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
29 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
32 #include <linux/module.h>
33 #include <linux/nmi.h>
34 #include <linux/init.h>
35 #include <linux/uaccess.h>
36 #include <linux/highmem.h>
37 #include <linux/smp_lock.h>
38 #include <asm/mmu_context.h>
39 #include <linux/interrupt.h>
40 #include <linux/capability.h>
41 #include <linux/completion.h>
42 #include <linux/kernel_stat.h>
43 #include <linux/debug_locks.h>
44 #include <linux/perf_event.h>
45 #include <linux/security.h>
46 #include <linux/notifier.h>
47 #include <linux/profile.h>
48 #include <linux/freezer.h>
49 #include <linux/vmalloc.h>
50 #include <linux/blkdev.h>
51 #include <linux/delay.h>
52 #include <linux/pid_namespace.h>
53 #include <linux/smp.h>
54 #include <linux/threads.h>
55 #include <linux/timer.h>
56 #include <linux/rcupdate.h>
57 #include <linux/cpu.h>
58 #include <linux/cpuset.h>
59 #include <linux/percpu.h>
60 #include <linux/kthread.h>
61 #include <linux/proc_fs.h>
62 #include <linux/seq_file.h>
63 #include <linux/sysctl.h>
64 #include <linux/syscalls.h>
65 #include <linux/times.h>
66 #include <linux/tsacct_kern.h>
67 #include <linux/kprobes.h>
68 #include <linux/delayacct.h>
69 #include <linux/unistd.h>
70 #include <linux/pagemap.h>
71 #include <linux/hrtimer.h>
72 #include <linux/tick.h>
73 #include <linux/debugfs.h>
74 #include <linux/ctype.h>
75 #include <linux/ftrace.h>
78 #include <asm/irq_regs.h>
80 #include "sched_cpupri.h"
82 #define CREATE_TRACE_POINTS
83 #include <trace/events/sched.h>
86 * Convert user-nice values [ -20 ... 0 ... 19 ]
87 * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
90 #define NICE_TO_PRIO(nice) (MAX_RT_PRIO + (nice) + 20)
91 #define PRIO_TO_NICE(prio) ((prio) - MAX_RT_PRIO - 20)
92 #define TASK_NICE(p) PRIO_TO_NICE((p)->static_prio)
95 * 'User priority' is the nice value converted to something we
96 * can work with better when scaling various scheduler parameters,
97 * it's a [ 0 ... 39 ] range.
99 #define USER_PRIO(p) ((p)-MAX_RT_PRIO)
100 #define TASK_USER_PRIO(p) USER_PRIO((p)->static_prio)
101 #define MAX_USER_PRIO (USER_PRIO(MAX_PRIO))
104 * Helpers for converting nanosecond timing to jiffy resolution
106 #define NS_TO_JIFFIES(TIME) ((unsigned long)(TIME) / (NSEC_PER_SEC / HZ))
108 #define NICE_0_LOAD SCHED_LOAD_SCALE
109 #define NICE_0_SHIFT SCHED_LOAD_SHIFT
112 * These are the 'tuning knobs' of the scheduler:
114 * default timeslice is 100 msecs (used only for SCHED_RR tasks).
115 * Timeslices get refilled after they expire.
117 #define DEF_TIMESLICE (100 * HZ / 1000)
120 * single value that denotes runtime == period, ie unlimited time.
122 #define RUNTIME_INF ((u64)~0ULL)
124 static inline int rt_policy(int policy
)
126 if (unlikely(policy
== SCHED_FIFO
|| policy
== SCHED_RR
))
131 static inline int task_has_rt_policy(struct task_struct
*p
)
133 return rt_policy(p
->policy
);
137 * This is the priority-queue data structure of the RT scheduling class:
139 struct rt_prio_array
{
140 DECLARE_BITMAP(bitmap
, MAX_RT_PRIO
+1); /* include 1 bit for delimiter */
141 struct list_head queue
[MAX_RT_PRIO
];
144 struct rt_bandwidth
{
145 /* nests inside the rq lock: */
146 raw_spinlock_t rt_runtime_lock
;
149 struct hrtimer rt_period_timer
;
152 static struct rt_bandwidth def_rt_bandwidth
;
154 static int do_sched_rt_period_timer(struct rt_bandwidth
*rt_b
, int overrun
);
156 static enum hrtimer_restart
sched_rt_period_timer(struct hrtimer
*timer
)
158 struct rt_bandwidth
*rt_b
=
159 container_of(timer
, struct rt_bandwidth
, rt_period_timer
);
165 now
= hrtimer_cb_get_time(timer
);
166 overrun
= hrtimer_forward(timer
, now
, rt_b
->rt_period
);
171 idle
= do_sched_rt_period_timer(rt_b
, overrun
);
174 return idle
? HRTIMER_NORESTART
: HRTIMER_RESTART
;
178 void init_rt_bandwidth(struct rt_bandwidth
*rt_b
, u64 period
, u64 runtime
)
180 rt_b
->rt_period
= ns_to_ktime(period
);
181 rt_b
->rt_runtime
= runtime
;
183 raw_spin_lock_init(&rt_b
->rt_runtime_lock
);
185 hrtimer_init(&rt_b
->rt_period_timer
,
186 CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
187 rt_b
->rt_period_timer
.function
= sched_rt_period_timer
;
190 static inline int rt_bandwidth_enabled(void)
192 return sysctl_sched_rt_runtime
>= 0;
195 static void start_rt_bandwidth(struct rt_bandwidth
*rt_b
)
199 if (!rt_bandwidth_enabled() || rt_b
->rt_runtime
== RUNTIME_INF
)
202 if (hrtimer_active(&rt_b
->rt_period_timer
))
205 raw_spin_lock(&rt_b
->rt_runtime_lock
);
210 if (hrtimer_active(&rt_b
->rt_period_timer
))
213 now
= hrtimer_cb_get_time(&rt_b
->rt_period_timer
);
214 hrtimer_forward(&rt_b
->rt_period_timer
, now
, rt_b
->rt_period
);
216 soft
= hrtimer_get_softexpires(&rt_b
->rt_period_timer
);
217 hard
= hrtimer_get_expires(&rt_b
->rt_period_timer
);
218 delta
= ktime_to_ns(ktime_sub(hard
, soft
));
219 __hrtimer_start_range_ns(&rt_b
->rt_period_timer
, soft
, delta
,
220 HRTIMER_MODE_ABS_PINNED
, 0);
222 raw_spin_unlock(&rt_b
->rt_runtime_lock
);
225 #ifdef CONFIG_RT_GROUP_SCHED
226 static void destroy_rt_bandwidth(struct rt_bandwidth
*rt_b
)
228 hrtimer_cancel(&rt_b
->rt_period_timer
);
233 * sched_domains_mutex serializes calls to arch_init_sched_domains,
234 * detach_destroy_domains and partition_sched_domains.
236 static DEFINE_MUTEX(sched_domains_mutex
);
238 #ifdef CONFIG_GROUP_SCHED
240 #include <linux/cgroup.h>
244 static LIST_HEAD(task_groups
);
246 /* task group related information */
248 #ifdef CONFIG_CGROUP_SCHED
249 struct cgroup_subsys_state css
;
252 #ifdef CONFIG_USER_SCHED
256 #ifdef CONFIG_FAIR_GROUP_SCHED
257 /* schedulable entities of this group on each cpu */
258 struct sched_entity
**se
;
259 /* runqueue "owned" by this group on each cpu */
260 struct cfs_rq
**cfs_rq
;
261 unsigned long shares
;
264 #ifdef CONFIG_RT_GROUP_SCHED
265 struct sched_rt_entity
**rt_se
;
266 struct rt_rq
**rt_rq
;
268 struct rt_bandwidth rt_bandwidth
;
272 struct list_head list
;
274 struct task_group
*parent
;
275 struct list_head siblings
;
276 struct list_head children
;
279 #ifdef CONFIG_USER_SCHED
281 /* Helper function to pass uid information to create_sched_user() */
282 void set_tg_uid(struct user_struct
*user
)
284 user
->tg
->uid
= user
->uid
;
289 * Every UID task group (including init_task_group aka UID-0) will
290 * be a child to this group.
292 struct task_group root_task_group
;
294 #ifdef CONFIG_FAIR_GROUP_SCHED
295 /* Default task group's sched entity on each cpu */
296 static DEFINE_PER_CPU(struct sched_entity
, init_sched_entity
);
297 /* Default task group's cfs_rq on each cpu */
298 static DEFINE_PER_CPU_SHARED_ALIGNED(struct cfs_rq
, init_tg_cfs_rq
);
299 #endif /* CONFIG_FAIR_GROUP_SCHED */
301 #ifdef CONFIG_RT_GROUP_SCHED
302 static DEFINE_PER_CPU(struct sched_rt_entity
, init_sched_rt_entity
);
303 static DEFINE_PER_CPU_SHARED_ALIGNED(struct rt_rq
, init_rt_rq_var
);
304 #endif /* CONFIG_RT_GROUP_SCHED */
305 #else /* !CONFIG_USER_SCHED */
306 #define root_task_group init_task_group
307 #endif /* CONFIG_USER_SCHED */
309 /* task_group_lock serializes add/remove of task groups and also changes to
310 * a task group's cpu shares.
312 static DEFINE_SPINLOCK(task_group_lock
);
314 #ifdef CONFIG_FAIR_GROUP_SCHED
317 static int root_task_group_empty(void)
319 return list_empty(&root_task_group
.children
);
323 #ifdef CONFIG_USER_SCHED
324 # define INIT_TASK_GROUP_LOAD (2*NICE_0_LOAD)
325 #else /* !CONFIG_USER_SCHED */
326 # define INIT_TASK_GROUP_LOAD NICE_0_LOAD
327 #endif /* CONFIG_USER_SCHED */
330 * A weight of 0 or 1 can cause arithmetics problems.
331 * A weight of a cfs_rq is the sum of weights of which entities
332 * are queued on this cfs_rq, so a weight of a entity should not be
333 * too large, so as the shares value of a task group.
334 * (The default weight is 1024 - so there's no practical
335 * limitation from this.)
338 #define MAX_SHARES (1UL << 18)
340 static int init_task_group_load
= INIT_TASK_GROUP_LOAD
;
343 /* Default task group.
344 * Every task in system belong to this group at bootup.
346 struct task_group init_task_group
;
348 /* return group to which a task belongs */
349 static inline struct task_group
*task_group(struct task_struct
*p
)
351 struct task_group
*tg
;
353 #ifdef CONFIG_USER_SCHED
355 tg
= __task_cred(p
)->user
->tg
;
357 #elif defined(CONFIG_CGROUP_SCHED)
358 tg
= container_of(task_subsys_state(p
, cpu_cgroup_subsys_id
),
359 struct task_group
, css
);
361 tg
= &init_task_group
;
366 /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
367 static inline void set_task_rq(struct task_struct
*p
, unsigned int cpu
)
369 #ifdef CONFIG_FAIR_GROUP_SCHED
370 p
->se
.cfs_rq
= task_group(p
)->cfs_rq
[cpu
];
371 p
->se
.parent
= task_group(p
)->se
[cpu
];
374 #ifdef CONFIG_RT_GROUP_SCHED
375 p
->rt
.rt_rq
= task_group(p
)->rt_rq
[cpu
];
376 p
->rt
.parent
= task_group(p
)->rt_se
[cpu
];
382 static inline void set_task_rq(struct task_struct
*p
, unsigned int cpu
) { }
383 static inline struct task_group
*task_group(struct task_struct
*p
)
388 #endif /* CONFIG_GROUP_SCHED */
390 /* CFS-related fields in a runqueue */
392 struct load_weight load
;
393 unsigned long nr_running
;
398 struct rb_root tasks_timeline
;
399 struct rb_node
*rb_leftmost
;
401 struct list_head tasks
;
402 struct list_head
*balance_iterator
;
405 * 'curr' points to currently running entity on this cfs_rq.
406 * It is set to NULL otherwise (i.e when none are currently running).
408 struct sched_entity
*curr
, *next
, *last
;
410 unsigned int nr_spread_over
;
412 #ifdef CONFIG_FAIR_GROUP_SCHED
413 struct rq
*rq
; /* cpu runqueue to which this cfs_rq is attached */
416 * leaf cfs_rqs are those that hold tasks (lowest schedulable entity in
417 * a hierarchy). Non-leaf lrqs hold other higher schedulable entities
418 * (like users, containers etc.)
420 * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This
421 * list is used during load balance.
423 struct list_head leaf_cfs_rq_list
;
424 struct task_group
*tg
; /* group that "owns" this runqueue */
428 * the part of load.weight contributed by tasks
430 unsigned long task_weight
;
433 * h_load = weight * f(tg)
435 * Where f(tg) is the recursive weight fraction assigned to
438 unsigned long h_load
;
441 * this cpu's part of tg->shares
443 unsigned long shares
;
446 * load.weight at the time we set shares
448 unsigned long rq_weight
;
453 /* Real-Time classes' related field in a runqueue: */
455 struct rt_prio_array active
;
456 unsigned long rt_nr_running
;
457 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
459 int curr
; /* highest queued rt task prio */
461 int next
; /* next highest */
466 unsigned long rt_nr_migratory
;
467 unsigned long rt_nr_total
;
469 struct plist_head pushable_tasks
;
474 /* Nests inside the rq lock: */
475 raw_spinlock_t rt_runtime_lock
;
477 #ifdef CONFIG_RT_GROUP_SCHED
478 unsigned long rt_nr_boosted
;
481 struct list_head leaf_rt_rq_list
;
482 struct task_group
*tg
;
483 struct sched_rt_entity
*rt_se
;
490 * We add the notion of a root-domain which will be used to define per-domain
491 * variables. Each exclusive cpuset essentially defines an island domain by
492 * fully partitioning the member cpus from any other cpuset. Whenever a new
493 * exclusive cpuset is created, we also create and attach a new root-domain
500 cpumask_var_t online
;
503 * The "RT overload" flag: it gets set if a CPU has more than
504 * one runnable RT task.
506 cpumask_var_t rto_mask
;
509 struct cpupri cpupri
;
514 * By default the system creates a single root-domain with all cpus as
515 * members (mimicking the global state we have today).
517 static struct root_domain def_root_domain
;
522 * This is the main, per-CPU runqueue data structure.
524 * Locking rule: those places that want to lock multiple runqueues
525 * (such as the load balancing or the thread migration code), lock
526 * acquire operations must be ordered by ascending &runqueue.
533 * nr_running and cpu_load should be in the same cacheline because
534 * remote CPUs use both these fields when doing load calculation.
536 unsigned long nr_running
;
537 #define CPU_LOAD_IDX_MAX 5
538 unsigned long cpu_load
[CPU_LOAD_IDX_MAX
];
540 unsigned char in_nohz_recently
;
542 /* capture load from *all* tasks on this cpu: */
543 struct load_weight load
;
544 unsigned long nr_load_updates
;
550 #ifdef CONFIG_FAIR_GROUP_SCHED
551 /* list of leaf cfs_rq on this cpu: */
552 struct list_head leaf_cfs_rq_list
;
554 #ifdef CONFIG_RT_GROUP_SCHED
555 struct list_head leaf_rt_rq_list
;
559 * This is part of a global counter where only the total sum
560 * over all CPUs matters. A task can increase this counter on
561 * one CPU and if it got migrated afterwards it may decrease
562 * it on another CPU. Always updated under the runqueue lock:
564 unsigned long nr_uninterruptible
;
566 struct task_struct
*curr
, *idle
;
567 unsigned long next_balance
;
568 struct mm_struct
*prev_mm
;
575 struct root_domain
*rd
;
576 struct sched_domain
*sd
;
578 unsigned char idle_at_tick
;
579 /* For active balancing */
583 /* cpu of this runqueue: */
587 unsigned long avg_load_per_task
;
589 struct task_struct
*migration_thread
;
590 struct list_head migration_queue
;
598 /* calc_load related fields */
599 unsigned long calc_load_update
;
600 long calc_load_active
;
602 #ifdef CONFIG_SCHED_HRTICK
604 int hrtick_csd_pending
;
605 struct call_single_data hrtick_csd
;
607 struct hrtimer hrtick_timer
;
610 #ifdef CONFIG_SCHEDSTATS
612 struct sched_info rq_sched_info
;
613 unsigned long long rq_cpu_time
;
614 /* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */
616 /* sys_sched_yield() stats */
617 unsigned int yld_count
;
619 /* schedule() stats */
620 unsigned int sched_switch
;
621 unsigned int sched_count
;
622 unsigned int sched_goidle
;
624 /* try_to_wake_up() stats */
625 unsigned int ttwu_count
;
626 unsigned int ttwu_local
;
629 unsigned int bkl_count
;
633 static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq
, runqueues
);
636 void check_preempt_curr(struct rq
*rq
, struct task_struct
*p
, int flags
)
638 rq
->curr
->sched_class
->check_preempt_curr(rq
, p
, flags
);
641 static inline int cpu_of(struct rq
*rq
)
651 * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
652 * See detach_destroy_domains: synchronize_sched for details.
654 * The domain tree of any CPU may only be accessed from within
655 * preempt-disabled sections.
657 #define for_each_domain(cpu, __sd) \
658 for (__sd = rcu_dereference(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent)
660 #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu)))
661 #define this_rq() (&__get_cpu_var(runqueues))
662 #define task_rq(p) cpu_rq(task_cpu(p))
663 #define cpu_curr(cpu) (cpu_rq(cpu)->curr)
664 #define raw_rq() (&__raw_get_cpu_var(runqueues))
666 inline void update_rq_clock(struct rq
*rq
)
668 rq
->clock
= sched_clock_cpu(cpu_of(rq
));
672 * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
674 #ifdef CONFIG_SCHED_DEBUG
675 # define const_debug __read_mostly
677 # define const_debug static const
682 * @cpu: the processor in question.
684 * Returns true if the current cpu runqueue is locked.
685 * This interface allows printk to be called with the runqueue lock
686 * held and know whether or not it is OK to wake up the klogd.
688 int runqueue_is_locked(int cpu
)
690 return raw_spin_is_locked(&cpu_rq(cpu
)->lock
);
694 * Debugging: various feature bits
697 #define SCHED_FEAT(name, enabled) \
698 __SCHED_FEAT_##name ,
701 #include "sched_features.h"
706 #define SCHED_FEAT(name, enabled) \
707 (1UL << __SCHED_FEAT_##name) * enabled |
709 const_debug
unsigned int sysctl_sched_features
=
710 #include "sched_features.h"
715 #ifdef CONFIG_SCHED_DEBUG
716 #define SCHED_FEAT(name, enabled) \
719 static __read_mostly
char *sched_feat_names
[] = {
720 #include "sched_features.h"
726 static int sched_feat_show(struct seq_file
*m
, void *v
)
730 for (i
= 0; sched_feat_names
[i
]; i
++) {
731 if (!(sysctl_sched_features
& (1UL << i
)))
733 seq_printf(m
, "%s ", sched_feat_names
[i
]);
741 sched_feat_write(struct file
*filp
, const char __user
*ubuf
,
742 size_t cnt
, loff_t
*ppos
)
752 if (copy_from_user(&buf
, ubuf
, cnt
))
757 if (strncmp(buf
, "NO_", 3) == 0) {
762 for (i
= 0; sched_feat_names
[i
]; i
++) {
763 int len
= strlen(sched_feat_names
[i
]);
765 if (strncmp(cmp
, sched_feat_names
[i
], len
) == 0) {
767 sysctl_sched_features
&= ~(1UL << i
);
769 sysctl_sched_features
|= (1UL << i
);
774 if (!sched_feat_names
[i
])
782 static int sched_feat_open(struct inode
*inode
, struct file
*filp
)
784 return single_open(filp
, sched_feat_show
, NULL
);
787 static const struct file_operations sched_feat_fops
= {
788 .open
= sched_feat_open
,
789 .write
= sched_feat_write
,
792 .release
= single_release
,
795 static __init
int sched_init_debug(void)
797 debugfs_create_file("sched_features", 0644, NULL
, NULL
,
802 late_initcall(sched_init_debug
);
806 #define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
809 * Number of tasks to iterate in a single balance run.
810 * Limited because this is done with IRQs disabled.
812 const_debug
unsigned int sysctl_sched_nr_migrate
= 32;
815 * ratelimit for updating the group shares.
818 unsigned int sysctl_sched_shares_ratelimit
= 250000;
819 unsigned int normalized_sysctl_sched_shares_ratelimit
= 250000;
822 * Inject some fuzzyness into changing the per-cpu group shares
823 * this avoids remote rq-locks at the expense of fairness.
826 unsigned int sysctl_sched_shares_thresh
= 4;
829 * period over which we average the RT time consumption, measured
834 const_debug
unsigned int sysctl_sched_time_avg
= MSEC_PER_SEC
;
837 * period over which we measure -rt task cpu usage in us.
840 unsigned int sysctl_sched_rt_period
= 1000000;
842 static __read_mostly
int scheduler_running
;
845 * part of the period that we allow rt tasks to run in us.
848 int sysctl_sched_rt_runtime
= 950000;
850 static inline u64
global_rt_period(void)
852 return (u64
)sysctl_sched_rt_period
* NSEC_PER_USEC
;
855 static inline u64
global_rt_runtime(void)
857 if (sysctl_sched_rt_runtime
< 0)
860 return (u64
)sysctl_sched_rt_runtime
* NSEC_PER_USEC
;
863 #ifndef prepare_arch_switch
864 # define prepare_arch_switch(next) do { } while (0)
866 #ifndef finish_arch_switch
867 # define finish_arch_switch(prev) do { } while (0)
870 static inline int task_current(struct rq
*rq
, struct task_struct
*p
)
872 return rq
->curr
== p
;
875 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
876 static inline int task_running(struct rq
*rq
, struct task_struct
*p
)
878 return task_current(rq
, p
);
881 static inline void prepare_lock_switch(struct rq
*rq
, struct task_struct
*next
)
885 static inline void finish_lock_switch(struct rq
*rq
, struct task_struct
*prev
)
887 #ifdef CONFIG_DEBUG_SPINLOCK
888 /* this is a valid case when another task releases the spinlock */
889 rq
->lock
.owner
= current
;
892 * If we are tracking spinlock dependencies then we have to
893 * fix up the runqueue lock - which gets 'carried over' from
896 spin_acquire(&rq
->lock
.dep_map
, 0, 0, _THIS_IP_
);
898 raw_spin_unlock_irq(&rq
->lock
);
901 #else /* __ARCH_WANT_UNLOCKED_CTXSW */
902 static inline int task_running(struct rq
*rq
, struct task_struct
*p
)
907 return task_current(rq
, p
);
911 static inline void prepare_lock_switch(struct rq
*rq
, struct task_struct
*next
)
915 * We can optimise this out completely for !SMP, because the
916 * SMP rebalancing from interrupt is the only thing that cares
921 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
922 raw_spin_unlock_irq(&rq
->lock
);
924 raw_spin_unlock(&rq
->lock
);
928 static inline void finish_lock_switch(struct rq
*rq
, struct task_struct
*prev
)
932 * After ->oncpu is cleared, the task can be moved to a different CPU.
933 * We must ensure this doesn't happen until the switch is completely
939 #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW
943 #endif /* __ARCH_WANT_UNLOCKED_CTXSW */
946 * __task_rq_lock - lock the runqueue a given task resides on.
947 * Must be called interrupts disabled.
949 static inline struct rq
*__task_rq_lock(struct task_struct
*p
)
953 struct rq
*rq
= task_rq(p
);
954 raw_spin_lock(&rq
->lock
);
955 if (likely(rq
== task_rq(p
)))
957 raw_spin_unlock(&rq
->lock
);
962 * task_rq_lock - lock the runqueue a given task resides on and disable
963 * interrupts. Note the ordering: we can safely lookup the task_rq without
964 * explicitly disabling preemption.
966 static struct rq
*task_rq_lock(struct task_struct
*p
, unsigned long *flags
)
972 local_irq_save(*flags
);
974 raw_spin_lock(&rq
->lock
);
975 if (likely(rq
== task_rq(p
)))
977 raw_spin_unlock_irqrestore(&rq
->lock
, *flags
);
981 void task_rq_unlock_wait(struct task_struct
*p
)
983 struct rq
*rq
= task_rq(p
);
985 smp_mb(); /* spin-unlock-wait is not a full memory barrier */
986 raw_spin_unlock_wait(&rq
->lock
);
989 static void __task_rq_unlock(struct rq
*rq
)
992 raw_spin_unlock(&rq
->lock
);
995 static inline void task_rq_unlock(struct rq
*rq
, unsigned long *flags
)
998 raw_spin_unlock_irqrestore(&rq
->lock
, *flags
);
1002 * this_rq_lock - lock this runqueue and disable interrupts.
1004 static struct rq
*this_rq_lock(void)
1005 __acquires(rq
->lock
)
1009 local_irq_disable();
1011 raw_spin_lock(&rq
->lock
);
1016 #ifdef CONFIG_SCHED_HRTICK
1018 * Use HR-timers to deliver accurate preemption points.
1020 * Its all a bit involved since we cannot program an hrt while holding the
1021 * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
1024 * When we get rescheduled we reprogram the hrtick_timer outside of the
1030 * - enabled by features
1031 * - hrtimer is actually high res
1033 static inline int hrtick_enabled(struct rq
*rq
)
1035 if (!sched_feat(HRTICK
))
1037 if (!cpu_active(cpu_of(rq
)))
1039 return hrtimer_is_hres_active(&rq
->hrtick_timer
);
1042 static void hrtick_clear(struct rq
*rq
)
1044 if (hrtimer_active(&rq
->hrtick_timer
))
1045 hrtimer_cancel(&rq
->hrtick_timer
);
1049 * High-resolution timer tick.
1050 * Runs from hardirq context with interrupts disabled.
1052 static enum hrtimer_restart
hrtick(struct hrtimer
*timer
)
1054 struct rq
*rq
= container_of(timer
, struct rq
, hrtick_timer
);
1056 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
1058 raw_spin_lock(&rq
->lock
);
1059 update_rq_clock(rq
);
1060 rq
->curr
->sched_class
->task_tick(rq
, rq
->curr
, 1);
1061 raw_spin_unlock(&rq
->lock
);
1063 return HRTIMER_NORESTART
;
1068 * called from hardirq (IPI) context
1070 static void __hrtick_start(void *arg
)
1072 struct rq
*rq
= arg
;
1074 raw_spin_lock(&rq
->lock
);
1075 hrtimer_restart(&rq
->hrtick_timer
);
1076 rq
->hrtick_csd_pending
= 0;
1077 raw_spin_unlock(&rq
->lock
);
1081 * Called to set the hrtick timer state.
1083 * called with rq->lock held and irqs disabled
1085 static void hrtick_start(struct rq
*rq
, u64 delay
)
1087 struct hrtimer
*timer
= &rq
->hrtick_timer
;
1088 ktime_t time
= ktime_add_ns(timer
->base
->get_time(), delay
);
1090 hrtimer_set_expires(timer
, time
);
1092 if (rq
== this_rq()) {
1093 hrtimer_restart(timer
);
1094 } else if (!rq
->hrtick_csd_pending
) {
1095 __smp_call_function_single(cpu_of(rq
), &rq
->hrtick_csd
, 0);
1096 rq
->hrtick_csd_pending
= 1;
1101 hotplug_hrtick(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
1103 int cpu
= (int)(long)hcpu
;
1106 case CPU_UP_CANCELED
:
1107 case CPU_UP_CANCELED_FROZEN
:
1108 case CPU_DOWN_PREPARE
:
1109 case CPU_DOWN_PREPARE_FROZEN
:
1111 case CPU_DEAD_FROZEN
:
1112 hrtick_clear(cpu_rq(cpu
));
1119 static __init
void init_hrtick(void)
1121 hotcpu_notifier(hotplug_hrtick
, 0);
1125 * Called to set the hrtick timer state.
1127 * called with rq->lock held and irqs disabled
1129 static void hrtick_start(struct rq
*rq
, u64 delay
)
1131 __hrtimer_start_range_ns(&rq
->hrtick_timer
, ns_to_ktime(delay
), 0,
1132 HRTIMER_MODE_REL_PINNED
, 0);
1135 static inline void init_hrtick(void)
1138 #endif /* CONFIG_SMP */
1140 static void init_rq_hrtick(struct rq
*rq
)
1143 rq
->hrtick_csd_pending
= 0;
1145 rq
->hrtick_csd
.flags
= 0;
1146 rq
->hrtick_csd
.func
= __hrtick_start
;
1147 rq
->hrtick_csd
.info
= rq
;
1150 hrtimer_init(&rq
->hrtick_timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
1151 rq
->hrtick_timer
.function
= hrtick
;
1153 #else /* CONFIG_SCHED_HRTICK */
1154 static inline void hrtick_clear(struct rq
*rq
)
1158 static inline void init_rq_hrtick(struct rq
*rq
)
1162 static inline void init_hrtick(void)
1165 #endif /* CONFIG_SCHED_HRTICK */
1168 * resched_task - mark a task 'to be rescheduled now'.
1170 * On UP this means the setting of the need_resched flag, on SMP it
1171 * might also involve a cross-CPU call to trigger the scheduler on
1176 #ifndef tsk_is_polling
1177 #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
1180 static void resched_task(struct task_struct
*p
)
1184 assert_raw_spin_locked(&task_rq(p
)->lock
);
1186 if (test_tsk_need_resched(p
))
1189 set_tsk_need_resched(p
);
1192 if (cpu
== smp_processor_id())
1195 /* NEED_RESCHED must be visible before we test polling */
1197 if (!tsk_is_polling(p
))
1198 smp_send_reschedule(cpu
);
1201 static void resched_cpu(int cpu
)
1203 struct rq
*rq
= cpu_rq(cpu
);
1204 unsigned long flags
;
1206 if (!raw_spin_trylock_irqsave(&rq
->lock
, flags
))
1208 resched_task(cpu_curr(cpu
));
1209 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
1214 * When add_timer_on() enqueues a timer into the timer wheel of an
1215 * idle CPU then this timer might expire before the next timer event
1216 * which is scheduled to wake up that CPU. In case of a completely
1217 * idle system the next event might even be infinite time into the
1218 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
1219 * leaves the inner idle loop so the newly added timer is taken into
1220 * account when the CPU goes back to idle and evaluates the timer
1221 * wheel for the next timer event.
1223 void wake_up_idle_cpu(int cpu
)
1225 struct rq
*rq
= cpu_rq(cpu
);
1227 if (cpu
== smp_processor_id())
1231 * This is safe, as this function is called with the timer
1232 * wheel base lock of (cpu) held. When the CPU is on the way
1233 * to idle and has not yet set rq->curr to idle then it will
1234 * be serialized on the timer wheel base lock and take the new
1235 * timer into account automatically.
1237 if (rq
->curr
!= rq
->idle
)
1241 * We can set TIF_RESCHED on the idle task of the other CPU
1242 * lockless. The worst case is that the other CPU runs the
1243 * idle task through an additional NOOP schedule()
1245 set_tsk_need_resched(rq
->idle
);
1247 /* NEED_RESCHED must be visible before we test polling */
1249 if (!tsk_is_polling(rq
->idle
))
1250 smp_send_reschedule(cpu
);
1252 #endif /* CONFIG_NO_HZ */
1254 static u64
sched_avg_period(void)
1256 return (u64
)sysctl_sched_time_avg
* NSEC_PER_MSEC
/ 2;
1259 static void sched_avg_update(struct rq
*rq
)
1261 s64 period
= sched_avg_period();
1263 while ((s64
)(rq
->clock
- rq
->age_stamp
) > period
) {
1264 rq
->age_stamp
+= period
;
1269 static void sched_rt_avg_update(struct rq
*rq
, u64 rt_delta
)
1271 rq
->rt_avg
+= rt_delta
;
1272 sched_avg_update(rq
);
1275 #else /* !CONFIG_SMP */
1276 static void resched_task(struct task_struct
*p
)
1278 assert_raw_spin_locked(&task_rq(p
)->lock
);
1279 set_tsk_need_resched(p
);
1282 static void sched_rt_avg_update(struct rq
*rq
, u64 rt_delta
)
1285 #endif /* CONFIG_SMP */
1287 #if BITS_PER_LONG == 32
1288 # define WMULT_CONST (~0UL)
1290 # define WMULT_CONST (1UL << 32)
1293 #define WMULT_SHIFT 32
1296 * Shift right and round:
1298 #define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y))
1301 * delta *= weight / lw
1303 static unsigned long
1304 calc_delta_mine(unsigned long delta_exec
, unsigned long weight
,
1305 struct load_weight
*lw
)
1309 if (!lw
->inv_weight
) {
1310 if (BITS_PER_LONG
> 32 && unlikely(lw
->weight
>= WMULT_CONST
))
1313 lw
->inv_weight
= 1 + (WMULT_CONST
-lw
->weight
/2)
1317 tmp
= (u64
)delta_exec
* weight
;
1319 * Check whether we'd overflow the 64-bit multiplication:
1321 if (unlikely(tmp
> WMULT_CONST
))
1322 tmp
= SRR(SRR(tmp
, WMULT_SHIFT
/2) * lw
->inv_weight
,
1325 tmp
= SRR(tmp
* lw
->inv_weight
, WMULT_SHIFT
);
1327 return (unsigned long)min(tmp
, (u64
)(unsigned long)LONG_MAX
);
1330 static inline void update_load_add(struct load_weight
*lw
, unsigned long inc
)
1336 static inline void update_load_sub(struct load_weight
*lw
, unsigned long dec
)
1343 * To aid in avoiding the subversion of "niceness" due to uneven distribution
1344 * of tasks with abnormal "nice" values across CPUs the contribution that
1345 * each task makes to its run queue's load is weighted according to its
1346 * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
1347 * scaled version of the new time slice allocation that they receive on time
1351 #define WEIGHT_IDLEPRIO 3
1352 #define WMULT_IDLEPRIO 1431655765
1355 * Nice levels are multiplicative, with a gentle 10% change for every
1356 * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
1357 * nice 1, it will get ~10% less CPU time than another CPU-bound task
1358 * that remained on nice 0.
1360 * The "10% effect" is relative and cumulative: from _any_ nice level,
1361 * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
1362 * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
1363 * If a task goes up by ~10% and another task goes down by ~10% then
1364 * the relative distance between them is ~25%.)
1366 static const int prio_to_weight
[40] = {
1367 /* -20 */ 88761, 71755, 56483, 46273, 36291,
1368 /* -15 */ 29154, 23254, 18705, 14949, 11916,
1369 /* -10 */ 9548, 7620, 6100, 4904, 3906,
1370 /* -5 */ 3121, 2501, 1991, 1586, 1277,
1371 /* 0 */ 1024, 820, 655, 526, 423,
1372 /* 5 */ 335, 272, 215, 172, 137,
1373 /* 10 */ 110, 87, 70, 56, 45,
1374 /* 15 */ 36, 29, 23, 18, 15,
1378 * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated.
1380 * In cases where the weight does not change often, we can use the
1381 * precalculated inverse to speed up arithmetics by turning divisions
1382 * into multiplications:
1384 static const u32 prio_to_wmult
[40] = {
1385 /* -20 */ 48388, 59856, 76040, 92818, 118348,
1386 /* -15 */ 147320, 184698, 229616, 287308, 360437,
1387 /* -10 */ 449829, 563644, 704093, 875809, 1099582,
1388 /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326,
1389 /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587,
1390 /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126,
1391 /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717,
1392 /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
1395 static void activate_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
);
1398 * runqueue iterator, to support SMP load-balancing between different
1399 * scheduling classes, without having to expose their internal data
1400 * structures to the load-balancing proper:
1402 struct rq_iterator
{
1404 struct task_struct
*(*start
)(void *);
1405 struct task_struct
*(*next
)(void *);
1409 static unsigned long
1410 balance_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
1411 unsigned long max_load_move
, struct sched_domain
*sd
,
1412 enum cpu_idle_type idle
, int *all_pinned
,
1413 int *this_best_prio
, struct rq_iterator
*iterator
);
1416 iter_move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
1417 struct sched_domain
*sd
, enum cpu_idle_type idle
,
1418 struct rq_iterator
*iterator
);
1421 /* Time spent by the tasks of the cpu accounting group executing in ... */
1422 enum cpuacct_stat_index
{
1423 CPUACCT_STAT_USER
, /* ... user mode */
1424 CPUACCT_STAT_SYSTEM
, /* ... kernel mode */
1426 CPUACCT_STAT_NSTATS
,
1429 #ifdef CONFIG_CGROUP_CPUACCT
1430 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
);
1431 static void cpuacct_update_stats(struct task_struct
*tsk
,
1432 enum cpuacct_stat_index idx
, cputime_t val
);
1434 static inline void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
) {}
1435 static inline void cpuacct_update_stats(struct task_struct
*tsk
,
1436 enum cpuacct_stat_index idx
, cputime_t val
) {}
1439 static inline void inc_cpu_load(struct rq
*rq
, unsigned long load
)
1441 update_load_add(&rq
->load
, load
);
1444 static inline void dec_cpu_load(struct rq
*rq
, unsigned long load
)
1446 update_load_sub(&rq
->load
, load
);
1449 #if (defined(CONFIG_SMP) && defined(CONFIG_FAIR_GROUP_SCHED)) || defined(CONFIG_RT_GROUP_SCHED)
1450 typedef int (*tg_visitor
)(struct task_group
*, void *);
1453 * Iterate the full tree, calling @down when first entering a node and @up when
1454 * leaving it for the final time.
1456 static int walk_tg_tree(tg_visitor down
, tg_visitor up
, void *data
)
1458 struct task_group
*parent
, *child
;
1462 parent
= &root_task_group
;
1464 ret
= (*down
)(parent
, data
);
1467 list_for_each_entry_rcu(child
, &parent
->children
, siblings
) {
1474 ret
= (*up
)(parent
, data
);
1479 parent
= parent
->parent
;
1488 static int tg_nop(struct task_group
*tg
, void *data
)
1495 /* Used instead of source_load when we know the type == 0 */
1496 static unsigned long weighted_cpuload(const int cpu
)
1498 return cpu_rq(cpu
)->load
.weight
;
1502 * Return a low guess at the load of a migration-source cpu weighted
1503 * according to the scheduling class and "nice" value.
1505 * We want to under-estimate the load of migration sources, to
1506 * balance conservatively.
1508 static unsigned long source_load(int cpu
, int type
)
1510 struct rq
*rq
= cpu_rq(cpu
);
1511 unsigned long total
= weighted_cpuload(cpu
);
1513 if (type
== 0 || !sched_feat(LB_BIAS
))
1516 return min(rq
->cpu_load
[type
-1], total
);
1520 * Return a high guess at the load of a migration-target cpu weighted
1521 * according to the scheduling class and "nice" value.
1523 static unsigned long target_load(int cpu
, int type
)
1525 struct rq
*rq
= cpu_rq(cpu
);
1526 unsigned long total
= weighted_cpuload(cpu
);
1528 if (type
== 0 || !sched_feat(LB_BIAS
))
1531 return max(rq
->cpu_load
[type
-1], total
);
1534 static struct sched_group
*group_of(int cpu
)
1536 struct sched_domain
*sd
= rcu_dereference(cpu_rq(cpu
)->sd
);
1544 static unsigned long power_of(int cpu
)
1546 struct sched_group
*group
= group_of(cpu
);
1549 return SCHED_LOAD_SCALE
;
1551 return group
->cpu_power
;
1554 static int task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
);
1556 static unsigned long cpu_avg_load_per_task(int cpu
)
1558 struct rq
*rq
= cpu_rq(cpu
);
1559 unsigned long nr_running
= ACCESS_ONCE(rq
->nr_running
);
1562 rq
->avg_load_per_task
= rq
->load
.weight
/ nr_running
;
1564 rq
->avg_load_per_task
= 0;
1566 return rq
->avg_load_per_task
;
1569 #ifdef CONFIG_FAIR_GROUP_SCHED
1571 static __read_mostly
unsigned long *update_shares_data
;
1573 static void __set_se_shares(struct sched_entity
*se
, unsigned long shares
);
1576 * Calculate and set the cpu's group shares.
1578 static void update_group_shares_cpu(struct task_group
*tg
, int cpu
,
1579 unsigned long sd_shares
,
1580 unsigned long sd_rq_weight
,
1581 unsigned long *usd_rq_weight
)
1583 unsigned long shares
, rq_weight
;
1586 rq_weight
= usd_rq_weight
[cpu
];
1589 rq_weight
= NICE_0_LOAD
;
1593 * \Sum_j shares_j * rq_weight_i
1594 * shares_i = -----------------------------
1595 * \Sum_j rq_weight_j
1597 shares
= (sd_shares
* rq_weight
) / sd_rq_weight
;
1598 shares
= clamp_t(unsigned long, shares
, MIN_SHARES
, MAX_SHARES
);
1600 if (abs(shares
- tg
->se
[cpu
]->load
.weight
) >
1601 sysctl_sched_shares_thresh
) {
1602 struct rq
*rq
= cpu_rq(cpu
);
1603 unsigned long flags
;
1605 raw_spin_lock_irqsave(&rq
->lock
, flags
);
1606 tg
->cfs_rq
[cpu
]->rq_weight
= boost
? 0 : rq_weight
;
1607 tg
->cfs_rq
[cpu
]->shares
= boost
? 0 : shares
;
1608 __set_se_shares(tg
->se
[cpu
], shares
);
1609 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
1614 * Re-compute the task group their per cpu shares over the given domain.
1615 * This needs to be done in a bottom-up fashion because the rq weight of a
1616 * parent group depends on the shares of its child groups.
1618 static int tg_shares_up(struct task_group
*tg
, void *data
)
1620 unsigned long weight
, rq_weight
= 0, sum_weight
= 0, shares
= 0;
1621 unsigned long *usd_rq_weight
;
1622 struct sched_domain
*sd
= data
;
1623 unsigned long flags
;
1629 local_irq_save(flags
);
1630 usd_rq_weight
= per_cpu_ptr(update_shares_data
, smp_processor_id());
1632 for_each_cpu(i
, sched_domain_span(sd
)) {
1633 weight
= tg
->cfs_rq
[i
]->load
.weight
;
1634 usd_rq_weight
[i
] = weight
;
1636 rq_weight
+= weight
;
1638 * If there are currently no tasks on the cpu pretend there
1639 * is one of average load so that when a new task gets to
1640 * run here it will not get delayed by group starvation.
1643 weight
= NICE_0_LOAD
;
1645 sum_weight
+= weight
;
1646 shares
+= tg
->cfs_rq
[i
]->shares
;
1650 rq_weight
= sum_weight
;
1652 if ((!shares
&& rq_weight
) || shares
> tg
->shares
)
1653 shares
= tg
->shares
;
1655 if (!sd
->parent
|| !(sd
->parent
->flags
& SD_LOAD_BALANCE
))
1656 shares
= tg
->shares
;
1658 for_each_cpu(i
, sched_domain_span(sd
))
1659 update_group_shares_cpu(tg
, i
, shares
, rq_weight
, usd_rq_weight
);
1661 local_irq_restore(flags
);
1667 * Compute the cpu's hierarchical load factor for each task group.
1668 * This needs to be done in a top-down fashion because the load of a child
1669 * group is a fraction of its parents load.
1671 static int tg_load_down(struct task_group
*tg
, void *data
)
1674 long cpu
= (long)data
;
1677 load
= cpu_rq(cpu
)->load
.weight
;
1679 load
= tg
->parent
->cfs_rq
[cpu
]->h_load
;
1680 load
*= tg
->cfs_rq
[cpu
]->shares
;
1681 load
/= tg
->parent
->cfs_rq
[cpu
]->load
.weight
+ 1;
1684 tg
->cfs_rq
[cpu
]->h_load
= load
;
1689 static void update_shares(struct sched_domain
*sd
)
1694 if (root_task_group_empty())
1697 now
= cpu_clock(raw_smp_processor_id());
1698 elapsed
= now
- sd
->last_update
;
1700 if (elapsed
>= (s64
)(u64
)sysctl_sched_shares_ratelimit
) {
1701 sd
->last_update
= now
;
1702 walk_tg_tree(tg_nop
, tg_shares_up
, sd
);
1706 static void update_shares_locked(struct rq
*rq
, struct sched_domain
*sd
)
1708 if (root_task_group_empty())
1711 raw_spin_unlock(&rq
->lock
);
1713 raw_spin_lock(&rq
->lock
);
1716 static void update_h_load(long cpu
)
1718 if (root_task_group_empty())
1721 walk_tg_tree(tg_load_down
, tg_nop
, (void *)cpu
);
1726 static inline void update_shares(struct sched_domain
*sd
)
1730 static inline void update_shares_locked(struct rq
*rq
, struct sched_domain
*sd
)
1736 #ifdef CONFIG_PREEMPT
1738 static void double_rq_lock(struct rq
*rq1
, struct rq
*rq2
);
1741 * fair double_lock_balance: Safely acquires both rq->locks in a fair
1742 * way at the expense of forcing extra atomic operations in all
1743 * invocations. This assures that the double_lock is acquired using the
1744 * same underlying policy as the spinlock_t on this architecture, which
1745 * reduces latency compared to the unfair variant below. However, it
1746 * also adds more overhead and therefore may reduce throughput.
1748 static inline int _double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1749 __releases(this_rq
->lock
)
1750 __acquires(busiest
->lock
)
1751 __acquires(this_rq
->lock
)
1753 raw_spin_unlock(&this_rq
->lock
);
1754 double_rq_lock(this_rq
, busiest
);
1761 * Unfair double_lock_balance: Optimizes throughput at the expense of
1762 * latency by eliminating extra atomic operations when the locks are
1763 * already in proper order on entry. This favors lower cpu-ids and will
1764 * grant the double lock to lower cpus over higher ids under contention,
1765 * regardless of entry order into the function.
1767 static int _double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1768 __releases(this_rq
->lock
)
1769 __acquires(busiest
->lock
)
1770 __acquires(this_rq
->lock
)
1774 if (unlikely(!raw_spin_trylock(&busiest
->lock
))) {
1775 if (busiest
< this_rq
) {
1776 raw_spin_unlock(&this_rq
->lock
);
1777 raw_spin_lock(&busiest
->lock
);
1778 raw_spin_lock_nested(&this_rq
->lock
,
1779 SINGLE_DEPTH_NESTING
);
1782 raw_spin_lock_nested(&busiest
->lock
,
1783 SINGLE_DEPTH_NESTING
);
1788 #endif /* CONFIG_PREEMPT */
1791 * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
1793 static int double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1795 if (unlikely(!irqs_disabled())) {
1796 /* printk() doesn't work good under rq->lock */
1797 raw_spin_unlock(&this_rq
->lock
);
1801 return _double_lock_balance(this_rq
, busiest
);
1804 static inline void double_unlock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1805 __releases(busiest
->lock
)
1807 raw_spin_unlock(&busiest
->lock
);
1808 lock_set_subclass(&this_rq
->lock
.dep_map
, 0, _RET_IP_
);
1812 #ifdef CONFIG_FAIR_GROUP_SCHED
1813 static void cfs_rq_set_shares(struct cfs_rq
*cfs_rq
, unsigned long shares
)
1816 cfs_rq
->shares
= shares
;
1821 static void calc_load_account_active(struct rq
*this_rq
);
1822 static void update_sysctl(void);
1823 static int get_update_sysctl_factor(void);
1825 static inline void __set_task_cpu(struct task_struct
*p
, unsigned int cpu
)
1827 set_task_rq(p
, cpu
);
1830 * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be
1831 * successfuly executed on another CPU. We must ensure that updates of
1832 * per-task data have been completed by this moment.
1835 task_thread_info(p
)->cpu
= cpu
;
1839 #include "sched_stats.h"
1840 #include "sched_idletask.c"
1841 #include "sched_fair.c"
1842 #include "sched_rt.c"
1843 #ifdef CONFIG_SCHED_DEBUG
1844 # include "sched_debug.c"
1847 #define sched_class_highest (&rt_sched_class)
1848 #define for_each_class(class) \
1849 for (class = sched_class_highest; class; class = class->next)
1851 static void inc_nr_running(struct rq
*rq
)
1856 static void dec_nr_running(struct rq
*rq
)
1861 static void set_load_weight(struct task_struct
*p
)
1863 if (task_has_rt_policy(p
)) {
1864 p
->se
.load
.weight
= prio_to_weight
[0] * 2;
1865 p
->se
.load
.inv_weight
= prio_to_wmult
[0] >> 1;
1870 * SCHED_IDLE tasks get minimal weight:
1872 if (p
->policy
== SCHED_IDLE
) {
1873 p
->se
.load
.weight
= WEIGHT_IDLEPRIO
;
1874 p
->se
.load
.inv_weight
= WMULT_IDLEPRIO
;
1878 p
->se
.load
.weight
= prio_to_weight
[p
->static_prio
- MAX_RT_PRIO
];
1879 p
->se
.load
.inv_weight
= prio_to_wmult
[p
->static_prio
- MAX_RT_PRIO
];
1882 static void update_avg(u64
*avg
, u64 sample
)
1884 s64 diff
= sample
- *avg
;
1888 static void enqueue_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
)
1891 p
->se
.start_runtime
= p
->se
.sum_exec_runtime
;
1893 sched_info_queued(p
);
1894 p
->sched_class
->enqueue_task(rq
, p
, wakeup
);
1898 static void dequeue_task(struct rq
*rq
, struct task_struct
*p
, int sleep
)
1901 if (p
->se
.last_wakeup
) {
1902 update_avg(&p
->se
.avg_overlap
,
1903 p
->se
.sum_exec_runtime
- p
->se
.last_wakeup
);
1904 p
->se
.last_wakeup
= 0;
1906 update_avg(&p
->se
.avg_wakeup
,
1907 sysctl_sched_wakeup_granularity
);
1911 sched_info_dequeued(p
);
1912 p
->sched_class
->dequeue_task(rq
, p
, sleep
);
1917 * __normal_prio - return the priority that is based on the static prio
1919 static inline int __normal_prio(struct task_struct
*p
)
1921 return p
->static_prio
;
1925 * Calculate the expected normal priority: i.e. priority
1926 * without taking RT-inheritance into account. Might be
1927 * boosted by interactivity modifiers. Changes upon fork,
1928 * setprio syscalls, and whenever the interactivity
1929 * estimator recalculates.
1931 static inline int normal_prio(struct task_struct
*p
)
1935 if (task_has_rt_policy(p
))
1936 prio
= MAX_RT_PRIO
-1 - p
->rt_priority
;
1938 prio
= __normal_prio(p
);
1943 * Calculate the current priority, i.e. the priority
1944 * taken into account by the scheduler. This value might
1945 * be boosted by RT tasks, or might be boosted by
1946 * interactivity modifiers. Will be RT if the task got
1947 * RT-boosted. If not then it returns p->normal_prio.
1949 static int effective_prio(struct task_struct
*p
)
1951 p
->normal_prio
= normal_prio(p
);
1953 * If we are RT tasks or we were boosted to RT priority,
1954 * keep the priority unchanged. Otherwise, update priority
1955 * to the normal priority:
1957 if (!rt_prio(p
->prio
))
1958 return p
->normal_prio
;
1963 * activate_task - move a task to the runqueue.
1965 static void activate_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
)
1967 if (task_contributes_to_load(p
))
1968 rq
->nr_uninterruptible
--;
1970 enqueue_task(rq
, p
, wakeup
);
1975 * deactivate_task - remove a task from the runqueue.
1977 static void deactivate_task(struct rq
*rq
, struct task_struct
*p
, int sleep
)
1979 if (task_contributes_to_load(p
))
1980 rq
->nr_uninterruptible
++;
1982 dequeue_task(rq
, p
, sleep
);
1987 * task_curr - is this task currently executing on a CPU?
1988 * @p: the task in question.
1990 inline int task_curr(const struct task_struct
*p
)
1992 return cpu_curr(task_cpu(p
)) == p
;
1995 static inline void check_class_changed(struct rq
*rq
, struct task_struct
*p
,
1996 const struct sched_class
*prev_class
,
1997 int oldprio
, int running
)
1999 if (prev_class
!= p
->sched_class
) {
2000 if (prev_class
->switched_from
)
2001 prev_class
->switched_from(rq
, p
, running
);
2002 p
->sched_class
->switched_to(rq
, p
, running
);
2004 p
->sched_class
->prio_changed(rq
, p
, oldprio
, running
);
2008 * kthread_bind - bind a just-created kthread to a cpu.
2009 * @p: thread created by kthread_create().
2010 * @cpu: cpu (might not be online, must be possible) for @k to run on.
2012 * Description: This function is equivalent to set_cpus_allowed(),
2013 * except that @cpu doesn't need to be online, and the thread must be
2014 * stopped (i.e., just returned from kthread_create()).
2016 * Function lives here instead of kthread.c because it messes with
2017 * scheduler internals which require locking.
2019 void kthread_bind(struct task_struct
*p
, unsigned int cpu
)
2021 struct rq
*rq
= cpu_rq(cpu
);
2022 unsigned long flags
;
2024 /* Must have done schedule() in kthread() before we set_task_cpu */
2025 if (!wait_task_inactive(p
, TASK_UNINTERRUPTIBLE
)) {
2030 raw_spin_lock_irqsave(&rq
->lock
, flags
);
2031 update_rq_clock(rq
);
2032 set_task_cpu(p
, cpu
);
2033 p
->cpus_allowed
= cpumask_of_cpu(cpu
);
2034 p
->rt
.nr_cpus_allowed
= 1;
2035 p
->flags
|= PF_THREAD_BOUND
;
2036 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
2038 EXPORT_SYMBOL(kthread_bind
);
2042 * Is this task likely cache-hot:
2045 task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
)
2049 if (p
->sched_class
!= &fair_sched_class
)
2053 * Buddy candidates are cache hot:
2055 if (sched_feat(CACHE_HOT_BUDDY
) && this_rq()->nr_running
&&
2056 (&p
->se
== cfs_rq_of(&p
->se
)->next
||
2057 &p
->se
== cfs_rq_of(&p
->se
)->last
))
2060 if (sysctl_sched_migration_cost
== -1)
2062 if (sysctl_sched_migration_cost
== 0)
2065 delta
= now
- p
->se
.exec_start
;
2067 return delta
< (s64
)sysctl_sched_migration_cost
;
2071 void set_task_cpu(struct task_struct
*p
, unsigned int new_cpu
)
2073 int old_cpu
= task_cpu(p
);
2074 struct cfs_rq
*old_cfsrq
= task_cfs_rq(p
),
2075 *new_cfsrq
= cpu_cfs_rq(old_cfsrq
, new_cpu
);
2077 trace_sched_migrate_task(p
, new_cpu
);
2079 if (old_cpu
!= new_cpu
) {
2080 p
->se
.nr_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;
2524 p
->se
.nr_wakeups
= 0;
2525 p
->se
.nr_wakeups_sync
= 0;
2526 p
->se
.nr_wakeups_migrate
= 0;
2527 p
->se
.nr_wakeups_local
= 0;
2528 p
->se
.nr_wakeups_remote
= 0;
2529 p
->se
.nr_wakeups_affine
= 0;
2530 p
->se
.nr_wakeups_affine_attempts
= 0;
2531 p
->se
.nr_wakeups_passive
= 0;
2532 p
->se
.nr_wakeups_idle
= 0;
2536 INIT_LIST_HEAD(&p
->rt
.run_list
);
2538 INIT_LIST_HEAD(&p
->se
.group_node
);
2540 #ifdef CONFIG_PREEMPT_NOTIFIERS
2541 INIT_HLIST_HEAD(&p
->preempt_notifiers
);
2546 * fork()/clone()-time setup:
2548 void sched_fork(struct task_struct
*p
, int clone_flags
)
2550 int cpu
= get_cpu();
2554 * We mark the process as waking here. This guarantees that
2555 * nobody will actually run it, and a signal or other external
2556 * event cannot wake it up and insert it on the runqueue either.
2558 p
->state
= TASK_WAKING
;
2561 * Revert to default priority/policy on fork if requested.
2563 if (unlikely(p
->sched_reset_on_fork
)) {
2564 if (p
->policy
== SCHED_FIFO
|| p
->policy
== SCHED_RR
) {
2565 p
->policy
= SCHED_NORMAL
;
2566 p
->normal_prio
= p
->static_prio
;
2569 if (PRIO_TO_NICE(p
->static_prio
) < 0) {
2570 p
->static_prio
= NICE_TO_PRIO(0);
2571 p
->normal_prio
= p
->static_prio
;
2576 * We don't need the reset flag anymore after the fork. It has
2577 * fulfilled its duty:
2579 p
->sched_reset_on_fork
= 0;
2583 * Make sure we do not leak PI boosting priority to the child.
2585 p
->prio
= current
->normal_prio
;
2587 if (!rt_prio(p
->prio
))
2588 p
->sched_class
= &fair_sched_class
;
2590 if (p
->sched_class
->task_fork
)
2591 p
->sched_class
->task_fork(p
);
2594 cpu
= select_task_rq(p
, SD_BALANCE_FORK
, 0);
2596 set_task_cpu(p
, cpu
);
2598 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
2599 if (likely(sched_info_on()))
2600 memset(&p
->sched_info
, 0, sizeof(p
->sched_info
));
2602 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
2605 #ifdef CONFIG_PREEMPT
2606 /* Want to start with kernel preemption disabled. */
2607 task_thread_info(p
)->preempt_count
= 1;
2609 plist_node_init(&p
->pushable_tasks
, MAX_PRIO
);
2615 * wake_up_new_task - wake up a newly created task for the first time.
2617 * This function will do some initial scheduler statistics housekeeping
2618 * that must be done for every newly created context, then puts the task
2619 * on the runqueue and wakes it.
2621 void wake_up_new_task(struct task_struct
*p
, unsigned long clone_flags
)
2623 unsigned long flags
;
2626 rq
= task_rq_lock(p
, &flags
);
2627 BUG_ON(p
->state
!= TASK_WAKING
);
2628 p
->state
= TASK_RUNNING
;
2629 update_rq_clock(rq
);
2630 activate_task(rq
, p
, 0);
2631 trace_sched_wakeup_new(rq
, p
, 1);
2632 check_preempt_curr(rq
, p
, WF_FORK
);
2634 if (p
->sched_class
->task_wake_up
)
2635 p
->sched_class
->task_wake_up(rq
, p
);
2637 task_rq_unlock(rq
, &flags
);
2640 #ifdef CONFIG_PREEMPT_NOTIFIERS
2643 * preempt_notifier_register - tell me when current is being preempted & rescheduled
2644 * @notifier: notifier struct to register
2646 void preempt_notifier_register(struct preempt_notifier
*notifier
)
2648 hlist_add_head(¬ifier
->link
, ¤t
->preempt_notifiers
);
2650 EXPORT_SYMBOL_GPL(preempt_notifier_register
);
2653 * preempt_notifier_unregister - no longer interested in preemption notifications
2654 * @notifier: notifier struct to unregister
2656 * This is safe to call from within a preemption notifier.
2658 void preempt_notifier_unregister(struct preempt_notifier
*notifier
)
2660 hlist_del(¬ifier
->link
);
2662 EXPORT_SYMBOL_GPL(preempt_notifier_unregister
);
2664 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2666 struct preempt_notifier
*notifier
;
2667 struct hlist_node
*node
;
2669 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
2670 notifier
->ops
->sched_in(notifier
, raw_smp_processor_id());
2674 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2675 struct task_struct
*next
)
2677 struct preempt_notifier
*notifier
;
2678 struct hlist_node
*node
;
2680 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
2681 notifier
->ops
->sched_out(notifier
, next
);
2684 #else /* !CONFIG_PREEMPT_NOTIFIERS */
2686 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2691 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2692 struct task_struct
*next
)
2696 #endif /* CONFIG_PREEMPT_NOTIFIERS */
2699 * prepare_task_switch - prepare to switch tasks
2700 * @rq: the runqueue preparing to switch
2701 * @prev: the current task that is being switched out
2702 * @next: the task we are going to switch to.
2704 * This is called with the rq lock held and interrupts off. It must
2705 * be paired with a subsequent finish_task_switch after the context
2708 * prepare_task_switch sets up locking and calls architecture specific
2712 prepare_task_switch(struct rq
*rq
, struct task_struct
*prev
,
2713 struct task_struct
*next
)
2715 fire_sched_out_preempt_notifiers(prev
, next
);
2716 prepare_lock_switch(rq
, next
);
2717 prepare_arch_switch(next
);
2721 * finish_task_switch - clean up after a task-switch
2722 * @rq: runqueue associated with task-switch
2723 * @prev: the thread we just switched away from.
2725 * finish_task_switch must be called after the context switch, paired
2726 * with a prepare_task_switch call before the context switch.
2727 * finish_task_switch will reconcile locking set up by prepare_task_switch,
2728 * and do any other architecture-specific cleanup actions.
2730 * Note that we may have delayed dropping an mm in context_switch(). If
2731 * so, we finish that here outside of the runqueue lock. (Doing it
2732 * with the lock held can cause deadlocks; see schedule() for
2735 static void finish_task_switch(struct rq
*rq
, struct task_struct
*prev
)
2736 __releases(rq
->lock
)
2738 struct mm_struct
*mm
= rq
->prev_mm
;
2744 * A task struct has one reference for the use as "current".
2745 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
2746 * schedule one last time. The schedule call will never return, and
2747 * the scheduled task must drop that reference.
2748 * The test for TASK_DEAD must occur while the runqueue locks are
2749 * still held, otherwise prev could be scheduled on another cpu, die
2750 * there before we look at prev->state, and then the reference would
2752 * Manfred Spraul <manfred@colorfullife.com>
2754 prev_state
= prev
->state
;
2755 finish_arch_switch(prev
);
2756 perf_event_task_sched_in(current
, cpu_of(rq
));
2757 finish_lock_switch(rq
, prev
);
2759 fire_sched_in_preempt_notifiers(current
);
2762 if (unlikely(prev_state
== TASK_DEAD
)) {
2764 * Remove function-return probe instances associated with this
2765 * task and put them back on the free list.
2767 kprobe_flush_task(prev
);
2768 put_task_struct(prev
);
2774 /* assumes rq->lock is held */
2775 static inline void pre_schedule(struct rq
*rq
, struct task_struct
*prev
)
2777 if (prev
->sched_class
->pre_schedule
)
2778 prev
->sched_class
->pre_schedule(rq
, prev
);
2781 /* rq->lock is NOT held, but preemption is disabled */
2782 static inline void post_schedule(struct rq
*rq
)
2784 if (rq
->post_schedule
) {
2785 unsigned long flags
;
2787 raw_spin_lock_irqsave(&rq
->lock
, flags
);
2788 if (rq
->curr
->sched_class
->post_schedule
)
2789 rq
->curr
->sched_class
->post_schedule(rq
);
2790 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
2792 rq
->post_schedule
= 0;
2798 static inline void pre_schedule(struct rq
*rq
, struct task_struct
*p
)
2802 static inline void post_schedule(struct rq
*rq
)
2809 * schedule_tail - first thing a freshly forked thread must call.
2810 * @prev: the thread we just switched away from.
2812 asmlinkage
void schedule_tail(struct task_struct
*prev
)
2813 __releases(rq
->lock
)
2815 struct rq
*rq
= this_rq();
2817 finish_task_switch(rq
, prev
);
2820 * FIXME: do we need to worry about rq being invalidated by the
2825 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
2826 /* In this case, finish_task_switch does not reenable preemption */
2829 if (current
->set_child_tid
)
2830 put_user(task_pid_vnr(current
), current
->set_child_tid
);
2834 * context_switch - switch to the new MM and the new
2835 * thread's register state.
2838 context_switch(struct rq
*rq
, struct task_struct
*prev
,
2839 struct task_struct
*next
)
2841 struct mm_struct
*mm
, *oldmm
;
2843 prepare_task_switch(rq
, prev
, next
);
2844 trace_sched_switch(rq
, prev
, next
);
2846 oldmm
= prev
->active_mm
;
2848 * For paravirt, this is coupled with an exit in switch_to to
2849 * combine the page table reload and the switch backend into
2852 arch_start_context_switch(prev
);
2855 next
->active_mm
= oldmm
;
2856 atomic_inc(&oldmm
->mm_count
);
2857 enter_lazy_tlb(oldmm
, next
);
2859 switch_mm(oldmm
, mm
, next
);
2861 if (likely(!prev
->mm
)) {
2862 prev
->active_mm
= NULL
;
2863 rq
->prev_mm
= oldmm
;
2866 * Since the runqueue lock will be released by the next
2867 * task (which is an invalid locking op but in the case
2868 * of the scheduler it's an obvious special-case), so we
2869 * do an early lockdep release here:
2871 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
2872 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
2875 /* Here we just switch the register state and the stack. */
2876 switch_to(prev
, next
, prev
);
2880 * this_rq must be evaluated again because prev may have moved
2881 * CPUs since it called schedule(), thus the 'rq' on its stack
2882 * frame will be invalid.
2884 finish_task_switch(this_rq(), prev
);
2888 * nr_running, nr_uninterruptible and nr_context_switches:
2890 * externally visible scheduler statistics: current number of runnable
2891 * threads, current number of uninterruptible-sleeping threads, total
2892 * number of context switches performed since bootup.
2894 unsigned long nr_running(void)
2896 unsigned long i
, sum
= 0;
2898 for_each_online_cpu(i
)
2899 sum
+= cpu_rq(i
)->nr_running
;
2904 unsigned long nr_uninterruptible(void)
2906 unsigned long i
, sum
= 0;
2908 for_each_possible_cpu(i
)
2909 sum
+= cpu_rq(i
)->nr_uninterruptible
;
2912 * Since we read the counters lockless, it might be slightly
2913 * inaccurate. Do not allow it to go below zero though:
2915 if (unlikely((long)sum
< 0))
2921 unsigned long long nr_context_switches(void)
2924 unsigned long long sum
= 0;
2926 for_each_possible_cpu(i
)
2927 sum
+= cpu_rq(i
)->nr_switches
;
2932 unsigned long nr_iowait(void)
2934 unsigned long i
, sum
= 0;
2936 for_each_possible_cpu(i
)
2937 sum
+= atomic_read(&cpu_rq(i
)->nr_iowait
);
2942 unsigned long nr_iowait_cpu(void)
2944 struct rq
*this = this_rq();
2945 return atomic_read(&this->nr_iowait
);
2948 unsigned long this_cpu_load(void)
2950 struct rq
*this = this_rq();
2951 return this->cpu_load
[0];
2955 /* Variables and functions for calc_load */
2956 static atomic_long_t calc_load_tasks
;
2957 static unsigned long calc_load_update
;
2958 unsigned long avenrun
[3];
2959 EXPORT_SYMBOL(avenrun
);
2962 * get_avenrun - get the load average array
2963 * @loads: pointer to dest load array
2964 * @offset: offset to add
2965 * @shift: shift count to shift the result left
2967 * These values are estimates at best, so no need for locking.
2969 void get_avenrun(unsigned long *loads
, unsigned long offset
, int shift
)
2971 loads
[0] = (avenrun
[0] + offset
) << shift
;
2972 loads
[1] = (avenrun
[1] + offset
) << shift
;
2973 loads
[2] = (avenrun
[2] + offset
) << shift
;
2976 static unsigned long
2977 calc_load(unsigned long load
, unsigned long exp
, unsigned long active
)
2980 load
+= active
* (FIXED_1
- exp
);
2981 return load
>> FSHIFT
;
2985 * calc_load - update the avenrun load estimates 10 ticks after the
2986 * CPUs have updated calc_load_tasks.
2988 void calc_global_load(void)
2990 unsigned long upd
= calc_load_update
+ 10;
2993 if (time_before(jiffies
, upd
))
2996 active
= atomic_long_read(&calc_load_tasks
);
2997 active
= active
> 0 ? active
* FIXED_1
: 0;
2999 avenrun
[0] = calc_load(avenrun
[0], EXP_1
, active
);
3000 avenrun
[1] = calc_load(avenrun
[1], EXP_5
, active
);
3001 avenrun
[2] = calc_load(avenrun
[2], EXP_15
, active
);
3003 calc_load_update
+= LOAD_FREQ
;
3007 * Either called from update_cpu_load() or from a cpu going idle
3009 static void calc_load_account_active(struct rq
*this_rq
)
3011 long nr_active
, delta
;
3013 nr_active
= this_rq
->nr_running
;
3014 nr_active
+= (long) this_rq
->nr_uninterruptible
;
3016 if (nr_active
!= this_rq
->calc_load_active
) {
3017 delta
= nr_active
- this_rq
->calc_load_active
;
3018 this_rq
->calc_load_active
= nr_active
;
3019 atomic_long_add(delta
, &calc_load_tasks
);
3024 * Update rq->cpu_load[] statistics. This function is usually called every
3025 * scheduler tick (TICK_NSEC).
3027 static void update_cpu_load(struct rq
*this_rq
)
3029 unsigned long this_load
= this_rq
->load
.weight
;
3032 this_rq
->nr_load_updates
++;
3034 /* Update our load: */
3035 for (i
= 0, scale
= 1; i
< CPU_LOAD_IDX_MAX
; i
++, scale
+= scale
) {
3036 unsigned long old_load
, new_load
;
3038 /* scale is effectively 1 << i now, and >> i divides by scale */
3040 old_load
= this_rq
->cpu_load
[i
];
3041 new_load
= this_load
;
3043 * Round up the averaging division if load is increasing. This
3044 * prevents us from getting stuck on 9 if the load is 10, for
3047 if (new_load
> old_load
)
3048 new_load
+= scale
-1;
3049 this_rq
->cpu_load
[i
] = (old_load
*(scale
-1) + new_load
) >> i
;
3052 if (time_after_eq(jiffies
, this_rq
->calc_load_update
)) {
3053 this_rq
->calc_load_update
+= LOAD_FREQ
;
3054 calc_load_account_active(this_rq
);
3061 * double_rq_lock - safely lock two runqueues
3063 * Note this does not disable interrupts like task_rq_lock,
3064 * you need to do so manually before calling.
3066 static void double_rq_lock(struct rq
*rq1
, struct rq
*rq2
)
3067 __acquires(rq1
->lock
)
3068 __acquires(rq2
->lock
)
3070 BUG_ON(!irqs_disabled());
3072 raw_spin_lock(&rq1
->lock
);
3073 __acquire(rq2
->lock
); /* Fake it out ;) */
3076 raw_spin_lock(&rq1
->lock
);
3077 raw_spin_lock_nested(&rq2
->lock
, SINGLE_DEPTH_NESTING
);
3079 raw_spin_lock(&rq2
->lock
);
3080 raw_spin_lock_nested(&rq1
->lock
, SINGLE_DEPTH_NESTING
);
3083 update_rq_clock(rq1
);
3084 update_rq_clock(rq2
);
3088 * double_rq_unlock - safely unlock two runqueues
3090 * Note this does not restore interrupts like task_rq_unlock,
3091 * you need to do so manually after calling.
3093 static void double_rq_unlock(struct rq
*rq1
, struct rq
*rq2
)
3094 __releases(rq1
->lock
)
3095 __releases(rq2
->lock
)
3097 raw_spin_unlock(&rq1
->lock
);
3099 raw_spin_unlock(&rq2
->lock
);
3101 __release(rq2
->lock
);
3105 * If dest_cpu is allowed for this process, migrate the task to it.
3106 * This is accomplished by forcing the cpu_allowed mask to only
3107 * allow dest_cpu, which will force the cpu onto dest_cpu. Then
3108 * the cpu_allowed mask is restored.
3110 static void sched_migrate_task(struct task_struct
*p
, int dest_cpu
)
3112 struct migration_req req
;
3113 unsigned long flags
;
3116 rq
= task_rq_lock(p
, &flags
);
3117 if (!cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
)
3118 || unlikely(!cpu_active(dest_cpu
)))
3121 /* force the process onto the specified CPU */
3122 if (migrate_task(p
, dest_cpu
, &req
)) {
3123 /* Need to wait for migration thread (might exit: take ref). */
3124 struct task_struct
*mt
= rq
->migration_thread
;
3126 get_task_struct(mt
);
3127 task_rq_unlock(rq
, &flags
);
3128 wake_up_process(mt
);
3129 put_task_struct(mt
);
3130 wait_for_completion(&req
.done
);
3135 task_rq_unlock(rq
, &flags
);
3139 * sched_exec - execve() is a valuable balancing opportunity, because at
3140 * this point the task has the smallest effective memory and cache footprint.
3142 void sched_exec(void)
3144 int new_cpu
, this_cpu
= get_cpu();
3145 new_cpu
= select_task_rq(current
, SD_BALANCE_EXEC
, 0);
3147 if (new_cpu
!= this_cpu
)
3148 sched_migrate_task(current
, new_cpu
);
3152 * pull_task - move a task from a remote runqueue to the local runqueue.
3153 * Both runqueues must be locked.
3155 static void pull_task(struct rq
*src_rq
, struct task_struct
*p
,
3156 struct rq
*this_rq
, int this_cpu
)
3158 deactivate_task(src_rq
, p
, 0);
3159 set_task_cpu(p
, this_cpu
);
3160 activate_task(this_rq
, p
, 0);
3161 check_preempt_curr(this_rq
, p
, 0);
3165 * can_migrate_task - may task p from runqueue rq be migrated to this_cpu?
3168 int can_migrate_task(struct task_struct
*p
, struct rq
*rq
, int this_cpu
,
3169 struct sched_domain
*sd
, enum cpu_idle_type idle
,
3172 int tsk_cache_hot
= 0;
3174 * We do not migrate tasks that are:
3175 * 1) running (obviously), or
3176 * 2) cannot be migrated to this CPU due to cpus_allowed, or
3177 * 3) are cache-hot on their current CPU.
3179 if (!cpumask_test_cpu(this_cpu
, &p
->cpus_allowed
)) {
3180 schedstat_inc(p
, se
.nr_failed_migrations_affine
);
3185 if (task_running(rq
, p
)) {
3186 schedstat_inc(p
, se
.nr_failed_migrations_running
);
3191 * Aggressive migration if:
3192 * 1) task is cache cold, or
3193 * 2) too many balance attempts have failed.
3196 tsk_cache_hot
= task_hot(p
, rq
->clock
, sd
);
3197 if (!tsk_cache_hot
||
3198 sd
->nr_balance_failed
> sd
->cache_nice_tries
) {
3199 #ifdef CONFIG_SCHEDSTATS
3200 if (tsk_cache_hot
) {
3201 schedstat_inc(sd
, lb_hot_gained
[idle
]);
3202 schedstat_inc(p
, se
.nr_forced_migrations
);
3208 if (tsk_cache_hot
) {
3209 schedstat_inc(p
, se
.nr_failed_migrations_hot
);
3215 static unsigned long
3216 balance_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
3217 unsigned long max_load_move
, struct sched_domain
*sd
,
3218 enum cpu_idle_type idle
, int *all_pinned
,
3219 int *this_best_prio
, struct rq_iterator
*iterator
)
3221 int loops
= 0, pulled
= 0, pinned
= 0;
3222 struct task_struct
*p
;
3223 long rem_load_move
= max_load_move
;
3225 if (max_load_move
== 0)
3231 * Start the load-balancing iterator:
3233 p
= iterator
->start(iterator
->arg
);
3235 if (!p
|| loops
++ > sysctl_sched_nr_migrate
)
3238 if ((p
->se
.load
.weight
>> 1) > rem_load_move
||
3239 !can_migrate_task(p
, busiest
, this_cpu
, sd
, idle
, &pinned
)) {
3240 p
= iterator
->next(iterator
->arg
);
3244 pull_task(busiest
, p
, this_rq
, this_cpu
);
3246 rem_load_move
-= p
->se
.load
.weight
;
3248 #ifdef CONFIG_PREEMPT
3250 * NEWIDLE balancing is a source of latency, so preemptible kernels
3251 * will stop after the first task is pulled to minimize the critical
3254 if (idle
== CPU_NEWLY_IDLE
)
3259 * We only want to steal up to the prescribed amount of weighted load.
3261 if (rem_load_move
> 0) {
3262 if (p
->prio
< *this_best_prio
)
3263 *this_best_prio
= p
->prio
;
3264 p
= iterator
->next(iterator
->arg
);
3269 * Right now, this is one of only two places pull_task() is called,
3270 * so we can safely collect pull_task() stats here rather than
3271 * inside pull_task().
3273 schedstat_add(sd
, lb_gained
[idle
], pulled
);
3276 *all_pinned
= pinned
;
3278 return max_load_move
- rem_load_move
;
3282 * move_tasks tries to move up to max_load_move weighted load from busiest to
3283 * this_rq, as part of a balancing operation within domain "sd".
3284 * Returns 1 if successful and 0 otherwise.
3286 * Called with both runqueues locked.
3288 static int move_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
3289 unsigned long max_load_move
,
3290 struct sched_domain
*sd
, enum cpu_idle_type idle
,
3293 const struct sched_class
*class = sched_class_highest
;
3294 unsigned long total_load_moved
= 0;
3295 int this_best_prio
= this_rq
->curr
->prio
;
3299 class->load_balance(this_rq
, this_cpu
, busiest
,
3300 max_load_move
- total_load_moved
,
3301 sd
, idle
, all_pinned
, &this_best_prio
);
3302 class = class->next
;
3304 #ifdef CONFIG_PREEMPT
3306 * NEWIDLE balancing is a source of latency, so preemptible
3307 * kernels will stop after the first task is pulled to minimize
3308 * the critical section.
3310 if (idle
== CPU_NEWLY_IDLE
&& this_rq
->nr_running
)
3313 } while (class && max_load_move
> total_load_moved
);
3315 return total_load_moved
> 0;
3319 iter_move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
3320 struct sched_domain
*sd
, enum cpu_idle_type idle
,
3321 struct rq_iterator
*iterator
)
3323 struct task_struct
*p
= iterator
->start(iterator
->arg
);
3327 if (can_migrate_task(p
, busiest
, this_cpu
, sd
, idle
, &pinned
)) {
3328 pull_task(busiest
, p
, this_rq
, this_cpu
);
3330 * Right now, this is only the second place pull_task()
3331 * is called, so we can safely collect pull_task()
3332 * stats here rather than inside pull_task().
3334 schedstat_inc(sd
, lb_gained
[idle
]);
3338 p
= iterator
->next(iterator
->arg
);
3345 * move_one_task tries to move exactly one task from busiest to this_rq, as
3346 * part of active balancing operations within "domain".
3347 * Returns 1 if successful and 0 otherwise.
3349 * Called with both runqueues locked.
3351 static int move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
3352 struct sched_domain
*sd
, enum cpu_idle_type idle
)
3354 const struct sched_class
*class;
3356 for_each_class(class) {
3357 if (class->move_one_task(this_rq
, this_cpu
, busiest
, sd
, idle
))
3363 /********** Helpers for find_busiest_group ************************/
3365 * sd_lb_stats - Structure to store the statistics of a sched_domain
3366 * during load balancing.
3368 struct sd_lb_stats
{
3369 struct sched_group
*busiest
; /* Busiest group in this sd */
3370 struct sched_group
*this; /* Local group in this sd */
3371 unsigned long total_load
; /* Total load of all groups in sd */
3372 unsigned long total_pwr
; /* Total power of all groups in sd */
3373 unsigned long avg_load
; /* Average load across all groups in sd */
3375 /** Statistics of this group */
3376 unsigned long this_load
;
3377 unsigned long this_load_per_task
;
3378 unsigned long this_nr_running
;
3380 /* Statistics of the busiest group */
3381 unsigned long max_load
;
3382 unsigned long busiest_load_per_task
;
3383 unsigned long busiest_nr_running
;
3385 int group_imb
; /* Is there imbalance in this sd */
3386 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3387 int power_savings_balance
; /* Is powersave balance needed for this sd */
3388 struct sched_group
*group_min
; /* Least loaded group in sd */
3389 struct sched_group
*group_leader
; /* Group which relieves group_min */
3390 unsigned long min_load_per_task
; /* load_per_task in group_min */
3391 unsigned long leader_nr_running
; /* Nr running of group_leader */
3392 unsigned long min_nr_running
; /* Nr running of group_min */
3397 * sg_lb_stats - stats of a sched_group required for load_balancing
3399 struct sg_lb_stats
{
3400 unsigned long avg_load
; /*Avg load across the CPUs of the group */
3401 unsigned long group_load
; /* Total load over the CPUs of the group */
3402 unsigned long sum_nr_running
; /* Nr tasks running in the group */
3403 unsigned long sum_weighted_load
; /* Weighted load of group's tasks */
3404 unsigned long group_capacity
;
3405 int group_imb
; /* Is there an imbalance in the group ? */
3409 * group_first_cpu - Returns the first cpu in the cpumask of a sched_group.
3410 * @group: The group whose first cpu is to be returned.
3412 static inline unsigned int group_first_cpu(struct sched_group
*group
)
3414 return cpumask_first(sched_group_cpus(group
));
3418 * get_sd_load_idx - Obtain the load index for a given sched domain.
3419 * @sd: The sched_domain whose load_idx is to be obtained.
3420 * @idle: The Idle status of the CPU for whose sd load_icx is obtained.
3422 static inline int get_sd_load_idx(struct sched_domain
*sd
,
3423 enum cpu_idle_type idle
)
3429 load_idx
= sd
->busy_idx
;
3432 case CPU_NEWLY_IDLE
:
3433 load_idx
= sd
->newidle_idx
;
3436 load_idx
= sd
->idle_idx
;
3444 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3446 * init_sd_power_savings_stats - Initialize power savings statistics for
3447 * the given sched_domain, during load balancing.
3449 * @sd: Sched domain whose power-savings statistics are to be initialized.
3450 * @sds: Variable containing the statistics for sd.
3451 * @idle: Idle status of the CPU at which we're performing load-balancing.
3453 static inline void init_sd_power_savings_stats(struct sched_domain
*sd
,
3454 struct sd_lb_stats
*sds
, enum cpu_idle_type idle
)
3457 * Busy processors will not participate in power savings
3460 if (idle
== CPU_NOT_IDLE
|| !(sd
->flags
& SD_POWERSAVINGS_BALANCE
))
3461 sds
->power_savings_balance
= 0;
3463 sds
->power_savings_balance
= 1;
3464 sds
->min_nr_running
= ULONG_MAX
;
3465 sds
->leader_nr_running
= 0;
3470 * update_sd_power_savings_stats - Update the power saving stats for a
3471 * sched_domain while performing load balancing.
3473 * @group: sched_group belonging to the sched_domain under consideration.
3474 * @sds: Variable containing the statistics of the sched_domain
3475 * @local_group: Does group contain the CPU for which we're performing
3477 * @sgs: Variable containing the statistics of the group.
3479 static inline void update_sd_power_savings_stats(struct sched_group
*group
,
3480 struct sd_lb_stats
*sds
, int local_group
, struct sg_lb_stats
*sgs
)
3483 if (!sds
->power_savings_balance
)
3487 * If the local group is idle or completely loaded
3488 * no need to do power savings balance at this domain
3490 if (local_group
&& (sds
->this_nr_running
>= sgs
->group_capacity
||
3491 !sds
->this_nr_running
))
3492 sds
->power_savings_balance
= 0;
3495 * If a group is already running at full capacity or idle,
3496 * don't include that group in power savings calculations
3498 if (!sds
->power_savings_balance
||
3499 sgs
->sum_nr_running
>= sgs
->group_capacity
||
3500 !sgs
->sum_nr_running
)
3504 * Calculate the group which has the least non-idle load.
3505 * This is the group from where we need to pick up the load
3508 if ((sgs
->sum_nr_running
< sds
->min_nr_running
) ||
3509 (sgs
->sum_nr_running
== sds
->min_nr_running
&&
3510 group_first_cpu(group
) > group_first_cpu(sds
->group_min
))) {
3511 sds
->group_min
= group
;
3512 sds
->min_nr_running
= sgs
->sum_nr_running
;
3513 sds
->min_load_per_task
= sgs
->sum_weighted_load
/
3514 sgs
->sum_nr_running
;
3518 * Calculate the group which is almost near its
3519 * capacity but still has some space to pick up some load
3520 * from other group and save more power
3522 if (sgs
->sum_nr_running
+ 1 > sgs
->group_capacity
)
3525 if (sgs
->sum_nr_running
> sds
->leader_nr_running
||
3526 (sgs
->sum_nr_running
== sds
->leader_nr_running
&&
3527 group_first_cpu(group
) < group_first_cpu(sds
->group_leader
))) {
3528 sds
->group_leader
= group
;
3529 sds
->leader_nr_running
= sgs
->sum_nr_running
;
3534 * check_power_save_busiest_group - see if there is potential for some power-savings balance
3535 * @sds: Variable containing the statistics of the sched_domain
3536 * under consideration.
3537 * @this_cpu: Cpu at which we're currently performing load-balancing.
3538 * @imbalance: Variable to store the imbalance.
3541 * Check if we have potential to perform some power-savings balance.
3542 * If yes, set the busiest group to be the least loaded group in the
3543 * sched_domain, so that it's CPUs can be put to idle.
3545 * Returns 1 if there is potential to perform power-savings balance.
3548 static inline int check_power_save_busiest_group(struct sd_lb_stats
*sds
,
3549 int this_cpu
, unsigned long *imbalance
)
3551 if (!sds
->power_savings_balance
)
3554 if (sds
->this != sds
->group_leader
||
3555 sds
->group_leader
== sds
->group_min
)
3558 *imbalance
= sds
->min_load_per_task
;
3559 sds
->busiest
= sds
->group_min
;
3564 #else /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
3565 static inline void init_sd_power_savings_stats(struct sched_domain
*sd
,
3566 struct sd_lb_stats
*sds
, enum cpu_idle_type idle
)
3571 static inline void update_sd_power_savings_stats(struct sched_group
*group
,
3572 struct sd_lb_stats
*sds
, int local_group
, struct sg_lb_stats
*sgs
)
3577 static inline int check_power_save_busiest_group(struct sd_lb_stats
*sds
,
3578 int this_cpu
, unsigned long *imbalance
)
3582 #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
3585 unsigned long default_scale_freq_power(struct sched_domain
*sd
, int cpu
)
3587 return SCHED_LOAD_SCALE
;
3590 unsigned long __weak
arch_scale_freq_power(struct sched_domain
*sd
, int cpu
)
3592 return default_scale_freq_power(sd
, cpu
);
3595 unsigned long default_scale_smt_power(struct sched_domain
*sd
, int cpu
)
3597 unsigned long weight
= cpumask_weight(sched_domain_span(sd
));
3598 unsigned long smt_gain
= sd
->smt_gain
;
3605 unsigned long __weak
arch_scale_smt_power(struct sched_domain
*sd
, int cpu
)
3607 return default_scale_smt_power(sd
, cpu
);
3610 unsigned long scale_rt_power(int cpu
)
3612 struct rq
*rq
= cpu_rq(cpu
);
3613 u64 total
, available
;
3615 sched_avg_update(rq
);
3617 total
= sched_avg_period() + (rq
->clock
- rq
->age_stamp
);
3618 available
= total
- rq
->rt_avg
;
3620 if (unlikely((s64
)total
< SCHED_LOAD_SCALE
))
3621 total
= SCHED_LOAD_SCALE
;
3623 total
>>= SCHED_LOAD_SHIFT
;
3625 return div_u64(available
, total
);
3628 static void update_cpu_power(struct sched_domain
*sd
, int cpu
)
3630 unsigned long weight
= cpumask_weight(sched_domain_span(sd
));
3631 unsigned long power
= SCHED_LOAD_SCALE
;
3632 struct sched_group
*sdg
= sd
->groups
;
3634 if (sched_feat(ARCH_POWER
))
3635 power
*= arch_scale_freq_power(sd
, cpu
);
3637 power
*= default_scale_freq_power(sd
, cpu
);
3639 power
>>= SCHED_LOAD_SHIFT
;
3641 if ((sd
->flags
& SD_SHARE_CPUPOWER
) && weight
> 1) {
3642 if (sched_feat(ARCH_POWER
))
3643 power
*= arch_scale_smt_power(sd
, cpu
);
3645 power
*= default_scale_smt_power(sd
, cpu
);
3647 power
>>= SCHED_LOAD_SHIFT
;
3650 power
*= scale_rt_power(cpu
);
3651 power
>>= SCHED_LOAD_SHIFT
;
3656 sdg
->cpu_power
= power
;
3659 static void update_group_power(struct sched_domain
*sd
, int cpu
)
3661 struct sched_domain
*child
= sd
->child
;
3662 struct sched_group
*group
, *sdg
= sd
->groups
;
3663 unsigned long power
;
3666 update_cpu_power(sd
, cpu
);
3672 group
= child
->groups
;
3674 power
+= group
->cpu_power
;
3675 group
= group
->next
;
3676 } while (group
!= child
->groups
);
3678 sdg
->cpu_power
= power
;
3682 * update_sg_lb_stats - Update sched_group's statistics for load balancing.
3683 * @sd: The sched_domain whose statistics are to be updated.
3684 * @group: sched_group whose statistics are to be updated.
3685 * @this_cpu: Cpu for which load balance is currently performed.
3686 * @idle: Idle status of this_cpu
3687 * @load_idx: Load index of sched_domain of this_cpu for load calc.
3688 * @sd_idle: Idle status of the sched_domain containing group.
3689 * @local_group: Does group contain this_cpu.
3690 * @cpus: Set of cpus considered for load balancing.
3691 * @balance: Should we balance.
3692 * @sgs: variable to hold the statistics for this group.
3694 static inline void update_sg_lb_stats(struct sched_domain
*sd
,
3695 struct sched_group
*group
, int this_cpu
,
3696 enum cpu_idle_type idle
, int load_idx
, int *sd_idle
,
3697 int local_group
, const struct cpumask
*cpus
,
3698 int *balance
, struct sg_lb_stats
*sgs
)
3700 unsigned long load
, max_cpu_load
, min_cpu_load
;
3702 unsigned int balance_cpu
= -1, first_idle_cpu
= 0;
3703 unsigned long sum_avg_load_per_task
;
3704 unsigned long avg_load_per_task
;
3707 balance_cpu
= group_first_cpu(group
);
3708 if (balance_cpu
== this_cpu
)
3709 update_group_power(sd
, this_cpu
);
3712 /* Tally up the load of all CPUs in the group */
3713 sum_avg_load_per_task
= avg_load_per_task
= 0;
3715 min_cpu_load
= ~0UL;
3717 for_each_cpu_and(i
, sched_group_cpus(group
), cpus
) {
3718 struct rq
*rq
= cpu_rq(i
);
3720 if (*sd_idle
&& rq
->nr_running
)
3723 /* Bias balancing toward cpus of our domain */
3725 if (idle_cpu(i
) && !first_idle_cpu
) {
3730 load
= target_load(i
, load_idx
);
3732 load
= source_load(i
, load_idx
);
3733 if (load
> max_cpu_load
)
3734 max_cpu_load
= load
;
3735 if (min_cpu_load
> load
)
3736 min_cpu_load
= load
;
3739 sgs
->group_load
+= load
;
3740 sgs
->sum_nr_running
+= rq
->nr_running
;
3741 sgs
->sum_weighted_load
+= weighted_cpuload(i
);
3743 sum_avg_load_per_task
+= cpu_avg_load_per_task(i
);
3747 * First idle cpu or the first cpu(busiest) in this sched group
3748 * is eligible for doing load balancing at this and above
3749 * domains. In the newly idle case, we will allow all the cpu's
3750 * to do the newly idle load balance.
3752 if (idle
!= CPU_NEWLY_IDLE
&& local_group
&&
3753 balance_cpu
!= this_cpu
&& balance
) {
3758 /* Adjust by relative CPU power of the group */
3759 sgs
->avg_load
= (sgs
->group_load
* SCHED_LOAD_SCALE
) / group
->cpu_power
;
3763 * Consider the group unbalanced when the imbalance is larger
3764 * than the average weight of two tasks.
3766 * APZ: with cgroup the avg task weight can vary wildly and
3767 * might not be a suitable number - should we keep a
3768 * normalized nr_running number somewhere that negates
3771 avg_load_per_task
= (sum_avg_load_per_task
* SCHED_LOAD_SCALE
) /
3774 if ((max_cpu_load
- min_cpu_load
) > 2*avg_load_per_task
)
3777 sgs
->group_capacity
=
3778 DIV_ROUND_CLOSEST(group
->cpu_power
, SCHED_LOAD_SCALE
);
3782 * update_sd_lb_stats - Update sched_group's statistics for load balancing.
3783 * @sd: sched_domain whose statistics are to be updated.
3784 * @this_cpu: Cpu for which load balance is currently performed.
3785 * @idle: Idle status of this_cpu
3786 * @sd_idle: Idle status of the sched_domain containing group.
3787 * @cpus: Set of cpus considered for load balancing.
3788 * @balance: Should we balance.
3789 * @sds: variable to hold the statistics for this sched_domain.
3791 static inline void update_sd_lb_stats(struct sched_domain
*sd
, int this_cpu
,
3792 enum cpu_idle_type idle
, int *sd_idle
,
3793 const struct cpumask
*cpus
, int *balance
,
3794 struct sd_lb_stats
*sds
)
3796 struct sched_domain
*child
= sd
->child
;
3797 struct sched_group
*group
= sd
->groups
;
3798 struct sg_lb_stats sgs
;
3799 int load_idx
, prefer_sibling
= 0;
3801 if (child
&& child
->flags
& SD_PREFER_SIBLING
)
3804 init_sd_power_savings_stats(sd
, sds
, idle
);
3805 load_idx
= get_sd_load_idx(sd
, idle
);
3810 local_group
= cpumask_test_cpu(this_cpu
,
3811 sched_group_cpus(group
));
3812 memset(&sgs
, 0, sizeof(sgs
));
3813 update_sg_lb_stats(sd
, group
, this_cpu
, idle
, load_idx
, sd_idle
,
3814 local_group
, cpus
, balance
, &sgs
);
3816 if (local_group
&& balance
&& !(*balance
))
3819 sds
->total_load
+= sgs
.group_load
;
3820 sds
->total_pwr
+= group
->cpu_power
;
3823 * In case the child domain prefers tasks go to siblings
3824 * first, lower the group capacity to one so that we'll try
3825 * and move all the excess tasks away.
3828 sgs
.group_capacity
= min(sgs
.group_capacity
, 1UL);
3831 sds
->this_load
= sgs
.avg_load
;
3833 sds
->this_nr_running
= sgs
.sum_nr_running
;
3834 sds
->this_load_per_task
= sgs
.sum_weighted_load
;
3835 } else if (sgs
.avg_load
> sds
->max_load
&&
3836 (sgs
.sum_nr_running
> sgs
.group_capacity
||
3838 sds
->max_load
= sgs
.avg_load
;
3839 sds
->busiest
= group
;
3840 sds
->busiest_nr_running
= sgs
.sum_nr_running
;
3841 sds
->busiest_load_per_task
= sgs
.sum_weighted_load
;
3842 sds
->group_imb
= sgs
.group_imb
;
3845 update_sd_power_savings_stats(group
, sds
, local_group
, &sgs
);
3846 group
= group
->next
;
3847 } while (group
!= sd
->groups
);
3851 * fix_small_imbalance - Calculate the minor imbalance that exists
3852 * amongst the groups of a sched_domain, during
3854 * @sds: Statistics of the sched_domain whose imbalance is to be calculated.
3855 * @this_cpu: The cpu at whose sched_domain we're performing load-balance.
3856 * @imbalance: Variable to store the imbalance.
3858 static inline void fix_small_imbalance(struct sd_lb_stats
*sds
,
3859 int this_cpu
, unsigned long *imbalance
)
3861 unsigned long tmp
, pwr_now
= 0, pwr_move
= 0;
3862 unsigned int imbn
= 2;
3864 if (sds
->this_nr_running
) {
3865 sds
->this_load_per_task
/= sds
->this_nr_running
;
3866 if (sds
->busiest_load_per_task
>
3867 sds
->this_load_per_task
)
3870 sds
->this_load_per_task
=
3871 cpu_avg_load_per_task(this_cpu
);
3873 if (sds
->max_load
- sds
->this_load
+ sds
->busiest_load_per_task
>=
3874 sds
->busiest_load_per_task
* imbn
) {
3875 *imbalance
= sds
->busiest_load_per_task
;
3880 * OK, we don't have enough imbalance to justify moving tasks,
3881 * however we may be able to increase total CPU power used by
3885 pwr_now
+= sds
->busiest
->cpu_power
*
3886 min(sds
->busiest_load_per_task
, sds
->max_load
);
3887 pwr_now
+= sds
->this->cpu_power
*
3888 min(sds
->this_load_per_task
, sds
->this_load
);
3889 pwr_now
/= SCHED_LOAD_SCALE
;
3891 /* Amount of load we'd subtract */
3892 tmp
= (sds
->busiest_load_per_task
* SCHED_LOAD_SCALE
) /
3893 sds
->busiest
->cpu_power
;
3894 if (sds
->max_load
> tmp
)
3895 pwr_move
+= sds
->busiest
->cpu_power
*
3896 min(sds
->busiest_load_per_task
, sds
->max_load
- tmp
);
3898 /* Amount of load we'd add */
3899 if (sds
->max_load
* sds
->busiest
->cpu_power
<
3900 sds
->busiest_load_per_task
* SCHED_LOAD_SCALE
)
3901 tmp
= (sds
->max_load
* sds
->busiest
->cpu_power
) /
3902 sds
->this->cpu_power
;
3904 tmp
= (sds
->busiest_load_per_task
* SCHED_LOAD_SCALE
) /
3905 sds
->this->cpu_power
;
3906 pwr_move
+= sds
->this->cpu_power
*
3907 min(sds
->this_load_per_task
, sds
->this_load
+ tmp
);
3908 pwr_move
/= SCHED_LOAD_SCALE
;
3910 /* Move if we gain throughput */
3911 if (pwr_move
> pwr_now
)
3912 *imbalance
= sds
->busiest_load_per_task
;
3916 * calculate_imbalance - Calculate the amount of imbalance present within the
3917 * groups of a given sched_domain during load balance.
3918 * @sds: statistics of the sched_domain whose imbalance is to be calculated.
3919 * @this_cpu: Cpu for which currently load balance is being performed.
3920 * @imbalance: The variable to store the imbalance.
3922 static inline void calculate_imbalance(struct sd_lb_stats
*sds
, int this_cpu
,
3923 unsigned long *imbalance
)
3925 unsigned long max_pull
;
3927 * In the presence of smp nice balancing, certain scenarios can have
3928 * max load less than avg load(as we skip the groups at or below
3929 * its cpu_power, while calculating max_load..)
3931 if (sds
->max_load
< sds
->avg_load
) {
3933 return fix_small_imbalance(sds
, this_cpu
, imbalance
);
3936 /* Don't want to pull so many tasks that a group would go idle */
3937 max_pull
= min(sds
->max_load
- sds
->avg_load
,
3938 sds
->max_load
- sds
->busiest_load_per_task
);
3940 /* How much load to actually move to equalise the imbalance */
3941 *imbalance
= min(max_pull
* sds
->busiest
->cpu_power
,
3942 (sds
->avg_load
- sds
->this_load
) * sds
->this->cpu_power
)
3946 * if *imbalance is less than the average load per runnable task
3947 * there is no gaurantee that any tasks will be moved so we'll have
3948 * a think about bumping its value to force at least one task to be
3951 if (*imbalance
< sds
->busiest_load_per_task
)
3952 return fix_small_imbalance(sds
, this_cpu
, imbalance
);
3955 /******* find_busiest_group() helpers end here *********************/
3958 * find_busiest_group - Returns the busiest group within the sched_domain
3959 * if there is an imbalance. If there isn't an imbalance, and
3960 * the user has opted for power-savings, it returns a group whose
3961 * CPUs can be put to idle by rebalancing those tasks elsewhere, if
3962 * such a group exists.
3964 * Also calculates the amount of weighted load which should be moved
3965 * to restore balance.
3967 * @sd: The sched_domain whose busiest group is to be returned.
3968 * @this_cpu: The cpu for which load balancing is currently being performed.
3969 * @imbalance: Variable which stores amount of weighted load which should
3970 * be moved to restore balance/put a group to idle.
3971 * @idle: The idle status of this_cpu.
3972 * @sd_idle: The idleness of sd
3973 * @cpus: The set of CPUs under consideration for load-balancing.
3974 * @balance: Pointer to a variable indicating if this_cpu
3975 * is the appropriate cpu to perform load balancing at this_level.
3977 * Returns: - the busiest group if imbalance exists.
3978 * - If no imbalance and user has opted for power-savings balance,
3979 * return the least loaded group whose CPUs can be
3980 * put to idle by rebalancing its tasks onto our group.
3982 static struct sched_group
*
3983 find_busiest_group(struct sched_domain
*sd
, int this_cpu
,
3984 unsigned long *imbalance
, enum cpu_idle_type idle
,
3985 int *sd_idle
, const struct cpumask
*cpus
, int *balance
)
3987 struct sd_lb_stats sds
;
3989 memset(&sds
, 0, sizeof(sds
));
3992 * Compute the various statistics relavent for load balancing at
3995 update_sd_lb_stats(sd
, this_cpu
, idle
, sd_idle
, cpus
,
3998 /* Cases where imbalance does not exist from POV of this_cpu */
3999 /* 1) this_cpu is not the appropriate cpu to perform load balancing
4001 * 2) There is no busy sibling group to pull from.
4002 * 3) This group is the busiest group.
4003 * 4) This group is more busy than the avg busieness at this
4005 * 5) The imbalance is within the specified limit.
4006 * 6) Any rebalance would lead to ping-pong
4008 if (balance
&& !(*balance
))
4011 if (!sds
.busiest
|| sds
.busiest_nr_running
== 0)
4014 if (sds
.this_load
>= sds
.max_load
)
4017 sds
.avg_load
= (SCHED_LOAD_SCALE
* sds
.total_load
) / sds
.total_pwr
;
4019 if (sds
.this_load
>= sds
.avg_load
)
4022 if (100 * sds
.max_load
<= sd
->imbalance_pct
* sds
.this_load
)
4025 sds
.busiest_load_per_task
/= sds
.busiest_nr_running
;
4027 sds
.busiest_load_per_task
=
4028 min(sds
.busiest_load_per_task
, sds
.avg_load
);
4031 * We're trying to get all the cpus to the average_load, so we don't
4032 * want to push ourselves above the average load, nor do we wish to
4033 * reduce the max loaded cpu below the average load, as either of these
4034 * actions would just result in more rebalancing later, and ping-pong
4035 * tasks around. Thus we look for the minimum possible imbalance.
4036 * Negative imbalances (*we* are more loaded than anyone else) will
4037 * be counted as no imbalance for these purposes -- we can't fix that
4038 * by pulling tasks to us. Be careful of negative numbers as they'll
4039 * appear as very large values with unsigned longs.
4041 if (sds
.max_load
<= sds
.busiest_load_per_task
)
4044 /* Looks like there is an imbalance. Compute it */
4045 calculate_imbalance(&sds
, this_cpu
, imbalance
);
4050 * There is no obvious imbalance. But check if we can do some balancing
4053 if (check_power_save_busiest_group(&sds
, this_cpu
, imbalance
))
4061 * find_busiest_queue - find the busiest runqueue among the cpus in group.
4064 find_busiest_queue(struct sched_group
*group
, enum cpu_idle_type idle
,
4065 unsigned long imbalance
, const struct cpumask
*cpus
)
4067 struct rq
*busiest
= NULL
, *rq
;
4068 unsigned long max_load
= 0;
4071 for_each_cpu(i
, sched_group_cpus(group
)) {
4072 unsigned long power
= power_of(i
);
4073 unsigned long capacity
= DIV_ROUND_CLOSEST(power
, SCHED_LOAD_SCALE
);
4076 if (!cpumask_test_cpu(i
, cpus
))
4080 wl
= weighted_cpuload(i
) * SCHED_LOAD_SCALE
;
4083 if (capacity
&& rq
->nr_running
== 1 && wl
> imbalance
)
4086 if (wl
> max_load
) {
4096 * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but
4097 * so long as it is large enough.
4099 #define MAX_PINNED_INTERVAL 512
4101 /* Working cpumask for load_balance and load_balance_newidle. */
4102 static DEFINE_PER_CPU(cpumask_var_t
, load_balance_tmpmask
);
4105 * Check this_cpu to ensure it is balanced within domain. Attempt to move
4106 * tasks if there is an imbalance.
4108 static int load_balance(int this_cpu
, struct rq
*this_rq
,
4109 struct sched_domain
*sd
, enum cpu_idle_type idle
,
4112 int ld_moved
, all_pinned
= 0, active_balance
= 0, sd_idle
= 0;
4113 struct sched_group
*group
;
4114 unsigned long imbalance
;
4116 unsigned long flags
;
4117 struct cpumask
*cpus
= __get_cpu_var(load_balance_tmpmask
);
4119 cpumask_copy(cpus
, cpu_active_mask
);
4122 * When power savings policy is enabled for the parent domain, idle
4123 * sibling can pick up load irrespective of busy siblings. In this case,
4124 * let the state of idle sibling percolate up as CPU_IDLE, instead of
4125 * portraying it as CPU_NOT_IDLE.
4127 if (idle
!= CPU_NOT_IDLE
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
4128 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
4131 schedstat_inc(sd
, lb_count
[idle
]);
4135 group
= find_busiest_group(sd
, this_cpu
, &imbalance
, idle
, &sd_idle
,
4142 schedstat_inc(sd
, lb_nobusyg
[idle
]);
4146 busiest
= find_busiest_queue(group
, idle
, imbalance
, cpus
);
4148 schedstat_inc(sd
, lb_nobusyq
[idle
]);
4152 BUG_ON(busiest
== this_rq
);
4154 schedstat_add(sd
, lb_imbalance
[idle
], imbalance
);
4157 if (busiest
->nr_running
> 1) {
4159 * Attempt to move tasks. If find_busiest_group has found
4160 * an imbalance but busiest->nr_running <= 1, the group is
4161 * still unbalanced. ld_moved simply stays zero, so it is
4162 * correctly treated as an imbalance.
4164 local_irq_save(flags
);
4165 double_rq_lock(this_rq
, busiest
);
4166 ld_moved
= move_tasks(this_rq
, this_cpu
, busiest
,
4167 imbalance
, sd
, idle
, &all_pinned
);
4168 double_rq_unlock(this_rq
, busiest
);
4169 local_irq_restore(flags
);
4172 * some other cpu did the load balance for us.
4174 if (ld_moved
&& this_cpu
!= smp_processor_id())
4175 resched_cpu(this_cpu
);
4177 /* All tasks on this runqueue were pinned by CPU affinity */
4178 if (unlikely(all_pinned
)) {
4179 cpumask_clear_cpu(cpu_of(busiest
), cpus
);
4180 if (!cpumask_empty(cpus
))
4187 schedstat_inc(sd
, lb_failed
[idle
]);
4188 sd
->nr_balance_failed
++;
4190 if (unlikely(sd
->nr_balance_failed
> sd
->cache_nice_tries
+2)) {
4192 raw_spin_lock_irqsave(&busiest
->lock
, flags
);
4194 /* don't kick the migration_thread, if the curr
4195 * task on busiest cpu can't be moved to this_cpu
4197 if (!cpumask_test_cpu(this_cpu
,
4198 &busiest
->curr
->cpus_allowed
)) {
4199 raw_spin_unlock_irqrestore(&busiest
->lock
,
4202 goto out_one_pinned
;
4205 if (!busiest
->active_balance
) {
4206 busiest
->active_balance
= 1;
4207 busiest
->push_cpu
= this_cpu
;
4210 raw_spin_unlock_irqrestore(&busiest
->lock
, flags
);
4212 wake_up_process(busiest
->migration_thread
);
4215 * We've kicked active balancing, reset the failure
4218 sd
->nr_balance_failed
= sd
->cache_nice_tries
+1;
4221 sd
->nr_balance_failed
= 0;
4223 if (likely(!active_balance
)) {
4224 /* We were unbalanced, so reset the balancing interval */
4225 sd
->balance_interval
= sd
->min_interval
;
4228 * If we've begun active balancing, start to back off. This
4229 * case may not be covered by the all_pinned logic if there
4230 * is only 1 task on the busy runqueue (because we don't call
4233 if (sd
->balance_interval
< sd
->max_interval
)
4234 sd
->balance_interval
*= 2;
4237 if (!ld_moved
&& !sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
4238 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
4244 schedstat_inc(sd
, lb_balanced
[idle
]);
4246 sd
->nr_balance_failed
= 0;
4249 /* tune up the balancing interval */
4250 if ((all_pinned
&& sd
->balance_interval
< MAX_PINNED_INTERVAL
) ||
4251 (sd
->balance_interval
< sd
->max_interval
))
4252 sd
->balance_interval
*= 2;
4254 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
4255 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
4266 * Check this_cpu to ensure it is balanced within domain. Attempt to move
4267 * tasks if there is an imbalance.
4269 * Called from schedule when this_rq is about to become idle (CPU_NEWLY_IDLE).
4270 * this_rq is locked.
4273 load_balance_newidle(int this_cpu
, struct rq
*this_rq
, struct sched_domain
*sd
)
4275 struct sched_group
*group
;
4276 struct rq
*busiest
= NULL
;
4277 unsigned long imbalance
;
4281 struct cpumask
*cpus
= __get_cpu_var(load_balance_tmpmask
);
4283 cpumask_copy(cpus
, cpu_active_mask
);
4286 * When power savings policy is enabled for the parent domain, idle
4287 * sibling can pick up load irrespective of busy siblings. In this case,
4288 * let the state of idle sibling percolate up as IDLE, instead of
4289 * portraying it as CPU_NOT_IDLE.
4291 if (sd
->flags
& SD_SHARE_CPUPOWER
&&
4292 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
4295 schedstat_inc(sd
, lb_count
[CPU_NEWLY_IDLE
]);
4297 update_shares_locked(this_rq
, sd
);
4298 group
= find_busiest_group(sd
, this_cpu
, &imbalance
, CPU_NEWLY_IDLE
,
4299 &sd_idle
, cpus
, NULL
);
4301 schedstat_inc(sd
, lb_nobusyg
[CPU_NEWLY_IDLE
]);
4305 busiest
= find_busiest_queue(group
, CPU_NEWLY_IDLE
, imbalance
, cpus
);
4307 schedstat_inc(sd
, lb_nobusyq
[CPU_NEWLY_IDLE
]);
4311 BUG_ON(busiest
== this_rq
);
4313 schedstat_add(sd
, lb_imbalance
[CPU_NEWLY_IDLE
], imbalance
);
4316 if (busiest
->nr_running
> 1) {
4317 /* Attempt to move tasks */
4318 double_lock_balance(this_rq
, busiest
);
4319 /* this_rq->clock is already updated */
4320 update_rq_clock(busiest
);
4321 ld_moved
= move_tasks(this_rq
, this_cpu
, busiest
,
4322 imbalance
, sd
, CPU_NEWLY_IDLE
,
4324 double_unlock_balance(this_rq
, busiest
);
4326 if (unlikely(all_pinned
)) {
4327 cpumask_clear_cpu(cpu_of(busiest
), cpus
);
4328 if (!cpumask_empty(cpus
))
4334 int active_balance
= 0;
4336 schedstat_inc(sd
, lb_failed
[CPU_NEWLY_IDLE
]);
4337 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
4338 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
4341 if (sched_mc_power_savings
< POWERSAVINGS_BALANCE_WAKEUP
)
4344 if (sd
->nr_balance_failed
++ < 2)
4348 * The only task running in a non-idle cpu can be moved to this
4349 * cpu in an attempt to completely freeup the other CPU
4350 * package. The same method used to move task in load_balance()
4351 * have been extended for load_balance_newidle() to speedup
4352 * consolidation at sched_mc=POWERSAVINGS_BALANCE_WAKEUP (2)
4354 * The package power saving logic comes from
4355 * find_busiest_group(). If there are no imbalance, then
4356 * f_b_g() will return NULL. However when sched_mc={1,2} then
4357 * f_b_g() will select a group from which a running task may be
4358 * pulled to this cpu in order to make the other package idle.
4359 * If there is no opportunity to make a package idle and if
4360 * there are no imbalance, then f_b_g() will return NULL and no
4361 * action will be taken in load_balance_newidle().
4363 * Under normal task pull operation due to imbalance, there
4364 * will be more than one task in the source run queue and
4365 * move_tasks() will succeed. ld_moved will be true and this
4366 * active balance code will not be triggered.
4369 /* Lock busiest in correct order while this_rq is held */
4370 double_lock_balance(this_rq
, busiest
);
4373 * don't kick the migration_thread, if the curr
4374 * task on busiest cpu can't be moved to this_cpu
4376 if (!cpumask_test_cpu(this_cpu
, &busiest
->curr
->cpus_allowed
)) {
4377 double_unlock_balance(this_rq
, busiest
);
4382 if (!busiest
->active_balance
) {
4383 busiest
->active_balance
= 1;
4384 busiest
->push_cpu
= this_cpu
;
4388 double_unlock_balance(this_rq
, busiest
);
4390 * Should not call ttwu while holding a rq->lock
4392 raw_spin_unlock(&this_rq
->lock
);
4394 wake_up_process(busiest
->migration_thread
);
4395 raw_spin_lock(&this_rq
->lock
);
4398 sd
->nr_balance_failed
= 0;
4400 update_shares_locked(this_rq
, sd
);
4404 schedstat_inc(sd
, lb_balanced
[CPU_NEWLY_IDLE
]);
4405 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
4406 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
4408 sd
->nr_balance_failed
= 0;
4414 * idle_balance is called by schedule() if this_cpu is about to become
4415 * idle. Attempts to pull tasks from other CPUs.
4417 static void idle_balance(int this_cpu
, struct rq
*this_rq
)
4419 struct sched_domain
*sd
;
4420 int pulled_task
= 0;
4421 unsigned long next_balance
= jiffies
+ HZ
;
4423 this_rq
->idle_stamp
= this_rq
->clock
;
4425 if (this_rq
->avg_idle
< sysctl_sched_migration_cost
)
4428 for_each_domain(this_cpu
, sd
) {
4429 unsigned long interval
;
4431 if (!(sd
->flags
& SD_LOAD_BALANCE
))
4434 if (sd
->flags
& SD_BALANCE_NEWIDLE
)
4435 /* If we've pulled tasks over stop searching: */
4436 pulled_task
= load_balance_newidle(this_cpu
, this_rq
,
4439 interval
= msecs_to_jiffies(sd
->balance_interval
);
4440 if (time_after(next_balance
, sd
->last_balance
+ interval
))
4441 next_balance
= sd
->last_balance
+ interval
;
4443 this_rq
->idle_stamp
= 0;
4447 if (pulled_task
|| time_after(jiffies
, this_rq
->next_balance
)) {
4449 * We are going idle. next_balance may be set based on
4450 * a busy processor. So reset next_balance.
4452 this_rq
->next_balance
= next_balance
;
4457 * active_load_balance is run by migration threads. It pushes running tasks
4458 * off the busiest CPU onto idle CPUs. It requires at least 1 task to be
4459 * running on each physical CPU where possible, and avoids physical /
4460 * logical imbalances.
4462 * Called with busiest_rq locked.
4464 static void active_load_balance(struct rq
*busiest_rq
, int busiest_cpu
)
4466 int target_cpu
= busiest_rq
->push_cpu
;
4467 struct sched_domain
*sd
;
4468 struct rq
*target_rq
;
4470 /* Is there any task to move? */
4471 if (busiest_rq
->nr_running
<= 1)
4474 target_rq
= cpu_rq(target_cpu
);
4477 * This condition is "impossible", if it occurs
4478 * we need to fix it. Originally reported by
4479 * Bjorn Helgaas on a 128-cpu setup.
4481 BUG_ON(busiest_rq
== target_rq
);
4483 /* move a task from busiest_rq to target_rq */
4484 double_lock_balance(busiest_rq
, target_rq
);
4485 update_rq_clock(busiest_rq
);
4486 update_rq_clock(target_rq
);
4488 /* Search for an sd spanning us and the target CPU. */
4489 for_each_domain(target_cpu
, sd
) {
4490 if ((sd
->flags
& SD_LOAD_BALANCE
) &&
4491 cpumask_test_cpu(busiest_cpu
, sched_domain_span(sd
)))
4496 schedstat_inc(sd
, alb_count
);
4498 if (move_one_task(target_rq
, target_cpu
, busiest_rq
,
4500 schedstat_inc(sd
, alb_pushed
);
4502 schedstat_inc(sd
, alb_failed
);
4504 double_unlock_balance(busiest_rq
, target_rq
);
4509 atomic_t load_balancer
;
4510 cpumask_var_t cpu_mask
;
4511 cpumask_var_t ilb_grp_nohz_mask
;
4512 } nohz ____cacheline_aligned
= {
4513 .load_balancer
= ATOMIC_INIT(-1),
4516 int get_nohz_load_balancer(void)
4518 return atomic_read(&nohz
.load_balancer
);
4521 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
4523 * lowest_flag_domain - Return lowest sched_domain containing flag.
4524 * @cpu: The cpu whose lowest level of sched domain is to
4526 * @flag: The flag to check for the lowest sched_domain
4527 * for the given cpu.
4529 * Returns the lowest sched_domain of a cpu which contains the given flag.
4531 static inline struct sched_domain
*lowest_flag_domain(int cpu
, int flag
)
4533 struct sched_domain
*sd
;
4535 for_each_domain(cpu
, sd
)
4536 if (sd
&& (sd
->flags
& flag
))
4543 * for_each_flag_domain - Iterates over sched_domains containing the flag.
4544 * @cpu: The cpu whose domains we're iterating over.
4545 * @sd: variable holding the value of the power_savings_sd
4547 * @flag: The flag to filter the sched_domains to be iterated.
4549 * Iterates over all the scheduler domains for a given cpu that has the 'flag'
4550 * set, starting from the lowest sched_domain to the highest.
4552 #define for_each_flag_domain(cpu, sd, flag) \
4553 for (sd = lowest_flag_domain(cpu, flag); \
4554 (sd && (sd->flags & flag)); sd = sd->parent)
4557 * is_semi_idle_group - Checks if the given sched_group is semi-idle.
4558 * @ilb_group: group to be checked for semi-idleness
4560 * Returns: 1 if the group is semi-idle. 0 otherwise.
4562 * We define a sched_group to be semi idle if it has atleast one idle-CPU
4563 * and atleast one non-idle CPU. This helper function checks if the given
4564 * sched_group is semi-idle or not.
4566 static inline int is_semi_idle_group(struct sched_group
*ilb_group
)
4568 cpumask_and(nohz
.ilb_grp_nohz_mask
, nohz
.cpu_mask
,
4569 sched_group_cpus(ilb_group
));
4572 * A sched_group is semi-idle when it has atleast one busy cpu
4573 * and atleast one idle cpu.
4575 if (cpumask_empty(nohz
.ilb_grp_nohz_mask
))
4578 if (cpumask_equal(nohz
.ilb_grp_nohz_mask
, sched_group_cpus(ilb_group
)))
4584 * find_new_ilb - Finds the optimum idle load balancer for nomination.
4585 * @cpu: The cpu which is nominating a new idle_load_balancer.
4587 * Returns: Returns the id of the idle load balancer if it exists,
4588 * Else, returns >= nr_cpu_ids.
4590 * This algorithm picks the idle load balancer such that it belongs to a
4591 * semi-idle powersavings sched_domain. The idea is to try and avoid
4592 * completely idle packages/cores just for the purpose of idle load balancing
4593 * when there are other idle cpu's which are better suited for that job.
4595 static int find_new_ilb(int cpu
)
4597 struct sched_domain
*sd
;
4598 struct sched_group
*ilb_group
;
4601 * Have idle load balancer selection from semi-idle packages only
4602 * when power-aware load balancing is enabled
4604 if (!(sched_smt_power_savings
|| sched_mc_power_savings
))
4608 * Optimize for the case when we have no idle CPUs or only one
4609 * idle CPU. Don't walk the sched_domain hierarchy in such cases
4611 if (cpumask_weight(nohz
.cpu_mask
) < 2)
4614 for_each_flag_domain(cpu
, sd
, SD_POWERSAVINGS_BALANCE
) {
4615 ilb_group
= sd
->groups
;
4618 if (is_semi_idle_group(ilb_group
))
4619 return cpumask_first(nohz
.ilb_grp_nohz_mask
);
4621 ilb_group
= ilb_group
->next
;
4623 } while (ilb_group
!= sd
->groups
);
4627 return cpumask_first(nohz
.cpu_mask
);
4629 #else /* (CONFIG_SCHED_MC || CONFIG_SCHED_SMT) */
4630 static inline int find_new_ilb(int call_cpu
)
4632 return cpumask_first(nohz
.cpu_mask
);
4637 * This routine will try to nominate the ilb (idle load balancing)
4638 * owner among the cpus whose ticks are stopped. ilb owner will do the idle
4639 * load balancing on behalf of all those cpus. If all the cpus in the system
4640 * go into this tickless mode, then there will be no ilb owner (as there is
4641 * no need for one) and all the cpus will sleep till the next wakeup event
4644 * For the ilb owner, tick is not stopped. And this tick will be used
4645 * for idle load balancing. ilb owner will still be part of
4648 * While stopping the tick, this cpu will become the ilb owner if there
4649 * is no other owner. And will be the owner till that cpu becomes busy
4650 * or if all cpus in the system stop their ticks at which point
4651 * there is no need for ilb owner.
4653 * When the ilb owner becomes busy, it nominates another owner, during the
4654 * next busy scheduler_tick()
4656 int select_nohz_load_balancer(int stop_tick
)
4658 int cpu
= smp_processor_id();
4661 cpu_rq(cpu
)->in_nohz_recently
= 1;
4663 if (!cpu_active(cpu
)) {
4664 if (atomic_read(&nohz
.load_balancer
) != cpu
)
4668 * If we are going offline and still the leader,
4671 if (atomic_cmpxchg(&nohz
.load_balancer
, cpu
, -1) != cpu
)
4677 cpumask_set_cpu(cpu
, nohz
.cpu_mask
);
4679 /* time for ilb owner also to sleep */
4680 if (cpumask_weight(nohz
.cpu_mask
) == num_active_cpus()) {
4681 if (atomic_read(&nohz
.load_balancer
) == cpu
)
4682 atomic_set(&nohz
.load_balancer
, -1);
4686 if (atomic_read(&nohz
.load_balancer
) == -1) {
4687 /* make me the ilb owner */
4688 if (atomic_cmpxchg(&nohz
.load_balancer
, -1, cpu
) == -1)
4690 } else if (atomic_read(&nohz
.load_balancer
) == cpu
) {
4693 if (!(sched_smt_power_savings
||
4694 sched_mc_power_savings
))
4697 * Check to see if there is a more power-efficient
4700 new_ilb
= find_new_ilb(cpu
);
4701 if (new_ilb
< nr_cpu_ids
&& new_ilb
!= cpu
) {
4702 atomic_set(&nohz
.load_balancer
, -1);
4703 resched_cpu(new_ilb
);
4709 if (!cpumask_test_cpu(cpu
, nohz
.cpu_mask
))
4712 cpumask_clear_cpu(cpu
, nohz
.cpu_mask
);
4714 if (atomic_read(&nohz
.load_balancer
) == cpu
)
4715 if (atomic_cmpxchg(&nohz
.load_balancer
, cpu
, -1) != cpu
)
4722 static DEFINE_SPINLOCK(balancing
);
4725 * It checks each scheduling domain to see if it is due to be balanced,
4726 * and initiates a balancing operation if so.
4728 * Balancing parameters are set up in arch_init_sched_domains.
4730 static void rebalance_domains(int cpu
, enum cpu_idle_type idle
)
4733 struct rq
*rq
= cpu_rq(cpu
);
4734 unsigned long interval
;
4735 struct sched_domain
*sd
;
4736 /* Earliest time when we have to do rebalance again */
4737 unsigned long next_balance
= jiffies
+ 60*HZ
;
4738 int update_next_balance
= 0;
4741 for_each_domain(cpu
, sd
) {
4742 if (!(sd
->flags
& SD_LOAD_BALANCE
))
4745 interval
= sd
->balance_interval
;
4746 if (idle
!= CPU_IDLE
)
4747 interval
*= sd
->busy_factor
;
4749 /* scale ms to jiffies */
4750 interval
= msecs_to_jiffies(interval
);
4751 if (unlikely(!interval
))
4753 if (interval
> HZ
*NR_CPUS
/10)
4754 interval
= HZ
*NR_CPUS
/10;
4756 need_serialize
= sd
->flags
& SD_SERIALIZE
;
4758 if (need_serialize
) {
4759 if (!spin_trylock(&balancing
))
4763 if (time_after_eq(jiffies
, sd
->last_balance
+ interval
)) {
4764 if (load_balance(cpu
, rq
, sd
, idle
, &balance
)) {
4766 * We've pulled tasks over so either we're no
4767 * longer idle, or one of our SMT siblings is
4770 idle
= CPU_NOT_IDLE
;
4772 sd
->last_balance
= jiffies
;
4775 spin_unlock(&balancing
);
4777 if (time_after(next_balance
, sd
->last_balance
+ interval
)) {
4778 next_balance
= sd
->last_balance
+ interval
;
4779 update_next_balance
= 1;
4783 * Stop the load balance at this level. There is another
4784 * CPU in our sched group which is doing load balancing more
4792 * next_balance will be updated only when there is a need.
4793 * When the cpu is attached to null domain for ex, it will not be
4796 if (likely(update_next_balance
))
4797 rq
->next_balance
= next_balance
;
4801 * run_rebalance_domains is triggered when needed from the scheduler tick.
4802 * In CONFIG_NO_HZ case, the idle load balance owner will do the
4803 * rebalancing for all the cpus for whom scheduler ticks are stopped.
4805 static void run_rebalance_domains(struct softirq_action
*h
)
4807 int this_cpu
= smp_processor_id();
4808 struct rq
*this_rq
= cpu_rq(this_cpu
);
4809 enum cpu_idle_type idle
= this_rq
->idle_at_tick
?
4810 CPU_IDLE
: CPU_NOT_IDLE
;
4812 rebalance_domains(this_cpu
, idle
);
4816 * If this cpu is the owner for idle load balancing, then do the
4817 * balancing on behalf of the other idle cpus whose ticks are
4820 if (this_rq
->idle_at_tick
&&
4821 atomic_read(&nohz
.load_balancer
) == this_cpu
) {
4825 for_each_cpu(balance_cpu
, nohz
.cpu_mask
) {
4826 if (balance_cpu
== this_cpu
)
4830 * If this cpu gets work to do, stop the load balancing
4831 * work being done for other cpus. Next load
4832 * balancing owner will pick it up.
4837 rebalance_domains(balance_cpu
, CPU_IDLE
);
4839 rq
= cpu_rq(balance_cpu
);
4840 if (time_after(this_rq
->next_balance
, rq
->next_balance
))
4841 this_rq
->next_balance
= rq
->next_balance
;
4847 static inline int on_null_domain(int cpu
)
4849 return !rcu_dereference(cpu_rq(cpu
)->sd
);
4853 * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing.
4855 * In case of CONFIG_NO_HZ, this is the place where we nominate a new
4856 * idle load balancing owner or decide to stop the periodic load balancing,
4857 * if the whole system is idle.
4859 static inline void trigger_load_balance(struct rq
*rq
, int cpu
)
4863 * If we were in the nohz mode recently and busy at the current
4864 * scheduler tick, then check if we need to nominate new idle
4867 if (rq
->in_nohz_recently
&& !rq
->idle_at_tick
) {
4868 rq
->in_nohz_recently
= 0;
4870 if (atomic_read(&nohz
.load_balancer
) == cpu
) {
4871 cpumask_clear_cpu(cpu
, nohz
.cpu_mask
);
4872 atomic_set(&nohz
.load_balancer
, -1);
4875 if (atomic_read(&nohz
.load_balancer
) == -1) {
4876 int ilb
= find_new_ilb(cpu
);
4878 if (ilb
< nr_cpu_ids
)
4884 * If this cpu is idle and doing idle load balancing for all the
4885 * cpus with ticks stopped, is it time for that to stop?
4887 if (rq
->idle_at_tick
&& atomic_read(&nohz
.load_balancer
) == cpu
&&
4888 cpumask_weight(nohz
.cpu_mask
) == num_online_cpus()) {
4894 * If this cpu is idle and the idle load balancing is done by
4895 * someone else, then no need raise the SCHED_SOFTIRQ
4897 if (rq
->idle_at_tick
&& atomic_read(&nohz
.load_balancer
) != cpu
&&
4898 cpumask_test_cpu(cpu
, nohz
.cpu_mask
))
4901 /* Don't need to rebalance while attached to NULL domain */
4902 if (time_after_eq(jiffies
, rq
->next_balance
) &&
4903 likely(!on_null_domain(cpu
)))
4904 raise_softirq(SCHED_SOFTIRQ
);
4907 #else /* CONFIG_SMP */
4910 * on UP we do not need to balance between CPUs:
4912 static inline void idle_balance(int cpu
, struct rq
*rq
)
4918 DEFINE_PER_CPU(struct kernel_stat
, kstat
);
4920 EXPORT_PER_CPU_SYMBOL(kstat
);
4923 * Return any ns on the sched_clock that have not yet been accounted in
4924 * @p in case that task is currently running.
4926 * Called with task_rq_lock() held on @rq.
4928 static u64
do_task_delta_exec(struct task_struct
*p
, struct rq
*rq
)
4932 if (task_current(rq
, p
)) {
4933 update_rq_clock(rq
);
4934 ns
= rq
->clock
- p
->se
.exec_start
;
4942 unsigned long long task_delta_exec(struct task_struct
*p
)
4944 unsigned long flags
;
4948 rq
= task_rq_lock(p
, &flags
);
4949 ns
= do_task_delta_exec(p
, rq
);
4950 task_rq_unlock(rq
, &flags
);
4956 * Return accounted runtime for the task.
4957 * In case the task is currently running, return the runtime plus current's
4958 * pending runtime that have not been accounted yet.
4960 unsigned long long task_sched_runtime(struct task_struct
*p
)
4962 unsigned long flags
;
4966 rq
= task_rq_lock(p
, &flags
);
4967 ns
= p
->se
.sum_exec_runtime
+ do_task_delta_exec(p
, rq
);
4968 task_rq_unlock(rq
, &flags
);
4974 * Return sum_exec_runtime for the thread group.
4975 * In case the task is currently running, return the sum plus current's
4976 * pending runtime that have not been accounted yet.
4978 * Note that the thread group might have other running tasks as well,
4979 * so the return value not includes other pending runtime that other
4980 * running tasks might have.
4982 unsigned long long thread_group_sched_runtime(struct task_struct
*p
)
4984 struct task_cputime totals
;
4985 unsigned long flags
;
4989 rq
= task_rq_lock(p
, &flags
);
4990 thread_group_cputime(p
, &totals
);
4991 ns
= totals
.sum_exec_runtime
+ do_task_delta_exec(p
, rq
);
4992 task_rq_unlock(rq
, &flags
);
4998 * Account user cpu time to a process.
4999 * @p: the process that the cpu time gets accounted to
5000 * @cputime: the cpu time spent in user space since the last update
5001 * @cputime_scaled: cputime scaled by cpu frequency
5003 void account_user_time(struct task_struct
*p
, cputime_t cputime
,
5004 cputime_t cputime_scaled
)
5006 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
5009 /* Add user time to process. */
5010 p
->utime
= cputime_add(p
->utime
, cputime
);
5011 p
->utimescaled
= cputime_add(p
->utimescaled
, cputime_scaled
);
5012 account_group_user_time(p
, cputime
);
5014 /* Add user time to cpustat. */
5015 tmp
= cputime_to_cputime64(cputime
);
5016 if (TASK_NICE(p
) > 0)
5017 cpustat
->nice
= cputime64_add(cpustat
->nice
, tmp
);
5019 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
5021 cpuacct_update_stats(p
, CPUACCT_STAT_USER
, cputime
);
5022 /* Account for user time used */
5023 acct_update_integrals(p
);
5027 * Account guest cpu time to a process.
5028 * @p: the process that the cpu time gets accounted to
5029 * @cputime: the cpu time spent in virtual machine since the last update
5030 * @cputime_scaled: cputime scaled by cpu frequency
5032 static void account_guest_time(struct task_struct
*p
, cputime_t cputime
,
5033 cputime_t cputime_scaled
)
5036 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
5038 tmp
= cputime_to_cputime64(cputime
);
5040 /* Add guest time to process. */
5041 p
->utime
= cputime_add(p
->utime
, cputime
);
5042 p
->utimescaled
= cputime_add(p
->utimescaled
, cputime_scaled
);
5043 account_group_user_time(p
, cputime
);
5044 p
->gtime
= cputime_add(p
->gtime
, cputime
);
5046 /* Add guest time to cpustat. */
5047 if (TASK_NICE(p
) > 0) {
5048 cpustat
->nice
= cputime64_add(cpustat
->nice
, tmp
);
5049 cpustat
->guest_nice
= cputime64_add(cpustat
->guest_nice
, tmp
);
5051 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
5052 cpustat
->guest
= cputime64_add(cpustat
->guest
, tmp
);
5057 * Account system cpu time to a process.
5058 * @p: the process that the cpu time gets accounted to
5059 * @hardirq_offset: the offset to subtract from hardirq_count()
5060 * @cputime: the cpu time spent in kernel space since the last update
5061 * @cputime_scaled: cputime scaled by cpu frequency
5063 void account_system_time(struct task_struct
*p
, int hardirq_offset
,
5064 cputime_t cputime
, cputime_t cputime_scaled
)
5066 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
5069 if ((p
->flags
& PF_VCPU
) && (irq_count() - hardirq_offset
== 0)) {
5070 account_guest_time(p
, cputime
, cputime_scaled
);
5074 /* Add system time to process. */
5075 p
->stime
= cputime_add(p
->stime
, cputime
);
5076 p
->stimescaled
= cputime_add(p
->stimescaled
, cputime_scaled
);
5077 account_group_system_time(p
, cputime
);
5079 /* Add system time to cpustat. */
5080 tmp
= cputime_to_cputime64(cputime
);
5081 if (hardirq_count() - hardirq_offset
)
5082 cpustat
->irq
= cputime64_add(cpustat
->irq
, tmp
);
5083 else if (softirq_count())
5084 cpustat
->softirq
= cputime64_add(cpustat
->softirq
, tmp
);
5086 cpustat
->system
= cputime64_add(cpustat
->system
, tmp
);
5088 cpuacct_update_stats(p
, CPUACCT_STAT_SYSTEM
, cputime
);
5090 /* Account for system time used */
5091 acct_update_integrals(p
);
5095 * Account for involuntary wait time.
5096 * @steal: the cpu time spent in involuntary wait
5098 void account_steal_time(cputime_t cputime
)
5100 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
5101 cputime64_t cputime64
= cputime_to_cputime64(cputime
);
5103 cpustat
->steal
= cputime64_add(cpustat
->steal
, cputime64
);
5107 * Account for idle time.
5108 * @cputime: the cpu time spent in idle wait
5110 void account_idle_time(cputime_t cputime
)
5112 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
5113 cputime64_t cputime64
= cputime_to_cputime64(cputime
);
5114 struct rq
*rq
= this_rq();
5116 if (atomic_read(&rq
->nr_iowait
) > 0)
5117 cpustat
->iowait
= cputime64_add(cpustat
->iowait
, cputime64
);
5119 cpustat
->idle
= cputime64_add(cpustat
->idle
, cputime64
);
5122 #ifndef CONFIG_VIRT_CPU_ACCOUNTING
5125 * Account a single tick of cpu time.
5126 * @p: the process that the cpu time gets accounted to
5127 * @user_tick: indicates if the tick is a user or a system tick
5129 void account_process_tick(struct task_struct
*p
, int user_tick
)
5131 cputime_t one_jiffy_scaled
= cputime_to_scaled(cputime_one_jiffy
);
5132 struct rq
*rq
= this_rq();
5135 account_user_time(p
, cputime_one_jiffy
, one_jiffy_scaled
);
5136 else if ((p
!= rq
->idle
) || (irq_count() != HARDIRQ_OFFSET
))
5137 account_system_time(p
, HARDIRQ_OFFSET
, cputime_one_jiffy
,
5140 account_idle_time(cputime_one_jiffy
);
5144 * Account multiple ticks of steal time.
5145 * @p: the process from which the cpu time has been stolen
5146 * @ticks: number of stolen ticks
5148 void account_steal_ticks(unsigned long ticks
)
5150 account_steal_time(jiffies_to_cputime(ticks
));
5154 * Account multiple ticks of idle time.
5155 * @ticks: number of stolen ticks
5157 void account_idle_ticks(unsigned long ticks
)
5159 account_idle_time(jiffies_to_cputime(ticks
));
5165 * Use precise platform statistics if available:
5167 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
5168 void task_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
5174 void thread_group_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
5176 struct task_cputime cputime
;
5178 thread_group_cputime(p
, &cputime
);
5180 *ut
= cputime
.utime
;
5181 *st
= cputime
.stime
;
5185 #ifndef nsecs_to_cputime
5186 # define nsecs_to_cputime(__nsecs) nsecs_to_jiffies(__nsecs)
5189 void task_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
5191 cputime_t rtime
, utime
= p
->utime
, total
= cputime_add(utime
, p
->stime
);
5194 * Use CFS's precise accounting:
5196 rtime
= nsecs_to_cputime(p
->se
.sum_exec_runtime
);
5201 temp
= (u64
)(rtime
* utime
);
5202 do_div(temp
, total
);
5203 utime
= (cputime_t
)temp
;
5208 * Compare with previous values, to keep monotonicity:
5210 p
->prev_utime
= max(p
->prev_utime
, utime
);
5211 p
->prev_stime
= max(p
->prev_stime
, cputime_sub(rtime
, p
->prev_utime
));
5213 *ut
= p
->prev_utime
;
5214 *st
= p
->prev_stime
;
5218 * Must be called with siglock held.
5220 void thread_group_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
5222 struct signal_struct
*sig
= p
->signal
;
5223 struct task_cputime cputime
;
5224 cputime_t rtime
, utime
, total
;
5226 thread_group_cputime(p
, &cputime
);
5228 total
= cputime_add(cputime
.utime
, cputime
.stime
);
5229 rtime
= nsecs_to_cputime(cputime
.sum_exec_runtime
);
5234 temp
= (u64
)(rtime
* cputime
.utime
);
5235 do_div(temp
, total
);
5236 utime
= (cputime_t
)temp
;
5240 sig
->prev_utime
= max(sig
->prev_utime
, utime
);
5241 sig
->prev_stime
= max(sig
->prev_stime
,
5242 cputime_sub(rtime
, sig
->prev_utime
));
5244 *ut
= sig
->prev_utime
;
5245 *st
= sig
->prev_stime
;
5250 * This function gets called by the timer code, with HZ frequency.
5251 * We call it with interrupts disabled.
5253 * It also gets called by the fork code, when changing the parent's
5256 void scheduler_tick(void)
5258 int cpu
= smp_processor_id();
5259 struct rq
*rq
= cpu_rq(cpu
);
5260 struct task_struct
*curr
= rq
->curr
;
5264 raw_spin_lock(&rq
->lock
);
5265 update_rq_clock(rq
);
5266 update_cpu_load(rq
);
5267 curr
->sched_class
->task_tick(rq
, curr
, 0);
5268 raw_spin_unlock(&rq
->lock
);
5270 perf_event_task_tick(curr
, cpu
);
5273 rq
->idle_at_tick
= idle_cpu(cpu
);
5274 trigger_load_balance(rq
, cpu
);
5278 notrace
unsigned long get_parent_ip(unsigned long addr
)
5280 if (in_lock_functions(addr
)) {
5281 addr
= CALLER_ADDR2
;
5282 if (in_lock_functions(addr
))
5283 addr
= CALLER_ADDR3
;
5288 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
5289 defined(CONFIG_PREEMPT_TRACER))
5291 void __kprobes
add_preempt_count(int val
)
5293 #ifdef CONFIG_DEBUG_PREEMPT
5297 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
5300 preempt_count() += val
;
5301 #ifdef CONFIG_DEBUG_PREEMPT
5303 * Spinlock count overflowing soon?
5305 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK
) >=
5308 if (preempt_count() == val
)
5309 trace_preempt_off(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
5311 EXPORT_SYMBOL(add_preempt_count
);
5313 void __kprobes
sub_preempt_count(int val
)
5315 #ifdef CONFIG_DEBUG_PREEMPT
5319 if (DEBUG_LOCKS_WARN_ON(val
> preempt_count()))
5322 * Is the spinlock portion underflowing?
5324 if (DEBUG_LOCKS_WARN_ON((val
< PREEMPT_MASK
) &&
5325 !(preempt_count() & PREEMPT_MASK
)))
5329 if (preempt_count() == val
)
5330 trace_preempt_on(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
5331 preempt_count() -= val
;
5333 EXPORT_SYMBOL(sub_preempt_count
);
5338 * Print scheduling while atomic bug:
5340 static noinline
void __schedule_bug(struct task_struct
*prev
)
5342 struct pt_regs
*regs
= get_irq_regs();
5344 pr_err("BUG: scheduling while atomic: %s/%d/0x%08x\n",
5345 prev
->comm
, prev
->pid
, preempt_count());
5347 debug_show_held_locks(prev
);
5349 if (irqs_disabled())
5350 print_irqtrace_events(prev
);
5359 * Various schedule()-time debugging checks and statistics:
5361 static inline void schedule_debug(struct task_struct
*prev
)
5364 * Test if we are atomic. Since do_exit() needs to call into
5365 * schedule() atomically, we ignore that path for now.
5366 * Otherwise, whine if we are scheduling when we should not be.
5368 if (unlikely(in_atomic_preempt_off() && !prev
->exit_state
))
5369 __schedule_bug(prev
);
5371 profile_hit(SCHED_PROFILING
, __builtin_return_address(0));
5373 schedstat_inc(this_rq(), sched_count
);
5374 #ifdef CONFIG_SCHEDSTATS
5375 if (unlikely(prev
->lock_depth
>= 0)) {
5376 schedstat_inc(this_rq(), bkl_count
);
5377 schedstat_inc(prev
, sched_info
.bkl_count
);
5382 static void put_prev_task(struct rq
*rq
, struct task_struct
*prev
)
5384 if (prev
->state
== TASK_RUNNING
) {
5385 u64 runtime
= prev
->se
.sum_exec_runtime
;
5387 runtime
-= prev
->se
.prev_sum_exec_runtime
;
5388 runtime
= min_t(u64
, runtime
, 2*sysctl_sched_migration_cost
);
5391 * In order to avoid avg_overlap growing stale when we are
5392 * indeed overlapping and hence not getting put to sleep, grow
5393 * the avg_overlap on preemption.
5395 * We use the average preemption runtime because that
5396 * correlates to the amount of cache footprint a task can
5399 update_avg(&prev
->se
.avg_overlap
, runtime
);
5401 prev
->sched_class
->put_prev_task(rq
, prev
);
5405 * Pick up the highest-prio task:
5407 static inline struct task_struct
*
5408 pick_next_task(struct rq
*rq
)
5410 const struct sched_class
*class;
5411 struct task_struct
*p
;
5414 * Optimization: we know that if all tasks are in
5415 * the fair class we can call that function directly:
5417 if (likely(rq
->nr_running
== rq
->cfs
.nr_running
)) {
5418 p
= fair_sched_class
.pick_next_task(rq
);
5423 class = sched_class_highest
;
5425 p
= class->pick_next_task(rq
);
5429 * Will never be NULL as the idle class always
5430 * returns a non-NULL p:
5432 class = class->next
;
5437 * schedule() is the main scheduler function.
5439 asmlinkage
void __sched
schedule(void)
5441 struct task_struct
*prev
, *next
;
5442 unsigned long *switch_count
;
5448 cpu
= smp_processor_id();
5452 switch_count
= &prev
->nivcsw
;
5454 release_kernel_lock(prev
);
5455 need_resched_nonpreemptible
:
5457 schedule_debug(prev
);
5459 if (sched_feat(HRTICK
))
5462 raw_spin_lock_irq(&rq
->lock
);
5463 update_rq_clock(rq
);
5464 clear_tsk_need_resched(prev
);
5466 if (prev
->state
&& !(preempt_count() & PREEMPT_ACTIVE
)) {
5467 if (unlikely(signal_pending_state(prev
->state
, prev
)))
5468 prev
->state
= TASK_RUNNING
;
5470 deactivate_task(rq
, prev
, 1);
5471 switch_count
= &prev
->nvcsw
;
5474 pre_schedule(rq
, prev
);
5476 if (unlikely(!rq
->nr_running
))
5477 idle_balance(cpu
, rq
);
5479 put_prev_task(rq
, prev
);
5480 next
= pick_next_task(rq
);
5482 if (likely(prev
!= next
)) {
5483 sched_info_switch(prev
, next
);
5484 perf_event_task_sched_out(prev
, next
, cpu
);
5490 context_switch(rq
, prev
, next
); /* unlocks the rq */
5492 * the context switch might have flipped the stack from under
5493 * us, hence refresh the local variables.
5495 cpu
= smp_processor_id();
5498 raw_spin_unlock_irq(&rq
->lock
);
5502 if (unlikely(reacquire_kernel_lock(current
) < 0))
5503 goto need_resched_nonpreemptible
;
5505 preempt_enable_no_resched();
5509 EXPORT_SYMBOL(schedule
);
5511 #ifdef CONFIG_MUTEX_SPIN_ON_OWNER
5513 * Look out! "owner" is an entirely speculative pointer
5514 * access and not reliable.
5516 int mutex_spin_on_owner(struct mutex
*lock
, struct thread_info
*owner
)
5521 if (!sched_feat(OWNER_SPIN
))
5524 #ifdef CONFIG_DEBUG_PAGEALLOC
5526 * Need to access the cpu field knowing that
5527 * DEBUG_PAGEALLOC could have unmapped it if
5528 * the mutex owner just released it and exited.
5530 if (probe_kernel_address(&owner
->cpu
, cpu
))
5537 * Even if the access succeeded (likely case),
5538 * the cpu field may no longer be valid.
5540 if (cpu
>= nr_cpumask_bits
)
5544 * We need to validate that we can do a
5545 * get_cpu() and that we have the percpu area.
5547 if (!cpu_online(cpu
))
5554 * Owner changed, break to re-assess state.
5556 if (lock
->owner
!= owner
)
5560 * Is that owner really running on that cpu?
5562 if (task_thread_info(rq
->curr
) != owner
|| need_resched())
5572 #ifdef CONFIG_PREEMPT
5574 * this is the entry point to schedule() from in-kernel preemption
5575 * off of preempt_enable. Kernel preemptions off return from interrupt
5576 * occur there and call schedule directly.
5578 asmlinkage
void __sched
preempt_schedule(void)
5580 struct thread_info
*ti
= current_thread_info();
5583 * If there is a non-zero preempt_count or interrupts are disabled,
5584 * we do not want to preempt the current task. Just return..
5586 if (likely(ti
->preempt_count
|| irqs_disabled()))
5590 add_preempt_count(PREEMPT_ACTIVE
);
5592 sub_preempt_count(PREEMPT_ACTIVE
);
5595 * Check again in case we missed a preemption opportunity
5596 * between schedule and now.
5599 } while (need_resched());
5601 EXPORT_SYMBOL(preempt_schedule
);
5604 * this is the entry point to schedule() from kernel preemption
5605 * off of irq context.
5606 * Note, that this is called and return with irqs disabled. This will
5607 * protect us against recursive calling from irq.
5609 asmlinkage
void __sched
preempt_schedule_irq(void)
5611 struct thread_info
*ti
= current_thread_info();
5613 /* Catch callers which need to be fixed */
5614 BUG_ON(ti
->preempt_count
|| !irqs_disabled());
5617 add_preempt_count(PREEMPT_ACTIVE
);
5620 local_irq_disable();
5621 sub_preempt_count(PREEMPT_ACTIVE
);
5624 * Check again in case we missed a preemption opportunity
5625 * between schedule and now.
5628 } while (need_resched());
5631 #endif /* CONFIG_PREEMPT */
5633 int default_wake_function(wait_queue_t
*curr
, unsigned mode
, int wake_flags
,
5636 return try_to_wake_up(curr
->private, mode
, wake_flags
);
5638 EXPORT_SYMBOL(default_wake_function
);
5641 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
5642 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
5643 * number) then we wake all the non-exclusive tasks and one exclusive task.
5645 * There are circumstances in which we can try to wake a task which has already
5646 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
5647 * zero in this (rare) case, and we handle it by continuing to scan the queue.
5649 static void __wake_up_common(wait_queue_head_t
*q
, unsigned int mode
,
5650 int nr_exclusive
, int wake_flags
, void *key
)
5652 wait_queue_t
*curr
, *next
;
5654 list_for_each_entry_safe(curr
, next
, &q
->task_list
, task_list
) {
5655 unsigned flags
= curr
->flags
;
5657 if (curr
->func(curr
, mode
, wake_flags
, key
) &&
5658 (flags
& WQ_FLAG_EXCLUSIVE
) && !--nr_exclusive
)
5664 * __wake_up - wake up threads blocked on a waitqueue.
5666 * @mode: which threads
5667 * @nr_exclusive: how many wake-one or wake-many threads to wake up
5668 * @key: is directly passed to the wakeup function
5670 * It may be assumed that this function implies a write memory barrier before
5671 * changing the task state if and only if any tasks are woken up.
5673 void __wake_up(wait_queue_head_t
*q
, unsigned int mode
,
5674 int nr_exclusive
, void *key
)
5676 unsigned long flags
;
5678 spin_lock_irqsave(&q
->lock
, flags
);
5679 __wake_up_common(q
, mode
, nr_exclusive
, 0, key
);
5680 spin_unlock_irqrestore(&q
->lock
, flags
);
5682 EXPORT_SYMBOL(__wake_up
);
5685 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
5687 void __wake_up_locked(wait_queue_head_t
*q
, unsigned int mode
)
5689 __wake_up_common(q
, mode
, 1, 0, NULL
);
5692 void __wake_up_locked_key(wait_queue_head_t
*q
, unsigned int mode
, void *key
)
5694 __wake_up_common(q
, mode
, 1, 0, key
);
5698 * __wake_up_sync_key - wake up threads blocked on a waitqueue.
5700 * @mode: which threads
5701 * @nr_exclusive: how many wake-one or wake-many threads to wake up
5702 * @key: opaque value to be passed to wakeup targets
5704 * The sync wakeup differs that the waker knows that it will schedule
5705 * away soon, so while the target thread will be woken up, it will not
5706 * be migrated to another CPU - ie. the two threads are 'synchronized'
5707 * with each other. This can prevent needless bouncing between CPUs.
5709 * On UP it can prevent extra preemption.
5711 * It may be assumed that this function implies a write memory barrier before
5712 * changing the task state if and only if any tasks are woken up.
5714 void __wake_up_sync_key(wait_queue_head_t
*q
, unsigned int mode
,
5715 int nr_exclusive
, void *key
)
5717 unsigned long flags
;
5718 int wake_flags
= WF_SYNC
;
5723 if (unlikely(!nr_exclusive
))
5726 spin_lock_irqsave(&q
->lock
, flags
);
5727 __wake_up_common(q
, mode
, nr_exclusive
, wake_flags
, key
);
5728 spin_unlock_irqrestore(&q
->lock
, flags
);
5730 EXPORT_SYMBOL_GPL(__wake_up_sync_key
);
5733 * __wake_up_sync - see __wake_up_sync_key()
5735 void __wake_up_sync(wait_queue_head_t
*q
, unsigned int mode
, int nr_exclusive
)
5737 __wake_up_sync_key(q
, mode
, nr_exclusive
, NULL
);
5739 EXPORT_SYMBOL_GPL(__wake_up_sync
); /* For internal use only */
5742 * complete: - signals a single thread waiting on this completion
5743 * @x: holds the state of this particular completion
5745 * This will wake up a single thread waiting on this completion. Threads will be
5746 * awakened in the same order in which they were queued.
5748 * See also complete_all(), wait_for_completion() and related routines.
5750 * It may be assumed that this function implies a write memory barrier before
5751 * changing the task state if and only if any tasks are woken up.
5753 void complete(struct completion
*x
)
5755 unsigned long flags
;
5757 spin_lock_irqsave(&x
->wait
.lock
, flags
);
5759 __wake_up_common(&x
->wait
, TASK_NORMAL
, 1, 0, NULL
);
5760 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
5762 EXPORT_SYMBOL(complete
);
5765 * complete_all: - signals all threads waiting on this completion
5766 * @x: holds the state of this particular completion
5768 * This will wake up all threads waiting on this particular completion event.
5770 * It may be assumed that this function implies a write memory barrier before
5771 * changing the task state if and only if any tasks are woken up.
5773 void complete_all(struct completion
*x
)
5775 unsigned long flags
;
5777 spin_lock_irqsave(&x
->wait
.lock
, flags
);
5778 x
->done
+= UINT_MAX
/2;
5779 __wake_up_common(&x
->wait
, TASK_NORMAL
, 0, 0, NULL
);
5780 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
5782 EXPORT_SYMBOL(complete_all
);
5784 static inline long __sched
5785 do_wait_for_common(struct completion
*x
, long timeout
, int state
)
5788 DECLARE_WAITQUEUE(wait
, current
);
5790 wait
.flags
|= WQ_FLAG_EXCLUSIVE
;
5791 __add_wait_queue_tail(&x
->wait
, &wait
);
5793 if (signal_pending_state(state
, current
)) {
5794 timeout
= -ERESTARTSYS
;
5797 __set_current_state(state
);
5798 spin_unlock_irq(&x
->wait
.lock
);
5799 timeout
= schedule_timeout(timeout
);
5800 spin_lock_irq(&x
->wait
.lock
);
5801 } while (!x
->done
&& timeout
);
5802 __remove_wait_queue(&x
->wait
, &wait
);
5807 return timeout
?: 1;
5811 wait_for_common(struct completion
*x
, long timeout
, int state
)
5815 spin_lock_irq(&x
->wait
.lock
);
5816 timeout
= do_wait_for_common(x
, timeout
, state
);
5817 spin_unlock_irq(&x
->wait
.lock
);
5822 * wait_for_completion: - waits for completion of a task
5823 * @x: holds the state of this particular completion
5825 * This waits to be signaled for completion of a specific task. It is NOT
5826 * interruptible and there is no timeout.
5828 * See also similar routines (i.e. wait_for_completion_timeout()) with timeout
5829 * and interrupt capability. Also see complete().
5831 void __sched
wait_for_completion(struct completion
*x
)
5833 wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_UNINTERRUPTIBLE
);
5835 EXPORT_SYMBOL(wait_for_completion
);
5838 * wait_for_completion_timeout: - waits for completion of a task (w/timeout)
5839 * @x: holds the state of this particular completion
5840 * @timeout: timeout value in jiffies
5842 * This waits for either a completion of a specific task to be signaled or for a
5843 * specified timeout to expire. The timeout is in jiffies. It is not
5846 unsigned long __sched
5847 wait_for_completion_timeout(struct completion
*x
, unsigned long timeout
)
5849 return wait_for_common(x
, timeout
, TASK_UNINTERRUPTIBLE
);
5851 EXPORT_SYMBOL(wait_for_completion_timeout
);
5854 * wait_for_completion_interruptible: - waits for completion of a task (w/intr)
5855 * @x: holds the state of this particular completion
5857 * This waits for completion of a specific task to be signaled. It is
5860 int __sched
wait_for_completion_interruptible(struct completion
*x
)
5862 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_INTERRUPTIBLE
);
5863 if (t
== -ERESTARTSYS
)
5867 EXPORT_SYMBOL(wait_for_completion_interruptible
);
5870 * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr))
5871 * @x: holds the state of this particular completion
5872 * @timeout: timeout value in jiffies
5874 * This waits for either a completion of a specific task to be signaled or for a
5875 * specified timeout to expire. It is interruptible. The timeout is in jiffies.
5877 unsigned long __sched
5878 wait_for_completion_interruptible_timeout(struct completion
*x
,
5879 unsigned long timeout
)
5881 return wait_for_common(x
, timeout
, TASK_INTERRUPTIBLE
);
5883 EXPORT_SYMBOL(wait_for_completion_interruptible_timeout
);
5886 * wait_for_completion_killable: - waits for completion of a task (killable)
5887 * @x: holds the state of this particular completion
5889 * This waits to be signaled for completion of a specific task. It can be
5890 * interrupted by a kill signal.
5892 int __sched
wait_for_completion_killable(struct completion
*x
)
5894 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_KILLABLE
);
5895 if (t
== -ERESTARTSYS
)
5899 EXPORT_SYMBOL(wait_for_completion_killable
);
5902 * try_wait_for_completion - try to decrement a completion without blocking
5903 * @x: completion structure
5905 * Returns: 0 if a decrement cannot be done without blocking
5906 * 1 if a decrement succeeded.
5908 * If a completion is being used as a counting completion,
5909 * attempt to decrement the counter without blocking. This
5910 * enables us to avoid waiting if the resource the completion
5911 * is protecting is not available.
5913 bool try_wait_for_completion(struct completion
*x
)
5915 unsigned long flags
;
5918 spin_lock_irqsave(&x
->wait
.lock
, flags
);
5923 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
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
)
5938 unsigned long flags
;
5941 spin_lock_irqsave(&x
->wait
.lock
, flags
);
5944 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
5947 EXPORT_SYMBOL(completion_done
);
5950 sleep_on_common(wait_queue_head_t
*q
, int state
, long timeout
)
5952 unsigned long flags
;
5955 init_waitqueue_entry(&wait
, current
);
5957 __set_current_state(state
);
5959 spin_lock_irqsave(&q
->lock
, flags
);
5960 __add_wait_queue(q
, &wait
);
5961 spin_unlock(&q
->lock
);
5962 timeout
= schedule_timeout(timeout
);
5963 spin_lock_irq(&q
->lock
);
5964 __remove_wait_queue(q
, &wait
);
5965 spin_unlock_irqrestore(&q
->lock
, flags
);
5970 void __sched
interruptible_sleep_on(wait_queue_head_t
*q
)
5972 sleep_on_common(q
, TASK_INTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
5974 EXPORT_SYMBOL(interruptible_sleep_on
);
5977 interruptible_sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
5979 return sleep_on_common(q
, TASK_INTERRUPTIBLE
, timeout
);
5981 EXPORT_SYMBOL(interruptible_sleep_on_timeout
);
5983 void __sched
sleep_on(wait_queue_head_t
*q
)
5985 sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
5987 EXPORT_SYMBOL(sleep_on
);
5989 long __sched
sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
5991 return sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, timeout
);
5993 EXPORT_SYMBOL(sleep_on_timeout
);
5995 #ifdef CONFIG_RT_MUTEXES
5998 * rt_mutex_setprio - set the current priority of a task
6000 * @prio: prio value (kernel-internal form)
6002 * This function changes the 'effective' priority of a task. It does
6003 * not touch ->normal_prio like __setscheduler().
6005 * Used by the rt_mutex code to implement priority inheritance logic.
6007 void rt_mutex_setprio(struct task_struct
*p
, int prio
)
6009 unsigned long flags
;
6010 int oldprio
, on_rq
, running
;
6012 const struct sched_class
*prev_class
= p
->sched_class
;
6014 BUG_ON(prio
< 0 || prio
> MAX_PRIO
);
6016 rq
= task_rq_lock(p
, &flags
);
6017 update_rq_clock(rq
);
6020 on_rq
= p
->se
.on_rq
;
6021 running
= task_current(rq
, p
);
6023 dequeue_task(rq
, p
, 0);
6025 p
->sched_class
->put_prev_task(rq
, p
);
6028 p
->sched_class
= &rt_sched_class
;
6030 p
->sched_class
= &fair_sched_class
;
6035 p
->sched_class
->set_curr_task(rq
);
6037 enqueue_task(rq
, p
, 0);
6039 check_class_changed(rq
, p
, prev_class
, oldprio
, running
);
6041 task_rq_unlock(rq
, &flags
);
6046 void set_user_nice(struct task_struct
*p
, long nice
)
6048 int old_prio
, delta
, on_rq
;
6049 unsigned long flags
;
6052 if (TASK_NICE(p
) == nice
|| nice
< -20 || nice
> 19)
6055 * We have to be careful, if called from sys_setpriority(),
6056 * the task might be in the middle of scheduling on another CPU.
6058 rq
= task_rq_lock(p
, &flags
);
6059 update_rq_clock(rq
);
6061 * The RT priorities are set via sched_setscheduler(), but we still
6062 * allow the 'normal' nice value to be set - but as expected
6063 * it wont have any effect on scheduling until the task is
6064 * SCHED_FIFO/SCHED_RR:
6066 if (task_has_rt_policy(p
)) {
6067 p
->static_prio
= NICE_TO_PRIO(nice
);
6070 on_rq
= p
->se
.on_rq
;
6072 dequeue_task(rq
, p
, 0);
6074 p
->static_prio
= NICE_TO_PRIO(nice
);
6077 p
->prio
= effective_prio(p
);
6078 delta
= p
->prio
- old_prio
;
6081 enqueue_task(rq
, p
, 0);
6083 * If the task increased its priority or is running and
6084 * lowered its priority, then reschedule its CPU:
6086 if (delta
< 0 || (delta
> 0 && task_running(rq
, p
)))
6087 resched_task(rq
->curr
);
6090 task_rq_unlock(rq
, &flags
);
6092 EXPORT_SYMBOL(set_user_nice
);
6095 * can_nice - check if a task can reduce its nice value
6099 int can_nice(const struct task_struct
*p
, const int nice
)
6101 /* convert nice value [19,-20] to rlimit style value [1,40] */
6102 int nice_rlim
= 20 - nice
;
6104 return (nice_rlim
<= p
->signal
->rlim
[RLIMIT_NICE
].rlim_cur
||
6105 capable(CAP_SYS_NICE
));
6108 #ifdef __ARCH_WANT_SYS_NICE
6111 * sys_nice - change the priority of the current process.
6112 * @increment: priority increment
6114 * sys_setpriority is a more generic, but much slower function that
6115 * does similar things.
6117 SYSCALL_DEFINE1(nice
, int, increment
)
6122 * Setpriority might change our priority at the same moment.
6123 * We don't have to worry. Conceptually one call occurs first
6124 * and we have a single winner.
6126 if (increment
< -40)
6131 nice
= TASK_NICE(current
) + increment
;
6137 if (increment
< 0 && !can_nice(current
, nice
))
6140 retval
= security_task_setnice(current
, nice
);
6144 set_user_nice(current
, nice
);
6151 * task_prio - return the priority value of a given task.
6152 * @p: the task in question.
6154 * This is the priority value as seen by users in /proc.
6155 * RT tasks are offset by -200. Normal tasks are centered
6156 * around 0, value goes from -16 to +15.
6158 int task_prio(const struct task_struct
*p
)
6160 return p
->prio
- MAX_RT_PRIO
;
6164 * task_nice - return the nice value of a given task.
6165 * @p: the task in question.
6167 int task_nice(const struct task_struct
*p
)
6169 return TASK_NICE(p
);
6171 EXPORT_SYMBOL(task_nice
);
6174 * idle_cpu - is a given cpu idle currently?
6175 * @cpu: the processor in question.
6177 int idle_cpu(int cpu
)
6179 return cpu_curr(cpu
) == cpu_rq(cpu
)->idle
;
6183 * idle_task - return the idle task for a given cpu.
6184 * @cpu: the processor in question.
6186 struct task_struct
*idle_task(int cpu
)
6188 return cpu_rq(cpu
)->idle
;
6192 * find_process_by_pid - find a process with a matching PID value.
6193 * @pid: the pid in question.
6195 static struct task_struct
*find_process_by_pid(pid_t pid
)
6197 return pid
? find_task_by_vpid(pid
) : current
;
6200 /* Actually do priority change: must hold rq lock. */
6202 __setscheduler(struct rq
*rq
, struct task_struct
*p
, int policy
, int prio
)
6204 BUG_ON(p
->se
.on_rq
);
6207 p
->rt_priority
= prio
;
6208 p
->normal_prio
= normal_prio(p
);
6209 /* we are holding p->pi_lock already */
6210 p
->prio
= rt_mutex_getprio(p
);
6211 if (rt_prio(p
->prio
))
6212 p
->sched_class
= &rt_sched_class
;
6214 p
->sched_class
= &fair_sched_class
;
6219 * check the target process has a UID that matches the current process's
6221 static bool check_same_owner(struct task_struct
*p
)
6223 const struct cred
*cred
= current_cred(), *pcred
;
6227 pcred
= __task_cred(p
);
6228 match
= (cred
->euid
== pcred
->euid
||
6229 cred
->euid
== pcred
->uid
);
6234 static int __sched_setscheduler(struct task_struct
*p
, int policy
,
6235 struct sched_param
*param
, bool user
)
6237 int retval
, oldprio
, oldpolicy
= -1, on_rq
, running
;
6238 unsigned long flags
;
6239 const struct sched_class
*prev_class
= p
->sched_class
;
6243 /* may grab non-irq protected spin_locks */
6244 BUG_ON(in_interrupt());
6246 /* double check policy once rq lock held */
6248 reset_on_fork
= p
->sched_reset_on_fork
;
6249 policy
= oldpolicy
= p
->policy
;
6251 reset_on_fork
= !!(policy
& SCHED_RESET_ON_FORK
);
6252 policy
&= ~SCHED_RESET_ON_FORK
;
6254 if (policy
!= SCHED_FIFO
&& policy
!= SCHED_RR
&&
6255 policy
!= SCHED_NORMAL
&& policy
!= SCHED_BATCH
&&
6256 policy
!= SCHED_IDLE
)
6261 * Valid priorities for SCHED_FIFO and SCHED_RR are
6262 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
6263 * SCHED_BATCH and SCHED_IDLE is 0.
6265 if (param
->sched_priority
< 0 ||
6266 (p
->mm
&& param
->sched_priority
> MAX_USER_RT_PRIO
-1) ||
6267 (!p
->mm
&& param
->sched_priority
> MAX_RT_PRIO
-1))
6269 if (rt_policy(policy
) != (param
->sched_priority
!= 0))
6273 * Allow unprivileged RT tasks to decrease priority:
6275 if (user
&& !capable(CAP_SYS_NICE
)) {
6276 if (rt_policy(policy
)) {
6277 unsigned long rlim_rtprio
;
6279 if (!lock_task_sighand(p
, &flags
))
6281 rlim_rtprio
= p
->signal
->rlim
[RLIMIT_RTPRIO
].rlim_cur
;
6282 unlock_task_sighand(p
, &flags
);
6284 /* can't set/change the rt policy */
6285 if (policy
!= p
->policy
&& !rlim_rtprio
)
6288 /* can't increase priority */
6289 if (param
->sched_priority
> p
->rt_priority
&&
6290 param
->sched_priority
> rlim_rtprio
)
6294 * Like positive nice levels, dont allow tasks to
6295 * move out of SCHED_IDLE either:
6297 if (p
->policy
== SCHED_IDLE
&& policy
!= SCHED_IDLE
)
6300 /* can't change other user's priorities */
6301 if (!check_same_owner(p
))
6304 /* Normal users shall not reset the sched_reset_on_fork flag */
6305 if (p
->sched_reset_on_fork
&& !reset_on_fork
)
6310 #ifdef CONFIG_RT_GROUP_SCHED
6312 * Do not allow realtime tasks into groups that have no runtime
6315 if (rt_bandwidth_enabled() && rt_policy(policy
) &&
6316 task_group(p
)->rt_bandwidth
.rt_runtime
== 0)
6320 retval
= security_task_setscheduler(p
, policy
, param
);
6326 * make sure no PI-waiters arrive (or leave) while we are
6327 * changing the priority of the task:
6329 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
6331 * To be able to change p->policy safely, the apropriate
6332 * runqueue lock must be held.
6334 rq
= __task_rq_lock(p
);
6335 /* recheck policy now with rq lock held */
6336 if (unlikely(oldpolicy
!= -1 && oldpolicy
!= p
->policy
)) {
6337 policy
= oldpolicy
= -1;
6338 __task_rq_unlock(rq
);
6339 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
6342 update_rq_clock(rq
);
6343 on_rq
= p
->se
.on_rq
;
6344 running
= task_current(rq
, p
);
6346 deactivate_task(rq
, p
, 0);
6348 p
->sched_class
->put_prev_task(rq
, p
);
6350 p
->sched_reset_on_fork
= reset_on_fork
;
6353 __setscheduler(rq
, p
, policy
, param
->sched_priority
);
6356 p
->sched_class
->set_curr_task(rq
);
6358 activate_task(rq
, p
, 0);
6360 check_class_changed(rq
, p
, prev_class
, oldprio
, running
);
6362 __task_rq_unlock(rq
);
6363 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
6365 rt_mutex_adjust_pi(p
);
6371 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
6372 * @p: the task in question.
6373 * @policy: new policy.
6374 * @param: structure containing the new RT priority.
6376 * NOTE that the task may be already dead.
6378 int sched_setscheduler(struct task_struct
*p
, int policy
,
6379 struct sched_param
*param
)
6381 return __sched_setscheduler(p
, policy
, param
, true);
6383 EXPORT_SYMBOL_GPL(sched_setscheduler
);
6386 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
6387 * @p: the task in question.
6388 * @policy: new policy.
6389 * @param: structure containing the new RT priority.
6391 * Just like sched_setscheduler, only don't bother checking if the
6392 * current context has permission. For example, this is needed in
6393 * stop_machine(): we create temporary high priority worker threads,
6394 * but our caller might not have that capability.
6396 int sched_setscheduler_nocheck(struct task_struct
*p
, int policy
,
6397 struct sched_param
*param
)
6399 return __sched_setscheduler(p
, policy
, param
, false);
6403 do_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
6405 struct sched_param lparam
;
6406 struct task_struct
*p
;
6409 if (!param
|| pid
< 0)
6411 if (copy_from_user(&lparam
, param
, sizeof(struct sched_param
)))
6416 p
= find_process_by_pid(pid
);
6418 retval
= sched_setscheduler(p
, policy
, &lparam
);
6425 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
6426 * @pid: the pid in question.
6427 * @policy: new policy.
6428 * @param: structure containing the new RT priority.
6430 SYSCALL_DEFINE3(sched_setscheduler
, pid_t
, pid
, int, policy
,
6431 struct sched_param __user
*, param
)
6433 /* negative values for policy are not valid */
6437 return do_sched_setscheduler(pid
, policy
, param
);
6441 * sys_sched_setparam - set/change the RT priority of a thread
6442 * @pid: the pid in question.
6443 * @param: structure containing the new RT priority.
6445 SYSCALL_DEFINE2(sched_setparam
, pid_t
, pid
, struct sched_param __user
*, param
)
6447 return do_sched_setscheduler(pid
, -1, param
);
6451 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
6452 * @pid: the pid in question.
6454 SYSCALL_DEFINE1(sched_getscheduler
, pid_t
, pid
)
6456 struct task_struct
*p
;
6464 p
= find_process_by_pid(pid
);
6466 retval
= security_task_getscheduler(p
);
6469 | (p
->sched_reset_on_fork
? SCHED_RESET_ON_FORK
: 0);
6476 * sys_sched_getparam - get the RT priority of a thread
6477 * @pid: the pid in question.
6478 * @param: structure containing the RT priority.
6480 SYSCALL_DEFINE2(sched_getparam
, pid_t
, pid
, struct sched_param __user
*, param
)
6482 struct sched_param lp
;
6483 struct task_struct
*p
;
6486 if (!param
|| pid
< 0)
6490 p
= find_process_by_pid(pid
);
6495 retval
= security_task_getscheduler(p
);
6499 lp
.sched_priority
= p
->rt_priority
;
6503 * This one might sleep, we cannot do it with a spinlock held ...
6505 retval
= copy_to_user(param
, &lp
, sizeof(*param
)) ? -EFAULT
: 0;
6514 long sched_setaffinity(pid_t pid
, const struct cpumask
*in_mask
)
6516 cpumask_var_t cpus_allowed
, new_mask
;
6517 struct task_struct
*p
;
6523 p
= find_process_by_pid(pid
);
6530 /* Prevent p going away */
6534 if (!alloc_cpumask_var(&cpus_allowed
, GFP_KERNEL
)) {
6538 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
)) {
6540 goto out_free_cpus_allowed
;
6543 if (!check_same_owner(p
) && !capable(CAP_SYS_NICE
))
6546 retval
= security_task_setscheduler(p
, 0, NULL
);
6550 cpuset_cpus_allowed(p
, cpus_allowed
);
6551 cpumask_and(new_mask
, in_mask
, cpus_allowed
);
6553 retval
= set_cpus_allowed_ptr(p
, new_mask
);
6556 cpuset_cpus_allowed(p
, cpus_allowed
);
6557 if (!cpumask_subset(new_mask
, cpus_allowed
)) {
6559 * We must have raced with a concurrent cpuset
6560 * update. Just reset the cpus_allowed to the
6561 * cpuset's cpus_allowed
6563 cpumask_copy(new_mask
, cpus_allowed
);
6568 free_cpumask_var(new_mask
);
6569 out_free_cpus_allowed
:
6570 free_cpumask_var(cpus_allowed
);
6577 static int get_user_cpu_mask(unsigned long __user
*user_mask_ptr
, unsigned len
,
6578 struct cpumask
*new_mask
)
6580 if (len
< cpumask_size())
6581 cpumask_clear(new_mask
);
6582 else if (len
> cpumask_size())
6583 len
= cpumask_size();
6585 return copy_from_user(new_mask
, user_mask_ptr
, len
) ? -EFAULT
: 0;
6589 * sys_sched_setaffinity - set the cpu affinity of a process
6590 * @pid: pid of the process
6591 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
6592 * @user_mask_ptr: user-space pointer to the new cpu mask
6594 SYSCALL_DEFINE3(sched_setaffinity
, pid_t
, pid
, unsigned int, len
,
6595 unsigned long __user
*, user_mask_ptr
)
6597 cpumask_var_t new_mask
;
6600 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
))
6603 retval
= get_user_cpu_mask(user_mask_ptr
, len
, new_mask
);
6605 retval
= sched_setaffinity(pid
, new_mask
);
6606 free_cpumask_var(new_mask
);
6610 long sched_getaffinity(pid_t pid
, struct cpumask
*mask
)
6612 struct task_struct
*p
;
6613 unsigned long flags
;
6621 p
= find_process_by_pid(pid
);
6625 retval
= security_task_getscheduler(p
);
6629 rq
= task_rq_lock(p
, &flags
);
6630 cpumask_and(mask
, &p
->cpus_allowed
, cpu_online_mask
);
6631 task_rq_unlock(rq
, &flags
);
6641 * sys_sched_getaffinity - get the cpu affinity of a process
6642 * @pid: pid of the process
6643 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
6644 * @user_mask_ptr: user-space pointer to hold the current cpu mask
6646 SYSCALL_DEFINE3(sched_getaffinity
, pid_t
, pid
, unsigned int, len
,
6647 unsigned long __user
*, user_mask_ptr
)
6652 if (len
< cpumask_size())
6655 if (!alloc_cpumask_var(&mask
, GFP_KERNEL
))
6658 ret
= sched_getaffinity(pid
, mask
);
6660 if (copy_to_user(user_mask_ptr
, mask
, cpumask_size()))
6663 ret
= cpumask_size();
6665 free_cpumask_var(mask
);
6671 * sys_sched_yield - yield the current processor to other threads.
6673 * This function yields the current CPU to other tasks. If there are no
6674 * other threads running on this CPU then this function will return.
6676 SYSCALL_DEFINE0(sched_yield
)
6678 struct rq
*rq
= this_rq_lock();
6680 schedstat_inc(rq
, yld_count
);
6681 current
->sched_class
->yield_task(rq
);
6684 * Since we are going to call schedule() anyway, there's
6685 * no need to preempt or enable interrupts:
6687 __release(rq
->lock
);
6688 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
6689 do_raw_spin_unlock(&rq
->lock
);
6690 preempt_enable_no_resched();
6697 static inline int should_resched(void)
6699 return need_resched() && !(preempt_count() & PREEMPT_ACTIVE
);
6702 static void __cond_resched(void)
6704 add_preempt_count(PREEMPT_ACTIVE
);
6706 sub_preempt_count(PREEMPT_ACTIVE
);
6709 int __sched
_cond_resched(void)
6711 if (should_resched()) {
6717 EXPORT_SYMBOL(_cond_resched
);
6720 * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
6721 * call schedule, and on return reacquire the lock.
6723 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
6724 * operations here to prevent schedule() from being called twice (once via
6725 * spin_unlock(), once by hand).
6727 int __cond_resched_lock(spinlock_t
*lock
)
6729 int resched
= should_resched();
6732 lockdep_assert_held(lock
);
6734 if (spin_needbreak(lock
) || resched
) {
6745 EXPORT_SYMBOL(__cond_resched_lock
);
6747 int __sched
__cond_resched_softirq(void)
6749 BUG_ON(!in_softirq());
6751 if (should_resched()) {
6759 EXPORT_SYMBOL(__cond_resched_softirq
);
6762 * yield - yield the current processor to other threads.
6764 * This is a shortcut for kernel-space yielding - it marks the
6765 * thread runnable and calls sys_sched_yield().
6767 void __sched
yield(void)
6769 set_current_state(TASK_RUNNING
);
6772 EXPORT_SYMBOL(yield
);
6775 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
6776 * that process accounting knows that this is a task in IO wait state.
6778 void __sched
io_schedule(void)
6780 struct rq
*rq
= raw_rq();
6782 delayacct_blkio_start();
6783 atomic_inc(&rq
->nr_iowait
);
6784 current
->in_iowait
= 1;
6786 current
->in_iowait
= 0;
6787 atomic_dec(&rq
->nr_iowait
);
6788 delayacct_blkio_end();
6790 EXPORT_SYMBOL(io_schedule
);
6792 long __sched
io_schedule_timeout(long timeout
)
6794 struct rq
*rq
= raw_rq();
6797 delayacct_blkio_start();
6798 atomic_inc(&rq
->nr_iowait
);
6799 current
->in_iowait
= 1;
6800 ret
= schedule_timeout(timeout
);
6801 current
->in_iowait
= 0;
6802 atomic_dec(&rq
->nr_iowait
);
6803 delayacct_blkio_end();
6808 * sys_sched_get_priority_max - return maximum RT priority.
6809 * @policy: scheduling class.
6811 * this syscall returns the maximum rt_priority that can be used
6812 * by a given scheduling class.
6814 SYSCALL_DEFINE1(sched_get_priority_max
, int, policy
)
6821 ret
= MAX_USER_RT_PRIO
-1;
6833 * sys_sched_get_priority_min - return minimum RT priority.
6834 * @policy: scheduling class.
6836 * this syscall returns the minimum rt_priority that can be used
6837 * by a given scheduling class.
6839 SYSCALL_DEFINE1(sched_get_priority_min
, int, policy
)
6857 * sys_sched_rr_get_interval - return the default timeslice of a process.
6858 * @pid: pid of the process.
6859 * @interval: userspace pointer to the timeslice value.
6861 * this syscall writes the default timeslice value of a given process
6862 * into the user-space timespec buffer. A value of '0' means infinity.
6864 SYSCALL_DEFINE2(sched_rr_get_interval
, pid_t
, pid
,
6865 struct timespec __user
*, interval
)
6867 struct task_struct
*p
;
6868 unsigned int time_slice
;
6869 unsigned long flags
;
6879 p
= find_process_by_pid(pid
);
6883 retval
= security_task_getscheduler(p
);
6887 rq
= task_rq_lock(p
, &flags
);
6888 time_slice
= p
->sched_class
->get_rr_interval(rq
, p
);
6889 task_rq_unlock(rq
, &flags
);
6892 jiffies_to_timespec(time_slice
, &t
);
6893 retval
= copy_to_user(interval
, &t
, sizeof(t
)) ? -EFAULT
: 0;
6901 static const char stat_nam
[] = TASK_STATE_TO_CHAR_STR
;
6903 void sched_show_task(struct task_struct
*p
)
6905 unsigned long free
= 0;
6908 state
= p
->state
? __ffs(p
->state
) + 1 : 0;
6909 pr_info("%-13.13s %c", p
->comm
,
6910 state
< sizeof(stat_nam
) - 1 ? stat_nam
[state
] : '?');
6911 #if BITS_PER_LONG == 32
6912 if (state
== TASK_RUNNING
)
6913 pr_cont(" running ");
6915 pr_cont(" %08lx ", thread_saved_pc(p
));
6917 if (state
== TASK_RUNNING
)
6918 pr_cont(" running task ");
6920 pr_cont(" %016lx ", thread_saved_pc(p
));
6922 #ifdef CONFIG_DEBUG_STACK_USAGE
6923 free
= stack_not_used(p
);
6925 pr_cont("%5lu %5d %6d 0x%08lx\n", free
,
6926 task_pid_nr(p
), task_pid_nr(p
->real_parent
),
6927 (unsigned long)task_thread_info(p
)->flags
);
6929 show_stack(p
, NULL
);
6932 void show_state_filter(unsigned long state_filter
)
6934 struct task_struct
*g
, *p
;
6936 #if BITS_PER_LONG == 32
6937 pr_info(" task PC stack pid father\n");
6939 pr_info(" task PC stack pid father\n");
6941 read_lock(&tasklist_lock
);
6942 do_each_thread(g
, p
) {
6944 * reset the NMI-timeout, listing all files on a slow
6945 * console might take alot of time:
6947 touch_nmi_watchdog();
6948 if (!state_filter
|| (p
->state
& state_filter
))
6950 } while_each_thread(g
, p
);
6952 touch_all_softlockup_watchdogs();
6954 #ifdef CONFIG_SCHED_DEBUG
6955 sysrq_sched_debug_show();
6957 read_unlock(&tasklist_lock
);
6959 * Only show locks if all tasks are dumped:
6962 debug_show_all_locks();
6965 void __cpuinit
init_idle_bootup_task(struct task_struct
*idle
)
6967 idle
->sched_class
= &idle_sched_class
;
6971 * init_idle - set up an idle thread for a given CPU
6972 * @idle: task in question
6973 * @cpu: cpu the idle task belongs to
6975 * NOTE: this function does not set the idle thread's NEED_RESCHED
6976 * flag, to make booting more robust.
6978 void __cpuinit
init_idle(struct task_struct
*idle
, int cpu
)
6980 struct rq
*rq
= cpu_rq(cpu
);
6981 unsigned long flags
;
6983 raw_spin_lock_irqsave(&rq
->lock
, flags
);
6986 idle
->state
= TASK_RUNNING
;
6987 idle
->se
.exec_start
= sched_clock();
6989 cpumask_copy(&idle
->cpus_allowed
, cpumask_of(cpu
));
6990 __set_task_cpu(idle
, cpu
);
6992 rq
->curr
= rq
->idle
= idle
;
6993 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
6996 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
6998 /* Set the preempt count _outside_ the spinlocks! */
6999 #if defined(CONFIG_PREEMPT)
7000 task_thread_info(idle
)->preempt_count
= (idle
->lock_depth
>= 0);
7002 task_thread_info(idle
)->preempt_count
= 0;
7005 * The idle tasks have their own, simple scheduling class:
7007 idle
->sched_class
= &idle_sched_class
;
7008 ftrace_graph_init_task(idle
);
7012 * In a system that switches off the HZ timer nohz_cpu_mask
7013 * indicates which cpus entered this state. This is used
7014 * in the rcu update to wait only for active cpus. For system
7015 * which do not switch off the HZ timer nohz_cpu_mask should
7016 * always be CPU_BITS_NONE.
7018 cpumask_var_t nohz_cpu_mask
;
7021 * Increase the granularity value when there are more CPUs,
7022 * because with more CPUs the 'effective latency' as visible
7023 * to users decreases. But the relationship is not linear,
7024 * so pick a second-best guess by going with the log2 of the
7027 * This idea comes from the SD scheduler of Con Kolivas:
7029 static int get_update_sysctl_factor(void)
7031 unsigned int cpus
= min_t(int, num_online_cpus(), 8);
7032 unsigned int factor
;
7034 switch (sysctl_sched_tunable_scaling
) {
7035 case SCHED_TUNABLESCALING_NONE
:
7038 case SCHED_TUNABLESCALING_LINEAR
:
7041 case SCHED_TUNABLESCALING_LOG
:
7043 factor
= 1 + ilog2(cpus
);
7050 static void update_sysctl(void)
7052 unsigned int factor
= get_update_sysctl_factor();
7054 #define SET_SYSCTL(name) \
7055 (sysctl_##name = (factor) * normalized_sysctl_##name)
7056 SET_SYSCTL(sched_min_granularity
);
7057 SET_SYSCTL(sched_latency
);
7058 SET_SYSCTL(sched_wakeup_granularity
);
7059 SET_SYSCTL(sched_shares_ratelimit
);
7063 static inline void sched_init_granularity(void)
7070 * This is how migration works:
7072 * 1) we queue a struct migration_req structure in the source CPU's
7073 * runqueue and wake up that CPU's migration thread.
7074 * 2) we down() the locked semaphore => thread blocks.
7075 * 3) migration thread wakes up (implicitly it forces the migrated
7076 * thread off the CPU)
7077 * 4) it gets the migration request and checks whether the migrated
7078 * task is still in the wrong runqueue.
7079 * 5) if it's in the wrong runqueue then the migration thread removes
7080 * it and puts it into the right queue.
7081 * 6) migration thread up()s the semaphore.
7082 * 7) we wake up and the migration is done.
7086 * Change a given task's CPU affinity. Migrate the thread to a
7087 * proper CPU and schedule it away if the CPU it's executing on
7088 * is removed from the allowed bitmask.
7090 * NOTE: the caller must have a valid reference to the task, the
7091 * task must not exit() & deallocate itself prematurely. The
7092 * call is not atomic; no spinlocks may be held.
7094 int set_cpus_allowed_ptr(struct task_struct
*p
, const struct cpumask
*new_mask
)
7096 struct migration_req req
;
7097 unsigned long flags
;
7101 rq
= task_rq_lock(p
, &flags
);
7102 if (!cpumask_intersects(new_mask
, cpu_active_mask
)) {
7107 if (unlikely((p
->flags
& PF_THREAD_BOUND
) && p
!= current
&&
7108 !cpumask_equal(&p
->cpus_allowed
, new_mask
))) {
7113 if (p
->sched_class
->set_cpus_allowed
)
7114 p
->sched_class
->set_cpus_allowed(p
, new_mask
);
7116 cpumask_copy(&p
->cpus_allowed
, new_mask
);
7117 p
->rt
.nr_cpus_allowed
= cpumask_weight(new_mask
);
7120 /* Can the task run on the task's current CPU? If so, we're done */
7121 if (cpumask_test_cpu(task_cpu(p
), new_mask
))
7124 if (migrate_task(p
, cpumask_any_and(cpu_active_mask
, new_mask
), &req
)) {
7125 /* Need help from migration thread: drop lock and wait. */
7126 struct task_struct
*mt
= rq
->migration_thread
;
7128 get_task_struct(mt
);
7129 task_rq_unlock(rq
, &flags
);
7130 wake_up_process(rq
->migration_thread
);
7131 put_task_struct(mt
);
7132 wait_for_completion(&req
.done
);
7133 tlb_migrate_finish(p
->mm
);
7137 task_rq_unlock(rq
, &flags
);
7141 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr
);
7144 * Move (not current) task off this cpu, onto dest cpu. We're doing
7145 * this because either it can't run here any more (set_cpus_allowed()
7146 * away from this CPU, or CPU going down), or because we're
7147 * attempting to rebalance this task on exec (sched_exec).
7149 * So we race with normal scheduler movements, but that's OK, as long
7150 * as the task is no longer on this CPU.
7152 * Returns non-zero if task was successfully migrated.
7154 static int __migrate_task(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
7156 struct rq
*rq_dest
, *rq_src
;
7159 if (unlikely(!cpu_active(dest_cpu
)))
7162 rq_src
= cpu_rq(src_cpu
);
7163 rq_dest
= cpu_rq(dest_cpu
);
7165 double_rq_lock(rq_src
, rq_dest
);
7166 /* Already moved. */
7167 if (task_cpu(p
) != src_cpu
)
7169 /* Affinity changed (again). */
7170 if (!cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
))
7173 on_rq
= p
->se
.on_rq
;
7175 deactivate_task(rq_src
, p
, 0);
7177 set_task_cpu(p
, dest_cpu
);
7179 activate_task(rq_dest
, p
, 0);
7180 check_preempt_curr(rq_dest
, p
, 0);
7185 double_rq_unlock(rq_src
, rq_dest
);
7189 #define RCU_MIGRATION_IDLE 0
7190 #define RCU_MIGRATION_NEED_QS 1
7191 #define RCU_MIGRATION_GOT_QS 2
7192 #define RCU_MIGRATION_MUST_SYNC 3
7195 * migration_thread - this is a highprio system thread that performs
7196 * thread migration by bumping thread off CPU then 'pushing' onto
7199 static int migration_thread(void *data
)
7202 int cpu
= (long)data
;
7206 BUG_ON(rq
->migration_thread
!= current
);
7208 set_current_state(TASK_INTERRUPTIBLE
);
7209 while (!kthread_should_stop()) {
7210 struct migration_req
*req
;
7211 struct list_head
*head
;
7213 raw_spin_lock_irq(&rq
->lock
);
7215 if (cpu_is_offline(cpu
)) {
7216 raw_spin_unlock_irq(&rq
->lock
);
7220 if (rq
->active_balance
) {
7221 active_load_balance(rq
, cpu
);
7222 rq
->active_balance
= 0;
7225 head
= &rq
->migration_queue
;
7227 if (list_empty(head
)) {
7228 raw_spin_unlock_irq(&rq
->lock
);
7230 set_current_state(TASK_INTERRUPTIBLE
);
7233 req
= list_entry(head
->next
, struct migration_req
, list
);
7234 list_del_init(head
->next
);
7236 if (req
->task
!= NULL
) {
7237 raw_spin_unlock(&rq
->lock
);
7238 __migrate_task(req
->task
, cpu
, req
->dest_cpu
);
7239 } else if (likely(cpu
== (badcpu
= smp_processor_id()))) {
7240 req
->dest_cpu
= RCU_MIGRATION_GOT_QS
;
7241 raw_spin_unlock(&rq
->lock
);
7243 req
->dest_cpu
= RCU_MIGRATION_MUST_SYNC
;
7244 raw_spin_unlock(&rq
->lock
);
7245 WARN_ONCE(1, "migration_thread() on CPU %d, expected %d\n", badcpu
, cpu
);
7249 complete(&req
->done
);
7251 __set_current_state(TASK_RUNNING
);
7256 #ifdef CONFIG_HOTPLUG_CPU
7258 static int __migrate_task_irq(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
7262 local_irq_disable();
7263 ret
= __migrate_task(p
, src_cpu
, dest_cpu
);
7269 * Figure out where task on dead CPU should go, use force if necessary.
7271 static void move_task_off_dead_cpu(int dead_cpu
, struct task_struct
*p
)
7274 const struct cpumask
*nodemask
= cpumask_of_node(cpu_to_node(dead_cpu
));
7277 /* Look for allowed, online CPU in same node. */
7278 for_each_cpu_and(dest_cpu
, nodemask
, cpu_active_mask
)
7279 if (cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
))
7282 /* Any allowed, online CPU? */
7283 dest_cpu
= cpumask_any_and(&p
->cpus_allowed
, cpu_active_mask
);
7284 if (dest_cpu
< nr_cpu_ids
)
7287 /* No more Mr. Nice Guy. */
7288 if (dest_cpu
>= nr_cpu_ids
) {
7289 cpuset_cpus_allowed_locked(p
, &p
->cpus_allowed
);
7290 dest_cpu
= cpumask_any_and(cpu_active_mask
, &p
->cpus_allowed
);
7293 * Don't tell them about moving exiting tasks or
7294 * kernel threads (both mm NULL), since they never
7297 if (p
->mm
&& printk_ratelimit()) {
7298 pr_info("process %d (%s) no longer affine to cpu%d\n",
7299 task_pid_nr(p
), p
->comm
, dead_cpu
);
7304 /* It can have affinity changed while we were choosing. */
7305 if (unlikely(!__migrate_task_irq(p
, dead_cpu
, dest_cpu
)))
7310 * While a dead CPU has no uninterruptible tasks queued at this point,
7311 * it might still have a nonzero ->nr_uninterruptible counter, because
7312 * for performance reasons the counter is not stricly tracking tasks to
7313 * their home CPUs. So we just add the counter to another CPU's counter,
7314 * to keep the global sum constant after CPU-down:
7316 static void migrate_nr_uninterruptible(struct rq
*rq_src
)
7318 struct rq
*rq_dest
= cpu_rq(cpumask_any(cpu_active_mask
));
7319 unsigned long flags
;
7321 local_irq_save(flags
);
7322 double_rq_lock(rq_src
, rq_dest
);
7323 rq_dest
->nr_uninterruptible
+= rq_src
->nr_uninterruptible
;
7324 rq_src
->nr_uninterruptible
= 0;
7325 double_rq_unlock(rq_src
, rq_dest
);
7326 local_irq_restore(flags
);
7329 /* Run through task list and migrate tasks from the dead cpu. */
7330 static void migrate_live_tasks(int src_cpu
)
7332 struct task_struct
*p
, *t
;
7334 read_lock(&tasklist_lock
);
7336 do_each_thread(t
, p
) {
7340 if (task_cpu(p
) == src_cpu
)
7341 move_task_off_dead_cpu(src_cpu
, p
);
7342 } while_each_thread(t
, p
);
7344 read_unlock(&tasklist_lock
);
7348 * Schedules idle task to be the next runnable task on current CPU.
7349 * It does so by boosting its priority to highest possible.
7350 * Used by CPU offline code.
7352 void sched_idle_next(void)
7354 int this_cpu
= smp_processor_id();
7355 struct rq
*rq
= cpu_rq(this_cpu
);
7356 struct task_struct
*p
= rq
->idle
;
7357 unsigned long flags
;
7359 /* cpu has to be offline */
7360 BUG_ON(cpu_online(this_cpu
));
7363 * Strictly not necessary since rest of the CPUs are stopped by now
7364 * and interrupts disabled on the current cpu.
7366 raw_spin_lock_irqsave(&rq
->lock
, flags
);
7368 __setscheduler(rq
, p
, SCHED_FIFO
, MAX_RT_PRIO
-1);
7370 update_rq_clock(rq
);
7371 activate_task(rq
, p
, 0);
7373 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
7377 * Ensures that the idle task is using init_mm right before its cpu goes
7380 void idle_task_exit(void)
7382 struct mm_struct
*mm
= current
->active_mm
;
7384 BUG_ON(cpu_online(smp_processor_id()));
7387 switch_mm(mm
, &init_mm
, current
);
7391 /* called under rq->lock with disabled interrupts */
7392 static void migrate_dead(unsigned int dead_cpu
, struct task_struct
*p
)
7394 struct rq
*rq
= cpu_rq(dead_cpu
);
7396 /* Must be exiting, otherwise would be on tasklist. */
7397 BUG_ON(!p
->exit_state
);
7399 /* Cannot have done final schedule yet: would have vanished. */
7400 BUG_ON(p
->state
== TASK_DEAD
);
7405 * Drop lock around migration; if someone else moves it,
7406 * that's OK. No task can be added to this CPU, so iteration is
7409 raw_spin_unlock_irq(&rq
->lock
);
7410 move_task_off_dead_cpu(dead_cpu
, p
);
7411 raw_spin_lock_irq(&rq
->lock
);
7416 /* release_task() removes task from tasklist, so we won't find dead tasks. */
7417 static void migrate_dead_tasks(unsigned int dead_cpu
)
7419 struct rq
*rq
= cpu_rq(dead_cpu
);
7420 struct task_struct
*next
;
7423 if (!rq
->nr_running
)
7425 update_rq_clock(rq
);
7426 next
= pick_next_task(rq
);
7429 next
->sched_class
->put_prev_task(rq
, next
);
7430 migrate_dead(dead_cpu
, next
);
7436 * remove the tasks which were accounted by rq from calc_load_tasks.
7438 static void calc_global_load_remove(struct rq
*rq
)
7440 atomic_long_sub(rq
->calc_load_active
, &calc_load_tasks
);
7441 rq
->calc_load_active
= 0;
7443 #endif /* CONFIG_HOTPLUG_CPU */
7445 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
7447 static struct ctl_table sd_ctl_dir
[] = {
7449 .procname
= "sched_domain",
7455 static struct ctl_table sd_ctl_root
[] = {
7457 .procname
= "kernel",
7459 .child
= sd_ctl_dir
,
7464 static struct ctl_table
*sd_alloc_ctl_entry(int n
)
7466 struct ctl_table
*entry
=
7467 kcalloc(n
, sizeof(struct ctl_table
), GFP_KERNEL
);
7472 static void sd_free_ctl_entry(struct ctl_table
**tablep
)
7474 struct ctl_table
*entry
;
7477 * In the intermediate directories, both the child directory and
7478 * procname are dynamically allocated and could fail but the mode
7479 * will always be set. In the lowest directory the names are
7480 * static strings and all have proc handlers.
7482 for (entry
= *tablep
; entry
->mode
; entry
++) {
7484 sd_free_ctl_entry(&entry
->child
);
7485 if (entry
->proc_handler
== NULL
)
7486 kfree(entry
->procname
);
7494 set_table_entry(struct ctl_table
*entry
,
7495 const char *procname
, void *data
, int maxlen
,
7496 mode_t mode
, proc_handler
*proc_handler
)
7498 entry
->procname
= procname
;
7500 entry
->maxlen
= maxlen
;
7502 entry
->proc_handler
= proc_handler
;
7505 static struct ctl_table
*
7506 sd_alloc_ctl_domain_table(struct sched_domain
*sd
)
7508 struct ctl_table
*table
= sd_alloc_ctl_entry(13);
7513 set_table_entry(&table
[0], "min_interval", &sd
->min_interval
,
7514 sizeof(long), 0644, proc_doulongvec_minmax
);
7515 set_table_entry(&table
[1], "max_interval", &sd
->max_interval
,
7516 sizeof(long), 0644, proc_doulongvec_minmax
);
7517 set_table_entry(&table
[2], "busy_idx", &sd
->busy_idx
,
7518 sizeof(int), 0644, proc_dointvec_minmax
);
7519 set_table_entry(&table
[3], "idle_idx", &sd
->idle_idx
,
7520 sizeof(int), 0644, proc_dointvec_minmax
);
7521 set_table_entry(&table
[4], "newidle_idx", &sd
->newidle_idx
,
7522 sizeof(int), 0644, proc_dointvec_minmax
);
7523 set_table_entry(&table
[5], "wake_idx", &sd
->wake_idx
,
7524 sizeof(int), 0644, proc_dointvec_minmax
);
7525 set_table_entry(&table
[6], "forkexec_idx", &sd
->forkexec_idx
,
7526 sizeof(int), 0644, proc_dointvec_minmax
);
7527 set_table_entry(&table
[7], "busy_factor", &sd
->busy_factor
,
7528 sizeof(int), 0644, proc_dointvec_minmax
);
7529 set_table_entry(&table
[8], "imbalance_pct", &sd
->imbalance_pct
,
7530 sizeof(int), 0644, proc_dointvec_minmax
);
7531 set_table_entry(&table
[9], "cache_nice_tries",
7532 &sd
->cache_nice_tries
,
7533 sizeof(int), 0644, proc_dointvec_minmax
);
7534 set_table_entry(&table
[10], "flags", &sd
->flags
,
7535 sizeof(int), 0644, proc_dointvec_minmax
);
7536 set_table_entry(&table
[11], "name", sd
->name
,
7537 CORENAME_MAX_SIZE
, 0444, proc_dostring
);
7538 /* &table[12] is terminator */
7543 static ctl_table
*sd_alloc_ctl_cpu_table(int cpu
)
7545 struct ctl_table
*entry
, *table
;
7546 struct sched_domain
*sd
;
7547 int domain_num
= 0, i
;
7550 for_each_domain(cpu
, sd
)
7552 entry
= table
= sd_alloc_ctl_entry(domain_num
+ 1);
7557 for_each_domain(cpu
, sd
) {
7558 snprintf(buf
, 32, "domain%d", i
);
7559 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
7561 entry
->child
= sd_alloc_ctl_domain_table(sd
);
7568 static struct ctl_table_header
*sd_sysctl_header
;
7569 static void register_sched_domain_sysctl(void)
7571 int i
, cpu_num
= num_possible_cpus();
7572 struct ctl_table
*entry
= sd_alloc_ctl_entry(cpu_num
+ 1);
7575 WARN_ON(sd_ctl_dir
[0].child
);
7576 sd_ctl_dir
[0].child
= entry
;
7581 for_each_possible_cpu(i
) {
7582 snprintf(buf
, 32, "cpu%d", i
);
7583 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
7585 entry
->child
= sd_alloc_ctl_cpu_table(i
);
7589 WARN_ON(sd_sysctl_header
);
7590 sd_sysctl_header
= register_sysctl_table(sd_ctl_root
);
7593 /* may be called multiple times per register */
7594 static void unregister_sched_domain_sysctl(void)
7596 if (sd_sysctl_header
)
7597 unregister_sysctl_table(sd_sysctl_header
);
7598 sd_sysctl_header
= NULL
;
7599 if (sd_ctl_dir
[0].child
)
7600 sd_free_ctl_entry(&sd_ctl_dir
[0].child
);
7603 static void register_sched_domain_sysctl(void)
7606 static void unregister_sched_domain_sysctl(void)
7611 static void set_rq_online(struct rq
*rq
)
7614 const struct sched_class
*class;
7616 cpumask_set_cpu(rq
->cpu
, rq
->rd
->online
);
7619 for_each_class(class) {
7620 if (class->rq_online
)
7621 class->rq_online(rq
);
7626 static void set_rq_offline(struct rq
*rq
)
7629 const struct sched_class
*class;
7631 for_each_class(class) {
7632 if (class->rq_offline
)
7633 class->rq_offline(rq
);
7636 cpumask_clear_cpu(rq
->cpu
, rq
->rd
->online
);
7642 * migration_call - callback that gets triggered when a CPU is added.
7643 * Here we can start up the necessary migration thread for the new CPU.
7645 static int __cpuinit
7646 migration_call(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
7648 struct task_struct
*p
;
7649 int cpu
= (long)hcpu
;
7650 unsigned long flags
;
7655 case CPU_UP_PREPARE
:
7656 case CPU_UP_PREPARE_FROZEN
:
7657 p
= kthread_create(migration_thread
, hcpu
, "migration/%d", cpu
);
7660 kthread_bind(p
, cpu
);
7661 /* Must be high prio: stop_machine expects to yield to it. */
7662 rq
= task_rq_lock(p
, &flags
);
7663 __setscheduler(rq
, p
, SCHED_FIFO
, MAX_RT_PRIO
-1);
7664 task_rq_unlock(rq
, &flags
);
7666 cpu_rq(cpu
)->migration_thread
= p
;
7667 rq
->calc_load_update
= calc_load_update
;
7671 case CPU_ONLINE_FROZEN
:
7672 /* Strictly unnecessary, as first user will wake it. */
7673 wake_up_process(cpu_rq(cpu
)->migration_thread
);
7675 /* Update our root-domain */
7677 raw_spin_lock_irqsave(&rq
->lock
, flags
);
7679 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
7683 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
7686 #ifdef CONFIG_HOTPLUG_CPU
7687 case CPU_UP_CANCELED
:
7688 case CPU_UP_CANCELED_FROZEN
:
7689 if (!cpu_rq(cpu
)->migration_thread
)
7691 /* Unbind it from offline cpu so it can run. Fall thru. */
7692 kthread_bind(cpu_rq(cpu
)->migration_thread
,
7693 cpumask_any(cpu_online_mask
));
7694 kthread_stop(cpu_rq(cpu
)->migration_thread
);
7695 put_task_struct(cpu_rq(cpu
)->migration_thread
);
7696 cpu_rq(cpu
)->migration_thread
= NULL
;
7700 case CPU_DEAD_FROZEN
:
7701 cpuset_lock(); /* around calls to cpuset_cpus_allowed_lock() */
7702 migrate_live_tasks(cpu
);
7704 kthread_stop(rq
->migration_thread
);
7705 put_task_struct(rq
->migration_thread
);
7706 rq
->migration_thread
= NULL
;
7707 /* Idle task back to normal (off runqueue, low prio) */
7708 raw_spin_lock_irq(&rq
->lock
);
7709 update_rq_clock(rq
);
7710 deactivate_task(rq
, rq
->idle
, 0);
7711 __setscheduler(rq
, rq
->idle
, SCHED_NORMAL
, 0);
7712 rq
->idle
->sched_class
= &idle_sched_class
;
7713 migrate_dead_tasks(cpu
);
7714 raw_spin_unlock_irq(&rq
->lock
);
7716 migrate_nr_uninterruptible(rq
);
7717 BUG_ON(rq
->nr_running
!= 0);
7718 calc_global_load_remove(rq
);
7720 * No need to migrate the tasks: it was best-effort if
7721 * they didn't take sched_hotcpu_mutex. Just wake up
7724 raw_spin_lock_irq(&rq
->lock
);
7725 while (!list_empty(&rq
->migration_queue
)) {
7726 struct migration_req
*req
;
7728 req
= list_entry(rq
->migration_queue
.next
,
7729 struct migration_req
, list
);
7730 list_del_init(&req
->list
);
7731 raw_spin_unlock_irq(&rq
->lock
);
7732 complete(&req
->done
);
7733 raw_spin_lock_irq(&rq
->lock
);
7735 raw_spin_unlock_irq(&rq
->lock
);
7739 case CPU_DYING_FROZEN
:
7740 /* Update our root-domain */
7742 raw_spin_lock_irqsave(&rq
->lock
, flags
);
7744 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
7747 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
7755 * Register at high priority so that task migration (migrate_all_tasks)
7756 * happens before everything else. This has to be lower priority than
7757 * the notifier in the perf_event subsystem, though.
7759 static struct notifier_block __cpuinitdata migration_notifier
= {
7760 .notifier_call
= migration_call
,
7764 static int __init
migration_init(void)
7766 void *cpu
= (void *)(long)smp_processor_id();
7769 /* Start one for the boot CPU: */
7770 err
= migration_call(&migration_notifier
, CPU_UP_PREPARE
, cpu
);
7771 BUG_ON(err
== NOTIFY_BAD
);
7772 migration_call(&migration_notifier
, CPU_ONLINE
, cpu
);
7773 register_cpu_notifier(&migration_notifier
);
7777 early_initcall(migration_init
);
7782 #ifdef CONFIG_SCHED_DEBUG
7784 static __read_mostly
int sched_domain_debug_enabled
;
7786 static int __init
sched_domain_debug_setup(char *str
)
7788 sched_domain_debug_enabled
= 1;
7792 early_param("sched_debug", sched_domain_debug_setup
);
7794 static int sched_domain_debug_one(struct sched_domain
*sd
, int cpu
, int level
,
7795 struct cpumask
*groupmask
)
7797 struct sched_group
*group
= sd
->groups
;
7800 cpulist_scnprintf(str
, sizeof(str
), sched_domain_span(sd
));
7801 cpumask_clear(groupmask
);
7803 printk(KERN_DEBUG
"%*s domain %d: ", level
, "", level
);
7805 if (!(sd
->flags
& SD_LOAD_BALANCE
)) {
7806 pr_cont("does not load-balance\n");
7808 pr_err("ERROR: !SD_LOAD_BALANCE domain has parent\n");
7812 pr_cont("span %s level %s\n", str
, sd
->name
);
7814 if (!cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
7815 pr_err("ERROR: domain->span does not contain CPU%d\n", cpu
);
7817 if (!cpumask_test_cpu(cpu
, sched_group_cpus(group
))) {
7818 pr_err("ERROR: domain->groups does not contain CPU%d\n", cpu
);
7821 printk(KERN_DEBUG
"%*s groups:", level
+ 1, "");
7825 pr_err("ERROR: group is NULL\n");
7829 if (!group
->cpu_power
) {
7831 pr_err("ERROR: domain->cpu_power not set\n");
7835 if (!cpumask_weight(sched_group_cpus(group
))) {
7837 pr_err("ERROR: empty group\n");
7841 if (cpumask_intersects(groupmask
, sched_group_cpus(group
))) {
7843 pr_err("ERROR: repeated CPUs\n");
7847 cpumask_or(groupmask
, groupmask
, sched_group_cpus(group
));
7849 cpulist_scnprintf(str
, sizeof(str
), sched_group_cpus(group
));
7851 pr_cont(" %s", str
);
7852 if (group
->cpu_power
!= SCHED_LOAD_SCALE
) {
7853 pr_cont(" (cpu_power = %d)", group
->cpu_power
);
7856 group
= group
->next
;
7857 } while (group
!= sd
->groups
);
7860 if (!cpumask_equal(sched_domain_span(sd
), groupmask
))
7861 pr_err("ERROR: groups don't span domain->span\n");
7864 !cpumask_subset(groupmask
, sched_domain_span(sd
->parent
)))
7865 pr_err("ERROR: parent span is not a superset of domain->span\n");
7869 static void sched_domain_debug(struct sched_domain
*sd
, int cpu
)
7871 cpumask_var_t groupmask
;
7874 if (!sched_domain_debug_enabled
)
7878 printk(KERN_DEBUG
"CPU%d attaching NULL sched-domain.\n", cpu
);
7882 printk(KERN_DEBUG
"CPU%d attaching sched-domain:\n", cpu
);
7884 if (!alloc_cpumask_var(&groupmask
, GFP_KERNEL
)) {
7885 printk(KERN_DEBUG
"Cannot load-balance (out of memory)\n");
7890 if (sched_domain_debug_one(sd
, cpu
, level
, groupmask
))
7897 free_cpumask_var(groupmask
);
7899 #else /* !CONFIG_SCHED_DEBUG */
7900 # define sched_domain_debug(sd, cpu) do { } while (0)
7901 #endif /* CONFIG_SCHED_DEBUG */
7903 static int sd_degenerate(struct sched_domain
*sd
)
7905 if (cpumask_weight(sched_domain_span(sd
)) == 1)
7908 /* Following flags need at least 2 groups */
7909 if (sd
->flags
& (SD_LOAD_BALANCE
|
7910 SD_BALANCE_NEWIDLE
|
7914 SD_SHARE_PKG_RESOURCES
)) {
7915 if (sd
->groups
!= sd
->groups
->next
)
7919 /* Following flags don't use groups */
7920 if (sd
->flags
& (SD_WAKE_AFFINE
))
7927 sd_parent_degenerate(struct sched_domain
*sd
, struct sched_domain
*parent
)
7929 unsigned long cflags
= sd
->flags
, pflags
= parent
->flags
;
7931 if (sd_degenerate(parent
))
7934 if (!cpumask_equal(sched_domain_span(sd
), sched_domain_span(parent
)))
7937 /* Flags needing groups don't count if only 1 group in parent */
7938 if (parent
->groups
== parent
->groups
->next
) {
7939 pflags
&= ~(SD_LOAD_BALANCE
|
7940 SD_BALANCE_NEWIDLE
|
7944 SD_SHARE_PKG_RESOURCES
);
7945 if (nr_node_ids
== 1)
7946 pflags
&= ~SD_SERIALIZE
;
7948 if (~cflags
& pflags
)
7954 static void free_rootdomain(struct root_domain
*rd
)
7956 synchronize_sched();
7958 cpupri_cleanup(&rd
->cpupri
);
7960 free_cpumask_var(rd
->rto_mask
);
7961 free_cpumask_var(rd
->online
);
7962 free_cpumask_var(rd
->span
);
7966 static void rq_attach_root(struct rq
*rq
, struct root_domain
*rd
)
7968 struct root_domain
*old_rd
= NULL
;
7969 unsigned long flags
;
7971 raw_spin_lock_irqsave(&rq
->lock
, flags
);
7976 if (cpumask_test_cpu(rq
->cpu
, old_rd
->online
))
7979 cpumask_clear_cpu(rq
->cpu
, old_rd
->span
);
7982 * If we dont want to free the old_rt yet then
7983 * set old_rd to NULL to skip the freeing later
7986 if (!atomic_dec_and_test(&old_rd
->refcount
))
7990 atomic_inc(&rd
->refcount
);
7993 cpumask_set_cpu(rq
->cpu
, rd
->span
);
7994 if (cpumask_test_cpu(rq
->cpu
, cpu_active_mask
))
7997 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
8000 free_rootdomain(old_rd
);
8003 static int init_rootdomain(struct root_domain
*rd
, bool bootmem
)
8005 gfp_t gfp
= GFP_KERNEL
;
8007 memset(rd
, 0, sizeof(*rd
));
8012 if (!alloc_cpumask_var(&rd
->span
, gfp
))
8014 if (!alloc_cpumask_var(&rd
->online
, gfp
))
8016 if (!alloc_cpumask_var(&rd
->rto_mask
, gfp
))
8019 if (cpupri_init(&rd
->cpupri
, bootmem
) != 0)
8024 free_cpumask_var(rd
->rto_mask
);
8026 free_cpumask_var(rd
->online
);
8028 free_cpumask_var(rd
->span
);
8033 static void init_defrootdomain(void)
8035 init_rootdomain(&def_root_domain
, true);
8037 atomic_set(&def_root_domain
.refcount
, 1);
8040 static struct root_domain
*alloc_rootdomain(void)
8042 struct root_domain
*rd
;
8044 rd
= kmalloc(sizeof(*rd
), GFP_KERNEL
);
8048 if (init_rootdomain(rd
, false) != 0) {
8057 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
8058 * hold the hotplug lock.
8061 cpu_attach_domain(struct sched_domain
*sd
, struct root_domain
*rd
, int cpu
)
8063 struct rq
*rq
= cpu_rq(cpu
);
8064 struct sched_domain
*tmp
;
8066 /* Remove the sched domains which do not contribute to scheduling. */
8067 for (tmp
= sd
; tmp
; ) {
8068 struct sched_domain
*parent
= tmp
->parent
;
8072 if (sd_parent_degenerate(tmp
, parent
)) {
8073 tmp
->parent
= parent
->parent
;
8075 parent
->parent
->child
= tmp
;
8080 if (sd
&& sd_degenerate(sd
)) {
8086 sched_domain_debug(sd
, cpu
);
8088 rq_attach_root(rq
, rd
);
8089 rcu_assign_pointer(rq
->sd
, sd
);
8092 /* cpus with isolated domains */
8093 static cpumask_var_t cpu_isolated_map
;
8095 /* Setup the mask of cpus configured for isolated domains */
8096 static int __init
isolated_cpu_setup(char *str
)
8098 alloc_bootmem_cpumask_var(&cpu_isolated_map
);
8099 cpulist_parse(str
, cpu_isolated_map
);
8103 __setup("isolcpus=", isolated_cpu_setup
);
8106 * init_sched_build_groups takes the cpumask we wish to span, and a pointer
8107 * to a function which identifies what group(along with sched group) a CPU
8108 * belongs to. The return value of group_fn must be a >= 0 and < nr_cpu_ids
8109 * (due to the fact that we keep track of groups covered with a struct cpumask).
8111 * init_sched_build_groups will build a circular linked list of the groups
8112 * covered by the given span, and will set each group's ->cpumask correctly,
8113 * and ->cpu_power to 0.
8116 init_sched_build_groups(const struct cpumask
*span
,
8117 const struct cpumask
*cpu_map
,
8118 int (*group_fn
)(int cpu
, const struct cpumask
*cpu_map
,
8119 struct sched_group
**sg
,
8120 struct cpumask
*tmpmask
),
8121 struct cpumask
*covered
, struct cpumask
*tmpmask
)
8123 struct sched_group
*first
= NULL
, *last
= NULL
;
8126 cpumask_clear(covered
);
8128 for_each_cpu(i
, span
) {
8129 struct sched_group
*sg
;
8130 int group
= group_fn(i
, cpu_map
, &sg
, tmpmask
);
8133 if (cpumask_test_cpu(i
, covered
))
8136 cpumask_clear(sched_group_cpus(sg
));
8139 for_each_cpu(j
, span
) {
8140 if (group_fn(j
, cpu_map
, NULL
, tmpmask
) != group
)
8143 cpumask_set_cpu(j
, covered
);
8144 cpumask_set_cpu(j
, sched_group_cpus(sg
));
8155 #define SD_NODES_PER_DOMAIN 16
8160 * find_next_best_node - find the next node to include in a sched_domain
8161 * @node: node whose sched_domain we're building
8162 * @used_nodes: nodes already in the sched_domain
8164 * Find the next node to include in a given scheduling domain. Simply
8165 * finds the closest node not already in the @used_nodes map.
8167 * Should use nodemask_t.
8169 static int find_next_best_node(int node
, nodemask_t
*used_nodes
)
8171 int i
, n
, val
, min_val
, best_node
= 0;
8175 for (i
= 0; i
< nr_node_ids
; i
++) {
8176 /* Start at @node */
8177 n
= (node
+ i
) % nr_node_ids
;
8179 if (!nr_cpus_node(n
))
8182 /* Skip already used nodes */
8183 if (node_isset(n
, *used_nodes
))
8186 /* Simple min distance search */
8187 val
= node_distance(node
, n
);
8189 if (val
< min_val
) {
8195 node_set(best_node
, *used_nodes
);
8200 * sched_domain_node_span - get a cpumask for a node's sched_domain
8201 * @node: node whose cpumask we're constructing
8202 * @span: resulting cpumask
8204 * Given a node, construct a good cpumask for its sched_domain to span. It
8205 * should be one that prevents unnecessary balancing, but also spreads tasks
8208 static void sched_domain_node_span(int node
, struct cpumask
*span
)
8210 nodemask_t used_nodes
;
8213 cpumask_clear(span
);
8214 nodes_clear(used_nodes
);
8216 cpumask_or(span
, span
, cpumask_of_node(node
));
8217 node_set(node
, used_nodes
);
8219 for (i
= 1; i
< SD_NODES_PER_DOMAIN
; i
++) {
8220 int next_node
= find_next_best_node(node
, &used_nodes
);
8222 cpumask_or(span
, span
, cpumask_of_node(next_node
));
8225 #endif /* CONFIG_NUMA */
8227 int sched_smt_power_savings
= 0, sched_mc_power_savings
= 0;
8230 * The cpus mask in sched_group and sched_domain hangs off the end.
8232 * ( See the the comments in include/linux/sched.h:struct sched_group
8233 * and struct sched_domain. )
8235 struct static_sched_group
{
8236 struct sched_group sg
;
8237 DECLARE_BITMAP(cpus
, CONFIG_NR_CPUS
);
8240 struct static_sched_domain
{
8241 struct sched_domain sd
;
8242 DECLARE_BITMAP(span
, CONFIG_NR_CPUS
);
8248 cpumask_var_t domainspan
;
8249 cpumask_var_t covered
;
8250 cpumask_var_t notcovered
;
8252 cpumask_var_t nodemask
;
8253 cpumask_var_t this_sibling_map
;
8254 cpumask_var_t this_core_map
;
8255 cpumask_var_t send_covered
;
8256 cpumask_var_t tmpmask
;
8257 struct sched_group
**sched_group_nodes
;
8258 struct root_domain
*rd
;
8262 sa_sched_groups
= 0,
8267 sa_this_sibling_map
,
8269 sa_sched_group_nodes
,
8279 * SMT sched-domains:
8281 #ifdef CONFIG_SCHED_SMT
8282 static DEFINE_PER_CPU(struct static_sched_domain
, cpu_domains
);
8283 static DEFINE_PER_CPU(struct static_sched_group
, sched_groups
);
8286 cpu_to_cpu_group(int cpu
, const struct cpumask
*cpu_map
,
8287 struct sched_group
**sg
, struct cpumask
*unused
)
8290 *sg
= &per_cpu(sched_groups
, cpu
).sg
;
8293 #endif /* CONFIG_SCHED_SMT */
8296 * multi-core sched-domains:
8298 #ifdef CONFIG_SCHED_MC
8299 static DEFINE_PER_CPU(struct static_sched_domain
, core_domains
);
8300 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_core
);
8301 #endif /* CONFIG_SCHED_MC */
8303 #if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT)
8305 cpu_to_core_group(int cpu
, const struct cpumask
*cpu_map
,
8306 struct sched_group
**sg
, struct cpumask
*mask
)
8310 cpumask_and(mask
, topology_thread_cpumask(cpu
), cpu_map
);
8311 group
= cpumask_first(mask
);
8313 *sg
= &per_cpu(sched_group_core
, group
).sg
;
8316 #elif defined(CONFIG_SCHED_MC)
8318 cpu_to_core_group(int cpu
, const struct cpumask
*cpu_map
,
8319 struct sched_group
**sg
, struct cpumask
*unused
)
8322 *sg
= &per_cpu(sched_group_core
, cpu
).sg
;
8327 static DEFINE_PER_CPU(struct static_sched_domain
, phys_domains
);
8328 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_phys
);
8331 cpu_to_phys_group(int cpu
, const struct cpumask
*cpu_map
,
8332 struct sched_group
**sg
, struct cpumask
*mask
)
8335 #ifdef CONFIG_SCHED_MC
8336 cpumask_and(mask
, cpu_coregroup_mask(cpu
), cpu_map
);
8337 group
= cpumask_first(mask
);
8338 #elif defined(CONFIG_SCHED_SMT)
8339 cpumask_and(mask
, topology_thread_cpumask(cpu
), cpu_map
);
8340 group
= cpumask_first(mask
);
8345 *sg
= &per_cpu(sched_group_phys
, group
).sg
;
8351 * The init_sched_build_groups can't handle what we want to do with node
8352 * groups, so roll our own. Now each node has its own list of groups which
8353 * gets dynamically allocated.
8355 static DEFINE_PER_CPU(struct static_sched_domain
, node_domains
);
8356 static struct sched_group
***sched_group_nodes_bycpu
;
8358 static DEFINE_PER_CPU(struct static_sched_domain
, allnodes_domains
);
8359 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_allnodes
);
8361 static int cpu_to_allnodes_group(int cpu
, const struct cpumask
*cpu_map
,
8362 struct sched_group
**sg
,
8363 struct cpumask
*nodemask
)
8367 cpumask_and(nodemask
, cpumask_of_node(cpu_to_node(cpu
)), cpu_map
);
8368 group
= cpumask_first(nodemask
);
8371 *sg
= &per_cpu(sched_group_allnodes
, group
).sg
;
8375 static void init_numa_sched_groups_power(struct sched_group
*group_head
)
8377 struct sched_group
*sg
= group_head
;
8383 for_each_cpu(j
, sched_group_cpus(sg
)) {
8384 struct sched_domain
*sd
;
8386 sd
= &per_cpu(phys_domains
, j
).sd
;
8387 if (j
!= group_first_cpu(sd
->groups
)) {
8389 * Only add "power" once for each
8395 sg
->cpu_power
+= sd
->groups
->cpu_power
;
8398 } while (sg
!= group_head
);
8401 static int build_numa_sched_groups(struct s_data
*d
,
8402 const struct cpumask
*cpu_map
, int num
)
8404 struct sched_domain
*sd
;
8405 struct sched_group
*sg
, *prev
;
8408 cpumask_clear(d
->covered
);
8409 cpumask_and(d
->nodemask
, cpumask_of_node(num
), cpu_map
);
8410 if (cpumask_empty(d
->nodemask
)) {
8411 d
->sched_group_nodes
[num
] = NULL
;
8415 sched_domain_node_span(num
, d
->domainspan
);
8416 cpumask_and(d
->domainspan
, d
->domainspan
, cpu_map
);
8418 sg
= kmalloc_node(sizeof(struct sched_group
) + cpumask_size(),
8421 pr_warning("Can not alloc domain group for node %d\n", num
);
8424 d
->sched_group_nodes
[num
] = sg
;
8426 for_each_cpu(j
, d
->nodemask
) {
8427 sd
= &per_cpu(node_domains
, j
).sd
;
8432 cpumask_copy(sched_group_cpus(sg
), d
->nodemask
);
8434 cpumask_or(d
->covered
, d
->covered
, d
->nodemask
);
8437 for (j
= 0; j
< nr_node_ids
; j
++) {
8438 n
= (num
+ j
) % nr_node_ids
;
8439 cpumask_complement(d
->notcovered
, d
->covered
);
8440 cpumask_and(d
->tmpmask
, d
->notcovered
, cpu_map
);
8441 cpumask_and(d
->tmpmask
, d
->tmpmask
, d
->domainspan
);
8442 if (cpumask_empty(d
->tmpmask
))
8444 cpumask_and(d
->tmpmask
, d
->tmpmask
, cpumask_of_node(n
));
8445 if (cpumask_empty(d
->tmpmask
))
8447 sg
= kmalloc_node(sizeof(struct sched_group
) + cpumask_size(),
8450 pr_warning("Can not alloc domain group for node %d\n",
8455 cpumask_copy(sched_group_cpus(sg
), d
->tmpmask
);
8456 sg
->next
= prev
->next
;
8457 cpumask_or(d
->covered
, d
->covered
, d
->tmpmask
);
8464 #endif /* CONFIG_NUMA */
8467 /* Free memory allocated for various sched_group structures */
8468 static void free_sched_groups(const struct cpumask
*cpu_map
,
8469 struct cpumask
*nodemask
)
8473 for_each_cpu(cpu
, cpu_map
) {
8474 struct sched_group
**sched_group_nodes
8475 = sched_group_nodes_bycpu
[cpu
];
8477 if (!sched_group_nodes
)
8480 for (i
= 0; i
< nr_node_ids
; i
++) {
8481 struct sched_group
*oldsg
, *sg
= sched_group_nodes
[i
];
8483 cpumask_and(nodemask
, cpumask_of_node(i
), cpu_map
);
8484 if (cpumask_empty(nodemask
))
8494 if (oldsg
!= sched_group_nodes
[i
])
8497 kfree(sched_group_nodes
);
8498 sched_group_nodes_bycpu
[cpu
] = NULL
;
8501 #else /* !CONFIG_NUMA */
8502 static void free_sched_groups(const struct cpumask
*cpu_map
,
8503 struct cpumask
*nodemask
)
8506 #endif /* CONFIG_NUMA */
8509 * Initialize sched groups cpu_power.
8511 * cpu_power indicates the capacity of sched group, which is used while
8512 * distributing the load between different sched groups in a sched domain.
8513 * Typically cpu_power for all the groups in a sched domain will be same unless
8514 * there are asymmetries in the topology. If there are asymmetries, group
8515 * having more cpu_power will pickup more load compared to the group having
8518 static void init_sched_groups_power(int cpu
, struct sched_domain
*sd
)
8520 struct sched_domain
*child
;
8521 struct sched_group
*group
;
8525 WARN_ON(!sd
|| !sd
->groups
);
8527 if (cpu
!= group_first_cpu(sd
->groups
))
8532 sd
->groups
->cpu_power
= 0;
8535 power
= SCHED_LOAD_SCALE
;
8536 weight
= cpumask_weight(sched_domain_span(sd
));
8538 * SMT siblings share the power of a single core.
8539 * Usually multiple threads get a better yield out of
8540 * that one core than a single thread would have,
8541 * reflect that in sd->smt_gain.
8543 if ((sd
->flags
& SD_SHARE_CPUPOWER
) && weight
> 1) {
8544 power
*= sd
->smt_gain
;
8546 power
>>= SCHED_LOAD_SHIFT
;
8548 sd
->groups
->cpu_power
+= power
;
8553 * Add cpu_power of each child group to this groups cpu_power.
8555 group
= child
->groups
;
8557 sd
->groups
->cpu_power
+= group
->cpu_power
;
8558 group
= group
->next
;
8559 } while (group
!= child
->groups
);
8563 * Initializers for schedule domains
8564 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
8567 #ifdef CONFIG_SCHED_DEBUG
8568 # define SD_INIT_NAME(sd, type) sd->name = #type
8570 # define SD_INIT_NAME(sd, type) do { } while (0)
8573 #define SD_INIT(sd, type) sd_init_##type(sd)
8575 #define SD_INIT_FUNC(type) \
8576 static noinline void sd_init_##type(struct sched_domain *sd) \
8578 memset(sd, 0, sizeof(*sd)); \
8579 *sd = SD_##type##_INIT; \
8580 sd->level = SD_LV_##type; \
8581 SD_INIT_NAME(sd, type); \
8586 SD_INIT_FUNC(ALLNODES
)
8589 #ifdef CONFIG_SCHED_SMT
8590 SD_INIT_FUNC(SIBLING
)
8592 #ifdef CONFIG_SCHED_MC
8596 static int default_relax_domain_level
= -1;
8598 static int __init
setup_relax_domain_level(char *str
)
8602 val
= simple_strtoul(str
, NULL
, 0);
8603 if (val
< SD_LV_MAX
)
8604 default_relax_domain_level
= val
;
8608 __setup("relax_domain_level=", setup_relax_domain_level
);
8610 static void set_domain_attribute(struct sched_domain
*sd
,
8611 struct sched_domain_attr
*attr
)
8615 if (!attr
|| attr
->relax_domain_level
< 0) {
8616 if (default_relax_domain_level
< 0)
8619 request
= default_relax_domain_level
;
8621 request
= attr
->relax_domain_level
;
8622 if (request
< sd
->level
) {
8623 /* turn off idle balance on this domain */
8624 sd
->flags
&= ~(SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
8626 /* turn on idle balance on this domain */
8627 sd
->flags
|= (SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
8631 static void __free_domain_allocs(struct s_data
*d
, enum s_alloc what
,
8632 const struct cpumask
*cpu_map
)
8635 case sa_sched_groups
:
8636 free_sched_groups(cpu_map
, d
->tmpmask
); /* fall through */
8637 d
->sched_group_nodes
= NULL
;
8639 free_rootdomain(d
->rd
); /* fall through */
8641 free_cpumask_var(d
->tmpmask
); /* fall through */
8642 case sa_send_covered
:
8643 free_cpumask_var(d
->send_covered
); /* fall through */
8644 case sa_this_core_map
:
8645 free_cpumask_var(d
->this_core_map
); /* fall through */
8646 case sa_this_sibling_map
:
8647 free_cpumask_var(d
->this_sibling_map
); /* fall through */
8649 free_cpumask_var(d
->nodemask
); /* fall through */
8650 case sa_sched_group_nodes
:
8652 kfree(d
->sched_group_nodes
); /* fall through */
8654 free_cpumask_var(d
->notcovered
); /* fall through */
8656 free_cpumask_var(d
->covered
); /* fall through */
8658 free_cpumask_var(d
->domainspan
); /* fall through */
8665 static enum s_alloc
__visit_domain_allocation_hell(struct s_data
*d
,
8666 const struct cpumask
*cpu_map
)
8669 if (!alloc_cpumask_var(&d
->domainspan
, GFP_KERNEL
))
8671 if (!alloc_cpumask_var(&d
->covered
, GFP_KERNEL
))
8672 return sa_domainspan
;
8673 if (!alloc_cpumask_var(&d
->notcovered
, GFP_KERNEL
))
8675 /* Allocate the per-node list of sched groups */
8676 d
->sched_group_nodes
= kcalloc(nr_node_ids
,
8677 sizeof(struct sched_group
*), GFP_KERNEL
);
8678 if (!d
->sched_group_nodes
) {
8679 pr_warning("Can not alloc sched group node list\n");
8680 return sa_notcovered
;
8682 sched_group_nodes_bycpu
[cpumask_first(cpu_map
)] = d
->sched_group_nodes
;
8684 if (!alloc_cpumask_var(&d
->nodemask
, GFP_KERNEL
))
8685 return sa_sched_group_nodes
;
8686 if (!alloc_cpumask_var(&d
->this_sibling_map
, GFP_KERNEL
))
8688 if (!alloc_cpumask_var(&d
->this_core_map
, GFP_KERNEL
))
8689 return sa_this_sibling_map
;
8690 if (!alloc_cpumask_var(&d
->send_covered
, GFP_KERNEL
))
8691 return sa_this_core_map
;
8692 if (!alloc_cpumask_var(&d
->tmpmask
, GFP_KERNEL
))
8693 return sa_send_covered
;
8694 d
->rd
= alloc_rootdomain();
8696 pr_warning("Cannot alloc root domain\n");
8699 return sa_rootdomain
;
8702 static struct sched_domain
*__build_numa_sched_domains(struct s_data
*d
,
8703 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
, int i
)
8705 struct sched_domain
*sd
= NULL
;
8707 struct sched_domain
*parent
;
8710 if (cpumask_weight(cpu_map
) >
8711 SD_NODES_PER_DOMAIN
* cpumask_weight(d
->nodemask
)) {
8712 sd
= &per_cpu(allnodes_domains
, i
).sd
;
8713 SD_INIT(sd
, ALLNODES
);
8714 set_domain_attribute(sd
, attr
);
8715 cpumask_copy(sched_domain_span(sd
), cpu_map
);
8716 cpu_to_allnodes_group(i
, cpu_map
, &sd
->groups
, d
->tmpmask
);
8721 sd
= &per_cpu(node_domains
, i
).sd
;
8723 set_domain_attribute(sd
, attr
);
8724 sched_domain_node_span(cpu_to_node(i
), sched_domain_span(sd
));
8725 sd
->parent
= parent
;
8728 cpumask_and(sched_domain_span(sd
), sched_domain_span(sd
), cpu_map
);
8733 static struct sched_domain
*__build_cpu_sched_domain(struct s_data
*d
,
8734 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
,
8735 struct sched_domain
*parent
, int i
)
8737 struct sched_domain
*sd
;
8738 sd
= &per_cpu(phys_domains
, i
).sd
;
8740 set_domain_attribute(sd
, attr
);
8741 cpumask_copy(sched_domain_span(sd
), d
->nodemask
);
8742 sd
->parent
= parent
;
8745 cpu_to_phys_group(i
, cpu_map
, &sd
->groups
, d
->tmpmask
);
8749 static struct sched_domain
*__build_mc_sched_domain(struct s_data
*d
,
8750 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
,
8751 struct sched_domain
*parent
, int i
)
8753 struct sched_domain
*sd
= parent
;
8754 #ifdef CONFIG_SCHED_MC
8755 sd
= &per_cpu(core_domains
, i
).sd
;
8757 set_domain_attribute(sd
, attr
);
8758 cpumask_and(sched_domain_span(sd
), cpu_map
, cpu_coregroup_mask(i
));
8759 sd
->parent
= parent
;
8761 cpu_to_core_group(i
, cpu_map
, &sd
->groups
, d
->tmpmask
);
8766 static struct sched_domain
*__build_smt_sched_domain(struct s_data
*d
,
8767 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
,
8768 struct sched_domain
*parent
, int i
)
8770 struct sched_domain
*sd
= parent
;
8771 #ifdef CONFIG_SCHED_SMT
8772 sd
= &per_cpu(cpu_domains
, i
).sd
;
8773 SD_INIT(sd
, SIBLING
);
8774 set_domain_attribute(sd
, attr
);
8775 cpumask_and(sched_domain_span(sd
), cpu_map
, topology_thread_cpumask(i
));
8776 sd
->parent
= parent
;
8778 cpu_to_cpu_group(i
, cpu_map
, &sd
->groups
, d
->tmpmask
);
8783 static void build_sched_groups(struct s_data
*d
, enum sched_domain_level l
,
8784 const struct cpumask
*cpu_map
, int cpu
)
8787 #ifdef CONFIG_SCHED_SMT
8788 case SD_LV_SIBLING
: /* set up CPU (sibling) groups */
8789 cpumask_and(d
->this_sibling_map
, cpu_map
,
8790 topology_thread_cpumask(cpu
));
8791 if (cpu
== cpumask_first(d
->this_sibling_map
))
8792 init_sched_build_groups(d
->this_sibling_map
, cpu_map
,
8794 d
->send_covered
, d
->tmpmask
);
8797 #ifdef CONFIG_SCHED_MC
8798 case SD_LV_MC
: /* set up multi-core groups */
8799 cpumask_and(d
->this_core_map
, cpu_map
, cpu_coregroup_mask(cpu
));
8800 if (cpu
== cpumask_first(d
->this_core_map
))
8801 init_sched_build_groups(d
->this_core_map
, cpu_map
,
8803 d
->send_covered
, d
->tmpmask
);
8806 case SD_LV_CPU
: /* set up physical groups */
8807 cpumask_and(d
->nodemask
, cpumask_of_node(cpu
), cpu_map
);
8808 if (!cpumask_empty(d
->nodemask
))
8809 init_sched_build_groups(d
->nodemask
, cpu_map
,
8811 d
->send_covered
, d
->tmpmask
);
8814 case SD_LV_ALLNODES
:
8815 init_sched_build_groups(cpu_map
, cpu_map
, &cpu_to_allnodes_group
,
8816 d
->send_covered
, d
->tmpmask
);
8825 * Build sched domains for a given set of cpus and attach the sched domains
8826 * to the individual cpus
8828 static int __build_sched_domains(const struct cpumask
*cpu_map
,
8829 struct sched_domain_attr
*attr
)
8831 enum s_alloc alloc_state
= sa_none
;
8833 struct sched_domain
*sd
;
8839 alloc_state
= __visit_domain_allocation_hell(&d
, cpu_map
);
8840 if (alloc_state
!= sa_rootdomain
)
8842 alloc_state
= sa_sched_groups
;
8845 * Set up domains for cpus specified by the cpu_map.
8847 for_each_cpu(i
, cpu_map
) {
8848 cpumask_and(d
.nodemask
, cpumask_of_node(cpu_to_node(i
)),
8851 sd
= __build_numa_sched_domains(&d
, cpu_map
, attr
, i
);
8852 sd
= __build_cpu_sched_domain(&d
, cpu_map
, attr
, sd
, i
);
8853 sd
= __build_mc_sched_domain(&d
, cpu_map
, attr
, sd
, i
);
8854 sd
= __build_smt_sched_domain(&d
, cpu_map
, attr
, sd
, i
);
8857 for_each_cpu(i
, cpu_map
) {
8858 build_sched_groups(&d
, SD_LV_SIBLING
, cpu_map
, i
);
8859 build_sched_groups(&d
, SD_LV_MC
, cpu_map
, i
);
8862 /* Set up physical groups */
8863 for (i
= 0; i
< nr_node_ids
; i
++)
8864 build_sched_groups(&d
, SD_LV_CPU
, cpu_map
, i
);
8867 /* Set up node groups */
8869 build_sched_groups(&d
, SD_LV_ALLNODES
, cpu_map
, 0);
8871 for (i
= 0; i
< nr_node_ids
; i
++)
8872 if (build_numa_sched_groups(&d
, cpu_map
, i
))
8876 /* Calculate CPU power for physical packages and nodes */
8877 #ifdef CONFIG_SCHED_SMT
8878 for_each_cpu(i
, cpu_map
) {
8879 sd
= &per_cpu(cpu_domains
, i
).sd
;
8880 init_sched_groups_power(i
, sd
);
8883 #ifdef CONFIG_SCHED_MC
8884 for_each_cpu(i
, cpu_map
) {
8885 sd
= &per_cpu(core_domains
, i
).sd
;
8886 init_sched_groups_power(i
, sd
);
8890 for_each_cpu(i
, cpu_map
) {
8891 sd
= &per_cpu(phys_domains
, i
).sd
;
8892 init_sched_groups_power(i
, sd
);
8896 for (i
= 0; i
< nr_node_ids
; i
++)
8897 init_numa_sched_groups_power(d
.sched_group_nodes
[i
]);
8899 if (d
.sd_allnodes
) {
8900 struct sched_group
*sg
;
8902 cpu_to_allnodes_group(cpumask_first(cpu_map
), cpu_map
, &sg
,
8904 init_numa_sched_groups_power(sg
);
8908 /* Attach the domains */
8909 for_each_cpu(i
, cpu_map
) {
8910 #ifdef CONFIG_SCHED_SMT
8911 sd
= &per_cpu(cpu_domains
, i
).sd
;
8912 #elif defined(CONFIG_SCHED_MC)
8913 sd
= &per_cpu(core_domains
, i
).sd
;
8915 sd
= &per_cpu(phys_domains
, i
).sd
;
8917 cpu_attach_domain(sd
, d
.rd
, i
);
8920 d
.sched_group_nodes
= NULL
; /* don't free this we still need it */
8921 __free_domain_allocs(&d
, sa_tmpmask
, cpu_map
);
8925 __free_domain_allocs(&d
, alloc_state
, cpu_map
);
8929 static int build_sched_domains(const struct cpumask
*cpu_map
)
8931 return __build_sched_domains(cpu_map
, NULL
);
8934 static cpumask_var_t
*doms_cur
; /* current sched domains */
8935 static int ndoms_cur
; /* number of sched domains in 'doms_cur' */
8936 static struct sched_domain_attr
*dattr_cur
;
8937 /* attribues of custom domains in 'doms_cur' */
8940 * Special case: If a kmalloc of a doms_cur partition (array of
8941 * cpumask) fails, then fallback to a single sched domain,
8942 * as determined by the single cpumask fallback_doms.
8944 static cpumask_var_t fallback_doms
;
8947 * arch_update_cpu_topology lets virtualized architectures update the
8948 * cpu core maps. It is supposed to return 1 if the topology changed
8949 * or 0 if it stayed the same.
8951 int __attribute__((weak
)) arch_update_cpu_topology(void)
8956 cpumask_var_t
*alloc_sched_domains(unsigned int ndoms
)
8959 cpumask_var_t
*doms
;
8961 doms
= kmalloc(sizeof(*doms
) * ndoms
, GFP_KERNEL
);
8964 for (i
= 0; i
< ndoms
; i
++) {
8965 if (!alloc_cpumask_var(&doms
[i
], GFP_KERNEL
)) {
8966 free_sched_domains(doms
, i
);
8973 void free_sched_domains(cpumask_var_t doms
[], unsigned int ndoms
)
8976 for (i
= 0; i
< ndoms
; i
++)
8977 free_cpumask_var(doms
[i
]);
8982 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
8983 * For now this just excludes isolated cpus, but could be used to
8984 * exclude other special cases in the future.
8986 static int arch_init_sched_domains(const struct cpumask
*cpu_map
)
8990 arch_update_cpu_topology();
8992 doms_cur
= alloc_sched_domains(ndoms_cur
);
8994 doms_cur
= &fallback_doms
;
8995 cpumask_andnot(doms_cur
[0], cpu_map
, cpu_isolated_map
);
8997 err
= build_sched_domains(doms_cur
[0]);
8998 register_sched_domain_sysctl();
9003 static void arch_destroy_sched_domains(const struct cpumask
*cpu_map
,
9004 struct cpumask
*tmpmask
)
9006 free_sched_groups(cpu_map
, tmpmask
);
9010 * Detach sched domains from a group of cpus specified in cpu_map
9011 * These cpus will now be attached to the NULL domain
9013 static void detach_destroy_domains(const struct cpumask
*cpu_map
)
9015 /* Save because hotplug lock held. */
9016 static DECLARE_BITMAP(tmpmask
, CONFIG_NR_CPUS
);
9019 for_each_cpu(i
, cpu_map
)
9020 cpu_attach_domain(NULL
, &def_root_domain
, i
);
9021 synchronize_sched();
9022 arch_destroy_sched_domains(cpu_map
, to_cpumask(tmpmask
));
9025 /* handle null as "default" */
9026 static int dattrs_equal(struct sched_domain_attr
*cur
, int idx_cur
,
9027 struct sched_domain_attr
*new, int idx_new
)
9029 struct sched_domain_attr tmp
;
9036 return !memcmp(cur
? (cur
+ idx_cur
) : &tmp
,
9037 new ? (new + idx_new
) : &tmp
,
9038 sizeof(struct sched_domain_attr
));
9042 * Partition sched domains as specified by the 'ndoms_new'
9043 * cpumasks in the array doms_new[] of cpumasks. This compares
9044 * doms_new[] to the current sched domain partitioning, doms_cur[].
9045 * It destroys each deleted domain and builds each new domain.
9047 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'.
9048 * The masks don't intersect (don't overlap.) We should setup one
9049 * sched domain for each mask. CPUs not in any of the cpumasks will
9050 * not be load balanced. If the same cpumask appears both in the
9051 * current 'doms_cur' domains and in the new 'doms_new', we can leave
9054 * The passed in 'doms_new' should be allocated using
9055 * alloc_sched_domains. This routine takes ownership of it and will
9056 * free_sched_domains it when done with it. If the caller failed the
9057 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1,
9058 * and partition_sched_domains() will fallback to the single partition
9059 * 'fallback_doms', it also forces the domains to be rebuilt.
9061 * If doms_new == NULL it will be replaced with cpu_online_mask.
9062 * ndoms_new == 0 is a special case for destroying existing domains,
9063 * and it will not create the default domain.
9065 * Call with hotplug lock held
9067 void partition_sched_domains(int ndoms_new
, cpumask_var_t doms_new
[],
9068 struct sched_domain_attr
*dattr_new
)
9073 mutex_lock(&sched_domains_mutex
);
9075 /* always unregister in case we don't destroy any domains */
9076 unregister_sched_domain_sysctl();
9078 /* Let architecture update cpu core mappings. */
9079 new_topology
= arch_update_cpu_topology();
9081 n
= doms_new
? ndoms_new
: 0;
9083 /* Destroy deleted domains */
9084 for (i
= 0; i
< ndoms_cur
; i
++) {
9085 for (j
= 0; j
< n
&& !new_topology
; j
++) {
9086 if (cpumask_equal(doms_cur
[i
], doms_new
[j
])
9087 && dattrs_equal(dattr_cur
, i
, dattr_new
, j
))
9090 /* no match - a current sched domain not in new doms_new[] */
9091 detach_destroy_domains(doms_cur
[i
]);
9096 if (doms_new
== NULL
) {
9098 doms_new
= &fallback_doms
;
9099 cpumask_andnot(doms_new
[0], cpu_active_mask
, cpu_isolated_map
);
9100 WARN_ON_ONCE(dattr_new
);
9103 /* Build new domains */
9104 for (i
= 0; i
< ndoms_new
; i
++) {
9105 for (j
= 0; j
< ndoms_cur
&& !new_topology
; j
++) {
9106 if (cpumask_equal(doms_new
[i
], doms_cur
[j
])
9107 && dattrs_equal(dattr_new
, i
, dattr_cur
, j
))
9110 /* no match - add a new doms_new */
9111 __build_sched_domains(doms_new
[i
],
9112 dattr_new
? dattr_new
+ i
: NULL
);
9117 /* Remember the new sched domains */
9118 if (doms_cur
!= &fallback_doms
)
9119 free_sched_domains(doms_cur
, ndoms_cur
);
9120 kfree(dattr_cur
); /* kfree(NULL) is safe */
9121 doms_cur
= doms_new
;
9122 dattr_cur
= dattr_new
;
9123 ndoms_cur
= ndoms_new
;
9125 register_sched_domain_sysctl();
9127 mutex_unlock(&sched_domains_mutex
);
9130 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
9131 static void arch_reinit_sched_domains(void)
9135 /* Destroy domains first to force the rebuild */
9136 partition_sched_domains(0, NULL
, NULL
);
9138 rebuild_sched_domains();
9142 static ssize_t
sched_power_savings_store(const char *buf
, size_t count
, int smt
)
9144 unsigned int level
= 0;
9146 if (sscanf(buf
, "%u", &level
) != 1)
9150 * level is always be positive so don't check for
9151 * level < POWERSAVINGS_BALANCE_NONE which is 0
9152 * What happens on 0 or 1 byte write,
9153 * need to check for count as well?
9156 if (level
>= MAX_POWERSAVINGS_BALANCE_LEVELS
)
9160 sched_smt_power_savings
= level
;
9162 sched_mc_power_savings
= level
;
9164 arch_reinit_sched_domains();
9169 #ifdef CONFIG_SCHED_MC
9170 static ssize_t
sched_mc_power_savings_show(struct sysdev_class
*class,
9173 return sprintf(page
, "%u\n", sched_mc_power_savings
);
9175 static ssize_t
sched_mc_power_savings_store(struct sysdev_class
*class,
9176 const char *buf
, size_t count
)
9178 return sched_power_savings_store(buf
, count
, 0);
9180 static SYSDEV_CLASS_ATTR(sched_mc_power_savings
, 0644,
9181 sched_mc_power_savings_show
,
9182 sched_mc_power_savings_store
);
9185 #ifdef CONFIG_SCHED_SMT
9186 static ssize_t
sched_smt_power_savings_show(struct sysdev_class
*dev
,
9189 return sprintf(page
, "%u\n", sched_smt_power_savings
);
9191 static ssize_t
sched_smt_power_savings_store(struct sysdev_class
*dev
,
9192 const char *buf
, size_t count
)
9194 return sched_power_savings_store(buf
, count
, 1);
9196 static SYSDEV_CLASS_ATTR(sched_smt_power_savings
, 0644,
9197 sched_smt_power_savings_show
,
9198 sched_smt_power_savings_store
);
9201 int __init
sched_create_sysfs_power_savings_entries(struct sysdev_class
*cls
)
9205 #ifdef CONFIG_SCHED_SMT
9207 err
= sysfs_create_file(&cls
->kset
.kobj
,
9208 &attr_sched_smt_power_savings
.attr
);
9210 #ifdef CONFIG_SCHED_MC
9211 if (!err
&& mc_capable())
9212 err
= sysfs_create_file(&cls
->kset
.kobj
,
9213 &attr_sched_mc_power_savings
.attr
);
9217 #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
9219 #ifndef CONFIG_CPUSETS
9221 * Add online and remove offline CPUs from the scheduler domains.
9222 * When cpusets are enabled they take over this function.
9224 static int update_sched_domains(struct notifier_block
*nfb
,
9225 unsigned long action
, void *hcpu
)
9229 case CPU_ONLINE_FROZEN
:
9230 case CPU_DOWN_PREPARE
:
9231 case CPU_DOWN_PREPARE_FROZEN
:
9232 case CPU_DOWN_FAILED
:
9233 case CPU_DOWN_FAILED_FROZEN
:
9234 partition_sched_domains(1, NULL
, NULL
);
9243 static int update_runtime(struct notifier_block
*nfb
,
9244 unsigned long action
, void *hcpu
)
9246 int cpu
= (int)(long)hcpu
;
9249 case CPU_DOWN_PREPARE
:
9250 case CPU_DOWN_PREPARE_FROZEN
:
9251 disable_runtime(cpu_rq(cpu
));
9254 case CPU_DOWN_FAILED
:
9255 case CPU_DOWN_FAILED_FROZEN
:
9257 case CPU_ONLINE_FROZEN
:
9258 enable_runtime(cpu_rq(cpu
));
9266 void __init
sched_init_smp(void)
9268 cpumask_var_t non_isolated_cpus
;
9270 alloc_cpumask_var(&non_isolated_cpus
, GFP_KERNEL
);
9271 alloc_cpumask_var(&fallback_doms
, GFP_KERNEL
);
9273 #if defined(CONFIG_NUMA)
9274 sched_group_nodes_bycpu
= kzalloc(nr_cpu_ids
* sizeof(void **),
9276 BUG_ON(sched_group_nodes_bycpu
== NULL
);
9279 mutex_lock(&sched_domains_mutex
);
9280 arch_init_sched_domains(cpu_active_mask
);
9281 cpumask_andnot(non_isolated_cpus
, cpu_possible_mask
, cpu_isolated_map
);
9282 if (cpumask_empty(non_isolated_cpus
))
9283 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus
);
9284 mutex_unlock(&sched_domains_mutex
);
9287 #ifndef CONFIG_CPUSETS
9288 /* XXX: Theoretical race here - CPU may be hotplugged now */
9289 hotcpu_notifier(update_sched_domains
, 0);
9292 /* RT runtime code needs to handle some hotplug events */
9293 hotcpu_notifier(update_runtime
, 0);
9297 /* Move init over to a non-isolated CPU */
9298 if (set_cpus_allowed_ptr(current
, non_isolated_cpus
) < 0)
9300 sched_init_granularity();
9301 free_cpumask_var(non_isolated_cpus
);
9303 init_sched_rt_class();
9306 void __init
sched_init_smp(void)
9308 sched_init_granularity();
9310 #endif /* CONFIG_SMP */
9312 const_debug
unsigned int sysctl_timer_migration
= 1;
9314 int in_sched_functions(unsigned long addr
)
9316 return in_lock_functions(addr
) ||
9317 (addr
>= (unsigned long)__sched_text_start
9318 && addr
< (unsigned long)__sched_text_end
);
9321 static void init_cfs_rq(struct cfs_rq
*cfs_rq
, struct rq
*rq
)
9323 cfs_rq
->tasks_timeline
= RB_ROOT
;
9324 INIT_LIST_HEAD(&cfs_rq
->tasks
);
9325 #ifdef CONFIG_FAIR_GROUP_SCHED
9328 cfs_rq
->min_vruntime
= (u64
)(-(1LL << 20));
9331 static void init_rt_rq(struct rt_rq
*rt_rq
, struct rq
*rq
)
9333 struct rt_prio_array
*array
;
9336 array
= &rt_rq
->active
;
9337 for (i
= 0; i
< MAX_RT_PRIO
; i
++) {
9338 INIT_LIST_HEAD(array
->queue
+ i
);
9339 __clear_bit(i
, array
->bitmap
);
9341 /* delimiter for bitsearch: */
9342 __set_bit(MAX_RT_PRIO
, array
->bitmap
);
9344 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
9345 rt_rq
->highest_prio
.curr
= MAX_RT_PRIO
;
9347 rt_rq
->highest_prio
.next
= MAX_RT_PRIO
;
9351 rt_rq
->rt_nr_migratory
= 0;
9352 rt_rq
->overloaded
= 0;
9353 plist_head_init_raw(&rt_rq
->pushable_tasks
, &rq
->lock
);
9357 rt_rq
->rt_throttled
= 0;
9358 rt_rq
->rt_runtime
= 0;
9359 raw_spin_lock_init(&rt_rq
->rt_runtime_lock
);
9361 #ifdef CONFIG_RT_GROUP_SCHED
9362 rt_rq
->rt_nr_boosted
= 0;
9367 #ifdef CONFIG_FAIR_GROUP_SCHED
9368 static void init_tg_cfs_entry(struct task_group
*tg
, struct cfs_rq
*cfs_rq
,
9369 struct sched_entity
*se
, int cpu
, int add
,
9370 struct sched_entity
*parent
)
9372 struct rq
*rq
= cpu_rq(cpu
);
9373 tg
->cfs_rq
[cpu
] = cfs_rq
;
9374 init_cfs_rq(cfs_rq
, rq
);
9377 list_add(&cfs_rq
->leaf_cfs_rq_list
, &rq
->leaf_cfs_rq_list
);
9380 /* se could be NULL for init_task_group */
9385 se
->cfs_rq
= &rq
->cfs
;
9387 se
->cfs_rq
= parent
->my_q
;
9390 se
->load
.weight
= tg
->shares
;
9391 se
->load
.inv_weight
= 0;
9392 se
->parent
= parent
;
9396 #ifdef CONFIG_RT_GROUP_SCHED
9397 static void init_tg_rt_entry(struct task_group
*tg
, struct rt_rq
*rt_rq
,
9398 struct sched_rt_entity
*rt_se
, int cpu
, int add
,
9399 struct sched_rt_entity
*parent
)
9401 struct rq
*rq
= cpu_rq(cpu
);
9403 tg
->rt_rq
[cpu
] = rt_rq
;
9404 init_rt_rq(rt_rq
, rq
);
9406 rt_rq
->rt_se
= rt_se
;
9407 rt_rq
->rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
9409 list_add(&rt_rq
->leaf_rt_rq_list
, &rq
->leaf_rt_rq_list
);
9411 tg
->rt_se
[cpu
] = rt_se
;
9416 rt_se
->rt_rq
= &rq
->rt
;
9418 rt_se
->rt_rq
= parent
->my_q
;
9420 rt_se
->my_q
= rt_rq
;
9421 rt_se
->parent
= parent
;
9422 INIT_LIST_HEAD(&rt_se
->run_list
);
9426 void __init
sched_init(void)
9429 unsigned long alloc_size
= 0, ptr
;
9431 #ifdef CONFIG_FAIR_GROUP_SCHED
9432 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
9434 #ifdef CONFIG_RT_GROUP_SCHED
9435 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
9437 #ifdef CONFIG_USER_SCHED
9440 #ifdef CONFIG_CPUMASK_OFFSTACK
9441 alloc_size
+= num_possible_cpus() * cpumask_size();
9444 ptr
= (unsigned long)kzalloc(alloc_size
, GFP_NOWAIT
);
9446 #ifdef CONFIG_FAIR_GROUP_SCHED
9447 init_task_group
.se
= (struct sched_entity
**)ptr
;
9448 ptr
+= nr_cpu_ids
* sizeof(void **);
9450 init_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
9451 ptr
+= nr_cpu_ids
* sizeof(void **);
9453 #ifdef CONFIG_USER_SCHED
9454 root_task_group
.se
= (struct sched_entity
**)ptr
;
9455 ptr
+= nr_cpu_ids
* sizeof(void **);
9457 root_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
9458 ptr
+= nr_cpu_ids
* sizeof(void **);
9459 #endif /* CONFIG_USER_SCHED */
9460 #endif /* CONFIG_FAIR_GROUP_SCHED */
9461 #ifdef CONFIG_RT_GROUP_SCHED
9462 init_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
9463 ptr
+= nr_cpu_ids
* sizeof(void **);
9465 init_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
9466 ptr
+= nr_cpu_ids
* sizeof(void **);
9468 #ifdef CONFIG_USER_SCHED
9469 root_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
9470 ptr
+= nr_cpu_ids
* sizeof(void **);
9472 root_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
9473 ptr
+= nr_cpu_ids
* sizeof(void **);
9474 #endif /* CONFIG_USER_SCHED */
9475 #endif /* CONFIG_RT_GROUP_SCHED */
9476 #ifdef CONFIG_CPUMASK_OFFSTACK
9477 for_each_possible_cpu(i
) {
9478 per_cpu(load_balance_tmpmask
, i
) = (void *)ptr
;
9479 ptr
+= cpumask_size();
9481 #endif /* CONFIG_CPUMASK_OFFSTACK */
9485 init_defrootdomain();
9488 init_rt_bandwidth(&def_rt_bandwidth
,
9489 global_rt_period(), global_rt_runtime());
9491 #ifdef CONFIG_RT_GROUP_SCHED
9492 init_rt_bandwidth(&init_task_group
.rt_bandwidth
,
9493 global_rt_period(), global_rt_runtime());
9494 #ifdef CONFIG_USER_SCHED
9495 init_rt_bandwidth(&root_task_group
.rt_bandwidth
,
9496 global_rt_period(), RUNTIME_INF
);
9497 #endif /* CONFIG_USER_SCHED */
9498 #endif /* CONFIG_RT_GROUP_SCHED */
9500 #ifdef CONFIG_GROUP_SCHED
9501 list_add(&init_task_group
.list
, &task_groups
);
9502 INIT_LIST_HEAD(&init_task_group
.children
);
9504 #ifdef CONFIG_USER_SCHED
9505 INIT_LIST_HEAD(&root_task_group
.children
);
9506 init_task_group
.parent
= &root_task_group
;
9507 list_add(&init_task_group
.siblings
, &root_task_group
.children
);
9508 #endif /* CONFIG_USER_SCHED */
9509 #endif /* CONFIG_GROUP_SCHED */
9511 #if defined CONFIG_FAIR_GROUP_SCHED && defined CONFIG_SMP
9512 update_shares_data
= __alloc_percpu(nr_cpu_ids
* sizeof(unsigned long),
9513 __alignof__(unsigned long));
9515 for_each_possible_cpu(i
) {
9519 raw_spin_lock_init(&rq
->lock
);
9521 rq
->calc_load_active
= 0;
9522 rq
->calc_load_update
= jiffies
+ LOAD_FREQ
;
9523 init_cfs_rq(&rq
->cfs
, rq
);
9524 init_rt_rq(&rq
->rt
, rq
);
9525 #ifdef CONFIG_FAIR_GROUP_SCHED
9526 init_task_group
.shares
= init_task_group_load
;
9527 INIT_LIST_HEAD(&rq
->leaf_cfs_rq_list
);
9528 #ifdef CONFIG_CGROUP_SCHED
9530 * How much cpu bandwidth does init_task_group get?
9532 * In case of task-groups formed thr' the cgroup filesystem, it
9533 * gets 100% of the cpu resources in the system. This overall
9534 * system cpu resource is divided among the tasks of
9535 * init_task_group and its child task-groups in a fair manner,
9536 * based on each entity's (task or task-group's) weight
9537 * (se->load.weight).
9539 * In other words, if init_task_group has 10 tasks of weight
9540 * 1024) and two child groups A0 and A1 (of weight 1024 each),
9541 * then A0's share of the cpu resource is:
9543 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
9545 * We achieve this by letting init_task_group's tasks sit
9546 * directly in rq->cfs (i.e init_task_group->se[] = NULL).
9548 init_tg_cfs_entry(&init_task_group
, &rq
->cfs
, NULL
, i
, 1, NULL
);
9549 #elif defined CONFIG_USER_SCHED
9550 root_task_group
.shares
= NICE_0_LOAD
;
9551 init_tg_cfs_entry(&root_task_group
, &rq
->cfs
, NULL
, i
, 0, NULL
);
9553 * In case of task-groups formed thr' the user id of tasks,
9554 * init_task_group represents tasks belonging to root user.
9555 * Hence it forms a sibling of all subsequent groups formed.
9556 * In this case, init_task_group gets only a fraction of overall
9557 * system cpu resource, based on the weight assigned to root
9558 * user's cpu share (INIT_TASK_GROUP_LOAD). This is accomplished
9559 * by letting tasks of init_task_group sit in a separate cfs_rq
9560 * (init_tg_cfs_rq) and having one entity represent this group of
9561 * tasks in rq->cfs (i.e init_task_group->se[] != NULL).
9563 init_tg_cfs_entry(&init_task_group
,
9564 &per_cpu(init_tg_cfs_rq
, i
),
9565 &per_cpu(init_sched_entity
, i
), i
, 1,
9566 root_task_group
.se
[i
]);
9569 #endif /* CONFIG_FAIR_GROUP_SCHED */
9571 rq
->rt
.rt_runtime
= def_rt_bandwidth
.rt_runtime
;
9572 #ifdef CONFIG_RT_GROUP_SCHED
9573 INIT_LIST_HEAD(&rq
->leaf_rt_rq_list
);
9574 #ifdef CONFIG_CGROUP_SCHED
9575 init_tg_rt_entry(&init_task_group
, &rq
->rt
, NULL
, i
, 1, NULL
);
9576 #elif defined CONFIG_USER_SCHED
9577 init_tg_rt_entry(&root_task_group
, &rq
->rt
, NULL
, i
, 0, NULL
);
9578 init_tg_rt_entry(&init_task_group
,
9579 &per_cpu(init_rt_rq_var
, i
),
9580 &per_cpu(init_sched_rt_entity
, i
), i
, 1,
9581 root_task_group
.rt_se
[i
]);
9585 for (j
= 0; j
< CPU_LOAD_IDX_MAX
; j
++)
9586 rq
->cpu_load
[j
] = 0;
9590 rq
->post_schedule
= 0;
9591 rq
->active_balance
= 0;
9592 rq
->next_balance
= jiffies
;
9596 rq
->migration_thread
= NULL
;
9598 rq
->avg_idle
= 2*sysctl_sched_migration_cost
;
9599 INIT_LIST_HEAD(&rq
->migration_queue
);
9600 rq_attach_root(rq
, &def_root_domain
);
9603 atomic_set(&rq
->nr_iowait
, 0);
9606 set_load_weight(&init_task
);
9608 #ifdef CONFIG_PREEMPT_NOTIFIERS
9609 INIT_HLIST_HEAD(&init_task
.preempt_notifiers
);
9613 open_softirq(SCHED_SOFTIRQ
, run_rebalance_domains
);
9616 #ifdef CONFIG_RT_MUTEXES
9617 plist_head_init_raw(&init_task
.pi_waiters
, &init_task
.pi_lock
);
9621 * The boot idle thread does lazy MMU switching as well:
9623 atomic_inc(&init_mm
.mm_count
);
9624 enter_lazy_tlb(&init_mm
, current
);
9627 * Make us the idle thread. Technically, schedule() should not be
9628 * called from this thread, however somewhere below it might be,
9629 * but because we are the idle thread, we just pick up running again
9630 * when this runqueue becomes "idle".
9632 init_idle(current
, smp_processor_id());
9634 calc_load_update
= jiffies
+ LOAD_FREQ
;
9637 * During early bootup we pretend to be a normal task:
9639 current
->sched_class
= &fair_sched_class
;
9641 /* Allocate the nohz_cpu_mask if CONFIG_CPUMASK_OFFSTACK */
9642 zalloc_cpumask_var(&nohz_cpu_mask
, GFP_NOWAIT
);
9645 zalloc_cpumask_var(&nohz
.cpu_mask
, GFP_NOWAIT
);
9646 alloc_cpumask_var(&nohz
.ilb_grp_nohz_mask
, GFP_NOWAIT
);
9648 /* May be allocated at isolcpus cmdline parse time */
9649 if (cpu_isolated_map
== NULL
)
9650 zalloc_cpumask_var(&cpu_isolated_map
, GFP_NOWAIT
);
9655 scheduler_running
= 1;
9658 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
9659 static inline int preempt_count_equals(int preempt_offset
)
9661 int nested
= preempt_count() & ~PREEMPT_ACTIVE
;
9663 return (nested
== PREEMPT_INATOMIC_BASE
+ preempt_offset
);
9666 void __might_sleep(char *file
, int line
, int preempt_offset
)
9669 static unsigned long prev_jiffy
; /* ratelimiting */
9671 if ((preempt_count_equals(preempt_offset
) && !irqs_disabled()) ||
9672 system_state
!= SYSTEM_RUNNING
|| oops_in_progress
)
9674 if (time_before(jiffies
, prev_jiffy
+ HZ
) && prev_jiffy
)
9676 prev_jiffy
= jiffies
;
9678 pr_err("BUG: sleeping function called from invalid context at %s:%d\n",
9680 pr_err("in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
9681 in_atomic(), irqs_disabled(),
9682 current
->pid
, current
->comm
);
9684 debug_show_held_locks(current
);
9685 if (irqs_disabled())
9686 print_irqtrace_events(current
);
9690 EXPORT_SYMBOL(__might_sleep
);
9693 #ifdef CONFIG_MAGIC_SYSRQ
9694 static void normalize_task(struct rq
*rq
, struct task_struct
*p
)
9698 update_rq_clock(rq
);
9699 on_rq
= p
->se
.on_rq
;
9701 deactivate_task(rq
, p
, 0);
9702 __setscheduler(rq
, p
, SCHED_NORMAL
, 0);
9704 activate_task(rq
, p
, 0);
9705 resched_task(rq
->curr
);
9709 void normalize_rt_tasks(void)
9711 struct task_struct
*g
, *p
;
9712 unsigned long flags
;
9715 read_lock_irqsave(&tasklist_lock
, flags
);
9716 do_each_thread(g
, p
) {
9718 * Only normalize user tasks:
9723 p
->se
.exec_start
= 0;
9724 #ifdef CONFIG_SCHEDSTATS
9725 p
->se
.wait_start
= 0;
9726 p
->se
.sleep_start
= 0;
9727 p
->se
.block_start
= 0;
9732 * Renice negative nice level userspace
9735 if (TASK_NICE(p
) < 0 && p
->mm
)
9736 set_user_nice(p
, 0);
9740 raw_spin_lock(&p
->pi_lock
);
9741 rq
= __task_rq_lock(p
);
9743 normalize_task(rq
, p
);
9745 __task_rq_unlock(rq
);
9746 raw_spin_unlock(&p
->pi_lock
);
9747 } while_each_thread(g
, p
);
9749 read_unlock_irqrestore(&tasklist_lock
, flags
);
9752 #endif /* CONFIG_MAGIC_SYSRQ */
9756 * These functions are only useful for the IA64 MCA handling.
9758 * They can only be called when the whole system has been
9759 * stopped - every CPU needs to be quiescent, and no scheduling
9760 * activity can take place. Using them for anything else would
9761 * be a serious bug, and as a result, they aren't even visible
9762 * under any other configuration.
9766 * curr_task - return the current task for a given cpu.
9767 * @cpu: the processor in question.
9769 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
9771 struct task_struct
*curr_task(int cpu
)
9773 return cpu_curr(cpu
);
9777 * set_curr_task - set the current task for a given cpu.
9778 * @cpu: the processor in question.
9779 * @p: the task pointer to set.
9781 * Description: This function must only be used when non-maskable interrupts
9782 * are serviced on a separate stack. It allows the architecture to switch the
9783 * notion of the current task on a cpu in a non-blocking manner. This function
9784 * must be called with all CPU's synchronized, and interrupts disabled, the
9785 * and caller must save the original value of the current task (see
9786 * curr_task() above) and restore that value before reenabling interrupts and
9787 * re-starting the system.
9789 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
9791 void set_curr_task(int cpu
, struct task_struct
*p
)
9798 #ifdef CONFIG_FAIR_GROUP_SCHED
9799 static void free_fair_sched_group(struct task_group
*tg
)
9803 for_each_possible_cpu(i
) {
9805 kfree(tg
->cfs_rq
[i
]);
9815 int alloc_fair_sched_group(struct task_group
*tg
, struct task_group
*parent
)
9817 struct cfs_rq
*cfs_rq
;
9818 struct sched_entity
*se
;
9822 tg
->cfs_rq
= kzalloc(sizeof(cfs_rq
) * nr_cpu_ids
, GFP_KERNEL
);
9825 tg
->se
= kzalloc(sizeof(se
) * nr_cpu_ids
, GFP_KERNEL
);
9829 tg
->shares
= NICE_0_LOAD
;
9831 for_each_possible_cpu(i
) {
9834 cfs_rq
= kzalloc_node(sizeof(struct cfs_rq
),
9835 GFP_KERNEL
, cpu_to_node(i
));
9839 se
= kzalloc_node(sizeof(struct sched_entity
),
9840 GFP_KERNEL
, cpu_to_node(i
));
9844 init_tg_cfs_entry(tg
, cfs_rq
, se
, i
, 0, parent
->se
[i
]);
9855 static inline void register_fair_sched_group(struct task_group
*tg
, int cpu
)
9857 list_add_rcu(&tg
->cfs_rq
[cpu
]->leaf_cfs_rq_list
,
9858 &cpu_rq(cpu
)->leaf_cfs_rq_list
);
9861 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
9863 list_del_rcu(&tg
->cfs_rq
[cpu
]->leaf_cfs_rq_list
);
9865 #else /* !CONFG_FAIR_GROUP_SCHED */
9866 static inline void free_fair_sched_group(struct task_group
*tg
)
9871 int alloc_fair_sched_group(struct task_group
*tg
, struct task_group
*parent
)
9876 static inline void register_fair_sched_group(struct task_group
*tg
, int cpu
)
9880 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
9883 #endif /* CONFIG_FAIR_GROUP_SCHED */
9885 #ifdef CONFIG_RT_GROUP_SCHED
9886 static void free_rt_sched_group(struct task_group
*tg
)
9890 destroy_rt_bandwidth(&tg
->rt_bandwidth
);
9892 for_each_possible_cpu(i
) {
9894 kfree(tg
->rt_rq
[i
]);
9896 kfree(tg
->rt_se
[i
]);
9904 int alloc_rt_sched_group(struct task_group
*tg
, struct task_group
*parent
)
9906 struct rt_rq
*rt_rq
;
9907 struct sched_rt_entity
*rt_se
;
9911 tg
->rt_rq
= kzalloc(sizeof(rt_rq
) * nr_cpu_ids
, GFP_KERNEL
);
9914 tg
->rt_se
= kzalloc(sizeof(rt_se
) * nr_cpu_ids
, GFP_KERNEL
);
9918 init_rt_bandwidth(&tg
->rt_bandwidth
,
9919 ktime_to_ns(def_rt_bandwidth
.rt_period
), 0);
9921 for_each_possible_cpu(i
) {
9924 rt_rq
= kzalloc_node(sizeof(struct rt_rq
),
9925 GFP_KERNEL
, cpu_to_node(i
));
9929 rt_se
= kzalloc_node(sizeof(struct sched_rt_entity
),
9930 GFP_KERNEL
, cpu_to_node(i
));
9934 init_tg_rt_entry(tg
, rt_rq
, rt_se
, i
, 0, parent
->rt_se
[i
]);
9945 static inline void register_rt_sched_group(struct task_group
*tg
, int cpu
)
9947 list_add_rcu(&tg
->rt_rq
[cpu
]->leaf_rt_rq_list
,
9948 &cpu_rq(cpu
)->leaf_rt_rq_list
);
9951 static inline void unregister_rt_sched_group(struct task_group
*tg
, int cpu
)
9953 list_del_rcu(&tg
->rt_rq
[cpu
]->leaf_rt_rq_list
);
9955 #else /* !CONFIG_RT_GROUP_SCHED */
9956 static inline void free_rt_sched_group(struct task_group
*tg
)
9961 int alloc_rt_sched_group(struct task_group
*tg
, struct task_group
*parent
)
9966 static inline void register_rt_sched_group(struct task_group
*tg
, int cpu
)
9970 static inline void unregister_rt_sched_group(struct task_group
*tg
, int cpu
)
9973 #endif /* CONFIG_RT_GROUP_SCHED */
9975 #ifdef CONFIG_GROUP_SCHED
9976 static void free_sched_group(struct task_group
*tg
)
9978 free_fair_sched_group(tg
);
9979 free_rt_sched_group(tg
);
9983 /* allocate runqueue etc for a new task group */
9984 struct task_group
*sched_create_group(struct task_group
*parent
)
9986 struct task_group
*tg
;
9987 unsigned long flags
;
9990 tg
= kzalloc(sizeof(*tg
), GFP_KERNEL
);
9992 return ERR_PTR(-ENOMEM
);
9994 if (!alloc_fair_sched_group(tg
, parent
))
9997 if (!alloc_rt_sched_group(tg
, parent
))
10000 spin_lock_irqsave(&task_group_lock
, flags
);
10001 for_each_possible_cpu(i
) {
10002 register_fair_sched_group(tg
, i
);
10003 register_rt_sched_group(tg
, i
);
10005 list_add_rcu(&tg
->list
, &task_groups
);
10007 WARN_ON(!parent
); /* root should already exist */
10009 tg
->parent
= parent
;
10010 INIT_LIST_HEAD(&tg
->children
);
10011 list_add_rcu(&tg
->siblings
, &parent
->children
);
10012 spin_unlock_irqrestore(&task_group_lock
, flags
);
10017 free_sched_group(tg
);
10018 return ERR_PTR(-ENOMEM
);
10021 /* rcu callback to free various structures associated with a task group */
10022 static void free_sched_group_rcu(struct rcu_head
*rhp
)
10024 /* now it should be safe to free those cfs_rqs */
10025 free_sched_group(container_of(rhp
, struct task_group
, rcu
));
10028 /* Destroy runqueue etc associated with a task group */
10029 void sched_destroy_group(struct task_group
*tg
)
10031 unsigned long flags
;
10034 spin_lock_irqsave(&task_group_lock
, flags
);
10035 for_each_possible_cpu(i
) {
10036 unregister_fair_sched_group(tg
, i
);
10037 unregister_rt_sched_group(tg
, i
);
10039 list_del_rcu(&tg
->list
);
10040 list_del_rcu(&tg
->siblings
);
10041 spin_unlock_irqrestore(&task_group_lock
, flags
);
10043 /* wait for possible concurrent references to cfs_rqs complete */
10044 call_rcu(&tg
->rcu
, free_sched_group_rcu
);
10047 /* change task's runqueue when it moves between groups.
10048 * The caller of this function should have put the task in its new group
10049 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
10050 * reflect its new group.
10052 void sched_move_task(struct task_struct
*tsk
)
10054 int on_rq
, running
;
10055 unsigned long flags
;
10058 rq
= task_rq_lock(tsk
, &flags
);
10060 update_rq_clock(rq
);
10062 running
= task_current(rq
, tsk
);
10063 on_rq
= tsk
->se
.on_rq
;
10066 dequeue_task(rq
, tsk
, 0);
10067 if (unlikely(running
))
10068 tsk
->sched_class
->put_prev_task(rq
, tsk
);
10070 set_task_rq(tsk
, task_cpu(tsk
));
10072 #ifdef CONFIG_FAIR_GROUP_SCHED
10073 if (tsk
->sched_class
->moved_group
)
10074 tsk
->sched_class
->moved_group(tsk
);
10077 if (unlikely(running
))
10078 tsk
->sched_class
->set_curr_task(rq
);
10080 enqueue_task(rq
, tsk
, 0);
10082 task_rq_unlock(rq
, &flags
);
10084 #endif /* CONFIG_GROUP_SCHED */
10086 #ifdef CONFIG_FAIR_GROUP_SCHED
10087 static void __set_se_shares(struct sched_entity
*se
, unsigned long shares
)
10089 struct cfs_rq
*cfs_rq
= se
->cfs_rq
;
10094 dequeue_entity(cfs_rq
, se
, 0);
10096 se
->load
.weight
= shares
;
10097 se
->load
.inv_weight
= 0;
10100 enqueue_entity(cfs_rq
, se
, 0);
10103 static void set_se_shares(struct sched_entity
*se
, unsigned long shares
)
10105 struct cfs_rq
*cfs_rq
= se
->cfs_rq
;
10106 struct rq
*rq
= cfs_rq
->rq
;
10107 unsigned long flags
;
10109 raw_spin_lock_irqsave(&rq
->lock
, flags
);
10110 __set_se_shares(se
, shares
);
10111 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
10114 static DEFINE_MUTEX(shares_mutex
);
10116 int sched_group_set_shares(struct task_group
*tg
, unsigned long shares
)
10119 unsigned long flags
;
10122 * We can't change the weight of the root cgroup.
10127 if (shares
< MIN_SHARES
)
10128 shares
= MIN_SHARES
;
10129 else if (shares
> MAX_SHARES
)
10130 shares
= MAX_SHARES
;
10132 mutex_lock(&shares_mutex
);
10133 if (tg
->shares
== shares
)
10136 spin_lock_irqsave(&task_group_lock
, flags
);
10137 for_each_possible_cpu(i
)
10138 unregister_fair_sched_group(tg
, i
);
10139 list_del_rcu(&tg
->siblings
);
10140 spin_unlock_irqrestore(&task_group_lock
, flags
);
10142 /* wait for any ongoing reference to this group to finish */
10143 synchronize_sched();
10146 * Now we are free to modify the group's share on each cpu
10147 * w/o tripping rebalance_share or load_balance_fair.
10149 tg
->shares
= shares
;
10150 for_each_possible_cpu(i
) {
10152 * force a rebalance
10154 cfs_rq_set_shares(tg
->cfs_rq
[i
], 0);
10155 set_se_shares(tg
->se
[i
], shares
);
10159 * Enable load balance activity on this group, by inserting it back on
10160 * each cpu's rq->leaf_cfs_rq_list.
10162 spin_lock_irqsave(&task_group_lock
, flags
);
10163 for_each_possible_cpu(i
)
10164 register_fair_sched_group(tg
, i
);
10165 list_add_rcu(&tg
->siblings
, &tg
->parent
->children
);
10166 spin_unlock_irqrestore(&task_group_lock
, flags
);
10168 mutex_unlock(&shares_mutex
);
10172 unsigned long sched_group_shares(struct task_group
*tg
)
10178 #ifdef CONFIG_RT_GROUP_SCHED
10180 * Ensure that the real time constraints are schedulable.
10182 static DEFINE_MUTEX(rt_constraints_mutex
);
10184 static unsigned long to_ratio(u64 period
, u64 runtime
)
10186 if (runtime
== RUNTIME_INF
)
10189 return div64_u64(runtime
<< 20, period
);
10192 /* Must be called with tasklist_lock held */
10193 static inline int tg_has_rt_tasks(struct task_group
*tg
)
10195 struct task_struct
*g
, *p
;
10197 do_each_thread(g
, p
) {
10198 if (rt_task(p
) && rt_rq_of_se(&p
->rt
)->tg
== tg
)
10200 } while_each_thread(g
, p
);
10205 struct rt_schedulable_data
{
10206 struct task_group
*tg
;
10211 static int tg_schedulable(struct task_group
*tg
, void *data
)
10213 struct rt_schedulable_data
*d
= data
;
10214 struct task_group
*child
;
10215 unsigned long total
, sum
= 0;
10216 u64 period
, runtime
;
10218 period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
10219 runtime
= tg
->rt_bandwidth
.rt_runtime
;
10222 period
= d
->rt_period
;
10223 runtime
= d
->rt_runtime
;
10226 #ifdef CONFIG_USER_SCHED
10227 if (tg
== &root_task_group
) {
10228 period
= global_rt_period();
10229 runtime
= global_rt_runtime();
10234 * Cannot have more runtime than the period.
10236 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
10240 * Ensure we don't starve existing RT tasks.
10242 if (rt_bandwidth_enabled() && !runtime
&& tg_has_rt_tasks(tg
))
10245 total
= to_ratio(period
, runtime
);
10248 * Nobody can have more than the global setting allows.
10250 if (total
> to_ratio(global_rt_period(), global_rt_runtime()))
10254 * The sum of our children's runtime should not exceed our own.
10256 list_for_each_entry_rcu(child
, &tg
->children
, siblings
) {
10257 period
= ktime_to_ns(child
->rt_bandwidth
.rt_period
);
10258 runtime
= child
->rt_bandwidth
.rt_runtime
;
10260 if (child
== d
->tg
) {
10261 period
= d
->rt_period
;
10262 runtime
= d
->rt_runtime
;
10265 sum
+= to_ratio(period
, runtime
);
10274 static int __rt_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
)
10276 struct rt_schedulable_data data
= {
10278 .rt_period
= period
,
10279 .rt_runtime
= runtime
,
10282 return walk_tg_tree(tg_schedulable
, tg_nop
, &data
);
10285 static int tg_set_bandwidth(struct task_group
*tg
,
10286 u64 rt_period
, u64 rt_runtime
)
10290 mutex_lock(&rt_constraints_mutex
);
10291 read_lock(&tasklist_lock
);
10292 err
= __rt_schedulable(tg
, rt_period
, rt_runtime
);
10296 raw_spin_lock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
10297 tg
->rt_bandwidth
.rt_period
= ns_to_ktime(rt_period
);
10298 tg
->rt_bandwidth
.rt_runtime
= rt_runtime
;
10300 for_each_possible_cpu(i
) {
10301 struct rt_rq
*rt_rq
= tg
->rt_rq
[i
];
10303 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
10304 rt_rq
->rt_runtime
= rt_runtime
;
10305 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
10307 raw_spin_unlock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
10309 read_unlock(&tasklist_lock
);
10310 mutex_unlock(&rt_constraints_mutex
);
10315 int sched_group_set_rt_runtime(struct task_group
*tg
, long rt_runtime_us
)
10317 u64 rt_runtime
, rt_period
;
10319 rt_period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
10320 rt_runtime
= (u64
)rt_runtime_us
* NSEC_PER_USEC
;
10321 if (rt_runtime_us
< 0)
10322 rt_runtime
= RUNTIME_INF
;
10324 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
10327 long sched_group_rt_runtime(struct task_group
*tg
)
10331 if (tg
->rt_bandwidth
.rt_runtime
== RUNTIME_INF
)
10334 rt_runtime_us
= tg
->rt_bandwidth
.rt_runtime
;
10335 do_div(rt_runtime_us
, NSEC_PER_USEC
);
10336 return rt_runtime_us
;
10339 int sched_group_set_rt_period(struct task_group
*tg
, long rt_period_us
)
10341 u64 rt_runtime
, rt_period
;
10343 rt_period
= (u64
)rt_period_us
* NSEC_PER_USEC
;
10344 rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
10346 if (rt_period
== 0)
10349 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
10352 long sched_group_rt_period(struct task_group
*tg
)
10356 rt_period_us
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
10357 do_div(rt_period_us
, NSEC_PER_USEC
);
10358 return rt_period_us
;
10361 static int sched_rt_global_constraints(void)
10363 u64 runtime
, period
;
10366 if (sysctl_sched_rt_period
<= 0)
10369 runtime
= global_rt_runtime();
10370 period
= global_rt_period();
10373 * Sanity check on the sysctl variables.
10375 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
10378 mutex_lock(&rt_constraints_mutex
);
10379 read_lock(&tasklist_lock
);
10380 ret
= __rt_schedulable(NULL
, 0, 0);
10381 read_unlock(&tasklist_lock
);
10382 mutex_unlock(&rt_constraints_mutex
);
10387 int sched_rt_can_attach(struct task_group
*tg
, struct task_struct
*tsk
)
10389 /* Don't accept realtime tasks when there is no way for them to run */
10390 if (rt_task(tsk
) && tg
->rt_bandwidth
.rt_runtime
== 0)
10396 #else /* !CONFIG_RT_GROUP_SCHED */
10397 static int sched_rt_global_constraints(void)
10399 unsigned long flags
;
10402 if (sysctl_sched_rt_period
<= 0)
10406 * There's always some RT tasks in the root group
10407 * -- migration, kstopmachine etc..
10409 if (sysctl_sched_rt_runtime
== 0)
10412 raw_spin_lock_irqsave(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
10413 for_each_possible_cpu(i
) {
10414 struct rt_rq
*rt_rq
= &cpu_rq(i
)->rt
;
10416 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
10417 rt_rq
->rt_runtime
= global_rt_runtime();
10418 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
10420 raw_spin_unlock_irqrestore(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
10424 #endif /* CONFIG_RT_GROUP_SCHED */
10426 int sched_rt_handler(struct ctl_table
*table
, int write
,
10427 void __user
*buffer
, size_t *lenp
,
10431 int old_period
, old_runtime
;
10432 static DEFINE_MUTEX(mutex
);
10434 mutex_lock(&mutex
);
10435 old_period
= sysctl_sched_rt_period
;
10436 old_runtime
= sysctl_sched_rt_runtime
;
10438 ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
10440 if (!ret
&& write
) {
10441 ret
= sched_rt_global_constraints();
10443 sysctl_sched_rt_period
= old_period
;
10444 sysctl_sched_rt_runtime
= old_runtime
;
10446 def_rt_bandwidth
.rt_runtime
= global_rt_runtime();
10447 def_rt_bandwidth
.rt_period
=
10448 ns_to_ktime(global_rt_period());
10451 mutex_unlock(&mutex
);
10456 #ifdef CONFIG_CGROUP_SCHED
10458 /* return corresponding task_group object of a cgroup */
10459 static inline struct task_group
*cgroup_tg(struct cgroup
*cgrp
)
10461 return container_of(cgroup_subsys_state(cgrp
, cpu_cgroup_subsys_id
),
10462 struct task_group
, css
);
10465 static struct cgroup_subsys_state
*
10466 cpu_cgroup_create(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
10468 struct task_group
*tg
, *parent
;
10470 if (!cgrp
->parent
) {
10471 /* This is early initialization for the top cgroup */
10472 return &init_task_group
.css
;
10475 parent
= cgroup_tg(cgrp
->parent
);
10476 tg
= sched_create_group(parent
);
10478 return ERR_PTR(-ENOMEM
);
10484 cpu_cgroup_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
10486 struct task_group
*tg
= cgroup_tg(cgrp
);
10488 sched_destroy_group(tg
);
10492 cpu_cgroup_can_attach_task(struct cgroup
*cgrp
, struct task_struct
*tsk
)
10494 #ifdef CONFIG_RT_GROUP_SCHED
10495 if (!sched_rt_can_attach(cgroup_tg(cgrp
), tsk
))
10498 /* We don't support RT-tasks being in separate groups */
10499 if (tsk
->sched_class
!= &fair_sched_class
)
10506 cpu_cgroup_can_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
10507 struct task_struct
*tsk
, bool threadgroup
)
10509 int retval
= cpu_cgroup_can_attach_task(cgrp
, tsk
);
10513 struct task_struct
*c
;
10515 list_for_each_entry_rcu(c
, &tsk
->thread_group
, thread_group
) {
10516 retval
= cpu_cgroup_can_attach_task(cgrp
, c
);
10528 cpu_cgroup_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
10529 struct cgroup
*old_cont
, struct task_struct
*tsk
,
10532 sched_move_task(tsk
);
10534 struct task_struct
*c
;
10536 list_for_each_entry_rcu(c
, &tsk
->thread_group
, thread_group
) {
10537 sched_move_task(c
);
10543 #ifdef CONFIG_FAIR_GROUP_SCHED
10544 static int cpu_shares_write_u64(struct cgroup
*cgrp
, struct cftype
*cftype
,
10547 return sched_group_set_shares(cgroup_tg(cgrp
), shareval
);
10550 static u64
cpu_shares_read_u64(struct cgroup
*cgrp
, struct cftype
*cft
)
10552 struct task_group
*tg
= cgroup_tg(cgrp
);
10554 return (u64
) tg
->shares
;
10556 #endif /* CONFIG_FAIR_GROUP_SCHED */
10558 #ifdef CONFIG_RT_GROUP_SCHED
10559 static int cpu_rt_runtime_write(struct cgroup
*cgrp
, struct cftype
*cft
,
10562 return sched_group_set_rt_runtime(cgroup_tg(cgrp
), val
);
10565 static s64
cpu_rt_runtime_read(struct cgroup
*cgrp
, struct cftype
*cft
)
10567 return sched_group_rt_runtime(cgroup_tg(cgrp
));
10570 static int cpu_rt_period_write_uint(struct cgroup
*cgrp
, struct cftype
*cftype
,
10573 return sched_group_set_rt_period(cgroup_tg(cgrp
), rt_period_us
);
10576 static u64
cpu_rt_period_read_uint(struct cgroup
*cgrp
, struct cftype
*cft
)
10578 return sched_group_rt_period(cgroup_tg(cgrp
));
10580 #endif /* CONFIG_RT_GROUP_SCHED */
10582 static struct cftype cpu_files
[] = {
10583 #ifdef CONFIG_FAIR_GROUP_SCHED
10586 .read_u64
= cpu_shares_read_u64
,
10587 .write_u64
= cpu_shares_write_u64
,
10590 #ifdef CONFIG_RT_GROUP_SCHED
10592 .name
= "rt_runtime_us",
10593 .read_s64
= cpu_rt_runtime_read
,
10594 .write_s64
= cpu_rt_runtime_write
,
10597 .name
= "rt_period_us",
10598 .read_u64
= cpu_rt_period_read_uint
,
10599 .write_u64
= cpu_rt_period_write_uint
,
10604 static int cpu_cgroup_populate(struct cgroup_subsys
*ss
, struct cgroup
*cont
)
10606 return cgroup_add_files(cont
, ss
, cpu_files
, ARRAY_SIZE(cpu_files
));
10609 struct cgroup_subsys cpu_cgroup_subsys
= {
10611 .create
= cpu_cgroup_create
,
10612 .destroy
= cpu_cgroup_destroy
,
10613 .can_attach
= cpu_cgroup_can_attach
,
10614 .attach
= cpu_cgroup_attach
,
10615 .populate
= cpu_cgroup_populate
,
10616 .subsys_id
= cpu_cgroup_subsys_id
,
10620 #endif /* CONFIG_CGROUP_SCHED */
10622 #ifdef CONFIG_CGROUP_CPUACCT
10625 * CPU accounting code for task groups.
10627 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
10628 * (balbir@in.ibm.com).
10631 /* track cpu usage of a group of tasks and its child groups */
10633 struct cgroup_subsys_state css
;
10634 /* cpuusage holds pointer to a u64-type object on every cpu */
10636 struct percpu_counter cpustat
[CPUACCT_STAT_NSTATS
];
10637 struct cpuacct
*parent
;
10640 struct cgroup_subsys cpuacct_subsys
;
10642 /* return cpu accounting group corresponding to this container */
10643 static inline struct cpuacct
*cgroup_ca(struct cgroup
*cgrp
)
10645 return container_of(cgroup_subsys_state(cgrp
, cpuacct_subsys_id
),
10646 struct cpuacct
, css
);
10649 /* return cpu accounting group to which this task belongs */
10650 static inline struct cpuacct
*task_ca(struct task_struct
*tsk
)
10652 return container_of(task_subsys_state(tsk
, cpuacct_subsys_id
),
10653 struct cpuacct
, css
);
10656 /* create a new cpu accounting group */
10657 static struct cgroup_subsys_state
*cpuacct_create(
10658 struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
10660 struct cpuacct
*ca
= kzalloc(sizeof(*ca
), GFP_KERNEL
);
10666 ca
->cpuusage
= alloc_percpu(u64
);
10670 for (i
= 0; i
< CPUACCT_STAT_NSTATS
; i
++)
10671 if (percpu_counter_init(&ca
->cpustat
[i
], 0))
10672 goto out_free_counters
;
10675 ca
->parent
= cgroup_ca(cgrp
->parent
);
10681 percpu_counter_destroy(&ca
->cpustat
[i
]);
10682 free_percpu(ca
->cpuusage
);
10686 return ERR_PTR(-ENOMEM
);
10689 /* destroy an existing cpu accounting group */
10691 cpuacct_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
10693 struct cpuacct
*ca
= cgroup_ca(cgrp
);
10696 for (i
= 0; i
< CPUACCT_STAT_NSTATS
; i
++)
10697 percpu_counter_destroy(&ca
->cpustat
[i
]);
10698 free_percpu(ca
->cpuusage
);
10702 static u64
cpuacct_cpuusage_read(struct cpuacct
*ca
, int cpu
)
10704 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
10707 #ifndef CONFIG_64BIT
10709 * Take rq->lock to make 64-bit read safe on 32-bit platforms.
10711 raw_spin_lock_irq(&cpu_rq(cpu
)->lock
);
10713 raw_spin_unlock_irq(&cpu_rq(cpu
)->lock
);
10721 static void cpuacct_cpuusage_write(struct cpuacct
*ca
, int cpu
, u64 val
)
10723 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
10725 #ifndef CONFIG_64BIT
10727 * Take rq->lock to make 64-bit write safe on 32-bit platforms.
10729 raw_spin_lock_irq(&cpu_rq(cpu
)->lock
);
10731 raw_spin_unlock_irq(&cpu_rq(cpu
)->lock
);
10737 /* return total cpu usage (in nanoseconds) of a group */
10738 static u64
cpuusage_read(struct cgroup
*cgrp
, struct cftype
*cft
)
10740 struct cpuacct
*ca
= cgroup_ca(cgrp
);
10741 u64 totalcpuusage
= 0;
10744 for_each_present_cpu(i
)
10745 totalcpuusage
+= cpuacct_cpuusage_read(ca
, i
);
10747 return totalcpuusage
;
10750 static int cpuusage_write(struct cgroup
*cgrp
, struct cftype
*cftype
,
10753 struct cpuacct
*ca
= cgroup_ca(cgrp
);
10762 for_each_present_cpu(i
)
10763 cpuacct_cpuusage_write(ca
, i
, 0);
10769 static int cpuacct_percpu_seq_read(struct cgroup
*cgroup
, struct cftype
*cft
,
10770 struct seq_file
*m
)
10772 struct cpuacct
*ca
= cgroup_ca(cgroup
);
10776 for_each_present_cpu(i
) {
10777 percpu
= cpuacct_cpuusage_read(ca
, i
);
10778 seq_printf(m
, "%llu ", (unsigned long long) percpu
);
10780 seq_printf(m
, "\n");
10784 static const char *cpuacct_stat_desc
[] = {
10785 [CPUACCT_STAT_USER
] = "user",
10786 [CPUACCT_STAT_SYSTEM
] = "system",
10789 static int cpuacct_stats_show(struct cgroup
*cgrp
, struct cftype
*cft
,
10790 struct cgroup_map_cb
*cb
)
10792 struct cpuacct
*ca
= cgroup_ca(cgrp
);
10795 for (i
= 0; i
< CPUACCT_STAT_NSTATS
; i
++) {
10796 s64 val
= percpu_counter_read(&ca
->cpustat
[i
]);
10797 val
= cputime64_to_clock_t(val
);
10798 cb
->fill(cb
, cpuacct_stat_desc
[i
], val
);
10803 static struct cftype files
[] = {
10806 .read_u64
= cpuusage_read
,
10807 .write_u64
= cpuusage_write
,
10810 .name
= "usage_percpu",
10811 .read_seq_string
= cpuacct_percpu_seq_read
,
10815 .read_map
= cpuacct_stats_show
,
10819 static int cpuacct_populate(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
10821 return cgroup_add_files(cgrp
, ss
, files
, ARRAY_SIZE(files
));
10825 * charge this task's execution time to its accounting group.
10827 * called with rq->lock held.
10829 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
)
10831 struct cpuacct
*ca
;
10834 if (unlikely(!cpuacct_subsys
.active
))
10837 cpu
= task_cpu(tsk
);
10843 for (; ca
; ca
= ca
->parent
) {
10844 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
10845 *cpuusage
+= cputime
;
10852 * Charge the system/user time to the task's accounting group.
10854 static void cpuacct_update_stats(struct task_struct
*tsk
,
10855 enum cpuacct_stat_index idx
, cputime_t val
)
10857 struct cpuacct
*ca
;
10859 if (unlikely(!cpuacct_subsys
.active
))
10866 percpu_counter_add(&ca
->cpustat
[idx
], val
);
10872 struct cgroup_subsys cpuacct_subsys
= {
10874 .create
= cpuacct_create
,
10875 .destroy
= cpuacct_destroy
,
10876 .populate
= cpuacct_populate
,
10877 .subsys_id
= cpuacct_subsys_id
,
10879 #endif /* CONFIG_CGROUP_CPUACCT */
10883 int rcu_expedited_torture_stats(char *page
)
10887 EXPORT_SYMBOL_GPL(rcu_expedited_torture_stats
);
10889 void synchronize_sched_expedited(void)
10892 EXPORT_SYMBOL_GPL(synchronize_sched_expedited
);
10894 #else /* #ifndef CONFIG_SMP */
10896 static DEFINE_PER_CPU(struct migration_req
, rcu_migration_req
);
10897 static DEFINE_MUTEX(rcu_sched_expedited_mutex
);
10899 #define RCU_EXPEDITED_STATE_POST -2
10900 #define RCU_EXPEDITED_STATE_IDLE -1
10902 static int rcu_expedited_state
= RCU_EXPEDITED_STATE_IDLE
;
10904 int rcu_expedited_torture_stats(char *page
)
10909 cnt
+= sprintf(&page
[cnt
], "state: %d /", rcu_expedited_state
);
10910 for_each_online_cpu(cpu
) {
10911 cnt
+= sprintf(&page
[cnt
], " %d:%d",
10912 cpu
, per_cpu(rcu_migration_req
, cpu
).dest_cpu
);
10914 cnt
+= sprintf(&page
[cnt
], "\n");
10917 EXPORT_SYMBOL_GPL(rcu_expedited_torture_stats
);
10919 static long synchronize_sched_expedited_count
;
10922 * Wait for an rcu-sched grace period to elapse, but use "big hammer"
10923 * approach to force grace period to end quickly. This consumes
10924 * significant time on all CPUs, and is thus not recommended for
10925 * any sort of common-case code.
10927 * Note that it is illegal to call this function while holding any
10928 * lock that is acquired by a CPU-hotplug notifier. Failing to
10929 * observe this restriction will result in deadlock.
10931 void synchronize_sched_expedited(void)
10934 unsigned long flags
;
10935 bool need_full_sync
= 0;
10937 struct migration_req
*req
;
10941 smp_mb(); /* ensure prior mod happens before capturing snap. */
10942 snap
= ACCESS_ONCE(synchronize_sched_expedited_count
) + 1;
10944 while (!mutex_trylock(&rcu_sched_expedited_mutex
)) {
10946 if (trycount
++ < 10)
10947 udelay(trycount
* num_online_cpus());
10949 synchronize_sched();
10952 if (ACCESS_ONCE(synchronize_sched_expedited_count
) - snap
> 0) {
10953 smp_mb(); /* ensure test happens before caller kfree */
10958 rcu_expedited_state
= RCU_EXPEDITED_STATE_POST
;
10959 for_each_online_cpu(cpu
) {
10961 req
= &per_cpu(rcu_migration_req
, cpu
);
10962 init_completion(&req
->done
);
10964 req
->dest_cpu
= RCU_MIGRATION_NEED_QS
;
10965 raw_spin_lock_irqsave(&rq
->lock
, flags
);
10966 list_add(&req
->list
, &rq
->migration_queue
);
10967 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
10968 wake_up_process(rq
->migration_thread
);
10970 for_each_online_cpu(cpu
) {
10971 rcu_expedited_state
= cpu
;
10972 req
= &per_cpu(rcu_migration_req
, cpu
);
10974 wait_for_completion(&req
->done
);
10975 raw_spin_lock_irqsave(&rq
->lock
, flags
);
10976 if (unlikely(req
->dest_cpu
== RCU_MIGRATION_MUST_SYNC
))
10977 need_full_sync
= 1;
10978 req
->dest_cpu
= RCU_MIGRATION_IDLE
;
10979 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
10981 rcu_expedited_state
= RCU_EXPEDITED_STATE_IDLE
;
10982 synchronize_sched_expedited_count
++;
10983 mutex_unlock(&rcu_sched_expedited_mutex
);
10985 if (need_full_sync
)
10986 synchronize_sched();
10988 EXPORT_SYMBOL_GPL(synchronize_sched_expedited
);
10990 #endif /* #else #ifndef CONFIG_SMP */