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457c8996 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
1da177e4 | 2 | /* |
c54fce6e | 3 | * kernel/workqueue.c - generic async execution with shared worker pool |
1da177e4 | 4 | * |
c54fce6e | 5 | * Copyright (C) 2002 Ingo Molnar |
1da177e4 | 6 | * |
c54fce6e TH |
7 | * Derived from the taskqueue/keventd code by: |
8 | * David Woodhouse <dwmw2@infradead.org> | |
9 | * Andrew Morton | |
10 | * Kai Petzke <wpp@marie.physik.tu-berlin.de> | |
11 | * Theodore Ts'o <tytso@mit.edu> | |
1da177e4 | 12 | * |
c54fce6e | 13 | * Made to use alloc_percpu by Christoph Lameter. |
1da177e4 | 14 | * |
c54fce6e TH |
15 | * Copyright (C) 2010 SUSE Linux Products GmbH |
16 | * Copyright (C) 2010 Tejun Heo <tj@kernel.org> | |
89ada679 | 17 | * |
c54fce6e TH |
18 | * This is the generic async execution mechanism. Work items as are |
19 | * executed in process context. The worker pool is shared and | |
b11895c4 L |
20 | * automatically managed. There are two worker pools for each CPU (one for |
21 | * normal work items and the other for high priority ones) and some extra | |
22 | * pools for workqueues which are not bound to any specific CPU - the | |
23 | * number of these backing pools is dynamic. | |
c54fce6e | 24 | * |
9a261491 | 25 | * Please read Documentation/core-api/workqueue.rst for details. |
1da177e4 LT |
26 | */ |
27 | ||
9984de1a | 28 | #include <linux/export.h> |
1da177e4 LT |
29 | #include <linux/kernel.h> |
30 | #include <linux/sched.h> | |
31 | #include <linux/init.h> | |
32 | #include <linux/signal.h> | |
33 | #include <linux/completion.h> | |
34 | #include <linux/workqueue.h> | |
35 | #include <linux/slab.h> | |
36 | #include <linux/cpu.h> | |
37 | #include <linux/notifier.h> | |
38 | #include <linux/kthread.h> | |
1fa44eca | 39 | #include <linux/hardirq.h> |
46934023 | 40 | #include <linux/mempolicy.h> |
341a5958 | 41 | #include <linux/freezer.h> |
d5abe669 | 42 | #include <linux/debug_locks.h> |
4e6045f1 | 43 | #include <linux/lockdep.h> |
c34056a3 | 44 | #include <linux/idr.h> |
29c91e99 | 45 | #include <linux/jhash.h> |
42f8570f | 46 | #include <linux/hashtable.h> |
76af4d93 | 47 | #include <linux/rculist.h> |
bce90380 | 48 | #include <linux/nodemask.h> |
4c16bd32 | 49 | #include <linux/moduleparam.h> |
3d1cb205 | 50 | #include <linux/uaccess.h> |
c98a9805 | 51 | #include <linux/sched/isolation.h> |
cd2440d6 | 52 | #include <linux/sched/debug.h> |
62635ea8 | 53 | #include <linux/nmi.h> |
940d71c6 | 54 | #include <linux/kvm_para.h> |
aa6fde93 | 55 | #include <linux/delay.h> |
e22bee78 | 56 | |
ea138446 | 57 | #include "workqueue_internal.h" |
1da177e4 | 58 | |
c8e55f36 | 59 | enum { |
24647570 TH |
60 | /* |
61 | * worker_pool flags | |
bc2ae0f5 | 62 | * |
24647570 | 63 | * A bound pool is either associated or disassociated with its CPU. |
bc2ae0f5 TH |
64 | * While associated (!DISASSOCIATED), all workers are bound to the |
65 | * CPU and none has %WORKER_UNBOUND set and concurrency management | |
66 | * is in effect. | |
67 | * | |
68 | * While DISASSOCIATED, the cpu may be offline and all workers have | |
69 | * %WORKER_UNBOUND set and concurrency management disabled, and may | |
24647570 | 70 | * be executing on any CPU. The pool behaves as an unbound one. |
bc2ae0f5 | 71 | * |
bc3a1afc | 72 | * Note that DISASSOCIATED should be flipped only while holding |
1258fae7 | 73 | * wq_pool_attach_mutex to avoid changing binding state while |
4736cbf7 | 74 | * worker_attach_to_pool() is in progress. |
bc2ae0f5 | 75 | */ |
692b4825 | 76 | POOL_MANAGER_ACTIVE = 1 << 0, /* being managed */ |
24647570 | 77 | POOL_DISASSOCIATED = 1 << 2, /* cpu can't serve workers */ |
db7bccf4 | 78 | |
c8e55f36 | 79 | /* worker flags */ |
c8e55f36 TH |
80 | WORKER_DIE = 1 << 1, /* die die die */ |
81 | WORKER_IDLE = 1 << 2, /* is idle */ | |
e22bee78 | 82 | WORKER_PREP = 1 << 3, /* preparing to run works */ |
fb0e7beb | 83 | WORKER_CPU_INTENSIVE = 1 << 6, /* cpu intensive */ |
f3421797 | 84 | WORKER_UNBOUND = 1 << 7, /* worker is unbound */ |
a9ab775b | 85 | WORKER_REBOUND = 1 << 8, /* worker was rebound */ |
e22bee78 | 86 | |
a9ab775b TH |
87 | WORKER_NOT_RUNNING = WORKER_PREP | WORKER_CPU_INTENSIVE | |
88 | WORKER_UNBOUND | WORKER_REBOUND, | |
db7bccf4 | 89 | |
e34cdddb | 90 | NR_STD_WORKER_POOLS = 2, /* # standard pools per cpu */ |
4ce62e9e | 91 | |
29c91e99 | 92 | UNBOUND_POOL_HASH_ORDER = 6, /* hashed by pool->attrs */ |
c8e55f36 | 93 | BUSY_WORKER_HASH_ORDER = 6, /* 64 pointers */ |
db7bccf4 | 94 | |
e22bee78 TH |
95 | MAX_IDLE_WORKERS_RATIO = 4, /* 1/4 of busy can be idle */ |
96 | IDLE_WORKER_TIMEOUT = 300 * HZ, /* keep idle ones for 5 mins */ | |
97 | ||
3233cdbd TH |
98 | MAYDAY_INITIAL_TIMEOUT = HZ / 100 >= 2 ? HZ / 100 : 2, |
99 | /* call for help after 10ms | |
100 | (min two ticks) */ | |
e22bee78 TH |
101 | MAYDAY_INTERVAL = HZ / 10, /* and then every 100ms */ |
102 | CREATE_COOLDOWN = HZ, /* time to breath after fail */ | |
e22bee78 TH |
103 | |
104 | /* | |
105 | * Rescue workers are used only on emergencies and shared by | |
8698a745 | 106 | * all cpus. Give MIN_NICE. |
e22bee78 | 107 | */ |
8698a745 DY |
108 | RESCUER_NICE_LEVEL = MIN_NICE, |
109 | HIGHPRI_NICE_LEVEL = MIN_NICE, | |
ecf6881f TH |
110 | |
111 | WQ_NAME_LEN = 24, | |
c8e55f36 | 112 | }; |
1da177e4 LT |
113 | |
114 | /* | |
4690c4ab TH |
115 | * Structure fields follow one of the following exclusion rules. |
116 | * | |
e41e704b TH |
117 | * I: Modifiable by initialization/destruction paths and read-only for |
118 | * everyone else. | |
4690c4ab | 119 | * |
e22bee78 TH |
120 | * P: Preemption protected. Disabling preemption is enough and should |
121 | * only be modified and accessed from the local cpu. | |
122 | * | |
d565ed63 | 123 | * L: pool->lock protected. Access with pool->lock held. |
4690c4ab | 124 | * |
bdf8b9bf TH |
125 | * K: Only modified by worker while holding pool->lock. Can be safely read by |
126 | * self, while holding pool->lock or from IRQ context if %current is the | |
127 | * kworker. | |
128 | * | |
129 | * S: Only modified by worker self. | |
130 | * | |
1258fae7 | 131 | * A: wq_pool_attach_mutex protected. |
822d8405 | 132 | * |
68e13a67 | 133 | * PL: wq_pool_mutex protected. |
5bcab335 | 134 | * |
24acfb71 | 135 | * PR: wq_pool_mutex protected for writes. RCU protected for reads. |
76af4d93 | 136 | * |
5b95e1af LJ |
137 | * PW: wq_pool_mutex and wq->mutex protected for writes. Either for reads. |
138 | * | |
139 | * PWR: wq_pool_mutex and wq->mutex protected for writes. Either or | |
24acfb71 | 140 | * RCU for reads. |
5b95e1af | 141 | * |
3c25a55d LJ |
142 | * WQ: wq->mutex protected. |
143 | * | |
24acfb71 | 144 | * WR: wq->mutex protected for writes. RCU protected for reads. |
2e109a28 TH |
145 | * |
146 | * MD: wq_mayday_lock protected. | |
cd2440d6 PM |
147 | * |
148 | * WD: Used internally by the watchdog. | |
1da177e4 | 149 | */ |
1da177e4 | 150 | |
2eaebdb3 | 151 | /* struct worker is defined in workqueue_internal.h */ |
c34056a3 | 152 | |
bd7bdd43 | 153 | struct worker_pool { |
a9b8a985 | 154 | raw_spinlock_t lock; /* the pool lock */ |
d84ff051 | 155 | int cpu; /* I: the associated cpu */ |
f3f90ad4 | 156 | int node; /* I: the associated node ID */ |
9daf9e67 | 157 | int id; /* I: pool ID */ |
bc8b50c2 | 158 | unsigned int flags; /* L: flags */ |
bd7bdd43 | 159 | |
82607adc | 160 | unsigned long watchdog_ts; /* L: watchdog timestamp */ |
cd2440d6 | 161 | bool cpu_stall; /* WD: stalled cpu bound pool */ |
82607adc | 162 | |
bc35f7ef LJ |
163 | /* |
164 | * The counter is incremented in a process context on the associated CPU | |
165 | * w/ preemption disabled, and decremented or reset in the same context | |
166 | * but w/ pool->lock held. The readers grab pool->lock and are | |
167 | * guaranteed to see if the counter reached zero. | |
168 | */ | |
169 | int nr_running; | |
84f91c62 | 170 | |
bd7bdd43 | 171 | struct list_head worklist; /* L: list of pending works */ |
ea1abd61 | 172 | |
5826cc8f LJ |
173 | int nr_workers; /* L: total number of workers */ |
174 | int nr_idle; /* L: currently idle workers */ | |
bd7bdd43 | 175 | |
2c1f1a91 | 176 | struct list_head idle_list; /* L: list of idle workers */ |
bd7bdd43 | 177 | struct timer_list idle_timer; /* L: worker idle timeout */ |
3f959aa3 VS |
178 | struct work_struct idle_cull_work; /* L: worker idle cleanup */ |
179 | ||
180 | struct timer_list mayday_timer; /* L: SOS timer for workers */ | |
bd7bdd43 | 181 | |
c5aa87bb | 182 | /* a workers is either on busy_hash or idle_list, or the manager */ |
c9e7cf27 TH |
183 | DECLARE_HASHTABLE(busy_hash, BUSY_WORKER_HASH_ORDER); |
184 | /* L: hash of busy workers */ | |
185 | ||
2607d7a6 | 186 | struct worker *manager; /* L: purely informational */ |
92f9c5c4 | 187 | struct list_head workers; /* A: attached workers */ |
e02b9312 | 188 | struct list_head dying_workers; /* A: workers about to die */ |
60f5a4bc | 189 | struct completion *detach_completion; /* all workers detached */ |
e19e397a | 190 | |
7cda9aae | 191 | struct ida worker_ida; /* worker IDs for task name */ |
e19e397a | 192 | |
7a4e344c | 193 | struct workqueue_attrs *attrs; /* I: worker attributes */ |
68e13a67 LJ |
194 | struct hlist_node hash_node; /* PL: unbound_pool_hash node */ |
195 | int refcnt; /* PL: refcnt for unbound pools */ | |
7a4e344c | 196 | |
29c91e99 | 197 | /* |
24acfb71 | 198 | * Destruction of pool is RCU protected to allow dereferences |
29c91e99 TH |
199 | * from get_work_pool(). |
200 | */ | |
201 | struct rcu_head rcu; | |
84f91c62 | 202 | }; |
8b03ae3c | 203 | |
725e8ec5 TH |
204 | /* |
205 | * Per-pool_workqueue statistics. These can be monitored using | |
206 | * tools/workqueue/wq_monitor.py. | |
207 | */ | |
208 | enum pool_workqueue_stats { | |
209 | PWQ_STAT_STARTED, /* work items started execution */ | |
210 | PWQ_STAT_COMPLETED, /* work items completed execution */ | |
8a1dd1e5 | 211 | PWQ_STAT_CPU_TIME, /* total CPU time consumed */ |
616db877 | 212 | PWQ_STAT_CPU_INTENSIVE, /* wq_cpu_intensive_thresh_us violations */ |
725e8ec5 TH |
213 | PWQ_STAT_CM_WAKEUP, /* concurrency-management worker wakeups */ |
214 | PWQ_STAT_MAYDAY, /* maydays to rescuer */ | |
215 | PWQ_STAT_RESCUED, /* linked work items executed by rescuer */ | |
216 | ||
217 | PWQ_NR_STATS, | |
218 | }; | |
219 | ||
1da177e4 | 220 | /* |
112202d9 TH |
221 | * The per-pool workqueue. While queued, the lower WORK_STRUCT_FLAG_BITS |
222 | * of work_struct->data are used for flags and the remaining high bits | |
223 | * point to the pwq; thus, pwqs need to be aligned at two's power of the | |
224 | * number of flag bits. | |
1da177e4 | 225 | */ |
112202d9 | 226 | struct pool_workqueue { |
bd7bdd43 | 227 | struct worker_pool *pool; /* I: the associated pool */ |
4690c4ab | 228 | struct workqueue_struct *wq; /* I: the owning workqueue */ |
73f53c4a TH |
229 | int work_color; /* L: current color */ |
230 | int flush_color; /* L: flushing color */ | |
8864b4e5 | 231 | int refcnt; /* L: reference count */ |
73f53c4a TH |
232 | int nr_in_flight[WORK_NR_COLORS]; |
233 | /* L: nr of in_flight works */ | |
018f3a13 LJ |
234 | |
235 | /* | |
236 | * nr_active management and WORK_STRUCT_INACTIVE: | |
237 | * | |
238 | * When pwq->nr_active >= max_active, new work item is queued to | |
239 | * pwq->inactive_works instead of pool->worklist and marked with | |
240 | * WORK_STRUCT_INACTIVE. | |
241 | * | |
242 | * All work items marked with WORK_STRUCT_INACTIVE do not participate | |
243 | * in pwq->nr_active and all work items in pwq->inactive_works are | |
244 | * marked with WORK_STRUCT_INACTIVE. But not all WORK_STRUCT_INACTIVE | |
245 | * work items are in pwq->inactive_works. Some of them are ready to | |
246 | * run in pool->worklist or worker->scheduled. Those work itmes are | |
247 | * only struct wq_barrier which is used for flush_work() and should | |
248 | * not participate in pwq->nr_active. For non-barrier work item, it | |
249 | * is marked with WORK_STRUCT_INACTIVE iff it is in pwq->inactive_works. | |
250 | */ | |
1e19ffc6 | 251 | int nr_active; /* L: nr of active works */ |
a0a1a5fd | 252 | int max_active; /* L: max active works */ |
f97a4a1a | 253 | struct list_head inactive_works; /* L: inactive works */ |
3c25a55d | 254 | struct list_head pwqs_node; /* WR: node on wq->pwqs */ |
2e109a28 | 255 | struct list_head mayday_node; /* MD: node on wq->maydays */ |
8864b4e5 | 256 | |
725e8ec5 TH |
257 | u64 stats[PWQ_NR_STATS]; |
258 | ||
8864b4e5 | 259 | /* |
967b494e | 260 | * Release of unbound pwq is punted to a kthread_worker. See put_pwq() |
687a9aa5 TH |
261 | * and pwq_release_workfn() for details. pool_workqueue itself is also |
262 | * RCU protected so that the first pwq can be determined without | |
967b494e | 263 | * grabbing wq->mutex. |
8864b4e5 | 264 | */ |
687a9aa5 | 265 | struct kthread_work release_work; |
8864b4e5 | 266 | struct rcu_head rcu; |
e904e6c2 | 267 | } __aligned(1 << WORK_STRUCT_FLAG_BITS); |
1da177e4 | 268 | |
73f53c4a TH |
269 | /* |
270 | * Structure used to wait for workqueue flush. | |
271 | */ | |
272 | struct wq_flusher { | |
3c25a55d LJ |
273 | struct list_head list; /* WQ: list of flushers */ |
274 | int flush_color; /* WQ: flush color waiting for */ | |
73f53c4a TH |
275 | struct completion done; /* flush completion */ |
276 | }; | |
277 | ||
226223ab TH |
278 | struct wq_device; |
279 | ||
1da177e4 | 280 | /* |
c5aa87bb TH |
281 | * The externally visible workqueue. It relays the issued work items to |
282 | * the appropriate worker_pool through its pool_workqueues. | |
1da177e4 LT |
283 | */ |
284 | struct workqueue_struct { | |
3c25a55d | 285 | struct list_head pwqs; /* WR: all pwqs of this wq */ |
e2dca7ad | 286 | struct list_head list; /* PR: list of all workqueues */ |
73f53c4a | 287 | |
3c25a55d LJ |
288 | struct mutex mutex; /* protects this wq */ |
289 | int work_color; /* WQ: current work color */ | |
290 | int flush_color; /* WQ: current flush color */ | |
112202d9 | 291 | atomic_t nr_pwqs_to_flush; /* flush in progress */ |
3c25a55d LJ |
292 | struct wq_flusher *first_flusher; /* WQ: first flusher */ |
293 | struct list_head flusher_queue; /* WQ: flush waiters */ | |
294 | struct list_head flusher_overflow; /* WQ: flush overflow list */ | |
73f53c4a | 295 | |
2e109a28 | 296 | struct list_head maydays; /* MD: pwqs requesting rescue */ |
30ae2fc0 | 297 | struct worker *rescuer; /* MD: rescue worker */ |
e22bee78 | 298 | |
87fc741e | 299 | int nr_drainers; /* WQ: drain in progress */ |
a357fc03 | 300 | int saved_max_active; /* WQ: saved pwq max_active */ |
226223ab | 301 | |
5b95e1af LJ |
302 | struct workqueue_attrs *unbound_attrs; /* PW: only for unbound wqs */ |
303 | struct pool_workqueue *dfl_pwq; /* PW: only for unbound wqs */ | |
6029a918 | 304 | |
226223ab TH |
305 | #ifdef CONFIG_SYSFS |
306 | struct wq_device *wq_dev; /* I: for sysfs interface */ | |
307 | #endif | |
4e6045f1 | 308 | #ifdef CONFIG_LOCKDEP |
669de8bd BVA |
309 | char *lock_name; |
310 | struct lock_class_key key; | |
4690c4ab | 311 | struct lockdep_map lockdep_map; |
4e6045f1 | 312 | #endif |
ecf6881f | 313 | char name[WQ_NAME_LEN]; /* I: workqueue name */ |
2728fd2f | 314 | |
e2dca7ad | 315 | /* |
24acfb71 TG |
316 | * Destruction of workqueue_struct is RCU protected to allow walking |
317 | * the workqueues list without grabbing wq_pool_mutex. | |
e2dca7ad TH |
318 | * This is used to dump all workqueues from sysrq. |
319 | */ | |
320 | struct rcu_head rcu; | |
321 | ||
2728fd2f TH |
322 | /* hot fields used during command issue, aligned to cacheline */ |
323 | unsigned int flags ____cacheline_aligned; /* WQ: WQ_* flags */ | |
636b927e | 324 | struct pool_workqueue __percpu __rcu **cpu_pwq; /* I: per-cpu pwqs */ |
1da177e4 LT |
325 | }; |
326 | ||
e904e6c2 TH |
327 | static struct kmem_cache *pwq_cache; |
328 | ||
fef59c9c | 329 | static cpumask_var_t *wq_pod_cpus; /* possible CPUs of each node */ |
bce90380 | 330 | |
616db877 TH |
331 | /* |
332 | * Per-cpu work items which run for longer than the following threshold are | |
333 | * automatically considered CPU intensive and excluded from concurrency | |
334 | * management to prevent them from noticeably delaying other per-cpu work items. | |
aa6fde93 TH |
335 | * ULONG_MAX indicates that the user hasn't overridden it with a boot parameter. |
336 | * The actual value is initialized in wq_cpu_intensive_thresh_init(). | |
616db877 | 337 | */ |
aa6fde93 | 338 | static unsigned long wq_cpu_intensive_thresh_us = ULONG_MAX; |
616db877 TH |
339 | module_param_named(cpu_intensive_thresh_us, wq_cpu_intensive_thresh_us, ulong, 0644); |
340 | ||
cee22a15 | 341 | /* see the comment above the definition of WQ_POWER_EFFICIENT */ |
552f530c | 342 | static bool wq_power_efficient = IS_ENABLED(CONFIG_WQ_POWER_EFFICIENT_DEFAULT); |
cee22a15 VK |
343 | module_param_named(power_efficient, wq_power_efficient, bool, 0444); |
344 | ||
863b710b | 345 | static bool wq_online; /* can kworkers be created yet? */ |
3347fa09 | 346 | |
fef59c9c | 347 | static bool wq_pod_enabled; /* unbound CPU pod affinity enabled */ |
bce90380 | 348 | |
fef59c9c TH |
349 | /* buf for wq_update_unbound_pod_attrs(), protected by CPU hotplug exclusion */ |
350 | static struct workqueue_attrs *wq_update_pod_attrs_buf; | |
0f36ee24 | 351 | static cpumask_var_t wq_update_pod_cpumask_buf; |
4c16bd32 | 352 | |
68e13a67 | 353 | static DEFINE_MUTEX(wq_pool_mutex); /* protects pools and workqueues list */ |
1258fae7 | 354 | static DEFINE_MUTEX(wq_pool_attach_mutex); /* protects worker attach/detach */ |
a9b8a985 | 355 | static DEFINE_RAW_SPINLOCK(wq_mayday_lock); /* protects wq->maydays list */ |
d8bb65ab SAS |
356 | /* wait for manager to go away */ |
357 | static struct rcuwait manager_wait = __RCUWAIT_INITIALIZER(manager_wait); | |
5bcab335 | 358 | |
e2dca7ad | 359 | static LIST_HEAD(workqueues); /* PR: list of all workqueues */ |
68e13a67 | 360 | static bool workqueue_freezing; /* PL: have wqs started freezing? */ |
7d19c5ce | 361 | |
99c621ef | 362 | /* PL&A: allowable cpus for unbound wqs and work items */ |
ef557180 MG |
363 | static cpumask_var_t wq_unbound_cpumask; |
364 | ||
ace3c549 | 365 | /* for further constrain wq_unbound_cpumask by cmdline parameter*/ |
366 | static struct cpumask wq_cmdline_cpumask __initdata; | |
367 | ||
ef557180 MG |
368 | /* CPU where unbound work was last round robin scheduled from this CPU */ |
369 | static DEFINE_PER_CPU(int, wq_rr_cpu_last); | |
b05a7928 | 370 | |
f303fccb TH |
371 | /* |
372 | * Local execution of unbound work items is no longer guaranteed. The | |
373 | * following always forces round-robin CPU selection on unbound work items | |
374 | * to uncover usages which depend on it. | |
375 | */ | |
376 | #ifdef CONFIG_DEBUG_WQ_FORCE_RR_CPU | |
377 | static bool wq_debug_force_rr_cpu = true; | |
378 | #else | |
379 | static bool wq_debug_force_rr_cpu = false; | |
380 | #endif | |
381 | module_param_named(debug_force_rr_cpu, wq_debug_force_rr_cpu, bool, 0644); | |
382 | ||
7d19c5ce | 383 | /* the per-cpu worker pools */ |
25528213 | 384 | static DEFINE_PER_CPU_SHARED_ALIGNED(struct worker_pool [NR_STD_WORKER_POOLS], cpu_worker_pools); |
7d19c5ce | 385 | |
68e13a67 | 386 | static DEFINE_IDR(worker_pool_idr); /* PR: idr of all pools */ |
7d19c5ce | 387 | |
68e13a67 | 388 | /* PL: hash of all unbound pools keyed by pool->attrs */ |
29c91e99 TH |
389 | static DEFINE_HASHTABLE(unbound_pool_hash, UNBOUND_POOL_HASH_ORDER); |
390 | ||
c5aa87bb | 391 | /* I: attributes used when instantiating standard unbound pools on demand */ |
29c91e99 TH |
392 | static struct workqueue_attrs *unbound_std_wq_attrs[NR_STD_WORKER_POOLS]; |
393 | ||
8a2b7538 TH |
394 | /* I: attributes used when instantiating ordered pools on demand */ |
395 | static struct workqueue_attrs *ordered_wq_attrs[NR_STD_WORKER_POOLS]; | |
396 | ||
967b494e TH |
397 | /* |
398 | * I: kthread_worker to release pwq's. pwq release needs to be bounced to a | |
399 | * process context while holding a pool lock. Bounce to a dedicated kthread | |
400 | * worker to avoid A-A deadlocks. | |
401 | */ | |
402 | static struct kthread_worker *pwq_release_worker; | |
403 | ||
d320c038 | 404 | struct workqueue_struct *system_wq __read_mostly; |
ad7b1f84 | 405 | EXPORT_SYMBOL(system_wq); |
044c782c | 406 | struct workqueue_struct *system_highpri_wq __read_mostly; |
1aabe902 | 407 | EXPORT_SYMBOL_GPL(system_highpri_wq); |
044c782c | 408 | struct workqueue_struct *system_long_wq __read_mostly; |
d320c038 | 409 | EXPORT_SYMBOL_GPL(system_long_wq); |
044c782c | 410 | struct workqueue_struct *system_unbound_wq __read_mostly; |
f3421797 | 411 | EXPORT_SYMBOL_GPL(system_unbound_wq); |
044c782c | 412 | struct workqueue_struct *system_freezable_wq __read_mostly; |
24d51add | 413 | EXPORT_SYMBOL_GPL(system_freezable_wq); |
0668106c VK |
414 | struct workqueue_struct *system_power_efficient_wq __read_mostly; |
415 | EXPORT_SYMBOL_GPL(system_power_efficient_wq); | |
416 | struct workqueue_struct *system_freezable_power_efficient_wq __read_mostly; | |
417 | EXPORT_SYMBOL_GPL(system_freezable_power_efficient_wq); | |
d320c038 | 418 | |
7d19c5ce | 419 | static int worker_thread(void *__worker); |
6ba94429 | 420 | static void workqueue_sysfs_unregister(struct workqueue_struct *wq); |
c29eb853 | 421 | static void show_pwq(struct pool_workqueue *pwq); |
55df0933 | 422 | static void show_one_worker_pool(struct worker_pool *pool); |
7d19c5ce | 423 | |
97bd2347 TH |
424 | #define CREATE_TRACE_POINTS |
425 | #include <trace/events/workqueue.h> | |
426 | ||
68e13a67 | 427 | #define assert_rcu_or_pool_mutex() \ |
24acfb71 | 428 | RCU_LOCKDEP_WARN(!rcu_read_lock_held() && \ |
f78f5b90 | 429 | !lockdep_is_held(&wq_pool_mutex), \ |
24acfb71 | 430 | "RCU or wq_pool_mutex should be held") |
5bcab335 | 431 | |
5b95e1af | 432 | #define assert_rcu_or_wq_mutex_or_pool_mutex(wq) \ |
24acfb71 | 433 | RCU_LOCKDEP_WARN(!rcu_read_lock_held() && \ |
f78f5b90 PM |
434 | !lockdep_is_held(&wq->mutex) && \ |
435 | !lockdep_is_held(&wq_pool_mutex), \ | |
24acfb71 | 436 | "RCU, wq->mutex or wq_pool_mutex should be held") |
5b95e1af | 437 | |
f02ae73a TH |
438 | #define for_each_cpu_worker_pool(pool, cpu) \ |
439 | for ((pool) = &per_cpu(cpu_worker_pools, cpu)[0]; \ | |
440 | (pool) < &per_cpu(cpu_worker_pools, cpu)[NR_STD_WORKER_POOLS]; \ | |
7a62c2c8 | 441 | (pool)++) |
4ce62e9e | 442 | |
17116969 TH |
443 | /** |
444 | * for_each_pool - iterate through all worker_pools in the system | |
445 | * @pool: iteration cursor | |
611c92a0 | 446 | * @pi: integer used for iteration |
fa1b54e6 | 447 | * |
24acfb71 | 448 | * This must be called either with wq_pool_mutex held or RCU read |
68e13a67 LJ |
449 | * locked. If the pool needs to be used beyond the locking in effect, the |
450 | * caller is responsible for guaranteeing that the pool stays online. | |
fa1b54e6 TH |
451 | * |
452 | * The if/else clause exists only for the lockdep assertion and can be | |
453 | * ignored. | |
17116969 | 454 | */ |
611c92a0 TH |
455 | #define for_each_pool(pool, pi) \ |
456 | idr_for_each_entry(&worker_pool_idr, pool, pi) \ | |
68e13a67 | 457 | if (({ assert_rcu_or_pool_mutex(); false; })) { } \ |
fa1b54e6 | 458 | else |
17116969 | 459 | |
822d8405 TH |
460 | /** |
461 | * for_each_pool_worker - iterate through all workers of a worker_pool | |
462 | * @worker: iteration cursor | |
822d8405 TH |
463 | * @pool: worker_pool to iterate workers of |
464 | * | |
1258fae7 | 465 | * This must be called with wq_pool_attach_mutex. |
822d8405 TH |
466 | * |
467 | * The if/else clause exists only for the lockdep assertion and can be | |
468 | * ignored. | |
469 | */ | |
da028469 LJ |
470 | #define for_each_pool_worker(worker, pool) \ |
471 | list_for_each_entry((worker), &(pool)->workers, node) \ | |
1258fae7 | 472 | if (({ lockdep_assert_held(&wq_pool_attach_mutex); false; })) { } \ |
822d8405 TH |
473 | else |
474 | ||
49e3cf44 TH |
475 | /** |
476 | * for_each_pwq - iterate through all pool_workqueues of the specified workqueue | |
477 | * @pwq: iteration cursor | |
478 | * @wq: the target workqueue | |
76af4d93 | 479 | * |
24acfb71 | 480 | * This must be called either with wq->mutex held or RCU read locked. |
794b18bc TH |
481 | * If the pwq needs to be used beyond the locking in effect, the caller is |
482 | * responsible for guaranteeing that the pwq stays online. | |
76af4d93 TH |
483 | * |
484 | * The if/else clause exists only for the lockdep assertion and can be | |
485 | * ignored. | |
49e3cf44 TH |
486 | */ |
487 | #define for_each_pwq(pwq, wq) \ | |
49e9d1a9 | 488 | list_for_each_entry_rcu((pwq), &(wq)->pwqs, pwqs_node, \ |
5a644662 | 489 | lockdep_is_held(&(wq->mutex))) |
f3421797 | 490 | |
dc186ad7 TG |
491 | #ifdef CONFIG_DEBUG_OBJECTS_WORK |
492 | ||
f9e62f31 | 493 | static const struct debug_obj_descr work_debug_descr; |
dc186ad7 | 494 | |
99777288 SG |
495 | static void *work_debug_hint(void *addr) |
496 | { | |
497 | return ((struct work_struct *) addr)->func; | |
498 | } | |
499 | ||
b9fdac7f DC |
500 | static bool work_is_static_object(void *addr) |
501 | { | |
502 | struct work_struct *work = addr; | |
503 | ||
504 | return test_bit(WORK_STRUCT_STATIC_BIT, work_data_bits(work)); | |
505 | } | |
506 | ||
dc186ad7 TG |
507 | /* |
508 | * fixup_init is called when: | |
509 | * - an active object is initialized | |
510 | */ | |
02a982a6 | 511 | static bool work_fixup_init(void *addr, enum debug_obj_state state) |
dc186ad7 TG |
512 | { |
513 | struct work_struct *work = addr; | |
514 | ||
515 | switch (state) { | |
516 | case ODEBUG_STATE_ACTIVE: | |
517 | cancel_work_sync(work); | |
518 | debug_object_init(work, &work_debug_descr); | |
02a982a6 | 519 | return true; |
dc186ad7 | 520 | default: |
02a982a6 | 521 | return false; |
dc186ad7 TG |
522 | } |
523 | } | |
524 | ||
dc186ad7 TG |
525 | /* |
526 | * fixup_free is called when: | |
527 | * - an active object is freed | |
528 | */ | |
02a982a6 | 529 | static bool work_fixup_free(void *addr, enum debug_obj_state state) |
dc186ad7 TG |
530 | { |
531 | struct work_struct *work = addr; | |
532 | ||
533 | switch (state) { | |
534 | case ODEBUG_STATE_ACTIVE: | |
535 | cancel_work_sync(work); | |
536 | debug_object_free(work, &work_debug_descr); | |
02a982a6 | 537 | return true; |
dc186ad7 | 538 | default: |
02a982a6 | 539 | return false; |
dc186ad7 TG |
540 | } |
541 | } | |
542 | ||
f9e62f31 | 543 | static const struct debug_obj_descr work_debug_descr = { |
dc186ad7 | 544 | .name = "work_struct", |
99777288 | 545 | .debug_hint = work_debug_hint, |
b9fdac7f | 546 | .is_static_object = work_is_static_object, |
dc186ad7 | 547 | .fixup_init = work_fixup_init, |
dc186ad7 TG |
548 | .fixup_free = work_fixup_free, |
549 | }; | |
550 | ||
551 | static inline void debug_work_activate(struct work_struct *work) | |
552 | { | |
553 | debug_object_activate(work, &work_debug_descr); | |
554 | } | |
555 | ||
556 | static inline void debug_work_deactivate(struct work_struct *work) | |
557 | { | |
558 | debug_object_deactivate(work, &work_debug_descr); | |
559 | } | |
560 | ||
561 | void __init_work(struct work_struct *work, int onstack) | |
562 | { | |
563 | if (onstack) | |
564 | debug_object_init_on_stack(work, &work_debug_descr); | |
565 | else | |
566 | debug_object_init(work, &work_debug_descr); | |
567 | } | |
568 | EXPORT_SYMBOL_GPL(__init_work); | |
569 | ||
570 | void destroy_work_on_stack(struct work_struct *work) | |
571 | { | |
572 | debug_object_free(work, &work_debug_descr); | |
573 | } | |
574 | EXPORT_SYMBOL_GPL(destroy_work_on_stack); | |
575 | ||
ea2e64f2 TG |
576 | void destroy_delayed_work_on_stack(struct delayed_work *work) |
577 | { | |
578 | destroy_timer_on_stack(&work->timer); | |
579 | debug_object_free(&work->work, &work_debug_descr); | |
580 | } | |
581 | EXPORT_SYMBOL_GPL(destroy_delayed_work_on_stack); | |
582 | ||
dc186ad7 TG |
583 | #else |
584 | static inline void debug_work_activate(struct work_struct *work) { } | |
585 | static inline void debug_work_deactivate(struct work_struct *work) { } | |
586 | #endif | |
587 | ||
4e8b22bd | 588 | /** |
67dc8325 | 589 | * worker_pool_assign_id - allocate ID and assign it to @pool |
4e8b22bd LB |
590 | * @pool: the pool pointer of interest |
591 | * | |
592 | * Returns 0 if ID in [0, WORK_OFFQ_POOL_NONE) is allocated and assigned | |
593 | * successfully, -errno on failure. | |
594 | */ | |
9daf9e67 TH |
595 | static int worker_pool_assign_id(struct worker_pool *pool) |
596 | { | |
597 | int ret; | |
598 | ||
68e13a67 | 599 | lockdep_assert_held(&wq_pool_mutex); |
5bcab335 | 600 | |
4e8b22bd LB |
601 | ret = idr_alloc(&worker_pool_idr, pool, 0, WORK_OFFQ_POOL_NONE, |
602 | GFP_KERNEL); | |
229641a6 | 603 | if (ret >= 0) { |
e68035fb | 604 | pool->id = ret; |
229641a6 TH |
605 | return 0; |
606 | } | |
fa1b54e6 | 607 | return ret; |
7c3eed5c TH |
608 | } |
609 | ||
73f53c4a TH |
610 | static unsigned int work_color_to_flags(int color) |
611 | { | |
612 | return color << WORK_STRUCT_COLOR_SHIFT; | |
613 | } | |
614 | ||
c4560c2c | 615 | static int get_work_color(unsigned long work_data) |
73f53c4a | 616 | { |
c4560c2c | 617 | return (work_data >> WORK_STRUCT_COLOR_SHIFT) & |
73f53c4a TH |
618 | ((1 << WORK_STRUCT_COLOR_BITS) - 1); |
619 | } | |
620 | ||
621 | static int work_next_color(int color) | |
622 | { | |
623 | return (color + 1) % WORK_NR_COLORS; | |
624 | } | |
1da177e4 | 625 | |
14441960 | 626 | /* |
112202d9 TH |
627 | * While queued, %WORK_STRUCT_PWQ is set and non flag bits of a work's data |
628 | * contain the pointer to the queued pwq. Once execution starts, the flag | |
7c3eed5c | 629 | * is cleared and the high bits contain OFFQ flags and pool ID. |
7a22ad75 | 630 | * |
112202d9 TH |
631 | * set_work_pwq(), set_work_pool_and_clear_pending(), mark_work_canceling() |
632 | * and clear_work_data() can be used to set the pwq, pool or clear | |
bbb68dfa TH |
633 | * work->data. These functions should only be called while the work is |
634 | * owned - ie. while the PENDING bit is set. | |
7a22ad75 | 635 | * |
112202d9 | 636 | * get_work_pool() and get_work_pwq() can be used to obtain the pool or pwq |
7c3eed5c | 637 | * corresponding to a work. Pool is available once the work has been |
112202d9 | 638 | * queued anywhere after initialization until it is sync canceled. pwq is |
7c3eed5c | 639 | * available only while the work item is queued. |
7a22ad75 | 640 | * |
bbb68dfa TH |
641 | * %WORK_OFFQ_CANCELING is used to mark a work item which is being |
642 | * canceled. While being canceled, a work item may have its PENDING set | |
643 | * but stay off timer and worklist for arbitrarily long and nobody should | |
644 | * try to steal the PENDING bit. | |
14441960 | 645 | */ |
7a22ad75 TH |
646 | static inline void set_work_data(struct work_struct *work, unsigned long data, |
647 | unsigned long flags) | |
365970a1 | 648 | { |
6183c009 | 649 | WARN_ON_ONCE(!work_pending(work)); |
7a22ad75 TH |
650 | atomic_long_set(&work->data, data | flags | work_static(work)); |
651 | } | |
365970a1 | 652 | |
112202d9 | 653 | static void set_work_pwq(struct work_struct *work, struct pool_workqueue *pwq, |
7a22ad75 TH |
654 | unsigned long extra_flags) |
655 | { | |
112202d9 TH |
656 | set_work_data(work, (unsigned long)pwq, |
657 | WORK_STRUCT_PENDING | WORK_STRUCT_PWQ | extra_flags); | |
365970a1 DH |
658 | } |
659 | ||
4468a00f LJ |
660 | static void set_work_pool_and_keep_pending(struct work_struct *work, |
661 | int pool_id) | |
662 | { | |
663 | set_work_data(work, (unsigned long)pool_id << WORK_OFFQ_POOL_SHIFT, | |
664 | WORK_STRUCT_PENDING); | |
665 | } | |
666 | ||
7c3eed5c TH |
667 | static void set_work_pool_and_clear_pending(struct work_struct *work, |
668 | int pool_id) | |
7a22ad75 | 669 | { |
23657bb1 TH |
670 | /* |
671 | * The following wmb is paired with the implied mb in | |
672 | * test_and_set_bit(PENDING) and ensures all updates to @work made | |
673 | * here are visible to and precede any updates by the next PENDING | |
674 | * owner. | |
675 | */ | |
676 | smp_wmb(); | |
7c3eed5c | 677 | set_work_data(work, (unsigned long)pool_id << WORK_OFFQ_POOL_SHIFT, 0); |
346c09f8 RP |
678 | /* |
679 | * The following mb guarantees that previous clear of a PENDING bit | |
680 | * will not be reordered with any speculative LOADS or STORES from | |
681 | * work->current_func, which is executed afterwards. This possible | |
8bdc6201 | 682 | * reordering can lead to a missed execution on attempt to queue |
346c09f8 RP |
683 | * the same @work. E.g. consider this case: |
684 | * | |
685 | * CPU#0 CPU#1 | |
686 | * ---------------------------- -------------------------------- | |
687 | * | |
688 | * 1 STORE event_indicated | |
689 | * 2 queue_work_on() { | |
690 | * 3 test_and_set_bit(PENDING) | |
691 | * 4 } set_..._and_clear_pending() { | |
692 | * 5 set_work_data() # clear bit | |
693 | * 6 smp_mb() | |
694 | * 7 work->current_func() { | |
695 | * 8 LOAD event_indicated | |
696 | * } | |
697 | * | |
698 | * Without an explicit full barrier speculative LOAD on line 8 can | |
699 | * be executed before CPU#0 does STORE on line 1. If that happens, | |
700 | * CPU#0 observes the PENDING bit is still set and new execution of | |
701 | * a @work is not queued in a hope, that CPU#1 will eventually | |
702 | * finish the queued @work. Meanwhile CPU#1 does not see | |
703 | * event_indicated is set, because speculative LOAD was executed | |
704 | * before actual STORE. | |
705 | */ | |
706 | smp_mb(); | |
7a22ad75 | 707 | } |
f756d5e2 | 708 | |
7a22ad75 | 709 | static void clear_work_data(struct work_struct *work) |
1da177e4 | 710 | { |
7c3eed5c TH |
711 | smp_wmb(); /* see set_work_pool_and_clear_pending() */ |
712 | set_work_data(work, WORK_STRUCT_NO_POOL, 0); | |
1da177e4 LT |
713 | } |
714 | ||
afa4bb77 LT |
715 | static inline struct pool_workqueue *work_struct_pwq(unsigned long data) |
716 | { | |
717 | return (struct pool_workqueue *)(data & WORK_STRUCT_WQ_DATA_MASK); | |
718 | } | |
719 | ||
112202d9 | 720 | static struct pool_workqueue *get_work_pwq(struct work_struct *work) |
b1f4ec17 | 721 | { |
e120153d | 722 | unsigned long data = atomic_long_read(&work->data); |
7a22ad75 | 723 | |
112202d9 | 724 | if (data & WORK_STRUCT_PWQ) |
afa4bb77 | 725 | return work_struct_pwq(data); |
e120153d TH |
726 | else |
727 | return NULL; | |
4d707b9f ON |
728 | } |
729 | ||
7c3eed5c TH |
730 | /** |
731 | * get_work_pool - return the worker_pool a given work was associated with | |
732 | * @work: the work item of interest | |
733 | * | |
68e13a67 | 734 | * Pools are created and destroyed under wq_pool_mutex, and allows read |
24acfb71 TG |
735 | * access under RCU read lock. As such, this function should be |
736 | * called under wq_pool_mutex or inside of a rcu_read_lock() region. | |
fa1b54e6 TH |
737 | * |
738 | * All fields of the returned pool are accessible as long as the above | |
739 | * mentioned locking is in effect. If the returned pool needs to be used | |
740 | * beyond the critical section, the caller is responsible for ensuring the | |
741 | * returned pool is and stays online. | |
d185af30 YB |
742 | * |
743 | * Return: The worker_pool @work was last associated with. %NULL if none. | |
7c3eed5c TH |
744 | */ |
745 | static struct worker_pool *get_work_pool(struct work_struct *work) | |
365970a1 | 746 | { |
e120153d | 747 | unsigned long data = atomic_long_read(&work->data); |
7c3eed5c | 748 | int pool_id; |
7a22ad75 | 749 | |
68e13a67 | 750 | assert_rcu_or_pool_mutex(); |
fa1b54e6 | 751 | |
112202d9 | 752 | if (data & WORK_STRUCT_PWQ) |
afa4bb77 | 753 | return work_struct_pwq(data)->pool; |
7a22ad75 | 754 | |
7c3eed5c TH |
755 | pool_id = data >> WORK_OFFQ_POOL_SHIFT; |
756 | if (pool_id == WORK_OFFQ_POOL_NONE) | |
7a22ad75 TH |
757 | return NULL; |
758 | ||
fa1b54e6 | 759 | return idr_find(&worker_pool_idr, pool_id); |
7c3eed5c TH |
760 | } |
761 | ||
762 | /** | |
763 | * get_work_pool_id - return the worker pool ID a given work is associated with | |
764 | * @work: the work item of interest | |
765 | * | |
d185af30 | 766 | * Return: The worker_pool ID @work was last associated with. |
7c3eed5c TH |
767 | * %WORK_OFFQ_POOL_NONE if none. |
768 | */ | |
769 | static int get_work_pool_id(struct work_struct *work) | |
770 | { | |
54d5b7d0 LJ |
771 | unsigned long data = atomic_long_read(&work->data); |
772 | ||
112202d9 | 773 | if (data & WORK_STRUCT_PWQ) |
afa4bb77 | 774 | return work_struct_pwq(data)->pool->id; |
7c3eed5c | 775 | |
54d5b7d0 | 776 | return data >> WORK_OFFQ_POOL_SHIFT; |
7c3eed5c TH |
777 | } |
778 | ||
bbb68dfa TH |
779 | static void mark_work_canceling(struct work_struct *work) |
780 | { | |
7c3eed5c | 781 | unsigned long pool_id = get_work_pool_id(work); |
bbb68dfa | 782 | |
7c3eed5c TH |
783 | pool_id <<= WORK_OFFQ_POOL_SHIFT; |
784 | set_work_data(work, pool_id | WORK_OFFQ_CANCELING, WORK_STRUCT_PENDING); | |
bbb68dfa TH |
785 | } |
786 | ||
787 | static bool work_is_canceling(struct work_struct *work) | |
788 | { | |
789 | unsigned long data = atomic_long_read(&work->data); | |
790 | ||
112202d9 | 791 | return !(data & WORK_STRUCT_PWQ) && (data & WORK_OFFQ_CANCELING); |
bbb68dfa TH |
792 | } |
793 | ||
e22bee78 | 794 | /* |
3270476a TH |
795 | * Policy functions. These define the policies on how the global worker |
796 | * pools are managed. Unless noted otherwise, these functions assume that | |
d565ed63 | 797 | * they're being called with pool->lock held. |
e22bee78 TH |
798 | */ |
799 | ||
63d95a91 | 800 | static bool __need_more_worker(struct worker_pool *pool) |
a848e3b6 | 801 | { |
bc35f7ef | 802 | return !pool->nr_running; |
a848e3b6 ON |
803 | } |
804 | ||
4594bf15 | 805 | /* |
e22bee78 TH |
806 | * Need to wake up a worker? Called from anything but currently |
807 | * running workers. | |
974271c4 TH |
808 | * |
809 | * Note that, because unbound workers never contribute to nr_running, this | |
706026c2 | 810 | * function will always return %true for unbound pools as long as the |
974271c4 | 811 | * worklist isn't empty. |
4594bf15 | 812 | */ |
63d95a91 | 813 | static bool need_more_worker(struct worker_pool *pool) |
365970a1 | 814 | { |
63d95a91 | 815 | return !list_empty(&pool->worklist) && __need_more_worker(pool); |
e22bee78 | 816 | } |
4594bf15 | 817 | |
e22bee78 | 818 | /* Can I start working? Called from busy but !running workers. */ |
63d95a91 | 819 | static bool may_start_working(struct worker_pool *pool) |
e22bee78 | 820 | { |
63d95a91 | 821 | return pool->nr_idle; |
e22bee78 TH |
822 | } |
823 | ||
824 | /* Do I need to keep working? Called from currently running workers. */ | |
63d95a91 | 825 | static bool keep_working(struct worker_pool *pool) |
e22bee78 | 826 | { |
bc35f7ef | 827 | return !list_empty(&pool->worklist) && (pool->nr_running <= 1); |
e22bee78 TH |
828 | } |
829 | ||
830 | /* Do we need a new worker? Called from manager. */ | |
63d95a91 | 831 | static bool need_to_create_worker(struct worker_pool *pool) |
e22bee78 | 832 | { |
63d95a91 | 833 | return need_more_worker(pool) && !may_start_working(pool); |
e22bee78 | 834 | } |
365970a1 | 835 | |
e22bee78 | 836 | /* Do we have too many workers and should some go away? */ |
63d95a91 | 837 | static bool too_many_workers(struct worker_pool *pool) |
e22bee78 | 838 | { |
692b4825 | 839 | bool managing = pool->flags & POOL_MANAGER_ACTIVE; |
63d95a91 TH |
840 | int nr_idle = pool->nr_idle + managing; /* manager is considered idle */ |
841 | int nr_busy = pool->nr_workers - nr_idle; | |
e22bee78 TH |
842 | |
843 | return nr_idle > 2 && (nr_idle - 2) * MAX_IDLE_WORKERS_RATIO >= nr_busy; | |
365970a1 DH |
844 | } |
845 | ||
c54d5046 TH |
846 | /** |
847 | * worker_set_flags - set worker flags and adjust nr_running accordingly | |
848 | * @worker: self | |
849 | * @flags: flags to set | |
850 | * | |
851 | * Set @flags in @worker->flags and adjust nr_running accordingly. | |
c54d5046 TH |
852 | */ |
853 | static inline void worker_set_flags(struct worker *worker, unsigned int flags) | |
854 | { | |
855 | struct worker_pool *pool = worker->pool; | |
856 | ||
bc8b50c2 | 857 | lockdep_assert_held(&pool->lock); |
c54d5046 TH |
858 | |
859 | /* If transitioning into NOT_RUNNING, adjust nr_running. */ | |
860 | if ((flags & WORKER_NOT_RUNNING) && | |
861 | !(worker->flags & WORKER_NOT_RUNNING)) { | |
862 | pool->nr_running--; | |
863 | } | |
864 | ||
865 | worker->flags |= flags; | |
866 | } | |
867 | ||
868 | /** | |
869 | * worker_clr_flags - clear worker flags and adjust nr_running accordingly | |
870 | * @worker: self | |
871 | * @flags: flags to clear | |
872 | * | |
873 | * Clear @flags in @worker->flags and adjust nr_running accordingly. | |
c54d5046 TH |
874 | */ |
875 | static inline void worker_clr_flags(struct worker *worker, unsigned int flags) | |
876 | { | |
877 | struct worker_pool *pool = worker->pool; | |
878 | unsigned int oflags = worker->flags; | |
879 | ||
bc8b50c2 | 880 | lockdep_assert_held(&pool->lock); |
c54d5046 TH |
881 | |
882 | worker->flags &= ~flags; | |
883 | ||
884 | /* | |
885 | * If transitioning out of NOT_RUNNING, increment nr_running. Note | |
886 | * that the nested NOT_RUNNING is not a noop. NOT_RUNNING is mask | |
887 | * of multiple flags, not a single flag. | |
888 | */ | |
889 | if ((flags & WORKER_NOT_RUNNING) && (oflags & WORKER_NOT_RUNNING)) | |
890 | if (!(worker->flags & WORKER_NOT_RUNNING)) | |
891 | pool->nr_running++; | |
892 | } | |
893 | ||
797e8345 TH |
894 | /* Return the first idle worker. Called with pool->lock held. */ |
895 | static struct worker *first_idle_worker(struct worker_pool *pool) | |
896 | { | |
897 | if (unlikely(list_empty(&pool->idle_list))) | |
898 | return NULL; | |
899 | ||
900 | return list_first_entry(&pool->idle_list, struct worker, entry); | |
901 | } | |
902 | ||
903 | /** | |
904 | * worker_enter_idle - enter idle state | |
905 | * @worker: worker which is entering idle state | |
906 | * | |
907 | * @worker is entering idle state. Update stats and idle timer if | |
908 | * necessary. | |
909 | * | |
910 | * LOCKING: | |
911 | * raw_spin_lock_irq(pool->lock). | |
912 | */ | |
913 | static void worker_enter_idle(struct worker *worker) | |
914 | { | |
915 | struct worker_pool *pool = worker->pool; | |
916 | ||
917 | if (WARN_ON_ONCE(worker->flags & WORKER_IDLE) || | |
918 | WARN_ON_ONCE(!list_empty(&worker->entry) && | |
919 | (worker->hentry.next || worker->hentry.pprev))) | |
920 | return; | |
921 | ||
922 | /* can't use worker_set_flags(), also called from create_worker() */ | |
923 | worker->flags |= WORKER_IDLE; | |
924 | pool->nr_idle++; | |
925 | worker->last_active = jiffies; | |
926 | ||
927 | /* idle_list is LIFO */ | |
928 | list_add(&worker->entry, &pool->idle_list); | |
929 | ||
930 | if (too_many_workers(pool) && !timer_pending(&pool->idle_timer)) | |
931 | mod_timer(&pool->idle_timer, jiffies + IDLE_WORKER_TIMEOUT); | |
932 | ||
933 | /* Sanity check nr_running. */ | |
934 | WARN_ON_ONCE(pool->nr_workers == pool->nr_idle && pool->nr_running); | |
935 | } | |
936 | ||
937 | /** | |
938 | * worker_leave_idle - leave idle state | |
939 | * @worker: worker which is leaving idle state | |
940 | * | |
941 | * @worker is leaving idle state. Update stats. | |
942 | * | |
943 | * LOCKING: | |
944 | * raw_spin_lock_irq(pool->lock). | |
945 | */ | |
946 | static void worker_leave_idle(struct worker *worker) | |
947 | { | |
948 | struct worker_pool *pool = worker->pool; | |
949 | ||
950 | if (WARN_ON_ONCE(!(worker->flags & WORKER_IDLE))) | |
951 | return; | |
952 | worker_clr_flags(worker, WORKER_IDLE); | |
953 | pool->nr_idle--; | |
954 | list_del_init(&worker->entry); | |
955 | } | |
956 | ||
957 | /** | |
958 | * find_worker_executing_work - find worker which is executing a work | |
959 | * @pool: pool of interest | |
960 | * @work: work to find worker for | |
961 | * | |
962 | * Find a worker which is executing @work on @pool by searching | |
963 | * @pool->busy_hash which is keyed by the address of @work. For a worker | |
964 | * to match, its current execution should match the address of @work and | |
965 | * its work function. This is to avoid unwanted dependency between | |
966 | * unrelated work executions through a work item being recycled while still | |
967 | * being executed. | |
968 | * | |
969 | * This is a bit tricky. A work item may be freed once its execution | |
970 | * starts and nothing prevents the freed area from being recycled for | |
971 | * another work item. If the same work item address ends up being reused | |
972 | * before the original execution finishes, workqueue will identify the | |
973 | * recycled work item as currently executing and make it wait until the | |
974 | * current execution finishes, introducing an unwanted dependency. | |
975 | * | |
976 | * This function checks the work item address and work function to avoid | |
977 | * false positives. Note that this isn't complete as one may construct a | |
978 | * work function which can introduce dependency onto itself through a | |
979 | * recycled work item. Well, if somebody wants to shoot oneself in the | |
980 | * foot that badly, there's only so much we can do, and if such deadlock | |
981 | * actually occurs, it should be easy to locate the culprit work function. | |
982 | * | |
983 | * CONTEXT: | |
984 | * raw_spin_lock_irq(pool->lock). | |
985 | * | |
986 | * Return: | |
987 | * Pointer to worker which is executing @work if found, %NULL | |
988 | * otherwise. | |
989 | */ | |
990 | static struct worker *find_worker_executing_work(struct worker_pool *pool, | |
991 | struct work_struct *work) | |
992 | { | |
993 | struct worker *worker; | |
994 | ||
995 | hash_for_each_possible(pool->busy_hash, worker, hentry, | |
996 | (unsigned long)work) | |
997 | if (worker->current_work == work && | |
998 | worker->current_func == work->func) | |
999 | return worker; | |
1000 | ||
1001 | return NULL; | |
1002 | } | |
1003 | ||
1004 | /** | |
1005 | * move_linked_works - move linked works to a list | |
1006 | * @work: start of series of works to be scheduled | |
1007 | * @head: target list to append @work to | |
1008 | * @nextp: out parameter for nested worklist walking | |
1009 | * | |
1010 | * Schedule linked works starting from @work to @head. Work series to | |
1011 | * be scheduled starts at @work and includes any consecutive work with | |
1012 | * WORK_STRUCT_LINKED set in its predecessor. | |
1013 | * | |
1014 | * If @nextp is not NULL, it's updated to point to the next work of | |
1015 | * the last scheduled work. This allows move_linked_works() to be | |
1016 | * nested inside outer list_for_each_entry_safe(). | |
1017 | * | |
1018 | * CONTEXT: | |
1019 | * raw_spin_lock_irq(pool->lock). | |
1020 | */ | |
1021 | static void move_linked_works(struct work_struct *work, struct list_head *head, | |
1022 | struct work_struct **nextp) | |
1023 | { | |
1024 | struct work_struct *n; | |
1025 | ||
1026 | /* | |
1027 | * Linked worklist will always end before the end of the list, | |
1028 | * use NULL for list head. | |
1029 | */ | |
1030 | list_for_each_entry_safe_from(work, n, NULL, entry) { | |
1031 | list_move_tail(&work->entry, head); | |
1032 | if (!(*work_data_bits(work) & WORK_STRUCT_LINKED)) | |
1033 | break; | |
1034 | } | |
1035 | ||
1036 | /* | |
1037 | * If we're already inside safe list traversal and have moved | |
1038 | * multiple works to the scheduled queue, the next position | |
1039 | * needs to be updated. | |
1040 | */ | |
1041 | if (nextp) | |
1042 | *nextp = n; | |
1043 | } | |
1044 | ||
1045 | /** | |
1046 | * wake_up_worker - wake up an idle worker | |
1047 | * @pool: worker pool to wake worker from | |
1048 | * | |
1049 | * Wake up the first idle worker of @pool. | |
1050 | * | |
1051 | * CONTEXT: | |
1052 | * raw_spin_lock_irq(pool->lock). | |
1053 | */ | |
1054 | static void wake_up_worker(struct worker_pool *pool) | |
1055 | { | |
1056 | struct worker *worker = first_idle_worker(pool); | |
1057 | ||
1058 | if (likely(worker)) | |
1059 | wake_up_process(worker->task); | |
1060 | } | |
1061 | ||
63638450 TH |
1062 | #ifdef CONFIG_WQ_CPU_INTENSIVE_REPORT |
1063 | ||
1064 | /* | |
1065 | * Concurrency-managed per-cpu work items that hog CPU for longer than | |
1066 | * wq_cpu_intensive_thresh_us trigger the automatic CPU_INTENSIVE mechanism, | |
1067 | * which prevents them from stalling other concurrency-managed work items. If a | |
1068 | * work function keeps triggering this mechanism, it's likely that the work item | |
1069 | * should be using an unbound workqueue instead. | |
1070 | * | |
1071 | * wq_cpu_intensive_report() tracks work functions which trigger such conditions | |
1072 | * and report them so that they can be examined and converted to use unbound | |
1073 | * workqueues as appropriate. To avoid flooding the console, each violating work | |
1074 | * function is tracked and reported with exponential backoff. | |
1075 | */ | |
1076 | #define WCI_MAX_ENTS 128 | |
1077 | ||
1078 | struct wci_ent { | |
1079 | work_func_t func; | |
1080 | atomic64_t cnt; | |
1081 | struct hlist_node hash_node; | |
1082 | }; | |
1083 | ||
1084 | static struct wci_ent wci_ents[WCI_MAX_ENTS]; | |
1085 | static int wci_nr_ents; | |
1086 | static DEFINE_RAW_SPINLOCK(wci_lock); | |
1087 | static DEFINE_HASHTABLE(wci_hash, ilog2(WCI_MAX_ENTS)); | |
1088 | ||
1089 | static struct wci_ent *wci_find_ent(work_func_t func) | |
1090 | { | |
1091 | struct wci_ent *ent; | |
1092 | ||
1093 | hash_for_each_possible_rcu(wci_hash, ent, hash_node, | |
1094 | (unsigned long)func) { | |
1095 | if (ent->func == func) | |
1096 | return ent; | |
1097 | } | |
1098 | return NULL; | |
1099 | } | |
1100 | ||
1101 | static void wq_cpu_intensive_report(work_func_t func) | |
1102 | { | |
1103 | struct wci_ent *ent; | |
1104 | ||
1105 | restart: | |
1106 | ent = wci_find_ent(func); | |
1107 | if (ent) { | |
1108 | u64 cnt; | |
1109 | ||
1110 | /* | |
1111 | * Start reporting from the fourth time and back off | |
1112 | * exponentially. | |
1113 | */ | |
1114 | cnt = atomic64_inc_return_relaxed(&ent->cnt); | |
1115 | if (cnt >= 4 && is_power_of_2(cnt)) | |
1116 | printk_deferred(KERN_WARNING "workqueue: %ps hogged CPU for >%luus %llu times, consider switching to WQ_UNBOUND\n", | |
1117 | ent->func, wq_cpu_intensive_thresh_us, | |
1118 | atomic64_read(&ent->cnt)); | |
1119 | return; | |
1120 | } | |
1121 | ||
1122 | /* | |
1123 | * @func is a new violation. Allocate a new entry for it. If wcn_ents[] | |
1124 | * is exhausted, something went really wrong and we probably made enough | |
1125 | * noise already. | |
1126 | */ | |
1127 | if (wci_nr_ents >= WCI_MAX_ENTS) | |
1128 | return; | |
1129 | ||
1130 | raw_spin_lock(&wci_lock); | |
1131 | ||
1132 | if (wci_nr_ents >= WCI_MAX_ENTS) { | |
1133 | raw_spin_unlock(&wci_lock); | |
1134 | return; | |
1135 | } | |
1136 | ||
1137 | if (wci_find_ent(func)) { | |
1138 | raw_spin_unlock(&wci_lock); | |
1139 | goto restart; | |
1140 | } | |
1141 | ||
1142 | ent = &wci_ents[wci_nr_ents++]; | |
1143 | ent->func = func; | |
1144 | atomic64_set(&ent->cnt, 1); | |
1145 | hash_add_rcu(wci_hash, &ent->hash_node, (unsigned long)func); | |
1146 | ||
1147 | raw_spin_unlock(&wci_lock); | |
1148 | } | |
1149 | ||
1150 | #else /* CONFIG_WQ_CPU_INTENSIVE_REPORT */ | |
1151 | static void wq_cpu_intensive_report(work_func_t func) {} | |
1152 | #endif /* CONFIG_WQ_CPU_INTENSIVE_REPORT */ | |
1153 | ||
d302f017 | 1154 | /** |
6d25be57 | 1155 | * wq_worker_running - a worker is running again |
e22bee78 | 1156 | * @task: task waking up |
e22bee78 | 1157 | * |
6d25be57 | 1158 | * This function is called when a worker returns from schedule() |
e22bee78 | 1159 | */ |
6d25be57 | 1160 | void wq_worker_running(struct task_struct *task) |
e22bee78 TH |
1161 | { |
1162 | struct worker *worker = kthread_data(task); | |
1163 | ||
c8f6219b | 1164 | if (!READ_ONCE(worker->sleeping)) |
6d25be57 | 1165 | return; |
07edfece FW |
1166 | |
1167 | /* | |
1168 | * If preempted by unbind_workers() between the WORKER_NOT_RUNNING check | |
1169 | * and the nr_running increment below, we may ruin the nr_running reset | |
1170 | * and leave with an unexpected pool->nr_running == 1 on the newly unbound | |
1171 | * pool. Protect against such race. | |
1172 | */ | |
1173 | preempt_disable(); | |
6d25be57 | 1174 | if (!(worker->flags & WORKER_NOT_RUNNING)) |
bc35f7ef | 1175 | worker->pool->nr_running++; |
07edfece | 1176 | preempt_enable(); |
616db877 TH |
1177 | |
1178 | /* | |
1179 | * CPU intensive auto-detection cares about how long a work item hogged | |
1180 | * CPU without sleeping. Reset the starting timestamp on wakeup. | |
1181 | */ | |
1182 | worker->current_at = worker->task->se.sum_exec_runtime; | |
1183 | ||
c8f6219b | 1184 | WRITE_ONCE(worker->sleeping, 0); |
e22bee78 TH |
1185 | } |
1186 | ||
1187 | /** | |
1188 | * wq_worker_sleeping - a worker is going to sleep | |
1189 | * @task: task going to sleep | |
e22bee78 | 1190 | * |
6d25be57 | 1191 | * This function is called from schedule() when a busy worker is |
ccf45156 | 1192 | * going to sleep. |
e22bee78 | 1193 | */ |
6d25be57 | 1194 | void wq_worker_sleeping(struct task_struct *task) |
e22bee78 | 1195 | { |
cc5bff38 | 1196 | struct worker *worker = kthread_data(task); |
111c225a | 1197 | struct worker_pool *pool; |
e22bee78 | 1198 | |
111c225a TH |
1199 | /* |
1200 | * Rescuers, which may not have all the fields set up like normal | |
1201 | * workers, also reach here, let's not access anything before | |
1202 | * checking NOT_RUNNING. | |
1203 | */ | |
2d64672e | 1204 | if (worker->flags & WORKER_NOT_RUNNING) |
6d25be57 | 1205 | return; |
e22bee78 | 1206 | |
111c225a | 1207 | pool = worker->pool; |
111c225a | 1208 | |
62849a96 | 1209 | /* Return if preempted before wq_worker_running() was reached */ |
c8f6219b | 1210 | if (READ_ONCE(worker->sleeping)) |
6d25be57 TG |
1211 | return; |
1212 | ||
c8f6219b | 1213 | WRITE_ONCE(worker->sleeping, 1); |
a9b8a985 | 1214 | raw_spin_lock_irq(&pool->lock); |
e22bee78 | 1215 | |
45c753f5 FW |
1216 | /* |
1217 | * Recheck in case unbind_workers() preempted us. We don't | |
1218 | * want to decrement nr_running after the worker is unbound | |
1219 | * and nr_running has been reset. | |
1220 | */ | |
1221 | if (worker->flags & WORKER_NOT_RUNNING) { | |
1222 | raw_spin_unlock_irq(&pool->lock); | |
1223 | return; | |
1224 | } | |
1225 | ||
bc35f7ef | 1226 | pool->nr_running--; |
725e8ec5 TH |
1227 | if (need_more_worker(pool)) { |
1228 | worker->current_pwq->stats[PWQ_STAT_CM_WAKEUP]++; | |
cc5bff38 | 1229 | wake_up_worker(pool); |
725e8ec5 | 1230 | } |
a9b8a985 | 1231 | raw_spin_unlock_irq(&pool->lock); |
e22bee78 TH |
1232 | } |
1233 | ||
616db877 TH |
1234 | /** |
1235 | * wq_worker_tick - a scheduler tick occurred while a kworker is running | |
1236 | * @task: task currently running | |
1237 | * | |
1238 | * Called from scheduler_tick(). We're in the IRQ context and the current | |
1239 | * worker's fields which follow the 'K' locking rule can be accessed safely. | |
1240 | */ | |
1241 | void wq_worker_tick(struct task_struct *task) | |
1242 | { | |
1243 | struct worker *worker = kthread_data(task); | |
1244 | struct pool_workqueue *pwq = worker->current_pwq; | |
1245 | struct worker_pool *pool = worker->pool; | |
1246 | ||
1247 | if (!pwq) | |
1248 | return; | |
1249 | ||
8a1dd1e5 TH |
1250 | pwq->stats[PWQ_STAT_CPU_TIME] += TICK_USEC; |
1251 | ||
18c8ae81 Z |
1252 | if (!wq_cpu_intensive_thresh_us) |
1253 | return; | |
1254 | ||
616db877 TH |
1255 | /* |
1256 | * If the current worker is concurrency managed and hogged the CPU for | |
1257 | * longer than wq_cpu_intensive_thresh_us, it's automatically marked | |
1258 | * CPU_INTENSIVE to avoid stalling other concurrency-managed work items. | |
c8f6219b Z |
1259 | * |
1260 | * Set @worker->sleeping means that @worker is in the process of | |
1261 | * switching out voluntarily and won't be contributing to | |
1262 | * @pool->nr_running until it wakes up. As wq_worker_sleeping() also | |
1263 | * decrements ->nr_running, setting CPU_INTENSIVE here can lead to | |
1264 | * double decrements. The task is releasing the CPU anyway. Let's skip. | |
1265 | * We probably want to make this prettier in the future. | |
616db877 | 1266 | */ |
c8f6219b | 1267 | if ((worker->flags & WORKER_NOT_RUNNING) || READ_ONCE(worker->sleeping) || |
616db877 TH |
1268 | worker->task->se.sum_exec_runtime - worker->current_at < |
1269 | wq_cpu_intensive_thresh_us * NSEC_PER_USEC) | |
1270 | return; | |
1271 | ||
1272 | raw_spin_lock(&pool->lock); | |
1273 | ||
1274 | worker_set_flags(worker, WORKER_CPU_INTENSIVE); | |
63638450 | 1275 | wq_cpu_intensive_report(worker->current_func); |
616db877 TH |
1276 | pwq->stats[PWQ_STAT_CPU_INTENSIVE]++; |
1277 | ||
1278 | if (need_more_worker(pool)) { | |
1279 | pwq->stats[PWQ_STAT_CM_WAKEUP]++; | |
1280 | wake_up_worker(pool); | |
1281 | } | |
1282 | ||
1283 | raw_spin_unlock(&pool->lock); | |
1284 | } | |
1285 | ||
1b69ac6b JW |
1286 | /** |
1287 | * wq_worker_last_func - retrieve worker's last work function | |
8194fe94 | 1288 | * @task: Task to retrieve last work function of. |
1b69ac6b JW |
1289 | * |
1290 | * Determine the last function a worker executed. This is called from | |
1291 | * the scheduler to get a worker's last known identity. | |
1292 | * | |
1293 | * CONTEXT: | |
a9b8a985 | 1294 | * raw_spin_lock_irq(rq->lock) |
1b69ac6b | 1295 | * |
4b047002 JW |
1296 | * This function is called during schedule() when a kworker is going |
1297 | * to sleep. It's used by psi to identify aggregation workers during | |
1298 | * dequeuing, to allow periodic aggregation to shut-off when that | |
1299 | * worker is the last task in the system or cgroup to go to sleep. | |
1300 | * | |
1301 | * As this function doesn't involve any workqueue-related locking, it | |
1302 | * only returns stable values when called from inside the scheduler's | |
1303 | * queuing and dequeuing paths, when @task, which must be a kworker, | |
1304 | * is guaranteed to not be processing any works. | |
1305 | * | |
1b69ac6b JW |
1306 | * Return: |
1307 | * The last work function %current executed as a worker, NULL if it | |
1308 | * hasn't executed any work yet. | |
1309 | */ | |
1310 | work_func_t wq_worker_last_func(struct task_struct *task) | |
1311 | { | |
1312 | struct worker *worker = kthread_data(task); | |
1313 | ||
1314 | return worker->last_func; | |
1315 | } | |
1316 | ||
8864b4e5 TH |
1317 | /** |
1318 | * get_pwq - get an extra reference on the specified pool_workqueue | |
1319 | * @pwq: pool_workqueue to get | |
1320 | * | |
1321 | * Obtain an extra reference on @pwq. The caller should guarantee that | |
1322 | * @pwq has positive refcnt and be holding the matching pool->lock. | |
1323 | */ | |
1324 | static void get_pwq(struct pool_workqueue *pwq) | |
1325 | { | |
1326 | lockdep_assert_held(&pwq->pool->lock); | |
1327 | WARN_ON_ONCE(pwq->refcnt <= 0); | |
1328 | pwq->refcnt++; | |
1329 | } | |
1330 | ||
1331 | /** | |
1332 | * put_pwq - put a pool_workqueue reference | |
1333 | * @pwq: pool_workqueue to put | |
1334 | * | |
1335 | * Drop a reference of @pwq. If its refcnt reaches zero, schedule its | |
1336 | * destruction. The caller should be holding the matching pool->lock. | |
1337 | */ | |
1338 | static void put_pwq(struct pool_workqueue *pwq) | |
1339 | { | |
1340 | lockdep_assert_held(&pwq->pool->lock); | |
1341 | if (likely(--pwq->refcnt)) | |
1342 | return; | |
8864b4e5 | 1343 | /* |
967b494e TH |
1344 | * @pwq can't be released under pool->lock, bounce to a dedicated |
1345 | * kthread_worker to avoid A-A deadlocks. | |
8864b4e5 | 1346 | */ |
687a9aa5 | 1347 | kthread_queue_work(pwq_release_worker, &pwq->release_work); |
8864b4e5 TH |
1348 | } |
1349 | ||
dce90d47 TH |
1350 | /** |
1351 | * put_pwq_unlocked - put_pwq() with surrounding pool lock/unlock | |
1352 | * @pwq: pool_workqueue to put (can be %NULL) | |
1353 | * | |
1354 | * put_pwq() with locking. This function also allows %NULL @pwq. | |
1355 | */ | |
1356 | static void put_pwq_unlocked(struct pool_workqueue *pwq) | |
1357 | { | |
1358 | if (pwq) { | |
1359 | /* | |
24acfb71 | 1360 | * As both pwqs and pools are RCU protected, the |
dce90d47 TH |
1361 | * following lock operations are safe. |
1362 | */ | |
a9b8a985 | 1363 | raw_spin_lock_irq(&pwq->pool->lock); |
dce90d47 | 1364 | put_pwq(pwq); |
a9b8a985 | 1365 | raw_spin_unlock_irq(&pwq->pool->lock); |
dce90d47 TH |
1366 | } |
1367 | } | |
1368 | ||
f97a4a1a | 1369 | static void pwq_activate_inactive_work(struct work_struct *work) |
bf4ede01 | 1370 | { |
112202d9 | 1371 | struct pool_workqueue *pwq = get_work_pwq(work); |
bf4ede01 TH |
1372 | |
1373 | trace_workqueue_activate_work(work); | |
82607adc TH |
1374 | if (list_empty(&pwq->pool->worklist)) |
1375 | pwq->pool->watchdog_ts = jiffies; | |
112202d9 | 1376 | move_linked_works(work, &pwq->pool->worklist, NULL); |
f97a4a1a | 1377 | __clear_bit(WORK_STRUCT_INACTIVE_BIT, work_data_bits(work)); |
112202d9 | 1378 | pwq->nr_active++; |
bf4ede01 TH |
1379 | } |
1380 | ||
f97a4a1a | 1381 | static void pwq_activate_first_inactive(struct pool_workqueue *pwq) |
3aa62497 | 1382 | { |
f97a4a1a | 1383 | struct work_struct *work = list_first_entry(&pwq->inactive_works, |
3aa62497 LJ |
1384 | struct work_struct, entry); |
1385 | ||
f97a4a1a | 1386 | pwq_activate_inactive_work(work); |
3aa62497 LJ |
1387 | } |
1388 | ||
bf4ede01 | 1389 | /** |
112202d9 TH |
1390 | * pwq_dec_nr_in_flight - decrement pwq's nr_in_flight |
1391 | * @pwq: pwq of interest | |
c4560c2c | 1392 | * @work_data: work_data of work which left the queue |
bf4ede01 TH |
1393 | * |
1394 | * A work either has completed or is removed from pending queue, | |
112202d9 | 1395 | * decrement nr_in_flight of its pwq and handle workqueue flushing. |
bf4ede01 TH |
1396 | * |
1397 | * CONTEXT: | |
a9b8a985 | 1398 | * raw_spin_lock_irq(pool->lock). |
bf4ede01 | 1399 | */ |
c4560c2c | 1400 | static void pwq_dec_nr_in_flight(struct pool_workqueue *pwq, unsigned long work_data) |
bf4ede01 | 1401 | { |
c4560c2c LJ |
1402 | int color = get_work_color(work_data); |
1403 | ||
018f3a13 LJ |
1404 | if (!(work_data & WORK_STRUCT_INACTIVE)) { |
1405 | pwq->nr_active--; | |
1406 | if (!list_empty(&pwq->inactive_works)) { | |
1407 | /* one down, submit an inactive one */ | |
1408 | if (pwq->nr_active < pwq->max_active) | |
1409 | pwq_activate_first_inactive(pwq); | |
1410 | } | |
1411 | } | |
1412 | ||
112202d9 | 1413 | pwq->nr_in_flight[color]--; |
bf4ede01 | 1414 | |
bf4ede01 | 1415 | /* is flush in progress and are we at the flushing tip? */ |
112202d9 | 1416 | if (likely(pwq->flush_color != color)) |
8864b4e5 | 1417 | goto out_put; |
bf4ede01 TH |
1418 | |
1419 | /* are there still in-flight works? */ | |
112202d9 | 1420 | if (pwq->nr_in_flight[color]) |
8864b4e5 | 1421 | goto out_put; |
bf4ede01 | 1422 | |
112202d9 TH |
1423 | /* this pwq is done, clear flush_color */ |
1424 | pwq->flush_color = -1; | |
bf4ede01 TH |
1425 | |
1426 | /* | |
112202d9 | 1427 | * If this was the last pwq, wake up the first flusher. It |
bf4ede01 TH |
1428 | * will handle the rest. |
1429 | */ | |
112202d9 TH |
1430 | if (atomic_dec_and_test(&pwq->wq->nr_pwqs_to_flush)) |
1431 | complete(&pwq->wq->first_flusher->done); | |
8864b4e5 TH |
1432 | out_put: |
1433 | put_pwq(pwq); | |
bf4ede01 TH |
1434 | } |
1435 | ||
36e227d2 | 1436 | /** |
bbb68dfa | 1437 | * try_to_grab_pending - steal work item from worklist and disable irq |
36e227d2 TH |
1438 | * @work: work item to steal |
1439 | * @is_dwork: @work is a delayed_work | |
bbb68dfa | 1440 | * @flags: place to store irq state |
36e227d2 TH |
1441 | * |
1442 | * Try to grab PENDING bit of @work. This function can handle @work in any | |
d185af30 | 1443 | * stable state - idle, on timer or on worklist. |
36e227d2 | 1444 | * |
d185af30 | 1445 | * Return: |
3eb6b31b MCC |
1446 | * |
1447 | * ======== ================================================================ | |
36e227d2 TH |
1448 | * 1 if @work was pending and we successfully stole PENDING |
1449 | * 0 if @work was idle and we claimed PENDING | |
1450 | * -EAGAIN if PENDING couldn't be grabbed at the moment, safe to busy-retry | |
bbb68dfa TH |
1451 | * -ENOENT if someone else is canceling @work, this state may persist |
1452 | * for arbitrarily long | |
3eb6b31b | 1453 | * ======== ================================================================ |
36e227d2 | 1454 | * |
d185af30 | 1455 | * Note: |
bbb68dfa | 1456 | * On >= 0 return, the caller owns @work's PENDING bit. To avoid getting |
e0aecdd8 TH |
1457 | * interrupted while holding PENDING and @work off queue, irq must be |
1458 | * disabled on entry. This, combined with delayed_work->timer being | |
1459 | * irqsafe, ensures that we return -EAGAIN for finite short period of time. | |
bbb68dfa TH |
1460 | * |
1461 | * On successful return, >= 0, irq is disabled and the caller is | |
1462 | * responsible for releasing it using local_irq_restore(*@flags). | |
1463 | * | |
e0aecdd8 | 1464 | * This function is safe to call from any context including IRQ handler. |
bf4ede01 | 1465 | */ |
bbb68dfa TH |
1466 | static int try_to_grab_pending(struct work_struct *work, bool is_dwork, |
1467 | unsigned long *flags) | |
bf4ede01 | 1468 | { |
d565ed63 | 1469 | struct worker_pool *pool; |
112202d9 | 1470 | struct pool_workqueue *pwq; |
bf4ede01 | 1471 | |
bbb68dfa TH |
1472 | local_irq_save(*flags); |
1473 | ||
36e227d2 TH |
1474 | /* try to steal the timer if it exists */ |
1475 | if (is_dwork) { | |
1476 | struct delayed_work *dwork = to_delayed_work(work); | |
1477 | ||
e0aecdd8 TH |
1478 | /* |
1479 | * dwork->timer is irqsafe. If del_timer() fails, it's | |
1480 | * guaranteed that the timer is not queued anywhere and not | |
1481 | * running on the local CPU. | |
1482 | */ | |
36e227d2 TH |
1483 | if (likely(del_timer(&dwork->timer))) |
1484 | return 1; | |
1485 | } | |
1486 | ||
1487 | /* try to claim PENDING the normal way */ | |
bf4ede01 TH |
1488 | if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) |
1489 | return 0; | |
1490 | ||
24acfb71 | 1491 | rcu_read_lock(); |
bf4ede01 TH |
1492 | /* |
1493 | * The queueing is in progress, or it is already queued. Try to | |
1494 | * steal it from ->worklist without clearing WORK_STRUCT_PENDING. | |
1495 | */ | |
d565ed63 TH |
1496 | pool = get_work_pool(work); |
1497 | if (!pool) | |
bbb68dfa | 1498 | goto fail; |
bf4ede01 | 1499 | |
a9b8a985 | 1500 | raw_spin_lock(&pool->lock); |
0b3dae68 | 1501 | /* |
112202d9 TH |
1502 | * work->data is guaranteed to point to pwq only while the work |
1503 | * item is queued on pwq->wq, and both updating work->data to point | |
1504 | * to pwq on queueing and to pool on dequeueing are done under | |
1505 | * pwq->pool->lock. This in turn guarantees that, if work->data | |
1506 | * points to pwq which is associated with a locked pool, the work | |
0b3dae68 LJ |
1507 | * item is currently queued on that pool. |
1508 | */ | |
112202d9 TH |
1509 | pwq = get_work_pwq(work); |
1510 | if (pwq && pwq->pool == pool) { | |
16062836 TH |
1511 | debug_work_deactivate(work); |
1512 | ||
1513 | /* | |
018f3a13 LJ |
1514 | * A cancelable inactive work item must be in the |
1515 | * pwq->inactive_works since a queued barrier can't be | |
1516 | * canceled (see the comments in insert_wq_barrier()). | |
1517 | * | |
f97a4a1a | 1518 | * An inactive work item cannot be grabbed directly because |
d812796e | 1519 | * it might have linked barrier work items which, if left |
f97a4a1a | 1520 | * on the inactive_works list, will confuse pwq->nr_active |
16062836 TH |
1521 | * management later on and cause stall. Make sure the work |
1522 | * item is activated before grabbing. | |
1523 | */ | |
f97a4a1a LJ |
1524 | if (*work_data_bits(work) & WORK_STRUCT_INACTIVE) |
1525 | pwq_activate_inactive_work(work); | |
16062836 TH |
1526 | |
1527 | list_del_init(&work->entry); | |
c4560c2c | 1528 | pwq_dec_nr_in_flight(pwq, *work_data_bits(work)); |
16062836 | 1529 | |
112202d9 | 1530 | /* work->data points to pwq iff queued, point to pool */ |
16062836 TH |
1531 | set_work_pool_and_keep_pending(work, pool->id); |
1532 | ||
a9b8a985 | 1533 | raw_spin_unlock(&pool->lock); |
24acfb71 | 1534 | rcu_read_unlock(); |
16062836 | 1535 | return 1; |
bf4ede01 | 1536 | } |
a9b8a985 | 1537 | raw_spin_unlock(&pool->lock); |
bbb68dfa | 1538 | fail: |
24acfb71 | 1539 | rcu_read_unlock(); |
bbb68dfa TH |
1540 | local_irq_restore(*flags); |
1541 | if (work_is_canceling(work)) | |
1542 | return -ENOENT; | |
1543 | cpu_relax(); | |
36e227d2 | 1544 | return -EAGAIN; |
bf4ede01 TH |
1545 | } |
1546 | ||
4690c4ab | 1547 | /** |
706026c2 | 1548 | * insert_work - insert a work into a pool |
112202d9 | 1549 | * @pwq: pwq @work belongs to |
4690c4ab TH |
1550 | * @work: work to insert |
1551 | * @head: insertion point | |
1552 | * @extra_flags: extra WORK_STRUCT_* flags to set | |
1553 | * | |
112202d9 | 1554 | * Insert @work which belongs to @pwq after @head. @extra_flags is or'd to |
706026c2 | 1555 | * work_struct flags. |
4690c4ab TH |
1556 | * |
1557 | * CONTEXT: | |
a9b8a985 | 1558 | * raw_spin_lock_irq(pool->lock). |
4690c4ab | 1559 | */ |
112202d9 TH |
1560 | static void insert_work(struct pool_workqueue *pwq, struct work_struct *work, |
1561 | struct list_head *head, unsigned int extra_flags) | |
b89deed3 | 1562 | { |
fe089f87 | 1563 | debug_work_activate(work); |
e22bee78 | 1564 | |
e89a85d6 | 1565 | /* record the work call stack in order to print it in KASAN reports */ |
f70da745 | 1566 | kasan_record_aux_stack_noalloc(work); |
e89a85d6 | 1567 | |
4690c4ab | 1568 | /* we own @work, set data and link */ |
112202d9 | 1569 | set_work_pwq(work, pwq, extra_flags); |
1a4d9b0a | 1570 | list_add_tail(&work->entry, head); |
8864b4e5 | 1571 | get_pwq(pwq); |
b89deed3 ON |
1572 | } |
1573 | ||
c8efcc25 TH |
1574 | /* |
1575 | * Test whether @work is being queued from another work executing on the | |
8d03ecfe | 1576 | * same workqueue. |
c8efcc25 TH |
1577 | */ |
1578 | static bool is_chained_work(struct workqueue_struct *wq) | |
1579 | { | |
8d03ecfe TH |
1580 | struct worker *worker; |
1581 | ||
1582 | worker = current_wq_worker(); | |
1583 | /* | |
bf393fd4 | 1584 | * Return %true iff I'm a worker executing a work item on @wq. If |
8d03ecfe TH |
1585 | * I'm @worker, it's safe to dereference it without locking. |
1586 | */ | |
112202d9 | 1587 | return worker && worker->current_pwq->wq == wq; |
c8efcc25 TH |
1588 | } |
1589 | ||
ef557180 MG |
1590 | /* |
1591 | * When queueing an unbound work item to a wq, prefer local CPU if allowed | |
1592 | * by wq_unbound_cpumask. Otherwise, round robin among the allowed ones to | |
1593 | * avoid perturbing sensitive tasks. | |
1594 | */ | |
1595 | static int wq_select_unbound_cpu(int cpu) | |
1596 | { | |
1597 | int new_cpu; | |
1598 | ||
f303fccb TH |
1599 | if (likely(!wq_debug_force_rr_cpu)) { |
1600 | if (cpumask_test_cpu(cpu, wq_unbound_cpumask)) | |
1601 | return cpu; | |
a8ec5880 AF |
1602 | } else { |
1603 | pr_warn_once("workqueue: round-robin CPU selection forced, expect performance impact\n"); | |
f303fccb TH |
1604 | } |
1605 | ||
ef557180 MG |
1606 | if (cpumask_empty(wq_unbound_cpumask)) |
1607 | return cpu; | |
1608 | ||
1609 | new_cpu = __this_cpu_read(wq_rr_cpu_last); | |
1610 | new_cpu = cpumask_next_and(new_cpu, wq_unbound_cpumask, cpu_online_mask); | |
1611 | if (unlikely(new_cpu >= nr_cpu_ids)) { | |
1612 | new_cpu = cpumask_first_and(wq_unbound_cpumask, cpu_online_mask); | |
1613 | if (unlikely(new_cpu >= nr_cpu_ids)) | |
1614 | return cpu; | |
1615 | } | |
1616 | __this_cpu_write(wq_rr_cpu_last, new_cpu); | |
1617 | ||
1618 | return new_cpu; | |
1619 | } | |
1620 | ||
d84ff051 | 1621 | static void __queue_work(int cpu, struct workqueue_struct *wq, |
1da177e4 LT |
1622 | struct work_struct *work) |
1623 | { | |
112202d9 | 1624 | struct pool_workqueue *pwq; |
fe089f87 | 1625 | struct worker_pool *last_pool, *pool; |
8a2e8e5d | 1626 | unsigned int work_flags; |
b75cac93 | 1627 | unsigned int req_cpu = cpu; |
8930caba TH |
1628 | |
1629 | /* | |
1630 | * While a work item is PENDING && off queue, a task trying to | |
1631 | * steal the PENDING will busy-loop waiting for it to either get | |
1632 | * queued or lose PENDING. Grabbing PENDING and queueing should | |
1633 | * happen with IRQ disabled. | |
1634 | */ | |
8e8eb730 | 1635 | lockdep_assert_irqs_disabled(); |
1da177e4 | 1636 | |
1e19ffc6 | 1637 | |
33e3f0a3 RC |
1638 | /* |
1639 | * For a draining wq, only works from the same workqueue are | |
1640 | * allowed. The __WQ_DESTROYING helps to spot the issue that | |
1641 | * queues a new work item to a wq after destroy_workqueue(wq). | |
1642 | */ | |
1643 | if (unlikely(wq->flags & (__WQ_DESTROYING | __WQ_DRAINING) && | |
1644 | WARN_ON_ONCE(!is_chained_work(wq)))) | |
e41e704b | 1645 | return; |
24acfb71 | 1646 | rcu_read_lock(); |
9e8cd2f5 | 1647 | retry: |
c9178087 | 1648 | /* pwq which will be used unless @work is executing elsewhere */ |
636b927e TH |
1649 | if (req_cpu == WORK_CPU_UNBOUND) { |
1650 | if (wq->flags & WQ_UNBOUND) | |
aa202f1f | 1651 | cpu = wq_select_unbound_cpu(raw_smp_processor_id()); |
636b927e | 1652 | else |
aa202f1f | 1653 | cpu = raw_smp_processor_id(); |
aa202f1f | 1654 | } |
dbf2576e | 1655 | |
636b927e | 1656 | pwq = rcu_dereference(*per_cpu_ptr(wq->cpu_pwq, cpu)); |
fe089f87 TH |
1657 | pool = pwq->pool; |
1658 | ||
c9178087 TH |
1659 | /* |
1660 | * If @work was previously on a different pool, it might still be | |
1661 | * running there, in which case the work needs to be queued on that | |
1662 | * pool to guarantee non-reentrancy. | |
1663 | */ | |
1664 | last_pool = get_work_pool(work); | |
fe089f87 | 1665 | if (last_pool && last_pool != pool) { |
c9178087 | 1666 | struct worker *worker; |
18aa9eff | 1667 | |
a9b8a985 | 1668 | raw_spin_lock(&last_pool->lock); |
18aa9eff | 1669 | |
c9178087 | 1670 | worker = find_worker_executing_work(last_pool, work); |
18aa9eff | 1671 | |
c9178087 TH |
1672 | if (worker && worker->current_pwq->wq == wq) { |
1673 | pwq = worker->current_pwq; | |
fe089f87 TH |
1674 | pool = pwq->pool; |
1675 | WARN_ON_ONCE(pool != last_pool); | |
8930caba | 1676 | } else { |
c9178087 | 1677 | /* meh... not running there, queue here */ |
a9b8a985 | 1678 | raw_spin_unlock(&last_pool->lock); |
fe089f87 | 1679 | raw_spin_lock(&pool->lock); |
8930caba | 1680 | } |
f3421797 | 1681 | } else { |
fe089f87 | 1682 | raw_spin_lock(&pool->lock); |
502ca9d8 TH |
1683 | } |
1684 | ||
9e8cd2f5 | 1685 | /* |
636b927e TH |
1686 | * pwq is determined and locked. For unbound pools, we could have raced |
1687 | * with pwq release and it could already be dead. If its refcnt is zero, | |
1688 | * repeat pwq selection. Note that unbound pwqs never die without | |
1689 | * another pwq replacing it in cpu_pwq or while work items are executing | |
1690 | * on it, so the retrying is guaranteed to make forward-progress. | |
9e8cd2f5 TH |
1691 | */ |
1692 | if (unlikely(!pwq->refcnt)) { | |
1693 | if (wq->flags & WQ_UNBOUND) { | |
fe089f87 | 1694 | raw_spin_unlock(&pool->lock); |
9e8cd2f5 TH |
1695 | cpu_relax(); |
1696 | goto retry; | |
1697 | } | |
1698 | /* oops */ | |
1699 | WARN_ONCE(true, "workqueue: per-cpu pwq for %s on cpu%d has 0 refcnt", | |
1700 | wq->name, cpu); | |
1701 | } | |
1702 | ||
112202d9 TH |
1703 | /* pwq determined, queue */ |
1704 | trace_workqueue_queue_work(req_cpu, pwq, work); | |
502ca9d8 | 1705 | |
24acfb71 TG |
1706 | if (WARN_ON(!list_empty(&work->entry))) |
1707 | goto out; | |
1e19ffc6 | 1708 | |
112202d9 TH |
1709 | pwq->nr_in_flight[pwq->work_color]++; |
1710 | work_flags = work_color_to_flags(pwq->work_color); | |
1e19ffc6 | 1711 | |
112202d9 | 1712 | if (likely(pwq->nr_active < pwq->max_active)) { |
fe089f87 TH |
1713 | if (list_empty(&pool->worklist)) |
1714 | pool->watchdog_ts = jiffies; | |
1715 | ||
cdadf009 | 1716 | trace_workqueue_activate_work(work); |
112202d9 | 1717 | pwq->nr_active++; |
fe089f87 TH |
1718 | insert_work(pwq, work, &pool->worklist, work_flags); |
1719 | ||
1720 | if (__need_more_worker(pool)) | |
1721 | wake_up_worker(pool); | |
8a2e8e5d | 1722 | } else { |
f97a4a1a | 1723 | work_flags |= WORK_STRUCT_INACTIVE; |
fe089f87 | 1724 | insert_work(pwq, work, &pwq->inactive_works, work_flags); |
8a2e8e5d | 1725 | } |
1e19ffc6 | 1726 | |
24acfb71 | 1727 | out: |
fe089f87 | 1728 | raw_spin_unlock(&pool->lock); |
24acfb71 | 1729 | rcu_read_unlock(); |
1da177e4 LT |
1730 | } |
1731 | ||
0fcb78c2 | 1732 | /** |
c1a220e7 ZR |
1733 | * queue_work_on - queue work on specific cpu |
1734 | * @cpu: CPU number to execute work on | |
0fcb78c2 REB |
1735 | * @wq: workqueue to use |
1736 | * @work: work to queue | |
1737 | * | |
c1a220e7 | 1738 | * We queue the work to a specific CPU, the caller must ensure it |
443378f0 PM |
1739 | * can't go away. Callers that fail to ensure that the specified |
1740 | * CPU cannot go away will execute on a randomly chosen CPU. | |
854f5cc5 PM |
1741 | * But note well that callers specifying a CPU that never has been |
1742 | * online will get a splat. | |
d185af30 YB |
1743 | * |
1744 | * Return: %false if @work was already on a queue, %true otherwise. | |
1da177e4 | 1745 | */ |
d4283e93 TH |
1746 | bool queue_work_on(int cpu, struct workqueue_struct *wq, |
1747 | struct work_struct *work) | |
1da177e4 | 1748 | { |
d4283e93 | 1749 | bool ret = false; |
8930caba | 1750 | unsigned long flags; |
ef1ca236 | 1751 | |
8930caba | 1752 | local_irq_save(flags); |
c1a220e7 | 1753 | |
22df02bb | 1754 | if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) { |
4690c4ab | 1755 | __queue_work(cpu, wq, work); |
d4283e93 | 1756 | ret = true; |
c1a220e7 | 1757 | } |
ef1ca236 | 1758 | |
8930caba | 1759 | local_irq_restore(flags); |
1da177e4 LT |
1760 | return ret; |
1761 | } | |
ad7b1f84 | 1762 | EXPORT_SYMBOL(queue_work_on); |
1da177e4 | 1763 | |
8204e0c1 | 1764 | /** |
fef59c9c | 1765 | * select_numa_node_cpu - Select a CPU based on NUMA node |
8204e0c1 AD |
1766 | * @node: NUMA node ID that we want to select a CPU from |
1767 | * | |
1768 | * This function will attempt to find a "random" cpu available on a given | |
1769 | * node. If there are no CPUs available on the given node it will return | |
1770 | * WORK_CPU_UNBOUND indicating that we should just schedule to any | |
1771 | * available CPU if we need to schedule this work. | |
1772 | */ | |
fef59c9c | 1773 | static int select_numa_node_cpu(int node) |
8204e0c1 AD |
1774 | { |
1775 | int cpu; | |
1776 | ||
1777 | /* No point in doing this if NUMA isn't enabled for workqueues */ | |
fef59c9c | 1778 | if (!wq_pod_enabled) |
8204e0c1 AD |
1779 | return WORK_CPU_UNBOUND; |
1780 | ||
1781 | /* Delay binding to CPU if node is not valid or online */ | |
1782 | if (node < 0 || node >= MAX_NUMNODES || !node_online(node)) | |
1783 | return WORK_CPU_UNBOUND; | |
1784 | ||
1785 | /* Use local node/cpu if we are already there */ | |
1786 | cpu = raw_smp_processor_id(); | |
1787 | if (node == cpu_to_node(cpu)) | |
1788 | return cpu; | |
1789 | ||
1790 | /* Use "random" otherwise know as "first" online CPU of node */ | |
1791 | cpu = cpumask_any_and(cpumask_of_node(node), cpu_online_mask); | |
1792 | ||
1793 | /* If CPU is valid return that, otherwise just defer */ | |
1794 | return cpu < nr_cpu_ids ? cpu : WORK_CPU_UNBOUND; | |
1795 | } | |
1796 | ||
1797 | /** | |
1798 | * queue_work_node - queue work on a "random" cpu for a given NUMA node | |
1799 | * @node: NUMA node that we are targeting the work for | |
1800 | * @wq: workqueue to use | |
1801 | * @work: work to queue | |
1802 | * | |
1803 | * We queue the work to a "random" CPU within a given NUMA node. The basic | |
1804 | * idea here is to provide a way to somehow associate work with a given | |
1805 | * NUMA node. | |
1806 | * | |
1807 | * This function will only make a best effort attempt at getting this onto | |
1808 | * the right NUMA node. If no node is requested or the requested node is | |
1809 | * offline then we just fall back to standard queue_work behavior. | |
1810 | * | |
1811 | * Currently the "random" CPU ends up being the first available CPU in the | |
1812 | * intersection of cpu_online_mask and the cpumask of the node, unless we | |
1813 | * are running on the node. In that case we just use the current CPU. | |
1814 | * | |
1815 | * Return: %false if @work was already on a queue, %true otherwise. | |
1816 | */ | |
1817 | bool queue_work_node(int node, struct workqueue_struct *wq, | |
1818 | struct work_struct *work) | |
1819 | { | |
1820 | unsigned long flags; | |
1821 | bool ret = false; | |
1822 | ||
1823 | /* | |
1824 | * This current implementation is specific to unbound workqueues. | |
1825 | * Specifically we only return the first available CPU for a given | |
1826 | * node instead of cycling through individual CPUs within the node. | |
1827 | * | |
1828 | * If this is used with a per-cpu workqueue then the logic in | |
1829 | * workqueue_select_cpu_near would need to be updated to allow for | |
1830 | * some round robin type logic. | |
1831 | */ | |
1832 | WARN_ON_ONCE(!(wq->flags & WQ_UNBOUND)); | |
1833 | ||
1834 | local_irq_save(flags); | |
1835 | ||
1836 | if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) { | |
fef59c9c | 1837 | int cpu = select_numa_node_cpu(node); |
8204e0c1 AD |
1838 | |
1839 | __queue_work(cpu, wq, work); | |
1840 | ret = true; | |
1841 | } | |
1842 | ||
1843 | local_irq_restore(flags); | |
1844 | return ret; | |
1845 | } | |
1846 | EXPORT_SYMBOL_GPL(queue_work_node); | |
1847 | ||
8c20feb6 | 1848 | void delayed_work_timer_fn(struct timer_list *t) |
1da177e4 | 1849 | { |
8c20feb6 | 1850 | struct delayed_work *dwork = from_timer(dwork, t, timer); |
1da177e4 | 1851 | |
e0aecdd8 | 1852 | /* should have been called from irqsafe timer with irq already off */ |
60c057bc | 1853 | __queue_work(dwork->cpu, dwork->wq, &dwork->work); |
1da177e4 | 1854 | } |
1438ade5 | 1855 | EXPORT_SYMBOL(delayed_work_timer_fn); |
1da177e4 | 1856 | |
7beb2edf TH |
1857 | static void __queue_delayed_work(int cpu, struct workqueue_struct *wq, |
1858 | struct delayed_work *dwork, unsigned long delay) | |
1da177e4 | 1859 | { |
7beb2edf TH |
1860 | struct timer_list *timer = &dwork->timer; |
1861 | struct work_struct *work = &dwork->work; | |
7beb2edf | 1862 | |
637fdbae | 1863 | WARN_ON_ONCE(!wq); |
4b243563 | 1864 | WARN_ON_ONCE(timer->function != delayed_work_timer_fn); |
fc4b514f TH |
1865 | WARN_ON_ONCE(timer_pending(timer)); |
1866 | WARN_ON_ONCE(!list_empty(&work->entry)); | |
7beb2edf | 1867 | |
8852aac2 TH |
1868 | /* |
1869 | * If @delay is 0, queue @dwork->work immediately. This is for | |
1870 | * both optimization and correctness. The earliest @timer can | |
1871 | * expire is on the closest next tick and delayed_work users depend | |
1872 | * on that there's no such delay when @delay is 0. | |
1873 | */ | |
1874 | if (!delay) { | |
1875 | __queue_work(cpu, wq, &dwork->work); | |
1876 | return; | |
1877 | } | |
1878 | ||
60c057bc | 1879 | dwork->wq = wq; |
1265057f | 1880 | dwork->cpu = cpu; |
7beb2edf TH |
1881 | timer->expires = jiffies + delay; |
1882 | ||
041bd12e TH |
1883 | if (unlikely(cpu != WORK_CPU_UNBOUND)) |
1884 | add_timer_on(timer, cpu); | |
1885 | else | |
1886 | add_timer(timer); | |
1da177e4 LT |
1887 | } |
1888 | ||
0fcb78c2 REB |
1889 | /** |
1890 | * queue_delayed_work_on - queue work on specific CPU after delay | |
1891 | * @cpu: CPU number to execute work on | |
1892 | * @wq: workqueue to use | |
af9997e4 | 1893 | * @dwork: work to queue |
0fcb78c2 REB |
1894 | * @delay: number of jiffies to wait before queueing |
1895 | * | |
d185af30 | 1896 | * Return: %false if @work was already on a queue, %true otherwise. If |
715f1300 TH |
1897 | * @delay is zero and @dwork is idle, it will be scheduled for immediate |
1898 | * execution. | |
0fcb78c2 | 1899 | */ |
d4283e93 TH |
1900 | bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq, |
1901 | struct delayed_work *dwork, unsigned long delay) | |
7a6bc1cd | 1902 | { |
52bad64d | 1903 | struct work_struct *work = &dwork->work; |
d4283e93 | 1904 | bool ret = false; |
8930caba | 1905 | unsigned long flags; |
7a6bc1cd | 1906 | |
8930caba TH |
1907 | /* read the comment in __queue_work() */ |
1908 | local_irq_save(flags); | |
7a6bc1cd | 1909 | |
22df02bb | 1910 | if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) { |
7beb2edf | 1911 | __queue_delayed_work(cpu, wq, dwork, delay); |
d4283e93 | 1912 | ret = true; |
7a6bc1cd | 1913 | } |
8a3e77cc | 1914 | |
8930caba | 1915 | local_irq_restore(flags); |
7a6bc1cd VP |
1916 | return ret; |
1917 | } | |
ad7b1f84 | 1918 | EXPORT_SYMBOL(queue_delayed_work_on); |
c7fc77f7 | 1919 | |
8376fe22 TH |
1920 | /** |
1921 | * mod_delayed_work_on - modify delay of or queue a delayed work on specific CPU | |
1922 | * @cpu: CPU number to execute work on | |
1923 | * @wq: workqueue to use | |
1924 | * @dwork: work to queue | |
1925 | * @delay: number of jiffies to wait before queueing | |
1926 | * | |
1927 | * If @dwork is idle, equivalent to queue_delayed_work_on(); otherwise, | |
1928 | * modify @dwork's timer so that it expires after @delay. If @delay is | |
1929 | * zero, @work is guaranteed to be scheduled immediately regardless of its | |
1930 | * current state. | |
1931 | * | |
d185af30 | 1932 | * Return: %false if @dwork was idle and queued, %true if @dwork was |
8376fe22 TH |
1933 | * pending and its timer was modified. |
1934 | * | |
e0aecdd8 | 1935 | * This function is safe to call from any context including IRQ handler. |
8376fe22 TH |
1936 | * See try_to_grab_pending() for details. |
1937 | */ | |
1938 | bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq, | |
1939 | struct delayed_work *dwork, unsigned long delay) | |
1940 | { | |
1941 | unsigned long flags; | |
1942 | int ret; | |
c7fc77f7 | 1943 | |
8376fe22 TH |
1944 | do { |
1945 | ret = try_to_grab_pending(&dwork->work, true, &flags); | |
1946 | } while (unlikely(ret == -EAGAIN)); | |
63bc0362 | 1947 | |
8376fe22 TH |
1948 | if (likely(ret >= 0)) { |
1949 | __queue_delayed_work(cpu, wq, dwork, delay); | |
1950 | local_irq_restore(flags); | |
7a6bc1cd | 1951 | } |
8376fe22 TH |
1952 | |
1953 | /* -ENOENT from try_to_grab_pending() becomes %true */ | |
7a6bc1cd VP |
1954 | return ret; |
1955 | } | |
8376fe22 TH |
1956 | EXPORT_SYMBOL_GPL(mod_delayed_work_on); |
1957 | ||
05f0fe6b TH |
1958 | static void rcu_work_rcufn(struct rcu_head *rcu) |
1959 | { | |
1960 | struct rcu_work *rwork = container_of(rcu, struct rcu_work, rcu); | |
1961 | ||
1962 | /* read the comment in __queue_work() */ | |
1963 | local_irq_disable(); | |
1964 | __queue_work(WORK_CPU_UNBOUND, rwork->wq, &rwork->work); | |
1965 | local_irq_enable(); | |
1966 | } | |
1967 | ||
1968 | /** | |
1969 | * queue_rcu_work - queue work after a RCU grace period | |
1970 | * @wq: workqueue to use | |
1971 | * @rwork: work to queue | |
1972 | * | |
1973 | * Return: %false if @rwork was already pending, %true otherwise. Note | |
1974 | * that a full RCU grace period is guaranteed only after a %true return. | |
bf393fd4 | 1975 | * While @rwork is guaranteed to be executed after a %false return, the |
05f0fe6b TH |
1976 | * execution may happen before a full RCU grace period has passed. |
1977 | */ | |
1978 | bool queue_rcu_work(struct workqueue_struct *wq, struct rcu_work *rwork) | |
1979 | { | |
1980 | struct work_struct *work = &rwork->work; | |
1981 | ||
1982 | if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) { | |
1983 | rwork->wq = wq; | |
a7e30c0e | 1984 | call_rcu_hurry(&rwork->rcu, rcu_work_rcufn); |
05f0fe6b TH |
1985 | return true; |
1986 | } | |
1987 | ||
1988 | return false; | |
1989 | } | |
1990 | EXPORT_SYMBOL(queue_rcu_work); | |
1991 | ||
f7537df5 | 1992 | static struct worker *alloc_worker(int node) |
c34056a3 TH |
1993 | { |
1994 | struct worker *worker; | |
1995 | ||
f7537df5 | 1996 | worker = kzalloc_node(sizeof(*worker), GFP_KERNEL, node); |
c8e55f36 TH |
1997 | if (worker) { |
1998 | INIT_LIST_HEAD(&worker->entry); | |
affee4b2 | 1999 | INIT_LIST_HEAD(&worker->scheduled); |
da028469 | 2000 | INIT_LIST_HEAD(&worker->node); |
e22bee78 TH |
2001 | /* on creation a worker is in !idle && prep state */ |
2002 | worker->flags = WORKER_PREP; | |
c8e55f36 | 2003 | } |
c34056a3 TH |
2004 | return worker; |
2005 | } | |
2006 | ||
4736cbf7 LJ |
2007 | /** |
2008 | * worker_attach_to_pool() - attach a worker to a pool | |
2009 | * @worker: worker to be attached | |
2010 | * @pool: the target pool | |
2011 | * | |
2012 | * Attach @worker to @pool. Once attached, the %WORKER_UNBOUND flag and | |
2013 | * cpu-binding of @worker are kept coordinated with the pool across | |
2014 | * cpu-[un]hotplugs. | |
2015 | */ | |
2016 | static void worker_attach_to_pool(struct worker *worker, | |
2017 | struct worker_pool *pool) | |
2018 | { | |
1258fae7 | 2019 | mutex_lock(&wq_pool_attach_mutex); |
4736cbf7 | 2020 | |
4736cbf7 | 2021 | /* |
1258fae7 TH |
2022 | * The wq_pool_attach_mutex ensures %POOL_DISASSOCIATED remains |
2023 | * stable across this function. See the comments above the flag | |
2024 | * definition for details. | |
4736cbf7 LJ |
2025 | */ |
2026 | if (pool->flags & POOL_DISASSOCIATED) | |
2027 | worker->flags |= WORKER_UNBOUND; | |
5c25b5ff PZ |
2028 | else |
2029 | kthread_set_per_cpu(worker->task, pool->cpu); | |
4736cbf7 | 2030 | |
640f17c8 PZ |
2031 | if (worker->rescue_wq) |
2032 | set_cpus_allowed_ptr(worker->task, pool->attrs->cpumask); | |
2033 | ||
4736cbf7 | 2034 | list_add_tail(&worker->node, &pool->workers); |
a2d812a2 | 2035 | worker->pool = pool; |
4736cbf7 | 2036 | |
1258fae7 | 2037 | mutex_unlock(&wq_pool_attach_mutex); |
4736cbf7 LJ |
2038 | } |
2039 | ||
60f5a4bc LJ |
2040 | /** |
2041 | * worker_detach_from_pool() - detach a worker from its pool | |
2042 | * @worker: worker which is attached to its pool | |
60f5a4bc | 2043 | * |
4736cbf7 LJ |
2044 | * Undo the attaching which had been done in worker_attach_to_pool(). The |
2045 | * caller worker shouldn't access to the pool after detached except it has | |
2046 | * other reference to the pool. | |
60f5a4bc | 2047 | */ |
a2d812a2 | 2048 | static void worker_detach_from_pool(struct worker *worker) |
60f5a4bc | 2049 | { |
a2d812a2 | 2050 | struct worker_pool *pool = worker->pool; |
60f5a4bc LJ |
2051 | struct completion *detach_completion = NULL; |
2052 | ||
1258fae7 | 2053 | mutex_lock(&wq_pool_attach_mutex); |
a2d812a2 | 2054 | |
5c25b5ff | 2055 | kthread_set_per_cpu(worker->task, -1); |
da028469 | 2056 | list_del(&worker->node); |
a2d812a2 TH |
2057 | worker->pool = NULL; |
2058 | ||
e02b9312 | 2059 | if (list_empty(&pool->workers) && list_empty(&pool->dying_workers)) |
60f5a4bc | 2060 | detach_completion = pool->detach_completion; |
1258fae7 | 2061 | mutex_unlock(&wq_pool_attach_mutex); |
60f5a4bc | 2062 | |
b62c0751 LJ |
2063 | /* clear leftover flags without pool->lock after it is detached */ |
2064 | worker->flags &= ~(WORKER_UNBOUND | WORKER_REBOUND); | |
2065 | ||
60f5a4bc LJ |
2066 | if (detach_completion) |
2067 | complete(detach_completion); | |
2068 | } | |
2069 | ||
c34056a3 TH |
2070 | /** |
2071 | * create_worker - create a new workqueue worker | |
63d95a91 | 2072 | * @pool: pool the new worker will belong to |
c34056a3 | 2073 | * |
051e1850 | 2074 | * Create and start a new worker which is attached to @pool. |
c34056a3 TH |
2075 | * |
2076 | * CONTEXT: | |
2077 | * Might sleep. Does GFP_KERNEL allocations. | |
2078 | * | |
d185af30 | 2079 | * Return: |
c34056a3 TH |
2080 | * Pointer to the newly created worker. |
2081 | */ | |
bc2ae0f5 | 2082 | static struct worker *create_worker(struct worker_pool *pool) |
c34056a3 | 2083 | { |
e441b56f ZL |
2084 | struct worker *worker; |
2085 | int id; | |
e3c916a4 | 2086 | char id_buf[16]; |
c34056a3 | 2087 | |
7cda9aae | 2088 | /* ID is needed to determine kthread name */ |
e441b56f | 2089 | id = ida_alloc(&pool->worker_ida, GFP_KERNEL); |
3f0ea0b8 PM |
2090 | if (id < 0) { |
2091 | pr_err_once("workqueue: Failed to allocate a worker ID: %pe\n", | |
2092 | ERR_PTR(id)); | |
e441b56f | 2093 | return NULL; |
3f0ea0b8 | 2094 | } |
c34056a3 | 2095 | |
f7537df5 | 2096 | worker = alloc_worker(pool->node); |
3f0ea0b8 PM |
2097 | if (!worker) { |
2098 | pr_err_once("workqueue: Failed to allocate a worker\n"); | |
c34056a3 | 2099 | goto fail; |
3f0ea0b8 | 2100 | } |
c34056a3 | 2101 | |
c34056a3 TH |
2102 | worker->id = id; |
2103 | ||
29c91e99 | 2104 | if (pool->cpu >= 0) |
e3c916a4 TH |
2105 | snprintf(id_buf, sizeof(id_buf), "%d:%d%s", pool->cpu, id, |
2106 | pool->attrs->nice < 0 ? "H" : ""); | |
f3421797 | 2107 | else |
e3c916a4 TH |
2108 | snprintf(id_buf, sizeof(id_buf), "u%d:%d", pool->id, id); |
2109 | ||
f3f90ad4 | 2110 | worker->task = kthread_create_on_node(worker_thread, worker, pool->node, |
e3c916a4 | 2111 | "kworker/%s", id_buf); |
3f0ea0b8 | 2112 | if (IS_ERR(worker->task)) { |
60f54038 PM |
2113 | if (PTR_ERR(worker->task) == -EINTR) { |
2114 | pr_err("workqueue: Interrupted when creating a worker thread \"kworker/%s\"\n", | |
2115 | id_buf); | |
2116 | } else { | |
2117 | pr_err_once("workqueue: Failed to create a worker thread: %pe", | |
2118 | worker->task); | |
2119 | } | |
c34056a3 | 2120 | goto fail; |
3f0ea0b8 | 2121 | } |
c34056a3 | 2122 | |
91151228 | 2123 | set_user_nice(worker->task, pool->attrs->nice); |
25834c73 | 2124 | kthread_bind_mask(worker->task, pool->attrs->cpumask); |
91151228 | 2125 | |
da028469 | 2126 | /* successful, attach the worker to the pool */ |
4736cbf7 | 2127 | worker_attach_to_pool(worker, pool); |
822d8405 | 2128 | |
051e1850 | 2129 | /* start the newly created worker */ |
a9b8a985 | 2130 | raw_spin_lock_irq(&pool->lock); |
051e1850 LJ |
2131 | worker->pool->nr_workers++; |
2132 | worker_enter_idle(worker); | |
2133 | wake_up_process(worker->task); | |
a9b8a985 | 2134 | raw_spin_unlock_irq(&pool->lock); |
051e1850 | 2135 | |
c34056a3 | 2136 | return worker; |
822d8405 | 2137 | |
c34056a3 | 2138 | fail: |
e441b56f | 2139 | ida_free(&pool->worker_ida, id); |
c34056a3 TH |
2140 | kfree(worker); |
2141 | return NULL; | |
2142 | } | |
2143 | ||
793777bc VS |
2144 | static void unbind_worker(struct worker *worker) |
2145 | { | |
2146 | lockdep_assert_held(&wq_pool_attach_mutex); | |
2147 | ||
2148 | kthread_set_per_cpu(worker->task, -1); | |
2149 | if (cpumask_intersects(wq_unbound_cpumask, cpu_active_mask)) | |
2150 | WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task, wq_unbound_cpumask) < 0); | |
2151 | else | |
2152 | WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task, cpu_possible_mask) < 0); | |
2153 | } | |
2154 | ||
e02b9312 VS |
2155 | static void wake_dying_workers(struct list_head *cull_list) |
2156 | { | |
2157 | struct worker *worker, *tmp; | |
2158 | ||
2159 | list_for_each_entry_safe(worker, tmp, cull_list, entry) { | |
2160 | list_del_init(&worker->entry); | |
2161 | unbind_worker(worker); | |
2162 | /* | |
2163 | * If the worker was somehow already running, then it had to be | |
2164 | * in pool->idle_list when set_worker_dying() happened or we | |
2165 | * wouldn't have gotten here. | |
2166 | * | |
2167 | * Thus, the worker must either have observed the WORKER_DIE | |
2168 | * flag, or have set its state to TASK_IDLE. Either way, the | |
2169 | * below will be observed by the worker and is safe to do | |
2170 | * outside of pool->lock. | |
2171 | */ | |
2172 | wake_up_process(worker->task); | |
2173 | } | |
2174 | } | |
2175 | ||
c34056a3 | 2176 | /** |
e02b9312 | 2177 | * set_worker_dying - Tag a worker for destruction |
c34056a3 | 2178 | * @worker: worker to be destroyed |
e02b9312 | 2179 | * @list: transfer worker away from its pool->idle_list and into list |
c34056a3 | 2180 | * |
e02b9312 VS |
2181 | * Tag @worker for destruction and adjust @pool stats accordingly. The worker |
2182 | * should be idle. | |
c8e55f36 TH |
2183 | * |
2184 | * CONTEXT: | |
a9b8a985 | 2185 | * raw_spin_lock_irq(pool->lock). |
c34056a3 | 2186 | */ |
e02b9312 | 2187 | static void set_worker_dying(struct worker *worker, struct list_head *list) |
c34056a3 | 2188 | { |
bd7bdd43 | 2189 | struct worker_pool *pool = worker->pool; |
c34056a3 | 2190 | |
cd549687 | 2191 | lockdep_assert_held(&pool->lock); |
e02b9312 | 2192 | lockdep_assert_held(&wq_pool_attach_mutex); |
cd549687 | 2193 | |
c34056a3 | 2194 | /* sanity check frenzy */ |
6183c009 | 2195 | if (WARN_ON(worker->current_work) || |
73eb7fe7 LJ |
2196 | WARN_ON(!list_empty(&worker->scheduled)) || |
2197 | WARN_ON(!(worker->flags & WORKER_IDLE))) | |
6183c009 | 2198 | return; |
c34056a3 | 2199 | |
73eb7fe7 LJ |
2200 | pool->nr_workers--; |
2201 | pool->nr_idle--; | |
5bdfff96 | 2202 | |
cb444766 | 2203 | worker->flags |= WORKER_DIE; |
e02b9312 VS |
2204 | |
2205 | list_move(&worker->entry, list); | |
2206 | list_move(&worker->node, &pool->dying_workers); | |
c34056a3 TH |
2207 | } |
2208 | ||
3f959aa3 VS |
2209 | /** |
2210 | * idle_worker_timeout - check if some idle workers can now be deleted. | |
2211 | * @t: The pool's idle_timer that just expired | |
2212 | * | |
2213 | * The timer is armed in worker_enter_idle(). Note that it isn't disarmed in | |
2214 | * worker_leave_idle(), as a worker flicking between idle and active while its | |
2215 | * pool is at the too_many_workers() tipping point would cause too much timer | |
2216 | * housekeeping overhead. Since IDLE_WORKER_TIMEOUT is long enough, we just let | |
2217 | * it expire and re-evaluate things from there. | |
2218 | */ | |
32a6c723 | 2219 | static void idle_worker_timeout(struct timer_list *t) |
e22bee78 | 2220 | { |
32a6c723 | 2221 | struct worker_pool *pool = from_timer(pool, t, idle_timer); |
3f959aa3 VS |
2222 | bool do_cull = false; |
2223 | ||
2224 | if (work_pending(&pool->idle_cull_work)) | |
2225 | return; | |
e22bee78 | 2226 | |
a9b8a985 | 2227 | raw_spin_lock_irq(&pool->lock); |
e22bee78 | 2228 | |
3f959aa3 | 2229 | if (too_many_workers(pool)) { |
e22bee78 TH |
2230 | struct worker *worker; |
2231 | unsigned long expires; | |
2232 | ||
2233 | /* idle_list is kept in LIFO order, check the last one */ | |
3f959aa3 VS |
2234 | worker = list_entry(pool->idle_list.prev, struct worker, entry); |
2235 | expires = worker->last_active + IDLE_WORKER_TIMEOUT; | |
2236 | do_cull = !time_before(jiffies, expires); | |
2237 | ||
2238 | if (!do_cull) | |
2239 | mod_timer(&pool->idle_timer, expires); | |
2240 | } | |
2241 | raw_spin_unlock_irq(&pool->lock); | |
2242 | ||
2243 | if (do_cull) | |
2244 | queue_work(system_unbound_wq, &pool->idle_cull_work); | |
2245 | } | |
2246 | ||
2247 | /** | |
2248 | * idle_cull_fn - cull workers that have been idle for too long. | |
2249 | * @work: the pool's work for handling these idle workers | |
2250 | * | |
2251 | * This goes through a pool's idle workers and gets rid of those that have been | |
2252 | * idle for at least IDLE_WORKER_TIMEOUT seconds. | |
e02b9312 VS |
2253 | * |
2254 | * We don't want to disturb isolated CPUs because of a pcpu kworker being | |
2255 | * culled, so this also resets worker affinity. This requires a sleepable | |
2256 | * context, hence the split between timer callback and work item. | |
3f959aa3 VS |
2257 | */ |
2258 | static void idle_cull_fn(struct work_struct *work) | |
2259 | { | |
2260 | struct worker_pool *pool = container_of(work, struct worker_pool, idle_cull_work); | |
9680540c | 2261 | LIST_HEAD(cull_list); |
3f959aa3 | 2262 | |
e02b9312 VS |
2263 | /* |
2264 | * Grabbing wq_pool_attach_mutex here ensures an already-running worker | |
2265 | * cannot proceed beyong worker_detach_from_pool() in its self-destruct | |
2266 | * path. This is required as a previously-preempted worker could run after | |
2267 | * set_worker_dying() has happened but before wake_dying_workers() did. | |
2268 | */ | |
2269 | mutex_lock(&wq_pool_attach_mutex); | |
3f959aa3 VS |
2270 | raw_spin_lock_irq(&pool->lock); |
2271 | ||
2272 | while (too_many_workers(pool)) { | |
2273 | struct worker *worker; | |
2274 | unsigned long expires; | |
2275 | ||
63d95a91 | 2276 | worker = list_entry(pool->idle_list.prev, struct worker, entry); |
e22bee78 TH |
2277 | expires = worker->last_active + IDLE_WORKER_TIMEOUT; |
2278 | ||
3347fc9f | 2279 | if (time_before(jiffies, expires)) { |
63d95a91 | 2280 | mod_timer(&pool->idle_timer, expires); |
3347fc9f | 2281 | break; |
d5abe669 | 2282 | } |
3347fc9f | 2283 | |
e02b9312 | 2284 | set_worker_dying(worker, &cull_list); |
e22bee78 TH |
2285 | } |
2286 | ||
a9b8a985 | 2287 | raw_spin_unlock_irq(&pool->lock); |
e02b9312 VS |
2288 | wake_dying_workers(&cull_list); |
2289 | mutex_unlock(&wq_pool_attach_mutex); | |
e22bee78 | 2290 | } |
d5abe669 | 2291 | |
493a1724 | 2292 | static void send_mayday(struct work_struct *work) |
e22bee78 | 2293 | { |
112202d9 TH |
2294 | struct pool_workqueue *pwq = get_work_pwq(work); |
2295 | struct workqueue_struct *wq = pwq->wq; | |
493a1724 | 2296 | |
2e109a28 | 2297 | lockdep_assert_held(&wq_mayday_lock); |
e22bee78 | 2298 | |
493008a8 | 2299 | if (!wq->rescuer) |
493a1724 | 2300 | return; |
e22bee78 TH |
2301 | |
2302 | /* mayday mayday mayday */ | |
493a1724 | 2303 | if (list_empty(&pwq->mayday_node)) { |
77668c8b LJ |
2304 | /* |
2305 | * If @pwq is for an unbound wq, its base ref may be put at | |
2306 | * any time due to an attribute change. Pin @pwq until the | |
2307 | * rescuer is done with it. | |
2308 | */ | |
2309 | get_pwq(pwq); | |
493a1724 | 2310 | list_add_tail(&pwq->mayday_node, &wq->maydays); |
e22bee78 | 2311 | wake_up_process(wq->rescuer->task); |
725e8ec5 | 2312 | pwq->stats[PWQ_STAT_MAYDAY]++; |
493a1724 | 2313 | } |
e22bee78 TH |
2314 | } |
2315 | ||
32a6c723 | 2316 | static void pool_mayday_timeout(struct timer_list *t) |
e22bee78 | 2317 | { |
32a6c723 | 2318 | struct worker_pool *pool = from_timer(pool, t, mayday_timer); |
e22bee78 TH |
2319 | struct work_struct *work; |
2320 | ||
a9b8a985 SAS |
2321 | raw_spin_lock_irq(&pool->lock); |
2322 | raw_spin_lock(&wq_mayday_lock); /* for wq->maydays */ | |
e22bee78 | 2323 | |
63d95a91 | 2324 | if (need_to_create_worker(pool)) { |
e22bee78 TH |
2325 | /* |
2326 | * We've been trying to create a new worker but | |
2327 | * haven't been successful. We might be hitting an | |
2328 | * allocation deadlock. Send distress signals to | |
2329 | * rescuers. | |
2330 | */ | |
63d95a91 | 2331 | list_for_each_entry(work, &pool->worklist, entry) |
e22bee78 | 2332 | send_mayday(work); |
1da177e4 | 2333 | } |
e22bee78 | 2334 | |
a9b8a985 SAS |
2335 | raw_spin_unlock(&wq_mayday_lock); |
2336 | raw_spin_unlock_irq(&pool->lock); | |
e22bee78 | 2337 | |
63d95a91 | 2338 | mod_timer(&pool->mayday_timer, jiffies + MAYDAY_INTERVAL); |
1da177e4 LT |
2339 | } |
2340 | ||
e22bee78 TH |
2341 | /** |
2342 | * maybe_create_worker - create a new worker if necessary | |
63d95a91 | 2343 | * @pool: pool to create a new worker for |
e22bee78 | 2344 | * |
63d95a91 | 2345 | * Create a new worker for @pool if necessary. @pool is guaranteed to |
e22bee78 TH |
2346 | * have at least one idle worker on return from this function. If |
2347 | * creating a new worker takes longer than MAYDAY_INTERVAL, mayday is | |
63d95a91 | 2348 | * sent to all rescuers with works scheduled on @pool to resolve |
e22bee78 TH |
2349 | * possible allocation deadlock. |
2350 | * | |
c5aa87bb TH |
2351 | * On return, need_to_create_worker() is guaranteed to be %false and |
2352 | * may_start_working() %true. | |
e22bee78 TH |
2353 | * |
2354 | * LOCKING: | |
a9b8a985 | 2355 | * raw_spin_lock_irq(pool->lock) which may be released and regrabbed |
e22bee78 TH |
2356 | * multiple times. Does GFP_KERNEL allocations. Called only from |
2357 | * manager. | |
e22bee78 | 2358 | */ |
29187a9e | 2359 | static void maybe_create_worker(struct worker_pool *pool) |
d565ed63 TH |
2360 | __releases(&pool->lock) |
2361 | __acquires(&pool->lock) | |
1da177e4 | 2362 | { |
e22bee78 | 2363 | restart: |
a9b8a985 | 2364 | raw_spin_unlock_irq(&pool->lock); |
9f9c2364 | 2365 | |
e22bee78 | 2366 | /* if we don't make progress in MAYDAY_INITIAL_TIMEOUT, call for help */ |
63d95a91 | 2367 | mod_timer(&pool->mayday_timer, jiffies + MAYDAY_INITIAL_TIMEOUT); |
e22bee78 TH |
2368 | |
2369 | while (true) { | |
051e1850 | 2370 | if (create_worker(pool) || !need_to_create_worker(pool)) |
e22bee78 | 2371 | break; |
1da177e4 | 2372 | |
e212f361 | 2373 | schedule_timeout_interruptible(CREATE_COOLDOWN); |
9f9c2364 | 2374 | |
63d95a91 | 2375 | if (!need_to_create_worker(pool)) |
e22bee78 TH |
2376 | break; |
2377 | } | |
2378 | ||
63d95a91 | 2379 | del_timer_sync(&pool->mayday_timer); |
a9b8a985 | 2380 | raw_spin_lock_irq(&pool->lock); |
051e1850 LJ |
2381 | /* |
2382 | * This is necessary even after a new worker was just successfully | |
2383 | * created as @pool->lock was dropped and the new worker might have | |
2384 | * already become busy. | |
2385 | */ | |
63d95a91 | 2386 | if (need_to_create_worker(pool)) |
e22bee78 | 2387 | goto restart; |
e22bee78 TH |
2388 | } |
2389 | ||
73f53c4a | 2390 | /** |
e22bee78 TH |
2391 | * manage_workers - manage worker pool |
2392 | * @worker: self | |
73f53c4a | 2393 | * |
706026c2 | 2394 | * Assume the manager role and manage the worker pool @worker belongs |
e22bee78 | 2395 | * to. At any given time, there can be only zero or one manager per |
706026c2 | 2396 | * pool. The exclusion is handled automatically by this function. |
e22bee78 TH |
2397 | * |
2398 | * The caller can safely start processing works on false return. On | |
2399 | * true return, it's guaranteed that need_to_create_worker() is false | |
2400 | * and may_start_working() is true. | |
73f53c4a TH |
2401 | * |
2402 | * CONTEXT: | |
a9b8a985 | 2403 | * raw_spin_lock_irq(pool->lock) which may be released and regrabbed |
e22bee78 TH |
2404 | * multiple times. Does GFP_KERNEL allocations. |
2405 | * | |
d185af30 | 2406 | * Return: |
29187a9e TH |
2407 | * %false if the pool doesn't need management and the caller can safely |
2408 | * start processing works, %true if management function was performed and | |
2409 | * the conditions that the caller verified before calling the function may | |
2410 | * no longer be true. | |
73f53c4a | 2411 | */ |
e22bee78 | 2412 | static bool manage_workers(struct worker *worker) |
73f53c4a | 2413 | { |
63d95a91 | 2414 | struct worker_pool *pool = worker->pool; |
73f53c4a | 2415 | |
692b4825 | 2416 | if (pool->flags & POOL_MANAGER_ACTIVE) |
29187a9e | 2417 | return false; |
692b4825 TH |
2418 | |
2419 | pool->flags |= POOL_MANAGER_ACTIVE; | |
2607d7a6 | 2420 | pool->manager = worker; |
1e19ffc6 | 2421 | |
29187a9e | 2422 | maybe_create_worker(pool); |
e22bee78 | 2423 | |
2607d7a6 | 2424 | pool->manager = NULL; |
692b4825 | 2425 | pool->flags &= ~POOL_MANAGER_ACTIVE; |
d8bb65ab | 2426 | rcuwait_wake_up(&manager_wait); |
29187a9e | 2427 | return true; |
73f53c4a TH |
2428 | } |
2429 | ||
a62428c0 TH |
2430 | /** |
2431 | * process_one_work - process single work | |
c34056a3 | 2432 | * @worker: self |
a62428c0 TH |
2433 | * @work: work to process |
2434 | * | |
2435 | * Process @work. This function contains all the logics necessary to | |
2436 | * process a single work including synchronization against and | |
2437 | * interaction with other workers on the same cpu, queueing and | |
2438 | * flushing. As long as context requirement is met, any worker can | |
2439 | * call this function to process a work. | |
2440 | * | |
2441 | * CONTEXT: | |
a9b8a985 | 2442 | * raw_spin_lock_irq(pool->lock) which is released and regrabbed. |
a62428c0 | 2443 | */ |
c34056a3 | 2444 | static void process_one_work(struct worker *worker, struct work_struct *work) |
d565ed63 TH |
2445 | __releases(&pool->lock) |
2446 | __acquires(&pool->lock) | |
a62428c0 | 2447 | { |
112202d9 | 2448 | struct pool_workqueue *pwq = get_work_pwq(work); |
bd7bdd43 | 2449 | struct worker_pool *pool = worker->pool; |
c4560c2c | 2450 | unsigned long work_data; |
7e11629d | 2451 | struct worker *collision; |
a62428c0 TH |
2452 | #ifdef CONFIG_LOCKDEP |
2453 | /* | |
2454 | * It is permissible to free the struct work_struct from | |
2455 | * inside the function that is called from it, this we need to | |
2456 | * take into account for lockdep too. To avoid bogus "held | |
2457 | * lock freed" warnings as well as problems when looking into | |
2458 | * work->lockdep_map, make a copy and use that here. | |
2459 | */ | |
4d82a1de PZ |
2460 | struct lockdep_map lockdep_map; |
2461 | ||
2462 | lockdep_copy_map(&lockdep_map, &work->lockdep_map); | |
a62428c0 | 2463 | #endif |
807407c0 | 2464 | /* ensure we're on the correct CPU */ |
85327af6 | 2465 | WARN_ON_ONCE(!(pool->flags & POOL_DISASSOCIATED) && |
ec22ca5e | 2466 | raw_smp_processor_id() != pool->cpu); |
25511a47 | 2467 | |
7e11629d TH |
2468 | /* |
2469 | * A single work shouldn't be executed concurrently by | |
2470 | * multiple workers on a single cpu. Check whether anyone is | |
2471 | * already processing the work. If so, defer the work to the | |
2472 | * currently executing one. | |
2473 | */ | |
c9e7cf27 | 2474 | collision = find_worker_executing_work(pool, work); |
7e11629d TH |
2475 | if (unlikely(collision)) { |
2476 | move_linked_works(work, &collision->scheduled, NULL); | |
2477 | return; | |
2478 | } | |
2479 | ||
8930caba | 2480 | /* claim and dequeue */ |
a62428c0 | 2481 | debug_work_deactivate(work); |
c9e7cf27 | 2482 | hash_add(pool->busy_hash, &worker->hentry, (unsigned long)work); |
c34056a3 | 2483 | worker->current_work = work; |
a2c1c57b | 2484 | worker->current_func = work->func; |
112202d9 | 2485 | worker->current_pwq = pwq; |
616db877 | 2486 | worker->current_at = worker->task->se.sum_exec_runtime; |
c4560c2c | 2487 | work_data = *work_data_bits(work); |
d812796e | 2488 | worker->current_color = get_work_color(work_data); |
7a22ad75 | 2489 | |
8bf89593 TH |
2490 | /* |
2491 | * Record wq name for cmdline and debug reporting, may get | |
2492 | * overridden through set_worker_desc(). | |
2493 | */ | |
2494 | strscpy(worker->desc, pwq->wq->name, WORKER_DESC_LEN); | |
2495 | ||
a62428c0 TH |
2496 | list_del_init(&work->entry); |
2497 | ||
fb0e7beb | 2498 | /* |
228f1d00 LJ |
2499 | * CPU intensive works don't participate in concurrency management. |
2500 | * They're the scheduler's responsibility. This takes @worker out | |
2501 | * of concurrency management and the next code block will chain | |
2502 | * execution of the pending work items. | |
fb0e7beb | 2503 | */ |
616db877 | 2504 | if (unlikely(pwq->wq->flags & WQ_CPU_INTENSIVE)) |
228f1d00 | 2505 | worker_set_flags(worker, WORKER_CPU_INTENSIVE); |
fb0e7beb | 2506 | |
974271c4 | 2507 | /* |
a489a03e LJ |
2508 | * Wake up another worker if necessary. The condition is always |
2509 | * false for normal per-cpu workers since nr_running would always | |
2510 | * be >= 1 at this point. This is used to chain execution of the | |
2511 | * pending work items for WORKER_NOT_RUNNING workers such as the | |
228f1d00 | 2512 | * UNBOUND and CPU_INTENSIVE ones. |
974271c4 | 2513 | */ |
a489a03e | 2514 | if (need_more_worker(pool)) |
63d95a91 | 2515 | wake_up_worker(pool); |
974271c4 | 2516 | |
8930caba | 2517 | /* |
7c3eed5c | 2518 | * Record the last pool and clear PENDING which should be the last |
d565ed63 | 2519 | * update to @work. Also, do this inside @pool->lock so that |
23657bb1 TH |
2520 | * PENDING and queued state changes happen together while IRQ is |
2521 | * disabled. | |
8930caba | 2522 | */ |
7c3eed5c | 2523 | set_work_pool_and_clear_pending(work, pool->id); |
a62428c0 | 2524 | |
a9b8a985 | 2525 | raw_spin_unlock_irq(&pool->lock); |
a62428c0 | 2526 | |
a1d14934 | 2527 | lock_map_acquire(&pwq->wq->lockdep_map); |
a62428c0 | 2528 | lock_map_acquire(&lockdep_map); |
e6f3faa7 | 2529 | /* |
f52be570 PZ |
2530 | * Strictly speaking we should mark the invariant state without holding |
2531 | * any locks, that is, before these two lock_map_acquire()'s. | |
e6f3faa7 PZ |
2532 | * |
2533 | * However, that would result in: | |
2534 | * | |
2535 | * A(W1) | |
2536 | * WFC(C) | |
2537 | * A(W1) | |
2538 | * C(C) | |
2539 | * | |
2540 | * Which would create W1->C->W1 dependencies, even though there is no | |
2541 | * actual deadlock possible. There are two solutions, using a | |
2542 | * read-recursive acquire on the work(queue) 'locks', but this will then | |
f52be570 | 2543 | * hit the lockdep limitation on recursive locks, or simply discard |
e6f3faa7 PZ |
2544 | * these locks. |
2545 | * | |
2546 | * AFAICT there is no possible deadlock scenario between the | |
2547 | * flush_work() and complete() primitives (except for single-threaded | |
2548 | * workqueues), so hiding them isn't a problem. | |
2549 | */ | |
f52be570 | 2550 | lockdep_invariant_state(true); |
725e8ec5 | 2551 | pwq->stats[PWQ_STAT_STARTED]++; |
e36c886a | 2552 | trace_workqueue_execute_start(work); |
a2c1c57b | 2553 | worker->current_func(work); |
e36c886a AV |
2554 | /* |
2555 | * While we must be careful to not use "work" after this, the trace | |
2556 | * point will only record its address. | |
2557 | */ | |
1c5da0ec | 2558 | trace_workqueue_execute_end(work, worker->current_func); |
725e8ec5 | 2559 | pwq->stats[PWQ_STAT_COMPLETED]++; |
a62428c0 | 2560 | lock_map_release(&lockdep_map); |
112202d9 | 2561 | lock_map_release(&pwq->wq->lockdep_map); |
a62428c0 TH |
2562 | |
2563 | if (unlikely(in_atomic() || lockdep_depth(current) > 0)) { | |
044c782c | 2564 | pr_err("BUG: workqueue leaked lock or atomic: %s/0x%08x/%d\n" |
d75f773c | 2565 | " last function: %ps\n", |
a2c1c57b TH |
2566 | current->comm, preempt_count(), task_pid_nr(current), |
2567 | worker->current_func); | |
a62428c0 TH |
2568 | debug_show_held_locks(current); |
2569 | dump_stack(); | |
2570 | } | |
2571 | ||
b22ce278 | 2572 | /* |
025f50f3 | 2573 | * The following prevents a kworker from hogging CPU on !PREEMPTION |
b22ce278 TH |
2574 | * kernels, where a requeueing work item waiting for something to |
2575 | * happen could deadlock with stop_machine as such work item could | |
2576 | * indefinitely requeue itself while all other CPUs are trapped in | |
789cbbec JL |
2577 | * stop_machine. At the same time, report a quiescent RCU state so |
2578 | * the same condition doesn't freeze RCU. | |
b22ce278 | 2579 | */ |
a7e6425e | 2580 | cond_resched(); |
b22ce278 | 2581 | |
a9b8a985 | 2582 | raw_spin_lock_irq(&pool->lock); |
a62428c0 | 2583 | |
616db877 TH |
2584 | /* |
2585 | * In addition to %WQ_CPU_INTENSIVE, @worker may also have been marked | |
2586 | * CPU intensive by wq_worker_tick() if @work hogged CPU longer than | |
2587 | * wq_cpu_intensive_thresh_us. Clear it. | |
2588 | */ | |
2589 | worker_clr_flags(worker, WORKER_CPU_INTENSIVE); | |
fb0e7beb | 2590 | |
1b69ac6b JW |
2591 | /* tag the worker for identification in schedule() */ |
2592 | worker->last_func = worker->current_func; | |
2593 | ||
a62428c0 | 2594 | /* we're done with it, release */ |
42f8570f | 2595 | hash_del(&worker->hentry); |
c34056a3 | 2596 | worker->current_work = NULL; |
a2c1c57b | 2597 | worker->current_func = NULL; |
112202d9 | 2598 | worker->current_pwq = NULL; |
d812796e | 2599 | worker->current_color = INT_MAX; |
c4560c2c | 2600 | pwq_dec_nr_in_flight(pwq, work_data); |
a62428c0 TH |
2601 | } |
2602 | ||
affee4b2 TH |
2603 | /** |
2604 | * process_scheduled_works - process scheduled works | |
2605 | * @worker: self | |
2606 | * | |
2607 | * Process all scheduled works. Please note that the scheduled list | |
2608 | * may change while processing a work, so this function repeatedly | |
2609 | * fetches a work from the top and executes it. | |
2610 | * | |
2611 | * CONTEXT: | |
a9b8a985 | 2612 | * raw_spin_lock_irq(pool->lock) which may be released and regrabbed |
affee4b2 TH |
2613 | * multiple times. |
2614 | */ | |
2615 | static void process_scheduled_works(struct worker *worker) | |
1da177e4 | 2616 | { |
c0ab017d TH |
2617 | struct work_struct *work; |
2618 | bool first = true; | |
2619 | ||
2620 | while ((work = list_first_entry_or_null(&worker->scheduled, | |
2621 | struct work_struct, entry))) { | |
2622 | if (first) { | |
2623 | worker->pool->watchdog_ts = jiffies; | |
2624 | first = false; | |
2625 | } | |
c34056a3 | 2626 | process_one_work(worker, work); |
1da177e4 | 2627 | } |
1da177e4 LT |
2628 | } |
2629 | ||
197f6acc TH |
2630 | static void set_pf_worker(bool val) |
2631 | { | |
2632 | mutex_lock(&wq_pool_attach_mutex); | |
2633 | if (val) | |
2634 | current->flags |= PF_WQ_WORKER; | |
2635 | else | |
2636 | current->flags &= ~PF_WQ_WORKER; | |
2637 | mutex_unlock(&wq_pool_attach_mutex); | |
2638 | } | |
2639 | ||
4690c4ab TH |
2640 | /** |
2641 | * worker_thread - the worker thread function | |
c34056a3 | 2642 | * @__worker: self |
4690c4ab | 2643 | * |
c5aa87bb TH |
2644 | * The worker thread function. All workers belong to a worker_pool - |
2645 | * either a per-cpu one or dynamic unbound one. These workers process all | |
2646 | * work items regardless of their specific target workqueue. The only | |
2647 | * exception is work items which belong to workqueues with a rescuer which | |
2648 | * will be explained in rescuer_thread(). | |
d185af30 YB |
2649 | * |
2650 | * Return: 0 | |
4690c4ab | 2651 | */ |
c34056a3 | 2652 | static int worker_thread(void *__worker) |
1da177e4 | 2653 | { |
c34056a3 | 2654 | struct worker *worker = __worker; |
bd7bdd43 | 2655 | struct worker_pool *pool = worker->pool; |
1da177e4 | 2656 | |
e22bee78 | 2657 | /* tell the scheduler that this is a workqueue worker */ |
197f6acc | 2658 | set_pf_worker(true); |
c8e55f36 | 2659 | woke_up: |
a9b8a985 | 2660 | raw_spin_lock_irq(&pool->lock); |
1da177e4 | 2661 | |
a9ab775b TH |
2662 | /* am I supposed to die? */ |
2663 | if (unlikely(worker->flags & WORKER_DIE)) { | |
a9b8a985 | 2664 | raw_spin_unlock_irq(&pool->lock); |
197f6acc | 2665 | set_pf_worker(false); |
60f5a4bc LJ |
2666 | |
2667 | set_task_comm(worker->task, "kworker/dying"); | |
e441b56f | 2668 | ida_free(&pool->worker_ida, worker->id); |
a2d812a2 | 2669 | worker_detach_from_pool(worker); |
e02b9312 | 2670 | WARN_ON_ONCE(!list_empty(&worker->entry)); |
60f5a4bc | 2671 | kfree(worker); |
a9ab775b | 2672 | return 0; |
c8e55f36 | 2673 | } |
affee4b2 | 2674 | |
c8e55f36 | 2675 | worker_leave_idle(worker); |
db7bccf4 | 2676 | recheck: |
e22bee78 | 2677 | /* no more worker necessary? */ |
63d95a91 | 2678 | if (!need_more_worker(pool)) |
e22bee78 TH |
2679 | goto sleep; |
2680 | ||
2681 | /* do we need to manage? */ | |
63d95a91 | 2682 | if (unlikely(!may_start_working(pool)) && manage_workers(worker)) |
e22bee78 TH |
2683 | goto recheck; |
2684 | ||
c8e55f36 TH |
2685 | /* |
2686 | * ->scheduled list can only be filled while a worker is | |
2687 | * preparing to process a work or actually processing it. | |
2688 | * Make sure nobody diddled with it while I was sleeping. | |
2689 | */ | |
6183c009 | 2690 | WARN_ON_ONCE(!list_empty(&worker->scheduled)); |
c8e55f36 | 2691 | |
e22bee78 | 2692 | /* |
a9ab775b TH |
2693 | * Finish PREP stage. We're guaranteed to have at least one idle |
2694 | * worker or that someone else has already assumed the manager | |
2695 | * role. This is where @worker starts participating in concurrency | |
2696 | * management if applicable and concurrency management is restored | |
2697 | * after being rebound. See rebind_workers() for details. | |
e22bee78 | 2698 | */ |
a9ab775b | 2699 | worker_clr_flags(worker, WORKER_PREP | WORKER_REBOUND); |
e22bee78 TH |
2700 | |
2701 | do { | |
c8e55f36 | 2702 | struct work_struct *work = |
bd7bdd43 | 2703 | list_first_entry(&pool->worklist, |
c8e55f36 TH |
2704 | struct work_struct, entry); |
2705 | ||
c0ab017d TH |
2706 | move_linked_works(work, &worker->scheduled, NULL); |
2707 | process_scheduled_works(worker); | |
63d95a91 | 2708 | } while (keep_working(pool)); |
e22bee78 | 2709 | |
228f1d00 | 2710 | worker_set_flags(worker, WORKER_PREP); |
d313dd85 | 2711 | sleep: |
c8e55f36 | 2712 | /* |
d565ed63 TH |
2713 | * pool->lock is held and there's no work to process and no need to |
2714 | * manage, sleep. Workers are woken up only while holding | |
2715 | * pool->lock or from local cpu, so setting the current state | |
2716 | * before releasing pool->lock is enough to prevent losing any | |
2717 | * event. | |
c8e55f36 TH |
2718 | */ |
2719 | worker_enter_idle(worker); | |
c5a94a61 | 2720 | __set_current_state(TASK_IDLE); |
a9b8a985 | 2721 | raw_spin_unlock_irq(&pool->lock); |
c8e55f36 TH |
2722 | schedule(); |
2723 | goto woke_up; | |
1da177e4 LT |
2724 | } |
2725 | ||
e22bee78 TH |
2726 | /** |
2727 | * rescuer_thread - the rescuer thread function | |
111c225a | 2728 | * @__rescuer: self |
e22bee78 TH |
2729 | * |
2730 | * Workqueue rescuer thread function. There's one rescuer for each | |
493008a8 | 2731 | * workqueue which has WQ_MEM_RECLAIM set. |
e22bee78 | 2732 | * |
706026c2 | 2733 | * Regular work processing on a pool may block trying to create a new |
e22bee78 TH |
2734 | * worker which uses GFP_KERNEL allocation which has slight chance of |
2735 | * developing into deadlock if some works currently on the same queue | |
2736 | * need to be processed to satisfy the GFP_KERNEL allocation. This is | |
2737 | * the problem rescuer solves. | |
2738 | * | |
706026c2 TH |
2739 | * When such condition is possible, the pool summons rescuers of all |
2740 | * workqueues which have works queued on the pool and let them process | |
e22bee78 TH |
2741 | * those works so that forward progress can be guaranteed. |
2742 | * | |
2743 | * This should happen rarely. | |
d185af30 YB |
2744 | * |
2745 | * Return: 0 | |
e22bee78 | 2746 | */ |
111c225a | 2747 | static int rescuer_thread(void *__rescuer) |
e22bee78 | 2748 | { |
111c225a TH |
2749 | struct worker *rescuer = __rescuer; |
2750 | struct workqueue_struct *wq = rescuer->rescue_wq; | |
e22bee78 | 2751 | struct list_head *scheduled = &rescuer->scheduled; |
4d595b86 | 2752 | bool should_stop; |
e22bee78 TH |
2753 | |
2754 | set_user_nice(current, RESCUER_NICE_LEVEL); | |
111c225a TH |
2755 | |
2756 | /* | |
2757 | * Mark rescuer as worker too. As WORKER_PREP is never cleared, it | |
2758 | * doesn't participate in concurrency management. | |
2759 | */ | |
197f6acc | 2760 | set_pf_worker(true); |
e22bee78 | 2761 | repeat: |
c5a94a61 | 2762 | set_current_state(TASK_IDLE); |
e22bee78 | 2763 | |
4d595b86 LJ |
2764 | /* |
2765 | * By the time the rescuer is requested to stop, the workqueue | |
2766 | * shouldn't have any work pending, but @wq->maydays may still have | |
2767 | * pwq(s) queued. This can happen by non-rescuer workers consuming | |
2768 | * all the work items before the rescuer got to them. Go through | |
2769 | * @wq->maydays processing before acting on should_stop so that the | |
2770 | * list is always empty on exit. | |
2771 | */ | |
2772 | should_stop = kthread_should_stop(); | |
e22bee78 | 2773 | |
493a1724 | 2774 | /* see whether any pwq is asking for help */ |
a9b8a985 | 2775 | raw_spin_lock_irq(&wq_mayday_lock); |
493a1724 TH |
2776 | |
2777 | while (!list_empty(&wq->maydays)) { | |
2778 | struct pool_workqueue *pwq = list_first_entry(&wq->maydays, | |
2779 | struct pool_workqueue, mayday_node); | |
112202d9 | 2780 | struct worker_pool *pool = pwq->pool; |
e22bee78 TH |
2781 | struct work_struct *work, *n; |
2782 | ||
2783 | __set_current_state(TASK_RUNNING); | |
493a1724 TH |
2784 | list_del_init(&pwq->mayday_node); |
2785 | ||
a9b8a985 | 2786 | raw_spin_unlock_irq(&wq_mayday_lock); |
e22bee78 | 2787 | |
51697d39 LJ |
2788 | worker_attach_to_pool(rescuer, pool); |
2789 | ||
a9b8a985 | 2790 | raw_spin_lock_irq(&pool->lock); |
e22bee78 TH |
2791 | |
2792 | /* | |
2793 | * Slurp in all works issued via this workqueue and | |
2794 | * process'em. | |
2795 | */ | |
0479c8c5 | 2796 | WARN_ON_ONCE(!list_empty(scheduled)); |
82607adc TH |
2797 | list_for_each_entry_safe(work, n, &pool->worklist, entry) { |
2798 | if (get_work_pwq(work) == pwq) { | |
e22bee78 | 2799 | move_linked_works(work, scheduled, &n); |
725e8ec5 | 2800 | pwq->stats[PWQ_STAT_RESCUED]++; |
82607adc | 2801 | } |
82607adc | 2802 | } |
e22bee78 | 2803 | |
008847f6 N |
2804 | if (!list_empty(scheduled)) { |
2805 | process_scheduled_works(rescuer); | |
2806 | ||
2807 | /* | |
2808 | * The above execution of rescued work items could | |
2809 | * have created more to rescue through | |
f97a4a1a | 2810 | * pwq_activate_first_inactive() or chained |
008847f6 N |
2811 | * queueing. Let's put @pwq back on mayday list so |
2812 | * that such back-to-back work items, which may be | |
2813 | * being used to relieve memory pressure, don't | |
2814 | * incur MAYDAY_INTERVAL delay inbetween. | |
2815 | */ | |
4f3f4cf3 | 2816 | if (pwq->nr_active && need_to_create_worker(pool)) { |
a9b8a985 | 2817 | raw_spin_lock(&wq_mayday_lock); |
e66b39af TH |
2818 | /* |
2819 | * Queue iff we aren't racing destruction | |
2820 | * and somebody else hasn't queued it already. | |
2821 | */ | |
2822 | if (wq->rescuer && list_empty(&pwq->mayday_node)) { | |
2823 | get_pwq(pwq); | |
2824 | list_add_tail(&pwq->mayday_node, &wq->maydays); | |
2825 | } | |
a9b8a985 | 2826 | raw_spin_unlock(&wq_mayday_lock); |
008847f6 N |
2827 | } |
2828 | } | |
7576958a | 2829 | |
77668c8b LJ |
2830 | /* |
2831 | * Put the reference grabbed by send_mayday(). @pool won't | |
13b1d625 | 2832 | * go away while we're still attached to it. |
77668c8b LJ |
2833 | */ |
2834 | put_pwq(pwq); | |
2835 | ||
7576958a | 2836 | /* |
d8ca83e6 | 2837 | * Leave this pool. If need_more_worker() is %true, notify a |
7576958a TH |
2838 | * regular worker; otherwise, we end up with 0 concurrency |
2839 | * and stalling the execution. | |
2840 | */ | |
d8ca83e6 | 2841 | if (need_more_worker(pool)) |
63d95a91 | 2842 | wake_up_worker(pool); |
7576958a | 2843 | |
a9b8a985 | 2844 | raw_spin_unlock_irq(&pool->lock); |
13b1d625 | 2845 | |
a2d812a2 | 2846 | worker_detach_from_pool(rescuer); |
13b1d625 | 2847 | |
a9b8a985 | 2848 | raw_spin_lock_irq(&wq_mayday_lock); |
e22bee78 TH |
2849 | } |
2850 | ||
a9b8a985 | 2851 | raw_spin_unlock_irq(&wq_mayday_lock); |
493a1724 | 2852 | |
4d595b86 LJ |
2853 | if (should_stop) { |
2854 | __set_current_state(TASK_RUNNING); | |
197f6acc | 2855 | set_pf_worker(false); |
4d595b86 LJ |
2856 | return 0; |
2857 | } | |
2858 | ||
111c225a TH |
2859 | /* rescuers should never participate in concurrency management */ |
2860 | WARN_ON_ONCE(!(rescuer->flags & WORKER_NOT_RUNNING)); | |
e22bee78 TH |
2861 | schedule(); |
2862 | goto repeat; | |
1da177e4 LT |
2863 | } |
2864 | ||
fca839c0 TH |
2865 | /** |
2866 | * check_flush_dependency - check for flush dependency sanity | |
2867 | * @target_wq: workqueue being flushed | |
2868 | * @target_work: work item being flushed (NULL for workqueue flushes) | |
2869 | * | |
2870 | * %current is trying to flush the whole @target_wq or @target_work on it. | |
2871 | * If @target_wq doesn't have %WQ_MEM_RECLAIM, verify that %current is not | |
2872 | * reclaiming memory or running on a workqueue which doesn't have | |
2873 | * %WQ_MEM_RECLAIM as that can break forward-progress guarantee leading to | |
2874 | * a deadlock. | |
2875 | */ | |
2876 | static void check_flush_dependency(struct workqueue_struct *target_wq, | |
2877 | struct work_struct *target_work) | |
2878 | { | |
2879 | work_func_t target_func = target_work ? target_work->func : NULL; | |
2880 | struct worker *worker; | |
2881 | ||
2882 | if (target_wq->flags & WQ_MEM_RECLAIM) | |
2883 | return; | |
2884 | ||
2885 | worker = current_wq_worker(); | |
2886 | ||
2887 | WARN_ONCE(current->flags & PF_MEMALLOC, | |
d75f773c | 2888 | "workqueue: PF_MEMALLOC task %d(%s) is flushing !WQ_MEM_RECLAIM %s:%ps", |
fca839c0 | 2889 | current->pid, current->comm, target_wq->name, target_func); |
23d11a58 TH |
2890 | WARN_ONCE(worker && ((worker->current_pwq->wq->flags & |
2891 | (WQ_MEM_RECLAIM | __WQ_LEGACY)) == WQ_MEM_RECLAIM), | |
d75f773c | 2892 | "workqueue: WQ_MEM_RECLAIM %s:%ps is flushing !WQ_MEM_RECLAIM %s:%ps", |
fca839c0 TH |
2893 | worker->current_pwq->wq->name, worker->current_func, |
2894 | target_wq->name, target_func); | |
2895 | } | |
2896 | ||
fc2e4d70 ON |
2897 | struct wq_barrier { |
2898 | struct work_struct work; | |
2899 | struct completion done; | |
2607d7a6 | 2900 | struct task_struct *task; /* purely informational */ |
fc2e4d70 ON |
2901 | }; |
2902 | ||
2903 | static void wq_barrier_func(struct work_struct *work) | |
2904 | { | |
2905 | struct wq_barrier *barr = container_of(work, struct wq_barrier, work); | |
2906 | complete(&barr->done); | |
2907 | } | |
2908 | ||
4690c4ab TH |
2909 | /** |
2910 | * insert_wq_barrier - insert a barrier work | |
112202d9 | 2911 | * @pwq: pwq to insert barrier into |
4690c4ab | 2912 | * @barr: wq_barrier to insert |
affee4b2 TH |
2913 | * @target: target work to attach @barr to |
2914 | * @worker: worker currently executing @target, NULL if @target is not executing | |
4690c4ab | 2915 | * |
affee4b2 TH |
2916 | * @barr is linked to @target such that @barr is completed only after |
2917 | * @target finishes execution. Please note that the ordering | |
2918 | * guarantee is observed only with respect to @target and on the local | |
2919 | * cpu. | |
2920 | * | |
2921 | * Currently, a queued barrier can't be canceled. This is because | |
2922 | * try_to_grab_pending() can't determine whether the work to be | |
2923 | * grabbed is at the head of the queue and thus can't clear LINKED | |
2924 | * flag of the previous work while there must be a valid next work | |
2925 | * after a work with LINKED flag set. | |
2926 | * | |
2927 | * Note that when @worker is non-NULL, @target may be modified | |
112202d9 | 2928 | * underneath us, so we can't reliably determine pwq from @target. |
4690c4ab TH |
2929 | * |
2930 | * CONTEXT: | |
a9b8a985 | 2931 | * raw_spin_lock_irq(pool->lock). |
4690c4ab | 2932 | */ |
112202d9 | 2933 | static void insert_wq_barrier(struct pool_workqueue *pwq, |
affee4b2 TH |
2934 | struct wq_barrier *barr, |
2935 | struct work_struct *target, struct worker *worker) | |
fc2e4d70 | 2936 | { |
d812796e LJ |
2937 | unsigned int work_flags = 0; |
2938 | unsigned int work_color; | |
affee4b2 | 2939 | struct list_head *head; |
affee4b2 | 2940 | |
dc186ad7 | 2941 | /* |
d565ed63 | 2942 | * debugobject calls are safe here even with pool->lock locked |
dc186ad7 TG |
2943 | * as we know for sure that this will not trigger any of the |
2944 | * checks and call back into the fixup functions where we | |
2945 | * might deadlock. | |
2946 | */ | |
ca1cab37 | 2947 | INIT_WORK_ONSTACK(&barr->work, wq_barrier_func); |
22df02bb | 2948 | __set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(&barr->work)); |
52fa5bc5 | 2949 | |
fd1a5b04 BP |
2950 | init_completion_map(&barr->done, &target->lockdep_map); |
2951 | ||
2607d7a6 | 2952 | barr->task = current; |
83c22520 | 2953 | |
018f3a13 LJ |
2954 | /* The barrier work item does not participate in pwq->nr_active. */ |
2955 | work_flags |= WORK_STRUCT_INACTIVE; | |
2956 | ||
affee4b2 TH |
2957 | /* |
2958 | * If @target is currently being executed, schedule the | |
2959 | * barrier to the worker; otherwise, put it after @target. | |
2960 | */ | |
d812796e | 2961 | if (worker) { |
affee4b2 | 2962 | head = worker->scheduled.next; |
d812796e LJ |
2963 | work_color = worker->current_color; |
2964 | } else { | |
affee4b2 TH |
2965 | unsigned long *bits = work_data_bits(target); |
2966 | ||
2967 | head = target->entry.next; | |
2968 | /* there can already be other linked works, inherit and set */ | |
d21cece0 | 2969 | work_flags |= *bits & WORK_STRUCT_LINKED; |
d812796e | 2970 | work_color = get_work_color(*bits); |
affee4b2 TH |
2971 | __set_bit(WORK_STRUCT_LINKED_BIT, bits); |
2972 | } | |
2973 | ||
d812796e LJ |
2974 | pwq->nr_in_flight[work_color]++; |
2975 | work_flags |= work_color_to_flags(work_color); | |
2976 | ||
d21cece0 | 2977 | insert_work(pwq, &barr->work, head, work_flags); |
fc2e4d70 ON |
2978 | } |
2979 | ||
73f53c4a | 2980 | /** |
112202d9 | 2981 | * flush_workqueue_prep_pwqs - prepare pwqs for workqueue flushing |
73f53c4a TH |
2982 | * @wq: workqueue being flushed |
2983 | * @flush_color: new flush color, < 0 for no-op | |
2984 | * @work_color: new work color, < 0 for no-op | |
2985 | * | |
112202d9 | 2986 | * Prepare pwqs for workqueue flushing. |
73f53c4a | 2987 | * |
112202d9 TH |
2988 | * If @flush_color is non-negative, flush_color on all pwqs should be |
2989 | * -1. If no pwq has in-flight commands at the specified color, all | |
2990 | * pwq->flush_color's stay at -1 and %false is returned. If any pwq | |
2991 | * has in flight commands, its pwq->flush_color is set to | |
2992 | * @flush_color, @wq->nr_pwqs_to_flush is updated accordingly, pwq | |
73f53c4a TH |
2993 | * wakeup logic is armed and %true is returned. |
2994 | * | |
2995 | * The caller should have initialized @wq->first_flusher prior to | |
2996 | * calling this function with non-negative @flush_color. If | |
2997 | * @flush_color is negative, no flush color update is done and %false | |
2998 | * is returned. | |
2999 | * | |
112202d9 | 3000 | * If @work_color is non-negative, all pwqs should have the same |
73f53c4a TH |
3001 | * work_color which is previous to @work_color and all will be |
3002 | * advanced to @work_color. | |
3003 | * | |
3004 | * CONTEXT: | |
3c25a55d | 3005 | * mutex_lock(wq->mutex). |
73f53c4a | 3006 | * |
d185af30 | 3007 | * Return: |
73f53c4a TH |
3008 | * %true if @flush_color >= 0 and there's something to flush. %false |
3009 | * otherwise. | |
3010 | */ | |
112202d9 | 3011 | static bool flush_workqueue_prep_pwqs(struct workqueue_struct *wq, |
73f53c4a | 3012 | int flush_color, int work_color) |
1da177e4 | 3013 | { |
73f53c4a | 3014 | bool wait = false; |
49e3cf44 | 3015 | struct pool_workqueue *pwq; |
1da177e4 | 3016 | |
73f53c4a | 3017 | if (flush_color >= 0) { |
6183c009 | 3018 | WARN_ON_ONCE(atomic_read(&wq->nr_pwqs_to_flush)); |
112202d9 | 3019 | atomic_set(&wq->nr_pwqs_to_flush, 1); |
1da177e4 | 3020 | } |
2355b70f | 3021 | |
49e3cf44 | 3022 | for_each_pwq(pwq, wq) { |
112202d9 | 3023 | struct worker_pool *pool = pwq->pool; |
fc2e4d70 | 3024 | |
a9b8a985 | 3025 | raw_spin_lock_irq(&pool->lock); |
83c22520 | 3026 | |
73f53c4a | 3027 | if (flush_color >= 0) { |
6183c009 | 3028 | WARN_ON_ONCE(pwq->flush_color != -1); |
fc2e4d70 | 3029 | |
112202d9 TH |
3030 | if (pwq->nr_in_flight[flush_color]) { |
3031 | pwq->flush_color = flush_color; | |
3032 | atomic_inc(&wq->nr_pwqs_to_flush); | |
73f53c4a TH |
3033 | wait = true; |
3034 | } | |
3035 | } | |
1da177e4 | 3036 | |
73f53c4a | 3037 | if (work_color >= 0) { |
6183c009 | 3038 | WARN_ON_ONCE(work_color != work_next_color(pwq->work_color)); |
112202d9 | 3039 | pwq->work_color = work_color; |
73f53c4a | 3040 | } |
1da177e4 | 3041 | |
a9b8a985 | 3042 | raw_spin_unlock_irq(&pool->lock); |
1da177e4 | 3043 | } |
2355b70f | 3044 | |
112202d9 | 3045 | if (flush_color >= 0 && atomic_dec_and_test(&wq->nr_pwqs_to_flush)) |
73f53c4a | 3046 | complete(&wq->first_flusher->done); |
14441960 | 3047 | |
73f53c4a | 3048 | return wait; |
1da177e4 LT |
3049 | } |
3050 | ||
0fcb78c2 | 3051 | /** |
c4f135d6 | 3052 | * __flush_workqueue - ensure that any scheduled work has run to completion. |
0fcb78c2 | 3053 | * @wq: workqueue to flush |
1da177e4 | 3054 | * |
c5aa87bb TH |
3055 | * This function sleeps until all work items which were queued on entry |
3056 | * have finished execution, but it is not livelocked by new incoming ones. | |
1da177e4 | 3057 | */ |
c4f135d6 | 3058 | void __flush_workqueue(struct workqueue_struct *wq) |
1da177e4 | 3059 | { |
73f53c4a TH |
3060 | struct wq_flusher this_flusher = { |
3061 | .list = LIST_HEAD_INIT(this_flusher.list), | |
3062 | .flush_color = -1, | |
fd1a5b04 | 3063 | .done = COMPLETION_INITIALIZER_ONSTACK_MAP(this_flusher.done, wq->lockdep_map), |
73f53c4a TH |
3064 | }; |
3065 | int next_color; | |
1da177e4 | 3066 | |
3347fa09 TH |
3067 | if (WARN_ON(!wq_online)) |
3068 | return; | |
3069 | ||
87915adc JB |
3070 | lock_map_acquire(&wq->lockdep_map); |
3071 | lock_map_release(&wq->lockdep_map); | |
3072 | ||
3c25a55d | 3073 | mutex_lock(&wq->mutex); |
73f53c4a TH |
3074 | |
3075 | /* | |
3076 | * Start-to-wait phase | |
3077 | */ | |
3078 | next_color = work_next_color(wq->work_color); | |
3079 | ||
3080 | if (next_color != wq->flush_color) { | |
3081 | /* | |
3082 | * Color space is not full. The current work_color | |
3083 | * becomes our flush_color and work_color is advanced | |
3084 | * by one. | |
3085 | */ | |
6183c009 | 3086 | WARN_ON_ONCE(!list_empty(&wq->flusher_overflow)); |
73f53c4a TH |
3087 | this_flusher.flush_color = wq->work_color; |
3088 | wq->work_color = next_color; | |
3089 | ||
3090 | if (!wq->first_flusher) { | |
3091 | /* no flush in progress, become the first flusher */ | |
6183c009 | 3092 | WARN_ON_ONCE(wq->flush_color != this_flusher.flush_color); |
73f53c4a TH |
3093 | |
3094 | wq->first_flusher = &this_flusher; | |
3095 | ||
112202d9 | 3096 | if (!flush_workqueue_prep_pwqs(wq, wq->flush_color, |
73f53c4a TH |
3097 | wq->work_color)) { |
3098 | /* nothing to flush, done */ | |
3099 | wq->flush_color = next_color; | |
3100 | wq->first_flusher = NULL; | |
3101 | goto out_unlock; | |
3102 | } | |
3103 | } else { | |
3104 | /* wait in queue */ | |
6183c009 | 3105 | WARN_ON_ONCE(wq->flush_color == this_flusher.flush_color); |
73f53c4a | 3106 | list_add_tail(&this_flusher.list, &wq->flusher_queue); |
112202d9 | 3107 | flush_workqueue_prep_pwqs(wq, -1, wq->work_color); |
73f53c4a TH |
3108 | } |
3109 | } else { | |
3110 | /* | |
3111 | * Oops, color space is full, wait on overflow queue. | |
3112 | * The next flush completion will assign us | |
3113 | * flush_color and transfer to flusher_queue. | |
3114 | */ | |
3115 | list_add_tail(&this_flusher.list, &wq->flusher_overflow); | |
3116 | } | |
3117 | ||
fca839c0 TH |
3118 | check_flush_dependency(wq, NULL); |
3119 | ||
3c25a55d | 3120 | mutex_unlock(&wq->mutex); |
73f53c4a TH |
3121 | |
3122 | wait_for_completion(&this_flusher.done); | |
3123 | ||
3124 | /* | |
3125 | * Wake-up-and-cascade phase | |
3126 | * | |
3127 | * First flushers are responsible for cascading flushes and | |
3128 | * handling overflow. Non-first flushers can simply return. | |
3129 | */ | |
00d5d15b | 3130 | if (READ_ONCE(wq->first_flusher) != &this_flusher) |
73f53c4a TH |
3131 | return; |
3132 | ||
3c25a55d | 3133 | mutex_lock(&wq->mutex); |
73f53c4a | 3134 | |
4ce48b37 TH |
3135 | /* we might have raced, check again with mutex held */ |
3136 | if (wq->first_flusher != &this_flusher) | |
3137 | goto out_unlock; | |
3138 | ||
00d5d15b | 3139 | WRITE_ONCE(wq->first_flusher, NULL); |
73f53c4a | 3140 | |
6183c009 TH |
3141 | WARN_ON_ONCE(!list_empty(&this_flusher.list)); |
3142 | WARN_ON_ONCE(wq->flush_color != this_flusher.flush_color); | |
73f53c4a TH |
3143 | |
3144 | while (true) { | |
3145 | struct wq_flusher *next, *tmp; | |
3146 | ||
3147 | /* complete all the flushers sharing the current flush color */ | |
3148 | list_for_each_entry_safe(next, tmp, &wq->flusher_queue, list) { | |
3149 | if (next->flush_color != wq->flush_color) | |
3150 | break; | |
3151 | list_del_init(&next->list); | |
3152 | complete(&next->done); | |
3153 | } | |
3154 | ||
6183c009 TH |
3155 | WARN_ON_ONCE(!list_empty(&wq->flusher_overflow) && |
3156 | wq->flush_color != work_next_color(wq->work_color)); | |
73f53c4a TH |
3157 | |
3158 | /* this flush_color is finished, advance by one */ | |
3159 | wq->flush_color = work_next_color(wq->flush_color); | |
3160 | ||
3161 | /* one color has been freed, handle overflow queue */ | |
3162 | if (!list_empty(&wq->flusher_overflow)) { | |
3163 | /* | |
3164 | * Assign the same color to all overflowed | |
3165 | * flushers, advance work_color and append to | |
3166 | * flusher_queue. This is the start-to-wait | |
3167 | * phase for these overflowed flushers. | |
3168 | */ | |
3169 | list_for_each_entry(tmp, &wq->flusher_overflow, list) | |
3170 | tmp->flush_color = wq->work_color; | |
3171 | ||
3172 | wq->work_color = work_next_color(wq->work_color); | |
3173 | ||
3174 | list_splice_tail_init(&wq->flusher_overflow, | |
3175 | &wq->flusher_queue); | |
112202d9 | 3176 | flush_workqueue_prep_pwqs(wq, -1, wq->work_color); |
73f53c4a TH |
3177 | } |
3178 | ||
3179 | if (list_empty(&wq->flusher_queue)) { | |
6183c009 | 3180 | WARN_ON_ONCE(wq->flush_color != wq->work_color); |
73f53c4a TH |
3181 | break; |
3182 | } | |
3183 | ||
3184 | /* | |
3185 | * Need to flush more colors. Make the next flusher | |
112202d9 | 3186 | * the new first flusher and arm pwqs. |
73f53c4a | 3187 | */ |
6183c009 TH |
3188 | WARN_ON_ONCE(wq->flush_color == wq->work_color); |
3189 | WARN_ON_ONCE(wq->flush_color != next->flush_color); | |
73f53c4a TH |
3190 | |
3191 | list_del_init(&next->list); | |
3192 | wq->first_flusher = next; | |
3193 | ||
112202d9 | 3194 | if (flush_workqueue_prep_pwqs(wq, wq->flush_color, -1)) |
73f53c4a TH |
3195 | break; |
3196 | ||
3197 | /* | |
3198 | * Meh... this color is already done, clear first | |
3199 | * flusher and repeat cascading. | |
3200 | */ | |
3201 | wq->first_flusher = NULL; | |
3202 | } | |
3203 | ||
3204 | out_unlock: | |
3c25a55d | 3205 | mutex_unlock(&wq->mutex); |
1da177e4 | 3206 | } |
c4f135d6 | 3207 | EXPORT_SYMBOL(__flush_workqueue); |
1da177e4 | 3208 | |
9c5a2ba7 TH |
3209 | /** |
3210 | * drain_workqueue - drain a workqueue | |
3211 | * @wq: workqueue to drain | |
3212 | * | |
3213 | * Wait until the workqueue becomes empty. While draining is in progress, | |
3214 | * only chain queueing is allowed. IOW, only currently pending or running | |
3215 | * work items on @wq can queue further work items on it. @wq is flushed | |
b749b1b6 | 3216 | * repeatedly until it becomes empty. The number of flushing is determined |
9c5a2ba7 TH |
3217 | * by the depth of chaining and should be relatively short. Whine if it |
3218 | * takes too long. | |
3219 | */ | |
3220 | void drain_workqueue(struct workqueue_struct *wq) | |
3221 | { | |
3222 | unsigned int flush_cnt = 0; | |
49e3cf44 | 3223 | struct pool_workqueue *pwq; |
9c5a2ba7 TH |
3224 | |
3225 | /* | |
3226 | * __queue_work() needs to test whether there are drainers, is much | |
3227 | * hotter than drain_workqueue() and already looks at @wq->flags. | |
618b01eb | 3228 | * Use __WQ_DRAINING so that queue doesn't have to check nr_drainers. |
9c5a2ba7 | 3229 | */ |
87fc741e | 3230 | mutex_lock(&wq->mutex); |
9c5a2ba7 | 3231 | if (!wq->nr_drainers++) |
618b01eb | 3232 | wq->flags |= __WQ_DRAINING; |
87fc741e | 3233 | mutex_unlock(&wq->mutex); |
9c5a2ba7 | 3234 | reflush: |
c4f135d6 | 3235 | __flush_workqueue(wq); |
9c5a2ba7 | 3236 | |
b09f4fd3 | 3237 | mutex_lock(&wq->mutex); |
76af4d93 | 3238 | |
49e3cf44 | 3239 | for_each_pwq(pwq, wq) { |
fa2563e4 | 3240 | bool drained; |
9c5a2ba7 | 3241 | |
a9b8a985 | 3242 | raw_spin_lock_irq(&pwq->pool->lock); |
f97a4a1a | 3243 | drained = !pwq->nr_active && list_empty(&pwq->inactive_works); |
a9b8a985 | 3244 | raw_spin_unlock_irq(&pwq->pool->lock); |
fa2563e4 TT |
3245 | |
3246 | if (drained) | |
9c5a2ba7 TH |
3247 | continue; |
3248 | ||
3249 | if (++flush_cnt == 10 || | |
3250 | (flush_cnt % 100 == 0 && flush_cnt <= 1000)) | |
e9ad2eb3 SZ |
3251 | pr_warn("workqueue %s: %s() isn't complete after %u tries\n", |
3252 | wq->name, __func__, flush_cnt); | |
76af4d93 | 3253 | |
b09f4fd3 | 3254 | mutex_unlock(&wq->mutex); |
9c5a2ba7 TH |
3255 | goto reflush; |
3256 | } | |
3257 | ||
9c5a2ba7 | 3258 | if (!--wq->nr_drainers) |
618b01eb | 3259 | wq->flags &= ~__WQ_DRAINING; |
87fc741e | 3260 | mutex_unlock(&wq->mutex); |
9c5a2ba7 TH |
3261 | } |
3262 | EXPORT_SYMBOL_GPL(drain_workqueue); | |
3263 | ||
d6e89786 JB |
3264 | static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr, |
3265 | bool from_cancel) | |
db700897 | 3266 | { |
affee4b2 | 3267 | struct worker *worker = NULL; |
c9e7cf27 | 3268 | struct worker_pool *pool; |
112202d9 | 3269 | struct pool_workqueue *pwq; |
db700897 ON |
3270 | |
3271 | might_sleep(); | |
fa1b54e6 | 3272 | |
24acfb71 | 3273 | rcu_read_lock(); |
c9e7cf27 | 3274 | pool = get_work_pool(work); |
fa1b54e6 | 3275 | if (!pool) { |
24acfb71 | 3276 | rcu_read_unlock(); |
baf59022 | 3277 | return false; |
fa1b54e6 | 3278 | } |
db700897 | 3279 | |
a9b8a985 | 3280 | raw_spin_lock_irq(&pool->lock); |
0b3dae68 | 3281 | /* see the comment in try_to_grab_pending() with the same code */ |
112202d9 TH |
3282 | pwq = get_work_pwq(work); |
3283 | if (pwq) { | |
3284 | if (unlikely(pwq->pool != pool)) | |
4690c4ab | 3285 | goto already_gone; |
606a5020 | 3286 | } else { |
c9e7cf27 | 3287 | worker = find_worker_executing_work(pool, work); |
affee4b2 | 3288 | if (!worker) |
4690c4ab | 3289 | goto already_gone; |
112202d9 | 3290 | pwq = worker->current_pwq; |
606a5020 | 3291 | } |
db700897 | 3292 | |
fca839c0 TH |
3293 | check_flush_dependency(pwq->wq, work); |
3294 | ||
112202d9 | 3295 | insert_wq_barrier(pwq, barr, work, worker); |
a9b8a985 | 3296 | raw_spin_unlock_irq(&pool->lock); |
7a22ad75 | 3297 | |
e159489b | 3298 | /* |
a1d14934 PZ |
3299 | * Force a lock recursion deadlock when using flush_work() inside a |
3300 | * single-threaded or rescuer equipped workqueue. | |
3301 | * | |
3302 | * For single threaded workqueues the deadlock happens when the work | |
3303 | * is after the work issuing the flush_work(). For rescuer equipped | |
3304 | * workqueues the deadlock happens when the rescuer stalls, blocking | |
3305 | * forward progress. | |
e159489b | 3306 | */ |
d6e89786 JB |
3307 | if (!from_cancel && |
3308 | (pwq->wq->saved_max_active == 1 || pwq->wq->rescuer)) { | |
112202d9 | 3309 | lock_map_acquire(&pwq->wq->lockdep_map); |
a1d14934 PZ |
3310 | lock_map_release(&pwq->wq->lockdep_map); |
3311 | } | |
24acfb71 | 3312 | rcu_read_unlock(); |
401a8d04 | 3313 | return true; |
4690c4ab | 3314 | already_gone: |
a9b8a985 | 3315 | raw_spin_unlock_irq(&pool->lock); |
24acfb71 | 3316 | rcu_read_unlock(); |
401a8d04 | 3317 | return false; |
db700897 | 3318 | } |
baf59022 | 3319 | |
d6e89786 JB |
3320 | static bool __flush_work(struct work_struct *work, bool from_cancel) |
3321 | { | |
3322 | struct wq_barrier barr; | |
3323 | ||
3324 | if (WARN_ON(!wq_online)) | |
3325 | return false; | |
3326 | ||
4d43d395 TH |
3327 | if (WARN_ON(!work->func)) |
3328 | return false; | |
3329 | ||
c0feea59 TH |
3330 | lock_map_acquire(&work->lockdep_map); |
3331 | lock_map_release(&work->lockdep_map); | |
87915adc | 3332 | |
d6e89786 JB |
3333 | if (start_flush_work(work, &barr, from_cancel)) { |
3334 | wait_for_completion(&barr.done); | |
3335 | destroy_work_on_stack(&barr.work); | |
3336 | return true; | |
3337 | } else { | |
3338 | return false; | |
3339 | } | |
3340 | } | |
3341 | ||
baf59022 TH |
3342 | /** |
3343 | * flush_work - wait for a work to finish executing the last queueing instance | |
3344 | * @work: the work to flush | |
3345 | * | |
606a5020 TH |
3346 | * Wait until @work has finished execution. @work is guaranteed to be idle |
3347 | * on return if it hasn't been requeued since flush started. | |
baf59022 | 3348 | * |
d185af30 | 3349 | * Return: |
baf59022 TH |
3350 | * %true if flush_work() waited for the work to finish execution, |
3351 | * %false if it was already idle. | |
3352 | */ | |
3353 | bool flush_work(struct work_struct *work) | |
3354 | { | |
d6e89786 | 3355 | return __flush_work(work, false); |
6e84d644 | 3356 | } |
606a5020 | 3357 | EXPORT_SYMBOL_GPL(flush_work); |
6e84d644 | 3358 | |
8603e1b3 | 3359 | struct cwt_wait { |
ac6424b9 | 3360 | wait_queue_entry_t wait; |
8603e1b3 TH |
3361 | struct work_struct *work; |
3362 | }; | |
3363 | ||
ac6424b9 | 3364 | static int cwt_wakefn(wait_queue_entry_t *wait, unsigned mode, int sync, void *key) |
8603e1b3 TH |
3365 | { |
3366 | struct cwt_wait *cwait = container_of(wait, struct cwt_wait, wait); | |
3367 | ||
3368 | if (cwait->work != key) | |
3369 | return 0; | |
3370 | return autoremove_wake_function(wait, mode, sync, key); | |
3371 | } | |
3372 | ||
36e227d2 | 3373 | static bool __cancel_work_timer(struct work_struct *work, bool is_dwork) |
1f1f642e | 3374 | { |
8603e1b3 | 3375 | static DECLARE_WAIT_QUEUE_HEAD(cancel_waitq); |
bbb68dfa | 3376 | unsigned long flags; |
1f1f642e ON |
3377 | int ret; |
3378 | ||
3379 | do { | |
bbb68dfa TH |
3380 | ret = try_to_grab_pending(work, is_dwork, &flags); |
3381 | /* | |
8603e1b3 TH |
3382 | * If someone else is already canceling, wait for it to |
3383 | * finish. flush_work() doesn't work for PREEMPT_NONE | |
3384 | * because we may get scheduled between @work's completion | |
3385 | * and the other canceling task resuming and clearing | |
3386 | * CANCELING - flush_work() will return false immediately | |
3387 | * as @work is no longer busy, try_to_grab_pending() will | |
3388 | * return -ENOENT as @work is still being canceled and the | |
3389 | * other canceling task won't be able to clear CANCELING as | |
3390 | * we're hogging the CPU. | |
3391 | * | |
3392 | * Let's wait for completion using a waitqueue. As this | |
3393 | * may lead to the thundering herd problem, use a custom | |
3394 | * wake function which matches @work along with exclusive | |
3395 | * wait and wakeup. | |
bbb68dfa | 3396 | */ |
8603e1b3 TH |
3397 | if (unlikely(ret == -ENOENT)) { |
3398 | struct cwt_wait cwait; | |
3399 | ||
3400 | init_wait(&cwait.wait); | |
3401 | cwait.wait.func = cwt_wakefn; | |
3402 | cwait.work = work; | |
3403 | ||
3404 | prepare_to_wait_exclusive(&cancel_waitq, &cwait.wait, | |
3405 | TASK_UNINTERRUPTIBLE); | |
3406 | if (work_is_canceling(work)) | |
3407 | schedule(); | |
3408 | finish_wait(&cancel_waitq, &cwait.wait); | |
3409 | } | |
1f1f642e ON |
3410 | } while (unlikely(ret < 0)); |
3411 | ||
bbb68dfa TH |
3412 | /* tell other tasks trying to grab @work to back off */ |
3413 | mark_work_canceling(work); | |
3414 | local_irq_restore(flags); | |
3415 | ||
3347fa09 TH |
3416 | /* |
3417 | * This allows canceling during early boot. We know that @work | |
3418 | * isn't executing. | |
3419 | */ | |
3420 | if (wq_online) | |
d6e89786 | 3421 | __flush_work(work, true); |
3347fa09 | 3422 | |
7a22ad75 | 3423 | clear_work_data(work); |
8603e1b3 TH |
3424 | |
3425 | /* | |
3426 | * Paired with prepare_to_wait() above so that either | |
3427 | * waitqueue_active() is visible here or !work_is_canceling() is | |
3428 | * visible there. | |
3429 | */ | |
3430 | smp_mb(); | |
3431 | if (waitqueue_active(&cancel_waitq)) | |
3432 | __wake_up(&cancel_waitq, TASK_NORMAL, 1, work); | |
3433 | ||
1f1f642e ON |
3434 | return ret; |
3435 | } | |
3436 | ||
6e84d644 | 3437 | /** |
401a8d04 TH |
3438 | * cancel_work_sync - cancel a work and wait for it to finish |
3439 | * @work: the work to cancel | |
6e84d644 | 3440 | * |
401a8d04 TH |
3441 | * Cancel @work and wait for its execution to finish. This function |
3442 | * can be used even if the work re-queues itself or migrates to | |
3443 | * another workqueue. On return from this function, @work is | |
3444 | * guaranteed to be not pending or executing on any CPU. | |
1f1f642e | 3445 | * |
401a8d04 TH |
3446 | * cancel_work_sync(&delayed_work->work) must not be used for |
3447 | * delayed_work's. Use cancel_delayed_work_sync() instead. | |
6e84d644 | 3448 | * |
401a8d04 | 3449 | * The caller must ensure that the workqueue on which @work was last |
6e84d644 | 3450 | * queued can't be destroyed before this function returns. |
401a8d04 | 3451 | * |
d185af30 | 3452 | * Return: |
401a8d04 | 3453 | * %true if @work was pending, %false otherwise. |
6e84d644 | 3454 | */ |
401a8d04 | 3455 | bool cancel_work_sync(struct work_struct *work) |
6e84d644 | 3456 | { |
36e227d2 | 3457 | return __cancel_work_timer(work, false); |
b89deed3 | 3458 | } |
28e53bdd | 3459 | EXPORT_SYMBOL_GPL(cancel_work_sync); |
b89deed3 | 3460 | |
6e84d644 | 3461 | /** |
401a8d04 TH |
3462 | * flush_delayed_work - wait for a dwork to finish executing the last queueing |
3463 | * @dwork: the delayed work to flush | |
6e84d644 | 3464 | * |
401a8d04 TH |
3465 | * Delayed timer is cancelled and the pending work is queued for |
3466 | * immediate execution. Like flush_work(), this function only | |
3467 | * considers the last queueing instance of @dwork. | |
1f1f642e | 3468 | * |
d185af30 | 3469 | * Return: |
401a8d04 TH |
3470 | * %true if flush_work() waited for the work to finish execution, |
3471 | * %false if it was already idle. | |
6e84d644 | 3472 | */ |
401a8d04 TH |
3473 | bool flush_delayed_work(struct delayed_work *dwork) |
3474 | { | |
8930caba | 3475 | local_irq_disable(); |
401a8d04 | 3476 | if (del_timer_sync(&dwork->timer)) |
60c057bc | 3477 | __queue_work(dwork->cpu, dwork->wq, &dwork->work); |
8930caba | 3478 | local_irq_enable(); |
401a8d04 TH |
3479 | return flush_work(&dwork->work); |
3480 | } | |
3481 | EXPORT_SYMBOL(flush_delayed_work); | |
3482 | ||
05f0fe6b TH |
3483 | /** |
3484 | * flush_rcu_work - wait for a rwork to finish executing the last queueing | |
3485 | * @rwork: the rcu work to flush | |
3486 | * | |
3487 | * Return: | |
3488 | * %true if flush_rcu_work() waited for the work to finish execution, | |
3489 | * %false if it was already idle. | |
3490 | */ | |
3491 | bool flush_rcu_work(struct rcu_work *rwork) | |
3492 | { | |
3493 | if (test_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(&rwork->work))) { | |
3494 | rcu_barrier(); | |
3495 | flush_work(&rwork->work); | |
3496 | return true; | |
3497 | } else { | |
3498 | return flush_work(&rwork->work); | |
3499 | } | |
3500 | } | |
3501 | EXPORT_SYMBOL(flush_rcu_work); | |
3502 | ||
f72b8792 JA |
3503 | static bool __cancel_work(struct work_struct *work, bool is_dwork) |
3504 | { | |
3505 | unsigned long flags; | |
3506 | int ret; | |
3507 | ||
3508 | do { | |
3509 | ret = try_to_grab_pending(work, is_dwork, &flags); | |
3510 | } while (unlikely(ret == -EAGAIN)); | |
3511 | ||
3512 | if (unlikely(ret < 0)) | |
3513 | return false; | |
3514 | ||
3515 | set_work_pool_and_clear_pending(work, get_work_pool_id(work)); | |
3516 | local_irq_restore(flags); | |
3517 | return ret; | |
3518 | } | |
3519 | ||
73b4b532 AG |
3520 | /* |
3521 | * See cancel_delayed_work() | |
3522 | */ | |
3523 | bool cancel_work(struct work_struct *work) | |
3524 | { | |
3525 | return __cancel_work(work, false); | |
3526 | } | |
3527 | EXPORT_SYMBOL(cancel_work); | |
3528 | ||
09383498 | 3529 | /** |
57b30ae7 TH |
3530 | * cancel_delayed_work - cancel a delayed work |
3531 | * @dwork: delayed_work to cancel | |
09383498 | 3532 | * |
d185af30 YB |
3533 | * Kill off a pending delayed_work. |
3534 | * | |
3535 | * Return: %true if @dwork was pending and canceled; %false if it wasn't | |
3536 | * pending. | |
3537 | * | |
3538 | * Note: | |
3539 | * The work callback function may still be running on return, unless | |
3540 | * it returns %true and the work doesn't re-arm itself. Explicitly flush or | |
3541 | * use cancel_delayed_work_sync() to wait on it. | |
09383498 | 3542 | * |
57b30ae7 | 3543 | * This function is safe to call from any context including IRQ handler. |
09383498 | 3544 | */ |
57b30ae7 | 3545 | bool cancel_delayed_work(struct delayed_work *dwork) |
09383498 | 3546 | { |
f72b8792 | 3547 | return __cancel_work(&dwork->work, true); |
09383498 | 3548 | } |
57b30ae7 | 3549 | EXPORT_SYMBOL(cancel_delayed_work); |
09383498 | 3550 | |
401a8d04 TH |
3551 | /** |
3552 | * cancel_delayed_work_sync - cancel a delayed work and wait for it to finish | |
3553 | * @dwork: the delayed work cancel | |
3554 | * | |
3555 | * This is cancel_work_sync() for delayed works. | |
3556 | * | |
d185af30 | 3557 | * Return: |
401a8d04 TH |
3558 | * %true if @dwork was pending, %false otherwise. |
3559 | */ | |
3560 | bool cancel_delayed_work_sync(struct delayed_work *dwork) | |
6e84d644 | 3561 | { |
36e227d2 | 3562 | return __cancel_work_timer(&dwork->work, true); |
6e84d644 | 3563 | } |
f5a421a4 | 3564 | EXPORT_SYMBOL(cancel_delayed_work_sync); |
1da177e4 | 3565 | |
b6136773 | 3566 | /** |
31ddd871 | 3567 | * schedule_on_each_cpu - execute a function synchronously on each online CPU |
b6136773 | 3568 | * @func: the function to call |
b6136773 | 3569 | * |
31ddd871 TH |
3570 | * schedule_on_each_cpu() executes @func on each online CPU using the |
3571 | * system workqueue and blocks until all CPUs have completed. | |
b6136773 | 3572 | * schedule_on_each_cpu() is very slow. |
31ddd871 | 3573 | * |
d185af30 | 3574 | * Return: |
31ddd871 | 3575 | * 0 on success, -errno on failure. |
b6136773 | 3576 | */ |
65f27f38 | 3577 | int schedule_on_each_cpu(work_func_t func) |
15316ba8 CL |
3578 | { |
3579 | int cpu; | |
38f51568 | 3580 | struct work_struct __percpu *works; |
15316ba8 | 3581 | |
b6136773 AM |
3582 | works = alloc_percpu(struct work_struct); |
3583 | if (!works) | |
15316ba8 | 3584 | return -ENOMEM; |
b6136773 | 3585 | |
ffd8bea8 | 3586 | cpus_read_lock(); |
93981800 | 3587 | |
15316ba8 | 3588 | for_each_online_cpu(cpu) { |
9bfb1839 IM |
3589 | struct work_struct *work = per_cpu_ptr(works, cpu); |
3590 | ||
3591 | INIT_WORK(work, func); | |
b71ab8c2 | 3592 | schedule_work_on(cpu, work); |
65a64464 | 3593 | } |
93981800 TH |
3594 | |
3595 | for_each_online_cpu(cpu) | |
3596 | flush_work(per_cpu_ptr(works, cpu)); | |
3597 | ||
ffd8bea8 | 3598 | cpus_read_unlock(); |
b6136773 | 3599 | free_percpu(works); |
15316ba8 CL |
3600 | return 0; |
3601 | } | |
3602 | ||
1fa44eca JB |
3603 | /** |
3604 | * execute_in_process_context - reliably execute the routine with user context | |
3605 | * @fn: the function to execute | |
1fa44eca JB |
3606 | * @ew: guaranteed storage for the execute work structure (must |
3607 | * be available when the work executes) | |
3608 | * | |
3609 | * Executes the function immediately if process context is available, | |
3610 | * otherwise schedules the function for delayed execution. | |
3611 | * | |
d185af30 | 3612 | * Return: 0 - function was executed |
1fa44eca JB |
3613 | * 1 - function was scheduled for execution |
3614 | */ | |
65f27f38 | 3615 | int execute_in_process_context(work_func_t fn, struct execute_work *ew) |
1fa44eca JB |
3616 | { |
3617 | if (!in_interrupt()) { | |
65f27f38 | 3618 | fn(&ew->work); |
1fa44eca JB |
3619 | return 0; |
3620 | } | |
3621 | ||
65f27f38 | 3622 | INIT_WORK(&ew->work, fn); |
1fa44eca JB |
3623 | schedule_work(&ew->work); |
3624 | ||
3625 | return 1; | |
3626 | } | |
3627 | EXPORT_SYMBOL_GPL(execute_in_process_context); | |
3628 | ||
6ba94429 FW |
3629 | /** |
3630 | * free_workqueue_attrs - free a workqueue_attrs | |
3631 | * @attrs: workqueue_attrs to free | |
226223ab | 3632 | * |
6ba94429 | 3633 | * Undo alloc_workqueue_attrs(). |
226223ab | 3634 | */ |
513c98d0 | 3635 | void free_workqueue_attrs(struct workqueue_attrs *attrs) |
226223ab | 3636 | { |
6ba94429 FW |
3637 | if (attrs) { |
3638 | free_cpumask_var(attrs->cpumask); | |
3639 | kfree(attrs); | |
3640 | } | |
226223ab TH |
3641 | } |
3642 | ||
6ba94429 FW |
3643 | /** |
3644 | * alloc_workqueue_attrs - allocate a workqueue_attrs | |
6ba94429 FW |
3645 | * |
3646 | * Allocate a new workqueue_attrs, initialize with default settings and | |
3647 | * return it. | |
3648 | * | |
3649 | * Return: The allocated new workqueue_attr on success. %NULL on failure. | |
3650 | */ | |
513c98d0 | 3651 | struct workqueue_attrs *alloc_workqueue_attrs(void) |
226223ab | 3652 | { |
6ba94429 | 3653 | struct workqueue_attrs *attrs; |
226223ab | 3654 | |
be69d00d | 3655 | attrs = kzalloc(sizeof(*attrs), GFP_KERNEL); |
6ba94429 FW |
3656 | if (!attrs) |
3657 | goto fail; | |
be69d00d | 3658 | if (!alloc_cpumask_var(&attrs->cpumask, GFP_KERNEL)) |
6ba94429 FW |
3659 | goto fail; |
3660 | ||
3661 | cpumask_copy(attrs->cpumask, cpu_possible_mask); | |
3662 | return attrs; | |
3663 | fail: | |
3664 | free_workqueue_attrs(attrs); | |
3665 | return NULL; | |
226223ab TH |
3666 | } |
3667 | ||
6ba94429 FW |
3668 | static void copy_workqueue_attrs(struct workqueue_attrs *to, |
3669 | const struct workqueue_attrs *from) | |
226223ab | 3670 | { |
6ba94429 FW |
3671 | to->nice = from->nice; |
3672 | cpumask_copy(to->cpumask, from->cpumask); | |
3673 | /* | |
3674 | * Unlike hash and equality test, this function doesn't ignore | |
af73f5c9 TH |
3675 | * ->ordered as it is used for both pool and wq attrs. Instead, |
3676 | * get_unbound_pool() explicitly clears ->ordered after copying. | |
6ba94429 | 3677 | */ |
af73f5c9 | 3678 | to->ordered = from->ordered; |
226223ab TH |
3679 | } |
3680 | ||
6ba94429 FW |
3681 | /* hash value of the content of @attr */ |
3682 | static u32 wqattrs_hash(const struct workqueue_attrs *attrs) | |
226223ab | 3683 | { |
6ba94429 | 3684 | u32 hash = 0; |
226223ab | 3685 | |
6ba94429 FW |
3686 | hash = jhash_1word(attrs->nice, hash); |
3687 | hash = jhash(cpumask_bits(attrs->cpumask), | |
3688 | BITS_TO_LONGS(nr_cpumask_bits) * sizeof(long), hash); | |
3689 | return hash; | |
226223ab | 3690 | } |
226223ab | 3691 | |
6ba94429 FW |
3692 | /* content equality test */ |
3693 | static bool wqattrs_equal(const struct workqueue_attrs *a, | |
3694 | const struct workqueue_attrs *b) | |
226223ab | 3695 | { |
6ba94429 FW |
3696 | if (a->nice != b->nice) |
3697 | return false; | |
3698 | if (!cpumask_equal(a->cpumask, b->cpumask)) | |
3699 | return false; | |
3700 | return true; | |
226223ab TH |
3701 | } |
3702 | ||
0f36ee24 TH |
3703 | /* Update @attrs with actually available CPUs */ |
3704 | static void wqattrs_actualize_cpumask(struct workqueue_attrs *attrs, | |
3705 | const cpumask_t *unbound_cpumask) | |
3706 | { | |
3707 | /* | |
3708 | * Calculate the effective CPU mask of @attrs given @unbound_cpumask. If | |
3709 | * @attrs->cpumask doesn't overlap with @unbound_cpumask, we fallback to | |
3710 | * @unbound_cpumask. | |
3711 | */ | |
3712 | cpumask_and(attrs->cpumask, attrs->cpumask, unbound_cpumask); | |
3713 | if (unlikely(cpumask_empty(attrs->cpumask))) | |
3714 | cpumask_copy(attrs->cpumask, unbound_cpumask); | |
3715 | } | |
3716 | ||
6ba94429 FW |
3717 | /** |
3718 | * init_worker_pool - initialize a newly zalloc'd worker_pool | |
3719 | * @pool: worker_pool to initialize | |
3720 | * | |
402dd89d | 3721 | * Initialize a newly zalloc'd @pool. It also allocates @pool->attrs. |
6ba94429 FW |
3722 | * |
3723 | * Return: 0 on success, -errno on failure. Even on failure, all fields | |
3724 | * inside @pool proper are initialized and put_unbound_pool() can be called | |
3725 | * on @pool safely to release it. | |
3726 | */ | |
3727 | static int init_worker_pool(struct worker_pool *pool) | |
226223ab | 3728 | { |
a9b8a985 | 3729 | raw_spin_lock_init(&pool->lock); |
6ba94429 FW |
3730 | pool->id = -1; |
3731 | pool->cpu = -1; | |
3732 | pool->node = NUMA_NO_NODE; | |
3733 | pool->flags |= POOL_DISASSOCIATED; | |
82607adc | 3734 | pool->watchdog_ts = jiffies; |
6ba94429 FW |
3735 | INIT_LIST_HEAD(&pool->worklist); |
3736 | INIT_LIST_HEAD(&pool->idle_list); | |
3737 | hash_init(pool->busy_hash); | |
226223ab | 3738 | |
32a6c723 | 3739 | timer_setup(&pool->idle_timer, idle_worker_timeout, TIMER_DEFERRABLE); |
3f959aa3 | 3740 | INIT_WORK(&pool->idle_cull_work, idle_cull_fn); |
226223ab | 3741 | |
32a6c723 | 3742 | timer_setup(&pool->mayday_timer, pool_mayday_timeout, 0); |
226223ab | 3743 | |
6ba94429 | 3744 | INIT_LIST_HEAD(&pool->workers); |
e02b9312 | 3745 | INIT_LIST_HEAD(&pool->dying_workers); |
226223ab | 3746 | |
6ba94429 FW |
3747 | ida_init(&pool->worker_ida); |
3748 | INIT_HLIST_NODE(&pool->hash_node); | |
3749 | pool->refcnt = 1; | |
226223ab | 3750 | |
6ba94429 | 3751 | /* shouldn't fail above this point */ |
be69d00d | 3752 | pool->attrs = alloc_workqueue_attrs(); |
6ba94429 FW |
3753 | if (!pool->attrs) |
3754 | return -ENOMEM; | |
3755 | return 0; | |
226223ab TH |
3756 | } |
3757 | ||
669de8bd BVA |
3758 | #ifdef CONFIG_LOCKDEP |
3759 | static void wq_init_lockdep(struct workqueue_struct *wq) | |
3760 | { | |
3761 | char *lock_name; | |
3762 | ||
3763 | lockdep_register_key(&wq->key); | |
3764 | lock_name = kasprintf(GFP_KERNEL, "%s%s", "(wq_completion)", wq->name); | |
3765 | if (!lock_name) | |
3766 | lock_name = wq->name; | |
69a106c0 QC |
3767 | |
3768 | wq->lock_name = lock_name; | |
669de8bd BVA |
3769 | lockdep_init_map(&wq->lockdep_map, lock_name, &wq->key, 0); |
3770 | } | |
3771 | ||
3772 | static void wq_unregister_lockdep(struct workqueue_struct *wq) | |
3773 | { | |
3774 | lockdep_unregister_key(&wq->key); | |
3775 | } | |
3776 | ||
3777 | static void wq_free_lockdep(struct workqueue_struct *wq) | |
3778 | { | |
3779 | if (wq->lock_name != wq->name) | |
3780 | kfree(wq->lock_name); | |
3781 | } | |
3782 | #else | |
3783 | static void wq_init_lockdep(struct workqueue_struct *wq) | |
3784 | { | |
3785 | } | |
3786 | ||
3787 | static void wq_unregister_lockdep(struct workqueue_struct *wq) | |
3788 | { | |
3789 | } | |
3790 | ||
3791 | static void wq_free_lockdep(struct workqueue_struct *wq) | |
3792 | { | |
3793 | } | |
3794 | #endif | |
3795 | ||
6ba94429 | 3796 | static void rcu_free_wq(struct rcu_head *rcu) |
226223ab | 3797 | { |
6ba94429 FW |
3798 | struct workqueue_struct *wq = |
3799 | container_of(rcu, struct workqueue_struct, rcu); | |
226223ab | 3800 | |
669de8bd | 3801 | wq_free_lockdep(wq); |
636b927e TH |
3802 | free_percpu(wq->cpu_pwq); |
3803 | free_workqueue_attrs(wq->unbound_attrs); | |
6ba94429 | 3804 | kfree(wq); |
226223ab TH |
3805 | } |
3806 | ||
6ba94429 | 3807 | static void rcu_free_pool(struct rcu_head *rcu) |
226223ab | 3808 | { |
6ba94429 | 3809 | struct worker_pool *pool = container_of(rcu, struct worker_pool, rcu); |
226223ab | 3810 | |
6ba94429 FW |
3811 | ida_destroy(&pool->worker_ida); |
3812 | free_workqueue_attrs(pool->attrs); | |
3813 | kfree(pool); | |
226223ab TH |
3814 | } |
3815 | ||
6ba94429 FW |
3816 | /** |
3817 | * put_unbound_pool - put a worker_pool | |
3818 | * @pool: worker_pool to put | |
3819 | * | |
24acfb71 | 3820 | * Put @pool. If its refcnt reaches zero, it gets destroyed in RCU |
6ba94429 FW |
3821 | * safe manner. get_unbound_pool() calls this function on its failure path |
3822 | * and this function should be able to release pools which went through, | |
3823 | * successfully or not, init_worker_pool(). | |
3824 | * | |
3825 | * Should be called with wq_pool_mutex held. | |
3826 | */ | |
3827 | static void put_unbound_pool(struct worker_pool *pool) | |
226223ab | 3828 | { |
6ba94429 FW |
3829 | DECLARE_COMPLETION_ONSTACK(detach_completion); |
3830 | struct worker *worker; | |
9680540c | 3831 | LIST_HEAD(cull_list); |
e02b9312 | 3832 | |
6ba94429 | 3833 | lockdep_assert_held(&wq_pool_mutex); |
226223ab | 3834 | |
6ba94429 FW |
3835 | if (--pool->refcnt) |
3836 | return; | |
226223ab | 3837 | |
6ba94429 FW |
3838 | /* sanity checks */ |
3839 | if (WARN_ON(!(pool->cpu < 0)) || | |
3840 | WARN_ON(!list_empty(&pool->worklist))) | |
3841 | return; | |
226223ab | 3842 | |
6ba94429 FW |
3843 | /* release id and unhash */ |
3844 | if (pool->id >= 0) | |
3845 | idr_remove(&worker_pool_idr, pool->id); | |
3846 | hash_del(&pool->hash_node); | |
d55262c4 | 3847 | |
6ba94429 | 3848 | /* |
692b4825 TH |
3849 | * Become the manager and destroy all workers. This prevents |
3850 | * @pool's workers from blocking on attach_mutex. We're the last | |
3851 | * manager and @pool gets freed with the flag set. | |
9ab03be4 VS |
3852 | * |
3853 | * Having a concurrent manager is quite unlikely to happen as we can | |
3854 | * only get here with | |
3855 | * pwq->refcnt == pool->refcnt == 0 | |
3856 | * which implies no work queued to the pool, which implies no worker can | |
3857 | * become the manager. However a worker could have taken the role of | |
3858 | * manager before the refcnts dropped to 0, since maybe_create_worker() | |
3859 | * drops pool->lock | |
6ba94429 | 3860 | */ |
9ab03be4 VS |
3861 | while (true) { |
3862 | rcuwait_wait_event(&manager_wait, | |
3863 | !(pool->flags & POOL_MANAGER_ACTIVE), | |
3864 | TASK_UNINTERRUPTIBLE); | |
e02b9312 VS |
3865 | |
3866 | mutex_lock(&wq_pool_attach_mutex); | |
9ab03be4 VS |
3867 | raw_spin_lock_irq(&pool->lock); |
3868 | if (!(pool->flags & POOL_MANAGER_ACTIVE)) { | |
3869 | pool->flags |= POOL_MANAGER_ACTIVE; | |
3870 | break; | |
3871 | } | |
3872 | raw_spin_unlock_irq(&pool->lock); | |
e02b9312 | 3873 | mutex_unlock(&wq_pool_attach_mutex); |
9ab03be4 | 3874 | } |
692b4825 | 3875 | |
6ba94429 | 3876 | while ((worker = first_idle_worker(pool))) |
e02b9312 | 3877 | set_worker_dying(worker, &cull_list); |
6ba94429 | 3878 | WARN_ON(pool->nr_workers || pool->nr_idle); |
a9b8a985 | 3879 | raw_spin_unlock_irq(&pool->lock); |
d55262c4 | 3880 | |
e02b9312 VS |
3881 | wake_dying_workers(&cull_list); |
3882 | ||
3883 | if (!list_empty(&pool->workers) || !list_empty(&pool->dying_workers)) | |
6ba94429 | 3884 | pool->detach_completion = &detach_completion; |
1258fae7 | 3885 | mutex_unlock(&wq_pool_attach_mutex); |
226223ab | 3886 | |
6ba94429 FW |
3887 | if (pool->detach_completion) |
3888 | wait_for_completion(pool->detach_completion); | |
226223ab | 3889 | |
6ba94429 FW |
3890 | /* shut down the timers */ |
3891 | del_timer_sync(&pool->idle_timer); | |
3f959aa3 | 3892 | cancel_work_sync(&pool->idle_cull_work); |
6ba94429 | 3893 | del_timer_sync(&pool->mayday_timer); |
226223ab | 3894 | |
24acfb71 | 3895 | /* RCU protected to allow dereferences from get_work_pool() */ |
25b00775 | 3896 | call_rcu(&pool->rcu, rcu_free_pool); |
226223ab TH |
3897 | } |
3898 | ||
3899 | /** | |
6ba94429 FW |
3900 | * get_unbound_pool - get a worker_pool with the specified attributes |
3901 | * @attrs: the attributes of the worker_pool to get | |
226223ab | 3902 | * |
6ba94429 FW |
3903 | * Obtain a worker_pool which has the same attributes as @attrs, bump the |
3904 | * reference count and return it. If there already is a matching | |
3905 | * worker_pool, it will be used; otherwise, this function attempts to | |
3906 | * create a new one. | |
226223ab | 3907 | * |
6ba94429 | 3908 | * Should be called with wq_pool_mutex held. |
226223ab | 3909 | * |
6ba94429 FW |
3910 | * Return: On success, a worker_pool with the same attributes as @attrs. |
3911 | * On failure, %NULL. | |
226223ab | 3912 | */ |
6ba94429 | 3913 | static struct worker_pool *get_unbound_pool(const struct workqueue_attrs *attrs) |
226223ab | 3914 | { |
6ba94429 FW |
3915 | u32 hash = wqattrs_hash(attrs); |
3916 | struct worker_pool *pool; | |
fef59c9c TH |
3917 | int pod; |
3918 | int target_pod = NUMA_NO_NODE; | |
226223ab | 3919 | |
6ba94429 | 3920 | lockdep_assert_held(&wq_pool_mutex); |
226223ab | 3921 | |
6ba94429 FW |
3922 | /* do we already have a matching pool? */ |
3923 | hash_for_each_possible(unbound_pool_hash, pool, hash_node, hash) { | |
3924 | if (wqattrs_equal(pool->attrs, attrs)) { | |
3925 | pool->refcnt++; | |
3926 | return pool; | |
3927 | } | |
3928 | } | |
226223ab | 3929 | |
fef59c9c TH |
3930 | /* if cpumask is contained inside a pod, we belong to that pod */ |
3931 | if (wq_pod_enabled) { | |
3932 | for_each_node(pod) { | |
3933 | if (cpumask_subset(attrs->cpumask, wq_pod_cpus[pod])) { | |
3934 | target_pod = pod; | |
e2273584 XP |
3935 | break; |
3936 | } | |
3937 | } | |
3938 | } | |
3939 | ||
6ba94429 | 3940 | /* nope, create a new one */ |
fef59c9c | 3941 | pool = kzalloc_node(sizeof(*pool), GFP_KERNEL, target_pod); |
6ba94429 FW |
3942 | if (!pool || init_worker_pool(pool) < 0) |
3943 | goto fail; | |
3944 | ||
6ba94429 | 3945 | copy_workqueue_attrs(pool->attrs, attrs); |
fef59c9c | 3946 | pool->node = target_pod; |
226223ab TH |
3947 | |
3948 | /* | |
af73f5c9 | 3949 | * ordered isn't a worker_pool attribute, always clear it. See |
6ba94429 | 3950 | * 'struct workqueue_attrs' comments for detail. |
226223ab | 3951 | */ |
af73f5c9 | 3952 | pool->attrs->ordered = false; |
226223ab | 3953 | |
6ba94429 FW |
3954 | if (worker_pool_assign_id(pool) < 0) |
3955 | goto fail; | |
226223ab | 3956 | |
6ba94429 | 3957 | /* create and start the initial worker */ |
3347fa09 | 3958 | if (wq_online && !create_worker(pool)) |
6ba94429 | 3959 | goto fail; |
226223ab | 3960 | |
6ba94429 FW |
3961 | /* install */ |
3962 | hash_add(unbound_pool_hash, &pool->hash_node, hash); | |
226223ab | 3963 | |
6ba94429 FW |
3964 | return pool; |
3965 | fail: | |
3966 | if (pool) | |
3967 | put_unbound_pool(pool); | |
3968 | return NULL; | |
226223ab | 3969 | } |
226223ab | 3970 | |
6ba94429 | 3971 | static void rcu_free_pwq(struct rcu_head *rcu) |
7a4e344c | 3972 | { |
6ba94429 FW |
3973 | kmem_cache_free(pwq_cache, |
3974 | container_of(rcu, struct pool_workqueue, rcu)); | |
7a4e344c TH |
3975 | } |
3976 | ||
6ba94429 | 3977 | /* |
967b494e TH |
3978 | * Scheduled on pwq_release_worker by put_pwq() when an unbound pwq hits zero |
3979 | * refcnt and needs to be destroyed. | |
7a4e344c | 3980 | */ |
687a9aa5 | 3981 | static void pwq_release_workfn(struct kthread_work *work) |
7a4e344c | 3982 | { |
6ba94429 | 3983 | struct pool_workqueue *pwq = container_of(work, struct pool_workqueue, |
687a9aa5 | 3984 | release_work); |
6ba94429 FW |
3985 | struct workqueue_struct *wq = pwq->wq; |
3986 | struct worker_pool *pool = pwq->pool; | |
b42b0bdd | 3987 | bool is_last = false; |
7a4e344c | 3988 | |
b42b0bdd | 3989 | /* |
687a9aa5 | 3990 | * When @pwq is not linked, it doesn't hold any reference to the |
b42b0bdd YY |
3991 | * @wq, and @wq is invalid to access. |
3992 | */ | |
3993 | if (!list_empty(&pwq->pwqs_node)) { | |
b42b0bdd YY |
3994 | mutex_lock(&wq->mutex); |
3995 | list_del_rcu(&pwq->pwqs_node); | |
3996 | is_last = list_empty(&wq->pwqs); | |
3997 | mutex_unlock(&wq->mutex); | |
3998 | } | |
6ba94429 | 3999 | |
687a9aa5 TH |
4000 | if (wq->flags & WQ_UNBOUND) { |
4001 | mutex_lock(&wq_pool_mutex); | |
4002 | put_unbound_pool(pool); | |
4003 | mutex_unlock(&wq_pool_mutex); | |
4004 | } | |
6ba94429 | 4005 | |
25b00775 | 4006 | call_rcu(&pwq->rcu, rcu_free_pwq); |
7a4e344c | 4007 | |
2865a8fb | 4008 | /* |
6ba94429 FW |
4009 | * If we're the last pwq going away, @wq is already dead and no one |
4010 | * is gonna access it anymore. Schedule RCU free. | |
2865a8fb | 4011 | */ |
669de8bd BVA |
4012 | if (is_last) { |
4013 | wq_unregister_lockdep(wq); | |
25b00775 | 4014 | call_rcu(&wq->rcu, rcu_free_wq); |
669de8bd | 4015 | } |
29c91e99 TH |
4016 | } |
4017 | ||
7a4e344c | 4018 | /** |
6ba94429 FW |
4019 | * pwq_adjust_max_active - update a pwq's max_active to the current setting |
4020 | * @pwq: target pool_workqueue | |
d185af30 | 4021 | * |
6ba94429 | 4022 | * If @pwq isn't freezing, set @pwq->max_active to the associated |
f97a4a1a | 4023 | * workqueue's saved_max_active and activate inactive work items |
6ba94429 | 4024 | * accordingly. If @pwq is freezing, clear @pwq->max_active to zero. |
7a4e344c | 4025 | */ |
6ba94429 | 4026 | static void pwq_adjust_max_active(struct pool_workqueue *pwq) |
4e1a1f9a | 4027 | { |
6ba94429 FW |
4028 | struct workqueue_struct *wq = pwq->wq; |
4029 | bool freezable = wq->flags & WQ_FREEZABLE; | |
3347fa09 | 4030 | unsigned long flags; |
4e1a1f9a | 4031 | |
6ba94429 FW |
4032 | /* for @wq->saved_max_active */ |
4033 | lockdep_assert_held(&wq->mutex); | |
4e1a1f9a | 4034 | |
6ba94429 FW |
4035 | /* fast exit for non-freezable wqs */ |
4036 | if (!freezable && pwq->max_active == wq->saved_max_active) | |
4037 | return; | |
7a4e344c | 4038 | |
3347fa09 | 4039 | /* this function can be called during early boot w/ irq disabled */ |
a9b8a985 | 4040 | raw_spin_lock_irqsave(&pwq->pool->lock, flags); |
29c91e99 | 4041 | |
6ba94429 FW |
4042 | /* |
4043 | * During [un]freezing, the caller is responsible for ensuring that | |
4044 | * this function is called at least once after @workqueue_freezing | |
4045 | * is updated and visible. | |
4046 | */ | |
4047 | if (!freezable || !workqueue_freezing) { | |
01341fbd YY |
4048 | bool kick = false; |
4049 | ||
6ba94429 | 4050 | pwq->max_active = wq->saved_max_active; |
4e1a1f9a | 4051 | |
f97a4a1a | 4052 | while (!list_empty(&pwq->inactive_works) && |
01341fbd | 4053 | pwq->nr_active < pwq->max_active) { |
f97a4a1a | 4054 | pwq_activate_first_inactive(pwq); |
01341fbd YY |
4055 | kick = true; |
4056 | } | |
e2dca7ad | 4057 | |
6ba94429 FW |
4058 | /* |
4059 | * Need to kick a worker after thawed or an unbound wq's | |
01341fbd YY |
4060 | * max_active is bumped. In realtime scenarios, always kicking a |
4061 | * worker will cause interference on the isolated cpu cores, so | |
4062 | * let's kick iff work items were activated. | |
6ba94429 | 4063 | */ |
01341fbd YY |
4064 | if (kick) |
4065 | wake_up_worker(pwq->pool); | |
6ba94429 FW |
4066 | } else { |
4067 | pwq->max_active = 0; | |
4068 | } | |
e2dca7ad | 4069 | |
a9b8a985 | 4070 | raw_spin_unlock_irqrestore(&pwq->pool->lock, flags); |
e2dca7ad TH |
4071 | } |
4072 | ||
67dc8325 | 4073 | /* initialize newly allocated @pwq which is associated with @wq and @pool */ |
6ba94429 FW |
4074 | static void init_pwq(struct pool_workqueue *pwq, struct workqueue_struct *wq, |
4075 | struct worker_pool *pool) | |
29c91e99 | 4076 | { |
6ba94429 | 4077 | BUG_ON((unsigned long)pwq & WORK_STRUCT_FLAG_MASK); |
29c91e99 | 4078 | |
6ba94429 FW |
4079 | memset(pwq, 0, sizeof(*pwq)); |
4080 | ||
4081 | pwq->pool = pool; | |
4082 | pwq->wq = wq; | |
4083 | pwq->flush_color = -1; | |
4084 | pwq->refcnt = 1; | |
f97a4a1a | 4085 | INIT_LIST_HEAD(&pwq->inactive_works); |
6ba94429 FW |
4086 | INIT_LIST_HEAD(&pwq->pwqs_node); |
4087 | INIT_LIST_HEAD(&pwq->mayday_node); | |
687a9aa5 | 4088 | kthread_init_work(&pwq->release_work, pwq_release_workfn); |
29c91e99 TH |
4089 | } |
4090 | ||
6ba94429 FW |
4091 | /* sync @pwq with the current state of its associated wq and link it */ |
4092 | static void link_pwq(struct pool_workqueue *pwq) | |
29c91e99 | 4093 | { |
6ba94429 | 4094 | struct workqueue_struct *wq = pwq->wq; |
29c91e99 | 4095 | |
6ba94429 | 4096 | lockdep_assert_held(&wq->mutex); |
a892cacc | 4097 | |
6ba94429 FW |
4098 | /* may be called multiple times, ignore if already linked */ |
4099 | if (!list_empty(&pwq->pwqs_node)) | |
29c91e99 | 4100 | return; |
29c91e99 | 4101 | |
6ba94429 FW |
4102 | /* set the matching work_color */ |
4103 | pwq->work_color = wq->work_color; | |
29c91e99 | 4104 | |
6ba94429 FW |
4105 | /* sync max_active to the current setting */ |
4106 | pwq_adjust_max_active(pwq); | |
29c91e99 | 4107 | |
6ba94429 FW |
4108 | /* link in @pwq */ |
4109 | list_add_rcu(&pwq->pwqs_node, &wq->pwqs); | |
4110 | } | |
29c91e99 | 4111 | |
6ba94429 FW |
4112 | /* obtain a pool matching @attr and create a pwq associating the pool and @wq */ |
4113 | static struct pool_workqueue *alloc_unbound_pwq(struct workqueue_struct *wq, | |
4114 | const struct workqueue_attrs *attrs) | |
4115 | { | |
4116 | struct worker_pool *pool; | |
4117 | struct pool_workqueue *pwq; | |
60f5a4bc | 4118 | |
6ba94429 | 4119 | lockdep_assert_held(&wq_pool_mutex); |
60f5a4bc | 4120 | |
6ba94429 FW |
4121 | pool = get_unbound_pool(attrs); |
4122 | if (!pool) | |
4123 | return NULL; | |
60f5a4bc | 4124 | |
6ba94429 FW |
4125 | pwq = kmem_cache_alloc_node(pwq_cache, GFP_KERNEL, pool->node); |
4126 | if (!pwq) { | |
4127 | put_unbound_pool(pool); | |
4128 | return NULL; | |
4129 | } | |
29c91e99 | 4130 | |
6ba94429 FW |
4131 | init_pwq(pwq, wq, pool); |
4132 | return pwq; | |
4133 | } | |
29c91e99 | 4134 | |
29c91e99 | 4135 | /** |
fef59c9c | 4136 | * wq_calc_pod_cpumask - calculate a wq_attrs' cpumask for a pod |
042f7df1 | 4137 | * @attrs: the wq_attrs of the default pwq of the target workqueue |
fef59c9c | 4138 | * @pod: the target CPU pod |
6ba94429 FW |
4139 | * @cpu_going_down: if >= 0, the CPU to consider as offline |
4140 | * @cpumask: outarg, the resulting cpumask | |
29c91e99 | 4141 | * |
fef59c9c TH |
4142 | * Calculate the cpumask a workqueue with @attrs should use on @pod. If |
4143 | * @cpu_going_down is >= 0, that cpu is considered offline during calculation. | |
4144 | * The result is stored in @cpumask. | |
a892cacc | 4145 | * |
fef59c9c TH |
4146 | * If pod affinity is not enabled, @attrs->cpumask is always used. If enabled |
4147 | * and @pod has online CPUs requested by @attrs, the returned cpumask is the | |
4148 | * intersection of the possible CPUs of @pod and @attrs->cpumask. | |
d185af30 | 4149 | * |
fef59c9c | 4150 | * The caller is responsible for ensuring that the cpumask of @pod stays stable. |
29c91e99 | 4151 | */ |
fef59c9c | 4152 | static void wq_calc_pod_cpumask(const struct workqueue_attrs *attrs, int pod, |
6ba94429 | 4153 | int cpu_going_down, cpumask_t *cpumask) |
29c91e99 | 4154 | { |
fef59c9c | 4155 | if (!wq_pod_enabled || attrs->ordered) |
6ba94429 | 4156 | goto use_dfl; |
29c91e99 | 4157 | |
fef59c9c TH |
4158 | /* does @pod have any online CPUs @attrs wants? */ |
4159 | cpumask_and(cpumask, cpumask_of_node(pod), attrs->cpumask); | |
6ba94429 FW |
4160 | if (cpu_going_down >= 0) |
4161 | cpumask_clear_cpu(cpu_going_down, cpumask); | |
29c91e99 | 4162 | |
6ba94429 FW |
4163 | if (cpumask_empty(cpumask)) |
4164 | goto use_dfl; | |
4c16bd32 | 4165 | |
fef59c9c TH |
4166 | /* yeap, return possible CPUs in @pod that @attrs wants */ |
4167 | cpumask_and(cpumask, attrs->cpumask, wq_pod_cpus[pod]); | |
1ad0f0a7 | 4168 | |
636b927e | 4169 | if (cpumask_empty(cpumask)) |
1ad0f0a7 MB |
4170 | pr_warn_once("WARNING: workqueue cpumask: online intersect > " |
4171 | "possible intersect\n"); | |
636b927e | 4172 | return; |
4c16bd32 TH |
4173 | |
4174 | use_dfl: | |
4175 | cpumask_copy(cpumask, attrs->cpumask); | |
4c16bd32 TH |
4176 | } |
4177 | ||
636b927e TH |
4178 | /* install @pwq into @wq's cpu_pwq and return the old pwq */ |
4179 | static struct pool_workqueue *install_unbound_pwq(struct workqueue_struct *wq, | |
4180 | int cpu, struct pool_workqueue *pwq) | |
1befcf30 TH |
4181 | { |
4182 | struct pool_workqueue *old_pwq; | |
4183 | ||
5b95e1af | 4184 | lockdep_assert_held(&wq_pool_mutex); |
1befcf30 TH |
4185 | lockdep_assert_held(&wq->mutex); |
4186 | ||
4187 | /* link_pwq() can handle duplicate calls */ | |
4188 | link_pwq(pwq); | |
4189 | ||
636b927e TH |
4190 | old_pwq = rcu_access_pointer(*per_cpu_ptr(wq->cpu_pwq, cpu)); |
4191 | rcu_assign_pointer(*per_cpu_ptr(wq->cpu_pwq, cpu), pwq); | |
1befcf30 TH |
4192 | return old_pwq; |
4193 | } | |
4194 | ||
2d5f0764 LJ |
4195 | /* context to store the prepared attrs & pwqs before applying */ |
4196 | struct apply_wqattrs_ctx { | |
4197 | struct workqueue_struct *wq; /* target workqueue */ | |
4198 | struct workqueue_attrs *attrs; /* attrs to apply */ | |
042f7df1 | 4199 | struct list_head list; /* queued for batching commit */ |
2d5f0764 LJ |
4200 | struct pool_workqueue *dfl_pwq; |
4201 | struct pool_workqueue *pwq_tbl[]; | |
4202 | }; | |
4203 | ||
4204 | /* free the resources after success or abort */ | |
4205 | static void apply_wqattrs_cleanup(struct apply_wqattrs_ctx *ctx) | |
4206 | { | |
4207 | if (ctx) { | |
636b927e | 4208 | int cpu; |
2d5f0764 | 4209 | |
636b927e TH |
4210 | for_each_possible_cpu(cpu) |
4211 | put_pwq_unlocked(ctx->pwq_tbl[cpu]); | |
2d5f0764 LJ |
4212 | put_pwq_unlocked(ctx->dfl_pwq); |
4213 | ||
4214 | free_workqueue_attrs(ctx->attrs); | |
4215 | ||
4216 | kfree(ctx); | |
4217 | } | |
4218 | } | |
4219 | ||
4220 | /* allocate the attrs and pwqs for later installation */ | |
4221 | static struct apply_wqattrs_ctx * | |
4222 | apply_wqattrs_prepare(struct workqueue_struct *wq, | |
99c621ef LJ |
4223 | const struct workqueue_attrs *attrs, |
4224 | const cpumask_var_t unbound_cpumask) | |
9e8cd2f5 | 4225 | { |
2d5f0764 | 4226 | struct apply_wqattrs_ctx *ctx; |
4c16bd32 | 4227 | struct workqueue_attrs *new_attrs, *tmp_attrs; |
636b927e | 4228 | int cpu; |
9e8cd2f5 | 4229 | |
2d5f0764 | 4230 | lockdep_assert_held(&wq_pool_mutex); |
9e8cd2f5 | 4231 | |
636b927e | 4232 | ctx = kzalloc(struct_size(ctx, pwq_tbl, nr_cpu_ids), GFP_KERNEL); |
8719dcea | 4233 | |
be69d00d TG |
4234 | new_attrs = alloc_workqueue_attrs(); |
4235 | tmp_attrs = alloc_workqueue_attrs(); | |
2d5f0764 LJ |
4236 | if (!ctx || !new_attrs || !tmp_attrs) |
4237 | goto out_free; | |
13e2e556 | 4238 | |
4c16bd32 TH |
4239 | /* |
4240 | * If something goes wrong during CPU up/down, we'll fall back to | |
4241 | * the default pwq covering whole @attrs->cpumask. Always create | |
4242 | * it even if we don't use it immediately. | |
4243 | */ | |
0f36ee24 TH |
4244 | copy_workqueue_attrs(new_attrs, attrs); |
4245 | wqattrs_actualize_cpumask(new_attrs, unbound_cpumask); | |
2d5f0764 LJ |
4246 | ctx->dfl_pwq = alloc_unbound_pwq(wq, new_attrs); |
4247 | if (!ctx->dfl_pwq) | |
4248 | goto out_free; | |
4c16bd32 | 4249 | |
0f36ee24 TH |
4250 | /* |
4251 | * We may create multiple pwqs with differing cpumasks. Make a copy of | |
4252 | * @new_attrs which will be modified and used to obtain pools. | |
4253 | */ | |
4254 | copy_workqueue_attrs(tmp_attrs, new_attrs); | |
4255 | ||
636b927e | 4256 | for_each_possible_cpu(cpu) { |
af73f5c9 | 4257 | if (new_attrs->ordered) { |
2d5f0764 | 4258 | ctx->dfl_pwq->refcnt++; |
636b927e TH |
4259 | ctx->pwq_tbl[cpu] = ctx->dfl_pwq; |
4260 | } else { | |
fef59c9c TH |
4261 | wq_calc_pod_cpumask(new_attrs, cpu_to_node(cpu), -1, |
4262 | tmp_attrs->cpumask); | |
636b927e TH |
4263 | ctx->pwq_tbl[cpu] = alloc_unbound_pwq(wq, tmp_attrs); |
4264 | if (!ctx->pwq_tbl[cpu]) | |
4265 | goto out_free; | |
4c16bd32 TH |
4266 | } |
4267 | } | |
4268 | ||
042f7df1 LJ |
4269 | /* save the user configured attrs and sanitize it. */ |
4270 | copy_workqueue_attrs(new_attrs, attrs); | |
4271 | cpumask_and(new_attrs->cpumask, new_attrs->cpumask, cpu_possible_mask); | |
2d5f0764 | 4272 | ctx->attrs = new_attrs; |
042f7df1 | 4273 | |
2d5f0764 LJ |
4274 | ctx->wq = wq; |
4275 | free_workqueue_attrs(tmp_attrs); | |
4276 | return ctx; | |
4277 | ||
4278 | out_free: | |
4279 | free_workqueue_attrs(tmp_attrs); | |
4280 | free_workqueue_attrs(new_attrs); | |
4281 | apply_wqattrs_cleanup(ctx); | |
4282 | return NULL; | |
4283 | } | |
4284 | ||
4285 | /* set attrs and install prepared pwqs, @ctx points to old pwqs on return */ | |
4286 | static void apply_wqattrs_commit(struct apply_wqattrs_ctx *ctx) | |
4287 | { | |
636b927e | 4288 | int cpu; |
9e8cd2f5 | 4289 | |
4c16bd32 | 4290 | /* all pwqs have been created successfully, let's install'em */ |
2d5f0764 | 4291 | mutex_lock(&ctx->wq->mutex); |
a892cacc | 4292 | |
2d5f0764 | 4293 | copy_workqueue_attrs(ctx->wq->unbound_attrs, ctx->attrs); |
4c16bd32 TH |
4294 | |
4295 | /* save the previous pwq and install the new one */ | |
636b927e TH |
4296 | for_each_possible_cpu(cpu) |
4297 | ctx->pwq_tbl[cpu] = install_unbound_pwq(ctx->wq, cpu, | |
4298 | ctx->pwq_tbl[cpu]); | |
4c16bd32 TH |
4299 | |
4300 | /* @dfl_pwq might not have been used, ensure it's linked */ | |
2d5f0764 LJ |
4301 | link_pwq(ctx->dfl_pwq); |
4302 | swap(ctx->wq->dfl_pwq, ctx->dfl_pwq); | |
f147f29e | 4303 | |
2d5f0764 LJ |
4304 | mutex_unlock(&ctx->wq->mutex); |
4305 | } | |
9e8cd2f5 | 4306 | |
a0111cf6 LJ |
4307 | static void apply_wqattrs_lock(void) |
4308 | { | |
4309 | /* CPUs should stay stable across pwq creations and installations */ | |
ffd8bea8 | 4310 | cpus_read_lock(); |
a0111cf6 LJ |
4311 | mutex_lock(&wq_pool_mutex); |
4312 | } | |
4313 | ||
4314 | static void apply_wqattrs_unlock(void) | |
4315 | { | |
4316 | mutex_unlock(&wq_pool_mutex); | |
ffd8bea8 | 4317 | cpus_read_unlock(); |
a0111cf6 LJ |
4318 | } |
4319 | ||
4320 | static int apply_workqueue_attrs_locked(struct workqueue_struct *wq, | |
4321 | const struct workqueue_attrs *attrs) | |
2d5f0764 LJ |
4322 | { |
4323 | struct apply_wqattrs_ctx *ctx; | |
4c16bd32 | 4324 | |
2d5f0764 LJ |
4325 | /* only unbound workqueues can change attributes */ |
4326 | if (WARN_ON(!(wq->flags & WQ_UNBOUND))) | |
4327 | return -EINVAL; | |
13e2e556 | 4328 | |
2d5f0764 | 4329 | /* creating multiple pwqs breaks ordering guarantee */ |
0a94efb5 TH |
4330 | if (!list_empty(&wq->pwqs)) { |
4331 | if (WARN_ON(wq->flags & __WQ_ORDERED_EXPLICIT)) | |
4332 | return -EINVAL; | |
4333 | ||
4334 | wq->flags &= ~__WQ_ORDERED; | |
4335 | } | |
2d5f0764 | 4336 | |
99c621ef | 4337 | ctx = apply_wqattrs_prepare(wq, attrs, wq_unbound_cpumask); |
6201171e | 4338 | if (!ctx) |
4339 | return -ENOMEM; | |
2d5f0764 LJ |
4340 | |
4341 | /* the ctx has been prepared successfully, let's commit it */ | |
6201171e | 4342 | apply_wqattrs_commit(ctx); |
2d5f0764 LJ |
4343 | apply_wqattrs_cleanup(ctx); |
4344 | ||
6201171e | 4345 | return 0; |
9e8cd2f5 TH |
4346 | } |
4347 | ||
a0111cf6 LJ |
4348 | /** |
4349 | * apply_workqueue_attrs - apply new workqueue_attrs to an unbound workqueue | |
4350 | * @wq: the target workqueue | |
4351 | * @attrs: the workqueue_attrs to apply, allocated with alloc_workqueue_attrs() | |
4352 | * | |
fef59c9c TH |
4353 | * Apply @attrs to an unbound workqueue @wq. Unless disabled, this function maps |
4354 | * a separate pwq to each CPU pod with possibles CPUs in @attrs->cpumask so that | |
4355 | * work items are affine to the pod it was issued on. Older pwqs are released as | |
4356 | * in-flight work items finish. Note that a work item which repeatedly requeues | |
4357 | * itself back-to-back will stay on its current pwq. | |
a0111cf6 LJ |
4358 | * |
4359 | * Performs GFP_KERNEL allocations. | |
4360 | * | |
ffd8bea8 | 4361 | * Assumes caller has CPU hotplug read exclusion, i.e. cpus_read_lock(). |
509b3204 | 4362 | * |
a0111cf6 LJ |
4363 | * Return: 0 on success and -errno on failure. |
4364 | */ | |
513c98d0 | 4365 | int apply_workqueue_attrs(struct workqueue_struct *wq, |
a0111cf6 LJ |
4366 | const struct workqueue_attrs *attrs) |
4367 | { | |
4368 | int ret; | |
4369 | ||
509b3204 DJ |
4370 | lockdep_assert_cpus_held(); |
4371 | ||
4372 | mutex_lock(&wq_pool_mutex); | |
a0111cf6 | 4373 | ret = apply_workqueue_attrs_locked(wq, attrs); |
509b3204 | 4374 | mutex_unlock(&wq_pool_mutex); |
a0111cf6 LJ |
4375 | |
4376 | return ret; | |
4377 | } | |
4378 | ||
4c16bd32 | 4379 | /** |
fef59c9c | 4380 | * wq_update_pod - update pod affinity of a wq for CPU hot[un]plug |
4c16bd32 | 4381 | * @wq: the target workqueue |
4cbfd3de TH |
4382 | * @cpu: the CPU to update pool association for |
4383 | * @hotplug_cpu: the CPU coming up or going down | |
4c16bd32 TH |
4384 | * @online: whether @cpu is coming up or going down |
4385 | * | |
4386 | * This function is to be called from %CPU_DOWN_PREPARE, %CPU_ONLINE and | |
fef59c9c | 4387 | * %CPU_DOWN_FAILED. @cpu is being hot[un]plugged, update pod affinity of |
4c16bd32 TH |
4388 | * @wq accordingly. |
4389 | * | |
fef59c9c TH |
4390 | * |
4391 | * If pod affinity can't be adjusted due to memory allocation failure, it falls | |
4392 | * back to @wq->dfl_pwq which may not be optimal but is always correct. | |
4393 | * | |
4394 | * Note that when the last allowed CPU of a pod goes offline for a workqueue | |
4395 | * with a cpumask spanning multiple pods, the workers which were already | |
4396 | * executing the work items for the workqueue will lose their CPU affinity and | |
4397 | * may execute on any CPU. This is similar to how per-cpu workqueues behave on | |
4398 | * CPU_DOWN. If a workqueue user wants strict affinity, it's the user's | |
4399 | * responsibility to flush the work item from CPU_DOWN_PREPARE. | |
4c16bd32 | 4400 | */ |
fef59c9c TH |
4401 | static void wq_update_pod(struct workqueue_struct *wq, int cpu, |
4402 | int hotplug_cpu, bool online) | |
4c16bd32 | 4403 | { |
fef59c9c | 4404 | int pod = cpu_to_node(cpu); |
4cbfd3de | 4405 | int off_cpu = online ? -1 : hotplug_cpu; |
4c16bd32 TH |
4406 | struct pool_workqueue *old_pwq = NULL, *pwq; |
4407 | struct workqueue_attrs *target_attrs; | |
4408 | cpumask_t *cpumask; | |
4409 | ||
4410 | lockdep_assert_held(&wq_pool_mutex); | |
4411 | ||
fef59c9c | 4412 | if (!wq_pod_enabled || !(wq->flags & WQ_UNBOUND) || |
af73f5c9 | 4413 | wq->unbound_attrs->ordered) |
4c16bd32 TH |
4414 | return; |
4415 | ||
4416 | /* | |
4417 | * We don't wanna alloc/free wq_attrs for each wq for each CPU. | |
4418 | * Let's use a preallocated one. The following buf is protected by | |
4419 | * CPU hotplug exclusion. | |
4420 | */ | |
fef59c9c | 4421 | target_attrs = wq_update_pod_attrs_buf; |
0f36ee24 | 4422 | cpumask = wq_update_pod_cpumask_buf; |
4c16bd32 | 4423 | |
4c16bd32 | 4424 | copy_workqueue_attrs(target_attrs, wq->unbound_attrs); |
0f36ee24 | 4425 | wqattrs_actualize_cpumask(target_attrs, wq_unbound_cpumask); |
4c16bd32 | 4426 | |
636b927e | 4427 | /* nothing to do if the target cpumask matches the current pwq */ |
0f36ee24 | 4428 | wq_calc_pod_cpumask(target_attrs, pod, off_cpu, cpumask); |
636b927e TH |
4429 | pwq = rcu_dereference_protected(*per_cpu_ptr(wq->cpu_pwq, cpu), |
4430 | lockdep_is_held(&wq_pool_mutex)); | |
4431 | if (cpumask_equal(cpumask, pwq->pool->attrs->cpumask)) | |
4432 | return; | |
4c16bd32 | 4433 | |
4c16bd32 | 4434 | /* create a new pwq */ |
0f36ee24 | 4435 | cpumask_copy(target_attrs->cpumask, cpumask); |
4c16bd32 TH |
4436 | pwq = alloc_unbound_pwq(wq, target_attrs); |
4437 | if (!pwq) { | |
fef59c9c | 4438 | pr_warn("workqueue: allocation failed while updating CPU pod affinity of \"%s\"\n", |
2d916033 | 4439 | wq->name); |
77f300b1 | 4440 | goto use_dfl_pwq; |
4c16bd32 TH |
4441 | } |
4442 | ||
f7142ed4 | 4443 | /* Install the new pwq. */ |
4c16bd32 | 4444 | mutex_lock(&wq->mutex); |
636b927e | 4445 | old_pwq = install_unbound_pwq(wq, cpu, pwq); |
4c16bd32 TH |
4446 | goto out_unlock; |
4447 | ||
4448 | use_dfl_pwq: | |
f7142ed4 | 4449 | mutex_lock(&wq->mutex); |
a9b8a985 | 4450 | raw_spin_lock_irq(&wq->dfl_pwq->pool->lock); |
4c16bd32 | 4451 | get_pwq(wq->dfl_pwq); |
a9b8a985 | 4452 | raw_spin_unlock_irq(&wq->dfl_pwq->pool->lock); |
636b927e | 4453 | old_pwq = install_unbound_pwq(wq, cpu, wq->dfl_pwq); |
4c16bd32 TH |
4454 | out_unlock: |
4455 | mutex_unlock(&wq->mutex); | |
4456 | put_pwq_unlocked(old_pwq); | |
4457 | } | |
4458 | ||
30cdf249 | 4459 | static int alloc_and_link_pwqs(struct workqueue_struct *wq) |
0f900049 | 4460 | { |
49e3cf44 | 4461 | bool highpri = wq->flags & WQ_HIGHPRI; |
8a2b7538 | 4462 | int cpu, ret; |
30cdf249 | 4463 | |
636b927e TH |
4464 | wq->cpu_pwq = alloc_percpu(struct pool_workqueue *); |
4465 | if (!wq->cpu_pwq) | |
4466 | goto enomem; | |
30cdf249 | 4467 | |
636b927e | 4468 | if (!(wq->flags & WQ_UNBOUND)) { |
30cdf249 | 4469 | for_each_possible_cpu(cpu) { |
687a9aa5 | 4470 | struct pool_workqueue **pwq_p = |
ee1ceef7 | 4471 | per_cpu_ptr(wq->cpu_pwq, cpu); |
687a9aa5 TH |
4472 | struct worker_pool *pool = |
4473 | &(per_cpu_ptr(cpu_worker_pools, cpu)[highpri]); | |
4474 | ||
4475 | *pwq_p = kmem_cache_alloc_node(pwq_cache, GFP_KERNEL, | |
4476 | pool->node); | |
4477 | if (!*pwq_p) | |
4478 | goto enomem; | |
f3421797 | 4479 | |
687a9aa5 | 4480 | init_pwq(*pwq_p, wq, pool); |
f147f29e TH |
4481 | |
4482 | mutex_lock(&wq->mutex); | |
687a9aa5 | 4483 | link_pwq(*pwq_p); |
f147f29e | 4484 | mutex_unlock(&wq->mutex); |
30cdf249 | 4485 | } |
9e8cd2f5 | 4486 | return 0; |
509b3204 DJ |
4487 | } |
4488 | ||
ffd8bea8 | 4489 | cpus_read_lock(); |
509b3204 | 4490 | if (wq->flags & __WQ_ORDERED) { |
8a2b7538 TH |
4491 | ret = apply_workqueue_attrs(wq, ordered_wq_attrs[highpri]); |
4492 | /* there should only be single pwq for ordering guarantee */ | |
4493 | WARN(!ret && (wq->pwqs.next != &wq->dfl_pwq->pwqs_node || | |
4494 | wq->pwqs.prev != &wq->dfl_pwq->pwqs_node), | |
4495 | "ordering guarantee broken for workqueue %s\n", wq->name); | |
30cdf249 | 4496 | } else { |
509b3204 | 4497 | ret = apply_workqueue_attrs(wq, unbound_std_wq_attrs[highpri]); |
30cdf249 | 4498 | } |
ffd8bea8 | 4499 | cpus_read_unlock(); |
509b3204 DJ |
4500 | |
4501 | return ret; | |
687a9aa5 TH |
4502 | |
4503 | enomem: | |
4504 | if (wq->cpu_pwq) { | |
4505 | for_each_possible_cpu(cpu) | |
4506 | kfree(*per_cpu_ptr(wq->cpu_pwq, cpu)); | |
4507 | free_percpu(wq->cpu_pwq); | |
4508 | wq->cpu_pwq = NULL; | |
4509 | } | |
4510 | return -ENOMEM; | |
0f900049 TH |
4511 | } |
4512 | ||
f3421797 TH |
4513 | static int wq_clamp_max_active(int max_active, unsigned int flags, |
4514 | const char *name) | |
b71ab8c2 | 4515 | { |
636b927e | 4516 | if (max_active < 1 || max_active > WQ_MAX_ACTIVE) |
044c782c | 4517 | pr_warn("workqueue: max_active %d requested for %s is out of range, clamping between %d and %d\n", |
636b927e | 4518 | max_active, name, 1, WQ_MAX_ACTIVE); |
b71ab8c2 | 4519 | |
636b927e | 4520 | return clamp_val(max_active, 1, WQ_MAX_ACTIVE); |
b71ab8c2 TH |
4521 | } |
4522 | ||
983c7515 TH |
4523 | /* |
4524 | * Workqueues which may be used during memory reclaim should have a rescuer | |
4525 | * to guarantee forward progress. | |
4526 | */ | |
4527 | static int init_rescuer(struct workqueue_struct *wq) | |
4528 | { | |
4529 | struct worker *rescuer; | |
b92b36ea | 4530 | int ret; |
983c7515 TH |
4531 | |
4532 | if (!(wq->flags & WQ_MEM_RECLAIM)) | |
4533 | return 0; | |
4534 | ||
4535 | rescuer = alloc_worker(NUMA_NO_NODE); | |
4c0736a7 PM |
4536 | if (!rescuer) { |
4537 | pr_err("workqueue: Failed to allocate a rescuer for wq \"%s\"\n", | |
4538 | wq->name); | |
983c7515 | 4539 | return -ENOMEM; |
4c0736a7 | 4540 | } |
983c7515 TH |
4541 | |
4542 | rescuer->rescue_wq = wq; | |
4543 | rescuer->task = kthread_create(rescuer_thread, rescuer, "%s", wq->name); | |
f187b697 | 4544 | if (IS_ERR(rescuer->task)) { |
b92b36ea | 4545 | ret = PTR_ERR(rescuer->task); |
4c0736a7 PM |
4546 | pr_err("workqueue: Failed to create a rescuer kthread for wq \"%s\": %pe", |
4547 | wq->name, ERR_PTR(ret)); | |
983c7515 | 4548 | kfree(rescuer); |
b92b36ea | 4549 | return ret; |
983c7515 TH |
4550 | } |
4551 | ||
4552 | wq->rescuer = rescuer; | |
4553 | kthread_bind_mask(rescuer->task, cpu_possible_mask); | |
4554 | wake_up_process(rescuer->task); | |
4555 | ||
4556 | return 0; | |
4557 | } | |
4558 | ||
a2775bbc | 4559 | __printf(1, 4) |
669de8bd BVA |
4560 | struct workqueue_struct *alloc_workqueue(const char *fmt, |
4561 | unsigned int flags, | |
4562 | int max_active, ...) | |
1da177e4 | 4563 | { |
ecf6881f | 4564 | va_list args; |
1da177e4 | 4565 | struct workqueue_struct *wq; |
49e3cf44 | 4566 | struct pool_workqueue *pwq; |
b196be89 | 4567 | |
5c0338c6 | 4568 | /* |
fef59c9c TH |
4569 | * Unbound && max_active == 1 used to imply ordered, which is no longer |
4570 | * the case on many machines due to per-pod pools. While | |
5c0338c6 | 4571 | * alloc_ordered_workqueue() is the right way to create an ordered |
fef59c9c | 4572 | * workqueue, keep the previous behavior to avoid subtle breakages. |
5c0338c6 TH |
4573 | */ |
4574 | if ((flags & WQ_UNBOUND) && max_active == 1) | |
4575 | flags |= __WQ_ORDERED; | |
4576 | ||
cee22a15 VK |
4577 | /* see the comment above the definition of WQ_POWER_EFFICIENT */ |
4578 | if ((flags & WQ_POWER_EFFICIENT) && wq_power_efficient) | |
4579 | flags |= WQ_UNBOUND; | |
4580 | ||
ecf6881f | 4581 | /* allocate wq and format name */ |
636b927e | 4582 | wq = kzalloc(sizeof(*wq), GFP_KERNEL); |
b196be89 | 4583 | if (!wq) |
d2c1d404 | 4584 | return NULL; |
b196be89 | 4585 | |
6029a918 | 4586 | if (flags & WQ_UNBOUND) { |
be69d00d | 4587 | wq->unbound_attrs = alloc_workqueue_attrs(); |
6029a918 TH |
4588 | if (!wq->unbound_attrs) |
4589 | goto err_free_wq; | |
4590 | } | |
4591 | ||
669de8bd | 4592 | va_start(args, max_active); |
ecf6881f | 4593 | vsnprintf(wq->name, sizeof(wq->name), fmt, args); |
b196be89 | 4594 | va_end(args); |
1da177e4 | 4595 | |
d320c038 | 4596 | max_active = max_active ?: WQ_DFL_ACTIVE; |
b196be89 | 4597 | max_active = wq_clamp_max_active(max_active, flags, wq->name); |
3af24433 | 4598 | |
b196be89 | 4599 | /* init wq */ |
97e37d7b | 4600 | wq->flags = flags; |
a0a1a5fd | 4601 | wq->saved_max_active = max_active; |
3c25a55d | 4602 | mutex_init(&wq->mutex); |
112202d9 | 4603 | atomic_set(&wq->nr_pwqs_to_flush, 0); |
30cdf249 | 4604 | INIT_LIST_HEAD(&wq->pwqs); |
73f53c4a TH |
4605 | INIT_LIST_HEAD(&wq->flusher_queue); |
4606 | INIT_LIST_HEAD(&wq->flusher_overflow); | |
493a1724 | 4607 | INIT_LIST_HEAD(&wq->maydays); |
502ca9d8 | 4608 | |
669de8bd | 4609 | wq_init_lockdep(wq); |
cce1a165 | 4610 | INIT_LIST_HEAD(&wq->list); |
3af24433 | 4611 | |
30cdf249 | 4612 | if (alloc_and_link_pwqs(wq) < 0) |
82efcab3 | 4613 | goto err_unreg_lockdep; |
1537663f | 4614 | |
40c17f75 | 4615 | if (wq_online && init_rescuer(wq) < 0) |
983c7515 | 4616 | goto err_destroy; |
3af24433 | 4617 | |
226223ab TH |
4618 | if ((wq->flags & WQ_SYSFS) && workqueue_sysfs_register(wq)) |
4619 | goto err_destroy; | |
4620 | ||
a0a1a5fd | 4621 | /* |
68e13a67 LJ |
4622 | * wq_pool_mutex protects global freeze state and workqueues list. |
4623 | * Grab it, adjust max_active and add the new @wq to workqueues | |
4624 | * list. | |
a0a1a5fd | 4625 | */ |
68e13a67 | 4626 | mutex_lock(&wq_pool_mutex); |
a0a1a5fd | 4627 | |
a357fc03 | 4628 | mutex_lock(&wq->mutex); |
699ce097 TH |
4629 | for_each_pwq(pwq, wq) |
4630 | pwq_adjust_max_active(pwq); | |
a357fc03 | 4631 | mutex_unlock(&wq->mutex); |
a0a1a5fd | 4632 | |
e2dca7ad | 4633 | list_add_tail_rcu(&wq->list, &workqueues); |
a0a1a5fd | 4634 | |
68e13a67 | 4635 | mutex_unlock(&wq_pool_mutex); |
1537663f | 4636 | |
3af24433 | 4637 | return wq; |
d2c1d404 | 4638 | |
82efcab3 | 4639 | err_unreg_lockdep: |
009bb421 BVA |
4640 | wq_unregister_lockdep(wq); |
4641 | wq_free_lockdep(wq); | |
82efcab3 | 4642 | err_free_wq: |
6029a918 | 4643 | free_workqueue_attrs(wq->unbound_attrs); |
d2c1d404 TH |
4644 | kfree(wq); |
4645 | return NULL; | |
4646 | err_destroy: | |
4647 | destroy_workqueue(wq); | |
4690c4ab | 4648 | return NULL; |
3af24433 | 4649 | } |
669de8bd | 4650 | EXPORT_SYMBOL_GPL(alloc_workqueue); |
1da177e4 | 4651 | |
c29eb853 TH |
4652 | static bool pwq_busy(struct pool_workqueue *pwq) |
4653 | { | |
4654 | int i; | |
4655 | ||
4656 | for (i = 0; i < WORK_NR_COLORS; i++) | |
4657 | if (pwq->nr_in_flight[i]) | |
4658 | return true; | |
4659 | ||
4660 | if ((pwq != pwq->wq->dfl_pwq) && (pwq->refcnt > 1)) | |
4661 | return true; | |
f97a4a1a | 4662 | if (pwq->nr_active || !list_empty(&pwq->inactive_works)) |
c29eb853 TH |
4663 | return true; |
4664 | ||
4665 | return false; | |
4666 | } | |
4667 | ||
3af24433 ON |
4668 | /** |
4669 | * destroy_workqueue - safely terminate a workqueue | |
4670 | * @wq: target workqueue | |
4671 | * | |
4672 | * Safely destroy a workqueue. All work currently pending will be done first. | |
4673 | */ | |
4674 | void destroy_workqueue(struct workqueue_struct *wq) | |
4675 | { | |
49e3cf44 | 4676 | struct pool_workqueue *pwq; |
636b927e | 4677 | int cpu; |
3af24433 | 4678 | |
def98c84 TH |
4679 | /* |
4680 | * Remove it from sysfs first so that sanity check failure doesn't | |
4681 | * lead to sysfs name conflicts. | |
4682 | */ | |
4683 | workqueue_sysfs_unregister(wq); | |
4684 | ||
33e3f0a3 RC |
4685 | /* mark the workqueue destruction is in progress */ |
4686 | mutex_lock(&wq->mutex); | |
4687 | wq->flags |= __WQ_DESTROYING; | |
4688 | mutex_unlock(&wq->mutex); | |
4689 | ||
9c5a2ba7 TH |
4690 | /* drain it before proceeding with destruction */ |
4691 | drain_workqueue(wq); | |
c8efcc25 | 4692 | |
def98c84 TH |
4693 | /* kill rescuer, if sanity checks fail, leave it w/o rescuer */ |
4694 | if (wq->rescuer) { | |
4695 | struct worker *rescuer = wq->rescuer; | |
4696 | ||
4697 | /* this prevents new queueing */ | |
a9b8a985 | 4698 | raw_spin_lock_irq(&wq_mayday_lock); |
def98c84 | 4699 | wq->rescuer = NULL; |
a9b8a985 | 4700 | raw_spin_unlock_irq(&wq_mayday_lock); |
def98c84 TH |
4701 | |
4702 | /* rescuer will empty maydays list before exiting */ | |
4703 | kthread_stop(rescuer->task); | |
8efe1223 | 4704 | kfree(rescuer); |
def98c84 TH |
4705 | } |
4706 | ||
c29eb853 TH |
4707 | /* |
4708 | * Sanity checks - grab all the locks so that we wait for all | |
4709 | * in-flight operations which may do put_pwq(). | |
4710 | */ | |
4711 | mutex_lock(&wq_pool_mutex); | |
b09f4fd3 | 4712 | mutex_lock(&wq->mutex); |
49e3cf44 | 4713 | for_each_pwq(pwq, wq) { |
a9b8a985 | 4714 | raw_spin_lock_irq(&pwq->pool->lock); |
c29eb853 | 4715 | if (WARN_ON(pwq_busy(pwq))) { |
1d9a6159 KW |
4716 | pr_warn("%s: %s has the following busy pwq\n", |
4717 | __func__, wq->name); | |
c29eb853 | 4718 | show_pwq(pwq); |
a9b8a985 | 4719 | raw_spin_unlock_irq(&pwq->pool->lock); |
b09f4fd3 | 4720 | mutex_unlock(&wq->mutex); |
c29eb853 | 4721 | mutex_unlock(&wq_pool_mutex); |
55df0933 | 4722 | show_one_workqueue(wq); |
6183c009 | 4723 | return; |
76af4d93 | 4724 | } |
a9b8a985 | 4725 | raw_spin_unlock_irq(&pwq->pool->lock); |
6183c009 | 4726 | } |
b09f4fd3 | 4727 | mutex_unlock(&wq->mutex); |
6183c009 | 4728 | |
a0a1a5fd TH |
4729 | /* |
4730 | * wq list is used to freeze wq, remove from list after | |
4731 | * flushing is complete in case freeze races us. | |
4732 | */ | |
e2dca7ad | 4733 | list_del_rcu(&wq->list); |
68e13a67 | 4734 | mutex_unlock(&wq_pool_mutex); |
3af24433 | 4735 | |
636b927e TH |
4736 | /* |
4737 | * We're the sole accessor of @wq. Directly access cpu_pwq and dfl_pwq | |
4738 | * to put the base refs. @wq will be auto-destroyed from the last | |
4739 | * pwq_put. RCU read lock prevents @wq from going away from under us. | |
4740 | */ | |
4741 | rcu_read_lock(); | |
4c16bd32 | 4742 | |
636b927e TH |
4743 | for_each_possible_cpu(cpu) { |
4744 | pwq = rcu_access_pointer(*per_cpu_ptr(wq->cpu_pwq, cpu)); | |
4745 | RCU_INIT_POINTER(*per_cpu_ptr(wq->cpu_pwq, cpu), NULL); | |
dce90d47 | 4746 | put_pwq_unlocked(pwq); |
29c91e99 | 4747 | } |
636b927e TH |
4748 | |
4749 | put_pwq_unlocked(wq->dfl_pwq); | |
4750 | wq->dfl_pwq = NULL; | |
4751 | ||
4752 | rcu_read_unlock(); | |
3af24433 ON |
4753 | } |
4754 | EXPORT_SYMBOL_GPL(destroy_workqueue); | |
4755 | ||
dcd989cb TH |
4756 | /** |
4757 | * workqueue_set_max_active - adjust max_active of a workqueue | |
4758 | * @wq: target workqueue | |
4759 | * @max_active: new max_active value. | |
4760 | * | |
4761 | * Set max_active of @wq to @max_active. | |
4762 | * | |
4763 | * CONTEXT: | |
4764 | * Don't call from IRQ context. | |
4765 | */ | |
4766 | void workqueue_set_max_active(struct workqueue_struct *wq, int max_active) | |
4767 | { | |
49e3cf44 | 4768 | struct pool_workqueue *pwq; |
dcd989cb | 4769 | |
8719dcea | 4770 | /* disallow meddling with max_active for ordered workqueues */ |
0a94efb5 | 4771 | if (WARN_ON(wq->flags & __WQ_ORDERED_EXPLICIT)) |
8719dcea TH |
4772 | return; |
4773 | ||
f3421797 | 4774 | max_active = wq_clamp_max_active(max_active, wq->flags, wq->name); |
dcd989cb | 4775 | |
a357fc03 | 4776 | mutex_lock(&wq->mutex); |
dcd989cb | 4777 | |
0a94efb5 | 4778 | wq->flags &= ~__WQ_ORDERED; |
dcd989cb TH |
4779 | wq->saved_max_active = max_active; |
4780 | ||
699ce097 TH |
4781 | for_each_pwq(pwq, wq) |
4782 | pwq_adjust_max_active(pwq); | |
93981800 | 4783 | |
a357fc03 | 4784 | mutex_unlock(&wq->mutex); |
15316ba8 | 4785 | } |
dcd989cb | 4786 | EXPORT_SYMBOL_GPL(workqueue_set_max_active); |
15316ba8 | 4787 | |
27d4ee03 LW |
4788 | /** |
4789 | * current_work - retrieve %current task's work struct | |
4790 | * | |
4791 | * Determine if %current task is a workqueue worker and what it's working on. | |
4792 | * Useful to find out the context that the %current task is running in. | |
4793 | * | |
4794 | * Return: work struct if %current task is a workqueue worker, %NULL otherwise. | |
4795 | */ | |
4796 | struct work_struct *current_work(void) | |
4797 | { | |
4798 | struct worker *worker = current_wq_worker(); | |
4799 | ||
4800 | return worker ? worker->current_work : NULL; | |
4801 | } | |
4802 | EXPORT_SYMBOL(current_work); | |
4803 | ||
e6267616 TH |
4804 | /** |
4805 | * current_is_workqueue_rescuer - is %current workqueue rescuer? | |
4806 | * | |
4807 | * Determine whether %current is a workqueue rescuer. Can be used from | |
4808 | * work functions to determine whether it's being run off the rescuer task. | |
d185af30 YB |
4809 | * |
4810 | * Return: %true if %current is a workqueue rescuer. %false otherwise. | |
e6267616 TH |
4811 | */ |
4812 | bool current_is_workqueue_rescuer(void) | |
4813 | { | |
4814 | struct worker *worker = current_wq_worker(); | |
4815 | ||
6a092dfd | 4816 | return worker && worker->rescue_wq; |
e6267616 TH |
4817 | } |
4818 | ||
eef6a7d5 | 4819 | /** |
dcd989cb TH |
4820 | * workqueue_congested - test whether a workqueue is congested |
4821 | * @cpu: CPU in question | |
4822 | * @wq: target workqueue | |
eef6a7d5 | 4823 | * |
dcd989cb TH |
4824 | * Test whether @wq's cpu workqueue for @cpu is congested. There is |
4825 | * no synchronization around this function and the test result is | |
4826 | * unreliable and only useful as advisory hints or for debugging. | |
eef6a7d5 | 4827 | * |
d3251859 | 4828 | * If @cpu is WORK_CPU_UNBOUND, the test is performed on the local CPU. |
636b927e TH |
4829 | * |
4830 | * With the exception of ordered workqueues, all workqueues have per-cpu | |
4831 | * pool_workqueues, each with its own congested state. A workqueue being | |
4832 | * congested on one CPU doesn't mean that the workqueue is contested on any | |
4833 | * other CPUs. | |
d3251859 | 4834 | * |
d185af30 | 4835 | * Return: |
dcd989cb | 4836 | * %true if congested, %false otherwise. |
eef6a7d5 | 4837 | */ |
d84ff051 | 4838 | bool workqueue_congested(int cpu, struct workqueue_struct *wq) |
1da177e4 | 4839 | { |
7fb98ea7 | 4840 | struct pool_workqueue *pwq; |
76af4d93 TH |
4841 | bool ret; |
4842 | ||
24acfb71 TG |
4843 | rcu_read_lock(); |
4844 | preempt_disable(); | |
7fb98ea7 | 4845 | |
d3251859 TH |
4846 | if (cpu == WORK_CPU_UNBOUND) |
4847 | cpu = smp_processor_id(); | |
4848 | ||
636b927e | 4849 | pwq = *per_cpu_ptr(wq->cpu_pwq, cpu); |
f97a4a1a | 4850 | ret = !list_empty(&pwq->inactive_works); |
636b927e | 4851 | |
24acfb71 TG |
4852 | preempt_enable(); |
4853 | rcu_read_unlock(); | |
76af4d93 TH |
4854 | |
4855 | return ret; | |
1da177e4 | 4856 | } |
dcd989cb | 4857 | EXPORT_SYMBOL_GPL(workqueue_congested); |
1da177e4 | 4858 | |
dcd989cb TH |
4859 | /** |
4860 | * work_busy - test whether a work is currently pending or running | |
4861 | * @work: the work to be tested | |
4862 | * | |
4863 | * Test whether @work is currently pending or running. There is no | |
4864 | * synchronization around this function and the test result is | |
4865 | * unreliable and only useful as advisory hints or for debugging. | |
dcd989cb | 4866 | * |
d185af30 | 4867 | * Return: |
dcd989cb TH |
4868 | * OR'd bitmask of WORK_BUSY_* bits. |
4869 | */ | |
4870 | unsigned int work_busy(struct work_struct *work) | |
1da177e4 | 4871 | { |
fa1b54e6 | 4872 | struct worker_pool *pool; |
dcd989cb TH |
4873 | unsigned long flags; |
4874 | unsigned int ret = 0; | |
1da177e4 | 4875 | |
dcd989cb TH |
4876 | if (work_pending(work)) |
4877 | ret |= WORK_BUSY_PENDING; | |
1da177e4 | 4878 | |
24acfb71 | 4879 | rcu_read_lock(); |
fa1b54e6 | 4880 | pool = get_work_pool(work); |
038366c5 | 4881 | if (pool) { |
a9b8a985 | 4882 | raw_spin_lock_irqsave(&pool->lock, flags); |
038366c5 LJ |
4883 | if (find_worker_executing_work(pool, work)) |
4884 | ret |= WORK_BUSY_RUNNING; | |
a9b8a985 | 4885 | raw_spin_unlock_irqrestore(&pool->lock, flags); |
038366c5 | 4886 | } |
24acfb71 | 4887 | rcu_read_unlock(); |
1da177e4 | 4888 | |
dcd989cb | 4889 | return ret; |
1da177e4 | 4890 | } |
dcd989cb | 4891 | EXPORT_SYMBOL_GPL(work_busy); |
1da177e4 | 4892 | |
3d1cb205 TH |
4893 | /** |
4894 | * set_worker_desc - set description for the current work item | |
4895 | * @fmt: printf-style format string | |
4896 | * @...: arguments for the format string | |
4897 | * | |
4898 | * This function can be called by a running work function to describe what | |
4899 | * the work item is about. If the worker task gets dumped, this | |
4900 | * information will be printed out together to help debugging. The | |
4901 | * description can be at most WORKER_DESC_LEN including the trailing '\0'. | |
4902 | */ | |
4903 | void set_worker_desc(const char *fmt, ...) | |
4904 | { | |
4905 | struct worker *worker = current_wq_worker(); | |
4906 | va_list args; | |
4907 | ||
4908 | if (worker) { | |
4909 | va_start(args, fmt); | |
4910 | vsnprintf(worker->desc, sizeof(worker->desc), fmt, args); | |
4911 | va_end(args); | |
3d1cb205 TH |
4912 | } |
4913 | } | |
5c750d58 | 4914 | EXPORT_SYMBOL_GPL(set_worker_desc); |
3d1cb205 TH |
4915 | |
4916 | /** | |
4917 | * print_worker_info - print out worker information and description | |
4918 | * @log_lvl: the log level to use when printing | |
4919 | * @task: target task | |
4920 | * | |
4921 | * If @task is a worker and currently executing a work item, print out the | |
4922 | * name of the workqueue being serviced and worker description set with | |
4923 | * set_worker_desc() by the currently executing work item. | |
4924 | * | |
4925 | * This function can be safely called on any task as long as the | |
4926 | * task_struct itself is accessible. While safe, this function isn't | |
4927 | * synchronized and may print out mixups or garbages of limited length. | |
4928 | */ | |
4929 | void print_worker_info(const char *log_lvl, struct task_struct *task) | |
4930 | { | |
4931 | work_func_t *fn = NULL; | |
4932 | char name[WQ_NAME_LEN] = { }; | |
4933 | char desc[WORKER_DESC_LEN] = { }; | |
4934 | struct pool_workqueue *pwq = NULL; | |
4935 | struct workqueue_struct *wq = NULL; | |
3d1cb205 TH |
4936 | struct worker *worker; |
4937 | ||
4938 | if (!(task->flags & PF_WQ_WORKER)) | |
4939 | return; | |
4940 | ||
4941 | /* | |
4942 | * This function is called without any synchronization and @task | |
4943 | * could be in any state. Be careful with dereferences. | |
4944 | */ | |
e700591a | 4945 | worker = kthread_probe_data(task); |
3d1cb205 TH |
4946 | |
4947 | /* | |
8bf89593 TH |
4948 | * Carefully copy the associated workqueue's workfn, name and desc. |
4949 | * Keep the original last '\0' in case the original is garbage. | |
3d1cb205 | 4950 | */ |
fe557319 CH |
4951 | copy_from_kernel_nofault(&fn, &worker->current_func, sizeof(fn)); |
4952 | copy_from_kernel_nofault(&pwq, &worker->current_pwq, sizeof(pwq)); | |
4953 | copy_from_kernel_nofault(&wq, &pwq->wq, sizeof(wq)); | |
4954 | copy_from_kernel_nofault(name, wq->name, sizeof(name) - 1); | |
4955 | copy_from_kernel_nofault(desc, worker->desc, sizeof(desc) - 1); | |
3d1cb205 TH |
4956 | |
4957 | if (fn || name[0] || desc[0]) { | |
d75f773c | 4958 | printk("%sWorkqueue: %s %ps", log_lvl, name, fn); |
8bf89593 | 4959 | if (strcmp(name, desc)) |
3d1cb205 TH |
4960 | pr_cont(" (%s)", desc); |
4961 | pr_cont("\n"); | |
4962 | } | |
4963 | } | |
4964 | ||
3494fc30 TH |
4965 | static void pr_cont_pool_info(struct worker_pool *pool) |
4966 | { | |
4967 | pr_cont(" cpus=%*pbl", nr_cpumask_bits, pool->attrs->cpumask); | |
4968 | if (pool->node != NUMA_NO_NODE) | |
4969 | pr_cont(" node=%d", pool->node); | |
4970 | pr_cont(" flags=0x%x nice=%d", pool->flags, pool->attrs->nice); | |
4971 | } | |
4972 | ||
c76feb0d PM |
4973 | struct pr_cont_work_struct { |
4974 | bool comma; | |
4975 | work_func_t func; | |
4976 | long ctr; | |
4977 | }; | |
4978 | ||
4979 | static void pr_cont_work_flush(bool comma, work_func_t func, struct pr_cont_work_struct *pcwsp) | |
4980 | { | |
4981 | if (!pcwsp->ctr) | |
4982 | goto out_record; | |
4983 | if (func == pcwsp->func) { | |
4984 | pcwsp->ctr++; | |
4985 | return; | |
4986 | } | |
4987 | if (pcwsp->ctr == 1) | |
4988 | pr_cont("%s %ps", pcwsp->comma ? "," : "", pcwsp->func); | |
4989 | else | |
4990 | pr_cont("%s %ld*%ps", pcwsp->comma ? "," : "", pcwsp->ctr, pcwsp->func); | |
4991 | pcwsp->ctr = 0; | |
4992 | out_record: | |
4993 | if ((long)func == -1L) | |
4994 | return; | |
4995 | pcwsp->comma = comma; | |
4996 | pcwsp->func = func; | |
4997 | pcwsp->ctr = 1; | |
4998 | } | |
4999 | ||
5000 | static void pr_cont_work(bool comma, struct work_struct *work, struct pr_cont_work_struct *pcwsp) | |
3494fc30 TH |
5001 | { |
5002 | if (work->func == wq_barrier_func) { | |
5003 | struct wq_barrier *barr; | |
5004 | ||
5005 | barr = container_of(work, struct wq_barrier, work); | |
5006 | ||
c76feb0d | 5007 | pr_cont_work_flush(comma, (work_func_t)-1, pcwsp); |
3494fc30 TH |
5008 | pr_cont("%s BAR(%d)", comma ? "," : "", |
5009 | task_pid_nr(barr->task)); | |
5010 | } else { | |
c76feb0d PM |
5011 | if (!comma) |
5012 | pr_cont_work_flush(comma, (work_func_t)-1, pcwsp); | |
5013 | pr_cont_work_flush(comma, work->func, pcwsp); | |
3494fc30 TH |
5014 | } |
5015 | } | |
5016 | ||
5017 | static void show_pwq(struct pool_workqueue *pwq) | |
5018 | { | |
c76feb0d | 5019 | struct pr_cont_work_struct pcws = { .ctr = 0, }; |
3494fc30 TH |
5020 | struct worker_pool *pool = pwq->pool; |
5021 | struct work_struct *work; | |
5022 | struct worker *worker; | |
5023 | bool has_in_flight = false, has_pending = false; | |
5024 | int bkt; | |
5025 | ||
5026 | pr_info(" pwq %d:", pool->id); | |
5027 | pr_cont_pool_info(pool); | |
5028 | ||
e66b39af TH |
5029 | pr_cont(" active=%d/%d refcnt=%d%s\n", |
5030 | pwq->nr_active, pwq->max_active, pwq->refcnt, | |
3494fc30 TH |
5031 | !list_empty(&pwq->mayday_node) ? " MAYDAY" : ""); |
5032 | ||
5033 | hash_for_each(pool->busy_hash, bkt, worker, hentry) { | |
5034 | if (worker->current_pwq == pwq) { | |
5035 | has_in_flight = true; | |
5036 | break; | |
5037 | } | |
5038 | } | |
5039 | if (has_in_flight) { | |
5040 | bool comma = false; | |
5041 | ||
5042 | pr_info(" in-flight:"); | |
5043 | hash_for_each(pool->busy_hash, bkt, worker, hentry) { | |
5044 | if (worker->current_pwq != pwq) | |
5045 | continue; | |
5046 | ||
d75f773c | 5047 | pr_cont("%s %d%s:%ps", comma ? "," : "", |
3494fc30 | 5048 | task_pid_nr(worker->task), |
30ae2fc0 | 5049 | worker->rescue_wq ? "(RESCUER)" : "", |
3494fc30 TH |
5050 | worker->current_func); |
5051 | list_for_each_entry(work, &worker->scheduled, entry) | |
c76feb0d PM |
5052 | pr_cont_work(false, work, &pcws); |
5053 | pr_cont_work_flush(comma, (work_func_t)-1L, &pcws); | |
3494fc30 TH |
5054 | comma = true; |
5055 | } | |
5056 | pr_cont("\n"); | |
5057 | } | |
5058 | ||
5059 | list_for_each_entry(work, &pool->worklist, entry) { | |
5060 | if (get_work_pwq(work) == pwq) { | |
5061 | has_pending = true; | |
5062 | break; | |
5063 | } | |
5064 | } | |
5065 | if (has_pending) { | |
5066 | bool comma = false; | |
5067 | ||
5068 | pr_info(" pending:"); | |
5069 | list_for_each_entry(work, &pool->worklist, entry) { | |
5070 | if (get_work_pwq(work) != pwq) | |
5071 | continue; | |
5072 | ||
c76feb0d | 5073 | pr_cont_work(comma, work, &pcws); |
3494fc30 TH |
5074 | comma = !(*work_data_bits(work) & WORK_STRUCT_LINKED); |
5075 | } | |
c76feb0d | 5076 | pr_cont_work_flush(comma, (work_func_t)-1L, &pcws); |
3494fc30 TH |
5077 | pr_cont("\n"); |
5078 | } | |
5079 | ||
f97a4a1a | 5080 | if (!list_empty(&pwq->inactive_works)) { |
3494fc30 TH |
5081 | bool comma = false; |
5082 | ||
f97a4a1a LJ |
5083 | pr_info(" inactive:"); |
5084 | list_for_each_entry(work, &pwq->inactive_works, entry) { | |
c76feb0d | 5085 | pr_cont_work(comma, work, &pcws); |
3494fc30 TH |
5086 | comma = !(*work_data_bits(work) & WORK_STRUCT_LINKED); |
5087 | } | |
c76feb0d | 5088 | pr_cont_work_flush(comma, (work_func_t)-1L, &pcws); |
3494fc30 TH |
5089 | pr_cont("\n"); |
5090 | } | |
5091 | } | |
5092 | ||
5093 | /** | |
55df0933 IK |
5094 | * show_one_workqueue - dump state of specified workqueue |
5095 | * @wq: workqueue whose state will be printed | |
3494fc30 | 5096 | */ |
55df0933 | 5097 | void show_one_workqueue(struct workqueue_struct *wq) |
3494fc30 | 5098 | { |
55df0933 IK |
5099 | struct pool_workqueue *pwq; |
5100 | bool idle = true; | |
3494fc30 | 5101 | unsigned long flags; |
3494fc30 | 5102 | |
55df0933 IK |
5103 | for_each_pwq(pwq, wq) { |
5104 | if (pwq->nr_active || !list_empty(&pwq->inactive_works)) { | |
5105 | idle = false; | |
5106 | break; | |
3494fc30 | 5107 | } |
55df0933 IK |
5108 | } |
5109 | if (idle) /* Nothing to print for idle workqueue */ | |
5110 | return; | |
3494fc30 | 5111 | |
55df0933 | 5112 | pr_info("workqueue %s: flags=0x%x\n", wq->name, wq->flags); |
3494fc30 | 5113 | |
55df0933 IK |
5114 | for_each_pwq(pwq, wq) { |
5115 | raw_spin_lock_irqsave(&pwq->pool->lock, flags); | |
5116 | if (pwq->nr_active || !list_empty(&pwq->inactive_works)) { | |
62635ea8 | 5117 | /* |
55df0933 IK |
5118 | * Defer printing to avoid deadlocks in console |
5119 | * drivers that queue work while holding locks | |
5120 | * also taken in their write paths. | |
62635ea8 | 5121 | */ |
55df0933 IK |
5122 | printk_deferred_enter(); |
5123 | show_pwq(pwq); | |
5124 | printk_deferred_exit(); | |
3494fc30 | 5125 | } |
55df0933 | 5126 | raw_spin_unlock_irqrestore(&pwq->pool->lock, flags); |
62635ea8 SS |
5127 | /* |
5128 | * We could be printing a lot from atomic context, e.g. | |
55df0933 | 5129 | * sysrq-t -> show_all_workqueues(). Avoid triggering |
62635ea8 SS |
5130 | * hard lockup. |
5131 | */ | |
5132 | touch_nmi_watchdog(); | |
3494fc30 TH |
5133 | } |
5134 | ||
55df0933 IK |
5135 | } |
5136 | ||
5137 | /** | |
5138 | * show_one_worker_pool - dump state of specified worker pool | |
5139 | * @pool: worker pool whose state will be printed | |
5140 | */ | |
5141 | static void show_one_worker_pool(struct worker_pool *pool) | |
5142 | { | |
5143 | struct worker *worker; | |
5144 | bool first = true; | |
5145 | unsigned long flags; | |
335a42eb | 5146 | unsigned long hung = 0; |
55df0933 IK |
5147 | |
5148 | raw_spin_lock_irqsave(&pool->lock, flags); | |
5149 | if (pool->nr_workers == pool->nr_idle) | |
5150 | goto next_pool; | |
335a42eb PM |
5151 | |
5152 | /* How long the first pending work is waiting for a worker. */ | |
5153 | if (!list_empty(&pool->worklist)) | |
5154 | hung = jiffies_to_msecs(jiffies - pool->watchdog_ts) / 1000; | |
5155 | ||
55df0933 IK |
5156 | /* |
5157 | * Defer printing to avoid deadlocks in console drivers that | |
5158 | * queue work while holding locks also taken in their write | |
5159 | * paths. | |
5160 | */ | |
5161 | printk_deferred_enter(); | |
5162 | pr_info("pool %d:", pool->id); | |
5163 | pr_cont_pool_info(pool); | |
335a42eb | 5164 | pr_cont(" hung=%lus workers=%d", hung, pool->nr_workers); |
55df0933 IK |
5165 | if (pool->manager) |
5166 | pr_cont(" manager: %d", | |
5167 | task_pid_nr(pool->manager->task)); | |
5168 | list_for_each_entry(worker, &pool->idle_list, entry) { | |
5169 | pr_cont(" %s%d", first ? "idle: " : "", | |
5170 | task_pid_nr(worker->task)); | |
5171 | first = false; | |
5172 | } | |
5173 | pr_cont("\n"); | |
5174 | printk_deferred_exit(); | |
5175 | next_pool: | |
5176 | raw_spin_unlock_irqrestore(&pool->lock, flags); | |
5177 | /* | |
5178 | * We could be printing a lot from atomic context, e.g. | |
5179 | * sysrq-t -> show_all_workqueues(). Avoid triggering | |
5180 | * hard lockup. | |
5181 | */ | |
5182 | touch_nmi_watchdog(); | |
5183 | ||
5184 | } | |
5185 | ||
5186 | /** | |
5187 | * show_all_workqueues - dump workqueue state | |
5188 | * | |
704bc669 | 5189 | * Called from a sysrq handler and prints out all busy workqueues and pools. |
55df0933 IK |
5190 | */ |
5191 | void show_all_workqueues(void) | |
5192 | { | |
5193 | struct workqueue_struct *wq; | |
5194 | struct worker_pool *pool; | |
5195 | int pi; | |
5196 | ||
5197 | rcu_read_lock(); | |
5198 | ||
5199 | pr_info("Showing busy workqueues and worker pools:\n"); | |
5200 | ||
5201 | list_for_each_entry_rcu(wq, &workqueues, list) | |
5202 | show_one_workqueue(wq); | |
5203 | ||
5204 | for_each_pool(pool, pi) | |
5205 | show_one_worker_pool(pool); | |
5206 | ||
24acfb71 | 5207 | rcu_read_unlock(); |
3494fc30 TH |
5208 | } |
5209 | ||
704bc669 JL |
5210 | /** |
5211 | * show_freezable_workqueues - dump freezable workqueue state | |
5212 | * | |
5213 | * Called from try_to_freeze_tasks() and prints out all freezable workqueues | |
5214 | * still busy. | |
5215 | */ | |
5216 | void show_freezable_workqueues(void) | |
5217 | { | |
5218 | struct workqueue_struct *wq; | |
5219 | ||
5220 | rcu_read_lock(); | |
5221 | ||
5222 | pr_info("Showing freezable workqueues that are still busy:\n"); | |
5223 | ||
5224 | list_for_each_entry_rcu(wq, &workqueues, list) { | |
5225 | if (!(wq->flags & WQ_FREEZABLE)) | |
5226 | continue; | |
5227 | show_one_workqueue(wq); | |
5228 | } | |
5229 | ||
5230 | rcu_read_unlock(); | |
5231 | } | |
5232 | ||
6b59808b TH |
5233 | /* used to show worker information through /proc/PID/{comm,stat,status} */ |
5234 | void wq_worker_comm(char *buf, size_t size, struct task_struct *task) | |
5235 | { | |
6b59808b TH |
5236 | int off; |
5237 | ||
5238 | /* always show the actual comm */ | |
5239 | off = strscpy(buf, task->comm, size); | |
5240 | if (off < 0) | |
5241 | return; | |
5242 | ||
197f6acc | 5243 | /* stabilize PF_WQ_WORKER and worker pool association */ |
6b59808b TH |
5244 | mutex_lock(&wq_pool_attach_mutex); |
5245 | ||
197f6acc TH |
5246 | if (task->flags & PF_WQ_WORKER) { |
5247 | struct worker *worker = kthread_data(task); | |
5248 | struct worker_pool *pool = worker->pool; | |
6b59808b | 5249 | |
197f6acc | 5250 | if (pool) { |
a9b8a985 | 5251 | raw_spin_lock_irq(&pool->lock); |
197f6acc TH |
5252 | /* |
5253 | * ->desc tracks information (wq name or | |
5254 | * set_worker_desc()) for the latest execution. If | |
5255 | * current, prepend '+', otherwise '-'. | |
5256 | */ | |
5257 | if (worker->desc[0] != '\0') { | |
5258 | if (worker->current_work) | |
5259 | scnprintf(buf + off, size - off, "+%s", | |
5260 | worker->desc); | |
5261 | else | |
5262 | scnprintf(buf + off, size - off, "-%s", | |
5263 | worker->desc); | |
5264 | } | |
a9b8a985 | 5265 | raw_spin_unlock_irq(&pool->lock); |
6b59808b | 5266 | } |
6b59808b TH |
5267 | } |
5268 | ||
5269 | mutex_unlock(&wq_pool_attach_mutex); | |
5270 | } | |
5271 | ||
66448bc2 MM |
5272 | #ifdef CONFIG_SMP |
5273 | ||
db7bccf4 TH |
5274 | /* |
5275 | * CPU hotplug. | |
5276 | * | |
e22bee78 | 5277 | * There are two challenges in supporting CPU hotplug. Firstly, there |
112202d9 | 5278 | * are a lot of assumptions on strong associations among work, pwq and |
706026c2 | 5279 | * pool which make migrating pending and scheduled works very |
e22bee78 | 5280 | * difficult to implement without impacting hot paths. Secondly, |
94cf58bb | 5281 | * worker pools serve mix of short, long and very long running works making |
e22bee78 TH |
5282 | * blocked draining impractical. |
5283 | * | |
24647570 | 5284 | * This is solved by allowing the pools to be disassociated from the CPU |
628c78e7 TH |
5285 | * running as an unbound one and allowing it to be reattached later if the |
5286 | * cpu comes back online. | |
db7bccf4 | 5287 | */ |
1da177e4 | 5288 | |
e8b3f8db | 5289 | static void unbind_workers(int cpu) |
3af24433 | 5290 | { |
4ce62e9e | 5291 | struct worker_pool *pool; |
db7bccf4 | 5292 | struct worker *worker; |
3af24433 | 5293 | |
f02ae73a | 5294 | for_each_cpu_worker_pool(pool, cpu) { |
1258fae7 | 5295 | mutex_lock(&wq_pool_attach_mutex); |
a9b8a985 | 5296 | raw_spin_lock_irq(&pool->lock); |
3af24433 | 5297 | |
94cf58bb | 5298 | /* |
92f9c5c4 | 5299 | * We've blocked all attach/detach operations. Make all workers |
94cf58bb | 5300 | * unbound and set DISASSOCIATED. Before this, all workers |
11b45b0b | 5301 | * must be on the cpu. After this, they may become diasporas. |
b4ac9384 LJ |
5302 | * And the preemption disabled section in their sched callbacks |
5303 | * are guaranteed to see WORKER_UNBOUND since the code here | |
5304 | * is on the same cpu. | |
94cf58bb | 5305 | */ |
da028469 | 5306 | for_each_pool_worker(worker, pool) |
c9e7cf27 | 5307 | worker->flags |= WORKER_UNBOUND; |
06ba38a9 | 5308 | |
24647570 | 5309 | pool->flags |= POOL_DISASSOCIATED; |
f2d5a0ee | 5310 | |
eb283428 | 5311 | /* |
989442d7 LJ |
5312 | * The handling of nr_running in sched callbacks are disabled |
5313 | * now. Zap nr_running. After this, nr_running stays zero and | |
5314 | * need_more_worker() and keep_working() are always true as | |
5315 | * long as the worklist is not empty. This pool now behaves as | |
5316 | * an unbound (in terms of concurrency management) pool which | |
eb283428 LJ |
5317 | * are served by workers tied to the pool. |
5318 | */ | |
bc35f7ef | 5319 | pool->nr_running = 0; |
eb283428 LJ |
5320 | |
5321 | /* | |
5322 | * With concurrency management just turned off, a busy | |
5323 | * worker blocking could lead to lengthy stalls. Kick off | |
5324 | * unbound chain execution of currently pending work items. | |
5325 | */ | |
eb283428 | 5326 | wake_up_worker(pool); |
989442d7 | 5327 | |
a9b8a985 | 5328 | raw_spin_unlock_irq(&pool->lock); |
989442d7 | 5329 | |
793777bc VS |
5330 | for_each_pool_worker(worker, pool) |
5331 | unbind_worker(worker); | |
989442d7 LJ |
5332 | |
5333 | mutex_unlock(&wq_pool_attach_mutex); | |
eb283428 | 5334 | } |
3af24433 | 5335 | } |
3af24433 | 5336 | |
bd7c089e TH |
5337 | /** |
5338 | * rebind_workers - rebind all workers of a pool to the associated CPU | |
5339 | * @pool: pool of interest | |
5340 | * | |
a9ab775b | 5341 | * @pool->cpu is coming online. Rebind all workers to the CPU. |
bd7c089e TH |
5342 | */ |
5343 | static void rebind_workers(struct worker_pool *pool) | |
5344 | { | |
a9ab775b | 5345 | struct worker *worker; |
bd7c089e | 5346 | |
1258fae7 | 5347 | lockdep_assert_held(&wq_pool_attach_mutex); |
bd7c089e | 5348 | |
a9ab775b TH |
5349 | /* |
5350 | * Restore CPU affinity of all workers. As all idle workers should | |
5351 | * be on the run-queue of the associated CPU before any local | |
402dd89d | 5352 | * wake-ups for concurrency management happen, restore CPU affinity |
a9ab775b TH |
5353 | * of all workers first and then clear UNBOUND. As we're called |
5354 | * from CPU_ONLINE, the following shouldn't fail. | |
5355 | */ | |
c63a2e52 VS |
5356 | for_each_pool_worker(worker, pool) { |
5357 | kthread_set_per_cpu(worker->task, pool->cpu); | |
5358 | WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task, | |
5359 | pool->attrs->cpumask) < 0); | |
5360 | } | |
bd7c089e | 5361 | |
a9b8a985 | 5362 | raw_spin_lock_irq(&pool->lock); |
f7c17d26 | 5363 | |
3de5e884 | 5364 | pool->flags &= ~POOL_DISASSOCIATED; |
bd7c089e | 5365 | |
da028469 | 5366 | for_each_pool_worker(worker, pool) { |
a9ab775b | 5367 | unsigned int worker_flags = worker->flags; |
bd7c089e | 5368 | |
a9ab775b TH |
5369 | /* |
5370 | * We want to clear UNBOUND but can't directly call | |
5371 | * worker_clr_flags() or adjust nr_running. Atomically | |
5372 | * replace UNBOUND with another NOT_RUNNING flag REBOUND. | |
5373 | * @worker will clear REBOUND using worker_clr_flags() when | |
5374 | * it initiates the next execution cycle thus restoring | |
5375 | * concurrency management. Note that when or whether | |
5376 | * @worker clears REBOUND doesn't affect correctness. | |
5377 | * | |
c95491ed | 5378 | * WRITE_ONCE() is necessary because @worker->flags may be |
a9ab775b | 5379 | * tested without holding any lock in |
6d25be57 | 5380 | * wq_worker_running(). Without it, NOT_RUNNING test may |
a9ab775b TH |
5381 | * fail incorrectly leading to premature concurrency |
5382 | * management operations. | |
5383 | */ | |
5384 | WARN_ON_ONCE(!(worker_flags & WORKER_UNBOUND)); | |
5385 | worker_flags |= WORKER_REBOUND; | |
5386 | worker_flags &= ~WORKER_UNBOUND; | |
c95491ed | 5387 | WRITE_ONCE(worker->flags, worker_flags); |
bd7c089e | 5388 | } |
a9ab775b | 5389 | |
a9b8a985 | 5390 | raw_spin_unlock_irq(&pool->lock); |
bd7c089e TH |
5391 | } |
5392 | ||
7dbc725e TH |
5393 | /** |
5394 | * restore_unbound_workers_cpumask - restore cpumask of unbound workers | |
5395 | * @pool: unbound pool of interest | |
5396 | * @cpu: the CPU which is coming up | |
5397 | * | |
5398 | * An unbound pool may end up with a cpumask which doesn't have any online | |
5399 | * CPUs. When a worker of such pool get scheduled, the scheduler resets | |
5400 | * its cpus_allowed. If @cpu is in @pool's cpumask which didn't have any | |
5401 | * online CPU before, cpus_allowed of all its workers should be restored. | |
5402 | */ | |
5403 | static void restore_unbound_workers_cpumask(struct worker_pool *pool, int cpu) | |
5404 | { | |
5405 | static cpumask_t cpumask; | |
5406 | struct worker *worker; | |
7dbc725e | 5407 | |
1258fae7 | 5408 | lockdep_assert_held(&wq_pool_attach_mutex); |
7dbc725e TH |
5409 | |
5410 | /* is @cpu allowed for @pool? */ | |
5411 | if (!cpumask_test_cpu(cpu, pool->attrs->cpumask)) | |
5412 | return; | |
5413 | ||
7dbc725e | 5414 | cpumask_and(&cpumask, pool->attrs->cpumask, cpu_online_mask); |
7dbc725e TH |
5415 | |
5416 | /* as we're called from CPU_ONLINE, the following shouldn't fail */ | |
da028469 | 5417 | for_each_pool_worker(worker, pool) |
d945b5e9 | 5418 | WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task, &cpumask) < 0); |
7dbc725e TH |
5419 | } |
5420 | ||
7ee681b2 TG |
5421 | int workqueue_prepare_cpu(unsigned int cpu) |
5422 | { | |
5423 | struct worker_pool *pool; | |
5424 | ||
5425 | for_each_cpu_worker_pool(pool, cpu) { | |
5426 | if (pool->nr_workers) | |
5427 | continue; | |
5428 | if (!create_worker(pool)) | |
5429 | return -ENOMEM; | |
5430 | } | |
5431 | return 0; | |
5432 | } | |
5433 | ||
5434 | int workqueue_online_cpu(unsigned int cpu) | |
3af24433 | 5435 | { |
4ce62e9e | 5436 | struct worker_pool *pool; |
4c16bd32 | 5437 | struct workqueue_struct *wq; |
7dbc725e | 5438 | int pi; |
3ce63377 | 5439 | |
7ee681b2 | 5440 | mutex_lock(&wq_pool_mutex); |
7dbc725e | 5441 | |
7ee681b2 | 5442 | for_each_pool(pool, pi) { |
1258fae7 | 5443 | mutex_lock(&wq_pool_attach_mutex); |
94cf58bb | 5444 | |
7ee681b2 TG |
5445 | if (pool->cpu == cpu) |
5446 | rebind_workers(pool); | |
5447 | else if (pool->cpu < 0) | |
5448 | restore_unbound_workers_cpumask(pool, cpu); | |
94cf58bb | 5449 | |
1258fae7 | 5450 | mutex_unlock(&wq_pool_attach_mutex); |
7ee681b2 | 5451 | } |
6ba94429 | 5452 | |
fef59c9c | 5453 | /* update pod affinity of unbound workqueues */ |
4cbfd3de TH |
5454 | list_for_each_entry(wq, &workqueues, list) { |
5455 | int tcpu; | |
5456 | ||
5457 | for_each_possible_cpu(tcpu) { | |
5458 | if (cpu_to_node(tcpu) == cpu_to_node(cpu)) { | |
fef59c9c | 5459 | wq_update_pod(wq, tcpu, cpu, true); |
4cbfd3de TH |
5460 | } |
5461 | } | |
5462 | } | |
6ba94429 | 5463 | |
7ee681b2 TG |
5464 | mutex_unlock(&wq_pool_mutex); |
5465 | return 0; | |
6ba94429 FW |
5466 | } |
5467 | ||
7ee681b2 | 5468 | int workqueue_offline_cpu(unsigned int cpu) |
6ba94429 | 5469 | { |
6ba94429 FW |
5470 | struct workqueue_struct *wq; |
5471 | ||
7ee681b2 | 5472 | /* unbinding per-cpu workers should happen on the local CPU */ |
e8b3f8db LJ |
5473 | if (WARN_ON(cpu != smp_processor_id())) |
5474 | return -1; | |
5475 | ||
5476 | unbind_workers(cpu); | |
7ee681b2 | 5477 | |
fef59c9c | 5478 | /* update pod affinity of unbound workqueues */ |
7ee681b2 | 5479 | mutex_lock(&wq_pool_mutex); |
4cbfd3de TH |
5480 | list_for_each_entry(wq, &workqueues, list) { |
5481 | int tcpu; | |
5482 | ||
5483 | for_each_possible_cpu(tcpu) { | |
5484 | if (cpu_to_node(tcpu) == cpu_to_node(cpu)) { | |
fef59c9c | 5485 | wq_update_pod(wq, tcpu, cpu, false); |
4cbfd3de TH |
5486 | } |
5487 | } | |
5488 | } | |
7ee681b2 TG |
5489 | mutex_unlock(&wq_pool_mutex); |
5490 | ||
7ee681b2 | 5491 | return 0; |
6ba94429 FW |
5492 | } |
5493 | ||
6ba94429 FW |
5494 | struct work_for_cpu { |
5495 | struct work_struct work; | |
5496 | long (*fn)(void *); | |
5497 | void *arg; | |
5498 | long ret; | |
5499 | }; | |
5500 | ||
5501 | static void work_for_cpu_fn(struct work_struct *work) | |
5502 | { | |
5503 | struct work_for_cpu *wfc = container_of(work, struct work_for_cpu, work); | |
5504 | ||
5505 | wfc->ret = wfc->fn(wfc->arg); | |
5506 | } | |
5507 | ||
5508 | /** | |
22aceb31 | 5509 | * work_on_cpu - run a function in thread context on a particular cpu |
6ba94429 FW |
5510 | * @cpu: the cpu to run on |
5511 | * @fn: the function to run | |
5512 | * @arg: the function arg | |
5513 | * | |
5514 | * It is up to the caller to ensure that the cpu doesn't go offline. | |
5515 | * The caller must not hold any locks which would prevent @fn from completing. | |
5516 | * | |
5517 | * Return: The value @fn returns. | |
5518 | */ | |
5519 | long work_on_cpu(int cpu, long (*fn)(void *), void *arg) | |
5520 | { | |
5521 | struct work_for_cpu wfc = { .fn = fn, .arg = arg }; | |
5522 | ||
5523 | INIT_WORK_ONSTACK(&wfc.work, work_for_cpu_fn); | |
5524 | schedule_work_on(cpu, &wfc.work); | |
5525 | flush_work(&wfc.work); | |
5526 | destroy_work_on_stack(&wfc.work); | |
5527 | return wfc.ret; | |
5528 | } | |
5529 | EXPORT_SYMBOL_GPL(work_on_cpu); | |
0e8d6a93 TG |
5530 | |
5531 | /** | |
5532 | * work_on_cpu_safe - run a function in thread context on a particular cpu | |
5533 | * @cpu: the cpu to run on | |
5534 | * @fn: the function to run | |
5535 | * @arg: the function argument | |
5536 | * | |
5537 | * Disables CPU hotplug and calls work_on_cpu(). The caller must not hold | |
5538 | * any locks which would prevent @fn from completing. | |
5539 | * | |
5540 | * Return: The value @fn returns. | |
5541 | */ | |
5542 | long work_on_cpu_safe(int cpu, long (*fn)(void *), void *arg) | |
5543 | { | |
5544 | long ret = -ENODEV; | |
5545 | ||
ffd8bea8 | 5546 | cpus_read_lock(); |
0e8d6a93 TG |
5547 | if (cpu_online(cpu)) |
5548 | ret = work_on_cpu(cpu, fn, arg); | |
ffd8bea8 | 5549 | cpus_read_unlock(); |
0e8d6a93 TG |
5550 | return ret; |
5551 | } | |
5552 | EXPORT_SYMBOL_GPL(work_on_cpu_safe); | |
6ba94429 FW |
5553 | #endif /* CONFIG_SMP */ |
5554 | ||
5555 | #ifdef CONFIG_FREEZER | |
5556 | ||
5557 | /** | |
5558 | * freeze_workqueues_begin - begin freezing workqueues | |
5559 | * | |
5560 | * Start freezing workqueues. After this function returns, all freezable | |
f97a4a1a | 5561 | * workqueues will queue new works to their inactive_works list instead of |
6ba94429 FW |
5562 | * pool->worklist. |
5563 | * | |
5564 | * CONTEXT: | |
5565 | * Grabs and releases wq_pool_mutex, wq->mutex and pool->lock's. | |
5566 | */ | |
5567 | void freeze_workqueues_begin(void) | |
5568 | { | |
5569 | struct workqueue_struct *wq; | |
5570 | struct pool_workqueue *pwq; | |
5571 | ||
5572 | mutex_lock(&wq_pool_mutex); | |
5573 | ||
5574 | WARN_ON_ONCE(workqueue_freezing); | |
5575 | workqueue_freezing = true; | |
5576 | ||
5577 | list_for_each_entry(wq, &workqueues, list) { | |
5578 | mutex_lock(&wq->mutex); | |
5579 | for_each_pwq(pwq, wq) | |
5580 | pwq_adjust_max_active(pwq); | |
5581 | mutex_unlock(&wq->mutex); | |
5582 | } | |
5583 | ||
5584 | mutex_unlock(&wq_pool_mutex); | |
5585 | } | |
5586 | ||
5587 | /** | |
5588 | * freeze_workqueues_busy - are freezable workqueues still busy? | |
5589 | * | |
5590 | * Check whether freezing is complete. This function must be called | |
5591 | * between freeze_workqueues_begin() and thaw_workqueues(). | |
5592 | * | |
5593 | * CONTEXT: | |
5594 | * Grabs and releases wq_pool_mutex. | |
5595 | * | |
5596 | * Return: | |
5597 | * %true if some freezable workqueues are still busy. %false if freezing | |
5598 | * is complete. | |
5599 | */ | |
5600 | bool freeze_workqueues_busy(void) | |
5601 | { | |
5602 | bool busy = false; | |
5603 | struct workqueue_struct *wq; | |
5604 | struct pool_workqueue *pwq; | |
5605 | ||
5606 | mutex_lock(&wq_pool_mutex); | |
5607 | ||
5608 | WARN_ON_ONCE(!workqueue_freezing); | |
5609 | ||
5610 | list_for_each_entry(wq, &workqueues, list) { | |
5611 | if (!(wq->flags & WQ_FREEZABLE)) | |
5612 | continue; | |
5613 | /* | |
5614 | * nr_active is monotonically decreasing. It's safe | |
5615 | * to peek without lock. | |
5616 | */ | |
24acfb71 | 5617 | rcu_read_lock(); |
6ba94429 FW |
5618 | for_each_pwq(pwq, wq) { |
5619 | WARN_ON_ONCE(pwq->nr_active < 0); | |
5620 | if (pwq->nr_active) { | |
5621 | busy = true; | |
24acfb71 | 5622 | rcu_read_unlock(); |
6ba94429 FW |
5623 | goto out_unlock; |
5624 | } | |
5625 | } | |
24acfb71 | 5626 | rcu_read_unlock(); |
6ba94429 FW |
5627 | } |
5628 | out_unlock: | |
5629 | mutex_unlock(&wq_pool_mutex); | |
5630 | return busy; | |
5631 | } | |
5632 | ||
5633 | /** | |
5634 | * thaw_workqueues - thaw workqueues | |
5635 | * | |
5636 | * Thaw workqueues. Normal queueing is restored and all collected | |
5637 | * frozen works are transferred to their respective pool worklists. | |
5638 | * | |
5639 | * CONTEXT: | |
5640 | * Grabs and releases wq_pool_mutex, wq->mutex and pool->lock's. | |
5641 | */ | |
5642 | void thaw_workqueues(void) | |
5643 | { | |
5644 | struct workqueue_struct *wq; | |
5645 | struct pool_workqueue *pwq; | |
5646 | ||
5647 | mutex_lock(&wq_pool_mutex); | |
5648 | ||
5649 | if (!workqueue_freezing) | |
5650 | goto out_unlock; | |
5651 | ||
5652 | workqueue_freezing = false; | |
5653 | ||
5654 | /* restore max_active and repopulate worklist */ | |
5655 | list_for_each_entry(wq, &workqueues, list) { | |
5656 | mutex_lock(&wq->mutex); | |
5657 | for_each_pwq(pwq, wq) | |
5658 | pwq_adjust_max_active(pwq); | |
5659 | mutex_unlock(&wq->mutex); | |
5660 | } | |
5661 | ||
5662 | out_unlock: | |
5663 | mutex_unlock(&wq_pool_mutex); | |
5664 | } | |
5665 | #endif /* CONFIG_FREEZER */ | |
5666 | ||
99c621ef | 5667 | static int workqueue_apply_unbound_cpumask(const cpumask_var_t unbound_cpumask) |
042f7df1 LJ |
5668 | { |
5669 | LIST_HEAD(ctxs); | |
5670 | int ret = 0; | |
5671 | struct workqueue_struct *wq; | |
5672 | struct apply_wqattrs_ctx *ctx, *n; | |
5673 | ||
5674 | lockdep_assert_held(&wq_pool_mutex); | |
5675 | ||
5676 | list_for_each_entry(wq, &workqueues, list) { | |
5677 | if (!(wq->flags & WQ_UNBOUND)) | |
5678 | continue; | |
5679 | /* creating multiple pwqs breaks ordering guarantee */ | |
5680 | if (wq->flags & __WQ_ORDERED) | |
5681 | continue; | |
5682 | ||
99c621ef | 5683 | ctx = apply_wqattrs_prepare(wq, wq->unbound_attrs, unbound_cpumask); |
042f7df1 LJ |
5684 | if (!ctx) { |
5685 | ret = -ENOMEM; | |
5686 | break; | |
5687 | } | |
5688 | ||
5689 | list_add_tail(&ctx->list, &ctxs); | |
5690 | } | |
5691 | ||
5692 | list_for_each_entry_safe(ctx, n, &ctxs, list) { | |
5693 | if (!ret) | |
5694 | apply_wqattrs_commit(ctx); | |
5695 | apply_wqattrs_cleanup(ctx); | |
5696 | } | |
5697 | ||
99c621ef LJ |
5698 | if (!ret) { |
5699 | mutex_lock(&wq_pool_attach_mutex); | |
5700 | cpumask_copy(wq_unbound_cpumask, unbound_cpumask); | |
5701 | mutex_unlock(&wq_pool_attach_mutex); | |
5702 | } | |
042f7df1 LJ |
5703 | return ret; |
5704 | } | |
5705 | ||
5706 | /** | |
5707 | * workqueue_set_unbound_cpumask - Set the low-level unbound cpumask | |
5708 | * @cpumask: the cpumask to set | |
5709 | * | |
5710 | * The low-level workqueues cpumask is a global cpumask that limits | |
5711 | * the affinity of all unbound workqueues. This function check the @cpumask | |
5712 | * and apply it to all unbound workqueues and updates all pwqs of them. | |
5713 | * | |
67dc8325 | 5714 | * Return: 0 - Success |
042f7df1 LJ |
5715 | * -EINVAL - Invalid @cpumask |
5716 | * -ENOMEM - Failed to allocate memory for attrs or pwqs. | |
5717 | */ | |
5718 | int workqueue_set_unbound_cpumask(cpumask_var_t cpumask) | |
5719 | { | |
5720 | int ret = -EINVAL; | |
042f7df1 | 5721 | |
c98a9805 TS |
5722 | /* |
5723 | * Not excluding isolated cpus on purpose. | |
5724 | * If the user wishes to include them, we allow that. | |
5725 | */ | |
042f7df1 LJ |
5726 | cpumask_and(cpumask, cpumask, cpu_possible_mask); |
5727 | if (!cpumask_empty(cpumask)) { | |
a0111cf6 | 5728 | apply_wqattrs_lock(); |
d25302e4 MD |
5729 | if (cpumask_equal(cpumask, wq_unbound_cpumask)) { |
5730 | ret = 0; | |
5731 | goto out_unlock; | |
5732 | } | |
5733 | ||
99c621ef | 5734 | ret = workqueue_apply_unbound_cpumask(cpumask); |
042f7df1 | 5735 | |
d25302e4 | 5736 | out_unlock: |
a0111cf6 | 5737 | apply_wqattrs_unlock(); |
042f7df1 | 5738 | } |
042f7df1 | 5739 | |
042f7df1 LJ |
5740 | return ret; |
5741 | } | |
5742 | ||
6ba94429 FW |
5743 | #ifdef CONFIG_SYSFS |
5744 | /* | |
5745 | * Workqueues with WQ_SYSFS flag set is visible to userland via | |
5746 | * /sys/bus/workqueue/devices/WQ_NAME. All visible workqueues have the | |
5747 | * following attributes. | |
5748 | * | |
5749 | * per_cpu RO bool : whether the workqueue is per-cpu or unbound | |
5750 | * max_active RW int : maximum number of in-flight work items | |
5751 | * | |
5752 | * Unbound workqueues have the following extra attributes. | |
5753 | * | |
6ba94429 FW |
5754 | * nice RW int : nice value of the workers |
5755 | * cpumask RW mask : bitmask of allowed CPUs for the workers | |
5756 | */ | |
5757 | struct wq_device { | |
5758 | struct workqueue_struct *wq; | |
5759 | struct device dev; | |
5760 | }; | |
5761 | ||
5762 | static struct workqueue_struct *dev_to_wq(struct device *dev) | |
5763 | { | |
5764 | struct wq_device *wq_dev = container_of(dev, struct wq_device, dev); | |
5765 | ||
5766 | return wq_dev->wq; | |
5767 | } | |
5768 | ||
5769 | static ssize_t per_cpu_show(struct device *dev, struct device_attribute *attr, | |
5770 | char *buf) | |
5771 | { | |
5772 | struct workqueue_struct *wq = dev_to_wq(dev); | |
5773 | ||
5774 | return scnprintf(buf, PAGE_SIZE, "%d\n", (bool)!(wq->flags & WQ_UNBOUND)); | |
5775 | } | |
5776 | static DEVICE_ATTR_RO(per_cpu); | |
5777 | ||
5778 | static ssize_t max_active_show(struct device *dev, | |
5779 | struct device_attribute *attr, char *buf) | |
5780 | { | |
5781 | struct workqueue_struct *wq = dev_to_wq(dev); | |
5782 | ||
5783 | return scnprintf(buf, PAGE_SIZE, "%d\n", wq->saved_max_active); | |
5784 | } | |
5785 | ||
5786 | static ssize_t max_active_store(struct device *dev, | |
5787 | struct device_attribute *attr, const char *buf, | |
5788 | size_t count) | |
5789 | { | |
5790 | struct workqueue_struct *wq = dev_to_wq(dev); | |
5791 | int val; | |
5792 | ||
5793 | if (sscanf(buf, "%d", &val) != 1 || val <= 0) | |
5794 | return -EINVAL; | |
5795 | ||
5796 | workqueue_set_max_active(wq, val); | |
5797 | return count; | |
5798 | } | |
5799 | static DEVICE_ATTR_RW(max_active); | |
5800 | ||
5801 | static struct attribute *wq_sysfs_attrs[] = { | |
5802 | &dev_attr_per_cpu.attr, | |
5803 | &dev_attr_max_active.attr, | |
5804 | NULL, | |
5805 | }; | |
5806 | ATTRIBUTE_GROUPS(wq_sysfs); | |
5807 | ||
6ba94429 FW |
5808 | static ssize_t wq_nice_show(struct device *dev, struct device_attribute *attr, |
5809 | char *buf) | |
5810 | { | |
5811 | struct workqueue_struct *wq = dev_to_wq(dev); | |
5812 | int written; | |
5813 | ||
5814 | mutex_lock(&wq->mutex); | |
5815 | written = scnprintf(buf, PAGE_SIZE, "%d\n", wq->unbound_attrs->nice); | |
5816 | mutex_unlock(&wq->mutex); | |
5817 | ||
5818 | return written; | |
5819 | } | |
5820 | ||
5821 | /* prepare workqueue_attrs for sysfs store operations */ | |
5822 | static struct workqueue_attrs *wq_sysfs_prep_attrs(struct workqueue_struct *wq) | |
5823 | { | |
5824 | struct workqueue_attrs *attrs; | |
5825 | ||
899a94fe LJ |
5826 | lockdep_assert_held(&wq_pool_mutex); |
5827 | ||
be69d00d | 5828 | attrs = alloc_workqueue_attrs(); |
6ba94429 FW |
5829 | if (!attrs) |
5830 | return NULL; | |
5831 | ||
6ba94429 | 5832 | copy_workqueue_attrs(attrs, wq->unbound_attrs); |
6ba94429 FW |
5833 | return attrs; |
5834 | } | |
5835 | ||
5836 | static ssize_t wq_nice_store(struct device *dev, struct device_attribute *attr, | |
5837 | const char *buf, size_t count) | |
5838 | { | |
5839 | struct workqueue_struct *wq = dev_to_wq(dev); | |
5840 | struct workqueue_attrs *attrs; | |
d4d3e257 LJ |
5841 | int ret = -ENOMEM; |
5842 | ||
5843 | apply_wqattrs_lock(); | |
6ba94429 FW |
5844 | |
5845 | attrs = wq_sysfs_prep_attrs(wq); | |
5846 | if (!attrs) | |
d4d3e257 | 5847 | goto out_unlock; |
6ba94429 FW |
5848 | |
5849 | if (sscanf(buf, "%d", &attrs->nice) == 1 && | |
5850 | attrs->nice >= MIN_NICE && attrs->nice <= MAX_NICE) | |
d4d3e257 | 5851 | ret = apply_workqueue_attrs_locked(wq, attrs); |
6ba94429 FW |
5852 | else |
5853 | ret = -EINVAL; | |
5854 | ||
d4d3e257 LJ |
5855 | out_unlock: |
5856 | apply_wqattrs_unlock(); | |
6ba94429 FW |
5857 | free_workqueue_attrs(attrs); |
5858 | return ret ?: count; | |
5859 | } | |
5860 | ||
5861 | static ssize_t wq_cpumask_show(struct device *dev, | |
5862 | struct device_attribute *attr, char *buf) | |
5863 | { | |
5864 | struct workqueue_struct *wq = dev_to_wq(dev); | |
5865 | int written; | |
5866 | ||
5867 | mutex_lock(&wq->mutex); | |
5868 | written = scnprintf(buf, PAGE_SIZE, "%*pb\n", | |
5869 | cpumask_pr_args(wq->unbound_attrs->cpumask)); | |
5870 | mutex_unlock(&wq->mutex); | |
5871 | return written; | |
5872 | } | |
5873 | ||
5874 | static ssize_t wq_cpumask_store(struct device *dev, | |
5875 | struct device_attribute *attr, | |
5876 | const char *buf, size_t count) | |
5877 | { | |
5878 | struct workqueue_struct *wq = dev_to_wq(dev); | |
5879 | struct workqueue_attrs *attrs; | |
d4d3e257 LJ |
5880 | int ret = -ENOMEM; |
5881 | ||
5882 | apply_wqattrs_lock(); | |
6ba94429 FW |
5883 | |
5884 | attrs = wq_sysfs_prep_attrs(wq); | |
5885 | if (!attrs) | |
d4d3e257 | 5886 | goto out_unlock; |
6ba94429 FW |
5887 | |
5888 | ret = cpumask_parse(buf, attrs->cpumask); | |
5889 | if (!ret) | |
d4d3e257 | 5890 | ret = apply_workqueue_attrs_locked(wq, attrs); |
6ba94429 | 5891 | |
d4d3e257 LJ |
5892 | out_unlock: |
5893 | apply_wqattrs_unlock(); | |
6ba94429 FW |
5894 | free_workqueue_attrs(attrs); |
5895 | return ret ?: count; | |
5896 | } | |
5897 | ||
6ba94429 | 5898 | static struct device_attribute wq_sysfs_unbound_attrs[] = { |
6ba94429 FW |
5899 | __ATTR(nice, 0644, wq_nice_show, wq_nice_store), |
5900 | __ATTR(cpumask, 0644, wq_cpumask_show, wq_cpumask_store), | |
6ba94429 FW |
5901 | __ATTR_NULL, |
5902 | }; | |
8ccad40d | 5903 | |
6ba94429 FW |
5904 | static struct bus_type wq_subsys = { |
5905 | .name = "workqueue", | |
5906 | .dev_groups = wq_sysfs_groups, | |
2d3854a3 RR |
5907 | }; |
5908 | ||
b05a7928 FW |
5909 | static ssize_t wq_unbound_cpumask_show(struct device *dev, |
5910 | struct device_attribute *attr, char *buf) | |
5911 | { | |
5912 | int written; | |
5913 | ||
042f7df1 | 5914 | mutex_lock(&wq_pool_mutex); |
b05a7928 FW |
5915 | written = scnprintf(buf, PAGE_SIZE, "%*pb\n", |
5916 | cpumask_pr_args(wq_unbound_cpumask)); | |
042f7df1 | 5917 | mutex_unlock(&wq_pool_mutex); |
b05a7928 FW |
5918 | |
5919 | return written; | |
5920 | } | |
5921 | ||
042f7df1 LJ |
5922 | static ssize_t wq_unbound_cpumask_store(struct device *dev, |
5923 | struct device_attribute *attr, const char *buf, size_t count) | |
5924 | { | |
5925 | cpumask_var_t cpumask; | |
5926 | int ret; | |
5927 | ||
5928 | if (!zalloc_cpumask_var(&cpumask, GFP_KERNEL)) | |
5929 | return -ENOMEM; | |
5930 | ||
5931 | ret = cpumask_parse(buf, cpumask); | |
5932 | if (!ret) | |
5933 | ret = workqueue_set_unbound_cpumask(cpumask); | |
5934 | ||
5935 | free_cpumask_var(cpumask); | |
5936 | return ret ? ret : count; | |
5937 | } | |
5938 | ||
b05a7928 | 5939 | static struct device_attribute wq_sysfs_cpumask_attr = |
042f7df1 LJ |
5940 | __ATTR(cpumask, 0644, wq_unbound_cpumask_show, |
5941 | wq_unbound_cpumask_store); | |
b05a7928 | 5942 | |
6ba94429 | 5943 | static int __init wq_sysfs_init(void) |
2d3854a3 | 5944 | { |
686f6697 | 5945 | struct device *dev_root; |
b05a7928 FW |
5946 | int err; |
5947 | ||
5948 | err = subsys_virtual_register(&wq_subsys, NULL); | |
5949 | if (err) | |
5950 | return err; | |
5951 | ||
686f6697 GKH |
5952 | dev_root = bus_get_dev_root(&wq_subsys); |
5953 | if (dev_root) { | |
5954 | err = device_create_file(dev_root, &wq_sysfs_cpumask_attr); | |
5955 | put_device(dev_root); | |
5956 | } | |
5957 | return err; | |
2d3854a3 | 5958 | } |
6ba94429 | 5959 | core_initcall(wq_sysfs_init); |
2d3854a3 | 5960 | |
6ba94429 | 5961 | static void wq_device_release(struct device *dev) |
2d3854a3 | 5962 | { |
6ba94429 | 5963 | struct wq_device *wq_dev = container_of(dev, struct wq_device, dev); |
6b44003e | 5964 | |
6ba94429 | 5965 | kfree(wq_dev); |
2d3854a3 | 5966 | } |
a0a1a5fd TH |
5967 | |
5968 | /** | |
6ba94429 FW |
5969 | * workqueue_sysfs_register - make a workqueue visible in sysfs |
5970 | * @wq: the workqueue to register | |
a0a1a5fd | 5971 | * |
6ba94429 FW |
5972 | * Expose @wq in sysfs under /sys/bus/workqueue/devices. |
5973 | * alloc_workqueue*() automatically calls this function if WQ_SYSFS is set | |
5974 | * which is the preferred method. | |
a0a1a5fd | 5975 | * |
6ba94429 FW |
5976 | * Workqueue user should use this function directly iff it wants to apply |
5977 | * workqueue_attrs before making the workqueue visible in sysfs; otherwise, | |
5978 | * apply_workqueue_attrs() may race against userland updating the | |
5979 | * attributes. | |
5980 | * | |
5981 | * Return: 0 on success, -errno on failure. | |
a0a1a5fd | 5982 | */ |
6ba94429 | 5983 | int workqueue_sysfs_register(struct workqueue_struct *wq) |
a0a1a5fd | 5984 | { |
6ba94429 FW |
5985 | struct wq_device *wq_dev; |
5986 | int ret; | |
a0a1a5fd | 5987 | |
6ba94429 | 5988 | /* |
402dd89d | 5989 | * Adjusting max_active or creating new pwqs by applying |
6ba94429 FW |
5990 | * attributes breaks ordering guarantee. Disallow exposing ordered |
5991 | * workqueues. | |
5992 | */ | |
0a94efb5 | 5993 | if (WARN_ON(wq->flags & __WQ_ORDERED_EXPLICIT)) |
6ba94429 | 5994 | return -EINVAL; |
a0a1a5fd | 5995 | |
6ba94429 FW |
5996 | wq->wq_dev = wq_dev = kzalloc(sizeof(*wq_dev), GFP_KERNEL); |
5997 | if (!wq_dev) | |
5998 | return -ENOMEM; | |
5bcab335 | 5999 | |
6ba94429 FW |
6000 | wq_dev->wq = wq; |
6001 | wq_dev->dev.bus = &wq_subsys; | |
6ba94429 | 6002 | wq_dev->dev.release = wq_device_release; |
23217b44 | 6003 | dev_set_name(&wq_dev->dev, "%s", wq->name); |
a0a1a5fd | 6004 | |
6ba94429 FW |
6005 | /* |
6006 | * unbound_attrs are created separately. Suppress uevent until | |
6007 | * everything is ready. | |
6008 | */ | |
6009 | dev_set_uevent_suppress(&wq_dev->dev, true); | |
a0a1a5fd | 6010 | |
6ba94429 FW |
6011 | ret = device_register(&wq_dev->dev); |
6012 | if (ret) { | |
537f4146 | 6013 | put_device(&wq_dev->dev); |
6ba94429 FW |
6014 | wq->wq_dev = NULL; |
6015 | return ret; | |
6016 | } | |
a0a1a5fd | 6017 | |
6ba94429 FW |
6018 | if (wq->flags & WQ_UNBOUND) { |
6019 | struct device_attribute *attr; | |
a0a1a5fd | 6020 | |
6ba94429 FW |
6021 | for (attr = wq_sysfs_unbound_attrs; attr->attr.name; attr++) { |
6022 | ret = device_create_file(&wq_dev->dev, attr); | |
6023 | if (ret) { | |
6024 | device_unregister(&wq_dev->dev); | |
6025 | wq->wq_dev = NULL; | |
6026 | return ret; | |
a0a1a5fd TH |
6027 | } |
6028 | } | |
6029 | } | |
6ba94429 FW |
6030 | |
6031 | dev_set_uevent_suppress(&wq_dev->dev, false); | |
6032 | kobject_uevent(&wq_dev->dev.kobj, KOBJ_ADD); | |
6033 | return 0; | |
a0a1a5fd TH |
6034 | } |
6035 | ||
6036 | /** | |
6ba94429 FW |
6037 | * workqueue_sysfs_unregister - undo workqueue_sysfs_register() |
6038 | * @wq: the workqueue to unregister | |
a0a1a5fd | 6039 | * |
6ba94429 | 6040 | * If @wq is registered to sysfs by workqueue_sysfs_register(), unregister. |
a0a1a5fd | 6041 | */ |
6ba94429 | 6042 | static void workqueue_sysfs_unregister(struct workqueue_struct *wq) |
a0a1a5fd | 6043 | { |
6ba94429 | 6044 | struct wq_device *wq_dev = wq->wq_dev; |
8b03ae3c | 6045 | |
6ba94429 FW |
6046 | if (!wq->wq_dev) |
6047 | return; | |
a0a1a5fd | 6048 | |
6ba94429 FW |
6049 | wq->wq_dev = NULL; |
6050 | device_unregister(&wq_dev->dev); | |
a0a1a5fd | 6051 | } |
6ba94429 FW |
6052 | #else /* CONFIG_SYSFS */ |
6053 | static void workqueue_sysfs_unregister(struct workqueue_struct *wq) { } | |
6054 | #endif /* CONFIG_SYSFS */ | |
a0a1a5fd | 6055 | |
82607adc TH |
6056 | /* |
6057 | * Workqueue watchdog. | |
6058 | * | |
6059 | * Stall may be caused by various bugs - missing WQ_MEM_RECLAIM, illegal | |
6060 | * flush dependency, a concurrency managed work item which stays RUNNING | |
6061 | * indefinitely. Workqueue stalls can be very difficult to debug as the | |
6062 | * usual warning mechanisms don't trigger and internal workqueue state is | |
6063 | * largely opaque. | |
6064 | * | |
6065 | * Workqueue watchdog monitors all worker pools periodically and dumps | |
6066 | * state if some pools failed to make forward progress for a while where | |
6067 | * forward progress is defined as the first item on ->worklist changing. | |
6068 | * | |
6069 | * This mechanism is controlled through the kernel parameter | |
6070 | * "workqueue.watchdog_thresh" which can be updated at runtime through the | |
6071 | * corresponding sysfs parameter file. | |
6072 | */ | |
6073 | #ifdef CONFIG_WQ_WATCHDOG | |
6074 | ||
82607adc | 6075 | static unsigned long wq_watchdog_thresh = 30; |
5cd79d6a | 6076 | static struct timer_list wq_watchdog_timer; |
82607adc TH |
6077 | |
6078 | static unsigned long wq_watchdog_touched = INITIAL_JIFFIES; | |
6079 | static DEFINE_PER_CPU(unsigned long, wq_watchdog_touched_cpu) = INITIAL_JIFFIES; | |
6080 | ||
cd2440d6 PM |
6081 | /* |
6082 | * Show workers that might prevent the processing of pending work items. | |
6083 | * The only candidates are CPU-bound workers in the running state. | |
6084 | * Pending work items should be handled by another idle worker | |
6085 | * in all other situations. | |
6086 | */ | |
6087 | static void show_cpu_pool_hog(struct worker_pool *pool) | |
6088 | { | |
6089 | struct worker *worker; | |
6090 | unsigned long flags; | |
6091 | int bkt; | |
6092 | ||
6093 | raw_spin_lock_irqsave(&pool->lock, flags); | |
6094 | ||
6095 | hash_for_each(pool->busy_hash, bkt, worker, hentry) { | |
6096 | if (task_is_running(worker->task)) { | |
6097 | /* | |
6098 | * Defer printing to avoid deadlocks in console | |
6099 | * drivers that queue work while holding locks | |
6100 | * also taken in their write paths. | |
6101 | */ | |
6102 | printk_deferred_enter(); | |
6103 | ||
6104 | pr_info("pool %d:\n", pool->id); | |
6105 | sched_show_task(worker->task); | |
6106 | ||
6107 | printk_deferred_exit(); | |
6108 | } | |
6109 | } | |
6110 | ||
6111 | raw_spin_unlock_irqrestore(&pool->lock, flags); | |
6112 | } | |
6113 | ||
6114 | static void show_cpu_pools_hogs(void) | |
6115 | { | |
6116 | struct worker_pool *pool; | |
6117 | int pi; | |
6118 | ||
6119 | pr_info("Showing backtraces of running workers in stalled CPU-bound worker pools:\n"); | |
6120 | ||
6121 | rcu_read_lock(); | |
6122 | ||
6123 | for_each_pool(pool, pi) { | |
6124 | if (pool->cpu_stall) | |
6125 | show_cpu_pool_hog(pool); | |
6126 | ||
6127 | } | |
6128 | ||
6129 | rcu_read_unlock(); | |
6130 | } | |
6131 | ||
82607adc TH |
6132 | static void wq_watchdog_reset_touched(void) |
6133 | { | |
6134 | int cpu; | |
6135 | ||
6136 | wq_watchdog_touched = jiffies; | |
6137 | for_each_possible_cpu(cpu) | |
6138 | per_cpu(wq_watchdog_touched_cpu, cpu) = jiffies; | |
6139 | } | |
6140 | ||
5cd79d6a | 6141 | static void wq_watchdog_timer_fn(struct timer_list *unused) |
82607adc TH |
6142 | { |
6143 | unsigned long thresh = READ_ONCE(wq_watchdog_thresh) * HZ; | |
6144 | bool lockup_detected = false; | |
cd2440d6 | 6145 | bool cpu_pool_stall = false; |
940d71c6 | 6146 | unsigned long now = jiffies; |
82607adc TH |
6147 | struct worker_pool *pool; |
6148 | int pi; | |
6149 | ||
6150 | if (!thresh) | |
6151 | return; | |
6152 | ||
6153 | rcu_read_lock(); | |
6154 | ||
6155 | for_each_pool(pool, pi) { | |
6156 | unsigned long pool_ts, touched, ts; | |
6157 | ||
cd2440d6 | 6158 | pool->cpu_stall = false; |
82607adc TH |
6159 | if (list_empty(&pool->worklist)) |
6160 | continue; | |
6161 | ||
940d71c6 SS |
6162 | /* |
6163 | * If a virtual machine is stopped by the host it can look to | |
6164 | * the watchdog like a stall. | |
6165 | */ | |
6166 | kvm_check_and_clear_guest_paused(); | |
6167 | ||
82607adc | 6168 | /* get the latest of pool and touched timestamps */ |
89e28ce6 WQ |
6169 | if (pool->cpu >= 0) |
6170 | touched = READ_ONCE(per_cpu(wq_watchdog_touched_cpu, pool->cpu)); | |
6171 | else | |
6172 | touched = READ_ONCE(wq_watchdog_touched); | |
82607adc | 6173 | pool_ts = READ_ONCE(pool->watchdog_ts); |
82607adc TH |
6174 | |
6175 | if (time_after(pool_ts, touched)) | |
6176 | ts = pool_ts; | |
6177 | else | |
6178 | ts = touched; | |
6179 | ||
82607adc | 6180 | /* did we stall? */ |
940d71c6 | 6181 | if (time_after(now, ts + thresh)) { |
82607adc | 6182 | lockup_detected = true; |
cd2440d6 PM |
6183 | if (pool->cpu >= 0) { |
6184 | pool->cpu_stall = true; | |
6185 | cpu_pool_stall = true; | |
6186 | } | |
82607adc TH |
6187 | pr_emerg("BUG: workqueue lockup - pool"); |
6188 | pr_cont_pool_info(pool); | |
6189 | pr_cont(" stuck for %us!\n", | |
940d71c6 | 6190 | jiffies_to_msecs(now - pool_ts) / 1000); |
82607adc | 6191 | } |
cd2440d6 PM |
6192 | |
6193 | ||
82607adc TH |
6194 | } |
6195 | ||
6196 | rcu_read_unlock(); | |
6197 | ||
6198 | if (lockup_detected) | |
55df0933 | 6199 | show_all_workqueues(); |
82607adc | 6200 | |
cd2440d6 PM |
6201 | if (cpu_pool_stall) |
6202 | show_cpu_pools_hogs(); | |
6203 | ||
82607adc TH |
6204 | wq_watchdog_reset_touched(); |
6205 | mod_timer(&wq_watchdog_timer, jiffies + thresh); | |
6206 | } | |
6207 | ||
cb9d7fd5 | 6208 | notrace void wq_watchdog_touch(int cpu) |
82607adc TH |
6209 | { |
6210 | if (cpu >= 0) | |
6211 | per_cpu(wq_watchdog_touched_cpu, cpu) = jiffies; | |
89e28ce6 WQ |
6212 | |
6213 | wq_watchdog_touched = jiffies; | |
82607adc TH |
6214 | } |
6215 | ||
6216 | static void wq_watchdog_set_thresh(unsigned long thresh) | |
6217 | { | |
6218 | wq_watchdog_thresh = 0; | |
6219 | del_timer_sync(&wq_watchdog_timer); | |
6220 | ||
6221 | if (thresh) { | |
6222 | wq_watchdog_thresh = thresh; | |
6223 | wq_watchdog_reset_touched(); | |
6224 | mod_timer(&wq_watchdog_timer, jiffies + thresh * HZ); | |
6225 | } | |
6226 | } | |
6227 | ||
6228 | static int wq_watchdog_param_set_thresh(const char *val, | |
6229 | const struct kernel_param *kp) | |
6230 | { | |
6231 | unsigned long thresh; | |
6232 | int ret; | |
6233 | ||
6234 | ret = kstrtoul(val, 0, &thresh); | |
6235 | if (ret) | |
6236 | return ret; | |
6237 | ||
6238 | if (system_wq) | |
6239 | wq_watchdog_set_thresh(thresh); | |
6240 | else | |
6241 | wq_watchdog_thresh = thresh; | |
6242 | ||
6243 | return 0; | |
6244 | } | |
6245 | ||
6246 | static const struct kernel_param_ops wq_watchdog_thresh_ops = { | |
6247 | .set = wq_watchdog_param_set_thresh, | |
6248 | .get = param_get_ulong, | |
6249 | }; | |
6250 | ||
6251 | module_param_cb(watchdog_thresh, &wq_watchdog_thresh_ops, &wq_watchdog_thresh, | |
6252 | 0644); | |
6253 | ||
6254 | static void wq_watchdog_init(void) | |
6255 | { | |
5cd79d6a | 6256 | timer_setup(&wq_watchdog_timer, wq_watchdog_timer_fn, TIMER_DEFERRABLE); |
82607adc TH |
6257 | wq_watchdog_set_thresh(wq_watchdog_thresh); |
6258 | } | |
6259 | ||
6260 | #else /* CONFIG_WQ_WATCHDOG */ | |
6261 | ||
6262 | static inline void wq_watchdog_init(void) { } | |
6263 | ||
6264 | #endif /* CONFIG_WQ_WATCHDOG */ | |
6265 | ||
3347fa09 TH |
6266 | /** |
6267 | * workqueue_init_early - early init for workqueue subsystem | |
6268 | * | |
2930155b TH |
6269 | * This is the first step of three-staged workqueue subsystem initialization and |
6270 | * invoked as soon as the bare basics - memory allocation, cpumasks and idr are | |
6271 | * up. It sets up all the data structures and system workqueues and allows early | |
6272 | * boot code to create workqueues and queue/cancel work items. Actual work item | |
6273 | * execution starts only after kthreads can be created and scheduled right | |
6274 | * before early initcalls. | |
3347fa09 | 6275 | */ |
2333e829 | 6276 | void __init workqueue_init_early(void) |
1da177e4 | 6277 | { |
7a4e344c TH |
6278 | int std_nice[NR_STD_WORKER_POOLS] = { 0, HIGHPRI_NICE_LEVEL }; |
6279 | int i, cpu; | |
c34056a3 | 6280 | |
10cdb157 | 6281 | BUILD_BUG_ON(__alignof__(struct pool_workqueue) < __alignof__(long long)); |
e904e6c2 | 6282 | |
b05a7928 | 6283 | BUG_ON(!alloc_cpumask_var(&wq_unbound_cpumask, GFP_KERNEL)); |
04d4e665 FW |
6284 | cpumask_copy(wq_unbound_cpumask, housekeeping_cpumask(HK_TYPE_WQ)); |
6285 | cpumask_and(wq_unbound_cpumask, wq_unbound_cpumask, housekeeping_cpumask(HK_TYPE_DOMAIN)); | |
b05a7928 | 6286 | |
ace3c549 | 6287 | if (!cpumask_empty(&wq_cmdline_cpumask)) |
6288 | cpumask_and(wq_unbound_cpumask, wq_unbound_cpumask, &wq_cmdline_cpumask); | |
6289 | ||
e904e6c2 TH |
6290 | pwq_cache = KMEM_CACHE(pool_workqueue, SLAB_PANIC); |
6291 | ||
2930155b TH |
6292 | wq_update_pod_attrs_buf = alloc_workqueue_attrs(); |
6293 | BUG_ON(!wq_update_pod_attrs_buf); | |
6294 | ||
0f36ee24 TH |
6295 | BUG_ON(!alloc_cpumask_var(&wq_update_pod_cpumask_buf, GFP_KERNEL)); |
6296 | ||
706026c2 | 6297 | /* initialize CPU pools */ |
29c91e99 | 6298 | for_each_possible_cpu(cpu) { |
4ce62e9e | 6299 | struct worker_pool *pool; |
8b03ae3c | 6300 | |
7a4e344c | 6301 | i = 0; |
f02ae73a | 6302 | for_each_cpu_worker_pool(pool, cpu) { |
7a4e344c | 6303 | BUG_ON(init_worker_pool(pool)); |
ec22ca5e | 6304 | pool->cpu = cpu; |
29c91e99 | 6305 | cpumask_copy(pool->attrs->cpumask, cpumask_of(cpu)); |
7a4e344c | 6306 | pool->attrs->nice = std_nice[i++]; |
f3f90ad4 | 6307 | pool->node = cpu_to_node(cpu); |
7a4e344c | 6308 | |
9daf9e67 | 6309 | /* alloc pool ID */ |
68e13a67 | 6310 | mutex_lock(&wq_pool_mutex); |
9daf9e67 | 6311 | BUG_ON(worker_pool_assign_id(pool)); |
68e13a67 | 6312 | mutex_unlock(&wq_pool_mutex); |
4ce62e9e | 6313 | } |
8b03ae3c TH |
6314 | } |
6315 | ||
8a2b7538 | 6316 | /* create default unbound and ordered wq attrs */ |
29c91e99 TH |
6317 | for (i = 0; i < NR_STD_WORKER_POOLS; i++) { |
6318 | struct workqueue_attrs *attrs; | |
6319 | ||
be69d00d | 6320 | BUG_ON(!(attrs = alloc_workqueue_attrs())); |
29c91e99 | 6321 | attrs->nice = std_nice[i]; |
29c91e99 | 6322 | unbound_std_wq_attrs[i] = attrs; |
8a2b7538 TH |
6323 | |
6324 | /* | |
6325 | * An ordered wq should have only one pwq as ordering is | |
6326 | * guaranteed by max_active which is enforced by pwqs. | |
8a2b7538 | 6327 | */ |
be69d00d | 6328 | BUG_ON(!(attrs = alloc_workqueue_attrs())); |
8a2b7538 | 6329 | attrs->nice = std_nice[i]; |
af73f5c9 | 6330 | attrs->ordered = true; |
8a2b7538 | 6331 | ordered_wq_attrs[i] = attrs; |
29c91e99 TH |
6332 | } |
6333 | ||
d320c038 | 6334 | system_wq = alloc_workqueue("events", 0, 0); |
1aabe902 | 6335 | system_highpri_wq = alloc_workqueue("events_highpri", WQ_HIGHPRI, 0); |
d320c038 | 6336 | system_long_wq = alloc_workqueue("events_long", 0, 0); |
f3421797 | 6337 | system_unbound_wq = alloc_workqueue("events_unbound", WQ_UNBOUND, |
636b927e | 6338 | WQ_MAX_ACTIVE); |
24d51add TH |
6339 | system_freezable_wq = alloc_workqueue("events_freezable", |
6340 | WQ_FREEZABLE, 0); | |
0668106c VK |
6341 | system_power_efficient_wq = alloc_workqueue("events_power_efficient", |
6342 | WQ_POWER_EFFICIENT, 0); | |
6343 | system_freezable_power_efficient_wq = alloc_workqueue("events_freezable_power_efficient", | |
6344 | WQ_FREEZABLE | WQ_POWER_EFFICIENT, | |
6345 | 0); | |
1aabe902 | 6346 | BUG_ON(!system_wq || !system_highpri_wq || !system_long_wq || |
0668106c VK |
6347 | !system_unbound_wq || !system_freezable_wq || |
6348 | !system_power_efficient_wq || | |
6349 | !system_freezable_power_efficient_wq); | |
3347fa09 TH |
6350 | } |
6351 | ||
aa6fde93 TH |
6352 | static void __init wq_cpu_intensive_thresh_init(void) |
6353 | { | |
6354 | unsigned long thresh; | |
6355 | unsigned long bogo; | |
6356 | ||
6357 | /* if the user set it to a specific value, keep it */ | |
6358 | if (wq_cpu_intensive_thresh_us != ULONG_MAX) | |
6359 | return; | |
6360 | ||
967b494e TH |
6361 | pwq_release_worker = kthread_create_worker(0, "pool_workqueue_release"); |
6362 | BUG_ON(IS_ERR(pwq_release_worker)); | |
6363 | ||
aa6fde93 TH |
6364 | /* |
6365 | * The default of 10ms is derived from the fact that most modern (as of | |
6366 | * 2023) processors can do a lot in 10ms and that it's just below what | |
6367 | * most consider human-perceivable. However, the kernel also runs on a | |
6368 | * lot slower CPUs including microcontrollers where the threshold is way | |
6369 | * too low. | |
6370 | * | |
6371 | * Let's scale up the threshold upto 1 second if BogoMips is below 4000. | |
6372 | * This is by no means accurate but it doesn't have to be. The mechanism | |
6373 | * is still useful even when the threshold is fully scaled up. Also, as | |
6374 | * the reports would usually be applicable to everyone, some machines | |
6375 | * operating on longer thresholds won't significantly diminish their | |
6376 | * usefulness. | |
6377 | */ | |
6378 | thresh = 10 * USEC_PER_MSEC; | |
6379 | ||
6380 | /* see init/calibrate.c for lpj -> BogoMIPS calculation */ | |
6381 | bogo = max_t(unsigned long, loops_per_jiffy / 500000 * HZ, 1); | |
6382 | if (bogo < 4000) | |
6383 | thresh = min_t(unsigned long, thresh * 4000 / bogo, USEC_PER_SEC); | |
6384 | ||
6385 | pr_debug("wq_cpu_intensive_thresh: lpj=%lu BogoMIPS=%lu thresh_us=%lu\n", | |
6386 | loops_per_jiffy, bogo, thresh); | |
6387 | ||
6388 | wq_cpu_intensive_thresh_us = thresh; | |
6389 | } | |
6390 | ||
3347fa09 TH |
6391 | /** |
6392 | * workqueue_init - bring workqueue subsystem fully online | |
6393 | * | |
2930155b TH |
6394 | * This is the second step of three-staged workqueue subsystem initialization |
6395 | * and invoked as soon as kthreads can be created and scheduled. Workqueues have | |
6396 | * been created and work items queued on them, but there are no kworkers | |
6397 | * executing the work items yet. Populate the worker pools with the initial | |
6398 | * workers and enable future kworker creations. | |
3347fa09 | 6399 | */ |
2333e829 | 6400 | void __init workqueue_init(void) |
3347fa09 | 6401 | { |
2186d9f9 | 6402 | struct workqueue_struct *wq; |
3347fa09 TH |
6403 | struct worker_pool *pool; |
6404 | int cpu, bkt; | |
6405 | ||
aa6fde93 TH |
6406 | wq_cpu_intensive_thresh_init(); |
6407 | ||
2186d9f9 TH |
6408 | mutex_lock(&wq_pool_mutex); |
6409 | ||
2930155b TH |
6410 | /* |
6411 | * Per-cpu pools created earlier could be missing node hint. Fix them | |
6412 | * up. Also, create a rescuer for workqueues that requested it. | |
6413 | */ | |
2186d9f9 TH |
6414 | for_each_possible_cpu(cpu) { |
6415 | for_each_cpu_worker_pool(pool, cpu) { | |
6416 | pool->node = cpu_to_node(cpu); | |
6417 | } | |
6418 | } | |
6419 | ||
40c17f75 | 6420 | list_for_each_entry(wq, &workqueues, list) { |
40c17f75 TH |
6421 | WARN(init_rescuer(wq), |
6422 | "workqueue: failed to create early rescuer for %s", | |
6423 | wq->name); | |
6424 | } | |
2186d9f9 TH |
6425 | |
6426 | mutex_unlock(&wq_pool_mutex); | |
6427 | ||
3347fa09 TH |
6428 | /* create the initial workers */ |
6429 | for_each_online_cpu(cpu) { | |
6430 | for_each_cpu_worker_pool(pool, cpu) { | |
6431 | pool->flags &= ~POOL_DISASSOCIATED; | |
6432 | BUG_ON(!create_worker(pool)); | |
6433 | } | |
6434 | } | |
6435 | ||
6436 | hash_for_each(unbound_pool_hash, bkt, pool, hash_node) | |
6437 | BUG_ON(!create_worker(pool)); | |
6438 | ||
6439 | wq_online = true; | |
82607adc | 6440 | wq_watchdog_init(); |
1da177e4 | 6441 | } |
c4f135d6 | 6442 | |
2930155b TH |
6443 | /** |
6444 | * workqueue_init_topology - initialize CPU pods for unbound workqueues | |
6445 | * | |
6446 | * This is the third step of there-staged workqueue subsystem initialization and | |
6447 | * invoked after SMP and topology information are fully initialized. It | |
6448 | * initializes the unbound CPU pods accordingly. | |
6449 | */ | |
6450 | void __init workqueue_init_topology(void) | |
a86feae6 | 6451 | { |
2930155b | 6452 | struct workqueue_struct *wq; |
a86feae6 TH |
6453 | cpumask_var_t *tbl; |
6454 | int node, cpu; | |
6455 | ||
6456 | if (num_possible_nodes() <= 1) | |
6457 | return; | |
6458 | ||
6459 | for_each_possible_cpu(cpu) { | |
6460 | if (WARN_ON(cpu_to_node(cpu) == NUMA_NO_NODE)) { | |
6461 | pr_warn("workqueue: NUMA node mapping not available for cpu%d, disabling NUMA support\n", cpu); | |
6462 | return; | |
6463 | } | |
6464 | } | |
6465 | ||
2930155b | 6466 | mutex_lock(&wq_pool_mutex); |
a86feae6 TH |
6467 | |
6468 | /* | |
6469 | * We want masks of possible CPUs of each node which isn't readily | |
6470 | * available. Build one from cpu_to_node() which should have been | |
6471 | * fully initialized by now. | |
6472 | */ | |
6473 | tbl = kcalloc(nr_node_ids, sizeof(tbl[0]), GFP_KERNEL); | |
6474 | BUG_ON(!tbl); | |
6475 | ||
6476 | for_each_node(node) | |
6477 | BUG_ON(!zalloc_cpumask_var_node(&tbl[node], GFP_KERNEL, | |
6478 | node_online(node) ? node : NUMA_NO_NODE)); | |
6479 | ||
6480 | for_each_possible_cpu(cpu) { | |
6481 | node = cpu_to_node(cpu); | |
6482 | cpumask_set_cpu(cpu, tbl[node]); | |
6483 | } | |
6484 | ||
6485 | wq_pod_cpus = tbl; | |
6486 | wq_pod_enabled = true; | |
2930155b TH |
6487 | |
6488 | /* | |
6489 | * Workqueues allocated earlier would have all CPUs sharing the default | |
6490 | * worker pool. Explicitly call wq_update_pod() on all workqueue and CPU | |
6491 | * combinations to apply per-pod sharing. | |
6492 | */ | |
6493 | list_for_each_entry(wq, &workqueues, list) { | |
6494 | for_each_online_cpu(cpu) { | |
6495 | wq_update_pod(wq, cpu, cpu, true); | |
6496 | } | |
6497 | } | |
6498 | ||
6499 | mutex_unlock(&wq_pool_mutex); | |
a86feae6 TH |
6500 | } |
6501 | ||
20bdedaf TH |
6502 | void __warn_flushing_systemwide_wq(void) |
6503 | { | |
6504 | pr_warn("WARNING: Flushing system-wide workqueues will be prohibited in near future.\n"); | |
6505 | dump_stack(); | |
6506 | } | |
c4f135d6 | 6507 | EXPORT_SYMBOL(__warn_flushing_systemwide_wq); |
ace3c549 | 6508 | |
6509 | static int __init workqueue_unbound_cpus_setup(char *str) | |
6510 | { | |
6511 | if (cpulist_parse(str, &wq_cmdline_cpumask) < 0) { | |
6512 | cpumask_clear(&wq_cmdline_cpumask); | |
6513 | pr_warn("workqueue.unbound_cpus: incorrect CPU range, using default\n"); | |
6514 | } | |
6515 | ||
6516 | return 1; | |
6517 | } | |
6518 | __setup("workqueue.unbound_cpus=", workqueue_unbound_cpus_setup); |