4 * Kernel scheduler and related syscalls
6 * Copyright (C) 1991-2002 Linus Torvalds
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
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
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
23 * 2007-05-06 Interactivity improvements to CFS by Mike Galbraith
24 * 2007-07-01 Group scheduling enhancements by Srivatsa Vaddagiri
25 * 2007-11-29 RT balancing improvements by Steven Rostedt, Gregory Haskins,
26 * Thomas Gleixner, Mike Kravetz
30 #include <linux/module.h>
31 #include <linux/nmi.h>
32 #include <linux/init.h>
33 #include <linux/uaccess.h>
34 #include <linux/highmem.h>
35 #include <linux/smp_lock.h>
36 #include <asm/mmu_context.h>
37 #include <linux/interrupt.h>
38 #include <linux/capability.h>
39 #include <linux/completion.h>
40 #include <linux/kernel_stat.h>
41 #include <linux/debug_locks.h>
42 #include <linux/security.h>
43 #include <linux/notifier.h>
44 #include <linux/profile.h>
45 #include <linux/freezer.h>
46 #include <linux/vmalloc.h>
47 #include <linux/blkdev.h>
48 #include <linux/delay.h>
49 #include <linux/pid_namespace.h>
50 #include <linux/smp.h>
51 #include <linux/threads.h>
52 #include <linux/timer.h>
53 #include <linux/rcupdate.h>
54 #include <linux/cpu.h>
55 #include <linux/cpuset.h>
56 #include <linux/percpu.h>
57 #include <linux/kthread.h>
58 #include <linux/proc_fs.h>
59 #include <linux/seq_file.h>
60 #include <linux/sysctl.h>
61 #include <linux/syscalls.h>
62 #include <linux/times.h>
63 #include <linux/tsacct_kern.h>
64 #include <linux/kprobes.h>
65 #include <linux/delayacct.h>
66 #include <linux/reciprocal_div.h>
67 #include <linux/unistd.h>
68 #include <linux/pagemap.h>
69 #include <linux/hrtimer.h>
70 #include <linux/tick.h>
71 #include <linux/bootmem.h>
72 #include <linux/debugfs.h>
73 #include <linux/ctype.h>
74 #include <linux/ftrace.h>
75 #include <trace/sched.h>
78 #include <asm/irq_regs.h>
80 #include "sched_cpupri.h"
83 * Convert user-nice values [ -20 ... 0 ... 19 ]
84 * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
87 #define NICE_TO_PRIO(nice) (MAX_RT_PRIO + (nice) + 20)
88 #define PRIO_TO_NICE(prio) ((prio) - MAX_RT_PRIO - 20)
89 #define TASK_NICE(p) PRIO_TO_NICE((p)->static_prio)
92 * 'User priority' is the nice value converted to something we
93 * can work with better when scaling various scheduler parameters,
94 * it's a [ 0 ... 39 ] range.
96 #define USER_PRIO(p) ((p)-MAX_RT_PRIO)
97 #define TASK_USER_PRIO(p) USER_PRIO((p)->static_prio)
98 #define MAX_USER_PRIO (USER_PRIO(MAX_PRIO))
101 * Helpers for converting nanosecond timing to jiffy resolution
103 #define NS_TO_JIFFIES(TIME) ((unsigned long)(TIME) / (NSEC_PER_SEC / HZ))
105 #define NICE_0_LOAD SCHED_LOAD_SCALE
106 #define NICE_0_SHIFT SCHED_LOAD_SHIFT
109 * These are the 'tuning knobs' of the scheduler:
111 * default timeslice is 100 msecs (used only for SCHED_RR tasks).
112 * Timeslices get refilled after they expire.
114 #define DEF_TIMESLICE (100 * HZ / 1000)
117 * single value that denotes runtime == period, ie unlimited time.
119 #define RUNTIME_INF ((u64)~0ULL)
121 DEFINE_TRACE(sched_wait_task
);
122 DEFINE_TRACE(sched_wakeup
);
123 DEFINE_TRACE(sched_wakeup_new
);
124 DEFINE_TRACE(sched_switch
);
125 DEFINE_TRACE(sched_migrate_task
);
129 * Divide a load by a sched group cpu_power : (load / sg->__cpu_power)
130 * Since cpu_power is a 'constant', we can use a reciprocal divide.
132 static inline u32
sg_div_cpu_power(const struct sched_group
*sg
, u32 load
)
134 return reciprocal_divide(load
, sg
->reciprocal_cpu_power
);
138 * Each time a sched group cpu_power is changed,
139 * we must compute its reciprocal value
141 static inline void sg_inc_cpu_power(struct sched_group
*sg
, u32 val
)
143 sg
->__cpu_power
+= val
;
144 sg
->reciprocal_cpu_power
= reciprocal_value(sg
->__cpu_power
);
148 static inline int rt_policy(int policy
)
150 if (unlikely(policy
== SCHED_FIFO
|| policy
== SCHED_RR
))
155 static inline int task_has_rt_policy(struct task_struct
*p
)
157 return rt_policy(p
->policy
);
161 * This is the priority-queue data structure of the RT scheduling class:
163 struct rt_prio_array
{
164 DECLARE_BITMAP(bitmap
, MAX_RT_PRIO
+1); /* include 1 bit for delimiter */
165 struct list_head queue
[MAX_RT_PRIO
];
168 struct rt_bandwidth
{
169 /* nests inside the rq lock: */
170 spinlock_t rt_runtime_lock
;
173 struct hrtimer rt_period_timer
;
176 static struct rt_bandwidth def_rt_bandwidth
;
178 static int do_sched_rt_period_timer(struct rt_bandwidth
*rt_b
, int overrun
);
180 static enum hrtimer_restart
sched_rt_period_timer(struct hrtimer
*timer
)
182 struct rt_bandwidth
*rt_b
=
183 container_of(timer
, struct rt_bandwidth
, rt_period_timer
);
189 now
= hrtimer_cb_get_time(timer
);
190 overrun
= hrtimer_forward(timer
, now
, rt_b
->rt_period
);
195 idle
= do_sched_rt_period_timer(rt_b
, overrun
);
198 return idle
? HRTIMER_NORESTART
: HRTIMER_RESTART
;
202 void init_rt_bandwidth(struct rt_bandwidth
*rt_b
, u64 period
, u64 runtime
)
204 rt_b
->rt_period
= ns_to_ktime(period
);
205 rt_b
->rt_runtime
= runtime
;
207 spin_lock_init(&rt_b
->rt_runtime_lock
);
209 hrtimer_init(&rt_b
->rt_period_timer
,
210 CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
211 rt_b
->rt_period_timer
.function
= sched_rt_period_timer
;
214 static inline int rt_bandwidth_enabled(void)
216 return sysctl_sched_rt_runtime
>= 0;
219 static void start_rt_bandwidth(struct rt_bandwidth
*rt_b
)
223 if (rt_bandwidth_enabled() && rt_b
->rt_runtime
== RUNTIME_INF
)
226 if (hrtimer_active(&rt_b
->rt_period_timer
))
229 spin_lock(&rt_b
->rt_runtime_lock
);
231 if (hrtimer_active(&rt_b
->rt_period_timer
))
234 now
= hrtimer_cb_get_time(&rt_b
->rt_period_timer
);
235 hrtimer_forward(&rt_b
->rt_period_timer
, now
, rt_b
->rt_period
);
236 hrtimer_start_expires(&rt_b
->rt_period_timer
,
239 spin_unlock(&rt_b
->rt_runtime_lock
);
242 #ifdef CONFIG_RT_GROUP_SCHED
243 static void destroy_rt_bandwidth(struct rt_bandwidth
*rt_b
)
245 hrtimer_cancel(&rt_b
->rt_period_timer
);
250 * sched_domains_mutex serializes calls to arch_init_sched_domains,
251 * detach_destroy_domains and partition_sched_domains.
253 static DEFINE_MUTEX(sched_domains_mutex
);
255 #ifdef CONFIG_GROUP_SCHED
257 #include <linux/cgroup.h>
261 static LIST_HEAD(task_groups
);
263 /* task group related information */
265 #ifdef CONFIG_CGROUP_SCHED
266 struct cgroup_subsys_state css
;
269 #ifdef CONFIG_USER_SCHED
273 #ifdef CONFIG_FAIR_GROUP_SCHED
274 /* schedulable entities of this group on each cpu */
275 struct sched_entity
**se
;
276 /* runqueue "owned" by this group on each cpu */
277 struct cfs_rq
**cfs_rq
;
278 unsigned long shares
;
281 #ifdef CONFIG_RT_GROUP_SCHED
282 struct sched_rt_entity
**rt_se
;
283 struct rt_rq
**rt_rq
;
285 struct rt_bandwidth rt_bandwidth
;
289 struct list_head list
;
291 struct task_group
*parent
;
292 struct list_head siblings
;
293 struct list_head children
;
296 #ifdef CONFIG_USER_SCHED
298 /* Helper function to pass uid information to create_sched_user() */
299 void set_tg_uid(struct user_struct
*user
)
301 user
->tg
->uid
= user
->uid
;
306 * Every UID task group (including init_task_group aka UID-0) will
307 * be a child to this group.
309 struct task_group root_task_group
;
311 #ifdef CONFIG_FAIR_GROUP_SCHED
312 /* Default task group's sched entity on each cpu */
313 static DEFINE_PER_CPU(struct sched_entity
, init_sched_entity
);
314 /* Default task group's cfs_rq on each cpu */
315 static DEFINE_PER_CPU(struct cfs_rq
, init_cfs_rq
) ____cacheline_aligned_in_smp
;
316 #endif /* CONFIG_FAIR_GROUP_SCHED */
318 #ifdef CONFIG_RT_GROUP_SCHED
319 static DEFINE_PER_CPU(struct sched_rt_entity
, init_sched_rt_entity
);
320 static DEFINE_PER_CPU(struct rt_rq
, init_rt_rq
) ____cacheline_aligned_in_smp
;
321 #endif /* CONFIG_RT_GROUP_SCHED */
322 #else /* !CONFIG_USER_SCHED */
323 #define root_task_group init_task_group
324 #endif /* CONFIG_USER_SCHED */
326 /* task_group_lock serializes add/remove of task groups and also changes to
327 * a task group's cpu shares.
329 static DEFINE_SPINLOCK(task_group_lock
);
331 #ifdef CONFIG_FAIR_GROUP_SCHED
332 #ifdef CONFIG_USER_SCHED
333 # define INIT_TASK_GROUP_LOAD (2*NICE_0_LOAD)
334 #else /* !CONFIG_USER_SCHED */
335 # define INIT_TASK_GROUP_LOAD NICE_0_LOAD
336 #endif /* CONFIG_USER_SCHED */
339 * A weight of 0 or 1 can cause arithmetics problems.
340 * A weight of a cfs_rq is the sum of weights of which entities
341 * are queued on this cfs_rq, so a weight of a entity should not be
342 * too large, so as the shares value of a task group.
343 * (The default weight is 1024 - so there's no practical
344 * limitation from this.)
347 #define MAX_SHARES (1UL << 18)
349 static int init_task_group_load
= INIT_TASK_GROUP_LOAD
;
352 /* Default task group.
353 * Every task in system belong to this group at bootup.
355 struct task_group init_task_group
;
357 /* return group to which a task belongs */
358 static inline struct task_group
*task_group(struct task_struct
*p
)
360 struct task_group
*tg
;
362 #ifdef CONFIG_USER_SCHED
364 tg
= __task_cred(p
)->user
->tg
;
366 #elif defined(CONFIG_CGROUP_SCHED)
367 tg
= container_of(task_subsys_state(p
, cpu_cgroup_subsys_id
),
368 struct task_group
, css
);
370 tg
= &init_task_group
;
375 /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
376 static inline void set_task_rq(struct task_struct
*p
, unsigned int cpu
)
378 #ifdef CONFIG_FAIR_GROUP_SCHED
379 p
->se
.cfs_rq
= task_group(p
)->cfs_rq
[cpu
];
380 p
->se
.parent
= task_group(p
)->se
[cpu
];
383 #ifdef CONFIG_RT_GROUP_SCHED
384 p
->rt
.rt_rq
= task_group(p
)->rt_rq
[cpu
];
385 p
->rt
.parent
= task_group(p
)->rt_se
[cpu
];
391 static inline void set_task_rq(struct task_struct
*p
, unsigned int cpu
) { }
392 static inline struct task_group
*task_group(struct task_struct
*p
)
397 #endif /* CONFIG_GROUP_SCHED */
399 /* CFS-related fields in a runqueue */
401 struct load_weight load
;
402 unsigned long nr_running
;
407 struct rb_root tasks_timeline
;
408 struct rb_node
*rb_leftmost
;
410 struct list_head tasks
;
411 struct list_head
*balance_iterator
;
414 * 'curr' points to currently running entity on this cfs_rq.
415 * It is set to NULL otherwise (i.e when none are currently running).
417 struct sched_entity
*curr
, *next
, *last
;
419 unsigned int nr_spread_over
;
421 #ifdef CONFIG_FAIR_GROUP_SCHED
422 struct rq
*rq
; /* cpu runqueue to which this cfs_rq is attached */
425 * leaf cfs_rqs are those that hold tasks (lowest schedulable entity in
426 * a hierarchy). Non-leaf lrqs hold other higher schedulable entities
427 * (like users, containers etc.)
429 * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This
430 * list is used during load balance.
432 struct list_head leaf_cfs_rq_list
;
433 struct task_group
*tg
; /* group that "owns" this runqueue */
437 * the part of load.weight contributed by tasks
439 unsigned long task_weight
;
442 * h_load = weight * f(tg)
444 * Where f(tg) is the recursive weight fraction assigned to
447 unsigned long h_load
;
450 * this cpu's part of tg->shares
452 unsigned long shares
;
455 * load.weight at the time we set shares
457 unsigned long rq_weight
;
462 /* Real-Time classes' related field in a runqueue: */
464 struct rt_prio_array active
;
465 unsigned long rt_nr_running
;
466 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
467 int highest_prio
; /* highest queued rt task prio */
470 unsigned long rt_nr_migratory
;
476 /* Nests inside the rq lock: */
477 spinlock_t rt_runtime_lock
;
479 #ifdef CONFIG_RT_GROUP_SCHED
480 unsigned long rt_nr_boosted
;
483 struct list_head leaf_rt_rq_list
;
484 struct task_group
*tg
;
485 struct sched_rt_entity
*rt_se
;
492 * We add the notion of a root-domain which will be used to define per-domain
493 * variables. Each exclusive cpuset essentially defines an island domain by
494 * fully partitioning the member cpus from any other cpuset. Whenever a new
495 * exclusive cpuset is created, we also create and attach a new root-domain
502 cpumask_var_t online
;
505 * The "RT overload" flag: it gets set if a CPU has more than
506 * one runnable RT task.
508 cpumask_var_t rto_mask
;
511 struct cpupri cpupri
;
513 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
515 * Preferred wake up cpu nominated by sched_mc balance that will be
516 * used when most cpus are idle in the system indicating overall very
517 * low system utilisation. Triggered at POWERSAVINGS_BALANCE_WAKEUP(2)
519 unsigned int sched_mc_preferred_wakeup_cpu
;
524 * By default the system creates a single root-domain with all cpus as
525 * members (mimicking the global state we have today).
527 static struct root_domain def_root_domain
;
532 * This is the main, per-CPU runqueue data structure.
534 * Locking rule: those places that want to lock multiple runqueues
535 * (such as the load balancing or the thread migration code), lock
536 * acquire operations must be ordered by ascending &runqueue.
543 * nr_running and cpu_load should be in the same cacheline because
544 * remote CPUs use both these fields when doing load calculation.
546 unsigned long nr_running
;
547 #define CPU_LOAD_IDX_MAX 5
548 unsigned long cpu_load
[CPU_LOAD_IDX_MAX
];
549 unsigned char idle_at_tick
;
551 unsigned long last_tick_seen
;
552 unsigned char in_nohz_recently
;
554 /* capture load from *all* tasks on this cpu: */
555 struct load_weight load
;
556 unsigned long nr_load_updates
;
562 #ifdef CONFIG_FAIR_GROUP_SCHED
563 /* list of leaf cfs_rq on this cpu: */
564 struct list_head leaf_cfs_rq_list
;
566 #ifdef CONFIG_RT_GROUP_SCHED
567 struct list_head leaf_rt_rq_list
;
571 * This is part of a global counter where only the total sum
572 * over all CPUs matters. A task can increase this counter on
573 * one CPU and if it got migrated afterwards it may decrease
574 * it on another CPU. Always updated under the runqueue lock:
576 unsigned long nr_uninterruptible
;
578 struct task_struct
*curr
, *idle
;
579 unsigned long next_balance
;
580 struct mm_struct
*prev_mm
;
587 struct root_domain
*rd
;
588 struct sched_domain
*sd
;
590 /* For active balancing */
593 /* cpu of this runqueue: */
597 unsigned long avg_load_per_task
;
599 struct task_struct
*migration_thread
;
600 struct list_head migration_queue
;
603 #ifdef CONFIG_SCHED_HRTICK
605 int hrtick_csd_pending
;
606 struct call_single_data hrtick_csd
;
608 struct hrtimer hrtick_timer
;
611 #ifdef CONFIG_SCHEDSTATS
613 struct sched_info rq_sched_info
;
614 unsigned long long rq_cpu_time
;
615 /* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */
617 /* sys_sched_yield() stats */
618 unsigned int yld_exp_empty
;
619 unsigned int yld_act_empty
;
620 unsigned int yld_both_empty
;
621 unsigned int yld_count
;
623 /* schedule() stats */
624 unsigned int sched_switch
;
625 unsigned int sched_count
;
626 unsigned int sched_goidle
;
628 /* try_to_wake_up() stats */
629 unsigned int ttwu_count
;
630 unsigned int ttwu_local
;
633 unsigned int bkl_count
;
637 static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq
, runqueues
);
639 static inline void check_preempt_curr(struct rq
*rq
, struct task_struct
*p
, int sync
)
641 rq
->curr
->sched_class
->check_preempt_curr(rq
, p
, sync
);
644 static inline int cpu_of(struct rq
*rq
)
654 * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
655 * See detach_destroy_domains: synchronize_sched for details.
657 * The domain tree of any CPU may only be accessed from within
658 * preempt-disabled sections.
660 #define for_each_domain(cpu, __sd) \
661 for (__sd = rcu_dereference(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent)
663 #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu)))
664 #define this_rq() (&__get_cpu_var(runqueues))
665 #define task_rq(p) cpu_rq(task_cpu(p))
666 #define cpu_curr(cpu) (cpu_rq(cpu)->curr)
668 inline void update_rq_clock(struct rq
*rq
)
670 rq
->clock
= sched_clock_cpu(cpu_of(rq
));
674 * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
676 #ifdef CONFIG_SCHED_DEBUG
677 # define const_debug __read_mostly
679 # define const_debug static const
685 * Returns true if the current cpu runqueue is locked.
686 * This interface allows printk to be called with the runqueue lock
687 * held and know whether or not it is OK to wake up the klogd.
689 int runqueue_is_locked(void)
692 struct rq
*rq
= cpu_rq(cpu
);
695 ret
= spin_is_locked(&rq
->lock
);
701 * Debugging: various feature bits
704 #define SCHED_FEAT(name, enabled) \
705 __SCHED_FEAT_##name ,
708 #include "sched_features.h"
713 #define SCHED_FEAT(name, enabled) \
714 (1UL << __SCHED_FEAT_##name) * enabled |
716 const_debug
unsigned int sysctl_sched_features
=
717 #include "sched_features.h"
722 #ifdef CONFIG_SCHED_DEBUG
723 #define SCHED_FEAT(name, enabled) \
726 static __read_mostly
char *sched_feat_names
[] = {
727 #include "sched_features.h"
733 static int sched_feat_show(struct seq_file
*m
, void *v
)
737 for (i
= 0; sched_feat_names
[i
]; i
++) {
738 if (!(sysctl_sched_features
& (1UL << i
)))
740 seq_printf(m
, "%s ", sched_feat_names
[i
]);
748 sched_feat_write(struct file
*filp
, const char __user
*ubuf
,
749 size_t cnt
, loff_t
*ppos
)
759 if (copy_from_user(&buf
, ubuf
, cnt
))
764 if (strncmp(buf
, "NO_", 3) == 0) {
769 for (i
= 0; sched_feat_names
[i
]; i
++) {
770 int len
= strlen(sched_feat_names
[i
]);
772 if (strncmp(cmp
, sched_feat_names
[i
], len
) == 0) {
774 sysctl_sched_features
&= ~(1UL << i
);
776 sysctl_sched_features
|= (1UL << i
);
781 if (!sched_feat_names
[i
])
789 static int sched_feat_open(struct inode
*inode
, struct file
*filp
)
791 return single_open(filp
, sched_feat_show
, NULL
);
794 static struct file_operations sched_feat_fops
= {
795 .open
= sched_feat_open
,
796 .write
= sched_feat_write
,
799 .release
= single_release
,
802 static __init
int sched_init_debug(void)
804 debugfs_create_file("sched_features", 0644, NULL
, NULL
,
809 late_initcall(sched_init_debug
);
813 #define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
816 * Number of tasks to iterate in a single balance run.
817 * Limited because this is done with IRQs disabled.
819 const_debug
unsigned int sysctl_sched_nr_migrate
= 32;
822 * ratelimit for updating the group shares.
825 unsigned int sysctl_sched_shares_ratelimit
= 250000;
828 * Inject some fuzzyness into changing the per-cpu group shares
829 * this avoids remote rq-locks at the expense of fairness.
832 unsigned int sysctl_sched_shares_thresh
= 4;
835 * period over which we measure -rt task cpu usage in us.
838 unsigned int sysctl_sched_rt_period
= 1000000;
840 static __read_mostly
int scheduler_running
;
843 * part of the period that we allow rt tasks to run in us.
846 int sysctl_sched_rt_runtime
= 950000;
848 static inline u64
global_rt_period(void)
850 return (u64
)sysctl_sched_rt_period
* NSEC_PER_USEC
;
853 static inline u64
global_rt_runtime(void)
855 if (sysctl_sched_rt_runtime
< 0)
858 return (u64
)sysctl_sched_rt_runtime
* NSEC_PER_USEC
;
861 #ifndef prepare_arch_switch
862 # define prepare_arch_switch(next) do { } while (0)
864 #ifndef finish_arch_switch
865 # define finish_arch_switch(prev) do { } while (0)
868 static inline int task_current(struct rq
*rq
, struct task_struct
*p
)
870 return rq
->curr
== p
;
873 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
874 static inline int task_running(struct rq
*rq
, struct task_struct
*p
)
876 return task_current(rq
, p
);
879 static inline void prepare_lock_switch(struct rq
*rq
, struct task_struct
*next
)
883 static inline void finish_lock_switch(struct rq
*rq
, struct task_struct
*prev
)
885 #ifdef CONFIG_DEBUG_SPINLOCK
886 /* this is a valid case when another task releases the spinlock */
887 rq
->lock
.owner
= current
;
890 * If we are tracking spinlock dependencies then we have to
891 * fix up the runqueue lock - which gets 'carried over' from
894 spin_acquire(&rq
->lock
.dep_map
, 0, 0, _THIS_IP_
);
896 spin_unlock_irq(&rq
->lock
);
899 #else /* __ARCH_WANT_UNLOCKED_CTXSW */
900 static inline int task_running(struct rq
*rq
, struct task_struct
*p
)
905 return task_current(rq
, p
);
909 static inline void prepare_lock_switch(struct rq
*rq
, struct task_struct
*next
)
913 * We can optimise this out completely for !SMP, because the
914 * SMP rebalancing from interrupt is the only thing that cares
919 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
920 spin_unlock_irq(&rq
->lock
);
922 spin_unlock(&rq
->lock
);
926 static inline void finish_lock_switch(struct rq
*rq
, struct task_struct
*prev
)
930 * After ->oncpu is cleared, the task can be moved to a different CPU.
931 * We must ensure this doesn't happen until the switch is completely
937 #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW
941 #endif /* __ARCH_WANT_UNLOCKED_CTXSW */
944 * __task_rq_lock - lock the runqueue a given task resides on.
945 * Must be called interrupts disabled.
947 static inline struct rq
*__task_rq_lock(struct task_struct
*p
)
951 struct rq
*rq
= task_rq(p
);
952 spin_lock(&rq
->lock
);
953 if (likely(rq
== task_rq(p
)))
955 spin_unlock(&rq
->lock
);
960 * task_rq_lock - lock the runqueue a given task resides on and disable
961 * interrupts. Note the ordering: we can safely lookup the task_rq without
962 * explicitly disabling preemption.
964 static struct rq
*task_rq_lock(struct task_struct
*p
, unsigned long *flags
)
970 local_irq_save(*flags
);
972 spin_lock(&rq
->lock
);
973 if (likely(rq
== task_rq(p
)))
975 spin_unlock_irqrestore(&rq
->lock
, *flags
);
979 void curr_rq_lock_irq_save(unsigned long *flags
)
984 local_irq_save(*flags
);
985 rq
= cpu_rq(smp_processor_id());
986 spin_lock(&rq
->lock
);
989 void curr_rq_unlock_irq_restore(unsigned long *flags
)
994 rq
= cpu_rq(smp_processor_id());
995 spin_unlock(&rq
->lock
);
996 local_irq_restore(*flags
);
999 void task_rq_unlock_wait(struct task_struct
*p
)
1001 struct rq
*rq
= task_rq(p
);
1003 smp_mb(); /* spin-unlock-wait is not a full memory barrier */
1004 spin_unlock_wait(&rq
->lock
);
1007 static void __task_rq_unlock(struct rq
*rq
)
1008 __releases(rq
->lock
)
1010 spin_unlock(&rq
->lock
);
1013 static inline void task_rq_unlock(struct rq
*rq
, unsigned long *flags
)
1014 __releases(rq
->lock
)
1016 spin_unlock_irqrestore(&rq
->lock
, *flags
);
1020 * this_rq_lock - lock this runqueue and disable interrupts.
1022 static struct rq
*this_rq_lock(void)
1023 __acquires(rq
->lock
)
1027 local_irq_disable();
1029 spin_lock(&rq
->lock
);
1034 #ifdef CONFIG_SCHED_HRTICK
1036 * Use HR-timers to deliver accurate preemption points.
1038 * Its all a bit involved since we cannot program an hrt while holding the
1039 * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
1042 * When we get rescheduled we reprogram the hrtick_timer outside of the
1048 * - enabled by features
1049 * - hrtimer is actually high res
1051 static inline int hrtick_enabled(struct rq
*rq
)
1053 if (!sched_feat(HRTICK
))
1055 if (!cpu_active(cpu_of(rq
)))
1057 return hrtimer_is_hres_active(&rq
->hrtick_timer
);
1060 static void hrtick_clear(struct rq
*rq
)
1062 if (hrtimer_active(&rq
->hrtick_timer
))
1063 hrtimer_cancel(&rq
->hrtick_timer
);
1067 * High-resolution timer tick.
1068 * Runs from hardirq context with interrupts disabled.
1070 static enum hrtimer_restart
hrtick(struct hrtimer
*timer
)
1072 struct rq
*rq
= container_of(timer
, struct rq
, hrtick_timer
);
1074 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
1076 spin_lock(&rq
->lock
);
1077 update_rq_clock(rq
);
1078 rq
->curr
->sched_class
->task_tick(rq
, rq
->curr
, 1);
1079 spin_unlock(&rq
->lock
);
1081 return HRTIMER_NORESTART
;
1086 * called from hardirq (IPI) context
1088 static void __hrtick_start(void *arg
)
1090 struct rq
*rq
= arg
;
1092 spin_lock(&rq
->lock
);
1093 hrtimer_restart(&rq
->hrtick_timer
);
1094 rq
->hrtick_csd_pending
= 0;
1095 spin_unlock(&rq
->lock
);
1099 * Called to set the hrtick timer state.
1101 * called with rq->lock held and irqs disabled
1103 static void hrtick_start(struct rq
*rq
, u64 delay
)
1105 struct hrtimer
*timer
= &rq
->hrtick_timer
;
1106 ktime_t time
= ktime_add_ns(timer
->base
->get_time(), delay
);
1108 hrtimer_set_expires(timer
, time
);
1110 if (rq
== this_rq()) {
1111 hrtimer_restart(timer
);
1112 } else if (!rq
->hrtick_csd_pending
) {
1113 __smp_call_function_single(cpu_of(rq
), &rq
->hrtick_csd
);
1114 rq
->hrtick_csd_pending
= 1;
1119 hotplug_hrtick(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
1121 int cpu
= (int)(long)hcpu
;
1124 case CPU_UP_CANCELED
:
1125 case CPU_UP_CANCELED_FROZEN
:
1126 case CPU_DOWN_PREPARE
:
1127 case CPU_DOWN_PREPARE_FROZEN
:
1129 case CPU_DEAD_FROZEN
:
1130 hrtick_clear(cpu_rq(cpu
));
1137 static __init
void init_hrtick(void)
1139 hotcpu_notifier(hotplug_hrtick
, 0);
1143 * Called to set the hrtick timer state.
1145 * called with rq->lock held and irqs disabled
1147 static void hrtick_start(struct rq
*rq
, u64 delay
)
1149 hrtimer_start(&rq
->hrtick_timer
, ns_to_ktime(delay
), HRTIMER_MODE_REL
);
1152 static inline void init_hrtick(void)
1155 #endif /* CONFIG_SMP */
1157 static void init_rq_hrtick(struct rq
*rq
)
1160 rq
->hrtick_csd_pending
= 0;
1162 rq
->hrtick_csd
.flags
= 0;
1163 rq
->hrtick_csd
.func
= __hrtick_start
;
1164 rq
->hrtick_csd
.info
= rq
;
1167 hrtimer_init(&rq
->hrtick_timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
1168 rq
->hrtick_timer
.function
= hrtick
;
1170 #else /* CONFIG_SCHED_HRTICK */
1171 static inline void hrtick_clear(struct rq
*rq
)
1175 static inline void init_rq_hrtick(struct rq
*rq
)
1179 static inline void init_hrtick(void)
1182 #endif /* CONFIG_SCHED_HRTICK */
1185 * resched_task - mark a task 'to be rescheduled now'.
1187 * On UP this means the setting of the need_resched flag, on SMP it
1188 * might also involve a cross-CPU call to trigger the scheduler on
1193 #ifndef tsk_is_polling
1194 #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
1197 static void resched_task(struct task_struct
*p
)
1201 assert_spin_locked(&task_rq(p
)->lock
);
1203 if (unlikely(test_tsk_thread_flag(p
, TIF_NEED_RESCHED
)))
1206 set_tsk_thread_flag(p
, TIF_NEED_RESCHED
);
1209 if (cpu
== smp_processor_id())
1212 /* NEED_RESCHED must be visible before we test polling */
1214 if (!tsk_is_polling(p
))
1215 smp_send_reschedule(cpu
);
1218 static void resched_cpu(int cpu
)
1220 struct rq
*rq
= cpu_rq(cpu
);
1221 unsigned long flags
;
1223 if (!spin_trylock_irqsave(&rq
->lock
, flags
))
1225 resched_task(cpu_curr(cpu
));
1226 spin_unlock_irqrestore(&rq
->lock
, flags
);
1231 * When add_timer_on() enqueues a timer into the timer wheel of an
1232 * idle CPU then this timer might expire before the next timer event
1233 * which is scheduled to wake up that CPU. In case of a completely
1234 * idle system the next event might even be infinite time into the
1235 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
1236 * leaves the inner idle loop so the newly added timer is taken into
1237 * account when the CPU goes back to idle and evaluates the timer
1238 * wheel for the next timer event.
1240 void wake_up_idle_cpu(int cpu
)
1242 struct rq
*rq
= cpu_rq(cpu
);
1244 if (cpu
== smp_processor_id())
1248 * This is safe, as this function is called with the timer
1249 * wheel base lock of (cpu) held. When the CPU is on the way
1250 * to idle and has not yet set rq->curr to idle then it will
1251 * be serialized on the timer wheel base lock and take the new
1252 * timer into account automatically.
1254 if (rq
->curr
!= rq
->idle
)
1258 * We can set TIF_RESCHED on the idle task of the other CPU
1259 * lockless. The worst case is that the other CPU runs the
1260 * idle task through an additional NOOP schedule()
1262 set_tsk_thread_flag(rq
->idle
, TIF_NEED_RESCHED
);
1264 /* NEED_RESCHED must be visible before we test polling */
1266 if (!tsk_is_polling(rq
->idle
))
1267 smp_send_reschedule(cpu
);
1269 #endif /* CONFIG_NO_HZ */
1271 #else /* !CONFIG_SMP */
1272 static void resched_task(struct task_struct
*p
)
1274 assert_spin_locked(&task_rq(p
)->lock
);
1275 set_tsk_need_resched(p
);
1277 #endif /* CONFIG_SMP */
1279 #if BITS_PER_LONG == 32
1280 # define WMULT_CONST (~0UL)
1282 # define WMULT_CONST (1UL << 32)
1285 #define WMULT_SHIFT 32
1288 * Shift right and round:
1290 #define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y))
1293 * delta *= weight / lw
1295 static unsigned long
1296 calc_delta_mine(unsigned long delta_exec
, unsigned long weight
,
1297 struct load_weight
*lw
)
1301 if (!lw
->inv_weight
) {
1302 if (BITS_PER_LONG
> 32 && unlikely(lw
->weight
>= WMULT_CONST
))
1305 lw
->inv_weight
= 1 + (WMULT_CONST
-lw
->weight
/2)
1309 tmp
= (u64
)delta_exec
* weight
;
1311 * Check whether we'd overflow the 64-bit multiplication:
1313 if (unlikely(tmp
> WMULT_CONST
))
1314 tmp
= SRR(SRR(tmp
, WMULT_SHIFT
/2) * lw
->inv_weight
,
1317 tmp
= SRR(tmp
* lw
->inv_weight
, WMULT_SHIFT
);
1319 return (unsigned long)min(tmp
, (u64
)(unsigned long)LONG_MAX
);
1322 static inline void update_load_add(struct load_weight
*lw
, unsigned long inc
)
1328 static inline void update_load_sub(struct load_weight
*lw
, unsigned long dec
)
1335 * To aid in avoiding the subversion of "niceness" due to uneven distribution
1336 * of tasks with abnormal "nice" values across CPUs the contribution that
1337 * each task makes to its run queue's load is weighted according to its
1338 * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
1339 * scaled version of the new time slice allocation that they receive on time
1343 #define WEIGHT_IDLEPRIO 2
1344 #define WMULT_IDLEPRIO (1 << 31)
1347 * Nice levels are multiplicative, with a gentle 10% change for every
1348 * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
1349 * nice 1, it will get ~10% less CPU time than another CPU-bound task
1350 * that remained on nice 0.
1352 * The "10% effect" is relative and cumulative: from _any_ nice level,
1353 * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
1354 * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
1355 * If a task goes up by ~10% and another task goes down by ~10% then
1356 * the relative distance between them is ~25%.)
1358 static const int prio_to_weight
[40] = {
1359 /* -20 */ 88761, 71755, 56483, 46273, 36291,
1360 /* -15 */ 29154, 23254, 18705, 14949, 11916,
1361 /* -10 */ 9548, 7620, 6100, 4904, 3906,
1362 /* -5 */ 3121, 2501, 1991, 1586, 1277,
1363 /* 0 */ 1024, 820, 655, 526, 423,
1364 /* 5 */ 335, 272, 215, 172, 137,
1365 /* 10 */ 110, 87, 70, 56, 45,
1366 /* 15 */ 36, 29, 23, 18, 15,
1370 * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated.
1372 * In cases where the weight does not change often, we can use the
1373 * precalculated inverse to speed up arithmetics by turning divisions
1374 * into multiplications:
1376 static const u32 prio_to_wmult
[40] = {
1377 /* -20 */ 48388, 59856, 76040, 92818, 118348,
1378 /* -15 */ 147320, 184698, 229616, 287308, 360437,
1379 /* -10 */ 449829, 563644, 704093, 875809, 1099582,
1380 /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326,
1381 /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587,
1382 /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126,
1383 /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717,
1384 /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
1387 static void activate_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
);
1390 * runqueue iterator, to support SMP load-balancing between different
1391 * scheduling classes, without having to expose their internal data
1392 * structures to the load-balancing proper:
1394 struct rq_iterator
{
1396 struct task_struct
*(*start
)(void *);
1397 struct task_struct
*(*next
)(void *);
1401 static unsigned long
1402 balance_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
1403 unsigned long max_load_move
, struct sched_domain
*sd
,
1404 enum cpu_idle_type idle
, int *all_pinned
,
1405 int *this_best_prio
, struct rq_iterator
*iterator
);
1408 iter_move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
1409 struct sched_domain
*sd
, enum cpu_idle_type idle
,
1410 struct rq_iterator
*iterator
);
1413 #ifdef CONFIG_CGROUP_CPUACCT
1414 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
);
1416 static inline void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
) {}
1419 static inline void inc_cpu_load(struct rq
*rq
, unsigned long load
)
1421 update_load_add(&rq
->load
, load
);
1424 static inline void dec_cpu_load(struct rq
*rq
, unsigned long load
)
1426 update_load_sub(&rq
->load
, load
);
1429 #if (defined(CONFIG_SMP) && defined(CONFIG_FAIR_GROUP_SCHED)) || defined(CONFIG_RT_GROUP_SCHED)
1430 typedef int (*tg_visitor
)(struct task_group
*, void *);
1433 * Iterate the full tree, calling @down when first entering a node and @up when
1434 * leaving it for the final time.
1436 static int walk_tg_tree(tg_visitor down
, tg_visitor up
, void *data
)
1438 struct task_group
*parent
, *child
;
1442 parent
= &root_task_group
;
1444 ret
= (*down
)(parent
, data
);
1447 list_for_each_entry_rcu(child
, &parent
->children
, siblings
) {
1454 ret
= (*up
)(parent
, data
);
1459 parent
= parent
->parent
;
1468 static int tg_nop(struct task_group
*tg
, void *data
)
1475 static unsigned long source_load(int cpu
, int type
);
1476 static unsigned long target_load(int cpu
, int type
);
1477 static int task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
);
1479 static unsigned long cpu_avg_load_per_task(int cpu
)
1481 struct rq
*rq
= cpu_rq(cpu
);
1482 unsigned long nr_running
= ACCESS_ONCE(rq
->nr_running
);
1485 rq
->avg_load_per_task
= rq
->load
.weight
/ nr_running
;
1487 rq
->avg_load_per_task
= 0;
1489 return rq
->avg_load_per_task
;
1492 #ifdef CONFIG_FAIR_GROUP_SCHED
1494 static void __set_se_shares(struct sched_entity
*se
, unsigned long shares
);
1497 * Calculate and set the cpu's group shares.
1500 update_group_shares_cpu(struct task_group
*tg
, int cpu
,
1501 unsigned long sd_shares
, unsigned long sd_rq_weight
)
1503 unsigned long shares
;
1504 unsigned long rq_weight
;
1509 rq_weight
= tg
->cfs_rq
[cpu
]->rq_weight
;
1512 * \Sum shares * rq_weight
1513 * shares = -----------------------
1517 shares
= (sd_shares
* rq_weight
) / sd_rq_weight
;
1518 shares
= clamp_t(unsigned long, shares
, MIN_SHARES
, MAX_SHARES
);
1520 if (abs(shares
- tg
->se
[cpu
]->load
.weight
) >
1521 sysctl_sched_shares_thresh
) {
1522 struct rq
*rq
= cpu_rq(cpu
);
1523 unsigned long flags
;
1525 spin_lock_irqsave(&rq
->lock
, flags
);
1526 tg
->cfs_rq
[cpu
]->shares
= shares
;
1528 __set_se_shares(tg
->se
[cpu
], shares
);
1529 spin_unlock_irqrestore(&rq
->lock
, flags
);
1534 * Re-compute the task group their per cpu shares over the given domain.
1535 * This needs to be done in a bottom-up fashion because the rq weight of a
1536 * parent group depends on the shares of its child groups.
1538 static int tg_shares_up(struct task_group
*tg
, void *data
)
1540 unsigned long weight
, rq_weight
= 0;
1541 unsigned long shares
= 0;
1542 struct sched_domain
*sd
= data
;
1545 for_each_cpu(i
, sched_domain_span(sd
)) {
1547 * If there are currently no tasks on the cpu pretend there
1548 * is one of average load so that when a new task gets to
1549 * run here it will not get delayed by group starvation.
1551 weight
= tg
->cfs_rq
[i
]->load
.weight
;
1553 weight
= NICE_0_LOAD
;
1555 tg
->cfs_rq
[i
]->rq_weight
= weight
;
1556 rq_weight
+= weight
;
1557 shares
+= tg
->cfs_rq
[i
]->shares
;
1560 if ((!shares
&& rq_weight
) || shares
> tg
->shares
)
1561 shares
= tg
->shares
;
1563 if (!sd
->parent
|| !(sd
->parent
->flags
& SD_LOAD_BALANCE
))
1564 shares
= tg
->shares
;
1566 for_each_cpu(i
, sched_domain_span(sd
))
1567 update_group_shares_cpu(tg
, i
, shares
, rq_weight
);
1573 * Compute the cpu's hierarchical load factor for each task group.
1574 * This needs to be done in a top-down fashion because the load of a child
1575 * group is a fraction of its parents load.
1577 static int tg_load_down(struct task_group
*tg
, void *data
)
1580 long cpu
= (long)data
;
1583 load
= cpu_rq(cpu
)->load
.weight
;
1585 load
= tg
->parent
->cfs_rq
[cpu
]->h_load
;
1586 load
*= tg
->cfs_rq
[cpu
]->shares
;
1587 load
/= tg
->parent
->cfs_rq
[cpu
]->load
.weight
+ 1;
1590 tg
->cfs_rq
[cpu
]->h_load
= load
;
1595 static void update_shares(struct sched_domain
*sd
)
1597 u64 now
= cpu_clock(raw_smp_processor_id());
1598 s64 elapsed
= now
- sd
->last_update
;
1600 if (elapsed
>= (s64
)(u64
)sysctl_sched_shares_ratelimit
) {
1601 sd
->last_update
= now
;
1602 walk_tg_tree(tg_nop
, tg_shares_up
, sd
);
1606 static void update_shares_locked(struct rq
*rq
, struct sched_domain
*sd
)
1608 spin_unlock(&rq
->lock
);
1610 spin_lock(&rq
->lock
);
1613 static void update_h_load(long cpu
)
1615 walk_tg_tree(tg_load_down
, tg_nop
, (void *)cpu
);
1620 static inline void update_shares(struct sched_domain
*sd
)
1624 static inline void update_shares_locked(struct rq
*rq
, struct sched_domain
*sd
)
1631 * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
1633 static int double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1634 __releases(this_rq
->lock
)
1635 __acquires(busiest
->lock
)
1636 __acquires(this_rq
->lock
)
1640 if (unlikely(!irqs_disabled())) {
1641 /* printk() doesn't work good under rq->lock */
1642 spin_unlock(&this_rq
->lock
);
1645 if (unlikely(!spin_trylock(&busiest
->lock
))) {
1646 if (busiest
< this_rq
) {
1647 spin_unlock(&this_rq
->lock
);
1648 spin_lock(&busiest
->lock
);
1649 spin_lock_nested(&this_rq
->lock
, SINGLE_DEPTH_NESTING
);
1652 spin_lock_nested(&busiest
->lock
, SINGLE_DEPTH_NESTING
);
1657 static inline void double_unlock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1658 __releases(busiest
->lock
)
1660 spin_unlock(&busiest
->lock
);
1661 lock_set_subclass(&this_rq
->lock
.dep_map
, 0, _RET_IP_
);
1665 #ifdef CONFIG_FAIR_GROUP_SCHED
1666 static void cfs_rq_set_shares(struct cfs_rq
*cfs_rq
, unsigned long shares
)
1669 cfs_rq
->shares
= shares
;
1674 #include "sched_stats.h"
1675 #include "sched_idletask.c"
1676 #include "sched_fair.c"
1677 #include "sched_rt.c"
1678 #ifdef CONFIG_SCHED_DEBUG
1679 # include "sched_debug.c"
1682 #define sched_class_highest (&rt_sched_class)
1683 #define for_each_class(class) \
1684 for (class = sched_class_highest; class; class = class->next)
1686 static void inc_nr_running(struct rq
*rq
)
1691 static void dec_nr_running(struct rq
*rq
)
1696 static void set_load_weight(struct task_struct
*p
)
1698 if (task_has_rt_policy(p
)) {
1699 p
->se
.load
.weight
= prio_to_weight
[0] * 2;
1700 p
->se
.load
.inv_weight
= prio_to_wmult
[0] >> 1;
1705 * SCHED_IDLE tasks get minimal weight:
1707 if (p
->policy
== SCHED_IDLE
) {
1708 p
->se
.load
.weight
= WEIGHT_IDLEPRIO
;
1709 p
->se
.load
.inv_weight
= WMULT_IDLEPRIO
;
1713 p
->se
.load
.weight
= prio_to_weight
[p
->static_prio
- MAX_RT_PRIO
];
1714 p
->se
.load
.inv_weight
= prio_to_wmult
[p
->static_prio
- MAX_RT_PRIO
];
1717 static void update_avg(u64
*avg
, u64 sample
)
1719 s64 diff
= sample
- *avg
;
1723 static void enqueue_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
)
1725 sched_info_queued(p
);
1726 p
->sched_class
->enqueue_task(rq
, p
, wakeup
);
1730 static void dequeue_task(struct rq
*rq
, struct task_struct
*p
, int sleep
)
1732 if (sleep
&& p
->se
.last_wakeup
) {
1733 update_avg(&p
->se
.avg_overlap
,
1734 p
->se
.sum_exec_runtime
- p
->se
.last_wakeup
);
1735 p
->se
.last_wakeup
= 0;
1738 sched_info_dequeued(p
);
1739 p
->sched_class
->dequeue_task(rq
, p
, sleep
);
1744 * __normal_prio - return the priority that is based on the static prio
1746 static inline int __normal_prio(struct task_struct
*p
)
1748 return p
->static_prio
;
1752 * Calculate the expected normal priority: i.e. priority
1753 * without taking RT-inheritance into account. Might be
1754 * boosted by interactivity modifiers. Changes upon fork,
1755 * setprio syscalls, and whenever the interactivity
1756 * estimator recalculates.
1758 static inline int normal_prio(struct task_struct
*p
)
1762 if (task_has_rt_policy(p
))
1763 prio
= MAX_RT_PRIO
-1 - p
->rt_priority
;
1765 prio
= __normal_prio(p
);
1770 * Calculate the current priority, i.e. the priority
1771 * taken into account by the scheduler. This value might
1772 * be boosted by RT tasks, or might be boosted by
1773 * interactivity modifiers. Will be RT if the task got
1774 * RT-boosted. If not then it returns p->normal_prio.
1776 static int effective_prio(struct task_struct
*p
)
1778 p
->normal_prio
= normal_prio(p
);
1780 * If we are RT tasks or we were boosted to RT priority,
1781 * keep the priority unchanged. Otherwise, update priority
1782 * to the normal priority:
1784 if (!rt_prio(p
->prio
))
1785 return p
->normal_prio
;
1790 * activate_task - move a task to the runqueue.
1792 static void activate_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
)
1794 if (task_contributes_to_load(p
))
1795 rq
->nr_uninterruptible
--;
1797 enqueue_task(rq
, p
, wakeup
);
1802 * deactivate_task - remove a task from the runqueue.
1804 static void deactivate_task(struct rq
*rq
, struct task_struct
*p
, int sleep
)
1806 if (task_contributes_to_load(p
))
1807 rq
->nr_uninterruptible
++;
1809 dequeue_task(rq
, p
, sleep
);
1814 * task_curr - is this task currently executing on a CPU?
1815 * @p: the task in question.
1817 inline int task_curr(const struct task_struct
*p
)
1819 return cpu_curr(task_cpu(p
)) == p
;
1822 static inline void __set_task_cpu(struct task_struct
*p
, unsigned int cpu
)
1824 set_task_rq(p
, cpu
);
1827 * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be
1828 * successfuly executed on another CPU. We must ensure that updates of
1829 * per-task data have been completed by this moment.
1832 task_thread_info(p
)->cpu
= cpu
;
1836 static inline void check_class_changed(struct rq
*rq
, struct task_struct
*p
,
1837 const struct sched_class
*prev_class
,
1838 int oldprio
, int running
)
1840 if (prev_class
!= p
->sched_class
) {
1841 if (prev_class
->switched_from
)
1842 prev_class
->switched_from(rq
, p
, running
);
1843 p
->sched_class
->switched_to(rq
, p
, running
);
1845 p
->sched_class
->prio_changed(rq
, p
, oldprio
, running
);
1850 /* Used instead of source_load when we know the type == 0 */
1851 static unsigned long weighted_cpuload(const int cpu
)
1853 return cpu_rq(cpu
)->load
.weight
;
1857 * Is this task likely cache-hot:
1860 task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
)
1865 * Buddy candidates are cache hot:
1867 if (sched_feat(CACHE_HOT_BUDDY
) &&
1868 (&p
->se
== cfs_rq_of(&p
->se
)->next
||
1869 &p
->se
== cfs_rq_of(&p
->se
)->last
))
1872 if (p
->sched_class
!= &fair_sched_class
)
1875 if (sysctl_sched_migration_cost
== -1)
1877 if (sysctl_sched_migration_cost
== 0)
1880 delta
= now
- p
->se
.exec_start
;
1882 return delta
< (s64
)sysctl_sched_migration_cost
;
1886 void set_task_cpu(struct task_struct
*p
, unsigned int new_cpu
)
1888 int old_cpu
= task_cpu(p
);
1889 struct rq
*old_rq
= cpu_rq(old_cpu
), *new_rq
= cpu_rq(new_cpu
);
1890 struct cfs_rq
*old_cfsrq
= task_cfs_rq(p
),
1891 *new_cfsrq
= cpu_cfs_rq(old_cfsrq
, new_cpu
);
1894 clock_offset
= old_rq
->clock
- new_rq
->clock
;
1896 trace_sched_migrate_task(p
, task_cpu(p
), new_cpu
);
1898 #ifdef CONFIG_SCHEDSTATS
1899 if (p
->se
.wait_start
)
1900 p
->se
.wait_start
-= clock_offset
;
1901 if (p
->se
.sleep_start
)
1902 p
->se
.sleep_start
-= clock_offset
;
1903 if (p
->se
.block_start
)
1904 p
->se
.block_start
-= clock_offset
;
1906 if (old_cpu
!= new_cpu
) {
1907 p
->se
.nr_migrations
++;
1908 #ifdef CONFIG_SCHEDSTATS
1909 if (task_hot(p
, old_rq
->clock
, NULL
))
1910 schedstat_inc(p
, se
.nr_forced2_migrations
);
1913 p
->se
.vruntime
-= old_cfsrq
->min_vruntime
-
1914 new_cfsrq
->min_vruntime
;
1916 __set_task_cpu(p
, new_cpu
);
1919 struct migration_req
{
1920 struct list_head list
;
1922 struct task_struct
*task
;
1925 struct completion done
;
1929 * The task's runqueue lock must be held.
1930 * Returns true if you have to wait for migration thread.
1933 migrate_task(struct task_struct
*p
, int dest_cpu
, struct migration_req
*req
)
1935 struct rq
*rq
= task_rq(p
);
1938 * If the task is not on a runqueue (and not running), then
1939 * it is sufficient to simply update the task's cpu field.
1941 if (!p
->se
.on_rq
&& !task_running(rq
, p
)) {
1942 set_task_cpu(p
, dest_cpu
);
1946 init_completion(&req
->done
);
1948 req
->dest_cpu
= dest_cpu
;
1949 list_add(&req
->list
, &rq
->migration_queue
);
1955 * wait_task_inactive - wait for a thread to unschedule.
1957 * If @match_state is nonzero, it's the @p->state value just checked and
1958 * not expected to change. If it changes, i.e. @p might have woken up,
1959 * then return zero. When we succeed in waiting for @p to be off its CPU,
1960 * we return a positive number (its total switch count). If a second call
1961 * a short while later returns the same number, the caller can be sure that
1962 * @p has remained unscheduled the whole time.
1964 * The caller must ensure that the task *will* unschedule sometime soon,
1965 * else this function might spin for a *long* time. This function can't
1966 * be called with interrupts off, or it may introduce deadlock with
1967 * smp_call_function() if an IPI is sent by the same process we are
1968 * waiting to become inactive.
1970 unsigned long wait_task_inactive(struct task_struct
*p
, long match_state
)
1972 unsigned long flags
;
1979 * We do the initial early heuristics without holding
1980 * any task-queue locks at all. We'll only try to get
1981 * the runqueue lock when things look like they will
1987 * If the task is actively running on another CPU
1988 * still, just relax and busy-wait without holding
1991 * NOTE! Since we don't hold any locks, it's not
1992 * even sure that "rq" stays as the right runqueue!
1993 * But we don't care, since "task_running()" will
1994 * return false if the runqueue has changed and p
1995 * is actually now running somewhere else!
1997 while (task_running(rq
, p
)) {
1998 if (match_state
&& unlikely(p
->state
!= match_state
))
2004 * Ok, time to look more closely! We need the rq
2005 * lock now, to be *sure*. If we're wrong, we'll
2006 * just go back and repeat.
2008 rq
= task_rq_lock(p
, &flags
);
2009 trace_sched_wait_task(rq
, p
);
2010 running
= task_running(rq
, p
);
2011 on_rq
= p
->se
.on_rq
;
2013 if (!match_state
|| p
->state
== match_state
)
2014 ncsw
= p
->nvcsw
| LONG_MIN
; /* sets MSB */
2015 task_rq_unlock(rq
, &flags
);
2018 * If it changed from the expected state, bail out now.
2020 if (unlikely(!ncsw
))
2024 * Was it really running after all now that we
2025 * checked with the proper locks actually held?
2027 * Oops. Go back and try again..
2029 if (unlikely(running
)) {
2035 * It's not enough that it's not actively running,
2036 * it must be off the runqueue _entirely_, and not
2039 * So if it wa still runnable (but just not actively
2040 * running right now), it's preempted, and we should
2041 * yield - it could be a while.
2043 if (unlikely(on_rq
)) {
2044 schedule_timeout_uninterruptible(1);
2049 * Ahh, all good. It wasn't running, and it wasn't
2050 * runnable, which means that it will never become
2051 * running in the future either. We're all done!
2060 * kick_process - kick a running thread to enter/exit the kernel
2061 * @p: the to-be-kicked thread
2063 * Cause a process which is running on another CPU to enter
2064 * kernel-mode, without any delay. (to get signals handled.)
2066 * NOTE: this function doesnt have to take the runqueue lock,
2067 * because all it wants to ensure is that the remote task enters
2068 * the kernel. If the IPI races and the task has been migrated
2069 * to another CPU then no harm is done and the purpose has been
2072 void kick_process(struct task_struct
*p
)
2078 if ((cpu
!= smp_processor_id()) && task_curr(p
))
2079 smp_send_reschedule(cpu
);
2084 * Return a low guess at the load of a migration-source cpu weighted
2085 * according to the scheduling class and "nice" value.
2087 * We want to under-estimate the load of migration sources, to
2088 * balance conservatively.
2090 static unsigned long source_load(int cpu
, int type
)
2092 struct rq
*rq
= cpu_rq(cpu
);
2093 unsigned long total
= weighted_cpuload(cpu
);
2095 if (type
== 0 || !sched_feat(LB_BIAS
))
2098 return min(rq
->cpu_load
[type
-1], total
);
2102 * Return a high guess at the load of a migration-target cpu weighted
2103 * according to the scheduling class and "nice" value.
2105 static unsigned long target_load(int cpu
, int type
)
2107 struct rq
*rq
= cpu_rq(cpu
);
2108 unsigned long total
= weighted_cpuload(cpu
);
2110 if (type
== 0 || !sched_feat(LB_BIAS
))
2113 return max(rq
->cpu_load
[type
-1], total
);
2117 * find_idlest_group finds and returns the least busy CPU group within the
2120 static struct sched_group
*
2121 find_idlest_group(struct sched_domain
*sd
, struct task_struct
*p
, int this_cpu
)
2123 struct sched_group
*idlest
= NULL
, *this = NULL
, *group
= sd
->groups
;
2124 unsigned long min_load
= ULONG_MAX
, this_load
= 0;
2125 int load_idx
= sd
->forkexec_idx
;
2126 int imbalance
= 100 + (sd
->imbalance_pct
-100)/2;
2129 unsigned long load
, avg_load
;
2133 /* Skip over this group if it has no CPUs allowed */
2134 if (!cpumask_intersects(sched_group_cpus(group
),
2138 local_group
= cpumask_test_cpu(this_cpu
,
2139 sched_group_cpus(group
));
2141 /* Tally up the load of all CPUs in the group */
2144 for_each_cpu(i
, sched_group_cpus(group
)) {
2145 /* Bias balancing toward cpus of our domain */
2147 load
= source_load(i
, load_idx
);
2149 load
= target_load(i
, load_idx
);
2154 /* Adjust by relative CPU power of the group */
2155 avg_load
= sg_div_cpu_power(group
,
2156 avg_load
* SCHED_LOAD_SCALE
);
2159 this_load
= avg_load
;
2161 } else if (avg_load
< min_load
) {
2162 min_load
= avg_load
;
2165 } while (group
= group
->next
, group
!= sd
->groups
);
2167 if (!idlest
|| 100*this_load
< imbalance
*min_load
)
2173 * find_idlest_cpu - find the idlest cpu among the cpus in group.
2176 find_idlest_cpu(struct sched_group
*group
, struct task_struct
*p
, int this_cpu
)
2178 unsigned long load
, min_load
= ULONG_MAX
;
2182 /* Traverse only the allowed CPUs */
2183 for_each_cpu_and(i
, sched_group_cpus(group
), &p
->cpus_allowed
) {
2184 load
= weighted_cpuload(i
);
2186 if (load
< min_load
|| (load
== min_load
&& i
== this_cpu
)) {
2196 * sched_balance_self: balance the current task (running on cpu) in domains
2197 * that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and
2200 * Balance, ie. select the least loaded group.
2202 * Returns the target CPU number, or the same CPU if no balancing is needed.
2204 * preempt must be disabled.
2206 static int sched_balance_self(int cpu
, int flag
)
2208 struct task_struct
*t
= current
;
2209 struct sched_domain
*tmp
, *sd
= NULL
;
2211 for_each_domain(cpu
, tmp
) {
2213 * If power savings logic is enabled for a domain, stop there.
2215 if (tmp
->flags
& SD_POWERSAVINGS_BALANCE
)
2217 if (tmp
->flags
& flag
)
2225 struct sched_group
*group
;
2226 int new_cpu
, weight
;
2228 if (!(sd
->flags
& flag
)) {
2233 group
= find_idlest_group(sd
, t
, cpu
);
2239 new_cpu
= find_idlest_cpu(group
, t
, cpu
);
2240 if (new_cpu
== -1 || new_cpu
== cpu
) {
2241 /* Now try balancing at a lower domain level of cpu */
2246 /* Now try balancing at a lower domain level of new_cpu */
2248 weight
= cpumask_weight(sched_domain_span(sd
));
2250 for_each_domain(cpu
, tmp
) {
2251 if (weight
<= cpumask_weight(sched_domain_span(tmp
)))
2253 if (tmp
->flags
& flag
)
2256 /* while loop will break here if sd == NULL */
2262 #endif /* CONFIG_SMP */
2265 * task_oncpu_function_call - call a function on the cpu on which a task runs
2266 * @p: the task to evaluate
2267 * @func: the function to be called
2268 * @info: the function call argument
2270 * Calls the function @func when the task is currently running. This might
2271 * be on the current CPU, which just calls the function directly
2273 void task_oncpu_function_call(struct task_struct
*p
,
2274 void (*func
) (void *info
), void *info
)
2281 smp_call_function_single(cpu
, func
, info
, 1);
2286 * try_to_wake_up - wake up a thread
2287 * @p: the to-be-woken-up thread
2288 * @state: the mask of task states that can be woken
2289 * @sync: do a synchronous wakeup?
2291 * Put it on the run-queue if it's not already there. The "current"
2292 * thread is always on the run-queue (except when the actual
2293 * re-schedule is in progress), and as such you're allowed to do
2294 * the simpler "current->state = TASK_RUNNING" to mark yourself
2295 * runnable without the overhead of this.
2297 * returns failure only if the task is already active.
2299 static int try_to_wake_up(struct task_struct
*p
, unsigned int state
, int sync
)
2301 int cpu
, orig_cpu
, this_cpu
, success
= 0;
2302 unsigned long flags
;
2306 if (!sched_feat(SYNC_WAKEUPS
))
2310 if (sched_feat(LB_WAKEUP_UPDATE
)) {
2311 struct sched_domain
*sd
;
2313 this_cpu
= raw_smp_processor_id();
2316 for_each_domain(this_cpu
, sd
) {
2317 if (cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
2326 rq
= task_rq_lock(p
, &flags
);
2327 update_rq_clock(rq
);
2328 old_state
= p
->state
;
2329 if (!(old_state
& state
))
2337 this_cpu
= smp_processor_id();
2340 if (unlikely(task_running(rq
, p
)))
2343 cpu
= p
->sched_class
->select_task_rq(p
, sync
);
2344 if (cpu
!= orig_cpu
) {
2345 set_task_cpu(p
, cpu
);
2346 task_rq_unlock(rq
, &flags
);
2347 /* might preempt at this point */
2348 rq
= task_rq_lock(p
, &flags
);
2349 old_state
= p
->state
;
2350 if (!(old_state
& state
))
2355 this_cpu
= smp_processor_id();
2359 #ifdef CONFIG_SCHEDSTATS
2360 schedstat_inc(rq
, ttwu_count
);
2361 if (cpu
== this_cpu
)
2362 schedstat_inc(rq
, ttwu_local
);
2364 struct sched_domain
*sd
;
2365 for_each_domain(this_cpu
, sd
) {
2366 if (cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
2367 schedstat_inc(sd
, ttwu_wake_remote
);
2372 #endif /* CONFIG_SCHEDSTATS */
2375 #endif /* CONFIG_SMP */
2376 schedstat_inc(p
, se
.nr_wakeups
);
2378 schedstat_inc(p
, se
.nr_wakeups_sync
);
2379 if (orig_cpu
!= cpu
)
2380 schedstat_inc(p
, se
.nr_wakeups_migrate
);
2381 if (cpu
== this_cpu
)
2382 schedstat_inc(p
, se
.nr_wakeups_local
);
2384 schedstat_inc(p
, se
.nr_wakeups_remote
);
2385 activate_task(rq
, p
, 1);
2389 trace_sched_wakeup(rq
, p
, success
);
2390 check_preempt_curr(rq
, p
, sync
);
2392 p
->state
= TASK_RUNNING
;
2394 if (p
->sched_class
->task_wake_up
)
2395 p
->sched_class
->task_wake_up(rq
, p
);
2398 current
->se
.last_wakeup
= current
->se
.sum_exec_runtime
;
2400 task_rq_unlock(rq
, &flags
);
2405 int wake_up_process(struct task_struct
*p
)
2407 return try_to_wake_up(p
, TASK_ALL
, 0);
2409 EXPORT_SYMBOL(wake_up_process
);
2411 int wake_up_state(struct task_struct
*p
, unsigned int state
)
2413 return try_to_wake_up(p
, state
, 0);
2417 * Perform scheduler related setup for a newly forked process p.
2418 * p is forked by current.
2420 * __sched_fork() is basic setup used by init_idle() too:
2422 static void __sched_fork(struct task_struct
*p
)
2424 p
->se
.exec_start
= 0;
2425 p
->se
.sum_exec_runtime
= 0;
2426 p
->se
.prev_sum_exec_runtime
= 0;
2427 p
->se
.nr_migrations
= 0;
2428 p
->se
.last_wakeup
= 0;
2429 p
->se
.avg_overlap
= 0;
2431 #ifdef CONFIG_SCHEDSTATS
2432 p
->se
.wait_start
= 0;
2433 p
->se
.sum_sleep_runtime
= 0;
2434 p
->se
.sleep_start
= 0;
2435 p
->se
.block_start
= 0;
2436 p
->se
.sleep_max
= 0;
2437 p
->se
.block_max
= 0;
2439 p
->se
.slice_max
= 0;
2443 INIT_LIST_HEAD(&p
->rt
.run_list
);
2445 INIT_LIST_HEAD(&p
->se
.group_node
);
2447 #ifdef CONFIG_PREEMPT_NOTIFIERS
2448 INIT_HLIST_HEAD(&p
->preempt_notifiers
);
2452 * We mark the process as running here, but have not actually
2453 * inserted it onto the runqueue yet. This guarantees that
2454 * nobody will actually run it, and a signal or other external
2455 * event cannot wake it up and insert it on the runqueue either.
2457 p
->state
= TASK_RUNNING
;
2461 * fork()/clone()-time setup:
2463 void sched_fork(struct task_struct
*p
, int clone_flags
)
2465 int cpu
= get_cpu();
2470 cpu
= sched_balance_self(cpu
, SD_BALANCE_FORK
);
2472 set_task_cpu(p
, cpu
);
2475 * Make sure we do not leak PI boosting priority to the child:
2477 p
->prio
= current
->normal_prio
;
2478 if (!rt_prio(p
->prio
))
2479 p
->sched_class
= &fair_sched_class
;
2481 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
2482 if (likely(sched_info_on()))
2483 memset(&p
->sched_info
, 0, sizeof(p
->sched_info
));
2485 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
2488 #ifdef CONFIG_PREEMPT
2489 /* Want to start with kernel preemption disabled. */
2490 task_thread_info(p
)->preempt_count
= 1;
2496 * wake_up_new_task - wake up a newly created task for the first time.
2498 * This function will do some initial scheduler statistics housekeeping
2499 * that must be done for every newly created context, then puts the task
2500 * on the runqueue and wakes it.
2502 void wake_up_new_task(struct task_struct
*p
, unsigned long clone_flags
)
2504 unsigned long flags
;
2507 rq
= task_rq_lock(p
, &flags
);
2508 BUG_ON(p
->state
!= TASK_RUNNING
);
2509 update_rq_clock(rq
);
2511 p
->prio
= effective_prio(p
);
2513 if (!p
->sched_class
->task_new
|| !current
->se
.on_rq
) {
2514 activate_task(rq
, p
, 0);
2517 * Let the scheduling class do new task startup
2518 * management (if any):
2520 p
->sched_class
->task_new(rq
, p
);
2523 trace_sched_wakeup_new(rq
, p
, 1);
2524 check_preempt_curr(rq
, p
, 0);
2526 if (p
->sched_class
->task_wake_up
)
2527 p
->sched_class
->task_wake_up(rq
, p
);
2529 task_rq_unlock(rq
, &flags
);
2532 #ifdef CONFIG_PREEMPT_NOTIFIERS
2535 * preempt_notifier_register - tell me when current is being being preempted & rescheduled
2536 * @notifier: notifier struct to register
2538 void preempt_notifier_register(struct preempt_notifier
*notifier
)
2540 hlist_add_head(¬ifier
->link
, ¤t
->preempt_notifiers
);
2542 EXPORT_SYMBOL_GPL(preempt_notifier_register
);
2545 * preempt_notifier_unregister - no longer interested in preemption notifications
2546 * @notifier: notifier struct to unregister
2548 * This is safe to call from within a preemption notifier.
2550 void preempt_notifier_unregister(struct preempt_notifier
*notifier
)
2552 hlist_del(¬ifier
->link
);
2554 EXPORT_SYMBOL_GPL(preempt_notifier_unregister
);
2556 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2558 struct preempt_notifier
*notifier
;
2559 struct hlist_node
*node
;
2561 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
2562 notifier
->ops
->sched_in(notifier
, raw_smp_processor_id());
2566 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2567 struct task_struct
*next
)
2569 struct preempt_notifier
*notifier
;
2570 struct hlist_node
*node
;
2572 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
2573 notifier
->ops
->sched_out(notifier
, next
);
2576 #else /* !CONFIG_PREEMPT_NOTIFIERS */
2578 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2583 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2584 struct task_struct
*next
)
2588 #endif /* CONFIG_PREEMPT_NOTIFIERS */
2591 * prepare_task_switch - prepare to switch tasks
2592 * @rq: the runqueue preparing to switch
2593 * @prev: the current task that is being switched out
2594 * @next: the task we are going to switch to.
2596 * This is called with the rq lock held and interrupts off. It must
2597 * be paired with a subsequent finish_task_switch after the context
2600 * prepare_task_switch sets up locking and calls architecture specific
2604 prepare_task_switch(struct rq
*rq
, struct task_struct
*prev
,
2605 struct task_struct
*next
)
2607 fire_sched_out_preempt_notifiers(prev
, next
);
2608 prepare_lock_switch(rq
, next
);
2609 prepare_arch_switch(next
);
2613 * finish_task_switch - clean up after a task-switch
2614 * @rq: runqueue associated with task-switch
2615 * @prev: the thread we just switched away from.
2617 * finish_task_switch must be called after the context switch, paired
2618 * with a prepare_task_switch call before the context switch.
2619 * finish_task_switch will reconcile locking set up by prepare_task_switch,
2620 * and do any other architecture-specific cleanup actions.
2622 * Note that we may have delayed dropping an mm in context_switch(). If
2623 * so, we finish that here outside of the runqueue lock. (Doing it
2624 * with the lock held can cause deadlocks; see schedule() for
2627 static void finish_task_switch(struct rq
*rq
, struct task_struct
*prev
)
2628 __releases(rq
->lock
)
2630 struct mm_struct
*mm
= rq
->prev_mm
;
2636 * A task struct has one reference for the use as "current".
2637 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
2638 * schedule one last time. The schedule call will never return, and
2639 * the scheduled task must drop that reference.
2640 * The test for TASK_DEAD must occur while the runqueue locks are
2641 * still held, otherwise prev could be scheduled on another cpu, die
2642 * there before we look at prev->state, and then the reference would
2644 * Manfred Spraul <manfred@colorfullife.com>
2646 prev_state
= prev
->state
;
2647 finish_arch_switch(prev
);
2648 perf_counter_task_sched_in(current
, cpu_of(rq
));
2649 finish_lock_switch(rq
, prev
);
2651 if (current
->sched_class
->post_schedule
)
2652 current
->sched_class
->post_schedule(rq
);
2655 fire_sched_in_preempt_notifiers(current
);
2658 if (unlikely(prev_state
== TASK_DEAD
)) {
2660 * Remove function-return probe instances associated with this
2661 * task and put them back on the free list.
2663 kprobe_flush_task(prev
);
2664 put_task_struct(prev
);
2669 * schedule_tail - first thing a freshly forked thread must call.
2670 * @prev: the thread we just switched away from.
2672 asmlinkage
void schedule_tail(struct task_struct
*prev
)
2673 __releases(rq
->lock
)
2675 struct rq
*rq
= this_rq();
2677 finish_task_switch(rq
, prev
);
2678 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
2679 /* In this case, finish_task_switch does not reenable preemption */
2682 if (current
->set_child_tid
)
2683 put_user(task_pid_vnr(current
), current
->set_child_tid
);
2687 * context_switch - switch to the new MM and the new
2688 * thread's register state.
2691 context_switch(struct rq
*rq
, struct task_struct
*prev
,
2692 struct task_struct
*next
)
2694 struct mm_struct
*mm
, *oldmm
;
2696 prepare_task_switch(rq
, prev
, next
);
2697 trace_sched_switch(rq
, prev
, next
);
2699 oldmm
= prev
->active_mm
;
2701 * For paravirt, this is coupled with an exit in switch_to to
2702 * combine the page table reload and the switch backend into
2705 arch_enter_lazy_cpu_mode();
2707 if (unlikely(!mm
)) {
2708 next
->active_mm
= oldmm
;
2709 atomic_inc(&oldmm
->mm_count
);
2710 enter_lazy_tlb(oldmm
, next
);
2712 switch_mm(oldmm
, mm
, next
);
2714 if (unlikely(!prev
->mm
)) {
2715 prev
->active_mm
= NULL
;
2716 rq
->prev_mm
= oldmm
;
2719 * Since the runqueue lock will be released by the next
2720 * task (which is an invalid locking op but in the case
2721 * of the scheduler it's an obvious special-case), so we
2722 * do an early lockdep release here:
2724 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
2725 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
2728 /* Here we just switch the register state and the stack. */
2729 switch_to(prev
, next
, prev
);
2733 * this_rq must be evaluated again because prev may have moved
2734 * CPUs since it called schedule(), thus the 'rq' on its stack
2735 * frame will be invalid.
2737 finish_task_switch(this_rq(), prev
);
2741 * nr_running, nr_uninterruptible and nr_context_switches:
2743 * externally visible scheduler statistics: current number of runnable
2744 * threads, current number of uninterruptible-sleeping threads, total
2745 * number of context switches performed since bootup.
2747 unsigned long nr_running(void)
2749 unsigned long i
, sum
= 0;
2751 for_each_online_cpu(i
)
2752 sum
+= cpu_rq(i
)->nr_running
;
2757 unsigned long nr_uninterruptible(void)
2759 unsigned long i
, sum
= 0;
2761 for_each_possible_cpu(i
)
2762 sum
+= cpu_rq(i
)->nr_uninterruptible
;
2765 * Since we read the counters lockless, it might be slightly
2766 * inaccurate. Do not allow it to go below zero though:
2768 if (unlikely((long)sum
< 0))
2774 unsigned long long nr_context_switches(void)
2777 unsigned long long sum
= 0;
2779 for_each_possible_cpu(i
)
2780 sum
+= cpu_rq(i
)->nr_switches
;
2785 unsigned long nr_iowait(void)
2787 unsigned long i
, sum
= 0;
2789 for_each_possible_cpu(i
)
2790 sum
+= atomic_read(&cpu_rq(i
)->nr_iowait
);
2795 unsigned long nr_active(void)
2797 unsigned long i
, running
= 0, uninterruptible
= 0;
2799 for_each_online_cpu(i
) {
2800 running
+= cpu_rq(i
)->nr_running
;
2801 uninterruptible
+= cpu_rq(i
)->nr_uninterruptible
;
2804 if (unlikely((long)uninterruptible
< 0))
2805 uninterruptible
= 0;
2807 return running
+ uninterruptible
;
2811 * Update rq->cpu_load[] statistics. This function is usually called every
2812 * scheduler tick (TICK_NSEC).
2814 static void update_cpu_load(struct rq
*this_rq
)
2816 unsigned long this_load
= this_rq
->load
.weight
;
2819 this_rq
->nr_load_updates
++;
2821 /* Update our load: */
2822 for (i
= 0, scale
= 1; i
< CPU_LOAD_IDX_MAX
; i
++, scale
+= scale
) {
2823 unsigned long old_load
, new_load
;
2825 /* scale is effectively 1 << i now, and >> i divides by scale */
2827 old_load
= this_rq
->cpu_load
[i
];
2828 new_load
= this_load
;
2830 * Round up the averaging division if load is increasing. This
2831 * prevents us from getting stuck on 9 if the load is 10, for
2834 if (new_load
> old_load
)
2835 new_load
+= scale
-1;
2836 this_rq
->cpu_load
[i
] = (old_load
*(scale
-1) + new_load
) >> i
;
2843 * double_rq_lock - safely lock two runqueues
2845 * Note this does not disable interrupts like task_rq_lock,
2846 * you need to do so manually before calling.
2848 static void double_rq_lock(struct rq
*rq1
, struct rq
*rq2
)
2849 __acquires(rq1
->lock
)
2850 __acquires(rq2
->lock
)
2852 BUG_ON(!irqs_disabled());
2854 spin_lock(&rq1
->lock
);
2855 __acquire(rq2
->lock
); /* Fake it out ;) */
2858 spin_lock(&rq1
->lock
);
2859 spin_lock_nested(&rq2
->lock
, SINGLE_DEPTH_NESTING
);
2861 spin_lock(&rq2
->lock
);
2862 spin_lock_nested(&rq1
->lock
, SINGLE_DEPTH_NESTING
);
2865 update_rq_clock(rq1
);
2866 update_rq_clock(rq2
);
2870 * double_rq_unlock - safely unlock two runqueues
2872 * Note this does not restore interrupts like task_rq_unlock,
2873 * you need to do so manually after calling.
2875 static void double_rq_unlock(struct rq
*rq1
, struct rq
*rq2
)
2876 __releases(rq1
->lock
)
2877 __releases(rq2
->lock
)
2879 spin_unlock(&rq1
->lock
);
2881 spin_unlock(&rq2
->lock
);
2883 __release(rq2
->lock
);
2887 * If dest_cpu is allowed for this process, migrate the task to it.
2888 * This is accomplished by forcing the cpu_allowed mask to only
2889 * allow dest_cpu, which will force the cpu onto dest_cpu. Then
2890 * the cpu_allowed mask is restored.
2892 static void sched_migrate_task(struct task_struct
*p
, int dest_cpu
)
2894 struct migration_req req
;
2895 unsigned long flags
;
2898 rq
= task_rq_lock(p
, &flags
);
2899 if (!cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
)
2900 || unlikely(!cpu_active(dest_cpu
)))
2903 /* force the process onto the specified CPU */
2904 if (migrate_task(p
, dest_cpu
, &req
)) {
2905 /* Need to wait for migration thread (might exit: take ref). */
2906 struct task_struct
*mt
= rq
->migration_thread
;
2908 get_task_struct(mt
);
2909 task_rq_unlock(rq
, &flags
);
2910 wake_up_process(mt
);
2911 put_task_struct(mt
);
2912 wait_for_completion(&req
.done
);
2917 task_rq_unlock(rq
, &flags
);
2921 * sched_exec - execve() is a valuable balancing opportunity, because at
2922 * this point the task has the smallest effective memory and cache footprint.
2924 void sched_exec(void)
2926 int new_cpu
, this_cpu
= get_cpu();
2927 new_cpu
= sched_balance_self(this_cpu
, SD_BALANCE_EXEC
);
2929 if (new_cpu
!= this_cpu
)
2930 sched_migrate_task(current
, new_cpu
);
2934 * pull_task - move a task from a remote runqueue to the local runqueue.
2935 * Both runqueues must be locked.
2937 static void pull_task(struct rq
*src_rq
, struct task_struct
*p
,
2938 struct rq
*this_rq
, int this_cpu
)
2940 deactivate_task(src_rq
, p
, 0);
2941 set_task_cpu(p
, this_cpu
);
2942 activate_task(this_rq
, p
, 0);
2944 * Note that idle threads have a prio of MAX_PRIO, for this test
2945 * to be always true for them.
2947 check_preempt_curr(this_rq
, p
, 0);
2951 * can_migrate_task - may task p from runqueue rq be migrated to this_cpu?
2954 int can_migrate_task(struct task_struct
*p
, struct rq
*rq
, int this_cpu
,
2955 struct sched_domain
*sd
, enum cpu_idle_type idle
,
2959 * We do not migrate tasks that are:
2960 * 1) running (obviously), or
2961 * 2) cannot be migrated to this CPU due to cpus_allowed, or
2962 * 3) are cache-hot on their current CPU.
2964 if (!cpumask_test_cpu(this_cpu
, &p
->cpus_allowed
)) {
2965 schedstat_inc(p
, se
.nr_failed_migrations_affine
);
2970 if (task_running(rq
, p
)) {
2971 schedstat_inc(p
, se
.nr_failed_migrations_running
);
2976 * Aggressive migration if:
2977 * 1) task is cache cold, or
2978 * 2) too many balance attempts have failed.
2981 if (!task_hot(p
, rq
->clock
, sd
) ||
2982 sd
->nr_balance_failed
> sd
->cache_nice_tries
) {
2983 #ifdef CONFIG_SCHEDSTATS
2984 if (task_hot(p
, rq
->clock
, sd
)) {
2985 schedstat_inc(sd
, lb_hot_gained
[idle
]);
2986 schedstat_inc(p
, se
.nr_forced_migrations
);
2992 if (task_hot(p
, rq
->clock
, sd
)) {
2993 schedstat_inc(p
, se
.nr_failed_migrations_hot
);
2999 static unsigned long
3000 balance_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
3001 unsigned long max_load_move
, struct sched_domain
*sd
,
3002 enum cpu_idle_type idle
, int *all_pinned
,
3003 int *this_best_prio
, struct rq_iterator
*iterator
)
3005 int loops
= 0, pulled
= 0, pinned
= 0;
3006 struct task_struct
*p
;
3007 long rem_load_move
= max_load_move
;
3009 if (max_load_move
== 0)
3015 * Start the load-balancing iterator:
3017 p
= iterator
->start(iterator
->arg
);
3019 if (!p
|| loops
++ > sysctl_sched_nr_migrate
)
3022 if ((p
->se
.load
.weight
>> 1) > rem_load_move
||
3023 !can_migrate_task(p
, busiest
, this_cpu
, sd
, idle
, &pinned
)) {
3024 p
= iterator
->next(iterator
->arg
);
3028 pull_task(busiest
, p
, this_rq
, this_cpu
);
3030 rem_load_move
-= p
->se
.load
.weight
;
3033 * We only want to steal up to the prescribed amount of weighted load.
3035 if (rem_load_move
> 0) {
3036 if (p
->prio
< *this_best_prio
)
3037 *this_best_prio
= p
->prio
;
3038 p
= iterator
->next(iterator
->arg
);
3043 * Right now, this is one of only two places pull_task() is called,
3044 * so we can safely collect pull_task() stats here rather than
3045 * inside pull_task().
3047 schedstat_add(sd
, lb_gained
[idle
], pulled
);
3050 *all_pinned
= pinned
;
3052 return max_load_move
- rem_load_move
;
3056 * move_tasks tries to move up to max_load_move weighted load from busiest to
3057 * this_rq, as part of a balancing operation within domain "sd".
3058 * Returns 1 if successful and 0 otherwise.
3060 * Called with both runqueues locked.
3062 static int move_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
3063 unsigned long max_load_move
,
3064 struct sched_domain
*sd
, enum cpu_idle_type idle
,
3067 const struct sched_class
*class = sched_class_highest
;
3068 unsigned long total_load_moved
= 0;
3069 int this_best_prio
= this_rq
->curr
->prio
;
3073 class->load_balance(this_rq
, this_cpu
, busiest
,
3074 max_load_move
- total_load_moved
,
3075 sd
, idle
, all_pinned
, &this_best_prio
);
3076 class = class->next
;
3078 if (idle
== CPU_NEWLY_IDLE
&& this_rq
->nr_running
)
3081 } while (class && max_load_move
> total_load_moved
);
3083 return total_load_moved
> 0;
3087 iter_move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
3088 struct sched_domain
*sd
, enum cpu_idle_type idle
,
3089 struct rq_iterator
*iterator
)
3091 struct task_struct
*p
= iterator
->start(iterator
->arg
);
3095 if (can_migrate_task(p
, busiest
, this_cpu
, sd
, idle
, &pinned
)) {
3096 pull_task(busiest
, p
, this_rq
, this_cpu
);
3098 * Right now, this is only the second place pull_task()
3099 * is called, so we can safely collect pull_task()
3100 * stats here rather than inside pull_task().
3102 schedstat_inc(sd
, lb_gained
[idle
]);
3106 p
= iterator
->next(iterator
->arg
);
3113 * move_one_task tries to move exactly one task from busiest to this_rq, as
3114 * part of active balancing operations within "domain".
3115 * Returns 1 if successful and 0 otherwise.
3117 * Called with both runqueues locked.
3119 static int move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
3120 struct sched_domain
*sd
, enum cpu_idle_type idle
)
3122 const struct sched_class
*class;
3124 for (class = sched_class_highest
; class; class = class->next
)
3125 if (class->move_one_task(this_rq
, this_cpu
, busiest
, sd
, idle
))
3132 * find_busiest_group finds and returns the busiest CPU group within the
3133 * domain. It calculates and returns the amount of weighted load which
3134 * should be moved to restore balance via the imbalance parameter.
3136 static struct sched_group
*
3137 find_busiest_group(struct sched_domain
*sd
, int this_cpu
,
3138 unsigned long *imbalance
, enum cpu_idle_type idle
,
3139 int *sd_idle
, const struct cpumask
*cpus
, int *balance
)
3141 struct sched_group
*busiest
= NULL
, *this = NULL
, *group
= sd
->groups
;
3142 unsigned long max_load
, avg_load
, total_load
, this_load
, total_pwr
;
3143 unsigned long max_pull
;
3144 unsigned long busiest_load_per_task
, busiest_nr_running
;
3145 unsigned long this_load_per_task
, this_nr_running
;
3146 int load_idx
, group_imb
= 0;
3147 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3148 int power_savings_balance
= 1;
3149 unsigned long leader_nr_running
= 0, min_load_per_task
= 0;
3150 unsigned long min_nr_running
= ULONG_MAX
;
3151 struct sched_group
*group_min
= NULL
, *group_leader
= NULL
;
3154 max_load
= this_load
= total_load
= total_pwr
= 0;
3155 busiest_load_per_task
= busiest_nr_running
= 0;
3156 this_load_per_task
= this_nr_running
= 0;
3158 if (idle
== CPU_NOT_IDLE
)
3159 load_idx
= sd
->busy_idx
;
3160 else if (idle
== CPU_NEWLY_IDLE
)
3161 load_idx
= sd
->newidle_idx
;
3163 load_idx
= sd
->idle_idx
;
3166 unsigned long load
, group_capacity
, max_cpu_load
, min_cpu_load
;
3169 int __group_imb
= 0;
3170 unsigned int balance_cpu
= -1, first_idle_cpu
= 0;
3171 unsigned long sum_nr_running
, sum_weighted_load
;
3172 unsigned long sum_avg_load_per_task
;
3173 unsigned long avg_load_per_task
;
3175 local_group
= cpumask_test_cpu(this_cpu
,
3176 sched_group_cpus(group
));
3179 balance_cpu
= cpumask_first(sched_group_cpus(group
));
3181 /* Tally up the load of all CPUs in the group */
3182 sum_weighted_load
= sum_nr_running
= avg_load
= 0;
3183 sum_avg_load_per_task
= avg_load_per_task
= 0;
3186 min_cpu_load
= ~0UL;
3188 for_each_cpu_and(i
, sched_group_cpus(group
), cpus
) {
3189 struct rq
*rq
= cpu_rq(i
);
3191 if (*sd_idle
&& rq
->nr_running
)
3194 /* Bias balancing toward cpus of our domain */
3196 if (idle_cpu(i
) && !first_idle_cpu
) {
3201 load
= target_load(i
, load_idx
);
3203 load
= source_load(i
, load_idx
);
3204 if (load
> max_cpu_load
)
3205 max_cpu_load
= load
;
3206 if (min_cpu_load
> load
)
3207 min_cpu_load
= load
;
3211 sum_nr_running
+= rq
->nr_running
;
3212 sum_weighted_load
+= weighted_cpuload(i
);
3214 sum_avg_load_per_task
+= cpu_avg_load_per_task(i
);
3218 * First idle cpu or the first cpu(busiest) in this sched group
3219 * is eligible for doing load balancing at this and above
3220 * domains. In the newly idle case, we will allow all the cpu's
3221 * to do the newly idle load balance.
3223 if (idle
!= CPU_NEWLY_IDLE
&& local_group
&&
3224 balance_cpu
!= this_cpu
&& balance
) {
3229 total_load
+= avg_load
;
3230 total_pwr
+= group
->__cpu_power
;
3232 /* Adjust by relative CPU power of the group */
3233 avg_load
= sg_div_cpu_power(group
,
3234 avg_load
* SCHED_LOAD_SCALE
);
3238 * Consider the group unbalanced when the imbalance is larger
3239 * than the average weight of two tasks.
3241 * APZ: with cgroup the avg task weight can vary wildly and
3242 * might not be a suitable number - should we keep a
3243 * normalized nr_running number somewhere that negates
3246 avg_load_per_task
= sg_div_cpu_power(group
,
3247 sum_avg_load_per_task
* SCHED_LOAD_SCALE
);
3249 if ((max_cpu_load
- min_cpu_load
) > 2*avg_load_per_task
)
3252 group_capacity
= group
->__cpu_power
/ SCHED_LOAD_SCALE
;
3255 this_load
= avg_load
;
3257 this_nr_running
= sum_nr_running
;
3258 this_load_per_task
= sum_weighted_load
;
3259 } else if (avg_load
> max_load
&&
3260 (sum_nr_running
> group_capacity
|| __group_imb
)) {
3261 max_load
= avg_load
;
3263 busiest_nr_running
= sum_nr_running
;
3264 busiest_load_per_task
= sum_weighted_load
;
3265 group_imb
= __group_imb
;
3268 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3270 * Busy processors will not participate in power savings
3273 if (idle
== CPU_NOT_IDLE
||
3274 !(sd
->flags
& SD_POWERSAVINGS_BALANCE
))
3278 * If the local group is idle or completely loaded
3279 * no need to do power savings balance at this domain
3281 if (local_group
&& (this_nr_running
>= group_capacity
||
3283 power_savings_balance
= 0;
3286 * If a group is already running at full capacity or idle,
3287 * don't include that group in power savings calculations
3289 if (!power_savings_balance
|| sum_nr_running
>= group_capacity
3294 * Calculate the group which has the least non-idle load.
3295 * This is the group from where we need to pick up the load
3298 if ((sum_nr_running
< min_nr_running
) ||
3299 (sum_nr_running
== min_nr_running
&&
3300 cpumask_first(sched_group_cpus(group
)) >
3301 cpumask_first(sched_group_cpus(group_min
)))) {
3303 min_nr_running
= sum_nr_running
;
3304 min_load_per_task
= sum_weighted_load
/
3309 * Calculate the group which is almost near its
3310 * capacity but still has some space to pick up some load
3311 * from other group and save more power
3313 if (sum_nr_running
<= group_capacity
- 1) {
3314 if (sum_nr_running
> leader_nr_running
||
3315 (sum_nr_running
== leader_nr_running
&&
3316 cpumask_first(sched_group_cpus(group
)) <
3317 cpumask_first(sched_group_cpus(group_leader
)))) {
3318 group_leader
= group
;
3319 leader_nr_running
= sum_nr_running
;
3324 group
= group
->next
;
3325 } while (group
!= sd
->groups
);
3327 if (!busiest
|| this_load
>= max_load
|| busiest_nr_running
== 0)
3330 avg_load
= (SCHED_LOAD_SCALE
* total_load
) / total_pwr
;
3332 if (this_load
>= avg_load
||
3333 100*max_load
<= sd
->imbalance_pct
*this_load
)
3336 busiest_load_per_task
/= busiest_nr_running
;
3338 busiest_load_per_task
= min(busiest_load_per_task
, avg_load
);
3341 * We're trying to get all the cpus to the average_load, so we don't
3342 * want to push ourselves above the average load, nor do we wish to
3343 * reduce the max loaded cpu below the average load, as either of these
3344 * actions would just result in more rebalancing later, and ping-pong
3345 * tasks around. Thus we look for the minimum possible imbalance.
3346 * Negative imbalances (*we* are more loaded than anyone else) will
3347 * be counted as no imbalance for these purposes -- we can't fix that
3348 * by pulling tasks to us. Be careful of negative numbers as they'll
3349 * appear as very large values with unsigned longs.
3351 if (max_load
<= busiest_load_per_task
)
3355 * In the presence of smp nice balancing, certain scenarios can have
3356 * max load less than avg load(as we skip the groups at or below
3357 * its cpu_power, while calculating max_load..)
3359 if (max_load
< avg_load
) {
3361 goto small_imbalance
;
3364 /* Don't want to pull so many tasks that a group would go idle */
3365 max_pull
= min(max_load
- avg_load
, max_load
- busiest_load_per_task
);
3367 /* How much load to actually move to equalise the imbalance */
3368 *imbalance
= min(max_pull
* busiest
->__cpu_power
,
3369 (avg_load
- this_load
) * this->__cpu_power
)
3373 * if *imbalance is less than the average load per runnable task
3374 * there is no gaurantee that any tasks will be moved so we'll have
3375 * a think about bumping its value to force at least one task to be
3378 if (*imbalance
< busiest_load_per_task
) {
3379 unsigned long tmp
, pwr_now
, pwr_move
;
3383 pwr_move
= pwr_now
= 0;
3385 if (this_nr_running
) {
3386 this_load_per_task
/= this_nr_running
;
3387 if (busiest_load_per_task
> this_load_per_task
)
3390 this_load_per_task
= cpu_avg_load_per_task(this_cpu
);
3392 if (max_load
- this_load
+ busiest_load_per_task
>=
3393 busiest_load_per_task
* imbn
) {
3394 *imbalance
= busiest_load_per_task
;
3399 * OK, we don't have enough imbalance to justify moving tasks,
3400 * however we may be able to increase total CPU power used by
3404 pwr_now
+= busiest
->__cpu_power
*
3405 min(busiest_load_per_task
, max_load
);
3406 pwr_now
+= this->__cpu_power
*
3407 min(this_load_per_task
, this_load
);
3408 pwr_now
/= SCHED_LOAD_SCALE
;
3410 /* Amount of load we'd subtract */
3411 tmp
= sg_div_cpu_power(busiest
,
3412 busiest_load_per_task
* SCHED_LOAD_SCALE
);
3414 pwr_move
+= busiest
->__cpu_power
*
3415 min(busiest_load_per_task
, max_load
- tmp
);
3417 /* Amount of load we'd add */
3418 if (max_load
* busiest
->__cpu_power
<
3419 busiest_load_per_task
* SCHED_LOAD_SCALE
)
3420 tmp
= sg_div_cpu_power(this,
3421 max_load
* busiest
->__cpu_power
);
3423 tmp
= sg_div_cpu_power(this,
3424 busiest_load_per_task
* SCHED_LOAD_SCALE
);
3425 pwr_move
+= this->__cpu_power
*
3426 min(this_load_per_task
, this_load
+ tmp
);
3427 pwr_move
/= SCHED_LOAD_SCALE
;
3429 /* Move if we gain throughput */
3430 if (pwr_move
> pwr_now
)
3431 *imbalance
= busiest_load_per_task
;
3437 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3438 if (idle
== CPU_NOT_IDLE
|| !(sd
->flags
& SD_POWERSAVINGS_BALANCE
))
3441 if (this == group_leader
&& group_leader
!= group_min
) {
3442 *imbalance
= min_load_per_task
;
3443 if (sched_mc_power_savings
>= POWERSAVINGS_BALANCE_WAKEUP
) {
3444 cpu_rq(this_cpu
)->rd
->sched_mc_preferred_wakeup_cpu
=
3445 cpumask_first(sched_group_cpus(group_leader
));
3456 * find_busiest_queue - find the busiest runqueue among the cpus in group.
3459 find_busiest_queue(struct sched_group
*group
, enum cpu_idle_type idle
,
3460 unsigned long imbalance
, const struct cpumask
*cpus
)
3462 struct rq
*busiest
= NULL
, *rq
;
3463 unsigned long max_load
= 0;
3466 for_each_cpu(i
, sched_group_cpus(group
)) {
3469 if (!cpumask_test_cpu(i
, cpus
))
3473 wl
= weighted_cpuload(i
);
3475 if (rq
->nr_running
== 1 && wl
> imbalance
)
3478 if (wl
> max_load
) {
3488 * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but
3489 * so long as it is large enough.
3491 #define MAX_PINNED_INTERVAL 512
3494 * Check this_cpu to ensure it is balanced within domain. Attempt to move
3495 * tasks if there is an imbalance.
3497 static int load_balance(int this_cpu
, struct rq
*this_rq
,
3498 struct sched_domain
*sd
, enum cpu_idle_type idle
,
3499 int *balance
, struct cpumask
*cpus
)
3501 int ld_moved
, all_pinned
= 0, active_balance
= 0, sd_idle
= 0;
3502 struct sched_group
*group
;
3503 unsigned long imbalance
;
3505 unsigned long flags
;
3507 cpumask_setall(cpus
);
3510 * When power savings policy is enabled for the parent domain, idle
3511 * sibling can pick up load irrespective of busy siblings. In this case,
3512 * let the state of idle sibling percolate up as CPU_IDLE, instead of
3513 * portraying it as CPU_NOT_IDLE.
3515 if (idle
!= CPU_NOT_IDLE
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3516 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3519 schedstat_inc(sd
, lb_count
[idle
]);
3523 group
= find_busiest_group(sd
, this_cpu
, &imbalance
, idle
, &sd_idle
,
3530 schedstat_inc(sd
, lb_nobusyg
[idle
]);
3534 busiest
= find_busiest_queue(group
, idle
, imbalance
, cpus
);
3536 schedstat_inc(sd
, lb_nobusyq
[idle
]);
3540 BUG_ON(busiest
== this_rq
);
3542 schedstat_add(sd
, lb_imbalance
[idle
], imbalance
);
3545 if (busiest
->nr_running
> 1) {
3547 * Attempt to move tasks. If find_busiest_group has found
3548 * an imbalance but busiest->nr_running <= 1, the group is
3549 * still unbalanced. ld_moved simply stays zero, so it is
3550 * correctly treated as an imbalance.
3552 local_irq_save(flags
);
3553 double_rq_lock(this_rq
, busiest
);
3554 ld_moved
= move_tasks(this_rq
, this_cpu
, busiest
,
3555 imbalance
, sd
, idle
, &all_pinned
);
3556 double_rq_unlock(this_rq
, busiest
);
3557 local_irq_restore(flags
);
3560 * some other cpu did the load balance for us.
3562 if (ld_moved
&& this_cpu
!= smp_processor_id())
3563 resched_cpu(this_cpu
);
3565 /* All tasks on this runqueue were pinned by CPU affinity */
3566 if (unlikely(all_pinned
)) {
3567 cpumask_clear_cpu(cpu_of(busiest
), cpus
);
3568 if (!cpumask_empty(cpus
))
3575 schedstat_inc(sd
, lb_failed
[idle
]);
3576 sd
->nr_balance_failed
++;
3578 if (unlikely(sd
->nr_balance_failed
> sd
->cache_nice_tries
+2)) {
3580 spin_lock_irqsave(&busiest
->lock
, flags
);
3582 /* don't kick the migration_thread, if the curr
3583 * task on busiest cpu can't be moved to this_cpu
3585 if (!cpumask_test_cpu(this_cpu
,
3586 &busiest
->curr
->cpus_allowed
)) {
3587 spin_unlock_irqrestore(&busiest
->lock
, flags
);
3589 goto out_one_pinned
;
3592 if (!busiest
->active_balance
) {
3593 busiest
->active_balance
= 1;
3594 busiest
->push_cpu
= this_cpu
;
3597 spin_unlock_irqrestore(&busiest
->lock
, flags
);
3599 wake_up_process(busiest
->migration_thread
);
3602 * We've kicked active balancing, reset the failure
3605 sd
->nr_balance_failed
= sd
->cache_nice_tries
+1;
3608 sd
->nr_balance_failed
= 0;
3610 if (likely(!active_balance
)) {
3611 /* We were unbalanced, so reset the balancing interval */
3612 sd
->balance_interval
= sd
->min_interval
;
3615 * If we've begun active balancing, start to back off. This
3616 * case may not be covered by the all_pinned logic if there
3617 * is only 1 task on the busy runqueue (because we don't call
3620 if (sd
->balance_interval
< sd
->max_interval
)
3621 sd
->balance_interval
*= 2;
3624 if (!ld_moved
&& !sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3625 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3631 schedstat_inc(sd
, lb_balanced
[idle
]);
3633 sd
->nr_balance_failed
= 0;
3636 /* tune up the balancing interval */
3637 if ((all_pinned
&& sd
->balance_interval
< MAX_PINNED_INTERVAL
) ||
3638 (sd
->balance_interval
< sd
->max_interval
))
3639 sd
->balance_interval
*= 2;
3641 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3642 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3653 * Check this_cpu to ensure it is balanced within domain. Attempt to move
3654 * tasks if there is an imbalance.
3656 * Called from schedule when this_rq is about to become idle (CPU_NEWLY_IDLE).
3657 * this_rq is locked.
3660 load_balance_newidle(int this_cpu
, struct rq
*this_rq
, struct sched_domain
*sd
,
3661 struct cpumask
*cpus
)
3663 struct sched_group
*group
;
3664 struct rq
*busiest
= NULL
;
3665 unsigned long imbalance
;
3670 cpumask_setall(cpus
);
3673 * When power savings policy is enabled for the parent domain, idle
3674 * sibling can pick up load irrespective of busy siblings. In this case,
3675 * let the state of idle sibling percolate up as IDLE, instead of
3676 * portraying it as CPU_NOT_IDLE.
3678 if (sd
->flags
& SD_SHARE_CPUPOWER
&&
3679 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3682 schedstat_inc(sd
, lb_count
[CPU_NEWLY_IDLE
]);
3684 update_shares_locked(this_rq
, sd
);
3685 group
= find_busiest_group(sd
, this_cpu
, &imbalance
, CPU_NEWLY_IDLE
,
3686 &sd_idle
, cpus
, NULL
);
3688 schedstat_inc(sd
, lb_nobusyg
[CPU_NEWLY_IDLE
]);
3692 busiest
= find_busiest_queue(group
, CPU_NEWLY_IDLE
, imbalance
, cpus
);
3694 schedstat_inc(sd
, lb_nobusyq
[CPU_NEWLY_IDLE
]);
3698 BUG_ON(busiest
== this_rq
);
3700 schedstat_add(sd
, lb_imbalance
[CPU_NEWLY_IDLE
], imbalance
);
3703 if (busiest
->nr_running
> 1) {
3704 /* Attempt to move tasks */
3705 double_lock_balance(this_rq
, busiest
);
3706 /* this_rq->clock is already updated */
3707 update_rq_clock(busiest
);
3708 ld_moved
= move_tasks(this_rq
, this_cpu
, busiest
,
3709 imbalance
, sd
, CPU_NEWLY_IDLE
,
3711 double_unlock_balance(this_rq
, busiest
);
3713 if (unlikely(all_pinned
)) {
3714 cpumask_clear_cpu(cpu_of(busiest
), cpus
);
3715 if (!cpumask_empty(cpus
))
3721 int active_balance
= 0;
3723 schedstat_inc(sd
, lb_failed
[CPU_NEWLY_IDLE
]);
3724 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3725 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3728 if (sched_mc_power_savings
< POWERSAVINGS_BALANCE_WAKEUP
)
3731 if (sd
->nr_balance_failed
++ < 2)
3735 * The only task running in a non-idle cpu can be moved to this
3736 * cpu in an attempt to completely freeup the other CPU
3737 * package. The same method used to move task in load_balance()
3738 * have been extended for load_balance_newidle() to speedup
3739 * consolidation at sched_mc=POWERSAVINGS_BALANCE_WAKEUP (2)
3741 * The package power saving logic comes from
3742 * find_busiest_group(). If there are no imbalance, then
3743 * f_b_g() will return NULL. However when sched_mc={1,2} then
3744 * f_b_g() will select a group from which a running task may be
3745 * pulled to this cpu in order to make the other package idle.
3746 * If there is no opportunity to make a package idle and if
3747 * there are no imbalance, then f_b_g() will return NULL and no
3748 * action will be taken in load_balance_newidle().
3750 * Under normal task pull operation due to imbalance, there
3751 * will be more than one task in the source run queue and
3752 * move_tasks() will succeed. ld_moved will be true and this
3753 * active balance code will not be triggered.
3756 /* Lock busiest in correct order while this_rq is held */
3757 double_lock_balance(this_rq
, busiest
);
3760 * don't kick the migration_thread, if the curr
3761 * task on busiest cpu can't be moved to this_cpu
3763 if (!cpumask_test_cpu(this_cpu
, &busiest
->curr
->cpus_allowed
)) {
3764 double_unlock_balance(this_rq
, busiest
);
3769 if (!busiest
->active_balance
) {
3770 busiest
->active_balance
= 1;
3771 busiest
->push_cpu
= this_cpu
;
3775 double_unlock_balance(this_rq
, busiest
);
3777 * Should not call ttwu while holding a rq->lock
3779 spin_unlock(&this_rq
->lock
);
3781 wake_up_process(busiest
->migration_thread
);
3782 spin_lock(&this_rq
->lock
);
3785 sd
->nr_balance_failed
= 0;
3787 update_shares_locked(this_rq
, sd
);
3791 schedstat_inc(sd
, lb_balanced
[CPU_NEWLY_IDLE
]);
3792 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3793 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3795 sd
->nr_balance_failed
= 0;
3801 * idle_balance is called by schedule() if this_cpu is about to become
3802 * idle. Attempts to pull tasks from other CPUs.
3804 static void idle_balance(int this_cpu
, struct rq
*this_rq
)
3806 struct sched_domain
*sd
;
3807 int pulled_task
= 0;
3808 unsigned long next_balance
= jiffies
+ HZ
;
3809 cpumask_var_t tmpmask
;
3811 if (!alloc_cpumask_var(&tmpmask
, GFP_ATOMIC
))
3814 for_each_domain(this_cpu
, sd
) {
3815 unsigned long interval
;
3817 if (!(sd
->flags
& SD_LOAD_BALANCE
))
3820 if (sd
->flags
& SD_BALANCE_NEWIDLE
)
3821 /* If we've pulled tasks over stop searching: */
3822 pulled_task
= load_balance_newidle(this_cpu
, this_rq
,
3825 interval
= msecs_to_jiffies(sd
->balance_interval
);
3826 if (time_after(next_balance
, sd
->last_balance
+ interval
))
3827 next_balance
= sd
->last_balance
+ interval
;
3831 if (pulled_task
|| time_after(jiffies
, this_rq
->next_balance
)) {
3833 * We are going idle. next_balance may be set based on
3834 * a busy processor. So reset next_balance.
3836 this_rq
->next_balance
= next_balance
;
3838 free_cpumask_var(tmpmask
);
3842 * active_load_balance is run by migration threads. It pushes running tasks
3843 * off the busiest CPU onto idle CPUs. It requires at least 1 task to be
3844 * running on each physical CPU where possible, and avoids physical /
3845 * logical imbalances.
3847 * Called with busiest_rq locked.
3849 static void active_load_balance(struct rq
*busiest_rq
, int busiest_cpu
)
3851 int target_cpu
= busiest_rq
->push_cpu
;
3852 struct sched_domain
*sd
;
3853 struct rq
*target_rq
;
3855 /* Is there any task to move? */
3856 if (busiest_rq
->nr_running
<= 1)
3859 target_rq
= cpu_rq(target_cpu
);
3862 * This condition is "impossible", if it occurs
3863 * we need to fix it. Originally reported by
3864 * Bjorn Helgaas on a 128-cpu setup.
3866 BUG_ON(busiest_rq
== target_rq
);
3868 /* move a task from busiest_rq to target_rq */
3869 double_lock_balance(busiest_rq
, target_rq
);
3870 update_rq_clock(busiest_rq
);
3871 update_rq_clock(target_rq
);
3873 /* Search for an sd spanning us and the target CPU. */
3874 for_each_domain(target_cpu
, sd
) {
3875 if ((sd
->flags
& SD_LOAD_BALANCE
) &&
3876 cpumask_test_cpu(busiest_cpu
, sched_domain_span(sd
)))
3881 schedstat_inc(sd
, alb_count
);
3883 if (move_one_task(target_rq
, target_cpu
, busiest_rq
,
3885 schedstat_inc(sd
, alb_pushed
);
3887 schedstat_inc(sd
, alb_failed
);
3889 double_unlock_balance(busiest_rq
, target_rq
);
3894 atomic_t load_balancer
;
3895 cpumask_var_t cpu_mask
;
3896 } nohz ____cacheline_aligned
= {
3897 .load_balancer
= ATOMIC_INIT(-1),
3901 * This routine will try to nominate the ilb (idle load balancing)
3902 * owner among the cpus whose ticks are stopped. ilb owner will do the idle
3903 * load balancing on behalf of all those cpus. If all the cpus in the system
3904 * go into this tickless mode, then there will be no ilb owner (as there is
3905 * no need for one) and all the cpus will sleep till the next wakeup event
3908 * For the ilb owner, tick is not stopped. And this tick will be used
3909 * for idle load balancing. ilb owner will still be part of
3912 * While stopping the tick, this cpu will become the ilb owner if there
3913 * is no other owner. And will be the owner till that cpu becomes busy
3914 * or if all cpus in the system stop their ticks at which point
3915 * there is no need for ilb owner.
3917 * When the ilb owner becomes busy, it nominates another owner, during the
3918 * next busy scheduler_tick()
3920 int select_nohz_load_balancer(int stop_tick
)
3922 int cpu
= smp_processor_id();
3925 cpumask_set_cpu(cpu
, nohz
.cpu_mask
);
3926 cpu_rq(cpu
)->in_nohz_recently
= 1;
3929 * If we are going offline and still the leader, give up!
3931 if (!cpu_active(cpu
) &&
3932 atomic_read(&nohz
.load_balancer
) == cpu
) {
3933 if (atomic_cmpxchg(&nohz
.load_balancer
, cpu
, -1) != cpu
)
3938 /* time for ilb owner also to sleep */
3939 if (cpumask_weight(nohz
.cpu_mask
) == num_online_cpus()) {
3940 if (atomic_read(&nohz
.load_balancer
) == cpu
)
3941 atomic_set(&nohz
.load_balancer
, -1);
3945 if (atomic_read(&nohz
.load_balancer
) == -1) {
3946 /* make me the ilb owner */
3947 if (atomic_cmpxchg(&nohz
.load_balancer
, -1, cpu
) == -1)
3949 } else if (atomic_read(&nohz
.load_balancer
) == cpu
)
3952 if (!cpumask_test_cpu(cpu
, nohz
.cpu_mask
))
3955 cpumask_clear_cpu(cpu
, nohz
.cpu_mask
);
3957 if (atomic_read(&nohz
.load_balancer
) == cpu
)
3958 if (atomic_cmpxchg(&nohz
.load_balancer
, cpu
, -1) != cpu
)
3965 static DEFINE_SPINLOCK(balancing
);
3968 * It checks each scheduling domain to see if it is due to be balanced,
3969 * and initiates a balancing operation if so.
3971 * Balancing parameters are set up in arch_init_sched_domains.
3973 static void rebalance_domains(int cpu
, enum cpu_idle_type idle
)
3976 struct rq
*rq
= cpu_rq(cpu
);
3977 unsigned long interval
;
3978 struct sched_domain
*sd
;
3979 /* Earliest time when we have to do rebalance again */
3980 unsigned long next_balance
= jiffies
+ 60*HZ
;
3981 int update_next_balance
= 0;
3985 /* Fails alloc? Rebalancing probably not a priority right now. */
3986 if (!alloc_cpumask_var(&tmp
, GFP_ATOMIC
))
3989 for_each_domain(cpu
, sd
) {
3990 if (!(sd
->flags
& SD_LOAD_BALANCE
))
3993 interval
= sd
->balance_interval
;
3994 if (idle
!= CPU_IDLE
)
3995 interval
*= sd
->busy_factor
;
3997 /* scale ms to jiffies */
3998 interval
= msecs_to_jiffies(interval
);
3999 if (unlikely(!interval
))
4001 if (interval
> HZ
*NR_CPUS
/10)
4002 interval
= HZ
*NR_CPUS
/10;
4004 need_serialize
= sd
->flags
& SD_SERIALIZE
;
4006 if (need_serialize
) {
4007 if (!spin_trylock(&balancing
))
4011 if (time_after_eq(jiffies
, sd
->last_balance
+ interval
)) {
4012 if (load_balance(cpu
, rq
, sd
, idle
, &balance
, tmp
)) {
4014 * We've pulled tasks over so either we're no
4015 * longer idle, or one of our SMT siblings is
4018 idle
= CPU_NOT_IDLE
;
4020 sd
->last_balance
= jiffies
;
4023 spin_unlock(&balancing
);
4025 if (time_after(next_balance
, sd
->last_balance
+ interval
)) {
4026 next_balance
= sd
->last_balance
+ interval
;
4027 update_next_balance
= 1;
4031 * Stop the load balance at this level. There is another
4032 * CPU in our sched group which is doing load balancing more
4040 * next_balance will be updated only when there is a need.
4041 * When the cpu is attached to null domain for ex, it will not be
4044 if (likely(update_next_balance
))
4045 rq
->next_balance
= next_balance
;
4047 free_cpumask_var(tmp
);
4051 * run_rebalance_domains is triggered when needed from the scheduler tick.
4052 * In CONFIG_NO_HZ case, the idle load balance owner will do the
4053 * rebalancing for all the cpus for whom scheduler ticks are stopped.
4055 static void run_rebalance_domains(struct softirq_action
*h
)
4057 int this_cpu
= smp_processor_id();
4058 struct rq
*this_rq
= cpu_rq(this_cpu
);
4059 enum cpu_idle_type idle
= this_rq
->idle_at_tick
?
4060 CPU_IDLE
: CPU_NOT_IDLE
;
4062 rebalance_domains(this_cpu
, idle
);
4066 * If this cpu is the owner for idle load balancing, then do the
4067 * balancing on behalf of the other idle cpus whose ticks are
4070 if (this_rq
->idle_at_tick
&&
4071 atomic_read(&nohz
.load_balancer
) == this_cpu
) {
4075 for_each_cpu(balance_cpu
, nohz
.cpu_mask
) {
4076 if (balance_cpu
== this_cpu
)
4080 * If this cpu gets work to do, stop the load balancing
4081 * work being done for other cpus. Next load
4082 * balancing owner will pick it up.
4087 rebalance_domains(balance_cpu
, CPU_IDLE
);
4089 rq
= cpu_rq(balance_cpu
);
4090 if (time_after(this_rq
->next_balance
, rq
->next_balance
))
4091 this_rq
->next_balance
= rq
->next_balance
;
4098 * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing.
4100 * In case of CONFIG_NO_HZ, this is the place where we nominate a new
4101 * idle load balancing owner or decide to stop the periodic load balancing,
4102 * if the whole system is idle.
4104 static inline void trigger_load_balance(struct rq
*rq
, int cpu
)
4108 * If we were in the nohz mode recently and busy at the current
4109 * scheduler tick, then check if we need to nominate new idle
4112 if (rq
->in_nohz_recently
&& !rq
->idle_at_tick
) {
4113 rq
->in_nohz_recently
= 0;
4115 if (atomic_read(&nohz
.load_balancer
) == cpu
) {
4116 cpumask_clear_cpu(cpu
, nohz
.cpu_mask
);
4117 atomic_set(&nohz
.load_balancer
, -1);
4120 if (atomic_read(&nohz
.load_balancer
) == -1) {
4122 * simple selection for now: Nominate the
4123 * first cpu in the nohz list to be the next
4126 * TBD: Traverse the sched domains and nominate
4127 * the nearest cpu in the nohz.cpu_mask.
4129 int ilb
= cpumask_first(nohz
.cpu_mask
);
4131 if (ilb
< nr_cpu_ids
)
4137 * If this cpu is idle and doing idle load balancing for all the
4138 * cpus with ticks stopped, is it time for that to stop?
4140 if (rq
->idle_at_tick
&& atomic_read(&nohz
.load_balancer
) == cpu
&&
4141 cpumask_weight(nohz
.cpu_mask
) == num_online_cpus()) {
4147 * If this cpu is idle and the idle load balancing is done by
4148 * someone else, then no need raise the SCHED_SOFTIRQ
4150 if (rq
->idle_at_tick
&& atomic_read(&nohz
.load_balancer
) != cpu
&&
4151 cpumask_test_cpu(cpu
, nohz
.cpu_mask
))
4154 if (time_after_eq(jiffies
, rq
->next_balance
))
4155 raise_softirq(SCHED_SOFTIRQ
);
4158 #else /* CONFIG_SMP */
4161 * on UP we do not need to balance between CPUs:
4163 static inline void idle_balance(int cpu
, struct rq
*rq
)
4169 DEFINE_PER_CPU(struct kernel_stat
, kstat
);
4171 EXPORT_PER_CPU_SYMBOL(kstat
);
4174 * Return any ns on the sched_clock that have not yet been banked in
4175 * @p in case that task is currently running.
4177 unsigned long long __task_delta_exec(struct task_struct
*p
, int update
)
4183 WARN_ON_ONCE(!runqueue_is_locked());
4184 WARN_ON_ONCE(!task_current(rq
, p
));
4187 update_rq_clock(rq
);
4189 delta_exec
= rq
->clock
- p
->se
.exec_start
;
4191 WARN_ON_ONCE(delta_exec
< 0);
4197 * Return any ns on the sched_clock that have not yet been banked in
4198 * @p in case that task is currently running.
4200 unsigned long long task_delta_exec(struct task_struct
*p
)
4202 unsigned long flags
;
4206 rq
= task_rq_lock(p
, &flags
);
4208 if (task_current(rq
, p
)) {
4211 update_rq_clock(rq
);
4212 delta_exec
= rq
->clock
- p
->se
.exec_start
;
4213 if ((s64
)delta_exec
> 0)
4217 task_rq_unlock(rq
, &flags
);
4223 * Account user cpu time to a process.
4224 * @p: the process that the cpu time gets accounted to
4225 * @cputime: the cpu time spent in user space since the last update
4226 * @cputime_scaled: cputime scaled by cpu frequency
4228 void account_user_time(struct task_struct
*p
, cputime_t cputime
,
4229 cputime_t cputime_scaled
)
4231 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
4234 /* Add user time to process. */
4235 p
->utime
= cputime_add(p
->utime
, cputime
);
4236 p
->utimescaled
= cputime_add(p
->utimescaled
, cputime_scaled
);
4237 account_group_user_time(p
, cputime
);
4239 /* Add user time to cpustat. */
4240 tmp
= cputime_to_cputime64(cputime
);
4241 if (TASK_NICE(p
) > 0)
4242 cpustat
->nice
= cputime64_add(cpustat
->nice
, tmp
);
4244 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
4245 /* Account for user time used */
4246 acct_update_integrals(p
);
4250 * Account guest cpu time to a process.
4251 * @p: the process that the cpu time gets accounted to
4252 * @cputime: the cpu time spent in virtual machine since the last update
4253 * @cputime_scaled: cputime scaled by cpu frequency
4255 static void account_guest_time(struct task_struct
*p
, cputime_t cputime
,
4256 cputime_t cputime_scaled
)
4259 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
4261 tmp
= cputime_to_cputime64(cputime
);
4263 /* Add guest time to process. */
4264 p
->utime
= cputime_add(p
->utime
, cputime
);
4265 p
->utimescaled
= cputime_add(p
->utimescaled
, cputime_scaled
);
4266 account_group_user_time(p
, cputime
);
4267 p
->gtime
= cputime_add(p
->gtime
, cputime
);
4269 /* Add guest time to cpustat. */
4270 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
4271 cpustat
->guest
= cputime64_add(cpustat
->guest
, tmp
);
4275 * Account system cpu time to a process.
4276 * @p: the process that the cpu time gets accounted to
4277 * @hardirq_offset: the offset to subtract from hardirq_count()
4278 * @cputime: the cpu time spent in kernel space since the last update
4279 * @cputime_scaled: cputime scaled by cpu frequency
4281 void account_system_time(struct task_struct
*p
, int hardirq_offset
,
4282 cputime_t cputime
, cputime_t cputime_scaled
)
4284 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
4287 if ((p
->flags
& PF_VCPU
) && (irq_count() - hardirq_offset
== 0)) {
4288 account_guest_time(p
, cputime
, cputime_scaled
);
4292 /* Add system time to process. */
4293 p
->stime
= cputime_add(p
->stime
, cputime
);
4294 p
->stimescaled
= cputime_add(p
->stimescaled
, cputime_scaled
);
4295 account_group_system_time(p
, cputime
);
4297 /* Add system time to cpustat. */
4298 tmp
= cputime_to_cputime64(cputime
);
4299 if (hardirq_count() - hardirq_offset
)
4300 cpustat
->irq
= cputime64_add(cpustat
->irq
, tmp
);
4301 else if (softirq_count())
4302 cpustat
->softirq
= cputime64_add(cpustat
->softirq
, tmp
);
4304 cpustat
->system
= cputime64_add(cpustat
->system
, tmp
);
4306 /* Account for system time used */
4307 acct_update_integrals(p
);
4311 * Account for involuntary wait time.
4312 * @steal: the cpu time spent in involuntary wait
4314 void account_steal_time(cputime_t cputime
)
4316 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
4317 cputime64_t cputime64
= cputime_to_cputime64(cputime
);
4319 cpustat
->steal
= cputime64_add(cpustat
->steal
, cputime64
);
4323 * Account for idle time.
4324 * @cputime: the cpu time spent in idle wait
4326 void account_idle_time(cputime_t cputime
)
4328 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
4329 cputime64_t cputime64
= cputime_to_cputime64(cputime
);
4330 struct rq
*rq
= this_rq();
4332 if (atomic_read(&rq
->nr_iowait
) > 0)
4333 cpustat
->iowait
= cputime64_add(cpustat
->iowait
, cputime64
);
4335 cpustat
->idle
= cputime64_add(cpustat
->idle
, cputime64
);
4338 #ifndef CONFIG_VIRT_CPU_ACCOUNTING
4341 * Account a single tick of cpu time.
4342 * @p: the process that the cpu time gets accounted to
4343 * @user_tick: indicates if the tick is a user or a system tick
4345 void account_process_tick(struct task_struct
*p
, int user_tick
)
4347 cputime_t one_jiffy
= jiffies_to_cputime(1);
4348 cputime_t one_jiffy_scaled
= cputime_to_scaled(one_jiffy
);
4349 struct rq
*rq
= this_rq();
4352 account_user_time(p
, one_jiffy
, one_jiffy_scaled
);
4353 else if (p
!= rq
->idle
)
4354 account_system_time(p
, HARDIRQ_OFFSET
, one_jiffy
,
4357 account_idle_time(one_jiffy
);
4361 * Account multiple ticks of steal time.
4362 * @p: the process from which the cpu time has been stolen
4363 * @ticks: number of stolen ticks
4365 void account_steal_ticks(unsigned long ticks
)
4367 account_steal_time(jiffies_to_cputime(ticks
));
4371 * Account multiple ticks of idle time.
4372 * @ticks: number of stolen ticks
4374 void account_idle_ticks(unsigned long ticks
)
4376 account_idle_time(jiffies_to_cputime(ticks
));
4382 * Use precise platform statistics if available:
4384 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
4385 cputime_t
task_utime(struct task_struct
*p
)
4390 cputime_t
task_stime(struct task_struct
*p
)
4395 cputime_t
task_utime(struct task_struct
*p
)
4397 clock_t utime
= cputime_to_clock_t(p
->utime
),
4398 total
= utime
+ cputime_to_clock_t(p
->stime
);
4402 * Use CFS's precise accounting:
4404 temp
= (u64
)nsec_to_clock_t(p
->se
.sum_exec_runtime
);
4408 do_div(temp
, total
);
4410 utime
= (clock_t)temp
;
4412 p
->prev_utime
= max(p
->prev_utime
, clock_t_to_cputime(utime
));
4413 return p
->prev_utime
;
4416 cputime_t
task_stime(struct task_struct
*p
)
4421 * Use CFS's precise accounting. (we subtract utime from
4422 * the total, to make sure the total observed by userspace
4423 * grows monotonically - apps rely on that):
4425 stime
= nsec_to_clock_t(p
->se
.sum_exec_runtime
) -
4426 cputime_to_clock_t(task_utime(p
));
4429 p
->prev_stime
= max(p
->prev_stime
, clock_t_to_cputime(stime
));
4431 return p
->prev_stime
;
4435 inline cputime_t
task_gtime(struct task_struct
*p
)
4441 * This function gets called by the timer code, with HZ frequency.
4442 * We call it with interrupts disabled.
4444 * It also gets called by the fork code, when changing the parent's
4447 void scheduler_tick(void)
4449 int cpu
= smp_processor_id();
4450 struct rq
*rq
= cpu_rq(cpu
);
4451 struct task_struct
*curr
= rq
->curr
;
4455 spin_lock(&rq
->lock
);
4456 update_rq_clock(rq
);
4457 update_cpu_load(rq
);
4458 curr
->sched_class
->task_tick(rq
, curr
, 0);
4459 perf_counter_task_tick(curr
, cpu
);
4460 spin_unlock(&rq
->lock
);
4463 rq
->idle_at_tick
= idle_cpu(cpu
);
4464 trigger_load_balance(rq
, cpu
);
4468 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
4469 defined(CONFIG_PREEMPT_TRACER))
4471 static inline unsigned long get_parent_ip(unsigned long addr
)
4473 if (in_lock_functions(addr
)) {
4474 addr
= CALLER_ADDR2
;
4475 if (in_lock_functions(addr
))
4476 addr
= CALLER_ADDR3
;
4481 void __kprobes
add_preempt_count(int val
)
4483 #ifdef CONFIG_DEBUG_PREEMPT
4487 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
4490 preempt_count() += val
;
4491 #ifdef CONFIG_DEBUG_PREEMPT
4493 * Spinlock count overflowing soon?
4495 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK
) >=
4498 if (preempt_count() == val
)
4499 trace_preempt_off(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
4501 EXPORT_SYMBOL(add_preempt_count
);
4503 void __kprobes
sub_preempt_count(int val
)
4505 #ifdef CONFIG_DEBUG_PREEMPT
4509 if (DEBUG_LOCKS_WARN_ON(val
> preempt_count() - (!!kernel_locked())))
4512 * Is the spinlock portion underflowing?
4514 if (DEBUG_LOCKS_WARN_ON((val
< PREEMPT_MASK
) &&
4515 !(preempt_count() & PREEMPT_MASK
)))
4519 if (preempt_count() == val
)
4520 trace_preempt_on(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
4521 preempt_count() -= val
;
4523 EXPORT_SYMBOL(sub_preempt_count
);
4528 * Print scheduling while atomic bug:
4530 static noinline
void __schedule_bug(struct task_struct
*prev
)
4532 struct pt_regs
*regs
= get_irq_regs();
4534 printk(KERN_ERR
"BUG: scheduling while atomic: %s/%d/0x%08x\n",
4535 prev
->comm
, prev
->pid
, preempt_count());
4537 debug_show_held_locks(prev
);
4539 if (irqs_disabled())
4540 print_irqtrace_events(prev
);
4549 * Various schedule()-time debugging checks and statistics:
4551 static inline void schedule_debug(struct task_struct
*prev
)
4554 * Test if we are atomic. Since do_exit() needs to call into
4555 * schedule() atomically, we ignore that path for now.
4556 * Otherwise, whine if we are scheduling when we should not be.
4558 if (unlikely(in_atomic_preempt_off() && !prev
->exit_state
))
4559 __schedule_bug(prev
);
4561 profile_hit(SCHED_PROFILING
, __builtin_return_address(0));
4563 schedstat_inc(this_rq(), sched_count
);
4564 #ifdef CONFIG_SCHEDSTATS
4565 if (unlikely(prev
->lock_depth
>= 0)) {
4566 schedstat_inc(this_rq(), bkl_count
);
4567 schedstat_inc(prev
, sched_info
.bkl_count
);
4573 * Pick up the highest-prio task:
4575 static inline struct task_struct
*
4576 pick_next_task(struct rq
*rq
, struct task_struct
*prev
)
4578 const struct sched_class
*class;
4579 struct task_struct
*p
;
4582 * Optimization: we know that if all tasks are in
4583 * the fair class we can call that function directly:
4585 if (likely(rq
->nr_running
== rq
->cfs
.nr_running
)) {
4586 p
= fair_sched_class
.pick_next_task(rq
);
4591 class = sched_class_highest
;
4593 p
= class->pick_next_task(rq
);
4597 * Will never be NULL as the idle class always
4598 * returns a non-NULL p:
4600 class = class->next
;
4605 * schedule() is the main scheduler function.
4607 asmlinkage
void __sched
schedule(void)
4609 struct task_struct
*prev
, *next
;
4610 unsigned long *switch_count
;
4616 cpu
= smp_processor_id();
4620 switch_count
= &prev
->nivcsw
;
4622 release_kernel_lock(prev
);
4623 need_resched_nonpreemptible
:
4625 schedule_debug(prev
);
4627 if (sched_feat(HRTICK
))
4630 spin_lock_irq(&rq
->lock
);
4631 update_rq_clock(rq
);
4632 clear_tsk_need_resched(prev
);
4634 if (prev
->state
&& !(preempt_count() & PREEMPT_ACTIVE
)) {
4635 if (unlikely(signal_pending_state(prev
->state
, prev
)))
4636 prev
->state
= TASK_RUNNING
;
4638 deactivate_task(rq
, prev
, 1);
4639 switch_count
= &prev
->nvcsw
;
4643 if (prev
->sched_class
->pre_schedule
)
4644 prev
->sched_class
->pre_schedule(rq
, prev
);
4647 if (unlikely(!rq
->nr_running
))
4648 idle_balance(cpu
, rq
);
4650 prev
->sched_class
->put_prev_task(rq
, prev
);
4651 next
= pick_next_task(rq
, prev
);
4653 if (likely(prev
!= next
)) {
4654 sched_info_switch(prev
, next
);
4655 perf_counter_task_sched_out(prev
, cpu
);
4661 context_switch(rq
, prev
, next
); /* unlocks the rq */
4663 * the context switch might have flipped the stack from under
4664 * us, hence refresh the local variables.
4666 cpu
= smp_processor_id();
4669 spin_unlock_irq(&rq
->lock
);
4671 if (unlikely(reacquire_kernel_lock(current
) < 0))
4672 goto need_resched_nonpreemptible
;
4674 preempt_enable_no_resched();
4675 if (unlikely(test_thread_flag(TIF_NEED_RESCHED
)))
4678 EXPORT_SYMBOL(schedule
);
4680 #ifdef CONFIG_PREEMPT
4682 * this is the entry point to schedule() from in-kernel preemption
4683 * off of preempt_enable. Kernel preemptions off return from interrupt
4684 * occur there and call schedule directly.
4686 asmlinkage
void __sched
preempt_schedule(void)
4688 struct thread_info
*ti
= current_thread_info();
4691 * If there is a non-zero preempt_count or interrupts are disabled,
4692 * we do not want to preempt the current task. Just return..
4694 if (likely(ti
->preempt_count
|| irqs_disabled()))
4698 add_preempt_count(PREEMPT_ACTIVE
);
4700 sub_preempt_count(PREEMPT_ACTIVE
);
4703 * Check again in case we missed a preemption opportunity
4704 * between schedule and now.
4707 } while (unlikely(test_thread_flag(TIF_NEED_RESCHED
)));
4709 EXPORT_SYMBOL(preempt_schedule
);
4712 * this is the entry point to schedule() from kernel preemption
4713 * off of irq context.
4714 * Note, that this is called and return with irqs disabled. This will
4715 * protect us against recursive calling from irq.
4717 asmlinkage
void __sched
preempt_schedule_irq(void)
4719 struct thread_info
*ti
= current_thread_info();
4721 /* Catch callers which need to be fixed */
4722 BUG_ON(ti
->preempt_count
|| !irqs_disabled());
4725 add_preempt_count(PREEMPT_ACTIVE
);
4728 local_irq_disable();
4729 sub_preempt_count(PREEMPT_ACTIVE
);
4732 * Check again in case we missed a preemption opportunity
4733 * between schedule and now.
4736 } while (unlikely(test_thread_flag(TIF_NEED_RESCHED
)));
4739 #endif /* CONFIG_PREEMPT */
4741 int default_wake_function(wait_queue_t
*curr
, unsigned mode
, int sync
,
4744 return try_to_wake_up(curr
->private, mode
, sync
);
4746 EXPORT_SYMBOL(default_wake_function
);
4749 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
4750 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
4751 * number) then we wake all the non-exclusive tasks and one exclusive task.
4753 * There are circumstances in which we can try to wake a task which has already
4754 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
4755 * zero in this (rare) case, and we handle it by continuing to scan the queue.
4757 static void __wake_up_common(wait_queue_head_t
*q
, unsigned int mode
,
4758 int nr_exclusive
, int sync
, void *key
)
4760 wait_queue_t
*curr
, *next
;
4762 list_for_each_entry_safe(curr
, next
, &q
->task_list
, task_list
) {
4763 unsigned flags
= curr
->flags
;
4765 if (curr
->func(curr
, mode
, sync
, key
) &&
4766 (flags
& WQ_FLAG_EXCLUSIVE
) && !--nr_exclusive
)
4772 * __wake_up - wake up threads blocked on a waitqueue.
4774 * @mode: which threads
4775 * @nr_exclusive: how many wake-one or wake-many threads to wake up
4776 * @key: is directly passed to the wakeup function
4778 void __wake_up(wait_queue_head_t
*q
, unsigned int mode
,
4779 int nr_exclusive
, void *key
)
4781 unsigned long flags
;
4783 spin_lock_irqsave(&q
->lock
, flags
);
4784 __wake_up_common(q
, mode
, nr_exclusive
, 0, key
);
4785 spin_unlock_irqrestore(&q
->lock
, flags
);
4787 EXPORT_SYMBOL(__wake_up
);
4790 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
4792 void __wake_up_locked(wait_queue_head_t
*q
, unsigned int mode
)
4794 __wake_up_common(q
, mode
, 1, 0, NULL
);
4798 * __wake_up_sync - wake up threads blocked on a waitqueue.
4800 * @mode: which threads
4801 * @nr_exclusive: how many wake-one or wake-many threads to wake up
4803 * The sync wakeup differs that the waker knows that it will schedule
4804 * away soon, so while the target thread will be woken up, it will not
4805 * be migrated to another CPU - ie. the two threads are 'synchronized'
4806 * with each other. This can prevent needless bouncing between CPUs.
4808 * On UP it can prevent extra preemption.
4811 __wake_up_sync(wait_queue_head_t
*q
, unsigned int mode
, int nr_exclusive
)
4813 unsigned long flags
;
4819 if (unlikely(!nr_exclusive
))
4822 spin_lock_irqsave(&q
->lock
, flags
);
4823 __wake_up_common(q
, mode
, nr_exclusive
, sync
, NULL
);
4824 spin_unlock_irqrestore(&q
->lock
, flags
);
4826 EXPORT_SYMBOL_GPL(__wake_up_sync
); /* For internal use only */
4829 * complete: - signals a single thread waiting on this completion
4830 * @x: holds the state of this particular completion
4832 * This will wake up a single thread waiting on this completion. Threads will be
4833 * awakened in the same order in which they were queued.
4835 * See also complete_all(), wait_for_completion() and related routines.
4837 void complete(struct completion
*x
)
4839 unsigned long flags
;
4841 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4843 __wake_up_common(&x
->wait
, TASK_NORMAL
, 1, 0, NULL
);
4844 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4846 EXPORT_SYMBOL(complete
);
4849 * complete_all: - signals all threads waiting on this completion
4850 * @x: holds the state of this particular completion
4852 * This will wake up all threads waiting on this particular completion event.
4854 void complete_all(struct completion
*x
)
4856 unsigned long flags
;
4858 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4859 x
->done
+= UINT_MAX
/2;
4860 __wake_up_common(&x
->wait
, TASK_NORMAL
, 0, 0, NULL
);
4861 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4863 EXPORT_SYMBOL(complete_all
);
4865 static inline long __sched
4866 do_wait_for_common(struct completion
*x
, long timeout
, int state
)
4869 DECLARE_WAITQUEUE(wait
, current
);
4871 wait
.flags
|= WQ_FLAG_EXCLUSIVE
;
4872 __add_wait_queue_tail(&x
->wait
, &wait
);
4874 if (signal_pending_state(state
, current
)) {
4875 timeout
= -ERESTARTSYS
;
4878 __set_current_state(state
);
4879 spin_unlock_irq(&x
->wait
.lock
);
4880 timeout
= schedule_timeout(timeout
);
4881 spin_lock_irq(&x
->wait
.lock
);
4882 } while (!x
->done
&& timeout
);
4883 __remove_wait_queue(&x
->wait
, &wait
);
4888 return timeout
?: 1;
4892 wait_for_common(struct completion
*x
, long timeout
, int state
)
4896 spin_lock_irq(&x
->wait
.lock
);
4897 timeout
= do_wait_for_common(x
, timeout
, state
);
4898 spin_unlock_irq(&x
->wait
.lock
);
4903 * wait_for_completion: - waits for completion of a task
4904 * @x: holds the state of this particular completion
4906 * This waits to be signaled for completion of a specific task. It is NOT
4907 * interruptible and there is no timeout.
4909 * See also similar routines (i.e. wait_for_completion_timeout()) with timeout
4910 * and interrupt capability. Also see complete().
4912 void __sched
wait_for_completion(struct completion
*x
)
4914 wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_UNINTERRUPTIBLE
);
4916 EXPORT_SYMBOL(wait_for_completion
);
4919 * wait_for_completion_timeout: - waits for completion of a task (w/timeout)
4920 * @x: holds the state of this particular completion
4921 * @timeout: timeout value in jiffies
4923 * This waits for either a completion of a specific task to be signaled or for a
4924 * specified timeout to expire. The timeout is in jiffies. It is not
4927 unsigned long __sched
4928 wait_for_completion_timeout(struct completion
*x
, unsigned long timeout
)
4930 return wait_for_common(x
, timeout
, TASK_UNINTERRUPTIBLE
);
4932 EXPORT_SYMBOL(wait_for_completion_timeout
);
4935 * wait_for_completion_interruptible: - waits for completion of a task (w/intr)
4936 * @x: holds the state of this particular completion
4938 * This waits for completion of a specific task to be signaled. It is
4941 int __sched
wait_for_completion_interruptible(struct completion
*x
)
4943 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_INTERRUPTIBLE
);
4944 if (t
== -ERESTARTSYS
)
4948 EXPORT_SYMBOL(wait_for_completion_interruptible
);
4951 * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr))
4952 * @x: holds the state of this particular completion
4953 * @timeout: timeout value in jiffies
4955 * This waits for either a completion of a specific task to be signaled or for a
4956 * specified timeout to expire. It is interruptible. The timeout is in jiffies.
4958 unsigned long __sched
4959 wait_for_completion_interruptible_timeout(struct completion
*x
,
4960 unsigned long timeout
)
4962 return wait_for_common(x
, timeout
, TASK_INTERRUPTIBLE
);
4964 EXPORT_SYMBOL(wait_for_completion_interruptible_timeout
);
4967 * wait_for_completion_killable: - waits for completion of a task (killable)
4968 * @x: holds the state of this particular completion
4970 * This waits to be signaled for completion of a specific task. It can be
4971 * interrupted by a kill signal.
4973 int __sched
wait_for_completion_killable(struct completion
*x
)
4975 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_KILLABLE
);
4976 if (t
== -ERESTARTSYS
)
4980 EXPORT_SYMBOL(wait_for_completion_killable
);
4983 * try_wait_for_completion - try to decrement a completion without blocking
4984 * @x: completion structure
4986 * Returns: 0 if a decrement cannot be done without blocking
4987 * 1 if a decrement succeeded.
4989 * If a completion is being used as a counting completion,
4990 * attempt to decrement the counter without blocking. This
4991 * enables us to avoid waiting if the resource the completion
4992 * is protecting is not available.
4994 bool try_wait_for_completion(struct completion
*x
)
4998 spin_lock_irq(&x
->wait
.lock
);
5003 spin_unlock_irq(&x
->wait
.lock
);
5006 EXPORT_SYMBOL(try_wait_for_completion
);
5009 * completion_done - Test to see if a completion has any waiters
5010 * @x: completion structure
5012 * Returns: 0 if there are waiters (wait_for_completion() in progress)
5013 * 1 if there are no waiters.
5016 bool completion_done(struct completion
*x
)
5020 spin_lock_irq(&x
->wait
.lock
);
5023 spin_unlock_irq(&x
->wait
.lock
);
5026 EXPORT_SYMBOL(completion_done
);
5029 sleep_on_common(wait_queue_head_t
*q
, int state
, long timeout
)
5031 unsigned long flags
;
5034 init_waitqueue_entry(&wait
, current
);
5036 __set_current_state(state
);
5038 spin_lock_irqsave(&q
->lock
, flags
);
5039 __add_wait_queue(q
, &wait
);
5040 spin_unlock(&q
->lock
);
5041 timeout
= schedule_timeout(timeout
);
5042 spin_lock_irq(&q
->lock
);
5043 __remove_wait_queue(q
, &wait
);
5044 spin_unlock_irqrestore(&q
->lock
, flags
);
5049 void __sched
interruptible_sleep_on(wait_queue_head_t
*q
)
5051 sleep_on_common(q
, TASK_INTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
5053 EXPORT_SYMBOL(interruptible_sleep_on
);
5056 interruptible_sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
5058 return sleep_on_common(q
, TASK_INTERRUPTIBLE
, timeout
);
5060 EXPORT_SYMBOL(interruptible_sleep_on_timeout
);
5062 void __sched
sleep_on(wait_queue_head_t
*q
)
5064 sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
5066 EXPORT_SYMBOL(sleep_on
);
5068 long __sched
sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
5070 return sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, timeout
);
5072 EXPORT_SYMBOL(sleep_on_timeout
);
5074 #ifdef CONFIG_RT_MUTEXES
5077 * rt_mutex_setprio - set the current priority of a task
5079 * @prio: prio value (kernel-internal form)
5081 * This function changes the 'effective' priority of a task. It does
5082 * not touch ->normal_prio like __setscheduler().
5084 * Used by the rt_mutex code to implement priority inheritance logic.
5086 void rt_mutex_setprio(struct task_struct
*p
, int prio
)
5088 unsigned long flags
;
5089 int oldprio
, on_rq
, running
;
5091 const struct sched_class
*prev_class
= p
->sched_class
;
5093 BUG_ON(prio
< 0 || prio
> MAX_PRIO
);
5095 rq
= task_rq_lock(p
, &flags
);
5096 update_rq_clock(rq
);
5099 on_rq
= p
->se
.on_rq
;
5100 running
= task_current(rq
, p
);
5102 dequeue_task(rq
, p
, 0);
5104 p
->sched_class
->put_prev_task(rq
, p
);
5107 p
->sched_class
= &rt_sched_class
;
5109 p
->sched_class
= &fair_sched_class
;
5114 p
->sched_class
->set_curr_task(rq
);
5116 enqueue_task(rq
, p
, 0);
5118 check_class_changed(rq
, p
, prev_class
, oldprio
, running
);
5120 task_rq_unlock(rq
, &flags
);
5125 void set_user_nice(struct task_struct
*p
, long nice
)
5127 int old_prio
, delta
, on_rq
;
5128 unsigned long flags
;
5131 if (TASK_NICE(p
) == nice
|| nice
< -20 || nice
> 19)
5134 * We have to be careful, if called from sys_setpriority(),
5135 * the task might be in the middle of scheduling on another CPU.
5137 rq
= task_rq_lock(p
, &flags
);
5138 update_rq_clock(rq
);
5140 * The RT priorities are set via sched_setscheduler(), but we still
5141 * allow the 'normal' nice value to be set - but as expected
5142 * it wont have any effect on scheduling until the task is
5143 * SCHED_FIFO/SCHED_RR:
5145 if (task_has_rt_policy(p
)) {
5146 p
->static_prio
= NICE_TO_PRIO(nice
);
5149 on_rq
= p
->se
.on_rq
;
5151 dequeue_task(rq
, p
, 0);
5153 p
->static_prio
= NICE_TO_PRIO(nice
);
5156 p
->prio
= effective_prio(p
);
5157 delta
= p
->prio
- old_prio
;
5160 enqueue_task(rq
, p
, 0);
5162 * If the task increased its priority or is running and
5163 * lowered its priority, then reschedule its CPU:
5165 if (delta
< 0 || (delta
> 0 && task_running(rq
, p
)))
5166 resched_task(rq
->curr
);
5169 task_rq_unlock(rq
, &flags
);
5171 EXPORT_SYMBOL(set_user_nice
);
5174 * can_nice - check if a task can reduce its nice value
5178 int can_nice(const struct task_struct
*p
, const int nice
)
5180 /* convert nice value [19,-20] to rlimit style value [1,40] */
5181 int nice_rlim
= 20 - nice
;
5183 return (nice_rlim
<= p
->signal
->rlim
[RLIMIT_NICE
].rlim_cur
||
5184 capable(CAP_SYS_NICE
));
5187 #ifdef __ARCH_WANT_SYS_NICE
5190 * sys_nice - change the priority of the current process.
5191 * @increment: priority increment
5193 * sys_setpriority is a more generic, but much slower function that
5194 * does similar things.
5196 asmlinkage
long sys_nice(int increment
)
5201 * Setpriority might change our priority at the same moment.
5202 * We don't have to worry. Conceptually one call occurs first
5203 * and we have a single winner.
5205 if (increment
< -40)
5210 nice
= PRIO_TO_NICE(current
->static_prio
) + increment
;
5216 if (increment
< 0 && !can_nice(current
, nice
))
5219 retval
= security_task_setnice(current
, nice
);
5223 set_user_nice(current
, nice
);
5230 * task_prio - return the priority value of a given task.
5231 * @p: the task in question.
5233 * This is the priority value as seen by users in /proc.
5234 * RT tasks are offset by -200. Normal tasks are centered
5235 * around 0, value goes from -16 to +15.
5237 int task_prio(const struct task_struct
*p
)
5239 return p
->prio
- MAX_RT_PRIO
;
5243 * task_nice - return the nice value of a given task.
5244 * @p: the task in question.
5246 int task_nice(const struct task_struct
*p
)
5248 return TASK_NICE(p
);
5250 EXPORT_SYMBOL(task_nice
);
5253 * idle_cpu - is a given cpu idle currently?
5254 * @cpu: the processor in question.
5256 int idle_cpu(int cpu
)
5258 return cpu_curr(cpu
) == cpu_rq(cpu
)->idle
;
5262 * idle_task - return the idle task for a given cpu.
5263 * @cpu: the processor in question.
5265 struct task_struct
*idle_task(int cpu
)
5267 return cpu_rq(cpu
)->idle
;
5271 * find_process_by_pid - find a process with a matching PID value.
5272 * @pid: the pid in question.
5274 static struct task_struct
*find_process_by_pid(pid_t pid
)
5276 return pid
? find_task_by_vpid(pid
) : current
;
5279 /* Actually do priority change: must hold rq lock. */
5281 __setscheduler(struct rq
*rq
, struct task_struct
*p
, int policy
, int prio
)
5283 BUG_ON(p
->se
.on_rq
);
5286 switch (p
->policy
) {
5290 p
->sched_class
= &fair_sched_class
;
5294 p
->sched_class
= &rt_sched_class
;
5298 p
->rt_priority
= prio
;
5299 p
->normal_prio
= normal_prio(p
);
5300 /* we are holding p->pi_lock already */
5301 p
->prio
= rt_mutex_getprio(p
);
5306 * check the target process has a UID that matches the current process's
5308 static bool check_same_owner(struct task_struct
*p
)
5310 const struct cred
*cred
= current_cred(), *pcred
;
5314 pcred
= __task_cred(p
);
5315 match
= (cred
->euid
== pcred
->euid
||
5316 cred
->euid
== pcred
->uid
);
5321 static int __sched_setscheduler(struct task_struct
*p
, int policy
,
5322 struct sched_param
*param
, bool user
)
5324 int retval
, oldprio
, oldpolicy
= -1, on_rq
, running
;
5325 unsigned long flags
;
5326 const struct sched_class
*prev_class
= p
->sched_class
;
5329 /* may grab non-irq protected spin_locks */
5330 BUG_ON(in_interrupt());
5332 /* double check policy once rq lock held */
5334 policy
= oldpolicy
= p
->policy
;
5335 else if (policy
!= SCHED_FIFO
&& policy
!= SCHED_RR
&&
5336 policy
!= SCHED_NORMAL
&& policy
!= SCHED_BATCH
&&
5337 policy
!= SCHED_IDLE
)
5340 * Valid priorities for SCHED_FIFO and SCHED_RR are
5341 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
5342 * SCHED_BATCH and SCHED_IDLE is 0.
5344 if (param
->sched_priority
< 0 ||
5345 (p
->mm
&& param
->sched_priority
> MAX_USER_RT_PRIO
-1) ||
5346 (!p
->mm
&& param
->sched_priority
> MAX_RT_PRIO
-1))
5348 if (rt_policy(policy
) != (param
->sched_priority
!= 0))
5352 * Allow unprivileged RT tasks to decrease priority:
5354 if (user
&& !capable(CAP_SYS_NICE
)) {
5355 if (rt_policy(policy
)) {
5356 unsigned long rlim_rtprio
;
5358 if (!lock_task_sighand(p
, &flags
))
5360 rlim_rtprio
= p
->signal
->rlim
[RLIMIT_RTPRIO
].rlim_cur
;
5361 unlock_task_sighand(p
, &flags
);
5363 /* can't set/change the rt policy */
5364 if (policy
!= p
->policy
&& !rlim_rtprio
)
5367 /* can't increase priority */
5368 if (param
->sched_priority
> p
->rt_priority
&&
5369 param
->sched_priority
> rlim_rtprio
)
5373 * Like positive nice levels, dont allow tasks to
5374 * move out of SCHED_IDLE either:
5376 if (p
->policy
== SCHED_IDLE
&& policy
!= SCHED_IDLE
)
5379 /* can't change other user's priorities */
5380 if (!check_same_owner(p
))
5385 #ifdef CONFIG_RT_GROUP_SCHED
5387 * Do not allow realtime tasks into groups that have no runtime
5390 if (rt_bandwidth_enabled() && rt_policy(policy
) &&
5391 task_group(p
)->rt_bandwidth
.rt_runtime
== 0)
5395 retval
= security_task_setscheduler(p
, policy
, param
);
5401 * make sure no PI-waiters arrive (or leave) while we are
5402 * changing the priority of the task:
5404 spin_lock_irqsave(&p
->pi_lock
, flags
);
5406 * To be able to change p->policy safely, the apropriate
5407 * runqueue lock must be held.
5409 rq
= __task_rq_lock(p
);
5410 /* recheck policy now with rq lock held */
5411 if (unlikely(oldpolicy
!= -1 && oldpolicy
!= p
->policy
)) {
5412 policy
= oldpolicy
= -1;
5413 __task_rq_unlock(rq
);
5414 spin_unlock_irqrestore(&p
->pi_lock
, flags
);
5417 update_rq_clock(rq
);
5418 on_rq
= p
->se
.on_rq
;
5419 running
= task_current(rq
, p
);
5421 deactivate_task(rq
, p
, 0);
5423 p
->sched_class
->put_prev_task(rq
, p
);
5426 __setscheduler(rq
, p
, policy
, param
->sched_priority
);
5429 p
->sched_class
->set_curr_task(rq
);
5431 activate_task(rq
, p
, 0);
5433 check_class_changed(rq
, p
, prev_class
, oldprio
, running
);
5435 __task_rq_unlock(rq
);
5436 spin_unlock_irqrestore(&p
->pi_lock
, flags
);
5438 rt_mutex_adjust_pi(p
);
5444 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
5445 * @p: the task in question.
5446 * @policy: new policy.
5447 * @param: structure containing the new RT priority.
5449 * NOTE that the task may be already dead.
5451 int sched_setscheduler(struct task_struct
*p
, int policy
,
5452 struct sched_param
*param
)
5454 return __sched_setscheduler(p
, policy
, param
, true);
5456 EXPORT_SYMBOL_GPL(sched_setscheduler
);
5459 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
5460 * @p: the task in question.
5461 * @policy: new policy.
5462 * @param: structure containing the new RT priority.
5464 * Just like sched_setscheduler, only don't bother checking if the
5465 * current context has permission. For example, this is needed in
5466 * stop_machine(): we create temporary high priority worker threads,
5467 * but our caller might not have that capability.
5469 int sched_setscheduler_nocheck(struct task_struct
*p
, int policy
,
5470 struct sched_param
*param
)
5472 return __sched_setscheduler(p
, policy
, param
, false);
5476 do_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
5478 struct sched_param lparam
;
5479 struct task_struct
*p
;
5482 if (!param
|| pid
< 0)
5484 if (copy_from_user(&lparam
, param
, sizeof(struct sched_param
)))
5489 p
= find_process_by_pid(pid
);
5491 retval
= sched_setscheduler(p
, policy
, &lparam
);
5498 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
5499 * @pid: the pid in question.
5500 * @policy: new policy.
5501 * @param: structure containing the new RT priority.
5504 sys_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
5506 /* negative values for policy are not valid */
5510 return do_sched_setscheduler(pid
, policy
, param
);
5514 * sys_sched_setparam - set/change the RT priority of a thread
5515 * @pid: the pid in question.
5516 * @param: structure containing the new RT priority.
5518 asmlinkage
long sys_sched_setparam(pid_t pid
, struct sched_param __user
*param
)
5520 return do_sched_setscheduler(pid
, -1, param
);
5524 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
5525 * @pid: the pid in question.
5527 asmlinkage
long sys_sched_getscheduler(pid_t pid
)
5529 struct task_struct
*p
;
5536 read_lock(&tasklist_lock
);
5537 p
= find_process_by_pid(pid
);
5539 retval
= security_task_getscheduler(p
);
5543 read_unlock(&tasklist_lock
);
5548 * sys_sched_getscheduler - get the RT priority of a thread
5549 * @pid: the pid in question.
5550 * @param: structure containing the RT priority.
5552 asmlinkage
long sys_sched_getparam(pid_t pid
, struct sched_param __user
*param
)
5554 struct sched_param lp
;
5555 struct task_struct
*p
;
5558 if (!param
|| pid
< 0)
5561 read_lock(&tasklist_lock
);
5562 p
= find_process_by_pid(pid
);
5567 retval
= security_task_getscheduler(p
);
5571 lp
.sched_priority
= p
->rt_priority
;
5572 read_unlock(&tasklist_lock
);
5575 * This one might sleep, we cannot do it with a spinlock held ...
5577 retval
= copy_to_user(param
, &lp
, sizeof(*param
)) ? -EFAULT
: 0;
5582 read_unlock(&tasklist_lock
);
5586 long sched_setaffinity(pid_t pid
, const struct cpumask
*in_mask
)
5588 cpumask_var_t cpus_allowed
, new_mask
;
5589 struct task_struct
*p
;
5593 read_lock(&tasklist_lock
);
5595 p
= find_process_by_pid(pid
);
5597 read_unlock(&tasklist_lock
);
5603 * It is not safe to call set_cpus_allowed with the
5604 * tasklist_lock held. We will bump the task_struct's
5605 * usage count and then drop tasklist_lock.
5608 read_unlock(&tasklist_lock
);
5610 if (!alloc_cpumask_var(&cpus_allowed
, GFP_KERNEL
)) {
5614 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
)) {
5616 goto out_free_cpus_allowed
;
5619 if (!check_same_owner(p
) && !capable(CAP_SYS_NICE
))
5622 retval
= security_task_setscheduler(p
, 0, NULL
);
5626 cpuset_cpus_allowed(p
, cpus_allowed
);
5627 cpumask_and(new_mask
, in_mask
, cpus_allowed
);
5629 retval
= set_cpus_allowed_ptr(p
, new_mask
);
5632 cpuset_cpus_allowed(p
, cpus_allowed
);
5633 if (!cpumask_subset(new_mask
, cpus_allowed
)) {
5635 * We must have raced with a concurrent cpuset
5636 * update. Just reset the cpus_allowed to the
5637 * cpuset's cpus_allowed
5639 cpumask_copy(new_mask
, cpus_allowed
);
5644 free_cpumask_var(new_mask
);
5645 out_free_cpus_allowed
:
5646 free_cpumask_var(cpus_allowed
);
5653 static int get_user_cpu_mask(unsigned long __user
*user_mask_ptr
, unsigned len
,
5654 struct cpumask
*new_mask
)
5656 if (len
< cpumask_size())
5657 cpumask_clear(new_mask
);
5658 else if (len
> cpumask_size())
5659 len
= cpumask_size();
5661 return copy_from_user(new_mask
, user_mask_ptr
, len
) ? -EFAULT
: 0;
5665 * sys_sched_setaffinity - set the cpu affinity of a process
5666 * @pid: pid of the process
5667 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
5668 * @user_mask_ptr: user-space pointer to the new cpu mask
5670 asmlinkage
long sys_sched_setaffinity(pid_t pid
, unsigned int len
,
5671 unsigned long __user
*user_mask_ptr
)
5673 cpumask_var_t new_mask
;
5676 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
))
5679 retval
= get_user_cpu_mask(user_mask_ptr
, len
, new_mask
);
5681 retval
= sched_setaffinity(pid
, new_mask
);
5682 free_cpumask_var(new_mask
);
5686 long sched_getaffinity(pid_t pid
, struct cpumask
*mask
)
5688 struct task_struct
*p
;
5692 read_lock(&tasklist_lock
);
5695 p
= find_process_by_pid(pid
);
5699 retval
= security_task_getscheduler(p
);
5703 cpumask_and(mask
, &p
->cpus_allowed
, cpu_online_mask
);
5706 read_unlock(&tasklist_lock
);
5713 * sys_sched_getaffinity - get the cpu affinity of a process
5714 * @pid: pid of the process
5715 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
5716 * @user_mask_ptr: user-space pointer to hold the current cpu mask
5718 asmlinkage
long sys_sched_getaffinity(pid_t pid
, unsigned int len
,
5719 unsigned long __user
*user_mask_ptr
)
5724 if (len
< cpumask_size())
5727 if (!alloc_cpumask_var(&mask
, GFP_KERNEL
))
5730 ret
= sched_getaffinity(pid
, mask
);
5732 if (copy_to_user(user_mask_ptr
, mask
, cpumask_size()))
5735 ret
= cpumask_size();
5737 free_cpumask_var(mask
);
5743 * sys_sched_yield - yield the current processor to other threads.
5745 * This function yields the current CPU to other tasks. If there are no
5746 * other threads running on this CPU then this function will return.
5748 asmlinkage
long sys_sched_yield(void)
5750 struct rq
*rq
= this_rq_lock();
5752 schedstat_inc(rq
, yld_count
);
5753 current
->sched_class
->yield_task(rq
);
5756 * Since we are going to call schedule() anyway, there's
5757 * no need to preempt or enable interrupts:
5759 __release(rq
->lock
);
5760 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
5761 _raw_spin_unlock(&rq
->lock
);
5762 preempt_enable_no_resched();
5769 static void __cond_resched(void)
5771 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
5772 __might_sleep(__FILE__
, __LINE__
);
5775 * The BKS might be reacquired before we have dropped
5776 * PREEMPT_ACTIVE, which could trigger a second
5777 * cond_resched() call.
5780 add_preempt_count(PREEMPT_ACTIVE
);
5782 sub_preempt_count(PREEMPT_ACTIVE
);
5783 } while (need_resched());
5786 int __sched
_cond_resched(void)
5788 if (need_resched() && !(preempt_count() & PREEMPT_ACTIVE
) &&
5789 system_state
== SYSTEM_RUNNING
) {
5795 EXPORT_SYMBOL(_cond_resched
);
5798 * cond_resched_lock() - if a reschedule is pending, drop the given lock,
5799 * call schedule, and on return reacquire the lock.
5801 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
5802 * operations here to prevent schedule() from being called twice (once via
5803 * spin_unlock(), once by hand).
5805 int cond_resched_lock(spinlock_t
*lock
)
5807 int resched
= need_resched() && system_state
== SYSTEM_RUNNING
;
5810 if (spin_needbreak(lock
) || resched
) {
5812 if (resched
&& need_resched())
5821 EXPORT_SYMBOL(cond_resched_lock
);
5823 int __sched
cond_resched_softirq(void)
5825 BUG_ON(!in_softirq());
5827 if (need_resched() && system_state
== SYSTEM_RUNNING
) {
5835 EXPORT_SYMBOL(cond_resched_softirq
);
5838 * yield - yield the current processor to other threads.
5840 * This is a shortcut for kernel-space yielding - it marks the
5841 * thread runnable and calls sys_sched_yield().
5843 void __sched
yield(void)
5845 set_current_state(TASK_RUNNING
);
5848 EXPORT_SYMBOL(yield
);
5851 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
5852 * that process accounting knows that this is a task in IO wait state.
5854 * But don't do that if it is a deliberate, throttling IO wait (this task
5855 * has set its backing_dev_info: the queue against which it should throttle)
5857 void __sched
io_schedule(void)
5859 struct rq
*rq
= &__raw_get_cpu_var(runqueues
);
5861 delayacct_blkio_start();
5862 atomic_inc(&rq
->nr_iowait
);
5864 atomic_dec(&rq
->nr_iowait
);
5865 delayacct_blkio_end();
5867 EXPORT_SYMBOL(io_schedule
);
5869 long __sched
io_schedule_timeout(long timeout
)
5871 struct rq
*rq
= &__raw_get_cpu_var(runqueues
);
5874 delayacct_blkio_start();
5875 atomic_inc(&rq
->nr_iowait
);
5876 ret
= schedule_timeout(timeout
);
5877 atomic_dec(&rq
->nr_iowait
);
5878 delayacct_blkio_end();
5883 * sys_sched_get_priority_max - return maximum RT priority.
5884 * @policy: scheduling class.
5886 * this syscall returns the maximum rt_priority that can be used
5887 * by a given scheduling class.
5889 asmlinkage
long sys_sched_get_priority_max(int policy
)
5896 ret
= MAX_USER_RT_PRIO
-1;
5908 * sys_sched_get_priority_min - return minimum RT priority.
5909 * @policy: scheduling class.
5911 * this syscall returns the minimum rt_priority that can be used
5912 * by a given scheduling class.
5914 asmlinkage
long sys_sched_get_priority_min(int policy
)
5932 * sys_sched_rr_get_interval - return the default timeslice of a process.
5933 * @pid: pid of the process.
5934 * @interval: userspace pointer to the timeslice value.
5936 * this syscall writes the default timeslice value of a given process
5937 * into the user-space timespec buffer. A value of '0' means infinity.
5940 long sys_sched_rr_get_interval(pid_t pid
, struct timespec __user
*interval
)
5942 struct task_struct
*p
;
5943 unsigned int time_slice
;
5951 read_lock(&tasklist_lock
);
5952 p
= find_process_by_pid(pid
);
5956 retval
= security_task_getscheduler(p
);
5961 * Time slice is 0 for SCHED_FIFO tasks and for SCHED_OTHER
5962 * tasks that are on an otherwise idle runqueue:
5965 if (p
->policy
== SCHED_RR
) {
5966 time_slice
= DEF_TIMESLICE
;
5967 } else if (p
->policy
!= SCHED_FIFO
) {
5968 struct sched_entity
*se
= &p
->se
;
5969 unsigned long flags
;
5972 rq
= task_rq_lock(p
, &flags
);
5973 if (rq
->cfs
.load
.weight
)
5974 time_slice
= NS_TO_JIFFIES(sched_slice(&rq
->cfs
, se
));
5975 task_rq_unlock(rq
, &flags
);
5977 read_unlock(&tasklist_lock
);
5978 jiffies_to_timespec(time_slice
, &t
);
5979 retval
= copy_to_user(interval
, &t
, sizeof(t
)) ? -EFAULT
: 0;
5983 read_unlock(&tasklist_lock
);
5987 static const char stat_nam
[] = TASK_STATE_TO_CHAR_STR
;
5989 void sched_show_task(struct task_struct
*p
)
5991 unsigned long free
= 0;
5994 state
= p
->state
? __ffs(p
->state
) + 1 : 0;
5995 printk(KERN_INFO
"%-13.13s %c", p
->comm
,
5996 state
< sizeof(stat_nam
) - 1 ? stat_nam
[state
] : '?');
5997 #if BITS_PER_LONG == 32
5998 if (state
== TASK_RUNNING
)
5999 printk(KERN_CONT
" running ");
6001 printk(KERN_CONT
" %08lx ", thread_saved_pc(p
));
6003 if (state
== TASK_RUNNING
)
6004 printk(KERN_CONT
" running task ");
6006 printk(KERN_CONT
" %016lx ", thread_saved_pc(p
));
6008 #ifdef CONFIG_DEBUG_STACK_USAGE
6010 unsigned long *n
= end_of_stack(p
);
6013 free
= (unsigned long)n
- (unsigned long)end_of_stack(p
);
6016 printk(KERN_CONT
"%5lu %5d %6d\n", free
,
6017 task_pid_nr(p
), task_pid_nr(p
->real_parent
));
6019 show_stack(p
, NULL
);
6022 void show_state_filter(unsigned long state_filter
)
6024 struct task_struct
*g
, *p
;
6026 #if BITS_PER_LONG == 32
6028 " task PC stack pid father\n");
6031 " task PC stack pid father\n");
6033 read_lock(&tasklist_lock
);
6034 do_each_thread(g
, p
) {
6036 * reset the NMI-timeout, listing all files on a slow
6037 * console might take alot of time:
6039 touch_nmi_watchdog();
6040 if (!state_filter
|| (p
->state
& state_filter
))
6042 } while_each_thread(g
, p
);
6044 touch_all_softlockup_watchdogs();
6046 #ifdef CONFIG_SCHED_DEBUG
6047 sysrq_sched_debug_show();
6049 read_unlock(&tasklist_lock
);
6051 * Only show locks if all tasks are dumped:
6053 if (state_filter
== -1)
6054 debug_show_all_locks();
6057 void __cpuinit
init_idle_bootup_task(struct task_struct
*idle
)
6059 idle
->sched_class
= &idle_sched_class
;
6063 * init_idle - set up an idle thread for a given CPU
6064 * @idle: task in question
6065 * @cpu: cpu the idle task belongs to
6067 * NOTE: this function does not set the idle thread's NEED_RESCHED
6068 * flag, to make booting more robust.
6070 void __cpuinit
init_idle(struct task_struct
*idle
, int cpu
)
6072 struct rq
*rq
= cpu_rq(cpu
);
6073 unsigned long flags
;
6075 spin_lock_irqsave(&rq
->lock
, flags
);
6078 idle
->se
.exec_start
= sched_clock();
6080 idle
->prio
= idle
->normal_prio
= MAX_PRIO
;
6081 cpumask_copy(&idle
->cpus_allowed
, cpumask_of(cpu
));
6082 __set_task_cpu(idle
, cpu
);
6084 rq
->curr
= rq
->idle
= idle
;
6085 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
6088 spin_unlock_irqrestore(&rq
->lock
, flags
);
6090 /* Set the preempt count _outside_ the spinlocks! */
6091 #if defined(CONFIG_PREEMPT)
6092 task_thread_info(idle
)->preempt_count
= (idle
->lock_depth
>= 0);
6094 task_thread_info(idle
)->preempt_count
= 0;
6097 * The idle tasks have their own, simple scheduling class:
6099 idle
->sched_class
= &idle_sched_class
;
6100 ftrace_graph_init_task(idle
);
6104 * In a system that switches off the HZ timer nohz_cpu_mask
6105 * indicates which cpus entered this state. This is used
6106 * in the rcu update to wait only for active cpus. For system
6107 * which do not switch off the HZ timer nohz_cpu_mask should
6108 * always be CPU_BITS_NONE.
6110 cpumask_var_t nohz_cpu_mask
;
6113 * Increase the granularity value when there are more CPUs,
6114 * because with more CPUs the 'effective latency' as visible
6115 * to users decreases. But the relationship is not linear,
6116 * so pick a second-best guess by going with the log2 of the
6119 * This idea comes from the SD scheduler of Con Kolivas:
6121 static inline void sched_init_granularity(void)
6123 unsigned int factor
= 1 + ilog2(num_online_cpus());
6124 const unsigned long limit
= 200000000;
6126 sysctl_sched_min_granularity
*= factor
;
6127 if (sysctl_sched_min_granularity
> limit
)
6128 sysctl_sched_min_granularity
= limit
;
6130 sysctl_sched_latency
*= factor
;
6131 if (sysctl_sched_latency
> limit
)
6132 sysctl_sched_latency
= limit
;
6134 sysctl_sched_wakeup_granularity
*= factor
;
6136 sysctl_sched_shares_ratelimit
*= factor
;
6141 * This is how migration works:
6143 * 1) we queue a struct migration_req structure in the source CPU's
6144 * runqueue and wake up that CPU's migration thread.
6145 * 2) we down() the locked semaphore => thread blocks.
6146 * 3) migration thread wakes up (implicitly it forces the migrated
6147 * thread off the CPU)
6148 * 4) it gets the migration request and checks whether the migrated
6149 * task is still in the wrong runqueue.
6150 * 5) if it's in the wrong runqueue then the migration thread removes
6151 * it and puts it into the right queue.
6152 * 6) migration thread up()s the semaphore.
6153 * 7) we wake up and the migration is done.
6157 * Change a given task's CPU affinity. Migrate the thread to a
6158 * proper CPU and schedule it away if the CPU it's executing on
6159 * is removed from the allowed bitmask.
6161 * NOTE: the caller must have a valid reference to the task, the
6162 * task must not exit() & deallocate itself prematurely. The
6163 * call is not atomic; no spinlocks may be held.
6165 int set_cpus_allowed_ptr(struct task_struct
*p
, const struct cpumask
*new_mask
)
6167 struct migration_req req
;
6168 unsigned long flags
;
6172 rq
= task_rq_lock(p
, &flags
);
6173 if (!cpumask_intersects(new_mask
, cpu_online_mask
)) {
6178 if (unlikely((p
->flags
& PF_THREAD_BOUND
) && p
!= current
&&
6179 !cpumask_equal(&p
->cpus_allowed
, new_mask
))) {
6184 if (p
->sched_class
->set_cpus_allowed
)
6185 p
->sched_class
->set_cpus_allowed(p
, new_mask
);
6187 cpumask_copy(&p
->cpus_allowed
, new_mask
);
6188 p
->rt
.nr_cpus_allowed
= cpumask_weight(new_mask
);
6191 /* Can the task run on the task's current CPU? If so, we're done */
6192 if (cpumask_test_cpu(task_cpu(p
), new_mask
))
6195 if (migrate_task(p
, cpumask_any_and(cpu_online_mask
, new_mask
), &req
)) {
6196 /* Need help from migration thread: drop lock and wait. */
6197 task_rq_unlock(rq
, &flags
);
6198 wake_up_process(rq
->migration_thread
);
6199 wait_for_completion(&req
.done
);
6200 tlb_migrate_finish(p
->mm
);
6204 task_rq_unlock(rq
, &flags
);
6208 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr
);
6211 * Move (not current) task off this cpu, onto dest cpu. We're doing
6212 * this because either it can't run here any more (set_cpus_allowed()
6213 * away from this CPU, or CPU going down), or because we're
6214 * attempting to rebalance this task on exec (sched_exec).
6216 * So we race with normal scheduler movements, but that's OK, as long
6217 * as the task is no longer on this CPU.
6219 * Returns non-zero if task was successfully migrated.
6221 static int __migrate_task(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
6223 struct rq
*rq_dest
, *rq_src
;
6226 if (unlikely(!cpu_active(dest_cpu
)))
6229 rq_src
= cpu_rq(src_cpu
);
6230 rq_dest
= cpu_rq(dest_cpu
);
6232 double_rq_lock(rq_src
, rq_dest
);
6233 /* Already moved. */
6234 if (task_cpu(p
) != src_cpu
)
6236 /* Affinity changed (again). */
6237 if (!cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
))
6240 on_rq
= p
->se
.on_rq
;
6242 deactivate_task(rq_src
, p
, 0);
6244 set_task_cpu(p
, dest_cpu
);
6246 activate_task(rq_dest
, p
, 0);
6247 check_preempt_curr(rq_dest
, p
, 0);
6252 double_rq_unlock(rq_src
, rq_dest
);
6257 * migration_thread - this is a highprio system thread that performs
6258 * thread migration by bumping thread off CPU then 'pushing' onto
6261 static int migration_thread(void *data
)
6263 int cpu
= (long)data
;
6267 BUG_ON(rq
->migration_thread
!= current
);
6269 set_current_state(TASK_INTERRUPTIBLE
);
6270 while (!kthread_should_stop()) {
6271 struct migration_req
*req
;
6272 struct list_head
*head
;
6274 spin_lock_irq(&rq
->lock
);
6276 if (cpu_is_offline(cpu
)) {
6277 spin_unlock_irq(&rq
->lock
);
6281 if (rq
->active_balance
) {
6282 active_load_balance(rq
, cpu
);
6283 rq
->active_balance
= 0;
6286 head
= &rq
->migration_queue
;
6288 if (list_empty(head
)) {
6289 spin_unlock_irq(&rq
->lock
);
6291 set_current_state(TASK_INTERRUPTIBLE
);
6294 req
= list_entry(head
->next
, struct migration_req
, list
);
6295 list_del_init(head
->next
);
6297 spin_unlock(&rq
->lock
);
6298 __migrate_task(req
->task
, cpu
, req
->dest_cpu
);
6301 complete(&req
->done
);
6303 __set_current_state(TASK_RUNNING
);
6307 /* Wait for kthread_stop */
6308 set_current_state(TASK_INTERRUPTIBLE
);
6309 while (!kthread_should_stop()) {
6311 set_current_state(TASK_INTERRUPTIBLE
);
6313 __set_current_state(TASK_RUNNING
);
6317 #ifdef CONFIG_HOTPLUG_CPU
6319 static int __migrate_task_irq(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
6323 local_irq_disable();
6324 ret
= __migrate_task(p
, src_cpu
, dest_cpu
);
6330 * Figure out where task on dead CPU should go, use force if necessary.
6332 static void move_task_off_dead_cpu(int dead_cpu
, struct task_struct
*p
)
6335 const struct cpumask
*nodemask
= cpumask_of_node(cpu_to_node(dead_cpu
));
6338 /* Look for allowed, online CPU in same node. */
6339 for_each_cpu_and(dest_cpu
, nodemask
, cpu_online_mask
)
6340 if (cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
))
6343 /* Any allowed, online CPU? */
6344 dest_cpu
= cpumask_any_and(&p
->cpus_allowed
, cpu_online_mask
);
6345 if (dest_cpu
< nr_cpu_ids
)
6348 /* No more Mr. Nice Guy. */
6349 if (dest_cpu
>= nr_cpu_ids
) {
6350 cpuset_cpus_allowed_locked(p
, &p
->cpus_allowed
);
6351 dest_cpu
= cpumask_any_and(cpu_online_mask
, &p
->cpus_allowed
);
6354 * Don't tell them about moving exiting tasks or
6355 * kernel threads (both mm NULL), since they never
6358 if (p
->mm
&& printk_ratelimit()) {
6359 printk(KERN_INFO
"process %d (%s) no "
6360 "longer affine to cpu%d\n",
6361 task_pid_nr(p
), p
->comm
, dead_cpu
);
6366 /* It can have affinity changed while we were choosing. */
6367 if (unlikely(!__migrate_task_irq(p
, dead_cpu
, dest_cpu
)))
6372 * While a dead CPU has no uninterruptible tasks queued at this point,
6373 * it might still have a nonzero ->nr_uninterruptible counter, because
6374 * for performance reasons the counter is not stricly tracking tasks to
6375 * their home CPUs. So we just add the counter to another CPU's counter,
6376 * to keep the global sum constant after CPU-down:
6378 static void migrate_nr_uninterruptible(struct rq
*rq_src
)
6380 struct rq
*rq_dest
= cpu_rq(cpumask_any(cpu_online_mask
));
6381 unsigned long flags
;
6383 local_irq_save(flags
);
6384 double_rq_lock(rq_src
, rq_dest
);
6385 rq_dest
->nr_uninterruptible
+= rq_src
->nr_uninterruptible
;
6386 rq_src
->nr_uninterruptible
= 0;
6387 double_rq_unlock(rq_src
, rq_dest
);
6388 local_irq_restore(flags
);
6391 /* Run through task list and migrate tasks from the dead cpu. */
6392 static void migrate_live_tasks(int src_cpu
)
6394 struct task_struct
*p
, *t
;
6396 read_lock(&tasklist_lock
);
6398 do_each_thread(t
, p
) {
6402 if (task_cpu(p
) == src_cpu
)
6403 move_task_off_dead_cpu(src_cpu
, p
);
6404 } while_each_thread(t
, p
);
6406 read_unlock(&tasklist_lock
);
6410 * Schedules idle task to be the next runnable task on current CPU.
6411 * It does so by boosting its priority to highest possible.
6412 * Used by CPU offline code.
6414 void sched_idle_next(void)
6416 int this_cpu
= smp_processor_id();
6417 struct rq
*rq
= cpu_rq(this_cpu
);
6418 struct task_struct
*p
= rq
->idle
;
6419 unsigned long flags
;
6421 /* cpu has to be offline */
6422 BUG_ON(cpu_online(this_cpu
));
6425 * Strictly not necessary since rest of the CPUs are stopped by now
6426 * and interrupts disabled on the current cpu.
6428 spin_lock_irqsave(&rq
->lock
, flags
);
6430 __setscheduler(rq
, p
, SCHED_FIFO
, MAX_RT_PRIO
-1);
6432 update_rq_clock(rq
);
6433 activate_task(rq
, p
, 0);
6435 spin_unlock_irqrestore(&rq
->lock
, flags
);
6439 * Ensures that the idle task is using init_mm right before its cpu goes
6442 void idle_task_exit(void)
6444 struct mm_struct
*mm
= current
->active_mm
;
6446 BUG_ON(cpu_online(smp_processor_id()));
6449 switch_mm(mm
, &init_mm
, current
);
6453 /* called under rq->lock with disabled interrupts */
6454 static void migrate_dead(unsigned int dead_cpu
, struct task_struct
*p
)
6456 struct rq
*rq
= cpu_rq(dead_cpu
);
6458 /* Must be exiting, otherwise would be on tasklist. */
6459 BUG_ON(!p
->exit_state
);
6461 /* Cannot have done final schedule yet: would have vanished. */
6462 BUG_ON(p
->state
== TASK_DEAD
);
6467 * Drop lock around migration; if someone else moves it,
6468 * that's OK. No task can be added to this CPU, so iteration is
6471 spin_unlock_irq(&rq
->lock
);
6472 move_task_off_dead_cpu(dead_cpu
, p
);
6473 spin_lock_irq(&rq
->lock
);
6478 /* release_task() removes task from tasklist, so we won't find dead tasks. */
6479 static void migrate_dead_tasks(unsigned int dead_cpu
)
6481 struct rq
*rq
= cpu_rq(dead_cpu
);
6482 struct task_struct
*next
;
6485 if (!rq
->nr_running
)
6487 update_rq_clock(rq
);
6488 next
= pick_next_task(rq
, rq
->curr
);
6491 next
->sched_class
->put_prev_task(rq
, next
);
6492 migrate_dead(dead_cpu
, next
);
6496 #endif /* CONFIG_HOTPLUG_CPU */
6498 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
6500 static struct ctl_table sd_ctl_dir
[] = {
6502 .procname
= "sched_domain",
6508 static struct ctl_table sd_ctl_root
[] = {
6510 .ctl_name
= CTL_KERN
,
6511 .procname
= "kernel",
6513 .child
= sd_ctl_dir
,
6518 static struct ctl_table
*sd_alloc_ctl_entry(int n
)
6520 struct ctl_table
*entry
=
6521 kcalloc(n
, sizeof(struct ctl_table
), GFP_KERNEL
);
6526 static void sd_free_ctl_entry(struct ctl_table
**tablep
)
6528 struct ctl_table
*entry
;
6531 * In the intermediate directories, both the child directory and
6532 * procname are dynamically allocated and could fail but the mode
6533 * will always be set. In the lowest directory the names are
6534 * static strings and all have proc handlers.
6536 for (entry
= *tablep
; entry
->mode
; entry
++) {
6538 sd_free_ctl_entry(&entry
->child
);
6539 if (entry
->proc_handler
== NULL
)
6540 kfree(entry
->procname
);
6548 set_table_entry(struct ctl_table
*entry
,
6549 const char *procname
, void *data
, int maxlen
,
6550 mode_t mode
, proc_handler
*proc_handler
)
6552 entry
->procname
= procname
;
6554 entry
->maxlen
= maxlen
;
6556 entry
->proc_handler
= proc_handler
;
6559 static struct ctl_table
*
6560 sd_alloc_ctl_domain_table(struct sched_domain
*sd
)
6562 struct ctl_table
*table
= sd_alloc_ctl_entry(13);
6567 set_table_entry(&table
[0], "min_interval", &sd
->min_interval
,
6568 sizeof(long), 0644, proc_doulongvec_minmax
);
6569 set_table_entry(&table
[1], "max_interval", &sd
->max_interval
,
6570 sizeof(long), 0644, proc_doulongvec_minmax
);
6571 set_table_entry(&table
[2], "busy_idx", &sd
->busy_idx
,
6572 sizeof(int), 0644, proc_dointvec_minmax
);
6573 set_table_entry(&table
[3], "idle_idx", &sd
->idle_idx
,
6574 sizeof(int), 0644, proc_dointvec_minmax
);
6575 set_table_entry(&table
[4], "newidle_idx", &sd
->newidle_idx
,
6576 sizeof(int), 0644, proc_dointvec_minmax
);
6577 set_table_entry(&table
[5], "wake_idx", &sd
->wake_idx
,
6578 sizeof(int), 0644, proc_dointvec_minmax
);
6579 set_table_entry(&table
[6], "forkexec_idx", &sd
->forkexec_idx
,
6580 sizeof(int), 0644, proc_dointvec_minmax
);
6581 set_table_entry(&table
[7], "busy_factor", &sd
->busy_factor
,
6582 sizeof(int), 0644, proc_dointvec_minmax
);
6583 set_table_entry(&table
[8], "imbalance_pct", &sd
->imbalance_pct
,
6584 sizeof(int), 0644, proc_dointvec_minmax
);
6585 set_table_entry(&table
[9], "cache_nice_tries",
6586 &sd
->cache_nice_tries
,
6587 sizeof(int), 0644, proc_dointvec_minmax
);
6588 set_table_entry(&table
[10], "flags", &sd
->flags
,
6589 sizeof(int), 0644, proc_dointvec_minmax
);
6590 set_table_entry(&table
[11], "name", sd
->name
,
6591 CORENAME_MAX_SIZE
, 0444, proc_dostring
);
6592 /* &table[12] is terminator */
6597 static ctl_table
*sd_alloc_ctl_cpu_table(int cpu
)
6599 struct ctl_table
*entry
, *table
;
6600 struct sched_domain
*sd
;
6601 int domain_num
= 0, i
;
6604 for_each_domain(cpu
, sd
)
6606 entry
= table
= sd_alloc_ctl_entry(domain_num
+ 1);
6611 for_each_domain(cpu
, sd
) {
6612 snprintf(buf
, 32, "domain%d", i
);
6613 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
6615 entry
->child
= sd_alloc_ctl_domain_table(sd
);
6622 static struct ctl_table_header
*sd_sysctl_header
;
6623 static void register_sched_domain_sysctl(void)
6625 int i
, cpu_num
= num_online_cpus();
6626 struct ctl_table
*entry
= sd_alloc_ctl_entry(cpu_num
+ 1);
6629 WARN_ON(sd_ctl_dir
[0].child
);
6630 sd_ctl_dir
[0].child
= entry
;
6635 for_each_online_cpu(i
) {
6636 snprintf(buf
, 32, "cpu%d", i
);
6637 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
6639 entry
->child
= sd_alloc_ctl_cpu_table(i
);
6643 WARN_ON(sd_sysctl_header
);
6644 sd_sysctl_header
= register_sysctl_table(sd_ctl_root
);
6647 /* may be called multiple times per register */
6648 static void unregister_sched_domain_sysctl(void)
6650 if (sd_sysctl_header
)
6651 unregister_sysctl_table(sd_sysctl_header
);
6652 sd_sysctl_header
= NULL
;
6653 if (sd_ctl_dir
[0].child
)
6654 sd_free_ctl_entry(&sd_ctl_dir
[0].child
);
6657 static void register_sched_domain_sysctl(void)
6660 static void unregister_sched_domain_sysctl(void)
6665 static void set_rq_online(struct rq
*rq
)
6668 const struct sched_class
*class;
6670 cpumask_set_cpu(rq
->cpu
, rq
->rd
->online
);
6673 for_each_class(class) {
6674 if (class->rq_online
)
6675 class->rq_online(rq
);
6680 static void set_rq_offline(struct rq
*rq
)
6683 const struct sched_class
*class;
6685 for_each_class(class) {
6686 if (class->rq_offline
)
6687 class->rq_offline(rq
);
6690 cpumask_clear_cpu(rq
->cpu
, rq
->rd
->online
);
6696 * migration_call - callback that gets triggered when a CPU is added.
6697 * Here we can start up the necessary migration thread for the new CPU.
6699 static int __cpuinit
6700 migration_call(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
6702 struct task_struct
*p
;
6703 int cpu
= (long)hcpu
;
6704 unsigned long flags
;
6709 case CPU_UP_PREPARE
:
6710 case CPU_UP_PREPARE_FROZEN
:
6711 p
= kthread_create(migration_thread
, hcpu
, "migration/%d", cpu
);
6714 kthread_bind(p
, cpu
);
6715 /* Must be high prio: stop_machine expects to yield to it. */
6716 rq
= task_rq_lock(p
, &flags
);
6717 __setscheduler(rq
, p
, SCHED_FIFO
, MAX_RT_PRIO
-1);
6718 task_rq_unlock(rq
, &flags
);
6719 cpu_rq(cpu
)->migration_thread
= p
;
6723 case CPU_ONLINE_FROZEN
:
6724 /* Strictly unnecessary, as first user will wake it. */
6725 wake_up_process(cpu_rq(cpu
)->migration_thread
);
6727 /* Update our root-domain */
6729 spin_lock_irqsave(&rq
->lock
, flags
);
6731 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
6735 spin_unlock_irqrestore(&rq
->lock
, flags
);
6738 #ifdef CONFIG_HOTPLUG_CPU
6739 case CPU_UP_CANCELED
:
6740 case CPU_UP_CANCELED_FROZEN
:
6741 if (!cpu_rq(cpu
)->migration_thread
)
6743 /* Unbind it from offline cpu so it can run. Fall thru. */
6744 kthread_bind(cpu_rq(cpu
)->migration_thread
,
6745 cpumask_any(cpu_online_mask
));
6746 kthread_stop(cpu_rq(cpu
)->migration_thread
);
6747 cpu_rq(cpu
)->migration_thread
= NULL
;
6751 case CPU_DEAD_FROZEN
:
6752 cpuset_lock(); /* around calls to cpuset_cpus_allowed_lock() */
6753 migrate_live_tasks(cpu
);
6755 kthread_stop(rq
->migration_thread
);
6756 rq
->migration_thread
= NULL
;
6757 /* Idle task back to normal (off runqueue, low prio) */
6758 spin_lock_irq(&rq
->lock
);
6759 update_rq_clock(rq
);
6760 deactivate_task(rq
, rq
->idle
, 0);
6761 rq
->idle
->static_prio
= MAX_PRIO
;
6762 __setscheduler(rq
, rq
->idle
, SCHED_NORMAL
, 0);
6763 rq
->idle
->sched_class
= &idle_sched_class
;
6764 migrate_dead_tasks(cpu
);
6765 spin_unlock_irq(&rq
->lock
);
6767 migrate_nr_uninterruptible(rq
);
6768 BUG_ON(rq
->nr_running
!= 0);
6771 * No need to migrate the tasks: it was best-effort if
6772 * they didn't take sched_hotcpu_mutex. Just wake up
6775 spin_lock_irq(&rq
->lock
);
6776 while (!list_empty(&rq
->migration_queue
)) {
6777 struct migration_req
*req
;
6779 req
= list_entry(rq
->migration_queue
.next
,
6780 struct migration_req
, list
);
6781 list_del_init(&req
->list
);
6782 spin_unlock_irq(&rq
->lock
);
6783 complete(&req
->done
);
6784 spin_lock_irq(&rq
->lock
);
6786 spin_unlock_irq(&rq
->lock
);
6790 case CPU_DYING_FROZEN
:
6791 /* Update our root-domain */
6793 spin_lock_irqsave(&rq
->lock
, flags
);
6795 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
6798 spin_unlock_irqrestore(&rq
->lock
, flags
);
6805 /* Register at highest priority so that task migration (migrate_all_tasks)
6806 * happens before everything else.
6808 static struct notifier_block __cpuinitdata migration_notifier
= {
6809 .notifier_call
= migration_call
,
6813 static int __init
migration_init(void)
6815 void *cpu
= (void *)(long)smp_processor_id();
6818 /* Start one for the boot CPU: */
6819 err
= migration_call(&migration_notifier
, CPU_UP_PREPARE
, cpu
);
6820 BUG_ON(err
== NOTIFY_BAD
);
6821 migration_call(&migration_notifier
, CPU_ONLINE
, cpu
);
6822 register_cpu_notifier(&migration_notifier
);
6826 early_initcall(migration_init
);
6831 #ifdef CONFIG_SCHED_DEBUG
6833 static int sched_domain_debug_one(struct sched_domain
*sd
, int cpu
, int level
,
6834 struct cpumask
*groupmask
)
6836 struct sched_group
*group
= sd
->groups
;
6839 cpulist_scnprintf(str
, sizeof(str
), sched_domain_span(sd
));
6840 cpumask_clear(groupmask
);
6842 printk(KERN_DEBUG
"%*s domain %d: ", level
, "", level
);
6844 if (!(sd
->flags
& SD_LOAD_BALANCE
)) {
6845 printk("does not load-balance\n");
6847 printk(KERN_ERR
"ERROR: !SD_LOAD_BALANCE domain"
6852 printk(KERN_CONT
"span %s level %s\n", str
, sd
->name
);
6854 if (!cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
6855 printk(KERN_ERR
"ERROR: domain->span does not contain "
6858 if (!cpumask_test_cpu(cpu
, sched_group_cpus(group
))) {
6859 printk(KERN_ERR
"ERROR: domain->groups does not contain"
6863 printk(KERN_DEBUG
"%*s groups:", level
+ 1, "");
6867 printk(KERN_ERR
"ERROR: group is NULL\n");
6871 if (!group
->__cpu_power
) {
6872 printk(KERN_CONT
"\n");
6873 printk(KERN_ERR
"ERROR: domain->cpu_power not "
6878 if (!cpumask_weight(sched_group_cpus(group
))) {
6879 printk(KERN_CONT
"\n");
6880 printk(KERN_ERR
"ERROR: empty group\n");
6884 if (cpumask_intersects(groupmask
, sched_group_cpus(group
))) {
6885 printk(KERN_CONT
"\n");
6886 printk(KERN_ERR
"ERROR: repeated CPUs\n");
6890 cpumask_or(groupmask
, groupmask
, sched_group_cpus(group
));
6892 cpulist_scnprintf(str
, sizeof(str
), sched_group_cpus(group
));
6893 printk(KERN_CONT
" %s", str
);
6895 group
= group
->next
;
6896 } while (group
!= sd
->groups
);
6897 printk(KERN_CONT
"\n");
6899 if (!cpumask_equal(sched_domain_span(sd
), groupmask
))
6900 printk(KERN_ERR
"ERROR: groups don't span domain->span\n");
6903 !cpumask_subset(groupmask
, sched_domain_span(sd
->parent
)))
6904 printk(KERN_ERR
"ERROR: parent span is not a superset "
6905 "of domain->span\n");
6909 static void sched_domain_debug(struct sched_domain
*sd
, int cpu
)
6911 cpumask_var_t groupmask
;
6915 printk(KERN_DEBUG
"CPU%d attaching NULL sched-domain.\n", cpu
);
6919 printk(KERN_DEBUG
"CPU%d attaching sched-domain:\n", cpu
);
6921 if (!alloc_cpumask_var(&groupmask
, GFP_KERNEL
)) {
6922 printk(KERN_DEBUG
"Cannot load-balance (out of memory)\n");
6927 if (sched_domain_debug_one(sd
, cpu
, level
, groupmask
))
6934 free_cpumask_var(groupmask
);
6936 #else /* !CONFIG_SCHED_DEBUG */
6937 # define sched_domain_debug(sd, cpu) do { } while (0)
6938 #endif /* CONFIG_SCHED_DEBUG */
6940 static int sd_degenerate(struct sched_domain
*sd
)
6942 if (cpumask_weight(sched_domain_span(sd
)) == 1)
6945 /* Following flags need at least 2 groups */
6946 if (sd
->flags
& (SD_LOAD_BALANCE
|
6947 SD_BALANCE_NEWIDLE
|
6951 SD_SHARE_PKG_RESOURCES
)) {
6952 if (sd
->groups
!= sd
->groups
->next
)
6956 /* Following flags don't use groups */
6957 if (sd
->flags
& (SD_WAKE_IDLE
|
6966 sd_parent_degenerate(struct sched_domain
*sd
, struct sched_domain
*parent
)
6968 unsigned long cflags
= sd
->flags
, pflags
= parent
->flags
;
6970 if (sd_degenerate(parent
))
6973 if (!cpumask_equal(sched_domain_span(sd
), sched_domain_span(parent
)))
6976 /* Does parent contain flags not in child? */
6977 /* WAKE_BALANCE is a subset of WAKE_AFFINE */
6978 if (cflags
& SD_WAKE_AFFINE
)
6979 pflags
&= ~SD_WAKE_BALANCE
;
6980 /* Flags needing groups don't count if only 1 group in parent */
6981 if (parent
->groups
== parent
->groups
->next
) {
6982 pflags
&= ~(SD_LOAD_BALANCE
|
6983 SD_BALANCE_NEWIDLE
|
6987 SD_SHARE_PKG_RESOURCES
);
6988 if (nr_node_ids
== 1)
6989 pflags
&= ~SD_SERIALIZE
;
6991 if (~cflags
& pflags
)
6997 static void free_rootdomain(struct root_domain
*rd
)
6999 cpupri_cleanup(&rd
->cpupri
);
7001 free_cpumask_var(rd
->rto_mask
);
7002 free_cpumask_var(rd
->online
);
7003 free_cpumask_var(rd
->span
);
7007 static void rq_attach_root(struct rq
*rq
, struct root_domain
*rd
)
7009 unsigned long flags
;
7011 spin_lock_irqsave(&rq
->lock
, flags
);
7014 struct root_domain
*old_rd
= rq
->rd
;
7016 if (cpumask_test_cpu(rq
->cpu
, old_rd
->online
))
7019 cpumask_clear_cpu(rq
->cpu
, old_rd
->span
);
7021 if (atomic_dec_and_test(&old_rd
->refcount
))
7022 free_rootdomain(old_rd
);
7025 atomic_inc(&rd
->refcount
);
7028 cpumask_set_cpu(rq
->cpu
, rd
->span
);
7029 if (cpumask_test_cpu(rq
->cpu
, cpu_online_mask
))
7032 spin_unlock_irqrestore(&rq
->lock
, flags
);
7035 static int __init_refok
init_rootdomain(struct root_domain
*rd
, bool bootmem
)
7037 memset(rd
, 0, sizeof(*rd
));
7040 alloc_bootmem_cpumask_var(&def_root_domain
.span
);
7041 alloc_bootmem_cpumask_var(&def_root_domain
.online
);
7042 alloc_bootmem_cpumask_var(&def_root_domain
.rto_mask
);
7043 cpupri_init(&rd
->cpupri
, true);
7047 if (!alloc_cpumask_var(&rd
->span
, GFP_KERNEL
))
7049 if (!alloc_cpumask_var(&rd
->online
, GFP_KERNEL
))
7051 if (!alloc_cpumask_var(&rd
->rto_mask
, GFP_KERNEL
))
7054 if (cpupri_init(&rd
->cpupri
, false) != 0)
7059 free_cpumask_var(rd
->rto_mask
);
7061 free_cpumask_var(rd
->online
);
7063 free_cpumask_var(rd
->span
);
7068 static void init_defrootdomain(void)
7070 init_rootdomain(&def_root_domain
, true);
7072 atomic_set(&def_root_domain
.refcount
, 1);
7075 static struct root_domain
*alloc_rootdomain(void)
7077 struct root_domain
*rd
;
7079 rd
= kmalloc(sizeof(*rd
), GFP_KERNEL
);
7083 if (init_rootdomain(rd
, false) != 0) {
7092 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
7093 * hold the hotplug lock.
7096 cpu_attach_domain(struct sched_domain
*sd
, struct root_domain
*rd
, int cpu
)
7098 struct rq
*rq
= cpu_rq(cpu
);
7099 struct sched_domain
*tmp
;
7101 /* Remove the sched domains which do not contribute to scheduling. */
7102 for (tmp
= sd
; tmp
; ) {
7103 struct sched_domain
*parent
= tmp
->parent
;
7107 if (sd_parent_degenerate(tmp
, parent
)) {
7108 tmp
->parent
= parent
->parent
;
7110 parent
->parent
->child
= tmp
;
7115 if (sd
&& sd_degenerate(sd
)) {
7121 sched_domain_debug(sd
, cpu
);
7123 rq_attach_root(rq
, rd
);
7124 rcu_assign_pointer(rq
->sd
, sd
);
7127 /* cpus with isolated domains */
7128 static cpumask_var_t cpu_isolated_map
;
7130 /* Setup the mask of cpus configured for isolated domains */
7131 static int __init
isolated_cpu_setup(char *str
)
7133 cpulist_parse(str
, cpu_isolated_map
);
7137 __setup("isolcpus=", isolated_cpu_setup
);
7140 * init_sched_build_groups takes the cpumask we wish to span, and a pointer
7141 * to a function which identifies what group(along with sched group) a CPU
7142 * belongs to. The return value of group_fn must be a >= 0 and < nr_cpu_ids
7143 * (due to the fact that we keep track of groups covered with a struct cpumask).
7145 * init_sched_build_groups will build a circular linked list of the groups
7146 * covered by the given span, and will set each group's ->cpumask correctly,
7147 * and ->cpu_power to 0.
7150 init_sched_build_groups(const struct cpumask
*span
,
7151 const struct cpumask
*cpu_map
,
7152 int (*group_fn
)(int cpu
, const struct cpumask
*cpu_map
,
7153 struct sched_group
**sg
,
7154 struct cpumask
*tmpmask
),
7155 struct cpumask
*covered
, struct cpumask
*tmpmask
)
7157 struct sched_group
*first
= NULL
, *last
= NULL
;
7160 cpumask_clear(covered
);
7162 for_each_cpu(i
, span
) {
7163 struct sched_group
*sg
;
7164 int group
= group_fn(i
, cpu_map
, &sg
, tmpmask
);
7167 if (cpumask_test_cpu(i
, covered
))
7170 cpumask_clear(sched_group_cpus(sg
));
7171 sg
->__cpu_power
= 0;
7173 for_each_cpu(j
, span
) {
7174 if (group_fn(j
, cpu_map
, NULL
, tmpmask
) != group
)
7177 cpumask_set_cpu(j
, covered
);
7178 cpumask_set_cpu(j
, sched_group_cpus(sg
));
7189 #define SD_NODES_PER_DOMAIN 16
7194 * find_next_best_node - find the next node to include in a sched_domain
7195 * @node: node whose sched_domain we're building
7196 * @used_nodes: nodes already in the sched_domain
7198 * Find the next node to include in a given scheduling domain. Simply
7199 * finds the closest node not already in the @used_nodes map.
7201 * Should use nodemask_t.
7203 static int find_next_best_node(int node
, nodemask_t
*used_nodes
)
7205 int i
, n
, val
, min_val
, best_node
= 0;
7209 for (i
= 0; i
< nr_node_ids
; i
++) {
7210 /* Start at @node */
7211 n
= (node
+ i
) % nr_node_ids
;
7213 if (!nr_cpus_node(n
))
7216 /* Skip already used nodes */
7217 if (node_isset(n
, *used_nodes
))
7220 /* Simple min distance search */
7221 val
= node_distance(node
, n
);
7223 if (val
< min_val
) {
7229 node_set(best_node
, *used_nodes
);
7234 * sched_domain_node_span - get a cpumask for a node's sched_domain
7235 * @node: node whose cpumask we're constructing
7236 * @span: resulting cpumask
7238 * Given a node, construct a good cpumask for its sched_domain to span. It
7239 * should be one that prevents unnecessary balancing, but also spreads tasks
7242 static void sched_domain_node_span(int node
, struct cpumask
*span
)
7244 nodemask_t used_nodes
;
7247 cpumask_clear(span
);
7248 nodes_clear(used_nodes
);
7250 cpumask_or(span
, span
, cpumask_of_node(node
));
7251 node_set(node
, used_nodes
);
7253 for (i
= 1; i
< SD_NODES_PER_DOMAIN
; i
++) {
7254 int next_node
= find_next_best_node(node
, &used_nodes
);
7256 cpumask_or(span
, span
, cpumask_of_node(next_node
));
7259 #endif /* CONFIG_NUMA */
7261 int sched_smt_power_savings
= 0, sched_mc_power_savings
= 0;
7264 * The cpus mask in sched_group and sched_domain hangs off the end.
7265 * FIXME: use cpumask_var_t or dynamic percpu alloc to avoid wasting space
7266 * for nr_cpu_ids < CONFIG_NR_CPUS.
7268 struct static_sched_group
{
7269 struct sched_group sg
;
7270 DECLARE_BITMAP(cpus
, CONFIG_NR_CPUS
);
7273 struct static_sched_domain
{
7274 struct sched_domain sd
;
7275 DECLARE_BITMAP(span
, CONFIG_NR_CPUS
);
7279 * SMT sched-domains:
7281 #ifdef CONFIG_SCHED_SMT
7282 static DEFINE_PER_CPU(struct static_sched_domain
, cpu_domains
);
7283 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_cpus
);
7286 cpu_to_cpu_group(int cpu
, const struct cpumask
*cpu_map
,
7287 struct sched_group
**sg
, struct cpumask
*unused
)
7290 *sg
= &per_cpu(sched_group_cpus
, cpu
).sg
;
7293 #endif /* CONFIG_SCHED_SMT */
7296 * multi-core sched-domains:
7298 #ifdef CONFIG_SCHED_MC
7299 static DEFINE_PER_CPU(struct static_sched_domain
, core_domains
);
7300 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_core
);
7301 #endif /* CONFIG_SCHED_MC */
7303 #if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT)
7305 cpu_to_core_group(int cpu
, const struct cpumask
*cpu_map
,
7306 struct sched_group
**sg
, struct cpumask
*mask
)
7310 cpumask_and(mask
, &per_cpu(cpu_sibling_map
, cpu
), cpu_map
);
7311 group
= cpumask_first(mask
);
7313 *sg
= &per_cpu(sched_group_core
, group
).sg
;
7316 #elif defined(CONFIG_SCHED_MC)
7318 cpu_to_core_group(int cpu
, const struct cpumask
*cpu_map
,
7319 struct sched_group
**sg
, struct cpumask
*unused
)
7322 *sg
= &per_cpu(sched_group_core
, cpu
).sg
;
7327 static DEFINE_PER_CPU(struct static_sched_domain
, phys_domains
);
7328 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_phys
);
7331 cpu_to_phys_group(int cpu
, const struct cpumask
*cpu_map
,
7332 struct sched_group
**sg
, struct cpumask
*mask
)
7335 #ifdef CONFIG_SCHED_MC
7336 cpumask_and(mask
, cpu_coregroup_mask(cpu
), cpu_map
);
7337 group
= cpumask_first(mask
);
7338 #elif defined(CONFIG_SCHED_SMT)
7339 cpumask_and(mask
, &per_cpu(cpu_sibling_map
, cpu
), cpu_map
);
7340 group
= cpumask_first(mask
);
7345 *sg
= &per_cpu(sched_group_phys
, group
).sg
;
7351 * The init_sched_build_groups can't handle what we want to do with node
7352 * groups, so roll our own. Now each node has its own list of groups which
7353 * gets dynamically allocated.
7355 static DEFINE_PER_CPU(struct sched_domain
, node_domains
);
7356 static struct sched_group
***sched_group_nodes_bycpu
;
7358 static DEFINE_PER_CPU(struct sched_domain
, allnodes_domains
);
7359 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_allnodes
);
7361 static int cpu_to_allnodes_group(int cpu
, const struct cpumask
*cpu_map
,
7362 struct sched_group
**sg
,
7363 struct cpumask
*nodemask
)
7367 cpumask_and(nodemask
, cpumask_of_node(cpu_to_node(cpu
)), cpu_map
);
7368 group
= cpumask_first(nodemask
);
7371 *sg
= &per_cpu(sched_group_allnodes
, group
).sg
;
7375 static void init_numa_sched_groups_power(struct sched_group
*group_head
)
7377 struct sched_group
*sg
= group_head
;
7383 for_each_cpu(j
, sched_group_cpus(sg
)) {
7384 struct sched_domain
*sd
;
7386 sd
= &per_cpu(phys_domains
, j
).sd
;
7387 if (j
!= cpumask_first(sched_group_cpus(sd
->groups
))) {
7389 * Only add "power" once for each
7395 sg_inc_cpu_power(sg
, sd
->groups
->__cpu_power
);
7398 } while (sg
!= group_head
);
7400 #endif /* CONFIG_NUMA */
7403 /* Free memory allocated for various sched_group structures */
7404 static void free_sched_groups(const struct cpumask
*cpu_map
,
7405 struct cpumask
*nodemask
)
7409 for_each_cpu(cpu
, cpu_map
) {
7410 struct sched_group
**sched_group_nodes
7411 = sched_group_nodes_bycpu
[cpu
];
7413 if (!sched_group_nodes
)
7416 for (i
= 0; i
< nr_node_ids
; i
++) {
7417 struct sched_group
*oldsg
, *sg
= sched_group_nodes
[i
];
7419 cpumask_and(nodemask
, cpumask_of_node(i
), cpu_map
);
7420 if (cpumask_empty(nodemask
))
7430 if (oldsg
!= sched_group_nodes
[i
])
7433 kfree(sched_group_nodes
);
7434 sched_group_nodes_bycpu
[cpu
] = NULL
;
7437 #else /* !CONFIG_NUMA */
7438 static void free_sched_groups(const struct cpumask
*cpu_map
,
7439 struct cpumask
*nodemask
)
7442 #endif /* CONFIG_NUMA */
7445 * Initialize sched groups cpu_power.
7447 * cpu_power indicates the capacity of sched group, which is used while
7448 * distributing the load between different sched groups in a sched domain.
7449 * Typically cpu_power for all the groups in a sched domain will be same unless
7450 * there are asymmetries in the topology. If there are asymmetries, group
7451 * having more cpu_power will pickup more load compared to the group having
7454 * cpu_power will be a multiple of SCHED_LOAD_SCALE. This multiple represents
7455 * the maximum number of tasks a group can handle in the presence of other idle
7456 * or lightly loaded groups in the same sched domain.
7458 static void init_sched_groups_power(int cpu
, struct sched_domain
*sd
)
7460 struct sched_domain
*child
;
7461 struct sched_group
*group
;
7463 WARN_ON(!sd
|| !sd
->groups
);
7465 if (cpu
!= cpumask_first(sched_group_cpus(sd
->groups
)))
7470 sd
->groups
->__cpu_power
= 0;
7473 * For perf policy, if the groups in child domain share resources
7474 * (for example cores sharing some portions of the cache hierarchy
7475 * or SMT), then set this domain groups cpu_power such that each group
7476 * can handle only one task, when there are other idle groups in the
7477 * same sched domain.
7479 if (!child
|| (!(sd
->flags
& SD_POWERSAVINGS_BALANCE
) &&
7481 (SD_SHARE_CPUPOWER
| SD_SHARE_PKG_RESOURCES
)))) {
7482 sg_inc_cpu_power(sd
->groups
, SCHED_LOAD_SCALE
);
7487 * add cpu_power of each child group to this groups cpu_power
7489 group
= child
->groups
;
7491 sg_inc_cpu_power(sd
->groups
, group
->__cpu_power
);
7492 group
= group
->next
;
7493 } while (group
!= child
->groups
);
7497 * Initializers for schedule domains
7498 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
7501 #ifdef CONFIG_SCHED_DEBUG
7502 # define SD_INIT_NAME(sd, type) sd->name = #type
7504 # define SD_INIT_NAME(sd, type) do { } while (0)
7507 #define SD_INIT(sd, type) sd_init_##type(sd)
7509 #define SD_INIT_FUNC(type) \
7510 static noinline void sd_init_##type(struct sched_domain *sd) \
7512 memset(sd, 0, sizeof(*sd)); \
7513 *sd = SD_##type##_INIT; \
7514 sd->level = SD_LV_##type; \
7515 SD_INIT_NAME(sd, type); \
7520 SD_INIT_FUNC(ALLNODES
)
7523 #ifdef CONFIG_SCHED_SMT
7524 SD_INIT_FUNC(SIBLING
)
7526 #ifdef CONFIG_SCHED_MC
7530 static int default_relax_domain_level
= -1;
7532 static int __init
setup_relax_domain_level(char *str
)
7536 val
= simple_strtoul(str
, NULL
, 0);
7537 if (val
< SD_LV_MAX
)
7538 default_relax_domain_level
= val
;
7542 __setup("relax_domain_level=", setup_relax_domain_level
);
7544 static void set_domain_attribute(struct sched_domain
*sd
,
7545 struct sched_domain_attr
*attr
)
7549 if (!attr
|| attr
->relax_domain_level
< 0) {
7550 if (default_relax_domain_level
< 0)
7553 request
= default_relax_domain_level
;
7555 request
= attr
->relax_domain_level
;
7556 if (request
< sd
->level
) {
7557 /* turn off idle balance on this domain */
7558 sd
->flags
&= ~(SD_WAKE_IDLE
|SD_BALANCE_NEWIDLE
);
7560 /* turn on idle balance on this domain */
7561 sd
->flags
|= (SD_WAKE_IDLE_FAR
|SD_BALANCE_NEWIDLE
);
7566 * Build sched domains for a given set of cpus and attach the sched domains
7567 * to the individual cpus
7569 static int __build_sched_domains(const struct cpumask
*cpu_map
,
7570 struct sched_domain_attr
*attr
)
7572 int i
, err
= -ENOMEM
;
7573 struct root_domain
*rd
;
7574 cpumask_var_t nodemask
, this_sibling_map
, this_core_map
, send_covered
,
7577 cpumask_var_t domainspan
, covered
, notcovered
;
7578 struct sched_group
**sched_group_nodes
= NULL
;
7579 int sd_allnodes
= 0;
7581 if (!alloc_cpumask_var(&domainspan
, GFP_KERNEL
))
7583 if (!alloc_cpumask_var(&covered
, GFP_KERNEL
))
7584 goto free_domainspan
;
7585 if (!alloc_cpumask_var(¬covered
, GFP_KERNEL
))
7589 if (!alloc_cpumask_var(&nodemask
, GFP_KERNEL
))
7590 goto free_notcovered
;
7591 if (!alloc_cpumask_var(&this_sibling_map
, GFP_KERNEL
))
7593 if (!alloc_cpumask_var(&this_core_map
, GFP_KERNEL
))
7594 goto free_this_sibling_map
;
7595 if (!alloc_cpumask_var(&send_covered
, GFP_KERNEL
))
7596 goto free_this_core_map
;
7597 if (!alloc_cpumask_var(&tmpmask
, GFP_KERNEL
))
7598 goto free_send_covered
;
7602 * Allocate the per-node list of sched groups
7604 sched_group_nodes
= kcalloc(nr_node_ids
, sizeof(struct sched_group
*),
7606 if (!sched_group_nodes
) {
7607 printk(KERN_WARNING
"Can not alloc sched group node list\n");
7612 rd
= alloc_rootdomain();
7614 printk(KERN_WARNING
"Cannot alloc root domain\n");
7615 goto free_sched_groups
;
7619 sched_group_nodes_bycpu
[cpumask_first(cpu_map
)] = sched_group_nodes
;
7623 * Set up domains for cpus specified by the cpu_map.
7625 for_each_cpu(i
, cpu_map
) {
7626 struct sched_domain
*sd
= NULL
, *p
;
7628 cpumask_and(nodemask
, cpumask_of_node(cpu_to_node(i
)), cpu_map
);
7631 if (cpumask_weight(cpu_map
) >
7632 SD_NODES_PER_DOMAIN
*cpumask_weight(nodemask
)) {
7633 sd
= &per_cpu(allnodes_domains
, i
);
7634 SD_INIT(sd
, ALLNODES
);
7635 set_domain_attribute(sd
, attr
);
7636 cpumask_copy(sched_domain_span(sd
), cpu_map
);
7637 cpu_to_allnodes_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
7643 sd
= &per_cpu(node_domains
, i
);
7645 set_domain_attribute(sd
, attr
);
7646 sched_domain_node_span(cpu_to_node(i
), sched_domain_span(sd
));
7650 cpumask_and(sched_domain_span(sd
),
7651 sched_domain_span(sd
), cpu_map
);
7655 sd
= &per_cpu(phys_domains
, i
).sd
;
7657 set_domain_attribute(sd
, attr
);
7658 cpumask_copy(sched_domain_span(sd
), nodemask
);
7662 cpu_to_phys_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
7664 #ifdef CONFIG_SCHED_MC
7666 sd
= &per_cpu(core_domains
, i
).sd
;
7668 set_domain_attribute(sd
, attr
);
7669 cpumask_and(sched_domain_span(sd
), cpu_map
,
7670 cpu_coregroup_mask(i
));
7673 cpu_to_core_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
7676 #ifdef CONFIG_SCHED_SMT
7678 sd
= &per_cpu(cpu_domains
, i
).sd
;
7679 SD_INIT(sd
, SIBLING
);
7680 set_domain_attribute(sd
, attr
);
7681 cpumask_and(sched_domain_span(sd
),
7682 &per_cpu(cpu_sibling_map
, i
), cpu_map
);
7685 cpu_to_cpu_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
7689 #ifdef CONFIG_SCHED_SMT
7690 /* Set up CPU (sibling) groups */
7691 for_each_cpu(i
, cpu_map
) {
7692 cpumask_and(this_sibling_map
,
7693 &per_cpu(cpu_sibling_map
, i
), cpu_map
);
7694 if (i
!= cpumask_first(this_sibling_map
))
7697 init_sched_build_groups(this_sibling_map
, cpu_map
,
7699 send_covered
, tmpmask
);
7703 #ifdef CONFIG_SCHED_MC
7704 /* Set up multi-core groups */
7705 for_each_cpu(i
, cpu_map
) {
7706 cpumask_and(this_core_map
, cpu_coregroup_mask(i
), cpu_map
);
7707 if (i
!= cpumask_first(this_core_map
))
7710 init_sched_build_groups(this_core_map
, cpu_map
,
7712 send_covered
, tmpmask
);
7716 /* Set up physical groups */
7717 for (i
= 0; i
< nr_node_ids
; i
++) {
7718 cpumask_and(nodemask
, cpumask_of_node(i
), cpu_map
);
7719 if (cpumask_empty(nodemask
))
7722 init_sched_build_groups(nodemask
, cpu_map
,
7724 send_covered
, tmpmask
);
7728 /* Set up node groups */
7730 init_sched_build_groups(cpu_map
, cpu_map
,
7731 &cpu_to_allnodes_group
,
7732 send_covered
, tmpmask
);
7735 for (i
= 0; i
< nr_node_ids
; i
++) {
7736 /* Set up node groups */
7737 struct sched_group
*sg
, *prev
;
7740 cpumask_clear(covered
);
7741 cpumask_and(nodemask
, cpumask_of_node(i
), cpu_map
);
7742 if (cpumask_empty(nodemask
)) {
7743 sched_group_nodes
[i
] = NULL
;
7747 sched_domain_node_span(i
, domainspan
);
7748 cpumask_and(domainspan
, domainspan
, cpu_map
);
7750 sg
= kmalloc_node(sizeof(struct sched_group
) + cpumask_size(),
7753 printk(KERN_WARNING
"Can not alloc domain group for "
7757 sched_group_nodes
[i
] = sg
;
7758 for_each_cpu(j
, nodemask
) {
7759 struct sched_domain
*sd
;
7761 sd
= &per_cpu(node_domains
, j
);
7764 sg
->__cpu_power
= 0;
7765 cpumask_copy(sched_group_cpus(sg
), nodemask
);
7767 cpumask_or(covered
, covered
, nodemask
);
7770 for (j
= 0; j
< nr_node_ids
; j
++) {
7771 int n
= (i
+ j
) % nr_node_ids
;
7773 cpumask_complement(notcovered
, covered
);
7774 cpumask_and(tmpmask
, notcovered
, cpu_map
);
7775 cpumask_and(tmpmask
, tmpmask
, domainspan
);
7776 if (cpumask_empty(tmpmask
))
7779 cpumask_and(tmpmask
, tmpmask
, cpumask_of_node(n
));
7780 if (cpumask_empty(tmpmask
))
7783 sg
= kmalloc_node(sizeof(struct sched_group
) +
7788 "Can not alloc domain group for node %d\n", j
);
7791 sg
->__cpu_power
= 0;
7792 cpumask_copy(sched_group_cpus(sg
), tmpmask
);
7793 sg
->next
= prev
->next
;
7794 cpumask_or(covered
, covered
, tmpmask
);
7801 /* Calculate CPU power for physical packages and nodes */
7802 #ifdef CONFIG_SCHED_SMT
7803 for_each_cpu(i
, cpu_map
) {
7804 struct sched_domain
*sd
= &per_cpu(cpu_domains
, i
).sd
;
7806 init_sched_groups_power(i
, sd
);
7809 #ifdef CONFIG_SCHED_MC
7810 for_each_cpu(i
, cpu_map
) {
7811 struct sched_domain
*sd
= &per_cpu(core_domains
, i
).sd
;
7813 init_sched_groups_power(i
, sd
);
7817 for_each_cpu(i
, cpu_map
) {
7818 struct sched_domain
*sd
= &per_cpu(phys_domains
, i
).sd
;
7820 init_sched_groups_power(i
, sd
);
7824 for (i
= 0; i
< nr_node_ids
; i
++)
7825 init_numa_sched_groups_power(sched_group_nodes
[i
]);
7828 struct sched_group
*sg
;
7830 cpu_to_allnodes_group(cpumask_first(cpu_map
), cpu_map
, &sg
,
7832 init_numa_sched_groups_power(sg
);
7836 /* Attach the domains */
7837 for_each_cpu(i
, cpu_map
) {
7838 struct sched_domain
*sd
;
7839 #ifdef CONFIG_SCHED_SMT
7840 sd
= &per_cpu(cpu_domains
, i
).sd
;
7841 #elif defined(CONFIG_SCHED_MC)
7842 sd
= &per_cpu(core_domains
, i
).sd
;
7844 sd
= &per_cpu(phys_domains
, i
).sd
;
7846 cpu_attach_domain(sd
, rd
, i
);
7852 free_cpumask_var(tmpmask
);
7854 free_cpumask_var(send_covered
);
7856 free_cpumask_var(this_core_map
);
7857 free_this_sibling_map
:
7858 free_cpumask_var(this_sibling_map
);
7860 free_cpumask_var(nodemask
);
7863 free_cpumask_var(notcovered
);
7865 free_cpumask_var(covered
);
7867 free_cpumask_var(domainspan
);
7874 kfree(sched_group_nodes
);
7880 free_sched_groups(cpu_map
, tmpmask
);
7881 free_rootdomain(rd
);
7886 static int build_sched_domains(const struct cpumask
*cpu_map
)
7888 return __build_sched_domains(cpu_map
, NULL
);
7891 static struct cpumask
*doms_cur
; /* current sched domains */
7892 static int ndoms_cur
; /* number of sched domains in 'doms_cur' */
7893 static struct sched_domain_attr
*dattr_cur
;
7894 /* attribues of custom domains in 'doms_cur' */
7897 * Special case: If a kmalloc of a doms_cur partition (array of
7898 * cpumask) fails, then fallback to a single sched domain,
7899 * as determined by the single cpumask fallback_doms.
7901 static cpumask_var_t fallback_doms
;
7904 * arch_update_cpu_topology lets virtualized architectures update the
7905 * cpu core maps. It is supposed to return 1 if the topology changed
7906 * or 0 if it stayed the same.
7908 int __attribute__((weak
)) arch_update_cpu_topology(void)
7914 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
7915 * For now this just excludes isolated cpus, but could be used to
7916 * exclude other special cases in the future.
7918 static int arch_init_sched_domains(const struct cpumask
*cpu_map
)
7922 arch_update_cpu_topology();
7924 doms_cur
= kmalloc(cpumask_size(), GFP_KERNEL
);
7926 doms_cur
= fallback_doms
;
7927 cpumask_andnot(doms_cur
, cpu_map
, cpu_isolated_map
);
7929 err
= build_sched_domains(doms_cur
);
7930 register_sched_domain_sysctl();
7935 static void arch_destroy_sched_domains(const struct cpumask
*cpu_map
,
7936 struct cpumask
*tmpmask
)
7938 free_sched_groups(cpu_map
, tmpmask
);
7942 * Detach sched domains from a group of cpus specified in cpu_map
7943 * These cpus will now be attached to the NULL domain
7945 static void detach_destroy_domains(const struct cpumask
*cpu_map
)
7947 /* Save because hotplug lock held. */
7948 static DECLARE_BITMAP(tmpmask
, CONFIG_NR_CPUS
);
7951 for_each_cpu(i
, cpu_map
)
7952 cpu_attach_domain(NULL
, &def_root_domain
, i
);
7953 synchronize_sched();
7954 arch_destroy_sched_domains(cpu_map
, to_cpumask(tmpmask
));
7957 /* handle null as "default" */
7958 static int dattrs_equal(struct sched_domain_attr
*cur
, int idx_cur
,
7959 struct sched_domain_attr
*new, int idx_new
)
7961 struct sched_domain_attr tmp
;
7968 return !memcmp(cur
? (cur
+ idx_cur
) : &tmp
,
7969 new ? (new + idx_new
) : &tmp
,
7970 sizeof(struct sched_domain_attr
));
7974 * Partition sched domains as specified by the 'ndoms_new'
7975 * cpumasks in the array doms_new[] of cpumasks. This compares
7976 * doms_new[] to the current sched domain partitioning, doms_cur[].
7977 * It destroys each deleted domain and builds each new domain.
7979 * 'doms_new' is an array of cpumask's of length 'ndoms_new'.
7980 * The masks don't intersect (don't overlap.) We should setup one
7981 * sched domain for each mask. CPUs not in any of the cpumasks will
7982 * not be load balanced. If the same cpumask appears both in the
7983 * current 'doms_cur' domains and in the new 'doms_new', we can leave
7986 * The passed in 'doms_new' should be kmalloc'd. This routine takes
7987 * ownership of it and will kfree it when done with it. If the caller
7988 * failed the kmalloc call, then it can pass in doms_new == NULL &&
7989 * ndoms_new == 1, and partition_sched_domains() will fallback to
7990 * the single partition 'fallback_doms', it also forces the domains
7993 * If doms_new == NULL it will be replaced with cpu_online_mask.
7994 * ndoms_new == 0 is a special case for destroying existing domains,
7995 * and it will not create the default domain.
7997 * Call with hotplug lock held
7999 /* FIXME: Change to struct cpumask *doms_new[] */
8000 void partition_sched_domains(int ndoms_new
, struct cpumask
*doms_new
,
8001 struct sched_domain_attr
*dattr_new
)
8006 mutex_lock(&sched_domains_mutex
);
8008 /* always unregister in case we don't destroy any domains */
8009 unregister_sched_domain_sysctl();
8011 /* Let architecture update cpu core mappings. */
8012 new_topology
= arch_update_cpu_topology();
8014 n
= doms_new
? ndoms_new
: 0;
8016 /* Destroy deleted domains */
8017 for (i
= 0; i
< ndoms_cur
; i
++) {
8018 for (j
= 0; j
< n
&& !new_topology
; j
++) {
8019 if (cpumask_equal(&doms_cur
[i
], &doms_new
[j
])
8020 && dattrs_equal(dattr_cur
, i
, dattr_new
, j
))
8023 /* no match - a current sched domain not in new doms_new[] */
8024 detach_destroy_domains(doms_cur
+ i
);
8029 if (doms_new
== NULL
) {
8031 doms_new
= fallback_doms
;
8032 cpumask_andnot(&doms_new
[0], cpu_online_mask
, cpu_isolated_map
);
8033 WARN_ON_ONCE(dattr_new
);
8036 /* Build new domains */
8037 for (i
= 0; i
< ndoms_new
; i
++) {
8038 for (j
= 0; j
< ndoms_cur
&& !new_topology
; j
++) {
8039 if (cpumask_equal(&doms_new
[i
], &doms_cur
[j
])
8040 && dattrs_equal(dattr_new
, i
, dattr_cur
, j
))
8043 /* no match - add a new doms_new */
8044 __build_sched_domains(doms_new
+ i
,
8045 dattr_new
? dattr_new
+ i
: NULL
);
8050 /* Remember the new sched domains */
8051 if (doms_cur
!= fallback_doms
)
8053 kfree(dattr_cur
); /* kfree(NULL) is safe */
8054 doms_cur
= doms_new
;
8055 dattr_cur
= dattr_new
;
8056 ndoms_cur
= ndoms_new
;
8058 register_sched_domain_sysctl();
8060 mutex_unlock(&sched_domains_mutex
);
8063 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
8064 static void arch_reinit_sched_domains(void)
8068 /* Destroy domains first to force the rebuild */
8069 partition_sched_domains(0, NULL
, NULL
);
8071 rebuild_sched_domains();
8075 static ssize_t
sched_power_savings_store(const char *buf
, size_t count
, int smt
)
8077 unsigned int level
= 0;
8079 if (sscanf(buf
, "%u", &level
) != 1)
8083 * level is always be positive so don't check for
8084 * level < POWERSAVINGS_BALANCE_NONE which is 0
8085 * What happens on 0 or 1 byte write,
8086 * need to check for count as well?
8089 if (level
>= MAX_POWERSAVINGS_BALANCE_LEVELS
)
8093 sched_smt_power_savings
= level
;
8095 sched_mc_power_savings
= level
;
8097 arch_reinit_sched_domains();
8102 #ifdef CONFIG_SCHED_MC
8103 static ssize_t
sched_mc_power_savings_show(struct sysdev_class
*class,
8106 return sprintf(page
, "%u\n", sched_mc_power_savings
);
8108 static ssize_t
sched_mc_power_savings_store(struct sysdev_class
*class,
8109 const char *buf
, size_t count
)
8111 return sched_power_savings_store(buf
, count
, 0);
8113 static SYSDEV_CLASS_ATTR(sched_mc_power_savings
, 0644,
8114 sched_mc_power_savings_show
,
8115 sched_mc_power_savings_store
);
8118 #ifdef CONFIG_SCHED_SMT
8119 static ssize_t
sched_smt_power_savings_show(struct sysdev_class
*dev
,
8122 return sprintf(page
, "%u\n", sched_smt_power_savings
);
8124 static ssize_t
sched_smt_power_savings_store(struct sysdev_class
*dev
,
8125 const char *buf
, size_t count
)
8127 return sched_power_savings_store(buf
, count
, 1);
8129 static SYSDEV_CLASS_ATTR(sched_smt_power_savings
, 0644,
8130 sched_smt_power_savings_show
,
8131 sched_smt_power_savings_store
);
8134 int __init
sched_create_sysfs_power_savings_entries(struct sysdev_class
*cls
)
8138 #ifdef CONFIG_SCHED_SMT
8140 err
= sysfs_create_file(&cls
->kset
.kobj
,
8141 &attr_sched_smt_power_savings
.attr
);
8143 #ifdef CONFIG_SCHED_MC
8144 if (!err
&& mc_capable())
8145 err
= sysfs_create_file(&cls
->kset
.kobj
,
8146 &attr_sched_mc_power_savings
.attr
);
8150 #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
8152 #ifndef CONFIG_CPUSETS
8154 * Add online and remove offline CPUs from the scheduler domains.
8155 * When cpusets are enabled they take over this function.
8157 static int update_sched_domains(struct notifier_block
*nfb
,
8158 unsigned long action
, void *hcpu
)
8162 case CPU_ONLINE_FROZEN
:
8164 case CPU_DEAD_FROZEN
:
8165 partition_sched_domains(1, NULL
, NULL
);
8174 static int update_runtime(struct notifier_block
*nfb
,
8175 unsigned long action
, void *hcpu
)
8177 int cpu
= (int)(long)hcpu
;
8180 case CPU_DOWN_PREPARE
:
8181 case CPU_DOWN_PREPARE_FROZEN
:
8182 disable_runtime(cpu_rq(cpu
));
8185 case CPU_DOWN_FAILED
:
8186 case CPU_DOWN_FAILED_FROZEN
:
8188 case CPU_ONLINE_FROZEN
:
8189 enable_runtime(cpu_rq(cpu
));
8197 void __init
sched_init_smp(void)
8199 cpumask_var_t non_isolated_cpus
;
8201 alloc_cpumask_var(&non_isolated_cpus
, GFP_KERNEL
);
8203 #if defined(CONFIG_NUMA)
8204 sched_group_nodes_bycpu
= kzalloc(nr_cpu_ids
* sizeof(void **),
8206 BUG_ON(sched_group_nodes_bycpu
== NULL
);
8209 mutex_lock(&sched_domains_mutex
);
8210 arch_init_sched_domains(cpu_online_mask
);
8211 cpumask_andnot(non_isolated_cpus
, cpu_possible_mask
, cpu_isolated_map
);
8212 if (cpumask_empty(non_isolated_cpus
))
8213 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus
);
8214 mutex_unlock(&sched_domains_mutex
);
8217 #ifndef CONFIG_CPUSETS
8218 /* XXX: Theoretical race here - CPU may be hotplugged now */
8219 hotcpu_notifier(update_sched_domains
, 0);
8222 /* RT runtime code needs to handle some hotplug events */
8223 hotcpu_notifier(update_runtime
, 0);
8227 /* Move init over to a non-isolated CPU */
8228 if (set_cpus_allowed_ptr(current
, non_isolated_cpus
) < 0)
8230 sched_init_granularity();
8231 free_cpumask_var(non_isolated_cpus
);
8233 alloc_cpumask_var(&fallback_doms
, GFP_KERNEL
);
8234 init_sched_rt_class();
8237 void __init
sched_init_smp(void)
8239 sched_init_granularity();
8241 #endif /* CONFIG_SMP */
8243 int in_sched_functions(unsigned long addr
)
8245 return in_lock_functions(addr
) ||
8246 (addr
>= (unsigned long)__sched_text_start
8247 && addr
< (unsigned long)__sched_text_end
);
8250 static void init_cfs_rq(struct cfs_rq
*cfs_rq
, struct rq
*rq
)
8252 cfs_rq
->tasks_timeline
= RB_ROOT
;
8253 INIT_LIST_HEAD(&cfs_rq
->tasks
);
8254 #ifdef CONFIG_FAIR_GROUP_SCHED
8257 cfs_rq
->min_vruntime
= (u64
)(-(1LL << 20));
8260 static void init_rt_rq(struct rt_rq
*rt_rq
, struct rq
*rq
)
8262 struct rt_prio_array
*array
;
8265 array
= &rt_rq
->active
;
8266 for (i
= 0; i
< MAX_RT_PRIO
; i
++) {
8267 INIT_LIST_HEAD(array
->queue
+ i
);
8268 __clear_bit(i
, array
->bitmap
);
8270 /* delimiter for bitsearch: */
8271 __set_bit(MAX_RT_PRIO
, array
->bitmap
);
8273 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
8274 rt_rq
->highest_prio
= MAX_RT_PRIO
;
8277 rt_rq
->rt_nr_migratory
= 0;
8278 rt_rq
->overloaded
= 0;
8282 rt_rq
->rt_throttled
= 0;
8283 rt_rq
->rt_runtime
= 0;
8284 spin_lock_init(&rt_rq
->rt_runtime_lock
);
8286 #ifdef CONFIG_RT_GROUP_SCHED
8287 rt_rq
->rt_nr_boosted
= 0;
8292 #ifdef CONFIG_FAIR_GROUP_SCHED
8293 static void init_tg_cfs_entry(struct task_group
*tg
, struct cfs_rq
*cfs_rq
,
8294 struct sched_entity
*se
, int cpu
, int add
,
8295 struct sched_entity
*parent
)
8297 struct rq
*rq
= cpu_rq(cpu
);
8298 tg
->cfs_rq
[cpu
] = cfs_rq
;
8299 init_cfs_rq(cfs_rq
, rq
);
8302 list_add(&cfs_rq
->leaf_cfs_rq_list
, &rq
->leaf_cfs_rq_list
);
8305 /* se could be NULL for init_task_group */
8310 se
->cfs_rq
= &rq
->cfs
;
8312 se
->cfs_rq
= parent
->my_q
;
8315 se
->load
.weight
= tg
->shares
;
8316 se
->load
.inv_weight
= 0;
8317 se
->parent
= parent
;
8321 #ifdef CONFIG_RT_GROUP_SCHED
8322 static void init_tg_rt_entry(struct task_group
*tg
, struct rt_rq
*rt_rq
,
8323 struct sched_rt_entity
*rt_se
, int cpu
, int add
,
8324 struct sched_rt_entity
*parent
)
8326 struct rq
*rq
= cpu_rq(cpu
);
8328 tg
->rt_rq
[cpu
] = rt_rq
;
8329 init_rt_rq(rt_rq
, rq
);
8331 rt_rq
->rt_se
= rt_se
;
8332 rt_rq
->rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
8334 list_add(&rt_rq
->leaf_rt_rq_list
, &rq
->leaf_rt_rq_list
);
8336 tg
->rt_se
[cpu
] = rt_se
;
8341 rt_se
->rt_rq
= &rq
->rt
;
8343 rt_se
->rt_rq
= parent
->my_q
;
8345 rt_se
->my_q
= rt_rq
;
8346 rt_se
->parent
= parent
;
8347 INIT_LIST_HEAD(&rt_se
->run_list
);
8351 void __init
sched_init(void)
8354 unsigned long alloc_size
= 0, ptr
;
8356 #ifdef CONFIG_FAIR_GROUP_SCHED
8357 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
8359 #ifdef CONFIG_RT_GROUP_SCHED
8360 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
8362 #ifdef CONFIG_USER_SCHED
8366 * As sched_init() is called before page_alloc is setup,
8367 * we use alloc_bootmem().
8370 ptr
= (unsigned long)alloc_bootmem(alloc_size
);
8372 #ifdef CONFIG_FAIR_GROUP_SCHED
8373 init_task_group
.se
= (struct sched_entity
**)ptr
;
8374 ptr
+= nr_cpu_ids
* sizeof(void **);
8376 init_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
8377 ptr
+= nr_cpu_ids
* sizeof(void **);
8379 #ifdef CONFIG_USER_SCHED
8380 root_task_group
.se
= (struct sched_entity
**)ptr
;
8381 ptr
+= nr_cpu_ids
* sizeof(void **);
8383 root_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
8384 ptr
+= nr_cpu_ids
* sizeof(void **);
8385 #endif /* CONFIG_USER_SCHED */
8386 #endif /* CONFIG_FAIR_GROUP_SCHED */
8387 #ifdef CONFIG_RT_GROUP_SCHED
8388 init_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
8389 ptr
+= nr_cpu_ids
* sizeof(void **);
8391 init_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
8392 ptr
+= nr_cpu_ids
* sizeof(void **);
8394 #ifdef CONFIG_USER_SCHED
8395 root_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
8396 ptr
+= nr_cpu_ids
* sizeof(void **);
8398 root_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
8399 ptr
+= nr_cpu_ids
* sizeof(void **);
8400 #endif /* CONFIG_USER_SCHED */
8401 #endif /* CONFIG_RT_GROUP_SCHED */
8405 init_defrootdomain();
8408 init_rt_bandwidth(&def_rt_bandwidth
,
8409 global_rt_period(), global_rt_runtime());
8411 #ifdef CONFIG_RT_GROUP_SCHED
8412 init_rt_bandwidth(&init_task_group
.rt_bandwidth
,
8413 global_rt_period(), global_rt_runtime());
8414 #ifdef CONFIG_USER_SCHED
8415 init_rt_bandwidth(&root_task_group
.rt_bandwidth
,
8416 global_rt_period(), RUNTIME_INF
);
8417 #endif /* CONFIG_USER_SCHED */
8418 #endif /* CONFIG_RT_GROUP_SCHED */
8420 #ifdef CONFIG_GROUP_SCHED
8421 list_add(&init_task_group
.list
, &task_groups
);
8422 INIT_LIST_HEAD(&init_task_group
.children
);
8424 #ifdef CONFIG_USER_SCHED
8425 INIT_LIST_HEAD(&root_task_group
.children
);
8426 init_task_group
.parent
= &root_task_group
;
8427 list_add(&init_task_group
.siblings
, &root_task_group
.children
);
8428 #endif /* CONFIG_USER_SCHED */
8429 #endif /* CONFIG_GROUP_SCHED */
8431 for_each_possible_cpu(i
) {
8435 spin_lock_init(&rq
->lock
);
8437 init_cfs_rq(&rq
->cfs
, rq
);
8438 init_rt_rq(&rq
->rt
, rq
);
8439 #ifdef CONFIG_FAIR_GROUP_SCHED
8440 init_task_group
.shares
= init_task_group_load
;
8441 INIT_LIST_HEAD(&rq
->leaf_cfs_rq_list
);
8442 #ifdef CONFIG_CGROUP_SCHED
8444 * How much cpu bandwidth does init_task_group get?
8446 * In case of task-groups formed thr' the cgroup filesystem, it
8447 * gets 100% of the cpu resources in the system. This overall
8448 * system cpu resource is divided among the tasks of
8449 * init_task_group and its child task-groups in a fair manner,
8450 * based on each entity's (task or task-group's) weight
8451 * (se->load.weight).
8453 * In other words, if init_task_group has 10 tasks of weight
8454 * 1024) and two child groups A0 and A1 (of weight 1024 each),
8455 * then A0's share of the cpu resource is:
8457 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
8459 * We achieve this by letting init_task_group's tasks sit
8460 * directly in rq->cfs (i.e init_task_group->se[] = NULL).
8462 init_tg_cfs_entry(&init_task_group
, &rq
->cfs
, NULL
, i
, 1, NULL
);
8463 #elif defined CONFIG_USER_SCHED
8464 root_task_group
.shares
= NICE_0_LOAD
;
8465 init_tg_cfs_entry(&root_task_group
, &rq
->cfs
, NULL
, i
, 0, NULL
);
8467 * In case of task-groups formed thr' the user id of tasks,
8468 * init_task_group represents tasks belonging to root user.
8469 * Hence it forms a sibling of all subsequent groups formed.
8470 * In this case, init_task_group gets only a fraction of overall
8471 * system cpu resource, based on the weight assigned to root
8472 * user's cpu share (INIT_TASK_GROUP_LOAD). This is accomplished
8473 * by letting tasks of init_task_group sit in a separate cfs_rq
8474 * (init_cfs_rq) and having one entity represent this group of
8475 * tasks in rq->cfs (i.e init_task_group->se[] != NULL).
8477 init_tg_cfs_entry(&init_task_group
,
8478 &per_cpu(init_cfs_rq
, i
),
8479 &per_cpu(init_sched_entity
, i
), i
, 1,
8480 root_task_group
.se
[i
]);
8483 #endif /* CONFIG_FAIR_GROUP_SCHED */
8485 rq
->rt
.rt_runtime
= def_rt_bandwidth
.rt_runtime
;
8486 #ifdef CONFIG_RT_GROUP_SCHED
8487 INIT_LIST_HEAD(&rq
->leaf_rt_rq_list
);
8488 #ifdef CONFIG_CGROUP_SCHED
8489 init_tg_rt_entry(&init_task_group
, &rq
->rt
, NULL
, i
, 1, NULL
);
8490 #elif defined CONFIG_USER_SCHED
8491 init_tg_rt_entry(&root_task_group
, &rq
->rt
, NULL
, i
, 0, NULL
);
8492 init_tg_rt_entry(&init_task_group
,
8493 &per_cpu(init_rt_rq
, i
),
8494 &per_cpu(init_sched_rt_entity
, i
), i
, 1,
8495 root_task_group
.rt_se
[i
]);
8499 for (j
= 0; j
< CPU_LOAD_IDX_MAX
; j
++)
8500 rq
->cpu_load
[j
] = 0;
8504 rq
->active_balance
= 0;
8505 rq
->next_balance
= jiffies
;
8509 rq
->migration_thread
= NULL
;
8510 INIT_LIST_HEAD(&rq
->migration_queue
);
8511 rq_attach_root(rq
, &def_root_domain
);
8514 atomic_set(&rq
->nr_iowait
, 0);
8517 set_load_weight(&init_task
);
8519 #ifdef CONFIG_PREEMPT_NOTIFIERS
8520 INIT_HLIST_HEAD(&init_task
.preempt_notifiers
);
8524 open_softirq(SCHED_SOFTIRQ
, run_rebalance_domains
);
8527 #ifdef CONFIG_RT_MUTEXES
8528 plist_head_init(&init_task
.pi_waiters
, &init_task
.pi_lock
);
8532 * The boot idle thread does lazy MMU switching as well:
8534 atomic_inc(&init_mm
.mm_count
);
8535 enter_lazy_tlb(&init_mm
, current
);
8538 * Make us the idle thread. Technically, schedule() should not be
8539 * called from this thread, however somewhere below it might be,
8540 * but because we are the idle thread, we just pick up running again
8541 * when this runqueue becomes "idle".
8543 init_idle(current
, smp_processor_id());
8545 * During early bootup we pretend to be a normal task:
8547 current
->sched_class
= &fair_sched_class
;
8549 /* Allocate the nohz_cpu_mask if CONFIG_CPUMASK_OFFSTACK */
8550 alloc_bootmem_cpumask_var(&nohz_cpu_mask
);
8553 alloc_bootmem_cpumask_var(&nohz
.cpu_mask
);
8555 alloc_bootmem_cpumask_var(&cpu_isolated_map
);
8558 scheduler_running
= 1;
8561 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
8562 void __might_sleep(char *file
, int line
)
8565 static unsigned long prev_jiffy
; /* ratelimiting */
8567 if ((!in_atomic() && !irqs_disabled()) ||
8568 system_state
!= SYSTEM_RUNNING
|| oops_in_progress
)
8570 if (time_before(jiffies
, prev_jiffy
+ HZ
) && prev_jiffy
)
8572 prev_jiffy
= jiffies
;
8575 "BUG: sleeping function called from invalid context at %s:%d\n",
8578 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
8579 in_atomic(), irqs_disabled(),
8580 current
->pid
, current
->comm
);
8582 debug_show_held_locks(current
);
8583 if (irqs_disabled())
8584 print_irqtrace_events(current
);
8588 EXPORT_SYMBOL(__might_sleep
);
8591 #ifdef CONFIG_MAGIC_SYSRQ
8592 static void normalize_task(struct rq
*rq
, struct task_struct
*p
)
8596 update_rq_clock(rq
);
8597 on_rq
= p
->se
.on_rq
;
8599 deactivate_task(rq
, p
, 0);
8600 __setscheduler(rq
, p
, SCHED_NORMAL
, 0);
8602 activate_task(rq
, p
, 0);
8603 resched_task(rq
->curr
);
8607 void normalize_rt_tasks(void)
8609 struct task_struct
*g
, *p
;
8610 unsigned long flags
;
8613 read_lock_irqsave(&tasklist_lock
, flags
);
8614 do_each_thread(g
, p
) {
8616 * Only normalize user tasks:
8621 p
->se
.exec_start
= 0;
8622 #ifdef CONFIG_SCHEDSTATS
8623 p
->se
.wait_start
= 0;
8624 p
->se
.sleep_start
= 0;
8625 p
->se
.block_start
= 0;
8630 * Renice negative nice level userspace
8633 if (TASK_NICE(p
) < 0 && p
->mm
)
8634 set_user_nice(p
, 0);
8638 spin_lock(&p
->pi_lock
);
8639 rq
= __task_rq_lock(p
);
8641 normalize_task(rq
, p
);
8643 __task_rq_unlock(rq
);
8644 spin_unlock(&p
->pi_lock
);
8645 } while_each_thread(g
, p
);
8647 read_unlock_irqrestore(&tasklist_lock
, flags
);
8650 #endif /* CONFIG_MAGIC_SYSRQ */
8654 * These functions are only useful for the IA64 MCA handling.
8656 * They can only be called when the whole system has been
8657 * stopped - every CPU needs to be quiescent, and no scheduling
8658 * activity can take place. Using them for anything else would
8659 * be a serious bug, and as a result, they aren't even visible
8660 * under any other configuration.
8664 * curr_task - return the current task for a given cpu.
8665 * @cpu: the processor in question.
8667 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
8669 struct task_struct
*curr_task(int cpu
)
8671 return cpu_curr(cpu
);
8675 * set_curr_task - set the current task for a given cpu.
8676 * @cpu: the processor in question.
8677 * @p: the task pointer to set.
8679 * Description: This function must only be used when non-maskable interrupts
8680 * are serviced on a separate stack. It allows the architecture to switch the
8681 * notion of the current task on a cpu in a non-blocking manner. This function
8682 * must be called with all CPU's synchronized, and interrupts disabled, the
8683 * and caller must save the original value of the current task (see
8684 * curr_task() above) and restore that value before reenabling interrupts and
8685 * re-starting the system.
8687 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
8689 void set_curr_task(int cpu
, struct task_struct
*p
)
8696 #ifdef CONFIG_FAIR_GROUP_SCHED
8697 static void free_fair_sched_group(struct task_group
*tg
)
8701 for_each_possible_cpu(i
) {
8703 kfree(tg
->cfs_rq
[i
]);
8713 int alloc_fair_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8715 struct cfs_rq
*cfs_rq
;
8716 struct sched_entity
*se
;
8720 tg
->cfs_rq
= kzalloc(sizeof(cfs_rq
) * nr_cpu_ids
, GFP_KERNEL
);
8723 tg
->se
= kzalloc(sizeof(se
) * nr_cpu_ids
, GFP_KERNEL
);
8727 tg
->shares
= NICE_0_LOAD
;
8729 for_each_possible_cpu(i
) {
8732 cfs_rq
= kzalloc_node(sizeof(struct cfs_rq
),
8733 GFP_KERNEL
, cpu_to_node(i
));
8737 se
= kzalloc_node(sizeof(struct sched_entity
),
8738 GFP_KERNEL
, cpu_to_node(i
));
8742 init_tg_cfs_entry(tg
, cfs_rq
, se
, i
, 0, parent
->se
[i
]);
8751 static inline void register_fair_sched_group(struct task_group
*tg
, int cpu
)
8753 list_add_rcu(&tg
->cfs_rq
[cpu
]->leaf_cfs_rq_list
,
8754 &cpu_rq(cpu
)->leaf_cfs_rq_list
);
8757 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
8759 list_del_rcu(&tg
->cfs_rq
[cpu
]->leaf_cfs_rq_list
);
8761 #else /* !CONFG_FAIR_GROUP_SCHED */
8762 static inline void free_fair_sched_group(struct task_group
*tg
)
8767 int alloc_fair_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8772 static inline void register_fair_sched_group(struct task_group
*tg
, int cpu
)
8776 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
8779 #endif /* CONFIG_FAIR_GROUP_SCHED */
8781 #ifdef CONFIG_RT_GROUP_SCHED
8782 static void free_rt_sched_group(struct task_group
*tg
)
8786 destroy_rt_bandwidth(&tg
->rt_bandwidth
);
8788 for_each_possible_cpu(i
) {
8790 kfree(tg
->rt_rq
[i
]);
8792 kfree(tg
->rt_se
[i
]);
8800 int alloc_rt_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8802 struct rt_rq
*rt_rq
;
8803 struct sched_rt_entity
*rt_se
;
8807 tg
->rt_rq
= kzalloc(sizeof(rt_rq
) * nr_cpu_ids
, GFP_KERNEL
);
8810 tg
->rt_se
= kzalloc(sizeof(rt_se
) * nr_cpu_ids
, GFP_KERNEL
);
8814 init_rt_bandwidth(&tg
->rt_bandwidth
,
8815 ktime_to_ns(def_rt_bandwidth
.rt_period
), 0);
8817 for_each_possible_cpu(i
) {
8820 rt_rq
= kzalloc_node(sizeof(struct rt_rq
),
8821 GFP_KERNEL
, cpu_to_node(i
));
8825 rt_se
= kzalloc_node(sizeof(struct sched_rt_entity
),
8826 GFP_KERNEL
, cpu_to_node(i
));
8830 init_tg_rt_entry(tg
, rt_rq
, rt_se
, i
, 0, parent
->rt_se
[i
]);
8839 static inline void register_rt_sched_group(struct task_group
*tg
, int cpu
)
8841 list_add_rcu(&tg
->rt_rq
[cpu
]->leaf_rt_rq_list
,
8842 &cpu_rq(cpu
)->leaf_rt_rq_list
);
8845 static inline void unregister_rt_sched_group(struct task_group
*tg
, int cpu
)
8847 list_del_rcu(&tg
->rt_rq
[cpu
]->leaf_rt_rq_list
);
8849 #else /* !CONFIG_RT_GROUP_SCHED */
8850 static inline void free_rt_sched_group(struct task_group
*tg
)
8855 int alloc_rt_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8860 static inline void register_rt_sched_group(struct task_group
*tg
, int cpu
)
8864 static inline void unregister_rt_sched_group(struct task_group
*tg
, int cpu
)
8867 #endif /* CONFIG_RT_GROUP_SCHED */
8869 #ifdef CONFIG_GROUP_SCHED
8870 static void free_sched_group(struct task_group
*tg
)
8872 free_fair_sched_group(tg
);
8873 free_rt_sched_group(tg
);
8877 /* allocate runqueue etc for a new task group */
8878 struct task_group
*sched_create_group(struct task_group
*parent
)
8880 struct task_group
*tg
;
8881 unsigned long flags
;
8884 tg
= kzalloc(sizeof(*tg
), GFP_KERNEL
);
8886 return ERR_PTR(-ENOMEM
);
8888 if (!alloc_fair_sched_group(tg
, parent
))
8891 if (!alloc_rt_sched_group(tg
, parent
))
8894 spin_lock_irqsave(&task_group_lock
, flags
);
8895 for_each_possible_cpu(i
) {
8896 register_fair_sched_group(tg
, i
);
8897 register_rt_sched_group(tg
, i
);
8899 list_add_rcu(&tg
->list
, &task_groups
);
8901 WARN_ON(!parent
); /* root should already exist */
8903 tg
->parent
= parent
;
8904 INIT_LIST_HEAD(&tg
->children
);
8905 list_add_rcu(&tg
->siblings
, &parent
->children
);
8906 spin_unlock_irqrestore(&task_group_lock
, flags
);
8911 free_sched_group(tg
);
8912 return ERR_PTR(-ENOMEM
);
8915 /* rcu callback to free various structures associated with a task group */
8916 static void free_sched_group_rcu(struct rcu_head
*rhp
)
8918 /* now it should be safe to free those cfs_rqs */
8919 free_sched_group(container_of(rhp
, struct task_group
, rcu
));
8922 /* Destroy runqueue etc associated with a task group */
8923 void sched_destroy_group(struct task_group
*tg
)
8925 unsigned long flags
;
8928 spin_lock_irqsave(&task_group_lock
, flags
);
8929 for_each_possible_cpu(i
) {
8930 unregister_fair_sched_group(tg
, i
);
8931 unregister_rt_sched_group(tg
, i
);
8933 list_del_rcu(&tg
->list
);
8934 list_del_rcu(&tg
->siblings
);
8935 spin_unlock_irqrestore(&task_group_lock
, flags
);
8937 /* wait for possible concurrent references to cfs_rqs complete */
8938 call_rcu(&tg
->rcu
, free_sched_group_rcu
);
8941 /* change task's runqueue when it moves between groups.
8942 * The caller of this function should have put the task in its new group
8943 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
8944 * reflect its new group.
8946 void sched_move_task(struct task_struct
*tsk
)
8949 unsigned long flags
;
8952 rq
= task_rq_lock(tsk
, &flags
);
8954 update_rq_clock(rq
);
8956 running
= task_current(rq
, tsk
);
8957 on_rq
= tsk
->se
.on_rq
;
8960 dequeue_task(rq
, tsk
, 0);
8961 if (unlikely(running
))
8962 tsk
->sched_class
->put_prev_task(rq
, tsk
);
8964 set_task_rq(tsk
, task_cpu(tsk
));
8966 #ifdef CONFIG_FAIR_GROUP_SCHED
8967 if (tsk
->sched_class
->moved_group
)
8968 tsk
->sched_class
->moved_group(tsk
);
8971 if (unlikely(running
))
8972 tsk
->sched_class
->set_curr_task(rq
);
8974 enqueue_task(rq
, tsk
, 0);
8976 task_rq_unlock(rq
, &flags
);
8978 #endif /* CONFIG_GROUP_SCHED */
8980 #ifdef CONFIG_FAIR_GROUP_SCHED
8981 static void __set_se_shares(struct sched_entity
*se
, unsigned long shares
)
8983 struct cfs_rq
*cfs_rq
= se
->cfs_rq
;
8988 dequeue_entity(cfs_rq
, se
, 0);
8990 se
->load
.weight
= shares
;
8991 se
->load
.inv_weight
= 0;
8994 enqueue_entity(cfs_rq
, se
, 0);
8997 static void set_se_shares(struct sched_entity
*se
, unsigned long shares
)
8999 struct cfs_rq
*cfs_rq
= se
->cfs_rq
;
9000 struct rq
*rq
= cfs_rq
->rq
;
9001 unsigned long flags
;
9003 spin_lock_irqsave(&rq
->lock
, flags
);
9004 __set_se_shares(se
, shares
);
9005 spin_unlock_irqrestore(&rq
->lock
, flags
);
9008 static DEFINE_MUTEX(shares_mutex
);
9010 int sched_group_set_shares(struct task_group
*tg
, unsigned long shares
)
9013 unsigned long flags
;
9016 * We can't change the weight of the root cgroup.
9021 if (shares
< MIN_SHARES
)
9022 shares
= MIN_SHARES
;
9023 else if (shares
> MAX_SHARES
)
9024 shares
= MAX_SHARES
;
9026 mutex_lock(&shares_mutex
);
9027 if (tg
->shares
== shares
)
9030 spin_lock_irqsave(&task_group_lock
, flags
);
9031 for_each_possible_cpu(i
)
9032 unregister_fair_sched_group(tg
, i
);
9033 list_del_rcu(&tg
->siblings
);
9034 spin_unlock_irqrestore(&task_group_lock
, flags
);
9036 /* wait for any ongoing reference to this group to finish */
9037 synchronize_sched();
9040 * Now we are free to modify the group's share on each cpu
9041 * w/o tripping rebalance_share or load_balance_fair.
9043 tg
->shares
= shares
;
9044 for_each_possible_cpu(i
) {
9048 cfs_rq_set_shares(tg
->cfs_rq
[i
], 0);
9049 set_se_shares(tg
->se
[i
], shares
);
9053 * Enable load balance activity on this group, by inserting it back on
9054 * each cpu's rq->leaf_cfs_rq_list.
9056 spin_lock_irqsave(&task_group_lock
, flags
);
9057 for_each_possible_cpu(i
)
9058 register_fair_sched_group(tg
, i
);
9059 list_add_rcu(&tg
->siblings
, &tg
->parent
->children
);
9060 spin_unlock_irqrestore(&task_group_lock
, flags
);
9062 mutex_unlock(&shares_mutex
);
9066 unsigned long sched_group_shares(struct task_group
*tg
)
9072 #ifdef CONFIG_RT_GROUP_SCHED
9074 * Ensure that the real time constraints are schedulable.
9076 static DEFINE_MUTEX(rt_constraints_mutex
);
9078 static unsigned long to_ratio(u64 period
, u64 runtime
)
9080 if (runtime
== RUNTIME_INF
)
9083 return div64_u64(runtime
<< 20, period
);
9086 /* Must be called with tasklist_lock held */
9087 static inline int tg_has_rt_tasks(struct task_group
*tg
)
9089 struct task_struct
*g
, *p
;
9091 do_each_thread(g
, p
) {
9092 if (rt_task(p
) && rt_rq_of_se(&p
->rt
)->tg
== tg
)
9094 } while_each_thread(g
, p
);
9099 struct rt_schedulable_data
{
9100 struct task_group
*tg
;
9105 static int tg_schedulable(struct task_group
*tg
, void *data
)
9107 struct rt_schedulable_data
*d
= data
;
9108 struct task_group
*child
;
9109 unsigned long total
, sum
= 0;
9110 u64 period
, runtime
;
9112 period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
9113 runtime
= tg
->rt_bandwidth
.rt_runtime
;
9116 period
= d
->rt_period
;
9117 runtime
= d
->rt_runtime
;
9121 * Cannot have more runtime than the period.
9123 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
9127 * Ensure we don't starve existing RT tasks.
9129 if (rt_bandwidth_enabled() && !runtime
&& tg_has_rt_tasks(tg
))
9132 total
= to_ratio(period
, runtime
);
9135 * Nobody can have more than the global setting allows.
9137 if (total
> to_ratio(global_rt_period(), global_rt_runtime()))
9141 * The sum of our children's runtime should not exceed our own.
9143 list_for_each_entry_rcu(child
, &tg
->children
, siblings
) {
9144 period
= ktime_to_ns(child
->rt_bandwidth
.rt_period
);
9145 runtime
= child
->rt_bandwidth
.rt_runtime
;
9147 if (child
== d
->tg
) {
9148 period
= d
->rt_period
;
9149 runtime
= d
->rt_runtime
;
9152 sum
+= to_ratio(period
, runtime
);
9161 static int __rt_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
)
9163 struct rt_schedulable_data data
= {
9165 .rt_period
= period
,
9166 .rt_runtime
= runtime
,
9169 return walk_tg_tree(tg_schedulable
, tg_nop
, &data
);
9172 static int tg_set_bandwidth(struct task_group
*tg
,
9173 u64 rt_period
, u64 rt_runtime
)
9177 mutex_lock(&rt_constraints_mutex
);
9178 read_lock(&tasklist_lock
);
9179 err
= __rt_schedulable(tg
, rt_period
, rt_runtime
);
9183 spin_lock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
9184 tg
->rt_bandwidth
.rt_period
= ns_to_ktime(rt_period
);
9185 tg
->rt_bandwidth
.rt_runtime
= rt_runtime
;
9187 for_each_possible_cpu(i
) {
9188 struct rt_rq
*rt_rq
= tg
->rt_rq
[i
];
9190 spin_lock(&rt_rq
->rt_runtime_lock
);
9191 rt_rq
->rt_runtime
= rt_runtime
;
9192 spin_unlock(&rt_rq
->rt_runtime_lock
);
9194 spin_unlock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
9196 read_unlock(&tasklist_lock
);
9197 mutex_unlock(&rt_constraints_mutex
);
9202 int sched_group_set_rt_runtime(struct task_group
*tg
, long rt_runtime_us
)
9204 u64 rt_runtime
, rt_period
;
9206 rt_period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
9207 rt_runtime
= (u64
)rt_runtime_us
* NSEC_PER_USEC
;
9208 if (rt_runtime_us
< 0)
9209 rt_runtime
= RUNTIME_INF
;
9211 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
9214 long sched_group_rt_runtime(struct task_group
*tg
)
9218 if (tg
->rt_bandwidth
.rt_runtime
== RUNTIME_INF
)
9221 rt_runtime_us
= tg
->rt_bandwidth
.rt_runtime
;
9222 do_div(rt_runtime_us
, NSEC_PER_USEC
);
9223 return rt_runtime_us
;
9226 int sched_group_set_rt_period(struct task_group
*tg
, long rt_period_us
)
9228 u64 rt_runtime
, rt_period
;
9230 rt_period
= (u64
)rt_period_us
* NSEC_PER_USEC
;
9231 rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
9236 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
9239 long sched_group_rt_period(struct task_group
*tg
)
9243 rt_period_us
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
9244 do_div(rt_period_us
, NSEC_PER_USEC
);
9245 return rt_period_us
;
9248 static int sched_rt_global_constraints(void)
9250 u64 runtime
, period
;
9253 if (sysctl_sched_rt_period
<= 0)
9256 runtime
= global_rt_runtime();
9257 period
= global_rt_period();
9260 * Sanity check on the sysctl variables.
9262 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
9265 mutex_lock(&rt_constraints_mutex
);
9266 read_lock(&tasklist_lock
);
9267 ret
= __rt_schedulable(NULL
, 0, 0);
9268 read_unlock(&tasklist_lock
);
9269 mutex_unlock(&rt_constraints_mutex
);
9273 #else /* !CONFIG_RT_GROUP_SCHED */
9274 static int sched_rt_global_constraints(void)
9276 unsigned long flags
;
9279 if (sysctl_sched_rt_period
<= 0)
9282 spin_lock_irqsave(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
9283 for_each_possible_cpu(i
) {
9284 struct rt_rq
*rt_rq
= &cpu_rq(i
)->rt
;
9286 spin_lock(&rt_rq
->rt_runtime_lock
);
9287 rt_rq
->rt_runtime
= global_rt_runtime();
9288 spin_unlock(&rt_rq
->rt_runtime_lock
);
9290 spin_unlock_irqrestore(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
9294 #endif /* CONFIG_RT_GROUP_SCHED */
9296 int sched_rt_handler(struct ctl_table
*table
, int write
,
9297 struct file
*filp
, void __user
*buffer
, size_t *lenp
,
9301 int old_period
, old_runtime
;
9302 static DEFINE_MUTEX(mutex
);
9305 old_period
= sysctl_sched_rt_period
;
9306 old_runtime
= sysctl_sched_rt_runtime
;
9308 ret
= proc_dointvec(table
, write
, filp
, buffer
, lenp
, ppos
);
9310 if (!ret
&& write
) {
9311 ret
= sched_rt_global_constraints();
9313 sysctl_sched_rt_period
= old_period
;
9314 sysctl_sched_rt_runtime
= old_runtime
;
9316 def_rt_bandwidth
.rt_runtime
= global_rt_runtime();
9317 def_rt_bandwidth
.rt_period
=
9318 ns_to_ktime(global_rt_period());
9321 mutex_unlock(&mutex
);
9326 #ifdef CONFIG_CGROUP_SCHED
9328 /* return corresponding task_group object of a cgroup */
9329 static inline struct task_group
*cgroup_tg(struct cgroup
*cgrp
)
9331 return container_of(cgroup_subsys_state(cgrp
, cpu_cgroup_subsys_id
),
9332 struct task_group
, css
);
9335 static struct cgroup_subsys_state
*
9336 cpu_cgroup_create(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
9338 struct task_group
*tg
, *parent
;
9340 if (!cgrp
->parent
) {
9341 /* This is early initialization for the top cgroup */
9342 return &init_task_group
.css
;
9345 parent
= cgroup_tg(cgrp
->parent
);
9346 tg
= sched_create_group(parent
);
9348 return ERR_PTR(-ENOMEM
);
9354 cpu_cgroup_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
9356 struct task_group
*tg
= cgroup_tg(cgrp
);
9358 sched_destroy_group(tg
);
9362 cpu_cgroup_can_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
9363 struct task_struct
*tsk
)
9365 #ifdef CONFIG_RT_GROUP_SCHED
9366 /* Don't accept realtime tasks when there is no way for them to run */
9367 if (rt_task(tsk
) && cgroup_tg(cgrp
)->rt_bandwidth
.rt_runtime
== 0)
9370 /* We don't support RT-tasks being in separate groups */
9371 if (tsk
->sched_class
!= &fair_sched_class
)
9379 cpu_cgroup_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
9380 struct cgroup
*old_cont
, struct task_struct
*tsk
)
9382 sched_move_task(tsk
);
9385 #ifdef CONFIG_FAIR_GROUP_SCHED
9386 static int cpu_shares_write_u64(struct cgroup
*cgrp
, struct cftype
*cftype
,
9389 return sched_group_set_shares(cgroup_tg(cgrp
), shareval
);
9392 static u64
cpu_shares_read_u64(struct cgroup
*cgrp
, struct cftype
*cft
)
9394 struct task_group
*tg
= cgroup_tg(cgrp
);
9396 return (u64
) tg
->shares
;
9398 #endif /* CONFIG_FAIR_GROUP_SCHED */
9400 #ifdef CONFIG_RT_GROUP_SCHED
9401 static int cpu_rt_runtime_write(struct cgroup
*cgrp
, struct cftype
*cft
,
9404 return sched_group_set_rt_runtime(cgroup_tg(cgrp
), val
);
9407 static s64
cpu_rt_runtime_read(struct cgroup
*cgrp
, struct cftype
*cft
)
9409 return sched_group_rt_runtime(cgroup_tg(cgrp
));
9412 static int cpu_rt_period_write_uint(struct cgroup
*cgrp
, struct cftype
*cftype
,
9415 return sched_group_set_rt_period(cgroup_tg(cgrp
), rt_period_us
);
9418 static u64
cpu_rt_period_read_uint(struct cgroup
*cgrp
, struct cftype
*cft
)
9420 return sched_group_rt_period(cgroup_tg(cgrp
));
9422 #endif /* CONFIG_RT_GROUP_SCHED */
9424 static struct cftype cpu_files
[] = {
9425 #ifdef CONFIG_FAIR_GROUP_SCHED
9428 .read_u64
= cpu_shares_read_u64
,
9429 .write_u64
= cpu_shares_write_u64
,
9432 #ifdef CONFIG_RT_GROUP_SCHED
9434 .name
= "rt_runtime_us",
9435 .read_s64
= cpu_rt_runtime_read
,
9436 .write_s64
= cpu_rt_runtime_write
,
9439 .name
= "rt_period_us",
9440 .read_u64
= cpu_rt_period_read_uint
,
9441 .write_u64
= cpu_rt_period_write_uint
,
9446 static int cpu_cgroup_populate(struct cgroup_subsys
*ss
, struct cgroup
*cont
)
9448 return cgroup_add_files(cont
, ss
, cpu_files
, ARRAY_SIZE(cpu_files
));
9451 struct cgroup_subsys cpu_cgroup_subsys
= {
9453 .create
= cpu_cgroup_create
,
9454 .destroy
= cpu_cgroup_destroy
,
9455 .can_attach
= cpu_cgroup_can_attach
,
9456 .attach
= cpu_cgroup_attach
,
9457 .populate
= cpu_cgroup_populate
,
9458 .subsys_id
= cpu_cgroup_subsys_id
,
9462 #endif /* CONFIG_CGROUP_SCHED */
9464 #ifdef CONFIG_CGROUP_CPUACCT
9467 * CPU accounting code for task groups.
9469 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
9470 * (balbir@in.ibm.com).
9473 /* track cpu usage of a group of tasks and its child groups */
9475 struct cgroup_subsys_state css
;
9476 /* cpuusage holds pointer to a u64-type object on every cpu */
9478 struct cpuacct
*parent
;
9481 struct cgroup_subsys cpuacct_subsys
;
9483 /* return cpu accounting group corresponding to this container */
9484 static inline struct cpuacct
*cgroup_ca(struct cgroup
*cgrp
)
9486 return container_of(cgroup_subsys_state(cgrp
, cpuacct_subsys_id
),
9487 struct cpuacct
, css
);
9490 /* return cpu accounting group to which this task belongs */
9491 static inline struct cpuacct
*task_ca(struct task_struct
*tsk
)
9493 return container_of(task_subsys_state(tsk
, cpuacct_subsys_id
),
9494 struct cpuacct
, css
);
9497 /* create a new cpu accounting group */
9498 static struct cgroup_subsys_state
*cpuacct_create(
9499 struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
9501 struct cpuacct
*ca
= kzalloc(sizeof(*ca
), GFP_KERNEL
);
9504 return ERR_PTR(-ENOMEM
);
9506 ca
->cpuusage
= alloc_percpu(u64
);
9507 if (!ca
->cpuusage
) {
9509 return ERR_PTR(-ENOMEM
);
9513 ca
->parent
= cgroup_ca(cgrp
->parent
);
9518 /* destroy an existing cpu accounting group */
9520 cpuacct_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
9522 struct cpuacct
*ca
= cgroup_ca(cgrp
);
9524 free_percpu(ca
->cpuusage
);
9528 static u64
cpuacct_cpuusage_read(struct cpuacct
*ca
, int cpu
)
9530 u64
*cpuusage
= percpu_ptr(ca
->cpuusage
, cpu
);
9533 #ifndef CONFIG_64BIT
9535 * Take rq->lock to make 64-bit read safe on 32-bit platforms.
9537 spin_lock_irq(&cpu_rq(cpu
)->lock
);
9539 spin_unlock_irq(&cpu_rq(cpu
)->lock
);
9547 static void cpuacct_cpuusage_write(struct cpuacct
*ca
, int cpu
, u64 val
)
9549 u64
*cpuusage
= percpu_ptr(ca
->cpuusage
, cpu
);
9551 #ifndef CONFIG_64BIT
9553 * Take rq->lock to make 64-bit write safe on 32-bit platforms.
9555 spin_lock_irq(&cpu_rq(cpu
)->lock
);
9557 spin_unlock_irq(&cpu_rq(cpu
)->lock
);
9563 /* return total cpu usage (in nanoseconds) of a group */
9564 static u64
cpuusage_read(struct cgroup
*cgrp
, struct cftype
*cft
)
9566 struct cpuacct
*ca
= cgroup_ca(cgrp
);
9567 u64 totalcpuusage
= 0;
9570 for_each_present_cpu(i
)
9571 totalcpuusage
+= cpuacct_cpuusage_read(ca
, i
);
9573 return totalcpuusage
;
9576 static int cpuusage_write(struct cgroup
*cgrp
, struct cftype
*cftype
,
9579 struct cpuacct
*ca
= cgroup_ca(cgrp
);
9588 for_each_present_cpu(i
)
9589 cpuacct_cpuusage_write(ca
, i
, 0);
9595 static int cpuacct_percpu_seq_read(struct cgroup
*cgroup
, struct cftype
*cft
,
9598 struct cpuacct
*ca
= cgroup_ca(cgroup
);
9602 for_each_present_cpu(i
) {
9603 percpu
= cpuacct_cpuusage_read(ca
, i
);
9604 seq_printf(m
, "%llu ", (unsigned long long) percpu
);
9606 seq_printf(m
, "\n");
9610 static struct cftype files
[] = {
9613 .read_u64
= cpuusage_read
,
9614 .write_u64
= cpuusage_write
,
9617 .name
= "usage_percpu",
9618 .read_seq_string
= cpuacct_percpu_seq_read
,
9623 static int cpuacct_populate(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
9625 return cgroup_add_files(cgrp
, ss
, files
, ARRAY_SIZE(files
));
9629 * charge this task's execution time to its accounting group.
9631 * called with rq->lock held.
9633 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
)
9638 if (!cpuacct_subsys
.active
)
9641 cpu
= task_cpu(tsk
);
9644 for (; ca
; ca
= ca
->parent
) {
9645 u64
*cpuusage
= percpu_ptr(ca
->cpuusage
, cpu
);
9646 *cpuusage
+= cputime
;
9650 struct cgroup_subsys cpuacct_subsys
= {
9652 .create
= cpuacct_create
,
9653 .destroy
= cpuacct_destroy
,
9654 .populate
= cpuacct_populate
,
9655 .subsys_id
= cpuacct_subsys_id
,
9657 #endif /* CONFIG_CGROUP_CPUACCT */