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: stable/10/sys/kern/subr_taskqueue.c 315268 2017-03-14 16:00:33Z hselasky $");
29
30#include <sys/param.h>
31#include <sys/systm.h>
32#include <sys/bus.h>
33#include <sys/interrupt.h>
34#include <sys/kernel.h>
35#include <sys/kthread.h>
36#include <sys/limits.h>
37#include <sys/lock.h>
38#include <sys/malloc.h>
39#include <sys/mutex.h>
40#include <sys/proc.h>
41#include <sys/sched.h>
42#include <sys/taskqueue.h>
43#include <sys/unistd.h>
44#include <machine/stdarg.h>
45
46static MALLOC_DEFINE(M_TASKQUEUE, "taskqueue", "Task Queues");
47static void	*taskqueue_giant_ih;
48static void	*taskqueue_ih;
49static void	 taskqueue_fast_enqueue(void *);
50static void	 taskqueue_swi_enqueue(void *);
51static void	 taskqueue_swi_giant_enqueue(void *);
52
53struct taskqueue_busy {
54	struct task	*tb_running;
55	TAILQ_ENTRY(taskqueue_busy) tb_link;
56};
57
58struct taskqueue {
59	STAILQ_HEAD(, task)	tq_queue;
60	taskqueue_enqueue_fn	tq_enqueue;
61	void			*tq_context;
62	TAILQ_HEAD(, taskqueue_busy) tq_active;
63	struct mtx		tq_mutex;
64	struct thread		**tq_threads;
65	int			tq_tcount;
66	int			tq_spin;
67	int			tq_flags;
68	int			tq_callouts;
69	taskqueue_callback_fn	tq_callbacks[TASKQUEUE_NUM_CALLBACKS];
70	void			*tq_cb_contexts[TASKQUEUE_NUM_CALLBACKS];
71};
72
73#define	TQ_FLAGS_ACTIVE		(1 << 0)
74#define	TQ_FLAGS_BLOCKED	(1 << 1)
75#define	TQ_FLAGS_UNLOCKED_ENQUEUE	(1 << 2)
76
77#define	DT_CALLOUT_ARMED	(1 << 0)
78#define	DT_DRAIN_IN_PROGRESS	(1 << 1)
79
80#define	TQ_LOCK(tq)							\
81	do {								\
82		if ((tq)->tq_spin)					\
83			mtx_lock_spin(&(tq)->tq_mutex);			\
84		else							\
85			mtx_lock(&(tq)->tq_mutex);			\
86	} while (0)
87#define	TQ_ASSERT_LOCKED(tq)	mtx_assert(&(tq)->tq_mutex, MA_OWNED)
88
89#define	TQ_UNLOCK(tq)							\
90	do {								\
91		if ((tq)->tq_spin)					\
92			mtx_unlock_spin(&(tq)->tq_mutex);		\
93		else							\
94			mtx_unlock(&(tq)->tq_mutex);			\
95	} while (0)
96#define	TQ_ASSERT_UNLOCKED(tq)	mtx_assert(&(tq)->tq_mutex, MA_NOTOWNED)
97
98void
99_timeout_task_init(struct taskqueue *queue, struct timeout_task *timeout_task,
100    int priority, task_fn_t func, void *context)
101{
102
103	TASK_INIT(&timeout_task->t, priority, func, context);
104	callout_init_mtx(&timeout_task->c, &queue->tq_mutex,
105	    CALLOUT_RETURNUNLOCKED);
106	timeout_task->q = queue;
107	timeout_task->f = 0;
108}
109
110static __inline int
111TQ_SLEEP(struct taskqueue *tq, void *p, struct mtx *m, int pri, const char *wm,
112    int t)
113{
114	if (tq->tq_spin)
115		return (msleep_spin(p, m, wm, t));
116	return (msleep(p, m, pri, wm, t));
117}
118
119static struct taskqueue *
120_taskqueue_create(const char *name __unused, int mflags,
121		 taskqueue_enqueue_fn enqueue, void *context,
122		 int mtxflags, const char *mtxname)
123{
124	struct taskqueue *queue;
125
126	queue = malloc(sizeof(struct taskqueue), M_TASKQUEUE, mflags | M_ZERO);
127	if (!queue)
128		return NULL;
129
130	STAILQ_INIT(&queue->tq_queue);
131	TAILQ_INIT(&queue->tq_active);
132	queue->tq_enqueue = enqueue;
133	queue->tq_context = context;
134	queue->tq_spin = (mtxflags & MTX_SPIN) != 0;
135	queue->tq_flags |= TQ_FLAGS_ACTIVE;
136	if (enqueue == taskqueue_fast_enqueue ||
137	    enqueue == taskqueue_swi_enqueue ||
138	    enqueue == taskqueue_swi_giant_enqueue ||
139	    enqueue == taskqueue_thread_enqueue)
140		queue->tq_flags |= TQ_FLAGS_UNLOCKED_ENQUEUE;
141	mtx_init(&queue->tq_mutex, mtxname, NULL, mtxflags);
142
143	return queue;
144}
145
146struct taskqueue *
147taskqueue_create(const char *name, int mflags,
148		 taskqueue_enqueue_fn enqueue, void *context)
149{
150	return _taskqueue_create(name, mflags, enqueue, context,
151			MTX_DEF, "taskqueue");
152}
153
154void
155taskqueue_set_callback(struct taskqueue *queue,
156    enum taskqueue_callback_type cb_type, taskqueue_callback_fn callback,
157    void *context)
158{
159
160	KASSERT(((cb_type >= TASKQUEUE_CALLBACK_TYPE_MIN) &&
161	    (cb_type <= TASKQUEUE_CALLBACK_TYPE_MAX)),
162	    ("Callback type %d not valid, must be %d-%d", cb_type,
163	    TASKQUEUE_CALLBACK_TYPE_MIN, TASKQUEUE_CALLBACK_TYPE_MAX));
164	KASSERT((queue->tq_callbacks[cb_type] == NULL),
165	    ("Re-initialization of taskqueue callback?"));
166
167	queue->tq_callbacks[cb_type] = callback;
168	queue->tq_cb_contexts[cb_type] = context;
169}
170
171/*
172 * Signal a taskqueue thread to terminate.
173 */
174static void
175taskqueue_terminate(struct thread **pp, struct taskqueue *tq)
176{
177
178	while (tq->tq_tcount > 0 || tq->tq_callouts > 0) {
179		wakeup(tq);
180		TQ_SLEEP(tq, pp, &tq->tq_mutex, PWAIT, "taskqueue_destroy", 0);
181	}
182}
183
184void
185taskqueue_free(struct taskqueue *queue)
186{
187
188	TQ_LOCK(queue);
189	queue->tq_flags &= ~TQ_FLAGS_ACTIVE;
190	taskqueue_terminate(queue->tq_threads, queue);
191	KASSERT(TAILQ_EMPTY(&queue->tq_active), ("Tasks still running?"));
192	KASSERT(queue->tq_callouts == 0, ("Armed timeout tasks"));
193	mtx_destroy(&queue->tq_mutex);
194	free(queue->tq_threads, M_TASKQUEUE);
195	free(queue, M_TASKQUEUE);
196}
197
198static int
199taskqueue_enqueue_locked(struct taskqueue *queue, struct task *task)
200{
201	struct task *ins;
202	struct task *prev;
203
204	/*
205	 * Count multiple enqueues.
206	 */
207	if (task->ta_pending) {
208		if (task->ta_pending < USHRT_MAX)
209			task->ta_pending++;
210		TQ_UNLOCK(queue);
211		return (0);
212	}
213
214	/*
215	 * Optimise the case when all tasks have the same priority.
216	 */
217	prev = STAILQ_LAST(&queue->tq_queue, task, ta_link);
218	if (!prev || prev->ta_priority >= task->ta_priority) {
219		STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link);
220	} else {
221		prev = NULL;
222		for (ins = STAILQ_FIRST(&queue->tq_queue); ins;
223		     prev = ins, ins = STAILQ_NEXT(ins, ta_link))
224			if (ins->ta_priority < task->ta_priority)
225				break;
226
227		if (prev)
228			STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link);
229		else
230			STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link);
231	}
232
233	task->ta_pending = 1;
234	if ((queue->tq_flags & TQ_FLAGS_UNLOCKED_ENQUEUE) != 0)
235		TQ_UNLOCK(queue);
236	if ((queue->tq_flags & TQ_FLAGS_BLOCKED) == 0)
237		queue->tq_enqueue(queue->tq_context);
238	if ((queue->tq_flags & TQ_FLAGS_UNLOCKED_ENQUEUE) == 0)
239		TQ_UNLOCK(queue);
240
241	/* Return with lock released. */
242	return (0);
243}
244int
245taskqueue_enqueue(struct taskqueue *queue, struct task *task)
246{
247	int res;
248
249	TQ_LOCK(queue);
250	res = taskqueue_enqueue_locked(queue, task);
251	/* The lock is released inside. */
252
253	return (res);
254}
255
256static void
257taskqueue_timeout_func(void *arg)
258{
259	struct taskqueue *queue;
260	struct timeout_task *timeout_task;
261
262	timeout_task = arg;
263	queue = timeout_task->q;
264	KASSERT((timeout_task->f & DT_CALLOUT_ARMED) != 0, ("Stray timeout"));
265	timeout_task->f &= ~DT_CALLOUT_ARMED;
266	queue->tq_callouts--;
267	taskqueue_enqueue_locked(timeout_task->q, &timeout_task->t);
268	/* The lock is released inside. */
269}
270
271int
272taskqueue_enqueue_timeout(struct taskqueue *queue,
273    struct timeout_task *timeout_task, int ticks)
274{
275	int res;
276
277	TQ_LOCK(queue);
278	KASSERT(timeout_task->q == NULL || timeout_task->q == queue,
279	    ("Migrated queue"));
280	KASSERT(!queue->tq_spin, ("Timeout for spin-queue"));
281	timeout_task->q = queue;
282	res = timeout_task->t.ta_pending;
283	if (timeout_task->f & DT_DRAIN_IN_PROGRESS) {
284		/* Do nothing */
285		TQ_UNLOCK(queue);
286		res = -1;
287	} else if (ticks == 0) {
288		taskqueue_enqueue_locked(queue, &timeout_task->t);
289		/* The lock is released inside. */
290	} else {
291		if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
292			res++;
293		} else {
294			queue->tq_callouts++;
295			timeout_task->f |= DT_CALLOUT_ARMED;
296			if (ticks < 0)
297				ticks = -ticks; /* Ignore overflow. */
298		}
299		if (ticks > 0) {
300			callout_reset(&timeout_task->c, ticks,
301			    taskqueue_timeout_func, timeout_task);
302		}
303		TQ_UNLOCK(queue);
304	}
305	return (res);
306}
307
308static void
309taskqueue_drain_running(struct taskqueue *queue)
310{
311
312	while (!TAILQ_EMPTY(&queue->tq_active))
313		TQ_SLEEP(queue, &queue->tq_active, &queue->tq_mutex,
314		    PWAIT, "-", 0);
315}
316
317void
318taskqueue_block(struct taskqueue *queue)
319{
320
321	TQ_LOCK(queue);
322	queue->tq_flags |= TQ_FLAGS_BLOCKED;
323	TQ_UNLOCK(queue);
324}
325
326void
327taskqueue_unblock(struct taskqueue *queue)
328{
329
330	TQ_LOCK(queue);
331	queue->tq_flags &= ~TQ_FLAGS_BLOCKED;
332	if (!STAILQ_EMPTY(&queue->tq_queue))
333		queue->tq_enqueue(queue->tq_context);
334	TQ_UNLOCK(queue);
335}
336
337static void
338taskqueue_run_locked(struct taskqueue *queue)
339{
340	struct taskqueue_busy tb;
341	struct task *task;
342	int pending;
343
344	TQ_ASSERT_LOCKED(queue);
345	tb.tb_running = NULL;
346	TAILQ_INSERT_TAIL(&queue->tq_active, &tb, tb_link);
347
348	while (STAILQ_FIRST(&queue->tq_queue)) {
349		/*
350		 * Carefully remove the first task from the queue and
351		 * zero its pending count.
352		 */
353		task = STAILQ_FIRST(&queue->tq_queue);
354		STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link);
355		pending = task->ta_pending;
356		task->ta_pending = 0;
357		tb.tb_running = task;
358		TQ_UNLOCK(queue);
359
360		task->ta_func(task->ta_context, pending);
361
362		TQ_LOCK(queue);
363		tb.tb_running = NULL;
364		wakeup(task);
365	}
366	TAILQ_REMOVE(&queue->tq_active, &tb, tb_link);
367	if (TAILQ_EMPTY(&queue->tq_active))
368		wakeup(&queue->tq_active);
369}
370
371void
372taskqueue_run(struct taskqueue *queue)
373{
374
375	TQ_LOCK(queue);
376	taskqueue_run_locked(queue);
377	TQ_UNLOCK(queue);
378}
379
380static int
381task_is_running(struct taskqueue *queue, struct task *task)
382{
383	struct taskqueue_busy *tb;
384
385	TQ_ASSERT_LOCKED(queue);
386	TAILQ_FOREACH(tb, &queue->tq_active, tb_link) {
387		if (tb->tb_running == task)
388			return (1);
389	}
390	return (0);
391}
392
393/*
394 * Only use this function in single threaded contexts. It returns
395 * non-zero if the given task is either pending or running. Else the
396 * task is idle and can be queued again or freed.
397 */
398int
399taskqueue_poll_is_busy(struct taskqueue *queue, struct task *task)
400{
401	int retval;
402
403	TQ_LOCK(queue);
404	retval = task->ta_pending > 0 || task_is_running(queue, task);
405	TQ_UNLOCK(queue);
406
407	return (retval);
408}
409
410static int
411taskqueue_cancel_locked(struct taskqueue *queue, struct task *task,
412    u_int *pendp)
413{
414
415	if (task->ta_pending > 0)
416		STAILQ_REMOVE(&queue->tq_queue, task, task, ta_link);
417	if (pendp != NULL)
418		*pendp = task->ta_pending;
419	task->ta_pending = 0;
420	return (task_is_running(queue, task) ? EBUSY : 0);
421}
422
423int
424taskqueue_cancel(struct taskqueue *queue, struct task *task, u_int *pendp)
425{
426	int error;
427
428	TQ_LOCK(queue);
429	error = taskqueue_cancel_locked(queue, task, pendp);
430	TQ_UNLOCK(queue);
431
432	return (error);
433}
434
435int
436taskqueue_cancel_timeout(struct taskqueue *queue,
437    struct timeout_task *timeout_task, u_int *pendp)
438{
439	u_int pending, pending1;
440	int error;
441
442	TQ_LOCK(queue);
443	pending = !!callout_stop(&timeout_task->c);
444	error = taskqueue_cancel_locked(queue, &timeout_task->t, &pending1);
445	if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
446		timeout_task->f &= ~DT_CALLOUT_ARMED;
447		queue->tq_callouts--;
448	}
449	TQ_UNLOCK(queue);
450
451	if (pendp != NULL)
452		*pendp = pending + pending1;
453	return (error);
454}
455
456void
457taskqueue_drain(struct taskqueue *queue, struct task *task)
458{
459
460	if (!queue->tq_spin)
461		WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
462
463	TQ_LOCK(queue);
464	while (task->ta_pending != 0 || task_is_running(queue, task))
465		TQ_SLEEP(queue, task, &queue->tq_mutex, PWAIT, "-", 0);
466	TQ_UNLOCK(queue);
467}
468
469void
470taskqueue_drain_all(struct taskqueue *queue)
471{
472	struct task *task;
473
474	if (!queue->tq_spin)
475		WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
476
477	TQ_LOCK(queue);
478	task = STAILQ_LAST(&queue->tq_queue, task, ta_link);
479	while (task != NULL && task->ta_pending != 0) {
480		struct task *oldtask;
481		TQ_SLEEP(queue, task, &queue->tq_mutex, PWAIT, "-", 0);
482		/*
483		 * While we were asleeep the last entry may have been freed.
484		 * We need to check if it's still even in the queue.
485		 * Not perfect, but it's better than referencing bad memory.
486		 * first guess is the current 'end of queue' but if a new
487		 * item has been added we need to take the expensive path
488		 * Better fix in 11.
489		 */
490		oldtask = task;
491		if (oldtask !=
492		    (task = STAILQ_LAST(&queue->tq_queue, task, ta_link))) {
493			STAILQ_FOREACH(task, &queue->tq_queue, ta_link) {
494				if (task == oldtask)
495					break;
496			}
497		}
498	}
499	taskqueue_drain_running(queue);
500	KASSERT(STAILQ_EMPTY(&queue->tq_queue),
501	    ("taskqueue queue is not empty after draining"));
502	TQ_UNLOCK(queue);
503}
504
505void
506taskqueue_drain_timeout(struct taskqueue *queue,
507    struct timeout_task *timeout_task)
508{
509
510	/*
511	 * Set flag to prevent timer from re-starting during drain:
512	 */
513	TQ_LOCK(queue);
514	KASSERT((timeout_task->f & DT_DRAIN_IN_PROGRESS) == 0,
515	    ("Drain already in progress"));
516	timeout_task->f |= DT_DRAIN_IN_PROGRESS;
517	TQ_UNLOCK(queue);
518
519	callout_drain(&timeout_task->c);
520	taskqueue_drain(queue, &timeout_task->t);
521
522	/*
523	 * Clear flag to allow timer to re-start:
524	 */
525	TQ_LOCK(queue);
526	timeout_task->f &= ~DT_DRAIN_IN_PROGRESS;
527	TQ_UNLOCK(queue);
528}
529
530static void
531taskqueue_swi_enqueue(void *context)
532{
533	swi_sched(taskqueue_ih, 0);
534}
535
536static void
537taskqueue_swi_run(void *dummy)
538{
539	taskqueue_run(taskqueue_swi);
540}
541
542static void
543taskqueue_swi_giant_enqueue(void *context)
544{
545	swi_sched(taskqueue_giant_ih, 0);
546}
547
548static void
549taskqueue_swi_giant_run(void *dummy)
550{
551	taskqueue_run(taskqueue_swi_giant);
552}
553
554int
555taskqueue_start_threads(struct taskqueue **tqp, int count, int pri,
556			const char *name, ...)
557{
558	va_list ap;
559	struct thread *td;
560	struct taskqueue *tq;
561	int i, error;
562	char ktname[MAXCOMLEN + 1];
563
564	if (count <= 0)
565		return (EINVAL);
566
567	tq = *tqp;
568
569	va_start(ap, name);
570	vsnprintf(ktname, sizeof(ktname), name, ap);
571	va_end(ap);
572
573	tq->tq_threads = malloc(sizeof(struct thread *) * count, M_TASKQUEUE,
574	    M_NOWAIT | M_ZERO);
575	if (tq->tq_threads == NULL) {
576		printf("%s: no memory for %s threads\n", __func__, ktname);
577		return (ENOMEM);
578	}
579
580	for (i = 0; i < count; i++) {
581		if (count == 1)
582			error = kthread_add(taskqueue_thread_loop, tqp, NULL,
583			    &tq->tq_threads[i], RFSTOPPED, 0, "%s", ktname);
584		else
585			error = kthread_add(taskqueue_thread_loop, tqp, NULL,
586			    &tq->tq_threads[i], RFSTOPPED, 0,
587			    "%s_%d", ktname, i);
588		if (error) {
589			/* should be ok to continue, taskqueue_free will dtrt */
590			printf("%s: kthread_add(%s): error %d", __func__,
591			    ktname, error);
592			tq->tq_threads[i] = NULL;		/* paranoid */
593		} else
594			tq->tq_tcount++;
595	}
596	for (i = 0; i < count; i++) {
597		if (tq->tq_threads[i] == NULL)
598			continue;
599		td = tq->tq_threads[i];
600		thread_lock(td);
601		sched_prio(td, pri);
602		sched_add(td, SRQ_BORING);
603		thread_unlock(td);
604	}
605
606	return (0);
607}
608
609static inline void
610taskqueue_run_callback(struct taskqueue *tq,
611    enum taskqueue_callback_type cb_type)
612{
613	taskqueue_callback_fn tq_callback;
614
615	TQ_ASSERT_UNLOCKED(tq);
616	tq_callback = tq->tq_callbacks[cb_type];
617	if (tq_callback != NULL)
618		tq_callback(tq->tq_cb_contexts[cb_type]);
619}
620
621void
622taskqueue_thread_loop(void *arg)
623{
624	struct taskqueue **tqp, *tq;
625
626	tqp = arg;
627	tq = *tqp;
628	taskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_INIT);
629	TQ_LOCK(tq);
630	while ((tq->tq_flags & TQ_FLAGS_ACTIVE) != 0) {
631		taskqueue_run_locked(tq);
632		/*
633		 * Because taskqueue_run() can drop tq_mutex, we need to
634		 * check if the TQ_FLAGS_ACTIVE flag wasn't removed in the
635		 * meantime, which means we missed a wakeup.
636		 */
637		if ((tq->tq_flags & TQ_FLAGS_ACTIVE) == 0)
638			break;
639		TQ_SLEEP(tq, tq, &tq->tq_mutex, 0, "-", 0);
640	}
641	taskqueue_run_locked(tq);
642
643	/*
644	 * This thread is on its way out, so just drop the lock temporarily
645	 * in order to call the shutdown callback.  This allows the callback
646	 * to look at the taskqueue, even just before it dies.
647	 */
648	TQ_UNLOCK(tq);
649	taskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_SHUTDOWN);
650	TQ_LOCK(tq);
651
652	/* rendezvous with thread that asked us to terminate */
653	tq->tq_tcount--;
654	wakeup_one(tq->tq_threads);
655	TQ_UNLOCK(tq);
656	kthread_exit();
657}
658
659void
660taskqueue_thread_enqueue(void *context)
661{
662	struct taskqueue **tqp, *tq;
663
664	tqp = context;
665	tq = *tqp;
666
667	wakeup_one(tq);
668}
669
670TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, NULL,
671		 swi_add(NULL, "task queue", taskqueue_swi_run, NULL, SWI_TQ,
672		     INTR_MPSAFE, &taskqueue_ih));
673
674TASKQUEUE_DEFINE(swi_giant, taskqueue_swi_giant_enqueue, NULL,
675		 swi_add(NULL, "Giant taskq", taskqueue_swi_giant_run,
676		     NULL, SWI_TQ_GIANT, 0, &taskqueue_giant_ih));
677
678TASKQUEUE_DEFINE_THREAD(thread);
679
680struct taskqueue *
681taskqueue_create_fast(const char *name, int mflags,
682		 taskqueue_enqueue_fn enqueue, void *context)
683{
684	return _taskqueue_create(name, mflags, enqueue, context,
685			MTX_SPIN, "fast_taskqueue");
686}
687
688/* NB: for backwards compatibility */
689int
690taskqueue_enqueue_fast(struct taskqueue *queue, struct task *task)
691{
692	return taskqueue_enqueue(queue, task);
693}
694
695static void	*taskqueue_fast_ih;
696
697static void
698taskqueue_fast_enqueue(void *context)
699{
700	swi_sched(taskqueue_fast_ih, 0);
701}
702
703static void
704taskqueue_fast_run(void *dummy)
705{
706	taskqueue_run(taskqueue_fast);
707}
708
709TASKQUEUE_FAST_DEFINE(fast, taskqueue_fast_enqueue, NULL,
710	swi_add(NULL, "fast taskq", taskqueue_fast_run, NULL,
711	SWI_TQ_FAST, INTR_MPSAFE, &taskqueue_fast_ih));
712
713int
714taskqueue_member(struct taskqueue *queue, struct thread *td)
715{
716	int i, j, ret = 0;
717
718	for (i = 0, j = 0; ; i++) {
719		if (queue->tq_threads[i] == NULL)
720			continue;
721		if (queue->tq_threads[i] == td) {
722			ret = 1;
723			break;
724		}
725		if (++j >= queue->tq_tcount)
726			break;
727	}
728	return (ret);
729}
730