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
);
2009 * Is this task likely cache-hot:
2012 task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
)
2016 if (p
->sched_class
!= &fair_sched_class
)
2020 * Buddy candidates are cache hot:
2022 if (sched_feat(CACHE_HOT_BUDDY
) && this_rq()->nr_running
&&
2023 (&p
->se
== cfs_rq_of(&p
->se
)->next
||
2024 &p
->se
== cfs_rq_of(&p
->se
)->last
))
2027 if (sysctl_sched_migration_cost
== -1)
2029 if (sysctl_sched_migration_cost
== 0)
2032 delta
= now
- p
->se
.exec_start
;
2034 return delta
< (s64
)sysctl_sched_migration_cost
;
2038 void set_task_cpu(struct task_struct
*p
, unsigned int new_cpu
)
2040 int old_cpu
= task_cpu(p
);
2041 struct cfs_rq
*old_cfsrq
= task_cfs_rq(p
),
2042 *new_cfsrq
= cpu_cfs_rq(old_cfsrq
, new_cpu
);
2044 #ifdef CONFIG_SCHED_DEBUG
2046 * We should never call set_task_cpu() on a blocked task,
2047 * ttwu() will sort out the placement.
2049 WARN_ON(p
->state
!= TASK_RUNNING
&& p
->state
!= TASK_WAKING
);
2052 trace_sched_migrate_task(p
, new_cpu
);
2054 if (old_cpu
!= new_cpu
) {
2055 p
->se
.nr_migrations
++;
2056 perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS
,
2059 p
->se
.vruntime
-= old_cfsrq
->min_vruntime
-
2060 new_cfsrq
->min_vruntime
;
2062 __set_task_cpu(p
, new_cpu
);
2065 struct migration_req
{
2066 struct list_head list
;
2068 struct task_struct
*task
;
2071 struct completion done
;
2075 * The task's runqueue lock must be held.
2076 * Returns true if you have to wait for migration thread.
2079 migrate_task(struct task_struct
*p
, int dest_cpu
, struct migration_req
*req
)
2081 struct rq
*rq
= task_rq(p
);
2084 * If the task is not on a runqueue (and not running), then
2085 * the next wake-up will properly place the task.
2087 if (!p
->se
.on_rq
&& !task_running(rq
, p
))
2090 init_completion(&req
->done
);
2092 req
->dest_cpu
= dest_cpu
;
2093 list_add(&req
->list
, &rq
->migration_queue
);
2099 * wait_task_context_switch - wait for a thread to complete at least one
2102 * @p must not be current.
2104 void wait_task_context_switch(struct task_struct
*p
)
2106 unsigned long nvcsw
, nivcsw
, flags
;
2114 * The runqueue is assigned before the actual context
2115 * switch. We need to take the runqueue lock.
2117 * We could check initially without the lock but it is
2118 * very likely that we need to take the lock in every
2121 rq
= task_rq_lock(p
, &flags
);
2122 running
= task_running(rq
, p
);
2123 task_rq_unlock(rq
, &flags
);
2125 if (likely(!running
))
2128 * The switch count is incremented before the actual
2129 * context switch. We thus wait for two switches to be
2130 * sure at least one completed.
2132 if ((p
->nvcsw
- nvcsw
) > 1)
2134 if ((p
->nivcsw
- nivcsw
) > 1)
2142 * wait_task_inactive - wait for a thread to unschedule.
2144 * If @match_state is nonzero, it's the @p->state value just checked and
2145 * not expected to change. If it changes, i.e. @p might have woken up,
2146 * then return zero. When we succeed in waiting for @p to be off its CPU,
2147 * we return a positive number (its total switch count). If a second call
2148 * a short while later returns the same number, the caller can be sure that
2149 * @p has remained unscheduled the whole time.
2151 * The caller must ensure that the task *will* unschedule sometime soon,
2152 * else this function might spin for a *long* time. This function can't
2153 * be called with interrupts off, or it may introduce deadlock with
2154 * smp_call_function() if an IPI is sent by the same process we are
2155 * waiting to become inactive.
2157 unsigned long wait_task_inactive(struct task_struct
*p
, long match_state
)
2159 unsigned long flags
;
2166 * We do the initial early heuristics without holding
2167 * any task-queue locks at all. We'll only try to get
2168 * the runqueue lock when things look like they will
2174 * If the task is actively running on another CPU
2175 * still, just relax and busy-wait without holding
2178 * NOTE! Since we don't hold any locks, it's not
2179 * even sure that "rq" stays as the right runqueue!
2180 * But we don't care, since "task_running()" will
2181 * return false if the runqueue has changed and p
2182 * is actually now running somewhere else!
2184 while (task_running(rq
, p
)) {
2185 if (match_state
&& unlikely(p
->state
!= match_state
))
2191 * Ok, time to look more closely! We need the rq
2192 * lock now, to be *sure*. If we're wrong, we'll
2193 * just go back and repeat.
2195 rq
= task_rq_lock(p
, &flags
);
2196 trace_sched_wait_task(rq
, p
);
2197 running
= task_running(rq
, p
);
2198 on_rq
= p
->se
.on_rq
;
2200 if (!match_state
|| p
->state
== match_state
)
2201 ncsw
= p
->nvcsw
| LONG_MIN
; /* sets MSB */
2202 task_rq_unlock(rq
, &flags
);
2205 * If it changed from the expected state, bail out now.
2207 if (unlikely(!ncsw
))
2211 * Was it really running after all now that we
2212 * checked with the proper locks actually held?
2214 * Oops. Go back and try again..
2216 if (unlikely(running
)) {
2222 * It's not enough that it's not actively running,
2223 * it must be off the runqueue _entirely_, and not
2226 * So if it was still runnable (but just not actively
2227 * running right now), it's preempted, and we should
2228 * yield - it could be a while.
2230 if (unlikely(on_rq
)) {
2231 schedule_timeout_uninterruptible(1);
2236 * Ahh, all good. It wasn't running, and it wasn't
2237 * runnable, which means that it will never become
2238 * running in the future either. We're all done!
2247 * kick_process - kick a running thread to enter/exit the kernel
2248 * @p: the to-be-kicked thread
2250 * Cause a process which is running on another CPU to enter
2251 * kernel-mode, without any delay. (to get signals handled.)
2253 * NOTE: this function doesnt have to take the runqueue lock,
2254 * because all it wants to ensure is that the remote task enters
2255 * the kernel. If the IPI races and the task has been migrated
2256 * to another CPU then no harm is done and the purpose has been
2259 void kick_process(struct task_struct
*p
)
2265 if ((cpu
!= smp_processor_id()) && task_curr(p
))
2266 smp_send_reschedule(cpu
);
2269 EXPORT_SYMBOL_GPL(kick_process
);
2270 #endif /* CONFIG_SMP */
2273 * task_oncpu_function_call - call a function on the cpu on which a task runs
2274 * @p: the task to evaluate
2275 * @func: the function to be called
2276 * @info: the function call argument
2278 * Calls the function @func when the task is currently running. This might
2279 * be on the current CPU, which just calls the function directly
2281 void task_oncpu_function_call(struct task_struct
*p
,
2282 void (*func
) (void *info
), void *info
)
2289 smp_call_function_single(cpu
, func
, info
, 1);
2294 static int select_fallback_rq(int cpu
, struct task_struct
*p
)
2297 const struct cpumask
*nodemask
= cpumask_of_node(cpu_to_node(cpu
));
2299 /* Look for allowed, online CPU in same node. */
2300 for_each_cpu_and(dest_cpu
, nodemask
, cpu_active_mask
)
2301 if (cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
))
2304 /* Any allowed, online CPU? */
2305 dest_cpu
= cpumask_any_and(&p
->cpus_allowed
, cpu_active_mask
);
2306 if (dest_cpu
< nr_cpu_ids
)
2309 /* No more Mr. Nice Guy. */
2310 if (dest_cpu
>= nr_cpu_ids
) {
2312 cpuset_cpus_allowed_locked(p
, &p
->cpus_allowed
);
2314 dest_cpu
= cpumask_any_and(cpu_active_mask
, &p
->cpus_allowed
);
2317 * Don't tell them about moving exiting tasks or
2318 * kernel threads (both mm NULL), since they never
2321 if (p
->mm
&& printk_ratelimit()) {
2322 printk(KERN_INFO
"process %d (%s) no "
2323 "longer affine to cpu%d\n",
2324 task_pid_nr(p
), p
->comm
, cpu
);
2334 * - fork, @p is stable because it isn't on the tasklist yet
2336 * - exec, @p is unstable, retry loop
2338 * - wake-up, we serialize ->cpus_allowed against TASK_WAKING so
2339 * we should be good.
2342 int select_task_rq(struct task_struct
*p
, int sd_flags
, int wake_flags
)
2344 int cpu
= p
->sched_class
->select_task_rq(p
, sd_flags
, wake_flags
);
2347 * In order not to call set_task_cpu() on a blocking task we need
2348 * to rely on ttwu() to place the task on a valid ->cpus_allowed
2351 * Since this is common to all placement strategies, this lives here.
2353 * [ this allows ->select_task() to simply return task_cpu(p) and
2354 * not worry about this generic constraint ]
2356 if (unlikely(!cpumask_test_cpu(cpu
, &p
->cpus_allowed
) ||
2358 cpu
= select_fallback_rq(task_cpu(p
), p
);
2365 * try_to_wake_up - wake up a thread
2366 * @p: the to-be-woken-up thread
2367 * @state: the mask of task states that can be woken
2368 * @sync: do a synchronous wakeup?
2370 * Put it on the run-queue if it's not already there. The "current"
2371 * thread is always on the run-queue (except when the actual
2372 * re-schedule is in progress), and as such you're allowed to do
2373 * the simpler "current->state = TASK_RUNNING" to mark yourself
2374 * runnable without the overhead of this.
2376 * returns failure only if the task is already active.
2378 static int try_to_wake_up(struct task_struct
*p
, unsigned int state
,
2381 int cpu
, orig_cpu
, this_cpu
, success
= 0;
2382 unsigned long flags
;
2383 struct rq
*rq
, *orig_rq
;
2385 if (!sched_feat(SYNC_WAKEUPS
))
2386 wake_flags
&= ~WF_SYNC
;
2388 this_cpu
= get_cpu();
2391 rq
= orig_rq
= task_rq_lock(p
, &flags
);
2392 update_rq_clock(rq
);
2393 if (!(p
->state
& state
))
2403 if (unlikely(task_running(rq
, p
)))
2407 * In order to handle concurrent wakeups and release the rq->lock
2408 * we put the task in TASK_WAKING state.
2410 * First fix up the nr_uninterruptible count:
2412 if (task_contributes_to_load(p
))
2413 rq
->nr_uninterruptible
--;
2414 p
->state
= TASK_WAKING
;
2415 __task_rq_unlock(rq
);
2417 cpu
= select_task_rq(p
, SD_BALANCE_WAKE
, wake_flags
);
2418 if (cpu
!= orig_cpu
)
2419 set_task_cpu(p
, cpu
);
2421 rq
= __task_rq_lock(p
);
2422 update_rq_clock(rq
);
2424 WARN_ON(p
->state
!= TASK_WAKING
);
2427 #ifdef CONFIG_SCHEDSTATS
2428 schedstat_inc(rq
, ttwu_count
);
2429 if (cpu
== this_cpu
)
2430 schedstat_inc(rq
, ttwu_local
);
2432 struct sched_domain
*sd
;
2433 for_each_domain(this_cpu
, sd
) {
2434 if (cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
2435 schedstat_inc(sd
, ttwu_wake_remote
);
2440 #endif /* CONFIG_SCHEDSTATS */
2443 #endif /* CONFIG_SMP */
2444 schedstat_inc(p
, se
.nr_wakeups
);
2445 if (wake_flags
& WF_SYNC
)
2446 schedstat_inc(p
, se
.nr_wakeups_sync
);
2447 if (orig_cpu
!= cpu
)
2448 schedstat_inc(p
, se
.nr_wakeups_migrate
);
2449 if (cpu
== this_cpu
)
2450 schedstat_inc(p
, se
.nr_wakeups_local
);
2452 schedstat_inc(p
, se
.nr_wakeups_remote
);
2453 activate_task(rq
, p
, 1);
2457 * Only attribute actual wakeups done by this task.
2459 if (!in_interrupt()) {
2460 struct sched_entity
*se
= ¤t
->se
;
2461 u64 sample
= se
->sum_exec_runtime
;
2463 if (se
->last_wakeup
)
2464 sample
-= se
->last_wakeup
;
2466 sample
-= se
->start_runtime
;
2467 update_avg(&se
->avg_wakeup
, sample
);
2469 se
->last_wakeup
= se
->sum_exec_runtime
;
2473 trace_sched_wakeup(rq
, p
, success
);
2474 check_preempt_curr(rq
, p
, wake_flags
);
2476 p
->state
= TASK_RUNNING
;
2478 if (p
->sched_class
->task_wake_up
)
2479 p
->sched_class
->task_wake_up(rq
, p
);
2481 if (unlikely(rq
->idle_stamp
)) {
2482 u64 delta
= rq
->clock
- rq
->idle_stamp
;
2483 u64 max
= 2*sysctl_sched_migration_cost
;
2488 update_avg(&rq
->avg_idle
, delta
);
2493 task_rq_unlock(rq
, &flags
);
2500 * wake_up_process - Wake up a specific process
2501 * @p: The process to be woken up.
2503 * Attempt to wake up the nominated process and move it to the set of runnable
2504 * processes. Returns 1 if the process was woken up, 0 if it was already
2507 * It may be assumed that this function implies a write memory barrier before
2508 * changing the task state if and only if any tasks are woken up.
2510 int wake_up_process(struct task_struct
*p
)
2512 return try_to_wake_up(p
, TASK_ALL
, 0);
2514 EXPORT_SYMBOL(wake_up_process
);
2516 int wake_up_state(struct task_struct
*p
, unsigned int state
)
2518 return try_to_wake_up(p
, state
, 0);
2522 * Perform scheduler related setup for a newly forked process p.
2523 * p is forked by current.
2525 * __sched_fork() is basic setup used by init_idle() too:
2527 static void __sched_fork(struct task_struct
*p
)
2529 p
->se
.exec_start
= 0;
2530 p
->se
.sum_exec_runtime
= 0;
2531 p
->se
.prev_sum_exec_runtime
= 0;
2532 p
->se
.nr_migrations
= 0;
2533 p
->se
.last_wakeup
= 0;
2534 p
->se
.avg_overlap
= 0;
2535 p
->se
.start_runtime
= 0;
2536 p
->se
.avg_wakeup
= sysctl_sched_wakeup_granularity
;
2538 #ifdef CONFIG_SCHEDSTATS
2539 p
->se
.wait_start
= 0;
2541 p
->se
.wait_count
= 0;
2544 p
->se
.sleep_start
= 0;
2545 p
->se
.sleep_max
= 0;
2546 p
->se
.sum_sleep_runtime
= 0;
2548 p
->se
.block_start
= 0;
2549 p
->se
.block_max
= 0;
2551 p
->se
.slice_max
= 0;
2553 p
->se
.nr_migrations_cold
= 0;
2554 p
->se
.nr_failed_migrations_affine
= 0;
2555 p
->se
.nr_failed_migrations_running
= 0;
2556 p
->se
.nr_failed_migrations_hot
= 0;
2557 p
->se
.nr_forced_migrations
= 0;
2559 p
->se
.nr_wakeups
= 0;
2560 p
->se
.nr_wakeups_sync
= 0;
2561 p
->se
.nr_wakeups_migrate
= 0;
2562 p
->se
.nr_wakeups_local
= 0;
2563 p
->se
.nr_wakeups_remote
= 0;
2564 p
->se
.nr_wakeups_affine
= 0;
2565 p
->se
.nr_wakeups_affine_attempts
= 0;
2566 p
->se
.nr_wakeups_passive
= 0;
2567 p
->se
.nr_wakeups_idle
= 0;
2571 INIT_LIST_HEAD(&p
->rt
.run_list
);
2573 INIT_LIST_HEAD(&p
->se
.group_node
);
2575 #ifdef CONFIG_PREEMPT_NOTIFIERS
2576 INIT_HLIST_HEAD(&p
->preempt_notifiers
);
2581 * fork()/clone()-time setup:
2583 void sched_fork(struct task_struct
*p
, int clone_flags
)
2585 int cpu
= get_cpu();
2589 * We mark the process as waking here. This guarantees that
2590 * nobody will actually run it, and a signal or other external
2591 * event cannot wake it up and insert it on the runqueue either.
2593 p
->state
= TASK_WAKING
;
2596 * Revert to default priority/policy on fork if requested.
2598 if (unlikely(p
->sched_reset_on_fork
)) {
2599 if (p
->policy
== SCHED_FIFO
|| p
->policy
== SCHED_RR
) {
2600 p
->policy
= SCHED_NORMAL
;
2601 p
->normal_prio
= p
->static_prio
;
2604 if (PRIO_TO_NICE(p
->static_prio
) < 0) {
2605 p
->static_prio
= NICE_TO_PRIO(0);
2606 p
->normal_prio
= p
->static_prio
;
2611 * We don't need the reset flag anymore after the fork. It has
2612 * fulfilled its duty:
2614 p
->sched_reset_on_fork
= 0;
2618 * Make sure we do not leak PI boosting priority to the child.
2620 p
->prio
= current
->normal_prio
;
2622 if (!rt_prio(p
->prio
))
2623 p
->sched_class
= &fair_sched_class
;
2625 if (p
->sched_class
->task_fork
)
2626 p
->sched_class
->task_fork(p
);
2629 cpu
= select_task_rq(p
, SD_BALANCE_FORK
, 0);
2631 set_task_cpu(p
, cpu
);
2633 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
2634 if (likely(sched_info_on()))
2635 memset(&p
->sched_info
, 0, sizeof(p
->sched_info
));
2637 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
2640 #ifdef CONFIG_PREEMPT
2641 /* Want to start with kernel preemption disabled. */
2642 task_thread_info(p
)->preempt_count
= 1;
2644 plist_node_init(&p
->pushable_tasks
, MAX_PRIO
);
2650 * wake_up_new_task - wake up a newly created task for the first time.
2652 * This function will do some initial scheduler statistics housekeeping
2653 * that must be done for every newly created context, then puts the task
2654 * on the runqueue and wakes it.
2656 void wake_up_new_task(struct task_struct
*p
, unsigned long clone_flags
)
2658 unsigned long flags
;
2661 rq
= task_rq_lock(p
, &flags
);
2662 BUG_ON(p
->state
!= TASK_WAKING
);
2663 p
->state
= TASK_RUNNING
;
2664 update_rq_clock(rq
);
2665 activate_task(rq
, p
, 0);
2666 trace_sched_wakeup_new(rq
, p
, 1);
2667 check_preempt_curr(rq
, p
, WF_FORK
);
2669 if (p
->sched_class
->task_wake_up
)
2670 p
->sched_class
->task_wake_up(rq
, p
);
2672 task_rq_unlock(rq
, &flags
);
2675 #ifdef CONFIG_PREEMPT_NOTIFIERS
2678 * preempt_notifier_register - tell me when current is being preempted & rescheduled
2679 * @notifier: notifier struct to register
2681 void preempt_notifier_register(struct preempt_notifier
*notifier
)
2683 hlist_add_head(¬ifier
->link
, ¤t
->preempt_notifiers
);
2685 EXPORT_SYMBOL_GPL(preempt_notifier_register
);
2688 * preempt_notifier_unregister - no longer interested in preemption notifications
2689 * @notifier: notifier struct to unregister
2691 * This is safe to call from within a preemption notifier.
2693 void preempt_notifier_unregister(struct preempt_notifier
*notifier
)
2695 hlist_del(¬ifier
->link
);
2697 EXPORT_SYMBOL_GPL(preempt_notifier_unregister
);
2699 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2701 struct preempt_notifier
*notifier
;
2702 struct hlist_node
*node
;
2704 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
2705 notifier
->ops
->sched_in(notifier
, raw_smp_processor_id());
2709 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2710 struct task_struct
*next
)
2712 struct preempt_notifier
*notifier
;
2713 struct hlist_node
*node
;
2715 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
2716 notifier
->ops
->sched_out(notifier
, next
);
2719 #else /* !CONFIG_PREEMPT_NOTIFIERS */
2721 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2726 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2727 struct task_struct
*next
)
2731 #endif /* CONFIG_PREEMPT_NOTIFIERS */
2734 * prepare_task_switch - prepare to switch tasks
2735 * @rq: the runqueue preparing to switch
2736 * @prev: the current task that is being switched out
2737 * @next: the task we are going to switch to.
2739 * This is called with the rq lock held and interrupts off. It must
2740 * be paired with a subsequent finish_task_switch after the context
2743 * prepare_task_switch sets up locking and calls architecture specific
2747 prepare_task_switch(struct rq
*rq
, struct task_struct
*prev
,
2748 struct task_struct
*next
)
2750 fire_sched_out_preempt_notifiers(prev
, next
);
2751 prepare_lock_switch(rq
, next
);
2752 prepare_arch_switch(next
);
2756 * finish_task_switch - clean up after a task-switch
2757 * @rq: runqueue associated with task-switch
2758 * @prev: the thread we just switched away from.
2760 * finish_task_switch must be called after the context switch, paired
2761 * with a prepare_task_switch call before the context switch.
2762 * finish_task_switch will reconcile locking set up by prepare_task_switch,
2763 * and do any other architecture-specific cleanup actions.
2765 * Note that we may have delayed dropping an mm in context_switch(). If
2766 * so, we finish that here outside of the runqueue lock. (Doing it
2767 * with the lock held can cause deadlocks; see schedule() for
2770 static void finish_task_switch(struct rq
*rq
, struct task_struct
*prev
)
2771 __releases(rq
->lock
)
2773 struct mm_struct
*mm
= rq
->prev_mm
;
2779 * A task struct has one reference for the use as "current".
2780 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
2781 * schedule one last time. The schedule call will never return, and
2782 * the scheduled task must drop that reference.
2783 * The test for TASK_DEAD must occur while the runqueue locks are
2784 * still held, otherwise prev could be scheduled on another cpu, die
2785 * there before we look at prev->state, and then the reference would
2787 * Manfred Spraul <manfred@colorfullife.com>
2789 prev_state
= prev
->state
;
2790 finish_arch_switch(prev
);
2791 perf_event_task_sched_in(current
, cpu_of(rq
));
2792 finish_lock_switch(rq
, prev
);
2794 fire_sched_in_preempt_notifiers(current
);
2797 if (unlikely(prev_state
== TASK_DEAD
)) {
2799 * Remove function-return probe instances associated with this
2800 * task and put them back on the free list.
2802 kprobe_flush_task(prev
);
2803 put_task_struct(prev
);
2809 /* assumes rq->lock is held */
2810 static inline void pre_schedule(struct rq
*rq
, struct task_struct
*prev
)
2812 if (prev
->sched_class
->pre_schedule
)
2813 prev
->sched_class
->pre_schedule(rq
, prev
);
2816 /* rq->lock is NOT held, but preemption is disabled */
2817 static inline void post_schedule(struct rq
*rq
)
2819 if (rq
->post_schedule
) {
2820 unsigned long flags
;
2822 raw_spin_lock_irqsave(&rq
->lock
, flags
);
2823 if (rq
->curr
->sched_class
->post_schedule
)
2824 rq
->curr
->sched_class
->post_schedule(rq
);
2825 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
2827 rq
->post_schedule
= 0;
2833 static inline void pre_schedule(struct rq
*rq
, struct task_struct
*p
)
2837 static inline void post_schedule(struct rq
*rq
)
2844 * schedule_tail - first thing a freshly forked thread must call.
2845 * @prev: the thread we just switched away from.
2847 asmlinkage
void schedule_tail(struct task_struct
*prev
)
2848 __releases(rq
->lock
)
2850 struct rq
*rq
= this_rq();
2852 finish_task_switch(rq
, prev
);
2855 * FIXME: do we need to worry about rq being invalidated by the
2860 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
2861 /* In this case, finish_task_switch does not reenable preemption */
2864 if (current
->set_child_tid
)
2865 put_user(task_pid_vnr(current
), current
->set_child_tid
);
2869 * context_switch - switch to the new MM and the new
2870 * thread's register state.
2873 context_switch(struct rq
*rq
, struct task_struct
*prev
,
2874 struct task_struct
*next
)
2876 struct mm_struct
*mm
, *oldmm
;
2878 prepare_task_switch(rq
, prev
, next
);
2879 trace_sched_switch(rq
, prev
, next
);
2881 oldmm
= prev
->active_mm
;
2883 * For paravirt, this is coupled with an exit in switch_to to
2884 * combine the page table reload and the switch backend into
2887 arch_start_context_switch(prev
);
2890 next
->active_mm
= oldmm
;
2891 atomic_inc(&oldmm
->mm_count
);
2892 enter_lazy_tlb(oldmm
, next
);
2894 switch_mm(oldmm
, mm
, next
);
2896 if (likely(!prev
->mm
)) {
2897 prev
->active_mm
= NULL
;
2898 rq
->prev_mm
= oldmm
;
2901 * Since the runqueue lock will be released by the next
2902 * task (which is an invalid locking op but in the case
2903 * of the scheduler it's an obvious special-case), so we
2904 * do an early lockdep release here:
2906 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
2907 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
2910 /* Here we just switch the register state and the stack. */
2911 switch_to(prev
, next
, prev
);
2915 * this_rq must be evaluated again because prev may have moved
2916 * CPUs since it called schedule(), thus the 'rq' on its stack
2917 * frame will be invalid.
2919 finish_task_switch(this_rq(), prev
);
2923 * nr_running, nr_uninterruptible and nr_context_switches:
2925 * externally visible scheduler statistics: current number of runnable
2926 * threads, current number of uninterruptible-sleeping threads, total
2927 * number of context switches performed since bootup.
2929 unsigned long nr_running(void)
2931 unsigned long i
, sum
= 0;
2933 for_each_online_cpu(i
)
2934 sum
+= cpu_rq(i
)->nr_running
;
2939 unsigned long nr_uninterruptible(void)
2941 unsigned long i
, sum
= 0;
2943 for_each_possible_cpu(i
)
2944 sum
+= cpu_rq(i
)->nr_uninterruptible
;
2947 * Since we read the counters lockless, it might be slightly
2948 * inaccurate. Do not allow it to go below zero though:
2950 if (unlikely((long)sum
< 0))
2956 unsigned long long nr_context_switches(void)
2959 unsigned long long sum
= 0;
2961 for_each_possible_cpu(i
)
2962 sum
+= cpu_rq(i
)->nr_switches
;
2967 unsigned long nr_iowait(void)
2969 unsigned long i
, sum
= 0;
2971 for_each_possible_cpu(i
)
2972 sum
+= atomic_read(&cpu_rq(i
)->nr_iowait
);
2977 unsigned long nr_iowait_cpu(void)
2979 struct rq
*this = this_rq();
2980 return atomic_read(&this->nr_iowait
);
2983 unsigned long this_cpu_load(void)
2985 struct rq
*this = this_rq();
2986 return this->cpu_load
[0];
2990 /* Variables and functions for calc_load */
2991 static atomic_long_t calc_load_tasks
;
2992 static unsigned long calc_load_update
;
2993 unsigned long avenrun
[3];
2994 EXPORT_SYMBOL(avenrun
);
2997 * get_avenrun - get the load average array
2998 * @loads: pointer to dest load array
2999 * @offset: offset to add
3000 * @shift: shift count to shift the result left
3002 * These values are estimates at best, so no need for locking.
3004 void get_avenrun(unsigned long *loads
, unsigned long offset
, int shift
)
3006 loads
[0] = (avenrun
[0] + offset
) << shift
;
3007 loads
[1] = (avenrun
[1] + offset
) << shift
;
3008 loads
[2] = (avenrun
[2] + offset
) << shift
;
3011 static unsigned long
3012 calc_load(unsigned long load
, unsigned long exp
, unsigned long active
)
3015 load
+= active
* (FIXED_1
- exp
);
3016 return load
>> FSHIFT
;
3020 * calc_load - update the avenrun load estimates 10 ticks after the
3021 * CPUs have updated calc_load_tasks.
3023 void calc_global_load(void)
3025 unsigned long upd
= calc_load_update
+ 10;
3028 if (time_before(jiffies
, upd
))
3031 active
= atomic_long_read(&calc_load_tasks
);
3032 active
= active
> 0 ? active
* FIXED_1
: 0;
3034 avenrun
[0] = calc_load(avenrun
[0], EXP_1
, active
);
3035 avenrun
[1] = calc_load(avenrun
[1], EXP_5
, active
);
3036 avenrun
[2] = calc_load(avenrun
[2], EXP_15
, active
);
3038 calc_load_update
+= LOAD_FREQ
;
3042 * Either called from update_cpu_load() or from a cpu going idle
3044 static void calc_load_account_active(struct rq
*this_rq
)
3046 long nr_active
, delta
;
3048 nr_active
= this_rq
->nr_running
;
3049 nr_active
+= (long) this_rq
->nr_uninterruptible
;
3051 if (nr_active
!= this_rq
->calc_load_active
) {
3052 delta
= nr_active
- this_rq
->calc_load_active
;
3053 this_rq
->calc_load_active
= nr_active
;
3054 atomic_long_add(delta
, &calc_load_tasks
);
3059 * Update rq->cpu_load[] statistics. This function is usually called every
3060 * scheduler tick (TICK_NSEC).
3062 static void update_cpu_load(struct rq
*this_rq
)
3064 unsigned long this_load
= this_rq
->load
.weight
;
3067 this_rq
->nr_load_updates
++;
3069 /* Update our load: */
3070 for (i
= 0, scale
= 1; i
< CPU_LOAD_IDX_MAX
; i
++, scale
+= scale
) {
3071 unsigned long old_load
, new_load
;
3073 /* scale is effectively 1 << i now, and >> i divides by scale */
3075 old_load
= this_rq
->cpu_load
[i
];
3076 new_load
= this_load
;
3078 * Round up the averaging division if load is increasing. This
3079 * prevents us from getting stuck on 9 if the load is 10, for
3082 if (new_load
> old_load
)
3083 new_load
+= scale
-1;
3084 this_rq
->cpu_load
[i
] = (old_load
*(scale
-1) + new_load
) >> i
;
3087 if (time_after_eq(jiffies
, this_rq
->calc_load_update
)) {
3088 this_rq
->calc_load_update
+= LOAD_FREQ
;
3089 calc_load_account_active(this_rq
);
3096 * double_rq_lock - safely lock two runqueues
3098 * Note this does not disable interrupts like task_rq_lock,
3099 * you need to do so manually before calling.
3101 static void double_rq_lock(struct rq
*rq1
, struct rq
*rq2
)
3102 __acquires(rq1
->lock
)
3103 __acquires(rq2
->lock
)
3105 BUG_ON(!irqs_disabled());
3107 raw_spin_lock(&rq1
->lock
);
3108 __acquire(rq2
->lock
); /* Fake it out ;) */
3111 raw_spin_lock(&rq1
->lock
);
3112 raw_spin_lock_nested(&rq2
->lock
, SINGLE_DEPTH_NESTING
);
3114 raw_spin_lock(&rq2
->lock
);
3115 raw_spin_lock_nested(&rq1
->lock
, SINGLE_DEPTH_NESTING
);
3118 update_rq_clock(rq1
);
3119 update_rq_clock(rq2
);
3123 * double_rq_unlock - safely unlock two runqueues
3125 * Note this does not restore interrupts like task_rq_unlock,
3126 * you need to do so manually after calling.
3128 static void double_rq_unlock(struct rq
*rq1
, struct rq
*rq2
)
3129 __releases(rq1
->lock
)
3130 __releases(rq2
->lock
)
3132 raw_spin_unlock(&rq1
->lock
);
3134 raw_spin_unlock(&rq2
->lock
);
3136 __release(rq2
->lock
);
3140 * sched_exec - execve() is a valuable balancing opportunity, because at
3141 * this point the task has the smallest effective memory and cache footprint.
3143 void sched_exec(void)
3145 struct task_struct
*p
= current
;
3146 struct migration_req req
;
3147 int dest_cpu
, this_cpu
;
3148 unsigned long flags
;
3152 this_cpu
= get_cpu();
3153 dest_cpu
= select_task_rq(p
, SD_BALANCE_EXEC
, 0);
3154 if (dest_cpu
== this_cpu
) {
3159 rq
= task_rq_lock(p
, &flags
);
3163 * select_task_rq() can race against ->cpus_allowed
3165 if (!cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
)
3166 || unlikely(!cpu_active(dest_cpu
))) {
3167 task_rq_unlock(rq
, &flags
);
3171 /* force the process onto the specified CPU */
3172 if (migrate_task(p
, dest_cpu
, &req
)) {
3173 /* Need to wait for migration thread (might exit: take ref). */
3174 struct task_struct
*mt
= rq
->migration_thread
;
3176 get_task_struct(mt
);
3177 task_rq_unlock(rq
, &flags
);
3178 wake_up_process(mt
);
3179 put_task_struct(mt
);
3180 wait_for_completion(&req
.done
);
3184 task_rq_unlock(rq
, &flags
);
3188 * pull_task - move a task from a remote runqueue to the local runqueue.
3189 * Both runqueues must be locked.
3191 static void pull_task(struct rq
*src_rq
, struct task_struct
*p
,
3192 struct rq
*this_rq
, int this_cpu
)
3194 deactivate_task(src_rq
, p
, 0);
3195 set_task_cpu(p
, this_cpu
);
3196 activate_task(this_rq
, p
, 0);
3197 check_preempt_curr(this_rq
, p
, 0);
3201 * can_migrate_task - may task p from runqueue rq be migrated to this_cpu?
3204 int can_migrate_task(struct task_struct
*p
, struct rq
*rq
, int this_cpu
,
3205 struct sched_domain
*sd
, enum cpu_idle_type idle
,
3208 int tsk_cache_hot
= 0;
3210 * We do not migrate tasks that are:
3211 * 1) running (obviously), or
3212 * 2) cannot be migrated to this CPU due to cpus_allowed, or
3213 * 3) are cache-hot on their current CPU.
3215 if (!cpumask_test_cpu(this_cpu
, &p
->cpus_allowed
)) {
3216 schedstat_inc(p
, se
.nr_failed_migrations_affine
);
3221 if (task_running(rq
, p
)) {
3222 schedstat_inc(p
, se
.nr_failed_migrations_running
);
3227 * Aggressive migration if:
3228 * 1) task is cache cold, or
3229 * 2) too many balance attempts have failed.
3232 tsk_cache_hot
= task_hot(p
, rq
->clock
, sd
);
3233 if (!tsk_cache_hot
||
3234 sd
->nr_balance_failed
> sd
->cache_nice_tries
) {
3235 #ifdef CONFIG_SCHEDSTATS
3236 if (tsk_cache_hot
) {
3237 schedstat_inc(sd
, lb_hot_gained
[idle
]);
3238 schedstat_inc(p
, se
.nr_forced_migrations
);
3244 if (tsk_cache_hot
) {
3245 schedstat_inc(p
, se
.nr_failed_migrations_hot
);
3251 static unsigned long
3252 balance_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
3253 unsigned long max_load_move
, struct sched_domain
*sd
,
3254 enum cpu_idle_type idle
, int *all_pinned
,
3255 int *this_best_prio
, struct rq_iterator
*iterator
)
3257 int loops
= 0, pulled
= 0, pinned
= 0;
3258 struct task_struct
*p
;
3259 long rem_load_move
= max_load_move
;
3261 if (max_load_move
== 0)
3267 * Start the load-balancing iterator:
3269 p
= iterator
->start(iterator
->arg
);
3271 if (!p
|| loops
++ > sysctl_sched_nr_migrate
)
3274 if ((p
->se
.load
.weight
>> 1) > rem_load_move
||
3275 !can_migrate_task(p
, busiest
, this_cpu
, sd
, idle
, &pinned
)) {
3276 p
= iterator
->next(iterator
->arg
);
3280 pull_task(busiest
, p
, this_rq
, this_cpu
);
3282 rem_load_move
-= p
->se
.load
.weight
;
3284 #ifdef CONFIG_PREEMPT
3286 * NEWIDLE balancing is a source of latency, so preemptible kernels
3287 * will stop after the first task is pulled to minimize the critical
3290 if (idle
== CPU_NEWLY_IDLE
)
3295 * We only want to steal up to the prescribed amount of weighted load.
3297 if (rem_load_move
> 0) {
3298 if (p
->prio
< *this_best_prio
)
3299 *this_best_prio
= p
->prio
;
3300 p
= iterator
->next(iterator
->arg
);
3305 * Right now, this is one of only two places pull_task() is called,
3306 * so we can safely collect pull_task() stats here rather than
3307 * inside pull_task().
3309 schedstat_add(sd
, lb_gained
[idle
], pulled
);
3312 *all_pinned
= pinned
;
3314 return max_load_move
- rem_load_move
;
3318 * move_tasks tries to move up to max_load_move weighted load from busiest to
3319 * this_rq, as part of a balancing operation within domain "sd".
3320 * Returns 1 if successful and 0 otherwise.
3322 * Called with both runqueues locked.
3324 static int move_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
3325 unsigned long max_load_move
,
3326 struct sched_domain
*sd
, enum cpu_idle_type idle
,
3329 const struct sched_class
*class = sched_class_highest
;
3330 unsigned long total_load_moved
= 0;
3331 int this_best_prio
= this_rq
->curr
->prio
;
3335 class->load_balance(this_rq
, this_cpu
, busiest
,
3336 max_load_move
- total_load_moved
,
3337 sd
, idle
, all_pinned
, &this_best_prio
);
3338 class = class->next
;
3340 #ifdef CONFIG_PREEMPT
3342 * NEWIDLE balancing is a source of latency, so preemptible
3343 * kernels will stop after the first task is pulled to minimize
3344 * the critical section.
3346 if (idle
== CPU_NEWLY_IDLE
&& this_rq
->nr_running
)
3349 } while (class && max_load_move
> total_load_moved
);
3351 return total_load_moved
> 0;
3355 iter_move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
3356 struct sched_domain
*sd
, enum cpu_idle_type idle
,
3357 struct rq_iterator
*iterator
)
3359 struct task_struct
*p
= iterator
->start(iterator
->arg
);
3363 if (can_migrate_task(p
, busiest
, this_cpu
, sd
, idle
, &pinned
)) {
3364 pull_task(busiest
, p
, this_rq
, this_cpu
);
3366 * Right now, this is only the second place pull_task()
3367 * is called, so we can safely collect pull_task()
3368 * stats here rather than inside pull_task().
3370 schedstat_inc(sd
, lb_gained
[idle
]);
3374 p
= iterator
->next(iterator
->arg
);
3381 * move_one_task tries to move exactly one task from busiest to this_rq, as
3382 * part of active balancing operations within "domain".
3383 * Returns 1 if successful and 0 otherwise.
3385 * Called with both runqueues locked.
3387 static int move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
3388 struct sched_domain
*sd
, enum cpu_idle_type idle
)
3390 const struct sched_class
*class;
3392 for_each_class(class) {
3393 if (class->move_one_task(this_rq
, this_cpu
, busiest
, sd
, idle
))
3399 /********** Helpers for find_busiest_group ************************/
3401 * sd_lb_stats - Structure to store the statistics of a sched_domain
3402 * during load balancing.
3404 struct sd_lb_stats
{
3405 struct sched_group
*busiest
; /* Busiest group in this sd */
3406 struct sched_group
*this; /* Local group in this sd */
3407 unsigned long total_load
; /* Total load of all groups in sd */
3408 unsigned long total_pwr
; /* Total power of all groups in sd */
3409 unsigned long avg_load
; /* Average load across all groups in sd */
3411 /** Statistics of this group */
3412 unsigned long this_load
;
3413 unsigned long this_load_per_task
;
3414 unsigned long this_nr_running
;
3416 /* Statistics of the busiest group */
3417 unsigned long max_load
;
3418 unsigned long busiest_load_per_task
;
3419 unsigned long busiest_nr_running
;
3421 int group_imb
; /* Is there imbalance in this sd */
3422 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3423 int power_savings_balance
; /* Is powersave balance needed for this sd */
3424 struct sched_group
*group_min
; /* Least loaded group in sd */
3425 struct sched_group
*group_leader
; /* Group which relieves group_min */
3426 unsigned long min_load_per_task
; /* load_per_task in group_min */
3427 unsigned long leader_nr_running
; /* Nr running of group_leader */
3428 unsigned long min_nr_running
; /* Nr running of group_min */
3433 * sg_lb_stats - stats of a sched_group required for load_balancing
3435 struct sg_lb_stats
{
3436 unsigned long avg_load
; /*Avg load across the CPUs of the group */
3437 unsigned long group_load
; /* Total load over the CPUs of the group */
3438 unsigned long sum_nr_running
; /* Nr tasks running in the group */
3439 unsigned long sum_weighted_load
; /* Weighted load of group's tasks */
3440 unsigned long group_capacity
;
3441 int group_imb
; /* Is there an imbalance in the group ? */
3445 * group_first_cpu - Returns the first cpu in the cpumask of a sched_group.
3446 * @group: The group whose first cpu is to be returned.
3448 static inline unsigned int group_first_cpu(struct sched_group
*group
)
3450 return cpumask_first(sched_group_cpus(group
));
3454 * get_sd_load_idx - Obtain the load index for a given sched domain.
3455 * @sd: The sched_domain whose load_idx is to be obtained.
3456 * @idle: The Idle status of the CPU for whose sd load_icx is obtained.
3458 static inline int get_sd_load_idx(struct sched_domain
*sd
,
3459 enum cpu_idle_type idle
)
3465 load_idx
= sd
->busy_idx
;
3468 case CPU_NEWLY_IDLE
:
3469 load_idx
= sd
->newidle_idx
;
3472 load_idx
= sd
->idle_idx
;
3480 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3482 * init_sd_power_savings_stats - Initialize power savings statistics for
3483 * the given sched_domain, during load balancing.
3485 * @sd: Sched domain whose power-savings statistics are to be initialized.
3486 * @sds: Variable containing the statistics for sd.
3487 * @idle: Idle status of the CPU at which we're performing load-balancing.
3489 static inline void init_sd_power_savings_stats(struct sched_domain
*sd
,
3490 struct sd_lb_stats
*sds
, enum cpu_idle_type idle
)
3493 * Busy processors will not participate in power savings
3496 if (idle
== CPU_NOT_IDLE
|| !(sd
->flags
& SD_POWERSAVINGS_BALANCE
))
3497 sds
->power_savings_balance
= 0;
3499 sds
->power_savings_balance
= 1;
3500 sds
->min_nr_running
= ULONG_MAX
;
3501 sds
->leader_nr_running
= 0;
3506 * update_sd_power_savings_stats - Update the power saving stats for a
3507 * sched_domain while performing load balancing.
3509 * @group: sched_group belonging to the sched_domain under consideration.
3510 * @sds: Variable containing the statistics of the sched_domain
3511 * @local_group: Does group contain the CPU for which we're performing
3513 * @sgs: Variable containing the statistics of the group.
3515 static inline void update_sd_power_savings_stats(struct sched_group
*group
,
3516 struct sd_lb_stats
*sds
, int local_group
, struct sg_lb_stats
*sgs
)
3519 if (!sds
->power_savings_balance
)
3523 * If the local group is idle or completely loaded
3524 * no need to do power savings balance at this domain
3526 if (local_group
&& (sds
->this_nr_running
>= sgs
->group_capacity
||
3527 !sds
->this_nr_running
))
3528 sds
->power_savings_balance
= 0;
3531 * If a group is already running at full capacity or idle,
3532 * don't include that group in power savings calculations
3534 if (!sds
->power_savings_balance
||
3535 sgs
->sum_nr_running
>= sgs
->group_capacity
||
3536 !sgs
->sum_nr_running
)
3540 * Calculate the group which has the least non-idle load.
3541 * This is the group from where we need to pick up the load
3544 if ((sgs
->sum_nr_running
< sds
->min_nr_running
) ||
3545 (sgs
->sum_nr_running
== sds
->min_nr_running
&&
3546 group_first_cpu(group
) > group_first_cpu(sds
->group_min
))) {
3547 sds
->group_min
= group
;
3548 sds
->min_nr_running
= sgs
->sum_nr_running
;
3549 sds
->min_load_per_task
= sgs
->sum_weighted_load
/
3550 sgs
->sum_nr_running
;
3554 * Calculate the group which is almost near its
3555 * capacity but still has some space to pick up some load
3556 * from other group and save more power
3558 if (sgs
->sum_nr_running
+ 1 > sgs
->group_capacity
)
3561 if (sgs
->sum_nr_running
> sds
->leader_nr_running
||
3562 (sgs
->sum_nr_running
== sds
->leader_nr_running
&&
3563 group_first_cpu(group
) < group_first_cpu(sds
->group_leader
))) {
3564 sds
->group_leader
= group
;
3565 sds
->leader_nr_running
= sgs
->sum_nr_running
;
3570 * check_power_save_busiest_group - see if there is potential for some power-savings balance
3571 * @sds: Variable containing the statistics of the sched_domain
3572 * under consideration.
3573 * @this_cpu: Cpu at which we're currently performing load-balancing.
3574 * @imbalance: Variable to store the imbalance.
3577 * Check if we have potential to perform some power-savings balance.
3578 * If yes, set the busiest group to be the least loaded group in the
3579 * sched_domain, so that it's CPUs can be put to idle.
3581 * Returns 1 if there is potential to perform power-savings balance.
3584 static inline int check_power_save_busiest_group(struct sd_lb_stats
*sds
,
3585 int this_cpu
, unsigned long *imbalance
)
3587 if (!sds
->power_savings_balance
)
3590 if (sds
->this != sds
->group_leader
||
3591 sds
->group_leader
== sds
->group_min
)
3594 *imbalance
= sds
->min_load_per_task
;
3595 sds
->busiest
= sds
->group_min
;
3600 #else /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
3601 static inline void init_sd_power_savings_stats(struct sched_domain
*sd
,
3602 struct sd_lb_stats
*sds
, enum cpu_idle_type idle
)
3607 static inline void update_sd_power_savings_stats(struct sched_group
*group
,
3608 struct sd_lb_stats
*sds
, int local_group
, struct sg_lb_stats
*sgs
)
3613 static inline int check_power_save_busiest_group(struct sd_lb_stats
*sds
,
3614 int this_cpu
, unsigned long *imbalance
)
3618 #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
3621 unsigned long default_scale_freq_power(struct sched_domain
*sd
, int cpu
)
3623 return SCHED_LOAD_SCALE
;
3626 unsigned long __weak
arch_scale_freq_power(struct sched_domain
*sd
, int cpu
)
3628 return default_scale_freq_power(sd
, cpu
);
3631 unsigned long default_scale_smt_power(struct sched_domain
*sd
, int cpu
)
3633 unsigned long weight
= cpumask_weight(sched_domain_span(sd
));
3634 unsigned long smt_gain
= sd
->smt_gain
;
3641 unsigned long __weak
arch_scale_smt_power(struct sched_domain
*sd
, int cpu
)
3643 return default_scale_smt_power(sd
, cpu
);
3646 unsigned long scale_rt_power(int cpu
)
3648 struct rq
*rq
= cpu_rq(cpu
);
3649 u64 total
, available
;
3651 sched_avg_update(rq
);
3653 total
= sched_avg_period() + (rq
->clock
- rq
->age_stamp
);
3654 available
= total
- rq
->rt_avg
;
3656 if (unlikely((s64
)total
< SCHED_LOAD_SCALE
))
3657 total
= SCHED_LOAD_SCALE
;
3659 total
>>= SCHED_LOAD_SHIFT
;
3661 return div_u64(available
, total
);
3664 static void update_cpu_power(struct sched_domain
*sd
, int cpu
)
3666 unsigned long weight
= cpumask_weight(sched_domain_span(sd
));
3667 unsigned long power
= SCHED_LOAD_SCALE
;
3668 struct sched_group
*sdg
= sd
->groups
;
3670 if (sched_feat(ARCH_POWER
))
3671 power
*= arch_scale_freq_power(sd
, cpu
);
3673 power
*= default_scale_freq_power(sd
, cpu
);
3675 power
>>= SCHED_LOAD_SHIFT
;
3677 if ((sd
->flags
& SD_SHARE_CPUPOWER
) && weight
> 1) {
3678 if (sched_feat(ARCH_POWER
))
3679 power
*= arch_scale_smt_power(sd
, cpu
);
3681 power
*= default_scale_smt_power(sd
, cpu
);
3683 power
>>= SCHED_LOAD_SHIFT
;
3686 power
*= scale_rt_power(cpu
);
3687 power
>>= SCHED_LOAD_SHIFT
;
3692 sdg
->cpu_power
= power
;
3695 static void update_group_power(struct sched_domain
*sd
, int cpu
)
3697 struct sched_domain
*child
= sd
->child
;
3698 struct sched_group
*group
, *sdg
= sd
->groups
;
3699 unsigned long power
;
3702 update_cpu_power(sd
, cpu
);
3708 group
= child
->groups
;
3710 power
+= group
->cpu_power
;
3711 group
= group
->next
;
3712 } while (group
!= child
->groups
);
3714 sdg
->cpu_power
= power
;
3718 * update_sg_lb_stats - Update sched_group's statistics for load balancing.
3719 * @sd: The sched_domain whose statistics are to be updated.
3720 * @group: sched_group whose statistics are to be updated.
3721 * @this_cpu: Cpu for which load balance is currently performed.
3722 * @idle: Idle status of this_cpu
3723 * @load_idx: Load index of sched_domain of this_cpu for load calc.
3724 * @sd_idle: Idle status of the sched_domain containing group.
3725 * @local_group: Does group contain this_cpu.
3726 * @cpus: Set of cpus considered for load balancing.
3727 * @balance: Should we balance.
3728 * @sgs: variable to hold the statistics for this group.
3730 static inline void update_sg_lb_stats(struct sched_domain
*sd
,
3731 struct sched_group
*group
, int this_cpu
,
3732 enum cpu_idle_type idle
, int load_idx
, int *sd_idle
,
3733 int local_group
, const struct cpumask
*cpus
,
3734 int *balance
, struct sg_lb_stats
*sgs
)
3736 unsigned long load
, max_cpu_load
, min_cpu_load
;
3738 unsigned int balance_cpu
= -1, first_idle_cpu
= 0;
3739 unsigned long sum_avg_load_per_task
;
3740 unsigned long avg_load_per_task
;
3743 balance_cpu
= group_first_cpu(group
);
3744 if (balance_cpu
== this_cpu
)
3745 update_group_power(sd
, this_cpu
);
3748 /* Tally up the load of all CPUs in the group */
3749 sum_avg_load_per_task
= avg_load_per_task
= 0;
3751 min_cpu_load
= ~0UL;
3753 for_each_cpu_and(i
, sched_group_cpus(group
), cpus
) {
3754 struct rq
*rq
= cpu_rq(i
);
3756 if (*sd_idle
&& rq
->nr_running
)
3759 /* Bias balancing toward cpus of our domain */
3761 if (idle_cpu(i
) && !first_idle_cpu
) {
3766 load
= target_load(i
, load_idx
);
3768 load
= source_load(i
, load_idx
);
3769 if (load
> max_cpu_load
)
3770 max_cpu_load
= load
;
3771 if (min_cpu_load
> load
)
3772 min_cpu_load
= load
;
3775 sgs
->group_load
+= load
;
3776 sgs
->sum_nr_running
+= rq
->nr_running
;
3777 sgs
->sum_weighted_load
+= weighted_cpuload(i
);
3779 sum_avg_load_per_task
+= cpu_avg_load_per_task(i
);
3783 * First idle cpu or the first cpu(busiest) in this sched group
3784 * is eligible for doing load balancing at this and above
3785 * domains. In the newly idle case, we will allow all the cpu's
3786 * to do the newly idle load balance.
3788 if (idle
!= CPU_NEWLY_IDLE
&& local_group
&&
3789 balance_cpu
!= this_cpu
&& balance
) {
3794 /* Adjust by relative CPU power of the group */
3795 sgs
->avg_load
= (sgs
->group_load
* SCHED_LOAD_SCALE
) / group
->cpu_power
;
3799 * Consider the group unbalanced when the imbalance is larger
3800 * than the average weight of two tasks.
3802 * APZ: with cgroup the avg task weight can vary wildly and
3803 * might not be a suitable number - should we keep a
3804 * normalized nr_running number somewhere that negates
3807 avg_load_per_task
= (sum_avg_load_per_task
* SCHED_LOAD_SCALE
) /
3810 if ((max_cpu_load
- min_cpu_load
) > 2*avg_load_per_task
)
3813 sgs
->group_capacity
=
3814 DIV_ROUND_CLOSEST(group
->cpu_power
, SCHED_LOAD_SCALE
);
3818 * update_sd_lb_stats - Update sched_group's statistics for load balancing.
3819 * @sd: sched_domain whose statistics are to be updated.
3820 * @this_cpu: Cpu for which load balance is currently performed.
3821 * @idle: Idle status of this_cpu
3822 * @sd_idle: Idle status of the sched_domain containing group.
3823 * @cpus: Set of cpus considered for load balancing.
3824 * @balance: Should we balance.
3825 * @sds: variable to hold the statistics for this sched_domain.
3827 static inline void update_sd_lb_stats(struct sched_domain
*sd
, int this_cpu
,
3828 enum cpu_idle_type idle
, int *sd_idle
,
3829 const struct cpumask
*cpus
, int *balance
,
3830 struct sd_lb_stats
*sds
)
3832 struct sched_domain
*child
= sd
->child
;
3833 struct sched_group
*group
= sd
->groups
;
3834 struct sg_lb_stats sgs
;
3835 int load_idx
, prefer_sibling
= 0;
3837 if (child
&& child
->flags
& SD_PREFER_SIBLING
)
3840 init_sd_power_savings_stats(sd
, sds
, idle
);
3841 load_idx
= get_sd_load_idx(sd
, idle
);
3846 local_group
= cpumask_test_cpu(this_cpu
,
3847 sched_group_cpus(group
));
3848 memset(&sgs
, 0, sizeof(sgs
));
3849 update_sg_lb_stats(sd
, group
, this_cpu
, idle
, load_idx
, sd_idle
,
3850 local_group
, cpus
, balance
, &sgs
);
3852 if (local_group
&& balance
&& !(*balance
))
3855 sds
->total_load
+= sgs
.group_load
;
3856 sds
->total_pwr
+= group
->cpu_power
;
3859 * In case the child domain prefers tasks go to siblings
3860 * first, lower the group capacity to one so that we'll try
3861 * and move all the excess tasks away.
3864 sgs
.group_capacity
= min(sgs
.group_capacity
, 1UL);
3867 sds
->this_load
= sgs
.avg_load
;
3869 sds
->this_nr_running
= sgs
.sum_nr_running
;
3870 sds
->this_load_per_task
= sgs
.sum_weighted_load
;
3871 } else if (sgs
.avg_load
> sds
->max_load
&&
3872 (sgs
.sum_nr_running
> sgs
.group_capacity
||
3874 sds
->max_load
= sgs
.avg_load
;
3875 sds
->busiest
= group
;
3876 sds
->busiest_nr_running
= sgs
.sum_nr_running
;
3877 sds
->busiest_load_per_task
= sgs
.sum_weighted_load
;
3878 sds
->group_imb
= sgs
.group_imb
;
3881 update_sd_power_savings_stats(group
, sds
, local_group
, &sgs
);
3882 group
= group
->next
;
3883 } while (group
!= sd
->groups
);
3887 * fix_small_imbalance - Calculate the minor imbalance that exists
3888 * amongst the groups of a sched_domain, during
3890 * @sds: Statistics of the sched_domain whose imbalance is to be calculated.
3891 * @this_cpu: The cpu at whose sched_domain we're performing load-balance.
3892 * @imbalance: Variable to store the imbalance.
3894 static inline void fix_small_imbalance(struct sd_lb_stats
*sds
,
3895 int this_cpu
, unsigned long *imbalance
)
3897 unsigned long tmp
, pwr_now
= 0, pwr_move
= 0;
3898 unsigned int imbn
= 2;
3900 if (sds
->this_nr_running
) {
3901 sds
->this_load_per_task
/= sds
->this_nr_running
;
3902 if (sds
->busiest_load_per_task
>
3903 sds
->this_load_per_task
)
3906 sds
->this_load_per_task
=
3907 cpu_avg_load_per_task(this_cpu
);
3909 if (sds
->max_load
- sds
->this_load
+ sds
->busiest_load_per_task
>=
3910 sds
->busiest_load_per_task
* imbn
) {
3911 *imbalance
= sds
->busiest_load_per_task
;
3916 * OK, we don't have enough imbalance to justify moving tasks,
3917 * however we may be able to increase total CPU power used by
3921 pwr_now
+= sds
->busiest
->cpu_power
*
3922 min(sds
->busiest_load_per_task
, sds
->max_load
);
3923 pwr_now
+= sds
->this->cpu_power
*
3924 min(sds
->this_load_per_task
, sds
->this_load
);
3925 pwr_now
/= SCHED_LOAD_SCALE
;
3927 /* Amount of load we'd subtract */
3928 tmp
= (sds
->busiest_load_per_task
* SCHED_LOAD_SCALE
) /
3929 sds
->busiest
->cpu_power
;
3930 if (sds
->max_load
> tmp
)
3931 pwr_move
+= sds
->busiest
->cpu_power
*
3932 min(sds
->busiest_load_per_task
, sds
->max_load
- tmp
);
3934 /* Amount of load we'd add */
3935 if (sds
->max_load
* sds
->busiest
->cpu_power
<
3936 sds
->busiest_load_per_task
* SCHED_LOAD_SCALE
)
3937 tmp
= (sds
->max_load
* sds
->busiest
->cpu_power
) /
3938 sds
->this->cpu_power
;
3940 tmp
= (sds
->busiest_load_per_task
* SCHED_LOAD_SCALE
) /
3941 sds
->this->cpu_power
;
3942 pwr_move
+= sds
->this->cpu_power
*
3943 min(sds
->this_load_per_task
, sds
->this_load
+ tmp
);
3944 pwr_move
/= SCHED_LOAD_SCALE
;
3946 /* Move if we gain throughput */
3947 if (pwr_move
> pwr_now
)
3948 *imbalance
= sds
->busiest_load_per_task
;
3952 * calculate_imbalance - Calculate the amount of imbalance present within the
3953 * groups of a given sched_domain during load balance.
3954 * @sds: statistics of the sched_domain whose imbalance is to be calculated.
3955 * @this_cpu: Cpu for which currently load balance is being performed.
3956 * @imbalance: The variable to store the imbalance.
3958 static inline void calculate_imbalance(struct sd_lb_stats
*sds
, int this_cpu
,
3959 unsigned long *imbalance
)
3961 unsigned long max_pull
;
3963 * In the presence of smp nice balancing, certain scenarios can have
3964 * max load less than avg load(as we skip the groups at or below
3965 * its cpu_power, while calculating max_load..)
3967 if (sds
->max_load
< sds
->avg_load
) {
3969 return fix_small_imbalance(sds
, this_cpu
, imbalance
);
3972 /* Don't want to pull so many tasks that a group would go idle */
3973 max_pull
= min(sds
->max_load
- sds
->avg_load
,
3974 sds
->max_load
- sds
->busiest_load_per_task
);
3976 /* How much load to actually move to equalise the imbalance */
3977 *imbalance
= min(max_pull
* sds
->busiest
->cpu_power
,
3978 (sds
->avg_load
- sds
->this_load
) * sds
->this->cpu_power
)
3982 * if *imbalance is less than the average load per runnable task
3983 * there is no gaurantee that any tasks will be moved so we'll have
3984 * a think about bumping its value to force at least one task to be
3987 if (*imbalance
< sds
->busiest_load_per_task
)
3988 return fix_small_imbalance(sds
, this_cpu
, imbalance
);
3991 /******* find_busiest_group() helpers end here *********************/
3994 * find_busiest_group - Returns the busiest group within the sched_domain
3995 * if there is an imbalance. If there isn't an imbalance, and
3996 * the user has opted for power-savings, it returns a group whose
3997 * CPUs can be put to idle by rebalancing those tasks elsewhere, if
3998 * such a group exists.
4000 * Also calculates the amount of weighted load which should be moved
4001 * to restore balance.
4003 * @sd: The sched_domain whose busiest group is to be returned.
4004 * @this_cpu: The cpu for which load balancing is currently being performed.
4005 * @imbalance: Variable which stores amount of weighted load which should
4006 * be moved to restore balance/put a group to idle.
4007 * @idle: The idle status of this_cpu.
4008 * @sd_idle: The idleness of sd
4009 * @cpus: The set of CPUs under consideration for load-balancing.
4010 * @balance: Pointer to a variable indicating if this_cpu
4011 * is the appropriate cpu to perform load balancing at this_level.
4013 * Returns: - the busiest group if imbalance exists.
4014 * - If no imbalance and user has opted for power-savings balance,
4015 * return the least loaded group whose CPUs can be
4016 * put to idle by rebalancing its tasks onto our group.
4018 static struct sched_group
*
4019 find_busiest_group(struct sched_domain
*sd
, int this_cpu
,
4020 unsigned long *imbalance
, enum cpu_idle_type idle
,
4021 int *sd_idle
, const struct cpumask
*cpus
, int *balance
)
4023 struct sd_lb_stats sds
;
4025 memset(&sds
, 0, sizeof(sds
));
4028 * Compute the various statistics relavent for load balancing at
4031 update_sd_lb_stats(sd
, this_cpu
, idle
, sd_idle
, cpus
,
4034 /* Cases where imbalance does not exist from POV of this_cpu */
4035 /* 1) this_cpu is not the appropriate cpu to perform load balancing
4037 * 2) There is no busy sibling group to pull from.
4038 * 3) This group is the busiest group.
4039 * 4) This group is more busy than the avg busieness at this
4041 * 5) The imbalance is within the specified limit.
4042 * 6) Any rebalance would lead to ping-pong
4044 if (balance
&& !(*balance
))
4047 if (!sds
.busiest
|| sds
.busiest_nr_running
== 0)
4050 if (sds
.this_load
>= sds
.max_load
)
4053 sds
.avg_load
= (SCHED_LOAD_SCALE
* sds
.total_load
) / sds
.total_pwr
;
4055 if (sds
.this_load
>= sds
.avg_load
)
4058 if (100 * sds
.max_load
<= sd
->imbalance_pct
* sds
.this_load
)
4061 sds
.busiest_load_per_task
/= sds
.busiest_nr_running
;
4063 sds
.busiest_load_per_task
=
4064 min(sds
.busiest_load_per_task
, sds
.avg_load
);
4067 * We're trying to get all the cpus to the average_load, so we don't
4068 * want to push ourselves above the average load, nor do we wish to
4069 * reduce the max loaded cpu below the average load, as either of these
4070 * actions would just result in more rebalancing later, and ping-pong
4071 * tasks around. Thus we look for the minimum possible imbalance.
4072 * Negative imbalances (*we* are more loaded than anyone else) will
4073 * be counted as no imbalance for these purposes -- we can't fix that
4074 * by pulling tasks to us. Be careful of negative numbers as they'll
4075 * appear as very large values with unsigned longs.
4077 if (sds
.max_load
<= sds
.busiest_load_per_task
)
4080 /* Looks like there is an imbalance. Compute it */
4081 calculate_imbalance(&sds
, this_cpu
, imbalance
);
4086 * There is no obvious imbalance. But check if we can do some balancing
4089 if (check_power_save_busiest_group(&sds
, this_cpu
, imbalance
))
4097 * find_busiest_queue - find the busiest runqueue among the cpus in group.
4100 find_busiest_queue(struct sched_group
*group
, enum cpu_idle_type idle
,
4101 unsigned long imbalance
, const struct cpumask
*cpus
)
4103 struct rq
*busiest
= NULL
, *rq
;
4104 unsigned long max_load
= 0;
4107 for_each_cpu(i
, sched_group_cpus(group
)) {
4108 unsigned long power
= power_of(i
);
4109 unsigned long capacity
= DIV_ROUND_CLOSEST(power
, SCHED_LOAD_SCALE
);
4112 if (!cpumask_test_cpu(i
, cpus
))
4116 wl
= weighted_cpuload(i
) * SCHED_LOAD_SCALE
;
4119 if (capacity
&& rq
->nr_running
== 1 && wl
> imbalance
)
4122 if (wl
> max_load
) {
4132 * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but
4133 * so long as it is large enough.
4135 #define MAX_PINNED_INTERVAL 512
4137 /* Working cpumask for load_balance and load_balance_newidle. */
4138 static DEFINE_PER_CPU(cpumask_var_t
, load_balance_tmpmask
);
4141 * Check this_cpu to ensure it is balanced within domain. Attempt to move
4142 * tasks if there is an imbalance.
4144 static int load_balance(int this_cpu
, struct rq
*this_rq
,
4145 struct sched_domain
*sd
, enum cpu_idle_type idle
,
4148 int ld_moved
, all_pinned
= 0, active_balance
= 0, sd_idle
= 0;
4149 struct sched_group
*group
;
4150 unsigned long imbalance
;
4152 unsigned long flags
;
4153 struct cpumask
*cpus
= __get_cpu_var(load_balance_tmpmask
);
4155 cpumask_copy(cpus
, cpu_active_mask
);
4158 * When power savings policy is enabled for the parent domain, idle
4159 * sibling can pick up load irrespective of busy siblings. In this case,
4160 * let the state of idle sibling percolate up as CPU_IDLE, instead of
4161 * portraying it as CPU_NOT_IDLE.
4163 if (idle
!= CPU_NOT_IDLE
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
4164 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
4167 schedstat_inc(sd
, lb_count
[idle
]);
4171 group
= find_busiest_group(sd
, this_cpu
, &imbalance
, idle
, &sd_idle
,
4178 schedstat_inc(sd
, lb_nobusyg
[idle
]);
4182 busiest
= find_busiest_queue(group
, idle
, imbalance
, cpus
);
4184 schedstat_inc(sd
, lb_nobusyq
[idle
]);
4188 BUG_ON(busiest
== this_rq
);
4190 schedstat_add(sd
, lb_imbalance
[idle
], imbalance
);
4193 if (busiest
->nr_running
> 1) {
4195 * Attempt to move tasks. If find_busiest_group has found
4196 * an imbalance but busiest->nr_running <= 1, the group is
4197 * still unbalanced. ld_moved simply stays zero, so it is
4198 * correctly treated as an imbalance.
4200 local_irq_save(flags
);
4201 double_rq_lock(this_rq
, busiest
);
4202 ld_moved
= move_tasks(this_rq
, this_cpu
, busiest
,
4203 imbalance
, sd
, idle
, &all_pinned
);
4204 double_rq_unlock(this_rq
, busiest
);
4205 local_irq_restore(flags
);
4208 * some other cpu did the load balance for us.
4210 if (ld_moved
&& this_cpu
!= smp_processor_id())
4211 resched_cpu(this_cpu
);
4213 /* All tasks on this runqueue were pinned by CPU affinity */
4214 if (unlikely(all_pinned
)) {
4215 cpumask_clear_cpu(cpu_of(busiest
), cpus
);
4216 if (!cpumask_empty(cpus
))
4223 schedstat_inc(sd
, lb_failed
[idle
]);
4224 sd
->nr_balance_failed
++;
4226 if (unlikely(sd
->nr_balance_failed
> sd
->cache_nice_tries
+2)) {
4228 raw_spin_lock_irqsave(&busiest
->lock
, flags
);
4230 /* don't kick the migration_thread, if the curr
4231 * task on busiest cpu can't be moved to this_cpu
4233 if (!cpumask_test_cpu(this_cpu
,
4234 &busiest
->curr
->cpus_allowed
)) {
4235 raw_spin_unlock_irqrestore(&busiest
->lock
,
4238 goto out_one_pinned
;
4241 if (!busiest
->active_balance
) {
4242 busiest
->active_balance
= 1;
4243 busiest
->push_cpu
= this_cpu
;
4246 raw_spin_unlock_irqrestore(&busiest
->lock
, flags
);
4248 wake_up_process(busiest
->migration_thread
);
4251 * We've kicked active balancing, reset the failure
4254 sd
->nr_balance_failed
= sd
->cache_nice_tries
+1;
4257 sd
->nr_balance_failed
= 0;
4259 if (likely(!active_balance
)) {
4260 /* We were unbalanced, so reset the balancing interval */
4261 sd
->balance_interval
= sd
->min_interval
;
4264 * If we've begun active balancing, start to back off. This
4265 * case may not be covered by the all_pinned logic if there
4266 * is only 1 task on the busy runqueue (because we don't call
4269 if (sd
->balance_interval
< sd
->max_interval
)
4270 sd
->balance_interval
*= 2;
4273 if (!ld_moved
&& !sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
4274 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
4280 schedstat_inc(sd
, lb_balanced
[idle
]);
4282 sd
->nr_balance_failed
= 0;
4285 /* tune up the balancing interval */
4286 if ((all_pinned
&& sd
->balance_interval
< MAX_PINNED_INTERVAL
) ||
4287 (sd
->balance_interval
< sd
->max_interval
))
4288 sd
->balance_interval
*= 2;
4290 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
4291 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
4302 * Check this_cpu to ensure it is balanced within domain. Attempt to move
4303 * tasks if there is an imbalance.
4305 * Called from schedule when this_rq is about to become idle (CPU_NEWLY_IDLE).
4306 * this_rq is locked.
4309 load_balance_newidle(int this_cpu
, struct rq
*this_rq
, struct sched_domain
*sd
)
4311 struct sched_group
*group
;
4312 struct rq
*busiest
= NULL
;
4313 unsigned long imbalance
;
4317 struct cpumask
*cpus
= __get_cpu_var(load_balance_tmpmask
);
4319 cpumask_copy(cpus
, cpu_active_mask
);
4322 * When power savings policy is enabled for the parent domain, idle
4323 * sibling can pick up load irrespective of busy siblings. In this case,
4324 * let the state of idle sibling percolate up as IDLE, instead of
4325 * portraying it as CPU_NOT_IDLE.
4327 if (sd
->flags
& SD_SHARE_CPUPOWER
&&
4328 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
4331 schedstat_inc(sd
, lb_count
[CPU_NEWLY_IDLE
]);
4333 update_shares_locked(this_rq
, sd
);
4334 group
= find_busiest_group(sd
, this_cpu
, &imbalance
, CPU_NEWLY_IDLE
,
4335 &sd_idle
, cpus
, NULL
);
4337 schedstat_inc(sd
, lb_nobusyg
[CPU_NEWLY_IDLE
]);
4341 busiest
= find_busiest_queue(group
, CPU_NEWLY_IDLE
, imbalance
, cpus
);
4343 schedstat_inc(sd
, lb_nobusyq
[CPU_NEWLY_IDLE
]);
4347 BUG_ON(busiest
== this_rq
);
4349 schedstat_add(sd
, lb_imbalance
[CPU_NEWLY_IDLE
], imbalance
);
4352 if (busiest
->nr_running
> 1) {
4353 /* Attempt to move tasks */
4354 double_lock_balance(this_rq
, busiest
);
4355 /* this_rq->clock is already updated */
4356 update_rq_clock(busiest
);
4357 ld_moved
= move_tasks(this_rq
, this_cpu
, busiest
,
4358 imbalance
, sd
, CPU_NEWLY_IDLE
,
4360 double_unlock_balance(this_rq
, busiest
);
4362 if (unlikely(all_pinned
)) {
4363 cpumask_clear_cpu(cpu_of(busiest
), cpus
);
4364 if (!cpumask_empty(cpus
))
4370 int active_balance
= 0;
4372 schedstat_inc(sd
, lb_failed
[CPU_NEWLY_IDLE
]);
4373 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
4374 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
4377 if (sched_mc_power_savings
< POWERSAVINGS_BALANCE_WAKEUP
)
4380 if (sd
->nr_balance_failed
++ < 2)
4384 * The only task running in a non-idle cpu can be moved to this
4385 * cpu in an attempt to completely freeup the other CPU
4386 * package. The same method used to move task in load_balance()
4387 * have been extended for load_balance_newidle() to speedup
4388 * consolidation at sched_mc=POWERSAVINGS_BALANCE_WAKEUP (2)
4390 * The package power saving logic comes from
4391 * find_busiest_group(). If there are no imbalance, then
4392 * f_b_g() will return NULL. However when sched_mc={1,2} then
4393 * f_b_g() will select a group from which a running task may be
4394 * pulled to this cpu in order to make the other package idle.
4395 * If there is no opportunity to make a package idle and if
4396 * there are no imbalance, then f_b_g() will return NULL and no
4397 * action will be taken in load_balance_newidle().
4399 * Under normal task pull operation due to imbalance, there
4400 * will be more than one task in the source run queue and
4401 * move_tasks() will succeed. ld_moved will be true and this
4402 * active balance code will not be triggered.
4405 /* Lock busiest in correct order while this_rq is held */
4406 double_lock_balance(this_rq
, busiest
);
4409 * don't kick the migration_thread, if the curr
4410 * task on busiest cpu can't be moved to this_cpu
4412 if (!cpumask_test_cpu(this_cpu
, &busiest
->curr
->cpus_allowed
)) {
4413 double_unlock_balance(this_rq
, busiest
);
4418 if (!busiest
->active_balance
) {
4419 busiest
->active_balance
= 1;
4420 busiest
->push_cpu
= this_cpu
;
4424 double_unlock_balance(this_rq
, busiest
);
4426 * Should not call ttwu while holding a rq->lock
4428 raw_spin_unlock(&this_rq
->lock
);
4430 wake_up_process(busiest
->migration_thread
);
4431 raw_spin_lock(&this_rq
->lock
);
4434 sd
->nr_balance_failed
= 0;
4436 update_shares_locked(this_rq
, sd
);
4440 schedstat_inc(sd
, lb_balanced
[CPU_NEWLY_IDLE
]);
4441 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
4442 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
4444 sd
->nr_balance_failed
= 0;
4450 * idle_balance is called by schedule() if this_cpu is about to become
4451 * idle. Attempts to pull tasks from other CPUs.
4453 static void idle_balance(int this_cpu
, struct rq
*this_rq
)
4455 struct sched_domain
*sd
;
4456 int pulled_task
= 0;
4457 unsigned long next_balance
= jiffies
+ HZ
;
4459 this_rq
->idle_stamp
= this_rq
->clock
;
4461 if (this_rq
->avg_idle
< sysctl_sched_migration_cost
)
4464 for_each_domain(this_cpu
, sd
) {
4465 unsigned long interval
;
4467 if (!(sd
->flags
& SD_LOAD_BALANCE
))
4470 if (sd
->flags
& SD_BALANCE_NEWIDLE
)
4471 /* If we've pulled tasks over stop searching: */
4472 pulled_task
= load_balance_newidle(this_cpu
, this_rq
,
4475 interval
= msecs_to_jiffies(sd
->balance_interval
);
4476 if (time_after(next_balance
, sd
->last_balance
+ interval
))
4477 next_balance
= sd
->last_balance
+ interval
;
4479 this_rq
->idle_stamp
= 0;
4483 if (pulled_task
|| time_after(jiffies
, this_rq
->next_balance
)) {
4485 * We are going idle. next_balance may be set based on
4486 * a busy processor. So reset next_balance.
4488 this_rq
->next_balance
= next_balance
;
4493 * active_load_balance is run by migration threads. It pushes running tasks
4494 * off the busiest CPU onto idle CPUs. It requires at least 1 task to be
4495 * running on each physical CPU where possible, and avoids physical /
4496 * logical imbalances.
4498 * Called with busiest_rq locked.
4500 static void active_load_balance(struct rq
*busiest_rq
, int busiest_cpu
)
4502 int target_cpu
= busiest_rq
->push_cpu
;
4503 struct sched_domain
*sd
;
4504 struct rq
*target_rq
;
4506 /* Is there any task to move? */
4507 if (busiest_rq
->nr_running
<= 1)
4510 target_rq
= cpu_rq(target_cpu
);
4513 * This condition is "impossible", if it occurs
4514 * we need to fix it. Originally reported by
4515 * Bjorn Helgaas on a 128-cpu setup.
4517 BUG_ON(busiest_rq
== target_rq
);
4519 /* move a task from busiest_rq to target_rq */
4520 double_lock_balance(busiest_rq
, target_rq
);
4521 update_rq_clock(busiest_rq
);
4522 update_rq_clock(target_rq
);
4524 /* Search for an sd spanning us and the target CPU. */
4525 for_each_domain(target_cpu
, sd
) {
4526 if ((sd
->flags
& SD_LOAD_BALANCE
) &&
4527 cpumask_test_cpu(busiest_cpu
, sched_domain_span(sd
)))
4532 schedstat_inc(sd
, alb_count
);
4534 if (move_one_task(target_rq
, target_cpu
, busiest_rq
,
4536 schedstat_inc(sd
, alb_pushed
);
4538 schedstat_inc(sd
, alb_failed
);
4540 double_unlock_balance(busiest_rq
, target_rq
);
4545 atomic_t load_balancer
;
4546 cpumask_var_t cpu_mask
;
4547 cpumask_var_t ilb_grp_nohz_mask
;
4548 } nohz ____cacheline_aligned
= {
4549 .load_balancer
= ATOMIC_INIT(-1),
4552 int get_nohz_load_balancer(void)
4554 return atomic_read(&nohz
.load_balancer
);
4557 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
4559 * lowest_flag_domain - Return lowest sched_domain containing flag.
4560 * @cpu: The cpu whose lowest level of sched domain is to
4562 * @flag: The flag to check for the lowest sched_domain
4563 * for the given cpu.
4565 * Returns the lowest sched_domain of a cpu which contains the given flag.
4567 static inline struct sched_domain
*lowest_flag_domain(int cpu
, int flag
)
4569 struct sched_domain
*sd
;
4571 for_each_domain(cpu
, sd
)
4572 if (sd
&& (sd
->flags
& flag
))
4579 * for_each_flag_domain - Iterates over sched_domains containing the flag.
4580 * @cpu: The cpu whose domains we're iterating over.
4581 * @sd: variable holding the value of the power_savings_sd
4583 * @flag: The flag to filter the sched_domains to be iterated.
4585 * Iterates over all the scheduler domains for a given cpu that has the 'flag'
4586 * set, starting from the lowest sched_domain to the highest.
4588 #define for_each_flag_domain(cpu, sd, flag) \
4589 for (sd = lowest_flag_domain(cpu, flag); \
4590 (sd && (sd->flags & flag)); sd = sd->parent)
4593 * is_semi_idle_group - Checks if the given sched_group is semi-idle.
4594 * @ilb_group: group to be checked for semi-idleness
4596 * Returns: 1 if the group is semi-idle. 0 otherwise.
4598 * We define a sched_group to be semi idle if it has atleast one idle-CPU
4599 * and atleast one non-idle CPU. This helper function checks if the given
4600 * sched_group is semi-idle or not.
4602 static inline int is_semi_idle_group(struct sched_group
*ilb_group
)
4604 cpumask_and(nohz
.ilb_grp_nohz_mask
, nohz
.cpu_mask
,
4605 sched_group_cpus(ilb_group
));
4608 * A sched_group is semi-idle when it has atleast one busy cpu
4609 * and atleast one idle cpu.
4611 if (cpumask_empty(nohz
.ilb_grp_nohz_mask
))
4614 if (cpumask_equal(nohz
.ilb_grp_nohz_mask
, sched_group_cpus(ilb_group
)))
4620 * find_new_ilb - Finds the optimum idle load balancer for nomination.
4621 * @cpu: The cpu which is nominating a new idle_load_balancer.
4623 * Returns: Returns the id of the idle load balancer if it exists,
4624 * Else, returns >= nr_cpu_ids.
4626 * This algorithm picks the idle load balancer such that it belongs to a
4627 * semi-idle powersavings sched_domain. The idea is to try and avoid
4628 * completely idle packages/cores just for the purpose of idle load balancing
4629 * when there are other idle cpu's which are better suited for that job.
4631 static int find_new_ilb(int cpu
)
4633 struct sched_domain
*sd
;
4634 struct sched_group
*ilb_group
;
4637 * Have idle load balancer selection from semi-idle packages only
4638 * when power-aware load balancing is enabled
4640 if (!(sched_smt_power_savings
|| sched_mc_power_savings
))
4644 * Optimize for the case when we have no idle CPUs or only one
4645 * idle CPU. Don't walk the sched_domain hierarchy in such cases
4647 if (cpumask_weight(nohz
.cpu_mask
) < 2)
4650 for_each_flag_domain(cpu
, sd
, SD_POWERSAVINGS_BALANCE
) {
4651 ilb_group
= sd
->groups
;
4654 if (is_semi_idle_group(ilb_group
))
4655 return cpumask_first(nohz
.ilb_grp_nohz_mask
);
4657 ilb_group
= ilb_group
->next
;
4659 } while (ilb_group
!= sd
->groups
);
4663 return cpumask_first(nohz
.cpu_mask
);
4665 #else /* (CONFIG_SCHED_MC || CONFIG_SCHED_SMT) */
4666 static inline int find_new_ilb(int call_cpu
)
4668 return cpumask_first(nohz
.cpu_mask
);
4673 * This routine will try to nominate the ilb (idle load balancing)
4674 * owner among the cpus whose ticks are stopped. ilb owner will do the idle
4675 * load balancing on behalf of all those cpus. If all the cpus in the system
4676 * go into this tickless mode, then there will be no ilb owner (as there is
4677 * no need for one) and all the cpus will sleep till the next wakeup event
4680 * For the ilb owner, tick is not stopped. And this tick will be used
4681 * for idle load balancing. ilb owner will still be part of
4684 * While stopping the tick, this cpu will become the ilb owner if there
4685 * is no other owner. And will be the owner till that cpu becomes busy
4686 * or if all cpus in the system stop their ticks at which point
4687 * there is no need for ilb owner.
4689 * When the ilb owner becomes busy, it nominates another owner, during the
4690 * next busy scheduler_tick()
4692 int select_nohz_load_balancer(int stop_tick
)
4694 int cpu
= smp_processor_id();
4697 cpu_rq(cpu
)->in_nohz_recently
= 1;
4699 if (!cpu_active(cpu
)) {
4700 if (atomic_read(&nohz
.load_balancer
) != cpu
)
4704 * If we are going offline and still the leader,
4707 if (atomic_cmpxchg(&nohz
.load_balancer
, cpu
, -1) != cpu
)
4713 cpumask_set_cpu(cpu
, nohz
.cpu_mask
);
4715 /* time for ilb owner also to sleep */
4716 if (cpumask_weight(nohz
.cpu_mask
) == num_active_cpus()) {
4717 if (atomic_read(&nohz
.load_balancer
) == cpu
)
4718 atomic_set(&nohz
.load_balancer
, -1);
4722 if (atomic_read(&nohz
.load_balancer
) == -1) {
4723 /* make me the ilb owner */
4724 if (atomic_cmpxchg(&nohz
.load_balancer
, -1, cpu
) == -1)
4726 } else if (atomic_read(&nohz
.load_balancer
) == cpu
) {
4729 if (!(sched_smt_power_savings
||
4730 sched_mc_power_savings
))
4733 * Check to see if there is a more power-efficient
4736 new_ilb
= find_new_ilb(cpu
);
4737 if (new_ilb
< nr_cpu_ids
&& new_ilb
!= cpu
) {
4738 atomic_set(&nohz
.load_balancer
, -1);
4739 resched_cpu(new_ilb
);
4745 if (!cpumask_test_cpu(cpu
, nohz
.cpu_mask
))
4748 cpumask_clear_cpu(cpu
, nohz
.cpu_mask
);
4750 if (atomic_read(&nohz
.load_balancer
) == cpu
)
4751 if (atomic_cmpxchg(&nohz
.load_balancer
, cpu
, -1) != cpu
)
4758 static DEFINE_SPINLOCK(balancing
);
4761 * It checks each scheduling domain to see if it is due to be balanced,
4762 * and initiates a balancing operation if so.
4764 * Balancing parameters are set up in arch_init_sched_domains.
4766 static void rebalance_domains(int cpu
, enum cpu_idle_type idle
)
4769 struct rq
*rq
= cpu_rq(cpu
);
4770 unsigned long interval
;
4771 struct sched_domain
*sd
;
4772 /* Earliest time when we have to do rebalance again */
4773 unsigned long next_balance
= jiffies
+ 60*HZ
;
4774 int update_next_balance
= 0;
4777 for_each_domain(cpu
, sd
) {
4778 if (!(sd
->flags
& SD_LOAD_BALANCE
))
4781 interval
= sd
->balance_interval
;
4782 if (idle
!= CPU_IDLE
)
4783 interval
*= sd
->busy_factor
;
4785 /* scale ms to jiffies */
4786 interval
= msecs_to_jiffies(interval
);
4787 if (unlikely(!interval
))
4789 if (interval
> HZ
*NR_CPUS
/10)
4790 interval
= HZ
*NR_CPUS
/10;
4792 need_serialize
= sd
->flags
& SD_SERIALIZE
;
4794 if (need_serialize
) {
4795 if (!spin_trylock(&balancing
))
4799 if (time_after_eq(jiffies
, sd
->last_balance
+ interval
)) {
4800 if (load_balance(cpu
, rq
, sd
, idle
, &balance
)) {
4802 * We've pulled tasks over so either we're no
4803 * longer idle, or one of our SMT siblings is
4806 idle
= CPU_NOT_IDLE
;
4808 sd
->last_balance
= jiffies
;
4811 spin_unlock(&balancing
);
4813 if (time_after(next_balance
, sd
->last_balance
+ interval
)) {
4814 next_balance
= sd
->last_balance
+ interval
;
4815 update_next_balance
= 1;
4819 * Stop the load balance at this level. There is another
4820 * CPU in our sched group which is doing load balancing more
4828 * next_balance will be updated only when there is a need.
4829 * When the cpu is attached to null domain for ex, it will not be
4832 if (likely(update_next_balance
))
4833 rq
->next_balance
= next_balance
;
4837 * run_rebalance_domains is triggered when needed from the scheduler tick.
4838 * In CONFIG_NO_HZ case, the idle load balance owner will do the
4839 * rebalancing for all the cpus for whom scheduler ticks are stopped.
4841 static void run_rebalance_domains(struct softirq_action
*h
)
4843 int this_cpu
= smp_processor_id();
4844 struct rq
*this_rq
= cpu_rq(this_cpu
);
4845 enum cpu_idle_type idle
= this_rq
->idle_at_tick
?
4846 CPU_IDLE
: CPU_NOT_IDLE
;
4848 rebalance_domains(this_cpu
, idle
);
4852 * If this cpu is the owner for idle load balancing, then do the
4853 * balancing on behalf of the other idle cpus whose ticks are
4856 if (this_rq
->idle_at_tick
&&
4857 atomic_read(&nohz
.load_balancer
) == this_cpu
) {
4861 for_each_cpu(balance_cpu
, nohz
.cpu_mask
) {
4862 if (balance_cpu
== this_cpu
)
4866 * If this cpu gets work to do, stop the load balancing
4867 * work being done for other cpus. Next load
4868 * balancing owner will pick it up.
4873 rebalance_domains(balance_cpu
, CPU_IDLE
);
4875 rq
= cpu_rq(balance_cpu
);
4876 if (time_after(this_rq
->next_balance
, rq
->next_balance
))
4877 this_rq
->next_balance
= rq
->next_balance
;
4883 static inline int on_null_domain(int cpu
)
4885 return !rcu_dereference(cpu_rq(cpu
)->sd
);
4889 * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing.
4891 * In case of CONFIG_NO_HZ, this is the place where we nominate a new
4892 * idle load balancing owner or decide to stop the periodic load balancing,
4893 * if the whole system is idle.
4895 static inline void trigger_load_balance(struct rq
*rq
, int cpu
)
4899 * If we were in the nohz mode recently and busy at the current
4900 * scheduler tick, then check if we need to nominate new idle
4903 if (rq
->in_nohz_recently
&& !rq
->idle_at_tick
) {
4904 rq
->in_nohz_recently
= 0;
4906 if (atomic_read(&nohz
.load_balancer
) == cpu
) {
4907 cpumask_clear_cpu(cpu
, nohz
.cpu_mask
);
4908 atomic_set(&nohz
.load_balancer
, -1);
4911 if (atomic_read(&nohz
.load_balancer
) == -1) {
4912 int ilb
= find_new_ilb(cpu
);
4914 if (ilb
< nr_cpu_ids
)
4920 * If this cpu is idle and doing idle load balancing for all the
4921 * cpus with ticks stopped, is it time for that to stop?
4923 if (rq
->idle_at_tick
&& atomic_read(&nohz
.load_balancer
) == cpu
&&
4924 cpumask_weight(nohz
.cpu_mask
) == num_online_cpus()) {
4930 * If this cpu is idle and the idle load balancing is done by
4931 * someone else, then no need raise the SCHED_SOFTIRQ
4933 if (rq
->idle_at_tick
&& atomic_read(&nohz
.load_balancer
) != cpu
&&
4934 cpumask_test_cpu(cpu
, nohz
.cpu_mask
))
4937 /* Don't need to rebalance while attached to NULL domain */
4938 if (time_after_eq(jiffies
, rq
->next_balance
) &&
4939 likely(!on_null_domain(cpu
)))
4940 raise_softirq(SCHED_SOFTIRQ
);
4943 #else /* CONFIG_SMP */
4946 * on UP we do not need to balance between CPUs:
4948 static inline void idle_balance(int cpu
, struct rq
*rq
)
4954 DEFINE_PER_CPU(struct kernel_stat
, kstat
);
4956 EXPORT_PER_CPU_SYMBOL(kstat
);
4959 * Return any ns on the sched_clock that have not yet been accounted in
4960 * @p in case that task is currently running.
4962 * Called with task_rq_lock() held on @rq.
4964 static u64
do_task_delta_exec(struct task_struct
*p
, struct rq
*rq
)
4968 if (task_current(rq
, p
)) {
4969 update_rq_clock(rq
);
4970 ns
= rq
->clock
- p
->se
.exec_start
;
4978 unsigned long long task_delta_exec(struct task_struct
*p
)
4980 unsigned long flags
;
4984 rq
= task_rq_lock(p
, &flags
);
4985 ns
= do_task_delta_exec(p
, rq
);
4986 task_rq_unlock(rq
, &flags
);
4992 * Return accounted runtime for the task.
4993 * In case the task is currently running, return the runtime plus current's
4994 * pending runtime that have not been accounted yet.
4996 unsigned long long task_sched_runtime(struct task_struct
*p
)
4998 unsigned long flags
;
5002 rq
= task_rq_lock(p
, &flags
);
5003 ns
= p
->se
.sum_exec_runtime
+ do_task_delta_exec(p
, rq
);
5004 task_rq_unlock(rq
, &flags
);
5010 * Return sum_exec_runtime for the thread group.
5011 * In case the task is currently running, return the sum plus current's
5012 * pending runtime that have not been accounted yet.
5014 * Note that the thread group might have other running tasks as well,
5015 * so the return value not includes other pending runtime that other
5016 * running tasks might have.
5018 unsigned long long thread_group_sched_runtime(struct task_struct
*p
)
5020 struct task_cputime totals
;
5021 unsigned long flags
;
5025 rq
= task_rq_lock(p
, &flags
);
5026 thread_group_cputime(p
, &totals
);
5027 ns
= totals
.sum_exec_runtime
+ do_task_delta_exec(p
, rq
);
5028 task_rq_unlock(rq
, &flags
);
5034 * Account user cpu time to a process.
5035 * @p: the process that the cpu time gets accounted to
5036 * @cputime: the cpu time spent in user space since the last update
5037 * @cputime_scaled: cputime scaled by cpu frequency
5039 void account_user_time(struct task_struct
*p
, cputime_t cputime
,
5040 cputime_t cputime_scaled
)
5042 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
5045 /* Add user time to process. */
5046 p
->utime
= cputime_add(p
->utime
, cputime
);
5047 p
->utimescaled
= cputime_add(p
->utimescaled
, cputime_scaled
);
5048 account_group_user_time(p
, cputime
);
5050 /* Add user time to cpustat. */
5051 tmp
= cputime_to_cputime64(cputime
);
5052 if (TASK_NICE(p
) > 0)
5053 cpustat
->nice
= cputime64_add(cpustat
->nice
, tmp
);
5055 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
5057 cpuacct_update_stats(p
, CPUACCT_STAT_USER
, cputime
);
5058 /* Account for user time used */
5059 acct_update_integrals(p
);
5063 * Account guest cpu time to a process.
5064 * @p: the process that the cpu time gets accounted to
5065 * @cputime: the cpu time spent in virtual machine since the last update
5066 * @cputime_scaled: cputime scaled by cpu frequency
5068 static void account_guest_time(struct task_struct
*p
, cputime_t cputime
,
5069 cputime_t cputime_scaled
)
5072 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
5074 tmp
= cputime_to_cputime64(cputime
);
5076 /* Add guest time to process. */
5077 p
->utime
= cputime_add(p
->utime
, cputime
);
5078 p
->utimescaled
= cputime_add(p
->utimescaled
, cputime_scaled
);
5079 account_group_user_time(p
, cputime
);
5080 p
->gtime
= cputime_add(p
->gtime
, cputime
);
5082 /* Add guest time to cpustat. */
5083 if (TASK_NICE(p
) > 0) {
5084 cpustat
->nice
= cputime64_add(cpustat
->nice
, tmp
);
5085 cpustat
->guest_nice
= cputime64_add(cpustat
->guest_nice
, tmp
);
5087 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
5088 cpustat
->guest
= cputime64_add(cpustat
->guest
, tmp
);
5093 * Account system cpu time to a process.
5094 * @p: the process that the cpu time gets accounted to
5095 * @hardirq_offset: the offset to subtract from hardirq_count()
5096 * @cputime: the cpu time spent in kernel space since the last update
5097 * @cputime_scaled: cputime scaled by cpu frequency
5099 void account_system_time(struct task_struct
*p
, int hardirq_offset
,
5100 cputime_t cputime
, cputime_t cputime_scaled
)
5102 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
5105 if ((p
->flags
& PF_VCPU
) && (irq_count() - hardirq_offset
== 0)) {
5106 account_guest_time(p
, cputime
, cputime_scaled
);
5110 /* Add system time to process. */
5111 p
->stime
= cputime_add(p
->stime
, cputime
);
5112 p
->stimescaled
= cputime_add(p
->stimescaled
, cputime_scaled
);
5113 account_group_system_time(p
, cputime
);
5115 /* Add system time to cpustat. */
5116 tmp
= cputime_to_cputime64(cputime
);
5117 if (hardirq_count() - hardirq_offset
)
5118 cpustat
->irq
= cputime64_add(cpustat
->irq
, tmp
);
5119 else if (softirq_count())
5120 cpustat
->softirq
= cputime64_add(cpustat
->softirq
, tmp
);
5122 cpustat
->system
= cputime64_add(cpustat
->system
, tmp
);
5124 cpuacct_update_stats(p
, CPUACCT_STAT_SYSTEM
, cputime
);
5126 /* Account for system time used */
5127 acct_update_integrals(p
);
5131 * Account for involuntary wait time.
5132 * @steal: the cpu time spent in involuntary wait
5134 void account_steal_time(cputime_t cputime
)
5136 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
5137 cputime64_t cputime64
= cputime_to_cputime64(cputime
);
5139 cpustat
->steal
= cputime64_add(cpustat
->steal
, cputime64
);
5143 * Account for idle time.
5144 * @cputime: the cpu time spent in idle wait
5146 void account_idle_time(cputime_t cputime
)
5148 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
5149 cputime64_t cputime64
= cputime_to_cputime64(cputime
);
5150 struct rq
*rq
= this_rq();
5152 if (atomic_read(&rq
->nr_iowait
) > 0)
5153 cpustat
->iowait
= cputime64_add(cpustat
->iowait
, cputime64
);
5155 cpustat
->idle
= cputime64_add(cpustat
->idle
, cputime64
);
5158 #ifndef CONFIG_VIRT_CPU_ACCOUNTING
5161 * Account a single tick of cpu time.
5162 * @p: the process that the cpu time gets accounted to
5163 * @user_tick: indicates if the tick is a user or a system tick
5165 void account_process_tick(struct task_struct
*p
, int user_tick
)
5167 cputime_t one_jiffy_scaled
= cputime_to_scaled(cputime_one_jiffy
);
5168 struct rq
*rq
= this_rq();
5171 account_user_time(p
, cputime_one_jiffy
, one_jiffy_scaled
);
5172 else if ((p
!= rq
->idle
) || (irq_count() != HARDIRQ_OFFSET
))
5173 account_system_time(p
, HARDIRQ_OFFSET
, cputime_one_jiffy
,
5176 account_idle_time(cputime_one_jiffy
);
5180 * Account multiple ticks of steal time.
5181 * @p: the process from which the cpu time has been stolen
5182 * @ticks: number of stolen ticks
5184 void account_steal_ticks(unsigned long ticks
)
5186 account_steal_time(jiffies_to_cputime(ticks
));
5190 * Account multiple ticks of idle time.
5191 * @ticks: number of stolen ticks
5193 void account_idle_ticks(unsigned long ticks
)
5195 account_idle_time(jiffies_to_cputime(ticks
));
5201 * Use precise platform statistics if available:
5203 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
5204 void task_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
5210 void thread_group_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
5212 struct task_cputime cputime
;
5214 thread_group_cputime(p
, &cputime
);
5216 *ut
= cputime
.utime
;
5217 *st
= cputime
.stime
;
5221 #ifndef nsecs_to_cputime
5222 # define nsecs_to_cputime(__nsecs) nsecs_to_jiffies(__nsecs)
5225 void task_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
5227 cputime_t rtime
, utime
= p
->utime
, total
= cputime_add(utime
, p
->stime
);
5230 * Use CFS's precise accounting:
5232 rtime
= nsecs_to_cputime(p
->se
.sum_exec_runtime
);
5237 temp
= (u64
)(rtime
* utime
);
5238 do_div(temp
, total
);
5239 utime
= (cputime_t
)temp
;
5244 * Compare with previous values, to keep monotonicity:
5246 p
->prev_utime
= max(p
->prev_utime
, utime
);
5247 p
->prev_stime
= max(p
->prev_stime
, cputime_sub(rtime
, p
->prev_utime
));
5249 *ut
= p
->prev_utime
;
5250 *st
= p
->prev_stime
;
5254 * Must be called with siglock held.
5256 void thread_group_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
5258 struct signal_struct
*sig
= p
->signal
;
5259 struct task_cputime cputime
;
5260 cputime_t rtime
, utime
, total
;
5262 thread_group_cputime(p
, &cputime
);
5264 total
= cputime_add(cputime
.utime
, cputime
.stime
);
5265 rtime
= nsecs_to_cputime(cputime
.sum_exec_runtime
);
5270 temp
= (u64
)(rtime
* cputime
.utime
);
5271 do_div(temp
, total
);
5272 utime
= (cputime_t
)temp
;
5276 sig
->prev_utime
= max(sig
->prev_utime
, utime
);
5277 sig
->prev_stime
= max(sig
->prev_stime
,
5278 cputime_sub(rtime
, sig
->prev_utime
));
5280 *ut
= sig
->prev_utime
;
5281 *st
= sig
->prev_stime
;
5286 * This function gets called by the timer code, with HZ frequency.
5287 * We call it with interrupts disabled.
5289 * It also gets called by the fork code, when changing the parent's
5292 void scheduler_tick(void)
5294 int cpu
= smp_processor_id();
5295 struct rq
*rq
= cpu_rq(cpu
);
5296 struct task_struct
*curr
= rq
->curr
;
5300 raw_spin_lock(&rq
->lock
);
5301 update_rq_clock(rq
);
5302 update_cpu_load(rq
);
5303 curr
->sched_class
->task_tick(rq
, curr
, 0);
5304 raw_spin_unlock(&rq
->lock
);
5306 perf_event_task_tick(curr
, cpu
);
5309 rq
->idle_at_tick
= idle_cpu(cpu
);
5310 trigger_load_balance(rq
, cpu
);
5314 notrace
unsigned long get_parent_ip(unsigned long addr
)
5316 if (in_lock_functions(addr
)) {
5317 addr
= CALLER_ADDR2
;
5318 if (in_lock_functions(addr
))
5319 addr
= CALLER_ADDR3
;
5324 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
5325 defined(CONFIG_PREEMPT_TRACER))
5327 void __kprobes
add_preempt_count(int val
)
5329 #ifdef CONFIG_DEBUG_PREEMPT
5333 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
5336 preempt_count() += val
;
5337 #ifdef CONFIG_DEBUG_PREEMPT
5339 * Spinlock count overflowing soon?
5341 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK
) >=
5344 if (preempt_count() == val
)
5345 trace_preempt_off(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
5347 EXPORT_SYMBOL(add_preempt_count
);
5349 void __kprobes
sub_preempt_count(int val
)
5351 #ifdef CONFIG_DEBUG_PREEMPT
5355 if (DEBUG_LOCKS_WARN_ON(val
> preempt_count()))
5358 * Is the spinlock portion underflowing?
5360 if (DEBUG_LOCKS_WARN_ON((val
< PREEMPT_MASK
) &&
5361 !(preempt_count() & PREEMPT_MASK
)))
5365 if (preempt_count() == val
)
5366 trace_preempt_on(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
5367 preempt_count() -= val
;
5369 EXPORT_SYMBOL(sub_preempt_count
);
5374 * Print scheduling while atomic bug:
5376 static noinline
void __schedule_bug(struct task_struct
*prev
)
5378 struct pt_regs
*regs
= get_irq_regs();
5380 pr_err("BUG: scheduling while atomic: %s/%d/0x%08x\n",
5381 prev
->comm
, prev
->pid
, preempt_count());
5383 debug_show_held_locks(prev
);
5385 if (irqs_disabled())
5386 print_irqtrace_events(prev
);
5395 * Various schedule()-time debugging checks and statistics:
5397 static inline void schedule_debug(struct task_struct
*prev
)
5400 * Test if we are atomic. Since do_exit() needs to call into
5401 * schedule() atomically, we ignore that path for now.
5402 * Otherwise, whine if we are scheduling when we should not be.
5404 if (unlikely(in_atomic_preempt_off() && !prev
->exit_state
))
5405 __schedule_bug(prev
);
5407 profile_hit(SCHED_PROFILING
, __builtin_return_address(0));
5409 schedstat_inc(this_rq(), sched_count
);
5410 #ifdef CONFIG_SCHEDSTATS
5411 if (unlikely(prev
->lock_depth
>= 0)) {
5412 schedstat_inc(this_rq(), bkl_count
);
5413 schedstat_inc(prev
, sched_info
.bkl_count
);
5418 static void put_prev_task(struct rq
*rq
, struct task_struct
*prev
)
5420 if (prev
->state
== TASK_RUNNING
) {
5421 u64 runtime
= prev
->se
.sum_exec_runtime
;
5423 runtime
-= prev
->se
.prev_sum_exec_runtime
;
5424 runtime
= min_t(u64
, runtime
, 2*sysctl_sched_migration_cost
);
5427 * In order to avoid avg_overlap growing stale when we are
5428 * indeed overlapping and hence not getting put to sleep, grow
5429 * the avg_overlap on preemption.
5431 * We use the average preemption runtime because that
5432 * correlates to the amount of cache footprint a task can
5435 update_avg(&prev
->se
.avg_overlap
, runtime
);
5437 prev
->sched_class
->put_prev_task(rq
, prev
);
5441 * Pick up the highest-prio task:
5443 static inline struct task_struct
*
5444 pick_next_task(struct rq
*rq
)
5446 const struct sched_class
*class;
5447 struct task_struct
*p
;
5450 * Optimization: we know that if all tasks are in
5451 * the fair class we can call that function directly:
5453 if (likely(rq
->nr_running
== rq
->cfs
.nr_running
)) {
5454 p
= fair_sched_class
.pick_next_task(rq
);
5459 class = sched_class_highest
;
5461 p
= class->pick_next_task(rq
);
5465 * Will never be NULL as the idle class always
5466 * returns a non-NULL p:
5468 class = class->next
;
5473 * schedule() is the main scheduler function.
5475 asmlinkage
void __sched
schedule(void)
5477 struct task_struct
*prev
, *next
;
5478 unsigned long *switch_count
;
5484 cpu
= smp_processor_id();
5488 switch_count
= &prev
->nivcsw
;
5490 release_kernel_lock(prev
);
5491 need_resched_nonpreemptible
:
5493 schedule_debug(prev
);
5495 if (sched_feat(HRTICK
))
5498 raw_spin_lock_irq(&rq
->lock
);
5499 update_rq_clock(rq
);
5500 clear_tsk_need_resched(prev
);
5502 if (prev
->state
&& !(preempt_count() & PREEMPT_ACTIVE
)) {
5503 if (unlikely(signal_pending_state(prev
->state
, prev
)))
5504 prev
->state
= TASK_RUNNING
;
5506 deactivate_task(rq
, prev
, 1);
5507 switch_count
= &prev
->nvcsw
;
5510 pre_schedule(rq
, prev
);
5512 if (unlikely(!rq
->nr_running
))
5513 idle_balance(cpu
, rq
);
5515 put_prev_task(rq
, prev
);
5516 next
= pick_next_task(rq
);
5518 if (likely(prev
!= next
)) {
5519 sched_info_switch(prev
, next
);
5520 perf_event_task_sched_out(prev
, next
, cpu
);
5526 context_switch(rq
, prev
, next
); /* unlocks the rq */
5528 * the context switch might have flipped the stack from under
5529 * us, hence refresh the local variables.
5531 cpu
= smp_processor_id();
5534 raw_spin_unlock_irq(&rq
->lock
);
5538 if (unlikely(reacquire_kernel_lock(current
) < 0))
5539 goto need_resched_nonpreemptible
;
5541 preempt_enable_no_resched();
5545 EXPORT_SYMBOL(schedule
);
5547 #ifdef CONFIG_MUTEX_SPIN_ON_OWNER
5549 * Look out! "owner" is an entirely speculative pointer
5550 * access and not reliable.
5552 int mutex_spin_on_owner(struct mutex
*lock
, struct thread_info
*owner
)
5557 if (!sched_feat(OWNER_SPIN
))
5560 #ifdef CONFIG_DEBUG_PAGEALLOC
5562 * Need to access the cpu field knowing that
5563 * DEBUG_PAGEALLOC could have unmapped it if
5564 * the mutex owner just released it and exited.
5566 if (probe_kernel_address(&owner
->cpu
, cpu
))
5573 * Even if the access succeeded (likely case),
5574 * the cpu field may no longer be valid.
5576 if (cpu
>= nr_cpumask_bits
)
5580 * We need to validate that we can do a
5581 * get_cpu() and that we have the percpu area.
5583 if (!cpu_online(cpu
))
5590 * Owner changed, break to re-assess state.
5592 if (lock
->owner
!= owner
)
5596 * Is that owner really running on that cpu?
5598 if (task_thread_info(rq
->curr
) != owner
|| need_resched())
5608 #ifdef CONFIG_PREEMPT
5610 * this is the entry point to schedule() from in-kernel preemption
5611 * off of preempt_enable. Kernel preemptions off return from interrupt
5612 * occur there and call schedule directly.
5614 asmlinkage
void __sched
preempt_schedule(void)
5616 struct thread_info
*ti
= current_thread_info();
5619 * If there is a non-zero preempt_count or interrupts are disabled,
5620 * we do not want to preempt the current task. Just return..
5622 if (likely(ti
->preempt_count
|| irqs_disabled()))
5626 add_preempt_count(PREEMPT_ACTIVE
);
5628 sub_preempt_count(PREEMPT_ACTIVE
);
5631 * Check again in case we missed a preemption opportunity
5632 * between schedule and now.
5635 } while (need_resched());
5637 EXPORT_SYMBOL(preempt_schedule
);
5640 * this is the entry point to schedule() from kernel preemption
5641 * off of irq context.
5642 * Note, that this is called and return with irqs disabled. This will
5643 * protect us against recursive calling from irq.
5645 asmlinkage
void __sched
preempt_schedule_irq(void)
5647 struct thread_info
*ti
= current_thread_info();
5649 /* Catch callers which need to be fixed */
5650 BUG_ON(ti
->preempt_count
|| !irqs_disabled());
5653 add_preempt_count(PREEMPT_ACTIVE
);
5656 local_irq_disable();
5657 sub_preempt_count(PREEMPT_ACTIVE
);
5660 * Check again in case we missed a preemption opportunity
5661 * between schedule and now.
5664 } while (need_resched());
5667 #endif /* CONFIG_PREEMPT */
5669 int default_wake_function(wait_queue_t
*curr
, unsigned mode
, int wake_flags
,
5672 return try_to_wake_up(curr
->private, mode
, wake_flags
);
5674 EXPORT_SYMBOL(default_wake_function
);
5677 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
5678 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
5679 * number) then we wake all the non-exclusive tasks and one exclusive task.
5681 * There are circumstances in which we can try to wake a task which has already
5682 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
5683 * zero in this (rare) case, and we handle it by continuing to scan the queue.
5685 static void __wake_up_common(wait_queue_head_t
*q
, unsigned int mode
,
5686 int nr_exclusive
, int wake_flags
, void *key
)
5688 wait_queue_t
*curr
, *next
;
5690 list_for_each_entry_safe(curr
, next
, &q
->task_list
, task_list
) {
5691 unsigned flags
= curr
->flags
;
5693 if (curr
->func(curr
, mode
, wake_flags
, key
) &&
5694 (flags
& WQ_FLAG_EXCLUSIVE
) && !--nr_exclusive
)
5700 * __wake_up - wake up threads blocked on a waitqueue.
5702 * @mode: which threads
5703 * @nr_exclusive: how many wake-one or wake-many threads to wake up
5704 * @key: is directly passed to the wakeup function
5706 * It may be assumed that this function implies a write memory barrier before
5707 * changing the task state if and only if any tasks are woken up.
5709 void __wake_up(wait_queue_head_t
*q
, unsigned int mode
,
5710 int nr_exclusive
, void *key
)
5712 unsigned long flags
;
5714 spin_lock_irqsave(&q
->lock
, flags
);
5715 __wake_up_common(q
, mode
, nr_exclusive
, 0, key
);
5716 spin_unlock_irqrestore(&q
->lock
, flags
);
5718 EXPORT_SYMBOL(__wake_up
);
5721 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
5723 void __wake_up_locked(wait_queue_head_t
*q
, unsigned int mode
)
5725 __wake_up_common(q
, mode
, 1, 0, NULL
);
5728 void __wake_up_locked_key(wait_queue_head_t
*q
, unsigned int mode
, void *key
)
5730 __wake_up_common(q
, mode
, 1, 0, key
);
5734 * __wake_up_sync_key - wake up threads blocked on a waitqueue.
5736 * @mode: which threads
5737 * @nr_exclusive: how many wake-one or wake-many threads to wake up
5738 * @key: opaque value to be passed to wakeup targets
5740 * The sync wakeup differs that the waker knows that it will schedule
5741 * away soon, so while the target thread will be woken up, it will not
5742 * be migrated to another CPU - ie. the two threads are 'synchronized'
5743 * with each other. This can prevent needless bouncing between CPUs.
5745 * On UP it can prevent extra preemption.
5747 * It may be assumed that this function implies a write memory barrier before
5748 * changing the task state if and only if any tasks are woken up.
5750 void __wake_up_sync_key(wait_queue_head_t
*q
, unsigned int mode
,
5751 int nr_exclusive
, void *key
)
5753 unsigned long flags
;
5754 int wake_flags
= WF_SYNC
;
5759 if (unlikely(!nr_exclusive
))
5762 spin_lock_irqsave(&q
->lock
, flags
);
5763 __wake_up_common(q
, mode
, nr_exclusive
, wake_flags
, key
);
5764 spin_unlock_irqrestore(&q
->lock
, flags
);
5766 EXPORT_SYMBOL_GPL(__wake_up_sync_key
);
5769 * __wake_up_sync - see __wake_up_sync_key()
5771 void __wake_up_sync(wait_queue_head_t
*q
, unsigned int mode
, int nr_exclusive
)
5773 __wake_up_sync_key(q
, mode
, nr_exclusive
, NULL
);
5775 EXPORT_SYMBOL_GPL(__wake_up_sync
); /* For internal use only */
5778 * complete: - signals a single thread waiting on this completion
5779 * @x: holds the state of this particular completion
5781 * This will wake up a single thread waiting on this completion. Threads will be
5782 * awakened in the same order in which they were queued.
5784 * See also complete_all(), wait_for_completion() and related routines.
5786 * It may be assumed that this function implies a write memory barrier before
5787 * changing the task state if and only if any tasks are woken up.
5789 void complete(struct completion
*x
)
5791 unsigned long flags
;
5793 spin_lock_irqsave(&x
->wait
.lock
, flags
);
5795 __wake_up_common(&x
->wait
, TASK_NORMAL
, 1, 0, NULL
);
5796 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
5798 EXPORT_SYMBOL(complete
);
5801 * complete_all: - signals all threads waiting on this completion
5802 * @x: holds the state of this particular completion
5804 * This will wake up all threads waiting on this particular completion event.
5806 * It may be assumed that this function implies a write memory barrier before
5807 * changing the task state if and only if any tasks are woken up.
5809 void complete_all(struct completion
*x
)
5811 unsigned long flags
;
5813 spin_lock_irqsave(&x
->wait
.lock
, flags
);
5814 x
->done
+= UINT_MAX
/2;
5815 __wake_up_common(&x
->wait
, TASK_NORMAL
, 0, 0, NULL
);
5816 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
5818 EXPORT_SYMBOL(complete_all
);
5820 static inline long __sched
5821 do_wait_for_common(struct completion
*x
, long timeout
, int state
)
5824 DECLARE_WAITQUEUE(wait
, current
);
5826 wait
.flags
|= WQ_FLAG_EXCLUSIVE
;
5827 __add_wait_queue_tail(&x
->wait
, &wait
);
5829 if (signal_pending_state(state
, current
)) {
5830 timeout
= -ERESTARTSYS
;
5833 __set_current_state(state
);
5834 spin_unlock_irq(&x
->wait
.lock
);
5835 timeout
= schedule_timeout(timeout
);
5836 spin_lock_irq(&x
->wait
.lock
);
5837 } while (!x
->done
&& timeout
);
5838 __remove_wait_queue(&x
->wait
, &wait
);
5843 return timeout
?: 1;
5847 wait_for_common(struct completion
*x
, long timeout
, int state
)
5851 spin_lock_irq(&x
->wait
.lock
);
5852 timeout
= do_wait_for_common(x
, timeout
, state
);
5853 spin_unlock_irq(&x
->wait
.lock
);
5858 * wait_for_completion: - waits for completion of a task
5859 * @x: holds the state of this particular completion
5861 * This waits to be signaled for completion of a specific task. It is NOT
5862 * interruptible and there is no timeout.
5864 * See also similar routines (i.e. wait_for_completion_timeout()) with timeout
5865 * and interrupt capability. Also see complete().
5867 void __sched
wait_for_completion(struct completion
*x
)
5869 wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_UNINTERRUPTIBLE
);
5871 EXPORT_SYMBOL(wait_for_completion
);
5874 * wait_for_completion_timeout: - waits for completion of a task (w/timeout)
5875 * @x: holds the state of this particular completion
5876 * @timeout: timeout value in jiffies
5878 * This waits for either a completion of a specific task to be signaled or for a
5879 * specified timeout to expire. The timeout is in jiffies. It is not
5882 unsigned long __sched
5883 wait_for_completion_timeout(struct completion
*x
, unsigned long timeout
)
5885 return wait_for_common(x
, timeout
, TASK_UNINTERRUPTIBLE
);
5887 EXPORT_SYMBOL(wait_for_completion_timeout
);
5890 * wait_for_completion_interruptible: - waits for completion of a task (w/intr)
5891 * @x: holds the state of this particular completion
5893 * This waits for completion of a specific task to be signaled. It is
5896 int __sched
wait_for_completion_interruptible(struct completion
*x
)
5898 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_INTERRUPTIBLE
);
5899 if (t
== -ERESTARTSYS
)
5903 EXPORT_SYMBOL(wait_for_completion_interruptible
);
5906 * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr))
5907 * @x: holds the state of this particular completion
5908 * @timeout: timeout value in jiffies
5910 * This waits for either a completion of a specific task to be signaled or for a
5911 * specified timeout to expire. It is interruptible. The timeout is in jiffies.
5913 unsigned long __sched
5914 wait_for_completion_interruptible_timeout(struct completion
*x
,
5915 unsigned long timeout
)
5917 return wait_for_common(x
, timeout
, TASK_INTERRUPTIBLE
);
5919 EXPORT_SYMBOL(wait_for_completion_interruptible_timeout
);
5922 * wait_for_completion_killable: - waits for completion of a task (killable)
5923 * @x: holds the state of this particular completion
5925 * This waits to be signaled for completion of a specific task. It can be
5926 * interrupted by a kill signal.
5928 int __sched
wait_for_completion_killable(struct completion
*x
)
5930 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_KILLABLE
);
5931 if (t
== -ERESTARTSYS
)
5935 EXPORT_SYMBOL(wait_for_completion_killable
);
5938 * try_wait_for_completion - try to decrement a completion without blocking
5939 * @x: completion structure
5941 * Returns: 0 if a decrement cannot be done without blocking
5942 * 1 if a decrement succeeded.
5944 * If a completion is being used as a counting completion,
5945 * attempt to decrement the counter without blocking. This
5946 * enables us to avoid waiting if the resource the completion
5947 * is protecting is not available.
5949 bool try_wait_for_completion(struct completion
*x
)
5951 unsigned long flags
;
5954 spin_lock_irqsave(&x
->wait
.lock
, flags
);
5959 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
5962 EXPORT_SYMBOL(try_wait_for_completion
);
5965 * completion_done - Test to see if a completion has any waiters
5966 * @x: completion structure
5968 * Returns: 0 if there are waiters (wait_for_completion() in progress)
5969 * 1 if there are no waiters.
5972 bool completion_done(struct completion
*x
)
5974 unsigned long flags
;
5977 spin_lock_irqsave(&x
->wait
.lock
, flags
);
5980 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
5983 EXPORT_SYMBOL(completion_done
);
5986 sleep_on_common(wait_queue_head_t
*q
, int state
, long timeout
)
5988 unsigned long flags
;
5991 init_waitqueue_entry(&wait
, current
);
5993 __set_current_state(state
);
5995 spin_lock_irqsave(&q
->lock
, flags
);
5996 __add_wait_queue(q
, &wait
);
5997 spin_unlock(&q
->lock
);
5998 timeout
= schedule_timeout(timeout
);
5999 spin_lock_irq(&q
->lock
);
6000 __remove_wait_queue(q
, &wait
);
6001 spin_unlock_irqrestore(&q
->lock
, flags
);
6006 void __sched
interruptible_sleep_on(wait_queue_head_t
*q
)
6008 sleep_on_common(q
, TASK_INTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
6010 EXPORT_SYMBOL(interruptible_sleep_on
);
6013 interruptible_sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
6015 return sleep_on_common(q
, TASK_INTERRUPTIBLE
, timeout
);
6017 EXPORT_SYMBOL(interruptible_sleep_on_timeout
);
6019 void __sched
sleep_on(wait_queue_head_t
*q
)
6021 sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
6023 EXPORT_SYMBOL(sleep_on
);
6025 long __sched
sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
6027 return sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, timeout
);
6029 EXPORT_SYMBOL(sleep_on_timeout
);
6031 #ifdef CONFIG_RT_MUTEXES
6034 * rt_mutex_setprio - set the current priority of a task
6036 * @prio: prio value (kernel-internal form)
6038 * This function changes the 'effective' priority of a task. It does
6039 * not touch ->normal_prio like __setscheduler().
6041 * Used by the rt_mutex code to implement priority inheritance logic.
6043 void rt_mutex_setprio(struct task_struct
*p
, int prio
)
6045 unsigned long flags
;
6046 int oldprio
, on_rq
, running
;
6048 const struct sched_class
*prev_class
= p
->sched_class
;
6050 BUG_ON(prio
< 0 || prio
> MAX_PRIO
);
6052 rq
= task_rq_lock(p
, &flags
);
6053 update_rq_clock(rq
);
6056 on_rq
= p
->se
.on_rq
;
6057 running
= task_current(rq
, p
);
6059 dequeue_task(rq
, p
, 0);
6061 p
->sched_class
->put_prev_task(rq
, p
);
6064 p
->sched_class
= &rt_sched_class
;
6066 p
->sched_class
= &fair_sched_class
;
6071 p
->sched_class
->set_curr_task(rq
);
6073 enqueue_task(rq
, p
, 0);
6075 check_class_changed(rq
, p
, prev_class
, oldprio
, running
);
6077 task_rq_unlock(rq
, &flags
);
6082 void set_user_nice(struct task_struct
*p
, long nice
)
6084 int old_prio
, delta
, on_rq
;
6085 unsigned long flags
;
6088 if (TASK_NICE(p
) == nice
|| nice
< -20 || nice
> 19)
6091 * We have to be careful, if called from sys_setpriority(),
6092 * the task might be in the middle of scheduling on another CPU.
6094 rq
= task_rq_lock(p
, &flags
);
6095 update_rq_clock(rq
);
6097 * The RT priorities are set via sched_setscheduler(), but we still
6098 * allow the 'normal' nice value to be set - but as expected
6099 * it wont have any effect on scheduling until the task is
6100 * SCHED_FIFO/SCHED_RR:
6102 if (task_has_rt_policy(p
)) {
6103 p
->static_prio
= NICE_TO_PRIO(nice
);
6106 on_rq
= p
->se
.on_rq
;
6108 dequeue_task(rq
, p
, 0);
6110 p
->static_prio
= NICE_TO_PRIO(nice
);
6113 p
->prio
= effective_prio(p
);
6114 delta
= p
->prio
- old_prio
;
6117 enqueue_task(rq
, p
, 0);
6119 * If the task increased its priority or is running and
6120 * lowered its priority, then reschedule its CPU:
6122 if (delta
< 0 || (delta
> 0 && task_running(rq
, p
)))
6123 resched_task(rq
->curr
);
6126 task_rq_unlock(rq
, &flags
);
6128 EXPORT_SYMBOL(set_user_nice
);
6131 * can_nice - check if a task can reduce its nice value
6135 int can_nice(const struct task_struct
*p
, const int nice
)
6137 /* convert nice value [19,-20] to rlimit style value [1,40] */
6138 int nice_rlim
= 20 - nice
;
6140 return (nice_rlim
<= p
->signal
->rlim
[RLIMIT_NICE
].rlim_cur
||
6141 capable(CAP_SYS_NICE
));
6144 #ifdef __ARCH_WANT_SYS_NICE
6147 * sys_nice - change the priority of the current process.
6148 * @increment: priority increment
6150 * sys_setpriority is a more generic, but much slower function that
6151 * does similar things.
6153 SYSCALL_DEFINE1(nice
, int, increment
)
6158 * Setpriority might change our priority at the same moment.
6159 * We don't have to worry. Conceptually one call occurs first
6160 * and we have a single winner.
6162 if (increment
< -40)
6167 nice
= TASK_NICE(current
) + increment
;
6173 if (increment
< 0 && !can_nice(current
, nice
))
6176 retval
= security_task_setnice(current
, nice
);
6180 set_user_nice(current
, nice
);
6187 * task_prio - return the priority value of a given task.
6188 * @p: the task in question.
6190 * This is the priority value as seen by users in /proc.
6191 * RT tasks are offset by -200. Normal tasks are centered
6192 * around 0, value goes from -16 to +15.
6194 int task_prio(const struct task_struct
*p
)
6196 return p
->prio
- MAX_RT_PRIO
;
6200 * task_nice - return the nice value of a given task.
6201 * @p: the task in question.
6203 int task_nice(const struct task_struct
*p
)
6205 return TASK_NICE(p
);
6207 EXPORT_SYMBOL(task_nice
);
6210 * idle_cpu - is a given cpu idle currently?
6211 * @cpu: the processor in question.
6213 int idle_cpu(int cpu
)
6215 return cpu_curr(cpu
) == cpu_rq(cpu
)->idle
;
6219 * idle_task - return the idle task for a given cpu.
6220 * @cpu: the processor in question.
6222 struct task_struct
*idle_task(int cpu
)
6224 return cpu_rq(cpu
)->idle
;
6228 * find_process_by_pid - find a process with a matching PID value.
6229 * @pid: the pid in question.
6231 static struct task_struct
*find_process_by_pid(pid_t pid
)
6233 return pid
? find_task_by_vpid(pid
) : current
;
6236 /* Actually do priority change: must hold rq lock. */
6238 __setscheduler(struct rq
*rq
, struct task_struct
*p
, int policy
, int prio
)
6240 BUG_ON(p
->se
.on_rq
);
6243 p
->rt_priority
= prio
;
6244 p
->normal_prio
= normal_prio(p
);
6245 /* we are holding p->pi_lock already */
6246 p
->prio
= rt_mutex_getprio(p
);
6247 if (rt_prio(p
->prio
))
6248 p
->sched_class
= &rt_sched_class
;
6250 p
->sched_class
= &fair_sched_class
;
6255 * check the target process has a UID that matches the current process's
6257 static bool check_same_owner(struct task_struct
*p
)
6259 const struct cred
*cred
= current_cred(), *pcred
;
6263 pcred
= __task_cred(p
);
6264 match
= (cred
->euid
== pcred
->euid
||
6265 cred
->euid
== pcred
->uid
);
6270 static int __sched_setscheduler(struct task_struct
*p
, int policy
,
6271 struct sched_param
*param
, bool user
)
6273 int retval
, oldprio
, oldpolicy
= -1, on_rq
, running
;
6274 unsigned long flags
;
6275 const struct sched_class
*prev_class
= p
->sched_class
;
6279 /* may grab non-irq protected spin_locks */
6280 BUG_ON(in_interrupt());
6282 /* double check policy once rq lock held */
6284 reset_on_fork
= p
->sched_reset_on_fork
;
6285 policy
= oldpolicy
= p
->policy
;
6287 reset_on_fork
= !!(policy
& SCHED_RESET_ON_FORK
);
6288 policy
&= ~SCHED_RESET_ON_FORK
;
6290 if (policy
!= SCHED_FIFO
&& policy
!= SCHED_RR
&&
6291 policy
!= SCHED_NORMAL
&& policy
!= SCHED_BATCH
&&
6292 policy
!= SCHED_IDLE
)
6297 * Valid priorities for SCHED_FIFO and SCHED_RR are
6298 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
6299 * SCHED_BATCH and SCHED_IDLE is 0.
6301 if (param
->sched_priority
< 0 ||
6302 (p
->mm
&& param
->sched_priority
> MAX_USER_RT_PRIO
-1) ||
6303 (!p
->mm
&& param
->sched_priority
> MAX_RT_PRIO
-1))
6305 if (rt_policy(policy
) != (param
->sched_priority
!= 0))
6309 * Allow unprivileged RT tasks to decrease priority:
6311 if (user
&& !capable(CAP_SYS_NICE
)) {
6312 if (rt_policy(policy
)) {
6313 unsigned long rlim_rtprio
;
6315 if (!lock_task_sighand(p
, &flags
))
6317 rlim_rtprio
= p
->signal
->rlim
[RLIMIT_RTPRIO
].rlim_cur
;
6318 unlock_task_sighand(p
, &flags
);
6320 /* can't set/change the rt policy */
6321 if (policy
!= p
->policy
&& !rlim_rtprio
)
6324 /* can't increase priority */
6325 if (param
->sched_priority
> p
->rt_priority
&&
6326 param
->sched_priority
> rlim_rtprio
)
6330 * Like positive nice levels, dont allow tasks to
6331 * move out of SCHED_IDLE either:
6333 if (p
->policy
== SCHED_IDLE
&& policy
!= SCHED_IDLE
)
6336 /* can't change other user's priorities */
6337 if (!check_same_owner(p
))
6340 /* Normal users shall not reset the sched_reset_on_fork flag */
6341 if (p
->sched_reset_on_fork
&& !reset_on_fork
)
6346 #ifdef CONFIG_RT_GROUP_SCHED
6348 * Do not allow realtime tasks into groups that have no runtime
6351 if (rt_bandwidth_enabled() && rt_policy(policy
) &&
6352 task_group(p
)->rt_bandwidth
.rt_runtime
== 0)
6356 retval
= security_task_setscheduler(p
, policy
, param
);
6362 * make sure no PI-waiters arrive (or leave) while we are
6363 * changing the priority of the task:
6365 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
6367 * To be able to change p->policy safely, the apropriate
6368 * runqueue lock must be held.
6370 rq
= __task_rq_lock(p
);
6371 /* recheck policy now with rq lock held */
6372 if (unlikely(oldpolicy
!= -1 && oldpolicy
!= p
->policy
)) {
6373 policy
= oldpolicy
= -1;
6374 __task_rq_unlock(rq
);
6375 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
6378 update_rq_clock(rq
);
6379 on_rq
= p
->se
.on_rq
;
6380 running
= task_current(rq
, p
);
6382 deactivate_task(rq
, p
, 0);
6384 p
->sched_class
->put_prev_task(rq
, p
);
6386 p
->sched_reset_on_fork
= reset_on_fork
;
6389 __setscheduler(rq
, p
, policy
, param
->sched_priority
);
6392 p
->sched_class
->set_curr_task(rq
);
6394 activate_task(rq
, p
, 0);
6396 check_class_changed(rq
, p
, prev_class
, oldprio
, running
);
6398 __task_rq_unlock(rq
);
6399 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
6401 rt_mutex_adjust_pi(p
);
6407 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
6408 * @p: the task in question.
6409 * @policy: new policy.
6410 * @param: structure containing the new RT priority.
6412 * NOTE that the task may be already dead.
6414 int sched_setscheduler(struct task_struct
*p
, int policy
,
6415 struct sched_param
*param
)
6417 return __sched_setscheduler(p
, policy
, param
, true);
6419 EXPORT_SYMBOL_GPL(sched_setscheduler
);
6422 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
6423 * @p: the task in question.
6424 * @policy: new policy.
6425 * @param: structure containing the new RT priority.
6427 * Just like sched_setscheduler, only don't bother checking if the
6428 * current context has permission. For example, this is needed in
6429 * stop_machine(): we create temporary high priority worker threads,
6430 * but our caller might not have that capability.
6432 int sched_setscheduler_nocheck(struct task_struct
*p
, int policy
,
6433 struct sched_param
*param
)
6435 return __sched_setscheduler(p
, policy
, param
, false);
6439 do_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
6441 struct sched_param lparam
;
6442 struct task_struct
*p
;
6445 if (!param
|| pid
< 0)
6447 if (copy_from_user(&lparam
, param
, sizeof(struct sched_param
)))
6452 p
= find_process_by_pid(pid
);
6454 retval
= sched_setscheduler(p
, policy
, &lparam
);
6461 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
6462 * @pid: the pid in question.
6463 * @policy: new policy.
6464 * @param: structure containing the new RT priority.
6466 SYSCALL_DEFINE3(sched_setscheduler
, pid_t
, pid
, int, policy
,
6467 struct sched_param __user
*, param
)
6469 /* negative values for policy are not valid */
6473 return do_sched_setscheduler(pid
, policy
, param
);
6477 * sys_sched_setparam - set/change the RT priority of a thread
6478 * @pid: the pid in question.
6479 * @param: structure containing the new RT priority.
6481 SYSCALL_DEFINE2(sched_setparam
, pid_t
, pid
, struct sched_param __user
*, param
)
6483 return do_sched_setscheduler(pid
, -1, param
);
6487 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
6488 * @pid: the pid in question.
6490 SYSCALL_DEFINE1(sched_getscheduler
, pid_t
, pid
)
6492 struct task_struct
*p
;
6500 p
= find_process_by_pid(pid
);
6502 retval
= security_task_getscheduler(p
);
6505 | (p
->sched_reset_on_fork
? SCHED_RESET_ON_FORK
: 0);
6512 * sys_sched_getparam - get the RT priority of a thread
6513 * @pid: the pid in question.
6514 * @param: structure containing the RT priority.
6516 SYSCALL_DEFINE2(sched_getparam
, pid_t
, pid
, struct sched_param __user
*, param
)
6518 struct sched_param lp
;
6519 struct task_struct
*p
;
6522 if (!param
|| pid
< 0)
6526 p
= find_process_by_pid(pid
);
6531 retval
= security_task_getscheduler(p
);
6535 lp
.sched_priority
= p
->rt_priority
;
6539 * This one might sleep, we cannot do it with a spinlock held ...
6541 retval
= copy_to_user(param
, &lp
, sizeof(*param
)) ? -EFAULT
: 0;
6550 long sched_setaffinity(pid_t pid
, const struct cpumask
*in_mask
)
6552 cpumask_var_t cpus_allowed
, new_mask
;
6553 struct task_struct
*p
;
6559 p
= find_process_by_pid(pid
);
6566 /* Prevent p going away */
6570 if (!alloc_cpumask_var(&cpus_allowed
, GFP_KERNEL
)) {
6574 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
)) {
6576 goto out_free_cpus_allowed
;
6579 if (!check_same_owner(p
) && !capable(CAP_SYS_NICE
))
6582 retval
= security_task_setscheduler(p
, 0, NULL
);
6586 cpuset_cpus_allowed(p
, cpus_allowed
);
6587 cpumask_and(new_mask
, in_mask
, cpus_allowed
);
6589 retval
= set_cpus_allowed_ptr(p
, new_mask
);
6592 cpuset_cpus_allowed(p
, cpus_allowed
);
6593 if (!cpumask_subset(new_mask
, cpus_allowed
)) {
6595 * We must have raced with a concurrent cpuset
6596 * update. Just reset the cpus_allowed to the
6597 * cpuset's cpus_allowed
6599 cpumask_copy(new_mask
, cpus_allowed
);
6604 free_cpumask_var(new_mask
);
6605 out_free_cpus_allowed
:
6606 free_cpumask_var(cpus_allowed
);
6613 static int get_user_cpu_mask(unsigned long __user
*user_mask_ptr
, unsigned len
,
6614 struct cpumask
*new_mask
)
6616 if (len
< cpumask_size())
6617 cpumask_clear(new_mask
);
6618 else if (len
> cpumask_size())
6619 len
= cpumask_size();
6621 return copy_from_user(new_mask
, user_mask_ptr
, len
) ? -EFAULT
: 0;
6625 * sys_sched_setaffinity - set the cpu affinity of a process
6626 * @pid: pid of the process
6627 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
6628 * @user_mask_ptr: user-space pointer to the new cpu mask
6630 SYSCALL_DEFINE3(sched_setaffinity
, pid_t
, pid
, unsigned int, len
,
6631 unsigned long __user
*, user_mask_ptr
)
6633 cpumask_var_t new_mask
;
6636 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
))
6639 retval
= get_user_cpu_mask(user_mask_ptr
, len
, new_mask
);
6641 retval
= sched_setaffinity(pid
, new_mask
);
6642 free_cpumask_var(new_mask
);
6646 long sched_getaffinity(pid_t pid
, struct cpumask
*mask
)
6648 struct task_struct
*p
;
6649 unsigned long flags
;
6657 p
= find_process_by_pid(pid
);
6661 retval
= security_task_getscheduler(p
);
6665 rq
= task_rq_lock(p
, &flags
);
6666 cpumask_and(mask
, &p
->cpus_allowed
, cpu_online_mask
);
6667 task_rq_unlock(rq
, &flags
);
6677 * sys_sched_getaffinity - get the cpu affinity of a process
6678 * @pid: pid of the process
6679 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
6680 * @user_mask_ptr: user-space pointer to hold the current cpu mask
6682 SYSCALL_DEFINE3(sched_getaffinity
, pid_t
, pid
, unsigned int, len
,
6683 unsigned long __user
*, user_mask_ptr
)
6688 if (len
< cpumask_size())
6691 if (!alloc_cpumask_var(&mask
, GFP_KERNEL
))
6694 ret
= sched_getaffinity(pid
, mask
);
6696 if (copy_to_user(user_mask_ptr
, mask
, cpumask_size()))
6699 ret
= cpumask_size();
6701 free_cpumask_var(mask
);
6707 * sys_sched_yield - yield the current processor to other threads.
6709 * This function yields the current CPU to other tasks. If there are no
6710 * other threads running on this CPU then this function will return.
6712 SYSCALL_DEFINE0(sched_yield
)
6714 struct rq
*rq
= this_rq_lock();
6716 schedstat_inc(rq
, yld_count
);
6717 current
->sched_class
->yield_task(rq
);
6720 * Since we are going to call schedule() anyway, there's
6721 * no need to preempt or enable interrupts:
6723 __release(rq
->lock
);
6724 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
6725 do_raw_spin_unlock(&rq
->lock
);
6726 preempt_enable_no_resched();
6733 static inline int should_resched(void)
6735 return need_resched() && !(preempt_count() & PREEMPT_ACTIVE
);
6738 static void __cond_resched(void)
6740 add_preempt_count(PREEMPT_ACTIVE
);
6742 sub_preempt_count(PREEMPT_ACTIVE
);
6745 int __sched
_cond_resched(void)
6747 if (should_resched()) {
6753 EXPORT_SYMBOL(_cond_resched
);
6756 * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
6757 * call schedule, and on return reacquire the lock.
6759 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
6760 * operations here to prevent schedule() from being called twice (once via
6761 * spin_unlock(), once by hand).
6763 int __cond_resched_lock(spinlock_t
*lock
)
6765 int resched
= should_resched();
6768 lockdep_assert_held(lock
);
6770 if (spin_needbreak(lock
) || resched
) {
6781 EXPORT_SYMBOL(__cond_resched_lock
);
6783 int __sched
__cond_resched_softirq(void)
6785 BUG_ON(!in_softirq());
6787 if (should_resched()) {
6795 EXPORT_SYMBOL(__cond_resched_softirq
);
6798 * yield - yield the current processor to other threads.
6800 * This is a shortcut for kernel-space yielding - it marks the
6801 * thread runnable and calls sys_sched_yield().
6803 void __sched
yield(void)
6805 set_current_state(TASK_RUNNING
);
6808 EXPORT_SYMBOL(yield
);
6811 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
6812 * that process accounting knows that this is a task in IO wait state.
6814 void __sched
io_schedule(void)
6816 struct rq
*rq
= raw_rq();
6818 delayacct_blkio_start();
6819 atomic_inc(&rq
->nr_iowait
);
6820 current
->in_iowait
= 1;
6822 current
->in_iowait
= 0;
6823 atomic_dec(&rq
->nr_iowait
);
6824 delayacct_blkio_end();
6826 EXPORT_SYMBOL(io_schedule
);
6828 long __sched
io_schedule_timeout(long timeout
)
6830 struct rq
*rq
= raw_rq();
6833 delayacct_blkio_start();
6834 atomic_inc(&rq
->nr_iowait
);
6835 current
->in_iowait
= 1;
6836 ret
= schedule_timeout(timeout
);
6837 current
->in_iowait
= 0;
6838 atomic_dec(&rq
->nr_iowait
);
6839 delayacct_blkio_end();
6844 * sys_sched_get_priority_max - return maximum RT priority.
6845 * @policy: scheduling class.
6847 * this syscall returns the maximum rt_priority that can be used
6848 * by a given scheduling class.
6850 SYSCALL_DEFINE1(sched_get_priority_max
, int, policy
)
6857 ret
= MAX_USER_RT_PRIO
-1;
6869 * sys_sched_get_priority_min - return minimum RT priority.
6870 * @policy: scheduling class.
6872 * this syscall returns the minimum rt_priority that can be used
6873 * by a given scheduling class.
6875 SYSCALL_DEFINE1(sched_get_priority_min
, int, policy
)
6893 * sys_sched_rr_get_interval - return the default timeslice of a process.
6894 * @pid: pid of the process.
6895 * @interval: userspace pointer to the timeslice value.
6897 * this syscall writes the default timeslice value of a given process
6898 * into the user-space timespec buffer. A value of '0' means infinity.
6900 SYSCALL_DEFINE2(sched_rr_get_interval
, pid_t
, pid
,
6901 struct timespec __user
*, interval
)
6903 struct task_struct
*p
;
6904 unsigned int time_slice
;
6905 unsigned long flags
;
6915 p
= find_process_by_pid(pid
);
6919 retval
= security_task_getscheduler(p
);
6923 rq
= task_rq_lock(p
, &flags
);
6924 time_slice
= p
->sched_class
->get_rr_interval(rq
, p
);
6925 task_rq_unlock(rq
, &flags
);
6928 jiffies_to_timespec(time_slice
, &t
);
6929 retval
= copy_to_user(interval
, &t
, sizeof(t
)) ? -EFAULT
: 0;
6937 static const char stat_nam
[] = TASK_STATE_TO_CHAR_STR
;
6939 void sched_show_task(struct task_struct
*p
)
6941 unsigned long free
= 0;
6944 state
= p
->state
? __ffs(p
->state
) + 1 : 0;
6945 pr_info("%-13.13s %c", p
->comm
,
6946 state
< sizeof(stat_nam
) - 1 ? stat_nam
[state
] : '?');
6947 #if BITS_PER_LONG == 32
6948 if (state
== TASK_RUNNING
)
6949 pr_cont(" running ");
6951 pr_cont(" %08lx ", thread_saved_pc(p
));
6953 if (state
== TASK_RUNNING
)
6954 pr_cont(" running task ");
6956 pr_cont(" %016lx ", thread_saved_pc(p
));
6958 #ifdef CONFIG_DEBUG_STACK_USAGE
6959 free
= stack_not_used(p
);
6961 pr_cont("%5lu %5d %6d 0x%08lx\n", free
,
6962 task_pid_nr(p
), task_pid_nr(p
->real_parent
),
6963 (unsigned long)task_thread_info(p
)->flags
);
6965 show_stack(p
, NULL
);
6968 void show_state_filter(unsigned long state_filter
)
6970 struct task_struct
*g
, *p
;
6972 #if BITS_PER_LONG == 32
6973 pr_info(" task PC stack pid father\n");
6975 pr_info(" task PC stack pid father\n");
6977 read_lock(&tasklist_lock
);
6978 do_each_thread(g
, p
) {
6980 * reset the NMI-timeout, listing all files on a slow
6981 * console might take alot of time:
6983 touch_nmi_watchdog();
6984 if (!state_filter
|| (p
->state
& state_filter
))
6986 } while_each_thread(g
, p
);
6988 touch_all_softlockup_watchdogs();
6990 #ifdef CONFIG_SCHED_DEBUG
6991 sysrq_sched_debug_show();
6993 read_unlock(&tasklist_lock
);
6995 * Only show locks if all tasks are dumped:
6998 debug_show_all_locks();
7001 void __cpuinit
init_idle_bootup_task(struct task_struct
*idle
)
7003 idle
->sched_class
= &idle_sched_class
;
7007 * init_idle - set up an idle thread for a given CPU
7008 * @idle: task in question
7009 * @cpu: cpu the idle task belongs to
7011 * NOTE: this function does not set the idle thread's NEED_RESCHED
7012 * flag, to make booting more robust.
7014 void __cpuinit
init_idle(struct task_struct
*idle
, int cpu
)
7016 struct rq
*rq
= cpu_rq(cpu
);
7017 unsigned long flags
;
7019 raw_spin_lock_irqsave(&rq
->lock
, flags
);
7022 idle
->state
= TASK_RUNNING
;
7023 idle
->se
.exec_start
= sched_clock();
7025 cpumask_copy(&idle
->cpus_allowed
, cpumask_of(cpu
));
7026 __set_task_cpu(idle
, cpu
);
7028 rq
->curr
= rq
->idle
= idle
;
7029 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
7032 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
7034 /* Set the preempt count _outside_ the spinlocks! */
7035 #if defined(CONFIG_PREEMPT)
7036 task_thread_info(idle
)->preempt_count
= (idle
->lock_depth
>= 0);
7038 task_thread_info(idle
)->preempt_count
= 0;
7041 * The idle tasks have their own, simple scheduling class:
7043 idle
->sched_class
= &idle_sched_class
;
7044 ftrace_graph_init_task(idle
);
7048 * In a system that switches off the HZ timer nohz_cpu_mask
7049 * indicates which cpus entered this state. This is used
7050 * in the rcu update to wait only for active cpus. For system
7051 * which do not switch off the HZ timer nohz_cpu_mask should
7052 * always be CPU_BITS_NONE.
7054 cpumask_var_t nohz_cpu_mask
;
7057 * Increase the granularity value when there are more CPUs,
7058 * because with more CPUs the 'effective latency' as visible
7059 * to users decreases. But the relationship is not linear,
7060 * so pick a second-best guess by going with the log2 of the
7063 * This idea comes from the SD scheduler of Con Kolivas:
7065 static int get_update_sysctl_factor(void)
7067 unsigned int cpus
= min_t(int, num_online_cpus(), 8);
7068 unsigned int factor
;
7070 switch (sysctl_sched_tunable_scaling
) {
7071 case SCHED_TUNABLESCALING_NONE
:
7074 case SCHED_TUNABLESCALING_LINEAR
:
7077 case SCHED_TUNABLESCALING_LOG
:
7079 factor
= 1 + ilog2(cpus
);
7086 static void update_sysctl(void)
7088 unsigned int factor
= get_update_sysctl_factor();
7090 #define SET_SYSCTL(name) \
7091 (sysctl_##name = (factor) * normalized_sysctl_##name)
7092 SET_SYSCTL(sched_min_granularity
);
7093 SET_SYSCTL(sched_latency
);
7094 SET_SYSCTL(sched_wakeup_granularity
);
7095 SET_SYSCTL(sched_shares_ratelimit
);
7099 static inline void sched_init_granularity(void)
7106 * This is how migration works:
7108 * 1) we queue a struct migration_req structure in the source CPU's
7109 * runqueue and wake up that CPU's migration thread.
7110 * 2) we down() the locked semaphore => thread blocks.
7111 * 3) migration thread wakes up (implicitly it forces the migrated
7112 * thread off the CPU)
7113 * 4) it gets the migration request and checks whether the migrated
7114 * task is still in the wrong runqueue.
7115 * 5) if it's in the wrong runqueue then the migration thread removes
7116 * it and puts it into the right queue.
7117 * 6) migration thread up()s the semaphore.
7118 * 7) we wake up and the migration is done.
7122 * Change a given task's CPU affinity. Migrate the thread to a
7123 * proper CPU and schedule it away if the CPU it's executing on
7124 * is removed from the allowed bitmask.
7126 * NOTE: the caller must have a valid reference to the task, the
7127 * task must not exit() & deallocate itself prematurely. The
7128 * call is not atomic; no spinlocks may be held.
7130 int set_cpus_allowed_ptr(struct task_struct
*p
, const struct cpumask
*new_mask
)
7132 struct migration_req req
;
7133 unsigned long flags
;
7138 * Since we rely on wake-ups to migrate sleeping tasks, don't change
7139 * the ->cpus_allowed mask from under waking tasks, which would be
7140 * possible when we change rq->lock in ttwu(), so synchronize against
7141 * TASK_WAKING to avoid that.
7144 while (p
->state
== TASK_WAKING
)
7147 rq
= task_rq_lock(p
, &flags
);
7149 if (p
->state
== TASK_WAKING
) {
7150 task_rq_unlock(rq
, &flags
);
7154 if (!cpumask_intersects(new_mask
, cpu_active_mask
)) {
7159 if (unlikely((p
->flags
& PF_THREAD_BOUND
) && p
!= current
&&
7160 !cpumask_equal(&p
->cpus_allowed
, new_mask
))) {
7165 if (p
->sched_class
->set_cpus_allowed
)
7166 p
->sched_class
->set_cpus_allowed(p
, new_mask
);
7168 cpumask_copy(&p
->cpus_allowed
, new_mask
);
7169 p
->rt
.nr_cpus_allowed
= cpumask_weight(new_mask
);
7172 /* Can the task run on the task's current CPU? If so, we're done */
7173 if (cpumask_test_cpu(task_cpu(p
), new_mask
))
7176 if (migrate_task(p
, cpumask_any_and(cpu_active_mask
, new_mask
), &req
)) {
7177 /* Need help from migration thread: drop lock and wait. */
7178 struct task_struct
*mt
= rq
->migration_thread
;
7180 get_task_struct(mt
);
7181 task_rq_unlock(rq
, &flags
);
7182 wake_up_process(rq
->migration_thread
);
7183 put_task_struct(mt
);
7184 wait_for_completion(&req
.done
);
7185 tlb_migrate_finish(p
->mm
);
7189 task_rq_unlock(rq
, &flags
);
7193 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr
);
7196 * Move (not current) task off this cpu, onto dest cpu. We're doing
7197 * this because either it can't run here any more (set_cpus_allowed()
7198 * away from this CPU, or CPU going down), or because we're
7199 * attempting to rebalance this task on exec (sched_exec).
7201 * So we race with normal scheduler movements, but that's OK, as long
7202 * as the task is no longer on this CPU.
7204 * Returns non-zero if task was successfully migrated.
7206 static int __migrate_task(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
7208 struct rq
*rq_dest
, *rq_src
;
7211 if (unlikely(!cpu_active(dest_cpu
)))
7214 rq_src
= cpu_rq(src_cpu
);
7215 rq_dest
= cpu_rq(dest_cpu
);
7217 double_rq_lock(rq_src
, rq_dest
);
7218 /* Already moved. */
7219 if (task_cpu(p
) != src_cpu
)
7221 /* Affinity changed (again). */
7222 if (!cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
))
7226 * If we're not on a rq, the next wake-up will ensure we're
7230 deactivate_task(rq_src
, p
, 0);
7231 set_task_cpu(p
, dest_cpu
);
7232 activate_task(rq_dest
, p
, 0);
7233 check_preempt_curr(rq_dest
, p
, 0);
7238 double_rq_unlock(rq_src
, rq_dest
);
7242 #define RCU_MIGRATION_IDLE 0
7243 #define RCU_MIGRATION_NEED_QS 1
7244 #define RCU_MIGRATION_GOT_QS 2
7245 #define RCU_MIGRATION_MUST_SYNC 3
7248 * migration_thread - this is a highprio system thread that performs
7249 * thread migration by bumping thread off CPU then 'pushing' onto
7252 static int migration_thread(void *data
)
7255 int cpu
= (long)data
;
7259 BUG_ON(rq
->migration_thread
!= current
);
7261 set_current_state(TASK_INTERRUPTIBLE
);
7262 while (!kthread_should_stop()) {
7263 struct migration_req
*req
;
7264 struct list_head
*head
;
7266 raw_spin_lock_irq(&rq
->lock
);
7268 if (cpu_is_offline(cpu
)) {
7269 raw_spin_unlock_irq(&rq
->lock
);
7273 if (rq
->active_balance
) {
7274 active_load_balance(rq
, cpu
);
7275 rq
->active_balance
= 0;
7278 head
= &rq
->migration_queue
;
7280 if (list_empty(head
)) {
7281 raw_spin_unlock_irq(&rq
->lock
);
7283 set_current_state(TASK_INTERRUPTIBLE
);
7286 req
= list_entry(head
->next
, struct migration_req
, list
);
7287 list_del_init(head
->next
);
7289 if (req
->task
!= NULL
) {
7290 raw_spin_unlock(&rq
->lock
);
7291 __migrate_task(req
->task
, cpu
, req
->dest_cpu
);
7292 } else if (likely(cpu
== (badcpu
= smp_processor_id()))) {
7293 req
->dest_cpu
= RCU_MIGRATION_GOT_QS
;
7294 raw_spin_unlock(&rq
->lock
);
7296 req
->dest_cpu
= RCU_MIGRATION_MUST_SYNC
;
7297 raw_spin_unlock(&rq
->lock
);
7298 WARN_ONCE(1, "migration_thread() on CPU %d, expected %d\n", badcpu
, cpu
);
7302 complete(&req
->done
);
7304 __set_current_state(TASK_RUNNING
);
7309 #ifdef CONFIG_HOTPLUG_CPU
7311 static int __migrate_task_irq(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
7315 local_irq_disable();
7316 ret
= __migrate_task(p
, src_cpu
, dest_cpu
);
7322 * Figure out where task on dead CPU should go, use force if necessary.
7324 static void move_task_off_dead_cpu(int dead_cpu
, struct task_struct
*p
)
7329 dest_cpu
= select_fallback_rq(dead_cpu
, p
);
7331 /* It can have affinity changed while we were choosing. */
7332 if (unlikely(!__migrate_task_irq(p
, dead_cpu
, dest_cpu
)))
7337 * While a dead CPU has no uninterruptible tasks queued at this point,
7338 * it might still have a nonzero ->nr_uninterruptible counter, because
7339 * for performance reasons the counter is not stricly tracking tasks to
7340 * their home CPUs. So we just add the counter to another CPU's counter,
7341 * to keep the global sum constant after CPU-down:
7343 static void migrate_nr_uninterruptible(struct rq
*rq_src
)
7345 struct rq
*rq_dest
= cpu_rq(cpumask_any(cpu_active_mask
));
7346 unsigned long flags
;
7348 local_irq_save(flags
);
7349 double_rq_lock(rq_src
, rq_dest
);
7350 rq_dest
->nr_uninterruptible
+= rq_src
->nr_uninterruptible
;
7351 rq_src
->nr_uninterruptible
= 0;
7352 double_rq_unlock(rq_src
, rq_dest
);
7353 local_irq_restore(flags
);
7356 /* Run through task list and migrate tasks from the dead cpu. */
7357 static void migrate_live_tasks(int src_cpu
)
7359 struct task_struct
*p
, *t
;
7361 read_lock(&tasklist_lock
);
7363 do_each_thread(t
, p
) {
7367 if (task_cpu(p
) == src_cpu
)
7368 move_task_off_dead_cpu(src_cpu
, p
);
7369 } while_each_thread(t
, p
);
7371 read_unlock(&tasklist_lock
);
7375 * Schedules idle task to be the next runnable task on current CPU.
7376 * It does so by boosting its priority to highest possible.
7377 * Used by CPU offline code.
7379 void sched_idle_next(void)
7381 int this_cpu
= smp_processor_id();
7382 struct rq
*rq
= cpu_rq(this_cpu
);
7383 struct task_struct
*p
= rq
->idle
;
7384 unsigned long flags
;
7386 /* cpu has to be offline */
7387 BUG_ON(cpu_online(this_cpu
));
7390 * Strictly not necessary since rest of the CPUs are stopped by now
7391 * and interrupts disabled on the current cpu.
7393 raw_spin_lock_irqsave(&rq
->lock
, flags
);
7395 __setscheduler(rq
, p
, SCHED_FIFO
, MAX_RT_PRIO
-1);
7397 update_rq_clock(rq
);
7398 activate_task(rq
, p
, 0);
7400 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
7404 * Ensures that the idle task is using init_mm right before its cpu goes
7407 void idle_task_exit(void)
7409 struct mm_struct
*mm
= current
->active_mm
;
7411 BUG_ON(cpu_online(smp_processor_id()));
7414 switch_mm(mm
, &init_mm
, current
);
7418 /* called under rq->lock with disabled interrupts */
7419 static void migrate_dead(unsigned int dead_cpu
, struct task_struct
*p
)
7421 struct rq
*rq
= cpu_rq(dead_cpu
);
7423 /* Must be exiting, otherwise would be on tasklist. */
7424 BUG_ON(!p
->exit_state
);
7426 /* Cannot have done final schedule yet: would have vanished. */
7427 BUG_ON(p
->state
== TASK_DEAD
);
7432 * Drop lock around migration; if someone else moves it,
7433 * that's OK. No task can be added to this CPU, so iteration is
7436 raw_spin_unlock_irq(&rq
->lock
);
7437 move_task_off_dead_cpu(dead_cpu
, p
);
7438 raw_spin_lock_irq(&rq
->lock
);
7443 /* release_task() removes task from tasklist, so we won't find dead tasks. */
7444 static void migrate_dead_tasks(unsigned int dead_cpu
)
7446 struct rq
*rq
= cpu_rq(dead_cpu
);
7447 struct task_struct
*next
;
7450 if (!rq
->nr_running
)
7452 update_rq_clock(rq
);
7453 next
= pick_next_task(rq
);
7456 next
->sched_class
->put_prev_task(rq
, next
);
7457 migrate_dead(dead_cpu
, next
);
7463 * remove the tasks which were accounted by rq from calc_load_tasks.
7465 static void calc_global_load_remove(struct rq
*rq
)
7467 atomic_long_sub(rq
->calc_load_active
, &calc_load_tasks
);
7468 rq
->calc_load_active
= 0;
7470 #endif /* CONFIG_HOTPLUG_CPU */
7472 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
7474 static struct ctl_table sd_ctl_dir
[] = {
7476 .procname
= "sched_domain",
7482 static struct ctl_table sd_ctl_root
[] = {
7484 .procname
= "kernel",
7486 .child
= sd_ctl_dir
,
7491 static struct ctl_table
*sd_alloc_ctl_entry(int n
)
7493 struct ctl_table
*entry
=
7494 kcalloc(n
, sizeof(struct ctl_table
), GFP_KERNEL
);
7499 static void sd_free_ctl_entry(struct ctl_table
**tablep
)
7501 struct ctl_table
*entry
;
7504 * In the intermediate directories, both the child directory and
7505 * procname are dynamically allocated and could fail but the mode
7506 * will always be set. In the lowest directory the names are
7507 * static strings and all have proc handlers.
7509 for (entry
= *tablep
; entry
->mode
; entry
++) {
7511 sd_free_ctl_entry(&entry
->child
);
7512 if (entry
->proc_handler
== NULL
)
7513 kfree(entry
->procname
);
7521 set_table_entry(struct ctl_table
*entry
,
7522 const char *procname
, void *data
, int maxlen
,
7523 mode_t mode
, proc_handler
*proc_handler
)
7525 entry
->procname
= procname
;
7527 entry
->maxlen
= maxlen
;
7529 entry
->proc_handler
= proc_handler
;
7532 static struct ctl_table
*
7533 sd_alloc_ctl_domain_table(struct sched_domain
*sd
)
7535 struct ctl_table
*table
= sd_alloc_ctl_entry(13);
7540 set_table_entry(&table
[0], "min_interval", &sd
->min_interval
,
7541 sizeof(long), 0644, proc_doulongvec_minmax
);
7542 set_table_entry(&table
[1], "max_interval", &sd
->max_interval
,
7543 sizeof(long), 0644, proc_doulongvec_minmax
);
7544 set_table_entry(&table
[2], "busy_idx", &sd
->busy_idx
,
7545 sizeof(int), 0644, proc_dointvec_minmax
);
7546 set_table_entry(&table
[3], "idle_idx", &sd
->idle_idx
,
7547 sizeof(int), 0644, proc_dointvec_minmax
);
7548 set_table_entry(&table
[4], "newidle_idx", &sd
->newidle_idx
,
7549 sizeof(int), 0644, proc_dointvec_minmax
);
7550 set_table_entry(&table
[5], "wake_idx", &sd
->wake_idx
,
7551 sizeof(int), 0644, proc_dointvec_minmax
);
7552 set_table_entry(&table
[6], "forkexec_idx", &sd
->forkexec_idx
,
7553 sizeof(int), 0644, proc_dointvec_minmax
);
7554 set_table_entry(&table
[7], "busy_factor", &sd
->busy_factor
,
7555 sizeof(int), 0644, proc_dointvec_minmax
);
7556 set_table_entry(&table
[8], "imbalance_pct", &sd
->imbalance_pct
,
7557 sizeof(int), 0644, proc_dointvec_minmax
);
7558 set_table_entry(&table
[9], "cache_nice_tries",
7559 &sd
->cache_nice_tries
,
7560 sizeof(int), 0644, proc_dointvec_minmax
);
7561 set_table_entry(&table
[10], "flags", &sd
->flags
,
7562 sizeof(int), 0644, proc_dointvec_minmax
);
7563 set_table_entry(&table
[11], "name", sd
->name
,
7564 CORENAME_MAX_SIZE
, 0444, proc_dostring
);
7565 /* &table[12] is terminator */
7570 static ctl_table
*sd_alloc_ctl_cpu_table(int cpu
)
7572 struct ctl_table
*entry
, *table
;
7573 struct sched_domain
*sd
;
7574 int domain_num
= 0, i
;
7577 for_each_domain(cpu
, sd
)
7579 entry
= table
= sd_alloc_ctl_entry(domain_num
+ 1);
7584 for_each_domain(cpu
, sd
) {
7585 snprintf(buf
, 32, "domain%d", i
);
7586 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
7588 entry
->child
= sd_alloc_ctl_domain_table(sd
);
7595 static struct ctl_table_header
*sd_sysctl_header
;
7596 static void register_sched_domain_sysctl(void)
7598 int i
, cpu_num
= num_possible_cpus();
7599 struct ctl_table
*entry
= sd_alloc_ctl_entry(cpu_num
+ 1);
7602 WARN_ON(sd_ctl_dir
[0].child
);
7603 sd_ctl_dir
[0].child
= entry
;
7608 for_each_possible_cpu(i
) {
7609 snprintf(buf
, 32, "cpu%d", i
);
7610 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
7612 entry
->child
= sd_alloc_ctl_cpu_table(i
);
7616 WARN_ON(sd_sysctl_header
);
7617 sd_sysctl_header
= register_sysctl_table(sd_ctl_root
);
7620 /* may be called multiple times per register */
7621 static void unregister_sched_domain_sysctl(void)
7623 if (sd_sysctl_header
)
7624 unregister_sysctl_table(sd_sysctl_header
);
7625 sd_sysctl_header
= NULL
;
7626 if (sd_ctl_dir
[0].child
)
7627 sd_free_ctl_entry(&sd_ctl_dir
[0].child
);
7630 static void register_sched_domain_sysctl(void)
7633 static void unregister_sched_domain_sysctl(void)
7638 static void set_rq_online(struct rq
*rq
)
7641 const struct sched_class
*class;
7643 cpumask_set_cpu(rq
->cpu
, rq
->rd
->online
);
7646 for_each_class(class) {
7647 if (class->rq_online
)
7648 class->rq_online(rq
);
7653 static void set_rq_offline(struct rq
*rq
)
7656 const struct sched_class
*class;
7658 for_each_class(class) {
7659 if (class->rq_offline
)
7660 class->rq_offline(rq
);
7663 cpumask_clear_cpu(rq
->cpu
, rq
->rd
->online
);
7669 * migration_call - callback that gets triggered when a CPU is added.
7670 * Here we can start up the necessary migration thread for the new CPU.
7672 static int __cpuinit
7673 migration_call(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
7675 struct task_struct
*p
;
7676 int cpu
= (long)hcpu
;
7677 unsigned long flags
;
7682 case CPU_UP_PREPARE
:
7683 case CPU_UP_PREPARE_FROZEN
:
7684 p
= kthread_create(migration_thread
, hcpu
, "migration/%d", cpu
);
7687 kthread_bind(p
, cpu
);
7688 /* Must be high prio: stop_machine expects to yield to it. */
7689 rq
= task_rq_lock(p
, &flags
);
7690 __setscheduler(rq
, p
, SCHED_FIFO
, MAX_RT_PRIO
-1);
7691 task_rq_unlock(rq
, &flags
);
7693 cpu_rq(cpu
)->migration_thread
= p
;
7694 rq
->calc_load_update
= calc_load_update
;
7698 case CPU_ONLINE_FROZEN
:
7699 /* Strictly unnecessary, as first user will wake it. */
7700 wake_up_process(cpu_rq(cpu
)->migration_thread
);
7702 /* Update our root-domain */
7704 raw_spin_lock_irqsave(&rq
->lock
, flags
);
7706 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
7710 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
7713 #ifdef CONFIG_HOTPLUG_CPU
7714 case CPU_UP_CANCELED
:
7715 case CPU_UP_CANCELED_FROZEN
:
7716 if (!cpu_rq(cpu
)->migration_thread
)
7718 /* Unbind it from offline cpu so it can run. Fall thru. */
7719 kthread_bind(cpu_rq(cpu
)->migration_thread
,
7720 cpumask_any(cpu_online_mask
));
7721 kthread_stop(cpu_rq(cpu
)->migration_thread
);
7722 put_task_struct(cpu_rq(cpu
)->migration_thread
);
7723 cpu_rq(cpu
)->migration_thread
= NULL
;
7727 case CPU_DEAD_FROZEN
:
7728 cpuset_lock(); /* around calls to cpuset_cpus_allowed_lock() */
7729 migrate_live_tasks(cpu
);
7731 kthread_stop(rq
->migration_thread
);
7732 put_task_struct(rq
->migration_thread
);
7733 rq
->migration_thread
= NULL
;
7734 /* Idle task back to normal (off runqueue, low prio) */
7735 raw_spin_lock_irq(&rq
->lock
);
7736 update_rq_clock(rq
);
7737 deactivate_task(rq
, rq
->idle
, 0);
7738 __setscheduler(rq
, rq
->idle
, SCHED_NORMAL
, 0);
7739 rq
->idle
->sched_class
= &idle_sched_class
;
7740 migrate_dead_tasks(cpu
);
7741 raw_spin_unlock_irq(&rq
->lock
);
7743 migrate_nr_uninterruptible(rq
);
7744 BUG_ON(rq
->nr_running
!= 0);
7745 calc_global_load_remove(rq
);
7747 * No need to migrate the tasks: it was best-effort if
7748 * they didn't take sched_hotcpu_mutex. Just wake up
7751 raw_spin_lock_irq(&rq
->lock
);
7752 while (!list_empty(&rq
->migration_queue
)) {
7753 struct migration_req
*req
;
7755 req
= list_entry(rq
->migration_queue
.next
,
7756 struct migration_req
, list
);
7757 list_del_init(&req
->list
);
7758 raw_spin_unlock_irq(&rq
->lock
);
7759 complete(&req
->done
);
7760 raw_spin_lock_irq(&rq
->lock
);
7762 raw_spin_unlock_irq(&rq
->lock
);
7766 case CPU_DYING_FROZEN
:
7767 /* Update our root-domain */
7769 raw_spin_lock_irqsave(&rq
->lock
, flags
);
7771 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
7774 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
7782 * Register at high priority so that task migration (migrate_all_tasks)
7783 * happens before everything else. This has to be lower priority than
7784 * the notifier in the perf_event subsystem, though.
7786 static struct notifier_block __cpuinitdata migration_notifier
= {
7787 .notifier_call
= migration_call
,
7791 static int __init
migration_init(void)
7793 void *cpu
= (void *)(long)smp_processor_id();
7796 /* Start one for the boot CPU: */
7797 err
= migration_call(&migration_notifier
, CPU_UP_PREPARE
, cpu
);
7798 BUG_ON(err
== NOTIFY_BAD
);
7799 migration_call(&migration_notifier
, CPU_ONLINE
, cpu
);
7800 register_cpu_notifier(&migration_notifier
);
7804 early_initcall(migration_init
);
7809 #ifdef CONFIG_SCHED_DEBUG
7811 static __read_mostly
int sched_domain_debug_enabled
;
7813 static int __init
sched_domain_debug_setup(char *str
)
7815 sched_domain_debug_enabled
= 1;
7819 early_param("sched_debug", sched_domain_debug_setup
);
7821 static int sched_domain_debug_one(struct sched_domain
*sd
, int cpu
, int level
,
7822 struct cpumask
*groupmask
)
7824 struct sched_group
*group
= sd
->groups
;
7827 cpulist_scnprintf(str
, sizeof(str
), sched_domain_span(sd
));
7828 cpumask_clear(groupmask
);
7830 printk(KERN_DEBUG
"%*s domain %d: ", level
, "", level
);
7832 if (!(sd
->flags
& SD_LOAD_BALANCE
)) {
7833 pr_cont("does not load-balance\n");
7835 pr_err("ERROR: !SD_LOAD_BALANCE domain has parent\n");
7839 pr_cont("span %s level %s\n", str
, sd
->name
);
7841 if (!cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
7842 pr_err("ERROR: domain->span does not contain CPU%d\n", cpu
);
7844 if (!cpumask_test_cpu(cpu
, sched_group_cpus(group
))) {
7845 pr_err("ERROR: domain->groups does not contain CPU%d\n", cpu
);
7848 printk(KERN_DEBUG
"%*s groups:", level
+ 1, "");
7852 pr_err("ERROR: group is NULL\n");
7856 if (!group
->cpu_power
) {
7858 pr_err("ERROR: domain->cpu_power not set\n");
7862 if (!cpumask_weight(sched_group_cpus(group
))) {
7864 pr_err("ERROR: empty group\n");
7868 if (cpumask_intersects(groupmask
, sched_group_cpus(group
))) {
7870 pr_err("ERROR: repeated CPUs\n");
7874 cpumask_or(groupmask
, groupmask
, sched_group_cpus(group
));
7876 cpulist_scnprintf(str
, sizeof(str
), sched_group_cpus(group
));
7878 pr_cont(" %s", str
);
7879 if (group
->cpu_power
!= SCHED_LOAD_SCALE
) {
7880 pr_cont(" (cpu_power = %d)", group
->cpu_power
);
7883 group
= group
->next
;
7884 } while (group
!= sd
->groups
);
7887 if (!cpumask_equal(sched_domain_span(sd
), groupmask
))
7888 pr_err("ERROR: groups don't span domain->span\n");
7891 !cpumask_subset(groupmask
, sched_domain_span(sd
->parent
)))
7892 pr_err("ERROR: parent span is not a superset of domain->span\n");
7896 static void sched_domain_debug(struct sched_domain
*sd
, int cpu
)
7898 cpumask_var_t groupmask
;
7901 if (!sched_domain_debug_enabled
)
7905 printk(KERN_DEBUG
"CPU%d attaching NULL sched-domain.\n", cpu
);
7909 printk(KERN_DEBUG
"CPU%d attaching sched-domain:\n", cpu
);
7911 if (!alloc_cpumask_var(&groupmask
, GFP_KERNEL
)) {
7912 printk(KERN_DEBUG
"Cannot load-balance (out of memory)\n");
7917 if (sched_domain_debug_one(sd
, cpu
, level
, groupmask
))
7924 free_cpumask_var(groupmask
);
7926 #else /* !CONFIG_SCHED_DEBUG */
7927 # define sched_domain_debug(sd, cpu) do { } while (0)
7928 #endif /* CONFIG_SCHED_DEBUG */
7930 static int sd_degenerate(struct sched_domain
*sd
)
7932 if (cpumask_weight(sched_domain_span(sd
)) == 1)
7935 /* Following flags need at least 2 groups */
7936 if (sd
->flags
& (SD_LOAD_BALANCE
|
7937 SD_BALANCE_NEWIDLE
|
7941 SD_SHARE_PKG_RESOURCES
)) {
7942 if (sd
->groups
!= sd
->groups
->next
)
7946 /* Following flags don't use groups */
7947 if (sd
->flags
& (SD_WAKE_AFFINE
))
7954 sd_parent_degenerate(struct sched_domain
*sd
, struct sched_domain
*parent
)
7956 unsigned long cflags
= sd
->flags
, pflags
= parent
->flags
;
7958 if (sd_degenerate(parent
))
7961 if (!cpumask_equal(sched_domain_span(sd
), sched_domain_span(parent
)))
7964 /* Flags needing groups don't count if only 1 group in parent */
7965 if (parent
->groups
== parent
->groups
->next
) {
7966 pflags
&= ~(SD_LOAD_BALANCE
|
7967 SD_BALANCE_NEWIDLE
|
7971 SD_SHARE_PKG_RESOURCES
);
7972 if (nr_node_ids
== 1)
7973 pflags
&= ~SD_SERIALIZE
;
7975 if (~cflags
& pflags
)
7981 static void free_rootdomain(struct root_domain
*rd
)
7983 synchronize_sched();
7985 cpupri_cleanup(&rd
->cpupri
);
7987 free_cpumask_var(rd
->rto_mask
);
7988 free_cpumask_var(rd
->online
);
7989 free_cpumask_var(rd
->span
);
7993 static void rq_attach_root(struct rq
*rq
, struct root_domain
*rd
)
7995 struct root_domain
*old_rd
= NULL
;
7996 unsigned long flags
;
7998 raw_spin_lock_irqsave(&rq
->lock
, flags
);
8003 if (cpumask_test_cpu(rq
->cpu
, old_rd
->online
))
8006 cpumask_clear_cpu(rq
->cpu
, old_rd
->span
);
8009 * If we dont want to free the old_rt yet then
8010 * set old_rd to NULL to skip the freeing later
8013 if (!atomic_dec_and_test(&old_rd
->refcount
))
8017 atomic_inc(&rd
->refcount
);
8020 cpumask_set_cpu(rq
->cpu
, rd
->span
);
8021 if (cpumask_test_cpu(rq
->cpu
, cpu_active_mask
))
8024 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
8027 free_rootdomain(old_rd
);
8030 static int init_rootdomain(struct root_domain
*rd
, bool bootmem
)
8032 gfp_t gfp
= GFP_KERNEL
;
8034 memset(rd
, 0, sizeof(*rd
));
8039 if (!alloc_cpumask_var(&rd
->span
, gfp
))
8041 if (!alloc_cpumask_var(&rd
->online
, gfp
))
8043 if (!alloc_cpumask_var(&rd
->rto_mask
, gfp
))
8046 if (cpupri_init(&rd
->cpupri
, bootmem
) != 0)
8051 free_cpumask_var(rd
->rto_mask
);
8053 free_cpumask_var(rd
->online
);
8055 free_cpumask_var(rd
->span
);
8060 static void init_defrootdomain(void)
8062 init_rootdomain(&def_root_domain
, true);
8064 atomic_set(&def_root_domain
.refcount
, 1);
8067 static struct root_domain
*alloc_rootdomain(void)
8069 struct root_domain
*rd
;
8071 rd
= kmalloc(sizeof(*rd
), GFP_KERNEL
);
8075 if (init_rootdomain(rd
, false) != 0) {
8084 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
8085 * hold the hotplug lock.
8088 cpu_attach_domain(struct sched_domain
*sd
, struct root_domain
*rd
, int cpu
)
8090 struct rq
*rq
= cpu_rq(cpu
);
8091 struct sched_domain
*tmp
;
8093 /* Remove the sched domains which do not contribute to scheduling. */
8094 for (tmp
= sd
; tmp
; ) {
8095 struct sched_domain
*parent
= tmp
->parent
;
8099 if (sd_parent_degenerate(tmp
, parent
)) {
8100 tmp
->parent
= parent
->parent
;
8102 parent
->parent
->child
= tmp
;
8107 if (sd
&& sd_degenerate(sd
)) {
8113 sched_domain_debug(sd
, cpu
);
8115 rq_attach_root(rq
, rd
);
8116 rcu_assign_pointer(rq
->sd
, sd
);
8119 /* cpus with isolated domains */
8120 static cpumask_var_t cpu_isolated_map
;
8122 /* Setup the mask of cpus configured for isolated domains */
8123 static int __init
isolated_cpu_setup(char *str
)
8125 alloc_bootmem_cpumask_var(&cpu_isolated_map
);
8126 cpulist_parse(str
, cpu_isolated_map
);
8130 __setup("isolcpus=", isolated_cpu_setup
);
8133 * init_sched_build_groups takes the cpumask we wish to span, and a pointer
8134 * to a function which identifies what group(along with sched group) a CPU
8135 * belongs to. The return value of group_fn must be a >= 0 and < nr_cpu_ids
8136 * (due to the fact that we keep track of groups covered with a struct cpumask).
8138 * init_sched_build_groups will build a circular linked list of the groups
8139 * covered by the given span, and will set each group's ->cpumask correctly,
8140 * and ->cpu_power to 0.
8143 init_sched_build_groups(const struct cpumask
*span
,
8144 const struct cpumask
*cpu_map
,
8145 int (*group_fn
)(int cpu
, const struct cpumask
*cpu_map
,
8146 struct sched_group
**sg
,
8147 struct cpumask
*tmpmask
),
8148 struct cpumask
*covered
, struct cpumask
*tmpmask
)
8150 struct sched_group
*first
= NULL
, *last
= NULL
;
8153 cpumask_clear(covered
);
8155 for_each_cpu(i
, span
) {
8156 struct sched_group
*sg
;
8157 int group
= group_fn(i
, cpu_map
, &sg
, tmpmask
);
8160 if (cpumask_test_cpu(i
, covered
))
8163 cpumask_clear(sched_group_cpus(sg
));
8166 for_each_cpu(j
, span
) {
8167 if (group_fn(j
, cpu_map
, NULL
, tmpmask
) != group
)
8170 cpumask_set_cpu(j
, covered
);
8171 cpumask_set_cpu(j
, sched_group_cpus(sg
));
8182 #define SD_NODES_PER_DOMAIN 16
8187 * find_next_best_node - find the next node to include in a sched_domain
8188 * @node: node whose sched_domain we're building
8189 * @used_nodes: nodes already in the sched_domain
8191 * Find the next node to include in a given scheduling domain. Simply
8192 * finds the closest node not already in the @used_nodes map.
8194 * Should use nodemask_t.
8196 static int find_next_best_node(int node
, nodemask_t
*used_nodes
)
8198 int i
, n
, val
, min_val
, best_node
= 0;
8202 for (i
= 0; i
< nr_node_ids
; i
++) {
8203 /* Start at @node */
8204 n
= (node
+ i
) % nr_node_ids
;
8206 if (!nr_cpus_node(n
))
8209 /* Skip already used nodes */
8210 if (node_isset(n
, *used_nodes
))
8213 /* Simple min distance search */
8214 val
= node_distance(node
, n
);
8216 if (val
< min_val
) {
8222 node_set(best_node
, *used_nodes
);
8227 * sched_domain_node_span - get a cpumask for a node's sched_domain
8228 * @node: node whose cpumask we're constructing
8229 * @span: resulting cpumask
8231 * Given a node, construct a good cpumask for its sched_domain to span. It
8232 * should be one that prevents unnecessary balancing, but also spreads tasks
8235 static void sched_domain_node_span(int node
, struct cpumask
*span
)
8237 nodemask_t used_nodes
;
8240 cpumask_clear(span
);
8241 nodes_clear(used_nodes
);
8243 cpumask_or(span
, span
, cpumask_of_node(node
));
8244 node_set(node
, used_nodes
);
8246 for (i
= 1; i
< SD_NODES_PER_DOMAIN
; i
++) {
8247 int next_node
= find_next_best_node(node
, &used_nodes
);
8249 cpumask_or(span
, span
, cpumask_of_node(next_node
));
8252 #endif /* CONFIG_NUMA */
8254 int sched_smt_power_savings
= 0, sched_mc_power_savings
= 0;
8257 * The cpus mask in sched_group and sched_domain hangs off the end.
8259 * ( See the the comments in include/linux/sched.h:struct sched_group
8260 * and struct sched_domain. )
8262 struct static_sched_group
{
8263 struct sched_group sg
;
8264 DECLARE_BITMAP(cpus
, CONFIG_NR_CPUS
);
8267 struct static_sched_domain
{
8268 struct sched_domain sd
;
8269 DECLARE_BITMAP(span
, CONFIG_NR_CPUS
);
8275 cpumask_var_t domainspan
;
8276 cpumask_var_t covered
;
8277 cpumask_var_t notcovered
;
8279 cpumask_var_t nodemask
;
8280 cpumask_var_t this_sibling_map
;
8281 cpumask_var_t this_core_map
;
8282 cpumask_var_t send_covered
;
8283 cpumask_var_t tmpmask
;
8284 struct sched_group
**sched_group_nodes
;
8285 struct root_domain
*rd
;
8289 sa_sched_groups
= 0,
8294 sa_this_sibling_map
,
8296 sa_sched_group_nodes
,
8306 * SMT sched-domains:
8308 #ifdef CONFIG_SCHED_SMT
8309 static DEFINE_PER_CPU(struct static_sched_domain
, cpu_domains
);
8310 static DEFINE_PER_CPU(struct static_sched_group
, sched_groups
);
8313 cpu_to_cpu_group(int cpu
, const struct cpumask
*cpu_map
,
8314 struct sched_group
**sg
, struct cpumask
*unused
)
8317 *sg
= &per_cpu(sched_groups
, cpu
).sg
;
8320 #endif /* CONFIG_SCHED_SMT */
8323 * multi-core sched-domains:
8325 #ifdef CONFIG_SCHED_MC
8326 static DEFINE_PER_CPU(struct static_sched_domain
, core_domains
);
8327 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_core
);
8328 #endif /* CONFIG_SCHED_MC */
8330 #if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT)
8332 cpu_to_core_group(int cpu
, const struct cpumask
*cpu_map
,
8333 struct sched_group
**sg
, struct cpumask
*mask
)
8337 cpumask_and(mask
, topology_thread_cpumask(cpu
), cpu_map
);
8338 group
= cpumask_first(mask
);
8340 *sg
= &per_cpu(sched_group_core
, group
).sg
;
8343 #elif defined(CONFIG_SCHED_MC)
8345 cpu_to_core_group(int cpu
, const struct cpumask
*cpu_map
,
8346 struct sched_group
**sg
, struct cpumask
*unused
)
8349 *sg
= &per_cpu(sched_group_core
, cpu
).sg
;
8354 static DEFINE_PER_CPU(struct static_sched_domain
, phys_domains
);
8355 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_phys
);
8358 cpu_to_phys_group(int cpu
, const struct cpumask
*cpu_map
,
8359 struct sched_group
**sg
, struct cpumask
*mask
)
8362 #ifdef CONFIG_SCHED_MC
8363 cpumask_and(mask
, cpu_coregroup_mask(cpu
), cpu_map
);
8364 group
= cpumask_first(mask
);
8365 #elif defined(CONFIG_SCHED_SMT)
8366 cpumask_and(mask
, topology_thread_cpumask(cpu
), cpu_map
);
8367 group
= cpumask_first(mask
);
8372 *sg
= &per_cpu(sched_group_phys
, group
).sg
;
8378 * The init_sched_build_groups can't handle what we want to do with node
8379 * groups, so roll our own. Now each node has its own list of groups which
8380 * gets dynamically allocated.
8382 static DEFINE_PER_CPU(struct static_sched_domain
, node_domains
);
8383 static struct sched_group
***sched_group_nodes_bycpu
;
8385 static DEFINE_PER_CPU(struct static_sched_domain
, allnodes_domains
);
8386 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_allnodes
);
8388 static int cpu_to_allnodes_group(int cpu
, const struct cpumask
*cpu_map
,
8389 struct sched_group
**sg
,
8390 struct cpumask
*nodemask
)
8394 cpumask_and(nodemask
, cpumask_of_node(cpu_to_node(cpu
)), cpu_map
);
8395 group
= cpumask_first(nodemask
);
8398 *sg
= &per_cpu(sched_group_allnodes
, group
).sg
;
8402 static void init_numa_sched_groups_power(struct sched_group
*group_head
)
8404 struct sched_group
*sg
= group_head
;
8410 for_each_cpu(j
, sched_group_cpus(sg
)) {
8411 struct sched_domain
*sd
;
8413 sd
= &per_cpu(phys_domains
, j
).sd
;
8414 if (j
!= group_first_cpu(sd
->groups
)) {
8416 * Only add "power" once for each
8422 sg
->cpu_power
+= sd
->groups
->cpu_power
;
8425 } while (sg
!= group_head
);
8428 static int build_numa_sched_groups(struct s_data
*d
,
8429 const struct cpumask
*cpu_map
, int num
)
8431 struct sched_domain
*sd
;
8432 struct sched_group
*sg
, *prev
;
8435 cpumask_clear(d
->covered
);
8436 cpumask_and(d
->nodemask
, cpumask_of_node(num
), cpu_map
);
8437 if (cpumask_empty(d
->nodemask
)) {
8438 d
->sched_group_nodes
[num
] = NULL
;
8442 sched_domain_node_span(num
, d
->domainspan
);
8443 cpumask_and(d
->domainspan
, d
->domainspan
, cpu_map
);
8445 sg
= kmalloc_node(sizeof(struct sched_group
) + cpumask_size(),
8448 pr_warning("Can not alloc domain group for node %d\n", num
);
8451 d
->sched_group_nodes
[num
] = sg
;
8453 for_each_cpu(j
, d
->nodemask
) {
8454 sd
= &per_cpu(node_domains
, j
).sd
;
8459 cpumask_copy(sched_group_cpus(sg
), d
->nodemask
);
8461 cpumask_or(d
->covered
, d
->covered
, d
->nodemask
);
8464 for (j
= 0; j
< nr_node_ids
; j
++) {
8465 n
= (num
+ j
) % nr_node_ids
;
8466 cpumask_complement(d
->notcovered
, d
->covered
);
8467 cpumask_and(d
->tmpmask
, d
->notcovered
, cpu_map
);
8468 cpumask_and(d
->tmpmask
, d
->tmpmask
, d
->domainspan
);
8469 if (cpumask_empty(d
->tmpmask
))
8471 cpumask_and(d
->tmpmask
, d
->tmpmask
, cpumask_of_node(n
));
8472 if (cpumask_empty(d
->tmpmask
))
8474 sg
= kmalloc_node(sizeof(struct sched_group
) + cpumask_size(),
8477 pr_warning("Can not alloc domain group for node %d\n",
8482 cpumask_copy(sched_group_cpus(sg
), d
->tmpmask
);
8483 sg
->next
= prev
->next
;
8484 cpumask_or(d
->covered
, d
->covered
, d
->tmpmask
);
8491 #endif /* CONFIG_NUMA */
8494 /* Free memory allocated for various sched_group structures */
8495 static void free_sched_groups(const struct cpumask
*cpu_map
,
8496 struct cpumask
*nodemask
)
8500 for_each_cpu(cpu
, cpu_map
) {
8501 struct sched_group
**sched_group_nodes
8502 = sched_group_nodes_bycpu
[cpu
];
8504 if (!sched_group_nodes
)
8507 for (i
= 0; i
< nr_node_ids
; i
++) {
8508 struct sched_group
*oldsg
, *sg
= sched_group_nodes
[i
];
8510 cpumask_and(nodemask
, cpumask_of_node(i
), cpu_map
);
8511 if (cpumask_empty(nodemask
))
8521 if (oldsg
!= sched_group_nodes
[i
])
8524 kfree(sched_group_nodes
);
8525 sched_group_nodes_bycpu
[cpu
] = NULL
;
8528 #else /* !CONFIG_NUMA */
8529 static void free_sched_groups(const struct cpumask
*cpu_map
,
8530 struct cpumask
*nodemask
)
8533 #endif /* CONFIG_NUMA */
8536 * Initialize sched groups cpu_power.
8538 * cpu_power indicates the capacity of sched group, which is used while
8539 * distributing the load between different sched groups in a sched domain.
8540 * Typically cpu_power for all the groups in a sched domain will be same unless
8541 * there are asymmetries in the topology. If there are asymmetries, group
8542 * having more cpu_power will pickup more load compared to the group having
8545 static void init_sched_groups_power(int cpu
, struct sched_domain
*sd
)
8547 struct sched_domain
*child
;
8548 struct sched_group
*group
;
8552 WARN_ON(!sd
|| !sd
->groups
);
8554 if (cpu
!= group_first_cpu(sd
->groups
))
8559 sd
->groups
->cpu_power
= 0;
8562 power
= SCHED_LOAD_SCALE
;
8563 weight
= cpumask_weight(sched_domain_span(sd
));
8565 * SMT siblings share the power of a single core.
8566 * Usually multiple threads get a better yield out of
8567 * that one core than a single thread would have,
8568 * reflect that in sd->smt_gain.
8570 if ((sd
->flags
& SD_SHARE_CPUPOWER
) && weight
> 1) {
8571 power
*= sd
->smt_gain
;
8573 power
>>= SCHED_LOAD_SHIFT
;
8575 sd
->groups
->cpu_power
+= power
;
8580 * Add cpu_power of each child group to this groups cpu_power.
8582 group
= child
->groups
;
8584 sd
->groups
->cpu_power
+= group
->cpu_power
;
8585 group
= group
->next
;
8586 } while (group
!= child
->groups
);
8590 * Initializers for schedule domains
8591 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
8594 #ifdef CONFIG_SCHED_DEBUG
8595 # define SD_INIT_NAME(sd, type) sd->name = #type
8597 # define SD_INIT_NAME(sd, type) do { } while (0)
8600 #define SD_INIT(sd, type) sd_init_##type(sd)
8602 #define SD_INIT_FUNC(type) \
8603 static noinline void sd_init_##type(struct sched_domain *sd) \
8605 memset(sd, 0, sizeof(*sd)); \
8606 *sd = SD_##type##_INIT; \
8607 sd->level = SD_LV_##type; \
8608 SD_INIT_NAME(sd, type); \
8613 SD_INIT_FUNC(ALLNODES
)
8616 #ifdef CONFIG_SCHED_SMT
8617 SD_INIT_FUNC(SIBLING
)
8619 #ifdef CONFIG_SCHED_MC
8623 static int default_relax_domain_level
= -1;
8625 static int __init
setup_relax_domain_level(char *str
)
8629 val
= simple_strtoul(str
, NULL
, 0);
8630 if (val
< SD_LV_MAX
)
8631 default_relax_domain_level
= val
;
8635 __setup("relax_domain_level=", setup_relax_domain_level
);
8637 static void set_domain_attribute(struct sched_domain
*sd
,
8638 struct sched_domain_attr
*attr
)
8642 if (!attr
|| attr
->relax_domain_level
< 0) {
8643 if (default_relax_domain_level
< 0)
8646 request
= default_relax_domain_level
;
8648 request
= attr
->relax_domain_level
;
8649 if (request
< sd
->level
) {
8650 /* turn off idle balance on this domain */
8651 sd
->flags
&= ~(SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
8653 /* turn on idle balance on this domain */
8654 sd
->flags
|= (SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
8658 static void __free_domain_allocs(struct s_data
*d
, enum s_alloc what
,
8659 const struct cpumask
*cpu_map
)
8662 case sa_sched_groups
:
8663 free_sched_groups(cpu_map
, d
->tmpmask
); /* fall through */
8664 d
->sched_group_nodes
= NULL
;
8666 free_rootdomain(d
->rd
); /* fall through */
8668 free_cpumask_var(d
->tmpmask
); /* fall through */
8669 case sa_send_covered
:
8670 free_cpumask_var(d
->send_covered
); /* fall through */
8671 case sa_this_core_map
:
8672 free_cpumask_var(d
->this_core_map
); /* fall through */
8673 case sa_this_sibling_map
:
8674 free_cpumask_var(d
->this_sibling_map
); /* fall through */
8676 free_cpumask_var(d
->nodemask
); /* fall through */
8677 case sa_sched_group_nodes
:
8679 kfree(d
->sched_group_nodes
); /* fall through */
8681 free_cpumask_var(d
->notcovered
); /* fall through */
8683 free_cpumask_var(d
->covered
); /* fall through */
8685 free_cpumask_var(d
->domainspan
); /* fall through */
8692 static enum s_alloc
__visit_domain_allocation_hell(struct s_data
*d
,
8693 const struct cpumask
*cpu_map
)
8696 if (!alloc_cpumask_var(&d
->domainspan
, GFP_KERNEL
))
8698 if (!alloc_cpumask_var(&d
->covered
, GFP_KERNEL
))
8699 return sa_domainspan
;
8700 if (!alloc_cpumask_var(&d
->notcovered
, GFP_KERNEL
))
8702 /* Allocate the per-node list of sched groups */
8703 d
->sched_group_nodes
= kcalloc(nr_node_ids
,
8704 sizeof(struct sched_group
*), GFP_KERNEL
);
8705 if (!d
->sched_group_nodes
) {
8706 pr_warning("Can not alloc sched group node list\n");
8707 return sa_notcovered
;
8709 sched_group_nodes_bycpu
[cpumask_first(cpu_map
)] = d
->sched_group_nodes
;
8711 if (!alloc_cpumask_var(&d
->nodemask
, GFP_KERNEL
))
8712 return sa_sched_group_nodes
;
8713 if (!alloc_cpumask_var(&d
->this_sibling_map
, GFP_KERNEL
))
8715 if (!alloc_cpumask_var(&d
->this_core_map
, GFP_KERNEL
))
8716 return sa_this_sibling_map
;
8717 if (!alloc_cpumask_var(&d
->send_covered
, GFP_KERNEL
))
8718 return sa_this_core_map
;
8719 if (!alloc_cpumask_var(&d
->tmpmask
, GFP_KERNEL
))
8720 return sa_send_covered
;
8721 d
->rd
= alloc_rootdomain();
8723 pr_warning("Cannot alloc root domain\n");
8726 return sa_rootdomain
;
8729 static struct sched_domain
*__build_numa_sched_domains(struct s_data
*d
,
8730 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
, int i
)
8732 struct sched_domain
*sd
= NULL
;
8734 struct sched_domain
*parent
;
8737 if (cpumask_weight(cpu_map
) >
8738 SD_NODES_PER_DOMAIN
* cpumask_weight(d
->nodemask
)) {
8739 sd
= &per_cpu(allnodes_domains
, i
).sd
;
8740 SD_INIT(sd
, ALLNODES
);
8741 set_domain_attribute(sd
, attr
);
8742 cpumask_copy(sched_domain_span(sd
), cpu_map
);
8743 cpu_to_allnodes_group(i
, cpu_map
, &sd
->groups
, d
->tmpmask
);
8748 sd
= &per_cpu(node_domains
, i
).sd
;
8750 set_domain_attribute(sd
, attr
);
8751 sched_domain_node_span(cpu_to_node(i
), sched_domain_span(sd
));
8752 sd
->parent
= parent
;
8755 cpumask_and(sched_domain_span(sd
), sched_domain_span(sd
), cpu_map
);
8760 static struct sched_domain
*__build_cpu_sched_domain(struct s_data
*d
,
8761 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
,
8762 struct sched_domain
*parent
, int i
)
8764 struct sched_domain
*sd
;
8765 sd
= &per_cpu(phys_domains
, i
).sd
;
8767 set_domain_attribute(sd
, attr
);
8768 cpumask_copy(sched_domain_span(sd
), d
->nodemask
);
8769 sd
->parent
= parent
;
8772 cpu_to_phys_group(i
, cpu_map
, &sd
->groups
, d
->tmpmask
);
8776 static struct sched_domain
*__build_mc_sched_domain(struct s_data
*d
,
8777 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
,
8778 struct sched_domain
*parent
, int i
)
8780 struct sched_domain
*sd
= parent
;
8781 #ifdef CONFIG_SCHED_MC
8782 sd
= &per_cpu(core_domains
, i
).sd
;
8784 set_domain_attribute(sd
, attr
);
8785 cpumask_and(sched_domain_span(sd
), cpu_map
, cpu_coregroup_mask(i
));
8786 sd
->parent
= parent
;
8788 cpu_to_core_group(i
, cpu_map
, &sd
->groups
, d
->tmpmask
);
8793 static struct sched_domain
*__build_smt_sched_domain(struct s_data
*d
,
8794 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
,
8795 struct sched_domain
*parent
, int i
)
8797 struct sched_domain
*sd
= parent
;
8798 #ifdef CONFIG_SCHED_SMT
8799 sd
= &per_cpu(cpu_domains
, i
).sd
;
8800 SD_INIT(sd
, SIBLING
);
8801 set_domain_attribute(sd
, attr
);
8802 cpumask_and(sched_domain_span(sd
), cpu_map
, topology_thread_cpumask(i
));
8803 sd
->parent
= parent
;
8805 cpu_to_cpu_group(i
, cpu_map
, &sd
->groups
, d
->tmpmask
);
8810 static void build_sched_groups(struct s_data
*d
, enum sched_domain_level l
,
8811 const struct cpumask
*cpu_map
, int cpu
)
8814 #ifdef CONFIG_SCHED_SMT
8815 case SD_LV_SIBLING
: /* set up CPU (sibling) groups */
8816 cpumask_and(d
->this_sibling_map
, cpu_map
,
8817 topology_thread_cpumask(cpu
));
8818 if (cpu
== cpumask_first(d
->this_sibling_map
))
8819 init_sched_build_groups(d
->this_sibling_map
, cpu_map
,
8821 d
->send_covered
, d
->tmpmask
);
8824 #ifdef CONFIG_SCHED_MC
8825 case SD_LV_MC
: /* set up multi-core groups */
8826 cpumask_and(d
->this_core_map
, cpu_map
, cpu_coregroup_mask(cpu
));
8827 if (cpu
== cpumask_first(d
->this_core_map
))
8828 init_sched_build_groups(d
->this_core_map
, cpu_map
,
8830 d
->send_covered
, d
->tmpmask
);
8833 case SD_LV_CPU
: /* set up physical groups */
8834 cpumask_and(d
->nodemask
, cpumask_of_node(cpu
), cpu_map
);
8835 if (!cpumask_empty(d
->nodemask
))
8836 init_sched_build_groups(d
->nodemask
, cpu_map
,
8838 d
->send_covered
, d
->tmpmask
);
8841 case SD_LV_ALLNODES
:
8842 init_sched_build_groups(cpu_map
, cpu_map
, &cpu_to_allnodes_group
,
8843 d
->send_covered
, d
->tmpmask
);
8852 * Build sched domains for a given set of cpus and attach the sched domains
8853 * to the individual cpus
8855 static int __build_sched_domains(const struct cpumask
*cpu_map
,
8856 struct sched_domain_attr
*attr
)
8858 enum s_alloc alloc_state
= sa_none
;
8860 struct sched_domain
*sd
;
8866 alloc_state
= __visit_domain_allocation_hell(&d
, cpu_map
);
8867 if (alloc_state
!= sa_rootdomain
)
8869 alloc_state
= sa_sched_groups
;
8872 * Set up domains for cpus specified by the cpu_map.
8874 for_each_cpu(i
, cpu_map
) {
8875 cpumask_and(d
.nodemask
, cpumask_of_node(cpu_to_node(i
)),
8878 sd
= __build_numa_sched_domains(&d
, cpu_map
, attr
, i
);
8879 sd
= __build_cpu_sched_domain(&d
, cpu_map
, attr
, sd
, i
);
8880 sd
= __build_mc_sched_domain(&d
, cpu_map
, attr
, sd
, i
);
8881 sd
= __build_smt_sched_domain(&d
, cpu_map
, attr
, sd
, i
);
8884 for_each_cpu(i
, cpu_map
) {
8885 build_sched_groups(&d
, SD_LV_SIBLING
, cpu_map
, i
);
8886 build_sched_groups(&d
, SD_LV_MC
, cpu_map
, i
);
8889 /* Set up physical groups */
8890 for (i
= 0; i
< nr_node_ids
; i
++)
8891 build_sched_groups(&d
, SD_LV_CPU
, cpu_map
, i
);
8894 /* Set up node groups */
8896 build_sched_groups(&d
, SD_LV_ALLNODES
, cpu_map
, 0);
8898 for (i
= 0; i
< nr_node_ids
; i
++)
8899 if (build_numa_sched_groups(&d
, cpu_map
, i
))
8903 /* Calculate CPU power for physical packages and nodes */
8904 #ifdef CONFIG_SCHED_SMT
8905 for_each_cpu(i
, cpu_map
) {
8906 sd
= &per_cpu(cpu_domains
, i
).sd
;
8907 init_sched_groups_power(i
, sd
);
8910 #ifdef CONFIG_SCHED_MC
8911 for_each_cpu(i
, cpu_map
) {
8912 sd
= &per_cpu(core_domains
, i
).sd
;
8913 init_sched_groups_power(i
, sd
);
8917 for_each_cpu(i
, cpu_map
) {
8918 sd
= &per_cpu(phys_domains
, i
).sd
;
8919 init_sched_groups_power(i
, sd
);
8923 for (i
= 0; i
< nr_node_ids
; i
++)
8924 init_numa_sched_groups_power(d
.sched_group_nodes
[i
]);
8926 if (d
.sd_allnodes
) {
8927 struct sched_group
*sg
;
8929 cpu_to_allnodes_group(cpumask_first(cpu_map
), cpu_map
, &sg
,
8931 init_numa_sched_groups_power(sg
);
8935 /* Attach the domains */
8936 for_each_cpu(i
, cpu_map
) {
8937 #ifdef CONFIG_SCHED_SMT
8938 sd
= &per_cpu(cpu_domains
, i
).sd
;
8939 #elif defined(CONFIG_SCHED_MC)
8940 sd
= &per_cpu(core_domains
, i
).sd
;
8942 sd
= &per_cpu(phys_domains
, i
).sd
;
8944 cpu_attach_domain(sd
, d
.rd
, i
);
8947 d
.sched_group_nodes
= NULL
; /* don't free this we still need it */
8948 __free_domain_allocs(&d
, sa_tmpmask
, cpu_map
);
8952 __free_domain_allocs(&d
, alloc_state
, cpu_map
);
8956 static int build_sched_domains(const struct cpumask
*cpu_map
)
8958 return __build_sched_domains(cpu_map
, NULL
);
8961 static cpumask_var_t
*doms_cur
; /* current sched domains */
8962 static int ndoms_cur
; /* number of sched domains in 'doms_cur' */
8963 static struct sched_domain_attr
*dattr_cur
;
8964 /* attribues of custom domains in 'doms_cur' */
8967 * Special case: If a kmalloc of a doms_cur partition (array of
8968 * cpumask) fails, then fallback to a single sched domain,
8969 * as determined by the single cpumask fallback_doms.
8971 static cpumask_var_t fallback_doms
;
8974 * arch_update_cpu_topology lets virtualized architectures update the
8975 * cpu core maps. It is supposed to return 1 if the topology changed
8976 * or 0 if it stayed the same.
8978 int __attribute__((weak
)) arch_update_cpu_topology(void)
8983 cpumask_var_t
*alloc_sched_domains(unsigned int ndoms
)
8986 cpumask_var_t
*doms
;
8988 doms
= kmalloc(sizeof(*doms
) * ndoms
, GFP_KERNEL
);
8991 for (i
= 0; i
< ndoms
; i
++) {
8992 if (!alloc_cpumask_var(&doms
[i
], GFP_KERNEL
)) {
8993 free_sched_domains(doms
, i
);
9000 void free_sched_domains(cpumask_var_t doms
[], unsigned int ndoms
)
9003 for (i
= 0; i
< ndoms
; i
++)
9004 free_cpumask_var(doms
[i
]);
9009 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
9010 * For now this just excludes isolated cpus, but could be used to
9011 * exclude other special cases in the future.
9013 static int arch_init_sched_domains(const struct cpumask
*cpu_map
)
9017 arch_update_cpu_topology();
9019 doms_cur
= alloc_sched_domains(ndoms_cur
);
9021 doms_cur
= &fallback_doms
;
9022 cpumask_andnot(doms_cur
[0], cpu_map
, cpu_isolated_map
);
9024 err
= build_sched_domains(doms_cur
[0]);
9025 register_sched_domain_sysctl();
9030 static void arch_destroy_sched_domains(const struct cpumask
*cpu_map
,
9031 struct cpumask
*tmpmask
)
9033 free_sched_groups(cpu_map
, tmpmask
);
9037 * Detach sched domains from a group of cpus specified in cpu_map
9038 * These cpus will now be attached to the NULL domain
9040 static void detach_destroy_domains(const struct cpumask
*cpu_map
)
9042 /* Save because hotplug lock held. */
9043 static DECLARE_BITMAP(tmpmask
, CONFIG_NR_CPUS
);
9046 for_each_cpu(i
, cpu_map
)
9047 cpu_attach_domain(NULL
, &def_root_domain
, i
);
9048 synchronize_sched();
9049 arch_destroy_sched_domains(cpu_map
, to_cpumask(tmpmask
));
9052 /* handle null as "default" */
9053 static int dattrs_equal(struct sched_domain_attr
*cur
, int idx_cur
,
9054 struct sched_domain_attr
*new, int idx_new
)
9056 struct sched_domain_attr tmp
;
9063 return !memcmp(cur
? (cur
+ idx_cur
) : &tmp
,
9064 new ? (new + idx_new
) : &tmp
,
9065 sizeof(struct sched_domain_attr
));
9069 * Partition sched domains as specified by the 'ndoms_new'
9070 * cpumasks in the array doms_new[] of cpumasks. This compares
9071 * doms_new[] to the current sched domain partitioning, doms_cur[].
9072 * It destroys each deleted domain and builds each new domain.
9074 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'.
9075 * The masks don't intersect (don't overlap.) We should setup one
9076 * sched domain for each mask. CPUs not in any of the cpumasks will
9077 * not be load balanced. If the same cpumask appears both in the
9078 * current 'doms_cur' domains and in the new 'doms_new', we can leave
9081 * The passed in 'doms_new' should be allocated using
9082 * alloc_sched_domains. This routine takes ownership of it and will
9083 * free_sched_domains it when done with it. If the caller failed the
9084 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1,
9085 * and partition_sched_domains() will fallback to the single partition
9086 * 'fallback_doms', it also forces the domains to be rebuilt.
9088 * If doms_new == NULL it will be replaced with cpu_online_mask.
9089 * ndoms_new == 0 is a special case for destroying existing domains,
9090 * and it will not create the default domain.
9092 * Call with hotplug lock held
9094 void partition_sched_domains(int ndoms_new
, cpumask_var_t doms_new
[],
9095 struct sched_domain_attr
*dattr_new
)
9100 mutex_lock(&sched_domains_mutex
);
9102 /* always unregister in case we don't destroy any domains */
9103 unregister_sched_domain_sysctl();
9105 /* Let architecture update cpu core mappings. */
9106 new_topology
= arch_update_cpu_topology();
9108 n
= doms_new
? ndoms_new
: 0;
9110 /* Destroy deleted domains */
9111 for (i
= 0; i
< ndoms_cur
; i
++) {
9112 for (j
= 0; j
< n
&& !new_topology
; j
++) {
9113 if (cpumask_equal(doms_cur
[i
], doms_new
[j
])
9114 && dattrs_equal(dattr_cur
, i
, dattr_new
, j
))
9117 /* no match - a current sched domain not in new doms_new[] */
9118 detach_destroy_domains(doms_cur
[i
]);
9123 if (doms_new
== NULL
) {
9125 doms_new
= &fallback_doms
;
9126 cpumask_andnot(doms_new
[0], cpu_active_mask
, cpu_isolated_map
);
9127 WARN_ON_ONCE(dattr_new
);
9130 /* Build new domains */
9131 for (i
= 0; i
< ndoms_new
; i
++) {
9132 for (j
= 0; j
< ndoms_cur
&& !new_topology
; j
++) {
9133 if (cpumask_equal(doms_new
[i
], doms_cur
[j
])
9134 && dattrs_equal(dattr_new
, i
, dattr_cur
, j
))
9137 /* no match - add a new doms_new */
9138 __build_sched_domains(doms_new
[i
],
9139 dattr_new
? dattr_new
+ i
: NULL
);
9144 /* Remember the new sched domains */
9145 if (doms_cur
!= &fallback_doms
)
9146 free_sched_domains(doms_cur
, ndoms_cur
);
9147 kfree(dattr_cur
); /* kfree(NULL) is safe */
9148 doms_cur
= doms_new
;
9149 dattr_cur
= dattr_new
;
9150 ndoms_cur
= ndoms_new
;
9152 register_sched_domain_sysctl();
9154 mutex_unlock(&sched_domains_mutex
);
9157 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
9158 static void arch_reinit_sched_domains(void)
9162 /* Destroy domains first to force the rebuild */
9163 partition_sched_domains(0, NULL
, NULL
);
9165 rebuild_sched_domains();
9169 static ssize_t
sched_power_savings_store(const char *buf
, size_t count
, int smt
)
9171 unsigned int level
= 0;
9173 if (sscanf(buf
, "%u", &level
) != 1)
9177 * level is always be positive so don't check for
9178 * level < POWERSAVINGS_BALANCE_NONE which is 0
9179 * What happens on 0 or 1 byte write,
9180 * need to check for count as well?
9183 if (level
>= MAX_POWERSAVINGS_BALANCE_LEVELS
)
9187 sched_smt_power_savings
= level
;
9189 sched_mc_power_savings
= level
;
9191 arch_reinit_sched_domains();
9196 #ifdef CONFIG_SCHED_MC
9197 static ssize_t
sched_mc_power_savings_show(struct sysdev_class
*class,
9200 return sprintf(page
, "%u\n", sched_mc_power_savings
);
9202 static ssize_t
sched_mc_power_savings_store(struct sysdev_class
*class,
9203 const char *buf
, size_t count
)
9205 return sched_power_savings_store(buf
, count
, 0);
9207 static SYSDEV_CLASS_ATTR(sched_mc_power_savings
, 0644,
9208 sched_mc_power_savings_show
,
9209 sched_mc_power_savings_store
);
9212 #ifdef CONFIG_SCHED_SMT
9213 static ssize_t
sched_smt_power_savings_show(struct sysdev_class
*dev
,
9216 return sprintf(page
, "%u\n", sched_smt_power_savings
);
9218 static ssize_t
sched_smt_power_savings_store(struct sysdev_class
*dev
,
9219 const char *buf
, size_t count
)
9221 return sched_power_savings_store(buf
, count
, 1);
9223 static SYSDEV_CLASS_ATTR(sched_smt_power_savings
, 0644,
9224 sched_smt_power_savings_show
,
9225 sched_smt_power_savings_store
);
9228 int __init
sched_create_sysfs_power_savings_entries(struct sysdev_class
*cls
)
9232 #ifdef CONFIG_SCHED_SMT
9234 err
= sysfs_create_file(&cls
->kset
.kobj
,
9235 &attr_sched_smt_power_savings
.attr
);
9237 #ifdef CONFIG_SCHED_MC
9238 if (!err
&& mc_capable())
9239 err
= sysfs_create_file(&cls
->kset
.kobj
,
9240 &attr_sched_mc_power_savings
.attr
);
9244 #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
9246 #ifndef CONFIG_CPUSETS
9248 * Add online and remove offline CPUs from the scheduler domains.
9249 * When cpusets are enabled they take over this function.
9251 static int update_sched_domains(struct notifier_block
*nfb
,
9252 unsigned long action
, void *hcpu
)
9256 case CPU_ONLINE_FROZEN
:
9257 case CPU_DOWN_PREPARE
:
9258 case CPU_DOWN_PREPARE_FROZEN
:
9259 case CPU_DOWN_FAILED
:
9260 case CPU_DOWN_FAILED_FROZEN
:
9261 partition_sched_domains(1, NULL
, NULL
);
9270 static int update_runtime(struct notifier_block
*nfb
,
9271 unsigned long action
, void *hcpu
)
9273 int cpu
= (int)(long)hcpu
;
9276 case CPU_DOWN_PREPARE
:
9277 case CPU_DOWN_PREPARE_FROZEN
:
9278 disable_runtime(cpu_rq(cpu
));
9281 case CPU_DOWN_FAILED
:
9282 case CPU_DOWN_FAILED_FROZEN
:
9284 case CPU_ONLINE_FROZEN
:
9285 enable_runtime(cpu_rq(cpu
));
9293 void __init
sched_init_smp(void)
9295 cpumask_var_t non_isolated_cpus
;
9297 alloc_cpumask_var(&non_isolated_cpus
, GFP_KERNEL
);
9298 alloc_cpumask_var(&fallback_doms
, GFP_KERNEL
);
9300 #if defined(CONFIG_NUMA)
9301 sched_group_nodes_bycpu
= kzalloc(nr_cpu_ids
* sizeof(void **),
9303 BUG_ON(sched_group_nodes_bycpu
== NULL
);
9306 mutex_lock(&sched_domains_mutex
);
9307 arch_init_sched_domains(cpu_active_mask
);
9308 cpumask_andnot(non_isolated_cpus
, cpu_possible_mask
, cpu_isolated_map
);
9309 if (cpumask_empty(non_isolated_cpus
))
9310 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus
);
9311 mutex_unlock(&sched_domains_mutex
);
9314 #ifndef CONFIG_CPUSETS
9315 /* XXX: Theoretical race here - CPU may be hotplugged now */
9316 hotcpu_notifier(update_sched_domains
, 0);
9319 /* RT runtime code needs to handle some hotplug events */
9320 hotcpu_notifier(update_runtime
, 0);
9324 /* Move init over to a non-isolated CPU */
9325 if (set_cpus_allowed_ptr(current
, non_isolated_cpus
) < 0)
9327 sched_init_granularity();
9328 free_cpumask_var(non_isolated_cpus
);
9330 init_sched_rt_class();
9333 void __init
sched_init_smp(void)
9335 sched_init_granularity();
9337 #endif /* CONFIG_SMP */
9339 const_debug
unsigned int sysctl_timer_migration
= 1;
9341 int in_sched_functions(unsigned long addr
)
9343 return in_lock_functions(addr
) ||
9344 (addr
>= (unsigned long)__sched_text_start
9345 && addr
< (unsigned long)__sched_text_end
);
9348 static void init_cfs_rq(struct cfs_rq
*cfs_rq
, struct rq
*rq
)
9350 cfs_rq
->tasks_timeline
= RB_ROOT
;
9351 INIT_LIST_HEAD(&cfs_rq
->tasks
);
9352 #ifdef CONFIG_FAIR_GROUP_SCHED
9355 cfs_rq
->min_vruntime
= (u64
)(-(1LL << 20));
9358 static void init_rt_rq(struct rt_rq
*rt_rq
, struct rq
*rq
)
9360 struct rt_prio_array
*array
;
9363 array
= &rt_rq
->active
;
9364 for (i
= 0; i
< MAX_RT_PRIO
; i
++) {
9365 INIT_LIST_HEAD(array
->queue
+ i
);
9366 __clear_bit(i
, array
->bitmap
);
9368 /* delimiter for bitsearch: */
9369 __set_bit(MAX_RT_PRIO
, array
->bitmap
);
9371 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
9372 rt_rq
->highest_prio
.curr
= MAX_RT_PRIO
;
9374 rt_rq
->highest_prio
.next
= MAX_RT_PRIO
;
9378 rt_rq
->rt_nr_migratory
= 0;
9379 rt_rq
->overloaded
= 0;
9380 plist_head_init_raw(&rt_rq
->pushable_tasks
, &rq
->lock
);
9384 rt_rq
->rt_throttled
= 0;
9385 rt_rq
->rt_runtime
= 0;
9386 raw_spin_lock_init(&rt_rq
->rt_runtime_lock
);
9388 #ifdef CONFIG_RT_GROUP_SCHED
9389 rt_rq
->rt_nr_boosted
= 0;
9394 #ifdef CONFIG_FAIR_GROUP_SCHED
9395 static void init_tg_cfs_entry(struct task_group
*tg
, struct cfs_rq
*cfs_rq
,
9396 struct sched_entity
*se
, int cpu
, int add
,
9397 struct sched_entity
*parent
)
9399 struct rq
*rq
= cpu_rq(cpu
);
9400 tg
->cfs_rq
[cpu
] = cfs_rq
;
9401 init_cfs_rq(cfs_rq
, rq
);
9404 list_add(&cfs_rq
->leaf_cfs_rq_list
, &rq
->leaf_cfs_rq_list
);
9407 /* se could be NULL for init_task_group */
9412 se
->cfs_rq
= &rq
->cfs
;
9414 se
->cfs_rq
= parent
->my_q
;
9417 se
->load
.weight
= tg
->shares
;
9418 se
->load
.inv_weight
= 0;
9419 se
->parent
= parent
;
9423 #ifdef CONFIG_RT_GROUP_SCHED
9424 static void init_tg_rt_entry(struct task_group
*tg
, struct rt_rq
*rt_rq
,
9425 struct sched_rt_entity
*rt_se
, int cpu
, int add
,
9426 struct sched_rt_entity
*parent
)
9428 struct rq
*rq
= cpu_rq(cpu
);
9430 tg
->rt_rq
[cpu
] = rt_rq
;
9431 init_rt_rq(rt_rq
, rq
);
9433 rt_rq
->rt_se
= rt_se
;
9434 rt_rq
->rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
9436 list_add(&rt_rq
->leaf_rt_rq_list
, &rq
->leaf_rt_rq_list
);
9438 tg
->rt_se
[cpu
] = rt_se
;
9443 rt_se
->rt_rq
= &rq
->rt
;
9445 rt_se
->rt_rq
= parent
->my_q
;
9447 rt_se
->my_q
= rt_rq
;
9448 rt_se
->parent
= parent
;
9449 INIT_LIST_HEAD(&rt_se
->run_list
);
9453 void __init
sched_init(void)
9456 unsigned long alloc_size
= 0, ptr
;
9458 #ifdef CONFIG_FAIR_GROUP_SCHED
9459 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
9461 #ifdef CONFIG_RT_GROUP_SCHED
9462 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
9464 #ifdef CONFIG_USER_SCHED
9467 #ifdef CONFIG_CPUMASK_OFFSTACK
9468 alloc_size
+= num_possible_cpus() * cpumask_size();
9471 ptr
= (unsigned long)kzalloc(alloc_size
, GFP_NOWAIT
);
9473 #ifdef CONFIG_FAIR_GROUP_SCHED
9474 init_task_group
.se
= (struct sched_entity
**)ptr
;
9475 ptr
+= nr_cpu_ids
* sizeof(void **);
9477 init_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
9478 ptr
+= nr_cpu_ids
* sizeof(void **);
9480 #ifdef CONFIG_USER_SCHED
9481 root_task_group
.se
= (struct sched_entity
**)ptr
;
9482 ptr
+= nr_cpu_ids
* sizeof(void **);
9484 root_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
9485 ptr
+= nr_cpu_ids
* sizeof(void **);
9486 #endif /* CONFIG_USER_SCHED */
9487 #endif /* CONFIG_FAIR_GROUP_SCHED */
9488 #ifdef CONFIG_RT_GROUP_SCHED
9489 init_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
9490 ptr
+= nr_cpu_ids
* sizeof(void **);
9492 init_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
9493 ptr
+= nr_cpu_ids
* sizeof(void **);
9495 #ifdef CONFIG_USER_SCHED
9496 root_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
9497 ptr
+= nr_cpu_ids
* sizeof(void **);
9499 root_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
9500 ptr
+= nr_cpu_ids
* sizeof(void **);
9501 #endif /* CONFIG_USER_SCHED */
9502 #endif /* CONFIG_RT_GROUP_SCHED */
9503 #ifdef CONFIG_CPUMASK_OFFSTACK
9504 for_each_possible_cpu(i
) {
9505 per_cpu(load_balance_tmpmask
, i
) = (void *)ptr
;
9506 ptr
+= cpumask_size();
9508 #endif /* CONFIG_CPUMASK_OFFSTACK */
9512 init_defrootdomain();
9515 init_rt_bandwidth(&def_rt_bandwidth
,
9516 global_rt_period(), global_rt_runtime());
9518 #ifdef CONFIG_RT_GROUP_SCHED
9519 init_rt_bandwidth(&init_task_group
.rt_bandwidth
,
9520 global_rt_period(), global_rt_runtime());
9521 #ifdef CONFIG_USER_SCHED
9522 init_rt_bandwidth(&root_task_group
.rt_bandwidth
,
9523 global_rt_period(), RUNTIME_INF
);
9524 #endif /* CONFIG_USER_SCHED */
9525 #endif /* CONFIG_RT_GROUP_SCHED */
9527 #ifdef CONFIG_GROUP_SCHED
9528 list_add(&init_task_group
.list
, &task_groups
);
9529 INIT_LIST_HEAD(&init_task_group
.children
);
9531 #ifdef CONFIG_USER_SCHED
9532 INIT_LIST_HEAD(&root_task_group
.children
);
9533 init_task_group
.parent
= &root_task_group
;
9534 list_add(&init_task_group
.siblings
, &root_task_group
.children
);
9535 #endif /* CONFIG_USER_SCHED */
9536 #endif /* CONFIG_GROUP_SCHED */
9538 #if defined CONFIG_FAIR_GROUP_SCHED && defined CONFIG_SMP
9539 update_shares_data
= __alloc_percpu(nr_cpu_ids
* sizeof(unsigned long),
9540 __alignof__(unsigned long));
9542 for_each_possible_cpu(i
) {
9546 raw_spin_lock_init(&rq
->lock
);
9548 rq
->calc_load_active
= 0;
9549 rq
->calc_load_update
= jiffies
+ LOAD_FREQ
;
9550 init_cfs_rq(&rq
->cfs
, rq
);
9551 init_rt_rq(&rq
->rt
, rq
);
9552 #ifdef CONFIG_FAIR_GROUP_SCHED
9553 init_task_group
.shares
= init_task_group_load
;
9554 INIT_LIST_HEAD(&rq
->leaf_cfs_rq_list
);
9555 #ifdef CONFIG_CGROUP_SCHED
9557 * How much cpu bandwidth does init_task_group get?
9559 * In case of task-groups formed thr' the cgroup filesystem, it
9560 * gets 100% of the cpu resources in the system. This overall
9561 * system cpu resource is divided among the tasks of
9562 * init_task_group and its child task-groups in a fair manner,
9563 * based on each entity's (task or task-group's) weight
9564 * (se->load.weight).
9566 * In other words, if init_task_group has 10 tasks of weight
9567 * 1024) and two child groups A0 and A1 (of weight 1024 each),
9568 * then A0's share of the cpu resource is:
9570 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
9572 * We achieve this by letting init_task_group's tasks sit
9573 * directly in rq->cfs (i.e init_task_group->se[] = NULL).
9575 init_tg_cfs_entry(&init_task_group
, &rq
->cfs
, NULL
, i
, 1, NULL
);
9576 #elif defined CONFIG_USER_SCHED
9577 root_task_group
.shares
= NICE_0_LOAD
;
9578 init_tg_cfs_entry(&root_task_group
, &rq
->cfs
, NULL
, i
, 0, NULL
);
9580 * In case of task-groups formed thr' the user id of tasks,
9581 * init_task_group represents tasks belonging to root user.
9582 * Hence it forms a sibling of all subsequent groups formed.
9583 * In this case, init_task_group gets only a fraction of overall
9584 * system cpu resource, based on the weight assigned to root
9585 * user's cpu share (INIT_TASK_GROUP_LOAD). This is accomplished
9586 * by letting tasks of init_task_group sit in a separate cfs_rq
9587 * (init_tg_cfs_rq) and having one entity represent this group of
9588 * tasks in rq->cfs (i.e init_task_group->se[] != NULL).
9590 init_tg_cfs_entry(&init_task_group
,
9591 &per_cpu(init_tg_cfs_rq
, i
),
9592 &per_cpu(init_sched_entity
, i
), i
, 1,
9593 root_task_group
.se
[i
]);
9596 #endif /* CONFIG_FAIR_GROUP_SCHED */
9598 rq
->rt
.rt_runtime
= def_rt_bandwidth
.rt_runtime
;
9599 #ifdef CONFIG_RT_GROUP_SCHED
9600 INIT_LIST_HEAD(&rq
->leaf_rt_rq_list
);
9601 #ifdef CONFIG_CGROUP_SCHED
9602 init_tg_rt_entry(&init_task_group
, &rq
->rt
, NULL
, i
, 1, NULL
);
9603 #elif defined CONFIG_USER_SCHED
9604 init_tg_rt_entry(&root_task_group
, &rq
->rt
, NULL
, i
, 0, NULL
);
9605 init_tg_rt_entry(&init_task_group
,
9606 &per_cpu(init_rt_rq_var
, i
),
9607 &per_cpu(init_sched_rt_entity
, i
), i
, 1,
9608 root_task_group
.rt_se
[i
]);
9612 for (j
= 0; j
< CPU_LOAD_IDX_MAX
; j
++)
9613 rq
->cpu_load
[j
] = 0;
9617 rq
->post_schedule
= 0;
9618 rq
->active_balance
= 0;
9619 rq
->next_balance
= jiffies
;
9623 rq
->migration_thread
= NULL
;
9625 rq
->avg_idle
= 2*sysctl_sched_migration_cost
;
9626 INIT_LIST_HEAD(&rq
->migration_queue
);
9627 rq_attach_root(rq
, &def_root_domain
);
9630 atomic_set(&rq
->nr_iowait
, 0);
9633 set_load_weight(&init_task
);
9635 #ifdef CONFIG_PREEMPT_NOTIFIERS
9636 INIT_HLIST_HEAD(&init_task
.preempt_notifiers
);
9640 open_softirq(SCHED_SOFTIRQ
, run_rebalance_domains
);
9643 #ifdef CONFIG_RT_MUTEXES
9644 plist_head_init_raw(&init_task
.pi_waiters
, &init_task
.pi_lock
);
9648 * The boot idle thread does lazy MMU switching as well:
9650 atomic_inc(&init_mm
.mm_count
);
9651 enter_lazy_tlb(&init_mm
, current
);
9654 * Make us the idle thread. Technically, schedule() should not be
9655 * called from this thread, however somewhere below it might be,
9656 * but because we are the idle thread, we just pick up running again
9657 * when this runqueue becomes "idle".
9659 init_idle(current
, smp_processor_id());
9661 calc_load_update
= jiffies
+ LOAD_FREQ
;
9664 * During early bootup we pretend to be a normal task:
9666 current
->sched_class
= &fair_sched_class
;
9668 /* Allocate the nohz_cpu_mask if CONFIG_CPUMASK_OFFSTACK */
9669 zalloc_cpumask_var(&nohz_cpu_mask
, GFP_NOWAIT
);
9672 zalloc_cpumask_var(&nohz
.cpu_mask
, GFP_NOWAIT
);
9673 alloc_cpumask_var(&nohz
.ilb_grp_nohz_mask
, GFP_NOWAIT
);
9675 /* May be allocated at isolcpus cmdline parse time */
9676 if (cpu_isolated_map
== NULL
)
9677 zalloc_cpumask_var(&cpu_isolated_map
, GFP_NOWAIT
);
9682 scheduler_running
= 1;
9685 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
9686 static inline int preempt_count_equals(int preempt_offset
)
9688 int nested
= preempt_count() & ~PREEMPT_ACTIVE
;
9690 return (nested
== PREEMPT_INATOMIC_BASE
+ preempt_offset
);
9693 void __might_sleep(char *file
, int line
, int preempt_offset
)
9696 static unsigned long prev_jiffy
; /* ratelimiting */
9698 if ((preempt_count_equals(preempt_offset
) && !irqs_disabled()) ||
9699 system_state
!= SYSTEM_RUNNING
|| oops_in_progress
)
9701 if (time_before(jiffies
, prev_jiffy
+ HZ
) && prev_jiffy
)
9703 prev_jiffy
= jiffies
;
9705 pr_err("BUG: sleeping function called from invalid context at %s:%d\n",
9707 pr_err("in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
9708 in_atomic(), irqs_disabled(),
9709 current
->pid
, current
->comm
);
9711 debug_show_held_locks(current
);
9712 if (irqs_disabled())
9713 print_irqtrace_events(current
);
9717 EXPORT_SYMBOL(__might_sleep
);
9720 #ifdef CONFIG_MAGIC_SYSRQ
9721 static void normalize_task(struct rq
*rq
, struct task_struct
*p
)
9725 update_rq_clock(rq
);
9726 on_rq
= p
->se
.on_rq
;
9728 deactivate_task(rq
, p
, 0);
9729 __setscheduler(rq
, p
, SCHED_NORMAL
, 0);
9731 activate_task(rq
, p
, 0);
9732 resched_task(rq
->curr
);
9736 void normalize_rt_tasks(void)
9738 struct task_struct
*g
, *p
;
9739 unsigned long flags
;
9742 read_lock_irqsave(&tasklist_lock
, flags
);
9743 do_each_thread(g
, p
) {
9745 * Only normalize user tasks:
9750 p
->se
.exec_start
= 0;
9751 #ifdef CONFIG_SCHEDSTATS
9752 p
->se
.wait_start
= 0;
9753 p
->se
.sleep_start
= 0;
9754 p
->se
.block_start
= 0;
9759 * Renice negative nice level userspace
9762 if (TASK_NICE(p
) < 0 && p
->mm
)
9763 set_user_nice(p
, 0);
9767 raw_spin_lock(&p
->pi_lock
);
9768 rq
= __task_rq_lock(p
);
9770 normalize_task(rq
, p
);
9772 __task_rq_unlock(rq
);
9773 raw_spin_unlock(&p
->pi_lock
);
9774 } while_each_thread(g
, p
);
9776 read_unlock_irqrestore(&tasklist_lock
, flags
);
9779 #endif /* CONFIG_MAGIC_SYSRQ */
9783 * These functions are only useful for the IA64 MCA handling.
9785 * They can only be called when the whole system has been
9786 * stopped - every CPU needs to be quiescent, and no scheduling
9787 * activity can take place. Using them for anything else would
9788 * be a serious bug, and as a result, they aren't even visible
9789 * under any other configuration.
9793 * curr_task - return the current task for a given cpu.
9794 * @cpu: the processor in question.
9796 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
9798 struct task_struct
*curr_task(int cpu
)
9800 return cpu_curr(cpu
);
9804 * set_curr_task - set the current task for a given cpu.
9805 * @cpu: the processor in question.
9806 * @p: the task pointer to set.
9808 * Description: This function must only be used when non-maskable interrupts
9809 * are serviced on a separate stack. It allows the architecture to switch the
9810 * notion of the current task on a cpu in a non-blocking manner. This function
9811 * must be called with all CPU's synchronized, and interrupts disabled, the
9812 * and caller must save the original value of the current task (see
9813 * curr_task() above) and restore that value before reenabling interrupts and
9814 * re-starting the system.
9816 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
9818 void set_curr_task(int cpu
, struct task_struct
*p
)
9825 #ifdef CONFIG_FAIR_GROUP_SCHED
9826 static void free_fair_sched_group(struct task_group
*tg
)
9830 for_each_possible_cpu(i
) {
9832 kfree(tg
->cfs_rq
[i
]);
9842 int alloc_fair_sched_group(struct task_group
*tg
, struct task_group
*parent
)
9844 struct cfs_rq
*cfs_rq
;
9845 struct sched_entity
*se
;
9849 tg
->cfs_rq
= kzalloc(sizeof(cfs_rq
) * nr_cpu_ids
, GFP_KERNEL
);
9852 tg
->se
= kzalloc(sizeof(se
) * nr_cpu_ids
, GFP_KERNEL
);
9856 tg
->shares
= NICE_0_LOAD
;
9858 for_each_possible_cpu(i
) {
9861 cfs_rq
= kzalloc_node(sizeof(struct cfs_rq
),
9862 GFP_KERNEL
, cpu_to_node(i
));
9866 se
= kzalloc_node(sizeof(struct sched_entity
),
9867 GFP_KERNEL
, cpu_to_node(i
));
9871 init_tg_cfs_entry(tg
, cfs_rq
, se
, i
, 0, parent
->se
[i
]);
9882 static inline void register_fair_sched_group(struct task_group
*tg
, int cpu
)
9884 list_add_rcu(&tg
->cfs_rq
[cpu
]->leaf_cfs_rq_list
,
9885 &cpu_rq(cpu
)->leaf_cfs_rq_list
);
9888 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
9890 list_del_rcu(&tg
->cfs_rq
[cpu
]->leaf_cfs_rq_list
);
9892 #else /* !CONFG_FAIR_GROUP_SCHED */
9893 static inline void free_fair_sched_group(struct task_group
*tg
)
9898 int alloc_fair_sched_group(struct task_group
*tg
, struct task_group
*parent
)
9903 static inline void register_fair_sched_group(struct task_group
*tg
, int cpu
)
9907 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
9910 #endif /* CONFIG_FAIR_GROUP_SCHED */
9912 #ifdef CONFIG_RT_GROUP_SCHED
9913 static void free_rt_sched_group(struct task_group
*tg
)
9917 destroy_rt_bandwidth(&tg
->rt_bandwidth
);
9919 for_each_possible_cpu(i
) {
9921 kfree(tg
->rt_rq
[i
]);
9923 kfree(tg
->rt_se
[i
]);
9931 int alloc_rt_sched_group(struct task_group
*tg
, struct task_group
*parent
)
9933 struct rt_rq
*rt_rq
;
9934 struct sched_rt_entity
*rt_se
;
9938 tg
->rt_rq
= kzalloc(sizeof(rt_rq
) * nr_cpu_ids
, GFP_KERNEL
);
9941 tg
->rt_se
= kzalloc(sizeof(rt_se
) * nr_cpu_ids
, GFP_KERNEL
);
9945 init_rt_bandwidth(&tg
->rt_bandwidth
,
9946 ktime_to_ns(def_rt_bandwidth
.rt_period
), 0);
9948 for_each_possible_cpu(i
) {
9951 rt_rq
= kzalloc_node(sizeof(struct rt_rq
),
9952 GFP_KERNEL
, cpu_to_node(i
));
9956 rt_se
= kzalloc_node(sizeof(struct sched_rt_entity
),
9957 GFP_KERNEL
, cpu_to_node(i
));
9961 init_tg_rt_entry(tg
, rt_rq
, rt_se
, i
, 0, parent
->rt_se
[i
]);
9972 static inline void register_rt_sched_group(struct task_group
*tg
, int cpu
)
9974 list_add_rcu(&tg
->rt_rq
[cpu
]->leaf_rt_rq_list
,
9975 &cpu_rq(cpu
)->leaf_rt_rq_list
);
9978 static inline void unregister_rt_sched_group(struct task_group
*tg
, int cpu
)
9980 list_del_rcu(&tg
->rt_rq
[cpu
]->leaf_rt_rq_list
);
9982 #else /* !CONFIG_RT_GROUP_SCHED */
9983 static inline void free_rt_sched_group(struct task_group
*tg
)
9988 int alloc_rt_sched_group(struct task_group
*tg
, struct task_group
*parent
)
9993 static inline void register_rt_sched_group(struct task_group
*tg
, int cpu
)
9997 static inline void unregister_rt_sched_group(struct task_group
*tg
, int cpu
)
10000 #endif /* CONFIG_RT_GROUP_SCHED */
10002 #ifdef CONFIG_GROUP_SCHED
10003 static void free_sched_group(struct task_group
*tg
)
10005 free_fair_sched_group(tg
);
10006 free_rt_sched_group(tg
);
10010 /* allocate runqueue etc for a new task group */
10011 struct task_group
*sched_create_group(struct task_group
*parent
)
10013 struct task_group
*tg
;
10014 unsigned long flags
;
10017 tg
= kzalloc(sizeof(*tg
), GFP_KERNEL
);
10019 return ERR_PTR(-ENOMEM
);
10021 if (!alloc_fair_sched_group(tg
, parent
))
10024 if (!alloc_rt_sched_group(tg
, parent
))
10027 spin_lock_irqsave(&task_group_lock
, flags
);
10028 for_each_possible_cpu(i
) {
10029 register_fair_sched_group(tg
, i
);
10030 register_rt_sched_group(tg
, i
);
10032 list_add_rcu(&tg
->list
, &task_groups
);
10034 WARN_ON(!parent
); /* root should already exist */
10036 tg
->parent
= parent
;
10037 INIT_LIST_HEAD(&tg
->children
);
10038 list_add_rcu(&tg
->siblings
, &parent
->children
);
10039 spin_unlock_irqrestore(&task_group_lock
, flags
);
10044 free_sched_group(tg
);
10045 return ERR_PTR(-ENOMEM
);
10048 /* rcu callback to free various structures associated with a task group */
10049 static void free_sched_group_rcu(struct rcu_head
*rhp
)
10051 /* now it should be safe to free those cfs_rqs */
10052 free_sched_group(container_of(rhp
, struct task_group
, rcu
));
10055 /* Destroy runqueue etc associated with a task group */
10056 void sched_destroy_group(struct task_group
*tg
)
10058 unsigned long flags
;
10061 spin_lock_irqsave(&task_group_lock
, flags
);
10062 for_each_possible_cpu(i
) {
10063 unregister_fair_sched_group(tg
, i
);
10064 unregister_rt_sched_group(tg
, i
);
10066 list_del_rcu(&tg
->list
);
10067 list_del_rcu(&tg
->siblings
);
10068 spin_unlock_irqrestore(&task_group_lock
, flags
);
10070 /* wait for possible concurrent references to cfs_rqs complete */
10071 call_rcu(&tg
->rcu
, free_sched_group_rcu
);
10074 /* change task's runqueue when it moves between groups.
10075 * The caller of this function should have put the task in its new group
10076 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
10077 * reflect its new group.
10079 void sched_move_task(struct task_struct
*tsk
)
10081 int on_rq
, running
;
10082 unsigned long flags
;
10085 rq
= task_rq_lock(tsk
, &flags
);
10087 update_rq_clock(rq
);
10089 running
= task_current(rq
, tsk
);
10090 on_rq
= tsk
->se
.on_rq
;
10093 dequeue_task(rq
, tsk
, 0);
10094 if (unlikely(running
))
10095 tsk
->sched_class
->put_prev_task(rq
, tsk
);
10097 set_task_rq(tsk
, task_cpu(tsk
));
10099 #ifdef CONFIG_FAIR_GROUP_SCHED
10100 if (tsk
->sched_class
->moved_group
)
10101 tsk
->sched_class
->moved_group(tsk
);
10104 if (unlikely(running
))
10105 tsk
->sched_class
->set_curr_task(rq
);
10107 enqueue_task(rq
, tsk
, 0);
10109 task_rq_unlock(rq
, &flags
);
10111 #endif /* CONFIG_GROUP_SCHED */
10113 #ifdef CONFIG_FAIR_GROUP_SCHED
10114 static void __set_se_shares(struct sched_entity
*se
, unsigned long shares
)
10116 struct cfs_rq
*cfs_rq
= se
->cfs_rq
;
10121 dequeue_entity(cfs_rq
, se
, 0);
10123 se
->load
.weight
= shares
;
10124 se
->load
.inv_weight
= 0;
10127 enqueue_entity(cfs_rq
, se
, 0);
10130 static void set_se_shares(struct sched_entity
*se
, unsigned long shares
)
10132 struct cfs_rq
*cfs_rq
= se
->cfs_rq
;
10133 struct rq
*rq
= cfs_rq
->rq
;
10134 unsigned long flags
;
10136 raw_spin_lock_irqsave(&rq
->lock
, flags
);
10137 __set_se_shares(se
, shares
);
10138 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
10141 static DEFINE_MUTEX(shares_mutex
);
10143 int sched_group_set_shares(struct task_group
*tg
, unsigned long shares
)
10146 unsigned long flags
;
10149 * We can't change the weight of the root cgroup.
10154 if (shares
< MIN_SHARES
)
10155 shares
= MIN_SHARES
;
10156 else if (shares
> MAX_SHARES
)
10157 shares
= MAX_SHARES
;
10159 mutex_lock(&shares_mutex
);
10160 if (tg
->shares
== shares
)
10163 spin_lock_irqsave(&task_group_lock
, flags
);
10164 for_each_possible_cpu(i
)
10165 unregister_fair_sched_group(tg
, i
);
10166 list_del_rcu(&tg
->siblings
);
10167 spin_unlock_irqrestore(&task_group_lock
, flags
);
10169 /* wait for any ongoing reference to this group to finish */
10170 synchronize_sched();
10173 * Now we are free to modify the group's share on each cpu
10174 * w/o tripping rebalance_share or load_balance_fair.
10176 tg
->shares
= shares
;
10177 for_each_possible_cpu(i
) {
10179 * force a rebalance
10181 cfs_rq_set_shares(tg
->cfs_rq
[i
], 0);
10182 set_se_shares(tg
->se
[i
], shares
);
10186 * Enable load balance activity on this group, by inserting it back on
10187 * each cpu's rq->leaf_cfs_rq_list.
10189 spin_lock_irqsave(&task_group_lock
, flags
);
10190 for_each_possible_cpu(i
)
10191 register_fair_sched_group(tg
, i
);
10192 list_add_rcu(&tg
->siblings
, &tg
->parent
->children
);
10193 spin_unlock_irqrestore(&task_group_lock
, flags
);
10195 mutex_unlock(&shares_mutex
);
10199 unsigned long sched_group_shares(struct task_group
*tg
)
10205 #ifdef CONFIG_RT_GROUP_SCHED
10207 * Ensure that the real time constraints are schedulable.
10209 static DEFINE_MUTEX(rt_constraints_mutex
);
10211 static unsigned long to_ratio(u64 period
, u64 runtime
)
10213 if (runtime
== RUNTIME_INF
)
10216 return div64_u64(runtime
<< 20, period
);
10219 /* Must be called with tasklist_lock held */
10220 static inline int tg_has_rt_tasks(struct task_group
*tg
)
10222 struct task_struct
*g
, *p
;
10224 do_each_thread(g
, p
) {
10225 if (rt_task(p
) && rt_rq_of_se(&p
->rt
)->tg
== tg
)
10227 } while_each_thread(g
, p
);
10232 struct rt_schedulable_data
{
10233 struct task_group
*tg
;
10238 static int tg_schedulable(struct task_group
*tg
, void *data
)
10240 struct rt_schedulable_data
*d
= data
;
10241 struct task_group
*child
;
10242 unsigned long total
, sum
= 0;
10243 u64 period
, runtime
;
10245 period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
10246 runtime
= tg
->rt_bandwidth
.rt_runtime
;
10249 period
= d
->rt_period
;
10250 runtime
= d
->rt_runtime
;
10253 #ifdef CONFIG_USER_SCHED
10254 if (tg
== &root_task_group
) {
10255 period
= global_rt_period();
10256 runtime
= global_rt_runtime();
10261 * Cannot have more runtime than the period.
10263 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
10267 * Ensure we don't starve existing RT tasks.
10269 if (rt_bandwidth_enabled() && !runtime
&& tg_has_rt_tasks(tg
))
10272 total
= to_ratio(period
, runtime
);
10275 * Nobody can have more than the global setting allows.
10277 if (total
> to_ratio(global_rt_period(), global_rt_runtime()))
10281 * The sum of our children's runtime should not exceed our own.
10283 list_for_each_entry_rcu(child
, &tg
->children
, siblings
) {
10284 period
= ktime_to_ns(child
->rt_bandwidth
.rt_period
);
10285 runtime
= child
->rt_bandwidth
.rt_runtime
;
10287 if (child
== d
->tg
) {
10288 period
= d
->rt_period
;
10289 runtime
= d
->rt_runtime
;
10292 sum
+= to_ratio(period
, runtime
);
10301 static int __rt_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
)
10303 struct rt_schedulable_data data
= {
10305 .rt_period
= period
,
10306 .rt_runtime
= runtime
,
10309 return walk_tg_tree(tg_schedulable
, tg_nop
, &data
);
10312 static int tg_set_bandwidth(struct task_group
*tg
,
10313 u64 rt_period
, u64 rt_runtime
)
10317 mutex_lock(&rt_constraints_mutex
);
10318 read_lock(&tasklist_lock
);
10319 err
= __rt_schedulable(tg
, rt_period
, rt_runtime
);
10323 raw_spin_lock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
10324 tg
->rt_bandwidth
.rt_period
= ns_to_ktime(rt_period
);
10325 tg
->rt_bandwidth
.rt_runtime
= rt_runtime
;
10327 for_each_possible_cpu(i
) {
10328 struct rt_rq
*rt_rq
= tg
->rt_rq
[i
];
10330 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
10331 rt_rq
->rt_runtime
= rt_runtime
;
10332 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
10334 raw_spin_unlock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
10336 read_unlock(&tasklist_lock
);
10337 mutex_unlock(&rt_constraints_mutex
);
10342 int sched_group_set_rt_runtime(struct task_group
*tg
, long rt_runtime_us
)
10344 u64 rt_runtime
, rt_period
;
10346 rt_period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
10347 rt_runtime
= (u64
)rt_runtime_us
* NSEC_PER_USEC
;
10348 if (rt_runtime_us
< 0)
10349 rt_runtime
= RUNTIME_INF
;
10351 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
10354 long sched_group_rt_runtime(struct task_group
*tg
)
10358 if (tg
->rt_bandwidth
.rt_runtime
== RUNTIME_INF
)
10361 rt_runtime_us
= tg
->rt_bandwidth
.rt_runtime
;
10362 do_div(rt_runtime_us
, NSEC_PER_USEC
);
10363 return rt_runtime_us
;
10366 int sched_group_set_rt_period(struct task_group
*tg
, long rt_period_us
)
10368 u64 rt_runtime
, rt_period
;
10370 rt_period
= (u64
)rt_period_us
* NSEC_PER_USEC
;
10371 rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
10373 if (rt_period
== 0)
10376 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
10379 long sched_group_rt_period(struct task_group
*tg
)
10383 rt_period_us
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
10384 do_div(rt_period_us
, NSEC_PER_USEC
);
10385 return rt_period_us
;
10388 static int sched_rt_global_constraints(void)
10390 u64 runtime
, period
;
10393 if (sysctl_sched_rt_period
<= 0)
10396 runtime
= global_rt_runtime();
10397 period
= global_rt_period();
10400 * Sanity check on the sysctl variables.
10402 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
10405 mutex_lock(&rt_constraints_mutex
);
10406 read_lock(&tasklist_lock
);
10407 ret
= __rt_schedulable(NULL
, 0, 0);
10408 read_unlock(&tasklist_lock
);
10409 mutex_unlock(&rt_constraints_mutex
);
10414 int sched_rt_can_attach(struct task_group
*tg
, struct task_struct
*tsk
)
10416 /* Don't accept realtime tasks when there is no way for them to run */
10417 if (rt_task(tsk
) && tg
->rt_bandwidth
.rt_runtime
== 0)
10423 #else /* !CONFIG_RT_GROUP_SCHED */
10424 static int sched_rt_global_constraints(void)
10426 unsigned long flags
;
10429 if (sysctl_sched_rt_period
<= 0)
10433 * There's always some RT tasks in the root group
10434 * -- migration, kstopmachine etc..
10436 if (sysctl_sched_rt_runtime
== 0)
10439 raw_spin_lock_irqsave(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
10440 for_each_possible_cpu(i
) {
10441 struct rt_rq
*rt_rq
= &cpu_rq(i
)->rt
;
10443 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
10444 rt_rq
->rt_runtime
= global_rt_runtime();
10445 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
10447 raw_spin_unlock_irqrestore(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
10451 #endif /* CONFIG_RT_GROUP_SCHED */
10453 int sched_rt_handler(struct ctl_table
*table
, int write
,
10454 void __user
*buffer
, size_t *lenp
,
10458 int old_period
, old_runtime
;
10459 static DEFINE_MUTEX(mutex
);
10461 mutex_lock(&mutex
);
10462 old_period
= sysctl_sched_rt_period
;
10463 old_runtime
= sysctl_sched_rt_runtime
;
10465 ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
10467 if (!ret
&& write
) {
10468 ret
= sched_rt_global_constraints();
10470 sysctl_sched_rt_period
= old_period
;
10471 sysctl_sched_rt_runtime
= old_runtime
;
10473 def_rt_bandwidth
.rt_runtime
= global_rt_runtime();
10474 def_rt_bandwidth
.rt_period
=
10475 ns_to_ktime(global_rt_period());
10478 mutex_unlock(&mutex
);
10483 #ifdef CONFIG_CGROUP_SCHED
10485 /* return corresponding task_group object of a cgroup */
10486 static inline struct task_group
*cgroup_tg(struct cgroup
*cgrp
)
10488 return container_of(cgroup_subsys_state(cgrp
, cpu_cgroup_subsys_id
),
10489 struct task_group
, css
);
10492 static struct cgroup_subsys_state
*
10493 cpu_cgroup_create(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
10495 struct task_group
*tg
, *parent
;
10497 if (!cgrp
->parent
) {
10498 /* This is early initialization for the top cgroup */
10499 return &init_task_group
.css
;
10502 parent
= cgroup_tg(cgrp
->parent
);
10503 tg
= sched_create_group(parent
);
10505 return ERR_PTR(-ENOMEM
);
10511 cpu_cgroup_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
10513 struct task_group
*tg
= cgroup_tg(cgrp
);
10515 sched_destroy_group(tg
);
10519 cpu_cgroup_can_attach_task(struct cgroup
*cgrp
, struct task_struct
*tsk
)
10521 #ifdef CONFIG_RT_GROUP_SCHED
10522 if (!sched_rt_can_attach(cgroup_tg(cgrp
), tsk
))
10525 /* We don't support RT-tasks being in separate groups */
10526 if (tsk
->sched_class
!= &fair_sched_class
)
10533 cpu_cgroup_can_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
10534 struct task_struct
*tsk
, bool threadgroup
)
10536 int retval
= cpu_cgroup_can_attach_task(cgrp
, tsk
);
10540 struct task_struct
*c
;
10542 list_for_each_entry_rcu(c
, &tsk
->thread_group
, thread_group
) {
10543 retval
= cpu_cgroup_can_attach_task(cgrp
, c
);
10555 cpu_cgroup_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
10556 struct cgroup
*old_cont
, struct task_struct
*tsk
,
10559 sched_move_task(tsk
);
10561 struct task_struct
*c
;
10563 list_for_each_entry_rcu(c
, &tsk
->thread_group
, thread_group
) {
10564 sched_move_task(c
);
10570 #ifdef CONFIG_FAIR_GROUP_SCHED
10571 static int cpu_shares_write_u64(struct cgroup
*cgrp
, struct cftype
*cftype
,
10574 return sched_group_set_shares(cgroup_tg(cgrp
), shareval
);
10577 static u64
cpu_shares_read_u64(struct cgroup
*cgrp
, struct cftype
*cft
)
10579 struct task_group
*tg
= cgroup_tg(cgrp
);
10581 return (u64
) tg
->shares
;
10583 #endif /* CONFIG_FAIR_GROUP_SCHED */
10585 #ifdef CONFIG_RT_GROUP_SCHED
10586 static int cpu_rt_runtime_write(struct cgroup
*cgrp
, struct cftype
*cft
,
10589 return sched_group_set_rt_runtime(cgroup_tg(cgrp
), val
);
10592 static s64
cpu_rt_runtime_read(struct cgroup
*cgrp
, struct cftype
*cft
)
10594 return sched_group_rt_runtime(cgroup_tg(cgrp
));
10597 static int cpu_rt_period_write_uint(struct cgroup
*cgrp
, struct cftype
*cftype
,
10600 return sched_group_set_rt_period(cgroup_tg(cgrp
), rt_period_us
);
10603 static u64
cpu_rt_period_read_uint(struct cgroup
*cgrp
, struct cftype
*cft
)
10605 return sched_group_rt_period(cgroup_tg(cgrp
));
10607 #endif /* CONFIG_RT_GROUP_SCHED */
10609 static struct cftype cpu_files
[] = {
10610 #ifdef CONFIG_FAIR_GROUP_SCHED
10613 .read_u64
= cpu_shares_read_u64
,
10614 .write_u64
= cpu_shares_write_u64
,
10617 #ifdef CONFIG_RT_GROUP_SCHED
10619 .name
= "rt_runtime_us",
10620 .read_s64
= cpu_rt_runtime_read
,
10621 .write_s64
= cpu_rt_runtime_write
,
10624 .name
= "rt_period_us",
10625 .read_u64
= cpu_rt_period_read_uint
,
10626 .write_u64
= cpu_rt_period_write_uint
,
10631 static int cpu_cgroup_populate(struct cgroup_subsys
*ss
, struct cgroup
*cont
)
10633 return cgroup_add_files(cont
, ss
, cpu_files
, ARRAY_SIZE(cpu_files
));
10636 struct cgroup_subsys cpu_cgroup_subsys
= {
10638 .create
= cpu_cgroup_create
,
10639 .destroy
= cpu_cgroup_destroy
,
10640 .can_attach
= cpu_cgroup_can_attach
,
10641 .attach
= cpu_cgroup_attach
,
10642 .populate
= cpu_cgroup_populate
,
10643 .subsys_id
= cpu_cgroup_subsys_id
,
10647 #endif /* CONFIG_CGROUP_SCHED */
10649 #ifdef CONFIG_CGROUP_CPUACCT
10652 * CPU accounting code for task groups.
10654 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
10655 * (balbir@in.ibm.com).
10658 /* track cpu usage of a group of tasks and its child groups */
10660 struct cgroup_subsys_state css
;
10661 /* cpuusage holds pointer to a u64-type object on every cpu */
10663 struct percpu_counter cpustat
[CPUACCT_STAT_NSTATS
];
10664 struct cpuacct
*parent
;
10667 struct cgroup_subsys cpuacct_subsys
;
10669 /* return cpu accounting group corresponding to this container */
10670 static inline struct cpuacct
*cgroup_ca(struct cgroup
*cgrp
)
10672 return container_of(cgroup_subsys_state(cgrp
, cpuacct_subsys_id
),
10673 struct cpuacct
, css
);
10676 /* return cpu accounting group to which this task belongs */
10677 static inline struct cpuacct
*task_ca(struct task_struct
*tsk
)
10679 return container_of(task_subsys_state(tsk
, cpuacct_subsys_id
),
10680 struct cpuacct
, css
);
10683 /* create a new cpu accounting group */
10684 static struct cgroup_subsys_state
*cpuacct_create(
10685 struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
10687 struct cpuacct
*ca
= kzalloc(sizeof(*ca
), GFP_KERNEL
);
10693 ca
->cpuusage
= alloc_percpu(u64
);
10697 for (i
= 0; i
< CPUACCT_STAT_NSTATS
; i
++)
10698 if (percpu_counter_init(&ca
->cpustat
[i
], 0))
10699 goto out_free_counters
;
10702 ca
->parent
= cgroup_ca(cgrp
->parent
);
10708 percpu_counter_destroy(&ca
->cpustat
[i
]);
10709 free_percpu(ca
->cpuusage
);
10713 return ERR_PTR(-ENOMEM
);
10716 /* destroy an existing cpu accounting group */
10718 cpuacct_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
10720 struct cpuacct
*ca
= cgroup_ca(cgrp
);
10723 for (i
= 0; i
< CPUACCT_STAT_NSTATS
; i
++)
10724 percpu_counter_destroy(&ca
->cpustat
[i
]);
10725 free_percpu(ca
->cpuusage
);
10729 static u64
cpuacct_cpuusage_read(struct cpuacct
*ca
, int cpu
)
10731 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
10734 #ifndef CONFIG_64BIT
10736 * Take rq->lock to make 64-bit read safe on 32-bit platforms.
10738 raw_spin_lock_irq(&cpu_rq(cpu
)->lock
);
10740 raw_spin_unlock_irq(&cpu_rq(cpu
)->lock
);
10748 static void cpuacct_cpuusage_write(struct cpuacct
*ca
, int cpu
, u64 val
)
10750 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
10752 #ifndef CONFIG_64BIT
10754 * Take rq->lock to make 64-bit write safe on 32-bit platforms.
10756 raw_spin_lock_irq(&cpu_rq(cpu
)->lock
);
10758 raw_spin_unlock_irq(&cpu_rq(cpu
)->lock
);
10764 /* return total cpu usage (in nanoseconds) of a group */
10765 static u64
cpuusage_read(struct cgroup
*cgrp
, struct cftype
*cft
)
10767 struct cpuacct
*ca
= cgroup_ca(cgrp
);
10768 u64 totalcpuusage
= 0;
10771 for_each_present_cpu(i
)
10772 totalcpuusage
+= cpuacct_cpuusage_read(ca
, i
);
10774 return totalcpuusage
;
10777 static int cpuusage_write(struct cgroup
*cgrp
, struct cftype
*cftype
,
10780 struct cpuacct
*ca
= cgroup_ca(cgrp
);
10789 for_each_present_cpu(i
)
10790 cpuacct_cpuusage_write(ca
, i
, 0);
10796 static int cpuacct_percpu_seq_read(struct cgroup
*cgroup
, struct cftype
*cft
,
10797 struct seq_file
*m
)
10799 struct cpuacct
*ca
= cgroup_ca(cgroup
);
10803 for_each_present_cpu(i
) {
10804 percpu
= cpuacct_cpuusage_read(ca
, i
);
10805 seq_printf(m
, "%llu ", (unsigned long long) percpu
);
10807 seq_printf(m
, "\n");
10811 static const char *cpuacct_stat_desc
[] = {
10812 [CPUACCT_STAT_USER
] = "user",
10813 [CPUACCT_STAT_SYSTEM
] = "system",
10816 static int cpuacct_stats_show(struct cgroup
*cgrp
, struct cftype
*cft
,
10817 struct cgroup_map_cb
*cb
)
10819 struct cpuacct
*ca
= cgroup_ca(cgrp
);
10822 for (i
= 0; i
< CPUACCT_STAT_NSTATS
; i
++) {
10823 s64 val
= percpu_counter_read(&ca
->cpustat
[i
]);
10824 val
= cputime64_to_clock_t(val
);
10825 cb
->fill(cb
, cpuacct_stat_desc
[i
], val
);
10830 static struct cftype files
[] = {
10833 .read_u64
= cpuusage_read
,
10834 .write_u64
= cpuusage_write
,
10837 .name
= "usage_percpu",
10838 .read_seq_string
= cpuacct_percpu_seq_read
,
10842 .read_map
= cpuacct_stats_show
,
10846 static int cpuacct_populate(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
10848 return cgroup_add_files(cgrp
, ss
, files
, ARRAY_SIZE(files
));
10852 * charge this task's execution time to its accounting group.
10854 * called with rq->lock held.
10856 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
)
10858 struct cpuacct
*ca
;
10861 if (unlikely(!cpuacct_subsys
.active
))
10864 cpu
= task_cpu(tsk
);
10870 for (; ca
; ca
= ca
->parent
) {
10871 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
10872 *cpuusage
+= cputime
;
10879 * Charge the system/user time to the task's accounting group.
10881 static void cpuacct_update_stats(struct task_struct
*tsk
,
10882 enum cpuacct_stat_index idx
, cputime_t val
)
10884 struct cpuacct
*ca
;
10886 if (unlikely(!cpuacct_subsys
.active
))
10893 percpu_counter_add(&ca
->cpustat
[idx
], val
);
10899 struct cgroup_subsys cpuacct_subsys
= {
10901 .create
= cpuacct_create
,
10902 .destroy
= cpuacct_destroy
,
10903 .populate
= cpuacct_populate
,
10904 .subsys_id
= cpuacct_subsys_id
,
10906 #endif /* CONFIG_CGROUP_CPUACCT */
10910 int rcu_expedited_torture_stats(char *page
)
10914 EXPORT_SYMBOL_GPL(rcu_expedited_torture_stats
);
10916 void synchronize_sched_expedited(void)
10919 EXPORT_SYMBOL_GPL(synchronize_sched_expedited
);
10921 #else /* #ifndef CONFIG_SMP */
10923 static DEFINE_PER_CPU(struct migration_req
, rcu_migration_req
);
10924 static DEFINE_MUTEX(rcu_sched_expedited_mutex
);
10926 #define RCU_EXPEDITED_STATE_POST -2
10927 #define RCU_EXPEDITED_STATE_IDLE -1
10929 static int rcu_expedited_state
= RCU_EXPEDITED_STATE_IDLE
;
10931 int rcu_expedited_torture_stats(char *page
)
10936 cnt
+= sprintf(&page
[cnt
], "state: %d /", rcu_expedited_state
);
10937 for_each_online_cpu(cpu
) {
10938 cnt
+= sprintf(&page
[cnt
], " %d:%d",
10939 cpu
, per_cpu(rcu_migration_req
, cpu
).dest_cpu
);
10941 cnt
+= sprintf(&page
[cnt
], "\n");
10944 EXPORT_SYMBOL_GPL(rcu_expedited_torture_stats
);
10946 static long synchronize_sched_expedited_count
;
10949 * Wait for an rcu-sched grace period to elapse, but use "big hammer"
10950 * approach to force grace period to end quickly. This consumes
10951 * significant time on all CPUs, and is thus not recommended for
10952 * any sort of common-case code.
10954 * Note that it is illegal to call this function while holding any
10955 * lock that is acquired by a CPU-hotplug notifier. Failing to
10956 * observe this restriction will result in deadlock.
10958 void synchronize_sched_expedited(void)
10961 unsigned long flags
;
10962 bool need_full_sync
= 0;
10964 struct migration_req
*req
;
10968 smp_mb(); /* ensure prior mod happens before capturing snap. */
10969 snap
= ACCESS_ONCE(synchronize_sched_expedited_count
) + 1;
10971 while (!mutex_trylock(&rcu_sched_expedited_mutex
)) {
10973 if (trycount
++ < 10)
10974 udelay(trycount
* num_online_cpus());
10976 synchronize_sched();
10979 if (ACCESS_ONCE(synchronize_sched_expedited_count
) - snap
> 0) {
10980 smp_mb(); /* ensure test happens before caller kfree */
10985 rcu_expedited_state
= RCU_EXPEDITED_STATE_POST
;
10986 for_each_online_cpu(cpu
) {
10988 req
= &per_cpu(rcu_migration_req
, cpu
);
10989 init_completion(&req
->done
);
10991 req
->dest_cpu
= RCU_MIGRATION_NEED_QS
;
10992 raw_spin_lock_irqsave(&rq
->lock
, flags
);
10993 list_add(&req
->list
, &rq
->migration_queue
);
10994 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
10995 wake_up_process(rq
->migration_thread
);
10997 for_each_online_cpu(cpu
) {
10998 rcu_expedited_state
= cpu
;
10999 req
= &per_cpu(rcu_migration_req
, cpu
);
11001 wait_for_completion(&req
->done
);
11002 raw_spin_lock_irqsave(&rq
->lock
, flags
);
11003 if (unlikely(req
->dest_cpu
== RCU_MIGRATION_MUST_SYNC
))
11004 need_full_sync
= 1;
11005 req
->dest_cpu
= RCU_MIGRATION_IDLE
;
11006 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
11008 rcu_expedited_state
= RCU_EXPEDITED_STATE_IDLE
;
11009 synchronize_sched_expedited_count
++;
11010 mutex_unlock(&rcu_sched_expedited_mutex
);
11012 if (need_full_sync
)
11013 synchronize_sched();
11015 EXPORT_SYMBOL_GPL(synchronize_sched_expedited
);
11017 #endif /* #else #ifndef CONFIG_SMP */