4 * Kernel scheduler and related syscalls
6 * Copyright (C) 1991-2002 Linus Torvalds
8 * 1996-12-23 Modified by Dave Grothe to fix bugs in semaphores and
9 * make semaphores SMP safe
10 * 1998-11-19 Implemented schedule_timeout() and related stuff
12 * 2002-01-04 New ultra-scalable O(1) scheduler by Ingo Molnar:
13 * hybrid priority-list and round-robin design with
14 * an array-switch method of distributing timeslices
15 * and per-CPU runqueues. Cleanups and useful suggestions
16 * by Davide Libenzi, preemptible kernel bits by Robert Love.
17 * 2003-09-03 Interactivity tuning by Con Kolivas.
18 * 2004-04-02 Scheduler domains code by Nick Piggin
19 * 2007-04-15 Work begun on replacing all interactivity tuning with a
20 * fair scheduling design by Con Kolivas.
21 * 2007-05-05 Load balancing (smp-nice) and other improvements
23 * 2007-05-06 Interactivity improvements to CFS by Mike Galbraith
24 * 2007-07-01 Group scheduling enhancements by Srivatsa Vaddagiri
25 * 2007-11-29 RT balancing improvements by Steven Rostedt, Gregory Haskins,
26 * Thomas Gleixner, Mike Kravetz
30 #include <linux/module.h>
31 #include <linux/nmi.h>
32 #include <linux/init.h>
33 #include <linux/uaccess.h>
34 #include <linux/highmem.h>
35 #include <linux/smp_lock.h>
36 #include <asm/mmu_context.h>
37 #include <linux/interrupt.h>
38 #include <linux/capability.h>
39 #include <linux/completion.h>
40 #include <linux/kernel_stat.h>
41 #include <linux/debug_locks.h>
42 #include <linux/security.h>
43 #include <linux/notifier.h>
44 #include <linux/profile.h>
45 #include <linux/freezer.h>
46 #include <linux/vmalloc.h>
47 #include <linux/blkdev.h>
48 #include <linux/delay.h>
49 #include <linux/pid_namespace.h>
50 #include <linux/smp.h>
51 #include <linux/threads.h>
52 #include <linux/timer.h>
53 #include <linux/rcupdate.h>
54 #include <linux/cpu.h>
55 #include <linux/cpuset.h>
56 #include <linux/percpu.h>
57 #include <linux/kthread.h>
58 #include <linux/proc_fs.h>
59 #include <linux/seq_file.h>
60 #include <linux/sysctl.h>
61 #include <linux/syscalls.h>
62 #include <linux/times.h>
63 #include <linux/tsacct_kern.h>
64 #include <linux/kprobes.h>
65 #include <linux/delayacct.h>
66 #include <linux/reciprocal_div.h>
67 #include <linux/unistd.h>
68 #include <linux/pagemap.h>
69 #include <linux/hrtimer.h>
70 #include <linux/tick.h>
71 #include <linux/bootmem.h>
72 #include <linux/debugfs.h>
73 #include <linux/ctype.h>
74 #include <linux/ftrace.h>
75 #include <trace/sched.h>
78 #include <asm/irq_regs.h>
80 #include "sched_cpupri.h"
83 * Convert user-nice values [ -20 ... 0 ... 19 ]
84 * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
87 #define NICE_TO_PRIO(nice) (MAX_RT_PRIO + (nice) + 20)
88 #define PRIO_TO_NICE(prio) ((prio) - MAX_RT_PRIO - 20)
89 #define TASK_NICE(p) PRIO_TO_NICE((p)->static_prio)
92 * 'User priority' is the nice value converted to something we
93 * can work with better when scaling various scheduler parameters,
94 * it's a [ 0 ... 39 ] range.
96 #define USER_PRIO(p) ((p)-MAX_RT_PRIO)
97 #define TASK_USER_PRIO(p) USER_PRIO((p)->static_prio)
98 #define MAX_USER_PRIO (USER_PRIO(MAX_PRIO))
101 * Helpers for converting nanosecond timing to jiffy resolution
103 #define NS_TO_JIFFIES(TIME) ((unsigned long)(TIME) / (NSEC_PER_SEC / HZ))
105 #define NICE_0_LOAD SCHED_LOAD_SCALE
106 #define NICE_0_SHIFT SCHED_LOAD_SHIFT
109 * These are the 'tuning knobs' of the scheduler:
111 * default timeslice is 100 msecs (used only for SCHED_RR tasks).
112 * Timeslices get refilled after they expire.
114 #define DEF_TIMESLICE (100 * HZ / 1000)
117 * single value that denotes runtime == period, ie unlimited time.
119 #define RUNTIME_INF ((u64)~0ULL)
121 DEFINE_TRACE(sched_wait_task
);
122 DEFINE_TRACE(sched_wakeup
);
123 DEFINE_TRACE(sched_wakeup_new
);
124 DEFINE_TRACE(sched_switch
);
125 DEFINE_TRACE(sched_migrate_task
);
129 static void double_rq_lock(struct rq
*rq1
, struct rq
*rq2
);
132 * Divide a load by a sched group cpu_power : (load / sg->__cpu_power)
133 * Since cpu_power is a 'constant', we can use a reciprocal divide.
135 static inline u32
sg_div_cpu_power(const struct sched_group
*sg
, u32 load
)
137 return reciprocal_divide(load
, sg
->reciprocal_cpu_power
);
141 * Each time a sched group cpu_power is changed,
142 * we must compute its reciprocal value
144 static inline void sg_inc_cpu_power(struct sched_group
*sg
, u32 val
)
146 sg
->__cpu_power
+= val
;
147 sg
->reciprocal_cpu_power
= reciprocal_value(sg
->__cpu_power
);
151 static inline int rt_policy(int policy
)
153 if (unlikely(policy
== SCHED_FIFO
|| policy
== SCHED_RR
))
158 static inline int task_has_rt_policy(struct task_struct
*p
)
160 return rt_policy(p
->policy
);
164 * This is the priority-queue data structure of the RT scheduling class:
166 struct rt_prio_array
{
167 DECLARE_BITMAP(bitmap
, MAX_RT_PRIO
+1); /* include 1 bit for delimiter */
168 struct list_head queue
[MAX_RT_PRIO
];
171 struct rt_bandwidth
{
172 /* nests inside the rq lock: */
173 spinlock_t rt_runtime_lock
;
176 struct hrtimer rt_period_timer
;
179 static struct rt_bandwidth def_rt_bandwidth
;
181 static int do_sched_rt_period_timer(struct rt_bandwidth
*rt_b
, int overrun
);
183 static enum hrtimer_restart
sched_rt_period_timer(struct hrtimer
*timer
)
185 struct rt_bandwidth
*rt_b
=
186 container_of(timer
, struct rt_bandwidth
, rt_period_timer
);
192 now
= hrtimer_cb_get_time(timer
);
193 overrun
= hrtimer_forward(timer
, now
, rt_b
->rt_period
);
198 idle
= do_sched_rt_period_timer(rt_b
, overrun
);
201 return idle
? HRTIMER_NORESTART
: HRTIMER_RESTART
;
205 void init_rt_bandwidth(struct rt_bandwidth
*rt_b
, u64 period
, u64 runtime
)
207 rt_b
->rt_period
= ns_to_ktime(period
);
208 rt_b
->rt_runtime
= runtime
;
210 spin_lock_init(&rt_b
->rt_runtime_lock
);
212 hrtimer_init(&rt_b
->rt_period_timer
,
213 CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
214 rt_b
->rt_period_timer
.function
= sched_rt_period_timer
;
217 static inline int rt_bandwidth_enabled(void)
219 return sysctl_sched_rt_runtime
>= 0;
222 static void start_rt_bandwidth(struct rt_bandwidth
*rt_b
)
226 if (!rt_bandwidth_enabled() || rt_b
->rt_runtime
== RUNTIME_INF
)
229 if (hrtimer_active(&rt_b
->rt_period_timer
))
232 spin_lock(&rt_b
->rt_runtime_lock
);
237 if (hrtimer_active(&rt_b
->rt_period_timer
))
240 now
= hrtimer_cb_get_time(&rt_b
->rt_period_timer
);
241 hrtimer_forward(&rt_b
->rt_period_timer
, now
, rt_b
->rt_period
);
243 soft
= hrtimer_get_softexpires(&rt_b
->rt_period_timer
);
244 hard
= hrtimer_get_expires(&rt_b
->rt_period_timer
);
245 delta
= ktime_to_ns(ktime_sub(hard
, soft
));
246 __hrtimer_start_range_ns(&rt_b
->rt_period_timer
, soft
, delta
,
247 HRTIMER_MODE_ABS_PINNED
, 0);
249 spin_unlock(&rt_b
->rt_runtime_lock
);
252 #ifdef CONFIG_RT_GROUP_SCHED
253 static void destroy_rt_bandwidth(struct rt_bandwidth
*rt_b
)
255 hrtimer_cancel(&rt_b
->rt_period_timer
);
260 * sched_domains_mutex serializes calls to arch_init_sched_domains,
261 * detach_destroy_domains and partition_sched_domains.
263 static DEFINE_MUTEX(sched_domains_mutex
);
265 #ifdef CONFIG_GROUP_SCHED
267 #include <linux/cgroup.h>
271 static LIST_HEAD(task_groups
);
273 /* task group related information */
275 #ifdef CONFIG_CGROUP_SCHED
276 struct cgroup_subsys_state css
;
279 #ifdef CONFIG_USER_SCHED
283 #ifdef CONFIG_FAIR_GROUP_SCHED
284 /* schedulable entities of this group on each cpu */
285 struct sched_entity
**se
;
286 /* runqueue "owned" by this group on each cpu */
287 struct cfs_rq
**cfs_rq
;
288 unsigned long shares
;
291 #ifdef CONFIG_RT_GROUP_SCHED
292 struct sched_rt_entity
**rt_se
;
293 struct rt_rq
**rt_rq
;
295 struct rt_bandwidth rt_bandwidth
;
299 struct list_head list
;
301 struct task_group
*parent
;
302 struct list_head siblings
;
303 struct list_head children
;
306 #ifdef CONFIG_USER_SCHED
308 /* Helper function to pass uid information to create_sched_user() */
309 void set_tg_uid(struct user_struct
*user
)
311 user
->tg
->uid
= user
->uid
;
316 * Every UID task group (including init_task_group aka UID-0) will
317 * be a child to this group.
319 struct task_group root_task_group
;
321 #ifdef CONFIG_FAIR_GROUP_SCHED
322 /* Default task group's sched entity on each cpu */
323 static DEFINE_PER_CPU(struct sched_entity
, init_sched_entity
);
324 /* Default task group's cfs_rq on each cpu */
325 static DEFINE_PER_CPU(struct cfs_rq
, init_cfs_rq
) ____cacheline_aligned_in_smp
;
326 #endif /* CONFIG_FAIR_GROUP_SCHED */
328 #ifdef CONFIG_RT_GROUP_SCHED
329 static DEFINE_PER_CPU(struct sched_rt_entity
, init_sched_rt_entity
);
330 static DEFINE_PER_CPU(struct rt_rq
, init_rt_rq
) ____cacheline_aligned_in_smp
;
331 #endif /* CONFIG_RT_GROUP_SCHED */
332 #else /* !CONFIG_USER_SCHED */
333 #define root_task_group init_task_group
334 #endif /* CONFIG_USER_SCHED */
336 /* task_group_lock serializes add/remove of task groups and also changes to
337 * a task group's cpu shares.
339 static DEFINE_SPINLOCK(task_group_lock
);
342 static int root_task_group_empty(void)
344 return list_empty(&root_task_group
.children
);
348 #ifdef CONFIG_FAIR_GROUP_SCHED
349 #ifdef CONFIG_USER_SCHED
350 # define INIT_TASK_GROUP_LOAD (2*NICE_0_LOAD)
351 #else /* !CONFIG_USER_SCHED */
352 # define INIT_TASK_GROUP_LOAD NICE_0_LOAD
353 #endif /* CONFIG_USER_SCHED */
356 * A weight of 0 or 1 can cause arithmetics problems.
357 * A weight of a cfs_rq is the sum of weights of which entities
358 * are queued on this cfs_rq, so a weight of a entity should not be
359 * too large, so as the shares value of a task group.
360 * (The default weight is 1024 - so there's no practical
361 * limitation from this.)
364 #define MAX_SHARES (1UL << 18)
366 static int init_task_group_load
= INIT_TASK_GROUP_LOAD
;
369 /* Default task group.
370 * Every task in system belong to this group at bootup.
372 struct task_group init_task_group
;
374 /* return group to which a task belongs */
375 static inline struct task_group
*task_group(struct task_struct
*p
)
377 struct task_group
*tg
;
379 #ifdef CONFIG_USER_SCHED
381 tg
= __task_cred(p
)->user
->tg
;
383 #elif defined(CONFIG_CGROUP_SCHED)
384 tg
= container_of(task_subsys_state(p
, cpu_cgroup_subsys_id
),
385 struct task_group
, css
);
387 tg
= &init_task_group
;
392 /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
393 static inline void set_task_rq(struct task_struct
*p
, unsigned int cpu
)
395 #ifdef CONFIG_FAIR_GROUP_SCHED
396 p
->se
.cfs_rq
= task_group(p
)->cfs_rq
[cpu
];
397 p
->se
.parent
= task_group(p
)->se
[cpu
];
400 #ifdef CONFIG_RT_GROUP_SCHED
401 p
->rt
.rt_rq
= task_group(p
)->rt_rq
[cpu
];
402 p
->rt
.parent
= task_group(p
)->rt_se
[cpu
];
409 static int root_task_group_empty(void)
415 static inline void set_task_rq(struct task_struct
*p
, unsigned int cpu
) { }
416 static inline struct task_group
*task_group(struct task_struct
*p
)
421 #endif /* CONFIG_GROUP_SCHED */
423 /* CFS-related fields in a runqueue */
425 struct load_weight load
;
426 unsigned long nr_running
;
431 struct rb_root tasks_timeline
;
432 struct rb_node
*rb_leftmost
;
434 struct list_head tasks
;
435 struct list_head
*balance_iterator
;
438 * 'curr' points to currently running entity on this cfs_rq.
439 * It is set to NULL otherwise (i.e when none are currently running).
441 struct sched_entity
*curr
, *next
, *last
;
443 unsigned int nr_spread_over
;
445 #ifdef CONFIG_FAIR_GROUP_SCHED
446 struct rq
*rq
; /* cpu runqueue to which this cfs_rq is attached */
449 * leaf cfs_rqs are those that hold tasks (lowest schedulable entity in
450 * a hierarchy). Non-leaf lrqs hold other higher schedulable entities
451 * (like users, containers etc.)
453 * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This
454 * list is used during load balance.
456 struct list_head leaf_cfs_rq_list
;
457 struct task_group
*tg
; /* group that "owns" this runqueue */
461 * the part of load.weight contributed by tasks
463 unsigned long task_weight
;
466 * h_load = weight * f(tg)
468 * Where f(tg) is the recursive weight fraction assigned to
471 unsigned long h_load
;
474 * this cpu's part of tg->shares
476 unsigned long shares
;
479 * load.weight at the time we set shares
481 unsigned long rq_weight
;
486 /* Real-Time classes' related field in a runqueue: */
488 struct rt_prio_array active
;
489 unsigned long rt_nr_running
;
490 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
492 int curr
; /* highest queued rt task prio */
494 int next
; /* next highest */
499 unsigned long rt_nr_migratory
;
501 struct plist_head pushable_tasks
;
506 /* Nests inside the rq lock: */
507 spinlock_t rt_runtime_lock
;
509 #ifdef CONFIG_RT_GROUP_SCHED
510 unsigned long rt_nr_boosted
;
513 struct list_head leaf_rt_rq_list
;
514 struct task_group
*tg
;
515 struct sched_rt_entity
*rt_se
;
522 * We add the notion of a root-domain which will be used to define per-domain
523 * variables. Each exclusive cpuset essentially defines an island domain by
524 * fully partitioning the member cpus from any other cpuset. Whenever a new
525 * exclusive cpuset is created, we also create and attach a new root-domain
532 cpumask_var_t online
;
535 * The "RT overload" flag: it gets set if a CPU has more than
536 * one runnable RT task.
538 cpumask_var_t rto_mask
;
541 struct cpupri cpupri
;
543 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
545 * Preferred wake up cpu nominated by sched_mc balance that will be
546 * used when most cpus are idle in the system indicating overall very
547 * low system utilisation. Triggered at POWERSAVINGS_BALANCE_WAKEUP(2)
549 unsigned int sched_mc_preferred_wakeup_cpu
;
554 * By default the system creates a single root-domain with all cpus as
555 * members (mimicking the global state we have today).
557 static struct root_domain def_root_domain
;
562 * This is the main, per-CPU runqueue data structure.
564 * Locking rule: those places that want to lock multiple runqueues
565 * (such as the load balancing or the thread migration code), lock
566 * acquire operations must be ordered by ascending &runqueue.
573 * nr_running and cpu_load should be in the same cacheline because
574 * remote CPUs use both these fields when doing load calculation.
576 unsigned long nr_running
;
577 #define CPU_LOAD_IDX_MAX 5
578 unsigned long cpu_load
[CPU_LOAD_IDX_MAX
];
580 unsigned long last_tick_seen
;
581 unsigned char in_nohz_recently
;
583 /* capture load from *all* tasks on this cpu: */
584 struct load_weight load
;
585 unsigned long nr_load_updates
;
591 #ifdef CONFIG_FAIR_GROUP_SCHED
592 /* list of leaf cfs_rq on this cpu: */
593 struct list_head leaf_cfs_rq_list
;
595 #ifdef CONFIG_RT_GROUP_SCHED
596 struct list_head leaf_rt_rq_list
;
600 * This is part of a global counter where only the total sum
601 * over all CPUs matters. A task can increase this counter on
602 * one CPU and if it got migrated afterwards it may decrease
603 * it on another CPU. Always updated under the runqueue lock:
605 unsigned long nr_uninterruptible
;
607 struct task_struct
*curr
, *idle
;
608 unsigned long next_balance
;
609 struct mm_struct
*prev_mm
;
616 struct root_domain
*rd
;
617 struct sched_domain
*sd
;
619 unsigned char idle_at_tick
;
620 /* For active balancing */
623 /* cpu of this runqueue: */
627 unsigned long avg_load_per_task
;
629 struct task_struct
*migration_thread
;
630 struct list_head migration_queue
;
633 #ifdef CONFIG_SCHED_HRTICK
635 int hrtick_csd_pending
;
636 struct call_single_data hrtick_csd
;
638 struct hrtimer hrtick_timer
;
641 #ifdef CONFIG_SCHEDSTATS
643 struct sched_info rq_sched_info
;
644 unsigned long long rq_cpu_time
;
645 /* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */
647 /* sys_sched_yield() stats */
648 unsigned int yld_count
;
650 /* schedule() stats */
651 unsigned int sched_switch
;
652 unsigned int sched_count
;
653 unsigned int sched_goidle
;
655 /* try_to_wake_up() stats */
656 unsigned int ttwu_count
;
657 unsigned int ttwu_local
;
660 unsigned int bkl_count
;
664 static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq
, runqueues
);
666 static inline void check_preempt_curr(struct rq
*rq
, struct task_struct
*p
, int sync
)
668 rq
->curr
->sched_class
->check_preempt_curr(rq
, p
, sync
);
671 static inline int cpu_of(struct rq
*rq
)
681 * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
682 * See detach_destroy_domains: synchronize_sched for details.
684 * The domain tree of any CPU may only be accessed from within
685 * preempt-disabled sections.
687 #define for_each_domain(cpu, __sd) \
688 for (__sd = rcu_dereference(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent)
690 #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu)))
691 #define this_rq() (&__get_cpu_var(runqueues))
692 #define task_rq(p) cpu_rq(task_cpu(p))
693 #define cpu_curr(cpu) (cpu_rq(cpu)->curr)
695 static inline void update_rq_clock(struct rq
*rq
)
697 rq
->clock
= sched_clock_cpu(cpu_of(rq
));
701 * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
703 #ifdef CONFIG_SCHED_DEBUG
704 # define const_debug __read_mostly
706 # define const_debug static const
712 * Returns true if the current cpu runqueue is locked.
713 * This interface allows printk to be called with the runqueue lock
714 * held and know whether or not it is OK to wake up the klogd.
716 int runqueue_is_locked(void)
719 struct rq
*rq
= cpu_rq(cpu
);
722 ret
= spin_is_locked(&rq
->lock
);
728 * Debugging: various feature bits
731 #define SCHED_FEAT(name, enabled) \
732 __SCHED_FEAT_##name ,
735 #include "sched_features.h"
740 #define SCHED_FEAT(name, enabled) \
741 (1UL << __SCHED_FEAT_##name) * enabled |
743 const_debug
unsigned int sysctl_sched_features
=
744 #include "sched_features.h"
749 #ifdef CONFIG_SCHED_DEBUG
750 #define SCHED_FEAT(name, enabled) \
753 static __read_mostly
char *sched_feat_names
[] = {
754 #include "sched_features.h"
760 static int sched_feat_show(struct seq_file
*m
, void *v
)
764 for (i
= 0; sched_feat_names
[i
]; i
++) {
765 if (!(sysctl_sched_features
& (1UL << i
)))
767 seq_printf(m
, "%s ", sched_feat_names
[i
]);
775 sched_feat_write(struct file
*filp
, const char __user
*ubuf
,
776 size_t cnt
, loff_t
*ppos
)
786 if (copy_from_user(&buf
, ubuf
, cnt
))
791 if (strncmp(buf
, "NO_", 3) == 0) {
796 for (i
= 0; sched_feat_names
[i
]; i
++) {
797 int len
= strlen(sched_feat_names
[i
]);
799 if (strncmp(cmp
, sched_feat_names
[i
], len
) == 0) {
801 sysctl_sched_features
&= ~(1UL << i
);
803 sysctl_sched_features
|= (1UL << i
);
808 if (!sched_feat_names
[i
])
816 static int sched_feat_open(struct inode
*inode
, struct file
*filp
)
818 return single_open(filp
, sched_feat_show
, NULL
);
821 static struct file_operations sched_feat_fops
= {
822 .open
= sched_feat_open
,
823 .write
= sched_feat_write
,
826 .release
= single_release
,
829 static __init
int sched_init_debug(void)
831 debugfs_create_file("sched_features", 0644, NULL
, NULL
,
836 late_initcall(sched_init_debug
);
840 #define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
843 * Number of tasks to iterate in a single balance run.
844 * Limited because this is done with IRQs disabled.
846 const_debug
unsigned int sysctl_sched_nr_migrate
= 32;
849 * ratelimit for updating the group shares.
852 unsigned int sysctl_sched_shares_ratelimit
= 250000;
855 * Inject some fuzzyness into changing the per-cpu group shares
856 * this avoids remote rq-locks at the expense of fairness.
859 unsigned int sysctl_sched_shares_thresh
= 4;
862 * period over which we measure -rt task cpu usage in us.
865 unsigned int sysctl_sched_rt_period
= 1000000;
867 static __read_mostly
int scheduler_running
;
870 * part of the period that we allow rt tasks to run in us.
873 int sysctl_sched_rt_runtime
= 950000;
875 static inline u64
global_rt_period(void)
877 return (u64
)sysctl_sched_rt_period
* NSEC_PER_USEC
;
880 static inline u64
global_rt_runtime(void)
882 if (sysctl_sched_rt_runtime
< 0)
885 return (u64
)sysctl_sched_rt_runtime
* NSEC_PER_USEC
;
888 #ifndef prepare_arch_switch
889 # define prepare_arch_switch(next) do { } while (0)
891 #ifndef finish_arch_switch
892 # define finish_arch_switch(prev) do { } while (0)
895 static inline int task_current(struct rq
*rq
, struct task_struct
*p
)
897 return rq
->curr
== p
;
900 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
901 static inline int task_running(struct rq
*rq
, struct task_struct
*p
)
903 return task_current(rq
, p
);
906 static inline void prepare_lock_switch(struct rq
*rq
, struct task_struct
*next
)
910 static inline void finish_lock_switch(struct rq
*rq
, struct task_struct
*prev
)
912 #ifdef CONFIG_DEBUG_SPINLOCK
913 /* this is a valid case when another task releases the spinlock */
914 rq
->lock
.owner
= current
;
917 * If we are tracking spinlock dependencies then we have to
918 * fix up the runqueue lock - which gets 'carried over' from
921 spin_acquire(&rq
->lock
.dep_map
, 0, 0, _THIS_IP_
);
923 spin_unlock_irq(&rq
->lock
);
926 #else /* __ARCH_WANT_UNLOCKED_CTXSW */
927 static inline int task_running(struct rq
*rq
, struct task_struct
*p
)
932 return task_current(rq
, p
);
936 static inline void prepare_lock_switch(struct rq
*rq
, struct task_struct
*next
)
940 * We can optimise this out completely for !SMP, because the
941 * SMP rebalancing from interrupt is the only thing that cares
946 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
947 spin_unlock_irq(&rq
->lock
);
949 spin_unlock(&rq
->lock
);
953 static inline void finish_lock_switch(struct rq
*rq
, struct task_struct
*prev
)
957 * After ->oncpu is cleared, the task can be moved to a different CPU.
958 * We must ensure this doesn't happen until the switch is completely
964 #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW
968 #endif /* __ARCH_WANT_UNLOCKED_CTXSW */
971 * __task_rq_lock - lock the runqueue a given task resides on.
972 * Must be called interrupts disabled.
974 static inline struct rq
*__task_rq_lock(struct task_struct
*p
)
978 struct rq
*rq
= task_rq(p
);
979 spin_lock(&rq
->lock
);
980 if (likely(rq
== task_rq(p
)))
982 spin_unlock(&rq
->lock
);
987 * task_rq_lock - lock the runqueue a given task resides on and disable
988 * interrupts. Note the ordering: we can safely lookup the task_rq without
989 * explicitly disabling preemption.
991 static struct rq
*task_rq_lock(struct task_struct
*p
, unsigned long *flags
)
997 local_irq_save(*flags
);
999 spin_lock(&rq
->lock
);
1000 if (likely(rq
== task_rq(p
)))
1002 spin_unlock_irqrestore(&rq
->lock
, *flags
);
1006 void task_rq_unlock_wait(struct task_struct
*p
)
1008 struct rq
*rq
= task_rq(p
);
1010 smp_mb(); /* spin-unlock-wait is not a full memory barrier */
1011 spin_unlock_wait(&rq
->lock
);
1014 static void __task_rq_unlock(struct rq
*rq
)
1015 __releases(rq
->lock
)
1017 spin_unlock(&rq
->lock
);
1020 static inline void task_rq_unlock(struct rq
*rq
, unsigned long *flags
)
1021 __releases(rq
->lock
)
1023 spin_unlock_irqrestore(&rq
->lock
, *flags
);
1027 * this_rq_lock - lock this runqueue and disable interrupts.
1029 static struct rq
*this_rq_lock(void)
1030 __acquires(rq
->lock
)
1034 local_irq_disable();
1036 spin_lock(&rq
->lock
);
1041 #ifdef CONFIG_SCHED_HRTICK
1043 * Use HR-timers to deliver accurate preemption points.
1045 * Its all a bit involved since we cannot program an hrt while holding the
1046 * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
1049 * When we get rescheduled we reprogram the hrtick_timer outside of the
1055 * - enabled by features
1056 * - hrtimer is actually high res
1058 static inline int hrtick_enabled(struct rq
*rq
)
1060 if (!sched_feat(HRTICK
))
1062 if (!cpu_active(cpu_of(rq
)))
1064 return hrtimer_is_hres_active(&rq
->hrtick_timer
);
1067 static void hrtick_clear(struct rq
*rq
)
1069 if (hrtimer_active(&rq
->hrtick_timer
))
1070 hrtimer_cancel(&rq
->hrtick_timer
);
1074 * High-resolution timer tick.
1075 * Runs from hardirq context with interrupts disabled.
1077 static enum hrtimer_restart
hrtick(struct hrtimer
*timer
)
1079 struct rq
*rq
= container_of(timer
, struct rq
, hrtick_timer
);
1081 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
1083 spin_lock(&rq
->lock
);
1084 update_rq_clock(rq
);
1085 rq
->curr
->sched_class
->task_tick(rq
, rq
->curr
, 1);
1086 spin_unlock(&rq
->lock
);
1088 return HRTIMER_NORESTART
;
1093 * called from hardirq (IPI) context
1095 static void __hrtick_start(void *arg
)
1097 struct rq
*rq
= arg
;
1099 spin_lock(&rq
->lock
);
1100 hrtimer_restart(&rq
->hrtick_timer
);
1101 rq
->hrtick_csd_pending
= 0;
1102 spin_unlock(&rq
->lock
);
1106 * Called to set the hrtick timer state.
1108 * called with rq->lock held and irqs disabled
1110 static void hrtick_start(struct rq
*rq
, u64 delay
)
1112 struct hrtimer
*timer
= &rq
->hrtick_timer
;
1113 ktime_t time
= ktime_add_ns(timer
->base
->get_time(), delay
);
1115 hrtimer_set_expires(timer
, time
);
1117 if (rq
== this_rq()) {
1118 hrtimer_restart(timer
);
1119 } else if (!rq
->hrtick_csd_pending
) {
1120 __smp_call_function_single(cpu_of(rq
), &rq
->hrtick_csd
, 0);
1121 rq
->hrtick_csd_pending
= 1;
1126 hotplug_hrtick(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
1128 int cpu
= (int)(long)hcpu
;
1131 case CPU_UP_CANCELED
:
1132 case CPU_UP_CANCELED_FROZEN
:
1133 case CPU_DOWN_PREPARE
:
1134 case CPU_DOWN_PREPARE_FROZEN
:
1136 case CPU_DEAD_FROZEN
:
1137 hrtick_clear(cpu_rq(cpu
));
1144 static __init
void init_hrtick(void)
1146 hotcpu_notifier(hotplug_hrtick
, 0);
1150 * Called to set the hrtick timer state.
1152 * called with rq->lock held and irqs disabled
1154 static void hrtick_start(struct rq
*rq
, u64 delay
)
1156 __hrtimer_start_range_ns(&rq
->hrtick_timer
, ns_to_ktime(delay
), 0,
1157 HRTIMER_MODE_REL_PINNED
, 0);
1160 static inline void init_hrtick(void)
1163 #endif /* CONFIG_SMP */
1165 static void init_rq_hrtick(struct rq
*rq
)
1168 rq
->hrtick_csd_pending
= 0;
1170 rq
->hrtick_csd
.flags
= 0;
1171 rq
->hrtick_csd
.func
= __hrtick_start
;
1172 rq
->hrtick_csd
.info
= rq
;
1175 hrtimer_init(&rq
->hrtick_timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
1176 rq
->hrtick_timer
.function
= hrtick
;
1178 #else /* CONFIG_SCHED_HRTICK */
1179 static inline void hrtick_clear(struct rq
*rq
)
1183 static inline void init_rq_hrtick(struct rq
*rq
)
1187 static inline void init_hrtick(void)
1190 #endif /* CONFIG_SCHED_HRTICK */
1193 * resched_task - mark a task 'to be rescheduled now'.
1195 * On UP this means the setting of the need_resched flag, on SMP it
1196 * might also involve a cross-CPU call to trigger the scheduler on
1201 #ifndef tsk_is_polling
1202 #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
1205 static void resched_task(struct task_struct
*p
)
1209 assert_spin_locked(&task_rq(p
)->lock
);
1211 if (test_tsk_need_resched(p
))
1214 set_tsk_need_resched(p
);
1217 if (cpu
== smp_processor_id())
1220 /* NEED_RESCHED must be visible before we test polling */
1222 if (!tsk_is_polling(p
))
1223 smp_send_reschedule(cpu
);
1226 static void resched_cpu(int cpu
)
1228 struct rq
*rq
= cpu_rq(cpu
);
1229 unsigned long flags
;
1231 if (!spin_trylock_irqsave(&rq
->lock
, flags
))
1233 resched_task(cpu_curr(cpu
));
1234 spin_unlock_irqrestore(&rq
->lock
, flags
);
1239 * When add_timer_on() enqueues a timer into the timer wheel of an
1240 * idle CPU then this timer might expire before the next timer event
1241 * which is scheduled to wake up that CPU. In case of a completely
1242 * idle system the next event might even be infinite time into the
1243 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
1244 * leaves the inner idle loop so the newly added timer is taken into
1245 * account when the CPU goes back to idle and evaluates the timer
1246 * wheel for the next timer event.
1248 void wake_up_idle_cpu(int cpu
)
1250 struct rq
*rq
= cpu_rq(cpu
);
1252 if (cpu
== smp_processor_id())
1256 * This is safe, as this function is called with the timer
1257 * wheel base lock of (cpu) held. When the CPU is on the way
1258 * to idle and has not yet set rq->curr to idle then it will
1259 * be serialized on the timer wheel base lock and take the new
1260 * timer into account automatically.
1262 if (rq
->curr
!= rq
->idle
)
1266 * We can set TIF_RESCHED on the idle task of the other CPU
1267 * lockless. The worst case is that the other CPU runs the
1268 * idle task through an additional NOOP schedule()
1270 set_tsk_need_resched(rq
->idle
);
1272 /* NEED_RESCHED must be visible before we test polling */
1274 if (!tsk_is_polling(rq
->idle
))
1275 smp_send_reschedule(cpu
);
1277 #endif /* CONFIG_NO_HZ */
1279 #else /* !CONFIG_SMP */
1280 static void resched_task(struct task_struct
*p
)
1282 assert_spin_locked(&task_rq(p
)->lock
);
1283 set_tsk_need_resched(p
);
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 static unsigned long source_load(int cpu
, int type
);
1496 static unsigned long target_load(int cpu
, int type
);
1497 static int task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
);
1499 static unsigned long cpu_avg_load_per_task(int cpu
)
1501 struct rq
*rq
= cpu_rq(cpu
);
1502 unsigned long nr_running
= ACCESS_ONCE(rq
->nr_running
);
1505 rq
->avg_load_per_task
= rq
->load
.weight
/ nr_running
;
1507 rq
->avg_load_per_task
= 0;
1509 return rq
->avg_load_per_task
;
1512 #ifdef CONFIG_FAIR_GROUP_SCHED
1514 static void __set_se_shares(struct sched_entity
*se
, unsigned long shares
);
1517 * Calculate and set the cpu's group shares.
1520 update_group_shares_cpu(struct task_group
*tg
, int cpu
,
1521 unsigned long sd_shares
, unsigned long sd_rq_weight
)
1523 unsigned long shares
;
1524 unsigned long rq_weight
;
1529 rq_weight
= tg
->cfs_rq
[cpu
]->rq_weight
;
1532 * \Sum shares * rq_weight
1533 * shares = -----------------------
1537 shares
= (sd_shares
* rq_weight
) / sd_rq_weight
;
1538 shares
= clamp_t(unsigned long, shares
, MIN_SHARES
, MAX_SHARES
);
1540 if (abs(shares
- tg
->se
[cpu
]->load
.weight
) >
1541 sysctl_sched_shares_thresh
) {
1542 struct rq
*rq
= cpu_rq(cpu
);
1543 unsigned long flags
;
1545 spin_lock_irqsave(&rq
->lock
, flags
);
1546 tg
->cfs_rq
[cpu
]->shares
= shares
;
1548 __set_se_shares(tg
->se
[cpu
], shares
);
1549 spin_unlock_irqrestore(&rq
->lock
, flags
);
1554 * Re-compute the task group their per cpu shares over the given domain.
1555 * This needs to be done in a bottom-up fashion because the rq weight of a
1556 * parent group depends on the shares of its child groups.
1558 static int tg_shares_up(struct task_group
*tg
, void *data
)
1560 unsigned long weight
, rq_weight
= 0;
1561 unsigned long shares
= 0;
1562 struct sched_domain
*sd
= data
;
1565 for_each_cpu(i
, sched_domain_span(sd
)) {
1567 * If there are currently no tasks on the cpu pretend there
1568 * is one of average load so that when a new task gets to
1569 * run here it will not get delayed by group starvation.
1571 weight
= tg
->cfs_rq
[i
]->load
.weight
;
1573 weight
= NICE_0_LOAD
;
1575 tg
->cfs_rq
[i
]->rq_weight
= weight
;
1576 rq_weight
+= weight
;
1577 shares
+= tg
->cfs_rq
[i
]->shares
;
1580 if ((!shares
&& rq_weight
) || shares
> tg
->shares
)
1581 shares
= tg
->shares
;
1583 if (!sd
->parent
|| !(sd
->parent
->flags
& SD_LOAD_BALANCE
))
1584 shares
= tg
->shares
;
1586 for_each_cpu(i
, sched_domain_span(sd
))
1587 update_group_shares_cpu(tg
, i
, shares
, rq_weight
);
1593 * Compute the cpu's hierarchical load factor for each task group.
1594 * This needs to be done in a top-down fashion because the load of a child
1595 * group is a fraction of its parents load.
1597 static int tg_load_down(struct task_group
*tg
, void *data
)
1600 long cpu
= (long)data
;
1603 load
= cpu_rq(cpu
)->load
.weight
;
1605 load
= tg
->parent
->cfs_rq
[cpu
]->h_load
;
1606 load
*= tg
->cfs_rq
[cpu
]->shares
;
1607 load
/= tg
->parent
->cfs_rq
[cpu
]->load
.weight
+ 1;
1610 tg
->cfs_rq
[cpu
]->h_load
= load
;
1615 static void update_shares(struct sched_domain
*sd
)
1617 u64 now
= cpu_clock(raw_smp_processor_id());
1618 s64 elapsed
= now
- sd
->last_update
;
1620 if (elapsed
>= (s64
)(u64
)sysctl_sched_shares_ratelimit
) {
1621 sd
->last_update
= now
;
1622 walk_tg_tree(tg_nop
, tg_shares_up
, sd
);
1626 static void update_shares_locked(struct rq
*rq
, struct sched_domain
*sd
)
1628 spin_unlock(&rq
->lock
);
1630 spin_lock(&rq
->lock
);
1633 static void update_h_load(long cpu
)
1635 walk_tg_tree(tg_load_down
, tg_nop
, (void *)cpu
);
1640 static inline void update_shares(struct sched_domain
*sd
)
1644 static inline void update_shares_locked(struct rq
*rq
, struct sched_domain
*sd
)
1650 #ifdef CONFIG_PREEMPT
1653 * fair double_lock_balance: Safely acquires both rq->locks in a fair
1654 * way at the expense of forcing extra atomic operations in all
1655 * invocations. This assures that the double_lock is acquired using the
1656 * same underlying policy as the spinlock_t on this architecture, which
1657 * reduces latency compared to the unfair variant below. However, it
1658 * also adds more overhead and therefore may reduce throughput.
1660 static inline int _double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1661 __releases(this_rq
->lock
)
1662 __acquires(busiest
->lock
)
1663 __acquires(this_rq
->lock
)
1665 spin_unlock(&this_rq
->lock
);
1666 double_rq_lock(this_rq
, busiest
);
1673 * Unfair double_lock_balance: Optimizes throughput at the expense of
1674 * latency by eliminating extra atomic operations when the locks are
1675 * already in proper order on entry. This favors lower cpu-ids and will
1676 * grant the double lock to lower cpus over higher ids under contention,
1677 * regardless of entry order into the function.
1679 static int _double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1680 __releases(this_rq
->lock
)
1681 __acquires(busiest
->lock
)
1682 __acquires(this_rq
->lock
)
1686 if (unlikely(!spin_trylock(&busiest
->lock
))) {
1687 if (busiest
< this_rq
) {
1688 spin_unlock(&this_rq
->lock
);
1689 spin_lock(&busiest
->lock
);
1690 spin_lock_nested(&this_rq
->lock
, SINGLE_DEPTH_NESTING
);
1693 spin_lock_nested(&busiest
->lock
, SINGLE_DEPTH_NESTING
);
1698 #endif /* CONFIG_PREEMPT */
1701 * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
1703 static int double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1705 if (unlikely(!irqs_disabled())) {
1706 /* printk() doesn't work good under rq->lock */
1707 spin_unlock(&this_rq
->lock
);
1711 return _double_lock_balance(this_rq
, busiest
);
1714 static inline void double_unlock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1715 __releases(busiest
->lock
)
1717 spin_unlock(&busiest
->lock
);
1718 lock_set_subclass(&this_rq
->lock
.dep_map
, 0, _RET_IP_
);
1722 #ifdef CONFIG_FAIR_GROUP_SCHED
1723 static void cfs_rq_set_shares(struct cfs_rq
*cfs_rq
, unsigned long shares
)
1726 cfs_rq
->shares
= shares
;
1731 #include "sched_stats.h"
1732 #include "sched_idletask.c"
1733 #include "sched_fair.c"
1734 #include "sched_rt.c"
1735 #ifdef CONFIG_SCHED_DEBUG
1736 # include "sched_debug.c"
1739 #define sched_class_highest (&rt_sched_class)
1740 #define for_each_class(class) \
1741 for (class = sched_class_highest; class; class = class->next)
1743 static void inc_nr_running(struct rq
*rq
)
1748 static void dec_nr_running(struct rq
*rq
)
1753 static void set_load_weight(struct task_struct
*p
)
1755 if (task_has_rt_policy(p
)) {
1756 p
->se
.load
.weight
= prio_to_weight
[0] * 2;
1757 p
->se
.load
.inv_weight
= prio_to_wmult
[0] >> 1;
1762 * SCHED_IDLE tasks get minimal weight:
1764 if (p
->policy
== SCHED_IDLE
) {
1765 p
->se
.load
.weight
= WEIGHT_IDLEPRIO
;
1766 p
->se
.load
.inv_weight
= WMULT_IDLEPRIO
;
1770 p
->se
.load
.weight
= prio_to_weight
[p
->static_prio
- MAX_RT_PRIO
];
1771 p
->se
.load
.inv_weight
= prio_to_wmult
[p
->static_prio
- MAX_RT_PRIO
];
1774 static void update_avg(u64
*avg
, u64 sample
)
1776 s64 diff
= sample
- *avg
;
1780 static void enqueue_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
)
1783 p
->se
.start_runtime
= p
->se
.sum_exec_runtime
;
1785 sched_info_queued(p
);
1786 p
->sched_class
->enqueue_task(rq
, p
, wakeup
);
1790 static void dequeue_task(struct rq
*rq
, struct task_struct
*p
, int sleep
)
1793 if (p
->se
.last_wakeup
) {
1794 update_avg(&p
->se
.avg_overlap
,
1795 p
->se
.sum_exec_runtime
- p
->se
.last_wakeup
);
1796 p
->se
.last_wakeup
= 0;
1798 update_avg(&p
->se
.avg_wakeup
,
1799 sysctl_sched_wakeup_granularity
);
1803 sched_info_dequeued(p
);
1804 p
->sched_class
->dequeue_task(rq
, p
, sleep
);
1809 * __normal_prio - return the priority that is based on the static prio
1811 static inline int __normal_prio(struct task_struct
*p
)
1813 return p
->static_prio
;
1817 * Calculate the expected normal priority: i.e. priority
1818 * without taking RT-inheritance into account. Might be
1819 * boosted by interactivity modifiers. Changes upon fork,
1820 * setprio syscalls, and whenever the interactivity
1821 * estimator recalculates.
1823 static inline int normal_prio(struct task_struct
*p
)
1827 if (task_has_rt_policy(p
))
1828 prio
= MAX_RT_PRIO
-1 - p
->rt_priority
;
1830 prio
= __normal_prio(p
);
1835 * Calculate the current priority, i.e. the priority
1836 * taken into account by the scheduler. This value might
1837 * be boosted by RT tasks, or might be boosted by
1838 * interactivity modifiers. Will be RT if the task got
1839 * RT-boosted. If not then it returns p->normal_prio.
1841 static int effective_prio(struct task_struct
*p
)
1843 p
->normal_prio
= normal_prio(p
);
1845 * If we are RT tasks or we were boosted to RT priority,
1846 * keep the priority unchanged. Otherwise, update priority
1847 * to the normal priority:
1849 if (!rt_prio(p
->prio
))
1850 return p
->normal_prio
;
1855 * activate_task - move a task to the runqueue.
1857 static void activate_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
)
1859 if (task_contributes_to_load(p
))
1860 rq
->nr_uninterruptible
--;
1862 enqueue_task(rq
, p
, wakeup
);
1867 * deactivate_task - remove a task from the runqueue.
1869 static void deactivate_task(struct rq
*rq
, struct task_struct
*p
, int sleep
)
1871 if (task_contributes_to_load(p
))
1872 rq
->nr_uninterruptible
++;
1874 dequeue_task(rq
, p
, sleep
);
1879 * task_curr - is this task currently executing on a CPU?
1880 * @p: the task in question.
1882 inline int task_curr(const struct task_struct
*p
)
1884 return cpu_curr(task_cpu(p
)) == p
;
1887 static inline void __set_task_cpu(struct task_struct
*p
, unsigned int cpu
)
1889 set_task_rq(p
, cpu
);
1892 * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be
1893 * successfuly executed on another CPU. We must ensure that updates of
1894 * per-task data have been completed by this moment.
1897 task_thread_info(p
)->cpu
= cpu
;
1901 static inline void check_class_changed(struct rq
*rq
, struct task_struct
*p
,
1902 const struct sched_class
*prev_class
,
1903 int oldprio
, int running
)
1905 if (prev_class
!= p
->sched_class
) {
1906 if (prev_class
->switched_from
)
1907 prev_class
->switched_from(rq
, p
, running
);
1908 p
->sched_class
->switched_to(rq
, p
, running
);
1910 p
->sched_class
->prio_changed(rq
, p
, oldprio
, running
);
1915 /* Used instead of source_load when we know the type == 0 */
1916 static unsigned long weighted_cpuload(const int cpu
)
1918 return cpu_rq(cpu
)->load
.weight
;
1922 * Is this task likely cache-hot:
1925 task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
)
1930 * Buddy candidates are cache hot:
1932 if (sched_feat(CACHE_HOT_BUDDY
) &&
1933 (&p
->se
== cfs_rq_of(&p
->se
)->next
||
1934 &p
->se
== cfs_rq_of(&p
->se
)->last
))
1937 if (p
->sched_class
!= &fair_sched_class
)
1940 if (sysctl_sched_migration_cost
== -1)
1942 if (sysctl_sched_migration_cost
== 0)
1945 delta
= now
- p
->se
.exec_start
;
1947 return delta
< (s64
)sysctl_sched_migration_cost
;
1951 void set_task_cpu(struct task_struct
*p
, unsigned int new_cpu
)
1953 int old_cpu
= task_cpu(p
);
1954 struct rq
*old_rq
= cpu_rq(old_cpu
), *new_rq
= cpu_rq(new_cpu
);
1955 struct cfs_rq
*old_cfsrq
= task_cfs_rq(p
),
1956 *new_cfsrq
= cpu_cfs_rq(old_cfsrq
, new_cpu
);
1959 clock_offset
= old_rq
->clock
- new_rq
->clock
;
1961 trace_sched_migrate_task(p
, task_cpu(p
), new_cpu
);
1963 #ifdef CONFIG_SCHEDSTATS
1964 if (p
->se
.wait_start
)
1965 p
->se
.wait_start
-= clock_offset
;
1966 if (p
->se
.sleep_start
)
1967 p
->se
.sleep_start
-= clock_offset
;
1968 if (p
->se
.block_start
)
1969 p
->se
.block_start
-= clock_offset
;
1970 if (old_cpu
!= new_cpu
) {
1971 schedstat_inc(p
, se
.nr_migrations
);
1972 if (task_hot(p
, old_rq
->clock
, NULL
))
1973 schedstat_inc(p
, se
.nr_forced2_migrations
);
1976 p
->se
.vruntime
-= old_cfsrq
->min_vruntime
-
1977 new_cfsrq
->min_vruntime
;
1979 __set_task_cpu(p
, new_cpu
);
1982 struct migration_req
{
1983 struct list_head list
;
1985 struct task_struct
*task
;
1988 struct completion done
;
1992 * The task's runqueue lock must be held.
1993 * Returns true if you have to wait for migration thread.
1996 migrate_task(struct task_struct
*p
, int dest_cpu
, struct migration_req
*req
)
1998 struct rq
*rq
= task_rq(p
);
2001 * If the task is not on a runqueue (and not running), then
2002 * it is sufficient to simply update the task's cpu field.
2004 if (!p
->se
.on_rq
&& !task_running(rq
, p
)) {
2005 set_task_cpu(p
, dest_cpu
);
2009 init_completion(&req
->done
);
2011 req
->dest_cpu
= dest_cpu
;
2012 list_add(&req
->list
, &rq
->migration_queue
);
2018 * wait_task_inactive - wait for a thread to unschedule.
2020 * If @match_state is nonzero, it's the @p->state value just checked and
2021 * not expected to change. If it changes, i.e. @p might have woken up,
2022 * then return zero. When we succeed in waiting for @p to be off its CPU,
2023 * we return a positive number (its total switch count). If a second call
2024 * a short while later returns the same number, the caller can be sure that
2025 * @p has remained unscheduled the whole time.
2027 * The caller must ensure that the task *will* unschedule sometime soon,
2028 * else this function might spin for a *long* time. This function can't
2029 * be called with interrupts off, or it may introduce deadlock with
2030 * smp_call_function() if an IPI is sent by the same process we are
2031 * waiting to become inactive.
2033 unsigned long wait_task_inactive(struct task_struct
*p
, long match_state
)
2035 unsigned long flags
;
2042 * We do the initial early heuristics without holding
2043 * any task-queue locks at all. We'll only try to get
2044 * the runqueue lock when things look like they will
2050 * If the task is actively running on another CPU
2051 * still, just relax and busy-wait without holding
2054 * NOTE! Since we don't hold any locks, it's not
2055 * even sure that "rq" stays as the right runqueue!
2056 * But we don't care, since "task_running()" will
2057 * return false if the runqueue has changed and p
2058 * is actually now running somewhere else!
2060 while (task_running(rq
, p
)) {
2061 if (match_state
&& unlikely(p
->state
!= match_state
))
2067 * Ok, time to look more closely! We need the rq
2068 * lock now, to be *sure*. If we're wrong, we'll
2069 * just go back and repeat.
2071 rq
= task_rq_lock(p
, &flags
);
2072 trace_sched_wait_task(rq
, p
);
2073 running
= task_running(rq
, p
);
2074 on_rq
= p
->se
.on_rq
;
2076 if (!match_state
|| p
->state
== match_state
)
2077 ncsw
= p
->nvcsw
| LONG_MIN
; /* sets MSB */
2078 task_rq_unlock(rq
, &flags
);
2081 * If it changed from the expected state, bail out now.
2083 if (unlikely(!ncsw
))
2087 * Was it really running after all now that we
2088 * checked with the proper locks actually held?
2090 * Oops. Go back and try again..
2092 if (unlikely(running
)) {
2098 * It's not enough that it's not actively running,
2099 * it must be off the runqueue _entirely_, and not
2102 * So if it was still runnable (but just not actively
2103 * running right now), it's preempted, and we should
2104 * yield - it could be a while.
2106 if (unlikely(on_rq
)) {
2107 schedule_timeout_uninterruptible(1);
2112 * Ahh, all good. It wasn't running, and it wasn't
2113 * runnable, which means that it will never become
2114 * running in the future either. We're all done!
2123 * kick_process - kick a running thread to enter/exit the kernel
2124 * @p: the to-be-kicked thread
2126 * Cause a process which is running on another CPU to enter
2127 * kernel-mode, without any delay. (to get signals handled.)
2129 * NOTE: this function doesnt have to take the runqueue lock,
2130 * because all it wants to ensure is that the remote task enters
2131 * the kernel. If the IPI races and the task has been migrated
2132 * to another CPU then no harm is done and the purpose has been
2135 void kick_process(struct task_struct
*p
)
2141 if ((cpu
!= smp_processor_id()) && task_curr(p
))
2142 smp_send_reschedule(cpu
);
2147 * Return a low guess at the load of a migration-source cpu weighted
2148 * according to the scheduling class and "nice" value.
2150 * We want to under-estimate the load of migration sources, to
2151 * balance conservatively.
2153 static unsigned long source_load(int cpu
, int type
)
2155 struct rq
*rq
= cpu_rq(cpu
);
2156 unsigned long total
= weighted_cpuload(cpu
);
2158 if (type
== 0 || !sched_feat(LB_BIAS
))
2161 return min(rq
->cpu_load
[type
-1], total
);
2165 * Return a high guess at the load of a migration-target cpu weighted
2166 * according to the scheduling class and "nice" value.
2168 static unsigned long target_load(int cpu
, int type
)
2170 struct rq
*rq
= cpu_rq(cpu
);
2171 unsigned long total
= weighted_cpuload(cpu
);
2173 if (type
== 0 || !sched_feat(LB_BIAS
))
2176 return max(rq
->cpu_load
[type
-1], total
);
2180 * find_idlest_group finds and returns the least busy CPU group within the
2183 static struct sched_group
*
2184 find_idlest_group(struct sched_domain
*sd
, struct task_struct
*p
, int this_cpu
)
2186 struct sched_group
*idlest
= NULL
, *this = NULL
, *group
= sd
->groups
;
2187 unsigned long min_load
= ULONG_MAX
, this_load
= 0;
2188 int load_idx
= sd
->forkexec_idx
;
2189 int imbalance
= 100 + (sd
->imbalance_pct
-100)/2;
2192 unsigned long load
, avg_load
;
2196 /* Skip over this group if it has no CPUs allowed */
2197 if (!cpumask_intersects(sched_group_cpus(group
),
2201 local_group
= cpumask_test_cpu(this_cpu
,
2202 sched_group_cpus(group
));
2204 /* Tally up the load of all CPUs in the group */
2207 for_each_cpu(i
, sched_group_cpus(group
)) {
2208 /* Bias balancing toward cpus of our domain */
2210 load
= source_load(i
, load_idx
);
2212 load
= target_load(i
, load_idx
);
2217 /* Adjust by relative CPU power of the group */
2218 avg_load
= sg_div_cpu_power(group
,
2219 avg_load
* SCHED_LOAD_SCALE
);
2222 this_load
= avg_load
;
2224 } else if (avg_load
< min_load
) {
2225 min_load
= avg_load
;
2228 } while (group
= group
->next
, group
!= sd
->groups
);
2230 if (!idlest
|| 100*this_load
< imbalance
*min_load
)
2236 * find_idlest_cpu - find the idlest cpu among the cpus in group.
2239 find_idlest_cpu(struct sched_group
*group
, struct task_struct
*p
, int this_cpu
)
2241 unsigned long load
, min_load
= ULONG_MAX
;
2245 /* Traverse only the allowed CPUs */
2246 for_each_cpu_and(i
, sched_group_cpus(group
), &p
->cpus_allowed
) {
2247 load
= weighted_cpuload(i
);
2249 if (load
< min_load
|| (load
== min_load
&& i
== this_cpu
)) {
2259 * sched_balance_self: balance the current task (running on cpu) in domains
2260 * that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and
2263 * Balance, ie. select the least loaded group.
2265 * Returns the target CPU number, or the same CPU if no balancing is needed.
2267 * preempt must be disabled.
2269 static int sched_balance_self(int cpu
, int flag
)
2271 struct task_struct
*t
= current
;
2272 struct sched_domain
*tmp
, *sd
= NULL
;
2274 for_each_domain(cpu
, tmp
) {
2276 * If power savings logic is enabled for a domain, stop there.
2278 if (tmp
->flags
& SD_POWERSAVINGS_BALANCE
)
2280 if (tmp
->flags
& flag
)
2288 struct sched_group
*group
;
2289 int new_cpu
, weight
;
2291 if (!(sd
->flags
& flag
)) {
2296 group
= find_idlest_group(sd
, t
, cpu
);
2302 new_cpu
= find_idlest_cpu(group
, t
, cpu
);
2303 if (new_cpu
== -1 || new_cpu
== cpu
) {
2304 /* Now try balancing at a lower domain level of cpu */
2309 /* Now try balancing at a lower domain level of new_cpu */
2311 weight
= cpumask_weight(sched_domain_span(sd
));
2313 for_each_domain(cpu
, tmp
) {
2314 if (weight
<= cpumask_weight(sched_domain_span(tmp
)))
2316 if (tmp
->flags
& flag
)
2319 /* while loop will break here if sd == NULL */
2325 #endif /* CONFIG_SMP */
2328 * try_to_wake_up - wake up a thread
2329 * @p: the to-be-woken-up thread
2330 * @state: the mask of task states that can be woken
2331 * @sync: do a synchronous wakeup?
2333 * Put it on the run-queue if it's not already there. The "current"
2334 * thread is always on the run-queue (except when the actual
2335 * re-schedule is in progress), and as such you're allowed to do
2336 * the simpler "current->state = TASK_RUNNING" to mark yourself
2337 * runnable without the overhead of this.
2339 * returns failure only if the task is already active.
2341 static int try_to_wake_up(struct task_struct
*p
, unsigned int state
, int sync
)
2343 int cpu
, orig_cpu
, this_cpu
, success
= 0;
2344 unsigned long flags
;
2348 if (!sched_feat(SYNC_WAKEUPS
))
2352 if (sched_feat(LB_WAKEUP_UPDATE
) && !root_task_group_empty()) {
2353 struct sched_domain
*sd
;
2355 this_cpu
= raw_smp_processor_id();
2358 for_each_domain(this_cpu
, sd
) {
2359 if (cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
2368 rq
= task_rq_lock(p
, &flags
);
2369 update_rq_clock(rq
);
2370 old_state
= p
->state
;
2371 if (!(old_state
& state
))
2379 this_cpu
= smp_processor_id();
2382 if (unlikely(task_running(rq
, p
)))
2385 cpu
= p
->sched_class
->select_task_rq(p
, sync
);
2386 if (cpu
!= orig_cpu
) {
2387 set_task_cpu(p
, cpu
);
2388 task_rq_unlock(rq
, &flags
);
2389 /* might preempt at this point */
2390 rq
= task_rq_lock(p
, &flags
);
2391 old_state
= p
->state
;
2392 if (!(old_state
& state
))
2397 this_cpu
= smp_processor_id();
2401 #ifdef CONFIG_SCHEDSTATS
2402 schedstat_inc(rq
, ttwu_count
);
2403 if (cpu
== this_cpu
)
2404 schedstat_inc(rq
, ttwu_local
);
2406 struct sched_domain
*sd
;
2407 for_each_domain(this_cpu
, sd
) {
2408 if (cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
2409 schedstat_inc(sd
, ttwu_wake_remote
);
2414 #endif /* CONFIG_SCHEDSTATS */
2417 #endif /* CONFIG_SMP */
2418 schedstat_inc(p
, se
.nr_wakeups
);
2420 schedstat_inc(p
, se
.nr_wakeups_sync
);
2421 if (orig_cpu
!= cpu
)
2422 schedstat_inc(p
, se
.nr_wakeups_migrate
);
2423 if (cpu
== this_cpu
)
2424 schedstat_inc(p
, se
.nr_wakeups_local
);
2426 schedstat_inc(p
, se
.nr_wakeups_remote
);
2427 activate_task(rq
, p
, 1);
2431 * Only attribute actual wakeups done by this task.
2433 if (!in_interrupt()) {
2434 struct sched_entity
*se
= ¤t
->se
;
2435 u64 sample
= se
->sum_exec_runtime
;
2437 if (se
->last_wakeup
)
2438 sample
-= se
->last_wakeup
;
2440 sample
-= se
->start_runtime
;
2441 update_avg(&se
->avg_wakeup
, sample
);
2443 se
->last_wakeup
= se
->sum_exec_runtime
;
2447 trace_sched_wakeup(rq
, p
, success
);
2448 check_preempt_curr(rq
, p
, sync
);
2450 p
->state
= TASK_RUNNING
;
2452 if (p
->sched_class
->task_wake_up
)
2453 p
->sched_class
->task_wake_up(rq
, p
);
2456 task_rq_unlock(rq
, &flags
);
2461 int wake_up_process(struct task_struct
*p
)
2463 return try_to_wake_up(p
, TASK_ALL
, 0);
2465 EXPORT_SYMBOL(wake_up_process
);
2467 int wake_up_state(struct task_struct
*p
, unsigned int state
)
2469 return try_to_wake_up(p
, state
, 0);
2473 * Perform scheduler related setup for a newly forked process p.
2474 * p is forked by current.
2476 * __sched_fork() is basic setup used by init_idle() too:
2478 static void __sched_fork(struct task_struct
*p
)
2480 p
->se
.exec_start
= 0;
2481 p
->se
.sum_exec_runtime
= 0;
2482 p
->se
.prev_sum_exec_runtime
= 0;
2483 p
->se
.last_wakeup
= 0;
2484 p
->se
.avg_overlap
= 0;
2485 p
->se
.start_runtime
= 0;
2486 p
->se
.avg_wakeup
= sysctl_sched_wakeup_granularity
;
2488 #ifdef CONFIG_SCHEDSTATS
2489 p
->se
.wait_start
= 0;
2490 p
->se
.sum_sleep_runtime
= 0;
2491 p
->se
.sleep_start
= 0;
2492 p
->se
.block_start
= 0;
2493 p
->se
.sleep_max
= 0;
2494 p
->se
.block_max
= 0;
2496 p
->se
.slice_max
= 0;
2500 INIT_LIST_HEAD(&p
->rt
.run_list
);
2502 INIT_LIST_HEAD(&p
->se
.group_node
);
2504 #ifdef CONFIG_PREEMPT_NOTIFIERS
2505 INIT_HLIST_HEAD(&p
->preempt_notifiers
);
2509 * We mark the process as running here, but have not actually
2510 * inserted it onto the runqueue yet. This guarantees that
2511 * nobody will actually run it, and a signal or other external
2512 * event cannot wake it up and insert it on the runqueue either.
2514 p
->state
= TASK_RUNNING
;
2518 * fork()/clone()-time setup:
2520 void sched_fork(struct task_struct
*p
, int clone_flags
)
2522 int cpu
= get_cpu();
2527 cpu
= sched_balance_self(cpu
, SD_BALANCE_FORK
);
2529 set_task_cpu(p
, cpu
);
2532 * Make sure we do not leak PI boosting priority to the child:
2534 p
->prio
= current
->normal_prio
;
2535 if (!rt_prio(p
->prio
))
2536 p
->sched_class
= &fair_sched_class
;
2538 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
2539 if (likely(sched_info_on()))
2540 memset(&p
->sched_info
, 0, sizeof(p
->sched_info
));
2542 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
2545 #ifdef CONFIG_PREEMPT
2546 /* Want to start with kernel preemption disabled. */
2547 task_thread_info(p
)->preempt_count
= 1;
2549 plist_node_init(&p
->pushable_tasks
, MAX_PRIO
);
2555 * wake_up_new_task - wake up a newly created task for the first time.
2557 * This function will do some initial scheduler statistics housekeeping
2558 * that must be done for every newly created context, then puts the task
2559 * on the runqueue and wakes it.
2561 void wake_up_new_task(struct task_struct
*p
, unsigned long clone_flags
)
2563 unsigned long flags
;
2566 rq
= task_rq_lock(p
, &flags
);
2567 BUG_ON(p
->state
!= TASK_RUNNING
);
2568 update_rq_clock(rq
);
2570 p
->prio
= effective_prio(p
);
2572 if (!p
->sched_class
->task_new
|| !current
->se
.on_rq
) {
2573 activate_task(rq
, p
, 0);
2576 * Let the scheduling class do new task startup
2577 * management (if any):
2579 p
->sched_class
->task_new(rq
, p
);
2582 trace_sched_wakeup_new(rq
, p
, 1);
2583 check_preempt_curr(rq
, p
, 0);
2585 if (p
->sched_class
->task_wake_up
)
2586 p
->sched_class
->task_wake_up(rq
, p
);
2588 task_rq_unlock(rq
, &flags
);
2591 #ifdef CONFIG_PREEMPT_NOTIFIERS
2594 * preempt_notifier_register - tell me when current is being preempted & rescheduled
2595 * @notifier: notifier struct to register
2597 void preempt_notifier_register(struct preempt_notifier
*notifier
)
2599 hlist_add_head(¬ifier
->link
, ¤t
->preempt_notifiers
);
2601 EXPORT_SYMBOL_GPL(preempt_notifier_register
);
2604 * preempt_notifier_unregister - no longer interested in preemption notifications
2605 * @notifier: notifier struct to unregister
2607 * This is safe to call from within a preemption notifier.
2609 void preempt_notifier_unregister(struct preempt_notifier
*notifier
)
2611 hlist_del(¬ifier
->link
);
2613 EXPORT_SYMBOL_GPL(preempt_notifier_unregister
);
2615 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2617 struct preempt_notifier
*notifier
;
2618 struct hlist_node
*node
;
2620 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
2621 notifier
->ops
->sched_in(notifier
, raw_smp_processor_id());
2625 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2626 struct task_struct
*next
)
2628 struct preempt_notifier
*notifier
;
2629 struct hlist_node
*node
;
2631 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
2632 notifier
->ops
->sched_out(notifier
, next
);
2635 #else /* !CONFIG_PREEMPT_NOTIFIERS */
2637 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2642 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2643 struct task_struct
*next
)
2647 #endif /* CONFIG_PREEMPT_NOTIFIERS */
2650 * prepare_task_switch - prepare to switch tasks
2651 * @rq: the runqueue preparing to switch
2652 * @prev: the current task that is being switched out
2653 * @next: the task we are going to switch to.
2655 * This is called with the rq lock held and interrupts off. It must
2656 * be paired with a subsequent finish_task_switch after the context
2659 * prepare_task_switch sets up locking and calls architecture specific
2663 prepare_task_switch(struct rq
*rq
, struct task_struct
*prev
,
2664 struct task_struct
*next
)
2666 fire_sched_out_preempt_notifiers(prev
, next
);
2667 prepare_lock_switch(rq
, next
);
2668 prepare_arch_switch(next
);
2672 * finish_task_switch - clean up after a task-switch
2673 * @rq: runqueue associated with task-switch
2674 * @prev: the thread we just switched away from.
2676 * finish_task_switch must be called after the context switch, paired
2677 * with a prepare_task_switch call before the context switch.
2678 * finish_task_switch will reconcile locking set up by prepare_task_switch,
2679 * and do any other architecture-specific cleanup actions.
2681 * Note that we may have delayed dropping an mm in context_switch(). If
2682 * so, we finish that here outside of the runqueue lock. (Doing it
2683 * with the lock held can cause deadlocks; see schedule() for
2686 static void finish_task_switch(struct rq
*rq
, struct task_struct
*prev
)
2687 __releases(rq
->lock
)
2689 struct mm_struct
*mm
= rq
->prev_mm
;
2692 int post_schedule
= 0;
2694 if (current
->sched_class
->needs_post_schedule
)
2695 post_schedule
= current
->sched_class
->needs_post_schedule(rq
);
2701 * A task struct has one reference for the use as "current".
2702 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
2703 * schedule one last time. The schedule call will never return, and
2704 * the scheduled task must drop that reference.
2705 * The test for TASK_DEAD must occur while the runqueue locks are
2706 * still held, otherwise prev could be scheduled on another cpu, die
2707 * there before we look at prev->state, and then the reference would
2709 * Manfred Spraul <manfred@colorfullife.com>
2711 prev_state
= prev
->state
;
2712 finish_arch_switch(prev
);
2713 finish_lock_switch(rq
, prev
);
2716 current
->sched_class
->post_schedule(rq
);
2719 fire_sched_in_preempt_notifiers(current
);
2722 if (unlikely(prev_state
== TASK_DEAD
)) {
2724 * Remove function-return probe instances associated with this
2725 * task and put them back on the free list.
2727 kprobe_flush_task(prev
);
2728 put_task_struct(prev
);
2733 * schedule_tail - first thing a freshly forked thread must call.
2734 * @prev: the thread we just switched away from.
2736 asmlinkage
void schedule_tail(struct task_struct
*prev
)
2737 __releases(rq
->lock
)
2739 struct rq
*rq
= this_rq();
2741 finish_task_switch(rq
, prev
);
2742 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
2743 /* In this case, finish_task_switch does not reenable preemption */
2746 if (current
->set_child_tid
)
2747 put_user(task_pid_vnr(current
), current
->set_child_tid
);
2751 * context_switch - switch to the new MM and the new
2752 * thread's register state.
2755 context_switch(struct rq
*rq
, struct task_struct
*prev
,
2756 struct task_struct
*next
)
2758 struct mm_struct
*mm
, *oldmm
;
2760 prepare_task_switch(rq
, prev
, next
);
2761 trace_sched_switch(rq
, prev
, next
);
2763 oldmm
= prev
->active_mm
;
2765 * For paravirt, this is coupled with an exit in switch_to to
2766 * combine the page table reload and the switch backend into
2769 arch_enter_lazy_cpu_mode();
2771 if (unlikely(!mm
)) {
2772 next
->active_mm
= oldmm
;
2773 atomic_inc(&oldmm
->mm_count
);
2774 enter_lazy_tlb(oldmm
, next
);
2776 switch_mm(oldmm
, mm
, next
);
2778 if (unlikely(!prev
->mm
)) {
2779 prev
->active_mm
= NULL
;
2780 rq
->prev_mm
= oldmm
;
2783 * Since the runqueue lock will be released by the next
2784 * task (which is an invalid locking op but in the case
2785 * of the scheduler it's an obvious special-case), so we
2786 * do an early lockdep release here:
2788 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
2789 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
2792 /* Here we just switch the register state and the stack. */
2793 switch_to(prev
, next
, prev
);
2797 * this_rq must be evaluated again because prev may have moved
2798 * CPUs since it called schedule(), thus the 'rq' on its stack
2799 * frame will be invalid.
2801 finish_task_switch(this_rq(), prev
);
2805 * nr_running, nr_uninterruptible and nr_context_switches:
2807 * externally visible scheduler statistics: current number of runnable
2808 * threads, current number of uninterruptible-sleeping threads, total
2809 * number of context switches performed since bootup.
2811 unsigned long nr_running(void)
2813 unsigned long i
, sum
= 0;
2815 for_each_online_cpu(i
)
2816 sum
+= cpu_rq(i
)->nr_running
;
2821 unsigned long nr_uninterruptible(void)
2823 unsigned long i
, sum
= 0;
2825 for_each_possible_cpu(i
)
2826 sum
+= cpu_rq(i
)->nr_uninterruptible
;
2829 * Since we read the counters lockless, it might be slightly
2830 * inaccurate. Do not allow it to go below zero though:
2832 if (unlikely((long)sum
< 0))
2838 unsigned long long nr_context_switches(void)
2841 unsigned long long sum
= 0;
2843 for_each_possible_cpu(i
)
2844 sum
+= cpu_rq(i
)->nr_switches
;
2849 unsigned long nr_iowait(void)
2851 unsigned long i
, sum
= 0;
2853 for_each_possible_cpu(i
)
2854 sum
+= atomic_read(&cpu_rq(i
)->nr_iowait
);
2859 unsigned long nr_active(void)
2861 unsigned long i
, running
= 0, uninterruptible
= 0;
2863 for_each_online_cpu(i
) {
2864 running
+= cpu_rq(i
)->nr_running
;
2865 uninterruptible
+= cpu_rq(i
)->nr_uninterruptible
;
2868 if (unlikely((long)uninterruptible
< 0))
2869 uninterruptible
= 0;
2871 return running
+ uninterruptible
;
2875 * Update rq->cpu_load[] statistics. This function is usually called every
2876 * scheduler tick (TICK_NSEC).
2878 static void update_cpu_load(struct rq
*this_rq
)
2880 unsigned long this_load
= this_rq
->load
.weight
;
2883 this_rq
->nr_load_updates
++;
2885 /* Update our load: */
2886 for (i
= 0, scale
= 1; i
< CPU_LOAD_IDX_MAX
; i
++, scale
+= scale
) {
2887 unsigned long old_load
, new_load
;
2889 /* scale is effectively 1 << i now, and >> i divides by scale */
2891 old_load
= this_rq
->cpu_load
[i
];
2892 new_load
= this_load
;
2894 * Round up the averaging division if load is increasing. This
2895 * prevents us from getting stuck on 9 if the load is 10, for
2898 if (new_load
> old_load
)
2899 new_load
+= scale
-1;
2900 this_rq
->cpu_load
[i
] = (old_load
*(scale
-1) + new_load
) >> i
;
2907 * double_rq_lock - safely lock two runqueues
2909 * Note this does not disable interrupts like task_rq_lock,
2910 * you need to do so manually before calling.
2912 static void double_rq_lock(struct rq
*rq1
, struct rq
*rq2
)
2913 __acquires(rq1
->lock
)
2914 __acquires(rq2
->lock
)
2916 BUG_ON(!irqs_disabled());
2918 spin_lock(&rq1
->lock
);
2919 __acquire(rq2
->lock
); /* Fake it out ;) */
2922 spin_lock(&rq1
->lock
);
2923 spin_lock_nested(&rq2
->lock
, SINGLE_DEPTH_NESTING
);
2925 spin_lock(&rq2
->lock
);
2926 spin_lock_nested(&rq1
->lock
, SINGLE_DEPTH_NESTING
);
2929 update_rq_clock(rq1
);
2930 update_rq_clock(rq2
);
2934 * double_rq_unlock - safely unlock two runqueues
2936 * Note this does not restore interrupts like task_rq_unlock,
2937 * you need to do so manually after calling.
2939 static void double_rq_unlock(struct rq
*rq1
, struct rq
*rq2
)
2940 __releases(rq1
->lock
)
2941 __releases(rq2
->lock
)
2943 spin_unlock(&rq1
->lock
);
2945 spin_unlock(&rq2
->lock
);
2947 __release(rq2
->lock
);
2951 * If dest_cpu is allowed for this process, migrate the task to it.
2952 * This is accomplished by forcing the cpu_allowed mask to only
2953 * allow dest_cpu, which will force the cpu onto dest_cpu. Then
2954 * the cpu_allowed mask is restored.
2956 static void sched_migrate_task(struct task_struct
*p
, int dest_cpu
)
2958 struct migration_req req
;
2959 unsigned long flags
;
2962 rq
= task_rq_lock(p
, &flags
);
2963 if (!cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
)
2964 || unlikely(!cpu_active(dest_cpu
)))
2967 /* force the process onto the specified CPU */
2968 if (migrate_task(p
, dest_cpu
, &req
)) {
2969 /* Need to wait for migration thread (might exit: take ref). */
2970 struct task_struct
*mt
= rq
->migration_thread
;
2972 get_task_struct(mt
);
2973 task_rq_unlock(rq
, &flags
);
2974 wake_up_process(mt
);
2975 put_task_struct(mt
);
2976 wait_for_completion(&req
.done
);
2981 task_rq_unlock(rq
, &flags
);
2985 * sched_exec - execve() is a valuable balancing opportunity, because at
2986 * this point the task has the smallest effective memory and cache footprint.
2988 void sched_exec(void)
2990 int new_cpu
, this_cpu
= get_cpu();
2991 new_cpu
= sched_balance_self(this_cpu
, SD_BALANCE_EXEC
);
2993 if (new_cpu
!= this_cpu
)
2994 sched_migrate_task(current
, new_cpu
);
2998 * pull_task - move a task from a remote runqueue to the local runqueue.
2999 * Both runqueues must be locked.
3001 static void pull_task(struct rq
*src_rq
, struct task_struct
*p
,
3002 struct rq
*this_rq
, int this_cpu
)
3004 deactivate_task(src_rq
, p
, 0);
3005 set_task_cpu(p
, this_cpu
);
3006 activate_task(this_rq
, p
, 0);
3008 * Note that idle threads have a prio of MAX_PRIO, for this test
3009 * to be always true for them.
3011 check_preempt_curr(this_rq
, p
, 0);
3015 * can_migrate_task - may task p from runqueue rq be migrated to this_cpu?
3018 int can_migrate_task(struct task_struct
*p
, struct rq
*rq
, int this_cpu
,
3019 struct sched_domain
*sd
, enum cpu_idle_type idle
,
3022 int tsk_cache_hot
= 0;
3024 * We do not migrate tasks that are:
3025 * 1) running (obviously), or
3026 * 2) cannot be migrated to this CPU due to cpus_allowed, or
3027 * 3) are cache-hot on their current CPU.
3029 if (!cpumask_test_cpu(this_cpu
, &p
->cpus_allowed
)) {
3030 schedstat_inc(p
, se
.nr_failed_migrations_affine
);
3035 if (task_running(rq
, p
)) {
3036 schedstat_inc(p
, se
.nr_failed_migrations_running
);
3041 * Aggressive migration if:
3042 * 1) task is cache cold, or
3043 * 2) too many balance attempts have failed.
3046 tsk_cache_hot
= task_hot(p
, rq
->clock
, sd
);
3047 if (!tsk_cache_hot
||
3048 sd
->nr_balance_failed
> sd
->cache_nice_tries
) {
3049 #ifdef CONFIG_SCHEDSTATS
3050 if (tsk_cache_hot
) {
3051 schedstat_inc(sd
, lb_hot_gained
[idle
]);
3052 schedstat_inc(p
, se
.nr_forced_migrations
);
3058 if (tsk_cache_hot
) {
3059 schedstat_inc(p
, se
.nr_failed_migrations_hot
);
3065 static unsigned long
3066 balance_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
3067 unsigned long max_load_move
, struct sched_domain
*sd
,
3068 enum cpu_idle_type idle
, int *all_pinned
,
3069 int *this_best_prio
, struct rq_iterator
*iterator
)
3071 int loops
= 0, pulled
= 0, pinned
= 0;
3072 struct task_struct
*p
;
3073 long rem_load_move
= max_load_move
;
3075 if (max_load_move
== 0)
3081 * Start the load-balancing iterator:
3083 p
= iterator
->start(iterator
->arg
);
3085 if (!p
|| loops
++ > sysctl_sched_nr_migrate
)
3088 if ((p
->se
.load
.weight
>> 1) > rem_load_move
||
3089 !can_migrate_task(p
, busiest
, this_cpu
, sd
, idle
, &pinned
)) {
3090 p
= iterator
->next(iterator
->arg
);
3094 pull_task(busiest
, p
, this_rq
, this_cpu
);
3096 rem_load_move
-= p
->se
.load
.weight
;
3098 #ifdef CONFIG_PREEMPT
3100 * NEWIDLE balancing is a source of latency, so preemptible kernels
3101 * will stop after the first task is pulled to minimize the critical
3104 if (idle
== CPU_NEWLY_IDLE
)
3109 * We only want to steal up to the prescribed amount of weighted load.
3111 if (rem_load_move
> 0) {
3112 if (p
->prio
< *this_best_prio
)
3113 *this_best_prio
= p
->prio
;
3114 p
= iterator
->next(iterator
->arg
);
3119 * Right now, this is one of only two places pull_task() is called,
3120 * so we can safely collect pull_task() stats here rather than
3121 * inside pull_task().
3123 schedstat_add(sd
, lb_gained
[idle
], pulled
);
3126 *all_pinned
= pinned
;
3128 return max_load_move
- rem_load_move
;
3132 * move_tasks tries to move up to max_load_move weighted load from busiest to
3133 * this_rq, as part of a balancing operation within domain "sd".
3134 * Returns 1 if successful and 0 otherwise.
3136 * Called with both runqueues locked.
3138 static int move_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
3139 unsigned long max_load_move
,
3140 struct sched_domain
*sd
, enum cpu_idle_type idle
,
3143 const struct sched_class
*class = sched_class_highest
;
3144 unsigned long total_load_moved
= 0;
3145 int this_best_prio
= this_rq
->curr
->prio
;
3149 class->load_balance(this_rq
, this_cpu
, busiest
,
3150 max_load_move
- total_load_moved
,
3151 sd
, idle
, all_pinned
, &this_best_prio
);
3152 class = class->next
;
3154 #ifdef CONFIG_PREEMPT
3156 * NEWIDLE balancing is a source of latency, so preemptible
3157 * kernels will stop after the first task is pulled to minimize
3158 * the critical section.
3160 if (idle
== CPU_NEWLY_IDLE
&& this_rq
->nr_running
)
3163 } while (class && max_load_move
> total_load_moved
);
3165 return total_load_moved
> 0;
3169 iter_move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
3170 struct sched_domain
*sd
, enum cpu_idle_type idle
,
3171 struct rq_iterator
*iterator
)
3173 struct task_struct
*p
= iterator
->start(iterator
->arg
);
3177 if (can_migrate_task(p
, busiest
, this_cpu
, sd
, idle
, &pinned
)) {
3178 pull_task(busiest
, p
, this_rq
, this_cpu
);
3180 * Right now, this is only the second place pull_task()
3181 * is called, so we can safely collect pull_task()
3182 * stats here rather than inside pull_task().
3184 schedstat_inc(sd
, lb_gained
[idle
]);
3188 p
= iterator
->next(iterator
->arg
);
3195 * move_one_task tries to move exactly one task from busiest to this_rq, as
3196 * part of active balancing operations within "domain".
3197 * Returns 1 if successful and 0 otherwise.
3199 * Called with both runqueues locked.
3201 static int move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
3202 struct sched_domain
*sd
, enum cpu_idle_type idle
)
3204 const struct sched_class
*class;
3206 for (class = sched_class_highest
; class; class = class->next
)
3207 if (class->move_one_task(this_rq
, this_cpu
, busiest
, sd
, idle
))
3212 /********** Helpers for find_busiest_group ************************/
3214 * sd_lb_stats - Structure to store the statistics of a sched_domain
3215 * during load balancing.
3217 struct sd_lb_stats
{
3218 struct sched_group
*busiest
; /* Busiest group in this sd */
3219 struct sched_group
*this; /* Local group in this sd */
3220 unsigned long total_load
; /* Total load of all groups in sd */
3221 unsigned long total_pwr
; /* Total power of all groups in sd */
3222 unsigned long avg_load
; /* Average load across all groups in sd */
3224 /** Statistics of this group */
3225 unsigned long this_load
;
3226 unsigned long this_load_per_task
;
3227 unsigned long this_nr_running
;
3229 /* Statistics of the busiest group */
3230 unsigned long max_load
;
3231 unsigned long busiest_load_per_task
;
3232 unsigned long busiest_nr_running
;
3234 int group_imb
; /* Is there imbalance in this sd */
3235 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3236 int power_savings_balance
; /* Is powersave balance needed for this sd */
3237 struct sched_group
*group_min
; /* Least loaded group in sd */
3238 struct sched_group
*group_leader
; /* Group which relieves group_min */
3239 unsigned long min_load_per_task
; /* load_per_task in group_min */
3240 unsigned long leader_nr_running
; /* Nr running of group_leader */
3241 unsigned long min_nr_running
; /* Nr running of group_min */
3246 * sg_lb_stats - stats of a sched_group required for load_balancing
3248 struct sg_lb_stats
{
3249 unsigned long avg_load
; /*Avg load across the CPUs of the group */
3250 unsigned long group_load
; /* Total load over the CPUs of the group */
3251 unsigned long sum_nr_running
; /* Nr tasks running in the group */
3252 unsigned long sum_weighted_load
; /* Weighted load of group's tasks */
3253 unsigned long group_capacity
;
3254 int group_imb
; /* Is there an imbalance in the group ? */
3258 * group_first_cpu - Returns the first cpu in the cpumask of a sched_group.
3259 * @group: The group whose first cpu is to be returned.
3261 static inline unsigned int group_first_cpu(struct sched_group
*group
)
3263 return cpumask_first(sched_group_cpus(group
));
3267 * get_sd_load_idx - Obtain the load index for a given sched domain.
3268 * @sd: The sched_domain whose load_idx is to be obtained.
3269 * @idle: The Idle status of the CPU for whose sd load_icx is obtained.
3271 static inline int get_sd_load_idx(struct sched_domain
*sd
,
3272 enum cpu_idle_type idle
)
3278 load_idx
= sd
->busy_idx
;
3281 case CPU_NEWLY_IDLE
:
3282 load_idx
= sd
->newidle_idx
;
3285 load_idx
= sd
->idle_idx
;
3293 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3295 * init_sd_power_savings_stats - Initialize power savings statistics for
3296 * the given sched_domain, during load balancing.
3298 * @sd: Sched domain whose power-savings statistics are to be initialized.
3299 * @sds: Variable containing the statistics for sd.
3300 * @idle: Idle status of the CPU at which we're performing load-balancing.
3302 static inline void init_sd_power_savings_stats(struct sched_domain
*sd
,
3303 struct sd_lb_stats
*sds
, enum cpu_idle_type idle
)
3306 * Busy processors will not participate in power savings
3309 if (idle
== CPU_NOT_IDLE
|| !(sd
->flags
& SD_POWERSAVINGS_BALANCE
))
3310 sds
->power_savings_balance
= 0;
3312 sds
->power_savings_balance
= 1;
3313 sds
->min_nr_running
= ULONG_MAX
;
3314 sds
->leader_nr_running
= 0;
3319 * update_sd_power_savings_stats - Update the power saving stats for a
3320 * sched_domain while performing load balancing.
3322 * @group: sched_group belonging to the sched_domain under consideration.
3323 * @sds: Variable containing the statistics of the sched_domain
3324 * @local_group: Does group contain the CPU for which we're performing
3326 * @sgs: Variable containing the statistics of the group.
3328 static inline void update_sd_power_savings_stats(struct sched_group
*group
,
3329 struct sd_lb_stats
*sds
, int local_group
, struct sg_lb_stats
*sgs
)
3332 if (!sds
->power_savings_balance
)
3336 * If the local group is idle or completely loaded
3337 * no need to do power savings balance at this domain
3339 if (local_group
&& (sds
->this_nr_running
>= sgs
->group_capacity
||
3340 !sds
->this_nr_running
))
3341 sds
->power_savings_balance
= 0;
3344 * If a group is already running at full capacity or idle,
3345 * don't include that group in power savings calculations
3347 if (!sds
->power_savings_balance
||
3348 sgs
->sum_nr_running
>= sgs
->group_capacity
||
3349 !sgs
->sum_nr_running
)
3353 * Calculate the group which has the least non-idle load.
3354 * This is the group from where we need to pick up the load
3357 if ((sgs
->sum_nr_running
< sds
->min_nr_running
) ||
3358 (sgs
->sum_nr_running
== sds
->min_nr_running
&&
3359 group_first_cpu(group
) > group_first_cpu(sds
->group_min
))) {
3360 sds
->group_min
= group
;
3361 sds
->min_nr_running
= sgs
->sum_nr_running
;
3362 sds
->min_load_per_task
= sgs
->sum_weighted_load
/
3363 sgs
->sum_nr_running
;
3367 * Calculate the group which is almost near its
3368 * capacity but still has some space to pick up some load
3369 * from other group and save more power
3371 if (sgs
->sum_nr_running
> sgs
->group_capacity
- 1)
3374 if (sgs
->sum_nr_running
> sds
->leader_nr_running
||
3375 (sgs
->sum_nr_running
== sds
->leader_nr_running
&&
3376 group_first_cpu(group
) < group_first_cpu(sds
->group_leader
))) {
3377 sds
->group_leader
= group
;
3378 sds
->leader_nr_running
= sgs
->sum_nr_running
;
3383 * check_power_save_busiest_group - see if there is potential for some power-savings balance
3384 * @sds: Variable containing the statistics of the sched_domain
3385 * under consideration.
3386 * @this_cpu: Cpu at which we're currently performing load-balancing.
3387 * @imbalance: Variable to store the imbalance.
3390 * Check if we have potential to perform some power-savings balance.
3391 * If yes, set the busiest group to be the least loaded group in the
3392 * sched_domain, so that it's CPUs can be put to idle.
3394 * Returns 1 if there is potential to perform power-savings balance.
3397 static inline int check_power_save_busiest_group(struct sd_lb_stats
*sds
,
3398 int this_cpu
, unsigned long *imbalance
)
3400 if (!sds
->power_savings_balance
)
3403 if (sds
->this != sds
->group_leader
||
3404 sds
->group_leader
== sds
->group_min
)
3407 *imbalance
= sds
->min_load_per_task
;
3408 sds
->busiest
= sds
->group_min
;
3410 if (sched_mc_power_savings
>= POWERSAVINGS_BALANCE_WAKEUP
) {
3411 cpu_rq(this_cpu
)->rd
->sched_mc_preferred_wakeup_cpu
=
3412 group_first_cpu(sds
->group_leader
);
3418 #else /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
3419 static inline void init_sd_power_savings_stats(struct sched_domain
*sd
,
3420 struct sd_lb_stats
*sds
, enum cpu_idle_type idle
)
3425 static inline void update_sd_power_savings_stats(struct sched_group
*group
,
3426 struct sd_lb_stats
*sds
, int local_group
, struct sg_lb_stats
*sgs
)
3431 static inline int check_power_save_busiest_group(struct sd_lb_stats
*sds
,
3432 int this_cpu
, unsigned long *imbalance
)
3436 #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
3440 * update_sg_lb_stats - Update sched_group's statistics for load balancing.
3441 * @group: sched_group whose statistics are to be updated.
3442 * @this_cpu: Cpu for which load balance is currently performed.
3443 * @idle: Idle status of this_cpu
3444 * @load_idx: Load index of sched_domain of this_cpu for load calc.
3445 * @sd_idle: Idle status of the sched_domain containing group.
3446 * @local_group: Does group contain this_cpu.
3447 * @cpus: Set of cpus considered for load balancing.
3448 * @balance: Should we balance.
3449 * @sgs: variable to hold the statistics for this group.
3451 static inline void update_sg_lb_stats(struct sched_group
*group
, int this_cpu
,
3452 enum cpu_idle_type idle
, int load_idx
, int *sd_idle
,
3453 int local_group
, const struct cpumask
*cpus
,
3454 int *balance
, struct sg_lb_stats
*sgs
)
3456 unsigned long load
, max_cpu_load
, min_cpu_load
;
3458 unsigned int balance_cpu
= -1, first_idle_cpu
= 0;
3459 unsigned long sum_avg_load_per_task
;
3460 unsigned long avg_load_per_task
;
3463 balance_cpu
= group_first_cpu(group
);
3465 /* Tally up the load of all CPUs in the group */
3466 sum_avg_load_per_task
= avg_load_per_task
= 0;
3468 min_cpu_load
= ~0UL;
3470 for_each_cpu_and(i
, sched_group_cpus(group
), cpus
) {
3471 struct rq
*rq
= cpu_rq(i
);
3473 if (*sd_idle
&& rq
->nr_running
)
3476 /* Bias balancing toward cpus of our domain */
3478 if (idle_cpu(i
) && !first_idle_cpu
) {
3483 load
= target_load(i
, load_idx
);
3485 load
= source_load(i
, load_idx
);
3486 if (load
> max_cpu_load
)
3487 max_cpu_load
= load
;
3488 if (min_cpu_load
> load
)
3489 min_cpu_load
= load
;
3492 sgs
->group_load
+= load
;
3493 sgs
->sum_nr_running
+= rq
->nr_running
;
3494 sgs
->sum_weighted_load
+= weighted_cpuload(i
);
3496 sum_avg_load_per_task
+= cpu_avg_load_per_task(i
);
3500 * First idle cpu or the first cpu(busiest) in this sched group
3501 * is eligible for doing load balancing at this and above
3502 * domains. In the newly idle case, we will allow all the cpu's
3503 * to do the newly idle load balance.
3505 if (idle
!= CPU_NEWLY_IDLE
&& local_group
&&
3506 balance_cpu
!= this_cpu
&& balance
) {
3511 /* Adjust by relative CPU power of the group */
3512 sgs
->avg_load
= sg_div_cpu_power(group
,
3513 sgs
->group_load
* SCHED_LOAD_SCALE
);
3517 * Consider the group unbalanced when the imbalance is larger
3518 * than the average weight of two tasks.
3520 * APZ: with cgroup the avg task weight can vary wildly and
3521 * might not be a suitable number - should we keep a
3522 * normalized nr_running number somewhere that negates
3525 avg_load_per_task
= sg_div_cpu_power(group
,
3526 sum_avg_load_per_task
* SCHED_LOAD_SCALE
);
3528 if ((max_cpu_load
- min_cpu_load
) > 2*avg_load_per_task
)
3531 sgs
->group_capacity
= group
->__cpu_power
/ SCHED_LOAD_SCALE
;
3536 * update_sd_lb_stats - Update sched_group's statistics for load balancing.
3537 * @sd: sched_domain whose statistics are to be updated.
3538 * @this_cpu: Cpu for which load balance is currently performed.
3539 * @idle: Idle status of this_cpu
3540 * @sd_idle: Idle status of the sched_domain containing group.
3541 * @cpus: Set of cpus considered for load balancing.
3542 * @balance: Should we balance.
3543 * @sds: variable to hold the statistics for this sched_domain.
3545 static inline void update_sd_lb_stats(struct sched_domain
*sd
, int this_cpu
,
3546 enum cpu_idle_type idle
, int *sd_idle
,
3547 const struct cpumask
*cpus
, int *balance
,
3548 struct sd_lb_stats
*sds
)
3550 struct sched_group
*group
= sd
->groups
;
3551 struct sg_lb_stats sgs
;
3554 init_sd_power_savings_stats(sd
, sds
, idle
);
3555 load_idx
= get_sd_load_idx(sd
, idle
);
3560 local_group
= cpumask_test_cpu(this_cpu
,
3561 sched_group_cpus(group
));
3562 memset(&sgs
, 0, sizeof(sgs
));
3563 update_sg_lb_stats(group
, this_cpu
, idle
, load_idx
, sd_idle
,
3564 local_group
, cpus
, balance
, &sgs
);
3566 if (local_group
&& balance
&& !(*balance
))
3569 sds
->total_load
+= sgs
.group_load
;
3570 sds
->total_pwr
+= group
->__cpu_power
;
3573 sds
->this_load
= sgs
.avg_load
;
3575 sds
->this_nr_running
= sgs
.sum_nr_running
;
3576 sds
->this_load_per_task
= sgs
.sum_weighted_load
;
3577 } else if (sgs
.avg_load
> sds
->max_load
&&
3578 (sgs
.sum_nr_running
> sgs
.group_capacity
||
3580 sds
->max_load
= sgs
.avg_load
;
3581 sds
->busiest
= group
;
3582 sds
->busiest_nr_running
= sgs
.sum_nr_running
;
3583 sds
->busiest_load_per_task
= sgs
.sum_weighted_load
;
3584 sds
->group_imb
= sgs
.group_imb
;
3587 update_sd_power_savings_stats(group
, sds
, local_group
, &sgs
);
3588 group
= group
->next
;
3589 } while (group
!= sd
->groups
);
3594 * fix_small_imbalance - Calculate the minor imbalance that exists
3595 * amongst the groups of a sched_domain, during
3597 * @sds: Statistics of the sched_domain whose imbalance is to be calculated.
3598 * @this_cpu: The cpu at whose sched_domain we're performing load-balance.
3599 * @imbalance: Variable to store the imbalance.
3601 static inline void fix_small_imbalance(struct sd_lb_stats
*sds
,
3602 int this_cpu
, unsigned long *imbalance
)
3604 unsigned long tmp
, pwr_now
= 0, pwr_move
= 0;
3605 unsigned int imbn
= 2;
3607 if (sds
->this_nr_running
) {
3608 sds
->this_load_per_task
/= sds
->this_nr_running
;
3609 if (sds
->busiest_load_per_task
>
3610 sds
->this_load_per_task
)
3613 sds
->this_load_per_task
=
3614 cpu_avg_load_per_task(this_cpu
);
3616 if (sds
->max_load
- sds
->this_load
+ sds
->busiest_load_per_task
>=
3617 sds
->busiest_load_per_task
* imbn
) {
3618 *imbalance
= sds
->busiest_load_per_task
;
3623 * OK, we don't have enough imbalance to justify moving tasks,
3624 * however we may be able to increase total CPU power used by
3628 pwr_now
+= sds
->busiest
->__cpu_power
*
3629 min(sds
->busiest_load_per_task
, sds
->max_load
);
3630 pwr_now
+= sds
->this->__cpu_power
*
3631 min(sds
->this_load_per_task
, sds
->this_load
);
3632 pwr_now
/= SCHED_LOAD_SCALE
;
3634 /* Amount of load we'd subtract */
3635 tmp
= sg_div_cpu_power(sds
->busiest
,
3636 sds
->busiest_load_per_task
* SCHED_LOAD_SCALE
);
3637 if (sds
->max_load
> tmp
)
3638 pwr_move
+= sds
->busiest
->__cpu_power
*
3639 min(sds
->busiest_load_per_task
, sds
->max_load
- tmp
);
3641 /* Amount of load we'd add */
3642 if (sds
->max_load
* sds
->busiest
->__cpu_power
<
3643 sds
->busiest_load_per_task
* SCHED_LOAD_SCALE
)
3644 tmp
= sg_div_cpu_power(sds
->this,
3645 sds
->max_load
* sds
->busiest
->__cpu_power
);
3647 tmp
= sg_div_cpu_power(sds
->this,
3648 sds
->busiest_load_per_task
* SCHED_LOAD_SCALE
);
3649 pwr_move
+= sds
->this->__cpu_power
*
3650 min(sds
->this_load_per_task
, sds
->this_load
+ tmp
);
3651 pwr_move
/= SCHED_LOAD_SCALE
;
3653 /* Move if we gain throughput */
3654 if (pwr_move
> pwr_now
)
3655 *imbalance
= sds
->busiest_load_per_task
;
3659 * calculate_imbalance - Calculate the amount of imbalance present within the
3660 * groups of a given sched_domain during load balance.
3661 * @sds: statistics of the sched_domain whose imbalance is to be calculated.
3662 * @this_cpu: Cpu for which currently load balance is being performed.
3663 * @imbalance: The variable to store the imbalance.
3665 static inline void calculate_imbalance(struct sd_lb_stats
*sds
, int this_cpu
,
3666 unsigned long *imbalance
)
3668 unsigned long max_pull
;
3670 * In the presence of smp nice balancing, certain scenarios can have
3671 * max load less than avg load(as we skip the groups at or below
3672 * its cpu_power, while calculating max_load..)
3674 if (sds
->max_load
< sds
->avg_load
) {
3676 return fix_small_imbalance(sds
, this_cpu
, imbalance
);
3679 /* Don't want to pull so many tasks that a group would go idle */
3680 max_pull
= min(sds
->max_load
- sds
->avg_load
,
3681 sds
->max_load
- sds
->busiest_load_per_task
);
3683 /* How much load to actually move to equalise the imbalance */
3684 *imbalance
= min(max_pull
* sds
->busiest
->__cpu_power
,
3685 (sds
->avg_load
- sds
->this_load
) * sds
->this->__cpu_power
)
3689 * if *imbalance is less than the average load per runnable task
3690 * there is no gaurantee that any tasks will be moved so we'll have
3691 * a think about bumping its value to force at least one task to be
3694 if (*imbalance
< sds
->busiest_load_per_task
)
3695 return fix_small_imbalance(sds
, this_cpu
, imbalance
);
3698 /******* find_busiest_group() helpers end here *********************/
3701 * find_busiest_group - Returns the busiest group within the sched_domain
3702 * if there is an imbalance. If there isn't an imbalance, and
3703 * the user has opted for power-savings, it returns a group whose
3704 * CPUs can be put to idle by rebalancing those tasks elsewhere, if
3705 * such a group exists.
3707 * Also calculates the amount of weighted load which should be moved
3708 * to restore balance.
3710 * @sd: The sched_domain whose busiest group is to be returned.
3711 * @this_cpu: The cpu for which load balancing is currently being performed.
3712 * @imbalance: Variable which stores amount of weighted load which should
3713 * be moved to restore balance/put a group to idle.
3714 * @idle: The idle status of this_cpu.
3715 * @sd_idle: The idleness of sd
3716 * @cpus: The set of CPUs under consideration for load-balancing.
3717 * @balance: Pointer to a variable indicating if this_cpu
3718 * is the appropriate cpu to perform load balancing at this_level.
3720 * Returns: - the busiest group if imbalance exists.
3721 * - If no imbalance and user has opted for power-savings balance,
3722 * return the least loaded group whose CPUs can be
3723 * put to idle by rebalancing its tasks onto our group.
3725 static struct sched_group
*
3726 find_busiest_group(struct sched_domain
*sd
, int this_cpu
,
3727 unsigned long *imbalance
, enum cpu_idle_type idle
,
3728 int *sd_idle
, const struct cpumask
*cpus
, int *balance
)
3730 struct sd_lb_stats sds
;
3732 memset(&sds
, 0, sizeof(sds
));
3735 * Compute the various statistics relavent for load balancing at
3738 update_sd_lb_stats(sd
, this_cpu
, idle
, sd_idle
, cpus
,
3741 /* Cases where imbalance does not exist from POV of this_cpu */
3742 /* 1) this_cpu is not the appropriate cpu to perform load balancing
3744 * 2) There is no busy sibling group to pull from.
3745 * 3) This group is the busiest group.
3746 * 4) This group is more busy than the avg busieness at this
3748 * 5) The imbalance is within the specified limit.
3749 * 6) Any rebalance would lead to ping-pong
3751 if (balance
&& !(*balance
))
3754 if (!sds
.busiest
|| sds
.busiest_nr_running
== 0)
3757 if (sds
.this_load
>= sds
.max_load
)
3760 sds
.avg_load
= (SCHED_LOAD_SCALE
* sds
.total_load
) / sds
.total_pwr
;
3762 if (sds
.this_load
>= sds
.avg_load
)
3765 if (100 * sds
.max_load
<= sd
->imbalance_pct
* sds
.this_load
)
3768 sds
.busiest_load_per_task
/= sds
.busiest_nr_running
;
3770 sds
.busiest_load_per_task
=
3771 min(sds
.busiest_load_per_task
, sds
.avg_load
);
3774 * We're trying to get all the cpus to the average_load, so we don't
3775 * want to push ourselves above the average load, nor do we wish to
3776 * reduce the max loaded cpu below the average load, as either of these
3777 * actions would just result in more rebalancing later, and ping-pong
3778 * tasks around. Thus we look for the minimum possible imbalance.
3779 * Negative imbalances (*we* are more loaded than anyone else) will
3780 * be counted as no imbalance for these purposes -- we can't fix that
3781 * by pulling tasks to us. Be careful of negative numbers as they'll
3782 * appear as very large values with unsigned longs.
3784 if (sds
.max_load
<= sds
.busiest_load_per_task
)
3787 /* Looks like there is an imbalance. Compute it */
3788 calculate_imbalance(&sds
, this_cpu
, imbalance
);
3793 * There is no obvious imbalance. But check if we can do some balancing
3796 if (check_power_save_busiest_group(&sds
, this_cpu
, imbalance
))
3804 * find_busiest_queue - find the busiest runqueue among the cpus in group.
3807 find_busiest_queue(struct sched_group
*group
, enum cpu_idle_type idle
,
3808 unsigned long imbalance
, const struct cpumask
*cpus
)
3810 struct rq
*busiest
= NULL
, *rq
;
3811 unsigned long max_load
= 0;
3814 for_each_cpu(i
, sched_group_cpus(group
)) {
3817 if (!cpumask_test_cpu(i
, cpus
))
3821 wl
= weighted_cpuload(i
);
3823 if (rq
->nr_running
== 1 && wl
> imbalance
)
3826 if (wl
> max_load
) {
3836 * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but
3837 * so long as it is large enough.
3839 #define MAX_PINNED_INTERVAL 512
3841 /* Working cpumask for load_balance and load_balance_newidle. */
3842 static DEFINE_PER_CPU(cpumask_var_t
, load_balance_tmpmask
);
3845 * Check this_cpu to ensure it is balanced within domain. Attempt to move
3846 * tasks if there is an imbalance.
3848 static int load_balance(int this_cpu
, struct rq
*this_rq
,
3849 struct sched_domain
*sd
, enum cpu_idle_type idle
,
3852 int ld_moved
, all_pinned
= 0, active_balance
= 0, sd_idle
= 0;
3853 struct sched_group
*group
;
3854 unsigned long imbalance
;
3856 unsigned long flags
;
3857 struct cpumask
*cpus
= __get_cpu_var(load_balance_tmpmask
);
3859 cpumask_setall(cpus
);
3862 * When power savings policy is enabled for the parent domain, idle
3863 * sibling can pick up load irrespective of busy siblings. In this case,
3864 * let the state of idle sibling percolate up as CPU_IDLE, instead of
3865 * portraying it as CPU_NOT_IDLE.
3867 if (idle
!= CPU_NOT_IDLE
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3868 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3871 schedstat_inc(sd
, lb_count
[idle
]);
3875 group
= find_busiest_group(sd
, this_cpu
, &imbalance
, idle
, &sd_idle
,
3882 schedstat_inc(sd
, lb_nobusyg
[idle
]);
3886 busiest
= find_busiest_queue(group
, idle
, imbalance
, cpus
);
3888 schedstat_inc(sd
, lb_nobusyq
[idle
]);
3892 BUG_ON(busiest
== this_rq
);
3894 schedstat_add(sd
, lb_imbalance
[idle
], imbalance
);
3897 if (busiest
->nr_running
> 1) {
3899 * Attempt to move tasks. If find_busiest_group has found
3900 * an imbalance but busiest->nr_running <= 1, the group is
3901 * still unbalanced. ld_moved simply stays zero, so it is
3902 * correctly treated as an imbalance.
3904 local_irq_save(flags
);
3905 double_rq_lock(this_rq
, busiest
);
3906 ld_moved
= move_tasks(this_rq
, this_cpu
, busiest
,
3907 imbalance
, sd
, idle
, &all_pinned
);
3908 double_rq_unlock(this_rq
, busiest
);
3909 local_irq_restore(flags
);
3912 * some other cpu did the load balance for us.
3914 if (ld_moved
&& this_cpu
!= smp_processor_id())
3915 resched_cpu(this_cpu
);
3917 /* All tasks on this runqueue were pinned by CPU affinity */
3918 if (unlikely(all_pinned
)) {
3919 cpumask_clear_cpu(cpu_of(busiest
), cpus
);
3920 if (!cpumask_empty(cpus
))
3927 schedstat_inc(sd
, lb_failed
[idle
]);
3928 sd
->nr_balance_failed
++;
3930 if (unlikely(sd
->nr_balance_failed
> sd
->cache_nice_tries
+2)) {
3932 spin_lock_irqsave(&busiest
->lock
, flags
);
3934 /* don't kick the migration_thread, if the curr
3935 * task on busiest cpu can't be moved to this_cpu
3937 if (!cpumask_test_cpu(this_cpu
,
3938 &busiest
->curr
->cpus_allowed
)) {
3939 spin_unlock_irqrestore(&busiest
->lock
, flags
);
3941 goto out_one_pinned
;
3944 if (!busiest
->active_balance
) {
3945 busiest
->active_balance
= 1;
3946 busiest
->push_cpu
= this_cpu
;
3949 spin_unlock_irqrestore(&busiest
->lock
, flags
);
3951 wake_up_process(busiest
->migration_thread
);
3954 * We've kicked active balancing, reset the failure
3957 sd
->nr_balance_failed
= sd
->cache_nice_tries
+1;
3960 sd
->nr_balance_failed
= 0;
3962 if (likely(!active_balance
)) {
3963 /* We were unbalanced, so reset the balancing interval */
3964 sd
->balance_interval
= sd
->min_interval
;
3967 * If we've begun active balancing, start to back off. This
3968 * case may not be covered by the all_pinned logic if there
3969 * is only 1 task on the busy runqueue (because we don't call
3972 if (sd
->balance_interval
< sd
->max_interval
)
3973 sd
->balance_interval
*= 2;
3976 if (!ld_moved
&& !sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3977 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3983 schedstat_inc(sd
, lb_balanced
[idle
]);
3985 sd
->nr_balance_failed
= 0;
3988 /* tune up the balancing interval */
3989 if ((all_pinned
&& sd
->balance_interval
< MAX_PINNED_INTERVAL
) ||
3990 (sd
->balance_interval
< sd
->max_interval
))
3991 sd
->balance_interval
*= 2;
3993 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3994 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
4005 * Check this_cpu to ensure it is balanced within domain. Attempt to move
4006 * tasks if there is an imbalance.
4008 * Called from schedule when this_rq is about to become idle (CPU_NEWLY_IDLE).
4009 * this_rq is locked.
4012 load_balance_newidle(int this_cpu
, struct rq
*this_rq
, struct sched_domain
*sd
)
4014 struct sched_group
*group
;
4015 struct rq
*busiest
= NULL
;
4016 unsigned long imbalance
;
4020 struct cpumask
*cpus
= __get_cpu_var(load_balance_tmpmask
);
4022 cpumask_setall(cpus
);
4025 * When power savings policy is enabled for the parent domain, idle
4026 * sibling can pick up load irrespective of busy siblings. In this case,
4027 * let the state of idle sibling percolate up as IDLE, instead of
4028 * portraying it as CPU_NOT_IDLE.
4030 if (sd
->flags
& SD_SHARE_CPUPOWER
&&
4031 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
4034 schedstat_inc(sd
, lb_count
[CPU_NEWLY_IDLE
]);
4036 update_shares_locked(this_rq
, sd
);
4037 group
= find_busiest_group(sd
, this_cpu
, &imbalance
, CPU_NEWLY_IDLE
,
4038 &sd_idle
, cpus
, NULL
);
4040 schedstat_inc(sd
, lb_nobusyg
[CPU_NEWLY_IDLE
]);
4044 busiest
= find_busiest_queue(group
, CPU_NEWLY_IDLE
, imbalance
, cpus
);
4046 schedstat_inc(sd
, lb_nobusyq
[CPU_NEWLY_IDLE
]);
4050 BUG_ON(busiest
== this_rq
);
4052 schedstat_add(sd
, lb_imbalance
[CPU_NEWLY_IDLE
], imbalance
);
4055 if (busiest
->nr_running
> 1) {
4056 /* Attempt to move tasks */
4057 double_lock_balance(this_rq
, busiest
);
4058 /* this_rq->clock is already updated */
4059 update_rq_clock(busiest
);
4060 ld_moved
= move_tasks(this_rq
, this_cpu
, busiest
,
4061 imbalance
, sd
, CPU_NEWLY_IDLE
,
4063 double_unlock_balance(this_rq
, busiest
);
4065 if (unlikely(all_pinned
)) {
4066 cpumask_clear_cpu(cpu_of(busiest
), cpus
);
4067 if (!cpumask_empty(cpus
))
4073 int active_balance
= 0;
4075 schedstat_inc(sd
, lb_failed
[CPU_NEWLY_IDLE
]);
4076 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
4077 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
4080 if (sched_mc_power_savings
< POWERSAVINGS_BALANCE_WAKEUP
)
4083 if (sd
->nr_balance_failed
++ < 2)
4087 * The only task running in a non-idle cpu can be moved to this
4088 * cpu in an attempt to completely freeup the other CPU
4089 * package. The same method used to move task in load_balance()
4090 * have been extended for load_balance_newidle() to speedup
4091 * consolidation at sched_mc=POWERSAVINGS_BALANCE_WAKEUP (2)
4093 * The package power saving logic comes from
4094 * find_busiest_group(). If there are no imbalance, then
4095 * f_b_g() will return NULL. However when sched_mc={1,2} then
4096 * f_b_g() will select a group from which a running task may be
4097 * pulled to this cpu in order to make the other package idle.
4098 * If there is no opportunity to make a package idle and if
4099 * there are no imbalance, then f_b_g() will return NULL and no
4100 * action will be taken in load_balance_newidle().
4102 * Under normal task pull operation due to imbalance, there
4103 * will be more than one task in the source run queue and
4104 * move_tasks() will succeed. ld_moved will be true and this
4105 * active balance code will not be triggered.
4108 /* Lock busiest in correct order while this_rq is held */
4109 double_lock_balance(this_rq
, busiest
);
4112 * don't kick the migration_thread, if the curr
4113 * task on busiest cpu can't be moved to this_cpu
4115 if (!cpumask_test_cpu(this_cpu
, &busiest
->curr
->cpus_allowed
)) {
4116 double_unlock_balance(this_rq
, busiest
);
4121 if (!busiest
->active_balance
) {
4122 busiest
->active_balance
= 1;
4123 busiest
->push_cpu
= this_cpu
;
4127 double_unlock_balance(this_rq
, busiest
);
4129 * Should not call ttwu while holding a rq->lock
4131 spin_unlock(&this_rq
->lock
);
4133 wake_up_process(busiest
->migration_thread
);
4134 spin_lock(&this_rq
->lock
);
4137 sd
->nr_balance_failed
= 0;
4139 update_shares_locked(this_rq
, sd
);
4143 schedstat_inc(sd
, lb_balanced
[CPU_NEWLY_IDLE
]);
4144 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
4145 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
4147 sd
->nr_balance_failed
= 0;
4153 * idle_balance is called by schedule() if this_cpu is about to become
4154 * idle. Attempts to pull tasks from other CPUs.
4156 static void idle_balance(int this_cpu
, struct rq
*this_rq
)
4158 struct sched_domain
*sd
;
4159 int pulled_task
= 0;
4160 unsigned long next_balance
= jiffies
+ HZ
;
4162 for_each_domain(this_cpu
, sd
) {
4163 unsigned long interval
;
4165 if (!(sd
->flags
& SD_LOAD_BALANCE
))
4168 if (sd
->flags
& SD_BALANCE_NEWIDLE
)
4169 /* If we've pulled tasks over stop searching: */
4170 pulled_task
= load_balance_newidle(this_cpu
, this_rq
,
4173 interval
= msecs_to_jiffies(sd
->balance_interval
);
4174 if (time_after(next_balance
, sd
->last_balance
+ interval
))
4175 next_balance
= sd
->last_balance
+ interval
;
4179 if (pulled_task
|| time_after(jiffies
, this_rq
->next_balance
)) {
4181 * We are going idle. next_balance may be set based on
4182 * a busy processor. So reset next_balance.
4184 this_rq
->next_balance
= next_balance
;
4189 * active_load_balance is run by migration threads. It pushes running tasks
4190 * off the busiest CPU onto idle CPUs. It requires at least 1 task to be
4191 * running on each physical CPU where possible, and avoids physical /
4192 * logical imbalances.
4194 * Called with busiest_rq locked.
4196 static void active_load_balance(struct rq
*busiest_rq
, int busiest_cpu
)
4198 int target_cpu
= busiest_rq
->push_cpu
;
4199 struct sched_domain
*sd
;
4200 struct rq
*target_rq
;
4202 /* Is there any task to move? */
4203 if (busiest_rq
->nr_running
<= 1)
4206 target_rq
= cpu_rq(target_cpu
);
4209 * This condition is "impossible", if it occurs
4210 * we need to fix it. Originally reported by
4211 * Bjorn Helgaas on a 128-cpu setup.
4213 BUG_ON(busiest_rq
== target_rq
);
4215 /* move a task from busiest_rq to target_rq */
4216 double_lock_balance(busiest_rq
, target_rq
);
4217 update_rq_clock(busiest_rq
);
4218 update_rq_clock(target_rq
);
4220 /* Search for an sd spanning us and the target CPU. */
4221 for_each_domain(target_cpu
, sd
) {
4222 if ((sd
->flags
& SD_LOAD_BALANCE
) &&
4223 cpumask_test_cpu(busiest_cpu
, sched_domain_span(sd
)))
4228 schedstat_inc(sd
, alb_count
);
4230 if (move_one_task(target_rq
, target_cpu
, busiest_rq
,
4232 schedstat_inc(sd
, alb_pushed
);
4234 schedstat_inc(sd
, alb_failed
);
4236 double_unlock_balance(busiest_rq
, target_rq
);
4241 atomic_t load_balancer
;
4242 cpumask_var_t cpu_mask
;
4243 } nohz ____cacheline_aligned
= {
4244 .load_balancer
= ATOMIC_INIT(-1),
4247 int get_nohz_load_balancer(void)
4249 return atomic_read(&nohz
.load_balancer
);
4253 * This routine will try to nominate the ilb (idle load balancing)
4254 * owner among the cpus whose ticks are stopped. ilb owner will do the idle
4255 * load balancing on behalf of all those cpus. If all the cpus in the system
4256 * go into this tickless mode, then there will be no ilb owner (as there is
4257 * no need for one) and all the cpus will sleep till the next wakeup event
4260 * For the ilb owner, tick is not stopped. And this tick will be used
4261 * for idle load balancing. ilb owner will still be part of
4264 * While stopping the tick, this cpu will become the ilb owner if there
4265 * is no other owner. And will be the owner till that cpu becomes busy
4266 * or if all cpus in the system stop their ticks at which point
4267 * there is no need for ilb owner.
4269 * When the ilb owner becomes busy, it nominates another owner, during the
4270 * next busy scheduler_tick()
4272 int select_nohz_load_balancer(int stop_tick
)
4274 int cpu
= smp_processor_id();
4277 cpu_rq(cpu
)->in_nohz_recently
= 1;
4279 if (!cpu_active(cpu
)) {
4280 if (atomic_read(&nohz
.load_balancer
) != cpu
)
4284 * If we are going offline and still the leader,
4287 if (atomic_cmpxchg(&nohz
.load_balancer
, cpu
, -1) != cpu
)
4293 cpumask_set_cpu(cpu
, nohz
.cpu_mask
);
4295 /* time for ilb owner also to sleep */
4296 if (cpumask_weight(nohz
.cpu_mask
) == num_online_cpus()) {
4297 if (atomic_read(&nohz
.load_balancer
) == cpu
)
4298 atomic_set(&nohz
.load_balancer
, -1);
4302 if (atomic_read(&nohz
.load_balancer
) == -1) {
4303 /* make me the ilb owner */
4304 if (atomic_cmpxchg(&nohz
.load_balancer
, -1, cpu
) == -1)
4306 } else if (atomic_read(&nohz
.load_balancer
) == cpu
)
4309 if (!cpumask_test_cpu(cpu
, nohz
.cpu_mask
))
4312 cpumask_clear_cpu(cpu
, nohz
.cpu_mask
);
4314 if (atomic_read(&nohz
.load_balancer
) == cpu
)
4315 if (atomic_cmpxchg(&nohz
.load_balancer
, cpu
, -1) != cpu
)
4322 static DEFINE_SPINLOCK(balancing
);
4325 * It checks each scheduling domain to see if it is due to be balanced,
4326 * and initiates a balancing operation if so.
4328 * Balancing parameters are set up in arch_init_sched_domains.
4330 static void rebalance_domains(int cpu
, enum cpu_idle_type idle
)
4333 struct rq
*rq
= cpu_rq(cpu
);
4334 unsigned long interval
;
4335 struct sched_domain
*sd
;
4336 /* Earliest time when we have to do rebalance again */
4337 unsigned long next_balance
= jiffies
+ 60*HZ
;
4338 int update_next_balance
= 0;
4341 for_each_domain(cpu
, sd
) {
4342 if (!(sd
->flags
& SD_LOAD_BALANCE
))
4345 interval
= sd
->balance_interval
;
4346 if (idle
!= CPU_IDLE
)
4347 interval
*= sd
->busy_factor
;
4349 /* scale ms to jiffies */
4350 interval
= msecs_to_jiffies(interval
);
4351 if (unlikely(!interval
))
4353 if (interval
> HZ
*NR_CPUS
/10)
4354 interval
= HZ
*NR_CPUS
/10;
4356 need_serialize
= sd
->flags
& SD_SERIALIZE
;
4358 if (need_serialize
) {
4359 if (!spin_trylock(&balancing
))
4363 if (time_after_eq(jiffies
, sd
->last_balance
+ interval
)) {
4364 if (load_balance(cpu
, rq
, sd
, idle
, &balance
)) {
4366 * We've pulled tasks over so either we're no
4367 * longer idle, or one of our SMT siblings is
4370 idle
= CPU_NOT_IDLE
;
4372 sd
->last_balance
= jiffies
;
4375 spin_unlock(&balancing
);
4377 if (time_after(next_balance
, sd
->last_balance
+ interval
)) {
4378 next_balance
= sd
->last_balance
+ interval
;
4379 update_next_balance
= 1;
4383 * Stop the load balance at this level. There is another
4384 * CPU in our sched group which is doing load balancing more
4392 * next_balance will be updated only when there is a need.
4393 * When the cpu is attached to null domain for ex, it will not be
4396 if (likely(update_next_balance
))
4397 rq
->next_balance
= next_balance
;
4401 * run_rebalance_domains is triggered when needed from the scheduler tick.
4402 * In CONFIG_NO_HZ case, the idle load balance owner will do the
4403 * rebalancing for all the cpus for whom scheduler ticks are stopped.
4405 static void run_rebalance_domains(struct softirq_action
*h
)
4407 int this_cpu
= smp_processor_id();
4408 struct rq
*this_rq
= cpu_rq(this_cpu
);
4409 enum cpu_idle_type idle
= this_rq
->idle_at_tick
?
4410 CPU_IDLE
: CPU_NOT_IDLE
;
4412 rebalance_domains(this_cpu
, idle
);
4416 * If this cpu is the owner for idle load balancing, then do the
4417 * balancing on behalf of the other idle cpus whose ticks are
4420 if (this_rq
->idle_at_tick
&&
4421 atomic_read(&nohz
.load_balancer
) == this_cpu
) {
4425 for_each_cpu(balance_cpu
, nohz
.cpu_mask
) {
4426 if (balance_cpu
== this_cpu
)
4430 * If this cpu gets work to do, stop the load balancing
4431 * work being done for other cpus. Next load
4432 * balancing owner will pick it up.
4437 rebalance_domains(balance_cpu
, CPU_IDLE
);
4439 rq
= cpu_rq(balance_cpu
);
4440 if (time_after(this_rq
->next_balance
, rq
->next_balance
))
4441 this_rq
->next_balance
= rq
->next_balance
;
4447 static inline int on_null_domain(int cpu
)
4449 return !rcu_dereference(cpu_rq(cpu
)->sd
);
4453 * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing.
4455 * In case of CONFIG_NO_HZ, this is the place where we nominate a new
4456 * idle load balancing owner or decide to stop the periodic load balancing,
4457 * if the whole system is idle.
4459 static inline void trigger_load_balance(struct rq
*rq
, int cpu
)
4463 * If we were in the nohz mode recently and busy at the current
4464 * scheduler tick, then check if we need to nominate new idle
4467 if (rq
->in_nohz_recently
&& !rq
->idle_at_tick
) {
4468 rq
->in_nohz_recently
= 0;
4470 if (atomic_read(&nohz
.load_balancer
) == cpu
) {
4471 cpumask_clear_cpu(cpu
, nohz
.cpu_mask
);
4472 atomic_set(&nohz
.load_balancer
, -1);
4475 if (atomic_read(&nohz
.load_balancer
) == -1) {
4477 * simple selection for now: Nominate the
4478 * first cpu in the nohz list to be the next
4481 * TBD: Traverse the sched domains and nominate
4482 * the nearest cpu in the nohz.cpu_mask.
4484 int ilb
= cpumask_first(nohz
.cpu_mask
);
4486 if (ilb
< nr_cpu_ids
)
4492 * If this cpu is idle and doing idle load balancing for all the
4493 * cpus with ticks stopped, is it time for that to stop?
4495 if (rq
->idle_at_tick
&& atomic_read(&nohz
.load_balancer
) == cpu
&&
4496 cpumask_weight(nohz
.cpu_mask
) == num_online_cpus()) {
4502 * If this cpu is idle and the idle load balancing is done by
4503 * someone else, then no need raise the SCHED_SOFTIRQ
4505 if (rq
->idle_at_tick
&& atomic_read(&nohz
.load_balancer
) != cpu
&&
4506 cpumask_test_cpu(cpu
, nohz
.cpu_mask
))
4509 /* Don't need to rebalance while attached to NULL domain */
4510 if (time_after_eq(jiffies
, rq
->next_balance
) &&
4511 likely(!on_null_domain(cpu
)))
4512 raise_softirq(SCHED_SOFTIRQ
);
4515 #else /* CONFIG_SMP */
4518 * on UP we do not need to balance between CPUs:
4520 static inline void idle_balance(int cpu
, struct rq
*rq
)
4526 DEFINE_PER_CPU(struct kernel_stat
, kstat
);
4528 EXPORT_PER_CPU_SYMBOL(kstat
);
4531 * Return any ns on the sched_clock that have not yet been accounted in
4532 * @p in case that task is currently running.
4534 * Called with task_rq_lock() held on @rq.
4536 static u64
do_task_delta_exec(struct task_struct
*p
, struct rq
*rq
)
4540 if (task_current(rq
, p
)) {
4541 update_rq_clock(rq
);
4542 ns
= rq
->clock
- p
->se
.exec_start
;
4550 unsigned long long task_delta_exec(struct task_struct
*p
)
4552 unsigned long flags
;
4556 rq
= task_rq_lock(p
, &flags
);
4557 ns
= do_task_delta_exec(p
, rq
);
4558 task_rq_unlock(rq
, &flags
);
4564 * Return accounted runtime for the task.
4565 * In case the task is currently running, return the runtime plus current's
4566 * pending runtime that have not been accounted yet.
4568 unsigned long long task_sched_runtime(struct task_struct
*p
)
4570 unsigned long flags
;
4574 rq
= task_rq_lock(p
, &flags
);
4575 ns
= p
->se
.sum_exec_runtime
+ do_task_delta_exec(p
, rq
);
4576 task_rq_unlock(rq
, &flags
);
4582 * Return sum_exec_runtime for the thread group.
4583 * In case the task is currently running, return the sum plus current's
4584 * pending runtime that have not been accounted yet.
4586 * Note that the thread group might have other running tasks as well,
4587 * so the return value not includes other pending runtime that other
4588 * running tasks might have.
4590 unsigned long long thread_group_sched_runtime(struct task_struct
*p
)
4592 struct task_cputime totals
;
4593 unsigned long flags
;
4597 rq
= task_rq_lock(p
, &flags
);
4598 thread_group_cputime(p
, &totals
);
4599 ns
= totals
.sum_exec_runtime
+ do_task_delta_exec(p
, rq
);
4600 task_rq_unlock(rq
, &flags
);
4606 * Account user cpu time to a process.
4607 * @p: the process that the cpu time gets accounted to
4608 * @cputime: the cpu time spent in user space since the last update
4609 * @cputime_scaled: cputime scaled by cpu frequency
4611 void account_user_time(struct task_struct
*p
, cputime_t cputime
,
4612 cputime_t cputime_scaled
)
4614 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
4617 /* Add user time to process. */
4618 p
->utime
= cputime_add(p
->utime
, cputime
);
4619 p
->utimescaled
= cputime_add(p
->utimescaled
, cputime_scaled
);
4620 account_group_user_time(p
, cputime
);
4622 /* Add user time to cpustat. */
4623 tmp
= cputime_to_cputime64(cputime
);
4624 if (TASK_NICE(p
) > 0)
4625 cpustat
->nice
= cputime64_add(cpustat
->nice
, tmp
);
4627 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
4629 cpuacct_update_stats(p
, CPUACCT_STAT_USER
, cputime
);
4630 /* Account for user time used */
4631 acct_update_integrals(p
);
4635 * Account guest cpu time to a process.
4636 * @p: the process that the cpu time gets accounted to
4637 * @cputime: the cpu time spent in virtual machine since the last update
4638 * @cputime_scaled: cputime scaled by cpu frequency
4640 static void account_guest_time(struct task_struct
*p
, cputime_t cputime
,
4641 cputime_t cputime_scaled
)
4644 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
4646 tmp
= cputime_to_cputime64(cputime
);
4648 /* Add guest time to process. */
4649 p
->utime
= cputime_add(p
->utime
, cputime
);
4650 p
->utimescaled
= cputime_add(p
->utimescaled
, cputime_scaled
);
4651 account_group_user_time(p
, cputime
);
4652 p
->gtime
= cputime_add(p
->gtime
, cputime
);
4654 /* Add guest time to cpustat. */
4655 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
4656 cpustat
->guest
= cputime64_add(cpustat
->guest
, tmp
);
4660 * Account system cpu time to a process.
4661 * @p: the process that the cpu time gets accounted to
4662 * @hardirq_offset: the offset to subtract from hardirq_count()
4663 * @cputime: the cpu time spent in kernel space since the last update
4664 * @cputime_scaled: cputime scaled by cpu frequency
4666 void account_system_time(struct task_struct
*p
, int hardirq_offset
,
4667 cputime_t cputime
, cputime_t cputime_scaled
)
4669 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
4672 if ((p
->flags
& PF_VCPU
) && (irq_count() - hardirq_offset
== 0)) {
4673 account_guest_time(p
, cputime
, cputime_scaled
);
4677 /* Add system time to process. */
4678 p
->stime
= cputime_add(p
->stime
, cputime
);
4679 p
->stimescaled
= cputime_add(p
->stimescaled
, cputime_scaled
);
4680 account_group_system_time(p
, cputime
);
4682 /* Add system time to cpustat. */
4683 tmp
= cputime_to_cputime64(cputime
);
4684 if (hardirq_count() - hardirq_offset
)
4685 cpustat
->irq
= cputime64_add(cpustat
->irq
, tmp
);
4686 else if (softirq_count())
4687 cpustat
->softirq
= cputime64_add(cpustat
->softirq
, tmp
);
4689 cpustat
->system
= cputime64_add(cpustat
->system
, tmp
);
4691 cpuacct_update_stats(p
, CPUACCT_STAT_SYSTEM
, cputime
);
4693 /* Account for system time used */
4694 acct_update_integrals(p
);
4698 * Account for involuntary wait time.
4699 * @steal: the cpu time spent in involuntary wait
4701 void account_steal_time(cputime_t cputime
)
4703 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
4704 cputime64_t cputime64
= cputime_to_cputime64(cputime
);
4706 cpustat
->steal
= cputime64_add(cpustat
->steal
, cputime64
);
4710 * Account for idle time.
4711 * @cputime: the cpu time spent in idle wait
4713 void account_idle_time(cputime_t cputime
)
4715 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
4716 cputime64_t cputime64
= cputime_to_cputime64(cputime
);
4717 struct rq
*rq
= this_rq();
4719 if (atomic_read(&rq
->nr_iowait
) > 0)
4720 cpustat
->iowait
= cputime64_add(cpustat
->iowait
, cputime64
);
4722 cpustat
->idle
= cputime64_add(cpustat
->idle
, cputime64
);
4725 #ifndef CONFIG_VIRT_CPU_ACCOUNTING
4728 * Account a single tick of cpu time.
4729 * @p: the process that the cpu time gets accounted to
4730 * @user_tick: indicates if the tick is a user or a system tick
4732 void account_process_tick(struct task_struct
*p
, int user_tick
)
4734 cputime_t one_jiffy
= jiffies_to_cputime(1);
4735 cputime_t one_jiffy_scaled
= cputime_to_scaled(one_jiffy
);
4736 struct rq
*rq
= this_rq();
4739 account_user_time(p
, one_jiffy
, one_jiffy_scaled
);
4740 else if (p
!= rq
->idle
)
4741 account_system_time(p
, HARDIRQ_OFFSET
, one_jiffy
,
4744 account_idle_time(one_jiffy
);
4748 * Account multiple ticks of steal time.
4749 * @p: the process from which the cpu time has been stolen
4750 * @ticks: number of stolen ticks
4752 void account_steal_ticks(unsigned long ticks
)
4754 account_steal_time(jiffies_to_cputime(ticks
));
4758 * Account multiple ticks of idle time.
4759 * @ticks: number of stolen ticks
4761 void account_idle_ticks(unsigned long ticks
)
4763 account_idle_time(jiffies_to_cputime(ticks
));
4769 * Use precise platform statistics if available:
4771 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
4772 cputime_t
task_utime(struct task_struct
*p
)
4777 cputime_t
task_stime(struct task_struct
*p
)
4782 cputime_t
task_utime(struct task_struct
*p
)
4784 clock_t utime
= cputime_to_clock_t(p
->utime
),
4785 total
= utime
+ cputime_to_clock_t(p
->stime
);
4789 * Use CFS's precise accounting:
4791 temp
= (u64
)nsec_to_clock_t(p
->se
.sum_exec_runtime
);
4795 do_div(temp
, total
);
4797 utime
= (clock_t)temp
;
4799 p
->prev_utime
= max(p
->prev_utime
, clock_t_to_cputime(utime
));
4800 return p
->prev_utime
;
4803 cputime_t
task_stime(struct task_struct
*p
)
4808 * Use CFS's precise accounting. (we subtract utime from
4809 * the total, to make sure the total observed by userspace
4810 * grows monotonically - apps rely on that):
4812 stime
= nsec_to_clock_t(p
->se
.sum_exec_runtime
) -
4813 cputime_to_clock_t(task_utime(p
));
4816 p
->prev_stime
= max(p
->prev_stime
, clock_t_to_cputime(stime
));
4818 return p
->prev_stime
;
4822 inline cputime_t
task_gtime(struct task_struct
*p
)
4828 * This function gets called by the timer code, with HZ frequency.
4829 * We call it with interrupts disabled.
4831 * It also gets called by the fork code, when changing the parent's
4834 void scheduler_tick(void)
4836 int cpu
= smp_processor_id();
4837 struct rq
*rq
= cpu_rq(cpu
);
4838 struct task_struct
*curr
= rq
->curr
;
4842 spin_lock(&rq
->lock
);
4843 update_rq_clock(rq
);
4844 update_cpu_load(rq
);
4845 curr
->sched_class
->task_tick(rq
, curr
, 0);
4846 spin_unlock(&rq
->lock
);
4849 rq
->idle_at_tick
= idle_cpu(cpu
);
4850 trigger_load_balance(rq
, cpu
);
4854 notrace
unsigned long get_parent_ip(unsigned long addr
)
4856 if (in_lock_functions(addr
)) {
4857 addr
= CALLER_ADDR2
;
4858 if (in_lock_functions(addr
))
4859 addr
= CALLER_ADDR3
;
4864 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
4865 defined(CONFIG_PREEMPT_TRACER))
4867 void __kprobes
add_preempt_count(int val
)
4869 #ifdef CONFIG_DEBUG_PREEMPT
4873 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
4876 preempt_count() += val
;
4877 #ifdef CONFIG_DEBUG_PREEMPT
4879 * Spinlock count overflowing soon?
4881 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK
) >=
4884 if (preempt_count() == val
)
4885 trace_preempt_off(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
4887 EXPORT_SYMBOL(add_preempt_count
);
4889 void __kprobes
sub_preempt_count(int val
)
4891 #ifdef CONFIG_DEBUG_PREEMPT
4895 if (DEBUG_LOCKS_WARN_ON(val
> preempt_count()))
4898 * Is the spinlock portion underflowing?
4900 if (DEBUG_LOCKS_WARN_ON((val
< PREEMPT_MASK
) &&
4901 !(preempt_count() & PREEMPT_MASK
)))
4905 if (preempt_count() == val
)
4906 trace_preempt_on(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
4907 preempt_count() -= val
;
4909 EXPORT_SYMBOL(sub_preempt_count
);
4914 * Print scheduling while atomic bug:
4916 static noinline
void __schedule_bug(struct task_struct
*prev
)
4918 struct pt_regs
*regs
= get_irq_regs();
4920 printk(KERN_ERR
"BUG: scheduling while atomic: %s/%d/0x%08x\n",
4921 prev
->comm
, prev
->pid
, preempt_count());
4923 debug_show_held_locks(prev
);
4925 if (irqs_disabled())
4926 print_irqtrace_events(prev
);
4935 * Various schedule()-time debugging checks and statistics:
4937 static inline void schedule_debug(struct task_struct
*prev
)
4940 * Test if we are atomic. Since do_exit() needs to call into
4941 * schedule() atomically, we ignore that path for now.
4942 * Otherwise, whine if we are scheduling when we should not be.
4944 if (unlikely(in_atomic_preempt_off() && !prev
->exit_state
))
4945 __schedule_bug(prev
);
4947 profile_hit(SCHED_PROFILING
, __builtin_return_address(0));
4949 schedstat_inc(this_rq(), sched_count
);
4950 #ifdef CONFIG_SCHEDSTATS
4951 if (unlikely(prev
->lock_depth
>= 0)) {
4952 schedstat_inc(this_rq(), bkl_count
);
4953 schedstat_inc(prev
, sched_info
.bkl_count
);
4958 static void put_prev_task(struct rq
*rq
, struct task_struct
*prev
)
4960 if (prev
->state
== TASK_RUNNING
) {
4961 u64 runtime
= prev
->se
.sum_exec_runtime
;
4963 runtime
-= prev
->se
.prev_sum_exec_runtime
;
4964 runtime
= min_t(u64
, runtime
, 2*sysctl_sched_migration_cost
);
4967 * In order to avoid avg_overlap growing stale when we are
4968 * indeed overlapping and hence not getting put to sleep, grow
4969 * the avg_overlap on preemption.
4971 * We use the average preemption runtime because that
4972 * correlates to the amount of cache footprint a task can
4975 update_avg(&prev
->se
.avg_overlap
, runtime
);
4977 prev
->sched_class
->put_prev_task(rq
, prev
);
4981 * Pick up the highest-prio task:
4983 static inline struct task_struct
*
4984 pick_next_task(struct rq
*rq
)
4986 const struct sched_class
*class;
4987 struct task_struct
*p
;
4990 * Optimization: we know that if all tasks are in
4991 * the fair class we can call that function directly:
4993 if (likely(rq
->nr_running
== rq
->cfs
.nr_running
)) {
4994 p
= fair_sched_class
.pick_next_task(rq
);
4999 class = sched_class_highest
;
5001 p
= class->pick_next_task(rq
);
5005 * Will never be NULL as the idle class always
5006 * returns a non-NULL p:
5008 class = class->next
;
5013 * schedule() is the main scheduler function.
5015 asmlinkage
void __sched
__schedule(void)
5017 struct task_struct
*prev
, *next
;
5018 unsigned long *switch_count
;
5022 cpu
= smp_processor_id();
5026 switch_count
= &prev
->nivcsw
;
5028 release_kernel_lock(prev
);
5029 need_resched_nonpreemptible
:
5031 schedule_debug(prev
);
5033 if (sched_feat(HRTICK
))
5036 spin_lock_irq(&rq
->lock
);
5037 update_rq_clock(rq
);
5038 clear_tsk_need_resched(prev
);
5040 if (prev
->state
&& !(preempt_count() & PREEMPT_ACTIVE
)) {
5041 if (unlikely(signal_pending_state(prev
->state
, prev
)))
5042 prev
->state
= TASK_RUNNING
;
5044 deactivate_task(rq
, prev
, 1);
5045 switch_count
= &prev
->nvcsw
;
5049 if (prev
->sched_class
->pre_schedule
)
5050 prev
->sched_class
->pre_schedule(rq
, prev
);
5053 if (unlikely(!rq
->nr_running
))
5054 idle_balance(cpu
, rq
);
5056 put_prev_task(rq
, prev
);
5057 next
= pick_next_task(rq
);
5059 if (likely(prev
!= next
)) {
5060 sched_info_switch(prev
, next
);
5066 context_switch(rq
, prev
, next
); /* unlocks the rq */
5068 * the context switch might have flipped the stack from under
5069 * us, hence refresh the local variables.
5071 cpu
= smp_processor_id();
5074 spin_unlock_irq(&rq
->lock
);
5076 if (unlikely(reacquire_kernel_lock(current
) < 0))
5077 goto need_resched_nonpreemptible
;
5080 asmlinkage
void __sched
schedule(void)
5085 preempt_enable_no_resched();
5086 if (unlikely(test_thread_flag(TIF_NEED_RESCHED
)))
5089 EXPORT_SYMBOL(schedule
);
5093 * Look out! "owner" is an entirely speculative pointer
5094 * access and not reliable.
5096 int mutex_spin_on_owner(struct mutex
*lock
, struct thread_info
*owner
)
5101 if (!sched_feat(OWNER_SPIN
))
5104 #ifdef CONFIG_DEBUG_PAGEALLOC
5106 * Need to access the cpu field knowing that
5107 * DEBUG_PAGEALLOC could have unmapped it if
5108 * the mutex owner just released it and exited.
5110 if (probe_kernel_address(&owner
->cpu
, cpu
))
5117 * Even if the access succeeded (likely case),
5118 * the cpu field may no longer be valid.
5120 if (cpu
>= nr_cpumask_bits
)
5124 * We need to validate that we can do a
5125 * get_cpu() and that we have the percpu area.
5127 if (!cpu_online(cpu
))
5134 * Owner changed, break to re-assess state.
5136 if (lock
->owner
!= owner
)
5140 * Is that owner really running on that cpu?
5142 if (task_thread_info(rq
->curr
) != owner
|| need_resched())
5152 #ifdef CONFIG_PREEMPT
5154 * this is the entry point to schedule() from in-kernel preemption
5155 * off of preempt_enable. Kernel preemptions off return from interrupt
5156 * occur there and call schedule directly.
5158 asmlinkage
void __sched
preempt_schedule(void)
5160 struct thread_info
*ti
= current_thread_info();
5163 * If there is a non-zero preempt_count or interrupts are disabled,
5164 * we do not want to preempt the current task. Just return..
5166 if (likely(ti
->preempt_count
|| irqs_disabled()))
5170 add_preempt_count(PREEMPT_ACTIVE
);
5172 sub_preempt_count(PREEMPT_ACTIVE
);
5175 * Check again in case we missed a preemption opportunity
5176 * between schedule and now.
5179 } while (need_resched());
5181 EXPORT_SYMBOL(preempt_schedule
);
5184 * this is the entry point to schedule() from kernel preemption
5185 * off of irq context.
5186 * Note, that this is called and return with irqs disabled. This will
5187 * protect us against recursive calling from irq.
5189 asmlinkage
void __sched
preempt_schedule_irq(void)
5191 struct thread_info
*ti
= current_thread_info();
5193 /* Catch callers which need to be fixed */
5194 BUG_ON(ti
->preempt_count
|| !irqs_disabled());
5197 add_preempt_count(PREEMPT_ACTIVE
);
5200 local_irq_disable();
5201 sub_preempt_count(PREEMPT_ACTIVE
);
5204 * Check again in case we missed a preemption opportunity
5205 * between schedule and now.
5208 } while (need_resched());
5211 #endif /* CONFIG_PREEMPT */
5213 int default_wake_function(wait_queue_t
*curr
, unsigned mode
, int sync
,
5216 return try_to_wake_up(curr
->private, mode
, sync
);
5218 EXPORT_SYMBOL(default_wake_function
);
5221 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
5222 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
5223 * number) then we wake all the non-exclusive tasks and one exclusive task.
5225 * There are circumstances in which we can try to wake a task which has already
5226 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
5227 * zero in this (rare) case, and we handle it by continuing to scan the queue.
5229 void __wake_up_common(wait_queue_head_t
*q
, unsigned int mode
,
5230 int nr_exclusive
, int sync
, void *key
)
5232 wait_queue_t
*curr
, *next
;
5234 list_for_each_entry_safe(curr
, next
, &q
->task_list
, task_list
) {
5235 unsigned flags
= curr
->flags
;
5237 if (curr
->func(curr
, mode
, sync
, key
) &&
5238 (flags
& WQ_FLAG_EXCLUSIVE
) && !--nr_exclusive
)
5244 * __wake_up - wake up threads blocked on a waitqueue.
5246 * @mode: which threads
5247 * @nr_exclusive: how many wake-one or wake-many threads to wake up
5248 * @key: is directly passed to the wakeup function
5250 void __wake_up(wait_queue_head_t
*q
, unsigned int mode
,
5251 int nr_exclusive
, void *key
)
5253 unsigned long flags
;
5255 spin_lock_irqsave(&q
->lock
, flags
);
5256 __wake_up_common(q
, mode
, nr_exclusive
, 0, key
);
5257 spin_unlock_irqrestore(&q
->lock
, flags
);
5259 EXPORT_SYMBOL(__wake_up
);
5262 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
5264 void __wake_up_locked(wait_queue_head_t
*q
, unsigned int mode
)
5266 __wake_up_common(q
, mode
, 1, 0, NULL
);
5269 void __wake_up_locked_key(wait_queue_head_t
*q
, unsigned int mode
, void *key
)
5271 __wake_up_common(q
, mode
, 1, 0, key
);
5275 * __wake_up_sync_key - wake up threads blocked on a waitqueue.
5277 * @mode: which threads
5278 * @nr_exclusive: how many wake-one or wake-many threads to wake up
5279 * @key: opaque value to be passed to wakeup targets
5281 * The sync wakeup differs that the waker knows that it will schedule
5282 * away soon, so while the target thread will be woken up, it will not
5283 * be migrated to another CPU - ie. the two threads are 'synchronized'
5284 * with each other. This can prevent needless bouncing between CPUs.
5286 * On UP it can prevent extra preemption.
5288 void __wake_up_sync_key(wait_queue_head_t
*q
, unsigned int mode
,
5289 int nr_exclusive
, void *key
)
5291 unsigned long flags
;
5297 if (unlikely(!nr_exclusive
))
5300 spin_lock_irqsave(&q
->lock
, flags
);
5301 __wake_up_common(q
, mode
, nr_exclusive
, sync
, key
);
5302 spin_unlock_irqrestore(&q
->lock
, flags
);
5304 EXPORT_SYMBOL_GPL(__wake_up_sync_key
);
5307 * __wake_up_sync - see __wake_up_sync_key()
5309 void __wake_up_sync(wait_queue_head_t
*q
, unsigned int mode
, int nr_exclusive
)
5311 __wake_up_sync_key(q
, mode
, nr_exclusive
, NULL
);
5313 EXPORT_SYMBOL_GPL(__wake_up_sync
); /* For internal use only */
5316 * complete: - signals a single thread waiting on this completion
5317 * @x: holds the state of this particular completion
5319 * This will wake up a single thread waiting on this completion. Threads will be
5320 * awakened in the same order in which they were queued.
5322 * See also complete_all(), wait_for_completion() and related routines.
5324 void complete(struct completion
*x
)
5326 unsigned long flags
;
5328 spin_lock_irqsave(&x
->wait
.lock
, flags
);
5330 __wake_up_common(&x
->wait
, TASK_NORMAL
, 1, 0, NULL
);
5331 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
5333 EXPORT_SYMBOL(complete
);
5336 * complete_all: - signals all threads waiting on this completion
5337 * @x: holds the state of this particular completion
5339 * This will wake up all threads waiting on this particular completion event.
5341 void complete_all(struct completion
*x
)
5343 unsigned long flags
;
5345 spin_lock_irqsave(&x
->wait
.lock
, flags
);
5346 x
->done
+= UINT_MAX
/2;
5347 __wake_up_common(&x
->wait
, TASK_NORMAL
, 0, 0, NULL
);
5348 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
5350 EXPORT_SYMBOL(complete_all
);
5352 static inline long __sched
5353 do_wait_for_common(struct completion
*x
, long timeout
, int state
)
5356 DECLARE_WAITQUEUE(wait
, current
);
5358 wait
.flags
|= WQ_FLAG_EXCLUSIVE
;
5359 __add_wait_queue_tail(&x
->wait
, &wait
);
5361 if (signal_pending_state(state
, current
)) {
5362 timeout
= -ERESTARTSYS
;
5365 __set_current_state(state
);
5366 spin_unlock_irq(&x
->wait
.lock
);
5367 timeout
= schedule_timeout(timeout
);
5368 spin_lock_irq(&x
->wait
.lock
);
5369 } while (!x
->done
&& timeout
);
5370 __remove_wait_queue(&x
->wait
, &wait
);
5375 return timeout
?: 1;
5379 wait_for_common(struct completion
*x
, long timeout
, int state
)
5383 spin_lock_irq(&x
->wait
.lock
);
5384 timeout
= do_wait_for_common(x
, timeout
, state
);
5385 spin_unlock_irq(&x
->wait
.lock
);
5390 * wait_for_completion: - waits for completion of a task
5391 * @x: holds the state of this particular completion
5393 * This waits to be signaled for completion of a specific task. It is NOT
5394 * interruptible and there is no timeout.
5396 * See also similar routines (i.e. wait_for_completion_timeout()) with timeout
5397 * and interrupt capability. Also see complete().
5399 void __sched
wait_for_completion(struct completion
*x
)
5401 wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_UNINTERRUPTIBLE
);
5403 EXPORT_SYMBOL(wait_for_completion
);
5406 * wait_for_completion_timeout: - waits for completion of a task (w/timeout)
5407 * @x: holds the state of this particular completion
5408 * @timeout: timeout value in jiffies
5410 * This waits for either a completion of a specific task to be signaled or for a
5411 * specified timeout to expire. The timeout is in jiffies. It is not
5414 unsigned long __sched
5415 wait_for_completion_timeout(struct completion
*x
, unsigned long timeout
)
5417 return wait_for_common(x
, timeout
, TASK_UNINTERRUPTIBLE
);
5419 EXPORT_SYMBOL(wait_for_completion_timeout
);
5422 * wait_for_completion_interruptible: - waits for completion of a task (w/intr)
5423 * @x: holds the state of this particular completion
5425 * This waits for completion of a specific task to be signaled. It is
5428 int __sched
wait_for_completion_interruptible(struct completion
*x
)
5430 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_INTERRUPTIBLE
);
5431 if (t
== -ERESTARTSYS
)
5435 EXPORT_SYMBOL(wait_for_completion_interruptible
);
5438 * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr))
5439 * @x: holds the state of this particular completion
5440 * @timeout: timeout value in jiffies
5442 * This waits for either a completion of a specific task to be signaled or for a
5443 * specified timeout to expire. It is interruptible. The timeout is in jiffies.
5445 unsigned long __sched
5446 wait_for_completion_interruptible_timeout(struct completion
*x
,
5447 unsigned long timeout
)
5449 return wait_for_common(x
, timeout
, TASK_INTERRUPTIBLE
);
5451 EXPORT_SYMBOL(wait_for_completion_interruptible_timeout
);
5454 * wait_for_completion_killable: - waits for completion of a task (killable)
5455 * @x: holds the state of this particular completion
5457 * This waits to be signaled for completion of a specific task. It can be
5458 * interrupted by a kill signal.
5460 int __sched
wait_for_completion_killable(struct completion
*x
)
5462 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_KILLABLE
);
5463 if (t
== -ERESTARTSYS
)
5467 EXPORT_SYMBOL(wait_for_completion_killable
);
5470 * try_wait_for_completion - try to decrement a completion without blocking
5471 * @x: completion structure
5473 * Returns: 0 if a decrement cannot be done without blocking
5474 * 1 if a decrement succeeded.
5476 * If a completion is being used as a counting completion,
5477 * attempt to decrement the counter without blocking. This
5478 * enables us to avoid waiting if the resource the completion
5479 * is protecting is not available.
5481 bool try_wait_for_completion(struct completion
*x
)
5485 spin_lock_irq(&x
->wait
.lock
);
5490 spin_unlock_irq(&x
->wait
.lock
);
5493 EXPORT_SYMBOL(try_wait_for_completion
);
5496 * completion_done - Test to see if a completion has any waiters
5497 * @x: completion structure
5499 * Returns: 0 if there are waiters (wait_for_completion() in progress)
5500 * 1 if there are no waiters.
5503 bool completion_done(struct completion
*x
)
5507 spin_lock_irq(&x
->wait
.lock
);
5510 spin_unlock_irq(&x
->wait
.lock
);
5513 EXPORT_SYMBOL(completion_done
);
5516 sleep_on_common(wait_queue_head_t
*q
, int state
, long timeout
)
5518 unsigned long flags
;
5521 init_waitqueue_entry(&wait
, current
);
5523 __set_current_state(state
);
5525 spin_lock_irqsave(&q
->lock
, flags
);
5526 __add_wait_queue(q
, &wait
);
5527 spin_unlock(&q
->lock
);
5528 timeout
= schedule_timeout(timeout
);
5529 spin_lock_irq(&q
->lock
);
5530 __remove_wait_queue(q
, &wait
);
5531 spin_unlock_irqrestore(&q
->lock
, flags
);
5536 void __sched
interruptible_sleep_on(wait_queue_head_t
*q
)
5538 sleep_on_common(q
, TASK_INTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
5540 EXPORT_SYMBOL(interruptible_sleep_on
);
5543 interruptible_sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
5545 return sleep_on_common(q
, TASK_INTERRUPTIBLE
, timeout
);
5547 EXPORT_SYMBOL(interruptible_sleep_on_timeout
);
5549 void __sched
sleep_on(wait_queue_head_t
*q
)
5551 sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
5553 EXPORT_SYMBOL(sleep_on
);
5555 long __sched
sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
5557 return sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, timeout
);
5559 EXPORT_SYMBOL(sleep_on_timeout
);
5561 #ifdef CONFIG_RT_MUTEXES
5564 * rt_mutex_setprio - set the current priority of a task
5566 * @prio: prio value (kernel-internal form)
5568 * This function changes the 'effective' priority of a task. It does
5569 * not touch ->normal_prio like __setscheduler().
5571 * Used by the rt_mutex code to implement priority inheritance logic.
5573 void rt_mutex_setprio(struct task_struct
*p
, int prio
)
5575 unsigned long flags
;
5576 int oldprio
, on_rq
, running
;
5578 const struct sched_class
*prev_class
= p
->sched_class
;
5580 BUG_ON(prio
< 0 || prio
> MAX_PRIO
);
5582 rq
= task_rq_lock(p
, &flags
);
5583 update_rq_clock(rq
);
5586 on_rq
= p
->se
.on_rq
;
5587 running
= task_current(rq
, p
);
5589 dequeue_task(rq
, p
, 0);
5591 p
->sched_class
->put_prev_task(rq
, p
);
5594 p
->sched_class
= &rt_sched_class
;
5596 p
->sched_class
= &fair_sched_class
;
5601 p
->sched_class
->set_curr_task(rq
);
5603 enqueue_task(rq
, p
, 0);
5605 check_class_changed(rq
, p
, prev_class
, oldprio
, running
);
5607 task_rq_unlock(rq
, &flags
);
5612 void set_user_nice(struct task_struct
*p
, long nice
)
5614 int old_prio
, delta
, on_rq
;
5615 unsigned long flags
;
5618 if (TASK_NICE(p
) == nice
|| nice
< -20 || nice
> 19)
5621 * We have to be careful, if called from sys_setpriority(),
5622 * the task might be in the middle of scheduling on another CPU.
5624 rq
= task_rq_lock(p
, &flags
);
5625 update_rq_clock(rq
);
5627 * The RT priorities are set via sched_setscheduler(), but we still
5628 * allow the 'normal' nice value to be set - but as expected
5629 * it wont have any effect on scheduling until the task is
5630 * SCHED_FIFO/SCHED_RR:
5632 if (task_has_rt_policy(p
)) {
5633 p
->static_prio
= NICE_TO_PRIO(nice
);
5636 on_rq
= p
->se
.on_rq
;
5638 dequeue_task(rq
, p
, 0);
5640 p
->static_prio
= NICE_TO_PRIO(nice
);
5643 p
->prio
= effective_prio(p
);
5644 delta
= p
->prio
- old_prio
;
5647 enqueue_task(rq
, p
, 0);
5649 * If the task increased its priority or is running and
5650 * lowered its priority, then reschedule its CPU:
5652 if (delta
< 0 || (delta
> 0 && task_running(rq
, p
)))
5653 resched_task(rq
->curr
);
5656 task_rq_unlock(rq
, &flags
);
5658 EXPORT_SYMBOL(set_user_nice
);
5661 * can_nice - check if a task can reduce its nice value
5665 int can_nice(const struct task_struct
*p
, const int nice
)
5667 /* convert nice value [19,-20] to rlimit style value [1,40] */
5668 int nice_rlim
= 20 - nice
;
5670 return (nice_rlim
<= p
->signal
->rlim
[RLIMIT_NICE
].rlim_cur
||
5671 capable(CAP_SYS_NICE
));
5674 #ifdef __ARCH_WANT_SYS_NICE
5677 * sys_nice - change the priority of the current process.
5678 * @increment: priority increment
5680 * sys_setpriority is a more generic, but much slower function that
5681 * does similar things.
5683 SYSCALL_DEFINE1(nice
, int, increment
)
5688 * Setpriority might change our priority at the same moment.
5689 * We don't have to worry. Conceptually one call occurs first
5690 * and we have a single winner.
5692 if (increment
< -40)
5697 nice
= TASK_NICE(current
) + increment
;
5703 if (increment
< 0 && !can_nice(current
, nice
))
5706 retval
= security_task_setnice(current
, nice
);
5710 set_user_nice(current
, nice
);
5717 * task_prio - return the priority value of a given task.
5718 * @p: the task in question.
5720 * This is the priority value as seen by users in /proc.
5721 * RT tasks are offset by -200. Normal tasks are centered
5722 * around 0, value goes from -16 to +15.
5724 int task_prio(const struct task_struct
*p
)
5726 return p
->prio
- MAX_RT_PRIO
;
5730 * task_nice - return the nice value of a given task.
5731 * @p: the task in question.
5733 int task_nice(const struct task_struct
*p
)
5735 return TASK_NICE(p
);
5737 EXPORT_SYMBOL(task_nice
);
5740 * idle_cpu - is a given cpu idle currently?
5741 * @cpu: the processor in question.
5743 int idle_cpu(int cpu
)
5745 return cpu_curr(cpu
) == cpu_rq(cpu
)->idle
;
5749 * idle_task - return the idle task for a given cpu.
5750 * @cpu: the processor in question.
5752 struct task_struct
*idle_task(int cpu
)
5754 return cpu_rq(cpu
)->idle
;
5758 * find_process_by_pid - find a process with a matching PID value.
5759 * @pid: the pid in question.
5761 static struct task_struct
*find_process_by_pid(pid_t pid
)
5763 return pid
? find_task_by_vpid(pid
) : current
;
5766 /* Actually do priority change: must hold rq lock. */
5768 __setscheduler(struct rq
*rq
, struct task_struct
*p
, int policy
, int prio
)
5770 BUG_ON(p
->se
.on_rq
);
5773 switch (p
->policy
) {
5777 p
->sched_class
= &fair_sched_class
;
5781 p
->sched_class
= &rt_sched_class
;
5785 p
->rt_priority
= prio
;
5786 p
->normal_prio
= normal_prio(p
);
5787 /* we are holding p->pi_lock already */
5788 p
->prio
= rt_mutex_getprio(p
);
5793 * check the target process has a UID that matches the current process's
5795 static bool check_same_owner(struct task_struct
*p
)
5797 const struct cred
*cred
= current_cred(), *pcred
;
5801 pcred
= __task_cred(p
);
5802 match
= (cred
->euid
== pcred
->euid
||
5803 cred
->euid
== pcred
->uid
);
5808 static int __sched_setscheduler(struct task_struct
*p
, int policy
,
5809 struct sched_param
*param
, bool user
)
5811 int retval
, oldprio
, oldpolicy
= -1, on_rq
, running
;
5812 unsigned long flags
;
5813 const struct sched_class
*prev_class
= p
->sched_class
;
5816 /* may grab non-irq protected spin_locks */
5817 BUG_ON(in_interrupt());
5819 /* double check policy once rq lock held */
5821 policy
= oldpolicy
= p
->policy
;
5822 else if (policy
!= SCHED_FIFO
&& policy
!= SCHED_RR
&&
5823 policy
!= SCHED_NORMAL
&& policy
!= SCHED_BATCH
&&
5824 policy
!= SCHED_IDLE
)
5827 * Valid priorities for SCHED_FIFO and SCHED_RR are
5828 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
5829 * SCHED_BATCH and SCHED_IDLE is 0.
5831 if (param
->sched_priority
< 0 ||
5832 (p
->mm
&& param
->sched_priority
> MAX_USER_RT_PRIO
-1) ||
5833 (!p
->mm
&& param
->sched_priority
> MAX_RT_PRIO
-1))
5835 if (rt_policy(policy
) != (param
->sched_priority
!= 0))
5839 * Allow unprivileged RT tasks to decrease priority:
5841 if (user
&& !capable(CAP_SYS_NICE
)) {
5842 if (rt_policy(policy
)) {
5843 unsigned long rlim_rtprio
;
5845 if (!lock_task_sighand(p
, &flags
))
5847 rlim_rtprio
= p
->signal
->rlim
[RLIMIT_RTPRIO
].rlim_cur
;
5848 unlock_task_sighand(p
, &flags
);
5850 /* can't set/change the rt policy */
5851 if (policy
!= p
->policy
&& !rlim_rtprio
)
5854 /* can't increase priority */
5855 if (param
->sched_priority
> p
->rt_priority
&&
5856 param
->sched_priority
> rlim_rtprio
)
5860 * Like positive nice levels, dont allow tasks to
5861 * move out of SCHED_IDLE either:
5863 if (p
->policy
== SCHED_IDLE
&& policy
!= SCHED_IDLE
)
5866 /* can't change other user's priorities */
5867 if (!check_same_owner(p
))
5872 #ifdef CONFIG_RT_GROUP_SCHED
5874 * Do not allow realtime tasks into groups that have no runtime
5877 if (rt_bandwidth_enabled() && rt_policy(policy
) &&
5878 task_group(p
)->rt_bandwidth
.rt_runtime
== 0)
5882 retval
= security_task_setscheduler(p
, policy
, param
);
5888 * make sure no PI-waiters arrive (or leave) while we are
5889 * changing the priority of the task:
5891 spin_lock_irqsave(&p
->pi_lock
, flags
);
5893 * To be able to change p->policy safely, the apropriate
5894 * runqueue lock must be held.
5896 rq
= __task_rq_lock(p
);
5897 /* recheck policy now with rq lock held */
5898 if (unlikely(oldpolicy
!= -1 && oldpolicy
!= p
->policy
)) {
5899 policy
= oldpolicy
= -1;
5900 __task_rq_unlock(rq
);
5901 spin_unlock_irqrestore(&p
->pi_lock
, flags
);
5904 update_rq_clock(rq
);
5905 on_rq
= p
->se
.on_rq
;
5906 running
= task_current(rq
, p
);
5908 deactivate_task(rq
, p
, 0);
5910 p
->sched_class
->put_prev_task(rq
, p
);
5913 __setscheduler(rq
, p
, policy
, param
->sched_priority
);
5916 p
->sched_class
->set_curr_task(rq
);
5918 activate_task(rq
, p
, 0);
5920 check_class_changed(rq
, p
, prev_class
, oldprio
, running
);
5922 __task_rq_unlock(rq
);
5923 spin_unlock_irqrestore(&p
->pi_lock
, flags
);
5925 rt_mutex_adjust_pi(p
);
5931 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
5932 * @p: the task in question.
5933 * @policy: new policy.
5934 * @param: structure containing the new RT priority.
5936 * NOTE that the task may be already dead.
5938 int sched_setscheduler(struct task_struct
*p
, int policy
,
5939 struct sched_param
*param
)
5941 return __sched_setscheduler(p
, policy
, param
, true);
5943 EXPORT_SYMBOL_GPL(sched_setscheduler
);
5946 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
5947 * @p: the task in question.
5948 * @policy: new policy.
5949 * @param: structure containing the new RT priority.
5951 * Just like sched_setscheduler, only don't bother checking if the
5952 * current context has permission. For example, this is needed in
5953 * stop_machine(): we create temporary high priority worker threads,
5954 * but our caller might not have that capability.
5956 int sched_setscheduler_nocheck(struct task_struct
*p
, int policy
,
5957 struct sched_param
*param
)
5959 return __sched_setscheduler(p
, policy
, param
, false);
5963 do_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
5965 struct sched_param lparam
;
5966 struct task_struct
*p
;
5969 if (!param
|| pid
< 0)
5971 if (copy_from_user(&lparam
, param
, sizeof(struct sched_param
)))
5976 p
= find_process_by_pid(pid
);
5978 retval
= sched_setscheduler(p
, policy
, &lparam
);
5985 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
5986 * @pid: the pid in question.
5987 * @policy: new policy.
5988 * @param: structure containing the new RT priority.
5990 SYSCALL_DEFINE3(sched_setscheduler
, pid_t
, pid
, int, policy
,
5991 struct sched_param __user
*, param
)
5993 /* negative values for policy are not valid */
5997 return do_sched_setscheduler(pid
, policy
, param
);
6001 * sys_sched_setparam - set/change the RT priority of a thread
6002 * @pid: the pid in question.
6003 * @param: structure containing the new RT priority.
6005 SYSCALL_DEFINE2(sched_setparam
, pid_t
, pid
, struct sched_param __user
*, param
)
6007 return do_sched_setscheduler(pid
, -1, param
);
6011 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
6012 * @pid: the pid in question.
6014 SYSCALL_DEFINE1(sched_getscheduler
, pid_t
, pid
)
6016 struct task_struct
*p
;
6023 read_lock(&tasklist_lock
);
6024 p
= find_process_by_pid(pid
);
6026 retval
= security_task_getscheduler(p
);
6030 read_unlock(&tasklist_lock
);
6035 * sys_sched_getscheduler - get the RT priority of a thread
6036 * @pid: the pid in question.
6037 * @param: structure containing the RT priority.
6039 SYSCALL_DEFINE2(sched_getparam
, pid_t
, pid
, struct sched_param __user
*, param
)
6041 struct sched_param lp
;
6042 struct task_struct
*p
;
6045 if (!param
|| pid
< 0)
6048 read_lock(&tasklist_lock
);
6049 p
= find_process_by_pid(pid
);
6054 retval
= security_task_getscheduler(p
);
6058 lp
.sched_priority
= p
->rt_priority
;
6059 read_unlock(&tasklist_lock
);
6062 * This one might sleep, we cannot do it with a spinlock held ...
6064 retval
= copy_to_user(param
, &lp
, sizeof(*param
)) ? -EFAULT
: 0;
6069 read_unlock(&tasklist_lock
);
6073 long sched_setaffinity(pid_t pid
, const struct cpumask
*in_mask
)
6075 cpumask_var_t cpus_allowed
, new_mask
;
6076 struct task_struct
*p
;
6080 read_lock(&tasklist_lock
);
6082 p
= find_process_by_pid(pid
);
6084 read_unlock(&tasklist_lock
);
6090 * It is not safe to call set_cpus_allowed with the
6091 * tasklist_lock held. We will bump the task_struct's
6092 * usage count and then drop tasklist_lock.
6095 read_unlock(&tasklist_lock
);
6097 if (!alloc_cpumask_var(&cpus_allowed
, GFP_KERNEL
)) {
6101 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
)) {
6103 goto out_free_cpus_allowed
;
6106 if (!check_same_owner(p
) && !capable(CAP_SYS_NICE
))
6109 retval
= security_task_setscheduler(p
, 0, NULL
);
6113 cpuset_cpus_allowed(p
, cpus_allowed
);
6114 cpumask_and(new_mask
, in_mask
, cpus_allowed
);
6116 retval
= set_cpus_allowed_ptr(p
, new_mask
);
6119 cpuset_cpus_allowed(p
, cpus_allowed
);
6120 if (!cpumask_subset(new_mask
, cpus_allowed
)) {
6122 * We must have raced with a concurrent cpuset
6123 * update. Just reset the cpus_allowed to the
6124 * cpuset's cpus_allowed
6126 cpumask_copy(new_mask
, cpus_allowed
);
6131 free_cpumask_var(new_mask
);
6132 out_free_cpus_allowed
:
6133 free_cpumask_var(cpus_allowed
);
6140 static int get_user_cpu_mask(unsigned long __user
*user_mask_ptr
, unsigned len
,
6141 struct cpumask
*new_mask
)
6143 if (len
< cpumask_size())
6144 cpumask_clear(new_mask
);
6145 else if (len
> cpumask_size())
6146 len
= cpumask_size();
6148 return copy_from_user(new_mask
, user_mask_ptr
, len
) ? -EFAULT
: 0;
6152 * sys_sched_setaffinity - set the cpu affinity of a process
6153 * @pid: pid of the process
6154 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
6155 * @user_mask_ptr: user-space pointer to the new cpu mask
6157 SYSCALL_DEFINE3(sched_setaffinity
, pid_t
, pid
, unsigned int, len
,
6158 unsigned long __user
*, user_mask_ptr
)
6160 cpumask_var_t new_mask
;
6163 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
))
6166 retval
= get_user_cpu_mask(user_mask_ptr
, len
, new_mask
);
6168 retval
= sched_setaffinity(pid
, new_mask
);
6169 free_cpumask_var(new_mask
);
6173 long sched_getaffinity(pid_t pid
, struct cpumask
*mask
)
6175 struct task_struct
*p
;
6179 read_lock(&tasklist_lock
);
6182 p
= find_process_by_pid(pid
);
6186 retval
= security_task_getscheduler(p
);
6190 cpumask_and(mask
, &p
->cpus_allowed
, cpu_online_mask
);
6193 read_unlock(&tasklist_lock
);
6200 * sys_sched_getaffinity - get the cpu affinity of a process
6201 * @pid: pid of the process
6202 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
6203 * @user_mask_ptr: user-space pointer to hold the current cpu mask
6205 SYSCALL_DEFINE3(sched_getaffinity
, pid_t
, pid
, unsigned int, len
,
6206 unsigned long __user
*, user_mask_ptr
)
6211 if (len
< cpumask_size())
6214 if (!alloc_cpumask_var(&mask
, GFP_KERNEL
))
6217 ret
= sched_getaffinity(pid
, mask
);
6219 if (copy_to_user(user_mask_ptr
, mask
, cpumask_size()))
6222 ret
= cpumask_size();
6224 free_cpumask_var(mask
);
6230 * sys_sched_yield - yield the current processor to other threads.
6232 * This function yields the current CPU to other tasks. If there are no
6233 * other threads running on this CPU then this function will return.
6235 SYSCALL_DEFINE0(sched_yield
)
6237 struct rq
*rq
= this_rq_lock();
6239 schedstat_inc(rq
, yld_count
);
6240 current
->sched_class
->yield_task(rq
);
6243 * Since we are going to call schedule() anyway, there's
6244 * no need to preempt or enable interrupts:
6246 __release(rq
->lock
);
6247 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
6248 _raw_spin_unlock(&rq
->lock
);
6249 preempt_enable_no_resched();
6256 static void __cond_resched(void)
6258 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
6259 __might_sleep(__FILE__
, __LINE__
);
6262 * The BKS might be reacquired before we have dropped
6263 * PREEMPT_ACTIVE, which could trigger a second
6264 * cond_resched() call.
6267 add_preempt_count(PREEMPT_ACTIVE
);
6269 sub_preempt_count(PREEMPT_ACTIVE
);
6270 } while (need_resched());
6273 int __sched
_cond_resched(void)
6275 if (need_resched() && !(preempt_count() & PREEMPT_ACTIVE
) &&
6276 system_state
== SYSTEM_RUNNING
) {
6282 EXPORT_SYMBOL(_cond_resched
);
6285 * cond_resched_lock() - if a reschedule is pending, drop the given lock,
6286 * call schedule, and on return reacquire the lock.
6288 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
6289 * operations here to prevent schedule() from being called twice (once via
6290 * spin_unlock(), once by hand).
6292 int cond_resched_lock(spinlock_t
*lock
)
6294 int resched
= need_resched() && system_state
== SYSTEM_RUNNING
;
6297 if (spin_needbreak(lock
) || resched
) {
6299 if (resched
&& need_resched())
6308 EXPORT_SYMBOL(cond_resched_lock
);
6310 int __sched
cond_resched_softirq(void)
6312 BUG_ON(!in_softirq());
6314 if (need_resched() && system_state
== SYSTEM_RUNNING
) {
6322 EXPORT_SYMBOL(cond_resched_softirq
);
6325 * yield - yield the current processor to other threads.
6327 * This is a shortcut for kernel-space yielding - it marks the
6328 * thread runnable and calls sys_sched_yield().
6330 void __sched
yield(void)
6332 set_current_state(TASK_RUNNING
);
6335 EXPORT_SYMBOL(yield
);
6338 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
6339 * that process accounting knows that this is a task in IO wait state.
6341 * But don't do that if it is a deliberate, throttling IO wait (this task
6342 * has set its backing_dev_info: the queue against which it should throttle)
6344 void __sched
io_schedule(void)
6346 struct rq
*rq
= &__raw_get_cpu_var(runqueues
);
6348 delayacct_blkio_start();
6349 atomic_inc(&rq
->nr_iowait
);
6351 atomic_dec(&rq
->nr_iowait
);
6352 delayacct_blkio_end();
6354 EXPORT_SYMBOL(io_schedule
);
6356 long __sched
io_schedule_timeout(long timeout
)
6358 struct rq
*rq
= &__raw_get_cpu_var(runqueues
);
6361 delayacct_blkio_start();
6362 atomic_inc(&rq
->nr_iowait
);
6363 ret
= schedule_timeout(timeout
);
6364 atomic_dec(&rq
->nr_iowait
);
6365 delayacct_blkio_end();
6370 * sys_sched_get_priority_max - return maximum RT priority.
6371 * @policy: scheduling class.
6373 * this syscall returns the maximum rt_priority that can be used
6374 * by a given scheduling class.
6376 SYSCALL_DEFINE1(sched_get_priority_max
, int, policy
)
6383 ret
= MAX_USER_RT_PRIO
-1;
6395 * sys_sched_get_priority_min - return minimum RT priority.
6396 * @policy: scheduling class.
6398 * this syscall returns the minimum rt_priority that can be used
6399 * by a given scheduling class.
6401 SYSCALL_DEFINE1(sched_get_priority_min
, int, policy
)
6419 * sys_sched_rr_get_interval - return the default timeslice of a process.
6420 * @pid: pid of the process.
6421 * @interval: userspace pointer to the timeslice value.
6423 * this syscall writes the default timeslice value of a given process
6424 * into the user-space timespec buffer. A value of '0' means infinity.
6426 SYSCALL_DEFINE2(sched_rr_get_interval
, pid_t
, pid
,
6427 struct timespec __user
*, interval
)
6429 struct task_struct
*p
;
6430 unsigned int time_slice
;
6438 read_lock(&tasklist_lock
);
6439 p
= find_process_by_pid(pid
);
6443 retval
= security_task_getscheduler(p
);
6448 * Time slice is 0 for SCHED_FIFO tasks and for SCHED_OTHER
6449 * tasks that are on an otherwise idle runqueue:
6452 if (p
->policy
== SCHED_RR
) {
6453 time_slice
= DEF_TIMESLICE
;
6454 } else if (p
->policy
!= SCHED_FIFO
) {
6455 struct sched_entity
*se
= &p
->se
;
6456 unsigned long flags
;
6459 rq
= task_rq_lock(p
, &flags
);
6460 if (rq
->cfs
.load
.weight
)
6461 time_slice
= NS_TO_JIFFIES(sched_slice(&rq
->cfs
, se
));
6462 task_rq_unlock(rq
, &flags
);
6464 read_unlock(&tasklist_lock
);
6465 jiffies_to_timespec(time_slice
, &t
);
6466 retval
= copy_to_user(interval
, &t
, sizeof(t
)) ? -EFAULT
: 0;
6470 read_unlock(&tasklist_lock
);
6474 static const char stat_nam
[] = TASK_STATE_TO_CHAR_STR
;
6476 void sched_show_task(struct task_struct
*p
)
6478 unsigned long free
= 0;
6481 state
= p
->state
? __ffs(p
->state
) + 1 : 0;
6482 printk(KERN_INFO
"%-13.13s %c", p
->comm
,
6483 state
< sizeof(stat_nam
) - 1 ? stat_nam
[state
] : '?');
6484 #if BITS_PER_LONG == 32
6485 if (state
== TASK_RUNNING
)
6486 printk(KERN_CONT
" running ");
6488 printk(KERN_CONT
" %08lx ", thread_saved_pc(p
));
6490 if (state
== TASK_RUNNING
)
6491 printk(KERN_CONT
" running task ");
6493 printk(KERN_CONT
" %016lx ", thread_saved_pc(p
));
6495 #ifdef CONFIG_DEBUG_STACK_USAGE
6496 free
= stack_not_used(p
);
6498 printk(KERN_CONT
"%5lu %5d %6d\n", free
,
6499 task_pid_nr(p
), task_pid_nr(p
->real_parent
));
6501 show_stack(p
, NULL
);
6504 void show_state_filter(unsigned long state_filter
)
6506 struct task_struct
*g
, *p
;
6508 #if BITS_PER_LONG == 32
6510 " task PC stack pid father\n");
6513 " task PC stack pid father\n");
6515 read_lock(&tasklist_lock
);
6516 do_each_thread(g
, p
) {
6518 * reset the NMI-timeout, listing all files on a slow
6519 * console might take alot of time:
6521 touch_nmi_watchdog();
6522 if (!state_filter
|| (p
->state
& state_filter
))
6524 } while_each_thread(g
, p
);
6526 touch_all_softlockup_watchdogs();
6528 #ifdef CONFIG_SCHED_DEBUG
6529 sysrq_sched_debug_show();
6531 read_unlock(&tasklist_lock
);
6533 * Only show locks if all tasks are dumped:
6535 if (state_filter
== -1)
6536 debug_show_all_locks();
6539 void __cpuinit
init_idle_bootup_task(struct task_struct
*idle
)
6541 idle
->sched_class
= &idle_sched_class
;
6545 * init_idle - set up an idle thread for a given CPU
6546 * @idle: task in question
6547 * @cpu: cpu the idle task belongs to
6549 * NOTE: this function does not set the idle thread's NEED_RESCHED
6550 * flag, to make booting more robust.
6552 void __cpuinit
init_idle(struct task_struct
*idle
, int cpu
)
6554 struct rq
*rq
= cpu_rq(cpu
);
6555 unsigned long flags
;
6557 spin_lock_irqsave(&rq
->lock
, flags
);
6560 idle
->se
.exec_start
= sched_clock();
6562 idle
->prio
= idle
->normal_prio
= MAX_PRIO
;
6563 cpumask_copy(&idle
->cpus_allowed
, cpumask_of(cpu
));
6564 __set_task_cpu(idle
, cpu
);
6566 rq
->curr
= rq
->idle
= idle
;
6567 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
6570 spin_unlock_irqrestore(&rq
->lock
, flags
);
6572 /* Set the preempt count _outside_ the spinlocks! */
6573 #if defined(CONFIG_PREEMPT)
6574 task_thread_info(idle
)->preempt_count
= (idle
->lock_depth
>= 0);
6576 task_thread_info(idle
)->preempt_count
= 0;
6579 * The idle tasks have their own, simple scheduling class:
6581 idle
->sched_class
= &idle_sched_class
;
6582 ftrace_graph_init_task(idle
);
6586 * In a system that switches off the HZ timer nohz_cpu_mask
6587 * indicates which cpus entered this state. This is used
6588 * in the rcu update to wait only for active cpus. For system
6589 * which do not switch off the HZ timer nohz_cpu_mask should
6590 * always be CPU_BITS_NONE.
6592 cpumask_var_t nohz_cpu_mask
;
6595 * Increase the granularity value when there are more CPUs,
6596 * because with more CPUs the 'effective latency' as visible
6597 * to users decreases. But the relationship is not linear,
6598 * so pick a second-best guess by going with the log2 of the
6601 * This idea comes from the SD scheduler of Con Kolivas:
6603 static inline void sched_init_granularity(void)
6605 unsigned int factor
= 1 + ilog2(num_online_cpus());
6606 const unsigned long limit
= 200000000;
6608 sysctl_sched_min_granularity
*= factor
;
6609 if (sysctl_sched_min_granularity
> limit
)
6610 sysctl_sched_min_granularity
= limit
;
6612 sysctl_sched_latency
*= factor
;
6613 if (sysctl_sched_latency
> limit
)
6614 sysctl_sched_latency
= limit
;
6616 sysctl_sched_wakeup_granularity
*= factor
;
6618 sysctl_sched_shares_ratelimit
*= factor
;
6623 * This is how migration works:
6625 * 1) we queue a struct migration_req structure in the source CPU's
6626 * runqueue and wake up that CPU's migration thread.
6627 * 2) we down() the locked semaphore => thread blocks.
6628 * 3) migration thread wakes up (implicitly it forces the migrated
6629 * thread off the CPU)
6630 * 4) it gets the migration request and checks whether the migrated
6631 * task is still in the wrong runqueue.
6632 * 5) if it's in the wrong runqueue then the migration thread removes
6633 * it and puts it into the right queue.
6634 * 6) migration thread up()s the semaphore.
6635 * 7) we wake up and the migration is done.
6639 * Change a given task's CPU affinity. Migrate the thread to a
6640 * proper CPU and schedule it away if the CPU it's executing on
6641 * is removed from the allowed bitmask.
6643 * NOTE: the caller must have a valid reference to the task, the
6644 * task must not exit() & deallocate itself prematurely. The
6645 * call is not atomic; no spinlocks may be held.
6647 int set_cpus_allowed_ptr(struct task_struct
*p
, const struct cpumask
*new_mask
)
6649 struct migration_req req
;
6650 unsigned long flags
;
6654 rq
= task_rq_lock(p
, &flags
);
6655 if (!cpumask_intersects(new_mask
, cpu_online_mask
)) {
6660 if (unlikely((p
->flags
& PF_THREAD_BOUND
) && p
!= current
&&
6661 !cpumask_equal(&p
->cpus_allowed
, new_mask
))) {
6666 if (p
->sched_class
->set_cpus_allowed
)
6667 p
->sched_class
->set_cpus_allowed(p
, new_mask
);
6669 cpumask_copy(&p
->cpus_allowed
, new_mask
);
6670 p
->rt
.nr_cpus_allowed
= cpumask_weight(new_mask
);
6673 /* Can the task run on the task's current CPU? If so, we're done */
6674 if (cpumask_test_cpu(task_cpu(p
), new_mask
))
6677 if (migrate_task(p
, cpumask_any_and(cpu_online_mask
, new_mask
), &req
)) {
6678 /* Need help from migration thread: drop lock and wait. */
6679 task_rq_unlock(rq
, &flags
);
6680 wake_up_process(rq
->migration_thread
);
6681 wait_for_completion(&req
.done
);
6682 tlb_migrate_finish(p
->mm
);
6686 task_rq_unlock(rq
, &flags
);
6690 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr
);
6693 * Move (not current) task off this cpu, onto dest cpu. We're doing
6694 * this because either it can't run here any more (set_cpus_allowed()
6695 * away from this CPU, or CPU going down), or because we're
6696 * attempting to rebalance this task on exec (sched_exec).
6698 * So we race with normal scheduler movements, but that's OK, as long
6699 * as the task is no longer on this CPU.
6701 * Returns non-zero if task was successfully migrated.
6703 static int __migrate_task(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
6705 struct rq
*rq_dest
, *rq_src
;
6708 if (unlikely(!cpu_active(dest_cpu
)))
6711 rq_src
= cpu_rq(src_cpu
);
6712 rq_dest
= cpu_rq(dest_cpu
);
6714 double_rq_lock(rq_src
, rq_dest
);
6715 /* Already moved. */
6716 if (task_cpu(p
) != src_cpu
)
6718 /* Affinity changed (again). */
6719 if (!cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
))
6722 on_rq
= p
->se
.on_rq
;
6724 deactivate_task(rq_src
, p
, 0);
6726 set_task_cpu(p
, dest_cpu
);
6728 activate_task(rq_dest
, p
, 0);
6729 check_preempt_curr(rq_dest
, p
, 0);
6734 double_rq_unlock(rq_src
, rq_dest
);
6739 * migration_thread - this is a highprio system thread that performs
6740 * thread migration by bumping thread off CPU then 'pushing' onto
6743 static int migration_thread(void *data
)
6745 int cpu
= (long)data
;
6749 BUG_ON(rq
->migration_thread
!= current
);
6751 set_current_state(TASK_INTERRUPTIBLE
);
6752 while (!kthread_should_stop()) {
6753 struct migration_req
*req
;
6754 struct list_head
*head
;
6756 spin_lock_irq(&rq
->lock
);
6758 if (cpu_is_offline(cpu
)) {
6759 spin_unlock_irq(&rq
->lock
);
6763 if (rq
->active_balance
) {
6764 active_load_balance(rq
, cpu
);
6765 rq
->active_balance
= 0;
6768 head
= &rq
->migration_queue
;
6770 if (list_empty(head
)) {
6771 spin_unlock_irq(&rq
->lock
);
6773 set_current_state(TASK_INTERRUPTIBLE
);
6776 req
= list_entry(head
->next
, struct migration_req
, list
);
6777 list_del_init(head
->next
);
6779 spin_unlock(&rq
->lock
);
6780 __migrate_task(req
->task
, cpu
, req
->dest_cpu
);
6783 complete(&req
->done
);
6785 __set_current_state(TASK_RUNNING
);
6789 /* Wait for kthread_stop */
6790 set_current_state(TASK_INTERRUPTIBLE
);
6791 while (!kthread_should_stop()) {
6793 set_current_state(TASK_INTERRUPTIBLE
);
6795 __set_current_state(TASK_RUNNING
);
6799 #ifdef CONFIG_HOTPLUG_CPU
6801 static int __migrate_task_irq(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
6805 local_irq_disable();
6806 ret
= __migrate_task(p
, src_cpu
, dest_cpu
);
6812 * Figure out where task on dead CPU should go, use force if necessary.
6814 static void move_task_off_dead_cpu(int dead_cpu
, struct task_struct
*p
)
6817 const struct cpumask
*nodemask
= cpumask_of_node(cpu_to_node(dead_cpu
));
6820 /* Look for allowed, online CPU in same node. */
6821 for_each_cpu_and(dest_cpu
, nodemask
, cpu_online_mask
)
6822 if (cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
))
6825 /* Any allowed, online CPU? */
6826 dest_cpu
= cpumask_any_and(&p
->cpus_allowed
, cpu_online_mask
);
6827 if (dest_cpu
< nr_cpu_ids
)
6830 /* No more Mr. Nice Guy. */
6831 if (dest_cpu
>= nr_cpu_ids
) {
6832 cpuset_cpus_allowed_locked(p
, &p
->cpus_allowed
);
6833 dest_cpu
= cpumask_any_and(cpu_online_mask
, &p
->cpus_allowed
);
6836 * Don't tell them about moving exiting tasks or
6837 * kernel threads (both mm NULL), since they never
6840 if (p
->mm
&& printk_ratelimit()) {
6841 printk(KERN_INFO
"process %d (%s) no "
6842 "longer affine to cpu%d\n",
6843 task_pid_nr(p
), p
->comm
, dead_cpu
);
6848 /* It can have affinity changed while we were choosing. */
6849 if (unlikely(!__migrate_task_irq(p
, dead_cpu
, dest_cpu
)))
6854 * While a dead CPU has no uninterruptible tasks queued at this point,
6855 * it might still have a nonzero ->nr_uninterruptible counter, because
6856 * for performance reasons the counter is not stricly tracking tasks to
6857 * their home CPUs. So we just add the counter to another CPU's counter,
6858 * to keep the global sum constant after CPU-down:
6860 static void migrate_nr_uninterruptible(struct rq
*rq_src
)
6862 struct rq
*rq_dest
= cpu_rq(cpumask_any(cpu_online_mask
));
6863 unsigned long flags
;
6865 local_irq_save(flags
);
6866 double_rq_lock(rq_src
, rq_dest
);
6867 rq_dest
->nr_uninterruptible
+= rq_src
->nr_uninterruptible
;
6868 rq_src
->nr_uninterruptible
= 0;
6869 double_rq_unlock(rq_src
, rq_dest
);
6870 local_irq_restore(flags
);
6873 /* Run through task list and migrate tasks from the dead cpu. */
6874 static void migrate_live_tasks(int src_cpu
)
6876 struct task_struct
*p
, *t
;
6878 read_lock(&tasklist_lock
);
6880 do_each_thread(t
, p
) {
6884 if (task_cpu(p
) == src_cpu
)
6885 move_task_off_dead_cpu(src_cpu
, p
);
6886 } while_each_thread(t
, p
);
6888 read_unlock(&tasklist_lock
);
6892 * Schedules idle task to be the next runnable task on current CPU.
6893 * It does so by boosting its priority to highest possible.
6894 * Used by CPU offline code.
6896 void sched_idle_next(void)
6898 int this_cpu
= smp_processor_id();
6899 struct rq
*rq
= cpu_rq(this_cpu
);
6900 struct task_struct
*p
= rq
->idle
;
6901 unsigned long flags
;
6903 /* cpu has to be offline */
6904 BUG_ON(cpu_online(this_cpu
));
6907 * Strictly not necessary since rest of the CPUs are stopped by now
6908 * and interrupts disabled on the current cpu.
6910 spin_lock_irqsave(&rq
->lock
, flags
);
6912 __setscheduler(rq
, p
, SCHED_FIFO
, MAX_RT_PRIO
-1);
6914 update_rq_clock(rq
);
6915 activate_task(rq
, p
, 0);
6917 spin_unlock_irqrestore(&rq
->lock
, flags
);
6921 * Ensures that the idle task is using init_mm right before its cpu goes
6924 void idle_task_exit(void)
6926 struct mm_struct
*mm
= current
->active_mm
;
6928 BUG_ON(cpu_online(smp_processor_id()));
6931 switch_mm(mm
, &init_mm
, current
);
6935 /* called under rq->lock with disabled interrupts */
6936 static void migrate_dead(unsigned int dead_cpu
, struct task_struct
*p
)
6938 struct rq
*rq
= cpu_rq(dead_cpu
);
6940 /* Must be exiting, otherwise would be on tasklist. */
6941 BUG_ON(!p
->exit_state
);
6943 /* Cannot have done final schedule yet: would have vanished. */
6944 BUG_ON(p
->state
== TASK_DEAD
);
6949 * Drop lock around migration; if someone else moves it,
6950 * that's OK. No task can be added to this CPU, so iteration is
6953 spin_unlock_irq(&rq
->lock
);
6954 move_task_off_dead_cpu(dead_cpu
, p
);
6955 spin_lock_irq(&rq
->lock
);
6960 /* release_task() removes task from tasklist, so we won't find dead tasks. */
6961 static void migrate_dead_tasks(unsigned int dead_cpu
)
6963 struct rq
*rq
= cpu_rq(dead_cpu
);
6964 struct task_struct
*next
;
6967 if (!rq
->nr_running
)
6969 update_rq_clock(rq
);
6970 next
= pick_next_task(rq
);
6973 next
->sched_class
->put_prev_task(rq
, next
);
6974 migrate_dead(dead_cpu
, next
);
6978 #endif /* CONFIG_HOTPLUG_CPU */
6980 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
6982 static struct ctl_table sd_ctl_dir
[] = {
6984 .procname
= "sched_domain",
6990 static struct ctl_table sd_ctl_root
[] = {
6992 .ctl_name
= CTL_KERN
,
6993 .procname
= "kernel",
6995 .child
= sd_ctl_dir
,
7000 static struct ctl_table
*sd_alloc_ctl_entry(int n
)
7002 struct ctl_table
*entry
=
7003 kcalloc(n
, sizeof(struct ctl_table
), GFP_KERNEL
);
7008 static void sd_free_ctl_entry(struct ctl_table
**tablep
)
7010 struct ctl_table
*entry
;
7013 * In the intermediate directories, both the child directory and
7014 * procname are dynamically allocated and could fail but the mode
7015 * will always be set. In the lowest directory the names are
7016 * static strings and all have proc handlers.
7018 for (entry
= *tablep
; entry
->mode
; entry
++) {
7020 sd_free_ctl_entry(&entry
->child
);
7021 if (entry
->proc_handler
== NULL
)
7022 kfree(entry
->procname
);
7030 set_table_entry(struct ctl_table
*entry
,
7031 const char *procname
, void *data
, int maxlen
,
7032 mode_t mode
, proc_handler
*proc_handler
)
7034 entry
->procname
= procname
;
7036 entry
->maxlen
= maxlen
;
7038 entry
->proc_handler
= proc_handler
;
7041 static struct ctl_table
*
7042 sd_alloc_ctl_domain_table(struct sched_domain
*sd
)
7044 struct ctl_table
*table
= sd_alloc_ctl_entry(13);
7049 set_table_entry(&table
[0], "min_interval", &sd
->min_interval
,
7050 sizeof(long), 0644, proc_doulongvec_minmax
);
7051 set_table_entry(&table
[1], "max_interval", &sd
->max_interval
,
7052 sizeof(long), 0644, proc_doulongvec_minmax
);
7053 set_table_entry(&table
[2], "busy_idx", &sd
->busy_idx
,
7054 sizeof(int), 0644, proc_dointvec_minmax
);
7055 set_table_entry(&table
[3], "idle_idx", &sd
->idle_idx
,
7056 sizeof(int), 0644, proc_dointvec_minmax
);
7057 set_table_entry(&table
[4], "newidle_idx", &sd
->newidle_idx
,
7058 sizeof(int), 0644, proc_dointvec_minmax
);
7059 set_table_entry(&table
[5], "wake_idx", &sd
->wake_idx
,
7060 sizeof(int), 0644, proc_dointvec_minmax
);
7061 set_table_entry(&table
[6], "forkexec_idx", &sd
->forkexec_idx
,
7062 sizeof(int), 0644, proc_dointvec_minmax
);
7063 set_table_entry(&table
[7], "busy_factor", &sd
->busy_factor
,
7064 sizeof(int), 0644, proc_dointvec_minmax
);
7065 set_table_entry(&table
[8], "imbalance_pct", &sd
->imbalance_pct
,
7066 sizeof(int), 0644, proc_dointvec_minmax
);
7067 set_table_entry(&table
[9], "cache_nice_tries",
7068 &sd
->cache_nice_tries
,
7069 sizeof(int), 0644, proc_dointvec_minmax
);
7070 set_table_entry(&table
[10], "flags", &sd
->flags
,
7071 sizeof(int), 0644, proc_dointvec_minmax
);
7072 set_table_entry(&table
[11], "name", sd
->name
,
7073 CORENAME_MAX_SIZE
, 0444, proc_dostring
);
7074 /* &table[12] is terminator */
7079 static ctl_table
*sd_alloc_ctl_cpu_table(int cpu
)
7081 struct ctl_table
*entry
, *table
;
7082 struct sched_domain
*sd
;
7083 int domain_num
= 0, i
;
7086 for_each_domain(cpu
, sd
)
7088 entry
= table
= sd_alloc_ctl_entry(domain_num
+ 1);
7093 for_each_domain(cpu
, sd
) {
7094 snprintf(buf
, 32, "domain%d", i
);
7095 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
7097 entry
->child
= sd_alloc_ctl_domain_table(sd
);
7104 static struct ctl_table_header
*sd_sysctl_header
;
7105 static void register_sched_domain_sysctl(void)
7107 int i
, cpu_num
= num_online_cpus();
7108 struct ctl_table
*entry
= sd_alloc_ctl_entry(cpu_num
+ 1);
7111 WARN_ON(sd_ctl_dir
[0].child
);
7112 sd_ctl_dir
[0].child
= entry
;
7117 for_each_online_cpu(i
) {
7118 snprintf(buf
, 32, "cpu%d", i
);
7119 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
7121 entry
->child
= sd_alloc_ctl_cpu_table(i
);
7125 WARN_ON(sd_sysctl_header
);
7126 sd_sysctl_header
= register_sysctl_table(sd_ctl_root
);
7129 /* may be called multiple times per register */
7130 static void unregister_sched_domain_sysctl(void)
7132 if (sd_sysctl_header
)
7133 unregister_sysctl_table(sd_sysctl_header
);
7134 sd_sysctl_header
= NULL
;
7135 if (sd_ctl_dir
[0].child
)
7136 sd_free_ctl_entry(&sd_ctl_dir
[0].child
);
7139 static void register_sched_domain_sysctl(void)
7142 static void unregister_sched_domain_sysctl(void)
7147 static void set_rq_online(struct rq
*rq
)
7150 const struct sched_class
*class;
7152 cpumask_set_cpu(rq
->cpu
, rq
->rd
->online
);
7155 for_each_class(class) {
7156 if (class->rq_online
)
7157 class->rq_online(rq
);
7162 static void set_rq_offline(struct rq
*rq
)
7165 const struct sched_class
*class;
7167 for_each_class(class) {
7168 if (class->rq_offline
)
7169 class->rq_offline(rq
);
7172 cpumask_clear_cpu(rq
->cpu
, rq
->rd
->online
);
7178 * migration_call - callback that gets triggered when a CPU is added.
7179 * Here we can start up the necessary migration thread for the new CPU.
7181 static int __cpuinit
7182 migration_call(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
7184 struct task_struct
*p
;
7185 int cpu
= (long)hcpu
;
7186 unsigned long flags
;
7191 case CPU_UP_PREPARE
:
7192 case CPU_UP_PREPARE_FROZEN
:
7193 p
= kthread_create(migration_thread
, hcpu
, "migration/%d", cpu
);
7196 kthread_bind(p
, cpu
);
7197 /* Must be high prio: stop_machine expects to yield to it. */
7198 rq
= task_rq_lock(p
, &flags
);
7199 __setscheduler(rq
, p
, SCHED_FIFO
, MAX_RT_PRIO
-1);
7200 task_rq_unlock(rq
, &flags
);
7201 cpu_rq(cpu
)->migration_thread
= p
;
7205 case CPU_ONLINE_FROZEN
:
7206 /* Strictly unnecessary, as first user will wake it. */
7207 wake_up_process(cpu_rq(cpu
)->migration_thread
);
7209 /* Update our root-domain */
7211 spin_lock_irqsave(&rq
->lock
, flags
);
7213 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
7217 spin_unlock_irqrestore(&rq
->lock
, flags
);
7220 #ifdef CONFIG_HOTPLUG_CPU
7221 case CPU_UP_CANCELED
:
7222 case CPU_UP_CANCELED_FROZEN
:
7223 if (!cpu_rq(cpu
)->migration_thread
)
7225 /* Unbind it from offline cpu so it can run. Fall thru. */
7226 kthread_bind(cpu_rq(cpu
)->migration_thread
,
7227 cpumask_any(cpu_online_mask
));
7228 kthread_stop(cpu_rq(cpu
)->migration_thread
);
7229 cpu_rq(cpu
)->migration_thread
= NULL
;
7233 case CPU_DEAD_FROZEN
:
7234 cpuset_lock(); /* around calls to cpuset_cpus_allowed_lock() */
7235 migrate_live_tasks(cpu
);
7237 kthread_stop(rq
->migration_thread
);
7238 rq
->migration_thread
= NULL
;
7239 /* Idle task back to normal (off runqueue, low prio) */
7240 spin_lock_irq(&rq
->lock
);
7241 update_rq_clock(rq
);
7242 deactivate_task(rq
, rq
->idle
, 0);
7243 rq
->idle
->static_prio
= MAX_PRIO
;
7244 __setscheduler(rq
, rq
->idle
, SCHED_NORMAL
, 0);
7245 rq
->idle
->sched_class
= &idle_sched_class
;
7246 migrate_dead_tasks(cpu
);
7247 spin_unlock_irq(&rq
->lock
);
7249 migrate_nr_uninterruptible(rq
);
7250 BUG_ON(rq
->nr_running
!= 0);
7253 * No need to migrate the tasks: it was best-effort if
7254 * they didn't take sched_hotcpu_mutex. Just wake up
7257 spin_lock_irq(&rq
->lock
);
7258 while (!list_empty(&rq
->migration_queue
)) {
7259 struct migration_req
*req
;
7261 req
= list_entry(rq
->migration_queue
.next
,
7262 struct migration_req
, list
);
7263 list_del_init(&req
->list
);
7264 spin_unlock_irq(&rq
->lock
);
7265 complete(&req
->done
);
7266 spin_lock_irq(&rq
->lock
);
7268 spin_unlock_irq(&rq
->lock
);
7272 case CPU_DYING_FROZEN
:
7273 /* Update our root-domain */
7275 spin_lock_irqsave(&rq
->lock
, flags
);
7277 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
7280 spin_unlock_irqrestore(&rq
->lock
, flags
);
7287 /* Register at highest priority so that task migration (migrate_all_tasks)
7288 * happens before everything else.
7290 static struct notifier_block __cpuinitdata migration_notifier
= {
7291 .notifier_call
= migration_call
,
7295 static int __init
migration_init(void)
7297 void *cpu
= (void *)(long)smp_processor_id();
7300 /* Start one for the boot CPU: */
7301 err
= migration_call(&migration_notifier
, CPU_UP_PREPARE
, cpu
);
7302 BUG_ON(err
== NOTIFY_BAD
);
7303 migration_call(&migration_notifier
, CPU_ONLINE
, cpu
);
7304 register_cpu_notifier(&migration_notifier
);
7308 early_initcall(migration_init
);
7313 #ifdef CONFIG_SCHED_DEBUG
7315 static int sched_domain_debug_one(struct sched_domain
*sd
, int cpu
, int level
,
7316 struct cpumask
*groupmask
)
7318 struct sched_group
*group
= sd
->groups
;
7321 cpulist_scnprintf(str
, sizeof(str
), sched_domain_span(sd
));
7322 cpumask_clear(groupmask
);
7324 printk(KERN_DEBUG
"%*s domain %d: ", level
, "", level
);
7326 if (!(sd
->flags
& SD_LOAD_BALANCE
)) {
7327 printk("does not load-balance\n");
7329 printk(KERN_ERR
"ERROR: !SD_LOAD_BALANCE domain"
7334 printk(KERN_CONT
"span %s level %s\n", str
, sd
->name
);
7336 if (!cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
7337 printk(KERN_ERR
"ERROR: domain->span does not contain "
7340 if (!cpumask_test_cpu(cpu
, sched_group_cpus(group
))) {
7341 printk(KERN_ERR
"ERROR: domain->groups does not contain"
7345 printk(KERN_DEBUG
"%*s groups:", level
+ 1, "");
7349 printk(KERN_ERR
"ERROR: group is NULL\n");
7353 if (!group
->__cpu_power
) {
7354 printk(KERN_CONT
"\n");
7355 printk(KERN_ERR
"ERROR: domain->cpu_power not "
7360 if (!cpumask_weight(sched_group_cpus(group
))) {
7361 printk(KERN_CONT
"\n");
7362 printk(KERN_ERR
"ERROR: empty group\n");
7366 if (cpumask_intersects(groupmask
, sched_group_cpus(group
))) {
7367 printk(KERN_CONT
"\n");
7368 printk(KERN_ERR
"ERROR: repeated CPUs\n");
7372 cpumask_or(groupmask
, groupmask
, sched_group_cpus(group
));
7374 cpulist_scnprintf(str
, sizeof(str
), sched_group_cpus(group
));
7376 printk(KERN_CONT
" %s", str
);
7377 if (group
->__cpu_power
!= SCHED_LOAD_SCALE
) {
7378 printk(KERN_CONT
" (__cpu_power = %d)",
7379 group
->__cpu_power
);
7382 group
= group
->next
;
7383 } while (group
!= sd
->groups
);
7384 printk(KERN_CONT
"\n");
7386 if (!cpumask_equal(sched_domain_span(sd
), groupmask
))
7387 printk(KERN_ERR
"ERROR: groups don't span domain->span\n");
7390 !cpumask_subset(groupmask
, sched_domain_span(sd
->parent
)))
7391 printk(KERN_ERR
"ERROR: parent span is not a superset "
7392 "of domain->span\n");
7396 static void sched_domain_debug(struct sched_domain
*sd
, int cpu
)
7398 cpumask_var_t groupmask
;
7402 printk(KERN_DEBUG
"CPU%d attaching NULL sched-domain.\n", cpu
);
7406 printk(KERN_DEBUG
"CPU%d attaching sched-domain:\n", cpu
);
7408 if (!alloc_cpumask_var(&groupmask
, GFP_KERNEL
)) {
7409 printk(KERN_DEBUG
"Cannot load-balance (out of memory)\n");
7414 if (sched_domain_debug_one(sd
, cpu
, level
, groupmask
))
7421 free_cpumask_var(groupmask
);
7423 #else /* !CONFIG_SCHED_DEBUG */
7424 # define sched_domain_debug(sd, cpu) do { } while (0)
7425 #endif /* CONFIG_SCHED_DEBUG */
7427 static int sd_degenerate(struct sched_domain
*sd
)
7429 if (cpumask_weight(sched_domain_span(sd
)) == 1)
7432 /* Following flags need at least 2 groups */
7433 if (sd
->flags
& (SD_LOAD_BALANCE
|
7434 SD_BALANCE_NEWIDLE
|
7438 SD_SHARE_PKG_RESOURCES
)) {
7439 if (sd
->groups
!= sd
->groups
->next
)
7443 /* Following flags don't use groups */
7444 if (sd
->flags
& (SD_WAKE_IDLE
|
7453 sd_parent_degenerate(struct sched_domain
*sd
, struct sched_domain
*parent
)
7455 unsigned long cflags
= sd
->flags
, pflags
= parent
->flags
;
7457 if (sd_degenerate(parent
))
7460 if (!cpumask_equal(sched_domain_span(sd
), sched_domain_span(parent
)))
7463 /* Does parent contain flags not in child? */
7464 /* WAKE_BALANCE is a subset of WAKE_AFFINE */
7465 if (cflags
& SD_WAKE_AFFINE
)
7466 pflags
&= ~SD_WAKE_BALANCE
;
7467 /* Flags needing groups don't count if only 1 group in parent */
7468 if (parent
->groups
== parent
->groups
->next
) {
7469 pflags
&= ~(SD_LOAD_BALANCE
|
7470 SD_BALANCE_NEWIDLE
|
7474 SD_SHARE_PKG_RESOURCES
);
7475 if (nr_node_ids
== 1)
7476 pflags
&= ~SD_SERIALIZE
;
7478 if (~cflags
& pflags
)
7484 static void free_rootdomain(struct root_domain
*rd
)
7486 cpupri_cleanup(&rd
->cpupri
);
7488 free_cpumask_var(rd
->rto_mask
);
7489 free_cpumask_var(rd
->online
);
7490 free_cpumask_var(rd
->span
);
7494 static void rq_attach_root(struct rq
*rq
, struct root_domain
*rd
)
7496 struct root_domain
*old_rd
= NULL
;
7497 unsigned long flags
;
7499 spin_lock_irqsave(&rq
->lock
, flags
);
7504 if (cpumask_test_cpu(rq
->cpu
, old_rd
->online
))
7507 cpumask_clear_cpu(rq
->cpu
, old_rd
->span
);
7510 * If we dont want to free the old_rt yet then
7511 * set old_rd to NULL to skip the freeing later
7514 if (!atomic_dec_and_test(&old_rd
->refcount
))
7518 atomic_inc(&rd
->refcount
);
7521 cpumask_set_cpu(rq
->cpu
, rd
->span
);
7522 if (cpumask_test_cpu(rq
->cpu
, cpu_online_mask
))
7525 spin_unlock_irqrestore(&rq
->lock
, flags
);
7528 free_rootdomain(old_rd
);
7531 static int __init_refok
init_rootdomain(struct root_domain
*rd
, bool bootmem
)
7533 memset(rd
, 0, sizeof(*rd
));
7536 alloc_bootmem_cpumask_var(&def_root_domain
.span
);
7537 alloc_bootmem_cpumask_var(&def_root_domain
.online
);
7538 alloc_bootmem_cpumask_var(&def_root_domain
.rto_mask
);
7539 cpupri_init(&rd
->cpupri
, true);
7543 if (!alloc_cpumask_var(&rd
->span
, GFP_KERNEL
))
7545 if (!alloc_cpumask_var(&rd
->online
, GFP_KERNEL
))
7547 if (!alloc_cpumask_var(&rd
->rto_mask
, GFP_KERNEL
))
7550 if (cpupri_init(&rd
->cpupri
, false) != 0)
7555 free_cpumask_var(rd
->rto_mask
);
7557 free_cpumask_var(rd
->online
);
7559 free_cpumask_var(rd
->span
);
7564 static void init_defrootdomain(void)
7566 init_rootdomain(&def_root_domain
, true);
7568 atomic_set(&def_root_domain
.refcount
, 1);
7571 static struct root_domain
*alloc_rootdomain(void)
7573 struct root_domain
*rd
;
7575 rd
= kmalloc(sizeof(*rd
), GFP_KERNEL
);
7579 if (init_rootdomain(rd
, false) != 0) {
7588 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
7589 * hold the hotplug lock.
7592 cpu_attach_domain(struct sched_domain
*sd
, struct root_domain
*rd
, int cpu
)
7594 struct rq
*rq
= cpu_rq(cpu
);
7595 struct sched_domain
*tmp
;
7597 /* Remove the sched domains which do not contribute to scheduling. */
7598 for (tmp
= sd
; tmp
; ) {
7599 struct sched_domain
*parent
= tmp
->parent
;
7603 if (sd_parent_degenerate(tmp
, parent
)) {
7604 tmp
->parent
= parent
->parent
;
7606 parent
->parent
->child
= tmp
;
7611 if (sd
&& sd_degenerate(sd
)) {
7617 sched_domain_debug(sd
, cpu
);
7619 rq_attach_root(rq
, rd
);
7620 rcu_assign_pointer(rq
->sd
, sd
);
7623 /* cpus with isolated domains */
7624 static cpumask_var_t cpu_isolated_map
;
7626 /* Setup the mask of cpus configured for isolated domains */
7627 static int __init
isolated_cpu_setup(char *str
)
7629 cpulist_parse(str
, cpu_isolated_map
);
7633 __setup("isolcpus=", isolated_cpu_setup
);
7636 * init_sched_build_groups takes the cpumask we wish to span, and a pointer
7637 * to a function which identifies what group(along with sched group) a CPU
7638 * belongs to. The return value of group_fn must be a >= 0 and < nr_cpu_ids
7639 * (due to the fact that we keep track of groups covered with a struct cpumask).
7641 * init_sched_build_groups will build a circular linked list of the groups
7642 * covered by the given span, and will set each group's ->cpumask correctly,
7643 * and ->cpu_power to 0.
7646 init_sched_build_groups(const struct cpumask
*span
,
7647 const struct cpumask
*cpu_map
,
7648 int (*group_fn
)(int cpu
, const struct cpumask
*cpu_map
,
7649 struct sched_group
**sg
,
7650 struct cpumask
*tmpmask
),
7651 struct cpumask
*covered
, struct cpumask
*tmpmask
)
7653 struct sched_group
*first
= NULL
, *last
= NULL
;
7656 cpumask_clear(covered
);
7658 for_each_cpu(i
, span
) {
7659 struct sched_group
*sg
;
7660 int group
= group_fn(i
, cpu_map
, &sg
, tmpmask
);
7663 if (cpumask_test_cpu(i
, covered
))
7666 cpumask_clear(sched_group_cpus(sg
));
7667 sg
->__cpu_power
= 0;
7669 for_each_cpu(j
, span
) {
7670 if (group_fn(j
, cpu_map
, NULL
, tmpmask
) != group
)
7673 cpumask_set_cpu(j
, covered
);
7674 cpumask_set_cpu(j
, sched_group_cpus(sg
));
7685 #define SD_NODES_PER_DOMAIN 16
7690 * find_next_best_node - find the next node to include in a sched_domain
7691 * @node: node whose sched_domain we're building
7692 * @used_nodes: nodes already in the sched_domain
7694 * Find the next node to include in a given scheduling domain. Simply
7695 * finds the closest node not already in the @used_nodes map.
7697 * Should use nodemask_t.
7699 static int find_next_best_node(int node
, nodemask_t
*used_nodes
)
7701 int i
, n
, val
, min_val
, best_node
= 0;
7705 for (i
= 0; i
< nr_node_ids
; i
++) {
7706 /* Start at @node */
7707 n
= (node
+ i
) % nr_node_ids
;
7709 if (!nr_cpus_node(n
))
7712 /* Skip already used nodes */
7713 if (node_isset(n
, *used_nodes
))
7716 /* Simple min distance search */
7717 val
= node_distance(node
, n
);
7719 if (val
< min_val
) {
7725 node_set(best_node
, *used_nodes
);
7730 * sched_domain_node_span - get a cpumask for a node's sched_domain
7731 * @node: node whose cpumask we're constructing
7732 * @span: resulting cpumask
7734 * Given a node, construct a good cpumask for its sched_domain to span. It
7735 * should be one that prevents unnecessary balancing, but also spreads tasks
7738 static void sched_domain_node_span(int node
, struct cpumask
*span
)
7740 nodemask_t used_nodes
;
7743 cpumask_clear(span
);
7744 nodes_clear(used_nodes
);
7746 cpumask_or(span
, span
, cpumask_of_node(node
));
7747 node_set(node
, used_nodes
);
7749 for (i
= 1; i
< SD_NODES_PER_DOMAIN
; i
++) {
7750 int next_node
= find_next_best_node(node
, &used_nodes
);
7752 cpumask_or(span
, span
, cpumask_of_node(next_node
));
7755 #endif /* CONFIG_NUMA */
7757 int sched_smt_power_savings
= 0, sched_mc_power_savings
= 0;
7760 * The cpus mask in sched_group and sched_domain hangs off the end.
7761 * FIXME: use cpumask_var_t or dynamic percpu alloc to avoid wasting space
7762 * for nr_cpu_ids < CONFIG_NR_CPUS.
7764 struct static_sched_group
{
7765 struct sched_group sg
;
7766 DECLARE_BITMAP(cpus
, CONFIG_NR_CPUS
);
7769 struct static_sched_domain
{
7770 struct sched_domain sd
;
7771 DECLARE_BITMAP(span
, CONFIG_NR_CPUS
);
7775 * SMT sched-domains:
7777 #ifdef CONFIG_SCHED_SMT
7778 static DEFINE_PER_CPU(struct static_sched_domain
, cpu_domains
);
7779 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_cpus
);
7782 cpu_to_cpu_group(int cpu
, const struct cpumask
*cpu_map
,
7783 struct sched_group
**sg
, struct cpumask
*unused
)
7786 *sg
= &per_cpu(sched_group_cpus
, cpu
).sg
;
7789 #endif /* CONFIG_SCHED_SMT */
7792 * multi-core sched-domains:
7794 #ifdef CONFIG_SCHED_MC
7795 static DEFINE_PER_CPU(struct static_sched_domain
, core_domains
);
7796 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_core
);
7797 #endif /* CONFIG_SCHED_MC */
7799 #if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT)
7801 cpu_to_core_group(int cpu
, const struct cpumask
*cpu_map
,
7802 struct sched_group
**sg
, struct cpumask
*mask
)
7806 cpumask_and(mask
, topology_thread_cpumask(cpu
), cpu_map
);
7807 group
= cpumask_first(mask
);
7809 *sg
= &per_cpu(sched_group_core
, group
).sg
;
7812 #elif defined(CONFIG_SCHED_MC)
7814 cpu_to_core_group(int cpu
, const struct cpumask
*cpu_map
,
7815 struct sched_group
**sg
, struct cpumask
*unused
)
7818 *sg
= &per_cpu(sched_group_core
, cpu
).sg
;
7823 static DEFINE_PER_CPU(struct static_sched_domain
, phys_domains
);
7824 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_phys
);
7827 cpu_to_phys_group(int cpu
, const struct cpumask
*cpu_map
,
7828 struct sched_group
**sg
, struct cpumask
*mask
)
7831 #ifdef CONFIG_SCHED_MC
7832 cpumask_and(mask
, cpu_coregroup_mask(cpu
), cpu_map
);
7833 group
= cpumask_first(mask
);
7834 #elif defined(CONFIG_SCHED_SMT)
7835 cpumask_and(mask
, topology_thread_cpumask(cpu
), cpu_map
);
7836 group
= cpumask_first(mask
);
7841 *sg
= &per_cpu(sched_group_phys
, group
).sg
;
7847 * The init_sched_build_groups can't handle what we want to do with node
7848 * groups, so roll our own. Now each node has its own list of groups which
7849 * gets dynamically allocated.
7851 static DEFINE_PER_CPU(struct static_sched_domain
, node_domains
);
7852 static struct sched_group
***sched_group_nodes_bycpu
;
7854 static DEFINE_PER_CPU(struct static_sched_domain
, allnodes_domains
);
7855 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_allnodes
);
7857 static int cpu_to_allnodes_group(int cpu
, const struct cpumask
*cpu_map
,
7858 struct sched_group
**sg
,
7859 struct cpumask
*nodemask
)
7863 cpumask_and(nodemask
, cpumask_of_node(cpu_to_node(cpu
)), cpu_map
);
7864 group
= cpumask_first(nodemask
);
7867 *sg
= &per_cpu(sched_group_allnodes
, group
).sg
;
7871 static void init_numa_sched_groups_power(struct sched_group
*group_head
)
7873 struct sched_group
*sg
= group_head
;
7879 for_each_cpu(j
, sched_group_cpus(sg
)) {
7880 struct sched_domain
*sd
;
7882 sd
= &per_cpu(phys_domains
, j
).sd
;
7883 if (j
!= cpumask_first(sched_group_cpus(sd
->groups
))) {
7885 * Only add "power" once for each
7891 sg_inc_cpu_power(sg
, sd
->groups
->__cpu_power
);
7894 } while (sg
!= group_head
);
7896 #endif /* CONFIG_NUMA */
7899 /* Free memory allocated for various sched_group structures */
7900 static void free_sched_groups(const struct cpumask
*cpu_map
,
7901 struct cpumask
*nodemask
)
7905 for_each_cpu(cpu
, cpu_map
) {
7906 struct sched_group
**sched_group_nodes
7907 = sched_group_nodes_bycpu
[cpu
];
7909 if (!sched_group_nodes
)
7912 for (i
= 0; i
< nr_node_ids
; i
++) {
7913 struct sched_group
*oldsg
, *sg
= sched_group_nodes
[i
];
7915 cpumask_and(nodemask
, cpumask_of_node(i
), cpu_map
);
7916 if (cpumask_empty(nodemask
))
7926 if (oldsg
!= sched_group_nodes
[i
])
7929 kfree(sched_group_nodes
);
7930 sched_group_nodes_bycpu
[cpu
] = NULL
;
7933 #else /* !CONFIG_NUMA */
7934 static void free_sched_groups(const struct cpumask
*cpu_map
,
7935 struct cpumask
*nodemask
)
7938 #endif /* CONFIG_NUMA */
7941 * Initialize sched groups cpu_power.
7943 * cpu_power indicates the capacity of sched group, which is used while
7944 * distributing the load between different sched groups in a sched domain.
7945 * Typically cpu_power for all the groups in a sched domain will be same unless
7946 * there are asymmetries in the topology. If there are asymmetries, group
7947 * having more cpu_power will pickup more load compared to the group having
7950 * cpu_power will be a multiple of SCHED_LOAD_SCALE. This multiple represents
7951 * the maximum number of tasks a group can handle in the presence of other idle
7952 * or lightly loaded groups in the same sched domain.
7954 static void init_sched_groups_power(int cpu
, struct sched_domain
*sd
)
7956 struct sched_domain
*child
;
7957 struct sched_group
*group
;
7959 WARN_ON(!sd
|| !sd
->groups
);
7961 if (cpu
!= cpumask_first(sched_group_cpus(sd
->groups
)))
7966 sd
->groups
->__cpu_power
= 0;
7969 * For perf policy, if the groups in child domain share resources
7970 * (for example cores sharing some portions of the cache hierarchy
7971 * or SMT), then set this domain groups cpu_power such that each group
7972 * can handle only one task, when there are other idle groups in the
7973 * same sched domain.
7975 if (!child
|| (!(sd
->flags
& SD_POWERSAVINGS_BALANCE
) &&
7977 (SD_SHARE_CPUPOWER
| SD_SHARE_PKG_RESOURCES
)))) {
7978 sg_inc_cpu_power(sd
->groups
, SCHED_LOAD_SCALE
);
7983 * add cpu_power of each child group to this groups cpu_power
7985 group
= child
->groups
;
7987 sg_inc_cpu_power(sd
->groups
, group
->__cpu_power
);
7988 group
= group
->next
;
7989 } while (group
!= child
->groups
);
7993 * Initializers for schedule domains
7994 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
7997 #ifdef CONFIG_SCHED_DEBUG
7998 # define SD_INIT_NAME(sd, type) sd->name = #type
8000 # define SD_INIT_NAME(sd, type) do { } while (0)
8003 #define SD_INIT(sd, type) sd_init_##type(sd)
8005 #define SD_INIT_FUNC(type) \
8006 static noinline void sd_init_##type(struct sched_domain *sd) \
8008 memset(sd, 0, sizeof(*sd)); \
8009 *sd = SD_##type##_INIT; \
8010 sd->level = SD_LV_##type; \
8011 SD_INIT_NAME(sd, type); \
8016 SD_INIT_FUNC(ALLNODES
)
8019 #ifdef CONFIG_SCHED_SMT
8020 SD_INIT_FUNC(SIBLING
)
8022 #ifdef CONFIG_SCHED_MC
8026 static int default_relax_domain_level
= -1;
8028 static int __init
setup_relax_domain_level(char *str
)
8032 val
= simple_strtoul(str
, NULL
, 0);
8033 if (val
< SD_LV_MAX
)
8034 default_relax_domain_level
= val
;
8038 __setup("relax_domain_level=", setup_relax_domain_level
);
8040 static void set_domain_attribute(struct sched_domain
*sd
,
8041 struct sched_domain_attr
*attr
)
8045 if (!attr
|| attr
->relax_domain_level
< 0) {
8046 if (default_relax_domain_level
< 0)
8049 request
= default_relax_domain_level
;
8051 request
= attr
->relax_domain_level
;
8052 if (request
< sd
->level
) {
8053 /* turn off idle balance on this domain */
8054 sd
->flags
&= ~(SD_WAKE_IDLE
|SD_BALANCE_NEWIDLE
);
8056 /* turn on idle balance on this domain */
8057 sd
->flags
|= (SD_WAKE_IDLE_FAR
|SD_BALANCE_NEWIDLE
);
8062 * Build sched domains for a given set of cpus and attach the sched domains
8063 * to the individual cpus
8065 static int __build_sched_domains(const struct cpumask
*cpu_map
,
8066 struct sched_domain_attr
*attr
)
8068 int i
, err
= -ENOMEM
;
8069 struct root_domain
*rd
;
8070 cpumask_var_t nodemask
, this_sibling_map
, this_core_map
, send_covered
,
8073 cpumask_var_t domainspan
, covered
, notcovered
;
8074 struct sched_group
**sched_group_nodes
= NULL
;
8075 int sd_allnodes
= 0;
8077 if (!alloc_cpumask_var(&domainspan
, GFP_KERNEL
))
8079 if (!alloc_cpumask_var(&covered
, GFP_KERNEL
))
8080 goto free_domainspan
;
8081 if (!alloc_cpumask_var(¬covered
, GFP_KERNEL
))
8085 if (!alloc_cpumask_var(&nodemask
, GFP_KERNEL
))
8086 goto free_notcovered
;
8087 if (!alloc_cpumask_var(&this_sibling_map
, GFP_KERNEL
))
8089 if (!alloc_cpumask_var(&this_core_map
, GFP_KERNEL
))
8090 goto free_this_sibling_map
;
8091 if (!alloc_cpumask_var(&send_covered
, GFP_KERNEL
))
8092 goto free_this_core_map
;
8093 if (!alloc_cpumask_var(&tmpmask
, GFP_KERNEL
))
8094 goto free_send_covered
;
8098 * Allocate the per-node list of sched groups
8100 sched_group_nodes
= kcalloc(nr_node_ids
, sizeof(struct sched_group
*),
8102 if (!sched_group_nodes
) {
8103 printk(KERN_WARNING
"Can not alloc sched group node list\n");
8108 rd
= alloc_rootdomain();
8110 printk(KERN_WARNING
"Cannot alloc root domain\n");
8111 goto free_sched_groups
;
8115 sched_group_nodes_bycpu
[cpumask_first(cpu_map
)] = sched_group_nodes
;
8119 * Set up domains for cpus specified by the cpu_map.
8121 for_each_cpu(i
, cpu_map
) {
8122 struct sched_domain
*sd
= NULL
, *p
;
8124 cpumask_and(nodemask
, cpumask_of_node(cpu_to_node(i
)), cpu_map
);
8127 if (cpumask_weight(cpu_map
) >
8128 SD_NODES_PER_DOMAIN
*cpumask_weight(nodemask
)) {
8129 sd
= &per_cpu(allnodes_domains
, i
).sd
;
8130 SD_INIT(sd
, ALLNODES
);
8131 set_domain_attribute(sd
, attr
);
8132 cpumask_copy(sched_domain_span(sd
), cpu_map
);
8133 cpu_to_allnodes_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
8139 sd
= &per_cpu(node_domains
, i
).sd
;
8141 set_domain_attribute(sd
, attr
);
8142 sched_domain_node_span(cpu_to_node(i
), sched_domain_span(sd
));
8146 cpumask_and(sched_domain_span(sd
),
8147 sched_domain_span(sd
), cpu_map
);
8151 sd
= &per_cpu(phys_domains
, i
).sd
;
8153 set_domain_attribute(sd
, attr
);
8154 cpumask_copy(sched_domain_span(sd
), nodemask
);
8158 cpu_to_phys_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
8160 #ifdef CONFIG_SCHED_MC
8162 sd
= &per_cpu(core_domains
, i
).sd
;
8164 set_domain_attribute(sd
, attr
);
8165 cpumask_and(sched_domain_span(sd
), cpu_map
,
8166 cpu_coregroup_mask(i
));
8169 cpu_to_core_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
8172 #ifdef CONFIG_SCHED_SMT
8174 sd
= &per_cpu(cpu_domains
, i
).sd
;
8175 SD_INIT(sd
, SIBLING
);
8176 set_domain_attribute(sd
, attr
);
8177 cpumask_and(sched_domain_span(sd
),
8178 topology_thread_cpumask(i
), cpu_map
);
8181 cpu_to_cpu_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
8185 #ifdef CONFIG_SCHED_SMT
8186 /* Set up CPU (sibling) groups */
8187 for_each_cpu(i
, cpu_map
) {
8188 cpumask_and(this_sibling_map
,
8189 topology_thread_cpumask(i
), cpu_map
);
8190 if (i
!= cpumask_first(this_sibling_map
))
8193 init_sched_build_groups(this_sibling_map
, cpu_map
,
8195 send_covered
, tmpmask
);
8199 #ifdef CONFIG_SCHED_MC
8200 /* Set up multi-core groups */
8201 for_each_cpu(i
, cpu_map
) {
8202 cpumask_and(this_core_map
, cpu_coregroup_mask(i
), cpu_map
);
8203 if (i
!= cpumask_first(this_core_map
))
8206 init_sched_build_groups(this_core_map
, cpu_map
,
8208 send_covered
, tmpmask
);
8212 /* Set up physical groups */
8213 for (i
= 0; i
< nr_node_ids
; i
++) {
8214 cpumask_and(nodemask
, cpumask_of_node(i
), cpu_map
);
8215 if (cpumask_empty(nodemask
))
8218 init_sched_build_groups(nodemask
, cpu_map
,
8220 send_covered
, tmpmask
);
8224 /* Set up node groups */
8226 init_sched_build_groups(cpu_map
, cpu_map
,
8227 &cpu_to_allnodes_group
,
8228 send_covered
, tmpmask
);
8231 for (i
= 0; i
< nr_node_ids
; i
++) {
8232 /* Set up node groups */
8233 struct sched_group
*sg
, *prev
;
8236 cpumask_clear(covered
);
8237 cpumask_and(nodemask
, cpumask_of_node(i
), cpu_map
);
8238 if (cpumask_empty(nodemask
)) {
8239 sched_group_nodes
[i
] = NULL
;
8243 sched_domain_node_span(i
, domainspan
);
8244 cpumask_and(domainspan
, domainspan
, cpu_map
);
8246 sg
= kmalloc_node(sizeof(struct sched_group
) + cpumask_size(),
8249 printk(KERN_WARNING
"Can not alloc domain group for "
8253 sched_group_nodes
[i
] = sg
;
8254 for_each_cpu(j
, nodemask
) {
8255 struct sched_domain
*sd
;
8257 sd
= &per_cpu(node_domains
, j
).sd
;
8260 sg
->__cpu_power
= 0;
8261 cpumask_copy(sched_group_cpus(sg
), nodemask
);
8263 cpumask_or(covered
, covered
, nodemask
);
8266 for (j
= 0; j
< nr_node_ids
; j
++) {
8267 int n
= (i
+ j
) % nr_node_ids
;
8269 cpumask_complement(notcovered
, covered
);
8270 cpumask_and(tmpmask
, notcovered
, cpu_map
);
8271 cpumask_and(tmpmask
, tmpmask
, domainspan
);
8272 if (cpumask_empty(tmpmask
))
8275 cpumask_and(tmpmask
, tmpmask
, cpumask_of_node(n
));
8276 if (cpumask_empty(tmpmask
))
8279 sg
= kmalloc_node(sizeof(struct sched_group
) +
8284 "Can not alloc domain group for node %d\n", j
);
8287 sg
->__cpu_power
= 0;
8288 cpumask_copy(sched_group_cpus(sg
), tmpmask
);
8289 sg
->next
= prev
->next
;
8290 cpumask_or(covered
, covered
, tmpmask
);
8297 /* Calculate CPU power for physical packages and nodes */
8298 #ifdef CONFIG_SCHED_SMT
8299 for_each_cpu(i
, cpu_map
) {
8300 struct sched_domain
*sd
= &per_cpu(cpu_domains
, i
).sd
;
8302 init_sched_groups_power(i
, sd
);
8305 #ifdef CONFIG_SCHED_MC
8306 for_each_cpu(i
, cpu_map
) {
8307 struct sched_domain
*sd
= &per_cpu(core_domains
, i
).sd
;
8309 init_sched_groups_power(i
, sd
);
8313 for_each_cpu(i
, cpu_map
) {
8314 struct sched_domain
*sd
= &per_cpu(phys_domains
, i
).sd
;
8316 init_sched_groups_power(i
, sd
);
8320 for (i
= 0; i
< nr_node_ids
; i
++)
8321 init_numa_sched_groups_power(sched_group_nodes
[i
]);
8324 struct sched_group
*sg
;
8326 cpu_to_allnodes_group(cpumask_first(cpu_map
), cpu_map
, &sg
,
8328 init_numa_sched_groups_power(sg
);
8332 /* Attach the domains */
8333 for_each_cpu(i
, cpu_map
) {
8334 struct sched_domain
*sd
;
8335 #ifdef CONFIG_SCHED_SMT
8336 sd
= &per_cpu(cpu_domains
, i
).sd
;
8337 #elif defined(CONFIG_SCHED_MC)
8338 sd
= &per_cpu(core_domains
, i
).sd
;
8340 sd
= &per_cpu(phys_domains
, i
).sd
;
8342 cpu_attach_domain(sd
, rd
, i
);
8348 free_cpumask_var(tmpmask
);
8350 free_cpumask_var(send_covered
);
8352 free_cpumask_var(this_core_map
);
8353 free_this_sibling_map
:
8354 free_cpumask_var(this_sibling_map
);
8356 free_cpumask_var(nodemask
);
8359 free_cpumask_var(notcovered
);
8361 free_cpumask_var(covered
);
8363 free_cpumask_var(domainspan
);
8370 kfree(sched_group_nodes
);
8376 free_sched_groups(cpu_map
, tmpmask
);
8377 free_rootdomain(rd
);
8382 static int build_sched_domains(const struct cpumask
*cpu_map
)
8384 return __build_sched_domains(cpu_map
, NULL
);
8387 static struct cpumask
*doms_cur
; /* current sched domains */
8388 static int ndoms_cur
; /* number of sched domains in 'doms_cur' */
8389 static struct sched_domain_attr
*dattr_cur
;
8390 /* attribues of custom domains in 'doms_cur' */
8393 * Special case: If a kmalloc of a doms_cur partition (array of
8394 * cpumask) fails, then fallback to a single sched domain,
8395 * as determined by the single cpumask fallback_doms.
8397 static cpumask_var_t fallback_doms
;
8400 * arch_update_cpu_topology lets virtualized architectures update the
8401 * cpu core maps. It is supposed to return 1 if the topology changed
8402 * or 0 if it stayed the same.
8404 int __attribute__((weak
)) arch_update_cpu_topology(void)
8410 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
8411 * For now this just excludes isolated cpus, but could be used to
8412 * exclude other special cases in the future.
8414 static int arch_init_sched_domains(const struct cpumask
*cpu_map
)
8418 arch_update_cpu_topology();
8420 doms_cur
= kmalloc(cpumask_size(), GFP_KERNEL
);
8422 doms_cur
= fallback_doms
;
8423 cpumask_andnot(doms_cur
, cpu_map
, cpu_isolated_map
);
8425 err
= build_sched_domains(doms_cur
);
8426 register_sched_domain_sysctl();
8431 static void arch_destroy_sched_domains(const struct cpumask
*cpu_map
,
8432 struct cpumask
*tmpmask
)
8434 free_sched_groups(cpu_map
, tmpmask
);
8438 * Detach sched domains from a group of cpus specified in cpu_map
8439 * These cpus will now be attached to the NULL domain
8441 static void detach_destroy_domains(const struct cpumask
*cpu_map
)
8443 /* Save because hotplug lock held. */
8444 static DECLARE_BITMAP(tmpmask
, CONFIG_NR_CPUS
);
8447 for_each_cpu(i
, cpu_map
)
8448 cpu_attach_domain(NULL
, &def_root_domain
, i
);
8449 synchronize_sched();
8450 arch_destroy_sched_domains(cpu_map
, to_cpumask(tmpmask
));
8453 /* handle null as "default" */
8454 static int dattrs_equal(struct sched_domain_attr
*cur
, int idx_cur
,
8455 struct sched_domain_attr
*new, int idx_new
)
8457 struct sched_domain_attr tmp
;
8464 return !memcmp(cur
? (cur
+ idx_cur
) : &tmp
,
8465 new ? (new + idx_new
) : &tmp
,
8466 sizeof(struct sched_domain_attr
));
8470 * Partition sched domains as specified by the 'ndoms_new'
8471 * cpumasks in the array doms_new[] of cpumasks. This compares
8472 * doms_new[] to the current sched domain partitioning, doms_cur[].
8473 * It destroys each deleted domain and builds each new domain.
8475 * 'doms_new' is an array of cpumask's of length 'ndoms_new'.
8476 * The masks don't intersect (don't overlap.) We should setup one
8477 * sched domain for each mask. CPUs not in any of the cpumasks will
8478 * not be load balanced. If the same cpumask appears both in the
8479 * current 'doms_cur' domains and in the new 'doms_new', we can leave
8482 * The passed in 'doms_new' should be kmalloc'd. This routine takes
8483 * ownership of it and will kfree it when done with it. If the caller
8484 * failed the kmalloc call, then it can pass in doms_new == NULL &&
8485 * ndoms_new == 1, and partition_sched_domains() will fallback to
8486 * the single partition 'fallback_doms', it also forces the domains
8489 * If doms_new == NULL it will be replaced with cpu_online_mask.
8490 * ndoms_new == 0 is a special case for destroying existing domains,
8491 * and it will not create the default domain.
8493 * Call with hotplug lock held
8495 /* FIXME: Change to struct cpumask *doms_new[] */
8496 void partition_sched_domains(int ndoms_new
, struct cpumask
*doms_new
,
8497 struct sched_domain_attr
*dattr_new
)
8502 mutex_lock(&sched_domains_mutex
);
8504 /* always unregister in case we don't destroy any domains */
8505 unregister_sched_domain_sysctl();
8507 /* Let architecture update cpu core mappings. */
8508 new_topology
= arch_update_cpu_topology();
8510 n
= doms_new
? ndoms_new
: 0;
8512 /* Destroy deleted domains */
8513 for (i
= 0; i
< ndoms_cur
; i
++) {
8514 for (j
= 0; j
< n
&& !new_topology
; j
++) {
8515 if (cpumask_equal(&doms_cur
[i
], &doms_new
[j
])
8516 && dattrs_equal(dattr_cur
, i
, dattr_new
, j
))
8519 /* no match - a current sched domain not in new doms_new[] */
8520 detach_destroy_domains(doms_cur
+ i
);
8525 if (doms_new
== NULL
) {
8527 doms_new
= fallback_doms
;
8528 cpumask_andnot(&doms_new
[0], cpu_online_mask
, cpu_isolated_map
);
8529 WARN_ON_ONCE(dattr_new
);
8532 /* Build new domains */
8533 for (i
= 0; i
< ndoms_new
; i
++) {
8534 for (j
= 0; j
< ndoms_cur
&& !new_topology
; j
++) {
8535 if (cpumask_equal(&doms_new
[i
], &doms_cur
[j
])
8536 && dattrs_equal(dattr_new
, i
, dattr_cur
, j
))
8539 /* no match - add a new doms_new */
8540 __build_sched_domains(doms_new
+ i
,
8541 dattr_new
? dattr_new
+ i
: NULL
);
8546 /* Remember the new sched domains */
8547 if (doms_cur
!= fallback_doms
)
8549 kfree(dattr_cur
); /* kfree(NULL) is safe */
8550 doms_cur
= doms_new
;
8551 dattr_cur
= dattr_new
;
8552 ndoms_cur
= ndoms_new
;
8554 register_sched_domain_sysctl();
8556 mutex_unlock(&sched_domains_mutex
);
8559 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
8560 static void arch_reinit_sched_domains(void)
8564 /* Destroy domains first to force the rebuild */
8565 partition_sched_domains(0, NULL
, NULL
);
8567 rebuild_sched_domains();
8571 static ssize_t
sched_power_savings_store(const char *buf
, size_t count
, int smt
)
8573 unsigned int level
= 0;
8575 if (sscanf(buf
, "%u", &level
) != 1)
8579 * level is always be positive so don't check for
8580 * level < POWERSAVINGS_BALANCE_NONE which is 0
8581 * What happens on 0 or 1 byte write,
8582 * need to check for count as well?
8585 if (level
>= MAX_POWERSAVINGS_BALANCE_LEVELS
)
8589 sched_smt_power_savings
= level
;
8591 sched_mc_power_savings
= level
;
8593 arch_reinit_sched_domains();
8598 #ifdef CONFIG_SCHED_MC
8599 static ssize_t
sched_mc_power_savings_show(struct sysdev_class
*class,
8602 return sprintf(page
, "%u\n", sched_mc_power_savings
);
8604 static ssize_t
sched_mc_power_savings_store(struct sysdev_class
*class,
8605 const char *buf
, size_t count
)
8607 return sched_power_savings_store(buf
, count
, 0);
8609 static SYSDEV_CLASS_ATTR(sched_mc_power_savings
, 0644,
8610 sched_mc_power_savings_show
,
8611 sched_mc_power_savings_store
);
8614 #ifdef CONFIG_SCHED_SMT
8615 static ssize_t
sched_smt_power_savings_show(struct sysdev_class
*dev
,
8618 return sprintf(page
, "%u\n", sched_smt_power_savings
);
8620 static ssize_t
sched_smt_power_savings_store(struct sysdev_class
*dev
,
8621 const char *buf
, size_t count
)
8623 return sched_power_savings_store(buf
, count
, 1);
8625 static SYSDEV_CLASS_ATTR(sched_smt_power_savings
, 0644,
8626 sched_smt_power_savings_show
,
8627 sched_smt_power_savings_store
);
8630 int __init
sched_create_sysfs_power_savings_entries(struct sysdev_class
*cls
)
8634 #ifdef CONFIG_SCHED_SMT
8636 err
= sysfs_create_file(&cls
->kset
.kobj
,
8637 &attr_sched_smt_power_savings
.attr
);
8639 #ifdef CONFIG_SCHED_MC
8640 if (!err
&& mc_capable())
8641 err
= sysfs_create_file(&cls
->kset
.kobj
,
8642 &attr_sched_mc_power_savings
.attr
);
8646 #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
8648 #ifndef CONFIG_CPUSETS
8650 * Add online and remove offline CPUs from the scheduler domains.
8651 * When cpusets are enabled they take over this function.
8653 static int update_sched_domains(struct notifier_block
*nfb
,
8654 unsigned long action
, void *hcpu
)
8658 case CPU_ONLINE_FROZEN
:
8660 case CPU_DEAD_FROZEN
:
8661 partition_sched_domains(1, NULL
, NULL
);
8670 static int update_runtime(struct notifier_block
*nfb
,
8671 unsigned long action
, void *hcpu
)
8673 int cpu
= (int)(long)hcpu
;
8676 case CPU_DOWN_PREPARE
:
8677 case CPU_DOWN_PREPARE_FROZEN
:
8678 disable_runtime(cpu_rq(cpu
));
8681 case CPU_DOWN_FAILED
:
8682 case CPU_DOWN_FAILED_FROZEN
:
8684 case CPU_ONLINE_FROZEN
:
8685 enable_runtime(cpu_rq(cpu
));
8693 void __init
sched_init_smp(void)
8695 cpumask_var_t non_isolated_cpus
;
8697 alloc_cpumask_var(&non_isolated_cpus
, GFP_KERNEL
);
8699 #if defined(CONFIG_NUMA)
8700 sched_group_nodes_bycpu
= kzalloc(nr_cpu_ids
* sizeof(void **),
8702 BUG_ON(sched_group_nodes_bycpu
== NULL
);
8705 mutex_lock(&sched_domains_mutex
);
8706 arch_init_sched_domains(cpu_online_mask
);
8707 cpumask_andnot(non_isolated_cpus
, cpu_possible_mask
, cpu_isolated_map
);
8708 if (cpumask_empty(non_isolated_cpus
))
8709 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus
);
8710 mutex_unlock(&sched_domains_mutex
);
8713 #ifndef CONFIG_CPUSETS
8714 /* XXX: Theoretical race here - CPU may be hotplugged now */
8715 hotcpu_notifier(update_sched_domains
, 0);
8718 /* RT runtime code needs to handle some hotplug events */
8719 hotcpu_notifier(update_runtime
, 0);
8723 /* Move init over to a non-isolated CPU */
8724 if (set_cpus_allowed_ptr(current
, non_isolated_cpus
) < 0)
8726 sched_init_granularity();
8727 free_cpumask_var(non_isolated_cpus
);
8729 alloc_cpumask_var(&fallback_doms
, GFP_KERNEL
);
8730 init_sched_rt_class();
8733 void __init
sched_init_smp(void)
8735 sched_init_granularity();
8737 #endif /* CONFIG_SMP */
8739 const_debug
unsigned int sysctl_timer_migration
= 1;
8741 int in_sched_functions(unsigned long addr
)
8743 return in_lock_functions(addr
) ||
8744 (addr
>= (unsigned long)__sched_text_start
8745 && addr
< (unsigned long)__sched_text_end
);
8748 static void init_cfs_rq(struct cfs_rq
*cfs_rq
, struct rq
*rq
)
8750 cfs_rq
->tasks_timeline
= RB_ROOT
;
8751 INIT_LIST_HEAD(&cfs_rq
->tasks
);
8752 #ifdef CONFIG_FAIR_GROUP_SCHED
8755 cfs_rq
->min_vruntime
= (u64
)(-(1LL << 20));
8758 static void init_rt_rq(struct rt_rq
*rt_rq
, struct rq
*rq
)
8760 struct rt_prio_array
*array
;
8763 array
= &rt_rq
->active
;
8764 for (i
= 0; i
< MAX_RT_PRIO
; i
++) {
8765 INIT_LIST_HEAD(array
->queue
+ i
);
8766 __clear_bit(i
, array
->bitmap
);
8768 /* delimiter for bitsearch: */
8769 __set_bit(MAX_RT_PRIO
, array
->bitmap
);
8771 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
8772 rt_rq
->highest_prio
.curr
= MAX_RT_PRIO
;
8774 rt_rq
->highest_prio
.next
= MAX_RT_PRIO
;
8778 rt_rq
->rt_nr_migratory
= 0;
8779 rt_rq
->overloaded
= 0;
8780 plist_head_init(&rq
->rt
.pushable_tasks
, &rq
->lock
);
8784 rt_rq
->rt_throttled
= 0;
8785 rt_rq
->rt_runtime
= 0;
8786 spin_lock_init(&rt_rq
->rt_runtime_lock
);
8788 #ifdef CONFIG_RT_GROUP_SCHED
8789 rt_rq
->rt_nr_boosted
= 0;
8794 #ifdef CONFIG_FAIR_GROUP_SCHED
8795 static void init_tg_cfs_entry(struct task_group
*tg
, struct cfs_rq
*cfs_rq
,
8796 struct sched_entity
*se
, int cpu
, int add
,
8797 struct sched_entity
*parent
)
8799 struct rq
*rq
= cpu_rq(cpu
);
8800 tg
->cfs_rq
[cpu
] = cfs_rq
;
8801 init_cfs_rq(cfs_rq
, rq
);
8804 list_add(&cfs_rq
->leaf_cfs_rq_list
, &rq
->leaf_cfs_rq_list
);
8807 /* se could be NULL for init_task_group */
8812 se
->cfs_rq
= &rq
->cfs
;
8814 se
->cfs_rq
= parent
->my_q
;
8817 se
->load
.weight
= tg
->shares
;
8818 se
->load
.inv_weight
= 0;
8819 se
->parent
= parent
;
8823 #ifdef CONFIG_RT_GROUP_SCHED
8824 static void init_tg_rt_entry(struct task_group
*tg
, struct rt_rq
*rt_rq
,
8825 struct sched_rt_entity
*rt_se
, int cpu
, int add
,
8826 struct sched_rt_entity
*parent
)
8828 struct rq
*rq
= cpu_rq(cpu
);
8830 tg
->rt_rq
[cpu
] = rt_rq
;
8831 init_rt_rq(rt_rq
, rq
);
8833 rt_rq
->rt_se
= rt_se
;
8834 rt_rq
->rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
8836 list_add(&rt_rq
->leaf_rt_rq_list
, &rq
->leaf_rt_rq_list
);
8838 tg
->rt_se
[cpu
] = rt_se
;
8843 rt_se
->rt_rq
= &rq
->rt
;
8845 rt_se
->rt_rq
= parent
->my_q
;
8847 rt_se
->my_q
= rt_rq
;
8848 rt_se
->parent
= parent
;
8849 INIT_LIST_HEAD(&rt_se
->run_list
);
8853 void __init
sched_init(void)
8856 unsigned long alloc_size
= 0, ptr
;
8858 #ifdef CONFIG_FAIR_GROUP_SCHED
8859 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
8861 #ifdef CONFIG_RT_GROUP_SCHED
8862 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
8864 #ifdef CONFIG_USER_SCHED
8867 #ifdef CONFIG_CPUMASK_OFFSTACK
8868 alloc_size
+= num_possible_cpus() * cpumask_size();
8871 * As sched_init() is called before page_alloc is setup,
8872 * we use alloc_bootmem().
8875 ptr
= (unsigned long)alloc_bootmem(alloc_size
);
8877 #ifdef CONFIG_FAIR_GROUP_SCHED
8878 init_task_group
.se
= (struct sched_entity
**)ptr
;
8879 ptr
+= nr_cpu_ids
* sizeof(void **);
8881 init_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
8882 ptr
+= nr_cpu_ids
* sizeof(void **);
8884 #ifdef CONFIG_USER_SCHED
8885 root_task_group
.se
= (struct sched_entity
**)ptr
;
8886 ptr
+= nr_cpu_ids
* sizeof(void **);
8888 root_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
8889 ptr
+= nr_cpu_ids
* sizeof(void **);
8890 #endif /* CONFIG_USER_SCHED */
8891 #endif /* CONFIG_FAIR_GROUP_SCHED */
8892 #ifdef CONFIG_RT_GROUP_SCHED
8893 init_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
8894 ptr
+= nr_cpu_ids
* sizeof(void **);
8896 init_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
8897 ptr
+= nr_cpu_ids
* sizeof(void **);
8899 #ifdef CONFIG_USER_SCHED
8900 root_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
8901 ptr
+= nr_cpu_ids
* sizeof(void **);
8903 root_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
8904 ptr
+= nr_cpu_ids
* sizeof(void **);
8905 #endif /* CONFIG_USER_SCHED */
8906 #endif /* CONFIG_RT_GROUP_SCHED */
8907 #ifdef CONFIG_CPUMASK_OFFSTACK
8908 for_each_possible_cpu(i
) {
8909 per_cpu(load_balance_tmpmask
, i
) = (void *)ptr
;
8910 ptr
+= cpumask_size();
8912 #endif /* CONFIG_CPUMASK_OFFSTACK */
8916 init_defrootdomain();
8919 init_rt_bandwidth(&def_rt_bandwidth
,
8920 global_rt_period(), global_rt_runtime());
8922 #ifdef CONFIG_RT_GROUP_SCHED
8923 init_rt_bandwidth(&init_task_group
.rt_bandwidth
,
8924 global_rt_period(), global_rt_runtime());
8925 #ifdef CONFIG_USER_SCHED
8926 init_rt_bandwidth(&root_task_group
.rt_bandwidth
,
8927 global_rt_period(), RUNTIME_INF
);
8928 #endif /* CONFIG_USER_SCHED */
8929 #endif /* CONFIG_RT_GROUP_SCHED */
8931 #ifdef CONFIG_GROUP_SCHED
8932 list_add(&init_task_group
.list
, &task_groups
);
8933 INIT_LIST_HEAD(&init_task_group
.children
);
8935 #ifdef CONFIG_USER_SCHED
8936 INIT_LIST_HEAD(&root_task_group
.children
);
8937 init_task_group
.parent
= &root_task_group
;
8938 list_add(&init_task_group
.siblings
, &root_task_group
.children
);
8939 #endif /* CONFIG_USER_SCHED */
8940 #endif /* CONFIG_GROUP_SCHED */
8942 for_each_possible_cpu(i
) {
8946 spin_lock_init(&rq
->lock
);
8948 init_cfs_rq(&rq
->cfs
, rq
);
8949 init_rt_rq(&rq
->rt
, rq
);
8950 #ifdef CONFIG_FAIR_GROUP_SCHED
8951 init_task_group
.shares
= init_task_group_load
;
8952 INIT_LIST_HEAD(&rq
->leaf_cfs_rq_list
);
8953 #ifdef CONFIG_CGROUP_SCHED
8955 * How much cpu bandwidth does init_task_group get?
8957 * In case of task-groups formed thr' the cgroup filesystem, it
8958 * gets 100% of the cpu resources in the system. This overall
8959 * system cpu resource is divided among the tasks of
8960 * init_task_group and its child task-groups in a fair manner,
8961 * based on each entity's (task or task-group's) weight
8962 * (se->load.weight).
8964 * In other words, if init_task_group has 10 tasks of weight
8965 * 1024) and two child groups A0 and A1 (of weight 1024 each),
8966 * then A0's share of the cpu resource is:
8968 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
8970 * We achieve this by letting init_task_group's tasks sit
8971 * directly in rq->cfs (i.e init_task_group->se[] = NULL).
8973 init_tg_cfs_entry(&init_task_group
, &rq
->cfs
, NULL
, i
, 1, NULL
);
8974 #elif defined CONFIG_USER_SCHED
8975 root_task_group
.shares
= NICE_0_LOAD
;
8976 init_tg_cfs_entry(&root_task_group
, &rq
->cfs
, NULL
, i
, 0, NULL
);
8978 * In case of task-groups formed thr' the user id of tasks,
8979 * init_task_group represents tasks belonging to root user.
8980 * Hence it forms a sibling of all subsequent groups formed.
8981 * In this case, init_task_group gets only a fraction of overall
8982 * system cpu resource, based on the weight assigned to root
8983 * user's cpu share (INIT_TASK_GROUP_LOAD). This is accomplished
8984 * by letting tasks of init_task_group sit in a separate cfs_rq
8985 * (init_cfs_rq) and having one entity represent this group of
8986 * tasks in rq->cfs (i.e init_task_group->se[] != NULL).
8988 init_tg_cfs_entry(&init_task_group
,
8989 &per_cpu(init_cfs_rq
, i
),
8990 &per_cpu(init_sched_entity
, i
), i
, 1,
8991 root_task_group
.se
[i
]);
8994 #endif /* CONFIG_FAIR_GROUP_SCHED */
8996 rq
->rt
.rt_runtime
= def_rt_bandwidth
.rt_runtime
;
8997 #ifdef CONFIG_RT_GROUP_SCHED
8998 INIT_LIST_HEAD(&rq
->leaf_rt_rq_list
);
8999 #ifdef CONFIG_CGROUP_SCHED
9000 init_tg_rt_entry(&init_task_group
, &rq
->rt
, NULL
, i
, 1, NULL
);
9001 #elif defined CONFIG_USER_SCHED
9002 init_tg_rt_entry(&root_task_group
, &rq
->rt
, NULL
, i
, 0, NULL
);
9003 init_tg_rt_entry(&init_task_group
,
9004 &per_cpu(init_rt_rq
, i
),
9005 &per_cpu(init_sched_rt_entity
, i
), i
, 1,
9006 root_task_group
.rt_se
[i
]);
9010 for (j
= 0; j
< CPU_LOAD_IDX_MAX
; j
++)
9011 rq
->cpu_load
[j
] = 0;
9015 rq
->active_balance
= 0;
9016 rq
->next_balance
= jiffies
;
9020 rq
->migration_thread
= NULL
;
9021 INIT_LIST_HEAD(&rq
->migration_queue
);
9022 rq_attach_root(rq
, &def_root_domain
);
9025 atomic_set(&rq
->nr_iowait
, 0);
9028 set_load_weight(&init_task
);
9030 #ifdef CONFIG_PREEMPT_NOTIFIERS
9031 INIT_HLIST_HEAD(&init_task
.preempt_notifiers
);
9035 open_softirq(SCHED_SOFTIRQ
, run_rebalance_domains
);
9038 #ifdef CONFIG_RT_MUTEXES
9039 plist_head_init(&init_task
.pi_waiters
, &init_task
.pi_lock
);
9043 * The boot idle thread does lazy MMU switching as well:
9045 atomic_inc(&init_mm
.mm_count
);
9046 enter_lazy_tlb(&init_mm
, current
);
9049 * Make us the idle thread. Technically, schedule() should not be
9050 * called from this thread, however somewhere below it might be,
9051 * but because we are the idle thread, we just pick up running again
9052 * when this runqueue becomes "idle".
9054 init_idle(current
, smp_processor_id());
9056 * During early bootup we pretend to be a normal task:
9058 current
->sched_class
= &fair_sched_class
;
9060 /* Allocate the nohz_cpu_mask if CONFIG_CPUMASK_OFFSTACK */
9061 alloc_bootmem_cpumask_var(&nohz_cpu_mask
);
9064 alloc_bootmem_cpumask_var(&nohz
.cpu_mask
);
9066 alloc_bootmem_cpumask_var(&cpu_isolated_map
);
9069 scheduler_running
= 1;
9072 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
9073 void __might_sleep(char *file
, int line
)
9076 static unsigned long prev_jiffy
; /* ratelimiting */
9078 if ((!in_atomic() && !irqs_disabled()) ||
9079 system_state
!= SYSTEM_RUNNING
|| oops_in_progress
)
9081 if (time_before(jiffies
, prev_jiffy
+ HZ
) && prev_jiffy
)
9083 prev_jiffy
= jiffies
;
9086 "BUG: sleeping function called from invalid context at %s:%d\n",
9089 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
9090 in_atomic(), irqs_disabled(),
9091 current
->pid
, current
->comm
);
9093 debug_show_held_locks(current
);
9094 if (irqs_disabled())
9095 print_irqtrace_events(current
);
9099 EXPORT_SYMBOL(__might_sleep
);
9102 #ifdef CONFIG_MAGIC_SYSRQ
9103 static void normalize_task(struct rq
*rq
, struct task_struct
*p
)
9107 update_rq_clock(rq
);
9108 on_rq
= p
->se
.on_rq
;
9110 deactivate_task(rq
, p
, 0);
9111 __setscheduler(rq
, p
, SCHED_NORMAL
, 0);
9113 activate_task(rq
, p
, 0);
9114 resched_task(rq
->curr
);
9118 void normalize_rt_tasks(void)
9120 struct task_struct
*g
, *p
;
9121 unsigned long flags
;
9124 read_lock_irqsave(&tasklist_lock
, flags
);
9125 do_each_thread(g
, p
) {
9127 * Only normalize user tasks:
9132 p
->se
.exec_start
= 0;
9133 #ifdef CONFIG_SCHEDSTATS
9134 p
->se
.wait_start
= 0;
9135 p
->se
.sleep_start
= 0;
9136 p
->se
.block_start
= 0;
9141 * Renice negative nice level userspace
9144 if (TASK_NICE(p
) < 0 && p
->mm
)
9145 set_user_nice(p
, 0);
9149 spin_lock(&p
->pi_lock
);
9150 rq
= __task_rq_lock(p
);
9152 normalize_task(rq
, p
);
9154 __task_rq_unlock(rq
);
9155 spin_unlock(&p
->pi_lock
);
9156 } while_each_thread(g
, p
);
9158 read_unlock_irqrestore(&tasklist_lock
, flags
);
9161 #endif /* CONFIG_MAGIC_SYSRQ */
9165 * These functions are only useful for the IA64 MCA handling.
9167 * They can only be called when the whole system has been
9168 * stopped - every CPU needs to be quiescent, and no scheduling
9169 * activity can take place. Using them for anything else would
9170 * be a serious bug, and as a result, they aren't even visible
9171 * under any other configuration.
9175 * curr_task - return the current task for a given cpu.
9176 * @cpu: the processor in question.
9178 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
9180 struct task_struct
*curr_task(int cpu
)
9182 return cpu_curr(cpu
);
9186 * set_curr_task - set the current task for a given cpu.
9187 * @cpu: the processor in question.
9188 * @p: the task pointer to set.
9190 * Description: This function must only be used when non-maskable interrupts
9191 * are serviced on a separate stack. It allows the architecture to switch the
9192 * notion of the current task on a cpu in a non-blocking manner. This function
9193 * must be called with all CPU's synchronized, and interrupts disabled, the
9194 * and caller must save the original value of the current task (see
9195 * curr_task() above) and restore that value before reenabling interrupts and
9196 * re-starting the system.
9198 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
9200 void set_curr_task(int cpu
, struct task_struct
*p
)
9207 #ifdef CONFIG_FAIR_GROUP_SCHED
9208 static void free_fair_sched_group(struct task_group
*tg
)
9212 for_each_possible_cpu(i
) {
9214 kfree(tg
->cfs_rq
[i
]);
9224 int alloc_fair_sched_group(struct task_group
*tg
, struct task_group
*parent
)
9226 struct cfs_rq
*cfs_rq
;
9227 struct sched_entity
*se
;
9231 tg
->cfs_rq
= kzalloc(sizeof(cfs_rq
) * nr_cpu_ids
, GFP_KERNEL
);
9234 tg
->se
= kzalloc(sizeof(se
) * nr_cpu_ids
, GFP_KERNEL
);
9238 tg
->shares
= NICE_0_LOAD
;
9240 for_each_possible_cpu(i
) {
9243 cfs_rq
= kzalloc_node(sizeof(struct cfs_rq
),
9244 GFP_KERNEL
, cpu_to_node(i
));
9248 se
= kzalloc_node(sizeof(struct sched_entity
),
9249 GFP_KERNEL
, cpu_to_node(i
));
9253 init_tg_cfs_entry(tg
, cfs_rq
, se
, i
, 0, parent
->se
[i
]);
9262 static inline void register_fair_sched_group(struct task_group
*tg
, int cpu
)
9264 list_add_rcu(&tg
->cfs_rq
[cpu
]->leaf_cfs_rq_list
,
9265 &cpu_rq(cpu
)->leaf_cfs_rq_list
);
9268 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
9270 list_del_rcu(&tg
->cfs_rq
[cpu
]->leaf_cfs_rq_list
);
9272 #else /* !CONFG_FAIR_GROUP_SCHED */
9273 static inline void free_fair_sched_group(struct task_group
*tg
)
9278 int alloc_fair_sched_group(struct task_group
*tg
, struct task_group
*parent
)
9283 static inline void register_fair_sched_group(struct task_group
*tg
, int cpu
)
9287 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
9290 #endif /* CONFIG_FAIR_GROUP_SCHED */
9292 #ifdef CONFIG_RT_GROUP_SCHED
9293 static void free_rt_sched_group(struct task_group
*tg
)
9297 destroy_rt_bandwidth(&tg
->rt_bandwidth
);
9299 for_each_possible_cpu(i
) {
9301 kfree(tg
->rt_rq
[i
]);
9303 kfree(tg
->rt_se
[i
]);
9311 int alloc_rt_sched_group(struct task_group
*tg
, struct task_group
*parent
)
9313 struct rt_rq
*rt_rq
;
9314 struct sched_rt_entity
*rt_se
;
9318 tg
->rt_rq
= kzalloc(sizeof(rt_rq
) * nr_cpu_ids
, GFP_KERNEL
);
9321 tg
->rt_se
= kzalloc(sizeof(rt_se
) * nr_cpu_ids
, GFP_KERNEL
);
9325 init_rt_bandwidth(&tg
->rt_bandwidth
,
9326 ktime_to_ns(def_rt_bandwidth
.rt_period
), 0);
9328 for_each_possible_cpu(i
) {
9331 rt_rq
= kzalloc_node(sizeof(struct rt_rq
),
9332 GFP_KERNEL
, cpu_to_node(i
));
9336 rt_se
= kzalloc_node(sizeof(struct sched_rt_entity
),
9337 GFP_KERNEL
, cpu_to_node(i
));
9341 init_tg_rt_entry(tg
, rt_rq
, rt_se
, i
, 0, parent
->rt_se
[i
]);
9350 static inline void register_rt_sched_group(struct task_group
*tg
, int cpu
)
9352 list_add_rcu(&tg
->rt_rq
[cpu
]->leaf_rt_rq_list
,
9353 &cpu_rq(cpu
)->leaf_rt_rq_list
);
9356 static inline void unregister_rt_sched_group(struct task_group
*tg
, int cpu
)
9358 list_del_rcu(&tg
->rt_rq
[cpu
]->leaf_rt_rq_list
);
9360 #else /* !CONFIG_RT_GROUP_SCHED */
9361 static inline void free_rt_sched_group(struct task_group
*tg
)
9366 int alloc_rt_sched_group(struct task_group
*tg
, struct task_group
*parent
)
9371 static inline void register_rt_sched_group(struct task_group
*tg
, int cpu
)
9375 static inline void unregister_rt_sched_group(struct task_group
*tg
, int cpu
)
9378 #endif /* CONFIG_RT_GROUP_SCHED */
9380 #ifdef CONFIG_GROUP_SCHED
9381 static void free_sched_group(struct task_group
*tg
)
9383 free_fair_sched_group(tg
);
9384 free_rt_sched_group(tg
);
9388 /* allocate runqueue etc for a new task group */
9389 struct task_group
*sched_create_group(struct task_group
*parent
)
9391 struct task_group
*tg
;
9392 unsigned long flags
;
9395 tg
= kzalloc(sizeof(*tg
), GFP_KERNEL
);
9397 return ERR_PTR(-ENOMEM
);
9399 if (!alloc_fair_sched_group(tg
, parent
))
9402 if (!alloc_rt_sched_group(tg
, parent
))
9405 spin_lock_irqsave(&task_group_lock
, flags
);
9406 for_each_possible_cpu(i
) {
9407 register_fair_sched_group(tg
, i
);
9408 register_rt_sched_group(tg
, i
);
9410 list_add_rcu(&tg
->list
, &task_groups
);
9412 WARN_ON(!parent
); /* root should already exist */
9414 tg
->parent
= parent
;
9415 INIT_LIST_HEAD(&tg
->children
);
9416 list_add_rcu(&tg
->siblings
, &parent
->children
);
9417 spin_unlock_irqrestore(&task_group_lock
, flags
);
9422 free_sched_group(tg
);
9423 return ERR_PTR(-ENOMEM
);
9426 /* rcu callback to free various structures associated with a task group */
9427 static void free_sched_group_rcu(struct rcu_head
*rhp
)
9429 /* now it should be safe to free those cfs_rqs */
9430 free_sched_group(container_of(rhp
, struct task_group
, rcu
));
9433 /* Destroy runqueue etc associated with a task group */
9434 void sched_destroy_group(struct task_group
*tg
)
9436 unsigned long flags
;
9439 spin_lock_irqsave(&task_group_lock
, flags
);
9440 for_each_possible_cpu(i
) {
9441 unregister_fair_sched_group(tg
, i
);
9442 unregister_rt_sched_group(tg
, i
);
9444 list_del_rcu(&tg
->list
);
9445 list_del_rcu(&tg
->siblings
);
9446 spin_unlock_irqrestore(&task_group_lock
, flags
);
9448 /* wait for possible concurrent references to cfs_rqs complete */
9449 call_rcu(&tg
->rcu
, free_sched_group_rcu
);
9452 /* change task's runqueue when it moves between groups.
9453 * The caller of this function should have put the task in its new group
9454 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
9455 * reflect its new group.
9457 void sched_move_task(struct task_struct
*tsk
)
9460 unsigned long flags
;
9463 rq
= task_rq_lock(tsk
, &flags
);
9465 update_rq_clock(rq
);
9467 running
= task_current(rq
, tsk
);
9468 on_rq
= tsk
->se
.on_rq
;
9471 dequeue_task(rq
, tsk
, 0);
9472 if (unlikely(running
))
9473 tsk
->sched_class
->put_prev_task(rq
, tsk
);
9475 set_task_rq(tsk
, task_cpu(tsk
));
9477 #ifdef CONFIG_FAIR_GROUP_SCHED
9478 if (tsk
->sched_class
->moved_group
)
9479 tsk
->sched_class
->moved_group(tsk
);
9482 if (unlikely(running
))
9483 tsk
->sched_class
->set_curr_task(rq
);
9485 enqueue_task(rq
, tsk
, 0);
9487 task_rq_unlock(rq
, &flags
);
9489 #endif /* CONFIG_GROUP_SCHED */
9491 #ifdef CONFIG_FAIR_GROUP_SCHED
9492 static void __set_se_shares(struct sched_entity
*se
, unsigned long shares
)
9494 struct cfs_rq
*cfs_rq
= se
->cfs_rq
;
9499 dequeue_entity(cfs_rq
, se
, 0);
9501 se
->load
.weight
= shares
;
9502 se
->load
.inv_weight
= 0;
9505 enqueue_entity(cfs_rq
, se
, 0);
9508 static void set_se_shares(struct sched_entity
*se
, unsigned long shares
)
9510 struct cfs_rq
*cfs_rq
= se
->cfs_rq
;
9511 struct rq
*rq
= cfs_rq
->rq
;
9512 unsigned long flags
;
9514 spin_lock_irqsave(&rq
->lock
, flags
);
9515 __set_se_shares(se
, shares
);
9516 spin_unlock_irqrestore(&rq
->lock
, flags
);
9519 static DEFINE_MUTEX(shares_mutex
);
9521 int sched_group_set_shares(struct task_group
*tg
, unsigned long shares
)
9524 unsigned long flags
;
9527 * We can't change the weight of the root cgroup.
9532 if (shares
< MIN_SHARES
)
9533 shares
= MIN_SHARES
;
9534 else if (shares
> MAX_SHARES
)
9535 shares
= MAX_SHARES
;
9537 mutex_lock(&shares_mutex
);
9538 if (tg
->shares
== shares
)
9541 spin_lock_irqsave(&task_group_lock
, flags
);
9542 for_each_possible_cpu(i
)
9543 unregister_fair_sched_group(tg
, i
);
9544 list_del_rcu(&tg
->siblings
);
9545 spin_unlock_irqrestore(&task_group_lock
, flags
);
9547 /* wait for any ongoing reference to this group to finish */
9548 synchronize_sched();
9551 * Now we are free to modify the group's share on each cpu
9552 * w/o tripping rebalance_share or load_balance_fair.
9554 tg
->shares
= shares
;
9555 for_each_possible_cpu(i
) {
9559 cfs_rq_set_shares(tg
->cfs_rq
[i
], 0);
9560 set_se_shares(tg
->se
[i
], shares
);
9564 * Enable load balance activity on this group, by inserting it back on
9565 * each cpu's rq->leaf_cfs_rq_list.
9567 spin_lock_irqsave(&task_group_lock
, flags
);
9568 for_each_possible_cpu(i
)
9569 register_fair_sched_group(tg
, i
);
9570 list_add_rcu(&tg
->siblings
, &tg
->parent
->children
);
9571 spin_unlock_irqrestore(&task_group_lock
, flags
);
9573 mutex_unlock(&shares_mutex
);
9577 unsigned long sched_group_shares(struct task_group
*tg
)
9583 #ifdef CONFIG_RT_GROUP_SCHED
9585 * Ensure that the real time constraints are schedulable.
9587 static DEFINE_MUTEX(rt_constraints_mutex
);
9589 static unsigned long to_ratio(u64 period
, u64 runtime
)
9591 if (runtime
== RUNTIME_INF
)
9594 return div64_u64(runtime
<< 20, period
);
9597 /* Must be called with tasklist_lock held */
9598 static inline int tg_has_rt_tasks(struct task_group
*tg
)
9600 struct task_struct
*g
, *p
;
9602 do_each_thread(g
, p
) {
9603 if (rt_task(p
) && rt_rq_of_se(&p
->rt
)->tg
== tg
)
9605 } while_each_thread(g
, p
);
9610 struct rt_schedulable_data
{
9611 struct task_group
*tg
;
9616 static int tg_schedulable(struct task_group
*tg
, void *data
)
9618 struct rt_schedulable_data
*d
= data
;
9619 struct task_group
*child
;
9620 unsigned long total
, sum
= 0;
9621 u64 period
, runtime
;
9623 period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
9624 runtime
= tg
->rt_bandwidth
.rt_runtime
;
9627 period
= d
->rt_period
;
9628 runtime
= d
->rt_runtime
;
9631 #ifdef CONFIG_USER_SCHED
9632 if (tg
== &root_task_group
) {
9633 period
= global_rt_period();
9634 runtime
= global_rt_runtime();
9639 * Cannot have more runtime than the period.
9641 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
9645 * Ensure we don't starve existing RT tasks.
9647 if (rt_bandwidth_enabled() && !runtime
&& tg_has_rt_tasks(tg
))
9650 total
= to_ratio(period
, runtime
);
9653 * Nobody can have more than the global setting allows.
9655 if (total
> to_ratio(global_rt_period(), global_rt_runtime()))
9659 * The sum of our children's runtime should not exceed our own.
9661 list_for_each_entry_rcu(child
, &tg
->children
, siblings
) {
9662 period
= ktime_to_ns(child
->rt_bandwidth
.rt_period
);
9663 runtime
= child
->rt_bandwidth
.rt_runtime
;
9665 if (child
== d
->tg
) {
9666 period
= d
->rt_period
;
9667 runtime
= d
->rt_runtime
;
9670 sum
+= to_ratio(period
, runtime
);
9679 static int __rt_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
)
9681 struct rt_schedulable_data data
= {
9683 .rt_period
= period
,
9684 .rt_runtime
= runtime
,
9687 return walk_tg_tree(tg_schedulable
, tg_nop
, &data
);
9690 static int tg_set_bandwidth(struct task_group
*tg
,
9691 u64 rt_period
, u64 rt_runtime
)
9695 mutex_lock(&rt_constraints_mutex
);
9696 read_lock(&tasklist_lock
);
9697 err
= __rt_schedulable(tg
, rt_period
, rt_runtime
);
9701 spin_lock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
9702 tg
->rt_bandwidth
.rt_period
= ns_to_ktime(rt_period
);
9703 tg
->rt_bandwidth
.rt_runtime
= rt_runtime
;
9705 for_each_possible_cpu(i
) {
9706 struct rt_rq
*rt_rq
= tg
->rt_rq
[i
];
9708 spin_lock(&rt_rq
->rt_runtime_lock
);
9709 rt_rq
->rt_runtime
= rt_runtime
;
9710 spin_unlock(&rt_rq
->rt_runtime_lock
);
9712 spin_unlock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
9714 read_unlock(&tasklist_lock
);
9715 mutex_unlock(&rt_constraints_mutex
);
9720 int sched_group_set_rt_runtime(struct task_group
*tg
, long rt_runtime_us
)
9722 u64 rt_runtime
, rt_period
;
9724 rt_period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
9725 rt_runtime
= (u64
)rt_runtime_us
* NSEC_PER_USEC
;
9726 if (rt_runtime_us
< 0)
9727 rt_runtime
= RUNTIME_INF
;
9729 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
9732 long sched_group_rt_runtime(struct task_group
*tg
)
9736 if (tg
->rt_bandwidth
.rt_runtime
== RUNTIME_INF
)
9739 rt_runtime_us
= tg
->rt_bandwidth
.rt_runtime
;
9740 do_div(rt_runtime_us
, NSEC_PER_USEC
);
9741 return rt_runtime_us
;
9744 int sched_group_set_rt_period(struct task_group
*tg
, long rt_period_us
)
9746 u64 rt_runtime
, rt_period
;
9748 rt_period
= (u64
)rt_period_us
* NSEC_PER_USEC
;
9749 rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
9754 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
9757 long sched_group_rt_period(struct task_group
*tg
)
9761 rt_period_us
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
9762 do_div(rt_period_us
, NSEC_PER_USEC
);
9763 return rt_period_us
;
9766 static int sched_rt_global_constraints(void)
9768 u64 runtime
, period
;
9771 if (sysctl_sched_rt_period
<= 0)
9774 runtime
= global_rt_runtime();
9775 period
= global_rt_period();
9778 * Sanity check on the sysctl variables.
9780 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
9783 mutex_lock(&rt_constraints_mutex
);
9784 read_lock(&tasklist_lock
);
9785 ret
= __rt_schedulable(NULL
, 0, 0);
9786 read_unlock(&tasklist_lock
);
9787 mutex_unlock(&rt_constraints_mutex
);
9792 int sched_rt_can_attach(struct task_group
*tg
, struct task_struct
*tsk
)
9794 /* Don't accept realtime tasks when there is no way for them to run */
9795 if (rt_task(tsk
) && tg
->rt_bandwidth
.rt_runtime
== 0)
9801 #else /* !CONFIG_RT_GROUP_SCHED */
9802 static int sched_rt_global_constraints(void)
9804 unsigned long flags
;
9807 if (sysctl_sched_rt_period
<= 0)
9810 spin_lock_irqsave(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
9811 for_each_possible_cpu(i
) {
9812 struct rt_rq
*rt_rq
= &cpu_rq(i
)->rt
;
9814 spin_lock(&rt_rq
->rt_runtime_lock
);
9815 rt_rq
->rt_runtime
= global_rt_runtime();
9816 spin_unlock(&rt_rq
->rt_runtime_lock
);
9818 spin_unlock_irqrestore(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
9822 #endif /* CONFIG_RT_GROUP_SCHED */
9824 int sched_rt_handler(struct ctl_table
*table
, int write
,
9825 struct file
*filp
, void __user
*buffer
, size_t *lenp
,
9829 int old_period
, old_runtime
;
9830 static DEFINE_MUTEX(mutex
);
9833 old_period
= sysctl_sched_rt_period
;
9834 old_runtime
= sysctl_sched_rt_runtime
;
9836 ret
= proc_dointvec(table
, write
, filp
, buffer
, lenp
, ppos
);
9838 if (!ret
&& write
) {
9839 ret
= sched_rt_global_constraints();
9841 sysctl_sched_rt_period
= old_period
;
9842 sysctl_sched_rt_runtime
= old_runtime
;
9844 def_rt_bandwidth
.rt_runtime
= global_rt_runtime();
9845 def_rt_bandwidth
.rt_period
=
9846 ns_to_ktime(global_rt_period());
9849 mutex_unlock(&mutex
);
9854 #ifdef CONFIG_CGROUP_SCHED
9856 /* return corresponding task_group object of a cgroup */
9857 static inline struct task_group
*cgroup_tg(struct cgroup
*cgrp
)
9859 return container_of(cgroup_subsys_state(cgrp
, cpu_cgroup_subsys_id
),
9860 struct task_group
, css
);
9863 static struct cgroup_subsys_state
*
9864 cpu_cgroup_create(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
9866 struct task_group
*tg
, *parent
;
9868 if (!cgrp
->parent
) {
9869 /* This is early initialization for the top cgroup */
9870 return &init_task_group
.css
;
9873 parent
= cgroup_tg(cgrp
->parent
);
9874 tg
= sched_create_group(parent
);
9876 return ERR_PTR(-ENOMEM
);
9882 cpu_cgroup_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
9884 struct task_group
*tg
= cgroup_tg(cgrp
);
9886 sched_destroy_group(tg
);
9890 cpu_cgroup_can_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
9891 struct task_struct
*tsk
)
9893 #ifdef CONFIG_RT_GROUP_SCHED
9894 if (!sched_rt_can_attach(cgroup_tg(cgrp
), tsk
))
9897 /* We don't support RT-tasks being in separate groups */
9898 if (tsk
->sched_class
!= &fair_sched_class
)
9906 cpu_cgroup_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
9907 struct cgroup
*old_cont
, struct task_struct
*tsk
)
9909 sched_move_task(tsk
);
9912 #ifdef CONFIG_FAIR_GROUP_SCHED
9913 static int cpu_shares_write_u64(struct cgroup
*cgrp
, struct cftype
*cftype
,
9916 return sched_group_set_shares(cgroup_tg(cgrp
), shareval
);
9919 static u64
cpu_shares_read_u64(struct cgroup
*cgrp
, struct cftype
*cft
)
9921 struct task_group
*tg
= cgroup_tg(cgrp
);
9923 return (u64
) tg
->shares
;
9925 #endif /* CONFIG_FAIR_GROUP_SCHED */
9927 #ifdef CONFIG_RT_GROUP_SCHED
9928 static int cpu_rt_runtime_write(struct cgroup
*cgrp
, struct cftype
*cft
,
9931 return sched_group_set_rt_runtime(cgroup_tg(cgrp
), val
);
9934 static s64
cpu_rt_runtime_read(struct cgroup
*cgrp
, struct cftype
*cft
)
9936 return sched_group_rt_runtime(cgroup_tg(cgrp
));
9939 static int cpu_rt_period_write_uint(struct cgroup
*cgrp
, struct cftype
*cftype
,
9942 return sched_group_set_rt_period(cgroup_tg(cgrp
), rt_period_us
);
9945 static u64
cpu_rt_period_read_uint(struct cgroup
*cgrp
, struct cftype
*cft
)
9947 return sched_group_rt_period(cgroup_tg(cgrp
));
9949 #endif /* CONFIG_RT_GROUP_SCHED */
9951 static struct cftype cpu_files
[] = {
9952 #ifdef CONFIG_FAIR_GROUP_SCHED
9955 .read_u64
= cpu_shares_read_u64
,
9956 .write_u64
= cpu_shares_write_u64
,
9959 #ifdef CONFIG_RT_GROUP_SCHED
9961 .name
= "rt_runtime_us",
9962 .read_s64
= cpu_rt_runtime_read
,
9963 .write_s64
= cpu_rt_runtime_write
,
9966 .name
= "rt_period_us",
9967 .read_u64
= cpu_rt_period_read_uint
,
9968 .write_u64
= cpu_rt_period_write_uint
,
9973 static int cpu_cgroup_populate(struct cgroup_subsys
*ss
, struct cgroup
*cont
)
9975 return cgroup_add_files(cont
, ss
, cpu_files
, ARRAY_SIZE(cpu_files
));
9978 struct cgroup_subsys cpu_cgroup_subsys
= {
9980 .create
= cpu_cgroup_create
,
9981 .destroy
= cpu_cgroup_destroy
,
9982 .can_attach
= cpu_cgroup_can_attach
,
9983 .attach
= cpu_cgroup_attach
,
9984 .populate
= cpu_cgroup_populate
,
9985 .subsys_id
= cpu_cgroup_subsys_id
,
9989 #endif /* CONFIG_CGROUP_SCHED */
9991 #ifdef CONFIG_CGROUP_CPUACCT
9994 * CPU accounting code for task groups.
9996 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
9997 * (balbir@in.ibm.com).
10000 /* track cpu usage of a group of tasks and its child groups */
10002 struct cgroup_subsys_state css
;
10003 /* cpuusage holds pointer to a u64-type object on every cpu */
10005 struct percpu_counter cpustat
[CPUACCT_STAT_NSTATS
];
10006 struct cpuacct
*parent
;
10009 struct cgroup_subsys cpuacct_subsys
;
10011 /* return cpu accounting group corresponding to this container */
10012 static inline struct cpuacct
*cgroup_ca(struct cgroup
*cgrp
)
10014 return container_of(cgroup_subsys_state(cgrp
, cpuacct_subsys_id
),
10015 struct cpuacct
, css
);
10018 /* return cpu accounting group to which this task belongs */
10019 static inline struct cpuacct
*task_ca(struct task_struct
*tsk
)
10021 return container_of(task_subsys_state(tsk
, cpuacct_subsys_id
),
10022 struct cpuacct
, css
);
10025 /* create a new cpu accounting group */
10026 static struct cgroup_subsys_state
*cpuacct_create(
10027 struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
10029 struct cpuacct
*ca
= kzalloc(sizeof(*ca
), GFP_KERNEL
);
10035 ca
->cpuusage
= alloc_percpu(u64
);
10039 for (i
= 0; i
< CPUACCT_STAT_NSTATS
; i
++)
10040 if (percpu_counter_init(&ca
->cpustat
[i
], 0))
10041 goto out_free_counters
;
10044 ca
->parent
= cgroup_ca(cgrp
->parent
);
10050 percpu_counter_destroy(&ca
->cpustat
[i
]);
10051 free_percpu(ca
->cpuusage
);
10055 return ERR_PTR(-ENOMEM
);
10058 /* destroy an existing cpu accounting group */
10060 cpuacct_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
10062 struct cpuacct
*ca
= cgroup_ca(cgrp
);
10065 for (i
= 0; i
< CPUACCT_STAT_NSTATS
; i
++)
10066 percpu_counter_destroy(&ca
->cpustat
[i
]);
10067 free_percpu(ca
->cpuusage
);
10071 static u64
cpuacct_cpuusage_read(struct cpuacct
*ca
, int cpu
)
10073 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
10076 #ifndef CONFIG_64BIT
10078 * Take rq->lock to make 64-bit read safe on 32-bit platforms.
10080 spin_lock_irq(&cpu_rq(cpu
)->lock
);
10082 spin_unlock_irq(&cpu_rq(cpu
)->lock
);
10090 static void cpuacct_cpuusage_write(struct cpuacct
*ca
, int cpu
, u64 val
)
10092 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
10094 #ifndef CONFIG_64BIT
10096 * Take rq->lock to make 64-bit write safe on 32-bit platforms.
10098 spin_lock_irq(&cpu_rq(cpu
)->lock
);
10100 spin_unlock_irq(&cpu_rq(cpu
)->lock
);
10106 /* return total cpu usage (in nanoseconds) of a group */
10107 static u64
cpuusage_read(struct cgroup
*cgrp
, struct cftype
*cft
)
10109 struct cpuacct
*ca
= cgroup_ca(cgrp
);
10110 u64 totalcpuusage
= 0;
10113 for_each_present_cpu(i
)
10114 totalcpuusage
+= cpuacct_cpuusage_read(ca
, i
);
10116 return totalcpuusage
;
10119 static int cpuusage_write(struct cgroup
*cgrp
, struct cftype
*cftype
,
10122 struct cpuacct
*ca
= cgroup_ca(cgrp
);
10131 for_each_present_cpu(i
)
10132 cpuacct_cpuusage_write(ca
, i
, 0);
10138 static int cpuacct_percpu_seq_read(struct cgroup
*cgroup
, struct cftype
*cft
,
10139 struct seq_file
*m
)
10141 struct cpuacct
*ca
= cgroup_ca(cgroup
);
10145 for_each_present_cpu(i
) {
10146 percpu
= cpuacct_cpuusage_read(ca
, i
);
10147 seq_printf(m
, "%llu ", (unsigned long long) percpu
);
10149 seq_printf(m
, "\n");
10153 static const char *cpuacct_stat_desc
[] = {
10154 [CPUACCT_STAT_USER
] = "user",
10155 [CPUACCT_STAT_SYSTEM
] = "system",
10158 static int cpuacct_stats_show(struct cgroup
*cgrp
, struct cftype
*cft
,
10159 struct cgroup_map_cb
*cb
)
10161 struct cpuacct
*ca
= cgroup_ca(cgrp
);
10164 for (i
= 0; i
< CPUACCT_STAT_NSTATS
; i
++) {
10165 s64 val
= percpu_counter_read(&ca
->cpustat
[i
]);
10166 val
= cputime64_to_clock_t(val
);
10167 cb
->fill(cb
, cpuacct_stat_desc
[i
], val
);
10172 static struct cftype files
[] = {
10175 .read_u64
= cpuusage_read
,
10176 .write_u64
= cpuusage_write
,
10179 .name
= "usage_percpu",
10180 .read_seq_string
= cpuacct_percpu_seq_read
,
10184 .read_map
= cpuacct_stats_show
,
10188 static int cpuacct_populate(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
10190 return cgroup_add_files(cgrp
, ss
, files
, ARRAY_SIZE(files
));
10194 * charge this task's execution time to its accounting group.
10196 * called with rq->lock held.
10198 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
)
10200 struct cpuacct
*ca
;
10203 if (unlikely(!cpuacct_subsys
.active
))
10206 cpu
= task_cpu(tsk
);
10212 for (; ca
; ca
= ca
->parent
) {
10213 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
10214 *cpuusage
+= cputime
;
10221 * Charge the system/user time to the task's accounting group.
10223 static void cpuacct_update_stats(struct task_struct
*tsk
,
10224 enum cpuacct_stat_index idx
, cputime_t val
)
10226 struct cpuacct
*ca
;
10228 if (unlikely(!cpuacct_subsys
.active
))
10235 percpu_counter_add(&ca
->cpustat
[idx
], val
);
10241 struct cgroup_subsys cpuacct_subsys
= {
10243 .create
= cpuacct_create
,
10244 .destroy
= cpuacct_destroy
,
10245 .populate
= cpuacct_populate
,
10246 .subsys_id
= cpuacct_subsys_id
,
10248 #endif /* CONFIG_CGROUP_CPUACCT */