1 /*-
2 * Copyright (c) 2000 Doug Rabson
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD: src/sys/kern/subr_taskqueue.c,v 1.69 2012/08/28 13:35:37 jhb Exp $"
27 */
28
29 #include <sys/param.h>
30 #include <sys/queue.h>
31 #include <sys/systm.h>
32 #include <sys/kernel.h>
33 #include <sys/taskqueue.h>
34 #include <sys/interrupt.h>
35 #include <sys/lock.h>
36 #include <sys/malloc.h>
37 #include <sys/kthread.h>
38 #include <sys/thread2.h>
39 #include <sys/spinlock.h>
40 #include <sys/spinlock2.h>
41 #include <sys/serialize.h>
42 #include <sys/proc.h>
43 #include <machine/varargs.h>
44
45 MALLOC_DEFINE(M_TASKQUEUE, "taskqueue", "Task Queues");
46
47 static STAILQ_HEAD(taskqueue_list, taskqueue) taskqueue_queues;
48 static struct lock taskqueue_queues_lock;
49
50 struct taskqueue {
51 STAILQ_ENTRY(taskqueue) tq_link;
52 STAILQ_HEAD(, task) tq_queue;
53 const char *tq_name;
54 taskqueue_enqueue_fn tq_enqueue;
55 void *tq_context;
56
57 struct task *tq_running;
58 struct spinlock tq_lock;
59 struct thread **tq_threads;
60 int tq_tcount;
61 int tq_flags;
62 int tq_callouts;
63 };
64
65 #define TQ_FLAGS_ACTIVE (1 << 0)
66 #define TQ_FLAGS_BLOCKED (1 << 1)
67 #define TQ_FLAGS_PENDING (1 << 2)
68
69 #define DT_CALLOUT_ARMED (1 << 0)
70
71 void
72 _timeout_task_init(struct taskqueue *queue, struct timeout_task *timeout_task,
73 int priority, task_fn_t func, void *context)
74 {
75
76 TASK_INIT(&timeout_task->t, priority, func, context);
77 callout_init(&timeout_task->c);
78 timeout_task->q = queue;
79 timeout_task->f = 0;
80 }
81
82 static void taskqueue_run(struct taskqueue *queue, int lock_held);
83
84 static __inline void
85 TQ_LOCK_INIT(struct taskqueue *tq)
86 {
87 spin_init(&tq->tq_lock);
88 }
89
90 static __inline void
91 TQ_LOCK_UNINIT(struct taskqueue *tq)
92 {
93 spin_uninit(&tq->tq_lock);
94 }
95
96 static __inline void
97 TQ_LOCK(struct taskqueue *tq)
98 {
99 spin_lock(&tq->tq_lock);
100 }
101
102 static __inline void
103 TQ_UNLOCK(struct taskqueue *tq)
104 {
105 spin_unlock(&tq->tq_lock);
106 }
107
108 static __inline void
109 TQ_SLEEP(struct taskqueue *tq, void *ident, const char *wmesg)
110 {
111 ssleep(ident, &tq->tq_lock, 0, wmesg, 0);
112 }
113
114 struct taskqueue *
115 taskqueue_create(const char *name, int mflags,
116 taskqueue_enqueue_fn enqueue, void *context)
117 {
118 struct taskqueue *queue;
119
120 queue = kmalloc(sizeof(*queue), M_TASKQUEUE, mflags | M_ZERO);
121 if (!queue)
122 return NULL;
123 STAILQ_INIT(&queue->tq_queue);
124 queue->tq_name = name;
125 queue->tq_enqueue = enqueue;
126 queue->tq_context = context;
127 queue->tq_flags |= TQ_FLAGS_ACTIVE;
128 TQ_LOCK_INIT(queue);
129
130 lockmgr(&taskqueue_queues_lock, LK_EXCLUSIVE);
131 STAILQ_INSERT_TAIL(&taskqueue_queues, queue, tq_link);
132 lockmgr(&taskqueue_queues_lock, LK_RELEASE);
133
134 return queue;
135 }
136
137 static void
138 taskqueue_terminate(struct thread **pp, struct taskqueue *tq)
139 {
140 while(tq->tq_tcount > 0) {
141 wakeup(tq);
142 TQ_SLEEP(tq, pp, "taskqueue_terminate");
143 }
144 }
145
146 void
147 taskqueue_free(struct taskqueue *queue)
148 {
149 TQ_LOCK(queue);
150 queue->tq_flags &= ~TQ_FLAGS_ACTIVE;
151 taskqueue_run(queue, 1);
152 taskqueue_terminate(queue->tq_threads, queue);
153 TQ_UNLOCK(queue);
154
155 lockmgr(&taskqueue_queues_lock, LK_EXCLUSIVE);
156 STAILQ_REMOVE(&taskqueue_queues, queue, taskqueue, tq_link);
157 lockmgr(&taskqueue_queues_lock, LK_RELEASE);
158
159 TQ_LOCK_UNINIT(queue);
160
161 kfree(queue, M_TASKQUEUE);
162 }
163
164 struct taskqueue *
165 taskqueue_find(const char *name)
166 {
167 struct taskqueue *queue;
168
169 lockmgr(&taskqueue_queues_lock, LK_EXCLUSIVE);
170 STAILQ_FOREACH(queue, &taskqueue_queues, tq_link) {
171 if (!strcmp(queue->tq_name, name)) {
172 lockmgr(&taskqueue_queues_lock, LK_RELEASE);
173 return queue;
174 }
175 }
176 lockmgr(&taskqueue_queues_lock, LK_RELEASE);
177 return NULL;
178 }
179
180 /*
181 * NOTE! If using the per-cpu taskqueues ``taskqueue_thread[mycpuid]'',
182 * be sure NOT TO SHARE the ``task'' between CPUs. TASKS ARE NOT LOCKED.
183 * So either use a throwaway task which will only be enqueued once, or
184 * use one task per CPU!
185 */
186 static int
187 taskqueue_enqueue_locked(struct taskqueue *queue, struct task *task)
188 {
189 struct task *ins;
190 struct task *prev;
191
192 /*
193 * Don't allow new tasks on a queue which is being freed.
194 */
195 if ((queue->tq_flags & TQ_FLAGS_ACTIVE) == 0) {
196 TQ_UNLOCK(queue);
197 return EPIPE;
198 }
199
200 /*
201 * Count multiple enqueues.
202 */
203 if (task->ta_pending) {
204 task->ta_pending++;
205 return 0;
206 }
207
208 /*
209 * Optimise the case when all tasks have the same priority.
210 */
211 prev = STAILQ_LAST(&queue->tq_queue, task, ta_link);
212 if (!prev || prev->ta_priority >= task->ta_priority) {
213 STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link);
214 } else {
215 prev = NULL;
216 for (ins = STAILQ_FIRST(&queue->tq_queue); ins;
217 prev = ins, ins = STAILQ_NEXT(ins, ta_link))
218 if (ins->ta_priority < task->ta_priority)
219 break;
220
221 if (prev)
222 STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link);
223 else
224 STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link);
225 }
226
227 task->ta_pending = 1;
228 if ((queue->tq_flags & TQ_FLAGS_BLOCKED) == 0) {
229 if (queue->tq_enqueue)
230 queue->tq_enqueue(queue->tq_context);
231 } else {
232 queue->tq_flags |= TQ_FLAGS_PENDING;
233 }
234
235 return 0;
236 }
237
238 int
239 taskqueue_enqueue(struct taskqueue *queue, struct task *task)
240 {
241 int res;
242
243 TQ_LOCK(queue);
244 res = taskqueue_enqueue_locked(queue, task);
245 TQ_UNLOCK(queue);
246
247 return (res);
248 }
249
250 static void
251 taskqueue_timeout_func(void *arg)
252 {
253 struct taskqueue *queue;
254 struct timeout_task *timeout_task;
255
256 timeout_task = arg;
257 queue = timeout_task->q;
258 KASSERT((timeout_task->f & DT_CALLOUT_ARMED) != 0, ("Stray timeout"));
259 timeout_task->f &= ~DT_CALLOUT_ARMED;
260 queue->tq_callouts--;
261 taskqueue_enqueue_locked(timeout_task->q, &timeout_task->t);
262 }
263
264 int
265 taskqueue_enqueue_timeout(struct taskqueue *queue,
266 struct timeout_task *timeout_task, int ticks)
267 {
268 int res;
269
270 TQ_LOCK(queue);
271 KASSERT(timeout_task->q == NULL || timeout_task->q == queue,
272 ("Migrated queue"));
273 timeout_task->q = queue;
274 res = timeout_task->t.ta_pending;
275 if (ticks == 0) {
276 taskqueue_enqueue_locked(queue, &timeout_task->t);
277 } else {
278 if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
279 res++;
280 } else {
281 queue->tq_callouts++;
282 timeout_task->f |= DT_CALLOUT_ARMED;
283 }
284 callout_reset(&timeout_task->c, ticks, taskqueue_timeout_func,
285 timeout_task);
286 }
287 TQ_UNLOCK(queue);
288 return (res);
289 }
290
291 void
292 taskqueue_block(struct taskqueue *queue)
293 {
294 TQ_LOCK(queue);
295 queue->tq_flags |= TQ_FLAGS_BLOCKED;
296 TQ_UNLOCK(queue);
297 }
298
299 void
300 taskqueue_unblock(struct taskqueue *queue)
301 {
302 TQ_LOCK(queue);
303 queue->tq_flags &= ~TQ_FLAGS_BLOCKED;
304 if (queue->tq_flags & TQ_FLAGS_PENDING) {
305 queue->tq_flags &= ~TQ_FLAGS_PENDING;
306 if (queue->tq_enqueue)
307 queue->tq_enqueue(queue->tq_context);
308 }
309 TQ_UNLOCK(queue);
310 }
311
312 void
313 taskqueue_run(struct taskqueue *queue, int lock_held)
314 {
315 struct task *task;
316 int pending;
317
318 if (lock_held == 0)
319 TQ_LOCK(queue);
320 while (STAILQ_FIRST(&queue->tq_queue)) {
321 /*
322 * Carefully remove the first task from the queue and
323 * zero its pending count.
324 */
325 task = STAILQ_FIRST(&queue->tq_queue);
326 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link);
327 pending = task->ta_pending;
328 task->ta_pending = 0;
329 queue->tq_running = task;
330 TQ_UNLOCK(queue);
331
332 task->ta_func(task->ta_context, pending);
333
334 TQ_LOCK(queue);
335 queue->tq_running = NULL;
336 wakeup(task);
337 }
338 if (lock_held == 0)
339 TQ_UNLOCK(queue);
340 }
341
342 static int
343 taskqueue_cancel_locked(struct taskqueue *queue, struct task *task,
344 u_int *pendp)
345 {
346
347 if (task->ta_pending > 0)
348 STAILQ_REMOVE(&queue->tq_queue, task, task, ta_link);
349 if (pendp != NULL)
350 *pendp = task->ta_pending;
351 task->ta_pending = 0;
352 return (task == queue->tq_running ? EBUSY : 0);
353 }
354
355 int
356 taskqueue_cancel(struct taskqueue *queue, struct task *task, u_int *pendp)
357 {
358 u_int pending;
359 int error;
360
361 TQ_LOCK(queue);
362 pending = task->ta_pending;
363 error = taskqueue_cancel_locked(queue, task, pendp);
364 TQ_UNLOCK(queue);
365
366 return (error);
367 }
368
369 int
370 taskqueue_cancel_timeout(struct taskqueue *queue,
371 struct timeout_task *timeout_task, u_int *pendp)
372 {
373 u_int pending, pending1;
374 int error;
375
376 TQ_LOCK(queue);
377 pending = !!callout_stop(&timeout_task->c);
378 error = taskqueue_cancel_locked(queue, &timeout_task->t, &pending1);
379 if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
380 timeout_task->f &= ~DT_CALLOUT_ARMED;
381 queue->tq_callouts--;
382 }
383 TQ_UNLOCK(queue);
384
385 if (pendp != NULL)
386 *pendp = pending + pending1;
387 return (error);
388 }
389
390 void
391 taskqueue_drain(struct taskqueue *queue, struct task *task)
392 {
393 TQ_LOCK(queue);
394 while (task->ta_pending != 0 || task == queue->tq_running)
395 TQ_SLEEP(queue, task, "-");
396 TQ_UNLOCK(queue);
397 }
398
399 void
400 taskqueue_drain_timeout(struct taskqueue *queue,
401 struct timeout_task *timeout_task)
402 {
403
404 callout_stop_sync(&timeout_task->c);
405 taskqueue_drain(queue, &timeout_task->t);
406 }
407
408 static void
409 taskqueue_swi_enqueue(void *context)
410 {
411 setsofttq();
412 }
413
414 static void
415 taskqueue_swi_run(void *arg, void *frame)
416 {
417 taskqueue_run(taskqueue_swi, 0);
418 }
419
420 static void
421 taskqueue_swi_mp_run(void *arg, void *frame)
422 {
423 taskqueue_run(taskqueue_swi_mp, 0);
424 }
425
426 int
427 taskqueue_start_threads(struct taskqueue **tqp, int count, int pri, int ncpu,
428 const char *fmt, ...)
429 {
430 __va_list ap;
431 struct thread *td;
432 struct taskqueue *tq;
433 int i, error, cpu;
434 char ktname[MAXCOMLEN];
435
436 if (count <= 0)
437 return EINVAL;
438
439 tq = *tqp;
440 cpu = ncpu;
441
442 __va_start(ap, fmt);
443 kvsnprintf(ktname, MAXCOMLEN, fmt, ap);
444 __va_end(ap);
445
446 tq->tq_threads = kmalloc(sizeof(struct thread *) * count, M_TASKQUEUE,
447 M_WAITOK | M_ZERO);
448
449 for (i = 0; i < count; i++) {
450 /*
451 * If no specific cpu was specified and more than one thread
452 * is to be created, we distribute the threads amongst all
453 * cpus.
454 */
455 if ((ncpu <= -1) && (count > 1))
456 cpu = i%ncpus;
457
458 if (count == 1) {
459 error = lwkt_create(taskqueue_thread_loop, tqp,
460 &tq->tq_threads[i], NULL,
461 TDF_NOSTART, cpu,
462 "%s", ktname);
463 } else {
464 error = lwkt_create(taskqueue_thread_loop, tqp,
465 &tq->tq_threads[i], NULL,
466 TDF_NOSTART, cpu,
467 "%s_%d", ktname, i);
468 }
469 if (error) {
470 kprintf("%s: lwkt_create(%s): error %d", __func__,
471 ktname, error);
472 tq->tq_threads[i] = NULL;
473 } else {
474 td = tq->tq_threads[i];
475 lwkt_setpri_initial(td, pri);
476 lwkt_schedule(td);
477 tq->tq_tcount++;
478 }
479 }
480
481 return 0;
482 }
483
484 void
485 taskqueue_thread_loop(void *arg)
486 {
487 struct taskqueue **tqp, *tq;
488
489 tqp = arg;
490 tq = *tqp;
491 TQ_LOCK(tq);
492 while ((tq->tq_flags & TQ_FLAGS_ACTIVE) != 0) {
493 taskqueue_run(tq, 1);
494 TQ_SLEEP(tq, tq, "tqthr");
495 }
496
497 /* rendezvous with thread that asked us to terminate */
498 tq->tq_tcount--;
499 wakeup_one(tq->tq_threads);
500 TQ_UNLOCK(tq);
501 lwkt_exit();
502 }
503
504 void
505 taskqueue_thread_enqueue(void *context)
506 {
507 struct taskqueue **tqp, *tq;
508
509 tqp = context;
510 tq = *tqp;
511
512 wakeup_one(tq);
513 }
514
515 TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, 0,
516 register_swi(SWI_TQ, taskqueue_swi_run, NULL, "swi_taskq", NULL, -1));
517 /*
518 * XXX: possibly use a different SWI_TQ_MP or so.
519 * related: sys/interrupt.h
520 * related: platform/XXX/isa/ipl_funcs.c
521 */
522 TASKQUEUE_DEFINE(swi_mp, taskqueue_swi_enqueue, 0,
523 register_swi_mp(SWI_TQ, taskqueue_swi_mp_run, NULL, "swi_mp_taskq", NULL,
524 -1));
525
526 struct taskqueue *taskqueue_thread[MAXCPU];
527
528 static void
529 taskqueue_init(void)
530 {
531 int cpu;
532
533 lockinit(&taskqueue_queues_lock, "tqqueues", 0, 0);
534 STAILQ_INIT(&taskqueue_queues);
535
536 for (cpu = 0; cpu < ncpus; cpu++) {
537 taskqueue_thread[cpu] = taskqueue_create("thread", M_INTWAIT,
538 taskqueue_thread_enqueue, &taskqueue_thread[cpu]);
539 taskqueue_start_threads(&taskqueue_thread[cpu], 1,
540 TDPRI_KERN_DAEMON, cpu, "taskq_cpu %d", cpu);
541 }
542 }
543
544 SYSINIT(taskqueueinit, SI_SUB_PRE_DRIVERS, SI_ORDER_ANY, taskqueue_init, NULL);
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