Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * kernel/sched.c | |
3 | * | |
4 | * Kernel scheduler and related syscalls | |
5 | * | |
6 | * Copyright (C) 1991-2002 Linus Torvalds | |
7 | * | |
8 | * 1996-12-23 Modified by Dave Grothe to fix bugs in semaphores and | |
9 | * make semaphores SMP safe | |
10 | * 1998-11-19 Implemented schedule_timeout() and related stuff | |
11 | * by Andrea Arcangeli | |
12 | * 2002-01-04 New ultra-scalable O(1) scheduler by Ingo Molnar: | |
13 | * hybrid priority-list and round-robin design with | |
14 | * an array-switch method of distributing timeslices | |
15 | * and per-CPU runqueues. Cleanups and useful suggestions | |
16 | * by Davide Libenzi, preemptible kernel bits by Robert Love. | |
17 | * 2003-09-03 Interactivity tuning by Con Kolivas. | |
18 | * 2004-04-02 Scheduler domains code by Nick Piggin | |
c31f2e8a IM |
19 | * 2007-04-15 Work begun on replacing all interactivity tuning with a |
20 | * fair scheduling design by Con Kolivas. | |
21 | * 2007-05-05 Load balancing (smp-nice) and other improvements | |
22 | * by Peter Williams | |
23 | * 2007-05-06 Interactivity improvements to CFS by Mike Galbraith | |
24 | * 2007-07-01 Group scheduling enhancements by Srivatsa Vaddagiri | |
1da177e4 LT |
25 | */ |
26 | ||
27 | #include <linux/mm.h> | |
28 | #include <linux/module.h> | |
29 | #include <linux/nmi.h> | |
30 | #include <linux/init.h> | |
dff06c15 | 31 | #include <linux/uaccess.h> |
1da177e4 LT |
32 | #include <linux/highmem.h> |
33 | #include <linux/smp_lock.h> | |
34 | #include <asm/mmu_context.h> | |
35 | #include <linux/interrupt.h> | |
c59ede7b | 36 | #include <linux/capability.h> |
1da177e4 LT |
37 | #include <linux/completion.h> |
38 | #include <linux/kernel_stat.h> | |
9a11b49a | 39 | #include <linux/debug_locks.h> |
1da177e4 LT |
40 | #include <linux/security.h> |
41 | #include <linux/notifier.h> | |
42 | #include <linux/profile.h> | |
7dfb7103 | 43 | #include <linux/freezer.h> |
198e2f18 | 44 | #include <linux/vmalloc.h> |
1da177e4 LT |
45 | #include <linux/blkdev.h> |
46 | #include <linux/delay.h> | |
47 | #include <linux/smp.h> | |
48 | #include <linux/threads.h> | |
49 | #include <linux/timer.h> | |
50 | #include <linux/rcupdate.h> | |
51 | #include <linux/cpu.h> | |
52 | #include <linux/cpuset.h> | |
53 | #include <linux/percpu.h> | |
54 | #include <linux/kthread.h> | |
55 | #include <linux/seq_file.h> | |
e692ab53 | 56 | #include <linux/sysctl.h> |
1da177e4 LT |
57 | #include <linux/syscalls.h> |
58 | #include <linux/times.h> | |
8f0ab514 | 59 | #include <linux/tsacct_kern.h> |
c6fd91f0 | 60 | #include <linux/kprobes.h> |
0ff92245 | 61 | #include <linux/delayacct.h> |
5517d86b | 62 | #include <linux/reciprocal_div.h> |
dff06c15 | 63 | #include <linux/unistd.h> |
f5ff8422 | 64 | #include <linux/pagemap.h> |
1da177e4 | 65 | |
5517d86b | 66 | #include <asm/tlb.h> |
1da177e4 | 67 | |
b035b6de AD |
68 | /* |
69 | * Scheduler clock - returns current time in nanosec units. | |
70 | * This is default implementation. | |
71 | * Architectures and sub-architectures can override this. | |
72 | */ | |
73 | unsigned long long __attribute__((weak)) sched_clock(void) | |
74 | { | |
75 | return (unsigned long long)jiffies * (1000000000 / HZ); | |
76 | } | |
77 | ||
3a5e4dc1 AK |
78 | #ifdef CONFIG_SMP |
79 | #define is_migration_thread(p, rq) ((p) == (rq)->migration_thread) | |
80 | #else | |
81 | #define is_migration_thread(p, rq) 0 | |
82 | #endif | |
83 | ||
1da177e4 LT |
84 | /* |
85 | * Convert user-nice values [ -20 ... 0 ... 19 ] | |
86 | * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ], | |
87 | * and back. | |
88 | */ | |
89 | #define NICE_TO_PRIO(nice) (MAX_RT_PRIO + (nice) + 20) | |
90 | #define PRIO_TO_NICE(prio) ((prio) - MAX_RT_PRIO - 20) | |
91 | #define TASK_NICE(p) PRIO_TO_NICE((p)->static_prio) | |
92 | ||
93 | /* | |
94 | * 'User priority' is the nice value converted to something we | |
95 | * can work with better when scaling various scheduler parameters, | |
96 | * it's a [ 0 ... 39 ] range. | |
97 | */ | |
98 | #define USER_PRIO(p) ((p)-MAX_RT_PRIO) | |
99 | #define TASK_USER_PRIO(p) USER_PRIO((p)->static_prio) | |
100 | #define MAX_USER_PRIO (USER_PRIO(MAX_PRIO)) | |
101 | ||
102 | /* | |
103 | * Some helpers for converting nanosecond timing to jiffy resolution | |
104 | */ | |
a4ec24b4 | 105 | #define NS_TO_JIFFIES(TIME) ((unsigned long)(TIME) / (1000000000 / HZ)) |
1da177e4 LT |
106 | #define JIFFIES_TO_NS(TIME) ((TIME) * (1000000000 / HZ)) |
107 | ||
6aa645ea IM |
108 | #define NICE_0_LOAD SCHED_LOAD_SCALE |
109 | #define NICE_0_SHIFT SCHED_LOAD_SHIFT | |
110 | ||
1da177e4 LT |
111 | /* |
112 | * These are the 'tuning knobs' of the scheduler: | |
113 | * | |
a4ec24b4 | 114 | * default timeslice is 100 msecs (used only for SCHED_RR tasks). |
1da177e4 LT |
115 | * Timeslices get refilled after they expire. |
116 | */ | |
1da177e4 | 117 | #define DEF_TIMESLICE (100 * HZ / 1000) |
2dd73a4f | 118 | |
5517d86b ED |
119 | #ifdef CONFIG_SMP |
120 | /* | |
121 | * Divide a load by a sched group cpu_power : (load / sg->__cpu_power) | |
122 | * Since cpu_power is a 'constant', we can use a reciprocal divide. | |
123 | */ | |
124 | static inline u32 sg_div_cpu_power(const struct sched_group *sg, u32 load) | |
125 | { | |
126 | return reciprocal_divide(load, sg->reciprocal_cpu_power); | |
127 | } | |
128 | ||
129 | /* | |
130 | * Each time a sched group cpu_power is changed, | |
131 | * we must compute its reciprocal value | |
132 | */ | |
133 | static inline void sg_inc_cpu_power(struct sched_group *sg, u32 val) | |
134 | { | |
135 | sg->__cpu_power += val; | |
136 | sg->reciprocal_cpu_power = reciprocal_value(sg->__cpu_power); | |
137 | } | |
138 | #endif | |
139 | ||
e05606d3 IM |
140 | static inline int rt_policy(int policy) |
141 | { | |
142 | if (unlikely(policy == SCHED_FIFO) || unlikely(policy == SCHED_RR)) | |
143 | return 1; | |
144 | return 0; | |
145 | } | |
146 | ||
147 | static inline int task_has_rt_policy(struct task_struct *p) | |
148 | { | |
149 | return rt_policy(p->policy); | |
150 | } | |
151 | ||
1da177e4 | 152 | /* |
6aa645ea | 153 | * This is the priority-queue data structure of the RT scheduling class: |
1da177e4 | 154 | */ |
6aa645ea IM |
155 | struct rt_prio_array { |
156 | DECLARE_BITMAP(bitmap, MAX_RT_PRIO+1); /* include 1 bit for delimiter */ | |
157 | struct list_head queue[MAX_RT_PRIO]; | |
158 | }; | |
159 | ||
29f59db3 SV |
160 | #ifdef CONFIG_FAIR_GROUP_SCHED |
161 | ||
29f59db3 SV |
162 | struct cfs_rq; |
163 | ||
164 | /* task group related information */ | |
4cf86d77 | 165 | struct task_group { |
29f59db3 SV |
166 | /* schedulable entities of this group on each cpu */ |
167 | struct sched_entity **se; | |
168 | /* runqueue "owned" by this group on each cpu */ | |
169 | struct cfs_rq **cfs_rq; | |
170 | unsigned long shares; | |
5cb350ba DG |
171 | /* spinlock to serialize modification to shares */ |
172 | spinlock_t lock; | |
29f59db3 SV |
173 | }; |
174 | ||
175 | /* Default task group's sched entity on each cpu */ | |
176 | static DEFINE_PER_CPU(struct sched_entity, init_sched_entity); | |
177 | /* Default task group's cfs_rq on each cpu */ | |
178 | static DEFINE_PER_CPU(struct cfs_rq, init_cfs_rq) ____cacheline_aligned_in_smp; | |
179 | ||
9b5b7751 SV |
180 | static struct sched_entity *init_sched_entity_p[NR_CPUS]; |
181 | static struct cfs_rq *init_cfs_rq_p[NR_CPUS]; | |
29f59db3 SV |
182 | |
183 | /* Default task group. | |
3a252015 | 184 | * Every task in system belong to this group at bootup. |
29f59db3 | 185 | */ |
4cf86d77 | 186 | struct task_group init_task_group = { |
3a252015 IM |
187 | .se = init_sched_entity_p, |
188 | .cfs_rq = init_cfs_rq_p, | |
189 | }; | |
9b5b7751 | 190 | |
24e377a8 | 191 | #ifdef CONFIG_FAIR_USER_SCHED |
3a252015 | 192 | # define INIT_TASK_GRP_LOAD 2*NICE_0_LOAD |
24e377a8 | 193 | #else |
3a252015 | 194 | # define INIT_TASK_GRP_LOAD NICE_0_LOAD |
24e377a8 SV |
195 | #endif |
196 | ||
4cf86d77 | 197 | static int init_task_group_load = INIT_TASK_GRP_LOAD; |
29f59db3 SV |
198 | |
199 | /* return group to which a task belongs */ | |
4cf86d77 | 200 | static inline struct task_group *task_group(struct task_struct *p) |
29f59db3 | 201 | { |
4cf86d77 | 202 | struct task_group *tg; |
9b5b7751 | 203 | |
24e377a8 SV |
204 | #ifdef CONFIG_FAIR_USER_SCHED |
205 | tg = p->user->tg; | |
206 | #else | |
4cf86d77 | 207 | tg = &init_task_group; |
24e377a8 | 208 | #endif |
9b5b7751 SV |
209 | |
210 | return tg; | |
29f59db3 SV |
211 | } |
212 | ||
213 | /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */ | |
214 | static inline void set_task_cfs_rq(struct task_struct *p) | |
215 | { | |
4cf86d77 IM |
216 | p->se.cfs_rq = task_group(p)->cfs_rq[task_cpu(p)]; |
217 | p->se.parent = task_group(p)->se[task_cpu(p)]; | |
29f59db3 SV |
218 | } |
219 | ||
220 | #else | |
221 | ||
222 | static inline void set_task_cfs_rq(struct task_struct *p) { } | |
223 | ||
224 | #endif /* CONFIG_FAIR_GROUP_SCHED */ | |
225 | ||
6aa645ea IM |
226 | /* CFS-related fields in a runqueue */ |
227 | struct cfs_rq { | |
228 | struct load_weight load; | |
229 | unsigned long nr_running; | |
230 | ||
6aa645ea | 231 | u64 exec_clock; |
e9acbff6 | 232 | u64 min_vruntime; |
6aa645ea IM |
233 | |
234 | struct rb_root tasks_timeline; | |
235 | struct rb_node *rb_leftmost; | |
236 | struct rb_node *rb_load_balance_curr; | |
6aa645ea IM |
237 | /* 'curr' points to currently running entity on this cfs_rq. |
238 | * It is set to NULL otherwise (i.e when none are currently running). | |
239 | */ | |
240 | struct sched_entity *curr; | |
ddc97297 PZ |
241 | |
242 | unsigned long nr_spread_over; | |
243 | ||
62160e3f | 244 | #ifdef CONFIG_FAIR_GROUP_SCHED |
6aa645ea IM |
245 | struct rq *rq; /* cpu runqueue to which this cfs_rq is attached */ |
246 | ||
247 | /* leaf cfs_rqs are those that hold tasks (lowest schedulable entity in | |
248 | * a hierarchy). Non-leaf lrqs hold other higher schedulable entities | |
249 | * (like users, containers etc.) | |
250 | * | |
251 | * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This | |
252 | * list is used during load balance. | |
253 | */ | |
254 | struct list_head leaf_cfs_rq_list; /* Better name : task_cfs_rq_list? */ | |
4cf86d77 | 255 | struct task_group *tg; /* group that "owns" this runqueue */ |
9b5b7751 | 256 | struct rcu_head rcu; |
6aa645ea IM |
257 | #endif |
258 | }; | |
1da177e4 | 259 | |
6aa645ea IM |
260 | /* Real-Time classes' related field in a runqueue: */ |
261 | struct rt_rq { | |
262 | struct rt_prio_array active; | |
263 | int rt_load_balance_idx; | |
264 | struct list_head *rt_load_balance_head, *rt_load_balance_curr; | |
265 | }; | |
266 | ||
1da177e4 LT |
267 | /* |
268 | * This is the main, per-CPU runqueue data structure. | |
269 | * | |
270 | * Locking rule: those places that want to lock multiple runqueues | |
271 | * (such as the load balancing or the thread migration code), lock | |
272 | * acquire operations must be ordered by ascending &runqueue. | |
273 | */ | |
70b97a7f | 274 | struct rq { |
6aa645ea | 275 | spinlock_t lock; /* runqueue lock */ |
1da177e4 LT |
276 | |
277 | /* | |
278 | * nr_running and cpu_load should be in the same cacheline because | |
279 | * remote CPUs use both these fields when doing load calculation. | |
280 | */ | |
281 | unsigned long nr_running; | |
6aa645ea IM |
282 | #define CPU_LOAD_IDX_MAX 5 |
283 | unsigned long cpu_load[CPU_LOAD_IDX_MAX]; | |
bdecea3a | 284 | unsigned char idle_at_tick; |
46cb4b7c SS |
285 | #ifdef CONFIG_NO_HZ |
286 | unsigned char in_nohz_recently; | |
287 | #endif | |
495eca49 | 288 | struct load_weight load; /* capture load from *all* tasks on this cpu */ |
6aa645ea IM |
289 | unsigned long nr_load_updates; |
290 | u64 nr_switches; | |
291 | ||
292 | struct cfs_rq cfs; | |
293 | #ifdef CONFIG_FAIR_GROUP_SCHED | |
294 | struct list_head leaf_cfs_rq_list; /* list of leaf cfs_rq on this cpu */ | |
1da177e4 | 295 | #endif |
6aa645ea | 296 | struct rt_rq rt; |
1da177e4 LT |
297 | |
298 | /* | |
299 | * This is part of a global counter where only the total sum | |
300 | * over all CPUs matters. A task can increase this counter on | |
301 | * one CPU and if it got migrated afterwards it may decrease | |
302 | * it on another CPU. Always updated under the runqueue lock: | |
303 | */ | |
304 | unsigned long nr_uninterruptible; | |
305 | ||
36c8b586 | 306 | struct task_struct *curr, *idle; |
c9819f45 | 307 | unsigned long next_balance; |
1da177e4 | 308 | struct mm_struct *prev_mm; |
6aa645ea | 309 | |
6aa645ea IM |
310 | u64 clock, prev_clock_raw; |
311 | s64 clock_max_delta; | |
312 | ||
313 | unsigned int clock_warps, clock_overflows; | |
2aa44d05 IM |
314 | u64 idle_clock; |
315 | unsigned int clock_deep_idle_events; | |
529c7726 | 316 | u64 tick_timestamp; |
6aa645ea | 317 | |
1da177e4 LT |
318 | atomic_t nr_iowait; |
319 | ||
320 | #ifdef CONFIG_SMP | |
321 | struct sched_domain *sd; | |
322 | ||
323 | /* For active balancing */ | |
324 | int active_balance; | |
325 | int push_cpu; | |
0a2966b4 | 326 | int cpu; /* cpu of this runqueue */ |
1da177e4 | 327 | |
36c8b586 | 328 | struct task_struct *migration_thread; |
1da177e4 LT |
329 | struct list_head migration_queue; |
330 | #endif | |
331 | ||
332 | #ifdef CONFIG_SCHEDSTATS | |
333 | /* latency stats */ | |
334 | struct sched_info rq_sched_info; | |
335 | ||
336 | /* sys_sched_yield() stats */ | |
337 | unsigned long yld_exp_empty; | |
338 | unsigned long yld_act_empty; | |
339 | unsigned long yld_both_empty; | |
2d72376b | 340 | unsigned long yld_count; |
1da177e4 LT |
341 | |
342 | /* schedule() stats */ | |
343 | unsigned long sched_switch; | |
2d72376b | 344 | unsigned long sched_count; |
1da177e4 LT |
345 | unsigned long sched_goidle; |
346 | ||
347 | /* try_to_wake_up() stats */ | |
2d72376b | 348 | unsigned long ttwu_count; |
1da177e4 | 349 | unsigned long ttwu_local; |
b8efb561 IM |
350 | |
351 | /* BKL stats */ | |
2d72376b | 352 | unsigned long bkl_count; |
1da177e4 | 353 | #endif |
fcb99371 | 354 | struct lock_class_key rq_lock_key; |
1da177e4 LT |
355 | }; |
356 | ||
f34e3b61 | 357 | static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues); |
5be9361c | 358 | static DEFINE_MUTEX(sched_hotcpu_mutex); |
1da177e4 | 359 | |
dd41f596 IM |
360 | static inline void check_preempt_curr(struct rq *rq, struct task_struct *p) |
361 | { | |
362 | rq->curr->sched_class->check_preempt_curr(rq, p); | |
363 | } | |
364 | ||
0a2966b4 CL |
365 | static inline int cpu_of(struct rq *rq) |
366 | { | |
367 | #ifdef CONFIG_SMP | |
368 | return rq->cpu; | |
369 | #else | |
370 | return 0; | |
371 | #endif | |
372 | } | |
373 | ||
20d315d4 | 374 | /* |
b04a0f4c IM |
375 | * Update the per-runqueue clock, as finegrained as the platform can give |
376 | * us, but without assuming monotonicity, etc.: | |
20d315d4 | 377 | */ |
b04a0f4c | 378 | static void __update_rq_clock(struct rq *rq) |
20d315d4 IM |
379 | { |
380 | u64 prev_raw = rq->prev_clock_raw; | |
381 | u64 now = sched_clock(); | |
382 | s64 delta = now - prev_raw; | |
383 | u64 clock = rq->clock; | |
384 | ||
b04a0f4c IM |
385 | #ifdef CONFIG_SCHED_DEBUG |
386 | WARN_ON_ONCE(cpu_of(rq) != smp_processor_id()); | |
387 | #endif | |
20d315d4 IM |
388 | /* |
389 | * Protect against sched_clock() occasionally going backwards: | |
390 | */ | |
391 | if (unlikely(delta < 0)) { | |
392 | clock++; | |
393 | rq->clock_warps++; | |
394 | } else { | |
395 | /* | |
396 | * Catch too large forward jumps too: | |
397 | */ | |
529c7726 IM |
398 | if (unlikely(clock + delta > rq->tick_timestamp + TICK_NSEC)) { |
399 | if (clock < rq->tick_timestamp + TICK_NSEC) | |
400 | clock = rq->tick_timestamp + TICK_NSEC; | |
401 | else | |
402 | clock++; | |
20d315d4 IM |
403 | rq->clock_overflows++; |
404 | } else { | |
405 | if (unlikely(delta > rq->clock_max_delta)) | |
406 | rq->clock_max_delta = delta; | |
407 | clock += delta; | |
408 | } | |
409 | } | |
410 | ||
411 | rq->prev_clock_raw = now; | |
412 | rq->clock = clock; | |
b04a0f4c | 413 | } |
20d315d4 | 414 | |
b04a0f4c IM |
415 | static void update_rq_clock(struct rq *rq) |
416 | { | |
417 | if (likely(smp_processor_id() == cpu_of(rq))) | |
418 | __update_rq_clock(rq); | |
20d315d4 IM |
419 | } |
420 | ||
674311d5 NP |
421 | /* |
422 | * The domain tree (rq->sd) is protected by RCU's quiescent state transition. | |
1a20ff27 | 423 | * See detach_destroy_domains: synchronize_sched for details. |
674311d5 NP |
424 | * |
425 | * The domain tree of any CPU may only be accessed from within | |
426 | * preempt-disabled sections. | |
427 | */ | |
48f24c4d IM |
428 | #define for_each_domain(cpu, __sd) \ |
429 | for (__sd = rcu_dereference(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent) | |
1da177e4 LT |
430 | |
431 | #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu))) | |
432 | #define this_rq() (&__get_cpu_var(runqueues)) | |
433 | #define task_rq(p) cpu_rq(task_cpu(p)) | |
434 | #define cpu_curr(cpu) (cpu_rq(cpu)->curr) | |
435 | ||
bf5c91ba IM |
436 | /* |
437 | * Tunables that become constants when CONFIG_SCHED_DEBUG is off: | |
438 | */ | |
439 | #ifdef CONFIG_SCHED_DEBUG | |
440 | # define const_debug __read_mostly | |
441 | #else | |
442 | # define const_debug static const | |
443 | #endif | |
444 | ||
445 | /* | |
446 | * Debugging: various feature bits | |
447 | */ | |
448 | enum { | |
bbdba7c0 IM |
449 | SCHED_FEAT_NEW_FAIR_SLEEPERS = 1, |
450 | SCHED_FEAT_START_DEBIT = 2, | |
06877c33 | 451 | SCHED_FEAT_TREE_AVG = 4, |
bbdba7c0 | 452 | SCHED_FEAT_APPROX_AVG = 8, |
ce6c1311 | 453 | SCHED_FEAT_WAKEUP_PREEMPT = 16, |
95938a35 | 454 | SCHED_FEAT_PREEMPT_RESTRICT = 32, |
bf5c91ba IM |
455 | }; |
456 | ||
457 | const_debug unsigned int sysctl_sched_features = | |
bf5c91ba | 458 | SCHED_FEAT_NEW_FAIR_SLEEPERS *1 | |
94dfb5e7 | 459 | SCHED_FEAT_START_DEBIT *1 | |
06877c33 | 460 | SCHED_FEAT_TREE_AVG *0 | |
ce6c1311 | 461 | SCHED_FEAT_APPROX_AVG *0 | |
95938a35 MG |
462 | SCHED_FEAT_WAKEUP_PREEMPT *1 | |
463 | SCHED_FEAT_PREEMPT_RESTRICT *1; | |
bf5c91ba IM |
464 | |
465 | #define sched_feat(x) (sysctl_sched_features & SCHED_FEAT_##x) | |
466 | ||
e436d800 IM |
467 | /* |
468 | * For kernel-internal use: high-speed (but slightly incorrect) per-cpu | |
469 | * clock constructed from sched_clock(): | |
470 | */ | |
471 | unsigned long long cpu_clock(int cpu) | |
472 | { | |
e436d800 IM |
473 | unsigned long long now; |
474 | unsigned long flags; | |
b04a0f4c | 475 | struct rq *rq; |
e436d800 | 476 | |
2cd4d0ea | 477 | local_irq_save(flags); |
b04a0f4c IM |
478 | rq = cpu_rq(cpu); |
479 | update_rq_clock(rq); | |
480 | now = rq->clock; | |
2cd4d0ea | 481 | local_irq_restore(flags); |
e436d800 IM |
482 | |
483 | return now; | |
484 | } | |
a58f6f25 | 485 | EXPORT_SYMBOL_GPL(cpu_clock); |
e436d800 | 486 | |
1da177e4 | 487 | #ifndef prepare_arch_switch |
4866cde0 NP |
488 | # define prepare_arch_switch(next) do { } while (0) |
489 | #endif | |
490 | #ifndef finish_arch_switch | |
491 | # define finish_arch_switch(prev) do { } while (0) | |
492 | #endif | |
493 | ||
494 | #ifndef __ARCH_WANT_UNLOCKED_CTXSW | |
70b97a7f | 495 | static inline int task_running(struct rq *rq, struct task_struct *p) |
4866cde0 NP |
496 | { |
497 | return rq->curr == p; | |
498 | } | |
499 | ||
70b97a7f | 500 | static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next) |
4866cde0 NP |
501 | { |
502 | } | |
503 | ||
70b97a7f | 504 | static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev) |
4866cde0 | 505 | { |
da04c035 IM |
506 | #ifdef CONFIG_DEBUG_SPINLOCK |
507 | /* this is a valid case when another task releases the spinlock */ | |
508 | rq->lock.owner = current; | |
509 | #endif | |
8a25d5de IM |
510 | /* |
511 | * If we are tracking spinlock dependencies then we have to | |
512 | * fix up the runqueue lock - which gets 'carried over' from | |
513 | * prev into current: | |
514 | */ | |
515 | spin_acquire(&rq->lock.dep_map, 0, 0, _THIS_IP_); | |
516 | ||
4866cde0 NP |
517 | spin_unlock_irq(&rq->lock); |
518 | } | |
519 | ||
520 | #else /* __ARCH_WANT_UNLOCKED_CTXSW */ | |
70b97a7f | 521 | static inline int task_running(struct rq *rq, struct task_struct *p) |
4866cde0 NP |
522 | { |
523 | #ifdef CONFIG_SMP | |
524 | return p->oncpu; | |
525 | #else | |
526 | return rq->curr == p; | |
527 | #endif | |
528 | } | |
529 | ||
70b97a7f | 530 | static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next) |
4866cde0 NP |
531 | { |
532 | #ifdef CONFIG_SMP | |
533 | /* | |
534 | * We can optimise this out completely for !SMP, because the | |
535 | * SMP rebalancing from interrupt is the only thing that cares | |
536 | * here. | |
537 | */ | |
538 | next->oncpu = 1; | |
539 | #endif | |
540 | #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW | |
541 | spin_unlock_irq(&rq->lock); | |
542 | #else | |
543 | spin_unlock(&rq->lock); | |
544 | #endif | |
545 | } | |
546 | ||
70b97a7f | 547 | static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev) |
4866cde0 NP |
548 | { |
549 | #ifdef CONFIG_SMP | |
550 | /* | |
551 | * After ->oncpu is cleared, the task can be moved to a different CPU. | |
552 | * We must ensure this doesn't happen until the switch is completely | |
553 | * finished. | |
554 | */ | |
555 | smp_wmb(); | |
556 | prev->oncpu = 0; | |
557 | #endif | |
558 | #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW | |
559 | local_irq_enable(); | |
1da177e4 | 560 | #endif |
4866cde0 NP |
561 | } |
562 | #endif /* __ARCH_WANT_UNLOCKED_CTXSW */ | |
1da177e4 | 563 | |
b29739f9 IM |
564 | /* |
565 | * __task_rq_lock - lock the runqueue a given task resides on. | |
566 | * Must be called interrupts disabled. | |
567 | */ | |
70b97a7f | 568 | static inline struct rq *__task_rq_lock(struct task_struct *p) |
b29739f9 IM |
569 | __acquires(rq->lock) |
570 | { | |
3a5c359a AK |
571 | for (;;) { |
572 | struct rq *rq = task_rq(p); | |
573 | spin_lock(&rq->lock); | |
574 | if (likely(rq == task_rq(p))) | |
575 | return rq; | |
b29739f9 | 576 | spin_unlock(&rq->lock); |
b29739f9 | 577 | } |
b29739f9 IM |
578 | } |
579 | ||
1da177e4 LT |
580 | /* |
581 | * task_rq_lock - lock the runqueue a given task resides on and disable | |
582 | * interrupts. Note the ordering: we can safely lookup the task_rq without | |
583 | * explicitly disabling preemption. | |
584 | */ | |
70b97a7f | 585 | static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags) |
1da177e4 LT |
586 | __acquires(rq->lock) |
587 | { | |
70b97a7f | 588 | struct rq *rq; |
1da177e4 | 589 | |
3a5c359a AK |
590 | for (;;) { |
591 | local_irq_save(*flags); | |
592 | rq = task_rq(p); | |
593 | spin_lock(&rq->lock); | |
594 | if (likely(rq == task_rq(p))) | |
595 | return rq; | |
1da177e4 | 596 | spin_unlock_irqrestore(&rq->lock, *flags); |
1da177e4 | 597 | } |
1da177e4 LT |
598 | } |
599 | ||
a9957449 | 600 | static void __task_rq_unlock(struct rq *rq) |
b29739f9 IM |
601 | __releases(rq->lock) |
602 | { | |
603 | spin_unlock(&rq->lock); | |
604 | } | |
605 | ||
70b97a7f | 606 | static inline void task_rq_unlock(struct rq *rq, unsigned long *flags) |
1da177e4 LT |
607 | __releases(rq->lock) |
608 | { | |
609 | spin_unlock_irqrestore(&rq->lock, *flags); | |
610 | } | |
611 | ||
1da177e4 | 612 | /* |
cc2a73b5 | 613 | * this_rq_lock - lock this runqueue and disable interrupts. |
1da177e4 | 614 | */ |
a9957449 | 615 | static struct rq *this_rq_lock(void) |
1da177e4 LT |
616 | __acquires(rq->lock) |
617 | { | |
70b97a7f | 618 | struct rq *rq; |
1da177e4 LT |
619 | |
620 | local_irq_disable(); | |
621 | rq = this_rq(); | |
622 | spin_lock(&rq->lock); | |
623 | ||
624 | return rq; | |
625 | } | |
626 | ||
1b9f19c2 | 627 | /* |
2aa44d05 | 628 | * We are going deep-idle (irqs are disabled): |
1b9f19c2 | 629 | */ |
2aa44d05 | 630 | void sched_clock_idle_sleep_event(void) |
1b9f19c2 | 631 | { |
2aa44d05 IM |
632 | struct rq *rq = cpu_rq(smp_processor_id()); |
633 | ||
634 | spin_lock(&rq->lock); | |
635 | __update_rq_clock(rq); | |
636 | spin_unlock(&rq->lock); | |
637 | rq->clock_deep_idle_events++; | |
638 | } | |
639 | EXPORT_SYMBOL_GPL(sched_clock_idle_sleep_event); | |
640 | ||
641 | /* | |
642 | * We just idled delta nanoseconds (called with irqs disabled): | |
643 | */ | |
644 | void sched_clock_idle_wakeup_event(u64 delta_ns) | |
645 | { | |
646 | struct rq *rq = cpu_rq(smp_processor_id()); | |
647 | u64 now = sched_clock(); | |
1b9f19c2 | 648 | |
2aa44d05 IM |
649 | rq->idle_clock += delta_ns; |
650 | /* | |
651 | * Override the previous timestamp and ignore all | |
652 | * sched_clock() deltas that occured while we idled, | |
653 | * and use the PM-provided delta_ns to advance the | |
654 | * rq clock: | |
655 | */ | |
656 | spin_lock(&rq->lock); | |
657 | rq->prev_clock_raw = now; | |
658 | rq->clock += delta_ns; | |
659 | spin_unlock(&rq->lock); | |
1b9f19c2 | 660 | } |
2aa44d05 | 661 | EXPORT_SYMBOL_GPL(sched_clock_idle_wakeup_event); |
1b9f19c2 | 662 | |
c24d20db IM |
663 | /* |
664 | * resched_task - mark a task 'to be rescheduled now'. | |
665 | * | |
666 | * On UP this means the setting of the need_resched flag, on SMP it | |
667 | * might also involve a cross-CPU call to trigger the scheduler on | |
668 | * the target CPU. | |
669 | */ | |
670 | #ifdef CONFIG_SMP | |
671 | ||
672 | #ifndef tsk_is_polling | |
673 | #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG) | |
674 | #endif | |
675 | ||
676 | static void resched_task(struct task_struct *p) | |
677 | { | |
678 | int cpu; | |
679 | ||
680 | assert_spin_locked(&task_rq(p)->lock); | |
681 | ||
682 | if (unlikely(test_tsk_thread_flag(p, TIF_NEED_RESCHED))) | |
683 | return; | |
684 | ||
685 | set_tsk_thread_flag(p, TIF_NEED_RESCHED); | |
686 | ||
687 | cpu = task_cpu(p); | |
688 | if (cpu == smp_processor_id()) | |
689 | return; | |
690 | ||
691 | /* NEED_RESCHED must be visible before we test polling */ | |
692 | smp_mb(); | |
693 | if (!tsk_is_polling(p)) | |
694 | smp_send_reschedule(cpu); | |
695 | } | |
696 | ||
697 | static void resched_cpu(int cpu) | |
698 | { | |
699 | struct rq *rq = cpu_rq(cpu); | |
700 | unsigned long flags; | |
701 | ||
702 | if (!spin_trylock_irqsave(&rq->lock, flags)) | |
703 | return; | |
704 | resched_task(cpu_curr(cpu)); | |
705 | spin_unlock_irqrestore(&rq->lock, flags); | |
706 | } | |
707 | #else | |
708 | static inline void resched_task(struct task_struct *p) | |
709 | { | |
710 | assert_spin_locked(&task_rq(p)->lock); | |
711 | set_tsk_need_resched(p); | |
712 | } | |
713 | #endif | |
714 | ||
45bf76df IM |
715 | #if BITS_PER_LONG == 32 |
716 | # define WMULT_CONST (~0UL) | |
717 | #else | |
718 | # define WMULT_CONST (1UL << 32) | |
719 | #endif | |
720 | ||
721 | #define WMULT_SHIFT 32 | |
722 | ||
194081eb IM |
723 | /* |
724 | * Shift right and round: | |
725 | */ | |
cf2ab469 | 726 | #define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y)) |
194081eb | 727 | |
cb1c4fc9 | 728 | static unsigned long |
45bf76df IM |
729 | calc_delta_mine(unsigned long delta_exec, unsigned long weight, |
730 | struct load_weight *lw) | |
731 | { | |
732 | u64 tmp; | |
733 | ||
734 | if (unlikely(!lw->inv_weight)) | |
194081eb | 735 | lw->inv_weight = (WMULT_CONST - lw->weight/2) / lw->weight + 1; |
45bf76df IM |
736 | |
737 | tmp = (u64)delta_exec * weight; | |
738 | /* | |
739 | * Check whether we'd overflow the 64-bit multiplication: | |
740 | */ | |
194081eb | 741 | if (unlikely(tmp > WMULT_CONST)) |
cf2ab469 | 742 | tmp = SRR(SRR(tmp, WMULT_SHIFT/2) * lw->inv_weight, |
194081eb IM |
743 | WMULT_SHIFT/2); |
744 | else | |
cf2ab469 | 745 | tmp = SRR(tmp * lw->inv_weight, WMULT_SHIFT); |
45bf76df | 746 | |
ecf691da | 747 | return (unsigned long)min(tmp, (u64)(unsigned long)LONG_MAX); |
45bf76df IM |
748 | } |
749 | ||
750 | static inline unsigned long | |
751 | calc_delta_fair(unsigned long delta_exec, struct load_weight *lw) | |
752 | { | |
753 | return calc_delta_mine(delta_exec, NICE_0_LOAD, lw); | |
754 | } | |
755 | ||
1091985b | 756 | static inline void update_load_add(struct load_weight *lw, unsigned long inc) |
45bf76df IM |
757 | { |
758 | lw->weight += inc; | |
45bf76df IM |
759 | } |
760 | ||
1091985b | 761 | static inline void update_load_sub(struct load_weight *lw, unsigned long dec) |
45bf76df IM |
762 | { |
763 | lw->weight -= dec; | |
45bf76df IM |
764 | } |
765 | ||
2dd73a4f PW |
766 | /* |
767 | * To aid in avoiding the subversion of "niceness" due to uneven distribution | |
768 | * of tasks with abnormal "nice" values across CPUs the contribution that | |
769 | * each task makes to its run queue's load is weighted according to its | |
770 | * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a | |
771 | * scaled version of the new time slice allocation that they receive on time | |
772 | * slice expiry etc. | |
773 | */ | |
774 | ||
dd41f596 IM |
775 | #define WEIGHT_IDLEPRIO 2 |
776 | #define WMULT_IDLEPRIO (1 << 31) | |
777 | ||
778 | /* | |
779 | * Nice levels are multiplicative, with a gentle 10% change for every | |
780 | * nice level changed. I.e. when a CPU-bound task goes from nice 0 to | |
781 | * nice 1, it will get ~10% less CPU time than another CPU-bound task | |
782 | * that remained on nice 0. | |
783 | * | |
784 | * The "10% effect" is relative and cumulative: from _any_ nice level, | |
785 | * if you go up 1 level, it's -10% CPU usage, if you go down 1 level | |
f9153ee6 IM |
786 | * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25. |
787 | * If a task goes up by ~10% and another task goes down by ~10% then | |
788 | * the relative distance between them is ~25%.) | |
dd41f596 IM |
789 | */ |
790 | static const int prio_to_weight[40] = { | |
254753dc IM |
791 | /* -20 */ 88761, 71755, 56483, 46273, 36291, |
792 | /* -15 */ 29154, 23254, 18705, 14949, 11916, | |
793 | /* -10 */ 9548, 7620, 6100, 4904, 3906, | |
794 | /* -5 */ 3121, 2501, 1991, 1586, 1277, | |
795 | /* 0 */ 1024, 820, 655, 526, 423, | |
796 | /* 5 */ 335, 272, 215, 172, 137, | |
797 | /* 10 */ 110, 87, 70, 56, 45, | |
798 | /* 15 */ 36, 29, 23, 18, 15, | |
dd41f596 IM |
799 | }; |
800 | ||
5714d2de IM |
801 | /* |
802 | * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated. | |
803 | * | |
804 | * In cases where the weight does not change often, we can use the | |
805 | * precalculated inverse to speed up arithmetics by turning divisions | |
806 | * into multiplications: | |
807 | */ | |
dd41f596 | 808 | static const u32 prio_to_wmult[40] = { |
254753dc IM |
809 | /* -20 */ 48388, 59856, 76040, 92818, 118348, |
810 | /* -15 */ 147320, 184698, 229616, 287308, 360437, | |
811 | /* -10 */ 449829, 563644, 704093, 875809, 1099582, | |
812 | /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326, | |
813 | /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587, | |
814 | /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126, | |
815 | /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717, | |
816 | /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153, | |
dd41f596 | 817 | }; |
2dd73a4f | 818 | |
dd41f596 IM |
819 | static void activate_task(struct rq *rq, struct task_struct *p, int wakeup); |
820 | ||
821 | /* | |
822 | * runqueue iterator, to support SMP load-balancing between different | |
823 | * scheduling classes, without having to expose their internal data | |
824 | * structures to the load-balancing proper: | |
825 | */ | |
826 | struct rq_iterator { | |
827 | void *arg; | |
828 | struct task_struct *(*start)(void *); | |
829 | struct task_struct *(*next)(void *); | |
830 | }; | |
831 | ||
832 | static int balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
833 | unsigned long max_nr_move, unsigned long max_load_move, | |
834 | struct sched_domain *sd, enum cpu_idle_type idle, | |
835 | int *all_pinned, unsigned long *load_moved, | |
a4ac01c3 | 836 | int *this_best_prio, struct rq_iterator *iterator); |
dd41f596 IM |
837 | |
838 | #include "sched_stats.h" | |
dd41f596 | 839 | #include "sched_idletask.c" |
5522d5d5 IM |
840 | #include "sched_fair.c" |
841 | #include "sched_rt.c" | |
dd41f596 IM |
842 | #ifdef CONFIG_SCHED_DEBUG |
843 | # include "sched_debug.c" | |
844 | #endif | |
845 | ||
846 | #define sched_class_highest (&rt_sched_class) | |
847 | ||
9c217245 IM |
848 | /* |
849 | * Update delta_exec, delta_fair fields for rq. | |
850 | * | |
851 | * delta_fair clock advances at a rate inversely proportional to | |
495eca49 | 852 | * total load (rq->load.weight) on the runqueue, while |
9c217245 IM |
853 | * delta_exec advances at the same rate as wall-clock (provided |
854 | * cpu is not idle). | |
855 | * | |
856 | * delta_exec / delta_fair is a measure of the (smoothened) load on this | |
857 | * runqueue over any given interval. This (smoothened) load is used | |
858 | * during load balance. | |
859 | * | |
495eca49 | 860 | * This function is called /before/ updating rq->load |
9c217245 IM |
861 | * and when switching tasks. |
862 | */ | |
29b4b623 | 863 | static inline void inc_load(struct rq *rq, const struct task_struct *p) |
9c217245 | 864 | { |
495eca49 | 865 | update_load_add(&rq->load, p->se.load.weight); |
9c217245 IM |
866 | } |
867 | ||
79b5dddf | 868 | static inline void dec_load(struct rq *rq, const struct task_struct *p) |
9c217245 | 869 | { |
495eca49 | 870 | update_load_sub(&rq->load, p->se.load.weight); |
9c217245 IM |
871 | } |
872 | ||
e5fa2237 | 873 | static void inc_nr_running(struct task_struct *p, struct rq *rq) |
9c217245 IM |
874 | { |
875 | rq->nr_running++; | |
29b4b623 | 876 | inc_load(rq, p); |
9c217245 IM |
877 | } |
878 | ||
db53181e | 879 | static void dec_nr_running(struct task_struct *p, struct rq *rq) |
9c217245 IM |
880 | { |
881 | rq->nr_running--; | |
79b5dddf | 882 | dec_load(rq, p); |
9c217245 IM |
883 | } |
884 | ||
45bf76df IM |
885 | static void set_load_weight(struct task_struct *p) |
886 | { | |
887 | if (task_has_rt_policy(p)) { | |
dd41f596 IM |
888 | p->se.load.weight = prio_to_weight[0] * 2; |
889 | p->se.load.inv_weight = prio_to_wmult[0] >> 1; | |
890 | return; | |
891 | } | |
45bf76df | 892 | |
dd41f596 IM |
893 | /* |
894 | * SCHED_IDLE tasks get minimal weight: | |
895 | */ | |
896 | if (p->policy == SCHED_IDLE) { | |
897 | p->se.load.weight = WEIGHT_IDLEPRIO; | |
898 | p->se.load.inv_weight = WMULT_IDLEPRIO; | |
899 | return; | |
900 | } | |
71f8bd46 | 901 | |
dd41f596 IM |
902 | p->se.load.weight = prio_to_weight[p->static_prio - MAX_RT_PRIO]; |
903 | p->se.load.inv_weight = prio_to_wmult[p->static_prio - MAX_RT_PRIO]; | |
71f8bd46 IM |
904 | } |
905 | ||
8159f87e | 906 | static void enqueue_task(struct rq *rq, struct task_struct *p, int wakeup) |
71f8bd46 | 907 | { |
dd41f596 | 908 | sched_info_queued(p); |
fd390f6a | 909 | p->sched_class->enqueue_task(rq, p, wakeup); |
dd41f596 | 910 | p->se.on_rq = 1; |
71f8bd46 IM |
911 | } |
912 | ||
69be72c1 | 913 | static void dequeue_task(struct rq *rq, struct task_struct *p, int sleep) |
71f8bd46 | 914 | { |
f02231e5 | 915 | p->sched_class->dequeue_task(rq, p, sleep); |
dd41f596 | 916 | p->se.on_rq = 0; |
71f8bd46 IM |
917 | } |
918 | ||
14531189 | 919 | /* |
dd41f596 | 920 | * __normal_prio - return the priority that is based on the static prio |
14531189 | 921 | */ |
14531189 IM |
922 | static inline int __normal_prio(struct task_struct *p) |
923 | { | |
dd41f596 | 924 | return p->static_prio; |
14531189 IM |
925 | } |
926 | ||
b29739f9 IM |
927 | /* |
928 | * Calculate the expected normal priority: i.e. priority | |
929 | * without taking RT-inheritance into account. Might be | |
930 | * boosted by interactivity modifiers. Changes upon fork, | |
931 | * setprio syscalls, and whenever the interactivity | |
932 | * estimator recalculates. | |
933 | */ | |
36c8b586 | 934 | static inline int normal_prio(struct task_struct *p) |
b29739f9 IM |
935 | { |
936 | int prio; | |
937 | ||
e05606d3 | 938 | if (task_has_rt_policy(p)) |
b29739f9 IM |
939 | prio = MAX_RT_PRIO-1 - p->rt_priority; |
940 | else | |
941 | prio = __normal_prio(p); | |
942 | return prio; | |
943 | } | |
944 | ||
945 | /* | |
946 | * Calculate the current priority, i.e. the priority | |
947 | * taken into account by the scheduler. This value might | |
948 | * be boosted by RT tasks, or might be boosted by | |
949 | * interactivity modifiers. Will be RT if the task got | |
950 | * RT-boosted. If not then it returns p->normal_prio. | |
951 | */ | |
36c8b586 | 952 | static int effective_prio(struct task_struct *p) |
b29739f9 IM |
953 | { |
954 | p->normal_prio = normal_prio(p); | |
955 | /* | |
956 | * If we are RT tasks or we were boosted to RT priority, | |
957 | * keep the priority unchanged. Otherwise, update priority | |
958 | * to the normal priority: | |
959 | */ | |
960 | if (!rt_prio(p->prio)) | |
961 | return p->normal_prio; | |
962 | return p->prio; | |
963 | } | |
964 | ||
1da177e4 | 965 | /* |
dd41f596 | 966 | * activate_task - move a task to the runqueue. |
1da177e4 | 967 | */ |
dd41f596 | 968 | static void activate_task(struct rq *rq, struct task_struct *p, int wakeup) |
1da177e4 | 969 | { |
dd41f596 IM |
970 | if (p->state == TASK_UNINTERRUPTIBLE) |
971 | rq->nr_uninterruptible--; | |
1da177e4 | 972 | |
8159f87e | 973 | enqueue_task(rq, p, wakeup); |
e5fa2237 | 974 | inc_nr_running(p, rq); |
1da177e4 LT |
975 | } |
976 | ||
1da177e4 LT |
977 | /* |
978 | * deactivate_task - remove a task from the runqueue. | |
979 | */ | |
2e1cb74a | 980 | static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep) |
1da177e4 | 981 | { |
dd41f596 IM |
982 | if (p->state == TASK_UNINTERRUPTIBLE) |
983 | rq->nr_uninterruptible++; | |
984 | ||
69be72c1 | 985 | dequeue_task(rq, p, sleep); |
db53181e | 986 | dec_nr_running(p, rq); |
1da177e4 LT |
987 | } |
988 | ||
1da177e4 LT |
989 | /** |
990 | * task_curr - is this task currently executing on a CPU? | |
991 | * @p: the task in question. | |
992 | */ | |
36c8b586 | 993 | inline int task_curr(const struct task_struct *p) |
1da177e4 LT |
994 | { |
995 | return cpu_curr(task_cpu(p)) == p; | |
996 | } | |
997 | ||
2dd73a4f PW |
998 | /* Used instead of source_load when we know the type == 0 */ |
999 | unsigned long weighted_cpuload(const int cpu) | |
1000 | { | |
495eca49 | 1001 | return cpu_rq(cpu)->load.weight; |
dd41f596 IM |
1002 | } |
1003 | ||
1004 | static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu) | |
1005 | { | |
1006 | #ifdef CONFIG_SMP | |
1007 | task_thread_info(p)->cpu = cpu; | |
dd41f596 | 1008 | #endif |
29f59db3 | 1009 | set_task_cfs_rq(p); |
2dd73a4f PW |
1010 | } |
1011 | ||
1da177e4 | 1012 | #ifdef CONFIG_SMP |
c65cc870 | 1013 | |
dd41f596 | 1014 | void set_task_cpu(struct task_struct *p, unsigned int new_cpu) |
c65cc870 | 1015 | { |
dd41f596 IM |
1016 | int old_cpu = task_cpu(p); |
1017 | struct rq *old_rq = cpu_rq(old_cpu), *new_rq = cpu_rq(new_cpu); | |
2830cf8c SV |
1018 | struct cfs_rq *old_cfsrq = task_cfs_rq(p), |
1019 | *new_cfsrq = cpu_cfs_rq(old_cfsrq, new_cpu); | |
bbdba7c0 | 1020 | u64 clock_offset; |
dd41f596 IM |
1021 | |
1022 | clock_offset = old_rq->clock - new_rq->clock; | |
6cfb0d5d IM |
1023 | |
1024 | #ifdef CONFIG_SCHEDSTATS | |
1025 | if (p->se.wait_start) | |
1026 | p->se.wait_start -= clock_offset; | |
dd41f596 IM |
1027 | if (p->se.sleep_start) |
1028 | p->se.sleep_start -= clock_offset; | |
1029 | if (p->se.block_start) | |
1030 | p->se.block_start -= clock_offset; | |
6cfb0d5d | 1031 | #endif |
2830cf8c SV |
1032 | p->se.vruntime -= old_cfsrq->min_vruntime - |
1033 | new_cfsrq->min_vruntime; | |
dd41f596 IM |
1034 | |
1035 | __set_task_cpu(p, new_cpu); | |
c65cc870 IM |
1036 | } |
1037 | ||
70b97a7f | 1038 | struct migration_req { |
1da177e4 | 1039 | struct list_head list; |
1da177e4 | 1040 | |
36c8b586 | 1041 | struct task_struct *task; |
1da177e4 LT |
1042 | int dest_cpu; |
1043 | ||
1da177e4 | 1044 | struct completion done; |
70b97a7f | 1045 | }; |
1da177e4 LT |
1046 | |
1047 | /* | |
1048 | * The task's runqueue lock must be held. | |
1049 | * Returns true if you have to wait for migration thread. | |
1050 | */ | |
36c8b586 | 1051 | static int |
70b97a7f | 1052 | migrate_task(struct task_struct *p, int dest_cpu, struct migration_req *req) |
1da177e4 | 1053 | { |
70b97a7f | 1054 | struct rq *rq = task_rq(p); |
1da177e4 LT |
1055 | |
1056 | /* | |
1057 | * If the task is not on a runqueue (and not running), then | |
1058 | * it is sufficient to simply update the task's cpu field. | |
1059 | */ | |
dd41f596 | 1060 | if (!p->se.on_rq && !task_running(rq, p)) { |
1da177e4 LT |
1061 | set_task_cpu(p, dest_cpu); |
1062 | return 0; | |
1063 | } | |
1064 | ||
1065 | init_completion(&req->done); | |
1da177e4 LT |
1066 | req->task = p; |
1067 | req->dest_cpu = dest_cpu; | |
1068 | list_add(&req->list, &rq->migration_queue); | |
48f24c4d | 1069 | |
1da177e4 LT |
1070 | return 1; |
1071 | } | |
1072 | ||
1073 | /* | |
1074 | * wait_task_inactive - wait for a thread to unschedule. | |
1075 | * | |
1076 | * The caller must ensure that the task *will* unschedule sometime soon, | |
1077 | * else this function might spin for a *long* time. This function can't | |
1078 | * be called with interrupts off, or it may introduce deadlock with | |
1079 | * smp_call_function() if an IPI is sent by the same process we are | |
1080 | * waiting to become inactive. | |
1081 | */ | |
36c8b586 | 1082 | void wait_task_inactive(struct task_struct *p) |
1da177e4 LT |
1083 | { |
1084 | unsigned long flags; | |
dd41f596 | 1085 | int running, on_rq; |
70b97a7f | 1086 | struct rq *rq; |
1da177e4 | 1087 | |
3a5c359a AK |
1088 | for (;;) { |
1089 | /* | |
1090 | * We do the initial early heuristics without holding | |
1091 | * any task-queue locks at all. We'll only try to get | |
1092 | * the runqueue lock when things look like they will | |
1093 | * work out! | |
1094 | */ | |
1095 | rq = task_rq(p); | |
fa490cfd | 1096 | |
3a5c359a AK |
1097 | /* |
1098 | * If the task is actively running on another CPU | |
1099 | * still, just relax and busy-wait without holding | |
1100 | * any locks. | |
1101 | * | |
1102 | * NOTE! Since we don't hold any locks, it's not | |
1103 | * even sure that "rq" stays as the right runqueue! | |
1104 | * But we don't care, since "task_running()" will | |
1105 | * return false if the runqueue has changed and p | |
1106 | * is actually now running somewhere else! | |
1107 | */ | |
1108 | while (task_running(rq, p)) | |
1109 | cpu_relax(); | |
fa490cfd | 1110 | |
3a5c359a AK |
1111 | /* |
1112 | * Ok, time to look more closely! We need the rq | |
1113 | * lock now, to be *sure*. If we're wrong, we'll | |
1114 | * just go back and repeat. | |
1115 | */ | |
1116 | rq = task_rq_lock(p, &flags); | |
1117 | running = task_running(rq, p); | |
1118 | on_rq = p->se.on_rq; | |
1119 | task_rq_unlock(rq, &flags); | |
fa490cfd | 1120 | |
3a5c359a AK |
1121 | /* |
1122 | * Was it really running after all now that we | |
1123 | * checked with the proper locks actually held? | |
1124 | * | |
1125 | * Oops. Go back and try again.. | |
1126 | */ | |
1127 | if (unlikely(running)) { | |
1128 | cpu_relax(); | |
1129 | continue; | |
1130 | } | |
fa490cfd | 1131 | |
3a5c359a AK |
1132 | /* |
1133 | * It's not enough that it's not actively running, | |
1134 | * it must be off the runqueue _entirely_, and not | |
1135 | * preempted! | |
1136 | * | |
1137 | * So if it wa still runnable (but just not actively | |
1138 | * running right now), it's preempted, and we should | |
1139 | * yield - it could be a while. | |
1140 | */ | |
1141 | if (unlikely(on_rq)) { | |
1142 | schedule_timeout_uninterruptible(1); | |
1143 | continue; | |
1144 | } | |
fa490cfd | 1145 | |
3a5c359a AK |
1146 | /* |
1147 | * Ahh, all good. It wasn't running, and it wasn't | |
1148 | * runnable, which means that it will never become | |
1149 | * running in the future either. We're all done! | |
1150 | */ | |
1151 | break; | |
1152 | } | |
1da177e4 LT |
1153 | } |
1154 | ||
1155 | /*** | |
1156 | * kick_process - kick a running thread to enter/exit the kernel | |
1157 | * @p: the to-be-kicked thread | |
1158 | * | |
1159 | * Cause a process which is running on another CPU to enter | |
1160 | * kernel-mode, without any delay. (to get signals handled.) | |
1161 | * | |
1162 | * NOTE: this function doesnt have to take the runqueue lock, | |
1163 | * because all it wants to ensure is that the remote task enters | |
1164 | * the kernel. If the IPI races and the task has been migrated | |
1165 | * to another CPU then no harm is done and the purpose has been | |
1166 | * achieved as well. | |
1167 | */ | |
36c8b586 | 1168 | void kick_process(struct task_struct *p) |
1da177e4 LT |
1169 | { |
1170 | int cpu; | |
1171 | ||
1172 | preempt_disable(); | |
1173 | cpu = task_cpu(p); | |
1174 | if ((cpu != smp_processor_id()) && task_curr(p)) | |
1175 | smp_send_reschedule(cpu); | |
1176 | preempt_enable(); | |
1177 | } | |
1178 | ||
1179 | /* | |
2dd73a4f PW |
1180 | * Return a low guess at the load of a migration-source cpu weighted |
1181 | * according to the scheduling class and "nice" value. | |
1da177e4 LT |
1182 | * |
1183 | * We want to under-estimate the load of migration sources, to | |
1184 | * balance conservatively. | |
1185 | */ | |
a9957449 | 1186 | static unsigned long source_load(int cpu, int type) |
1da177e4 | 1187 | { |
70b97a7f | 1188 | struct rq *rq = cpu_rq(cpu); |
dd41f596 | 1189 | unsigned long total = weighted_cpuload(cpu); |
2dd73a4f | 1190 | |
3b0bd9bc | 1191 | if (type == 0) |
dd41f596 | 1192 | return total; |
b910472d | 1193 | |
dd41f596 | 1194 | return min(rq->cpu_load[type-1], total); |
1da177e4 LT |
1195 | } |
1196 | ||
1197 | /* | |
2dd73a4f PW |
1198 | * Return a high guess at the load of a migration-target cpu weighted |
1199 | * according to the scheduling class and "nice" value. | |
1da177e4 | 1200 | */ |
a9957449 | 1201 | static unsigned long target_load(int cpu, int type) |
1da177e4 | 1202 | { |
70b97a7f | 1203 | struct rq *rq = cpu_rq(cpu); |
dd41f596 | 1204 | unsigned long total = weighted_cpuload(cpu); |
2dd73a4f | 1205 | |
7897986b | 1206 | if (type == 0) |
dd41f596 | 1207 | return total; |
3b0bd9bc | 1208 | |
dd41f596 | 1209 | return max(rq->cpu_load[type-1], total); |
2dd73a4f PW |
1210 | } |
1211 | ||
1212 | /* | |
1213 | * Return the average load per task on the cpu's run queue | |
1214 | */ | |
1215 | static inline unsigned long cpu_avg_load_per_task(int cpu) | |
1216 | { | |
70b97a7f | 1217 | struct rq *rq = cpu_rq(cpu); |
dd41f596 | 1218 | unsigned long total = weighted_cpuload(cpu); |
2dd73a4f PW |
1219 | unsigned long n = rq->nr_running; |
1220 | ||
dd41f596 | 1221 | return n ? total / n : SCHED_LOAD_SCALE; |
1da177e4 LT |
1222 | } |
1223 | ||
147cbb4b NP |
1224 | /* |
1225 | * find_idlest_group finds and returns the least busy CPU group within the | |
1226 | * domain. | |
1227 | */ | |
1228 | static struct sched_group * | |
1229 | find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu) | |
1230 | { | |
1231 | struct sched_group *idlest = NULL, *this = NULL, *group = sd->groups; | |
1232 | unsigned long min_load = ULONG_MAX, this_load = 0; | |
1233 | int load_idx = sd->forkexec_idx; | |
1234 | int imbalance = 100 + (sd->imbalance_pct-100)/2; | |
1235 | ||
1236 | do { | |
1237 | unsigned long load, avg_load; | |
1238 | int local_group; | |
1239 | int i; | |
1240 | ||
da5a5522 BD |
1241 | /* Skip over this group if it has no CPUs allowed */ |
1242 | if (!cpus_intersects(group->cpumask, p->cpus_allowed)) | |
3a5c359a | 1243 | continue; |
da5a5522 | 1244 | |
147cbb4b | 1245 | local_group = cpu_isset(this_cpu, group->cpumask); |
147cbb4b NP |
1246 | |
1247 | /* Tally up the load of all CPUs in the group */ | |
1248 | avg_load = 0; | |
1249 | ||
1250 | for_each_cpu_mask(i, group->cpumask) { | |
1251 | /* Bias balancing toward cpus of our domain */ | |
1252 | if (local_group) | |
1253 | load = source_load(i, load_idx); | |
1254 | else | |
1255 | load = target_load(i, load_idx); | |
1256 | ||
1257 | avg_load += load; | |
1258 | } | |
1259 | ||
1260 | /* Adjust by relative CPU power of the group */ | |
5517d86b ED |
1261 | avg_load = sg_div_cpu_power(group, |
1262 | avg_load * SCHED_LOAD_SCALE); | |
147cbb4b NP |
1263 | |
1264 | if (local_group) { | |
1265 | this_load = avg_load; | |
1266 | this = group; | |
1267 | } else if (avg_load < min_load) { | |
1268 | min_load = avg_load; | |
1269 | idlest = group; | |
1270 | } | |
3a5c359a | 1271 | } while (group = group->next, group != sd->groups); |
147cbb4b NP |
1272 | |
1273 | if (!idlest || 100*this_load < imbalance*min_load) | |
1274 | return NULL; | |
1275 | return idlest; | |
1276 | } | |
1277 | ||
1278 | /* | |
0feaece9 | 1279 | * find_idlest_cpu - find the idlest cpu among the cpus in group. |
147cbb4b | 1280 | */ |
95cdf3b7 IM |
1281 | static int |
1282 | find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu) | |
147cbb4b | 1283 | { |
da5a5522 | 1284 | cpumask_t tmp; |
147cbb4b NP |
1285 | unsigned long load, min_load = ULONG_MAX; |
1286 | int idlest = -1; | |
1287 | int i; | |
1288 | ||
da5a5522 BD |
1289 | /* Traverse only the allowed CPUs */ |
1290 | cpus_and(tmp, group->cpumask, p->cpus_allowed); | |
1291 | ||
1292 | for_each_cpu_mask(i, tmp) { | |
2dd73a4f | 1293 | load = weighted_cpuload(i); |
147cbb4b NP |
1294 | |
1295 | if (load < min_load || (load == min_load && i == this_cpu)) { | |
1296 | min_load = load; | |
1297 | idlest = i; | |
1298 | } | |
1299 | } | |
1300 | ||
1301 | return idlest; | |
1302 | } | |
1303 | ||
476d139c NP |
1304 | /* |
1305 | * sched_balance_self: balance the current task (running on cpu) in domains | |
1306 | * that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and | |
1307 | * SD_BALANCE_EXEC. | |
1308 | * | |
1309 | * Balance, ie. select the least loaded group. | |
1310 | * | |
1311 | * Returns the target CPU number, or the same CPU if no balancing is needed. | |
1312 | * | |
1313 | * preempt must be disabled. | |
1314 | */ | |
1315 | static int sched_balance_self(int cpu, int flag) | |
1316 | { | |
1317 | struct task_struct *t = current; | |
1318 | struct sched_domain *tmp, *sd = NULL; | |
147cbb4b | 1319 | |
c96d145e | 1320 | for_each_domain(cpu, tmp) { |
9761eea8 IM |
1321 | /* |
1322 | * If power savings logic is enabled for a domain, stop there. | |
1323 | */ | |
5c45bf27 SS |
1324 | if (tmp->flags & SD_POWERSAVINGS_BALANCE) |
1325 | break; | |
476d139c NP |
1326 | if (tmp->flags & flag) |
1327 | sd = tmp; | |
c96d145e | 1328 | } |
476d139c NP |
1329 | |
1330 | while (sd) { | |
1331 | cpumask_t span; | |
1332 | struct sched_group *group; | |
1a848870 SS |
1333 | int new_cpu, weight; |
1334 | ||
1335 | if (!(sd->flags & flag)) { | |
1336 | sd = sd->child; | |
1337 | continue; | |
1338 | } | |
476d139c NP |
1339 | |
1340 | span = sd->span; | |
1341 | group = find_idlest_group(sd, t, cpu); | |
1a848870 SS |
1342 | if (!group) { |
1343 | sd = sd->child; | |
1344 | continue; | |
1345 | } | |
476d139c | 1346 | |
da5a5522 | 1347 | new_cpu = find_idlest_cpu(group, t, cpu); |
1a848870 SS |
1348 | if (new_cpu == -1 || new_cpu == cpu) { |
1349 | /* Now try balancing at a lower domain level of cpu */ | |
1350 | sd = sd->child; | |
1351 | continue; | |
1352 | } | |
476d139c | 1353 | |
1a848870 | 1354 | /* Now try balancing at a lower domain level of new_cpu */ |
476d139c | 1355 | cpu = new_cpu; |
476d139c NP |
1356 | sd = NULL; |
1357 | weight = cpus_weight(span); | |
1358 | for_each_domain(cpu, tmp) { | |
1359 | if (weight <= cpus_weight(tmp->span)) | |
1360 | break; | |
1361 | if (tmp->flags & flag) | |
1362 | sd = tmp; | |
1363 | } | |
1364 | /* while loop will break here if sd == NULL */ | |
1365 | } | |
1366 | ||
1367 | return cpu; | |
1368 | } | |
1369 | ||
1370 | #endif /* CONFIG_SMP */ | |
1da177e4 LT |
1371 | |
1372 | /* | |
1373 | * wake_idle() will wake a task on an idle cpu if task->cpu is | |
1374 | * not idle and an idle cpu is available. The span of cpus to | |
1375 | * search starts with cpus closest then further out as needed, | |
1376 | * so we always favor a closer, idle cpu. | |
1377 | * | |
1378 | * Returns the CPU we should wake onto. | |
1379 | */ | |
1380 | #if defined(ARCH_HAS_SCHED_WAKE_IDLE) | |
36c8b586 | 1381 | static int wake_idle(int cpu, struct task_struct *p) |
1da177e4 LT |
1382 | { |
1383 | cpumask_t tmp; | |
1384 | struct sched_domain *sd; | |
1385 | int i; | |
1386 | ||
4953198b SS |
1387 | /* |
1388 | * If it is idle, then it is the best cpu to run this task. | |
1389 | * | |
1390 | * This cpu is also the best, if it has more than one task already. | |
1391 | * Siblings must be also busy(in most cases) as they didn't already | |
1392 | * pickup the extra load from this cpu and hence we need not check | |
1393 | * sibling runqueue info. This will avoid the checks and cache miss | |
1394 | * penalities associated with that. | |
1395 | */ | |
1396 | if (idle_cpu(cpu) || cpu_rq(cpu)->nr_running > 1) | |
1da177e4 LT |
1397 | return cpu; |
1398 | ||
1399 | for_each_domain(cpu, sd) { | |
1400 | if (sd->flags & SD_WAKE_IDLE) { | |
e0f364f4 | 1401 | cpus_and(tmp, sd->span, p->cpus_allowed); |
1da177e4 LT |
1402 | for_each_cpu_mask(i, tmp) { |
1403 | if (idle_cpu(i)) | |
1404 | return i; | |
1405 | } | |
9761eea8 | 1406 | } else { |
e0f364f4 | 1407 | break; |
9761eea8 | 1408 | } |
1da177e4 LT |
1409 | } |
1410 | return cpu; | |
1411 | } | |
1412 | #else | |
36c8b586 | 1413 | static inline int wake_idle(int cpu, struct task_struct *p) |
1da177e4 LT |
1414 | { |
1415 | return cpu; | |
1416 | } | |
1417 | #endif | |
1418 | ||
1419 | /*** | |
1420 | * try_to_wake_up - wake up a thread | |
1421 | * @p: the to-be-woken-up thread | |
1422 | * @state: the mask of task states that can be woken | |
1423 | * @sync: do a synchronous wakeup? | |
1424 | * | |
1425 | * Put it on the run-queue if it's not already there. The "current" | |
1426 | * thread is always on the run-queue (except when the actual | |
1427 | * re-schedule is in progress), and as such you're allowed to do | |
1428 | * the simpler "current->state = TASK_RUNNING" to mark yourself | |
1429 | * runnable without the overhead of this. | |
1430 | * | |
1431 | * returns failure only if the task is already active. | |
1432 | */ | |
36c8b586 | 1433 | static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync) |
1da177e4 LT |
1434 | { |
1435 | int cpu, this_cpu, success = 0; | |
1436 | unsigned long flags; | |
1437 | long old_state; | |
70b97a7f | 1438 | struct rq *rq; |
1da177e4 | 1439 | #ifdef CONFIG_SMP |
7897986b | 1440 | struct sched_domain *sd, *this_sd = NULL; |
70b97a7f | 1441 | unsigned long load, this_load; |
1da177e4 LT |
1442 | int new_cpu; |
1443 | #endif | |
1444 | ||
1445 | rq = task_rq_lock(p, &flags); | |
1446 | old_state = p->state; | |
1447 | if (!(old_state & state)) | |
1448 | goto out; | |
1449 | ||
dd41f596 | 1450 | if (p->se.on_rq) |
1da177e4 LT |
1451 | goto out_running; |
1452 | ||
1453 | cpu = task_cpu(p); | |
1454 | this_cpu = smp_processor_id(); | |
1455 | ||
1456 | #ifdef CONFIG_SMP | |
1457 | if (unlikely(task_running(rq, p))) | |
1458 | goto out_activate; | |
1459 | ||
7897986b NP |
1460 | new_cpu = cpu; |
1461 | ||
2d72376b | 1462 | schedstat_inc(rq, ttwu_count); |
1da177e4 LT |
1463 | if (cpu == this_cpu) { |
1464 | schedstat_inc(rq, ttwu_local); | |
7897986b NP |
1465 | goto out_set_cpu; |
1466 | } | |
1467 | ||
1468 | for_each_domain(this_cpu, sd) { | |
1469 | if (cpu_isset(cpu, sd->span)) { | |
1470 | schedstat_inc(sd, ttwu_wake_remote); | |
1471 | this_sd = sd; | |
1472 | break; | |
1da177e4 LT |
1473 | } |
1474 | } | |
1da177e4 | 1475 | |
7897986b | 1476 | if (unlikely(!cpu_isset(this_cpu, p->cpus_allowed))) |
1da177e4 LT |
1477 | goto out_set_cpu; |
1478 | ||
1da177e4 | 1479 | /* |
7897986b | 1480 | * Check for affine wakeup and passive balancing possibilities. |
1da177e4 | 1481 | */ |
7897986b NP |
1482 | if (this_sd) { |
1483 | int idx = this_sd->wake_idx; | |
1484 | unsigned int imbalance; | |
1da177e4 | 1485 | |
a3f21bce NP |
1486 | imbalance = 100 + (this_sd->imbalance_pct - 100) / 2; |
1487 | ||
7897986b NP |
1488 | load = source_load(cpu, idx); |
1489 | this_load = target_load(this_cpu, idx); | |
1da177e4 | 1490 | |
7897986b NP |
1491 | new_cpu = this_cpu; /* Wake to this CPU if we can */ |
1492 | ||
a3f21bce NP |
1493 | if (this_sd->flags & SD_WAKE_AFFINE) { |
1494 | unsigned long tl = this_load; | |
33859f7f MOS |
1495 | unsigned long tl_per_task; |
1496 | ||
1497 | tl_per_task = cpu_avg_load_per_task(this_cpu); | |
2dd73a4f | 1498 | |
1da177e4 | 1499 | /* |
a3f21bce NP |
1500 | * If sync wakeup then subtract the (maximum possible) |
1501 | * effect of the currently running task from the load | |
1502 | * of the current CPU: | |
1da177e4 | 1503 | */ |
a3f21bce | 1504 | if (sync) |
dd41f596 | 1505 | tl -= current->se.load.weight; |
a3f21bce NP |
1506 | |
1507 | if ((tl <= load && | |
2dd73a4f | 1508 | tl + target_load(cpu, idx) <= tl_per_task) || |
dd41f596 | 1509 | 100*(tl + p->se.load.weight) <= imbalance*load) { |
a3f21bce NP |
1510 | /* |
1511 | * This domain has SD_WAKE_AFFINE and | |
1512 | * p is cache cold in this domain, and | |
1513 | * there is no bad imbalance. | |
1514 | */ | |
1515 | schedstat_inc(this_sd, ttwu_move_affine); | |
1516 | goto out_set_cpu; | |
1517 | } | |
1518 | } | |
1519 | ||
1520 | /* | |
1521 | * Start passive balancing when half the imbalance_pct | |
1522 | * limit is reached. | |
1523 | */ | |
1524 | if (this_sd->flags & SD_WAKE_BALANCE) { | |
1525 | if (imbalance*this_load <= 100*load) { | |
1526 | schedstat_inc(this_sd, ttwu_move_balance); | |
1527 | goto out_set_cpu; | |
1528 | } | |
1da177e4 LT |
1529 | } |
1530 | } | |
1531 | ||
1532 | new_cpu = cpu; /* Could not wake to this_cpu. Wake to cpu instead */ | |
1533 | out_set_cpu: | |
1534 | new_cpu = wake_idle(new_cpu, p); | |
1535 | if (new_cpu != cpu) { | |
1536 | set_task_cpu(p, new_cpu); | |
1537 | task_rq_unlock(rq, &flags); | |
1538 | /* might preempt at this point */ | |
1539 | rq = task_rq_lock(p, &flags); | |
1540 | old_state = p->state; | |
1541 | if (!(old_state & state)) | |
1542 | goto out; | |
dd41f596 | 1543 | if (p->se.on_rq) |
1da177e4 LT |
1544 | goto out_running; |
1545 | ||
1546 | this_cpu = smp_processor_id(); | |
1547 | cpu = task_cpu(p); | |
1548 | } | |
1549 | ||
1550 | out_activate: | |
1551 | #endif /* CONFIG_SMP */ | |
2daa3577 | 1552 | update_rq_clock(rq); |
dd41f596 | 1553 | activate_task(rq, p, 1); |
1da177e4 LT |
1554 | /* |
1555 | * Sync wakeups (i.e. those types of wakeups where the waker | |
1556 | * has indicated that it will leave the CPU in short order) | |
1557 | * don't trigger a preemption, if the woken up task will run on | |
1558 | * this cpu. (in this case the 'I will reschedule' promise of | |
1559 | * the waker guarantees that the freshly woken up task is going | |
1560 | * to be considered on this CPU.) | |
1561 | */ | |
dd41f596 IM |
1562 | if (!sync || cpu != this_cpu) |
1563 | check_preempt_curr(rq, p); | |
1da177e4 LT |
1564 | success = 1; |
1565 | ||
1566 | out_running: | |
1567 | p->state = TASK_RUNNING; | |
1568 | out: | |
1569 | task_rq_unlock(rq, &flags); | |
1570 | ||
1571 | return success; | |
1572 | } | |
1573 | ||
36c8b586 | 1574 | int fastcall wake_up_process(struct task_struct *p) |
1da177e4 LT |
1575 | { |
1576 | return try_to_wake_up(p, TASK_STOPPED | TASK_TRACED | | |
1577 | TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE, 0); | |
1578 | } | |
1da177e4 LT |
1579 | EXPORT_SYMBOL(wake_up_process); |
1580 | ||
36c8b586 | 1581 | int fastcall wake_up_state(struct task_struct *p, unsigned int state) |
1da177e4 LT |
1582 | { |
1583 | return try_to_wake_up(p, state, 0); | |
1584 | } | |
1585 | ||
1da177e4 LT |
1586 | /* |
1587 | * Perform scheduler related setup for a newly forked process p. | |
1588 | * p is forked by current. | |
dd41f596 IM |
1589 | * |
1590 | * __sched_fork() is basic setup used by init_idle() too: | |
1591 | */ | |
1592 | static void __sched_fork(struct task_struct *p) | |
1593 | { | |
dd41f596 IM |
1594 | p->se.exec_start = 0; |
1595 | p->se.sum_exec_runtime = 0; | |
f6cf891c | 1596 | p->se.prev_sum_exec_runtime = 0; |
6cfb0d5d IM |
1597 | |
1598 | #ifdef CONFIG_SCHEDSTATS | |
1599 | p->se.wait_start = 0; | |
dd41f596 IM |
1600 | p->se.sum_sleep_runtime = 0; |
1601 | p->se.sleep_start = 0; | |
dd41f596 IM |
1602 | p->se.block_start = 0; |
1603 | p->se.sleep_max = 0; | |
1604 | p->se.block_max = 0; | |
1605 | p->se.exec_max = 0; | |
eba1ed4b | 1606 | p->se.slice_max = 0; |
dd41f596 | 1607 | p->se.wait_max = 0; |
6cfb0d5d | 1608 | #endif |
476d139c | 1609 | |
dd41f596 IM |
1610 | INIT_LIST_HEAD(&p->run_list); |
1611 | p->se.on_rq = 0; | |
476d139c | 1612 | |
e107be36 AK |
1613 | #ifdef CONFIG_PREEMPT_NOTIFIERS |
1614 | INIT_HLIST_HEAD(&p->preempt_notifiers); | |
1615 | #endif | |
1616 | ||
1da177e4 LT |
1617 | /* |
1618 | * We mark the process as running here, but have not actually | |
1619 | * inserted it onto the runqueue yet. This guarantees that | |
1620 | * nobody will actually run it, and a signal or other external | |
1621 | * event cannot wake it up and insert it on the runqueue either. | |
1622 | */ | |
1623 | p->state = TASK_RUNNING; | |
dd41f596 IM |
1624 | } |
1625 | ||
1626 | /* | |
1627 | * fork()/clone()-time setup: | |
1628 | */ | |
1629 | void sched_fork(struct task_struct *p, int clone_flags) | |
1630 | { | |
1631 | int cpu = get_cpu(); | |
1632 | ||
1633 | __sched_fork(p); | |
1634 | ||
1635 | #ifdef CONFIG_SMP | |
1636 | cpu = sched_balance_self(cpu, SD_BALANCE_FORK); | |
1637 | #endif | |
02e4bac2 | 1638 | set_task_cpu(p, cpu); |
b29739f9 IM |
1639 | |
1640 | /* | |
1641 | * Make sure we do not leak PI boosting priority to the child: | |
1642 | */ | |
1643 | p->prio = current->normal_prio; | |
2ddbf952 HS |
1644 | if (!rt_prio(p->prio)) |
1645 | p->sched_class = &fair_sched_class; | |
b29739f9 | 1646 | |
52f17b6c | 1647 | #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) |
dd41f596 | 1648 | if (likely(sched_info_on())) |
52f17b6c | 1649 | memset(&p->sched_info, 0, sizeof(p->sched_info)); |
1da177e4 | 1650 | #endif |
d6077cb8 | 1651 | #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW) |
4866cde0 NP |
1652 | p->oncpu = 0; |
1653 | #endif | |
1da177e4 | 1654 | #ifdef CONFIG_PREEMPT |
4866cde0 | 1655 | /* Want to start with kernel preemption disabled. */ |
a1261f54 | 1656 | task_thread_info(p)->preempt_count = 1; |
1da177e4 | 1657 | #endif |
476d139c | 1658 | put_cpu(); |
1da177e4 LT |
1659 | } |
1660 | ||
1661 | /* | |
1662 | * wake_up_new_task - wake up a newly created task for the first time. | |
1663 | * | |
1664 | * This function will do some initial scheduler statistics housekeeping | |
1665 | * that must be done for every newly created context, then puts the task | |
1666 | * on the runqueue and wakes it. | |
1667 | */ | |
36c8b586 | 1668 | void fastcall wake_up_new_task(struct task_struct *p, unsigned long clone_flags) |
1da177e4 LT |
1669 | { |
1670 | unsigned long flags; | |
dd41f596 | 1671 | struct rq *rq; |
1da177e4 LT |
1672 | |
1673 | rq = task_rq_lock(p, &flags); | |
147cbb4b | 1674 | BUG_ON(p->state != TASK_RUNNING); |
a8e504d2 | 1675 | update_rq_clock(rq); |
1da177e4 LT |
1676 | |
1677 | p->prio = effective_prio(p); | |
1678 | ||
00bf7bfc | 1679 | if (!p->sched_class->task_new || !current->se.on_rq || !rq->cfs.curr) { |
dd41f596 | 1680 | activate_task(rq, p, 0); |
1da177e4 | 1681 | } else { |
1da177e4 | 1682 | /* |
dd41f596 IM |
1683 | * Let the scheduling class do new task startup |
1684 | * management (if any): | |
1da177e4 | 1685 | */ |
ee0827d8 | 1686 | p->sched_class->task_new(rq, p); |
e5fa2237 | 1687 | inc_nr_running(p, rq); |
1da177e4 | 1688 | } |
dd41f596 IM |
1689 | check_preempt_curr(rq, p); |
1690 | task_rq_unlock(rq, &flags); | |
1da177e4 LT |
1691 | } |
1692 | ||
e107be36 AK |
1693 | #ifdef CONFIG_PREEMPT_NOTIFIERS |
1694 | ||
1695 | /** | |
421cee29 RD |
1696 | * preempt_notifier_register - tell me when current is being being preempted & rescheduled |
1697 | * @notifier: notifier struct to register | |
e107be36 AK |
1698 | */ |
1699 | void preempt_notifier_register(struct preempt_notifier *notifier) | |
1700 | { | |
1701 | hlist_add_head(¬ifier->link, ¤t->preempt_notifiers); | |
1702 | } | |
1703 | EXPORT_SYMBOL_GPL(preempt_notifier_register); | |
1704 | ||
1705 | /** | |
1706 | * preempt_notifier_unregister - no longer interested in preemption notifications | |
421cee29 | 1707 | * @notifier: notifier struct to unregister |
e107be36 AK |
1708 | * |
1709 | * This is safe to call from within a preemption notifier. | |
1710 | */ | |
1711 | void preempt_notifier_unregister(struct preempt_notifier *notifier) | |
1712 | { | |
1713 | hlist_del(¬ifier->link); | |
1714 | } | |
1715 | EXPORT_SYMBOL_GPL(preempt_notifier_unregister); | |
1716 | ||
1717 | static void fire_sched_in_preempt_notifiers(struct task_struct *curr) | |
1718 | { | |
1719 | struct preempt_notifier *notifier; | |
1720 | struct hlist_node *node; | |
1721 | ||
1722 | hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link) | |
1723 | notifier->ops->sched_in(notifier, raw_smp_processor_id()); | |
1724 | } | |
1725 | ||
1726 | static void | |
1727 | fire_sched_out_preempt_notifiers(struct task_struct *curr, | |
1728 | struct task_struct *next) | |
1729 | { | |
1730 | struct preempt_notifier *notifier; | |
1731 | struct hlist_node *node; | |
1732 | ||
1733 | hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link) | |
1734 | notifier->ops->sched_out(notifier, next); | |
1735 | } | |
1736 | ||
1737 | #else | |
1738 | ||
1739 | static void fire_sched_in_preempt_notifiers(struct task_struct *curr) | |
1740 | { | |
1741 | } | |
1742 | ||
1743 | static void | |
1744 | fire_sched_out_preempt_notifiers(struct task_struct *curr, | |
1745 | struct task_struct *next) | |
1746 | { | |
1747 | } | |
1748 | ||
1749 | #endif | |
1750 | ||
4866cde0 NP |
1751 | /** |
1752 | * prepare_task_switch - prepare to switch tasks | |
1753 | * @rq: the runqueue preparing to switch | |
421cee29 | 1754 | * @prev: the current task that is being switched out |
4866cde0 NP |
1755 | * @next: the task we are going to switch to. |
1756 | * | |
1757 | * This is called with the rq lock held and interrupts off. It must | |
1758 | * be paired with a subsequent finish_task_switch after the context | |
1759 | * switch. | |
1760 | * | |
1761 | * prepare_task_switch sets up locking and calls architecture specific | |
1762 | * hooks. | |
1763 | */ | |
e107be36 AK |
1764 | static inline void |
1765 | prepare_task_switch(struct rq *rq, struct task_struct *prev, | |
1766 | struct task_struct *next) | |
4866cde0 | 1767 | { |
e107be36 | 1768 | fire_sched_out_preempt_notifiers(prev, next); |
4866cde0 NP |
1769 | prepare_lock_switch(rq, next); |
1770 | prepare_arch_switch(next); | |
1771 | } | |
1772 | ||
1da177e4 LT |
1773 | /** |
1774 | * finish_task_switch - clean up after a task-switch | |
344babaa | 1775 | * @rq: runqueue associated with task-switch |
1da177e4 LT |
1776 | * @prev: the thread we just switched away from. |
1777 | * | |
4866cde0 NP |
1778 | * finish_task_switch must be called after the context switch, paired |
1779 | * with a prepare_task_switch call before the context switch. | |
1780 | * finish_task_switch will reconcile locking set up by prepare_task_switch, | |
1781 | * and do any other architecture-specific cleanup actions. | |
1da177e4 LT |
1782 | * |
1783 | * Note that we may have delayed dropping an mm in context_switch(). If | |
1784 | * so, we finish that here outside of the runqueue lock. (Doing it | |
1785 | * with the lock held can cause deadlocks; see schedule() for | |
1786 | * details.) | |
1787 | */ | |
a9957449 | 1788 | static void finish_task_switch(struct rq *rq, struct task_struct *prev) |
1da177e4 LT |
1789 | __releases(rq->lock) |
1790 | { | |
1da177e4 | 1791 | struct mm_struct *mm = rq->prev_mm; |
55a101f8 | 1792 | long prev_state; |
1da177e4 LT |
1793 | |
1794 | rq->prev_mm = NULL; | |
1795 | ||
1796 | /* | |
1797 | * A task struct has one reference for the use as "current". | |
c394cc9f | 1798 | * If a task dies, then it sets TASK_DEAD in tsk->state and calls |
55a101f8 ON |
1799 | * schedule one last time. The schedule call will never return, and |
1800 | * the scheduled task must drop that reference. | |
c394cc9f | 1801 | * The test for TASK_DEAD must occur while the runqueue locks are |
1da177e4 LT |
1802 | * still held, otherwise prev could be scheduled on another cpu, die |
1803 | * there before we look at prev->state, and then the reference would | |
1804 | * be dropped twice. | |
1805 | * Manfred Spraul <manfred@colorfullife.com> | |
1806 | */ | |
55a101f8 | 1807 | prev_state = prev->state; |
4866cde0 NP |
1808 | finish_arch_switch(prev); |
1809 | finish_lock_switch(rq, prev); | |
e107be36 | 1810 | fire_sched_in_preempt_notifiers(current); |
1da177e4 LT |
1811 | if (mm) |
1812 | mmdrop(mm); | |
c394cc9f | 1813 | if (unlikely(prev_state == TASK_DEAD)) { |
c6fd91f0 | 1814 | /* |
1815 | * Remove function-return probe instances associated with this | |
1816 | * task and put them back on the free list. | |
9761eea8 | 1817 | */ |
c6fd91f0 | 1818 | kprobe_flush_task(prev); |
1da177e4 | 1819 | put_task_struct(prev); |
c6fd91f0 | 1820 | } |
1da177e4 LT |
1821 | } |
1822 | ||
1823 | /** | |
1824 | * schedule_tail - first thing a freshly forked thread must call. | |
1825 | * @prev: the thread we just switched away from. | |
1826 | */ | |
36c8b586 | 1827 | asmlinkage void schedule_tail(struct task_struct *prev) |
1da177e4 LT |
1828 | __releases(rq->lock) |
1829 | { | |
70b97a7f IM |
1830 | struct rq *rq = this_rq(); |
1831 | ||
4866cde0 NP |
1832 | finish_task_switch(rq, prev); |
1833 | #ifdef __ARCH_WANT_UNLOCKED_CTXSW | |
1834 | /* In this case, finish_task_switch does not reenable preemption */ | |
1835 | preempt_enable(); | |
1836 | #endif | |
1da177e4 LT |
1837 | if (current->set_child_tid) |
1838 | put_user(current->pid, current->set_child_tid); | |
1839 | } | |
1840 | ||
1841 | /* | |
1842 | * context_switch - switch to the new MM and the new | |
1843 | * thread's register state. | |
1844 | */ | |
dd41f596 | 1845 | static inline void |
70b97a7f | 1846 | context_switch(struct rq *rq, struct task_struct *prev, |
36c8b586 | 1847 | struct task_struct *next) |
1da177e4 | 1848 | { |
dd41f596 | 1849 | struct mm_struct *mm, *oldmm; |
1da177e4 | 1850 | |
e107be36 | 1851 | prepare_task_switch(rq, prev, next); |
dd41f596 IM |
1852 | mm = next->mm; |
1853 | oldmm = prev->active_mm; | |
9226d125 ZA |
1854 | /* |
1855 | * For paravirt, this is coupled with an exit in switch_to to | |
1856 | * combine the page table reload and the switch backend into | |
1857 | * one hypercall. | |
1858 | */ | |
1859 | arch_enter_lazy_cpu_mode(); | |
1860 | ||
dd41f596 | 1861 | if (unlikely(!mm)) { |
1da177e4 LT |
1862 | next->active_mm = oldmm; |
1863 | atomic_inc(&oldmm->mm_count); | |
1864 | enter_lazy_tlb(oldmm, next); | |
1865 | } else | |
1866 | switch_mm(oldmm, mm, next); | |
1867 | ||
dd41f596 | 1868 | if (unlikely(!prev->mm)) { |
1da177e4 | 1869 | prev->active_mm = NULL; |
1da177e4 LT |
1870 | rq->prev_mm = oldmm; |
1871 | } | |
3a5f5e48 IM |
1872 | /* |
1873 | * Since the runqueue lock will be released by the next | |
1874 | * task (which is an invalid locking op but in the case | |
1875 | * of the scheduler it's an obvious special-case), so we | |
1876 | * do an early lockdep release here: | |
1877 | */ | |
1878 | #ifndef __ARCH_WANT_UNLOCKED_CTXSW | |
8a25d5de | 1879 | spin_release(&rq->lock.dep_map, 1, _THIS_IP_); |
3a5f5e48 | 1880 | #endif |
1da177e4 LT |
1881 | |
1882 | /* Here we just switch the register state and the stack. */ | |
1883 | switch_to(prev, next, prev); | |
1884 | ||
dd41f596 IM |
1885 | barrier(); |
1886 | /* | |
1887 | * this_rq must be evaluated again because prev may have moved | |
1888 | * CPUs since it called schedule(), thus the 'rq' on its stack | |
1889 | * frame will be invalid. | |
1890 | */ | |
1891 | finish_task_switch(this_rq(), prev); | |
1da177e4 LT |
1892 | } |
1893 | ||
1894 | /* | |
1895 | * nr_running, nr_uninterruptible and nr_context_switches: | |
1896 | * | |
1897 | * externally visible scheduler statistics: current number of runnable | |
1898 | * threads, current number of uninterruptible-sleeping threads, total | |
1899 | * number of context switches performed since bootup. | |
1900 | */ | |
1901 | unsigned long nr_running(void) | |
1902 | { | |
1903 | unsigned long i, sum = 0; | |
1904 | ||
1905 | for_each_online_cpu(i) | |
1906 | sum += cpu_rq(i)->nr_running; | |
1907 | ||
1908 | return sum; | |
1909 | } | |
1910 | ||
1911 | unsigned long nr_uninterruptible(void) | |
1912 | { | |
1913 | unsigned long i, sum = 0; | |
1914 | ||
0a945022 | 1915 | for_each_possible_cpu(i) |
1da177e4 LT |
1916 | sum += cpu_rq(i)->nr_uninterruptible; |
1917 | ||
1918 | /* | |
1919 | * Since we read the counters lockless, it might be slightly | |
1920 | * inaccurate. Do not allow it to go below zero though: | |
1921 | */ | |
1922 | if (unlikely((long)sum < 0)) | |
1923 | sum = 0; | |
1924 | ||
1925 | return sum; | |
1926 | } | |
1927 | ||
1928 | unsigned long long nr_context_switches(void) | |
1929 | { | |
cc94abfc SR |
1930 | int i; |
1931 | unsigned long long sum = 0; | |
1da177e4 | 1932 | |
0a945022 | 1933 | for_each_possible_cpu(i) |
1da177e4 LT |
1934 | sum += cpu_rq(i)->nr_switches; |
1935 | ||
1936 | return sum; | |
1937 | } | |
1938 | ||
1939 | unsigned long nr_iowait(void) | |
1940 | { | |
1941 | unsigned long i, sum = 0; | |
1942 | ||
0a945022 | 1943 | for_each_possible_cpu(i) |
1da177e4 LT |
1944 | sum += atomic_read(&cpu_rq(i)->nr_iowait); |
1945 | ||
1946 | return sum; | |
1947 | } | |
1948 | ||
db1b1fef JS |
1949 | unsigned long nr_active(void) |
1950 | { | |
1951 | unsigned long i, running = 0, uninterruptible = 0; | |
1952 | ||
1953 | for_each_online_cpu(i) { | |
1954 | running += cpu_rq(i)->nr_running; | |
1955 | uninterruptible += cpu_rq(i)->nr_uninterruptible; | |
1956 | } | |
1957 | ||
1958 | if (unlikely((long)uninterruptible < 0)) | |
1959 | uninterruptible = 0; | |
1960 | ||
1961 | return running + uninterruptible; | |
1962 | } | |
1963 | ||
48f24c4d | 1964 | /* |
dd41f596 IM |
1965 | * Update rq->cpu_load[] statistics. This function is usually called every |
1966 | * scheduler tick (TICK_NSEC). | |
48f24c4d | 1967 | */ |
dd41f596 | 1968 | static void update_cpu_load(struct rq *this_rq) |
48f24c4d | 1969 | { |
495eca49 | 1970 | unsigned long this_load = this_rq->load.weight; |
dd41f596 IM |
1971 | int i, scale; |
1972 | ||
1973 | this_rq->nr_load_updates++; | |
dd41f596 IM |
1974 | |
1975 | /* Update our load: */ | |
1976 | for (i = 0, scale = 1; i < CPU_LOAD_IDX_MAX; i++, scale += scale) { | |
1977 | unsigned long old_load, new_load; | |
1978 | ||
1979 | /* scale is effectively 1 << i now, and >> i divides by scale */ | |
1980 | ||
1981 | old_load = this_rq->cpu_load[i]; | |
1982 | new_load = this_load; | |
a25707f3 IM |
1983 | /* |
1984 | * Round up the averaging division if load is increasing. This | |
1985 | * prevents us from getting stuck on 9 if the load is 10, for | |
1986 | * example. | |
1987 | */ | |
1988 | if (new_load > old_load) | |
1989 | new_load += scale-1; | |
dd41f596 IM |
1990 | this_rq->cpu_load[i] = (old_load*(scale-1) + new_load) >> i; |
1991 | } | |
48f24c4d IM |
1992 | } |
1993 | ||
dd41f596 IM |
1994 | #ifdef CONFIG_SMP |
1995 | ||
1da177e4 LT |
1996 | /* |
1997 | * double_rq_lock - safely lock two runqueues | |
1998 | * | |
1999 | * Note this does not disable interrupts like task_rq_lock, | |
2000 | * you need to do so manually before calling. | |
2001 | */ | |
70b97a7f | 2002 | static void double_rq_lock(struct rq *rq1, struct rq *rq2) |
1da177e4 LT |
2003 | __acquires(rq1->lock) |
2004 | __acquires(rq2->lock) | |
2005 | { | |
054b9108 | 2006 | BUG_ON(!irqs_disabled()); |
1da177e4 LT |
2007 | if (rq1 == rq2) { |
2008 | spin_lock(&rq1->lock); | |
2009 | __acquire(rq2->lock); /* Fake it out ;) */ | |
2010 | } else { | |
c96d145e | 2011 | if (rq1 < rq2) { |
1da177e4 LT |
2012 | spin_lock(&rq1->lock); |
2013 | spin_lock(&rq2->lock); | |
2014 | } else { | |
2015 | spin_lock(&rq2->lock); | |
2016 | spin_lock(&rq1->lock); | |
2017 | } | |
2018 | } | |
6e82a3be IM |
2019 | update_rq_clock(rq1); |
2020 | update_rq_clock(rq2); | |
1da177e4 LT |
2021 | } |
2022 | ||
2023 | /* | |
2024 | * double_rq_unlock - safely unlock two runqueues | |
2025 | * | |
2026 | * Note this does not restore interrupts like task_rq_unlock, | |
2027 | * you need to do so manually after calling. | |
2028 | */ | |
70b97a7f | 2029 | static void double_rq_unlock(struct rq *rq1, struct rq *rq2) |
1da177e4 LT |
2030 | __releases(rq1->lock) |
2031 | __releases(rq2->lock) | |
2032 | { | |
2033 | spin_unlock(&rq1->lock); | |
2034 | if (rq1 != rq2) | |
2035 | spin_unlock(&rq2->lock); | |
2036 | else | |
2037 | __release(rq2->lock); | |
2038 | } | |
2039 | ||
2040 | /* | |
2041 | * double_lock_balance - lock the busiest runqueue, this_rq is locked already. | |
2042 | */ | |
70b97a7f | 2043 | static void double_lock_balance(struct rq *this_rq, struct rq *busiest) |
1da177e4 LT |
2044 | __releases(this_rq->lock) |
2045 | __acquires(busiest->lock) | |
2046 | __acquires(this_rq->lock) | |
2047 | { | |
054b9108 KK |
2048 | if (unlikely(!irqs_disabled())) { |
2049 | /* printk() doesn't work good under rq->lock */ | |
2050 | spin_unlock(&this_rq->lock); | |
2051 | BUG_ON(1); | |
2052 | } | |
1da177e4 | 2053 | if (unlikely(!spin_trylock(&busiest->lock))) { |
c96d145e | 2054 | if (busiest < this_rq) { |
1da177e4 LT |
2055 | spin_unlock(&this_rq->lock); |
2056 | spin_lock(&busiest->lock); | |
2057 | spin_lock(&this_rq->lock); | |
2058 | } else | |
2059 | spin_lock(&busiest->lock); | |
2060 | } | |
2061 | } | |
2062 | ||
1da177e4 LT |
2063 | /* |
2064 | * If dest_cpu is allowed for this process, migrate the task to it. | |
2065 | * This is accomplished by forcing the cpu_allowed mask to only | |
2066 | * allow dest_cpu, which will force the cpu onto dest_cpu. Then | |
2067 | * the cpu_allowed mask is restored. | |
2068 | */ | |
36c8b586 | 2069 | static void sched_migrate_task(struct task_struct *p, int dest_cpu) |
1da177e4 | 2070 | { |
70b97a7f | 2071 | struct migration_req req; |
1da177e4 | 2072 | unsigned long flags; |
70b97a7f | 2073 | struct rq *rq; |
1da177e4 LT |
2074 | |
2075 | rq = task_rq_lock(p, &flags); | |
2076 | if (!cpu_isset(dest_cpu, p->cpus_allowed) | |
2077 | || unlikely(cpu_is_offline(dest_cpu))) | |
2078 | goto out; | |
2079 | ||
2080 | /* force the process onto the specified CPU */ | |
2081 | if (migrate_task(p, dest_cpu, &req)) { | |
2082 | /* Need to wait for migration thread (might exit: take ref). */ | |
2083 | struct task_struct *mt = rq->migration_thread; | |
36c8b586 | 2084 | |
1da177e4 LT |
2085 | get_task_struct(mt); |
2086 | task_rq_unlock(rq, &flags); | |
2087 | wake_up_process(mt); | |
2088 | put_task_struct(mt); | |
2089 | wait_for_completion(&req.done); | |
36c8b586 | 2090 | |
1da177e4 LT |
2091 | return; |
2092 | } | |
2093 | out: | |
2094 | task_rq_unlock(rq, &flags); | |
2095 | } | |
2096 | ||
2097 | /* | |
476d139c NP |
2098 | * sched_exec - execve() is a valuable balancing opportunity, because at |
2099 | * this point the task has the smallest effective memory and cache footprint. | |
1da177e4 LT |
2100 | */ |
2101 | void sched_exec(void) | |
2102 | { | |
1da177e4 | 2103 | int new_cpu, this_cpu = get_cpu(); |
476d139c | 2104 | new_cpu = sched_balance_self(this_cpu, SD_BALANCE_EXEC); |
1da177e4 | 2105 | put_cpu(); |
476d139c NP |
2106 | if (new_cpu != this_cpu) |
2107 | sched_migrate_task(current, new_cpu); | |
1da177e4 LT |
2108 | } |
2109 | ||
2110 | /* | |
2111 | * pull_task - move a task from a remote runqueue to the local runqueue. | |
2112 | * Both runqueues must be locked. | |
2113 | */ | |
dd41f596 IM |
2114 | static void pull_task(struct rq *src_rq, struct task_struct *p, |
2115 | struct rq *this_rq, int this_cpu) | |
1da177e4 | 2116 | { |
2e1cb74a | 2117 | deactivate_task(src_rq, p, 0); |
1da177e4 | 2118 | set_task_cpu(p, this_cpu); |
dd41f596 | 2119 | activate_task(this_rq, p, 0); |
1da177e4 LT |
2120 | /* |
2121 | * Note that idle threads have a prio of MAX_PRIO, for this test | |
2122 | * to be always true for them. | |
2123 | */ | |
dd41f596 | 2124 | check_preempt_curr(this_rq, p); |
1da177e4 LT |
2125 | } |
2126 | ||
2127 | /* | |
2128 | * can_migrate_task - may task p from runqueue rq be migrated to this_cpu? | |
2129 | */ | |
858119e1 | 2130 | static |
70b97a7f | 2131 | int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu, |
d15bcfdb | 2132 | struct sched_domain *sd, enum cpu_idle_type idle, |
95cdf3b7 | 2133 | int *all_pinned) |
1da177e4 LT |
2134 | { |
2135 | /* | |
2136 | * We do not migrate tasks that are: | |
2137 | * 1) running (obviously), or | |
2138 | * 2) cannot be migrated to this CPU due to cpus_allowed, or | |
2139 | * 3) are cache-hot on their current CPU. | |
2140 | */ | |
1da177e4 LT |
2141 | if (!cpu_isset(this_cpu, p->cpus_allowed)) |
2142 | return 0; | |
81026794 NP |
2143 | *all_pinned = 0; |
2144 | ||
2145 | if (task_running(rq, p)) | |
2146 | return 0; | |
1da177e4 | 2147 | |
1da177e4 LT |
2148 | return 1; |
2149 | } | |
2150 | ||
dd41f596 | 2151 | static int balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, |
2dd73a4f | 2152 | unsigned long max_nr_move, unsigned long max_load_move, |
d15bcfdb | 2153 | struct sched_domain *sd, enum cpu_idle_type idle, |
dd41f596 | 2154 | int *all_pinned, unsigned long *load_moved, |
a4ac01c3 | 2155 | int *this_best_prio, struct rq_iterator *iterator) |
1da177e4 | 2156 | { |
dd41f596 IM |
2157 | int pulled = 0, pinned = 0, skip_for_load; |
2158 | struct task_struct *p; | |
2159 | long rem_load_move = max_load_move; | |
1da177e4 | 2160 | |
2dd73a4f | 2161 | if (max_nr_move == 0 || max_load_move == 0) |
1da177e4 LT |
2162 | goto out; |
2163 | ||
81026794 NP |
2164 | pinned = 1; |
2165 | ||
1da177e4 | 2166 | /* |
dd41f596 | 2167 | * Start the load-balancing iterator: |
1da177e4 | 2168 | */ |
dd41f596 IM |
2169 | p = iterator->start(iterator->arg); |
2170 | next: | |
2171 | if (!p) | |
1da177e4 | 2172 | goto out; |
50ddd969 PW |
2173 | /* |
2174 | * To help distribute high priority tasks accross CPUs we don't | |
2175 | * skip a task if it will be the highest priority task (i.e. smallest | |
2176 | * prio value) on its new queue regardless of its load weight | |
2177 | */ | |
dd41f596 IM |
2178 | skip_for_load = (p->se.load.weight >> 1) > rem_load_move + |
2179 | SCHED_LOAD_SCALE_FUZZ; | |
a4ac01c3 | 2180 | if ((skip_for_load && p->prio >= *this_best_prio) || |
dd41f596 | 2181 | !can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) { |
dd41f596 IM |
2182 | p = iterator->next(iterator->arg); |
2183 | goto next; | |
1da177e4 LT |
2184 | } |
2185 | ||
dd41f596 | 2186 | pull_task(busiest, p, this_rq, this_cpu); |
1da177e4 | 2187 | pulled++; |
dd41f596 | 2188 | rem_load_move -= p->se.load.weight; |
1da177e4 | 2189 | |
2dd73a4f PW |
2190 | /* |
2191 | * We only want to steal up to the prescribed number of tasks | |
2192 | * and the prescribed amount of weighted load. | |
2193 | */ | |
2194 | if (pulled < max_nr_move && rem_load_move > 0) { | |
a4ac01c3 PW |
2195 | if (p->prio < *this_best_prio) |
2196 | *this_best_prio = p->prio; | |
dd41f596 IM |
2197 | p = iterator->next(iterator->arg); |
2198 | goto next; | |
1da177e4 LT |
2199 | } |
2200 | out: | |
2201 | /* | |
2202 | * Right now, this is the only place pull_task() is called, | |
2203 | * so we can safely collect pull_task() stats here rather than | |
2204 | * inside pull_task(). | |
2205 | */ | |
2206 | schedstat_add(sd, lb_gained[idle], pulled); | |
81026794 NP |
2207 | |
2208 | if (all_pinned) | |
2209 | *all_pinned = pinned; | |
dd41f596 | 2210 | *load_moved = max_load_move - rem_load_move; |
1da177e4 LT |
2211 | return pulled; |
2212 | } | |
2213 | ||
dd41f596 | 2214 | /* |
43010659 PW |
2215 | * move_tasks tries to move up to max_load_move weighted load from busiest to |
2216 | * this_rq, as part of a balancing operation within domain "sd". | |
2217 | * Returns 1 if successful and 0 otherwise. | |
dd41f596 IM |
2218 | * |
2219 | * Called with both runqueues locked. | |
2220 | */ | |
2221 | static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
43010659 | 2222 | unsigned long max_load_move, |
dd41f596 IM |
2223 | struct sched_domain *sd, enum cpu_idle_type idle, |
2224 | int *all_pinned) | |
2225 | { | |
5522d5d5 | 2226 | const struct sched_class *class = sched_class_highest; |
43010659 | 2227 | unsigned long total_load_moved = 0; |
a4ac01c3 | 2228 | int this_best_prio = this_rq->curr->prio; |
dd41f596 IM |
2229 | |
2230 | do { | |
43010659 PW |
2231 | total_load_moved += |
2232 | class->load_balance(this_rq, this_cpu, busiest, | |
2233 | ULONG_MAX, max_load_move - total_load_moved, | |
a4ac01c3 | 2234 | sd, idle, all_pinned, &this_best_prio); |
dd41f596 | 2235 | class = class->next; |
43010659 | 2236 | } while (class && max_load_move > total_load_moved); |
dd41f596 | 2237 | |
43010659 PW |
2238 | return total_load_moved > 0; |
2239 | } | |
2240 | ||
2241 | /* | |
2242 | * move_one_task tries to move exactly one task from busiest to this_rq, as | |
2243 | * part of active balancing operations within "domain". | |
2244 | * Returns 1 if successful and 0 otherwise. | |
2245 | * | |
2246 | * Called with both runqueues locked. | |
2247 | */ | |
2248 | static int move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
2249 | struct sched_domain *sd, enum cpu_idle_type idle) | |
2250 | { | |
5522d5d5 | 2251 | const struct sched_class *class; |
a4ac01c3 | 2252 | int this_best_prio = MAX_PRIO; |
43010659 PW |
2253 | |
2254 | for (class = sched_class_highest; class; class = class->next) | |
2255 | if (class->load_balance(this_rq, this_cpu, busiest, | |
a4ac01c3 PW |
2256 | 1, ULONG_MAX, sd, idle, NULL, |
2257 | &this_best_prio)) | |
43010659 PW |
2258 | return 1; |
2259 | ||
2260 | return 0; | |
dd41f596 IM |
2261 | } |
2262 | ||
1da177e4 LT |
2263 | /* |
2264 | * find_busiest_group finds and returns the busiest CPU group within the | |
48f24c4d IM |
2265 | * domain. It calculates and returns the amount of weighted load which |
2266 | * should be moved to restore balance via the imbalance parameter. | |
1da177e4 LT |
2267 | */ |
2268 | static struct sched_group * | |
2269 | find_busiest_group(struct sched_domain *sd, int this_cpu, | |
dd41f596 IM |
2270 | unsigned long *imbalance, enum cpu_idle_type idle, |
2271 | int *sd_idle, cpumask_t *cpus, int *balance) | |
1da177e4 LT |
2272 | { |
2273 | struct sched_group *busiest = NULL, *this = NULL, *group = sd->groups; | |
2274 | unsigned long max_load, avg_load, total_load, this_load, total_pwr; | |
0c117f1b | 2275 | unsigned long max_pull; |
2dd73a4f PW |
2276 | unsigned long busiest_load_per_task, busiest_nr_running; |
2277 | unsigned long this_load_per_task, this_nr_running; | |
7897986b | 2278 | int load_idx; |
5c45bf27 SS |
2279 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) |
2280 | int power_savings_balance = 1; | |
2281 | unsigned long leader_nr_running = 0, min_load_per_task = 0; | |
2282 | unsigned long min_nr_running = ULONG_MAX; | |
2283 | struct sched_group *group_min = NULL, *group_leader = NULL; | |
2284 | #endif | |
1da177e4 LT |
2285 | |
2286 | max_load = this_load = total_load = total_pwr = 0; | |
2dd73a4f PW |
2287 | busiest_load_per_task = busiest_nr_running = 0; |
2288 | this_load_per_task = this_nr_running = 0; | |
d15bcfdb | 2289 | if (idle == CPU_NOT_IDLE) |
7897986b | 2290 | load_idx = sd->busy_idx; |
d15bcfdb | 2291 | else if (idle == CPU_NEWLY_IDLE) |
7897986b NP |
2292 | load_idx = sd->newidle_idx; |
2293 | else | |
2294 | load_idx = sd->idle_idx; | |
1da177e4 LT |
2295 | |
2296 | do { | |
5c45bf27 | 2297 | unsigned long load, group_capacity; |
1da177e4 LT |
2298 | int local_group; |
2299 | int i; | |
783609c6 | 2300 | unsigned int balance_cpu = -1, first_idle_cpu = 0; |
2dd73a4f | 2301 | unsigned long sum_nr_running, sum_weighted_load; |
1da177e4 LT |
2302 | |
2303 | local_group = cpu_isset(this_cpu, group->cpumask); | |
2304 | ||
783609c6 SS |
2305 | if (local_group) |
2306 | balance_cpu = first_cpu(group->cpumask); | |
2307 | ||
1da177e4 | 2308 | /* Tally up the load of all CPUs in the group */ |
2dd73a4f | 2309 | sum_weighted_load = sum_nr_running = avg_load = 0; |
1da177e4 LT |
2310 | |
2311 | for_each_cpu_mask(i, group->cpumask) { | |
0a2966b4 CL |
2312 | struct rq *rq; |
2313 | ||
2314 | if (!cpu_isset(i, *cpus)) | |
2315 | continue; | |
2316 | ||
2317 | rq = cpu_rq(i); | |
2dd73a4f | 2318 | |
9439aab8 | 2319 | if (*sd_idle && rq->nr_running) |
5969fe06 NP |
2320 | *sd_idle = 0; |
2321 | ||
1da177e4 | 2322 | /* Bias balancing toward cpus of our domain */ |
783609c6 SS |
2323 | if (local_group) { |
2324 | if (idle_cpu(i) && !first_idle_cpu) { | |
2325 | first_idle_cpu = 1; | |
2326 | balance_cpu = i; | |
2327 | } | |
2328 | ||
a2000572 | 2329 | load = target_load(i, load_idx); |
783609c6 | 2330 | } else |
a2000572 | 2331 | load = source_load(i, load_idx); |
1da177e4 LT |
2332 | |
2333 | avg_load += load; | |
2dd73a4f | 2334 | sum_nr_running += rq->nr_running; |
dd41f596 | 2335 | sum_weighted_load += weighted_cpuload(i); |
1da177e4 LT |
2336 | } |
2337 | ||
783609c6 SS |
2338 | /* |
2339 | * First idle cpu or the first cpu(busiest) in this sched group | |
2340 | * is eligible for doing load balancing at this and above | |
9439aab8 SS |
2341 | * domains. In the newly idle case, we will allow all the cpu's |
2342 | * to do the newly idle load balance. | |
783609c6 | 2343 | */ |
9439aab8 SS |
2344 | if (idle != CPU_NEWLY_IDLE && local_group && |
2345 | balance_cpu != this_cpu && balance) { | |
783609c6 SS |
2346 | *balance = 0; |
2347 | goto ret; | |
2348 | } | |
2349 | ||
1da177e4 | 2350 | total_load += avg_load; |
5517d86b | 2351 | total_pwr += group->__cpu_power; |
1da177e4 LT |
2352 | |
2353 | /* Adjust by relative CPU power of the group */ | |
5517d86b ED |
2354 | avg_load = sg_div_cpu_power(group, |
2355 | avg_load * SCHED_LOAD_SCALE); | |
1da177e4 | 2356 | |
5517d86b | 2357 | group_capacity = group->__cpu_power / SCHED_LOAD_SCALE; |
5c45bf27 | 2358 | |
1da177e4 LT |
2359 | if (local_group) { |
2360 | this_load = avg_load; | |
2361 | this = group; | |
2dd73a4f PW |
2362 | this_nr_running = sum_nr_running; |
2363 | this_load_per_task = sum_weighted_load; | |
2364 | } else if (avg_load > max_load && | |
5c45bf27 | 2365 | sum_nr_running > group_capacity) { |
1da177e4 LT |
2366 | max_load = avg_load; |
2367 | busiest = group; | |
2dd73a4f PW |
2368 | busiest_nr_running = sum_nr_running; |
2369 | busiest_load_per_task = sum_weighted_load; | |
1da177e4 | 2370 | } |
5c45bf27 SS |
2371 | |
2372 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) | |
2373 | /* | |
2374 | * Busy processors will not participate in power savings | |
2375 | * balance. | |
2376 | */ | |
dd41f596 IM |
2377 | if (idle == CPU_NOT_IDLE || |
2378 | !(sd->flags & SD_POWERSAVINGS_BALANCE)) | |
2379 | goto group_next; | |
5c45bf27 SS |
2380 | |
2381 | /* | |
2382 | * If the local group is idle or completely loaded | |
2383 | * no need to do power savings balance at this domain | |
2384 | */ | |
2385 | if (local_group && (this_nr_running >= group_capacity || | |
2386 | !this_nr_running)) | |
2387 | power_savings_balance = 0; | |
2388 | ||
dd41f596 | 2389 | /* |
5c45bf27 SS |
2390 | * If a group is already running at full capacity or idle, |
2391 | * don't include that group in power savings calculations | |
dd41f596 IM |
2392 | */ |
2393 | if (!power_savings_balance || sum_nr_running >= group_capacity | |
5c45bf27 | 2394 | || !sum_nr_running) |
dd41f596 | 2395 | goto group_next; |
5c45bf27 | 2396 | |
dd41f596 | 2397 | /* |
5c45bf27 | 2398 | * Calculate the group which has the least non-idle load. |
dd41f596 IM |
2399 | * This is the group from where we need to pick up the load |
2400 | * for saving power | |
2401 | */ | |
2402 | if ((sum_nr_running < min_nr_running) || | |
2403 | (sum_nr_running == min_nr_running && | |
5c45bf27 SS |
2404 | first_cpu(group->cpumask) < |
2405 | first_cpu(group_min->cpumask))) { | |
dd41f596 IM |
2406 | group_min = group; |
2407 | min_nr_running = sum_nr_running; | |
5c45bf27 SS |
2408 | min_load_per_task = sum_weighted_load / |
2409 | sum_nr_running; | |
dd41f596 | 2410 | } |
5c45bf27 | 2411 | |
dd41f596 | 2412 | /* |
5c45bf27 | 2413 | * Calculate the group which is almost near its |
dd41f596 IM |
2414 | * capacity but still has some space to pick up some load |
2415 | * from other group and save more power | |
2416 | */ | |
2417 | if (sum_nr_running <= group_capacity - 1) { | |
2418 | if (sum_nr_running > leader_nr_running || | |
2419 | (sum_nr_running == leader_nr_running && | |
2420 | first_cpu(group->cpumask) > | |
2421 | first_cpu(group_leader->cpumask))) { | |
2422 | group_leader = group; | |
2423 | leader_nr_running = sum_nr_running; | |
2424 | } | |
48f24c4d | 2425 | } |
5c45bf27 SS |
2426 | group_next: |
2427 | #endif | |
1da177e4 LT |
2428 | group = group->next; |
2429 | } while (group != sd->groups); | |
2430 | ||
2dd73a4f | 2431 | if (!busiest || this_load >= max_load || busiest_nr_running == 0) |
1da177e4 LT |
2432 | goto out_balanced; |
2433 | ||
2434 | avg_load = (SCHED_LOAD_SCALE * total_load) / total_pwr; | |
2435 | ||
2436 | if (this_load >= avg_load || | |
2437 | 100*max_load <= sd->imbalance_pct*this_load) | |
2438 | goto out_balanced; | |
2439 | ||
2dd73a4f | 2440 | busiest_load_per_task /= busiest_nr_running; |
1da177e4 LT |
2441 | /* |
2442 | * We're trying to get all the cpus to the average_load, so we don't | |
2443 | * want to push ourselves above the average load, nor do we wish to | |
2444 | * reduce the max loaded cpu below the average load, as either of these | |
2445 | * actions would just result in more rebalancing later, and ping-pong | |
2446 | * tasks around. Thus we look for the minimum possible imbalance. | |
2447 | * Negative imbalances (*we* are more loaded than anyone else) will | |
2448 | * be counted as no imbalance for these purposes -- we can't fix that | |
2449 | * by pulling tasks to us. Be careful of negative numbers as they'll | |
2450 | * appear as very large values with unsigned longs. | |
2451 | */ | |
2dd73a4f PW |
2452 | if (max_load <= busiest_load_per_task) |
2453 | goto out_balanced; | |
2454 | ||
2455 | /* | |
2456 | * In the presence of smp nice balancing, certain scenarios can have | |
2457 | * max load less than avg load(as we skip the groups at or below | |
2458 | * its cpu_power, while calculating max_load..) | |
2459 | */ | |
2460 | if (max_load < avg_load) { | |
2461 | *imbalance = 0; | |
2462 | goto small_imbalance; | |
2463 | } | |
0c117f1b SS |
2464 | |
2465 | /* Don't want to pull so many tasks that a group would go idle */ | |
2dd73a4f | 2466 | max_pull = min(max_load - avg_load, max_load - busiest_load_per_task); |
0c117f1b | 2467 | |
1da177e4 | 2468 | /* How much load to actually move to equalise the imbalance */ |
5517d86b ED |
2469 | *imbalance = min(max_pull * busiest->__cpu_power, |
2470 | (avg_load - this_load) * this->__cpu_power) | |
1da177e4 LT |
2471 | / SCHED_LOAD_SCALE; |
2472 | ||
2dd73a4f PW |
2473 | /* |
2474 | * if *imbalance is less than the average load per runnable task | |
2475 | * there is no gaurantee that any tasks will be moved so we'll have | |
2476 | * a think about bumping its value to force at least one task to be | |
2477 | * moved | |
2478 | */ | |
7fd0d2dd | 2479 | if (*imbalance < busiest_load_per_task) { |
48f24c4d | 2480 | unsigned long tmp, pwr_now, pwr_move; |
2dd73a4f PW |
2481 | unsigned int imbn; |
2482 | ||
2483 | small_imbalance: | |
2484 | pwr_move = pwr_now = 0; | |
2485 | imbn = 2; | |
2486 | if (this_nr_running) { | |
2487 | this_load_per_task /= this_nr_running; | |
2488 | if (busiest_load_per_task > this_load_per_task) | |
2489 | imbn = 1; | |
2490 | } else | |
2491 | this_load_per_task = SCHED_LOAD_SCALE; | |
1da177e4 | 2492 | |
dd41f596 IM |
2493 | if (max_load - this_load + SCHED_LOAD_SCALE_FUZZ >= |
2494 | busiest_load_per_task * imbn) { | |
2dd73a4f | 2495 | *imbalance = busiest_load_per_task; |
1da177e4 LT |
2496 | return busiest; |
2497 | } | |
2498 | ||
2499 | /* | |
2500 | * OK, we don't have enough imbalance to justify moving tasks, | |
2501 | * however we may be able to increase total CPU power used by | |
2502 | * moving them. | |
2503 | */ | |
2504 | ||
5517d86b ED |
2505 | pwr_now += busiest->__cpu_power * |
2506 | min(busiest_load_per_task, max_load); | |
2507 | pwr_now += this->__cpu_power * | |
2508 | min(this_load_per_task, this_load); | |
1da177e4 LT |
2509 | pwr_now /= SCHED_LOAD_SCALE; |
2510 | ||
2511 | /* Amount of load we'd subtract */ | |
5517d86b ED |
2512 | tmp = sg_div_cpu_power(busiest, |
2513 | busiest_load_per_task * SCHED_LOAD_SCALE); | |
1da177e4 | 2514 | if (max_load > tmp) |
5517d86b | 2515 | pwr_move += busiest->__cpu_power * |
2dd73a4f | 2516 | min(busiest_load_per_task, max_load - tmp); |
1da177e4 LT |
2517 | |
2518 | /* Amount of load we'd add */ | |
5517d86b | 2519 | if (max_load * busiest->__cpu_power < |
33859f7f | 2520 | busiest_load_per_task * SCHED_LOAD_SCALE) |
5517d86b ED |
2521 | tmp = sg_div_cpu_power(this, |
2522 | max_load * busiest->__cpu_power); | |
1da177e4 | 2523 | else |
5517d86b ED |
2524 | tmp = sg_div_cpu_power(this, |
2525 | busiest_load_per_task * SCHED_LOAD_SCALE); | |
2526 | pwr_move += this->__cpu_power * | |
2527 | min(this_load_per_task, this_load + tmp); | |
1da177e4 LT |
2528 | pwr_move /= SCHED_LOAD_SCALE; |
2529 | ||
2530 | /* Move if we gain throughput */ | |
7fd0d2dd SS |
2531 | if (pwr_move > pwr_now) |
2532 | *imbalance = busiest_load_per_task; | |
1da177e4 LT |
2533 | } |
2534 | ||
1da177e4 LT |
2535 | return busiest; |
2536 | ||
2537 | out_balanced: | |
5c45bf27 | 2538 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) |
d15bcfdb | 2539 | if (idle == CPU_NOT_IDLE || !(sd->flags & SD_POWERSAVINGS_BALANCE)) |
5c45bf27 | 2540 | goto ret; |
1da177e4 | 2541 | |
5c45bf27 SS |
2542 | if (this == group_leader && group_leader != group_min) { |
2543 | *imbalance = min_load_per_task; | |
2544 | return group_min; | |
2545 | } | |
5c45bf27 | 2546 | #endif |
783609c6 | 2547 | ret: |
1da177e4 LT |
2548 | *imbalance = 0; |
2549 | return NULL; | |
2550 | } | |
2551 | ||
2552 | /* | |
2553 | * find_busiest_queue - find the busiest runqueue among the cpus in group. | |
2554 | */ | |
70b97a7f | 2555 | static struct rq * |
d15bcfdb | 2556 | find_busiest_queue(struct sched_group *group, enum cpu_idle_type idle, |
0a2966b4 | 2557 | unsigned long imbalance, cpumask_t *cpus) |
1da177e4 | 2558 | { |
70b97a7f | 2559 | struct rq *busiest = NULL, *rq; |
2dd73a4f | 2560 | unsigned long max_load = 0; |
1da177e4 LT |
2561 | int i; |
2562 | ||
2563 | for_each_cpu_mask(i, group->cpumask) { | |
dd41f596 | 2564 | unsigned long wl; |
0a2966b4 CL |
2565 | |
2566 | if (!cpu_isset(i, *cpus)) | |
2567 | continue; | |
2568 | ||
48f24c4d | 2569 | rq = cpu_rq(i); |
dd41f596 | 2570 | wl = weighted_cpuload(i); |
2dd73a4f | 2571 | |
dd41f596 | 2572 | if (rq->nr_running == 1 && wl > imbalance) |
2dd73a4f | 2573 | continue; |
1da177e4 | 2574 | |
dd41f596 IM |
2575 | if (wl > max_load) { |
2576 | max_load = wl; | |
48f24c4d | 2577 | busiest = rq; |
1da177e4 LT |
2578 | } |
2579 | } | |
2580 | ||
2581 | return busiest; | |
2582 | } | |
2583 | ||
77391d71 NP |
2584 | /* |
2585 | * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but | |
2586 | * so long as it is large enough. | |
2587 | */ | |
2588 | #define MAX_PINNED_INTERVAL 512 | |
2589 | ||
1da177e4 LT |
2590 | /* |
2591 | * Check this_cpu to ensure it is balanced within domain. Attempt to move | |
2592 | * tasks if there is an imbalance. | |
1da177e4 | 2593 | */ |
70b97a7f | 2594 | static int load_balance(int this_cpu, struct rq *this_rq, |
d15bcfdb | 2595 | struct sched_domain *sd, enum cpu_idle_type idle, |
783609c6 | 2596 | int *balance) |
1da177e4 | 2597 | { |
43010659 | 2598 | int ld_moved, all_pinned = 0, active_balance = 0, sd_idle = 0; |
1da177e4 | 2599 | struct sched_group *group; |
1da177e4 | 2600 | unsigned long imbalance; |
70b97a7f | 2601 | struct rq *busiest; |
0a2966b4 | 2602 | cpumask_t cpus = CPU_MASK_ALL; |
fe2eea3f | 2603 | unsigned long flags; |
5969fe06 | 2604 | |
89c4710e SS |
2605 | /* |
2606 | * When power savings policy is enabled for the parent domain, idle | |
2607 | * sibling can pick up load irrespective of busy siblings. In this case, | |
dd41f596 | 2608 | * let the state of idle sibling percolate up as CPU_IDLE, instead of |
d15bcfdb | 2609 | * portraying it as CPU_NOT_IDLE. |
89c4710e | 2610 | */ |
d15bcfdb | 2611 | if (idle != CPU_NOT_IDLE && sd->flags & SD_SHARE_CPUPOWER && |
89c4710e | 2612 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
5969fe06 | 2613 | sd_idle = 1; |
1da177e4 | 2614 | |
2d72376b | 2615 | schedstat_inc(sd, lb_count[idle]); |
1da177e4 | 2616 | |
0a2966b4 CL |
2617 | redo: |
2618 | group = find_busiest_group(sd, this_cpu, &imbalance, idle, &sd_idle, | |
783609c6 SS |
2619 | &cpus, balance); |
2620 | ||
06066714 | 2621 | if (*balance == 0) |
783609c6 | 2622 | goto out_balanced; |
783609c6 | 2623 | |
1da177e4 LT |
2624 | if (!group) { |
2625 | schedstat_inc(sd, lb_nobusyg[idle]); | |
2626 | goto out_balanced; | |
2627 | } | |
2628 | ||
0a2966b4 | 2629 | busiest = find_busiest_queue(group, idle, imbalance, &cpus); |
1da177e4 LT |
2630 | if (!busiest) { |
2631 | schedstat_inc(sd, lb_nobusyq[idle]); | |
2632 | goto out_balanced; | |
2633 | } | |
2634 | ||
db935dbd | 2635 | BUG_ON(busiest == this_rq); |
1da177e4 LT |
2636 | |
2637 | schedstat_add(sd, lb_imbalance[idle], imbalance); | |
2638 | ||
43010659 | 2639 | ld_moved = 0; |
1da177e4 LT |
2640 | if (busiest->nr_running > 1) { |
2641 | /* | |
2642 | * Attempt to move tasks. If find_busiest_group has found | |
2643 | * an imbalance but busiest->nr_running <= 1, the group is | |
43010659 | 2644 | * still unbalanced. ld_moved simply stays zero, so it is |
1da177e4 LT |
2645 | * correctly treated as an imbalance. |
2646 | */ | |
fe2eea3f | 2647 | local_irq_save(flags); |
e17224bf | 2648 | double_rq_lock(this_rq, busiest); |
43010659 | 2649 | ld_moved = move_tasks(this_rq, this_cpu, busiest, |
48f24c4d | 2650 | imbalance, sd, idle, &all_pinned); |
e17224bf | 2651 | double_rq_unlock(this_rq, busiest); |
fe2eea3f | 2652 | local_irq_restore(flags); |
81026794 | 2653 | |
46cb4b7c SS |
2654 | /* |
2655 | * some other cpu did the load balance for us. | |
2656 | */ | |
43010659 | 2657 | if (ld_moved && this_cpu != smp_processor_id()) |
46cb4b7c SS |
2658 | resched_cpu(this_cpu); |
2659 | ||
81026794 | 2660 | /* All tasks on this runqueue were pinned by CPU affinity */ |
0a2966b4 CL |
2661 | if (unlikely(all_pinned)) { |
2662 | cpu_clear(cpu_of(busiest), cpus); | |
2663 | if (!cpus_empty(cpus)) | |
2664 | goto redo; | |
81026794 | 2665 | goto out_balanced; |
0a2966b4 | 2666 | } |
1da177e4 | 2667 | } |
81026794 | 2668 | |
43010659 | 2669 | if (!ld_moved) { |
1da177e4 LT |
2670 | schedstat_inc(sd, lb_failed[idle]); |
2671 | sd->nr_balance_failed++; | |
2672 | ||
2673 | if (unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2)) { | |
1da177e4 | 2674 | |
fe2eea3f | 2675 | spin_lock_irqsave(&busiest->lock, flags); |
fa3b6ddc SS |
2676 | |
2677 | /* don't kick the migration_thread, if the curr | |
2678 | * task on busiest cpu can't be moved to this_cpu | |
2679 | */ | |
2680 | if (!cpu_isset(this_cpu, busiest->curr->cpus_allowed)) { | |
fe2eea3f | 2681 | spin_unlock_irqrestore(&busiest->lock, flags); |
fa3b6ddc SS |
2682 | all_pinned = 1; |
2683 | goto out_one_pinned; | |
2684 | } | |
2685 | ||
1da177e4 LT |
2686 | if (!busiest->active_balance) { |
2687 | busiest->active_balance = 1; | |
2688 | busiest->push_cpu = this_cpu; | |
81026794 | 2689 | active_balance = 1; |
1da177e4 | 2690 | } |
fe2eea3f | 2691 | spin_unlock_irqrestore(&busiest->lock, flags); |
81026794 | 2692 | if (active_balance) |
1da177e4 LT |
2693 | wake_up_process(busiest->migration_thread); |
2694 | ||
2695 | /* | |
2696 | * We've kicked active balancing, reset the failure | |
2697 | * counter. | |
2698 | */ | |
39507451 | 2699 | sd->nr_balance_failed = sd->cache_nice_tries+1; |
1da177e4 | 2700 | } |
81026794 | 2701 | } else |
1da177e4 LT |
2702 | sd->nr_balance_failed = 0; |
2703 | ||
81026794 | 2704 | if (likely(!active_balance)) { |
1da177e4 LT |
2705 | /* We were unbalanced, so reset the balancing interval */ |
2706 | sd->balance_interval = sd->min_interval; | |
81026794 NP |
2707 | } else { |
2708 | /* | |
2709 | * If we've begun active balancing, start to back off. This | |
2710 | * case may not be covered by the all_pinned logic if there | |
2711 | * is only 1 task on the busy runqueue (because we don't call | |
2712 | * move_tasks). | |
2713 | */ | |
2714 | if (sd->balance_interval < sd->max_interval) | |
2715 | sd->balance_interval *= 2; | |
1da177e4 LT |
2716 | } |
2717 | ||
43010659 | 2718 | if (!ld_moved && !sd_idle && sd->flags & SD_SHARE_CPUPOWER && |
89c4710e | 2719 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
5969fe06 | 2720 | return -1; |
43010659 | 2721 | return ld_moved; |
1da177e4 LT |
2722 | |
2723 | out_balanced: | |
1da177e4 LT |
2724 | schedstat_inc(sd, lb_balanced[idle]); |
2725 | ||
16cfb1c0 | 2726 | sd->nr_balance_failed = 0; |
fa3b6ddc SS |
2727 | |
2728 | out_one_pinned: | |
1da177e4 | 2729 | /* tune up the balancing interval */ |
77391d71 NP |
2730 | if ((all_pinned && sd->balance_interval < MAX_PINNED_INTERVAL) || |
2731 | (sd->balance_interval < sd->max_interval)) | |
1da177e4 LT |
2732 | sd->balance_interval *= 2; |
2733 | ||
48f24c4d | 2734 | if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && |
89c4710e | 2735 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
5969fe06 | 2736 | return -1; |
1da177e4 LT |
2737 | return 0; |
2738 | } | |
2739 | ||
2740 | /* | |
2741 | * Check this_cpu to ensure it is balanced within domain. Attempt to move | |
2742 | * tasks if there is an imbalance. | |
2743 | * | |
d15bcfdb | 2744 | * Called from schedule when this_rq is about to become idle (CPU_NEWLY_IDLE). |
1da177e4 LT |
2745 | * this_rq is locked. |
2746 | */ | |
48f24c4d | 2747 | static int |
70b97a7f | 2748 | load_balance_newidle(int this_cpu, struct rq *this_rq, struct sched_domain *sd) |
1da177e4 LT |
2749 | { |
2750 | struct sched_group *group; | |
70b97a7f | 2751 | struct rq *busiest = NULL; |
1da177e4 | 2752 | unsigned long imbalance; |
43010659 | 2753 | int ld_moved = 0; |
5969fe06 | 2754 | int sd_idle = 0; |
969bb4e4 | 2755 | int all_pinned = 0; |
0a2966b4 | 2756 | cpumask_t cpus = CPU_MASK_ALL; |
5969fe06 | 2757 | |
89c4710e SS |
2758 | /* |
2759 | * When power savings policy is enabled for the parent domain, idle | |
2760 | * sibling can pick up load irrespective of busy siblings. In this case, | |
2761 | * let the state of idle sibling percolate up as IDLE, instead of | |
d15bcfdb | 2762 | * portraying it as CPU_NOT_IDLE. |
89c4710e SS |
2763 | */ |
2764 | if (sd->flags & SD_SHARE_CPUPOWER && | |
2765 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) | |
5969fe06 | 2766 | sd_idle = 1; |
1da177e4 | 2767 | |
2d72376b | 2768 | schedstat_inc(sd, lb_count[CPU_NEWLY_IDLE]); |
0a2966b4 | 2769 | redo: |
d15bcfdb | 2770 | group = find_busiest_group(sd, this_cpu, &imbalance, CPU_NEWLY_IDLE, |
783609c6 | 2771 | &sd_idle, &cpus, NULL); |
1da177e4 | 2772 | if (!group) { |
d15bcfdb | 2773 | schedstat_inc(sd, lb_nobusyg[CPU_NEWLY_IDLE]); |
16cfb1c0 | 2774 | goto out_balanced; |
1da177e4 LT |
2775 | } |
2776 | ||
d15bcfdb | 2777 | busiest = find_busiest_queue(group, CPU_NEWLY_IDLE, imbalance, |
0a2966b4 | 2778 | &cpus); |
db935dbd | 2779 | if (!busiest) { |
d15bcfdb | 2780 | schedstat_inc(sd, lb_nobusyq[CPU_NEWLY_IDLE]); |
16cfb1c0 | 2781 | goto out_balanced; |
1da177e4 LT |
2782 | } |
2783 | ||
db935dbd NP |
2784 | BUG_ON(busiest == this_rq); |
2785 | ||
d15bcfdb | 2786 | schedstat_add(sd, lb_imbalance[CPU_NEWLY_IDLE], imbalance); |
d6d5cfaf | 2787 | |
43010659 | 2788 | ld_moved = 0; |
d6d5cfaf NP |
2789 | if (busiest->nr_running > 1) { |
2790 | /* Attempt to move tasks */ | |
2791 | double_lock_balance(this_rq, busiest); | |
6e82a3be IM |
2792 | /* this_rq->clock is already updated */ |
2793 | update_rq_clock(busiest); | |
43010659 | 2794 | ld_moved = move_tasks(this_rq, this_cpu, busiest, |
969bb4e4 SS |
2795 | imbalance, sd, CPU_NEWLY_IDLE, |
2796 | &all_pinned); | |
d6d5cfaf | 2797 | spin_unlock(&busiest->lock); |
0a2966b4 | 2798 | |
969bb4e4 | 2799 | if (unlikely(all_pinned)) { |
0a2966b4 CL |
2800 | cpu_clear(cpu_of(busiest), cpus); |
2801 | if (!cpus_empty(cpus)) | |
2802 | goto redo; | |
2803 | } | |
d6d5cfaf NP |
2804 | } |
2805 | ||
43010659 | 2806 | if (!ld_moved) { |
d15bcfdb | 2807 | schedstat_inc(sd, lb_failed[CPU_NEWLY_IDLE]); |
89c4710e SS |
2808 | if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && |
2809 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) | |
5969fe06 NP |
2810 | return -1; |
2811 | } else | |
16cfb1c0 | 2812 | sd->nr_balance_failed = 0; |
1da177e4 | 2813 | |
43010659 | 2814 | return ld_moved; |
16cfb1c0 NP |
2815 | |
2816 | out_balanced: | |
d15bcfdb | 2817 | schedstat_inc(sd, lb_balanced[CPU_NEWLY_IDLE]); |
48f24c4d | 2818 | if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && |
89c4710e | 2819 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
5969fe06 | 2820 | return -1; |
16cfb1c0 | 2821 | sd->nr_balance_failed = 0; |
48f24c4d | 2822 | |
16cfb1c0 | 2823 | return 0; |
1da177e4 LT |
2824 | } |
2825 | ||
2826 | /* | |
2827 | * idle_balance is called by schedule() if this_cpu is about to become | |
2828 | * idle. Attempts to pull tasks from other CPUs. | |
2829 | */ | |
70b97a7f | 2830 | static void idle_balance(int this_cpu, struct rq *this_rq) |
1da177e4 LT |
2831 | { |
2832 | struct sched_domain *sd; | |
dd41f596 IM |
2833 | int pulled_task = -1; |
2834 | unsigned long next_balance = jiffies + HZ; | |
1da177e4 LT |
2835 | |
2836 | for_each_domain(this_cpu, sd) { | |
92c4ca5c CL |
2837 | unsigned long interval; |
2838 | ||
2839 | if (!(sd->flags & SD_LOAD_BALANCE)) | |
2840 | continue; | |
2841 | ||
2842 | if (sd->flags & SD_BALANCE_NEWIDLE) | |
48f24c4d | 2843 | /* If we've pulled tasks over stop searching: */ |
1bd77f2d | 2844 | pulled_task = load_balance_newidle(this_cpu, |
92c4ca5c CL |
2845 | this_rq, sd); |
2846 | ||
2847 | interval = msecs_to_jiffies(sd->balance_interval); | |
2848 | if (time_after(next_balance, sd->last_balance + interval)) | |
2849 | next_balance = sd->last_balance + interval; | |
2850 | if (pulled_task) | |
2851 | break; | |
1da177e4 | 2852 | } |
dd41f596 | 2853 | if (pulled_task || time_after(jiffies, this_rq->next_balance)) { |
1bd77f2d CL |
2854 | /* |
2855 | * We are going idle. next_balance may be set based on | |
2856 | * a busy processor. So reset next_balance. | |
2857 | */ | |
2858 | this_rq->next_balance = next_balance; | |
dd41f596 | 2859 | } |
1da177e4 LT |
2860 | } |
2861 | ||
2862 | /* | |
2863 | * active_load_balance is run by migration threads. It pushes running tasks | |
2864 | * off the busiest CPU onto idle CPUs. It requires at least 1 task to be | |
2865 | * running on each physical CPU where possible, and avoids physical / | |
2866 | * logical imbalances. | |
2867 | * | |
2868 | * Called with busiest_rq locked. | |
2869 | */ | |
70b97a7f | 2870 | static void active_load_balance(struct rq *busiest_rq, int busiest_cpu) |
1da177e4 | 2871 | { |
39507451 | 2872 | int target_cpu = busiest_rq->push_cpu; |
70b97a7f IM |
2873 | struct sched_domain *sd; |
2874 | struct rq *target_rq; | |
39507451 | 2875 | |
48f24c4d | 2876 | /* Is there any task to move? */ |
39507451 | 2877 | if (busiest_rq->nr_running <= 1) |
39507451 NP |
2878 | return; |
2879 | ||
2880 | target_rq = cpu_rq(target_cpu); | |
1da177e4 LT |
2881 | |
2882 | /* | |
39507451 NP |
2883 | * This condition is "impossible", if it occurs |
2884 | * we need to fix it. Originally reported by | |
2885 | * Bjorn Helgaas on a 128-cpu setup. | |
1da177e4 | 2886 | */ |
39507451 | 2887 | BUG_ON(busiest_rq == target_rq); |
1da177e4 | 2888 | |
39507451 NP |
2889 | /* move a task from busiest_rq to target_rq */ |
2890 | double_lock_balance(busiest_rq, target_rq); | |
6e82a3be IM |
2891 | update_rq_clock(busiest_rq); |
2892 | update_rq_clock(target_rq); | |
39507451 NP |
2893 | |
2894 | /* Search for an sd spanning us and the target CPU. */ | |
c96d145e | 2895 | for_each_domain(target_cpu, sd) { |
39507451 | 2896 | if ((sd->flags & SD_LOAD_BALANCE) && |
48f24c4d | 2897 | cpu_isset(busiest_cpu, sd->span)) |
39507451 | 2898 | break; |
c96d145e | 2899 | } |
39507451 | 2900 | |
48f24c4d | 2901 | if (likely(sd)) { |
2d72376b | 2902 | schedstat_inc(sd, alb_count); |
39507451 | 2903 | |
43010659 PW |
2904 | if (move_one_task(target_rq, target_cpu, busiest_rq, |
2905 | sd, CPU_IDLE)) | |
48f24c4d IM |
2906 | schedstat_inc(sd, alb_pushed); |
2907 | else | |
2908 | schedstat_inc(sd, alb_failed); | |
2909 | } | |
39507451 | 2910 | spin_unlock(&target_rq->lock); |
1da177e4 LT |
2911 | } |
2912 | ||
46cb4b7c SS |
2913 | #ifdef CONFIG_NO_HZ |
2914 | static struct { | |
2915 | atomic_t load_balancer; | |
2916 | cpumask_t cpu_mask; | |
2917 | } nohz ____cacheline_aligned = { | |
2918 | .load_balancer = ATOMIC_INIT(-1), | |
2919 | .cpu_mask = CPU_MASK_NONE, | |
2920 | }; | |
2921 | ||
7835b98b | 2922 | /* |
46cb4b7c SS |
2923 | * This routine will try to nominate the ilb (idle load balancing) |
2924 | * owner among the cpus whose ticks are stopped. ilb owner will do the idle | |
2925 | * load balancing on behalf of all those cpus. If all the cpus in the system | |
2926 | * go into this tickless mode, then there will be no ilb owner (as there is | |
2927 | * no need for one) and all the cpus will sleep till the next wakeup event | |
2928 | * arrives... | |
2929 | * | |
2930 | * For the ilb owner, tick is not stopped. And this tick will be used | |
2931 | * for idle load balancing. ilb owner will still be part of | |
2932 | * nohz.cpu_mask.. | |
7835b98b | 2933 | * |
46cb4b7c SS |
2934 | * While stopping the tick, this cpu will become the ilb owner if there |
2935 | * is no other owner. And will be the owner till that cpu becomes busy | |
2936 | * or if all cpus in the system stop their ticks at which point | |
2937 | * there is no need for ilb owner. | |
2938 | * | |
2939 | * When the ilb owner becomes busy, it nominates another owner, during the | |
2940 | * next busy scheduler_tick() | |
2941 | */ | |
2942 | int select_nohz_load_balancer(int stop_tick) | |
2943 | { | |
2944 | int cpu = smp_processor_id(); | |
2945 | ||
2946 | if (stop_tick) { | |
2947 | cpu_set(cpu, nohz.cpu_mask); | |
2948 | cpu_rq(cpu)->in_nohz_recently = 1; | |
2949 | ||
2950 | /* | |
2951 | * If we are going offline and still the leader, give up! | |
2952 | */ | |
2953 | if (cpu_is_offline(cpu) && | |
2954 | atomic_read(&nohz.load_balancer) == cpu) { | |
2955 | if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu) | |
2956 | BUG(); | |
2957 | return 0; | |
2958 | } | |
2959 | ||
2960 | /* time for ilb owner also to sleep */ | |
2961 | if (cpus_weight(nohz.cpu_mask) == num_online_cpus()) { | |
2962 | if (atomic_read(&nohz.load_balancer) == cpu) | |
2963 | atomic_set(&nohz.load_balancer, -1); | |
2964 | return 0; | |
2965 | } | |
2966 | ||
2967 | if (atomic_read(&nohz.load_balancer) == -1) { | |
2968 | /* make me the ilb owner */ | |
2969 | if (atomic_cmpxchg(&nohz.load_balancer, -1, cpu) == -1) | |
2970 | return 1; | |
2971 | } else if (atomic_read(&nohz.load_balancer) == cpu) | |
2972 | return 1; | |
2973 | } else { | |
2974 | if (!cpu_isset(cpu, nohz.cpu_mask)) | |
2975 | return 0; | |
2976 | ||
2977 | cpu_clear(cpu, nohz.cpu_mask); | |
2978 | ||
2979 | if (atomic_read(&nohz.load_balancer) == cpu) | |
2980 | if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu) | |
2981 | BUG(); | |
2982 | } | |
2983 | return 0; | |
2984 | } | |
2985 | #endif | |
2986 | ||
2987 | static DEFINE_SPINLOCK(balancing); | |
2988 | ||
2989 | /* | |
7835b98b CL |
2990 | * It checks each scheduling domain to see if it is due to be balanced, |
2991 | * and initiates a balancing operation if so. | |
2992 | * | |
2993 | * Balancing parameters are set up in arch_init_sched_domains. | |
2994 | */ | |
a9957449 | 2995 | static void rebalance_domains(int cpu, enum cpu_idle_type idle) |
7835b98b | 2996 | { |
46cb4b7c SS |
2997 | int balance = 1; |
2998 | struct rq *rq = cpu_rq(cpu); | |
7835b98b CL |
2999 | unsigned long interval; |
3000 | struct sched_domain *sd; | |
46cb4b7c | 3001 | /* Earliest time when we have to do rebalance again */ |
c9819f45 | 3002 | unsigned long next_balance = jiffies + 60*HZ; |
f549da84 | 3003 | int update_next_balance = 0; |
1da177e4 | 3004 | |
46cb4b7c | 3005 | for_each_domain(cpu, sd) { |
1da177e4 LT |
3006 | if (!(sd->flags & SD_LOAD_BALANCE)) |
3007 | continue; | |
3008 | ||
3009 | interval = sd->balance_interval; | |
d15bcfdb | 3010 | if (idle != CPU_IDLE) |
1da177e4 LT |
3011 | interval *= sd->busy_factor; |
3012 | ||
3013 | /* scale ms to jiffies */ | |
3014 | interval = msecs_to_jiffies(interval); | |
3015 | if (unlikely(!interval)) | |
3016 | interval = 1; | |
dd41f596 IM |
3017 | if (interval > HZ*NR_CPUS/10) |
3018 | interval = HZ*NR_CPUS/10; | |
3019 | ||
1da177e4 | 3020 | |
08c183f3 CL |
3021 | if (sd->flags & SD_SERIALIZE) { |
3022 | if (!spin_trylock(&balancing)) | |
3023 | goto out; | |
3024 | } | |
3025 | ||
c9819f45 | 3026 | if (time_after_eq(jiffies, sd->last_balance + interval)) { |
46cb4b7c | 3027 | if (load_balance(cpu, rq, sd, idle, &balance)) { |
fa3b6ddc SS |
3028 | /* |
3029 | * We've pulled tasks over so either we're no | |
5969fe06 NP |
3030 | * longer idle, or one of our SMT siblings is |
3031 | * not idle. | |
3032 | */ | |
d15bcfdb | 3033 | idle = CPU_NOT_IDLE; |
1da177e4 | 3034 | } |
1bd77f2d | 3035 | sd->last_balance = jiffies; |
1da177e4 | 3036 | } |
08c183f3 CL |
3037 | if (sd->flags & SD_SERIALIZE) |
3038 | spin_unlock(&balancing); | |
3039 | out: | |
f549da84 | 3040 | if (time_after(next_balance, sd->last_balance + interval)) { |
c9819f45 | 3041 | next_balance = sd->last_balance + interval; |
f549da84 SS |
3042 | update_next_balance = 1; |
3043 | } | |
783609c6 SS |
3044 | |
3045 | /* | |
3046 | * Stop the load balance at this level. There is another | |
3047 | * CPU in our sched group which is doing load balancing more | |
3048 | * actively. | |
3049 | */ | |
3050 | if (!balance) | |
3051 | break; | |
1da177e4 | 3052 | } |
f549da84 SS |
3053 | |
3054 | /* | |
3055 | * next_balance will be updated only when there is a need. | |
3056 | * When the cpu is attached to null domain for ex, it will not be | |
3057 | * updated. | |
3058 | */ | |
3059 | if (likely(update_next_balance)) | |
3060 | rq->next_balance = next_balance; | |
46cb4b7c SS |
3061 | } |
3062 | ||
3063 | /* | |
3064 | * run_rebalance_domains is triggered when needed from the scheduler tick. | |
3065 | * In CONFIG_NO_HZ case, the idle load balance owner will do the | |
3066 | * rebalancing for all the cpus for whom scheduler ticks are stopped. | |
3067 | */ | |
3068 | static void run_rebalance_domains(struct softirq_action *h) | |
3069 | { | |
dd41f596 IM |
3070 | int this_cpu = smp_processor_id(); |
3071 | struct rq *this_rq = cpu_rq(this_cpu); | |
3072 | enum cpu_idle_type idle = this_rq->idle_at_tick ? | |
3073 | CPU_IDLE : CPU_NOT_IDLE; | |
46cb4b7c | 3074 | |
dd41f596 | 3075 | rebalance_domains(this_cpu, idle); |
46cb4b7c SS |
3076 | |
3077 | #ifdef CONFIG_NO_HZ | |
3078 | /* | |
3079 | * If this cpu is the owner for idle load balancing, then do the | |
3080 | * balancing on behalf of the other idle cpus whose ticks are | |
3081 | * stopped. | |
3082 | */ | |
dd41f596 IM |
3083 | if (this_rq->idle_at_tick && |
3084 | atomic_read(&nohz.load_balancer) == this_cpu) { | |
46cb4b7c SS |
3085 | cpumask_t cpus = nohz.cpu_mask; |
3086 | struct rq *rq; | |
3087 | int balance_cpu; | |
3088 | ||
dd41f596 | 3089 | cpu_clear(this_cpu, cpus); |
46cb4b7c SS |
3090 | for_each_cpu_mask(balance_cpu, cpus) { |
3091 | /* | |
3092 | * If this cpu gets work to do, stop the load balancing | |
3093 | * work being done for other cpus. Next load | |
3094 | * balancing owner will pick it up. | |
3095 | */ | |
3096 | if (need_resched()) | |
3097 | break; | |
3098 | ||
de0cf899 | 3099 | rebalance_domains(balance_cpu, CPU_IDLE); |
46cb4b7c SS |
3100 | |
3101 | rq = cpu_rq(balance_cpu); | |
dd41f596 IM |
3102 | if (time_after(this_rq->next_balance, rq->next_balance)) |
3103 | this_rq->next_balance = rq->next_balance; | |
46cb4b7c SS |
3104 | } |
3105 | } | |
3106 | #endif | |
3107 | } | |
3108 | ||
3109 | /* | |
3110 | * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing. | |
3111 | * | |
3112 | * In case of CONFIG_NO_HZ, this is the place where we nominate a new | |
3113 | * idle load balancing owner or decide to stop the periodic load balancing, | |
3114 | * if the whole system is idle. | |
3115 | */ | |
dd41f596 | 3116 | static inline void trigger_load_balance(struct rq *rq, int cpu) |
46cb4b7c | 3117 | { |
46cb4b7c SS |
3118 | #ifdef CONFIG_NO_HZ |
3119 | /* | |
3120 | * If we were in the nohz mode recently and busy at the current | |
3121 | * scheduler tick, then check if we need to nominate new idle | |
3122 | * load balancer. | |
3123 | */ | |
3124 | if (rq->in_nohz_recently && !rq->idle_at_tick) { | |
3125 | rq->in_nohz_recently = 0; | |
3126 | ||
3127 | if (atomic_read(&nohz.load_balancer) == cpu) { | |
3128 | cpu_clear(cpu, nohz.cpu_mask); | |
3129 | atomic_set(&nohz.load_balancer, -1); | |
3130 | } | |
3131 | ||
3132 | if (atomic_read(&nohz.load_balancer) == -1) { | |
3133 | /* | |
3134 | * simple selection for now: Nominate the | |
3135 | * first cpu in the nohz list to be the next | |
3136 | * ilb owner. | |
3137 | * | |
3138 | * TBD: Traverse the sched domains and nominate | |
3139 | * the nearest cpu in the nohz.cpu_mask. | |
3140 | */ | |
3141 | int ilb = first_cpu(nohz.cpu_mask); | |
3142 | ||
3143 | if (ilb != NR_CPUS) | |
3144 | resched_cpu(ilb); | |
3145 | } | |
3146 | } | |
3147 | ||
3148 | /* | |
3149 | * If this cpu is idle and doing idle load balancing for all the | |
3150 | * cpus with ticks stopped, is it time for that to stop? | |
3151 | */ | |
3152 | if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) == cpu && | |
3153 | cpus_weight(nohz.cpu_mask) == num_online_cpus()) { | |
3154 | resched_cpu(cpu); | |
3155 | return; | |
3156 | } | |
3157 | ||
3158 | /* | |
3159 | * If this cpu is idle and the idle load balancing is done by | |
3160 | * someone else, then no need raise the SCHED_SOFTIRQ | |
3161 | */ | |
3162 | if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) != cpu && | |
3163 | cpu_isset(cpu, nohz.cpu_mask)) | |
3164 | return; | |
3165 | #endif | |
3166 | if (time_after_eq(jiffies, rq->next_balance)) | |
3167 | raise_softirq(SCHED_SOFTIRQ); | |
1da177e4 | 3168 | } |
dd41f596 IM |
3169 | |
3170 | #else /* CONFIG_SMP */ | |
3171 | ||
1da177e4 LT |
3172 | /* |
3173 | * on UP we do not need to balance between CPUs: | |
3174 | */ | |
70b97a7f | 3175 | static inline void idle_balance(int cpu, struct rq *rq) |
1da177e4 LT |
3176 | { |
3177 | } | |
dd41f596 IM |
3178 | |
3179 | /* Avoid "used but not defined" warning on UP */ | |
3180 | static int balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
3181 | unsigned long max_nr_move, unsigned long max_load_move, | |
3182 | struct sched_domain *sd, enum cpu_idle_type idle, | |
3183 | int *all_pinned, unsigned long *load_moved, | |
a4ac01c3 | 3184 | int *this_best_prio, struct rq_iterator *iterator) |
dd41f596 IM |
3185 | { |
3186 | *load_moved = 0; | |
3187 | ||
3188 | return 0; | |
3189 | } | |
3190 | ||
1da177e4 LT |
3191 | #endif |
3192 | ||
1da177e4 LT |
3193 | DEFINE_PER_CPU(struct kernel_stat, kstat); |
3194 | ||
3195 | EXPORT_PER_CPU_SYMBOL(kstat); | |
3196 | ||
3197 | /* | |
41b86e9c IM |
3198 | * Return p->sum_exec_runtime plus any more ns on the sched_clock |
3199 | * that have not yet been banked in case the task is currently running. | |
1da177e4 | 3200 | */ |
41b86e9c | 3201 | unsigned long long task_sched_runtime(struct task_struct *p) |
1da177e4 | 3202 | { |
1da177e4 | 3203 | unsigned long flags; |
41b86e9c IM |
3204 | u64 ns, delta_exec; |
3205 | struct rq *rq; | |
48f24c4d | 3206 | |
41b86e9c IM |
3207 | rq = task_rq_lock(p, &flags); |
3208 | ns = p->se.sum_exec_runtime; | |
3209 | if (rq->curr == p) { | |
a8e504d2 IM |
3210 | update_rq_clock(rq); |
3211 | delta_exec = rq->clock - p->se.exec_start; | |
41b86e9c IM |
3212 | if ((s64)delta_exec > 0) |
3213 | ns += delta_exec; | |
3214 | } | |
3215 | task_rq_unlock(rq, &flags); | |
48f24c4d | 3216 | |
1da177e4 LT |
3217 | return ns; |
3218 | } | |
3219 | ||
1da177e4 LT |
3220 | /* |
3221 | * Account user cpu time to a process. | |
3222 | * @p: the process that the cpu time gets accounted to | |
3223 | * @hardirq_offset: the offset to subtract from hardirq_count() | |
3224 | * @cputime: the cpu time spent in user space since the last update | |
3225 | */ | |
3226 | void account_user_time(struct task_struct *p, cputime_t cputime) | |
3227 | { | |
3228 | struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; | |
3229 | cputime64_t tmp; | |
3230 | ||
3231 | p->utime = cputime_add(p->utime, cputime); | |
3232 | ||
3233 | /* Add user time to cpustat. */ | |
3234 | tmp = cputime_to_cputime64(cputime); | |
3235 | if (TASK_NICE(p) > 0) | |
3236 | cpustat->nice = cputime64_add(cpustat->nice, tmp); | |
3237 | else | |
3238 | cpustat->user = cputime64_add(cpustat->user, tmp); | |
3239 | } | |
3240 | ||
3241 | /* | |
3242 | * Account system cpu time to a process. | |
3243 | * @p: the process that the cpu time gets accounted to | |
3244 | * @hardirq_offset: the offset to subtract from hardirq_count() | |
3245 | * @cputime: the cpu time spent in kernel space since the last update | |
3246 | */ | |
3247 | void account_system_time(struct task_struct *p, int hardirq_offset, | |
3248 | cputime_t cputime) | |
3249 | { | |
3250 | struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; | |
70b97a7f | 3251 | struct rq *rq = this_rq(); |
1da177e4 LT |
3252 | cputime64_t tmp; |
3253 | ||
3254 | p->stime = cputime_add(p->stime, cputime); | |
3255 | ||
3256 | /* Add system time to cpustat. */ | |
3257 | tmp = cputime_to_cputime64(cputime); | |
3258 | if (hardirq_count() - hardirq_offset) | |
3259 | cpustat->irq = cputime64_add(cpustat->irq, tmp); | |
3260 | else if (softirq_count()) | |
3261 | cpustat->softirq = cputime64_add(cpustat->softirq, tmp); | |
3262 | else if (p != rq->idle) | |
3263 | cpustat->system = cputime64_add(cpustat->system, tmp); | |
3264 | else if (atomic_read(&rq->nr_iowait) > 0) | |
3265 | cpustat->iowait = cputime64_add(cpustat->iowait, tmp); | |
3266 | else | |
3267 | cpustat->idle = cputime64_add(cpustat->idle, tmp); | |
3268 | /* Account for system time used */ | |
3269 | acct_update_integrals(p); | |
1da177e4 LT |
3270 | } |
3271 | ||
3272 | /* | |
3273 | * Account for involuntary wait time. | |
3274 | * @p: the process from which the cpu time has been stolen | |
3275 | * @steal: the cpu time spent in involuntary wait | |
3276 | */ | |
3277 | void account_steal_time(struct task_struct *p, cputime_t steal) | |
3278 | { | |
3279 | struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; | |
3280 | cputime64_t tmp = cputime_to_cputime64(steal); | |
70b97a7f | 3281 | struct rq *rq = this_rq(); |
1da177e4 LT |
3282 | |
3283 | if (p == rq->idle) { | |
3284 | p->stime = cputime_add(p->stime, steal); | |
3285 | if (atomic_read(&rq->nr_iowait) > 0) | |
3286 | cpustat->iowait = cputime64_add(cpustat->iowait, tmp); | |
3287 | else | |
3288 | cpustat->idle = cputime64_add(cpustat->idle, tmp); | |
3289 | } else | |
3290 | cpustat->steal = cputime64_add(cpustat->steal, tmp); | |
3291 | } | |
3292 | ||
7835b98b CL |
3293 | /* |
3294 | * This function gets called by the timer code, with HZ frequency. | |
3295 | * We call it with interrupts disabled. | |
3296 | * | |
3297 | * It also gets called by the fork code, when changing the parent's | |
3298 | * timeslices. | |
3299 | */ | |
3300 | void scheduler_tick(void) | |
3301 | { | |
7835b98b CL |
3302 | int cpu = smp_processor_id(); |
3303 | struct rq *rq = cpu_rq(cpu); | |
dd41f596 | 3304 | struct task_struct *curr = rq->curr; |
529c7726 | 3305 | u64 next_tick = rq->tick_timestamp + TICK_NSEC; |
dd41f596 IM |
3306 | |
3307 | spin_lock(&rq->lock); | |
546fe3c9 | 3308 | __update_rq_clock(rq); |
529c7726 IM |
3309 | /* |
3310 | * Let rq->clock advance by at least TICK_NSEC: | |
3311 | */ | |
3312 | if (unlikely(rq->clock < next_tick)) | |
3313 | rq->clock = next_tick; | |
3314 | rq->tick_timestamp = rq->clock; | |
f1a438d8 | 3315 | update_cpu_load(rq); |
dd41f596 IM |
3316 | if (curr != rq->idle) /* FIXME: needed? */ |
3317 | curr->sched_class->task_tick(rq, curr); | |
dd41f596 | 3318 | spin_unlock(&rq->lock); |
7835b98b | 3319 | |
e418e1c2 | 3320 | #ifdef CONFIG_SMP |
dd41f596 IM |
3321 | rq->idle_at_tick = idle_cpu(cpu); |
3322 | trigger_load_balance(rq, cpu); | |
e418e1c2 | 3323 | #endif |
1da177e4 LT |
3324 | } |
3325 | ||
1da177e4 LT |
3326 | #if defined(CONFIG_PREEMPT) && defined(CONFIG_DEBUG_PREEMPT) |
3327 | ||
3328 | void fastcall add_preempt_count(int val) | |
3329 | { | |
3330 | /* | |
3331 | * Underflow? | |
3332 | */ | |
9a11b49a IM |
3333 | if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0))) |
3334 | return; | |
1da177e4 LT |
3335 | preempt_count() += val; |
3336 | /* | |
3337 | * Spinlock count overflowing soon? | |
3338 | */ | |
33859f7f MOS |
3339 | DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >= |
3340 | PREEMPT_MASK - 10); | |
1da177e4 LT |
3341 | } |
3342 | EXPORT_SYMBOL(add_preempt_count); | |
3343 | ||
3344 | void fastcall sub_preempt_count(int val) | |
3345 | { | |
3346 | /* | |
3347 | * Underflow? | |
3348 | */ | |
9a11b49a IM |
3349 | if (DEBUG_LOCKS_WARN_ON(val > preempt_count())) |
3350 | return; | |
1da177e4 LT |
3351 | /* |
3352 | * Is the spinlock portion underflowing? | |
3353 | */ | |
9a11b49a IM |
3354 | if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) && |
3355 | !(preempt_count() & PREEMPT_MASK))) | |
3356 | return; | |
3357 | ||
1da177e4 LT |
3358 | preempt_count() -= val; |
3359 | } | |
3360 | EXPORT_SYMBOL(sub_preempt_count); | |
3361 | ||
3362 | #endif | |
3363 | ||
3364 | /* | |
dd41f596 | 3365 | * Print scheduling while atomic bug: |
1da177e4 | 3366 | */ |
dd41f596 | 3367 | static noinline void __schedule_bug(struct task_struct *prev) |
1da177e4 | 3368 | { |
dd41f596 IM |
3369 | printk(KERN_ERR "BUG: scheduling while atomic: %s/0x%08x/%d\n", |
3370 | prev->comm, preempt_count(), prev->pid); | |
3371 | debug_show_held_locks(prev); | |
3372 | if (irqs_disabled()) | |
3373 | print_irqtrace_events(prev); | |
3374 | dump_stack(); | |
3375 | } | |
1da177e4 | 3376 | |
dd41f596 IM |
3377 | /* |
3378 | * Various schedule()-time debugging checks and statistics: | |
3379 | */ | |
3380 | static inline void schedule_debug(struct task_struct *prev) | |
3381 | { | |
1da177e4 LT |
3382 | /* |
3383 | * Test if we are atomic. Since do_exit() needs to call into | |
3384 | * schedule() atomically, we ignore that path for now. | |
3385 | * Otherwise, whine if we are scheduling when we should not be. | |
3386 | */ | |
dd41f596 IM |
3387 | if (unlikely(in_atomic_preempt_off()) && unlikely(!prev->exit_state)) |
3388 | __schedule_bug(prev); | |
3389 | ||
1da177e4 LT |
3390 | profile_hit(SCHED_PROFILING, __builtin_return_address(0)); |
3391 | ||
2d72376b | 3392 | schedstat_inc(this_rq(), sched_count); |
b8efb561 IM |
3393 | #ifdef CONFIG_SCHEDSTATS |
3394 | if (unlikely(prev->lock_depth >= 0)) { | |
2d72376b IM |
3395 | schedstat_inc(this_rq(), bkl_count); |
3396 | schedstat_inc(prev, sched_info.bkl_count); | |
b8efb561 IM |
3397 | } |
3398 | #endif | |
dd41f596 IM |
3399 | } |
3400 | ||
3401 | /* | |
3402 | * Pick up the highest-prio task: | |
3403 | */ | |
3404 | static inline struct task_struct * | |
ff95f3df | 3405 | pick_next_task(struct rq *rq, struct task_struct *prev) |
dd41f596 | 3406 | { |
5522d5d5 | 3407 | const struct sched_class *class; |
dd41f596 | 3408 | struct task_struct *p; |
1da177e4 LT |
3409 | |
3410 | /* | |
dd41f596 IM |
3411 | * Optimization: we know that if all tasks are in |
3412 | * the fair class we can call that function directly: | |
1da177e4 | 3413 | */ |
dd41f596 | 3414 | if (likely(rq->nr_running == rq->cfs.nr_running)) { |
fb8d4724 | 3415 | p = fair_sched_class.pick_next_task(rq); |
dd41f596 IM |
3416 | if (likely(p)) |
3417 | return p; | |
1da177e4 LT |
3418 | } |
3419 | ||
dd41f596 IM |
3420 | class = sched_class_highest; |
3421 | for ( ; ; ) { | |
fb8d4724 | 3422 | p = class->pick_next_task(rq); |
dd41f596 IM |
3423 | if (p) |
3424 | return p; | |
3425 | /* | |
3426 | * Will never be NULL as the idle class always | |
3427 | * returns a non-NULL p: | |
3428 | */ | |
3429 | class = class->next; | |
3430 | } | |
3431 | } | |
1da177e4 | 3432 | |
dd41f596 IM |
3433 | /* |
3434 | * schedule() is the main scheduler function. | |
3435 | */ | |
3436 | asmlinkage void __sched schedule(void) | |
3437 | { | |
3438 | struct task_struct *prev, *next; | |
3439 | long *switch_count; | |
3440 | struct rq *rq; | |
dd41f596 IM |
3441 | int cpu; |
3442 | ||
3443 | need_resched: | |
3444 | preempt_disable(); | |
3445 | cpu = smp_processor_id(); | |
3446 | rq = cpu_rq(cpu); | |
3447 | rcu_qsctr_inc(cpu); | |
3448 | prev = rq->curr; | |
3449 | switch_count = &prev->nivcsw; | |
3450 | ||
3451 | release_kernel_lock(prev); | |
3452 | need_resched_nonpreemptible: | |
3453 | ||
3454 | schedule_debug(prev); | |
1da177e4 | 3455 | |
1e819950 IM |
3456 | /* |
3457 | * Do the rq-clock update outside the rq lock: | |
3458 | */ | |
3459 | local_irq_disable(); | |
c1b3da3e | 3460 | __update_rq_clock(rq); |
1e819950 IM |
3461 | spin_lock(&rq->lock); |
3462 | clear_tsk_need_resched(prev); | |
1da177e4 | 3463 | |
1da177e4 | 3464 | if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) { |
1da177e4 | 3465 | if (unlikely((prev->state & TASK_INTERRUPTIBLE) && |
dd41f596 | 3466 | unlikely(signal_pending(prev)))) { |
1da177e4 | 3467 | prev->state = TASK_RUNNING; |
dd41f596 | 3468 | } else { |
2e1cb74a | 3469 | deactivate_task(rq, prev, 1); |
1da177e4 | 3470 | } |
dd41f596 | 3471 | switch_count = &prev->nvcsw; |
1da177e4 LT |
3472 | } |
3473 | ||
dd41f596 | 3474 | if (unlikely(!rq->nr_running)) |
1da177e4 | 3475 | idle_balance(cpu, rq); |
1da177e4 | 3476 | |
31ee529c | 3477 | prev->sched_class->put_prev_task(rq, prev); |
ff95f3df | 3478 | next = pick_next_task(rq, prev); |
1da177e4 LT |
3479 | |
3480 | sched_info_switch(prev, next); | |
dd41f596 | 3481 | |
1da177e4 | 3482 | if (likely(prev != next)) { |
1da177e4 LT |
3483 | rq->nr_switches++; |
3484 | rq->curr = next; | |
3485 | ++*switch_count; | |
3486 | ||
dd41f596 | 3487 | context_switch(rq, prev, next); /* unlocks the rq */ |
1da177e4 LT |
3488 | } else |
3489 | spin_unlock_irq(&rq->lock); | |
3490 | ||
dd41f596 IM |
3491 | if (unlikely(reacquire_kernel_lock(current) < 0)) { |
3492 | cpu = smp_processor_id(); | |
3493 | rq = cpu_rq(cpu); | |
1da177e4 | 3494 | goto need_resched_nonpreemptible; |
dd41f596 | 3495 | } |
1da177e4 LT |
3496 | preempt_enable_no_resched(); |
3497 | if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) | |
3498 | goto need_resched; | |
3499 | } | |
1da177e4 LT |
3500 | EXPORT_SYMBOL(schedule); |
3501 | ||
3502 | #ifdef CONFIG_PREEMPT | |
3503 | /* | |
2ed6e34f | 3504 | * this is the entry point to schedule() from in-kernel preemption |
1da177e4 LT |
3505 | * off of preempt_enable. Kernel preemptions off return from interrupt |
3506 | * occur there and call schedule directly. | |
3507 | */ | |
3508 | asmlinkage void __sched preempt_schedule(void) | |
3509 | { | |
3510 | struct thread_info *ti = current_thread_info(); | |
3511 | #ifdef CONFIG_PREEMPT_BKL | |
3512 | struct task_struct *task = current; | |
3513 | int saved_lock_depth; | |
3514 | #endif | |
3515 | /* | |
3516 | * If there is a non-zero preempt_count or interrupts are disabled, | |
3517 | * we do not want to preempt the current task. Just return.. | |
3518 | */ | |
beed33a8 | 3519 | if (likely(ti->preempt_count || irqs_disabled())) |
1da177e4 LT |
3520 | return; |
3521 | ||
3a5c359a AK |
3522 | do { |
3523 | add_preempt_count(PREEMPT_ACTIVE); | |
3524 | ||
3525 | /* | |
3526 | * We keep the big kernel semaphore locked, but we | |
3527 | * clear ->lock_depth so that schedule() doesnt | |
3528 | * auto-release the semaphore: | |
3529 | */ | |
1da177e4 | 3530 | #ifdef CONFIG_PREEMPT_BKL |
3a5c359a AK |
3531 | saved_lock_depth = task->lock_depth; |
3532 | task->lock_depth = -1; | |
1da177e4 | 3533 | #endif |
3a5c359a | 3534 | schedule(); |
1da177e4 | 3535 | #ifdef CONFIG_PREEMPT_BKL |
3a5c359a | 3536 | task->lock_depth = saved_lock_depth; |
1da177e4 | 3537 | #endif |
3a5c359a | 3538 | sub_preempt_count(PREEMPT_ACTIVE); |
1da177e4 | 3539 | |
3a5c359a AK |
3540 | /* |
3541 | * Check again in case we missed a preemption opportunity | |
3542 | * between schedule and now. | |
3543 | */ | |
3544 | barrier(); | |
3545 | } while (unlikely(test_thread_flag(TIF_NEED_RESCHED))); | |
1da177e4 | 3546 | } |
1da177e4 LT |
3547 | EXPORT_SYMBOL(preempt_schedule); |
3548 | ||
3549 | /* | |
2ed6e34f | 3550 | * this is the entry point to schedule() from kernel preemption |
1da177e4 LT |
3551 | * off of irq context. |
3552 | * Note, that this is called and return with irqs disabled. This will | |
3553 | * protect us against recursive calling from irq. | |
3554 | */ | |
3555 | asmlinkage void __sched preempt_schedule_irq(void) | |
3556 | { | |
3557 | struct thread_info *ti = current_thread_info(); | |
3558 | #ifdef CONFIG_PREEMPT_BKL | |
3559 | struct task_struct *task = current; | |
3560 | int saved_lock_depth; | |
3561 | #endif | |
2ed6e34f | 3562 | /* Catch callers which need to be fixed */ |
1da177e4 LT |
3563 | BUG_ON(ti->preempt_count || !irqs_disabled()); |
3564 | ||
3a5c359a AK |
3565 | do { |
3566 | add_preempt_count(PREEMPT_ACTIVE); | |
3567 | ||
3568 | /* | |
3569 | * We keep the big kernel semaphore locked, but we | |
3570 | * clear ->lock_depth so that schedule() doesnt | |
3571 | * auto-release the semaphore: | |
3572 | */ | |
1da177e4 | 3573 | #ifdef CONFIG_PREEMPT_BKL |
3a5c359a AK |
3574 | saved_lock_depth = task->lock_depth; |
3575 | task->lock_depth = -1; | |
1da177e4 | 3576 | #endif |
3a5c359a AK |
3577 | local_irq_enable(); |
3578 | schedule(); | |
3579 | local_irq_disable(); | |
1da177e4 | 3580 | #ifdef CONFIG_PREEMPT_BKL |
3a5c359a | 3581 | task->lock_depth = saved_lock_depth; |
1da177e4 | 3582 | #endif |
3a5c359a | 3583 | sub_preempt_count(PREEMPT_ACTIVE); |
1da177e4 | 3584 | |
3a5c359a AK |
3585 | /* |
3586 | * Check again in case we missed a preemption opportunity | |
3587 | * between schedule and now. | |
3588 | */ | |
3589 | barrier(); | |
3590 | } while (unlikely(test_thread_flag(TIF_NEED_RESCHED))); | |
1da177e4 LT |
3591 | } |
3592 | ||
3593 | #endif /* CONFIG_PREEMPT */ | |
3594 | ||
95cdf3b7 IM |
3595 | int default_wake_function(wait_queue_t *curr, unsigned mode, int sync, |
3596 | void *key) | |
1da177e4 | 3597 | { |
48f24c4d | 3598 | return try_to_wake_up(curr->private, mode, sync); |
1da177e4 | 3599 | } |
1da177e4 LT |
3600 | EXPORT_SYMBOL(default_wake_function); |
3601 | ||
3602 | /* | |
3603 | * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just | |
3604 | * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve | |
3605 | * number) then we wake all the non-exclusive tasks and one exclusive task. | |
3606 | * | |
3607 | * There are circumstances in which we can try to wake a task which has already | |
3608 | * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns | |
3609 | * zero in this (rare) case, and we handle it by continuing to scan the queue. | |
3610 | */ | |
3611 | static void __wake_up_common(wait_queue_head_t *q, unsigned int mode, | |
3612 | int nr_exclusive, int sync, void *key) | |
3613 | { | |
2e45874c | 3614 | wait_queue_t *curr, *next; |
1da177e4 | 3615 | |
2e45874c | 3616 | list_for_each_entry_safe(curr, next, &q->task_list, task_list) { |
48f24c4d IM |
3617 | unsigned flags = curr->flags; |
3618 | ||
1da177e4 | 3619 | if (curr->func(curr, mode, sync, key) && |
48f24c4d | 3620 | (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive) |
1da177e4 LT |
3621 | break; |
3622 | } | |
3623 | } | |
3624 | ||
3625 | /** | |
3626 | * __wake_up - wake up threads blocked on a waitqueue. | |
3627 | * @q: the waitqueue | |
3628 | * @mode: which threads | |
3629 | * @nr_exclusive: how many wake-one or wake-many threads to wake up | |
67be2dd1 | 3630 | * @key: is directly passed to the wakeup function |
1da177e4 LT |
3631 | */ |
3632 | void fastcall __wake_up(wait_queue_head_t *q, unsigned int mode, | |
95cdf3b7 | 3633 | int nr_exclusive, void *key) |
1da177e4 LT |
3634 | { |
3635 | unsigned long flags; | |
3636 | ||
3637 | spin_lock_irqsave(&q->lock, flags); | |
3638 | __wake_up_common(q, mode, nr_exclusive, 0, key); | |
3639 | spin_unlock_irqrestore(&q->lock, flags); | |
3640 | } | |
1da177e4 LT |
3641 | EXPORT_SYMBOL(__wake_up); |
3642 | ||
3643 | /* | |
3644 | * Same as __wake_up but called with the spinlock in wait_queue_head_t held. | |
3645 | */ | |
3646 | void fastcall __wake_up_locked(wait_queue_head_t *q, unsigned int mode) | |
3647 | { | |
3648 | __wake_up_common(q, mode, 1, 0, NULL); | |
3649 | } | |
3650 | ||
3651 | /** | |
67be2dd1 | 3652 | * __wake_up_sync - wake up threads blocked on a waitqueue. |
1da177e4 LT |
3653 | * @q: the waitqueue |
3654 | * @mode: which threads | |
3655 | * @nr_exclusive: how many wake-one or wake-many threads to wake up | |
3656 | * | |
3657 | * The sync wakeup differs that the waker knows that it will schedule | |
3658 | * away soon, so while the target thread will be woken up, it will not | |
3659 | * be migrated to another CPU - ie. the two threads are 'synchronized' | |
3660 | * with each other. This can prevent needless bouncing between CPUs. | |
3661 | * | |
3662 | * On UP it can prevent extra preemption. | |
3663 | */ | |
95cdf3b7 IM |
3664 | void fastcall |
3665 | __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive) | |
1da177e4 LT |
3666 | { |
3667 | unsigned long flags; | |
3668 | int sync = 1; | |
3669 | ||
3670 | if (unlikely(!q)) | |
3671 | return; | |
3672 | ||
3673 | if (unlikely(!nr_exclusive)) | |
3674 | sync = 0; | |
3675 | ||
3676 | spin_lock_irqsave(&q->lock, flags); | |
3677 | __wake_up_common(q, mode, nr_exclusive, sync, NULL); | |
3678 | spin_unlock_irqrestore(&q->lock, flags); | |
3679 | } | |
3680 | EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */ | |
3681 | ||
3682 | void fastcall complete(struct completion *x) | |
3683 | { | |
3684 | unsigned long flags; | |
3685 | ||
3686 | spin_lock_irqsave(&x->wait.lock, flags); | |
3687 | x->done++; | |
3688 | __wake_up_common(&x->wait, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, | |
3689 | 1, 0, NULL); | |
3690 | spin_unlock_irqrestore(&x->wait.lock, flags); | |
3691 | } | |
3692 | EXPORT_SYMBOL(complete); | |
3693 | ||
3694 | void fastcall complete_all(struct completion *x) | |
3695 | { | |
3696 | unsigned long flags; | |
3697 | ||
3698 | spin_lock_irqsave(&x->wait.lock, flags); | |
3699 | x->done += UINT_MAX/2; | |
3700 | __wake_up_common(&x->wait, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, | |
3701 | 0, 0, NULL); | |
3702 | spin_unlock_irqrestore(&x->wait.lock, flags); | |
3703 | } | |
3704 | EXPORT_SYMBOL(complete_all); | |
3705 | ||
8cbbe86d AK |
3706 | static inline long __sched |
3707 | do_wait_for_common(struct completion *x, long timeout, int state) | |
1da177e4 | 3708 | { |
1da177e4 LT |
3709 | if (!x->done) { |
3710 | DECLARE_WAITQUEUE(wait, current); | |
3711 | ||
3712 | wait.flags |= WQ_FLAG_EXCLUSIVE; | |
3713 | __add_wait_queue_tail(&x->wait, &wait); | |
3714 | do { | |
8cbbe86d AK |
3715 | if (state == TASK_INTERRUPTIBLE && |
3716 | signal_pending(current)) { | |
3717 | __remove_wait_queue(&x->wait, &wait); | |
3718 | return -ERESTARTSYS; | |
3719 | } | |
3720 | __set_current_state(state); | |
1da177e4 LT |
3721 | spin_unlock_irq(&x->wait.lock); |
3722 | timeout = schedule_timeout(timeout); | |
3723 | spin_lock_irq(&x->wait.lock); | |
3724 | if (!timeout) { | |
3725 | __remove_wait_queue(&x->wait, &wait); | |
8cbbe86d | 3726 | return timeout; |
1da177e4 LT |
3727 | } |
3728 | } while (!x->done); | |
3729 | __remove_wait_queue(&x->wait, &wait); | |
3730 | } | |
3731 | x->done--; | |
1da177e4 LT |
3732 | return timeout; |
3733 | } | |
1da177e4 | 3734 | |
8cbbe86d AK |
3735 | static long __sched |
3736 | wait_for_common(struct completion *x, long timeout, int state) | |
1da177e4 | 3737 | { |
1da177e4 LT |
3738 | might_sleep(); |
3739 | ||
3740 | spin_lock_irq(&x->wait.lock); | |
8cbbe86d | 3741 | timeout = do_wait_for_common(x, timeout, state); |
1da177e4 | 3742 | spin_unlock_irq(&x->wait.lock); |
8cbbe86d AK |
3743 | return timeout; |
3744 | } | |
1da177e4 | 3745 | |
8cbbe86d AK |
3746 | void fastcall __sched wait_for_completion(struct completion *x) |
3747 | { | |
3748 | wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE); | |
1da177e4 | 3749 | } |
8cbbe86d | 3750 | EXPORT_SYMBOL(wait_for_completion); |
1da177e4 LT |
3751 | |
3752 | unsigned long fastcall __sched | |
8cbbe86d | 3753 | wait_for_completion_timeout(struct completion *x, unsigned long timeout) |
1da177e4 | 3754 | { |
8cbbe86d | 3755 | return wait_for_common(x, timeout, TASK_UNINTERRUPTIBLE); |
1da177e4 | 3756 | } |
8cbbe86d | 3757 | EXPORT_SYMBOL(wait_for_completion_timeout); |
1da177e4 | 3758 | |
8cbbe86d | 3759 | int __sched wait_for_completion_interruptible(struct completion *x) |
0fec171c | 3760 | { |
8cbbe86d | 3761 | return wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_INTERRUPTIBLE); |
0fec171c | 3762 | } |
8cbbe86d | 3763 | EXPORT_SYMBOL(wait_for_completion_interruptible); |
1da177e4 | 3764 | |
8cbbe86d AK |
3765 | unsigned long fastcall __sched |
3766 | wait_for_completion_interruptible_timeout(struct completion *x, | |
3767 | unsigned long timeout) | |
0fec171c | 3768 | { |
8cbbe86d | 3769 | return wait_for_common(x, timeout, TASK_INTERRUPTIBLE); |
0fec171c | 3770 | } |
8cbbe86d | 3771 | EXPORT_SYMBOL(wait_for_completion_interruptible_timeout); |
1da177e4 | 3772 | |
8cbbe86d AK |
3773 | static long __sched |
3774 | sleep_on_common(wait_queue_head_t *q, int state, long timeout) | |
1da177e4 | 3775 | { |
0fec171c IM |
3776 | unsigned long flags; |
3777 | wait_queue_t wait; | |
3778 | ||
3779 | init_waitqueue_entry(&wait, current); | |
1da177e4 | 3780 | |
8cbbe86d | 3781 | __set_current_state(state); |
1da177e4 | 3782 | |
8cbbe86d AK |
3783 | spin_lock_irqsave(&q->lock, flags); |
3784 | __add_wait_queue(q, &wait); | |
3785 | spin_unlock(&q->lock); | |
3786 | timeout = schedule_timeout(timeout); | |
3787 | spin_lock_irq(&q->lock); | |
3788 | __remove_wait_queue(q, &wait); | |
3789 | spin_unlock_irqrestore(&q->lock, flags); | |
3790 | ||
3791 | return timeout; | |
3792 | } | |
3793 | ||
3794 | void __sched interruptible_sleep_on(wait_queue_head_t *q) | |
3795 | { | |
3796 | sleep_on_common(q, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); | |
1da177e4 | 3797 | } |
1da177e4 LT |
3798 | EXPORT_SYMBOL(interruptible_sleep_on); |
3799 | ||
0fec171c | 3800 | long __sched |
95cdf3b7 | 3801 | interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout) |
1da177e4 | 3802 | { |
8cbbe86d | 3803 | return sleep_on_common(q, TASK_INTERRUPTIBLE, timeout); |
1da177e4 | 3804 | } |
1da177e4 LT |
3805 | EXPORT_SYMBOL(interruptible_sleep_on_timeout); |
3806 | ||
0fec171c | 3807 | void __sched sleep_on(wait_queue_head_t *q) |
1da177e4 | 3808 | { |
8cbbe86d | 3809 | sleep_on_common(q, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); |
1da177e4 | 3810 | } |
1da177e4 LT |
3811 | EXPORT_SYMBOL(sleep_on); |
3812 | ||
0fec171c | 3813 | long __sched sleep_on_timeout(wait_queue_head_t *q, long timeout) |
1da177e4 | 3814 | { |
8cbbe86d | 3815 | return sleep_on_common(q, TASK_UNINTERRUPTIBLE, timeout); |
1da177e4 | 3816 | } |
1da177e4 LT |
3817 | EXPORT_SYMBOL(sleep_on_timeout); |
3818 | ||
b29739f9 IM |
3819 | #ifdef CONFIG_RT_MUTEXES |
3820 | ||
3821 | /* | |
3822 | * rt_mutex_setprio - set the current priority of a task | |
3823 | * @p: task | |
3824 | * @prio: prio value (kernel-internal form) | |
3825 | * | |
3826 | * This function changes the 'effective' priority of a task. It does | |
3827 | * not touch ->normal_prio like __setscheduler(). | |
3828 | * | |
3829 | * Used by the rt_mutex code to implement priority inheritance logic. | |
3830 | */ | |
36c8b586 | 3831 | void rt_mutex_setprio(struct task_struct *p, int prio) |
b29739f9 IM |
3832 | { |
3833 | unsigned long flags; | |
83b699ed | 3834 | int oldprio, on_rq, running; |
70b97a7f | 3835 | struct rq *rq; |
b29739f9 IM |
3836 | |
3837 | BUG_ON(prio < 0 || prio > MAX_PRIO); | |
3838 | ||
3839 | rq = task_rq_lock(p, &flags); | |
a8e504d2 | 3840 | update_rq_clock(rq); |
b29739f9 | 3841 | |
d5f9f942 | 3842 | oldprio = p->prio; |
dd41f596 | 3843 | on_rq = p->se.on_rq; |
83b699ed SV |
3844 | running = task_running(rq, p); |
3845 | if (on_rq) { | |
69be72c1 | 3846 | dequeue_task(rq, p, 0); |
83b699ed SV |
3847 | if (running) |
3848 | p->sched_class->put_prev_task(rq, p); | |
3849 | } | |
dd41f596 IM |
3850 | |
3851 | if (rt_prio(prio)) | |
3852 | p->sched_class = &rt_sched_class; | |
3853 | else | |
3854 | p->sched_class = &fair_sched_class; | |
3855 | ||
b29739f9 IM |
3856 | p->prio = prio; |
3857 | ||
dd41f596 | 3858 | if (on_rq) { |
83b699ed SV |
3859 | if (running) |
3860 | p->sched_class->set_curr_task(rq); | |
8159f87e | 3861 | enqueue_task(rq, p, 0); |
b29739f9 IM |
3862 | /* |
3863 | * Reschedule if we are currently running on this runqueue and | |
d5f9f942 AM |
3864 | * our priority decreased, or if we are not currently running on |
3865 | * this runqueue and our priority is higher than the current's | |
b29739f9 | 3866 | */ |
83b699ed | 3867 | if (running) { |
d5f9f942 AM |
3868 | if (p->prio > oldprio) |
3869 | resched_task(rq->curr); | |
dd41f596 IM |
3870 | } else { |
3871 | check_preempt_curr(rq, p); | |
3872 | } | |
b29739f9 IM |
3873 | } |
3874 | task_rq_unlock(rq, &flags); | |
3875 | } | |
3876 | ||
3877 | #endif | |
3878 | ||
36c8b586 | 3879 | void set_user_nice(struct task_struct *p, long nice) |
1da177e4 | 3880 | { |
dd41f596 | 3881 | int old_prio, delta, on_rq; |
1da177e4 | 3882 | unsigned long flags; |
70b97a7f | 3883 | struct rq *rq; |
1da177e4 LT |
3884 | |
3885 | if (TASK_NICE(p) == nice || nice < -20 || nice > 19) | |
3886 | return; | |
3887 | /* | |
3888 | * We have to be careful, if called from sys_setpriority(), | |
3889 | * the task might be in the middle of scheduling on another CPU. | |
3890 | */ | |
3891 | rq = task_rq_lock(p, &flags); | |
a8e504d2 | 3892 | update_rq_clock(rq); |
1da177e4 LT |
3893 | /* |
3894 | * The RT priorities are set via sched_setscheduler(), but we still | |
3895 | * allow the 'normal' nice value to be set - but as expected | |
3896 | * it wont have any effect on scheduling until the task is | |
dd41f596 | 3897 | * SCHED_FIFO/SCHED_RR: |
1da177e4 | 3898 | */ |
e05606d3 | 3899 | if (task_has_rt_policy(p)) { |
1da177e4 LT |
3900 | p->static_prio = NICE_TO_PRIO(nice); |
3901 | goto out_unlock; | |
3902 | } | |
dd41f596 IM |
3903 | on_rq = p->se.on_rq; |
3904 | if (on_rq) { | |
69be72c1 | 3905 | dequeue_task(rq, p, 0); |
79b5dddf | 3906 | dec_load(rq, p); |
2dd73a4f | 3907 | } |
1da177e4 | 3908 | |
1da177e4 | 3909 | p->static_prio = NICE_TO_PRIO(nice); |
2dd73a4f | 3910 | set_load_weight(p); |
b29739f9 IM |
3911 | old_prio = p->prio; |
3912 | p->prio = effective_prio(p); | |
3913 | delta = p->prio - old_prio; | |
1da177e4 | 3914 | |
dd41f596 | 3915 | if (on_rq) { |
8159f87e | 3916 | enqueue_task(rq, p, 0); |
29b4b623 | 3917 | inc_load(rq, p); |
1da177e4 | 3918 | /* |
d5f9f942 AM |
3919 | * If the task increased its priority or is running and |
3920 | * lowered its priority, then reschedule its CPU: | |
1da177e4 | 3921 | */ |
d5f9f942 | 3922 | if (delta < 0 || (delta > 0 && task_running(rq, p))) |
1da177e4 LT |
3923 | resched_task(rq->curr); |
3924 | } | |
3925 | out_unlock: | |
3926 | task_rq_unlock(rq, &flags); | |
3927 | } | |
1da177e4 LT |
3928 | EXPORT_SYMBOL(set_user_nice); |
3929 | ||
e43379f1 MM |
3930 | /* |
3931 | * can_nice - check if a task can reduce its nice value | |
3932 | * @p: task | |
3933 | * @nice: nice value | |
3934 | */ | |
36c8b586 | 3935 | int can_nice(const struct task_struct *p, const int nice) |
e43379f1 | 3936 | { |
024f4747 MM |
3937 | /* convert nice value [19,-20] to rlimit style value [1,40] */ |
3938 | int nice_rlim = 20 - nice; | |
48f24c4d | 3939 | |
e43379f1 MM |
3940 | return (nice_rlim <= p->signal->rlim[RLIMIT_NICE].rlim_cur || |
3941 | capable(CAP_SYS_NICE)); | |
3942 | } | |
3943 | ||
1da177e4 LT |
3944 | #ifdef __ARCH_WANT_SYS_NICE |
3945 | ||
3946 | /* | |
3947 | * sys_nice - change the priority of the current process. | |
3948 | * @increment: priority increment | |
3949 | * | |
3950 | * sys_setpriority is a more generic, but much slower function that | |
3951 | * does similar things. | |
3952 | */ | |
3953 | asmlinkage long sys_nice(int increment) | |
3954 | { | |
48f24c4d | 3955 | long nice, retval; |
1da177e4 LT |
3956 | |
3957 | /* | |
3958 | * Setpriority might change our priority at the same moment. | |
3959 | * We don't have to worry. Conceptually one call occurs first | |
3960 | * and we have a single winner. | |
3961 | */ | |
e43379f1 MM |
3962 | if (increment < -40) |
3963 | increment = -40; | |
1da177e4 LT |
3964 | if (increment > 40) |
3965 | increment = 40; | |
3966 | ||
3967 | nice = PRIO_TO_NICE(current->static_prio) + increment; | |
3968 | if (nice < -20) | |
3969 | nice = -20; | |
3970 | if (nice > 19) | |
3971 | nice = 19; | |
3972 | ||
e43379f1 MM |
3973 | if (increment < 0 && !can_nice(current, nice)) |
3974 | return -EPERM; | |
3975 | ||
1da177e4 LT |
3976 | retval = security_task_setnice(current, nice); |
3977 | if (retval) | |
3978 | return retval; | |
3979 | ||
3980 | set_user_nice(current, nice); | |
3981 | return 0; | |
3982 | } | |
3983 | ||
3984 | #endif | |
3985 | ||
3986 | /** | |
3987 | * task_prio - return the priority value of a given task. | |
3988 | * @p: the task in question. | |
3989 | * | |
3990 | * This is the priority value as seen by users in /proc. | |
3991 | * RT tasks are offset by -200. Normal tasks are centered | |
3992 | * around 0, value goes from -16 to +15. | |
3993 | */ | |
36c8b586 | 3994 | int task_prio(const struct task_struct *p) |
1da177e4 LT |
3995 | { |
3996 | return p->prio - MAX_RT_PRIO; | |
3997 | } | |
3998 | ||
3999 | /** | |
4000 | * task_nice - return the nice value of a given task. | |
4001 | * @p: the task in question. | |
4002 | */ | |
36c8b586 | 4003 | int task_nice(const struct task_struct *p) |
1da177e4 LT |
4004 | { |
4005 | return TASK_NICE(p); | |
4006 | } | |
1da177e4 | 4007 | EXPORT_SYMBOL_GPL(task_nice); |
1da177e4 LT |
4008 | |
4009 | /** | |
4010 | * idle_cpu - is a given cpu idle currently? | |
4011 | * @cpu: the processor in question. | |
4012 | */ | |
4013 | int idle_cpu(int cpu) | |
4014 | { | |
4015 | return cpu_curr(cpu) == cpu_rq(cpu)->idle; | |
4016 | } | |
4017 | ||
1da177e4 LT |
4018 | /** |
4019 | * idle_task - return the idle task for a given cpu. | |
4020 | * @cpu: the processor in question. | |
4021 | */ | |
36c8b586 | 4022 | struct task_struct *idle_task(int cpu) |
1da177e4 LT |
4023 | { |
4024 | return cpu_rq(cpu)->idle; | |
4025 | } | |
4026 | ||
4027 | /** | |
4028 | * find_process_by_pid - find a process with a matching PID value. | |
4029 | * @pid: the pid in question. | |
4030 | */ | |
a9957449 | 4031 | static struct task_struct *find_process_by_pid(pid_t pid) |
1da177e4 LT |
4032 | { |
4033 | return pid ? find_task_by_pid(pid) : current; | |
4034 | } | |
4035 | ||
4036 | /* Actually do priority change: must hold rq lock. */ | |
dd41f596 IM |
4037 | static void |
4038 | __setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio) | |
1da177e4 | 4039 | { |
dd41f596 | 4040 | BUG_ON(p->se.on_rq); |
48f24c4d | 4041 | |
1da177e4 | 4042 | p->policy = policy; |
dd41f596 IM |
4043 | switch (p->policy) { |
4044 | case SCHED_NORMAL: | |
4045 | case SCHED_BATCH: | |
4046 | case SCHED_IDLE: | |
4047 | p->sched_class = &fair_sched_class; | |
4048 | break; | |
4049 | case SCHED_FIFO: | |
4050 | case SCHED_RR: | |
4051 | p->sched_class = &rt_sched_class; | |
4052 | break; | |
4053 | } | |
4054 | ||
1da177e4 | 4055 | p->rt_priority = prio; |
b29739f9 IM |
4056 | p->normal_prio = normal_prio(p); |
4057 | /* we are holding p->pi_lock already */ | |
4058 | p->prio = rt_mutex_getprio(p); | |
2dd73a4f | 4059 | set_load_weight(p); |
1da177e4 LT |
4060 | } |
4061 | ||
4062 | /** | |
72fd4a35 | 4063 | * sched_setscheduler - change the scheduling policy and/or RT priority of a thread. |
1da177e4 LT |
4064 | * @p: the task in question. |
4065 | * @policy: new policy. | |
4066 | * @param: structure containing the new RT priority. | |
5fe1d75f | 4067 | * |
72fd4a35 | 4068 | * NOTE that the task may be already dead. |
1da177e4 | 4069 | */ |
95cdf3b7 IM |
4070 | int sched_setscheduler(struct task_struct *p, int policy, |
4071 | struct sched_param *param) | |
1da177e4 | 4072 | { |
83b699ed | 4073 | int retval, oldprio, oldpolicy = -1, on_rq, running; |
1da177e4 | 4074 | unsigned long flags; |
70b97a7f | 4075 | struct rq *rq; |
1da177e4 | 4076 | |
66e5393a SR |
4077 | /* may grab non-irq protected spin_locks */ |
4078 | BUG_ON(in_interrupt()); | |
1da177e4 LT |
4079 | recheck: |
4080 | /* double check policy once rq lock held */ | |
4081 | if (policy < 0) | |
4082 | policy = oldpolicy = p->policy; | |
4083 | else if (policy != SCHED_FIFO && policy != SCHED_RR && | |
dd41f596 IM |
4084 | policy != SCHED_NORMAL && policy != SCHED_BATCH && |
4085 | policy != SCHED_IDLE) | |
b0a9499c | 4086 | return -EINVAL; |
1da177e4 LT |
4087 | /* |
4088 | * Valid priorities for SCHED_FIFO and SCHED_RR are | |
dd41f596 IM |
4089 | * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL, |
4090 | * SCHED_BATCH and SCHED_IDLE is 0. | |
1da177e4 LT |
4091 | */ |
4092 | if (param->sched_priority < 0 || | |
95cdf3b7 | 4093 | (p->mm && param->sched_priority > MAX_USER_RT_PRIO-1) || |
d46523ea | 4094 | (!p->mm && param->sched_priority > MAX_RT_PRIO-1)) |
1da177e4 | 4095 | return -EINVAL; |
e05606d3 | 4096 | if (rt_policy(policy) != (param->sched_priority != 0)) |
1da177e4 LT |
4097 | return -EINVAL; |
4098 | ||
37e4ab3f OC |
4099 | /* |
4100 | * Allow unprivileged RT tasks to decrease priority: | |
4101 | */ | |
4102 | if (!capable(CAP_SYS_NICE)) { | |
e05606d3 | 4103 | if (rt_policy(policy)) { |
8dc3e909 | 4104 | unsigned long rlim_rtprio; |
8dc3e909 ON |
4105 | |
4106 | if (!lock_task_sighand(p, &flags)) | |
4107 | return -ESRCH; | |
4108 | rlim_rtprio = p->signal->rlim[RLIMIT_RTPRIO].rlim_cur; | |
4109 | unlock_task_sighand(p, &flags); | |
4110 | ||
4111 | /* can't set/change the rt policy */ | |
4112 | if (policy != p->policy && !rlim_rtprio) | |
4113 | return -EPERM; | |
4114 | ||
4115 | /* can't increase priority */ | |
4116 | if (param->sched_priority > p->rt_priority && | |
4117 | param->sched_priority > rlim_rtprio) | |
4118 | return -EPERM; | |
4119 | } | |
dd41f596 IM |
4120 | /* |
4121 | * Like positive nice levels, dont allow tasks to | |
4122 | * move out of SCHED_IDLE either: | |
4123 | */ | |
4124 | if (p->policy == SCHED_IDLE && policy != SCHED_IDLE) | |
4125 | return -EPERM; | |
5fe1d75f | 4126 | |
37e4ab3f OC |
4127 | /* can't change other user's priorities */ |
4128 | if ((current->euid != p->euid) && | |
4129 | (current->euid != p->uid)) | |
4130 | return -EPERM; | |
4131 | } | |
1da177e4 LT |
4132 | |
4133 | retval = security_task_setscheduler(p, policy, param); | |
4134 | if (retval) | |
4135 | return retval; | |
b29739f9 IM |
4136 | /* |
4137 | * make sure no PI-waiters arrive (or leave) while we are | |
4138 | * changing the priority of the task: | |
4139 | */ | |
4140 | spin_lock_irqsave(&p->pi_lock, flags); | |
1da177e4 LT |
4141 | /* |
4142 | * To be able to change p->policy safely, the apropriate | |
4143 | * runqueue lock must be held. | |
4144 | */ | |
b29739f9 | 4145 | rq = __task_rq_lock(p); |
1da177e4 LT |
4146 | /* recheck policy now with rq lock held */ |
4147 | if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) { | |
4148 | policy = oldpolicy = -1; | |
b29739f9 IM |
4149 | __task_rq_unlock(rq); |
4150 | spin_unlock_irqrestore(&p->pi_lock, flags); | |
1da177e4 LT |
4151 | goto recheck; |
4152 | } | |
2daa3577 | 4153 | update_rq_clock(rq); |
dd41f596 | 4154 | on_rq = p->se.on_rq; |
83b699ed SV |
4155 | running = task_running(rq, p); |
4156 | if (on_rq) { | |
2e1cb74a | 4157 | deactivate_task(rq, p, 0); |
83b699ed SV |
4158 | if (running) |
4159 | p->sched_class->put_prev_task(rq, p); | |
4160 | } | |
f6b53205 | 4161 | |
1da177e4 | 4162 | oldprio = p->prio; |
dd41f596 | 4163 | __setscheduler(rq, p, policy, param->sched_priority); |
f6b53205 | 4164 | |
dd41f596 | 4165 | if (on_rq) { |
83b699ed SV |
4166 | if (running) |
4167 | p->sched_class->set_curr_task(rq); | |
dd41f596 | 4168 | activate_task(rq, p, 0); |
1da177e4 LT |
4169 | /* |
4170 | * Reschedule if we are currently running on this runqueue and | |
d5f9f942 AM |
4171 | * our priority decreased, or if we are not currently running on |
4172 | * this runqueue and our priority is higher than the current's | |
1da177e4 | 4173 | */ |
83b699ed | 4174 | if (running) { |
d5f9f942 AM |
4175 | if (p->prio > oldprio) |
4176 | resched_task(rq->curr); | |
dd41f596 IM |
4177 | } else { |
4178 | check_preempt_curr(rq, p); | |
4179 | } | |
1da177e4 | 4180 | } |
b29739f9 IM |
4181 | __task_rq_unlock(rq); |
4182 | spin_unlock_irqrestore(&p->pi_lock, flags); | |
4183 | ||
95e02ca9 TG |
4184 | rt_mutex_adjust_pi(p); |
4185 | ||
1da177e4 LT |
4186 | return 0; |
4187 | } | |
4188 | EXPORT_SYMBOL_GPL(sched_setscheduler); | |
4189 | ||
95cdf3b7 IM |
4190 | static int |
4191 | do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param) | |
1da177e4 | 4192 | { |
1da177e4 LT |
4193 | struct sched_param lparam; |
4194 | struct task_struct *p; | |
36c8b586 | 4195 | int retval; |
1da177e4 LT |
4196 | |
4197 | if (!param || pid < 0) | |
4198 | return -EINVAL; | |
4199 | if (copy_from_user(&lparam, param, sizeof(struct sched_param))) | |
4200 | return -EFAULT; | |
5fe1d75f ON |
4201 | |
4202 | rcu_read_lock(); | |
4203 | retval = -ESRCH; | |
1da177e4 | 4204 | p = find_process_by_pid(pid); |
5fe1d75f ON |
4205 | if (p != NULL) |
4206 | retval = sched_setscheduler(p, policy, &lparam); | |
4207 | rcu_read_unlock(); | |
36c8b586 | 4208 | |
1da177e4 LT |
4209 | return retval; |
4210 | } | |
4211 | ||
4212 | /** | |
4213 | * sys_sched_setscheduler - set/change the scheduler policy and RT priority | |
4214 | * @pid: the pid in question. | |
4215 | * @policy: new policy. | |
4216 | * @param: structure containing the new RT priority. | |
4217 | */ | |
4218 | asmlinkage long sys_sched_setscheduler(pid_t pid, int policy, | |
4219 | struct sched_param __user *param) | |
4220 | { | |
c21761f1 JB |
4221 | /* negative values for policy are not valid */ |
4222 | if (policy < 0) | |
4223 | return -EINVAL; | |
4224 | ||
1da177e4 LT |
4225 | return do_sched_setscheduler(pid, policy, param); |
4226 | } | |
4227 | ||
4228 | /** | |
4229 | * sys_sched_setparam - set/change the RT priority of a thread | |
4230 | * @pid: the pid in question. | |
4231 | * @param: structure containing the new RT priority. | |
4232 | */ | |
4233 | asmlinkage long sys_sched_setparam(pid_t pid, struct sched_param __user *param) | |
4234 | { | |
4235 | return do_sched_setscheduler(pid, -1, param); | |
4236 | } | |
4237 | ||
4238 | /** | |
4239 | * sys_sched_getscheduler - get the policy (scheduling class) of a thread | |
4240 | * @pid: the pid in question. | |
4241 | */ | |
4242 | asmlinkage long sys_sched_getscheduler(pid_t pid) | |
4243 | { | |
36c8b586 | 4244 | struct task_struct *p; |
3a5c359a | 4245 | int retval; |
1da177e4 LT |
4246 | |
4247 | if (pid < 0) | |
3a5c359a | 4248 | return -EINVAL; |
1da177e4 LT |
4249 | |
4250 | retval = -ESRCH; | |
4251 | read_lock(&tasklist_lock); | |
4252 | p = find_process_by_pid(pid); | |
4253 | if (p) { | |
4254 | retval = security_task_getscheduler(p); | |
4255 | if (!retval) | |
4256 | retval = p->policy; | |
4257 | } | |
4258 | read_unlock(&tasklist_lock); | |
1da177e4 LT |
4259 | return retval; |
4260 | } | |
4261 | ||
4262 | /** | |
4263 | * sys_sched_getscheduler - get the RT priority of a thread | |
4264 | * @pid: the pid in question. | |
4265 | * @param: structure containing the RT priority. | |
4266 | */ | |
4267 | asmlinkage long sys_sched_getparam(pid_t pid, struct sched_param __user *param) | |
4268 | { | |
4269 | struct sched_param lp; | |
36c8b586 | 4270 | struct task_struct *p; |
3a5c359a | 4271 | int retval; |
1da177e4 LT |
4272 | |
4273 | if (!param || pid < 0) | |
3a5c359a | 4274 | return -EINVAL; |
1da177e4 LT |
4275 | |
4276 | read_lock(&tasklist_lock); | |
4277 | p = find_process_by_pid(pid); | |
4278 | retval = -ESRCH; | |
4279 | if (!p) | |
4280 | goto out_unlock; | |
4281 | ||
4282 | retval = security_task_getscheduler(p); | |
4283 | if (retval) | |
4284 | goto out_unlock; | |
4285 | ||
4286 | lp.sched_priority = p->rt_priority; | |
4287 | read_unlock(&tasklist_lock); | |
4288 | ||
4289 | /* | |
4290 | * This one might sleep, we cannot do it with a spinlock held ... | |
4291 | */ | |
4292 | retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0; | |
4293 | ||
1da177e4 LT |
4294 | return retval; |
4295 | ||
4296 | out_unlock: | |
4297 | read_unlock(&tasklist_lock); | |
4298 | return retval; | |
4299 | } | |
4300 | ||
4301 | long sched_setaffinity(pid_t pid, cpumask_t new_mask) | |
4302 | { | |
1da177e4 | 4303 | cpumask_t cpus_allowed; |
36c8b586 IM |
4304 | struct task_struct *p; |
4305 | int retval; | |
1da177e4 | 4306 | |
5be9361c | 4307 | mutex_lock(&sched_hotcpu_mutex); |
1da177e4 LT |
4308 | read_lock(&tasklist_lock); |
4309 | ||
4310 | p = find_process_by_pid(pid); | |
4311 | if (!p) { | |
4312 | read_unlock(&tasklist_lock); | |
5be9361c | 4313 | mutex_unlock(&sched_hotcpu_mutex); |
1da177e4 LT |
4314 | return -ESRCH; |
4315 | } | |
4316 | ||
4317 | /* | |
4318 | * It is not safe to call set_cpus_allowed with the | |
4319 | * tasklist_lock held. We will bump the task_struct's | |
4320 | * usage count and then drop tasklist_lock. | |
4321 | */ | |
4322 | get_task_struct(p); | |
4323 | read_unlock(&tasklist_lock); | |
4324 | ||
4325 | retval = -EPERM; | |
4326 | if ((current->euid != p->euid) && (current->euid != p->uid) && | |
4327 | !capable(CAP_SYS_NICE)) | |
4328 | goto out_unlock; | |
4329 | ||
e7834f8f DQ |
4330 | retval = security_task_setscheduler(p, 0, NULL); |
4331 | if (retval) | |
4332 | goto out_unlock; | |
4333 | ||
1da177e4 LT |
4334 | cpus_allowed = cpuset_cpus_allowed(p); |
4335 | cpus_and(new_mask, new_mask, cpus_allowed); | |
4336 | retval = set_cpus_allowed(p, new_mask); | |
4337 | ||
4338 | out_unlock: | |
4339 | put_task_struct(p); | |
5be9361c | 4340 | mutex_unlock(&sched_hotcpu_mutex); |
1da177e4 LT |
4341 | return retval; |
4342 | } | |
4343 | ||
4344 | static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len, | |
4345 | cpumask_t *new_mask) | |
4346 | { | |
4347 | if (len < sizeof(cpumask_t)) { | |
4348 | memset(new_mask, 0, sizeof(cpumask_t)); | |
4349 | } else if (len > sizeof(cpumask_t)) { | |
4350 | len = sizeof(cpumask_t); | |
4351 | } | |
4352 | return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0; | |
4353 | } | |
4354 | ||
4355 | /** | |
4356 | * sys_sched_setaffinity - set the cpu affinity of a process | |
4357 | * @pid: pid of the process | |
4358 | * @len: length in bytes of the bitmask pointed to by user_mask_ptr | |
4359 | * @user_mask_ptr: user-space pointer to the new cpu mask | |
4360 | */ | |
4361 | asmlinkage long sys_sched_setaffinity(pid_t pid, unsigned int len, | |
4362 | unsigned long __user *user_mask_ptr) | |
4363 | { | |
4364 | cpumask_t new_mask; | |
4365 | int retval; | |
4366 | ||
4367 | retval = get_user_cpu_mask(user_mask_ptr, len, &new_mask); | |
4368 | if (retval) | |
4369 | return retval; | |
4370 | ||
4371 | return sched_setaffinity(pid, new_mask); | |
4372 | } | |
4373 | ||
4374 | /* | |
4375 | * Represents all cpu's present in the system | |
4376 | * In systems capable of hotplug, this map could dynamically grow | |
4377 | * as new cpu's are detected in the system via any platform specific | |
4378 | * method, such as ACPI for e.g. | |
4379 | */ | |
4380 | ||
4cef0c61 | 4381 | cpumask_t cpu_present_map __read_mostly; |
1da177e4 LT |
4382 | EXPORT_SYMBOL(cpu_present_map); |
4383 | ||
4384 | #ifndef CONFIG_SMP | |
4cef0c61 | 4385 | cpumask_t cpu_online_map __read_mostly = CPU_MASK_ALL; |
e16b38f7 GB |
4386 | EXPORT_SYMBOL(cpu_online_map); |
4387 | ||
4cef0c61 | 4388 | cpumask_t cpu_possible_map __read_mostly = CPU_MASK_ALL; |
e16b38f7 | 4389 | EXPORT_SYMBOL(cpu_possible_map); |
1da177e4 LT |
4390 | #endif |
4391 | ||
4392 | long sched_getaffinity(pid_t pid, cpumask_t *mask) | |
4393 | { | |
36c8b586 | 4394 | struct task_struct *p; |
1da177e4 | 4395 | int retval; |
1da177e4 | 4396 | |
5be9361c | 4397 | mutex_lock(&sched_hotcpu_mutex); |
1da177e4 LT |
4398 | read_lock(&tasklist_lock); |
4399 | ||
4400 | retval = -ESRCH; | |
4401 | p = find_process_by_pid(pid); | |
4402 | if (!p) | |
4403 | goto out_unlock; | |
4404 | ||
e7834f8f DQ |
4405 | retval = security_task_getscheduler(p); |
4406 | if (retval) | |
4407 | goto out_unlock; | |
4408 | ||
2f7016d9 | 4409 | cpus_and(*mask, p->cpus_allowed, cpu_online_map); |
1da177e4 LT |
4410 | |
4411 | out_unlock: | |
4412 | read_unlock(&tasklist_lock); | |
5be9361c | 4413 | mutex_unlock(&sched_hotcpu_mutex); |
1da177e4 | 4414 | |
9531b62f | 4415 | return retval; |
1da177e4 LT |
4416 | } |
4417 | ||
4418 | /** | |
4419 | * sys_sched_getaffinity - get the cpu affinity of a process | |
4420 | * @pid: pid of the process | |
4421 | * @len: length in bytes of the bitmask pointed to by user_mask_ptr | |
4422 | * @user_mask_ptr: user-space pointer to hold the current cpu mask | |
4423 | */ | |
4424 | asmlinkage long sys_sched_getaffinity(pid_t pid, unsigned int len, | |
4425 | unsigned long __user *user_mask_ptr) | |
4426 | { | |
4427 | int ret; | |
4428 | cpumask_t mask; | |
4429 | ||
4430 | if (len < sizeof(cpumask_t)) | |
4431 | return -EINVAL; | |
4432 | ||
4433 | ret = sched_getaffinity(pid, &mask); | |
4434 | if (ret < 0) | |
4435 | return ret; | |
4436 | ||
4437 | if (copy_to_user(user_mask_ptr, &mask, sizeof(cpumask_t))) | |
4438 | return -EFAULT; | |
4439 | ||
4440 | return sizeof(cpumask_t); | |
4441 | } | |
4442 | ||
4443 | /** | |
4444 | * sys_sched_yield - yield the current processor to other threads. | |
4445 | * | |
dd41f596 IM |
4446 | * This function yields the current CPU to other tasks. If there are no |
4447 | * other threads running on this CPU then this function will return. | |
1da177e4 LT |
4448 | */ |
4449 | asmlinkage long sys_sched_yield(void) | |
4450 | { | |
70b97a7f | 4451 | struct rq *rq = this_rq_lock(); |
1da177e4 | 4452 | |
2d72376b | 4453 | schedstat_inc(rq, yld_count); |
4530d7ab | 4454 | current->sched_class->yield_task(rq); |
1da177e4 LT |
4455 | |
4456 | /* | |
4457 | * Since we are going to call schedule() anyway, there's | |
4458 | * no need to preempt or enable interrupts: | |
4459 | */ | |
4460 | __release(rq->lock); | |
8a25d5de | 4461 | spin_release(&rq->lock.dep_map, 1, _THIS_IP_); |
1da177e4 LT |
4462 | _raw_spin_unlock(&rq->lock); |
4463 | preempt_enable_no_resched(); | |
4464 | ||
4465 | schedule(); | |
4466 | ||
4467 | return 0; | |
4468 | } | |
4469 | ||
e7b38404 | 4470 | static void __cond_resched(void) |
1da177e4 | 4471 | { |
8e0a43d8 IM |
4472 | #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP |
4473 | __might_sleep(__FILE__, __LINE__); | |
4474 | #endif | |
5bbcfd90 IM |
4475 | /* |
4476 | * The BKS might be reacquired before we have dropped | |
4477 | * PREEMPT_ACTIVE, which could trigger a second | |
4478 | * cond_resched() call. | |
4479 | */ | |
1da177e4 LT |
4480 | do { |
4481 | add_preempt_count(PREEMPT_ACTIVE); | |
4482 | schedule(); | |
4483 | sub_preempt_count(PREEMPT_ACTIVE); | |
4484 | } while (need_resched()); | |
4485 | } | |
4486 | ||
4487 | int __sched cond_resched(void) | |
4488 | { | |
9414232f IM |
4489 | if (need_resched() && !(preempt_count() & PREEMPT_ACTIVE) && |
4490 | system_state == SYSTEM_RUNNING) { | |
1da177e4 LT |
4491 | __cond_resched(); |
4492 | return 1; | |
4493 | } | |
4494 | return 0; | |
4495 | } | |
1da177e4 LT |
4496 | EXPORT_SYMBOL(cond_resched); |
4497 | ||
4498 | /* | |
4499 | * cond_resched_lock() - if a reschedule is pending, drop the given lock, | |
4500 | * call schedule, and on return reacquire the lock. | |
4501 | * | |
4502 | * This works OK both with and without CONFIG_PREEMPT. We do strange low-level | |
4503 | * operations here to prevent schedule() from being called twice (once via | |
4504 | * spin_unlock(), once by hand). | |
4505 | */ | |
95cdf3b7 | 4506 | int cond_resched_lock(spinlock_t *lock) |
1da177e4 | 4507 | { |
6df3cecb JK |
4508 | int ret = 0; |
4509 | ||
1da177e4 LT |
4510 | if (need_lockbreak(lock)) { |
4511 | spin_unlock(lock); | |
4512 | cpu_relax(); | |
6df3cecb | 4513 | ret = 1; |
1da177e4 LT |
4514 | spin_lock(lock); |
4515 | } | |
9414232f | 4516 | if (need_resched() && system_state == SYSTEM_RUNNING) { |
8a25d5de | 4517 | spin_release(&lock->dep_map, 1, _THIS_IP_); |
1da177e4 LT |
4518 | _raw_spin_unlock(lock); |
4519 | preempt_enable_no_resched(); | |
4520 | __cond_resched(); | |
6df3cecb | 4521 | ret = 1; |
1da177e4 | 4522 | spin_lock(lock); |
1da177e4 | 4523 | } |
6df3cecb | 4524 | return ret; |
1da177e4 | 4525 | } |
1da177e4 LT |
4526 | EXPORT_SYMBOL(cond_resched_lock); |
4527 | ||
4528 | int __sched cond_resched_softirq(void) | |
4529 | { | |
4530 | BUG_ON(!in_softirq()); | |
4531 | ||
9414232f | 4532 | if (need_resched() && system_state == SYSTEM_RUNNING) { |
98d82567 | 4533 | local_bh_enable(); |
1da177e4 LT |
4534 | __cond_resched(); |
4535 | local_bh_disable(); | |
4536 | return 1; | |
4537 | } | |
4538 | return 0; | |
4539 | } | |
1da177e4 LT |
4540 | EXPORT_SYMBOL(cond_resched_softirq); |
4541 | ||
1da177e4 LT |
4542 | /** |
4543 | * yield - yield the current processor to other threads. | |
4544 | * | |
72fd4a35 | 4545 | * This is a shortcut for kernel-space yielding - it marks the |
1da177e4 LT |
4546 | * thread runnable and calls sys_sched_yield(). |
4547 | */ | |
4548 | void __sched yield(void) | |
4549 | { | |
4550 | set_current_state(TASK_RUNNING); | |
4551 | sys_sched_yield(); | |
4552 | } | |
1da177e4 LT |
4553 | EXPORT_SYMBOL(yield); |
4554 | ||
4555 | /* | |
4556 | * This task is about to go to sleep on IO. Increment rq->nr_iowait so | |
4557 | * that process accounting knows that this is a task in IO wait state. | |
4558 | * | |
4559 | * But don't do that if it is a deliberate, throttling IO wait (this task | |
4560 | * has set its backing_dev_info: the queue against which it should throttle) | |
4561 | */ | |
4562 | void __sched io_schedule(void) | |
4563 | { | |
70b97a7f | 4564 | struct rq *rq = &__raw_get_cpu_var(runqueues); |
1da177e4 | 4565 | |
0ff92245 | 4566 | delayacct_blkio_start(); |
1da177e4 LT |
4567 | atomic_inc(&rq->nr_iowait); |
4568 | schedule(); | |
4569 | atomic_dec(&rq->nr_iowait); | |
0ff92245 | 4570 | delayacct_blkio_end(); |
1da177e4 | 4571 | } |
1da177e4 LT |
4572 | EXPORT_SYMBOL(io_schedule); |
4573 | ||
4574 | long __sched io_schedule_timeout(long timeout) | |
4575 | { | |
70b97a7f | 4576 | struct rq *rq = &__raw_get_cpu_var(runqueues); |
1da177e4 LT |
4577 | long ret; |
4578 | ||
0ff92245 | 4579 | delayacct_blkio_start(); |
1da177e4 LT |
4580 | atomic_inc(&rq->nr_iowait); |
4581 | ret = schedule_timeout(timeout); | |
4582 | atomic_dec(&rq->nr_iowait); | |
0ff92245 | 4583 | delayacct_blkio_end(); |
1da177e4 LT |
4584 | return ret; |
4585 | } | |
4586 | ||
4587 | /** | |
4588 | * sys_sched_get_priority_max - return maximum RT priority. | |
4589 | * @policy: scheduling class. | |
4590 | * | |
4591 | * this syscall returns the maximum rt_priority that can be used | |
4592 | * by a given scheduling class. | |
4593 | */ | |
4594 | asmlinkage long sys_sched_get_priority_max(int policy) | |
4595 | { | |
4596 | int ret = -EINVAL; | |
4597 | ||
4598 | switch (policy) { | |
4599 | case SCHED_FIFO: | |
4600 | case SCHED_RR: | |
4601 | ret = MAX_USER_RT_PRIO-1; | |
4602 | break; | |
4603 | case SCHED_NORMAL: | |
b0a9499c | 4604 | case SCHED_BATCH: |
dd41f596 | 4605 | case SCHED_IDLE: |
1da177e4 LT |
4606 | ret = 0; |
4607 | break; | |
4608 | } | |
4609 | return ret; | |
4610 | } | |
4611 | ||
4612 | /** | |
4613 | * sys_sched_get_priority_min - return minimum RT priority. | |
4614 | * @policy: scheduling class. | |
4615 | * | |
4616 | * this syscall returns the minimum rt_priority that can be used | |
4617 | * by a given scheduling class. | |
4618 | */ | |
4619 | asmlinkage long sys_sched_get_priority_min(int policy) | |
4620 | { | |
4621 | int ret = -EINVAL; | |
4622 | ||
4623 | switch (policy) { | |
4624 | case SCHED_FIFO: | |
4625 | case SCHED_RR: | |
4626 | ret = 1; | |
4627 | break; | |
4628 | case SCHED_NORMAL: | |
b0a9499c | 4629 | case SCHED_BATCH: |
dd41f596 | 4630 | case SCHED_IDLE: |
1da177e4 LT |
4631 | ret = 0; |
4632 | } | |
4633 | return ret; | |
4634 | } | |
4635 | ||
4636 | /** | |
4637 | * sys_sched_rr_get_interval - return the default timeslice of a process. | |
4638 | * @pid: pid of the process. | |
4639 | * @interval: userspace pointer to the timeslice value. | |
4640 | * | |
4641 | * this syscall writes the default timeslice value of a given process | |
4642 | * into the user-space timespec buffer. A value of '0' means infinity. | |
4643 | */ | |
4644 | asmlinkage | |
4645 | long sys_sched_rr_get_interval(pid_t pid, struct timespec __user *interval) | |
4646 | { | |
36c8b586 | 4647 | struct task_struct *p; |
a4ec24b4 | 4648 | unsigned int time_slice; |
3a5c359a | 4649 | int retval; |
1da177e4 | 4650 | struct timespec t; |
1da177e4 LT |
4651 | |
4652 | if (pid < 0) | |
3a5c359a | 4653 | return -EINVAL; |
1da177e4 LT |
4654 | |
4655 | retval = -ESRCH; | |
4656 | read_lock(&tasklist_lock); | |
4657 | p = find_process_by_pid(pid); | |
4658 | if (!p) | |
4659 | goto out_unlock; | |
4660 | ||
4661 | retval = security_task_getscheduler(p); | |
4662 | if (retval) | |
4663 | goto out_unlock; | |
4664 | ||
a4ec24b4 DA |
4665 | if (p->policy == SCHED_FIFO) |
4666 | time_slice = 0; | |
4667 | else if (p->policy == SCHED_RR) | |
4668 | time_slice = DEF_TIMESLICE; | |
4669 | else { | |
4670 | struct sched_entity *se = &p->se; | |
4671 | unsigned long flags; | |
4672 | struct rq *rq; | |
4673 | ||
4674 | rq = task_rq_lock(p, &flags); | |
4675 | time_slice = NS_TO_JIFFIES(sched_slice(cfs_rq_of(se), se)); | |
4676 | task_rq_unlock(rq, &flags); | |
4677 | } | |
1da177e4 | 4678 | read_unlock(&tasklist_lock); |
a4ec24b4 | 4679 | jiffies_to_timespec(time_slice, &t); |
1da177e4 | 4680 | retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0; |
1da177e4 | 4681 | return retval; |
3a5c359a | 4682 | |
1da177e4 LT |
4683 | out_unlock: |
4684 | read_unlock(&tasklist_lock); | |
4685 | return retval; | |
4686 | } | |
4687 | ||
2ed6e34f | 4688 | static const char stat_nam[] = "RSDTtZX"; |
36c8b586 IM |
4689 | |
4690 | static void show_task(struct task_struct *p) | |
1da177e4 | 4691 | { |
1da177e4 | 4692 | unsigned long free = 0; |
36c8b586 | 4693 | unsigned state; |
1da177e4 | 4694 | |
1da177e4 | 4695 | state = p->state ? __ffs(p->state) + 1 : 0; |
2ed6e34f AM |
4696 | printk("%-13.13s %c", p->comm, |
4697 | state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?'); | |
4bd77321 | 4698 | #if BITS_PER_LONG == 32 |
1da177e4 | 4699 | if (state == TASK_RUNNING) |
4bd77321 | 4700 | printk(" running "); |
1da177e4 | 4701 | else |
4bd77321 | 4702 | printk(" %08lx ", thread_saved_pc(p)); |
1da177e4 LT |
4703 | #else |
4704 | if (state == TASK_RUNNING) | |
4bd77321 | 4705 | printk(" running task "); |
1da177e4 LT |
4706 | else |
4707 | printk(" %016lx ", thread_saved_pc(p)); | |
4708 | #endif | |
4709 | #ifdef CONFIG_DEBUG_STACK_USAGE | |
4710 | { | |
10ebffde | 4711 | unsigned long *n = end_of_stack(p); |
1da177e4 LT |
4712 | while (!*n) |
4713 | n++; | |
10ebffde | 4714 | free = (unsigned long)n - (unsigned long)end_of_stack(p); |
1da177e4 LT |
4715 | } |
4716 | #endif | |
4bd77321 | 4717 | printk("%5lu %5d %6d\n", free, p->pid, p->parent->pid); |
1da177e4 LT |
4718 | |
4719 | if (state != TASK_RUNNING) | |
4720 | show_stack(p, NULL); | |
4721 | } | |
4722 | ||
e59e2ae2 | 4723 | void show_state_filter(unsigned long state_filter) |
1da177e4 | 4724 | { |
36c8b586 | 4725 | struct task_struct *g, *p; |
1da177e4 | 4726 | |
4bd77321 IM |
4727 | #if BITS_PER_LONG == 32 |
4728 | printk(KERN_INFO | |
4729 | " task PC stack pid father\n"); | |
1da177e4 | 4730 | #else |
4bd77321 IM |
4731 | printk(KERN_INFO |
4732 | " task PC stack pid father\n"); | |
1da177e4 LT |
4733 | #endif |
4734 | read_lock(&tasklist_lock); | |
4735 | do_each_thread(g, p) { | |
4736 | /* | |
4737 | * reset the NMI-timeout, listing all files on a slow | |
4738 | * console might take alot of time: | |
4739 | */ | |
4740 | touch_nmi_watchdog(); | |
39bc89fd | 4741 | if (!state_filter || (p->state & state_filter)) |
e59e2ae2 | 4742 | show_task(p); |
1da177e4 LT |
4743 | } while_each_thread(g, p); |
4744 | ||
04c9167f JF |
4745 | touch_all_softlockup_watchdogs(); |
4746 | ||
dd41f596 IM |
4747 | #ifdef CONFIG_SCHED_DEBUG |
4748 | sysrq_sched_debug_show(); | |
4749 | #endif | |
1da177e4 | 4750 | read_unlock(&tasklist_lock); |
e59e2ae2 IM |
4751 | /* |
4752 | * Only show locks if all tasks are dumped: | |
4753 | */ | |
4754 | if (state_filter == -1) | |
4755 | debug_show_all_locks(); | |
1da177e4 LT |
4756 | } |
4757 | ||
1df21055 IM |
4758 | void __cpuinit init_idle_bootup_task(struct task_struct *idle) |
4759 | { | |
dd41f596 | 4760 | idle->sched_class = &idle_sched_class; |
1df21055 IM |
4761 | } |
4762 | ||
f340c0d1 IM |
4763 | /** |
4764 | * init_idle - set up an idle thread for a given CPU | |
4765 | * @idle: task in question | |
4766 | * @cpu: cpu the idle task belongs to | |
4767 | * | |
4768 | * NOTE: this function does not set the idle thread's NEED_RESCHED | |
4769 | * flag, to make booting more robust. | |
4770 | */ | |
5c1e1767 | 4771 | void __cpuinit init_idle(struct task_struct *idle, int cpu) |
1da177e4 | 4772 | { |
70b97a7f | 4773 | struct rq *rq = cpu_rq(cpu); |
1da177e4 LT |
4774 | unsigned long flags; |
4775 | ||
dd41f596 IM |
4776 | __sched_fork(idle); |
4777 | idle->se.exec_start = sched_clock(); | |
4778 | ||
b29739f9 | 4779 | idle->prio = idle->normal_prio = MAX_PRIO; |
1da177e4 | 4780 | idle->cpus_allowed = cpumask_of_cpu(cpu); |
dd41f596 | 4781 | __set_task_cpu(idle, cpu); |
1da177e4 LT |
4782 | |
4783 | spin_lock_irqsave(&rq->lock, flags); | |
4784 | rq->curr = rq->idle = idle; | |
4866cde0 NP |
4785 | #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW) |
4786 | idle->oncpu = 1; | |
4787 | #endif | |
1da177e4 LT |
4788 | spin_unlock_irqrestore(&rq->lock, flags); |
4789 | ||
4790 | /* Set the preempt count _outside_ the spinlocks! */ | |
4791 | #if defined(CONFIG_PREEMPT) && !defined(CONFIG_PREEMPT_BKL) | |
a1261f54 | 4792 | task_thread_info(idle)->preempt_count = (idle->lock_depth >= 0); |
1da177e4 | 4793 | #else |
a1261f54 | 4794 | task_thread_info(idle)->preempt_count = 0; |
1da177e4 | 4795 | #endif |
dd41f596 IM |
4796 | /* |
4797 | * The idle tasks have their own, simple scheduling class: | |
4798 | */ | |
4799 | idle->sched_class = &idle_sched_class; | |
1da177e4 LT |
4800 | } |
4801 | ||
4802 | /* | |
4803 | * In a system that switches off the HZ timer nohz_cpu_mask | |
4804 | * indicates which cpus entered this state. This is used | |
4805 | * in the rcu update to wait only for active cpus. For system | |
4806 | * which do not switch off the HZ timer nohz_cpu_mask should | |
4807 | * always be CPU_MASK_NONE. | |
4808 | */ | |
4809 | cpumask_t nohz_cpu_mask = CPU_MASK_NONE; | |
4810 | ||
4811 | #ifdef CONFIG_SMP | |
4812 | /* | |
4813 | * This is how migration works: | |
4814 | * | |
70b97a7f | 4815 | * 1) we queue a struct migration_req structure in the source CPU's |
1da177e4 LT |
4816 | * runqueue and wake up that CPU's migration thread. |
4817 | * 2) we down() the locked semaphore => thread blocks. | |
4818 | * 3) migration thread wakes up (implicitly it forces the migrated | |
4819 | * thread off the CPU) | |
4820 | * 4) it gets the migration request and checks whether the migrated | |
4821 | * task is still in the wrong runqueue. | |
4822 | * 5) if it's in the wrong runqueue then the migration thread removes | |
4823 | * it and puts it into the right queue. | |
4824 | * 6) migration thread up()s the semaphore. | |
4825 | * 7) we wake up and the migration is done. | |
4826 | */ | |
4827 | ||
4828 | /* | |
4829 | * Change a given task's CPU affinity. Migrate the thread to a | |
4830 | * proper CPU and schedule it away if the CPU it's executing on | |
4831 | * is removed from the allowed bitmask. | |
4832 | * | |
4833 | * NOTE: the caller must have a valid reference to the task, the | |
4834 | * task must not exit() & deallocate itself prematurely. The | |
4835 | * call is not atomic; no spinlocks may be held. | |
4836 | */ | |
36c8b586 | 4837 | int set_cpus_allowed(struct task_struct *p, cpumask_t new_mask) |
1da177e4 | 4838 | { |
70b97a7f | 4839 | struct migration_req req; |
1da177e4 | 4840 | unsigned long flags; |
70b97a7f | 4841 | struct rq *rq; |
48f24c4d | 4842 | int ret = 0; |
1da177e4 LT |
4843 | |
4844 | rq = task_rq_lock(p, &flags); | |
4845 | if (!cpus_intersects(new_mask, cpu_online_map)) { | |
4846 | ret = -EINVAL; | |
4847 | goto out; | |
4848 | } | |
4849 | ||
4850 | p->cpus_allowed = new_mask; | |
4851 | /* Can the task run on the task's current CPU? If so, we're done */ | |
4852 | if (cpu_isset(task_cpu(p), new_mask)) | |
4853 | goto out; | |
4854 | ||
4855 | if (migrate_task(p, any_online_cpu(new_mask), &req)) { | |
4856 | /* Need help from migration thread: drop lock and wait. */ | |
4857 | task_rq_unlock(rq, &flags); | |
4858 | wake_up_process(rq->migration_thread); | |
4859 | wait_for_completion(&req.done); | |
4860 | tlb_migrate_finish(p->mm); | |
4861 | return 0; | |
4862 | } | |
4863 | out: | |
4864 | task_rq_unlock(rq, &flags); | |
48f24c4d | 4865 | |
1da177e4 LT |
4866 | return ret; |
4867 | } | |
1da177e4 LT |
4868 | EXPORT_SYMBOL_GPL(set_cpus_allowed); |
4869 | ||
4870 | /* | |
4871 | * Move (not current) task off this cpu, onto dest cpu. We're doing | |
4872 | * this because either it can't run here any more (set_cpus_allowed() | |
4873 | * away from this CPU, or CPU going down), or because we're | |
4874 | * attempting to rebalance this task on exec (sched_exec). | |
4875 | * | |
4876 | * So we race with normal scheduler movements, but that's OK, as long | |
4877 | * as the task is no longer on this CPU. | |
efc30814 KK |
4878 | * |
4879 | * Returns non-zero if task was successfully migrated. | |
1da177e4 | 4880 | */ |
efc30814 | 4881 | static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu) |
1da177e4 | 4882 | { |
70b97a7f | 4883 | struct rq *rq_dest, *rq_src; |
dd41f596 | 4884 | int ret = 0, on_rq; |
1da177e4 LT |
4885 | |
4886 | if (unlikely(cpu_is_offline(dest_cpu))) | |
efc30814 | 4887 | return ret; |
1da177e4 LT |
4888 | |
4889 | rq_src = cpu_rq(src_cpu); | |
4890 | rq_dest = cpu_rq(dest_cpu); | |
4891 | ||
4892 | double_rq_lock(rq_src, rq_dest); | |
4893 | /* Already moved. */ | |
4894 | if (task_cpu(p) != src_cpu) | |
4895 | goto out; | |
4896 | /* Affinity changed (again). */ | |
4897 | if (!cpu_isset(dest_cpu, p->cpus_allowed)) | |
4898 | goto out; | |
4899 | ||
dd41f596 | 4900 | on_rq = p->se.on_rq; |
6e82a3be | 4901 | if (on_rq) |
2e1cb74a | 4902 | deactivate_task(rq_src, p, 0); |
6e82a3be | 4903 | |
1da177e4 | 4904 | set_task_cpu(p, dest_cpu); |
dd41f596 IM |
4905 | if (on_rq) { |
4906 | activate_task(rq_dest, p, 0); | |
4907 | check_preempt_curr(rq_dest, p); | |
1da177e4 | 4908 | } |
efc30814 | 4909 | ret = 1; |
1da177e4 LT |
4910 | out: |
4911 | double_rq_unlock(rq_src, rq_dest); | |
efc30814 | 4912 | return ret; |
1da177e4 LT |
4913 | } |
4914 | ||
4915 | /* | |
4916 | * migration_thread - this is a highprio system thread that performs | |
4917 | * thread migration by bumping thread off CPU then 'pushing' onto | |
4918 | * another runqueue. | |
4919 | */ | |
95cdf3b7 | 4920 | static int migration_thread(void *data) |
1da177e4 | 4921 | { |
1da177e4 | 4922 | int cpu = (long)data; |
70b97a7f | 4923 | struct rq *rq; |
1da177e4 LT |
4924 | |
4925 | rq = cpu_rq(cpu); | |
4926 | BUG_ON(rq->migration_thread != current); | |
4927 | ||
4928 | set_current_state(TASK_INTERRUPTIBLE); | |
4929 | while (!kthread_should_stop()) { | |
70b97a7f | 4930 | struct migration_req *req; |
1da177e4 | 4931 | struct list_head *head; |
1da177e4 | 4932 | |
1da177e4 LT |
4933 | spin_lock_irq(&rq->lock); |
4934 | ||
4935 | if (cpu_is_offline(cpu)) { | |
4936 | spin_unlock_irq(&rq->lock); | |
4937 | goto wait_to_die; | |
4938 | } | |
4939 | ||
4940 | if (rq->active_balance) { | |
4941 | active_load_balance(rq, cpu); | |
4942 | rq->active_balance = 0; | |
4943 | } | |
4944 | ||
4945 | head = &rq->migration_queue; | |
4946 | ||
4947 | if (list_empty(head)) { | |
4948 | spin_unlock_irq(&rq->lock); | |
4949 | schedule(); | |
4950 | set_current_state(TASK_INTERRUPTIBLE); | |
4951 | continue; | |
4952 | } | |
70b97a7f | 4953 | req = list_entry(head->next, struct migration_req, list); |
1da177e4 LT |
4954 | list_del_init(head->next); |
4955 | ||
674311d5 NP |
4956 | spin_unlock(&rq->lock); |
4957 | __migrate_task(req->task, cpu, req->dest_cpu); | |
4958 | local_irq_enable(); | |
1da177e4 LT |
4959 | |
4960 | complete(&req->done); | |
4961 | } | |
4962 | __set_current_state(TASK_RUNNING); | |
4963 | return 0; | |
4964 | ||
4965 | wait_to_die: | |
4966 | /* Wait for kthread_stop */ | |
4967 | set_current_state(TASK_INTERRUPTIBLE); | |
4968 | while (!kthread_should_stop()) { | |
4969 | schedule(); | |
4970 | set_current_state(TASK_INTERRUPTIBLE); | |
4971 | } | |
4972 | __set_current_state(TASK_RUNNING); | |
4973 | return 0; | |
4974 | } | |
4975 | ||
4976 | #ifdef CONFIG_HOTPLUG_CPU | |
054b9108 KK |
4977 | /* |
4978 | * Figure out where task on dead CPU should go, use force if neccessary. | |
4979 | * NOTE: interrupts should be disabled by the caller | |
4980 | */ | |
48f24c4d | 4981 | static void move_task_off_dead_cpu(int dead_cpu, struct task_struct *p) |
1da177e4 | 4982 | { |
efc30814 | 4983 | unsigned long flags; |
1da177e4 | 4984 | cpumask_t mask; |
70b97a7f IM |
4985 | struct rq *rq; |
4986 | int dest_cpu; | |
1da177e4 | 4987 | |
3a5c359a AK |
4988 | do { |
4989 | /* On same node? */ | |
4990 | mask = node_to_cpumask(cpu_to_node(dead_cpu)); | |
4991 | cpus_and(mask, mask, p->cpus_allowed); | |
4992 | dest_cpu = any_online_cpu(mask); | |
4993 | ||
4994 | /* On any allowed CPU? */ | |
4995 | if (dest_cpu == NR_CPUS) | |
4996 | dest_cpu = any_online_cpu(p->cpus_allowed); | |
4997 | ||
4998 | /* No more Mr. Nice Guy. */ | |
4999 | if (dest_cpu == NR_CPUS) { | |
5000 | rq = task_rq_lock(p, &flags); | |
5001 | cpus_setall(p->cpus_allowed); | |
5002 | dest_cpu = any_online_cpu(p->cpus_allowed); | |
5003 | task_rq_unlock(rq, &flags); | |
1da177e4 | 5004 | |
3a5c359a AK |
5005 | /* |
5006 | * Don't tell them about moving exiting tasks or | |
5007 | * kernel threads (both mm NULL), since they never | |
5008 | * leave kernel. | |
5009 | */ | |
5010 | if (p->mm && printk_ratelimit()) | |
5011 | printk(KERN_INFO "process %d (%s) no " | |
5012 | "longer affine to cpu%d\n", | |
5013 | p->pid, p->comm, dead_cpu); | |
5014 | } | |
5015 | } while (!__migrate_task(p, dead_cpu, dest_cpu)); | |
1da177e4 LT |
5016 | } |
5017 | ||
5018 | /* | |
5019 | * While a dead CPU has no uninterruptible tasks queued at this point, | |
5020 | * it might still have a nonzero ->nr_uninterruptible counter, because | |
5021 | * for performance reasons the counter is not stricly tracking tasks to | |
5022 | * their home CPUs. So we just add the counter to another CPU's counter, | |
5023 | * to keep the global sum constant after CPU-down: | |
5024 | */ | |
70b97a7f | 5025 | static void migrate_nr_uninterruptible(struct rq *rq_src) |
1da177e4 | 5026 | { |
70b97a7f | 5027 | struct rq *rq_dest = cpu_rq(any_online_cpu(CPU_MASK_ALL)); |
1da177e4 LT |
5028 | unsigned long flags; |
5029 | ||
5030 | local_irq_save(flags); | |
5031 | double_rq_lock(rq_src, rq_dest); | |
5032 | rq_dest->nr_uninterruptible += rq_src->nr_uninterruptible; | |
5033 | rq_src->nr_uninterruptible = 0; | |
5034 | double_rq_unlock(rq_src, rq_dest); | |
5035 | local_irq_restore(flags); | |
5036 | } | |
5037 | ||
5038 | /* Run through task list and migrate tasks from the dead cpu. */ | |
5039 | static void migrate_live_tasks(int src_cpu) | |
5040 | { | |
48f24c4d | 5041 | struct task_struct *p, *t; |
1da177e4 LT |
5042 | |
5043 | write_lock_irq(&tasklist_lock); | |
5044 | ||
48f24c4d IM |
5045 | do_each_thread(t, p) { |
5046 | if (p == current) | |
1da177e4 LT |
5047 | continue; |
5048 | ||
48f24c4d IM |
5049 | if (task_cpu(p) == src_cpu) |
5050 | move_task_off_dead_cpu(src_cpu, p); | |
5051 | } while_each_thread(t, p); | |
1da177e4 LT |
5052 | |
5053 | write_unlock_irq(&tasklist_lock); | |
5054 | } | |
5055 | ||
a9957449 AD |
5056 | /* |
5057 | * activate_idle_task - move idle task to the _front_ of runqueue. | |
5058 | */ | |
5059 | static void activate_idle_task(struct task_struct *p, struct rq *rq) | |
5060 | { | |
5061 | update_rq_clock(rq); | |
5062 | ||
5063 | if (p->state == TASK_UNINTERRUPTIBLE) | |
5064 | rq->nr_uninterruptible--; | |
5065 | ||
5066 | enqueue_task(rq, p, 0); | |
5067 | inc_nr_running(p, rq); | |
5068 | } | |
5069 | ||
dd41f596 IM |
5070 | /* |
5071 | * Schedules idle task to be the next runnable task on current CPU. | |
1da177e4 | 5072 | * It does so by boosting its priority to highest possible and adding it to |
48f24c4d | 5073 | * the _front_ of the runqueue. Used by CPU offline code. |
1da177e4 LT |
5074 | */ |
5075 | void sched_idle_next(void) | |
5076 | { | |
48f24c4d | 5077 | int this_cpu = smp_processor_id(); |
70b97a7f | 5078 | struct rq *rq = cpu_rq(this_cpu); |
1da177e4 LT |
5079 | struct task_struct *p = rq->idle; |
5080 | unsigned long flags; | |
5081 | ||
5082 | /* cpu has to be offline */ | |
48f24c4d | 5083 | BUG_ON(cpu_online(this_cpu)); |
1da177e4 | 5084 | |
48f24c4d IM |
5085 | /* |
5086 | * Strictly not necessary since rest of the CPUs are stopped by now | |
5087 | * and interrupts disabled on the current cpu. | |
1da177e4 LT |
5088 | */ |
5089 | spin_lock_irqsave(&rq->lock, flags); | |
5090 | ||
dd41f596 | 5091 | __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1); |
48f24c4d IM |
5092 | |
5093 | /* Add idle task to the _front_ of its priority queue: */ | |
dd41f596 | 5094 | activate_idle_task(p, rq); |
1da177e4 LT |
5095 | |
5096 | spin_unlock_irqrestore(&rq->lock, flags); | |
5097 | } | |
5098 | ||
48f24c4d IM |
5099 | /* |
5100 | * Ensures that the idle task is using init_mm right before its cpu goes | |
1da177e4 LT |
5101 | * offline. |
5102 | */ | |
5103 | void idle_task_exit(void) | |
5104 | { | |
5105 | struct mm_struct *mm = current->active_mm; | |
5106 | ||
5107 | BUG_ON(cpu_online(smp_processor_id())); | |
5108 | ||
5109 | if (mm != &init_mm) | |
5110 | switch_mm(mm, &init_mm, current); | |
5111 | mmdrop(mm); | |
5112 | } | |
5113 | ||
054b9108 | 5114 | /* called under rq->lock with disabled interrupts */ |
36c8b586 | 5115 | static void migrate_dead(unsigned int dead_cpu, struct task_struct *p) |
1da177e4 | 5116 | { |
70b97a7f | 5117 | struct rq *rq = cpu_rq(dead_cpu); |
1da177e4 LT |
5118 | |
5119 | /* Must be exiting, otherwise would be on tasklist. */ | |
48f24c4d | 5120 | BUG_ON(p->exit_state != EXIT_ZOMBIE && p->exit_state != EXIT_DEAD); |
1da177e4 LT |
5121 | |
5122 | /* Cannot have done final schedule yet: would have vanished. */ | |
c394cc9f | 5123 | BUG_ON(p->state == TASK_DEAD); |
1da177e4 | 5124 | |
48f24c4d | 5125 | get_task_struct(p); |
1da177e4 LT |
5126 | |
5127 | /* | |
5128 | * Drop lock around migration; if someone else moves it, | |
5129 | * that's OK. No task can be added to this CPU, so iteration is | |
5130 | * fine. | |
054b9108 | 5131 | * NOTE: interrupts should be left disabled --dev@ |
1da177e4 | 5132 | */ |
054b9108 | 5133 | spin_unlock(&rq->lock); |
48f24c4d | 5134 | move_task_off_dead_cpu(dead_cpu, p); |
054b9108 | 5135 | spin_lock(&rq->lock); |
1da177e4 | 5136 | |
48f24c4d | 5137 | put_task_struct(p); |
1da177e4 LT |
5138 | } |
5139 | ||
5140 | /* release_task() removes task from tasklist, so we won't find dead tasks. */ | |
5141 | static void migrate_dead_tasks(unsigned int dead_cpu) | |
5142 | { | |
70b97a7f | 5143 | struct rq *rq = cpu_rq(dead_cpu); |
dd41f596 | 5144 | struct task_struct *next; |
48f24c4d | 5145 | |
dd41f596 IM |
5146 | for ( ; ; ) { |
5147 | if (!rq->nr_running) | |
5148 | break; | |
a8e504d2 | 5149 | update_rq_clock(rq); |
ff95f3df | 5150 | next = pick_next_task(rq, rq->curr); |
dd41f596 IM |
5151 | if (!next) |
5152 | break; | |
5153 | migrate_dead(dead_cpu, next); | |
e692ab53 | 5154 | |
1da177e4 LT |
5155 | } |
5156 | } | |
5157 | #endif /* CONFIG_HOTPLUG_CPU */ | |
5158 | ||
e692ab53 NP |
5159 | #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL) |
5160 | ||
5161 | static struct ctl_table sd_ctl_dir[] = { | |
e0361851 AD |
5162 | { |
5163 | .procname = "sched_domain", | |
c57baf1e | 5164 | .mode = 0555, |
e0361851 | 5165 | }, |
e692ab53 NP |
5166 | {0,}, |
5167 | }; | |
5168 | ||
5169 | static struct ctl_table sd_ctl_root[] = { | |
e0361851 | 5170 | { |
c57baf1e | 5171 | .ctl_name = CTL_KERN, |
e0361851 | 5172 | .procname = "kernel", |
c57baf1e | 5173 | .mode = 0555, |
e0361851 AD |
5174 | .child = sd_ctl_dir, |
5175 | }, | |
e692ab53 NP |
5176 | {0,}, |
5177 | }; | |
5178 | ||
5179 | static struct ctl_table *sd_alloc_ctl_entry(int n) | |
5180 | { | |
5181 | struct ctl_table *entry = | |
5182 | kmalloc(n * sizeof(struct ctl_table), GFP_KERNEL); | |
5183 | ||
5184 | BUG_ON(!entry); | |
5185 | memset(entry, 0, n * sizeof(struct ctl_table)); | |
5186 | ||
5187 | return entry; | |
5188 | } | |
5189 | ||
5190 | static void | |
e0361851 | 5191 | set_table_entry(struct ctl_table *entry, |
e692ab53 NP |
5192 | const char *procname, void *data, int maxlen, |
5193 | mode_t mode, proc_handler *proc_handler) | |
5194 | { | |
e692ab53 NP |
5195 | entry->procname = procname; |
5196 | entry->data = data; | |
5197 | entry->maxlen = maxlen; | |
5198 | entry->mode = mode; | |
5199 | entry->proc_handler = proc_handler; | |
5200 | } | |
5201 | ||
5202 | static struct ctl_table * | |
5203 | sd_alloc_ctl_domain_table(struct sched_domain *sd) | |
5204 | { | |
ace8b3d6 | 5205 | struct ctl_table *table = sd_alloc_ctl_entry(12); |
e692ab53 | 5206 | |
e0361851 | 5207 | set_table_entry(&table[0], "min_interval", &sd->min_interval, |
e692ab53 | 5208 | sizeof(long), 0644, proc_doulongvec_minmax); |
e0361851 | 5209 | set_table_entry(&table[1], "max_interval", &sd->max_interval, |
e692ab53 | 5210 | sizeof(long), 0644, proc_doulongvec_minmax); |
e0361851 | 5211 | set_table_entry(&table[2], "busy_idx", &sd->busy_idx, |
e692ab53 | 5212 | sizeof(int), 0644, proc_dointvec_minmax); |
e0361851 | 5213 | set_table_entry(&table[3], "idle_idx", &sd->idle_idx, |
e692ab53 | 5214 | sizeof(int), 0644, proc_dointvec_minmax); |
e0361851 | 5215 | set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx, |
e692ab53 | 5216 | sizeof(int), 0644, proc_dointvec_minmax); |
e0361851 | 5217 | set_table_entry(&table[5], "wake_idx", &sd->wake_idx, |
e692ab53 | 5218 | sizeof(int), 0644, proc_dointvec_minmax); |
e0361851 | 5219 | set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx, |
e692ab53 | 5220 | sizeof(int), 0644, proc_dointvec_minmax); |
e0361851 | 5221 | set_table_entry(&table[7], "busy_factor", &sd->busy_factor, |
e692ab53 | 5222 | sizeof(int), 0644, proc_dointvec_minmax); |
e0361851 | 5223 | set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct, |
e692ab53 | 5224 | sizeof(int), 0644, proc_dointvec_minmax); |
ace8b3d6 | 5225 | set_table_entry(&table[9], "cache_nice_tries", |
e692ab53 NP |
5226 | &sd->cache_nice_tries, |
5227 | sizeof(int), 0644, proc_dointvec_minmax); | |
ace8b3d6 | 5228 | set_table_entry(&table[10], "flags", &sd->flags, |
e692ab53 NP |
5229 | sizeof(int), 0644, proc_dointvec_minmax); |
5230 | ||
5231 | return table; | |
5232 | } | |
5233 | ||
5234 | static ctl_table *sd_alloc_ctl_cpu_table(int cpu) | |
5235 | { | |
5236 | struct ctl_table *entry, *table; | |
5237 | struct sched_domain *sd; | |
5238 | int domain_num = 0, i; | |
5239 | char buf[32]; | |
5240 | ||
5241 | for_each_domain(cpu, sd) | |
5242 | domain_num++; | |
5243 | entry = table = sd_alloc_ctl_entry(domain_num + 1); | |
5244 | ||
5245 | i = 0; | |
5246 | for_each_domain(cpu, sd) { | |
5247 | snprintf(buf, 32, "domain%d", i); | |
e692ab53 | 5248 | entry->procname = kstrdup(buf, GFP_KERNEL); |
c57baf1e | 5249 | entry->mode = 0555; |
e692ab53 NP |
5250 | entry->child = sd_alloc_ctl_domain_table(sd); |
5251 | entry++; | |
5252 | i++; | |
5253 | } | |
5254 | return table; | |
5255 | } | |
5256 | ||
5257 | static struct ctl_table_header *sd_sysctl_header; | |
5258 | static void init_sched_domain_sysctl(void) | |
5259 | { | |
5260 | int i, cpu_num = num_online_cpus(); | |
5261 | struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1); | |
5262 | char buf[32]; | |
5263 | ||
5264 | sd_ctl_dir[0].child = entry; | |
5265 | ||
5266 | for (i = 0; i < cpu_num; i++, entry++) { | |
5267 | snprintf(buf, 32, "cpu%d", i); | |
e692ab53 | 5268 | entry->procname = kstrdup(buf, GFP_KERNEL); |
c57baf1e | 5269 | entry->mode = 0555; |
e692ab53 NP |
5270 | entry->child = sd_alloc_ctl_cpu_table(i); |
5271 | } | |
5272 | sd_sysctl_header = register_sysctl_table(sd_ctl_root); | |
5273 | } | |
5274 | #else | |
5275 | static void init_sched_domain_sysctl(void) | |
5276 | { | |
5277 | } | |
5278 | #endif | |
5279 | ||
1da177e4 LT |
5280 | /* |
5281 | * migration_call - callback that gets triggered when a CPU is added. | |
5282 | * Here we can start up the necessary migration thread for the new CPU. | |
5283 | */ | |
48f24c4d IM |
5284 | static int __cpuinit |
5285 | migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) | |
1da177e4 | 5286 | { |
1da177e4 | 5287 | struct task_struct *p; |
48f24c4d | 5288 | int cpu = (long)hcpu; |
1da177e4 | 5289 | unsigned long flags; |
70b97a7f | 5290 | struct rq *rq; |
1da177e4 LT |
5291 | |
5292 | switch (action) { | |
5be9361c GS |
5293 | case CPU_LOCK_ACQUIRE: |
5294 | mutex_lock(&sched_hotcpu_mutex); | |
5295 | break; | |
5296 | ||
1da177e4 | 5297 | case CPU_UP_PREPARE: |
8bb78442 | 5298 | case CPU_UP_PREPARE_FROZEN: |
dd41f596 | 5299 | p = kthread_create(migration_thread, hcpu, "migration/%d", cpu); |
1da177e4 LT |
5300 | if (IS_ERR(p)) |
5301 | return NOTIFY_BAD; | |
1da177e4 LT |
5302 | kthread_bind(p, cpu); |
5303 | /* Must be high prio: stop_machine expects to yield to it. */ | |
5304 | rq = task_rq_lock(p, &flags); | |
dd41f596 | 5305 | __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1); |
1da177e4 LT |
5306 | task_rq_unlock(rq, &flags); |
5307 | cpu_rq(cpu)->migration_thread = p; | |
5308 | break; | |
48f24c4d | 5309 | |
1da177e4 | 5310 | case CPU_ONLINE: |
8bb78442 | 5311 | case CPU_ONLINE_FROZEN: |
1da177e4 LT |
5312 | /* Strictly unneccessary, as first user will wake it. */ |
5313 | wake_up_process(cpu_rq(cpu)->migration_thread); | |
5314 | break; | |
48f24c4d | 5315 | |
1da177e4 LT |
5316 | #ifdef CONFIG_HOTPLUG_CPU |
5317 | case CPU_UP_CANCELED: | |
8bb78442 | 5318 | case CPU_UP_CANCELED_FROZEN: |
fc75cdfa HC |
5319 | if (!cpu_rq(cpu)->migration_thread) |
5320 | break; | |
1da177e4 | 5321 | /* Unbind it from offline cpu so it can run. Fall thru. */ |
a4c4af7c HC |
5322 | kthread_bind(cpu_rq(cpu)->migration_thread, |
5323 | any_online_cpu(cpu_online_map)); | |
1da177e4 LT |
5324 | kthread_stop(cpu_rq(cpu)->migration_thread); |
5325 | cpu_rq(cpu)->migration_thread = NULL; | |
5326 | break; | |
48f24c4d | 5327 | |
1da177e4 | 5328 | case CPU_DEAD: |
8bb78442 | 5329 | case CPU_DEAD_FROZEN: |
1da177e4 LT |
5330 | migrate_live_tasks(cpu); |
5331 | rq = cpu_rq(cpu); | |
5332 | kthread_stop(rq->migration_thread); | |
5333 | rq->migration_thread = NULL; | |
5334 | /* Idle task back to normal (off runqueue, low prio) */ | |
5335 | rq = task_rq_lock(rq->idle, &flags); | |
a8e504d2 | 5336 | update_rq_clock(rq); |
2e1cb74a | 5337 | deactivate_task(rq, rq->idle, 0); |
1da177e4 | 5338 | rq->idle->static_prio = MAX_PRIO; |
dd41f596 IM |
5339 | __setscheduler(rq, rq->idle, SCHED_NORMAL, 0); |
5340 | rq->idle->sched_class = &idle_sched_class; | |
1da177e4 LT |
5341 | migrate_dead_tasks(cpu); |
5342 | task_rq_unlock(rq, &flags); | |
5343 | migrate_nr_uninterruptible(rq); | |
5344 | BUG_ON(rq->nr_running != 0); | |
5345 | ||
5346 | /* No need to migrate the tasks: it was best-effort if | |
5be9361c | 5347 | * they didn't take sched_hotcpu_mutex. Just wake up |
1da177e4 LT |
5348 | * the requestors. */ |
5349 | spin_lock_irq(&rq->lock); | |
5350 | while (!list_empty(&rq->migration_queue)) { | |
70b97a7f IM |
5351 | struct migration_req *req; |
5352 | ||
1da177e4 | 5353 | req = list_entry(rq->migration_queue.next, |
70b97a7f | 5354 | struct migration_req, list); |
1da177e4 LT |
5355 | list_del_init(&req->list); |
5356 | complete(&req->done); | |
5357 | } | |
5358 | spin_unlock_irq(&rq->lock); | |
5359 | break; | |
5360 | #endif | |
5be9361c GS |
5361 | case CPU_LOCK_RELEASE: |
5362 | mutex_unlock(&sched_hotcpu_mutex); | |
5363 | break; | |
1da177e4 LT |
5364 | } |
5365 | return NOTIFY_OK; | |
5366 | } | |
5367 | ||
5368 | /* Register at highest priority so that task migration (migrate_all_tasks) | |
5369 | * happens before everything else. | |
5370 | */ | |
26c2143b | 5371 | static struct notifier_block __cpuinitdata migration_notifier = { |
1da177e4 LT |
5372 | .notifier_call = migration_call, |
5373 | .priority = 10 | |
5374 | }; | |
5375 | ||
5376 | int __init migration_init(void) | |
5377 | { | |
5378 | void *cpu = (void *)(long)smp_processor_id(); | |
07dccf33 | 5379 | int err; |
48f24c4d IM |
5380 | |
5381 | /* Start one for the boot CPU: */ | |
07dccf33 AM |
5382 | err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu); |
5383 | BUG_ON(err == NOTIFY_BAD); | |
1da177e4 LT |
5384 | migration_call(&migration_notifier, CPU_ONLINE, cpu); |
5385 | register_cpu_notifier(&migration_notifier); | |
48f24c4d | 5386 | |
1da177e4 LT |
5387 | return 0; |
5388 | } | |
5389 | #endif | |
5390 | ||
5391 | #ifdef CONFIG_SMP | |
476f3534 CL |
5392 | |
5393 | /* Number of possible processor ids */ | |
5394 | int nr_cpu_ids __read_mostly = NR_CPUS; | |
5395 | EXPORT_SYMBOL(nr_cpu_ids); | |
5396 | ||
3e9830dc | 5397 | #ifdef CONFIG_SCHED_DEBUG |
1da177e4 LT |
5398 | static void sched_domain_debug(struct sched_domain *sd, int cpu) |
5399 | { | |
5400 | int level = 0; | |
5401 | ||
41c7ce9a NP |
5402 | if (!sd) { |
5403 | printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu); | |
5404 | return; | |
5405 | } | |
5406 | ||
1da177e4 LT |
5407 | printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu); |
5408 | ||
5409 | do { | |
5410 | int i; | |
5411 | char str[NR_CPUS]; | |
5412 | struct sched_group *group = sd->groups; | |
5413 | cpumask_t groupmask; | |
5414 | ||
5415 | cpumask_scnprintf(str, NR_CPUS, sd->span); | |
5416 | cpus_clear(groupmask); | |
5417 | ||
5418 | printk(KERN_DEBUG); | |
5419 | for (i = 0; i < level + 1; i++) | |
5420 | printk(" "); | |
5421 | printk("domain %d: ", level); | |
5422 | ||
5423 | if (!(sd->flags & SD_LOAD_BALANCE)) { | |
5424 | printk("does not load-balance\n"); | |
5425 | if (sd->parent) | |
33859f7f MOS |
5426 | printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain" |
5427 | " has parent"); | |
1da177e4 LT |
5428 | break; |
5429 | } | |
5430 | ||
5431 | printk("span %s\n", str); | |
5432 | ||
5433 | if (!cpu_isset(cpu, sd->span)) | |
33859f7f MOS |
5434 | printk(KERN_ERR "ERROR: domain->span does not contain " |
5435 | "CPU%d\n", cpu); | |
1da177e4 | 5436 | if (!cpu_isset(cpu, group->cpumask)) |
33859f7f MOS |
5437 | printk(KERN_ERR "ERROR: domain->groups does not contain" |
5438 | " CPU%d\n", cpu); | |
1da177e4 LT |
5439 | |
5440 | printk(KERN_DEBUG); | |
5441 | for (i = 0; i < level + 2; i++) | |
5442 | printk(" "); | |
5443 | printk("groups:"); | |
5444 | do { | |
5445 | if (!group) { | |
5446 | printk("\n"); | |
5447 | printk(KERN_ERR "ERROR: group is NULL\n"); | |
5448 | break; | |
5449 | } | |
5450 | ||
5517d86b | 5451 | if (!group->__cpu_power) { |
1da177e4 | 5452 | printk("\n"); |
33859f7f MOS |
5453 | printk(KERN_ERR "ERROR: domain->cpu_power not " |
5454 | "set\n"); | |
26797a34 | 5455 | break; |
1da177e4 LT |
5456 | } |
5457 | ||
5458 | if (!cpus_weight(group->cpumask)) { | |
5459 | printk("\n"); | |
5460 | printk(KERN_ERR "ERROR: empty group\n"); | |
26797a34 | 5461 | break; |
1da177e4 LT |
5462 | } |
5463 | ||
5464 | if (cpus_intersects(groupmask, group->cpumask)) { | |
5465 | printk("\n"); | |
5466 | printk(KERN_ERR "ERROR: repeated CPUs\n"); | |
26797a34 | 5467 | break; |
1da177e4 LT |
5468 | } |
5469 | ||
5470 | cpus_or(groupmask, groupmask, group->cpumask); | |
5471 | ||
5472 | cpumask_scnprintf(str, NR_CPUS, group->cpumask); | |
5473 | printk(" %s", str); | |
5474 | ||
5475 | group = group->next; | |
5476 | } while (group != sd->groups); | |
5477 | printk("\n"); | |
5478 | ||
5479 | if (!cpus_equal(sd->span, groupmask)) | |
33859f7f MOS |
5480 | printk(KERN_ERR "ERROR: groups don't span " |
5481 | "domain->span\n"); | |
1da177e4 LT |
5482 | |
5483 | level++; | |
5484 | sd = sd->parent; | |
33859f7f MOS |
5485 | if (!sd) |
5486 | continue; | |
1da177e4 | 5487 | |
33859f7f MOS |
5488 | if (!cpus_subset(groupmask, sd->span)) |
5489 | printk(KERN_ERR "ERROR: parent span is not a superset " | |
5490 | "of domain->span\n"); | |
1da177e4 LT |
5491 | |
5492 | } while (sd); | |
5493 | } | |
5494 | #else | |
48f24c4d | 5495 | # define sched_domain_debug(sd, cpu) do { } while (0) |
1da177e4 LT |
5496 | #endif |
5497 | ||
1a20ff27 | 5498 | static int sd_degenerate(struct sched_domain *sd) |
245af2c7 SS |
5499 | { |
5500 | if (cpus_weight(sd->span) == 1) | |
5501 | return 1; | |
5502 | ||
5503 | /* Following flags need at least 2 groups */ | |
5504 | if (sd->flags & (SD_LOAD_BALANCE | | |
5505 | SD_BALANCE_NEWIDLE | | |
5506 | SD_BALANCE_FORK | | |
89c4710e SS |
5507 | SD_BALANCE_EXEC | |
5508 | SD_SHARE_CPUPOWER | | |
5509 | SD_SHARE_PKG_RESOURCES)) { | |
245af2c7 SS |
5510 | if (sd->groups != sd->groups->next) |
5511 | return 0; | |
5512 | } | |
5513 | ||
5514 | /* Following flags don't use groups */ | |
5515 | if (sd->flags & (SD_WAKE_IDLE | | |
5516 | SD_WAKE_AFFINE | | |
5517 | SD_WAKE_BALANCE)) | |
5518 | return 0; | |
5519 | ||
5520 | return 1; | |
5521 | } | |
5522 | ||
48f24c4d IM |
5523 | static int |
5524 | sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent) | |
245af2c7 SS |
5525 | { |
5526 | unsigned long cflags = sd->flags, pflags = parent->flags; | |
5527 | ||
5528 | if (sd_degenerate(parent)) | |
5529 | return 1; | |
5530 | ||
5531 | if (!cpus_equal(sd->span, parent->span)) | |
5532 | return 0; | |
5533 | ||
5534 | /* Does parent contain flags not in child? */ | |
5535 | /* WAKE_BALANCE is a subset of WAKE_AFFINE */ | |
5536 | if (cflags & SD_WAKE_AFFINE) | |
5537 | pflags &= ~SD_WAKE_BALANCE; | |
5538 | /* Flags needing groups don't count if only 1 group in parent */ | |
5539 | if (parent->groups == parent->groups->next) { | |
5540 | pflags &= ~(SD_LOAD_BALANCE | | |
5541 | SD_BALANCE_NEWIDLE | | |
5542 | SD_BALANCE_FORK | | |
89c4710e SS |
5543 | SD_BALANCE_EXEC | |
5544 | SD_SHARE_CPUPOWER | | |
5545 | SD_SHARE_PKG_RESOURCES); | |
245af2c7 SS |
5546 | } |
5547 | if (~cflags & pflags) | |
5548 | return 0; | |
5549 | ||
5550 | return 1; | |
5551 | } | |
5552 | ||
1da177e4 LT |
5553 | /* |
5554 | * Attach the domain 'sd' to 'cpu' as its base domain. Callers must | |
5555 | * hold the hotplug lock. | |
5556 | */ | |
9c1cfda2 | 5557 | static void cpu_attach_domain(struct sched_domain *sd, int cpu) |
1da177e4 | 5558 | { |
70b97a7f | 5559 | struct rq *rq = cpu_rq(cpu); |
245af2c7 SS |
5560 | struct sched_domain *tmp; |
5561 | ||
5562 | /* Remove the sched domains which do not contribute to scheduling. */ | |
5563 | for (tmp = sd; tmp; tmp = tmp->parent) { | |
5564 | struct sched_domain *parent = tmp->parent; | |
5565 | if (!parent) | |
5566 | break; | |
1a848870 | 5567 | if (sd_parent_degenerate(tmp, parent)) { |
245af2c7 | 5568 | tmp->parent = parent->parent; |
1a848870 SS |
5569 | if (parent->parent) |
5570 | parent->parent->child = tmp; | |
5571 | } | |
245af2c7 SS |
5572 | } |
5573 | ||
1a848870 | 5574 | if (sd && sd_degenerate(sd)) { |
245af2c7 | 5575 | sd = sd->parent; |
1a848870 SS |
5576 | if (sd) |
5577 | sd->child = NULL; | |
5578 | } | |
1da177e4 LT |
5579 | |
5580 | sched_domain_debug(sd, cpu); | |
5581 | ||
674311d5 | 5582 | rcu_assign_pointer(rq->sd, sd); |
1da177e4 LT |
5583 | } |
5584 | ||
5585 | /* cpus with isolated domains */ | |
67af63a6 | 5586 | static cpumask_t cpu_isolated_map = CPU_MASK_NONE; |
1da177e4 LT |
5587 | |
5588 | /* Setup the mask of cpus configured for isolated domains */ | |
5589 | static int __init isolated_cpu_setup(char *str) | |
5590 | { | |
5591 | int ints[NR_CPUS], i; | |
5592 | ||
5593 | str = get_options(str, ARRAY_SIZE(ints), ints); | |
5594 | cpus_clear(cpu_isolated_map); | |
5595 | for (i = 1; i <= ints[0]; i++) | |
5596 | if (ints[i] < NR_CPUS) | |
5597 | cpu_set(ints[i], cpu_isolated_map); | |
5598 | return 1; | |
5599 | } | |
5600 | ||
8927f494 | 5601 | __setup("isolcpus=", isolated_cpu_setup); |
1da177e4 LT |
5602 | |
5603 | /* | |
6711cab4 SS |
5604 | * init_sched_build_groups takes the cpumask we wish to span, and a pointer |
5605 | * to a function which identifies what group(along with sched group) a CPU | |
5606 | * belongs to. The return value of group_fn must be a >= 0 and < NR_CPUS | |
5607 | * (due to the fact that we keep track of groups covered with a cpumask_t). | |
1da177e4 LT |
5608 | * |
5609 | * init_sched_build_groups will build a circular linked list of the groups | |
5610 | * covered by the given span, and will set each group's ->cpumask correctly, | |
5611 | * and ->cpu_power to 0. | |
5612 | */ | |
a616058b | 5613 | static void |
6711cab4 SS |
5614 | init_sched_build_groups(cpumask_t span, const cpumask_t *cpu_map, |
5615 | int (*group_fn)(int cpu, const cpumask_t *cpu_map, | |
5616 | struct sched_group **sg)) | |
1da177e4 LT |
5617 | { |
5618 | struct sched_group *first = NULL, *last = NULL; | |
5619 | cpumask_t covered = CPU_MASK_NONE; | |
5620 | int i; | |
5621 | ||
5622 | for_each_cpu_mask(i, span) { | |
6711cab4 SS |
5623 | struct sched_group *sg; |
5624 | int group = group_fn(i, cpu_map, &sg); | |
1da177e4 LT |
5625 | int j; |
5626 | ||
5627 | if (cpu_isset(i, covered)) | |
5628 | continue; | |
5629 | ||
5630 | sg->cpumask = CPU_MASK_NONE; | |
5517d86b | 5631 | sg->__cpu_power = 0; |
1da177e4 LT |
5632 | |
5633 | for_each_cpu_mask(j, span) { | |
6711cab4 | 5634 | if (group_fn(j, cpu_map, NULL) != group) |
1da177e4 LT |
5635 | continue; |
5636 | ||
5637 | cpu_set(j, covered); | |
5638 | cpu_set(j, sg->cpumask); | |
5639 | } | |
5640 | if (!first) | |
5641 | first = sg; | |
5642 | if (last) | |
5643 | last->next = sg; | |
5644 | last = sg; | |
5645 | } | |
5646 | last->next = first; | |
5647 | } | |
5648 | ||
9c1cfda2 | 5649 | #define SD_NODES_PER_DOMAIN 16 |
1da177e4 | 5650 | |
9c1cfda2 | 5651 | #ifdef CONFIG_NUMA |
198e2f18 | 5652 | |
9c1cfda2 JH |
5653 | /** |
5654 | * find_next_best_node - find the next node to include in a sched_domain | |
5655 | * @node: node whose sched_domain we're building | |
5656 | * @used_nodes: nodes already in the sched_domain | |
5657 | * | |
5658 | * Find the next node to include in a given scheduling domain. Simply | |
5659 | * finds the closest node not already in the @used_nodes map. | |
5660 | * | |
5661 | * Should use nodemask_t. | |
5662 | */ | |
5663 | static int find_next_best_node(int node, unsigned long *used_nodes) | |
5664 | { | |
5665 | int i, n, val, min_val, best_node = 0; | |
5666 | ||
5667 | min_val = INT_MAX; | |
5668 | ||
5669 | for (i = 0; i < MAX_NUMNODES; i++) { | |
5670 | /* Start at @node */ | |
5671 | n = (node + i) % MAX_NUMNODES; | |
5672 | ||
5673 | if (!nr_cpus_node(n)) | |
5674 | continue; | |
5675 | ||
5676 | /* Skip already used nodes */ | |
5677 | if (test_bit(n, used_nodes)) | |
5678 | continue; | |
5679 | ||
5680 | /* Simple min distance search */ | |
5681 | val = node_distance(node, n); | |
5682 | ||
5683 | if (val < min_val) { | |
5684 | min_val = val; | |
5685 | best_node = n; | |
5686 | } | |
5687 | } | |
5688 | ||
5689 | set_bit(best_node, used_nodes); | |
5690 | return best_node; | |
5691 | } | |
5692 | ||
5693 | /** | |
5694 | * sched_domain_node_span - get a cpumask for a node's sched_domain | |
5695 | * @node: node whose cpumask we're constructing | |
5696 | * @size: number of nodes to include in this span | |
5697 | * | |
5698 | * Given a node, construct a good cpumask for its sched_domain to span. It | |
5699 | * should be one that prevents unnecessary balancing, but also spreads tasks | |
5700 | * out optimally. | |
5701 | */ | |
5702 | static cpumask_t sched_domain_node_span(int node) | |
5703 | { | |
9c1cfda2 | 5704 | DECLARE_BITMAP(used_nodes, MAX_NUMNODES); |
48f24c4d IM |
5705 | cpumask_t span, nodemask; |
5706 | int i; | |
9c1cfda2 JH |
5707 | |
5708 | cpus_clear(span); | |
5709 | bitmap_zero(used_nodes, MAX_NUMNODES); | |
5710 | ||
5711 | nodemask = node_to_cpumask(node); | |
5712 | cpus_or(span, span, nodemask); | |
5713 | set_bit(node, used_nodes); | |
5714 | ||
5715 | for (i = 1; i < SD_NODES_PER_DOMAIN; i++) { | |
5716 | int next_node = find_next_best_node(node, used_nodes); | |
48f24c4d | 5717 | |
9c1cfda2 JH |
5718 | nodemask = node_to_cpumask(next_node); |
5719 | cpus_or(span, span, nodemask); | |
5720 | } | |
5721 | ||
5722 | return span; | |
5723 | } | |
5724 | #endif | |
5725 | ||
5c45bf27 | 5726 | int sched_smt_power_savings = 0, sched_mc_power_savings = 0; |
48f24c4d | 5727 | |
9c1cfda2 | 5728 | /* |
48f24c4d | 5729 | * SMT sched-domains: |
9c1cfda2 | 5730 | */ |
1da177e4 LT |
5731 | #ifdef CONFIG_SCHED_SMT |
5732 | static DEFINE_PER_CPU(struct sched_domain, cpu_domains); | |
6711cab4 | 5733 | static DEFINE_PER_CPU(struct sched_group, sched_group_cpus); |
48f24c4d | 5734 | |
6711cab4 SS |
5735 | static int cpu_to_cpu_group(int cpu, const cpumask_t *cpu_map, |
5736 | struct sched_group **sg) | |
1da177e4 | 5737 | { |
6711cab4 SS |
5738 | if (sg) |
5739 | *sg = &per_cpu(sched_group_cpus, cpu); | |
1da177e4 LT |
5740 | return cpu; |
5741 | } | |
5742 | #endif | |
5743 | ||
48f24c4d IM |
5744 | /* |
5745 | * multi-core sched-domains: | |
5746 | */ | |
1e9f28fa SS |
5747 | #ifdef CONFIG_SCHED_MC |
5748 | static DEFINE_PER_CPU(struct sched_domain, core_domains); | |
6711cab4 | 5749 | static DEFINE_PER_CPU(struct sched_group, sched_group_core); |
1e9f28fa SS |
5750 | #endif |
5751 | ||
5752 | #if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT) | |
6711cab4 SS |
5753 | static int cpu_to_core_group(int cpu, const cpumask_t *cpu_map, |
5754 | struct sched_group **sg) | |
1e9f28fa | 5755 | { |
6711cab4 | 5756 | int group; |
a616058b SS |
5757 | cpumask_t mask = cpu_sibling_map[cpu]; |
5758 | cpus_and(mask, mask, *cpu_map); | |
6711cab4 SS |
5759 | group = first_cpu(mask); |
5760 | if (sg) | |
5761 | *sg = &per_cpu(sched_group_core, group); | |
5762 | return group; | |
1e9f28fa SS |
5763 | } |
5764 | #elif defined(CONFIG_SCHED_MC) | |
6711cab4 SS |
5765 | static int cpu_to_core_group(int cpu, const cpumask_t *cpu_map, |
5766 | struct sched_group **sg) | |
1e9f28fa | 5767 | { |
6711cab4 SS |
5768 | if (sg) |
5769 | *sg = &per_cpu(sched_group_core, cpu); | |
1e9f28fa SS |
5770 | return cpu; |
5771 | } | |
5772 | #endif | |
5773 | ||
1da177e4 | 5774 | static DEFINE_PER_CPU(struct sched_domain, phys_domains); |
6711cab4 | 5775 | static DEFINE_PER_CPU(struct sched_group, sched_group_phys); |
48f24c4d | 5776 | |
6711cab4 SS |
5777 | static int cpu_to_phys_group(int cpu, const cpumask_t *cpu_map, |
5778 | struct sched_group **sg) | |
1da177e4 | 5779 | { |
6711cab4 | 5780 | int group; |
48f24c4d | 5781 | #ifdef CONFIG_SCHED_MC |
1e9f28fa | 5782 | cpumask_t mask = cpu_coregroup_map(cpu); |
a616058b | 5783 | cpus_and(mask, mask, *cpu_map); |
6711cab4 | 5784 | group = first_cpu(mask); |
1e9f28fa | 5785 | #elif defined(CONFIG_SCHED_SMT) |
a616058b SS |
5786 | cpumask_t mask = cpu_sibling_map[cpu]; |
5787 | cpus_and(mask, mask, *cpu_map); | |
6711cab4 | 5788 | group = first_cpu(mask); |
1da177e4 | 5789 | #else |
6711cab4 | 5790 | group = cpu; |
1da177e4 | 5791 | #endif |
6711cab4 SS |
5792 | if (sg) |
5793 | *sg = &per_cpu(sched_group_phys, group); | |
5794 | return group; | |
1da177e4 LT |
5795 | } |
5796 | ||
5797 | #ifdef CONFIG_NUMA | |
1da177e4 | 5798 | /* |
9c1cfda2 JH |
5799 | * The init_sched_build_groups can't handle what we want to do with node |
5800 | * groups, so roll our own. Now each node has its own list of groups which | |
5801 | * gets dynamically allocated. | |
1da177e4 | 5802 | */ |
9c1cfda2 | 5803 | static DEFINE_PER_CPU(struct sched_domain, node_domains); |
d1b55138 | 5804 | static struct sched_group **sched_group_nodes_bycpu[NR_CPUS]; |
1da177e4 | 5805 | |
9c1cfda2 | 5806 | static DEFINE_PER_CPU(struct sched_domain, allnodes_domains); |
6711cab4 | 5807 | static DEFINE_PER_CPU(struct sched_group, sched_group_allnodes); |
9c1cfda2 | 5808 | |
6711cab4 SS |
5809 | static int cpu_to_allnodes_group(int cpu, const cpumask_t *cpu_map, |
5810 | struct sched_group **sg) | |
9c1cfda2 | 5811 | { |
6711cab4 SS |
5812 | cpumask_t nodemask = node_to_cpumask(cpu_to_node(cpu)); |
5813 | int group; | |
5814 | ||
5815 | cpus_and(nodemask, nodemask, *cpu_map); | |
5816 | group = first_cpu(nodemask); | |
5817 | ||
5818 | if (sg) | |
5819 | *sg = &per_cpu(sched_group_allnodes, group); | |
5820 | return group; | |
1da177e4 | 5821 | } |
6711cab4 | 5822 | |
08069033 SS |
5823 | static void init_numa_sched_groups_power(struct sched_group *group_head) |
5824 | { | |
5825 | struct sched_group *sg = group_head; | |
5826 | int j; | |
5827 | ||
5828 | if (!sg) | |
5829 | return; | |
3a5c359a AK |
5830 | do { |
5831 | for_each_cpu_mask(j, sg->cpumask) { | |
5832 | struct sched_domain *sd; | |
08069033 | 5833 | |
3a5c359a AK |
5834 | sd = &per_cpu(phys_domains, j); |
5835 | if (j != first_cpu(sd->groups->cpumask)) { | |
5836 | /* | |
5837 | * Only add "power" once for each | |
5838 | * physical package. | |
5839 | */ | |
5840 | continue; | |
5841 | } | |
08069033 | 5842 | |
3a5c359a AK |
5843 | sg_inc_cpu_power(sg, sd->groups->__cpu_power); |
5844 | } | |
5845 | sg = sg->next; | |
5846 | } while (sg != group_head); | |
08069033 | 5847 | } |
1da177e4 LT |
5848 | #endif |
5849 | ||
a616058b | 5850 | #ifdef CONFIG_NUMA |
51888ca2 SV |
5851 | /* Free memory allocated for various sched_group structures */ |
5852 | static void free_sched_groups(const cpumask_t *cpu_map) | |
5853 | { | |
a616058b | 5854 | int cpu, i; |
51888ca2 SV |
5855 | |
5856 | for_each_cpu_mask(cpu, *cpu_map) { | |
51888ca2 SV |
5857 | struct sched_group **sched_group_nodes |
5858 | = sched_group_nodes_bycpu[cpu]; | |
5859 | ||
51888ca2 SV |
5860 | if (!sched_group_nodes) |
5861 | continue; | |
5862 | ||
5863 | for (i = 0; i < MAX_NUMNODES; i++) { | |
5864 | cpumask_t nodemask = node_to_cpumask(i); | |
5865 | struct sched_group *oldsg, *sg = sched_group_nodes[i]; | |
5866 | ||
5867 | cpus_and(nodemask, nodemask, *cpu_map); | |
5868 | if (cpus_empty(nodemask)) | |
5869 | continue; | |
5870 | ||
5871 | if (sg == NULL) | |
5872 | continue; | |
5873 | sg = sg->next; | |
5874 | next_sg: | |
5875 | oldsg = sg; | |
5876 | sg = sg->next; | |
5877 | kfree(oldsg); | |
5878 | if (oldsg != sched_group_nodes[i]) | |
5879 | goto next_sg; | |
5880 | } | |
5881 | kfree(sched_group_nodes); | |
5882 | sched_group_nodes_bycpu[cpu] = NULL; | |
5883 | } | |
51888ca2 | 5884 | } |
a616058b SS |
5885 | #else |
5886 | static void free_sched_groups(const cpumask_t *cpu_map) | |
5887 | { | |
5888 | } | |
5889 | #endif | |
51888ca2 | 5890 | |
89c4710e SS |
5891 | /* |
5892 | * Initialize sched groups cpu_power. | |
5893 | * | |
5894 | * cpu_power indicates the capacity of sched group, which is used while | |
5895 | * distributing the load between different sched groups in a sched domain. | |
5896 | * Typically cpu_power for all the groups in a sched domain will be same unless | |
5897 | * there are asymmetries in the topology. If there are asymmetries, group | |
5898 | * having more cpu_power will pickup more load compared to the group having | |
5899 | * less cpu_power. | |
5900 | * | |
5901 | * cpu_power will be a multiple of SCHED_LOAD_SCALE. This multiple represents | |
5902 | * the maximum number of tasks a group can handle in the presence of other idle | |
5903 | * or lightly loaded groups in the same sched domain. | |
5904 | */ | |
5905 | static void init_sched_groups_power(int cpu, struct sched_domain *sd) | |
5906 | { | |
5907 | struct sched_domain *child; | |
5908 | struct sched_group *group; | |
5909 | ||
5910 | WARN_ON(!sd || !sd->groups); | |
5911 | ||
5912 | if (cpu != first_cpu(sd->groups->cpumask)) | |
5913 | return; | |
5914 | ||
5915 | child = sd->child; | |
5916 | ||
5517d86b ED |
5917 | sd->groups->__cpu_power = 0; |
5918 | ||
89c4710e SS |
5919 | /* |
5920 | * For perf policy, if the groups in child domain share resources | |
5921 | * (for example cores sharing some portions of the cache hierarchy | |
5922 | * or SMT), then set this domain groups cpu_power such that each group | |
5923 | * can handle only one task, when there are other idle groups in the | |
5924 | * same sched domain. | |
5925 | */ | |
5926 | if (!child || (!(sd->flags & SD_POWERSAVINGS_BALANCE) && | |
5927 | (child->flags & | |
5928 | (SD_SHARE_CPUPOWER | SD_SHARE_PKG_RESOURCES)))) { | |
5517d86b | 5929 | sg_inc_cpu_power(sd->groups, SCHED_LOAD_SCALE); |
89c4710e SS |
5930 | return; |
5931 | } | |
5932 | ||
89c4710e SS |
5933 | /* |
5934 | * add cpu_power of each child group to this groups cpu_power | |
5935 | */ | |
5936 | group = child->groups; | |
5937 | do { | |
5517d86b | 5938 | sg_inc_cpu_power(sd->groups, group->__cpu_power); |
89c4710e SS |
5939 | group = group->next; |
5940 | } while (group != child->groups); | |
5941 | } | |
5942 | ||
1da177e4 | 5943 | /* |
1a20ff27 DG |
5944 | * Build sched domains for a given set of cpus and attach the sched domains |
5945 | * to the individual cpus | |
1da177e4 | 5946 | */ |
51888ca2 | 5947 | static int build_sched_domains(const cpumask_t *cpu_map) |
1da177e4 LT |
5948 | { |
5949 | int i; | |
d1b55138 JH |
5950 | #ifdef CONFIG_NUMA |
5951 | struct sched_group **sched_group_nodes = NULL; | |
6711cab4 | 5952 | int sd_allnodes = 0; |
d1b55138 JH |
5953 | |
5954 | /* | |
5955 | * Allocate the per-node list of sched groups | |
5956 | */ | |
dd41f596 | 5957 | sched_group_nodes = kzalloc(sizeof(struct sched_group *)*MAX_NUMNODES, |
d3a5aa98 | 5958 | GFP_KERNEL); |
d1b55138 JH |
5959 | if (!sched_group_nodes) { |
5960 | printk(KERN_WARNING "Can not alloc sched group node list\n"); | |
51888ca2 | 5961 | return -ENOMEM; |
d1b55138 JH |
5962 | } |
5963 | sched_group_nodes_bycpu[first_cpu(*cpu_map)] = sched_group_nodes; | |
5964 | #endif | |
1da177e4 LT |
5965 | |
5966 | /* | |
1a20ff27 | 5967 | * Set up domains for cpus specified by the cpu_map. |
1da177e4 | 5968 | */ |
1a20ff27 | 5969 | for_each_cpu_mask(i, *cpu_map) { |
1da177e4 LT |
5970 | struct sched_domain *sd = NULL, *p; |
5971 | cpumask_t nodemask = node_to_cpumask(cpu_to_node(i)); | |
5972 | ||
1a20ff27 | 5973 | cpus_and(nodemask, nodemask, *cpu_map); |
1da177e4 LT |
5974 | |
5975 | #ifdef CONFIG_NUMA | |
dd41f596 IM |
5976 | if (cpus_weight(*cpu_map) > |
5977 | SD_NODES_PER_DOMAIN*cpus_weight(nodemask)) { | |
9c1cfda2 JH |
5978 | sd = &per_cpu(allnodes_domains, i); |
5979 | *sd = SD_ALLNODES_INIT; | |
5980 | sd->span = *cpu_map; | |
6711cab4 | 5981 | cpu_to_allnodes_group(i, cpu_map, &sd->groups); |
9c1cfda2 | 5982 | p = sd; |
6711cab4 | 5983 | sd_allnodes = 1; |
9c1cfda2 JH |
5984 | } else |
5985 | p = NULL; | |
5986 | ||
1da177e4 | 5987 | sd = &per_cpu(node_domains, i); |
1da177e4 | 5988 | *sd = SD_NODE_INIT; |
9c1cfda2 JH |
5989 | sd->span = sched_domain_node_span(cpu_to_node(i)); |
5990 | sd->parent = p; | |
1a848870 SS |
5991 | if (p) |
5992 | p->child = sd; | |
9c1cfda2 | 5993 | cpus_and(sd->span, sd->span, *cpu_map); |
1da177e4 LT |
5994 | #endif |
5995 | ||
5996 | p = sd; | |
5997 | sd = &per_cpu(phys_domains, i); | |
1da177e4 LT |
5998 | *sd = SD_CPU_INIT; |
5999 | sd->span = nodemask; | |
6000 | sd->parent = p; | |
1a848870 SS |
6001 | if (p) |
6002 | p->child = sd; | |
6711cab4 | 6003 | cpu_to_phys_group(i, cpu_map, &sd->groups); |
1da177e4 | 6004 | |
1e9f28fa SS |
6005 | #ifdef CONFIG_SCHED_MC |
6006 | p = sd; | |
6007 | sd = &per_cpu(core_domains, i); | |
1e9f28fa SS |
6008 | *sd = SD_MC_INIT; |
6009 | sd->span = cpu_coregroup_map(i); | |
6010 | cpus_and(sd->span, sd->span, *cpu_map); | |
6011 | sd->parent = p; | |
1a848870 | 6012 | p->child = sd; |
6711cab4 | 6013 | cpu_to_core_group(i, cpu_map, &sd->groups); |
1e9f28fa SS |
6014 | #endif |
6015 | ||
1da177e4 LT |
6016 | #ifdef CONFIG_SCHED_SMT |
6017 | p = sd; | |
6018 | sd = &per_cpu(cpu_domains, i); | |
1da177e4 LT |
6019 | *sd = SD_SIBLING_INIT; |
6020 | sd->span = cpu_sibling_map[i]; | |
1a20ff27 | 6021 | cpus_and(sd->span, sd->span, *cpu_map); |
1da177e4 | 6022 | sd->parent = p; |
1a848870 | 6023 | p->child = sd; |
6711cab4 | 6024 | cpu_to_cpu_group(i, cpu_map, &sd->groups); |
1da177e4 LT |
6025 | #endif |
6026 | } | |
6027 | ||
6028 | #ifdef CONFIG_SCHED_SMT | |
6029 | /* Set up CPU (sibling) groups */ | |
9c1cfda2 | 6030 | for_each_cpu_mask(i, *cpu_map) { |
1da177e4 | 6031 | cpumask_t this_sibling_map = cpu_sibling_map[i]; |
1a20ff27 | 6032 | cpus_and(this_sibling_map, this_sibling_map, *cpu_map); |
1da177e4 LT |
6033 | if (i != first_cpu(this_sibling_map)) |
6034 | continue; | |
6035 | ||
dd41f596 IM |
6036 | init_sched_build_groups(this_sibling_map, cpu_map, |
6037 | &cpu_to_cpu_group); | |
1da177e4 LT |
6038 | } |
6039 | #endif | |
6040 | ||
1e9f28fa SS |
6041 | #ifdef CONFIG_SCHED_MC |
6042 | /* Set up multi-core groups */ | |
6043 | for_each_cpu_mask(i, *cpu_map) { | |
6044 | cpumask_t this_core_map = cpu_coregroup_map(i); | |
6045 | cpus_and(this_core_map, this_core_map, *cpu_map); | |
6046 | if (i != first_cpu(this_core_map)) | |
6047 | continue; | |
dd41f596 IM |
6048 | init_sched_build_groups(this_core_map, cpu_map, |
6049 | &cpu_to_core_group); | |
1e9f28fa SS |
6050 | } |
6051 | #endif | |
6052 | ||
1da177e4 LT |
6053 | /* Set up physical groups */ |
6054 | for (i = 0; i < MAX_NUMNODES; i++) { | |
6055 | cpumask_t nodemask = node_to_cpumask(i); | |
6056 | ||
1a20ff27 | 6057 | cpus_and(nodemask, nodemask, *cpu_map); |
1da177e4 LT |
6058 | if (cpus_empty(nodemask)) |
6059 | continue; | |
6060 | ||
6711cab4 | 6061 | init_sched_build_groups(nodemask, cpu_map, &cpu_to_phys_group); |
1da177e4 LT |
6062 | } |
6063 | ||
6064 | #ifdef CONFIG_NUMA | |
6065 | /* Set up node groups */ | |
6711cab4 | 6066 | if (sd_allnodes) |
dd41f596 IM |
6067 | init_sched_build_groups(*cpu_map, cpu_map, |
6068 | &cpu_to_allnodes_group); | |
9c1cfda2 JH |
6069 | |
6070 | for (i = 0; i < MAX_NUMNODES; i++) { | |
6071 | /* Set up node groups */ | |
6072 | struct sched_group *sg, *prev; | |
6073 | cpumask_t nodemask = node_to_cpumask(i); | |
6074 | cpumask_t domainspan; | |
6075 | cpumask_t covered = CPU_MASK_NONE; | |
6076 | int j; | |
6077 | ||
6078 | cpus_and(nodemask, nodemask, *cpu_map); | |
d1b55138 JH |
6079 | if (cpus_empty(nodemask)) { |
6080 | sched_group_nodes[i] = NULL; | |
9c1cfda2 | 6081 | continue; |
d1b55138 | 6082 | } |
9c1cfda2 JH |
6083 | |
6084 | domainspan = sched_domain_node_span(i); | |
6085 | cpus_and(domainspan, domainspan, *cpu_map); | |
6086 | ||
15f0b676 | 6087 | sg = kmalloc_node(sizeof(struct sched_group), GFP_KERNEL, i); |
51888ca2 SV |
6088 | if (!sg) { |
6089 | printk(KERN_WARNING "Can not alloc domain group for " | |
6090 | "node %d\n", i); | |
6091 | goto error; | |
6092 | } | |
9c1cfda2 JH |
6093 | sched_group_nodes[i] = sg; |
6094 | for_each_cpu_mask(j, nodemask) { | |
6095 | struct sched_domain *sd; | |
9761eea8 | 6096 | |
9c1cfda2 JH |
6097 | sd = &per_cpu(node_domains, j); |
6098 | sd->groups = sg; | |
9c1cfda2 | 6099 | } |
5517d86b | 6100 | sg->__cpu_power = 0; |
9c1cfda2 | 6101 | sg->cpumask = nodemask; |
51888ca2 | 6102 | sg->next = sg; |
9c1cfda2 JH |
6103 | cpus_or(covered, covered, nodemask); |
6104 | prev = sg; | |
6105 | ||
6106 | for (j = 0; j < MAX_NUMNODES; j++) { | |
6107 | cpumask_t tmp, notcovered; | |
6108 | int n = (i + j) % MAX_NUMNODES; | |
6109 | ||
6110 | cpus_complement(notcovered, covered); | |
6111 | cpus_and(tmp, notcovered, *cpu_map); | |
6112 | cpus_and(tmp, tmp, domainspan); | |
6113 | if (cpus_empty(tmp)) | |
6114 | break; | |
6115 | ||
6116 | nodemask = node_to_cpumask(n); | |
6117 | cpus_and(tmp, tmp, nodemask); | |
6118 | if (cpus_empty(tmp)) | |
6119 | continue; | |
6120 | ||
15f0b676 SV |
6121 | sg = kmalloc_node(sizeof(struct sched_group), |
6122 | GFP_KERNEL, i); | |
9c1cfda2 JH |
6123 | if (!sg) { |
6124 | printk(KERN_WARNING | |
6125 | "Can not alloc domain group for node %d\n", j); | |
51888ca2 | 6126 | goto error; |
9c1cfda2 | 6127 | } |
5517d86b | 6128 | sg->__cpu_power = 0; |
9c1cfda2 | 6129 | sg->cpumask = tmp; |
51888ca2 | 6130 | sg->next = prev->next; |
9c1cfda2 JH |
6131 | cpus_or(covered, covered, tmp); |
6132 | prev->next = sg; | |
6133 | prev = sg; | |
6134 | } | |
9c1cfda2 | 6135 | } |
1da177e4 LT |
6136 | #endif |
6137 | ||
6138 | /* Calculate CPU power for physical packages and nodes */ | |
5c45bf27 | 6139 | #ifdef CONFIG_SCHED_SMT |
1a20ff27 | 6140 | for_each_cpu_mask(i, *cpu_map) { |
dd41f596 IM |
6141 | struct sched_domain *sd = &per_cpu(cpu_domains, i); |
6142 | ||
89c4710e | 6143 | init_sched_groups_power(i, sd); |
5c45bf27 | 6144 | } |
1da177e4 | 6145 | #endif |
1e9f28fa | 6146 | #ifdef CONFIG_SCHED_MC |
5c45bf27 | 6147 | for_each_cpu_mask(i, *cpu_map) { |
dd41f596 IM |
6148 | struct sched_domain *sd = &per_cpu(core_domains, i); |
6149 | ||
89c4710e | 6150 | init_sched_groups_power(i, sd); |
5c45bf27 SS |
6151 | } |
6152 | #endif | |
1e9f28fa | 6153 | |
5c45bf27 | 6154 | for_each_cpu_mask(i, *cpu_map) { |
dd41f596 IM |
6155 | struct sched_domain *sd = &per_cpu(phys_domains, i); |
6156 | ||
89c4710e | 6157 | init_sched_groups_power(i, sd); |
1da177e4 LT |
6158 | } |
6159 | ||
9c1cfda2 | 6160 | #ifdef CONFIG_NUMA |
08069033 SS |
6161 | for (i = 0; i < MAX_NUMNODES; i++) |
6162 | init_numa_sched_groups_power(sched_group_nodes[i]); | |
9c1cfda2 | 6163 | |
6711cab4 SS |
6164 | if (sd_allnodes) { |
6165 | struct sched_group *sg; | |
f712c0c7 | 6166 | |
6711cab4 | 6167 | cpu_to_allnodes_group(first_cpu(*cpu_map), cpu_map, &sg); |
f712c0c7 SS |
6168 | init_numa_sched_groups_power(sg); |
6169 | } | |
9c1cfda2 JH |
6170 | #endif |
6171 | ||
1da177e4 | 6172 | /* Attach the domains */ |
1a20ff27 | 6173 | for_each_cpu_mask(i, *cpu_map) { |
1da177e4 LT |
6174 | struct sched_domain *sd; |
6175 | #ifdef CONFIG_SCHED_SMT | |
6176 | sd = &per_cpu(cpu_domains, i); | |
1e9f28fa SS |
6177 | #elif defined(CONFIG_SCHED_MC) |
6178 | sd = &per_cpu(core_domains, i); | |
1da177e4 LT |
6179 | #else |
6180 | sd = &per_cpu(phys_domains, i); | |
6181 | #endif | |
6182 | cpu_attach_domain(sd, i); | |
6183 | } | |
51888ca2 SV |
6184 | |
6185 | return 0; | |
6186 | ||
a616058b | 6187 | #ifdef CONFIG_NUMA |
51888ca2 SV |
6188 | error: |
6189 | free_sched_groups(cpu_map); | |
6190 | return -ENOMEM; | |
a616058b | 6191 | #endif |
1da177e4 | 6192 | } |
1a20ff27 DG |
6193 | /* |
6194 | * Set up scheduler domains and groups. Callers must hold the hotplug lock. | |
6195 | */ | |
51888ca2 | 6196 | static int arch_init_sched_domains(const cpumask_t *cpu_map) |
1a20ff27 DG |
6197 | { |
6198 | cpumask_t cpu_default_map; | |
51888ca2 | 6199 | int err; |
1da177e4 | 6200 | |
1a20ff27 DG |
6201 | /* |
6202 | * Setup mask for cpus without special case scheduling requirements. | |
6203 | * For now this just excludes isolated cpus, but could be used to | |
6204 | * exclude other special cases in the future. | |
6205 | */ | |
6206 | cpus_andnot(cpu_default_map, *cpu_map, cpu_isolated_map); | |
6207 | ||
51888ca2 SV |
6208 | err = build_sched_domains(&cpu_default_map); |
6209 | ||
6210 | return err; | |
1a20ff27 DG |
6211 | } |
6212 | ||
6213 | static void arch_destroy_sched_domains(const cpumask_t *cpu_map) | |
1da177e4 | 6214 | { |
51888ca2 | 6215 | free_sched_groups(cpu_map); |
9c1cfda2 | 6216 | } |
1da177e4 | 6217 | |
1a20ff27 DG |
6218 | /* |
6219 | * Detach sched domains from a group of cpus specified in cpu_map | |
6220 | * These cpus will now be attached to the NULL domain | |
6221 | */ | |
858119e1 | 6222 | static void detach_destroy_domains(const cpumask_t *cpu_map) |
1a20ff27 DG |
6223 | { |
6224 | int i; | |
6225 | ||
6226 | for_each_cpu_mask(i, *cpu_map) | |
6227 | cpu_attach_domain(NULL, i); | |
6228 | synchronize_sched(); | |
6229 | arch_destroy_sched_domains(cpu_map); | |
6230 | } | |
6231 | ||
6232 | /* | |
6233 | * Partition sched domains as specified by the cpumasks below. | |
6234 | * This attaches all cpus from the cpumasks to the NULL domain, | |
6235 | * waits for a RCU quiescent period, recalculates sched | |
6236 | * domain information and then attaches them back to the | |
6237 | * correct sched domains | |
6238 | * Call with hotplug lock held | |
6239 | */ | |
51888ca2 | 6240 | int partition_sched_domains(cpumask_t *partition1, cpumask_t *partition2) |
1a20ff27 DG |
6241 | { |
6242 | cpumask_t change_map; | |
51888ca2 | 6243 | int err = 0; |
1a20ff27 DG |
6244 | |
6245 | cpus_and(*partition1, *partition1, cpu_online_map); | |
6246 | cpus_and(*partition2, *partition2, cpu_online_map); | |
6247 | cpus_or(change_map, *partition1, *partition2); | |
6248 | ||
6249 | /* Detach sched domains from all of the affected cpus */ | |
6250 | detach_destroy_domains(&change_map); | |
6251 | if (!cpus_empty(*partition1)) | |
51888ca2 SV |
6252 | err = build_sched_domains(partition1); |
6253 | if (!err && !cpus_empty(*partition2)) | |
6254 | err = build_sched_domains(partition2); | |
6255 | ||
6256 | return err; | |
1a20ff27 DG |
6257 | } |
6258 | ||
5c45bf27 | 6259 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) |
6707de00 | 6260 | static int arch_reinit_sched_domains(void) |
5c45bf27 SS |
6261 | { |
6262 | int err; | |
6263 | ||
5be9361c | 6264 | mutex_lock(&sched_hotcpu_mutex); |
5c45bf27 SS |
6265 | detach_destroy_domains(&cpu_online_map); |
6266 | err = arch_init_sched_domains(&cpu_online_map); | |
5be9361c | 6267 | mutex_unlock(&sched_hotcpu_mutex); |
5c45bf27 SS |
6268 | |
6269 | return err; | |
6270 | } | |
6271 | ||
6272 | static ssize_t sched_power_savings_store(const char *buf, size_t count, int smt) | |
6273 | { | |
6274 | int ret; | |
6275 | ||
6276 | if (buf[0] != '0' && buf[0] != '1') | |
6277 | return -EINVAL; | |
6278 | ||
6279 | if (smt) | |
6280 | sched_smt_power_savings = (buf[0] == '1'); | |
6281 | else | |
6282 | sched_mc_power_savings = (buf[0] == '1'); | |
6283 | ||
6284 | ret = arch_reinit_sched_domains(); | |
6285 | ||
6286 | return ret ? ret : count; | |
6287 | } | |
6288 | ||
5c45bf27 SS |
6289 | #ifdef CONFIG_SCHED_MC |
6290 | static ssize_t sched_mc_power_savings_show(struct sys_device *dev, char *page) | |
6291 | { | |
6292 | return sprintf(page, "%u\n", sched_mc_power_savings); | |
6293 | } | |
48f24c4d IM |
6294 | static ssize_t sched_mc_power_savings_store(struct sys_device *dev, |
6295 | const char *buf, size_t count) | |
5c45bf27 SS |
6296 | { |
6297 | return sched_power_savings_store(buf, count, 0); | |
6298 | } | |
6707de00 AB |
6299 | static SYSDEV_ATTR(sched_mc_power_savings, 0644, sched_mc_power_savings_show, |
6300 | sched_mc_power_savings_store); | |
5c45bf27 SS |
6301 | #endif |
6302 | ||
6303 | #ifdef CONFIG_SCHED_SMT | |
6304 | static ssize_t sched_smt_power_savings_show(struct sys_device *dev, char *page) | |
6305 | { | |
6306 | return sprintf(page, "%u\n", sched_smt_power_savings); | |
6307 | } | |
48f24c4d IM |
6308 | static ssize_t sched_smt_power_savings_store(struct sys_device *dev, |
6309 | const char *buf, size_t count) | |
5c45bf27 SS |
6310 | { |
6311 | return sched_power_savings_store(buf, count, 1); | |
6312 | } | |
6707de00 AB |
6313 | static SYSDEV_ATTR(sched_smt_power_savings, 0644, sched_smt_power_savings_show, |
6314 | sched_smt_power_savings_store); | |
6315 | #endif | |
6316 | ||
6317 | int sched_create_sysfs_power_savings_entries(struct sysdev_class *cls) | |
6318 | { | |
6319 | int err = 0; | |
6320 | ||
6321 | #ifdef CONFIG_SCHED_SMT | |
6322 | if (smt_capable()) | |
6323 | err = sysfs_create_file(&cls->kset.kobj, | |
6324 | &attr_sched_smt_power_savings.attr); | |
6325 | #endif | |
6326 | #ifdef CONFIG_SCHED_MC | |
6327 | if (!err && mc_capable()) | |
6328 | err = sysfs_create_file(&cls->kset.kobj, | |
6329 | &attr_sched_mc_power_savings.attr); | |
6330 | #endif | |
6331 | return err; | |
6332 | } | |
5c45bf27 SS |
6333 | #endif |
6334 | ||
1da177e4 LT |
6335 | /* |
6336 | * Force a reinitialization of the sched domains hierarchy. The domains | |
6337 | * and groups cannot be updated in place without racing with the balancing | |
41c7ce9a | 6338 | * code, so we temporarily attach all running cpus to the NULL domain |
1da177e4 LT |
6339 | * which will prevent rebalancing while the sched domains are recalculated. |
6340 | */ | |
6341 | static int update_sched_domains(struct notifier_block *nfb, | |
6342 | unsigned long action, void *hcpu) | |
6343 | { | |
1da177e4 LT |
6344 | switch (action) { |
6345 | case CPU_UP_PREPARE: | |
8bb78442 | 6346 | case CPU_UP_PREPARE_FROZEN: |
1da177e4 | 6347 | case CPU_DOWN_PREPARE: |
8bb78442 | 6348 | case CPU_DOWN_PREPARE_FROZEN: |
1a20ff27 | 6349 | detach_destroy_domains(&cpu_online_map); |
1da177e4 LT |
6350 | return NOTIFY_OK; |
6351 | ||
6352 | case CPU_UP_CANCELED: | |
8bb78442 | 6353 | case CPU_UP_CANCELED_FROZEN: |
1da177e4 | 6354 | case CPU_DOWN_FAILED: |
8bb78442 | 6355 | case CPU_DOWN_FAILED_FROZEN: |
1da177e4 | 6356 | case CPU_ONLINE: |
8bb78442 | 6357 | case CPU_ONLINE_FROZEN: |
1da177e4 | 6358 | case CPU_DEAD: |
8bb78442 | 6359 | case CPU_DEAD_FROZEN: |
1da177e4 LT |
6360 | /* |
6361 | * Fall through and re-initialise the domains. | |
6362 | */ | |
6363 | break; | |
6364 | default: | |
6365 | return NOTIFY_DONE; | |
6366 | } | |
6367 | ||
6368 | /* The hotplug lock is already held by cpu_up/cpu_down */ | |
1a20ff27 | 6369 | arch_init_sched_domains(&cpu_online_map); |
1da177e4 LT |
6370 | |
6371 | return NOTIFY_OK; | |
6372 | } | |
1da177e4 LT |
6373 | |
6374 | void __init sched_init_smp(void) | |
6375 | { | |
5c1e1767 NP |
6376 | cpumask_t non_isolated_cpus; |
6377 | ||
5be9361c | 6378 | mutex_lock(&sched_hotcpu_mutex); |
1a20ff27 | 6379 | arch_init_sched_domains(&cpu_online_map); |
e5e5673f | 6380 | cpus_andnot(non_isolated_cpus, cpu_possible_map, cpu_isolated_map); |
5c1e1767 NP |
6381 | if (cpus_empty(non_isolated_cpus)) |
6382 | cpu_set(smp_processor_id(), non_isolated_cpus); | |
5be9361c | 6383 | mutex_unlock(&sched_hotcpu_mutex); |
1da177e4 LT |
6384 | /* XXX: Theoretical race here - CPU may be hotplugged now */ |
6385 | hotcpu_notifier(update_sched_domains, 0); | |
5c1e1767 | 6386 | |
e692ab53 NP |
6387 | init_sched_domain_sysctl(); |
6388 | ||
5c1e1767 NP |
6389 | /* Move init over to a non-isolated CPU */ |
6390 | if (set_cpus_allowed(current, non_isolated_cpus) < 0) | |
6391 | BUG(); | |
1da177e4 LT |
6392 | } |
6393 | #else | |
6394 | void __init sched_init_smp(void) | |
6395 | { | |
6396 | } | |
6397 | #endif /* CONFIG_SMP */ | |
6398 | ||
6399 | int in_sched_functions(unsigned long addr) | |
6400 | { | |
6401 | /* Linker adds these: start and end of __sched functions */ | |
6402 | extern char __sched_text_start[], __sched_text_end[]; | |
48f24c4d | 6403 | |
1da177e4 LT |
6404 | return in_lock_functions(addr) || |
6405 | (addr >= (unsigned long)__sched_text_start | |
6406 | && addr < (unsigned long)__sched_text_end); | |
6407 | } | |
6408 | ||
a9957449 | 6409 | static void init_cfs_rq(struct cfs_rq *cfs_rq, struct rq *rq) |
dd41f596 IM |
6410 | { |
6411 | cfs_rq->tasks_timeline = RB_ROOT; | |
dd41f596 IM |
6412 | #ifdef CONFIG_FAIR_GROUP_SCHED |
6413 | cfs_rq->rq = rq; | |
6414 | #endif | |
67e9fb2a | 6415 | cfs_rq->min_vruntime = (u64)(-(1LL << 20)); |
dd41f596 IM |
6416 | } |
6417 | ||
1da177e4 LT |
6418 | void __init sched_init(void) |
6419 | { | |
476f3534 | 6420 | int highest_cpu = 0; |
dd41f596 IM |
6421 | int i, j; |
6422 | ||
0a945022 | 6423 | for_each_possible_cpu(i) { |
dd41f596 | 6424 | struct rt_prio_array *array; |
70b97a7f | 6425 | struct rq *rq; |
1da177e4 LT |
6426 | |
6427 | rq = cpu_rq(i); | |
6428 | spin_lock_init(&rq->lock); | |
fcb99371 | 6429 | lockdep_set_class(&rq->lock, &rq->rq_lock_key); |
7897986b | 6430 | rq->nr_running = 0; |
dd41f596 IM |
6431 | rq->clock = 1; |
6432 | init_cfs_rq(&rq->cfs, rq); | |
6433 | #ifdef CONFIG_FAIR_GROUP_SCHED | |
6434 | INIT_LIST_HEAD(&rq->leaf_cfs_rq_list); | |
3a252015 IM |
6435 | { |
6436 | struct cfs_rq *cfs_rq = &per_cpu(init_cfs_rq, i); | |
6437 | struct sched_entity *se = | |
6438 | &per_cpu(init_sched_entity, i); | |
6439 | ||
6440 | init_cfs_rq_p[i] = cfs_rq; | |
6441 | init_cfs_rq(cfs_rq, rq); | |
4cf86d77 | 6442 | cfs_rq->tg = &init_task_group; |
3a252015 | 6443 | list_add(&cfs_rq->leaf_cfs_rq_list, |
29f59db3 SV |
6444 | &rq->leaf_cfs_rq_list); |
6445 | ||
3a252015 IM |
6446 | init_sched_entity_p[i] = se; |
6447 | se->cfs_rq = &rq->cfs; | |
6448 | se->my_q = cfs_rq; | |
4cf86d77 | 6449 | se->load.weight = init_task_group_load; |
9b5b7751 | 6450 | se->load.inv_weight = |
4cf86d77 | 6451 | div64_64(1ULL<<32, init_task_group_load); |
3a252015 IM |
6452 | se->parent = NULL; |
6453 | } | |
4cf86d77 | 6454 | init_task_group.shares = init_task_group_load; |
5cb350ba | 6455 | spin_lock_init(&init_task_group.lock); |
dd41f596 | 6456 | #endif |
1da177e4 | 6457 | |
dd41f596 IM |
6458 | for (j = 0; j < CPU_LOAD_IDX_MAX; j++) |
6459 | rq->cpu_load[j] = 0; | |
1da177e4 | 6460 | #ifdef CONFIG_SMP |
41c7ce9a | 6461 | rq->sd = NULL; |
1da177e4 | 6462 | rq->active_balance = 0; |
dd41f596 | 6463 | rq->next_balance = jiffies; |
1da177e4 | 6464 | rq->push_cpu = 0; |
0a2966b4 | 6465 | rq->cpu = i; |
1da177e4 LT |
6466 | rq->migration_thread = NULL; |
6467 | INIT_LIST_HEAD(&rq->migration_queue); | |
6468 | #endif | |
6469 | atomic_set(&rq->nr_iowait, 0); | |
6470 | ||
dd41f596 IM |
6471 | array = &rq->rt.active; |
6472 | for (j = 0; j < MAX_RT_PRIO; j++) { | |
6473 | INIT_LIST_HEAD(array->queue + j); | |
6474 | __clear_bit(j, array->bitmap); | |
1da177e4 | 6475 | } |
476f3534 | 6476 | highest_cpu = i; |
dd41f596 IM |
6477 | /* delimiter for bitsearch: */ |
6478 | __set_bit(MAX_RT_PRIO, array->bitmap); | |
1da177e4 LT |
6479 | } |
6480 | ||
2dd73a4f | 6481 | set_load_weight(&init_task); |
b50f60ce | 6482 | |
e107be36 AK |
6483 | #ifdef CONFIG_PREEMPT_NOTIFIERS |
6484 | INIT_HLIST_HEAD(&init_task.preempt_notifiers); | |
6485 | #endif | |
6486 | ||
c9819f45 | 6487 | #ifdef CONFIG_SMP |
476f3534 | 6488 | nr_cpu_ids = highest_cpu + 1; |
c9819f45 CL |
6489 | open_softirq(SCHED_SOFTIRQ, run_rebalance_domains, NULL); |
6490 | #endif | |
6491 | ||
b50f60ce HC |
6492 | #ifdef CONFIG_RT_MUTEXES |
6493 | plist_head_init(&init_task.pi_waiters, &init_task.pi_lock); | |
6494 | #endif | |
6495 | ||
1da177e4 LT |
6496 | /* |
6497 | * The boot idle thread does lazy MMU switching as well: | |
6498 | */ | |
6499 | atomic_inc(&init_mm.mm_count); | |
6500 | enter_lazy_tlb(&init_mm, current); | |
6501 | ||
6502 | /* | |
6503 | * Make us the idle thread. Technically, schedule() should not be | |
6504 | * called from this thread, however somewhere below it might be, | |
6505 | * but because we are the idle thread, we just pick up running again | |
6506 | * when this runqueue becomes "idle". | |
6507 | */ | |
6508 | init_idle(current, smp_processor_id()); | |
dd41f596 IM |
6509 | /* |
6510 | * During early bootup we pretend to be a normal task: | |
6511 | */ | |
6512 | current->sched_class = &fair_sched_class; | |
1da177e4 LT |
6513 | } |
6514 | ||
6515 | #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP | |
6516 | void __might_sleep(char *file, int line) | |
6517 | { | |
48f24c4d | 6518 | #ifdef in_atomic |
1da177e4 LT |
6519 | static unsigned long prev_jiffy; /* ratelimiting */ |
6520 | ||
6521 | if ((in_atomic() || irqs_disabled()) && | |
6522 | system_state == SYSTEM_RUNNING && !oops_in_progress) { | |
6523 | if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy) | |
6524 | return; | |
6525 | prev_jiffy = jiffies; | |
91368d73 | 6526 | printk(KERN_ERR "BUG: sleeping function called from invalid" |
1da177e4 LT |
6527 | " context at %s:%d\n", file, line); |
6528 | printk("in_atomic():%d, irqs_disabled():%d\n", | |
6529 | in_atomic(), irqs_disabled()); | |
a4c410f0 | 6530 | debug_show_held_locks(current); |
3117df04 IM |
6531 | if (irqs_disabled()) |
6532 | print_irqtrace_events(current); | |
1da177e4 LT |
6533 | dump_stack(); |
6534 | } | |
6535 | #endif | |
6536 | } | |
6537 | EXPORT_SYMBOL(__might_sleep); | |
6538 | #endif | |
6539 | ||
6540 | #ifdef CONFIG_MAGIC_SYSRQ | |
3a5e4dc1 AK |
6541 | static void normalize_task(struct rq *rq, struct task_struct *p) |
6542 | { | |
6543 | int on_rq; | |
6544 | update_rq_clock(rq); | |
6545 | on_rq = p->se.on_rq; | |
6546 | if (on_rq) | |
6547 | deactivate_task(rq, p, 0); | |
6548 | __setscheduler(rq, p, SCHED_NORMAL, 0); | |
6549 | if (on_rq) { | |
6550 | activate_task(rq, p, 0); | |
6551 | resched_task(rq->curr); | |
6552 | } | |
6553 | } | |
6554 | ||
1da177e4 LT |
6555 | void normalize_rt_tasks(void) |
6556 | { | |
a0f98a1c | 6557 | struct task_struct *g, *p; |
1da177e4 | 6558 | unsigned long flags; |
70b97a7f | 6559 | struct rq *rq; |
1da177e4 LT |
6560 | |
6561 | read_lock_irq(&tasklist_lock); | |
a0f98a1c | 6562 | do_each_thread(g, p) { |
6cfb0d5d | 6563 | p->se.exec_start = 0; |
6cfb0d5d | 6564 | #ifdef CONFIG_SCHEDSTATS |
dd41f596 | 6565 | p->se.wait_start = 0; |
dd41f596 | 6566 | p->se.sleep_start = 0; |
dd41f596 | 6567 | p->se.block_start = 0; |
6cfb0d5d | 6568 | #endif |
dd41f596 IM |
6569 | task_rq(p)->clock = 0; |
6570 | ||
6571 | if (!rt_task(p)) { | |
6572 | /* | |
6573 | * Renice negative nice level userspace | |
6574 | * tasks back to 0: | |
6575 | */ | |
6576 | if (TASK_NICE(p) < 0 && p->mm) | |
6577 | set_user_nice(p, 0); | |
1da177e4 | 6578 | continue; |
dd41f596 | 6579 | } |
1da177e4 | 6580 | |
b29739f9 IM |
6581 | spin_lock_irqsave(&p->pi_lock, flags); |
6582 | rq = __task_rq_lock(p); | |
1da177e4 | 6583 | |
3a5e4dc1 AK |
6584 | if (!is_migration_thread(p, rq)) |
6585 | normalize_task(rq, p); | |
6586 | ||
b29739f9 IM |
6587 | __task_rq_unlock(rq); |
6588 | spin_unlock_irqrestore(&p->pi_lock, flags); | |
a0f98a1c IM |
6589 | } while_each_thread(g, p); |
6590 | ||
1da177e4 LT |
6591 | read_unlock_irq(&tasklist_lock); |
6592 | } | |
6593 | ||
6594 | #endif /* CONFIG_MAGIC_SYSRQ */ | |
1df5c10a LT |
6595 | |
6596 | #ifdef CONFIG_IA64 | |
6597 | /* | |
6598 | * These functions are only useful for the IA64 MCA handling. | |
6599 | * | |
6600 | * They can only be called when the whole system has been | |
6601 | * stopped - every CPU needs to be quiescent, and no scheduling | |
6602 | * activity can take place. Using them for anything else would | |
6603 | * be a serious bug, and as a result, they aren't even visible | |
6604 | * under any other configuration. | |
6605 | */ | |
6606 | ||
6607 | /** | |
6608 | * curr_task - return the current task for a given cpu. | |
6609 | * @cpu: the processor in question. | |
6610 | * | |
6611 | * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! | |
6612 | */ | |
36c8b586 | 6613 | struct task_struct *curr_task(int cpu) |
1df5c10a LT |
6614 | { |
6615 | return cpu_curr(cpu); | |
6616 | } | |
6617 | ||
6618 | /** | |
6619 | * set_curr_task - set the current task for a given cpu. | |
6620 | * @cpu: the processor in question. | |
6621 | * @p: the task pointer to set. | |
6622 | * | |
6623 | * Description: This function must only be used when non-maskable interrupts | |
6624 | * are serviced on a separate stack. It allows the architecture to switch the | |
6625 | * notion of the current task on a cpu in a non-blocking manner. This function | |
6626 | * must be called with all CPU's synchronized, and interrupts disabled, the | |
6627 | * and caller must save the original value of the current task (see | |
6628 | * curr_task() above) and restore that value before reenabling interrupts and | |
6629 | * re-starting the system. | |
6630 | * | |
6631 | * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! | |
6632 | */ | |
36c8b586 | 6633 | void set_curr_task(int cpu, struct task_struct *p) |
1df5c10a LT |
6634 | { |
6635 | cpu_curr(cpu) = p; | |
6636 | } | |
6637 | ||
6638 | #endif | |
29f59db3 SV |
6639 | |
6640 | #ifdef CONFIG_FAIR_GROUP_SCHED | |
6641 | ||
29f59db3 | 6642 | /* allocate runqueue etc for a new task group */ |
4cf86d77 | 6643 | struct task_group *sched_create_group(void) |
29f59db3 | 6644 | { |
4cf86d77 | 6645 | struct task_group *tg; |
29f59db3 SV |
6646 | struct cfs_rq *cfs_rq; |
6647 | struct sched_entity *se; | |
9b5b7751 | 6648 | struct rq *rq; |
29f59db3 SV |
6649 | int i; |
6650 | ||
29f59db3 SV |
6651 | tg = kzalloc(sizeof(*tg), GFP_KERNEL); |
6652 | if (!tg) | |
6653 | return ERR_PTR(-ENOMEM); | |
6654 | ||
9b5b7751 | 6655 | tg->cfs_rq = kzalloc(sizeof(cfs_rq) * NR_CPUS, GFP_KERNEL); |
29f59db3 SV |
6656 | if (!tg->cfs_rq) |
6657 | goto err; | |
9b5b7751 | 6658 | tg->se = kzalloc(sizeof(se) * NR_CPUS, GFP_KERNEL); |
29f59db3 SV |
6659 | if (!tg->se) |
6660 | goto err; | |
6661 | ||
6662 | for_each_possible_cpu(i) { | |
9b5b7751 | 6663 | rq = cpu_rq(i); |
29f59db3 SV |
6664 | |
6665 | cfs_rq = kmalloc_node(sizeof(struct cfs_rq), GFP_KERNEL, | |
6666 | cpu_to_node(i)); | |
6667 | if (!cfs_rq) | |
6668 | goto err; | |
6669 | ||
6670 | se = kmalloc_node(sizeof(struct sched_entity), GFP_KERNEL, | |
6671 | cpu_to_node(i)); | |
6672 | if (!se) | |
6673 | goto err; | |
6674 | ||
6675 | memset(cfs_rq, 0, sizeof(struct cfs_rq)); | |
6676 | memset(se, 0, sizeof(struct sched_entity)); | |
6677 | ||
6678 | tg->cfs_rq[i] = cfs_rq; | |
6679 | init_cfs_rq(cfs_rq, rq); | |
6680 | cfs_rq->tg = tg; | |
29f59db3 SV |
6681 | |
6682 | tg->se[i] = se; | |
6683 | se->cfs_rq = &rq->cfs; | |
6684 | se->my_q = cfs_rq; | |
6685 | se->load.weight = NICE_0_LOAD; | |
6686 | se->load.inv_weight = div64_64(1ULL<<32, NICE_0_LOAD); | |
6687 | se->parent = NULL; | |
6688 | } | |
6689 | ||
9b5b7751 SV |
6690 | for_each_possible_cpu(i) { |
6691 | rq = cpu_rq(i); | |
6692 | cfs_rq = tg->cfs_rq[i]; | |
6693 | list_add_rcu(&cfs_rq->leaf_cfs_rq_list, &rq->leaf_cfs_rq_list); | |
6694 | } | |
29f59db3 | 6695 | |
9b5b7751 | 6696 | tg->shares = NICE_0_LOAD; |
5cb350ba | 6697 | spin_lock_init(&tg->lock); |
29f59db3 | 6698 | |
9b5b7751 | 6699 | return tg; |
29f59db3 SV |
6700 | |
6701 | err: | |
6702 | for_each_possible_cpu(i) { | |
a65914b3 | 6703 | if (tg->cfs_rq) |
29f59db3 | 6704 | kfree(tg->cfs_rq[i]); |
a65914b3 | 6705 | if (tg->se) |
29f59db3 SV |
6706 | kfree(tg->se[i]); |
6707 | } | |
a65914b3 IM |
6708 | kfree(tg->cfs_rq); |
6709 | kfree(tg->se); | |
6710 | kfree(tg); | |
29f59db3 SV |
6711 | |
6712 | return ERR_PTR(-ENOMEM); | |
6713 | } | |
6714 | ||
9b5b7751 SV |
6715 | /* rcu callback to free various structures associated with a task group */ |
6716 | static void free_sched_group(struct rcu_head *rhp) | |
29f59db3 | 6717 | { |
9b5b7751 | 6718 | struct cfs_rq *cfs_rq = container_of(rhp, struct cfs_rq, rcu); |
4cf86d77 | 6719 | struct task_group *tg = cfs_rq->tg; |
29f59db3 SV |
6720 | struct sched_entity *se; |
6721 | int i; | |
6722 | ||
29f59db3 SV |
6723 | /* now it should be safe to free those cfs_rqs */ |
6724 | for_each_possible_cpu(i) { | |
6725 | cfs_rq = tg->cfs_rq[i]; | |
6726 | kfree(cfs_rq); | |
6727 | ||
6728 | se = tg->se[i]; | |
6729 | kfree(se); | |
6730 | } | |
6731 | ||
6732 | kfree(tg->cfs_rq); | |
6733 | kfree(tg->se); | |
6734 | kfree(tg); | |
6735 | } | |
6736 | ||
9b5b7751 | 6737 | /* Destroy runqueue etc associated with a task group */ |
4cf86d77 | 6738 | void sched_destroy_group(struct task_group *tg) |
29f59db3 | 6739 | { |
9b5b7751 SV |
6740 | struct cfs_rq *cfs_rq; |
6741 | int i; | |
29f59db3 | 6742 | |
9b5b7751 SV |
6743 | for_each_possible_cpu(i) { |
6744 | cfs_rq = tg->cfs_rq[i]; | |
6745 | list_del_rcu(&cfs_rq->leaf_cfs_rq_list); | |
6746 | } | |
6747 | ||
6748 | cfs_rq = tg->cfs_rq[0]; | |
6749 | ||
6750 | /* wait for possible concurrent references to cfs_rqs complete */ | |
6751 | call_rcu(&cfs_rq->rcu, free_sched_group); | |
29f59db3 SV |
6752 | } |
6753 | ||
9b5b7751 | 6754 | /* change task's runqueue when it moves between groups. |
3a252015 IM |
6755 | * The caller of this function should have put the task in its new group |
6756 | * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to | |
6757 | * reflect its new group. | |
9b5b7751 SV |
6758 | */ |
6759 | void sched_move_task(struct task_struct *tsk) | |
29f59db3 SV |
6760 | { |
6761 | int on_rq, running; | |
6762 | unsigned long flags; | |
6763 | struct rq *rq; | |
6764 | ||
6765 | rq = task_rq_lock(tsk, &flags); | |
6766 | ||
6767 | if (tsk->sched_class != &fair_sched_class) | |
6768 | goto done; | |
6769 | ||
6770 | update_rq_clock(rq); | |
6771 | ||
6772 | running = task_running(rq, tsk); | |
6773 | on_rq = tsk->se.on_rq; | |
6774 | ||
83b699ed | 6775 | if (on_rq) { |
29f59db3 | 6776 | dequeue_task(rq, tsk, 0); |
83b699ed SV |
6777 | if (unlikely(running)) |
6778 | tsk->sched_class->put_prev_task(rq, tsk); | |
6779 | } | |
29f59db3 SV |
6780 | |
6781 | set_task_cfs_rq(tsk); | |
6782 | ||
83b699ed SV |
6783 | if (on_rq) { |
6784 | if (unlikely(running)) | |
6785 | tsk->sched_class->set_curr_task(rq); | |
7074badb | 6786 | enqueue_task(rq, tsk, 0); |
83b699ed | 6787 | } |
29f59db3 SV |
6788 | |
6789 | done: | |
6790 | task_rq_unlock(rq, &flags); | |
6791 | } | |
6792 | ||
6793 | static void set_se_shares(struct sched_entity *se, unsigned long shares) | |
6794 | { | |
6795 | struct cfs_rq *cfs_rq = se->cfs_rq; | |
6796 | struct rq *rq = cfs_rq->rq; | |
6797 | int on_rq; | |
6798 | ||
6799 | spin_lock_irq(&rq->lock); | |
6800 | ||
6801 | on_rq = se->on_rq; | |
6802 | if (on_rq) | |
6803 | dequeue_entity(cfs_rq, se, 0); | |
6804 | ||
6805 | se->load.weight = shares; | |
6806 | se->load.inv_weight = div64_64((1ULL<<32), shares); | |
6807 | ||
6808 | if (on_rq) | |
6809 | enqueue_entity(cfs_rq, se, 0); | |
6810 | ||
6811 | spin_unlock_irq(&rq->lock); | |
6812 | } | |
6813 | ||
4cf86d77 | 6814 | int sched_group_set_shares(struct task_group *tg, unsigned long shares) |
29f59db3 SV |
6815 | { |
6816 | int i; | |
29f59db3 | 6817 | |
5cb350ba | 6818 | spin_lock(&tg->lock); |
9b5b7751 | 6819 | if (tg->shares == shares) |
5cb350ba | 6820 | goto done; |
29f59db3 | 6821 | |
9b5b7751 | 6822 | /* return -EINVAL if the new value is not sane */ |
29f59db3 | 6823 | |
9b5b7751 | 6824 | tg->shares = shares; |
29f59db3 | 6825 | for_each_possible_cpu(i) |
9b5b7751 | 6826 | set_se_shares(tg->se[i], shares); |
29f59db3 | 6827 | |
5cb350ba DG |
6828 | done: |
6829 | spin_unlock(&tg->lock); | |
9b5b7751 | 6830 | return 0; |
29f59db3 SV |
6831 | } |
6832 | ||
5cb350ba DG |
6833 | unsigned long sched_group_shares(struct task_group *tg) |
6834 | { | |
6835 | return tg->shares; | |
6836 | } | |
6837 | ||
3a252015 | 6838 | #endif /* CONFIG_FAIR_GROUP_SCHED */ |