2 * kernel/workqueue.c - generic async execution with shared worker pool
4 * Copyright (C) 2002 Ingo Molnar
6 * Derived from the taskqueue/keventd code by:
7 * David Woodhouse <dwmw2@infradead.org>
9 * Kai Petzke <wpp@marie.physik.tu-berlin.de>
10 * Theodore Ts'o <tytso@mit.edu>
12 * Made to use alloc_percpu by Christoph Lameter.
14 * Copyright (C) 2010 SUSE Linux Products GmbH
15 * Copyright (C) 2010 Tejun Heo <tj@kernel.org>
17 * This is the generic async execution mechanism. Work items as are
18 * executed in process context. The worker pool is shared and
19 * automatically managed. There is one worker pool for each CPU and
20 * one extra for works which are better served by workers which are
21 * not bound to any specific CPU.
23 * Please read Documentation/workqueue.txt for details.
26 #include <linux/export.h>
27 #include <linux/kernel.h>
28 #include <linux/sched.h>
29 #include <linux/init.h>
30 #include <linux/signal.h>
31 #include <linux/completion.h>
32 #include <linux/workqueue.h>
33 #include <linux/slab.h>
34 #include <linux/cpu.h>
35 #include <linux/notifier.h>
36 #include <linux/kthread.h>
37 #include <linux/hardirq.h>
38 #include <linux/mempolicy.h>
39 #include <linux/freezer.h>
40 #include <linux/kallsyms.h>
41 #include <linux/debug_locks.h>
42 #include <linux/lockdep.h>
43 #include <linux/idr.h>
45 #include "workqueue_sched.h"
51 * A bound gcwq is either associated or disassociated with its CPU.
52 * While associated (!DISASSOCIATED), all workers are bound to the
53 * CPU and none has %WORKER_UNBOUND set and concurrency management
56 * While DISASSOCIATED, the cpu may be offline and all workers have
57 * %WORKER_UNBOUND set and concurrency management disabled, and may
58 * be executing on any CPU. The gcwq behaves as an unbound one.
60 * Note that DISASSOCIATED can be flipped only while holding
61 * managership of all pools on the gcwq to avoid changing binding
62 * state while create_worker() is in progress.
64 GCWQ_DISASSOCIATED
= 1 << 0, /* cpu can't serve workers */
65 GCWQ_FREEZING
= 1 << 1, /* freeze in progress */
68 POOL_MANAGE_WORKERS
= 1 << 0, /* need to manage workers */
69 POOL_MANAGING_WORKERS
= 1 << 1, /* managing workers */
72 WORKER_STARTED
= 1 << 0, /* started */
73 WORKER_DIE
= 1 << 1, /* die die die */
74 WORKER_IDLE
= 1 << 2, /* is idle */
75 WORKER_PREP
= 1 << 3, /* preparing to run works */
76 WORKER_REBIND
= 1 << 5, /* mom is home, come back */
77 WORKER_CPU_INTENSIVE
= 1 << 6, /* cpu intensive */
78 WORKER_UNBOUND
= 1 << 7, /* worker is unbound */
80 WORKER_NOT_RUNNING
= WORKER_PREP
| WORKER_REBIND
| WORKER_UNBOUND
|
83 NR_WORKER_POOLS
= 2, /* # worker pools per gcwq */
85 BUSY_WORKER_HASH_ORDER
= 6, /* 64 pointers */
86 BUSY_WORKER_HASH_SIZE
= 1 << BUSY_WORKER_HASH_ORDER
,
87 BUSY_WORKER_HASH_MASK
= BUSY_WORKER_HASH_SIZE
- 1,
89 MAX_IDLE_WORKERS_RATIO
= 4, /* 1/4 of busy can be idle */
90 IDLE_WORKER_TIMEOUT
= 300 * HZ
, /* keep idle ones for 5 mins */
92 MAYDAY_INITIAL_TIMEOUT
= HZ
/ 100 >= 2 ? HZ
/ 100 : 2,
93 /* call for help after 10ms
95 MAYDAY_INTERVAL
= HZ
/ 10, /* and then every 100ms */
96 CREATE_COOLDOWN
= HZ
, /* time to breath after fail */
99 * Rescue workers are used only on emergencies and shared by
100 * all cpus. Give -20.
102 RESCUER_NICE_LEVEL
= -20,
103 HIGHPRI_NICE_LEVEL
= -20,
107 * Structure fields follow one of the following exclusion rules.
109 * I: Modifiable by initialization/destruction paths and read-only for
112 * P: Preemption protected. Disabling preemption is enough and should
113 * only be modified and accessed from the local cpu.
115 * L: gcwq->lock protected. Access with gcwq->lock held.
117 * X: During normal operation, modification requires gcwq->lock and
118 * should be done only from local cpu. Either disabling preemption
119 * on local cpu or grabbing gcwq->lock is enough for read access.
120 * If GCWQ_DISASSOCIATED is set, it's identical to L.
122 * F: wq->flush_mutex protected.
124 * W: workqueue_lock protected.
132 * The poor guys doing the actual heavy lifting. All on-duty workers
133 * are either serving the manager role, on idle list or on busy hash.
136 /* on idle list while idle, on busy hash table while busy */
138 struct list_head entry
; /* L: while idle */
139 struct hlist_node hentry
; /* L: while busy */
142 struct work_struct
*current_work
; /* L: work being processed */
143 struct cpu_workqueue_struct
*current_cwq
; /* L: current_work's cwq */
144 struct list_head scheduled
; /* L: scheduled works */
145 struct task_struct
*task
; /* I: worker task */
146 struct worker_pool
*pool
; /* I: the associated pool */
147 /* 64 bytes boundary on 64bit, 32 on 32bit */
148 unsigned long last_active
; /* L: last active timestamp */
149 unsigned int flags
; /* X: flags */
150 int id
; /* I: worker id */
152 /* for rebinding worker to CPU */
153 struct idle_rebind
*idle_rebind
; /* L: for idle worker */
154 struct work_struct rebind_work
; /* L: for busy worker */
158 struct global_cwq
*gcwq
; /* I: the owning gcwq */
159 unsigned int flags
; /* X: flags */
161 struct list_head worklist
; /* L: list of pending works */
162 int nr_workers
; /* L: total number of workers */
163 int nr_idle
; /* L: currently idle ones */
165 struct list_head idle_list
; /* X: list of idle workers */
166 struct timer_list idle_timer
; /* L: worker idle timeout */
167 struct timer_list mayday_timer
; /* L: SOS timer for workers */
169 struct mutex manager_mutex
; /* mutex manager should hold */
170 struct ida worker_ida
; /* L: for worker IDs */
174 * Global per-cpu workqueue. There's one and only one for each cpu
175 * and all works are queued and processed here regardless of their
179 spinlock_t lock
; /* the gcwq lock */
180 unsigned int cpu
; /* I: the associated cpu */
181 unsigned int flags
; /* L: GCWQ_* flags */
183 /* workers are chained either in busy_hash or pool idle_list */
184 struct hlist_head busy_hash
[BUSY_WORKER_HASH_SIZE
];
185 /* L: hash of busy workers */
187 struct worker_pool pools
[2]; /* normal and highpri pools */
189 wait_queue_head_t rebind_hold
; /* rebind hold wait */
190 } ____cacheline_aligned_in_smp
;
193 * The per-CPU workqueue. The lower WORK_STRUCT_FLAG_BITS of
194 * work_struct->data are used for flags and thus cwqs need to be
195 * aligned at two's power of the number of flag bits.
197 struct cpu_workqueue_struct
{
198 struct worker_pool
*pool
; /* I: the associated pool */
199 struct workqueue_struct
*wq
; /* I: the owning workqueue */
200 int work_color
; /* L: current color */
201 int flush_color
; /* L: flushing color */
202 int nr_in_flight
[WORK_NR_COLORS
];
203 /* L: nr of in_flight works */
204 int nr_active
; /* L: nr of active works */
205 int max_active
; /* L: max active works */
206 struct list_head delayed_works
; /* L: delayed works */
210 * Structure used to wait for workqueue flush.
213 struct list_head list
; /* F: list of flushers */
214 int flush_color
; /* F: flush color waiting for */
215 struct completion done
; /* flush completion */
219 * All cpumasks are assumed to be always set on UP and thus can't be
220 * used to determine whether there's something to be done.
223 typedef cpumask_var_t mayday_mask_t
;
224 #define mayday_test_and_set_cpu(cpu, mask) \
225 cpumask_test_and_set_cpu((cpu), (mask))
226 #define mayday_clear_cpu(cpu, mask) cpumask_clear_cpu((cpu), (mask))
227 #define for_each_mayday_cpu(cpu, mask) for_each_cpu((cpu), (mask))
228 #define alloc_mayday_mask(maskp, gfp) zalloc_cpumask_var((maskp), (gfp))
229 #define free_mayday_mask(mask) free_cpumask_var((mask))
231 typedef unsigned long mayday_mask_t
;
232 #define mayday_test_and_set_cpu(cpu, mask) test_and_set_bit(0, &(mask))
233 #define mayday_clear_cpu(cpu, mask) clear_bit(0, &(mask))
234 #define for_each_mayday_cpu(cpu, mask) if ((cpu) = 0, (mask))
235 #define alloc_mayday_mask(maskp, gfp) true
236 #define free_mayday_mask(mask) do { } while (0)
240 * The externally visible workqueue abstraction is an array of
241 * per-CPU workqueues:
243 struct workqueue_struct
{
244 unsigned int flags
; /* W: WQ_* flags */
246 struct cpu_workqueue_struct __percpu
*pcpu
;
247 struct cpu_workqueue_struct
*single
;
249 } cpu_wq
; /* I: cwq's */
250 struct list_head list
; /* W: list of all workqueues */
252 struct mutex flush_mutex
; /* protects wq flushing */
253 int work_color
; /* F: current work color */
254 int flush_color
; /* F: current flush color */
255 atomic_t nr_cwqs_to_flush
; /* flush in progress */
256 struct wq_flusher
*first_flusher
; /* F: first flusher */
257 struct list_head flusher_queue
; /* F: flush waiters */
258 struct list_head flusher_overflow
; /* F: flush overflow list */
260 mayday_mask_t mayday_mask
; /* cpus requesting rescue */
261 struct worker
*rescuer
; /* I: rescue worker */
263 int nr_drainers
; /* W: drain in progress */
264 int saved_max_active
; /* W: saved cwq max_active */
265 #ifdef CONFIG_LOCKDEP
266 struct lockdep_map lockdep_map
;
268 char name
[]; /* I: workqueue name */
271 struct workqueue_struct
*system_wq __read_mostly
;
272 struct workqueue_struct
*system_long_wq __read_mostly
;
273 struct workqueue_struct
*system_nrt_wq __read_mostly
;
274 struct workqueue_struct
*system_unbound_wq __read_mostly
;
275 struct workqueue_struct
*system_freezable_wq __read_mostly
;
276 struct workqueue_struct
*system_nrt_freezable_wq __read_mostly
;
277 EXPORT_SYMBOL_GPL(system_wq
);
278 EXPORT_SYMBOL_GPL(system_long_wq
);
279 EXPORT_SYMBOL_GPL(system_nrt_wq
);
280 EXPORT_SYMBOL_GPL(system_unbound_wq
);
281 EXPORT_SYMBOL_GPL(system_freezable_wq
);
282 EXPORT_SYMBOL_GPL(system_nrt_freezable_wq
);
284 #define CREATE_TRACE_POINTS
285 #include <trace/events/workqueue.h>
287 #define for_each_worker_pool(pool, gcwq) \
288 for ((pool) = &(gcwq)->pools[0]; \
289 (pool) < &(gcwq)->pools[NR_WORKER_POOLS]; (pool)++)
291 #define for_each_busy_worker(worker, i, pos, gcwq) \
292 for (i = 0; i < BUSY_WORKER_HASH_SIZE; i++) \
293 hlist_for_each_entry(worker, pos, &gcwq->busy_hash[i], hentry)
295 static inline int __next_gcwq_cpu(int cpu
, const struct cpumask
*mask
,
298 if (cpu
< nr_cpu_ids
) {
300 cpu
= cpumask_next(cpu
, mask
);
301 if (cpu
< nr_cpu_ids
)
305 return WORK_CPU_UNBOUND
;
307 return WORK_CPU_NONE
;
310 static inline int __next_wq_cpu(int cpu
, const struct cpumask
*mask
,
311 struct workqueue_struct
*wq
)
313 return __next_gcwq_cpu(cpu
, mask
, !(wq
->flags
& WQ_UNBOUND
) ? 1 : 2);
319 * An extra gcwq is defined for an invalid cpu number
320 * (WORK_CPU_UNBOUND) to host workqueues which are not bound to any
321 * specific CPU. The following iterators are similar to
322 * for_each_*_cpu() iterators but also considers the unbound gcwq.
324 * for_each_gcwq_cpu() : possible CPUs + WORK_CPU_UNBOUND
325 * for_each_online_gcwq_cpu() : online CPUs + WORK_CPU_UNBOUND
326 * for_each_cwq_cpu() : possible CPUs for bound workqueues,
327 * WORK_CPU_UNBOUND for unbound workqueues
329 #define for_each_gcwq_cpu(cpu) \
330 for ((cpu) = __next_gcwq_cpu(-1, cpu_possible_mask, 3); \
331 (cpu) < WORK_CPU_NONE; \
332 (cpu) = __next_gcwq_cpu((cpu), cpu_possible_mask, 3))
334 #define for_each_online_gcwq_cpu(cpu) \
335 for ((cpu) = __next_gcwq_cpu(-1, cpu_online_mask, 3); \
336 (cpu) < WORK_CPU_NONE; \
337 (cpu) = __next_gcwq_cpu((cpu), cpu_online_mask, 3))
339 #define for_each_cwq_cpu(cpu, wq) \
340 for ((cpu) = __next_wq_cpu(-1, cpu_possible_mask, (wq)); \
341 (cpu) < WORK_CPU_NONE; \
342 (cpu) = __next_wq_cpu((cpu), cpu_possible_mask, (wq)))
344 #ifdef CONFIG_DEBUG_OBJECTS_WORK
346 static struct debug_obj_descr work_debug_descr
;
348 static void *work_debug_hint(void *addr
)
350 return ((struct work_struct
*) addr
)->func
;
354 * fixup_init is called when:
355 * - an active object is initialized
357 static int work_fixup_init(void *addr
, enum debug_obj_state state
)
359 struct work_struct
*work
= addr
;
362 case ODEBUG_STATE_ACTIVE
:
363 cancel_work_sync(work
);
364 debug_object_init(work
, &work_debug_descr
);
372 * fixup_activate is called when:
373 * - an active object is activated
374 * - an unknown object is activated (might be a statically initialized object)
376 static int work_fixup_activate(void *addr
, enum debug_obj_state state
)
378 struct work_struct
*work
= addr
;
382 case ODEBUG_STATE_NOTAVAILABLE
:
384 * This is not really a fixup. The work struct was
385 * statically initialized. We just make sure that it
386 * is tracked in the object tracker.
388 if (test_bit(WORK_STRUCT_STATIC_BIT
, work_data_bits(work
))) {
389 debug_object_init(work
, &work_debug_descr
);
390 debug_object_activate(work
, &work_debug_descr
);
396 case ODEBUG_STATE_ACTIVE
:
405 * fixup_free is called when:
406 * - an active object is freed
408 static int work_fixup_free(void *addr
, enum debug_obj_state state
)
410 struct work_struct
*work
= addr
;
413 case ODEBUG_STATE_ACTIVE
:
414 cancel_work_sync(work
);
415 debug_object_free(work
, &work_debug_descr
);
422 static struct debug_obj_descr work_debug_descr
= {
423 .name
= "work_struct",
424 .debug_hint
= work_debug_hint
,
425 .fixup_init
= work_fixup_init
,
426 .fixup_activate
= work_fixup_activate
,
427 .fixup_free
= work_fixup_free
,
430 static inline void debug_work_activate(struct work_struct
*work
)
432 debug_object_activate(work
, &work_debug_descr
);
435 static inline void debug_work_deactivate(struct work_struct
*work
)
437 debug_object_deactivate(work
, &work_debug_descr
);
440 void __init_work(struct work_struct
*work
, int onstack
)
443 debug_object_init_on_stack(work
, &work_debug_descr
);
445 debug_object_init(work
, &work_debug_descr
);
447 EXPORT_SYMBOL_GPL(__init_work
);
449 void destroy_work_on_stack(struct work_struct
*work
)
451 debug_object_free(work
, &work_debug_descr
);
453 EXPORT_SYMBOL_GPL(destroy_work_on_stack
);
456 static inline void debug_work_activate(struct work_struct
*work
) { }
457 static inline void debug_work_deactivate(struct work_struct
*work
) { }
460 /* Serializes the accesses to the list of workqueues. */
461 static DEFINE_SPINLOCK(workqueue_lock
);
462 static LIST_HEAD(workqueues
);
463 static bool workqueue_freezing
; /* W: have wqs started freezing? */
466 * The almighty global cpu workqueues. nr_running is the only field
467 * which is expected to be used frequently by other cpus via
468 * try_to_wake_up(). Put it in a separate cacheline.
470 static DEFINE_PER_CPU(struct global_cwq
, global_cwq
);
471 static DEFINE_PER_CPU_SHARED_ALIGNED(atomic_t
, pool_nr_running
[NR_WORKER_POOLS
]);
474 * Global cpu workqueue and nr_running counter for unbound gcwq. The
475 * gcwq is always online, has GCWQ_DISASSOCIATED set, and all its
476 * workers have WORKER_UNBOUND set.
478 static struct global_cwq unbound_global_cwq
;
479 static atomic_t unbound_pool_nr_running
[NR_WORKER_POOLS
] = {
480 [0 ... NR_WORKER_POOLS
- 1] = ATOMIC_INIT(0), /* always 0 */
483 static int worker_thread(void *__worker
);
485 static int worker_pool_pri(struct worker_pool
*pool
)
487 return pool
- pool
->gcwq
->pools
;
490 static struct global_cwq
*get_gcwq(unsigned int cpu
)
492 if (cpu
!= WORK_CPU_UNBOUND
)
493 return &per_cpu(global_cwq
, cpu
);
495 return &unbound_global_cwq
;
498 static atomic_t
*get_pool_nr_running(struct worker_pool
*pool
)
500 int cpu
= pool
->gcwq
->cpu
;
501 int idx
= worker_pool_pri(pool
);
503 if (cpu
!= WORK_CPU_UNBOUND
)
504 return &per_cpu(pool_nr_running
, cpu
)[idx
];
506 return &unbound_pool_nr_running
[idx
];
509 static struct cpu_workqueue_struct
*get_cwq(unsigned int cpu
,
510 struct workqueue_struct
*wq
)
512 if (!(wq
->flags
& WQ_UNBOUND
)) {
513 if (likely(cpu
< nr_cpu_ids
))
514 return per_cpu_ptr(wq
->cpu_wq
.pcpu
, cpu
);
515 } else if (likely(cpu
== WORK_CPU_UNBOUND
))
516 return wq
->cpu_wq
.single
;
520 static unsigned int work_color_to_flags(int color
)
522 return color
<< WORK_STRUCT_COLOR_SHIFT
;
525 static int get_work_color(struct work_struct
*work
)
527 return (*work_data_bits(work
) >> WORK_STRUCT_COLOR_SHIFT
) &
528 ((1 << WORK_STRUCT_COLOR_BITS
) - 1);
531 static int work_next_color(int color
)
533 return (color
+ 1) % WORK_NR_COLORS
;
537 * A work's data points to the cwq with WORK_STRUCT_CWQ set while the
538 * work is on queue. Once execution starts, WORK_STRUCT_CWQ is
539 * cleared and the work data contains the cpu number it was last on.
541 * set_work_{cwq|cpu}() and clear_work_data() can be used to set the
542 * cwq, cpu or clear work->data. These functions should only be
543 * called while the work is owned - ie. while the PENDING bit is set.
545 * get_work_[g]cwq() can be used to obtain the gcwq or cwq
546 * corresponding to a work. gcwq is available once the work has been
547 * queued anywhere after initialization. cwq is available only from
548 * queueing until execution starts.
550 static inline void set_work_data(struct work_struct
*work
, unsigned long data
,
553 BUG_ON(!work_pending(work
));
554 atomic_long_set(&work
->data
, data
| flags
| work_static(work
));
557 static void set_work_cwq(struct work_struct
*work
,
558 struct cpu_workqueue_struct
*cwq
,
559 unsigned long extra_flags
)
561 set_work_data(work
, (unsigned long)cwq
,
562 WORK_STRUCT_PENDING
| WORK_STRUCT_CWQ
| extra_flags
);
565 static void set_work_cpu(struct work_struct
*work
, unsigned int cpu
)
567 set_work_data(work
, cpu
<< WORK_STRUCT_FLAG_BITS
, WORK_STRUCT_PENDING
);
570 static void clear_work_data(struct work_struct
*work
)
572 set_work_data(work
, WORK_STRUCT_NO_CPU
, 0);
575 static struct cpu_workqueue_struct
*get_work_cwq(struct work_struct
*work
)
577 unsigned long data
= atomic_long_read(&work
->data
);
579 if (data
& WORK_STRUCT_CWQ
)
580 return (void *)(data
& WORK_STRUCT_WQ_DATA_MASK
);
585 static struct global_cwq
*get_work_gcwq(struct work_struct
*work
)
587 unsigned long data
= atomic_long_read(&work
->data
);
590 if (data
& WORK_STRUCT_CWQ
)
591 return ((struct cpu_workqueue_struct
*)
592 (data
& WORK_STRUCT_WQ_DATA_MASK
))->pool
->gcwq
;
594 cpu
= data
>> WORK_STRUCT_FLAG_BITS
;
595 if (cpu
== WORK_CPU_NONE
)
598 BUG_ON(cpu
>= nr_cpu_ids
&& cpu
!= WORK_CPU_UNBOUND
);
599 return get_gcwq(cpu
);
603 * Policy functions. These define the policies on how the global worker
604 * pools are managed. Unless noted otherwise, these functions assume that
605 * they're being called with gcwq->lock held.
608 static bool __need_more_worker(struct worker_pool
*pool
)
610 return !atomic_read(get_pool_nr_running(pool
));
614 * Need to wake up a worker? Called from anything but currently
617 * Note that, because unbound workers never contribute to nr_running, this
618 * function will always return %true for unbound gcwq as long as the
619 * worklist isn't empty.
621 static bool need_more_worker(struct worker_pool
*pool
)
623 return !list_empty(&pool
->worklist
) && __need_more_worker(pool
);
626 /* Can I start working? Called from busy but !running workers. */
627 static bool may_start_working(struct worker_pool
*pool
)
629 return pool
->nr_idle
;
632 /* Do I need to keep working? Called from currently running workers. */
633 static bool keep_working(struct worker_pool
*pool
)
635 atomic_t
*nr_running
= get_pool_nr_running(pool
);
637 return !list_empty(&pool
->worklist
) && atomic_read(nr_running
) <= 1;
640 /* Do we need a new worker? Called from manager. */
641 static bool need_to_create_worker(struct worker_pool
*pool
)
643 return need_more_worker(pool
) && !may_start_working(pool
);
646 /* Do I need to be the manager? */
647 static bool need_to_manage_workers(struct worker_pool
*pool
)
649 return need_to_create_worker(pool
) ||
650 (pool
->flags
& POOL_MANAGE_WORKERS
);
653 /* Do we have too many workers and should some go away? */
654 static bool too_many_workers(struct worker_pool
*pool
)
656 bool managing
= pool
->flags
& POOL_MANAGING_WORKERS
;
657 int nr_idle
= pool
->nr_idle
+ managing
; /* manager is considered idle */
658 int nr_busy
= pool
->nr_workers
- nr_idle
;
660 return nr_idle
> 2 && (nr_idle
- 2) * MAX_IDLE_WORKERS_RATIO
>= nr_busy
;
667 /* Return the first worker. Safe with preemption disabled */
668 static struct worker
*first_worker(struct worker_pool
*pool
)
670 if (unlikely(list_empty(&pool
->idle_list
)))
673 return list_first_entry(&pool
->idle_list
, struct worker
, entry
);
677 * wake_up_worker - wake up an idle worker
678 * @pool: worker pool to wake worker from
680 * Wake up the first idle worker of @pool.
683 * spin_lock_irq(gcwq->lock).
685 static void wake_up_worker(struct worker_pool
*pool
)
687 struct worker
*worker
= first_worker(pool
);
690 wake_up_process(worker
->task
);
694 * wq_worker_waking_up - a worker is waking up
695 * @task: task waking up
696 * @cpu: CPU @task is waking up to
698 * This function is called during try_to_wake_up() when a worker is
702 * spin_lock_irq(rq->lock)
704 void wq_worker_waking_up(struct task_struct
*task
, unsigned int cpu
)
706 struct worker
*worker
= kthread_data(task
);
708 if (!(worker
->flags
& WORKER_NOT_RUNNING
))
709 atomic_inc(get_pool_nr_running(worker
->pool
));
713 * wq_worker_sleeping - a worker is going to sleep
714 * @task: task going to sleep
715 * @cpu: CPU in question, must be the current CPU number
717 * This function is called during schedule() when a busy worker is
718 * going to sleep. Worker on the same cpu can be woken up by
719 * returning pointer to its task.
722 * spin_lock_irq(rq->lock)
725 * Worker task on @cpu to wake up, %NULL if none.
727 struct task_struct
*wq_worker_sleeping(struct task_struct
*task
,
730 struct worker
*worker
= kthread_data(task
), *to_wakeup
= NULL
;
731 struct worker_pool
*pool
= worker
->pool
;
732 atomic_t
*nr_running
= get_pool_nr_running(pool
);
734 if (worker
->flags
& WORKER_NOT_RUNNING
)
737 /* this can only happen on the local cpu */
738 BUG_ON(cpu
!= raw_smp_processor_id());
741 * The counterpart of the following dec_and_test, implied mb,
742 * worklist not empty test sequence is in insert_work().
743 * Please read comment there.
745 * NOT_RUNNING is clear. This means that we're bound to and
746 * running on the local cpu w/ rq lock held and preemption
747 * disabled, which in turn means that none else could be
748 * manipulating idle_list, so dereferencing idle_list without gcwq
751 if (atomic_dec_and_test(nr_running
) && !list_empty(&pool
->worklist
))
752 to_wakeup
= first_worker(pool
);
753 return to_wakeup
? to_wakeup
->task
: NULL
;
757 * worker_set_flags - set worker flags and adjust nr_running accordingly
759 * @flags: flags to set
760 * @wakeup: wakeup an idle worker if necessary
762 * Set @flags in @worker->flags and adjust nr_running accordingly. If
763 * nr_running becomes zero and @wakeup is %true, an idle worker is
767 * spin_lock_irq(gcwq->lock)
769 static inline void worker_set_flags(struct worker
*worker
, unsigned int flags
,
772 struct worker_pool
*pool
= worker
->pool
;
774 WARN_ON_ONCE(worker
->task
!= current
);
777 * If transitioning into NOT_RUNNING, adjust nr_running and
778 * wake up an idle worker as necessary if requested by
781 if ((flags
& WORKER_NOT_RUNNING
) &&
782 !(worker
->flags
& WORKER_NOT_RUNNING
)) {
783 atomic_t
*nr_running
= get_pool_nr_running(pool
);
786 if (atomic_dec_and_test(nr_running
) &&
787 !list_empty(&pool
->worklist
))
788 wake_up_worker(pool
);
790 atomic_dec(nr_running
);
793 worker
->flags
|= flags
;
797 * worker_clr_flags - clear worker flags and adjust nr_running accordingly
799 * @flags: flags to clear
801 * Clear @flags in @worker->flags and adjust nr_running accordingly.
804 * spin_lock_irq(gcwq->lock)
806 static inline void worker_clr_flags(struct worker
*worker
, unsigned int flags
)
808 struct worker_pool
*pool
= worker
->pool
;
809 unsigned int oflags
= worker
->flags
;
811 WARN_ON_ONCE(worker
->task
!= current
);
813 worker
->flags
&= ~flags
;
816 * If transitioning out of NOT_RUNNING, increment nr_running. Note
817 * that the nested NOT_RUNNING is not a noop. NOT_RUNNING is mask
818 * of multiple flags, not a single flag.
820 if ((flags
& WORKER_NOT_RUNNING
) && (oflags
& WORKER_NOT_RUNNING
))
821 if (!(worker
->flags
& WORKER_NOT_RUNNING
))
822 atomic_inc(get_pool_nr_running(pool
));
826 * busy_worker_head - return the busy hash head for a work
827 * @gcwq: gcwq of interest
828 * @work: work to be hashed
830 * Return hash head of @gcwq for @work.
833 * spin_lock_irq(gcwq->lock).
836 * Pointer to the hash head.
838 static struct hlist_head
*busy_worker_head(struct global_cwq
*gcwq
,
839 struct work_struct
*work
)
841 const int base_shift
= ilog2(sizeof(struct work_struct
));
842 unsigned long v
= (unsigned long)work
;
844 /* simple shift and fold hash, do we need something better? */
846 v
+= v
>> BUSY_WORKER_HASH_ORDER
;
847 v
&= BUSY_WORKER_HASH_MASK
;
849 return &gcwq
->busy_hash
[v
];
853 * __find_worker_executing_work - find worker which is executing a work
854 * @gcwq: gcwq of interest
855 * @bwh: hash head as returned by busy_worker_head()
856 * @work: work to find worker for
858 * Find a worker which is executing @work on @gcwq. @bwh should be
859 * the hash head obtained by calling busy_worker_head() with the same
863 * spin_lock_irq(gcwq->lock).
866 * Pointer to worker which is executing @work if found, NULL
869 static struct worker
*__find_worker_executing_work(struct global_cwq
*gcwq
,
870 struct hlist_head
*bwh
,
871 struct work_struct
*work
)
873 struct worker
*worker
;
874 struct hlist_node
*tmp
;
876 hlist_for_each_entry(worker
, tmp
, bwh
, hentry
)
877 if (worker
->current_work
== work
)
883 * find_worker_executing_work - find worker which is executing a work
884 * @gcwq: gcwq of interest
885 * @work: work to find worker for
887 * Find a worker which is executing @work on @gcwq. This function is
888 * identical to __find_worker_executing_work() except that this
889 * function calculates @bwh itself.
892 * spin_lock_irq(gcwq->lock).
895 * Pointer to worker which is executing @work if found, NULL
898 static struct worker
*find_worker_executing_work(struct global_cwq
*gcwq
,
899 struct work_struct
*work
)
901 return __find_worker_executing_work(gcwq
, busy_worker_head(gcwq
, work
),
906 * insert_work - insert a work into gcwq
907 * @cwq: cwq @work belongs to
908 * @work: work to insert
909 * @head: insertion point
910 * @extra_flags: extra WORK_STRUCT_* flags to set
912 * Insert @work which belongs to @cwq into @gcwq after @head.
913 * @extra_flags is or'd to work_struct flags.
916 * spin_lock_irq(gcwq->lock).
918 static void insert_work(struct cpu_workqueue_struct
*cwq
,
919 struct work_struct
*work
, struct list_head
*head
,
920 unsigned int extra_flags
)
922 struct worker_pool
*pool
= cwq
->pool
;
924 /* we own @work, set data and link */
925 set_work_cwq(work
, cwq
, extra_flags
);
928 * Ensure that we get the right work->data if we see the
929 * result of list_add() below, see try_to_grab_pending().
933 list_add_tail(&work
->entry
, head
);
936 * Ensure either worker_sched_deactivated() sees the above
937 * list_add_tail() or we see zero nr_running to avoid workers
938 * lying around lazily while there are works to be processed.
942 if (__need_more_worker(pool
))
943 wake_up_worker(pool
);
947 * Test whether @work is being queued from another work executing on the
948 * same workqueue. This is rather expensive and should only be used from
951 static bool is_chained_work(struct workqueue_struct
*wq
)
956 for_each_gcwq_cpu(cpu
) {
957 struct global_cwq
*gcwq
= get_gcwq(cpu
);
958 struct worker
*worker
;
959 struct hlist_node
*pos
;
962 spin_lock_irqsave(&gcwq
->lock
, flags
);
963 for_each_busy_worker(worker
, i
, pos
, gcwq
) {
964 if (worker
->task
!= current
)
966 spin_unlock_irqrestore(&gcwq
->lock
, flags
);
968 * I'm @worker, no locking necessary. See if @work
969 * is headed to the same workqueue.
971 return worker
->current_cwq
->wq
== wq
;
973 spin_unlock_irqrestore(&gcwq
->lock
, flags
);
978 static void __queue_work(unsigned int cpu
, struct workqueue_struct
*wq
,
979 struct work_struct
*work
)
981 struct global_cwq
*gcwq
;
982 struct cpu_workqueue_struct
*cwq
;
983 struct list_head
*worklist
;
984 unsigned int work_flags
;
987 debug_work_activate(work
);
989 /* if dying, only works from the same workqueue are allowed */
990 if (unlikely(wq
->flags
& WQ_DRAINING
) &&
991 WARN_ON_ONCE(!is_chained_work(wq
)))
994 /* determine gcwq to use */
995 if (!(wq
->flags
& WQ_UNBOUND
)) {
996 struct global_cwq
*last_gcwq
;
998 if (unlikely(cpu
== WORK_CPU_UNBOUND
))
999 cpu
= raw_smp_processor_id();
1002 * It's multi cpu. If @wq is non-reentrant and @work
1003 * was previously on a different cpu, it might still
1004 * be running there, in which case the work needs to
1005 * be queued on that cpu to guarantee non-reentrance.
1007 gcwq
= get_gcwq(cpu
);
1008 if (wq
->flags
& WQ_NON_REENTRANT
&&
1009 (last_gcwq
= get_work_gcwq(work
)) && last_gcwq
!= gcwq
) {
1010 struct worker
*worker
;
1012 spin_lock_irqsave(&last_gcwq
->lock
, flags
);
1014 worker
= find_worker_executing_work(last_gcwq
, work
);
1016 if (worker
&& worker
->current_cwq
->wq
== wq
)
1019 /* meh... not running there, queue here */
1020 spin_unlock_irqrestore(&last_gcwq
->lock
, flags
);
1021 spin_lock_irqsave(&gcwq
->lock
, flags
);
1024 spin_lock_irqsave(&gcwq
->lock
, flags
);
1026 gcwq
= get_gcwq(WORK_CPU_UNBOUND
);
1027 spin_lock_irqsave(&gcwq
->lock
, flags
);
1030 /* gcwq determined, get cwq and queue */
1031 cwq
= get_cwq(gcwq
->cpu
, wq
);
1032 trace_workqueue_queue_work(cpu
, cwq
, work
);
1034 if (WARN_ON(!list_empty(&work
->entry
))) {
1035 spin_unlock_irqrestore(&gcwq
->lock
, flags
);
1039 cwq
->nr_in_flight
[cwq
->work_color
]++;
1040 work_flags
= work_color_to_flags(cwq
->work_color
);
1042 if (likely(cwq
->nr_active
< cwq
->max_active
)) {
1043 trace_workqueue_activate_work(work
);
1045 worklist
= &cwq
->pool
->worklist
;
1047 work_flags
|= WORK_STRUCT_DELAYED
;
1048 worklist
= &cwq
->delayed_works
;
1051 insert_work(cwq
, work
, worklist
, work_flags
);
1053 spin_unlock_irqrestore(&gcwq
->lock
, flags
);
1057 * queue_work - queue work on a workqueue
1058 * @wq: workqueue to use
1059 * @work: work to queue
1061 * Returns 0 if @work was already on a queue, non-zero otherwise.
1063 * We queue the work to the CPU on which it was submitted, but if the CPU dies
1064 * it can be processed by another CPU.
1066 int queue_work(struct workqueue_struct
*wq
, struct work_struct
*work
)
1070 ret
= queue_work_on(get_cpu(), wq
, work
);
1075 EXPORT_SYMBOL_GPL(queue_work
);
1078 * queue_work_on - queue work on specific cpu
1079 * @cpu: CPU number to execute work on
1080 * @wq: workqueue to use
1081 * @work: work to queue
1083 * Returns 0 if @work was already on a queue, non-zero otherwise.
1085 * We queue the work to a specific CPU, the caller must ensure it
1089 queue_work_on(int cpu
, struct workqueue_struct
*wq
, struct work_struct
*work
)
1093 if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT
, work_data_bits(work
))) {
1094 __queue_work(cpu
, wq
, work
);
1099 EXPORT_SYMBOL_GPL(queue_work_on
);
1101 static void delayed_work_timer_fn(unsigned long __data
)
1103 struct delayed_work
*dwork
= (struct delayed_work
*)__data
;
1104 struct cpu_workqueue_struct
*cwq
= get_work_cwq(&dwork
->work
);
1106 __queue_work(smp_processor_id(), cwq
->wq
, &dwork
->work
);
1110 * queue_delayed_work - queue work on a workqueue after delay
1111 * @wq: workqueue to use
1112 * @dwork: delayable work to queue
1113 * @delay: number of jiffies to wait before queueing
1115 * Returns 0 if @work was already on a queue, non-zero otherwise.
1117 int queue_delayed_work(struct workqueue_struct
*wq
,
1118 struct delayed_work
*dwork
, unsigned long delay
)
1121 return queue_work(wq
, &dwork
->work
);
1123 return queue_delayed_work_on(-1, wq
, dwork
, delay
);
1125 EXPORT_SYMBOL_GPL(queue_delayed_work
);
1128 * queue_delayed_work_on - queue work on specific CPU after delay
1129 * @cpu: CPU number to execute work on
1130 * @wq: workqueue to use
1131 * @dwork: work to queue
1132 * @delay: number of jiffies to wait before queueing
1134 * Returns 0 if @work was already on a queue, non-zero otherwise.
1136 int queue_delayed_work_on(int cpu
, struct workqueue_struct
*wq
,
1137 struct delayed_work
*dwork
, unsigned long delay
)
1140 struct timer_list
*timer
= &dwork
->timer
;
1141 struct work_struct
*work
= &dwork
->work
;
1143 if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT
, work_data_bits(work
))) {
1146 BUG_ON(timer_pending(timer
));
1147 BUG_ON(!list_empty(&work
->entry
));
1149 timer_stats_timer_set_start_info(&dwork
->timer
);
1152 * This stores cwq for the moment, for the timer_fn.
1153 * Note that the work's gcwq is preserved to allow
1154 * reentrance detection for delayed works.
1156 if (!(wq
->flags
& WQ_UNBOUND
)) {
1157 struct global_cwq
*gcwq
= get_work_gcwq(work
);
1159 if (gcwq
&& gcwq
->cpu
!= WORK_CPU_UNBOUND
)
1162 lcpu
= raw_smp_processor_id();
1164 lcpu
= WORK_CPU_UNBOUND
;
1166 set_work_cwq(work
, get_cwq(lcpu
, wq
), 0);
1168 timer
->expires
= jiffies
+ delay
;
1169 timer
->data
= (unsigned long)dwork
;
1170 timer
->function
= delayed_work_timer_fn
;
1172 if (unlikely(cpu
>= 0))
1173 add_timer_on(timer
, cpu
);
1180 EXPORT_SYMBOL_GPL(queue_delayed_work_on
);
1183 * worker_enter_idle - enter idle state
1184 * @worker: worker which is entering idle state
1186 * @worker is entering idle state. Update stats and idle timer if
1190 * spin_lock_irq(gcwq->lock).
1192 static void worker_enter_idle(struct worker
*worker
)
1194 struct worker_pool
*pool
= worker
->pool
;
1195 struct global_cwq
*gcwq
= pool
->gcwq
;
1197 BUG_ON(worker
->flags
& WORKER_IDLE
);
1198 BUG_ON(!list_empty(&worker
->entry
) &&
1199 (worker
->hentry
.next
|| worker
->hentry
.pprev
));
1201 /* can't use worker_set_flags(), also called from start_worker() */
1202 worker
->flags
|= WORKER_IDLE
;
1204 worker
->last_active
= jiffies
;
1206 /* idle_list is LIFO */
1207 list_add(&worker
->entry
, &pool
->idle_list
);
1209 if (too_many_workers(pool
) && !timer_pending(&pool
->idle_timer
))
1210 mod_timer(&pool
->idle_timer
, jiffies
+ IDLE_WORKER_TIMEOUT
);
1213 * Sanity check nr_running. Because gcwq_unbind_fn() releases
1214 * gcwq->lock between setting %WORKER_UNBOUND and zapping
1215 * nr_running, the warning may trigger spuriously. Check iff
1216 * unbind is not in progress.
1218 WARN_ON_ONCE(!(gcwq
->flags
& GCWQ_DISASSOCIATED
) &&
1219 pool
->nr_workers
== pool
->nr_idle
&&
1220 atomic_read(get_pool_nr_running(pool
)));
1224 * worker_leave_idle - leave idle state
1225 * @worker: worker which is leaving idle state
1227 * @worker is leaving idle state. Update stats.
1230 * spin_lock_irq(gcwq->lock).
1232 static void worker_leave_idle(struct worker
*worker
)
1234 struct worker_pool
*pool
= worker
->pool
;
1236 BUG_ON(!(worker
->flags
& WORKER_IDLE
));
1237 worker_clr_flags(worker
, WORKER_IDLE
);
1239 list_del_init(&worker
->entry
);
1243 * worker_maybe_bind_and_lock - bind worker to its cpu if possible and lock gcwq
1246 * Works which are scheduled while the cpu is online must at least be
1247 * scheduled to a worker which is bound to the cpu so that if they are
1248 * flushed from cpu callbacks while cpu is going down, they are
1249 * guaranteed to execute on the cpu.
1251 * This function is to be used by rogue workers and rescuers to bind
1252 * themselves to the target cpu and may race with cpu going down or
1253 * coming online. kthread_bind() can't be used because it may put the
1254 * worker to already dead cpu and set_cpus_allowed_ptr() can't be used
1255 * verbatim as it's best effort and blocking and gcwq may be
1256 * [dis]associated in the meantime.
1258 * This function tries set_cpus_allowed() and locks gcwq and verifies the
1259 * binding against %GCWQ_DISASSOCIATED which is set during
1260 * %CPU_DOWN_PREPARE and cleared during %CPU_ONLINE, so if the worker
1261 * enters idle state or fetches works without dropping lock, it can
1262 * guarantee the scheduling requirement described in the first paragraph.
1265 * Might sleep. Called without any lock but returns with gcwq->lock
1269 * %true if the associated gcwq is online (@worker is successfully
1270 * bound), %false if offline.
1272 static bool worker_maybe_bind_and_lock(struct worker
*worker
)
1273 __acquires(&gcwq
->lock
)
1275 struct global_cwq
*gcwq
= worker
->pool
->gcwq
;
1276 struct task_struct
*task
= worker
->task
;
1280 * The following call may fail, succeed or succeed
1281 * without actually migrating the task to the cpu if
1282 * it races with cpu hotunplug operation. Verify
1283 * against GCWQ_DISASSOCIATED.
1285 if (!(gcwq
->flags
& GCWQ_DISASSOCIATED
))
1286 set_cpus_allowed_ptr(task
, get_cpu_mask(gcwq
->cpu
));
1288 spin_lock_irq(&gcwq
->lock
);
1289 if (gcwq
->flags
& GCWQ_DISASSOCIATED
)
1291 if (task_cpu(task
) == gcwq
->cpu
&&
1292 cpumask_equal(¤t
->cpus_allowed
,
1293 get_cpu_mask(gcwq
->cpu
)))
1295 spin_unlock_irq(&gcwq
->lock
);
1298 * We've raced with CPU hot[un]plug. Give it a breather
1299 * and retry migration. cond_resched() is required here;
1300 * otherwise, we might deadlock against cpu_stop trying to
1301 * bring down the CPU on non-preemptive kernel.
1308 struct idle_rebind
{
1309 int cnt
; /* # workers to be rebound */
1310 struct completion done
; /* all workers rebound */
1314 * Rebind an idle @worker to its CPU. During CPU onlining, this has to
1315 * happen synchronously for idle workers. worker_thread() will test
1316 * %WORKER_REBIND before leaving idle and call this function.
1318 static void idle_worker_rebind(struct worker
*worker
)
1320 struct global_cwq
*gcwq
= worker
->pool
->gcwq
;
1322 /* CPU must be online at this point */
1323 WARN_ON(!worker_maybe_bind_and_lock(worker
));
1324 if (!--worker
->idle_rebind
->cnt
)
1325 complete(&worker
->idle_rebind
->done
);
1326 spin_unlock_irq(&worker
->pool
->gcwq
->lock
);
1328 /* we did our part, wait for rebind_workers() to finish up */
1329 wait_event(gcwq
->rebind_hold
, !(worker
->flags
& WORKER_REBIND
));
1332 * rebind_workers() shouldn't finish until all workers passed the
1333 * above WORKER_REBIND wait. Tell it when done.
1335 spin_lock_irq(&worker
->pool
->gcwq
->lock
);
1336 if (!--worker
->idle_rebind
->cnt
)
1337 complete(&worker
->idle_rebind
->done
);
1338 spin_unlock_irq(&worker
->pool
->gcwq
->lock
);
1342 * Function for @worker->rebind.work used to rebind unbound busy workers to
1343 * the associated cpu which is coming back online. This is scheduled by
1344 * cpu up but can race with other cpu hotplug operations and may be
1345 * executed twice without intervening cpu down.
1347 static void busy_worker_rebind_fn(struct work_struct
*work
)
1349 struct worker
*worker
= container_of(work
, struct worker
, rebind_work
);
1350 struct global_cwq
*gcwq
= worker
->pool
->gcwq
;
1352 worker_maybe_bind_and_lock(worker
);
1355 * %WORKER_REBIND must be cleared even if the above binding failed;
1356 * otherwise, we may confuse the next CPU_UP cycle or oops / get
1357 * stuck by calling idle_worker_rebind() prematurely. If CPU went
1358 * down again inbetween, %WORKER_UNBOUND would be set, so clearing
1359 * %WORKER_REBIND is always safe.
1361 worker_clr_flags(worker
, WORKER_REBIND
);
1363 spin_unlock_irq(&gcwq
->lock
);
1367 * rebind_workers - rebind all workers of a gcwq to the associated CPU
1368 * @gcwq: gcwq of interest
1370 * @gcwq->cpu is coming online. Rebind all workers to the CPU. Rebinding
1371 * is different for idle and busy ones.
1373 * The idle ones should be rebound synchronously and idle rebinding should
1374 * be complete before any worker starts executing work items with
1375 * concurrency management enabled; otherwise, scheduler may oops trying to
1376 * wake up non-local idle worker from wq_worker_sleeping().
1378 * This is achieved by repeatedly requesting rebinding until all idle
1379 * workers are known to have been rebound under @gcwq->lock and holding all
1380 * idle workers from becoming busy until idle rebinding is complete.
1382 * Once idle workers are rebound, busy workers can be rebound as they
1383 * finish executing their current work items. Queueing the rebind work at
1384 * the head of their scheduled lists is enough. Note that nr_running will
1385 * be properbly bumped as busy workers rebind.
1387 * On return, all workers are guaranteed to either be bound or have rebind
1388 * work item scheduled.
1390 static void rebind_workers(struct global_cwq
*gcwq
)
1391 __releases(&gcwq
->lock
) __acquires(&gcwq
->lock
)
1393 struct idle_rebind idle_rebind
;
1394 struct worker_pool
*pool
;
1395 struct worker
*worker
;
1396 struct hlist_node
*pos
;
1399 lockdep_assert_held(&gcwq
->lock
);
1401 for_each_worker_pool(pool
, gcwq
)
1402 lockdep_assert_held(&pool
->manager_mutex
);
1405 * Rebind idle workers. Interlocked both ways. We wait for
1406 * workers to rebind via @idle_rebind.done. Workers will wait for
1407 * us to finish up by watching %WORKER_REBIND.
1409 init_completion(&idle_rebind
.done
);
1411 idle_rebind
.cnt
= 1;
1412 INIT_COMPLETION(idle_rebind
.done
);
1414 /* set REBIND and kick idle ones, we'll wait for these later */
1415 for_each_worker_pool(pool
, gcwq
) {
1416 list_for_each_entry(worker
, &pool
->idle_list
, entry
) {
1417 unsigned long worker_flags
= worker
->flags
;
1419 if (worker
->flags
& WORKER_REBIND
)
1422 /* morph UNBOUND to REBIND atomically */
1423 worker_flags
&= ~WORKER_UNBOUND
;
1424 worker_flags
|= WORKER_REBIND
;
1425 ACCESS_ONCE(worker
->flags
) = worker_flags
;
1428 worker
->idle_rebind
= &idle_rebind
;
1430 /* worker_thread() will call idle_worker_rebind() */
1431 wake_up_process(worker
->task
);
1435 if (--idle_rebind
.cnt
) {
1436 spin_unlock_irq(&gcwq
->lock
);
1437 wait_for_completion(&idle_rebind
.done
);
1438 spin_lock_irq(&gcwq
->lock
);
1439 /* busy ones might have become idle while waiting, retry */
1443 /* all idle workers are rebound, rebind busy workers */
1444 for_each_busy_worker(worker
, i
, pos
, gcwq
) {
1445 struct work_struct
*rebind_work
= &worker
->rebind_work
;
1446 unsigned long worker_flags
= worker
->flags
;
1448 /* morph UNBOUND to REBIND atomically */
1449 worker_flags
&= ~WORKER_UNBOUND
;
1450 worker_flags
|= WORKER_REBIND
;
1451 ACCESS_ONCE(worker
->flags
) = worker_flags
;
1453 if (test_and_set_bit(WORK_STRUCT_PENDING_BIT
,
1454 work_data_bits(rebind_work
)))
1457 /* wq doesn't matter, use the default one */
1458 debug_work_activate(rebind_work
);
1459 insert_work(get_cwq(gcwq
->cpu
, system_wq
), rebind_work
,
1460 worker
->scheduled
.next
,
1461 work_color_to_flags(WORK_NO_COLOR
));
1465 * All idle workers are rebound and waiting for %WORKER_REBIND to
1466 * be cleared inside idle_worker_rebind(). Clear and release.
1467 * Clearing %WORKER_REBIND from this foreign context is safe
1468 * because these workers are still guaranteed to be idle.
1470 * We need to make sure all idle workers passed WORKER_REBIND wait
1471 * in idle_worker_rebind() before returning; otherwise, workers can
1472 * get stuck at the wait if hotplug cycle repeats.
1474 idle_rebind
.cnt
= 1;
1475 INIT_COMPLETION(idle_rebind
.done
);
1477 for_each_worker_pool(pool
, gcwq
) {
1478 list_for_each_entry(worker
, &pool
->idle_list
, entry
) {
1479 worker
->flags
&= ~WORKER_REBIND
;
1484 wake_up_all(&gcwq
->rebind_hold
);
1486 if (--idle_rebind
.cnt
) {
1487 spin_unlock_irq(&gcwq
->lock
);
1488 wait_for_completion(&idle_rebind
.done
);
1489 spin_lock_irq(&gcwq
->lock
);
1493 static struct worker
*alloc_worker(void)
1495 struct worker
*worker
;
1497 worker
= kzalloc(sizeof(*worker
), GFP_KERNEL
);
1499 INIT_LIST_HEAD(&worker
->entry
);
1500 INIT_LIST_HEAD(&worker
->scheduled
);
1501 INIT_WORK(&worker
->rebind_work
, busy_worker_rebind_fn
);
1502 /* on creation a worker is in !idle && prep state */
1503 worker
->flags
= WORKER_PREP
;
1509 * create_worker - create a new workqueue worker
1510 * @pool: pool the new worker will belong to
1512 * Create a new worker which is bound to @pool. The returned worker
1513 * can be started by calling start_worker() or destroyed using
1517 * Might sleep. Does GFP_KERNEL allocations.
1520 * Pointer to the newly created worker.
1522 static struct worker
*create_worker(struct worker_pool
*pool
)
1524 struct global_cwq
*gcwq
= pool
->gcwq
;
1525 const char *pri
= worker_pool_pri(pool
) ? "H" : "";
1526 struct worker
*worker
= NULL
;
1529 spin_lock_irq(&gcwq
->lock
);
1530 while (ida_get_new(&pool
->worker_ida
, &id
)) {
1531 spin_unlock_irq(&gcwq
->lock
);
1532 if (!ida_pre_get(&pool
->worker_ida
, GFP_KERNEL
))
1534 spin_lock_irq(&gcwq
->lock
);
1536 spin_unlock_irq(&gcwq
->lock
);
1538 worker
= alloc_worker();
1542 worker
->pool
= pool
;
1545 if (gcwq
->cpu
!= WORK_CPU_UNBOUND
)
1546 worker
->task
= kthread_create_on_node(worker_thread
,
1547 worker
, cpu_to_node(gcwq
->cpu
),
1548 "kworker/%u:%d%s", gcwq
->cpu
, id
, pri
);
1550 worker
->task
= kthread_create(worker_thread
, worker
,
1551 "kworker/u:%d%s", id
, pri
);
1552 if (IS_ERR(worker
->task
))
1555 if (worker_pool_pri(pool
))
1556 set_user_nice(worker
->task
, HIGHPRI_NICE_LEVEL
);
1559 * Determine CPU binding of the new worker depending on
1560 * %GCWQ_DISASSOCIATED. The caller is responsible for ensuring the
1561 * flag remains stable across this function. See the comments
1562 * above the flag definition for details.
1564 * As an unbound worker may later become a regular one if CPU comes
1565 * online, make sure every worker has %PF_THREAD_BOUND set.
1567 if (!(gcwq
->flags
& GCWQ_DISASSOCIATED
)) {
1568 kthread_bind(worker
->task
, gcwq
->cpu
);
1570 worker
->task
->flags
|= PF_THREAD_BOUND
;
1571 worker
->flags
|= WORKER_UNBOUND
;
1577 spin_lock_irq(&gcwq
->lock
);
1578 ida_remove(&pool
->worker_ida
, id
);
1579 spin_unlock_irq(&gcwq
->lock
);
1586 * start_worker - start a newly created worker
1587 * @worker: worker to start
1589 * Make the gcwq aware of @worker and start it.
1592 * spin_lock_irq(gcwq->lock).
1594 static void start_worker(struct worker
*worker
)
1596 worker
->flags
|= WORKER_STARTED
;
1597 worker
->pool
->nr_workers
++;
1598 worker_enter_idle(worker
);
1599 wake_up_process(worker
->task
);
1603 * destroy_worker - destroy a workqueue worker
1604 * @worker: worker to be destroyed
1606 * Destroy @worker and adjust @gcwq stats accordingly.
1609 * spin_lock_irq(gcwq->lock) which is released and regrabbed.
1611 static void destroy_worker(struct worker
*worker
)
1613 struct worker_pool
*pool
= worker
->pool
;
1614 struct global_cwq
*gcwq
= pool
->gcwq
;
1615 int id
= worker
->id
;
1617 /* sanity check frenzy */
1618 BUG_ON(worker
->current_work
);
1619 BUG_ON(!list_empty(&worker
->scheduled
));
1621 if (worker
->flags
& WORKER_STARTED
)
1623 if (worker
->flags
& WORKER_IDLE
)
1626 list_del_init(&worker
->entry
);
1627 worker
->flags
|= WORKER_DIE
;
1629 spin_unlock_irq(&gcwq
->lock
);
1631 kthread_stop(worker
->task
);
1634 spin_lock_irq(&gcwq
->lock
);
1635 ida_remove(&pool
->worker_ida
, id
);
1638 static void idle_worker_timeout(unsigned long __pool
)
1640 struct worker_pool
*pool
= (void *)__pool
;
1641 struct global_cwq
*gcwq
= pool
->gcwq
;
1643 spin_lock_irq(&gcwq
->lock
);
1645 if (too_many_workers(pool
)) {
1646 struct worker
*worker
;
1647 unsigned long expires
;
1649 /* idle_list is kept in LIFO order, check the last one */
1650 worker
= list_entry(pool
->idle_list
.prev
, struct worker
, entry
);
1651 expires
= worker
->last_active
+ IDLE_WORKER_TIMEOUT
;
1653 if (time_before(jiffies
, expires
))
1654 mod_timer(&pool
->idle_timer
, expires
);
1656 /* it's been idle for too long, wake up manager */
1657 pool
->flags
|= POOL_MANAGE_WORKERS
;
1658 wake_up_worker(pool
);
1662 spin_unlock_irq(&gcwq
->lock
);
1665 static bool send_mayday(struct work_struct
*work
)
1667 struct cpu_workqueue_struct
*cwq
= get_work_cwq(work
);
1668 struct workqueue_struct
*wq
= cwq
->wq
;
1671 if (!(wq
->flags
& WQ_RESCUER
))
1674 /* mayday mayday mayday */
1675 cpu
= cwq
->pool
->gcwq
->cpu
;
1676 /* WORK_CPU_UNBOUND can't be set in cpumask, use cpu 0 instead */
1677 if (cpu
== WORK_CPU_UNBOUND
)
1679 if (!mayday_test_and_set_cpu(cpu
, wq
->mayday_mask
))
1680 wake_up_process(wq
->rescuer
->task
);
1684 static void gcwq_mayday_timeout(unsigned long __pool
)
1686 struct worker_pool
*pool
= (void *)__pool
;
1687 struct global_cwq
*gcwq
= pool
->gcwq
;
1688 struct work_struct
*work
;
1690 spin_lock_irq(&gcwq
->lock
);
1692 if (need_to_create_worker(pool
)) {
1694 * We've been trying to create a new worker but
1695 * haven't been successful. We might be hitting an
1696 * allocation deadlock. Send distress signals to
1699 list_for_each_entry(work
, &pool
->worklist
, entry
)
1703 spin_unlock_irq(&gcwq
->lock
);
1705 mod_timer(&pool
->mayday_timer
, jiffies
+ MAYDAY_INTERVAL
);
1709 * maybe_create_worker - create a new worker if necessary
1710 * @pool: pool to create a new worker for
1712 * Create a new worker for @pool if necessary. @pool is guaranteed to
1713 * have at least one idle worker on return from this function. If
1714 * creating a new worker takes longer than MAYDAY_INTERVAL, mayday is
1715 * sent to all rescuers with works scheduled on @pool to resolve
1716 * possible allocation deadlock.
1718 * On return, need_to_create_worker() is guaranteed to be false and
1719 * may_start_working() true.
1722 * spin_lock_irq(gcwq->lock) which may be released and regrabbed
1723 * multiple times. Does GFP_KERNEL allocations. Called only from
1727 * false if no action was taken and gcwq->lock stayed locked, true
1730 static bool maybe_create_worker(struct worker_pool
*pool
)
1731 __releases(&gcwq
->lock
)
1732 __acquires(&gcwq
->lock
)
1734 struct global_cwq
*gcwq
= pool
->gcwq
;
1736 if (!need_to_create_worker(pool
))
1739 spin_unlock_irq(&gcwq
->lock
);
1741 /* if we don't make progress in MAYDAY_INITIAL_TIMEOUT, call for help */
1742 mod_timer(&pool
->mayday_timer
, jiffies
+ MAYDAY_INITIAL_TIMEOUT
);
1745 struct worker
*worker
;
1747 worker
= create_worker(pool
);
1749 del_timer_sync(&pool
->mayday_timer
);
1750 spin_lock_irq(&gcwq
->lock
);
1751 start_worker(worker
);
1752 BUG_ON(need_to_create_worker(pool
));
1756 if (!need_to_create_worker(pool
))
1759 __set_current_state(TASK_INTERRUPTIBLE
);
1760 schedule_timeout(CREATE_COOLDOWN
);
1762 if (!need_to_create_worker(pool
))
1766 del_timer_sync(&pool
->mayday_timer
);
1767 spin_lock_irq(&gcwq
->lock
);
1768 if (need_to_create_worker(pool
))
1774 * maybe_destroy_worker - destroy workers which have been idle for a while
1775 * @pool: pool to destroy workers for
1777 * Destroy @pool workers which have been idle for longer than
1778 * IDLE_WORKER_TIMEOUT.
1781 * spin_lock_irq(gcwq->lock) which may be released and regrabbed
1782 * multiple times. Called only from manager.
1785 * false if no action was taken and gcwq->lock stayed locked, true
1788 static bool maybe_destroy_workers(struct worker_pool
*pool
)
1792 while (too_many_workers(pool
)) {
1793 struct worker
*worker
;
1794 unsigned long expires
;
1796 worker
= list_entry(pool
->idle_list
.prev
, struct worker
, entry
);
1797 expires
= worker
->last_active
+ IDLE_WORKER_TIMEOUT
;
1799 if (time_before(jiffies
, expires
)) {
1800 mod_timer(&pool
->idle_timer
, expires
);
1804 destroy_worker(worker
);
1812 * manage_workers - manage worker pool
1815 * Assume the manager role and manage gcwq worker pool @worker belongs
1816 * to. At any given time, there can be only zero or one manager per
1817 * gcwq. The exclusion is handled automatically by this function.
1819 * The caller can safely start processing works on false return. On
1820 * true return, it's guaranteed that need_to_create_worker() is false
1821 * and may_start_working() is true.
1824 * spin_lock_irq(gcwq->lock) which may be released and regrabbed
1825 * multiple times. Does GFP_KERNEL allocations.
1828 * false if no action was taken and gcwq->lock stayed locked, true if
1829 * some action was taken.
1831 static bool manage_workers(struct worker
*worker
)
1833 struct worker_pool
*pool
= worker
->pool
;
1836 if (pool
->flags
& POOL_MANAGING_WORKERS
)
1839 pool
->flags
|= POOL_MANAGING_WORKERS
;
1842 * To simplify both worker management and CPU hotplug, hold off
1843 * management while hotplug is in progress. CPU hotplug path can't
1844 * grab %POOL_MANAGING_WORKERS to achieve this because that can
1845 * lead to idle worker depletion (all become busy thinking someone
1846 * else is managing) which in turn can result in deadlock under
1847 * extreme circumstances. Use @pool->manager_mutex to synchronize
1848 * manager against CPU hotplug.
1850 * manager_mutex would always be free unless CPU hotplug is in
1851 * progress. trylock first without dropping @gcwq->lock.
1853 if (unlikely(!mutex_trylock(&pool
->manager_mutex
))) {
1854 spin_unlock_irq(&pool
->gcwq
->lock
);
1855 mutex_lock(&pool
->manager_mutex
);
1857 * CPU hotplug could have happened while we were waiting
1858 * for manager_mutex. Hotplug itself can't handle us
1859 * because manager isn't either on idle or busy list, and
1860 * @gcwq's state and ours could have deviated.
1862 * As hotplug is now excluded via manager_mutex, we can
1863 * simply try to bind. It will succeed or fail depending
1864 * on @gcwq's current state. Try it and adjust
1865 * %WORKER_UNBOUND accordingly.
1867 if (worker_maybe_bind_and_lock(worker
))
1868 worker
->flags
&= ~WORKER_UNBOUND
;
1870 worker
->flags
|= WORKER_UNBOUND
;
1875 pool
->flags
&= ~POOL_MANAGE_WORKERS
;
1878 * Destroy and then create so that may_start_working() is true
1881 ret
|= maybe_destroy_workers(pool
);
1882 ret
|= maybe_create_worker(pool
);
1884 pool
->flags
&= ~POOL_MANAGING_WORKERS
;
1885 mutex_unlock(&pool
->manager_mutex
);
1890 * move_linked_works - move linked works to a list
1891 * @work: start of series of works to be scheduled
1892 * @head: target list to append @work to
1893 * @nextp: out paramter for nested worklist walking
1895 * Schedule linked works starting from @work to @head. Work series to
1896 * be scheduled starts at @work and includes any consecutive work with
1897 * WORK_STRUCT_LINKED set in its predecessor.
1899 * If @nextp is not NULL, it's updated to point to the next work of
1900 * the last scheduled work. This allows move_linked_works() to be
1901 * nested inside outer list_for_each_entry_safe().
1904 * spin_lock_irq(gcwq->lock).
1906 static void move_linked_works(struct work_struct
*work
, struct list_head
*head
,
1907 struct work_struct
**nextp
)
1909 struct work_struct
*n
;
1912 * Linked worklist will always end before the end of the list,
1913 * use NULL for list head.
1915 list_for_each_entry_safe_from(work
, n
, NULL
, entry
) {
1916 list_move_tail(&work
->entry
, head
);
1917 if (!(*work_data_bits(work
) & WORK_STRUCT_LINKED
))
1922 * If we're already inside safe list traversal and have moved
1923 * multiple works to the scheduled queue, the next position
1924 * needs to be updated.
1930 static void cwq_activate_first_delayed(struct cpu_workqueue_struct
*cwq
)
1932 struct work_struct
*work
= list_first_entry(&cwq
->delayed_works
,
1933 struct work_struct
, entry
);
1935 trace_workqueue_activate_work(work
);
1936 move_linked_works(work
, &cwq
->pool
->worklist
, NULL
);
1937 __clear_bit(WORK_STRUCT_DELAYED_BIT
, work_data_bits(work
));
1942 * cwq_dec_nr_in_flight - decrement cwq's nr_in_flight
1943 * @cwq: cwq of interest
1944 * @color: color of work which left the queue
1945 * @delayed: for a delayed work
1947 * A work either has completed or is removed from pending queue,
1948 * decrement nr_in_flight of its cwq and handle workqueue flushing.
1951 * spin_lock_irq(gcwq->lock).
1953 static void cwq_dec_nr_in_flight(struct cpu_workqueue_struct
*cwq
, int color
,
1956 /* ignore uncolored works */
1957 if (color
== WORK_NO_COLOR
)
1960 cwq
->nr_in_flight
[color
]--;
1964 if (!list_empty(&cwq
->delayed_works
)) {
1965 /* one down, submit a delayed one */
1966 if (cwq
->nr_active
< cwq
->max_active
)
1967 cwq_activate_first_delayed(cwq
);
1971 /* is flush in progress and are we at the flushing tip? */
1972 if (likely(cwq
->flush_color
!= color
))
1975 /* are there still in-flight works? */
1976 if (cwq
->nr_in_flight
[color
])
1979 /* this cwq is done, clear flush_color */
1980 cwq
->flush_color
= -1;
1983 * If this was the last cwq, wake up the first flusher. It
1984 * will handle the rest.
1986 if (atomic_dec_and_test(&cwq
->wq
->nr_cwqs_to_flush
))
1987 complete(&cwq
->wq
->first_flusher
->done
);
1991 * process_one_work - process single work
1993 * @work: work to process
1995 * Process @work. This function contains all the logics necessary to
1996 * process a single work including synchronization against and
1997 * interaction with other workers on the same cpu, queueing and
1998 * flushing. As long as context requirement is met, any worker can
1999 * call this function to process a work.
2002 * spin_lock_irq(gcwq->lock) which is released and regrabbed.
2004 static void process_one_work(struct worker
*worker
, struct work_struct
*work
)
2005 __releases(&gcwq
->lock
)
2006 __acquires(&gcwq
->lock
)
2008 struct cpu_workqueue_struct
*cwq
= get_work_cwq(work
);
2009 struct worker_pool
*pool
= worker
->pool
;
2010 struct global_cwq
*gcwq
= pool
->gcwq
;
2011 struct hlist_head
*bwh
= busy_worker_head(gcwq
, work
);
2012 bool cpu_intensive
= cwq
->wq
->flags
& WQ_CPU_INTENSIVE
;
2013 work_func_t f
= work
->func
;
2015 struct worker
*collision
;
2016 #ifdef CONFIG_LOCKDEP
2018 * It is permissible to free the struct work_struct from
2019 * inside the function that is called from it, this we need to
2020 * take into account for lockdep too. To avoid bogus "held
2021 * lock freed" warnings as well as problems when looking into
2022 * work->lockdep_map, make a copy and use that here.
2024 struct lockdep_map lockdep_map
;
2026 lockdep_copy_map(&lockdep_map
, &work
->lockdep_map
);
2029 * Ensure we're on the correct CPU. DISASSOCIATED test is
2030 * necessary to avoid spurious warnings from rescuers servicing the
2031 * unbound or a disassociated gcwq.
2033 WARN_ON_ONCE(!(worker
->flags
& (WORKER_UNBOUND
| WORKER_REBIND
)) &&
2034 !(gcwq
->flags
& GCWQ_DISASSOCIATED
) &&
2035 raw_smp_processor_id() != gcwq
->cpu
);
2038 * A single work shouldn't be executed concurrently by
2039 * multiple workers on a single cpu. Check whether anyone is
2040 * already processing the work. If so, defer the work to the
2041 * currently executing one.
2043 collision
= __find_worker_executing_work(gcwq
, bwh
, work
);
2044 if (unlikely(collision
)) {
2045 move_linked_works(work
, &collision
->scheduled
, NULL
);
2049 /* claim and process */
2050 debug_work_deactivate(work
);
2051 hlist_add_head(&worker
->hentry
, bwh
);
2052 worker
->current_work
= work
;
2053 worker
->current_cwq
= cwq
;
2054 work_color
= get_work_color(work
);
2056 /* record the current cpu number in the work data and dequeue */
2057 set_work_cpu(work
, gcwq
->cpu
);
2058 list_del_init(&work
->entry
);
2061 * CPU intensive works don't participate in concurrency
2062 * management. They're the scheduler's responsibility.
2064 if (unlikely(cpu_intensive
))
2065 worker_set_flags(worker
, WORKER_CPU_INTENSIVE
, true);
2068 * Unbound gcwq isn't concurrency managed and work items should be
2069 * executed ASAP. Wake up another worker if necessary.
2071 if ((worker
->flags
& WORKER_UNBOUND
) && need_more_worker(pool
))
2072 wake_up_worker(pool
);
2074 spin_unlock_irq(&gcwq
->lock
);
2076 work_clear_pending(work
);
2077 lock_map_acquire_read(&cwq
->wq
->lockdep_map
);
2078 lock_map_acquire(&lockdep_map
);
2079 trace_workqueue_execute_start(work
);
2082 * While we must be careful to not use "work" after this, the trace
2083 * point will only record its address.
2085 trace_workqueue_execute_end(work
);
2086 lock_map_release(&lockdep_map
);
2087 lock_map_release(&cwq
->wq
->lockdep_map
);
2089 if (unlikely(in_atomic() || lockdep_depth(current
) > 0)) {
2090 printk(KERN_ERR
"BUG: workqueue leaked lock or atomic: "
2092 current
->comm
, preempt_count(), task_pid_nr(current
));
2093 printk(KERN_ERR
" last function: ");
2094 print_symbol("%s\n", (unsigned long)f
);
2095 debug_show_held_locks(current
);
2099 spin_lock_irq(&gcwq
->lock
);
2101 /* clear cpu intensive status */
2102 if (unlikely(cpu_intensive
))
2103 worker_clr_flags(worker
, WORKER_CPU_INTENSIVE
);
2105 /* we're done with it, release */
2106 hlist_del_init(&worker
->hentry
);
2107 worker
->current_work
= NULL
;
2108 worker
->current_cwq
= NULL
;
2109 cwq_dec_nr_in_flight(cwq
, work_color
, false);
2113 * process_scheduled_works - process scheduled works
2116 * Process all scheduled works. Please note that the scheduled list
2117 * may change while processing a work, so this function repeatedly
2118 * fetches a work from the top and executes it.
2121 * spin_lock_irq(gcwq->lock) which may be released and regrabbed
2124 static void process_scheduled_works(struct worker
*worker
)
2126 while (!list_empty(&worker
->scheduled
)) {
2127 struct work_struct
*work
= list_first_entry(&worker
->scheduled
,
2128 struct work_struct
, entry
);
2129 process_one_work(worker
, work
);
2134 * worker_thread - the worker thread function
2137 * The gcwq worker thread function. There's a single dynamic pool of
2138 * these per each cpu. These workers process all works regardless of
2139 * their specific target workqueue. The only exception is works which
2140 * belong to workqueues with a rescuer which will be explained in
2143 static int worker_thread(void *__worker
)
2145 struct worker
*worker
= __worker
;
2146 struct worker_pool
*pool
= worker
->pool
;
2147 struct global_cwq
*gcwq
= pool
->gcwq
;
2149 /* tell the scheduler that this is a workqueue worker */
2150 worker
->task
->flags
|= PF_WQ_WORKER
;
2152 spin_lock_irq(&gcwq
->lock
);
2155 * DIE can be set only while idle and REBIND set while busy has
2156 * @worker->rebind_work scheduled. Checking here is enough.
2158 if (unlikely(worker
->flags
& (WORKER_REBIND
| WORKER_DIE
))) {
2159 spin_unlock_irq(&gcwq
->lock
);
2161 if (worker
->flags
& WORKER_DIE
) {
2162 worker
->task
->flags
&= ~PF_WQ_WORKER
;
2166 idle_worker_rebind(worker
);
2170 worker_leave_idle(worker
);
2172 /* no more worker necessary? */
2173 if (!need_more_worker(pool
))
2176 /* do we need to manage? */
2177 if (unlikely(!may_start_working(pool
)) && manage_workers(worker
))
2181 * ->scheduled list can only be filled while a worker is
2182 * preparing to process a work or actually processing it.
2183 * Make sure nobody diddled with it while I was sleeping.
2185 BUG_ON(!list_empty(&worker
->scheduled
));
2188 * When control reaches this point, we're guaranteed to have
2189 * at least one idle worker or that someone else has already
2190 * assumed the manager role.
2192 worker_clr_flags(worker
, WORKER_PREP
);
2195 struct work_struct
*work
=
2196 list_first_entry(&pool
->worklist
,
2197 struct work_struct
, entry
);
2199 if (likely(!(*work_data_bits(work
) & WORK_STRUCT_LINKED
))) {
2200 /* optimization path, not strictly necessary */
2201 process_one_work(worker
, work
);
2202 if (unlikely(!list_empty(&worker
->scheduled
)))
2203 process_scheduled_works(worker
);
2205 move_linked_works(work
, &worker
->scheduled
, NULL
);
2206 process_scheduled_works(worker
);
2208 } while (keep_working(pool
));
2210 worker_set_flags(worker
, WORKER_PREP
, false);
2212 if (unlikely(need_to_manage_workers(pool
)) && manage_workers(worker
))
2216 * gcwq->lock is held and there's no work to process and no
2217 * need to manage, sleep. Workers are woken up only while
2218 * holding gcwq->lock or from local cpu, so setting the
2219 * current state before releasing gcwq->lock is enough to
2220 * prevent losing any event.
2222 worker_enter_idle(worker
);
2223 __set_current_state(TASK_INTERRUPTIBLE
);
2224 spin_unlock_irq(&gcwq
->lock
);
2230 * rescuer_thread - the rescuer thread function
2231 * @__wq: the associated workqueue
2233 * Workqueue rescuer thread function. There's one rescuer for each
2234 * workqueue which has WQ_RESCUER set.
2236 * Regular work processing on a gcwq may block trying to create a new
2237 * worker which uses GFP_KERNEL allocation which has slight chance of
2238 * developing into deadlock if some works currently on the same queue
2239 * need to be processed to satisfy the GFP_KERNEL allocation. This is
2240 * the problem rescuer solves.
2242 * When such condition is possible, the gcwq summons rescuers of all
2243 * workqueues which have works queued on the gcwq and let them process
2244 * those works so that forward progress can be guaranteed.
2246 * This should happen rarely.
2248 static int rescuer_thread(void *__wq
)
2250 struct workqueue_struct
*wq
= __wq
;
2251 struct worker
*rescuer
= wq
->rescuer
;
2252 struct list_head
*scheduled
= &rescuer
->scheduled
;
2253 bool is_unbound
= wq
->flags
& WQ_UNBOUND
;
2256 set_user_nice(current
, RESCUER_NICE_LEVEL
);
2258 set_current_state(TASK_INTERRUPTIBLE
);
2260 if (kthread_should_stop())
2264 * See whether any cpu is asking for help. Unbounded
2265 * workqueues use cpu 0 in mayday_mask for CPU_UNBOUND.
2267 for_each_mayday_cpu(cpu
, wq
->mayday_mask
) {
2268 unsigned int tcpu
= is_unbound
? WORK_CPU_UNBOUND
: cpu
;
2269 struct cpu_workqueue_struct
*cwq
= get_cwq(tcpu
, wq
);
2270 struct worker_pool
*pool
= cwq
->pool
;
2271 struct global_cwq
*gcwq
= pool
->gcwq
;
2272 struct work_struct
*work
, *n
;
2274 __set_current_state(TASK_RUNNING
);
2275 mayday_clear_cpu(cpu
, wq
->mayday_mask
);
2277 /* migrate to the target cpu if possible */
2278 rescuer
->pool
= pool
;
2279 worker_maybe_bind_and_lock(rescuer
);
2282 * Slurp in all works issued via this workqueue and
2285 BUG_ON(!list_empty(&rescuer
->scheduled
));
2286 list_for_each_entry_safe(work
, n
, &pool
->worklist
, entry
)
2287 if (get_work_cwq(work
) == cwq
)
2288 move_linked_works(work
, scheduled
, &n
);
2290 process_scheduled_works(rescuer
);
2293 * Leave this gcwq. If keep_working() is %true, notify a
2294 * regular worker; otherwise, we end up with 0 concurrency
2295 * and stalling the execution.
2297 if (keep_working(pool
))
2298 wake_up_worker(pool
);
2300 spin_unlock_irq(&gcwq
->lock
);
2308 struct work_struct work
;
2309 struct completion done
;
2312 static void wq_barrier_func(struct work_struct
*work
)
2314 struct wq_barrier
*barr
= container_of(work
, struct wq_barrier
, work
);
2315 complete(&barr
->done
);
2319 * insert_wq_barrier - insert a barrier work
2320 * @cwq: cwq to insert barrier into
2321 * @barr: wq_barrier to insert
2322 * @target: target work to attach @barr to
2323 * @worker: worker currently executing @target, NULL if @target is not executing
2325 * @barr is linked to @target such that @barr is completed only after
2326 * @target finishes execution. Please note that the ordering
2327 * guarantee is observed only with respect to @target and on the local
2330 * Currently, a queued barrier can't be canceled. This is because
2331 * try_to_grab_pending() can't determine whether the work to be
2332 * grabbed is at the head of the queue and thus can't clear LINKED
2333 * flag of the previous work while there must be a valid next work
2334 * after a work with LINKED flag set.
2336 * Note that when @worker is non-NULL, @target may be modified
2337 * underneath us, so we can't reliably determine cwq from @target.
2340 * spin_lock_irq(gcwq->lock).
2342 static void insert_wq_barrier(struct cpu_workqueue_struct
*cwq
,
2343 struct wq_barrier
*barr
,
2344 struct work_struct
*target
, struct worker
*worker
)
2346 struct list_head
*head
;
2347 unsigned int linked
= 0;
2350 * debugobject calls are safe here even with gcwq->lock locked
2351 * as we know for sure that this will not trigger any of the
2352 * checks and call back into the fixup functions where we
2355 INIT_WORK_ONSTACK(&barr
->work
, wq_barrier_func
);
2356 __set_bit(WORK_STRUCT_PENDING_BIT
, work_data_bits(&barr
->work
));
2357 init_completion(&barr
->done
);
2360 * If @target is currently being executed, schedule the
2361 * barrier to the worker; otherwise, put it after @target.
2364 head
= worker
->scheduled
.next
;
2366 unsigned long *bits
= work_data_bits(target
);
2368 head
= target
->entry
.next
;
2369 /* there can already be other linked works, inherit and set */
2370 linked
= *bits
& WORK_STRUCT_LINKED
;
2371 __set_bit(WORK_STRUCT_LINKED_BIT
, bits
);
2374 debug_work_activate(&barr
->work
);
2375 insert_work(cwq
, &barr
->work
, head
,
2376 work_color_to_flags(WORK_NO_COLOR
) | linked
);
2380 * flush_workqueue_prep_cwqs - prepare cwqs for workqueue flushing
2381 * @wq: workqueue being flushed
2382 * @flush_color: new flush color, < 0 for no-op
2383 * @work_color: new work color, < 0 for no-op
2385 * Prepare cwqs for workqueue flushing.
2387 * If @flush_color is non-negative, flush_color on all cwqs should be
2388 * -1. If no cwq has in-flight commands at the specified color, all
2389 * cwq->flush_color's stay at -1 and %false is returned. If any cwq
2390 * has in flight commands, its cwq->flush_color is set to
2391 * @flush_color, @wq->nr_cwqs_to_flush is updated accordingly, cwq
2392 * wakeup logic is armed and %true is returned.
2394 * The caller should have initialized @wq->first_flusher prior to
2395 * calling this function with non-negative @flush_color. If
2396 * @flush_color is negative, no flush color update is done and %false
2399 * If @work_color is non-negative, all cwqs should have the same
2400 * work_color which is previous to @work_color and all will be
2401 * advanced to @work_color.
2404 * mutex_lock(wq->flush_mutex).
2407 * %true if @flush_color >= 0 and there's something to flush. %false
2410 static bool flush_workqueue_prep_cwqs(struct workqueue_struct
*wq
,
2411 int flush_color
, int work_color
)
2416 if (flush_color
>= 0) {
2417 BUG_ON(atomic_read(&wq
->nr_cwqs_to_flush
));
2418 atomic_set(&wq
->nr_cwqs_to_flush
, 1);
2421 for_each_cwq_cpu(cpu
, wq
) {
2422 struct cpu_workqueue_struct
*cwq
= get_cwq(cpu
, wq
);
2423 struct global_cwq
*gcwq
= cwq
->pool
->gcwq
;
2425 spin_lock_irq(&gcwq
->lock
);
2427 if (flush_color
>= 0) {
2428 BUG_ON(cwq
->flush_color
!= -1);
2430 if (cwq
->nr_in_flight
[flush_color
]) {
2431 cwq
->flush_color
= flush_color
;
2432 atomic_inc(&wq
->nr_cwqs_to_flush
);
2437 if (work_color
>= 0) {
2438 BUG_ON(work_color
!= work_next_color(cwq
->work_color
));
2439 cwq
->work_color
= work_color
;
2442 spin_unlock_irq(&gcwq
->lock
);
2445 if (flush_color
>= 0 && atomic_dec_and_test(&wq
->nr_cwqs_to_flush
))
2446 complete(&wq
->first_flusher
->done
);
2452 * flush_workqueue - ensure that any scheduled work has run to completion.
2453 * @wq: workqueue to flush
2455 * Forces execution of the workqueue and blocks until its completion.
2456 * This is typically used in driver shutdown handlers.
2458 * We sleep until all works which were queued on entry have been handled,
2459 * but we are not livelocked by new incoming ones.
2461 void flush_workqueue(struct workqueue_struct
*wq
)
2463 struct wq_flusher this_flusher
= {
2464 .list
= LIST_HEAD_INIT(this_flusher
.list
),
2466 .done
= COMPLETION_INITIALIZER_ONSTACK(this_flusher
.done
),
2470 lock_map_acquire(&wq
->lockdep_map
);
2471 lock_map_release(&wq
->lockdep_map
);
2473 mutex_lock(&wq
->flush_mutex
);
2476 * Start-to-wait phase
2478 next_color
= work_next_color(wq
->work_color
);
2480 if (next_color
!= wq
->flush_color
) {
2482 * Color space is not full. The current work_color
2483 * becomes our flush_color and work_color is advanced
2486 BUG_ON(!list_empty(&wq
->flusher_overflow
));
2487 this_flusher
.flush_color
= wq
->work_color
;
2488 wq
->work_color
= next_color
;
2490 if (!wq
->first_flusher
) {
2491 /* no flush in progress, become the first flusher */
2492 BUG_ON(wq
->flush_color
!= this_flusher
.flush_color
);
2494 wq
->first_flusher
= &this_flusher
;
2496 if (!flush_workqueue_prep_cwqs(wq
, wq
->flush_color
,
2498 /* nothing to flush, done */
2499 wq
->flush_color
= next_color
;
2500 wq
->first_flusher
= NULL
;
2505 BUG_ON(wq
->flush_color
== this_flusher
.flush_color
);
2506 list_add_tail(&this_flusher
.list
, &wq
->flusher_queue
);
2507 flush_workqueue_prep_cwqs(wq
, -1, wq
->work_color
);
2511 * Oops, color space is full, wait on overflow queue.
2512 * The next flush completion will assign us
2513 * flush_color and transfer to flusher_queue.
2515 list_add_tail(&this_flusher
.list
, &wq
->flusher_overflow
);
2518 mutex_unlock(&wq
->flush_mutex
);
2520 wait_for_completion(&this_flusher
.done
);
2523 * Wake-up-and-cascade phase
2525 * First flushers are responsible for cascading flushes and
2526 * handling overflow. Non-first flushers can simply return.
2528 if (wq
->first_flusher
!= &this_flusher
)
2531 mutex_lock(&wq
->flush_mutex
);
2533 /* we might have raced, check again with mutex held */
2534 if (wq
->first_flusher
!= &this_flusher
)
2537 wq
->first_flusher
= NULL
;
2539 BUG_ON(!list_empty(&this_flusher
.list
));
2540 BUG_ON(wq
->flush_color
!= this_flusher
.flush_color
);
2543 struct wq_flusher
*next
, *tmp
;
2545 /* complete all the flushers sharing the current flush color */
2546 list_for_each_entry_safe(next
, tmp
, &wq
->flusher_queue
, list
) {
2547 if (next
->flush_color
!= wq
->flush_color
)
2549 list_del_init(&next
->list
);
2550 complete(&next
->done
);
2553 BUG_ON(!list_empty(&wq
->flusher_overflow
) &&
2554 wq
->flush_color
!= work_next_color(wq
->work_color
));
2556 /* this flush_color is finished, advance by one */
2557 wq
->flush_color
= work_next_color(wq
->flush_color
);
2559 /* one color has been freed, handle overflow queue */
2560 if (!list_empty(&wq
->flusher_overflow
)) {
2562 * Assign the same color to all overflowed
2563 * flushers, advance work_color and append to
2564 * flusher_queue. This is the start-to-wait
2565 * phase for these overflowed flushers.
2567 list_for_each_entry(tmp
, &wq
->flusher_overflow
, list
)
2568 tmp
->flush_color
= wq
->work_color
;
2570 wq
->work_color
= work_next_color(wq
->work_color
);
2572 list_splice_tail_init(&wq
->flusher_overflow
,
2573 &wq
->flusher_queue
);
2574 flush_workqueue_prep_cwqs(wq
, -1, wq
->work_color
);
2577 if (list_empty(&wq
->flusher_queue
)) {
2578 BUG_ON(wq
->flush_color
!= wq
->work_color
);
2583 * Need to flush more colors. Make the next flusher
2584 * the new first flusher and arm cwqs.
2586 BUG_ON(wq
->flush_color
== wq
->work_color
);
2587 BUG_ON(wq
->flush_color
!= next
->flush_color
);
2589 list_del_init(&next
->list
);
2590 wq
->first_flusher
= next
;
2592 if (flush_workqueue_prep_cwqs(wq
, wq
->flush_color
, -1))
2596 * Meh... this color is already done, clear first
2597 * flusher and repeat cascading.
2599 wq
->first_flusher
= NULL
;
2603 mutex_unlock(&wq
->flush_mutex
);
2605 EXPORT_SYMBOL_GPL(flush_workqueue
);
2608 * drain_workqueue - drain a workqueue
2609 * @wq: workqueue to drain
2611 * Wait until the workqueue becomes empty. While draining is in progress,
2612 * only chain queueing is allowed. IOW, only currently pending or running
2613 * work items on @wq can queue further work items on it. @wq is flushed
2614 * repeatedly until it becomes empty. The number of flushing is detemined
2615 * by the depth of chaining and should be relatively short. Whine if it
2618 void drain_workqueue(struct workqueue_struct
*wq
)
2620 unsigned int flush_cnt
= 0;
2624 * __queue_work() needs to test whether there are drainers, is much
2625 * hotter than drain_workqueue() and already looks at @wq->flags.
2626 * Use WQ_DRAINING so that queue doesn't have to check nr_drainers.
2628 spin_lock(&workqueue_lock
);
2629 if (!wq
->nr_drainers
++)
2630 wq
->flags
|= WQ_DRAINING
;
2631 spin_unlock(&workqueue_lock
);
2633 flush_workqueue(wq
);
2635 for_each_cwq_cpu(cpu
, wq
) {
2636 struct cpu_workqueue_struct
*cwq
= get_cwq(cpu
, wq
);
2639 spin_lock_irq(&cwq
->pool
->gcwq
->lock
);
2640 drained
= !cwq
->nr_active
&& list_empty(&cwq
->delayed_works
);
2641 spin_unlock_irq(&cwq
->pool
->gcwq
->lock
);
2646 if (++flush_cnt
== 10 ||
2647 (flush_cnt
% 100 == 0 && flush_cnt
<= 1000))
2648 pr_warning("workqueue %s: flush on destruction isn't complete after %u tries\n",
2649 wq
->name
, flush_cnt
);
2653 spin_lock(&workqueue_lock
);
2654 if (!--wq
->nr_drainers
)
2655 wq
->flags
&= ~WQ_DRAINING
;
2656 spin_unlock(&workqueue_lock
);
2658 EXPORT_SYMBOL_GPL(drain_workqueue
);
2660 static bool start_flush_work(struct work_struct
*work
, struct wq_barrier
*barr
,
2661 bool wait_executing
)
2663 struct worker
*worker
= NULL
;
2664 struct global_cwq
*gcwq
;
2665 struct cpu_workqueue_struct
*cwq
;
2668 gcwq
= get_work_gcwq(work
);
2672 spin_lock_irq(&gcwq
->lock
);
2673 if (!list_empty(&work
->entry
)) {
2675 * See the comment near try_to_grab_pending()->smp_rmb().
2676 * If it was re-queued to a different gcwq under us, we
2677 * are not going to wait.
2680 cwq
= get_work_cwq(work
);
2681 if (unlikely(!cwq
|| gcwq
!= cwq
->pool
->gcwq
))
2683 } else if (wait_executing
) {
2684 worker
= find_worker_executing_work(gcwq
, work
);
2687 cwq
= worker
->current_cwq
;
2691 insert_wq_barrier(cwq
, barr
, work
, worker
);
2692 spin_unlock_irq(&gcwq
->lock
);
2695 * If @max_active is 1 or rescuer is in use, flushing another work
2696 * item on the same workqueue may lead to deadlock. Make sure the
2697 * flusher is not running on the same workqueue by verifying write
2700 if (cwq
->wq
->saved_max_active
== 1 || cwq
->wq
->flags
& WQ_RESCUER
)
2701 lock_map_acquire(&cwq
->wq
->lockdep_map
);
2703 lock_map_acquire_read(&cwq
->wq
->lockdep_map
);
2704 lock_map_release(&cwq
->wq
->lockdep_map
);
2708 spin_unlock_irq(&gcwq
->lock
);
2713 * flush_work - wait for a work to finish executing the last queueing instance
2714 * @work: the work to flush
2716 * Wait until @work has finished execution. This function considers
2717 * only the last queueing instance of @work. If @work has been
2718 * enqueued across different CPUs on a non-reentrant workqueue or on
2719 * multiple workqueues, @work might still be executing on return on
2720 * some of the CPUs from earlier queueing.
2722 * If @work was queued only on a non-reentrant, ordered or unbound
2723 * workqueue, @work is guaranteed to be idle on return if it hasn't
2724 * been requeued since flush started.
2727 * %true if flush_work() waited for the work to finish execution,
2728 * %false if it was already idle.
2730 bool flush_work(struct work_struct
*work
)
2732 struct wq_barrier barr
;
2734 lock_map_acquire(&work
->lockdep_map
);
2735 lock_map_release(&work
->lockdep_map
);
2737 if (start_flush_work(work
, &barr
, true)) {
2738 wait_for_completion(&barr
.done
);
2739 destroy_work_on_stack(&barr
.work
);
2744 EXPORT_SYMBOL_GPL(flush_work
);
2746 static bool wait_on_cpu_work(struct global_cwq
*gcwq
, struct work_struct
*work
)
2748 struct wq_barrier barr
;
2749 struct worker
*worker
;
2751 spin_lock_irq(&gcwq
->lock
);
2753 worker
= find_worker_executing_work(gcwq
, work
);
2754 if (unlikely(worker
))
2755 insert_wq_barrier(worker
->current_cwq
, &barr
, work
, worker
);
2757 spin_unlock_irq(&gcwq
->lock
);
2759 if (unlikely(worker
)) {
2760 wait_for_completion(&barr
.done
);
2761 destroy_work_on_stack(&barr
.work
);
2767 static bool wait_on_work(struct work_struct
*work
)
2774 lock_map_acquire(&work
->lockdep_map
);
2775 lock_map_release(&work
->lockdep_map
);
2777 for_each_gcwq_cpu(cpu
)
2778 ret
|= wait_on_cpu_work(get_gcwq(cpu
), work
);
2783 * flush_work_sync - wait until a work has finished execution
2784 * @work: the work to flush
2786 * Wait until @work has finished execution. On return, it's
2787 * guaranteed that all queueing instances of @work which happened
2788 * before this function is called are finished. In other words, if
2789 * @work hasn't been requeued since this function was called, @work is
2790 * guaranteed to be idle on return.
2793 * %true if flush_work_sync() waited for the work to finish execution,
2794 * %false if it was already idle.
2796 bool flush_work_sync(struct work_struct
*work
)
2798 struct wq_barrier barr
;
2799 bool pending
, waited
;
2801 /* we'll wait for executions separately, queue barr only if pending */
2802 pending
= start_flush_work(work
, &barr
, false);
2804 /* wait for executions to finish */
2805 waited
= wait_on_work(work
);
2807 /* wait for the pending one */
2809 wait_for_completion(&barr
.done
);
2810 destroy_work_on_stack(&barr
.work
);
2813 return pending
|| waited
;
2815 EXPORT_SYMBOL_GPL(flush_work_sync
);
2818 * Upon a successful return (>= 0), the caller "owns" WORK_STRUCT_PENDING bit,
2819 * so this work can't be re-armed in any way.
2821 static int try_to_grab_pending(struct work_struct
*work
)
2823 struct global_cwq
*gcwq
;
2826 if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT
, work_data_bits(work
)))
2830 * The queueing is in progress, or it is already queued. Try to
2831 * steal it from ->worklist without clearing WORK_STRUCT_PENDING.
2833 gcwq
= get_work_gcwq(work
);
2837 spin_lock_irq(&gcwq
->lock
);
2838 if (!list_empty(&work
->entry
)) {
2840 * This work is queued, but perhaps we locked the wrong gcwq.
2841 * In that case we must see the new value after rmb(), see
2842 * insert_work()->wmb().
2845 if (gcwq
== get_work_gcwq(work
)) {
2846 debug_work_deactivate(work
);
2847 list_del_init(&work
->entry
);
2848 cwq_dec_nr_in_flight(get_work_cwq(work
),
2849 get_work_color(work
),
2850 *work_data_bits(work
) & WORK_STRUCT_DELAYED
);
2854 spin_unlock_irq(&gcwq
->lock
);
2859 static bool __cancel_work_timer(struct work_struct
*work
,
2860 struct timer_list
* timer
)
2865 ret
= (timer
&& likely(del_timer(timer
)));
2867 ret
= try_to_grab_pending(work
);
2869 } while (unlikely(ret
< 0));
2871 clear_work_data(work
);
2876 * cancel_work_sync - cancel a work and wait for it to finish
2877 * @work: the work to cancel
2879 * Cancel @work and wait for its execution to finish. This function
2880 * can be used even if the work re-queues itself or migrates to
2881 * another workqueue. On return from this function, @work is
2882 * guaranteed to be not pending or executing on any CPU.
2884 * cancel_work_sync(&delayed_work->work) must not be used for
2885 * delayed_work's. Use cancel_delayed_work_sync() instead.
2887 * The caller must ensure that the workqueue on which @work was last
2888 * queued can't be destroyed before this function returns.
2891 * %true if @work was pending, %false otherwise.
2893 bool cancel_work_sync(struct work_struct
*work
)
2895 return __cancel_work_timer(work
, NULL
);
2897 EXPORT_SYMBOL_GPL(cancel_work_sync
);
2900 * flush_delayed_work - wait for a dwork to finish executing the last queueing
2901 * @dwork: the delayed work to flush
2903 * Delayed timer is cancelled and the pending work is queued for
2904 * immediate execution. Like flush_work(), this function only
2905 * considers the last queueing instance of @dwork.
2908 * %true if flush_work() waited for the work to finish execution,
2909 * %false if it was already idle.
2911 bool flush_delayed_work(struct delayed_work
*dwork
)
2913 if (del_timer_sync(&dwork
->timer
))
2914 __queue_work(raw_smp_processor_id(),
2915 get_work_cwq(&dwork
->work
)->wq
, &dwork
->work
);
2916 return flush_work(&dwork
->work
);
2918 EXPORT_SYMBOL(flush_delayed_work
);
2921 * flush_delayed_work_sync - wait for a dwork to finish
2922 * @dwork: the delayed work to flush
2924 * Delayed timer is cancelled and the pending work is queued for
2925 * execution immediately. Other than timer handling, its behavior
2926 * is identical to flush_work_sync().
2929 * %true if flush_work_sync() waited for the work to finish execution,
2930 * %false if it was already idle.
2932 bool flush_delayed_work_sync(struct delayed_work
*dwork
)
2934 if (del_timer_sync(&dwork
->timer
))
2935 __queue_work(raw_smp_processor_id(),
2936 get_work_cwq(&dwork
->work
)->wq
, &dwork
->work
);
2937 return flush_work_sync(&dwork
->work
);
2939 EXPORT_SYMBOL(flush_delayed_work_sync
);
2942 * cancel_delayed_work_sync - cancel a delayed work and wait for it to finish
2943 * @dwork: the delayed work cancel
2945 * This is cancel_work_sync() for delayed works.
2948 * %true if @dwork was pending, %false otherwise.
2950 bool cancel_delayed_work_sync(struct delayed_work
*dwork
)
2952 return __cancel_work_timer(&dwork
->work
, &dwork
->timer
);
2954 EXPORT_SYMBOL(cancel_delayed_work_sync
);
2957 * schedule_work - put work task in global workqueue
2958 * @work: job to be done
2960 * Returns zero if @work was already on the kernel-global workqueue and
2961 * non-zero otherwise.
2963 * This puts a job in the kernel-global workqueue if it was not already
2964 * queued and leaves it in the same position on the kernel-global
2965 * workqueue otherwise.
2967 int schedule_work(struct work_struct
*work
)
2969 return queue_work(system_wq
, work
);
2971 EXPORT_SYMBOL(schedule_work
);
2974 * schedule_work_on - put work task on a specific cpu
2975 * @cpu: cpu to put the work task on
2976 * @work: job to be done
2978 * This puts a job on a specific cpu
2980 int schedule_work_on(int cpu
, struct work_struct
*work
)
2982 return queue_work_on(cpu
, system_wq
, work
);
2984 EXPORT_SYMBOL(schedule_work_on
);
2987 * schedule_delayed_work - put work task in global workqueue after delay
2988 * @dwork: job to be done
2989 * @delay: number of jiffies to wait or 0 for immediate execution
2991 * After waiting for a given time this puts a job in the kernel-global
2994 int schedule_delayed_work(struct delayed_work
*dwork
,
2995 unsigned long delay
)
2997 return queue_delayed_work(system_wq
, dwork
, delay
);
2999 EXPORT_SYMBOL(schedule_delayed_work
);
3002 * schedule_delayed_work_on - queue work in global workqueue on CPU after delay
3004 * @dwork: job to be done
3005 * @delay: number of jiffies to wait
3007 * After waiting for a given time this puts a job in the kernel-global
3008 * workqueue on the specified CPU.
3010 int schedule_delayed_work_on(int cpu
,
3011 struct delayed_work
*dwork
, unsigned long delay
)
3013 return queue_delayed_work_on(cpu
, system_wq
, dwork
, delay
);
3015 EXPORT_SYMBOL(schedule_delayed_work_on
);
3018 * schedule_on_each_cpu - execute a function synchronously on each online CPU
3019 * @func: the function to call
3021 * schedule_on_each_cpu() executes @func on each online CPU using the
3022 * system workqueue and blocks until all CPUs have completed.
3023 * schedule_on_each_cpu() is very slow.
3026 * 0 on success, -errno on failure.
3028 int schedule_on_each_cpu(work_func_t func
)
3031 struct work_struct __percpu
*works
;
3033 works
= alloc_percpu(struct work_struct
);
3039 for_each_online_cpu(cpu
) {
3040 struct work_struct
*work
= per_cpu_ptr(works
, cpu
);
3042 INIT_WORK(work
, func
);
3043 schedule_work_on(cpu
, work
);
3046 for_each_online_cpu(cpu
)
3047 flush_work(per_cpu_ptr(works
, cpu
));
3055 * flush_scheduled_work - ensure that any scheduled work has run to completion.
3057 * Forces execution of the kernel-global workqueue and blocks until its
3060 * Think twice before calling this function! It's very easy to get into
3061 * trouble if you don't take great care. Either of the following situations
3062 * will lead to deadlock:
3064 * One of the work items currently on the workqueue needs to acquire
3065 * a lock held by your code or its caller.
3067 * Your code is running in the context of a work routine.
3069 * They will be detected by lockdep when they occur, but the first might not
3070 * occur very often. It depends on what work items are on the workqueue and
3071 * what locks they need, which you have no control over.
3073 * In most situations flushing the entire workqueue is overkill; you merely
3074 * need to know that a particular work item isn't queued and isn't running.
3075 * In such cases you should use cancel_delayed_work_sync() or
3076 * cancel_work_sync() instead.
3078 void flush_scheduled_work(void)
3080 flush_workqueue(system_wq
);
3082 EXPORT_SYMBOL(flush_scheduled_work
);
3085 * execute_in_process_context - reliably execute the routine with user context
3086 * @fn: the function to execute
3087 * @ew: guaranteed storage for the execute work structure (must
3088 * be available when the work executes)
3090 * Executes the function immediately if process context is available,
3091 * otherwise schedules the function for delayed execution.
3093 * Returns: 0 - function was executed
3094 * 1 - function was scheduled for execution
3096 int execute_in_process_context(work_func_t fn
, struct execute_work
*ew
)
3098 if (!in_interrupt()) {
3103 INIT_WORK(&ew
->work
, fn
);
3104 schedule_work(&ew
->work
);
3108 EXPORT_SYMBOL_GPL(execute_in_process_context
);
3110 int keventd_up(void)
3112 return system_wq
!= NULL
;
3115 static int alloc_cwqs(struct workqueue_struct
*wq
)
3118 * cwqs are forced aligned according to WORK_STRUCT_FLAG_BITS.
3119 * Make sure that the alignment isn't lower than that of
3120 * unsigned long long.
3122 const size_t size
= sizeof(struct cpu_workqueue_struct
);
3123 const size_t align
= max_t(size_t, 1 << WORK_STRUCT_FLAG_BITS
,
3124 __alignof__(unsigned long long));
3126 if (!(wq
->flags
& WQ_UNBOUND
))
3127 wq
->cpu_wq
.pcpu
= __alloc_percpu(size
, align
);
3132 * Allocate enough room to align cwq and put an extra
3133 * pointer at the end pointing back to the originally
3134 * allocated pointer which will be used for free.
3136 ptr
= kzalloc(size
+ align
+ sizeof(void *), GFP_KERNEL
);
3138 wq
->cpu_wq
.single
= PTR_ALIGN(ptr
, align
);
3139 *(void **)(wq
->cpu_wq
.single
+ 1) = ptr
;
3143 /* just in case, make sure it's actually aligned */
3144 BUG_ON(!IS_ALIGNED(wq
->cpu_wq
.v
, align
));
3145 return wq
->cpu_wq
.v
? 0 : -ENOMEM
;
3148 static void free_cwqs(struct workqueue_struct
*wq
)
3150 if (!(wq
->flags
& WQ_UNBOUND
))
3151 free_percpu(wq
->cpu_wq
.pcpu
);
3152 else if (wq
->cpu_wq
.single
) {
3153 /* the pointer to free is stored right after the cwq */
3154 kfree(*(void **)(wq
->cpu_wq
.single
+ 1));
3158 static int wq_clamp_max_active(int max_active
, unsigned int flags
,
3161 int lim
= flags
& WQ_UNBOUND
? WQ_UNBOUND_MAX_ACTIVE
: WQ_MAX_ACTIVE
;
3163 if (max_active
< 1 || max_active
> lim
)
3164 printk(KERN_WARNING
"workqueue: max_active %d requested for %s "
3165 "is out of range, clamping between %d and %d\n",
3166 max_active
, name
, 1, lim
);
3168 return clamp_val(max_active
, 1, lim
);
3171 struct workqueue_struct
*__alloc_workqueue_key(const char *fmt
,
3174 struct lock_class_key
*key
,
3175 const char *lock_name
, ...)
3177 va_list args
, args1
;
3178 struct workqueue_struct
*wq
;
3182 /* determine namelen, allocate wq and format name */
3183 va_start(args
, lock_name
);
3184 va_copy(args1
, args
);
3185 namelen
= vsnprintf(NULL
, 0, fmt
, args
) + 1;
3187 wq
= kzalloc(sizeof(*wq
) + namelen
, GFP_KERNEL
);
3191 vsnprintf(wq
->name
, namelen
, fmt
, args1
);
3196 * Workqueues which may be used during memory reclaim should
3197 * have a rescuer to guarantee forward progress.
3199 if (flags
& WQ_MEM_RECLAIM
)
3200 flags
|= WQ_RESCUER
;
3202 max_active
= max_active
?: WQ_DFL_ACTIVE
;
3203 max_active
= wq_clamp_max_active(max_active
, flags
, wq
->name
);
3207 wq
->saved_max_active
= max_active
;
3208 mutex_init(&wq
->flush_mutex
);
3209 atomic_set(&wq
->nr_cwqs_to_flush
, 0);
3210 INIT_LIST_HEAD(&wq
->flusher_queue
);
3211 INIT_LIST_HEAD(&wq
->flusher_overflow
);
3213 lockdep_init_map(&wq
->lockdep_map
, lock_name
, key
, 0);
3214 INIT_LIST_HEAD(&wq
->list
);
3216 if (alloc_cwqs(wq
) < 0)
3219 for_each_cwq_cpu(cpu
, wq
) {
3220 struct cpu_workqueue_struct
*cwq
= get_cwq(cpu
, wq
);
3221 struct global_cwq
*gcwq
= get_gcwq(cpu
);
3222 int pool_idx
= (bool)(flags
& WQ_HIGHPRI
);
3224 BUG_ON((unsigned long)cwq
& WORK_STRUCT_FLAG_MASK
);
3225 cwq
->pool
= &gcwq
->pools
[pool_idx
];
3227 cwq
->flush_color
= -1;
3228 cwq
->max_active
= max_active
;
3229 INIT_LIST_HEAD(&cwq
->delayed_works
);
3232 if (flags
& WQ_RESCUER
) {
3233 struct worker
*rescuer
;
3235 if (!alloc_mayday_mask(&wq
->mayday_mask
, GFP_KERNEL
))
3238 wq
->rescuer
= rescuer
= alloc_worker();
3242 rescuer
->task
= kthread_create(rescuer_thread
, wq
, "%s",
3244 if (IS_ERR(rescuer
->task
))
3247 rescuer
->task
->flags
|= PF_THREAD_BOUND
;
3248 wake_up_process(rescuer
->task
);
3252 * workqueue_lock protects global freeze state and workqueues
3253 * list. Grab it, set max_active accordingly and add the new
3254 * workqueue to workqueues list.
3256 spin_lock(&workqueue_lock
);
3258 if (workqueue_freezing
&& wq
->flags
& WQ_FREEZABLE
)
3259 for_each_cwq_cpu(cpu
, wq
)
3260 get_cwq(cpu
, wq
)->max_active
= 0;
3262 list_add(&wq
->list
, &workqueues
);
3264 spin_unlock(&workqueue_lock
);
3270 free_mayday_mask(wq
->mayday_mask
);
3276 EXPORT_SYMBOL_GPL(__alloc_workqueue_key
);
3279 * destroy_workqueue - safely terminate a workqueue
3280 * @wq: target workqueue
3282 * Safely destroy a workqueue. All work currently pending will be done first.
3284 void destroy_workqueue(struct workqueue_struct
*wq
)
3288 /* drain it before proceeding with destruction */
3289 drain_workqueue(wq
);
3292 * wq list is used to freeze wq, remove from list after
3293 * flushing is complete in case freeze races us.
3295 spin_lock(&workqueue_lock
);
3296 list_del(&wq
->list
);
3297 spin_unlock(&workqueue_lock
);
3300 for_each_cwq_cpu(cpu
, wq
) {
3301 struct cpu_workqueue_struct
*cwq
= get_cwq(cpu
, wq
);
3304 for (i
= 0; i
< WORK_NR_COLORS
; i
++)
3305 BUG_ON(cwq
->nr_in_flight
[i
]);
3306 BUG_ON(cwq
->nr_active
);
3307 BUG_ON(!list_empty(&cwq
->delayed_works
));
3310 if (wq
->flags
& WQ_RESCUER
) {
3311 kthread_stop(wq
->rescuer
->task
);
3312 free_mayday_mask(wq
->mayday_mask
);
3319 EXPORT_SYMBOL_GPL(destroy_workqueue
);
3322 * workqueue_set_max_active - adjust max_active of a workqueue
3323 * @wq: target workqueue
3324 * @max_active: new max_active value.
3326 * Set max_active of @wq to @max_active.
3329 * Don't call from IRQ context.
3331 void workqueue_set_max_active(struct workqueue_struct
*wq
, int max_active
)
3335 max_active
= wq_clamp_max_active(max_active
, wq
->flags
, wq
->name
);
3337 spin_lock(&workqueue_lock
);
3339 wq
->saved_max_active
= max_active
;
3341 for_each_cwq_cpu(cpu
, wq
) {
3342 struct global_cwq
*gcwq
= get_gcwq(cpu
);
3344 spin_lock_irq(&gcwq
->lock
);
3346 if (!(wq
->flags
& WQ_FREEZABLE
) ||
3347 !(gcwq
->flags
& GCWQ_FREEZING
))
3348 get_cwq(gcwq
->cpu
, wq
)->max_active
= max_active
;
3350 spin_unlock_irq(&gcwq
->lock
);
3353 spin_unlock(&workqueue_lock
);
3355 EXPORT_SYMBOL_GPL(workqueue_set_max_active
);
3358 * workqueue_congested - test whether a workqueue is congested
3359 * @cpu: CPU in question
3360 * @wq: target workqueue
3362 * Test whether @wq's cpu workqueue for @cpu is congested. There is
3363 * no synchronization around this function and the test result is
3364 * unreliable and only useful as advisory hints or for debugging.
3367 * %true if congested, %false otherwise.
3369 bool workqueue_congested(unsigned int cpu
, struct workqueue_struct
*wq
)
3371 struct cpu_workqueue_struct
*cwq
= get_cwq(cpu
, wq
);
3373 return !list_empty(&cwq
->delayed_works
);
3375 EXPORT_SYMBOL_GPL(workqueue_congested
);
3378 * work_cpu - return the last known associated cpu for @work
3379 * @work: the work of interest
3382 * CPU number if @work was ever queued. WORK_CPU_NONE otherwise.
3384 unsigned int work_cpu(struct work_struct
*work
)
3386 struct global_cwq
*gcwq
= get_work_gcwq(work
);
3388 return gcwq
? gcwq
->cpu
: WORK_CPU_NONE
;
3390 EXPORT_SYMBOL_GPL(work_cpu
);
3393 * work_busy - test whether a work is currently pending or running
3394 * @work: the work to be tested
3396 * Test whether @work is currently pending or running. There is no
3397 * synchronization around this function and the test result is
3398 * unreliable and only useful as advisory hints or for debugging.
3399 * Especially for reentrant wqs, the pending state might hide the
3403 * OR'd bitmask of WORK_BUSY_* bits.
3405 unsigned int work_busy(struct work_struct
*work
)
3407 struct global_cwq
*gcwq
= get_work_gcwq(work
);
3408 unsigned long flags
;
3409 unsigned int ret
= 0;
3414 spin_lock_irqsave(&gcwq
->lock
, flags
);
3416 if (work_pending(work
))
3417 ret
|= WORK_BUSY_PENDING
;
3418 if (find_worker_executing_work(gcwq
, work
))
3419 ret
|= WORK_BUSY_RUNNING
;
3421 spin_unlock_irqrestore(&gcwq
->lock
, flags
);
3425 EXPORT_SYMBOL_GPL(work_busy
);
3430 * There are two challenges in supporting CPU hotplug. Firstly, there
3431 * are a lot of assumptions on strong associations among work, cwq and
3432 * gcwq which make migrating pending and scheduled works very
3433 * difficult to implement without impacting hot paths. Secondly,
3434 * gcwqs serve mix of short, long and very long running works making
3435 * blocked draining impractical.
3437 * This is solved by allowing a gcwq to be disassociated from the CPU
3438 * running as an unbound one and allowing it to be reattached later if the
3439 * cpu comes back online.
3442 /* claim manager positions of all pools */
3443 static void gcwq_claim_management_and_lock(struct global_cwq
*gcwq
)
3445 struct worker_pool
*pool
;
3447 for_each_worker_pool(pool
, gcwq
)
3448 mutex_lock_nested(&pool
->manager_mutex
, pool
- gcwq
->pools
);
3449 spin_lock_irq(&gcwq
->lock
);
3452 /* release manager positions */
3453 static void gcwq_release_management_and_unlock(struct global_cwq
*gcwq
)
3455 struct worker_pool
*pool
;
3457 spin_unlock_irq(&gcwq
->lock
);
3458 for_each_worker_pool(pool
, gcwq
)
3459 mutex_unlock(&pool
->manager_mutex
);
3462 static void gcwq_unbind_fn(struct work_struct
*work
)
3464 struct global_cwq
*gcwq
= get_gcwq(smp_processor_id());
3465 struct worker_pool
*pool
;
3466 struct worker
*worker
;
3467 struct hlist_node
*pos
;
3470 BUG_ON(gcwq
->cpu
!= smp_processor_id());
3472 gcwq_claim_management_and_lock(gcwq
);
3475 * We've claimed all manager positions. Make all workers unbound
3476 * and set DISASSOCIATED. Before this, all workers except for the
3477 * ones which are still executing works from before the last CPU
3478 * down must be on the cpu. After this, they may become diasporas.
3480 for_each_worker_pool(pool
, gcwq
)
3481 list_for_each_entry(worker
, &pool
->idle_list
, entry
)
3482 worker
->flags
|= WORKER_UNBOUND
;
3484 for_each_busy_worker(worker
, i
, pos
, gcwq
)
3485 worker
->flags
|= WORKER_UNBOUND
;
3487 gcwq
->flags
|= GCWQ_DISASSOCIATED
;
3489 gcwq_release_management_and_unlock(gcwq
);
3492 * Call schedule() so that we cross rq->lock and thus can guarantee
3493 * sched callbacks see the %WORKER_UNBOUND flag. This is necessary
3494 * as scheduler callbacks may be invoked from other cpus.
3499 * Sched callbacks are disabled now. Zap nr_running. After this,
3500 * nr_running stays zero and need_more_worker() and keep_working()
3501 * are always true as long as the worklist is not empty. @gcwq now
3502 * behaves as unbound (in terms of concurrency management) gcwq
3503 * which is served by workers tied to the CPU.
3505 * On return from this function, the current worker would trigger
3506 * unbound chain execution of pending work items if other workers
3509 for_each_worker_pool(pool
, gcwq
)
3510 atomic_set(get_pool_nr_running(pool
), 0);
3514 * Workqueues should be brought up before normal priority CPU notifiers.
3515 * This will be registered high priority CPU notifier.
3517 static int __devinit
workqueue_cpu_up_callback(struct notifier_block
*nfb
,
3518 unsigned long action
,
3521 unsigned int cpu
= (unsigned long)hcpu
;
3522 struct global_cwq
*gcwq
= get_gcwq(cpu
);
3523 struct worker_pool
*pool
;
3525 switch (action
& ~CPU_TASKS_FROZEN
) {
3526 case CPU_UP_PREPARE
:
3527 for_each_worker_pool(pool
, gcwq
) {
3528 struct worker
*worker
;
3530 if (pool
->nr_workers
)
3533 worker
= create_worker(pool
);
3537 spin_lock_irq(&gcwq
->lock
);
3538 start_worker(worker
);
3539 spin_unlock_irq(&gcwq
->lock
);
3543 case CPU_DOWN_FAILED
:
3545 gcwq_claim_management_and_lock(gcwq
);
3546 gcwq
->flags
&= ~GCWQ_DISASSOCIATED
;
3547 rebind_workers(gcwq
);
3548 gcwq_release_management_and_unlock(gcwq
);
3555 * Workqueues should be brought down after normal priority CPU notifiers.
3556 * This will be registered as low priority CPU notifier.
3558 static int __devinit
workqueue_cpu_down_callback(struct notifier_block
*nfb
,
3559 unsigned long action
,
3562 unsigned int cpu
= (unsigned long)hcpu
;
3563 struct work_struct unbind_work
;
3565 switch (action
& ~CPU_TASKS_FROZEN
) {
3566 case CPU_DOWN_PREPARE
:
3567 /* unbinding should happen on the local CPU */
3568 INIT_WORK_ONSTACK(&unbind_work
, gcwq_unbind_fn
);
3569 schedule_work_on(cpu
, &unbind_work
);
3570 flush_work(&unbind_work
);
3578 struct work_for_cpu
{
3579 struct work_struct work
;
3585 static void work_for_cpu_fn(struct work_struct
*work
)
3587 struct work_for_cpu
*wfc
= container_of(work
, struct work_for_cpu
, work
);
3589 wfc
->ret
= wfc
->fn(wfc
->arg
);
3593 * work_on_cpu - run a function in user context on a particular cpu
3594 * @cpu: the cpu to run on
3595 * @fn: the function to run
3596 * @arg: the function arg
3598 * This will return the value @fn returns.
3599 * It is up to the caller to ensure that the cpu doesn't go offline.
3600 * The caller must not hold any locks which would prevent @fn from completing.
3602 long work_on_cpu(unsigned int cpu
, long (*fn
)(void *), void *arg
)
3604 struct work_for_cpu wfc
= { .fn
= fn
, .arg
= arg
};
3606 INIT_WORK_ONSTACK(&wfc
.work
, work_for_cpu_fn
);
3607 schedule_work_on(cpu
, &wfc
.work
);
3608 flush_work(&wfc
.work
);
3611 EXPORT_SYMBOL_GPL(work_on_cpu
);
3612 #endif /* CONFIG_SMP */
3614 #ifdef CONFIG_FREEZER
3617 * freeze_workqueues_begin - begin freezing workqueues
3619 * Start freezing workqueues. After this function returns, all freezable
3620 * workqueues will queue new works to their frozen_works list instead of
3624 * Grabs and releases workqueue_lock and gcwq->lock's.
3626 void freeze_workqueues_begin(void)
3630 spin_lock(&workqueue_lock
);
3632 BUG_ON(workqueue_freezing
);
3633 workqueue_freezing
= true;
3635 for_each_gcwq_cpu(cpu
) {
3636 struct global_cwq
*gcwq
= get_gcwq(cpu
);
3637 struct workqueue_struct
*wq
;
3639 spin_lock_irq(&gcwq
->lock
);
3641 BUG_ON(gcwq
->flags
& GCWQ_FREEZING
);
3642 gcwq
->flags
|= GCWQ_FREEZING
;
3644 list_for_each_entry(wq
, &workqueues
, list
) {
3645 struct cpu_workqueue_struct
*cwq
= get_cwq(cpu
, wq
);
3647 if (cwq
&& wq
->flags
& WQ_FREEZABLE
)
3648 cwq
->max_active
= 0;
3651 spin_unlock_irq(&gcwq
->lock
);
3654 spin_unlock(&workqueue_lock
);
3658 * freeze_workqueues_busy - are freezable workqueues still busy?
3660 * Check whether freezing is complete. This function must be called
3661 * between freeze_workqueues_begin() and thaw_workqueues().
3664 * Grabs and releases workqueue_lock.
3667 * %true if some freezable workqueues are still busy. %false if freezing
3670 bool freeze_workqueues_busy(void)
3675 spin_lock(&workqueue_lock
);
3677 BUG_ON(!workqueue_freezing
);
3679 for_each_gcwq_cpu(cpu
) {
3680 struct workqueue_struct
*wq
;
3682 * nr_active is monotonically decreasing. It's safe
3683 * to peek without lock.
3685 list_for_each_entry(wq
, &workqueues
, list
) {
3686 struct cpu_workqueue_struct
*cwq
= get_cwq(cpu
, wq
);
3688 if (!cwq
|| !(wq
->flags
& WQ_FREEZABLE
))
3691 BUG_ON(cwq
->nr_active
< 0);
3692 if (cwq
->nr_active
) {
3699 spin_unlock(&workqueue_lock
);
3704 * thaw_workqueues - thaw workqueues
3706 * Thaw workqueues. Normal queueing is restored and all collected
3707 * frozen works are transferred to their respective gcwq worklists.
3710 * Grabs and releases workqueue_lock and gcwq->lock's.
3712 void thaw_workqueues(void)
3716 spin_lock(&workqueue_lock
);
3718 if (!workqueue_freezing
)
3721 for_each_gcwq_cpu(cpu
) {
3722 struct global_cwq
*gcwq
= get_gcwq(cpu
);
3723 struct worker_pool
*pool
;
3724 struct workqueue_struct
*wq
;
3726 spin_lock_irq(&gcwq
->lock
);
3728 BUG_ON(!(gcwq
->flags
& GCWQ_FREEZING
));
3729 gcwq
->flags
&= ~GCWQ_FREEZING
;
3731 list_for_each_entry(wq
, &workqueues
, list
) {
3732 struct cpu_workqueue_struct
*cwq
= get_cwq(cpu
, wq
);
3734 if (!cwq
|| !(wq
->flags
& WQ_FREEZABLE
))
3737 /* restore max_active and repopulate worklist */
3738 cwq
->max_active
= wq
->saved_max_active
;
3740 while (!list_empty(&cwq
->delayed_works
) &&
3741 cwq
->nr_active
< cwq
->max_active
)
3742 cwq_activate_first_delayed(cwq
);
3745 for_each_worker_pool(pool
, gcwq
)
3746 wake_up_worker(pool
);
3748 spin_unlock_irq(&gcwq
->lock
);
3751 workqueue_freezing
= false;
3753 spin_unlock(&workqueue_lock
);
3755 #endif /* CONFIG_FREEZER */
3757 static int __init
init_workqueues(void)
3762 cpu_notifier(workqueue_cpu_up_callback
, CPU_PRI_WORKQUEUE_UP
);
3763 cpu_notifier(workqueue_cpu_down_callback
, CPU_PRI_WORKQUEUE_DOWN
);
3765 /* initialize gcwqs */
3766 for_each_gcwq_cpu(cpu
) {
3767 struct global_cwq
*gcwq
= get_gcwq(cpu
);
3768 struct worker_pool
*pool
;
3770 spin_lock_init(&gcwq
->lock
);
3772 gcwq
->flags
|= GCWQ_DISASSOCIATED
;
3774 for (i
= 0; i
< BUSY_WORKER_HASH_SIZE
; i
++)
3775 INIT_HLIST_HEAD(&gcwq
->busy_hash
[i
]);
3777 for_each_worker_pool(pool
, gcwq
) {
3779 INIT_LIST_HEAD(&pool
->worklist
);
3780 INIT_LIST_HEAD(&pool
->idle_list
);
3782 init_timer_deferrable(&pool
->idle_timer
);
3783 pool
->idle_timer
.function
= idle_worker_timeout
;
3784 pool
->idle_timer
.data
= (unsigned long)pool
;
3786 setup_timer(&pool
->mayday_timer
, gcwq_mayday_timeout
,
3787 (unsigned long)pool
);
3789 mutex_init(&pool
->manager_mutex
);
3790 ida_init(&pool
->worker_ida
);
3793 init_waitqueue_head(&gcwq
->rebind_hold
);
3796 /* create the initial worker */
3797 for_each_online_gcwq_cpu(cpu
) {
3798 struct global_cwq
*gcwq
= get_gcwq(cpu
);
3799 struct worker_pool
*pool
;
3801 if (cpu
!= WORK_CPU_UNBOUND
)
3802 gcwq
->flags
&= ~GCWQ_DISASSOCIATED
;
3804 for_each_worker_pool(pool
, gcwq
) {
3805 struct worker
*worker
;
3807 worker
= create_worker(pool
);
3809 spin_lock_irq(&gcwq
->lock
);
3810 start_worker(worker
);
3811 spin_unlock_irq(&gcwq
->lock
);
3815 system_wq
= alloc_workqueue("events", 0, 0);
3816 system_long_wq
= alloc_workqueue("events_long", 0, 0);
3817 system_nrt_wq
= alloc_workqueue("events_nrt", WQ_NON_REENTRANT
, 0);
3818 system_unbound_wq
= alloc_workqueue("events_unbound", WQ_UNBOUND
,
3819 WQ_UNBOUND_MAX_ACTIVE
);
3820 system_freezable_wq
= alloc_workqueue("events_freezable",
3822 system_nrt_freezable_wq
= alloc_workqueue("events_nrt_freezable",
3823 WQ_NON_REENTRANT
| WQ_FREEZABLE
, 0);
3824 BUG_ON(!system_wq
|| !system_long_wq
|| !system_nrt_wq
||
3825 !system_unbound_wq
|| !system_freezable_wq
||
3826 !system_nrt_freezable_wq
);
3829 early_initcall(init_workqueues
);