Commit | Line | Data |
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1da177e4 | 1 | /* |
c54fce6e | 2 | * kernel/workqueue.c - generic async execution with shared worker pool |
1da177e4 | 3 | * |
c54fce6e | 4 | * Copyright (C) 2002 Ingo Molnar |
1da177e4 | 5 | * |
c54fce6e TH |
6 | * Derived from the taskqueue/keventd code by: |
7 | * David Woodhouse <dwmw2@infradead.org> | |
8 | * Andrew Morton | |
9 | * Kai Petzke <wpp@marie.physik.tu-berlin.de> | |
10 | * Theodore Ts'o <tytso@mit.edu> | |
1da177e4 | 11 | * |
c54fce6e | 12 | * Made to use alloc_percpu by Christoph Lameter. |
1da177e4 | 13 | * |
c54fce6e TH |
14 | * Copyright (C) 2010 SUSE Linux Products GmbH |
15 | * Copyright (C) 2010 Tejun Heo <tj@kernel.org> | |
89ada679 | 16 | * |
c54fce6e TH |
17 | * This is the generic async execution mechanism. Work items as are |
18 | * executed in process context. The worker pool is shared and | |
19 | * automatically managed. There is one worker pool for each CPU and | |
20 | * one extra for works which are better served by workers which are | |
21 | * not bound to any specific CPU. | |
22 | * | |
23 | * Please read Documentation/workqueue.txt for details. | |
1da177e4 LT |
24 | */ |
25 | ||
9984de1a | 26 | #include <linux/export.h> |
1da177e4 LT |
27 | #include <linux/kernel.h> |
28 | #include <linux/sched.h> | |
29 | #include <linux/init.h> | |
30 | #include <linux/signal.h> | |
31 | #include <linux/completion.h> | |
32 | #include <linux/workqueue.h> | |
33 | #include <linux/slab.h> | |
34 | #include <linux/cpu.h> | |
35 | #include <linux/notifier.h> | |
36 | #include <linux/kthread.h> | |
1fa44eca | 37 | #include <linux/hardirq.h> |
46934023 | 38 | #include <linux/mempolicy.h> |
341a5958 | 39 | #include <linux/freezer.h> |
d5abe669 PZ |
40 | #include <linux/kallsyms.h> |
41 | #include <linux/debug_locks.h> | |
4e6045f1 | 42 | #include <linux/lockdep.h> |
c34056a3 | 43 | #include <linux/idr.h> |
42f8570f | 44 | #include <linux/hashtable.h> |
e22bee78 | 45 | |
ea138446 | 46 | #include "workqueue_internal.h" |
1da177e4 | 47 | |
c8e55f36 | 48 | enum { |
24647570 TH |
49 | /* |
50 | * worker_pool flags | |
bc2ae0f5 | 51 | * |
24647570 | 52 | * A bound pool is either associated or disassociated with its CPU. |
bc2ae0f5 TH |
53 | * While associated (!DISASSOCIATED), all workers are bound to the |
54 | * CPU and none has %WORKER_UNBOUND set and concurrency management | |
55 | * is in effect. | |
56 | * | |
57 | * While DISASSOCIATED, the cpu may be offline and all workers have | |
58 | * %WORKER_UNBOUND set and concurrency management disabled, and may | |
24647570 | 59 | * be executing on any CPU. The pool behaves as an unbound one. |
bc2ae0f5 TH |
60 | * |
61 | * Note that DISASSOCIATED can be flipped only while holding | |
24647570 TH |
62 | * assoc_mutex to avoid changing binding state while |
63 | * create_worker() is in progress. | |
bc2ae0f5 | 64 | */ |
11ebea50 | 65 | POOL_MANAGE_WORKERS = 1 << 0, /* need to manage workers */ |
552a37e9 | 66 | POOL_MANAGING_WORKERS = 1 << 1, /* managing workers */ |
24647570 | 67 | POOL_DISASSOCIATED = 1 << 2, /* cpu can't serve workers */ |
35b6bb63 | 68 | POOL_FREEZING = 1 << 3, /* freeze in progress */ |
db7bccf4 | 69 | |
c8e55f36 TH |
70 | /* worker flags */ |
71 | WORKER_STARTED = 1 << 0, /* started */ | |
72 | WORKER_DIE = 1 << 1, /* die die die */ | |
73 | WORKER_IDLE = 1 << 2, /* is idle */ | |
e22bee78 | 74 | WORKER_PREP = 1 << 3, /* preparing to run works */ |
fb0e7beb | 75 | WORKER_CPU_INTENSIVE = 1 << 6, /* cpu intensive */ |
f3421797 | 76 | WORKER_UNBOUND = 1 << 7, /* worker is unbound */ |
e22bee78 | 77 | |
5f7dabfd | 78 | WORKER_NOT_RUNNING = WORKER_PREP | WORKER_UNBOUND | |
403c821d | 79 | WORKER_CPU_INTENSIVE, |
db7bccf4 | 80 | |
e34cdddb | 81 | NR_STD_WORKER_POOLS = 2, /* # standard pools per cpu */ |
4ce62e9e | 82 | |
c8e55f36 | 83 | BUSY_WORKER_HASH_ORDER = 6, /* 64 pointers */ |
db7bccf4 | 84 | |
e22bee78 TH |
85 | MAX_IDLE_WORKERS_RATIO = 4, /* 1/4 of busy can be idle */ |
86 | IDLE_WORKER_TIMEOUT = 300 * HZ, /* keep idle ones for 5 mins */ | |
87 | ||
3233cdbd TH |
88 | MAYDAY_INITIAL_TIMEOUT = HZ / 100 >= 2 ? HZ / 100 : 2, |
89 | /* call for help after 10ms | |
90 | (min two ticks) */ | |
e22bee78 TH |
91 | MAYDAY_INTERVAL = HZ / 10, /* and then every 100ms */ |
92 | CREATE_COOLDOWN = HZ, /* time to breath after fail */ | |
e22bee78 TH |
93 | |
94 | /* | |
95 | * Rescue workers are used only on emergencies and shared by | |
96 | * all cpus. Give -20. | |
97 | */ | |
98 | RESCUER_NICE_LEVEL = -20, | |
3270476a | 99 | HIGHPRI_NICE_LEVEL = -20, |
c8e55f36 | 100 | }; |
1da177e4 LT |
101 | |
102 | /* | |
4690c4ab TH |
103 | * Structure fields follow one of the following exclusion rules. |
104 | * | |
e41e704b TH |
105 | * I: Modifiable by initialization/destruction paths and read-only for |
106 | * everyone else. | |
4690c4ab | 107 | * |
e22bee78 TH |
108 | * P: Preemption protected. Disabling preemption is enough and should |
109 | * only be modified and accessed from the local cpu. | |
110 | * | |
d565ed63 | 111 | * L: pool->lock protected. Access with pool->lock held. |
4690c4ab | 112 | * |
d565ed63 TH |
113 | * X: During normal operation, modification requires pool->lock and should |
114 | * be done only from local cpu. Either disabling preemption on local | |
115 | * cpu or grabbing pool->lock is enough for read access. If | |
116 | * POOL_DISASSOCIATED is set, it's identical to L. | |
e22bee78 | 117 | * |
73f53c4a TH |
118 | * F: wq->flush_mutex protected. |
119 | * | |
4690c4ab | 120 | * W: workqueue_lock protected. |
1da177e4 | 121 | */ |
1da177e4 | 122 | |
2eaebdb3 | 123 | /* struct worker is defined in workqueue_internal.h */ |
c34056a3 | 124 | |
bd7bdd43 | 125 | struct worker_pool { |
d565ed63 | 126 | spinlock_t lock; /* the pool lock */ |
ec22ca5e | 127 | unsigned int cpu; /* I: the associated cpu */ |
9daf9e67 | 128 | int id; /* I: pool ID */ |
11ebea50 | 129 | unsigned int flags; /* X: flags */ |
bd7bdd43 TH |
130 | |
131 | struct list_head worklist; /* L: list of pending works */ | |
132 | int nr_workers; /* L: total number of workers */ | |
ea1abd61 LJ |
133 | |
134 | /* nr_idle includes the ones off idle_list for rebinding */ | |
bd7bdd43 TH |
135 | int nr_idle; /* L: currently idle ones */ |
136 | ||
137 | struct list_head idle_list; /* X: list of idle workers */ | |
138 | struct timer_list idle_timer; /* L: worker idle timeout */ | |
139 | struct timer_list mayday_timer; /* L: SOS timer for workers */ | |
140 | ||
c9e7cf27 TH |
141 | /* workers are chained either in busy_hash or idle_list */ |
142 | DECLARE_HASHTABLE(busy_hash, BUSY_WORKER_HASH_ORDER); | |
143 | /* L: hash of busy workers */ | |
144 | ||
24647570 | 145 | struct mutex assoc_mutex; /* protect POOL_DISASSOCIATED */ |
bd7bdd43 | 146 | struct ida worker_ida; /* L: for worker IDs */ |
8b03ae3c TH |
147 | } ____cacheline_aligned_in_smp; |
148 | ||
1da177e4 | 149 | /* |
502ca9d8 | 150 | * The per-CPU workqueue. The lower WORK_STRUCT_FLAG_BITS of |
0f900049 TH |
151 | * work_struct->data are used for flags and thus cwqs need to be |
152 | * aligned at two's power of the number of flag bits. | |
1da177e4 LT |
153 | */ |
154 | struct cpu_workqueue_struct { | |
bd7bdd43 | 155 | struct worker_pool *pool; /* I: the associated pool */ |
4690c4ab | 156 | struct workqueue_struct *wq; /* I: the owning workqueue */ |
73f53c4a TH |
157 | int work_color; /* L: current color */ |
158 | int flush_color; /* L: flushing color */ | |
159 | int nr_in_flight[WORK_NR_COLORS]; | |
160 | /* L: nr of in_flight works */ | |
1e19ffc6 | 161 | int nr_active; /* L: nr of active works */ |
a0a1a5fd | 162 | int max_active; /* L: max active works */ |
1e19ffc6 | 163 | struct list_head delayed_works; /* L: delayed works */ |
0f900049 | 164 | }; |
1da177e4 | 165 | |
73f53c4a TH |
166 | /* |
167 | * Structure used to wait for workqueue flush. | |
168 | */ | |
169 | struct wq_flusher { | |
170 | struct list_head list; /* F: list of flushers */ | |
171 | int flush_color; /* F: flush color waiting for */ | |
172 | struct completion done; /* flush completion */ | |
173 | }; | |
174 | ||
f2e005aa TH |
175 | /* |
176 | * All cpumasks are assumed to be always set on UP and thus can't be | |
177 | * used to determine whether there's something to be done. | |
178 | */ | |
179 | #ifdef CONFIG_SMP | |
180 | typedef cpumask_var_t mayday_mask_t; | |
181 | #define mayday_test_and_set_cpu(cpu, mask) \ | |
182 | cpumask_test_and_set_cpu((cpu), (mask)) | |
183 | #define mayday_clear_cpu(cpu, mask) cpumask_clear_cpu((cpu), (mask)) | |
184 | #define for_each_mayday_cpu(cpu, mask) for_each_cpu((cpu), (mask)) | |
9c37547a | 185 | #define alloc_mayday_mask(maskp, gfp) zalloc_cpumask_var((maskp), (gfp)) |
f2e005aa TH |
186 | #define free_mayday_mask(mask) free_cpumask_var((mask)) |
187 | #else | |
188 | typedef unsigned long mayday_mask_t; | |
189 | #define mayday_test_and_set_cpu(cpu, mask) test_and_set_bit(0, &(mask)) | |
190 | #define mayday_clear_cpu(cpu, mask) clear_bit(0, &(mask)) | |
191 | #define for_each_mayday_cpu(cpu, mask) if ((cpu) = 0, (mask)) | |
192 | #define alloc_mayday_mask(maskp, gfp) true | |
193 | #define free_mayday_mask(mask) do { } while (0) | |
194 | #endif | |
1da177e4 LT |
195 | |
196 | /* | |
197 | * The externally visible workqueue abstraction is an array of | |
198 | * per-CPU workqueues: | |
199 | */ | |
200 | struct workqueue_struct { | |
9c5a2ba7 | 201 | unsigned int flags; /* W: WQ_* flags */ |
bdbc5dd7 TH |
202 | union { |
203 | struct cpu_workqueue_struct __percpu *pcpu; | |
204 | struct cpu_workqueue_struct *single; | |
205 | unsigned long v; | |
206 | } cpu_wq; /* I: cwq's */ | |
4690c4ab | 207 | struct list_head list; /* W: list of all workqueues */ |
73f53c4a TH |
208 | |
209 | struct mutex flush_mutex; /* protects wq flushing */ | |
210 | int work_color; /* F: current work color */ | |
211 | int flush_color; /* F: current flush color */ | |
212 | atomic_t nr_cwqs_to_flush; /* flush in progress */ | |
213 | struct wq_flusher *first_flusher; /* F: first flusher */ | |
214 | struct list_head flusher_queue; /* F: flush waiters */ | |
215 | struct list_head flusher_overflow; /* F: flush overflow list */ | |
216 | ||
f2e005aa | 217 | mayday_mask_t mayday_mask; /* cpus requesting rescue */ |
e22bee78 TH |
218 | struct worker *rescuer; /* I: rescue worker */ |
219 | ||
9c5a2ba7 | 220 | int nr_drainers; /* W: drain in progress */ |
dcd989cb | 221 | int saved_max_active; /* W: saved cwq max_active */ |
4e6045f1 | 222 | #ifdef CONFIG_LOCKDEP |
4690c4ab | 223 | struct lockdep_map lockdep_map; |
4e6045f1 | 224 | #endif |
b196be89 | 225 | char name[]; /* I: workqueue name */ |
1da177e4 LT |
226 | }; |
227 | ||
d320c038 | 228 | struct workqueue_struct *system_wq __read_mostly; |
d320c038 | 229 | EXPORT_SYMBOL_GPL(system_wq); |
044c782c | 230 | struct workqueue_struct *system_highpri_wq __read_mostly; |
1aabe902 | 231 | EXPORT_SYMBOL_GPL(system_highpri_wq); |
044c782c | 232 | struct workqueue_struct *system_long_wq __read_mostly; |
d320c038 | 233 | EXPORT_SYMBOL_GPL(system_long_wq); |
044c782c | 234 | struct workqueue_struct *system_unbound_wq __read_mostly; |
f3421797 | 235 | EXPORT_SYMBOL_GPL(system_unbound_wq); |
044c782c | 236 | struct workqueue_struct *system_freezable_wq __read_mostly; |
24d51add | 237 | EXPORT_SYMBOL_GPL(system_freezable_wq); |
d320c038 | 238 | |
97bd2347 TH |
239 | #define CREATE_TRACE_POINTS |
240 | #include <trace/events/workqueue.h> | |
241 | ||
38db41d9 | 242 | #define for_each_std_worker_pool(pool, cpu) \ |
a60dc39c TH |
243 | for ((pool) = &std_worker_pools(cpu)[0]; \ |
244 | (pool) < &std_worker_pools(cpu)[NR_STD_WORKER_POOLS]; (pool)++) | |
4ce62e9e | 245 | |
c9e7cf27 TH |
246 | #define for_each_busy_worker(worker, i, pos, pool) \ |
247 | hash_for_each(pool->busy_hash, i, pos, worker, hentry) | |
db7bccf4 | 248 | |
706026c2 TH |
249 | static inline int __next_wq_cpu(int cpu, const struct cpumask *mask, |
250 | unsigned int sw) | |
f3421797 TH |
251 | { |
252 | if (cpu < nr_cpu_ids) { | |
253 | if (sw & 1) { | |
254 | cpu = cpumask_next(cpu, mask); | |
255 | if (cpu < nr_cpu_ids) | |
256 | return cpu; | |
257 | } | |
258 | if (sw & 2) | |
259 | return WORK_CPU_UNBOUND; | |
260 | } | |
6be19588 | 261 | return WORK_CPU_END; |
f3421797 TH |
262 | } |
263 | ||
706026c2 TH |
264 | static inline int __next_cwq_cpu(int cpu, const struct cpumask *mask, |
265 | struct workqueue_struct *wq) | |
f3421797 | 266 | { |
706026c2 | 267 | return __next_wq_cpu(cpu, mask, !(wq->flags & WQ_UNBOUND) ? 1 : 2); |
f3421797 TH |
268 | } |
269 | ||
09884951 TH |
270 | /* |
271 | * CPU iterators | |
272 | * | |
706026c2 | 273 | * An extra cpu number is defined using an invalid cpu number |
09884951 | 274 | * (WORK_CPU_UNBOUND) to host workqueues which are not bound to any |
706026c2 TH |
275 | * specific CPU. The following iterators are similar to for_each_*_cpu() |
276 | * iterators but also considers the unbound CPU. | |
09884951 | 277 | * |
706026c2 TH |
278 | * for_each_wq_cpu() : possible CPUs + WORK_CPU_UNBOUND |
279 | * for_each_online_wq_cpu() : online CPUs + WORK_CPU_UNBOUND | |
09884951 TH |
280 | * for_each_cwq_cpu() : possible CPUs for bound workqueues, |
281 | * WORK_CPU_UNBOUND for unbound workqueues | |
282 | */ | |
706026c2 TH |
283 | #define for_each_wq_cpu(cpu) \ |
284 | for ((cpu) = __next_wq_cpu(-1, cpu_possible_mask, 3); \ | |
6be19588 | 285 | (cpu) < WORK_CPU_END; \ |
706026c2 | 286 | (cpu) = __next_wq_cpu((cpu), cpu_possible_mask, 3)) |
f3421797 | 287 | |
706026c2 TH |
288 | #define for_each_online_wq_cpu(cpu) \ |
289 | for ((cpu) = __next_wq_cpu(-1, cpu_online_mask, 3); \ | |
6be19588 | 290 | (cpu) < WORK_CPU_END; \ |
706026c2 | 291 | (cpu) = __next_wq_cpu((cpu), cpu_online_mask, 3)) |
f3421797 TH |
292 | |
293 | #define for_each_cwq_cpu(cpu, wq) \ | |
706026c2 | 294 | for ((cpu) = __next_cwq_cpu(-1, cpu_possible_mask, (wq)); \ |
6be19588 | 295 | (cpu) < WORK_CPU_END; \ |
706026c2 | 296 | (cpu) = __next_cwq_cpu((cpu), cpu_possible_mask, (wq))) |
f3421797 | 297 | |
dc186ad7 TG |
298 | #ifdef CONFIG_DEBUG_OBJECTS_WORK |
299 | ||
300 | static struct debug_obj_descr work_debug_descr; | |
301 | ||
99777288 SG |
302 | static void *work_debug_hint(void *addr) |
303 | { | |
304 | return ((struct work_struct *) addr)->func; | |
305 | } | |
306 | ||
dc186ad7 TG |
307 | /* |
308 | * fixup_init is called when: | |
309 | * - an active object is initialized | |
310 | */ | |
311 | static int work_fixup_init(void *addr, enum debug_obj_state state) | |
312 | { | |
313 | struct work_struct *work = addr; | |
314 | ||
315 | switch (state) { | |
316 | case ODEBUG_STATE_ACTIVE: | |
317 | cancel_work_sync(work); | |
318 | debug_object_init(work, &work_debug_descr); | |
319 | return 1; | |
320 | default: | |
321 | return 0; | |
322 | } | |
323 | } | |
324 | ||
325 | /* | |
326 | * fixup_activate is called when: | |
327 | * - an active object is activated | |
328 | * - an unknown object is activated (might be a statically initialized object) | |
329 | */ | |
330 | static int work_fixup_activate(void *addr, enum debug_obj_state state) | |
331 | { | |
332 | struct work_struct *work = addr; | |
333 | ||
334 | switch (state) { | |
335 | ||
336 | case ODEBUG_STATE_NOTAVAILABLE: | |
337 | /* | |
338 | * This is not really a fixup. The work struct was | |
339 | * statically initialized. We just make sure that it | |
340 | * is tracked in the object tracker. | |
341 | */ | |
22df02bb | 342 | if (test_bit(WORK_STRUCT_STATIC_BIT, work_data_bits(work))) { |
dc186ad7 TG |
343 | debug_object_init(work, &work_debug_descr); |
344 | debug_object_activate(work, &work_debug_descr); | |
345 | return 0; | |
346 | } | |
347 | WARN_ON_ONCE(1); | |
348 | return 0; | |
349 | ||
350 | case ODEBUG_STATE_ACTIVE: | |
351 | WARN_ON(1); | |
352 | ||
353 | default: | |
354 | return 0; | |
355 | } | |
356 | } | |
357 | ||
358 | /* | |
359 | * fixup_free is called when: | |
360 | * - an active object is freed | |
361 | */ | |
362 | static int work_fixup_free(void *addr, enum debug_obj_state state) | |
363 | { | |
364 | struct work_struct *work = addr; | |
365 | ||
366 | switch (state) { | |
367 | case ODEBUG_STATE_ACTIVE: | |
368 | cancel_work_sync(work); | |
369 | debug_object_free(work, &work_debug_descr); | |
370 | return 1; | |
371 | default: | |
372 | return 0; | |
373 | } | |
374 | } | |
375 | ||
376 | static struct debug_obj_descr work_debug_descr = { | |
377 | .name = "work_struct", | |
99777288 | 378 | .debug_hint = work_debug_hint, |
dc186ad7 TG |
379 | .fixup_init = work_fixup_init, |
380 | .fixup_activate = work_fixup_activate, | |
381 | .fixup_free = work_fixup_free, | |
382 | }; | |
383 | ||
384 | static inline void debug_work_activate(struct work_struct *work) | |
385 | { | |
386 | debug_object_activate(work, &work_debug_descr); | |
387 | } | |
388 | ||
389 | static inline void debug_work_deactivate(struct work_struct *work) | |
390 | { | |
391 | debug_object_deactivate(work, &work_debug_descr); | |
392 | } | |
393 | ||
394 | void __init_work(struct work_struct *work, int onstack) | |
395 | { | |
396 | if (onstack) | |
397 | debug_object_init_on_stack(work, &work_debug_descr); | |
398 | else | |
399 | debug_object_init(work, &work_debug_descr); | |
400 | } | |
401 | EXPORT_SYMBOL_GPL(__init_work); | |
402 | ||
403 | void destroy_work_on_stack(struct work_struct *work) | |
404 | { | |
405 | debug_object_free(work, &work_debug_descr); | |
406 | } | |
407 | EXPORT_SYMBOL_GPL(destroy_work_on_stack); | |
408 | ||
409 | #else | |
410 | static inline void debug_work_activate(struct work_struct *work) { } | |
411 | static inline void debug_work_deactivate(struct work_struct *work) { } | |
412 | #endif | |
413 | ||
95402b38 GS |
414 | /* Serializes the accesses to the list of workqueues. */ |
415 | static DEFINE_SPINLOCK(workqueue_lock); | |
1da177e4 | 416 | static LIST_HEAD(workqueues); |
a0a1a5fd | 417 | static bool workqueue_freezing; /* W: have wqs started freezing? */ |
c34056a3 | 418 | |
e22bee78 | 419 | /* |
a60dc39c TH |
420 | * The CPU standard worker pools. nr_running is the only field which is |
421 | * expected to be used frequently by other cpus via try_to_wake_up(). Put | |
422 | * it in a separate cacheline. | |
e22bee78 | 423 | */ |
a60dc39c TH |
424 | static DEFINE_PER_CPU(struct worker_pool [NR_STD_WORKER_POOLS], |
425 | cpu_std_worker_pools); | |
e6e380ed TH |
426 | static DEFINE_PER_CPU_SHARED_ALIGNED(atomic_t [NR_STD_WORKER_POOLS], |
427 | cpu_std_pool_nr_running); | |
8b03ae3c | 428 | |
f3421797 | 429 | /* |
a60dc39c TH |
430 | * Standard worker pools and nr_running counter for unbound CPU. The pools |
431 | * have POOL_DISASSOCIATED set, and all workers have WORKER_UNBOUND set. | |
f3421797 | 432 | */ |
a60dc39c | 433 | static struct worker_pool unbound_std_worker_pools[NR_STD_WORKER_POOLS]; |
e6e380ed | 434 | static atomic_t unbound_std_pool_nr_running[NR_STD_WORKER_POOLS] = { |
e34cdddb | 435 | [0 ... NR_STD_WORKER_POOLS - 1] = ATOMIC_INIT(0), /* always 0 */ |
4ce62e9e | 436 | }; |
f3421797 | 437 | |
9daf9e67 TH |
438 | /* idr of all pools */ |
439 | static DEFINE_MUTEX(worker_pool_idr_mutex); | |
440 | static DEFINE_IDR(worker_pool_idr); | |
441 | ||
c34056a3 | 442 | static int worker_thread(void *__worker); |
1da177e4 | 443 | |
a60dc39c | 444 | static struct worker_pool *std_worker_pools(int cpu) |
8b03ae3c | 445 | { |
f3421797 | 446 | if (cpu != WORK_CPU_UNBOUND) |
a60dc39c | 447 | return per_cpu(cpu_std_worker_pools, cpu); |
f3421797 | 448 | else |
a60dc39c | 449 | return unbound_std_worker_pools; |
8b03ae3c TH |
450 | } |
451 | ||
4e8f0a60 TH |
452 | static int std_worker_pool_pri(struct worker_pool *pool) |
453 | { | |
a60dc39c | 454 | return pool - std_worker_pools(pool->cpu); |
4e8f0a60 TH |
455 | } |
456 | ||
9daf9e67 TH |
457 | /* allocate ID and assign it to @pool */ |
458 | static int worker_pool_assign_id(struct worker_pool *pool) | |
459 | { | |
460 | int ret; | |
461 | ||
462 | mutex_lock(&worker_pool_idr_mutex); | |
463 | idr_pre_get(&worker_pool_idr, GFP_KERNEL); | |
464 | ret = idr_get_new(&worker_pool_idr, pool, &pool->id); | |
465 | mutex_unlock(&worker_pool_idr_mutex); | |
466 | ||
467 | return ret; | |
468 | } | |
469 | ||
7c3eed5c TH |
470 | /* |
471 | * Lookup worker_pool by id. The idr currently is built during boot and | |
472 | * never modified. Don't worry about locking for now. | |
473 | */ | |
474 | static struct worker_pool *worker_pool_by_id(int pool_id) | |
475 | { | |
476 | return idr_find(&worker_pool_idr, pool_id); | |
477 | } | |
478 | ||
d565ed63 TH |
479 | static struct worker_pool *get_std_worker_pool(int cpu, bool highpri) |
480 | { | |
a60dc39c | 481 | struct worker_pool *pools = std_worker_pools(cpu); |
d565ed63 | 482 | |
a60dc39c | 483 | return &pools[highpri]; |
d565ed63 TH |
484 | } |
485 | ||
63d95a91 | 486 | static atomic_t *get_pool_nr_running(struct worker_pool *pool) |
e22bee78 | 487 | { |
ec22ca5e | 488 | int cpu = pool->cpu; |
e34cdddb | 489 | int idx = std_worker_pool_pri(pool); |
63d95a91 | 490 | |
f3421797 | 491 | if (cpu != WORK_CPU_UNBOUND) |
e6e380ed | 492 | return &per_cpu(cpu_std_pool_nr_running, cpu)[idx]; |
f3421797 | 493 | else |
e6e380ed | 494 | return &unbound_std_pool_nr_running[idx]; |
e22bee78 TH |
495 | } |
496 | ||
1537663f TH |
497 | static struct cpu_workqueue_struct *get_cwq(unsigned int cpu, |
498 | struct workqueue_struct *wq) | |
b1f4ec17 | 499 | { |
f3421797 | 500 | if (!(wq->flags & WQ_UNBOUND)) { |
e06ffa1e | 501 | if (likely(cpu < nr_cpu_ids)) |
f3421797 | 502 | return per_cpu_ptr(wq->cpu_wq.pcpu, cpu); |
f3421797 TH |
503 | } else if (likely(cpu == WORK_CPU_UNBOUND)) |
504 | return wq->cpu_wq.single; | |
505 | return NULL; | |
b1f4ec17 ON |
506 | } |
507 | ||
73f53c4a TH |
508 | static unsigned int work_color_to_flags(int color) |
509 | { | |
510 | return color << WORK_STRUCT_COLOR_SHIFT; | |
511 | } | |
512 | ||
513 | static int get_work_color(struct work_struct *work) | |
514 | { | |
515 | return (*work_data_bits(work) >> WORK_STRUCT_COLOR_SHIFT) & | |
516 | ((1 << WORK_STRUCT_COLOR_BITS) - 1); | |
517 | } | |
518 | ||
519 | static int work_next_color(int color) | |
520 | { | |
521 | return (color + 1) % WORK_NR_COLORS; | |
522 | } | |
1da177e4 | 523 | |
14441960 | 524 | /* |
b5490077 TH |
525 | * While queued, %WORK_STRUCT_CWQ is set and non flag bits of a work's data |
526 | * contain the pointer to the queued cwq. Once execution starts, the flag | |
7c3eed5c | 527 | * is cleared and the high bits contain OFFQ flags and pool ID. |
7a22ad75 | 528 | * |
7c3eed5c TH |
529 | * set_work_cwq(), set_work_pool_and_clear_pending(), mark_work_canceling() |
530 | * and clear_work_data() can be used to set the cwq, pool or clear | |
bbb68dfa TH |
531 | * work->data. These functions should only be called while the work is |
532 | * owned - ie. while the PENDING bit is set. | |
7a22ad75 | 533 | * |
7c3eed5c TH |
534 | * get_work_pool() and get_work_cwq() can be used to obtain the pool or cwq |
535 | * corresponding to a work. Pool is available once the work has been | |
536 | * queued anywhere after initialization until it is sync canceled. cwq is | |
537 | * available only while the work item is queued. | |
7a22ad75 | 538 | * |
bbb68dfa TH |
539 | * %WORK_OFFQ_CANCELING is used to mark a work item which is being |
540 | * canceled. While being canceled, a work item may have its PENDING set | |
541 | * but stay off timer and worklist for arbitrarily long and nobody should | |
542 | * try to steal the PENDING bit. | |
14441960 | 543 | */ |
7a22ad75 TH |
544 | static inline void set_work_data(struct work_struct *work, unsigned long data, |
545 | unsigned long flags) | |
365970a1 | 546 | { |
4594bf15 | 547 | BUG_ON(!work_pending(work)); |
7a22ad75 TH |
548 | atomic_long_set(&work->data, data | flags | work_static(work)); |
549 | } | |
365970a1 | 550 | |
7a22ad75 TH |
551 | static void set_work_cwq(struct work_struct *work, |
552 | struct cpu_workqueue_struct *cwq, | |
553 | unsigned long extra_flags) | |
554 | { | |
555 | set_work_data(work, (unsigned long)cwq, | |
e120153d | 556 | WORK_STRUCT_PENDING | WORK_STRUCT_CWQ | extra_flags); |
365970a1 DH |
557 | } |
558 | ||
4468a00f LJ |
559 | static void set_work_pool_and_keep_pending(struct work_struct *work, |
560 | int pool_id) | |
561 | { | |
562 | set_work_data(work, (unsigned long)pool_id << WORK_OFFQ_POOL_SHIFT, | |
563 | WORK_STRUCT_PENDING); | |
564 | } | |
565 | ||
7c3eed5c TH |
566 | static void set_work_pool_and_clear_pending(struct work_struct *work, |
567 | int pool_id) | |
7a22ad75 | 568 | { |
23657bb1 TH |
569 | /* |
570 | * The following wmb is paired with the implied mb in | |
571 | * test_and_set_bit(PENDING) and ensures all updates to @work made | |
572 | * here are visible to and precede any updates by the next PENDING | |
573 | * owner. | |
574 | */ | |
575 | smp_wmb(); | |
7c3eed5c | 576 | set_work_data(work, (unsigned long)pool_id << WORK_OFFQ_POOL_SHIFT, 0); |
7a22ad75 | 577 | } |
f756d5e2 | 578 | |
7a22ad75 | 579 | static void clear_work_data(struct work_struct *work) |
1da177e4 | 580 | { |
7c3eed5c TH |
581 | smp_wmb(); /* see set_work_pool_and_clear_pending() */ |
582 | set_work_data(work, WORK_STRUCT_NO_POOL, 0); | |
1da177e4 LT |
583 | } |
584 | ||
7a22ad75 | 585 | static struct cpu_workqueue_struct *get_work_cwq(struct work_struct *work) |
b1f4ec17 | 586 | { |
e120153d | 587 | unsigned long data = atomic_long_read(&work->data); |
7a22ad75 | 588 | |
e120153d TH |
589 | if (data & WORK_STRUCT_CWQ) |
590 | return (void *)(data & WORK_STRUCT_WQ_DATA_MASK); | |
591 | else | |
592 | return NULL; | |
4d707b9f ON |
593 | } |
594 | ||
7c3eed5c TH |
595 | /** |
596 | * get_work_pool - return the worker_pool a given work was associated with | |
597 | * @work: the work item of interest | |
598 | * | |
599 | * Return the worker_pool @work was last associated with. %NULL if none. | |
600 | */ | |
601 | static struct worker_pool *get_work_pool(struct work_struct *work) | |
365970a1 | 602 | { |
e120153d | 603 | unsigned long data = atomic_long_read(&work->data); |
7c3eed5c TH |
604 | struct worker_pool *pool; |
605 | int pool_id; | |
7a22ad75 | 606 | |
e120153d TH |
607 | if (data & WORK_STRUCT_CWQ) |
608 | return ((struct cpu_workqueue_struct *) | |
7c3eed5c | 609 | (data & WORK_STRUCT_WQ_DATA_MASK))->pool; |
7a22ad75 | 610 | |
7c3eed5c TH |
611 | pool_id = data >> WORK_OFFQ_POOL_SHIFT; |
612 | if (pool_id == WORK_OFFQ_POOL_NONE) | |
7a22ad75 TH |
613 | return NULL; |
614 | ||
7c3eed5c TH |
615 | pool = worker_pool_by_id(pool_id); |
616 | WARN_ON_ONCE(!pool); | |
617 | return pool; | |
618 | } | |
619 | ||
620 | /** | |
621 | * get_work_pool_id - return the worker pool ID a given work is associated with | |
622 | * @work: the work item of interest | |
623 | * | |
624 | * Return the worker_pool ID @work was last associated with. | |
625 | * %WORK_OFFQ_POOL_NONE if none. | |
626 | */ | |
627 | static int get_work_pool_id(struct work_struct *work) | |
628 | { | |
629 | struct worker_pool *pool = get_work_pool(work); | |
630 | ||
631 | return pool ? pool->id : WORK_OFFQ_POOL_NONE; | |
632 | } | |
633 | ||
bbb68dfa TH |
634 | static void mark_work_canceling(struct work_struct *work) |
635 | { | |
7c3eed5c | 636 | unsigned long pool_id = get_work_pool_id(work); |
bbb68dfa | 637 | |
7c3eed5c TH |
638 | pool_id <<= WORK_OFFQ_POOL_SHIFT; |
639 | set_work_data(work, pool_id | WORK_OFFQ_CANCELING, WORK_STRUCT_PENDING); | |
bbb68dfa TH |
640 | } |
641 | ||
642 | static bool work_is_canceling(struct work_struct *work) | |
643 | { | |
644 | unsigned long data = atomic_long_read(&work->data); | |
645 | ||
646 | return !(data & WORK_STRUCT_CWQ) && (data & WORK_OFFQ_CANCELING); | |
647 | } | |
648 | ||
e22bee78 | 649 | /* |
3270476a TH |
650 | * Policy functions. These define the policies on how the global worker |
651 | * pools are managed. Unless noted otherwise, these functions assume that | |
d565ed63 | 652 | * they're being called with pool->lock held. |
e22bee78 TH |
653 | */ |
654 | ||
63d95a91 | 655 | static bool __need_more_worker(struct worker_pool *pool) |
a848e3b6 | 656 | { |
3270476a | 657 | return !atomic_read(get_pool_nr_running(pool)); |
a848e3b6 ON |
658 | } |
659 | ||
4594bf15 | 660 | /* |
e22bee78 TH |
661 | * Need to wake up a worker? Called from anything but currently |
662 | * running workers. | |
974271c4 TH |
663 | * |
664 | * Note that, because unbound workers never contribute to nr_running, this | |
706026c2 | 665 | * function will always return %true for unbound pools as long as the |
974271c4 | 666 | * worklist isn't empty. |
4594bf15 | 667 | */ |
63d95a91 | 668 | static bool need_more_worker(struct worker_pool *pool) |
365970a1 | 669 | { |
63d95a91 | 670 | return !list_empty(&pool->worklist) && __need_more_worker(pool); |
e22bee78 | 671 | } |
4594bf15 | 672 | |
e22bee78 | 673 | /* Can I start working? Called from busy but !running workers. */ |
63d95a91 | 674 | static bool may_start_working(struct worker_pool *pool) |
e22bee78 | 675 | { |
63d95a91 | 676 | return pool->nr_idle; |
e22bee78 TH |
677 | } |
678 | ||
679 | /* Do I need to keep working? Called from currently running workers. */ | |
63d95a91 | 680 | static bool keep_working(struct worker_pool *pool) |
e22bee78 | 681 | { |
63d95a91 | 682 | atomic_t *nr_running = get_pool_nr_running(pool); |
e22bee78 | 683 | |
3270476a | 684 | return !list_empty(&pool->worklist) && atomic_read(nr_running) <= 1; |
e22bee78 TH |
685 | } |
686 | ||
687 | /* Do we need a new worker? Called from manager. */ | |
63d95a91 | 688 | static bool need_to_create_worker(struct worker_pool *pool) |
e22bee78 | 689 | { |
63d95a91 | 690 | return need_more_worker(pool) && !may_start_working(pool); |
e22bee78 | 691 | } |
365970a1 | 692 | |
e22bee78 | 693 | /* Do I need to be the manager? */ |
63d95a91 | 694 | static bool need_to_manage_workers(struct worker_pool *pool) |
e22bee78 | 695 | { |
63d95a91 | 696 | return need_to_create_worker(pool) || |
11ebea50 | 697 | (pool->flags & POOL_MANAGE_WORKERS); |
e22bee78 TH |
698 | } |
699 | ||
700 | /* Do we have too many workers and should some go away? */ | |
63d95a91 | 701 | static bool too_many_workers(struct worker_pool *pool) |
e22bee78 | 702 | { |
552a37e9 | 703 | bool managing = pool->flags & POOL_MANAGING_WORKERS; |
63d95a91 TH |
704 | int nr_idle = pool->nr_idle + managing; /* manager is considered idle */ |
705 | int nr_busy = pool->nr_workers - nr_idle; | |
e22bee78 | 706 | |
ea1abd61 LJ |
707 | /* |
708 | * nr_idle and idle_list may disagree if idle rebinding is in | |
709 | * progress. Never return %true if idle_list is empty. | |
710 | */ | |
711 | if (list_empty(&pool->idle_list)) | |
712 | return false; | |
713 | ||
e22bee78 | 714 | return nr_idle > 2 && (nr_idle - 2) * MAX_IDLE_WORKERS_RATIO >= nr_busy; |
365970a1 DH |
715 | } |
716 | ||
4d707b9f | 717 | /* |
e22bee78 TH |
718 | * Wake up functions. |
719 | */ | |
720 | ||
7e11629d | 721 | /* Return the first worker. Safe with preemption disabled */ |
63d95a91 | 722 | static struct worker *first_worker(struct worker_pool *pool) |
7e11629d | 723 | { |
63d95a91 | 724 | if (unlikely(list_empty(&pool->idle_list))) |
7e11629d TH |
725 | return NULL; |
726 | ||
63d95a91 | 727 | return list_first_entry(&pool->idle_list, struct worker, entry); |
7e11629d TH |
728 | } |
729 | ||
730 | /** | |
731 | * wake_up_worker - wake up an idle worker | |
63d95a91 | 732 | * @pool: worker pool to wake worker from |
7e11629d | 733 | * |
63d95a91 | 734 | * Wake up the first idle worker of @pool. |
7e11629d TH |
735 | * |
736 | * CONTEXT: | |
d565ed63 | 737 | * spin_lock_irq(pool->lock). |
7e11629d | 738 | */ |
63d95a91 | 739 | static void wake_up_worker(struct worker_pool *pool) |
7e11629d | 740 | { |
63d95a91 | 741 | struct worker *worker = first_worker(pool); |
7e11629d TH |
742 | |
743 | if (likely(worker)) | |
744 | wake_up_process(worker->task); | |
745 | } | |
746 | ||
d302f017 | 747 | /** |
e22bee78 TH |
748 | * wq_worker_waking_up - a worker is waking up |
749 | * @task: task waking up | |
750 | * @cpu: CPU @task is waking up to | |
751 | * | |
752 | * This function is called during try_to_wake_up() when a worker is | |
753 | * being awoken. | |
754 | * | |
755 | * CONTEXT: | |
756 | * spin_lock_irq(rq->lock) | |
757 | */ | |
758 | void wq_worker_waking_up(struct task_struct *task, unsigned int cpu) | |
759 | { | |
760 | struct worker *worker = kthread_data(task); | |
761 | ||
36576000 | 762 | if (!(worker->flags & WORKER_NOT_RUNNING)) { |
ec22ca5e | 763 | WARN_ON_ONCE(worker->pool->cpu != cpu); |
63d95a91 | 764 | atomic_inc(get_pool_nr_running(worker->pool)); |
36576000 | 765 | } |
e22bee78 TH |
766 | } |
767 | ||
768 | /** | |
769 | * wq_worker_sleeping - a worker is going to sleep | |
770 | * @task: task going to sleep | |
771 | * @cpu: CPU in question, must be the current CPU number | |
772 | * | |
773 | * This function is called during schedule() when a busy worker is | |
774 | * going to sleep. Worker on the same cpu can be woken up by | |
775 | * returning pointer to its task. | |
776 | * | |
777 | * CONTEXT: | |
778 | * spin_lock_irq(rq->lock) | |
779 | * | |
780 | * RETURNS: | |
781 | * Worker task on @cpu to wake up, %NULL if none. | |
782 | */ | |
783 | struct task_struct *wq_worker_sleeping(struct task_struct *task, | |
784 | unsigned int cpu) | |
785 | { | |
786 | struct worker *worker = kthread_data(task), *to_wakeup = NULL; | |
111c225a TH |
787 | struct worker_pool *pool; |
788 | atomic_t *nr_running; | |
e22bee78 | 789 | |
111c225a TH |
790 | /* |
791 | * Rescuers, which may not have all the fields set up like normal | |
792 | * workers, also reach here, let's not access anything before | |
793 | * checking NOT_RUNNING. | |
794 | */ | |
2d64672e | 795 | if (worker->flags & WORKER_NOT_RUNNING) |
e22bee78 TH |
796 | return NULL; |
797 | ||
111c225a TH |
798 | pool = worker->pool; |
799 | nr_running = get_pool_nr_running(pool); | |
800 | ||
e22bee78 TH |
801 | /* this can only happen on the local cpu */ |
802 | BUG_ON(cpu != raw_smp_processor_id()); | |
803 | ||
804 | /* | |
805 | * The counterpart of the following dec_and_test, implied mb, | |
806 | * worklist not empty test sequence is in insert_work(). | |
807 | * Please read comment there. | |
808 | * | |
628c78e7 TH |
809 | * NOT_RUNNING is clear. This means that we're bound to and |
810 | * running on the local cpu w/ rq lock held and preemption | |
811 | * disabled, which in turn means that none else could be | |
d565ed63 | 812 | * manipulating idle_list, so dereferencing idle_list without pool |
628c78e7 | 813 | * lock is safe. |
e22bee78 | 814 | */ |
bd7bdd43 | 815 | if (atomic_dec_and_test(nr_running) && !list_empty(&pool->worklist)) |
63d95a91 | 816 | to_wakeup = first_worker(pool); |
e22bee78 TH |
817 | return to_wakeup ? to_wakeup->task : NULL; |
818 | } | |
819 | ||
820 | /** | |
821 | * worker_set_flags - set worker flags and adjust nr_running accordingly | |
cb444766 | 822 | * @worker: self |
d302f017 TH |
823 | * @flags: flags to set |
824 | * @wakeup: wakeup an idle worker if necessary | |
825 | * | |
e22bee78 TH |
826 | * Set @flags in @worker->flags and adjust nr_running accordingly. If |
827 | * nr_running becomes zero and @wakeup is %true, an idle worker is | |
828 | * woken up. | |
d302f017 | 829 | * |
cb444766 | 830 | * CONTEXT: |
d565ed63 | 831 | * spin_lock_irq(pool->lock) |
d302f017 TH |
832 | */ |
833 | static inline void worker_set_flags(struct worker *worker, unsigned int flags, | |
834 | bool wakeup) | |
835 | { | |
bd7bdd43 | 836 | struct worker_pool *pool = worker->pool; |
e22bee78 | 837 | |
cb444766 TH |
838 | WARN_ON_ONCE(worker->task != current); |
839 | ||
e22bee78 TH |
840 | /* |
841 | * If transitioning into NOT_RUNNING, adjust nr_running and | |
842 | * wake up an idle worker as necessary if requested by | |
843 | * @wakeup. | |
844 | */ | |
845 | if ((flags & WORKER_NOT_RUNNING) && | |
846 | !(worker->flags & WORKER_NOT_RUNNING)) { | |
63d95a91 | 847 | atomic_t *nr_running = get_pool_nr_running(pool); |
e22bee78 TH |
848 | |
849 | if (wakeup) { | |
850 | if (atomic_dec_and_test(nr_running) && | |
bd7bdd43 | 851 | !list_empty(&pool->worklist)) |
63d95a91 | 852 | wake_up_worker(pool); |
e22bee78 TH |
853 | } else |
854 | atomic_dec(nr_running); | |
855 | } | |
856 | ||
d302f017 TH |
857 | worker->flags |= flags; |
858 | } | |
859 | ||
860 | /** | |
e22bee78 | 861 | * worker_clr_flags - clear worker flags and adjust nr_running accordingly |
cb444766 | 862 | * @worker: self |
d302f017 TH |
863 | * @flags: flags to clear |
864 | * | |
e22bee78 | 865 | * Clear @flags in @worker->flags and adjust nr_running accordingly. |
d302f017 | 866 | * |
cb444766 | 867 | * CONTEXT: |
d565ed63 | 868 | * spin_lock_irq(pool->lock) |
d302f017 TH |
869 | */ |
870 | static inline void worker_clr_flags(struct worker *worker, unsigned int flags) | |
871 | { | |
63d95a91 | 872 | struct worker_pool *pool = worker->pool; |
e22bee78 TH |
873 | unsigned int oflags = worker->flags; |
874 | ||
cb444766 TH |
875 | WARN_ON_ONCE(worker->task != current); |
876 | ||
d302f017 | 877 | worker->flags &= ~flags; |
e22bee78 | 878 | |
42c025f3 TH |
879 | /* |
880 | * If transitioning out of NOT_RUNNING, increment nr_running. Note | |
881 | * that the nested NOT_RUNNING is not a noop. NOT_RUNNING is mask | |
882 | * of multiple flags, not a single flag. | |
883 | */ | |
e22bee78 TH |
884 | if ((flags & WORKER_NOT_RUNNING) && (oflags & WORKER_NOT_RUNNING)) |
885 | if (!(worker->flags & WORKER_NOT_RUNNING)) | |
63d95a91 | 886 | atomic_inc(get_pool_nr_running(pool)); |
d302f017 TH |
887 | } |
888 | ||
8cca0eea TH |
889 | /** |
890 | * find_worker_executing_work - find worker which is executing a work | |
c9e7cf27 | 891 | * @pool: pool of interest |
8cca0eea TH |
892 | * @work: work to find worker for |
893 | * | |
c9e7cf27 TH |
894 | * Find a worker which is executing @work on @pool by searching |
895 | * @pool->busy_hash which is keyed by the address of @work. For a worker | |
a2c1c57b TH |
896 | * to match, its current execution should match the address of @work and |
897 | * its work function. This is to avoid unwanted dependency between | |
898 | * unrelated work executions through a work item being recycled while still | |
899 | * being executed. | |
900 | * | |
901 | * This is a bit tricky. A work item may be freed once its execution | |
902 | * starts and nothing prevents the freed area from being recycled for | |
903 | * another work item. If the same work item address ends up being reused | |
904 | * before the original execution finishes, workqueue will identify the | |
905 | * recycled work item as currently executing and make it wait until the | |
906 | * current execution finishes, introducing an unwanted dependency. | |
907 | * | |
908 | * This function checks the work item address, work function and workqueue | |
909 | * to avoid false positives. Note that this isn't complete as one may | |
910 | * construct a work function which can introduce dependency onto itself | |
911 | * through a recycled work item. Well, if somebody wants to shoot oneself | |
912 | * in the foot that badly, there's only so much we can do, and if such | |
913 | * deadlock actually occurs, it should be easy to locate the culprit work | |
914 | * function. | |
8cca0eea TH |
915 | * |
916 | * CONTEXT: | |
d565ed63 | 917 | * spin_lock_irq(pool->lock). |
8cca0eea TH |
918 | * |
919 | * RETURNS: | |
920 | * Pointer to worker which is executing @work if found, NULL | |
921 | * otherwise. | |
4d707b9f | 922 | */ |
c9e7cf27 | 923 | static struct worker *find_worker_executing_work(struct worker_pool *pool, |
8cca0eea | 924 | struct work_struct *work) |
4d707b9f | 925 | { |
42f8570f SL |
926 | struct worker *worker; |
927 | struct hlist_node *tmp; | |
928 | ||
c9e7cf27 | 929 | hash_for_each_possible(pool->busy_hash, worker, tmp, hentry, |
a2c1c57b TH |
930 | (unsigned long)work) |
931 | if (worker->current_work == work && | |
932 | worker->current_func == work->func) | |
42f8570f SL |
933 | return worker; |
934 | ||
935 | return NULL; | |
4d707b9f ON |
936 | } |
937 | ||
bf4ede01 TH |
938 | /** |
939 | * move_linked_works - move linked works to a list | |
940 | * @work: start of series of works to be scheduled | |
941 | * @head: target list to append @work to | |
942 | * @nextp: out paramter for nested worklist walking | |
943 | * | |
944 | * Schedule linked works starting from @work to @head. Work series to | |
945 | * be scheduled starts at @work and includes any consecutive work with | |
946 | * WORK_STRUCT_LINKED set in its predecessor. | |
947 | * | |
948 | * If @nextp is not NULL, it's updated to point to the next work of | |
949 | * the last scheduled work. This allows move_linked_works() to be | |
950 | * nested inside outer list_for_each_entry_safe(). | |
951 | * | |
952 | * CONTEXT: | |
d565ed63 | 953 | * spin_lock_irq(pool->lock). |
bf4ede01 TH |
954 | */ |
955 | static void move_linked_works(struct work_struct *work, struct list_head *head, | |
956 | struct work_struct **nextp) | |
957 | { | |
958 | struct work_struct *n; | |
959 | ||
960 | /* | |
961 | * Linked worklist will always end before the end of the list, | |
962 | * use NULL for list head. | |
963 | */ | |
964 | list_for_each_entry_safe_from(work, n, NULL, entry) { | |
965 | list_move_tail(&work->entry, head); | |
966 | if (!(*work_data_bits(work) & WORK_STRUCT_LINKED)) | |
967 | break; | |
968 | } | |
969 | ||
970 | /* | |
971 | * If we're already inside safe list traversal and have moved | |
972 | * multiple works to the scheduled queue, the next position | |
973 | * needs to be updated. | |
974 | */ | |
975 | if (nextp) | |
976 | *nextp = n; | |
977 | } | |
978 | ||
3aa62497 | 979 | static void cwq_activate_delayed_work(struct work_struct *work) |
bf4ede01 | 980 | { |
3aa62497 | 981 | struct cpu_workqueue_struct *cwq = get_work_cwq(work); |
bf4ede01 TH |
982 | |
983 | trace_workqueue_activate_work(work); | |
984 | move_linked_works(work, &cwq->pool->worklist, NULL); | |
985 | __clear_bit(WORK_STRUCT_DELAYED_BIT, work_data_bits(work)); | |
986 | cwq->nr_active++; | |
987 | } | |
988 | ||
3aa62497 LJ |
989 | static void cwq_activate_first_delayed(struct cpu_workqueue_struct *cwq) |
990 | { | |
991 | struct work_struct *work = list_first_entry(&cwq->delayed_works, | |
992 | struct work_struct, entry); | |
993 | ||
994 | cwq_activate_delayed_work(work); | |
995 | } | |
996 | ||
bf4ede01 TH |
997 | /** |
998 | * cwq_dec_nr_in_flight - decrement cwq's nr_in_flight | |
999 | * @cwq: cwq of interest | |
1000 | * @color: color of work which left the queue | |
bf4ede01 TH |
1001 | * |
1002 | * A work either has completed or is removed from pending queue, | |
1003 | * decrement nr_in_flight of its cwq and handle workqueue flushing. | |
1004 | * | |
1005 | * CONTEXT: | |
d565ed63 | 1006 | * spin_lock_irq(pool->lock). |
bf4ede01 | 1007 | */ |
b3f9f405 | 1008 | static void cwq_dec_nr_in_flight(struct cpu_workqueue_struct *cwq, int color) |
bf4ede01 TH |
1009 | { |
1010 | /* ignore uncolored works */ | |
1011 | if (color == WORK_NO_COLOR) | |
1012 | return; | |
1013 | ||
1014 | cwq->nr_in_flight[color]--; | |
1015 | ||
b3f9f405 LJ |
1016 | cwq->nr_active--; |
1017 | if (!list_empty(&cwq->delayed_works)) { | |
1018 | /* one down, submit a delayed one */ | |
1019 | if (cwq->nr_active < cwq->max_active) | |
1020 | cwq_activate_first_delayed(cwq); | |
bf4ede01 TH |
1021 | } |
1022 | ||
1023 | /* is flush in progress and are we at the flushing tip? */ | |
1024 | if (likely(cwq->flush_color != color)) | |
1025 | return; | |
1026 | ||
1027 | /* are there still in-flight works? */ | |
1028 | if (cwq->nr_in_flight[color]) | |
1029 | return; | |
1030 | ||
1031 | /* this cwq is done, clear flush_color */ | |
1032 | cwq->flush_color = -1; | |
1033 | ||
1034 | /* | |
1035 | * If this was the last cwq, wake up the first flusher. It | |
1036 | * will handle the rest. | |
1037 | */ | |
1038 | if (atomic_dec_and_test(&cwq->wq->nr_cwqs_to_flush)) | |
1039 | complete(&cwq->wq->first_flusher->done); | |
1040 | } | |
1041 | ||
36e227d2 | 1042 | /** |
bbb68dfa | 1043 | * try_to_grab_pending - steal work item from worklist and disable irq |
36e227d2 TH |
1044 | * @work: work item to steal |
1045 | * @is_dwork: @work is a delayed_work | |
bbb68dfa | 1046 | * @flags: place to store irq state |
36e227d2 TH |
1047 | * |
1048 | * Try to grab PENDING bit of @work. This function can handle @work in any | |
1049 | * stable state - idle, on timer or on worklist. Return values are | |
1050 | * | |
1051 | * 1 if @work was pending and we successfully stole PENDING | |
1052 | * 0 if @work was idle and we claimed PENDING | |
1053 | * -EAGAIN if PENDING couldn't be grabbed at the moment, safe to busy-retry | |
bbb68dfa TH |
1054 | * -ENOENT if someone else is canceling @work, this state may persist |
1055 | * for arbitrarily long | |
36e227d2 | 1056 | * |
bbb68dfa | 1057 | * On >= 0 return, the caller owns @work's PENDING bit. To avoid getting |
e0aecdd8 TH |
1058 | * interrupted while holding PENDING and @work off queue, irq must be |
1059 | * disabled on entry. This, combined with delayed_work->timer being | |
1060 | * irqsafe, ensures that we return -EAGAIN for finite short period of time. | |
bbb68dfa TH |
1061 | * |
1062 | * On successful return, >= 0, irq is disabled and the caller is | |
1063 | * responsible for releasing it using local_irq_restore(*@flags). | |
1064 | * | |
e0aecdd8 | 1065 | * This function is safe to call from any context including IRQ handler. |
bf4ede01 | 1066 | */ |
bbb68dfa TH |
1067 | static int try_to_grab_pending(struct work_struct *work, bool is_dwork, |
1068 | unsigned long *flags) | |
bf4ede01 | 1069 | { |
d565ed63 | 1070 | struct worker_pool *pool; |
bf4ede01 | 1071 | |
bbb68dfa TH |
1072 | local_irq_save(*flags); |
1073 | ||
36e227d2 TH |
1074 | /* try to steal the timer if it exists */ |
1075 | if (is_dwork) { | |
1076 | struct delayed_work *dwork = to_delayed_work(work); | |
1077 | ||
e0aecdd8 TH |
1078 | /* |
1079 | * dwork->timer is irqsafe. If del_timer() fails, it's | |
1080 | * guaranteed that the timer is not queued anywhere and not | |
1081 | * running on the local CPU. | |
1082 | */ | |
36e227d2 TH |
1083 | if (likely(del_timer(&dwork->timer))) |
1084 | return 1; | |
1085 | } | |
1086 | ||
1087 | /* try to claim PENDING the normal way */ | |
bf4ede01 TH |
1088 | if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) |
1089 | return 0; | |
1090 | ||
1091 | /* | |
1092 | * The queueing is in progress, or it is already queued. Try to | |
1093 | * steal it from ->worklist without clearing WORK_STRUCT_PENDING. | |
1094 | */ | |
d565ed63 TH |
1095 | pool = get_work_pool(work); |
1096 | if (!pool) | |
bbb68dfa | 1097 | goto fail; |
bf4ede01 | 1098 | |
d565ed63 | 1099 | spin_lock(&pool->lock); |
bf4ede01 TH |
1100 | if (!list_empty(&work->entry)) { |
1101 | /* | |
d565ed63 TH |
1102 | * This work is queued, but perhaps we locked the wrong |
1103 | * pool. In that case we must see the new value after | |
1104 | * rmb(), see insert_work()->wmb(). | |
bf4ede01 TH |
1105 | */ |
1106 | smp_rmb(); | |
d565ed63 | 1107 | if (pool == get_work_pool(work)) { |
bf4ede01 | 1108 | debug_work_deactivate(work); |
3aa62497 LJ |
1109 | |
1110 | /* | |
1111 | * A delayed work item cannot be grabbed directly | |
1112 | * because it might have linked NO_COLOR work items | |
1113 | * which, if left on the delayed_list, will confuse | |
1114 | * cwq->nr_active management later on and cause | |
1115 | * stall. Make sure the work item is activated | |
1116 | * before grabbing. | |
1117 | */ | |
1118 | if (*work_data_bits(work) & WORK_STRUCT_DELAYED) | |
1119 | cwq_activate_delayed_work(work); | |
1120 | ||
bf4ede01 TH |
1121 | list_del_init(&work->entry); |
1122 | cwq_dec_nr_in_flight(get_work_cwq(work), | |
b3f9f405 | 1123 | get_work_color(work)); |
36e227d2 | 1124 | |
4468a00f LJ |
1125 | /* work->data points to cwq iff queued, point to pool */ |
1126 | set_work_pool_and_keep_pending(work, pool->id); | |
1127 | ||
d565ed63 | 1128 | spin_unlock(&pool->lock); |
36e227d2 | 1129 | return 1; |
bf4ede01 TH |
1130 | } |
1131 | } | |
d565ed63 | 1132 | spin_unlock(&pool->lock); |
bbb68dfa TH |
1133 | fail: |
1134 | local_irq_restore(*flags); | |
1135 | if (work_is_canceling(work)) | |
1136 | return -ENOENT; | |
1137 | cpu_relax(); | |
36e227d2 | 1138 | return -EAGAIN; |
bf4ede01 TH |
1139 | } |
1140 | ||
4690c4ab | 1141 | /** |
706026c2 | 1142 | * insert_work - insert a work into a pool |
4690c4ab TH |
1143 | * @cwq: cwq @work belongs to |
1144 | * @work: work to insert | |
1145 | * @head: insertion point | |
1146 | * @extra_flags: extra WORK_STRUCT_* flags to set | |
1147 | * | |
706026c2 TH |
1148 | * Insert @work which belongs to @cwq after @head. @extra_flags is or'd to |
1149 | * work_struct flags. | |
4690c4ab TH |
1150 | * |
1151 | * CONTEXT: | |
d565ed63 | 1152 | * spin_lock_irq(pool->lock). |
4690c4ab | 1153 | */ |
b89deed3 | 1154 | static void insert_work(struct cpu_workqueue_struct *cwq, |
4690c4ab TH |
1155 | struct work_struct *work, struct list_head *head, |
1156 | unsigned int extra_flags) | |
b89deed3 | 1157 | { |
63d95a91 | 1158 | struct worker_pool *pool = cwq->pool; |
e22bee78 | 1159 | |
4690c4ab | 1160 | /* we own @work, set data and link */ |
7a22ad75 | 1161 | set_work_cwq(work, cwq, extra_flags); |
e1d8aa9f | 1162 | |
6e84d644 ON |
1163 | /* |
1164 | * Ensure that we get the right work->data if we see the | |
1165 | * result of list_add() below, see try_to_grab_pending(). | |
1166 | */ | |
1167 | smp_wmb(); | |
4690c4ab | 1168 | |
1a4d9b0a | 1169 | list_add_tail(&work->entry, head); |
e22bee78 TH |
1170 | |
1171 | /* | |
1172 | * Ensure either worker_sched_deactivated() sees the above | |
1173 | * list_add_tail() or we see zero nr_running to avoid workers | |
1174 | * lying around lazily while there are works to be processed. | |
1175 | */ | |
1176 | smp_mb(); | |
1177 | ||
63d95a91 TH |
1178 | if (__need_more_worker(pool)) |
1179 | wake_up_worker(pool); | |
b89deed3 ON |
1180 | } |
1181 | ||
c8efcc25 TH |
1182 | /* |
1183 | * Test whether @work is being queued from another work executing on the | |
1184 | * same workqueue. This is rather expensive and should only be used from | |
1185 | * cold paths. | |
1186 | */ | |
1187 | static bool is_chained_work(struct workqueue_struct *wq) | |
1188 | { | |
1189 | unsigned long flags; | |
1190 | unsigned int cpu; | |
1191 | ||
706026c2 | 1192 | for_each_wq_cpu(cpu) { |
c9e7cf27 TH |
1193 | struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); |
1194 | struct worker_pool *pool = cwq->pool; | |
c8efcc25 TH |
1195 | struct worker *worker; |
1196 | struct hlist_node *pos; | |
1197 | int i; | |
1198 | ||
d565ed63 | 1199 | spin_lock_irqsave(&pool->lock, flags); |
c9e7cf27 | 1200 | for_each_busy_worker(worker, i, pos, pool) { |
c8efcc25 TH |
1201 | if (worker->task != current) |
1202 | continue; | |
d565ed63 | 1203 | spin_unlock_irqrestore(&pool->lock, flags); |
c8efcc25 TH |
1204 | /* |
1205 | * I'm @worker, no locking necessary. See if @work | |
1206 | * is headed to the same workqueue. | |
1207 | */ | |
1208 | return worker->current_cwq->wq == wq; | |
1209 | } | |
d565ed63 | 1210 | spin_unlock_irqrestore(&pool->lock, flags); |
c8efcc25 TH |
1211 | } |
1212 | return false; | |
1213 | } | |
1214 | ||
4690c4ab | 1215 | static void __queue_work(unsigned int cpu, struct workqueue_struct *wq, |
1da177e4 LT |
1216 | struct work_struct *work) |
1217 | { | |
d565ed63 TH |
1218 | bool highpri = wq->flags & WQ_HIGHPRI; |
1219 | struct worker_pool *pool; | |
502ca9d8 | 1220 | struct cpu_workqueue_struct *cwq; |
1e19ffc6 | 1221 | struct list_head *worklist; |
8a2e8e5d | 1222 | unsigned int work_flags; |
b75cac93 | 1223 | unsigned int req_cpu = cpu; |
8930caba TH |
1224 | |
1225 | /* | |
1226 | * While a work item is PENDING && off queue, a task trying to | |
1227 | * steal the PENDING will busy-loop waiting for it to either get | |
1228 | * queued or lose PENDING. Grabbing PENDING and queueing should | |
1229 | * happen with IRQ disabled. | |
1230 | */ | |
1231 | WARN_ON_ONCE(!irqs_disabled()); | |
1da177e4 | 1232 | |
dc186ad7 | 1233 | debug_work_activate(work); |
1e19ffc6 | 1234 | |
c8efcc25 | 1235 | /* if dying, only works from the same workqueue are allowed */ |
9c5a2ba7 | 1236 | if (unlikely(wq->flags & WQ_DRAINING) && |
c8efcc25 | 1237 | WARN_ON_ONCE(!is_chained_work(wq))) |
e41e704b TH |
1238 | return; |
1239 | ||
d565ed63 | 1240 | /* determine pool to use */ |
c7fc77f7 | 1241 | if (!(wq->flags & WQ_UNBOUND)) { |
c9e7cf27 | 1242 | struct worker_pool *last_pool; |
18aa9eff | 1243 | |
57469821 | 1244 | if (cpu == WORK_CPU_UNBOUND) |
c7fc77f7 TH |
1245 | cpu = raw_smp_processor_id(); |
1246 | ||
18aa9eff | 1247 | /* |
dbf2576e TH |
1248 | * It's multi cpu. If @work was previously on a different |
1249 | * cpu, it might still be running there, in which case the | |
1250 | * work needs to be queued on that cpu to guarantee | |
1251 | * non-reentrancy. | |
18aa9eff | 1252 | */ |
d565ed63 | 1253 | pool = get_std_worker_pool(cpu, highpri); |
c9e7cf27 | 1254 | last_pool = get_work_pool(work); |
dbf2576e | 1255 | |
d565ed63 | 1256 | if (last_pool && last_pool != pool) { |
18aa9eff TH |
1257 | struct worker *worker; |
1258 | ||
d565ed63 | 1259 | spin_lock(&last_pool->lock); |
18aa9eff | 1260 | |
c9e7cf27 | 1261 | worker = find_worker_executing_work(last_pool, work); |
18aa9eff TH |
1262 | |
1263 | if (worker && worker->current_cwq->wq == wq) | |
d565ed63 | 1264 | pool = last_pool; |
18aa9eff TH |
1265 | else { |
1266 | /* meh... not running there, queue here */ | |
d565ed63 TH |
1267 | spin_unlock(&last_pool->lock); |
1268 | spin_lock(&pool->lock); | |
18aa9eff | 1269 | } |
8930caba | 1270 | } else { |
d565ed63 | 1271 | spin_lock(&pool->lock); |
8930caba | 1272 | } |
f3421797 | 1273 | } else { |
d565ed63 TH |
1274 | pool = get_std_worker_pool(WORK_CPU_UNBOUND, highpri); |
1275 | spin_lock(&pool->lock); | |
502ca9d8 TH |
1276 | } |
1277 | ||
d565ed63 TH |
1278 | /* pool determined, get cwq and queue */ |
1279 | cwq = get_cwq(pool->cpu, wq); | |
b75cac93 | 1280 | trace_workqueue_queue_work(req_cpu, cwq, work); |
502ca9d8 | 1281 | |
f5b2552b | 1282 | if (WARN_ON(!list_empty(&work->entry))) { |
d565ed63 | 1283 | spin_unlock(&pool->lock); |
f5b2552b DC |
1284 | return; |
1285 | } | |
1e19ffc6 | 1286 | |
73f53c4a | 1287 | cwq->nr_in_flight[cwq->work_color]++; |
8a2e8e5d | 1288 | work_flags = work_color_to_flags(cwq->work_color); |
1e19ffc6 TH |
1289 | |
1290 | if (likely(cwq->nr_active < cwq->max_active)) { | |
cdadf009 | 1291 | trace_workqueue_activate_work(work); |
1e19ffc6 | 1292 | cwq->nr_active++; |
3270476a | 1293 | worklist = &cwq->pool->worklist; |
8a2e8e5d TH |
1294 | } else { |
1295 | work_flags |= WORK_STRUCT_DELAYED; | |
1e19ffc6 | 1296 | worklist = &cwq->delayed_works; |
8a2e8e5d | 1297 | } |
1e19ffc6 | 1298 | |
8a2e8e5d | 1299 | insert_work(cwq, work, worklist, work_flags); |
1e19ffc6 | 1300 | |
d565ed63 | 1301 | spin_unlock(&pool->lock); |
1da177e4 LT |
1302 | } |
1303 | ||
0fcb78c2 | 1304 | /** |
c1a220e7 ZR |
1305 | * queue_work_on - queue work on specific cpu |
1306 | * @cpu: CPU number to execute work on | |
0fcb78c2 REB |
1307 | * @wq: workqueue to use |
1308 | * @work: work to queue | |
1309 | * | |
d4283e93 | 1310 | * Returns %false if @work was already on a queue, %true otherwise. |
1da177e4 | 1311 | * |
c1a220e7 ZR |
1312 | * We queue the work to a specific CPU, the caller must ensure it |
1313 | * can't go away. | |
1da177e4 | 1314 | */ |
d4283e93 TH |
1315 | bool queue_work_on(int cpu, struct workqueue_struct *wq, |
1316 | struct work_struct *work) | |
1da177e4 | 1317 | { |
d4283e93 | 1318 | bool ret = false; |
8930caba | 1319 | unsigned long flags; |
ef1ca236 | 1320 | |
8930caba | 1321 | local_irq_save(flags); |
c1a220e7 | 1322 | |
22df02bb | 1323 | if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) { |
4690c4ab | 1324 | __queue_work(cpu, wq, work); |
d4283e93 | 1325 | ret = true; |
c1a220e7 | 1326 | } |
ef1ca236 | 1327 | |
8930caba | 1328 | local_irq_restore(flags); |
1da177e4 LT |
1329 | return ret; |
1330 | } | |
c1a220e7 | 1331 | EXPORT_SYMBOL_GPL(queue_work_on); |
1da177e4 | 1332 | |
c1a220e7 | 1333 | /** |
0a13c00e | 1334 | * queue_work - queue work on a workqueue |
c1a220e7 ZR |
1335 | * @wq: workqueue to use |
1336 | * @work: work to queue | |
1337 | * | |
d4283e93 | 1338 | * Returns %false if @work was already on a queue, %true otherwise. |
c1a220e7 | 1339 | * |
0a13c00e TH |
1340 | * We queue the work to the CPU on which it was submitted, but if the CPU dies |
1341 | * it can be processed by another CPU. | |
c1a220e7 | 1342 | */ |
d4283e93 | 1343 | bool queue_work(struct workqueue_struct *wq, struct work_struct *work) |
c1a220e7 | 1344 | { |
57469821 | 1345 | return queue_work_on(WORK_CPU_UNBOUND, wq, work); |
c1a220e7 | 1346 | } |
0a13c00e | 1347 | EXPORT_SYMBOL_GPL(queue_work); |
c1a220e7 | 1348 | |
d8e794df | 1349 | void delayed_work_timer_fn(unsigned long __data) |
1da177e4 | 1350 | { |
52bad64d | 1351 | struct delayed_work *dwork = (struct delayed_work *)__data; |
1da177e4 | 1352 | |
e0aecdd8 | 1353 | /* should have been called from irqsafe timer with irq already off */ |
60c057bc | 1354 | __queue_work(dwork->cpu, dwork->wq, &dwork->work); |
1da177e4 | 1355 | } |
d8e794df | 1356 | EXPORT_SYMBOL_GPL(delayed_work_timer_fn); |
1da177e4 | 1357 | |
7beb2edf TH |
1358 | static void __queue_delayed_work(int cpu, struct workqueue_struct *wq, |
1359 | struct delayed_work *dwork, unsigned long delay) | |
1da177e4 | 1360 | { |
7beb2edf TH |
1361 | struct timer_list *timer = &dwork->timer; |
1362 | struct work_struct *work = &dwork->work; | |
7beb2edf TH |
1363 | |
1364 | WARN_ON_ONCE(timer->function != delayed_work_timer_fn || | |
1365 | timer->data != (unsigned long)dwork); | |
fc4b514f TH |
1366 | WARN_ON_ONCE(timer_pending(timer)); |
1367 | WARN_ON_ONCE(!list_empty(&work->entry)); | |
7beb2edf | 1368 | |
8852aac2 TH |
1369 | /* |
1370 | * If @delay is 0, queue @dwork->work immediately. This is for | |
1371 | * both optimization and correctness. The earliest @timer can | |
1372 | * expire is on the closest next tick and delayed_work users depend | |
1373 | * on that there's no such delay when @delay is 0. | |
1374 | */ | |
1375 | if (!delay) { | |
1376 | __queue_work(cpu, wq, &dwork->work); | |
1377 | return; | |
1378 | } | |
1379 | ||
7beb2edf | 1380 | timer_stats_timer_set_start_info(&dwork->timer); |
1da177e4 | 1381 | |
60c057bc | 1382 | dwork->wq = wq; |
1265057f | 1383 | dwork->cpu = cpu; |
7beb2edf TH |
1384 | timer->expires = jiffies + delay; |
1385 | ||
1386 | if (unlikely(cpu != WORK_CPU_UNBOUND)) | |
1387 | add_timer_on(timer, cpu); | |
1388 | else | |
1389 | add_timer(timer); | |
1da177e4 LT |
1390 | } |
1391 | ||
0fcb78c2 REB |
1392 | /** |
1393 | * queue_delayed_work_on - queue work on specific CPU after delay | |
1394 | * @cpu: CPU number to execute work on | |
1395 | * @wq: workqueue to use | |
af9997e4 | 1396 | * @dwork: work to queue |
0fcb78c2 REB |
1397 | * @delay: number of jiffies to wait before queueing |
1398 | * | |
715f1300 TH |
1399 | * Returns %false if @work was already on a queue, %true otherwise. If |
1400 | * @delay is zero and @dwork is idle, it will be scheduled for immediate | |
1401 | * execution. | |
0fcb78c2 | 1402 | */ |
d4283e93 TH |
1403 | bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq, |
1404 | struct delayed_work *dwork, unsigned long delay) | |
7a6bc1cd | 1405 | { |
52bad64d | 1406 | struct work_struct *work = &dwork->work; |
d4283e93 | 1407 | bool ret = false; |
8930caba | 1408 | unsigned long flags; |
7a6bc1cd | 1409 | |
8930caba TH |
1410 | /* read the comment in __queue_work() */ |
1411 | local_irq_save(flags); | |
7a6bc1cd | 1412 | |
22df02bb | 1413 | if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) { |
7beb2edf | 1414 | __queue_delayed_work(cpu, wq, dwork, delay); |
d4283e93 | 1415 | ret = true; |
7a6bc1cd | 1416 | } |
8a3e77cc | 1417 | |
8930caba | 1418 | local_irq_restore(flags); |
7a6bc1cd VP |
1419 | return ret; |
1420 | } | |
ae90dd5d | 1421 | EXPORT_SYMBOL_GPL(queue_delayed_work_on); |
c7fc77f7 | 1422 | |
0a13c00e TH |
1423 | /** |
1424 | * queue_delayed_work - queue work on a workqueue after delay | |
1425 | * @wq: workqueue to use | |
1426 | * @dwork: delayable work to queue | |
1427 | * @delay: number of jiffies to wait before queueing | |
1428 | * | |
715f1300 | 1429 | * Equivalent to queue_delayed_work_on() but tries to use the local CPU. |
0a13c00e | 1430 | */ |
d4283e93 | 1431 | bool queue_delayed_work(struct workqueue_struct *wq, |
0a13c00e TH |
1432 | struct delayed_work *dwork, unsigned long delay) |
1433 | { | |
57469821 | 1434 | return queue_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay); |
0a13c00e TH |
1435 | } |
1436 | EXPORT_SYMBOL_GPL(queue_delayed_work); | |
c7fc77f7 | 1437 | |
8376fe22 TH |
1438 | /** |
1439 | * mod_delayed_work_on - modify delay of or queue a delayed work on specific CPU | |
1440 | * @cpu: CPU number to execute work on | |
1441 | * @wq: workqueue to use | |
1442 | * @dwork: work to queue | |
1443 | * @delay: number of jiffies to wait before queueing | |
1444 | * | |
1445 | * If @dwork is idle, equivalent to queue_delayed_work_on(); otherwise, | |
1446 | * modify @dwork's timer so that it expires after @delay. If @delay is | |
1447 | * zero, @work is guaranteed to be scheduled immediately regardless of its | |
1448 | * current state. | |
1449 | * | |
1450 | * Returns %false if @dwork was idle and queued, %true if @dwork was | |
1451 | * pending and its timer was modified. | |
1452 | * | |
e0aecdd8 | 1453 | * This function is safe to call from any context including IRQ handler. |
8376fe22 TH |
1454 | * See try_to_grab_pending() for details. |
1455 | */ | |
1456 | bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq, | |
1457 | struct delayed_work *dwork, unsigned long delay) | |
1458 | { | |
1459 | unsigned long flags; | |
1460 | int ret; | |
c7fc77f7 | 1461 | |
8376fe22 TH |
1462 | do { |
1463 | ret = try_to_grab_pending(&dwork->work, true, &flags); | |
1464 | } while (unlikely(ret == -EAGAIN)); | |
63bc0362 | 1465 | |
8376fe22 TH |
1466 | if (likely(ret >= 0)) { |
1467 | __queue_delayed_work(cpu, wq, dwork, delay); | |
1468 | local_irq_restore(flags); | |
7a6bc1cd | 1469 | } |
8376fe22 TH |
1470 | |
1471 | /* -ENOENT from try_to_grab_pending() becomes %true */ | |
7a6bc1cd VP |
1472 | return ret; |
1473 | } | |
8376fe22 TH |
1474 | EXPORT_SYMBOL_GPL(mod_delayed_work_on); |
1475 | ||
1476 | /** | |
1477 | * mod_delayed_work - modify delay of or queue a delayed work | |
1478 | * @wq: workqueue to use | |
1479 | * @dwork: work to queue | |
1480 | * @delay: number of jiffies to wait before queueing | |
1481 | * | |
1482 | * mod_delayed_work_on() on local CPU. | |
1483 | */ | |
1484 | bool mod_delayed_work(struct workqueue_struct *wq, struct delayed_work *dwork, | |
1485 | unsigned long delay) | |
1486 | { | |
1487 | return mod_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay); | |
1488 | } | |
1489 | EXPORT_SYMBOL_GPL(mod_delayed_work); | |
1da177e4 | 1490 | |
c8e55f36 TH |
1491 | /** |
1492 | * worker_enter_idle - enter idle state | |
1493 | * @worker: worker which is entering idle state | |
1494 | * | |
1495 | * @worker is entering idle state. Update stats and idle timer if | |
1496 | * necessary. | |
1497 | * | |
1498 | * LOCKING: | |
d565ed63 | 1499 | * spin_lock_irq(pool->lock). |
c8e55f36 TH |
1500 | */ |
1501 | static void worker_enter_idle(struct worker *worker) | |
1da177e4 | 1502 | { |
bd7bdd43 | 1503 | struct worker_pool *pool = worker->pool; |
c8e55f36 TH |
1504 | |
1505 | BUG_ON(worker->flags & WORKER_IDLE); | |
1506 | BUG_ON(!list_empty(&worker->entry) && | |
1507 | (worker->hentry.next || worker->hentry.pprev)); | |
1508 | ||
cb444766 TH |
1509 | /* can't use worker_set_flags(), also called from start_worker() */ |
1510 | worker->flags |= WORKER_IDLE; | |
bd7bdd43 | 1511 | pool->nr_idle++; |
e22bee78 | 1512 | worker->last_active = jiffies; |
c8e55f36 TH |
1513 | |
1514 | /* idle_list is LIFO */ | |
bd7bdd43 | 1515 | list_add(&worker->entry, &pool->idle_list); |
db7bccf4 | 1516 | |
628c78e7 TH |
1517 | if (too_many_workers(pool) && !timer_pending(&pool->idle_timer)) |
1518 | mod_timer(&pool->idle_timer, jiffies + IDLE_WORKER_TIMEOUT); | |
cb444766 | 1519 | |
544ecf31 | 1520 | /* |
706026c2 | 1521 | * Sanity check nr_running. Because wq_unbind_fn() releases |
d565ed63 | 1522 | * pool->lock between setting %WORKER_UNBOUND and zapping |
628c78e7 TH |
1523 | * nr_running, the warning may trigger spuriously. Check iff |
1524 | * unbind is not in progress. | |
544ecf31 | 1525 | */ |
24647570 | 1526 | WARN_ON_ONCE(!(pool->flags & POOL_DISASSOCIATED) && |
bd7bdd43 | 1527 | pool->nr_workers == pool->nr_idle && |
63d95a91 | 1528 | atomic_read(get_pool_nr_running(pool))); |
c8e55f36 TH |
1529 | } |
1530 | ||
1531 | /** | |
1532 | * worker_leave_idle - leave idle state | |
1533 | * @worker: worker which is leaving idle state | |
1534 | * | |
1535 | * @worker is leaving idle state. Update stats. | |
1536 | * | |
1537 | * LOCKING: | |
d565ed63 | 1538 | * spin_lock_irq(pool->lock). |
c8e55f36 TH |
1539 | */ |
1540 | static void worker_leave_idle(struct worker *worker) | |
1541 | { | |
bd7bdd43 | 1542 | struct worker_pool *pool = worker->pool; |
c8e55f36 TH |
1543 | |
1544 | BUG_ON(!(worker->flags & WORKER_IDLE)); | |
d302f017 | 1545 | worker_clr_flags(worker, WORKER_IDLE); |
bd7bdd43 | 1546 | pool->nr_idle--; |
c8e55f36 TH |
1547 | list_del_init(&worker->entry); |
1548 | } | |
1549 | ||
e22bee78 | 1550 | /** |
706026c2 | 1551 | * worker_maybe_bind_and_lock - bind worker to its cpu if possible and lock pool |
e22bee78 TH |
1552 | * @worker: self |
1553 | * | |
1554 | * Works which are scheduled while the cpu is online must at least be | |
1555 | * scheduled to a worker which is bound to the cpu so that if they are | |
1556 | * flushed from cpu callbacks while cpu is going down, they are | |
1557 | * guaranteed to execute on the cpu. | |
1558 | * | |
1559 | * This function is to be used by rogue workers and rescuers to bind | |
1560 | * themselves to the target cpu and may race with cpu going down or | |
1561 | * coming online. kthread_bind() can't be used because it may put the | |
1562 | * worker to already dead cpu and set_cpus_allowed_ptr() can't be used | |
706026c2 | 1563 | * verbatim as it's best effort and blocking and pool may be |
e22bee78 TH |
1564 | * [dis]associated in the meantime. |
1565 | * | |
706026c2 | 1566 | * This function tries set_cpus_allowed() and locks pool and verifies the |
24647570 | 1567 | * binding against %POOL_DISASSOCIATED which is set during |
f2d5a0ee TH |
1568 | * %CPU_DOWN_PREPARE and cleared during %CPU_ONLINE, so if the worker |
1569 | * enters idle state or fetches works without dropping lock, it can | |
1570 | * guarantee the scheduling requirement described in the first paragraph. | |
e22bee78 TH |
1571 | * |
1572 | * CONTEXT: | |
d565ed63 | 1573 | * Might sleep. Called without any lock but returns with pool->lock |
e22bee78 TH |
1574 | * held. |
1575 | * | |
1576 | * RETURNS: | |
706026c2 | 1577 | * %true if the associated pool is online (@worker is successfully |
e22bee78 TH |
1578 | * bound), %false if offline. |
1579 | */ | |
1580 | static bool worker_maybe_bind_and_lock(struct worker *worker) | |
d565ed63 | 1581 | __acquires(&pool->lock) |
e22bee78 | 1582 | { |
24647570 | 1583 | struct worker_pool *pool = worker->pool; |
e22bee78 TH |
1584 | struct task_struct *task = worker->task; |
1585 | ||
1586 | while (true) { | |
4e6045f1 | 1587 | /* |
e22bee78 TH |
1588 | * The following call may fail, succeed or succeed |
1589 | * without actually migrating the task to the cpu if | |
1590 | * it races with cpu hotunplug operation. Verify | |
24647570 | 1591 | * against POOL_DISASSOCIATED. |
4e6045f1 | 1592 | */ |
24647570 | 1593 | if (!(pool->flags & POOL_DISASSOCIATED)) |
ec22ca5e | 1594 | set_cpus_allowed_ptr(task, get_cpu_mask(pool->cpu)); |
e22bee78 | 1595 | |
d565ed63 | 1596 | spin_lock_irq(&pool->lock); |
24647570 | 1597 | if (pool->flags & POOL_DISASSOCIATED) |
e22bee78 | 1598 | return false; |
ec22ca5e | 1599 | if (task_cpu(task) == pool->cpu && |
e22bee78 | 1600 | cpumask_equal(¤t->cpus_allowed, |
ec22ca5e | 1601 | get_cpu_mask(pool->cpu))) |
e22bee78 | 1602 | return true; |
d565ed63 | 1603 | spin_unlock_irq(&pool->lock); |
e22bee78 | 1604 | |
5035b20f TH |
1605 | /* |
1606 | * We've raced with CPU hot[un]plug. Give it a breather | |
1607 | * and retry migration. cond_resched() is required here; | |
1608 | * otherwise, we might deadlock against cpu_stop trying to | |
1609 | * bring down the CPU on non-preemptive kernel. | |
1610 | */ | |
e22bee78 | 1611 | cpu_relax(); |
5035b20f | 1612 | cond_resched(); |
e22bee78 TH |
1613 | } |
1614 | } | |
1615 | ||
25511a47 | 1616 | /* |
ea1abd61 | 1617 | * Rebind an idle @worker to its CPU. worker_thread() will test |
5f7dabfd | 1618 | * list_empty(@worker->entry) before leaving idle and call this function. |
25511a47 TH |
1619 | */ |
1620 | static void idle_worker_rebind(struct worker *worker) | |
1621 | { | |
5f7dabfd LJ |
1622 | /* CPU may go down again inbetween, clear UNBOUND only on success */ |
1623 | if (worker_maybe_bind_and_lock(worker)) | |
1624 | worker_clr_flags(worker, WORKER_UNBOUND); | |
25511a47 | 1625 | |
ea1abd61 LJ |
1626 | /* rebind complete, become available again */ |
1627 | list_add(&worker->entry, &worker->pool->idle_list); | |
d565ed63 | 1628 | spin_unlock_irq(&worker->pool->lock); |
25511a47 TH |
1629 | } |
1630 | ||
e22bee78 | 1631 | /* |
25511a47 | 1632 | * Function for @worker->rebind.work used to rebind unbound busy workers to |
403c821d TH |
1633 | * the associated cpu which is coming back online. This is scheduled by |
1634 | * cpu up but can race with other cpu hotplug operations and may be | |
1635 | * executed twice without intervening cpu down. | |
e22bee78 | 1636 | */ |
25511a47 | 1637 | static void busy_worker_rebind_fn(struct work_struct *work) |
e22bee78 TH |
1638 | { |
1639 | struct worker *worker = container_of(work, struct worker, rebind_work); | |
e22bee78 | 1640 | |
eab6d828 LJ |
1641 | if (worker_maybe_bind_and_lock(worker)) |
1642 | worker_clr_flags(worker, WORKER_UNBOUND); | |
e22bee78 | 1643 | |
d565ed63 | 1644 | spin_unlock_irq(&worker->pool->lock); |
e22bee78 TH |
1645 | } |
1646 | ||
25511a47 | 1647 | /** |
94cf58bb TH |
1648 | * rebind_workers - rebind all workers of a pool to the associated CPU |
1649 | * @pool: pool of interest | |
25511a47 | 1650 | * |
94cf58bb | 1651 | * @pool->cpu is coming online. Rebind all workers to the CPU. Rebinding |
25511a47 TH |
1652 | * is different for idle and busy ones. |
1653 | * | |
ea1abd61 LJ |
1654 | * Idle ones will be removed from the idle_list and woken up. They will |
1655 | * add themselves back after completing rebind. This ensures that the | |
1656 | * idle_list doesn't contain any unbound workers when re-bound busy workers | |
1657 | * try to perform local wake-ups for concurrency management. | |
25511a47 | 1658 | * |
ea1abd61 LJ |
1659 | * Busy workers can rebind after they finish their current work items. |
1660 | * Queueing the rebind work item at the head of the scheduled list is | |
1661 | * enough. Note that nr_running will be properly bumped as busy workers | |
1662 | * rebind. | |
25511a47 | 1663 | * |
ea1abd61 LJ |
1664 | * On return, all non-manager workers are scheduled for rebind - see |
1665 | * manage_workers() for the manager special case. Any idle worker | |
1666 | * including the manager will not appear on @idle_list until rebind is | |
1667 | * complete, making local wake-ups safe. | |
25511a47 | 1668 | */ |
94cf58bb | 1669 | static void rebind_workers(struct worker_pool *pool) |
25511a47 | 1670 | { |
ea1abd61 | 1671 | struct worker *worker, *n; |
25511a47 TH |
1672 | struct hlist_node *pos; |
1673 | int i; | |
1674 | ||
94cf58bb TH |
1675 | lockdep_assert_held(&pool->assoc_mutex); |
1676 | lockdep_assert_held(&pool->lock); | |
25511a47 | 1677 | |
5f7dabfd | 1678 | /* dequeue and kick idle ones */ |
94cf58bb TH |
1679 | list_for_each_entry_safe(worker, n, &pool->idle_list, entry) { |
1680 | /* | |
1681 | * idle workers should be off @pool->idle_list until rebind | |
1682 | * is complete to avoid receiving premature local wake-ups. | |
1683 | */ | |
1684 | list_del_init(&worker->entry); | |
25511a47 | 1685 | |
94cf58bb TH |
1686 | /* |
1687 | * worker_thread() will see the above dequeuing and call | |
1688 | * idle_worker_rebind(). | |
1689 | */ | |
1690 | wake_up_process(worker->task); | |
1691 | } | |
25511a47 | 1692 | |
94cf58bb TH |
1693 | /* rebind busy workers */ |
1694 | for_each_busy_worker(worker, i, pos, pool) { | |
1695 | struct work_struct *rebind_work = &worker->rebind_work; | |
1696 | struct workqueue_struct *wq; | |
25511a47 | 1697 | |
94cf58bb TH |
1698 | if (test_and_set_bit(WORK_STRUCT_PENDING_BIT, |
1699 | work_data_bits(rebind_work))) | |
1700 | continue; | |
25511a47 | 1701 | |
94cf58bb | 1702 | debug_work_activate(rebind_work); |
90beca5d | 1703 | |
94cf58bb TH |
1704 | /* |
1705 | * wq doesn't really matter but let's keep @worker->pool | |
1706 | * and @cwq->pool consistent for sanity. | |
1707 | */ | |
1708 | if (std_worker_pool_pri(worker->pool)) | |
1709 | wq = system_highpri_wq; | |
1710 | else | |
1711 | wq = system_wq; | |
1712 | ||
1713 | insert_work(get_cwq(pool->cpu, wq), rebind_work, | |
1714 | worker->scheduled.next, | |
1715 | work_color_to_flags(WORK_NO_COLOR)); | |
ec58815a | 1716 | } |
25511a47 TH |
1717 | } |
1718 | ||
c34056a3 TH |
1719 | static struct worker *alloc_worker(void) |
1720 | { | |
1721 | struct worker *worker; | |
1722 | ||
1723 | worker = kzalloc(sizeof(*worker), GFP_KERNEL); | |
c8e55f36 TH |
1724 | if (worker) { |
1725 | INIT_LIST_HEAD(&worker->entry); | |
affee4b2 | 1726 | INIT_LIST_HEAD(&worker->scheduled); |
25511a47 | 1727 | INIT_WORK(&worker->rebind_work, busy_worker_rebind_fn); |
e22bee78 TH |
1728 | /* on creation a worker is in !idle && prep state */ |
1729 | worker->flags = WORKER_PREP; | |
c8e55f36 | 1730 | } |
c34056a3 TH |
1731 | return worker; |
1732 | } | |
1733 | ||
1734 | /** | |
1735 | * create_worker - create a new workqueue worker | |
63d95a91 | 1736 | * @pool: pool the new worker will belong to |
c34056a3 | 1737 | * |
63d95a91 | 1738 | * Create a new worker which is bound to @pool. The returned worker |
c34056a3 TH |
1739 | * can be started by calling start_worker() or destroyed using |
1740 | * destroy_worker(). | |
1741 | * | |
1742 | * CONTEXT: | |
1743 | * Might sleep. Does GFP_KERNEL allocations. | |
1744 | * | |
1745 | * RETURNS: | |
1746 | * Pointer to the newly created worker. | |
1747 | */ | |
bc2ae0f5 | 1748 | static struct worker *create_worker(struct worker_pool *pool) |
c34056a3 | 1749 | { |
e34cdddb | 1750 | const char *pri = std_worker_pool_pri(pool) ? "H" : ""; |
c34056a3 | 1751 | struct worker *worker = NULL; |
f3421797 | 1752 | int id = -1; |
c34056a3 | 1753 | |
d565ed63 | 1754 | spin_lock_irq(&pool->lock); |
bd7bdd43 | 1755 | while (ida_get_new(&pool->worker_ida, &id)) { |
d565ed63 | 1756 | spin_unlock_irq(&pool->lock); |
bd7bdd43 | 1757 | if (!ida_pre_get(&pool->worker_ida, GFP_KERNEL)) |
c34056a3 | 1758 | goto fail; |
d565ed63 | 1759 | spin_lock_irq(&pool->lock); |
c34056a3 | 1760 | } |
d565ed63 | 1761 | spin_unlock_irq(&pool->lock); |
c34056a3 TH |
1762 | |
1763 | worker = alloc_worker(); | |
1764 | if (!worker) | |
1765 | goto fail; | |
1766 | ||
bd7bdd43 | 1767 | worker->pool = pool; |
c34056a3 TH |
1768 | worker->id = id; |
1769 | ||
ec22ca5e | 1770 | if (pool->cpu != WORK_CPU_UNBOUND) |
94dcf29a | 1771 | worker->task = kthread_create_on_node(worker_thread, |
ec22ca5e TH |
1772 | worker, cpu_to_node(pool->cpu), |
1773 | "kworker/%u:%d%s", pool->cpu, id, pri); | |
f3421797 TH |
1774 | else |
1775 | worker->task = kthread_create(worker_thread, worker, | |
3270476a | 1776 | "kworker/u:%d%s", id, pri); |
c34056a3 TH |
1777 | if (IS_ERR(worker->task)) |
1778 | goto fail; | |
1779 | ||
e34cdddb | 1780 | if (std_worker_pool_pri(pool)) |
3270476a TH |
1781 | set_user_nice(worker->task, HIGHPRI_NICE_LEVEL); |
1782 | ||
db7bccf4 | 1783 | /* |
bc2ae0f5 | 1784 | * Determine CPU binding of the new worker depending on |
24647570 | 1785 | * %POOL_DISASSOCIATED. The caller is responsible for ensuring the |
bc2ae0f5 TH |
1786 | * flag remains stable across this function. See the comments |
1787 | * above the flag definition for details. | |
1788 | * | |
1789 | * As an unbound worker may later become a regular one if CPU comes | |
1790 | * online, make sure every worker has %PF_THREAD_BOUND set. | |
db7bccf4 | 1791 | */ |
24647570 | 1792 | if (!(pool->flags & POOL_DISASSOCIATED)) { |
ec22ca5e | 1793 | kthread_bind(worker->task, pool->cpu); |
bc2ae0f5 | 1794 | } else { |
db7bccf4 | 1795 | worker->task->flags |= PF_THREAD_BOUND; |
bc2ae0f5 | 1796 | worker->flags |= WORKER_UNBOUND; |
f3421797 | 1797 | } |
c34056a3 TH |
1798 | |
1799 | return worker; | |
1800 | fail: | |
1801 | if (id >= 0) { | |
d565ed63 | 1802 | spin_lock_irq(&pool->lock); |
bd7bdd43 | 1803 | ida_remove(&pool->worker_ida, id); |
d565ed63 | 1804 | spin_unlock_irq(&pool->lock); |
c34056a3 TH |
1805 | } |
1806 | kfree(worker); | |
1807 | return NULL; | |
1808 | } | |
1809 | ||
1810 | /** | |
1811 | * start_worker - start a newly created worker | |
1812 | * @worker: worker to start | |
1813 | * | |
706026c2 | 1814 | * Make the pool aware of @worker and start it. |
c34056a3 TH |
1815 | * |
1816 | * CONTEXT: | |
d565ed63 | 1817 | * spin_lock_irq(pool->lock). |
c34056a3 TH |
1818 | */ |
1819 | static void start_worker(struct worker *worker) | |
1820 | { | |
cb444766 | 1821 | worker->flags |= WORKER_STARTED; |
bd7bdd43 | 1822 | worker->pool->nr_workers++; |
c8e55f36 | 1823 | worker_enter_idle(worker); |
c34056a3 TH |
1824 | wake_up_process(worker->task); |
1825 | } | |
1826 | ||
1827 | /** | |
1828 | * destroy_worker - destroy a workqueue worker | |
1829 | * @worker: worker to be destroyed | |
1830 | * | |
706026c2 | 1831 | * Destroy @worker and adjust @pool stats accordingly. |
c8e55f36 TH |
1832 | * |
1833 | * CONTEXT: | |
d565ed63 | 1834 | * spin_lock_irq(pool->lock) which is released and regrabbed. |
c34056a3 TH |
1835 | */ |
1836 | static void destroy_worker(struct worker *worker) | |
1837 | { | |
bd7bdd43 | 1838 | struct worker_pool *pool = worker->pool; |
c34056a3 TH |
1839 | int id = worker->id; |
1840 | ||
1841 | /* sanity check frenzy */ | |
1842 | BUG_ON(worker->current_work); | |
affee4b2 | 1843 | BUG_ON(!list_empty(&worker->scheduled)); |
c34056a3 | 1844 | |
c8e55f36 | 1845 | if (worker->flags & WORKER_STARTED) |
bd7bdd43 | 1846 | pool->nr_workers--; |
c8e55f36 | 1847 | if (worker->flags & WORKER_IDLE) |
bd7bdd43 | 1848 | pool->nr_idle--; |
c8e55f36 TH |
1849 | |
1850 | list_del_init(&worker->entry); | |
cb444766 | 1851 | worker->flags |= WORKER_DIE; |
c8e55f36 | 1852 | |
d565ed63 | 1853 | spin_unlock_irq(&pool->lock); |
c8e55f36 | 1854 | |
c34056a3 TH |
1855 | kthread_stop(worker->task); |
1856 | kfree(worker); | |
1857 | ||
d565ed63 | 1858 | spin_lock_irq(&pool->lock); |
bd7bdd43 | 1859 | ida_remove(&pool->worker_ida, id); |
c34056a3 TH |
1860 | } |
1861 | ||
63d95a91 | 1862 | static void idle_worker_timeout(unsigned long __pool) |
e22bee78 | 1863 | { |
63d95a91 | 1864 | struct worker_pool *pool = (void *)__pool; |
e22bee78 | 1865 | |
d565ed63 | 1866 | spin_lock_irq(&pool->lock); |
e22bee78 | 1867 | |
63d95a91 | 1868 | if (too_many_workers(pool)) { |
e22bee78 TH |
1869 | struct worker *worker; |
1870 | unsigned long expires; | |
1871 | ||
1872 | /* idle_list is kept in LIFO order, check the last one */ | |
63d95a91 | 1873 | worker = list_entry(pool->idle_list.prev, struct worker, entry); |
e22bee78 TH |
1874 | expires = worker->last_active + IDLE_WORKER_TIMEOUT; |
1875 | ||
1876 | if (time_before(jiffies, expires)) | |
63d95a91 | 1877 | mod_timer(&pool->idle_timer, expires); |
e22bee78 TH |
1878 | else { |
1879 | /* it's been idle for too long, wake up manager */ | |
11ebea50 | 1880 | pool->flags |= POOL_MANAGE_WORKERS; |
63d95a91 | 1881 | wake_up_worker(pool); |
d5abe669 | 1882 | } |
e22bee78 TH |
1883 | } |
1884 | ||
d565ed63 | 1885 | spin_unlock_irq(&pool->lock); |
e22bee78 | 1886 | } |
d5abe669 | 1887 | |
e22bee78 TH |
1888 | static bool send_mayday(struct work_struct *work) |
1889 | { | |
1890 | struct cpu_workqueue_struct *cwq = get_work_cwq(work); | |
1891 | struct workqueue_struct *wq = cwq->wq; | |
f3421797 | 1892 | unsigned int cpu; |
e22bee78 TH |
1893 | |
1894 | if (!(wq->flags & WQ_RESCUER)) | |
1895 | return false; | |
1896 | ||
1897 | /* mayday mayday mayday */ | |
ec22ca5e | 1898 | cpu = cwq->pool->cpu; |
f3421797 TH |
1899 | /* WORK_CPU_UNBOUND can't be set in cpumask, use cpu 0 instead */ |
1900 | if (cpu == WORK_CPU_UNBOUND) | |
1901 | cpu = 0; | |
f2e005aa | 1902 | if (!mayday_test_and_set_cpu(cpu, wq->mayday_mask)) |
e22bee78 TH |
1903 | wake_up_process(wq->rescuer->task); |
1904 | return true; | |
1905 | } | |
1906 | ||
706026c2 | 1907 | static void pool_mayday_timeout(unsigned long __pool) |
e22bee78 | 1908 | { |
63d95a91 | 1909 | struct worker_pool *pool = (void *)__pool; |
e22bee78 TH |
1910 | struct work_struct *work; |
1911 | ||
d565ed63 | 1912 | spin_lock_irq(&pool->lock); |
e22bee78 | 1913 | |
63d95a91 | 1914 | if (need_to_create_worker(pool)) { |
e22bee78 TH |
1915 | /* |
1916 | * We've been trying to create a new worker but | |
1917 | * haven't been successful. We might be hitting an | |
1918 | * allocation deadlock. Send distress signals to | |
1919 | * rescuers. | |
1920 | */ | |
63d95a91 | 1921 | list_for_each_entry(work, &pool->worklist, entry) |
e22bee78 | 1922 | send_mayday(work); |
1da177e4 | 1923 | } |
e22bee78 | 1924 | |
d565ed63 | 1925 | spin_unlock_irq(&pool->lock); |
e22bee78 | 1926 | |
63d95a91 | 1927 | mod_timer(&pool->mayday_timer, jiffies + MAYDAY_INTERVAL); |
1da177e4 LT |
1928 | } |
1929 | ||
e22bee78 TH |
1930 | /** |
1931 | * maybe_create_worker - create a new worker if necessary | |
63d95a91 | 1932 | * @pool: pool to create a new worker for |
e22bee78 | 1933 | * |
63d95a91 | 1934 | * Create a new worker for @pool if necessary. @pool is guaranteed to |
e22bee78 TH |
1935 | * have at least one idle worker on return from this function. If |
1936 | * creating a new worker takes longer than MAYDAY_INTERVAL, mayday is | |
63d95a91 | 1937 | * sent to all rescuers with works scheduled on @pool to resolve |
e22bee78 TH |
1938 | * possible allocation deadlock. |
1939 | * | |
1940 | * On return, need_to_create_worker() is guaranteed to be false and | |
1941 | * may_start_working() true. | |
1942 | * | |
1943 | * LOCKING: | |
d565ed63 | 1944 | * spin_lock_irq(pool->lock) which may be released and regrabbed |
e22bee78 TH |
1945 | * multiple times. Does GFP_KERNEL allocations. Called only from |
1946 | * manager. | |
1947 | * | |
1948 | * RETURNS: | |
d565ed63 | 1949 | * false if no action was taken and pool->lock stayed locked, true |
e22bee78 TH |
1950 | * otherwise. |
1951 | */ | |
63d95a91 | 1952 | static bool maybe_create_worker(struct worker_pool *pool) |
d565ed63 TH |
1953 | __releases(&pool->lock) |
1954 | __acquires(&pool->lock) | |
1da177e4 | 1955 | { |
63d95a91 | 1956 | if (!need_to_create_worker(pool)) |
e22bee78 TH |
1957 | return false; |
1958 | restart: | |
d565ed63 | 1959 | spin_unlock_irq(&pool->lock); |
9f9c2364 | 1960 | |
e22bee78 | 1961 | /* if we don't make progress in MAYDAY_INITIAL_TIMEOUT, call for help */ |
63d95a91 | 1962 | mod_timer(&pool->mayday_timer, jiffies + MAYDAY_INITIAL_TIMEOUT); |
e22bee78 TH |
1963 | |
1964 | while (true) { | |
1965 | struct worker *worker; | |
1966 | ||
bc2ae0f5 | 1967 | worker = create_worker(pool); |
e22bee78 | 1968 | if (worker) { |
63d95a91 | 1969 | del_timer_sync(&pool->mayday_timer); |
d565ed63 | 1970 | spin_lock_irq(&pool->lock); |
e22bee78 | 1971 | start_worker(worker); |
63d95a91 | 1972 | BUG_ON(need_to_create_worker(pool)); |
e22bee78 TH |
1973 | return true; |
1974 | } | |
1975 | ||
63d95a91 | 1976 | if (!need_to_create_worker(pool)) |
e22bee78 | 1977 | break; |
1da177e4 | 1978 | |
e22bee78 TH |
1979 | __set_current_state(TASK_INTERRUPTIBLE); |
1980 | schedule_timeout(CREATE_COOLDOWN); | |
9f9c2364 | 1981 | |
63d95a91 | 1982 | if (!need_to_create_worker(pool)) |
e22bee78 TH |
1983 | break; |
1984 | } | |
1985 | ||
63d95a91 | 1986 | del_timer_sync(&pool->mayday_timer); |
d565ed63 | 1987 | spin_lock_irq(&pool->lock); |
63d95a91 | 1988 | if (need_to_create_worker(pool)) |
e22bee78 TH |
1989 | goto restart; |
1990 | return true; | |
1991 | } | |
1992 | ||
1993 | /** | |
1994 | * maybe_destroy_worker - destroy workers which have been idle for a while | |
63d95a91 | 1995 | * @pool: pool to destroy workers for |
e22bee78 | 1996 | * |
63d95a91 | 1997 | * Destroy @pool workers which have been idle for longer than |
e22bee78 TH |
1998 | * IDLE_WORKER_TIMEOUT. |
1999 | * | |
2000 | * LOCKING: | |
d565ed63 | 2001 | * spin_lock_irq(pool->lock) which may be released and regrabbed |
e22bee78 TH |
2002 | * multiple times. Called only from manager. |
2003 | * | |
2004 | * RETURNS: | |
d565ed63 | 2005 | * false if no action was taken and pool->lock stayed locked, true |
e22bee78 TH |
2006 | * otherwise. |
2007 | */ | |
63d95a91 | 2008 | static bool maybe_destroy_workers(struct worker_pool *pool) |
e22bee78 TH |
2009 | { |
2010 | bool ret = false; | |
1da177e4 | 2011 | |
63d95a91 | 2012 | while (too_many_workers(pool)) { |
e22bee78 TH |
2013 | struct worker *worker; |
2014 | unsigned long expires; | |
3af24433 | 2015 | |
63d95a91 | 2016 | worker = list_entry(pool->idle_list.prev, struct worker, entry); |
e22bee78 | 2017 | expires = worker->last_active + IDLE_WORKER_TIMEOUT; |
85f4186a | 2018 | |
e22bee78 | 2019 | if (time_before(jiffies, expires)) { |
63d95a91 | 2020 | mod_timer(&pool->idle_timer, expires); |
3af24433 | 2021 | break; |
e22bee78 | 2022 | } |
1da177e4 | 2023 | |
e22bee78 TH |
2024 | destroy_worker(worker); |
2025 | ret = true; | |
1da177e4 | 2026 | } |
1e19ffc6 | 2027 | |
e22bee78 | 2028 | return ret; |
1e19ffc6 TH |
2029 | } |
2030 | ||
73f53c4a | 2031 | /** |
e22bee78 TH |
2032 | * manage_workers - manage worker pool |
2033 | * @worker: self | |
73f53c4a | 2034 | * |
706026c2 | 2035 | * Assume the manager role and manage the worker pool @worker belongs |
e22bee78 | 2036 | * to. At any given time, there can be only zero or one manager per |
706026c2 | 2037 | * pool. The exclusion is handled automatically by this function. |
e22bee78 TH |
2038 | * |
2039 | * The caller can safely start processing works on false return. On | |
2040 | * true return, it's guaranteed that need_to_create_worker() is false | |
2041 | * and may_start_working() is true. | |
73f53c4a TH |
2042 | * |
2043 | * CONTEXT: | |
d565ed63 | 2044 | * spin_lock_irq(pool->lock) which may be released and regrabbed |
e22bee78 TH |
2045 | * multiple times. Does GFP_KERNEL allocations. |
2046 | * | |
2047 | * RETURNS: | |
d565ed63 TH |
2048 | * spin_lock_irq(pool->lock) which may be released and regrabbed |
2049 | * multiple times. Does GFP_KERNEL allocations. | |
73f53c4a | 2050 | */ |
e22bee78 | 2051 | static bool manage_workers(struct worker *worker) |
73f53c4a | 2052 | { |
63d95a91 | 2053 | struct worker_pool *pool = worker->pool; |
e22bee78 | 2054 | bool ret = false; |
73f53c4a | 2055 | |
ee378aa4 | 2056 | if (pool->flags & POOL_MANAGING_WORKERS) |
e22bee78 | 2057 | return ret; |
1e19ffc6 | 2058 | |
552a37e9 | 2059 | pool->flags |= POOL_MANAGING_WORKERS; |
73f53c4a | 2060 | |
ee378aa4 LJ |
2061 | /* |
2062 | * To simplify both worker management and CPU hotplug, hold off | |
2063 | * management while hotplug is in progress. CPU hotplug path can't | |
2064 | * grab %POOL_MANAGING_WORKERS to achieve this because that can | |
2065 | * lead to idle worker depletion (all become busy thinking someone | |
2066 | * else is managing) which in turn can result in deadlock under | |
b2eb83d1 | 2067 | * extreme circumstances. Use @pool->assoc_mutex to synchronize |
ee378aa4 LJ |
2068 | * manager against CPU hotplug. |
2069 | * | |
b2eb83d1 | 2070 | * assoc_mutex would always be free unless CPU hotplug is in |
d565ed63 | 2071 | * progress. trylock first without dropping @pool->lock. |
ee378aa4 | 2072 | */ |
b2eb83d1 | 2073 | if (unlikely(!mutex_trylock(&pool->assoc_mutex))) { |
d565ed63 | 2074 | spin_unlock_irq(&pool->lock); |
b2eb83d1 | 2075 | mutex_lock(&pool->assoc_mutex); |
ee378aa4 LJ |
2076 | /* |
2077 | * CPU hotplug could have happened while we were waiting | |
b2eb83d1 | 2078 | * for assoc_mutex. Hotplug itself can't handle us |
ee378aa4 | 2079 | * because manager isn't either on idle or busy list, and |
706026c2 | 2080 | * @pool's state and ours could have deviated. |
ee378aa4 | 2081 | * |
b2eb83d1 | 2082 | * As hotplug is now excluded via assoc_mutex, we can |
ee378aa4 | 2083 | * simply try to bind. It will succeed or fail depending |
706026c2 | 2084 | * on @pool's current state. Try it and adjust |
ee378aa4 LJ |
2085 | * %WORKER_UNBOUND accordingly. |
2086 | */ | |
2087 | if (worker_maybe_bind_and_lock(worker)) | |
2088 | worker->flags &= ~WORKER_UNBOUND; | |
2089 | else | |
2090 | worker->flags |= WORKER_UNBOUND; | |
73f53c4a | 2091 | |
ee378aa4 LJ |
2092 | ret = true; |
2093 | } | |
73f53c4a | 2094 | |
11ebea50 | 2095 | pool->flags &= ~POOL_MANAGE_WORKERS; |
73f53c4a TH |
2096 | |
2097 | /* | |
e22bee78 TH |
2098 | * Destroy and then create so that may_start_working() is true |
2099 | * on return. | |
73f53c4a | 2100 | */ |
63d95a91 TH |
2101 | ret |= maybe_destroy_workers(pool); |
2102 | ret |= maybe_create_worker(pool); | |
e22bee78 | 2103 | |
552a37e9 | 2104 | pool->flags &= ~POOL_MANAGING_WORKERS; |
b2eb83d1 | 2105 | mutex_unlock(&pool->assoc_mutex); |
e22bee78 | 2106 | return ret; |
73f53c4a TH |
2107 | } |
2108 | ||
a62428c0 TH |
2109 | /** |
2110 | * process_one_work - process single work | |
c34056a3 | 2111 | * @worker: self |
a62428c0 TH |
2112 | * @work: work to process |
2113 | * | |
2114 | * Process @work. This function contains all the logics necessary to | |
2115 | * process a single work including synchronization against and | |
2116 | * interaction with other workers on the same cpu, queueing and | |
2117 | * flushing. As long as context requirement is met, any worker can | |
2118 | * call this function to process a work. | |
2119 | * | |
2120 | * CONTEXT: | |
d565ed63 | 2121 | * spin_lock_irq(pool->lock) which is released and regrabbed. |
a62428c0 | 2122 | */ |
c34056a3 | 2123 | static void process_one_work(struct worker *worker, struct work_struct *work) |
d565ed63 TH |
2124 | __releases(&pool->lock) |
2125 | __acquires(&pool->lock) | |
a62428c0 | 2126 | { |
7e11629d | 2127 | struct cpu_workqueue_struct *cwq = get_work_cwq(work); |
bd7bdd43 | 2128 | struct worker_pool *pool = worker->pool; |
fb0e7beb | 2129 | bool cpu_intensive = cwq->wq->flags & WQ_CPU_INTENSIVE; |
73f53c4a | 2130 | int work_color; |
7e11629d | 2131 | struct worker *collision; |
a62428c0 TH |
2132 | #ifdef CONFIG_LOCKDEP |
2133 | /* | |
2134 | * It is permissible to free the struct work_struct from | |
2135 | * inside the function that is called from it, this we need to | |
2136 | * take into account for lockdep too. To avoid bogus "held | |
2137 | * lock freed" warnings as well as problems when looking into | |
2138 | * work->lockdep_map, make a copy and use that here. | |
2139 | */ | |
4d82a1de PZ |
2140 | struct lockdep_map lockdep_map; |
2141 | ||
2142 | lockdep_copy_map(&lockdep_map, &work->lockdep_map); | |
a62428c0 | 2143 | #endif |
6fec10a1 TH |
2144 | /* |
2145 | * Ensure we're on the correct CPU. DISASSOCIATED test is | |
2146 | * necessary to avoid spurious warnings from rescuers servicing the | |
24647570 | 2147 | * unbound or a disassociated pool. |
6fec10a1 | 2148 | */ |
5f7dabfd | 2149 | WARN_ON_ONCE(!(worker->flags & WORKER_UNBOUND) && |
24647570 | 2150 | !(pool->flags & POOL_DISASSOCIATED) && |
ec22ca5e | 2151 | raw_smp_processor_id() != pool->cpu); |
25511a47 | 2152 | |
7e11629d TH |
2153 | /* |
2154 | * A single work shouldn't be executed concurrently by | |
2155 | * multiple workers on a single cpu. Check whether anyone is | |
2156 | * already processing the work. If so, defer the work to the | |
2157 | * currently executing one. | |
2158 | */ | |
c9e7cf27 | 2159 | collision = find_worker_executing_work(pool, work); |
7e11629d TH |
2160 | if (unlikely(collision)) { |
2161 | move_linked_works(work, &collision->scheduled, NULL); | |
2162 | return; | |
2163 | } | |
2164 | ||
8930caba | 2165 | /* claim and dequeue */ |
a62428c0 | 2166 | debug_work_deactivate(work); |
c9e7cf27 | 2167 | hash_add(pool->busy_hash, &worker->hentry, (unsigned long)work); |
c34056a3 | 2168 | worker->current_work = work; |
a2c1c57b | 2169 | worker->current_func = work->func; |
8cca0eea | 2170 | worker->current_cwq = cwq; |
73f53c4a | 2171 | work_color = get_work_color(work); |
7a22ad75 | 2172 | |
a62428c0 TH |
2173 | list_del_init(&work->entry); |
2174 | ||
fb0e7beb TH |
2175 | /* |
2176 | * CPU intensive works don't participate in concurrency | |
2177 | * management. They're the scheduler's responsibility. | |
2178 | */ | |
2179 | if (unlikely(cpu_intensive)) | |
2180 | worker_set_flags(worker, WORKER_CPU_INTENSIVE, true); | |
2181 | ||
974271c4 | 2182 | /* |
d565ed63 | 2183 | * Unbound pool isn't concurrency managed and work items should be |
974271c4 TH |
2184 | * executed ASAP. Wake up another worker if necessary. |
2185 | */ | |
63d95a91 TH |
2186 | if ((worker->flags & WORKER_UNBOUND) && need_more_worker(pool)) |
2187 | wake_up_worker(pool); | |
974271c4 | 2188 | |
8930caba | 2189 | /* |
7c3eed5c | 2190 | * Record the last pool and clear PENDING which should be the last |
d565ed63 | 2191 | * update to @work. Also, do this inside @pool->lock so that |
23657bb1 TH |
2192 | * PENDING and queued state changes happen together while IRQ is |
2193 | * disabled. | |
8930caba | 2194 | */ |
7c3eed5c | 2195 | set_work_pool_and_clear_pending(work, pool->id); |
a62428c0 | 2196 | |
d565ed63 | 2197 | spin_unlock_irq(&pool->lock); |
a62428c0 | 2198 | |
e159489b | 2199 | lock_map_acquire_read(&cwq->wq->lockdep_map); |
a62428c0 | 2200 | lock_map_acquire(&lockdep_map); |
e36c886a | 2201 | trace_workqueue_execute_start(work); |
a2c1c57b | 2202 | worker->current_func(work); |
e36c886a AV |
2203 | /* |
2204 | * While we must be careful to not use "work" after this, the trace | |
2205 | * point will only record its address. | |
2206 | */ | |
2207 | trace_workqueue_execute_end(work); | |
a62428c0 TH |
2208 | lock_map_release(&lockdep_map); |
2209 | lock_map_release(&cwq->wq->lockdep_map); | |
2210 | ||
2211 | if (unlikely(in_atomic() || lockdep_depth(current) > 0)) { | |
044c782c VI |
2212 | pr_err("BUG: workqueue leaked lock or atomic: %s/0x%08x/%d\n" |
2213 | " last function: %pf\n", | |
a2c1c57b TH |
2214 | current->comm, preempt_count(), task_pid_nr(current), |
2215 | worker->current_func); | |
a62428c0 TH |
2216 | debug_show_held_locks(current); |
2217 | dump_stack(); | |
2218 | } | |
2219 | ||
d565ed63 | 2220 | spin_lock_irq(&pool->lock); |
a62428c0 | 2221 | |
fb0e7beb TH |
2222 | /* clear cpu intensive status */ |
2223 | if (unlikely(cpu_intensive)) | |
2224 | worker_clr_flags(worker, WORKER_CPU_INTENSIVE); | |
2225 | ||
a62428c0 | 2226 | /* we're done with it, release */ |
42f8570f | 2227 | hash_del(&worker->hentry); |
c34056a3 | 2228 | worker->current_work = NULL; |
a2c1c57b | 2229 | worker->current_func = NULL; |
8cca0eea | 2230 | worker->current_cwq = NULL; |
b3f9f405 | 2231 | cwq_dec_nr_in_flight(cwq, work_color); |
a62428c0 TH |
2232 | } |
2233 | ||
affee4b2 TH |
2234 | /** |
2235 | * process_scheduled_works - process scheduled works | |
2236 | * @worker: self | |
2237 | * | |
2238 | * Process all scheduled works. Please note that the scheduled list | |
2239 | * may change while processing a work, so this function repeatedly | |
2240 | * fetches a work from the top and executes it. | |
2241 | * | |
2242 | * CONTEXT: | |
d565ed63 | 2243 | * spin_lock_irq(pool->lock) which may be released and regrabbed |
affee4b2 TH |
2244 | * multiple times. |
2245 | */ | |
2246 | static void process_scheduled_works(struct worker *worker) | |
1da177e4 | 2247 | { |
affee4b2 TH |
2248 | while (!list_empty(&worker->scheduled)) { |
2249 | struct work_struct *work = list_first_entry(&worker->scheduled, | |
1da177e4 | 2250 | struct work_struct, entry); |
c34056a3 | 2251 | process_one_work(worker, work); |
1da177e4 | 2252 | } |
1da177e4 LT |
2253 | } |
2254 | ||
4690c4ab TH |
2255 | /** |
2256 | * worker_thread - the worker thread function | |
c34056a3 | 2257 | * @__worker: self |
4690c4ab | 2258 | * |
706026c2 TH |
2259 | * The worker thread function. There are NR_CPU_WORKER_POOLS dynamic pools |
2260 | * of these per each cpu. These workers process all works regardless of | |
e22bee78 TH |
2261 | * their specific target workqueue. The only exception is works which |
2262 | * belong to workqueues with a rescuer which will be explained in | |
2263 | * rescuer_thread(). | |
4690c4ab | 2264 | */ |
c34056a3 | 2265 | static int worker_thread(void *__worker) |
1da177e4 | 2266 | { |
c34056a3 | 2267 | struct worker *worker = __worker; |
bd7bdd43 | 2268 | struct worker_pool *pool = worker->pool; |
1da177e4 | 2269 | |
e22bee78 TH |
2270 | /* tell the scheduler that this is a workqueue worker */ |
2271 | worker->task->flags |= PF_WQ_WORKER; | |
c8e55f36 | 2272 | woke_up: |
d565ed63 | 2273 | spin_lock_irq(&pool->lock); |
1da177e4 | 2274 | |
5f7dabfd LJ |
2275 | /* we are off idle list if destruction or rebind is requested */ |
2276 | if (unlikely(list_empty(&worker->entry))) { | |
d565ed63 | 2277 | spin_unlock_irq(&pool->lock); |
25511a47 | 2278 | |
5f7dabfd | 2279 | /* if DIE is set, destruction is requested */ |
25511a47 TH |
2280 | if (worker->flags & WORKER_DIE) { |
2281 | worker->task->flags &= ~PF_WQ_WORKER; | |
2282 | return 0; | |
2283 | } | |
2284 | ||
5f7dabfd | 2285 | /* otherwise, rebind */ |
25511a47 TH |
2286 | idle_worker_rebind(worker); |
2287 | goto woke_up; | |
c8e55f36 | 2288 | } |
affee4b2 | 2289 | |
c8e55f36 | 2290 | worker_leave_idle(worker); |
db7bccf4 | 2291 | recheck: |
e22bee78 | 2292 | /* no more worker necessary? */ |
63d95a91 | 2293 | if (!need_more_worker(pool)) |
e22bee78 TH |
2294 | goto sleep; |
2295 | ||
2296 | /* do we need to manage? */ | |
63d95a91 | 2297 | if (unlikely(!may_start_working(pool)) && manage_workers(worker)) |
e22bee78 TH |
2298 | goto recheck; |
2299 | ||
c8e55f36 TH |
2300 | /* |
2301 | * ->scheduled list can only be filled while a worker is | |
2302 | * preparing to process a work or actually processing it. | |
2303 | * Make sure nobody diddled with it while I was sleeping. | |
2304 | */ | |
2305 | BUG_ON(!list_empty(&worker->scheduled)); | |
2306 | ||
e22bee78 TH |
2307 | /* |
2308 | * When control reaches this point, we're guaranteed to have | |
2309 | * at least one idle worker or that someone else has already | |
2310 | * assumed the manager role. | |
2311 | */ | |
2312 | worker_clr_flags(worker, WORKER_PREP); | |
2313 | ||
2314 | do { | |
c8e55f36 | 2315 | struct work_struct *work = |
bd7bdd43 | 2316 | list_first_entry(&pool->worklist, |
c8e55f36 TH |
2317 | struct work_struct, entry); |
2318 | ||
2319 | if (likely(!(*work_data_bits(work) & WORK_STRUCT_LINKED))) { | |
2320 | /* optimization path, not strictly necessary */ | |
2321 | process_one_work(worker, work); | |
2322 | if (unlikely(!list_empty(&worker->scheduled))) | |
affee4b2 | 2323 | process_scheduled_works(worker); |
c8e55f36 TH |
2324 | } else { |
2325 | move_linked_works(work, &worker->scheduled, NULL); | |
2326 | process_scheduled_works(worker); | |
affee4b2 | 2327 | } |
63d95a91 | 2328 | } while (keep_working(pool)); |
e22bee78 TH |
2329 | |
2330 | worker_set_flags(worker, WORKER_PREP, false); | |
d313dd85 | 2331 | sleep: |
63d95a91 | 2332 | if (unlikely(need_to_manage_workers(pool)) && manage_workers(worker)) |
e22bee78 | 2333 | goto recheck; |
d313dd85 | 2334 | |
c8e55f36 | 2335 | /* |
d565ed63 TH |
2336 | * pool->lock is held and there's no work to process and no need to |
2337 | * manage, sleep. Workers are woken up only while holding | |
2338 | * pool->lock or from local cpu, so setting the current state | |
2339 | * before releasing pool->lock is enough to prevent losing any | |
2340 | * event. | |
c8e55f36 TH |
2341 | */ |
2342 | worker_enter_idle(worker); | |
2343 | __set_current_state(TASK_INTERRUPTIBLE); | |
d565ed63 | 2344 | spin_unlock_irq(&pool->lock); |
c8e55f36 TH |
2345 | schedule(); |
2346 | goto woke_up; | |
1da177e4 LT |
2347 | } |
2348 | ||
e22bee78 TH |
2349 | /** |
2350 | * rescuer_thread - the rescuer thread function | |
111c225a | 2351 | * @__rescuer: self |
e22bee78 TH |
2352 | * |
2353 | * Workqueue rescuer thread function. There's one rescuer for each | |
2354 | * workqueue which has WQ_RESCUER set. | |
2355 | * | |
706026c2 | 2356 | * Regular work processing on a pool may block trying to create a new |
e22bee78 TH |
2357 | * worker which uses GFP_KERNEL allocation which has slight chance of |
2358 | * developing into deadlock if some works currently on the same queue | |
2359 | * need to be processed to satisfy the GFP_KERNEL allocation. This is | |
2360 | * the problem rescuer solves. | |
2361 | * | |
706026c2 TH |
2362 | * When such condition is possible, the pool summons rescuers of all |
2363 | * workqueues which have works queued on the pool and let them process | |
e22bee78 TH |
2364 | * those works so that forward progress can be guaranteed. |
2365 | * | |
2366 | * This should happen rarely. | |
2367 | */ | |
111c225a | 2368 | static int rescuer_thread(void *__rescuer) |
e22bee78 | 2369 | { |
111c225a TH |
2370 | struct worker *rescuer = __rescuer; |
2371 | struct workqueue_struct *wq = rescuer->rescue_wq; | |
e22bee78 | 2372 | struct list_head *scheduled = &rescuer->scheduled; |
f3421797 | 2373 | bool is_unbound = wq->flags & WQ_UNBOUND; |
e22bee78 TH |
2374 | unsigned int cpu; |
2375 | ||
2376 | set_user_nice(current, RESCUER_NICE_LEVEL); | |
111c225a TH |
2377 | |
2378 | /* | |
2379 | * Mark rescuer as worker too. As WORKER_PREP is never cleared, it | |
2380 | * doesn't participate in concurrency management. | |
2381 | */ | |
2382 | rescuer->task->flags |= PF_WQ_WORKER; | |
e22bee78 TH |
2383 | repeat: |
2384 | set_current_state(TASK_INTERRUPTIBLE); | |
2385 | ||
412d32e6 MG |
2386 | if (kthread_should_stop()) { |
2387 | __set_current_state(TASK_RUNNING); | |
111c225a | 2388 | rescuer->task->flags &= ~PF_WQ_WORKER; |
e22bee78 | 2389 | return 0; |
412d32e6 | 2390 | } |
e22bee78 | 2391 | |
f3421797 TH |
2392 | /* |
2393 | * See whether any cpu is asking for help. Unbounded | |
2394 | * workqueues use cpu 0 in mayday_mask for CPU_UNBOUND. | |
2395 | */ | |
f2e005aa | 2396 | for_each_mayday_cpu(cpu, wq->mayday_mask) { |
f3421797 TH |
2397 | unsigned int tcpu = is_unbound ? WORK_CPU_UNBOUND : cpu; |
2398 | struct cpu_workqueue_struct *cwq = get_cwq(tcpu, wq); | |
bd7bdd43 | 2399 | struct worker_pool *pool = cwq->pool; |
e22bee78 TH |
2400 | struct work_struct *work, *n; |
2401 | ||
2402 | __set_current_state(TASK_RUNNING); | |
f2e005aa | 2403 | mayday_clear_cpu(cpu, wq->mayday_mask); |
e22bee78 TH |
2404 | |
2405 | /* migrate to the target cpu if possible */ | |
bd7bdd43 | 2406 | rescuer->pool = pool; |
e22bee78 TH |
2407 | worker_maybe_bind_and_lock(rescuer); |
2408 | ||
2409 | /* | |
2410 | * Slurp in all works issued via this workqueue and | |
2411 | * process'em. | |
2412 | */ | |
2413 | BUG_ON(!list_empty(&rescuer->scheduled)); | |
bd7bdd43 | 2414 | list_for_each_entry_safe(work, n, &pool->worklist, entry) |
e22bee78 TH |
2415 | if (get_work_cwq(work) == cwq) |
2416 | move_linked_works(work, scheduled, &n); | |
2417 | ||
2418 | process_scheduled_works(rescuer); | |
7576958a TH |
2419 | |
2420 | /* | |
d565ed63 | 2421 | * Leave this pool. If keep_working() is %true, notify a |
7576958a TH |
2422 | * regular worker; otherwise, we end up with 0 concurrency |
2423 | * and stalling the execution. | |
2424 | */ | |
63d95a91 TH |
2425 | if (keep_working(pool)) |
2426 | wake_up_worker(pool); | |
7576958a | 2427 | |
d565ed63 | 2428 | spin_unlock_irq(&pool->lock); |
e22bee78 TH |
2429 | } |
2430 | ||
111c225a TH |
2431 | /* rescuers should never participate in concurrency management */ |
2432 | WARN_ON_ONCE(!(rescuer->flags & WORKER_NOT_RUNNING)); | |
e22bee78 TH |
2433 | schedule(); |
2434 | goto repeat; | |
1da177e4 LT |
2435 | } |
2436 | ||
fc2e4d70 ON |
2437 | struct wq_barrier { |
2438 | struct work_struct work; | |
2439 | struct completion done; | |
2440 | }; | |
2441 | ||
2442 | static void wq_barrier_func(struct work_struct *work) | |
2443 | { | |
2444 | struct wq_barrier *barr = container_of(work, struct wq_barrier, work); | |
2445 | complete(&barr->done); | |
2446 | } | |
2447 | ||
4690c4ab TH |
2448 | /** |
2449 | * insert_wq_barrier - insert a barrier work | |
2450 | * @cwq: cwq to insert barrier into | |
2451 | * @barr: wq_barrier to insert | |
affee4b2 TH |
2452 | * @target: target work to attach @barr to |
2453 | * @worker: worker currently executing @target, NULL if @target is not executing | |
4690c4ab | 2454 | * |
affee4b2 TH |
2455 | * @barr is linked to @target such that @barr is completed only after |
2456 | * @target finishes execution. Please note that the ordering | |
2457 | * guarantee is observed only with respect to @target and on the local | |
2458 | * cpu. | |
2459 | * | |
2460 | * Currently, a queued barrier can't be canceled. This is because | |
2461 | * try_to_grab_pending() can't determine whether the work to be | |
2462 | * grabbed is at the head of the queue and thus can't clear LINKED | |
2463 | * flag of the previous work while there must be a valid next work | |
2464 | * after a work with LINKED flag set. | |
2465 | * | |
2466 | * Note that when @worker is non-NULL, @target may be modified | |
2467 | * underneath us, so we can't reliably determine cwq from @target. | |
4690c4ab TH |
2468 | * |
2469 | * CONTEXT: | |
d565ed63 | 2470 | * spin_lock_irq(pool->lock). |
4690c4ab | 2471 | */ |
83c22520 | 2472 | static void insert_wq_barrier(struct cpu_workqueue_struct *cwq, |
affee4b2 TH |
2473 | struct wq_barrier *barr, |
2474 | struct work_struct *target, struct worker *worker) | |
fc2e4d70 | 2475 | { |
affee4b2 TH |
2476 | struct list_head *head; |
2477 | unsigned int linked = 0; | |
2478 | ||
dc186ad7 | 2479 | /* |
d565ed63 | 2480 | * debugobject calls are safe here even with pool->lock locked |
dc186ad7 TG |
2481 | * as we know for sure that this will not trigger any of the |
2482 | * checks and call back into the fixup functions where we | |
2483 | * might deadlock. | |
2484 | */ | |
ca1cab37 | 2485 | INIT_WORK_ONSTACK(&barr->work, wq_barrier_func); |
22df02bb | 2486 | __set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(&barr->work)); |
fc2e4d70 | 2487 | init_completion(&barr->done); |
83c22520 | 2488 | |
affee4b2 TH |
2489 | /* |
2490 | * If @target is currently being executed, schedule the | |
2491 | * barrier to the worker; otherwise, put it after @target. | |
2492 | */ | |
2493 | if (worker) | |
2494 | head = worker->scheduled.next; | |
2495 | else { | |
2496 | unsigned long *bits = work_data_bits(target); | |
2497 | ||
2498 | head = target->entry.next; | |
2499 | /* there can already be other linked works, inherit and set */ | |
2500 | linked = *bits & WORK_STRUCT_LINKED; | |
2501 | __set_bit(WORK_STRUCT_LINKED_BIT, bits); | |
2502 | } | |
2503 | ||
dc186ad7 | 2504 | debug_work_activate(&barr->work); |
affee4b2 TH |
2505 | insert_work(cwq, &barr->work, head, |
2506 | work_color_to_flags(WORK_NO_COLOR) | linked); | |
fc2e4d70 ON |
2507 | } |
2508 | ||
73f53c4a TH |
2509 | /** |
2510 | * flush_workqueue_prep_cwqs - prepare cwqs for workqueue flushing | |
2511 | * @wq: workqueue being flushed | |
2512 | * @flush_color: new flush color, < 0 for no-op | |
2513 | * @work_color: new work color, < 0 for no-op | |
2514 | * | |
2515 | * Prepare cwqs for workqueue flushing. | |
2516 | * | |
2517 | * If @flush_color is non-negative, flush_color on all cwqs should be | |
2518 | * -1. If no cwq has in-flight commands at the specified color, all | |
2519 | * cwq->flush_color's stay at -1 and %false is returned. If any cwq | |
2520 | * has in flight commands, its cwq->flush_color is set to | |
2521 | * @flush_color, @wq->nr_cwqs_to_flush is updated accordingly, cwq | |
2522 | * wakeup logic is armed and %true is returned. | |
2523 | * | |
2524 | * The caller should have initialized @wq->first_flusher prior to | |
2525 | * calling this function with non-negative @flush_color. If | |
2526 | * @flush_color is negative, no flush color update is done and %false | |
2527 | * is returned. | |
2528 | * | |
2529 | * If @work_color is non-negative, all cwqs should have the same | |
2530 | * work_color which is previous to @work_color and all will be | |
2531 | * advanced to @work_color. | |
2532 | * | |
2533 | * CONTEXT: | |
2534 | * mutex_lock(wq->flush_mutex). | |
2535 | * | |
2536 | * RETURNS: | |
2537 | * %true if @flush_color >= 0 and there's something to flush. %false | |
2538 | * otherwise. | |
2539 | */ | |
2540 | static bool flush_workqueue_prep_cwqs(struct workqueue_struct *wq, | |
2541 | int flush_color, int work_color) | |
1da177e4 | 2542 | { |
73f53c4a TH |
2543 | bool wait = false; |
2544 | unsigned int cpu; | |
1da177e4 | 2545 | |
73f53c4a TH |
2546 | if (flush_color >= 0) { |
2547 | BUG_ON(atomic_read(&wq->nr_cwqs_to_flush)); | |
2548 | atomic_set(&wq->nr_cwqs_to_flush, 1); | |
1da177e4 | 2549 | } |
2355b70f | 2550 | |
f3421797 | 2551 | for_each_cwq_cpu(cpu, wq) { |
73f53c4a | 2552 | struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); |
d565ed63 | 2553 | struct worker_pool *pool = cwq->pool; |
fc2e4d70 | 2554 | |
d565ed63 | 2555 | spin_lock_irq(&pool->lock); |
83c22520 | 2556 | |
73f53c4a TH |
2557 | if (flush_color >= 0) { |
2558 | BUG_ON(cwq->flush_color != -1); | |
fc2e4d70 | 2559 | |
73f53c4a TH |
2560 | if (cwq->nr_in_flight[flush_color]) { |
2561 | cwq->flush_color = flush_color; | |
2562 | atomic_inc(&wq->nr_cwqs_to_flush); | |
2563 | wait = true; | |
2564 | } | |
2565 | } | |
1da177e4 | 2566 | |
73f53c4a TH |
2567 | if (work_color >= 0) { |
2568 | BUG_ON(work_color != work_next_color(cwq->work_color)); | |
2569 | cwq->work_color = work_color; | |
2570 | } | |
1da177e4 | 2571 | |
d565ed63 | 2572 | spin_unlock_irq(&pool->lock); |
1da177e4 | 2573 | } |
2355b70f | 2574 | |
73f53c4a TH |
2575 | if (flush_color >= 0 && atomic_dec_and_test(&wq->nr_cwqs_to_flush)) |
2576 | complete(&wq->first_flusher->done); | |
14441960 | 2577 | |
73f53c4a | 2578 | return wait; |
1da177e4 LT |
2579 | } |
2580 | ||
0fcb78c2 | 2581 | /** |
1da177e4 | 2582 | * flush_workqueue - ensure that any scheduled work has run to completion. |
0fcb78c2 | 2583 | * @wq: workqueue to flush |
1da177e4 LT |
2584 | * |
2585 | * Forces execution of the workqueue and blocks until its completion. | |
2586 | * This is typically used in driver shutdown handlers. | |
2587 | * | |
fc2e4d70 ON |
2588 | * We sleep until all works which were queued on entry have been handled, |
2589 | * but we are not livelocked by new incoming ones. | |
1da177e4 | 2590 | */ |
7ad5b3a5 | 2591 | void flush_workqueue(struct workqueue_struct *wq) |
1da177e4 | 2592 | { |
73f53c4a TH |
2593 | struct wq_flusher this_flusher = { |
2594 | .list = LIST_HEAD_INIT(this_flusher.list), | |
2595 | .flush_color = -1, | |
2596 | .done = COMPLETION_INITIALIZER_ONSTACK(this_flusher.done), | |
2597 | }; | |
2598 | int next_color; | |
1da177e4 | 2599 | |
3295f0ef IM |
2600 | lock_map_acquire(&wq->lockdep_map); |
2601 | lock_map_release(&wq->lockdep_map); | |
73f53c4a TH |
2602 | |
2603 | mutex_lock(&wq->flush_mutex); | |
2604 | ||
2605 | /* | |
2606 | * Start-to-wait phase | |
2607 | */ | |
2608 | next_color = work_next_color(wq->work_color); | |
2609 | ||
2610 | if (next_color != wq->flush_color) { | |
2611 | /* | |
2612 | * Color space is not full. The current work_color | |
2613 | * becomes our flush_color and work_color is advanced | |
2614 | * by one. | |
2615 | */ | |
2616 | BUG_ON(!list_empty(&wq->flusher_overflow)); | |
2617 | this_flusher.flush_color = wq->work_color; | |
2618 | wq->work_color = next_color; | |
2619 | ||
2620 | if (!wq->first_flusher) { | |
2621 | /* no flush in progress, become the first flusher */ | |
2622 | BUG_ON(wq->flush_color != this_flusher.flush_color); | |
2623 | ||
2624 | wq->first_flusher = &this_flusher; | |
2625 | ||
2626 | if (!flush_workqueue_prep_cwqs(wq, wq->flush_color, | |
2627 | wq->work_color)) { | |
2628 | /* nothing to flush, done */ | |
2629 | wq->flush_color = next_color; | |
2630 | wq->first_flusher = NULL; | |
2631 | goto out_unlock; | |
2632 | } | |
2633 | } else { | |
2634 | /* wait in queue */ | |
2635 | BUG_ON(wq->flush_color == this_flusher.flush_color); | |
2636 | list_add_tail(&this_flusher.list, &wq->flusher_queue); | |
2637 | flush_workqueue_prep_cwqs(wq, -1, wq->work_color); | |
2638 | } | |
2639 | } else { | |
2640 | /* | |
2641 | * Oops, color space is full, wait on overflow queue. | |
2642 | * The next flush completion will assign us | |
2643 | * flush_color and transfer to flusher_queue. | |
2644 | */ | |
2645 | list_add_tail(&this_flusher.list, &wq->flusher_overflow); | |
2646 | } | |
2647 | ||
2648 | mutex_unlock(&wq->flush_mutex); | |
2649 | ||
2650 | wait_for_completion(&this_flusher.done); | |
2651 | ||
2652 | /* | |
2653 | * Wake-up-and-cascade phase | |
2654 | * | |
2655 | * First flushers are responsible for cascading flushes and | |
2656 | * handling overflow. Non-first flushers can simply return. | |
2657 | */ | |
2658 | if (wq->first_flusher != &this_flusher) | |
2659 | return; | |
2660 | ||
2661 | mutex_lock(&wq->flush_mutex); | |
2662 | ||
4ce48b37 TH |
2663 | /* we might have raced, check again with mutex held */ |
2664 | if (wq->first_flusher != &this_flusher) | |
2665 | goto out_unlock; | |
2666 | ||
73f53c4a TH |
2667 | wq->first_flusher = NULL; |
2668 | ||
2669 | BUG_ON(!list_empty(&this_flusher.list)); | |
2670 | BUG_ON(wq->flush_color != this_flusher.flush_color); | |
2671 | ||
2672 | while (true) { | |
2673 | struct wq_flusher *next, *tmp; | |
2674 | ||
2675 | /* complete all the flushers sharing the current flush color */ | |
2676 | list_for_each_entry_safe(next, tmp, &wq->flusher_queue, list) { | |
2677 | if (next->flush_color != wq->flush_color) | |
2678 | break; | |
2679 | list_del_init(&next->list); | |
2680 | complete(&next->done); | |
2681 | } | |
2682 | ||
2683 | BUG_ON(!list_empty(&wq->flusher_overflow) && | |
2684 | wq->flush_color != work_next_color(wq->work_color)); | |
2685 | ||
2686 | /* this flush_color is finished, advance by one */ | |
2687 | wq->flush_color = work_next_color(wq->flush_color); | |
2688 | ||
2689 | /* one color has been freed, handle overflow queue */ | |
2690 | if (!list_empty(&wq->flusher_overflow)) { | |
2691 | /* | |
2692 | * Assign the same color to all overflowed | |
2693 | * flushers, advance work_color and append to | |
2694 | * flusher_queue. This is the start-to-wait | |
2695 | * phase for these overflowed flushers. | |
2696 | */ | |
2697 | list_for_each_entry(tmp, &wq->flusher_overflow, list) | |
2698 | tmp->flush_color = wq->work_color; | |
2699 | ||
2700 | wq->work_color = work_next_color(wq->work_color); | |
2701 | ||
2702 | list_splice_tail_init(&wq->flusher_overflow, | |
2703 | &wq->flusher_queue); | |
2704 | flush_workqueue_prep_cwqs(wq, -1, wq->work_color); | |
2705 | } | |
2706 | ||
2707 | if (list_empty(&wq->flusher_queue)) { | |
2708 | BUG_ON(wq->flush_color != wq->work_color); | |
2709 | break; | |
2710 | } | |
2711 | ||
2712 | /* | |
2713 | * Need to flush more colors. Make the next flusher | |
2714 | * the new first flusher and arm cwqs. | |
2715 | */ | |
2716 | BUG_ON(wq->flush_color == wq->work_color); | |
2717 | BUG_ON(wq->flush_color != next->flush_color); | |
2718 | ||
2719 | list_del_init(&next->list); | |
2720 | wq->first_flusher = next; | |
2721 | ||
2722 | if (flush_workqueue_prep_cwqs(wq, wq->flush_color, -1)) | |
2723 | break; | |
2724 | ||
2725 | /* | |
2726 | * Meh... this color is already done, clear first | |
2727 | * flusher and repeat cascading. | |
2728 | */ | |
2729 | wq->first_flusher = NULL; | |
2730 | } | |
2731 | ||
2732 | out_unlock: | |
2733 | mutex_unlock(&wq->flush_mutex); | |
1da177e4 | 2734 | } |
ae90dd5d | 2735 | EXPORT_SYMBOL_GPL(flush_workqueue); |
1da177e4 | 2736 | |
9c5a2ba7 TH |
2737 | /** |
2738 | * drain_workqueue - drain a workqueue | |
2739 | * @wq: workqueue to drain | |
2740 | * | |
2741 | * Wait until the workqueue becomes empty. While draining is in progress, | |
2742 | * only chain queueing is allowed. IOW, only currently pending or running | |
2743 | * work items on @wq can queue further work items on it. @wq is flushed | |
2744 | * repeatedly until it becomes empty. The number of flushing is detemined | |
2745 | * by the depth of chaining and should be relatively short. Whine if it | |
2746 | * takes too long. | |
2747 | */ | |
2748 | void drain_workqueue(struct workqueue_struct *wq) | |
2749 | { | |
2750 | unsigned int flush_cnt = 0; | |
2751 | unsigned int cpu; | |
2752 | ||
2753 | /* | |
2754 | * __queue_work() needs to test whether there are drainers, is much | |
2755 | * hotter than drain_workqueue() and already looks at @wq->flags. | |
2756 | * Use WQ_DRAINING so that queue doesn't have to check nr_drainers. | |
2757 | */ | |
2758 | spin_lock(&workqueue_lock); | |
2759 | if (!wq->nr_drainers++) | |
2760 | wq->flags |= WQ_DRAINING; | |
2761 | spin_unlock(&workqueue_lock); | |
2762 | reflush: | |
2763 | flush_workqueue(wq); | |
2764 | ||
2765 | for_each_cwq_cpu(cpu, wq) { | |
2766 | struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); | |
fa2563e4 | 2767 | bool drained; |
9c5a2ba7 | 2768 | |
d565ed63 | 2769 | spin_lock_irq(&cwq->pool->lock); |
fa2563e4 | 2770 | drained = !cwq->nr_active && list_empty(&cwq->delayed_works); |
d565ed63 | 2771 | spin_unlock_irq(&cwq->pool->lock); |
fa2563e4 TT |
2772 | |
2773 | if (drained) | |
9c5a2ba7 TH |
2774 | continue; |
2775 | ||
2776 | if (++flush_cnt == 10 || | |
2777 | (flush_cnt % 100 == 0 && flush_cnt <= 1000)) | |
044c782c VI |
2778 | pr_warn("workqueue %s: flush on destruction isn't complete after %u tries\n", |
2779 | wq->name, flush_cnt); | |
9c5a2ba7 TH |
2780 | goto reflush; |
2781 | } | |
2782 | ||
2783 | spin_lock(&workqueue_lock); | |
2784 | if (!--wq->nr_drainers) | |
2785 | wq->flags &= ~WQ_DRAINING; | |
2786 | spin_unlock(&workqueue_lock); | |
2787 | } | |
2788 | EXPORT_SYMBOL_GPL(drain_workqueue); | |
2789 | ||
606a5020 | 2790 | static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr) |
db700897 | 2791 | { |
affee4b2 | 2792 | struct worker *worker = NULL; |
c9e7cf27 | 2793 | struct worker_pool *pool; |
db700897 | 2794 | struct cpu_workqueue_struct *cwq; |
db700897 ON |
2795 | |
2796 | might_sleep(); | |
c9e7cf27 TH |
2797 | pool = get_work_pool(work); |
2798 | if (!pool) | |
baf59022 | 2799 | return false; |
db700897 | 2800 | |
d565ed63 | 2801 | spin_lock_irq(&pool->lock); |
db700897 ON |
2802 | if (!list_empty(&work->entry)) { |
2803 | /* | |
2804 | * See the comment near try_to_grab_pending()->smp_rmb(). | |
d565ed63 | 2805 | * If it was re-queued to a different pool under us, we |
7a22ad75 | 2806 | * are not going to wait. |
db700897 ON |
2807 | */ |
2808 | smp_rmb(); | |
7a22ad75 | 2809 | cwq = get_work_cwq(work); |
d565ed63 | 2810 | if (unlikely(!cwq || pool != cwq->pool)) |
4690c4ab | 2811 | goto already_gone; |
606a5020 | 2812 | } else { |
c9e7cf27 | 2813 | worker = find_worker_executing_work(pool, work); |
affee4b2 | 2814 | if (!worker) |
4690c4ab | 2815 | goto already_gone; |
7a22ad75 | 2816 | cwq = worker->current_cwq; |
606a5020 | 2817 | } |
db700897 | 2818 | |
baf59022 | 2819 | insert_wq_barrier(cwq, barr, work, worker); |
d565ed63 | 2820 | spin_unlock_irq(&pool->lock); |
7a22ad75 | 2821 | |
e159489b TH |
2822 | /* |
2823 | * If @max_active is 1 or rescuer is in use, flushing another work | |
2824 | * item on the same workqueue may lead to deadlock. Make sure the | |
2825 | * flusher is not running on the same workqueue by verifying write | |
2826 | * access. | |
2827 | */ | |
2828 | if (cwq->wq->saved_max_active == 1 || cwq->wq->flags & WQ_RESCUER) | |
2829 | lock_map_acquire(&cwq->wq->lockdep_map); | |
2830 | else | |
2831 | lock_map_acquire_read(&cwq->wq->lockdep_map); | |
7a22ad75 | 2832 | lock_map_release(&cwq->wq->lockdep_map); |
e159489b | 2833 | |
401a8d04 | 2834 | return true; |
4690c4ab | 2835 | already_gone: |
d565ed63 | 2836 | spin_unlock_irq(&pool->lock); |
401a8d04 | 2837 | return false; |
db700897 | 2838 | } |
baf59022 TH |
2839 | |
2840 | /** | |
2841 | * flush_work - wait for a work to finish executing the last queueing instance | |
2842 | * @work: the work to flush | |
2843 | * | |
606a5020 TH |
2844 | * Wait until @work has finished execution. @work is guaranteed to be idle |
2845 | * on return if it hasn't been requeued since flush started. | |
baf59022 TH |
2846 | * |
2847 | * RETURNS: | |
2848 | * %true if flush_work() waited for the work to finish execution, | |
2849 | * %false if it was already idle. | |
2850 | */ | |
2851 | bool flush_work(struct work_struct *work) | |
2852 | { | |
2853 | struct wq_barrier barr; | |
2854 | ||
0976dfc1 SB |
2855 | lock_map_acquire(&work->lockdep_map); |
2856 | lock_map_release(&work->lockdep_map); | |
2857 | ||
606a5020 | 2858 | if (start_flush_work(work, &barr)) { |
401a8d04 TH |
2859 | wait_for_completion(&barr.done); |
2860 | destroy_work_on_stack(&barr.work); | |
2861 | return true; | |
606a5020 | 2862 | } else { |
401a8d04 | 2863 | return false; |
6e84d644 | 2864 | } |
6e84d644 | 2865 | } |
606a5020 | 2866 | EXPORT_SYMBOL_GPL(flush_work); |
6e84d644 | 2867 | |
36e227d2 | 2868 | static bool __cancel_work_timer(struct work_struct *work, bool is_dwork) |
1f1f642e | 2869 | { |
bbb68dfa | 2870 | unsigned long flags; |
1f1f642e ON |
2871 | int ret; |
2872 | ||
2873 | do { | |
bbb68dfa TH |
2874 | ret = try_to_grab_pending(work, is_dwork, &flags); |
2875 | /* | |
2876 | * If someone else is canceling, wait for the same event it | |
2877 | * would be waiting for before retrying. | |
2878 | */ | |
2879 | if (unlikely(ret == -ENOENT)) | |
606a5020 | 2880 | flush_work(work); |
1f1f642e ON |
2881 | } while (unlikely(ret < 0)); |
2882 | ||
bbb68dfa TH |
2883 | /* tell other tasks trying to grab @work to back off */ |
2884 | mark_work_canceling(work); | |
2885 | local_irq_restore(flags); | |
2886 | ||
606a5020 | 2887 | flush_work(work); |
7a22ad75 | 2888 | clear_work_data(work); |
1f1f642e ON |
2889 | return ret; |
2890 | } | |
2891 | ||
6e84d644 | 2892 | /** |
401a8d04 TH |
2893 | * cancel_work_sync - cancel a work and wait for it to finish |
2894 | * @work: the work to cancel | |
6e84d644 | 2895 | * |
401a8d04 TH |
2896 | * Cancel @work and wait for its execution to finish. This function |
2897 | * can be used even if the work re-queues itself or migrates to | |
2898 | * another workqueue. On return from this function, @work is | |
2899 | * guaranteed to be not pending or executing on any CPU. | |
1f1f642e | 2900 | * |
401a8d04 TH |
2901 | * cancel_work_sync(&delayed_work->work) must not be used for |
2902 | * delayed_work's. Use cancel_delayed_work_sync() instead. | |
6e84d644 | 2903 | * |
401a8d04 | 2904 | * The caller must ensure that the workqueue on which @work was last |
6e84d644 | 2905 | * queued can't be destroyed before this function returns. |
401a8d04 TH |
2906 | * |
2907 | * RETURNS: | |
2908 | * %true if @work was pending, %false otherwise. | |
6e84d644 | 2909 | */ |
401a8d04 | 2910 | bool cancel_work_sync(struct work_struct *work) |
6e84d644 | 2911 | { |
36e227d2 | 2912 | return __cancel_work_timer(work, false); |
b89deed3 | 2913 | } |
28e53bdd | 2914 | EXPORT_SYMBOL_GPL(cancel_work_sync); |
b89deed3 | 2915 | |
6e84d644 | 2916 | /** |
401a8d04 TH |
2917 | * flush_delayed_work - wait for a dwork to finish executing the last queueing |
2918 | * @dwork: the delayed work to flush | |
6e84d644 | 2919 | * |
401a8d04 TH |
2920 | * Delayed timer is cancelled and the pending work is queued for |
2921 | * immediate execution. Like flush_work(), this function only | |
2922 | * considers the last queueing instance of @dwork. | |
1f1f642e | 2923 | * |
401a8d04 TH |
2924 | * RETURNS: |
2925 | * %true if flush_work() waited for the work to finish execution, | |
2926 | * %false if it was already idle. | |
6e84d644 | 2927 | */ |
401a8d04 TH |
2928 | bool flush_delayed_work(struct delayed_work *dwork) |
2929 | { | |
8930caba | 2930 | local_irq_disable(); |
401a8d04 | 2931 | if (del_timer_sync(&dwork->timer)) |
60c057bc | 2932 | __queue_work(dwork->cpu, dwork->wq, &dwork->work); |
8930caba | 2933 | local_irq_enable(); |
401a8d04 TH |
2934 | return flush_work(&dwork->work); |
2935 | } | |
2936 | EXPORT_SYMBOL(flush_delayed_work); | |
2937 | ||
09383498 | 2938 | /** |
57b30ae7 TH |
2939 | * cancel_delayed_work - cancel a delayed work |
2940 | * @dwork: delayed_work to cancel | |
09383498 | 2941 | * |
57b30ae7 TH |
2942 | * Kill off a pending delayed_work. Returns %true if @dwork was pending |
2943 | * and canceled; %false if wasn't pending. Note that the work callback | |
2944 | * function may still be running on return, unless it returns %true and the | |
2945 | * work doesn't re-arm itself. Explicitly flush or use | |
2946 | * cancel_delayed_work_sync() to wait on it. | |
09383498 | 2947 | * |
57b30ae7 | 2948 | * This function is safe to call from any context including IRQ handler. |
09383498 | 2949 | */ |
57b30ae7 | 2950 | bool cancel_delayed_work(struct delayed_work *dwork) |
09383498 | 2951 | { |
57b30ae7 TH |
2952 | unsigned long flags; |
2953 | int ret; | |
2954 | ||
2955 | do { | |
2956 | ret = try_to_grab_pending(&dwork->work, true, &flags); | |
2957 | } while (unlikely(ret == -EAGAIN)); | |
2958 | ||
2959 | if (unlikely(ret < 0)) | |
2960 | return false; | |
2961 | ||
7c3eed5c TH |
2962 | set_work_pool_and_clear_pending(&dwork->work, |
2963 | get_work_pool_id(&dwork->work)); | |
57b30ae7 | 2964 | local_irq_restore(flags); |
c0158ca6 | 2965 | return ret; |
09383498 | 2966 | } |
57b30ae7 | 2967 | EXPORT_SYMBOL(cancel_delayed_work); |
09383498 | 2968 | |
401a8d04 TH |
2969 | /** |
2970 | * cancel_delayed_work_sync - cancel a delayed work and wait for it to finish | |
2971 | * @dwork: the delayed work cancel | |
2972 | * | |
2973 | * This is cancel_work_sync() for delayed works. | |
2974 | * | |
2975 | * RETURNS: | |
2976 | * %true if @dwork was pending, %false otherwise. | |
2977 | */ | |
2978 | bool cancel_delayed_work_sync(struct delayed_work *dwork) | |
6e84d644 | 2979 | { |
36e227d2 | 2980 | return __cancel_work_timer(&dwork->work, true); |
6e84d644 | 2981 | } |
f5a421a4 | 2982 | EXPORT_SYMBOL(cancel_delayed_work_sync); |
1da177e4 | 2983 | |
0fcb78c2 | 2984 | /** |
c1a220e7 ZR |
2985 | * schedule_work_on - put work task on a specific cpu |
2986 | * @cpu: cpu to put the work task on | |
2987 | * @work: job to be done | |
2988 | * | |
2989 | * This puts a job on a specific cpu | |
2990 | */ | |
d4283e93 | 2991 | bool schedule_work_on(int cpu, struct work_struct *work) |
c1a220e7 | 2992 | { |
d320c038 | 2993 | return queue_work_on(cpu, system_wq, work); |
c1a220e7 ZR |
2994 | } |
2995 | EXPORT_SYMBOL(schedule_work_on); | |
2996 | ||
0fcb78c2 | 2997 | /** |
0fcb78c2 REB |
2998 | * schedule_work - put work task in global workqueue |
2999 | * @work: job to be done | |
0fcb78c2 | 3000 | * |
d4283e93 TH |
3001 | * Returns %false if @work was already on the kernel-global workqueue and |
3002 | * %true otherwise. | |
5b0f437d BVA |
3003 | * |
3004 | * This puts a job in the kernel-global workqueue if it was not already | |
3005 | * queued and leaves it in the same position on the kernel-global | |
3006 | * workqueue otherwise. | |
0fcb78c2 | 3007 | */ |
d4283e93 | 3008 | bool schedule_work(struct work_struct *work) |
1da177e4 | 3009 | { |
d320c038 | 3010 | return queue_work(system_wq, work); |
1da177e4 | 3011 | } |
ae90dd5d | 3012 | EXPORT_SYMBOL(schedule_work); |
1da177e4 | 3013 | |
0fcb78c2 REB |
3014 | /** |
3015 | * schedule_delayed_work_on - queue work in global workqueue on CPU after delay | |
3016 | * @cpu: cpu to use | |
52bad64d | 3017 | * @dwork: job to be done |
0fcb78c2 REB |
3018 | * @delay: number of jiffies to wait |
3019 | * | |
3020 | * After waiting for a given time this puts a job in the kernel-global | |
3021 | * workqueue on the specified CPU. | |
3022 | */ | |
d4283e93 TH |
3023 | bool schedule_delayed_work_on(int cpu, struct delayed_work *dwork, |
3024 | unsigned long delay) | |
1da177e4 | 3025 | { |
d320c038 | 3026 | return queue_delayed_work_on(cpu, system_wq, dwork, delay); |
1da177e4 | 3027 | } |
ae90dd5d | 3028 | EXPORT_SYMBOL(schedule_delayed_work_on); |
1da177e4 | 3029 | |
0fcb78c2 REB |
3030 | /** |
3031 | * schedule_delayed_work - put work task in global workqueue after delay | |
52bad64d DH |
3032 | * @dwork: job to be done |
3033 | * @delay: number of jiffies to wait or 0 for immediate execution | |
0fcb78c2 REB |
3034 | * |
3035 | * After waiting for a given time this puts a job in the kernel-global | |
3036 | * workqueue. | |
3037 | */ | |
d4283e93 | 3038 | bool schedule_delayed_work(struct delayed_work *dwork, unsigned long delay) |
1da177e4 | 3039 | { |
d320c038 | 3040 | return queue_delayed_work(system_wq, dwork, delay); |
1da177e4 | 3041 | } |
ae90dd5d | 3042 | EXPORT_SYMBOL(schedule_delayed_work); |
1da177e4 | 3043 | |
b6136773 | 3044 | /** |
31ddd871 | 3045 | * schedule_on_each_cpu - execute a function synchronously on each online CPU |
b6136773 | 3046 | * @func: the function to call |
b6136773 | 3047 | * |
31ddd871 TH |
3048 | * schedule_on_each_cpu() executes @func on each online CPU using the |
3049 | * system workqueue and blocks until all CPUs have completed. | |
b6136773 | 3050 | * schedule_on_each_cpu() is very slow. |
31ddd871 TH |
3051 | * |
3052 | * RETURNS: | |
3053 | * 0 on success, -errno on failure. | |
b6136773 | 3054 | */ |
65f27f38 | 3055 | int schedule_on_each_cpu(work_func_t func) |
15316ba8 CL |
3056 | { |
3057 | int cpu; | |
38f51568 | 3058 | struct work_struct __percpu *works; |
15316ba8 | 3059 | |
b6136773 AM |
3060 | works = alloc_percpu(struct work_struct); |
3061 | if (!works) | |
15316ba8 | 3062 | return -ENOMEM; |
b6136773 | 3063 | |
93981800 TH |
3064 | get_online_cpus(); |
3065 | ||
15316ba8 | 3066 | for_each_online_cpu(cpu) { |
9bfb1839 IM |
3067 | struct work_struct *work = per_cpu_ptr(works, cpu); |
3068 | ||
3069 | INIT_WORK(work, func); | |
b71ab8c2 | 3070 | schedule_work_on(cpu, work); |
65a64464 | 3071 | } |
93981800 TH |
3072 | |
3073 | for_each_online_cpu(cpu) | |
3074 | flush_work(per_cpu_ptr(works, cpu)); | |
3075 | ||
95402b38 | 3076 | put_online_cpus(); |
b6136773 | 3077 | free_percpu(works); |
15316ba8 CL |
3078 | return 0; |
3079 | } | |
3080 | ||
eef6a7d5 AS |
3081 | /** |
3082 | * flush_scheduled_work - ensure that any scheduled work has run to completion. | |
3083 | * | |
3084 | * Forces execution of the kernel-global workqueue and blocks until its | |
3085 | * completion. | |
3086 | * | |
3087 | * Think twice before calling this function! It's very easy to get into | |
3088 | * trouble if you don't take great care. Either of the following situations | |
3089 | * will lead to deadlock: | |
3090 | * | |
3091 | * One of the work items currently on the workqueue needs to acquire | |
3092 | * a lock held by your code or its caller. | |
3093 | * | |
3094 | * Your code is running in the context of a work routine. | |
3095 | * | |
3096 | * They will be detected by lockdep when they occur, but the first might not | |
3097 | * occur very often. It depends on what work items are on the workqueue and | |
3098 | * what locks they need, which you have no control over. | |
3099 | * | |
3100 | * In most situations flushing the entire workqueue is overkill; you merely | |
3101 | * need to know that a particular work item isn't queued and isn't running. | |
3102 | * In such cases you should use cancel_delayed_work_sync() or | |
3103 | * cancel_work_sync() instead. | |
3104 | */ | |
1da177e4 LT |
3105 | void flush_scheduled_work(void) |
3106 | { | |
d320c038 | 3107 | flush_workqueue(system_wq); |
1da177e4 | 3108 | } |
ae90dd5d | 3109 | EXPORT_SYMBOL(flush_scheduled_work); |
1da177e4 | 3110 | |
1fa44eca JB |
3111 | /** |
3112 | * execute_in_process_context - reliably execute the routine with user context | |
3113 | * @fn: the function to execute | |
1fa44eca JB |
3114 | * @ew: guaranteed storage for the execute work structure (must |
3115 | * be available when the work executes) | |
3116 | * | |
3117 | * Executes the function immediately if process context is available, | |
3118 | * otherwise schedules the function for delayed execution. | |
3119 | * | |
3120 | * Returns: 0 - function was executed | |
3121 | * 1 - function was scheduled for execution | |
3122 | */ | |
65f27f38 | 3123 | int execute_in_process_context(work_func_t fn, struct execute_work *ew) |
1fa44eca JB |
3124 | { |
3125 | if (!in_interrupt()) { | |
65f27f38 | 3126 | fn(&ew->work); |
1fa44eca JB |
3127 | return 0; |
3128 | } | |
3129 | ||
65f27f38 | 3130 | INIT_WORK(&ew->work, fn); |
1fa44eca JB |
3131 | schedule_work(&ew->work); |
3132 | ||
3133 | return 1; | |
3134 | } | |
3135 | EXPORT_SYMBOL_GPL(execute_in_process_context); | |
3136 | ||
1da177e4 LT |
3137 | int keventd_up(void) |
3138 | { | |
d320c038 | 3139 | return system_wq != NULL; |
1da177e4 LT |
3140 | } |
3141 | ||
bdbc5dd7 | 3142 | static int alloc_cwqs(struct workqueue_struct *wq) |
0f900049 | 3143 | { |
65a64464 | 3144 | /* |
0f900049 TH |
3145 | * cwqs are forced aligned according to WORK_STRUCT_FLAG_BITS. |
3146 | * Make sure that the alignment isn't lower than that of | |
3147 | * unsigned long long. | |
65a64464 | 3148 | */ |
0f900049 TH |
3149 | const size_t size = sizeof(struct cpu_workqueue_struct); |
3150 | const size_t align = max_t(size_t, 1 << WORK_STRUCT_FLAG_BITS, | |
3151 | __alignof__(unsigned long long)); | |
65a64464 | 3152 | |
e06ffa1e | 3153 | if (!(wq->flags & WQ_UNBOUND)) |
f3421797 | 3154 | wq->cpu_wq.pcpu = __alloc_percpu(size, align); |
931ac77e | 3155 | else { |
f3421797 TH |
3156 | void *ptr; |
3157 | ||
3158 | /* | |
3159 | * Allocate enough room to align cwq and put an extra | |
3160 | * pointer at the end pointing back to the originally | |
3161 | * allocated pointer which will be used for free. | |
3162 | */ | |
3163 | ptr = kzalloc(size + align + sizeof(void *), GFP_KERNEL); | |
3164 | if (ptr) { | |
3165 | wq->cpu_wq.single = PTR_ALIGN(ptr, align); | |
3166 | *(void **)(wq->cpu_wq.single + 1) = ptr; | |
3167 | } | |
bdbc5dd7 | 3168 | } |
f3421797 | 3169 | |
0415b00d | 3170 | /* just in case, make sure it's actually aligned */ |
bdbc5dd7 TH |
3171 | BUG_ON(!IS_ALIGNED(wq->cpu_wq.v, align)); |
3172 | return wq->cpu_wq.v ? 0 : -ENOMEM; | |
0f900049 TH |
3173 | } |
3174 | ||
bdbc5dd7 | 3175 | static void free_cwqs(struct workqueue_struct *wq) |
0f900049 | 3176 | { |
e06ffa1e | 3177 | if (!(wq->flags & WQ_UNBOUND)) |
f3421797 TH |
3178 | free_percpu(wq->cpu_wq.pcpu); |
3179 | else if (wq->cpu_wq.single) { | |
3180 | /* the pointer to free is stored right after the cwq */ | |
bdbc5dd7 | 3181 | kfree(*(void **)(wq->cpu_wq.single + 1)); |
f3421797 | 3182 | } |
0f900049 TH |
3183 | } |
3184 | ||
f3421797 TH |
3185 | static int wq_clamp_max_active(int max_active, unsigned int flags, |
3186 | const char *name) | |
b71ab8c2 | 3187 | { |
f3421797 TH |
3188 | int lim = flags & WQ_UNBOUND ? WQ_UNBOUND_MAX_ACTIVE : WQ_MAX_ACTIVE; |
3189 | ||
3190 | if (max_active < 1 || max_active > lim) | |
044c782c VI |
3191 | pr_warn("workqueue: max_active %d requested for %s is out of range, clamping between %d and %d\n", |
3192 | max_active, name, 1, lim); | |
b71ab8c2 | 3193 | |
f3421797 | 3194 | return clamp_val(max_active, 1, lim); |
b71ab8c2 TH |
3195 | } |
3196 | ||
b196be89 | 3197 | struct workqueue_struct *__alloc_workqueue_key(const char *fmt, |
d320c038 TH |
3198 | unsigned int flags, |
3199 | int max_active, | |
3200 | struct lock_class_key *key, | |
b196be89 | 3201 | const char *lock_name, ...) |
1da177e4 | 3202 | { |
b196be89 | 3203 | va_list args, args1; |
1da177e4 | 3204 | struct workqueue_struct *wq; |
c34056a3 | 3205 | unsigned int cpu; |
b196be89 TH |
3206 | size_t namelen; |
3207 | ||
3208 | /* determine namelen, allocate wq and format name */ | |
3209 | va_start(args, lock_name); | |
3210 | va_copy(args1, args); | |
3211 | namelen = vsnprintf(NULL, 0, fmt, args) + 1; | |
3212 | ||
3213 | wq = kzalloc(sizeof(*wq) + namelen, GFP_KERNEL); | |
3214 | if (!wq) | |
3215 | goto err; | |
3216 | ||
3217 | vsnprintf(wq->name, namelen, fmt, args1); | |
3218 | va_end(args); | |
3219 | va_end(args1); | |
1da177e4 | 3220 | |
6370a6ad TH |
3221 | /* |
3222 | * Workqueues which may be used during memory reclaim should | |
3223 | * have a rescuer to guarantee forward progress. | |
3224 | */ | |
3225 | if (flags & WQ_MEM_RECLAIM) | |
3226 | flags |= WQ_RESCUER; | |
3227 | ||
d320c038 | 3228 | max_active = max_active ?: WQ_DFL_ACTIVE; |
b196be89 | 3229 | max_active = wq_clamp_max_active(max_active, flags, wq->name); |
3af24433 | 3230 | |
b196be89 | 3231 | /* init wq */ |
97e37d7b | 3232 | wq->flags = flags; |
a0a1a5fd | 3233 | wq->saved_max_active = max_active; |
73f53c4a TH |
3234 | mutex_init(&wq->flush_mutex); |
3235 | atomic_set(&wq->nr_cwqs_to_flush, 0); | |
3236 | INIT_LIST_HEAD(&wq->flusher_queue); | |
3237 | INIT_LIST_HEAD(&wq->flusher_overflow); | |
502ca9d8 | 3238 | |
eb13ba87 | 3239 | lockdep_init_map(&wq->lockdep_map, lock_name, key, 0); |
cce1a165 | 3240 | INIT_LIST_HEAD(&wq->list); |
3af24433 | 3241 | |
bdbc5dd7 TH |
3242 | if (alloc_cwqs(wq) < 0) |
3243 | goto err; | |
3244 | ||
f3421797 | 3245 | for_each_cwq_cpu(cpu, wq) { |
1537663f TH |
3246 | struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); |
3247 | ||
0f900049 | 3248 | BUG_ON((unsigned long)cwq & WORK_STRUCT_FLAG_MASK); |
a60dc39c | 3249 | cwq->pool = get_std_worker_pool(cpu, flags & WQ_HIGHPRI); |
c34056a3 | 3250 | cwq->wq = wq; |
73f53c4a | 3251 | cwq->flush_color = -1; |
1e19ffc6 | 3252 | cwq->max_active = max_active; |
1e19ffc6 | 3253 | INIT_LIST_HEAD(&cwq->delayed_works); |
e22bee78 | 3254 | } |
1537663f | 3255 | |
e22bee78 TH |
3256 | if (flags & WQ_RESCUER) { |
3257 | struct worker *rescuer; | |
3258 | ||
f2e005aa | 3259 | if (!alloc_mayday_mask(&wq->mayday_mask, GFP_KERNEL)) |
e22bee78 TH |
3260 | goto err; |
3261 | ||
3262 | wq->rescuer = rescuer = alloc_worker(); | |
3263 | if (!rescuer) | |
3264 | goto err; | |
3265 | ||
111c225a TH |
3266 | rescuer->rescue_wq = wq; |
3267 | rescuer->task = kthread_create(rescuer_thread, rescuer, "%s", | |
b196be89 | 3268 | wq->name); |
e22bee78 TH |
3269 | if (IS_ERR(rescuer->task)) |
3270 | goto err; | |
3271 | ||
e22bee78 TH |
3272 | rescuer->task->flags |= PF_THREAD_BOUND; |
3273 | wake_up_process(rescuer->task); | |
3af24433 ON |
3274 | } |
3275 | ||
a0a1a5fd TH |
3276 | /* |
3277 | * workqueue_lock protects global freeze state and workqueues | |
3278 | * list. Grab it, set max_active accordingly and add the new | |
3279 | * workqueue to workqueues list. | |
3280 | */ | |
1537663f | 3281 | spin_lock(&workqueue_lock); |
a0a1a5fd | 3282 | |
58a69cb4 | 3283 | if (workqueue_freezing && wq->flags & WQ_FREEZABLE) |
f3421797 | 3284 | for_each_cwq_cpu(cpu, wq) |
a0a1a5fd TH |
3285 | get_cwq(cpu, wq)->max_active = 0; |
3286 | ||
1537663f | 3287 | list_add(&wq->list, &workqueues); |
a0a1a5fd | 3288 | |
1537663f TH |
3289 | spin_unlock(&workqueue_lock); |
3290 | ||
3af24433 | 3291 | return wq; |
4690c4ab TH |
3292 | err: |
3293 | if (wq) { | |
bdbc5dd7 | 3294 | free_cwqs(wq); |
f2e005aa | 3295 | free_mayday_mask(wq->mayday_mask); |
e22bee78 | 3296 | kfree(wq->rescuer); |
4690c4ab TH |
3297 | kfree(wq); |
3298 | } | |
3299 | return NULL; | |
3af24433 | 3300 | } |
d320c038 | 3301 | EXPORT_SYMBOL_GPL(__alloc_workqueue_key); |
1da177e4 | 3302 | |
3af24433 ON |
3303 | /** |
3304 | * destroy_workqueue - safely terminate a workqueue | |
3305 | * @wq: target workqueue | |
3306 | * | |
3307 | * Safely destroy a workqueue. All work currently pending will be done first. | |
3308 | */ | |
3309 | void destroy_workqueue(struct workqueue_struct *wq) | |
3310 | { | |
c8e55f36 | 3311 | unsigned int cpu; |
3af24433 | 3312 | |
9c5a2ba7 TH |
3313 | /* drain it before proceeding with destruction */ |
3314 | drain_workqueue(wq); | |
c8efcc25 | 3315 | |
a0a1a5fd TH |
3316 | /* |
3317 | * wq list is used to freeze wq, remove from list after | |
3318 | * flushing is complete in case freeze races us. | |
3319 | */ | |
95402b38 | 3320 | spin_lock(&workqueue_lock); |
b1f4ec17 | 3321 | list_del(&wq->list); |
95402b38 | 3322 | spin_unlock(&workqueue_lock); |
3af24433 | 3323 | |
e22bee78 | 3324 | /* sanity check */ |
f3421797 | 3325 | for_each_cwq_cpu(cpu, wq) { |
73f53c4a TH |
3326 | struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); |
3327 | int i; | |
3328 | ||
73f53c4a TH |
3329 | for (i = 0; i < WORK_NR_COLORS; i++) |
3330 | BUG_ON(cwq->nr_in_flight[i]); | |
1e19ffc6 TH |
3331 | BUG_ON(cwq->nr_active); |
3332 | BUG_ON(!list_empty(&cwq->delayed_works)); | |
73f53c4a | 3333 | } |
9b41ea72 | 3334 | |
e22bee78 TH |
3335 | if (wq->flags & WQ_RESCUER) { |
3336 | kthread_stop(wq->rescuer->task); | |
f2e005aa | 3337 | free_mayday_mask(wq->mayday_mask); |
8d9df9f0 | 3338 | kfree(wq->rescuer); |
e22bee78 TH |
3339 | } |
3340 | ||
bdbc5dd7 | 3341 | free_cwqs(wq); |
3af24433 ON |
3342 | kfree(wq); |
3343 | } | |
3344 | EXPORT_SYMBOL_GPL(destroy_workqueue); | |
3345 | ||
9f4bd4cd LJ |
3346 | /** |
3347 | * cwq_set_max_active - adjust max_active of a cwq | |
3348 | * @cwq: target cpu_workqueue_struct | |
3349 | * @max_active: new max_active value. | |
3350 | * | |
3351 | * Set @cwq->max_active to @max_active and activate delayed works if | |
3352 | * increased. | |
3353 | * | |
3354 | * CONTEXT: | |
d565ed63 | 3355 | * spin_lock_irq(pool->lock). |
9f4bd4cd LJ |
3356 | */ |
3357 | static void cwq_set_max_active(struct cpu_workqueue_struct *cwq, int max_active) | |
3358 | { | |
3359 | cwq->max_active = max_active; | |
3360 | ||
3361 | while (!list_empty(&cwq->delayed_works) && | |
3362 | cwq->nr_active < cwq->max_active) | |
3363 | cwq_activate_first_delayed(cwq); | |
3364 | } | |
3365 | ||
dcd989cb TH |
3366 | /** |
3367 | * workqueue_set_max_active - adjust max_active of a workqueue | |
3368 | * @wq: target workqueue | |
3369 | * @max_active: new max_active value. | |
3370 | * | |
3371 | * Set max_active of @wq to @max_active. | |
3372 | * | |
3373 | * CONTEXT: | |
3374 | * Don't call from IRQ context. | |
3375 | */ | |
3376 | void workqueue_set_max_active(struct workqueue_struct *wq, int max_active) | |
3377 | { | |
3378 | unsigned int cpu; | |
3379 | ||
f3421797 | 3380 | max_active = wq_clamp_max_active(max_active, wq->flags, wq->name); |
dcd989cb TH |
3381 | |
3382 | spin_lock(&workqueue_lock); | |
3383 | ||
3384 | wq->saved_max_active = max_active; | |
3385 | ||
f3421797 | 3386 | for_each_cwq_cpu(cpu, wq) { |
35b6bb63 TH |
3387 | struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); |
3388 | struct worker_pool *pool = cwq->pool; | |
dcd989cb | 3389 | |
d565ed63 | 3390 | spin_lock_irq(&pool->lock); |
dcd989cb | 3391 | |
58a69cb4 | 3392 | if (!(wq->flags & WQ_FREEZABLE) || |
35b6bb63 TH |
3393 | !(pool->flags & POOL_FREEZING)) |
3394 | cwq_set_max_active(cwq, max_active); | |
9bfb1839 | 3395 | |
d565ed63 | 3396 | spin_unlock_irq(&pool->lock); |
65a64464 | 3397 | } |
93981800 | 3398 | |
dcd989cb | 3399 | spin_unlock(&workqueue_lock); |
15316ba8 | 3400 | } |
dcd989cb | 3401 | EXPORT_SYMBOL_GPL(workqueue_set_max_active); |
15316ba8 | 3402 | |
eef6a7d5 | 3403 | /** |
dcd989cb TH |
3404 | * workqueue_congested - test whether a workqueue is congested |
3405 | * @cpu: CPU in question | |
3406 | * @wq: target workqueue | |
eef6a7d5 | 3407 | * |
dcd989cb TH |
3408 | * Test whether @wq's cpu workqueue for @cpu is congested. There is |
3409 | * no synchronization around this function and the test result is | |
3410 | * unreliable and only useful as advisory hints or for debugging. | |
eef6a7d5 | 3411 | * |
dcd989cb TH |
3412 | * RETURNS: |
3413 | * %true if congested, %false otherwise. | |
eef6a7d5 | 3414 | */ |
dcd989cb | 3415 | bool workqueue_congested(unsigned int cpu, struct workqueue_struct *wq) |
1da177e4 | 3416 | { |
dcd989cb TH |
3417 | struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); |
3418 | ||
3419 | return !list_empty(&cwq->delayed_works); | |
1da177e4 | 3420 | } |
dcd989cb | 3421 | EXPORT_SYMBOL_GPL(workqueue_congested); |
1da177e4 | 3422 | |
dcd989cb TH |
3423 | /** |
3424 | * work_busy - test whether a work is currently pending or running | |
3425 | * @work: the work to be tested | |
3426 | * | |
3427 | * Test whether @work is currently pending or running. There is no | |
3428 | * synchronization around this function and the test result is | |
3429 | * unreliable and only useful as advisory hints or for debugging. | |
dcd989cb TH |
3430 | * |
3431 | * RETURNS: | |
3432 | * OR'd bitmask of WORK_BUSY_* bits. | |
3433 | */ | |
3434 | unsigned int work_busy(struct work_struct *work) | |
1da177e4 | 3435 | { |
c9e7cf27 | 3436 | struct worker_pool *pool = get_work_pool(work); |
dcd989cb TH |
3437 | unsigned long flags; |
3438 | unsigned int ret = 0; | |
1da177e4 | 3439 | |
dcd989cb TH |
3440 | if (work_pending(work)) |
3441 | ret |= WORK_BUSY_PENDING; | |
1da177e4 | 3442 | |
038366c5 LJ |
3443 | if (pool) { |
3444 | spin_lock_irqsave(&pool->lock, flags); | |
3445 | if (find_worker_executing_work(pool, work)) | |
3446 | ret |= WORK_BUSY_RUNNING; | |
3447 | spin_unlock_irqrestore(&pool->lock, flags); | |
3448 | } | |
1da177e4 | 3449 | |
dcd989cb | 3450 | return ret; |
1da177e4 | 3451 | } |
dcd989cb | 3452 | EXPORT_SYMBOL_GPL(work_busy); |
1da177e4 | 3453 | |
db7bccf4 TH |
3454 | /* |
3455 | * CPU hotplug. | |
3456 | * | |
e22bee78 TH |
3457 | * There are two challenges in supporting CPU hotplug. Firstly, there |
3458 | * are a lot of assumptions on strong associations among work, cwq and | |
706026c2 | 3459 | * pool which make migrating pending and scheduled works very |
e22bee78 | 3460 | * difficult to implement without impacting hot paths. Secondly, |
94cf58bb | 3461 | * worker pools serve mix of short, long and very long running works making |
e22bee78 TH |
3462 | * blocked draining impractical. |
3463 | * | |
24647570 | 3464 | * This is solved by allowing the pools to be disassociated from the CPU |
628c78e7 TH |
3465 | * running as an unbound one and allowing it to be reattached later if the |
3466 | * cpu comes back online. | |
db7bccf4 | 3467 | */ |
1da177e4 | 3468 | |
706026c2 | 3469 | static void wq_unbind_fn(struct work_struct *work) |
3af24433 | 3470 | { |
38db41d9 | 3471 | int cpu = smp_processor_id(); |
4ce62e9e | 3472 | struct worker_pool *pool; |
db7bccf4 TH |
3473 | struct worker *worker; |
3474 | struct hlist_node *pos; | |
3475 | int i; | |
3af24433 | 3476 | |
38db41d9 TH |
3477 | for_each_std_worker_pool(pool, cpu) { |
3478 | BUG_ON(cpu != smp_processor_id()); | |
db7bccf4 | 3479 | |
94cf58bb TH |
3480 | mutex_lock(&pool->assoc_mutex); |
3481 | spin_lock_irq(&pool->lock); | |
3af24433 | 3482 | |
94cf58bb TH |
3483 | /* |
3484 | * We've claimed all manager positions. Make all workers | |
3485 | * unbound and set DISASSOCIATED. Before this, all workers | |
3486 | * except for the ones which are still executing works from | |
3487 | * before the last CPU down must be on the cpu. After | |
3488 | * this, they may become diasporas. | |
3489 | */ | |
4ce62e9e | 3490 | list_for_each_entry(worker, &pool->idle_list, entry) |
403c821d | 3491 | worker->flags |= WORKER_UNBOUND; |
3af24433 | 3492 | |
c9e7cf27 TH |
3493 | for_each_busy_worker(worker, i, pos, pool) |
3494 | worker->flags |= WORKER_UNBOUND; | |
06ba38a9 | 3495 | |
24647570 | 3496 | pool->flags |= POOL_DISASSOCIATED; |
f2d5a0ee | 3497 | |
94cf58bb TH |
3498 | spin_unlock_irq(&pool->lock); |
3499 | mutex_unlock(&pool->assoc_mutex); | |
3500 | } | |
628c78e7 | 3501 | |
e22bee78 | 3502 | /* |
403c821d | 3503 | * Call schedule() so that we cross rq->lock and thus can guarantee |
628c78e7 TH |
3504 | * sched callbacks see the %WORKER_UNBOUND flag. This is necessary |
3505 | * as scheduler callbacks may be invoked from other cpus. | |
e22bee78 | 3506 | */ |
e22bee78 | 3507 | schedule(); |
06ba38a9 | 3508 | |
e22bee78 | 3509 | /* |
628c78e7 TH |
3510 | * Sched callbacks are disabled now. Zap nr_running. After this, |
3511 | * nr_running stays zero and need_more_worker() and keep_working() | |
38db41d9 TH |
3512 | * are always true as long as the worklist is not empty. Pools on |
3513 | * @cpu now behave as unbound (in terms of concurrency management) | |
3514 | * pools which are served by workers tied to the CPU. | |
628c78e7 TH |
3515 | * |
3516 | * On return from this function, the current worker would trigger | |
3517 | * unbound chain execution of pending work items if other workers | |
3518 | * didn't already. | |
e22bee78 | 3519 | */ |
38db41d9 | 3520 | for_each_std_worker_pool(pool, cpu) |
4ce62e9e | 3521 | atomic_set(get_pool_nr_running(pool), 0); |
3af24433 | 3522 | } |
3af24433 | 3523 | |
8db25e78 TH |
3524 | /* |
3525 | * Workqueues should be brought up before normal priority CPU notifiers. | |
3526 | * This will be registered high priority CPU notifier. | |
3527 | */ | |
9fdf9b73 | 3528 | static int __cpuinit workqueue_cpu_up_callback(struct notifier_block *nfb, |
8db25e78 TH |
3529 | unsigned long action, |
3530 | void *hcpu) | |
3af24433 ON |
3531 | { |
3532 | unsigned int cpu = (unsigned long)hcpu; | |
4ce62e9e | 3533 | struct worker_pool *pool; |
3ce63377 | 3534 | |
8db25e78 | 3535 | switch (action & ~CPU_TASKS_FROZEN) { |
3af24433 | 3536 | case CPU_UP_PREPARE: |
38db41d9 | 3537 | for_each_std_worker_pool(pool, cpu) { |
3ce63377 TH |
3538 | struct worker *worker; |
3539 | ||
3540 | if (pool->nr_workers) | |
3541 | continue; | |
3542 | ||
3543 | worker = create_worker(pool); | |
3544 | if (!worker) | |
3545 | return NOTIFY_BAD; | |
3546 | ||
d565ed63 | 3547 | spin_lock_irq(&pool->lock); |
3ce63377 | 3548 | start_worker(worker); |
d565ed63 | 3549 | spin_unlock_irq(&pool->lock); |
3af24433 | 3550 | } |
8db25e78 | 3551 | break; |
3af24433 | 3552 | |
db7bccf4 TH |
3553 | case CPU_DOWN_FAILED: |
3554 | case CPU_ONLINE: | |
38db41d9 | 3555 | for_each_std_worker_pool(pool, cpu) { |
94cf58bb TH |
3556 | mutex_lock(&pool->assoc_mutex); |
3557 | spin_lock_irq(&pool->lock); | |
3558 | ||
24647570 | 3559 | pool->flags &= ~POOL_DISASSOCIATED; |
94cf58bb TH |
3560 | rebind_workers(pool); |
3561 | ||
3562 | spin_unlock_irq(&pool->lock); | |
3563 | mutex_unlock(&pool->assoc_mutex); | |
3564 | } | |
db7bccf4 | 3565 | break; |
00dfcaf7 | 3566 | } |
65758202 TH |
3567 | return NOTIFY_OK; |
3568 | } | |
3569 | ||
3570 | /* | |
3571 | * Workqueues should be brought down after normal priority CPU notifiers. | |
3572 | * This will be registered as low priority CPU notifier. | |
3573 | */ | |
9fdf9b73 | 3574 | static int __cpuinit workqueue_cpu_down_callback(struct notifier_block *nfb, |
65758202 TH |
3575 | unsigned long action, |
3576 | void *hcpu) | |
3577 | { | |
8db25e78 TH |
3578 | unsigned int cpu = (unsigned long)hcpu; |
3579 | struct work_struct unbind_work; | |
3580 | ||
65758202 TH |
3581 | switch (action & ~CPU_TASKS_FROZEN) { |
3582 | case CPU_DOWN_PREPARE: | |
8db25e78 | 3583 | /* unbinding should happen on the local CPU */ |
706026c2 | 3584 | INIT_WORK_ONSTACK(&unbind_work, wq_unbind_fn); |
7635d2fd | 3585 | queue_work_on(cpu, system_highpri_wq, &unbind_work); |
8db25e78 TH |
3586 | flush_work(&unbind_work); |
3587 | break; | |
65758202 TH |
3588 | } |
3589 | return NOTIFY_OK; | |
3590 | } | |
3591 | ||
2d3854a3 | 3592 | #ifdef CONFIG_SMP |
8ccad40d | 3593 | |
2d3854a3 | 3594 | struct work_for_cpu { |
ed48ece2 | 3595 | struct work_struct work; |
2d3854a3 RR |
3596 | long (*fn)(void *); |
3597 | void *arg; | |
3598 | long ret; | |
3599 | }; | |
3600 | ||
ed48ece2 | 3601 | static void work_for_cpu_fn(struct work_struct *work) |
2d3854a3 | 3602 | { |
ed48ece2 TH |
3603 | struct work_for_cpu *wfc = container_of(work, struct work_for_cpu, work); |
3604 | ||
2d3854a3 RR |
3605 | wfc->ret = wfc->fn(wfc->arg); |
3606 | } | |
3607 | ||
3608 | /** | |
3609 | * work_on_cpu - run a function in user context on a particular cpu | |
3610 | * @cpu: the cpu to run on | |
3611 | * @fn: the function to run | |
3612 | * @arg: the function arg | |
3613 | * | |
31ad9081 RR |
3614 | * This will return the value @fn returns. |
3615 | * It is up to the caller to ensure that the cpu doesn't go offline. | |
6b44003e | 3616 | * The caller must not hold any locks which would prevent @fn from completing. |
2d3854a3 RR |
3617 | */ |
3618 | long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg) | |
3619 | { | |
ed48ece2 | 3620 | struct work_for_cpu wfc = { .fn = fn, .arg = arg }; |
6b44003e | 3621 | |
ed48ece2 TH |
3622 | INIT_WORK_ONSTACK(&wfc.work, work_for_cpu_fn); |
3623 | schedule_work_on(cpu, &wfc.work); | |
3624 | flush_work(&wfc.work); | |
2d3854a3 RR |
3625 | return wfc.ret; |
3626 | } | |
3627 | EXPORT_SYMBOL_GPL(work_on_cpu); | |
3628 | #endif /* CONFIG_SMP */ | |
3629 | ||
a0a1a5fd TH |
3630 | #ifdef CONFIG_FREEZER |
3631 | ||
3632 | /** | |
3633 | * freeze_workqueues_begin - begin freezing workqueues | |
3634 | * | |
58a69cb4 TH |
3635 | * Start freezing workqueues. After this function returns, all freezable |
3636 | * workqueues will queue new works to their frozen_works list instead of | |
706026c2 | 3637 | * pool->worklist. |
a0a1a5fd TH |
3638 | * |
3639 | * CONTEXT: | |
d565ed63 | 3640 | * Grabs and releases workqueue_lock and pool->lock's. |
a0a1a5fd TH |
3641 | */ |
3642 | void freeze_workqueues_begin(void) | |
3643 | { | |
a0a1a5fd TH |
3644 | unsigned int cpu; |
3645 | ||
3646 | spin_lock(&workqueue_lock); | |
3647 | ||
3648 | BUG_ON(workqueue_freezing); | |
3649 | workqueue_freezing = true; | |
3650 | ||
706026c2 | 3651 | for_each_wq_cpu(cpu) { |
35b6bb63 | 3652 | struct worker_pool *pool; |
bdbc5dd7 | 3653 | struct workqueue_struct *wq; |
8b03ae3c | 3654 | |
38db41d9 | 3655 | for_each_std_worker_pool(pool, cpu) { |
a1056305 | 3656 | spin_lock_irq(&pool->lock); |
d565ed63 | 3657 | |
35b6bb63 TH |
3658 | WARN_ON_ONCE(pool->flags & POOL_FREEZING); |
3659 | pool->flags |= POOL_FREEZING; | |
db7bccf4 | 3660 | |
a1056305 TH |
3661 | list_for_each_entry(wq, &workqueues, list) { |
3662 | struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); | |
a0a1a5fd | 3663 | |
a1056305 TH |
3664 | if (cwq && cwq->pool == pool && |
3665 | (wq->flags & WQ_FREEZABLE)) | |
3666 | cwq->max_active = 0; | |
3667 | } | |
8b03ae3c | 3668 | |
a1056305 TH |
3669 | spin_unlock_irq(&pool->lock); |
3670 | } | |
a0a1a5fd TH |
3671 | } |
3672 | ||
3673 | spin_unlock(&workqueue_lock); | |
3674 | } | |
3675 | ||
3676 | /** | |
58a69cb4 | 3677 | * freeze_workqueues_busy - are freezable workqueues still busy? |
a0a1a5fd TH |
3678 | * |
3679 | * Check whether freezing is complete. This function must be called | |
3680 | * between freeze_workqueues_begin() and thaw_workqueues(). | |
3681 | * | |
3682 | * CONTEXT: | |
3683 | * Grabs and releases workqueue_lock. | |
3684 | * | |
3685 | * RETURNS: | |
58a69cb4 TH |
3686 | * %true if some freezable workqueues are still busy. %false if freezing |
3687 | * is complete. | |
a0a1a5fd TH |
3688 | */ |
3689 | bool freeze_workqueues_busy(void) | |
3690 | { | |
a0a1a5fd TH |
3691 | unsigned int cpu; |
3692 | bool busy = false; | |
3693 | ||
3694 | spin_lock(&workqueue_lock); | |
3695 | ||
3696 | BUG_ON(!workqueue_freezing); | |
3697 | ||
706026c2 | 3698 | for_each_wq_cpu(cpu) { |
bdbc5dd7 | 3699 | struct workqueue_struct *wq; |
a0a1a5fd TH |
3700 | /* |
3701 | * nr_active is monotonically decreasing. It's safe | |
3702 | * to peek without lock. | |
3703 | */ | |
3704 | list_for_each_entry(wq, &workqueues, list) { | |
3705 | struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); | |
3706 | ||
58a69cb4 | 3707 | if (!cwq || !(wq->flags & WQ_FREEZABLE)) |
a0a1a5fd TH |
3708 | continue; |
3709 | ||
3710 | BUG_ON(cwq->nr_active < 0); | |
3711 | if (cwq->nr_active) { | |
3712 | busy = true; | |
3713 | goto out_unlock; | |
3714 | } | |
3715 | } | |
3716 | } | |
3717 | out_unlock: | |
3718 | spin_unlock(&workqueue_lock); | |
3719 | return busy; | |
3720 | } | |
3721 | ||
3722 | /** | |
3723 | * thaw_workqueues - thaw workqueues | |
3724 | * | |
3725 | * Thaw workqueues. Normal queueing is restored and all collected | |
706026c2 | 3726 | * frozen works are transferred to their respective pool worklists. |
a0a1a5fd TH |
3727 | * |
3728 | * CONTEXT: | |
d565ed63 | 3729 | * Grabs and releases workqueue_lock and pool->lock's. |
a0a1a5fd TH |
3730 | */ |
3731 | void thaw_workqueues(void) | |
3732 | { | |
a0a1a5fd TH |
3733 | unsigned int cpu; |
3734 | ||
3735 | spin_lock(&workqueue_lock); | |
3736 | ||
3737 | if (!workqueue_freezing) | |
3738 | goto out_unlock; | |
3739 | ||
706026c2 | 3740 | for_each_wq_cpu(cpu) { |
4ce62e9e | 3741 | struct worker_pool *pool; |
bdbc5dd7 | 3742 | struct workqueue_struct *wq; |
8b03ae3c | 3743 | |
38db41d9 | 3744 | for_each_std_worker_pool(pool, cpu) { |
a1056305 | 3745 | spin_lock_irq(&pool->lock); |
d565ed63 | 3746 | |
35b6bb63 TH |
3747 | WARN_ON_ONCE(!(pool->flags & POOL_FREEZING)); |
3748 | pool->flags &= ~POOL_FREEZING; | |
db7bccf4 | 3749 | |
a1056305 TH |
3750 | list_for_each_entry(wq, &workqueues, list) { |
3751 | struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); | |
a0a1a5fd | 3752 | |
a1056305 TH |
3753 | if (!cwq || cwq->pool != pool || |
3754 | !(wq->flags & WQ_FREEZABLE)) | |
3755 | continue; | |
a0a1a5fd | 3756 | |
a1056305 TH |
3757 | /* restore max_active and repopulate worklist */ |
3758 | cwq_set_max_active(cwq, wq->saved_max_active); | |
3759 | } | |
8b03ae3c | 3760 | |
4ce62e9e | 3761 | wake_up_worker(pool); |
a1056305 TH |
3762 | |
3763 | spin_unlock_irq(&pool->lock); | |
d565ed63 | 3764 | } |
a0a1a5fd TH |
3765 | } |
3766 | ||
3767 | workqueue_freezing = false; | |
3768 | out_unlock: | |
3769 | spin_unlock(&workqueue_lock); | |
3770 | } | |
3771 | #endif /* CONFIG_FREEZER */ | |
3772 | ||
6ee0578b | 3773 | static int __init init_workqueues(void) |
1da177e4 | 3774 | { |
c34056a3 TH |
3775 | unsigned int cpu; |
3776 | ||
7c3eed5c TH |
3777 | /* make sure we have enough bits for OFFQ pool ID */ |
3778 | BUILD_BUG_ON((1LU << (BITS_PER_LONG - WORK_OFFQ_POOL_SHIFT)) < | |
6be19588 | 3779 | WORK_CPU_END * NR_STD_WORKER_POOLS); |
b5490077 | 3780 | |
65758202 | 3781 | cpu_notifier(workqueue_cpu_up_callback, CPU_PRI_WORKQUEUE_UP); |
a5b4e57d | 3782 | hotcpu_notifier(workqueue_cpu_down_callback, CPU_PRI_WORKQUEUE_DOWN); |
8b03ae3c | 3783 | |
706026c2 TH |
3784 | /* initialize CPU pools */ |
3785 | for_each_wq_cpu(cpu) { | |
4ce62e9e | 3786 | struct worker_pool *pool; |
8b03ae3c | 3787 | |
38db41d9 | 3788 | for_each_std_worker_pool(pool, cpu) { |
d565ed63 | 3789 | spin_lock_init(&pool->lock); |
ec22ca5e | 3790 | pool->cpu = cpu; |
24647570 | 3791 | pool->flags |= POOL_DISASSOCIATED; |
4ce62e9e TH |
3792 | INIT_LIST_HEAD(&pool->worklist); |
3793 | INIT_LIST_HEAD(&pool->idle_list); | |
c9e7cf27 | 3794 | hash_init(pool->busy_hash); |
e7577c50 | 3795 | |
4ce62e9e TH |
3796 | init_timer_deferrable(&pool->idle_timer); |
3797 | pool->idle_timer.function = idle_worker_timeout; | |
3798 | pool->idle_timer.data = (unsigned long)pool; | |
e22bee78 | 3799 | |
706026c2 | 3800 | setup_timer(&pool->mayday_timer, pool_mayday_timeout, |
4ce62e9e TH |
3801 | (unsigned long)pool); |
3802 | ||
b2eb83d1 | 3803 | mutex_init(&pool->assoc_mutex); |
4ce62e9e | 3804 | ida_init(&pool->worker_ida); |
9daf9e67 TH |
3805 | |
3806 | /* alloc pool ID */ | |
3807 | BUG_ON(worker_pool_assign_id(pool)); | |
4ce62e9e | 3808 | } |
8b03ae3c TH |
3809 | } |
3810 | ||
e22bee78 | 3811 | /* create the initial worker */ |
706026c2 | 3812 | for_each_online_wq_cpu(cpu) { |
4ce62e9e | 3813 | struct worker_pool *pool; |
e22bee78 | 3814 | |
38db41d9 | 3815 | for_each_std_worker_pool(pool, cpu) { |
4ce62e9e TH |
3816 | struct worker *worker; |
3817 | ||
24647570 TH |
3818 | if (cpu != WORK_CPU_UNBOUND) |
3819 | pool->flags &= ~POOL_DISASSOCIATED; | |
3820 | ||
bc2ae0f5 | 3821 | worker = create_worker(pool); |
4ce62e9e | 3822 | BUG_ON(!worker); |
d565ed63 | 3823 | spin_lock_irq(&pool->lock); |
4ce62e9e | 3824 | start_worker(worker); |
d565ed63 | 3825 | spin_unlock_irq(&pool->lock); |
4ce62e9e | 3826 | } |
e22bee78 TH |
3827 | } |
3828 | ||
d320c038 | 3829 | system_wq = alloc_workqueue("events", 0, 0); |
1aabe902 | 3830 | system_highpri_wq = alloc_workqueue("events_highpri", WQ_HIGHPRI, 0); |
d320c038 | 3831 | system_long_wq = alloc_workqueue("events_long", 0, 0); |
f3421797 TH |
3832 | system_unbound_wq = alloc_workqueue("events_unbound", WQ_UNBOUND, |
3833 | WQ_UNBOUND_MAX_ACTIVE); | |
24d51add TH |
3834 | system_freezable_wq = alloc_workqueue("events_freezable", |
3835 | WQ_FREEZABLE, 0); | |
1aabe902 | 3836 | BUG_ON(!system_wq || !system_highpri_wq || !system_long_wq || |
ae930e0f | 3837 | !system_unbound_wq || !system_freezable_wq); |
6ee0578b | 3838 | return 0; |
1da177e4 | 3839 | } |
6ee0578b | 3840 | early_initcall(init_workqueues); |