2 * workqueue.h --- work queue handling for Linux.
5 #ifndef _LINUX_WORKQUEUE_H
6 #define _LINUX_WORKQUEUE_H
8 #include <linux/timer.h>
9 #include <linux/linkage.h>
10 #include <linux/bitops.h>
11 #include <linux/lockdep.h>
12 #include <linux/threads.h>
13 #include <linux/atomic.h>
14 #include <linux/cpumask.h>
16 struct workqueue_struct
;
19 typedef void (*work_func_t
)(struct work_struct
*work
);
20 void delayed_work_timer_fn(unsigned long __data
);
23 * The first word is the work queue pointer and the flags rolled into
26 #define work_data_bits(work) ((unsigned long *)(&(work)->data))
29 WORK_STRUCT_PENDING_BIT
= 0, /* work item is pending execution */
30 WORK_STRUCT_DELAYED_BIT
= 1, /* work item is delayed */
31 WORK_STRUCT_PWQ_BIT
= 2, /* data points to pwq */
32 WORK_STRUCT_LINKED_BIT
= 3, /* next work is linked to this one */
33 #ifdef CONFIG_DEBUG_OBJECTS_WORK
34 WORK_STRUCT_STATIC_BIT
= 4, /* static initializer (debugobjects) */
35 WORK_STRUCT_COLOR_SHIFT
= 5, /* color for workqueue flushing */
37 WORK_STRUCT_COLOR_SHIFT
= 4, /* color for workqueue flushing */
40 WORK_STRUCT_COLOR_BITS
= 4,
42 WORK_STRUCT_PENDING
= 1 << WORK_STRUCT_PENDING_BIT
,
43 WORK_STRUCT_DELAYED
= 1 << WORK_STRUCT_DELAYED_BIT
,
44 WORK_STRUCT_PWQ
= 1 << WORK_STRUCT_PWQ_BIT
,
45 WORK_STRUCT_LINKED
= 1 << WORK_STRUCT_LINKED_BIT
,
46 #ifdef CONFIG_DEBUG_OBJECTS_WORK
47 WORK_STRUCT_STATIC
= 1 << WORK_STRUCT_STATIC_BIT
,
49 WORK_STRUCT_STATIC
= 0,
53 * The last color is no color used for works which don't
54 * participate in workqueue flushing.
56 WORK_NR_COLORS
= (1 << WORK_STRUCT_COLOR_BITS
) - 1,
57 WORK_NO_COLOR
= WORK_NR_COLORS
,
59 /* not bound to any CPU, prefer the local CPU */
60 WORK_CPU_UNBOUND
= NR_CPUS
,
63 * Reserve 7 bits off of pwq pointer w/ debugobjects turned off.
64 * This makes pwqs aligned to 256 bytes and allows 15 workqueue
67 WORK_STRUCT_FLAG_BITS
= WORK_STRUCT_COLOR_SHIFT
+
68 WORK_STRUCT_COLOR_BITS
,
70 /* data contains off-queue information when !WORK_STRUCT_PWQ */
71 WORK_OFFQ_FLAG_BASE
= WORK_STRUCT_COLOR_SHIFT
,
73 __WORK_OFFQ_CANCELING
= WORK_OFFQ_FLAG_BASE
,
74 WORK_OFFQ_CANCELING
= (1 << __WORK_OFFQ_CANCELING
),
77 * When a work item is off queue, its high bits point to the last
78 * pool it was on. Cap at 31 bits and use the highest number to
79 * indicate that no pool is associated.
81 WORK_OFFQ_FLAG_BITS
= 1,
82 WORK_OFFQ_POOL_SHIFT
= WORK_OFFQ_FLAG_BASE
+ WORK_OFFQ_FLAG_BITS
,
83 WORK_OFFQ_LEFT
= BITS_PER_LONG
- WORK_OFFQ_POOL_SHIFT
,
84 WORK_OFFQ_POOL_BITS
= WORK_OFFQ_LEFT
<= 31 ? WORK_OFFQ_LEFT
: 31,
85 WORK_OFFQ_POOL_NONE
= (1LU << WORK_OFFQ_POOL_BITS
) - 1,
87 /* convenience constants */
88 WORK_STRUCT_FLAG_MASK
= (1UL << WORK_STRUCT_FLAG_BITS
) - 1,
89 WORK_STRUCT_WQ_DATA_MASK
= ~WORK_STRUCT_FLAG_MASK
,
90 WORK_STRUCT_NO_POOL
= (unsigned long)WORK_OFFQ_POOL_NONE
<< WORK_OFFQ_POOL_SHIFT
,
92 /* bit mask for work_busy() return values */
93 WORK_BUSY_PENDING
= 1 << 0,
94 WORK_BUSY_RUNNING
= 1 << 1,
96 /* maximum string length for set_worker_desc() */
102 struct list_head entry
;
104 #ifdef CONFIG_LOCKDEP
105 struct lockdep_map lockdep_map
;
109 #define WORK_DATA_INIT() ATOMIC_LONG_INIT((unsigned long)WORK_STRUCT_NO_POOL)
110 #define WORK_DATA_STATIC_INIT() \
111 ATOMIC_LONG_INIT((unsigned long)(WORK_STRUCT_NO_POOL | WORK_STRUCT_STATIC))
113 struct delayed_work
{
114 struct work_struct work
;
115 struct timer_list timer
;
117 /* target workqueue and CPU ->timer uses to queue ->work */
118 struct workqueue_struct
*wq
;
123 * struct workqueue_attrs - A struct for workqueue attributes.
125 * This can be used to change attributes of an unbound workqueue.
127 struct workqueue_attrs
{
134 * @cpumask: allowed CPUs
136 cpumask_var_t cpumask
;
139 * @no_numa: disable NUMA affinity
141 * Unlike other fields, ``no_numa`` isn't a property of a worker_pool. It
142 * only modifies how :c:func:`apply_workqueue_attrs` select pools and thus
143 * doesn't participate in pool hash calculations or equality comparisons.
148 static inline struct delayed_work
*to_delayed_work(struct work_struct
*work
)
150 return container_of(work
, struct delayed_work
, work
);
153 struct execute_work
{
154 struct work_struct work
;
157 #ifdef CONFIG_LOCKDEP
159 * NB: because we have to copy the lockdep_map, setting _key
160 * here is required, otherwise it could get initialised to the
161 * copy of the lockdep_map!
163 #define __WORK_INIT_LOCKDEP_MAP(n, k) \
164 .lockdep_map = STATIC_LOCKDEP_MAP_INIT(n, k),
166 #define __WORK_INIT_LOCKDEP_MAP(n, k)
169 #define __WORK_INITIALIZER(n, f) { \
170 .data = WORK_DATA_STATIC_INIT(), \
171 .entry = { &(n).entry, &(n).entry }, \
173 __WORK_INIT_LOCKDEP_MAP(#n, &(n)) \
176 #define __DELAYED_WORK_INITIALIZER(n, f, tflags) { \
177 .work = __WORK_INITIALIZER((n).work, (f)), \
178 .timer = __TIMER_INITIALIZER(delayed_work_timer_fn, \
179 0, (unsigned long)&(n), \
180 (tflags) | TIMER_IRQSAFE), \
183 #define DECLARE_WORK(n, f) \
184 struct work_struct n = __WORK_INITIALIZER(n, f)
186 #define DECLARE_DELAYED_WORK(n, f) \
187 struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, 0)
189 #define DECLARE_DEFERRABLE_WORK(n, f) \
190 struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, TIMER_DEFERRABLE)
192 #ifdef CONFIG_DEBUG_OBJECTS_WORK
193 extern void __init_work(struct work_struct
*work
, int onstack
);
194 extern void destroy_work_on_stack(struct work_struct
*work
);
195 extern void destroy_delayed_work_on_stack(struct delayed_work
*work
);
196 static inline unsigned int work_static(struct work_struct
*work
)
198 return *work_data_bits(work
) & WORK_STRUCT_STATIC
;
201 static inline void __init_work(struct work_struct
*work
, int onstack
) { }
202 static inline void destroy_work_on_stack(struct work_struct
*work
) { }
203 static inline void destroy_delayed_work_on_stack(struct delayed_work
*work
) { }
204 static inline unsigned int work_static(struct work_struct
*work
) { return 0; }
208 * initialize all of a work item in one go
210 * NOTE! No point in using "atomic_long_set()": using a direct
211 * assignment of the work data initializer allows the compiler
212 * to generate better code.
214 #ifdef CONFIG_LOCKDEP
215 #define __INIT_WORK(_work, _func, _onstack) \
217 static struct lock_class_key __key; \
219 __init_work((_work), _onstack); \
220 (_work)->data = (atomic_long_t) WORK_DATA_INIT(); \
221 lockdep_init_map(&(_work)->lockdep_map, #_work, &__key, 0); \
222 INIT_LIST_HEAD(&(_work)->entry); \
223 (_work)->func = (_func); \
226 #define __INIT_WORK(_work, _func, _onstack) \
228 __init_work((_work), _onstack); \
229 (_work)->data = (atomic_long_t) WORK_DATA_INIT(); \
230 INIT_LIST_HEAD(&(_work)->entry); \
231 (_work)->func = (_func); \
235 #define INIT_WORK(_work, _func) \
236 __INIT_WORK((_work), (_func), 0)
238 #define INIT_WORK_ONSTACK(_work, _func) \
239 __INIT_WORK((_work), (_func), 1)
241 #define __INIT_DELAYED_WORK(_work, _func, _tflags) \
243 INIT_WORK(&(_work)->work, (_func)); \
244 __setup_timer(&(_work)->timer, delayed_work_timer_fn, \
245 (unsigned long)(_work), \
246 (_tflags) | TIMER_IRQSAFE); \
249 #define __INIT_DELAYED_WORK_ONSTACK(_work, _func, _tflags) \
251 INIT_WORK_ONSTACK(&(_work)->work, (_func)); \
252 __setup_timer_on_stack(&(_work)->timer, \
253 delayed_work_timer_fn, \
254 (unsigned long)(_work), \
255 (_tflags) | TIMER_IRQSAFE); \
258 #define INIT_DELAYED_WORK(_work, _func) \
259 __INIT_DELAYED_WORK(_work, _func, 0)
261 #define INIT_DELAYED_WORK_ONSTACK(_work, _func) \
262 __INIT_DELAYED_WORK_ONSTACK(_work, _func, 0)
264 #define INIT_DEFERRABLE_WORK(_work, _func) \
265 __INIT_DELAYED_WORK(_work, _func, TIMER_DEFERRABLE)
267 #define INIT_DEFERRABLE_WORK_ONSTACK(_work, _func) \
268 __INIT_DELAYED_WORK_ONSTACK(_work, _func, TIMER_DEFERRABLE)
271 * work_pending - Find out whether a work item is currently pending
272 * @work: The work item in question
274 #define work_pending(work) \
275 test_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))
278 * delayed_work_pending - Find out whether a delayable work item is currently
280 * @w: The work item in question
282 #define delayed_work_pending(w) \
283 work_pending(&(w)->work)
286 * Workqueue flags and constants. For details, please refer to
287 * Documentation/core-api/workqueue.rst.
290 WQ_UNBOUND
= 1 << 1, /* not bound to any cpu */
291 WQ_FREEZABLE
= 1 << 2, /* freeze during suspend */
292 WQ_MEM_RECLAIM
= 1 << 3, /* may be used for memory reclaim */
293 WQ_HIGHPRI
= 1 << 4, /* high priority */
294 WQ_CPU_INTENSIVE
= 1 << 5, /* cpu intensive workqueue */
295 WQ_SYSFS
= 1 << 6, /* visible in sysfs, see wq_sysfs_register() */
298 * Per-cpu workqueues are generally preferred because they tend to
299 * show better performance thanks to cache locality. Per-cpu
300 * workqueues exclude the scheduler from choosing the CPU to
301 * execute the worker threads, which has an unfortunate side effect
302 * of increasing power consumption.
304 * The scheduler considers a CPU idle if it doesn't have any task
305 * to execute and tries to keep idle cores idle to conserve power;
306 * however, for example, a per-cpu work item scheduled from an
307 * interrupt handler on an idle CPU will force the scheduler to
308 * excute the work item on that CPU breaking the idleness, which in
309 * turn may lead to more scheduling choices which are sub-optimal
310 * in terms of power consumption.
312 * Workqueues marked with WQ_POWER_EFFICIENT are per-cpu by default
313 * but become unbound if workqueue.power_efficient kernel param is
314 * specified. Per-cpu workqueues which are identified to
315 * contribute significantly to power-consumption are identified and
316 * marked with this flag and enabling the power_efficient mode
317 * leads to noticeable power saving at the cost of small
318 * performance disadvantage.
320 * http://thread.gmane.org/gmane.linux.kernel/1480396
322 WQ_POWER_EFFICIENT
= 1 << 7,
324 __WQ_DRAINING
= 1 << 16, /* internal: workqueue is draining */
325 __WQ_ORDERED
= 1 << 17, /* internal: workqueue is ordered */
326 __WQ_LEGACY
= 1 << 18, /* internal: create*_workqueue() */
328 WQ_MAX_ACTIVE
= 512, /* I like 512, better ideas? */
329 WQ_MAX_UNBOUND_PER_CPU
= 4, /* 4 * #cpus for unbound wq */
330 WQ_DFL_ACTIVE
= WQ_MAX_ACTIVE
/ 2,
333 /* unbound wq's aren't per-cpu, scale max_active according to #cpus */
334 #define WQ_UNBOUND_MAX_ACTIVE \
335 max_t(int, WQ_MAX_ACTIVE, num_possible_cpus() * WQ_MAX_UNBOUND_PER_CPU)
338 * System-wide workqueues which are always present.
340 * system_wq is the one used by schedule[_delayed]_work[_on]().
341 * Multi-CPU multi-threaded. There are users which expect relatively
342 * short queue flush time. Don't queue works which can run for too
345 * system_highpri_wq is similar to system_wq but for work items which
346 * require WQ_HIGHPRI.
348 * system_long_wq is similar to system_wq but may host long running
349 * works. Queue flushing might take relatively long.
351 * system_unbound_wq is unbound workqueue. Workers are not bound to
352 * any specific CPU, not concurrency managed, and all queued works are
353 * executed immediately as long as max_active limit is not reached and
354 * resources are available.
356 * system_freezable_wq is equivalent to system_wq except that it's
359 * *_power_efficient_wq are inclined towards saving power and converted
360 * into WQ_UNBOUND variants if 'wq_power_efficient' is enabled; otherwise,
361 * they are same as their non-power-efficient counterparts - e.g.
362 * system_power_efficient_wq is identical to system_wq if
363 * 'wq_power_efficient' is disabled. See WQ_POWER_EFFICIENT for more info.
365 extern struct workqueue_struct
*system_wq
;
366 extern struct workqueue_struct
*system_highpri_wq
;
367 extern struct workqueue_struct
*system_long_wq
;
368 extern struct workqueue_struct
*system_unbound_wq
;
369 extern struct workqueue_struct
*system_freezable_wq
;
370 extern struct workqueue_struct
*system_power_efficient_wq
;
371 extern struct workqueue_struct
*system_freezable_power_efficient_wq
;
373 extern struct workqueue_struct
*
374 __alloc_workqueue_key(const char *fmt
, unsigned int flags
, int max_active
,
375 struct lock_class_key
*key
, const char *lock_name
, ...) __printf(1, 6);
378 * alloc_workqueue - allocate a workqueue
379 * @fmt: printf format for the name of the workqueue
381 * @max_active: max in-flight work items, 0 for default
382 * @args...: args for @fmt
384 * Allocate a workqueue with the specified parameters. For detailed
385 * information on WQ_* flags, please refer to
386 * Documentation/core-api/workqueue.rst.
388 * The __lock_name macro dance is to guarantee that single lock_class_key
389 * doesn't end up with different namesm, which isn't allowed by lockdep.
392 * Pointer to the allocated workqueue on success, %NULL on failure.
394 #ifdef CONFIG_LOCKDEP
395 #define alloc_workqueue(fmt, flags, max_active, args...) \
397 static struct lock_class_key __key; \
398 const char *__lock_name; \
400 __lock_name = #fmt#args; \
402 __alloc_workqueue_key((fmt), (flags), (max_active), \
403 &__key, __lock_name, ##args); \
406 #define alloc_workqueue(fmt, flags, max_active, args...) \
407 __alloc_workqueue_key((fmt), (flags), (max_active), \
412 * alloc_ordered_workqueue - allocate an ordered workqueue
413 * @fmt: printf format for the name of the workqueue
414 * @flags: WQ_* flags (only WQ_FREEZABLE and WQ_MEM_RECLAIM are meaningful)
415 * @args...: args for @fmt
417 * Allocate an ordered workqueue. An ordered workqueue executes at
418 * most one work item at any given time in the queued order. They are
419 * implemented as unbound workqueues with @max_active of one.
422 * Pointer to the allocated workqueue on success, %NULL on failure.
424 #define alloc_ordered_workqueue(fmt, flags, args...) \
425 alloc_workqueue(fmt, WQ_UNBOUND | __WQ_ORDERED | (flags), 1, ##args)
427 #define create_workqueue(name) \
428 alloc_workqueue("%s", __WQ_LEGACY | WQ_MEM_RECLAIM, 1, (name))
429 #define create_freezable_workqueue(name) \
430 alloc_workqueue("%s", __WQ_LEGACY | WQ_FREEZABLE | WQ_UNBOUND | \
431 WQ_MEM_RECLAIM, 1, (name))
432 #define create_singlethread_workqueue(name) \
433 alloc_ordered_workqueue("%s", __WQ_LEGACY | WQ_MEM_RECLAIM, name)
435 extern void destroy_workqueue(struct workqueue_struct
*wq
);
437 struct workqueue_attrs
*alloc_workqueue_attrs(gfp_t gfp_mask
);
438 void free_workqueue_attrs(struct workqueue_attrs
*attrs
);
439 int apply_workqueue_attrs(struct workqueue_struct
*wq
,
440 const struct workqueue_attrs
*attrs
);
441 int workqueue_set_unbound_cpumask(cpumask_var_t cpumask
);
443 extern bool queue_work_on(int cpu
, struct workqueue_struct
*wq
,
444 struct work_struct
*work
);
445 extern bool queue_delayed_work_on(int cpu
, struct workqueue_struct
*wq
,
446 struct delayed_work
*work
, unsigned long delay
);
447 extern bool mod_delayed_work_on(int cpu
, struct workqueue_struct
*wq
,
448 struct delayed_work
*dwork
, unsigned long delay
);
450 extern void flush_workqueue(struct workqueue_struct
*wq
);
451 extern void drain_workqueue(struct workqueue_struct
*wq
);
453 extern int schedule_on_each_cpu(work_func_t func
);
455 int execute_in_process_context(work_func_t fn
, struct execute_work
*);
457 extern bool flush_work(struct work_struct
*work
);
458 extern bool cancel_work(struct work_struct
*work
);
459 extern bool cancel_work_sync(struct work_struct
*work
);
461 extern bool flush_delayed_work(struct delayed_work
*dwork
);
462 extern bool cancel_delayed_work(struct delayed_work
*dwork
);
463 extern bool cancel_delayed_work_sync(struct delayed_work
*dwork
);
465 extern void workqueue_set_max_active(struct workqueue_struct
*wq
,
467 extern bool current_is_workqueue_rescuer(void);
468 extern bool workqueue_congested(int cpu
, struct workqueue_struct
*wq
);
469 extern unsigned int work_busy(struct work_struct
*work
);
470 extern __printf(1, 2) void set_worker_desc(const char *fmt
, ...);
471 extern void print_worker_info(const char *log_lvl
, struct task_struct
*task
);
472 extern void show_workqueue_state(void);
475 * queue_work - queue work on a workqueue
476 * @wq: workqueue to use
477 * @work: work to queue
479 * Returns %false if @work was already on a queue, %true otherwise.
481 * We queue the work to the CPU on which it was submitted, but if the CPU dies
482 * it can be processed by another CPU.
484 static inline bool queue_work(struct workqueue_struct
*wq
,
485 struct work_struct
*work
)
487 return queue_work_on(WORK_CPU_UNBOUND
, wq
, work
);
491 * queue_delayed_work - queue work on a workqueue after delay
492 * @wq: workqueue to use
493 * @dwork: delayable work to queue
494 * @delay: number of jiffies to wait before queueing
496 * Equivalent to queue_delayed_work_on() but tries to use the local CPU.
498 static inline bool queue_delayed_work(struct workqueue_struct
*wq
,
499 struct delayed_work
*dwork
,
502 return queue_delayed_work_on(WORK_CPU_UNBOUND
, wq
, dwork
, delay
);
506 * mod_delayed_work - modify delay of or queue a delayed work
507 * @wq: workqueue to use
508 * @dwork: work to queue
509 * @delay: number of jiffies to wait before queueing
511 * mod_delayed_work_on() on local CPU.
513 static inline bool mod_delayed_work(struct workqueue_struct
*wq
,
514 struct delayed_work
*dwork
,
517 return mod_delayed_work_on(WORK_CPU_UNBOUND
, wq
, dwork
, delay
);
521 * schedule_work_on - put work task on a specific cpu
522 * @cpu: cpu to put the work task on
523 * @work: job to be done
525 * This puts a job on a specific cpu
527 static inline bool schedule_work_on(int cpu
, struct work_struct
*work
)
529 return queue_work_on(cpu
, system_wq
, work
);
533 * schedule_work - put work task in global workqueue
534 * @work: job to be done
536 * Returns %false if @work was already on the kernel-global workqueue and
539 * This puts a job in the kernel-global workqueue if it was not already
540 * queued and leaves it in the same position on the kernel-global
541 * workqueue otherwise.
543 static inline bool schedule_work(struct work_struct
*work
)
545 return queue_work(system_wq
, work
);
549 * flush_scheduled_work - ensure that any scheduled work has run to completion.
551 * Forces execution of the kernel-global workqueue and blocks until its
554 * Think twice before calling this function! It's very easy to get into
555 * trouble if you don't take great care. Either of the following situations
556 * will lead to deadlock:
558 * One of the work items currently on the workqueue needs to acquire
559 * a lock held by your code or its caller.
561 * Your code is running in the context of a work routine.
563 * They will be detected by lockdep when they occur, but the first might not
564 * occur very often. It depends on what work items are on the workqueue and
565 * what locks they need, which you have no control over.
567 * In most situations flushing the entire workqueue is overkill; you merely
568 * need to know that a particular work item isn't queued and isn't running.
569 * In such cases you should use cancel_delayed_work_sync() or
570 * cancel_work_sync() instead.
572 static inline void flush_scheduled_work(void)
574 flush_workqueue(system_wq
);
578 * schedule_delayed_work_on - queue work in global workqueue on CPU after delay
580 * @dwork: job to be done
581 * @delay: number of jiffies to wait
583 * After waiting for a given time this puts a job in the kernel-global
584 * workqueue on the specified CPU.
586 static inline bool schedule_delayed_work_on(int cpu
, struct delayed_work
*dwork
,
589 return queue_delayed_work_on(cpu
, system_wq
, dwork
, delay
);
593 * schedule_delayed_work - put work task in global workqueue after delay
594 * @dwork: job to be done
595 * @delay: number of jiffies to wait or 0 for immediate execution
597 * After waiting for a given time this puts a job in the kernel-global
600 static inline bool schedule_delayed_work(struct delayed_work
*dwork
,
603 return queue_delayed_work(system_wq
, dwork
, delay
);
607 static inline long work_on_cpu(int cpu
, long (*fn
)(void *), void *arg
)
611 static inline long work_on_cpu_safe(int cpu
, long (*fn
)(void *), void *arg
)
616 long work_on_cpu(int cpu
, long (*fn
)(void *), void *arg
);
617 long work_on_cpu_safe(int cpu
, long (*fn
)(void *), void *arg
);
618 #endif /* CONFIG_SMP */
620 #ifdef CONFIG_FREEZER
621 extern void freeze_workqueues_begin(void);
622 extern bool freeze_workqueues_busy(void);
623 extern void thaw_workqueues(void);
624 #endif /* CONFIG_FREEZER */
627 int workqueue_sysfs_register(struct workqueue_struct
*wq
);
628 #else /* CONFIG_SYSFS */
629 static inline int workqueue_sysfs_register(struct workqueue_struct
*wq
)
631 #endif /* CONFIG_SYSFS */
633 #ifdef CONFIG_WQ_WATCHDOG
634 void wq_watchdog_touch(int cpu
);
635 #else /* CONFIG_WQ_WATCHDOG */
636 static inline void wq_watchdog_touch(int cpu
) { }
637 #endif /* CONFIG_WQ_WATCHDOG */
640 int workqueue_prepare_cpu(unsigned int cpu
);
641 int workqueue_online_cpu(unsigned int cpu
);
642 int workqueue_offline_cpu(unsigned int cpu
);
645 int __init
workqueue_init_early(void);
646 int __init
workqueue_init(void);