 | * find_idlest_group finds and returns the least busy CPU group within the | |
1388 | * domain. | |
1389 | */ | |
1390 | static struct sched_group * | |
1391 | find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu) | |
1392 | { | |
1393 | struct sched_group *idlest = NULL, *this = NULL, *group = sd->groups; | |
1394 | unsigned long min_load = ULONG_MAX, this_load = 0; | |
1395 | int load_idx = sd->forkexec_idx; | |
1396 | int imbalance = 100 + (sd->imbalance_pct-100)/2; | |
1397 | ||
1398 | do { | |
1399 | unsigned long load, avg_load; | |
1400 | int local_group; | |
1401 | int i; | |
1402 | ||
da5a5522 BD |
1403 | /* Skip over this group if it has no CPUs allowed */ |
1404 | if (!cpus_intersects(group->cpumask, p->cpus_allowed)) | |
3a5c359a | 1405 | continue; |
da5a5522 | 1406 | |
147cbb4b | 1407 | local_group = cpu_isset(this_cpu, group->cpumask); |
147cbb4b NP |
1408 | |
1409 | /* Tally up the load of all CPUs in the group */ | |
1410 | avg_load = 0; | |
1411 | ||
1412 | for_each_cpu_mask(i, group->cpumask) { | |
1413 | /* Bias balancing toward cpus of our domain */ | |
1414 | if (local_group) | |
1415 | load = source_load(i, load_idx); | |
1416 | else | |
1417 | load = target_load(i, load_idx); | |
1418 | ||
1419 | avg_load += load; | |
1420 | } | |
1421 | ||
1422 | /* Adjust by relative CPU power of the group */ | |
5517d86b ED |
1423 | avg_load = sg_div_cpu_power(group, |
1424 | avg_load * SCHED_LOAD_SCALE); | |
147cbb4b NP |
1425 | |
1426 | if (local_group) { | |
1427 | this_load = avg_load; | |
1428 | this = group; | |
1429 | } else if (avg_load < min_load) { | |
1430 | min_load = avg_load; | |
1431 | idlest = group; | |
1432 | } | |
3a5c359a | 1433 | } while (group = group->next, group != sd->groups); |
147cbb4b NP |
1434 | |
1435 | if (!idlest || 100*this_load < imbalance*min_load) | |
1436 | return NULL; | |
1437 | return idlest; | |
1438 | } | |
1439 | ||
1440 | /* | |
0feaece9 | 1441 | * find_idlest_cpu - find the idlest cpu among the cpus in group. |
147cbb4b | 1442 | */ |
95cdf3b7 IM |
1443 | static int |
1444 | find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu) | |
147cbb4b | 1445 | { |
da5a5522 | 1446 | cpumask_t tmp; |
147cbb4b NP |
1447 | unsigned long load, min_load = ULONG_MAX; |
1448 | int idlest = -1; | |
1449 | int i; | |
1450 | ||
da5a5522 BD |
1451 | /* Traverse only the allowed CPUs */ |
1452 | cpus_and(tmp, group->cpumask, p->cpus_allowed); | |
1453 | ||
1454 | for_each_cpu_mask(i, tmp) { | |
2dd73a4f | 1455 | load = weighted_cpuload(i); |
147cbb4b NP |
1456 | |
1457 | if (load < min_load || (load == min_load && i == this_cpu)) { | |
1458 | min_load = load; | |
1459 | idlest = i; | |
1460 | } | |
1461 | } | |
1462 | ||
1463 | return idlest; | |
1464 | } | |
1465 | ||
476d139c NP |
1466 | /* |
1467 | * sched_balance_self: balance the current task (running on cpu) in domains | |
1468 | * that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and | |
1469 | * SD_BALANCE_EXEC. | |
1470 | * | |
1471 | * Balance, ie. select the least loaded group. | |
1472 | * | |
1473 | * Returns the target CPU number, or the same CPU if no balancing is needed. | |
1474 | * | |
1475 | * preempt must be disabled. | |
1476 | */ | |
1477 | static int sched_balance_self(int cpu, int flag) | |
1478 | { | |
1479 | struct task_struct *t = current; | |
1480 | struct sched_domain *tmp, *sd = NULL; | |
147cbb4b | 1481 | |
c96d145e | 1482 | for_each_domain(cpu, tmp) { |
9761eea8 IM |
1483 | /* |
1484 | * If power savings logic is enabled for a domain, stop there. | |
1485 | */ | |
5c45bf27 SS |
1486 | if (tmp->flags & SD_POWERSAVINGS_BALANCE) |
1487 | break; | |
476d139c NP |
1488 | if (tmp->flags & flag) |
1489 | sd = tmp; | |
c96d145e | 1490 | } |
476d139c NP |
1491 | |
1492 | while (sd) { | |
1493 | cpumask_t span; | |
1494 | struct sched_group *group; | |
1a848870 SS |
1495 | int new_cpu, weight; |
1496 | ||
1497 | if (!(sd->flags & flag)) { | |
1498 | sd = sd->child; | |
1499 | continue; | |
1500 | } | |
476d139c NP |
1501 | |
1502 | span = sd->span; | |
1503 | group = find_idlest_group(sd, t, cpu); | |
1a848870 SS |
1504 | if (!group) { |
1505 | sd = sd->child; | |
1506 | continue; | |
1507 | } | |
476d139c | 1508 | |
da5a5522 | 1509 | new_cpu = find_idlest_cpu(group, t, cpu); |
1a848870 SS |
1510 | if (new_cpu == -1 || new_cpu == cpu) { |
1511 | /* Now try balancing at a lower domain level of cpu */ | |
1512 | sd = sd->child; | |
1513 | continue; | |
1514 | } | |
476d139c | 1515 | |
1a848870 | 1516 | /* Now try balancing at a lower domain level of new_cpu */ |
476d139c | 1517 | cpu = new_cpu; |
476d139c NP |
1518 | sd = NULL; |
1519 | weight = cpus_weight(span); | |
1520 | for_each_domain(cpu, tmp) { | |
1521 | if (weight <= cpus_weight(tmp->span)) | |
1522 | break; | |
1523 | if (tmp->flags & flag) | |
1524 | sd = tmp; | |
1525 | } | |
1526 | /* while loop will break here if sd == NULL */ | |
1527 | } | |
1528 | ||
1529 | return cpu; | |
1530 | } | |
1531 | ||
1532 | #endif /* CONFIG_SMP */ | |
1da177e4 | 1533 | |
1da177e4 LT |
1534 | /*** |
1535 | * try_to_wake_up - wake up a thread | |
1536 | * @p: the to-be-woken-up thread | |
1537 | * @state: the mask of task states that can be woken | |
1538 | * @sync: do a synchronous wakeup? | |
1539 | * | |
1540 | * Put it on the run-queue if it's not already there. The "current" | |
1541 | * thread is always on the run-queue (except when the actual | |
1542 | * re-schedule is in progress), and as such you're allowed to do | |
1543 | * the simpler "current->state = TASK_RUNNING" to mark yourself | |
1544 | * runnable without the overhead of this. | |
1545 | * | |
1546 | * returns failure only if the task is already active. | |
1547 | */ | |
36c8b586 | 1548 | static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync) |
1da177e4 | 1549 | { |
cc367732 | 1550 | int cpu, orig_cpu, this_cpu, success = 0; |
1da177e4 LT |
1551 | unsigned long flags; |
1552 | long old_state; | |
70b97a7f | 1553 | struct rq *rq; |
1da177e4 | 1554 | #ifdef CONFIG_SMP |
1da177e4 LT |
1555 | int new_cpu; |
1556 | #endif | |
1557 | ||
1558 | rq = task_rq_lock(p, &flags); | |
1559 | old_state = p->state; | |
1560 | if (!(old_state & state)) | |
1561 | goto out; | |
1562 | ||
dd41f596 | 1563 | if (p->se.on_rq) |
1da177e4 LT |
1564 | goto out_running; |
1565 | ||
1566 | cpu = task_cpu(p); | |
cc367732 | 1567 | orig_cpu = cpu; |
1da177e4 LT |
1568 | this_cpu = smp_processor_id(); |
1569 | ||
1570 | #ifdef CONFIG_SMP | |
1571 | if (unlikely(task_running(rq, p))) | |
1572 | goto out_activate; | |
1573 | ||
e7693a36 | 1574 | new_cpu = p->sched_class->select_task_rq(p, sync); |
1da177e4 LT |
1575 | if (new_cpu != cpu) { |
1576 | set_task_cpu(p, new_cpu); | |
1577 | task_rq_unlock(rq, &flags); | |
1578 | /* might preempt at this point */ | |
1579 | rq = task_rq_lock(p, &flags); | |
1580 | old_state = p->state; | |
1581 | if (!(old_state & state)) | |
1582 | goto out; | |
dd41f596 | 1583 | if (p->se.on_rq) |
1da177e4 LT |
1584 | goto out_running; |
1585 | ||
1586 | this_cpu = smp_processor_id(); | |
1587 | cpu = task_cpu(p); | |
1588 | } | |
1589 | ||
e7693a36 GH |
1590 | #ifdef CONFIG_SCHEDSTATS |
1591 | schedstat_inc(rq, ttwu_count); | |
1592 | if (cpu == this_cpu) | |
1593 | schedstat_inc(rq, ttwu_local); | |
1594 | else { | |
1595 | struct sched_domain *sd; | |
1596 | for_each_domain(this_cpu, sd) { | |
1597 | if (cpu_isset(cpu, sd->span)) { | |
1598 | schedstat_inc(sd, ttwu_wake_remote); | |
1599 | break; | |
1600 | } | |
1601 | } | |
1602 | } | |
1603 | ||
1604 | #endif | |
1605 | ||
1606 | ||
1da177e4 LT |
1607 | out_activate: |
1608 | #endif /* CONFIG_SMP */ | |
cc367732 IM |
1609 | schedstat_inc(p, se.nr_wakeups); |
1610 | if (sync) | |
1611 | schedstat_inc(p, se.nr_wakeups_sync); | |
1612 | if (orig_cpu != cpu) | |
1613 | schedstat_inc(p, se.nr_wakeups_migrate); | |
1614 | if (cpu == this_cpu) | |
1615 | schedstat_inc(p, se.nr_wakeups_local); | |
1616 | else | |
1617 | schedstat_inc(p, se.nr_wakeups_remote); | |
2daa3577 | 1618 | update_rq_clock(rq); |
dd41f596 | 1619 | activate_task(rq, p, 1); |
9c63d9c0 | 1620 | check_preempt_curr(rq, p); |
1da177e4 LT |
1621 | success = 1; |
1622 | ||
1623 | out_running: | |
1624 | p->state = TASK_RUNNING; | |
4642dafd | 1625 | wakeup_balance_rt(rq, p); |
1da177e4 LT |
1626 | out: |
1627 | task_rq_unlock(rq, &flags); | |
1628 | ||
1629 | return success; | |
1630 | } | |
1631 | ||
36c8b586 | 1632 | int fastcall wake_up_process(struct task_struct *p) |
1da177e4 LT |
1633 | { |
1634 | return try_to_wake_up(p, TASK_STOPPED | TASK_TRACED | | |
1635 | TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE, 0); | |
1636 | } | |
1da177e4 LT |
1637 | EXPORT_SYMBOL(wake_up_process); |
1638 | ||
36c8b586 | 1639 | int fastcall wake_up_state(struct task_struct *p, unsigned int state) |
1da177e4 LT |
1640 | { |
1641 | return try_to_wake_up(p, state, 0); | |
1642 | } | |
1643 | ||
1da177e4 LT |
1644 | /* |
1645 | * Perform scheduler related setup for a newly forked process p. | |
1646 | * p is forked by current. | |
dd41f596 IM |
1647 | * |
1648 | * __sched_fork() is basic setup used by init_idle() too: | |
1649 | */ | |
1650 | static void __sched_fork(struct task_struct *p) | |
1651 | { | |
dd41f596 IM |
1652 | p->se.exec_start = 0; |
1653 | p->se.sum_exec_runtime = 0; | |
f6cf891c | 1654 | p->se.prev_sum_exec_runtime = 0; |
6cfb0d5d IM |
1655 | |
1656 | #ifdef CONFIG_SCHEDSTATS | |
1657 | p->se.wait_start = 0; | |
dd41f596 IM |
1658 | p->se.sum_sleep_runtime = 0; |
1659 | p->se.sleep_start = 0; | |
dd41f596 IM |
1660 | p->se.block_start = 0; |
1661 | p->se.sleep_max = 0; | |
1662 | p->se.block_max = 0; | |
1663 | p->se.exec_max = 0; | |
eba1ed4b | 1664 | p->se.slice_max = 0; |
dd41f596 | 1665 | p->se.wait_max = 0; |
6cfb0d5d | 1666 | #endif |
476d139c | 1667 | |
dd41f596 IM |
1668 | INIT_LIST_HEAD(&p->run_list); |
1669 | p->se.on_rq = 0; | |
476d139c | 1670 | |
e107be36 AK |
1671 | #ifdef CONFIG_PREEMPT_NOTIFIERS |
1672 | INIT_HLIST_HEAD(&p->preempt_notifiers); | |
1673 | #endif | |
1674 | ||
1da177e4 LT |
1675 | /* |
1676 | * We mark the process as running here, but have not actually | |
1677 | * inserted it onto the runqueue yet. This guarantees that | |
1678 | * nobody will actually run it, and a signal or other external | |
1679 | * event cannot wake it up and insert it on the runqueue either. | |
1680 | */ | |
1681 | p->state = TASK_RUNNING; | |
dd41f596 IM |
1682 | } |
1683 | ||
1684 | /* | |
1685 | * fork()/clone()-time setup: | |
1686 | */ | |
1687 | void sched_fork(struct task_struct *p, int clone_flags) | |
1688 | { | |
1689 | int cpu = get_cpu(); | |
1690 | ||
1691 | __sched_fork(p); | |
1692 | ||
1693 | #ifdef CONFIG_SMP | |
1694 | cpu = sched_balance_self(cpu, SD_BALANCE_FORK); | |
1695 | #endif | |
02e4bac2 | 1696 | set_task_cpu(p, cpu); |
b29739f9 IM |
1697 | |
1698 | /* | |
1699 | * Make sure we do not leak PI boosting priority to the child: | |
1700 | */ | |
1701 | p->prio = current->normal_prio; | |
2ddbf952 HS |
1702 | if (!rt_prio(p->prio)) |
1703 | p->sched_class = &fair_sched_class; | |
b29739f9 | 1704 | |
52f17b6c | 1705 | #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) |
dd41f596 | 1706 | if (likely(sched_info_on())) |
52f17b6c | 1707 | memset(&p->sched_info, 0, sizeof(p->sched_info)); |
1da177e4 | 1708 | #endif |
d6077cb8 | 1709 | #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW) |
4866cde0 NP |
1710 | p->oncpu = 0; |
1711 | #endif | |
1da177e4 | 1712 | #ifdef CONFIG_PREEMPT |
4866cde0 | 1713 | /* Want to start with kernel preemption disabled. */ |
a1261f54 | 1714 | task_thread_info(p)->preempt_count = 1; |
1da177e4 | 1715 | #endif |
476d139c | 1716 | put_cpu(); |
1da177e4 LT |
1717 | } |
1718 | ||
1719 | /* | |
1720 | * wake_up_new_task - wake up a newly created task for the first time. | |
1721 | * | |
1722 | * This function will do some initial scheduler statistics housekeeping | |
1723 | * that must be done for every newly created context, then puts the task | |
1724 | * on the runqueue and wakes it. | |
1725 | */ | |
36c8b586 | 1726 | void fastcall wake_up_new_task(struct task_struct *p, unsigned long clone_flags) |
1da177e4 LT |
1727 | { |
1728 | unsigned long flags; | |
dd41f596 | 1729 | struct rq *rq; |
1da177e4 LT |
1730 | |
1731 | rq = task_rq_lock(p, &flags); | |
147cbb4b | 1732 | BUG_ON(p->state != TASK_RUNNING); |
a8e504d2 | 1733 | update_rq_clock(rq); |
1da177e4 LT |
1734 | |
1735 | p->prio = effective_prio(p); | |
1736 | ||
b9dca1e0 | 1737 | if (!p->sched_class->task_new || !current->se.on_rq) { |
dd41f596 | 1738 | activate_task(rq, p, 0); |
1da177e4 | 1739 | } else { |
1da177e4 | 1740 | /* |
dd41f596 IM |
1741 | * Let the scheduling class do new task startup |
1742 | * management (if any): | |
1da177e4 | 1743 | */ |
ee0827d8 | 1744 | p->sched_class->task_new(rq, p); |
e5fa2237 | 1745 | inc_nr_running(p, rq); |
1da177e4 | 1746 | } |
dd41f596 | 1747 | check_preempt_curr(rq, p); |
0d1311a5 | 1748 | wakeup_balance_rt(rq, p); |
dd41f596 | 1749 | task_rq_unlock(rq, &flags); |
1da177e4 LT |
1750 | } |
1751 | ||
e107be36 AK |
1752 | #ifdef CONFIG_PREEMPT_NOTIFIERS |
1753 | ||
1754 | /** | |
421cee29 RD |
1755 | * preempt_notifier_register - tell me when current is being being preempted & rescheduled |
1756 | * @notifier: notifier struct to register | |
e107be36 AK |
1757 | */ |
1758 | void preempt_notifier_register(struct preempt_notifier *notifier) | |
1759 | { | |
1760 | hlist_add_head(¬ifier->link, ¤t->preempt_notifiers); | |
1761 | } | |
1762 | EXPORT_SYMBOL_GPL(preempt_notifier_register); | |
1763 | ||
1764 | /** | |
1765 | * preempt_notifier_unregister - no longer interested in preemption notifications | |
421cee29 | 1766 | * @notifier: notifier struct to unregister |
e107be36 AK |
1767 | * |
1768 | * This is safe to call from within a preemption notifier. | |
1769 | */ | |
1770 | void preempt_notifier_unregister(struct preempt_notifier *notifier) | |
1771 | { | |
1772 | hlist_del(¬ifier->link); | |
1773 | } | |
1774 | EXPORT_SYMBOL_GPL(preempt_notifier_unregister); | |
1775 | ||
1776 | static void fire_sched_in_preempt_notifiers(struct task_struct *curr) | |
1777 | { | |
1778 | struct preempt_notifier *notifier; | |
1779 | struct hlist_node *node; | |
1780 | ||
1781 | hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link) | |
1782 | notifier->ops->sched_in(notifier, raw_smp_processor_id()); | |
1783 | } | |
1784 | ||
1785 | static void | |
1786 | fire_sched_out_preempt_notifiers(struct task_struct *curr, | |
1787 | struct task_struct *next) | |
1788 | { | |
1789 | struct preempt_notifier *notifier; | |
1790 | struct hlist_node *node; | |
1791 | ||
1792 | hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link) | |
1793 | notifier->ops->sched_out(notifier, next); | |
1794 | } | |
1795 | ||
1796 | #else | |
1797 | ||
1798 | static void fire_sched_in_preempt_notifiers(struct task_struct *curr) | |
1799 | { | |
1800 | } | |
1801 | ||
1802 | static void | |
1803 | fire_sched_out_preempt_notifiers(struct task_struct *curr, | |
1804 | struct task_struct *next) | |
1805 | { | |
1806 | } | |
1807 | ||
1808 | #endif | |
1809 | ||
4866cde0 NP |
1810 | /** |
1811 | * prepare_task_switch - prepare to switch tasks | |
1812 | * @rq: the runqueue preparing to switch | |
421cee29 | 1813 | * @prev: the current task that is being switched out |
4866cde0 NP |
1814 | * @next: the task we are going to switch to. |
1815 | * | |
1816 | * This is called with the rq lock held and interrupts off. It must | |
1817 | * be paired with a subsequent finish_task_switch after the context | |
1818 | * switch. | |
1819 | * | |
1820 | * prepare_task_switch sets up locking and calls architecture specific | |
1821 | * hooks. | |
1822 | */ | |
e107be36 AK |
1823 | static inline void |
1824 | prepare_task_switch(struct rq *rq, struct task_struct *prev, | |
1825 | struct task_struct *next) | |
4866cde0 | 1826 | { |
e107be36 | 1827 | fire_sched_out_preempt_notifiers(prev, next); |
4866cde0 NP |
1828 | prepare_lock_switch(rq, next); |
1829 | prepare_arch_switch(next); | |
1830 | } | |
1831 | ||
1da177e4 LT |
1832 | /** |
1833 | * finish_task_switch - clean up after a task-switch | |
344babaa | 1834 | * @rq: runqueue associated with task-switch |
1da177e4 LT |
1835 | * @prev: the thread we just switched away from. |
1836 | * | |
4866cde0 NP |
1837 | * finish_task_switch must be called after the context switch, paired |
1838 | * with a prepare_task_switch call before the context switch. | |
1839 | * finish_task_switch will reconcile locking set up by prepare_task_switch, | |
1840 | * and do any other architecture-specific cleanup actions. | |
1da177e4 LT |
1841 | * |
1842 | * Note that we may have delayed dropping an mm in context_switch(). If | |
41a2d6cf | 1843 | * so, we finish that here outside of the runqueue lock. (Doing it |
1da177e4 LT |
1844 | * with the lock held can cause deadlocks; see schedule() for |
1845 | * details.) | |
1846 | */ | |
a9957449 | 1847 | static void finish_task_switch(struct rq *rq, struct task_struct *prev) |
1da177e4 LT |
1848 | __releases(rq->lock) |
1849 | { | |
1da177e4 | 1850 | struct mm_struct *mm = rq->prev_mm; |
55a101f8 | 1851 | long prev_state; |
1da177e4 LT |
1852 | |
1853 | rq->prev_mm = NULL; | |
1854 | ||
1855 | /* | |
1856 | * A task struct has one reference for the use as "current". | |
c394cc9f | 1857 | * If a task dies, then it sets TASK_DEAD in tsk->state and calls |
55a101f8 ON |
1858 | * schedule one last time. The schedule call will never return, and |
1859 | * the scheduled task must drop that reference. | |
c394cc9f | 1860 | * The test for TASK_DEAD must occur while the runqueue locks are |
1da177e4 LT |
1861 | * still held, otherwise prev could be scheduled on another cpu, die |
1862 | * there before we look at prev->state, and then the reference would | |
1863 | * be dropped twice. | |
1864 | * Manfred Spraul <manfred@colorfullife.com> | |
1865 | */ | |
55a101f8 | 1866 | prev_state = prev->state; |
4866cde0 NP |
1867 | finish_arch_switch(prev); |
1868 | finish_lock_switch(rq, prev); | |
e8fa1362 SR |
1869 | schedule_tail_balance_rt(rq); |
1870 | ||
e107be36 | 1871 | fire_sched_in_preempt_notifiers(current); |
1da177e4 LT |
1872 | if (mm) |
1873 | mmdrop(mm); | |
c394cc9f | 1874 | if (unlikely(prev_state == TASK_DEAD)) { |
c6fd91f0 | 1875 | /* |
1876 | * Remove function-return probe instances associated with this | |
1877 | * task and put them back on the free list. | |
9761eea8 | 1878 | */ |
c6fd91f0 | 1879 | kprobe_flush_task(prev); |
1da177e4 | 1880 | put_task_struct(prev); |
c6fd91f0 | 1881 | } |
1da177e4 LT |
1882 | } |
1883 | ||
1884 | /** | |
1885 | * schedule_tail - first thing a freshly forked thread must call. | |
1886 | * @prev: the thread we just switched away from. | |
1887 | */ | |
36c8b586 | 1888 | asmlinkage void schedule_tail(struct task_struct *prev) |
1da177e4 LT |
1889 | __releases(rq->lock) |
1890 | { | |
70b97a7f IM |
1891 | struct rq *rq = this_rq(); |
1892 | ||
4866cde0 NP |
1893 | finish_task_switch(rq, prev); |
1894 | #ifdef __ARCH_WANT_UNLOCKED_CTXSW | |
1895 | /* In this case, finish_task_switch does not reenable preemption */ | |
1896 | preempt_enable(); | |
1897 | #endif | |
1da177e4 | 1898 | if (current->set_child_tid) |
b488893a | 1899 | put_user(task_pid_vnr(current), current->set_child_tid); |
1da177e4 LT |
1900 | } |
1901 | ||
1902 | /* | |
1903 | * context_switch - switch to the new MM and the new | |
1904 | * thread's register state. | |
1905 | */ | |
dd41f596 | 1906 | static inline void |
70b97a7f | 1907 | context_switch(struct rq *rq, struct task_struct *prev, |
36c8b586 | 1908 | struct task_struct *next) |
1da177e4 | 1909 | { |
dd41f596 | 1910 | struct mm_struct *mm, *oldmm; |
1da177e4 | 1911 | |
e107be36 | 1912 | prepare_task_switch(rq, prev, next); |
dd41f596 IM |
1913 | mm = next->mm; |
1914 | oldmm = prev->active_mm; | |
9226d125 ZA |
1915 | /* |
1916 | * For paravirt, this is coupled with an exit in switch_to to | |
1917 | * combine the page table reload and the switch backend into | |
1918 | * one hypercall. | |
1919 | */ | |
1920 | arch_enter_lazy_cpu_mode(); | |
1921 | ||
dd41f596 | 1922 | if (unlikely(!mm)) { |
1da177e4 LT |
1923 | next->active_mm = oldmm; |
1924 | atomic_inc(&oldmm->mm_count); | |
1925 | enter_lazy_tlb(oldmm, next); | |
1926 | } else | |
1927 | switch_mm(oldmm, mm, next); | |
1928 | ||
dd41f596 | 1929 | if (unlikely(!prev->mm)) { |
1da177e4 | 1930 | prev->active_mm = NULL; |
1da177e4 LT |
1931 | rq->prev_mm = oldmm; |
1932 | } | |
3a5f5e48 IM |
1933 | /* |
1934 | * Since the runqueue lock will be released by the next | |
1935 | * task (which is an invalid locking op but in the case | |
1936 | * of the scheduler it's an obvious special-case), so we | |
1937 | * do an early lockdep release here: | |
1938 | */ | |
1939 | #ifndef __ARCH_WANT_UNLOCKED_CTXSW | |
8a25d5de | 1940 | spin_release(&rq->lock.dep_map, 1, _THIS_IP_); |
3a5f5e48 | 1941 | #endif |
1da177e4 LT |
1942 | |
1943 | /* Here we just switch the register state and the stack. */ | |
1944 | switch_to(prev, next, prev); | |
1945 | ||
dd41f596 IM |
1946 | barrier(); |
1947 | /* | |
1948 | * this_rq must be evaluated again because prev may have moved | |
1949 | * CPUs since it called schedule(), thus the 'rq' on its stack | |
1950 | * frame will be invalid. | |
1951 | */ | |
1952 | finish_task_switch(this_rq(), prev); | |
1da177e4 LT |
1953 | } |
1954 | ||
1955 | /* | |
1956 | * nr_running, nr_uninterruptible and nr_context_switches: | |
1957 | * | |
1958 | * externally visible scheduler statistics: current number of runnable | |
1959 | * threads, current number of uninterruptible-sleeping threads, total | |
1960 | * number of context switches performed since bootup. | |
1961 | */ | |
1962 | unsigned long nr_running(void) | |
1963 | { | |
1964 | unsigned long i, sum = 0; | |
1965 | ||
1966 | for_each_online_cpu(i) | |
1967 | sum += cpu_rq(i)->nr_running; | |
1968 | ||
1969 | return sum; | |
1970 | } | |
1971 | ||
1972 | unsigned long nr_uninterruptible(void) | |
1973 | { | |
1974 | unsigned long i, sum = 0; | |
1975 | ||
0a945022 | 1976 | for_each_possible_cpu(i) |
1da177e4 LT |
1977 | sum += cpu_rq(i)->nr_uninterruptible; |
1978 | ||
1979 | /* | |
1980 | * Since we read the counters lockless, it might be slightly | |
1981 | * inaccurate. Do not allow it to go below zero though: | |
1982 | */ | |
1983 | if (unlikely((long)sum < 0)) | |
1984 | sum = 0; | |
1985 | ||
1986 | return sum; | |
1987 | } | |
1988 | ||
1989 | unsigned long long nr_context_switches(void) | |
1990 | { | |
cc94abfc SR |
1991 | int i; |
1992 | unsigned long long sum = 0; | |
1da177e4 | 1993 | |
0a945022 | 1994 | for_each_possible_cpu(i) |
1da177e4 LT |
1995 | sum += cpu_rq(i)->nr_switches; |
1996 | ||
1997 | return sum; | |
1998 | } | |
1999 | ||
2000 | unsigned long nr_iowait(void) | |
2001 | { | |
2002 | unsigned long i, sum = 0; | |
2003 | ||
0a945022 | 2004 | for_each_possible_cpu(i) |
1da177e4 LT |
2005 | sum += atomic_read(&cpu_rq(i)->nr_iowait); |
2006 | ||
2007 | return sum; | |
2008 | } | |
2009 | ||
db1b1fef JS |
2010 | unsigned long nr_active(void) |
2011 | { | |
2012 | unsigned long i, running = 0, uninterruptible = 0; | |
2013 | ||
2014 | for_each_online_cpu(i) { | |
2015 | running += cpu_rq(i)->nr_running; | |
2016 | uninterruptible += cpu_rq(i)->nr_uninterruptible; | |
2017 | } | |
2018 | ||
2019 | if (unlikely((long)uninterruptible < 0)) | |
2020 | uninterruptible = 0; | |
2021 | ||
2022 | return running + uninterruptible; | |
2023 | } | |
2024 | ||
48f24c4d | 2025 | /* |
dd41f596 IM |
2026 | * Update rq->cpu_load[] statistics. This function is usually called every |
2027 | * scheduler tick (TICK_NSEC). | |
48f24c4d | 2028 | */ |
dd41f596 | 2029 | static void update_cpu_load(struct rq *this_rq) |
48f24c4d | 2030 | { |
495eca49 | 2031 | unsigned long this_load = this_rq->load.weight; |
dd41f596 IM |
2032 | int i, scale; |
2033 | ||
2034 | this_rq->nr_load_updates++; | |
dd41f596 IM |
2035 | |
2036 | /* Update our load: */ | |
2037 | for (i = 0, scale = 1; i < CPU_LOAD_IDX_MAX; i++, scale += scale) { | |
2038 | unsigned long old_load, new_load; | |
2039 | ||
2040 | /* scale is effectively 1 << i now, and >> i divides by scale */ | |
2041 | ||
2042 | old_load = this_rq->cpu_load[i]; | |
2043 | new_load = this_load; | |
a25707f3 IM |
2044 | /* |
2045 | * Round up the averaging division if load is increasing. This | |
2046 | * prevents us from getting stuck on 9 if the load is 10, for | |
2047 | * example. | |
2048 | */ | |
2049 | if (new_load > old_load) | |
2050 | new_load += scale-1; | |
dd41f596 IM |
2051 | this_rq->cpu_load[i] = (old_load*(scale-1) + new_load) >> i; |
2052 | } | |
48f24c4d IM |
2053 | } |
2054 | ||
dd41f596 IM |
2055 | #ifdef CONFIG_SMP |
2056 | ||
1da177e4 LT |
2057 | /* |
2058 | * double_rq_lock - safely lock two runqueues | |
2059 | * | |
2060 | * Note this does not disable interrupts like task_rq_lock, | |
2061 | * you need to do so manually before calling. | |
2062 | */ | |
70b97a7f | 2063 | static void double_rq_lock(struct rq *rq1, struct rq *rq2) |
1da177e4 LT |
2064 | __acquires(rq1->lock) |
2065 | __acquires(rq2->lock) | |
2066 | { | |
054b9108 | 2067 | BUG_ON(!irqs_disabled()); |
1da177e4 LT |
2068 | if (rq1 == rq2) { |
2069 | spin_lock(&rq1->lock); | |
2070 | __acquire(rq2->lock); /* Fake it out ;) */ | |
2071 | } else { | |
c96d145e | 2072 | if (rq1 < rq2) { |
1da177e4 LT |
2073 | spin_lock(&rq1->lock); |
2074 | spin_lock(&rq2->lock); | |
2075 | } else { | |
2076 | spin_lock(&rq2->lock); | |
2077 | spin_lock(&rq1->lock); | |
2078 | } | |
2079 | } | |
6e82a3be IM |
2080 | update_rq_clock(rq1); |
2081 | update_rq_clock(rq2); | |
1da177e4 LT |
2082 | } |
2083 | ||
2084 | /* | |
2085 | * double_rq_unlock - safely unlock two runqueues | |
2086 | * | |
2087 | * Note this does not restore interrupts like task_rq_unlock, | |
2088 | * you need to do so manually after calling. | |
2089 | */ | |
70b97a7f | 2090 | static void double_rq_unlock(struct rq *rq1, struct rq *rq2) |
1da177e4 LT |
2091 | __releases(rq1->lock) |
2092 | __releases(rq2->lock) | |
2093 | { | |
2094 | spin_unlock(&rq1->lock); | |
2095 | if (rq1 != rq2) | |
2096 | spin_unlock(&rq2->lock); | |
2097 | else | |
2098 | __release(rq2->lock); | |
2099 | } | |
2100 | ||
2101 | /* | |
2102 | * double_lock_balance - lock the busiest runqueue, this_rq is locked already. | |
2103 | */ | |
e8fa1362 | 2104 | static int double_lock_balance(struct rq *this_rq, struct rq *busiest) |
1da177e4 LT |
2105 | __releases(this_rq->lock) |
2106 | __acquires(busiest->lock) | |
2107 | __acquires(this_rq->lock) | |
2108 | { | |
e8fa1362 SR |
2109 | int ret = 0; |
2110 | ||
054b9108 KK |
2111 | if (unlikely(!irqs_disabled())) { |
2112 | /* printk() doesn't work good under rq->lock */ | |
2113 | spin_unlock(&this_rq->lock); | |
2114 | BUG_ON(1); | |
2115 | } | |
1da177e4 | 2116 | if (unlikely(!spin_trylock(&busiest->lock))) { |
c96d145e | 2117 | if (busiest < this_rq) { |
1da177e4 LT |
2118 | spin_unlock(&this_rq->lock); |
2119 | spin_lock(&busiest->lock); | |
2120 | spin_lock(&this_rq->lock); | |
e8fa1362 | 2121 | ret = 1; |
1da177e4 LT |
2122 | } else |
2123 | spin_lock(&busiest->lock); | |
2124 | } | |
e8fa1362 | 2125 | return ret; |
1da177e4 LT |
2126 | } |
2127 | ||
1da177e4 LT |
2128 | /* |
2129 | * If dest_cpu is allowed for this process, migrate the task to it. | |
2130 | * This is accomplished by forcing the cpu_allowed mask to only | |
41a2d6cf | 2131 | * allow dest_cpu, which will force the cpu onto dest_cpu. Then |
1da177e4 LT |
2132 | * the cpu_allowed mask is restored. |
2133 | */ | |
36c8b586 | 2134 | static void sched_migrate_task(struct task_struct *p, int dest_cpu) |
1da177e4 | 2135 | { |
70b97a7f | 2136 | struct migration_req req; |
1da177e4 | 2137 | unsigned long flags; |
70b97a7f | 2138 | struct rq *rq; |
1da177e4 LT |
2139 | |
2140 | rq = task_rq_lock(p, &flags); | |
2141 | if (!cpu_isset(dest_cpu, p->cpus_allowed) | |
2142 | || unlikely(cpu_is_offline(dest_cpu))) | |
2143 | goto out; | |
2144 | ||
2145 | /* force the process onto the specified CPU */ | |
2146 | if (migrate_task(p, dest_cpu, &req)) { | |
2147 | /* Need to wait for migration thread (might exit: take ref). */ | |
2148 | struct task_struct *mt = rq->migration_thread; | |
36c8b586 | 2149 | |
1da177e4 LT |
2150 | get_task_struct(mt); |
2151 | task_rq_unlock(rq, &flags); | |
2152 | wake_up_process(mt); | |
2153 | put_task_struct(mt); | |
2154 | wait_for_completion(&req.done); | |
36c8b586 | 2155 | |
1da177e4 LT |
2156 | return; |
2157 | } | |
2158 | out: | |
2159 | task_rq_unlock(rq, &flags); | |
2160 | } | |
2161 | ||
2162 | /* | |
476d139c NP |
2163 | * sched_exec - execve() is a valuable balancing opportunity, because at |
2164 | * this point the task has the smallest effective memory and cache footprint. | |
1da177e4 LT |
2165 | */ |
2166 | void sched_exec(void) | |
2167 | { | |
1da177e4 | 2168 | int new_cpu, this_cpu = get_cpu(); |
476d139c | 2169 | new_cpu = sched_balance_self(this_cpu, SD_BALANCE_EXEC); |
1da177e4 | 2170 | put_cpu(); |
476d139c NP |
2171 | if (new_cpu != this_cpu) |
2172 | sched_migrate_task(current, new_cpu); | |
1da177e4 LT |
2173 | } |
2174 | ||
2175 | /* | |
2176 | * pull_task - move a task from a remote runqueue to the local runqueue. | |
2177 | * Both runqueues must be locked. | |
2178 | */ | |
dd41f596 IM |
2179 | static void pull_task(struct rq *src_rq, struct task_struct *p, |
2180 | struct rq *this_rq, int this_cpu) | |
1da177e4 | 2181 | { |
2e1cb74a | 2182 | deactivate_task(src_rq, p, 0); |
1da177e4 | 2183 | set_task_cpu(p, this_cpu); |
dd41f596 | 2184 | activate_task(this_rq, p, 0); |
1da177e4 LT |
2185 | /* |
2186 | * Note that idle threads have a prio of MAX_PRIO, for this test | |
2187 | * to be always true for them. | |
2188 | */ | |
dd41f596 | 2189 | check_preempt_curr(this_rq, p); |
1da177e4 LT |
2190 | } |
2191 | ||
2192 | /* | |
2193 | * can_migrate_task - may task p from runqueue rq be migrated to this_cpu? | |
2194 | */ | |
858119e1 | 2195 | static |
70b97a7f | 2196 | int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu, |
d15bcfdb | 2197 | struct sched_domain *sd, enum cpu_idle_type idle, |
95cdf3b7 | 2198 | int *all_pinned) |
1da177e4 LT |
2199 | { |
2200 | /* | |
2201 | * We do not migrate tasks that are: | |
2202 | * 1) running (obviously), or | |
2203 | * 2) cannot be migrated to this CPU due to cpus_allowed, or | |
2204 | * 3) are cache-hot on their current CPU. | |
2205 | */ | |
cc367732 IM |
2206 | if (!cpu_isset(this_cpu, p->cpus_allowed)) { |
2207 | schedstat_inc(p, se.nr_failed_migrations_affine); | |
1da177e4 | 2208 | return 0; |
cc367732 | 2209 | } |
81026794 NP |
2210 | *all_pinned = 0; |
2211 | ||
cc367732 IM |
2212 | if (task_running(rq, p)) { |
2213 | schedstat_inc(p, se.nr_failed_migrations_running); | |
81026794 | 2214 | return 0; |
cc367732 | 2215 | } |
1da177e4 | 2216 | |
da84d961 IM |
2217 | /* |
2218 | * Aggressive migration if: | |
2219 | * 1) task is cache cold, or | |
2220 | * 2) too many balance attempts have failed. | |
2221 | */ | |
2222 | ||
6bc1665b IM |
2223 | if (!task_hot(p, rq->clock, sd) || |
2224 | sd->nr_balance_failed > sd->cache_nice_tries) { | |
da84d961 | 2225 | #ifdef CONFIG_SCHEDSTATS |
cc367732 | 2226 | if (task_hot(p, rq->clock, sd)) { |
da84d961 | 2227 | schedstat_inc(sd, lb_hot_gained[idle]); |
cc367732 IM |
2228 | schedstat_inc(p, se.nr_forced_migrations); |
2229 | } | |
da84d961 IM |
2230 | #endif |
2231 | return 1; | |
2232 | } | |
2233 | ||
cc367732 IM |
2234 | if (task_hot(p, rq->clock, sd)) { |
2235 | schedstat_inc(p, se.nr_failed_migrations_hot); | |
da84d961 | 2236 | return 0; |
cc367732 | 2237 | } |
1da177e4 LT |
2238 | return 1; |
2239 | } | |
2240 | ||
e1d1484f PW |
2241 | static unsigned long |
2242 | balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
2243 | unsigned long max_load_move, struct sched_domain *sd, | |
2244 | enum cpu_idle_type idle, int *all_pinned, | |
2245 | int *this_best_prio, struct rq_iterator *iterator) | |
1da177e4 | 2246 | { |
b82d9fdd | 2247 | int loops = 0, pulled = 0, pinned = 0, skip_for_load; |
dd41f596 IM |
2248 | struct task_struct *p; |
2249 | long rem_load_move = max_load_move; | |
1da177e4 | 2250 | |
e1d1484f | 2251 | if (max_load_move == 0) |
1da177e4 LT |
2252 | goto out; |
2253 | ||
81026794 NP |
2254 | pinned = 1; |
2255 | ||
1da177e4 | 2256 | /* |
dd41f596 | 2257 | * Start the load-balancing iterator: |
1da177e4 | 2258 | */ |
dd41f596 IM |
2259 | p = iterator->start(iterator->arg); |
2260 | next: | |
b82d9fdd | 2261 | if (!p || loops++ > sysctl_sched_nr_migrate) |
1da177e4 | 2262 | goto out; |
50ddd969 | 2263 | /* |
b82d9fdd | 2264 | * To help distribute high priority tasks across CPUs we don't |
50ddd969 PW |
2265 | * skip a task if it will be the highest priority task (i.e. smallest |
2266 | * prio value) on its new queue regardless of its load weight | |
2267 | */ | |
dd41f596 IM |
2268 | skip_for_load = (p->se.load.weight >> 1) > rem_load_move + |
2269 | SCHED_LOAD_SCALE_FUZZ; | |
a4ac01c3 | 2270 | if ((skip_for_load && p->prio >= *this_best_prio) || |
dd41f596 | 2271 | !can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) { |
dd41f596 IM |
2272 | p = iterator->next(iterator->arg); |
2273 | goto next; | |
1da177e4 LT |
2274 | } |
2275 | ||
dd41f596 | 2276 | pull_task(busiest, p, this_rq, this_cpu); |
1da177e4 | 2277 | pulled++; |
dd41f596 | 2278 | rem_load_move -= p->se.load.weight; |
1da177e4 | 2279 | |
2dd73a4f | 2280 | /* |
b82d9fdd | 2281 | * We only want to steal up to the prescribed amount of weighted load. |
2dd73a4f | 2282 | */ |
e1d1484f | 2283 | if (rem_load_move > 0) { |
a4ac01c3 PW |
2284 | if (p->prio < *this_best_prio) |
2285 | *this_best_prio = p->prio; | |
dd41f596 IM |
2286 | p = iterator->next(iterator->arg); |
2287 | goto next; | |
1da177e4 LT |
2288 | } |
2289 | out: | |
2290 | /* | |
e1d1484f | 2291 | * Right now, this is one of only two places pull_task() is called, |
1da177e4 LT |
2292 | * so we can safely collect pull_task() stats here rather than |
2293 | * inside pull_task(). | |
2294 | */ | |
2295 | schedstat_add(sd, lb_gained[idle], pulled); | |
81026794 NP |
2296 | |
2297 | if (all_pinned) | |
2298 | *all_pinned = pinned; | |
e1d1484f PW |
2299 | |
2300 | return max_load_move - rem_load_move; | |
1da177e4 LT |
2301 | } |
2302 | ||
dd41f596 | 2303 | /* |
43010659 PW |
2304 | * move_tasks tries to move up to max_load_move weighted load from busiest to |
2305 | * this_rq, as part of a balancing operation within domain "sd". | |
2306 | * Returns 1 if successful and 0 otherwise. | |
dd41f596 IM |
2307 | * |
2308 | * Called with both runqueues locked. | |
2309 | */ | |
2310 | static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
43010659 | 2311 | unsigned long max_load_move, |
dd41f596 IM |
2312 | struct sched_domain *sd, enum cpu_idle_type idle, |
2313 | int *all_pinned) | |
2314 | { | |
5522d5d5 | 2315 | const struct sched_class *class = sched_class_highest; |
43010659 | 2316 | unsigned long total_load_moved = 0; |
a4ac01c3 | 2317 | int this_best_prio = this_rq->curr->prio; |
dd41f596 IM |
2318 | |
2319 | do { | |
43010659 PW |
2320 | total_load_moved += |
2321 | class->load_balance(this_rq, this_cpu, busiest, | |
e1d1484f | 2322 | max_load_move - total_load_moved, |
a4ac01c3 | 2323 | sd, idle, all_pinned, &this_best_prio); |
dd41f596 | 2324 | class = class->next; |
43010659 | 2325 | } while (class && max_load_move > total_load_moved); |
dd41f596 | 2326 | |
43010659 PW |
2327 | return total_load_moved > 0; |
2328 | } | |
2329 | ||
e1d1484f PW |
2330 | static int |
2331 | iter_move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
2332 | struct sched_domain *sd, enum cpu_idle_type idle, | |
2333 | struct rq_iterator *iterator) | |
2334 | { | |
2335 | struct task_struct *p = iterator->start(iterator->arg); | |
2336 | int pinned = 0; | |
2337 | ||
2338 | while (p) { | |
2339 | if (can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) { | |
2340 | pull_task(busiest, p, this_rq, this_cpu); | |
2341 | /* | |
2342 | * Right now, this is only the second place pull_task() | |
2343 | * is called, so we can safely collect pull_task() | |
2344 | * stats here rather than inside pull_task(). | |
2345 | */ | |
2346 | schedstat_inc(sd, lb_gained[idle]); | |
2347 | ||
2348 | return 1; | |
2349 | } | |
2350 | p = iterator->next(iterator->arg); | |
2351 | } | |
2352 | ||
2353 | return 0; | |
2354 | } | |
2355 | ||
43010659 PW |
2356 | /* |
2357 | * move_one_task tries to move exactly one task from busiest to this_rq, as | |
2358 | * part of active balancing operations within "domain". | |
2359 | * Returns 1 if successful and 0 otherwise. | |
2360 | * | |
2361 | * Called with both runqueues locked. | |
2362 | */ | |
2363 | static int move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
2364 | struct sched_domain *sd, enum cpu_idle_type idle) | |
2365 | { | |
5522d5d5 | 2366 | const struct sched_class *class; |
43010659 PW |
2367 | |
2368 | for (class = sched_class_highest; class; class = class->next) | |
e1d1484f | 2369 | if (class->move_one_task(this_rq, this_cpu, busiest, sd, idle)) |
43010659 PW |
2370 | return 1; |
2371 | ||
2372 | return 0; | |
dd41f596 IM |
2373 | } |
2374 | ||
1da177e4 LT |
2375 | /* |
2376 | * find_busiest_group finds and returns the busiest CPU group within the | |
48f24c4d IM |
2377 | * domain. It calculates and returns the amount of weighted load which |
2378 | * should be moved to restore balance via the imbalance parameter. | |
1da177e4 LT |
2379 | */ |
2380 | static struct sched_group * | |
2381 | find_busiest_group(struct sched_domain *sd, int this_cpu, | |
dd41f596 IM |
2382 | unsigned long *imbalance, enum cpu_idle_type idle, |
2383 | int *sd_idle, cpumask_t *cpus, int *balance) | |
1da177e4 LT |
2384 | { |
2385 | struct sched_group *busiest = NULL, *this = NULL, *group = sd->groups; | |
2386 | unsigned long max_load, avg_load, total_load, this_load, total_pwr; | |
0c117f1b | 2387 | unsigned long max_pull; |
2dd73a4f PW |
2388 | unsigned long busiest_load_per_task, busiest_nr_running; |
2389 | unsigned long this_load_per_task, this_nr_running; | |
908a7c1b | 2390 | int load_idx, group_imb = 0; |
5c45bf27 SS |
2391 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) |
2392 | int power_savings_balance = 1; | |
2393 | unsigned long leader_nr_running = 0, min_load_per_task = 0; | |
2394 | unsigned long min_nr_running = ULONG_MAX; | |
2395 | struct sched_group *group_min = NULL, *group_leader = NULL; | |
2396 | #endif | |
1da177e4 LT |
2397 | |
2398 | max_load = this_load = total_load = total_pwr = 0; | |
2dd73a4f PW |
2399 | busiest_load_per_task = busiest_nr_running = 0; |
2400 | this_load_per_task = this_nr_running = 0; | |
d15bcfdb | 2401 | if (idle == CPU_NOT_IDLE) |
7897986b | 2402 | load_idx = sd->busy_idx; |
d15bcfdb | 2403 | else if (idle == CPU_NEWLY_IDLE) |
7897986b NP |
2404 | load_idx = sd->newidle_idx; |
2405 | else | |
2406 | load_idx = sd->idle_idx; | |
1da177e4 LT |
2407 | |
2408 | do { | |
908a7c1b | 2409 | unsigned long load, group_capacity, max_cpu_load, min_cpu_load; |
1da177e4 LT |
2410 | int local_group; |
2411 | int i; | |
908a7c1b | 2412 | int __group_imb = 0; |
783609c6 | 2413 | unsigned int balance_cpu = -1, first_idle_cpu = 0; |
2dd73a4f | 2414 | unsigned long sum_nr_running, sum_weighted_load; |
1da177e4 LT |
2415 | |
2416 | local_group = cpu_isset(this_cpu, group->cpumask); | |
2417 | ||
783609c6 SS |
2418 | if (local_group) |
2419 | balance_cpu = first_cpu(group->cpumask); | |
2420 | ||
1da177e4 | 2421 | /* Tally up the load of all CPUs in the group */ |
2dd73a4f | 2422 | sum_weighted_load = sum_nr_running = avg_load = 0; |
908a7c1b KC |
2423 | max_cpu_load = 0; |
2424 | min_cpu_load = ~0UL; | |
1da177e4 LT |
2425 | |
2426 | for_each_cpu_mask(i, group->cpumask) { | |
0a2966b4 CL |
2427 | struct rq *rq; |
2428 | ||
2429 | if (!cpu_isset(i, *cpus)) | |
2430 | continue; | |
2431 | ||
2432 | rq = cpu_rq(i); | |
2dd73a4f | 2433 | |
9439aab8 | 2434 | if (*sd_idle && rq->nr_running) |
5969fe06 NP |
2435 | *sd_idle = 0; |
2436 | ||
1da177e4 | 2437 | /* Bias balancing toward cpus of our domain */ |
783609c6 SS |
2438 | if (local_group) { |
2439 | if (idle_cpu(i) && !first_idle_cpu) { | |
2440 | first_idle_cpu = 1; | |
2441 | balance_cpu = i; | |
2442 | } | |
2443 | ||
a2000572 | 2444 | load = target_load(i, load_idx); |
908a7c1b | 2445 | } else { |
a2000572 | 2446 | load = source_load(i, load_idx); |
908a7c1b KC |
2447 | if (load > max_cpu_load) |
2448 | max_cpu_load = load; | |
2449 | if (min_cpu_load > load) | |
2450 | min_cpu_load = load; | |
2451 | } | |
1da177e4 LT |
2452 | |
2453 | avg_load += load; | |
2dd73a4f | 2454 | sum_nr_running += rq->nr_running; |
dd41f596 | 2455 | sum_weighted_load += weighted_cpuload(i); |
1da177e4 LT |
2456 | } |
2457 | ||
783609c6 SS |
2458 | /* |
2459 | * First idle cpu or the first cpu(busiest) in this sched group | |
2460 | * is eligible for doing load balancing at this and above | |
9439aab8 SS |
2461 | * domains. In the newly idle case, we will allow all the cpu's |
2462 | * to do the newly idle load balance. | |
783609c6 | 2463 | */ |
9439aab8 SS |
2464 | if (idle != CPU_NEWLY_IDLE && local_group && |
2465 | balance_cpu != this_cpu && balance) { | |
783609c6 SS |
2466 | *balance = 0; |
2467 | goto ret; | |
2468 | } | |
2469 | ||
1da177e4 | 2470 | total_load += avg_load; |
5517d86b | 2471 | total_pwr += group->__cpu_power; |
1da177e4 LT |
2472 | |
2473 | /* Adjust by relative CPU power of the group */ | |
5517d86b ED |
2474 | avg_load = sg_div_cpu_power(group, |
2475 | avg_load * SCHED_LOAD_SCALE); | |
1da177e4 | 2476 | |
908a7c1b KC |
2477 | if ((max_cpu_load - min_cpu_load) > SCHED_LOAD_SCALE) |
2478 | __group_imb = 1; | |
2479 | ||
5517d86b | 2480 | group_capacity = group->__cpu_power / SCHED_LOAD_SCALE; |
5c45bf27 | 2481 | |
1da177e4 LT |
2482 | if (local_group) { |
2483 | this_load = avg_load; | |
2484 | this = group; | |
2dd73a4f PW |
2485 | this_nr_running = sum_nr_running; |
2486 | this_load_per_task = sum_weighted_load; | |
2487 | } else if (avg_load > max_load && | |
908a7c1b | 2488 | (sum_nr_running > group_capacity || __group_imb)) { |
1da177e4 LT |
2489 | max_load = avg_load; |
2490 | busiest = group; | |
2dd73a4f PW |
2491 | busiest_nr_running = sum_nr_running; |
2492 | busiest_load_per_task = sum_weighted_load; | |
908a7c1b | 2493 | group_imb = __group_imb; |
1da177e4 | 2494 | } |
5c45bf27 SS |
2495 | |
2496 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) | |
2497 | /* | |
2498 | * Busy processors will not participate in power savings | |
2499 | * balance. | |
2500 | */ | |
dd41f596 IM |
2501 | if (idle == CPU_NOT_IDLE || |
2502 | !(sd->flags & SD_POWERSAVINGS_BALANCE)) | |
2503 | goto group_next; | |
5c45bf27 SS |
2504 | |
2505 | /* | |
2506 | * If the local group is idle or completely loaded | |
2507 | * no need to do power savings balance at this domain | |
2508 | */ | |
2509 | if (local_group && (this_nr_running >= group_capacity || | |
2510 | !this_nr_running)) | |
2511 | power_savings_balance = 0; | |
2512 | ||
dd41f596 | 2513 | /* |
5c45bf27 SS |
2514 | * If a group is already running at full capacity or idle, |
2515 | * don't include that group in power savings calculations | |
dd41f596 IM |
2516 | */ |
2517 | if (!power_savings_balance || sum_nr_running >= group_capacity | |
5c45bf27 | 2518 | || !sum_nr_running) |
dd41f596 | 2519 | goto group_next; |
5c45bf27 | 2520 | |
dd41f596 | 2521 | /* |
5c45bf27 | 2522 | * Calculate the group which has the least non-idle load. |
dd41f596 IM |
2523 | * This is the group from where we need to pick up the load |
2524 | * for saving power | |
2525 | */ | |
2526 | if ((sum_nr_running < min_nr_running) || | |
2527 | (sum_nr_running == min_nr_running && | |
5c45bf27 SS |
2528 | first_cpu(group->cpumask) < |
2529 | first_cpu(group_min->cpumask))) { | |
dd41f596 IM |
2530 | group_min = group; |
2531 | min_nr_running = sum_nr_running; | |
5c45bf27 SS |
2532 | min_load_per_task = sum_weighted_load / |
2533 | sum_nr_running; | |
dd41f596 | 2534 | } |
5c45bf27 | 2535 | |
dd41f596 | 2536 | /* |
5c45bf27 | 2537 | * Calculate the group which is almost near its |
dd41f596 IM |
2538 | * capacity but still has some space to pick up some load |
2539 | * from other group and save more power | |
2540 | */ | |
2541 | if (sum_nr_running <= group_capacity - 1) { | |
2542 | if (sum_nr_running > leader_nr_running || | |
2543 | (sum_nr_running == leader_nr_running && | |
2544 | first_cpu(group->cpumask) > | |
2545 | first_cpu(group_leader->cpumask))) { | |
2546 | group_leader = group; | |
2547 | leader_nr_running = sum_nr_running; | |
2548 | } | |
48f24c4d | 2549 | } |
5c45bf27 SS |
2550 | group_next: |
2551 | #endif | |
1da177e4 LT |
2552 | group = group->next; |
2553 | } while (group != sd->groups); | |
2554 | ||
2dd73a4f | 2555 | if (!busiest || this_load >= max_load || busiest_nr_running == 0) |
1da177e4 LT |
2556 | goto out_balanced; |
2557 | ||
2558 | avg_load = (SCHED_LOAD_SCALE * total_load) / total_pwr; | |
2559 | ||
2560 | if (this_load >= avg_load || | |
2561 | 100*max_load <= sd->imbalance_pct*this_load) | |
2562 | goto out_balanced; | |
2563 | ||
2dd73a4f | 2564 | busiest_load_per_task /= busiest_nr_running; |
908a7c1b KC |
2565 | if (group_imb) |
2566 | busiest_load_per_task = min(busiest_load_per_task, avg_load); | |
2567 | ||
1da177e4 LT |
2568 | /* |
2569 | * We're trying to get all the cpus to the average_load, so we don't | |
2570 | * want to push ourselves above the average load, nor do we wish to | |
2571 | * reduce the max loaded cpu below the average load, as either of these | |
2572 | * actions would just result in more rebalancing later, and ping-pong | |
2573 | * tasks around. Thus we look for the minimum possible imbalance. | |
2574 | * Negative imbalances (*we* are more loaded than anyone else) will | |
2575 | * be counted as no imbalance for these purposes -- we can't fix that | |
41a2d6cf | 2576 | * by pulling tasks to us. Be careful of negative numbers as they'll |
1da177e4 LT |
2577 | * appear as very large values with unsigned longs. |
2578 | */ | |
2dd73a4f PW |
2579 | if (max_load <= busiest_load_per_task) |
2580 | goto out_balanced; | |
2581 | ||
2582 | /* | |
2583 | * In the presence of smp nice balancing, certain scenarios can have | |
2584 | * max load less than avg load(as we skip the groups at or below | |
2585 | * its cpu_power, while calculating max_load..) | |
2586 | */ | |
2587 | if (max_load < avg_load) { | |
2588 | *imbalance = 0; | |
2589 | goto small_imbalance; | |
2590 | } | |
0c117f1b SS |
2591 | |
2592 | /* Don't want to pull so many tasks that a group would go idle */ | |
2dd73a4f | 2593 | max_pull = min(max_load - avg_load, max_load - busiest_load_per_task); |
0c117f1b | 2594 | |
1da177e4 | 2595 | /* How much load to actually move to equalise the imbalance */ |
5517d86b ED |
2596 | *imbalance = min(max_pull * busiest->__cpu_power, |
2597 | (avg_load - this_load) * this->__cpu_power) | |
1da177e4 LT |
2598 | / SCHED_LOAD_SCALE; |
2599 | ||
2dd73a4f PW |
2600 | /* |
2601 | * if *imbalance is less than the average load per runnable task | |
2602 | * there is no gaurantee that any tasks will be moved so we'll have | |
2603 | * a think about bumping its value to force at least one task to be | |
2604 | * moved | |
2605 | */ | |
7fd0d2dd | 2606 | if (*imbalance < busiest_load_per_task) { |
48f24c4d | 2607 | unsigned long tmp, pwr_now, pwr_move; |
2dd73a4f PW |
2608 | unsigned int imbn; |
2609 | ||
2610 | small_imbalance: | |
2611 | pwr_move = pwr_now = 0; | |
2612 | imbn = 2; | |
2613 | if (this_nr_running) { | |
2614 | this_load_per_task /= this_nr_running; | |
2615 | if (busiest_load_per_task > this_load_per_task) | |
2616 | imbn = 1; | |
2617 | } else | |
2618 | this_load_per_task = SCHED_LOAD_SCALE; | |
1da177e4 | 2619 | |
dd41f596 IM |
2620 | if (max_load - this_load + SCHED_LOAD_SCALE_FUZZ >= |
2621 | busiest_load_per_task * imbn) { | |
2dd73a4f | 2622 | *imbalance = busiest_load_per_task; |
1da177e4 LT |
2623 | return busiest; |
2624 | } | |
2625 | ||
2626 | /* | |
2627 | * OK, we don't have enough imbalance to justify moving tasks, | |
2628 | * however we may be able to increase total CPU power used by | |
2629 | * moving them. | |
2630 | */ | |
2631 | ||
5517d86b ED |
2632 | pwr_now += busiest->__cpu_power * |
2633 | min(busiest_load_per_task, max_load); | |
2634 | pwr_now += this->__cpu_power * | |
2635 | min(this_load_per_task, this_load); | |
1da177e4 LT |
2636 | pwr_now /= SCHED_LOAD_SCALE; |
2637 | ||
2638 | /* Amount of load we'd subtract */ | |
5517d86b ED |
2639 | tmp = sg_div_cpu_power(busiest, |
2640 | busiest_load_per_task * SCHED_LOAD_SCALE); | |
1da177e4 | 2641 | if (max_load > tmp) |
5517d86b | 2642 | pwr_move += busiest->__cpu_power * |
2dd73a4f | 2643 | min(busiest_load_per_task, max_load - tmp); |
1da177e4 LT |
2644 | |
2645 | /* Amount of load we'd add */ | |
5517d86b | 2646 | if (max_load * busiest->__cpu_power < |
33859f7f | 2647 | busiest_load_per_task * SCHED_LOAD_SCALE) |
5517d86b ED |
2648 | tmp = sg_div_cpu_power(this, |
2649 | max_load * busiest->__cpu_power); | |
1da177e4 | 2650 | else |
5517d86b ED |
2651 | tmp = sg_div_cpu_power(this, |
2652 | busiest_load_per_task * SCHED_LOAD_SCALE); | |
2653 | pwr_move += this->__cpu_power * | |
2654 | min(this_load_per_task, this_load + tmp); | |
1da177e4 LT |
2655 | pwr_move /= SCHED_LOAD_SCALE; |
2656 | ||
2657 | /* Move if we gain throughput */ | |
7fd0d2dd SS |
2658 | if (pwr_move > pwr_now) |
2659 | *imbalance = busiest_load_per_task; | |
1da177e4 LT |
2660 | } |
2661 | ||
1da177e4 LT |
2662 | return busiest; |
2663 | ||
2664 | out_balanced: | |
5c45bf27 | 2665 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) |
d15bcfdb | 2666 | if (idle == CPU_NOT_IDLE || !(sd->flags & SD_POWERSAVINGS_BALANCE)) |
5c45bf27 | 2667 | goto ret; |
1da177e4 | 2668 | |
5c45bf27 SS |
2669 | if (this == group_leader && group_leader != group_min) { |
2670 | *imbalance = min_load_per_task; | |
2671 | return group_min; | |
2672 | } | |
5c45bf27 | 2673 | #endif |
783609c6 | 2674 | ret: |
1da177e4 LT |
2675 | *imbalance = 0; |
2676 | return NULL; | |
2677 | } | |
2678 | ||
2679 | /* | |
2680 | * find_busiest_queue - find the busiest runqueue among the cpus in group. | |
2681 | */ | |
70b97a7f | 2682 | static struct rq * |
d15bcfdb | 2683 | find_busiest_queue(struct sched_group *group, enum cpu_idle_type idle, |
0a2966b4 | 2684 | unsigned long imbalance, cpumask_t *cpus) |
1da177e4 | 2685 | { |
70b97a7f | 2686 | struct rq *busiest = NULL, *rq; |
2dd73a4f | 2687 | unsigned long max_load = 0; |
1da177e4 LT |
2688 | int i; |
2689 | ||
2690 | for_each_cpu_mask(i, group->cpumask) { | |
dd41f596 | 2691 | unsigned long wl; |
0a2966b4 CL |
2692 | |
2693 | if (!cpu_isset(i, *cpus)) | |
2694 | continue; | |
2695 | ||
48f24c4d | 2696 | rq = cpu_rq(i); |
dd41f596 | 2697 | wl = weighted_cpuload(i); |
2dd73a4f | 2698 | |
dd41f596 | 2699 | if (rq->nr_running == 1 && wl > imbalance) |
2dd73a4f | 2700 | continue; |
1da177e4 | 2701 | |
dd41f596 IM |
2702 | if (wl > max_load) { |
2703 | max_load = wl; | |
48f24c4d | 2704 | busiest = rq; |
1da177e4 LT |
2705 | } |
2706 | } | |
2707 | ||
2708 | return busiest; | |
2709 | } | |
2710 | ||
77391d71 NP |
2711 | /* |
2712 | * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but | |
2713 | * so long as it is large enough. | |
2714 | */ | |
2715 | #define MAX_PINNED_INTERVAL 512 | |
2716 | ||
1da177e4 LT |
2717 | /* |
2718 | * Check this_cpu to ensure it is balanced within domain. Attempt to move | |
2719 | * tasks if there is an imbalance. | |
1da177e4 | 2720 | */ |
70b97a7f | 2721 | static int load_balance(int this_cpu, struct rq *this_rq, |
d15bcfdb | 2722 | struct sched_domain *sd, enum cpu_idle_type idle, |
783609c6 | 2723 | int *balance) |
1da177e4 | 2724 | { |
43010659 | 2725 | int ld_moved, all_pinned = 0, active_balance = 0, sd_idle = 0; |
1da177e4 | 2726 | struct sched_group *group; |
1da177e4 | 2727 | unsigned long imbalance; |
70b97a7f | 2728 | struct rq *busiest; |
0a2966b4 | 2729 | cpumask_t cpus = CPU_MASK_ALL; |
fe2eea3f | 2730 | unsigned long flags; |
5969fe06 | 2731 | |
89c4710e SS |
2732 | /* |
2733 | * When power savings policy is enabled for the parent domain, idle | |
2734 | * sibling can pick up load irrespective of busy siblings. In this case, | |
dd41f596 | 2735 | * let the state of idle sibling percolate up as CPU_IDLE, instead of |
d15bcfdb | 2736 | * portraying it as CPU_NOT_IDLE. |
89c4710e | 2737 | */ |
d15bcfdb | 2738 | if (idle != CPU_NOT_IDLE && sd->flags & SD_SHARE_CPUPOWER && |
89c4710e | 2739 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
5969fe06 | 2740 | sd_idle = 1; |
1da177e4 | 2741 | |
2d72376b | 2742 | schedstat_inc(sd, lb_count[idle]); |
1da177e4 | 2743 | |
0a2966b4 CL |
2744 | redo: |
2745 | group = find_busiest_group(sd, this_cpu, &imbalance, idle, &sd_idle, | |
783609c6 SS |
2746 | &cpus, balance); |
2747 | ||
06066714 | 2748 | if (*balance == 0) |
783609c6 | 2749 | goto out_balanced; |
783609c6 | 2750 | |
1da177e4 LT |
2751 | if (!group) { |
2752 | schedstat_inc(sd, lb_nobusyg[idle]); | |
2753 | goto out_balanced; | |
2754 | } | |
2755 | ||
0a2966b4 | 2756 | busiest = find_busiest_queue(group, idle, imbalance, &cpus); |
1da177e4 LT |
2757 | if (!busiest) { |
2758 | schedstat_inc(sd, lb_nobusyq[idle]); | |
2759 | goto out_balanced; | |
2760 | } | |
2761 | ||
db935dbd | 2762 | BUG_ON(busiest == this_rq); |
1da177e4 LT |
2763 | |
2764 | schedstat_add(sd, lb_imbalance[idle], imbalance); | |
2765 | ||
43010659 | 2766 | ld_moved = 0; |
1da177e4 LT |
2767 | if (busiest->nr_running > 1) { |
2768 | /* | |
2769 | * Attempt to move tasks. If find_busiest_group has found | |
2770 | * an imbalance but busiest->nr_running <= 1, the group is | |
43010659 | 2771 | * still unbalanced. ld_moved simply stays zero, so it is |
1da177e4 LT |
2772 | * correctly treated as an imbalance. |
2773 | */ | |
fe2eea3f | 2774 | local_irq_save(flags); |
e17224bf | 2775 | double_rq_lock(this_rq, busiest); |
43010659 | 2776 | ld_moved = move_tasks(this_rq, this_cpu, busiest, |
48f24c4d | 2777 | imbalance, sd, idle, &all_pinned); |
e17224bf | 2778 | double_rq_unlock(this_rq, busiest); |
fe2eea3f | 2779 | local_irq_restore(flags); |
81026794 | 2780 | |
46cb4b7c SS |
2781 | /* |
2782 | * some other cpu did the load balance for us. | |
2783 | */ | |
43010659 | 2784 | if (ld_moved && this_cpu != smp_processor_id()) |
46cb4b7c SS |
2785 | resched_cpu(this_cpu); |
2786 | ||
81026794 | 2787 | /* All tasks on this runqueue were pinned by CPU affinity */ |
0a2966b4 CL |
2788 | if (unlikely(all_pinned)) { |
2789 | cpu_clear(cpu_of(busiest), cpus); | |
2790 | if (!cpus_empty(cpus)) | |
2791 | goto redo; | |
81026794 | 2792 | goto out_balanced; |
0a2966b4 | 2793 | } |
1da177e4 | 2794 | } |
81026794 | 2795 | |
43010659 | 2796 | if (!ld_moved) { |
1da177e4 LT |
2797 | schedstat_inc(sd, lb_failed[idle]); |
2798 | sd->nr_balance_failed++; | |
2799 | ||
2800 | if (unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2)) { | |
1da177e4 | 2801 | |
fe2eea3f | 2802 | spin_lock_irqsave(&busiest->lock, flags); |
fa3b6ddc SS |
2803 | |
2804 | /* don't kick the migration_thread, if the curr | |
2805 | * task on busiest cpu can't be moved to this_cpu | |
2806 | */ | |
2807 | if (!cpu_isset(this_cpu, busiest->curr->cpus_allowed)) { | |
fe2eea3f | 2808 | spin_unlock_irqrestore(&busiest->lock, flags); |
fa3b6ddc SS |
2809 | all_pinned = 1; |
2810 | goto out_one_pinned; | |
2811 | } | |
2812 | ||
1da177e4 LT |
2813 | if (!busiest->active_balance) { |
2814 | busiest->active_balance = 1; | |
2815 | busiest->push_cpu = this_cpu; | |
81026794 | 2816 | active_balance = 1; |
1da177e4 | 2817 | } |
fe2eea3f | 2818 | spin_unlock_irqrestore(&busiest->lock, flags); |
81026794 | 2819 | if (active_balance) |
1da177e4 LT |
2820 | wake_up_process(busiest->migration_thread); |
2821 | ||
2822 | /* | |
2823 | * We've kicked active balancing, reset the failure | |
2824 | * counter. | |
2825 | */ | |
39507451 | 2826 | sd->nr_balance_failed = sd->cache_nice_tries+1; |
1da177e4 | 2827 | } |
81026794 | 2828 | } else |
1da177e4 LT |
2829 | sd->nr_balance_failed = 0; |
2830 | ||
81026794 | 2831 | if (likely(!active_balance)) { |
1da177e4 LT |
2832 | /* We were unbalanced, so reset the balancing interval */ |
2833 | sd->balance_interval = sd->min_interval; | |
81026794 NP |
2834 | } else { |
2835 | /* | |
2836 | * If we've begun active balancing, start to back off. This | |
2837 | * case may not be covered by the all_pinned logic if there | |
2838 | * is only 1 task on the busy runqueue (because we don't call | |
2839 | * move_tasks). | |
2840 | */ | |
2841 | if (sd->balance_interval < sd->max_interval) | |
2842 | sd->balance_interval *= 2; | |
1da177e4 LT |
2843 | } |
2844 | ||
43010659 | 2845 | if (!ld_moved && !sd_idle && sd->flags & SD_SHARE_CPUPOWER && |
89c4710e | 2846 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
5969fe06 | 2847 | return -1; |
43010659 | 2848 | return ld_moved; |
1da177e4 LT |
2849 | |
2850 | out_balanced: | |
1da177e4 LT |
2851 | schedstat_inc(sd, lb_balanced[idle]); |
2852 | ||
16cfb1c0 | 2853 | sd->nr_balance_failed = 0; |
fa3b6ddc SS |
2854 | |
2855 | out_one_pinned: | |
1da177e4 | 2856 | /* tune up the balancing interval */ |
77391d71 NP |
2857 | if ((all_pinned && sd->balance_interval < MAX_PINNED_INTERVAL) || |
2858 | (sd->balance_interval < sd->max_interval)) | |
1da177e4 LT |
2859 | sd->balance_interval *= 2; |
2860 | ||
48f24c4d | 2861 | if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && |
89c4710e | 2862 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
5969fe06 | 2863 | return -1; |
1da177e4 LT |
2864 | return 0; |
2865 | } | |
2866 | ||
2867 | /* | |
2868 | * Check this_cpu to ensure it is balanced within domain. Attempt to move | |
2869 | * tasks if there is an imbalance. | |
2870 | * | |
d15bcfdb | 2871 | * Called from schedule when this_rq is about to become idle (CPU_NEWLY_IDLE). |
1da177e4 LT |
2872 | * this_rq is locked. |
2873 | */ | |
48f24c4d | 2874 | static int |
70b97a7f | 2875 | load_balance_newidle(int this_cpu, struct rq *this_rq, struct sched_domain *sd) |
1da177e4 LT |
2876 | { |
2877 | struct sched_group *group; | |
70b97a7f | 2878 | struct rq *busiest = NULL; |
1da177e4 | 2879 | unsigned long imbalance; |
43010659 | 2880 | int ld_moved = 0; |
5969fe06 | 2881 | int sd_idle = 0; |
969bb4e4 | 2882 | int all_pinned = 0; |
0a2966b4 | 2883 | cpumask_t cpus = CPU_MASK_ALL; |
5969fe06 | 2884 | |
89c4710e SS |
2885 | /* |
2886 | * When power savings policy is enabled for the parent domain, idle | |
2887 | * sibling can pick up load irrespective of busy siblings. In this case, | |
2888 | * let the state of idle sibling percolate up as IDLE, instead of | |
d15bcfdb | 2889 | * portraying it as CPU_NOT_IDLE. |
89c4710e SS |
2890 | */ |
2891 | if (sd->flags & SD_SHARE_CPUPOWER && | |
2892 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) | |
5969fe06 | 2893 | sd_idle = 1; |
1da177e4 | 2894 | |
2d72376b | 2895 | schedstat_inc(sd, lb_count[CPU_NEWLY_IDLE]); |
0a2966b4 | 2896 | redo: |
d15bcfdb | 2897 | group = find_busiest_group(sd, this_cpu, &imbalance, CPU_NEWLY_IDLE, |
783609c6 | 2898 | &sd_idle, &cpus, NULL); |
1da177e4 | 2899 | if (!group) { |
d15bcfdb | 2900 | schedstat_inc(sd, lb_nobusyg[CPU_NEWLY_IDLE]); |
16cfb1c0 | 2901 | goto out_balanced; |
1da177e4 LT |
2902 | } |
2903 | ||
d15bcfdb | 2904 | busiest = find_busiest_queue(group, CPU_NEWLY_IDLE, imbalance, |
0a2966b4 | 2905 | &cpus); |
db935dbd | 2906 | if (!busiest) { |
d15bcfdb | 2907 | schedstat_inc(sd, lb_nobusyq[CPU_NEWLY_IDLE]); |
16cfb1c0 | 2908 | goto out_balanced; |
1da177e4 LT |
2909 | } |
2910 | ||
db935dbd NP |
2911 | BUG_ON(busiest == this_rq); |
2912 | ||
d15bcfdb | 2913 | schedstat_add(sd, lb_imbalance[CPU_NEWLY_IDLE], imbalance); |
d6d5cfaf | 2914 | |
43010659 | 2915 | ld_moved = 0; |
d6d5cfaf NP |
2916 | if (busiest->nr_running > 1) { |
2917 | /* Attempt to move tasks */ | |
2918 | double_lock_balance(this_rq, busiest); | |
6e82a3be IM |
2919 | /* this_rq->clock is already updated */ |
2920 | update_rq_clock(busiest); | |
43010659 | 2921 | ld_moved = move_tasks(this_rq, this_cpu, busiest, |
969bb4e4 SS |
2922 | imbalance, sd, CPU_NEWLY_IDLE, |
2923 | &all_pinned); | |
d6d5cfaf | 2924 | spin_unlock(&busiest->lock); |
0a2966b4 | 2925 | |
969bb4e4 | 2926 | if (unlikely(all_pinned)) { |
0a2966b4 CL |
2927 | cpu_clear(cpu_of(busiest), cpus); |
2928 | if (!cpus_empty(cpus)) | |
2929 | goto redo; | |
2930 | } | |
d6d5cfaf NP |
2931 | } |
2932 | ||
43010659 | 2933 | if (!ld_moved) { |
d15bcfdb | 2934 | schedstat_inc(sd, lb_failed[CPU_NEWLY_IDLE]); |
89c4710e SS |
2935 | if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && |
2936 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) | |
5969fe06 NP |
2937 | return -1; |
2938 | } else | |
16cfb1c0 | 2939 | sd->nr_balance_failed = 0; |
1da177e4 | 2940 | |
43010659 | 2941 | return ld_moved; |
16cfb1c0 NP |
2942 | |
2943 | out_balanced: | |
d15bcfdb | 2944 | schedstat_inc(sd, lb_balanced[CPU_NEWLY_IDLE]); |
48f24c4d | 2945 | if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && |
89c4710e | 2946 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
5969fe06 | 2947 | return -1; |
16cfb1c0 | 2948 | sd->nr_balance_failed = 0; |
48f24c4d | 2949 | |
16cfb1c0 | 2950 | return 0; |
1da177e4 LT |
2951 | } |
2952 | ||
2953 | /* | |
2954 | * idle_balance is called by schedule() if this_cpu is about to become | |
2955 | * idle. Attempts to pull tasks from other CPUs. | |
2956 | */ | |
70b97a7f | 2957 | static void idle_balance(int this_cpu, struct rq *this_rq) |
1da177e4 LT |
2958 | { |
2959 | struct sched_domain *sd; | |
dd41f596 IM |
2960 | int pulled_task = -1; |
2961 | unsigned long next_balance = jiffies + HZ; | |
1da177e4 LT |
2962 | |
2963 | for_each_domain(this_cpu, sd) { | |
92c4ca5c CL |
2964 | unsigned long interval; |
2965 | ||
2966 | if (!(sd->flags & SD_LOAD_BALANCE)) | |
2967 | continue; | |
2968 | ||
2969 | if (sd->flags & SD_BALANCE_NEWIDLE) | |
48f24c4d | 2970 | /* If we've pulled tasks over stop searching: */ |
1bd77f2d | 2971 | pulled_task = load_balance_newidle(this_cpu, |
92c4ca5c CL |
2972 | this_rq, sd); |
2973 | ||
2974 | interval = msecs_to_jiffies(sd->balance_interval); | |
2975 | if (time_after(next_balance, sd->last_balance + interval)) | |
2976 | next_balance = sd->last_balance + interval; | |
2977 | if (pulled_task) | |
2978 | break; | |
1da177e4 | 2979 | } |
dd41f596 | 2980 | if (pulled_task || time_after(jiffies, this_rq->next_balance)) { |
1bd77f2d CL |
2981 | /* |
2982 | * We are going idle. next_balance may be set based on | |
2983 | * a busy processor. So reset next_balance. | |
2984 | */ | |
2985 | this_rq->next_balance = next_balance; | |
dd41f596 | 2986 | } |
1da177e4 LT |
2987 | } |
2988 | ||
2989 | /* | |
2990 | * active_load_balance is run by migration threads. It pushes running tasks | |
2991 | * off the busiest CPU onto idle CPUs. It requires at least 1 task to be | |
2992 | * running on each physical CPU where possible, and avoids physical / | |
2993 | * logical imbalances. | |
2994 | * | |
2995 | * Called with busiest_rq locked. | |
2996 | */ | |
70b97a7f | 2997 | static void active_load_balance(struct rq *busiest_rq, int busiest_cpu) |
1da177e4 | 2998 | { |
39507451 | 2999 | int target_cpu = busiest_rq->push_cpu; |
70b97a7f IM |
3000 | struct sched_domain *sd; |
3001 | struct rq *target_rq; | |
39507451 | 3002 | |
48f24c4d | 3003 | /* Is there any task to move? */ |
39507451 | 3004 | if (busiest_rq->nr_running <= 1) |
39507451 NP |
3005 | return; |
3006 | ||
3007 | target_rq = cpu_rq(target_cpu); | |
1da177e4 LT |
3008 | |
3009 | /* | |
39507451 | 3010 | * This condition is "impossible", if it occurs |
41a2d6cf | 3011 | * we need to fix it. Originally reported by |
39507451 | 3012 | * Bjorn Helgaas on a 128-cpu setup. |
1da177e4 | 3013 | */ |
39507451 | 3014 | BUG_ON(busiest_rq == target_rq); |
1da177e4 | 3015 | |
39507451 NP |
3016 | /* move a task from busiest_rq to target_rq */ |
3017 | double_lock_balance(busiest_rq, target_rq); | |
6e82a3be IM |
3018 | update_rq_clock(busiest_rq); |
3019 | update_rq_clock(target_rq); | |
39507451 NP |
3020 | |
3021 | /* Search for an sd spanning us and the target CPU. */ | |
c96d145e | 3022 | for_each_domain(target_cpu, sd) { |
39507451 | 3023 | if ((sd->flags & SD_LOAD_BALANCE) && |
48f24c4d | 3024 | cpu_isset(busiest_cpu, sd->span)) |
39507451 | 3025 | break; |
c96d145e | 3026 | } |
39507451 | 3027 | |
48f24c4d | 3028 | if (likely(sd)) { |
2d72376b | 3029 | schedstat_inc(sd, alb_count); |
39507451 | 3030 | |
43010659 PW |
3031 | if (move_one_task(target_rq, target_cpu, busiest_rq, |
3032 | sd, CPU_IDLE)) | |
48f24c4d IM |
3033 | schedstat_inc(sd, alb_pushed); |
3034 | else | |
3035 | schedstat_inc(sd, alb_failed); | |
3036 | } | |
39507451 | 3037 | spin_unlock(&target_rq->lock); |
1da177e4 LT |
3038 | } |
3039 | ||
46cb4b7c SS |
3040 | #ifdef CONFIG_NO_HZ |
3041 | static struct { | |
3042 | atomic_t load_balancer; | |
41a2d6cf | 3043 | cpumask_t cpu_mask; |
46cb4b7c SS |
3044 | } nohz ____cacheline_aligned = { |
3045 | .load_balancer = ATOMIC_INIT(-1), | |
3046 | .cpu_mask = CPU_MASK_NONE, | |
3047 | }; | |
3048 | ||
7835b98b | 3049 | /* |
46cb4b7c SS |
3050 | * This routine will try to nominate the ilb (idle load balancing) |
3051 | * owner among the cpus whose ticks are stopped. ilb owner will do the idle | |
3052 | * load balancing on behalf of all those cpus. If all the cpus in the system | |
3053 | * go into this tickless mode, then there will be no ilb owner (as there is | |
3054 | * no need for one) and all the cpus will sleep till the next wakeup event | |
3055 | * arrives... | |
3056 | * | |
3057 | * For the ilb owner, tick is not stopped. And this tick will be used | |
3058 | * for idle load balancing. ilb owner will still be part of | |
3059 | * nohz.cpu_mask.. | |
7835b98b | 3060 | * |
46cb4b7c SS |
3061 | * While stopping the tick, this cpu will become the ilb owner if there |
3062 | * is no other owner. And will be the owner till that cpu becomes busy | |
3063 | * or if all cpus in the system stop their ticks at which point | |
3064 | * there is no need for ilb owner. | |
3065 | * | |
3066 | * When the ilb owner becomes busy, it nominates another owner, during the | |
3067 | * next busy scheduler_tick() | |
3068 | */ | |
3069 | int select_nohz_load_balancer(int stop_tick) | |
3070 | { | |
3071 | int cpu = smp_processor_id(); | |
3072 | ||
3073 | if (stop_tick) { | |
3074 | cpu_set(cpu, nohz.cpu_mask); | |
3075 | cpu_rq(cpu)->in_nohz_recently = 1; | |
3076 | ||
3077 | /* | |
3078 | * If we are going offline and still the leader, give up! | |
3079 | */ | |
3080 | if (cpu_is_offline(cpu) && | |
3081 | atomic_read(&nohz.load_balancer) == cpu) { | |
3082 | if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu) | |
3083 | BUG(); | |
3084 | return 0; | |
3085 | } | |
3086 | ||
3087 | /* time for ilb owner also to sleep */ | |
3088 | if (cpus_weight(nohz.cpu_mask) == num_online_cpus()) { | |
3089 | if (atomic_read(&nohz.load_balancer) == cpu) | |
3090 | atomic_set(&nohz.load_balancer, -1); | |
3091 | return 0; | |
3092 | } | |
3093 | ||
3094 | if (atomic_read(&nohz.load_balancer) == -1) { | |
3095 | /* make me the ilb owner */ | |
3096 | if (atomic_cmpxchg(&nohz.load_balancer, -1, cpu) == -1) | |
3097 | return 1; | |
3098 | } else if (atomic_read(&nohz.load_balancer) == cpu) | |
3099 | return 1; | |
3100 | } else { | |
3101 | if (!cpu_isset(cpu, nohz.cpu_mask)) | |
3102 | return 0; | |
3103 | ||
3104 | cpu_clear(cpu, nohz.cpu_mask); | |
3105 | ||
3106 | if (atomic_read(&nohz.load_balancer) == cpu) | |
3107 | if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu) | |
3108 | BUG(); | |
3109 | } | |
3110 | return 0; | |
3111 | } | |
3112 | #endif | |
3113 | ||
3114 | static DEFINE_SPINLOCK(balancing); | |
3115 | ||
3116 | /* | |
7835b98b CL |
3117 | * It checks each scheduling domain to see if it is due to be balanced, |
3118 | * and initiates a balancing operation if so. | |
3119 | * | |
3120 | * Balancing parameters are set up in arch_init_sched_domains. | |
3121 | */ | |
a9957449 | 3122 | static void rebalance_domains(int cpu, enum cpu_idle_type idle) |
7835b98b | 3123 | { |
46cb4b7c SS |
3124 | int balance = 1; |
3125 | struct rq *rq = cpu_rq(cpu); | |
7835b98b CL |
3126 | unsigned long interval; |
3127 | struct sched_domain *sd; | |
46cb4b7c | 3128 | /* Earliest time when we have to do rebalance again */ |
c9819f45 | 3129 | unsigned long next_balance = jiffies + 60*HZ; |
f549da84 | 3130 | int update_next_balance = 0; |
1da177e4 | 3131 | |
46cb4b7c | 3132 | for_each_domain(cpu, sd) { |
1da177e4 LT |
3133 | if (!(sd->flags & SD_LOAD_BALANCE)) |
3134 | continue; | |
3135 | ||
3136 | interval = sd->balance_interval; | |
d15bcfdb | 3137 | if (idle != CPU_IDLE) |
1da177e4 LT |
3138 | interval *= sd->busy_factor; |
3139 | ||
3140 | /* scale ms to jiffies */ | |
3141 | interval = msecs_to_jiffies(interval); | |
3142 | if (unlikely(!interval)) | |
3143 | interval = 1; | |
dd41f596 IM |
3144 | if (interval > HZ*NR_CPUS/10) |
3145 | interval = HZ*NR_CPUS/10; | |
3146 | ||
1da177e4 | 3147 | |
08c183f3 CL |
3148 | if (sd->flags & SD_SERIALIZE) { |
3149 | if (!spin_trylock(&balancing)) | |
3150 | goto out; | |
3151 | } | |
3152 | ||
c9819f45 | 3153 | if (time_after_eq(jiffies, sd->last_balance + interval)) { |
46cb4b7c | 3154 | if (load_balance(cpu, rq, sd, idle, &balance)) { |
fa3b6ddc SS |
3155 | /* |
3156 | * We've pulled tasks over so either we're no | |
5969fe06 NP |
3157 | * longer idle, or one of our SMT siblings is |
3158 | * not idle. | |
3159 | */ | |
d15bcfdb | 3160 | idle = CPU_NOT_IDLE; |
1da177e4 | 3161 | } |
1bd77f2d | 3162 | sd->last_balance = jiffies; |
1da177e4 | 3163 | } |
08c183f3 CL |
3164 | if (sd->flags & SD_SERIALIZE) |
3165 | spin_unlock(&balancing); | |
3166 | out: | |
f549da84 | 3167 | if (time_after(next_balance, sd->last_balance + interval)) { |
c9819f45 | 3168 | next_balance = sd->last_balance + interval; |
f549da84 SS |
3169 | update_next_balance = 1; |
3170 | } | |
783609c6 SS |
3171 | |
3172 | /* | |
3173 | * Stop the load balance at this level. There is another | |
3174 | * CPU in our sched group which is doing load balancing more | |
3175 | * actively. | |
3176 | */ | |
3177 | if (!balance) | |
3178 | break; | |
1da177e4 | 3179 | } |
f549da84 SS |
3180 | |
3181 | /* | |
3182 | * next_balance will be updated only when there is a need. | |
3183 | * When the cpu is attached to null domain for ex, it will not be | |
3184 | * updated. | |
3185 | */ | |
3186 | if (likely(update_next_balance)) | |
3187 | rq->next_balance = next_balance; | |
46cb4b7c SS |
3188 | } |
3189 | ||
3190 | /* | |
3191 | * run_rebalance_domains is triggered when needed from the scheduler tick. | |
3192 | * In CONFIG_NO_HZ case, the idle load balance owner will do the | |
3193 | * rebalancing for all the cpus for whom scheduler ticks are stopped. | |
3194 | */ | |
3195 | static void run_rebalance_domains(struct softirq_action *h) | |
3196 | { | |
dd41f596 IM |
3197 | int this_cpu = smp_processor_id(); |
3198 | struct rq *this_rq = cpu_rq(this_cpu); | |
3199 | enum cpu_idle_type idle = this_rq->idle_at_tick ? | |
3200 | CPU_IDLE : CPU_NOT_IDLE; | |
46cb4b7c | 3201 | |
dd41f596 | 3202 | rebalance_domains(this_cpu, idle); |
46cb4b7c SS |
3203 | |
3204 | #ifdef CONFIG_NO_HZ | |
3205 | /* | |
3206 | * If this cpu is the owner for idle load balancing, then do the | |
3207 | * balancing on behalf of the other idle cpus whose ticks are | |
3208 | * stopped. | |
3209 | */ | |
dd41f596 IM |
3210 | if (this_rq->idle_at_tick && |
3211 | atomic_read(&nohz.load_balancer) == this_cpu) { | |
46cb4b7c SS |
3212 | cpumask_t cpus = nohz.cpu_mask; |
3213 | struct rq *rq; | |
3214 | int balance_cpu; | |
3215 | ||
dd41f596 | 3216 | cpu_clear(this_cpu, cpus); |
46cb4b7c SS |
3217 | for_each_cpu_mask(balance_cpu, cpus) { |
3218 | /* | |
3219 | * If this cpu gets work to do, stop the load balancing | |
3220 | * work being done for other cpus. Next load | |
3221 | * balancing owner will pick it up. | |
3222 | */ | |
3223 | if (need_resched()) | |
3224 | break; | |
3225 | ||
de0cf899 | 3226 | rebalance_domains(balance_cpu, CPU_IDLE); |
46cb4b7c SS |
3227 | |
3228 | rq = cpu_rq(balance_cpu); | |
dd41f596 IM |
3229 | if (time_after(this_rq->next_balance, rq->next_balance)) |
3230 | this_rq->next_balance = rq->next_balance; | |
46cb4b7c SS |
3231 | } |
3232 | } | |
3233 | #endif | |
3234 | } | |
3235 | ||
3236 | /* | |
3237 | * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing. | |
3238 | * | |
3239 | * In case of CONFIG_NO_HZ, this is the place where we nominate a new | |
3240 | * idle load balancing owner or decide to stop the periodic load balancing, | |
3241 | * if the whole system is idle. | |
3242 | */ | |
dd41f596 | 3243 | static inline void trigger_load_balance(struct rq *rq, int cpu) |
46cb4b7c | 3244 | { |
46cb4b7c SS |
3245 | #ifdef CONFIG_NO_HZ |
3246 | /* | |
3247 | * If we were in the nohz mode recently and busy at the current | |
3248 | * scheduler tick, then check if we need to nominate new idle | |
3249 | * load balancer. | |
3250 | */ | |
3251 | if (rq->in_nohz_recently && !rq->idle_at_tick) { | |
3252 | rq->in_nohz_recently = 0; | |
3253 | ||
3254 | if (atomic_read(&nohz.load_balancer) == cpu) { | |
3255 | cpu_clear(cpu, nohz.cpu_mask); | |
3256 | atomic_set(&nohz.load_balancer, -1); | |
3257 | } | |
3258 | ||
3259 | if (atomic_read(&nohz.load_balancer) == -1) { | |
3260 | /* | |
3261 | * simple selection for now: Nominate the | |
3262 | * first cpu in the nohz list to be the next | |
3263 | * ilb owner. | |
3264 | * | |
3265 | * TBD: Traverse the sched domains and nominate | |
3266 | * the nearest cpu in the nohz.cpu_mask. | |
3267 | */ | |
3268 | int ilb = first_cpu(nohz.cpu_mask); | |
3269 | ||
3270 | if (ilb != NR_CPUS) | |
3271 | resched_cpu(ilb); | |
3272 | } | |
3273 | } | |
3274 | ||
3275 | /* | |
3276 | * If this cpu is idle and doing idle load balancing for all the | |
3277 | * cpus with ticks stopped, is it time for that to stop? | |
3278 | */ | |
3279 | if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) == cpu && | |
3280 | cpus_weight(nohz.cpu_mask) == num_online_cpus()) { | |
3281 | resched_cpu(cpu); | |
3282 | return; | |
3283 | } | |
3284 | ||
3285 | /* | |
3286 | * If this cpu is idle and the idle load balancing is done by | |
3287 | * someone else, then no need raise the SCHED_SOFTIRQ | |
3288 | */ | |
3289 | if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) != cpu && | |
3290 | cpu_isset(cpu, nohz.cpu_mask)) | |
3291 | return; | |
3292 | #endif | |
3293 | if (time_after_eq(jiffies, rq->next_balance)) | |
3294 | raise_softirq(SCHED_SOFTIRQ); | |
1da177e4 | 3295 | } |
dd41f596 IM |
3296 | |
3297 | #else /* CONFIG_SMP */ | |
3298 | ||
1da177e4 LT |
3299 | /* |
3300 | * on UP we do not need to balance between CPUs: | |
3301 | */ | |
70b97a7f | 3302 | static inline void idle_balance(int cpu, struct rq *rq) |
1da177e4 LT |
3303 | { |
3304 | } | |
dd41f596 | 3305 | |
1da177e4 LT |
3306 | #endif |
3307 | ||
1da177e4 LT |
3308 | DEFINE_PER_CPU(struct kernel_stat, kstat); |
3309 | ||
3310 | EXPORT_PER_CPU_SYMBOL(kstat); | |
3311 | ||
3312 | /* | |
41b86e9c IM |
3313 | * Return p->sum_exec_runtime plus any more ns on the sched_clock |
3314 | * that have not yet been banked in case the task is currently running. | |
1da177e4 | 3315 | */ |
41b86e9c | 3316 | unsigned long long task_sched_runtime(struct task_struct *p) |
1da177e4 | 3317 | { |
1da177e4 | 3318 | unsigned long flags; |
41b86e9c IM |
3319 | u64 ns, delta_exec; |
3320 | struct rq *rq; | |
48f24c4d | 3321 | |
41b86e9c IM |
3322 | rq = task_rq_lock(p, &flags); |
3323 | ns = p->se.sum_exec_runtime; | |
051a1d1a | 3324 | if (task_current(rq, p)) { |
a8e504d2 IM |
3325 | update_rq_clock(rq); |
3326 | delta_exec = rq->clock - p->se.exec_start; | |
41b86e9c IM |
3327 | if ((s64)delta_exec > 0) |
3328 | ns += delta_exec; | |
3329 | } | |
3330 | task_rq_unlock(rq, &flags); | |
48f24c4d | 3331 | |
1da177e4 LT |
3332 | return ns; |
3333 | } | |
3334 | ||
1da177e4 LT |
3335 | /* |
3336 | * Account user cpu time to a process. | |
3337 | * @p: the process that the cpu time gets accounted to | |
1da177e4 LT |
3338 | * @cputime: the cpu time spent in user space since the last update |
3339 | */ | |
3340 | void account_user_time(struct task_struct *p, cputime_t cputime) | |
3341 | { | |
3342 | struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; | |
3343 | cputime64_t tmp; | |
3344 | ||
3345 | p->utime = cputime_add(p->utime, cputime); | |
3346 | ||
3347 | /* Add user time to cpustat. */ | |
3348 | tmp = cputime_to_cputime64(cputime); | |
3349 | if (TASK_NICE(p) > 0) | |
3350 | cpustat->nice = cputime64_add(cpustat->nice, tmp); | |
3351 | else | |
3352 | cpustat->user = cputime64_add(cpustat->user, tmp); | |
3353 | } | |
3354 | ||
94886b84 LV |
3355 | /* |
3356 | * Account guest cpu time to a process. | |
3357 | * @p: the process that the cpu time gets accounted to | |
3358 | * @cputime: the cpu time spent in virtual machine since the last update | |
3359 | */ | |
f7402e03 | 3360 | static void account_guest_time(struct task_struct *p, cputime_t cputime) |
94886b84 LV |
3361 | { |
3362 | cputime64_t tmp; | |
3363 | struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; | |
3364 | ||
3365 | tmp = cputime_to_cputime64(cputime); | |
3366 | ||
3367 | p->utime = cputime_add(p->utime, cputime); | |
3368 | p->gtime = cputime_add(p->gtime, cputime); | |
3369 | ||
3370 | cpustat->user = cputime64_add(cpustat->user, tmp); | |
3371 | cpustat->guest = cputime64_add(cpustat->guest, tmp); | |
3372 | } | |
3373 | ||
c66f08be MN |
3374 | /* |
3375 | * Account scaled user cpu time to a process. | |
3376 | * @p: the process that the cpu time gets accounted to | |
3377 | * @cputime: the cpu time spent in user space since the last update | |
3378 | */ | |
3379 | void account_user_time_scaled(struct task_struct *p, cputime_t cputime) | |
3380 | { | |
3381 | p->utimescaled = cputime_add(p->utimescaled, cputime); | |
3382 | } | |
3383 | ||
1da177e4 LT |
3384 | /* |
3385 | * Account system cpu time to a process. | |
3386 | * @p: the process that the cpu time gets accounted to | |
3387 | * @hardirq_offset: the offset to subtract from hardirq_count() | |
3388 | * @cputime: the cpu time spent in kernel space since the last update | |
3389 | */ | |
3390 | void account_system_time(struct task_struct *p, int hardirq_offset, | |
3391 | cputime_t cputime) | |
3392 | { | |
3393 | struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; | |
70b97a7f | 3394 | struct rq *rq = this_rq(); |
1da177e4 LT |
3395 | cputime64_t tmp; |
3396 | ||
9778385d CB |
3397 | if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) |
3398 | return account_guest_time(p, cputime); | |
94886b84 | 3399 | |
1da177e4 LT |
3400 | p->stime = cputime_add(p->stime, cputime); |
3401 | ||
3402 | /* Add system time to cpustat. */ | |
3403 | tmp = cputime_to_cputime64(cputime); | |
3404 | if (hardirq_count() - hardirq_offset) | |
3405 | cpustat->irq = cputime64_add(cpustat->irq, tmp); | |
3406 | else if (softirq_count()) | |
3407 | cpustat->softirq = cputime64_add(cpustat->softirq, tmp); | |
cfb52856 | 3408 | else if (p != rq->idle) |
1da177e4 | 3409 | cpustat->system = cputime64_add(cpustat->system, tmp); |
cfb52856 | 3410 | else if (atomic_read(&rq->nr_iowait) > 0) |
1da177e4 LT |
3411 | cpustat->iowait = cputime64_add(cpustat->iowait, tmp); |
3412 | else | |
3413 | cpustat->idle = cputime64_add(cpustat->idle, tmp); | |
3414 | /* Account for system time used */ | |
3415 | acct_update_integrals(p); | |
1da177e4 LT |
3416 | } |
3417 | ||
c66f08be MN |
3418 | /* |
3419 | * Account scaled system cpu time to a process. | |
3420 | * @p: the process that the cpu time gets accounted to | |
3421 | * @hardirq_offset: the offset to subtract from hardirq_count() | |
3422 | * @cputime: the cpu time spent in kernel space since the last update | |
3423 | */ | |
3424 | void account_system_time_scaled(struct task_struct *p, cputime_t cputime) | |
3425 | { | |
3426 | p->stimescaled = cputime_add(p->stimescaled, cputime); | |
3427 | } | |
3428 | ||
1da177e4 LT |
3429 | /* |
3430 | * Account for involuntary wait time. | |
3431 | * @p: the process from which the cpu time has been stolen | |
3432 | * @steal: the cpu time spent in involuntary wait | |
3433 | */ | |
3434 | void account_steal_time(struct task_struct *p, cputime_t steal) | |
3435 | { | |
3436 | struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; | |
3437 | cputime64_t tmp = cputime_to_cputime64(steal); | |
70b97a7f | 3438 | struct rq *rq = this_rq(); |
1da177e4 LT |
3439 | |
3440 | if (p == rq->idle) { | |
3441 | p->stime = cputime_add(p->stime, steal); | |
3442 | if (atomic_read(&rq->nr_iowait) > 0) | |
3443 | cpustat->iowait = cputime64_add(cpustat->iowait, tmp); | |
3444 | else | |
3445 | cpustat->idle = cputime64_add(cpustat->idle, tmp); | |
cfb52856 | 3446 | } else |
1da177e4 LT |
3447 | cpustat->steal = cputime64_add(cpustat->steal, tmp); |
3448 | } | |
3449 | ||
7835b98b CL |
3450 | /* |
3451 | * This function gets called by the timer code, with HZ frequency. | |
3452 | * We call it with interrupts disabled. | |
3453 | * | |
3454 | * It also gets called by the fork code, when changing the parent's | |
3455 | * timeslices. | |
3456 | */ | |
3457 | void scheduler_tick(void) | |
3458 | { | |
7835b98b CL |
3459 | int cpu = smp_processor_id(); |
3460 | struct rq *rq = cpu_rq(cpu); | |
dd41f596 | 3461 | struct task_struct *curr = rq->curr; |
529c7726 | 3462 | u64 next_tick = rq->tick_timestamp + TICK_NSEC; |
dd41f596 IM |
3463 | |
3464 | spin_lock(&rq->lock); | |
546fe3c9 | 3465 | __update_rq_clock(rq); |
529c7726 IM |
3466 | /* |
3467 | * Let rq->clock advance by at least TICK_NSEC: | |
3468 | */ | |
3469 | if (unlikely(rq->clock < next_tick)) | |
3470 | rq->clock = next_tick; | |
3471 | rq->tick_timestamp = rq->clock; | |
f1a438d8 | 3472 | update_cpu_load(rq); |
dd41f596 IM |
3473 | if (curr != rq->idle) /* FIXME: needed? */ |
3474 | curr->sched_class->task_tick(rq, curr); | |
dd41f596 | 3475 | spin_unlock(&rq->lock); |
7835b98b | 3476 | |
e418e1c2 | 3477 | #ifdef CONFIG_SMP |
dd41f596 IM |
3478 | rq->idle_at_tick = idle_cpu(cpu); |
3479 | trigger_load_balance(rq, cpu); | |
e418e1c2 | 3480 | #endif |
1da177e4 LT |
3481 | } |
3482 | ||
1da177e4 LT |
3483 | #if defined(CONFIG_PREEMPT) && defined(CONFIG_DEBUG_PREEMPT) |
3484 | ||
3485 | void fastcall add_preempt_count(int val) | |
3486 | { | |
3487 | /* | |
3488 | * Underflow? | |
3489 | */ | |
9a11b49a IM |
3490 | if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0))) |
3491 | return; | |
1da177e4 LT |
3492 | preempt_count() += val; |
3493 | /* | |
3494 | * Spinlock count overflowing soon? | |
3495 | */ | |
33859f7f MOS |
3496 | DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >= |
3497 | PREEMPT_MASK - 10); | |
1da177e4 LT |
3498 | } |
3499 | EXPORT_SYMBOL(add_preempt_count); | |
3500 | ||
3501 | void fastcall sub_preempt_count(int val) | |
3502 | { | |
3503 | /* | |
3504 | * Underflow? | |
3505 | */ | |
9a11b49a IM |
3506 | if (DEBUG_LOCKS_WARN_ON(val > preempt_count())) |
3507 | return; | |
1da177e4 LT |
3508 | /* |
3509 | * Is the spinlock portion underflowing? | |
3510 | */ | |
9a11b49a IM |
3511 | if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) && |
3512 | !(preempt_count() & PREEMPT_MASK))) | |
3513 | return; | |
3514 | ||
1da177e4 LT |
3515 | preempt_count() -= val; |
3516 | } | |
3517 | EXPORT_SYMBOL(sub_preempt_count); | |
3518 | ||
3519 | #endif | |
3520 | ||
3521 | /* | |
dd41f596 | 3522 | * Print scheduling while atomic bug: |
1da177e4 | 3523 | */ |
dd41f596 | 3524 | static noinline void __schedule_bug(struct task_struct *prev) |
1da177e4 | 3525 | { |
838225b4 SS |
3526 | struct pt_regs *regs = get_irq_regs(); |
3527 | ||
3528 | printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n", | |
3529 | prev->comm, prev->pid, preempt_count()); | |
3530 | ||
dd41f596 IM |
3531 | debug_show_held_locks(prev); |
3532 | if (irqs_disabled()) | |
3533 | print_irqtrace_events(prev); | |
838225b4 SS |
3534 | |
3535 | if (regs) | |
3536 | show_regs(regs); | |
3537 | else | |
3538 | dump_stack(); | |
dd41f596 | 3539 | } |
1da177e4 | 3540 | |
dd41f596 IM |
3541 | /* |
3542 | * Various schedule()-time debugging checks and statistics: | |
3543 | */ | |
3544 | static inline void schedule_debug(struct task_struct *prev) | |
3545 | { | |
1da177e4 | 3546 | /* |
41a2d6cf | 3547 | * Test if we are atomic. Since do_exit() needs to call into |
1da177e4 LT |
3548 | * schedule() atomically, we ignore that path for now. |
3549 | * Otherwise, whine if we are scheduling when we should not be. | |
3550 | */ | |
dd41f596 IM |
3551 | if (unlikely(in_atomic_preempt_off()) && unlikely(!prev->exit_state)) |
3552 | __schedule_bug(prev); | |
3553 | ||
1da177e4 LT |
3554 | profile_hit(SCHED_PROFILING, __builtin_return_address(0)); |
3555 | ||
2d72376b | 3556 | schedstat_inc(this_rq(), sched_count); |
b8efb561 IM |
3557 | #ifdef CONFIG_SCHEDSTATS |
3558 | if (unlikely(prev->lock_depth >= 0)) { | |
2d72376b IM |
3559 | schedstat_inc(this_rq(), bkl_count); |
3560 | schedstat_inc(prev, sched_info.bkl_count); | |
b8efb561 IM |
3561 | } |
3562 | #endif | |
dd41f596 IM |
3563 | } |
3564 | ||
3565 | /* | |
3566 | * Pick up the highest-prio task: | |
3567 | */ | |
3568 | static inline struct task_struct * | |
ff95f3df | 3569 | pick_next_task(struct rq *rq, struct task_struct *prev) |
dd41f596 | 3570 | { |
5522d5d5 | 3571 | const struct sched_class *class; |
dd41f596 | 3572 | struct task_struct *p; |
1da177e4 LT |
3573 | |
3574 | /* | |
dd41f596 IM |
3575 | * Optimization: we know that if all tasks are in |
3576 | * the fair class we can call that function directly: | |
1da177e4 | 3577 | */ |
dd41f596 | 3578 | if (likely(rq->nr_running == rq->cfs.nr_running)) { |
fb8d4724 | 3579 | p = fair_sched_class.pick_next_task(rq); |
dd41f596 IM |
3580 | if (likely(p)) |
3581 | return p; | |
1da177e4 LT |
3582 | } |
3583 | ||
dd41f596 IM |
3584 | class = sched_class_highest; |
3585 | for ( ; ; ) { | |
fb8d4724 | 3586 | p = class->pick_next_task(rq); |
dd41f596 IM |
3587 | if (p) |
3588 | return p; | |
3589 | /* | |
3590 | * Will never be NULL as the idle class always | |
3591 | * returns a non-NULL p: | |
3592 | */ | |
3593 | class = class->next; | |
3594 | } | |
3595 | } | |
1da177e4 | 3596 | |
dd41f596 IM |
3597 | /* |
3598 | * schedule() is the main scheduler function. | |
3599 | */ | |
3600 | asmlinkage void __sched schedule(void) | |
3601 | { | |
3602 | struct task_struct *prev, *next; | |
3603 | long *switch_count; | |
3604 | struct rq *rq; | |
dd41f596 IM |
3605 | int cpu; |
3606 | ||
3607 | need_resched: | |
3608 | preempt_disable(); | |
3609 | cpu = smp_processor_id(); | |
3610 | rq = cpu_rq(cpu); | |
3611 | rcu_qsctr_inc(cpu); | |
3612 | prev = rq->curr; | |
3613 | switch_count = &prev->nivcsw; | |
3614 | ||
3615 | release_kernel_lock(prev); | |
3616 | need_resched_nonpreemptible: | |
3617 | ||
3618 | schedule_debug(prev); | |
1da177e4 | 3619 | |
1e819950 IM |
3620 | /* |
3621 | * Do the rq-clock update outside the rq lock: | |
3622 | */ | |
3623 | local_irq_disable(); | |
c1b3da3e | 3624 | __update_rq_clock(rq); |
1e819950 IM |
3625 | spin_lock(&rq->lock); |
3626 | clear_tsk_need_resched(prev); | |
1da177e4 | 3627 | |
1da177e4 | 3628 | if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) { |
1da177e4 | 3629 | if (unlikely((prev->state & TASK_INTERRUPTIBLE) && |
dd41f596 | 3630 | unlikely(signal_pending(prev)))) { |
1da177e4 | 3631 | prev->state = TASK_RUNNING; |
dd41f596 | 3632 | } else { |
2e1cb74a | 3633 | deactivate_task(rq, prev, 1); |
1da177e4 | 3634 | } |
dd41f596 | 3635 | switch_count = &prev->nvcsw; |
1da177e4 LT |
3636 | } |
3637 | ||
f65eda4f SR |
3638 | schedule_balance_rt(rq, prev); |
3639 | ||
dd41f596 | 3640 | if (unlikely(!rq->nr_running)) |
1da177e4 | 3641 | idle_balance(cpu, rq); |
1da177e4 | 3642 | |
31ee529c | 3643 | prev->sched_class->put_prev_task(rq, prev); |
ff95f3df | 3644 | next = pick_next_task(rq, prev); |
1da177e4 LT |
3645 | |
3646 | sched_info_switch(prev, next); | |
dd41f596 | 3647 | |
1da177e4 | 3648 | if (likely(prev != next)) { |
1da177e4 LT |
3649 | rq->nr_switches++; |
3650 | rq->curr = next; | |
3651 | ++*switch_count; | |
3652 | ||
dd41f596 | 3653 | context_switch(rq, prev, next); /* unlocks the rq */ |
1da177e4 LT |
3654 | } else |
3655 | spin_unlock_irq(&rq->lock); | |
3656 | ||
dd41f596 IM |
3657 | if (unlikely(reacquire_kernel_lock(current) < 0)) { |
3658 | cpu = smp_processor_id(); | |
3659 | rq = cpu_rq(cpu); | |
1da177e4 | 3660 | goto need_resched_nonpreemptible; |
dd41f596 | 3661 | } |
1da177e4 LT |
3662 | preempt_enable_no_resched(); |
3663 | if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) | |
3664 | goto need_resched; | |
3665 | } | |
1da177e4 LT |
3666 | EXPORT_SYMBOL(schedule); |
3667 | ||
3668 | #ifdef CONFIG_PREEMPT | |
3669 | /* | |
2ed6e34f | 3670 | * this is the entry point to schedule() from in-kernel preemption |
41a2d6cf | 3671 | * off of preempt_enable. Kernel preemptions off return from interrupt |
1da177e4 LT |
3672 | * occur there and call schedule directly. |
3673 | */ | |
3674 | asmlinkage void __sched preempt_schedule(void) | |
3675 | { | |
3676 | struct thread_info *ti = current_thread_info(); | |
3677 | #ifdef CONFIG_PREEMPT_BKL | |
3678 | struct task_struct *task = current; | |
3679 | int saved_lock_depth; | |
3680 | #endif | |
3681 | /* | |
3682 | * If there is a non-zero preempt_count or interrupts are disabled, | |
41a2d6cf | 3683 | * we do not want to preempt the current task. Just return.. |
1da177e4 | 3684 | */ |
beed33a8 | 3685 | if (likely(ti->preempt_count || irqs_disabled())) |
1da177e4 LT |
3686 | return; |
3687 | ||
3a5c359a AK |
3688 | do { |
3689 | add_preempt_count(PREEMPT_ACTIVE); | |
3690 | ||
3691 | /* | |
3692 | * We keep the big kernel semaphore locked, but we | |
3693 | * clear ->lock_depth so that schedule() doesnt | |
3694 | * auto-release the semaphore: | |
3695 | */ | |
1da177e4 | 3696 | #ifdef CONFIG_PREEMPT_BKL |
3a5c359a AK |
3697 | saved_lock_depth = task->lock_depth; |
3698 | task->lock_depth = -1; | |
1da177e4 | 3699 | #endif |
3a5c359a | 3700 | schedule(); |
1da177e4 | 3701 | #ifdef CONFIG_PREEMPT_BKL |
3a5c359a | 3702 | task->lock_depth = saved_lock_depth; |
1da177e4 | 3703 | #endif |
3a5c359a | 3704 | sub_preempt_count(PREEMPT_ACTIVE); |
1da177e4 | 3705 | |
3a5c359a AK |
3706 | /* |
3707 | * Check again in case we missed a preemption opportunity | |
3708 | * between schedule and now. | |
3709 | */ | |
3710 | barrier(); | |
3711 | } while (unlikely(test_thread_flag(TIF_NEED_RESCHED))); | |
1da177e4 | 3712 | } |
1da177e4 LT |
3713 | EXPORT_SYMBOL(preempt_schedule); |
3714 | ||
3715 | /* | |
2ed6e34f | 3716 | * this is the entry point to schedule() from kernel preemption |
1da177e4 LT |
3717 | * off of irq context. |
3718 | * Note, that this is called and return with irqs disabled. This will | |
3719 | * protect us against recursive calling from irq. | |
3720 | */ | |
3721 | asmlinkage void __sched preempt_schedule_irq(void) | |
3722 | { | |
3723 | struct thread_info *ti = current_thread_info(); | |
3724 | #ifdef CONFIG_PREEMPT_BKL | |
3725 | struct task_struct *task = current; | |
3726 | int saved_lock_depth; | |
3727 | #endif | |
2ed6e34f | 3728 | /* Catch callers which need to be fixed */ |
1da177e4 LT |
3729 | BUG_ON(ti->preempt_count || !irqs_disabled()); |
3730 | ||
3a5c359a AK |
3731 | do { |
3732 | add_preempt_count(PREEMPT_ACTIVE); | |
3733 | ||
3734 | /* | |
3735 | * We keep the big kernel semaphore locked, but we | |
3736 | * clear ->lock_depth so that schedule() doesnt | |
3737 | * auto-release the semaphore: | |
3738 | */ | |
1da177e4 | 3739 | #ifdef CONFIG_PREEMPT_BKL |
3a5c359a AK |
3740 | saved_lock_depth = task->lock_depth; |
3741 | task->lock_depth = -1; | |
1da177e4 | 3742 | #endif |
3a5c359a AK |
3743 | local_irq_enable(); |
3744 | schedule(); | |
3745 | local_irq_disable(); | |
1da177e4 | 3746 | #ifdef CONFIG_PREEMPT_BKL |
3a5c359a | 3747 | task->lock_depth = saved_lock_depth; |
1da177e4 | 3748 | #endif |
3a5c359a | 3749 | sub_preempt_count(PREEMPT_ACTIVE); |
1da177e4 | 3750 | |
3a5c359a AK |
3751 | /* |
3752 | * Check again in case we missed a preemption opportunity | |
3753 | * between schedule and now. | |
3754 | */ | |
3755 | barrier(); | |
3756 | } while (unlikely(test_thread_flag(TIF_NEED_RESCHED))); | |
1da177e4 LT |
3757 | } |
3758 | ||
3759 | #endif /* CONFIG_PREEMPT */ | |
3760 | ||
95cdf3b7 IM |
3761 | int default_wake_function(wait_queue_t *curr, unsigned mode, int sync, |
3762 | void *key) | |
1da177e4 | 3763 | { |
48f24c4d | 3764 | return try_to_wake_up(curr->private, mode, sync); |
1da177e4 | 3765 | } |
1da177e4 LT |
3766 | EXPORT_SYMBOL(default_wake_function); |
3767 | ||
3768 | /* | |
41a2d6cf IM |
3769 | * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just |
3770 | * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve | |
1da177e4 LT |
3771 | * number) then we wake all the non-exclusive tasks and one exclusive task. |
3772 | * | |
3773 | * There are circumstances in which we can try to wake a task which has already | |
41a2d6cf | 3774 | * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns |
1da177e4 LT |
3775 | * zero in this (rare) case, and we handle it by continuing to scan the queue. |
3776 | */ | |
3777 | static void __wake_up_common(wait_queue_head_t *q, unsigned int mode, | |
3778 | int nr_exclusive, int sync, void *key) | |
3779 | { | |
2e45874c | 3780 | wait_queue_t *curr, *next; |
1da177e4 | 3781 | |
2e45874c | 3782 | list_for_each_entry_safe(curr, next, &q->task_list, task_list) { |
48f24c4d IM |
3783 | unsigned flags = curr->flags; |
3784 | ||
1da177e4 | 3785 | if (curr->func(curr, mode, sync, key) && |
48f24c4d | 3786 | (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive) |
1da177e4 LT |
3787 | break; |
3788 | } | |
3789 | } | |
3790 | ||
3791 | /** | |
3792 | * __wake_up - wake up threads blocked on a waitqueue. | |
3793 | * @q: the waitqueue | |
3794 | * @mode: which threads | |
3795 | * @nr_exclusive: how many wake-one or wake-many threads to wake up | |
67be2dd1 | 3796 | * @key: is directly passed to the wakeup function |
1da177e4 LT |
3797 | */ |
3798 | void fastcall __wake_up(wait_queue_head_t *q, unsigned int mode, | |
95cdf3b7 | 3799 | int nr_exclusive, void *key) |
1da177e4 LT |
3800 | { |
3801 | unsigned long flags; | |
3802 | ||
3803 | spin_lock_irqsave(&q->lock, flags); | |
3804 | __wake_up_common(q, mode, nr_exclusive, 0, key); | |
3805 | spin_unlock_irqrestore(&q->lock, flags); | |
3806 | } | |
1da177e4 LT |
3807 | EXPORT_SYMBOL(__wake_up); |
3808 | ||
3809 | /* | |
3810 | * Same as __wake_up but called with the spinlock in wait_queue_head_t held. | |
3811 | */ | |
3812 | void fastcall __wake_up_locked(wait_queue_head_t *q, unsigned int mode) | |
3813 | { | |
3814 | __wake_up_common(q, mode, 1, 0, NULL); | |
3815 | } | |
3816 | ||
3817 | /** | |
67be2dd1 | 3818 | * __wake_up_sync - wake up threads blocked on a waitqueue. |
1da177e4 LT |
3819 | * @q: the waitqueue |
3820 | * @mode: which threads | |
3821 | * @nr_exclusive: how many wake-one or wake-many threads to wake up | |
3822 | * | |
3823 | * The sync wakeup differs that the waker knows that it will schedule | |
3824 | * away soon, so while the target thread will be woken up, it will not | |
3825 | * be migrated to another CPU - ie. the two threads are 'synchronized' | |
3826 | * with each other. This can prevent needless bouncing between CPUs. | |
3827 | * | |
3828 | * On UP it can prevent extra preemption. | |
3829 | */ | |
95cdf3b7 IM |
3830 | void fastcall |
3831 | __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive) | |
1da177e4 LT |
3832 | { |
3833 | unsigned long flags; | |
3834 | int sync = 1; | |
3835 | ||
3836 | if (unlikely(!q)) | |
3837 | return; | |
3838 | ||
3839 | if (unlikely(!nr_exclusive)) | |
3840 | sync = 0; | |
3841 | ||
3842 | spin_lock_irqsave(&q->lock, flags); | |
3843 | __wake_up_common(q, mode, nr_exclusive, sync, NULL); | |
3844 | spin_unlock_irqrestore(&q->lock, flags); | |
3845 | } | |
3846 | EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */ | |
3847 | ||
b15136e9 | 3848 | void complete(struct completion *x) |
1da177e4 LT |
3849 | { |
3850 | unsigned long flags; | |
3851 | ||
3852 | spin_lock_irqsave(&x->wait.lock, flags); | |
3853 | x->done++; | |
3854 | __wake_up_common(&x->wait, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, | |
3855 | 1, 0, NULL); | |
3856 | spin_unlock_irqrestore(&x->wait.lock, flags); | |
3857 | } | |
3858 | EXPORT_SYMBOL(complete); | |
3859 | ||
b15136e9 | 3860 | void complete_all(struct completion *x) |
1da177e4 LT |
3861 | { |
3862 | unsigned long flags; | |
3863 | ||
3864 | spin_lock_irqsave(&x->wait.lock, flags); | |
3865 | x->done += UINT_MAX/2; | |
3866 | __wake_up_common(&x->wait, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, | |
3867 | 0, 0, NULL); | |
3868 | spin_unlock_irqrestore(&x->wait.lock, flags); | |
3869 | } | |
3870 | EXPORT_SYMBOL(complete_all); | |
3871 | ||
8cbbe86d AK |
3872 | static inline long __sched |
3873 | do_wait_for_common(struct completion *x, long timeout, int state) | |
1da177e4 | 3874 | { |
1da177e4 LT |
3875 | if (!x->done) { |
3876 | DECLARE_WAITQUEUE(wait, current); | |
3877 | ||
3878 | wait.flags |= WQ_FLAG_EXCLUSIVE; | |
3879 | __add_wait_queue_tail(&x->wait, &wait); | |
3880 | do { | |
8cbbe86d AK |
3881 | if (state == TASK_INTERRUPTIBLE && |
3882 | signal_pending(current)) { | |
3883 | __remove_wait_queue(&x->wait, &wait); | |
3884 | return -ERESTARTSYS; | |
3885 | } | |
3886 | __set_current_state(state); | |
1da177e4 LT |
3887 | spin_unlock_irq(&x->wait.lock); |
3888 | timeout = schedule_timeout(timeout); | |
3889 | spin_lock_irq(&x->wait.lock); | |
3890 | if (!timeout) { | |
3891 | __remove_wait_queue(&x->wait, &wait); | |
8cbbe86d | 3892 | return timeout; |
1da177e4 LT |
3893 | } |
3894 | } while (!x->done); | |
3895 | __remove_wait_queue(&x->wait, &wait); | |
3896 | } | |
3897 | x->done--; | |
1da177e4 LT |
3898 | return timeout; |
3899 | } | |
1da177e4 | 3900 | |
8cbbe86d AK |
3901 | static long __sched |
3902 | wait_for_common(struct completion *x, long timeout, int state) | |
1da177e4 | 3903 | { |
1da177e4 LT |
3904 | might_sleep(); |
3905 | ||
3906 | spin_lock_irq(&x->wait.lock); | |
8cbbe86d | 3907 | timeout = do_wait_for_common(x, timeout, state); |
1da177e4 | 3908 | spin_unlock_irq(&x->wait.lock); |
8cbbe86d AK |
3909 | return timeout; |
3910 | } | |
1da177e4 | 3911 | |
b15136e9 | 3912 | void __sched wait_for_completion(struct completion *x) |
8cbbe86d AK |
3913 | { |
3914 | wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE); | |
1da177e4 | 3915 | } |
8cbbe86d | 3916 | EXPORT_SYMBOL(wait_for_completion); |
1da177e4 | 3917 | |
b15136e9 | 3918 | unsigned long __sched |
8cbbe86d | 3919 | wait_for_completion_timeout(struct completion *x, unsigned long timeout) |
1da177e4 | 3920 | { |
8cbbe86d | 3921 | return wait_for_common(x, timeout, TASK_UNINTERRUPTIBLE); |
1da177e4 | 3922 | } |
8cbbe86d | 3923 | EXPORT_SYMBOL(wait_for_completion_timeout); |
1da177e4 | 3924 | |
8cbbe86d | 3925 | int __sched wait_for_completion_interruptible(struct completion *x) |
0fec171c | 3926 | { |
51e97990 AK |
3927 | long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_INTERRUPTIBLE); |
3928 | if (t == -ERESTARTSYS) | |
3929 | return t; | |
3930 | return 0; | |
0fec171c | 3931 | } |
8cbbe86d | 3932 | EXPORT_SYMBOL(wait_for_completion_interruptible); |
1da177e4 | 3933 | |
b15136e9 | 3934 | unsigned long __sched |
8cbbe86d AK |
3935 | wait_for_completion_interruptible_timeout(struct completion *x, |
3936 | unsigned long timeout) | |
0fec171c | 3937 | { |
8cbbe86d | 3938 | return wait_for_common(x, timeout, TASK_INTERRUPTIBLE); |
0fec171c | 3939 | } |
8cbbe86d | 3940 | EXPORT_SYMBOL(wait_for_completion_interruptible_timeout); |
1da177e4 | 3941 | |
8cbbe86d AK |
3942 | static long __sched |
3943 | sleep_on_common(wait_queue_head_t *q, int state, long timeout) | |
1da177e4 | 3944 | { |
0fec171c IM |
3945 | unsigned long flags; |
3946 | wait_queue_t wait; | |
3947 | ||
3948 | init_waitqueue_entry(&wait, current); | |
1da177e4 | 3949 | |
8cbbe86d | 3950 | __set_current_state(state); |
1da177e4 | 3951 | |
8cbbe86d AK |
3952 | spin_lock_irqsave(&q->lock, flags); |
3953 | __add_wait_queue(q, &wait); | |
3954 | spin_unlock(&q->lock); | |
3955 | timeout = schedule_timeout(timeout); | |
3956 | spin_lock_irq(&q->lock); | |
3957 | __remove_wait_queue(q, &wait); | |
3958 | spin_unlock_irqrestore(&q->lock, flags); | |
3959 | ||
3960 | return timeout; | |
3961 | } | |
3962 | ||
3963 | void __sched interruptible_sleep_on(wait_queue_head_t *q) | |
3964 | { | |
3965 | sleep_on_common(q, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); | |
1da177e4 | 3966 | } |
1da177e4 LT |
3967 | EXPORT_SYMBOL(interruptible_sleep_on); |
3968 | ||
0fec171c | 3969 | long __sched |
95cdf3b7 | 3970 | interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout) |
1da177e4 | 3971 | { |
8cbbe86d | 3972 | return sleep_on_common(q, TASK_INTERRUPTIBLE, timeout); |
1da177e4 | 3973 | } |
1da177e4 LT |
3974 | EXPORT_SYMBOL(interruptible_sleep_on_timeout); |
3975 | ||
0fec171c | 3976 | void __sched sleep_on(wait_queue_head_t *q) |
1da177e4 | 3977 | { |
8cbbe86d | 3978 | sleep_on_common(q, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); |
1da177e4 | 3979 | } |
1da177e4 LT |
3980 | EXPORT_SYMBOL(sleep_on); |
3981 | ||
0fec171c | 3982 | long __sched sleep_on_timeout(wait_queue_head_t *q, long timeout) |
1da177e4 | 3983 | { |
8cbbe86d | 3984 | return sleep_on_common(q, TASK_UNINTERRUPTIBLE, timeout); |
1da177e4 | 3985 | } |
1da177e4 LT |
3986 | EXPORT_SYMBOL(sleep_on_timeout); |
3987 | ||
b29739f9 IM |
3988 | #ifdef CONFIG_RT_MUTEXES |
3989 | ||
3990 | /* | |
3991 | * rt_mutex_setprio - set the current priority of a task | |
3992 | * @p: task | |
3993 | * @prio: prio value (kernel-internal form) | |
3994 | * | |
3995 | * This function changes the 'effective' priority of a task. It does | |
3996 | * not touch ->normal_prio like __setscheduler(). | |
3997 | * | |
3998 | * Used by the rt_mutex code to implement priority inheritance logic. | |
3999 | */ | |
36c8b586 | 4000 | void rt_mutex_setprio(struct task_struct *p, int prio) |
b29739f9 IM |
4001 | { |
4002 | unsigned long flags; | |
83b699ed | 4003 | int oldprio, on_rq, running; |
70b97a7f | 4004 | struct rq *rq; |
b29739f9 IM |
4005 | |
4006 | BUG_ON(prio < 0 || prio > MAX_PRIO); | |
4007 | ||
4008 | rq = task_rq_lock(p, &flags); | |
a8e504d2 | 4009 | update_rq_clock(rq); |
b29739f9 | 4010 | |
d5f9f942 | 4011 | oldprio = p->prio; |
dd41f596 | 4012 | on_rq = p->se.on_rq; |
051a1d1a | 4013 | running = task_current(rq, p); |
83b699ed | 4014 | if (on_rq) { |
69be72c1 | 4015 | dequeue_task(rq, p, 0); |
83b699ed SV |
4016 | if (running) |
4017 | p->sched_class->put_prev_task(rq, p); | |
4018 | } | |
dd41f596 IM |
4019 | |
4020 | if (rt_prio(prio)) | |
4021 | p->sched_class = &rt_sched_class; | |
4022 | else | |
4023 | p->sched_class = &fair_sched_class; | |
4024 | ||
b29739f9 IM |
4025 | p->prio = prio; |
4026 | ||
dd41f596 | 4027 | if (on_rq) { |
83b699ed SV |
4028 | if (running) |
4029 | p->sched_class->set_curr_task(rq); | |
8159f87e | 4030 | enqueue_task(rq, p, 0); |
b29739f9 IM |
4031 | /* |
4032 | * Reschedule if we are currently running on this runqueue and | |
d5f9f942 AM |
4033 | * our priority decreased, or if we are not currently running on |
4034 | * this runqueue and our priority is higher than the current's | |
b29739f9 | 4035 | */ |
83b699ed | 4036 | if (running) { |
d5f9f942 AM |
4037 | if (p->prio > oldprio) |
4038 | resched_task(rq->curr); | |
dd41f596 IM |
4039 | } else { |
4040 | check_preempt_curr(rq, p); | |
4041 | } | |
b29739f9 IM |
4042 | } |
4043 | task_rq_unlock(rq, &flags); | |
4044 | } | |
4045 | ||
4046 | #endif | |
4047 | ||
36c8b586 | 4048 | void set_user_nice(struct task_struct *p, long nice) |
1da177e4 | 4049 | { |
dd41f596 | 4050 | int old_prio, delta, on_rq; |
1da177e4 | 4051 | unsigned long flags; |
70b97a7f | 4052 | struct rq *rq; |
1da177e4 LT |
4053 | |
4054 | if (TASK_NICE(p) == nice || nice < -20 || nice > 19) | |
4055 | return; | |
4056 | /* | |
4057 | * We have to be careful, if called from sys_setpriority(), | |
4058 | * the task might be in the middle of scheduling on another CPU. | |
4059 | */ | |
4060 | rq = task_rq_lock(p, &flags); | |
a8e504d2 | 4061 | update_rq_clock(rq); |
1da177e4 LT |
4062 | /* |
4063 | * The RT priorities are set via sched_setscheduler(), but we still | |
4064 | * allow the 'normal' nice value to be set - but as expected | |
4065 | * it wont have any effect on scheduling until the task is | |
dd41f596 | 4066 | * SCHED_FIFO/SCHED_RR: |
1da177e4 | 4067 | */ |
e05606d3 | 4068 | if (task_has_rt_policy(p)) { |
1da177e4 LT |
4069 | p->static_prio = NICE_TO_PRIO(nice); |
4070 | goto out_unlock; | |
4071 | } | |
dd41f596 | 4072 | on_rq = p->se.on_rq; |
58e2d4ca | 4073 | if (on_rq) |
69be72c1 | 4074 | dequeue_task(rq, p, 0); |
1da177e4 | 4075 | |
1da177e4 | 4076 | p->static_prio = NICE_TO_PRIO(nice); |
2dd73a4f | 4077 | set_load_weight(p); |
b29739f9 IM |
4078 | old_prio = p->prio; |
4079 | p->prio = effective_prio(p); | |
4080 | delta = p->prio - old_prio; | |
1da177e4 | 4081 | |
dd41f596 | 4082 | if (on_rq) { |
8159f87e | 4083 | enqueue_task(rq, p, 0); |
1da177e4 | 4084 | /* |
d5f9f942 AM |
4085 | * If the task increased its priority or is running and |
4086 | * lowered its priority, then reschedule its CPU: | |
1da177e4 | 4087 | */ |
d5f9f942 | 4088 | if (delta < 0 || (delta > 0 && task_running(rq, p))) |
1da177e4 LT |
4089 | resched_task(rq->curr); |
4090 | } | |
4091 | out_unlock: | |
4092 | task_rq_unlock(rq, &flags); | |
4093 | } | |
1da177e4 LT |
4094 | EXPORT_SYMBOL(set_user_nice); |
4095 | ||
e43379f1 MM |
4096 | /* |
4097 | * can_nice - check if a task can reduce its nice value | |
4098 | * @p: task | |
4099 | * @nice: nice value | |
4100 | */ | |
36c8b586 | 4101 | int can_nice(const struct task_struct *p, const int nice) |
e43379f1 | 4102 | { |
024f4747 MM |
4103 | /* convert nice value [19,-20] to rlimit style value [1,40] */ |
4104 | int nice_rlim = 20 - nice; | |
48f24c4d | 4105 | |
e43379f1 MM |
4106 | return (nice_rlim <= p->signal->rlim[RLIMIT_NICE].rlim_cur || |
4107 | capable(CAP_SYS_NICE)); | |
4108 | } | |
4109 | ||
1da177e4 LT |
4110 | #ifdef __ARCH_WANT_SYS_NICE |
4111 | ||
4112 | /* | |
4113 | * sys_nice - change the priority of the current process. | |
4114 | * @increment: priority increment | |
4115 | * | |
4116 | * sys_setpriority is a more generic, but much slower function that | |
4117 | * does similar things. | |
4118 | */ | |
4119 | asmlinkage long sys_nice(int increment) | |
4120 | { | |
48f24c4d | 4121 | long nice, retval; |
1da177e4 LT |
4122 | |
4123 | /* | |
4124 | * Setpriority might change our priority at the same moment. | |
4125 | * We don't have to worry. Conceptually one call occurs first | |
4126 | * and we have a single winner. | |
4127 | */ | |
e43379f1 MM |
4128 | if (increment < -40) |
4129 | increment = -40; | |
1da177e4 LT |
4130 | if (increment > 40) |
4131 | increment = 40; | |
4132 | ||
4133 | nice = PRIO_TO_NICE(current->static_prio) + increment; | |
4134 | if (nice < -20) | |
4135 | nice = -20; | |
4136 | if (nice > 19) | |
4137 | nice = 19; | |
4138 | ||
e43379f1 MM |
4139 | if (increment < 0 && !can_nice(current, nice)) |
4140 | return -EPERM; | |
4141 | ||
1da177e4 LT |
4142 | retval = security_task_setnice(current, nice); |
4143 | if (retval) | |
4144 | return retval; | |
4145 | ||
4146 | set_user_nice(current, nice); | |
4147 | return 0; | |
4148 | } | |
4149 | ||
4150 | #endif | |
4151 | ||
4152 | /** | |
4153 | * task_prio - return the priority value of a given task. | |
4154 | * @p: the task in question. | |
4155 | * | |
4156 | * This is the priority value as seen by users in /proc. | |
4157 | * RT tasks are offset by -200. Normal tasks are centered | |
4158 | * around 0, value goes from -16 to +15. | |
4159 | */ | |
36c8b586 | 4160 | int task_prio(const struct task_struct *p) |
1da177e4 LT |
4161 | { |
4162 | return p->prio - MAX_RT_PRIO; | |
4163 | } | |
4164 | ||
4165 | /** | |
4166 | * task_nice - return the nice value of a given task. | |
4167 | * @p: the task in question. | |
4168 | */ | |
36c8b586 | 4169 | int task_nice(const struct task_struct *p) |
1da177e4 LT |
4170 | { |
4171 | return TASK_NICE(p); | |
4172 | } | |
1da177e4 | 4173 | EXPORT_SYMBOL_GPL(task_nice); |
1da177e4 LT |
4174 | |
4175 | /** | |
4176 | * idle_cpu - is a given cpu idle currently? | |
4177 | * @cpu: the processor in question. | |
4178 | */ | |
4179 | int idle_cpu(int cpu) | |
4180 | { | |
4181 | return cpu_curr(cpu) == cpu_rq(cpu)->idle; | |
4182 | } | |
4183 | ||
1da177e4 LT |
4184 | /** |
4185 | * idle_task - return the idle task for a given cpu. | |
4186 | * @cpu: the processor in question. | |
4187 | */ | |
36c8b586 | 4188 | struct task_struct *idle_task(int cpu) |
1da177e4 LT |
4189 | { |
4190 | return cpu_rq(cpu)->idle; | |
4191 | } | |
4192 | ||
4193 | /** | |
4194 | * find_process_by_pid - find a process with a matching PID value. | |
4195 | * @pid: the pid in question. | |
4196 | */ | |
a9957449 | 4197 | static struct task_struct *find_process_by_pid(pid_t pid) |
1da177e4 | 4198 | { |
228ebcbe | 4199 | return pid ? find_task_by_vpid(pid) : current; |
1da177e4 LT |
4200 | } |
4201 | ||
4202 | /* Actually do priority change: must hold rq lock. */ | |
dd41f596 IM |
4203 | static void |
4204 | __setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio) | |
1da177e4 | 4205 | { |
dd41f596 | 4206 | BUG_ON(p->se.on_rq); |
48f24c4d | 4207 | |
1da177e4 | 4208 | p->policy = policy; |
dd41f596 IM |
4209 | switch (p->policy) { |
4210 | case SCHED_NORMAL: | |
4211 | case SCHED_BATCH: | |
4212 | case SCHED_IDLE: | |
4213 | p->sched_class = &fair_sched_class; | |
4214 | break; | |
4215 | case SCHED_FIFO: | |
4216 | case SCHED_RR: | |
4217 | p->sched_class = &rt_sched_class; | |
4218 | break; | |
4219 | } | |
4220 | ||
1da177e4 | 4221 | p->rt_priority = prio; |
b29739f9 IM |
4222 | p->normal_prio = normal_prio(p); |
4223 | /* we are holding p->pi_lock already */ | |
4224 | p->prio = rt_mutex_getprio(p); | |
2dd73a4f | 4225 | set_load_weight(p); |
1da177e4 LT |
4226 | } |
4227 | ||
4228 | /** | |
72fd4a35 | 4229 | * sched_setscheduler - change the scheduling policy and/or RT priority of a thread. |
1da177e4 LT |
4230 | * @p: the task in question. |
4231 | * @policy: new policy. | |
4232 | * @param: structure containing the new RT priority. | |
5fe1d75f | 4233 | * |
72fd4a35 | 4234 | * NOTE that the task may be already dead. |
1da177e4 | 4235 | */ |
95cdf3b7 IM |
4236 | int sched_setscheduler(struct task_struct *p, int policy, |
4237 | struct sched_param *param) | |
1da177e4 | 4238 | { |
83b699ed | 4239 | int retval, oldprio, oldpolicy = -1, on_rq, running; |
1da177e4 | 4240 | unsigned long flags; |
70b97a7f | 4241 | struct rq *rq; |
1da177e4 | 4242 | |
66e5393a SR |
4243 | /* may grab non-irq protected spin_locks */ |
4244 | BUG_ON(in_interrupt()); | |
1da177e4 LT |
4245 | recheck: |
4246 | /* double check policy once rq lock held */ | |
4247 | if (policy < 0) | |
4248 | policy = oldpolicy = p->policy; | |
4249 | else if (policy != SCHED_FIFO && policy != SCHED_RR && | |
dd41f596 IM |
4250 | policy != SCHED_NORMAL && policy != SCHED_BATCH && |
4251 | policy != SCHED_IDLE) | |
b0a9499c | 4252 | return -EINVAL; |
1da177e4 LT |
4253 | /* |
4254 | * Valid priorities for SCHED_FIFO and SCHED_RR are | |
dd41f596 IM |
4255 | * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL, |
4256 | * SCHED_BATCH and SCHED_IDLE is 0. | |
1da177e4 LT |
4257 | */ |
4258 | if (param->sched_priority < 0 || | |
95cdf3b7 | 4259 | (p->mm && param->sched_priority > MAX_USER_RT_PRIO-1) || |
d46523ea | 4260 | (!p->mm && param->sched_priority > MAX_RT_PRIO-1)) |
1da177e4 | 4261 | return -EINVAL; |
e05606d3 | 4262 | if (rt_policy(policy) != (param->sched_priority != 0)) |
1da177e4 LT |
4263 | return -EINVAL; |
4264 | ||
37e4ab3f OC |
4265 | /* |
4266 | * Allow unprivileged RT tasks to decrease priority: | |
4267 | */ | |
4268 | if (!capable(CAP_SYS_NICE)) { | |
e05606d3 | 4269 | if (rt_policy(policy)) { |
8dc3e909 | 4270 | unsigned long rlim_rtprio; |
8dc3e909 ON |
4271 | |
4272 | if (!lock_task_sighand(p, &flags)) | |
4273 | return -ESRCH; | |
4274 | rlim_rtprio = p->signal->rlim[RLIMIT_RTPRIO].rlim_cur; | |
4275 | unlock_task_sighand(p, &flags); | |
4276 | ||
4277 | /* can't set/change the rt policy */ | |
4278 | if (policy != p->policy && !rlim_rtprio) | |
4279 | return -EPERM; | |
4280 | ||
4281 | /* can't increase priority */ | |
4282 | if (param->sched_priority > p->rt_priority && | |
4283 | param->sched_priority > rlim_rtprio) | |
4284 | return -EPERM; | |
4285 | } | |
dd41f596 IM |
4286 | /* |
4287 | * Like positive nice levels, dont allow tasks to | |
4288 | * move out of SCHED_IDLE either: | |
4289 | */ | |
4290 | if (p->policy == SCHED_IDLE && policy != SCHED_IDLE) | |
4291 | return -EPERM; | |
5fe1d75f | 4292 | |
37e4ab3f OC |
4293 | /* can't change other user's priorities */ |
4294 | if ((current->euid != p->euid) && | |
4295 | (current->euid != p->uid)) | |
4296 | return -EPERM; | |
4297 | } | |
1da177e4 LT |
4298 | |
4299 | retval = security_task_setscheduler(p, policy, param); | |
4300 | if (retval) | |
4301 | return retval; | |
b29739f9 IM |
4302 | /* |
4303 | * make sure no PI-waiters arrive (or leave) while we are | |
4304 | * changing the priority of the task: | |
4305 | */ | |
4306 | spin_lock_irqsave(&p->pi_lock, flags); | |
1da177e4 LT |
4307 | /* |
4308 | * To be able to change p->policy safely, the apropriate | |
4309 | * runqueue lock must be held. | |
4310 | */ | |
b29739f9 | 4311 | rq = __task_rq_lock(p); |
1da177e4 LT |
4312 | /* recheck policy now with rq lock held */ |
4313 | if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) { | |
4314 | policy = oldpolicy = -1; | |
b29739f9 IM |
4315 | __task_rq_unlock(rq); |
4316 | spin_unlock_irqrestore(&p->pi_lock, flags); | |
1da177e4 LT |
4317 | goto recheck; |
4318 | } | |
2daa3577 | 4319 | update_rq_clock(rq); |
dd41f596 | 4320 | on_rq = p->se.on_rq; |
051a1d1a | 4321 | running = task_current(rq, p); |
83b699ed | 4322 | if (on_rq) { |
2e1cb74a | 4323 | deactivate_task(rq, p, 0); |
83b699ed SV |
4324 | if (running) |
4325 | p->sched_class->put_prev_task(rq, p); | |
4326 | } | |
f6b53205 | 4327 | |
1da177e4 | 4328 | oldprio = p->prio; |
dd41f596 | 4329 | __setscheduler(rq, p, policy, param->sched_priority); |
f6b53205 | 4330 | |
dd41f596 | 4331 | if (on_rq) { |
83b699ed SV |
4332 | if (running) |
4333 | p->sched_class->set_curr_task(rq); | |
dd41f596 | 4334 | activate_task(rq, p, 0); |
1da177e4 LT |
4335 | /* |
4336 | * Reschedule if we are currently running on this runqueue and | |
d5f9f942 AM |
4337 | * our priority decreased, or if we are not currently running on |
4338 | * this runqueue and our priority is higher than the current's | |
1da177e4 | 4339 | */ |
83b699ed | 4340 | if (running) { |
d5f9f942 AM |
4341 | if (p->prio > oldprio) |
4342 | resched_task(rq->curr); | |
dd41f596 IM |
4343 | } else { |
4344 | check_preempt_curr(rq, p); | |
4345 | } | |
1da177e4 | 4346 | } |
b29739f9 IM |
4347 | __task_rq_unlock(rq); |
4348 | spin_unlock_irqrestore(&p->pi_lock, flags); | |
4349 | ||
95e02ca9 TG |
4350 | rt_mutex_adjust_pi(p); |
4351 | ||
1da177e4 LT |
4352 | return 0; |
4353 | } | |
4354 | EXPORT_SYMBOL_GPL(sched_setscheduler); | |
4355 | ||
95cdf3b7 IM |
4356 | static int |
4357 | do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param) | |
1da177e4 | 4358 | { |
1da177e4 LT |
4359 | struct sched_param lparam; |
4360 | struct task_struct *p; | |
36c8b586 | 4361 | int retval; |
1da177e4 LT |
4362 | |
4363 | if (!param || pid < 0) | |
4364 | return -EINVAL; | |
4365 | if (copy_from_user(&lparam, param, sizeof(struct sched_param))) | |
4366 | return -EFAULT; | |
5fe1d75f ON |
4367 | |
4368 | rcu_read_lock(); | |
4369 | retval = -ESRCH; | |
1da177e4 | 4370 | p = find_process_by_pid(pid); |
5fe1d75f ON |
4371 | if (p != NULL) |
4372 | retval = sched_setscheduler(p, policy, &lparam); | |
4373 | rcu_read_unlock(); | |
36c8b586 | 4374 | |
1da177e4 LT |
4375 | return retval; |
4376 | } | |
4377 | ||
4378 | /** | |
4379 | * sys_sched_setscheduler - set/change the scheduler policy and RT priority | |
4380 | * @pid: the pid in question. | |
4381 | * @policy: new policy. | |
4382 | * @param: structure containing the new RT priority. | |
4383 | */ | |
41a2d6cf IM |
4384 | asmlinkage long |
4385 | sys_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param) | |
1da177e4 | 4386 | { |
c21761f1 JB |
4387 | /* negative values for policy are not valid */ |
4388 | if (policy < 0) | |
4389 | return -EINVAL; | |
4390 | ||
1da177e4 LT |
4391 | return do_sched_setscheduler(pid, policy, param); |
4392 | } | |
4393 | ||
4394 | /** | |
4395 | * sys_sched_setparam - set/change the RT priority of a thread | |
4396 | * @pid: the pid in question. | |
4397 | * @param: structure containing the new RT priority. | |
4398 | */ | |
4399 | asmlinkage long sys_sched_setparam(pid_t pid, struct sched_param __user *param) | |
4400 | { | |
4401 | return do_sched_setscheduler(pid, -1, param); | |
4402 | } | |
4403 | ||
4404 | /** | |
4405 | * sys_sched_getscheduler - get the policy (scheduling class) of a thread | |
4406 | * @pid: the pid in question. | |
4407 | */ | |
4408 | asmlinkage long sys_sched_getscheduler(pid_t pid) | |
4409 | { | |
36c8b586 | 4410 | struct task_struct *p; |
3a5c359a | 4411 | int retval; |
1da177e4 LT |
4412 | |
4413 | if (pid < 0) | |
3a5c359a | 4414 | return -EINVAL; |
1da177e4 LT |
4415 | |
4416 | retval = -ESRCH; | |
4417 | read_lock(&tasklist_lock); | |
4418 | p = find_process_by_pid(pid); | |
4419 | if (p) { | |
4420 | retval = security_task_getscheduler(p); | |
4421 | if (!retval) | |
4422 | retval = p->policy; | |
4423 | } | |
4424 | read_unlock(&tasklist_lock); | |
1da177e4 LT |
4425 | return retval; |
4426 | } | |
4427 | ||
4428 | /** | |
4429 | * sys_sched_getscheduler - get the RT priority of a thread | |
4430 | * @pid: the pid in question. | |
4431 | * @param: structure containing the RT priority. | |
4432 | */ | |
4433 | asmlinkage long sys_sched_getparam(pid_t pid, struct sched_param __user *param) | |
4434 | { | |
4435 | struct sched_param lp; | |
36c8b586 | 4436 | struct task_struct *p; |
3a5c359a | 4437 | int retval; |
1da177e4 LT |
4438 | |
4439 | if (!param || pid < 0) | |
3a5c359a | 4440 | return -EINVAL; |
1da177e4 LT |
4441 | |
4442 | read_lock(&tasklist_lock); | |
4443 | p = find_process_by_pid(pid); | |
4444 | retval = -ESRCH; | |
4445 | if (!p) | |
4446 | goto out_unlock; | |
4447 | ||
4448 | retval = security_task_getscheduler(p); | |
4449 | if (retval) | |
4450 | goto out_unlock; | |
4451 | ||
4452 | lp.sched_priority = p->rt_priority; | |
4453 | read_unlock(&tasklist_lock); | |
4454 | ||
4455 | /* | |
4456 | * This one might sleep, we cannot do it with a spinlock held ... | |
4457 | */ | |
4458 | retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0; | |
4459 | ||
1da177e4 LT |
4460 | return retval; |
4461 | ||
4462 | out_unlock: | |
4463 | read_unlock(&tasklist_lock); | |
4464 | return retval; | |
4465 | } | |
4466 | ||
4467 | long sched_setaffinity(pid_t pid, cpumask_t new_mask) | |
4468 | { | |
1da177e4 | 4469 | cpumask_t cpus_allowed; |
36c8b586 IM |
4470 | struct task_struct *p; |
4471 | int retval; | |
1da177e4 | 4472 | |
95402b38 | 4473 | get_online_cpus(); |
1da177e4 LT |
4474 | read_lock(&tasklist_lock); |
4475 | ||
4476 | p = find_process_by_pid(pid); | |
4477 | if (!p) { | |
4478 | read_unlock(&tasklist_lock); | |
95402b38 | 4479 | put_online_cpus(); |
1da177e4 LT |
4480 | return -ESRCH; |
4481 | } | |
4482 | ||
4483 | /* | |
4484 | * It is not safe to call set_cpus_allowed with the | |
41a2d6cf | 4485 | * tasklist_lock held. We will bump the task_struct's |
1da177e4 LT |
4486 | * usage count and then drop tasklist_lock. |
4487 | */ | |
4488 | get_task_struct(p); | |
4489 | read_unlock(&tasklist_lock); | |
4490 | ||
4491 | retval = -EPERM; | |
4492 | if ((current->euid != p->euid) && (current->euid != p->uid) && | |
4493 | !capable(CAP_SYS_NICE)) | |
4494 | goto out_unlock; | |
4495 | ||
e7834f8f DQ |
4496 | retval = security_task_setscheduler(p, 0, NULL); |
4497 | if (retval) | |
4498 | goto out_unlock; | |
4499 | ||
1da177e4 LT |
4500 | cpus_allowed = cpuset_cpus_allowed(p); |
4501 | cpus_and(new_mask, new_mask, cpus_allowed); | |
8707d8b8 | 4502 | again: |
1da177e4 LT |
4503 | retval = set_cpus_allowed(p, new_mask); |
4504 | ||
8707d8b8 PM |
4505 | if (!retval) { |
4506 | cpus_allowed = cpuset_cpus_allowed(p); | |
4507 | if (!cpus_subset(new_mask, cpus_allowed)) { | |
4508 | /* | |
4509 | * We must have raced with a concurrent cpuset | |
4510 | * update. Just reset the cpus_allowed to the | |
4511 | * cpuset's cpus_allowed | |
4512 | */ | |
4513 | new_mask = cpus_allowed; | |
4514 | goto again; | |
4515 | } | |
4516 | } | |
1da177e4 LT |
4517 | out_unlock: |
4518 | put_task_struct(p); | |
95402b38 | 4519 | put_online_cpus(); |
1da177e4 LT |
4520 | return retval; |
4521 | } | |
4522 | ||
4523 | static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len, | |
4524 | cpumask_t *new_mask) | |
4525 | { | |
4526 | if (len < sizeof(cpumask_t)) { | |
4527 | memset(new_mask, 0, sizeof(cpumask_t)); | |
4528 | } else if (len > sizeof(cpumask_t)) { | |
4529 | len = sizeof(cpumask_t); | |
4530 | } | |
4531 | return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0; | |
4532 | } | |
4533 | ||
4534 | /** | |
4535 | * sys_sched_setaffinity - set the cpu affinity of a process | |
4536 | * @pid: pid of the process | |
4537 | * @len: length in bytes of the bitmask pointed to by user_mask_ptr | |
4538 | * @user_mask_ptr: user-space pointer to the new cpu mask | |
4539 | */ | |
4540 | asmlinkage long sys_sched_setaffinity(pid_t pid, unsigned int len, | |
4541 | unsigned long __user *user_mask_ptr) | |
4542 | { | |
4543 | cpumask_t new_mask; | |
4544 | int retval; | |
4545 | ||
4546 | retval = get_user_cpu_mask(user_mask_ptr, len, &new_mask); | |
4547 | if (retval) | |
4548 | return retval; | |
4549 | ||
4550 | return sched_setaffinity(pid, new_mask); | |
4551 | } | |
4552 | ||
4553 | /* | |
4554 | * Represents all cpu's present in the system | |
4555 | * In systems capable of hotplug, this map could dynamically grow | |
4556 | * as new cpu's are detected in the system via any platform specific | |
4557 | * method, such as ACPI for e.g. | |
4558 | */ | |
4559 | ||
4cef0c61 | 4560 | cpumask_t cpu_present_map __read_mostly; |
1da177e4 LT |
4561 | EXPORT_SYMBOL(cpu_present_map); |
4562 | ||
4563 | #ifndef CONFIG_SMP | |
4cef0c61 | 4564 | cpumask_t cpu_online_map __read_mostly = CPU_MASK_ALL; |
e16b38f7 GB |
4565 | EXPORT_SYMBOL(cpu_online_map); |
4566 | ||
4cef0c61 | 4567 | cpumask_t cpu_possible_map __read_mostly = CPU_MASK_ALL; |
e16b38f7 | 4568 | EXPORT_SYMBOL(cpu_possible_map); |
1da177e4 LT |
4569 | #endif |
4570 | ||
4571 | long sched_getaffinity(pid_t pid, cpumask_t *mask) | |
4572 | { | |
36c8b586 | 4573 | struct task_struct *p; |
1da177e4 | 4574 | int retval; |
1da177e4 | 4575 | |
95402b38 | 4576 | get_online_cpus(); |
1da177e4 LT |
4577 | read_lock(&tasklist_lock); |
4578 | ||
4579 | retval = -ESRCH; | |
4580 | p = find_process_by_pid(pid); | |
4581 | if (!p) | |
4582 | goto out_unlock; | |
4583 | ||
e7834f8f DQ |
4584 | retval = security_task_getscheduler(p); |
4585 | if (retval) | |
4586 | goto out_unlock; | |
4587 | ||
2f7016d9 | 4588 | cpus_and(*mask, p->cpus_allowed, cpu_online_map); |
1da177e4 LT |
4589 | |
4590 | out_unlock: | |
4591 | read_unlock(&tasklist_lock); | |
95402b38 | 4592 | put_online_cpus(); |
1da177e4 | 4593 | |
9531b62f | 4594 | return retval; |
1da177e4 LT |
4595 | } |
4596 | ||
4597 | /** | |
4598 | * sys_sched_getaffinity - get the cpu affinity of a process | |
4599 | * @pid: pid of the process | |
4600 | * @len: length in bytes of the bitmask pointed to by user_mask_ptr | |
4601 | * @user_mask_ptr: user-space pointer to hold the current cpu mask | |
4602 | */ | |
4603 | asmlinkage long sys_sched_getaffinity(pid_t pid, unsigned int len, | |
4604 | unsigned long __user *user_mask_ptr) | |
4605 | { | |
4606 | int ret; | |
4607 | cpumask_t mask; | |
4608 | ||
4609 | if (len < sizeof(cpumask_t)) | |
4610 | return -EINVAL; | |
4611 | ||
4612 | ret = sched_getaffinity(pid, &mask); | |
4613 | if (ret < 0) | |
4614 | return ret; | |
4615 | ||
4616 | if (copy_to_user(user_mask_ptr, &mask, sizeof(cpumask_t))) | |
4617 | return -EFAULT; | |
4618 | ||
4619 | return sizeof(cpumask_t); | |
4620 | } | |
4621 | ||
4622 | /** | |
4623 | * sys_sched_yield - yield the current processor to other threads. | |
4624 | * | |
dd41f596 IM |
4625 | * This function yields the current CPU to other tasks. If there are no |
4626 | * other threads running on this CPU then this function will return. | |
1da177e4 LT |
4627 | */ |
4628 | asmlinkage long sys_sched_yield(void) | |
4629 | { | |
70b97a7f | 4630 | struct rq *rq = this_rq_lock(); |
1da177e4 | 4631 | |
2d72376b | 4632 | schedstat_inc(rq, yld_count); |
4530d7ab | 4633 | current->sched_class->yield_task(rq); |
1da177e4 LT |
4634 | |
4635 | /* | |
4636 | * Since we are going to call schedule() anyway, there's | |
4637 | * no need to preempt or enable interrupts: | |
4638 | */ | |
4639 | __release(rq->lock); | |
8a25d5de | 4640 | spin_release(&rq->lock.dep_map, 1, _THIS_IP_); |
1da177e4 LT |
4641 | _raw_spin_unlock(&rq->lock); |
4642 | preempt_enable_no_resched(); | |
4643 | ||
4644 | schedule(); | |
4645 | ||
4646 | return 0; | |
4647 | } | |
4648 | ||
e7b38404 | 4649 | static void __cond_resched(void) |
1da177e4 | 4650 | { |
8e0a43d8 IM |
4651 | #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP |
4652 | __might_sleep(__FILE__, __LINE__); | |
4653 | #endif | |
5bbcfd90 IM |
4654 | /* |
4655 | * The BKS might be reacquired before we have dropped | |
4656 | * PREEMPT_ACTIVE, which could trigger a second | |
4657 | * cond_resched() call. | |
4658 | */ | |
1da177e4 LT |
4659 | do { |
4660 | add_preempt_count(PREEMPT_ACTIVE); | |
4661 | schedule(); | |
4662 | sub_preempt_count(PREEMPT_ACTIVE); | |
4663 | } while (need_resched()); | |
4664 | } | |
4665 | ||
4666 | int __sched cond_resched(void) | |
4667 | { | |
9414232f IM |
4668 | if (need_resched() && !(preempt_count() & PREEMPT_ACTIVE) && |
4669 | system_state == SYSTEM_RUNNING) { | |
1da177e4 LT |
4670 | __cond_resched(); |
4671 | return 1; | |
4672 | } | |
4673 | return 0; | |
4674 | } | |
1da177e4 LT |
4675 | EXPORT_SYMBOL(cond_resched); |
4676 | ||
4677 | /* | |
4678 | * cond_resched_lock() - if a reschedule is pending, drop the given lock, | |
4679 | * call schedule, and on return reacquire the lock. | |
4680 | * | |
41a2d6cf | 4681 | * This works OK both with and without CONFIG_PREEMPT. We do strange low-level |
1da177e4 LT |
4682 | * operations here to prevent schedule() from being called twice (once via |
4683 | * spin_unlock(), once by hand). | |
4684 | */ | |
95cdf3b7 | 4685 | int cond_resched_lock(spinlock_t *lock) |
1da177e4 | 4686 | { |
6df3cecb JK |
4687 | int ret = 0; |
4688 | ||
1da177e4 LT |
4689 | if (need_lockbreak(lock)) { |
4690 | spin_unlock(lock); | |
4691 | cpu_relax(); | |
6df3cecb | 4692 | ret = 1; |
1da177e4 LT |
4693 | spin_lock(lock); |
4694 | } | |
9414232f | 4695 | if (need_resched() && system_state == SYSTEM_RUNNING) { |
8a25d5de | 4696 | spin_release(&lock->dep_map, 1, _THIS_IP_); |
1da177e4 LT |
4697 | _raw_spin_unlock(lock); |
4698 | preempt_enable_no_resched(); | |
4699 | __cond_resched(); | |
6df3cecb | 4700 | ret = 1; |
1da177e4 | 4701 | spin_lock(lock); |
1da177e4 | 4702 | } |
6df3cecb | 4703 | return ret; |
1da177e4 | 4704 | } |
1da177e4 LT |
4705 | EXPORT_SYMBOL(cond_resched_lock); |
4706 | ||
4707 | int __sched cond_resched_softirq(void) | |
4708 | { | |
4709 | BUG_ON(!in_softirq()); | |
4710 | ||
9414232f | 4711 | if (need_resched() && system_state == SYSTEM_RUNNING) { |
98d82567 | 4712 | local_bh_enable(); |
1da177e4 LT |
4713 | __cond_resched(); |
4714 | local_bh_disable(); | |
4715 | return 1; | |
4716 | } | |
4717 | return 0; | |
4718 | } | |
1da177e4 LT |
4719 | EXPORT_SYMBOL(cond_resched_softirq); |
4720 | ||
1da177e4 LT |
4721 | /** |
4722 | * yield - yield the current processor to other threads. | |
4723 | * | |
72fd4a35 | 4724 | * This is a shortcut for kernel-space yielding - it marks the |
1da177e4 LT |
4725 | * thread runnable and calls sys_sched_yield(). |
4726 | */ | |
4727 | void __sched yield(void) | |
4728 | { | |
4729 | set_current_state(TASK_RUNNING); | |
4730 | sys_sched_yield(); | |
4731 | } | |
1da177e4 LT |
4732 | EXPORT_SYMBOL(yield); |
4733 | ||
4734 | /* | |
41a2d6cf | 4735 | * This task is about to go to sleep on IO. Increment rq->nr_iowait so |
1da177e4 LT |
4736 | * that process accounting knows that this is a task in IO wait state. |
4737 | * | |
4738 | * But don't do that if it is a deliberate, throttling IO wait (this task | |
4739 | * has set its backing_dev_info: the queue against which it should throttle) | |
4740 | */ | |
4741 | void __sched io_schedule(void) | |
4742 | { | |
70b97a7f | 4743 | struct rq *rq = &__raw_get_cpu_var(runqueues); |
1da177e4 | 4744 | |
0ff92245 | 4745 | delayacct_blkio_start(); |
1da177e4 LT |
4746 | atomic_inc(&rq->nr_iowait); |
4747 | schedule(); | |
4748 | atomic_dec(&rq->nr_iowait); | |
0ff92245 | 4749 | delayacct_blkio_end(); |
1da177e4 | 4750 | } |
1da177e4 LT |
4751 | EXPORT_SYMBOL(io_schedule); |
4752 | ||
4753 | long __sched io_schedule_timeout(long timeout) | |
4754 | { | |
70b97a7f | 4755 | struct rq *rq = &__raw_get_cpu_var(runqueues); |
1da177e4 LT |
4756 | long ret; |
4757 | ||
0ff92245 | 4758 | delayacct_blkio_start(); |
1da177e4 LT |
4759 | atomic_inc(&rq->nr_iowait); |
4760 | ret = schedule_timeout(timeout); | |
4761 | atomic_dec(&rq->nr_iowait); | |
0ff92245 | 4762 | delayacct_blkio_end(); |
1da177e4 LT |
4763 | return ret; |
4764 | } | |
4765 | ||
4766 | /** | |
4767 | * sys_sched_get_priority_max - return maximum RT priority. | |
4768 | * @policy: scheduling class. | |
4769 | * | |
4770 | * this syscall returns the maximum rt_priority that can be used | |
4771 | * by a given scheduling class. | |
4772 | */ | |
4773 | asmlinkage long sys_sched_get_priority_max(int policy) | |
4774 | { | |
4775 | int ret = -EINVAL; | |
4776 | ||
4777 | switch (policy) { | |
4778 | case SCHED_FIFO: | |
4779 | case SCHED_RR: | |
4780 | ret = MAX_USER_RT_PRIO-1; | |
4781 | break; | |
4782 | case SCHED_NORMAL: | |
b0a9499c | 4783 | case SCHED_BATCH: |
dd41f596 | 4784 | case SCHED_IDLE: |
1da177e4 LT |
4785 | ret = 0; |
4786 | break; | |
4787 | } | |
4788 | return ret; | |
4789 | } | |
4790 | ||
4791 | /** | |
4792 | * sys_sched_get_priority_min - return minimum RT priority. | |
4793 | * @policy: scheduling class. | |
4794 | * | |
4795 | * this syscall returns the minimum rt_priority that can be used | |
4796 | * by a given scheduling class. | |
4797 | */ | |
4798 | asmlinkage long sys_sched_get_priority_min(int policy) | |
4799 | { | |
4800 | int ret = -EINVAL; | |
4801 | ||
4802 | switch (policy) { | |
4803 | case SCHED_FIFO: | |
4804 | case SCHED_RR: | |
4805 | ret = 1; | |
4806 | break; | |
4807 | case SCHED_NORMAL: | |
b0a9499c | 4808 | case SCHED_BATCH: |
dd41f596 | 4809 | case SCHED_IDLE: |
1da177e4 LT |
4810 | ret = 0; |
4811 | } | |
4812 | return ret; | |
4813 | } | |
4814 | ||
4815 | /** | |
4816 | * sys_sched_rr_get_interval - return the default timeslice of a process. | |
4817 | * @pid: pid of the process. | |
4818 | * @interval: userspace pointer to the timeslice value. | |
4819 | * | |
4820 | * this syscall writes the default timeslice value of a given process | |
4821 | * into the user-space timespec buffer. A value of '0' means infinity. | |
4822 | */ | |
4823 | asmlinkage | |
4824 | long sys_sched_rr_get_interval(pid_t pid, struct timespec __user *interval) | |
4825 | { | |
36c8b586 | 4826 | struct task_struct *p; |
a4ec24b4 | 4827 | unsigned int time_slice; |
3a5c359a | 4828 | int retval; |
1da177e4 | 4829 | struct timespec t; |
1da177e4 LT |
4830 | |
4831 | if (pid < 0) | |
3a5c359a | 4832 | return -EINVAL; |
1da177e4 LT |
4833 | |
4834 | retval = -ESRCH; | |
4835 | read_lock(&tasklist_lock); | |
4836 | p = find_process_by_pid(pid); | |
4837 | if (!p) | |
4838 | goto out_unlock; | |
4839 | ||
4840 | retval = security_task_getscheduler(p); | |
4841 | if (retval) | |
4842 | goto out_unlock; | |
4843 | ||
77034937 IM |
4844 | /* |
4845 | * Time slice is 0 for SCHED_FIFO tasks and for SCHED_OTHER | |
4846 | * tasks that are on an otherwise idle runqueue: | |
4847 | */ | |
4848 | time_slice = 0; | |
4849 | if (p->policy == SCHED_RR) { | |
a4ec24b4 | 4850 | time_slice = DEF_TIMESLICE; |
77034937 | 4851 | } else { |
a4ec24b4 DA |
4852 | struct sched_entity *se = &p->se; |
4853 | unsigned long flags; | |
4854 | struct rq *rq; | |
4855 | ||
4856 | rq = task_rq_lock(p, &flags); | |
77034937 IM |
4857 | if (rq->cfs.load.weight) |
4858 | time_slice = NS_TO_JIFFIES(sched_slice(&rq->cfs, se)); | |
a4ec24b4 DA |
4859 | task_rq_unlock(rq, &flags); |
4860 | } | |
1da177e4 | 4861 | read_unlock(&tasklist_lock); |
a4ec24b4 | 4862 | jiffies_to_timespec(time_slice, &t); |
1da177e4 | 4863 | retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0; |
1da177e4 | 4864 | return retval; |
3a5c359a | 4865 | |
1da177e4 LT |
4866 | out_unlock: |
4867 | read_unlock(&tasklist_lock); | |
4868 | return retval; | |
4869 | } | |
4870 | ||
2ed6e34f | 4871 | static const char stat_nam[] = "RSDTtZX"; |
36c8b586 | 4872 | |
82a1fcb9 | 4873 | void sched_show_task(struct task_struct *p) |
1da177e4 | 4874 | { |
1da177e4 | 4875 | unsigned long free = 0; |
36c8b586 | 4876 | unsigned state; |
1da177e4 | 4877 | |
1da177e4 | 4878 | state = p->state ? __ffs(p->state) + 1 : 0; |
cc4ea795 | 4879 | printk(KERN_INFO "%-13.13s %c", p->comm, |
2ed6e34f | 4880 | state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?'); |
4bd77321 | 4881 | #if BITS_PER_LONG == 32 |
1da177e4 | 4882 | if (state == TASK_RUNNING) |
cc4ea795 | 4883 | printk(KERN_CONT " running "); |
1da177e4 | 4884 | else |
cc4ea795 | 4885 | printk(KERN_CONT " %08lx ", thread_saved_pc(p)); |
1da177e4 LT |
4886 | #else |
4887 | if (state == TASK_RUNNING) | |
cc4ea795 | 4888 | printk(KERN_CONT " running task "); |
1da177e4 | 4889 | else |
cc4ea795 | 4890 | printk(KERN_CONT " %016lx ", thread_saved_pc(p)); |
1da177e4 LT |
4891 | #endif |
4892 | #ifdef CONFIG_DEBUG_STACK_USAGE | |
4893 | { | |
10ebffde | 4894 | unsigned long *n = end_of_stack(p); |
1da177e4 LT |
4895 | while (!*n) |
4896 | n++; | |
10ebffde | 4897 | free = (unsigned long)n - (unsigned long)end_of_stack(p); |
1da177e4 LT |
4898 | } |
4899 | #endif | |
ba25f9dc | 4900 | printk(KERN_CONT "%5lu %5d %6d\n", free, |
fcfd50af | 4901 | task_pid_nr(p), task_pid_nr(p->real_parent)); |
1da177e4 LT |
4902 | |
4903 | if (state != TASK_RUNNING) | |
4904 | show_stack(p, NULL); | |
4905 | } | |
4906 | ||
e59e2ae2 | 4907 | void show_state_filter(unsigned long state_filter) |
1da177e4 | 4908 | { |
36c8b586 | 4909 | struct task_struct *g, *p; |
1da177e4 | 4910 | |
4bd77321 IM |
4911 | #if BITS_PER_LONG == 32 |
4912 | printk(KERN_INFO | |
4913 | " task PC stack pid father\n"); | |
1da177e4 | 4914 | #else |
4bd77321 IM |
4915 | printk(KERN_INFO |
4916 | " task PC stack pid father\n"); | |
1da177e4 LT |
4917 | #endif |
4918 | read_lock(&tasklist_lock); | |
4919 | do_each_thread(g, p) { | |
4920 | /* | |
4921 | * reset the NMI-timeout, listing all files on a slow | |
4922 | * console might take alot of time: | |
4923 | */ | |
4924 | touch_nmi_watchdog(); | |
39bc89fd | 4925 | if (!state_filter || (p->state & state_filter)) |
82a1fcb9 | 4926 | sched_show_task(p); |
1da177e4 LT |
4927 | } while_each_thread(g, p); |
4928 | ||
04c9167f JF |
4929 | touch_all_softlockup_watchdogs(); |
4930 | ||
dd41f596 IM |
4931 | #ifdef CONFIG_SCHED_DEBUG |
4932 | sysrq_sched_debug_show(); | |
4933 | #endif | |
1da177e4 | 4934 | read_unlock(&tasklist_lock); |
e59e2ae2 IM |
4935 | /* |
4936 | * Only show locks if all tasks are dumped: | |
4937 | */ | |
4938 | if (state_filter == -1) | |
4939 | debug_show_all_locks(); | |
1da177e4 LT |
4940 | } |
4941 | ||
1df21055 IM |
4942 | void __cpuinit init_idle_bootup_task(struct task_struct *idle) |
4943 | { | |
dd41f596 | 4944 | idle->sched_class = &idle_sched_class; |
1df21055 IM |
4945 | } |
4946 | ||
f340c0d1 IM |
4947 | /** |
4948 | * init_idle - set up an idle thread for a given CPU | |
4949 | * @idle: task in question | |
4950 | * @cpu: cpu the idle task belongs to | |
4951 | * | |
4952 | * NOTE: this function does not set the idle thread's NEED_RESCHED | |
4953 | * flag, to make booting more robust. | |
4954 | */ | |
5c1e1767 | 4955 | void __cpuinit init_idle(struct task_struct *idle, int cpu) |
1da177e4 | 4956 | { |
70b97a7f | 4957 | struct rq *rq = cpu_rq(cpu); |
1da177e4 LT |
4958 | unsigned long flags; |
4959 | ||
dd41f596 IM |
4960 | __sched_fork(idle); |
4961 | idle->se.exec_start = sched_clock(); | |
4962 | ||
b29739f9 | 4963 | idle->prio = idle->normal_prio = MAX_PRIO; |
1da177e4 | 4964 | idle->cpus_allowed = cpumask_of_cpu(cpu); |
dd41f596 | 4965 | __set_task_cpu(idle, cpu); |
1da177e4 LT |
4966 | |
4967 | spin_lock_irqsave(&rq->lock, flags); | |
4968 | rq->curr = rq->idle = idle; | |
4866cde0 NP |
4969 | #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW) |
4970 | idle->oncpu = 1; | |
4971 | #endif | |
1da177e4 LT |
4972 | spin_unlock_irqrestore(&rq->lock, flags); |
4973 | ||
4974 | /* Set the preempt count _outside_ the spinlocks! */ | |
4975 | #if defined(CONFIG_PREEMPT) && !defined(CONFIG_PREEMPT_BKL) | |
a1261f54 | 4976 | task_thread_info(idle)->preempt_count = (idle->lock_depth >= 0); |
1da177e4 | 4977 | #else |
a1261f54 | 4978 | task_thread_info(idle)->preempt_count = 0; |
1da177e4 | 4979 | #endif |
dd41f596 IM |
4980 | /* |
4981 | * The idle tasks have their own, simple scheduling class: | |
4982 | */ | |
4983 | idle->sched_class = &idle_sched_class; | |
1da177e4 LT |
4984 | } |
4985 | ||
4986 | /* | |
4987 | * In a system that switches off the HZ timer nohz_cpu_mask | |
4988 | * indicates which cpus entered this state. This is used | |
4989 | * in the rcu update to wait only for active cpus. For system | |
4990 | * which do not switch off the HZ timer nohz_cpu_mask should | |
4991 | * always be CPU_MASK_NONE. | |
4992 | */ | |
4993 | cpumask_t nohz_cpu_mask = CPU_MASK_NONE; | |
4994 | ||
19978ca6 IM |
4995 | /* |
4996 | * Increase the granularity value when there are more CPUs, | |
4997 | * because with more CPUs the 'effective latency' as visible | |
4998 | * to users decreases. But the relationship is not linear, | |
4999 | * so pick a second-best guess by going with the log2 of the | |
5000 | * number of CPUs. | |
5001 | * | |
5002 | * This idea comes from the SD scheduler of Con Kolivas: | |
5003 | */ | |
5004 | static inline void sched_init_granularity(void) | |
5005 | { | |
5006 | unsigned int factor = 1 + ilog2(num_online_cpus()); | |
5007 | const unsigned long limit = 200000000; | |
5008 | ||
5009 | sysctl_sched_min_granularity *= factor; | |
5010 | if (sysctl_sched_min_granularity > limit) | |
5011 | sysctl_sched_min_granularity = limit; | |
5012 | ||
5013 | sysctl_sched_latency *= factor; | |
5014 | if (sysctl_sched_latency > limit) | |
5015 | sysctl_sched_latency = limit; | |
5016 | ||
5017 | sysctl_sched_wakeup_granularity *= factor; | |
5018 | sysctl_sched_batch_wakeup_granularity *= factor; | |
5019 | } | |
5020 | ||
1da177e4 LT |
5021 | #ifdef CONFIG_SMP |
5022 | /* | |
5023 | * This is how migration works: | |
5024 | * | |
70b97a7f | 5025 | * 1) we queue a struct migration_req structure in the source CPU's |
1da177e4 LT |
5026 | * runqueue and wake up that CPU's migration thread. |
5027 | * 2) we down() the locked semaphore => thread blocks. | |
5028 | * 3) migration thread wakes up (implicitly it forces the migrated | |
5029 | * thread off the CPU) | |
5030 | * 4) it gets the migration request and checks whether the migrated | |
5031 | * task is still in the wrong runqueue. | |
5032 | * 5) if it's in the wrong runqueue then the migration thread removes | |
5033 | * it and puts it into the right queue. | |
5034 | * 6) migration thread up()s the semaphore. | |
5035 | * 7) we wake up and the migration is done. | |
5036 | */ | |
5037 | ||
5038 | /* | |
5039 | * Change a given task's CPU affinity. Migrate the thread to a | |
5040 | * proper CPU and schedule it away if the CPU it's executing on | |
5041 | * is removed from the allowed bitmask. | |
5042 | * | |
5043 | * NOTE: the caller must have a valid reference to the task, the | |
41a2d6cf | 5044 | * task must not exit() & deallocate itself prematurely. The |
1da177e4 LT |
5045 | * call is not atomic; no spinlocks may be held. |
5046 | */ | |
36c8b586 | 5047 | int set_cpus_allowed(struct task_struct *p, cpumask_t new_mask) |
1da177e4 | 5048 | { |
70b97a7f | 5049 | struct migration_req req; |
1da177e4 | 5050 | unsigned long flags; |
70b97a7f | 5051 | struct rq *rq; |
48f24c4d | 5052 | int ret = 0; |
1da177e4 LT |
5053 | |
5054 | rq = task_rq_lock(p, &flags); | |
5055 | if (!cpus_intersects(new_mask, cpu_online_map)) { | |
5056 | ret = -EINVAL; | |
5057 | goto out; | |
5058 | } | |
5059 | ||
73fe6aae GH |
5060 | if (p->sched_class->set_cpus_allowed) |
5061 | p->sched_class->set_cpus_allowed(p, &new_mask); | |
5062 | else { | |
5063 | p->cpus_allowed = new_mask; | |
5064 | p->nr_cpus_allowed = cpus_weight(new_mask); | |
5065 | } | |
5066 | ||
1da177e4 LT |
5067 | /* Can the task run on the task's current CPU? If so, we're done */ |
5068 | if (cpu_isset(task_cpu(p), new_mask)) | |
5069 | goto out; | |
5070 | ||
5071 | if (migrate_task(p, any_online_cpu(new_mask), &req)) { | |
5072 | /* Need help from migration thread: drop lock and wait. */ | |
5073 | task_rq_unlock(rq, &flags); | |
5074 | wake_up_process(rq->migration_thread); | |
5075 | wait_for_completion(&req.done); | |
5076 | tlb_migrate_finish(p->mm); | |
5077 | return 0; | |
5078 | } | |
5079 | out: | |
5080 | task_rq_unlock(rq, &flags); | |
48f24c4d | 5081 | |
1da177e4 LT |
5082 | return ret; |
5083 | } | |
1da177e4 LT |
5084 | EXPORT_SYMBOL_GPL(set_cpus_allowed); |
5085 | ||
5086 | /* | |
41a2d6cf | 5087 | * Move (not current) task off this cpu, onto dest cpu. We're doing |
1da177e4 LT |
5088 | * this because either it can't run here any more (set_cpus_allowed() |
5089 | * away from this CPU, or CPU going down), or because we're | |
5090 | * attempting to rebalance this task on exec (sched_exec). | |
5091 | * | |
5092 | * So we race with normal scheduler movements, but that's OK, as long | |
5093 | * as the task is no longer on this CPU. | |
efc30814 KK |
5094 | * |
5095 | * Returns non-zero if task was successfully migrated. | |
1da177e4 | 5096 | */ |
efc30814 | 5097 | static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu) |
1da177e4 | 5098 | { |
70b97a7f | 5099 | struct rq *rq_dest, *rq_src; |
dd41f596 | 5100 | int ret = 0, on_rq; |
1da177e4 LT |
5101 | |
5102 | if (unlikely(cpu_is_offline(dest_cpu))) | |
efc30814 | 5103 | return ret; |
1da177e4 LT |
5104 | |
5105 | rq_src = cpu_rq(src_cpu); | |
5106 | rq_dest = cpu_rq(dest_cpu); | |
5107 | ||
5108 | double_rq_lock(rq_src, rq_dest); | |
5109 | /* Already moved. */ | |
5110 | if (task_cpu(p) != src_cpu) | |
5111 | goto out; | |
5112 | /* Affinity changed (again). */ | |
5113 | if (!cpu_isset(dest_cpu, p->cpus_allowed)) | |
5114 | goto out; | |
5115 | ||
dd41f596 | 5116 | on_rq = p->se.on_rq; |
6e82a3be | 5117 | if (on_rq) |
2e1cb74a | 5118 | deactivate_task(rq_src, p, 0); |
6e82a3be | 5119 | |
1da177e4 | 5120 | set_task_cpu(p, dest_cpu); |
dd41f596 IM |
5121 | if (on_rq) { |
5122 | activate_task(rq_dest, p, 0); | |
5123 | check_preempt_curr(rq_dest, p); | |
1da177e4 | 5124 | } |
efc30814 | 5125 | ret = 1; |
1da177e4 LT |
5126 | out: |
5127 | double_rq_unlock(rq_src, rq_dest); | |
efc30814 | 5128 | return ret; |
1da177e4 LT |
5129 | } |
5130 | ||
5131 | /* | |
5132 | * migration_thread - this is a highprio system thread that performs | |
5133 | * thread migration by bumping thread off CPU then 'pushing' onto | |
5134 | * another runqueue. | |
5135 | */ | |
95cdf3b7 | 5136 | static int migration_thread(void *data) |
1da177e4 | 5137 | { |
1da177e4 | 5138 | int cpu = (long)data; |
70b97a7f | 5139 | struct rq *rq; |
1da177e4 LT |
5140 | |
5141 | rq = cpu_rq(cpu); | |
5142 | BUG_ON(rq->migration_thread != current); | |
5143 | ||
5144 | set_current_state(TASK_INTERRUPTIBLE); | |
5145 | while (!kthread_should_stop()) { | |
70b97a7f | 5146 | struct migration_req *req; |
1da177e4 | 5147 | struct list_head *head; |
1da177e4 | 5148 | |
1da177e4 LT |
5149 | spin_lock_irq(&rq->lock); |
5150 | ||
5151 | if (cpu_is_offline(cpu)) { | |
5152 | spin_unlock_irq(&rq->lock); | |
5153 | goto wait_to_die; | |
5154 | } | |
5155 | ||
5156 | if (rq->active_balance) { | |
5157 | active_load_balance(rq, cpu); | |
5158 | rq->active_balance = 0; | |
5159 | } | |
5160 | ||
5161 | head = &rq->migration_queue; | |
5162 | ||
5163 | if (list_empty(head)) { | |
5164 | spin_unlock_irq(&rq->lock); | |
5165 | schedule(); | |
5166 | set_current_state(TASK_INTERRUPTIBLE); | |
5167 | continue; | |
5168 | } | |
70b97a7f | 5169 | req = list_entry(head->next, struct migration_req, list); |
1da177e4 LT |
5170 | list_del_init(head->next); |
5171 | ||
674311d5 NP |
5172 | spin_unlock(&rq->lock); |
5173 | __migrate_task(req->task, cpu, req->dest_cpu); | |
5174 | local_irq_enable(); | |
1da177e4 LT |
5175 | |
5176 | complete(&req->done); | |
5177 | } | |
5178 | __set_current_state(TASK_RUNNING); | |
5179 | return 0; | |
5180 | ||
5181 | wait_to_die: | |
5182 | /* Wait for kthread_stop */ | |
5183 | set_current_state(TASK_INTERRUPTIBLE); | |
5184 | while (!kthread_should_stop()) { | |
5185 | schedule(); | |
5186 | set_current_state(TASK_INTERRUPTIBLE); | |
5187 | } | |
5188 | __set_current_state(TASK_RUNNING); | |
5189 | return 0; | |
5190 | } | |
5191 | ||
5192 | #ifdef CONFIG_HOTPLUG_CPU | |
f7b4cddc ON |
5193 | |
5194 | static int __migrate_task_irq(struct task_struct *p, int src_cpu, int dest_cpu) | |
5195 | { | |
5196 | int ret; | |
5197 | ||
5198 | local_irq_disable(); | |
5199 | ret = __migrate_task(p, src_cpu, dest_cpu); | |
5200 | local_irq_enable(); | |
5201 | return ret; | |
5202 | } | |
5203 | ||
054b9108 | 5204 | /* |
3a4fa0a2 | 5205 | * Figure out where task on dead CPU should go, use force if necessary. |
054b9108 KK |
5206 | * NOTE: interrupts should be disabled by the caller |
5207 | */ | |
48f24c4d | 5208 | static void move_task_off_dead_cpu(int dead_cpu, struct task_struct *p) |
1da177e4 | 5209 | { |
efc30814 | 5210 | unsigned long flags; |
1da177e4 | 5211 | cpumask_t mask; |
70b97a7f IM |
5212 | struct rq *rq; |
5213 | int dest_cpu; | |
1da177e4 | 5214 | |
3a5c359a AK |
5215 | do { |
5216 | /* On same node? */ | |
5217 | mask = node_to_cpumask(cpu_to_node(dead_cpu)); | |
5218 | cpus_and(mask, mask, p->cpus_allowed); | |
5219 | dest_cpu = any_online_cpu(mask); | |
5220 | ||
5221 | /* On any allowed CPU? */ | |
5222 | if (dest_cpu == NR_CPUS) | |
5223 | dest_cpu = any_online_cpu(p->cpus_allowed); | |
5224 | ||
5225 | /* No more Mr. Nice Guy. */ | |
5226 | if (dest_cpu == NR_CPUS) { | |
470fd646 CW |
5227 | cpumask_t cpus_allowed = cpuset_cpus_allowed_locked(p); |
5228 | /* | |
5229 | * Try to stay on the same cpuset, where the | |
5230 | * current cpuset may be a subset of all cpus. | |
5231 | * The cpuset_cpus_allowed_locked() variant of | |
41a2d6cf | 5232 | * cpuset_cpus_allowed() will not block. It must be |
470fd646 CW |
5233 | * called within calls to cpuset_lock/cpuset_unlock. |
5234 | */ | |
3a5c359a | 5235 | rq = task_rq_lock(p, &flags); |
470fd646 | 5236 | p->cpus_allowed = cpus_allowed; |
3a5c359a AK |
5237 | dest_cpu = any_online_cpu(p->cpus_allowed); |
5238 | task_rq_unlock(rq, &flags); | |
1da177e4 | 5239 | |
3a5c359a AK |
5240 | /* |
5241 | * Don't tell them about moving exiting tasks or | |
5242 | * kernel threads (both mm NULL), since they never | |
5243 | * leave kernel. | |
5244 | */ | |
41a2d6cf | 5245 | if (p->mm && printk_ratelimit()) { |
3a5c359a AK |
5246 | printk(KERN_INFO "process %d (%s) no " |
5247 | "longer affine to cpu%d\n", | |
41a2d6cf IM |
5248 | task_pid_nr(p), p->comm, dead_cpu); |
5249 | } | |
3a5c359a | 5250 | } |
f7b4cddc | 5251 | } while (!__migrate_task_irq(p, dead_cpu, dest_cpu)); |
1da177e4 LT |
5252 | } |
5253 | ||
5254 | /* | |
5255 | * While a dead CPU has no uninterruptible tasks queued at this point, | |
5256 | * it might still have a nonzero ->nr_uninterruptible counter, because | |
5257 | * for performance reasons the counter is not stricly tracking tasks to | |
5258 | * their home CPUs. So we just add the counter to another CPU's counter, | |
5259 | * to keep the global sum constant after CPU-down: | |
5260 | */ | |
70b97a7f | 5261 | static void migrate_nr_uninterruptible(struct rq *rq_src) |
1da177e4 | 5262 | { |
70b97a7f | 5263 | struct rq *rq_dest = cpu_rq(any_online_cpu(CPU_MASK_ALL)); |
1da177e4 LT |
5264 | unsigned long flags; |
5265 | ||
5266 | local_irq_save(flags); | |
5267 | double_rq_lock(rq_src, rq_dest); | |
5268 | rq_dest->nr_uninterruptible += rq_src->nr_uninterruptible; | |
5269 | rq_src->nr_uninterruptible = 0; | |
5270 | double_rq_unlock(rq_src, rq_dest); | |
5271 | local_irq_restore(flags); | |
5272 | } | |
5273 | ||
5274 | /* Run through task list and migrate tasks from the dead cpu. */ | |
5275 | static void migrate_live_tasks(int src_cpu) | |
5276 | { | |
48f24c4d | 5277 | struct task_struct *p, *t; |
1da177e4 | 5278 | |
f7b4cddc | 5279 | read_lock(&tasklist_lock); |
1da177e4 | 5280 | |
48f24c4d IM |
5281 | do_each_thread(t, p) { |
5282 | if (p == current) | |
1da177e4 LT |
5283 | continue; |
5284 | ||
48f24c4d IM |
5285 | if (task_cpu(p) == src_cpu) |
5286 | move_task_off_dead_cpu(src_cpu, p); | |
5287 | } while_each_thread(t, p); | |
1da177e4 | 5288 | |
f7b4cddc | 5289 | read_unlock(&tasklist_lock); |
1da177e4 LT |
5290 | } |
5291 | ||
dd41f596 IM |
5292 | /* |
5293 | * Schedules idle task to be the next runnable task on current CPU. | |
94bc9a7b DA |
5294 | * It does so by boosting its priority to highest possible. |
5295 | * Used by CPU offline code. | |
1da177e4 LT |
5296 | */ |
5297 | void sched_idle_next(void) | |
5298 | { | |
48f24c4d | 5299 | int this_cpu = smp_processor_id(); |
70b97a7f | 5300 | struct rq *rq = cpu_rq(this_cpu); |
1da177e4 LT |
5301 | struct task_struct *p = rq->idle; |
5302 | unsigned long flags; | |
5303 | ||
5304 | /* cpu has to be offline */ | |
48f24c4d | 5305 | BUG_ON(cpu_online(this_cpu)); |
1da177e4 | 5306 | |
48f24c4d IM |
5307 | /* |
5308 | * Strictly not necessary since rest of the CPUs are stopped by now | |
5309 | * and interrupts disabled on the current cpu. | |
1da177e4 LT |
5310 | */ |
5311 | spin_lock_irqsave(&rq->lock, flags); | |
5312 | ||
dd41f596 | 5313 | __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1); |
48f24c4d | 5314 | |
94bc9a7b DA |
5315 | update_rq_clock(rq); |
5316 | activate_task(rq, p, 0); | |
1da177e4 LT |
5317 | |
5318 | spin_unlock_irqrestore(&rq->lock, flags); | |
5319 | } | |
5320 | ||
48f24c4d IM |
5321 | /* |
5322 | * Ensures that the idle task is using init_mm right before its cpu goes | |
1da177e4 LT |
5323 | * offline. |
5324 | */ | |
5325 | void idle_task_exit(void) | |
5326 | { | |
5327 | struct mm_struct *mm = current->active_mm; | |
5328 | ||
5329 | BUG_ON(cpu_online(smp_processor_id())); | |
5330 | ||
5331 | if (mm != &init_mm) | |
5332 | switch_mm(mm, &init_mm, current); | |
5333 | mmdrop(mm); | |
5334 | } | |
5335 | ||
054b9108 | 5336 | /* called under rq->lock with disabled interrupts */ |
36c8b586 | 5337 | static void migrate_dead(unsigned int dead_cpu, struct task_struct *p) |
1da177e4 | 5338 | { |
70b97a7f | 5339 | struct rq *rq = cpu_rq(dead_cpu); |
1da177e4 LT |
5340 | |
5341 | /* Must be exiting, otherwise would be on tasklist. */ | |
270f722d | 5342 | BUG_ON(!p->exit_state); |
1da177e4 LT |
5343 | |
5344 | /* Cannot have done final schedule yet: would have vanished. */ | |
c394cc9f | 5345 | BUG_ON(p->state == TASK_DEAD); |
1da177e4 | 5346 | |
48f24c4d | 5347 | get_task_struct(p); |
1da177e4 LT |
5348 | |
5349 | /* | |
5350 | * Drop lock around migration; if someone else moves it, | |
41a2d6cf | 5351 | * that's OK. No task can be added to this CPU, so iteration is |
1da177e4 LT |
5352 | * fine. |
5353 | */ | |
f7b4cddc | 5354 | spin_unlock_irq(&rq->lock); |
48f24c4d | 5355 | move_task_off_dead_cpu(dead_cpu, p); |
f7b4cddc | 5356 | spin_lock_irq(&rq->lock); |
1da177e4 | 5357 | |
48f24c4d | 5358 | put_task_struct(p); |
1da177e4 LT |
5359 | } |
5360 | ||
5361 | /* release_task() removes task from tasklist, so we won't find dead tasks. */ | |
5362 | static void migrate_dead_tasks(unsigned int dead_cpu) | |
5363 | { | |
70b97a7f | 5364 | struct rq *rq = cpu_rq(dead_cpu); |
dd41f596 | 5365 | struct task_struct *next; |
48f24c4d | 5366 | |
dd41f596 IM |
5367 | for ( ; ; ) { |
5368 | if (!rq->nr_running) | |
5369 | break; | |
a8e504d2 | 5370 | update_rq_clock(rq); |
ff95f3df | 5371 | next = pick_next_task(rq, rq->curr); |
dd41f596 IM |
5372 | if (!next) |
5373 | break; | |
5374 | migrate_dead(dead_cpu, next); | |
e692ab53 | 5375 | |
1da177e4 LT |
5376 | } |
5377 | } | |
5378 | #endif /* CONFIG_HOTPLUG_CPU */ | |
5379 | ||
e692ab53 NP |
5380 | #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL) |
5381 | ||
5382 | static struct ctl_table sd_ctl_dir[] = { | |
e0361851 AD |
5383 | { |
5384 | .procname = "sched_domain", | |
c57baf1e | 5385 | .mode = 0555, |
e0361851 | 5386 | }, |
38605cae | 5387 | {0, }, |
e692ab53 NP |
5388 | }; |
5389 | ||
5390 | static struct ctl_table sd_ctl_root[] = { | |
e0361851 | 5391 | { |
c57baf1e | 5392 | .ctl_name = CTL_KERN, |
e0361851 | 5393 | .procname = "kernel", |
c57baf1e | 5394 | .mode = 0555, |
e0361851 AD |
5395 | .child = sd_ctl_dir, |
5396 | }, | |
38605cae | 5397 | {0, }, |
e692ab53 NP |
5398 | }; |
5399 | ||
5400 | static struct ctl_table *sd_alloc_ctl_entry(int n) | |
5401 | { | |
5402 | struct ctl_table *entry = | |
5cf9f062 | 5403 | kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL); |
e692ab53 | 5404 | |
e692ab53 NP |
5405 | return entry; |
5406 | } | |
5407 | ||
6382bc90 MM |
5408 | static void sd_free_ctl_entry(struct ctl_table **tablep) |
5409 | { | |
cd790076 | 5410 | struct ctl_table *entry; |
6382bc90 | 5411 | |
cd790076 MM |
5412 | /* |
5413 | * In the intermediate directories, both the child directory and | |
5414 | * procname are dynamically allocated and could fail but the mode | |
41a2d6cf | 5415 | * will always be set. In the lowest directory the names are |
cd790076 MM |
5416 | * static strings and all have proc handlers. |
5417 | */ | |
5418 | for (entry = *tablep; entry->mode; entry++) { | |
6382bc90 MM |
5419 | if (entry->child) |
5420 | sd_free_ctl_entry(&entry->child); | |
cd790076 MM |
5421 | if (entry->proc_handler == NULL) |
5422 | kfree(entry->procname); | |
5423 | } | |
6382bc90 MM |
5424 | |
5425 | kfree(*tablep); | |
5426 | *tablep = NULL; | |
5427 | } | |
5428 | ||
e692ab53 | 5429 | static void |
e0361851 | 5430 | set_table_entry(struct ctl_table *entry, |
e692ab53 NP |
5431 | const char *procname, void *data, int maxlen, |
5432 | mode_t mode, proc_handler *proc_handler) | |
5433 | { | |
e692ab53 NP |
5434 | entry->procname = procname; |
5435 | entry->data = data; | |
5436 | entry->maxlen = maxlen; | |
5437 | entry->mode = mode; | |
5438 | entry->proc_handler = proc_handler; | |
5439 | } | |
5440 | ||
5441 | static struct ctl_table * | |
5442 | sd_alloc_ctl_domain_table(struct sched_domain *sd) | |
5443 | { | |
ace8b3d6 | 5444 | struct ctl_table *table = sd_alloc_ctl_entry(12); |
e692ab53 | 5445 | |
ad1cdc1d MM |
5446 | if (table == NULL) |
5447 | return NULL; | |
5448 | ||
e0361851 | 5449 | set_table_entry(&table[0], "min_interval", &sd->min_interval, |
e692ab53 | 5450 | sizeof(long), 0644, proc_doulongvec_minmax); |
e0361851 | 5451 | set_table_entry(&table[1], "max_interval", &sd->max_interval, |
e692ab53 | 5452 | sizeof(long), 0644, proc_doulongvec_minmax); |
e0361851 | 5453 | set_table_entry(&table[2], "busy_idx", &sd->busy_idx, |
e692ab53 | 5454 | sizeof(int), 0644, proc_dointvec_minmax); |
e0361851 | 5455 | set_table_entry(&table[3], "idle_idx", &sd->idle_idx, |
e692ab53 | 5456 | sizeof(int), 0644, proc_dointvec_minmax); |
e0361851 | 5457 | set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx, |
e692ab53 | 5458 | sizeof(int), 0644, proc_dointvec_minmax); |
e0361851 | 5459 | set_table_entry(&table[5], "wake_idx", &sd->wake_idx, |
e692ab53 | 5460 | sizeof(int), 0644, proc_dointvec_minmax); |
e0361851 | 5461 | set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx, |
e692ab53 | 5462 | sizeof(int), 0644, proc_dointvec_minmax); |
e0361851 | 5463 | set_table_entry(&table[7], "busy_factor", &sd->busy_factor, |
e692ab53 | 5464 | sizeof(int), 0644, proc_dointvec_minmax); |
e0361851 | 5465 | set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct, |
e692ab53 | 5466 | sizeof(int), 0644, proc_dointvec_minmax); |
ace8b3d6 | 5467 | set_table_entry(&table[9], "cache_nice_tries", |
e692ab53 NP |
5468 | &sd->cache_nice_tries, |
5469 | sizeof(int), 0644, proc_dointvec_minmax); | |
ace8b3d6 | 5470 | set_table_entry(&table[10], "flags", &sd->flags, |
e692ab53 | 5471 | sizeof(int), 0644, proc_dointvec_minmax); |
6323469f | 5472 | /* &table[11] is terminator */ |
e692ab53 NP |
5473 | |
5474 | return table; | |
5475 | } | |
5476 | ||
9a4e7159 | 5477 | static ctl_table *sd_alloc_ctl_cpu_table(int cpu) |
e692ab53 NP |
5478 | { |
5479 | struct ctl_table *entry, *table; | |
5480 | struct sched_domain *sd; | |
5481 | int domain_num = 0, i; | |
5482 | char buf[32]; | |
5483 | ||
5484 | for_each_domain(cpu, sd) | |
5485 | domain_num++; | |
5486 | entry = table = sd_alloc_ctl_entry(domain_num + 1); | |
ad1cdc1d MM |
5487 | if (table == NULL) |
5488 | return NULL; | |
e692ab53 NP |
5489 | |
5490 | i = 0; | |
5491 | for_each_domain(cpu, sd) { | |
5492 | snprintf(buf, 32, "domain%d", i); | |
e692ab53 | 5493 | entry->procname = kstrdup(buf, GFP_KERNEL); |
c57baf1e | 5494 | entry->mode = 0555; |
e692ab53 NP |
5495 | entry->child = sd_alloc_ctl_domain_table(sd); |
5496 | entry++; | |
5497 | i++; | |
5498 | } | |
5499 | return table; | |
5500 | } | |
5501 | ||
5502 | static struct ctl_table_header *sd_sysctl_header; | |
6382bc90 | 5503 | static void register_sched_domain_sysctl(void) |
e692ab53 NP |
5504 | { |
5505 | int i, cpu_num = num_online_cpus(); | |
5506 | struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1); | |
5507 | char buf[32]; | |
5508 | ||
7378547f MM |
5509 | WARN_ON(sd_ctl_dir[0].child); |
5510 | sd_ctl_dir[0].child = entry; | |
5511 | ||
ad1cdc1d MM |
5512 | if (entry == NULL) |
5513 | return; | |
5514 | ||
97b6ea7b | 5515 | for_each_online_cpu(i) { |
e692ab53 | 5516 | snprintf(buf, 32, "cpu%d", i); |
e692ab53 | 5517 | entry->procname = kstrdup(buf, GFP_KERNEL); |
c57baf1e | 5518 | entry->mode = 0555; |
e692ab53 | 5519 | entry->child = sd_alloc_ctl_cpu_table(i); |
97b6ea7b | 5520 | entry++; |
e692ab53 | 5521 | } |
7378547f MM |
5522 | |
5523 | WARN_ON(sd_sysctl_header); | |
e692ab53 NP |
5524 | sd_sysctl_header = register_sysctl_table(sd_ctl_root); |
5525 | } | |
6382bc90 | 5526 | |
7378547f | 5527 | /* may be called multiple times per register */ |
6382bc90 MM |
5528 | static void unregister_sched_domain_sysctl(void) |
5529 | { | |
7378547f MM |
5530 | if (sd_sysctl_header) |
5531 | unregister_sysctl_table(sd_sysctl_header); | |
6382bc90 | 5532 | sd_sysctl_header = NULL; |
7378547f MM |
5533 | if (sd_ctl_dir[0].child) |
5534 | sd_free_ctl_entry(&sd_ctl_dir[0].child); | |
6382bc90 | 5535 | } |
e692ab53 | 5536 | #else |
6382bc90 MM |
5537 | static void register_sched_domain_sysctl(void) |
5538 | { | |
5539 | } | |
5540 | static void unregister_sched_domain_sysctl(void) | |
e692ab53 NP |
5541 | { |
5542 | } | |
5543 | #endif | |
5544 | ||
1da177e4 LT |
5545 | /* |
5546 | * migration_call - callback that gets triggered when a CPU is added. | |
5547 | * Here we can start up the necessary migration thread for the new CPU. | |
5548 | */ | |
48f24c4d IM |
5549 | static int __cpuinit |
5550 | migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) | |
1da177e4 | 5551 | { |
1da177e4 | 5552 | struct task_struct *p; |
48f24c4d | 5553 | int cpu = (long)hcpu; |
1da177e4 | 5554 | unsigned long flags; |
70b97a7f | 5555 | struct rq *rq; |
1da177e4 LT |
5556 | |
5557 | switch (action) { | |
5be9361c | 5558 | |
1da177e4 | 5559 | case CPU_UP_PREPARE: |
8bb78442 | 5560 | case CPU_UP_PREPARE_FROZEN: |
dd41f596 | 5561 | p = kthread_create(migration_thread, hcpu, "migration/%d", cpu); |
1da177e4 LT |
5562 | if (IS_ERR(p)) |
5563 | return NOTIFY_BAD; | |
1da177e4 LT |
5564 | kthread_bind(p, cpu); |
5565 | /* Must be high prio: stop_machine expects to yield to it. */ | |
5566 | rq = task_rq_lock(p, &flags); | |
dd41f596 | 5567 | __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1); |
1da177e4 LT |
5568 | task_rq_unlock(rq, &flags); |
5569 | cpu_rq(cpu)->migration_thread = p; | |
5570 | break; | |
48f24c4d | 5571 | |
1da177e4 | 5572 | case CPU_ONLINE: |
8bb78442 | 5573 | case CPU_ONLINE_FROZEN: |
3a4fa0a2 | 5574 | /* Strictly unnecessary, as first user will wake it. */ |
1da177e4 | 5575 | wake_up_process(cpu_rq(cpu)->migration_thread); |
57d885fe GH |
5576 | |
5577 | /* Update our root-domain */ | |
5578 | rq = cpu_rq(cpu); | |
5579 | spin_lock_irqsave(&rq->lock, flags); | |
5580 | if (rq->rd) { | |
5581 | BUG_ON(!cpu_isset(cpu, rq->rd->span)); | |
5582 | cpu_set(cpu, rq->rd->online); | |
5583 | } | |
5584 | spin_unlock_irqrestore(&rq->lock, flags); | |
1da177e4 | 5585 | break; |
48f24c4d | 5586 | |
1da177e4 LT |
5587 | #ifdef CONFIG_HOTPLUG_CPU |
5588 | case CPU_UP_CANCELED: | |
8bb78442 | 5589 | case CPU_UP_CANCELED_FROZEN: |
fc75cdfa HC |
5590 | if (!cpu_rq(cpu)->migration_thread) |
5591 | break; | |
41a2d6cf | 5592 | /* Unbind it from offline cpu so it can run. Fall thru. */ |
a4c4af7c HC |
5593 | kthread_bind(cpu_rq(cpu)->migration_thread, |
5594 | any_online_cpu(cpu_online_map)); | |
1da177e4 LT |
5595 | kthread_stop(cpu_rq(cpu)->migration_thread); |
5596 | cpu_rq(cpu)->migration_thread = NULL; | |
5597 | break; | |
48f24c4d | 5598 | |
1da177e4 | 5599 | case CPU_DEAD: |
8bb78442 | 5600 | case CPU_DEAD_FROZEN: |
470fd646 | 5601 | cpuset_lock(); /* around calls to cpuset_cpus_allowed_lock() */ |
1da177e4 LT |
5602 | migrate_live_tasks(cpu); |
5603 | rq = cpu_rq(cpu); | |
5604 | kthread_stop(rq->migration_thread); | |
5605 | rq->migration_thread = NULL; | |
5606 | /* Idle task back to normal (off runqueue, low prio) */ | |
d2da272a | 5607 | spin_lock_irq(&rq->lock); |
a8e504d2 | 5608 | update_rq_clock(rq); |
2e1cb74a | 5609 | deactivate_task(rq, rq->idle, 0); |
1da177e4 | 5610 | rq->idle->static_prio = MAX_PRIO; |
dd41f596 IM |
5611 | __setscheduler(rq, rq->idle, SCHED_NORMAL, 0); |
5612 | rq->idle->sched_class = &idle_sched_class; | |
1da177e4 | 5613 | migrate_dead_tasks(cpu); |
d2da272a | 5614 | spin_unlock_irq(&rq->lock); |
470fd646 | 5615 | cpuset_unlock(); |
1da177e4 LT |
5616 | migrate_nr_uninterruptible(rq); |
5617 | BUG_ON(rq->nr_running != 0); | |
5618 | ||
41a2d6cf IM |
5619 | /* |
5620 | * No need to migrate the tasks: it was best-effort if | |
5621 | * they didn't take sched_hotcpu_mutex. Just wake up | |
5622 | * the requestors. | |
5623 | */ | |
1da177e4 LT |
5624 | spin_lock_irq(&rq->lock); |
5625 | while (!list_empty(&rq->migration_queue)) { | |
70b97a7f IM |
5626 | struct migration_req *req; |
5627 | ||
1da177e4 | 5628 | req = list_entry(rq->migration_queue.next, |
70b97a7f | 5629 | struct migration_req, list); |
1da177e4 LT |
5630 | list_del_init(&req->list); |
5631 | complete(&req->done); | |
5632 | } | |
5633 | spin_unlock_irq(&rq->lock); | |
5634 | break; | |
57d885fe GH |
5635 | |
5636 | case CPU_DOWN_PREPARE: | |
5637 | /* Update our root-domain */ | |
5638 | rq = cpu_rq(cpu); | |
5639 | spin_lock_irqsave(&rq->lock, flags); | |
5640 | if (rq->rd) { | |
5641 | BUG_ON(!cpu_isset(cpu, rq->rd->span)); | |
5642 | cpu_clear(cpu, rq->rd->online); | |
5643 | } | |
5644 | spin_unlock_irqrestore(&rq->lock, flags); | |
5645 | break; | |
1da177e4 LT |
5646 | #endif |
5647 | } | |
5648 | return NOTIFY_OK; | |
5649 | } | |
5650 | ||
5651 | /* Register at highest priority so that task migration (migrate_all_tasks) | |
5652 | * happens before everything else. | |
5653 | */ | |
26c2143b | 5654 | static struct notifier_block __cpuinitdata migration_notifier = { |
1da177e4 LT |
5655 | .notifier_call = migration_call, |
5656 | .priority = 10 | |
5657 | }; | |
5658 | ||
e6fe6649 | 5659 | void __init migration_init(void) |
1da177e4 LT |
5660 | { |
5661 | void *cpu = (void *)(long)smp_processor_id(); | |
07dccf33 | 5662 | int err; |
48f24c4d IM |
5663 | |
5664 | /* Start one for the boot CPU: */ | |
07dccf33 AM |
5665 | err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu); |
5666 | BUG_ON(err == NOTIFY_BAD); | |
1da177e4 LT |
5667 | migration_call(&migration_notifier, CPU_ONLINE, cpu); |
5668 | register_cpu_notifier(&migration_notifier); | |
1da177e4 LT |
5669 | } |
5670 | #endif | |
5671 | ||
5672 | #ifdef CONFIG_SMP | |
476f3534 CL |
5673 | |
5674 | /* Number of possible processor ids */ | |
5675 | int nr_cpu_ids __read_mostly = NR_CPUS; | |
5676 | EXPORT_SYMBOL(nr_cpu_ids); | |
5677 | ||
3e9830dc | 5678 | #ifdef CONFIG_SCHED_DEBUG |
4dcf6aff IM |
5679 | |
5680 | static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level) | |
1da177e4 | 5681 | { |
4dcf6aff IM |
5682 | struct sched_group *group = sd->groups; |
5683 | cpumask_t groupmask; | |
5684 | char str[NR_CPUS]; | |
1da177e4 | 5685 | |
4dcf6aff IM |
5686 | cpumask_scnprintf(str, NR_CPUS, sd->span); |
5687 | cpus_clear(groupmask); | |
5688 | ||
5689 | printk(KERN_DEBUG "%*s domain %d: ", level, "", level); | |
5690 | ||
5691 | if (!(sd->flags & SD_LOAD_BALANCE)) { | |
5692 | printk("does not load-balance\n"); | |
5693 | if (sd->parent) | |
5694 | printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain" | |
5695 | " has parent"); | |
5696 | return -1; | |
41c7ce9a NP |
5697 | } |
5698 | ||
4dcf6aff IM |
5699 | printk(KERN_CONT "span %s\n", str); |
5700 | ||
5701 | if (!cpu_isset(cpu, sd->span)) { | |
5702 | printk(KERN_ERR "ERROR: domain->span does not contain " | |
5703 | "CPU%d\n", cpu); | |
5704 | } | |
5705 | if (!cpu_isset(cpu, group->cpumask)) { | |
5706 | printk(KERN_ERR "ERROR: domain->groups does not contain" | |
5707 | " CPU%d\n", cpu); | |
5708 | } | |
1da177e4 | 5709 | |
4dcf6aff | 5710 | printk(KERN_DEBUG "%*s groups:", level + 1, ""); |
1da177e4 | 5711 | do { |
4dcf6aff IM |
5712 | if (!group) { |
5713 | printk("\n"); | |
5714 | printk(KERN_ERR "ERROR: group is NULL\n"); | |
1da177e4 LT |
5715 | break; |
5716 | } | |
5717 | ||
4dcf6aff IM |
5718 | if (!group->__cpu_power) { |
5719 | printk(KERN_CONT "\n"); | |
5720 | printk(KERN_ERR "ERROR: domain->cpu_power not " | |
5721 | "set\n"); | |
5722 | break; | |
5723 | } | |
1da177e4 | 5724 | |
4dcf6aff IM |
5725 | if (!cpus_weight(group->cpumask)) { |
5726 | printk(KERN_CONT "\n"); | |
5727 | printk(KERN_ERR "ERROR: empty group\n"); | |
5728 | break; | |
5729 | } | |
1da177e4 | 5730 | |
4dcf6aff IM |
5731 | if (cpus_intersects(groupmask, group->cpumask)) { |
5732 | printk(KERN_CONT "\n"); | |
5733 | printk(KERN_ERR "ERROR: repeated CPUs\n"); | |
5734 | break; | |
5735 | } | |
1da177e4 | 5736 | |
4dcf6aff | 5737 | cpus_or(groupmask, groupmask, group->cpumask); |
1da177e4 | 5738 | |
4dcf6aff IM |
5739 | cpumask_scnprintf(str, NR_CPUS, group->cpumask); |
5740 | printk(KERN_CONT " %s", str); | |
1da177e4 | 5741 | |
4dcf6aff IM |
5742 | group = group->next; |
5743 | } while (group != sd->groups); | |
5744 | printk(KERN_CONT "\n"); | |
1da177e4 | 5745 | |
4dcf6aff IM |
5746 | if (!cpus_equal(sd->span, groupmask)) |
5747 | printk(KERN_ERR "ERROR: groups don't span domain->span\n"); | |
1da177e4 | 5748 | |
4dcf6aff IM |
5749 | if (sd->parent && !cpus_subset(groupmask, sd->parent->span)) |
5750 | printk(KERN_ERR "ERROR: parent span is not a superset " | |
5751 | "of domain->span\n"); | |
5752 | return 0; | |
5753 | } | |
1da177e4 | 5754 | |
4dcf6aff IM |
5755 | static void sched_domain_debug(struct sched_domain *sd, int cpu) |
5756 | { | |
5757 | int level = 0; | |
1da177e4 | 5758 | |
4dcf6aff IM |
5759 | if (!sd) { |
5760 | printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu); | |
5761 | return; | |
5762 | } | |
1da177e4 | 5763 | |
4dcf6aff IM |
5764 | printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu); |
5765 | ||
5766 | for (;;) { | |
5767 | if (sched_domain_debug_one(sd, cpu, level)) | |
5768 | break; | |
1da177e4 LT |
5769 | level++; |
5770 | sd = sd->parent; | |
33859f7f | 5771 | if (!sd) |
4dcf6aff IM |
5772 | break; |
5773 | } | |
1da177e4 LT |
5774 | } |
5775 | #else | |
48f24c4d | 5776 | # define sched_domain_debug(sd, cpu) do { } while (0) |
1da177e4 LT |
5777 | #endif |
5778 | ||
1a20ff27 | 5779 | static int sd_degenerate(struct sched_domain *sd) |
245af2c7 SS |
5780 | { |
5781 | if (cpus_weight(sd->span) == 1) | |
5782 | return 1; | |
5783 | ||
5784 | /* Following flags need at least 2 groups */ | |
5785 | if (sd->flags & (SD_LOAD_BALANCE | | |
5786 | SD_BALANCE_NEWIDLE | | |
5787 | SD_BALANCE_FORK | | |
89c4710e SS |
5788 | SD_BALANCE_EXEC | |
5789 | SD_SHARE_CPUPOWER | | |
5790 | SD_SHARE_PKG_RESOURCES)) { | |
245af2c7 SS |
5791 | if (sd->groups != sd->groups->next) |
5792 | return 0; | |
5793 | } | |
5794 | ||
5795 | /* Following flags don't use groups */ | |
5796 | if (sd->flags & (SD_WAKE_IDLE | | |
5797 | SD_WAKE_AFFINE | | |
5798 | SD_WAKE_BALANCE)) | |
5799 | return 0; | |
5800 | ||
5801 | return 1; | |
5802 | } | |
5803 | ||
48f24c4d IM |
5804 | static int |
5805 | sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent) | |
245af2c7 SS |
5806 | { |
5807 | unsigned long cflags = sd->flags, pflags = parent->flags; | |
5808 | ||
5809 | if (sd_degenerate(parent)) | |
5810 | return 1; | |
5811 | ||
5812 | if (!cpus_equal(sd->span, parent->span)) | |
5813 | return 0; | |
5814 | ||
5815 | /* Does parent contain flags not in child? */ | |
5816 | /* WAKE_BALANCE is a subset of WAKE_AFFINE */ | |
5817 | if (cflags & SD_WAKE_AFFINE) | |
5818 | pflags &= ~SD_WAKE_BALANCE; | |
5819 | /* Flags needing groups don't count if only 1 group in parent */ | |
5820 | if (parent->groups == parent->groups->next) { | |
5821 | pflags &= ~(SD_LOAD_BALANCE | | |
5822 | SD_BALANCE_NEWIDLE | | |
5823 | SD_BALANCE_FORK | | |
89c4710e SS |
5824 | SD_BALANCE_EXEC | |
5825 | SD_SHARE_CPUPOWER | | |
5826 | SD_SHARE_PKG_RESOURCES); | |
245af2c7 SS |
5827 | } |
5828 | if (~cflags & pflags) | |
5829 | return 0; | |
5830 | ||
5831 | return 1; | |
5832 | } | |
5833 | ||
57d885fe GH |
5834 | static void rq_attach_root(struct rq *rq, struct root_domain *rd) |
5835 | { | |
5836 | unsigned long flags; | |
5837 | const struct sched_class *class; | |
5838 | ||
5839 | spin_lock_irqsave(&rq->lock, flags); | |
5840 | ||
5841 | if (rq->rd) { | |
5842 | struct root_domain *old_rd = rq->rd; | |
5843 | ||
5844 | for (class = sched_class_highest; class; class = class->next) | |
5845 | if (class->leave_domain) | |
5846 | class->leave_domain(rq); | |
5847 | ||
5848 | if (atomic_dec_and_test(&old_rd->refcount)) | |
5849 | kfree(old_rd); | |
5850 | } | |
5851 | ||
5852 | atomic_inc(&rd->refcount); | |
5853 | rq->rd = rd; | |
5854 | ||
5855 | for (class = sched_class_highest; class; class = class->next) | |
5856 | if (class->join_domain) | |
5857 | class->join_domain(rq); | |
5858 | ||
5859 | spin_unlock_irqrestore(&rq->lock, flags); | |
5860 | } | |
5861 | ||
5862 | static void init_rootdomain(struct root_domain *rd, const cpumask_t *map) | |
5863 | { | |
5864 | memset(rd, 0, sizeof(*rd)); | |
5865 | ||
5866 | rd->span = *map; | |
5867 | cpus_and(rd->online, rd->span, cpu_online_map); | |
5868 | } | |
5869 | ||
5870 | static void init_defrootdomain(void) | |
5871 | { | |
5872 | cpumask_t cpus = CPU_MASK_ALL; | |
5873 | ||
5874 | init_rootdomain(&def_root_domain, &cpus); | |
5875 | atomic_set(&def_root_domain.refcount, 1); | |
5876 | } | |
5877 | ||
5878 | static struct root_domain *alloc_rootdomain(const cpumask_t *map) | |
5879 | { | |
5880 | struct root_domain *rd; | |
5881 | ||
5882 | rd = kmalloc(sizeof(*rd), GFP_KERNEL); | |
5883 | if (!rd) | |
5884 | return NULL; | |
5885 | ||
5886 | init_rootdomain(rd, map); | |
5887 | ||
5888 | return rd; | |
5889 | } | |
5890 | ||
1da177e4 LT |
5891 | /* |
5892 | * Attach the domain 'sd' to 'cpu' as its base domain. Callers must | |
5893 | * hold the hotplug lock. | |
5894 | */ | |
57d885fe GH |
5895 | static void cpu_attach_domain(struct sched_domain *sd, |
5896 | struct root_domain *rd, int cpu) | |
1da177e4 | 5897 | { |
70b97a7f | 5898 | struct rq *rq = cpu_rq(cpu); |
245af2c7 SS |
5899 | struct sched_domain *tmp; |
5900 | ||
5901 | /* Remove the sched domains which do not contribute to scheduling. */ | |
5902 | for (tmp = sd; tmp; tmp = tmp->parent) { | |
5903 | struct sched_domain *parent = tmp->parent; | |
5904 | if (!parent) | |
5905 | break; | |
1a848870 | 5906 | if (sd_parent_degenerate(tmp, parent)) { |
245af2c7 | 5907 | tmp->parent = parent->parent; |
1a848870 SS |
5908 | if (parent->parent) |
5909 | parent->parent->child = tmp; | |
5910 | } | |
245af2c7 SS |
5911 | } |
5912 | ||
1a848870 | 5913 | if (sd && sd_degenerate(sd)) { |
245af2c7 | 5914 | sd = sd->parent; |
1a848870 SS |
5915 | if (sd) |
5916 | sd->child = NULL; | |
5917 | } | |
1da177e4 LT |
5918 | |
5919 | sched_domain_debug(sd, cpu); | |
5920 | ||
57d885fe | 5921 | rq_attach_root(rq, rd); |
674311d5 | 5922 | rcu_assign_pointer(rq->sd, sd); |
1da177e4 LT |
5923 | } |
5924 | ||
5925 | /* cpus with isolated domains */ | |
67af63a6 | 5926 | static cpumask_t cpu_isolated_map = CPU_MASK_NONE; |
1da177e4 LT |
5927 | |
5928 | /* Setup the mask of cpus configured for isolated domains */ | |
5929 | static int __init isolated_cpu_setup(char *str) | |
5930 | { | |
5931 | int ints[NR_CPUS], i; | |
5932 | ||
5933 | str = get_options(str, ARRAY_SIZE(ints), ints); | |
5934 | cpus_clear(cpu_isolated_map); | |
5935 | for (i = 1; i <= ints[0]; i++) | |
5936 | if (ints[i] < NR_CPUS) | |
5937 | cpu_set(ints[i], cpu_isolated_map); | |
5938 | return 1; | |
5939 | } | |
5940 | ||
8927f494 | 5941 | __setup("isolcpus=", isolated_cpu_setup); |
1da177e4 LT |
5942 | |
5943 | /* | |
6711cab4 SS |
5944 | * init_sched_build_groups takes the cpumask we wish to span, and a pointer |
5945 | * to a function which identifies what group(along with sched group) a CPU | |
5946 | * belongs to. The return value of group_fn must be a >= 0 and < NR_CPUS | |
5947 | * (due to the fact that we keep track of groups covered with a cpumask_t). | |
1da177e4 LT |
5948 | * |
5949 | * init_sched_build_groups will build a circular linked list of the groups | |
5950 | * covered by the given span, and will set each group's ->cpumask correctly, | |
5951 | * and ->cpu_power to 0. | |
5952 | */ | |
a616058b | 5953 | static void |
6711cab4 SS |
5954 | init_sched_build_groups(cpumask_t span, const cpumask_t *cpu_map, |
5955 | int (*group_fn)(int cpu, const cpumask_t *cpu_map, | |
5956 | struct sched_group **sg)) | |
1da177e4 LT |
5957 | { |
5958 | struct sched_group *first = NULL, *last = NULL; | |
5959 | cpumask_t covered = CPU_MASK_NONE; | |
5960 | int i; | |
5961 | ||
5962 | for_each_cpu_mask(i, span) { | |
6711cab4 SS |
5963 | struct sched_group *sg; |
5964 | int group = group_fn(i, cpu_map, &sg); | |
1da177e4 LT |
5965 | int j; |
5966 | ||
5967 | if (cpu_isset(i, covered)) | |
5968 | continue; | |
5969 | ||
5970 | sg->cpumask = CPU_MASK_NONE; | |
5517d86b | 5971 | sg->__cpu_power = 0; |
1da177e4 LT |
5972 | |
5973 | for_each_cpu_mask(j, span) { | |
6711cab4 | 5974 | if (group_fn(j, cpu_map, NULL) != group) |
1da177e4 LT |
5975 | continue; |
5976 | ||
5977 | cpu_set(j, covered); | |
5978 | cpu_set(j, sg->cpumask); | |
5979 | } | |
5980 | if (!first) | |
5981 | first = sg; | |
5982 | if (last) | |
5983 | last->next = sg; | |
5984 | last = sg; | |
5985 | } | |
5986 | last->next = first; | |
5987 | } | |
5988 | ||
9c1cfda2 | 5989 | #define SD_NODES_PER_DOMAIN 16 |
1da177e4 | 5990 | |
9c1cfda2 | 5991 | #ifdef CONFIG_NUMA |
198e2f18 | 5992 | |
9c1cfda2 JH |
5993 | /** |
5994 | * find_next_best_node - find the next node to include in a sched_domain | |
5995 | * @node: node whose sched_domain we're building | |
5996 | * @used_nodes: nodes already in the sched_domain | |
5997 | * | |
41a2d6cf | 5998 | * Find the next node to include in a given scheduling domain. Simply |
9c1cfda2 JH |
5999 | * finds the closest node not already in the @used_nodes map. |
6000 | * | |
6001 | * Should use nodemask_t. | |
6002 | */ | |
6003 | static int find_next_best_node(int node, unsigned long *used_nodes) | |
6004 | { | |
6005 | int i, n, val, min_val, best_node = 0; | |
6006 | ||
6007 | min_val = INT_MAX; | |
6008 | ||
6009 | for (i = 0; i < MAX_NUMNODES; i++) { | |
6010 | /* Start at @node */ | |
6011 | n = (node + i) % MAX_NUMNODES; | |
6012 | ||
6013 | if (!nr_cpus_node(n)) | |
6014 | continue; | |
6015 | ||
6016 | /* Skip already used nodes */ | |
6017 | if (test_bit(n, used_nodes)) | |
6018 | continue; | |
6019 | ||
6020 | /* Simple min distance search */ | |
6021 | val = node_distance(node, n); | |
6022 | ||
6023 | if (val < min_val) { | |
6024 | min_val = val; | |
6025 | best_node = n; | |
6026 | } | |
6027 | } | |
6028 | ||
6029 | set_bit(best_node, used_nodes); | |
6030 | return best_node; | |
6031 | } | |
6032 | ||
6033 | /** | |
6034 | * sched_domain_node_span - get a cpumask for a node's sched_domain | |
6035 | * @node: node whose cpumask we're constructing | |
6036 | * @size: number of nodes to include in this span | |
6037 | * | |
41a2d6cf | 6038 | * Given a node, construct a good cpumask for its sched_domain to span. It |
9c1cfda2 JH |
6039 | * should be one that prevents unnecessary balancing, but also spreads tasks |
6040 | * out optimally. | |
6041 | */ | |
6042 | static cpumask_t sched_domain_node_span(int node) | |
6043 | { | |
9c1cfda2 | 6044 | DECLARE_BITMAP(used_nodes, MAX_NUMNODES); |
48f24c4d IM |
6045 | cpumask_t span, nodemask; |
6046 | int i; | |
9c1cfda2 JH |
6047 | |
6048 | cpus_clear(span); | |
6049 | bitmap_zero(used_nodes, MAX_NUMNODES); | |
6050 | ||
6051 | nodemask = node_to_cpumask(node); | |
6052 | cpus_or(span, span, nodemask); | |
6053 | set_bit(node, used_nodes); | |
6054 | ||
6055 | for (i = 1; i < SD_NODES_PER_DOMAIN; i++) { | |
6056 | int next_node = find_next_best_node(node, used_nodes); | |
48f24c4d | 6057 | |
9c1cfda2 JH |
6058 | nodemask = node_to_cpumask(next_node); |
6059 | cpus_or(span, span, nodemask); | |
6060 | } | |
6061 | ||
6062 | return span; | |
6063 | } | |
6064 | #endif | |
6065 | ||
5c45bf27 | 6066 | int sched_smt_power_savings = 0, sched_mc_power_savings = 0; |
48f24c4d | 6067 | |
9c1cfda2 | 6068 | /* |
48f24c4d | 6069 | * SMT sched-domains: |
9c1cfda2 | 6070 | */ |
1da177e4 LT |
6071 | #ifdef CONFIG_SCHED_SMT |
6072 | static DEFINE_PER_CPU(struct sched_domain, cpu_domains); | |
6711cab4 | 6073 | static DEFINE_PER_CPU(struct sched_group, sched_group_cpus); |
48f24c4d | 6074 | |
41a2d6cf IM |
6075 | static int |
6076 | cpu_to_cpu_group(int cpu, const cpumask_t *cpu_map, struct sched_group **sg) | |
1da177e4 | 6077 | { |
6711cab4 SS |
6078 | if (sg) |
6079 | *sg = &per_cpu(sched_group_cpus, cpu); | |
1da177e4 LT |
6080 | return cpu; |
6081 | } | |
6082 | #endif | |
6083 | ||
48f24c4d IM |
6084 | /* |
6085 | * multi-core sched-domains: | |
6086 | */ | |
1e9f28fa SS |
6087 | #ifdef CONFIG_SCHED_MC |
6088 | static DEFINE_PER_CPU(struct sched_domain, core_domains); | |
6711cab4 | 6089 | static DEFINE_PER_CPU(struct sched_group, sched_group_core); |
1e9f28fa SS |
6090 | #endif |
6091 | ||
6092 | #if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT) | |
41a2d6cf IM |
6093 | static int |
6094 | cpu_to_core_group(int cpu, const cpumask_t *cpu_map, struct sched_group **sg) | |
1e9f28fa | 6095 | { |
6711cab4 | 6096 | int group; |
d5a7430d | 6097 | cpumask_t mask = per_cpu(cpu_sibling_map, cpu); |
a616058b | 6098 | cpus_and(mask, mask, *cpu_map); |
6711cab4 SS |
6099 | group = first_cpu(mask); |
6100 | if (sg) | |
6101 | *sg = &per_cpu(sched_group_core, group); | |
6102 | return group; | |
1e9f28fa SS |
6103 | } |
6104 | #elif defined(CONFIG_SCHED_MC) | |
41a2d6cf IM |
6105 | static int |
6106 | cpu_to_core_group(int cpu, const cpumask_t *cpu_map, struct sched_group **sg) | |
1e9f28fa | 6107 | { |
6711cab4 SS |
6108 | if (sg) |
6109 | *sg = &per_cpu(sched_group_core, cpu); | |
1e9f28fa SS |
6110 | return cpu; |
6111 | } | |
6112 | #endif | |
6113 | ||
1da177e4 | 6114 | static DEFINE_PER_CPU(struct sched_domain, phys_domains); |
6711cab4 | 6115 | static DEFINE_PER_CPU(struct sched_group, sched_group_phys); |
48f24c4d | 6116 | |
41a2d6cf IM |
6117 | static int |
6118 | cpu_to_phys_group(int cpu, const cpumask_t *cpu_map, struct sched_group **sg) | |
1da177e4 | 6119 | { |
6711cab4 | 6120 | int group; |
48f24c4d | 6121 | #ifdef CONFIG_SCHED_MC |
1e9f28fa | 6122 | cpumask_t mask = cpu_coregroup_map(cpu); |
a616058b | 6123 | cpus_and(mask, mask, *cpu_map); |
6711cab4 | 6124 | group = first_cpu(mask); |
1e9f28fa | 6125 | #elif defined(CONFIG_SCHED_SMT) |
d5a7430d | 6126 | cpumask_t mask = per_cpu(cpu_sibling_map, cpu); |
a616058b | 6127 | cpus_and(mask, mask, *cpu_map); |
6711cab4 | 6128 | group = first_cpu(mask); |
1da177e4 | 6129 | #else |
6711cab4 | 6130 | group = cpu; |
1da177e4 | 6131 | #endif |
6711cab4 SS |
6132 | if (sg) |
6133 | *sg = &per_cpu(sched_group_phys, group); | |
6134 | return group; | |
1da177e4 LT |
6135 | } |
6136 | ||
6137 | #ifdef CONFIG_NUMA | |
1da177e4 | 6138 | /* |
9c1cfda2 JH |
6139 | * The init_sched_build_groups can't handle what we want to do with node |
6140 | * groups, so roll our own. Now each node has its own list of groups which | |
6141 | * gets dynamically allocated. | |
1da177e4 | 6142 | */ |
9c1cfda2 | 6143 | static DEFINE_PER_CPU(struct sched_domain, node_domains); |
d1b55138 | 6144 | static struct sched_group **sched_group_nodes_bycpu[NR_CPUS]; |
1da177e4 | 6145 | |
9c1cfda2 | 6146 | static DEFINE_PER_CPU(struct sched_domain, allnodes_domains); |
6711cab4 | 6147 | static DEFINE_PER_CPU(struct sched_group, sched_group_allnodes); |
9c1cfda2 | 6148 | |
6711cab4 SS |
6149 | static int cpu_to_allnodes_group(int cpu, const cpumask_t *cpu_map, |
6150 | struct sched_group **sg) | |
9c1cfda2 | 6151 | { |
6711cab4 SS |
6152 | cpumask_t nodemask = node_to_cpumask(cpu_to_node(cpu)); |
6153 | int group; | |
6154 | ||
6155 | cpus_and(nodemask, nodemask, *cpu_map); | |
6156 | group = first_cpu(nodemask); | |
6157 | ||
6158 | if (sg) | |
6159 | *sg = &per_cpu(sched_group_allnodes, group); | |
6160 | return group; | |
1da177e4 | 6161 | } |
6711cab4 | 6162 | |
08069033 SS |
6163 | static void init_numa_sched_groups_power(struct sched_group *group_head) |
6164 | { | |
6165 | struct sched_group *sg = group_head; | |
6166 | int j; | |
6167 | ||
6168 | if (!sg) | |
6169 | return; | |
3a5c359a AK |
6170 | do { |
6171 | for_each_cpu_mask(j, sg->cpumask) { | |
6172 | struct sched_domain *sd; | |
08069033 | 6173 | |
3a5c359a AK |
6174 | sd = &per_cpu(phys_domains, j); |
6175 | if (j != first_cpu(sd->groups->cpumask)) { | |
6176 | /* | |
6177 | * Only add "power" once for each | |
6178 | * physical package. | |
6179 | */ | |
6180 | continue; | |
6181 | } | |
08069033 | 6182 | |
3a5c359a AK |
6183 | sg_inc_cpu_power(sg, sd->groups->__cpu_power); |
6184 | } | |
6185 | sg = sg->next; | |
6186 | } while (sg != group_head); | |
08069033 | 6187 | } |
1da177e4 LT |
6188 | #endif |
6189 | ||
a616058b | 6190 | #ifdef CONFIG_NUMA |
51888ca2 SV |
6191 | /* Free memory allocated for various sched_group structures */ |
6192 | static void free_sched_groups(const cpumask_t *cpu_map) | |
6193 | { | |
a616058b | 6194 | int cpu, i; |
51888ca2 SV |
6195 | |
6196 | for_each_cpu_mask(cpu, *cpu_map) { | |
51888ca2 SV |
6197 | struct sched_group **sched_group_nodes |
6198 | = sched_group_nodes_bycpu[cpu]; | |
6199 | ||
51888ca2 SV |
6200 | if (!sched_group_nodes) |
6201 | continue; | |
6202 | ||
6203 | for (i = 0; i < MAX_NUMNODES; i++) { | |
6204 | cpumask_t nodemask = node_to_cpumask(i); | |
6205 | struct sched_group *oldsg, *sg = sched_group_nodes[i]; | |
6206 | ||
6207 | cpus_and(nodemask, nodemask, *cpu_map); | |
6208 | if (cpus_empty(nodemask)) | |
6209 | continue; | |
6210 | ||
6211 | if (sg == NULL) | |
6212 | continue; | |
6213 | sg = sg->next; | |
6214 | next_sg: | |
6215 | oldsg = sg; | |
6216 | sg = sg->next; | |
6217 | kfree(oldsg); | |
6218 | if (oldsg != sched_group_nodes[i]) | |
6219 | goto next_sg; | |
6220 | } | |
6221 | kfree(sched_group_nodes); | |
6222 | sched_group_nodes_bycpu[cpu] = NULL; | |
6223 | } | |
51888ca2 | 6224 | } |
a616058b SS |
6225 | #else |
6226 | static void free_sched_groups(const cpumask_t *cpu_map) | |
6227 | { | |
6228 | } | |
6229 | #endif | |
51888ca2 | 6230 | |
89c4710e SS |
6231 | /* |
6232 | * Initialize sched groups cpu_power. | |
6233 | * | |
6234 | * cpu_power indicates the capacity of sched group, which is used while | |
6235 | * distributing the load between different sched groups in a sched domain. | |
6236 | * Typically cpu_power for all the groups in a sched domain will be same unless | |
6237 | * there are asymmetries in the topology. If there are asymmetries, group | |
6238 | * having more cpu_power will pickup more load compared to the group having | |
6239 | * less cpu_power. | |
6240 | * | |
6241 | * cpu_power will be a multiple of SCHED_LOAD_SCALE. This multiple represents | |
6242 | * the maximum number of tasks a group can handle in the presence of other idle | |
6243 | * or lightly loaded groups in the same sched domain. | |
6244 | */ | |
6245 | static void init_sched_groups_power(int cpu, struct sched_domain *sd) | |
6246 | { | |
6247 | struct sched_domain *child; | |
6248 | struct sched_group *group; | |
6249 | ||
6250 | WARN_ON(!sd || !sd->groups); | |
6251 | ||
6252 | if (cpu != first_cpu(sd->groups->cpumask)) | |
6253 | return; | |
6254 | ||
6255 | child = sd->child; | |
6256 | ||
5517d86b ED |
6257 | sd->groups->__cpu_power = 0; |
6258 | ||
89c4710e SS |
6259 | /* |
6260 | * For perf policy, if the groups in child domain share resources | |
6261 | * (for example cores sharing some portions of the cache hierarchy | |
6262 | * or SMT), then set this domain groups cpu_power such that each group | |
6263 | * can handle only one task, when there are other idle groups in the | |
6264 | * same sched domain. | |
6265 | */ | |
6266 | if (!child || (!(sd->flags & SD_POWERSAVINGS_BALANCE) && | |
6267 | (child->flags & | |
6268 | (SD_SHARE_CPUPOWER | SD_SHARE_PKG_RESOURCES)))) { | |
5517d86b | 6269 | sg_inc_cpu_power(sd->groups, SCHED_LOAD_SCALE); |
89c4710e SS |
6270 | return; |
6271 | } | |
6272 | ||
89c4710e SS |
6273 | /* |
6274 | * add cpu_power of each child group to this groups cpu_power | |
6275 | */ | |
6276 | group = child->groups; | |
6277 | do { | |
5517d86b | 6278 | sg_inc_cpu_power(sd->groups, group->__cpu_power); |
89c4710e SS |
6279 | group = group->next; |
6280 | } while (group != child->groups); | |
6281 | } | |
6282 | ||
1da177e4 | 6283 | /* |
1a20ff27 DG |
6284 | * Build sched domains for a given set of cpus and attach the sched domains |
6285 | * to the individual cpus | |
1da177e4 | 6286 | */ |
51888ca2 | 6287 | static int build_sched_domains(const cpumask_t *cpu_map) |
1da177e4 LT |
6288 | { |
6289 | int i; | |
57d885fe | 6290 | struct root_domain *rd; |
d1b55138 JH |
6291 | #ifdef CONFIG_NUMA |
6292 | struct sched_group **sched_group_nodes = NULL; | |
6711cab4 | 6293 | int sd_allnodes = 0; |
d1b55138 JH |
6294 | |
6295 | /* | |
6296 | * Allocate the per-node list of sched groups | |
6297 | */ | |
5cf9f062 | 6298 | sched_group_nodes = kcalloc(MAX_NUMNODES, sizeof(struct sched_group *), |
41a2d6cf | 6299 | GFP_KERNEL); |
d1b55138 JH |
6300 | if (!sched_group_nodes) { |
6301 | printk(KERN_WARNING "Can not alloc sched group node list\n"); | |
51888ca2 | 6302 | return -ENOMEM; |
d1b55138 JH |
6303 | } |
6304 | sched_group_nodes_bycpu[first_cpu(*cpu_map)] = sched_group_nodes; | |
6305 | #endif | |
1da177e4 | 6306 | |
57d885fe GH |
6307 | rd = alloc_rootdomain(cpu_map); |
6308 | if (!rd) { | |
6309 | printk(KERN_WARNING "Cannot alloc root domain\n"); | |
6310 | return -ENOMEM; | |
6311 | } | |
6312 | ||
1da177e4 | 6313 | /* |
1a20ff27 | 6314 | * Set up domains for cpus specified by the cpu_map. |
1da177e4 | 6315 | */ |
1a20ff27 | 6316 | for_each_cpu_mask(i, *cpu_map) { |
1da177e4 LT |
6317 | struct sched_domain *sd = NULL, *p; |
6318 | cpumask_t nodemask = node_to_cpumask(cpu_to_node(i)); | |
6319 | ||
1a20ff27 | 6320 | cpus_and(nodemask, nodemask, *cpu_map); |
1da177e4 LT |
6321 | |
6322 | #ifdef CONFIG_NUMA | |
dd41f596 IM |
6323 | if (cpus_weight(*cpu_map) > |
6324 | SD_NODES_PER_DOMAIN*cpus_weight(nodemask)) { | |
9c1cfda2 JH |
6325 | sd = &per_cpu(allnodes_domains, i); |
6326 | *sd = SD_ALLNODES_INIT; | |
6327 | sd->span = *cpu_map; | |
6711cab4 | 6328 | cpu_to_allnodes_group(i, cpu_map, &sd->groups); |
9c1cfda2 | 6329 | p = sd; |
6711cab4 | 6330 | sd_allnodes = 1; |
9c1cfda2 JH |
6331 | } else |
6332 | p = NULL; | |
6333 | ||
1da177e4 | 6334 | sd = &per_cpu(node_domains, i); |
1da177e4 | 6335 | *sd = SD_NODE_INIT; |
9c1cfda2 JH |
6336 | sd->span = sched_domain_node_span(cpu_to_node(i)); |
6337 | sd->parent = p; | |
1a848870 SS |
6338 | if (p) |
6339 | p->child = sd; | |
9c1cfda2 | 6340 | cpus_and(sd->span, sd->span, *cpu_map); |
1da177e4 LT |
6341 | #endif |
6342 | ||
6343 | p = sd; | |
6344 | sd = &per_cpu(phys_domains, i); | |
1da177e4 LT |
6345 | *sd = SD_CPU_INIT; |
6346 | sd->span = nodemask; | |
6347 | sd->parent = p; | |
1a848870 SS |
6348 | if (p) |
6349 | p->child = sd; | |
6711cab4 | 6350 | cpu_to_phys_group(i, cpu_map, &sd->groups); |
1da177e4 | 6351 | |
1e9f28fa SS |
6352 | #ifdef CONFIG_SCHED_MC |
6353 | p = sd; | |
6354 | sd = &per_cpu(core_domains, i); | |
1e9f28fa SS |
6355 | *sd = SD_MC_INIT; |
6356 | sd->span = cpu_coregroup_map(i); | |
6357 | cpus_and(sd->span, sd->span, *cpu_map); | |
6358 | sd->parent = p; | |
1a848870 | 6359 | p->child = sd; |
6711cab4 | 6360 | cpu_to_core_group(i, cpu_map, &sd->groups); |
1e9f28fa SS |
6361 | #endif |
6362 | ||
1da177e4 LT |
6363 | #ifdef CONFIG_SCHED_SMT |
6364 | p = sd; | |
6365 | sd = &per_cpu(cpu_domains, i); | |
1da177e4 | 6366 | *sd = SD_SIBLING_INIT; |
d5a7430d | 6367 | sd->span = per_cpu(cpu_sibling_map, i); |
1a20ff27 | 6368 | cpus_and(sd->span, sd->span, *cpu_map); |
1da177e4 | 6369 | sd->parent = p; |
1a848870 | 6370 | p->child = sd; |
6711cab4 | 6371 | cpu_to_cpu_group(i, cpu_map, &sd->groups); |
1da177e4 LT |
6372 | #endif |
6373 | } | |
6374 | ||
6375 | #ifdef CONFIG_SCHED_SMT | |
6376 | /* Set up CPU (sibling) groups */ | |
9c1cfda2 | 6377 | for_each_cpu_mask(i, *cpu_map) { |
d5a7430d | 6378 | cpumask_t this_sibling_map = per_cpu(cpu_sibling_map, i); |
1a20ff27 | 6379 | cpus_and(this_sibling_map, this_sibling_map, *cpu_map); |
1da177e4 LT |
6380 | if (i != first_cpu(this_sibling_map)) |
6381 | continue; | |
6382 | ||
dd41f596 IM |
6383 | init_sched_build_groups(this_sibling_map, cpu_map, |
6384 | &cpu_to_cpu_group); | |
1da177e4 LT |
6385 | } |
6386 | #endif | |
6387 | ||
1e9f28fa SS |
6388 | #ifdef CONFIG_SCHED_MC |
6389 | /* Set up multi-core groups */ | |
6390 | for_each_cpu_mask(i, *cpu_map) { | |
6391 | cpumask_t this_core_map = cpu_coregroup_map(i); | |
6392 | cpus_and(this_core_map, this_core_map, *cpu_map); | |
6393 | if (i != first_cpu(this_core_map)) | |
6394 | continue; | |
dd41f596 IM |
6395 | init_sched_build_groups(this_core_map, cpu_map, |
6396 | &cpu_to_core_group); | |
1e9f28fa SS |
6397 | } |
6398 | #endif | |
6399 | ||
1da177e4 LT |
6400 | /* Set up physical groups */ |
6401 | for (i = 0; i < MAX_NUMNODES; i++) { | |
6402 | cpumask_t nodemask = node_to_cpumask(i); | |
6403 | ||
1a20ff27 | 6404 | cpus_and(nodemask, nodemask, *cpu_map); |
1da177e4 LT |
6405 | if (cpus_empty(nodemask)) |
6406 | continue; | |
6407 | ||
6711cab4 | 6408 | init_sched_build_groups(nodemask, cpu_map, &cpu_to_phys_group); |
1da177e4 LT |
6409 | } |
6410 | ||
6411 | #ifdef CONFIG_NUMA | |
6412 | /* Set up node groups */ | |
6711cab4 | 6413 | if (sd_allnodes) |
dd41f596 IM |
6414 | init_sched_build_groups(*cpu_map, cpu_map, |
6415 | &cpu_to_allnodes_group); | |
9c1cfda2 JH |
6416 | |
6417 | for (i = 0; i < MAX_NUMNODES; i++) { | |
6418 | /* Set up node groups */ | |
6419 | struct sched_group *sg, *prev; | |
6420 | cpumask_t nodemask = node_to_cpumask(i); | |
6421 | cpumask_t domainspan; | |
6422 | cpumask_t covered = CPU_MASK_NONE; | |
6423 | int j; | |
6424 | ||
6425 | cpus_and(nodemask, nodemask, *cpu_map); | |
d1b55138 JH |
6426 | if (cpus_empty(nodemask)) { |
6427 | sched_group_nodes[i] = NULL; | |
9c1cfda2 | 6428 | continue; |
d1b55138 | 6429 | } |
9c1cfda2 JH |
6430 | |
6431 | domainspan = sched_domain_node_span(i); | |
6432 | cpus_and(domainspan, domainspan, *cpu_map); | |
6433 | ||
15f0b676 | 6434 | sg = kmalloc_node(sizeof(struct sched_group), GFP_KERNEL, i); |
51888ca2 SV |
6435 | if (!sg) { |
6436 | printk(KERN_WARNING "Can not alloc domain group for " | |
6437 | "node %d\n", i); | |
6438 | goto error; | |
6439 | } | |
9c1cfda2 JH |
6440 | sched_group_nodes[i] = sg; |
6441 | for_each_cpu_mask(j, nodemask) { | |
6442 | struct sched_domain *sd; | |
9761eea8 | 6443 | |
9c1cfda2 JH |
6444 | sd = &per_cpu(node_domains, j); |
6445 | sd->groups = sg; | |
9c1cfda2 | 6446 | } |
5517d86b | 6447 | sg->__cpu_power = 0; |
9c1cfda2 | 6448 | sg->cpumask = nodemask; |
51888ca2 | 6449 | sg->next = sg; |
9c1cfda2 JH |
6450 | cpus_or(covered, covered, nodemask); |
6451 | prev = sg; | |
6452 | ||
6453 | for (j = 0; j < MAX_NUMNODES; j++) { | |
6454 | cpumask_t tmp, notcovered; | |
6455 | int n = (i + j) % MAX_NUMNODES; | |
6456 | ||
6457 | cpus_complement(notcovered, covered); | |
6458 | cpus_and(tmp, notcovered, *cpu_map); | |
6459 | cpus_and(tmp, tmp, domainspan); | |
6460 | if (cpus_empty(tmp)) | |
6461 | break; | |
6462 | ||
6463 | nodemask = node_to_cpumask(n); | |
6464 | cpus_and(tmp, tmp, nodemask); | |
6465 | if (cpus_empty(tmp)) | |
6466 | continue; | |
6467 | ||
15f0b676 SV |
6468 | sg = kmalloc_node(sizeof(struct sched_group), |
6469 | GFP_KERNEL, i); | |
9c1cfda2 JH |
6470 | if (!sg) { |
6471 | printk(KERN_WARNING | |
6472 | "Can not alloc domain group for node %d\n", j); | |
51888ca2 | 6473 | goto error; |
9c1cfda2 | 6474 | } |
5517d86b | 6475 | sg->__cpu_power = 0; |
9c1cfda2 | 6476 | sg->cpumask = tmp; |
51888ca2 | 6477 | sg->next = prev->next; |
9c1cfda2 JH |
6478 | cpus_or(covered, covered, tmp); |
6479 | prev->next = sg; | |
6480 | prev = sg; | |
6481 | } | |
9c1cfda2 | 6482 | } |
1da177e4 LT |
6483 | #endif |
6484 | ||
6485 | /* Calculate CPU power for physical packages and nodes */ | |
5c45bf27 | 6486 | #ifdef CONFIG_SCHED_SMT |
1a20ff27 | 6487 | for_each_cpu_mask(i, *cpu_map) { |
dd41f596 IM |
6488 | struct sched_domain *sd = &per_cpu(cpu_domains, i); |
6489 | ||
89c4710e | 6490 | init_sched_groups_power(i, sd); |
5c45bf27 | 6491 | } |
1da177e4 | 6492 | #endif |
1e9f28fa | 6493 | #ifdef CONFIG_SCHED_MC |
5c45bf27 | 6494 | for_each_cpu_mask(i, *cpu_map) { |
dd41f596 IM |
6495 | struct sched_domain *sd = &per_cpu(core_domains, i); |
6496 | ||
89c4710e | 6497 | init_sched_groups_power(i, sd); |
5c45bf27 SS |
6498 | } |
6499 | #endif | |
1e9f28fa | 6500 | |
5c45bf27 | 6501 | for_each_cpu_mask(i, *cpu_map) { |
dd41f596 IM |
6502 | struct sched_domain *sd = &per_cpu(phys_domains, i); |
6503 | ||
89c4710e | 6504 | init_sched_groups_power(i, sd); |
1da177e4 LT |
6505 | } |
6506 | ||
9c1cfda2 | 6507 | #ifdef CONFIG_NUMA |
08069033 SS |
6508 | for (i = 0; i < MAX_NUMNODES; i++) |
6509 | init_numa_sched_groups_power(sched_group_nodes[i]); | |
9c1cfda2 | 6510 | |
6711cab4 SS |
6511 | if (sd_allnodes) { |
6512 | struct sched_group *sg; | |
f712c0c7 | 6513 | |
6711cab4 | 6514 | cpu_to_allnodes_group(first_cpu(*cpu_map), cpu_map, &sg); |
f712c0c7 SS |
6515 | init_numa_sched_groups_power(sg); |
6516 | } | |
9c1cfda2 JH |
6517 | #endif |
6518 | ||
1da177e4 | 6519 | /* Attach the domains */ |
1a20ff27 | 6520 | for_each_cpu_mask(i, *cpu_map) { |
1da177e4 LT |
6521 | struct sched_domain *sd; |
6522 | #ifdef CONFIG_SCHED_SMT | |
6523 | sd = &per_cpu(cpu_domains, i); | |
1e9f28fa SS |
6524 | #elif defined(CONFIG_SCHED_MC) |
6525 | sd = &per_cpu(core_domains, i); | |
1da177e4 LT |
6526 | #else |
6527 | sd = &per_cpu(phys_domains, i); | |
6528 | #endif | |
57d885fe | 6529 | cpu_attach_domain(sd, rd, i); |
1da177e4 | 6530 | } |
51888ca2 SV |
6531 | |
6532 | return 0; | |
6533 | ||
a616058b | 6534 | #ifdef CONFIG_NUMA |
51888ca2 SV |
6535 | error: |
6536 | free_sched_groups(cpu_map); | |
6537 | return -ENOMEM; | |
a616058b | 6538 | #endif |
1da177e4 | 6539 | } |
029190c5 PJ |
6540 | |
6541 | static cpumask_t *doms_cur; /* current sched domains */ | |
6542 | static int ndoms_cur; /* number of sched domains in 'doms_cur' */ | |
6543 | ||
6544 | /* | |
6545 | * Special case: If a kmalloc of a doms_cur partition (array of | |
6546 | * cpumask_t) fails, then fallback to a single sched domain, | |
6547 | * as determined by the single cpumask_t fallback_doms. | |
6548 | */ | |
6549 | static cpumask_t fallback_doms; | |
6550 | ||
1a20ff27 | 6551 | /* |
41a2d6cf | 6552 | * Set up scheduler domains and groups. Callers must hold the hotplug lock. |
029190c5 PJ |
6553 | * For now this just excludes isolated cpus, but could be used to |
6554 | * exclude other special cases in the future. | |
1a20ff27 | 6555 | */ |
51888ca2 | 6556 | static int arch_init_sched_domains(const cpumask_t *cpu_map) |
1a20ff27 | 6557 | { |
7378547f MM |
6558 | int err; |
6559 | ||
029190c5 PJ |
6560 | ndoms_cur = 1; |
6561 | doms_cur = kmalloc(sizeof(cpumask_t), GFP_KERNEL); | |
6562 | if (!doms_cur) | |
6563 | doms_cur = &fallback_doms; | |
6564 | cpus_andnot(*doms_cur, *cpu_map, cpu_isolated_map); | |
7378547f | 6565 | err = build_sched_domains(doms_cur); |
6382bc90 | 6566 | register_sched_domain_sysctl(); |
7378547f MM |
6567 | |
6568 | return err; | |
1a20ff27 DG |
6569 | } |
6570 | ||
6571 | static void arch_destroy_sched_domains(const cpumask_t *cpu_map) | |
1da177e4 | 6572 | { |
51888ca2 | 6573 | free_sched_groups(cpu_map); |
9c1cfda2 | 6574 | } |
1da177e4 | 6575 | |
1a20ff27 DG |
6576 | /* |
6577 | * Detach sched domains from a group of cpus specified in cpu_map | |
6578 | * These cpus will now be attached to the NULL domain | |
6579 | */ | |
858119e1 | 6580 | static void detach_destroy_domains(const cpumask_t *cpu_map) |
1a20ff27 DG |
6581 | { |
6582 | int i; | |
6583 | ||
6382bc90 MM |
6584 | unregister_sched_domain_sysctl(); |
6585 | ||
1a20ff27 | 6586 | for_each_cpu_mask(i, *cpu_map) |
57d885fe | 6587 | cpu_attach_domain(NULL, &def_root_domain, i); |
1a20ff27 DG |
6588 | synchronize_sched(); |
6589 | arch_destroy_sched_domains(cpu_map); | |
6590 | } | |
6591 | ||
029190c5 PJ |
6592 | /* |
6593 | * Partition sched domains as specified by the 'ndoms_new' | |
41a2d6cf | 6594 | * cpumasks in the array doms_new[] of cpumasks. This compares |
029190c5 PJ |
6595 | * doms_new[] to the current sched domain partitioning, doms_cur[]. |
6596 | * It destroys each deleted domain and builds each new domain. | |
6597 | * | |
6598 | * 'doms_new' is an array of cpumask_t's of length 'ndoms_new'. | |
41a2d6cf IM |
6599 | * The masks don't intersect (don't overlap.) We should setup one |
6600 | * sched domain for each mask. CPUs not in any of the cpumasks will | |
6601 | * not be load balanced. If the same cpumask appears both in the | |
029190c5 PJ |
6602 | * current 'doms_cur' domains and in the new 'doms_new', we can leave |
6603 | * it as it is. | |
6604 | * | |
41a2d6cf IM |
6605 | * The passed in 'doms_new' should be kmalloc'd. This routine takes |
6606 | * ownership of it and will kfree it when done with it. If the caller | |
029190c5 PJ |
6607 | * failed the kmalloc call, then it can pass in doms_new == NULL, |
6608 | * and partition_sched_domains() will fallback to the single partition | |
6609 | * 'fallback_doms'. | |
6610 | * | |
6611 | * Call with hotplug lock held | |
6612 | */ | |
6613 | void partition_sched_domains(int ndoms_new, cpumask_t *doms_new) | |
6614 | { | |
6615 | int i, j; | |
6616 | ||
a1835615 SV |
6617 | lock_doms_cur(); |
6618 | ||
7378547f MM |
6619 | /* always unregister in case we don't destroy any domains */ |
6620 | unregister_sched_domain_sysctl(); | |
6621 | ||
029190c5 PJ |
6622 | if (doms_new == NULL) { |
6623 | ndoms_new = 1; | |
6624 | doms_new = &fallback_doms; | |
6625 | cpus_andnot(doms_new[0], cpu_online_map, cpu_isolated_map); | |
6626 | } | |
6627 | ||
6628 | /* Destroy deleted domains */ | |
6629 | for (i = 0; i < ndoms_cur; i++) { | |
6630 | for (j = 0; j < ndoms_new; j++) { | |
6631 | if (cpus_equal(doms_cur[i], doms_new[j])) | |
6632 | goto match1; | |
6633 | } | |
6634 | /* no match - a current sched domain not in new doms_new[] */ | |
6635 | detach_destroy_domains(doms_cur + i); | |
6636 | match1: | |
6637 | ; | |
6638 | } | |
6639 | ||
6640 | /* Build new domains */ | |
6641 | for (i = 0; i < ndoms_new; i++) { | |
6642 | for (j = 0; j < ndoms_cur; j++) { | |
6643 | if (cpus_equal(doms_new[i], doms_cur[j])) | |
6644 | goto match2; | |
6645 | } | |
6646 | /* no match - add a new doms_new */ | |
6647 | build_sched_domains(doms_new + i); | |
6648 | match2: | |
6649 | ; | |
6650 | } | |
6651 | ||
6652 | /* Remember the new sched domains */ | |
6653 | if (doms_cur != &fallback_doms) | |
6654 | kfree(doms_cur); | |
6655 | doms_cur = doms_new; | |
6656 | ndoms_cur = ndoms_new; | |
7378547f MM |
6657 | |
6658 | register_sched_domain_sysctl(); | |
a1835615 SV |
6659 | |
6660 | unlock_doms_cur(); | |
029190c5 PJ |
6661 | } |
6662 | ||
5c45bf27 | 6663 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) |
6707de00 | 6664 | static int arch_reinit_sched_domains(void) |
5c45bf27 SS |
6665 | { |
6666 | int err; | |
6667 | ||
95402b38 | 6668 | get_online_cpus(); |
5c45bf27 SS |
6669 | detach_destroy_domains(&cpu_online_map); |
6670 | err = arch_init_sched_domains(&cpu_online_map); | |
95402b38 | 6671 | put_online_cpus(); |
5c45bf27 SS |
6672 | |
6673 | return err; | |
6674 | } | |
6675 | ||
6676 | static ssize_t sched_power_savings_store(const char *buf, size_t count, int smt) | |
6677 | { | |
6678 | int ret; | |
6679 | ||
6680 | if (buf[0] != '0' && buf[0] != '1') | |
6681 | return -EINVAL; | |
6682 | ||
6683 | if (smt) | |
6684 | sched_smt_power_savings = (buf[0] == '1'); | |
6685 | else | |
6686 | sched_mc_power_savings = (buf[0] == '1'); | |
6687 | ||
6688 | ret = arch_reinit_sched_domains(); | |
6689 | ||
6690 | return ret ? ret : count; | |
6691 | } | |
6692 | ||
5c45bf27 SS |
6693 | #ifdef CONFIG_SCHED_MC |
6694 | static ssize_t sched_mc_power_savings_show(struct sys_device *dev, char *page) | |
6695 | { | |
6696 | return sprintf(page, "%u\n", sched_mc_power_savings); | |
6697 | } | |
48f24c4d IM |
6698 | static ssize_t sched_mc_power_savings_store(struct sys_device *dev, |
6699 | const char *buf, size_t count) | |
5c45bf27 SS |
6700 | { |
6701 | return sched_power_savings_store(buf, count, 0); | |
6702 | } | |
6707de00 AB |
6703 | static SYSDEV_ATTR(sched_mc_power_savings, 0644, sched_mc_power_savings_show, |
6704 | sched_mc_power_savings_store); | |
5c45bf27 SS |
6705 | #endif |
6706 | ||
6707 | #ifdef CONFIG_SCHED_SMT | |
6708 | static ssize_t sched_smt_power_savings_show(struct sys_device *dev, char *page) | |
6709 | { | |
6710 | return sprintf(page, "%u\n", sched_smt_power_savings); | |
6711 | } | |
48f24c4d IM |
6712 | static ssize_t sched_smt_power_savings_store(struct sys_device *dev, |
6713 | const char *buf, size_t count) | |
5c45bf27 SS |
6714 | { |
6715 | return sched_power_savings_store(buf, count, 1); | |
6716 | } | |
6707de00 AB |
6717 | static SYSDEV_ATTR(sched_smt_power_savings, 0644, sched_smt_power_savings_show, |
6718 | sched_smt_power_savings_store); | |
6719 | #endif | |
6720 | ||
6721 | int sched_create_sysfs_power_savings_entries(struct sysdev_class *cls) | |
6722 | { | |
6723 | int err = 0; | |
6724 | ||
6725 | #ifdef CONFIG_SCHED_SMT | |
6726 | if (smt_capable()) | |
6727 | err = sysfs_create_file(&cls->kset.kobj, | |
6728 | &attr_sched_smt_power_savings.attr); | |
6729 | #endif | |
6730 | #ifdef CONFIG_SCHED_MC | |
6731 | if (!err && mc_capable()) | |
6732 | err = sysfs_create_file(&cls->kset.kobj, | |
6733 | &attr_sched_mc_power_savings.attr); | |
6734 | #endif | |
6735 | return err; | |
6736 | } | |
5c45bf27 SS |
6737 | #endif |
6738 | ||
1da177e4 | 6739 | /* |
41a2d6cf | 6740 | * Force a reinitialization of the sched domains hierarchy. The domains |
1da177e4 | 6741 | * and groups cannot be updated in place without racing with the balancing |
41c7ce9a | 6742 | * code, so we temporarily attach all running cpus to the NULL domain |
1da177e4 LT |
6743 | * which will prevent rebalancing while the sched domains are recalculated. |
6744 | */ | |
6745 | static int update_sched_domains(struct notifier_block *nfb, | |
6746 | unsigned long action, void *hcpu) | |
6747 | { | |
1da177e4 LT |
6748 | switch (action) { |
6749 | case CPU_UP_PREPARE: | |
8bb78442 | 6750 | case CPU_UP_PREPARE_FROZEN: |
1da177e4 | 6751 | case CPU_DOWN_PREPARE: |
8bb78442 | 6752 | case CPU_DOWN_PREPARE_FROZEN: |
1a20ff27 | 6753 | detach_destroy_domains(&cpu_online_map); |
1da177e4 LT |
6754 | return NOTIFY_OK; |
6755 | ||
6756 | case CPU_UP_CANCELED: | |
8bb78442 | 6757 | case CPU_UP_CANCELED_FROZEN: |
1da177e4 | 6758 | case CPU_DOWN_FAILED: |
8bb78442 | 6759 | case CPU_DOWN_FAILED_FROZEN: |
1da177e4 | 6760 | case CPU_ONLINE: |
8bb78442 | 6761 | case CPU_ONLINE_FROZEN: |
1da177e4 | 6762 | case CPU_DEAD: |
8bb78442 | 6763 | case CPU_DEAD_FROZEN: |
1da177e4 LT |
6764 | /* |
6765 | * Fall through and re-initialise the domains. | |
6766 | */ | |
6767 | break; | |
6768 | default: | |
6769 | return NOTIFY_DONE; | |
6770 | } | |
6771 | ||
6772 | /* The hotplug lock is already held by cpu_up/cpu_down */ | |
1a20ff27 | 6773 | arch_init_sched_domains(&cpu_online_map); |
1da177e4 LT |
6774 | |
6775 | return NOTIFY_OK; | |
6776 | } | |
1da177e4 LT |
6777 | |
6778 | void __init sched_init_smp(void) | |
6779 | { | |
5c1e1767 NP |
6780 | cpumask_t non_isolated_cpus; |
6781 | ||
95402b38 | 6782 | get_online_cpus(); |
1a20ff27 | 6783 | arch_init_sched_domains(&cpu_online_map); |
e5e5673f | 6784 | cpus_andnot(non_isolated_cpus, cpu_possible_map, cpu_isolated_map); |
5c1e1767 NP |
6785 | if (cpus_empty(non_isolated_cpus)) |
6786 | cpu_set(smp_processor_id(), non_isolated_cpus); | |
95402b38 | 6787 | put_online_cpus(); |
1da177e4 LT |
6788 | /* XXX: Theoretical race here - CPU may be hotplugged now */ |
6789 | hotcpu_notifier(update_sched_domains, 0); | |
5c1e1767 NP |
6790 | |
6791 | /* Move init over to a non-isolated CPU */ | |
6792 | if (set_cpus_allowed(current, non_isolated_cpus) < 0) | |
6793 | BUG(); | |
19978ca6 | 6794 | sched_init_granularity(); |
6b2d7700 SV |
6795 | |
6796 | #ifdef CONFIG_FAIR_GROUP_SCHED | |
6797 | if (nr_cpu_ids == 1) | |
6798 | return; | |
6799 | ||
6800 | lb_monitor_task = kthread_create(load_balance_monitor, NULL, | |
6801 | "group_balance"); | |
6802 | if (!IS_ERR(lb_monitor_task)) { | |
6803 | lb_monitor_task->flags |= PF_NOFREEZE; | |
6804 | wake_up_process(lb_monitor_task); | |
6805 | } else { | |
6806 | printk(KERN_ERR "Could not create load balance monitor thread" | |
6807 | "(error = %ld) \n", PTR_ERR(lb_monitor_task)); | |
6808 | } | |
6809 | #endif | |
1da177e4 LT |
6810 | } |
6811 | #else | |
6812 | void __init sched_init_smp(void) | |
6813 | { | |
19978ca6 | 6814 | sched_init_granularity(); |
1da177e4 LT |
6815 | } |
6816 | #endif /* CONFIG_SMP */ | |
6817 | ||
6818 | int in_sched_functions(unsigned long addr) | |
6819 | { | |
1da177e4 LT |
6820 | return in_lock_functions(addr) || |
6821 | (addr >= (unsigned long)__sched_text_start | |
6822 | && addr < (unsigned long)__sched_text_end); | |
6823 | } | |
6824 | ||
a9957449 | 6825 | static void init_cfs_rq(struct cfs_rq *cfs_rq, struct rq *rq) |
dd41f596 IM |
6826 | { |
6827 | cfs_rq->tasks_timeline = RB_ROOT; | |
dd41f596 IM |
6828 | #ifdef CONFIG_FAIR_GROUP_SCHED |
6829 | cfs_rq->rq = rq; | |
6830 | #endif | |
67e9fb2a | 6831 | cfs_rq->min_vruntime = (u64)(-(1LL << 20)); |
dd41f596 IM |
6832 | } |
6833 | ||
1da177e4 LT |
6834 | void __init sched_init(void) |
6835 | { | |
476f3534 | 6836 | int highest_cpu = 0; |
dd41f596 IM |
6837 | int i, j; |
6838 | ||
57d885fe GH |
6839 | #ifdef CONFIG_SMP |
6840 | init_defrootdomain(); | |
6841 | #endif | |
6842 | ||
0a945022 | 6843 | for_each_possible_cpu(i) { |
dd41f596 | 6844 | struct rt_prio_array *array; |
70b97a7f | 6845 | struct rq *rq; |
1da177e4 LT |
6846 | |
6847 | rq = cpu_rq(i); | |
6848 | spin_lock_init(&rq->lock); | |
fcb99371 | 6849 | lockdep_set_class(&rq->lock, &rq->rq_lock_key); |
7897986b | 6850 | rq->nr_running = 0; |
dd41f596 IM |
6851 | rq->clock = 1; |
6852 | init_cfs_rq(&rq->cfs, rq); | |
6853 | #ifdef CONFIG_FAIR_GROUP_SCHED | |
6854 | INIT_LIST_HEAD(&rq->leaf_cfs_rq_list); | |
3a252015 IM |
6855 | { |
6856 | struct cfs_rq *cfs_rq = &per_cpu(init_cfs_rq, i); | |
6857 | struct sched_entity *se = | |
6858 | &per_cpu(init_sched_entity, i); | |
6859 | ||
6860 | init_cfs_rq_p[i] = cfs_rq; | |
6861 | init_cfs_rq(cfs_rq, rq); | |
4cf86d77 | 6862 | cfs_rq->tg = &init_task_group; |
3a252015 | 6863 | list_add(&cfs_rq->leaf_cfs_rq_list, |
29f59db3 SV |
6864 | &rq->leaf_cfs_rq_list); |
6865 | ||
3a252015 IM |
6866 | init_sched_entity_p[i] = se; |
6867 | se->cfs_rq = &rq->cfs; | |
6868 | se->my_q = cfs_rq; | |
4cf86d77 | 6869 | se->load.weight = init_task_group_load; |
9b5b7751 | 6870 | se->load.inv_weight = |
4cf86d77 | 6871 | div64_64(1ULL<<32, init_task_group_load); |
3a252015 IM |
6872 | se->parent = NULL; |
6873 | } | |
4cf86d77 | 6874 | init_task_group.shares = init_task_group_load; |
dd41f596 | 6875 | #endif |
1da177e4 | 6876 | |
dd41f596 IM |
6877 | for (j = 0; j < CPU_LOAD_IDX_MAX; j++) |
6878 | rq->cpu_load[j] = 0; | |
1da177e4 | 6879 | #ifdef CONFIG_SMP |
41c7ce9a | 6880 | rq->sd = NULL; |
57d885fe GH |
6881 | rq->rd = NULL; |
6882 | rq_attach_root(rq, &def_root_domain); | |
1da177e4 | 6883 | rq->active_balance = 0; |
dd41f596 | 6884 | rq->next_balance = jiffies; |
1da177e4 | 6885 | rq->push_cpu = 0; |
0a2966b4 | 6886 | rq->cpu = i; |
1da177e4 LT |
6887 | rq->migration_thread = NULL; |
6888 | INIT_LIST_HEAD(&rq->migration_queue); | |
764a9d6f | 6889 | rq->rt.highest_prio = MAX_RT_PRIO; |
a22d7fc1 | 6890 | rq->rt.overloaded = 0; |
1da177e4 LT |
6891 | #endif |
6892 | atomic_set(&rq->nr_iowait, 0); | |
6893 | ||
dd41f596 IM |
6894 | array = &rq->rt.active; |
6895 | for (j = 0; j < MAX_RT_PRIO; j++) { | |
6896 | INIT_LIST_HEAD(array->queue + j); | |
6897 | __clear_bit(j, array->bitmap); | |
1da177e4 | 6898 | } |
476f3534 | 6899 | highest_cpu = i; |
dd41f596 IM |
6900 | /* delimiter for bitsearch: */ |
6901 | __set_bit(MAX_RT_PRIO, array->bitmap); | |
1da177e4 LT |
6902 | } |
6903 | ||
2dd73a4f | 6904 | set_load_weight(&init_task); |
b50f60ce | 6905 | |
e107be36 AK |
6906 | #ifdef CONFIG_PREEMPT_NOTIFIERS |
6907 | INIT_HLIST_HEAD(&init_task.preempt_notifiers); | |
6908 | #endif | |
6909 | ||
c9819f45 | 6910 | #ifdef CONFIG_SMP |
476f3534 | 6911 | nr_cpu_ids = highest_cpu + 1; |
c9819f45 CL |
6912 | open_softirq(SCHED_SOFTIRQ, run_rebalance_domains, NULL); |
6913 | #endif | |
6914 | ||
b50f60ce HC |
6915 | #ifdef CONFIG_RT_MUTEXES |
6916 | plist_head_init(&init_task.pi_waiters, &init_task.pi_lock); | |
6917 | #endif | |
6918 | ||
1da177e4 LT |
6919 | /* |
6920 | * The boot idle thread does lazy MMU switching as well: | |
6921 | */ | |
6922 | atomic_inc(&init_mm.mm_count); | |
6923 | enter_lazy_tlb(&init_mm, current); | |
6924 | ||
6925 | /* | |
6926 | * Make us the idle thread. Technically, schedule() should not be | |
6927 | * called from this thread, however somewhere below it might be, | |
6928 | * but because we are the idle thread, we just pick up running again | |
6929 | * when this runqueue becomes "idle". | |
6930 | */ | |
6931 | init_idle(current, smp_processor_id()); | |
dd41f596 IM |
6932 | /* |
6933 | * During early bootup we pretend to be a normal task: | |
6934 | */ | |
6935 | current->sched_class = &fair_sched_class; | |
1da177e4 LT |
6936 | } |
6937 | ||
6938 | #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP | |
6939 | void __might_sleep(char *file, int line) | |
6940 | { | |
48f24c4d | 6941 | #ifdef in_atomic |
1da177e4 LT |
6942 | static unsigned long prev_jiffy; /* ratelimiting */ |
6943 | ||
6944 | if ((in_atomic() || irqs_disabled()) && | |
6945 | system_state == SYSTEM_RUNNING && !oops_in_progress) { | |
6946 | if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy) | |
6947 | return; | |
6948 | prev_jiffy = jiffies; | |
91368d73 | 6949 | printk(KERN_ERR "BUG: sleeping function called from invalid" |
1da177e4 LT |
6950 | " context at %s:%d\n", file, line); |
6951 | printk("in_atomic():%d, irqs_disabled():%d\n", | |
6952 | in_atomic(), irqs_disabled()); | |
a4c410f0 | 6953 | debug_show_held_locks(current); |
3117df04 IM |
6954 | if (irqs_disabled()) |
6955 | print_irqtrace_events(current); | |
1da177e4 LT |
6956 | dump_stack(); |
6957 | } | |
6958 | #endif | |
6959 | } | |
6960 | EXPORT_SYMBOL(__might_sleep); | |
6961 | #endif | |
6962 | ||
6963 | #ifdef CONFIG_MAGIC_SYSRQ | |
3a5e4dc1 AK |
6964 | static void normalize_task(struct rq *rq, struct task_struct *p) |
6965 | { | |
6966 | int on_rq; | |
6967 | update_rq_clock(rq); | |
6968 | on_rq = p->se.on_rq; | |
6969 | if (on_rq) | |
6970 | deactivate_task(rq, p, 0); | |
6971 | __setscheduler(rq, p, SCHED_NORMAL, 0); | |
6972 | if (on_rq) { | |
6973 | activate_task(rq, p, 0); | |
6974 | resched_task(rq->curr); | |
6975 | } | |
6976 | } | |
6977 | ||
1da177e4 LT |
6978 | void normalize_rt_tasks(void) |
6979 | { | |
a0f98a1c | 6980 | struct task_struct *g, *p; |
1da177e4 | 6981 | unsigned long flags; |
70b97a7f | 6982 | struct rq *rq; |
1da177e4 LT |
6983 | |
6984 | read_lock_irq(&tasklist_lock); | |
a0f98a1c | 6985 | do_each_thread(g, p) { |
178be793 IM |
6986 | /* |
6987 | * Only normalize user tasks: | |
6988 | */ | |
6989 | if (!p->mm) | |
6990 | continue; | |
6991 | ||
6cfb0d5d | 6992 | p->se.exec_start = 0; |
6cfb0d5d | 6993 | #ifdef CONFIG_SCHEDSTATS |
dd41f596 | 6994 | p->se.wait_start = 0; |
dd41f596 | 6995 | p->se.sleep_start = 0; |
dd41f596 | 6996 | p->se.block_start = 0; |
6cfb0d5d | 6997 | #endif |
dd41f596 IM |
6998 | task_rq(p)->clock = 0; |
6999 | ||
7000 | if (!rt_task(p)) { | |
7001 | /* | |
7002 | * Renice negative nice level userspace | |
7003 | * tasks back to 0: | |
7004 | */ | |
7005 | if (TASK_NICE(p) < 0 && p->mm) | |
7006 | set_user_nice(p, 0); | |
1da177e4 | 7007 | continue; |
dd41f596 | 7008 | } |
1da177e4 | 7009 | |
b29739f9 IM |
7010 | spin_lock_irqsave(&p->pi_lock, flags); |
7011 | rq = __task_rq_lock(p); | |
1da177e4 | 7012 | |
178be793 | 7013 | normalize_task(rq, p); |
3a5e4dc1 | 7014 | |
b29739f9 IM |
7015 | __task_rq_unlock(rq); |
7016 | spin_unlock_irqrestore(&p->pi_lock, flags); | |
a0f98a1c IM |
7017 | } while_each_thread(g, p); |
7018 | ||
1da177e4 LT |
7019 | read_unlock_irq(&tasklist_lock); |
7020 | } | |
7021 | ||
7022 | #endif /* CONFIG_MAGIC_SYSRQ */ | |
1df5c10a LT |
7023 | |
7024 | #ifdef CONFIG_IA64 | |
7025 | /* | |
7026 | * These functions are only useful for the IA64 MCA handling. | |
7027 | * | |
7028 | * They can only be called when the whole system has been | |
7029 | * stopped - every CPU needs to be quiescent, and no scheduling | |
7030 | * activity can take place. Using them for anything else would | |
7031 | * be a serious bug, and as a result, they aren't even visible | |
7032 | * under any other configuration. | |
7033 | */ | |
7034 | ||
7035 | /** | |
7036 | * curr_task - return the current task for a given cpu. | |
7037 | * @cpu: the processor in question. | |
7038 | * | |
7039 | * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! | |
7040 | */ | |
36c8b586 | 7041 | struct task_struct *curr_task(int cpu) |
1df5c10a LT |
7042 | { |
7043 | return cpu_curr(cpu); | |
7044 | } | |
7045 | ||
7046 | /** | |
7047 | * set_curr_task - set the current task for a given cpu. | |
7048 | * @cpu: the processor in question. | |
7049 | * @p: the task pointer to set. | |
7050 | * | |
7051 | * Description: This function must only be used when non-maskable interrupts | |
41a2d6cf IM |
7052 | * are serviced on a separate stack. It allows the architecture to switch the |
7053 | * notion of the current task on a cpu in a non-blocking manner. This function | |
1df5c10a LT |
7054 | * must be called with all CPU's synchronized, and interrupts disabled, the |
7055 | * and caller must save the original value of the current task (see | |
7056 | * curr_task() above) and restore that value before reenabling interrupts and | |
7057 | * re-starting the system. | |
7058 | * | |
7059 | * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! | |
7060 | */ | |
36c8b586 | 7061 | void set_curr_task(int cpu, struct task_struct *p) |
1df5c10a LT |
7062 | { |
7063 | cpu_curr(cpu) = p; | |
7064 | } | |
7065 | ||
7066 | #endif | |
29f59db3 SV |
7067 | |
7068 | #ifdef CONFIG_FAIR_GROUP_SCHED | |
7069 | ||
6b2d7700 SV |
7070 | #ifdef CONFIG_SMP |
7071 | /* | |
7072 | * distribute shares of all task groups among their schedulable entities, | |
7073 | * to reflect load distrbution across cpus. | |
7074 | */ | |
7075 | static int rebalance_shares(struct sched_domain *sd, int this_cpu) | |
7076 | { | |
7077 | struct cfs_rq *cfs_rq; | |
7078 | struct rq *rq = cpu_rq(this_cpu); | |
7079 | cpumask_t sdspan = sd->span; | |
7080 | int balanced = 1; | |
7081 | ||
7082 | /* Walk thr' all the task groups that we have */ | |
7083 | for_each_leaf_cfs_rq(rq, cfs_rq) { | |
7084 | int i; | |
7085 | unsigned long total_load = 0, total_shares; | |
7086 | struct task_group *tg = cfs_rq->tg; | |
7087 | ||
7088 | /* Gather total task load of this group across cpus */ | |
7089 | for_each_cpu_mask(i, sdspan) | |
7090 | total_load += tg->cfs_rq[i]->load.weight; | |
7091 | ||
7092 | /* Nothing to do if this group has no load */ | |
7093 | if (!total_load) | |
7094 | continue; | |
7095 | ||
7096 | /* | |
7097 | * tg->shares represents the number of cpu shares the task group | |
7098 | * is eligible to hold on a single cpu. On N cpus, it is | |
7099 | * eligible to hold (N * tg->shares) number of cpu shares. | |
7100 | */ | |
7101 | total_shares = tg->shares * cpus_weight(sdspan); | |
7102 | ||
7103 | /* | |
7104 | * redistribute total_shares across cpus as per the task load | |
7105 | * distribution. | |
7106 | */ | |
7107 | for_each_cpu_mask(i, sdspan) { | |
7108 | unsigned long local_load, local_shares; | |
7109 | ||
7110 | local_load = tg->cfs_rq[i]->load.weight; | |
7111 | local_shares = (local_load * total_shares) / total_load; | |
7112 | if (!local_shares) | |
7113 | local_shares = MIN_GROUP_SHARES; | |
7114 | if (local_shares == tg->se[i]->load.weight) | |
7115 | continue; | |
7116 | ||
7117 | spin_lock_irq(&cpu_rq(i)->lock); | |
7118 | set_se_shares(tg->se[i], local_shares); | |
7119 | spin_unlock_irq(&cpu_rq(i)->lock); | |
7120 | balanced = 0; | |
7121 | } | |
7122 | } | |
7123 | ||
7124 | return balanced; | |
7125 | } | |
7126 | ||
7127 | /* | |
7128 | * How frequently should we rebalance_shares() across cpus? | |
7129 | * | |
7130 | * The more frequently we rebalance shares, the more accurate is the fairness | |
7131 | * of cpu bandwidth distribution between task groups. However higher frequency | |
7132 | * also implies increased scheduling overhead. | |
7133 | * | |
7134 | * sysctl_sched_min_bal_int_shares represents the minimum interval between | |
7135 | * consecutive calls to rebalance_shares() in the same sched domain. | |
7136 | * | |
7137 | * sysctl_sched_max_bal_int_shares represents the maximum interval between | |
7138 | * consecutive calls to rebalance_shares() in the same sched domain. | |
7139 | * | |
7140 | * These settings allows for the appropriate tradeoff between accuracy of | |
7141 | * fairness and the associated overhead. | |
7142 | * | |
7143 | */ | |
7144 | ||
7145 | /* default: 8ms, units: milliseconds */ | |
7146 | const_debug unsigned int sysctl_sched_min_bal_int_shares = 8; | |
7147 | ||
7148 | /* default: 128ms, units: milliseconds */ | |
7149 | const_debug unsigned int sysctl_sched_max_bal_int_shares = 128; | |
7150 | ||
7151 | /* kernel thread that runs rebalance_shares() periodically */ | |
7152 | static int load_balance_monitor(void *unused) | |
7153 | { | |
7154 | unsigned int timeout = sysctl_sched_min_bal_int_shares; | |
7155 | struct sched_param schedparm; | |
7156 | int ret; | |
7157 | ||
7158 | /* | |
7159 | * We don't want this thread's execution to be limited by the shares | |
7160 | * assigned to default group (init_task_group). Hence make it run | |
7161 | * as a SCHED_RR RT task at the lowest priority. | |
7162 | */ | |
7163 | schedparm.sched_priority = 1; | |
7164 | ret = sched_setscheduler(current, SCHED_RR, &schedparm); | |
7165 | if (ret) | |
7166 | printk(KERN_ERR "Couldn't set SCHED_RR policy for load balance" | |
7167 | " monitor thread (error = %d) \n", ret); | |
7168 | ||
7169 | while (!kthread_should_stop()) { | |
7170 | int i, cpu, balanced = 1; | |
7171 | ||
7172 | /* Prevent cpus going down or coming up */ | |
86ef5c9a | 7173 | get_online_cpus(); |
6b2d7700 SV |
7174 | /* lockout changes to doms_cur[] array */ |
7175 | lock_doms_cur(); | |
7176 | /* | |
7177 | * Enter a rcu read-side critical section to safely walk rq->sd | |
7178 | * chain on various cpus and to walk task group list | |
7179 | * (rq->leaf_cfs_rq_list) in rebalance_shares(). | |
7180 | */ | |
7181 | rcu_read_lock(); | |
7182 | ||
7183 | for (i = 0; i < ndoms_cur; i++) { | |
7184 | cpumask_t cpumap = doms_cur[i]; | |
7185 | struct sched_domain *sd = NULL, *sd_prev = NULL; | |
7186 | ||
7187 | cpu = first_cpu(cpumap); | |
7188 | ||
7189 | /* Find the highest domain at which to balance shares */ | |
7190 | for_each_domain(cpu, sd) { | |
7191 | if (!(sd->flags & SD_LOAD_BALANCE)) | |
7192 | continue; | |
7193 | sd_prev = sd; | |
7194 | } | |
7195 | ||
7196 | sd = sd_prev; | |
7197 | /* sd == NULL? No load balance reqd in this domain */ | |
7198 | if (!sd) | |
7199 | continue; | |
7200 | ||
7201 | balanced &= rebalance_shares(sd, cpu); | |
7202 | } | |
7203 | ||
7204 | rcu_read_unlock(); | |
7205 | ||
7206 | unlock_doms_cur(); | |
86ef5c9a | 7207 | put_online_cpus(); |
6b2d7700 SV |
7208 | |
7209 | if (!balanced) | |
7210 | timeout = sysctl_sched_min_bal_int_shares; | |
7211 | else if (timeout < sysctl_sched_max_bal_int_shares) | |
7212 | timeout *= 2; | |
7213 | ||
7214 | msleep_interruptible(timeout); | |
7215 | } | |
7216 | ||
7217 | return 0; | |
7218 | } | |
7219 | #endif /* CONFIG_SMP */ | |
7220 | ||
29f59db3 | 7221 | /* allocate runqueue etc for a new task group */ |
4cf86d77 | 7222 | struct task_group *sched_create_group(void) |
29f59db3 | 7223 | { |
4cf86d77 | 7224 | struct task_group *tg; |
29f59db3 SV |
7225 | struct cfs_rq *cfs_rq; |
7226 | struct sched_entity *se; | |
9b5b7751 | 7227 | struct rq *rq; |
29f59db3 SV |
7228 | int i; |
7229 | ||
29f59db3 SV |
7230 | tg = kzalloc(sizeof(*tg), GFP_KERNEL); |
7231 | if (!tg) | |
7232 | return ERR_PTR(-ENOMEM); | |
7233 | ||
9b5b7751 | 7234 | tg->cfs_rq = kzalloc(sizeof(cfs_rq) * NR_CPUS, GFP_KERNEL); |
29f59db3 SV |
7235 | if (!tg->cfs_rq) |
7236 | goto err; | |
9b5b7751 | 7237 | tg->se = kzalloc(sizeof(se) * NR_CPUS, GFP_KERNEL); |
29f59db3 SV |
7238 | if (!tg->se) |
7239 | goto err; | |
7240 | ||
7241 | for_each_possible_cpu(i) { | |
9b5b7751 | 7242 | rq = cpu_rq(i); |
29f59db3 SV |
7243 | |
7244 | cfs_rq = kmalloc_node(sizeof(struct cfs_rq), GFP_KERNEL, | |
7245 | cpu_to_node(i)); | |
7246 | if (!cfs_rq) | |
7247 | goto err; | |
7248 | ||
7249 | se = kmalloc_node(sizeof(struct sched_entity), GFP_KERNEL, | |
7250 | cpu_to_node(i)); | |
7251 | if (!se) | |
7252 | goto err; | |
7253 | ||
7254 | memset(cfs_rq, 0, sizeof(struct cfs_rq)); | |
7255 | memset(se, 0, sizeof(struct sched_entity)); | |
7256 | ||
7257 | tg->cfs_rq[i] = cfs_rq; | |
7258 | init_cfs_rq(cfs_rq, rq); | |
7259 | cfs_rq->tg = tg; | |
29f59db3 SV |
7260 | |
7261 | tg->se[i] = se; | |
7262 | se->cfs_rq = &rq->cfs; | |
7263 | se->my_q = cfs_rq; | |
7264 | se->load.weight = NICE_0_LOAD; | |
7265 | se->load.inv_weight = div64_64(1ULL<<32, NICE_0_LOAD); | |
7266 | se->parent = NULL; | |
7267 | } | |
7268 | ||
ec2c507f SV |
7269 | tg->shares = NICE_0_LOAD; |
7270 | ||
7271 | lock_task_group_list(); | |
9b5b7751 SV |
7272 | for_each_possible_cpu(i) { |
7273 | rq = cpu_rq(i); | |
7274 | cfs_rq = tg->cfs_rq[i]; | |
7275 | list_add_rcu(&cfs_rq->leaf_cfs_rq_list, &rq->leaf_cfs_rq_list); | |
7276 | } | |
ec2c507f | 7277 | unlock_task_group_list(); |
29f59db3 | 7278 | |
9b5b7751 | 7279 | return tg; |
29f59db3 SV |
7280 | |
7281 | err: | |
7282 | for_each_possible_cpu(i) { | |
a65914b3 | 7283 | if (tg->cfs_rq) |
29f59db3 | 7284 | kfree(tg->cfs_rq[i]); |
a65914b3 | 7285 | if (tg->se) |
29f59db3 SV |
7286 | kfree(tg->se[i]); |
7287 | } | |
a65914b3 IM |
7288 | kfree(tg->cfs_rq); |
7289 | kfree(tg->se); | |
7290 | kfree(tg); | |
29f59db3 SV |
7291 | |
7292 | return ERR_PTR(-ENOMEM); | |
7293 | } | |
7294 | ||
9b5b7751 SV |
7295 | /* rcu callback to free various structures associated with a task group */ |
7296 | static void free_sched_group(struct rcu_head *rhp) | |
29f59db3 | 7297 | { |
ae8393e5 SV |
7298 | struct task_group *tg = container_of(rhp, struct task_group, rcu); |
7299 | struct cfs_rq *cfs_rq; | |
29f59db3 SV |
7300 | struct sched_entity *se; |
7301 | int i; | |
7302 | ||
29f59db3 SV |
7303 | /* now it should be safe to free those cfs_rqs */ |
7304 | for_each_possible_cpu(i) { | |
7305 | cfs_rq = tg->cfs_rq[i]; | |
7306 | kfree(cfs_rq); | |
7307 | ||
7308 | se = tg->se[i]; | |
7309 | kfree(se); | |
7310 | } | |
7311 | ||
7312 | kfree(tg->cfs_rq); | |
7313 | kfree(tg->se); | |
7314 | kfree(tg); | |
7315 | } | |
7316 | ||
9b5b7751 | 7317 | /* Destroy runqueue etc associated with a task group */ |
4cf86d77 | 7318 | void sched_destroy_group(struct task_group *tg) |
29f59db3 | 7319 | { |
7bae49d4 | 7320 | struct cfs_rq *cfs_rq = NULL; |
9b5b7751 | 7321 | int i; |
29f59db3 | 7322 | |
ec2c507f | 7323 | lock_task_group_list(); |
9b5b7751 SV |
7324 | for_each_possible_cpu(i) { |
7325 | cfs_rq = tg->cfs_rq[i]; | |
7326 | list_del_rcu(&cfs_rq->leaf_cfs_rq_list); | |
7327 | } | |
ec2c507f | 7328 | unlock_task_group_list(); |
9b5b7751 | 7329 | |
7bae49d4 | 7330 | BUG_ON(!cfs_rq); |
9b5b7751 SV |
7331 | |
7332 | /* wait for possible concurrent references to cfs_rqs complete */ | |
ae8393e5 | 7333 | call_rcu(&tg->rcu, free_sched_group); |
29f59db3 SV |
7334 | } |
7335 | ||
9b5b7751 | 7336 | /* change task's runqueue when it moves between groups. |
3a252015 IM |
7337 | * The caller of this function should have put the task in its new group |
7338 | * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to | |
7339 | * reflect its new group. | |
9b5b7751 SV |
7340 | */ |
7341 | void sched_move_task(struct task_struct *tsk) | |
29f59db3 SV |
7342 | { |
7343 | int on_rq, running; | |
7344 | unsigned long flags; | |
7345 | struct rq *rq; | |
7346 | ||
7347 | rq = task_rq_lock(tsk, &flags); | |
7348 | ||
dae51f56 | 7349 | if (tsk->sched_class != &fair_sched_class) { |
ce96b5ac | 7350 | set_task_cfs_rq(tsk, task_cpu(tsk)); |
29f59db3 | 7351 | goto done; |
dae51f56 | 7352 | } |
29f59db3 SV |
7353 | |
7354 | update_rq_clock(rq); | |
7355 | ||
051a1d1a | 7356 | running = task_current(rq, tsk); |
29f59db3 SV |
7357 | on_rq = tsk->se.on_rq; |
7358 | ||
83b699ed | 7359 | if (on_rq) { |
29f59db3 | 7360 | dequeue_task(rq, tsk, 0); |
83b699ed SV |
7361 | if (unlikely(running)) |
7362 | tsk->sched_class->put_prev_task(rq, tsk); | |
7363 | } | |
29f59db3 | 7364 | |
ce96b5ac | 7365 | set_task_cfs_rq(tsk, task_cpu(tsk)); |
29f59db3 | 7366 | |
83b699ed SV |
7367 | if (on_rq) { |
7368 | if (unlikely(running)) | |
7369 | tsk->sched_class->set_curr_task(rq); | |
7074badb | 7370 | enqueue_task(rq, tsk, 0); |
83b699ed | 7371 | } |
29f59db3 SV |
7372 | |
7373 | done: | |
7374 | task_rq_unlock(rq, &flags); | |
7375 | } | |
7376 | ||
6b2d7700 | 7377 | /* rq->lock to be locked by caller */ |
29f59db3 SV |
7378 | static void set_se_shares(struct sched_entity *se, unsigned long shares) |
7379 | { | |
7380 | struct cfs_rq *cfs_rq = se->cfs_rq; | |
7381 | struct rq *rq = cfs_rq->rq; | |
7382 | int on_rq; | |
7383 | ||
6b2d7700 SV |
7384 | if (!shares) |
7385 | shares = MIN_GROUP_SHARES; | |
29f59db3 SV |
7386 | |
7387 | on_rq = se->on_rq; | |
6b2d7700 | 7388 | if (on_rq) { |
29f59db3 | 7389 | dequeue_entity(cfs_rq, se, 0); |
6b2d7700 SV |
7390 | dec_cpu_load(rq, se->load.weight); |
7391 | } | |
29f59db3 SV |
7392 | |
7393 | se->load.weight = shares; | |
7394 | se->load.inv_weight = div64_64((1ULL<<32), shares); | |
7395 | ||
6b2d7700 | 7396 | if (on_rq) { |
29f59db3 | 7397 | enqueue_entity(cfs_rq, se, 0); |
6b2d7700 SV |
7398 | inc_cpu_load(rq, se->load.weight); |
7399 | } | |
29f59db3 SV |
7400 | } |
7401 | ||
4cf86d77 | 7402 | int sched_group_set_shares(struct task_group *tg, unsigned long shares) |
29f59db3 SV |
7403 | { |
7404 | int i; | |
6b2d7700 SV |
7405 | struct cfs_rq *cfs_rq; |
7406 | struct rq *rq; | |
c61935fd | 7407 | |
ec2c507f | 7408 | lock_task_group_list(); |
9b5b7751 | 7409 | if (tg->shares == shares) |
5cb350ba | 7410 | goto done; |
29f59db3 | 7411 | |
6b2d7700 SV |
7412 | if (shares < MIN_GROUP_SHARES) |
7413 | shares = MIN_GROUP_SHARES; | |
7414 | ||
7415 | /* | |
7416 | * Prevent any load balance activity (rebalance_shares, | |
7417 | * load_balance_fair) from referring to this group first, | |
7418 | * by taking it off the rq->leaf_cfs_rq_list on each cpu. | |
7419 | */ | |
7420 | for_each_possible_cpu(i) { | |
7421 | cfs_rq = tg->cfs_rq[i]; | |
7422 | list_del_rcu(&cfs_rq->leaf_cfs_rq_list); | |
7423 | } | |
7424 | ||
7425 | /* wait for any ongoing reference to this group to finish */ | |
7426 | synchronize_sched(); | |
7427 | ||
7428 | /* | |
7429 | * Now we are free to modify the group's share on each cpu | |
7430 | * w/o tripping rebalance_share or load_balance_fair. | |
7431 | */ | |
9b5b7751 | 7432 | tg->shares = shares; |
6b2d7700 SV |
7433 | for_each_possible_cpu(i) { |
7434 | spin_lock_irq(&cpu_rq(i)->lock); | |
9b5b7751 | 7435 | set_se_shares(tg->se[i], shares); |
6b2d7700 SV |
7436 | spin_unlock_irq(&cpu_rq(i)->lock); |
7437 | } | |
29f59db3 | 7438 | |
6b2d7700 SV |
7439 | /* |
7440 | * Enable load balance activity on this group, by inserting it back on | |
7441 | * each cpu's rq->leaf_cfs_rq_list. | |
7442 | */ | |
7443 | for_each_possible_cpu(i) { | |
7444 | rq = cpu_rq(i); | |
7445 | cfs_rq = tg->cfs_rq[i]; | |
7446 | list_add_rcu(&cfs_rq->leaf_cfs_rq_list, &rq->leaf_cfs_rq_list); | |
7447 | } | |
5cb350ba | 7448 | done: |
ec2c507f | 7449 | unlock_task_group_list(); |
9b5b7751 | 7450 | return 0; |
29f59db3 SV |
7451 | } |
7452 | ||
5cb350ba DG |
7453 | unsigned long sched_group_shares(struct task_group *tg) |
7454 | { | |
7455 | return tg->shares; | |
7456 | } | |
7457 | ||
3a252015 | 7458 | #endif /* CONFIG_FAIR_GROUP_SCHED */ |
68318b8e SV |
7459 | |
7460 | #ifdef CONFIG_FAIR_CGROUP_SCHED | |
7461 | ||
7462 | /* return corresponding task_group object of a cgroup */ | |
2b01dfe3 | 7463 | static inline struct task_group *cgroup_tg(struct cgroup *cgrp) |
68318b8e | 7464 | { |
2b01dfe3 PM |
7465 | return container_of(cgroup_subsys_state(cgrp, cpu_cgroup_subsys_id), |
7466 | struct task_group, css); | |
68318b8e SV |
7467 | } |
7468 | ||
7469 | static struct cgroup_subsys_state * | |
2b01dfe3 | 7470 | cpu_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cgrp) |
68318b8e SV |
7471 | { |
7472 | struct task_group *tg; | |
7473 | ||
2b01dfe3 | 7474 | if (!cgrp->parent) { |
68318b8e | 7475 | /* This is early initialization for the top cgroup */ |
2b01dfe3 | 7476 | init_task_group.css.cgroup = cgrp; |
68318b8e SV |
7477 | return &init_task_group.css; |
7478 | } | |
7479 | ||
7480 | /* we support only 1-level deep hierarchical scheduler atm */ | |
2b01dfe3 | 7481 | if (cgrp->parent->parent) |
68318b8e SV |
7482 | return ERR_PTR(-EINVAL); |
7483 | ||
7484 | tg = sched_create_group(); | |
7485 | if (IS_ERR(tg)) | |
7486 | return ERR_PTR(-ENOMEM); | |
7487 | ||
7488 | /* Bind the cgroup to task_group object we just created */ | |
2b01dfe3 | 7489 | tg->css.cgroup = cgrp; |
68318b8e SV |
7490 | |
7491 | return &tg->css; | |
7492 | } | |
7493 | ||
41a2d6cf IM |
7494 | static void |
7495 | cpu_cgroup_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp) | |
68318b8e | 7496 | { |
2b01dfe3 | 7497 | struct task_group *tg = cgroup_tg(cgrp); |
68318b8e SV |
7498 | |
7499 | sched_destroy_group(tg); | |
7500 | } | |
7501 | ||
41a2d6cf IM |
7502 | static int |
7503 | cpu_cgroup_can_attach(struct cgroup_subsys *ss, struct cgroup *cgrp, | |
7504 | struct task_struct *tsk) | |
68318b8e SV |
7505 | { |
7506 | /* We don't support RT-tasks being in separate groups */ | |
7507 | if (tsk->sched_class != &fair_sched_class) | |
7508 | return -EINVAL; | |
7509 | ||
7510 | return 0; | |
7511 | } | |
7512 | ||
7513 | static void | |
2b01dfe3 | 7514 | cpu_cgroup_attach(struct cgroup_subsys *ss, struct cgroup *cgrp, |
68318b8e SV |
7515 | struct cgroup *old_cont, struct task_struct *tsk) |
7516 | { | |
7517 | sched_move_task(tsk); | |
7518 | } | |
7519 | ||
2b01dfe3 PM |
7520 | static int cpu_shares_write_uint(struct cgroup *cgrp, struct cftype *cftype, |
7521 | u64 shareval) | |
68318b8e | 7522 | { |
2b01dfe3 | 7523 | return sched_group_set_shares(cgroup_tg(cgrp), shareval); |
68318b8e SV |
7524 | } |
7525 | ||
2b01dfe3 | 7526 | static u64 cpu_shares_read_uint(struct cgroup *cgrp, struct cftype *cft) |
68318b8e | 7527 | { |
2b01dfe3 | 7528 | struct task_group *tg = cgroup_tg(cgrp); |
68318b8e SV |
7529 | |
7530 | return (u64) tg->shares; | |
7531 | } | |
7532 | ||
fe5c7cc2 PM |
7533 | static struct cftype cpu_files[] = { |
7534 | { | |
7535 | .name = "shares", | |
7536 | .read_uint = cpu_shares_read_uint, | |
7537 | .write_uint = cpu_shares_write_uint, | |
7538 | }, | |
68318b8e SV |
7539 | }; |
7540 | ||
7541 | static int cpu_cgroup_populate(struct cgroup_subsys *ss, struct cgroup *cont) | |
7542 | { | |
fe5c7cc2 | 7543 | return cgroup_add_files(cont, ss, cpu_files, ARRAY_SIZE(cpu_files)); |
68318b8e SV |
7544 | } |
7545 | ||
7546 | struct cgroup_subsys cpu_cgroup_subsys = { | |
38605cae IM |
7547 | .name = "cpu", |
7548 | .create = cpu_cgroup_create, | |
7549 | .destroy = cpu_cgroup_destroy, | |
7550 | .can_attach = cpu_cgroup_can_attach, | |
7551 | .attach = cpu_cgroup_attach, | |
7552 | .populate = cpu_cgroup_populate, | |
7553 | .subsys_id = cpu_cgroup_subsys_id, | |
68318b8e SV |
7554 | .early_init = 1, |
7555 | }; | |
7556 | ||
7557 | #endif /* CONFIG_FAIR_CGROUP_SCHED */ | |
d842de87 SV |
7558 | |
7559 | #ifdef CONFIG_CGROUP_CPUACCT | |
7560 | ||
7561 | /* | |
7562 | * CPU accounting code for task groups. | |
7563 | * | |
7564 | * Based on the work by Paul Menage (menage@google.com) and Balbir Singh | |
7565 | * (balbir@in.ibm.com). | |
7566 | */ | |
7567 | ||
7568 | /* track cpu usage of a group of tasks */ | |
7569 | struct cpuacct { | |
7570 | struct cgroup_subsys_state css; | |
7571 | /* cpuusage holds pointer to a u64-type object on every cpu */ | |
7572 | u64 *cpuusage; | |
7573 | }; | |
7574 | ||
7575 | struct cgroup_subsys cpuacct_subsys; | |
7576 | ||
7577 | /* return cpu accounting group corresponding to this container */ | |
7578 | static inline struct cpuacct *cgroup_ca(struct cgroup *cont) | |
7579 | { | |
7580 | return container_of(cgroup_subsys_state(cont, cpuacct_subsys_id), | |
7581 | struct cpuacct, css); | |
7582 | } | |
7583 | ||
7584 | /* return cpu accounting group to which this task belongs */ | |
7585 | static inline struct cpuacct *task_ca(struct task_struct *tsk) | |
7586 | { | |
7587 | return container_of(task_subsys_state(tsk, cpuacct_subsys_id), | |
7588 | struct cpuacct, css); | |
7589 | } | |
7590 | ||
7591 | /* create a new cpu accounting group */ | |
7592 | static struct cgroup_subsys_state *cpuacct_create( | |
7593 | struct cgroup_subsys *ss, struct cgroup *cont) | |
7594 | { | |
7595 | struct cpuacct *ca = kzalloc(sizeof(*ca), GFP_KERNEL); | |
7596 | ||
7597 | if (!ca) | |
7598 | return ERR_PTR(-ENOMEM); | |
7599 | ||
7600 | ca->cpuusage = alloc_percpu(u64); | |
7601 | if (!ca->cpuusage) { | |
7602 | kfree(ca); | |
7603 | return ERR_PTR(-ENOMEM); | |
7604 | } | |
7605 | ||
7606 | return &ca->css; | |
7607 | } | |
7608 | ||
7609 | /* destroy an existing cpu accounting group */ | |
41a2d6cf IM |
7610 | static void |
7611 | cpuacct_destroy(struct cgroup_subsys *ss, struct cgroup *cont) | |
d842de87 SV |
7612 | { |
7613 | struct cpuacct *ca = cgroup_ca(cont); | |
7614 | ||
7615 | free_percpu(ca->cpuusage); | |
7616 | kfree(ca); | |
7617 | } | |
7618 | ||
7619 | /* return total cpu usage (in nanoseconds) of a group */ | |
7620 | static u64 cpuusage_read(struct cgroup *cont, struct cftype *cft) | |
7621 | { | |
7622 | struct cpuacct *ca = cgroup_ca(cont); | |
7623 | u64 totalcpuusage = 0; | |
7624 | int i; | |
7625 | ||
7626 | for_each_possible_cpu(i) { | |
7627 | u64 *cpuusage = percpu_ptr(ca->cpuusage, i); | |
7628 | ||
7629 | /* | |
7630 | * Take rq->lock to make 64-bit addition safe on 32-bit | |
7631 | * platforms. | |
7632 | */ | |
7633 | spin_lock_irq(&cpu_rq(i)->lock); | |
7634 | totalcpuusage += *cpuusage; | |
7635 | spin_unlock_irq(&cpu_rq(i)->lock); | |
7636 | } | |
7637 | ||
7638 | return totalcpuusage; | |
7639 | } | |
7640 | ||
7641 | static struct cftype files[] = { | |
7642 | { | |
7643 | .name = "usage", | |
7644 | .read_uint = cpuusage_read, | |
7645 | }, | |
7646 | }; | |
7647 | ||
7648 | static int cpuacct_populate(struct cgroup_subsys *ss, struct cgroup *cont) | |
7649 | { | |
7650 | return cgroup_add_files(cont, ss, files, ARRAY_SIZE(files)); | |
7651 | } | |
7652 | ||
7653 | /* | |
7654 | * charge this task's execution time to its accounting group. | |
7655 | * | |
7656 | * called with rq->lock held. | |
7657 | */ | |
7658 | static void cpuacct_charge(struct task_struct *tsk, u64 cputime) | |
7659 | { | |
7660 | struct cpuacct *ca; | |
7661 | ||
7662 | if (!cpuacct_subsys.active) | |
7663 | return; | |
7664 | ||
7665 | ca = task_ca(tsk); | |
7666 | if (ca) { | |
7667 | u64 *cpuusage = percpu_ptr(ca->cpuusage, task_cpu(tsk)); | |
7668 | ||
7669 | *cpuusage += cputime; | |
7670 | } | |
7671 | } | |
7672 | ||
7673 | struct cgroup_subsys cpuacct_subsys = { | |
7674 | .name = "cpuacct", | |
7675 | .create = cpuacct_create, | |
7676 | .destroy = cpuacct_destroy, | |
7677 | .populate = cpuacct_populate, | |
7678 | .subsys_id = cpuacct_subsys_id, | |
7679 | }; | |
7680 | #endif /* CONFIG_CGROUP_CPUACCT */ |