xref: /freebsd/sys/kern/subr_taskqueue.c (revision acc1a9ef) 
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 
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
29 
30 #include <sys/param.h>
31 #include <sys/systm.h>
32 #include <sys/bus.h>
33 #include <sys/cpuset.h>
34 #include <sys/interrupt.h>
35 #include <sys/kernel.h>
36 #include <sys/kthread.h>
37 #include <sys/limits.h>
38 #include <sys/lock.h>
39 #include <sys/malloc.h>
40 #include <sys/mutex.h>
41 #include <sys/proc.h>
42 #include <sys/sched.h>
43 #include <sys/taskqueue.h>
44 #include <sys/unistd.h>
45 #include <machine/stdarg.h>
46 
47 static MALLOC_DEFINE(M_TASKQUEUE, "taskqueue", "Task Queues");
48 static void	*taskqueue_giant_ih;
49 static void	*taskqueue_ih;
50 static void	 taskqueue_fast_enqueue(void *);
51 static void	 taskqueue_swi_enqueue(void *);
52 static void	 taskqueue_swi_giant_enqueue(void *);
53 
54 struct taskqueue_busy {
55 	struct task	*tb_running;
56 	TAILQ_ENTRY(taskqueue_busy) tb_link;
57 };
58 
59 struct task * const TB_DRAIN_WAITER = (struct task *)0x1;
60 
61 struct taskqueue {
62 	STAILQ_HEAD(, task)	tq_queue;
63 	taskqueue_enqueue_fn	tq_enqueue;
64 	void			*tq_context;
65 	TAILQ_HEAD(, taskqueue_busy) tq_active;
66 	struct mtx		tq_mutex;
67 	struct thread		**tq_threads;
68 	int			tq_tcount;
69 	int			tq_spin;
70 	int			tq_flags;
71 	int			tq_callouts;
72 	taskqueue_callback_fn	tq_callbacks[TASKQUEUE_NUM_CALLBACKS];
73 	void			*tq_cb_contexts[TASKQUEUE_NUM_CALLBACKS];
74 };
75 
76 #define	TQ_FLAGS_ACTIVE		(1 << 0)
77 #define	TQ_FLAGS_BLOCKED	(1 << 1)
78 #define	TQ_FLAGS_UNLOCKED_ENQUEUE	(1 << 2)
79 
80 #define	DT_CALLOUT_ARMED	(1 << 0)
81 
82 #define	TQ_LOCK(tq)							\
83 	do {								\
84 		if ((tq)->tq_spin)					\
85 			mtx_lock_spin(&(tq)->tq_mutex);			\
86 		else							\
87 			mtx_lock(&(tq)->tq_mutex);			\
88 	} while (0)
89 #define	TQ_ASSERT_LOCKED(tq)	mtx_assert(&(tq)->tq_mutex, MA_OWNED)
90 
91 #define	TQ_UNLOCK(tq)							\
92 	do {								\
93 		if ((tq)->tq_spin)					\
94 			mtx_unlock_spin(&(tq)->tq_mutex);		\
95 		else							\
96 			mtx_unlock(&(tq)->tq_mutex);			\
97 	} while (0)
98 #define	TQ_ASSERT_UNLOCKED(tq)	mtx_assert(&(tq)->tq_mutex, MA_NOTOWNED)
99 
100 void
101 _timeout_task_init(struct taskqueue *queue, struct timeout_task *timeout_task,
102     int priority, task_fn_t func, void *context)
103 {
104 
105 	TASK_INIT(&timeout_task->t, priority, func, context);
106 	callout_init_mtx(&timeout_task->c, &queue->tq_mutex,
107 	    CALLOUT_RETURNUNLOCKED);
108 	timeout_task->q = queue;
109 	timeout_task->f = 0;
110 }
111 
112 static __inline int
113 TQ_SLEEP(struct taskqueue *tq, void *p, struct mtx *m, int pri, const char *wm,
114     int t)
115 {
116 	if (tq->tq_spin)
117 		return (msleep_spin(p, m, wm, t));
118 	return (msleep(p, m, pri, wm, t));
119 }
120 
121 static struct taskqueue *
122 _taskqueue_create(const char *name __unused, int mflags,
123 		 taskqueue_enqueue_fn enqueue, void *context,
124 		 int mtxflags, const char *mtxname)
125 {
126 	struct taskqueue *queue;
127 
128 	queue = malloc(sizeof(struct taskqueue), M_TASKQUEUE, mflags | M_ZERO);
129 	if (!queue)
130 		return NULL;
131 
132 	STAILQ_INIT(&queue->tq_queue);
133 	TAILQ_INIT(&queue->tq_active);
134 	queue->tq_enqueue = enqueue;
135 	queue->tq_context = context;
136 	queue->tq_spin = (mtxflags & MTX_SPIN) != 0;
137 	queue->tq_flags |= TQ_FLAGS_ACTIVE;
138 	if (enqueue == taskqueue_fast_enqueue ||
139 	    enqueue == taskqueue_swi_enqueue ||
140 	    enqueue == taskqueue_swi_giant_enqueue ||
141 	    enqueue == taskqueue_thread_enqueue)
142 		queue->tq_flags |= TQ_FLAGS_UNLOCKED_ENQUEUE;
143 	mtx_init(&queue->tq_mutex, mtxname, NULL, mtxflags);
144 
145 	return queue;
146 }
147 
148 struct taskqueue *
149 taskqueue_create(const char *name, int mflags,
150 		 taskqueue_enqueue_fn enqueue, void *context)
151 {
152 	return _taskqueue_create(name, mflags, enqueue, context,
153 			MTX_DEF, "taskqueue");
154 }
155 
156 void
157 taskqueue_set_callback(struct taskqueue *queue,
158     enum taskqueue_callback_type cb_type, taskqueue_callback_fn callback,
159     void *context)
160 {
161 
162 	KASSERT(((cb_type >= TASKQUEUE_CALLBACK_TYPE_MIN) &&
163 	    (cb_type <= TASKQUEUE_CALLBACK_TYPE_MAX)),
164 	    ("Callback type %d not valid, must be %d-%d", cb_type,
165 	    TASKQUEUE_CALLBACK_TYPE_MIN, TASKQUEUE_CALLBACK_TYPE_MAX));
166 	KASSERT((queue->tq_callbacks[cb_type] == NULL),
167 	    ("Re-initialization of taskqueue callback?"));
168 
169 	queue->tq_callbacks[cb_type] = callback;
170 	queue->tq_cb_contexts[cb_type] = context;
171 }
172 
173 /*
174  * Signal a taskqueue thread to terminate.
175  */
176 static void
177 taskqueue_terminate(struct thread **pp, struct taskqueue *tq)
178 {
179 
180 	while (tq->tq_tcount > 0 || tq->tq_callouts > 0) {
181 		wakeup(tq);
182 		TQ_SLEEP(tq, pp, &tq->tq_mutex, PWAIT, "taskqueue_destroy", 0);
183 	}
184 }
185 
186 void
187 taskqueue_free(struct taskqueue *queue)
188 {
189 
190 	TQ_LOCK(queue);
191 	queue->tq_flags &= ~TQ_FLAGS_ACTIVE;
192 	taskqueue_terminate(queue->tq_threads, queue);
193 	KASSERT(TAILQ_EMPTY(&queue->tq_active), ("Tasks still running?"));
194 	KASSERT(queue->tq_callouts == 0, ("Armed timeout tasks"));
195 	mtx_destroy(&queue->tq_mutex);
196 	free(queue->tq_threads, M_TASKQUEUE);
197 	free(queue, M_TASKQUEUE);
198 }
199 
200 static int
201 taskqueue_enqueue_locked(struct taskqueue *queue, struct task *task)
202 {
203 	struct task *ins;
204 	struct task *prev;
205 
206 	/*
207 	 * Count multiple enqueues.
208 	 */
209 	if (task->ta_pending) {
210 		if (task->ta_pending < USHRT_MAX)
211 			task->ta_pending++;
212 		TQ_UNLOCK(queue);
213 		return (0);
214 	}
215 
216 	/*
217 	 * Optimise the case when all tasks have the same priority.
218 	 */
219 	prev = STAILQ_LAST(&queue->tq_queue, task, ta_link);
220 	if (!prev || prev->ta_priority >= task->ta_priority) {
221 		STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link);
222 	} else {
223 		prev = NULL;
224 		for (ins = STAILQ_FIRST(&queue->tq_queue); ins;
225 		     prev = ins, ins = STAILQ_NEXT(ins, ta_link))
226 			if (ins->ta_priority < task->ta_priority)
227 				break;
228 
229 		if (prev)
230 			STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link);
231 		else
232 			STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link);
233 	}
234 
235 	task->ta_pending = 1;
236 	if ((queue->tq_flags & TQ_FLAGS_UNLOCKED_ENQUEUE) != 0)
237 		TQ_UNLOCK(queue);
238 	if ((queue->tq_flags & TQ_FLAGS_BLOCKED) == 0)
239 		queue->tq_enqueue(queue->tq_context);
240 	if ((queue->tq_flags & TQ_FLAGS_UNLOCKED_ENQUEUE) == 0)
241 		TQ_UNLOCK(queue);
242 
243 	/* Return with lock released. */
244 	return (0);
245 }
246 
247 int
248 taskqueue_enqueue(struct taskqueue *queue, struct task *task)
249 {
250 	int res;
251 
252 	TQ_LOCK(queue);
253 	res = taskqueue_enqueue_locked(queue, task);
254 	/* The lock is released inside. */
255 
256 	return (res);
257 }
258 
259 static void
260 taskqueue_timeout_func(void *arg)
261 {
262 	struct taskqueue *queue;
263 	struct timeout_task *timeout_task;
264 
265 	timeout_task = arg;
266 	queue = timeout_task->q;
267 	KASSERT((timeout_task->f & DT_CALLOUT_ARMED) != 0, ("Stray timeout"));
268 	timeout_task->f &= ~DT_CALLOUT_ARMED;
269 	queue->tq_callouts--;
270 	taskqueue_enqueue_locked(timeout_task->q, &timeout_task->t);
271 	/* The lock is released inside. */
272 }
273 
274 int
275 taskqueue_enqueue_timeout(struct taskqueue *queue,
276     struct timeout_task *timeout_task, int ticks)
277 {
278 	int res;
279 
280 	TQ_LOCK(queue);
281 	KASSERT(timeout_task->q == NULL || timeout_task->q == queue,
282 	    ("Migrated queue"));
283 	KASSERT(!queue->tq_spin, ("Timeout for spin-queue"));
284 	timeout_task->q = queue;
285 	res = timeout_task->t.ta_pending;
286 	if (ticks == 0) {
287 		taskqueue_enqueue_locked(queue, &timeout_task->t);
288 		/* The lock is released inside. */
289 	} else {
290 		if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
291 			res++;
292 		} else {
293 			queue->tq_callouts++;
294 			timeout_task->f |= DT_CALLOUT_ARMED;
295 			if (ticks < 0)
296 				ticks = -ticks; /* Ignore overflow. */
297 		}
298 		if (ticks > 0) {
299 			callout_reset(&timeout_task->c, ticks,
300 			    taskqueue_timeout_func, timeout_task);
301 		}
302 		TQ_UNLOCK(queue);
303 	}
304 	return (res);
305 }
306 
307 static void
308 taskqueue_task_nop_fn(void *context, int pending)
309 {
310 }
311 
312 /*
313  * Block until all currently queued tasks in this taskqueue
314  * have begun execution.  Tasks queued during execution of
315  * this function are ignored.
316  */
317 static void
318 taskqueue_drain_tq_queue(struct taskqueue *queue)
319 {
320 	struct task t_barrier;
321 
322 	if (STAILQ_EMPTY(&queue->tq_queue))
323 		return;
324 
325 	/*
326 	 * Enqueue our barrier after all current tasks, but with
327 	 * the highest priority so that newly queued tasks cannot
328 	 * pass it.  Because of the high priority, we can not use
329 	 * taskqueue_enqueue_locked directly (which drops the lock
330 	 * anyway) so just insert it at tail while we have the
331 	 * queue lock.
332 	 */
333 	TASK_INIT(&t_barrier, USHRT_MAX, taskqueue_task_nop_fn, &t_barrier);
334 	STAILQ_INSERT_TAIL(&queue->tq_queue, &t_barrier, ta_link);
335 	t_barrier.ta_pending = 1;
336 
337 	/*
338 	 * Once the barrier has executed, all previously queued tasks
339 	 * have completed or are currently executing.
340 	 */
341 	while (t_barrier.ta_pending != 0)
342 		TQ_SLEEP(queue, &t_barrier, &queue->tq_mutex, PWAIT, "-", 0);
343 }
344 
345 /*
346  * Block until all currently executing tasks for this taskqueue
347  * complete.  Tasks that begin execution during the execution
348  * of this function are ignored.
349  */
350 static void
351 taskqueue_drain_tq_active(struct taskqueue *queue)
352 {
353 	struct taskqueue_busy tb_marker, *tb_first;
354 
355 	if (TAILQ_EMPTY(&queue->tq_active))
356 		return;
357 
358 	/* Block taskq_terminate().*/
359 	queue->tq_callouts++;
360 
361 	/*
362 	 * Wait for all currently executing taskqueue threads
363 	 * to go idle.
364 	 */
365 	tb_marker.tb_running = TB_DRAIN_WAITER;
366 	TAILQ_INSERT_TAIL(&queue->tq_active, &tb_marker, tb_link);
367 	while (TAILQ_FIRST(&queue->tq_active) != &tb_marker)
368 		TQ_SLEEP(queue, &tb_marker, &queue->tq_mutex, PWAIT, "-", 0);
369 	TAILQ_REMOVE(&queue->tq_active, &tb_marker, tb_link);
370 
371 	/*
372 	 * Wakeup any other drain waiter that happened to queue up
373 	 * without any intervening active thread.
374 	 */
375 	tb_first = TAILQ_FIRST(&queue->tq_active);
376 	if (tb_first != NULL && tb_first->tb_running == TB_DRAIN_WAITER)
377 		wakeup(tb_first);
378 
379 	/* Release taskqueue_terminate(). */
380 	queue->tq_callouts--;
381 	if ((queue->tq_flags & TQ_FLAGS_ACTIVE) == 0)
382 		wakeup_one(queue->tq_threads);
383 }
384 
385 void
386 taskqueue_block(struct taskqueue *queue)
387 {
388 
389 	TQ_LOCK(queue);
390 	queue->tq_flags |= TQ_FLAGS_BLOCKED;
391 	TQ_UNLOCK(queue);
392 }
393 
394 void
395 taskqueue_unblock(struct taskqueue *queue)
396 {
397 
398 	TQ_LOCK(queue);
399 	queue->tq_flags &= ~TQ_FLAGS_BLOCKED;
400 	if (!STAILQ_EMPTY(&queue->tq_queue))
401 		queue->tq_enqueue(queue->tq_context);
402 	TQ_UNLOCK(queue);
403 }
404 
405 static void
406 taskqueue_run_locked(struct taskqueue *queue)
407 {
408 	struct taskqueue_busy tb;
409 	struct taskqueue_busy *tb_first;
410 	struct task *task;
411 	int pending;
412 
413 	TQ_ASSERT_LOCKED(queue);
414 	tb.tb_running = NULL;
415 
416 	while (STAILQ_FIRST(&queue->tq_queue)) {
417 		TAILQ_INSERT_TAIL(&queue->tq_active, &tb, tb_link);
418 
419 		/*
420 		 * Carefully remove the first task from the queue and
421 		 * zero its pending count.
422 		 */
423 		task = STAILQ_FIRST(&queue->tq_queue);
424 		STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link);
425 		pending = task->ta_pending;
426 		task->ta_pending = 0;
427 		tb.tb_running = task;
428 		TQ_UNLOCK(queue);
429 
430 		task->ta_func(task->ta_context, pending);
431 
432 		TQ_LOCK(queue);
433 		tb.tb_running = NULL;
434 		wakeup(task);
435 
436 		TAILQ_REMOVE(&queue->tq_active, &tb, tb_link);
437 		tb_first = TAILQ_FIRST(&queue->tq_active);
438 		if (tb_first != NULL &&
439 		    tb_first->tb_running == TB_DRAIN_WAITER)
440 			wakeup(tb_first);
441 	}
442 }
443 
444 void
445 taskqueue_run(struct taskqueue *queue)
446 {
447 
448 	TQ_LOCK(queue);
449 	taskqueue_run_locked(queue);
450 	TQ_UNLOCK(queue);
451 }
452 
453 static int
454 task_is_running(struct taskqueue *queue, struct task *task)
455 {
456 	struct taskqueue_busy *tb;
457 
458 	TQ_ASSERT_LOCKED(queue);
459 	TAILQ_FOREACH(tb, &queue->tq_active, tb_link) {
460 		if (tb->tb_running == task)
461 			return (1);
462 	}
463 	return (0);
464 }
465 
466 static int
467 taskqueue_cancel_locked(struct taskqueue *queue, struct task *task,
468     u_int *pendp)
469 {
470 
471 	if (task->ta_pending > 0)
472 		STAILQ_REMOVE(&queue->tq_queue, task, task, ta_link);
473 	if (pendp != NULL)
474 		*pendp = task->ta_pending;
475 	task->ta_pending = 0;
476 	return (task_is_running(queue, task) ? EBUSY : 0);
477 }
478 
479 int
480 taskqueue_cancel(struct taskqueue *queue, struct task *task, u_int *pendp)
481 {
482 	int error;
483 
484 	TQ_LOCK(queue);
485 	error = taskqueue_cancel_locked(queue, task, pendp);
486 	TQ_UNLOCK(queue);
487 
488 	return (error);
489 }
490 
491 int
492 taskqueue_cancel_timeout(struct taskqueue *queue,
493     struct timeout_task *timeout_task, u_int *pendp)
494 {
495 	u_int pending, pending1;
496 	int error;
497 
498 	TQ_LOCK(queue);
499 	pending = !!(callout_stop(&timeout_task->c) > 0);
500 	error = taskqueue_cancel_locked(queue, &timeout_task->t, &pending1);
501 	if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
502 		timeout_task->f &= ~DT_CALLOUT_ARMED;
503 		queue->tq_callouts--;
504 	}
505 	TQ_UNLOCK(queue);
506 
507 	if (pendp != NULL)
508 		*pendp = pending + pending1;
509 	return (error);
510 }
511 
512 void
513 taskqueue_drain(struct taskqueue *queue, struct task *task)
514 {
515 
516 	if (!queue->tq_spin)
517 		WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
518 
519 	TQ_LOCK(queue);
520 	while (task->ta_pending != 0 || task_is_running(queue, task))
521 		TQ_SLEEP(queue, task, &queue->tq_mutex, PWAIT, "-", 0);
522 	TQ_UNLOCK(queue);
523 }
524 
525 void
526 taskqueue_drain_all(struct taskqueue *queue)
527 {
528 
529 	if (!queue->tq_spin)
530 		WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
531 
532 	TQ_LOCK(queue);
533 	taskqueue_drain_tq_queue(queue);
534 	taskqueue_drain_tq_active(queue);
535 	TQ_UNLOCK(queue);
536 }
537 
538 void
539 taskqueue_drain_timeout(struct taskqueue *queue,
540     struct timeout_task *timeout_task)
541 {
542 
543 	callout_drain(&timeout_task->c);
544 	taskqueue_drain(queue, &timeout_task->t);
545 }
546 
547 static void
548 taskqueue_swi_enqueue(void *context)
549 {
550 	swi_sched(taskqueue_ih, 0);
551 }
552 
553 static void
554 taskqueue_swi_run(void *dummy)
555 {
556 	taskqueue_run(taskqueue_swi);
557 }
558 
559 static void
560 taskqueue_swi_giant_enqueue(void *context)
561 {
562 	swi_sched(taskqueue_giant_ih, 0);
563 }
564 
565 static void
566 taskqueue_swi_giant_run(void *dummy)
567 {
568 	taskqueue_run(taskqueue_swi_giant);
569 }
570 
571 static int
572 _taskqueue_start_threads(struct taskqueue **tqp, int count, int pri,
573     cpuset_t *mask, const char *name, va_list ap)
574 {
575 	char ktname[MAXCOMLEN + 1];
576 	struct thread *td;
577 	struct taskqueue *tq;
578 	int i, error;
579 
580 	if (count <= 0)
581 		return (EINVAL);
582 
583 	vsnprintf(ktname, sizeof(ktname), name, ap);
584 	tq = *tqp;
585 
586 	tq->tq_threads = malloc(sizeof(struct thread *) * count, M_TASKQUEUE,
587 	    M_NOWAIT | M_ZERO);
588 	if (tq->tq_threads == NULL) {
589 		printf("%s: no memory for %s threads\n", __func__, ktname);
590 		return (ENOMEM);
591 	}
592 
593 	for (i = 0; i < count; i++) {
594 		if (count == 1)
595 			error = kthread_add(taskqueue_thread_loop, tqp, NULL,
596 			    &tq->tq_threads[i], RFSTOPPED, 0, "%s", ktname);
597 		else
598 			error = kthread_add(taskqueue_thread_loop, tqp, NULL,
599 			    &tq->tq_threads[i], RFSTOPPED, 0,
600 			    "%s_%d", ktname, i);
601 		if (error) {
602 			/* should be ok to continue, taskqueue_free will dtrt */
603 			printf("%s: kthread_add(%s): error %d", __func__,
604 			    ktname, error);
605 			tq->tq_threads[i] = NULL;		/* paranoid */
606 		} else
607 			tq->tq_tcount++;
608 	}
609 	for (i = 0; i < count; i++) {
610 		if (tq->tq_threads[i] == NULL)
611 			continue;
612 		td = tq->tq_threads[i];
613 		if (mask) {
614 			error = cpuset_setthread(td->td_tid, mask);
615 			/*
616 			 * Failing to pin is rarely an actual fatal error;
617 			 * it'll just affect performance.
618 			 */
619 			if (error)
620 				printf("%s: curthread=%llu: can't pin; "
621 				    "error=%d\n",
622 				    __func__,
623 				    (unsigned long long) td->td_tid,
624 				    error);
625 		}
626 		thread_lock(td);
627 		sched_prio(td, pri);
628 		sched_add(td, SRQ_BORING);
629 		thread_unlock(td);
630 	}
631 
632 	return (0);
633 }
634 
635 int
636 taskqueue_start_threads(struct taskqueue **tqp, int count, int pri,
637     const char *name, ...)
638 {
639 	va_list ap;
640 	int error;
641 
642 	va_start(ap, name);
643 	error = _taskqueue_start_threads(tqp, count, pri, NULL, name, ap);
644 	va_end(ap);
645 	return (error);
646 }
647 
648 int
649 taskqueue_start_threads_cpuset(struct taskqueue **tqp, int count, int pri,
650     cpuset_t *mask, const char *name, ...)
651 {
652 	va_list ap;
653 	int error;
654 
655 	va_start(ap, name);
656 	error = _taskqueue_start_threads(tqp, count, pri, mask, name, ap);
657 	va_end(ap);
658 	return (error);
659 }
660 
661 static inline void
662 taskqueue_run_callback(struct taskqueue *tq,
663     enum taskqueue_callback_type cb_type)
664 {
665 	taskqueue_callback_fn tq_callback;
666 
667 	TQ_ASSERT_UNLOCKED(tq);
668 	tq_callback = tq->tq_callbacks[cb_type];
669 	if (tq_callback != NULL)
670 		tq_callback(tq->tq_cb_contexts[cb_type]);
671 }
672 
673 void
674 taskqueue_thread_loop(void *arg)
675 {
676 	struct taskqueue **tqp, *tq;
677 
678 	tqp = arg;
679 	tq = *tqp;
680 	taskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_INIT);
681 	TQ_LOCK(tq);
682 	while ((tq->tq_flags & TQ_FLAGS_ACTIVE) != 0) {
683 		taskqueue_run_locked(tq);
684 		/*
685 		 * Because taskqueue_run() can drop tq_mutex, we need to
686 		 * check if the TQ_FLAGS_ACTIVE flag wasn't removed in the
687 		 * meantime, which means we missed a wakeup.
688 		 */
689 		if ((tq->tq_flags & TQ_FLAGS_ACTIVE) == 0)
690 			break;
691 		TQ_SLEEP(tq, tq, &tq->tq_mutex, 0, "-", 0);
692 	}
693 	taskqueue_run_locked(tq);
694 
695 	/*
696 	 * This thread is on its way out, so just drop the lock temporarily
697 	 * in order to call the shutdown callback.  This allows the callback
698 	 * to look at the taskqueue, even just before it dies.
699 	 */
700 	TQ_UNLOCK(tq);
701 	taskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_SHUTDOWN);
702 	TQ_LOCK(tq);
703 
704 	/* rendezvous with thread that asked us to terminate */
705 	tq->tq_tcount--;
706 	wakeup_one(tq->tq_threads);
707 	TQ_UNLOCK(tq);
708 	kthread_exit();
709 }
710 
711 void
712 taskqueue_thread_enqueue(void *context)
713 {
714 	struct taskqueue **tqp, *tq;
715 
716 	tqp = context;
717 	tq = *tqp;
718 
719 	wakeup_one(tq);
720 }
721 
722 TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, NULL,
723 		 swi_add(NULL, "task queue", taskqueue_swi_run, NULL, SWI_TQ,
724 		     INTR_MPSAFE, &taskqueue_ih));
725 
726 TASKQUEUE_DEFINE(swi_giant, taskqueue_swi_giant_enqueue, NULL,
727 		 swi_add(NULL, "Giant taskq", taskqueue_swi_giant_run,
728 		     NULL, SWI_TQ_GIANT, 0, &taskqueue_giant_ih));
729 
730 TASKQUEUE_DEFINE_THREAD(thread);
731 
732 struct taskqueue *
733 taskqueue_create_fast(const char *name, int mflags,
734 		 taskqueue_enqueue_fn enqueue, void *context)
735 {
736 	return _taskqueue_create(name, mflags, enqueue, context,
737 			MTX_SPIN, "fast_taskqueue");
738 }
739 
740 static void	*taskqueue_fast_ih;
741 
742 static void
743 taskqueue_fast_enqueue(void *context)
744 {
745 	swi_sched(taskqueue_fast_ih, 0);
746 }
747 
748 static void
749 taskqueue_fast_run(void *dummy)
750 {
751 	taskqueue_run(taskqueue_fast);
752 }
753 
754 TASKQUEUE_FAST_DEFINE(fast, taskqueue_fast_enqueue, NULL,
755 	swi_add(NULL, "fast taskq", taskqueue_fast_run, NULL,
756 	SWI_TQ_FAST, INTR_MPSAFE, &taskqueue_fast_ih));
757 
758 int
759 taskqueue_member(struct taskqueue *queue, struct thread *td)
760 {
761 	int i, j, ret = 0;
762 
763 	for (i = 0, j = 0; ; i++) {
764 		if (queue->tq_threads[i] == NULL)
765 			continue;
766 		if (queue->tq_threads[i] == td) {
767 			ret = 1;
768 			break;
769 		}
770 		if (++j >= queue->tq_tcount)
771 			break;
772 	}
773 	return (ret);
774 }
775