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/perf_event.h>
43 #include <linux/security.h>
44 #include <linux/notifier.h>
45 #include <linux/profile.h>
46 #include <linux/freezer.h>
47 #include <linux/vmalloc.h>
48 #include <linux/blkdev.h>
49 #include <linux/delay.h>
50 #include <linux/pid_namespace.h>
51 #include <linux/smp.h>
52 #include <linux/threads.h>
53 #include <linux/timer.h>
54 #include <linux/rcupdate.h>
55 #include <linux/cpu.h>
56 #include <linux/cpuset.h>
57 #include <linux/percpu.h>
58 #include <linux/kthread.h>
59 #include <linux/proc_fs.h>
60 #include <linux/seq_file.h>
61 #include <linux/sysctl.h>
62 #include <linux/syscalls.h>
63 #include <linux/times.h>
64 #include <linux/tsacct_kern.h>
65 #include <linux/kprobes.h>
66 #include <linux/delayacct.h>
67 #include <linux/unistd.h>
68 #include <linux/pagemap.h>
69 #include <linux/hrtimer.h>
70 #include <linux/tick.h>
71 #include <linux/debugfs.h>
72 #include <linux/ctype.h>
73 #include <linux/ftrace.h>
76 #include <asm/irq_regs.h>
78 #include "sched_cpupri.h"
80 #define CREATE_TRACE_POINTS
81 #include <trace/events/sched.h>
84 * Convert user-nice values [ -20 ... 0 ... 19 ]
85 * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
88 #define NICE_TO_PRIO(nice) (MAX_RT_PRIO + (nice) + 20)
89 #define PRIO_TO_NICE(prio) ((prio) - MAX_RT_PRIO - 20)
90 #define TASK_NICE(p) PRIO_TO_NICE((p)->static_prio)
93 * 'User priority' is the nice value converted to something we
94 * can work with better when scaling various scheduler parameters,
95 * it's a [ 0 ... 39 ] range.
97 #define USER_PRIO(p) ((p)-MAX_RT_PRIO)
98 #define TASK_USER_PRIO(p) USER_PRIO((p)->static_prio)
99 #define MAX_USER_PRIO (USER_PRIO(MAX_PRIO))
102 * Helpers for converting nanosecond timing to jiffy resolution
104 #define NS_TO_JIFFIES(TIME) ((unsigned long)(TIME) / (NSEC_PER_SEC / HZ))
106 #define NICE_0_LOAD SCHED_LOAD_SCALE
107 #define NICE_0_SHIFT SCHED_LOAD_SHIFT
110 * These are the 'tuning knobs' of the scheduler:
112 * default timeslice is 100 msecs (used only for SCHED_RR tasks).
113 * Timeslices get refilled after they expire.
115 #define DEF_TIMESLICE (100 * HZ / 1000)
118 * single value that denotes runtime == period, ie unlimited time.
120 #define RUNTIME_INF ((u64)~0ULL)
122 static inline int rt_policy(int policy
)
124 if (unlikely(policy
== SCHED_FIFO
|| policy
== SCHED_RR
))
129 static inline int task_has_rt_policy(struct task_struct
*p
)
131 return rt_policy(p
->policy
);
135 * This is the priority-queue data structure of the RT scheduling class:
137 struct rt_prio_array
{
138 DECLARE_BITMAP(bitmap
, MAX_RT_PRIO
+1); /* include 1 bit for delimiter */
139 struct list_head queue
[MAX_RT_PRIO
];
142 struct rt_bandwidth
{
143 /* nests inside the rq lock: */
144 spinlock_t rt_runtime_lock
;
147 struct hrtimer rt_period_timer
;
150 static struct rt_bandwidth def_rt_bandwidth
;
152 static int do_sched_rt_period_timer(struct rt_bandwidth
*rt_b
, int overrun
);
154 static enum hrtimer_restart
sched_rt_period_timer(struct hrtimer
*timer
)
156 struct rt_bandwidth
*rt_b
=
157 container_of(timer
, struct rt_bandwidth
, rt_period_timer
);
163 now
= hrtimer_cb_get_time(timer
);
164 overrun
= hrtimer_forward(timer
, now
, rt_b
->rt_period
);
169 idle
= do_sched_rt_period_timer(rt_b
, overrun
);
172 return idle
? HRTIMER_NORESTART
: HRTIMER_RESTART
;
176 void init_rt_bandwidth(struct rt_bandwidth
*rt_b
, u64 period
, u64 runtime
)
178 rt_b
->rt_period
= ns_to_ktime(period
);
179 rt_b
->rt_runtime
= runtime
;
181 spin_lock_init(&rt_b
->rt_runtime_lock
);
183 hrtimer_init(&rt_b
->rt_period_timer
,
184 CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
185 rt_b
->rt_period_timer
.function
= sched_rt_period_timer
;
188 static inline int rt_bandwidth_enabled(void)
190 return sysctl_sched_rt_runtime
>= 0;
193 static void start_rt_bandwidth(struct rt_bandwidth
*rt_b
)
197 if (!rt_bandwidth_enabled() || rt_b
->rt_runtime
== RUNTIME_INF
)
200 if (hrtimer_active(&rt_b
->rt_period_timer
))
203 spin_lock(&rt_b
->rt_runtime_lock
);
208 if (hrtimer_active(&rt_b
->rt_period_timer
))
211 now
= hrtimer_cb_get_time(&rt_b
->rt_period_timer
);
212 hrtimer_forward(&rt_b
->rt_period_timer
, now
, rt_b
->rt_period
);
214 soft
= hrtimer_get_softexpires(&rt_b
->rt_period_timer
);
215 hard
= hrtimer_get_expires(&rt_b
->rt_period_timer
);
216 delta
= ktime_to_ns(ktime_sub(hard
, soft
));
217 __hrtimer_start_range_ns(&rt_b
->rt_period_timer
, soft
, delta
,
218 HRTIMER_MODE_ABS_PINNED
, 0);
220 spin_unlock(&rt_b
->rt_runtime_lock
);
223 #ifdef CONFIG_RT_GROUP_SCHED
224 static void destroy_rt_bandwidth(struct rt_bandwidth
*rt_b
)
226 hrtimer_cancel(&rt_b
->rt_period_timer
);
231 * sched_domains_mutex serializes calls to arch_init_sched_domains,
232 * detach_destroy_domains and partition_sched_domains.
234 static DEFINE_MUTEX(sched_domains_mutex
);
236 #ifdef CONFIG_GROUP_SCHED
238 #include <linux/cgroup.h>
242 static LIST_HEAD(task_groups
);
244 /* task group related information */
246 #ifdef CONFIG_CGROUP_SCHED
247 struct cgroup_subsys_state css
;
250 #ifdef CONFIG_USER_SCHED
254 #ifdef CONFIG_FAIR_GROUP_SCHED
255 /* schedulable entities of this group on each cpu */
256 struct sched_entity
**se
;
257 /* runqueue "owned" by this group on each cpu */
258 struct cfs_rq
**cfs_rq
;
259 unsigned long shares
;
262 #ifdef CONFIG_RT_GROUP_SCHED
263 struct sched_rt_entity
**rt_se
;
264 struct rt_rq
**rt_rq
;
266 struct rt_bandwidth rt_bandwidth
;
270 struct list_head list
;
272 struct task_group
*parent
;
273 struct list_head siblings
;
274 struct list_head children
;
277 #ifdef CONFIG_USER_SCHED
279 /* Helper function to pass uid information to create_sched_user() */
280 void set_tg_uid(struct user_struct
*user
)
282 user
->tg
->uid
= user
->uid
;
287 * Every UID task group (including init_task_group aka UID-0) will
288 * be a child to this group.
290 struct task_group root_task_group
;
292 #ifdef CONFIG_FAIR_GROUP_SCHED
293 /* Default task group's sched entity on each cpu */
294 static DEFINE_PER_CPU(struct sched_entity
, init_sched_entity
);
295 /* Default task group's cfs_rq on each cpu */
296 static DEFINE_PER_CPU_SHARED_ALIGNED(struct cfs_rq
, init_tg_cfs_rq
);
297 #endif /* CONFIG_FAIR_GROUP_SCHED */
299 #ifdef CONFIG_RT_GROUP_SCHED
300 static DEFINE_PER_CPU(struct sched_rt_entity
, init_sched_rt_entity
);
301 static DEFINE_PER_CPU_SHARED_ALIGNED(struct rt_rq
, init_rt_rq
);
302 #endif /* CONFIG_RT_GROUP_SCHED */
303 #else /* !CONFIG_USER_SCHED */
304 #define root_task_group init_task_group
305 #endif /* CONFIG_USER_SCHED */
307 /* task_group_lock serializes add/remove of task groups and also changes to
308 * a task group's cpu shares.
310 static DEFINE_SPINLOCK(task_group_lock
);
312 #ifdef CONFIG_FAIR_GROUP_SCHED
315 static int root_task_group_empty(void)
317 return list_empty(&root_task_group
.children
);
321 #ifdef CONFIG_USER_SCHED
322 # define INIT_TASK_GROUP_LOAD (2*NICE_0_LOAD)
323 #else /* !CONFIG_USER_SCHED */
324 # define INIT_TASK_GROUP_LOAD NICE_0_LOAD
325 #endif /* CONFIG_USER_SCHED */
328 * A weight of 0 or 1 can cause arithmetics problems.
329 * A weight of a cfs_rq is the sum of weights of which entities
330 * are queued on this cfs_rq, so a weight of a entity should not be
331 * too large, so as the shares value of a task group.
332 * (The default weight is 1024 - so there's no practical
333 * limitation from this.)
336 #define MAX_SHARES (1UL << 18)
338 static int init_task_group_load
= INIT_TASK_GROUP_LOAD
;
341 /* Default task group.
342 * Every task in system belong to this group at bootup.
344 struct task_group init_task_group
;
346 /* return group to which a task belongs */
347 static inline struct task_group
*task_group(struct task_struct
*p
)
349 struct task_group
*tg
;
351 #ifdef CONFIG_USER_SCHED
353 tg
= __task_cred(p
)->user
->tg
;
355 #elif defined(CONFIG_CGROUP_SCHED)
356 tg
= container_of(task_subsys_state(p
, cpu_cgroup_subsys_id
),
357 struct task_group
, css
);
359 tg
= &init_task_group
;
364 /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
365 static inline void set_task_rq(struct task_struct
*p
, unsigned int cpu
)
367 #ifdef CONFIG_FAIR_GROUP_SCHED
368 p
->se
.cfs_rq
= task_group(p
)->cfs_rq
[cpu
];
369 p
->se
.parent
= task_group(p
)->se
[cpu
];
372 #ifdef CONFIG_RT_GROUP_SCHED
373 p
->rt
.rt_rq
= task_group(p
)->rt_rq
[cpu
];
374 p
->rt
.parent
= task_group(p
)->rt_se
[cpu
];
380 static inline void set_task_rq(struct task_struct
*p
, unsigned int cpu
) { }
381 static inline struct task_group
*task_group(struct task_struct
*p
)
386 #endif /* CONFIG_GROUP_SCHED */
388 /* CFS-related fields in a runqueue */
390 struct load_weight load
;
391 unsigned long nr_running
;
396 struct rb_root tasks_timeline
;
397 struct rb_node
*rb_leftmost
;
399 struct list_head tasks
;
400 struct list_head
*balance_iterator
;
403 * 'curr' points to currently running entity on this cfs_rq.
404 * It is set to NULL otherwise (i.e when none are currently running).
406 struct sched_entity
*curr
, *next
, *last
;
408 unsigned int nr_spread_over
;
410 #ifdef CONFIG_FAIR_GROUP_SCHED
411 struct rq
*rq
; /* cpu runqueue to which this cfs_rq is attached */
414 * leaf cfs_rqs are those that hold tasks (lowest schedulable entity in
415 * a hierarchy). Non-leaf lrqs hold other higher schedulable entities
416 * (like users, containers etc.)
418 * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This
419 * list is used during load balance.
421 struct list_head leaf_cfs_rq_list
;
422 struct task_group
*tg
; /* group that "owns" this runqueue */
426 * the part of load.weight contributed by tasks
428 unsigned long task_weight
;
431 * h_load = weight * f(tg)
433 * Where f(tg) is the recursive weight fraction assigned to
436 unsigned long h_load
;
439 * this cpu's part of tg->shares
441 unsigned long shares
;
444 * load.weight at the time we set shares
446 unsigned long rq_weight
;
451 /* Real-Time classes' related field in a runqueue: */
453 struct rt_prio_array active
;
454 unsigned long rt_nr_running
;
455 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
457 int curr
; /* highest queued rt task prio */
459 int next
; /* next highest */
464 unsigned long rt_nr_migratory
;
465 unsigned long rt_nr_total
;
467 struct plist_head pushable_tasks
;
472 /* Nests inside the rq lock: */
473 spinlock_t rt_runtime_lock
;
475 #ifdef CONFIG_RT_GROUP_SCHED
476 unsigned long rt_nr_boosted
;
479 struct list_head leaf_rt_rq_list
;
480 struct task_group
*tg
;
481 struct sched_rt_entity
*rt_se
;
488 * We add the notion of a root-domain which will be used to define per-domain
489 * variables. Each exclusive cpuset essentially defines an island domain by
490 * fully partitioning the member cpus from any other cpuset. Whenever a new
491 * exclusive cpuset is created, we also create and attach a new root-domain
498 cpumask_var_t online
;
501 * The "RT overload" flag: it gets set if a CPU has more than
502 * one runnable RT task.
504 cpumask_var_t rto_mask
;
507 struct cpupri cpupri
;
512 * By default the system creates a single root-domain with all cpus as
513 * members (mimicking the global state we have today).
515 static struct root_domain def_root_domain
;
520 * This is the main, per-CPU runqueue data structure.
522 * Locking rule: those places that want to lock multiple runqueues
523 * (such as the load balancing or the thread migration code), lock
524 * acquire operations must be ordered by ascending &runqueue.
531 * nr_running and cpu_load should be in the same cacheline because
532 * remote CPUs use both these fields when doing load calculation.
534 unsigned long nr_running
;
535 #define CPU_LOAD_IDX_MAX 5
536 unsigned long cpu_load
[CPU_LOAD_IDX_MAX
];
538 unsigned char in_nohz_recently
;
540 /* capture load from *all* tasks on this cpu: */
541 struct load_weight load
;
542 unsigned long nr_load_updates
;
548 #ifdef CONFIG_FAIR_GROUP_SCHED
549 /* list of leaf cfs_rq on this cpu: */
550 struct list_head leaf_cfs_rq_list
;
552 #ifdef CONFIG_RT_GROUP_SCHED
553 struct list_head leaf_rt_rq_list
;
557 * This is part of a global counter where only the total sum
558 * over all CPUs matters. A task can increase this counter on
559 * one CPU and if it got migrated afterwards it may decrease
560 * it on another CPU. Always updated under the runqueue lock:
562 unsigned long nr_uninterruptible
;
564 struct task_struct
*curr
, *idle
;
565 unsigned long next_balance
;
566 struct mm_struct
*prev_mm
;
573 struct root_domain
*rd
;
574 struct sched_domain
*sd
;
576 unsigned char idle_at_tick
;
577 /* For active balancing */
581 /* cpu of this runqueue: */
585 unsigned long avg_load_per_task
;
587 struct task_struct
*migration_thread
;
588 struct list_head migration_queue
;
596 /* calc_load related fields */
597 unsigned long calc_load_update
;
598 long calc_load_active
;
600 #ifdef CONFIG_SCHED_HRTICK
602 int hrtick_csd_pending
;
603 struct call_single_data hrtick_csd
;
605 struct hrtimer hrtick_timer
;
608 #ifdef CONFIG_SCHEDSTATS
610 struct sched_info rq_sched_info
;
611 unsigned long long rq_cpu_time
;
612 /* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */
614 /* sys_sched_yield() stats */
615 unsigned int yld_count
;
617 /* schedule() stats */
618 unsigned int sched_switch
;
619 unsigned int sched_count
;
620 unsigned int sched_goidle
;
622 /* try_to_wake_up() stats */
623 unsigned int ttwu_count
;
624 unsigned int ttwu_local
;
627 unsigned int bkl_count
;
631 static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq
, runqueues
);
634 void check_preempt_curr(struct rq
*rq
, struct task_struct
*p
, int flags
)
636 rq
->curr
->sched_class
->check_preempt_curr(rq
, p
, flags
);
639 static inline int cpu_of(struct rq
*rq
)
649 * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
650 * See detach_destroy_domains: synchronize_sched for details.
652 * The domain tree of any CPU may only be accessed from within
653 * preempt-disabled sections.
655 #define for_each_domain(cpu, __sd) \
656 for (__sd = rcu_dereference(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent)
658 #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu)))
659 #define this_rq() (&__get_cpu_var(runqueues))
660 #define task_rq(p) cpu_rq(task_cpu(p))
661 #define cpu_curr(cpu) (cpu_rq(cpu)->curr)
662 #define raw_rq() (&__raw_get_cpu_var(runqueues))
664 inline void update_rq_clock(struct rq
*rq
)
666 rq
->clock
= sched_clock_cpu(cpu_of(rq
));
670 * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
672 #ifdef CONFIG_SCHED_DEBUG
673 # define const_debug __read_mostly
675 # define const_debug static const
680 * @cpu: the processor in question.
682 * Returns true if the current cpu runqueue is locked.
683 * This interface allows printk to be called with the runqueue lock
684 * held and know whether or not it is OK to wake up the klogd.
686 int runqueue_is_locked(int cpu
)
688 return spin_is_locked(&cpu_rq(cpu
)->lock
);
692 * Debugging: various feature bits
695 #define SCHED_FEAT(name, enabled) \
696 __SCHED_FEAT_##name ,
699 #include "sched_features.h"
704 #define SCHED_FEAT(name, enabled) \
705 (1UL << __SCHED_FEAT_##name) * enabled |
707 const_debug
unsigned int sysctl_sched_features
=
708 #include "sched_features.h"
713 #ifdef CONFIG_SCHED_DEBUG
714 #define SCHED_FEAT(name, enabled) \
717 static __read_mostly
char *sched_feat_names
[] = {
718 #include "sched_features.h"
724 static int sched_feat_show(struct seq_file
*m
, void *v
)
728 for (i
= 0; sched_feat_names
[i
]; i
++) {
729 if (!(sysctl_sched_features
& (1UL << i
)))
731 seq_printf(m
, "%s ", sched_feat_names
[i
]);
739 sched_feat_write(struct file
*filp
, const char __user
*ubuf
,
740 size_t cnt
, loff_t
*ppos
)
750 if (copy_from_user(&buf
, ubuf
, cnt
))
755 if (strncmp(buf
, "NO_", 3) == 0) {
760 for (i
= 0; sched_feat_names
[i
]; i
++) {
761 int len
= strlen(sched_feat_names
[i
]);
763 if (strncmp(cmp
, sched_feat_names
[i
], len
) == 0) {
765 sysctl_sched_features
&= ~(1UL << i
);
767 sysctl_sched_features
|= (1UL << i
);
772 if (!sched_feat_names
[i
])
780 static int sched_feat_open(struct inode
*inode
, struct file
*filp
)
782 return single_open(filp
, sched_feat_show
, NULL
);
785 static const struct file_operations sched_feat_fops
= {
786 .open
= sched_feat_open
,
787 .write
= sched_feat_write
,
790 .release
= single_release
,
793 static __init
int sched_init_debug(void)
795 debugfs_create_file("sched_features", 0644, NULL
, NULL
,
800 late_initcall(sched_init_debug
);
804 #define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
807 * Number of tasks to iterate in a single balance run.
808 * Limited because this is done with IRQs disabled.
810 const_debug
unsigned int sysctl_sched_nr_migrate
= 32;
813 * ratelimit for updating the group shares.
816 unsigned int sysctl_sched_shares_ratelimit
= 250000;
817 unsigned int normalized_sysctl_sched_shares_ratelimit
= 250000;
820 * Inject some fuzzyness into changing the per-cpu group shares
821 * this avoids remote rq-locks at the expense of fairness.
824 unsigned int sysctl_sched_shares_thresh
= 4;
827 * period over which we average the RT time consumption, measured
832 const_debug
unsigned int sysctl_sched_time_avg
= MSEC_PER_SEC
;
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 task_rq_unlock_wait(struct task_struct
*p
)
981 struct rq
*rq
= task_rq(p
);
983 smp_mb(); /* spin-unlock-wait is not a full memory barrier */
984 spin_unlock_wait(&rq
->lock
);
987 static void __task_rq_unlock(struct rq
*rq
)
990 spin_unlock(&rq
->lock
);
993 static inline void task_rq_unlock(struct rq
*rq
, unsigned long *flags
)
996 spin_unlock_irqrestore(&rq
->lock
, *flags
);
1000 * this_rq_lock - lock this runqueue and disable interrupts.
1002 static struct rq
*this_rq_lock(void)
1003 __acquires(rq
->lock
)
1007 local_irq_disable();
1009 spin_lock(&rq
->lock
);
1014 #ifdef CONFIG_SCHED_HRTICK
1016 * Use HR-timers to deliver accurate preemption points.
1018 * Its all a bit involved since we cannot program an hrt while holding the
1019 * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
1022 * When we get rescheduled we reprogram the hrtick_timer outside of the
1028 * - enabled by features
1029 * - hrtimer is actually high res
1031 static inline int hrtick_enabled(struct rq
*rq
)
1033 if (!sched_feat(HRTICK
))
1035 if (!cpu_active(cpu_of(rq
)))
1037 return hrtimer_is_hres_active(&rq
->hrtick_timer
);
1040 static void hrtick_clear(struct rq
*rq
)
1042 if (hrtimer_active(&rq
->hrtick_timer
))
1043 hrtimer_cancel(&rq
->hrtick_timer
);
1047 * High-resolution timer tick.
1048 * Runs from hardirq context with interrupts disabled.
1050 static enum hrtimer_restart
hrtick(struct hrtimer
*timer
)
1052 struct rq
*rq
= container_of(timer
, struct rq
, hrtick_timer
);
1054 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
1056 spin_lock(&rq
->lock
);
1057 update_rq_clock(rq
);
1058 rq
->curr
->sched_class
->task_tick(rq
, rq
->curr
, 1);
1059 spin_unlock(&rq
->lock
);
1061 return HRTIMER_NORESTART
;
1066 * called from hardirq (IPI) context
1068 static void __hrtick_start(void *arg
)
1070 struct rq
*rq
= arg
;
1072 spin_lock(&rq
->lock
);
1073 hrtimer_restart(&rq
->hrtick_timer
);
1074 rq
->hrtick_csd_pending
= 0;
1075 spin_unlock(&rq
->lock
);
1079 * Called to set the hrtick timer state.
1081 * called with rq->lock held and irqs disabled
1083 static void hrtick_start(struct rq
*rq
, u64 delay
)
1085 struct hrtimer
*timer
= &rq
->hrtick_timer
;
1086 ktime_t time
= ktime_add_ns(timer
->base
->get_time(), delay
);
1088 hrtimer_set_expires(timer
, time
);
1090 if (rq
== this_rq()) {
1091 hrtimer_restart(timer
);
1092 } else if (!rq
->hrtick_csd_pending
) {
1093 __smp_call_function_single(cpu_of(rq
), &rq
->hrtick_csd
, 0);
1094 rq
->hrtick_csd_pending
= 1;
1099 hotplug_hrtick(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
1101 int cpu
= (int)(long)hcpu
;
1104 case CPU_UP_CANCELED
:
1105 case CPU_UP_CANCELED_FROZEN
:
1106 case CPU_DOWN_PREPARE
:
1107 case CPU_DOWN_PREPARE_FROZEN
:
1109 case CPU_DEAD_FROZEN
:
1110 hrtick_clear(cpu_rq(cpu
));
1117 static __init
void init_hrtick(void)
1119 hotcpu_notifier(hotplug_hrtick
, 0);
1123 * Called to set the hrtick timer state.
1125 * called with rq->lock held and irqs disabled
1127 static void hrtick_start(struct rq
*rq
, u64 delay
)
1129 __hrtimer_start_range_ns(&rq
->hrtick_timer
, ns_to_ktime(delay
), 0,
1130 HRTIMER_MODE_REL_PINNED
, 0);
1133 static inline void init_hrtick(void)
1136 #endif /* CONFIG_SMP */
1138 static void init_rq_hrtick(struct rq
*rq
)
1141 rq
->hrtick_csd_pending
= 0;
1143 rq
->hrtick_csd
.flags
= 0;
1144 rq
->hrtick_csd
.func
= __hrtick_start
;
1145 rq
->hrtick_csd
.info
= rq
;
1148 hrtimer_init(&rq
->hrtick_timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
1149 rq
->hrtick_timer
.function
= hrtick
;
1151 #else /* CONFIG_SCHED_HRTICK */
1152 static inline void hrtick_clear(struct rq
*rq
)
1156 static inline void init_rq_hrtick(struct rq
*rq
)
1160 static inline void init_hrtick(void)
1163 #endif /* CONFIG_SCHED_HRTICK */
1166 * resched_task - mark a task 'to be rescheduled now'.
1168 * On UP this means the setting of the need_resched flag, on SMP it
1169 * might also involve a cross-CPU call to trigger the scheduler on
1174 #ifndef tsk_is_polling
1175 #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
1178 static void resched_task(struct task_struct
*p
)
1182 assert_spin_locked(&task_rq(p
)->lock
);
1184 if (test_tsk_need_resched(p
))
1187 set_tsk_need_resched(p
);
1190 if (cpu
== smp_processor_id())
1193 /* NEED_RESCHED must be visible before we test polling */
1195 if (!tsk_is_polling(p
))
1196 smp_send_reschedule(cpu
);
1199 static void resched_cpu(int cpu
)
1201 struct rq
*rq
= cpu_rq(cpu
);
1202 unsigned long flags
;
1204 if (!spin_trylock_irqsave(&rq
->lock
, flags
))
1206 resched_task(cpu_curr(cpu
));
1207 spin_unlock_irqrestore(&rq
->lock
, flags
);
1212 * When add_timer_on() enqueues a timer into the timer wheel of an
1213 * idle CPU then this timer might expire before the next timer event
1214 * which is scheduled to wake up that CPU. In case of a completely
1215 * idle system the next event might even be infinite time into the
1216 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
1217 * leaves the inner idle loop so the newly added timer is taken into
1218 * account when the CPU goes back to idle and evaluates the timer
1219 * wheel for the next timer event.
1221 void wake_up_idle_cpu(int cpu
)
1223 struct rq
*rq
= cpu_rq(cpu
);
1225 if (cpu
== smp_processor_id())
1229 * This is safe, as this function is called with the timer
1230 * wheel base lock of (cpu) held. When the CPU is on the way
1231 * to idle and has not yet set rq->curr to idle then it will
1232 * be serialized on the timer wheel base lock and take the new
1233 * timer into account automatically.
1235 if (rq
->curr
!= rq
->idle
)
1239 * We can set TIF_RESCHED on the idle task of the other CPU
1240 * lockless. The worst case is that the other CPU runs the
1241 * idle task through an additional NOOP schedule()
1243 set_tsk_need_resched(rq
->idle
);
1245 /* NEED_RESCHED must be visible before we test polling */
1247 if (!tsk_is_polling(rq
->idle
))
1248 smp_send_reschedule(cpu
);
1250 #endif /* CONFIG_NO_HZ */
1252 static u64
sched_avg_period(void)
1254 return (u64
)sysctl_sched_time_avg
* NSEC_PER_MSEC
/ 2;
1257 static void sched_avg_update(struct rq
*rq
)
1259 s64 period
= sched_avg_period();
1261 while ((s64
)(rq
->clock
- rq
->age_stamp
) > period
) {
1262 rq
->age_stamp
+= period
;
1267 static void sched_rt_avg_update(struct rq
*rq
, u64 rt_delta
)
1269 rq
->rt_avg
+= rt_delta
;
1270 sched_avg_update(rq
);
1273 #else /* !CONFIG_SMP */
1274 static void resched_task(struct task_struct
*p
)
1276 assert_spin_locked(&task_rq(p
)->lock
);
1277 set_tsk_need_resched(p
);
1280 static void sched_rt_avg_update(struct rq
*rq
, u64 rt_delta
)
1283 #endif /* CONFIG_SMP */
1285 #if BITS_PER_LONG == 32
1286 # define WMULT_CONST (~0UL)
1288 # define WMULT_CONST (1UL << 32)
1291 #define WMULT_SHIFT 32
1294 * Shift right and round:
1296 #define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y))
1299 * delta *= weight / lw
1301 static unsigned long
1302 calc_delta_mine(unsigned long delta_exec
, unsigned long weight
,
1303 struct load_weight
*lw
)
1307 if (!lw
->inv_weight
) {
1308 if (BITS_PER_LONG
> 32 && unlikely(lw
->weight
>= WMULT_CONST
))
1311 lw
->inv_weight
= 1 + (WMULT_CONST
-lw
->weight
/2)
1315 tmp
= (u64
)delta_exec
* weight
;
1317 * Check whether we'd overflow the 64-bit multiplication:
1319 if (unlikely(tmp
> WMULT_CONST
))
1320 tmp
= SRR(SRR(tmp
, WMULT_SHIFT
/2) * lw
->inv_weight
,
1323 tmp
= SRR(tmp
* lw
->inv_weight
, WMULT_SHIFT
);
1325 return (unsigned long)min(tmp
, (u64
)(unsigned long)LONG_MAX
);
1328 static inline void update_load_add(struct load_weight
*lw
, unsigned long inc
)
1334 static inline void update_load_sub(struct load_weight
*lw
, unsigned long dec
)
1341 * To aid in avoiding the subversion of "niceness" due to uneven distribution
1342 * of tasks with abnormal "nice" values across CPUs the contribution that
1343 * each task makes to its run queue's load is weighted according to its
1344 * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
1345 * scaled version of the new time slice allocation that they receive on time
1349 #define WEIGHT_IDLEPRIO 3
1350 #define WMULT_IDLEPRIO 1431655765
1353 * Nice levels are multiplicative, with a gentle 10% change for every
1354 * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
1355 * nice 1, it will get ~10% less CPU time than another CPU-bound task
1356 * that remained on nice 0.
1358 * The "10% effect" is relative and cumulative: from _any_ nice level,
1359 * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
1360 * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
1361 * If a task goes up by ~10% and another task goes down by ~10% then
1362 * the relative distance between them is ~25%.)
1364 static const int prio_to_weight
[40] = {
1365 /* -20 */ 88761, 71755, 56483, 46273, 36291,
1366 /* -15 */ 29154, 23254, 18705, 14949, 11916,
1367 /* -10 */ 9548, 7620, 6100, 4904, 3906,
1368 /* -5 */ 3121, 2501, 1991, 1586, 1277,
1369 /* 0 */ 1024, 820, 655, 526, 423,
1370 /* 5 */ 335, 272, 215, 172, 137,
1371 /* 10 */ 110, 87, 70, 56, 45,
1372 /* 15 */ 36, 29, 23, 18, 15,
1376 * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated.
1378 * In cases where the weight does not change often, we can use the
1379 * precalculated inverse to speed up arithmetics by turning divisions
1380 * into multiplications:
1382 static const u32 prio_to_wmult
[40] = {
1383 /* -20 */ 48388, 59856, 76040, 92818, 118348,
1384 /* -15 */ 147320, 184698, 229616, 287308, 360437,
1385 /* -10 */ 449829, 563644, 704093, 875809, 1099582,
1386 /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326,
1387 /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587,
1388 /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126,
1389 /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717,
1390 /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
1393 static void activate_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
);
1396 * runqueue iterator, to support SMP load-balancing between different
1397 * scheduling classes, without having to expose their internal data
1398 * structures to the load-balancing proper:
1400 struct rq_iterator
{
1402 struct task_struct
*(*start
)(void *);
1403 struct task_struct
*(*next
)(void *);
1407 static unsigned long
1408 balance_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
1409 unsigned long max_load_move
, struct sched_domain
*sd
,
1410 enum cpu_idle_type idle
, int *all_pinned
,
1411 int *this_best_prio
, struct rq_iterator
*iterator
);
1414 iter_move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
1415 struct sched_domain
*sd
, enum cpu_idle_type idle
,
1416 struct rq_iterator
*iterator
);
1419 /* Time spent by the tasks of the cpu accounting group executing in ... */
1420 enum cpuacct_stat_index
{
1421 CPUACCT_STAT_USER
, /* ... user mode */
1422 CPUACCT_STAT_SYSTEM
, /* ... kernel mode */
1424 CPUACCT_STAT_NSTATS
,
1427 #ifdef CONFIG_CGROUP_CPUACCT
1428 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
);
1429 static void cpuacct_update_stats(struct task_struct
*tsk
,
1430 enum cpuacct_stat_index idx
, cputime_t val
);
1432 static inline void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
) {}
1433 static inline void cpuacct_update_stats(struct task_struct
*tsk
,
1434 enum cpuacct_stat_index idx
, cputime_t val
) {}
1437 static inline void inc_cpu_load(struct rq
*rq
, unsigned long load
)
1439 update_load_add(&rq
->load
, load
);
1442 static inline void dec_cpu_load(struct rq
*rq
, unsigned long load
)
1444 update_load_sub(&rq
->load
, load
);
1447 #if (defined(CONFIG_SMP) && defined(CONFIG_FAIR_GROUP_SCHED)) || defined(CONFIG_RT_GROUP_SCHED)
1448 typedef int (*tg_visitor
)(struct task_group
*, void *);
1451 * Iterate the full tree, calling @down when first entering a node and @up when
1452 * leaving it for the final time.
1454 static int walk_tg_tree(tg_visitor down
, tg_visitor up
, void *data
)
1456 struct task_group
*parent
, *child
;
1460 parent
= &root_task_group
;
1462 ret
= (*down
)(parent
, data
);
1465 list_for_each_entry_rcu(child
, &parent
->children
, siblings
) {
1472 ret
= (*up
)(parent
, data
);
1477 parent
= parent
->parent
;
1486 static int tg_nop(struct task_group
*tg
, void *data
)
1493 /* Used instead of source_load when we know the type == 0 */
1494 static unsigned long weighted_cpuload(const int cpu
)
1496 return cpu_rq(cpu
)->load
.weight
;
1500 * Return a low guess at the load of a migration-source cpu weighted
1501 * according to the scheduling class and "nice" value.
1503 * We want to under-estimate the load of migration sources, to
1504 * balance conservatively.
1506 static unsigned long source_load(int cpu
, int type
)
1508 struct rq
*rq
= cpu_rq(cpu
);
1509 unsigned long total
= weighted_cpuload(cpu
);
1511 if (type
== 0 || !sched_feat(LB_BIAS
))
1514 return min(rq
->cpu_load
[type
-1], total
);
1518 * Return a high guess at the load of a migration-target cpu weighted
1519 * according to the scheduling class and "nice" value.
1521 static unsigned long target_load(int cpu
, int type
)
1523 struct rq
*rq
= cpu_rq(cpu
);
1524 unsigned long total
= weighted_cpuload(cpu
);
1526 if (type
== 0 || !sched_feat(LB_BIAS
))
1529 return max(rq
->cpu_load
[type
-1], total
);
1532 static struct sched_group
*group_of(int cpu
)
1534 struct sched_domain
*sd
= rcu_dereference(cpu_rq(cpu
)->sd
);
1542 static unsigned long power_of(int cpu
)
1544 struct sched_group
*group
= group_of(cpu
);
1547 return SCHED_LOAD_SCALE
;
1549 return group
->cpu_power
;
1552 static int task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
);
1554 static unsigned long cpu_avg_load_per_task(int cpu
)
1556 struct rq
*rq
= cpu_rq(cpu
);
1557 unsigned long nr_running
= ACCESS_ONCE(rq
->nr_running
);
1560 rq
->avg_load_per_task
= rq
->load
.weight
/ nr_running
;
1562 rq
->avg_load_per_task
= 0;
1564 return rq
->avg_load_per_task
;
1567 #ifdef CONFIG_FAIR_GROUP_SCHED
1569 static __read_mostly
unsigned long *update_shares_data
;
1571 static void __set_se_shares(struct sched_entity
*se
, unsigned long shares
);
1574 * Calculate and set the cpu's group shares.
1576 static void update_group_shares_cpu(struct task_group
*tg
, int cpu
,
1577 unsigned long sd_shares
,
1578 unsigned long sd_rq_weight
,
1579 unsigned long *usd_rq_weight
)
1581 unsigned long shares
, rq_weight
;
1584 rq_weight
= usd_rq_weight
[cpu
];
1587 rq_weight
= NICE_0_LOAD
;
1591 * \Sum_j shares_j * rq_weight_i
1592 * shares_i = -----------------------------
1593 * \Sum_j rq_weight_j
1595 shares
= (sd_shares
* rq_weight
) / sd_rq_weight
;
1596 shares
= clamp_t(unsigned long, shares
, MIN_SHARES
, MAX_SHARES
);
1598 if (abs(shares
- tg
->se
[cpu
]->load
.weight
) >
1599 sysctl_sched_shares_thresh
) {
1600 struct rq
*rq
= cpu_rq(cpu
);
1601 unsigned long flags
;
1603 spin_lock_irqsave(&rq
->lock
, flags
);
1604 tg
->cfs_rq
[cpu
]->rq_weight
= boost
? 0 : rq_weight
;
1605 tg
->cfs_rq
[cpu
]->shares
= boost
? 0 : shares
;
1606 __set_se_shares(tg
->se
[cpu
], shares
);
1607 spin_unlock_irqrestore(&rq
->lock
, flags
);
1612 * Re-compute the task group their per cpu shares over the given domain.
1613 * This needs to be done in a bottom-up fashion because the rq weight of a
1614 * parent group depends on the shares of its child groups.
1616 static int tg_shares_up(struct task_group
*tg
, void *data
)
1618 unsigned long weight
, rq_weight
= 0, sum_weight
= 0, shares
= 0;
1619 unsigned long *usd_rq_weight
;
1620 struct sched_domain
*sd
= data
;
1621 unsigned long flags
;
1627 local_irq_save(flags
);
1628 usd_rq_weight
= per_cpu_ptr(update_shares_data
, smp_processor_id());
1630 for_each_cpu(i
, sched_domain_span(sd
)) {
1631 weight
= tg
->cfs_rq
[i
]->load
.weight
;
1632 usd_rq_weight
[i
] = weight
;
1634 rq_weight
+= weight
;
1636 * If there are currently no tasks on the cpu pretend there
1637 * is one of average load so that when a new task gets to
1638 * run here it will not get delayed by group starvation.
1641 weight
= NICE_0_LOAD
;
1643 sum_weight
+= weight
;
1644 shares
+= tg
->cfs_rq
[i
]->shares
;
1648 rq_weight
= sum_weight
;
1650 if ((!shares
&& rq_weight
) || shares
> tg
->shares
)
1651 shares
= tg
->shares
;
1653 if (!sd
->parent
|| !(sd
->parent
->flags
& SD_LOAD_BALANCE
))
1654 shares
= tg
->shares
;
1656 for_each_cpu(i
, sched_domain_span(sd
))
1657 update_group_shares_cpu(tg
, i
, shares
, rq_weight
, usd_rq_weight
);
1659 local_irq_restore(flags
);
1665 * Compute the cpu's hierarchical load factor for each task group.
1666 * This needs to be done in a top-down fashion because the load of a child
1667 * group is a fraction of its parents load.
1669 static int tg_load_down(struct task_group
*tg
, void *data
)
1672 long cpu
= (long)data
;
1675 load
= cpu_rq(cpu
)->load
.weight
;
1677 load
= tg
->parent
->cfs_rq
[cpu
]->h_load
;
1678 load
*= tg
->cfs_rq
[cpu
]->shares
;
1679 load
/= tg
->parent
->cfs_rq
[cpu
]->load
.weight
+ 1;
1682 tg
->cfs_rq
[cpu
]->h_load
= load
;
1687 static void update_shares(struct sched_domain
*sd
)
1692 if (root_task_group_empty())
1695 now
= cpu_clock(raw_smp_processor_id());
1696 elapsed
= now
- sd
->last_update
;
1698 if (elapsed
>= (s64
)(u64
)sysctl_sched_shares_ratelimit
) {
1699 sd
->last_update
= now
;
1700 walk_tg_tree(tg_nop
, tg_shares_up
, sd
);
1704 static void update_shares_locked(struct rq
*rq
, struct sched_domain
*sd
)
1706 if (root_task_group_empty())
1709 spin_unlock(&rq
->lock
);
1711 spin_lock(&rq
->lock
);
1714 static void update_h_load(long cpu
)
1716 if (root_task_group_empty())
1719 walk_tg_tree(tg_load_down
, tg_nop
, (void *)cpu
);
1724 static inline void update_shares(struct sched_domain
*sd
)
1728 static inline void update_shares_locked(struct rq
*rq
, struct sched_domain
*sd
)
1734 #ifdef CONFIG_PREEMPT
1736 static void double_rq_lock(struct rq
*rq1
, struct rq
*rq2
);
1739 * fair double_lock_balance: Safely acquires both rq->locks in a fair
1740 * way at the expense of forcing extra atomic operations in all
1741 * invocations. This assures that the double_lock is acquired using the
1742 * same underlying policy as the spinlock_t on this architecture, which
1743 * reduces latency compared to the unfair variant below. However, it
1744 * also adds more overhead and therefore may reduce throughput.
1746 static inline int _double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1747 __releases(this_rq
->lock
)
1748 __acquires(busiest
->lock
)
1749 __acquires(this_rq
->lock
)
1751 spin_unlock(&this_rq
->lock
);
1752 double_rq_lock(this_rq
, busiest
);
1759 * Unfair double_lock_balance: Optimizes throughput at the expense of
1760 * latency by eliminating extra atomic operations when the locks are
1761 * already in proper order on entry. This favors lower cpu-ids and will
1762 * grant the double lock to lower cpus over higher ids under contention,
1763 * regardless of entry order into the function.
1765 static int _double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1766 __releases(this_rq
->lock
)
1767 __acquires(busiest
->lock
)
1768 __acquires(this_rq
->lock
)
1772 if (unlikely(!spin_trylock(&busiest
->lock
))) {
1773 if (busiest
< this_rq
) {
1774 spin_unlock(&this_rq
->lock
);
1775 spin_lock(&busiest
->lock
);
1776 spin_lock_nested(&this_rq
->lock
, SINGLE_DEPTH_NESTING
);
1779 spin_lock_nested(&busiest
->lock
, SINGLE_DEPTH_NESTING
);
1784 #endif /* CONFIG_PREEMPT */
1787 * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
1789 static int double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1791 if (unlikely(!irqs_disabled())) {
1792 /* printk() doesn't work good under rq->lock */
1793 spin_unlock(&this_rq
->lock
);
1797 return _double_lock_balance(this_rq
, busiest
);
1800 static inline void double_unlock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1801 __releases(busiest
->lock
)
1803 spin_unlock(&busiest
->lock
);
1804 lock_set_subclass(&this_rq
->lock
.dep_map
, 0, _RET_IP_
);
1808 #ifdef CONFIG_FAIR_GROUP_SCHED
1809 static void cfs_rq_set_shares(struct cfs_rq
*cfs_rq
, unsigned long shares
)
1812 cfs_rq
->shares
= shares
;
1817 static void calc_load_account_active(struct rq
*this_rq
);
1818 static void update_sysctl(void);
1820 static inline void __set_task_cpu(struct task_struct
*p
, unsigned int cpu
)
1822 set_task_rq(p
, cpu
);
1825 * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be
1826 * successfuly executed on another CPU. We must ensure that updates of
1827 * per-task data have been completed by this moment.
1830 task_thread_info(p
)->cpu
= cpu
;
1834 #include "sched_stats.h"
1835 #include "sched_idletask.c"
1836 #include "sched_fair.c"
1837 #include "sched_rt.c"
1838 #ifdef CONFIG_SCHED_DEBUG
1839 # include "sched_debug.c"
1842 #define sched_class_highest (&rt_sched_class)
1843 #define for_each_class(class) \
1844 for (class = sched_class_highest; class; class = class->next)
1846 static void inc_nr_running(struct rq
*rq
)
1851 static void dec_nr_running(struct rq
*rq
)
1856 static void set_load_weight(struct task_struct
*p
)
1858 if (task_has_rt_policy(p
)) {
1859 p
->se
.load
.weight
= prio_to_weight
[0] * 2;
1860 p
->se
.load
.inv_weight
= prio_to_wmult
[0] >> 1;
1865 * SCHED_IDLE tasks get minimal weight:
1867 if (p
->policy
== SCHED_IDLE
) {
1868 p
->se
.load
.weight
= WEIGHT_IDLEPRIO
;
1869 p
->se
.load
.inv_weight
= WMULT_IDLEPRIO
;
1873 p
->se
.load
.weight
= prio_to_weight
[p
->static_prio
- MAX_RT_PRIO
];
1874 p
->se
.load
.inv_weight
= prio_to_wmult
[p
->static_prio
- MAX_RT_PRIO
];
1877 static void update_avg(u64
*avg
, u64 sample
)
1879 s64 diff
= sample
- *avg
;
1883 static void enqueue_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
)
1886 p
->se
.start_runtime
= p
->se
.sum_exec_runtime
;
1888 sched_info_queued(p
);
1889 p
->sched_class
->enqueue_task(rq
, p
, wakeup
);
1893 static void dequeue_task(struct rq
*rq
, struct task_struct
*p
, int sleep
)
1896 if (p
->se
.last_wakeup
) {
1897 update_avg(&p
->se
.avg_overlap
,
1898 p
->se
.sum_exec_runtime
- p
->se
.last_wakeup
);
1899 p
->se
.last_wakeup
= 0;
1901 update_avg(&p
->se
.avg_wakeup
,
1902 sysctl_sched_wakeup_granularity
);
1906 sched_info_dequeued(p
);
1907 p
->sched_class
->dequeue_task(rq
, p
, sleep
);
1912 * __normal_prio - return the priority that is based on the static prio
1914 static inline int __normal_prio(struct task_struct
*p
)
1916 return p
->static_prio
;
1920 * Calculate the expected normal priority: i.e. priority
1921 * without taking RT-inheritance into account. Might be
1922 * boosted by interactivity modifiers. Changes upon fork,
1923 * setprio syscalls, and whenever the interactivity
1924 * estimator recalculates.
1926 static inline int normal_prio(struct task_struct
*p
)
1930 if (task_has_rt_policy(p
))
1931 prio
= MAX_RT_PRIO
-1 - p
->rt_priority
;
1933 prio
= __normal_prio(p
);
1938 * Calculate the current priority, i.e. the priority
1939 * taken into account by the scheduler. This value might
1940 * be boosted by RT tasks, or might be boosted by
1941 * interactivity modifiers. Will be RT if the task got
1942 * RT-boosted. If not then it returns p->normal_prio.
1944 static int effective_prio(struct task_struct
*p
)
1946 p
->normal_prio
= normal_prio(p
);
1948 * If we are RT tasks or we were boosted to RT priority,
1949 * keep the priority unchanged. Otherwise, update priority
1950 * to the normal priority:
1952 if (!rt_prio(p
->prio
))
1953 return p
->normal_prio
;
1958 * activate_task - move a task to the runqueue.
1960 static void activate_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
)
1962 if (task_contributes_to_load(p
))
1963 rq
->nr_uninterruptible
--;
1965 enqueue_task(rq
, p
, wakeup
);
1970 * deactivate_task - remove a task from the runqueue.
1972 static void deactivate_task(struct rq
*rq
, struct task_struct
*p
, int sleep
)
1974 if (task_contributes_to_load(p
))
1975 rq
->nr_uninterruptible
++;
1977 dequeue_task(rq
, p
, sleep
);
1982 * task_curr - is this task currently executing on a CPU?
1983 * @p: the task in question.
1985 inline int task_curr(const struct task_struct
*p
)
1987 return cpu_curr(task_cpu(p
)) == p
;
1990 static inline void check_class_changed(struct rq
*rq
, struct task_struct
*p
,
1991 const struct sched_class
*prev_class
,
1992 int oldprio
, int running
)
1994 if (prev_class
!= p
->sched_class
) {
1995 if (prev_class
->switched_from
)
1996 prev_class
->switched_from(rq
, p
, running
);
1997 p
->sched_class
->switched_to(rq
, p
, running
);
1999 p
->sched_class
->prio_changed(rq
, p
, oldprio
, running
);
2003 * kthread_bind - bind a just-created kthread to a cpu.
2004 * @p: thread created by kthread_create().
2005 * @cpu: cpu (might not be online, must be possible) for @k to run on.
2007 * Description: This function is equivalent to set_cpus_allowed(),
2008 * except that @cpu doesn't need to be online, and the thread must be
2009 * stopped (i.e., just returned from kthread_create()).
2011 * Function lives here instead of kthread.c because it messes with
2012 * scheduler internals which require locking.
2014 void kthread_bind(struct task_struct
*p
, unsigned int cpu
)
2016 struct rq
*rq
= cpu_rq(cpu
);
2017 unsigned long flags
;
2019 /* Must have done schedule() in kthread() before we set_task_cpu */
2020 if (!wait_task_inactive(p
, TASK_UNINTERRUPTIBLE
)) {
2025 spin_lock_irqsave(&rq
->lock
, flags
);
2026 update_rq_clock(rq
);
2027 set_task_cpu(p
, cpu
);
2028 p
->cpus_allowed
= cpumask_of_cpu(cpu
);
2029 p
->rt
.nr_cpus_allowed
= 1;
2030 p
->flags
|= PF_THREAD_BOUND
;
2031 spin_unlock_irqrestore(&rq
->lock
, flags
);
2033 EXPORT_SYMBOL(kthread_bind
);
2037 * Is this task likely cache-hot:
2040 task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
)
2045 * Buddy candidates are cache hot:
2047 if (sched_feat(CACHE_HOT_BUDDY
) && this_rq()->nr_running
&&
2048 (&p
->se
== cfs_rq_of(&p
->se
)->next
||
2049 &p
->se
== cfs_rq_of(&p
->se
)->last
))
2052 if (p
->sched_class
!= &fair_sched_class
)
2055 if (sysctl_sched_migration_cost
== -1)
2057 if (sysctl_sched_migration_cost
== 0)
2060 delta
= now
- p
->se
.exec_start
;
2062 return delta
< (s64
)sysctl_sched_migration_cost
;
2066 void set_task_cpu(struct task_struct
*p
, unsigned int new_cpu
)
2068 int old_cpu
= task_cpu(p
);
2069 struct rq
*old_rq
= cpu_rq(old_cpu
);
2070 struct cfs_rq
*old_cfsrq
= task_cfs_rq(p
),
2071 *new_cfsrq
= cpu_cfs_rq(old_cfsrq
, new_cpu
);
2073 trace_sched_migrate_task(p
, new_cpu
);
2075 if (old_cpu
!= new_cpu
) {
2076 p
->se
.nr_migrations
++;
2077 #ifdef CONFIG_SCHEDSTATS
2078 if (task_hot(p
, old_rq
->clock
, NULL
))
2079 schedstat_inc(p
, se
.nr_forced2_migrations
);
2081 perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS
,
2084 p
->se
.vruntime
-= old_cfsrq
->min_vruntime
-
2085 new_cfsrq
->min_vruntime
;
2087 __set_task_cpu(p
, new_cpu
);
2090 struct migration_req
{
2091 struct list_head list
;
2093 struct task_struct
*task
;
2096 struct completion done
;
2100 * The task's runqueue lock must be held.
2101 * Returns true if you have to wait for migration thread.
2104 migrate_task(struct task_struct
*p
, int dest_cpu
, struct migration_req
*req
)
2106 struct rq
*rq
= task_rq(p
);
2109 * If the task is not on a runqueue (and not running), then
2110 * it is sufficient to simply update the task's cpu field.
2112 if (!p
->se
.on_rq
&& !task_running(rq
, p
)) {
2113 update_rq_clock(rq
);
2114 set_task_cpu(p
, dest_cpu
);
2118 init_completion(&req
->done
);
2120 req
->dest_cpu
= dest_cpu
;
2121 list_add(&req
->list
, &rq
->migration_queue
);
2127 * wait_task_context_switch - wait for a thread to complete at least one
2130 * @p must not be current.
2132 void wait_task_context_switch(struct task_struct
*p
)
2134 unsigned long nvcsw
, nivcsw
, flags
;
2142 * The runqueue is assigned before the actual context
2143 * switch. We need to take the runqueue lock.
2145 * We could check initially without the lock but it is
2146 * very likely that we need to take the lock in every
2149 rq
= task_rq_lock(p
, &flags
);
2150 running
= task_running(rq
, p
);
2151 task_rq_unlock(rq
, &flags
);
2153 if (likely(!running
))
2156 * The switch count is incremented before the actual
2157 * context switch. We thus wait for two switches to be
2158 * sure at least one completed.
2160 if ((p
->nvcsw
- nvcsw
) > 1)
2162 if ((p
->nivcsw
- nivcsw
) > 1)
2170 * wait_task_inactive - wait for a thread to unschedule.
2172 * If @match_state is nonzero, it's the @p->state value just checked and
2173 * not expected to change. If it changes, i.e. @p might have woken up,
2174 * then return zero. When we succeed in waiting for @p to be off its CPU,
2175 * we return a positive number (its total switch count). If a second call
2176 * a short while later returns the same number, the caller can be sure that
2177 * @p has remained unscheduled the whole time.
2179 * The caller must ensure that the task *will* unschedule sometime soon,
2180 * else this function might spin for a *long* time. This function can't
2181 * be called with interrupts off, or it may introduce deadlock with
2182 * smp_call_function() if an IPI is sent by the same process we are
2183 * waiting to become inactive.
2185 unsigned long wait_task_inactive(struct task_struct
*p
, long match_state
)
2187 unsigned long flags
;
2194 * We do the initial early heuristics without holding
2195 * any task-queue locks at all. We'll only try to get
2196 * the runqueue lock when things look like they will
2202 * If the task is actively running on another CPU
2203 * still, just relax and busy-wait without holding
2206 * NOTE! Since we don't hold any locks, it's not
2207 * even sure that "rq" stays as the right runqueue!
2208 * But we don't care, since "task_running()" will
2209 * return false if the runqueue has changed and p
2210 * is actually now running somewhere else!
2212 while (task_running(rq
, p
)) {
2213 if (match_state
&& unlikely(p
->state
!= match_state
))
2219 * Ok, time to look more closely! We need the rq
2220 * lock now, to be *sure*. If we're wrong, we'll
2221 * just go back and repeat.
2223 rq
= task_rq_lock(p
, &flags
);
2224 trace_sched_wait_task(rq
, p
);
2225 running
= task_running(rq
, p
);
2226 on_rq
= p
->se
.on_rq
;
2228 if (!match_state
|| p
->state
== match_state
)
2229 ncsw
= p
->nvcsw
| LONG_MIN
; /* sets MSB */
2230 task_rq_unlock(rq
, &flags
);
2233 * If it changed from the expected state, bail out now.
2235 if (unlikely(!ncsw
))
2239 * Was it really running after all now that we
2240 * checked with the proper locks actually held?
2242 * Oops. Go back and try again..
2244 if (unlikely(running
)) {
2250 * It's not enough that it's not actively running,
2251 * it must be off the runqueue _entirely_, and not
2254 * So if it was still runnable (but just not actively
2255 * running right now), it's preempted, and we should
2256 * yield - it could be a while.
2258 if (unlikely(on_rq
)) {
2259 schedule_timeout_uninterruptible(1);
2264 * Ahh, all good. It wasn't running, and it wasn't
2265 * runnable, which means that it will never become
2266 * running in the future either. We're all done!
2275 * kick_process - kick a running thread to enter/exit the kernel
2276 * @p: the to-be-kicked thread
2278 * Cause a process which is running on another CPU to enter
2279 * kernel-mode, without any delay. (to get signals handled.)
2281 * NOTE: this function doesnt have to take the runqueue lock,
2282 * because all it wants to ensure is that the remote task enters
2283 * the kernel. If the IPI races and the task has been migrated
2284 * to another CPU then no harm is done and the purpose has been
2287 void kick_process(struct task_struct
*p
)
2293 if ((cpu
!= smp_processor_id()) && task_curr(p
))
2294 smp_send_reschedule(cpu
);
2297 EXPORT_SYMBOL_GPL(kick_process
);
2298 #endif /* CONFIG_SMP */
2301 * task_oncpu_function_call - call a function on the cpu on which a task runs
2302 * @p: the task to evaluate
2303 * @func: the function to be called
2304 * @info: the function call argument
2306 * Calls the function @func when the task is currently running. This might
2307 * be on the current CPU, which just calls the function directly
2309 void task_oncpu_function_call(struct task_struct
*p
,
2310 void (*func
) (void *info
), void *info
)
2317 smp_call_function_single(cpu
, func
, info
, 1);
2323 int select_task_rq(struct task_struct
*p
, int sd_flags
, int wake_flags
)
2325 return p
->sched_class
->select_task_rq(p
, sd_flags
, wake_flags
);
2330 * try_to_wake_up - wake up a thread
2331 * @p: the to-be-woken-up thread
2332 * @state: the mask of task states that can be woken
2333 * @sync: do a synchronous wakeup?
2335 * Put it on the run-queue if it's not already there. The "current"
2336 * thread is always on the run-queue (except when the actual
2337 * re-schedule is in progress), and as such you're allowed to do
2338 * the simpler "current->state = TASK_RUNNING" to mark yourself
2339 * runnable without the overhead of this.
2341 * returns failure only if the task is already active.
2343 static int try_to_wake_up(struct task_struct
*p
, unsigned int state
,
2346 int cpu
, orig_cpu
, this_cpu
, success
= 0;
2347 unsigned long flags
;
2348 struct rq
*rq
, *orig_rq
;
2350 if (!sched_feat(SYNC_WAKEUPS
))
2351 wake_flags
&= ~WF_SYNC
;
2353 this_cpu
= get_cpu();
2356 rq
= orig_rq
= task_rq_lock(p
, &flags
);
2357 update_rq_clock(rq
);
2358 if (!(p
->state
& state
))
2368 if (unlikely(task_running(rq
, p
)))
2372 * In order to handle concurrent wakeups and release the rq->lock
2373 * we put the task in TASK_WAKING state.
2375 * First fix up the nr_uninterruptible count:
2377 if (task_contributes_to_load(p
))
2378 rq
->nr_uninterruptible
--;
2379 p
->state
= TASK_WAKING
;
2380 __task_rq_unlock(rq
);
2382 cpu
= select_task_rq(p
, SD_BALANCE_WAKE
, wake_flags
);
2383 if (cpu
!= orig_cpu
)
2384 set_task_cpu(p
, cpu
);
2386 rq
= __task_rq_lock(p
);
2387 update_rq_clock(rq
);
2389 WARN_ON(p
->state
!= TASK_WAKING
);
2392 #ifdef CONFIG_SCHEDSTATS
2393 schedstat_inc(rq
, ttwu_count
);
2394 if (cpu
== this_cpu
)
2395 schedstat_inc(rq
, ttwu_local
);
2397 struct sched_domain
*sd
;
2398 for_each_domain(this_cpu
, sd
) {
2399 if (cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
2400 schedstat_inc(sd
, ttwu_wake_remote
);
2405 #endif /* CONFIG_SCHEDSTATS */
2408 #endif /* CONFIG_SMP */
2409 schedstat_inc(p
, se
.nr_wakeups
);
2410 if (wake_flags
& WF_SYNC
)
2411 schedstat_inc(p
, se
.nr_wakeups_sync
);
2412 if (orig_cpu
!= cpu
)
2413 schedstat_inc(p
, se
.nr_wakeups_migrate
);
2414 if (cpu
== this_cpu
)
2415 schedstat_inc(p
, se
.nr_wakeups_local
);
2417 schedstat_inc(p
, se
.nr_wakeups_remote
);
2418 activate_task(rq
, p
, 1);
2422 * Only attribute actual wakeups done by this task.
2424 if (!in_interrupt()) {
2425 struct sched_entity
*se
= ¤t
->se
;
2426 u64 sample
= se
->sum_exec_runtime
;
2428 if (se
->last_wakeup
)
2429 sample
-= se
->last_wakeup
;
2431 sample
-= se
->start_runtime
;
2432 update_avg(&se
->avg_wakeup
, sample
);
2434 se
->last_wakeup
= se
->sum_exec_runtime
;
2438 trace_sched_wakeup(rq
, p
, success
);
2439 check_preempt_curr(rq
, p
, wake_flags
);
2441 p
->state
= TASK_RUNNING
;
2443 if (p
->sched_class
->task_wake_up
)
2444 p
->sched_class
->task_wake_up(rq
, p
);
2446 if (unlikely(rq
->idle_stamp
)) {
2447 u64 delta
= rq
->clock
- rq
->idle_stamp
;
2448 u64 max
= 2*sysctl_sched_migration_cost
;
2453 update_avg(&rq
->avg_idle
, delta
);
2458 task_rq_unlock(rq
, &flags
);
2465 * wake_up_process - Wake up a specific process
2466 * @p: The process to be woken up.
2468 * Attempt to wake up the nominated process and move it to the set of runnable
2469 * processes. Returns 1 if the process was woken up, 0 if it was already
2472 * It may be assumed that this function implies a write memory barrier before
2473 * changing the task state if and only if any tasks are woken up.
2475 int wake_up_process(struct task_struct
*p
)
2477 return try_to_wake_up(p
, TASK_ALL
, 0);
2479 EXPORT_SYMBOL(wake_up_process
);
2481 int wake_up_state(struct task_struct
*p
, unsigned int state
)
2483 return try_to_wake_up(p
, state
, 0);
2487 * Perform scheduler related setup for a newly forked process p.
2488 * p is forked by current.
2490 * __sched_fork() is basic setup used by init_idle() too:
2492 static void __sched_fork(struct task_struct
*p
)
2494 p
->se
.exec_start
= 0;
2495 p
->se
.sum_exec_runtime
= 0;
2496 p
->se
.prev_sum_exec_runtime
= 0;
2497 p
->se
.nr_migrations
= 0;
2498 p
->se
.last_wakeup
= 0;
2499 p
->se
.avg_overlap
= 0;
2500 p
->se
.start_runtime
= 0;
2501 p
->se
.avg_wakeup
= sysctl_sched_wakeup_granularity
;
2503 #ifdef CONFIG_SCHEDSTATS
2504 p
->se
.wait_start
= 0;
2506 p
->se
.wait_count
= 0;
2509 p
->se
.sleep_start
= 0;
2510 p
->se
.sleep_max
= 0;
2511 p
->se
.sum_sleep_runtime
= 0;
2513 p
->se
.block_start
= 0;
2514 p
->se
.block_max
= 0;
2516 p
->se
.slice_max
= 0;
2518 p
->se
.nr_migrations_cold
= 0;
2519 p
->se
.nr_failed_migrations_affine
= 0;
2520 p
->se
.nr_failed_migrations_running
= 0;
2521 p
->se
.nr_failed_migrations_hot
= 0;
2522 p
->se
.nr_forced_migrations
= 0;
2523 p
->se
.nr_forced2_migrations
= 0;
2525 p
->se
.nr_wakeups
= 0;
2526 p
->se
.nr_wakeups_sync
= 0;
2527 p
->se
.nr_wakeups_migrate
= 0;
2528 p
->se
.nr_wakeups_local
= 0;
2529 p
->se
.nr_wakeups_remote
= 0;
2530 p
->se
.nr_wakeups_affine
= 0;
2531 p
->se
.nr_wakeups_affine_attempts
= 0;
2532 p
->se
.nr_wakeups_passive
= 0;
2533 p
->se
.nr_wakeups_idle
= 0;
2537 INIT_LIST_HEAD(&p
->rt
.run_list
);
2539 INIT_LIST_HEAD(&p
->se
.group_node
);
2541 #ifdef CONFIG_PREEMPT_NOTIFIERS
2542 INIT_HLIST_HEAD(&p
->preempt_notifiers
);
2546 * We mark the process as running here, but have not actually
2547 * inserted it onto the runqueue yet. This guarantees that
2548 * nobody will actually run it, and a signal or other external
2549 * event cannot wake it up and insert it on the runqueue either.
2551 p
->state
= TASK_RUNNING
;
2555 * fork()/clone()-time setup:
2557 void sched_fork(struct task_struct
*p
, int clone_flags
)
2559 int cpu
= get_cpu();
2564 * Revert to default priority/policy on fork if requested.
2566 if (unlikely(p
->sched_reset_on_fork
)) {
2567 if (p
->policy
== SCHED_FIFO
|| p
->policy
== SCHED_RR
) {
2568 p
->policy
= SCHED_NORMAL
;
2569 p
->normal_prio
= p
->static_prio
;
2572 if (PRIO_TO_NICE(p
->static_prio
) < 0) {
2573 p
->static_prio
= NICE_TO_PRIO(0);
2574 p
->normal_prio
= p
->static_prio
;
2579 * We don't need the reset flag anymore after the fork. It has
2580 * fulfilled its duty:
2582 p
->sched_reset_on_fork
= 0;
2586 * Make sure we do not leak PI boosting priority to the child.
2588 p
->prio
= current
->normal_prio
;
2590 if (!rt_prio(p
->prio
))
2591 p
->sched_class
= &fair_sched_class
;
2593 if (p
->sched_class
->task_fork
)
2594 p
->sched_class
->task_fork(p
);
2597 cpu
= select_task_rq(p
, SD_BALANCE_FORK
, 0);
2599 set_task_cpu(p
, cpu
);
2601 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
2602 if (likely(sched_info_on()))
2603 memset(&p
->sched_info
, 0, sizeof(p
->sched_info
));
2605 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
2608 #ifdef CONFIG_PREEMPT
2609 /* Want to start with kernel preemption disabled. */
2610 task_thread_info(p
)->preempt_count
= 1;
2612 plist_node_init(&p
->pushable_tasks
, MAX_PRIO
);
2618 * wake_up_new_task - wake up a newly created task for the first time.
2620 * This function will do some initial scheduler statistics housekeeping
2621 * that must be done for every newly created context, then puts the task
2622 * on the runqueue and wakes it.
2624 void wake_up_new_task(struct task_struct
*p
, unsigned long clone_flags
)
2626 unsigned long flags
;
2629 rq
= task_rq_lock(p
, &flags
);
2630 BUG_ON(p
->state
!= TASK_RUNNING
);
2631 update_rq_clock(rq
);
2632 activate_task(rq
, p
, 0);
2633 trace_sched_wakeup_new(rq
, p
, 1);
2634 check_preempt_curr(rq
, p
, WF_FORK
);
2636 if (p
->sched_class
->task_wake_up
)
2637 p
->sched_class
->task_wake_up(rq
, p
);
2639 task_rq_unlock(rq
, &flags
);
2642 #ifdef CONFIG_PREEMPT_NOTIFIERS
2645 * preempt_notifier_register - tell me when current is being preempted & rescheduled
2646 * @notifier: notifier struct to register
2648 void preempt_notifier_register(struct preempt_notifier
*notifier
)
2650 hlist_add_head(¬ifier
->link
, ¤t
->preempt_notifiers
);
2652 EXPORT_SYMBOL_GPL(preempt_notifier_register
);
2655 * preempt_notifier_unregister - no longer interested in preemption notifications
2656 * @notifier: notifier struct to unregister
2658 * This is safe to call from within a preemption notifier.
2660 void preempt_notifier_unregister(struct preempt_notifier
*notifier
)
2662 hlist_del(¬ifier
->link
);
2664 EXPORT_SYMBOL_GPL(preempt_notifier_unregister
);
2666 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2668 struct preempt_notifier
*notifier
;
2669 struct hlist_node
*node
;
2671 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
2672 notifier
->ops
->sched_in(notifier
, raw_smp_processor_id());
2676 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2677 struct task_struct
*next
)
2679 struct preempt_notifier
*notifier
;
2680 struct hlist_node
*node
;
2682 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
2683 notifier
->ops
->sched_out(notifier
, next
);
2686 #else /* !CONFIG_PREEMPT_NOTIFIERS */
2688 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2693 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2694 struct task_struct
*next
)
2698 #endif /* CONFIG_PREEMPT_NOTIFIERS */
2701 * prepare_task_switch - prepare to switch tasks
2702 * @rq: the runqueue preparing to switch
2703 * @prev: the current task that is being switched out
2704 * @next: the task we are going to switch to.
2706 * This is called with the rq lock held and interrupts off. It must
2707 * be paired with a subsequent finish_task_switch after the context
2710 * prepare_task_switch sets up locking and calls architecture specific
2714 prepare_task_switch(struct rq
*rq
, struct task_struct
*prev
,
2715 struct task_struct
*next
)
2717 fire_sched_out_preempt_notifiers(prev
, next
);
2718 prepare_lock_switch(rq
, next
);
2719 prepare_arch_switch(next
);
2723 * finish_task_switch - clean up after a task-switch
2724 * @rq: runqueue associated with task-switch
2725 * @prev: the thread we just switched away from.
2727 * finish_task_switch must be called after the context switch, paired
2728 * with a prepare_task_switch call before the context switch.
2729 * finish_task_switch will reconcile locking set up by prepare_task_switch,
2730 * and do any other architecture-specific cleanup actions.
2732 * Note that we may have delayed dropping an mm in context_switch(). If
2733 * so, we finish that here outside of the runqueue lock. (Doing it
2734 * with the lock held can cause deadlocks; see schedule() for
2737 static void finish_task_switch(struct rq
*rq
, struct task_struct
*prev
)
2738 __releases(rq
->lock
)
2740 struct mm_struct
*mm
= rq
->prev_mm
;
2746 * A task struct has one reference for the use as "current".
2747 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
2748 * schedule one last time. The schedule call will never return, and
2749 * the scheduled task must drop that reference.
2750 * The test for TASK_DEAD must occur while the runqueue locks are
2751 * still held, otherwise prev could be scheduled on another cpu, die
2752 * there before we look at prev->state, and then the reference would
2754 * Manfred Spraul <manfred@colorfullife.com>
2756 prev_state
= prev
->state
;
2757 finish_arch_switch(prev
);
2758 perf_event_task_sched_in(current
, cpu_of(rq
));
2759 finish_lock_switch(rq
, prev
);
2761 fire_sched_in_preempt_notifiers(current
);
2764 if (unlikely(prev_state
== TASK_DEAD
)) {
2766 * Remove function-return probe instances associated with this
2767 * task and put them back on the free list.
2769 kprobe_flush_task(prev
);
2770 put_task_struct(prev
);
2776 /* assumes rq->lock is held */
2777 static inline void pre_schedule(struct rq
*rq
, struct task_struct
*prev
)
2779 if (prev
->sched_class
->pre_schedule
)
2780 prev
->sched_class
->pre_schedule(rq
, prev
);
2783 /* rq->lock is NOT held, but preemption is disabled */
2784 static inline void post_schedule(struct rq
*rq
)
2786 if (rq
->post_schedule
) {
2787 unsigned long flags
;
2789 spin_lock_irqsave(&rq
->lock
, flags
);
2790 if (rq
->curr
->sched_class
->post_schedule
)
2791 rq
->curr
->sched_class
->post_schedule(rq
);
2792 spin_unlock_irqrestore(&rq
->lock
, flags
);
2794 rq
->post_schedule
= 0;
2800 static inline void pre_schedule(struct rq
*rq
, struct task_struct
*p
)
2804 static inline void post_schedule(struct rq
*rq
)
2811 * schedule_tail - first thing a freshly forked thread must call.
2812 * @prev: the thread we just switched away from.
2814 asmlinkage
void schedule_tail(struct task_struct
*prev
)
2815 __releases(rq
->lock
)
2817 struct rq
*rq
= this_rq();
2819 finish_task_switch(rq
, prev
);
2822 * FIXME: do we need to worry about rq being invalidated by the
2827 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
2828 /* In this case, finish_task_switch does not reenable preemption */
2831 if (current
->set_child_tid
)
2832 put_user(task_pid_vnr(current
), current
->set_child_tid
);
2836 * context_switch - switch to the new MM and the new
2837 * thread's register state.
2840 context_switch(struct rq
*rq
, struct task_struct
*prev
,
2841 struct task_struct
*next
)
2843 struct mm_struct
*mm
, *oldmm
;
2845 prepare_task_switch(rq
, prev
, next
);
2846 trace_sched_switch(rq
, prev
, next
);
2848 oldmm
= prev
->active_mm
;
2850 * For paravirt, this is coupled with an exit in switch_to to
2851 * combine the page table reload and the switch backend into
2854 arch_start_context_switch(prev
);
2857 next
->active_mm
= oldmm
;
2858 atomic_inc(&oldmm
->mm_count
);
2859 enter_lazy_tlb(oldmm
, next
);
2861 switch_mm(oldmm
, mm
, next
);
2863 if (likely(!prev
->mm
)) {
2864 prev
->active_mm
= NULL
;
2865 rq
->prev_mm
= oldmm
;
2868 * Since the runqueue lock will be released by the next
2869 * task (which is an invalid locking op but in the case
2870 * of the scheduler it's an obvious special-case), so we
2871 * do an early lockdep release here:
2873 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
2874 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
2877 /* Here we just switch the register state and the stack. */
2878 switch_to(prev
, next
, prev
);
2882 * this_rq must be evaluated again because prev may have moved
2883 * CPUs since it called schedule(), thus the 'rq' on its stack
2884 * frame will be invalid.
2886 finish_task_switch(this_rq(), prev
);
2890 * nr_running, nr_uninterruptible and nr_context_switches:
2892 * externally visible scheduler statistics: current number of runnable
2893 * threads, current number of uninterruptible-sleeping threads, total
2894 * number of context switches performed since bootup.
2896 unsigned long nr_running(void)
2898 unsigned long i
, sum
= 0;
2900 for_each_online_cpu(i
)
2901 sum
+= cpu_rq(i
)->nr_running
;
2906 unsigned long nr_uninterruptible(void)
2908 unsigned long i
, sum
= 0;
2910 for_each_possible_cpu(i
)
2911 sum
+= cpu_rq(i
)->nr_uninterruptible
;
2914 * Since we read the counters lockless, it might be slightly
2915 * inaccurate. Do not allow it to go below zero though:
2917 if (unlikely((long)sum
< 0))
2923 unsigned long long nr_context_switches(void)
2926 unsigned long long sum
= 0;
2928 for_each_possible_cpu(i
)
2929 sum
+= cpu_rq(i
)->nr_switches
;
2934 unsigned long nr_iowait(void)
2936 unsigned long i
, sum
= 0;
2938 for_each_possible_cpu(i
)
2939 sum
+= atomic_read(&cpu_rq(i
)->nr_iowait
);
2944 unsigned long nr_iowait_cpu(void)
2946 struct rq
*this = this_rq();
2947 return atomic_read(&this->nr_iowait
);
2950 unsigned long this_cpu_load(void)
2952 struct rq
*this = this_rq();
2953 return this->cpu_load
[0];
2957 /* Variables and functions for calc_load */
2958 static atomic_long_t calc_load_tasks
;
2959 static unsigned long calc_load_update
;
2960 unsigned long avenrun
[3];
2961 EXPORT_SYMBOL(avenrun
);
2964 * get_avenrun - get the load average array
2965 * @loads: pointer to dest load array
2966 * @offset: offset to add
2967 * @shift: shift count to shift the result left
2969 * These values are estimates at best, so no need for locking.
2971 void get_avenrun(unsigned long *loads
, unsigned long offset
, int shift
)
2973 loads
[0] = (avenrun
[0] + offset
) << shift
;
2974 loads
[1] = (avenrun
[1] + offset
) << shift
;
2975 loads
[2] = (avenrun
[2] + offset
) << shift
;
2978 static unsigned long
2979 calc_load(unsigned long load
, unsigned long exp
, unsigned long active
)
2982 load
+= active
* (FIXED_1
- exp
);
2983 return load
>> FSHIFT
;
2987 * calc_load - update the avenrun load estimates 10 ticks after the
2988 * CPUs have updated calc_load_tasks.
2990 void calc_global_load(void)
2992 unsigned long upd
= calc_load_update
+ 10;
2995 if (time_before(jiffies
, upd
))
2998 active
= atomic_long_read(&calc_load_tasks
);
2999 active
= active
> 0 ? active
* FIXED_1
: 0;
3001 avenrun
[0] = calc_load(avenrun
[0], EXP_1
, active
);
3002 avenrun
[1] = calc_load(avenrun
[1], EXP_5
, active
);
3003 avenrun
[2] = calc_load(avenrun
[2], EXP_15
, active
);
3005 calc_load_update
+= LOAD_FREQ
;
3009 * Either called from update_cpu_load() or from a cpu going idle
3011 static void calc_load_account_active(struct rq
*this_rq
)
3013 long nr_active
, delta
;
3015 nr_active
= this_rq
->nr_running
;
3016 nr_active
+= (long) this_rq
->nr_uninterruptible
;
3018 if (nr_active
!= this_rq
->calc_load_active
) {
3019 delta
= nr_active
- this_rq
->calc_load_active
;
3020 this_rq
->calc_load_active
= nr_active
;
3021 atomic_long_add(delta
, &calc_load_tasks
);
3026 * Update rq->cpu_load[] statistics. This function is usually called every
3027 * scheduler tick (TICK_NSEC).
3029 static void update_cpu_load(struct rq
*this_rq
)
3031 unsigned long this_load
= this_rq
->load
.weight
;
3034 this_rq
->nr_load_updates
++;
3036 /* Update our load: */
3037 for (i
= 0, scale
= 1; i
< CPU_LOAD_IDX_MAX
; i
++, scale
+= scale
) {
3038 unsigned long old_load
, new_load
;
3040 /* scale is effectively 1 << i now, and >> i divides by scale */
3042 old_load
= this_rq
->cpu_load
[i
];
3043 new_load
= this_load
;
3045 * Round up the averaging division if load is increasing. This
3046 * prevents us from getting stuck on 9 if the load is 10, for
3049 if (new_load
> old_load
)
3050 new_load
+= scale
-1;
3051 this_rq
->cpu_load
[i
] = (old_load
*(scale
-1) + new_load
) >> i
;
3054 if (time_after_eq(jiffies
, this_rq
->calc_load_update
)) {
3055 this_rq
->calc_load_update
+= LOAD_FREQ
;
3056 calc_load_account_active(this_rq
);
3063 * double_rq_lock - safely lock two runqueues
3065 * Note this does not disable interrupts like task_rq_lock,
3066 * you need to do so manually before calling.
3068 static void double_rq_lock(struct rq
*rq1
, struct rq
*rq2
)
3069 __acquires(rq1
->lock
)
3070 __acquires(rq2
->lock
)
3072 BUG_ON(!irqs_disabled());
3074 spin_lock(&rq1
->lock
);
3075 __acquire(rq2
->lock
); /* Fake it out ;) */
3078 spin_lock(&rq1
->lock
);
3079 spin_lock_nested(&rq2
->lock
, SINGLE_DEPTH_NESTING
);
3081 spin_lock(&rq2
->lock
);
3082 spin_lock_nested(&rq1
->lock
, SINGLE_DEPTH_NESTING
);
3085 update_rq_clock(rq1
);
3086 update_rq_clock(rq2
);
3090 * double_rq_unlock - safely unlock two runqueues
3092 * Note this does not restore interrupts like task_rq_unlock,
3093 * you need to do so manually after calling.
3095 static void double_rq_unlock(struct rq
*rq1
, struct rq
*rq2
)
3096 __releases(rq1
->lock
)
3097 __releases(rq2
->lock
)
3099 spin_unlock(&rq1
->lock
);
3101 spin_unlock(&rq2
->lock
);
3103 __release(rq2
->lock
);
3107 * If dest_cpu is allowed for this process, migrate the task to it.
3108 * This is accomplished by forcing the cpu_allowed mask to only
3109 * allow dest_cpu, which will force the cpu onto dest_cpu. Then
3110 * the cpu_allowed mask is restored.
3112 static void sched_migrate_task(struct task_struct
*p
, int dest_cpu
)
3114 struct migration_req req
;
3115 unsigned long flags
;
3118 rq
= task_rq_lock(p
, &flags
);
3119 if (!cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
)
3120 || unlikely(!cpu_active(dest_cpu
)))
3123 /* force the process onto the specified CPU */
3124 if (migrate_task(p
, dest_cpu
, &req
)) {
3125 /* Need to wait for migration thread (might exit: take ref). */
3126 struct task_struct
*mt
= rq
->migration_thread
;
3128 get_task_struct(mt
);
3129 task_rq_unlock(rq
, &flags
);
3130 wake_up_process(mt
);
3131 put_task_struct(mt
);
3132 wait_for_completion(&req
.done
);
3137 task_rq_unlock(rq
, &flags
);
3141 * sched_exec - execve() is a valuable balancing opportunity, because at
3142 * this point the task has the smallest effective memory and cache footprint.
3144 void sched_exec(void)
3146 int new_cpu
, this_cpu
= get_cpu();
3147 new_cpu
= select_task_rq(current
, SD_BALANCE_EXEC
, 0);
3149 if (new_cpu
!= this_cpu
)
3150 sched_migrate_task(current
, new_cpu
);
3154 * pull_task - move a task from a remote runqueue to the local runqueue.
3155 * Both runqueues must be locked.
3157 static void pull_task(struct rq
*src_rq
, struct task_struct
*p
,
3158 struct rq
*this_rq
, int this_cpu
)
3160 deactivate_task(src_rq
, p
, 0);
3161 set_task_cpu(p
, this_cpu
);
3162 activate_task(this_rq
, p
, 0);
3163 check_preempt_curr(this_rq
, p
, 0);
3167 * can_migrate_task - may task p from runqueue rq be migrated to this_cpu?
3170 int can_migrate_task(struct task_struct
*p
, struct rq
*rq
, int this_cpu
,
3171 struct sched_domain
*sd
, enum cpu_idle_type idle
,
3174 int tsk_cache_hot
= 0;
3176 * We do not migrate tasks that are:
3177 * 1) running (obviously), or
3178 * 2) cannot be migrated to this CPU due to cpus_allowed, or
3179 * 3) are cache-hot on their current CPU.
3181 if (!cpumask_test_cpu(this_cpu
, &p
->cpus_allowed
)) {
3182 schedstat_inc(p
, se
.nr_failed_migrations_affine
);
3187 if (task_running(rq
, p
)) {
3188 schedstat_inc(p
, se
.nr_failed_migrations_running
);
3193 * Aggressive migration if:
3194 * 1) task is cache cold, or
3195 * 2) too many balance attempts have failed.
3198 tsk_cache_hot
= task_hot(p
, rq
->clock
, sd
);
3199 if (!tsk_cache_hot
||
3200 sd
->nr_balance_failed
> sd
->cache_nice_tries
) {
3201 #ifdef CONFIG_SCHEDSTATS
3202 if (tsk_cache_hot
) {
3203 schedstat_inc(sd
, lb_hot_gained
[idle
]);
3204 schedstat_inc(p
, se
.nr_forced_migrations
);
3210 if (tsk_cache_hot
) {
3211 schedstat_inc(p
, se
.nr_failed_migrations_hot
);
3217 static unsigned long
3218 balance_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
3219 unsigned long max_load_move
, struct sched_domain
*sd
,
3220 enum cpu_idle_type idle
, int *all_pinned
,
3221 int *this_best_prio
, struct rq_iterator
*iterator
)
3223 int loops
= 0, pulled
= 0, pinned
= 0;
3224 struct task_struct
*p
;
3225 long rem_load_move
= max_load_move
;
3227 if (max_load_move
== 0)
3233 * Start the load-balancing iterator:
3235 p
= iterator
->start(iterator
->arg
);
3237 if (!p
|| loops
++ > sysctl_sched_nr_migrate
)
3240 if ((p
->se
.load
.weight
>> 1) > rem_load_move
||
3241 !can_migrate_task(p
, busiest
, this_cpu
, sd
, idle
, &pinned
)) {
3242 p
= iterator
->next(iterator
->arg
);
3246 pull_task(busiest
, p
, this_rq
, this_cpu
);
3248 rem_load_move
-= p
->se
.load
.weight
;
3250 #ifdef CONFIG_PREEMPT
3252 * NEWIDLE balancing is a source of latency, so preemptible kernels
3253 * will stop after the first task is pulled to minimize the critical
3256 if (idle
== CPU_NEWLY_IDLE
)
3261 * We only want to steal up to the prescribed amount of weighted load.
3263 if (rem_load_move
> 0) {
3264 if (p
->prio
< *this_best_prio
)
3265 *this_best_prio
= p
->prio
;
3266 p
= iterator
->next(iterator
->arg
);
3271 * Right now, this is one of only two places pull_task() is called,
3272 * so we can safely collect pull_task() stats here rather than
3273 * inside pull_task().
3275 schedstat_add(sd
, lb_gained
[idle
], pulled
);
3278 *all_pinned
= pinned
;
3280 return max_load_move
- rem_load_move
;
3284 * move_tasks tries to move up to max_load_move weighted load from busiest to
3285 * this_rq, as part of a balancing operation within domain "sd".
3286 * Returns 1 if successful and 0 otherwise.
3288 * Called with both runqueues locked.
3290 static int move_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
3291 unsigned long max_load_move
,
3292 struct sched_domain
*sd
, enum cpu_idle_type idle
,
3295 const struct sched_class
*class = sched_class_highest
;
3296 unsigned long total_load_moved
= 0;
3297 int this_best_prio
= this_rq
->curr
->prio
;
3301 class->load_balance(this_rq
, this_cpu
, busiest
,
3302 max_load_move
- total_load_moved
,
3303 sd
, idle
, all_pinned
, &this_best_prio
);
3304 class = class->next
;
3306 #ifdef CONFIG_PREEMPT
3308 * NEWIDLE balancing is a source of latency, so preemptible
3309 * kernels will stop after the first task is pulled to minimize
3310 * the critical section.
3312 if (idle
== CPU_NEWLY_IDLE
&& this_rq
->nr_running
)
3315 } while (class && max_load_move
> total_load_moved
);
3317 return total_load_moved
> 0;
3321 iter_move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
3322 struct sched_domain
*sd
, enum cpu_idle_type idle
,
3323 struct rq_iterator
*iterator
)
3325 struct task_struct
*p
= iterator
->start(iterator
->arg
);
3329 if (can_migrate_task(p
, busiest
, this_cpu
, sd
, idle
, &pinned
)) {
3330 pull_task(busiest
, p
, this_rq
, this_cpu
);
3332 * Right now, this is only the second place pull_task()
3333 * is called, so we can safely collect pull_task()
3334 * stats here rather than inside pull_task().
3336 schedstat_inc(sd
, lb_gained
[idle
]);
3340 p
= iterator
->next(iterator
->arg
);
3347 * move_one_task tries to move exactly one task from busiest to this_rq, as
3348 * part of active balancing operations within "domain".
3349 * Returns 1 if successful and 0 otherwise.
3351 * Called with both runqueues locked.
3353 static int move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
3354 struct sched_domain
*sd
, enum cpu_idle_type idle
)
3356 const struct sched_class
*class;
3358 for_each_class(class) {
3359 if (class->move_one_task(this_rq
, this_cpu
, busiest
, sd
, idle
))
3365 /********** Helpers for find_busiest_group ************************/
3367 * sd_lb_stats - Structure to store the statistics of a sched_domain
3368 * during load balancing.
3370 struct sd_lb_stats
{
3371 struct sched_group
*busiest
; /* Busiest group in this sd */
3372 struct sched_group
*this; /* Local group in this sd */
3373 unsigned long total_load
; /* Total load of all groups in sd */
3374 unsigned long total_pwr
; /* Total power of all groups in sd */
3375 unsigned long avg_load
; /* Average load across all groups in sd */
3377 /** Statistics of this group */
3378 unsigned long this_load
;
3379 unsigned long this_load_per_task
;
3380 unsigned long this_nr_running
;
3382 /* Statistics of the busiest group */
3383 unsigned long max_load
;
3384 unsigned long busiest_load_per_task
;
3385 unsigned long busiest_nr_running
;
3387 int group_imb
; /* Is there imbalance in this sd */
3388 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3389 int power_savings_balance
; /* Is powersave balance needed for this sd */
3390 struct sched_group
*group_min
; /* Least loaded group in sd */
3391 struct sched_group
*group_leader
; /* Group which relieves group_min */
3392 unsigned long min_load_per_task
; /* load_per_task in group_min */
3393 unsigned long leader_nr_running
; /* Nr running of group_leader */
3394 unsigned long min_nr_running
; /* Nr running of group_min */
3399 * sg_lb_stats - stats of a sched_group required for load_balancing
3401 struct sg_lb_stats
{
3402 unsigned long avg_load
; /*Avg load across the CPUs of the group */
3403 unsigned long group_load
; /* Total load over the CPUs of the group */
3404 unsigned long sum_nr_running
; /* Nr tasks running in the group */
3405 unsigned long sum_weighted_load
; /* Weighted load of group's tasks */
3406 unsigned long group_capacity
;
3407 int group_imb
; /* Is there an imbalance in the group ? */
3411 * group_first_cpu - Returns the first cpu in the cpumask of a sched_group.
3412 * @group: The group whose first cpu is to be returned.
3414 static inline unsigned int group_first_cpu(struct sched_group
*group
)
3416 return cpumask_first(sched_group_cpus(group
));
3420 * get_sd_load_idx - Obtain the load index for a given sched domain.
3421 * @sd: The sched_domain whose load_idx is to be obtained.
3422 * @idle: The Idle status of the CPU for whose sd load_icx is obtained.
3424 static inline int get_sd_load_idx(struct sched_domain
*sd
,
3425 enum cpu_idle_type idle
)
3431 load_idx
= sd
->busy_idx
;
3434 case CPU_NEWLY_IDLE
:
3435 load_idx
= sd
->newidle_idx
;
3438 load_idx
= sd
->idle_idx
;
3446 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3448 * init_sd_power_savings_stats - Initialize power savings statistics for
3449 * the given sched_domain, during load balancing.
3451 * @sd: Sched domain whose power-savings statistics are to be initialized.
3452 * @sds: Variable containing the statistics for sd.
3453 * @idle: Idle status of the CPU at which we're performing load-balancing.
3455 static inline void init_sd_power_savings_stats(struct sched_domain
*sd
,
3456 struct sd_lb_stats
*sds
, enum cpu_idle_type idle
)
3459 * Busy processors will not participate in power savings
3462 if (idle
== CPU_NOT_IDLE
|| !(sd
->flags
& SD_POWERSAVINGS_BALANCE
))
3463 sds
->power_savings_balance
= 0;
3465 sds
->power_savings_balance
= 1;
3466 sds
->min_nr_running
= ULONG_MAX
;
3467 sds
->leader_nr_running
= 0;
3472 * update_sd_power_savings_stats - Update the power saving stats for a
3473 * sched_domain while performing load balancing.
3475 * @group: sched_group belonging to the sched_domain under consideration.
3476 * @sds: Variable containing the statistics of the sched_domain
3477 * @local_group: Does group contain the CPU for which we're performing
3479 * @sgs: Variable containing the statistics of the group.
3481 static inline void update_sd_power_savings_stats(struct sched_group
*group
,
3482 struct sd_lb_stats
*sds
, int local_group
, struct sg_lb_stats
*sgs
)
3485 if (!sds
->power_savings_balance
)
3489 * If the local group is idle or completely loaded
3490 * no need to do power savings balance at this domain
3492 if (local_group
&& (sds
->this_nr_running
>= sgs
->group_capacity
||
3493 !sds
->this_nr_running
))
3494 sds
->power_savings_balance
= 0;
3497 * If a group is already running at full capacity or idle,
3498 * don't include that group in power savings calculations
3500 if (!sds
->power_savings_balance
||
3501 sgs
->sum_nr_running
>= sgs
->group_capacity
||
3502 !sgs
->sum_nr_running
)
3506 * Calculate the group which has the least non-idle load.
3507 * This is the group from where we need to pick up the load
3510 if ((sgs
->sum_nr_running
< sds
->min_nr_running
) ||
3511 (sgs
->sum_nr_running
== sds
->min_nr_running
&&
3512 group_first_cpu(group
) > group_first_cpu(sds
->group_min
))) {
3513 sds
->group_min
= group
;
3514 sds
->min_nr_running
= sgs
->sum_nr_running
;
3515 sds
->min_load_per_task
= sgs
->sum_weighted_load
/
3516 sgs
->sum_nr_running
;
3520 * Calculate the group which is almost near its
3521 * capacity but still has some space to pick up some load
3522 * from other group and save more power
3524 if (sgs
->sum_nr_running
+ 1 > sgs
->group_capacity
)
3527 if (sgs
->sum_nr_running
> sds
->leader_nr_running
||
3528 (sgs
->sum_nr_running
== sds
->leader_nr_running
&&
3529 group_first_cpu(group
) < group_first_cpu(sds
->group_leader
))) {
3530 sds
->group_leader
= group
;
3531 sds
->leader_nr_running
= sgs
->sum_nr_running
;
3536 * check_power_save_busiest_group - see if there is potential for some power-savings balance
3537 * @sds: Variable containing the statistics of the sched_domain
3538 * under consideration.
3539 * @this_cpu: Cpu at which we're currently performing load-balancing.
3540 * @imbalance: Variable to store the imbalance.
3543 * Check if we have potential to perform some power-savings balance.
3544 * If yes, set the busiest group to be the least loaded group in the
3545 * sched_domain, so that it's CPUs can be put to idle.
3547 * Returns 1 if there is potential to perform power-savings balance.
3550 static inline int check_power_save_busiest_group(struct sd_lb_stats
*sds
,
3551 int this_cpu
, unsigned long *imbalance
)
3553 if (!sds
->power_savings_balance
)
3556 if (sds
->this != sds
->group_leader
||
3557 sds
->group_leader
== sds
->group_min
)
3560 *imbalance
= sds
->min_load_per_task
;
3561 sds
->busiest
= sds
->group_min
;
3566 #else /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
3567 static inline void init_sd_power_savings_stats(struct sched_domain
*sd
,
3568 struct sd_lb_stats
*sds
, enum cpu_idle_type idle
)
3573 static inline void update_sd_power_savings_stats(struct sched_group
*group
,
3574 struct sd_lb_stats
*sds
, int local_group
, struct sg_lb_stats
*sgs
)
3579 static inline int check_power_save_busiest_group(struct sd_lb_stats
*sds
,
3580 int this_cpu
, unsigned long *imbalance
)
3584 #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
3587 unsigned long default_scale_freq_power(struct sched_domain
*sd
, int cpu
)
3589 return SCHED_LOAD_SCALE
;
3592 unsigned long __weak
arch_scale_freq_power(struct sched_domain
*sd
, int cpu
)
3594 return default_scale_freq_power(sd
, cpu
);
3597 unsigned long default_scale_smt_power(struct sched_domain
*sd
, int cpu
)
3599 unsigned long weight
= cpumask_weight(sched_domain_span(sd
));
3600 unsigned long smt_gain
= sd
->smt_gain
;
3607 unsigned long __weak
arch_scale_smt_power(struct sched_domain
*sd
, int cpu
)
3609 return default_scale_smt_power(sd
, cpu
);
3612 unsigned long scale_rt_power(int cpu
)
3614 struct rq
*rq
= cpu_rq(cpu
);
3615 u64 total
, available
;
3617 sched_avg_update(rq
);
3619 total
= sched_avg_period() + (rq
->clock
- rq
->age_stamp
);
3620 available
= total
- rq
->rt_avg
;
3622 if (unlikely((s64
)total
< SCHED_LOAD_SCALE
))
3623 total
= SCHED_LOAD_SCALE
;
3625 total
>>= SCHED_LOAD_SHIFT
;
3627 return div_u64(available
, total
);
3630 static void update_cpu_power(struct sched_domain
*sd
, int cpu
)
3632 unsigned long weight
= cpumask_weight(sched_domain_span(sd
));
3633 unsigned long power
= SCHED_LOAD_SCALE
;
3634 struct sched_group
*sdg
= sd
->groups
;
3636 if (sched_feat(ARCH_POWER
))
3637 power
*= arch_scale_freq_power(sd
, cpu
);
3639 power
*= default_scale_freq_power(sd
, cpu
);
3641 power
>>= SCHED_LOAD_SHIFT
;
3643 if ((sd
->flags
& SD_SHARE_CPUPOWER
) && weight
> 1) {
3644 if (sched_feat(ARCH_POWER
))
3645 power
*= arch_scale_smt_power(sd
, cpu
);
3647 power
*= default_scale_smt_power(sd
, cpu
);
3649 power
>>= SCHED_LOAD_SHIFT
;
3652 power
*= scale_rt_power(cpu
);
3653 power
>>= SCHED_LOAD_SHIFT
;
3658 sdg
->cpu_power
= power
;
3661 static void update_group_power(struct sched_domain
*sd
, int cpu
)
3663 struct sched_domain
*child
= sd
->child
;
3664 struct sched_group
*group
, *sdg
= sd
->groups
;
3665 unsigned long power
;
3668 update_cpu_power(sd
, cpu
);
3674 group
= child
->groups
;
3676 power
+= group
->cpu_power
;
3677 group
= group
->next
;
3678 } while (group
!= child
->groups
);
3680 sdg
->cpu_power
= power
;
3684 * update_sg_lb_stats - Update sched_group's statistics for load balancing.
3685 * @sd: The sched_domain whose statistics are to be updated.
3686 * @group: sched_group whose statistics are to be updated.
3687 * @this_cpu: Cpu for which load balance is currently performed.
3688 * @idle: Idle status of this_cpu
3689 * @load_idx: Load index of sched_domain of this_cpu for load calc.
3690 * @sd_idle: Idle status of the sched_domain containing group.
3691 * @local_group: Does group contain this_cpu.
3692 * @cpus: Set of cpus considered for load balancing.
3693 * @balance: Should we balance.
3694 * @sgs: variable to hold the statistics for this group.
3696 static inline void update_sg_lb_stats(struct sched_domain
*sd
,
3697 struct sched_group
*group
, int this_cpu
,
3698 enum cpu_idle_type idle
, int load_idx
, int *sd_idle
,
3699 int local_group
, const struct cpumask
*cpus
,
3700 int *balance
, struct sg_lb_stats
*sgs
)
3702 unsigned long load
, max_cpu_load
, min_cpu_load
;
3704 unsigned int balance_cpu
= -1, first_idle_cpu
= 0;
3705 unsigned long sum_avg_load_per_task
;
3706 unsigned long avg_load_per_task
;
3709 balance_cpu
= group_first_cpu(group
);
3710 if (balance_cpu
== this_cpu
)
3711 update_group_power(sd
, this_cpu
);
3714 /* Tally up the load of all CPUs in the group */
3715 sum_avg_load_per_task
= avg_load_per_task
= 0;
3717 min_cpu_load
= ~0UL;
3719 for_each_cpu_and(i
, sched_group_cpus(group
), cpus
) {
3720 struct rq
*rq
= cpu_rq(i
);
3722 if (*sd_idle
&& rq
->nr_running
)
3725 /* Bias balancing toward cpus of our domain */
3727 if (idle_cpu(i
) && !first_idle_cpu
) {
3732 load
= target_load(i
, load_idx
);
3734 load
= source_load(i
, load_idx
);
3735 if (load
> max_cpu_load
)
3736 max_cpu_load
= load
;
3737 if (min_cpu_load
> load
)
3738 min_cpu_load
= load
;
3741 sgs
->group_load
+= load
;
3742 sgs
->sum_nr_running
+= rq
->nr_running
;
3743 sgs
->sum_weighted_load
+= weighted_cpuload(i
);
3745 sum_avg_load_per_task
+= cpu_avg_load_per_task(i
);
3749 * First idle cpu or the first cpu(busiest) in this sched group
3750 * is eligible for doing load balancing at this and above
3751 * domains. In the newly idle case, we will allow all the cpu's
3752 * to do the newly idle load balance.
3754 if (idle
!= CPU_NEWLY_IDLE
&& local_group
&&
3755 balance_cpu
!= this_cpu
&& balance
) {
3760 /* Adjust by relative CPU power of the group */
3761 sgs
->avg_load
= (sgs
->group_load
* SCHED_LOAD_SCALE
) / group
->cpu_power
;
3765 * Consider the group unbalanced when the imbalance is larger
3766 * than the average weight of two tasks.
3768 * APZ: with cgroup the avg task weight can vary wildly and
3769 * might not be a suitable number - should we keep a
3770 * normalized nr_running number somewhere that negates
3773 avg_load_per_task
= (sum_avg_load_per_task
* SCHED_LOAD_SCALE
) /
3776 if ((max_cpu_load
- min_cpu_load
) > 2*avg_load_per_task
)
3779 sgs
->group_capacity
=
3780 DIV_ROUND_CLOSEST(group
->cpu_power
, SCHED_LOAD_SCALE
);
3784 * update_sd_lb_stats - Update sched_group's statistics for load balancing.
3785 * @sd: sched_domain whose statistics are to be updated.
3786 * @this_cpu: Cpu for which load balance is currently performed.
3787 * @idle: Idle status of this_cpu
3788 * @sd_idle: Idle status of the sched_domain containing group.
3789 * @cpus: Set of cpus considered for load balancing.
3790 * @balance: Should we balance.
3791 * @sds: variable to hold the statistics for this sched_domain.
3793 static inline void update_sd_lb_stats(struct sched_domain
*sd
, int this_cpu
,
3794 enum cpu_idle_type idle
, int *sd_idle
,
3795 const struct cpumask
*cpus
, int *balance
,
3796 struct sd_lb_stats
*sds
)
3798 struct sched_domain
*child
= sd
->child
;
3799 struct sched_group
*group
= sd
->groups
;
3800 struct sg_lb_stats sgs
;
3801 int load_idx
, prefer_sibling
= 0;
3803 if (child
&& child
->flags
& SD_PREFER_SIBLING
)
3806 init_sd_power_savings_stats(sd
, sds
, idle
);
3807 load_idx
= get_sd_load_idx(sd
, idle
);
3812 local_group
= cpumask_test_cpu(this_cpu
,
3813 sched_group_cpus(group
));
3814 memset(&sgs
, 0, sizeof(sgs
));
3815 update_sg_lb_stats(sd
, group
, this_cpu
, idle
, load_idx
, sd_idle
,
3816 local_group
, cpus
, balance
, &sgs
);
3818 if (local_group
&& balance
&& !(*balance
))
3821 sds
->total_load
+= sgs
.group_load
;
3822 sds
->total_pwr
+= group
->cpu_power
;
3825 * In case the child domain prefers tasks go to siblings
3826 * first, lower the group capacity to one so that we'll try
3827 * and move all the excess tasks away.
3830 sgs
.group_capacity
= min(sgs
.group_capacity
, 1UL);
3833 sds
->this_load
= sgs
.avg_load
;
3835 sds
->this_nr_running
= sgs
.sum_nr_running
;
3836 sds
->this_load_per_task
= sgs
.sum_weighted_load
;
3837 } else if (sgs
.avg_load
> sds
->max_load
&&
3838 (sgs
.sum_nr_running
> sgs
.group_capacity
||
3840 sds
->max_load
= sgs
.avg_load
;
3841 sds
->busiest
= group
;
3842 sds
->busiest_nr_running
= sgs
.sum_nr_running
;
3843 sds
->busiest_load_per_task
= sgs
.sum_weighted_load
;
3844 sds
->group_imb
= sgs
.group_imb
;
3847 update_sd_power_savings_stats(group
, sds
, local_group
, &sgs
);
3848 group
= group
->next
;
3849 } while (group
!= sd
->groups
);
3853 * fix_small_imbalance - Calculate the minor imbalance that exists
3854 * amongst the groups of a sched_domain, during
3856 * @sds: Statistics of the sched_domain whose imbalance is to be calculated.
3857 * @this_cpu: The cpu at whose sched_domain we're performing load-balance.
3858 * @imbalance: Variable to store the imbalance.
3860 static inline void fix_small_imbalance(struct sd_lb_stats
*sds
,
3861 int this_cpu
, unsigned long *imbalance
)
3863 unsigned long tmp
, pwr_now
= 0, pwr_move
= 0;
3864 unsigned int imbn
= 2;
3866 if (sds
->this_nr_running
) {
3867 sds
->this_load_per_task
/= sds
->this_nr_running
;
3868 if (sds
->busiest_load_per_task
>
3869 sds
->this_load_per_task
)
3872 sds
->this_load_per_task
=
3873 cpu_avg_load_per_task(this_cpu
);
3875 if (sds
->max_load
- sds
->this_load
+ sds
->busiest_load_per_task
>=
3876 sds
->busiest_load_per_task
* imbn
) {
3877 *imbalance
= sds
->busiest_load_per_task
;
3882 * OK, we don't have enough imbalance to justify moving tasks,
3883 * however we may be able to increase total CPU power used by
3887 pwr_now
+= sds
->busiest
->cpu_power
*
3888 min(sds
->busiest_load_per_task
, sds
->max_load
);
3889 pwr_now
+= sds
->this->cpu_power
*
3890 min(sds
->this_load_per_task
, sds
->this_load
);
3891 pwr_now
/= SCHED_LOAD_SCALE
;
3893 /* Amount of load we'd subtract */
3894 tmp
= (sds
->busiest_load_per_task
* SCHED_LOAD_SCALE
) /
3895 sds
->busiest
->cpu_power
;
3896 if (sds
->max_load
> tmp
)
3897 pwr_move
+= sds
->busiest
->cpu_power
*
3898 min(sds
->busiest_load_per_task
, sds
->max_load
- tmp
);
3900 /* Amount of load we'd add */
3901 if (sds
->max_load
* sds
->busiest
->cpu_power
<
3902 sds
->busiest_load_per_task
* SCHED_LOAD_SCALE
)
3903 tmp
= (sds
->max_load
* sds
->busiest
->cpu_power
) /
3904 sds
->this->cpu_power
;
3906 tmp
= (sds
->busiest_load_per_task
* SCHED_LOAD_SCALE
) /
3907 sds
->this->cpu_power
;
3908 pwr_move
+= sds
->this->cpu_power
*
3909 min(sds
->this_load_per_task
, sds
->this_load
+ tmp
);
3910 pwr_move
/= SCHED_LOAD_SCALE
;
3912 /* Move if we gain throughput */
3913 if (pwr_move
> pwr_now
)
3914 *imbalance
= sds
->busiest_load_per_task
;
3918 * calculate_imbalance - Calculate the amount of imbalance present within the
3919 * groups of a given sched_domain during load balance.
3920 * @sds: statistics of the sched_domain whose imbalance is to be calculated.
3921 * @this_cpu: Cpu for which currently load balance is being performed.
3922 * @imbalance: The variable to store the imbalance.
3924 static inline void calculate_imbalance(struct sd_lb_stats
*sds
, int this_cpu
,
3925 unsigned long *imbalance
)
3927 unsigned long max_pull
;
3929 * In the presence of smp nice balancing, certain scenarios can have
3930 * max load less than avg load(as we skip the groups at or below
3931 * its cpu_power, while calculating max_load..)
3933 if (sds
->max_load
< sds
->avg_load
) {
3935 return fix_small_imbalance(sds
, this_cpu
, imbalance
);
3938 /* Don't want to pull so many tasks that a group would go idle */
3939 max_pull
= min(sds
->max_load
- sds
->avg_load
,
3940 sds
->max_load
- sds
->busiest_load_per_task
);
3942 /* How much load to actually move to equalise the imbalance */
3943 *imbalance
= min(max_pull
* sds
->busiest
->cpu_power
,
3944 (sds
->avg_load
- sds
->this_load
) * sds
->this->cpu_power
)
3948 * if *imbalance is less than the average load per runnable task
3949 * there is no gaurantee that any tasks will be moved so we'll have
3950 * a think about bumping its value to force at least one task to be
3953 if (*imbalance
< sds
->busiest_load_per_task
)
3954 return fix_small_imbalance(sds
, this_cpu
, imbalance
);
3957 /******* find_busiest_group() helpers end here *********************/
3960 * find_busiest_group - Returns the busiest group within the sched_domain
3961 * if there is an imbalance. If there isn't an imbalance, and
3962 * the user has opted for power-savings, it returns a group whose
3963 * CPUs can be put to idle by rebalancing those tasks elsewhere, if
3964 * such a group exists.
3966 * Also calculates the amount of weighted load which should be moved
3967 * to restore balance.
3969 * @sd: The sched_domain whose busiest group is to be returned.
3970 * @this_cpu: The cpu for which load balancing is currently being performed.
3971 * @imbalance: Variable which stores amount of weighted load which should
3972 * be moved to restore balance/put a group to idle.
3973 * @idle: The idle status of this_cpu.
3974 * @sd_idle: The idleness of sd
3975 * @cpus: The set of CPUs under consideration for load-balancing.
3976 * @balance: Pointer to a variable indicating if this_cpu
3977 * is the appropriate cpu to perform load balancing at this_level.
3979 * Returns: - the busiest group if imbalance exists.
3980 * - If no imbalance and user has opted for power-savings balance,
3981 * return the least loaded group whose CPUs can be
3982 * put to idle by rebalancing its tasks onto our group.
3984 static struct sched_group
*
3985 find_busiest_group(struct sched_domain
*sd
, int this_cpu
,
3986 unsigned long *imbalance
, enum cpu_idle_type idle
,
3987 int *sd_idle
, const struct cpumask
*cpus
, int *balance
)
3989 struct sd_lb_stats sds
;
3991 memset(&sds
, 0, sizeof(sds
));
3994 * Compute the various statistics relavent for load balancing at
3997 update_sd_lb_stats(sd
, this_cpu
, idle
, sd_idle
, cpus
,
4000 /* Cases where imbalance does not exist from POV of this_cpu */
4001 /* 1) this_cpu is not the appropriate cpu to perform load balancing
4003 * 2) There is no busy sibling group to pull from.
4004 * 3) This group is the busiest group.
4005 * 4) This group is more busy than the avg busieness at this
4007 * 5) The imbalance is within the specified limit.
4008 * 6) Any rebalance would lead to ping-pong
4010 if (balance
&& !(*balance
))
4013 if (!sds
.busiest
|| sds
.busiest_nr_running
== 0)
4016 if (sds
.this_load
>= sds
.max_load
)
4019 sds
.avg_load
= (SCHED_LOAD_SCALE
* sds
.total_load
) / sds
.total_pwr
;
4021 if (sds
.this_load
>= sds
.avg_load
)
4024 if (100 * sds
.max_load
<= sd
->imbalance_pct
* sds
.this_load
)
4027 sds
.busiest_load_per_task
/= sds
.busiest_nr_running
;
4029 sds
.busiest_load_per_task
=
4030 min(sds
.busiest_load_per_task
, sds
.avg_load
);
4033 * We're trying to get all the cpus to the average_load, so we don't
4034 * want to push ourselves above the average load, nor do we wish to
4035 * reduce the max loaded cpu below the average load, as either of these
4036 * actions would just result in more rebalancing later, and ping-pong
4037 * tasks around. Thus we look for the minimum possible imbalance.
4038 * Negative imbalances (*we* are more loaded than anyone else) will
4039 * be counted as no imbalance for these purposes -- we can't fix that
4040 * by pulling tasks to us. Be careful of negative numbers as they'll
4041 * appear as very large values with unsigned longs.
4043 if (sds
.max_load
<= sds
.busiest_load_per_task
)
4046 /* Looks like there is an imbalance. Compute it */
4047 calculate_imbalance(&sds
, this_cpu
, imbalance
);
4052 * There is no obvious imbalance. But check if we can do some balancing
4055 if (check_power_save_busiest_group(&sds
, this_cpu
, imbalance
))
4063 * find_busiest_queue - find the busiest runqueue among the cpus in group.
4066 find_busiest_queue(struct sched_group
*group
, enum cpu_idle_type idle
,
4067 unsigned long imbalance
, const struct cpumask
*cpus
)
4069 struct rq
*busiest
= NULL
, *rq
;
4070 unsigned long max_load
= 0;
4073 for_each_cpu(i
, sched_group_cpus(group
)) {
4074 unsigned long power
= power_of(i
);
4075 unsigned long capacity
= DIV_ROUND_CLOSEST(power
, SCHED_LOAD_SCALE
);
4078 if (!cpumask_test_cpu(i
, cpus
))
4082 wl
= weighted_cpuload(i
) * SCHED_LOAD_SCALE
;
4085 if (capacity
&& rq
->nr_running
== 1 && wl
> imbalance
)
4088 if (wl
> max_load
) {
4098 * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but
4099 * so long as it is large enough.
4101 #define MAX_PINNED_INTERVAL 512
4103 /* Working cpumask for load_balance and load_balance_newidle. */
4104 static DEFINE_PER_CPU(cpumask_var_t
, load_balance_tmpmask
);
4107 * Check this_cpu to ensure it is balanced within domain. Attempt to move
4108 * tasks if there is an imbalance.
4110 static int load_balance(int this_cpu
, struct rq
*this_rq
,
4111 struct sched_domain
*sd
, enum cpu_idle_type idle
,
4114 int ld_moved
, all_pinned
= 0, active_balance
= 0, sd_idle
= 0;
4115 struct sched_group
*group
;
4116 unsigned long imbalance
;
4118 unsigned long flags
;
4119 struct cpumask
*cpus
= __get_cpu_var(load_balance_tmpmask
);
4121 cpumask_copy(cpus
, cpu_active_mask
);
4124 * When power savings policy is enabled for the parent domain, idle
4125 * sibling can pick up load irrespective of busy siblings. In this case,
4126 * let the state of idle sibling percolate up as CPU_IDLE, instead of
4127 * portraying it as CPU_NOT_IDLE.
4129 if (idle
!= CPU_NOT_IDLE
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
4130 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
4133 schedstat_inc(sd
, lb_count
[idle
]);
4137 group
= find_busiest_group(sd
, this_cpu
, &imbalance
, idle
, &sd_idle
,
4144 schedstat_inc(sd
, lb_nobusyg
[idle
]);
4148 busiest
= find_busiest_queue(group
, idle
, imbalance
, cpus
);
4150 schedstat_inc(sd
, lb_nobusyq
[idle
]);
4154 BUG_ON(busiest
== this_rq
);
4156 schedstat_add(sd
, lb_imbalance
[idle
], imbalance
);
4159 if (busiest
->nr_running
> 1) {
4161 * Attempt to move tasks. If find_busiest_group has found
4162 * an imbalance but busiest->nr_running <= 1, the group is
4163 * still unbalanced. ld_moved simply stays zero, so it is
4164 * correctly treated as an imbalance.
4166 local_irq_save(flags
);
4167 double_rq_lock(this_rq
, busiest
);
4168 ld_moved
= move_tasks(this_rq
, this_cpu
, busiest
,
4169 imbalance
, sd
, idle
, &all_pinned
);
4170 double_rq_unlock(this_rq
, busiest
);
4171 local_irq_restore(flags
);
4174 * some other cpu did the load balance for us.
4176 if (ld_moved
&& this_cpu
!= smp_processor_id())
4177 resched_cpu(this_cpu
);
4179 /* All tasks on this runqueue were pinned by CPU affinity */
4180 if (unlikely(all_pinned
)) {
4181 cpumask_clear_cpu(cpu_of(busiest
), cpus
);
4182 if (!cpumask_empty(cpus
))
4189 schedstat_inc(sd
, lb_failed
[idle
]);
4190 sd
->nr_balance_failed
++;
4192 if (unlikely(sd
->nr_balance_failed
> sd
->cache_nice_tries
+2)) {
4194 spin_lock_irqsave(&busiest
->lock
, flags
);
4196 /* don't kick the migration_thread, if the curr
4197 * task on busiest cpu can't be moved to this_cpu
4199 if (!cpumask_test_cpu(this_cpu
,
4200 &busiest
->curr
->cpus_allowed
)) {
4201 spin_unlock_irqrestore(&busiest
->lock
, flags
);
4203 goto out_one_pinned
;
4206 if (!busiest
->active_balance
) {
4207 busiest
->active_balance
= 1;
4208 busiest
->push_cpu
= this_cpu
;
4211 spin_unlock_irqrestore(&busiest
->lock
, flags
);
4213 wake_up_process(busiest
->migration_thread
);
4216 * We've kicked active balancing, reset the failure
4219 sd
->nr_balance_failed
= sd
->cache_nice_tries
+1;
4222 sd
->nr_balance_failed
= 0;
4224 if (likely(!active_balance
)) {
4225 /* We were unbalanced, so reset the balancing interval */
4226 sd
->balance_interval
= sd
->min_interval
;
4229 * If we've begun active balancing, start to back off. This
4230 * case may not be covered by the all_pinned logic if there
4231 * is only 1 task on the busy runqueue (because we don't call
4234 if (sd
->balance_interval
< sd
->max_interval
)
4235 sd
->balance_interval
*= 2;
4238 if (!ld_moved
&& !sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
4239 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
4245 schedstat_inc(sd
, lb_balanced
[idle
]);
4247 sd
->nr_balance_failed
= 0;
4250 /* tune up the balancing interval */
4251 if ((all_pinned
&& sd
->balance_interval
< MAX_PINNED_INTERVAL
) ||
4252 (sd
->balance_interval
< sd
->max_interval
))
4253 sd
->balance_interval
*= 2;
4255 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
4256 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
4267 * Check this_cpu to ensure it is balanced within domain. Attempt to move
4268 * tasks if there is an imbalance.
4270 * Called from schedule when this_rq is about to become idle (CPU_NEWLY_IDLE).
4271 * this_rq is locked.
4274 load_balance_newidle(int this_cpu
, struct rq
*this_rq
, struct sched_domain
*sd
)
4276 struct sched_group
*group
;
4277 struct rq
*busiest
= NULL
;
4278 unsigned long imbalance
;
4282 struct cpumask
*cpus
= __get_cpu_var(load_balance_tmpmask
);
4284 cpumask_copy(cpus
, cpu_active_mask
);
4287 * When power savings policy is enabled for the parent domain, idle
4288 * sibling can pick up load irrespective of busy siblings. In this case,
4289 * let the state of idle sibling percolate up as IDLE, instead of
4290 * portraying it as CPU_NOT_IDLE.
4292 if (sd
->flags
& SD_SHARE_CPUPOWER
&&
4293 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
4296 schedstat_inc(sd
, lb_count
[CPU_NEWLY_IDLE
]);
4298 update_shares_locked(this_rq
, sd
);
4299 group
= find_busiest_group(sd
, this_cpu
, &imbalance
, CPU_NEWLY_IDLE
,
4300 &sd_idle
, cpus
, NULL
);
4302 schedstat_inc(sd
, lb_nobusyg
[CPU_NEWLY_IDLE
]);
4306 busiest
= find_busiest_queue(group
, CPU_NEWLY_IDLE
, imbalance
, cpus
);
4308 schedstat_inc(sd
, lb_nobusyq
[CPU_NEWLY_IDLE
]);
4312 BUG_ON(busiest
== this_rq
);
4314 schedstat_add(sd
, lb_imbalance
[CPU_NEWLY_IDLE
], imbalance
);
4317 if (busiest
->nr_running
> 1) {
4318 /* Attempt to move tasks */
4319 double_lock_balance(this_rq
, busiest
);
4320 /* this_rq->clock is already updated */
4321 update_rq_clock(busiest
);
4322 ld_moved
= move_tasks(this_rq
, this_cpu
, busiest
,
4323 imbalance
, sd
, CPU_NEWLY_IDLE
,
4325 double_unlock_balance(this_rq
, busiest
);
4327 if (unlikely(all_pinned
)) {
4328 cpumask_clear_cpu(cpu_of(busiest
), cpus
);
4329 if (!cpumask_empty(cpus
))
4335 int active_balance
= 0;
4337 schedstat_inc(sd
, lb_failed
[CPU_NEWLY_IDLE
]);
4338 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
4339 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
4342 if (sched_mc_power_savings
< POWERSAVINGS_BALANCE_WAKEUP
)
4345 if (sd
->nr_balance_failed
++ < 2)
4349 * The only task running in a non-idle cpu can be moved to this
4350 * cpu in an attempt to completely freeup the other CPU
4351 * package. The same method used to move task in load_balance()
4352 * have been extended for load_balance_newidle() to speedup
4353 * consolidation at sched_mc=POWERSAVINGS_BALANCE_WAKEUP (2)
4355 * The package power saving logic comes from
4356 * find_busiest_group(). If there are no imbalance, then
4357 * f_b_g() will return NULL. However when sched_mc={1,2} then
4358 * f_b_g() will select a group from which a running task may be
4359 * pulled to this cpu in order to make the other package idle.
4360 * If there is no opportunity to make a package idle and if
4361 * there are no imbalance, then f_b_g() will return NULL and no
4362 * action will be taken in load_balance_newidle().
4364 * Under normal task pull operation due to imbalance, there
4365 * will be more than one task in the source run queue and
4366 * move_tasks() will succeed. ld_moved will be true and this
4367 * active balance code will not be triggered.
4370 /* Lock busiest in correct order while this_rq is held */
4371 double_lock_balance(this_rq
, busiest
);
4374 * don't kick the migration_thread, if the curr
4375 * task on busiest cpu can't be moved to this_cpu
4377 if (!cpumask_test_cpu(this_cpu
, &busiest
->curr
->cpus_allowed
)) {
4378 double_unlock_balance(this_rq
, busiest
);
4383 if (!busiest
->active_balance
) {
4384 busiest
->active_balance
= 1;
4385 busiest
->push_cpu
= this_cpu
;
4389 double_unlock_balance(this_rq
, busiest
);
4391 * Should not call ttwu while holding a rq->lock
4393 spin_unlock(&this_rq
->lock
);
4395 wake_up_process(busiest
->migration_thread
);
4396 spin_lock(&this_rq
->lock
);
4399 sd
->nr_balance_failed
= 0;
4401 update_shares_locked(this_rq
, sd
);
4405 schedstat_inc(sd
, lb_balanced
[CPU_NEWLY_IDLE
]);
4406 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
4407 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
4409 sd
->nr_balance_failed
= 0;
4415 * idle_balance is called by schedule() if this_cpu is about to become
4416 * idle. Attempts to pull tasks from other CPUs.
4418 static void idle_balance(int this_cpu
, struct rq
*this_rq
)
4420 struct sched_domain
*sd
;
4421 int pulled_task
= 0;
4422 unsigned long next_balance
= jiffies
+ HZ
;
4424 this_rq
->idle_stamp
= this_rq
->clock
;
4426 if (this_rq
->avg_idle
< sysctl_sched_migration_cost
)
4429 for_each_domain(this_cpu
, sd
) {
4430 unsigned long interval
;
4432 if (!(sd
->flags
& SD_LOAD_BALANCE
))
4435 if (sd
->flags
& SD_BALANCE_NEWIDLE
)
4436 /* If we've pulled tasks over stop searching: */
4437 pulled_task
= load_balance_newidle(this_cpu
, this_rq
,
4440 interval
= msecs_to_jiffies(sd
->balance_interval
);
4441 if (time_after(next_balance
, sd
->last_balance
+ interval
))
4442 next_balance
= sd
->last_balance
+ interval
;
4444 this_rq
->idle_stamp
= 0;
4448 if (pulled_task
|| time_after(jiffies
, this_rq
->next_balance
)) {
4450 * We are going idle. next_balance may be set based on
4451 * a busy processor. So reset next_balance.
4453 this_rq
->next_balance
= next_balance
;
4458 * active_load_balance is run by migration threads. It pushes running tasks
4459 * off the busiest CPU onto idle CPUs. It requires at least 1 task to be
4460 * running on each physical CPU where possible, and avoids physical /
4461 * logical imbalances.
4463 * Called with busiest_rq locked.
4465 static void active_load_balance(struct rq
*busiest_rq
, int busiest_cpu
)
4467 int target_cpu
= busiest_rq
->push_cpu
;
4468 struct sched_domain
*sd
;
4469 struct rq
*target_rq
;
4471 /* Is there any task to move? */
4472 if (busiest_rq
->nr_running
<= 1)
4475 target_rq
= cpu_rq(target_cpu
);
4478 * This condition is "impossible", if it occurs
4479 * we need to fix it. Originally reported by
4480 * Bjorn Helgaas on a 128-cpu setup.
4482 BUG_ON(busiest_rq
== target_rq
);
4484 /* move a task from busiest_rq to target_rq */
4485 double_lock_balance(busiest_rq
, target_rq
);
4486 update_rq_clock(busiest_rq
);
4487 update_rq_clock(target_rq
);
4489 /* Search for an sd spanning us and the target CPU. */
4490 for_each_domain(target_cpu
, sd
) {
4491 if ((sd
->flags
& SD_LOAD_BALANCE
) &&
4492 cpumask_test_cpu(busiest_cpu
, sched_domain_span(sd
)))
4497 schedstat_inc(sd
, alb_count
);
4499 if (move_one_task(target_rq
, target_cpu
, busiest_rq
,
4501 schedstat_inc(sd
, alb_pushed
);
4503 schedstat_inc(sd
, alb_failed
);
4505 double_unlock_balance(busiest_rq
, target_rq
);
4510 atomic_t load_balancer
;
4511 cpumask_var_t cpu_mask
;
4512 cpumask_var_t ilb_grp_nohz_mask
;
4513 } nohz ____cacheline_aligned
= {
4514 .load_balancer
= ATOMIC_INIT(-1),
4517 int get_nohz_load_balancer(void)
4519 return atomic_read(&nohz
.load_balancer
);
4522 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
4524 * lowest_flag_domain - Return lowest sched_domain containing flag.
4525 * @cpu: The cpu whose lowest level of sched domain is to
4527 * @flag: The flag to check for the lowest sched_domain
4528 * for the given cpu.
4530 * Returns the lowest sched_domain of a cpu which contains the given flag.
4532 static inline struct sched_domain
*lowest_flag_domain(int cpu
, int flag
)
4534 struct sched_domain
*sd
;
4536 for_each_domain(cpu
, sd
)
4537 if (sd
&& (sd
->flags
& flag
))
4544 * for_each_flag_domain - Iterates over sched_domains containing the flag.
4545 * @cpu: The cpu whose domains we're iterating over.
4546 * @sd: variable holding the value of the power_savings_sd
4548 * @flag: The flag to filter the sched_domains to be iterated.
4550 * Iterates over all the scheduler domains for a given cpu that has the 'flag'
4551 * set, starting from the lowest sched_domain to the highest.
4553 #define for_each_flag_domain(cpu, sd, flag) \
4554 for (sd = lowest_flag_domain(cpu, flag); \
4555 (sd && (sd->flags & flag)); sd = sd->parent)
4558 * is_semi_idle_group - Checks if the given sched_group is semi-idle.
4559 * @ilb_group: group to be checked for semi-idleness
4561 * Returns: 1 if the group is semi-idle. 0 otherwise.
4563 * We define a sched_group to be semi idle if it has atleast one idle-CPU
4564 * and atleast one non-idle CPU. This helper function checks if the given
4565 * sched_group is semi-idle or not.
4567 static inline int is_semi_idle_group(struct sched_group
*ilb_group
)
4569 cpumask_and(nohz
.ilb_grp_nohz_mask
, nohz
.cpu_mask
,
4570 sched_group_cpus(ilb_group
));
4573 * A sched_group is semi-idle when it has atleast one busy cpu
4574 * and atleast one idle cpu.
4576 if (cpumask_empty(nohz
.ilb_grp_nohz_mask
))
4579 if (cpumask_equal(nohz
.ilb_grp_nohz_mask
, sched_group_cpus(ilb_group
)))
4585 * find_new_ilb - Finds the optimum idle load balancer for nomination.
4586 * @cpu: The cpu which is nominating a new idle_load_balancer.
4588 * Returns: Returns the id of the idle load balancer if it exists,
4589 * Else, returns >= nr_cpu_ids.
4591 * This algorithm picks the idle load balancer such that it belongs to a
4592 * semi-idle powersavings sched_domain. The idea is to try and avoid
4593 * completely idle packages/cores just for the purpose of idle load balancing
4594 * when there are other idle cpu's which are better suited for that job.
4596 static int find_new_ilb(int cpu
)
4598 struct sched_domain
*sd
;
4599 struct sched_group
*ilb_group
;
4602 * Have idle load balancer selection from semi-idle packages only
4603 * when power-aware load balancing is enabled
4605 if (!(sched_smt_power_savings
|| sched_mc_power_savings
))
4609 * Optimize for the case when we have no idle CPUs or only one
4610 * idle CPU. Don't walk the sched_domain hierarchy in such cases
4612 if (cpumask_weight(nohz
.cpu_mask
) < 2)
4615 for_each_flag_domain(cpu
, sd
, SD_POWERSAVINGS_BALANCE
) {
4616 ilb_group
= sd
->groups
;
4619 if (is_semi_idle_group(ilb_group
))
4620 return cpumask_first(nohz
.ilb_grp_nohz_mask
);
4622 ilb_group
= ilb_group
->next
;
4624 } while (ilb_group
!= sd
->groups
);
4628 return cpumask_first(nohz
.cpu_mask
);
4630 #else /* (CONFIG_SCHED_MC || CONFIG_SCHED_SMT) */
4631 static inline int find_new_ilb(int call_cpu
)
4633 return cpumask_first(nohz
.cpu_mask
);
4638 * This routine will try to nominate the ilb (idle load balancing)
4639 * owner among the cpus whose ticks are stopped. ilb owner will do the idle
4640 * load balancing on behalf of all those cpus. If all the cpus in the system
4641 * go into this tickless mode, then there will be no ilb owner (as there is
4642 * no need for one) and all the cpus will sleep till the next wakeup event
4645 * For the ilb owner, tick is not stopped. And this tick will be used
4646 * for idle load balancing. ilb owner will still be part of
4649 * While stopping the tick, this cpu will become the ilb owner if there
4650 * is no other owner. And will be the owner till that cpu becomes busy
4651 * or if all cpus in the system stop their ticks at which point
4652 * there is no need for ilb owner.
4654 * When the ilb owner becomes busy, it nominates another owner, during the
4655 * next busy scheduler_tick()
4657 int select_nohz_load_balancer(int stop_tick
)
4659 int cpu
= smp_processor_id();
4662 cpu_rq(cpu
)->in_nohz_recently
= 1;
4664 if (!cpu_active(cpu
)) {
4665 if (atomic_read(&nohz
.load_balancer
) != cpu
)
4669 * If we are going offline and still the leader,
4672 if (atomic_cmpxchg(&nohz
.load_balancer
, cpu
, -1) != cpu
)
4678 cpumask_set_cpu(cpu
, nohz
.cpu_mask
);
4680 /* time for ilb owner also to sleep */
4681 if (cpumask_weight(nohz
.cpu_mask
) == num_active_cpus()) {
4682 if (atomic_read(&nohz
.load_balancer
) == cpu
)
4683 atomic_set(&nohz
.load_balancer
, -1);
4687 if (atomic_read(&nohz
.load_balancer
) == -1) {
4688 /* make me the ilb owner */
4689 if (atomic_cmpxchg(&nohz
.load_balancer
, -1, cpu
) == -1)
4691 } else if (atomic_read(&nohz
.load_balancer
) == cpu
) {
4694 if (!(sched_smt_power_savings
||
4695 sched_mc_power_savings
))
4698 * Check to see if there is a more power-efficient
4701 new_ilb
= find_new_ilb(cpu
);
4702 if (new_ilb
< nr_cpu_ids
&& new_ilb
!= cpu
) {
4703 atomic_set(&nohz
.load_balancer
, -1);
4704 resched_cpu(new_ilb
);
4710 if (!cpumask_test_cpu(cpu
, nohz
.cpu_mask
))
4713 cpumask_clear_cpu(cpu
, nohz
.cpu_mask
);
4715 if (atomic_read(&nohz
.load_balancer
) == cpu
)
4716 if (atomic_cmpxchg(&nohz
.load_balancer
, cpu
, -1) != cpu
)
4723 static DEFINE_SPINLOCK(balancing
);
4726 * It checks each scheduling domain to see if it is due to be balanced,
4727 * and initiates a balancing operation if so.
4729 * Balancing parameters are set up in arch_init_sched_domains.
4731 static void rebalance_domains(int cpu
, enum cpu_idle_type idle
)
4734 struct rq
*rq
= cpu_rq(cpu
);
4735 unsigned long interval
;
4736 struct sched_domain
*sd
;
4737 /* Earliest time when we have to do rebalance again */
4738 unsigned long next_balance
= jiffies
+ 60*HZ
;
4739 int update_next_balance
= 0;
4742 for_each_domain(cpu
, sd
) {
4743 if (!(sd
->flags
& SD_LOAD_BALANCE
))
4746 interval
= sd
->balance_interval
;
4747 if (idle
!= CPU_IDLE
)
4748 interval
*= sd
->busy_factor
;
4750 /* scale ms to jiffies */
4751 interval
= msecs_to_jiffies(interval
);
4752 if (unlikely(!interval
))
4754 if (interval
> HZ
*NR_CPUS
/10)
4755 interval
= HZ
*NR_CPUS
/10;
4757 need_serialize
= sd
->flags
& SD_SERIALIZE
;
4759 if (need_serialize
) {
4760 if (!spin_trylock(&balancing
))
4764 if (time_after_eq(jiffies
, sd
->last_balance
+ interval
)) {
4765 if (load_balance(cpu
, rq
, sd
, idle
, &balance
)) {
4767 * We've pulled tasks over so either we're no
4768 * longer idle, or one of our SMT siblings is
4771 idle
= CPU_NOT_IDLE
;
4773 sd
->last_balance
= jiffies
;
4776 spin_unlock(&balancing
);
4778 if (time_after(next_balance
, sd
->last_balance
+ interval
)) {
4779 next_balance
= sd
->last_balance
+ interval
;
4780 update_next_balance
= 1;
4784 * Stop the load balance at this level. There is another
4785 * CPU in our sched group which is doing load balancing more
4793 * next_balance will be updated only when there is a need.
4794 * When the cpu is attached to null domain for ex, it will not be
4797 if (likely(update_next_balance
))
4798 rq
->next_balance
= next_balance
;
4802 * run_rebalance_domains is triggered when needed from the scheduler tick.
4803 * In CONFIG_NO_HZ case, the idle load balance owner will do the
4804 * rebalancing for all the cpus for whom scheduler ticks are stopped.
4806 static void run_rebalance_domains(struct softirq_action
*h
)
4808 int this_cpu
= smp_processor_id();
4809 struct rq
*this_rq
= cpu_rq(this_cpu
);
4810 enum cpu_idle_type idle
= this_rq
->idle_at_tick
?
4811 CPU_IDLE
: CPU_NOT_IDLE
;
4813 rebalance_domains(this_cpu
, idle
);
4817 * If this cpu is the owner for idle load balancing, then do the
4818 * balancing on behalf of the other idle cpus whose ticks are
4821 if (this_rq
->idle_at_tick
&&
4822 atomic_read(&nohz
.load_balancer
) == this_cpu
) {
4826 for_each_cpu(balance_cpu
, nohz
.cpu_mask
) {
4827 if (balance_cpu
== this_cpu
)
4831 * If this cpu gets work to do, stop the load balancing
4832 * work being done for other cpus. Next load
4833 * balancing owner will pick it up.
4838 rebalance_domains(balance_cpu
, CPU_IDLE
);
4840 rq
= cpu_rq(balance_cpu
);
4841 if (time_after(this_rq
->next_balance
, rq
->next_balance
))
4842 this_rq
->next_balance
= rq
->next_balance
;
4848 static inline int on_null_domain(int cpu
)
4850 return !rcu_dereference(cpu_rq(cpu
)->sd
);
4854 * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing.
4856 * In case of CONFIG_NO_HZ, this is the place where we nominate a new
4857 * idle load balancing owner or decide to stop the periodic load balancing,
4858 * if the whole system is idle.
4860 static inline void trigger_load_balance(struct rq
*rq
, int cpu
)
4864 * If we were in the nohz mode recently and busy at the current
4865 * scheduler tick, then check if we need to nominate new idle
4868 if (rq
->in_nohz_recently
&& !rq
->idle_at_tick
) {
4869 rq
->in_nohz_recently
= 0;
4871 if (atomic_read(&nohz
.load_balancer
) == cpu
) {
4872 cpumask_clear_cpu(cpu
, nohz
.cpu_mask
);
4873 atomic_set(&nohz
.load_balancer
, -1);
4876 if (atomic_read(&nohz
.load_balancer
) == -1) {
4877 int ilb
= find_new_ilb(cpu
);
4879 if (ilb
< nr_cpu_ids
)
4885 * If this cpu is idle and doing idle load balancing for all the
4886 * cpus with ticks stopped, is it time for that to stop?
4888 if (rq
->idle_at_tick
&& atomic_read(&nohz
.load_balancer
) == cpu
&&
4889 cpumask_weight(nohz
.cpu_mask
) == num_online_cpus()) {
4895 * If this cpu is idle and the idle load balancing is done by
4896 * someone else, then no need raise the SCHED_SOFTIRQ
4898 if (rq
->idle_at_tick
&& atomic_read(&nohz
.load_balancer
) != cpu
&&
4899 cpumask_test_cpu(cpu
, nohz
.cpu_mask
))
4902 /* Don't need to rebalance while attached to NULL domain */
4903 if (time_after_eq(jiffies
, rq
->next_balance
) &&
4904 likely(!on_null_domain(cpu
)))
4905 raise_softirq(SCHED_SOFTIRQ
);
4908 #else /* CONFIG_SMP */
4911 * on UP we do not need to balance between CPUs:
4913 static inline void idle_balance(int cpu
, struct rq
*rq
)
4919 DEFINE_PER_CPU(struct kernel_stat
, kstat
);
4921 EXPORT_PER_CPU_SYMBOL(kstat
);
4924 * Return any ns on the sched_clock that have not yet been accounted in
4925 * @p in case that task is currently running.
4927 * Called with task_rq_lock() held on @rq.
4929 static u64
do_task_delta_exec(struct task_struct
*p
, struct rq
*rq
)
4933 if (task_current(rq
, p
)) {
4934 update_rq_clock(rq
);
4935 ns
= rq
->clock
- p
->se
.exec_start
;
4943 unsigned long long task_delta_exec(struct task_struct
*p
)
4945 unsigned long flags
;
4949 rq
= task_rq_lock(p
, &flags
);
4950 ns
= do_task_delta_exec(p
, rq
);
4951 task_rq_unlock(rq
, &flags
);
4957 * Return accounted runtime for the task.
4958 * In case the task is currently running, return the runtime plus current's
4959 * pending runtime that have not been accounted yet.
4961 unsigned long long task_sched_runtime(struct task_struct
*p
)
4963 unsigned long flags
;
4967 rq
= task_rq_lock(p
, &flags
);
4968 ns
= p
->se
.sum_exec_runtime
+ do_task_delta_exec(p
, rq
);
4969 task_rq_unlock(rq
, &flags
);
4975 * Return sum_exec_runtime for the thread group.
4976 * In case the task is currently running, return the sum plus current's
4977 * pending runtime that have not been accounted yet.
4979 * Note that the thread group might have other running tasks as well,
4980 * so the return value not includes other pending runtime that other
4981 * running tasks might have.
4983 unsigned long long thread_group_sched_runtime(struct task_struct
*p
)
4985 struct task_cputime totals
;
4986 unsigned long flags
;
4990 rq
= task_rq_lock(p
, &flags
);
4991 thread_group_cputime(p
, &totals
);
4992 ns
= totals
.sum_exec_runtime
+ do_task_delta_exec(p
, rq
);
4993 task_rq_unlock(rq
, &flags
);
4999 * Account user cpu time to a process.
5000 * @p: the process that the cpu time gets accounted to
5001 * @cputime: the cpu time spent in user space since the last update
5002 * @cputime_scaled: cputime scaled by cpu frequency
5004 void account_user_time(struct task_struct
*p
, cputime_t cputime
,
5005 cputime_t cputime_scaled
)
5007 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
5010 /* Add user time to process. */
5011 p
->utime
= cputime_add(p
->utime
, cputime
);
5012 p
->utimescaled
= cputime_add(p
->utimescaled
, cputime_scaled
);
5013 account_group_user_time(p
, cputime
);
5015 /* Add user time to cpustat. */
5016 tmp
= cputime_to_cputime64(cputime
);
5017 if (TASK_NICE(p
) > 0)
5018 cpustat
->nice
= cputime64_add(cpustat
->nice
, tmp
);
5020 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
5022 cpuacct_update_stats(p
, CPUACCT_STAT_USER
, cputime
);
5023 /* Account for user time used */
5024 acct_update_integrals(p
);
5028 * Account guest cpu time to a process.
5029 * @p: the process that the cpu time gets accounted to
5030 * @cputime: the cpu time spent in virtual machine since the last update
5031 * @cputime_scaled: cputime scaled by cpu frequency
5033 static void account_guest_time(struct task_struct
*p
, cputime_t cputime
,
5034 cputime_t cputime_scaled
)
5037 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
5039 tmp
= cputime_to_cputime64(cputime
);
5041 /* Add guest time to process. */
5042 p
->utime
= cputime_add(p
->utime
, cputime
);
5043 p
->utimescaled
= cputime_add(p
->utimescaled
, cputime_scaled
);
5044 account_group_user_time(p
, cputime
);
5045 p
->gtime
= cputime_add(p
->gtime
, cputime
);
5047 /* Add guest time to cpustat. */
5048 if (TASK_NICE(p
) > 0) {
5049 cpustat
->nice
= cputime64_add(cpustat
->nice
, tmp
);
5050 cpustat
->guest_nice
= cputime64_add(cpustat
->guest_nice
, tmp
);
5052 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
5053 cpustat
->guest
= cputime64_add(cpustat
->guest
, tmp
);
5058 * Account system cpu time to a process.
5059 * @p: the process that the cpu time gets accounted to
5060 * @hardirq_offset: the offset to subtract from hardirq_count()
5061 * @cputime: the cpu time spent in kernel space since the last update
5062 * @cputime_scaled: cputime scaled by cpu frequency
5064 void account_system_time(struct task_struct
*p
, int hardirq_offset
,
5065 cputime_t cputime
, cputime_t cputime_scaled
)
5067 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
5070 if ((p
->flags
& PF_VCPU
) && (irq_count() - hardirq_offset
== 0)) {
5071 account_guest_time(p
, cputime
, cputime_scaled
);
5075 /* Add system time to process. */
5076 p
->stime
= cputime_add(p
->stime
, cputime
);
5077 p
->stimescaled
= cputime_add(p
->stimescaled
, cputime_scaled
);
5078 account_group_system_time(p
, cputime
);
5080 /* Add system time to cpustat. */
5081 tmp
= cputime_to_cputime64(cputime
);
5082 if (hardirq_count() - hardirq_offset
)
5083 cpustat
->irq
= cputime64_add(cpustat
->irq
, tmp
);
5084 else if (softirq_count())
5085 cpustat
->softirq
= cputime64_add(cpustat
->softirq
, tmp
);
5087 cpustat
->system
= cputime64_add(cpustat
->system
, tmp
);
5089 cpuacct_update_stats(p
, CPUACCT_STAT_SYSTEM
, cputime
);
5091 /* Account for system time used */
5092 acct_update_integrals(p
);
5096 * Account for involuntary wait time.
5097 * @steal: the cpu time spent in involuntary wait
5099 void account_steal_time(cputime_t cputime
)
5101 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
5102 cputime64_t cputime64
= cputime_to_cputime64(cputime
);
5104 cpustat
->steal
= cputime64_add(cpustat
->steal
, cputime64
);
5108 * Account for idle time.
5109 * @cputime: the cpu time spent in idle wait
5111 void account_idle_time(cputime_t cputime
)
5113 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
5114 cputime64_t cputime64
= cputime_to_cputime64(cputime
);
5115 struct rq
*rq
= this_rq();
5117 if (atomic_read(&rq
->nr_iowait
) > 0)
5118 cpustat
->iowait
= cputime64_add(cpustat
->iowait
, cputime64
);
5120 cpustat
->idle
= cputime64_add(cpustat
->idle
, cputime64
);
5123 #ifndef CONFIG_VIRT_CPU_ACCOUNTING
5126 * Account a single tick of cpu time.
5127 * @p: the process that the cpu time gets accounted to
5128 * @user_tick: indicates if the tick is a user or a system tick
5130 void account_process_tick(struct task_struct
*p
, int user_tick
)
5132 cputime_t one_jiffy_scaled
= cputime_to_scaled(cputime_one_jiffy
);
5133 struct rq
*rq
= this_rq();
5136 account_user_time(p
, cputime_one_jiffy
, one_jiffy_scaled
);
5137 else if ((p
!= rq
->idle
) || (irq_count() != HARDIRQ_OFFSET
))
5138 account_system_time(p
, HARDIRQ_OFFSET
, cputime_one_jiffy
,
5141 account_idle_time(cputime_one_jiffy
);
5145 * Account multiple ticks of steal time.
5146 * @p: the process from which the cpu time has been stolen
5147 * @ticks: number of stolen ticks
5149 void account_steal_ticks(unsigned long ticks
)
5151 account_steal_time(jiffies_to_cputime(ticks
));
5155 * Account multiple ticks of idle time.
5156 * @ticks: number of stolen ticks
5158 void account_idle_ticks(unsigned long ticks
)
5160 account_idle_time(jiffies_to_cputime(ticks
));
5166 * Use precise platform statistics if available:
5168 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
5169 void task_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
5175 void thread_group_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
5177 struct task_cputime cputime
;
5179 thread_group_cputime(p
, &cputime
);
5181 *ut
= cputime
.utime
;
5182 *st
= cputime
.stime
;
5186 #ifndef nsecs_to_cputime
5187 # define nsecs_to_cputime(__nsecs) nsecs_to_jiffies(__nsecs)
5190 void task_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
5192 cputime_t rtime
, utime
= p
->utime
, total
= cputime_add(utime
, p
->stime
);
5195 * Use CFS's precise accounting:
5197 rtime
= nsecs_to_cputime(p
->se
.sum_exec_runtime
);
5202 temp
= (u64
)(rtime
* utime
);
5203 do_div(temp
, total
);
5204 utime
= (cputime_t
)temp
;
5209 * Compare with previous values, to keep monotonicity:
5211 p
->prev_utime
= max(p
->prev_utime
, utime
);
5212 p
->prev_stime
= max(p
->prev_stime
, cputime_sub(rtime
, p
->prev_utime
));
5214 *ut
= p
->prev_utime
;
5215 *st
= p
->prev_stime
;
5219 * Must be called with siglock held.
5221 void thread_group_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
5223 struct signal_struct
*sig
= p
->signal
;
5224 struct task_cputime cputime
;
5225 cputime_t rtime
, utime
, total
;
5227 thread_group_cputime(p
, &cputime
);
5229 total
= cputime_add(cputime
.utime
, cputime
.stime
);
5230 rtime
= nsecs_to_cputime(cputime
.sum_exec_runtime
);
5235 temp
= (u64
)(rtime
* cputime
.utime
);
5236 do_div(temp
, total
);
5237 utime
= (cputime_t
)temp
;
5241 sig
->prev_utime
= max(sig
->prev_utime
, utime
);
5242 sig
->prev_stime
= max(sig
->prev_stime
,
5243 cputime_sub(rtime
, sig
->prev_utime
));
5245 *ut
= sig
->prev_utime
;
5246 *st
= sig
->prev_stime
;
5251 * This function gets called by the timer code, with HZ frequency.
5252 * We call it with interrupts disabled.
5254 * It also gets called by the fork code, when changing the parent's
5257 void scheduler_tick(void)
5259 int cpu
= smp_processor_id();
5260 struct rq
*rq
= cpu_rq(cpu
);
5261 struct task_struct
*curr
= rq
->curr
;
5265 spin_lock(&rq
->lock
);
5266 update_rq_clock(rq
);
5267 update_cpu_load(rq
);
5268 curr
->sched_class
->task_tick(rq
, curr
, 0);
5269 spin_unlock(&rq
->lock
);
5271 perf_event_task_tick(curr
, cpu
);
5274 rq
->idle_at_tick
= idle_cpu(cpu
);
5275 trigger_load_balance(rq
, cpu
);
5279 notrace
unsigned long get_parent_ip(unsigned long addr
)
5281 if (in_lock_functions(addr
)) {
5282 addr
= CALLER_ADDR2
;
5283 if (in_lock_functions(addr
))
5284 addr
= CALLER_ADDR3
;
5289 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
5290 defined(CONFIG_PREEMPT_TRACER))
5292 void __kprobes
add_preempt_count(int val
)
5294 #ifdef CONFIG_DEBUG_PREEMPT
5298 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
5301 preempt_count() += val
;
5302 #ifdef CONFIG_DEBUG_PREEMPT
5304 * Spinlock count overflowing soon?
5306 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK
) >=
5309 if (preempt_count() == val
)
5310 trace_preempt_off(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
5312 EXPORT_SYMBOL(add_preempt_count
);
5314 void __kprobes
sub_preempt_count(int val
)
5316 #ifdef CONFIG_DEBUG_PREEMPT
5320 if (DEBUG_LOCKS_WARN_ON(val
> preempt_count()))
5323 * Is the spinlock portion underflowing?
5325 if (DEBUG_LOCKS_WARN_ON((val
< PREEMPT_MASK
) &&
5326 !(preempt_count() & PREEMPT_MASK
)))
5330 if (preempt_count() == val
)
5331 trace_preempt_on(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
5332 preempt_count() -= val
;
5334 EXPORT_SYMBOL(sub_preempt_count
);
5339 * Print scheduling while atomic bug:
5341 static noinline
void __schedule_bug(struct task_struct
*prev
)
5343 struct pt_regs
*regs
= get_irq_regs();
5345 printk(KERN_ERR
"BUG: scheduling while atomic: %s/%d/0x%08x\n",
5346 prev
->comm
, prev
->pid
, preempt_count());
5348 debug_show_held_locks(prev
);
5350 if (irqs_disabled())
5351 print_irqtrace_events(prev
);
5360 * Various schedule()-time debugging checks and statistics:
5362 static inline void schedule_debug(struct task_struct
*prev
)
5365 * Test if we are atomic. Since do_exit() needs to call into
5366 * schedule() atomically, we ignore that path for now.
5367 * Otherwise, whine if we are scheduling when we should not be.
5369 if (unlikely(in_atomic_preempt_off() && !prev
->exit_state
))
5370 __schedule_bug(prev
);
5372 profile_hit(SCHED_PROFILING
, __builtin_return_address(0));
5374 schedstat_inc(this_rq(), sched_count
);
5375 #ifdef CONFIG_SCHEDSTATS
5376 if (unlikely(prev
->lock_depth
>= 0)) {
5377 schedstat_inc(this_rq(), bkl_count
);
5378 schedstat_inc(prev
, sched_info
.bkl_count
);
5383 static void put_prev_task(struct rq
*rq
, struct task_struct
*prev
)
5385 if (prev
->state
== TASK_RUNNING
) {
5386 u64 runtime
= prev
->se
.sum_exec_runtime
;
5388 runtime
-= prev
->se
.prev_sum_exec_runtime
;
5389 runtime
= min_t(u64
, runtime
, 2*sysctl_sched_migration_cost
);
5392 * In order to avoid avg_overlap growing stale when we are
5393 * indeed overlapping and hence not getting put to sleep, grow
5394 * the avg_overlap on preemption.
5396 * We use the average preemption runtime because that
5397 * correlates to the amount of cache footprint a task can
5400 update_avg(&prev
->se
.avg_overlap
, runtime
);
5402 prev
->sched_class
->put_prev_task(rq
, prev
);
5406 * Pick up the highest-prio task:
5408 static inline struct task_struct
*
5409 pick_next_task(struct rq
*rq
)
5411 const struct sched_class
*class;
5412 struct task_struct
*p
;
5415 * Optimization: we know that if all tasks are in
5416 * the fair class we can call that function directly:
5418 if (likely(rq
->nr_running
== rq
->cfs
.nr_running
)) {
5419 p
= fair_sched_class
.pick_next_task(rq
);
5424 class = sched_class_highest
;
5426 p
= class->pick_next_task(rq
);
5430 * Will never be NULL as the idle class always
5431 * returns a non-NULL p:
5433 class = class->next
;
5438 * schedule() is the main scheduler function.
5440 asmlinkage
void __sched
schedule(void)
5442 struct task_struct
*prev
, *next
;
5443 unsigned long *switch_count
;
5449 cpu
= smp_processor_id();
5453 switch_count
= &prev
->nivcsw
;
5455 release_kernel_lock(prev
);
5456 need_resched_nonpreemptible
:
5458 schedule_debug(prev
);
5460 if (sched_feat(HRTICK
))
5463 spin_lock_irq(&rq
->lock
);
5464 update_rq_clock(rq
);
5465 clear_tsk_need_resched(prev
);
5467 if (prev
->state
&& !(preempt_count() & PREEMPT_ACTIVE
)) {
5468 if (unlikely(signal_pending_state(prev
->state
, prev
)))
5469 prev
->state
= TASK_RUNNING
;
5471 deactivate_task(rq
, prev
, 1);
5472 switch_count
= &prev
->nvcsw
;
5475 pre_schedule(rq
, prev
);
5477 if (unlikely(!rq
->nr_running
))
5478 idle_balance(cpu
, rq
);
5480 put_prev_task(rq
, prev
);
5481 next
= pick_next_task(rq
);
5483 if (likely(prev
!= next
)) {
5484 sched_info_switch(prev
, next
);
5485 perf_event_task_sched_out(prev
, next
, cpu
);
5491 context_switch(rq
, prev
, next
); /* unlocks the rq */
5493 * the context switch might have flipped the stack from under
5494 * us, hence refresh the local variables.
5496 cpu
= smp_processor_id();
5499 spin_unlock_irq(&rq
->lock
);
5503 if (unlikely(reacquire_kernel_lock(current
) < 0))
5504 goto need_resched_nonpreemptible
;
5506 preempt_enable_no_resched();
5510 EXPORT_SYMBOL(schedule
);
5512 #ifdef CONFIG_MUTEX_SPIN_ON_OWNER
5514 * Look out! "owner" is an entirely speculative pointer
5515 * access and not reliable.
5517 int mutex_spin_on_owner(struct mutex
*lock
, struct thread_info
*owner
)
5522 if (!sched_feat(OWNER_SPIN
))
5525 #ifdef CONFIG_DEBUG_PAGEALLOC
5527 * Need to access the cpu field knowing that
5528 * DEBUG_PAGEALLOC could have unmapped it if
5529 * the mutex owner just released it and exited.
5531 if (probe_kernel_address(&owner
->cpu
, cpu
))
5538 * Even if the access succeeded (likely case),
5539 * the cpu field may no longer be valid.
5541 if (cpu
>= nr_cpumask_bits
)
5545 * We need to validate that we can do a
5546 * get_cpu() and that we have the percpu area.
5548 if (!cpu_online(cpu
))
5555 * Owner changed, break to re-assess state.
5557 if (lock
->owner
!= owner
)
5561 * Is that owner really running on that cpu?
5563 if (task_thread_info(rq
->curr
) != owner
|| need_resched())
5573 #ifdef CONFIG_PREEMPT
5575 * this is the entry point to schedule() from in-kernel preemption
5576 * off of preempt_enable. Kernel preemptions off return from interrupt
5577 * occur there and call schedule directly.
5579 asmlinkage
void __sched
preempt_schedule(void)
5581 struct thread_info
*ti
= current_thread_info();
5584 * If there is a non-zero preempt_count or interrupts are disabled,
5585 * we do not want to preempt the current task. Just return..
5587 if (likely(ti
->preempt_count
|| irqs_disabled()))
5591 add_preempt_count(PREEMPT_ACTIVE
);
5593 sub_preempt_count(PREEMPT_ACTIVE
);
5596 * Check again in case we missed a preemption opportunity
5597 * between schedule and now.
5600 } while (need_resched());
5602 EXPORT_SYMBOL(preempt_schedule
);
5605 * this is the entry point to schedule() from kernel preemption
5606 * off of irq context.
5607 * Note, that this is called and return with irqs disabled. This will
5608 * protect us against recursive calling from irq.
5610 asmlinkage
void __sched
preempt_schedule_irq(void)
5612 struct thread_info
*ti
= current_thread_info();
5614 /* Catch callers which need to be fixed */
5615 BUG_ON(ti
->preempt_count
|| !irqs_disabled());
5618 add_preempt_count(PREEMPT_ACTIVE
);
5621 local_irq_disable();
5622 sub_preempt_count(PREEMPT_ACTIVE
);
5625 * Check again in case we missed a preemption opportunity
5626 * between schedule and now.
5629 } while (need_resched());
5632 #endif /* CONFIG_PREEMPT */
5634 int default_wake_function(wait_queue_t
*curr
, unsigned mode
, int wake_flags
,
5637 return try_to_wake_up(curr
->private, mode
, wake_flags
);
5639 EXPORT_SYMBOL(default_wake_function
);
5642 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
5643 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
5644 * number) then we wake all the non-exclusive tasks and one exclusive task.
5646 * There are circumstances in which we can try to wake a task which has already
5647 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
5648 * zero in this (rare) case, and we handle it by continuing to scan the queue.
5650 static void __wake_up_common(wait_queue_head_t
*q
, unsigned int mode
,
5651 int nr_exclusive
, int wake_flags
, void *key
)
5653 wait_queue_t
*curr
, *next
;
5655 list_for_each_entry_safe(curr
, next
, &q
->task_list
, task_list
) {
5656 unsigned flags
= curr
->flags
;
5658 if (curr
->func(curr
, mode
, wake_flags
, key
) &&
5659 (flags
& WQ_FLAG_EXCLUSIVE
) && !--nr_exclusive
)
5665 * __wake_up - wake up threads blocked on a waitqueue.
5667 * @mode: which threads
5668 * @nr_exclusive: how many wake-one or wake-many threads to wake up
5669 * @key: is directly passed to the wakeup function
5671 * It may be assumed that this function implies a write memory barrier before
5672 * changing the task state if and only if any tasks are woken up.
5674 void __wake_up(wait_queue_head_t
*q
, unsigned int mode
,
5675 int nr_exclusive
, void *key
)
5677 unsigned long flags
;
5679 spin_lock_irqsave(&q
->lock
, flags
);
5680 __wake_up_common(q
, mode
, nr_exclusive
, 0, key
);
5681 spin_unlock_irqrestore(&q
->lock
, flags
);
5683 EXPORT_SYMBOL(__wake_up
);
5686 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
5688 void __wake_up_locked(wait_queue_head_t
*q
, unsigned int mode
)
5690 __wake_up_common(q
, mode
, 1, 0, NULL
);
5693 void __wake_up_locked_key(wait_queue_head_t
*q
, unsigned int mode
, void *key
)
5695 __wake_up_common(q
, mode
, 1, 0, key
);
5699 * __wake_up_sync_key - wake up threads blocked on a waitqueue.
5701 * @mode: which threads
5702 * @nr_exclusive: how many wake-one or wake-many threads to wake up
5703 * @key: opaque value to be passed to wakeup targets
5705 * The sync wakeup differs that the waker knows that it will schedule
5706 * away soon, so while the target thread will be woken up, it will not
5707 * be migrated to another CPU - ie. the two threads are 'synchronized'
5708 * with each other. This can prevent needless bouncing between CPUs.
5710 * On UP it can prevent extra preemption.
5712 * It may be assumed that this function implies a write memory barrier before
5713 * changing the task state if and only if any tasks are woken up.
5715 void __wake_up_sync_key(wait_queue_head_t
*q
, unsigned int mode
,
5716 int nr_exclusive
, void *key
)
5718 unsigned long flags
;
5719 int wake_flags
= WF_SYNC
;
5724 if (unlikely(!nr_exclusive
))
5727 spin_lock_irqsave(&q
->lock
, flags
);
5728 __wake_up_common(q
, mode
, nr_exclusive
, wake_flags
, key
);
5729 spin_unlock_irqrestore(&q
->lock
, flags
);
5731 EXPORT_SYMBOL_GPL(__wake_up_sync_key
);
5734 * __wake_up_sync - see __wake_up_sync_key()
5736 void __wake_up_sync(wait_queue_head_t
*q
, unsigned int mode
, int nr_exclusive
)
5738 __wake_up_sync_key(q
, mode
, nr_exclusive
, NULL
);
5740 EXPORT_SYMBOL_GPL(__wake_up_sync
); /* For internal use only */
5743 * complete: - signals a single thread waiting on this completion
5744 * @x: holds the state of this particular completion
5746 * This will wake up a single thread waiting on this completion. Threads will be
5747 * awakened in the same order in which they were queued.
5749 * See also complete_all(), wait_for_completion() and related routines.
5751 * It may be assumed that this function implies a write memory barrier before
5752 * changing the task state if and only if any tasks are woken up.
5754 void complete(struct completion
*x
)
5756 unsigned long flags
;
5758 spin_lock_irqsave(&x
->wait
.lock
, flags
);
5760 __wake_up_common(&x
->wait
, TASK_NORMAL
, 1, 0, NULL
);
5761 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
5763 EXPORT_SYMBOL(complete
);
5766 * complete_all: - signals all threads waiting on this completion
5767 * @x: holds the state of this particular completion
5769 * This will wake up all threads waiting on this particular completion event.
5771 * It may be assumed that this function implies a write memory barrier before
5772 * changing the task state if and only if any tasks are woken up.
5774 void complete_all(struct completion
*x
)
5776 unsigned long flags
;
5778 spin_lock_irqsave(&x
->wait
.lock
, flags
);
5779 x
->done
+= UINT_MAX
/2;
5780 __wake_up_common(&x
->wait
, TASK_NORMAL
, 0, 0, NULL
);
5781 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
5783 EXPORT_SYMBOL(complete_all
);
5785 static inline long __sched
5786 do_wait_for_common(struct completion
*x
, long timeout
, int state
)
5789 DECLARE_WAITQUEUE(wait
, current
);
5791 wait
.flags
|= WQ_FLAG_EXCLUSIVE
;
5792 __add_wait_queue_tail(&x
->wait
, &wait
);
5794 if (signal_pending_state(state
, current
)) {
5795 timeout
= -ERESTARTSYS
;
5798 __set_current_state(state
);
5799 spin_unlock_irq(&x
->wait
.lock
);
5800 timeout
= schedule_timeout(timeout
);
5801 spin_lock_irq(&x
->wait
.lock
);
5802 } while (!x
->done
&& timeout
);
5803 __remove_wait_queue(&x
->wait
, &wait
);
5808 return timeout
?: 1;
5812 wait_for_common(struct completion
*x
, long timeout
, int state
)
5816 spin_lock_irq(&x
->wait
.lock
);
5817 timeout
= do_wait_for_common(x
, timeout
, state
);
5818 spin_unlock_irq(&x
->wait
.lock
);
5823 * wait_for_completion: - waits for completion of a task
5824 * @x: holds the state of this particular completion
5826 * This waits to be signaled for completion of a specific task. It is NOT
5827 * interruptible and there is no timeout.
5829 * See also similar routines (i.e. wait_for_completion_timeout()) with timeout
5830 * and interrupt capability. Also see complete().
5832 void __sched
wait_for_completion(struct completion
*x
)
5834 wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_UNINTERRUPTIBLE
);
5836 EXPORT_SYMBOL(wait_for_completion
);
5839 * wait_for_completion_timeout: - waits for completion of a task (w/timeout)
5840 * @x: holds the state of this particular completion
5841 * @timeout: timeout value in jiffies
5843 * This waits for either a completion of a specific task to be signaled or for a
5844 * specified timeout to expire. The timeout is in jiffies. It is not
5847 unsigned long __sched
5848 wait_for_completion_timeout(struct completion
*x
, unsigned long timeout
)
5850 return wait_for_common(x
, timeout
, TASK_UNINTERRUPTIBLE
);
5852 EXPORT_SYMBOL(wait_for_completion_timeout
);
5855 * wait_for_completion_interruptible: - waits for completion of a task (w/intr)
5856 * @x: holds the state of this particular completion
5858 * This waits for completion of a specific task to be signaled. It is
5861 int __sched
wait_for_completion_interruptible(struct completion
*x
)
5863 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_INTERRUPTIBLE
);
5864 if (t
== -ERESTARTSYS
)
5868 EXPORT_SYMBOL(wait_for_completion_interruptible
);
5871 * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr))
5872 * @x: holds the state of this particular completion
5873 * @timeout: timeout value in jiffies
5875 * This waits for either a completion of a specific task to be signaled or for a
5876 * specified timeout to expire. It is interruptible. The timeout is in jiffies.
5878 unsigned long __sched
5879 wait_for_completion_interruptible_timeout(struct completion
*x
,
5880 unsigned long timeout
)
5882 return wait_for_common(x
, timeout
, TASK_INTERRUPTIBLE
);
5884 EXPORT_SYMBOL(wait_for_completion_interruptible_timeout
);
5887 * wait_for_completion_killable: - waits for completion of a task (killable)
5888 * @x: holds the state of this particular completion
5890 * This waits to be signaled for completion of a specific task. It can be
5891 * interrupted by a kill signal.
5893 int __sched
wait_for_completion_killable(struct completion
*x
)
5895 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_KILLABLE
);
5896 if (t
== -ERESTARTSYS
)
5900 EXPORT_SYMBOL(wait_for_completion_killable
);
5903 * try_wait_for_completion - try to decrement a completion without blocking
5904 * @x: completion structure
5906 * Returns: 0 if a decrement cannot be done without blocking
5907 * 1 if a decrement succeeded.
5909 * If a completion is being used as a counting completion,
5910 * attempt to decrement the counter without blocking. This
5911 * enables us to avoid waiting if the resource the completion
5912 * is protecting is not available.
5914 bool try_wait_for_completion(struct completion
*x
)
5918 spin_lock_irq(&x
->wait
.lock
);
5923 spin_unlock_irq(&x
->wait
.lock
);
5926 EXPORT_SYMBOL(try_wait_for_completion
);
5929 * completion_done - Test to see if a completion has any waiters
5930 * @x: completion structure
5932 * Returns: 0 if there are waiters (wait_for_completion() in progress)
5933 * 1 if there are no waiters.
5936 bool completion_done(struct completion
*x
)
5940 spin_lock_irq(&x
->wait
.lock
);
5943 spin_unlock_irq(&x
->wait
.lock
);
5946 EXPORT_SYMBOL(completion_done
);
5949 sleep_on_common(wait_queue_head_t
*q
, int state
, long timeout
)
5951 unsigned long flags
;
5954 init_waitqueue_entry(&wait
, current
);
5956 __set_current_state(state
);
5958 spin_lock_irqsave(&q
->lock
, flags
);
5959 __add_wait_queue(q
, &wait
);
5960 spin_unlock(&q
->lock
);
5961 timeout
= schedule_timeout(timeout
);
5962 spin_lock_irq(&q
->lock
);
5963 __remove_wait_queue(q
, &wait
);
5964 spin_unlock_irqrestore(&q
->lock
, flags
);
5969 void __sched
interruptible_sleep_on(wait_queue_head_t
*q
)
5971 sleep_on_common(q
, TASK_INTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
5973 EXPORT_SYMBOL(interruptible_sleep_on
);
5976 interruptible_sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
5978 return sleep_on_common(q
, TASK_INTERRUPTIBLE
, timeout
);
5980 EXPORT_SYMBOL(interruptible_sleep_on_timeout
);
5982 void __sched
sleep_on(wait_queue_head_t
*q
)
5984 sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
5986 EXPORT_SYMBOL(sleep_on
);
5988 long __sched
sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
5990 return sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, timeout
);
5992 EXPORT_SYMBOL(sleep_on_timeout
);
5994 #ifdef CONFIG_RT_MUTEXES
5997 * rt_mutex_setprio - set the current priority of a task
5999 * @prio: prio value (kernel-internal form)
6001 * This function changes the 'effective' priority of a task. It does
6002 * not touch ->normal_prio like __setscheduler().
6004 * Used by the rt_mutex code to implement priority inheritance logic.
6006 void rt_mutex_setprio(struct task_struct
*p
, int prio
)
6008 unsigned long flags
;
6009 int oldprio
, on_rq
, running
;
6011 const struct sched_class
*prev_class
= p
->sched_class
;
6013 BUG_ON(prio
< 0 || prio
> MAX_PRIO
);
6015 rq
= task_rq_lock(p
, &flags
);
6016 update_rq_clock(rq
);
6019 on_rq
= p
->se
.on_rq
;
6020 running
= task_current(rq
, p
);
6022 dequeue_task(rq
, p
, 0);
6024 p
->sched_class
->put_prev_task(rq
, p
);
6027 p
->sched_class
= &rt_sched_class
;
6029 p
->sched_class
= &fair_sched_class
;
6034 p
->sched_class
->set_curr_task(rq
);
6036 enqueue_task(rq
, p
, 0);
6038 check_class_changed(rq
, p
, prev_class
, oldprio
, running
);
6040 task_rq_unlock(rq
, &flags
);
6045 void set_user_nice(struct task_struct
*p
, long nice
)
6047 int old_prio
, delta
, on_rq
;
6048 unsigned long flags
;
6051 if (TASK_NICE(p
) == nice
|| nice
< -20 || nice
> 19)
6054 * We have to be careful, if called from sys_setpriority(),
6055 * the task might be in the middle of scheduling on another CPU.
6057 rq
= task_rq_lock(p
, &flags
);
6058 update_rq_clock(rq
);
6060 * The RT priorities are set via sched_setscheduler(), but we still
6061 * allow the 'normal' nice value to be set - but as expected
6062 * it wont have any effect on scheduling until the task is
6063 * SCHED_FIFO/SCHED_RR:
6065 if (task_has_rt_policy(p
)) {
6066 p
->static_prio
= NICE_TO_PRIO(nice
);
6069 on_rq
= p
->se
.on_rq
;
6071 dequeue_task(rq
, p
, 0);
6073 p
->static_prio
= NICE_TO_PRIO(nice
);
6076 p
->prio
= effective_prio(p
);
6077 delta
= p
->prio
- old_prio
;
6080 enqueue_task(rq
, p
, 0);
6082 * If the task increased its priority or is running and
6083 * lowered its priority, then reschedule its CPU:
6085 if (delta
< 0 || (delta
> 0 && task_running(rq
, p
)))
6086 resched_task(rq
->curr
);
6089 task_rq_unlock(rq
, &flags
);
6091 EXPORT_SYMBOL(set_user_nice
);
6094 * can_nice - check if a task can reduce its nice value
6098 int can_nice(const struct task_struct
*p
, const int nice
)
6100 /* convert nice value [19,-20] to rlimit style value [1,40] */
6101 int nice_rlim
= 20 - nice
;
6103 return (nice_rlim
<= p
->signal
->rlim
[RLIMIT_NICE
].rlim_cur
||
6104 capable(CAP_SYS_NICE
));
6107 #ifdef __ARCH_WANT_SYS_NICE
6110 * sys_nice - change the priority of the current process.
6111 * @increment: priority increment
6113 * sys_setpriority is a more generic, but much slower function that
6114 * does similar things.
6116 SYSCALL_DEFINE1(nice
, int, increment
)
6121 * Setpriority might change our priority at the same moment.
6122 * We don't have to worry. Conceptually one call occurs first
6123 * and we have a single winner.
6125 if (increment
< -40)
6130 nice
= TASK_NICE(current
) + increment
;
6136 if (increment
< 0 && !can_nice(current
, nice
))
6139 retval
= security_task_setnice(current
, nice
);
6143 set_user_nice(current
, nice
);
6150 * task_prio - return the priority value of a given task.
6151 * @p: the task in question.
6153 * This is the priority value as seen by users in /proc.
6154 * RT tasks are offset by -200. Normal tasks are centered
6155 * around 0, value goes from -16 to +15.
6157 int task_prio(const struct task_struct
*p
)
6159 return p
->prio
- MAX_RT_PRIO
;
6163 * task_nice - return the nice value of a given task.
6164 * @p: the task in question.
6166 int task_nice(const struct task_struct
*p
)
6168 return TASK_NICE(p
);
6170 EXPORT_SYMBOL(task_nice
);
6173 * idle_cpu - is a given cpu idle currently?
6174 * @cpu: the processor in question.
6176 int idle_cpu(int cpu
)
6178 return cpu_curr(cpu
) == cpu_rq(cpu
)->idle
;
6182 * idle_task - return the idle task for a given cpu.
6183 * @cpu: the processor in question.
6185 struct task_struct
*idle_task(int cpu
)
6187 return cpu_rq(cpu
)->idle
;
6191 * find_process_by_pid - find a process with a matching PID value.
6192 * @pid: the pid in question.
6194 static struct task_struct
*find_process_by_pid(pid_t pid
)
6196 return pid
? find_task_by_vpid(pid
) : current
;
6199 /* Actually do priority change: must hold rq lock. */
6201 __setscheduler(struct rq
*rq
, struct task_struct
*p
, int policy
, int prio
)
6203 BUG_ON(p
->se
.on_rq
);
6206 p
->rt_priority
= prio
;
6207 p
->normal_prio
= normal_prio(p
);
6208 /* we are holding p->pi_lock already */
6209 p
->prio
= rt_mutex_getprio(p
);
6210 if (rt_prio(p
->prio
))
6211 p
->sched_class
= &rt_sched_class
;
6213 p
->sched_class
= &fair_sched_class
;
6218 * check the target process has a UID that matches the current process's
6220 static bool check_same_owner(struct task_struct
*p
)
6222 const struct cred
*cred
= current_cred(), *pcred
;
6226 pcred
= __task_cred(p
);
6227 match
= (cred
->euid
== pcred
->euid
||
6228 cred
->euid
== pcred
->uid
);
6233 static int __sched_setscheduler(struct task_struct
*p
, int policy
,
6234 struct sched_param
*param
, bool user
)
6236 int retval
, oldprio
, oldpolicy
= -1, on_rq
, running
;
6237 unsigned long flags
;
6238 const struct sched_class
*prev_class
= p
->sched_class
;
6242 /* may grab non-irq protected spin_locks */
6243 BUG_ON(in_interrupt());
6245 /* double check policy once rq lock held */
6247 reset_on_fork
= p
->sched_reset_on_fork
;
6248 policy
= oldpolicy
= p
->policy
;
6250 reset_on_fork
= !!(policy
& SCHED_RESET_ON_FORK
);
6251 policy
&= ~SCHED_RESET_ON_FORK
;
6253 if (policy
!= SCHED_FIFO
&& policy
!= SCHED_RR
&&
6254 policy
!= SCHED_NORMAL
&& policy
!= SCHED_BATCH
&&
6255 policy
!= SCHED_IDLE
)
6260 * Valid priorities for SCHED_FIFO and SCHED_RR are
6261 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
6262 * SCHED_BATCH and SCHED_IDLE is 0.
6264 if (param
->sched_priority
< 0 ||
6265 (p
->mm
&& param
->sched_priority
> MAX_USER_RT_PRIO
-1) ||
6266 (!p
->mm
&& param
->sched_priority
> MAX_RT_PRIO
-1))
6268 if (rt_policy(policy
) != (param
->sched_priority
!= 0))
6272 * Allow unprivileged RT tasks to decrease priority:
6274 if (user
&& !capable(CAP_SYS_NICE
)) {
6275 if (rt_policy(policy
)) {
6276 unsigned long rlim_rtprio
;
6278 if (!lock_task_sighand(p
, &flags
))
6280 rlim_rtprio
= p
->signal
->rlim
[RLIMIT_RTPRIO
].rlim_cur
;
6281 unlock_task_sighand(p
, &flags
);
6283 /* can't set/change the rt policy */
6284 if (policy
!= p
->policy
&& !rlim_rtprio
)
6287 /* can't increase priority */
6288 if (param
->sched_priority
> p
->rt_priority
&&
6289 param
->sched_priority
> rlim_rtprio
)
6293 * Like positive nice levels, dont allow tasks to
6294 * move out of SCHED_IDLE either:
6296 if (p
->policy
== SCHED_IDLE
&& policy
!= SCHED_IDLE
)
6299 /* can't change other user's priorities */
6300 if (!check_same_owner(p
))
6303 /* Normal users shall not reset the sched_reset_on_fork flag */
6304 if (p
->sched_reset_on_fork
&& !reset_on_fork
)
6309 #ifdef CONFIG_RT_GROUP_SCHED
6311 * Do not allow realtime tasks into groups that have no runtime
6314 if (rt_bandwidth_enabled() && rt_policy(policy
) &&
6315 task_group(p
)->rt_bandwidth
.rt_runtime
== 0)
6319 retval
= security_task_setscheduler(p
, policy
, param
);
6325 * make sure no PI-waiters arrive (or leave) while we are
6326 * changing the priority of the task:
6328 spin_lock_irqsave(&p
->pi_lock
, flags
);
6330 * To be able to change p->policy safely, the apropriate
6331 * runqueue lock must be held.
6333 rq
= __task_rq_lock(p
);
6334 /* recheck policy now with rq lock held */
6335 if (unlikely(oldpolicy
!= -1 && oldpolicy
!= p
->policy
)) {
6336 policy
= oldpolicy
= -1;
6337 __task_rq_unlock(rq
);
6338 spin_unlock_irqrestore(&p
->pi_lock
, flags
);
6341 update_rq_clock(rq
);
6342 on_rq
= p
->se
.on_rq
;
6343 running
= task_current(rq
, p
);
6345 deactivate_task(rq
, p
, 0);
6347 p
->sched_class
->put_prev_task(rq
, p
);
6349 p
->sched_reset_on_fork
= reset_on_fork
;
6352 __setscheduler(rq
, p
, policy
, param
->sched_priority
);
6355 p
->sched_class
->set_curr_task(rq
);
6357 activate_task(rq
, p
, 0);
6359 check_class_changed(rq
, p
, prev_class
, oldprio
, running
);
6361 __task_rq_unlock(rq
);
6362 spin_unlock_irqrestore(&p
->pi_lock
, flags
);
6364 rt_mutex_adjust_pi(p
);
6370 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
6371 * @p: the task in question.
6372 * @policy: new policy.
6373 * @param: structure containing the new RT priority.
6375 * NOTE that the task may be already dead.
6377 int sched_setscheduler(struct task_struct
*p
, int policy
,
6378 struct sched_param
*param
)
6380 return __sched_setscheduler(p
, policy
, param
, true);
6382 EXPORT_SYMBOL_GPL(sched_setscheduler
);
6385 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
6386 * @p: the task in question.
6387 * @policy: new policy.
6388 * @param: structure containing the new RT priority.
6390 * Just like sched_setscheduler, only don't bother checking if the
6391 * current context has permission. For example, this is needed in
6392 * stop_machine(): we create temporary high priority worker threads,
6393 * but our caller might not have that capability.
6395 int sched_setscheduler_nocheck(struct task_struct
*p
, int policy
,
6396 struct sched_param
*param
)
6398 return __sched_setscheduler(p
, policy
, param
, false);
6402 do_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
6404 struct sched_param lparam
;
6405 struct task_struct
*p
;
6408 if (!param
|| pid
< 0)
6410 if (copy_from_user(&lparam
, param
, sizeof(struct sched_param
)))
6415 p
= find_process_by_pid(pid
);
6417 retval
= sched_setscheduler(p
, policy
, &lparam
);
6424 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
6425 * @pid: the pid in question.
6426 * @policy: new policy.
6427 * @param: structure containing the new RT priority.
6429 SYSCALL_DEFINE3(sched_setscheduler
, pid_t
, pid
, int, policy
,
6430 struct sched_param __user
*, param
)
6432 /* negative values for policy are not valid */
6436 return do_sched_setscheduler(pid
, policy
, param
);
6440 * sys_sched_setparam - set/change the RT priority of a thread
6441 * @pid: the pid in question.
6442 * @param: structure containing the new RT priority.
6444 SYSCALL_DEFINE2(sched_setparam
, pid_t
, pid
, struct sched_param __user
*, param
)
6446 return do_sched_setscheduler(pid
, -1, param
);
6450 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
6451 * @pid: the pid in question.
6453 SYSCALL_DEFINE1(sched_getscheduler
, pid_t
, pid
)
6455 struct task_struct
*p
;
6462 read_lock(&tasklist_lock
);
6463 p
= find_process_by_pid(pid
);
6465 retval
= security_task_getscheduler(p
);
6468 | (p
->sched_reset_on_fork
? SCHED_RESET_ON_FORK
: 0);
6470 read_unlock(&tasklist_lock
);
6475 * sys_sched_getparam - get the RT priority of a thread
6476 * @pid: the pid in question.
6477 * @param: structure containing the RT priority.
6479 SYSCALL_DEFINE2(sched_getparam
, pid_t
, pid
, struct sched_param __user
*, param
)
6481 struct sched_param lp
;
6482 struct task_struct
*p
;
6485 if (!param
|| pid
< 0)
6488 read_lock(&tasklist_lock
);
6489 p
= find_process_by_pid(pid
);
6494 retval
= security_task_getscheduler(p
);
6498 lp
.sched_priority
= p
->rt_priority
;
6499 read_unlock(&tasklist_lock
);
6502 * This one might sleep, we cannot do it with a spinlock held ...
6504 retval
= copy_to_user(param
, &lp
, sizeof(*param
)) ? -EFAULT
: 0;
6509 read_unlock(&tasklist_lock
);
6513 long sched_setaffinity(pid_t pid
, const struct cpumask
*in_mask
)
6515 cpumask_var_t cpus_allowed
, new_mask
;
6516 struct task_struct
*p
;
6520 read_lock(&tasklist_lock
);
6522 p
= find_process_by_pid(pid
);
6524 read_unlock(&tasklist_lock
);
6530 * It is not safe to call set_cpus_allowed with the
6531 * tasklist_lock held. We will bump the task_struct's
6532 * usage count and then drop tasklist_lock.
6535 read_unlock(&tasklist_lock
);
6537 if (!alloc_cpumask_var(&cpus_allowed
, GFP_KERNEL
)) {
6541 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
)) {
6543 goto out_free_cpus_allowed
;
6546 if (!check_same_owner(p
) && !capable(CAP_SYS_NICE
))
6549 retval
= security_task_setscheduler(p
, 0, NULL
);
6553 cpuset_cpus_allowed(p
, cpus_allowed
);
6554 cpumask_and(new_mask
, in_mask
, cpus_allowed
);
6556 retval
= set_cpus_allowed_ptr(p
, new_mask
);
6559 cpuset_cpus_allowed(p
, cpus_allowed
);
6560 if (!cpumask_subset(new_mask
, cpus_allowed
)) {
6562 * We must have raced with a concurrent cpuset
6563 * update. Just reset the cpus_allowed to the
6564 * cpuset's cpus_allowed
6566 cpumask_copy(new_mask
, cpus_allowed
);
6571 free_cpumask_var(new_mask
);
6572 out_free_cpus_allowed
:
6573 free_cpumask_var(cpus_allowed
);
6580 static int get_user_cpu_mask(unsigned long __user
*user_mask_ptr
, unsigned len
,
6581 struct cpumask
*new_mask
)
6583 if (len
< cpumask_size())
6584 cpumask_clear(new_mask
);
6585 else if (len
> cpumask_size())
6586 len
= cpumask_size();
6588 return copy_from_user(new_mask
, user_mask_ptr
, len
) ? -EFAULT
: 0;
6592 * sys_sched_setaffinity - set the cpu affinity of a process
6593 * @pid: pid of the process
6594 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
6595 * @user_mask_ptr: user-space pointer to the new cpu mask
6597 SYSCALL_DEFINE3(sched_setaffinity
, pid_t
, pid
, unsigned int, len
,
6598 unsigned long __user
*, user_mask_ptr
)
6600 cpumask_var_t new_mask
;
6603 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
))
6606 retval
= get_user_cpu_mask(user_mask_ptr
, len
, new_mask
);
6608 retval
= sched_setaffinity(pid
, new_mask
);
6609 free_cpumask_var(new_mask
);
6613 long sched_getaffinity(pid_t pid
, struct cpumask
*mask
)
6615 struct task_struct
*p
;
6616 unsigned long flags
;
6621 read_lock(&tasklist_lock
);
6624 p
= find_process_by_pid(pid
);
6628 retval
= security_task_getscheduler(p
);
6632 rq
= task_rq_lock(p
, &flags
);
6633 cpumask_and(mask
, &p
->cpus_allowed
, cpu_online_mask
);
6634 task_rq_unlock(rq
, &flags
);
6637 read_unlock(&tasklist_lock
);
6644 * sys_sched_getaffinity - get the cpu affinity of a process
6645 * @pid: pid of the process
6646 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
6647 * @user_mask_ptr: user-space pointer to hold the current cpu mask
6649 SYSCALL_DEFINE3(sched_getaffinity
, pid_t
, pid
, unsigned int, len
,
6650 unsigned long __user
*, user_mask_ptr
)
6655 if (len
< cpumask_size())
6658 if (!alloc_cpumask_var(&mask
, GFP_KERNEL
))
6661 ret
= sched_getaffinity(pid
, mask
);
6663 if (copy_to_user(user_mask_ptr
, mask
, cpumask_size()))
6666 ret
= cpumask_size();
6668 free_cpumask_var(mask
);
6674 * sys_sched_yield - yield the current processor to other threads.
6676 * This function yields the current CPU to other tasks. If there are no
6677 * other threads running on this CPU then this function will return.
6679 SYSCALL_DEFINE0(sched_yield
)
6681 struct rq
*rq
= this_rq_lock();
6683 schedstat_inc(rq
, yld_count
);
6684 current
->sched_class
->yield_task(rq
);
6687 * Since we are going to call schedule() anyway, there's
6688 * no need to preempt or enable interrupts:
6690 __release(rq
->lock
);
6691 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
6692 _raw_spin_unlock(&rq
->lock
);
6693 preempt_enable_no_resched();
6700 static inline int should_resched(void)
6702 return need_resched() && !(preempt_count() & PREEMPT_ACTIVE
);
6705 static void __cond_resched(void)
6707 add_preempt_count(PREEMPT_ACTIVE
);
6709 sub_preempt_count(PREEMPT_ACTIVE
);
6712 int __sched
_cond_resched(void)
6714 if (should_resched()) {
6720 EXPORT_SYMBOL(_cond_resched
);
6723 * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
6724 * call schedule, and on return reacquire the lock.
6726 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
6727 * operations here to prevent schedule() from being called twice (once via
6728 * spin_unlock(), once by hand).
6730 int __cond_resched_lock(spinlock_t
*lock
)
6732 int resched
= should_resched();
6735 lockdep_assert_held(lock
);
6737 if (spin_needbreak(lock
) || resched
) {
6748 EXPORT_SYMBOL(__cond_resched_lock
);
6750 int __sched
__cond_resched_softirq(void)
6752 BUG_ON(!in_softirq());
6754 if (should_resched()) {
6762 EXPORT_SYMBOL(__cond_resched_softirq
);
6765 * yield - yield the current processor to other threads.
6767 * This is a shortcut for kernel-space yielding - it marks the
6768 * thread runnable and calls sys_sched_yield().
6770 void __sched
yield(void)
6772 set_current_state(TASK_RUNNING
);
6775 EXPORT_SYMBOL(yield
);
6778 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
6779 * that process accounting knows that this is a task in IO wait state.
6781 void __sched
io_schedule(void)
6783 struct rq
*rq
= raw_rq();
6785 delayacct_blkio_start();
6786 atomic_inc(&rq
->nr_iowait
);
6787 current
->in_iowait
= 1;
6789 current
->in_iowait
= 0;
6790 atomic_dec(&rq
->nr_iowait
);
6791 delayacct_blkio_end();
6793 EXPORT_SYMBOL(io_schedule
);
6795 long __sched
io_schedule_timeout(long timeout
)
6797 struct rq
*rq
= raw_rq();
6800 delayacct_blkio_start();
6801 atomic_inc(&rq
->nr_iowait
);
6802 current
->in_iowait
= 1;
6803 ret
= schedule_timeout(timeout
);
6804 current
->in_iowait
= 0;
6805 atomic_dec(&rq
->nr_iowait
);
6806 delayacct_blkio_end();
6811 * sys_sched_get_priority_max - return maximum RT priority.
6812 * @policy: scheduling class.
6814 * this syscall returns the maximum rt_priority that can be used
6815 * by a given scheduling class.
6817 SYSCALL_DEFINE1(sched_get_priority_max
, int, policy
)
6824 ret
= MAX_USER_RT_PRIO
-1;
6836 * sys_sched_get_priority_min - return minimum RT priority.
6837 * @policy: scheduling class.
6839 * this syscall returns the minimum rt_priority that can be used
6840 * by a given scheduling class.
6842 SYSCALL_DEFINE1(sched_get_priority_min
, int, policy
)
6860 * sys_sched_rr_get_interval - return the default timeslice of a process.
6861 * @pid: pid of the process.
6862 * @interval: userspace pointer to the timeslice value.
6864 * this syscall writes the default timeslice value of a given process
6865 * into the user-space timespec buffer. A value of '0' means infinity.
6867 SYSCALL_DEFINE2(sched_rr_get_interval
, pid_t
, pid
,
6868 struct timespec __user
*, interval
)
6870 struct task_struct
*p
;
6871 unsigned int time_slice
;
6872 unsigned long flags
;
6881 read_lock(&tasklist_lock
);
6882 p
= find_process_by_pid(pid
);
6886 retval
= security_task_getscheduler(p
);
6890 rq
= task_rq_lock(p
, &flags
);
6891 time_slice
= p
->sched_class
->get_rr_interval(rq
, p
);
6892 task_rq_unlock(rq
, &flags
);
6894 read_unlock(&tasklist_lock
);
6895 jiffies_to_timespec(time_slice
, &t
);
6896 retval
= copy_to_user(interval
, &t
, sizeof(t
)) ? -EFAULT
: 0;
6900 read_unlock(&tasklist_lock
);
6904 static const char stat_nam
[] = TASK_STATE_TO_CHAR_STR
;
6906 void sched_show_task(struct task_struct
*p
)
6908 unsigned long free
= 0;
6911 state
= p
->state
? __ffs(p
->state
) + 1 : 0;
6912 printk(KERN_INFO
"%-13.13s %c", p
->comm
,
6913 state
< sizeof(stat_nam
) - 1 ? stat_nam
[state
] : '?');
6914 #if BITS_PER_LONG == 32
6915 if (state
== TASK_RUNNING
)
6916 printk(KERN_CONT
" running ");
6918 printk(KERN_CONT
" %08lx ", thread_saved_pc(p
));
6920 if (state
== TASK_RUNNING
)
6921 printk(KERN_CONT
" running task ");
6923 printk(KERN_CONT
" %016lx ", thread_saved_pc(p
));
6925 #ifdef CONFIG_DEBUG_STACK_USAGE
6926 free
= stack_not_used(p
);
6928 printk(KERN_CONT
"%5lu %5d %6d 0x%08lx\n", free
,
6929 task_pid_nr(p
), task_pid_nr(p
->real_parent
),
6930 (unsigned long)task_thread_info(p
)->flags
);
6932 show_stack(p
, NULL
);
6935 void show_state_filter(unsigned long state_filter
)
6937 struct task_struct
*g
, *p
;
6939 #if BITS_PER_LONG == 32
6941 " task PC stack pid father\n");
6944 " task PC stack pid father\n");
6946 read_lock(&tasklist_lock
);
6947 do_each_thread(g
, p
) {
6949 * reset the NMI-timeout, listing all files on a slow
6950 * console might take alot of time:
6952 touch_nmi_watchdog();
6953 if (!state_filter
|| (p
->state
& state_filter
))
6955 } while_each_thread(g
, p
);
6957 touch_all_softlockup_watchdogs();
6959 #ifdef CONFIG_SCHED_DEBUG
6960 sysrq_sched_debug_show();
6962 read_unlock(&tasklist_lock
);
6964 * Only show locks if all tasks are dumped:
6967 debug_show_all_locks();
6970 void __cpuinit
init_idle_bootup_task(struct task_struct
*idle
)
6972 idle
->sched_class
= &idle_sched_class
;
6976 * init_idle - set up an idle thread for a given CPU
6977 * @idle: task in question
6978 * @cpu: cpu the idle task belongs to
6980 * NOTE: this function does not set the idle thread's NEED_RESCHED
6981 * flag, to make booting more robust.
6983 void __cpuinit
init_idle(struct task_struct
*idle
, int cpu
)
6985 struct rq
*rq
= cpu_rq(cpu
);
6986 unsigned long flags
;
6988 spin_lock_irqsave(&rq
->lock
, flags
);
6991 idle
->se
.exec_start
= sched_clock();
6993 cpumask_copy(&idle
->cpus_allowed
, cpumask_of(cpu
));
6994 __set_task_cpu(idle
, cpu
);
6996 rq
->curr
= rq
->idle
= idle
;
6997 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
7000 spin_unlock_irqrestore(&rq
->lock
, flags
);
7002 /* Set the preempt count _outside_ the spinlocks! */
7003 #if defined(CONFIG_PREEMPT)
7004 task_thread_info(idle
)->preempt_count
= (idle
->lock_depth
>= 0);
7006 task_thread_info(idle
)->preempt_count
= 0;
7009 * The idle tasks have their own, simple scheduling class:
7011 idle
->sched_class
= &idle_sched_class
;
7012 ftrace_graph_init_task(idle
);
7016 * In a system that switches off the HZ timer nohz_cpu_mask
7017 * indicates which cpus entered this state. This is used
7018 * in the rcu update to wait only for active cpus. For system
7019 * which do not switch off the HZ timer nohz_cpu_mask should
7020 * always be CPU_BITS_NONE.
7022 cpumask_var_t nohz_cpu_mask
;
7025 * Increase the granularity value when there are more CPUs,
7026 * because with more CPUs the 'effective latency' as visible
7027 * to users decreases. But the relationship is not linear,
7028 * so pick a second-best guess by going with the log2 of the
7031 * This idea comes from the SD scheduler of Con Kolivas:
7033 static void update_sysctl(void)
7035 unsigned int cpus
= min(num_online_cpus(), 8U);
7036 unsigned int factor
;
7038 switch (sysctl_sched_tunable_scaling
) {
7039 case SCHED_TUNABLESCALING_NONE
:
7042 case SCHED_TUNABLESCALING_LINEAR
:
7045 case SCHED_TUNABLESCALING_LOG
:
7047 factor
= 1 + ilog2(cpus
);
7051 #define SET_SYSCTL(name) \
7052 (sysctl_##name = (factor) * normalized_sysctl_##name)
7053 SET_SYSCTL(sched_min_granularity
);
7054 SET_SYSCTL(sched_latency
);
7055 SET_SYSCTL(sched_wakeup_granularity
);
7056 SET_SYSCTL(sched_shares_ratelimit
);
7060 static inline void sched_init_granularity(void)
7067 * This is how migration works:
7069 * 1) we queue a struct migration_req structure in the source CPU's
7070 * runqueue and wake up that CPU's migration thread.
7071 * 2) we down() the locked semaphore => thread blocks.
7072 * 3) migration thread wakes up (implicitly it forces the migrated
7073 * thread off the CPU)
7074 * 4) it gets the migration request and checks whether the migrated
7075 * task is still in the wrong runqueue.
7076 * 5) if it's in the wrong runqueue then the migration thread removes
7077 * it and puts it into the right queue.
7078 * 6) migration thread up()s the semaphore.
7079 * 7) we wake up and the migration is done.
7083 * Change a given task's CPU affinity. Migrate the thread to a
7084 * proper CPU and schedule it away if the CPU it's executing on
7085 * is removed from the allowed bitmask.
7087 * NOTE: the caller must have a valid reference to the task, the
7088 * task must not exit() & deallocate itself prematurely. The
7089 * call is not atomic; no spinlocks may be held.
7091 int set_cpus_allowed_ptr(struct task_struct
*p
, const struct cpumask
*new_mask
)
7093 struct migration_req req
;
7094 unsigned long flags
;
7098 rq
= task_rq_lock(p
, &flags
);
7099 if (!cpumask_intersects(new_mask
, cpu_active_mask
)) {
7104 if (unlikely((p
->flags
& PF_THREAD_BOUND
) && p
!= current
&&
7105 !cpumask_equal(&p
->cpus_allowed
, new_mask
))) {
7110 if (p
->sched_class
->set_cpus_allowed
)
7111 p
->sched_class
->set_cpus_allowed(p
, new_mask
);
7113 cpumask_copy(&p
->cpus_allowed
, new_mask
);
7114 p
->rt
.nr_cpus_allowed
= cpumask_weight(new_mask
);
7117 /* Can the task run on the task's current CPU? If so, we're done */
7118 if (cpumask_test_cpu(task_cpu(p
), new_mask
))
7121 if (migrate_task(p
, cpumask_any_and(cpu_active_mask
, new_mask
), &req
)) {
7122 /* Need help from migration thread: drop lock and wait. */
7123 struct task_struct
*mt
= rq
->migration_thread
;
7125 get_task_struct(mt
);
7126 task_rq_unlock(rq
, &flags
);
7127 wake_up_process(rq
->migration_thread
);
7128 put_task_struct(mt
);
7129 wait_for_completion(&req
.done
);
7130 tlb_migrate_finish(p
->mm
);
7134 task_rq_unlock(rq
, &flags
);
7138 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr
);
7141 * Move (not current) task off this cpu, onto dest cpu. We're doing
7142 * this because either it can't run here any more (set_cpus_allowed()
7143 * away from this CPU, or CPU going down), or because we're
7144 * attempting to rebalance this task on exec (sched_exec).
7146 * So we race with normal scheduler movements, but that's OK, as long
7147 * as the task is no longer on this CPU.
7149 * Returns non-zero if task was successfully migrated.
7151 static int __migrate_task(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
7153 struct rq
*rq_dest
, *rq_src
;
7156 if (unlikely(!cpu_active(dest_cpu
)))
7159 rq_src
= cpu_rq(src_cpu
);
7160 rq_dest
= cpu_rq(dest_cpu
);
7162 double_rq_lock(rq_src
, rq_dest
);
7163 /* Already moved. */
7164 if (task_cpu(p
) != src_cpu
)
7166 /* Affinity changed (again). */
7167 if (!cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
))
7170 on_rq
= p
->se
.on_rq
;
7172 deactivate_task(rq_src
, p
, 0);
7174 set_task_cpu(p
, dest_cpu
);
7176 activate_task(rq_dest
, p
, 0);
7177 check_preempt_curr(rq_dest
, p
, 0);
7182 double_rq_unlock(rq_src
, rq_dest
);
7186 #define RCU_MIGRATION_IDLE 0
7187 #define RCU_MIGRATION_NEED_QS 1
7188 #define RCU_MIGRATION_GOT_QS 2
7189 #define RCU_MIGRATION_MUST_SYNC 3
7192 * migration_thread - this is a highprio system thread that performs
7193 * thread migration by bumping thread off CPU then 'pushing' onto
7196 static int migration_thread(void *data
)
7199 int cpu
= (long)data
;
7203 BUG_ON(rq
->migration_thread
!= current
);
7205 set_current_state(TASK_INTERRUPTIBLE
);
7206 while (!kthread_should_stop()) {
7207 struct migration_req
*req
;
7208 struct list_head
*head
;
7210 spin_lock_irq(&rq
->lock
);
7212 if (cpu_is_offline(cpu
)) {
7213 spin_unlock_irq(&rq
->lock
);
7217 if (rq
->active_balance
) {
7218 active_load_balance(rq
, cpu
);
7219 rq
->active_balance
= 0;
7222 head
= &rq
->migration_queue
;
7224 if (list_empty(head
)) {
7225 spin_unlock_irq(&rq
->lock
);
7227 set_current_state(TASK_INTERRUPTIBLE
);
7230 req
= list_entry(head
->next
, struct migration_req
, list
);
7231 list_del_init(head
->next
);
7233 if (req
->task
!= NULL
) {
7234 spin_unlock(&rq
->lock
);
7235 __migrate_task(req
->task
, cpu
, req
->dest_cpu
);
7236 } else if (likely(cpu
== (badcpu
= smp_processor_id()))) {
7237 req
->dest_cpu
= RCU_MIGRATION_GOT_QS
;
7238 spin_unlock(&rq
->lock
);
7240 req
->dest_cpu
= RCU_MIGRATION_MUST_SYNC
;
7241 spin_unlock(&rq
->lock
);
7242 WARN_ONCE(1, "migration_thread() on CPU %d, expected %d\n", badcpu
, cpu
);
7246 complete(&req
->done
);
7248 __set_current_state(TASK_RUNNING
);
7253 #ifdef CONFIG_HOTPLUG_CPU
7255 static int __migrate_task_irq(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
7259 local_irq_disable();
7260 ret
= __migrate_task(p
, src_cpu
, dest_cpu
);
7266 * Figure out where task on dead CPU should go, use force if necessary.
7268 static void move_task_off_dead_cpu(int dead_cpu
, struct task_struct
*p
)
7271 const struct cpumask
*nodemask
= cpumask_of_node(cpu_to_node(dead_cpu
));
7274 /* Look for allowed, online CPU in same node. */
7275 for_each_cpu_and(dest_cpu
, nodemask
, cpu_active_mask
)
7276 if (cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
))
7279 /* Any allowed, online CPU? */
7280 dest_cpu
= cpumask_any_and(&p
->cpus_allowed
, cpu_active_mask
);
7281 if (dest_cpu
< nr_cpu_ids
)
7284 /* No more Mr. Nice Guy. */
7285 if (dest_cpu
>= nr_cpu_ids
) {
7286 cpuset_cpus_allowed_locked(p
, &p
->cpus_allowed
);
7287 dest_cpu
= cpumask_any_and(cpu_active_mask
, &p
->cpus_allowed
);
7290 * Don't tell them about moving exiting tasks or
7291 * kernel threads (both mm NULL), since they never
7294 if (p
->mm
&& printk_ratelimit()) {
7295 printk(KERN_INFO
"process %d (%s) no "
7296 "longer affine to cpu%d\n",
7297 task_pid_nr(p
), p
->comm
, dead_cpu
);
7302 /* It can have affinity changed while we were choosing. */
7303 if (unlikely(!__migrate_task_irq(p
, dead_cpu
, dest_cpu
)))
7308 * While a dead CPU has no uninterruptible tasks queued at this point,
7309 * it might still have a nonzero ->nr_uninterruptible counter, because
7310 * for performance reasons the counter is not stricly tracking tasks to
7311 * their home CPUs. So we just add the counter to another CPU's counter,
7312 * to keep the global sum constant after CPU-down:
7314 static void migrate_nr_uninterruptible(struct rq
*rq_src
)
7316 struct rq
*rq_dest
= cpu_rq(cpumask_any(cpu_active_mask
));
7317 unsigned long flags
;
7319 local_irq_save(flags
);
7320 double_rq_lock(rq_src
, rq_dest
);
7321 rq_dest
->nr_uninterruptible
+= rq_src
->nr_uninterruptible
;
7322 rq_src
->nr_uninterruptible
= 0;
7323 double_rq_unlock(rq_src
, rq_dest
);
7324 local_irq_restore(flags
);
7327 /* Run through task list and migrate tasks from the dead cpu. */
7328 static void migrate_live_tasks(int src_cpu
)
7330 struct task_struct
*p
, *t
;
7332 read_lock(&tasklist_lock
);
7334 do_each_thread(t
, p
) {
7338 if (task_cpu(p
) == src_cpu
)
7339 move_task_off_dead_cpu(src_cpu
, p
);
7340 } while_each_thread(t
, p
);
7342 read_unlock(&tasklist_lock
);
7346 * Schedules idle task to be the next runnable task on current CPU.
7347 * It does so by boosting its priority to highest possible.
7348 * Used by CPU offline code.
7350 void sched_idle_next(void)
7352 int this_cpu
= smp_processor_id();
7353 struct rq
*rq
= cpu_rq(this_cpu
);
7354 struct task_struct
*p
= rq
->idle
;
7355 unsigned long flags
;
7357 /* cpu has to be offline */
7358 BUG_ON(cpu_online(this_cpu
));
7361 * Strictly not necessary since rest of the CPUs are stopped by now
7362 * and interrupts disabled on the current cpu.
7364 spin_lock_irqsave(&rq
->lock
, flags
);
7366 __setscheduler(rq
, p
, SCHED_FIFO
, MAX_RT_PRIO
-1);
7368 update_rq_clock(rq
);
7369 activate_task(rq
, p
, 0);
7371 spin_unlock_irqrestore(&rq
->lock
, flags
);
7375 * Ensures that the idle task is using init_mm right before its cpu goes
7378 void idle_task_exit(void)
7380 struct mm_struct
*mm
= current
->active_mm
;
7382 BUG_ON(cpu_online(smp_processor_id()));
7385 switch_mm(mm
, &init_mm
, current
);
7389 /* called under rq->lock with disabled interrupts */
7390 static void migrate_dead(unsigned int dead_cpu
, struct task_struct
*p
)
7392 struct rq
*rq
= cpu_rq(dead_cpu
);
7394 /* Must be exiting, otherwise would be on tasklist. */
7395 BUG_ON(!p
->exit_state
);
7397 /* Cannot have done final schedule yet: would have vanished. */
7398 BUG_ON(p
->state
== TASK_DEAD
);
7403 * Drop lock around migration; if someone else moves it,
7404 * that's OK. No task can be added to this CPU, so iteration is
7407 spin_unlock_irq(&rq
->lock
);
7408 move_task_off_dead_cpu(dead_cpu
, p
);
7409 spin_lock_irq(&rq
->lock
);
7414 /* release_task() removes task from tasklist, so we won't find dead tasks. */
7415 static void migrate_dead_tasks(unsigned int dead_cpu
)
7417 struct rq
*rq
= cpu_rq(dead_cpu
);
7418 struct task_struct
*next
;
7421 if (!rq
->nr_running
)
7423 update_rq_clock(rq
);
7424 next
= pick_next_task(rq
);
7427 next
->sched_class
->put_prev_task(rq
, next
);
7428 migrate_dead(dead_cpu
, next
);
7434 * remove the tasks which were accounted by rq from calc_load_tasks.
7436 static void calc_global_load_remove(struct rq
*rq
)
7438 atomic_long_sub(rq
->calc_load_active
, &calc_load_tasks
);
7439 rq
->calc_load_active
= 0;
7441 #endif /* CONFIG_HOTPLUG_CPU */
7443 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
7445 static struct ctl_table sd_ctl_dir
[] = {
7447 .procname
= "sched_domain",
7453 static struct ctl_table sd_ctl_root
[] = {
7455 .ctl_name
= CTL_KERN
,
7456 .procname
= "kernel",
7458 .child
= sd_ctl_dir
,
7463 static struct ctl_table
*sd_alloc_ctl_entry(int n
)
7465 struct ctl_table
*entry
=
7466 kcalloc(n
, sizeof(struct ctl_table
), GFP_KERNEL
);
7471 static void sd_free_ctl_entry(struct ctl_table
**tablep
)
7473 struct ctl_table
*entry
;
7476 * In the intermediate directories, both the child directory and
7477 * procname are dynamically allocated and could fail but the mode
7478 * will always be set. In the lowest directory the names are
7479 * static strings and all have proc handlers.
7481 for (entry
= *tablep
; entry
->mode
; entry
++) {
7483 sd_free_ctl_entry(&entry
->child
);
7484 if (entry
->proc_handler
== NULL
)
7485 kfree(entry
->procname
);
7493 set_table_entry(struct ctl_table
*entry
,
7494 const char *procname
, void *data
, int maxlen
,
7495 mode_t mode
, proc_handler
*proc_handler
)
7497 entry
->procname
= procname
;
7499 entry
->maxlen
= maxlen
;
7501 entry
->proc_handler
= proc_handler
;
7504 static struct ctl_table
*
7505 sd_alloc_ctl_domain_table(struct sched_domain
*sd
)
7507 struct ctl_table
*table
= sd_alloc_ctl_entry(13);
7512 set_table_entry(&table
[0], "min_interval", &sd
->min_interval
,
7513 sizeof(long), 0644, proc_doulongvec_minmax
);
7514 set_table_entry(&table
[1], "max_interval", &sd
->max_interval
,
7515 sizeof(long), 0644, proc_doulongvec_minmax
);
7516 set_table_entry(&table
[2], "busy_idx", &sd
->busy_idx
,
7517 sizeof(int), 0644, proc_dointvec_minmax
);
7518 set_table_entry(&table
[3], "idle_idx", &sd
->idle_idx
,
7519 sizeof(int), 0644, proc_dointvec_minmax
);
7520 set_table_entry(&table
[4], "newidle_idx", &sd
->newidle_idx
,
7521 sizeof(int), 0644, proc_dointvec_minmax
);
7522 set_table_entry(&table
[5], "wake_idx", &sd
->wake_idx
,
7523 sizeof(int), 0644, proc_dointvec_minmax
);
7524 set_table_entry(&table
[6], "forkexec_idx", &sd
->forkexec_idx
,
7525 sizeof(int), 0644, proc_dointvec_minmax
);
7526 set_table_entry(&table
[7], "busy_factor", &sd
->busy_factor
,
7527 sizeof(int), 0644, proc_dointvec_minmax
);
7528 set_table_entry(&table
[8], "imbalance_pct", &sd
->imbalance_pct
,
7529 sizeof(int), 0644, proc_dointvec_minmax
);
7530 set_table_entry(&table
[9], "cache_nice_tries",
7531 &sd
->cache_nice_tries
,
7532 sizeof(int), 0644, proc_dointvec_minmax
);
7533 set_table_entry(&table
[10], "flags", &sd
->flags
,
7534 sizeof(int), 0644, proc_dointvec_minmax
);
7535 set_table_entry(&table
[11], "name", sd
->name
,
7536 CORENAME_MAX_SIZE
, 0444, proc_dostring
);
7537 /* &table[12] is terminator */
7542 static ctl_table
*sd_alloc_ctl_cpu_table(int cpu
)
7544 struct ctl_table
*entry
, *table
;
7545 struct sched_domain
*sd
;
7546 int domain_num
= 0, i
;
7549 for_each_domain(cpu
, sd
)
7551 entry
= table
= sd_alloc_ctl_entry(domain_num
+ 1);
7556 for_each_domain(cpu
, sd
) {
7557 snprintf(buf
, 32, "domain%d", i
);
7558 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
7560 entry
->child
= sd_alloc_ctl_domain_table(sd
);
7567 static struct ctl_table_header
*sd_sysctl_header
;
7568 static void register_sched_domain_sysctl(void)
7570 int i
, cpu_num
= num_possible_cpus();
7571 struct ctl_table
*entry
= sd_alloc_ctl_entry(cpu_num
+ 1);
7574 WARN_ON(sd_ctl_dir
[0].child
);
7575 sd_ctl_dir
[0].child
= entry
;
7580 for_each_possible_cpu(i
) {
7581 snprintf(buf
, 32, "cpu%d", i
);
7582 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
7584 entry
->child
= sd_alloc_ctl_cpu_table(i
);
7588 WARN_ON(sd_sysctl_header
);
7589 sd_sysctl_header
= register_sysctl_table(sd_ctl_root
);
7592 /* may be called multiple times per register */
7593 static void unregister_sched_domain_sysctl(void)
7595 if (sd_sysctl_header
)
7596 unregister_sysctl_table(sd_sysctl_header
);
7597 sd_sysctl_header
= NULL
;
7598 if (sd_ctl_dir
[0].child
)
7599 sd_free_ctl_entry(&sd_ctl_dir
[0].child
);
7602 static void register_sched_domain_sysctl(void)
7605 static void unregister_sched_domain_sysctl(void)
7610 static void set_rq_online(struct rq
*rq
)
7613 const struct sched_class
*class;
7615 cpumask_set_cpu(rq
->cpu
, rq
->rd
->online
);
7618 for_each_class(class) {
7619 if (class->rq_online
)
7620 class->rq_online(rq
);
7625 static void set_rq_offline(struct rq
*rq
)
7628 const struct sched_class
*class;
7630 for_each_class(class) {
7631 if (class->rq_offline
)
7632 class->rq_offline(rq
);
7635 cpumask_clear_cpu(rq
->cpu
, rq
->rd
->online
);
7641 * migration_call - callback that gets triggered when a CPU is added.
7642 * Here we can start up the necessary migration thread for the new CPU.
7644 static int __cpuinit
7645 migration_call(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
7647 struct task_struct
*p
;
7648 int cpu
= (long)hcpu
;
7649 unsigned long flags
;
7654 case CPU_UP_PREPARE
:
7655 case CPU_UP_PREPARE_FROZEN
:
7656 p
= kthread_create(migration_thread
, hcpu
, "migration/%d", cpu
);
7659 kthread_bind(p
, cpu
);
7660 /* Must be high prio: stop_machine expects to yield to it. */
7661 rq
= task_rq_lock(p
, &flags
);
7662 __setscheduler(rq
, p
, SCHED_FIFO
, MAX_RT_PRIO
-1);
7663 task_rq_unlock(rq
, &flags
);
7665 cpu_rq(cpu
)->migration_thread
= p
;
7666 rq
->calc_load_update
= calc_load_update
;
7670 case CPU_ONLINE_FROZEN
:
7671 /* Strictly unnecessary, as first user will wake it. */
7672 wake_up_process(cpu_rq(cpu
)->migration_thread
);
7674 /* Update our root-domain */
7676 spin_lock_irqsave(&rq
->lock
, flags
);
7678 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
7682 spin_unlock_irqrestore(&rq
->lock
, flags
);
7685 #ifdef CONFIG_HOTPLUG_CPU
7686 case CPU_UP_CANCELED
:
7687 case CPU_UP_CANCELED_FROZEN
:
7688 if (!cpu_rq(cpu
)->migration_thread
)
7690 /* Unbind it from offline cpu so it can run. Fall thru. */
7691 kthread_bind(cpu_rq(cpu
)->migration_thread
,
7692 cpumask_any(cpu_online_mask
));
7693 kthread_stop(cpu_rq(cpu
)->migration_thread
);
7694 put_task_struct(cpu_rq(cpu
)->migration_thread
);
7695 cpu_rq(cpu
)->migration_thread
= NULL
;
7699 case CPU_DEAD_FROZEN
:
7700 cpuset_lock(); /* around calls to cpuset_cpus_allowed_lock() */
7701 migrate_live_tasks(cpu
);
7703 kthread_stop(rq
->migration_thread
);
7704 put_task_struct(rq
->migration_thread
);
7705 rq
->migration_thread
= NULL
;
7706 /* Idle task back to normal (off runqueue, low prio) */
7707 spin_lock_irq(&rq
->lock
);
7708 update_rq_clock(rq
);
7709 deactivate_task(rq
, rq
->idle
, 0);
7710 __setscheduler(rq
, rq
->idle
, SCHED_NORMAL
, 0);
7711 rq
->idle
->sched_class
= &idle_sched_class
;
7712 migrate_dead_tasks(cpu
);
7713 spin_unlock_irq(&rq
->lock
);
7715 migrate_nr_uninterruptible(rq
);
7716 BUG_ON(rq
->nr_running
!= 0);
7717 calc_global_load_remove(rq
);
7719 * No need to migrate the tasks: it was best-effort if
7720 * they didn't take sched_hotcpu_mutex. Just wake up
7723 spin_lock_irq(&rq
->lock
);
7724 while (!list_empty(&rq
->migration_queue
)) {
7725 struct migration_req
*req
;
7727 req
= list_entry(rq
->migration_queue
.next
,
7728 struct migration_req
, list
);
7729 list_del_init(&req
->list
);
7730 spin_unlock_irq(&rq
->lock
);
7731 complete(&req
->done
);
7732 spin_lock_irq(&rq
->lock
);
7734 spin_unlock_irq(&rq
->lock
);
7738 case CPU_DYING_FROZEN
:
7739 /* Update our root-domain */
7741 spin_lock_irqsave(&rq
->lock
, flags
);
7743 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
7746 spin_unlock_irqrestore(&rq
->lock
, flags
);
7754 * Register at high priority so that task migration (migrate_all_tasks)
7755 * happens before everything else. This has to be lower priority than
7756 * the notifier in the perf_event subsystem, though.
7758 static struct notifier_block __cpuinitdata migration_notifier
= {
7759 .notifier_call
= migration_call
,
7763 static int __init
migration_init(void)
7765 void *cpu
= (void *)(long)smp_processor_id();
7768 /* Start one for the boot CPU: */
7769 err
= migration_call(&migration_notifier
, CPU_UP_PREPARE
, cpu
);
7770 BUG_ON(err
== NOTIFY_BAD
);
7771 migration_call(&migration_notifier
, CPU_ONLINE
, cpu
);
7772 register_cpu_notifier(&migration_notifier
);
7776 early_initcall(migration_init
);
7781 #ifdef CONFIG_SCHED_DEBUG
7783 static __read_mostly
int sched_domain_debug_enabled
;
7785 static int __init
sched_domain_debug_setup(char *str
)
7787 sched_domain_debug_enabled
= 1;
7791 early_param("sched_debug", sched_domain_debug_setup
);
7793 static int sched_domain_debug_one(struct sched_domain
*sd
, int cpu
, int level
,
7794 struct cpumask
*groupmask
)
7796 struct sched_group
*group
= sd
->groups
;
7799 cpulist_scnprintf(str
, sizeof(str
), sched_domain_span(sd
));
7800 cpumask_clear(groupmask
);
7802 printk(KERN_DEBUG
"%*s domain %d: ", level
, "", level
);
7804 if (!(sd
->flags
& SD_LOAD_BALANCE
)) {
7805 printk("does not load-balance\n");
7807 printk(KERN_ERR
"ERROR: !SD_LOAD_BALANCE domain"
7812 printk(KERN_CONT
"span %s level %s\n", str
, sd
->name
);
7814 if (!cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
7815 printk(KERN_ERR
"ERROR: domain->span does not contain "
7818 if (!cpumask_test_cpu(cpu
, sched_group_cpus(group
))) {
7819 printk(KERN_ERR
"ERROR: domain->groups does not contain"
7823 printk(KERN_DEBUG
"%*s groups:", level
+ 1, "");
7827 printk(KERN_ERR
"ERROR: group is NULL\n");
7831 if (!group
->cpu_power
) {
7832 printk(KERN_CONT
"\n");
7833 printk(KERN_ERR
"ERROR: domain->cpu_power not "
7838 if (!cpumask_weight(sched_group_cpus(group
))) {
7839 printk(KERN_CONT
"\n");
7840 printk(KERN_ERR
"ERROR: empty group\n");
7844 if (cpumask_intersects(groupmask
, sched_group_cpus(group
))) {
7845 printk(KERN_CONT
"\n");
7846 printk(KERN_ERR
"ERROR: repeated CPUs\n");
7850 cpumask_or(groupmask
, groupmask
, sched_group_cpus(group
));
7852 cpulist_scnprintf(str
, sizeof(str
), sched_group_cpus(group
));
7854 printk(KERN_CONT
" %s", str
);
7855 if (group
->cpu_power
!= SCHED_LOAD_SCALE
) {
7856 printk(KERN_CONT
" (cpu_power = %d)",
7860 group
= group
->next
;
7861 } while (group
!= sd
->groups
);
7862 printk(KERN_CONT
"\n");
7864 if (!cpumask_equal(sched_domain_span(sd
), groupmask
))
7865 printk(KERN_ERR
"ERROR: groups don't span domain->span\n");
7868 !cpumask_subset(groupmask
, sched_domain_span(sd
->parent
)))
7869 printk(KERN_ERR
"ERROR: parent span is not a superset "
7870 "of domain->span\n");
7874 static void sched_domain_debug(struct sched_domain
*sd
, int cpu
)
7876 cpumask_var_t groupmask
;
7879 if (!sched_domain_debug_enabled
)
7883 printk(KERN_DEBUG
"CPU%d attaching NULL sched-domain.\n", cpu
);
7887 printk(KERN_DEBUG
"CPU%d attaching sched-domain:\n", cpu
);
7889 if (!alloc_cpumask_var(&groupmask
, GFP_KERNEL
)) {
7890 printk(KERN_DEBUG
"Cannot load-balance (out of memory)\n");
7895 if (sched_domain_debug_one(sd
, cpu
, level
, groupmask
))
7902 free_cpumask_var(groupmask
);
7904 #else /* !CONFIG_SCHED_DEBUG */
7905 # define sched_domain_debug(sd, cpu) do { } while (0)
7906 #endif /* CONFIG_SCHED_DEBUG */
7908 static int sd_degenerate(struct sched_domain
*sd
)
7910 if (cpumask_weight(sched_domain_span(sd
)) == 1)
7913 /* Following flags need at least 2 groups */
7914 if (sd
->flags
& (SD_LOAD_BALANCE
|
7915 SD_BALANCE_NEWIDLE
|
7919 SD_SHARE_PKG_RESOURCES
)) {
7920 if (sd
->groups
!= sd
->groups
->next
)
7924 /* Following flags don't use groups */
7925 if (sd
->flags
& (SD_WAKE_AFFINE
))
7932 sd_parent_degenerate(struct sched_domain
*sd
, struct sched_domain
*parent
)
7934 unsigned long cflags
= sd
->flags
, pflags
= parent
->flags
;
7936 if (sd_degenerate(parent
))
7939 if (!cpumask_equal(sched_domain_span(sd
), sched_domain_span(parent
)))
7942 /* Flags needing groups don't count if only 1 group in parent */
7943 if (parent
->groups
== parent
->groups
->next
) {
7944 pflags
&= ~(SD_LOAD_BALANCE
|
7945 SD_BALANCE_NEWIDLE
|
7949 SD_SHARE_PKG_RESOURCES
);
7950 if (nr_node_ids
== 1)
7951 pflags
&= ~SD_SERIALIZE
;
7953 if (~cflags
& pflags
)
7959 static void free_rootdomain(struct root_domain
*rd
)
7961 synchronize_sched();
7963 cpupri_cleanup(&rd
->cpupri
);
7965 free_cpumask_var(rd
->rto_mask
);
7966 free_cpumask_var(rd
->online
);
7967 free_cpumask_var(rd
->span
);
7971 static void rq_attach_root(struct rq
*rq
, struct root_domain
*rd
)
7973 struct root_domain
*old_rd
= NULL
;
7974 unsigned long flags
;
7976 spin_lock_irqsave(&rq
->lock
, flags
);
7981 if (cpumask_test_cpu(rq
->cpu
, old_rd
->online
))
7984 cpumask_clear_cpu(rq
->cpu
, old_rd
->span
);
7987 * If we dont want to free the old_rt yet then
7988 * set old_rd to NULL to skip the freeing later
7991 if (!atomic_dec_and_test(&old_rd
->refcount
))
7995 atomic_inc(&rd
->refcount
);
7998 cpumask_set_cpu(rq
->cpu
, rd
->span
);
7999 if (cpumask_test_cpu(rq
->cpu
, cpu_active_mask
))
8002 spin_unlock_irqrestore(&rq
->lock
, flags
);
8005 free_rootdomain(old_rd
);
8008 static int init_rootdomain(struct root_domain
*rd
, bool bootmem
)
8010 gfp_t gfp
= GFP_KERNEL
;
8012 memset(rd
, 0, sizeof(*rd
));
8017 if (!alloc_cpumask_var(&rd
->span
, gfp
))
8019 if (!alloc_cpumask_var(&rd
->online
, gfp
))
8021 if (!alloc_cpumask_var(&rd
->rto_mask
, gfp
))
8024 if (cpupri_init(&rd
->cpupri
, bootmem
) != 0)
8029 free_cpumask_var(rd
->rto_mask
);
8031 free_cpumask_var(rd
->online
);
8033 free_cpumask_var(rd
->span
);
8038 static void init_defrootdomain(void)
8040 init_rootdomain(&def_root_domain
, true);
8042 atomic_set(&def_root_domain
.refcount
, 1);
8045 static struct root_domain
*alloc_rootdomain(void)
8047 struct root_domain
*rd
;
8049 rd
= kmalloc(sizeof(*rd
), GFP_KERNEL
);
8053 if (init_rootdomain(rd
, false) != 0) {
8062 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
8063 * hold the hotplug lock.
8066 cpu_attach_domain(struct sched_domain
*sd
, struct root_domain
*rd
, int cpu
)
8068 struct rq
*rq
= cpu_rq(cpu
);
8069 struct sched_domain
*tmp
;
8071 /* Remove the sched domains which do not contribute to scheduling. */
8072 for (tmp
= sd
; tmp
; ) {
8073 struct sched_domain
*parent
= tmp
->parent
;
8077 if (sd_parent_degenerate(tmp
, parent
)) {
8078 tmp
->parent
= parent
->parent
;
8080 parent
->parent
->child
= tmp
;
8085 if (sd
&& sd_degenerate(sd
)) {
8091 sched_domain_debug(sd
, cpu
);
8093 rq_attach_root(rq
, rd
);
8094 rcu_assign_pointer(rq
->sd
, sd
);
8097 /* cpus with isolated domains */
8098 static cpumask_var_t cpu_isolated_map
;
8100 /* Setup the mask of cpus configured for isolated domains */
8101 static int __init
isolated_cpu_setup(char *str
)
8103 alloc_bootmem_cpumask_var(&cpu_isolated_map
);
8104 cpulist_parse(str
, cpu_isolated_map
);
8108 __setup("isolcpus=", isolated_cpu_setup
);
8111 * init_sched_build_groups takes the cpumask we wish to span, and a pointer
8112 * to a function which identifies what group(along with sched group) a CPU
8113 * belongs to. The return value of group_fn must be a >= 0 and < nr_cpu_ids
8114 * (due to the fact that we keep track of groups covered with a struct cpumask).
8116 * init_sched_build_groups will build a circular linked list of the groups
8117 * covered by the given span, and will set each group's ->cpumask correctly,
8118 * and ->cpu_power to 0.
8121 init_sched_build_groups(const struct cpumask
*span
,
8122 const struct cpumask
*cpu_map
,
8123 int (*group_fn
)(int cpu
, const struct cpumask
*cpu_map
,
8124 struct sched_group
**sg
,
8125 struct cpumask
*tmpmask
),
8126 struct cpumask
*covered
, struct cpumask
*tmpmask
)
8128 struct sched_group
*first
= NULL
, *last
= NULL
;
8131 cpumask_clear(covered
);
8133 for_each_cpu(i
, span
) {
8134 struct sched_group
*sg
;
8135 int group
= group_fn(i
, cpu_map
, &sg
, tmpmask
);
8138 if (cpumask_test_cpu(i
, covered
))
8141 cpumask_clear(sched_group_cpus(sg
));
8144 for_each_cpu(j
, span
) {
8145 if (group_fn(j
, cpu_map
, NULL
, tmpmask
) != group
)
8148 cpumask_set_cpu(j
, covered
);
8149 cpumask_set_cpu(j
, sched_group_cpus(sg
));
8160 #define SD_NODES_PER_DOMAIN 16
8165 * find_next_best_node - find the next node to include in a sched_domain
8166 * @node: node whose sched_domain we're building
8167 * @used_nodes: nodes already in the sched_domain
8169 * Find the next node to include in a given scheduling domain. Simply
8170 * finds the closest node not already in the @used_nodes map.
8172 * Should use nodemask_t.
8174 static int find_next_best_node(int node
, nodemask_t
*used_nodes
)
8176 int i
, n
, val
, min_val
, best_node
= 0;
8180 for (i
= 0; i
< nr_node_ids
; i
++) {
8181 /* Start at @node */
8182 n
= (node
+ i
) % nr_node_ids
;
8184 if (!nr_cpus_node(n
))
8187 /* Skip already used nodes */
8188 if (node_isset(n
, *used_nodes
))
8191 /* Simple min distance search */
8192 val
= node_distance(node
, n
);
8194 if (val
< min_val
) {
8200 node_set(best_node
, *used_nodes
);
8205 * sched_domain_node_span - get a cpumask for a node's sched_domain
8206 * @node: node whose cpumask we're constructing
8207 * @span: resulting cpumask
8209 * Given a node, construct a good cpumask for its sched_domain to span. It
8210 * should be one that prevents unnecessary balancing, but also spreads tasks
8213 static void sched_domain_node_span(int node
, struct cpumask
*span
)
8215 nodemask_t used_nodes
;
8218 cpumask_clear(span
);
8219 nodes_clear(used_nodes
);
8221 cpumask_or(span
, span
, cpumask_of_node(node
));
8222 node_set(node
, used_nodes
);
8224 for (i
= 1; i
< SD_NODES_PER_DOMAIN
; i
++) {
8225 int next_node
= find_next_best_node(node
, &used_nodes
);
8227 cpumask_or(span
, span
, cpumask_of_node(next_node
));
8230 #endif /* CONFIG_NUMA */
8232 int sched_smt_power_savings
= 0, sched_mc_power_savings
= 0;
8235 * The cpus mask in sched_group and sched_domain hangs off the end.
8237 * ( See the the comments in include/linux/sched.h:struct sched_group
8238 * and struct sched_domain. )
8240 struct static_sched_group
{
8241 struct sched_group sg
;
8242 DECLARE_BITMAP(cpus
, CONFIG_NR_CPUS
);
8245 struct static_sched_domain
{
8246 struct sched_domain sd
;
8247 DECLARE_BITMAP(span
, CONFIG_NR_CPUS
);
8253 cpumask_var_t domainspan
;
8254 cpumask_var_t covered
;
8255 cpumask_var_t notcovered
;
8257 cpumask_var_t nodemask
;
8258 cpumask_var_t this_sibling_map
;
8259 cpumask_var_t this_core_map
;
8260 cpumask_var_t send_covered
;
8261 cpumask_var_t tmpmask
;
8262 struct sched_group
**sched_group_nodes
;
8263 struct root_domain
*rd
;
8267 sa_sched_groups
= 0,
8272 sa_this_sibling_map
,
8274 sa_sched_group_nodes
,
8284 * SMT sched-domains:
8286 #ifdef CONFIG_SCHED_SMT
8287 static DEFINE_PER_CPU(struct static_sched_domain
, cpu_domains
);
8288 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_cpus
);
8291 cpu_to_cpu_group(int cpu
, const struct cpumask
*cpu_map
,
8292 struct sched_group
**sg
, struct cpumask
*unused
)
8295 *sg
= &per_cpu(sched_group_cpus
, cpu
).sg
;
8298 #endif /* CONFIG_SCHED_SMT */
8301 * multi-core sched-domains:
8303 #ifdef CONFIG_SCHED_MC
8304 static DEFINE_PER_CPU(struct static_sched_domain
, core_domains
);
8305 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_core
);
8306 #endif /* CONFIG_SCHED_MC */
8308 #if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT)
8310 cpu_to_core_group(int cpu
, const struct cpumask
*cpu_map
,
8311 struct sched_group
**sg
, struct cpumask
*mask
)
8315 cpumask_and(mask
, topology_thread_cpumask(cpu
), cpu_map
);
8316 group
= cpumask_first(mask
);
8318 *sg
= &per_cpu(sched_group_core
, group
).sg
;
8321 #elif defined(CONFIG_SCHED_MC)
8323 cpu_to_core_group(int cpu
, const struct cpumask
*cpu_map
,
8324 struct sched_group
**sg
, struct cpumask
*unused
)
8327 *sg
= &per_cpu(sched_group_core
, cpu
).sg
;
8332 static DEFINE_PER_CPU(struct static_sched_domain
, phys_domains
);
8333 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_phys
);
8336 cpu_to_phys_group(int cpu
, const struct cpumask
*cpu_map
,
8337 struct sched_group
**sg
, struct cpumask
*mask
)
8340 #ifdef CONFIG_SCHED_MC
8341 cpumask_and(mask
, cpu_coregroup_mask(cpu
), cpu_map
);
8342 group
= cpumask_first(mask
);
8343 #elif defined(CONFIG_SCHED_SMT)
8344 cpumask_and(mask
, topology_thread_cpumask(cpu
), cpu_map
);
8345 group
= cpumask_first(mask
);
8350 *sg
= &per_cpu(sched_group_phys
, group
).sg
;
8356 * The init_sched_build_groups can't handle what we want to do with node
8357 * groups, so roll our own. Now each node has its own list of groups which
8358 * gets dynamically allocated.
8360 static DEFINE_PER_CPU(struct static_sched_domain
, node_domains
);
8361 static struct sched_group
***sched_group_nodes_bycpu
;
8363 static DEFINE_PER_CPU(struct static_sched_domain
, allnodes_domains
);
8364 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_allnodes
);
8366 static int cpu_to_allnodes_group(int cpu
, const struct cpumask
*cpu_map
,
8367 struct sched_group
**sg
,
8368 struct cpumask
*nodemask
)
8372 cpumask_and(nodemask
, cpumask_of_node(cpu_to_node(cpu
)), cpu_map
);
8373 group
= cpumask_first(nodemask
);
8376 *sg
= &per_cpu(sched_group_allnodes
, group
).sg
;
8380 static void init_numa_sched_groups_power(struct sched_group
*group_head
)
8382 struct sched_group
*sg
= group_head
;
8388 for_each_cpu(j
, sched_group_cpus(sg
)) {
8389 struct sched_domain
*sd
;
8391 sd
= &per_cpu(phys_domains
, j
).sd
;
8392 if (j
!= group_first_cpu(sd
->groups
)) {
8394 * Only add "power" once for each
8400 sg
->cpu_power
+= sd
->groups
->cpu_power
;
8403 } while (sg
!= group_head
);
8406 static int build_numa_sched_groups(struct s_data
*d
,
8407 const struct cpumask
*cpu_map
, int num
)
8409 struct sched_domain
*sd
;
8410 struct sched_group
*sg
, *prev
;
8413 cpumask_clear(d
->covered
);
8414 cpumask_and(d
->nodemask
, cpumask_of_node(num
), cpu_map
);
8415 if (cpumask_empty(d
->nodemask
)) {
8416 d
->sched_group_nodes
[num
] = NULL
;
8420 sched_domain_node_span(num
, d
->domainspan
);
8421 cpumask_and(d
->domainspan
, d
->domainspan
, cpu_map
);
8423 sg
= kmalloc_node(sizeof(struct sched_group
) + cpumask_size(),
8426 printk(KERN_WARNING
"Can not alloc domain group for node %d\n",
8430 d
->sched_group_nodes
[num
] = sg
;
8432 for_each_cpu(j
, d
->nodemask
) {
8433 sd
= &per_cpu(node_domains
, j
).sd
;
8438 cpumask_copy(sched_group_cpus(sg
), d
->nodemask
);
8440 cpumask_or(d
->covered
, d
->covered
, d
->nodemask
);
8443 for (j
= 0; j
< nr_node_ids
; j
++) {
8444 n
= (num
+ j
) % nr_node_ids
;
8445 cpumask_complement(d
->notcovered
, d
->covered
);
8446 cpumask_and(d
->tmpmask
, d
->notcovered
, cpu_map
);
8447 cpumask_and(d
->tmpmask
, d
->tmpmask
, d
->domainspan
);
8448 if (cpumask_empty(d
->tmpmask
))
8450 cpumask_and(d
->tmpmask
, d
->tmpmask
, cpumask_of_node(n
));
8451 if (cpumask_empty(d
->tmpmask
))
8453 sg
= kmalloc_node(sizeof(struct sched_group
) + cpumask_size(),
8457 "Can not alloc domain group for node %d\n", j
);
8461 cpumask_copy(sched_group_cpus(sg
), d
->tmpmask
);
8462 sg
->next
= prev
->next
;
8463 cpumask_or(d
->covered
, d
->covered
, d
->tmpmask
);
8470 #endif /* CONFIG_NUMA */
8473 /* Free memory allocated for various sched_group structures */
8474 static void free_sched_groups(const struct cpumask
*cpu_map
,
8475 struct cpumask
*nodemask
)
8479 for_each_cpu(cpu
, cpu_map
) {
8480 struct sched_group
**sched_group_nodes
8481 = sched_group_nodes_bycpu
[cpu
];
8483 if (!sched_group_nodes
)
8486 for (i
= 0; i
< nr_node_ids
; i
++) {
8487 struct sched_group
*oldsg
, *sg
= sched_group_nodes
[i
];
8489 cpumask_and(nodemask
, cpumask_of_node(i
), cpu_map
);
8490 if (cpumask_empty(nodemask
))
8500 if (oldsg
!= sched_group_nodes
[i
])
8503 kfree(sched_group_nodes
);
8504 sched_group_nodes_bycpu
[cpu
] = NULL
;
8507 #else /* !CONFIG_NUMA */
8508 static void free_sched_groups(const struct cpumask
*cpu_map
,
8509 struct cpumask
*nodemask
)
8512 #endif /* CONFIG_NUMA */
8515 * Initialize sched groups cpu_power.
8517 * cpu_power indicates the capacity of sched group, which is used while
8518 * distributing the load between different sched groups in a sched domain.
8519 * Typically cpu_power for all the groups in a sched domain will be same unless
8520 * there are asymmetries in the topology. If there are asymmetries, group
8521 * having more cpu_power will pickup more load compared to the group having
8524 static void init_sched_groups_power(int cpu
, struct sched_domain
*sd
)
8526 struct sched_domain
*child
;
8527 struct sched_group
*group
;
8531 WARN_ON(!sd
|| !sd
->groups
);
8533 if (cpu
!= group_first_cpu(sd
->groups
))
8538 sd
->groups
->cpu_power
= 0;
8541 power
= SCHED_LOAD_SCALE
;
8542 weight
= cpumask_weight(sched_domain_span(sd
));
8544 * SMT siblings share the power of a single core.
8545 * Usually multiple threads get a better yield out of
8546 * that one core than a single thread would have,
8547 * reflect that in sd->smt_gain.
8549 if ((sd
->flags
& SD_SHARE_CPUPOWER
) && weight
> 1) {
8550 power
*= sd
->smt_gain
;
8552 power
>>= SCHED_LOAD_SHIFT
;
8554 sd
->groups
->cpu_power
+= power
;
8559 * Add cpu_power of each child group to this groups cpu_power.
8561 group
= child
->groups
;
8563 sd
->groups
->cpu_power
+= group
->cpu_power
;
8564 group
= group
->next
;
8565 } while (group
!= child
->groups
);
8569 * Initializers for schedule domains
8570 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
8573 #ifdef CONFIG_SCHED_DEBUG
8574 # define SD_INIT_NAME(sd, type) sd->name = #type
8576 # define SD_INIT_NAME(sd, type) do { } while (0)
8579 #define SD_INIT(sd, type) sd_init_##type(sd)
8581 #define SD_INIT_FUNC(type) \
8582 static noinline void sd_init_##type(struct sched_domain *sd) \
8584 memset(sd, 0, sizeof(*sd)); \
8585 *sd = SD_##type##_INIT; \
8586 sd->level = SD_LV_##type; \
8587 SD_INIT_NAME(sd, type); \
8592 SD_INIT_FUNC(ALLNODES
)
8595 #ifdef CONFIG_SCHED_SMT
8596 SD_INIT_FUNC(SIBLING
)
8598 #ifdef CONFIG_SCHED_MC
8602 static int default_relax_domain_level
= -1;
8604 static int __init
setup_relax_domain_level(char *str
)
8608 val
= simple_strtoul(str
, NULL
, 0);
8609 if (val
< SD_LV_MAX
)
8610 default_relax_domain_level
= val
;
8614 __setup("relax_domain_level=", setup_relax_domain_level
);
8616 static void set_domain_attribute(struct sched_domain
*sd
,
8617 struct sched_domain_attr
*attr
)
8621 if (!attr
|| attr
->relax_domain_level
< 0) {
8622 if (default_relax_domain_level
< 0)
8625 request
= default_relax_domain_level
;
8627 request
= attr
->relax_domain_level
;
8628 if (request
< sd
->level
) {
8629 /* turn off idle balance on this domain */
8630 sd
->flags
&= ~(SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
8632 /* turn on idle balance on this domain */
8633 sd
->flags
|= (SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
8637 static void __free_domain_allocs(struct s_data
*d
, enum s_alloc what
,
8638 const struct cpumask
*cpu_map
)
8641 case sa_sched_groups
:
8642 free_sched_groups(cpu_map
, d
->tmpmask
); /* fall through */
8643 d
->sched_group_nodes
= NULL
;
8645 free_rootdomain(d
->rd
); /* fall through */
8647 free_cpumask_var(d
->tmpmask
); /* fall through */
8648 case sa_send_covered
:
8649 free_cpumask_var(d
->send_covered
); /* fall through */
8650 case sa_this_core_map
:
8651 free_cpumask_var(d
->this_core_map
); /* fall through */
8652 case sa_this_sibling_map
:
8653 free_cpumask_var(d
->this_sibling_map
); /* fall through */
8655 free_cpumask_var(d
->nodemask
); /* fall through */
8656 case sa_sched_group_nodes
:
8658 kfree(d
->sched_group_nodes
); /* fall through */
8660 free_cpumask_var(d
->notcovered
); /* fall through */
8662 free_cpumask_var(d
->covered
); /* fall through */
8664 free_cpumask_var(d
->domainspan
); /* fall through */
8671 static enum s_alloc
__visit_domain_allocation_hell(struct s_data
*d
,
8672 const struct cpumask
*cpu_map
)
8675 if (!alloc_cpumask_var(&d
->domainspan
, GFP_KERNEL
))
8677 if (!alloc_cpumask_var(&d
->covered
, GFP_KERNEL
))
8678 return sa_domainspan
;
8679 if (!alloc_cpumask_var(&d
->notcovered
, GFP_KERNEL
))
8681 /* Allocate the per-node list of sched groups */
8682 d
->sched_group_nodes
= kcalloc(nr_node_ids
,
8683 sizeof(struct sched_group
*), GFP_KERNEL
);
8684 if (!d
->sched_group_nodes
) {
8685 printk(KERN_WARNING
"Can not alloc sched group node list\n");
8686 return sa_notcovered
;
8688 sched_group_nodes_bycpu
[cpumask_first(cpu_map
)] = d
->sched_group_nodes
;
8690 if (!alloc_cpumask_var(&d
->nodemask
, GFP_KERNEL
))
8691 return sa_sched_group_nodes
;
8692 if (!alloc_cpumask_var(&d
->this_sibling_map
, GFP_KERNEL
))
8694 if (!alloc_cpumask_var(&d
->this_core_map
, GFP_KERNEL
))
8695 return sa_this_sibling_map
;
8696 if (!alloc_cpumask_var(&d
->send_covered
, GFP_KERNEL
))
8697 return sa_this_core_map
;
8698 if (!alloc_cpumask_var(&d
->tmpmask
, GFP_KERNEL
))
8699 return sa_send_covered
;
8700 d
->rd
= alloc_rootdomain();
8702 printk(KERN_WARNING
"Cannot alloc root domain\n");
8705 return sa_rootdomain
;
8708 static struct sched_domain
*__build_numa_sched_domains(struct s_data
*d
,
8709 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
, int i
)
8711 struct sched_domain
*sd
= NULL
;
8713 struct sched_domain
*parent
;
8716 if (cpumask_weight(cpu_map
) >
8717 SD_NODES_PER_DOMAIN
* cpumask_weight(d
->nodemask
)) {
8718 sd
= &per_cpu(allnodes_domains
, i
).sd
;
8719 SD_INIT(sd
, ALLNODES
);
8720 set_domain_attribute(sd
, attr
);
8721 cpumask_copy(sched_domain_span(sd
), cpu_map
);
8722 cpu_to_allnodes_group(i
, cpu_map
, &sd
->groups
, d
->tmpmask
);
8727 sd
= &per_cpu(node_domains
, i
).sd
;
8729 set_domain_attribute(sd
, attr
);
8730 sched_domain_node_span(cpu_to_node(i
), sched_domain_span(sd
));
8731 sd
->parent
= parent
;
8734 cpumask_and(sched_domain_span(sd
), sched_domain_span(sd
), cpu_map
);
8739 static struct sched_domain
*__build_cpu_sched_domain(struct s_data
*d
,
8740 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
,
8741 struct sched_domain
*parent
, int i
)
8743 struct sched_domain
*sd
;
8744 sd
= &per_cpu(phys_domains
, i
).sd
;
8746 set_domain_attribute(sd
, attr
);
8747 cpumask_copy(sched_domain_span(sd
), d
->nodemask
);
8748 sd
->parent
= parent
;
8751 cpu_to_phys_group(i
, cpu_map
, &sd
->groups
, d
->tmpmask
);
8755 static struct sched_domain
*__build_mc_sched_domain(struct s_data
*d
,
8756 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
,
8757 struct sched_domain
*parent
, int i
)
8759 struct sched_domain
*sd
= parent
;
8760 #ifdef CONFIG_SCHED_MC
8761 sd
= &per_cpu(core_domains
, i
).sd
;
8763 set_domain_attribute(sd
, attr
);
8764 cpumask_and(sched_domain_span(sd
), cpu_map
, cpu_coregroup_mask(i
));
8765 sd
->parent
= parent
;
8767 cpu_to_core_group(i
, cpu_map
, &sd
->groups
, d
->tmpmask
);
8772 static struct sched_domain
*__build_smt_sched_domain(struct s_data
*d
,
8773 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
,
8774 struct sched_domain
*parent
, int i
)
8776 struct sched_domain
*sd
= parent
;
8777 #ifdef CONFIG_SCHED_SMT
8778 sd
= &per_cpu(cpu_domains
, i
).sd
;
8779 SD_INIT(sd
, SIBLING
);
8780 set_domain_attribute(sd
, attr
);
8781 cpumask_and(sched_domain_span(sd
), cpu_map
, topology_thread_cpumask(i
));
8782 sd
->parent
= parent
;
8784 cpu_to_cpu_group(i
, cpu_map
, &sd
->groups
, d
->tmpmask
);
8789 static void build_sched_groups(struct s_data
*d
, enum sched_domain_level l
,
8790 const struct cpumask
*cpu_map
, int cpu
)
8793 #ifdef CONFIG_SCHED_SMT
8794 case SD_LV_SIBLING
: /* set up CPU (sibling) groups */
8795 cpumask_and(d
->this_sibling_map
, cpu_map
,
8796 topology_thread_cpumask(cpu
));
8797 if (cpu
== cpumask_first(d
->this_sibling_map
))
8798 init_sched_build_groups(d
->this_sibling_map
, cpu_map
,
8800 d
->send_covered
, d
->tmpmask
);
8803 #ifdef CONFIG_SCHED_MC
8804 case SD_LV_MC
: /* set up multi-core groups */
8805 cpumask_and(d
->this_core_map
, cpu_map
, cpu_coregroup_mask(cpu
));
8806 if (cpu
== cpumask_first(d
->this_core_map
))
8807 init_sched_build_groups(d
->this_core_map
, cpu_map
,
8809 d
->send_covered
, d
->tmpmask
);
8812 case SD_LV_CPU
: /* set up physical groups */
8813 cpumask_and(d
->nodemask
, cpumask_of_node(cpu
), cpu_map
);
8814 if (!cpumask_empty(d
->nodemask
))
8815 init_sched_build_groups(d
->nodemask
, cpu_map
,
8817 d
->send_covered
, d
->tmpmask
);
8820 case SD_LV_ALLNODES
:
8821 init_sched_build_groups(cpu_map
, cpu_map
, &cpu_to_allnodes_group
,
8822 d
->send_covered
, d
->tmpmask
);
8831 * Build sched domains for a given set of cpus and attach the sched domains
8832 * to the individual cpus
8834 static int __build_sched_domains(const struct cpumask
*cpu_map
,
8835 struct sched_domain_attr
*attr
)
8837 enum s_alloc alloc_state
= sa_none
;
8839 struct sched_domain
*sd
;
8845 alloc_state
= __visit_domain_allocation_hell(&d
, cpu_map
);
8846 if (alloc_state
!= sa_rootdomain
)
8848 alloc_state
= sa_sched_groups
;
8851 * Set up domains for cpus specified by the cpu_map.
8853 for_each_cpu(i
, cpu_map
) {
8854 cpumask_and(d
.nodemask
, cpumask_of_node(cpu_to_node(i
)),
8857 sd
= __build_numa_sched_domains(&d
, cpu_map
, attr
, i
);
8858 sd
= __build_cpu_sched_domain(&d
, cpu_map
, attr
, sd
, i
);
8859 sd
= __build_mc_sched_domain(&d
, cpu_map
, attr
, sd
, i
);
8860 sd
= __build_smt_sched_domain(&d
, cpu_map
, attr
, sd
, i
);
8863 for_each_cpu(i
, cpu_map
) {
8864 build_sched_groups(&d
, SD_LV_SIBLING
, cpu_map
, i
);
8865 build_sched_groups(&d
, SD_LV_MC
, cpu_map
, i
);
8868 /* Set up physical groups */
8869 for (i
= 0; i
< nr_node_ids
; i
++)
8870 build_sched_groups(&d
, SD_LV_CPU
, cpu_map
, i
);
8873 /* Set up node groups */
8875 build_sched_groups(&d
, SD_LV_ALLNODES
, cpu_map
, 0);
8877 for (i
= 0; i
< nr_node_ids
; i
++)
8878 if (build_numa_sched_groups(&d
, cpu_map
, i
))
8882 /* Calculate CPU power for physical packages and nodes */
8883 #ifdef CONFIG_SCHED_SMT
8884 for_each_cpu(i
, cpu_map
) {
8885 sd
= &per_cpu(cpu_domains
, i
).sd
;
8886 init_sched_groups_power(i
, sd
);
8889 #ifdef CONFIG_SCHED_MC
8890 for_each_cpu(i
, cpu_map
) {
8891 sd
= &per_cpu(core_domains
, i
).sd
;
8892 init_sched_groups_power(i
, sd
);
8896 for_each_cpu(i
, cpu_map
) {
8897 sd
= &per_cpu(phys_domains
, i
).sd
;
8898 init_sched_groups_power(i
, sd
);
8902 for (i
= 0; i
< nr_node_ids
; i
++)
8903 init_numa_sched_groups_power(d
.sched_group_nodes
[i
]);
8905 if (d
.sd_allnodes
) {
8906 struct sched_group
*sg
;
8908 cpu_to_allnodes_group(cpumask_first(cpu_map
), cpu_map
, &sg
,
8910 init_numa_sched_groups_power(sg
);
8914 /* Attach the domains */
8915 for_each_cpu(i
, cpu_map
) {
8916 #ifdef CONFIG_SCHED_SMT
8917 sd
= &per_cpu(cpu_domains
, i
).sd
;
8918 #elif defined(CONFIG_SCHED_MC)
8919 sd
= &per_cpu(core_domains
, i
).sd
;
8921 sd
= &per_cpu(phys_domains
, i
).sd
;
8923 cpu_attach_domain(sd
, d
.rd
, i
);
8926 d
.sched_group_nodes
= NULL
; /* don't free this we still need it */
8927 __free_domain_allocs(&d
, sa_tmpmask
, cpu_map
);
8931 __free_domain_allocs(&d
, alloc_state
, cpu_map
);
8935 static int build_sched_domains(const struct cpumask
*cpu_map
)
8937 return __build_sched_domains(cpu_map
, NULL
);
8940 static cpumask_var_t
*doms_cur
; /* current sched domains */
8941 static int ndoms_cur
; /* number of sched domains in 'doms_cur' */
8942 static struct sched_domain_attr
*dattr_cur
;
8943 /* attribues of custom domains in 'doms_cur' */
8946 * Special case: If a kmalloc of a doms_cur partition (array of
8947 * cpumask) fails, then fallback to a single sched domain,
8948 * as determined by the single cpumask fallback_doms.
8950 static cpumask_var_t fallback_doms
;
8953 * arch_update_cpu_topology lets virtualized architectures update the
8954 * cpu core maps. It is supposed to return 1 if the topology changed
8955 * or 0 if it stayed the same.
8957 int __attribute__((weak
)) arch_update_cpu_topology(void)
8962 cpumask_var_t
*alloc_sched_domains(unsigned int ndoms
)
8965 cpumask_var_t
*doms
;
8967 doms
= kmalloc(sizeof(*doms
) * ndoms
, GFP_KERNEL
);
8970 for (i
= 0; i
< ndoms
; i
++) {
8971 if (!alloc_cpumask_var(&doms
[i
], GFP_KERNEL
)) {
8972 free_sched_domains(doms
, i
);
8979 void free_sched_domains(cpumask_var_t doms
[], unsigned int ndoms
)
8982 for (i
= 0; i
< ndoms
; i
++)
8983 free_cpumask_var(doms
[i
]);
8988 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
8989 * For now this just excludes isolated cpus, but could be used to
8990 * exclude other special cases in the future.
8992 static int arch_init_sched_domains(const struct cpumask
*cpu_map
)
8996 arch_update_cpu_topology();
8998 doms_cur
= alloc_sched_domains(ndoms_cur
);
9000 doms_cur
= &fallback_doms
;
9001 cpumask_andnot(doms_cur
[0], cpu_map
, cpu_isolated_map
);
9003 err
= build_sched_domains(doms_cur
[0]);
9004 register_sched_domain_sysctl();
9009 static void arch_destroy_sched_domains(const struct cpumask
*cpu_map
,
9010 struct cpumask
*tmpmask
)
9012 free_sched_groups(cpu_map
, tmpmask
);
9016 * Detach sched domains from a group of cpus specified in cpu_map
9017 * These cpus will now be attached to the NULL domain
9019 static void detach_destroy_domains(const struct cpumask
*cpu_map
)
9021 /* Save because hotplug lock held. */
9022 static DECLARE_BITMAP(tmpmask
, CONFIG_NR_CPUS
);
9025 for_each_cpu(i
, cpu_map
)
9026 cpu_attach_domain(NULL
, &def_root_domain
, i
);
9027 synchronize_sched();
9028 arch_destroy_sched_domains(cpu_map
, to_cpumask(tmpmask
));
9031 /* handle null as "default" */
9032 static int dattrs_equal(struct sched_domain_attr
*cur
, int idx_cur
,
9033 struct sched_domain_attr
*new, int idx_new
)
9035 struct sched_domain_attr tmp
;
9042 return !memcmp(cur
? (cur
+ idx_cur
) : &tmp
,
9043 new ? (new + idx_new
) : &tmp
,
9044 sizeof(struct sched_domain_attr
));
9048 * Partition sched domains as specified by the 'ndoms_new'
9049 * cpumasks in the array doms_new[] of cpumasks. This compares
9050 * doms_new[] to the current sched domain partitioning, doms_cur[].
9051 * It destroys each deleted domain and builds each new domain.
9053 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'.
9054 * The masks don't intersect (don't overlap.) We should setup one
9055 * sched domain for each mask. CPUs not in any of the cpumasks will
9056 * not be load balanced. If the same cpumask appears both in the
9057 * current 'doms_cur' domains and in the new 'doms_new', we can leave
9060 * The passed in 'doms_new' should be allocated using
9061 * alloc_sched_domains. This routine takes ownership of it and will
9062 * free_sched_domains it when done with it. If the caller failed the
9063 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1,
9064 * and partition_sched_domains() will fallback to the single partition
9065 * 'fallback_doms', it also forces the domains to be rebuilt.
9067 * If doms_new == NULL it will be replaced with cpu_online_mask.
9068 * ndoms_new == 0 is a special case for destroying existing domains,
9069 * and it will not create the default domain.
9071 * Call with hotplug lock held
9073 void partition_sched_domains(int ndoms_new
, cpumask_var_t doms_new
[],
9074 struct sched_domain_attr
*dattr_new
)
9079 mutex_lock(&sched_domains_mutex
);
9081 /* always unregister in case we don't destroy any domains */
9082 unregister_sched_domain_sysctl();
9084 /* Let architecture update cpu core mappings. */
9085 new_topology
= arch_update_cpu_topology();
9087 n
= doms_new
? ndoms_new
: 0;
9089 /* Destroy deleted domains */
9090 for (i
= 0; i
< ndoms_cur
; i
++) {
9091 for (j
= 0; j
< n
&& !new_topology
; j
++) {
9092 if (cpumask_equal(doms_cur
[i
], doms_new
[j
])
9093 && dattrs_equal(dattr_cur
, i
, dattr_new
, j
))
9096 /* no match - a current sched domain not in new doms_new[] */
9097 detach_destroy_domains(doms_cur
[i
]);
9102 if (doms_new
== NULL
) {
9104 doms_new
= &fallback_doms
;
9105 cpumask_andnot(doms_new
[0], cpu_active_mask
, cpu_isolated_map
);
9106 WARN_ON_ONCE(dattr_new
);
9109 /* Build new domains */
9110 for (i
= 0; i
< ndoms_new
; i
++) {
9111 for (j
= 0; j
< ndoms_cur
&& !new_topology
; j
++) {
9112 if (cpumask_equal(doms_new
[i
], doms_cur
[j
])
9113 && dattrs_equal(dattr_new
, i
, dattr_cur
, j
))
9116 /* no match - add a new doms_new */
9117 __build_sched_domains(doms_new
[i
],
9118 dattr_new
? dattr_new
+ i
: NULL
);
9123 /* Remember the new sched domains */
9124 if (doms_cur
!= &fallback_doms
)
9125 free_sched_domains(doms_cur
, ndoms_cur
);
9126 kfree(dattr_cur
); /* kfree(NULL) is safe */
9127 doms_cur
= doms_new
;
9128 dattr_cur
= dattr_new
;
9129 ndoms_cur
= ndoms_new
;
9131 register_sched_domain_sysctl();
9133 mutex_unlock(&sched_domains_mutex
);
9136 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
9137 static void arch_reinit_sched_domains(void)
9141 /* Destroy domains first to force the rebuild */
9142 partition_sched_domains(0, NULL
, NULL
);
9144 rebuild_sched_domains();
9148 static ssize_t
sched_power_savings_store(const char *buf
, size_t count
, int smt
)
9150 unsigned int level
= 0;
9152 if (sscanf(buf
, "%u", &level
) != 1)
9156 * level is always be positive so don't check for
9157 * level < POWERSAVINGS_BALANCE_NONE which is 0
9158 * What happens on 0 or 1 byte write,
9159 * need to check for count as well?
9162 if (level
>= MAX_POWERSAVINGS_BALANCE_LEVELS
)
9166 sched_smt_power_savings
= level
;
9168 sched_mc_power_savings
= level
;
9170 arch_reinit_sched_domains();
9175 #ifdef CONFIG_SCHED_MC
9176 static ssize_t
sched_mc_power_savings_show(struct sysdev_class
*class,
9179 return sprintf(page
, "%u\n", sched_mc_power_savings
);
9181 static ssize_t
sched_mc_power_savings_store(struct sysdev_class
*class,
9182 const char *buf
, size_t count
)
9184 return sched_power_savings_store(buf
, count
, 0);
9186 static SYSDEV_CLASS_ATTR(sched_mc_power_savings
, 0644,
9187 sched_mc_power_savings_show
,
9188 sched_mc_power_savings_store
);
9191 #ifdef CONFIG_SCHED_SMT
9192 static ssize_t
sched_smt_power_savings_show(struct sysdev_class
*dev
,
9195 return sprintf(page
, "%u\n", sched_smt_power_savings
);
9197 static ssize_t
sched_smt_power_savings_store(struct sysdev_class
*dev
,
9198 const char *buf
, size_t count
)
9200 return sched_power_savings_store(buf
, count
, 1);
9202 static SYSDEV_CLASS_ATTR(sched_smt_power_savings
, 0644,
9203 sched_smt_power_savings_show
,
9204 sched_smt_power_savings_store
);
9207 int __init
sched_create_sysfs_power_savings_entries(struct sysdev_class
*cls
)
9211 #ifdef CONFIG_SCHED_SMT
9213 err
= sysfs_create_file(&cls
->kset
.kobj
,
9214 &attr_sched_smt_power_savings
.attr
);
9216 #ifdef CONFIG_SCHED_MC
9217 if (!err
&& mc_capable())
9218 err
= sysfs_create_file(&cls
->kset
.kobj
,
9219 &attr_sched_mc_power_savings
.attr
);
9223 #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
9225 #ifndef CONFIG_CPUSETS
9227 * Add online and remove offline CPUs from the scheduler domains.
9228 * When cpusets are enabled they take over this function.
9230 static int update_sched_domains(struct notifier_block
*nfb
,
9231 unsigned long action
, void *hcpu
)
9235 case CPU_ONLINE_FROZEN
:
9236 case CPU_DOWN_PREPARE
:
9237 case CPU_DOWN_PREPARE_FROZEN
:
9238 case CPU_DOWN_FAILED
:
9239 case CPU_DOWN_FAILED_FROZEN
:
9240 partition_sched_domains(1, NULL
, NULL
);
9249 static int update_runtime(struct notifier_block
*nfb
,
9250 unsigned long action
, void *hcpu
)
9252 int cpu
= (int)(long)hcpu
;
9255 case CPU_DOWN_PREPARE
:
9256 case CPU_DOWN_PREPARE_FROZEN
:
9257 disable_runtime(cpu_rq(cpu
));
9260 case CPU_DOWN_FAILED
:
9261 case CPU_DOWN_FAILED_FROZEN
:
9263 case CPU_ONLINE_FROZEN
:
9264 enable_runtime(cpu_rq(cpu
));
9272 void __init
sched_init_smp(void)
9274 cpumask_var_t non_isolated_cpus
;
9276 alloc_cpumask_var(&non_isolated_cpus
, GFP_KERNEL
);
9277 alloc_cpumask_var(&fallback_doms
, GFP_KERNEL
);
9279 #if defined(CONFIG_NUMA)
9280 sched_group_nodes_bycpu
= kzalloc(nr_cpu_ids
* sizeof(void **),
9282 BUG_ON(sched_group_nodes_bycpu
== NULL
);
9285 mutex_lock(&sched_domains_mutex
);
9286 arch_init_sched_domains(cpu_active_mask
);
9287 cpumask_andnot(non_isolated_cpus
, cpu_possible_mask
, cpu_isolated_map
);
9288 if (cpumask_empty(non_isolated_cpus
))
9289 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus
);
9290 mutex_unlock(&sched_domains_mutex
);
9293 #ifndef CONFIG_CPUSETS
9294 /* XXX: Theoretical race here - CPU may be hotplugged now */
9295 hotcpu_notifier(update_sched_domains
, 0);
9298 /* RT runtime code needs to handle some hotplug events */
9299 hotcpu_notifier(update_runtime
, 0);
9303 /* Move init over to a non-isolated CPU */
9304 if (set_cpus_allowed_ptr(current
, non_isolated_cpus
) < 0)
9306 sched_init_granularity();
9307 free_cpumask_var(non_isolated_cpus
);
9309 init_sched_rt_class();
9312 void __init
sched_init_smp(void)
9314 sched_init_granularity();
9316 #endif /* CONFIG_SMP */
9318 const_debug
unsigned int sysctl_timer_migration
= 1;
9320 int in_sched_functions(unsigned long addr
)
9322 return in_lock_functions(addr
) ||
9323 (addr
>= (unsigned long)__sched_text_start
9324 && addr
< (unsigned long)__sched_text_end
);
9327 static void init_cfs_rq(struct cfs_rq
*cfs_rq
, struct rq
*rq
)
9329 cfs_rq
->tasks_timeline
= RB_ROOT
;
9330 INIT_LIST_HEAD(&cfs_rq
->tasks
);
9331 #ifdef CONFIG_FAIR_GROUP_SCHED
9334 cfs_rq
->min_vruntime
= (u64
)(-(1LL << 20));
9337 static void init_rt_rq(struct rt_rq
*rt_rq
, struct rq
*rq
)
9339 struct rt_prio_array
*array
;
9342 array
= &rt_rq
->active
;
9343 for (i
= 0; i
< MAX_RT_PRIO
; i
++) {
9344 INIT_LIST_HEAD(array
->queue
+ i
);
9345 __clear_bit(i
, array
->bitmap
);
9347 /* delimiter for bitsearch: */
9348 __set_bit(MAX_RT_PRIO
, array
->bitmap
);
9350 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
9351 rt_rq
->highest_prio
.curr
= MAX_RT_PRIO
;
9353 rt_rq
->highest_prio
.next
= MAX_RT_PRIO
;
9357 rt_rq
->rt_nr_migratory
= 0;
9358 rt_rq
->overloaded
= 0;
9359 plist_head_init(&rt_rq
->pushable_tasks
, &rq
->lock
);
9363 rt_rq
->rt_throttled
= 0;
9364 rt_rq
->rt_runtime
= 0;
9365 spin_lock_init(&rt_rq
->rt_runtime_lock
);
9367 #ifdef CONFIG_RT_GROUP_SCHED
9368 rt_rq
->rt_nr_boosted
= 0;
9373 #ifdef CONFIG_FAIR_GROUP_SCHED
9374 static void init_tg_cfs_entry(struct task_group
*tg
, struct cfs_rq
*cfs_rq
,
9375 struct sched_entity
*se
, int cpu
, int add
,
9376 struct sched_entity
*parent
)
9378 struct rq
*rq
= cpu_rq(cpu
);
9379 tg
->cfs_rq
[cpu
] = cfs_rq
;
9380 init_cfs_rq(cfs_rq
, rq
);
9383 list_add(&cfs_rq
->leaf_cfs_rq_list
, &rq
->leaf_cfs_rq_list
);
9386 /* se could be NULL for init_task_group */
9391 se
->cfs_rq
= &rq
->cfs
;
9393 se
->cfs_rq
= parent
->my_q
;
9396 se
->load
.weight
= tg
->shares
;
9397 se
->load
.inv_weight
= 0;
9398 se
->parent
= parent
;
9402 #ifdef CONFIG_RT_GROUP_SCHED
9403 static void init_tg_rt_entry(struct task_group
*tg
, struct rt_rq
*rt_rq
,
9404 struct sched_rt_entity
*rt_se
, int cpu
, int add
,
9405 struct sched_rt_entity
*parent
)
9407 struct rq
*rq
= cpu_rq(cpu
);
9409 tg
->rt_rq
[cpu
] = rt_rq
;
9410 init_rt_rq(rt_rq
, rq
);
9412 rt_rq
->rt_se
= rt_se
;
9413 rt_rq
->rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
9415 list_add(&rt_rq
->leaf_rt_rq_list
, &rq
->leaf_rt_rq_list
);
9417 tg
->rt_se
[cpu
] = rt_se
;
9422 rt_se
->rt_rq
= &rq
->rt
;
9424 rt_se
->rt_rq
= parent
->my_q
;
9426 rt_se
->my_q
= rt_rq
;
9427 rt_se
->parent
= parent
;
9428 INIT_LIST_HEAD(&rt_se
->run_list
);
9432 void __init
sched_init(void)
9435 unsigned long alloc_size
= 0, ptr
;
9437 #ifdef CONFIG_FAIR_GROUP_SCHED
9438 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
9440 #ifdef CONFIG_RT_GROUP_SCHED
9441 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
9443 #ifdef CONFIG_USER_SCHED
9446 #ifdef CONFIG_CPUMASK_OFFSTACK
9447 alloc_size
+= num_possible_cpus() * cpumask_size();
9450 ptr
= (unsigned long)kzalloc(alloc_size
, GFP_NOWAIT
);
9452 #ifdef CONFIG_FAIR_GROUP_SCHED
9453 init_task_group
.se
= (struct sched_entity
**)ptr
;
9454 ptr
+= nr_cpu_ids
* sizeof(void **);
9456 init_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
9457 ptr
+= nr_cpu_ids
* sizeof(void **);
9459 #ifdef CONFIG_USER_SCHED
9460 root_task_group
.se
= (struct sched_entity
**)ptr
;
9461 ptr
+= nr_cpu_ids
* sizeof(void **);
9463 root_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
9464 ptr
+= nr_cpu_ids
* sizeof(void **);
9465 #endif /* CONFIG_USER_SCHED */
9466 #endif /* CONFIG_FAIR_GROUP_SCHED */
9467 #ifdef CONFIG_RT_GROUP_SCHED
9468 init_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
9469 ptr
+= nr_cpu_ids
* sizeof(void **);
9471 init_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
9472 ptr
+= nr_cpu_ids
* sizeof(void **);
9474 #ifdef CONFIG_USER_SCHED
9475 root_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
9476 ptr
+= nr_cpu_ids
* sizeof(void **);
9478 root_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
9479 ptr
+= nr_cpu_ids
* sizeof(void **);
9480 #endif /* CONFIG_USER_SCHED */
9481 #endif /* CONFIG_RT_GROUP_SCHED */
9482 #ifdef CONFIG_CPUMASK_OFFSTACK
9483 for_each_possible_cpu(i
) {
9484 per_cpu(load_balance_tmpmask
, i
) = (void *)ptr
;
9485 ptr
+= cpumask_size();
9487 #endif /* CONFIG_CPUMASK_OFFSTACK */
9491 init_defrootdomain();
9494 init_rt_bandwidth(&def_rt_bandwidth
,
9495 global_rt_period(), global_rt_runtime());
9497 #ifdef CONFIG_RT_GROUP_SCHED
9498 init_rt_bandwidth(&init_task_group
.rt_bandwidth
,
9499 global_rt_period(), global_rt_runtime());
9500 #ifdef CONFIG_USER_SCHED
9501 init_rt_bandwidth(&root_task_group
.rt_bandwidth
,
9502 global_rt_period(), RUNTIME_INF
);
9503 #endif /* CONFIG_USER_SCHED */
9504 #endif /* CONFIG_RT_GROUP_SCHED */
9506 #ifdef CONFIG_GROUP_SCHED
9507 list_add(&init_task_group
.list
, &task_groups
);
9508 INIT_LIST_HEAD(&init_task_group
.children
);
9510 #ifdef CONFIG_USER_SCHED
9511 INIT_LIST_HEAD(&root_task_group
.children
);
9512 init_task_group
.parent
= &root_task_group
;
9513 list_add(&init_task_group
.siblings
, &root_task_group
.children
);
9514 #endif /* CONFIG_USER_SCHED */
9515 #endif /* CONFIG_GROUP_SCHED */
9517 #if defined CONFIG_FAIR_GROUP_SCHED && defined CONFIG_SMP
9518 update_shares_data
= __alloc_percpu(nr_cpu_ids
* sizeof(unsigned long),
9519 __alignof__(unsigned long));
9521 for_each_possible_cpu(i
) {
9525 spin_lock_init(&rq
->lock
);
9527 rq
->calc_load_active
= 0;
9528 rq
->calc_load_update
= jiffies
+ LOAD_FREQ
;
9529 init_cfs_rq(&rq
->cfs
, rq
);
9530 init_rt_rq(&rq
->rt
, rq
);
9531 #ifdef CONFIG_FAIR_GROUP_SCHED
9532 init_task_group
.shares
= init_task_group_load
;
9533 INIT_LIST_HEAD(&rq
->leaf_cfs_rq_list
);
9534 #ifdef CONFIG_CGROUP_SCHED
9536 * How much cpu bandwidth does init_task_group get?
9538 * In case of task-groups formed thr' the cgroup filesystem, it
9539 * gets 100% of the cpu resources in the system. This overall
9540 * system cpu resource is divided among the tasks of
9541 * init_task_group and its child task-groups in a fair manner,
9542 * based on each entity's (task or task-group's) weight
9543 * (se->load.weight).
9545 * In other words, if init_task_group has 10 tasks of weight
9546 * 1024) and two child groups A0 and A1 (of weight 1024 each),
9547 * then A0's share of the cpu resource is:
9549 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
9551 * We achieve this by letting init_task_group's tasks sit
9552 * directly in rq->cfs (i.e init_task_group->se[] = NULL).
9554 init_tg_cfs_entry(&init_task_group
, &rq
->cfs
, NULL
, i
, 1, NULL
);
9555 #elif defined CONFIG_USER_SCHED
9556 root_task_group
.shares
= NICE_0_LOAD
;
9557 init_tg_cfs_entry(&root_task_group
, &rq
->cfs
, NULL
, i
, 0, NULL
);
9559 * In case of task-groups formed thr' the user id of tasks,
9560 * init_task_group represents tasks belonging to root user.
9561 * Hence it forms a sibling of all subsequent groups formed.
9562 * In this case, init_task_group gets only a fraction of overall
9563 * system cpu resource, based on the weight assigned to root
9564 * user's cpu share (INIT_TASK_GROUP_LOAD). This is accomplished
9565 * by letting tasks of init_task_group sit in a separate cfs_rq
9566 * (init_tg_cfs_rq) and having one entity represent this group of
9567 * tasks in rq->cfs (i.e init_task_group->se[] != NULL).
9569 init_tg_cfs_entry(&init_task_group
,
9570 &per_cpu(init_tg_cfs_rq
, i
),
9571 &per_cpu(init_sched_entity
, i
), i
, 1,
9572 root_task_group
.se
[i
]);
9575 #endif /* CONFIG_FAIR_GROUP_SCHED */
9577 rq
->rt
.rt_runtime
= def_rt_bandwidth
.rt_runtime
;
9578 #ifdef CONFIG_RT_GROUP_SCHED
9579 INIT_LIST_HEAD(&rq
->leaf_rt_rq_list
);
9580 #ifdef CONFIG_CGROUP_SCHED
9581 init_tg_rt_entry(&init_task_group
, &rq
->rt
, NULL
, i
, 1, NULL
);
9582 #elif defined CONFIG_USER_SCHED
9583 init_tg_rt_entry(&root_task_group
, &rq
->rt
, NULL
, i
, 0, NULL
);
9584 init_tg_rt_entry(&init_task_group
,
9585 &per_cpu(init_rt_rq
, i
),
9586 &per_cpu(init_sched_rt_entity
, i
), i
, 1,
9587 root_task_group
.rt_se
[i
]);
9591 for (j
= 0; j
< CPU_LOAD_IDX_MAX
; j
++)
9592 rq
->cpu_load
[j
] = 0;
9596 rq
->post_schedule
= 0;
9597 rq
->active_balance
= 0;
9598 rq
->next_balance
= jiffies
;
9602 rq
->migration_thread
= NULL
;
9604 rq
->avg_idle
= 2*sysctl_sched_migration_cost
;
9605 INIT_LIST_HEAD(&rq
->migration_queue
);
9606 rq_attach_root(rq
, &def_root_domain
);
9609 atomic_set(&rq
->nr_iowait
, 0);
9612 set_load_weight(&init_task
);
9614 #ifdef CONFIG_PREEMPT_NOTIFIERS
9615 INIT_HLIST_HEAD(&init_task
.preempt_notifiers
);
9619 open_softirq(SCHED_SOFTIRQ
, run_rebalance_domains
);
9622 #ifdef CONFIG_RT_MUTEXES
9623 plist_head_init(&init_task
.pi_waiters
, &init_task
.pi_lock
);
9627 * The boot idle thread does lazy MMU switching as well:
9629 atomic_inc(&init_mm
.mm_count
);
9630 enter_lazy_tlb(&init_mm
, current
);
9633 * Make us the idle thread. Technically, schedule() should not be
9634 * called from this thread, however somewhere below it might be,
9635 * but because we are the idle thread, we just pick up running again
9636 * when this runqueue becomes "idle".
9638 init_idle(current
, smp_processor_id());
9640 calc_load_update
= jiffies
+ LOAD_FREQ
;
9643 * During early bootup we pretend to be a normal task:
9645 current
->sched_class
= &fair_sched_class
;
9647 /* Allocate the nohz_cpu_mask if CONFIG_CPUMASK_OFFSTACK */
9648 zalloc_cpumask_var(&nohz_cpu_mask
, GFP_NOWAIT
);
9651 zalloc_cpumask_var(&nohz
.cpu_mask
, GFP_NOWAIT
);
9652 alloc_cpumask_var(&nohz
.ilb_grp_nohz_mask
, GFP_NOWAIT
);
9654 /* May be allocated at isolcpus cmdline parse time */
9655 if (cpu_isolated_map
== NULL
)
9656 zalloc_cpumask_var(&cpu_isolated_map
, GFP_NOWAIT
);
9661 scheduler_running
= 1;
9664 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
9665 static inline int preempt_count_equals(int preempt_offset
)
9667 int nested
= preempt_count() & ~PREEMPT_ACTIVE
;
9669 return (nested
== PREEMPT_INATOMIC_BASE
+ preempt_offset
);
9672 void __might_sleep(char *file
, int line
, int preempt_offset
)
9675 static unsigned long prev_jiffy
; /* ratelimiting */
9677 if ((preempt_count_equals(preempt_offset
) && !irqs_disabled()) ||
9678 system_state
!= SYSTEM_RUNNING
|| oops_in_progress
)
9680 if (time_before(jiffies
, prev_jiffy
+ HZ
) && prev_jiffy
)
9682 prev_jiffy
= jiffies
;
9685 "BUG: sleeping function called from invalid context at %s:%d\n",
9688 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
9689 in_atomic(), irqs_disabled(),
9690 current
->pid
, current
->comm
);
9692 debug_show_held_locks(current
);
9693 if (irqs_disabled())
9694 print_irqtrace_events(current
);
9698 EXPORT_SYMBOL(__might_sleep
);
9701 #ifdef CONFIG_MAGIC_SYSRQ
9702 static void normalize_task(struct rq
*rq
, struct task_struct
*p
)
9706 update_rq_clock(rq
);
9707 on_rq
= p
->se
.on_rq
;
9709 deactivate_task(rq
, p
, 0);
9710 __setscheduler(rq
, p
, SCHED_NORMAL
, 0);
9712 activate_task(rq
, p
, 0);
9713 resched_task(rq
->curr
);
9717 void normalize_rt_tasks(void)
9719 struct task_struct
*g
, *p
;
9720 unsigned long flags
;
9723 read_lock_irqsave(&tasklist_lock
, flags
);
9724 do_each_thread(g
, p
) {
9726 * Only normalize user tasks:
9731 p
->se
.exec_start
= 0;
9732 #ifdef CONFIG_SCHEDSTATS
9733 p
->se
.wait_start
= 0;
9734 p
->se
.sleep_start
= 0;
9735 p
->se
.block_start
= 0;
9740 * Renice negative nice level userspace
9743 if (TASK_NICE(p
) < 0 && p
->mm
)
9744 set_user_nice(p
, 0);
9748 spin_lock(&p
->pi_lock
);
9749 rq
= __task_rq_lock(p
);
9751 normalize_task(rq
, p
);
9753 __task_rq_unlock(rq
);
9754 spin_unlock(&p
->pi_lock
);
9755 } while_each_thread(g
, p
);
9757 read_unlock_irqrestore(&tasklist_lock
, flags
);
9760 #endif /* CONFIG_MAGIC_SYSRQ */
9764 * These functions are only useful for the IA64 MCA handling.
9766 * They can only be called when the whole system has been
9767 * stopped - every CPU needs to be quiescent, and no scheduling
9768 * activity can take place. Using them for anything else would
9769 * be a serious bug, and as a result, they aren't even visible
9770 * under any other configuration.
9774 * curr_task - return the current task for a given cpu.
9775 * @cpu: the processor in question.
9777 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
9779 struct task_struct
*curr_task(int cpu
)
9781 return cpu_curr(cpu
);
9785 * set_curr_task - set the current task for a given cpu.
9786 * @cpu: the processor in question.
9787 * @p: the task pointer to set.
9789 * Description: This function must only be used when non-maskable interrupts
9790 * are serviced on a separate stack. It allows the architecture to switch the
9791 * notion of the current task on a cpu in a non-blocking manner. This function
9792 * must be called with all CPU's synchronized, and interrupts disabled, the
9793 * and caller must save the original value of the current task (see
9794 * curr_task() above) and restore that value before reenabling interrupts and
9795 * re-starting the system.
9797 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
9799 void set_curr_task(int cpu
, struct task_struct
*p
)
9806 #ifdef CONFIG_FAIR_GROUP_SCHED
9807 static void free_fair_sched_group(struct task_group
*tg
)
9811 for_each_possible_cpu(i
) {
9813 kfree(tg
->cfs_rq
[i
]);
9823 int alloc_fair_sched_group(struct task_group
*tg
, struct task_group
*parent
)
9825 struct cfs_rq
*cfs_rq
;
9826 struct sched_entity
*se
;
9830 tg
->cfs_rq
= kzalloc(sizeof(cfs_rq
) * nr_cpu_ids
, GFP_KERNEL
);
9833 tg
->se
= kzalloc(sizeof(se
) * nr_cpu_ids
, GFP_KERNEL
);
9837 tg
->shares
= NICE_0_LOAD
;
9839 for_each_possible_cpu(i
) {
9842 cfs_rq
= kzalloc_node(sizeof(struct cfs_rq
),
9843 GFP_KERNEL
, cpu_to_node(i
));
9847 se
= kzalloc_node(sizeof(struct sched_entity
),
9848 GFP_KERNEL
, cpu_to_node(i
));
9852 init_tg_cfs_entry(tg
, cfs_rq
, se
, i
, 0, parent
->se
[i
]);
9861 static inline void register_fair_sched_group(struct task_group
*tg
, int cpu
)
9863 list_add_rcu(&tg
->cfs_rq
[cpu
]->leaf_cfs_rq_list
,
9864 &cpu_rq(cpu
)->leaf_cfs_rq_list
);
9867 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
9869 list_del_rcu(&tg
->cfs_rq
[cpu
]->leaf_cfs_rq_list
);
9871 #else /* !CONFG_FAIR_GROUP_SCHED */
9872 static inline void free_fair_sched_group(struct task_group
*tg
)
9877 int alloc_fair_sched_group(struct task_group
*tg
, struct task_group
*parent
)
9882 static inline void register_fair_sched_group(struct task_group
*tg
, int cpu
)
9886 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
9889 #endif /* CONFIG_FAIR_GROUP_SCHED */
9891 #ifdef CONFIG_RT_GROUP_SCHED
9892 static void free_rt_sched_group(struct task_group
*tg
)
9896 destroy_rt_bandwidth(&tg
->rt_bandwidth
);
9898 for_each_possible_cpu(i
) {
9900 kfree(tg
->rt_rq
[i
]);
9902 kfree(tg
->rt_se
[i
]);
9910 int alloc_rt_sched_group(struct task_group
*tg
, struct task_group
*parent
)
9912 struct rt_rq
*rt_rq
;
9913 struct sched_rt_entity
*rt_se
;
9917 tg
->rt_rq
= kzalloc(sizeof(rt_rq
) * nr_cpu_ids
, GFP_KERNEL
);
9920 tg
->rt_se
= kzalloc(sizeof(rt_se
) * nr_cpu_ids
, GFP_KERNEL
);
9924 init_rt_bandwidth(&tg
->rt_bandwidth
,
9925 ktime_to_ns(def_rt_bandwidth
.rt_period
), 0);
9927 for_each_possible_cpu(i
) {
9930 rt_rq
= kzalloc_node(sizeof(struct rt_rq
),
9931 GFP_KERNEL
, cpu_to_node(i
));
9935 rt_se
= kzalloc_node(sizeof(struct sched_rt_entity
),
9936 GFP_KERNEL
, cpu_to_node(i
));
9940 init_tg_rt_entry(tg
, rt_rq
, rt_se
, i
, 0, parent
->rt_se
[i
]);
9949 static inline void register_rt_sched_group(struct task_group
*tg
, int cpu
)
9951 list_add_rcu(&tg
->rt_rq
[cpu
]->leaf_rt_rq_list
,
9952 &cpu_rq(cpu
)->leaf_rt_rq_list
);
9955 static inline void unregister_rt_sched_group(struct task_group
*tg
, int cpu
)
9957 list_del_rcu(&tg
->rt_rq
[cpu
]->leaf_rt_rq_list
);
9959 #else /* !CONFIG_RT_GROUP_SCHED */
9960 static inline void free_rt_sched_group(struct task_group
*tg
)
9965 int alloc_rt_sched_group(struct task_group
*tg
, struct task_group
*parent
)
9970 static inline void register_rt_sched_group(struct task_group
*tg
, int cpu
)
9974 static inline void unregister_rt_sched_group(struct task_group
*tg
, int cpu
)
9977 #endif /* CONFIG_RT_GROUP_SCHED */
9979 #ifdef CONFIG_GROUP_SCHED
9980 static void free_sched_group(struct task_group
*tg
)
9982 free_fair_sched_group(tg
);
9983 free_rt_sched_group(tg
);
9987 /* allocate runqueue etc for a new task group */
9988 struct task_group
*sched_create_group(struct task_group
*parent
)
9990 struct task_group
*tg
;
9991 unsigned long flags
;
9994 tg
= kzalloc(sizeof(*tg
), GFP_KERNEL
);
9996 return ERR_PTR(-ENOMEM
);
9998 if (!alloc_fair_sched_group(tg
, parent
))
10001 if (!alloc_rt_sched_group(tg
, parent
))
10004 spin_lock_irqsave(&task_group_lock
, flags
);
10005 for_each_possible_cpu(i
) {
10006 register_fair_sched_group(tg
, i
);
10007 register_rt_sched_group(tg
, i
);
10009 list_add_rcu(&tg
->list
, &task_groups
);
10011 WARN_ON(!parent
); /* root should already exist */
10013 tg
->parent
= parent
;
10014 INIT_LIST_HEAD(&tg
->children
);
10015 list_add_rcu(&tg
->siblings
, &parent
->children
);
10016 spin_unlock_irqrestore(&task_group_lock
, flags
);
10021 free_sched_group(tg
);
10022 return ERR_PTR(-ENOMEM
);
10025 /* rcu callback to free various structures associated with a task group */
10026 static void free_sched_group_rcu(struct rcu_head
*rhp
)
10028 /* now it should be safe to free those cfs_rqs */
10029 free_sched_group(container_of(rhp
, struct task_group
, rcu
));
10032 /* Destroy runqueue etc associated with a task group */
10033 void sched_destroy_group(struct task_group
*tg
)
10035 unsigned long flags
;
10038 spin_lock_irqsave(&task_group_lock
, flags
);
10039 for_each_possible_cpu(i
) {
10040 unregister_fair_sched_group(tg
, i
);
10041 unregister_rt_sched_group(tg
, i
);
10043 list_del_rcu(&tg
->list
);
10044 list_del_rcu(&tg
->siblings
);
10045 spin_unlock_irqrestore(&task_group_lock
, flags
);
10047 /* wait for possible concurrent references to cfs_rqs complete */
10048 call_rcu(&tg
->rcu
, free_sched_group_rcu
);
10051 /* change task's runqueue when it moves between groups.
10052 * The caller of this function should have put the task in its new group
10053 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
10054 * reflect its new group.
10056 void sched_move_task(struct task_struct
*tsk
)
10058 int on_rq
, running
;
10059 unsigned long flags
;
10062 rq
= task_rq_lock(tsk
, &flags
);
10064 update_rq_clock(rq
);
10066 running
= task_current(rq
, tsk
);
10067 on_rq
= tsk
->se
.on_rq
;
10070 dequeue_task(rq
, tsk
, 0);
10071 if (unlikely(running
))
10072 tsk
->sched_class
->put_prev_task(rq
, tsk
);
10074 set_task_rq(tsk
, task_cpu(tsk
));
10076 #ifdef CONFIG_FAIR_GROUP_SCHED
10077 if (tsk
->sched_class
->moved_group
)
10078 tsk
->sched_class
->moved_group(tsk
);
10081 if (unlikely(running
))
10082 tsk
->sched_class
->set_curr_task(rq
);
10084 enqueue_task(rq
, tsk
, 0);
10086 task_rq_unlock(rq
, &flags
);
10088 #endif /* CONFIG_GROUP_SCHED */
10090 #ifdef CONFIG_FAIR_GROUP_SCHED
10091 static void __set_se_shares(struct sched_entity
*se
, unsigned long shares
)
10093 struct cfs_rq
*cfs_rq
= se
->cfs_rq
;
10098 dequeue_entity(cfs_rq
, se
, 0);
10100 se
->load
.weight
= shares
;
10101 se
->load
.inv_weight
= 0;
10104 enqueue_entity(cfs_rq
, se
, 0);
10107 static void set_se_shares(struct sched_entity
*se
, unsigned long shares
)
10109 struct cfs_rq
*cfs_rq
= se
->cfs_rq
;
10110 struct rq
*rq
= cfs_rq
->rq
;
10111 unsigned long flags
;
10113 spin_lock_irqsave(&rq
->lock
, flags
);
10114 __set_se_shares(se
, shares
);
10115 spin_unlock_irqrestore(&rq
->lock
, flags
);
10118 static DEFINE_MUTEX(shares_mutex
);
10120 int sched_group_set_shares(struct task_group
*tg
, unsigned long shares
)
10123 unsigned long flags
;
10126 * We can't change the weight of the root cgroup.
10131 if (shares
< MIN_SHARES
)
10132 shares
= MIN_SHARES
;
10133 else if (shares
> MAX_SHARES
)
10134 shares
= MAX_SHARES
;
10136 mutex_lock(&shares_mutex
);
10137 if (tg
->shares
== shares
)
10140 spin_lock_irqsave(&task_group_lock
, flags
);
10141 for_each_possible_cpu(i
)
10142 unregister_fair_sched_group(tg
, i
);
10143 list_del_rcu(&tg
->siblings
);
10144 spin_unlock_irqrestore(&task_group_lock
, flags
);
10146 /* wait for any ongoing reference to this group to finish */
10147 synchronize_sched();
10150 * Now we are free to modify the group's share on each cpu
10151 * w/o tripping rebalance_share or load_balance_fair.
10153 tg
->shares
= shares
;
10154 for_each_possible_cpu(i
) {
10156 * force a rebalance
10158 cfs_rq_set_shares(tg
->cfs_rq
[i
], 0);
10159 set_se_shares(tg
->se
[i
], shares
);
10163 * Enable load balance activity on this group, by inserting it back on
10164 * each cpu's rq->leaf_cfs_rq_list.
10166 spin_lock_irqsave(&task_group_lock
, flags
);
10167 for_each_possible_cpu(i
)
10168 register_fair_sched_group(tg
, i
);
10169 list_add_rcu(&tg
->siblings
, &tg
->parent
->children
);
10170 spin_unlock_irqrestore(&task_group_lock
, flags
);
10172 mutex_unlock(&shares_mutex
);
10176 unsigned long sched_group_shares(struct task_group
*tg
)
10182 #ifdef CONFIG_RT_GROUP_SCHED
10184 * Ensure that the real time constraints are schedulable.
10186 static DEFINE_MUTEX(rt_constraints_mutex
);
10188 static unsigned long to_ratio(u64 period
, u64 runtime
)
10190 if (runtime
== RUNTIME_INF
)
10193 return div64_u64(runtime
<< 20, period
);
10196 /* Must be called with tasklist_lock held */
10197 static inline int tg_has_rt_tasks(struct task_group
*tg
)
10199 struct task_struct
*g
, *p
;
10201 do_each_thread(g
, p
) {
10202 if (rt_task(p
) && rt_rq_of_se(&p
->rt
)->tg
== tg
)
10204 } while_each_thread(g
, p
);
10209 struct rt_schedulable_data
{
10210 struct task_group
*tg
;
10215 static int tg_schedulable(struct task_group
*tg
, void *data
)
10217 struct rt_schedulable_data
*d
= data
;
10218 struct task_group
*child
;
10219 unsigned long total
, sum
= 0;
10220 u64 period
, runtime
;
10222 period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
10223 runtime
= tg
->rt_bandwidth
.rt_runtime
;
10226 period
= d
->rt_period
;
10227 runtime
= d
->rt_runtime
;
10230 #ifdef CONFIG_USER_SCHED
10231 if (tg
== &root_task_group
) {
10232 period
= global_rt_period();
10233 runtime
= global_rt_runtime();
10238 * Cannot have more runtime than the period.
10240 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
10244 * Ensure we don't starve existing RT tasks.
10246 if (rt_bandwidth_enabled() && !runtime
&& tg_has_rt_tasks(tg
))
10249 total
= to_ratio(period
, runtime
);
10252 * Nobody can have more than the global setting allows.
10254 if (total
> to_ratio(global_rt_period(), global_rt_runtime()))
10258 * The sum of our children's runtime should not exceed our own.
10260 list_for_each_entry_rcu(child
, &tg
->children
, siblings
) {
10261 period
= ktime_to_ns(child
->rt_bandwidth
.rt_period
);
10262 runtime
= child
->rt_bandwidth
.rt_runtime
;
10264 if (child
== d
->tg
) {
10265 period
= d
->rt_period
;
10266 runtime
= d
->rt_runtime
;
10269 sum
+= to_ratio(period
, runtime
);
10278 static int __rt_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
)
10280 struct rt_schedulable_data data
= {
10282 .rt_period
= period
,
10283 .rt_runtime
= runtime
,
10286 return walk_tg_tree(tg_schedulable
, tg_nop
, &data
);
10289 static int tg_set_bandwidth(struct task_group
*tg
,
10290 u64 rt_period
, u64 rt_runtime
)
10294 mutex_lock(&rt_constraints_mutex
);
10295 read_lock(&tasklist_lock
);
10296 err
= __rt_schedulable(tg
, rt_period
, rt_runtime
);
10300 spin_lock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
10301 tg
->rt_bandwidth
.rt_period
= ns_to_ktime(rt_period
);
10302 tg
->rt_bandwidth
.rt_runtime
= rt_runtime
;
10304 for_each_possible_cpu(i
) {
10305 struct rt_rq
*rt_rq
= tg
->rt_rq
[i
];
10307 spin_lock(&rt_rq
->rt_runtime_lock
);
10308 rt_rq
->rt_runtime
= rt_runtime
;
10309 spin_unlock(&rt_rq
->rt_runtime_lock
);
10311 spin_unlock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
10313 read_unlock(&tasklist_lock
);
10314 mutex_unlock(&rt_constraints_mutex
);
10319 int sched_group_set_rt_runtime(struct task_group
*tg
, long rt_runtime_us
)
10321 u64 rt_runtime
, rt_period
;
10323 rt_period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
10324 rt_runtime
= (u64
)rt_runtime_us
* NSEC_PER_USEC
;
10325 if (rt_runtime_us
< 0)
10326 rt_runtime
= RUNTIME_INF
;
10328 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
10331 long sched_group_rt_runtime(struct task_group
*tg
)
10335 if (tg
->rt_bandwidth
.rt_runtime
== RUNTIME_INF
)
10338 rt_runtime_us
= tg
->rt_bandwidth
.rt_runtime
;
10339 do_div(rt_runtime_us
, NSEC_PER_USEC
);
10340 return rt_runtime_us
;
10343 int sched_group_set_rt_period(struct task_group
*tg
, long rt_period_us
)
10345 u64 rt_runtime
, rt_period
;
10347 rt_period
= (u64
)rt_period_us
* NSEC_PER_USEC
;
10348 rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
10350 if (rt_period
== 0)
10353 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
10356 long sched_group_rt_period(struct task_group
*tg
)
10360 rt_period_us
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
10361 do_div(rt_period_us
, NSEC_PER_USEC
);
10362 return rt_period_us
;
10365 static int sched_rt_global_constraints(void)
10367 u64 runtime
, period
;
10370 if (sysctl_sched_rt_period
<= 0)
10373 runtime
= global_rt_runtime();
10374 period
= global_rt_period();
10377 * Sanity check on the sysctl variables.
10379 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
10382 mutex_lock(&rt_constraints_mutex
);
10383 read_lock(&tasklist_lock
);
10384 ret
= __rt_schedulable(NULL
, 0, 0);
10385 read_unlock(&tasklist_lock
);
10386 mutex_unlock(&rt_constraints_mutex
);
10391 int sched_rt_can_attach(struct task_group
*tg
, struct task_struct
*tsk
)
10393 /* Don't accept realtime tasks when there is no way for them to run */
10394 if (rt_task(tsk
) && tg
->rt_bandwidth
.rt_runtime
== 0)
10400 #else /* !CONFIG_RT_GROUP_SCHED */
10401 static int sched_rt_global_constraints(void)
10403 unsigned long flags
;
10406 if (sysctl_sched_rt_period
<= 0)
10410 * There's always some RT tasks in the root group
10411 * -- migration, kstopmachine etc..
10413 if (sysctl_sched_rt_runtime
== 0)
10416 spin_lock_irqsave(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
10417 for_each_possible_cpu(i
) {
10418 struct rt_rq
*rt_rq
= &cpu_rq(i
)->rt
;
10420 spin_lock(&rt_rq
->rt_runtime_lock
);
10421 rt_rq
->rt_runtime
= global_rt_runtime();
10422 spin_unlock(&rt_rq
->rt_runtime_lock
);
10424 spin_unlock_irqrestore(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
10428 #endif /* CONFIG_RT_GROUP_SCHED */
10430 int sched_rt_handler(struct ctl_table
*table
, int write
,
10431 void __user
*buffer
, size_t *lenp
,
10435 int old_period
, old_runtime
;
10436 static DEFINE_MUTEX(mutex
);
10438 mutex_lock(&mutex
);
10439 old_period
= sysctl_sched_rt_period
;
10440 old_runtime
= sysctl_sched_rt_runtime
;
10442 ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
10444 if (!ret
&& write
) {
10445 ret
= sched_rt_global_constraints();
10447 sysctl_sched_rt_period
= old_period
;
10448 sysctl_sched_rt_runtime
= old_runtime
;
10450 def_rt_bandwidth
.rt_runtime
= global_rt_runtime();
10451 def_rt_bandwidth
.rt_period
=
10452 ns_to_ktime(global_rt_period());
10455 mutex_unlock(&mutex
);
10460 #ifdef CONFIG_CGROUP_SCHED
10462 /* return corresponding task_group object of a cgroup */
10463 static inline struct task_group
*cgroup_tg(struct cgroup
*cgrp
)
10465 return container_of(cgroup_subsys_state(cgrp
, cpu_cgroup_subsys_id
),
10466 struct task_group
, css
);
10469 static struct cgroup_subsys_state
*
10470 cpu_cgroup_create(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
10472 struct task_group
*tg
, *parent
;
10474 if (!cgrp
->parent
) {
10475 /* This is early initialization for the top cgroup */
10476 return &init_task_group
.css
;
10479 parent
= cgroup_tg(cgrp
->parent
);
10480 tg
= sched_create_group(parent
);
10482 return ERR_PTR(-ENOMEM
);
10488 cpu_cgroup_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
10490 struct task_group
*tg
= cgroup_tg(cgrp
);
10492 sched_destroy_group(tg
);
10496 cpu_cgroup_can_attach_task(struct cgroup
*cgrp
, struct task_struct
*tsk
)
10498 #ifdef CONFIG_RT_GROUP_SCHED
10499 if (!sched_rt_can_attach(cgroup_tg(cgrp
), tsk
))
10502 /* We don't support RT-tasks being in separate groups */
10503 if (tsk
->sched_class
!= &fair_sched_class
)
10510 cpu_cgroup_can_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
10511 struct task_struct
*tsk
, bool threadgroup
)
10513 int retval
= cpu_cgroup_can_attach_task(cgrp
, tsk
);
10517 struct task_struct
*c
;
10519 list_for_each_entry_rcu(c
, &tsk
->thread_group
, thread_group
) {
10520 retval
= cpu_cgroup_can_attach_task(cgrp
, c
);
10532 cpu_cgroup_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
10533 struct cgroup
*old_cont
, struct task_struct
*tsk
,
10536 sched_move_task(tsk
);
10538 struct task_struct
*c
;
10540 list_for_each_entry_rcu(c
, &tsk
->thread_group
, thread_group
) {
10541 sched_move_task(c
);
10547 #ifdef CONFIG_FAIR_GROUP_SCHED
10548 static int cpu_shares_write_u64(struct cgroup
*cgrp
, struct cftype
*cftype
,
10551 return sched_group_set_shares(cgroup_tg(cgrp
), shareval
);
10554 static u64
cpu_shares_read_u64(struct cgroup
*cgrp
, struct cftype
*cft
)
10556 struct task_group
*tg
= cgroup_tg(cgrp
);
10558 return (u64
) tg
->shares
;
10560 #endif /* CONFIG_FAIR_GROUP_SCHED */
10562 #ifdef CONFIG_RT_GROUP_SCHED
10563 static int cpu_rt_runtime_write(struct cgroup
*cgrp
, struct cftype
*cft
,
10566 return sched_group_set_rt_runtime(cgroup_tg(cgrp
), val
);
10569 static s64
cpu_rt_runtime_read(struct cgroup
*cgrp
, struct cftype
*cft
)
10571 return sched_group_rt_runtime(cgroup_tg(cgrp
));
10574 static int cpu_rt_period_write_uint(struct cgroup
*cgrp
, struct cftype
*cftype
,
10577 return sched_group_set_rt_period(cgroup_tg(cgrp
), rt_period_us
);
10580 static u64
cpu_rt_period_read_uint(struct cgroup
*cgrp
, struct cftype
*cft
)
10582 return sched_group_rt_period(cgroup_tg(cgrp
));
10584 #endif /* CONFIG_RT_GROUP_SCHED */
10586 static struct cftype cpu_files
[] = {
10587 #ifdef CONFIG_FAIR_GROUP_SCHED
10590 .read_u64
= cpu_shares_read_u64
,
10591 .write_u64
= cpu_shares_write_u64
,
10594 #ifdef CONFIG_RT_GROUP_SCHED
10596 .name
= "rt_runtime_us",
10597 .read_s64
= cpu_rt_runtime_read
,
10598 .write_s64
= cpu_rt_runtime_write
,
10601 .name
= "rt_period_us",
10602 .read_u64
= cpu_rt_period_read_uint
,
10603 .write_u64
= cpu_rt_period_write_uint
,
10608 static int cpu_cgroup_populate(struct cgroup_subsys
*ss
, struct cgroup
*cont
)
10610 return cgroup_add_files(cont
, ss
, cpu_files
, ARRAY_SIZE(cpu_files
));
10613 struct cgroup_subsys cpu_cgroup_subsys
= {
10615 .create
= cpu_cgroup_create
,
10616 .destroy
= cpu_cgroup_destroy
,
10617 .can_attach
= cpu_cgroup_can_attach
,
10618 .attach
= cpu_cgroup_attach
,
10619 .populate
= cpu_cgroup_populate
,
10620 .subsys_id
= cpu_cgroup_subsys_id
,
10624 #endif /* CONFIG_CGROUP_SCHED */
10626 #ifdef CONFIG_CGROUP_CPUACCT
10629 * CPU accounting code for task groups.
10631 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
10632 * (balbir@in.ibm.com).
10635 /* track cpu usage of a group of tasks and its child groups */
10637 struct cgroup_subsys_state css
;
10638 /* cpuusage holds pointer to a u64-type object on every cpu */
10640 struct percpu_counter cpustat
[CPUACCT_STAT_NSTATS
];
10641 struct cpuacct
*parent
;
10644 struct cgroup_subsys cpuacct_subsys
;
10646 /* return cpu accounting group corresponding to this container */
10647 static inline struct cpuacct
*cgroup_ca(struct cgroup
*cgrp
)
10649 return container_of(cgroup_subsys_state(cgrp
, cpuacct_subsys_id
),
10650 struct cpuacct
, css
);
10653 /* return cpu accounting group to which this task belongs */
10654 static inline struct cpuacct
*task_ca(struct task_struct
*tsk
)
10656 return container_of(task_subsys_state(tsk
, cpuacct_subsys_id
),
10657 struct cpuacct
, css
);
10660 /* create a new cpu accounting group */
10661 static struct cgroup_subsys_state
*cpuacct_create(
10662 struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
10664 struct cpuacct
*ca
= kzalloc(sizeof(*ca
), GFP_KERNEL
);
10670 ca
->cpuusage
= alloc_percpu(u64
);
10674 for (i
= 0; i
< CPUACCT_STAT_NSTATS
; i
++)
10675 if (percpu_counter_init(&ca
->cpustat
[i
], 0))
10676 goto out_free_counters
;
10679 ca
->parent
= cgroup_ca(cgrp
->parent
);
10685 percpu_counter_destroy(&ca
->cpustat
[i
]);
10686 free_percpu(ca
->cpuusage
);
10690 return ERR_PTR(-ENOMEM
);
10693 /* destroy an existing cpu accounting group */
10695 cpuacct_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
10697 struct cpuacct
*ca
= cgroup_ca(cgrp
);
10700 for (i
= 0; i
< CPUACCT_STAT_NSTATS
; i
++)
10701 percpu_counter_destroy(&ca
->cpustat
[i
]);
10702 free_percpu(ca
->cpuusage
);
10706 static u64
cpuacct_cpuusage_read(struct cpuacct
*ca
, int cpu
)
10708 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
10711 #ifndef CONFIG_64BIT
10713 * Take rq->lock to make 64-bit read safe on 32-bit platforms.
10715 spin_lock_irq(&cpu_rq(cpu
)->lock
);
10717 spin_unlock_irq(&cpu_rq(cpu
)->lock
);
10725 static void cpuacct_cpuusage_write(struct cpuacct
*ca
, int cpu
, u64 val
)
10727 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
10729 #ifndef CONFIG_64BIT
10731 * Take rq->lock to make 64-bit write safe on 32-bit platforms.
10733 spin_lock_irq(&cpu_rq(cpu
)->lock
);
10735 spin_unlock_irq(&cpu_rq(cpu
)->lock
);
10741 /* return total cpu usage (in nanoseconds) of a group */
10742 static u64
cpuusage_read(struct cgroup
*cgrp
, struct cftype
*cft
)
10744 struct cpuacct
*ca
= cgroup_ca(cgrp
);
10745 u64 totalcpuusage
= 0;
10748 for_each_present_cpu(i
)
10749 totalcpuusage
+= cpuacct_cpuusage_read(ca
, i
);
10751 return totalcpuusage
;
10754 static int cpuusage_write(struct cgroup
*cgrp
, struct cftype
*cftype
,
10757 struct cpuacct
*ca
= cgroup_ca(cgrp
);
10766 for_each_present_cpu(i
)
10767 cpuacct_cpuusage_write(ca
, i
, 0);
10773 static int cpuacct_percpu_seq_read(struct cgroup
*cgroup
, struct cftype
*cft
,
10774 struct seq_file
*m
)
10776 struct cpuacct
*ca
= cgroup_ca(cgroup
);
10780 for_each_present_cpu(i
) {
10781 percpu
= cpuacct_cpuusage_read(ca
, i
);
10782 seq_printf(m
, "%llu ", (unsigned long long) percpu
);
10784 seq_printf(m
, "\n");
10788 static const char *cpuacct_stat_desc
[] = {
10789 [CPUACCT_STAT_USER
] = "user",
10790 [CPUACCT_STAT_SYSTEM
] = "system",
10793 static int cpuacct_stats_show(struct cgroup
*cgrp
, struct cftype
*cft
,
10794 struct cgroup_map_cb
*cb
)
10796 struct cpuacct
*ca
= cgroup_ca(cgrp
);
10799 for (i
= 0; i
< CPUACCT_STAT_NSTATS
; i
++) {
10800 s64 val
= percpu_counter_read(&ca
->cpustat
[i
]);
10801 val
= cputime64_to_clock_t(val
);
10802 cb
->fill(cb
, cpuacct_stat_desc
[i
], val
);
10807 static struct cftype files
[] = {
10810 .read_u64
= cpuusage_read
,
10811 .write_u64
= cpuusage_write
,
10814 .name
= "usage_percpu",
10815 .read_seq_string
= cpuacct_percpu_seq_read
,
10819 .read_map
= cpuacct_stats_show
,
10823 static int cpuacct_populate(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
10825 return cgroup_add_files(cgrp
, ss
, files
, ARRAY_SIZE(files
));
10829 * charge this task's execution time to its accounting group.
10831 * called with rq->lock held.
10833 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
)
10835 struct cpuacct
*ca
;
10838 if (unlikely(!cpuacct_subsys
.active
))
10841 cpu
= task_cpu(tsk
);
10847 for (; ca
; ca
= ca
->parent
) {
10848 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
10849 *cpuusage
+= cputime
;
10856 * Charge the system/user time to the task's accounting group.
10858 static void cpuacct_update_stats(struct task_struct
*tsk
,
10859 enum cpuacct_stat_index idx
, cputime_t val
)
10861 struct cpuacct
*ca
;
10863 if (unlikely(!cpuacct_subsys
.active
))
10870 percpu_counter_add(&ca
->cpustat
[idx
], val
);
10876 struct cgroup_subsys cpuacct_subsys
= {
10878 .create
= cpuacct_create
,
10879 .destroy
= cpuacct_destroy
,
10880 .populate
= cpuacct_populate
,
10881 .subsys_id
= cpuacct_subsys_id
,
10883 #endif /* CONFIG_CGROUP_CPUACCT */
10887 int rcu_expedited_torture_stats(char *page
)
10891 EXPORT_SYMBOL_GPL(rcu_expedited_torture_stats
);
10893 void synchronize_sched_expedited(void)
10896 EXPORT_SYMBOL_GPL(synchronize_sched_expedited
);
10898 #else /* #ifndef CONFIG_SMP */
10900 static DEFINE_PER_CPU(struct migration_req
, rcu_migration_req
);
10901 static DEFINE_MUTEX(rcu_sched_expedited_mutex
);
10903 #define RCU_EXPEDITED_STATE_POST -2
10904 #define RCU_EXPEDITED_STATE_IDLE -1
10906 static int rcu_expedited_state
= RCU_EXPEDITED_STATE_IDLE
;
10908 int rcu_expedited_torture_stats(char *page
)
10913 cnt
+= sprintf(&page
[cnt
], "state: %d /", rcu_expedited_state
);
10914 for_each_online_cpu(cpu
) {
10915 cnt
+= sprintf(&page
[cnt
], " %d:%d",
10916 cpu
, per_cpu(rcu_migration_req
, cpu
).dest_cpu
);
10918 cnt
+= sprintf(&page
[cnt
], "\n");
10921 EXPORT_SYMBOL_GPL(rcu_expedited_torture_stats
);
10923 static long synchronize_sched_expedited_count
;
10926 * Wait for an rcu-sched grace period to elapse, but use "big hammer"
10927 * approach to force grace period to end quickly. This consumes
10928 * significant time on all CPUs, and is thus not recommended for
10929 * any sort of common-case code.
10931 * Note that it is illegal to call this function while holding any
10932 * lock that is acquired by a CPU-hotplug notifier. Failing to
10933 * observe this restriction will result in deadlock.
10935 void synchronize_sched_expedited(void)
10938 unsigned long flags
;
10939 bool need_full_sync
= 0;
10941 struct migration_req
*req
;
10945 smp_mb(); /* ensure prior mod happens before capturing snap. */
10946 snap
= ACCESS_ONCE(synchronize_sched_expedited_count
) + 1;
10948 while (!mutex_trylock(&rcu_sched_expedited_mutex
)) {
10950 if (trycount
++ < 10)
10951 udelay(trycount
* num_online_cpus());
10953 synchronize_sched();
10956 if (ACCESS_ONCE(synchronize_sched_expedited_count
) - snap
> 0) {
10957 smp_mb(); /* ensure test happens before caller kfree */
10962 rcu_expedited_state
= RCU_EXPEDITED_STATE_POST
;
10963 for_each_online_cpu(cpu
) {
10965 req
= &per_cpu(rcu_migration_req
, cpu
);
10966 init_completion(&req
->done
);
10968 req
->dest_cpu
= RCU_MIGRATION_NEED_QS
;
10969 spin_lock_irqsave(&rq
->lock
, flags
);
10970 list_add(&req
->list
, &rq
->migration_queue
);
10971 spin_unlock_irqrestore(&rq
->lock
, flags
);
10972 wake_up_process(rq
->migration_thread
);
10974 for_each_online_cpu(cpu
) {
10975 rcu_expedited_state
= cpu
;
10976 req
= &per_cpu(rcu_migration_req
, cpu
);
10978 wait_for_completion(&req
->done
);
10979 spin_lock_irqsave(&rq
->lock
, flags
);
10980 if (unlikely(req
->dest_cpu
== RCU_MIGRATION_MUST_SYNC
))
10981 need_full_sync
= 1;
10982 req
->dest_cpu
= RCU_MIGRATION_IDLE
;
10983 spin_unlock_irqrestore(&rq
->lock
, flags
);
10985 rcu_expedited_state
= RCU_EXPEDITED_STATE_IDLE
;
10986 synchronize_sched_expedited_count
++;
10987 mutex_unlock(&rcu_sched_expedited_mutex
);
10989 if (need_full_sync
)
10990 synchronize_sched();
10992 EXPORT_SYMBOL_GPL(synchronize_sched_expedited
);
10994 #endif /* #else #ifndef CONFIG_SMP */