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,
60 WORK_CPU_UNBOUND = NR_CPUS,
61 WORK_CPU_END = NR_CPUS + 1,
64 * Reserve 7 bits off of pwq pointer w/ debugobjects turned off.
65 * This makes pwqs aligned to 256 bytes and allows 15 workqueue
68 WORK_STRUCT_FLAG_BITS = WORK_STRUCT_COLOR_SHIFT +
69 WORK_STRUCT_COLOR_BITS,
71 /* data contains off-queue information when !WORK_STRUCT_PWQ */
72 WORK_OFFQ_FLAG_BASE = WORK_STRUCT_COLOR_SHIFT,
74 WORK_OFFQ_CANCELING = (1 << WORK_OFFQ_FLAG_BASE),
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(WORK_STRUCT_NO_POOL)
110 #define WORK_DATA_STATIC_INIT() \
111 ATOMIC_LONG_INIT(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 * A struct for workqueue attributes. This can be used to change
124 * attributes of an unbound workqueue.
126 * Unlike other fields, ->no_numa isn't a property of a worker_pool. It
127 * only modifies how apply_workqueue_attrs() select pools and thus doesn't
128 * participate in pool hash calculations or equality comparisons.
130 struct workqueue_attrs {
131 int nice; /* nice level */
132 cpumask_var_t cpumask; /* allowed CPUs */
133 bool no_numa; /* disable NUMA affinity */
136 static inline struct delayed_work *to_delayed_work(struct work_struct *work)
138 return container_of(work, struct delayed_work, work);
141 struct execute_work {
142 struct work_struct work;
145 #ifdef CONFIG_LOCKDEP
147 * NB: because we have to copy the lockdep_map, setting _key
148 * here is required, otherwise it could get initialised to the
149 * copy of the lockdep_map!
151 #define __WORK_INIT_LOCKDEP_MAP(n, k) \
152 .lockdep_map = STATIC_LOCKDEP_MAP_INIT(n, k),
154 #define __WORK_INIT_LOCKDEP_MAP(n, k)
157 #define __WORK_INITIALIZER(n, f) { \
158 .data = WORK_DATA_STATIC_INIT(), \
159 .entry = { &(n).entry, &(n).entry }, \
161 __WORK_INIT_LOCKDEP_MAP(#n, &(n)) \
164 #define __DELAYED_WORK_INITIALIZER(n, f, tflags) { \
165 .work = __WORK_INITIALIZER((n).work, (f)), \
166 .timer = __TIMER_INITIALIZER(delayed_work_timer_fn, \
167 0, (unsigned long)&(n), \
168 (tflags) | TIMER_IRQSAFE), \
171 #define DECLARE_WORK(n, f) \
172 struct work_struct n = __WORK_INITIALIZER(n, f)
174 #define DECLARE_DELAYED_WORK(n, f) \
175 struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, 0)
177 #define DECLARE_DEFERRABLE_WORK(n, f) \
178 struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, TIMER_DEFERRABLE)
180 #ifdef CONFIG_DEBUG_OBJECTS_WORK
181 extern void __init_work(struct work_struct *work, int onstack);
182 extern void destroy_work_on_stack(struct work_struct *work);
183 static inline unsigned int work_static(struct work_struct *work)
185 return *work_data_bits(work) & WORK_STRUCT_STATIC;
188 static inline void __init_work(struct work_struct *work, int onstack) { }
189 static inline void destroy_work_on_stack(struct work_struct *work) { }
190 static inline unsigned int work_static(struct work_struct *work) { return 0; }
194 * initialize all of a work item in one go
196 * NOTE! No point in using "atomic_long_set()": using a direct
197 * assignment of the work data initializer allows the compiler
198 * to generate better code.
200 #ifdef CONFIG_LOCKDEP
201 #define __INIT_WORK(_work, _func, _onstack) \
203 static struct lock_class_key __key; \
205 __init_work((_work), _onstack); \
206 (_work)->data = (atomic_long_t) WORK_DATA_INIT(); \
207 lockdep_init_map(&(_work)->lockdep_map, #_work, &__key, 0); \
208 INIT_LIST_HEAD(&(_work)->entry); \
209 (_work)->func = (_func); \
212 #define __INIT_WORK(_work, _func, _onstack) \
214 __init_work((_work), _onstack); \
215 (_work)->data = (atomic_long_t) WORK_DATA_INIT(); \
216 INIT_LIST_HEAD(&(_work)->entry); \
217 (_work)->func = (_func); \
221 #define INIT_WORK(_work, _func) \
223 __INIT_WORK((_work), (_func), 0); \
226 #define INIT_WORK_ONSTACK(_work, _func) \
228 __INIT_WORK((_work), (_func), 1); \
231 #define __INIT_DELAYED_WORK(_work, _func, _tflags) \
233 INIT_WORK(&(_work)->work, (_func)); \
234 __setup_timer(&(_work)->timer, delayed_work_timer_fn, \
235 (unsigned long)(_work), \
236 (_tflags) | TIMER_IRQSAFE); \
239 #define __INIT_DELAYED_WORK_ONSTACK(_work, _func, _tflags) \
241 INIT_WORK_ONSTACK(&(_work)->work, (_func)); \
242 __setup_timer_on_stack(&(_work)->timer, \
243 delayed_work_timer_fn, \
244 (unsigned long)(_work), \
245 (_tflags) | TIMER_IRQSAFE); \
248 #define INIT_DELAYED_WORK(_work, _func) \
249 __INIT_DELAYED_WORK(_work, _func, 0)
251 #define INIT_DELAYED_WORK_ONSTACK(_work, _func) \
252 __INIT_DELAYED_WORK_ONSTACK(_work, _func, 0)
254 #define INIT_DEFERRABLE_WORK(_work, _func) \
255 __INIT_DELAYED_WORK(_work, _func, TIMER_DEFERRABLE)
257 #define INIT_DEFERRABLE_WORK_ONSTACK(_work, _func) \
258 __INIT_DELAYED_WORK_ONSTACK(_work, _func, TIMER_DEFERRABLE)
261 * work_pending - Find out whether a work item is currently pending
262 * @work: The work item in question
264 #define work_pending(work) \
265 test_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))
268 * delayed_work_pending - Find out whether a delayable work item is currently
270 * @work: The work item in question
272 #define delayed_work_pending(w) \
273 work_pending(&(w)->work)
276 * work_clear_pending - for internal use only, mark a work item as not pending
277 * @work: The work item in question
279 #define work_clear_pending(work) \
280 clear_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))
283 * Workqueue flags and constants. For details, please refer to
284 * Documentation/workqueue.txt.
288 * All wqs are now non-reentrant making the following flag
289 * meaningless. Will be removed.
291 WQ_NON_REENTRANT = 1 << 0, /* DEPRECATED */
293 WQ_UNBOUND = 1 << 1, /* not bound to any cpu */
294 WQ_FREEZABLE = 1 << 2, /* freeze during suspend */
295 WQ_MEM_RECLAIM = 1 << 3, /* may be used for memory reclaim */
296 WQ_HIGHPRI = 1 << 4, /* high priority */
297 WQ_CPU_INTENSIVE = 1 << 5, /* cpu intensive workqueue */
298 WQ_SYSFS = 1 << 6, /* visible in sysfs, see wq_sysfs_register() */
301 * Per-cpu workqueues are generally preferred because they tend to
302 * show better performance thanks to cache locality. Per-cpu
303 * workqueues exclude the scheduler from choosing the CPU to
304 * execute the worker threads, which has an unfortunate side effect
305 * of increasing power consumption.
307 * The scheduler considers a CPU idle if it doesn't have any task
308 * to execute and tries to keep idle cores idle to conserve power;
309 * however, for example, a per-cpu work item scheduled from an
310 * interrupt handler on an idle CPU will force the scheduler to
311 * excute the work item on that CPU breaking the idleness, which in
312 * turn may lead to more scheduling choices which are sub-optimal
313 * in terms of power consumption.
315 * Workqueues marked with WQ_POWER_EFFICIENT are per-cpu by default
316 * but become unbound if workqueue.power_efficient kernel param is
317 * specified. Per-cpu workqueues which are identified to
318 * contribute significantly to power-consumption are identified and
319 * marked with this flag and enabling the power_efficient mode
320 * leads to noticeable power saving at the cost of small
321 * performance disadvantage.
323 * http://thread.gmane.org/gmane.linux.kernel/1480396
325 WQ_POWER_EFFICIENT = 1 << 7,
327 __WQ_DRAINING = 1 << 16, /* internal: workqueue is draining */
328 __WQ_ORDERED = 1 << 17, /* internal: workqueue is ordered */
330 WQ_MAX_ACTIVE = 512, /* I like 512, better ideas? */
331 WQ_MAX_UNBOUND_PER_CPU = 4, /* 4 * #cpus for unbound wq */
332 WQ_DFL_ACTIVE = WQ_MAX_ACTIVE / 2,
335 /* unbound wq's aren't per-cpu, scale max_active according to #cpus */
336 #define WQ_UNBOUND_MAX_ACTIVE \
337 max_t(int, WQ_MAX_ACTIVE, num_possible_cpus() * WQ_MAX_UNBOUND_PER_CPU)
340 * System-wide workqueues which are always present.
342 * system_wq is the one used by schedule[_delayed]_work[_on]().
343 * Multi-CPU multi-threaded. There are users which expect relatively
344 * short queue flush time. Don't queue works which can run for too
347 * system_long_wq is similar to system_wq but may host long running
348 * works. Queue flushing might take relatively long.
350 * system_unbound_wq is unbound workqueue. Workers are not bound to
351 * any specific CPU, not concurrency managed, and all queued works are
352 * executed immediately as long as max_active limit is not reached and
353 * resources are available.
355 * system_freezable_wq is equivalent to system_wq except that it's
358 * *_power_efficient_wq are inclined towards saving power and converted
359 * into WQ_UNBOUND variants if 'wq_power_efficient' is enabled; otherwise,
360 * they are same as their non-power-efficient counterparts - e.g.
361 * system_power_efficient_wq is identical to system_wq if
362 * 'wq_power_efficient' is disabled. See WQ_POWER_EFFICIENT for more info.
364 extern struct workqueue_struct *system_wq;
365 extern struct workqueue_struct *system_long_wq;
366 extern struct workqueue_struct *system_unbound_wq;
367 extern struct workqueue_struct *system_freezable_wq;
368 extern struct workqueue_struct *system_power_efficient_wq;
369 extern struct workqueue_struct *system_freezable_power_efficient_wq;
371 static inline struct workqueue_struct * __deprecated __system_nrt_wq(void)
376 static inline struct workqueue_struct * __deprecated __system_nrt_freezable_wq(void)
378 return system_freezable_wq;
381 /* equivlalent to system_wq and system_freezable_wq, deprecated */
382 #define system_nrt_wq __system_nrt_wq()
383 #define system_nrt_freezable_wq __system_nrt_freezable_wq()
385 extern struct workqueue_struct *
386 __alloc_workqueue_key(const char *fmt, unsigned int flags, int max_active,
387 struct lock_class_key *key, const char *lock_name, ...) __printf(1, 6);
390 * alloc_workqueue - allocate a workqueue
391 * @fmt: printf format for the name of the workqueue
393 * @max_active: max in-flight work items, 0 for default
394 * @args: args for @fmt
396 * Allocate a workqueue with the specified parameters. For detailed
397 * information on WQ_* flags, please refer to Documentation/workqueue.txt.
399 * The __lock_name macro dance is to guarantee that single lock_class_key
400 * doesn't end up with different namesm, which isn't allowed by lockdep.
403 * Pointer to the allocated workqueue on success, %NULL on failure.
405 #ifdef CONFIG_LOCKDEP
406 #define alloc_workqueue(fmt, flags, max_active, args...) \
408 static struct lock_class_key __key; \
409 const char *__lock_name; \
411 __lock_name = #fmt#args; \
413 __alloc_workqueue_key((fmt), (flags), (max_active), \
414 &__key, __lock_name, ##args); \
417 #define alloc_workqueue(fmt, flags, max_active, args...) \
418 __alloc_workqueue_key((fmt), (flags), (max_active), \
423 * alloc_ordered_workqueue - allocate an ordered workqueue
424 * @fmt: printf format for the name of the workqueue
425 * @flags: WQ_* flags (only WQ_FREEZABLE and WQ_MEM_RECLAIM are meaningful)
426 * @args: args for @fmt
428 * Allocate an ordered workqueue. An ordered workqueue executes at
429 * most one work item at any given time in the queued order. They are
430 * implemented as unbound workqueues with @max_active of one.
433 * Pointer to the allocated workqueue on success, %NULL on failure.
435 #define alloc_ordered_workqueue(fmt, flags, args...) \
436 alloc_workqueue(fmt, WQ_UNBOUND | __WQ_ORDERED | (flags), 1, ##args)
438 #define create_workqueue(name) \
439 alloc_workqueue("%s", WQ_MEM_RECLAIM, 1, (name))
440 #define create_freezable_workqueue(name) \
441 alloc_workqueue("%s", WQ_FREEZABLE | WQ_UNBOUND | WQ_MEM_RECLAIM, \
443 #define create_singlethread_workqueue(name) \
444 alloc_workqueue("%s", WQ_UNBOUND | WQ_MEM_RECLAIM, 1, (name))
446 extern void destroy_workqueue(struct workqueue_struct *wq);
448 struct workqueue_attrs *alloc_workqueue_attrs(gfp_t gfp_mask);
449 void free_workqueue_attrs(struct workqueue_attrs *attrs);
450 int apply_workqueue_attrs(struct workqueue_struct *wq,
451 const struct workqueue_attrs *attrs);
453 extern bool queue_work_on(int cpu, struct workqueue_struct *wq,
454 struct work_struct *work);
455 extern bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
456 struct delayed_work *work, unsigned long delay);
457 extern bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq,
458 struct delayed_work *dwork, unsigned long delay);
460 extern void flush_workqueue(struct workqueue_struct *wq);
461 extern void drain_workqueue(struct workqueue_struct *wq);
462 extern void flush_scheduled_work(void);
464 extern int schedule_on_each_cpu(work_func_t func);
466 int execute_in_process_context(work_func_t fn, struct execute_work *);
468 extern bool flush_work(struct work_struct *work);
469 extern bool cancel_work_sync(struct work_struct *work);
471 extern bool flush_delayed_work(struct delayed_work *dwork);
472 extern bool cancel_delayed_work(struct delayed_work *dwork);
473 extern bool cancel_delayed_work_sync(struct delayed_work *dwork);
475 extern void workqueue_set_max_active(struct workqueue_struct *wq,
477 extern bool current_is_workqueue_rescuer(void);
478 extern bool workqueue_congested(int cpu, struct workqueue_struct *wq);
479 extern unsigned int work_busy(struct work_struct *work);
480 extern __printf(1, 2) void set_worker_desc(const char *fmt, ...);
481 extern void print_worker_info(const char *log_lvl, struct task_struct *task);
484 * queue_work - queue work on a workqueue
485 * @wq: workqueue to use
486 * @work: work to queue
488 * Returns %false if @work was already on a queue, %true otherwise.
490 * We queue the work to the CPU on which it was submitted, but if the CPU dies
491 * it can be processed by another CPU.
493 static inline bool queue_work(struct workqueue_struct *wq,
494 struct work_struct *work)
496 return queue_work_on(WORK_CPU_UNBOUND, wq, work);
500 * queue_delayed_work - queue work on a workqueue after delay
501 * @wq: workqueue to use
502 * @dwork: delayable work to queue
503 * @delay: number of jiffies to wait before queueing
505 * Equivalent to queue_delayed_work_on() but tries to use the local CPU.
507 static inline bool queue_delayed_work(struct workqueue_struct *wq,
508 struct delayed_work *dwork,
511 return queue_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay);
515 * mod_delayed_work - modify delay of or queue a delayed work
516 * @wq: workqueue to use
517 * @dwork: work to queue
518 * @delay: number of jiffies to wait before queueing
520 * mod_delayed_work_on() on local CPU.
522 static inline bool mod_delayed_work(struct workqueue_struct *wq,
523 struct delayed_work *dwork,
526 return mod_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay);
530 * schedule_work_on - put work task on a specific cpu
531 * @cpu: cpu to put the work task on
532 * @work: job to be done
534 * This puts a job on a specific cpu
536 static inline bool schedule_work_on(int cpu, struct work_struct *work)
538 return queue_work_on(cpu, system_wq, work);
542 * schedule_work - put work task in global workqueue
543 * @work: job to be done
545 * Returns %false if @work was already on the kernel-global workqueue and
548 * This puts a job in the kernel-global workqueue if it was not already
549 * queued and leaves it in the same position on the kernel-global
550 * workqueue otherwise.
552 static inline bool schedule_work(struct work_struct *work)
554 return queue_work(system_wq, work);
558 * schedule_delayed_work_on - queue work in global workqueue on CPU after delay
560 * @dwork: job to be done
561 * @delay: number of jiffies to wait
563 * After waiting for a given time this puts a job in the kernel-global
564 * workqueue on the specified CPU.
566 static inline bool schedule_delayed_work_on(int cpu, struct delayed_work *dwork,
569 return queue_delayed_work_on(cpu, system_wq, dwork, delay);
573 * schedule_delayed_work - put work task in global workqueue after delay
574 * @dwork: job to be done
575 * @delay: number of jiffies to wait or 0 for immediate execution
577 * After waiting for a given time this puts a job in the kernel-global
580 static inline bool schedule_delayed_work(struct delayed_work *dwork,
583 return queue_delayed_work(system_wq, dwork, delay);
587 * keventd_up - is workqueue initialized yet?
589 static inline bool keventd_up(void)
591 return system_wq != NULL;
594 /* used to be different but now identical to flush_work(), deprecated */
595 static inline bool __deprecated flush_work_sync(struct work_struct *work)
597 return flush_work(work);
600 /* used to be different but now identical to flush_delayed_work(), deprecated */
601 static inline bool __deprecated flush_delayed_work_sync(struct delayed_work *dwork)
603 return flush_delayed_work(dwork);
607 static inline long work_on_cpu(int cpu, long (*fn)(void *), void *arg)
612 long work_on_cpu(int cpu, long (*fn)(void *), void *arg);
613 #endif /* CONFIG_SMP */
615 #ifdef CONFIG_FREEZER
616 extern void freeze_workqueues_begin(void);
617 extern bool freeze_workqueues_busy(void);
618 extern void thaw_workqueues(void);
619 #endif /* CONFIG_FREEZER */
622 int workqueue_sysfs_register(struct workqueue_struct *wq);
623 #else /* CONFIG_SYSFS */
624 static inline int workqueue_sysfs_register(struct workqueue_struct *wq)
626 #endif /* CONFIG_SYSFS */