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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
Tejun Heoc54fce62010-09-10 16:51:36 +02002 * kernel/workqueue.c - generic async execution with shared worker pool
Linus Torvalds1da177e2005-04-16 15:20:36 -07003 *
Tejun Heoc54fce62010-09-10 16:51:36 +02004 * Copyright (C) 2002 Ingo Molnar
Linus Torvalds1da177e2005-04-16 15:20:36 -07005 *
Tejun Heoc54fce62010-09-10 16:51:36 +02006 * Derived from the taskqueue/keventd code by:
7 * David Woodhouse <dwmw2@infradead.org>
8 * Andrew Morton
9 * Kai Petzke <wpp@marie.physik.tu-berlin.de>
10 * Theodore Ts'o <tytso@mit.edu>
Christoph Lameter89ada672005-10-30 15:01:59 -080011 *
Christoph Lametercde53532008-07-04 09:59:22 -070012 * Made to use alloc_percpu by Christoph Lameter.
Tejun Heoc54fce62010-09-10 16:51:36 +020013 *
14 * Copyright (C) 2010 SUSE Linux Products GmbH
15 * Copyright (C) 2010 Tejun Heo <tj@kernel.org>
16 *
17 * This is the generic async execution mechanism. Work items as are
18 * executed in process context. The worker pool is shared and
Libinb11895c2013-08-21 08:50:39 +080019 * automatically managed. There are two worker pools for each CPU (one for
20 * normal work items and the other for high priority ones) and some extra
21 * pools for workqueues which are not bound to any specific CPU - the
22 * number of these backing pools is dynamic.
Tejun Heoc54fce62010-09-10 16:51:36 +020023 *
24 * Please read Documentation/workqueue.txt for details.
Linus Torvalds1da177e2005-04-16 15:20:36 -070025 */
26
Paul Gortmaker9984de12011-05-23 14:51:41 -040027#include <linux/export.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070028#include <linux/kernel.h>
29#include <linux/sched.h>
30#include <linux/init.h>
31#include <linux/signal.h>
32#include <linux/completion.h>
33#include <linux/workqueue.h>
34#include <linux/slab.h>
35#include <linux/cpu.h>
36#include <linux/notifier.h>
37#include <linux/kthread.h>
James Bottomley1fa44ec2006-02-23 12:43:43 -060038#include <linux/hardirq.h>
Christoph Lameter46934022006-10-11 01:21:26 -070039#include <linux/mempolicy.h>
Rafael J. Wysocki341a5952006-12-06 20:34:49 -080040#include <linux/freezer.h>
Peter Zijlstrad5abe662006-12-06 20:37:26 -080041#include <linux/kallsyms.h>
42#include <linux/debug_locks.h>
Johannes Berg4e6045f2007-10-18 23:39:55 -070043#include <linux/lockdep.h>
Tejun Heoc34056a2010-06-29 10:07:11 +020044#include <linux/idr.h>
Tejun Heo29c91e92013-03-12 11:30:03 -070045#include <linux/jhash.h>
Sasha Levin42f85702012-12-17 10:01:23 -050046#include <linux/hashtable.h>
Tejun Heo76af4d92013-03-12 11:30:00 -070047#include <linux/rculist.h>
Tejun Heobce90382013-04-01 11:23:32 -070048#include <linux/nodemask.h>
Tejun Heo4c16bd32013-04-01 11:23:36 -070049#include <linux/moduleparam.h>
Tejun Heo3d1cb202013-04-30 15:27:22 -070050#include <linux/uaccess.h>
Tejun Heoe22bee72010-06-29 10:07:14 +020051
Tejun Heoea138442013-01-18 14:05:55 -080052#include "workqueue_internal.h"
Linus Torvalds1da177e2005-04-16 15:20:36 -070053
Tejun Heoc8e55f32010-06-29 10:07:12 +020054enum {
Tejun Heobc2ae0f2012-07-17 12:39:27 -070055 /*
Tejun Heo24647572013-01-24 11:01:33 -080056 * worker_pool flags
Tejun Heobc2ae0f2012-07-17 12:39:27 -070057 *
Tejun Heo24647572013-01-24 11:01:33 -080058 * A bound pool is either associated or disassociated with its CPU.
Tejun Heobc2ae0f2012-07-17 12:39:27 -070059 * While associated (!DISASSOCIATED), all workers are bound to the
60 * CPU and none has %WORKER_UNBOUND set and concurrency management
61 * is in effect.
62 *
63 * While DISASSOCIATED, the cpu may be offline and all workers have
64 * %WORKER_UNBOUND set and concurrency management disabled, and may
Tejun Heo24647572013-01-24 11:01:33 -080065 * be executing on any CPU. The pool behaves as an unbound one.
Tejun Heobc2ae0f2012-07-17 12:39:27 -070066 *
Tejun Heobc3a1af2013-03-13 19:47:39 -070067 * Note that DISASSOCIATED should be flipped only while holding
68 * manager_mutex to avoid changing binding state while
Tejun Heo24647572013-01-24 11:01:33 -080069 * create_worker() is in progress.
Tejun Heobc2ae0f2012-07-17 12:39:27 -070070 */
Tejun Heo24647572013-01-24 11:01:33 -080071 POOL_DISASSOCIATED = 1 << 2, /* cpu can't serve workers */
Tejun Heo35b6bb62013-01-24 11:01:33 -080072 POOL_FREEZING = 1 << 3, /* freeze in progress */
Tejun Heodb7bccf2010-06-29 10:07:12 +020073
Tejun Heoc8e55f32010-06-29 10:07:12 +020074 /* worker flags */
Tejun Heoc8e55f32010-06-29 10:07:12 +020075 WORKER_DIE = 1 << 1, /* die die die */
76 WORKER_IDLE = 1 << 2, /* is idle */
Tejun Heoe22bee72010-06-29 10:07:14 +020077 WORKER_PREP = 1 << 3, /* preparing to run works */
Tejun Heofb0e7be2010-06-29 10:07:15 +020078 WORKER_CPU_INTENSIVE = 1 << 6, /* cpu intensive */
Tejun Heof3421792010-07-02 10:03:51 +020079 WORKER_UNBOUND = 1 << 7, /* worker is unbound */
Tejun Heoa9ab7752013-03-19 13:45:21 -070080 WORKER_REBOUND = 1 << 8, /* worker was rebound */
Tejun Heoe22bee72010-06-29 10:07:14 +020081
Tejun Heoa9ab7752013-03-19 13:45:21 -070082 WORKER_NOT_RUNNING = WORKER_PREP | WORKER_CPU_INTENSIVE |
83 WORKER_UNBOUND | WORKER_REBOUND,
Tejun Heodb7bccf2010-06-29 10:07:12 +020084
Tejun Heoe34cdddb2013-01-24 11:01:33 -080085 NR_STD_WORKER_POOLS = 2, /* # standard pools per cpu */
Tejun Heo4ce62e92012-07-13 22:16:44 -070086
Tejun Heo29c91e92013-03-12 11:30:03 -070087 UNBOUND_POOL_HASH_ORDER = 6, /* hashed by pool->attrs */
Tejun Heoc8e55f32010-06-29 10:07:12 +020088 BUSY_WORKER_HASH_ORDER = 6, /* 64 pointers */
Tejun Heodb7bccf2010-06-29 10:07:12 +020089
Tejun Heoe22bee72010-06-29 10:07:14 +020090 MAX_IDLE_WORKERS_RATIO = 4, /* 1/4 of busy can be idle */
91 IDLE_WORKER_TIMEOUT = 300 * HZ, /* keep idle ones for 5 mins */
92
Tejun Heo3233cdb2011-02-16 18:10:19 +010093 MAYDAY_INITIAL_TIMEOUT = HZ / 100 >= 2 ? HZ / 100 : 2,
94 /* call for help after 10ms
95 (min two ticks) */
Tejun Heoe22bee72010-06-29 10:07:14 +020096 MAYDAY_INTERVAL = HZ / 10, /* and then every 100ms */
97 CREATE_COOLDOWN = HZ, /* time to breath after fail */
Tejun Heoe22bee72010-06-29 10:07:14 +020098
99 /*
100 * Rescue workers are used only on emergencies and shared by
101 * all cpus. Give -20.
102 */
103 RESCUER_NICE_LEVEL = -20,
Tejun Heo32704762012-07-13 22:16:45 -0700104 HIGHPRI_NICE_LEVEL = -20,
Tejun Heoecf68812013-04-01 11:23:34 -0700105
106 WQ_NAME_LEN = 24,
Tejun Heoc8e55f32010-06-29 10:07:12 +0200107};
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108
109/*
Tejun Heo4690c4a2010-06-29 10:07:10 +0200110 * Structure fields follow one of the following exclusion rules.
111 *
Tejun Heoe41e7042010-08-24 14:22:47 +0200112 * I: Modifiable by initialization/destruction paths and read-only for
113 * everyone else.
Tejun Heo4690c4a2010-06-29 10:07:10 +0200114 *
Tejun Heoe22bee72010-06-29 10:07:14 +0200115 * P: Preemption protected. Disabling preemption is enough and should
116 * only be modified and accessed from the local cpu.
117 *
Tejun Heod565ed62013-01-24 11:01:33 -0800118 * L: pool->lock protected. Access with pool->lock held.
Tejun Heo4690c4a2010-06-29 10:07:10 +0200119 *
Tejun Heod565ed62013-01-24 11:01:33 -0800120 * X: During normal operation, modification requires pool->lock and should
121 * be done only from local cpu. Either disabling preemption on local
122 * cpu or grabbing pool->lock is enough for read access. If
123 * POOL_DISASSOCIATED is set, it's identical to L.
Tejun Heoe22bee72010-06-29 10:07:14 +0200124 *
Lai Jiangshan9625ab12014-05-20 17:46:27 +0800125 * M: pool->manager_mutex protected.
Tejun Heo822d8402013-03-19 13:45:21 -0700126 *
Lai Jiangshan68e13a62013-03-25 16:57:17 -0700127 * PL: wq_pool_mutex protected.
Tejun Heo76af4d92013-03-12 11:30:00 -0700128 *
Lai Jiangshan68e13a62013-03-25 16:57:17 -0700129 * PR: wq_pool_mutex protected for writes. Sched-RCU protected for reads.
Tejun Heo5bcab332013-03-13 19:47:40 -0700130 *
Lai Jiangshan3c25a552013-03-25 16:57:17 -0700131 * WQ: wq->mutex protected.
132 *
Lai Jiangshanb5927602013-03-25 16:57:19 -0700133 * WR: wq->mutex protected for writes. Sched-RCU protected for reads.
Tejun Heo2e109a22013-03-13 19:47:40 -0700134 *
135 * MD: wq_mayday_lock protected.
Tejun Heo4690c4a2010-06-29 10:07:10 +0200136 */
137
Tejun Heo2eaebdb2013-01-18 14:05:55 -0800138/* struct worker is defined in workqueue_internal.h */
Tejun Heoc34056a2010-06-29 10:07:11 +0200139
Tejun Heobd7bdd42012-07-12 14:46:37 -0700140struct worker_pool {
Tejun Heod565ed62013-01-24 11:01:33 -0800141 spinlock_t lock; /* the pool lock */
Tejun Heod84ff052013-03-12 11:29:59 -0700142 int cpu; /* I: the associated cpu */
Tejun Heof3f90ad2013-04-01 11:23:34 -0700143 int node; /* I: the associated node ID */
Tejun Heo9daf9e62013-01-24 11:01:33 -0800144 int id; /* I: pool ID */
Tejun Heo11ebea52012-07-12 14:46:37 -0700145 unsigned int flags; /* X: flags */
Tejun Heobd7bdd42012-07-12 14:46:37 -0700146
147 struct list_head worklist; /* L: list of pending works */
148 int nr_workers; /* L: total number of workers */
Lai Jiangshanea1abd62012-09-18 09:59:22 -0700149
150 /* nr_idle includes the ones off idle_list for rebinding */
Tejun Heobd7bdd42012-07-12 14:46:37 -0700151 int nr_idle; /* L: currently idle ones */
152
153 struct list_head idle_list; /* X: list of idle workers */
154 struct timer_list idle_timer; /* L: worker idle timeout */
155 struct timer_list mayday_timer; /* L: SOS timer for workers */
156
Tejun Heoc5aa87b2013-03-13 16:51:36 -0700157 /* a workers is either on busy_hash or idle_list, or the manager */
Tejun Heoc9e7cf22013-01-24 11:01:33 -0800158 DECLARE_HASHTABLE(busy_hash, BUSY_WORKER_HASH_ORDER);
159 /* L: hash of busy workers */
160
Tejun Heobc3a1af2013-03-13 19:47:39 -0700161 /* see manage_workers() for details on the two manager mutexes */
Tejun Heo34a06bd2013-03-12 11:30:00 -0700162 struct mutex manager_arb; /* manager arbitration */
Tejun Heobc3a1af2013-03-13 19:47:39 -0700163 struct mutex manager_mutex; /* manager exclusion */
Lai Jiangshanda028462014-05-20 17:46:31 +0800164 struct idr worker_idr; /* M: worker IDs */
165 struct list_head workers; /* M: attached workers */
Lai Jiangshan60f5a4b2014-05-20 17:46:29 +0800166 struct completion *detach_completion; /* all workers detached */
Tejun Heoe19e3972013-01-24 11:39:44 -0800167
Tejun Heo7a4e3442013-03-12 11:30:00 -0700168 struct workqueue_attrs *attrs; /* I: worker attributes */
Lai Jiangshan68e13a62013-03-25 16:57:17 -0700169 struct hlist_node hash_node; /* PL: unbound_pool_hash node */
170 int refcnt; /* PL: refcnt for unbound pools */
Tejun Heo7a4e3442013-03-12 11:30:00 -0700171
Tejun Heoe19e3972013-01-24 11:39:44 -0800172 /*
173 * The current concurrency level. As it's likely to be accessed
174 * from other CPUs during try_to_wake_up(), put it in a separate
175 * cacheline.
176 */
177 atomic_t nr_running ____cacheline_aligned_in_smp;
Tejun Heo29c91e92013-03-12 11:30:03 -0700178
179 /*
180 * Destruction of pool is sched-RCU protected to allow dereferences
181 * from get_work_pool().
182 */
183 struct rcu_head rcu;
Tejun Heo8b03ae32010-06-29 10:07:12 +0200184} ____cacheline_aligned_in_smp;
185
186/*
Tejun Heo112202d2013-02-13 19:29:12 -0800187 * The per-pool workqueue. While queued, the lower WORK_STRUCT_FLAG_BITS
188 * of work_struct->data are used for flags and the remaining high bits
189 * point to the pwq; thus, pwqs need to be aligned at two's power of the
190 * number of flag bits.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191 */
Tejun Heo112202d2013-02-13 19:29:12 -0800192struct pool_workqueue {
Tejun Heobd7bdd42012-07-12 14:46:37 -0700193 struct worker_pool *pool; /* I: the associated pool */
Tejun Heo4690c4a2010-06-29 10:07:10 +0200194 struct workqueue_struct *wq; /* I: the owning workqueue */
Tejun Heo73f53c42010-06-29 10:07:11 +0200195 int work_color; /* L: current color */
196 int flush_color; /* L: flushing color */
Tejun Heo8864b4e2013-03-12 11:30:04 -0700197 int refcnt; /* L: reference count */
Tejun Heo73f53c42010-06-29 10:07:11 +0200198 int nr_in_flight[WORK_NR_COLORS];
199 /* L: nr of in_flight works */
Tejun Heo1e19ffc2010-06-29 10:07:12 +0200200 int nr_active; /* L: nr of active works */
Tejun Heoa0a1a5f2010-06-29 10:07:12 +0200201 int max_active; /* L: max active works */
Tejun Heo1e19ffc2010-06-29 10:07:12 +0200202 struct list_head delayed_works; /* L: delayed works */
Lai Jiangshan3c25a552013-03-25 16:57:17 -0700203 struct list_head pwqs_node; /* WR: node on wq->pwqs */
Tejun Heo2e109a22013-03-13 19:47:40 -0700204 struct list_head mayday_node; /* MD: node on wq->maydays */
Tejun Heo8864b4e2013-03-12 11:30:04 -0700205
206 /*
207 * Release of unbound pwq is punted to system_wq. See put_pwq()
208 * and pwq_unbound_release_workfn() for details. pool_workqueue
209 * itself is also sched-RCU protected so that the first pwq can be
Lai Jiangshanb09f4fd2013-03-25 16:57:18 -0700210 * determined without grabbing wq->mutex.
Tejun Heo8864b4e2013-03-12 11:30:04 -0700211 */
212 struct work_struct unbound_release_work;
213 struct rcu_head rcu;
Tejun Heoe904e6c2013-03-12 11:29:57 -0700214} __aligned(1 << WORK_STRUCT_FLAG_BITS);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216/*
Tejun Heo73f53c42010-06-29 10:07:11 +0200217 * Structure used to wait for workqueue flush.
218 */
219struct wq_flusher {
Lai Jiangshan3c25a552013-03-25 16:57:17 -0700220 struct list_head list; /* WQ: list of flushers */
221 int flush_color; /* WQ: flush color waiting for */
Tejun Heo73f53c42010-06-29 10:07:11 +0200222 struct completion done; /* flush completion */
223};
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224
Tejun Heo226223a2013-03-12 11:30:05 -0700225struct wq_device;
226
Tejun Heo73f53c42010-06-29 10:07:11 +0200227/*
Tejun Heoc5aa87b2013-03-13 16:51:36 -0700228 * The externally visible workqueue. It relays the issued work items to
229 * the appropriate worker_pool through its pool_workqueues.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230 */
231struct workqueue_struct {
Lai Jiangshan3c25a552013-03-25 16:57:17 -0700232 struct list_head pwqs; /* WR: all pwqs of this wq */
Lai Jiangshan68e13a62013-03-25 16:57:17 -0700233 struct list_head list; /* PL: list of all workqueues */
Tejun Heo73f53c42010-06-29 10:07:11 +0200234
Lai Jiangshan3c25a552013-03-25 16:57:17 -0700235 struct mutex mutex; /* protects this wq */
236 int work_color; /* WQ: current work color */
237 int flush_color; /* WQ: current flush color */
Tejun Heo112202d2013-02-13 19:29:12 -0800238 atomic_t nr_pwqs_to_flush; /* flush in progress */
Lai Jiangshan3c25a552013-03-25 16:57:17 -0700239 struct wq_flusher *first_flusher; /* WQ: first flusher */
240 struct list_head flusher_queue; /* WQ: flush waiters */
241 struct list_head flusher_overflow; /* WQ: flush overflow list */
Tejun Heo73f53c42010-06-29 10:07:11 +0200242
Tejun Heo2e109a22013-03-13 19:47:40 -0700243 struct list_head maydays; /* MD: pwqs requesting rescue */
Tejun Heoe22bee72010-06-29 10:07:14 +0200244 struct worker *rescuer; /* I: rescue worker */
245
Lai Jiangshan87fc7412013-03-25 16:57:18 -0700246 int nr_drainers; /* WQ: drain in progress */
Lai Jiangshana357fc02013-03-25 16:57:19 -0700247 int saved_max_active; /* WQ: saved pwq max_active */
Tejun Heo226223a2013-03-12 11:30:05 -0700248
Tejun Heo6029a912013-04-01 11:23:34 -0700249 struct workqueue_attrs *unbound_attrs; /* WQ: only for unbound wqs */
Tejun Heo4c16bd32013-04-01 11:23:36 -0700250 struct pool_workqueue *dfl_pwq; /* WQ: only for unbound wqs */
Tejun Heo6029a912013-04-01 11:23:34 -0700251
Tejun Heo226223a2013-03-12 11:30:05 -0700252#ifdef CONFIG_SYSFS
253 struct wq_device *wq_dev; /* I: for sysfs interface */
254#endif
Johannes Berg4e6045f2007-10-18 23:39:55 -0700255#ifdef CONFIG_LOCKDEP
Tejun Heo4690c4a2010-06-29 10:07:10 +0200256 struct lockdep_map lockdep_map;
Johannes Berg4e6045f2007-10-18 23:39:55 -0700257#endif
Tejun Heoecf68812013-04-01 11:23:34 -0700258 char name[WQ_NAME_LEN]; /* I: workqueue name */
Tejun Heo2728fd22013-04-01 11:23:35 -0700259
260 /* hot fields used during command issue, aligned to cacheline */
261 unsigned int flags ____cacheline_aligned; /* WQ: WQ_* flags */
262 struct pool_workqueue __percpu *cpu_pwqs; /* I: per-cpu pwqs */
Tejun Heodf2d5ae2013-04-01 11:23:35 -0700263 struct pool_workqueue __rcu *numa_pwq_tbl[]; /* FR: unbound pwqs indexed by node */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700264};
265
Tejun Heoe904e6c2013-03-12 11:29:57 -0700266static struct kmem_cache *pwq_cache;
267
Tejun Heobce90382013-04-01 11:23:32 -0700268static int wq_numa_tbl_len; /* highest possible NUMA node id + 1 */
269static cpumask_var_t *wq_numa_possible_cpumask;
270 /* possible CPUs of each node */
271
Tejun Heod55262c2013-04-01 11:23:38 -0700272static bool wq_disable_numa;
273module_param_named(disable_numa, wq_disable_numa, bool, 0444);
274
Viresh Kumarcee22a12013-04-08 16:45:40 +0530275/* see the comment above the definition of WQ_POWER_EFFICIENT */
276#ifdef CONFIG_WQ_POWER_EFFICIENT_DEFAULT
277static bool wq_power_efficient = true;
278#else
279static bool wq_power_efficient;
280#endif
281
282module_param_named(power_efficient, wq_power_efficient, bool, 0444);
283
Tejun Heobce90382013-04-01 11:23:32 -0700284static bool wq_numa_enabled; /* unbound NUMA affinity enabled */
285
Tejun Heo4c16bd32013-04-01 11:23:36 -0700286/* buf for wq_update_unbound_numa_attrs(), protected by CPU hotplug exclusion */
287static struct workqueue_attrs *wq_update_unbound_numa_attrs_buf;
288
Lai Jiangshan68e13a62013-03-25 16:57:17 -0700289static DEFINE_MUTEX(wq_pool_mutex); /* protects pools and workqueues list */
Tejun Heo2e109a22013-03-13 19:47:40 -0700290static DEFINE_SPINLOCK(wq_mayday_lock); /* protects wq->maydays list */
Tejun Heo5bcab332013-03-13 19:47:40 -0700291
Lai Jiangshan68e13a62013-03-25 16:57:17 -0700292static LIST_HEAD(workqueues); /* PL: list of all workqueues */
293static bool workqueue_freezing; /* PL: have wqs started freezing? */
Tejun Heo7d19c5c2013-03-13 19:47:40 -0700294
295/* the per-cpu worker pools */
296static DEFINE_PER_CPU_SHARED_ALIGNED(struct worker_pool [NR_STD_WORKER_POOLS],
297 cpu_worker_pools);
298
Lai Jiangshan68e13a62013-03-25 16:57:17 -0700299static DEFINE_IDR(worker_pool_idr); /* PR: idr of all pools */
Tejun Heo7d19c5c2013-03-13 19:47:40 -0700300
Lai Jiangshan68e13a62013-03-25 16:57:17 -0700301/* PL: hash of all unbound pools keyed by pool->attrs */
Tejun Heo29c91e92013-03-12 11:30:03 -0700302static DEFINE_HASHTABLE(unbound_pool_hash, UNBOUND_POOL_HASH_ORDER);
303
Tejun Heoc5aa87b2013-03-13 16:51:36 -0700304/* I: attributes used when instantiating standard unbound pools on demand */
Tejun Heo29c91e92013-03-12 11:30:03 -0700305static struct workqueue_attrs *unbound_std_wq_attrs[NR_STD_WORKER_POOLS];
306
Tejun Heo8a2b7532013-09-05 12:30:04 -0400307/* I: attributes used when instantiating ordered pools on demand */
308static struct workqueue_attrs *ordered_wq_attrs[NR_STD_WORKER_POOLS];
309
Tejun Heod320c032010-06-29 10:07:14 +0200310struct workqueue_struct *system_wq __read_mostly;
Marc Dionnead7b1f82013-05-06 17:44:55 -0400311EXPORT_SYMBOL(system_wq);
Valentin Ilie044c7822012-08-19 00:52:42 +0300312struct workqueue_struct *system_highpri_wq __read_mostly;
Joonsoo Kim1aabe902012-08-15 23:25:39 +0900313EXPORT_SYMBOL_GPL(system_highpri_wq);
Valentin Ilie044c7822012-08-19 00:52:42 +0300314struct workqueue_struct *system_long_wq __read_mostly;
Tejun Heod320c032010-06-29 10:07:14 +0200315EXPORT_SYMBOL_GPL(system_long_wq);
Valentin Ilie044c7822012-08-19 00:52:42 +0300316struct workqueue_struct *system_unbound_wq __read_mostly;
Tejun Heof3421792010-07-02 10:03:51 +0200317EXPORT_SYMBOL_GPL(system_unbound_wq);
Valentin Ilie044c7822012-08-19 00:52:42 +0300318struct workqueue_struct *system_freezable_wq __read_mostly;
Tejun Heo24d51ad2011-02-21 09:52:50 +0100319EXPORT_SYMBOL_GPL(system_freezable_wq);
Viresh Kumar06681062013-04-24 17:12:54 +0530320struct workqueue_struct *system_power_efficient_wq __read_mostly;
321EXPORT_SYMBOL_GPL(system_power_efficient_wq);
322struct workqueue_struct *system_freezable_power_efficient_wq __read_mostly;
323EXPORT_SYMBOL_GPL(system_freezable_power_efficient_wq);
Tejun Heod320c032010-06-29 10:07:14 +0200324
Tejun Heo7d19c5c2013-03-13 19:47:40 -0700325static int worker_thread(void *__worker);
326static void copy_workqueue_attrs(struct workqueue_attrs *to,
327 const struct workqueue_attrs *from);
328
Tejun Heo97bd2342010-10-05 10:41:14 +0200329#define CREATE_TRACE_POINTS
330#include <trace/events/workqueue.h>
331
Lai Jiangshan68e13a62013-03-25 16:57:17 -0700332#define assert_rcu_or_pool_mutex() \
Tejun Heo5bcab332013-03-13 19:47:40 -0700333 rcu_lockdep_assert(rcu_read_lock_sched_held() || \
Lai Jiangshan68e13a62013-03-25 16:57:17 -0700334 lockdep_is_held(&wq_pool_mutex), \
335 "sched RCU or wq_pool_mutex should be held")
Tejun Heo5bcab332013-03-13 19:47:40 -0700336
Lai Jiangshanb09f4fd2013-03-25 16:57:18 -0700337#define assert_rcu_or_wq_mutex(wq) \
Tejun Heo76af4d92013-03-12 11:30:00 -0700338 rcu_lockdep_assert(rcu_read_lock_sched_held() || \
Lai Jiangshanb5927602013-03-25 16:57:19 -0700339 lockdep_is_held(&wq->mutex), \
Lai Jiangshanb09f4fd2013-03-25 16:57:18 -0700340 "sched RCU or wq->mutex should be held")
Tejun Heo76af4d92013-03-12 11:30:00 -0700341
Tejun Heof02ae732013-03-12 11:30:03 -0700342#define for_each_cpu_worker_pool(pool, cpu) \
343 for ((pool) = &per_cpu(cpu_worker_pools, cpu)[0]; \
344 (pool) < &per_cpu(cpu_worker_pools, cpu)[NR_STD_WORKER_POOLS]; \
Tejun Heo7a62c2c2013-03-12 11:30:03 -0700345 (pool)++)
Tejun Heo4ce62e92012-07-13 22:16:44 -0700346
Tejun Heo49e3cf42013-03-12 11:29:58 -0700347/**
Tejun Heo17116962013-03-12 11:29:58 -0700348 * for_each_pool - iterate through all worker_pools in the system
349 * @pool: iteration cursor
Tejun Heo611c92a2013-03-13 16:51:36 -0700350 * @pi: integer used for iteration
Tejun Heofa1b54e2013-03-12 11:30:00 -0700351 *
Lai Jiangshan68e13a62013-03-25 16:57:17 -0700352 * This must be called either with wq_pool_mutex held or sched RCU read
353 * locked. If the pool needs to be used beyond the locking in effect, the
354 * caller is responsible for guaranteeing that the pool stays online.
Tejun Heofa1b54e2013-03-12 11:30:00 -0700355 *
356 * The if/else clause exists only for the lockdep assertion and can be
357 * ignored.
Tejun Heo17116962013-03-12 11:29:58 -0700358 */
Tejun Heo611c92a2013-03-13 16:51:36 -0700359#define for_each_pool(pool, pi) \
360 idr_for_each_entry(&worker_pool_idr, pool, pi) \
Lai Jiangshan68e13a62013-03-25 16:57:17 -0700361 if (({ assert_rcu_or_pool_mutex(); false; })) { } \
Tejun Heofa1b54e2013-03-12 11:30:00 -0700362 else
Tejun Heo17116962013-03-12 11:29:58 -0700363
364/**
Tejun Heo822d8402013-03-19 13:45:21 -0700365 * for_each_pool_worker - iterate through all workers of a worker_pool
366 * @worker: iteration cursor
Tejun Heo822d8402013-03-19 13:45:21 -0700367 * @pool: worker_pool to iterate workers of
368 *
Lai Jiangshan9625ab12014-05-20 17:46:27 +0800369 * This must be called with @pool->manager_mutex.
Tejun Heo822d8402013-03-19 13:45:21 -0700370 *
371 * The if/else clause exists only for the lockdep assertion and can be
372 * ignored.
373 */
Lai Jiangshanda028462014-05-20 17:46:31 +0800374#define for_each_pool_worker(worker, pool) \
375 list_for_each_entry((worker), &(pool)->workers, node) \
Lai Jiangshan9625ab12014-05-20 17:46:27 +0800376 if (({ lockdep_assert_held(&pool->manager_mutex); false; })) { } \
Tejun Heo822d8402013-03-19 13:45:21 -0700377 else
378
379/**
Tejun Heo49e3cf42013-03-12 11:29:58 -0700380 * for_each_pwq - iterate through all pool_workqueues of the specified workqueue
381 * @pwq: iteration cursor
382 * @wq: the target workqueue
Tejun Heo76af4d92013-03-12 11:30:00 -0700383 *
Lai Jiangshanb09f4fd2013-03-25 16:57:18 -0700384 * This must be called either with wq->mutex held or sched RCU read locked.
Tejun Heo794b18b2013-03-13 19:47:40 -0700385 * If the pwq needs to be used beyond the locking in effect, the caller is
386 * responsible for guaranteeing that the pwq stays online.
Tejun Heo76af4d92013-03-12 11:30:00 -0700387 *
388 * The if/else clause exists only for the lockdep assertion and can be
389 * ignored.
Tejun Heo49e3cf42013-03-12 11:29:58 -0700390 */
391#define for_each_pwq(pwq, wq) \
Tejun Heo76af4d92013-03-12 11:30:00 -0700392 list_for_each_entry_rcu((pwq), &(wq)->pwqs, pwqs_node) \
Lai Jiangshanb09f4fd2013-03-25 16:57:18 -0700393 if (({ assert_rcu_or_wq_mutex(wq); false; })) { } \
Tejun Heo76af4d92013-03-12 11:30:00 -0700394 else
Tejun Heof3421792010-07-02 10:03:51 +0200395
Thomas Gleixnerdc186ad2009-11-16 01:09:48 +0900396#ifdef CONFIG_DEBUG_OBJECTS_WORK
397
398static struct debug_obj_descr work_debug_descr;
399
Stanislaw Gruszka99777282011-03-07 09:58:33 +0100400static void *work_debug_hint(void *addr)
401{
402 return ((struct work_struct *) addr)->func;
403}
404
Thomas Gleixnerdc186ad2009-11-16 01:09:48 +0900405/*
406 * fixup_init is called when:
407 * - an active object is initialized
408 */
409static int work_fixup_init(void *addr, enum debug_obj_state state)
410{
411 struct work_struct *work = addr;
412
413 switch (state) {
414 case ODEBUG_STATE_ACTIVE:
415 cancel_work_sync(work);
416 debug_object_init(work, &work_debug_descr);
417 return 1;
418 default:
419 return 0;
420 }
421}
422
423/*
424 * fixup_activate is called when:
425 * - an active object is activated
426 * - an unknown object is activated (might be a statically initialized object)
427 */
428static int work_fixup_activate(void *addr, enum debug_obj_state state)
429{
430 struct work_struct *work = addr;
431
432 switch (state) {
433
434 case ODEBUG_STATE_NOTAVAILABLE:
435 /*
436 * This is not really a fixup. The work struct was
437 * statically initialized. We just make sure that it
438 * is tracked in the object tracker.
439 */
Tejun Heo22df02b2010-06-29 10:07:10 +0200440 if (test_bit(WORK_STRUCT_STATIC_BIT, work_data_bits(work))) {
Thomas Gleixnerdc186ad2009-11-16 01:09:48 +0900441 debug_object_init(work, &work_debug_descr);
442 debug_object_activate(work, &work_debug_descr);
443 return 0;
444 }
445 WARN_ON_ONCE(1);
446 return 0;
447
448 case ODEBUG_STATE_ACTIVE:
449 WARN_ON(1);
450
451 default:
452 return 0;
453 }
454}
455
456/*
457 * fixup_free is called when:
458 * - an active object is freed
459 */
460static int work_fixup_free(void *addr, enum debug_obj_state state)
461{
462 struct work_struct *work = addr;
463
464 switch (state) {
465 case ODEBUG_STATE_ACTIVE:
466 cancel_work_sync(work);
467 debug_object_free(work, &work_debug_descr);
468 return 1;
469 default:
470 return 0;
471 }
472}
473
474static struct debug_obj_descr work_debug_descr = {
475 .name = "work_struct",
Stanislaw Gruszka99777282011-03-07 09:58:33 +0100476 .debug_hint = work_debug_hint,
Thomas Gleixnerdc186ad2009-11-16 01:09:48 +0900477 .fixup_init = work_fixup_init,
478 .fixup_activate = work_fixup_activate,
479 .fixup_free = work_fixup_free,
480};
481
482static inline void debug_work_activate(struct work_struct *work)
483{
484 debug_object_activate(work, &work_debug_descr);
485}
486
487static inline void debug_work_deactivate(struct work_struct *work)
488{
489 debug_object_deactivate(work, &work_debug_descr);
490}
491
492void __init_work(struct work_struct *work, int onstack)
493{
494 if (onstack)
495 debug_object_init_on_stack(work, &work_debug_descr);
496 else
497 debug_object_init(work, &work_debug_descr);
498}
499EXPORT_SYMBOL_GPL(__init_work);
500
501void destroy_work_on_stack(struct work_struct *work)
502{
503 debug_object_free(work, &work_debug_descr);
504}
505EXPORT_SYMBOL_GPL(destroy_work_on_stack);
506
Thomas Gleixnerea2e64f2014-03-23 14:20:44 +0000507void destroy_delayed_work_on_stack(struct delayed_work *work)
508{
509 destroy_timer_on_stack(&work->timer);
510 debug_object_free(&work->work, &work_debug_descr);
511}
512EXPORT_SYMBOL_GPL(destroy_delayed_work_on_stack);
513
Thomas Gleixnerdc186ad2009-11-16 01:09:48 +0900514#else
515static inline void debug_work_activate(struct work_struct *work) { }
516static inline void debug_work_deactivate(struct work_struct *work) { }
517#endif
518
Li Bin4e8b22b2013-09-10 09:52:35 +0800519/**
520 * worker_pool_assign_id - allocate ID and assing it to @pool
521 * @pool: the pool pointer of interest
522 *
523 * Returns 0 if ID in [0, WORK_OFFQ_POOL_NONE) is allocated and assigned
524 * successfully, -errno on failure.
525 */
Tejun Heo9daf9e62013-01-24 11:01:33 -0800526static int worker_pool_assign_id(struct worker_pool *pool)
527{
528 int ret;
529
Lai Jiangshan68e13a62013-03-25 16:57:17 -0700530 lockdep_assert_held(&wq_pool_mutex);
Tejun Heo5bcab332013-03-13 19:47:40 -0700531
Li Bin4e8b22b2013-09-10 09:52:35 +0800532 ret = idr_alloc(&worker_pool_idr, pool, 0, WORK_OFFQ_POOL_NONE,
533 GFP_KERNEL);
Tejun Heo229641a2013-04-01 17:08:13 -0700534 if (ret >= 0) {
Tejun Heoe68035f2013-03-13 14:59:38 -0700535 pool->id = ret;
Tejun Heo229641a2013-04-01 17:08:13 -0700536 return 0;
537 }
Tejun Heo9daf9e62013-01-24 11:01:33 -0800538 return ret;
539}
540
Tejun Heo76af4d92013-03-12 11:30:00 -0700541/**
Tejun Heodf2d5ae2013-04-01 11:23:35 -0700542 * unbound_pwq_by_node - return the unbound pool_workqueue for the given node
543 * @wq: the target workqueue
544 * @node: the node ID
545 *
546 * This must be called either with pwq_lock held or sched RCU read locked.
547 * If the pwq needs to be used beyond the locking in effect, the caller is
548 * responsible for guaranteeing that the pwq stays online.
Yacine Belkadid185af32013-07-31 14:59:24 -0700549 *
550 * Return: The unbound pool_workqueue for @node.
Tejun Heodf2d5ae2013-04-01 11:23:35 -0700551 */
552static struct pool_workqueue *unbound_pwq_by_node(struct workqueue_struct *wq,
553 int node)
554{
555 assert_rcu_or_wq_mutex(wq);
556 return rcu_dereference_raw(wq->numa_pwq_tbl[node]);
557}
558
Tejun Heo73f53c42010-06-29 10:07:11 +0200559static unsigned int work_color_to_flags(int color)
560{
561 return color << WORK_STRUCT_COLOR_SHIFT;
562}
563
564static int get_work_color(struct work_struct *work)
565{
566 return (*work_data_bits(work) >> WORK_STRUCT_COLOR_SHIFT) &
567 ((1 << WORK_STRUCT_COLOR_BITS) - 1);
568}
569
570static int work_next_color(int color)
571{
572 return (color + 1) % WORK_NR_COLORS;
Oleg Nesterova848e3b2007-05-09 02:34:17 -0700573}
574
David Howells4594bf12006-12-07 11:33:26 +0000575/*
Tejun Heo112202d2013-02-13 19:29:12 -0800576 * While queued, %WORK_STRUCT_PWQ is set and non flag bits of a work's data
577 * contain the pointer to the queued pwq. Once execution starts, the flag
Tejun Heo7c3eed52013-01-24 11:01:33 -0800578 * is cleared and the high bits contain OFFQ flags and pool ID.
Tejun Heo7a22ad72010-06-29 10:07:13 +0200579 *
Tejun Heo112202d2013-02-13 19:29:12 -0800580 * set_work_pwq(), set_work_pool_and_clear_pending(), mark_work_canceling()
581 * and clear_work_data() can be used to set the pwq, pool or clear
Tejun Heobbb68df2012-08-03 10:30:46 -0700582 * work->data. These functions should only be called while the work is
583 * owned - ie. while the PENDING bit is set.
Tejun Heo7a22ad72010-06-29 10:07:13 +0200584 *
Tejun Heo112202d2013-02-13 19:29:12 -0800585 * get_work_pool() and get_work_pwq() can be used to obtain the pool or pwq
Tejun Heo7c3eed52013-01-24 11:01:33 -0800586 * corresponding to a work. Pool is available once the work has been
Tejun Heo112202d2013-02-13 19:29:12 -0800587 * queued anywhere after initialization until it is sync canceled. pwq is
Tejun Heo7c3eed52013-01-24 11:01:33 -0800588 * available only while the work item is queued.
Tejun Heobbb68df2012-08-03 10:30:46 -0700589 *
590 * %WORK_OFFQ_CANCELING is used to mark a work item which is being
591 * canceled. While being canceled, a work item may have its PENDING set
592 * but stay off timer and worklist for arbitrarily long and nobody should
593 * try to steal the PENDING bit.
David Howells4594bf12006-12-07 11:33:26 +0000594 */
Tejun Heo7a22ad72010-06-29 10:07:13 +0200595static inline void set_work_data(struct work_struct *work, unsigned long data,
596 unsigned long flags)
David Howells365970a2006-11-22 14:54:49 +0000597{
Tejun Heo6183c002013-03-12 11:29:57 -0700598 WARN_ON_ONCE(!work_pending(work));
Tejun Heo7a22ad72010-06-29 10:07:13 +0200599 atomic_long_set(&work->data, data | flags | work_static(work));
David Howells365970a2006-11-22 14:54:49 +0000600}
David Howells365970a2006-11-22 14:54:49 +0000601
Tejun Heo112202d2013-02-13 19:29:12 -0800602static void set_work_pwq(struct work_struct *work, struct pool_workqueue *pwq,
Tejun Heo7a22ad72010-06-29 10:07:13 +0200603 unsigned long extra_flags)
Oleg Nesterov4d707b92010-04-23 17:40:40 +0200604{
Tejun Heo112202d2013-02-13 19:29:12 -0800605 set_work_data(work, (unsigned long)pwq,
606 WORK_STRUCT_PENDING | WORK_STRUCT_PWQ | extra_flags);
Oleg Nesterov4d707b92010-04-23 17:40:40 +0200607}
608
Lai Jiangshan4468a002013-02-06 18:04:53 -0800609static void set_work_pool_and_keep_pending(struct work_struct *work,
610 int pool_id)
611{
612 set_work_data(work, (unsigned long)pool_id << WORK_OFFQ_POOL_SHIFT,
613 WORK_STRUCT_PENDING);
614}
615
Tejun Heo7c3eed52013-01-24 11:01:33 -0800616static void set_work_pool_and_clear_pending(struct work_struct *work,
617 int pool_id)
David Howells365970a2006-11-22 14:54:49 +0000618{
Tejun Heo23657bb2012-08-13 17:08:19 -0700619 /*
620 * The following wmb is paired with the implied mb in
621 * test_and_set_bit(PENDING) and ensures all updates to @work made
622 * here are visible to and precede any updates by the next PENDING
623 * owner.
624 */
625 smp_wmb();
Tejun Heo7c3eed52013-01-24 11:01:33 -0800626 set_work_data(work, (unsigned long)pool_id << WORK_OFFQ_POOL_SHIFT, 0);
Tejun Heo7a22ad72010-06-29 10:07:13 +0200627}
628
629static void clear_work_data(struct work_struct *work)
630{
Tejun Heo7c3eed52013-01-24 11:01:33 -0800631 smp_wmb(); /* see set_work_pool_and_clear_pending() */
632 set_work_data(work, WORK_STRUCT_NO_POOL, 0);
Tejun Heo7a22ad72010-06-29 10:07:13 +0200633}
634
Tejun Heo112202d2013-02-13 19:29:12 -0800635static struct pool_workqueue *get_work_pwq(struct work_struct *work)
Tejun Heo7a22ad72010-06-29 10:07:13 +0200636{
Tejun Heoe1201532010-07-22 14:14:25 +0200637 unsigned long data = atomic_long_read(&work->data);
Tejun Heo7a22ad72010-06-29 10:07:13 +0200638
Tejun Heo112202d2013-02-13 19:29:12 -0800639 if (data & WORK_STRUCT_PWQ)
Tejun Heoe1201532010-07-22 14:14:25 +0200640 return (void *)(data & WORK_STRUCT_WQ_DATA_MASK);
641 else
642 return NULL;
Tejun Heo7a22ad72010-06-29 10:07:13 +0200643}
644
Tejun Heo7c3eed52013-01-24 11:01:33 -0800645/**
646 * get_work_pool - return the worker_pool a given work was associated with
647 * @work: the work item of interest
648 *
Lai Jiangshan68e13a62013-03-25 16:57:17 -0700649 * Pools are created and destroyed under wq_pool_mutex, and allows read
650 * access under sched-RCU read lock. As such, this function should be
651 * called under wq_pool_mutex or with preemption disabled.
Tejun Heofa1b54e2013-03-12 11:30:00 -0700652 *
653 * All fields of the returned pool are accessible as long as the above
654 * mentioned locking is in effect. If the returned pool needs to be used
655 * beyond the critical section, the caller is responsible for ensuring the
656 * returned pool is and stays online.
Yacine Belkadid185af32013-07-31 14:59:24 -0700657 *
658 * Return: The worker_pool @work was last associated with. %NULL if none.
Tejun Heo7c3eed52013-01-24 11:01:33 -0800659 */
660static struct worker_pool *get_work_pool(struct work_struct *work)
Tejun Heo7a22ad72010-06-29 10:07:13 +0200661{
Tejun Heoe1201532010-07-22 14:14:25 +0200662 unsigned long data = atomic_long_read(&work->data);
Tejun Heo7c3eed52013-01-24 11:01:33 -0800663 int pool_id;
Tejun Heo7a22ad72010-06-29 10:07:13 +0200664
Lai Jiangshan68e13a62013-03-25 16:57:17 -0700665 assert_rcu_or_pool_mutex();
Tejun Heofa1b54e2013-03-12 11:30:00 -0700666
Tejun Heo112202d2013-02-13 19:29:12 -0800667 if (data & WORK_STRUCT_PWQ)
668 return ((struct pool_workqueue *)
Tejun Heo7c3eed52013-01-24 11:01:33 -0800669 (data & WORK_STRUCT_WQ_DATA_MASK))->pool;
Tejun Heo7a22ad72010-06-29 10:07:13 +0200670
Tejun Heo7c3eed52013-01-24 11:01:33 -0800671 pool_id = data >> WORK_OFFQ_POOL_SHIFT;
672 if (pool_id == WORK_OFFQ_POOL_NONE)
Tejun Heo7a22ad72010-06-29 10:07:13 +0200673 return NULL;
674
Tejun Heofa1b54e2013-03-12 11:30:00 -0700675 return idr_find(&worker_pool_idr, pool_id);
Tejun Heo7c3eed52013-01-24 11:01:33 -0800676}
677
678/**
679 * get_work_pool_id - return the worker pool ID a given work is associated with
680 * @work: the work item of interest
681 *
Yacine Belkadid185af32013-07-31 14:59:24 -0700682 * Return: The worker_pool ID @work was last associated with.
Tejun Heo7c3eed52013-01-24 11:01:33 -0800683 * %WORK_OFFQ_POOL_NONE if none.
684 */
685static int get_work_pool_id(struct work_struct *work)
686{
Lai Jiangshan54d5b7d2013-02-07 13:14:20 -0800687 unsigned long data = atomic_long_read(&work->data);
Tejun Heo7c3eed52013-01-24 11:01:33 -0800688
Tejun Heo112202d2013-02-13 19:29:12 -0800689 if (data & WORK_STRUCT_PWQ)
690 return ((struct pool_workqueue *)
Lai Jiangshan54d5b7d2013-02-07 13:14:20 -0800691 (data & WORK_STRUCT_WQ_DATA_MASK))->pool->id;
692
693 return data >> WORK_OFFQ_POOL_SHIFT;
Tejun Heo7c3eed52013-01-24 11:01:33 -0800694}
695
Tejun Heobbb68df2012-08-03 10:30:46 -0700696static void mark_work_canceling(struct work_struct *work)
697{
Tejun Heo7c3eed52013-01-24 11:01:33 -0800698 unsigned long pool_id = get_work_pool_id(work);
Tejun Heobbb68df2012-08-03 10:30:46 -0700699
Tejun Heo7c3eed52013-01-24 11:01:33 -0800700 pool_id <<= WORK_OFFQ_POOL_SHIFT;
701 set_work_data(work, pool_id | WORK_OFFQ_CANCELING, WORK_STRUCT_PENDING);
Tejun Heobbb68df2012-08-03 10:30:46 -0700702}
703
704static bool work_is_canceling(struct work_struct *work)
705{
706 unsigned long data = atomic_long_read(&work->data);
707
Tejun Heo112202d2013-02-13 19:29:12 -0800708 return !(data & WORK_STRUCT_PWQ) && (data & WORK_OFFQ_CANCELING);
Tejun Heobbb68df2012-08-03 10:30:46 -0700709}
710
David Howells365970a2006-11-22 14:54:49 +0000711/*
Tejun Heo32704762012-07-13 22:16:45 -0700712 * Policy functions. These define the policies on how the global worker
713 * pools are managed. Unless noted otherwise, these functions assume that
Tejun Heod565ed62013-01-24 11:01:33 -0800714 * they're being called with pool->lock held.
David Howells365970a2006-11-22 14:54:49 +0000715 */
Tejun Heoe22bee72010-06-29 10:07:14 +0200716
Tejun Heo63d95a92012-07-12 14:46:37 -0700717static bool __need_more_worker(struct worker_pool *pool)
David Howells365970a2006-11-22 14:54:49 +0000718{
Tejun Heoe19e3972013-01-24 11:39:44 -0800719 return !atomic_read(&pool->nr_running);
David Howells365970a2006-11-22 14:54:49 +0000720}
721
Tejun Heoe22bee72010-06-29 10:07:14 +0200722/*
723 * Need to wake up a worker? Called from anything but currently
724 * running workers.
Tejun Heo974271c2012-07-12 14:46:37 -0700725 *
726 * Note that, because unbound workers never contribute to nr_running, this
Tejun Heo706026c2013-01-24 11:01:34 -0800727 * function will always return %true for unbound pools as long as the
Tejun Heo974271c2012-07-12 14:46:37 -0700728 * worklist isn't empty.
Tejun Heoe22bee72010-06-29 10:07:14 +0200729 */
Tejun Heo63d95a92012-07-12 14:46:37 -0700730static bool need_more_worker(struct worker_pool *pool)
David Howells365970a2006-11-22 14:54:49 +0000731{
Tejun Heo63d95a92012-07-12 14:46:37 -0700732 return !list_empty(&pool->worklist) && __need_more_worker(pool);
David Howells365970a2006-11-22 14:54:49 +0000733}
734
Tejun Heoe22bee72010-06-29 10:07:14 +0200735/* Can I start working? Called from busy but !running workers. */
Tejun Heo63d95a92012-07-12 14:46:37 -0700736static bool may_start_working(struct worker_pool *pool)
Tejun Heoe22bee72010-06-29 10:07:14 +0200737{
Tejun Heo63d95a92012-07-12 14:46:37 -0700738 return pool->nr_idle;
Tejun Heoe22bee72010-06-29 10:07:14 +0200739}
740
741/* Do I need to keep working? Called from currently running workers. */
Tejun Heo63d95a92012-07-12 14:46:37 -0700742static bool keep_working(struct worker_pool *pool)
Tejun Heoe22bee72010-06-29 10:07:14 +0200743{
Tejun Heoe19e3972013-01-24 11:39:44 -0800744 return !list_empty(&pool->worklist) &&
745 atomic_read(&pool->nr_running) <= 1;
Tejun Heoe22bee72010-06-29 10:07:14 +0200746}
747
748/* Do we need a new worker? Called from manager. */
Tejun Heo63d95a92012-07-12 14:46:37 -0700749static bool need_to_create_worker(struct worker_pool *pool)
Tejun Heoe22bee72010-06-29 10:07:14 +0200750{
Tejun Heo63d95a92012-07-12 14:46:37 -0700751 return need_more_worker(pool) && !may_start_working(pool);
Tejun Heoe22bee72010-06-29 10:07:14 +0200752}
753
Tejun Heoe22bee72010-06-29 10:07:14 +0200754/* Do we have too many workers and should some go away? */
Tejun Heo63d95a92012-07-12 14:46:37 -0700755static bool too_many_workers(struct worker_pool *pool)
Tejun Heoe22bee72010-06-29 10:07:14 +0200756{
Tejun Heo34a06bd2013-03-12 11:30:00 -0700757 bool managing = mutex_is_locked(&pool->manager_arb);
Tejun Heo63d95a92012-07-12 14:46:37 -0700758 int nr_idle = pool->nr_idle + managing; /* manager is considered idle */
759 int nr_busy = pool->nr_workers - nr_idle;
Tejun Heoe22bee72010-06-29 10:07:14 +0200760
Lai Jiangshanea1abd62012-09-18 09:59:22 -0700761 /*
762 * nr_idle and idle_list may disagree if idle rebinding is in
763 * progress. Never return %true if idle_list is empty.
764 */
765 if (list_empty(&pool->idle_list))
766 return false;
767
Tejun Heoe22bee72010-06-29 10:07:14 +0200768 return nr_idle > 2 && (nr_idle - 2) * MAX_IDLE_WORKERS_RATIO >= nr_busy;
769}
770
771/*
772 * Wake up functions.
773 */
774
Tejun Heo7e116292010-06-29 10:07:13 +0200775/* Return the first worker. Safe with preemption disabled */
Tejun Heo63d95a92012-07-12 14:46:37 -0700776static struct worker *first_worker(struct worker_pool *pool)
Tejun Heo7e116292010-06-29 10:07:13 +0200777{
Tejun Heo63d95a92012-07-12 14:46:37 -0700778 if (unlikely(list_empty(&pool->idle_list)))
Tejun Heo7e116292010-06-29 10:07:13 +0200779 return NULL;
780
Tejun Heo63d95a92012-07-12 14:46:37 -0700781 return list_first_entry(&pool->idle_list, struct worker, entry);
Tejun Heo7e116292010-06-29 10:07:13 +0200782}
783
784/**
785 * wake_up_worker - wake up an idle worker
Tejun Heo63d95a92012-07-12 14:46:37 -0700786 * @pool: worker pool to wake worker from
Tejun Heo7e116292010-06-29 10:07:13 +0200787 *
Tejun Heo63d95a92012-07-12 14:46:37 -0700788 * Wake up the first idle worker of @pool.
Tejun Heo7e116292010-06-29 10:07:13 +0200789 *
790 * CONTEXT:
Tejun Heod565ed62013-01-24 11:01:33 -0800791 * spin_lock_irq(pool->lock).
Tejun Heo7e116292010-06-29 10:07:13 +0200792 */
Tejun Heo63d95a92012-07-12 14:46:37 -0700793static void wake_up_worker(struct worker_pool *pool)
Tejun Heo7e116292010-06-29 10:07:13 +0200794{
Tejun Heo63d95a92012-07-12 14:46:37 -0700795 struct worker *worker = first_worker(pool);
Tejun Heo7e116292010-06-29 10:07:13 +0200796
797 if (likely(worker))
798 wake_up_process(worker->task);
799}
800
Tejun Heo4690c4a2010-06-29 10:07:10 +0200801/**
Tejun Heoe22bee72010-06-29 10:07:14 +0200802 * wq_worker_waking_up - a worker is waking up
803 * @task: task waking up
804 * @cpu: CPU @task is waking up to
805 *
806 * This function is called during try_to_wake_up() when a worker is
807 * being awoken.
808 *
809 * CONTEXT:
810 * spin_lock_irq(rq->lock)
811 */
Tejun Heod84ff052013-03-12 11:29:59 -0700812void wq_worker_waking_up(struct task_struct *task, int cpu)
Tejun Heoe22bee72010-06-29 10:07:14 +0200813{
814 struct worker *worker = kthread_data(task);
815
Joonsoo Kim36576002012-10-26 23:03:49 +0900816 if (!(worker->flags & WORKER_NOT_RUNNING)) {
Tejun Heoec22ca52013-01-24 11:01:33 -0800817 WARN_ON_ONCE(worker->pool->cpu != cpu);
Tejun Heoe19e3972013-01-24 11:39:44 -0800818 atomic_inc(&worker->pool->nr_running);
Joonsoo Kim36576002012-10-26 23:03:49 +0900819 }
Tejun Heoe22bee72010-06-29 10:07:14 +0200820}
821
822/**
823 * wq_worker_sleeping - a worker is going to sleep
824 * @task: task going to sleep
825 * @cpu: CPU in question, must be the current CPU number
826 *
827 * This function is called during schedule() when a busy worker is
828 * going to sleep. Worker on the same cpu can be woken up by
829 * returning pointer to its task.
830 *
831 * CONTEXT:
832 * spin_lock_irq(rq->lock)
833 *
Yacine Belkadid185af32013-07-31 14:59:24 -0700834 * Return:
Tejun Heoe22bee72010-06-29 10:07:14 +0200835 * Worker task on @cpu to wake up, %NULL if none.
836 */
Tejun Heod84ff052013-03-12 11:29:59 -0700837struct task_struct *wq_worker_sleeping(struct task_struct *task, int cpu)
Tejun Heoe22bee72010-06-29 10:07:14 +0200838{
839 struct worker *worker = kthread_data(task), *to_wakeup = NULL;
Tejun Heo111c2252013-01-17 17:16:24 -0800840 struct worker_pool *pool;
Tejun Heoe22bee72010-06-29 10:07:14 +0200841
Tejun Heo111c2252013-01-17 17:16:24 -0800842 /*
843 * Rescuers, which may not have all the fields set up like normal
844 * workers, also reach here, let's not access anything before
845 * checking NOT_RUNNING.
846 */
Steven Rostedt2d646722010-12-03 23:12:33 -0500847 if (worker->flags & WORKER_NOT_RUNNING)
Tejun Heoe22bee72010-06-29 10:07:14 +0200848 return NULL;
849
Tejun Heo111c2252013-01-17 17:16:24 -0800850 pool = worker->pool;
Tejun Heo111c2252013-01-17 17:16:24 -0800851
Tejun Heoe22bee72010-06-29 10:07:14 +0200852 /* this can only happen on the local cpu */
Tejun Heo6183c002013-03-12 11:29:57 -0700853 if (WARN_ON_ONCE(cpu != raw_smp_processor_id()))
854 return NULL;
Tejun Heoe22bee72010-06-29 10:07:14 +0200855
856 /*
857 * The counterpart of the following dec_and_test, implied mb,
858 * worklist not empty test sequence is in insert_work().
859 * Please read comment there.
860 *
Tejun Heo628c78e2012-07-17 12:39:27 -0700861 * NOT_RUNNING is clear. This means that we're bound to and
862 * running on the local cpu w/ rq lock held and preemption
863 * disabled, which in turn means that none else could be
Tejun Heod565ed62013-01-24 11:01:33 -0800864 * manipulating idle_list, so dereferencing idle_list without pool
Tejun Heo628c78e2012-07-17 12:39:27 -0700865 * lock is safe.
Tejun Heoe22bee72010-06-29 10:07:14 +0200866 */
Tejun Heoe19e3972013-01-24 11:39:44 -0800867 if (atomic_dec_and_test(&pool->nr_running) &&
868 !list_empty(&pool->worklist))
Tejun Heo63d95a92012-07-12 14:46:37 -0700869 to_wakeup = first_worker(pool);
Tejun Heoe22bee72010-06-29 10:07:14 +0200870 return to_wakeup ? to_wakeup->task : NULL;
871}
872
873/**
874 * worker_set_flags - set worker flags and adjust nr_running accordingly
Tejun Heocb444762010-07-02 10:03:50 +0200875 * @worker: self
Tejun Heod302f012010-06-29 10:07:13 +0200876 * @flags: flags to set
877 * @wakeup: wakeup an idle worker if necessary
878 *
Tejun Heoe22bee72010-06-29 10:07:14 +0200879 * Set @flags in @worker->flags and adjust nr_running accordingly. If
880 * nr_running becomes zero and @wakeup is %true, an idle worker is
881 * woken up.
Tejun Heod302f012010-06-29 10:07:13 +0200882 *
Tejun Heocb444762010-07-02 10:03:50 +0200883 * CONTEXT:
Tejun Heod565ed62013-01-24 11:01:33 -0800884 * spin_lock_irq(pool->lock)
Tejun Heod302f012010-06-29 10:07:13 +0200885 */
886static inline void worker_set_flags(struct worker *worker, unsigned int flags,
887 bool wakeup)
888{
Tejun Heobd7bdd42012-07-12 14:46:37 -0700889 struct worker_pool *pool = worker->pool;
Tejun Heoe22bee72010-06-29 10:07:14 +0200890
Tejun Heocb444762010-07-02 10:03:50 +0200891 WARN_ON_ONCE(worker->task != current);
892
Tejun Heoe22bee72010-06-29 10:07:14 +0200893 /*
894 * If transitioning into NOT_RUNNING, adjust nr_running and
895 * wake up an idle worker as necessary if requested by
896 * @wakeup.
897 */
898 if ((flags & WORKER_NOT_RUNNING) &&
899 !(worker->flags & WORKER_NOT_RUNNING)) {
Tejun Heoe22bee72010-06-29 10:07:14 +0200900 if (wakeup) {
Tejun Heoe19e3972013-01-24 11:39:44 -0800901 if (atomic_dec_and_test(&pool->nr_running) &&
Tejun Heobd7bdd42012-07-12 14:46:37 -0700902 !list_empty(&pool->worklist))
Tejun Heo63d95a92012-07-12 14:46:37 -0700903 wake_up_worker(pool);
Tejun Heoe22bee72010-06-29 10:07:14 +0200904 } else
Tejun Heoe19e3972013-01-24 11:39:44 -0800905 atomic_dec(&pool->nr_running);
Tejun Heoe22bee72010-06-29 10:07:14 +0200906 }
907
Tejun Heod302f012010-06-29 10:07:13 +0200908 worker->flags |= flags;
909}
910
911/**
Tejun Heoe22bee72010-06-29 10:07:14 +0200912 * worker_clr_flags - clear worker flags and adjust nr_running accordingly
Tejun Heocb444762010-07-02 10:03:50 +0200913 * @worker: self
Tejun Heod302f012010-06-29 10:07:13 +0200914 * @flags: flags to clear
915 *
Tejun Heoe22bee72010-06-29 10:07:14 +0200916 * Clear @flags in @worker->flags and adjust nr_running accordingly.
Tejun Heod302f012010-06-29 10:07:13 +0200917 *
Tejun Heocb444762010-07-02 10:03:50 +0200918 * CONTEXT:
Tejun Heod565ed62013-01-24 11:01:33 -0800919 * spin_lock_irq(pool->lock)
Tejun Heod302f012010-06-29 10:07:13 +0200920 */
921static inline void worker_clr_flags(struct worker *worker, unsigned int flags)
922{
Tejun Heo63d95a92012-07-12 14:46:37 -0700923 struct worker_pool *pool = worker->pool;
Tejun Heoe22bee72010-06-29 10:07:14 +0200924 unsigned int oflags = worker->flags;
925
Tejun Heocb444762010-07-02 10:03:50 +0200926 WARN_ON_ONCE(worker->task != current);
927
Tejun Heod302f012010-06-29 10:07:13 +0200928 worker->flags &= ~flags;
Tejun Heoe22bee72010-06-29 10:07:14 +0200929
Tejun Heo42c025f2011-01-11 15:58:49 +0100930 /*
931 * If transitioning out of NOT_RUNNING, increment nr_running. Note
932 * that the nested NOT_RUNNING is not a noop. NOT_RUNNING is mask
933 * of multiple flags, not a single flag.
934 */
Tejun Heoe22bee72010-06-29 10:07:14 +0200935 if ((flags & WORKER_NOT_RUNNING) && (oflags & WORKER_NOT_RUNNING))
936 if (!(worker->flags & WORKER_NOT_RUNNING))
Tejun Heoe19e3972013-01-24 11:39:44 -0800937 atomic_inc(&pool->nr_running);
Tejun Heod302f012010-06-29 10:07:13 +0200938}
939
940/**
Tejun Heo8cca0ee2010-06-29 10:07:13 +0200941 * find_worker_executing_work - find worker which is executing a work
Tejun Heoc9e7cf22013-01-24 11:01:33 -0800942 * @pool: pool of interest
Tejun Heo8cca0ee2010-06-29 10:07:13 +0200943 * @work: work to find worker for
944 *
Tejun Heoc9e7cf22013-01-24 11:01:33 -0800945 * Find a worker which is executing @work on @pool by searching
946 * @pool->busy_hash which is keyed by the address of @work. For a worker
Tejun Heoa2c1c572012-12-18 10:35:02 -0800947 * to match, its current execution should match the address of @work and
948 * its work function. This is to avoid unwanted dependency between
949 * unrelated work executions through a work item being recycled while still
950 * being executed.
951 *
952 * This is a bit tricky. A work item may be freed once its execution
953 * starts and nothing prevents the freed area from being recycled for
954 * another work item. If the same work item address ends up being reused
955 * before the original execution finishes, workqueue will identify the
956 * recycled work item as currently executing and make it wait until the
957 * current execution finishes, introducing an unwanted dependency.
958 *
Tejun Heoc5aa87b2013-03-13 16:51:36 -0700959 * This function checks the work item address and work function to avoid
960 * false positives. Note that this isn't complete as one may construct a
961 * work function which can introduce dependency onto itself through a
962 * recycled work item. Well, if somebody wants to shoot oneself in the
963 * foot that badly, there's only so much we can do, and if such deadlock
964 * actually occurs, it should be easy to locate the culprit work function.
Tejun Heo8cca0ee2010-06-29 10:07:13 +0200965 *
966 * CONTEXT:
Tejun Heod565ed62013-01-24 11:01:33 -0800967 * spin_lock_irq(pool->lock).
Tejun Heo8cca0ee2010-06-29 10:07:13 +0200968 *
Yacine Belkadid185af32013-07-31 14:59:24 -0700969 * Return:
970 * Pointer to worker which is executing @work if found, %NULL
Tejun Heo8cca0ee2010-06-29 10:07:13 +0200971 * otherwise.
972 */
Tejun Heoc9e7cf22013-01-24 11:01:33 -0800973static struct worker *find_worker_executing_work(struct worker_pool *pool,
Tejun Heo8cca0ee2010-06-29 10:07:13 +0200974 struct work_struct *work)
975{
Sasha Levin42f85702012-12-17 10:01:23 -0500976 struct worker *worker;
Sasha Levin42f85702012-12-17 10:01:23 -0500977
Sasha Levinb67bfe02013-02-27 17:06:00 -0800978 hash_for_each_possible(pool->busy_hash, worker, hentry,
Tejun Heoa2c1c572012-12-18 10:35:02 -0800979 (unsigned long)work)
980 if (worker->current_work == work &&
981 worker->current_func == work->func)
Sasha Levin42f85702012-12-17 10:01:23 -0500982 return worker;
983
984 return NULL;
Tejun Heo8cca0ee2010-06-29 10:07:13 +0200985}
986
987/**
Tejun Heobf4ede02012-08-03 10:30:46 -0700988 * move_linked_works - move linked works to a list
989 * @work: start of series of works to be scheduled
990 * @head: target list to append @work to
991 * @nextp: out paramter for nested worklist walking
992 *
993 * Schedule linked works starting from @work to @head. Work series to
994 * be scheduled starts at @work and includes any consecutive work with
995 * WORK_STRUCT_LINKED set in its predecessor.
996 *
997 * If @nextp is not NULL, it's updated to point to the next work of
998 * the last scheduled work. This allows move_linked_works() to be
999 * nested inside outer list_for_each_entry_safe().
1000 *
1001 * CONTEXT:
Tejun Heod565ed62013-01-24 11:01:33 -08001002 * spin_lock_irq(pool->lock).
Tejun Heobf4ede02012-08-03 10:30:46 -07001003 */
1004static void move_linked_works(struct work_struct *work, struct list_head *head,
1005 struct work_struct **nextp)
1006{
1007 struct work_struct *n;
1008
1009 /*
1010 * Linked worklist will always end before the end of the list,
1011 * use NULL for list head.
1012 */
1013 list_for_each_entry_safe_from(work, n, NULL, entry) {
1014 list_move_tail(&work->entry, head);
1015 if (!(*work_data_bits(work) & WORK_STRUCT_LINKED))
1016 break;
1017 }
1018
1019 /*
1020 * If we're already inside safe list traversal and have moved
1021 * multiple works to the scheduled queue, the next position
1022 * needs to be updated.
1023 */
1024 if (nextp)
1025 *nextp = n;
1026}
1027
Tejun Heo8864b4e2013-03-12 11:30:04 -07001028/**
1029 * get_pwq - get an extra reference on the specified pool_workqueue
1030 * @pwq: pool_workqueue to get
1031 *
1032 * Obtain an extra reference on @pwq. The caller should guarantee that
1033 * @pwq has positive refcnt and be holding the matching pool->lock.
1034 */
1035static void get_pwq(struct pool_workqueue *pwq)
1036{
1037 lockdep_assert_held(&pwq->pool->lock);
1038 WARN_ON_ONCE(pwq->refcnt <= 0);
1039 pwq->refcnt++;
1040}
1041
1042/**
1043 * put_pwq - put a pool_workqueue reference
1044 * @pwq: pool_workqueue to put
1045 *
1046 * Drop a reference of @pwq. If its refcnt reaches zero, schedule its
1047 * destruction. The caller should be holding the matching pool->lock.
1048 */
1049static void put_pwq(struct pool_workqueue *pwq)
1050{
1051 lockdep_assert_held(&pwq->pool->lock);
1052 if (likely(--pwq->refcnt))
1053 return;
1054 if (WARN_ON_ONCE(!(pwq->wq->flags & WQ_UNBOUND)))
1055 return;
1056 /*
1057 * @pwq can't be released under pool->lock, bounce to
1058 * pwq_unbound_release_workfn(). This never recurses on the same
1059 * pool->lock as this path is taken only for unbound workqueues and
1060 * the release work item is scheduled on a per-cpu workqueue. To
1061 * avoid lockdep warning, unbound pool->locks are given lockdep
1062 * subclass of 1 in get_unbound_pool().
1063 */
1064 schedule_work(&pwq->unbound_release_work);
1065}
1066
Tejun Heodce90d42013-04-01 11:23:35 -07001067/**
1068 * put_pwq_unlocked - put_pwq() with surrounding pool lock/unlock
1069 * @pwq: pool_workqueue to put (can be %NULL)
1070 *
1071 * put_pwq() with locking. This function also allows %NULL @pwq.
1072 */
1073static void put_pwq_unlocked(struct pool_workqueue *pwq)
1074{
1075 if (pwq) {
1076 /*
1077 * As both pwqs and pools are sched-RCU protected, the
1078 * following lock operations are safe.
1079 */
1080 spin_lock_irq(&pwq->pool->lock);
1081 put_pwq(pwq);
1082 spin_unlock_irq(&pwq->pool->lock);
1083 }
1084}
1085
Tejun Heo112202d2013-02-13 19:29:12 -08001086static void pwq_activate_delayed_work(struct work_struct *work)
Tejun Heobf4ede02012-08-03 10:30:46 -07001087{
Tejun Heo112202d2013-02-13 19:29:12 -08001088 struct pool_workqueue *pwq = get_work_pwq(work);
Tejun Heobf4ede02012-08-03 10:30:46 -07001089
1090 trace_workqueue_activate_work(work);
Tejun Heo112202d2013-02-13 19:29:12 -08001091 move_linked_works(work, &pwq->pool->worklist, NULL);
Tejun Heobf4ede02012-08-03 10:30:46 -07001092 __clear_bit(WORK_STRUCT_DELAYED_BIT, work_data_bits(work));
Tejun Heo112202d2013-02-13 19:29:12 -08001093 pwq->nr_active++;
Tejun Heobf4ede02012-08-03 10:30:46 -07001094}
1095
Tejun Heo112202d2013-02-13 19:29:12 -08001096static void pwq_activate_first_delayed(struct pool_workqueue *pwq)
Lai Jiangshan3aa62492012-09-18 10:40:00 -07001097{
Tejun Heo112202d2013-02-13 19:29:12 -08001098 struct work_struct *work = list_first_entry(&pwq->delayed_works,
Lai Jiangshan3aa62492012-09-18 10:40:00 -07001099 struct work_struct, entry);
1100
Tejun Heo112202d2013-02-13 19:29:12 -08001101 pwq_activate_delayed_work(work);
Lai Jiangshan3aa62492012-09-18 10:40:00 -07001102}
1103
Tejun Heobf4ede02012-08-03 10:30:46 -07001104/**
Tejun Heo112202d2013-02-13 19:29:12 -08001105 * pwq_dec_nr_in_flight - decrement pwq's nr_in_flight
1106 * @pwq: pwq of interest
Tejun Heobf4ede02012-08-03 10:30:46 -07001107 * @color: color of work which left the queue
Tejun Heobf4ede02012-08-03 10:30:46 -07001108 *
1109 * A work either has completed or is removed from pending queue,
Tejun Heo112202d2013-02-13 19:29:12 -08001110 * decrement nr_in_flight of its pwq and handle workqueue flushing.
Tejun Heobf4ede02012-08-03 10:30:46 -07001111 *
1112 * CONTEXT:
Tejun Heod565ed62013-01-24 11:01:33 -08001113 * spin_lock_irq(pool->lock).
Tejun Heobf4ede02012-08-03 10:30:46 -07001114 */
Tejun Heo112202d2013-02-13 19:29:12 -08001115static void pwq_dec_nr_in_flight(struct pool_workqueue *pwq, int color)
Tejun Heobf4ede02012-08-03 10:30:46 -07001116{
Tejun Heo8864b4e2013-03-12 11:30:04 -07001117 /* uncolored work items don't participate in flushing or nr_active */
Tejun Heobf4ede02012-08-03 10:30:46 -07001118 if (color == WORK_NO_COLOR)
Tejun Heo8864b4e2013-03-12 11:30:04 -07001119 goto out_put;
Tejun Heobf4ede02012-08-03 10:30:46 -07001120
Tejun Heo112202d2013-02-13 19:29:12 -08001121 pwq->nr_in_flight[color]--;
Tejun Heobf4ede02012-08-03 10:30:46 -07001122
Tejun Heo112202d2013-02-13 19:29:12 -08001123 pwq->nr_active--;
1124 if (!list_empty(&pwq->delayed_works)) {
Lai Jiangshanb3f9f402012-09-18 10:40:00 -07001125 /* one down, submit a delayed one */
Tejun Heo112202d2013-02-13 19:29:12 -08001126 if (pwq->nr_active < pwq->max_active)
1127 pwq_activate_first_delayed(pwq);
Tejun Heobf4ede02012-08-03 10:30:46 -07001128 }
1129
1130 /* is flush in progress and are we at the flushing tip? */
Tejun Heo112202d2013-02-13 19:29:12 -08001131 if (likely(pwq->flush_color != color))
Tejun Heo8864b4e2013-03-12 11:30:04 -07001132 goto out_put;
Tejun Heobf4ede02012-08-03 10:30:46 -07001133
1134 /* are there still in-flight works? */
Tejun Heo112202d2013-02-13 19:29:12 -08001135 if (pwq->nr_in_flight[color])
Tejun Heo8864b4e2013-03-12 11:30:04 -07001136 goto out_put;
Tejun Heobf4ede02012-08-03 10:30:46 -07001137
Tejun Heo112202d2013-02-13 19:29:12 -08001138 /* this pwq is done, clear flush_color */
1139 pwq->flush_color = -1;
Tejun Heobf4ede02012-08-03 10:30:46 -07001140
1141 /*
Tejun Heo112202d2013-02-13 19:29:12 -08001142 * If this was the last pwq, wake up the first flusher. It
Tejun Heobf4ede02012-08-03 10:30:46 -07001143 * will handle the rest.
1144 */
Tejun Heo112202d2013-02-13 19:29:12 -08001145 if (atomic_dec_and_test(&pwq->wq->nr_pwqs_to_flush))
1146 complete(&pwq->wq->first_flusher->done);
Tejun Heo8864b4e2013-03-12 11:30:04 -07001147out_put:
1148 put_pwq(pwq);
Tejun Heobf4ede02012-08-03 10:30:46 -07001149}
1150
Tejun Heo36e227d2012-08-03 10:30:46 -07001151/**
Tejun Heobbb68df2012-08-03 10:30:46 -07001152 * try_to_grab_pending - steal work item from worklist and disable irq
Tejun Heo36e227d2012-08-03 10:30:46 -07001153 * @work: work item to steal
1154 * @is_dwork: @work is a delayed_work
Tejun Heobbb68df2012-08-03 10:30:46 -07001155 * @flags: place to store irq state
Tejun Heo36e227d2012-08-03 10:30:46 -07001156 *
1157 * Try to grab PENDING bit of @work. This function can handle @work in any
Yacine Belkadid185af32013-07-31 14:59:24 -07001158 * stable state - idle, on timer or on worklist.
Tejun Heo36e227d2012-08-03 10:30:46 -07001159 *
Yacine Belkadid185af32013-07-31 14:59:24 -07001160 * Return:
Tejun Heo36e227d2012-08-03 10:30:46 -07001161 * 1 if @work was pending and we successfully stole PENDING
1162 * 0 if @work was idle and we claimed PENDING
1163 * -EAGAIN if PENDING couldn't be grabbed at the moment, safe to busy-retry
Tejun Heobbb68df2012-08-03 10:30:46 -07001164 * -ENOENT if someone else is canceling @work, this state may persist
1165 * for arbitrarily long
Tejun Heo36e227d2012-08-03 10:30:46 -07001166 *
Yacine Belkadid185af32013-07-31 14:59:24 -07001167 * Note:
Tejun Heobbb68df2012-08-03 10:30:46 -07001168 * On >= 0 return, the caller owns @work's PENDING bit. To avoid getting
Tejun Heoe0aecdd2012-08-21 13:18:24 -07001169 * interrupted while holding PENDING and @work off queue, irq must be
1170 * disabled on entry. This, combined with delayed_work->timer being
1171 * irqsafe, ensures that we return -EAGAIN for finite short period of time.
Tejun Heobbb68df2012-08-03 10:30:46 -07001172 *
1173 * On successful return, >= 0, irq is disabled and the caller is
1174 * responsible for releasing it using local_irq_restore(*@flags).
1175 *
Tejun Heoe0aecdd2012-08-21 13:18:24 -07001176 * This function is safe to call from any context including IRQ handler.
Tejun Heobf4ede02012-08-03 10:30:46 -07001177 */
Tejun Heobbb68df2012-08-03 10:30:46 -07001178static int try_to_grab_pending(struct work_struct *work, bool is_dwork,
1179 unsigned long *flags)
Tejun Heobf4ede02012-08-03 10:30:46 -07001180{
Tejun Heod565ed62013-01-24 11:01:33 -08001181 struct worker_pool *pool;
Tejun Heo112202d2013-02-13 19:29:12 -08001182 struct pool_workqueue *pwq;
Tejun Heobf4ede02012-08-03 10:30:46 -07001183
Tejun Heobbb68df2012-08-03 10:30:46 -07001184 local_irq_save(*flags);
1185
Tejun Heo36e227d2012-08-03 10:30:46 -07001186 /* try to steal the timer if it exists */
1187 if (is_dwork) {
1188 struct delayed_work *dwork = to_delayed_work(work);
1189
Tejun Heoe0aecdd2012-08-21 13:18:24 -07001190 /*
1191 * dwork->timer is irqsafe. If del_timer() fails, it's
1192 * guaranteed that the timer is not queued anywhere and not
1193 * running on the local CPU.
1194 */
Tejun Heo36e227d2012-08-03 10:30:46 -07001195 if (likely(del_timer(&dwork->timer)))
1196 return 1;
1197 }
1198
1199 /* try to claim PENDING the normal way */
Tejun Heobf4ede02012-08-03 10:30:46 -07001200 if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work)))
1201 return 0;
1202
1203 /*
1204 * The queueing is in progress, or it is already queued. Try to
1205 * steal it from ->worklist without clearing WORK_STRUCT_PENDING.
1206 */
Tejun Heod565ed62013-01-24 11:01:33 -08001207 pool = get_work_pool(work);
1208 if (!pool)
Tejun Heobbb68df2012-08-03 10:30:46 -07001209 goto fail;
Tejun Heobf4ede02012-08-03 10:30:46 -07001210
Tejun Heod565ed62013-01-24 11:01:33 -08001211 spin_lock(&pool->lock);
Lai Jiangshan0b3dae62013-02-06 18:04:53 -08001212 /*
Tejun Heo112202d2013-02-13 19:29:12 -08001213 * work->data is guaranteed to point to pwq only while the work
1214 * item is queued on pwq->wq, and both updating work->data to point
1215 * to pwq on queueing and to pool on dequeueing are done under
1216 * pwq->pool->lock. This in turn guarantees that, if work->data
1217 * points to pwq which is associated with a locked pool, the work
Lai Jiangshan0b3dae62013-02-06 18:04:53 -08001218 * item is currently queued on that pool.
1219 */
Tejun Heo112202d2013-02-13 19:29:12 -08001220 pwq = get_work_pwq(work);
1221 if (pwq && pwq->pool == pool) {
Tejun Heo16062832013-02-06 18:04:53 -08001222 debug_work_deactivate(work);
Lai Jiangshan3aa62492012-09-18 10:40:00 -07001223
Tejun Heo16062832013-02-06 18:04:53 -08001224 /*
1225 * A delayed work item cannot be grabbed directly because
1226 * it might have linked NO_COLOR work items which, if left
Tejun Heo112202d2013-02-13 19:29:12 -08001227 * on the delayed_list, will confuse pwq->nr_active
Tejun Heo16062832013-02-06 18:04:53 -08001228 * management later on and cause stall. Make sure the work
1229 * item is activated before grabbing.
1230 */
1231 if (*work_data_bits(work) & WORK_STRUCT_DELAYED)
Tejun Heo112202d2013-02-13 19:29:12 -08001232 pwq_activate_delayed_work(work);
Lai Jiangshan3aa62492012-09-18 10:40:00 -07001233
Tejun Heo16062832013-02-06 18:04:53 -08001234 list_del_init(&work->entry);
Tejun Heo112202d2013-02-13 19:29:12 -08001235 pwq_dec_nr_in_flight(get_work_pwq(work), get_work_color(work));
Tejun Heo36e227d2012-08-03 10:30:46 -07001236
Tejun Heo112202d2013-02-13 19:29:12 -08001237 /* work->data points to pwq iff queued, point to pool */
Tejun Heo16062832013-02-06 18:04:53 -08001238 set_work_pool_and_keep_pending(work, pool->id);
Lai Jiangshan4468a002013-02-06 18:04:53 -08001239
Tejun Heo16062832013-02-06 18:04:53 -08001240 spin_unlock(&pool->lock);
1241 return 1;
Tejun Heobf4ede02012-08-03 10:30:46 -07001242 }
Tejun Heod565ed62013-01-24 11:01:33 -08001243 spin_unlock(&pool->lock);
Tejun Heobbb68df2012-08-03 10:30:46 -07001244fail:
1245 local_irq_restore(*flags);
1246 if (work_is_canceling(work))
1247 return -ENOENT;
1248 cpu_relax();
Tejun Heo36e227d2012-08-03 10:30:46 -07001249 return -EAGAIN;
Tejun Heobf4ede02012-08-03 10:30:46 -07001250}
1251
1252/**
Tejun Heo706026c2013-01-24 11:01:34 -08001253 * insert_work - insert a work into a pool
Tejun Heo112202d2013-02-13 19:29:12 -08001254 * @pwq: pwq @work belongs to
Tejun Heo4690c4a2010-06-29 10:07:10 +02001255 * @work: work to insert
1256 * @head: insertion point
1257 * @extra_flags: extra WORK_STRUCT_* flags to set
1258 *
Tejun Heo112202d2013-02-13 19:29:12 -08001259 * Insert @work which belongs to @pwq after @head. @extra_flags is or'd to
Tejun Heo706026c2013-01-24 11:01:34 -08001260 * work_struct flags.
Tejun Heo4690c4a2010-06-29 10:07:10 +02001261 *
1262 * CONTEXT:
Tejun Heod565ed62013-01-24 11:01:33 -08001263 * spin_lock_irq(pool->lock).
Tejun Heo4690c4a2010-06-29 10:07:10 +02001264 */
Tejun Heo112202d2013-02-13 19:29:12 -08001265static void insert_work(struct pool_workqueue *pwq, struct work_struct *work,
1266 struct list_head *head, unsigned int extra_flags)
Oleg Nesterovb89deed2007-05-09 02:33:52 -07001267{
Tejun Heo112202d2013-02-13 19:29:12 -08001268 struct worker_pool *pool = pwq->pool;
Frederic Weisbeckere1d8aa92009-01-12 23:15:46 +01001269
Tejun Heo4690c4a2010-06-29 10:07:10 +02001270 /* we own @work, set data and link */
Tejun Heo112202d2013-02-13 19:29:12 -08001271 set_work_pwq(work, pwq, extra_flags);
Oleg Nesterov1a4d9b02008-07-25 01:47:47 -07001272 list_add_tail(&work->entry, head);
Tejun Heo8864b4e2013-03-12 11:30:04 -07001273 get_pwq(pwq);
Tejun Heoe22bee72010-06-29 10:07:14 +02001274
1275 /*
Tejun Heoc5aa87b2013-03-13 16:51:36 -07001276 * Ensure either wq_worker_sleeping() sees the above
1277 * list_add_tail() or we see zero nr_running to avoid workers lying
1278 * around lazily while there are works to be processed.
Tejun Heoe22bee72010-06-29 10:07:14 +02001279 */
1280 smp_mb();
1281
Tejun Heo63d95a92012-07-12 14:46:37 -07001282 if (__need_more_worker(pool))
1283 wake_up_worker(pool);
Oleg Nesterovb89deed2007-05-09 02:33:52 -07001284}
1285
Tejun Heoc8efcc22010-12-20 19:32:04 +01001286/*
1287 * Test whether @work is being queued from another work executing on the
Tejun Heo8d03ecf2013-02-13 19:29:10 -08001288 * same workqueue.
Tejun Heoc8efcc22010-12-20 19:32:04 +01001289 */
1290static bool is_chained_work(struct workqueue_struct *wq)
1291{
Tejun Heo8d03ecf2013-02-13 19:29:10 -08001292 struct worker *worker;
Tejun Heoc8efcc22010-12-20 19:32:04 +01001293
Tejun Heo8d03ecf2013-02-13 19:29:10 -08001294 worker = current_wq_worker();
1295 /*
1296 * Return %true iff I'm a worker execuing a work item on @wq. If
1297 * I'm @worker, it's safe to dereference it without locking.
1298 */
Tejun Heo112202d2013-02-13 19:29:12 -08001299 return worker && worker->current_pwq->wq == wq;
Tejun Heoc8efcc22010-12-20 19:32:04 +01001300}
1301
Tejun Heod84ff052013-03-12 11:29:59 -07001302static void __queue_work(int cpu, struct workqueue_struct *wq,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001303 struct work_struct *work)
1304{
Tejun Heo112202d2013-02-13 19:29:12 -08001305 struct pool_workqueue *pwq;
Tejun Heoc9178082013-03-12 11:30:04 -07001306 struct worker_pool *last_pool;
Tejun Heo1e19ffc2010-06-29 10:07:12 +02001307 struct list_head *worklist;
Tejun Heo8a2e8e5d2010-08-25 10:33:56 +02001308 unsigned int work_flags;
Joonsoo Kimb75cac92012-08-15 23:25:37 +09001309 unsigned int req_cpu = cpu;
Tejun Heo8930cab2012-08-03 10:30:45 -07001310
1311 /*
1312 * While a work item is PENDING && off queue, a task trying to
1313 * steal the PENDING will busy-loop waiting for it to either get
1314 * queued or lose PENDING. Grabbing PENDING and queueing should
1315 * happen with IRQ disabled.
1316 */
1317 WARN_ON_ONCE(!irqs_disabled());
Linus Torvalds1da177e2005-04-16 15:20:36 -07001318
Thomas Gleixnerdc186ad2009-11-16 01:09:48 +09001319 debug_work_activate(work);
Tejun Heo1e19ffc2010-06-29 10:07:12 +02001320
Li Bin9ef28a72013-09-09 13:13:58 +08001321 /* if draining, only works from the same workqueue are allowed */
Tejun Heo618b01e2013-03-12 11:30:04 -07001322 if (unlikely(wq->flags & __WQ_DRAINING) &&
Tejun Heoc8efcc22010-12-20 19:32:04 +01001323 WARN_ON_ONCE(!is_chained_work(wq)))
Tejun Heoe41e7042010-08-24 14:22:47 +02001324 return;
Tejun Heo9e8cd2f2013-03-12 11:30:04 -07001325retry:
Tejun Heodf2d5ae2013-04-01 11:23:35 -07001326 if (req_cpu == WORK_CPU_UNBOUND)
1327 cpu = raw_smp_processor_id();
1328
Tejun Heoc9178082013-03-12 11:30:04 -07001329 /* pwq which will be used unless @work is executing elsewhere */
Tejun Heodf2d5ae2013-04-01 11:23:35 -07001330 if (!(wq->flags & WQ_UNBOUND))
Tejun Heo7fb98ea2013-03-12 11:30:00 -07001331 pwq = per_cpu_ptr(wq->cpu_pwqs, cpu);
Tejun Heodf2d5ae2013-04-01 11:23:35 -07001332 else
1333 pwq = unbound_pwq_by_node(wq, cpu_to_node(cpu));
Tejun Heodbf25762012-08-20 14:51:23 -07001334
Tejun Heoc9178082013-03-12 11:30:04 -07001335 /*
1336 * If @work was previously on a different pool, it might still be
1337 * running there, in which case the work needs to be queued on that
1338 * pool to guarantee non-reentrancy.
1339 */
1340 last_pool = get_work_pool(work);
1341 if (last_pool && last_pool != pwq->pool) {
1342 struct worker *worker;
Tejun Heo18aa9ef2010-06-29 10:07:13 +02001343
Tejun Heoc9178082013-03-12 11:30:04 -07001344 spin_lock(&last_pool->lock);
Tejun Heo18aa9ef2010-06-29 10:07:13 +02001345
Tejun Heoc9178082013-03-12 11:30:04 -07001346 worker = find_worker_executing_work(last_pool, work);
Tejun Heo18aa9ef2010-06-29 10:07:13 +02001347
Tejun Heoc9178082013-03-12 11:30:04 -07001348 if (worker && worker->current_pwq->wq == wq) {
1349 pwq = worker->current_pwq;
Tejun Heo8930cab2012-08-03 10:30:45 -07001350 } else {
Tejun Heoc9178082013-03-12 11:30:04 -07001351 /* meh... not running there, queue here */
1352 spin_unlock(&last_pool->lock);
Tejun Heo112202d2013-02-13 19:29:12 -08001353 spin_lock(&pwq->pool->lock);
Tejun Heo8930cab2012-08-03 10:30:45 -07001354 }
Tejun Heof3421792010-07-02 10:03:51 +02001355 } else {
Tejun Heo112202d2013-02-13 19:29:12 -08001356 spin_lock(&pwq->pool->lock);
Tejun Heo502ca9d2010-06-29 10:07:13 +02001357 }
1358
Tejun Heo9e8cd2f2013-03-12 11:30:04 -07001359 /*
1360 * pwq is determined and locked. For unbound pools, we could have
1361 * raced with pwq release and it could already be dead. If its
1362 * refcnt is zero, repeat pwq selection. Note that pwqs never die
Tejun Heodf2d5ae2013-04-01 11:23:35 -07001363 * without another pwq replacing it in the numa_pwq_tbl or while
1364 * work items are executing on it, so the retrying is guaranteed to
Tejun Heo9e8cd2f2013-03-12 11:30:04 -07001365 * make forward-progress.
1366 */
1367 if (unlikely(!pwq->refcnt)) {
1368 if (wq->flags & WQ_UNBOUND) {
1369 spin_unlock(&pwq->pool->lock);
1370 cpu_relax();
1371 goto retry;
1372 }
1373 /* oops */
1374 WARN_ONCE(true, "workqueue: per-cpu pwq for %s on cpu%d has 0 refcnt",
1375 wq->name, cpu);
1376 }
1377
Tejun Heo112202d2013-02-13 19:29:12 -08001378 /* pwq determined, queue */
1379 trace_workqueue_queue_work(req_cpu, pwq, work);
Tejun Heo502ca9d2010-06-29 10:07:13 +02001380
Dan Carpenterf5b25522012-04-13 22:06:58 +03001381 if (WARN_ON(!list_empty(&work->entry))) {
Tejun Heo112202d2013-02-13 19:29:12 -08001382 spin_unlock(&pwq->pool->lock);
Dan Carpenterf5b25522012-04-13 22:06:58 +03001383 return;
1384 }
Tejun Heo1e19ffc2010-06-29 10:07:12 +02001385
Tejun Heo112202d2013-02-13 19:29:12 -08001386 pwq->nr_in_flight[pwq->work_color]++;
1387 work_flags = work_color_to_flags(pwq->work_color);
Tejun Heo1e19ffc2010-06-29 10:07:12 +02001388
Tejun Heo112202d2013-02-13 19:29:12 -08001389 if (likely(pwq->nr_active < pwq->max_active)) {
Tejun Heocdadf002010-10-05 10:49:55 +02001390 trace_workqueue_activate_work(work);
Tejun Heo112202d2013-02-13 19:29:12 -08001391 pwq->nr_active++;
1392 worklist = &pwq->pool->worklist;
Tejun Heo8a2e8e5d2010-08-25 10:33:56 +02001393 } else {
1394 work_flags |= WORK_STRUCT_DELAYED;
Tejun Heo112202d2013-02-13 19:29:12 -08001395 worklist = &pwq->delayed_works;
Tejun Heo8a2e8e5d2010-08-25 10:33:56 +02001396 }
Tejun Heo1e19ffc2010-06-29 10:07:12 +02001397
Tejun Heo112202d2013-02-13 19:29:12 -08001398 insert_work(pwq, work, worklist, work_flags);
Tejun Heo1e19ffc2010-06-29 10:07:12 +02001399
Tejun Heo112202d2013-02-13 19:29:12 -08001400 spin_unlock(&pwq->pool->lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001401}
1402
Rolf Eike Beer0fcb78c2006-07-30 03:03:42 -07001403/**
Zhang Ruic1a220e2008-07-23 21:28:39 -07001404 * queue_work_on - queue work on specific cpu
1405 * @cpu: CPU number to execute work on
1406 * @wq: workqueue to use
1407 * @work: work to queue
1408 *
Zhang Ruic1a220e2008-07-23 21:28:39 -07001409 * We queue the work to a specific CPU, the caller must ensure it
1410 * can't go away.
Yacine Belkadid185af32013-07-31 14:59:24 -07001411 *
1412 * Return: %false if @work was already on a queue, %true otherwise.
Zhang Ruic1a220e2008-07-23 21:28:39 -07001413 */
Tejun Heod4283e92012-08-03 10:30:44 -07001414bool queue_work_on(int cpu, struct workqueue_struct *wq,
1415 struct work_struct *work)
Zhang Ruic1a220e2008-07-23 21:28:39 -07001416{
Tejun Heod4283e92012-08-03 10:30:44 -07001417 bool ret = false;
Tejun Heo8930cab2012-08-03 10:30:45 -07001418 unsigned long flags;
1419
1420 local_irq_save(flags);
Zhang Ruic1a220e2008-07-23 21:28:39 -07001421
Tejun Heo22df02b2010-06-29 10:07:10 +02001422 if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) {
Tejun Heo4690c4a2010-06-29 10:07:10 +02001423 __queue_work(cpu, wq, work);
Tejun Heod4283e92012-08-03 10:30:44 -07001424 ret = true;
Zhang Ruic1a220e2008-07-23 21:28:39 -07001425 }
Tejun Heo8930cab2012-08-03 10:30:45 -07001426
1427 local_irq_restore(flags);
Zhang Ruic1a220e2008-07-23 21:28:39 -07001428 return ret;
1429}
Marc Dionnead7b1f82013-05-06 17:44:55 -04001430EXPORT_SYMBOL(queue_work_on);
Zhang Ruic1a220e2008-07-23 21:28:39 -07001431
Tejun Heod8e794d2012-08-03 10:30:45 -07001432void delayed_work_timer_fn(unsigned long __data)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001433{
David Howells52bad642006-11-22 14:54:01 +00001434 struct delayed_work *dwork = (struct delayed_work *)__data;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001435
Tejun Heoe0aecdd2012-08-21 13:18:24 -07001436 /* should have been called from irqsafe timer with irq already off */
Lai Jiangshan60c057b2013-02-06 18:04:53 -08001437 __queue_work(dwork->cpu, dwork->wq, &dwork->work);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001438}
Konstantin Khlebnikov1438ade52013-01-24 16:36:31 +04001439EXPORT_SYMBOL(delayed_work_timer_fn);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001440
Tejun Heo7beb2ed2012-08-03 10:30:46 -07001441static void __queue_delayed_work(int cpu, struct workqueue_struct *wq,
1442 struct delayed_work *dwork, unsigned long delay)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001443{
Tejun Heo7beb2ed2012-08-03 10:30:46 -07001444 struct timer_list *timer = &dwork->timer;
1445 struct work_struct *work = &dwork->work;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001446
Tejun Heo7beb2ed2012-08-03 10:30:46 -07001447 WARN_ON_ONCE(timer->function != delayed_work_timer_fn ||
1448 timer->data != (unsigned long)dwork);
Tejun Heofc4b5142012-12-04 07:40:39 -08001449 WARN_ON_ONCE(timer_pending(timer));
1450 WARN_ON_ONCE(!list_empty(&work->entry));
Tejun Heo7beb2ed2012-08-03 10:30:46 -07001451
Tejun Heo8852aac2012-12-01 16:23:42 -08001452 /*
1453 * If @delay is 0, queue @dwork->work immediately. This is for
1454 * both optimization and correctness. The earliest @timer can
1455 * expire is on the closest next tick and delayed_work users depend
1456 * on that there's no such delay when @delay is 0.
1457 */
1458 if (!delay) {
1459 __queue_work(cpu, wq, &dwork->work);
1460 return;
1461 }
1462
Tejun Heo7beb2ed2012-08-03 10:30:46 -07001463 timer_stats_timer_set_start_info(&dwork->timer);
1464
Lai Jiangshan60c057b2013-02-06 18:04:53 -08001465 dwork->wq = wq;
Tejun Heo12650572012-08-08 09:38:42 -07001466 dwork->cpu = cpu;
Tejun Heo7beb2ed2012-08-03 10:30:46 -07001467 timer->expires = jiffies + delay;
1468
1469 if (unlikely(cpu != WORK_CPU_UNBOUND))
1470 add_timer_on(timer, cpu);
1471 else
1472 add_timer(timer);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001473}
1474
Rolf Eike Beer0fcb78c2006-07-30 03:03:42 -07001475/**
1476 * queue_delayed_work_on - queue work on specific CPU after delay
1477 * @cpu: CPU number to execute work on
1478 * @wq: workqueue to use
Randy Dunlapaf9997e2006-12-22 01:06:52 -08001479 * @dwork: work to queue
Rolf Eike Beer0fcb78c2006-07-30 03:03:42 -07001480 * @delay: number of jiffies to wait before queueing
1481 *
Yacine Belkadid185af32013-07-31 14:59:24 -07001482 * Return: %false if @work was already on a queue, %true otherwise. If
Tejun Heo715f1302012-08-03 10:30:46 -07001483 * @delay is zero and @dwork is idle, it will be scheduled for immediate
1484 * execution.
Rolf Eike Beer0fcb78c2006-07-30 03:03:42 -07001485 */
Tejun Heod4283e92012-08-03 10:30:44 -07001486bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
1487 struct delayed_work *dwork, unsigned long delay)
Venkatesh Pallipadi7a6bc1c2006-06-28 13:50:33 -07001488{
David Howells52bad642006-11-22 14:54:01 +00001489 struct work_struct *work = &dwork->work;
Tejun Heod4283e92012-08-03 10:30:44 -07001490 bool ret = false;
Tejun Heo8930cab2012-08-03 10:30:45 -07001491 unsigned long flags;
1492
1493 /* read the comment in __queue_work() */
1494 local_irq_save(flags);
Venkatesh Pallipadi7a6bc1c2006-06-28 13:50:33 -07001495
Tejun Heo22df02b2010-06-29 10:07:10 +02001496 if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) {
Tejun Heo7beb2ed2012-08-03 10:30:46 -07001497 __queue_delayed_work(cpu, wq, dwork, delay);
Tejun Heod4283e92012-08-03 10:30:44 -07001498 ret = true;
Venkatesh Pallipadi7a6bc1c2006-06-28 13:50:33 -07001499 }
Tejun Heo8930cab2012-08-03 10:30:45 -07001500
1501 local_irq_restore(flags);
Venkatesh Pallipadi7a6bc1c2006-06-28 13:50:33 -07001502 return ret;
1503}
Marc Dionnead7b1f82013-05-06 17:44:55 -04001504EXPORT_SYMBOL(queue_delayed_work_on);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001505
Tejun Heoc8e55f32010-06-29 10:07:12 +02001506/**
Tejun Heo8376fe22012-08-03 10:30:47 -07001507 * mod_delayed_work_on - modify delay of or queue a delayed work on specific CPU
1508 * @cpu: CPU number to execute work on
1509 * @wq: workqueue to use
1510 * @dwork: work to queue
1511 * @delay: number of jiffies to wait before queueing
1512 *
1513 * If @dwork is idle, equivalent to queue_delayed_work_on(); otherwise,
1514 * modify @dwork's timer so that it expires after @delay. If @delay is
1515 * zero, @work is guaranteed to be scheduled immediately regardless of its
1516 * current state.
1517 *
Yacine Belkadid185af32013-07-31 14:59:24 -07001518 * Return: %false if @dwork was idle and queued, %true if @dwork was
Tejun Heo8376fe22012-08-03 10:30:47 -07001519 * pending and its timer was modified.
1520 *
Tejun Heoe0aecdd2012-08-21 13:18:24 -07001521 * This function is safe to call from any context including IRQ handler.
Tejun Heo8376fe22012-08-03 10:30:47 -07001522 * See try_to_grab_pending() for details.
1523 */
1524bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq,
1525 struct delayed_work *dwork, unsigned long delay)
1526{
1527 unsigned long flags;
1528 int ret;
1529
1530 do {
1531 ret = try_to_grab_pending(&dwork->work, true, &flags);
1532 } while (unlikely(ret == -EAGAIN));
1533
1534 if (likely(ret >= 0)) {
1535 __queue_delayed_work(cpu, wq, dwork, delay);
1536 local_irq_restore(flags);
1537 }
1538
1539 /* -ENOENT from try_to_grab_pending() becomes %true */
1540 return ret;
1541}
1542EXPORT_SYMBOL_GPL(mod_delayed_work_on);
1543
1544/**
Tejun Heoc8e55f32010-06-29 10:07:12 +02001545 * worker_enter_idle - enter idle state
1546 * @worker: worker which is entering idle state
1547 *
1548 * @worker is entering idle state. Update stats and idle timer if
1549 * necessary.
1550 *
1551 * LOCKING:
Tejun Heod565ed62013-01-24 11:01:33 -08001552 * spin_lock_irq(pool->lock).
Tejun Heoc8e55f32010-06-29 10:07:12 +02001553 */
1554static void worker_enter_idle(struct worker *worker)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001555{
Tejun Heobd7bdd42012-07-12 14:46:37 -07001556 struct worker_pool *pool = worker->pool;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001557
Tejun Heo6183c002013-03-12 11:29:57 -07001558 if (WARN_ON_ONCE(worker->flags & WORKER_IDLE) ||
1559 WARN_ON_ONCE(!list_empty(&worker->entry) &&
1560 (worker->hentry.next || worker->hentry.pprev)))
1561 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001562
Tejun Heocb444762010-07-02 10:03:50 +02001563 /* can't use worker_set_flags(), also called from start_worker() */
1564 worker->flags |= WORKER_IDLE;
Tejun Heobd7bdd42012-07-12 14:46:37 -07001565 pool->nr_idle++;
Tejun Heoe22bee72010-06-29 10:07:14 +02001566 worker->last_active = jiffies;
Peter Zijlstrad5abe662006-12-06 20:37:26 -08001567
Tejun Heoc8e55f32010-06-29 10:07:12 +02001568 /* idle_list is LIFO */
Tejun Heobd7bdd42012-07-12 14:46:37 -07001569 list_add(&worker->entry, &pool->idle_list);
Tejun Heodb7bccf2010-06-29 10:07:12 +02001570
Tejun Heo628c78e2012-07-17 12:39:27 -07001571 if (too_many_workers(pool) && !timer_pending(&pool->idle_timer))
1572 mod_timer(&pool->idle_timer, jiffies + IDLE_WORKER_TIMEOUT);
Tejun Heocb444762010-07-02 10:03:50 +02001573
Tejun Heo544ecf32012-05-14 15:04:50 -07001574 /*
Tejun Heo706026c2013-01-24 11:01:34 -08001575 * Sanity check nr_running. Because wq_unbind_fn() releases
Tejun Heod565ed62013-01-24 11:01:33 -08001576 * pool->lock between setting %WORKER_UNBOUND and zapping
Tejun Heo628c78e2012-07-17 12:39:27 -07001577 * nr_running, the warning may trigger spuriously. Check iff
1578 * unbind is not in progress.
Tejun Heo544ecf32012-05-14 15:04:50 -07001579 */
Tejun Heo24647572013-01-24 11:01:33 -08001580 WARN_ON_ONCE(!(pool->flags & POOL_DISASSOCIATED) &&
Tejun Heobd7bdd42012-07-12 14:46:37 -07001581 pool->nr_workers == pool->nr_idle &&
Tejun Heoe19e3972013-01-24 11:39:44 -08001582 atomic_read(&pool->nr_running));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001583}
1584
Tejun Heoc8e55f32010-06-29 10:07:12 +02001585/**
1586 * worker_leave_idle - leave idle state
1587 * @worker: worker which is leaving idle state
1588 *
1589 * @worker is leaving idle state. Update stats.
1590 *
1591 * LOCKING:
Tejun Heod565ed62013-01-24 11:01:33 -08001592 * spin_lock_irq(pool->lock).
Tejun Heoc8e55f32010-06-29 10:07:12 +02001593 */
1594static void worker_leave_idle(struct worker *worker)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001595{
Tejun Heobd7bdd42012-07-12 14:46:37 -07001596 struct worker_pool *pool = worker->pool;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001597
Tejun Heo6183c002013-03-12 11:29:57 -07001598 if (WARN_ON_ONCE(!(worker->flags & WORKER_IDLE)))
1599 return;
Tejun Heod302f012010-06-29 10:07:13 +02001600 worker_clr_flags(worker, WORKER_IDLE);
Tejun Heobd7bdd42012-07-12 14:46:37 -07001601 pool->nr_idle--;
Tejun Heoc8e55f32010-06-29 10:07:12 +02001602 list_del_init(&worker->entry);
1603}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001604
Tejun Heoe22bee72010-06-29 10:07:14 +02001605/**
Lai Jiangshanf36dc672013-02-19 12:17:02 -08001606 * worker_maybe_bind_and_lock - try to bind %current to worker_pool and lock it
1607 * @pool: target worker_pool
1608 *
1609 * Bind %current to the cpu of @pool if it is associated and lock @pool.
Tejun Heoe22bee72010-06-29 10:07:14 +02001610 *
1611 * Works which are scheduled while the cpu is online must at least be
1612 * scheduled to a worker which is bound to the cpu so that if they are
1613 * flushed from cpu callbacks while cpu is going down, they are
1614 * guaranteed to execute on the cpu.
1615 *
Lai Jiangshanf5faa072013-02-19 12:17:02 -08001616 * This function is to be used by unbound workers and rescuers to bind
Tejun Heoe22bee72010-06-29 10:07:14 +02001617 * themselves to the target cpu and may race with cpu going down or
1618 * coming online. kthread_bind() can't be used because it may put the
1619 * worker to already dead cpu and set_cpus_allowed_ptr() can't be used
Tejun Heo706026c2013-01-24 11:01:34 -08001620 * verbatim as it's best effort and blocking and pool may be
Tejun Heoe22bee72010-06-29 10:07:14 +02001621 * [dis]associated in the meantime.
1622 *
Tejun Heo706026c2013-01-24 11:01:34 -08001623 * This function tries set_cpus_allowed() and locks pool and verifies the
Tejun Heo24647572013-01-24 11:01:33 -08001624 * binding against %POOL_DISASSOCIATED which is set during
Tejun Heof2d5a0e2012-07-17 12:39:26 -07001625 * %CPU_DOWN_PREPARE and cleared during %CPU_ONLINE, so if the worker
1626 * enters idle state or fetches works without dropping lock, it can
1627 * guarantee the scheduling requirement described in the first paragraph.
Tejun Heoe22bee72010-06-29 10:07:14 +02001628 *
1629 * CONTEXT:
Tejun Heod565ed62013-01-24 11:01:33 -08001630 * Might sleep. Called without any lock but returns with pool->lock
Tejun Heoe22bee72010-06-29 10:07:14 +02001631 * held.
1632 *
Yacine Belkadid185af32013-07-31 14:59:24 -07001633 * Return:
Tejun Heo706026c2013-01-24 11:01:34 -08001634 * %true if the associated pool is online (@worker is successfully
Tejun Heoe22bee72010-06-29 10:07:14 +02001635 * bound), %false if offline.
1636 */
Lai Jiangshanf36dc672013-02-19 12:17:02 -08001637static bool worker_maybe_bind_and_lock(struct worker_pool *pool)
Tejun Heod565ed62013-01-24 11:01:33 -08001638__acquires(&pool->lock)
Tejun Heoe22bee72010-06-29 10:07:14 +02001639{
Tejun Heoe22bee72010-06-29 10:07:14 +02001640 while (true) {
1641 /*
1642 * The following call may fail, succeed or succeed
1643 * without actually migrating the task to the cpu if
1644 * it races with cpu hotunplug operation. Verify
Tejun Heo24647572013-01-24 11:01:33 -08001645 * against POOL_DISASSOCIATED.
Tejun Heoe22bee72010-06-29 10:07:14 +02001646 */
Tejun Heo24647572013-01-24 11:01:33 -08001647 if (!(pool->flags & POOL_DISASSOCIATED))
Tejun Heo7a4e3442013-03-12 11:30:00 -07001648 set_cpus_allowed_ptr(current, pool->attrs->cpumask);
Oleg Nesterov85f41862007-05-09 02:34:20 -07001649
Tejun Heod565ed62013-01-24 11:01:33 -08001650 spin_lock_irq(&pool->lock);
Tejun Heo24647572013-01-24 11:01:33 -08001651 if (pool->flags & POOL_DISASSOCIATED)
Tejun Heoe22bee72010-06-29 10:07:14 +02001652 return false;
Lai Jiangshanf5faa072013-02-19 12:17:02 -08001653 if (task_cpu(current) == pool->cpu &&
Tejun Heo7a4e3442013-03-12 11:30:00 -07001654 cpumask_equal(&current->cpus_allowed, pool->attrs->cpumask))
Tejun Heoe22bee72010-06-29 10:07:14 +02001655 return true;
Tejun Heod565ed62013-01-24 11:01:33 -08001656 spin_unlock_irq(&pool->lock);
Oleg Nesterov3af244332007-05-09 02:34:09 -07001657
Tejun Heo5035b202011-04-29 18:08:37 +02001658 /*
1659 * We've raced with CPU hot[un]plug. Give it a breather
1660 * and retry migration. cond_resched() is required here;
1661 * otherwise, we might deadlock against cpu_stop trying to
1662 * bring down the CPU on non-preemptive kernel.
1663 */
Tejun Heoe22bee72010-06-29 10:07:14 +02001664 cpu_relax();
Tejun Heo5035b202011-04-29 18:08:37 +02001665 cond_resched();
Tejun Heoe22bee72010-06-29 10:07:14 +02001666 }
1667}
1668
Tejun Heoc34056a2010-06-29 10:07:11 +02001669static struct worker *alloc_worker(void)
1670{
1671 struct worker *worker;
1672
1673 worker = kzalloc(sizeof(*worker), GFP_KERNEL);
Tejun Heoc8e55f32010-06-29 10:07:12 +02001674 if (worker) {
1675 INIT_LIST_HEAD(&worker->entry);
Tejun Heoaffee4b2010-06-29 10:07:12 +02001676 INIT_LIST_HEAD(&worker->scheduled);
Lai Jiangshanda028462014-05-20 17:46:31 +08001677 INIT_LIST_HEAD(&worker->node);
Tejun Heoe22bee72010-06-29 10:07:14 +02001678 /* on creation a worker is in !idle && prep state */
1679 worker->flags = WORKER_PREP;
Tejun Heoc8e55f32010-06-29 10:07:12 +02001680 }
Tejun Heoc34056a2010-06-29 10:07:11 +02001681 return worker;
1682}
1683
1684/**
Lai Jiangshan60f5a4b2014-05-20 17:46:29 +08001685 * worker_detach_from_pool() - detach a worker from its pool
1686 * @worker: worker which is attached to its pool
1687 * @pool: the pool @worker is attached to
1688 *
1689 * Undo the attaching which had been done in create_worker(). The caller
1690 * worker shouldn't access to the pool after detached except it has other
1691 * reference to the pool.
1692 */
1693static void worker_detach_from_pool(struct worker *worker,
1694 struct worker_pool *pool)
1695{
1696 struct completion *detach_completion = NULL;
1697
1698 mutex_lock(&pool->manager_mutex);
1699 idr_remove(&pool->worker_idr, worker->id);
Lai Jiangshanda028462014-05-20 17:46:31 +08001700 list_del(&worker->node);
1701 if (list_empty(&pool->workers))
Lai Jiangshan60f5a4b2014-05-20 17:46:29 +08001702 detach_completion = pool->detach_completion;
1703 mutex_unlock(&pool->manager_mutex);
1704
1705 if (detach_completion)
1706 complete(detach_completion);
1707}
1708
1709/**
Tejun Heoc34056a2010-06-29 10:07:11 +02001710 * create_worker - create a new workqueue worker
Tejun Heo63d95a92012-07-12 14:46:37 -07001711 * @pool: pool the new worker will belong to
Tejun Heoc34056a2010-06-29 10:07:11 +02001712 *
Lai Jiangshan73eb7fe2014-05-20 17:46:28 +08001713 * Create a new worker which is attached to @pool. The new worker must be
1714 * started by start_worker().
Tejun Heoc34056a2010-06-29 10:07:11 +02001715 *
1716 * CONTEXT:
1717 * Might sleep. Does GFP_KERNEL allocations.
1718 *
Yacine Belkadid185af32013-07-31 14:59:24 -07001719 * Return:
Tejun Heoc34056a2010-06-29 10:07:11 +02001720 * Pointer to the newly created worker.
1721 */
Tejun Heobc2ae0f2012-07-17 12:39:27 -07001722static struct worker *create_worker(struct worker_pool *pool)
Tejun Heoc34056a2010-06-29 10:07:11 +02001723{
Tejun Heoc34056a2010-06-29 10:07:11 +02001724 struct worker *worker = NULL;
Tejun Heof3421792010-07-02 10:03:51 +02001725 int id = -1;
Tejun Heoe3c916a2013-04-01 11:23:32 -07001726 char id_buf[16];
Tejun Heoc34056a2010-06-29 10:07:11 +02001727
Tejun Heocd549682013-03-13 19:47:39 -07001728 lockdep_assert_held(&pool->manager_mutex);
1729
Tejun Heo822d8402013-03-19 13:45:21 -07001730 /*
1731 * ID is needed to determine kthread name. Allocate ID first
1732 * without installing the pointer.
1733 */
Lai Jiangshan9625ab12014-05-20 17:46:27 +08001734 id = idr_alloc(&pool->worker_idr, NULL, 0, 0, GFP_KERNEL);
Tejun Heo822d8402013-03-19 13:45:21 -07001735 if (id < 0)
1736 goto fail;
Tejun Heoc34056a2010-06-29 10:07:11 +02001737
1738 worker = alloc_worker();
1739 if (!worker)
1740 goto fail;
1741
Tejun Heobd7bdd42012-07-12 14:46:37 -07001742 worker->pool = pool;
Tejun Heoc34056a2010-06-29 10:07:11 +02001743 worker->id = id;
1744
Tejun Heo29c91e92013-03-12 11:30:03 -07001745 if (pool->cpu >= 0)
Tejun Heoe3c916a2013-04-01 11:23:32 -07001746 snprintf(id_buf, sizeof(id_buf), "%d:%d%s", pool->cpu, id,
1747 pool->attrs->nice < 0 ? "H" : "");
Tejun Heof3421792010-07-02 10:03:51 +02001748 else
Tejun Heoe3c916a2013-04-01 11:23:32 -07001749 snprintf(id_buf, sizeof(id_buf), "u%d:%d", pool->id, id);
1750
Tejun Heof3f90ad2013-04-01 11:23:34 -07001751 worker->task = kthread_create_on_node(worker_thread, worker, pool->node,
Tejun Heoe3c916a2013-04-01 11:23:32 -07001752 "kworker/%s", id_buf);
Tejun Heoc34056a2010-06-29 10:07:11 +02001753 if (IS_ERR(worker->task))
1754 goto fail;
1755
Oleg Nesterov91151222013-11-14 12:56:18 +01001756 set_user_nice(worker->task, pool->attrs->nice);
1757
1758 /* prevent userland from meddling with cpumask of workqueue workers */
1759 worker->task->flags |= PF_NO_SETAFFINITY;
1760
Tejun Heoc5aa87b2013-03-13 16:51:36 -07001761 /*
1762 * set_cpus_allowed_ptr() will fail if the cpumask doesn't have any
1763 * online CPUs. It'll be re-applied when any of the CPUs come up.
1764 */
Tejun Heo7a4e3442013-03-12 11:30:00 -07001765 set_cpus_allowed_ptr(worker->task, pool->attrs->cpumask);
Tejun Heo32704762012-07-13 22:16:45 -07001766
Tejun Heo7a4e3442013-03-12 11:30:00 -07001767 /*
1768 * The caller is responsible for ensuring %POOL_DISASSOCIATED
1769 * remains stable across this function. See the comments above the
1770 * flag definition for details.
1771 */
1772 if (pool->flags & POOL_DISASSOCIATED)
Tejun Heobc2ae0f2012-07-17 12:39:27 -07001773 worker->flags |= WORKER_UNBOUND;
Oleg Nesterov3af244332007-05-09 02:34:09 -07001774
Tejun Heo822d8402013-03-19 13:45:21 -07001775 /* successful, commit the pointer to idr */
Tejun Heo822d8402013-03-19 13:45:21 -07001776 idr_replace(&pool->worker_idr, worker, worker->id);
Lai Jiangshanda028462014-05-20 17:46:31 +08001777 /* successful, attach the worker to the pool */
1778 list_add_tail(&worker->node, &pool->workers);
Tejun Heo822d8402013-03-19 13:45:21 -07001779
Tejun Heoc34056a2010-06-29 10:07:11 +02001780 return worker;
Tejun Heo822d8402013-03-19 13:45:21 -07001781
Tejun Heoc34056a2010-06-29 10:07:11 +02001782fail:
Lai Jiangshan9625ab12014-05-20 17:46:27 +08001783 if (id >= 0)
Tejun Heo822d8402013-03-19 13:45:21 -07001784 idr_remove(&pool->worker_idr, id);
Tejun Heoc34056a2010-06-29 10:07:11 +02001785 kfree(worker);
1786 return NULL;
1787}
1788
1789/**
1790 * start_worker - start a newly created worker
1791 * @worker: worker to start
1792 *
Tejun Heo706026c2013-01-24 11:01:34 -08001793 * Make the pool aware of @worker and start it.
Tejun Heoc34056a2010-06-29 10:07:11 +02001794 *
1795 * CONTEXT:
Tejun Heod565ed62013-01-24 11:01:33 -08001796 * spin_lock_irq(pool->lock).
Tejun Heoc34056a2010-06-29 10:07:11 +02001797 */
1798static void start_worker(struct worker *worker)
1799{
Tejun Heobd7bdd42012-07-12 14:46:37 -07001800 worker->pool->nr_workers++;
Tejun Heoc8e55f32010-06-29 10:07:12 +02001801 worker_enter_idle(worker);
Tejun Heoc34056a2010-06-29 10:07:11 +02001802 wake_up_process(worker->task);
1803}
1804
1805/**
Tejun Heoebf44d12013-03-13 19:47:39 -07001806 * create_and_start_worker - create and start a worker for a pool
1807 * @pool: the target pool
1808 *
Tejun Heocd549682013-03-13 19:47:39 -07001809 * Grab the managership of @pool and create and start a new worker for it.
Yacine Belkadid185af32013-07-31 14:59:24 -07001810 *
1811 * Return: 0 on success. A negative error code otherwise.
Tejun Heoebf44d12013-03-13 19:47:39 -07001812 */
1813static int create_and_start_worker(struct worker_pool *pool)
1814{
1815 struct worker *worker;
1816
Tejun Heocd549682013-03-13 19:47:39 -07001817 mutex_lock(&pool->manager_mutex);
1818
Tejun Heoebf44d12013-03-13 19:47:39 -07001819 worker = create_worker(pool);
1820 if (worker) {
1821 spin_lock_irq(&pool->lock);
1822 start_worker(worker);
1823 spin_unlock_irq(&pool->lock);
1824 }
1825
Tejun Heocd549682013-03-13 19:47:39 -07001826 mutex_unlock(&pool->manager_mutex);
1827
Tejun Heoebf44d12013-03-13 19:47:39 -07001828 return worker ? 0 : -ENOMEM;
1829}
1830
1831/**
Tejun Heoc34056a2010-06-29 10:07:11 +02001832 * destroy_worker - destroy a workqueue worker
1833 * @worker: worker to be destroyed
1834 *
Lai Jiangshan73eb7fe2014-05-20 17:46:28 +08001835 * Destroy @worker and adjust @pool stats accordingly. The worker should
1836 * be idle.
Tejun Heoc8e55f32010-06-29 10:07:12 +02001837 *
1838 * CONTEXT:
Lai Jiangshan60f5a4b2014-05-20 17:46:29 +08001839 * spin_lock_irq(pool->lock).
Tejun Heoc34056a2010-06-29 10:07:11 +02001840 */
1841static void destroy_worker(struct worker *worker)
1842{
Tejun Heobd7bdd42012-07-12 14:46:37 -07001843 struct worker_pool *pool = worker->pool;
Tejun Heoc34056a2010-06-29 10:07:11 +02001844
Tejun Heocd549682013-03-13 19:47:39 -07001845 lockdep_assert_held(&pool->lock);
1846
Tejun Heoc34056a2010-06-29 10:07:11 +02001847 /* sanity check frenzy */
Tejun Heo6183c002013-03-12 11:29:57 -07001848 if (WARN_ON(worker->current_work) ||
Lai Jiangshan73eb7fe2014-05-20 17:46:28 +08001849 WARN_ON(!list_empty(&worker->scheduled)) ||
1850 WARN_ON(!(worker->flags & WORKER_IDLE)))
Tejun Heo6183c002013-03-12 11:29:57 -07001851 return;
Tejun Heoc34056a2010-06-29 10:07:11 +02001852
Lai Jiangshan73eb7fe2014-05-20 17:46:28 +08001853 pool->nr_workers--;
1854 pool->nr_idle--;
Tejun Heoc8e55f32010-06-29 10:07:12 +02001855
1856 list_del_init(&worker->entry);
Tejun Heocb444762010-07-02 10:03:50 +02001857 worker->flags |= WORKER_DIE;
Lai Jiangshan60f5a4b2014-05-20 17:46:29 +08001858 wake_up_process(worker->task);
Tejun Heoc34056a2010-06-29 10:07:11 +02001859}
1860
Tejun Heo63d95a92012-07-12 14:46:37 -07001861static void idle_worker_timeout(unsigned long __pool)
Tejun Heoe22bee72010-06-29 10:07:14 +02001862{
Tejun Heo63d95a92012-07-12 14:46:37 -07001863 struct worker_pool *pool = (void *)__pool;
Tejun Heoe22bee72010-06-29 10:07:14 +02001864
Tejun Heod565ed62013-01-24 11:01:33 -08001865 spin_lock_irq(&pool->lock);
Tejun Heoe22bee72010-06-29 10:07:14 +02001866
Lai Jiangshan3347fc92014-05-20 17:46:30 +08001867 while (too_many_workers(pool)) {
Tejun Heoe22bee72010-06-29 10:07:14 +02001868 struct worker *worker;
1869 unsigned long expires;
1870
1871 /* idle_list is kept in LIFO order, check the last one */
Tejun Heo63d95a92012-07-12 14:46:37 -07001872 worker = list_entry(pool->idle_list.prev, struct worker, entry);
Tejun Heoe22bee72010-06-29 10:07:14 +02001873 expires = worker->last_active + IDLE_WORKER_TIMEOUT;
1874
Lai Jiangshan3347fc92014-05-20 17:46:30 +08001875 if (time_before(jiffies, expires)) {
Tejun Heo63d95a92012-07-12 14:46:37 -07001876 mod_timer(&pool->idle_timer, expires);
Lai Jiangshan3347fc92014-05-20 17:46:30 +08001877 break;
Tejun Heoe22bee72010-06-29 10:07:14 +02001878 }
Lai Jiangshan3347fc92014-05-20 17:46:30 +08001879
1880 destroy_worker(worker);
Tejun Heoe22bee72010-06-29 10:07:14 +02001881 }
1882
Tejun Heod565ed62013-01-24 11:01:33 -08001883 spin_unlock_irq(&pool->lock);
Tejun Heoe22bee72010-06-29 10:07:14 +02001884}
1885
Tejun Heo493a1722013-03-12 11:29:59 -07001886static void send_mayday(struct work_struct *work)
Tejun Heoe22bee72010-06-29 10:07:14 +02001887{
Tejun Heo112202d2013-02-13 19:29:12 -08001888 struct pool_workqueue *pwq = get_work_pwq(work);
1889 struct workqueue_struct *wq = pwq->wq;
Tejun Heo493a1722013-03-12 11:29:59 -07001890
Tejun Heo2e109a22013-03-13 19:47:40 -07001891 lockdep_assert_held(&wq_mayday_lock);
Tejun Heoe22bee72010-06-29 10:07:14 +02001892
Tejun Heo493008a2013-03-12 11:30:03 -07001893 if (!wq->rescuer)
Tejun Heo493a1722013-03-12 11:29:59 -07001894 return;
Tejun Heoe22bee72010-06-29 10:07:14 +02001895
1896 /* mayday mayday mayday */
Tejun Heo493a1722013-03-12 11:29:59 -07001897 if (list_empty(&pwq->mayday_node)) {
Lai Jiangshan77668c82014-04-18 11:04:16 -04001898 /*
1899 * If @pwq is for an unbound wq, its base ref may be put at
1900 * any time due to an attribute change. Pin @pwq until the
1901 * rescuer is done with it.
1902 */
1903 get_pwq(pwq);
Tejun Heo493a1722013-03-12 11:29:59 -07001904 list_add_tail(&pwq->mayday_node, &wq->maydays);
Tejun Heoe22bee72010-06-29 10:07:14 +02001905 wake_up_process(wq->rescuer->task);
Tejun Heo493a1722013-03-12 11:29:59 -07001906 }
Tejun Heoe22bee72010-06-29 10:07:14 +02001907}
1908
Tejun Heo706026c2013-01-24 11:01:34 -08001909static void pool_mayday_timeout(unsigned long __pool)
Tejun Heoe22bee72010-06-29 10:07:14 +02001910{
Tejun Heo63d95a92012-07-12 14:46:37 -07001911 struct worker_pool *pool = (void *)__pool;
Tejun Heoe22bee72010-06-29 10:07:14 +02001912 struct work_struct *work;
1913
Tejun Heo2e109a22013-03-13 19:47:40 -07001914 spin_lock_irq(&wq_mayday_lock); /* for wq->maydays */
Tejun Heo493a1722013-03-12 11:29:59 -07001915 spin_lock(&pool->lock);
Tejun Heoe22bee72010-06-29 10:07:14 +02001916
Tejun Heo63d95a92012-07-12 14:46:37 -07001917 if (need_to_create_worker(pool)) {
Tejun Heoe22bee72010-06-29 10:07:14 +02001918 /*
1919 * We've been trying to create a new worker but
1920 * haven't been successful. We might be hitting an
1921 * allocation deadlock. Send distress signals to
1922 * rescuers.
1923 */
Tejun Heo63d95a92012-07-12 14:46:37 -07001924 list_for_each_entry(work, &pool->worklist, entry)
Tejun Heoe22bee72010-06-29 10:07:14 +02001925 send_mayday(work);
1926 }
1927
Tejun Heo493a1722013-03-12 11:29:59 -07001928 spin_unlock(&pool->lock);
Tejun Heo2e109a22013-03-13 19:47:40 -07001929 spin_unlock_irq(&wq_mayday_lock);
Tejun Heoe22bee72010-06-29 10:07:14 +02001930
Tejun Heo63d95a92012-07-12 14:46:37 -07001931 mod_timer(&pool->mayday_timer, jiffies + MAYDAY_INTERVAL);
Tejun Heoe22bee72010-06-29 10:07:14 +02001932}
1933
1934/**
1935 * maybe_create_worker - create a new worker if necessary
Tejun Heo63d95a92012-07-12 14:46:37 -07001936 * @pool: pool to create a new worker for
Tejun Heoe22bee72010-06-29 10:07:14 +02001937 *
Tejun Heo63d95a92012-07-12 14:46:37 -07001938 * Create a new worker for @pool if necessary. @pool is guaranteed to
Tejun Heoe22bee72010-06-29 10:07:14 +02001939 * have at least one idle worker on return from this function. If
1940 * creating a new worker takes longer than MAYDAY_INTERVAL, mayday is
Tejun Heo63d95a92012-07-12 14:46:37 -07001941 * sent to all rescuers with works scheduled on @pool to resolve
Tejun Heoe22bee72010-06-29 10:07:14 +02001942 * possible allocation deadlock.
1943 *
Tejun Heoc5aa87b2013-03-13 16:51:36 -07001944 * On return, need_to_create_worker() is guaranteed to be %false and
1945 * may_start_working() %true.
Tejun Heoe22bee72010-06-29 10:07:14 +02001946 *
1947 * LOCKING:
Tejun Heod565ed62013-01-24 11:01:33 -08001948 * spin_lock_irq(pool->lock) which may be released and regrabbed
Tejun Heoe22bee72010-06-29 10:07:14 +02001949 * multiple times. Does GFP_KERNEL allocations. Called only from
1950 * manager.
1951 *
Yacine Belkadid185af32013-07-31 14:59:24 -07001952 * Return:
Tejun Heoc5aa87b2013-03-13 16:51:36 -07001953 * %false if no action was taken and pool->lock stayed locked, %true
Tejun Heoe22bee72010-06-29 10:07:14 +02001954 * otherwise.
1955 */
Tejun Heo63d95a92012-07-12 14:46:37 -07001956static bool maybe_create_worker(struct worker_pool *pool)
Tejun Heod565ed62013-01-24 11:01:33 -08001957__releases(&pool->lock)
1958__acquires(&pool->lock)
Tejun Heoe22bee72010-06-29 10:07:14 +02001959{
Tejun Heo63d95a92012-07-12 14:46:37 -07001960 if (!need_to_create_worker(pool))
Tejun Heoe22bee72010-06-29 10:07:14 +02001961 return false;
1962restart:
Tejun Heod565ed62013-01-24 11:01:33 -08001963 spin_unlock_irq(&pool->lock);
Tejun Heo9f9c2362010-07-14 11:31:20 +02001964
Tejun Heoe22bee72010-06-29 10:07:14 +02001965 /* if we don't make progress in MAYDAY_INITIAL_TIMEOUT, call for help */
Tejun Heo63d95a92012-07-12 14:46:37 -07001966 mod_timer(&pool->mayday_timer, jiffies + MAYDAY_INITIAL_TIMEOUT);
Tejun Heoe22bee72010-06-29 10:07:14 +02001967
1968 while (true) {
1969 struct worker *worker;
1970
Tejun Heobc2ae0f2012-07-17 12:39:27 -07001971 worker = create_worker(pool);
Tejun Heoe22bee72010-06-29 10:07:14 +02001972 if (worker) {
Tejun Heo63d95a92012-07-12 14:46:37 -07001973 del_timer_sync(&pool->mayday_timer);
Tejun Heod565ed62013-01-24 11:01:33 -08001974 spin_lock_irq(&pool->lock);
Tejun Heoe22bee72010-06-29 10:07:14 +02001975 start_worker(worker);
Tejun Heo6183c002013-03-12 11:29:57 -07001976 if (WARN_ON_ONCE(need_to_create_worker(pool)))
1977 goto restart;
Tejun Heoe22bee72010-06-29 10:07:14 +02001978 return true;
1979 }
1980
Tejun Heo63d95a92012-07-12 14:46:37 -07001981 if (!need_to_create_worker(pool))
Tejun Heoe22bee72010-06-29 10:07:14 +02001982 break;
1983
Tejun Heoe22bee72010-06-29 10:07:14 +02001984 __set_current_state(TASK_INTERRUPTIBLE);
1985 schedule_timeout(CREATE_COOLDOWN);
Tejun Heo9f9c2362010-07-14 11:31:20 +02001986
Tejun Heo63d95a92012-07-12 14:46:37 -07001987 if (!need_to_create_worker(pool))
Tejun Heoe22bee72010-06-29 10:07:14 +02001988 break;
1989 }
1990
Tejun Heo63d95a92012-07-12 14:46:37 -07001991 del_timer_sync(&pool->mayday_timer);
Tejun Heod565ed62013-01-24 11:01:33 -08001992 spin_lock_irq(&pool->lock);
Tejun Heo63d95a92012-07-12 14:46:37 -07001993 if (need_to_create_worker(pool))
Tejun Heoe22bee72010-06-29 10:07:14 +02001994 goto restart;
1995 return true;
1996}
1997
1998/**
Tejun Heoe22bee72010-06-29 10:07:14 +02001999 * manage_workers - manage worker pool
2000 * @worker: self
2001 *
Tejun Heo706026c2013-01-24 11:01:34 -08002002 * Assume the manager role and manage the worker pool @worker belongs
Tejun Heoe22bee72010-06-29 10:07:14 +02002003 * to. At any given time, there can be only zero or one manager per
Tejun Heo706026c2013-01-24 11:01:34 -08002004 * pool. The exclusion is handled automatically by this function.
Tejun Heoe22bee72010-06-29 10:07:14 +02002005 *
2006 * The caller can safely start processing works on false return. On
2007 * true return, it's guaranteed that need_to_create_worker() is false
2008 * and may_start_working() is true.
2009 *
2010 * CONTEXT:
Tejun Heod565ed62013-01-24 11:01:33 -08002011 * spin_lock_irq(pool->lock) which may be released and regrabbed
Tejun Heoe22bee72010-06-29 10:07:14 +02002012 * multiple times. Does GFP_KERNEL allocations.
2013 *
Yacine Belkadid185af32013-07-31 14:59:24 -07002014 * Return:
Libin2d498db2013-08-21 08:50:40 +08002015 * %false if the pool don't need management and the caller can safely start
2016 * processing works, %true indicates that the function released pool->lock
2017 * and reacquired it to perform some management function and that the
2018 * conditions that the caller verified while holding the lock before
2019 * calling the function might no longer be true.
Tejun Heoe22bee72010-06-29 10:07:14 +02002020 */
2021static bool manage_workers(struct worker *worker)
2022{
Tejun Heo63d95a92012-07-12 14:46:37 -07002023 struct worker_pool *pool = worker->pool;
Tejun Heoe22bee72010-06-29 10:07:14 +02002024 bool ret = false;
2025
Tejun Heobc3a1af2013-03-13 19:47:39 -07002026 /*
2027 * Managership is governed by two mutexes - manager_arb and
2028 * manager_mutex. manager_arb handles arbitration of manager role.
2029 * Anyone who successfully grabs manager_arb wins the arbitration
2030 * and becomes the manager. mutex_trylock() on pool->manager_arb
2031 * failure while holding pool->lock reliably indicates that someone
2032 * else is managing the pool and the worker which failed trylock
2033 * can proceed to executing work items. This means that anyone
2034 * grabbing manager_arb is responsible for actually performing
2035 * manager duties. If manager_arb is grabbed and released without
2036 * actual management, the pool may stall indefinitely.
2037 *
2038 * manager_mutex is used for exclusion of actual management
2039 * operations. The holder of manager_mutex can be sure that none
2040 * of management operations, including creation and destruction of
2041 * workers, won't take place until the mutex is released. Because
2042 * manager_mutex doesn't interfere with manager role arbitration,
2043 * it is guaranteed that the pool's management, while may be
2044 * delayed, won't be disturbed by someone else grabbing
2045 * manager_mutex.
2046 */
Tejun Heo34a06bd2013-03-12 11:30:00 -07002047 if (!mutex_trylock(&pool->manager_arb))
Tejun Heoe22bee72010-06-29 10:07:14 +02002048 return ret;
2049
Lai Jiangshanee378aa2012-09-10 10:03:44 -07002050 /*
Tejun Heobc3a1af2013-03-13 19:47:39 -07002051 * With manager arbitration won, manager_mutex would be free in
2052 * most cases. trylock first without dropping @pool->lock.
Lai Jiangshanee378aa2012-09-10 10:03:44 -07002053 */
Tejun Heobc3a1af2013-03-13 19:47:39 -07002054 if (unlikely(!mutex_trylock(&pool->manager_mutex))) {
Tejun Heod565ed62013-01-24 11:01:33 -08002055 spin_unlock_irq(&pool->lock);
Tejun Heobc3a1af2013-03-13 19:47:39 -07002056 mutex_lock(&pool->manager_mutex);
Joonsoo Kim8f174b12013-05-01 00:07:00 +09002057 spin_lock_irq(&pool->lock);
Lai Jiangshanee378aa2012-09-10 10:03:44 -07002058 ret = true;
2059 }
2060
Tejun Heo63d95a92012-07-12 14:46:37 -07002061 ret |= maybe_create_worker(pool);
Tejun Heoe22bee72010-06-29 10:07:14 +02002062
Tejun Heobc3a1af2013-03-13 19:47:39 -07002063 mutex_unlock(&pool->manager_mutex);
Tejun Heo34a06bd2013-03-12 11:30:00 -07002064 mutex_unlock(&pool->manager_arb);
Tejun Heoe22bee72010-06-29 10:07:14 +02002065 return ret;
2066}
2067
Tejun Heoa62428c2010-06-29 10:07:10 +02002068/**
2069 * process_one_work - process single work
Tejun Heoc34056a2010-06-29 10:07:11 +02002070 * @worker: self
Tejun Heoa62428c2010-06-29 10:07:10 +02002071 * @work: work to process
2072 *
2073 * Process @work. This function contains all the logics necessary to
2074 * process a single work including synchronization against and
2075 * interaction with other workers on the same cpu, queueing and
2076 * flushing. As long as context requirement is met, any worker can
2077 * call this function to process a work.
2078 *
2079 * CONTEXT:
Tejun Heod565ed62013-01-24 11:01:33 -08002080 * spin_lock_irq(pool->lock) which is released and regrabbed.
Tejun Heoa62428c2010-06-29 10:07:10 +02002081 */
Tejun Heoc34056a2010-06-29 10:07:11 +02002082static void process_one_work(struct worker *worker, struct work_struct *work)
Tejun Heod565ed62013-01-24 11:01:33 -08002083__releases(&pool->lock)
2084__acquires(&pool->lock)
Tejun Heoa62428c2010-06-29 10:07:10 +02002085{
Tejun Heo112202d2013-02-13 19:29:12 -08002086 struct pool_workqueue *pwq = get_work_pwq(work);
Tejun Heobd7bdd42012-07-12 14:46:37 -07002087 struct worker_pool *pool = worker->pool;
Tejun Heo112202d2013-02-13 19:29:12 -08002088 bool cpu_intensive = pwq->wq->flags & WQ_CPU_INTENSIVE;
Tejun Heo73f53c42010-06-29 10:07:11 +02002089 int work_color;
Tejun Heo7e116292010-06-29 10:07:13 +02002090 struct worker *collision;
Tejun Heoa62428c2010-06-29 10:07:10 +02002091#ifdef CONFIG_LOCKDEP
2092 /*
2093 * It is permissible to free the struct work_struct from
2094 * inside the function that is called from it, this we need to
2095 * take into account for lockdep too. To avoid bogus "held
2096 * lock freed" warnings as well as problems when looking into
2097 * work->lockdep_map, make a copy and use that here.
2098 */
Peter Zijlstra4d82a1d2012-05-15 08:06:19 -07002099 struct lockdep_map lockdep_map;
2100
2101 lockdep_copy_map(&lockdep_map, &work->lockdep_map);
Tejun Heoa62428c2010-06-29 10:07:10 +02002102#endif
Tejun Heo6fec10a2012-07-22 10:16:34 -07002103 /*
2104 * Ensure we're on the correct CPU. DISASSOCIATED test is
2105 * necessary to avoid spurious warnings from rescuers servicing the
Tejun Heo24647572013-01-24 11:01:33 -08002106 * unbound or a disassociated pool.
Tejun Heo6fec10a2012-07-22 10:16:34 -07002107 */
Lai Jiangshan5f7dabf2012-09-18 09:59:23 -07002108 WARN_ON_ONCE(!(worker->flags & WORKER_UNBOUND) &&
Tejun Heo24647572013-01-24 11:01:33 -08002109 !(pool->flags & POOL_DISASSOCIATED) &&
Tejun Heoec22ca52013-01-24 11:01:33 -08002110 raw_smp_processor_id() != pool->cpu);
Tejun Heo25511a42012-07-17 12:39:27 -07002111
Tejun Heo7e116292010-06-29 10:07:13 +02002112 /*
2113 * A single work shouldn't be executed concurrently by
2114 * multiple workers on a single cpu. Check whether anyone is
2115 * already processing the work. If so, defer the work to the
2116 * currently executing one.
2117 */
Tejun Heoc9e7cf22013-01-24 11:01:33 -08002118 collision = find_worker_executing_work(pool, work);
Tejun Heo7e116292010-06-29 10:07:13 +02002119 if (unlikely(collision)) {
2120 move_linked_works(work, &collision->scheduled, NULL);
2121 return;
2122 }
2123
Tejun Heo8930cab2012-08-03 10:30:45 -07002124 /* claim and dequeue */
Tejun Heoa62428c2010-06-29 10:07:10 +02002125 debug_work_deactivate(work);
Tejun Heoc9e7cf22013-01-24 11:01:33 -08002126 hash_add(pool->busy_hash, &worker->hentry, (unsigned long)work);
Tejun Heoc34056a2010-06-29 10:07:11 +02002127 worker->current_work = work;
Tejun Heoa2c1c572012-12-18 10:35:02 -08002128 worker->current_func = work->func;
Tejun Heo112202d2013-02-13 19:29:12 -08002129 worker->current_pwq = pwq;
Tejun Heo73f53c42010-06-29 10:07:11 +02002130 work_color = get_work_color(work);
Tejun Heo7a22ad72010-06-29 10:07:13 +02002131
Tejun Heoa62428c2010-06-29 10:07:10 +02002132 list_del_init(&work->entry);
2133
Tejun Heo649027d2010-06-29 10:07:14 +02002134 /*
Tejun Heofb0e7be2010-06-29 10:07:15 +02002135 * CPU intensive works don't participate in concurrency
2136 * management. They're the scheduler's responsibility.
2137 */
2138 if (unlikely(cpu_intensive))
2139 worker_set_flags(worker, WORKER_CPU_INTENSIVE, true);
2140
Tejun Heo974271c2012-07-12 14:46:37 -07002141 /*
Tejun Heod565ed62013-01-24 11:01:33 -08002142 * Unbound pool isn't concurrency managed and work items should be
Tejun Heo974271c2012-07-12 14:46:37 -07002143 * executed ASAP. Wake up another worker if necessary.
2144 */
Tejun Heo63d95a92012-07-12 14:46:37 -07002145 if ((worker->flags & WORKER_UNBOUND) && need_more_worker(pool))
2146 wake_up_worker(pool);
Tejun Heo974271c2012-07-12 14:46:37 -07002147
Tejun Heo8930cab2012-08-03 10:30:45 -07002148 /*
Tejun Heo7c3eed52013-01-24 11:01:33 -08002149 * Record the last pool and clear PENDING which should be the last
Tejun Heod565ed62013-01-24 11:01:33 -08002150 * update to @work. Also, do this inside @pool->lock so that
Tejun Heo23657bb2012-08-13 17:08:19 -07002151 * PENDING and queued state changes happen together while IRQ is
2152 * disabled.
Tejun Heo8930cab2012-08-03 10:30:45 -07002153 */
Tejun Heo7c3eed52013-01-24 11:01:33 -08002154 set_work_pool_and_clear_pending(work, pool->id);
Tejun Heoa62428c2010-06-29 10:07:10 +02002155
Tejun Heod565ed62013-01-24 11:01:33 -08002156 spin_unlock_irq(&pool->lock);
Tejun Heoa62428c2010-06-29 10:07:10 +02002157
Tejun Heo112202d2013-02-13 19:29:12 -08002158 lock_map_acquire_read(&pwq->wq->lockdep_map);
Tejun Heoa62428c2010-06-29 10:07:10 +02002159 lock_map_acquire(&lockdep_map);
Arjan van de Vene36c8862010-08-21 13:07:26 -07002160 trace_workqueue_execute_start(work);
Tejun Heoa2c1c572012-12-18 10:35:02 -08002161 worker->current_func(work);
Arjan van de Vene36c8862010-08-21 13:07:26 -07002162 /*
2163 * While we must be careful to not use "work" after this, the trace
2164 * point will only record its address.
2165 */
2166 trace_workqueue_execute_end(work);
Tejun Heoa62428c2010-06-29 10:07:10 +02002167 lock_map_release(&lockdep_map);
Tejun Heo112202d2013-02-13 19:29:12 -08002168 lock_map_release(&pwq->wq->lockdep_map);
Tejun Heoa62428c2010-06-29 10:07:10 +02002169
2170 if (unlikely(in_atomic() || lockdep_depth(current) > 0)) {
Valentin Ilie044c7822012-08-19 00:52:42 +03002171 pr_err("BUG: workqueue leaked lock or atomic: %s/0x%08x/%d\n"
2172 " last function: %pf\n",
Tejun Heoa2c1c572012-12-18 10:35:02 -08002173 current->comm, preempt_count(), task_pid_nr(current),
2174 worker->current_func);
Tejun Heoa62428c2010-06-29 10:07:10 +02002175 debug_show_held_locks(current);
2176 dump_stack();
2177 }
2178
Tejun Heob22ce272013-08-28 17:33:37 -04002179 /*
2180 * The following prevents a kworker from hogging CPU on !PREEMPT
2181 * kernels, where a requeueing work item waiting for something to
2182 * happen could deadlock with stop_machine as such work item could
2183 * indefinitely requeue itself while all other CPUs are trapped in
2184 * stop_machine.
2185 */
2186 cond_resched();
2187
Tejun Heod565ed62013-01-24 11:01:33 -08002188 spin_lock_irq(&pool->lock);
Tejun Heoa62428c2010-06-29 10:07:10 +02002189
Tejun Heofb0e7be2010-06-29 10:07:15 +02002190 /* clear cpu intensive status */
2191 if (unlikely(cpu_intensive))
2192 worker_clr_flags(worker, WORKER_CPU_INTENSIVE);
2193
Tejun Heoa62428c2010-06-29 10:07:10 +02002194 /* we're done with it, release */
Sasha Levin42f85702012-12-17 10:01:23 -05002195 hash_del(&worker->hentry);
Tejun Heoc34056a2010-06-29 10:07:11 +02002196 worker->current_work = NULL;
Tejun Heoa2c1c572012-12-18 10:35:02 -08002197 worker->current_func = NULL;
Tejun Heo112202d2013-02-13 19:29:12 -08002198 worker->current_pwq = NULL;
Tejun Heo3d1cb202013-04-30 15:27:22 -07002199 worker->desc_valid = false;
Tejun Heo112202d2013-02-13 19:29:12 -08002200 pwq_dec_nr_in_flight(pwq, work_color);
Tejun Heoa62428c2010-06-29 10:07:10 +02002201}
2202
Tejun Heoaffee4b2010-06-29 10:07:12 +02002203/**
2204 * process_scheduled_works - process scheduled works
2205 * @worker: self
2206 *
2207 * Process all scheduled works. Please note that the scheduled list
2208 * may change while processing a work, so this function repeatedly
2209 * fetches a work from the top and executes it.
2210 *
2211 * CONTEXT:
Tejun Heod565ed62013-01-24 11:01:33 -08002212 * spin_lock_irq(pool->lock) which may be released and regrabbed
Tejun Heoaffee4b2010-06-29 10:07:12 +02002213 * multiple times.
2214 */
2215static void process_scheduled_works(struct worker *worker)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002216{
Tejun Heoaffee4b2010-06-29 10:07:12 +02002217 while (!list_empty(&worker->scheduled)) {
2218 struct work_struct *work = list_first_entry(&worker->scheduled,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002219 struct work_struct, entry);
Tejun Heoc34056a2010-06-29 10:07:11 +02002220 process_one_work(worker, work);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002221 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002222}
2223
Tejun Heo4690c4a2010-06-29 10:07:10 +02002224/**
2225 * worker_thread - the worker thread function
Tejun Heoc34056a2010-06-29 10:07:11 +02002226 * @__worker: self
Tejun Heo4690c4a2010-06-29 10:07:10 +02002227 *
Tejun Heoc5aa87b2013-03-13 16:51:36 -07002228 * The worker thread function. All workers belong to a worker_pool -
2229 * either a per-cpu one or dynamic unbound one. These workers process all
2230 * work items regardless of their specific target workqueue. The only
2231 * exception is work items which belong to workqueues with a rescuer which
2232 * will be explained in rescuer_thread().
Yacine Belkadid185af32013-07-31 14:59:24 -07002233 *
2234 * Return: 0
Tejun Heo4690c4a2010-06-29 10:07:10 +02002235 */
Tejun Heoc34056a2010-06-29 10:07:11 +02002236static int worker_thread(void *__worker)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002237{
Tejun Heoc34056a2010-06-29 10:07:11 +02002238 struct worker *worker = __worker;
Tejun Heobd7bdd42012-07-12 14:46:37 -07002239 struct worker_pool *pool = worker->pool;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002240
Tejun Heoe22bee72010-06-29 10:07:14 +02002241 /* tell the scheduler that this is a workqueue worker */
2242 worker->task->flags |= PF_WQ_WORKER;
Tejun Heoc8e55f32010-06-29 10:07:12 +02002243woke_up:
Tejun Heod565ed62013-01-24 11:01:33 -08002244 spin_lock_irq(&pool->lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002245
Tejun Heoa9ab7752013-03-19 13:45:21 -07002246 /* am I supposed to die? */
2247 if (unlikely(worker->flags & WORKER_DIE)) {
Tejun Heod565ed62013-01-24 11:01:33 -08002248 spin_unlock_irq(&pool->lock);
Tejun Heoa9ab7752013-03-19 13:45:21 -07002249 WARN_ON_ONCE(!list_empty(&worker->entry));
2250 worker->task->flags &= ~PF_WQ_WORKER;
Lai Jiangshan60f5a4b2014-05-20 17:46:29 +08002251
2252 set_task_comm(worker->task, "kworker/dying");
2253 worker_detach_from_pool(worker, pool);
2254 kfree(worker);
Tejun Heoa9ab7752013-03-19 13:45:21 -07002255 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002256 }
2257
Tejun Heoc8e55f32010-06-29 10:07:12 +02002258 worker_leave_idle(worker);
Tejun Heodb7bccf2010-06-29 10:07:12 +02002259recheck:
Tejun Heoe22bee72010-06-29 10:07:14 +02002260 /* no more worker necessary? */
Tejun Heo63d95a92012-07-12 14:46:37 -07002261 if (!need_more_worker(pool))
Tejun Heoe22bee72010-06-29 10:07:14 +02002262 goto sleep;
2263
2264 /* do we need to manage? */
Tejun Heo63d95a92012-07-12 14:46:37 -07002265 if (unlikely(!may_start_working(pool)) && manage_workers(worker))
Tejun Heoe22bee72010-06-29 10:07:14 +02002266 goto recheck;
2267
Tejun Heoc8e55f32010-06-29 10:07:12 +02002268 /*
2269 * ->scheduled list can only be filled while a worker is
2270 * preparing to process a work or actually processing it.
2271 * Make sure nobody diddled with it while I was sleeping.
2272 */
Tejun Heo6183c002013-03-12 11:29:57 -07002273 WARN_ON_ONCE(!list_empty(&worker->scheduled));
Tejun Heoc8e55f32010-06-29 10:07:12 +02002274
Tejun Heoe22bee72010-06-29 10:07:14 +02002275 /*
Tejun Heoa9ab7752013-03-19 13:45:21 -07002276 * Finish PREP stage. We're guaranteed to have at least one idle
2277 * worker or that someone else has already assumed the manager
2278 * role. This is where @worker starts participating in concurrency
2279 * management if applicable and concurrency management is restored
2280 * after being rebound. See rebind_workers() for details.
Tejun Heoe22bee72010-06-29 10:07:14 +02002281 */
Tejun Heoa9ab7752013-03-19 13:45:21 -07002282 worker_clr_flags(worker, WORKER_PREP | WORKER_REBOUND);
Tejun Heoe22bee72010-06-29 10:07:14 +02002283
2284 do {
Tejun Heoc8e55f32010-06-29 10:07:12 +02002285 struct work_struct *work =
Tejun Heobd7bdd42012-07-12 14:46:37 -07002286 list_first_entry(&pool->worklist,
Tejun Heoc8e55f32010-06-29 10:07:12 +02002287 struct work_struct, entry);
2288
2289 if (likely(!(*work_data_bits(work) & WORK_STRUCT_LINKED))) {
2290 /* optimization path, not strictly necessary */
2291 process_one_work(worker, work);
2292 if (unlikely(!list_empty(&worker->scheduled)))
2293 process_scheduled_works(worker);
2294 } else {
2295 move_linked_works(work, &worker->scheduled, NULL);
2296 process_scheduled_works(worker);
2297 }
Tejun Heo63d95a92012-07-12 14:46:37 -07002298 } while (keep_working(pool));
Tejun Heoc8e55f32010-06-29 10:07:12 +02002299
Tejun Heoe22bee72010-06-29 10:07:14 +02002300 worker_set_flags(worker, WORKER_PREP, false);
Tejun Heod313dd82010-07-02 10:03:51 +02002301sleep:
Tejun Heoc8e55f32010-06-29 10:07:12 +02002302 /*
Tejun Heod565ed62013-01-24 11:01:33 -08002303 * pool->lock is held and there's no work to process and no need to
2304 * manage, sleep. Workers are woken up only while holding
2305 * pool->lock or from local cpu, so setting the current state
2306 * before releasing pool->lock is enough to prevent losing any
2307 * event.
Tejun Heoc8e55f32010-06-29 10:07:12 +02002308 */
2309 worker_enter_idle(worker);
2310 __set_current_state(TASK_INTERRUPTIBLE);
Tejun Heod565ed62013-01-24 11:01:33 -08002311 spin_unlock_irq(&pool->lock);
Tejun Heoc8e55f32010-06-29 10:07:12 +02002312 schedule();
2313 goto woke_up;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002314}
2315
Tejun Heoe22bee72010-06-29 10:07:14 +02002316/**
2317 * rescuer_thread - the rescuer thread function
Tejun Heo111c2252013-01-17 17:16:24 -08002318 * @__rescuer: self
Tejun Heoe22bee72010-06-29 10:07:14 +02002319 *
2320 * Workqueue rescuer thread function. There's one rescuer for each
Tejun Heo493008a2013-03-12 11:30:03 -07002321 * workqueue which has WQ_MEM_RECLAIM set.
Tejun Heoe22bee72010-06-29 10:07:14 +02002322 *
Tejun Heo706026c2013-01-24 11:01:34 -08002323 * Regular work processing on a pool may block trying to create a new
Tejun Heoe22bee72010-06-29 10:07:14 +02002324 * worker which uses GFP_KERNEL allocation which has slight chance of
2325 * developing into deadlock if some works currently on the same queue
2326 * need to be processed to satisfy the GFP_KERNEL allocation. This is
2327 * the problem rescuer solves.
2328 *
Tejun Heo706026c2013-01-24 11:01:34 -08002329 * When such condition is possible, the pool summons rescuers of all
2330 * workqueues which have works queued on the pool and let them process
Tejun Heoe22bee72010-06-29 10:07:14 +02002331 * those works so that forward progress can be guaranteed.
2332 *
2333 * This should happen rarely.
Yacine Belkadid185af32013-07-31 14:59:24 -07002334 *
2335 * Return: 0
Tejun Heoe22bee72010-06-29 10:07:14 +02002336 */
Tejun Heo111c2252013-01-17 17:16:24 -08002337static int rescuer_thread(void *__rescuer)
Tejun Heoe22bee72010-06-29 10:07:14 +02002338{
Tejun Heo111c2252013-01-17 17:16:24 -08002339 struct worker *rescuer = __rescuer;
2340 struct workqueue_struct *wq = rescuer->rescue_wq;
Tejun Heoe22bee72010-06-29 10:07:14 +02002341 struct list_head *scheduled = &rescuer->scheduled;
Lai Jiangshan4d595b82014-04-18 11:04:16 -04002342 bool should_stop;
Tejun Heoe22bee72010-06-29 10:07:14 +02002343
2344 set_user_nice(current, RESCUER_NICE_LEVEL);
Tejun Heo111c2252013-01-17 17:16:24 -08002345
2346 /*
2347 * Mark rescuer as worker too. As WORKER_PREP is never cleared, it
2348 * doesn't participate in concurrency management.
2349 */
2350 rescuer->task->flags |= PF_WQ_WORKER;
Tejun Heoe22bee72010-06-29 10:07:14 +02002351repeat:
2352 set_current_state(TASK_INTERRUPTIBLE);
2353
Lai Jiangshan4d595b82014-04-18 11:04:16 -04002354 /*
2355 * By the time the rescuer is requested to stop, the workqueue
2356 * shouldn't have any work pending, but @wq->maydays may still have
2357 * pwq(s) queued. This can happen by non-rescuer workers consuming
2358 * all the work items before the rescuer got to them. Go through
2359 * @wq->maydays processing before acting on should_stop so that the
2360 * list is always empty on exit.
2361 */
2362 should_stop = kthread_should_stop();
Tejun Heoe22bee72010-06-29 10:07:14 +02002363
Tejun Heo493a1722013-03-12 11:29:59 -07002364 /* see whether any pwq is asking for help */
Tejun Heo2e109a22013-03-13 19:47:40 -07002365 spin_lock_irq(&wq_mayday_lock);
Tejun Heo493a1722013-03-12 11:29:59 -07002366
2367 while (!list_empty(&wq->maydays)) {
2368 struct pool_workqueue *pwq = list_first_entry(&wq->maydays,
2369 struct pool_workqueue, mayday_node);
Tejun Heo112202d2013-02-13 19:29:12 -08002370 struct worker_pool *pool = pwq->pool;
Tejun Heoe22bee72010-06-29 10:07:14 +02002371 struct work_struct *work, *n;
2372
2373 __set_current_state(TASK_RUNNING);
Tejun Heo493a1722013-03-12 11:29:59 -07002374 list_del_init(&pwq->mayday_node);
2375
Tejun Heo2e109a22013-03-13 19:47:40 -07002376 spin_unlock_irq(&wq_mayday_lock);
Tejun Heoe22bee72010-06-29 10:07:14 +02002377
2378 /* migrate to the target cpu if possible */
Lai Jiangshanf36dc672013-02-19 12:17:02 -08002379 worker_maybe_bind_and_lock(pool);
Lai Jiangshanb3104102013-02-19 12:17:02 -08002380 rescuer->pool = pool;
Tejun Heoe22bee72010-06-29 10:07:14 +02002381
2382 /*
2383 * Slurp in all works issued via this workqueue and
2384 * process'em.
2385 */
Tejun Heo6183c002013-03-12 11:29:57 -07002386 WARN_ON_ONCE(!list_empty(&rescuer->scheduled));
Tejun Heobd7bdd42012-07-12 14:46:37 -07002387 list_for_each_entry_safe(work, n, &pool->worklist, entry)
Tejun Heo112202d2013-02-13 19:29:12 -08002388 if (get_work_pwq(work) == pwq)
Tejun Heoe22bee72010-06-29 10:07:14 +02002389 move_linked_works(work, scheduled, &n);
2390
2391 process_scheduled_works(rescuer);
Tejun Heo75769582011-02-14 14:04:46 +01002392
2393 /*
Lai Jiangshan77668c82014-04-18 11:04:16 -04002394 * Put the reference grabbed by send_mayday(). @pool won't
2395 * go away while we're holding its lock.
2396 */
2397 put_pwq(pwq);
2398
2399 /*
Tejun Heod565ed62013-01-24 11:01:33 -08002400 * Leave this pool. If keep_working() is %true, notify a
Tejun Heo75769582011-02-14 14:04:46 +01002401 * regular worker; otherwise, we end up with 0 concurrency
2402 * and stalling the execution.
2403 */
Tejun Heo63d95a92012-07-12 14:46:37 -07002404 if (keep_working(pool))
2405 wake_up_worker(pool);
Tejun Heo75769582011-02-14 14:04:46 +01002406
Lai Jiangshanb3104102013-02-19 12:17:02 -08002407 rescuer->pool = NULL;
Tejun Heo493a1722013-03-12 11:29:59 -07002408 spin_unlock(&pool->lock);
Tejun Heo2e109a22013-03-13 19:47:40 -07002409 spin_lock(&wq_mayday_lock);
Tejun Heoe22bee72010-06-29 10:07:14 +02002410 }
2411
Tejun Heo2e109a22013-03-13 19:47:40 -07002412 spin_unlock_irq(&wq_mayday_lock);
Tejun Heo493a1722013-03-12 11:29:59 -07002413
Lai Jiangshan4d595b82014-04-18 11:04:16 -04002414 if (should_stop) {
2415 __set_current_state(TASK_RUNNING);
2416 rescuer->task->flags &= ~PF_WQ_WORKER;
2417 return 0;
2418 }
2419
Tejun Heo111c2252013-01-17 17:16:24 -08002420 /* rescuers should never participate in concurrency management */
2421 WARN_ON_ONCE(!(rescuer->flags & WORKER_NOT_RUNNING));
Tejun Heoe22bee72010-06-29 10:07:14 +02002422 schedule();
2423 goto repeat;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002424}
2425
Oleg Nesterovfc2e4d72007-05-09 02:33:51 -07002426struct wq_barrier {
2427 struct work_struct work;
2428 struct completion done;
2429};
2430
2431static void wq_barrier_func(struct work_struct *work)
2432{
2433 struct wq_barrier *barr = container_of(work, struct wq_barrier, work);
2434 complete(&barr->done);
2435}
2436
Tejun Heo4690c4a2010-06-29 10:07:10 +02002437/**
2438 * insert_wq_barrier - insert a barrier work
Tejun Heo112202d2013-02-13 19:29:12 -08002439 * @pwq: pwq to insert barrier into
Tejun Heo4690c4a2010-06-29 10:07:10 +02002440 * @barr: wq_barrier to insert
Tejun Heoaffee4b2010-06-29 10:07:12 +02002441 * @target: target work to attach @barr to
2442 * @worker: worker currently executing @target, NULL if @target is not executing
Tejun Heo4690c4a2010-06-29 10:07:10 +02002443 *
Tejun Heoaffee4b2010-06-29 10:07:12 +02002444 * @barr is linked to @target such that @barr is completed only after
2445 * @target finishes execution. Please note that the ordering
2446 * guarantee is observed only with respect to @target and on the local
2447 * cpu.
2448 *
2449 * Currently, a queued barrier can't be canceled. This is because
2450 * try_to_grab_pending() can't determine whether the work to be
2451 * grabbed is at the head of the queue and thus can't clear LINKED
2452 * flag of the previous work while there must be a valid next work
2453 * after a work with LINKED flag set.
2454 *
2455 * Note that when @worker is non-NULL, @target may be modified
Tejun Heo112202d2013-02-13 19:29:12 -08002456 * underneath us, so we can't reliably determine pwq from @target.
Tejun Heo4690c4a2010-06-29 10:07:10 +02002457 *
2458 * CONTEXT:
Tejun Heod565ed62013-01-24 11:01:33 -08002459 * spin_lock_irq(pool->lock).
Tejun Heo4690c4a2010-06-29 10:07:10 +02002460 */
Tejun Heo112202d2013-02-13 19:29:12 -08002461static void insert_wq_barrier(struct pool_workqueue *pwq,
Tejun Heoaffee4b2010-06-29 10:07:12 +02002462 struct wq_barrier *barr,
2463 struct work_struct *target, struct worker *worker)
Oleg Nesterovfc2e4d72007-05-09 02:33:51 -07002464{
Tejun Heoaffee4b2010-06-29 10:07:12 +02002465 struct list_head *head;
2466 unsigned int linked = 0;
2467
Thomas Gleixnerdc186ad2009-11-16 01:09:48 +09002468 /*
Tejun Heod565ed62013-01-24 11:01:33 -08002469 * debugobject calls are safe here even with pool->lock locked
Thomas Gleixnerdc186ad2009-11-16 01:09:48 +09002470 * as we know for sure that this will not trigger any of the
2471 * checks and call back into the fixup functions where we
2472 * might deadlock.
2473 */
Andrew Mortonca1cab32010-10-26 14:22:34 -07002474 INIT_WORK_ONSTACK(&barr->work, wq_barrier_func);
Tejun Heo22df02b2010-06-29 10:07:10 +02002475 __set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(&barr->work));
Oleg Nesterovfc2e4d72007-05-09 02:33:51 -07002476 init_completion(&barr->done);
Oleg Nesterov83c22522007-05-09 02:33:54 -07002477
Tejun Heoaffee4b2010-06-29 10:07:12 +02002478 /*
2479 * If @target is currently being executed, schedule the
2480 * barrier to the worker; otherwise, put it after @target.
2481 */
2482 if (worker)
2483 head = worker->scheduled.next;
2484 else {
2485 unsigned long *bits = work_data_bits(target);
2486
2487 head = target->entry.next;
2488 /* there can already be other linked works, inherit and set */
2489 linked = *bits & WORK_STRUCT_LINKED;
2490 __set_bit(WORK_STRUCT_LINKED_BIT, bits);
2491 }
2492
Thomas Gleixnerdc186ad2009-11-16 01:09:48 +09002493 debug_work_activate(&barr->work);
Tejun Heo112202d2013-02-13 19:29:12 -08002494 insert_work(pwq, &barr->work, head,
Tejun Heoaffee4b2010-06-29 10:07:12 +02002495 work_color_to_flags(WORK_NO_COLOR) | linked);
Oleg Nesterovfc2e4d72007-05-09 02:33:51 -07002496}
2497
Tejun Heo73f53c42010-06-29 10:07:11 +02002498/**
Tejun Heo112202d2013-02-13 19:29:12 -08002499 * flush_workqueue_prep_pwqs - prepare pwqs for workqueue flushing
Tejun Heo73f53c42010-06-29 10:07:11 +02002500 * @wq: workqueue being flushed
2501 * @flush_color: new flush color, < 0 for no-op
2502 * @work_color: new work color, < 0 for no-op
2503 *
Tejun Heo112202d2013-02-13 19:29:12 -08002504 * Prepare pwqs for workqueue flushing.
Tejun Heo73f53c42010-06-29 10:07:11 +02002505 *
Tejun Heo112202d2013-02-13 19:29:12 -08002506 * If @flush_color is non-negative, flush_color on all pwqs should be
2507 * -1. If no pwq has in-flight commands at the specified color, all
2508 * pwq->flush_color's stay at -1 and %false is returned. If any pwq
2509 * has in flight commands, its pwq->flush_color is set to
2510 * @flush_color, @wq->nr_pwqs_to_flush is updated accordingly, pwq
Tejun Heo73f53c42010-06-29 10:07:11 +02002511 * wakeup logic is armed and %true is returned.
2512 *
2513 * The caller should have initialized @wq->first_flusher prior to
2514 * calling this function with non-negative @flush_color. If
2515 * @flush_color is negative, no flush color update is done and %false
2516 * is returned.
2517 *
Tejun Heo112202d2013-02-13 19:29:12 -08002518 * If @work_color is non-negative, all pwqs should have the same
Tejun Heo73f53c42010-06-29 10:07:11 +02002519 * work_color which is previous to @work_color and all will be
2520 * advanced to @work_color.
2521 *
2522 * CONTEXT:
Lai Jiangshan3c25a552013-03-25 16:57:17 -07002523 * mutex_lock(wq->mutex).
Tejun Heo73f53c42010-06-29 10:07:11 +02002524 *
Yacine Belkadid185af32013-07-31 14:59:24 -07002525 * Return:
Tejun Heo73f53c42010-06-29 10:07:11 +02002526 * %true if @flush_color >= 0 and there's something to flush. %false
2527 * otherwise.
2528 */
Tejun Heo112202d2013-02-13 19:29:12 -08002529static bool flush_workqueue_prep_pwqs(struct workqueue_struct *wq,
Tejun Heo73f53c42010-06-29 10:07:11 +02002530 int flush_color, int work_color)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002531{
Tejun Heo73f53c42010-06-29 10:07:11 +02002532 bool wait = false;
Tejun Heo49e3cf42013-03-12 11:29:58 -07002533 struct pool_workqueue *pwq;
Oleg Nesterov14441962007-05-23 13:57:57 -07002534
Tejun Heo73f53c42010-06-29 10:07:11 +02002535 if (flush_color >= 0) {
Tejun Heo6183c002013-03-12 11:29:57 -07002536 WARN_ON_ONCE(atomic_read(&wq->nr_pwqs_to_flush));
Tejun Heo112202d2013-02-13 19:29:12 -08002537 atomic_set(&wq->nr_pwqs_to_flush, 1);
Thomas Gleixnerdc186ad2009-11-16 01:09:48 +09002538 }
Oleg Nesterov14441962007-05-23 13:57:57 -07002539
Tejun Heo49e3cf42013-03-12 11:29:58 -07002540 for_each_pwq(pwq, wq) {
Tejun Heo112202d2013-02-13 19:29:12 -08002541 struct worker_pool *pool = pwq->pool;
Tejun Heo73f53c42010-06-29 10:07:11 +02002542
Lai Jiangshanb09f4fd2013-03-25 16:57:18 -07002543 spin_lock_irq(&pool->lock);
Tejun Heo73f53c42010-06-29 10:07:11 +02002544
2545 if (flush_color >= 0) {
Tejun Heo6183c002013-03-12 11:29:57 -07002546 WARN_ON_ONCE(pwq->flush_color != -1);
Tejun Heo73f53c42010-06-29 10:07:11 +02002547
Tejun Heo112202d2013-02-13 19:29:12 -08002548 if (pwq->nr_in_flight[flush_color]) {
2549 pwq->flush_color = flush_color;
2550 atomic_inc(&wq->nr_pwqs_to_flush);
Tejun Heo73f53c42010-06-29 10:07:11 +02002551 wait = true;
2552 }
2553 }
2554
2555 if (work_color >= 0) {
Tejun Heo6183c002013-03-12 11:29:57 -07002556 WARN_ON_ONCE(work_color != work_next_color(pwq->work_color));
Tejun Heo112202d2013-02-13 19:29:12 -08002557 pwq->work_color = work_color;
Tejun Heo73f53c42010-06-29 10:07:11 +02002558 }
2559
Lai Jiangshanb09f4fd2013-03-25 16:57:18 -07002560 spin_unlock_irq(&pool->lock);
Tejun Heo73f53c42010-06-29 10:07:11 +02002561 }
2562
Tejun Heo112202d2013-02-13 19:29:12 -08002563 if (flush_color >= 0 && atomic_dec_and_test(&wq->nr_pwqs_to_flush))
Tejun Heo73f53c42010-06-29 10:07:11 +02002564 complete(&wq->first_flusher->done);
2565
2566 return wait;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002567}
2568
Rolf Eike Beer0fcb78c2006-07-30 03:03:42 -07002569/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07002570 * flush_workqueue - ensure that any scheduled work has run to completion.
Rolf Eike Beer0fcb78c2006-07-30 03:03:42 -07002571 * @wq: workqueue to flush
Linus Torvalds1da177e2005-04-16 15:20:36 -07002572 *
Tejun Heoc5aa87b2013-03-13 16:51:36 -07002573 * This function sleeps until all work items which were queued on entry
2574 * have finished execution, but it is not livelocked by new incoming ones.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002575 */
Harvey Harrison7ad5b3a2008-02-08 04:19:53 -08002576void flush_workqueue(struct workqueue_struct *wq)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002577{
Tejun Heo73f53c42010-06-29 10:07:11 +02002578 struct wq_flusher this_flusher = {
2579 .list = LIST_HEAD_INIT(this_flusher.list),
2580 .flush_color = -1,
2581 .done = COMPLETION_INITIALIZER_ONSTACK(this_flusher.done),
2582 };
2583 int next_color;
Oleg Nesterovb1f4ec12007-05-09 02:34:12 -07002584
Ingo Molnar3295f0e2008-08-11 10:30:30 +02002585 lock_map_acquire(&wq->lockdep_map);
2586 lock_map_release(&wq->lockdep_map);
Tejun Heo73f53c42010-06-29 10:07:11 +02002587
Lai Jiangshan3c25a552013-03-25 16:57:17 -07002588 mutex_lock(&wq->mutex);
Tejun Heo73f53c42010-06-29 10:07:11 +02002589
2590 /*
2591 * Start-to-wait phase
2592 */
2593 next_color = work_next_color(wq->work_color);
2594
2595 if (next_color != wq->flush_color) {
2596 /*
2597 * Color space is not full. The current work_color
2598 * becomes our flush_color and work_color is advanced
2599 * by one.
2600 */
Tejun Heo6183c002013-03-12 11:29:57 -07002601 WARN_ON_ONCE(!list_empty(&wq->flusher_overflow));
Tejun Heo73f53c42010-06-29 10:07:11 +02002602 this_flusher.flush_color = wq->work_color;
2603 wq->work_color = next_color;
2604
2605 if (!wq->first_flusher) {
2606 /* no flush in progress, become the first flusher */
Tejun Heo6183c002013-03-12 11:29:57 -07002607 WARN_ON_ONCE(wq->flush_color != this_flusher.flush_color);
Tejun Heo73f53c42010-06-29 10:07:11 +02002608
2609 wq->first_flusher = &this_flusher;
2610
Tejun Heo112202d2013-02-13 19:29:12 -08002611 if (!flush_workqueue_prep_pwqs(wq, wq->flush_color,
Tejun Heo73f53c42010-06-29 10:07:11 +02002612 wq->work_color)) {
2613 /* nothing to flush, done */
2614 wq->flush_color = next_color;
2615 wq->first_flusher = NULL;
2616 goto out_unlock;
2617 }
2618 } else {
2619 /* wait in queue */
Tejun Heo6183c002013-03-12 11:29:57 -07002620 WARN_ON_ONCE(wq->flush_color == this_flusher.flush_color);
Tejun Heo73f53c42010-06-29 10:07:11 +02002621 list_add_tail(&this_flusher.list, &wq->flusher_queue);
Tejun Heo112202d2013-02-13 19:29:12 -08002622 flush_workqueue_prep_pwqs(wq, -1, wq->work_color);
Tejun Heo73f53c42010-06-29 10:07:11 +02002623 }
2624 } else {
2625 /*
2626 * Oops, color space is full, wait on overflow queue.
2627 * The next flush completion will assign us
2628 * flush_color and transfer to flusher_queue.
2629 */
2630 list_add_tail(&this_flusher.list, &wq->flusher_overflow);
2631 }
2632
Lai Jiangshan3c25a552013-03-25 16:57:17 -07002633 mutex_unlock(&wq->mutex);
Tejun Heo73f53c42010-06-29 10:07:11 +02002634
2635 wait_for_completion(&this_flusher.done);
2636
2637 /*
2638 * Wake-up-and-cascade phase
2639 *
2640 * First flushers are responsible for cascading flushes and
2641 * handling overflow. Non-first flushers can simply return.
2642 */
2643 if (wq->first_flusher != &this_flusher)
2644 return;
2645
Lai Jiangshan3c25a552013-03-25 16:57:17 -07002646 mutex_lock(&wq->mutex);
Tejun Heo73f53c42010-06-29 10:07:11 +02002647
Tejun Heo4ce48b32010-07-02 10:03:51 +02002648 /* we might have raced, check again with mutex held */
2649 if (wq->first_flusher != &this_flusher)
2650 goto out_unlock;
2651
Tejun Heo73f53c42010-06-29 10:07:11 +02002652 wq->first_flusher = NULL;
2653
Tejun Heo6183c002013-03-12 11:29:57 -07002654 WARN_ON_ONCE(!list_empty(&this_flusher.list));
2655 WARN_ON_ONCE(wq->flush_color != this_flusher.flush_color);
Tejun Heo73f53c42010-06-29 10:07:11 +02002656
2657 while (true) {
2658 struct wq_flusher *next, *tmp;
2659
2660 /* complete all the flushers sharing the current flush color */
2661 list_for_each_entry_safe(next, tmp, &wq->flusher_queue, list) {
2662 if (next->flush_color != wq->flush_color)
2663 break;
2664 list_del_init(&next->list);
2665 complete(&next->done);
2666 }
2667
Tejun Heo6183c002013-03-12 11:29:57 -07002668 WARN_ON_ONCE(!list_empty(&wq->flusher_overflow) &&
2669 wq->flush_color != work_next_color(wq->work_color));
Tejun Heo73f53c42010-06-29 10:07:11 +02002670
2671 /* this flush_color is finished, advance by one */
2672 wq->flush_color = work_next_color(wq->flush_color);
2673
2674 /* one color has been freed, handle overflow queue */
2675 if (!list_empty(&wq->flusher_overflow)) {
2676 /*
2677 * Assign the same color to all overflowed
2678 * flushers, advance work_color and append to
2679 * flusher_queue. This is the start-to-wait
2680 * phase for these overflowed flushers.
2681 */
2682 list_for_each_entry(tmp, &wq->flusher_overflow, list)
2683 tmp->flush_color = wq->work_color;
2684
2685 wq->work_color = work_next_color(wq->work_color);
2686
2687 list_splice_tail_init(&wq->flusher_overflow,
2688 &wq->flusher_queue);
Tejun Heo112202d2013-02-13 19:29:12 -08002689 flush_workqueue_prep_pwqs(wq, -1, wq->work_color);
Tejun Heo73f53c42010-06-29 10:07:11 +02002690 }
2691
2692 if (list_empty(&wq->flusher_queue)) {
Tejun Heo6183c002013-03-12 11:29:57 -07002693 WARN_ON_ONCE(wq->flush_color != wq->work_color);
Tejun Heo73f53c42010-06-29 10:07:11 +02002694 break;
2695 }
2696
2697 /*
2698 * Need to flush more colors. Make the next flusher
Tejun Heo112202d2013-02-13 19:29:12 -08002699 * the new first flusher and arm pwqs.
Tejun Heo73f53c42010-06-29 10:07:11 +02002700 */
Tejun Heo6183c002013-03-12 11:29:57 -07002701 WARN_ON_ONCE(wq->flush_color == wq->work_color);
2702 WARN_ON_ONCE(wq->flush_color != next->flush_color);
Tejun Heo73f53c42010-06-29 10:07:11 +02002703
2704 list_del_init(&next->list);
2705 wq->first_flusher = next;
2706
Tejun Heo112202d2013-02-13 19:29:12 -08002707 if (flush_workqueue_prep_pwqs(wq, wq->flush_color, -1))
Tejun Heo73f53c42010-06-29 10:07:11 +02002708 break;
2709
2710 /*
2711 * Meh... this color is already done, clear first
2712 * flusher and repeat cascading.
2713 */
2714 wq->first_flusher = NULL;
2715 }
2716
2717out_unlock:
Lai Jiangshan3c25a552013-03-25 16:57:17 -07002718 mutex_unlock(&wq->mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002719}
Dave Jonesae90dd52006-06-30 01:40:45 -04002720EXPORT_SYMBOL_GPL(flush_workqueue);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002721
Tejun Heo9c5a2ba2011-04-05 18:01:44 +02002722/**
2723 * drain_workqueue - drain a workqueue
2724 * @wq: workqueue to drain
2725 *
2726 * Wait until the workqueue becomes empty. While draining is in progress,
2727 * only chain queueing is allowed. IOW, only currently pending or running
2728 * work items on @wq can queue further work items on it. @wq is flushed
2729 * repeatedly until it becomes empty. The number of flushing is detemined
2730 * by the depth of chaining and should be relatively short. Whine if it
2731 * takes too long.
2732 */
2733void drain_workqueue(struct workqueue_struct *wq)
2734{
2735 unsigned int flush_cnt = 0;
Tejun Heo49e3cf42013-03-12 11:29:58 -07002736 struct pool_workqueue *pwq;
Tejun Heo9c5a2ba2011-04-05 18:01:44 +02002737
2738 /*
2739 * __queue_work() needs to test whether there are drainers, is much
2740 * hotter than drain_workqueue() and already looks at @wq->flags.
Tejun Heo618b01e2013-03-12 11:30:04 -07002741 * Use __WQ_DRAINING so that queue doesn't have to check nr_drainers.
Tejun Heo9c5a2ba2011-04-05 18:01:44 +02002742 */
Lai Jiangshan87fc7412013-03-25 16:57:18 -07002743 mutex_lock(&wq->mutex);
Tejun Heo9c5a2ba2011-04-05 18:01:44 +02002744 if (!wq->nr_drainers++)
Tejun Heo618b01e2013-03-12 11:30:04 -07002745 wq->flags |= __WQ_DRAINING;
Lai Jiangshan87fc7412013-03-25 16:57:18 -07002746 mutex_unlock(&wq->mutex);
Tejun Heo9c5a2ba2011-04-05 18:01:44 +02002747reflush:
2748 flush_workqueue(wq);
2749
Lai Jiangshanb09f4fd2013-03-25 16:57:18 -07002750 mutex_lock(&wq->mutex);
Tejun Heo76af4d92013-03-12 11:30:00 -07002751
Tejun Heo49e3cf42013-03-12 11:29:58 -07002752 for_each_pwq(pwq, wq) {
Thomas Tuttlefa2563e2011-09-14 16:22:28 -07002753 bool drained;
Tejun Heo9c5a2ba2011-04-05 18:01:44 +02002754
Lai Jiangshanb09f4fd2013-03-25 16:57:18 -07002755 spin_lock_irq(&pwq->pool->lock);
Tejun Heo112202d2013-02-13 19:29:12 -08002756 drained = !pwq->nr_active && list_empty(&pwq->delayed_works);
Lai Jiangshanb09f4fd2013-03-25 16:57:18 -07002757 spin_unlock_irq(&pwq->pool->lock);
Thomas Tuttlefa2563e2011-09-14 16:22:28 -07002758
2759 if (drained)
Tejun Heo9c5a2ba2011-04-05 18:01:44 +02002760 continue;
2761
2762 if (++flush_cnt == 10 ||
2763 (flush_cnt % 100 == 0 && flush_cnt <= 1000))
Tejun Heoc5aa87b2013-03-13 16:51:36 -07002764 pr_warn("workqueue %s: drain_workqueue() isn't complete after %u tries\n",
Valentin Ilie044c7822012-08-19 00:52:42 +03002765 wq->name, flush_cnt);
Tejun Heo76af4d92013-03-12 11:30:00 -07002766
Lai Jiangshanb09f4fd2013-03-25 16:57:18 -07002767 mutex_unlock(&wq->mutex);
Tejun Heo9c5a2ba2011-04-05 18:01:44 +02002768 goto reflush;
2769 }
2770
Tejun Heo9c5a2ba2011-04-05 18:01:44 +02002771 if (!--wq->nr_drainers)
Tejun Heo618b01e2013-03-12 11:30:04 -07002772 wq->flags &= ~__WQ_DRAINING;
Lai Jiangshan87fc7412013-03-25 16:57:18 -07002773 mutex_unlock(&wq->mutex);
Tejun Heo9c5a2ba2011-04-05 18:01:44 +02002774}
2775EXPORT_SYMBOL_GPL(drain_workqueue);
2776
Tejun Heo606a5022012-08-20 14:51:23 -07002777static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr)
Tejun Heobaf59022010-09-16 10:42:16 +02002778{
2779 struct worker *worker = NULL;
Tejun Heoc9e7cf22013-01-24 11:01:33 -08002780 struct worker_pool *pool;
Tejun Heo112202d2013-02-13 19:29:12 -08002781 struct pool_workqueue *pwq;
Tejun Heobaf59022010-09-16 10:42:16 +02002782
2783 might_sleep();
Tejun Heobaf59022010-09-16 10:42:16 +02002784
Tejun Heofa1b54e2013-03-12 11:30:00 -07002785 local_irq_disable();
2786 pool = get_work_pool(work);
2787 if (!pool) {
2788 local_irq_enable();
2789 return false;
2790 }
2791
2792 spin_lock(&pool->lock);
Lai Jiangshan0b3dae62013-02-06 18:04:53 -08002793 /* see the comment in try_to_grab_pending() with the same code */
Tejun Heo112202d2013-02-13 19:29:12 -08002794 pwq = get_work_pwq(work);
2795 if (pwq) {
2796 if (unlikely(pwq->pool != pool))
Tejun Heobaf59022010-09-16 10:42:16 +02002797 goto already_gone;
Tejun Heo606a5022012-08-20 14:51:23 -07002798 } else {
Tejun Heoc9e7cf22013-01-24 11:01:33 -08002799 worker = find_worker_executing_work(pool, work);
Tejun Heobaf59022010-09-16 10:42:16 +02002800 if (!worker)
2801 goto already_gone;
Tejun Heo112202d2013-02-13 19:29:12 -08002802 pwq = worker->current_pwq;
Tejun Heo606a5022012-08-20 14:51:23 -07002803 }
Tejun Heobaf59022010-09-16 10:42:16 +02002804
Tejun Heo112202d2013-02-13 19:29:12 -08002805 insert_wq_barrier(pwq, barr, work, worker);
Tejun Heod565ed62013-01-24 11:01:33 -08002806 spin_unlock_irq(&pool->lock);
Tejun Heobaf59022010-09-16 10:42:16 +02002807
Tejun Heoe1594892011-01-09 23:32:15 +01002808 /*
2809 * If @max_active is 1 or rescuer is in use, flushing another work
2810 * item on the same workqueue may lead to deadlock. Make sure the
2811 * flusher is not running on the same workqueue by verifying write
2812 * access.
2813 */
Tejun Heo493008a2013-03-12 11:30:03 -07002814 if (pwq->wq->saved_max_active == 1 || pwq->wq->rescuer)
Tejun Heo112202d2013-02-13 19:29:12 -08002815 lock_map_acquire(&pwq->wq->lockdep_map);
Tejun Heoe1594892011-01-09 23:32:15 +01002816 else
Tejun Heo112202d2013-02-13 19:29:12 -08002817 lock_map_acquire_read(&pwq->wq->lockdep_map);
2818 lock_map_release(&pwq->wq->lockdep_map);
Tejun Heoe1594892011-01-09 23:32:15 +01002819
Tejun Heobaf59022010-09-16 10:42:16 +02002820 return true;
2821already_gone:
Tejun Heod565ed62013-01-24 11:01:33 -08002822 spin_unlock_irq(&pool->lock);
Tejun Heobaf59022010-09-16 10:42:16 +02002823 return false;
2824}
2825
Oleg Nesterovdb700892008-07-25 01:47:49 -07002826/**
Tejun Heo401a8d02010-09-16 10:36:00 +02002827 * flush_work - wait for a work to finish executing the last queueing instance
2828 * @work: the work to flush
Oleg Nesterovdb700892008-07-25 01:47:49 -07002829 *
Tejun Heo606a5022012-08-20 14:51:23 -07002830 * Wait until @work has finished execution. @work is guaranteed to be idle
2831 * on return if it hasn't been requeued since flush started.
Tejun Heo401a8d02010-09-16 10:36:00 +02002832 *
Yacine Belkadid185af32013-07-31 14:59:24 -07002833 * Return:
Tejun Heo401a8d02010-09-16 10:36:00 +02002834 * %true if flush_work() waited for the work to finish execution,
2835 * %false if it was already idle.
Oleg Nesterovdb700892008-07-25 01:47:49 -07002836 */
Tejun Heo401a8d02010-09-16 10:36:00 +02002837bool flush_work(struct work_struct *work)
Oleg Nesterovdb700892008-07-25 01:47:49 -07002838{
Bjorn Helgaas12997d12013-11-18 11:00:29 -07002839 struct wq_barrier barr;
2840
Stephen Boyd0976dfc2012-04-20 17:28:50 -07002841 lock_map_acquire(&work->lockdep_map);
2842 lock_map_release(&work->lockdep_map);
2843
Bjorn Helgaas12997d12013-11-18 11:00:29 -07002844 if (start_flush_work(work, &barr)) {
2845 wait_for_completion(&barr.done);
2846 destroy_work_on_stack(&barr.work);
2847 return true;
2848 } else {
2849 return false;
2850 }
Oleg Nesterovdb700892008-07-25 01:47:49 -07002851}
2852EXPORT_SYMBOL_GPL(flush_work);
2853
Tejun Heo36e227d2012-08-03 10:30:46 -07002854static bool __cancel_work_timer(struct work_struct *work, bool is_dwork)
Tejun Heo401a8d02010-09-16 10:36:00 +02002855{
Tejun Heobbb68df2012-08-03 10:30:46 -07002856 unsigned long flags;
Oleg Nesterov1f1f6422007-07-15 23:41:44 -07002857 int ret;
2858
2859 do {
Tejun Heobbb68df2012-08-03 10:30:46 -07002860 ret = try_to_grab_pending(work, is_dwork, &flags);
2861 /*
2862 * If someone else is canceling, wait for the same event it
2863 * would be waiting for before retrying.
2864 */
2865 if (unlikely(ret == -ENOENT))
Tejun Heo606a5022012-08-20 14:51:23 -07002866 flush_work(work);
Oleg Nesterov1f1f6422007-07-15 23:41:44 -07002867 } while (unlikely(ret < 0));
2868
Tejun Heobbb68df2012-08-03 10:30:46 -07002869 /* tell other tasks trying to grab @work to back off */
2870 mark_work_canceling(work);
2871 local_irq_restore(flags);
2872
Tejun Heo606a5022012-08-20 14:51:23 -07002873 flush_work(work);
Tejun Heo7a22ad72010-06-29 10:07:13 +02002874 clear_work_data(work);
Oleg Nesterov1f1f6422007-07-15 23:41:44 -07002875 return ret;
2876}
2877
Oleg Nesterov6e84d642007-05-09 02:34:46 -07002878/**
Tejun Heo401a8d02010-09-16 10:36:00 +02002879 * cancel_work_sync - cancel a work and wait for it to finish
2880 * @work: the work to cancel
Oleg Nesterov6e84d642007-05-09 02:34:46 -07002881 *
Tejun Heo401a8d02010-09-16 10:36:00 +02002882 * Cancel @work and wait for its execution to finish. This function
2883 * can be used even if the work re-queues itself or migrates to
2884 * another workqueue. On return from this function, @work is
2885 * guaranteed to be not pending or executing on any CPU.
Oleg Nesterov1f1f6422007-07-15 23:41:44 -07002886 *
Tejun Heo401a8d02010-09-16 10:36:00 +02002887 * cancel_work_sync(&delayed_work->work) must not be used for
2888 * delayed_work's. Use cancel_delayed_work_sync() instead.
Oleg Nesterov6e84d642007-05-09 02:34:46 -07002889 *
Tejun Heo401a8d02010-09-16 10:36:00 +02002890 * The caller must ensure that the workqueue on which @work was last
Oleg Nesterov6e84d642007-05-09 02:34:46 -07002891 * queued can't be destroyed before this function returns.
Tejun Heo401a8d02010-09-16 10:36:00 +02002892 *
Yacine Belkadid185af32013-07-31 14:59:24 -07002893 * Return:
Tejun Heo401a8d02010-09-16 10:36:00 +02002894 * %true if @work was pending, %false otherwise.
Oleg Nesterov6e84d642007-05-09 02:34:46 -07002895 */
Tejun Heo401a8d02010-09-16 10:36:00 +02002896bool cancel_work_sync(struct work_struct *work)
Oleg Nesterov6e84d642007-05-09 02:34:46 -07002897{
Tejun Heo36e227d2012-08-03 10:30:46 -07002898 return __cancel_work_timer(work, false);
Oleg Nesterovb89deed2007-05-09 02:33:52 -07002899}
Oleg Nesterov28e53bd2007-05-09 02:34:22 -07002900EXPORT_SYMBOL_GPL(cancel_work_sync);
Oleg Nesterovb89deed2007-05-09 02:33:52 -07002901
Oleg Nesterov6e84d642007-05-09 02:34:46 -07002902/**
Tejun Heo401a8d02010-09-16 10:36:00 +02002903 * flush_delayed_work - wait for a dwork to finish executing the last queueing
2904 * @dwork: the delayed work to flush
Oleg Nesterov6e84d642007-05-09 02:34:46 -07002905 *
Tejun Heo401a8d02010-09-16 10:36:00 +02002906 * Delayed timer is cancelled and the pending work is queued for
2907 * immediate execution. Like flush_work(), this function only
2908 * considers the last queueing instance of @dwork.
Oleg Nesterov1f1f6422007-07-15 23:41:44 -07002909 *
Yacine Belkadid185af32013-07-31 14:59:24 -07002910 * Return:
Tejun Heo401a8d02010-09-16 10:36:00 +02002911 * %true if flush_work() waited for the work to finish execution,
2912 * %false if it was already idle.
Oleg Nesterov6e84d642007-05-09 02:34:46 -07002913 */
Tejun Heo401a8d02010-09-16 10:36:00 +02002914bool flush_delayed_work(struct delayed_work *dwork)
2915{
Tejun Heo8930cab2012-08-03 10:30:45 -07002916 local_irq_disable();
Tejun Heo401a8d02010-09-16 10:36:00 +02002917 if (del_timer_sync(&dwork->timer))
Lai Jiangshan60c057b2013-02-06 18:04:53 -08002918 __queue_work(dwork->cpu, dwork->wq, &dwork->work);
Tejun Heo8930cab2012-08-03 10:30:45 -07002919 local_irq_enable();
Tejun Heo401a8d02010-09-16 10:36:00 +02002920 return flush_work(&dwork->work);
2921}
2922EXPORT_SYMBOL(flush_delayed_work);
2923
2924/**
Tejun Heo57b30ae2012-08-21 13:18:24 -07002925 * cancel_delayed_work - cancel a delayed work
2926 * @dwork: delayed_work to cancel
Tejun Heo09383492010-09-16 10:48:29 +02002927 *
Yacine Belkadid185af32013-07-31 14:59:24 -07002928 * Kill off a pending delayed_work.
2929 *
2930 * Return: %true if @dwork was pending and canceled; %false if it wasn't
2931 * pending.
2932 *
2933 * Note:
2934 * The work callback function may still be running on return, unless
2935 * it returns %true and the work doesn't re-arm itself. Explicitly flush or
2936 * use cancel_delayed_work_sync() to wait on it.
Tejun Heo09383492010-09-16 10:48:29 +02002937 *
Tejun Heo57b30ae2012-08-21 13:18:24 -07002938 * This function is safe to call from any context including IRQ handler.
Tejun Heo09383492010-09-16 10:48:29 +02002939 */
Tejun Heo57b30ae2012-08-21 13:18:24 -07002940bool cancel_delayed_work(struct delayed_work *dwork)
Tejun Heo09383492010-09-16 10:48:29 +02002941{
Tejun Heo57b30ae2012-08-21 13:18:24 -07002942 unsigned long flags;
2943 int ret;
2944
2945 do {
2946 ret = try_to_grab_pending(&dwork->work, true, &flags);
2947 } while (unlikely(ret == -EAGAIN));
2948
2949 if (unlikely(ret < 0))
2950 return false;
2951
Tejun Heo7c3eed52013-01-24 11:01:33 -08002952 set_work_pool_and_clear_pending(&dwork->work,
2953 get_work_pool_id(&dwork->work));
Tejun Heo57b30ae2012-08-21 13:18:24 -07002954 local_irq_restore(flags);
Dan Magenheimerc0158ca2012-10-18 16:31:37 -07002955 return ret;
Tejun Heo09383492010-09-16 10:48:29 +02002956}
Tejun Heo57b30ae2012-08-21 13:18:24 -07002957EXPORT_SYMBOL(cancel_delayed_work);
Tejun Heo09383492010-09-16 10:48:29 +02002958
2959/**
Tejun Heo401a8d02010-09-16 10:36:00 +02002960 * cancel_delayed_work_sync - cancel a delayed work and wait for it to finish
2961 * @dwork: the delayed work cancel
2962 *
2963 * This is cancel_work_sync() for delayed works.
2964 *
Yacine Belkadid185af32013-07-31 14:59:24 -07002965 * Return:
Tejun Heo401a8d02010-09-16 10:36:00 +02002966 * %true if @dwork was pending, %false otherwise.
2967 */
2968bool cancel_delayed_work_sync(struct delayed_work *dwork)
Oleg Nesterov6e84d642007-05-09 02:34:46 -07002969{
Tejun Heo36e227d2012-08-03 10:30:46 -07002970 return __cancel_work_timer(&dwork->work, true);
Oleg Nesterov6e84d642007-05-09 02:34:46 -07002971}
Oleg Nesterovf5a421a2007-07-15 23:41:44 -07002972EXPORT_SYMBOL(cancel_delayed_work_sync);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002973
Rolf Eike Beer0fcb78c2006-07-30 03:03:42 -07002974/**
Tejun Heo31ddd872010-10-19 11:14:49 +02002975 * schedule_on_each_cpu - execute a function synchronously on each online CPU
Andrew Mortonb6136772006-06-25 05:47:49 -07002976 * @func: the function to call
Andrew Mortonb6136772006-06-25 05:47:49 -07002977 *
Tejun Heo31ddd872010-10-19 11:14:49 +02002978 * schedule_on_each_cpu() executes @func on each online CPU using the
2979 * system workqueue and blocks until all CPUs have completed.
Andrew Mortonb6136772006-06-25 05:47:49 -07002980 * schedule_on_each_cpu() is very slow.
Tejun Heo31ddd872010-10-19 11:14:49 +02002981 *
Yacine Belkadid185af32013-07-31 14:59:24 -07002982 * Return:
Tejun Heo31ddd872010-10-19 11:14:49 +02002983 * 0 on success, -errno on failure.
Andrew Mortonb6136772006-06-25 05:47:49 -07002984 */
David Howells65f27f32006-11-22 14:55:48 +00002985int schedule_on_each_cpu(work_func_t func)
Christoph Lameter15316ba2006-01-08 01:00:43 -08002986{
2987 int cpu;
Namhyung Kim38f51562010-08-08 14:24:09 +02002988 struct work_struct __percpu *works;
Christoph Lameter15316ba2006-01-08 01:00:43 -08002989
Andrew Mortonb6136772006-06-25 05:47:49 -07002990 works = alloc_percpu(struct work_struct);
2991 if (!works)
Christoph Lameter15316ba2006-01-08 01:00:43 -08002992 return -ENOMEM;
Andrew Mortonb6136772006-06-25 05:47:49 -07002993
Gautham R Shenoy95402b32008-01-25 21:08:02 +01002994 get_online_cpus();
Tejun Heo93981802009-11-17 14:06:20 -08002995
Christoph Lameter15316ba2006-01-08 01:00:43 -08002996 for_each_online_cpu(cpu) {
Ingo Molnar9bfb1832006-12-18 20:05:09 +01002997 struct work_struct *work = per_cpu_ptr(works, cpu);
2998
2999 INIT_WORK(work, func);
Tejun Heob71ab8c2010-06-29 10:07:14 +02003000 schedule_work_on(cpu, work);
Andi Kleen65a64462009-10-14 06:22:47 +02003001 }
Tejun Heo93981802009-11-17 14:06:20 -08003002
3003 for_each_online_cpu(cpu)
3004 flush_work(per_cpu_ptr(works, cpu));
3005
Gautham R Shenoy95402b32008-01-25 21:08:02 +01003006 put_online_cpus();
Andrew Mortonb6136772006-06-25 05:47:49 -07003007 free_percpu(works);
Christoph Lameter15316ba2006-01-08 01:00:43 -08003008 return 0;
3009}
3010
Alan Sterneef6a7d2010-02-12 17:39:21 +09003011/**
3012 * flush_scheduled_work - ensure that any scheduled work has run to completion.
3013 *
3014 * Forces execution of the kernel-global workqueue and blocks until its
3015 * completion.
3016 *
3017 * Think twice before calling this function! It's very easy to get into
3018 * trouble if you don't take great care. Either of the following situations
3019 * will lead to deadlock:
3020 *
3021 * One of the work items currently on the workqueue needs to acquire
3022 * a lock held by your code or its caller.
3023 *
3024 * Your code is running in the context of a work routine.
3025 *
3026 * They will be detected by lockdep when they occur, but the first might not
3027 * occur very often. It depends on what work items are on the workqueue and
3028 * what locks they need, which you have no control over.
3029 *
3030 * In most situations flushing the entire workqueue is overkill; you merely
3031 * need to know that a particular work item isn't queued and isn't running.
3032 * In such cases you should use cancel_delayed_work_sync() or
3033 * cancel_work_sync() instead.
3034 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07003035void flush_scheduled_work(void)
3036{
Tejun Heod320c032010-06-29 10:07:14 +02003037 flush_workqueue(system_wq);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003038}
Dave Jonesae90dd52006-06-30 01:40:45 -04003039EXPORT_SYMBOL(flush_scheduled_work);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003040
3041/**
James Bottomley1fa44ec2006-02-23 12:43:43 -06003042 * execute_in_process_context - reliably execute the routine with user context
3043 * @fn: the function to execute
James Bottomley1fa44ec2006-02-23 12:43:43 -06003044 * @ew: guaranteed storage for the execute work structure (must
3045 * be available when the work executes)
3046 *
3047 * Executes the function immediately if process context is available,
3048 * otherwise schedules the function for delayed execution.
3049 *
Yacine Belkadid185af32013-07-31 14:59:24 -07003050 * Return: 0 - function was executed
James Bottomley1fa44ec2006-02-23 12:43:43 -06003051 * 1 - function was scheduled for execution
3052 */
David Howells65f27f32006-11-22 14:55:48 +00003053int execute_in_process_context(work_func_t fn, struct execute_work *ew)
James Bottomley1fa44ec2006-02-23 12:43:43 -06003054{
3055 if (!in_interrupt()) {
David Howells65f27f32006-11-22 14:55:48 +00003056 fn(&ew->work);
James Bottomley1fa44ec2006-02-23 12:43:43 -06003057 return 0;
3058 }
3059
David Howells65f27f32006-11-22 14:55:48 +00003060 INIT_WORK(&ew->work, fn);
James Bottomley1fa44ec2006-02-23 12:43:43 -06003061 schedule_work(&ew->work);
3062
3063 return 1;
3064}
3065EXPORT_SYMBOL_GPL(execute_in_process_context);
3066
Tejun Heo226223a2013-03-12 11:30:05 -07003067#ifdef CONFIG_SYSFS
3068/*
3069 * Workqueues with WQ_SYSFS flag set is visible to userland via
3070 * /sys/bus/workqueue/devices/WQ_NAME. All visible workqueues have the
3071 * following attributes.
3072 *
3073 * per_cpu RO bool : whether the workqueue is per-cpu or unbound
3074 * max_active RW int : maximum number of in-flight work items
3075 *
3076 * Unbound workqueues have the following extra attributes.
3077 *
3078 * id RO int : the associated pool ID
3079 * nice RW int : nice value of the workers
3080 * cpumask RW mask : bitmask of allowed CPUs for the workers
3081 */
3082struct wq_device {
3083 struct workqueue_struct *wq;
3084 struct device dev;
3085};
3086
3087static struct workqueue_struct *dev_to_wq(struct device *dev)
3088{
3089 struct wq_device *wq_dev = container_of(dev, struct wq_device, dev);
3090
3091 return wq_dev->wq;
3092}
3093
Greg Kroah-Hartman1a6661d2013-08-23 14:24:41 -07003094static ssize_t per_cpu_show(struct device *dev, struct device_attribute *attr,
3095 char *buf)
Tejun Heo226223a2013-03-12 11:30:05 -07003096{
3097 struct workqueue_struct *wq = dev_to_wq(dev);
3098
3099 return scnprintf(buf, PAGE_SIZE, "%d\n", (bool)!(wq->flags & WQ_UNBOUND));
3100}
Greg Kroah-Hartman1a6661d2013-08-23 14:24:41 -07003101static DEVICE_ATTR_RO(per_cpu);
Tejun Heo226223a2013-03-12 11:30:05 -07003102
Greg Kroah-Hartman1a6661d2013-08-23 14:24:41 -07003103static ssize_t max_active_show(struct device *dev,
3104 struct device_attribute *attr, char *buf)
Tejun Heo226223a2013-03-12 11:30:05 -07003105{
3106 struct workqueue_struct *wq = dev_to_wq(dev);
3107
3108 return scnprintf(buf, PAGE_SIZE, "%d\n", wq->saved_max_active);
3109}
3110
Greg Kroah-Hartman1a6661d2013-08-23 14:24:41 -07003111static ssize_t max_active_store(struct device *dev,
3112 struct device_attribute *attr, const char *buf,
3113 size_t count)
Tejun Heo226223a2013-03-12 11:30:05 -07003114{
3115 struct workqueue_struct *wq = dev_to_wq(dev);
3116 int val;
3117
3118 if (sscanf(buf, "%d", &val) != 1 || val <= 0)
3119 return -EINVAL;
3120
3121 workqueue_set_max_active(wq, val);
3122 return count;
3123}
Greg Kroah-Hartman1a6661d2013-08-23 14:24:41 -07003124static DEVICE_ATTR_RW(max_active);
Tejun Heo226223a2013-03-12 11:30:05 -07003125
Greg Kroah-Hartman1a6661d2013-08-23 14:24:41 -07003126static struct attribute *wq_sysfs_attrs[] = {
3127 &dev_attr_per_cpu.attr,
3128 &dev_attr_max_active.attr,
3129 NULL,
Tejun Heo226223a2013-03-12 11:30:05 -07003130};
Greg Kroah-Hartman1a6661d2013-08-23 14:24:41 -07003131ATTRIBUTE_GROUPS(wq_sysfs);
Tejun Heo226223a2013-03-12 11:30:05 -07003132
Tejun Heod55262c2013-04-01 11:23:38 -07003133static ssize_t wq_pool_ids_show(struct device *dev,
3134 struct device_attribute *attr, char *buf)
Tejun Heo226223a2013-03-12 11:30:05 -07003135{
3136 struct workqueue_struct *wq = dev_to_wq(dev);
Tejun Heod55262c2013-04-01 11:23:38 -07003137 const char *delim = "";
3138 int node, written = 0;
Tejun Heo226223a2013-03-12 11:30:05 -07003139
3140 rcu_read_lock_sched();
Tejun Heod55262c2013-04-01 11:23:38 -07003141 for_each_node(node) {
3142 written += scnprintf(buf + written, PAGE_SIZE - written,
3143 "%s%d:%d", delim, node,
3144 unbound_pwq_by_node(wq, node)->pool->id);
3145 delim = " ";
3146 }
3147 written += scnprintf(buf + written, PAGE_SIZE - written, "\n");
Tejun Heo226223a2013-03-12 11:30:05 -07003148 rcu_read_unlock_sched();
3149
3150 return written;
3151}
3152
3153static ssize_t wq_nice_show(struct device *dev, struct device_attribute *attr,
3154 char *buf)
3155{
3156 struct workqueue_struct *wq = dev_to_wq(dev);
3157 int written;
3158
Tejun Heo6029a912013-04-01 11:23:34 -07003159 mutex_lock(&wq->mutex);
3160 written = scnprintf(buf, PAGE_SIZE, "%d\n", wq->unbound_attrs->nice);
3161 mutex_unlock(&wq->mutex);
Tejun Heo226223a2013-03-12 11:30:05 -07003162
3163 return written;
3164}
3165
3166/* prepare workqueue_attrs for sysfs store operations */
3167static struct workqueue_attrs *wq_sysfs_prep_attrs(struct workqueue_struct *wq)
3168{
3169 struct workqueue_attrs *attrs;
3170
3171 attrs = alloc_workqueue_attrs(GFP_KERNEL);
3172 if (!attrs)
3173 return NULL;
3174
Tejun Heo6029a912013-04-01 11:23:34 -07003175 mutex_lock(&wq->mutex);
3176 copy_workqueue_attrs(attrs, wq->unbound_attrs);
3177 mutex_unlock(&wq->mutex);
Tejun Heo226223a2013-03-12 11:30:05 -07003178 return attrs;
3179}
3180
3181static ssize_t wq_nice_store(struct device *dev, struct device_attribute *attr,
3182 const char *buf, size_t count)
3183{
3184 struct workqueue_struct *wq = dev_to_wq(dev);
3185 struct workqueue_attrs *attrs;
3186 int ret;
3187
3188 attrs = wq_sysfs_prep_attrs(wq);
3189 if (!attrs)
3190 return -ENOMEM;
3191
3192 if (sscanf(buf, "%d", &attrs->nice) == 1 &&
Dongsheng Yang14481842014-02-11 15:34:52 +08003193 attrs->nice >= MIN_NICE && attrs->nice <= MAX_NICE)
Tejun Heo226223a2013-03-12 11:30:05 -07003194 ret = apply_workqueue_attrs(wq, attrs);
3195 else
3196 ret = -EINVAL;
3197
3198 free_workqueue_attrs(attrs);
3199 return ret ?: count;
3200}
3201
3202static ssize_t wq_cpumask_show(struct device *dev,
3203 struct device_attribute *attr, char *buf)
3204{
3205 struct workqueue_struct *wq = dev_to_wq(dev);
3206 int written;
3207
Tejun Heo6029a912013-04-01 11:23:34 -07003208 mutex_lock(&wq->mutex);
3209 written = cpumask_scnprintf(buf, PAGE_SIZE, wq->unbound_attrs->cpumask);
3210 mutex_unlock(&wq->mutex);
Tejun Heo226223a2013-03-12 11:30:05 -07003211
3212 written += scnprintf(buf + written, PAGE_SIZE - written, "\n");
3213 return written;
3214}
3215
3216static ssize_t wq_cpumask_store(struct device *dev,
3217 struct device_attribute *attr,
3218 const char *buf, size_t count)
3219{
3220 struct workqueue_struct *wq = dev_to_wq(dev);
3221 struct workqueue_attrs *attrs;
3222 int ret;
3223
3224 attrs = wq_sysfs_prep_attrs(wq);
3225 if (!attrs)
3226 return -ENOMEM;
3227
3228 ret = cpumask_parse(buf, attrs->cpumask);
3229 if (!ret)
3230 ret = apply_workqueue_attrs(wq, attrs);
3231
3232 free_workqueue_attrs(attrs);
3233 return ret ?: count;
3234}
3235
Tejun Heod55262c2013-04-01 11:23:38 -07003236static ssize_t wq_numa_show(struct device *dev, struct device_attribute *attr,
3237 char *buf)
3238{
3239 struct workqueue_struct *wq = dev_to_wq(dev);
3240 int written;
3241
3242 mutex_lock(&wq->mutex);
3243 written = scnprintf(buf, PAGE_SIZE, "%d\n",
3244 !wq->unbound_attrs->no_numa);
3245 mutex_unlock(&wq->mutex);
3246
3247 return written;
3248}
3249
3250static ssize_t wq_numa_store(struct device *dev, struct device_attribute *attr,
3251 const char *buf, size_t count)
3252{
3253 struct workqueue_struct *wq = dev_to_wq(dev);
3254 struct workqueue_attrs *attrs;
3255 int v, ret;
3256
3257 attrs = wq_sysfs_prep_attrs(wq);
3258 if (!attrs)
3259 return -ENOMEM;
3260
3261 ret = -EINVAL;
3262 if (sscanf(buf, "%d", &v) == 1) {
3263 attrs->no_numa = !v;
3264 ret = apply_workqueue_attrs(wq, attrs);
3265 }
3266
3267 free_workqueue_attrs(attrs);
3268 return ret ?: count;
3269}
3270
Tejun Heo226223a2013-03-12 11:30:05 -07003271static struct device_attribute wq_sysfs_unbound_attrs[] = {
Tejun Heod55262c2013-04-01 11:23:38 -07003272 __ATTR(pool_ids, 0444, wq_pool_ids_show, NULL),
Tejun Heo226223a2013-03-12 11:30:05 -07003273 __ATTR(nice, 0644, wq_nice_show, wq_nice_store),
3274 __ATTR(cpumask, 0644, wq_cpumask_show, wq_cpumask_store),
Tejun Heod55262c2013-04-01 11:23:38 -07003275 __ATTR(numa, 0644, wq_numa_show, wq_numa_store),
Tejun Heo226223a2013-03-12 11:30:05 -07003276 __ATTR_NULL,
3277};
3278
3279static struct bus_type wq_subsys = {
3280 .name = "workqueue",
Greg Kroah-Hartman1a6661d2013-08-23 14:24:41 -07003281 .dev_groups = wq_sysfs_groups,
Tejun Heo226223a2013-03-12 11:30:05 -07003282};
3283
3284static int __init wq_sysfs_init(void)
3285{
3286 return subsys_virtual_register(&wq_subsys, NULL);
3287}
3288core_initcall(wq_sysfs_init);
3289
3290static void wq_device_release(struct device *dev)
3291{
3292 struct wq_device *wq_dev = container_of(dev, struct wq_device, dev);
3293
3294 kfree(wq_dev);
3295}
3296
3297/**
3298 * workqueue_sysfs_register - make a workqueue visible in sysfs
3299 * @wq: the workqueue to register
3300 *
3301 * Expose @wq in sysfs under /sys/bus/workqueue/devices.
3302 * alloc_workqueue*() automatically calls this function if WQ_SYSFS is set
3303 * which is the preferred method.
3304 *
3305 * Workqueue user should use this function directly iff it wants to apply
3306 * workqueue_attrs before making the workqueue visible in sysfs; otherwise,
3307 * apply_workqueue_attrs() may race against userland updating the
3308 * attributes.
3309 *
Yacine Belkadid185af32013-07-31 14:59:24 -07003310 * Return: 0 on success, -errno on failure.
Tejun Heo226223a2013-03-12 11:30:05 -07003311 */
3312int workqueue_sysfs_register(struct workqueue_struct *wq)
3313{
3314 struct wq_device *wq_dev;
3315 int ret;
3316
3317 /*
3318 * Adjusting max_active or creating new pwqs by applyting
3319 * attributes breaks ordering guarantee. Disallow exposing ordered
3320 * workqueues.
3321 */
3322 if (WARN_ON(wq->flags & __WQ_ORDERED))
3323 return -EINVAL;
3324
3325 wq->wq_dev = wq_dev = kzalloc(sizeof(*wq_dev), GFP_KERNEL);
3326 if (!wq_dev)
3327 return -ENOMEM;
3328
3329 wq_dev->wq = wq;
3330 wq_dev->dev.bus = &wq_subsys;
3331 wq_dev->dev.init_name = wq->name;
3332 wq_dev->dev.release = wq_device_release;
3333
3334 /*
3335 * unbound_attrs are created separately. Suppress uevent until
3336 * everything is ready.
3337 */
3338 dev_set_uevent_suppress(&wq_dev->dev, true);
3339
3340 ret = device_register(&wq_dev->dev);
3341 if (ret) {
3342 kfree(wq_dev);
3343 wq->wq_dev = NULL;
3344 return ret;
3345 }
3346
3347 if (wq->flags & WQ_UNBOUND) {
3348 struct device_attribute *attr;
3349
3350 for (attr = wq_sysfs_unbound_attrs; attr->attr.name; attr++) {
3351 ret = device_create_file(&wq_dev->dev, attr);
3352 if (ret) {
3353 device_unregister(&wq_dev->dev);
3354 wq->wq_dev = NULL;
3355 return ret;
3356 }
3357 }
3358 }
3359
3360 kobject_uevent(&wq_dev->dev.kobj, KOBJ_ADD);
3361 return 0;
3362}
3363
3364/**
3365 * workqueue_sysfs_unregister - undo workqueue_sysfs_register()
3366 * @wq: the workqueue to unregister
3367 *
3368 * If @wq is registered to sysfs by workqueue_sysfs_register(), unregister.
3369 */
3370static void workqueue_sysfs_unregister(struct workqueue_struct *wq)
3371{
3372 struct wq_device *wq_dev = wq->wq_dev;
3373
3374 if (!wq->wq_dev)
3375 return;
3376
3377 wq->wq_dev = NULL;
3378 device_unregister(&wq_dev->dev);
3379}
3380#else /* CONFIG_SYSFS */
3381static void workqueue_sysfs_unregister(struct workqueue_struct *wq) { }
3382#endif /* CONFIG_SYSFS */
3383
Tejun Heo7a4e3442013-03-12 11:30:00 -07003384/**
3385 * free_workqueue_attrs - free a workqueue_attrs
3386 * @attrs: workqueue_attrs to free
3387 *
3388 * Undo alloc_workqueue_attrs().
3389 */
3390void free_workqueue_attrs(struct workqueue_attrs *attrs)
3391{
3392 if (attrs) {
3393 free_cpumask_var(attrs->cpumask);
3394 kfree(attrs);
3395 }
3396}
3397
3398/**
3399 * alloc_workqueue_attrs - allocate a workqueue_attrs
3400 * @gfp_mask: allocation mask to use
3401 *
3402 * Allocate a new workqueue_attrs, initialize with default settings and
Yacine Belkadid185af32013-07-31 14:59:24 -07003403 * return it.
3404 *
3405 * Return: The allocated new workqueue_attr on success. %NULL on failure.
Tejun Heo7a4e3442013-03-12 11:30:00 -07003406 */
3407struct workqueue_attrs *alloc_workqueue_attrs(gfp_t gfp_mask)
3408{
3409 struct workqueue_attrs *attrs;
3410
3411 attrs = kzalloc(sizeof(*attrs), gfp_mask);
3412 if (!attrs)
3413 goto fail;
3414 if (!alloc_cpumask_var(&attrs->cpumask, gfp_mask))
3415 goto fail;
3416
Tejun Heo13e2e552013-04-01 11:23:31 -07003417 cpumask_copy(attrs->cpumask, cpu_possible_mask);
Tejun Heo7a4e3442013-03-12 11:30:00 -07003418 return attrs;
3419fail:
3420 free_workqueue_attrs(attrs);
3421 return NULL;
3422}
3423
Tejun Heo29c91e92013-03-12 11:30:03 -07003424static void copy_workqueue_attrs(struct workqueue_attrs *to,
3425 const struct workqueue_attrs *from)
3426{
3427 to->nice = from->nice;
3428 cpumask_copy(to->cpumask, from->cpumask);
Shaohua Li2865a8f2013-08-01 09:56:36 +08003429 /*
3430 * Unlike hash and equality test, this function doesn't ignore
3431 * ->no_numa as it is used for both pool and wq attrs. Instead,
3432 * get_unbound_pool() explicitly clears ->no_numa after copying.
3433 */
3434 to->no_numa = from->no_numa;
Tejun Heo29c91e92013-03-12 11:30:03 -07003435}
3436
Tejun Heo29c91e92013-03-12 11:30:03 -07003437/* hash value of the content of @attr */
3438static u32 wqattrs_hash(const struct workqueue_attrs *attrs)
3439{
3440 u32 hash = 0;
3441
3442 hash = jhash_1word(attrs->nice, hash);
Tejun Heo13e2e552013-04-01 11:23:31 -07003443 hash = jhash(cpumask_bits(attrs->cpumask),
3444 BITS_TO_LONGS(nr_cpumask_bits) * sizeof(long), hash);
Tejun Heo29c91e92013-03-12 11:30:03 -07003445 return hash;
3446}
3447
3448/* content equality test */
3449static bool wqattrs_equal(const struct workqueue_attrs *a,
3450 const struct workqueue_attrs *b)
3451{
3452 if (a->nice != b->nice)
3453 return false;
3454 if (!cpumask_equal(a->cpumask, b->cpumask))
3455 return false;
3456 return true;
3457}
3458
Tejun Heo7a4e3442013-03-12 11:30:00 -07003459/**
3460 * init_worker_pool - initialize a newly zalloc'd worker_pool
3461 * @pool: worker_pool to initialize
3462 *
3463 * Initiailize a newly zalloc'd @pool. It also allocates @pool->attrs.
Yacine Belkadid185af32013-07-31 14:59:24 -07003464 *
3465 * Return: 0 on success, -errno on failure. Even on failure, all fields
Tejun Heo29c91e92013-03-12 11:30:03 -07003466 * inside @pool proper are initialized and put_unbound_pool() can be called
3467 * on @pool safely to release it.
Tejun Heo7a4e3442013-03-12 11:30:00 -07003468 */
3469static int init_worker_pool(struct worker_pool *pool)
Tejun Heo4e1a1f92013-03-12 11:30:00 -07003470{
3471 spin_lock_init(&pool->lock);
Tejun Heo29c91e92013-03-12 11:30:03 -07003472 pool->id = -1;
3473 pool->cpu = -1;
Tejun Heof3f90ad2013-04-01 11:23:34 -07003474 pool->node = NUMA_NO_NODE;
Tejun Heo4e1a1f92013-03-12 11:30:00 -07003475 pool->flags |= POOL_DISASSOCIATED;
3476 INIT_LIST_HEAD(&pool->worklist);
3477 INIT_LIST_HEAD(&pool->idle_list);
3478 hash_init(pool->busy_hash);
3479
3480 init_timer_deferrable(&pool->idle_timer);
3481 pool->idle_timer.function = idle_worker_timeout;
3482 pool->idle_timer.data = (unsigned long)pool;
3483
3484 setup_timer(&pool->mayday_timer, pool_mayday_timeout,
3485 (unsigned long)pool);
3486
3487 mutex_init(&pool->manager_arb);
Tejun Heobc3a1af2013-03-13 19:47:39 -07003488 mutex_init(&pool->manager_mutex);
Tejun Heo822d8402013-03-19 13:45:21 -07003489 idr_init(&pool->worker_idr);
Lai Jiangshanda028462014-05-20 17:46:31 +08003490 INIT_LIST_HEAD(&pool->workers);
Tejun Heo7a4e3442013-03-12 11:30:00 -07003491
Tejun Heo29c91e92013-03-12 11:30:03 -07003492 INIT_HLIST_NODE(&pool->hash_node);
3493 pool->refcnt = 1;
3494
3495 /* shouldn't fail above this point */
Tejun Heo7a4e3442013-03-12 11:30:00 -07003496 pool->attrs = alloc_workqueue_attrs(GFP_KERNEL);
3497 if (!pool->attrs)
3498 return -ENOMEM;
3499 return 0;
Tejun Heo4e1a1f92013-03-12 11:30:00 -07003500}
3501
Tejun Heo29c91e92013-03-12 11:30:03 -07003502static void rcu_free_pool(struct rcu_head *rcu)
3503{
3504 struct worker_pool *pool = container_of(rcu, struct worker_pool, rcu);
3505
Tejun Heo822d8402013-03-19 13:45:21 -07003506 idr_destroy(&pool->worker_idr);
Tejun Heo29c91e92013-03-12 11:30:03 -07003507 free_workqueue_attrs(pool->attrs);
3508 kfree(pool);
3509}
3510
3511/**
3512 * put_unbound_pool - put a worker_pool
3513 * @pool: worker_pool to put
3514 *
3515 * Put @pool. If its refcnt reaches zero, it gets destroyed in sched-RCU
Tejun Heoc5aa87b2013-03-13 16:51:36 -07003516 * safe manner. get_unbound_pool() calls this function on its failure path
3517 * and this function should be able to release pools which went through,
3518 * successfully or not, init_worker_pool().
Tejun Heoa892cac2013-04-01 11:23:32 -07003519 *
3520 * Should be called with wq_pool_mutex held.
Tejun Heo29c91e92013-03-12 11:30:03 -07003521 */
3522static void put_unbound_pool(struct worker_pool *pool)
3523{
Lai Jiangshan60f5a4b2014-05-20 17:46:29 +08003524 DECLARE_COMPLETION_ONSTACK(detach_completion);
Tejun Heo29c91e92013-03-12 11:30:03 -07003525 struct worker *worker;
3526
Tejun Heoa892cac2013-04-01 11:23:32 -07003527 lockdep_assert_held(&wq_pool_mutex);
3528
3529 if (--pool->refcnt)
Tejun Heo29c91e92013-03-12 11:30:03 -07003530 return;
Tejun Heo29c91e92013-03-12 11:30:03 -07003531
3532 /* sanity checks */
3533 if (WARN_ON(!(pool->flags & POOL_DISASSOCIATED)) ||
Tejun Heoa892cac2013-04-01 11:23:32 -07003534 WARN_ON(!list_empty(&pool->worklist)))
Tejun Heo29c91e92013-03-12 11:30:03 -07003535 return;
Tejun Heo29c91e92013-03-12 11:30:03 -07003536
3537 /* release id and unhash */
3538 if (pool->id >= 0)
3539 idr_remove(&worker_pool_idr, pool->id);
3540 hash_del(&pool->hash_node);
3541
Tejun Heoc5aa87b2013-03-13 16:51:36 -07003542 /*
3543 * Become the manager and destroy all workers. Grabbing
3544 * manager_arb prevents @pool's workers from blocking on
3545 * manager_mutex.
3546 */
Tejun Heo29c91e92013-03-12 11:30:03 -07003547 mutex_lock(&pool->manager_arb);
Tejun Heo29c91e92013-03-12 11:30:03 -07003548
Lai Jiangshan60f5a4b2014-05-20 17:46:29 +08003549 spin_lock_irq(&pool->lock);
Tejun Heo29c91e92013-03-12 11:30:03 -07003550 while ((worker = first_worker(pool)))
3551 destroy_worker(worker);
3552 WARN_ON(pool->nr_workers || pool->nr_idle);
Tejun Heo29c91e92013-03-12 11:30:03 -07003553 spin_unlock_irq(&pool->lock);
Lai Jiangshan60f5a4b2014-05-20 17:46:29 +08003554
3555 mutex_lock(&pool->manager_mutex);
Lai Jiangshanda028462014-05-20 17:46:31 +08003556 if (!list_empty(&pool->workers))
Lai Jiangshan60f5a4b2014-05-20 17:46:29 +08003557 pool->detach_completion = &detach_completion;
Tejun Heocd549682013-03-13 19:47:39 -07003558 mutex_unlock(&pool->manager_mutex);
Lai Jiangshan60f5a4b2014-05-20 17:46:29 +08003559
3560 if (pool->detach_completion)
3561 wait_for_completion(pool->detach_completion);
3562
Tejun Heo29c91e92013-03-12 11:30:03 -07003563 mutex_unlock(&pool->manager_arb);
3564
3565 /* shut down the timers */
3566 del_timer_sync(&pool->idle_timer);
3567 del_timer_sync(&pool->mayday_timer);
3568
3569 /* sched-RCU protected to allow dereferences from get_work_pool() */
3570 call_rcu_sched(&pool->rcu, rcu_free_pool);
3571}
3572
3573/**
3574 * get_unbound_pool - get a worker_pool with the specified attributes
3575 * @attrs: the attributes of the worker_pool to get
3576 *
3577 * Obtain a worker_pool which has the same attributes as @attrs, bump the
3578 * reference count and return it. If there already is a matching
3579 * worker_pool, it will be used; otherwise, this function attempts to
Yacine Belkadid185af32013-07-31 14:59:24 -07003580 * create a new one.
Tejun Heoa892cac2013-04-01 11:23:32 -07003581 *
3582 * Should be called with wq_pool_mutex held.
Yacine Belkadid185af32013-07-31 14:59:24 -07003583 *
3584 * Return: On success, a worker_pool with the same attributes as @attrs.
3585 * On failure, %NULL.
Tejun Heo29c91e92013-03-12 11:30:03 -07003586 */
3587static struct worker_pool *get_unbound_pool(const struct workqueue_attrs *attrs)
3588{
Tejun Heo29c91e92013-03-12 11:30:03 -07003589 u32 hash = wqattrs_hash(attrs);
3590 struct worker_pool *pool;
Tejun Heof3f90ad2013-04-01 11:23:34 -07003591 int node;
Tejun Heo29c91e92013-03-12 11:30:03 -07003592
Tejun Heoa892cac2013-04-01 11:23:32 -07003593 lockdep_assert_held(&wq_pool_mutex);
Tejun Heo29c91e92013-03-12 11:30:03 -07003594
3595 /* do we already have a matching pool? */
Tejun Heo29c91e92013-03-12 11:30:03 -07003596 hash_for_each_possible(unbound_pool_hash, pool, hash_node, hash) {
3597 if (wqattrs_equal(pool->attrs, attrs)) {
3598 pool->refcnt++;
3599 goto out_unlock;
3600 }
3601 }
Tejun Heo29c91e92013-03-12 11:30:03 -07003602
3603 /* nope, create a new one */
3604 pool = kzalloc(sizeof(*pool), GFP_KERNEL);
3605 if (!pool || init_worker_pool(pool) < 0)
3606 goto fail;
3607
Lai Jiangshan12ee4fc2013-03-20 03:28:01 +08003608 if (workqueue_freezing)
3609 pool->flags |= POOL_FREEZING;
3610
Tejun Heo8864b4e2013-03-12 11:30:04 -07003611 lockdep_set_subclass(&pool->lock, 1); /* see put_pwq() */
Tejun Heo29c91e92013-03-12 11:30:03 -07003612 copy_workqueue_attrs(pool->attrs, attrs);
3613
Shaohua Li2865a8f2013-08-01 09:56:36 +08003614 /*
3615 * no_numa isn't a worker_pool attribute, always clear it. See
3616 * 'struct workqueue_attrs' comments for detail.
3617 */
3618 pool->attrs->no_numa = false;
3619
Tejun Heof3f90ad2013-04-01 11:23:34 -07003620 /* if cpumask is contained inside a NUMA node, we belong to that node */
3621 if (wq_numa_enabled) {
3622 for_each_node(node) {
3623 if (cpumask_subset(pool->attrs->cpumask,
3624 wq_numa_possible_cpumask[node])) {
3625 pool->node = node;
3626 break;
3627 }
3628 }
3629 }
3630
Tejun Heo29c91e92013-03-12 11:30:03 -07003631 if (worker_pool_assign_id(pool) < 0)
3632 goto fail;
3633
3634 /* create and start the initial worker */
Tejun Heoebf44d12013-03-13 19:47:39 -07003635 if (create_and_start_worker(pool) < 0)
Tejun Heo29c91e92013-03-12 11:30:03 -07003636 goto fail;
3637
Tejun Heo29c91e92013-03-12 11:30:03 -07003638 /* install */
Tejun Heo29c91e92013-03-12 11:30:03 -07003639 hash_add(unbound_pool_hash, &pool->hash_node, hash);
3640out_unlock:
Tejun Heo29c91e92013-03-12 11:30:03 -07003641 return pool;
3642fail:
Tejun Heo29c91e92013-03-12 11:30:03 -07003643 if (pool)
3644 put_unbound_pool(pool);
3645 return NULL;
3646}
3647
Tejun Heo8864b4e2013-03-12 11:30:04 -07003648static void rcu_free_pwq(struct rcu_head *rcu)
3649{
3650 kmem_cache_free(pwq_cache,
3651 container_of(rcu, struct pool_workqueue, rcu));
3652}
3653
3654/*
3655 * Scheduled on system_wq by put_pwq() when an unbound pwq hits zero refcnt
3656 * and needs to be destroyed.
3657 */
3658static void pwq_unbound_release_workfn(struct work_struct *work)
3659{
3660 struct pool_workqueue *pwq = container_of(work, struct pool_workqueue,
3661 unbound_release_work);
3662 struct workqueue_struct *wq = pwq->wq;
3663 struct worker_pool *pool = pwq->pool;
Tejun Heobc0caf02013-04-01 11:23:31 -07003664 bool is_last;
Tejun Heo8864b4e2013-03-12 11:30:04 -07003665
3666 if (WARN_ON_ONCE(!(wq->flags & WQ_UNBOUND)))
3667 return;
3668
Tejun Heo75ccf592013-03-12 11:30:04 -07003669 /*
Lai Jiangshan3c25a552013-03-25 16:57:17 -07003670 * Unlink @pwq. Synchronization against wq->mutex isn't strictly
Tejun Heo75ccf592013-03-12 11:30:04 -07003671 * necessary on release but do it anyway. It's easier to verify
3672 * and consistent with the linking path.
3673 */
Lai Jiangshan3c25a552013-03-25 16:57:17 -07003674 mutex_lock(&wq->mutex);
Tejun Heo8864b4e2013-03-12 11:30:04 -07003675 list_del_rcu(&pwq->pwqs_node);
Tejun Heobc0caf02013-04-01 11:23:31 -07003676 is_last = list_empty(&wq->pwqs);
Lai Jiangshan3c25a552013-03-25 16:57:17 -07003677 mutex_unlock(&wq->mutex);
Tejun Heo8864b4e2013-03-12 11:30:04 -07003678
Tejun Heoa892cac2013-04-01 11:23:32 -07003679 mutex_lock(&wq_pool_mutex);
Tejun Heo8864b4e2013-03-12 11:30:04 -07003680 put_unbound_pool(pool);
Tejun Heoa892cac2013-04-01 11:23:32 -07003681 mutex_unlock(&wq_pool_mutex);
3682
Tejun Heo8864b4e2013-03-12 11:30:04 -07003683 call_rcu_sched(&pwq->rcu, rcu_free_pwq);
3684
3685 /*
3686 * If we're the last pwq going away, @wq is already dead and no one
3687 * is gonna access it anymore. Free it.
3688 */
Tejun Heo6029a912013-04-01 11:23:34 -07003689 if (is_last) {
3690 free_workqueue_attrs(wq->unbound_attrs);
Tejun Heo8864b4e2013-03-12 11:30:04 -07003691 kfree(wq);
Tejun Heo6029a912013-04-01 11:23:34 -07003692 }
Tejun Heo8864b4e2013-03-12 11:30:04 -07003693}
3694
Tejun Heo0fbd95a2013-03-13 16:51:35 -07003695/**
Tejun Heo699ce092013-03-13 16:51:35 -07003696 * pwq_adjust_max_active - update a pwq's max_active to the current setting
Tejun Heo0fbd95a2013-03-13 16:51:35 -07003697 * @pwq: target pool_workqueue
Tejun Heo0fbd95a2013-03-13 16:51:35 -07003698 *
Tejun Heo699ce092013-03-13 16:51:35 -07003699 * If @pwq isn't freezing, set @pwq->max_active to the associated
3700 * workqueue's saved_max_active and activate delayed work items
3701 * accordingly. If @pwq is freezing, clear @pwq->max_active to zero.
Tejun Heo0fbd95a2013-03-13 16:51:35 -07003702 */
Tejun Heo699ce092013-03-13 16:51:35 -07003703static void pwq_adjust_max_active(struct pool_workqueue *pwq)
Tejun Heo0fbd95a2013-03-13 16:51:35 -07003704{
Tejun Heo699ce092013-03-13 16:51:35 -07003705 struct workqueue_struct *wq = pwq->wq;
3706 bool freezable = wq->flags & WQ_FREEZABLE;
Tejun Heo0fbd95a2013-03-13 16:51:35 -07003707
Tejun Heo699ce092013-03-13 16:51:35 -07003708 /* for @wq->saved_max_active */
Lai Jiangshana357fc02013-03-25 16:57:19 -07003709 lockdep_assert_held(&wq->mutex);
Tejun Heo699ce092013-03-13 16:51:35 -07003710
3711 /* fast exit for non-freezable wqs */
3712 if (!freezable && pwq->max_active == wq->saved_max_active)
3713 return;
3714
Lai Jiangshana357fc02013-03-25 16:57:19 -07003715 spin_lock_irq(&pwq->pool->lock);
Tejun Heo699ce092013-03-13 16:51:35 -07003716
3717 if (!freezable || !(pwq->pool->flags & POOL_FREEZING)) {
3718 pwq->max_active = wq->saved_max_active;
3719
3720 while (!list_empty(&pwq->delayed_works) &&
3721 pwq->nr_active < pwq->max_active)
3722 pwq_activate_first_delayed(pwq);
Lai Jiangshan951a0782013-03-20 10:52:30 -07003723
3724 /*
3725 * Need to kick a worker after thawed or an unbound wq's
3726 * max_active is bumped. It's a slow path. Do it always.
3727 */
3728 wake_up_worker(pwq->pool);
Tejun Heo699ce092013-03-13 16:51:35 -07003729 } else {
3730 pwq->max_active = 0;
3731 }
3732
Lai Jiangshana357fc02013-03-25 16:57:19 -07003733 spin_unlock_irq(&pwq->pool->lock);
Tejun Heo0fbd95a2013-03-13 16:51:35 -07003734}
3735
Tejun Heoe50aba92013-04-01 11:23:35 -07003736/* initialize newly alloced @pwq which is associated with @wq and @pool */
Tejun Heof147f292013-04-01 11:23:35 -07003737static void init_pwq(struct pool_workqueue *pwq, struct workqueue_struct *wq,
3738 struct worker_pool *pool)
Tejun Heod2c1d402013-03-12 11:30:04 -07003739{
3740 BUG_ON((unsigned long)pwq & WORK_STRUCT_FLAG_MASK);
3741
Tejun Heoe50aba92013-04-01 11:23:35 -07003742 memset(pwq, 0, sizeof(*pwq));
3743
Tejun Heod2c1d402013-03-12 11:30:04 -07003744 pwq->pool = pool;
3745 pwq->wq = wq;
3746 pwq->flush_color = -1;
Tejun Heo8864b4e2013-03-12 11:30:04 -07003747 pwq->refcnt = 1;
Tejun Heod2c1d402013-03-12 11:30:04 -07003748 INIT_LIST_HEAD(&pwq->delayed_works);
Tejun Heo1befcf32013-04-01 11:23:35 -07003749 INIT_LIST_HEAD(&pwq->pwqs_node);
Tejun Heod2c1d402013-03-12 11:30:04 -07003750 INIT_LIST_HEAD(&pwq->mayday_node);
Tejun Heo8864b4e2013-03-12 11:30:04 -07003751 INIT_WORK(&pwq->unbound_release_work, pwq_unbound_release_workfn);
Tejun Heof147f292013-04-01 11:23:35 -07003752}
Tejun Heod2c1d402013-03-12 11:30:04 -07003753
Tejun Heof147f292013-04-01 11:23:35 -07003754/* sync @pwq with the current state of its associated wq and link it */
Tejun Heo1befcf32013-04-01 11:23:35 -07003755static void link_pwq(struct pool_workqueue *pwq)
Tejun Heof147f292013-04-01 11:23:35 -07003756{
3757 struct workqueue_struct *wq = pwq->wq;
3758
3759 lockdep_assert_held(&wq->mutex);
Tejun Heo75ccf592013-03-12 11:30:04 -07003760
Tejun Heo1befcf32013-04-01 11:23:35 -07003761 /* may be called multiple times, ignore if already linked */
3762 if (!list_empty(&pwq->pwqs_node))
3763 return;
3764
Tejun Heo983ca252013-03-13 16:51:35 -07003765 /*
3766 * Set the matching work_color. This is synchronized with
Lai Jiangshan3c25a552013-03-25 16:57:17 -07003767 * wq->mutex to avoid confusing flush_workqueue().
Tejun Heo983ca252013-03-13 16:51:35 -07003768 */
Tejun Heo75ccf592013-03-12 11:30:04 -07003769 pwq->work_color = wq->work_color;
Tejun Heo983ca252013-03-13 16:51:35 -07003770
3771 /* sync max_active to the current setting */
3772 pwq_adjust_max_active(pwq);
3773
3774 /* link in @pwq */
Tejun Heo9e8cd2f2013-03-12 11:30:04 -07003775 list_add_rcu(&pwq->pwqs_node, &wq->pwqs);
Tejun Heof147f292013-04-01 11:23:35 -07003776}
Lai Jiangshana357fc02013-03-25 16:57:19 -07003777
Tejun Heof147f292013-04-01 11:23:35 -07003778/* obtain a pool matching @attr and create a pwq associating the pool and @wq */
3779static struct pool_workqueue *alloc_unbound_pwq(struct workqueue_struct *wq,
3780 const struct workqueue_attrs *attrs)
3781{
3782 struct worker_pool *pool;
3783 struct pool_workqueue *pwq;
3784
3785 lockdep_assert_held(&wq_pool_mutex);
3786
3787 pool = get_unbound_pool(attrs);
3788 if (!pool)
3789 return NULL;
3790
Tejun Heoe50aba92013-04-01 11:23:35 -07003791 pwq = kmem_cache_alloc_node(pwq_cache, GFP_KERNEL, pool->node);
Tejun Heof147f292013-04-01 11:23:35 -07003792 if (!pwq) {
3793 put_unbound_pool(pool);
3794 return NULL;
Tejun Heodf2d5ae2013-04-01 11:23:35 -07003795 }
Tejun Heo6029a912013-04-01 11:23:34 -07003796
Tejun Heof147f292013-04-01 11:23:35 -07003797 init_pwq(pwq, wq, pool);
3798 return pwq;
Tejun Heod2c1d402013-03-12 11:30:04 -07003799}
3800
Tejun Heo4c16bd32013-04-01 11:23:36 -07003801/* undo alloc_unbound_pwq(), used only in the error path */
3802static void free_unbound_pwq(struct pool_workqueue *pwq)
3803{
3804 lockdep_assert_held(&wq_pool_mutex);
3805
3806 if (pwq) {
3807 put_unbound_pool(pwq->pool);
Wei Yongjuncece95d2013-04-09 14:29:11 +08003808 kmem_cache_free(pwq_cache, pwq);
Tejun Heo4c16bd32013-04-01 11:23:36 -07003809 }
3810}
3811
3812/**
3813 * wq_calc_node_mask - calculate a wq_attrs' cpumask for the specified node
3814 * @attrs: the wq_attrs of interest
3815 * @node: the target NUMA node
3816 * @cpu_going_down: if >= 0, the CPU to consider as offline
3817 * @cpumask: outarg, the resulting cpumask
3818 *
3819 * Calculate the cpumask a workqueue with @attrs should use on @node. If
3820 * @cpu_going_down is >= 0, that cpu is considered offline during
Yacine Belkadid185af32013-07-31 14:59:24 -07003821 * calculation. The result is stored in @cpumask.
Tejun Heo4c16bd32013-04-01 11:23:36 -07003822 *
3823 * If NUMA affinity is not enabled, @attrs->cpumask is always used. If
3824 * enabled and @node has online CPUs requested by @attrs, the returned
3825 * cpumask is the intersection of the possible CPUs of @node and
3826 * @attrs->cpumask.
3827 *
3828 * The caller is responsible for ensuring that the cpumask of @node stays
3829 * stable.
Yacine Belkadid185af32013-07-31 14:59:24 -07003830 *
3831 * Return: %true if the resulting @cpumask is different from @attrs->cpumask,
3832 * %false if equal.
Tejun Heo4c16bd32013-04-01 11:23:36 -07003833 */
3834static bool wq_calc_node_cpumask(const struct workqueue_attrs *attrs, int node,
3835 int cpu_going_down, cpumask_t *cpumask)
3836{
Tejun Heod55262c2013-04-01 11:23:38 -07003837 if (!wq_numa_enabled || attrs->no_numa)
Tejun Heo4c16bd32013-04-01 11:23:36 -07003838 goto use_dfl;
3839
3840 /* does @node have any online CPUs @attrs wants? */
3841 cpumask_and(cpumask, cpumask_of_node(node), attrs->cpumask);
3842 if (cpu_going_down >= 0)
3843 cpumask_clear_cpu(cpu_going_down, cpumask);
3844
3845 if (cpumask_empty(cpumask))
3846 goto use_dfl;
3847
3848 /* yeap, return possible CPUs in @node that @attrs wants */
3849 cpumask_and(cpumask, attrs->cpumask, wq_numa_possible_cpumask[node]);
3850 return !cpumask_equal(cpumask, attrs->cpumask);
3851
3852use_dfl:
3853 cpumask_copy(cpumask, attrs->cpumask);
3854 return false;
3855}
3856
Tejun Heo1befcf32013-04-01 11:23:35 -07003857/* install @pwq into @wq's numa_pwq_tbl[] for @node and return the old pwq */
3858static struct pool_workqueue *numa_pwq_tbl_install(struct workqueue_struct *wq,
3859 int node,
3860 struct pool_workqueue *pwq)
3861{
3862 struct pool_workqueue *old_pwq;
3863
3864 lockdep_assert_held(&wq->mutex);
3865
3866 /* link_pwq() can handle duplicate calls */
3867 link_pwq(pwq);
3868
3869 old_pwq = rcu_access_pointer(wq->numa_pwq_tbl[node]);
3870 rcu_assign_pointer(wq->numa_pwq_tbl[node], pwq);
3871 return old_pwq;
3872}
3873
Tejun Heo9e8cd2f2013-03-12 11:30:04 -07003874/**
3875 * apply_workqueue_attrs - apply new workqueue_attrs to an unbound workqueue
3876 * @wq: the target workqueue
3877 * @attrs: the workqueue_attrs to apply, allocated with alloc_workqueue_attrs()
3878 *
Tejun Heo4c16bd32013-04-01 11:23:36 -07003879 * Apply @attrs to an unbound workqueue @wq. Unless disabled, on NUMA
3880 * machines, this function maps a separate pwq to each NUMA node with
3881 * possibles CPUs in @attrs->cpumask so that work items are affine to the
3882 * NUMA node it was issued on. Older pwqs are released as in-flight work
3883 * items finish. Note that a work item which repeatedly requeues itself
3884 * back-to-back will stay on its current pwq.
Tejun Heo9e8cd2f2013-03-12 11:30:04 -07003885 *
Yacine Belkadid185af32013-07-31 14:59:24 -07003886 * Performs GFP_KERNEL allocations.
3887 *
3888 * Return: 0 on success and -errno on failure.
Tejun Heo9e8cd2f2013-03-12 11:30:04 -07003889 */
3890int apply_workqueue_attrs(struct workqueue_struct *wq,
3891 const struct workqueue_attrs *attrs)
3892{
Tejun Heo4c16bd32013-04-01 11:23:36 -07003893 struct workqueue_attrs *new_attrs, *tmp_attrs;
3894 struct pool_workqueue **pwq_tbl, *dfl_pwq;
Tejun Heof147f292013-04-01 11:23:35 -07003895 int node, ret;
Tejun Heo9e8cd2f2013-03-12 11:30:04 -07003896
Tejun Heo8719dce2013-03-12 11:30:04 -07003897 /* only unbound workqueues can change attributes */
Tejun Heo9e8cd2f2013-03-12 11:30:04 -07003898 if (WARN_ON(!(wq->flags & WQ_UNBOUND)))
3899 return -EINVAL;
3900
Tejun Heo8719dce2013-03-12 11:30:04 -07003901 /* creating multiple pwqs breaks ordering guarantee */
3902 if (WARN_ON((wq->flags & __WQ_ORDERED) && !list_empty(&wq->pwqs)))
3903 return -EINVAL;
3904
Tejun Heo4c16bd32013-04-01 11:23:36 -07003905 pwq_tbl = kzalloc(wq_numa_tbl_len * sizeof(pwq_tbl[0]), GFP_KERNEL);
Tejun Heo13e2e552013-04-01 11:23:31 -07003906 new_attrs = alloc_workqueue_attrs(GFP_KERNEL);
Tejun Heo4c16bd32013-04-01 11:23:36 -07003907 tmp_attrs = alloc_workqueue_attrs(GFP_KERNEL);
3908 if (!pwq_tbl || !new_attrs || !tmp_attrs)
Tejun Heo13e2e552013-04-01 11:23:31 -07003909 goto enomem;
3910
Tejun Heo4c16bd32013-04-01 11:23:36 -07003911 /* make a copy of @attrs and sanitize it */
Tejun Heo13e2e552013-04-01 11:23:31 -07003912 copy_workqueue_attrs(new_attrs, attrs);
3913 cpumask_and(new_attrs->cpumask, new_attrs->cpumask, cpu_possible_mask);
3914
Tejun Heo4c16bd32013-04-01 11:23:36 -07003915 /*
3916 * We may create multiple pwqs with differing cpumasks. Make a
3917 * copy of @new_attrs which will be modified and used to obtain
3918 * pools.
3919 */
3920 copy_workqueue_attrs(tmp_attrs, new_attrs);
Tejun Heo9e8cd2f2013-03-12 11:30:04 -07003921
Tejun Heo4c16bd32013-04-01 11:23:36 -07003922 /*
3923 * CPUs should stay stable across pwq creations and installations.
3924 * Pin CPUs, determine the target cpumask for each node and create
3925 * pwqs accordingly.
3926 */
3927 get_online_cpus();
3928
3929 mutex_lock(&wq_pool_mutex);
3930
3931 /*
3932 * If something goes wrong during CPU up/down, we'll fall back to
3933 * the default pwq covering whole @attrs->cpumask. Always create
3934 * it even if we don't use it immediately.
3935 */
3936 dfl_pwq = alloc_unbound_pwq(wq, new_attrs);
3937 if (!dfl_pwq)
3938 goto enomem_pwq;
3939
3940 for_each_node(node) {
3941 if (wq_calc_node_cpumask(attrs, node, -1, tmp_attrs->cpumask)) {
3942 pwq_tbl[node] = alloc_unbound_pwq(wq, tmp_attrs);
3943 if (!pwq_tbl[node])
3944 goto enomem_pwq;
3945 } else {
3946 dfl_pwq->refcnt++;
3947 pwq_tbl[node] = dfl_pwq;
3948 }
3949 }
3950
3951 mutex_unlock(&wq_pool_mutex);
3952
3953 /* all pwqs have been created successfully, let's install'em */
Tejun Heof147f292013-04-01 11:23:35 -07003954 mutex_lock(&wq->mutex);
3955
Tejun Heof147f292013-04-01 11:23:35 -07003956 copy_workqueue_attrs(wq->unbound_attrs, new_attrs);
Tejun Heo4c16bd32013-04-01 11:23:36 -07003957
3958 /* save the previous pwq and install the new one */
Tejun Heof147f292013-04-01 11:23:35 -07003959 for_each_node(node)
Tejun Heo4c16bd32013-04-01 11:23:36 -07003960 pwq_tbl[node] = numa_pwq_tbl_install(wq, node, pwq_tbl[node]);
3961
3962 /* @dfl_pwq might not have been used, ensure it's linked */
3963 link_pwq(dfl_pwq);
3964 swap(wq->dfl_pwq, dfl_pwq);
Tejun Heof147f292013-04-01 11:23:35 -07003965
3966 mutex_unlock(&wq->mutex);
3967
Tejun Heo4c16bd32013-04-01 11:23:36 -07003968 /* put the old pwqs */
3969 for_each_node(node)
3970 put_pwq_unlocked(pwq_tbl[node]);
3971 put_pwq_unlocked(dfl_pwq);
3972
3973 put_online_cpus();
Tejun Heo48621252013-04-01 11:23:31 -07003974 ret = 0;
3975 /* fall through */
3976out_free:
Tejun Heo4c16bd32013-04-01 11:23:36 -07003977 free_workqueue_attrs(tmp_attrs);
Tejun Heo48621252013-04-01 11:23:31 -07003978 free_workqueue_attrs(new_attrs);
Tejun Heo4c16bd32013-04-01 11:23:36 -07003979 kfree(pwq_tbl);
Tejun Heo48621252013-04-01 11:23:31 -07003980 return ret;
Tejun Heo13e2e552013-04-01 11:23:31 -07003981
Tejun Heo4c16bd32013-04-01 11:23:36 -07003982enomem_pwq:
3983 free_unbound_pwq(dfl_pwq);
3984 for_each_node(node)
3985 if (pwq_tbl && pwq_tbl[node] != dfl_pwq)
3986 free_unbound_pwq(pwq_tbl[node]);
3987 mutex_unlock(&wq_pool_mutex);
3988 put_online_cpus();
Tejun Heo13e2e552013-04-01 11:23:31 -07003989enomem:
Tejun Heo48621252013-04-01 11:23:31 -07003990 ret = -ENOMEM;
3991 goto out_free;
Tejun Heo9e8cd2f2013-03-12 11:30:04 -07003992}
3993
Tejun Heo4c16bd32013-04-01 11:23:36 -07003994/**
3995 * wq_update_unbound_numa - update NUMA affinity of a wq for CPU hot[un]plug
3996 * @wq: the target workqueue
3997 * @cpu: the CPU coming up or going down
3998 * @online: whether @cpu is coming up or going down
3999 *
4000 * This function is to be called from %CPU_DOWN_PREPARE, %CPU_ONLINE and
4001 * %CPU_DOWN_FAILED. @cpu is being hot[un]plugged, update NUMA affinity of
4002 * @wq accordingly.
4003 *
4004 * If NUMA affinity can't be adjusted due to memory allocation failure, it
4005 * falls back to @wq->dfl_pwq which may not be optimal but is always
4006 * correct.
4007 *
4008 * Note that when the last allowed CPU of a NUMA node goes offline for a
4009 * workqueue with a cpumask spanning multiple nodes, the workers which were
4010 * already executing the work items for the workqueue will lose their CPU
4011 * affinity and may execute on any CPU. This is similar to how per-cpu
4012 * workqueues behave on CPU_DOWN. If a workqueue user wants strict
4013 * affinity, it's the user's responsibility to flush the work item from
4014 * CPU_DOWN_PREPARE.
4015 */
4016static void wq_update_unbound_numa(struct workqueue_struct *wq, int cpu,
4017 bool online)
4018{
4019 int node = cpu_to_node(cpu);
4020 int cpu_off = online ? -1 : cpu;
4021 struct pool_workqueue *old_pwq = NULL, *pwq;
4022 struct workqueue_attrs *target_attrs;
4023 cpumask_t *cpumask;
4024
4025 lockdep_assert_held(&wq_pool_mutex);
4026
4027 if (!wq_numa_enabled || !(wq->flags & WQ_UNBOUND))
4028 return;
4029
4030 /*
4031 * We don't wanna alloc/free wq_attrs for each wq for each CPU.
4032 * Let's use a preallocated one. The following buf is protected by
4033 * CPU hotplug exclusion.
4034 */
4035 target_attrs = wq_update_unbound_numa_attrs_buf;
4036 cpumask = target_attrs->cpumask;
4037
4038 mutex_lock(&wq->mutex);
Tejun Heod55262c2013-04-01 11:23:38 -07004039 if (wq->unbound_attrs->no_numa)
4040 goto out_unlock;
Tejun Heo4c16bd32013-04-01 11:23:36 -07004041
4042 copy_workqueue_attrs(target_attrs, wq->unbound_attrs);
4043 pwq = unbound_pwq_by_node(wq, node);
4044
4045 /*
4046 * Let's determine what needs to be done. If the target cpumask is
4047 * different from wq's, we need to compare it to @pwq's and create
4048 * a new one if they don't match. If the target cpumask equals
Daeseok Youn534a3fb2014-04-18 09:08:14 +09004049 * wq's, the default pwq should be used.
Tejun Heo4c16bd32013-04-01 11:23:36 -07004050 */
4051 if (wq_calc_node_cpumask(wq->unbound_attrs, node, cpu_off, cpumask)) {
4052 if (cpumask_equal(cpumask, pwq->pool->attrs->cpumask))
4053 goto out_unlock;
4054 } else {
Daeseok Youn534a3fb2014-04-18 09:08:14 +09004055 goto use_dfl_pwq;
Tejun Heo4c16bd32013-04-01 11:23:36 -07004056 }
4057
4058 mutex_unlock(&wq->mutex);
4059
4060 /* create a new pwq */
4061 pwq = alloc_unbound_pwq(wq, target_attrs);
4062 if (!pwq) {
Fabian Frederick2d916032014-05-12 13:59:35 -04004063 pr_warn("workqueue: allocation failed while updating NUMA affinity of \"%s\"\n",
4064 wq->name);
Daeseok Youn77f300b2014-04-16 14:32:29 +09004065 mutex_lock(&wq->mutex);
4066 goto use_dfl_pwq;
Tejun Heo4c16bd32013-04-01 11:23:36 -07004067 }
4068
4069 /*
4070 * Install the new pwq. As this function is called only from CPU
4071 * hotplug callbacks and applying a new attrs is wrapped with
4072 * get/put_online_cpus(), @wq->unbound_attrs couldn't have changed
4073 * inbetween.
4074 */
4075 mutex_lock(&wq->mutex);
4076 old_pwq = numa_pwq_tbl_install(wq, node, pwq);
4077 goto out_unlock;
4078
4079use_dfl_pwq:
4080 spin_lock_irq(&wq->dfl_pwq->pool->lock);
4081 get_pwq(wq->dfl_pwq);
4082 spin_unlock_irq(&wq->dfl_pwq->pool->lock);
4083 old_pwq = numa_pwq_tbl_install(wq, node, wq->dfl_pwq);
4084out_unlock:
4085 mutex_unlock(&wq->mutex);
4086 put_pwq_unlocked(old_pwq);
4087}
4088
Tejun Heo30cdf242013-03-12 11:29:57 -07004089static int alloc_and_link_pwqs(struct workqueue_struct *wq)
Linus Torvalds1da177e2005-04-16 15:20:36 -07004090{
Tejun Heo49e3cf42013-03-12 11:29:58 -07004091 bool highpri = wq->flags & WQ_HIGHPRI;
Tejun Heo8a2b7532013-09-05 12:30:04 -04004092 int cpu, ret;
Frederic Weisbeckere1d8aa92009-01-12 23:15:46 +01004093
Tejun Heo30cdf242013-03-12 11:29:57 -07004094 if (!(wq->flags & WQ_UNBOUND)) {
Tejun Heo420c0dd2013-03-12 11:29:59 -07004095 wq->cpu_pwqs = alloc_percpu(struct pool_workqueue);
4096 if (!wq->cpu_pwqs)
Tejun Heo30cdf242013-03-12 11:29:57 -07004097 return -ENOMEM;
4098
4099 for_each_possible_cpu(cpu) {
Tejun Heo7fb98ea2013-03-12 11:30:00 -07004100 struct pool_workqueue *pwq =
4101 per_cpu_ptr(wq->cpu_pwqs, cpu);
Tejun Heo7a62c2c2013-03-12 11:30:03 -07004102 struct worker_pool *cpu_pools =
Tejun Heof02ae732013-03-12 11:30:03 -07004103 per_cpu(cpu_worker_pools, cpu);
Tejun Heo30cdf242013-03-12 11:29:57 -07004104
Tejun Heof147f292013-04-01 11:23:35 -07004105 init_pwq(pwq, wq, &cpu_pools[highpri]);
4106
4107 mutex_lock(&wq->mutex);
Tejun Heo1befcf32013-04-01 11:23:35 -07004108 link_pwq(pwq);
Tejun Heof147f292013-04-01 11:23:35 -07004109 mutex_unlock(&wq->mutex);
Tejun Heo30cdf242013-03-12 11:29:57 -07004110 }
Tejun Heo9e8cd2f2013-03-12 11:30:04 -07004111 return 0;
Tejun Heo8a2b7532013-09-05 12:30:04 -04004112 } else if (wq->flags & __WQ_ORDERED) {
4113 ret = apply_workqueue_attrs(wq, ordered_wq_attrs[highpri]);
4114 /* there should only be single pwq for ordering guarantee */
4115 WARN(!ret && (wq->pwqs.next != &wq->dfl_pwq->pwqs_node ||
4116 wq->pwqs.prev != &wq->dfl_pwq->pwqs_node),
4117 "ordering guarantee broken for workqueue %s\n", wq->name);
4118 return ret;
Tejun Heo30cdf242013-03-12 11:29:57 -07004119 } else {
Tejun Heo9e8cd2f2013-03-12 11:30:04 -07004120 return apply_workqueue_attrs(wq, unbound_std_wq_attrs[highpri]);
Tejun Heo30cdf242013-03-12 11:29:57 -07004121 }
Oleg Nesterov3af244332007-05-09 02:34:09 -07004122}
4123
Tejun Heof3421792010-07-02 10:03:51 +02004124static int wq_clamp_max_active(int max_active, unsigned int flags,
4125 const char *name)
Tejun Heob71ab8c2010-06-29 10:07:14 +02004126{
Tejun Heof3421792010-07-02 10:03:51 +02004127 int lim = flags & WQ_UNBOUND ? WQ_UNBOUND_MAX_ACTIVE : WQ_MAX_ACTIVE;
4128
4129 if (max_active < 1 || max_active > lim)
Valentin Ilie044c7822012-08-19 00:52:42 +03004130 pr_warn("workqueue: max_active %d requested for %s is out of range, clamping between %d and %d\n",
4131 max_active, name, 1, lim);
Tejun Heob71ab8c2010-06-29 10:07:14 +02004132
Tejun Heof3421792010-07-02 10:03:51 +02004133 return clamp_val(max_active, 1, lim);
Tejun Heob71ab8c2010-06-29 10:07:14 +02004134}
4135
Tejun Heob196be82012-01-10 15:11:35 -08004136struct workqueue_struct *__alloc_workqueue_key(const char *fmt,
Tejun Heod320c032010-06-29 10:07:14 +02004137 unsigned int flags,
4138 int max_active,
4139 struct lock_class_key *key,
Tejun Heob196be82012-01-10 15:11:35 -08004140 const char *lock_name, ...)
Oleg Nesterov3af244332007-05-09 02:34:09 -07004141{
Tejun Heodf2d5ae2013-04-01 11:23:35 -07004142 size_t tbl_size = 0;
Tejun Heoecf68812013-04-01 11:23:34 -07004143 va_list args;
Oleg Nesterov3af244332007-05-09 02:34:09 -07004144 struct workqueue_struct *wq;
Tejun Heo49e3cf42013-03-12 11:29:58 -07004145 struct pool_workqueue *pwq;
Tejun Heob196be82012-01-10 15:11:35 -08004146
Viresh Kumarcee22a12013-04-08 16:45:40 +05304147 /* see the comment above the definition of WQ_POWER_EFFICIENT */
4148 if ((flags & WQ_POWER_EFFICIENT) && wq_power_efficient)
4149 flags |= WQ_UNBOUND;
4150
Tejun Heoecf68812013-04-01 11:23:34 -07004151 /* allocate wq and format name */
Tejun Heodf2d5ae2013-04-01 11:23:35 -07004152 if (flags & WQ_UNBOUND)
4153 tbl_size = wq_numa_tbl_len * sizeof(wq->numa_pwq_tbl[0]);
4154
4155 wq = kzalloc(sizeof(*wq) + tbl_size, GFP_KERNEL);
Tejun Heob196be82012-01-10 15:11:35 -08004156 if (!wq)
Tejun Heod2c1d402013-03-12 11:30:04 -07004157 return NULL;
Tejun Heob196be82012-01-10 15:11:35 -08004158
Tejun Heo6029a912013-04-01 11:23:34 -07004159 if (flags & WQ_UNBOUND) {
4160 wq->unbound_attrs = alloc_workqueue_attrs(GFP_KERNEL);
4161 if (!wq->unbound_attrs)
4162 goto err_free_wq;
4163 }
4164
Tejun Heoecf68812013-04-01 11:23:34 -07004165 va_start(args, lock_name);
4166 vsnprintf(wq->name, sizeof(wq->name), fmt, args);
Tejun Heob196be82012-01-10 15:11:35 -08004167 va_end(args);
Oleg Nesterov3af244332007-05-09 02:34:09 -07004168
Tejun Heod320c032010-06-29 10:07:14 +02004169 max_active = max_active ?: WQ_DFL_ACTIVE;
Tejun Heob196be82012-01-10 15:11:35 -08004170 max_active = wq_clamp_max_active(max_active, flags, wq->name);
Oleg Nesterov3af244332007-05-09 02:34:09 -07004171
Tejun Heob196be82012-01-10 15:11:35 -08004172 /* init wq */
Tejun Heo97e37d72010-06-29 10:07:10 +02004173 wq->flags = flags;
Tejun Heoa0a1a5f2010-06-29 10:07:12 +02004174 wq->saved_max_active = max_active;
Lai Jiangshan3c25a552013-03-25 16:57:17 -07004175 mutex_init(&wq->mutex);
Tejun Heo112202d2013-02-13 19:29:12 -08004176 atomic_set(&wq->nr_pwqs_to_flush, 0);
Tejun Heo30cdf242013-03-12 11:29:57 -07004177 INIT_LIST_HEAD(&wq->pwqs);
Tejun Heo73f53c42010-06-29 10:07:11 +02004178 INIT_LIST_HEAD(&wq->flusher_queue);
4179 INIT_LIST_HEAD(&wq->flusher_overflow);
Tejun Heo493a1722013-03-12 11:29:59 -07004180 INIT_LIST_HEAD(&wq->maydays);
Oleg Nesterov3af244332007-05-09 02:34:09 -07004181
Johannes Bergeb13ba82008-01-16 09:51:58 +01004182 lockdep_init_map(&wq->lockdep_map, lock_name, key, 0);
Oleg Nesterovcce1a162007-05-09 02:34:13 -07004183 INIT_LIST_HEAD(&wq->list);
Oleg Nesterov3af244332007-05-09 02:34:09 -07004184
Tejun Heo30cdf242013-03-12 11:29:57 -07004185 if (alloc_and_link_pwqs(wq) < 0)
Tejun Heod2c1d402013-03-12 11:30:04 -07004186 goto err_free_wq;
Oleg Nesterov3af244332007-05-09 02:34:09 -07004187
Tejun Heo493008a2013-03-12 11:30:03 -07004188 /*
4189 * Workqueues which may be used during memory reclaim should
4190 * have a rescuer to guarantee forward progress.
4191 */
4192 if (flags & WQ_MEM_RECLAIM) {
Tejun Heoe22bee72010-06-29 10:07:14 +02004193 struct worker *rescuer;
4194
Tejun Heod2c1d402013-03-12 11:30:04 -07004195 rescuer = alloc_worker();
Tejun Heoe22bee72010-06-29 10:07:14 +02004196 if (!rescuer)
Tejun Heod2c1d402013-03-12 11:30:04 -07004197 goto err_destroy;
Tejun Heoe22bee72010-06-29 10:07:14 +02004198
Tejun Heo111c2252013-01-17 17:16:24 -08004199 rescuer->rescue_wq = wq;
4200 rescuer->task = kthread_create(rescuer_thread, rescuer, "%s",
Tejun Heob196be82012-01-10 15:11:35 -08004201 wq->name);
Tejun Heod2c1d402013-03-12 11:30:04 -07004202 if (IS_ERR(rescuer->task)) {
4203 kfree(rescuer);
4204 goto err_destroy;
4205 }
Tejun Heoe22bee72010-06-29 10:07:14 +02004206
Tejun Heod2c1d402013-03-12 11:30:04 -07004207 wq->rescuer = rescuer;
Tejun Heo14a40ff2013-03-19 13:45:20 -07004208 rescuer->task->flags |= PF_NO_SETAFFINITY;
Tejun Heoe22bee72010-06-29 10:07:14 +02004209 wake_up_process(rescuer->task);
Oleg Nesterov3af244332007-05-09 02:34:09 -07004210 }
Oleg Nesterov3af244332007-05-09 02:34:09 -07004211
Tejun Heo226223a2013-03-12 11:30:05 -07004212 if ((wq->flags & WQ_SYSFS) && workqueue_sysfs_register(wq))
4213 goto err_destroy;
4214
Tejun Heoa0a1a5f2010-06-29 10:07:12 +02004215 /*
Lai Jiangshan68e13a62013-03-25 16:57:17 -07004216 * wq_pool_mutex protects global freeze state and workqueues list.
4217 * Grab it, adjust max_active and add the new @wq to workqueues
4218 * list.
Tejun Heoa0a1a5f2010-06-29 10:07:12 +02004219 */
Lai Jiangshan68e13a62013-03-25 16:57:17 -07004220 mutex_lock(&wq_pool_mutex);
Tejun Heoa0a1a5f2010-06-29 10:07:12 +02004221
Lai Jiangshana357fc02013-03-25 16:57:19 -07004222 mutex_lock(&wq->mutex);
Tejun Heo699ce092013-03-13 16:51:35 -07004223 for_each_pwq(pwq, wq)
4224 pwq_adjust_max_active(pwq);
Lai Jiangshana357fc02013-03-25 16:57:19 -07004225 mutex_unlock(&wq->mutex);
Tejun Heoa0a1a5f2010-06-29 10:07:12 +02004226
Tejun Heo15376632010-06-29 10:07:11 +02004227 list_add(&wq->list, &workqueues);
Tejun Heoa0a1a5f2010-06-29 10:07:12 +02004228
Lai Jiangshan68e13a62013-03-25 16:57:17 -07004229 mutex_unlock(&wq_pool_mutex);
Tejun Heo15376632010-06-29 10:07:11 +02004230
Oleg Nesterov3af244332007-05-09 02:34:09 -07004231 return wq;
Tejun Heod2c1d402013-03-12 11:30:04 -07004232
4233err_free_wq:
Tejun Heo6029a912013-04-01 11:23:34 -07004234 free_workqueue_attrs(wq->unbound_attrs);
Tejun Heod2c1d402013-03-12 11:30:04 -07004235 kfree(wq);
4236 return NULL;
4237err_destroy:
4238 destroy_workqueue(wq);
Tejun Heo4690c4a2010-06-29 10:07:10 +02004239 return NULL;
Oleg Nesterov3af244332007-05-09 02:34:09 -07004240}
Tejun Heod320c032010-06-29 10:07:14 +02004241EXPORT_SYMBOL_GPL(__alloc_workqueue_key);
Oleg Nesterov3af244332007-05-09 02:34:09 -07004242
4243/**
4244 * destroy_workqueue - safely terminate a workqueue
4245 * @wq: target workqueue
4246 *
4247 * Safely destroy a workqueue. All work currently pending will be done first.
4248 */
4249void destroy_workqueue(struct workqueue_struct *wq)
4250{
Tejun Heo49e3cf42013-03-12 11:29:58 -07004251 struct pool_workqueue *pwq;
Tejun Heo4c16bd32013-04-01 11:23:36 -07004252 int node;
Oleg Nesterov3af244332007-05-09 02:34:09 -07004253
Tejun Heo9c5a2ba2011-04-05 18:01:44 +02004254 /* drain it before proceeding with destruction */
4255 drain_workqueue(wq);
Tejun Heoc8efcc22010-12-20 19:32:04 +01004256
Tejun Heo6183c002013-03-12 11:29:57 -07004257 /* sanity checks */
Lai Jiangshanb09f4fd2013-03-25 16:57:18 -07004258 mutex_lock(&wq->mutex);
Tejun Heo49e3cf42013-03-12 11:29:58 -07004259 for_each_pwq(pwq, wq) {
Tejun Heo6183c002013-03-12 11:29:57 -07004260 int i;
4261
Tejun Heo76af4d92013-03-12 11:30:00 -07004262 for (i = 0; i < WORK_NR_COLORS; i++) {
4263 if (WARN_ON(pwq->nr_in_flight[i])) {
Lai Jiangshanb09f4fd2013-03-25 16:57:18 -07004264 mutex_unlock(&wq->mutex);
Tejun Heo6183c002013-03-12 11:29:57 -07004265 return;
Tejun Heo76af4d92013-03-12 11:30:00 -07004266 }
4267 }
4268
Lai Jiangshan5c529592013-04-04 10:05:38 +08004269 if (WARN_ON((pwq != wq->dfl_pwq) && (pwq->refcnt > 1)) ||
Tejun Heo8864b4e2013-03-12 11:30:04 -07004270 WARN_ON(pwq->nr_active) ||
Tejun Heo76af4d92013-03-12 11:30:00 -07004271 WARN_ON(!list_empty(&pwq->delayed_works))) {
Lai Jiangshanb09f4fd2013-03-25 16:57:18 -07004272 mutex_unlock(&wq->mutex);
Tejun Heo6183c002013-03-12 11:29:57 -07004273 return;
Tejun Heo76af4d92013-03-12 11:30:00 -07004274 }
Tejun Heo6183c002013-03-12 11:29:57 -07004275 }
Lai Jiangshanb09f4fd2013-03-25 16:57:18 -07004276 mutex_unlock(&wq->mutex);
Tejun Heo6183c002013-03-12 11:29:57 -07004277
Tejun Heoa0a1a5f2010-06-29 10:07:12 +02004278 /*
4279 * wq list is used to freeze wq, remove from list after
4280 * flushing is complete in case freeze races us.
4281 */
Lai Jiangshan68e13a62013-03-25 16:57:17 -07004282 mutex_lock(&wq_pool_mutex);
Tejun Heod2c1d402013-03-12 11:30:04 -07004283 list_del_init(&wq->list);
Lai Jiangshan68e13a62013-03-25 16:57:17 -07004284 mutex_unlock(&wq_pool_mutex);
Oleg Nesterov3af244332007-05-09 02:34:09 -07004285
Tejun Heo226223a2013-03-12 11:30:05 -07004286 workqueue_sysfs_unregister(wq);
4287
Tejun Heo493008a2013-03-12 11:30:03 -07004288 if (wq->rescuer) {
Tejun Heoe22bee72010-06-29 10:07:14 +02004289 kthread_stop(wq->rescuer->task);
Xiaotian Feng8d9df9f2010-08-16 09:54:28 +02004290 kfree(wq->rescuer);
Tejun Heo493008a2013-03-12 11:30:03 -07004291 wq->rescuer = NULL;
Tejun Heoe22bee72010-06-29 10:07:14 +02004292 }
4293
Tejun Heo8864b4e2013-03-12 11:30:04 -07004294 if (!(wq->flags & WQ_UNBOUND)) {
4295 /*
4296 * The base ref is never dropped on per-cpu pwqs. Directly
4297 * free the pwqs and wq.
4298 */
4299 free_percpu(wq->cpu_pwqs);
4300 kfree(wq);
4301 } else {
4302 /*
4303 * We're the sole accessor of @wq at this point. Directly
Tejun Heo4c16bd32013-04-01 11:23:36 -07004304 * access numa_pwq_tbl[] and dfl_pwq to put the base refs.
4305 * @wq will be freed when the last pwq is released.
Tejun Heo8864b4e2013-03-12 11:30:04 -07004306 */
Tejun Heo4c16bd32013-04-01 11:23:36 -07004307 for_each_node(node) {
4308 pwq = rcu_access_pointer(wq->numa_pwq_tbl[node]);
4309 RCU_INIT_POINTER(wq->numa_pwq_tbl[node], NULL);
4310 put_pwq_unlocked(pwq);
4311 }
4312
4313 /*
4314 * Put dfl_pwq. @wq may be freed any time after dfl_pwq is
4315 * put. Don't access it afterwards.
4316 */
4317 pwq = wq->dfl_pwq;
4318 wq->dfl_pwq = NULL;
Tejun Heodce90d42013-04-01 11:23:35 -07004319 put_pwq_unlocked(pwq);
Tejun Heo29c91e92013-03-12 11:30:03 -07004320 }
Oleg Nesterov3af244332007-05-09 02:34:09 -07004321}
4322EXPORT_SYMBOL_GPL(destroy_workqueue);
4323
Tejun Heodcd989c2010-06-29 10:07:14 +02004324/**
4325 * workqueue_set_max_active - adjust max_active of a workqueue
4326 * @wq: target workqueue
4327 * @max_active: new max_active value.
4328 *
4329 * Set max_active of @wq to @max_active.
4330 *
4331 * CONTEXT:
4332 * Don't call from IRQ context.
4333 */
4334void workqueue_set_max_active(struct workqueue_struct *wq, int max_active)
4335{
Tejun Heo49e3cf42013-03-12 11:29:58 -07004336 struct pool_workqueue *pwq;
Tejun Heodcd989c2010-06-29 10:07:14 +02004337
Tejun Heo8719dce2013-03-12 11:30:04 -07004338 /* disallow meddling with max_active for ordered workqueues */
4339 if (WARN_ON(wq->flags & __WQ_ORDERED))
4340 return;
4341
Tejun Heof3421792010-07-02 10:03:51 +02004342 max_active = wq_clamp_max_active(max_active, wq->flags, wq->name);
Tejun Heodcd989c2010-06-29 10:07:14 +02004343
Lai Jiangshana357fc02013-03-25 16:57:19 -07004344 mutex_lock(&wq->mutex);
Tejun Heodcd989c2010-06-29 10:07:14 +02004345
4346 wq->saved_max_active = max_active;
4347
Tejun Heo699ce092013-03-13 16:51:35 -07004348 for_each_pwq(pwq, wq)
4349 pwq_adjust_max_active(pwq);
Tejun Heodcd989c2010-06-29 10:07:14 +02004350
Lai Jiangshana357fc02013-03-25 16:57:19 -07004351 mutex_unlock(&wq->mutex);
Tejun Heodcd989c2010-06-29 10:07:14 +02004352}
4353EXPORT_SYMBOL_GPL(workqueue_set_max_active);
4354
4355/**
Tejun Heoe6267612013-03-12 17:41:37 -07004356 * current_is_workqueue_rescuer - is %current workqueue rescuer?
4357 *
4358 * Determine whether %current is a workqueue rescuer. Can be used from
4359 * work functions to determine whether it's being run off the rescuer task.
Yacine Belkadid185af32013-07-31 14:59:24 -07004360 *
4361 * Return: %true if %current is a workqueue rescuer. %false otherwise.
Tejun Heoe6267612013-03-12 17:41:37 -07004362 */
4363bool current_is_workqueue_rescuer(void)
4364{
4365 struct worker *worker = current_wq_worker();
4366
Lai Jiangshan6a092df2013-03-20 03:28:03 +08004367 return worker && worker->rescue_wq;
Tejun Heoe6267612013-03-12 17:41:37 -07004368}
4369
4370/**
Tejun Heodcd989c2010-06-29 10:07:14 +02004371 * workqueue_congested - test whether a workqueue is congested
4372 * @cpu: CPU in question
4373 * @wq: target workqueue
4374 *
4375 * Test whether @wq's cpu workqueue for @cpu is congested. There is
4376 * no synchronization around this function and the test result is
4377 * unreliable and only useful as advisory hints or for debugging.
4378 *
Tejun Heod3251852013-05-10 11:10:17 -07004379 * If @cpu is WORK_CPU_UNBOUND, the test is performed on the local CPU.
4380 * Note that both per-cpu and unbound workqueues may be associated with
4381 * multiple pool_workqueues which have separate congested states. A
4382 * workqueue being congested on one CPU doesn't mean the workqueue is also
4383 * contested on other CPUs / NUMA nodes.
4384 *
Yacine Belkadid185af32013-07-31 14:59:24 -07004385 * Return:
Tejun Heodcd989c2010-06-29 10:07:14 +02004386 * %true if congested, %false otherwise.
4387 */
Tejun Heod84ff052013-03-12 11:29:59 -07004388bool workqueue_congested(int cpu, struct workqueue_struct *wq)
Tejun Heodcd989c2010-06-29 10:07:14 +02004389{
Tejun Heo7fb98ea2013-03-12 11:30:00 -07004390 struct pool_workqueue *pwq;
Tejun Heo76af4d92013-03-12 11:30:00 -07004391 bool ret;
4392
Lai Jiangshan88109452013-03-20 03:28:10 +08004393 rcu_read_lock_sched();
Tejun Heo7fb98ea2013-03-12 11:30:00 -07004394
Tejun Heod3251852013-05-10 11:10:17 -07004395 if (cpu == WORK_CPU_UNBOUND)
4396 cpu = smp_processor_id();
4397
Tejun Heo7fb98ea2013-03-12 11:30:00 -07004398 if (!(wq->flags & WQ_UNBOUND))
4399 pwq = per_cpu_ptr(wq->cpu_pwqs, cpu);
4400 else
Tejun Heodf2d5ae2013-04-01 11:23:35 -07004401 pwq = unbound_pwq_by_node(wq, cpu_to_node(cpu));
Tejun Heodcd989c2010-06-29 10:07:14 +02004402
Tejun Heo76af4d92013-03-12 11:30:00 -07004403 ret = !list_empty(&pwq->delayed_works);
Lai Jiangshan88109452013-03-20 03:28:10 +08004404 rcu_read_unlock_sched();
Tejun Heo76af4d92013-03-12 11:30:00 -07004405
4406 return ret;
Tejun Heodcd989c2010-06-29 10:07:14 +02004407}
4408EXPORT_SYMBOL_GPL(workqueue_congested);
4409
4410/**
Tejun Heodcd989c2010-06-29 10:07:14 +02004411 * work_busy - test whether a work is currently pending or running
4412 * @work: the work to be tested
4413 *
4414 * Test whether @work is currently pending or running. There is no
4415 * synchronization around this function and the test result is
4416 * unreliable and only useful as advisory hints or for debugging.
Tejun Heodcd989c2010-06-29 10:07:14 +02004417 *
Yacine Belkadid185af32013-07-31 14:59:24 -07004418 * Return:
Tejun Heodcd989c2010-06-29 10:07:14 +02004419 * OR'd bitmask of WORK_BUSY_* bits.
4420 */
4421unsigned int work_busy(struct work_struct *work)
4422{
Tejun Heofa1b54e2013-03-12 11:30:00 -07004423 struct worker_pool *pool;
Tejun Heodcd989c2010-06-29 10:07:14 +02004424 unsigned long flags;
4425 unsigned int ret = 0;
4426
Tejun Heodcd989c2010-06-29 10:07:14 +02004427 if (work_pending(work))
4428 ret |= WORK_BUSY_PENDING;
Tejun Heodcd989c2010-06-29 10:07:14 +02004429
Tejun Heofa1b54e2013-03-12 11:30:00 -07004430 local_irq_save(flags);
4431 pool = get_work_pool(work);
Lai Jiangshan038366c2013-02-06 18:04:53 -08004432 if (pool) {
Tejun Heofa1b54e2013-03-12 11:30:00 -07004433 spin_lock(&pool->lock);
Lai Jiangshan038366c2013-02-06 18:04:53 -08004434 if (find_worker_executing_work(pool, work))
4435 ret |= WORK_BUSY_RUNNING;
Tejun Heofa1b54e2013-03-12 11:30:00 -07004436 spin_unlock(&pool->lock);
Lai Jiangshan038366c2013-02-06 18:04:53 -08004437 }
Tejun Heofa1b54e2013-03-12 11:30:00 -07004438 local_irq_restore(flags);
Tejun Heodcd989c2010-06-29 10:07:14 +02004439
4440 return ret;
4441}
4442EXPORT_SYMBOL_GPL(work_busy);
4443
Tejun Heo3d1cb202013-04-30 15:27:22 -07004444/**
4445 * set_worker_desc - set description for the current work item
4446 * @fmt: printf-style format string
4447 * @...: arguments for the format string
4448 *
4449 * This function can be called by a running work function to describe what
4450 * the work item is about. If the worker task gets dumped, this
4451 * information will be printed out together to help debugging. The
4452 * description can be at most WORKER_DESC_LEN including the trailing '\0'.
4453 */
4454void set_worker_desc(const char *fmt, ...)
4455{
4456 struct worker *worker = current_wq_worker();
4457 va_list args;
4458
4459 if (worker) {
4460 va_start(args, fmt);
4461 vsnprintf(worker->desc, sizeof(worker->desc), fmt, args);
4462 va_end(args);
4463 worker->desc_valid = true;
4464 }
4465}
4466
4467/**
4468 * print_worker_info - print out worker information and description
4469 * @log_lvl: the log level to use when printing
4470 * @task: target task
4471 *
4472 * If @task is a worker and currently executing a work item, print out the
4473 * name of the workqueue being serviced and worker description set with
4474 * set_worker_desc() by the currently executing work item.
4475 *
4476 * This function can be safely called on any task as long as the
4477 * task_struct itself is accessible. While safe, this function isn't
4478 * synchronized and may print out mixups or garbages of limited length.
4479 */
4480void print_worker_info(const char *log_lvl, struct task_struct *task)
4481{
4482 work_func_t *fn = NULL;
4483 char name[WQ_NAME_LEN] = { };
4484 char desc[WORKER_DESC_LEN] = { };
4485 struct pool_workqueue *pwq = NULL;
4486 struct workqueue_struct *wq = NULL;
4487 bool desc_valid = false;
4488 struct worker *worker;
4489
4490 if (!(task->flags & PF_WQ_WORKER))
4491 return;
4492
4493 /*
4494 * This function is called without any synchronization and @task
4495 * could be in any state. Be careful with dereferences.
4496 */
4497 worker = probe_kthread_data(task);
4498
4499 /*
4500 * Carefully copy the associated workqueue's workfn and name. Keep
4501 * the original last '\0' in case the original contains garbage.
4502 */
4503 probe_kernel_read(&fn, &worker->current_func, sizeof(fn));
4504 probe_kernel_read(&pwq, &worker->current_pwq, sizeof(pwq));
4505 probe_kernel_read(&wq, &pwq->wq, sizeof(wq));
4506 probe_kernel_read(name, wq->name, sizeof(name) - 1);
4507
4508 /* copy worker description */
4509 probe_kernel_read(&desc_valid, &worker->desc_valid, sizeof(desc_valid));
4510 if (desc_valid)
4511 probe_kernel_read(desc, worker->desc, sizeof(desc) - 1);
4512
4513 if (fn || name[0] || desc[0]) {
Fabian Frederick2d916032014-05-12 13:59:35 -04004514 pr_info("%sWorkqueue: %s %pf", log_lvl, name, fn);
Tejun Heo3d1cb202013-04-30 15:27:22 -07004515 if (desc[0])
4516 pr_cont(" (%s)", desc);
4517 pr_cont("\n");
4518 }
4519}
4520
Tejun Heodb7bccf2010-06-29 10:07:12 +02004521/*
4522 * CPU hotplug.
4523 *
Tejun Heoe22bee72010-06-29 10:07:14 +02004524 * There are two challenges in supporting CPU hotplug. Firstly, there
Tejun Heo112202d2013-02-13 19:29:12 -08004525 * are a lot of assumptions on strong associations among work, pwq and
Tejun Heo706026c2013-01-24 11:01:34 -08004526 * pool which make migrating pending and scheduled works very
Tejun Heoe22bee72010-06-29 10:07:14 +02004527 * difficult to implement without impacting hot paths. Secondly,
Tejun Heo94cf58b2013-01-24 11:01:33 -08004528 * worker pools serve mix of short, long and very long running works making
Tejun Heoe22bee72010-06-29 10:07:14 +02004529 * blocked draining impractical.
4530 *
Tejun Heo24647572013-01-24 11:01:33 -08004531 * This is solved by allowing the pools to be disassociated from the CPU
Tejun Heo628c78e2012-07-17 12:39:27 -07004532 * running as an unbound one and allowing it to be reattached later if the
4533 * cpu comes back online.
Tejun Heodb7bccf2010-06-29 10:07:12 +02004534 */
4535
Tejun Heo706026c2013-01-24 11:01:34 -08004536static void wq_unbind_fn(struct work_struct *work)
Tejun Heodb7bccf2010-06-29 10:07:12 +02004537{
Tejun Heo38db41d2013-01-24 11:01:34 -08004538 int cpu = smp_processor_id();
Tejun Heo4ce62e92012-07-13 22:16:44 -07004539 struct worker_pool *pool;
Tejun Heodb7bccf2010-06-29 10:07:12 +02004540 struct worker *worker;
Tejun Heodb7bccf2010-06-29 10:07:12 +02004541
Tejun Heof02ae732013-03-12 11:30:03 -07004542 for_each_cpu_worker_pool(pool, cpu) {
Tejun Heo6183c002013-03-12 11:29:57 -07004543 WARN_ON_ONCE(cpu != smp_processor_id());
Tejun Heo94cf58b2013-01-24 11:01:33 -08004544
Tejun Heobc3a1af2013-03-13 19:47:39 -07004545 mutex_lock(&pool->manager_mutex);
Tejun Heo94cf58b2013-01-24 11:01:33 -08004546 spin_lock_irq(&pool->lock);
4547
4548 /*
Tejun Heobc3a1af2013-03-13 19:47:39 -07004549 * We've blocked all manager operations. Make all workers
Tejun Heo94cf58b2013-01-24 11:01:33 -08004550 * unbound and set DISASSOCIATED. Before this, all workers
4551 * except for the ones which are still executing works from
4552 * before the last CPU down must be on the cpu. After
4553 * this, they may become diasporas.
4554 */
Lai Jiangshanda028462014-05-20 17:46:31 +08004555 for_each_pool_worker(worker, pool)
Tejun Heoc9e7cf22013-01-24 11:01:33 -08004556 worker->flags |= WORKER_UNBOUND;
Tejun Heodb7bccf2010-06-29 10:07:12 +02004557
Tejun Heo24647572013-01-24 11:01:33 -08004558 pool->flags |= POOL_DISASSOCIATED;
Tejun Heof2d5a0e2012-07-17 12:39:26 -07004559
Tejun Heo94cf58b2013-01-24 11:01:33 -08004560 spin_unlock_irq(&pool->lock);
Tejun Heobc3a1af2013-03-13 19:47:39 -07004561 mutex_unlock(&pool->manager_mutex);
Tejun Heoe22bee72010-06-29 10:07:14 +02004562
Lai Jiangshaneb283422013-03-08 15:18:28 -08004563 /*
4564 * Call schedule() so that we cross rq->lock and thus can
4565 * guarantee sched callbacks see the %WORKER_UNBOUND flag.
4566 * This is necessary as scheduler callbacks may be invoked
4567 * from other cpus.
4568 */
4569 schedule();
Tejun Heo628c78e2012-07-17 12:39:27 -07004570
Lai Jiangshaneb283422013-03-08 15:18:28 -08004571 /*
4572 * Sched callbacks are disabled now. Zap nr_running.
4573 * After this, nr_running stays zero and need_more_worker()
4574 * and keep_working() are always true as long as the
4575 * worklist is not empty. This pool now behaves as an
4576 * unbound (in terms of concurrency management) pool which
4577 * are served by workers tied to the pool.
4578 */
Tejun Heoe19e3972013-01-24 11:39:44 -08004579 atomic_set(&pool->nr_running, 0);
Lai Jiangshaneb283422013-03-08 15:18:28 -08004580
4581 /*
4582 * With concurrency management just turned off, a busy
4583 * worker blocking could lead to lengthy stalls. Kick off
4584 * unbound chain execution of currently pending work items.
4585 */
4586 spin_lock_irq(&pool->lock);
4587 wake_up_worker(pool);
4588 spin_unlock_irq(&pool->lock);
4589 }
Tejun Heodb7bccf2010-06-29 10:07:12 +02004590}
4591
Tejun Heobd7c0892013-03-19 13:45:21 -07004592/**
4593 * rebind_workers - rebind all workers of a pool to the associated CPU
4594 * @pool: pool of interest
4595 *
Tejun Heoa9ab7752013-03-19 13:45:21 -07004596 * @pool->cpu is coming online. Rebind all workers to the CPU.
Tejun Heobd7c0892013-03-19 13:45:21 -07004597 */
4598static void rebind_workers(struct worker_pool *pool)
4599{
Tejun Heoa9ab7752013-03-19 13:45:21 -07004600 struct worker *worker;
Tejun Heobd7c0892013-03-19 13:45:21 -07004601
4602 lockdep_assert_held(&pool->manager_mutex);
Tejun Heobd7c0892013-03-19 13:45:21 -07004603
Tejun Heoa9ab7752013-03-19 13:45:21 -07004604 /*
4605 * Restore CPU affinity of all workers. As all idle workers should
4606 * be on the run-queue of the associated CPU before any local
4607 * wake-ups for concurrency management happen, restore CPU affinty
4608 * of all workers first and then clear UNBOUND. As we're called
4609 * from CPU_ONLINE, the following shouldn't fail.
4610 */
Lai Jiangshanda028462014-05-20 17:46:31 +08004611 for_each_pool_worker(worker, pool)
Tejun Heoa9ab7752013-03-19 13:45:21 -07004612 WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task,
4613 pool->attrs->cpumask) < 0);
4614
4615 spin_lock_irq(&pool->lock);
4616
Lai Jiangshanda028462014-05-20 17:46:31 +08004617 for_each_pool_worker(worker, pool) {
Tejun Heoa9ab7752013-03-19 13:45:21 -07004618 unsigned int worker_flags = worker->flags;
Tejun Heobd7c0892013-03-19 13:45:21 -07004619
4620 /*
Tejun Heoa9ab7752013-03-19 13:45:21 -07004621 * A bound idle worker should actually be on the runqueue
4622 * of the associated CPU for local wake-ups targeting it to
4623 * work. Kick all idle workers so that they migrate to the
4624 * associated CPU. Doing this in the same loop as
4625 * replacing UNBOUND with REBOUND is safe as no worker will
4626 * be bound before @pool->lock is released.
Tejun Heobd7c0892013-03-19 13:45:21 -07004627 */
Tejun Heoa9ab7752013-03-19 13:45:21 -07004628 if (worker_flags & WORKER_IDLE)
4629 wake_up_process(worker->task);
4630
4631 /*
4632 * We want to clear UNBOUND but can't directly call
4633 * worker_clr_flags() or adjust nr_running. Atomically
4634 * replace UNBOUND with another NOT_RUNNING flag REBOUND.
4635 * @worker will clear REBOUND using worker_clr_flags() when
4636 * it initiates the next execution cycle thus restoring
4637 * concurrency management. Note that when or whether
4638 * @worker clears REBOUND doesn't affect correctness.
4639 *
4640 * ACCESS_ONCE() is necessary because @worker->flags may be
4641 * tested without holding any lock in
4642 * wq_worker_waking_up(). Without it, NOT_RUNNING test may
4643 * fail incorrectly leading to premature concurrency
4644 * management operations.
4645 */
4646 WARN_ON_ONCE(!(worker_flags & WORKER_UNBOUND));
4647 worker_flags |= WORKER_REBOUND;
4648 worker_flags &= ~WORKER_UNBOUND;
4649 ACCESS_ONCE(worker->flags) = worker_flags;
Tejun Heobd7c0892013-03-19 13:45:21 -07004650 }
4651
Tejun Heoa9ab7752013-03-19 13:45:21 -07004652 spin_unlock_irq(&pool->lock);
Tejun Heobd7c0892013-03-19 13:45:21 -07004653}
4654
Tejun Heo7dbc7252013-03-19 13:45:21 -07004655/**
4656 * restore_unbound_workers_cpumask - restore cpumask of unbound workers
4657 * @pool: unbound pool of interest
4658 * @cpu: the CPU which is coming up
4659 *
4660 * An unbound pool may end up with a cpumask which doesn't have any online
4661 * CPUs. When a worker of such pool get scheduled, the scheduler resets
4662 * its cpus_allowed. If @cpu is in @pool's cpumask which didn't have any
4663 * online CPU before, cpus_allowed of all its workers should be restored.
4664 */
4665static void restore_unbound_workers_cpumask(struct worker_pool *pool, int cpu)
4666{
4667 static cpumask_t cpumask;
4668 struct worker *worker;
Tejun Heo7dbc7252013-03-19 13:45:21 -07004669
4670 lockdep_assert_held(&pool->manager_mutex);
4671
4672 /* is @cpu allowed for @pool? */
4673 if (!cpumask_test_cpu(cpu, pool->attrs->cpumask))
4674 return;
4675
4676 /* is @cpu the only online CPU? */
4677 cpumask_and(&cpumask, pool->attrs->cpumask, cpu_online_mask);
4678 if (cpumask_weight(&cpumask) != 1)
4679 return;
4680
4681 /* as we're called from CPU_ONLINE, the following shouldn't fail */
Lai Jiangshanda028462014-05-20 17:46:31 +08004682 for_each_pool_worker(worker, pool)
Tejun Heo7dbc7252013-03-19 13:45:21 -07004683 WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task,
4684 pool->attrs->cpumask) < 0);
4685}
4686
Tejun Heo8db25e72012-07-17 12:39:28 -07004687/*
4688 * Workqueues should be brought up before normal priority CPU notifiers.
4689 * This will be registered high priority CPU notifier.
4690 */
Paul Gortmaker0db06282013-06-19 14:53:51 -04004691static int workqueue_cpu_up_callback(struct notifier_block *nfb,
Tejun Heo8db25e72012-07-17 12:39:28 -07004692 unsigned long action,
4693 void *hcpu)
Oleg Nesterov3af244332007-05-09 02:34:09 -07004694{
Tejun Heod84ff052013-03-12 11:29:59 -07004695 int cpu = (unsigned long)hcpu;
Tejun Heo4ce62e92012-07-13 22:16:44 -07004696 struct worker_pool *pool;
Tejun Heo4c16bd32013-04-01 11:23:36 -07004697 struct workqueue_struct *wq;
Tejun Heo7dbc7252013-03-19 13:45:21 -07004698 int pi;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004699
Tejun Heo8db25e72012-07-17 12:39:28 -07004700 switch (action & ~CPU_TASKS_FROZEN) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07004701 case CPU_UP_PREPARE:
Tejun Heof02ae732013-03-12 11:30:03 -07004702 for_each_cpu_worker_pool(pool, cpu) {
Tejun Heo3ce63372012-07-17 12:39:27 -07004703 if (pool->nr_workers)
4704 continue;
Tejun Heoebf44d12013-03-13 19:47:39 -07004705 if (create_and_start_worker(pool) < 0)
Tejun Heo3ce63372012-07-17 12:39:27 -07004706 return NOTIFY_BAD;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004707 }
Tejun Heodb7bccf2010-06-29 10:07:12 +02004708 break;
Oleg Nesterov00dfcaf2008-04-29 01:00:27 -07004709
Tejun Heo65758202012-07-17 12:39:26 -07004710 case CPU_DOWN_FAILED:
4711 case CPU_ONLINE:
Lai Jiangshan68e13a62013-03-25 16:57:17 -07004712 mutex_lock(&wq_pool_mutex);
Tejun Heo7dbc7252013-03-19 13:45:21 -07004713
4714 for_each_pool(pool, pi) {
Tejun Heobc3a1af2013-03-13 19:47:39 -07004715 mutex_lock(&pool->manager_mutex);
Tejun Heo94cf58b2013-01-24 11:01:33 -08004716
Tejun Heo7dbc7252013-03-19 13:45:21 -07004717 if (pool->cpu == cpu) {
4718 spin_lock_irq(&pool->lock);
4719 pool->flags &= ~POOL_DISASSOCIATED;
4720 spin_unlock_irq(&pool->lock);
Tejun Heoa9ab7752013-03-19 13:45:21 -07004721
Tejun Heo7dbc7252013-03-19 13:45:21 -07004722 rebind_workers(pool);
4723 } else if (pool->cpu < 0) {
4724 restore_unbound_workers_cpumask(pool, cpu);
4725 }
Tejun Heo94cf58b2013-01-24 11:01:33 -08004726
Tejun Heobc3a1af2013-03-13 19:47:39 -07004727 mutex_unlock(&pool->manager_mutex);
Tejun Heo94cf58b2013-01-24 11:01:33 -08004728 }
Tejun Heo7dbc7252013-03-19 13:45:21 -07004729
Tejun Heo4c16bd32013-04-01 11:23:36 -07004730 /* update NUMA affinity of unbound workqueues */
4731 list_for_each_entry(wq, &workqueues, list)
4732 wq_update_unbound_numa(wq, cpu, true);
4733
Lai Jiangshan68e13a62013-03-25 16:57:17 -07004734 mutex_unlock(&wq_pool_mutex);
Tejun Heo8db25e72012-07-17 12:39:28 -07004735 break;
Tejun Heo65758202012-07-17 12:39:26 -07004736 }
4737 return NOTIFY_OK;
4738}
4739
4740/*
4741 * Workqueues should be brought down after normal priority CPU notifiers.
4742 * This will be registered as low priority CPU notifier.
4743 */
Paul Gortmaker0db06282013-06-19 14:53:51 -04004744static int workqueue_cpu_down_callback(struct notifier_block *nfb,
Tejun Heo65758202012-07-17 12:39:26 -07004745 unsigned long action,
4746 void *hcpu)
4747{
Tejun Heod84ff052013-03-12 11:29:59 -07004748 int cpu = (unsigned long)hcpu;
Tejun Heo8db25e72012-07-17 12:39:28 -07004749 struct work_struct unbind_work;
Tejun Heo4c16bd32013-04-01 11:23:36 -07004750 struct workqueue_struct *wq;
Tejun Heo8db25e72012-07-17 12:39:28 -07004751
Tejun Heo65758202012-07-17 12:39:26 -07004752 switch (action & ~CPU_TASKS_FROZEN) {
4753 case CPU_DOWN_PREPARE:
Tejun Heo4c16bd32013-04-01 11:23:36 -07004754 /* unbinding per-cpu workers should happen on the local CPU */
Tejun Heo706026c2013-01-24 11:01:34 -08004755 INIT_WORK_ONSTACK(&unbind_work, wq_unbind_fn);
Joonsoo Kim7635d2f2012-08-15 23:25:41 +09004756 queue_work_on(cpu, system_highpri_wq, &unbind_work);
Tejun Heo4c16bd32013-04-01 11:23:36 -07004757
4758 /* update NUMA affinity of unbound workqueues */
4759 mutex_lock(&wq_pool_mutex);
4760 list_for_each_entry(wq, &workqueues, list)
4761 wq_update_unbound_numa(wq, cpu, false);
4762 mutex_unlock(&wq_pool_mutex);
4763
4764 /* wait for per-cpu unbinding to finish */
Tejun Heo8db25e72012-07-17 12:39:28 -07004765 flush_work(&unbind_work);
Chuansheng Liu440a1132014-01-11 22:26:33 -05004766 destroy_work_on_stack(&unbind_work);
Tejun Heo8db25e72012-07-17 12:39:28 -07004767 break;
Tejun Heo65758202012-07-17 12:39:26 -07004768 }
4769 return NOTIFY_OK;
4770}
4771
Rusty Russell2d3854a2008-11-05 13:39:10 +11004772#ifdef CONFIG_SMP
Rusty Russell8ccad402009-01-16 15:31:15 -08004773
Rusty Russell2d3854a2008-11-05 13:39:10 +11004774struct work_for_cpu {
Tejun Heoed48ece2012-09-18 12:48:43 -07004775 struct work_struct work;
Rusty Russell2d3854a2008-11-05 13:39:10 +11004776 long (*fn)(void *);
4777 void *arg;
4778 long ret;
4779};
4780
Tejun Heoed48ece2012-09-18 12:48:43 -07004781static void work_for_cpu_fn(struct work_struct *work)
Rusty Russell2d3854a2008-11-05 13:39:10 +11004782{
Tejun Heoed48ece2012-09-18 12:48:43 -07004783 struct work_for_cpu *wfc = container_of(work, struct work_for_cpu, work);
4784
Rusty Russell2d3854a2008-11-05 13:39:10 +11004785 wfc->ret = wfc->fn(wfc->arg);
4786}
4787
4788/**
4789 * work_on_cpu - run a function in user context on a particular cpu
4790 * @cpu: the cpu to run on
4791 * @fn: the function to run
4792 * @arg: the function arg
4793 *
Rusty Russell31ad9082009-01-16 15:31:15 -08004794 * It is up to the caller to ensure that the cpu doesn't go offline.
Andrew Morton6b440032009-04-09 09:50:37 -06004795 * The caller must not hold any locks which would prevent @fn from completing.
Yacine Belkadid185af32013-07-31 14:59:24 -07004796 *
4797 * Return: The value @fn returns.
Rusty Russell2d3854a2008-11-05 13:39:10 +11004798 */
Tejun Heod84ff052013-03-12 11:29:59 -07004799long work_on_cpu(int cpu, long (*fn)(void *), void *arg)
Rusty Russell2d3854a2008-11-05 13:39:10 +11004800{
Tejun Heoed48ece2012-09-18 12:48:43 -07004801 struct work_for_cpu wfc = { .fn = fn, .arg = arg };
Rusty Russell2d3854a2008-11-05 13:39:10 +11004802
Tejun Heoed48ece2012-09-18 12:48:43 -07004803 INIT_WORK_ONSTACK(&wfc.work, work_for_cpu_fn);
4804 schedule_work_on(cpu, &wfc.work);
Bjorn Helgaas12997d12013-11-18 11:00:29 -07004805 flush_work(&wfc.work);
Chuansheng Liu440a1132014-01-11 22:26:33 -05004806 destroy_work_on_stack(&wfc.work);
Rusty Russell2d3854a2008-11-05 13:39:10 +11004807 return wfc.ret;
4808}
4809EXPORT_SYMBOL_GPL(work_on_cpu);
4810#endif /* CONFIG_SMP */
4811
Tejun Heoa0a1a5f2010-06-29 10:07:12 +02004812#ifdef CONFIG_FREEZER
Rusty Russelle7577c52009-01-01 10:12:25 +10304813
Tejun Heoa0a1a5f2010-06-29 10:07:12 +02004814/**
4815 * freeze_workqueues_begin - begin freezing workqueues
4816 *
Tejun Heo58a69cb2011-02-16 09:25:31 +01004817 * Start freezing workqueues. After this function returns, all freezable
Tejun Heoc5aa87b2013-03-13 16:51:36 -07004818 * workqueues will queue new works to their delayed_works list instead of
Tejun Heo706026c2013-01-24 11:01:34 -08004819 * pool->worklist.
Tejun Heoa0a1a5f2010-06-29 10:07:12 +02004820 *
4821 * CONTEXT:
Lai Jiangshana357fc02013-03-25 16:57:19 -07004822 * Grabs and releases wq_pool_mutex, wq->mutex and pool->lock's.
Tejun Heoa0a1a5f2010-06-29 10:07:12 +02004823 */
4824void freeze_workqueues_begin(void)
4825{
Tejun Heo17116962013-03-12 11:29:58 -07004826 struct worker_pool *pool;
Tejun Heo24b8a842013-03-12 11:29:58 -07004827 struct workqueue_struct *wq;
4828 struct pool_workqueue *pwq;
Tejun Heo611c92a2013-03-13 16:51:36 -07004829 int pi;
Tejun Heoa0a1a5f2010-06-29 10:07:12 +02004830
Lai Jiangshan68e13a62013-03-25 16:57:17 -07004831 mutex_lock(&wq_pool_mutex);
Tejun Heoa0a1a5f2010-06-29 10:07:12 +02004832
Tejun Heo6183c002013-03-12 11:29:57 -07004833 WARN_ON_ONCE(workqueue_freezing);
Tejun Heoa0a1a5f2010-06-29 10:07:12 +02004834 workqueue_freezing = true;
4835
Tejun Heo24b8a842013-03-12 11:29:58 -07004836 /* set FREEZING */
Tejun Heo611c92a2013-03-13 16:51:36 -07004837 for_each_pool(pool, pi) {
Tejun Heo5bcab332013-03-13 19:47:40 -07004838 spin_lock_irq(&pool->lock);
Tejun Heo17116962013-03-12 11:29:58 -07004839 WARN_ON_ONCE(pool->flags & POOL_FREEZING);
4840 pool->flags |= POOL_FREEZING;
Tejun Heo5bcab332013-03-13 19:47:40 -07004841 spin_unlock_irq(&pool->lock);
Tejun Heoa0a1a5f2010-06-29 10:07:12 +02004842 }
4843
Tejun Heo24b8a842013-03-12 11:29:58 -07004844 list_for_each_entry(wq, &workqueues, list) {
Lai Jiangshana357fc02013-03-25 16:57:19 -07004845 mutex_lock(&wq->mutex);
Tejun Heo699ce092013-03-13 16:51:35 -07004846 for_each_pwq(pwq, wq)
4847 pwq_adjust_max_active(pwq);
Lai Jiangshana357fc02013-03-25 16:57:19 -07004848 mutex_unlock(&wq->mutex);
Tejun Heo24b8a842013-03-12 11:29:58 -07004849 }
Tejun Heo5bcab332013-03-13 19:47:40 -07004850
Lai Jiangshan68e13a62013-03-25 16:57:17 -07004851 mutex_unlock(&wq_pool_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004852}
Tejun Heoa0a1a5f2010-06-29 10:07:12 +02004853
4854/**
Tejun Heo58a69cb2011-02-16 09:25:31 +01004855 * freeze_workqueues_busy - are freezable workqueues still busy?
Tejun Heoa0a1a5f2010-06-29 10:07:12 +02004856 *
4857 * Check whether freezing is complete. This function must be called
4858 * between freeze_workqueues_begin() and thaw_workqueues().
4859 *
4860 * CONTEXT:
Lai Jiangshan68e13a62013-03-25 16:57:17 -07004861 * Grabs and releases wq_pool_mutex.
Tejun Heoa0a1a5f2010-06-29 10:07:12 +02004862 *
Yacine Belkadid185af32013-07-31 14:59:24 -07004863 * Return:
Tejun Heo58a69cb2011-02-16 09:25:31 +01004864 * %true if some freezable workqueues are still busy. %false if freezing
4865 * is complete.
Tejun Heoa0a1a5f2010-06-29 10:07:12 +02004866 */
4867bool freeze_workqueues_busy(void)
4868{
Tejun Heoa0a1a5f2010-06-29 10:07:12 +02004869 bool busy = false;
Tejun Heo24b8a842013-03-12 11:29:58 -07004870 struct workqueue_struct *wq;
4871 struct pool_workqueue *pwq;
Tejun Heoa0a1a5f2010-06-29 10:07:12 +02004872
Lai Jiangshan68e13a62013-03-25 16:57:17 -07004873 mutex_lock(&wq_pool_mutex);
Tejun Heoa0a1a5f2010-06-29 10:07:12 +02004874
Tejun Heo6183c002013-03-12 11:29:57 -07004875 WARN_ON_ONCE(!workqueue_freezing);
Tejun Heoa0a1a5f2010-06-29 10:07:12 +02004876
Tejun Heo24b8a842013-03-12 11:29:58 -07004877 list_for_each_entry(wq, &workqueues, list) {
4878 if (!(wq->flags & WQ_FREEZABLE))
4879 continue;
Tejun Heoa0a1a5f2010-06-29 10:07:12 +02004880 /*
4881 * nr_active is monotonically decreasing. It's safe
4882 * to peek without lock.
4883 */
Lai Jiangshan88109452013-03-20 03:28:10 +08004884 rcu_read_lock_sched();
Tejun Heo24b8a842013-03-12 11:29:58 -07004885 for_each_pwq(pwq, wq) {
Tejun Heo6183c002013-03-12 11:29:57 -07004886 WARN_ON_ONCE(pwq->nr_active < 0);
Tejun Heo112202d2013-02-13 19:29:12 -08004887 if (pwq->nr_active) {
Tejun Heoa0a1a5f2010-06-29 10:07:12 +02004888 busy = true;
Lai Jiangshan88109452013-03-20 03:28:10 +08004889 rcu_read_unlock_sched();
Tejun Heoa0a1a5f2010-06-29 10:07:12 +02004890 goto out_unlock;
4891 }
4892 }
Lai Jiangshan88109452013-03-20 03:28:10 +08004893 rcu_read_unlock_sched();
Tejun Heoa0a1a5f2010-06-29 10:07:12 +02004894 }
4895out_unlock:
Lai Jiangshan68e13a62013-03-25 16:57:17 -07004896 mutex_unlock(&wq_pool_mutex);
Tejun Heoa0a1a5f2010-06-29 10:07:12 +02004897 return busy;
4898}
4899
4900/**
4901 * thaw_workqueues - thaw workqueues
4902 *
4903 * Thaw workqueues. Normal queueing is restored and all collected
Tejun Heo706026c2013-01-24 11:01:34 -08004904 * frozen works are transferred to their respective pool worklists.
Tejun Heoa0a1a5f2010-06-29 10:07:12 +02004905 *
4906 * CONTEXT:
Lai Jiangshana357fc02013-03-25 16:57:19 -07004907 * Grabs and releases wq_pool_mutex, wq->mutex and pool->lock's.
Tejun Heoa0a1a5f2010-06-29 10:07:12 +02004908 */
4909void thaw_workqueues(void)
4910{
Tejun Heo24b8a842013-03-12 11:29:58 -07004911 struct workqueue_struct *wq;
4912 struct pool_workqueue *pwq;
4913 struct worker_pool *pool;
Tejun Heo611c92a2013-03-13 16:51:36 -07004914 int pi;
Tejun Heoa0a1a5f2010-06-29 10:07:12 +02004915
Lai Jiangshan68e13a62013-03-25 16:57:17 -07004916 mutex_lock(&wq_pool_mutex);
Tejun Heoa0a1a5f2010-06-29 10:07:12 +02004917
4918 if (!workqueue_freezing)
4919 goto out_unlock;
4920
Tejun Heo24b8a842013-03-12 11:29:58 -07004921 /* clear FREEZING */
Tejun Heo611c92a2013-03-13 16:51:36 -07004922 for_each_pool(pool, pi) {
Tejun Heo5bcab332013-03-13 19:47:40 -07004923 spin_lock_irq(&pool->lock);
Tejun Heo24b8a842013-03-12 11:29:58 -07004924 WARN_ON_ONCE(!(pool->flags & POOL_FREEZING));
4925 pool->flags &= ~POOL_FREEZING;
Tejun Heo5bcab332013-03-13 19:47:40 -07004926 spin_unlock_irq(&pool->lock);
Tejun Heo24b8a842013-03-12 11:29:58 -07004927 }
Tejun Heo8b03ae32010-06-29 10:07:12 +02004928
Tejun Heo24b8a842013-03-12 11:29:58 -07004929 /* restore max_active and repopulate worklist */
4930 list_for_each_entry(wq, &workqueues, list) {
Lai Jiangshana357fc02013-03-25 16:57:19 -07004931 mutex_lock(&wq->mutex);
Tejun Heo699ce092013-03-13 16:51:35 -07004932 for_each_pwq(pwq, wq)
4933 pwq_adjust_max_active(pwq);
Lai Jiangshana357fc02013-03-25 16:57:19 -07004934 mutex_unlock(&wq->mutex);
Tejun Heoa0a1a5f2010-06-29 10:07:12 +02004935 }
4936
4937 workqueue_freezing = false;
4938out_unlock:
Lai Jiangshan68e13a62013-03-25 16:57:17 -07004939 mutex_unlock(&wq_pool_mutex);
Tejun Heoa0a1a5f2010-06-29 10:07:12 +02004940}
4941#endif /* CONFIG_FREEZER */
4942
Tejun Heobce90382013-04-01 11:23:32 -07004943static void __init wq_numa_init(void)
4944{
4945 cpumask_var_t *tbl;
4946 int node, cpu;
4947
4948 /* determine NUMA pwq table len - highest node id + 1 */
4949 for_each_node(node)
4950 wq_numa_tbl_len = max(wq_numa_tbl_len, node + 1);
4951
4952 if (num_possible_nodes() <= 1)
4953 return;
4954
Tejun Heod55262c2013-04-01 11:23:38 -07004955 if (wq_disable_numa) {
4956 pr_info("workqueue: NUMA affinity support disabled\n");
4957 return;
4958 }
4959
Tejun Heo4c16bd32013-04-01 11:23:36 -07004960 wq_update_unbound_numa_attrs_buf = alloc_workqueue_attrs(GFP_KERNEL);
4961 BUG_ON(!wq_update_unbound_numa_attrs_buf);
4962
Tejun Heobce90382013-04-01 11:23:32 -07004963 /*
4964 * We want masks of possible CPUs of each node which isn't readily
4965 * available. Build one from cpu_to_node() which should have been
4966 * fully initialized by now.
4967 */
4968 tbl = kzalloc(wq_numa_tbl_len * sizeof(tbl[0]), GFP_KERNEL);
4969 BUG_ON(!tbl);
4970
4971 for_each_node(node)
Tejun Heo1be0c252013-05-15 14:24:24 -07004972 BUG_ON(!alloc_cpumask_var_node(&tbl[node], GFP_KERNEL,
4973 node_online(node) ? node : NUMA_NO_NODE));
Tejun Heobce90382013-04-01 11:23:32 -07004974
4975 for_each_possible_cpu(cpu) {
4976 node = cpu_to_node(cpu);
4977 if (WARN_ON(node == NUMA_NO_NODE)) {
4978 pr_warn("workqueue: NUMA node mapping not available for cpu%d, disabling NUMA support\n", cpu);
4979 /* happens iff arch is bonkers, let's just proceed */
4980 return;
4981 }
4982 cpumask_set_cpu(cpu, tbl[node]);
4983 }
4984
4985 wq_numa_possible_cpumask = tbl;
4986 wq_numa_enabled = true;
4987}
4988
Suresh Siddha6ee05782010-07-30 14:57:37 -07004989static int __init init_workqueues(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -07004990{
Tejun Heo7a4e3442013-03-12 11:30:00 -07004991 int std_nice[NR_STD_WORKER_POOLS] = { 0, HIGHPRI_NICE_LEVEL };
4992 int i, cpu;
Tejun Heoc34056a2010-06-29 10:07:11 +02004993
Tejun Heoe904e6c2013-03-12 11:29:57 -07004994 WARN_ON(__alignof__(struct pool_workqueue) < __alignof__(long long));
4995
4996 pwq_cache = KMEM_CACHE(pool_workqueue, SLAB_PANIC);
4997
Tejun Heo65758202012-07-17 12:39:26 -07004998 cpu_notifier(workqueue_cpu_up_callback, CPU_PRI_WORKQUEUE_UP);
Lai Jiangshana5b4e572012-09-18 09:59:23 -07004999 hotcpu_notifier(workqueue_cpu_down_callback, CPU_PRI_WORKQUEUE_DOWN);
Tejun Heo8b03ae32010-06-29 10:07:12 +02005000
Tejun Heobce90382013-04-01 11:23:32 -07005001 wq_numa_init();
5002
Tejun Heo706026c2013-01-24 11:01:34 -08005003 /* initialize CPU pools */
Tejun Heo29c91e92013-03-12 11:30:03 -07005004 for_each_possible_cpu(cpu) {
Tejun Heo4ce62e92012-07-13 22:16:44 -07005005 struct worker_pool *pool;
Tejun Heo8b03ae32010-06-29 10:07:12 +02005006
Tejun Heo7a4e3442013-03-12 11:30:00 -07005007 i = 0;
Tejun Heof02ae732013-03-12 11:30:03 -07005008 for_each_cpu_worker_pool(pool, cpu) {
Tejun Heo7a4e3442013-03-12 11:30:00 -07005009 BUG_ON(init_worker_pool(pool));
Tejun Heoec22ca52013-01-24 11:01:33 -08005010 pool->cpu = cpu;
Tejun Heo29c91e92013-03-12 11:30:03 -07005011 cpumask_copy(pool->attrs->cpumask, cpumask_of(cpu));
Tejun Heo7a4e3442013-03-12 11:30:00 -07005012 pool->attrs->nice = std_nice[i++];
Tejun Heof3f90ad2013-04-01 11:23:34 -07005013 pool->node = cpu_to_node(cpu);
Tejun Heo7a4e3442013-03-12 11:30:00 -07005014
Tejun Heo9daf9e62013-01-24 11:01:33 -08005015 /* alloc pool ID */
Lai Jiangshan68e13a62013-03-25 16:57:17 -07005016 mutex_lock(&wq_pool_mutex);
Tejun Heo9daf9e62013-01-24 11:01:33 -08005017 BUG_ON(worker_pool_assign_id(pool));
Lai Jiangshan68e13a62013-03-25 16:57:17 -07005018 mutex_unlock(&wq_pool_mutex);
Tejun Heo4ce62e92012-07-13 22:16:44 -07005019 }
Tejun Heo8b03ae32010-06-29 10:07:12 +02005020 }
5021
Tejun Heoe22bee72010-06-29 10:07:14 +02005022 /* create the initial worker */
Tejun Heo29c91e92013-03-12 11:30:03 -07005023 for_each_online_cpu(cpu) {
Tejun Heo4ce62e92012-07-13 22:16:44 -07005024 struct worker_pool *pool;
Tejun Heoe22bee72010-06-29 10:07:14 +02005025
Tejun Heof02ae732013-03-12 11:30:03 -07005026 for_each_cpu_worker_pool(pool, cpu) {
Tejun Heo29c91e92013-03-12 11:30:03 -07005027 pool->flags &= ~POOL_DISASSOCIATED;
Tejun Heoebf44d12013-03-13 19:47:39 -07005028 BUG_ON(create_and_start_worker(pool) < 0);
Tejun Heo4ce62e92012-07-13 22:16:44 -07005029 }
Tejun Heoe22bee72010-06-29 10:07:14 +02005030 }
5031
Tejun Heo8a2b7532013-09-05 12:30:04 -04005032 /* create default unbound and ordered wq attrs */
Tejun Heo29c91e92013-03-12 11:30:03 -07005033 for (i = 0; i < NR_STD_WORKER_POOLS; i++) {
5034 struct workqueue_attrs *attrs;
5035
5036 BUG_ON(!(attrs = alloc_workqueue_attrs(GFP_KERNEL)));
Tejun Heo29c91e92013-03-12 11:30:03 -07005037 attrs->nice = std_nice[i];
Tejun Heo29c91e92013-03-12 11:30:03 -07005038 unbound_std_wq_attrs[i] = attrs;
Tejun Heo8a2b7532013-09-05 12:30:04 -04005039
5040 /*
5041 * An ordered wq should have only one pwq as ordering is
5042 * guaranteed by max_active which is enforced by pwqs.
5043 * Turn off NUMA so that dfl_pwq is used for all nodes.
5044 */
5045 BUG_ON(!(attrs = alloc_workqueue_attrs(GFP_KERNEL)));
5046 attrs->nice = std_nice[i];
5047 attrs->no_numa = true;
5048 ordered_wq_attrs[i] = attrs;
Tejun Heo29c91e92013-03-12 11:30:03 -07005049 }
5050
Tejun Heod320c032010-06-29 10:07:14 +02005051 system_wq = alloc_workqueue("events", 0, 0);
Joonsoo Kim1aabe902012-08-15 23:25:39 +09005052 system_highpri_wq = alloc_workqueue("events_highpri", WQ_HIGHPRI, 0);
Tejun Heod320c032010-06-29 10:07:14 +02005053 system_long_wq = alloc_workqueue("events_long", 0, 0);
Tejun Heof3421792010-07-02 10:03:51 +02005054 system_unbound_wq = alloc_workqueue("events_unbound", WQ_UNBOUND,
5055 WQ_UNBOUND_MAX_ACTIVE);
Tejun Heo24d51ad2011-02-21 09:52:50 +01005056 system_freezable_wq = alloc_workqueue("events_freezable",
5057 WQ_FREEZABLE, 0);
Viresh Kumar06681062013-04-24 17:12:54 +05305058 system_power_efficient_wq = alloc_workqueue("events_power_efficient",
5059 WQ_POWER_EFFICIENT, 0);
5060 system_freezable_power_efficient_wq = alloc_workqueue("events_freezable_power_efficient",
5061 WQ_FREEZABLE | WQ_POWER_EFFICIENT,
5062 0);
Joonsoo Kim1aabe902012-08-15 23:25:39 +09005063 BUG_ON(!system_wq || !system_highpri_wq || !system_long_wq ||
Viresh Kumar06681062013-04-24 17:12:54 +05305064 !system_unbound_wq || !system_freezable_wq ||
5065 !system_power_efficient_wq ||
5066 !system_freezable_power_efficient_wq);
Suresh Siddha6ee05782010-07-30 14:57:37 -07005067 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005068}
Suresh Siddha6ee05782010-07-30 14:57:37 -07005069early_initcall(init_workqueues);