blob: d9a1a480e920c10ee720de07652e18e95ee6ecbd [file] [log] [blame]
Greg Kroah-Hartmanb2441312017-11-01 15:07:57 +01001/* SPDX-License-Identifier: GPL-2.0 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002/*
3 * workqueue.h --- work queue handling for Linux.
4 */
5
6#ifndef _LINUX_WORKQUEUE_H
7#define _LINUX_WORKQUEUE_H
8
9#include <linux/timer.h>
10#include <linux/linkage.h>
11#include <linux/bitops.h>
Johannes Berg4e6045f2007-10-18 23:39:55 -070012#include <linux/lockdep.h>
Tejun Heo7a22ad72010-06-29 10:07:13 +020013#include <linux/threads.h>
Arun Sharma600634972011-07-26 16:09:06 -070014#include <linux/atomic.h>
Tejun Heo7a4e3442013-03-12 11:30:00 -070015#include <linux/cpumask.h>
Tejun Heo05f0fe62018-03-14 12:45:13 -070016#include <linux/rcupdate.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070017
18struct workqueue_struct;
19
David Howells65f27f32006-11-22 14:55:48 +000020struct work_struct;
21typedef void (*work_func_t)(struct work_struct *work);
Kees Cook8c20feb2017-10-04 16:27:07 -070022void delayed_work_timer_fn(struct timer_list *t);
David Howells6bb49e52006-11-22 14:54:45 +000023
Linus Torvaldsa08727b2006-12-16 09:53:50 -080024/*
25 * The first word is the work queue pointer and the flags rolled into
26 * one
27 */
28#define work_data_bits(work) ((unsigned long *)(&(work)->data))
29
Tejun Heo22df02b2010-06-29 10:07:10 +020030enum {
31 WORK_STRUCT_PENDING_BIT = 0, /* work item is pending execution */
Tejun Heo8a2e8e5d2010-08-25 10:33:56 +020032 WORK_STRUCT_DELAYED_BIT = 1, /* work item is delayed */
Tejun Heo112202d2013-02-13 19:29:12 -080033 WORK_STRUCT_PWQ_BIT = 2, /* data points to pwq */
Tejun Heo8a2e8e5d2010-08-25 10:33:56 +020034 WORK_STRUCT_LINKED_BIT = 3, /* next work is linked to this one */
Tejun Heo22df02b2010-06-29 10:07:10 +020035#ifdef CONFIG_DEBUG_OBJECTS_WORK
Tejun Heo8a2e8e5d2010-08-25 10:33:56 +020036 WORK_STRUCT_STATIC_BIT = 4, /* static initializer (debugobjects) */
37 WORK_STRUCT_COLOR_SHIFT = 5, /* color for workqueue flushing */
Tejun Heo0f900042010-06-29 10:07:11 +020038#else
Tejun Heo8a2e8e5d2010-08-25 10:33:56 +020039 WORK_STRUCT_COLOR_SHIFT = 4, /* color for workqueue flushing */
Tejun Heo22df02b2010-06-29 10:07:10 +020040#endif
41
Tejun Heo73f53c42010-06-29 10:07:11 +020042 WORK_STRUCT_COLOR_BITS = 4,
43
Tejun Heo22df02b2010-06-29 10:07:10 +020044 WORK_STRUCT_PENDING = 1 << WORK_STRUCT_PENDING_BIT,
Tejun Heo8a2e8e5d2010-08-25 10:33:56 +020045 WORK_STRUCT_DELAYED = 1 << WORK_STRUCT_DELAYED_BIT,
Tejun Heo112202d2013-02-13 19:29:12 -080046 WORK_STRUCT_PWQ = 1 << WORK_STRUCT_PWQ_BIT,
Tejun Heoaffee4b2010-06-29 10:07:12 +020047 WORK_STRUCT_LINKED = 1 << WORK_STRUCT_LINKED_BIT,
Tejun Heo22df02b2010-06-29 10:07:10 +020048#ifdef CONFIG_DEBUG_OBJECTS_WORK
49 WORK_STRUCT_STATIC = 1 << WORK_STRUCT_STATIC_BIT,
50#else
51 WORK_STRUCT_STATIC = 0,
52#endif
53
Tejun Heo73f53c42010-06-29 10:07:11 +020054 /*
55 * The last color is no color used for works which don't
56 * participate in workqueue flushing.
57 */
58 WORK_NR_COLORS = (1 << WORK_STRUCT_COLOR_BITS) - 1,
59 WORK_NO_COLOR = WORK_NR_COLORS,
60
Lai Jiangshan79bc2512014-05-22 16:43:44 +080061 /* not bound to any CPU, prefer the local CPU */
Tejun Heof3421792010-07-02 10:03:51 +020062 WORK_CPU_UNBOUND = NR_CPUS,
Tejun Heobdbc5dd2010-07-02 10:03:51 +020063
Tejun Heo73f53c42010-06-29 10:07:11 +020064 /*
Tejun Heo112202d2013-02-13 19:29:12 -080065 * Reserve 7 bits off of pwq pointer w/ debugobjects turned off.
66 * This makes pwqs aligned to 256 bytes and allows 15 workqueue
67 * flush colors.
Tejun Heo73f53c42010-06-29 10:07:11 +020068 */
69 WORK_STRUCT_FLAG_BITS = WORK_STRUCT_COLOR_SHIFT +
70 WORK_STRUCT_COLOR_BITS,
71
Tejun Heo112202d2013-02-13 19:29:12 -080072 /* data contains off-queue information when !WORK_STRUCT_PWQ */
Lai Jiangshan45d95502013-02-19 12:17:01 -080073 WORK_OFFQ_FLAG_BASE = WORK_STRUCT_COLOR_SHIFT,
Tejun Heobbb68df2012-08-03 10:30:46 -070074
Tejun Heo8603e1b32015-03-05 08:04:13 -050075 __WORK_OFFQ_CANCELING = WORK_OFFQ_FLAG_BASE,
76 WORK_OFFQ_CANCELING = (1 << __WORK_OFFQ_CANCELING),
Tejun Heobbb68df2012-08-03 10:30:46 -070077
Tejun Heo715b06b2013-01-24 11:01:33 -080078 /*
79 * When a work item is off queue, its high bits point to the last
Tejun Heo7c3eed52013-01-24 11:01:33 -080080 * pool it was on. Cap at 31 bits and use the highest number to
81 * indicate that no pool is associated.
Tejun Heo715b06b2013-01-24 11:01:33 -080082 */
Tejun Heobbb68df2012-08-03 10:30:46 -070083 WORK_OFFQ_FLAG_BITS = 1,
Tejun Heo7c3eed52013-01-24 11:01:33 -080084 WORK_OFFQ_POOL_SHIFT = WORK_OFFQ_FLAG_BASE + WORK_OFFQ_FLAG_BITS,
85 WORK_OFFQ_LEFT = BITS_PER_LONG - WORK_OFFQ_POOL_SHIFT,
86 WORK_OFFQ_POOL_BITS = WORK_OFFQ_LEFT <= 31 ? WORK_OFFQ_LEFT : 31,
87 WORK_OFFQ_POOL_NONE = (1LU << WORK_OFFQ_POOL_BITS) - 1,
Tejun Heob5490072012-08-03 10:30:46 -070088
89 /* convenience constants */
Tejun Heo0f900042010-06-29 10:07:11 +020090 WORK_STRUCT_FLAG_MASK = (1UL << WORK_STRUCT_FLAG_BITS) - 1,
Tejun Heo22df02b2010-06-29 10:07:10 +020091 WORK_STRUCT_WQ_DATA_MASK = ~WORK_STRUCT_FLAG_MASK,
Tejun Heo7c3eed52013-01-24 11:01:33 -080092 WORK_STRUCT_NO_POOL = (unsigned long)WORK_OFFQ_POOL_NONE << WORK_OFFQ_POOL_SHIFT,
Tejun Heodcd989c2010-06-29 10:07:14 +020093
94 /* bit mask for work_busy() return values */
95 WORK_BUSY_PENDING = 1 << 0,
96 WORK_BUSY_RUNNING = 1 << 1,
Tejun Heo3d1cb202013-04-30 15:27:22 -070097
98 /* maximum string length for set_worker_desc() */
99 WORKER_DESC_LEN = 24,
Tejun Heo22df02b2010-06-29 10:07:10 +0200100};
101
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102struct work_struct {
Linus Torvaldsa08727b2006-12-16 09:53:50 -0800103 atomic_long_t data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700104 struct list_head entry;
David Howells6bb49e52006-11-22 14:54:45 +0000105 work_func_t func;
Johannes Berg4e6045f2007-10-18 23:39:55 -0700106#ifdef CONFIG_LOCKDEP
107 struct lockdep_map lockdep_map;
108#endif
David Howells52bad642006-11-22 14:54:01 +0000109};
110
Arnd Bergmanna45463c2017-02-01 18:01:17 +0100111#define WORK_DATA_INIT() ATOMIC_LONG_INIT((unsigned long)WORK_STRUCT_NO_POOL)
Tejun Heo7a22ad72010-06-29 10:07:13 +0200112#define WORK_DATA_STATIC_INIT() \
Arnd Bergmanna45463c2017-02-01 18:01:17 +0100113 ATOMIC_LONG_INIT((unsigned long)(WORK_STRUCT_NO_POOL | WORK_STRUCT_STATIC))
Linus Torvaldsa08727b2006-12-16 09:53:50 -0800114
David Howells52bad642006-11-22 14:54:01 +0000115struct delayed_work {
116 struct work_struct work;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700117 struct timer_list timer;
Lai Jiangshan60c057b2013-02-06 18:04:53 -0800118
119 /* target workqueue and CPU ->timer uses to queue ->work */
120 struct workqueue_struct *wq;
Tejun Heo12650572012-08-08 09:38:42 -0700121 int cpu;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700122};
123
Tejun Heo05f0fe62018-03-14 12:45:13 -0700124struct rcu_work {
125 struct work_struct work;
126 struct rcu_head rcu;
127
128 /* target workqueue ->rcu uses to queue ->work */
129 struct workqueue_struct *wq;
130};
131
Silvio Fricke42412c32016-10-28 10:14:09 +0200132/**
133 * struct workqueue_attrs - A struct for workqueue attributes.
Tejun Heod55262c2013-04-01 11:23:38 -0700134 *
Silvio Fricke42412c32016-10-28 10:14:09 +0200135 * This can be used to change attributes of an unbound workqueue.
Tejun Heo7a4e3442013-03-12 11:30:00 -0700136 */
137struct workqueue_attrs {
Silvio Fricke42412c32016-10-28 10:14:09 +0200138 /**
139 * @nice: nice level
140 */
141 int nice;
142
143 /**
144 * @cpumask: allowed CPUs
145 */
146 cpumask_var_t cpumask;
147
148 /**
149 * @no_numa: disable NUMA affinity
150 *
151 * Unlike other fields, ``no_numa`` isn't a property of a worker_pool. It
152 * only modifies how :c:func:`apply_workqueue_attrs` select pools and thus
153 * doesn't participate in pool hash calculations or equality comparisons.
154 */
155 bool no_numa;
Tejun Heo7a4e3442013-03-12 11:30:00 -0700156};
157
Jean Delvarebf6aede2009-04-02 16:56:54 -0700158static inline struct delayed_work *to_delayed_work(struct work_struct *work)
159{
160 return container_of(work, struct delayed_work, work);
161}
162
Tejun Heo05f0fe62018-03-14 12:45:13 -0700163static inline struct rcu_work *to_rcu_work(struct work_struct *work)
164{
165 return container_of(work, struct rcu_work, work);
166}
167
James Bottomley1fa44ec2006-02-23 12:43:43 -0600168struct execute_work {
169 struct work_struct work;
170};
171
Johannes Berg4e6045f2007-10-18 23:39:55 -0700172#ifdef CONFIG_LOCKDEP
173/*
174 * NB: because we have to copy the lockdep_map, setting _key
175 * here is required, otherwise it could get initialised to the
176 * copy of the lockdep_map!
177 */
178#define __WORK_INIT_LOCKDEP_MAP(n, k) \
179 .lockdep_map = STATIC_LOCKDEP_MAP_INIT(n, k),
180#else
181#define __WORK_INIT_LOCKDEP_MAP(n, k)
182#endif
183
Tejun Heoee64e7f2012-08-21 13:18:23 -0700184#define __WORK_INITIALIZER(n, f) { \
185 .data = WORK_DATA_STATIC_INIT(), \
186 .entry = { &(n).entry, &(n).entry }, \
187 .func = (f), \
188 __WORK_INIT_LOCKDEP_MAP(#n, &(n)) \
David Howells65f27f32006-11-22 14:55:48 +0000189 }
190
Tejun Heof991b312012-08-21 13:18:23 -0700191#define __DELAYED_WORK_INITIALIZER(n, f, tflags) { \
Tejun Heoee64e7f2012-08-21 13:18:23 -0700192 .work = __WORK_INITIALIZER((n).work, (f)), \
Kees Cook841b86f2017-10-23 09:40:42 +0200193 .timer = __TIMER_INITIALIZER(delayed_work_timer_fn,\
Tejun Heoe0aecdd2012-08-21 13:18:24 -0700194 (tflags) | TIMER_IRQSAFE), \
Phil Carmodydd6414b2010-10-20 15:57:33 -0700195 }
196
Tejun Heoee64e7f2012-08-21 13:18:23 -0700197#define DECLARE_WORK(n, f) \
David Howells65f27f32006-11-22 14:55:48 +0000198 struct work_struct n = __WORK_INITIALIZER(n, f)
199
Tejun Heoee64e7f2012-08-21 13:18:23 -0700200#define DECLARE_DELAYED_WORK(n, f) \
Tejun Heof991b312012-08-21 13:18:23 -0700201 struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, 0)
David Howells65f27f32006-11-22 14:55:48 +0000202
Tejun Heo203b42f2012-08-21 13:18:23 -0700203#define DECLARE_DEFERRABLE_WORK(n, f) \
Tejun Heof991b312012-08-21 13:18:23 -0700204 struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, TIMER_DEFERRABLE)
Phil Carmodydd6414b2010-10-20 15:57:33 -0700205
Thomas Gleixnerdc186ad2009-11-16 01:09:48 +0900206#ifdef CONFIG_DEBUG_OBJECTS_WORK
207extern void __init_work(struct work_struct *work, int onstack);
208extern void destroy_work_on_stack(struct work_struct *work);
Thomas Gleixnerea2e64f2014-03-23 14:20:44 +0000209extern void destroy_delayed_work_on_stack(struct delayed_work *work);
Tejun Heo4690c4a2010-06-29 10:07:10 +0200210static inline unsigned int work_static(struct work_struct *work)
211{
Tejun Heo22df02b2010-06-29 10:07:10 +0200212 return *work_data_bits(work) & WORK_STRUCT_STATIC;
Tejun Heo4690c4a2010-06-29 10:07:10 +0200213}
Thomas Gleixnerdc186ad2009-11-16 01:09:48 +0900214#else
215static inline void __init_work(struct work_struct *work, int onstack) { }
216static inline void destroy_work_on_stack(struct work_struct *work) { }
Thomas Gleixnerea2e64f2014-03-23 14:20:44 +0000217static inline void destroy_delayed_work_on_stack(struct delayed_work *work) { }
Tejun Heo4690c4a2010-06-29 10:07:10 +0200218static inline unsigned int work_static(struct work_struct *work) { return 0; }
Thomas Gleixnerdc186ad2009-11-16 01:09:48 +0900219#endif
220
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221/*
David Howells52bad642006-11-22 14:54:01 +0000222 * initialize all of a work item in one go
Linus Torvaldsa08727b2006-12-16 09:53:50 -0800223 *
Dmitri Vorobievb9049df2009-06-23 12:09:29 +0200224 * NOTE! No point in using "atomic_long_set()": using a direct
Linus Torvaldsa08727b2006-12-16 09:53:50 -0800225 * assignment of the work data initializer allows the compiler
226 * to generate better code.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227 */
Johannes Berg4e6045f2007-10-18 23:39:55 -0700228#ifdef CONFIG_LOCKDEP
Thomas Gleixnerdc186ad2009-11-16 01:09:48 +0900229#define __INIT_WORK(_work, _func, _onstack) \
Johannes Berg4e6045f2007-10-18 23:39:55 -0700230 do { \
231 static struct lock_class_key __key; \
232 \
Thomas Gleixnerdc186ad2009-11-16 01:09:48 +0900233 __init_work((_work), _onstack); \
Johannes Berg4e6045f2007-10-18 23:39:55 -0700234 (_work)->data = (atomic_long_t) WORK_DATA_INIT(); \
Byungchul Parkfd1a5b02017-10-25 17:56:04 +0900235 lockdep_init_map(&(_work)->lockdep_map, "(work_completion)"#_work, &__key, 0); \
Johannes Berg4e6045f2007-10-18 23:39:55 -0700236 INIT_LIST_HEAD(&(_work)->entry); \
Tejun Heof073f922014-03-07 10:24:50 -0500237 (_work)->func = (_func); \
Johannes Berg4e6045f2007-10-18 23:39:55 -0700238 } while (0)
239#else
Thomas Gleixnerdc186ad2009-11-16 01:09:48 +0900240#define __INIT_WORK(_work, _func, _onstack) \
David Howells65f27f32006-11-22 14:55:48 +0000241 do { \
Thomas Gleixnerdc186ad2009-11-16 01:09:48 +0900242 __init_work((_work), _onstack); \
Oleg Nesterov23b2e592007-05-09 02:34:19 -0700243 (_work)->data = (atomic_long_t) WORK_DATA_INIT(); \
David Howells65f27f32006-11-22 14:55:48 +0000244 INIT_LIST_HEAD(&(_work)->entry); \
Tejun Heof073f922014-03-07 10:24:50 -0500245 (_work)->func = (_func); \
David Howells65f27f32006-11-22 14:55:48 +0000246 } while (0)
Johannes Berg4e6045f2007-10-18 23:39:55 -0700247#endif
David Howells65f27f32006-11-22 14:55:48 +0000248
Tejun Heoee64e7f2012-08-21 13:18:23 -0700249#define INIT_WORK(_work, _func) \
Valentin Rothberg9da7dae2015-01-06 17:29:29 +0100250 __INIT_WORK((_work), (_func), 0)
Thomas Gleixnerdc186ad2009-11-16 01:09:48 +0900251
Tejun Heoee64e7f2012-08-21 13:18:23 -0700252#define INIT_WORK_ONSTACK(_work, _func) \
Valentin Rothberg9da7dae2015-01-06 17:29:29 +0100253 __INIT_WORK((_work), (_func), 1)
Thomas Gleixnerdc186ad2009-11-16 01:09:48 +0900254
Tejun Heof991b312012-08-21 13:18:23 -0700255#define __INIT_DELAYED_WORK(_work, _func, _tflags) \
Tejun Heoee64e7f2012-08-21 13:18:23 -0700256 do { \
257 INIT_WORK(&(_work)->work, (_func)); \
Kees Cook919b2502017-10-22 18:48:43 -0700258 __init_timer(&(_work)->timer, \
259 delayed_work_timer_fn, \
260 (_tflags) | TIMER_IRQSAFE); \
David Howells65f27f32006-11-22 14:55:48 +0000261 } while (0)
262
Tejun Heof991b312012-08-21 13:18:23 -0700263#define __INIT_DELAYED_WORK_ONSTACK(_work, _func, _tflags) \
Tejun Heoee64e7f2012-08-21 13:18:23 -0700264 do { \
265 INIT_WORK_ONSTACK(&(_work)->work, (_func)); \
Kees Cook919b2502017-10-22 18:48:43 -0700266 __init_timer_on_stack(&(_work)->timer, \
267 delayed_work_timer_fn, \
268 (_tflags) | TIMER_IRQSAFE); \
Peter Zijlstra6d612b02009-01-12 12:52:23 +0100269 } while (0)
270
Tejun Heof991b312012-08-21 13:18:23 -0700271#define INIT_DELAYED_WORK(_work, _func) \
272 __INIT_DELAYED_WORK(_work, _func, 0)
273
274#define INIT_DELAYED_WORK_ONSTACK(_work, _func) \
275 __INIT_DELAYED_WORK_ONSTACK(_work, _func, 0)
276
Tejun Heo203b42f2012-08-21 13:18:23 -0700277#define INIT_DEFERRABLE_WORK(_work, _func) \
Tejun Heof991b312012-08-21 13:18:23 -0700278 __INIT_DELAYED_WORK(_work, _func, TIMER_DEFERRABLE)
279
280#define INIT_DEFERRABLE_WORK_ONSTACK(_work, _func) \
281 __INIT_DELAYED_WORK_ONSTACK(_work, _func, TIMER_DEFERRABLE)
Venki Pallipadi28287032007-05-08 00:27:47 -0700282
Tejun Heo05f0fe62018-03-14 12:45:13 -0700283#define INIT_RCU_WORK(_work, _func) \
284 INIT_WORK(&(_work)->work, (_func))
285
286#define INIT_RCU_WORK_ONSTACK(_work, _func) \
287 INIT_WORK_ONSTACK(&(_work)->work, (_func))
288
David Howells365970a2006-11-22 14:54:49 +0000289/**
290 * work_pending - Find out whether a work item is currently pending
291 * @work: The work item in question
292 */
293#define work_pending(work) \
Tejun Heo22df02b2010-06-29 10:07:10 +0200294 test_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))
David Howells365970a2006-11-22 14:54:49 +0000295
296/**
297 * delayed_work_pending - Find out whether a delayable work item is currently
298 * pending
Jonathan Corbet355c06632015-08-13 17:52:02 -0600299 * @w: The work item in question
David Howells365970a2006-11-22 14:54:49 +0000300 */
Linus Torvalds02218722006-12-15 14:13:51 -0800301#define delayed_work_pending(w) \
302 work_pending(&(w)->work)
David Howells365970a2006-11-22 14:54:49 +0000303
Tejun Heoc54fce62010-09-10 16:51:36 +0200304/*
305 * Workqueue flags and constants. For details, please refer to
Silvio Fricke42412c32016-10-28 10:14:09 +0200306 * Documentation/core-api/workqueue.rst.
Tejun Heoc54fce62010-09-10 16:51:36 +0200307 */
Tejun Heo97e37d72010-06-29 10:07:10 +0200308enum {
Tejun Heoc7fc77f2010-07-02 10:03:51 +0200309 WQ_UNBOUND = 1 << 1, /* not bound to any cpu */
Tejun Heo58a69cb2011-02-16 09:25:31 +0100310 WQ_FREEZABLE = 1 << 2, /* freeze during suspend */
Tejun Heo6370a6a2010-10-11 15:12:27 +0200311 WQ_MEM_RECLAIM = 1 << 3, /* may be used for memory reclaim */
Tejun Heo649027d2010-06-29 10:07:14 +0200312 WQ_HIGHPRI = 1 << 4, /* high priority */
Geert Uytterhoeven41f50092014-03-24 21:37:02 +0100313 WQ_CPU_INTENSIVE = 1 << 5, /* cpu intensive workqueue */
Tejun Heo226223a2013-03-12 11:30:05 -0700314 WQ_SYSFS = 1 << 6, /* visible in sysfs, see wq_sysfs_register() */
Tejun Heob71ab8c2010-06-29 10:07:14 +0200315
Viresh Kumarcee22a12013-04-08 16:45:40 +0530316 /*
317 * Per-cpu workqueues are generally preferred because they tend to
318 * show better performance thanks to cache locality. Per-cpu
319 * workqueues exclude the scheduler from choosing the CPU to
320 * execute the worker threads, which has an unfortunate side effect
321 * of increasing power consumption.
322 *
323 * The scheduler considers a CPU idle if it doesn't have any task
324 * to execute and tries to keep idle cores idle to conserve power;
325 * however, for example, a per-cpu work item scheduled from an
326 * interrupt handler on an idle CPU will force the scheduler to
327 * excute the work item on that CPU breaking the idleness, which in
328 * turn may lead to more scheduling choices which are sub-optimal
329 * in terms of power consumption.
330 *
331 * Workqueues marked with WQ_POWER_EFFICIENT are per-cpu by default
332 * but become unbound if workqueue.power_efficient kernel param is
333 * specified. Per-cpu workqueues which are identified to
334 * contribute significantly to power-consumption are identified and
335 * marked with this flag and enabling the power_efficient mode
336 * leads to noticeable power saving at the cost of small
337 * performance disadvantage.
338 *
339 * http://thread.gmane.org/gmane.linux.kernel/1480396
340 */
341 WQ_POWER_EFFICIENT = 1 << 7,
342
Tejun Heo618b01e2013-03-12 11:30:04 -0700343 __WQ_DRAINING = 1 << 16, /* internal: workqueue is draining */
Tejun Heo8719dce2013-03-12 11:30:04 -0700344 __WQ_ORDERED = 1 << 17, /* internal: workqueue is ordered */
Tejun Heo23d11a52016-01-29 05:59:46 -0500345 __WQ_LEGACY = 1 << 18, /* internal: create*_workqueue() */
Ben Hutchingsfbf1c412017-09-03 01:18:41 +0100346 __WQ_ORDERED_EXPLICIT = 1 << 19, /* internal: alloc_ordered_workqueue() */
Tejun Heoe41e7042010-08-24 14:22:47 +0200347
Tejun Heob71ab8c2010-06-29 10:07:14 +0200348 WQ_MAX_ACTIVE = 512, /* I like 512, better ideas? */
Tejun Heof3421792010-07-02 10:03:51 +0200349 WQ_MAX_UNBOUND_PER_CPU = 4, /* 4 * #cpus for unbound wq */
Tejun Heob71ab8c2010-06-29 10:07:14 +0200350 WQ_DFL_ACTIVE = WQ_MAX_ACTIVE / 2,
Tejun Heo97e37d72010-06-29 10:07:10 +0200351};
David Howells52bad642006-11-22 14:54:01 +0000352
Tejun Heof3421792010-07-02 10:03:51 +0200353/* unbound wq's aren't per-cpu, scale max_active according to #cpus */
354#define WQ_UNBOUND_MAX_ACTIVE \
355 max_t(int, WQ_MAX_ACTIVE, num_possible_cpus() * WQ_MAX_UNBOUND_PER_CPU)
356
Tejun Heod320c032010-06-29 10:07:14 +0200357/*
358 * System-wide workqueues which are always present.
359 *
360 * system_wq is the one used by schedule[_delayed]_work[_on]().
361 * Multi-CPU multi-threaded. There are users which expect relatively
362 * short queue flush time. Don't queue works which can run for too
363 * long.
364 *
Lai Jiangshan73e43542014-05-22 16:42:41 +0800365 * system_highpri_wq is similar to system_wq but for work items which
366 * require WQ_HIGHPRI.
367 *
Tejun Heod320c032010-06-29 10:07:14 +0200368 * system_long_wq is similar to system_wq but may host long running
369 * works. Queue flushing might take relatively long.
370 *
Tejun Heof3421792010-07-02 10:03:51 +0200371 * system_unbound_wq is unbound workqueue. Workers are not bound to
372 * any specific CPU, not concurrency managed, and all queued works are
373 * executed immediately as long as max_active limit is not reached and
374 * resources are available.
Tejun Heo4149efb2011-02-08 10:39:03 +0100375 *
Tejun Heo24d51ad2011-02-21 09:52:50 +0100376 * system_freezable_wq is equivalent to system_wq except that it's
377 * freezable.
Viresh Kumar06681062013-04-24 17:12:54 +0530378 *
379 * *_power_efficient_wq are inclined towards saving power and converted
380 * into WQ_UNBOUND variants if 'wq_power_efficient' is enabled; otherwise,
381 * they are same as their non-power-efficient counterparts - e.g.
382 * system_power_efficient_wq is identical to system_wq if
383 * 'wq_power_efficient' is disabled. See WQ_POWER_EFFICIENT for more info.
Tejun Heod320c032010-06-29 10:07:14 +0200384 */
385extern struct workqueue_struct *system_wq;
Lai Jiangshan73e43542014-05-22 16:42:41 +0800386extern struct workqueue_struct *system_highpri_wq;
Tejun Heod320c032010-06-29 10:07:14 +0200387extern struct workqueue_struct *system_long_wq;
Tejun Heof3421792010-07-02 10:03:51 +0200388extern struct workqueue_struct *system_unbound_wq;
Tejun Heo24d51ad2011-02-21 09:52:50 +0100389extern struct workqueue_struct *system_freezable_wq;
Viresh Kumar06681062013-04-24 17:12:54 +0530390extern struct workqueue_struct *system_power_efficient_wq;
391extern struct workqueue_struct *system_freezable_power_efficient_wq;
Tejun Heoae930e02012-08-20 14:51:23 -0700392
Tejun Heob196be82012-01-10 15:11:35 -0800393/**
394 * alloc_workqueue - allocate a workqueue
395 * @fmt: printf format for the name of the workqueue
396 * @flags: WQ_* flags
397 * @max_active: max in-flight work items, 0 for default
Bart Van Assche669de8b2019-02-14 15:00:54 -0800398 * remaining args: args for @fmt
Tejun Heob196be82012-01-10 15:11:35 -0800399 *
400 * Allocate a workqueue with the specified parameters. For detailed
Silvio Fricke42412c32016-10-28 10:14:09 +0200401 * information on WQ_* flags, please refer to
402 * Documentation/core-api/workqueue.rst.
Tejun Heob196be82012-01-10 15:11:35 -0800403 *
Tejun Heob196be82012-01-10 15:11:35 -0800404 * RETURNS:
405 * Pointer to the allocated workqueue on success, %NULL on failure.
406 */
Bart Van Assche669de8b2019-02-14 15:00:54 -0800407struct workqueue_struct *alloc_workqueue(const char *fmt,
408 unsigned int flags,
409 int max_active, ...);
Johannes Berg4e6045f2007-10-18 23:39:55 -0700410
Tejun Heo81dcaf62010-09-16 10:17:35 +0200411/**
412 * alloc_ordered_workqueue - allocate an ordered workqueue
Tejun Heob196be82012-01-10 15:11:35 -0800413 * @fmt: printf format for the name of the workqueue
Tejun Heo58a69cb2011-02-16 09:25:31 +0100414 * @flags: WQ_* flags (only WQ_FREEZABLE and WQ_MEM_RECLAIM are meaningful)
Jonathan Corbet355c06632015-08-13 17:52:02 -0600415 * @args...: args for @fmt
Tejun Heo81dcaf62010-09-16 10:17:35 +0200416 *
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.
420 *
421 * RETURNS:
422 * Pointer to the allocated workqueue on success, %NULL on failure.
423 */
Tejun Heoee64e7f2012-08-21 13:18:23 -0700424#define alloc_ordered_workqueue(fmt, flags, args...) \
Tejun Heo0a94efb2017-07-23 08:36:15 -0400425 alloc_workqueue(fmt, WQ_UNBOUND | __WQ_ORDERED | \
426 __WQ_ORDERED_EXPLICIT | (flags), 1, ##args)
Tejun Heo81dcaf62010-09-16 10:17:35 +0200427
Tejun Heoee64e7f2012-08-21 13:18:23 -0700428#define create_workqueue(name) \
Tejun Heo23d11a52016-01-29 05:59:46 -0500429 alloc_workqueue("%s", __WQ_LEGACY | WQ_MEM_RECLAIM, 1, (name))
Tejun Heoee64e7f2012-08-21 13:18:23 -0700430#define create_freezable_workqueue(name) \
Tejun Heo23d11a52016-01-29 05:59:46 -0500431 alloc_workqueue("%s", __WQ_LEGACY | WQ_FREEZABLE | WQ_UNBOUND | \
432 WQ_MEM_RECLAIM, 1, (name))
Tejun Heoee64e7f2012-08-21 13:18:23 -0700433#define create_singlethread_workqueue(name) \
Tejun Heo23d11a52016-01-29 05:59:46 -0500434 alloc_ordered_workqueue("%s", __WQ_LEGACY | WQ_MEM_RECLAIM, name)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700435
436extern void destroy_workqueue(struct workqueue_struct *wq);
437
Tejun Heo7a4e3442013-03-12 11:30:00 -0700438struct workqueue_attrs *alloc_workqueue_attrs(gfp_t gfp_mask);
439void free_workqueue_attrs(struct workqueue_attrs *attrs);
Tejun Heo9e8cd2f2013-03-12 11:30:04 -0700440int apply_workqueue_attrs(struct workqueue_struct *wq,
441 const struct workqueue_attrs *attrs);
Lai Jiangshan042f7df2015-04-30 17:16:12 +0800442int workqueue_set_unbound_cpumask(cpumask_var_t cpumask);
Tejun Heo7a4e3442013-03-12 11:30:00 -0700443
Tejun Heod4283e92012-08-03 10:30:44 -0700444extern bool queue_work_on(int cpu, struct workqueue_struct *wq,
Zhang Ruic1a220e2008-07-23 21:28:39 -0700445 struct work_struct *work);
Tejun Heod4283e92012-08-03 10:30:44 -0700446extern bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
Oleg Nesterov28e53bd2007-05-09 02:34:22 -0700447 struct delayed_work *work, unsigned long delay);
Tejun Heo8376fe22012-08-03 10:30:47 -0700448extern bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq,
449 struct delayed_work *dwork, unsigned long delay);
Tejun Heo05f0fe62018-03-14 12:45:13 -0700450extern bool queue_rcu_work(struct workqueue_struct *wq, struct rcu_work *rwork);
Oleg Nesterov28e53bd2007-05-09 02:34:22 -0700451
Harvey Harrisonb3c97522008-02-13 15:03:15 -0800452extern void flush_workqueue(struct workqueue_struct *wq);
Tejun Heo9c5a2ba2011-04-05 18:01:44 +0200453extern void drain_workqueue(struct workqueue_struct *wq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700454
David Howells65f27f32006-11-22 14:55:48 +0000455extern int schedule_on_each_cpu(work_func_t func);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700456
David Howells65f27f32006-11-22 14:55:48 +0000457int execute_in_process_context(work_func_t fn, struct execute_work *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700458
Tejun Heo401a8d02010-09-16 10:36:00 +0200459extern bool flush_work(struct work_struct *work);
460extern bool cancel_work_sync(struct work_struct *work);
461
462extern bool flush_delayed_work(struct delayed_work *dwork);
Tejun Heo57b30ae2012-08-21 13:18:24 -0700463extern bool cancel_delayed_work(struct delayed_work *dwork);
Tejun Heo401a8d02010-09-16 10:36:00 +0200464extern bool cancel_delayed_work_sync(struct delayed_work *dwork);
Oleg Nesterov28e53bd2007-05-09 02:34:22 -0700465
Tejun Heo05f0fe62018-03-14 12:45:13 -0700466extern bool flush_rcu_work(struct rcu_work *rwork);
467
Tejun Heodcd989c2010-06-29 10:07:14 +0200468extern void workqueue_set_max_active(struct workqueue_struct *wq,
469 int max_active);
Lukas Wunner27d4ee02018-02-11 10:38:28 +0100470extern struct work_struct *current_work(void);
Tejun Heoe62676162013-03-12 17:41:37 -0700471extern bool current_is_workqueue_rescuer(void);
Tejun Heod84ff052013-03-12 11:29:59 -0700472extern bool workqueue_congested(int cpu, struct workqueue_struct *wq);
Tejun Heodcd989c2010-06-29 10:07:14 +0200473extern unsigned int work_busy(struct work_struct *work);
Tejun Heo3d1cb202013-04-30 15:27:22 -0700474extern __printf(1, 2) void set_worker_desc(const char *fmt, ...);
475extern void print_worker_info(const char *log_lvl, struct task_struct *task);
Tejun Heo3494fc32015-03-09 09:22:28 -0400476extern void show_workqueue_state(void);
Tejun Heo6b598082018-05-18 08:47:13 -0700477extern void wq_worker_comm(char *buf, size_t size, struct task_struct *task);
Tejun Heodcd989c2010-06-29 10:07:14 +0200478
Tejun Heo8425e3d52013-03-13 16:51:36 -0700479/**
480 * queue_work - queue work on a workqueue
481 * @wq: workqueue to use
482 * @work: work to queue
483 *
484 * Returns %false if @work was already on a queue, %true otherwise.
485 *
486 * We queue the work to the CPU on which it was submitted, but if the CPU dies
487 * it can be processed by another CPU.
488 */
489static inline bool queue_work(struct workqueue_struct *wq,
490 struct work_struct *work)
491{
492 return queue_work_on(WORK_CPU_UNBOUND, wq, work);
493}
494
495/**
496 * queue_delayed_work - queue work on a workqueue after delay
497 * @wq: workqueue to use
498 * @dwork: delayable work to queue
499 * @delay: number of jiffies to wait before queueing
500 *
501 * Equivalent to queue_delayed_work_on() but tries to use the local CPU.
502 */
503static inline bool queue_delayed_work(struct workqueue_struct *wq,
504 struct delayed_work *dwork,
505 unsigned long delay)
506{
507 return queue_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay);
508}
509
510/**
511 * mod_delayed_work - modify delay of or queue a delayed work
512 * @wq: workqueue to use
513 * @dwork: work to queue
514 * @delay: number of jiffies to wait before queueing
515 *
516 * mod_delayed_work_on() on local CPU.
517 */
518static inline bool mod_delayed_work(struct workqueue_struct *wq,
519 struct delayed_work *dwork,
520 unsigned long delay)
521{
522 return mod_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay);
523}
524
525/**
526 * schedule_work_on - put work task on a specific cpu
527 * @cpu: cpu to put the work task on
528 * @work: job to be done
529 *
530 * This puts a job on a specific cpu
531 */
532static inline bool schedule_work_on(int cpu, struct work_struct *work)
533{
534 return queue_work_on(cpu, system_wq, work);
535}
536
537/**
538 * schedule_work - put work task in global workqueue
539 * @work: job to be done
540 *
541 * Returns %false if @work was already on the kernel-global workqueue and
542 * %true otherwise.
543 *
544 * This puts a job in the kernel-global workqueue if it was not already
545 * queued and leaves it in the same position on the kernel-global
546 * workqueue otherwise.
547 */
548static inline bool schedule_work(struct work_struct *work)
549{
550 return queue_work(system_wq, work);
551}
552
553/**
Lai Jiangshan37b1ef32015-05-20 14:41:19 +0800554 * flush_scheduled_work - ensure that any scheduled work has run to completion.
555 *
556 * Forces execution of the kernel-global workqueue and blocks until its
557 * completion.
558 *
559 * Think twice before calling this function! It's very easy to get into
560 * trouble if you don't take great care. Either of the following situations
561 * will lead to deadlock:
562 *
563 * One of the work items currently on the workqueue needs to acquire
564 * a lock held by your code or its caller.
565 *
566 * Your code is running in the context of a work routine.
567 *
568 * They will be detected by lockdep when they occur, but the first might not
569 * occur very often. It depends on what work items are on the workqueue and
570 * what locks they need, which you have no control over.
571 *
572 * In most situations flushing the entire workqueue is overkill; you merely
573 * need to know that a particular work item isn't queued and isn't running.
574 * In such cases you should use cancel_delayed_work_sync() or
575 * cancel_work_sync() instead.
576 */
577static inline void flush_scheduled_work(void)
578{
579 flush_workqueue(system_wq);
580}
581
582/**
Tejun Heo8425e3d52013-03-13 16:51:36 -0700583 * schedule_delayed_work_on - queue work in global workqueue on CPU after delay
584 * @cpu: cpu to use
585 * @dwork: job to be done
586 * @delay: number of jiffies to wait
587 *
588 * After waiting for a given time this puts a job in the kernel-global
589 * workqueue on the specified CPU.
590 */
591static inline bool schedule_delayed_work_on(int cpu, struct delayed_work *dwork,
592 unsigned long delay)
593{
594 return queue_delayed_work_on(cpu, system_wq, dwork, delay);
595}
596
597/**
598 * schedule_delayed_work - put work task in global workqueue after delay
599 * @dwork: job to be done
600 * @delay: number of jiffies to wait or 0 for immediate execution
601 *
602 * After waiting for a given time this puts a job in the kernel-global
603 * workqueue.
604 */
605static inline bool schedule_delayed_work(struct delayed_work *dwork,
606 unsigned long delay)
607{
608 return queue_delayed_work(system_wq, dwork, delay);
609}
610
Rusty Russell2d3854a2008-11-05 13:39:10 +1100611#ifndef CONFIG_SMP
Tejun Heod84ff052013-03-12 11:29:59 -0700612static inline long work_on_cpu(int cpu, long (*fn)(void *), void *arg)
Rusty Russell2d3854a2008-11-05 13:39:10 +1100613{
614 return fn(arg);
615}
Thomas Gleixner0e8d6a92017-04-12 22:07:28 +0200616static inline long work_on_cpu_safe(int cpu, long (*fn)(void *), void *arg)
617{
618 return fn(arg);
619}
Rusty Russell2d3854a2008-11-05 13:39:10 +1100620#else
Tejun Heod84ff052013-03-12 11:29:59 -0700621long work_on_cpu(int cpu, long (*fn)(void *), void *arg);
Thomas Gleixner0e8d6a92017-04-12 22:07:28 +0200622long work_on_cpu_safe(int cpu, long (*fn)(void *), void *arg);
Rusty Russell2d3854a2008-11-05 13:39:10 +1100623#endif /* CONFIG_SMP */
Paul E. McKenneya25909a2010-05-13 12:32:28 -0700624
Tejun Heoa0a1a5f2010-06-29 10:07:12 +0200625#ifdef CONFIG_FREEZER
626extern void freeze_workqueues_begin(void);
627extern bool freeze_workqueues_busy(void);
628extern void thaw_workqueues(void);
629#endif /* CONFIG_FREEZER */
630
Tejun Heo226223a2013-03-12 11:30:05 -0700631#ifdef CONFIG_SYSFS
632int workqueue_sysfs_register(struct workqueue_struct *wq);
633#else /* CONFIG_SYSFS */
634static inline int workqueue_sysfs_register(struct workqueue_struct *wq)
635{ return 0; }
636#endif /* CONFIG_SYSFS */
637
Tejun Heo82607adc2015-12-08 11:28:04 -0500638#ifdef CONFIG_WQ_WATCHDOG
639void wq_watchdog_touch(int cpu);
640#else /* CONFIG_WQ_WATCHDOG */
641static inline void wq_watchdog_touch(int cpu) { }
642#endif /* CONFIG_WQ_WATCHDOG */
643
Thomas Gleixner7ee681b2016-07-13 17:16:29 +0000644#ifdef CONFIG_SMP
645int workqueue_prepare_cpu(unsigned int cpu);
646int workqueue_online_cpu(unsigned int cpu);
647int workqueue_offline_cpu(unsigned int cpu);
648#endif
649
Tejun Heo3347fa02016-09-16 15:49:32 -0400650int __init workqueue_init_early(void);
651int __init workqueue_init(void);
652
Linus Torvalds1da177e2005-04-16 15:20:36 -0700653#endif