2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright (c) 2000 Doug Rabson
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
32 #include <sys/param.h>
33 #include <sys/systm.h>
35 #include <sys/cpuset.h>
36 #include <sys/interrupt.h>
37 #include <sys/kernel.h>
38 #include <sys/kthread.h>
39 #include <sys/libkern.h>
40 #include <sys/limits.h>
42 #include <sys/malloc.h>
43 #include <sys/mutex.h>
45 #include <sys/sched.h>
47 #include <sys/taskqueue.h>
48 #include <sys/unistd.h>
49 #include <machine/stdarg.h>
51 static MALLOC_DEFINE(M_TASKQUEUE, "taskqueue", "Task Queues");
52 static void *taskqueue_giant_ih;
53 static void *taskqueue_ih;
54 static void taskqueue_fast_enqueue(void *);
55 static void taskqueue_swi_enqueue(void *);
56 static void taskqueue_swi_giant_enqueue(void *);
58 struct taskqueue_busy {
59 struct task *tb_running;
60 TAILQ_ENTRY(taskqueue_busy) tb_link;
63 struct task * const TB_DRAIN_WAITER = (struct task *)0x1;
66 STAILQ_HEAD(, task) tq_queue;
67 taskqueue_enqueue_fn tq_enqueue;
70 TAILQ_HEAD(, taskqueue_busy) tq_active;
72 struct thread **tq_threads;
77 taskqueue_callback_fn tq_callbacks[TASKQUEUE_NUM_CALLBACKS];
78 void *tq_cb_contexts[TASKQUEUE_NUM_CALLBACKS];
81 #define TQ_FLAGS_ACTIVE (1 << 0)
82 #define TQ_FLAGS_BLOCKED (1 << 1)
83 #define TQ_FLAGS_UNLOCKED_ENQUEUE (1 << 2)
85 #define DT_CALLOUT_ARMED (1 << 0)
86 #define DT_DRAIN_IN_PROGRESS (1 << 1)
91 mtx_lock_spin(&(tq)->tq_mutex); \
93 mtx_lock(&(tq)->tq_mutex); \
95 #define TQ_ASSERT_LOCKED(tq) mtx_assert(&(tq)->tq_mutex, MA_OWNED)
97 #define TQ_UNLOCK(tq) \
100 mtx_unlock_spin(&(tq)->tq_mutex); \
102 mtx_unlock(&(tq)->tq_mutex); \
104 #define TQ_ASSERT_UNLOCKED(tq) mtx_assert(&(tq)->tq_mutex, MA_NOTOWNED)
107 _timeout_task_init(struct taskqueue *queue, struct timeout_task *timeout_task,
108 int priority, task_fn_t func, void *context)
111 TASK_INIT(&timeout_task->t, priority, func, context);
112 callout_init_mtx(&timeout_task->c, &queue->tq_mutex,
113 CALLOUT_RETURNUNLOCKED);
114 timeout_task->q = queue;
119 TQ_SLEEP(struct taskqueue *tq, void *p, struct mtx *m, int pri, const char *wm,
123 return (msleep_spin(p, m, wm, t));
124 return (msleep(p, m, pri, wm, t));
127 static struct taskqueue *
128 _taskqueue_create(const char *name, int mflags,
129 taskqueue_enqueue_fn enqueue, void *context,
130 int mtxflags, const char *mtxname __unused)
132 struct taskqueue *queue;
135 tq_name = malloc(TASKQUEUE_NAMELEN, M_TASKQUEUE, mflags | M_ZERO);
139 queue = malloc(sizeof(struct taskqueue), M_TASKQUEUE, mflags | M_ZERO);
141 free(tq_name, M_TASKQUEUE);
145 snprintf(tq_name, TASKQUEUE_NAMELEN, "%s", (name) ? name : "taskqueue");
147 STAILQ_INIT(&queue->tq_queue);
148 TAILQ_INIT(&queue->tq_active);
149 queue->tq_enqueue = enqueue;
150 queue->tq_context = context;
151 queue->tq_name = tq_name;
152 queue->tq_spin = (mtxflags & MTX_SPIN) != 0;
153 queue->tq_flags |= TQ_FLAGS_ACTIVE;
154 if (enqueue == taskqueue_fast_enqueue ||
155 enqueue == taskqueue_swi_enqueue ||
156 enqueue == taskqueue_swi_giant_enqueue ||
157 enqueue == taskqueue_thread_enqueue)
158 queue->tq_flags |= TQ_FLAGS_UNLOCKED_ENQUEUE;
159 mtx_init(&queue->tq_mutex, tq_name, NULL, mtxflags);
165 taskqueue_create(const char *name, int mflags,
166 taskqueue_enqueue_fn enqueue, void *context)
169 return _taskqueue_create(name, mflags, enqueue, context,
174 taskqueue_set_callback(struct taskqueue *queue,
175 enum taskqueue_callback_type cb_type, taskqueue_callback_fn callback,
179 KASSERT(((cb_type >= TASKQUEUE_CALLBACK_TYPE_MIN) &&
180 (cb_type <= TASKQUEUE_CALLBACK_TYPE_MAX)),
181 ("Callback type %d not valid, must be %d-%d", cb_type,
182 TASKQUEUE_CALLBACK_TYPE_MIN, TASKQUEUE_CALLBACK_TYPE_MAX));
183 KASSERT((queue->tq_callbacks[cb_type] == NULL),
184 ("Re-initialization of taskqueue callback?"));
186 queue->tq_callbacks[cb_type] = callback;
187 queue->tq_cb_contexts[cb_type] = context;
191 * Signal a taskqueue thread to terminate.
194 taskqueue_terminate(struct thread **pp, struct taskqueue *tq)
197 while (tq->tq_tcount > 0 || tq->tq_callouts > 0) {
199 TQ_SLEEP(tq, pp, &tq->tq_mutex, PWAIT, "taskqueue_destroy", 0);
204 taskqueue_free(struct taskqueue *queue)
208 queue->tq_flags &= ~TQ_FLAGS_ACTIVE;
209 taskqueue_terminate(queue->tq_threads, queue);
210 KASSERT(TAILQ_EMPTY(&queue->tq_active), ("Tasks still running?"));
211 KASSERT(queue->tq_callouts == 0, ("Armed timeout tasks"));
212 mtx_destroy(&queue->tq_mutex);
213 free(queue->tq_threads, M_TASKQUEUE);
214 free(queue->tq_name, M_TASKQUEUE);
215 free(queue, M_TASKQUEUE);
219 taskqueue_enqueue_locked(struct taskqueue *queue, struct task *task)
224 KASSERT(task->ta_func != NULL, ("enqueueing task with NULL func"));
226 * Count multiple enqueues.
228 if (task->ta_pending) {
229 if (task->ta_pending < USHRT_MAX)
236 * Optimise the case when all tasks have the same priority.
238 prev = STAILQ_LAST(&queue->tq_queue, task, ta_link);
239 if (!prev || prev->ta_priority >= task->ta_priority) {
240 STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link);
243 for (ins = STAILQ_FIRST(&queue->tq_queue); ins;
244 prev = ins, ins = STAILQ_NEXT(ins, ta_link))
245 if (ins->ta_priority < task->ta_priority)
249 STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link);
251 STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link);
254 task->ta_pending = 1;
255 if ((queue->tq_flags & TQ_FLAGS_UNLOCKED_ENQUEUE) != 0)
257 if ((queue->tq_flags & TQ_FLAGS_BLOCKED) == 0)
258 queue->tq_enqueue(queue->tq_context);
259 if ((queue->tq_flags & TQ_FLAGS_UNLOCKED_ENQUEUE) == 0)
262 /* Return with lock released. */
267 taskqueue_enqueue(struct taskqueue *queue, struct task *task)
272 res = taskqueue_enqueue_locked(queue, task);
273 /* The lock is released inside. */
279 taskqueue_timeout_func(void *arg)
281 struct taskqueue *queue;
282 struct timeout_task *timeout_task;
285 queue = timeout_task->q;
286 KASSERT((timeout_task->f & DT_CALLOUT_ARMED) != 0, ("Stray timeout"));
287 timeout_task->f &= ~DT_CALLOUT_ARMED;
288 queue->tq_callouts--;
289 taskqueue_enqueue_locked(timeout_task->q, &timeout_task->t);
290 /* The lock is released inside. */
294 taskqueue_enqueue_timeout_sbt(struct taskqueue *queue,
295 struct timeout_task *timeout_task, sbintime_t sbt, sbintime_t pr, int flags)
300 KASSERT(timeout_task->q == NULL || timeout_task->q == queue,
302 KASSERT(!queue->tq_spin, ("Timeout for spin-queue"));
303 timeout_task->q = queue;
304 res = timeout_task->t.ta_pending;
305 if (timeout_task->f & DT_DRAIN_IN_PROGRESS) {
309 } else if (sbt == 0) {
310 taskqueue_enqueue_locked(queue, &timeout_task->t);
311 /* The lock is released inside. */
313 if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
316 queue->tq_callouts++;
317 timeout_task->f |= DT_CALLOUT_ARMED;
319 sbt = -sbt; /* Ignore overflow. */
322 callout_reset_sbt(&timeout_task->c, sbt, pr,
323 taskqueue_timeout_func, timeout_task, flags);
331 taskqueue_enqueue_timeout(struct taskqueue *queue,
332 struct timeout_task *ttask, int ticks)
335 return (taskqueue_enqueue_timeout_sbt(queue, ttask, ticks * tick_sbt,
340 taskqueue_task_nop_fn(void *context, int pending)
345 * Block until all currently queued tasks in this taskqueue
346 * have begun execution. Tasks queued during execution of
347 * this function are ignored.
350 taskqueue_drain_tq_queue(struct taskqueue *queue)
352 struct task t_barrier;
354 if (STAILQ_EMPTY(&queue->tq_queue))
358 * Enqueue our barrier after all current tasks, but with
359 * the highest priority so that newly queued tasks cannot
360 * pass it. Because of the high priority, we can not use
361 * taskqueue_enqueue_locked directly (which drops the lock
362 * anyway) so just insert it at tail while we have the
365 TASK_INIT(&t_barrier, USHRT_MAX, taskqueue_task_nop_fn, &t_barrier);
366 STAILQ_INSERT_TAIL(&queue->tq_queue, &t_barrier, ta_link);
367 t_barrier.ta_pending = 1;
370 * Once the barrier has executed, all previously queued tasks
371 * have completed or are currently executing.
373 while (t_barrier.ta_pending != 0)
374 TQ_SLEEP(queue, &t_barrier, &queue->tq_mutex, PWAIT, "-", 0);
379 * Block until all currently executing tasks for this taskqueue
380 * complete. Tasks that begin execution during the execution
381 * of this function are ignored.
384 taskqueue_drain_tq_active(struct taskqueue *queue)
386 struct taskqueue_busy tb_marker, *tb_first;
388 if (TAILQ_EMPTY(&queue->tq_active))
391 /* Block taskq_terminate().*/
392 queue->tq_callouts++;
395 * Wait for all currently executing taskqueue threads
398 tb_marker.tb_running = TB_DRAIN_WAITER;
399 TAILQ_INSERT_TAIL(&queue->tq_active, &tb_marker, tb_link);
400 while (TAILQ_FIRST(&queue->tq_active) != &tb_marker)
401 TQ_SLEEP(queue, &tb_marker, &queue->tq_mutex, PWAIT, "-", 0);
402 TAILQ_REMOVE(&queue->tq_active, &tb_marker, tb_link);
405 * Wakeup any other drain waiter that happened to queue up
406 * without any intervening active thread.
408 tb_first = TAILQ_FIRST(&queue->tq_active);
409 if (tb_first != NULL && tb_first->tb_running == TB_DRAIN_WAITER)
412 /* Release taskqueue_terminate(). */
413 queue->tq_callouts--;
414 if ((queue->tq_flags & TQ_FLAGS_ACTIVE) == 0)
415 wakeup_one(queue->tq_threads);
420 taskqueue_block(struct taskqueue *queue)
424 queue->tq_flags |= TQ_FLAGS_BLOCKED;
429 taskqueue_unblock(struct taskqueue *queue)
433 queue->tq_flags &= ~TQ_FLAGS_BLOCKED;
434 if (!STAILQ_EMPTY(&queue->tq_queue))
435 queue->tq_enqueue(queue->tq_context);
440 taskqueue_run_locked(struct taskqueue *queue)
442 struct taskqueue_busy tb;
443 struct taskqueue_busy *tb_first;
447 KASSERT(queue != NULL, ("tq is NULL"));
448 TQ_ASSERT_LOCKED(queue);
449 tb.tb_running = NULL;
451 while (STAILQ_FIRST(&queue->tq_queue)) {
452 TAILQ_INSERT_TAIL(&queue->tq_active, &tb, tb_link);
455 * Carefully remove the first task from the queue and
456 * zero its pending count.
458 task = STAILQ_FIRST(&queue->tq_queue);
459 KASSERT(task != NULL, ("task is NULL"));
460 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link);
461 pending = task->ta_pending;
462 task->ta_pending = 0;
463 tb.tb_running = task;
466 KASSERT(task->ta_func != NULL, ("task->ta_func is NULL"));
467 task->ta_func(task->ta_context, pending);
470 tb.tb_running = NULL;
473 TAILQ_REMOVE(&queue->tq_active, &tb, tb_link);
474 tb_first = TAILQ_FIRST(&queue->tq_active);
475 if (tb_first != NULL &&
476 tb_first->tb_running == TB_DRAIN_WAITER)
482 taskqueue_run(struct taskqueue *queue)
486 taskqueue_run_locked(queue);
491 task_is_running(struct taskqueue *queue, struct task *task)
493 struct taskqueue_busy *tb;
495 TQ_ASSERT_LOCKED(queue);
496 TAILQ_FOREACH(tb, &queue->tq_active, tb_link) {
497 if (tb->tb_running == task)
504 * Only use this function in single threaded contexts. It returns
505 * non-zero if the given task is either pending or running. Else the
506 * task is idle and can be queued again or freed.
509 taskqueue_poll_is_busy(struct taskqueue *queue, struct task *task)
514 retval = task->ta_pending > 0 || task_is_running(queue, task);
521 taskqueue_cancel_locked(struct taskqueue *queue, struct task *task,
525 if (task->ta_pending > 0)
526 STAILQ_REMOVE(&queue->tq_queue, task, task, ta_link);
528 *pendp = task->ta_pending;
529 task->ta_pending = 0;
530 return (task_is_running(queue, task) ? EBUSY : 0);
534 taskqueue_cancel(struct taskqueue *queue, struct task *task, u_int *pendp)
539 error = taskqueue_cancel_locked(queue, task, pendp);
546 taskqueue_cancel_timeout(struct taskqueue *queue,
547 struct timeout_task *timeout_task, u_int *pendp)
549 u_int pending, pending1;
553 pending = !!(callout_stop(&timeout_task->c) > 0);
554 error = taskqueue_cancel_locked(queue, &timeout_task->t, &pending1);
555 if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
556 timeout_task->f &= ~DT_CALLOUT_ARMED;
557 queue->tq_callouts--;
562 *pendp = pending + pending1;
567 taskqueue_drain(struct taskqueue *queue, struct task *task)
571 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
574 while (task->ta_pending != 0 || task_is_running(queue, task))
575 TQ_SLEEP(queue, task, &queue->tq_mutex, PWAIT, "-", 0);
580 taskqueue_drain_all(struct taskqueue *queue)
584 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
587 (void)taskqueue_drain_tq_queue(queue);
588 (void)taskqueue_drain_tq_active(queue);
593 taskqueue_drain_timeout(struct taskqueue *queue,
594 struct timeout_task *timeout_task)
598 * Set flag to prevent timer from re-starting during drain:
601 KASSERT((timeout_task->f & DT_DRAIN_IN_PROGRESS) == 0,
602 ("Drain already in progress"));
603 timeout_task->f |= DT_DRAIN_IN_PROGRESS;
606 callout_drain(&timeout_task->c);
607 taskqueue_drain(queue, &timeout_task->t);
610 * Clear flag to allow timer to re-start:
613 timeout_task->f &= ~DT_DRAIN_IN_PROGRESS;
618 taskqueue_quiesce(struct taskqueue *queue)
624 ret = taskqueue_drain_tq_queue(queue);
626 ret = taskqueue_drain_tq_active(queue);
632 taskqueue_swi_enqueue(void *context)
634 swi_sched(taskqueue_ih, 0);
638 taskqueue_swi_run(void *dummy)
640 taskqueue_run(taskqueue_swi);
644 taskqueue_swi_giant_enqueue(void *context)
646 swi_sched(taskqueue_giant_ih, 0);
650 taskqueue_swi_giant_run(void *dummy)
652 taskqueue_run(taskqueue_swi_giant);
656 _taskqueue_start_threads(struct taskqueue **tqp, int count, int pri,
657 cpuset_t *mask, const char *name, va_list ap)
659 char ktname[MAXCOMLEN + 1];
661 struct taskqueue *tq;
667 vsnprintf(ktname, sizeof(ktname), name, ap);
670 tq->tq_threads = malloc(sizeof(struct thread *) * count, M_TASKQUEUE,
672 if (tq->tq_threads == NULL) {
673 printf("%s: no memory for %s threads\n", __func__, ktname);
677 for (i = 0; i < count; i++) {
679 error = kthread_add(taskqueue_thread_loop, tqp, NULL,
680 &tq->tq_threads[i], RFSTOPPED, 0, "%s", ktname);
682 error = kthread_add(taskqueue_thread_loop, tqp, NULL,
683 &tq->tq_threads[i], RFSTOPPED, 0,
686 /* should be ok to continue, taskqueue_free will dtrt */
687 printf("%s: kthread_add(%s): error %d", __func__,
689 tq->tq_threads[i] = NULL; /* paranoid */
693 if (tq->tq_tcount == 0) {
694 free(tq->tq_threads, M_TASKQUEUE);
695 tq->tq_threads = NULL;
698 for (i = 0; i < count; i++) {
699 if (tq->tq_threads[i] == NULL)
701 td = tq->tq_threads[i];
703 error = cpuset_setthread(td->td_tid, mask);
705 * Failing to pin is rarely an actual fatal error;
706 * it'll just affect performance.
709 printf("%s: curthread=%llu: can't pin; "
712 (unsigned long long) td->td_tid,
717 sched_add(td, SRQ_BORING);
725 taskqueue_start_threads(struct taskqueue **tqp, int count, int pri,
726 const char *name, ...)
732 error = _taskqueue_start_threads(tqp, count, pri, NULL, name, ap);
738 taskqueue_start_threads_cpuset(struct taskqueue **tqp, int count, int pri,
739 cpuset_t *mask, const char *name, ...)
745 error = _taskqueue_start_threads(tqp, count, pri, mask, name, ap);
751 taskqueue_run_callback(struct taskqueue *tq,
752 enum taskqueue_callback_type cb_type)
754 taskqueue_callback_fn tq_callback;
756 TQ_ASSERT_UNLOCKED(tq);
757 tq_callback = tq->tq_callbacks[cb_type];
758 if (tq_callback != NULL)
759 tq_callback(tq->tq_cb_contexts[cb_type]);
763 taskqueue_thread_loop(void *arg)
765 struct taskqueue **tqp, *tq;
769 taskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_INIT);
771 while ((tq->tq_flags & TQ_FLAGS_ACTIVE) != 0) {
773 taskqueue_run_locked(tq);
775 * Because taskqueue_run() can drop tq_mutex, we need to
776 * check if the TQ_FLAGS_ACTIVE flag wasn't removed in the
777 * meantime, which means we missed a wakeup.
779 if ((tq->tq_flags & TQ_FLAGS_ACTIVE) == 0)
781 TQ_SLEEP(tq, tq, &tq->tq_mutex, 0, "-", 0);
783 taskqueue_run_locked(tq);
785 * This thread is on its way out, so just drop the lock temporarily
786 * in order to call the shutdown callback. This allows the callback
787 * to look at the taskqueue, even just before it dies.
790 taskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_SHUTDOWN);
793 /* rendezvous with thread that asked us to terminate */
795 wakeup_one(tq->tq_threads);
801 taskqueue_thread_enqueue(void *context)
803 struct taskqueue **tqp, *tq;
810 TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, NULL,
811 swi_add(NULL, "task queue", taskqueue_swi_run, NULL, SWI_TQ,
812 INTR_MPSAFE, &taskqueue_ih));
814 TASKQUEUE_DEFINE(swi_giant, taskqueue_swi_giant_enqueue, NULL,
815 swi_add(NULL, "Giant taskq", taskqueue_swi_giant_run,
816 NULL, SWI_TQ_GIANT, 0, &taskqueue_giant_ih));
818 TASKQUEUE_DEFINE_THREAD(thread);
821 taskqueue_create_fast(const char *name, int mflags,
822 taskqueue_enqueue_fn enqueue, void *context)
824 return _taskqueue_create(name, mflags, enqueue, context,
825 MTX_SPIN, "fast_taskqueue");
828 static void *taskqueue_fast_ih;
831 taskqueue_fast_enqueue(void *context)
833 swi_sched(taskqueue_fast_ih, 0);
837 taskqueue_fast_run(void *dummy)
839 taskqueue_run(taskqueue_fast);
842 TASKQUEUE_FAST_DEFINE(fast, taskqueue_fast_enqueue, NULL,
843 swi_add(NULL, "fast taskq", taskqueue_fast_run, NULL,
844 SWI_TQ_FAST, INTR_MPSAFE, &taskqueue_fast_ih));
847 taskqueue_member(struct taskqueue *queue, struct thread *td)
851 for (i = 0, j = 0; ; i++) {
852 if (queue->tq_threads[i] == NULL)
854 if (queue->tq_threads[i] == td) {
858 if (++j >= queue->tq_tcount)