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source: rtems-libbsd/freebsd/sys/kern/subr_taskqueue.c @ 4a8f953

55-freebsd-126-freebsd-12

Last change on this file since 4a8f953 was 4a8f953, checked in by Kevin Kirspel <kevin-kirspel@…>, on 05/04/17 at 12:27:58
Updating FREEBSD for tty support
Property mode set to `100644`
File size: 21.1 KB

Line
1	#include <machine/rtems-bsd-kernel-space.h>
2
3	/*-
4	* Copyright (c) 2000 Doug Rabson
5	* All rights reserved.
6	*
7	* Redistribution and use in source and binary forms, with or without
8	* modification, are permitted provided that the following conditions
9	* are met:
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.
15	*
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
26	* SUCH DAMAGE.
27	*/
28
29	#include <sys/cdefs.h>
30	__FBSDID("$FreeBSD$");
31
32	#include <rtems/bsd/sys/param.h>
33	#include <sys/systm.h>
34	#include <sys/bus.h>
35	#include <rtems/bsd/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>
41	#include <rtems/bsd/sys/lock.h>
42	#include <sys/malloc.h>
43	#include <sys/mutex.h>
44	#include <sys/proc.h>
45	#include <sys/sched.h>
46	#include <sys/smp.h>
47	#include <sys/taskqueue.h>
48	#include <rtems/bsd/sys/unistd.h>
49	#include <machine/stdarg.h>
50
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 *);
57
58	struct taskqueue_busy {
59	struct task *tb_running;
60	TAILQ_ENTRY(taskqueue_busy) tb_link;
61	};
62
63	struct task * const TB_DRAIN_WAITER = (struct task *)0x1;
64
65	struct taskqueue {
66	STAILQ_HEAD(, task) tq_queue;
67	taskqueue_enqueue_fn tq_enqueue;
68	void *tq_context;
69	char *tq_name;
70	TAILQ_HEAD(, taskqueue_busy) tq_active;
71	struct mtx tq_mutex;
72	struct thread **tq_threads;
73	int tq_tcount;
74	#ifndef __rtems__
75	int tq_spin;
76	#endif /* __rtems__ */
77	int tq_flags;
78	int tq_callouts;
79	taskqueue_callback_fn tq_callbacks[TASKQUEUE_NUM_CALLBACKS];
80	void *tq_cb_contexts[TASKQUEUE_NUM_CALLBACKS];
81	};
82
83	#define TQ_FLAGS_ACTIVE (1 << 0)
84	#define TQ_FLAGS_BLOCKED (1 << 1)
85	#define TQ_FLAGS_UNLOCKED_ENQUEUE (1 << 2)
86
87	#define DT_CALLOUT_ARMED (1 << 0)
88	#define DT_DRAIN_IN_PROGRESS (1 << 1)
89
90	#ifndef __rtems__
91	#define TQ_LOCK(tq) \
92	do { \
93	if ((tq)->tq_spin) \
94	mtx_lock_spin(&(tq)->tq_mutex); \
95	else \
96	mtx_lock(&(tq)->tq_mutex); \
97	} while (0)
98	#else /* __rtems__ */
99	#define TQ_LOCK(tq) \
100	do { \
101	mtx_lock(&(tq)->tq_mutex); \
102	} while (0)
103	#endif /* __rtems__ */
104	#define TQ_ASSERT_LOCKED(tq) mtx_assert(&(tq)->tq_mutex, MA_OWNED)
105
106	#ifndef __rtems__
107	#define TQ_UNLOCK(tq) \
108	do { \
109	if ((tq)->tq_spin) \
110	mtx_unlock_spin(&(tq)->tq_mutex); \
111	else \
112	mtx_unlock(&(tq)->tq_mutex); \
113	} while (0)
114	#else /* __rtems__ */
115	#define TQ_UNLOCK(tq) \
116	do { \
117	mtx_unlock(&(tq)->tq_mutex); \
118	} while (0)
119	#endif /* __rtems__ */
120	#define TQ_ASSERT_UNLOCKED(tq) mtx_assert(&(tq)->tq_mutex, MA_NOTOWNED)
121
122	void
123	_timeout_task_init(struct taskqueue queue, struct timeout_task timeout_task,
124	int priority, task_fn_t func, void *context)
125	{
126
127	TASK_INIT(&timeout_task->t, priority, func, context);
128	callout_init_mtx(&timeout_task->c, &queue->tq_mutex,
129	CALLOUT_RETURNUNLOCKED);
130	timeout_task->q = queue;
131	timeout_task->f = 0;
132	}
133
134	static __inline int
135	TQ_SLEEP(struct taskqueue tq, void p, struct mtx m, int pri, const char wm,
136	int t)
137	{
138	#ifndef __rtems__
139	if (tq->tq_spin)
140	return (msleep_spin(p, m, wm, t));
141	#endif /* __rtems__ */
142	return (msleep(p, m, pri, wm, t));
143	}
144
145	static struct taskqueue *
146	_taskqueue_create(const char *name, int mflags,
147	taskqueue_enqueue_fn enqueue, void *context,
148	int mtxflags, const char *mtxname __unused)
149	{
150	struct taskqueue *queue;
151	char *tq_name;
152
153	tq_name = malloc(TASKQUEUE_NAMELEN, M_TASKQUEUE, mflags \| M_ZERO);
154	if (tq_name == NULL)
155	return (NULL);
156
157	queue = malloc(sizeof(struct taskqueue), M_TASKQUEUE, mflags \| M_ZERO);
158	if (queue == NULL) {
159	free(tq_name, M_TASKQUEUE);
160	return (NULL);
161	}
162
163	snprintf(tq_name, TASKQUEUE_NAMELEN, "%s", (name) ? name : "taskqueue");
164
165	STAILQ_INIT(&queue->tq_queue);
166	TAILQ_INIT(&queue->tq_active);
167	queue->tq_enqueue = enqueue;
168	queue->tq_context = context;
169	queue->tq_name = tq_name;
170	#ifndef __rtems__
171	queue->tq_spin = (mtxflags & MTX_SPIN) != 0;
172	#else /* __rtems__ */
173	/*
174	* FIXME: Here is a potential performance optimization. Maybe also an
175	* issue for correctness.
176	*/
177	#endif /* __rtems__ */
178	queue->tq_flags \|= TQ_FLAGS_ACTIVE;
179	if (enqueue == taskqueue_fast_enqueue \|\|
180	enqueue == taskqueue_swi_enqueue \|\|
181	enqueue == taskqueue_swi_giant_enqueue \|\|
182	enqueue == taskqueue_thread_enqueue)
183	queue->tq_flags \|= TQ_FLAGS_UNLOCKED_ENQUEUE;
184	mtx_init(&queue->tq_mutex, tq_name, NULL, mtxflags);
185
186	return (queue);
187	}
188
189	struct taskqueue *
190	taskqueue_create(const char *name, int mflags,
191	taskqueue_enqueue_fn enqueue, void *context)
192	{
193
194	return _taskqueue_create(name, mflags, enqueue, context,
195	MTX_DEF, name);
196	}
197
198	void
199	taskqueue_set_callback(struct taskqueue *queue,
200	enum taskqueue_callback_type cb_type, taskqueue_callback_fn callback,
201	void *context)
202	{
203
204	KASSERT(((cb_type >= TASKQUEUE_CALLBACK_TYPE_MIN) &&
205	(cb_type <= TASKQUEUE_CALLBACK_TYPE_MAX)),
206	("Callback type %d not valid, must be %d-%d", cb_type,
207	TASKQUEUE_CALLBACK_TYPE_MIN, TASKQUEUE_CALLBACK_TYPE_MAX));
208	KASSERT((queue->tq_callbacks[cb_type] == NULL),
209	("Re-initialization of taskqueue callback?"));
210
211	queue->tq_callbacks[cb_type] = callback;
212	queue->tq_cb_contexts[cb_type] = context;
213	}
214
215	/*
216	* Signal a taskqueue thread to terminate.
217	*/
218	static void
219	taskqueue_terminate(struct thread *pp, struct taskqueue tq)
220	{
221
222	while (tq->tq_tcount > 0 \|\| tq->tq_callouts > 0) {
223	wakeup(tq);
224	TQ_SLEEP(tq, pp, &tq->tq_mutex, PWAIT, "taskqueue_destroy", 0);
225	}
226	}
227
228	void
229	taskqueue_free(struct taskqueue *queue)
230	{
231
232	TQ_LOCK(queue);
233	queue->tq_flags &= ~TQ_FLAGS_ACTIVE;
234	taskqueue_terminate(queue->tq_threads, queue);
235	KASSERT(TAILQ_EMPTY(&queue->tq_active), ("Tasks still running?"));
236	KASSERT(queue->tq_callouts == 0, ("Armed timeout tasks"));
237	mtx_destroy(&queue->tq_mutex);
238	free(queue->tq_threads, M_TASKQUEUE);
239	free(queue->tq_name, M_TASKQUEUE);
240	free(queue, M_TASKQUEUE);
241	}
242
243	static int
244	taskqueue_enqueue_locked(struct taskqueue queue, struct task task)
245	{
246	struct task *ins;
247	struct task *prev;
248
249	KASSERT(task->ta_func != NULL, ("enqueueing task with NULL func"));
250	/*
251	* Count multiple enqueues.
252	*/
253	if (task->ta_pending) {
254	if (task->ta_pending < USHRT_MAX)
255	task->ta_pending++;
256	TQ_UNLOCK(queue);
257	return (0);
258	}
259
260	/*
261	* Optimise the case when all tasks have the same priority.
262	*/
263	prev = STAILQ_LAST(&queue->tq_queue, task, ta_link);
264	if (!prev \|\| prev->ta_priority >= task->ta_priority) {
265	STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link);
266	} else {
267	prev = NULL;
268	for (ins = STAILQ_FIRST(&queue->tq_queue); ins;
269	prev = ins, ins = STAILQ_NEXT(ins, ta_link))
270	if (ins->ta_priority < task->ta_priority)
271	break;
272
273	if (prev)
274	STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link);
275	else
276	STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link);
277	}
278
279	task->ta_pending = 1;
280	if ((queue->tq_flags & TQ_FLAGS_UNLOCKED_ENQUEUE) != 0)
281	TQ_UNLOCK(queue);
282	if ((queue->tq_flags & TQ_FLAGS_BLOCKED) == 0)
283	queue->tq_enqueue(queue->tq_context);
284	if ((queue->tq_flags & TQ_FLAGS_UNLOCKED_ENQUEUE) == 0)
285	TQ_UNLOCK(queue);
286
287	/* Return with lock released. */
288	return (0);
289	}
290
291	int
292	taskqueue_enqueue(struct taskqueue queue, struct task task)
293	{
294	int res;
295
296	TQ_LOCK(queue);
297	res = taskqueue_enqueue_locked(queue, task);
298	/* The lock is released inside. */
299
300	return (res);
301	}
302
303	static void
304	taskqueue_timeout_func(void *arg)
305	{
306	struct taskqueue *queue;
307	struct timeout_task *timeout_task;
308
309	timeout_task = arg;
310	queue = timeout_task->q;
311	KASSERT((timeout_task->f & DT_CALLOUT_ARMED) != 0, ("Stray timeout"));
312	timeout_task->f &= ~DT_CALLOUT_ARMED;
313	queue->tq_callouts--;
314	taskqueue_enqueue_locked(timeout_task->q, &timeout_task->t);
315	/* The lock is released inside. */
316	}
317
318	int
319	taskqueue_enqueue_timeout(struct taskqueue *queue,
320	struct timeout_task *timeout_task, int ticks)
321	{
322	int res;
323
324	TQ_LOCK(queue);
325	KASSERT(timeout_task->q == NULL \|\| timeout_task->q == queue,
326	("Migrated queue"));
327	#ifndef __rtems__
328	KASSERT(!queue->tq_spin, ("Timeout for spin-queue"));
329	#endif /* __rtems__ */
330	timeout_task->q = queue;
331	res = timeout_task->t.ta_pending;
332	if (timeout_task->f & DT_DRAIN_IN_PROGRESS) {
333	/* Do nothing */
334	TQ_UNLOCK(queue);
335	res = -1;
336	} else if (ticks == 0) {
337	taskqueue_enqueue_locked(queue, &timeout_task->t);
338	/* The lock is released inside. */
339	} else {
340	if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
341	res++;
342	} else {
343	queue->tq_callouts++;
344	timeout_task->f \|= DT_CALLOUT_ARMED;
345	if (ticks < 0)
346	ticks = -ticks; /* Ignore overflow. */
347	}
348	if (ticks > 0) {
349	callout_reset(&timeout_task->c, ticks,
350	taskqueue_timeout_func, timeout_task);
351	}
352	TQ_UNLOCK(queue);
353	}
354	return (res);
355	}
356
357	static void
358	taskqueue_task_nop_fn(void *context, int pending)
359	{
360	}
361
362	/*
363	* Block until all currently queued tasks in this taskqueue
364	* have begun execution. Tasks queued during execution of
365	* this function are ignored.
366	*/
367	static void
368	taskqueue_drain_tq_queue(struct taskqueue *queue)
369	{
370	struct task t_barrier;
371
372	if (STAILQ_EMPTY(&queue->tq_queue))
373	return;
374
375	/*
376	* Enqueue our barrier after all current tasks, but with
377	* the highest priority so that newly queued tasks cannot
378	* pass it. Because of the high priority, we can not use
379	* taskqueue_enqueue_locked directly (which drops the lock
380	* anyway) so just insert it at tail while we have the
381	* queue lock.
382	*/
383	TASK_INIT(&t_barrier, USHRT_MAX, taskqueue_task_nop_fn, &t_barrier);
384	STAILQ_INSERT_TAIL(&queue->tq_queue, &t_barrier, ta_link);
385	t_barrier.ta_pending = 1;
386
387	/*
388	* Once the barrier has executed, all previously queued tasks
389	* have completed or are currently executing.
390	*/
391	while (t_barrier.ta_pending != 0)
392	TQ_SLEEP(queue, &t_barrier, &queue->tq_mutex, PWAIT, "-", 0);
393	}
394
395	/*
396	* Block until all currently executing tasks for this taskqueue
397	* complete. Tasks that begin execution during the execution
398	* of this function are ignored.
399	*/
400	static void
401	taskqueue_drain_tq_active(struct taskqueue *queue)
402	{
403	struct taskqueue_busy tb_marker, *tb_first;
404
405	if (TAILQ_EMPTY(&queue->tq_active))
406	return;
407
408	/* Block taskq_terminate().*/
409	queue->tq_callouts++;
410
411	/*
412	* Wait for all currently executing taskqueue threads
413	* to go idle.
414	*/
415	tb_marker.tb_running = TB_DRAIN_WAITER;
416	TAILQ_INSERT_TAIL(&queue->tq_active, &tb_marker, tb_link);
417	while (TAILQ_FIRST(&queue->tq_active) != &tb_marker)
418	TQ_SLEEP(queue, &tb_marker, &queue->tq_mutex, PWAIT, "-", 0);
419	TAILQ_REMOVE(&queue->tq_active, &tb_marker, tb_link);
420
421	/*
422	* Wakeup any other drain waiter that happened to queue up
423	* without any intervening active thread.
424	*/
425	tb_first = TAILQ_FIRST(&queue->tq_active);
426	if (tb_first != NULL && tb_first->tb_running == TB_DRAIN_WAITER)
427	wakeup(tb_first);
428
429	/* Release taskqueue_terminate(). */
430	queue->tq_callouts--;
431	if ((queue->tq_flags & TQ_FLAGS_ACTIVE) == 0)
432	wakeup_one(queue->tq_threads);
433	}
434
435	void
436	taskqueue_block(struct taskqueue *queue)
437	{
438
439	TQ_LOCK(queue);
440	queue->tq_flags \|= TQ_FLAGS_BLOCKED;
441	TQ_UNLOCK(queue);
442	}
443
444	void
445	taskqueue_unblock(struct taskqueue *queue)
446	{
447
448	TQ_LOCK(queue);
449	queue->tq_flags &= ~TQ_FLAGS_BLOCKED;
450	if (!STAILQ_EMPTY(&queue->tq_queue))
451	queue->tq_enqueue(queue->tq_context);
452	TQ_UNLOCK(queue);
453	}
454
455	static void
456	taskqueue_run_locked(struct taskqueue *queue)
457	{
458	struct taskqueue_busy tb;
459	struct taskqueue_busy *tb_first;
460	struct task *task;
461	int pending;
462
463	KASSERT(queue != NULL, ("tq is NULL"));
464	TQ_ASSERT_LOCKED(queue);
465	tb.tb_running = NULL;
466
467	while (STAILQ_FIRST(&queue->tq_queue)) {
468	TAILQ_INSERT_TAIL(&queue->tq_active, &tb, tb_link);
469
470	/*
471	* Carefully remove the first task from the queue and
472	* zero its pending count.
473	*/
474	task = STAILQ_FIRST(&queue->tq_queue);
475	KASSERT(task != NULL, ("task is NULL"));
476	STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link);
477	pending = task->ta_pending;
478	task->ta_pending = 0;
479	tb.tb_running = task;
480	TQ_UNLOCK(queue);
481
482	KASSERT(task->ta_func != NULL, ("task->ta_func is NULL"));
483	task->ta_func(task->ta_context, pending);
484
485	TQ_LOCK(queue);
486	tb.tb_running = NULL;
487	wakeup(task);
488
489	TAILQ_REMOVE(&queue->tq_active, &tb, tb_link);
490	tb_first = TAILQ_FIRST(&queue->tq_active);
491	if (tb_first != NULL &&
492	tb_first->tb_running == TB_DRAIN_WAITER)
493	wakeup(tb_first);
494	}
495	}
496
497	void
498	taskqueue_run(struct taskqueue *queue)
499	{
500
501	TQ_LOCK(queue);
502	taskqueue_run_locked(queue);
503	TQ_UNLOCK(queue);
504	}
505
506	static int
507	task_is_running(struct taskqueue queue, struct task task)
508	{
509	struct taskqueue_busy *tb;
510
511	TQ_ASSERT_LOCKED(queue);
512	TAILQ_FOREACH(tb, &queue->tq_active, tb_link) {
513	if (tb->tb_running == task)
514	return (1);
515	}
516	return (0);
517	}
518
519	/*
520	* Only use this function in single threaded contexts. It returns
521	* non-zero if the given task is either pending or running. Else the
522	* task is idle and can be queued again or freed.
523	*/
524	int
525	taskqueue_poll_is_busy(struct taskqueue queue, struct task task)
526	{
527	int retval;
528
529	TQ_LOCK(queue);
530	retval = task->ta_pending > 0 \|\| task_is_running(queue, task);
531	TQ_UNLOCK(queue);
532
533	return (retval);
534	}
535
536	static int
537	taskqueue_cancel_locked(struct taskqueue queue, struct task task,
538	u_int *pendp)
539	{
540
541	if (task->ta_pending > 0)
542	STAILQ_REMOVE(&queue->tq_queue, task, task, ta_link);
543	if (pendp != NULL)
544	*pendp = task->ta_pending;
545	task->ta_pending = 0;
546	return (task_is_running(queue, task) ? EBUSY : 0);
547	}
548
549	int
550	taskqueue_cancel(struct taskqueue queue, struct task task, u_int *pendp)
551	{
552	int error;
553
554	TQ_LOCK(queue);
555	error = taskqueue_cancel_locked(queue, task, pendp);
556	TQ_UNLOCK(queue);
557
558	return (error);
559	}
560
561	int
562	taskqueue_cancel_timeout(struct taskqueue *queue,
563	struct timeout_task timeout_task, u_int pendp)
564	{
565	u_int pending, pending1;
566	int error;
567
568	TQ_LOCK(queue);
569	pending = !!(callout_stop(&timeout_task->c) > 0);
570	error = taskqueue_cancel_locked(queue, &timeout_task->t, &pending1);
571	if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
572	timeout_task->f &= ~DT_CALLOUT_ARMED;
573	queue->tq_callouts--;
574	}
575	TQ_UNLOCK(queue);
576
577	if (pendp != NULL)
578	*pendp = pending + pending1;
579	return (error);
580	}
581
582	void
583	taskqueue_drain(struct taskqueue queue, struct task task)
584	{
585
586	#ifndef __rtems__
587	if (!queue->tq_spin)
588	WITNESS_WARN(WARN_GIANTOK \| WARN_SLEEPOK, NULL, __func__);
589	#endif /* __rtems__ */
590
591	TQ_LOCK(queue);
592	while (task->ta_pending != 0 \|\| task_is_running(queue, task))
593	TQ_SLEEP(queue, task, &queue->tq_mutex, PWAIT, "-", 0);
594	TQ_UNLOCK(queue);
595	}
596
597	void
598	taskqueue_drain_all(struct taskqueue *queue)
599	{
600
601	#ifndef __rtems__
602	if (!queue->tq_spin)
603	WITNESS_WARN(WARN_GIANTOK \| WARN_SLEEPOK, NULL, __func__);
604	#endif /* __rtems__ */
605
606	TQ_LOCK(queue);
607	taskqueue_drain_tq_queue(queue);
608	taskqueue_drain_tq_active(queue);
609	TQ_UNLOCK(queue);
610	}
611
612	void
613	taskqueue_drain_timeout(struct taskqueue *queue,
614	struct timeout_task *timeout_task)
615	{
616
617	/*
618	* Set flag to prevent timer from re-starting during drain:
619	*/
620	TQ_LOCK(queue);
621	KASSERT((timeout_task->f & DT_DRAIN_IN_PROGRESS) == 0,
622	("Drain already in progress"));
623	timeout_task->f \|= DT_DRAIN_IN_PROGRESS;
624	TQ_UNLOCK(queue);
625
626	callout_drain(&timeout_task->c);
627	taskqueue_drain(queue, &timeout_task->t);
628
629	/*
630	* Clear flag to allow timer to re-start:
631	*/
632	TQ_LOCK(queue);
633	timeout_task->f &= ~DT_DRAIN_IN_PROGRESS;
634	TQ_UNLOCK(queue);
635	}
636
637	static void
638	taskqueue_swi_enqueue(void *context)
639	{
640	swi_sched(taskqueue_ih, 0);
641	}
642
643	static void
644	taskqueue_swi_run(void *dummy)
645	{
646	taskqueue_run(taskqueue_swi);
647	}
648
649	static void
650	taskqueue_swi_giant_enqueue(void *context)
651	{
652	swi_sched(taskqueue_giant_ih, 0);
653	}
654
655	static void
656	taskqueue_swi_giant_run(void *dummy)
657	{
658	taskqueue_run(taskqueue_swi_giant);
659	}
660
661	static int
662	_taskqueue_start_threads(struct taskqueue **tqp, int count, int pri,
663	cpuset_t mask, const char name, va_list ap)
664	{
665	char ktname[MAXCOMLEN + 1];
666	struct thread *td;
667	struct taskqueue *tq;
668	int i, error;
669
670	if (count <= 0)
671	return (EINVAL);
672
673	vsnprintf(ktname, sizeof(ktname), name, ap);
674	tq = *tqp;
675
676	tq->tq_threads = malloc(sizeof(struct thread ) count, M_TASKQUEUE,
677	M_NOWAIT \| M_ZERO);
678	if (tq->tq_threads == NULL) {
679	printf("%s: no memory for %s threads\n", __func__, ktname);
680	return (ENOMEM);
681	}
682
683	for (i = 0; i < count; i++) {
684	if (count == 1)
685	error = kthread_add(taskqueue_thread_loop, tqp, NULL,
686	&tq->tq_threads[i], RFSTOPPED, 0, "%s", ktname);
687	else
688	error = kthread_add(taskqueue_thread_loop, tqp, NULL,
689	&tq->tq_threads[i], RFSTOPPED, 0,
690	"%s_%d", ktname, i);
691	if (error) {
692	/* should be ok to continue, taskqueue_free will dtrt */
693	printf("%s: kthread_add(%s): error %d", __func__,
694	ktname, error);
695	tq->tq_threads[i] = NULL; /* paranoid */
696	} else
697	tq->tq_tcount++;
698	}
699	if (tq->tq_tcount == 0) {
700	free(tq->tq_threads, M_TASKQUEUE);
701	tq->tq_threads = NULL;
702	return (ENOMEM);
703	}
704	#ifndef __rtems__
705	for (i = 0; i < count; i++) {
706	if (tq->tq_threads[i] == NULL)
707	continue;
708	td = tq->tq_threads[i];
709	if (mask) {
710	error = cpuset_setthread(td->td_tid, mask);
711	/*
712	* Failing to pin is rarely an actual fatal error;
713	* it'll just affect performance.
714	*/
715	if (error)
716	printf("%s: curthread=%llu: can't pin; "
717	"error=%d\n",
718	__func__,
719	(unsigned long long) td->td_tid,
720	error);
721	}
722	thread_lock(td);
723	sched_prio(td, pri);
724	sched_add(td, SRQ_BORING);
725	thread_unlock(td);
726	}
727	#else /* __rtems__ */
728	(void) td;
729	#endif /* __rtems__ */
730
731	return (0);
732	}
733
734	int
735	taskqueue_start_threads(struct taskqueue **tqp, int count, int pri,
736	const char *name, ...)
737	{
738	va_list ap;
739	int error;
740
741	va_start(ap, name);
742	error = _taskqueue_start_threads(tqp, count, pri, NULL, name, ap);
743	va_end(ap);
744	return (error);
745	}
746
747	int
748	taskqueue_start_threads_cpuset(struct taskqueue **tqp, int count, int pri,
749	cpuset_t mask, const char name, ...)
750	{
751	va_list ap;
752	int error;
753
754	va_start(ap, name);
755	error = _taskqueue_start_threads(tqp, count, pri, mask, name, ap);
756	va_end(ap);
757	return (error);
758	}
759
760	static inline void
761	taskqueue_run_callback(struct taskqueue *tq,
762	enum taskqueue_callback_type cb_type)
763	{
764	taskqueue_callback_fn tq_callback;
765
766	TQ_ASSERT_UNLOCKED(tq);
767	tq_callback = tq->tq_callbacks[cb_type];
768	if (tq_callback != NULL)
769	tq_callback(tq->tq_cb_contexts[cb_type]);
770	}
771
772	void
773	taskqueue_thread_loop(void *arg)
774	{
775	struct taskqueue *tqp, tq;
776
777	tqp = arg;
778	tq = *tqp;
779	taskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_INIT);
780	TQ_LOCK(tq);
781	while ((tq->tq_flags & TQ_FLAGS_ACTIVE) != 0) {
782	/* XXX ? */
783	taskqueue_run_locked(tq);
784	/*
785	* Because taskqueue_run() can drop tq_mutex, we need to
786	* check if the TQ_FLAGS_ACTIVE flag wasn't removed in the
787	* meantime, which means we missed a wakeup.
788	*/
789	if ((tq->tq_flags & TQ_FLAGS_ACTIVE) == 0)
790	break;
791	TQ_SLEEP(tq, tq, &tq->tq_mutex, 0, "-", 0);
792	}
793	taskqueue_run_locked(tq);
794	/*
795	* This thread is on its way out, so just drop the lock temporarily
796	* in order to call the shutdown callback. This allows the callback
797	* to look at the taskqueue, even just before it dies.
798	*/
799	TQ_UNLOCK(tq);
800	taskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_SHUTDOWN);
801	TQ_LOCK(tq);
802
803	/* rendezvous with thread that asked us to terminate */
804	tq->tq_tcount--;
805	wakeup_one(tq->tq_threads);
806	TQ_UNLOCK(tq);
807	kthread_exit();
808	}
809
810	void
811	taskqueue_thread_enqueue(void *context)
812	{
813	struct taskqueue *tqp, tq;
814
815	tqp = context;
816	tq = *tqp;
817	wakeup_one(tq);
818	}
819
820	TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, NULL,
821	swi_add(NULL, "task queue", taskqueue_swi_run, NULL, SWI_TQ,
822	INTR_MPSAFE, &taskqueue_ih));
823
824	TASKQUEUE_DEFINE(swi_giant, taskqueue_swi_giant_enqueue, NULL,
825	swi_add(NULL, "Giant taskq", taskqueue_swi_giant_run,
826	NULL, SWI_TQ_GIANT, 0, &taskqueue_giant_ih));
827
828	TASKQUEUE_DEFINE_THREAD(thread);
829
830	struct taskqueue *
831	taskqueue_create_fast(const char *name, int mflags,
832	taskqueue_enqueue_fn enqueue, void *context)
833	{
834	return _taskqueue_create(name, mflags, enqueue, context,
835	MTX_SPIN, "fast_taskqueue");
836	}
837
838	static void *taskqueue_fast_ih;
839
840	static void
841	taskqueue_fast_enqueue(void *context)
842	{
843	swi_sched(taskqueue_fast_ih, 0);
844	}
845
846	static void
847	taskqueue_fast_run(void *dummy)
848	{
849	taskqueue_run(taskqueue_fast);
850	}
851
852	TASKQUEUE_FAST_DEFINE(fast, taskqueue_fast_enqueue, NULL,
853	swi_add(NULL, "fast taskq", taskqueue_fast_run, NULL,
854	SWI_TQ_FAST, INTR_MPSAFE, &taskqueue_fast_ih));
855
856	int
857	taskqueue_member(struct taskqueue queue, struct thread td)
858	{
859	int i, j, ret = 0;
860
861	for (i = 0, j = 0; ; i++) {
862	if (queue->tq_threads[i] == NULL)
863	continue;
864	if (queue->tq_threads[i] == td) {
865	ret = 1;
866	break;
867	}
868	if (++j >= queue->tq_tcount)
869	break;
870	}
871	return (ret);
872	}

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