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: head/sys/kern/subr_taskqueue.c 180583 2008-07-18 06:12:31Z kmacy $");
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/ktr.h>
36#include <sys/kthread.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 STAILQ_HEAD(taskqueue_list, taskqueue) taskqueue_queues;
50static struct mtx taskqueue_queues_mutex;
51
52STAILQ_HEAD(task_head, task);
53
54struct taskqueue {
55 STAILQ_ENTRY(taskqueue) tq_link;
56 STAILQ_HEAD(, task) tq_queue;
57 const char *tq_name;
58 taskqueue_enqueue_fn tq_enqueue;
59 void *tq_context;
60 struct task *tq_running;
61 struct mtx tq_mutex;
62 struct thread **tq_threads;
63 int tq_tcount;
64 int tq_flags;
65};
66
67#define TQ_FLAGS_ACTIVE (1 << 0)
68#define TQ_FLAGS_BLOCKED (1 << 1)
69#define TQ_FLAGS_PENDING (1 << 2)
70#define TQ_FLAGS_SPIN (1 << 3)
71#define TQ_FLAGS_NOWAKEUP (1 << 4)
72#define TQ_FLAGS_RUNNING (1 << 5)
73
74#define TQ_LOCK(tq) \
75do { \
76 \
77 if (tq->tq_flags & TQ_FLAGS_SPIN) \
78 mtx_lock_spin(&tq->tq_mutex); \
79 else \
80 mtx_lock(&tq->tq_mutex); \
81} while (0)
82
83
84#define TQ_UNLOCK(tq) \
85do { \
86 \
87 if (tq->tq_flags & TQ_FLAGS_SPIN) \
88 mtx_unlock_spin(&tq->tq_mutex); \
89 else \
90 mtx_unlock(&tq->tq_mutex); \
91} while (0)
92
93
94static void init_taskqueue_list(void *data);
95
96static __inline int
97TQ_SLEEP(struct taskqueue *tq, void *p, struct mtx *m, int pri, const char *wm,
98 int t)
99{
100 if (tq->tq_flags & TQ_FLAGS_SPIN)
101 return (msleep_spin(p, m, wm, t));
102 return (msleep(p, m, pri, wm, t));
103}
104
105static void
106init_taskqueue_list(void *data __unused)
107{
108
109 mtx_init(&taskqueue_queues_mutex, "taskqueue list", NULL, MTX_DEF);
110 STAILQ_INIT(&taskqueue_queues);
111}
112SYSINIT(taskqueue_list, SI_SUB_INTRINSIC, SI_ORDER_ANY, init_taskqueue_list,
113 NULL);
114
115static struct taskqueue *
116_taskqueue_create(const char *name, int mflags,
117 taskqueue_enqueue_fn enqueue, void *context,
118 int mtxflags, const char *mtxname)
119{
120 struct taskqueue *queue;
121 int spin;
122
123
124 queue = malloc(sizeof(struct taskqueue), M_TASKQUEUE, mflags | M_ZERO);
125 if (!queue)
126 return 0;
127 spin = ((mtxflags & MTX_SPIN) ? TQ_FLAGS_SPIN : 0);
128 STAILQ_INIT(&queue->tq_queue);
129 queue->tq_name = name;
130 queue->tq_enqueue = enqueue;
131 queue->tq_context = context;
132 queue->tq_flags |= TQ_FLAGS_ACTIVE | spin;
133 mtx_init(&queue->tq_mutex, mtxname, NULL, mtxflags);
134
135 mtx_lock(&taskqueue_queues_mutex);
136 STAILQ_INSERT_TAIL(&taskqueue_queues, queue, tq_link);
137 mtx_unlock(&taskqueue_queues_mutex);
138
139 return queue;
140}
141
142struct taskqueue *
143taskqueue_create(const char *name, int mflags,
144 taskqueue_enqueue_fn enqueue, void *context)
145{
146 return _taskqueue_create(name, mflags, enqueue, context,
147 MTX_DEF, "taskqueue");
148}
149
150/*
151 * Signal a taskqueue thread to terminate.
152 */
153static void
154taskqueue_terminate(struct thread **pp, struct taskqueue *tq)
155{
156
157 while (tq->tq_tcount > 0) {
158 wakeup(tq);
159 TQ_SLEEP(tq, pp, &tq->tq_mutex, PWAIT, "taskqueue_destroy", 0);
160 }
161}
162
163void
164taskqueue_free(struct taskqueue *queue)
165{
166
167 mtx_lock(&taskqueue_queues_mutex);
168 STAILQ_REMOVE(&taskqueue_queues, queue, taskqueue, tq_link);
169 mtx_unlock(&taskqueue_queues_mutex);
170
171 TQ_LOCK(queue);
172 queue->tq_flags &= ~TQ_FLAGS_ACTIVE;
173 taskqueue_run(queue);
174 taskqueue_terminate(queue->tq_threads, queue);
175 mtx_destroy(&queue->tq_mutex);
176 free(queue->tq_threads, M_TASKQUEUE);
177 free(queue, M_TASKQUEUE);
178}
179
180/*
181 * Returns with the taskqueue locked.
182 */
183struct taskqueue *
184taskqueue_find(const char *name)
185{
186 struct taskqueue *queue;
187
188 mtx_lock(&taskqueue_queues_mutex);
189 STAILQ_FOREACH(queue, &taskqueue_queues, tq_link) {
190 if (strcmp(queue->tq_name, name) == 0) {
191 TQ_LOCK(queue);
192 mtx_unlock(&taskqueue_queues_mutex);
193 return queue;
194 }
195 }
196 mtx_unlock(&taskqueue_queues_mutex);
197 return NULL;
198}
199
200int
201taskqueue_enqueue(struct taskqueue *queue, struct task *task)
202{
203 struct task *ins;
204 struct task *prev;
205
206 TQ_LOCK(queue);
207
208 /*
209 * Count multiple enqueues.
210 */
211 if (task->ta_pending || (task->ta_flags & TA_REFERENCED)) {
212 task->ta_pending++;
213 /*
214 * overflow
215 */
216 if (task->ta_pending == 0)
217 task->ta_pending--;
218
219 TQ_UNLOCK(queue);
220 return 0;
221 }
222
223 /*
224 * Optimise the case when all tasks have the same priority.
225 */
226 prev = STAILQ_LAST(&queue->tq_queue, task, ta_link);
227 if (!prev || prev->ta_priority >= task->ta_priority) {
228 STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link);
229 } else {
230 prev = 0;
231 for (ins = STAILQ_FIRST(&queue->tq_queue); ins;
232 prev = ins, ins = STAILQ_NEXT(ins, ta_link))
233 if (ins->ta_priority < task->ta_priority)
234 break;
235
236 if (prev)
237 STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link);
238 else
239 STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link);
240 }
241
242 task->ta_pending = 1;
243 if ((queue->tq_flags & (TQ_FLAGS_BLOCKED|TQ_FLAGS_RUNNING)) == 0)
244 queue->tq_enqueue(queue->tq_context);
245 else if (queue->tq_flags & TQ_FLAGS_BLOCKED)
246 queue->tq_flags |= TQ_FLAGS_PENDING;
247
248 TQ_UNLOCK(queue);
249
250 return 0;
251}
252
253void
254taskqueue_block(struct taskqueue *queue)
255{
256
257 TQ_LOCK(queue);
258 queue->tq_flags |= TQ_FLAGS_BLOCKED;
259 TQ_UNLOCK(queue);
260}
261
262void
263taskqueue_unblock(struct taskqueue *queue)
264{
265
266 TQ_LOCK(queue);
267 queue->tq_flags &= ~TQ_FLAGS_BLOCKED;
268 if (queue->tq_flags & TQ_FLAGS_PENDING) {
269 queue->tq_flags &= ~TQ_FLAGS_PENDING;
270 queue->tq_enqueue(queue->tq_context);
271 }
272 TQ_UNLOCK(queue);
273}
274
275void
276taskqueue_run(struct taskqueue *queue)
277{
278 struct task *task;
279 int owned, pending;
280
281 owned = mtx_owned(&queue->tq_mutex);
282 if (!owned)
283 TQ_LOCK(queue);
284 while (STAILQ_FIRST(&queue->tq_queue)) {
285 /*
286 * Carefully remove the first task from the queue and
287 * zero its pending count.
288 */
289 task = STAILQ_FIRST(&queue->tq_queue);
290 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link);
291 pending = task->ta_pending;
292 task->ta_pending = 0;
293 queue->tq_running = task;
294 TQ_UNLOCK(queue);
295
296 task->ta_func(task->ta_context, pending);
297
298 TQ_LOCK(queue);
299 queue->tq_running = NULL;
300 wakeup(task);
301 }
302
303 /*
304 * For compatibility, unlock on return if the queue was not locked
305 * on entry, although this opens a race window.
306 */
307 if (!owned)
308 TQ_UNLOCK(queue);
309}
310
311void
312taskqueue_drain(struct taskqueue *queue, struct task *task)
313{
314 if (queue->tq_flags & TQ_FLAGS_SPIN) { /* XXX */
315 mtx_lock_spin(&queue->tq_mutex);
316 while (task->ta_pending != 0 || task == queue->tq_running)
317 msleep_spin(task, &queue->tq_mutex, "-", 0);
318 mtx_unlock_spin(&queue->tq_mutex);
319 } else {
320 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
321
322 mtx_lock(&queue->tq_mutex);
323 while (task->ta_pending != 0 || task == queue->tq_running)
324 msleep(task, &queue->tq_mutex, PWAIT, "-", 0);
325 mtx_unlock(&queue->tq_mutex);
326 }
327}
328
329static void
330taskqueue_swi_enqueue(void *context)
331{
332 swi_sched(taskqueue_ih, 0);
333}
334
335static void
336taskqueue_swi_run(void *dummy)
337{
338 taskqueue_run(taskqueue_swi);
339}
340
341static void
342taskqueue_swi_giant_enqueue(void *context)
343{
344 swi_sched(taskqueue_giant_ih, 0);
345}
346
347static void
348taskqueue_swi_giant_run(void *dummy)
349{
350 taskqueue_run(taskqueue_swi_giant);
351}
352
353int
354taskqueue_start_threads(struct taskqueue **tqp, int count, int pri,
355 const char *name, ...)
356{
357 va_list ap;
358 struct thread *td;
359 struct taskqueue *tq;
360 int i, error;
361 char ktname[MAXCOMLEN];
362
363 if (count <= 0)
364 return (EINVAL);
365
366 tq = *tqp;
367
368 va_start(ap, name);
369 vsnprintf(ktname, MAXCOMLEN, name, ap);
370 va_end(ap);
371
372 tq->tq_threads = malloc(sizeof(struct thread *) * count, M_TASKQUEUE,
373 M_NOWAIT | M_ZERO);
374 if (tq->tq_threads == NULL) {
375 printf("%s: no memory for %s threads\n", __func__, ktname);
376 return (ENOMEM);
377 }
378
379 for (i = 0; i < count; i++) {
380 if (count == 1)
381 error = kthread_add(taskqueue_thread_loop, tqp, NULL,
382 &tq->tq_threads[i], RFSTOPPED, 0, ktname);
383 else
384 error = kthread_add(taskqueue_thread_loop, tqp, NULL,
385 &tq->tq_threads[i], RFSTOPPED, 0,
386 "%s_%d", ktname, i);
387 if (error) {
388 /* should be ok to continue, taskqueue_free will dtrt */
389 printf("%s: kthread_add(%s): error %d", __func__,
390 ktname, error);
391 tq->tq_threads[i] = NULL; /* paranoid */
392 } else
393 tq->tq_tcount++;
394 }
395 for (i = 0; i < count; i++) {
396 if (tq->tq_threads[i] == NULL)
397 continue;
398 td = tq->tq_threads[i];
399 thread_lock(td);
400 sched_prio(td, pri);
401 sched_add(td, SRQ_BORING);
402 thread_unlock(td);
403 }
404
405 return (0);
406}
407
408void
409taskqueue_thread_loop(void *arg)
410{
411 struct taskqueue **tqp, *tq;
412
413 tqp = arg;
414 tq = *tqp;
415 TQ_LOCK(tq);
416 do {
417 taskqueue_run(tq);
418 TQ_SLEEP(tq, tq, &tq->tq_mutex, 0, "-", 0);
419 } while ((tq->tq_flags & TQ_FLAGS_ACTIVE) != 0);
420
421 /* rendezvous with thread that asked us to terminate */
422 tq->tq_tcount--;
423 wakeup_one(tq->tq_threads);
424 TQ_UNLOCK(tq);
425 kthread_exit();
426}
427
428void
429taskqueue_thread_enqueue(void *context)
430{
431 struct taskqueue **tqp, *tq;
432
433 tqp = context;
434 tq = *tqp;
435
436 mtx_assert(&tq->tq_mutex, MA_OWNED);
437 wakeup_one(tq);
438}
439
440TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, 0,
441 swi_add(NULL, "task queue", taskqueue_swi_run, NULL, SWI_TQ,
442 INTR_MPSAFE, &taskqueue_ih));
443
444TASKQUEUE_DEFINE(swi_giant, taskqueue_swi_giant_enqueue, 0,
445 swi_add(NULL, "Giant taskq", taskqueue_swi_giant_run,
446 NULL, SWI_TQ_GIANT, 0, &taskqueue_giant_ih));
447
448TASKQUEUE_DEFINE_THREAD(thread);
449
450struct taskqueue *
451taskqueue_create_fast(const char *name, int mflags,
452 taskqueue_enqueue_fn enqueue, void *context)
453{
454 return _taskqueue_create(name, mflags, enqueue, context,
455 MTX_SPIN, "fast_taskqueue");
456}
457
458/* NB: for backwards compatibility */
459int
460taskqueue_enqueue_fast(struct taskqueue *queue, struct task *task)
461{
462 return taskqueue_enqueue(queue, task);
463}
464
465static void *taskqueue_fast_ih;
466
467static void
468taskqueue_fast_enqueue(void *context)
469{
470 swi_sched(taskqueue_fast_ih, 0);
471}
472
473static void
474taskqueue_fast_run(void *dummy)
475{
476 taskqueue_run(taskqueue_fast);
477}
478
479TASKQUEUE_FAST_DEFINE(fast, taskqueue_fast_enqueue, 0,
480 swi_add(NULL, "Fast task queue", taskqueue_fast_run, NULL,
481 SWI_TQ_FAST, INTR_MPSAFE, &taskqueue_fast_ih));
482
483static void
484taskqueue_run_drv(void *arg)
485{
486 struct task *task, *tmp;
487 struct task_head current;
488 int restarts = 0;
489 struct taskqueue *queue = (struct taskqueue *) arg;
490
491 STAILQ_INIT(¤t);
492 /*
493 * First we move all of the tasks off of the taskqueue's list
494 * on to current on the stack to avoided repeated serialization
495 */
496 mtx_lock_spin(&queue->tq_mutex);
497 queue->tq_flags |= TQ_FLAGS_RUNNING;
498restart:
499 STAILQ_CONCAT(¤t, &queue->tq_queue);
500 STAILQ_FOREACH(task, ¤t, ta_link) {
501 /*
502 * to let taskqueue_enqueue_fast know that this task
503 * has been dequeued but is referenced
504 * clear pending so that if pending is later set we know that it
505 * it needs to be re-enqueued even if the task doesn't return
506 * TA_NO_DEQUEUE
507 */
508 task->ta_ppending = task->ta_pending;
509 task->ta_pending = 0;
510 task->ta_flags |= TA_REFERENCED;
511 }
512 mtx_unlock_spin(&queue->tq_mutex);
513 STAILQ_FOREACH(task, ¤t, ta_link) {
514 task->ta_rc = task->ta_drv_func(task->ta_context, task->ta_ppending);
515
516 }
517 /*
518 * We've gotten here so we know that we've run the tasks that were
519 * on the taskqueue list on the first pass
520 */
521 mtx_lock_spin(&queue->tq_mutex);
522 STAILQ_FOREACH_SAFE(task, ¤t, ta_link, tmp) {
523 if (task->ta_rc != TA_NO_DEQUEUE && task->ta_pending == 0) {
524 STAILQ_REMOVE(¤t, task, task, ta_link);
525 task->ta_flags &= ~TA_REFERENCED;
526 }
527 task->ta_ppending = 0;
528 task->ta_rc = 0;
529 }
530 /*
531 * restart if there are any tasks in the list
532 */
533 if (STAILQ_FIRST(¤t) || STAILQ_FIRST(&queue->tq_queue)) {
534 restarts++;
535 goto restart;
536 }
537 queue->tq_flags &= ~TQ_FLAGS_RUNNING;
538 mtx_unlock_spin(&queue->tq_mutex);
539 CTR2(KTR_INTR, "queue=%s returning from taskqueue_run_drv after %d restarts", queue->tq_name, restarts);
540}
541
542static void
543taskqueue_drv_schedule(void *context)
544{
545 swi_sched(context, 0);
546}
547
548struct taskqueue *
549taskqueue_define_drv(void *arg, const char *name)
550{
551 struct taskqueue *tq;
552 struct thread *td;
553
554 tq = malloc(sizeof(struct taskqueue), M_TASKQUEUE,
555 M_NOWAIT | M_ZERO);
556 if (!tq) {
557 printf("%s: Unable to allocate fast drv task queue!\n",
558 __func__);
559 return (NULL);
560 }
561
562 STAILQ_INIT(&tq->tq_queue);
563 tq->tq_name = name;
564 tq->tq_enqueue = taskqueue_drv_schedule;
565 tq->tq_flags = (TQ_FLAGS_ACTIVE | TQ_FLAGS_SPIN | TQ_FLAGS_NOWAKEUP);
566 mtx_init(&tq->tq_mutex, name, NULL, MTX_SPIN);
567
568 mtx_lock(&taskqueue_queues_mutex);
569 STAILQ_INSERT_TAIL(&taskqueue_queues, tq, tq_link);
570 mtx_unlock(&taskqueue_queues_mutex);
571
572 swi_add(NULL, name, taskqueue_run_drv,
573 tq, SWI_NET, INTR_MPSAFE, &tq->tq_context);
574 td = intr_handler_thread((struct intr_handler *) tq->tq_context);
575 return (tq);
576}
577
578struct intr_handler *
579taskqueue_drv_handler(struct taskqueue *tq)
580{
581 return ((struct intr_handler *) tq->tq_context);
582}
583
584struct thread *
585taskqueue_drv_thread(void *context)
586{
587 struct taskqueue *tq = (struct taskqueue *) context;
588
589 return (intr_handler_thread((struct intr_handler *) tq->tq_context));
590}
591
592/*
593 * Caller must make sure that there must not be any new tasks getting queued
594 * before calling this.
595 */
596void
597taskqueue_free_drv(struct taskqueue *queue)
598{
599 struct intr_thread *ithd;
600 struct intr_event *ie;
601
602 mtx_lock(&taskqueue_queues_mutex);
603 STAILQ_REMOVE(&taskqueue_queues, queue, taskqueue, tq_link);
604 mtx_unlock(&taskqueue_queues_mutex);
605
606 ie = ((struct intr_handler *)(queue->tq_context))->ih_event;
607 ithd = ie->ie_thread;
608 swi_remove(queue->tq_context);
609 intr_event_destroy(ie);
610
611 mtx_lock_spin(&queue->tq_mutex);
612 taskqueue_run(queue);
613 mtx_destroy(&queue->tq_mutex);
614 free(queue, M_TASKQUEUE);
615}
616
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: head/sys/kern/subr_taskqueue.c 180583 2008-07-18 06:12:31Z kmacy $");
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/ktr.h>
36#include <sys/kthread.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 STAILQ_HEAD(taskqueue_list, taskqueue) taskqueue_queues;
50static struct mtx taskqueue_queues_mutex;
51
52STAILQ_HEAD(task_head, task);
53
54struct taskqueue {
55 STAILQ_ENTRY(taskqueue) tq_link;
56 STAILQ_HEAD(, task) tq_queue;
57 const char *tq_name;
58 taskqueue_enqueue_fn tq_enqueue;
59 void *tq_context;
60 struct task *tq_running;
61 struct mtx tq_mutex;
62 struct thread **tq_threads;
63 int tq_tcount;
64 int tq_flags;
65};
66
67#define TQ_FLAGS_ACTIVE (1 << 0)
68#define TQ_FLAGS_BLOCKED (1 << 1)
69#define TQ_FLAGS_PENDING (1 << 2)
70#define TQ_FLAGS_SPIN (1 << 3)
71#define TQ_FLAGS_NOWAKEUP (1 << 4)
72#define TQ_FLAGS_RUNNING (1 << 5)
73
74#define TQ_LOCK(tq) \
75do { \
76 \
77 if (tq->tq_flags & TQ_FLAGS_SPIN) \
78 mtx_lock_spin(&tq->tq_mutex); \
79 else \
80 mtx_lock(&tq->tq_mutex); \
81} while (0)
82
83
84#define TQ_UNLOCK(tq) \
85do { \
86 \
87 if (tq->tq_flags & TQ_FLAGS_SPIN) \
88 mtx_unlock_spin(&tq->tq_mutex); \
89 else \
90 mtx_unlock(&tq->tq_mutex); \
91} while (0)
92
93
94static void init_taskqueue_list(void *data);
95
96static __inline int
97TQ_SLEEP(struct taskqueue *tq, void *p, struct mtx *m, int pri, const char *wm,
98 int t)
99{
100 if (tq->tq_flags & TQ_FLAGS_SPIN)
101 return (msleep_spin(p, m, wm, t));
102 return (msleep(p, m, pri, wm, t));
103}
104
105static void
106init_taskqueue_list(void *data __unused)
107{
108
109 mtx_init(&taskqueue_queues_mutex, "taskqueue list", NULL, MTX_DEF);
110 STAILQ_INIT(&taskqueue_queues);
111}
112SYSINIT(taskqueue_list, SI_SUB_INTRINSIC, SI_ORDER_ANY, init_taskqueue_list,
113 NULL);
114
115static struct taskqueue *
116_taskqueue_create(const char *name, int mflags,
117 taskqueue_enqueue_fn enqueue, void *context,
118 int mtxflags, const char *mtxname)
119{
120 struct taskqueue *queue;
121 int spin;
122
123
124 queue = malloc(sizeof(struct taskqueue), M_TASKQUEUE, mflags | M_ZERO);
125 if (!queue)
126 return 0;
127 spin = ((mtxflags & MTX_SPIN) ? TQ_FLAGS_SPIN : 0);
128 STAILQ_INIT(&queue->tq_queue);
129 queue->tq_name = name;
130 queue->tq_enqueue = enqueue;
131 queue->tq_context = context;
132 queue->tq_flags |= TQ_FLAGS_ACTIVE | spin;
133 mtx_init(&queue->tq_mutex, mtxname, NULL, mtxflags);
134
135 mtx_lock(&taskqueue_queues_mutex);
136 STAILQ_INSERT_TAIL(&taskqueue_queues, queue, tq_link);
137 mtx_unlock(&taskqueue_queues_mutex);
138
139 return queue;
140}
141
142struct taskqueue *
143taskqueue_create(const char *name, int mflags,
144 taskqueue_enqueue_fn enqueue, void *context)
145{
146 return _taskqueue_create(name, mflags, enqueue, context,
147 MTX_DEF, "taskqueue");
148}
149
150/*
151 * Signal a taskqueue thread to terminate.
152 */
153static void
154taskqueue_terminate(struct thread **pp, struct taskqueue *tq)
155{
156
157 while (tq->tq_tcount > 0) {
158 wakeup(tq);
159 TQ_SLEEP(tq, pp, &tq->tq_mutex, PWAIT, "taskqueue_destroy", 0);
160 }
161}
162
163void
164taskqueue_free(struct taskqueue *queue)
165{
166
167 mtx_lock(&taskqueue_queues_mutex);
168 STAILQ_REMOVE(&taskqueue_queues, queue, taskqueue, tq_link);
169 mtx_unlock(&taskqueue_queues_mutex);
170
171 TQ_LOCK(queue);
172 queue->tq_flags &= ~TQ_FLAGS_ACTIVE;
173 taskqueue_run(queue);
174 taskqueue_terminate(queue->tq_threads, queue);
175 mtx_destroy(&queue->tq_mutex);
176 free(queue->tq_threads, M_TASKQUEUE);
177 free(queue, M_TASKQUEUE);
178}
179
180/*
181 * Returns with the taskqueue locked.
182 */
183struct taskqueue *
184taskqueue_find(const char *name)
185{
186 struct taskqueue *queue;
187
188 mtx_lock(&taskqueue_queues_mutex);
189 STAILQ_FOREACH(queue, &taskqueue_queues, tq_link) {
190 if (strcmp(queue->tq_name, name) == 0) {
191 TQ_LOCK(queue);
192 mtx_unlock(&taskqueue_queues_mutex);
193 return queue;
194 }
195 }
196 mtx_unlock(&taskqueue_queues_mutex);
197 return NULL;
198}
199
200int
201taskqueue_enqueue(struct taskqueue *queue, struct task *task)
202{
203 struct task *ins;
204 struct task *prev;
205
206 TQ_LOCK(queue);
207
208 /*
209 * Count multiple enqueues.
210 */
211 if (task->ta_pending || (task->ta_flags & TA_REFERENCED)) {
212 task->ta_pending++;
213 /*
214 * overflow
215 */
216 if (task->ta_pending == 0)
217 task->ta_pending--;
218
219 TQ_UNLOCK(queue);
220 return 0;
221 }
222
223 /*
224 * Optimise the case when all tasks have the same priority.
225 */
226 prev = STAILQ_LAST(&queue->tq_queue, task, ta_link);
227 if (!prev || prev->ta_priority >= task->ta_priority) {
228 STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link);
229 } else {
230 prev = 0;
231 for (ins = STAILQ_FIRST(&queue->tq_queue); ins;
232 prev = ins, ins = STAILQ_NEXT(ins, ta_link))
233 if (ins->ta_priority < task->ta_priority)
234 break;
235
236 if (prev)
237 STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link);
238 else
239 STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link);
240 }
241
242 task->ta_pending = 1;
243 if ((queue->tq_flags & (TQ_FLAGS_BLOCKED|TQ_FLAGS_RUNNING)) == 0)
244 queue->tq_enqueue(queue->tq_context);
245 else if (queue->tq_flags & TQ_FLAGS_BLOCKED)
246 queue->tq_flags |= TQ_FLAGS_PENDING;
247
248 TQ_UNLOCK(queue);
249
250 return 0;
251}
252
253void
254taskqueue_block(struct taskqueue *queue)
255{
256
257 TQ_LOCK(queue);
258 queue->tq_flags |= TQ_FLAGS_BLOCKED;
259 TQ_UNLOCK(queue);
260}
261
262void
263taskqueue_unblock(struct taskqueue *queue)
264{
265
266 TQ_LOCK(queue);
267 queue->tq_flags &= ~TQ_FLAGS_BLOCKED;
268 if (queue->tq_flags & TQ_FLAGS_PENDING) {
269 queue->tq_flags &= ~TQ_FLAGS_PENDING;
270 queue->tq_enqueue(queue->tq_context);
271 }
272 TQ_UNLOCK(queue);
273}
274
275void
276taskqueue_run(struct taskqueue *queue)
277{
278 struct task *task;
279 int owned, pending;
280
281 owned = mtx_owned(&queue->tq_mutex);
282 if (!owned)
283 TQ_LOCK(queue);
284 while (STAILQ_FIRST(&queue->tq_queue)) {
285 /*
286 * Carefully remove the first task from the queue and
287 * zero its pending count.
288 */
289 task = STAILQ_FIRST(&queue->tq_queue);
290 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link);
291 pending = task->ta_pending;
292 task->ta_pending = 0;
293 queue->tq_running = task;
294 TQ_UNLOCK(queue);
295
296 task->ta_func(task->ta_context, pending);
297
298 TQ_LOCK(queue);
299 queue->tq_running = NULL;
300 wakeup(task);
301 }
302
303 /*
304 * For compatibility, unlock on return if the queue was not locked
305 * on entry, although this opens a race window.
306 */
307 if (!owned)
308 TQ_UNLOCK(queue);
309}
310
311void
312taskqueue_drain(struct taskqueue *queue, struct task *task)
313{
314 if (queue->tq_flags & TQ_FLAGS_SPIN) { /* XXX */
315 mtx_lock_spin(&queue->tq_mutex);
316 while (task->ta_pending != 0 || task == queue->tq_running)
317 msleep_spin(task, &queue->tq_mutex, "-", 0);
318 mtx_unlock_spin(&queue->tq_mutex);
319 } else {
320 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
321
322 mtx_lock(&queue->tq_mutex);
323 while (task->ta_pending != 0 || task == queue->tq_running)
324 msleep(task, &queue->tq_mutex, PWAIT, "-", 0);
325 mtx_unlock(&queue->tq_mutex);
326 }
327}
328
329static void
330taskqueue_swi_enqueue(void *context)
331{
332 swi_sched(taskqueue_ih, 0);
333}
334
335static void
336taskqueue_swi_run(void *dummy)
337{
338 taskqueue_run(taskqueue_swi);
339}
340
341static void
342taskqueue_swi_giant_enqueue(void *context)
343{
344 swi_sched(taskqueue_giant_ih, 0);
345}
346
347static void
348taskqueue_swi_giant_run(void *dummy)
349{
350 taskqueue_run(taskqueue_swi_giant);
351}
352
353int
354taskqueue_start_threads(struct taskqueue **tqp, int count, int pri,
355 const char *name, ...)
356{
357 va_list ap;
358 struct thread *td;
359 struct taskqueue *tq;
360 int i, error;
361 char ktname[MAXCOMLEN];
362
363 if (count <= 0)
364 return (EINVAL);
365
366 tq = *tqp;
367
368 va_start(ap, name);
369 vsnprintf(ktname, MAXCOMLEN, name, ap);
370 va_end(ap);
371
372 tq->tq_threads = malloc(sizeof(struct thread *) * count, M_TASKQUEUE,
373 M_NOWAIT | M_ZERO);
374 if (tq->tq_threads == NULL) {
375 printf("%s: no memory for %s threads\n", __func__, ktname);
376 return (ENOMEM);
377 }
378
379 for (i = 0; i < count; i++) {
380 if (count == 1)
381 error = kthread_add(taskqueue_thread_loop, tqp, NULL,
382 &tq->tq_threads[i], RFSTOPPED, 0, ktname);
383 else
384 error = kthread_add(taskqueue_thread_loop, tqp, NULL,
385 &tq->tq_threads[i], RFSTOPPED, 0,
386 "%s_%d", ktname, i);
387 if (error) {
388 /* should be ok to continue, taskqueue_free will dtrt */
389 printf("%s: kthread_add(%s): error %d", __func__,
390 ktname, error);
391 tq->tq_threads[i] = NULL; /* paranoid */
392 } else
393 tq->tq_tcount++;
394 }
395 for (i = 0; i < count; i++) {
396 if (tq->tq_threads[i] == NULL)
397 continue;
398 td = tq->tq_threads[i];
399 thread_lock(td);
400 sched_prio(td, pri);
401 sched_add(td, SRQ_BORING);
402 thread_unlock(td);
403 }
404
405 return (0);
406}
407
408void
409taskqueue_thread_loop(void *arg)
410{
411 struct taskqueue **tqp, *tq;
412
413 tqp = arg;
414 tq = *tqp;
415 TQ_LOCK(tq);
416 do {
417 taskqueue_run(tq);
418 TQ_SLEEP(tq, tq, &tq->tq_mutex, 0, "-", 0);
419 } while ((tq->tq_flags & TQ_FLAGS_ACTIVE) != 0);
420
421 /* rendezvous with thread that asked us to terminate */
422 tq->tq_tcount--;
423 wakeup_one(tq->tq_threads);
424 TQ_UNLOCK(tq);
425 kthread_exit();
426}
427
428void
429taskqueue_thread_enqueue(void *context)
430{
431 struct taskqueue **tqp, *tq;
432
433 tqp = context;
434 tq = *tqp;
435
436 mtx_assert(&tq->tq_mutex, MA_OWNED);
437 wakeup_one(tq);
438}
439
440TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, 0,
441 swi_add(NULL, "task queue", taskqueue_swi_run, NULL, SWI_TQ,
442 INTR_MPSAFE, &taskqueue_ih));
443
444TASKQUEUE_DEFINE(swi_giant, taskqueue_swi_giant_enqueue, 0,
445 swi_add(NULL, "Giant taskq", taskqueue_swi_giant_run,
446 NULL, SWI_TQ_GIANT, 0, &taskqueue_giant_ih));
447
448TASKQUEUE_DEFINE_THREAD(thread);
449
450struct taskqueue *
451taskqueue_create_fast(const char *name, int mflags,
452 taskqueue_enqueue_fn enqueue, void *context)
453{
454 return _taskqueue_create(name, mflags, enqueue, context,
455 MTX_SPIN, "fast_taskqueue");
456}
457
458/* NB: for backwards compatibility */
459int
460taskqueue_enqueue_fast(struct taskqueue *queue, struct task *task)
461{
462 return taskqueue_enqueue(queue, task);
463}
464
465static void *taskqueue_fast_ih;
466
467static void
468taskqueue_fast_enqueue(void *context)
469{
470 swi_sched(taskqueue_fast_ih, 0);
471}
472
473static void
474taskqueue_fast_run(void *dummy)
475{
476 taskqueue_run(taskqueue_fast);
477}
478
479TASKQUEUE_FAST_DEFINE(fast, taskqueue_fast_enqueue, 0,
480 swi_add(NULL, "Fast task queue", taskqueue_fast_run, NULL,
481 SWI_TQ_FAST, INTR_MPSAFE, &taskqueue_fast_ih));
482
483static void
484taskqueue_run_drv(void *arg)
485{
486 struct task *task, *tmp;
487 struct task_head current;
488 int restarts = 0;
489 struct taskqueue *queue = (struct taskqueue *) arg;
490
491 STAILQ_INIT(¤t);
492 /*
493 * First we move all of the tasks off of the taskqueue's list
494 * on to current on the stack to avoided repeated serialization
495 */
496 mtx_lock_spin(&queue->tq_mutex);
497 queue->tq_flags |= TQ_FLAGS_RUNNING;
498restart:
499 STAILQ_CONCAT(¤t, &queue->tq_queue);
500 STAILQ_FOREACH(task, ¤t, ta_link) {
501 /*
502 * to let taskqueue_enqueue_fast know that this task
503 * has been dequeued but is referenced
504 * clear pending so that if pending is later set we know that it
505 * it needs to be re-enqueued even if the task doesn't return
506 * TA_NO_DEQUEUE
507 */
508 task->ta_ppending = task->ta_pending;
509 task->ta_pending = 0;
510 task->ta_flags |= TA_REFERENCED;
511 }
512 mtx_unlock_spin(&queue->tq_mutex);
513 STAILQ_FOREACH(task, ¤t, ta_link) {
514 task->ta_rc = task->ta_drv_func(task->ta_context, task->ta_ppending);
515
516 }
517 /*
518 * We've gotten here so we know that we've run the tasks that were
519 * on the taskqueue list on the first pass
520 */
521 mtx_lock_spin(&queue->tq_mutex);
522 STAILQ_FOREACH_SAFE(task, ¤t, ta_link, tmp) {
523 if (task->ta_rc != TA_NO_DEQUEUE && task->ta_pending == 0) {
524 STAILQ_REMOVE(¤t, task, task, ta_link);
525 task->ta_flags &= ~TA_REFERENCED;
526 }
527 task->ta_ppending = 0;
528 task->ta_rc = 0;
529 }
530 /*
531 * restart if there are any tasks in the list
532 */
533 if (STAILQ_FIRST(¤t) || STAILQ_FIRST(&queue->tq_queue)) {
534 restarts++;
535 goto restart;
536 }
537 queue->tq_flags &= ~TQ_FLAGS_RUNNING;
538 mtx_unlock_spin(&queue->tq_mutex);
539 CTR2(KTR_INTR, "queue=%s returning from taskqueue_run_drv after %d restarts", queue->tq_name, restarts);
540}
541
542static void
543taskqueue_drv_schedule(void *context)
544{
545 swi_sched(context, 0);
546}
547
548struct taskqueue *
549taskqueue_define_drv(void *arg, const char *name)
550{
551 struct taskqueue *tq;
552 struct thread *td;
553
554 tq = malloc(sizeof(struct taskqueue), M_TASKQUEUE,
555 M_NOWAIT | M_ZERO);
556 if (!tq) {
557 printf("%s: Unable to allocate fast drv task queue!\n",
558 __func__);
559 return (NULL);
560 }
561
562 STAILQ_INIT(&tq->tq_queue);
563 tq->tq_name = name;
564 tq->tq_enqueue = taskqueue_drv_schedule;
565 tq->tq_flags = (TQ_FLAGS_ACTIVE | TQ_FLAGS_SPIN | TQ_FLAGS_NOWAKEUP);
566 mtx_init(&tq->tq_mutex, name, NULL, MTX_SPIN);
567
568 mtx_lock(&taskqueue_queues_mutex);
569 STAILQ_INSERT_TAIL(&taskqueue_queues, tq, tq_link);
570 mtx_unlock(&taskqueue_queues_mutex);
571
572 swi_add(NULL, name, taskqueue_run_drv,
573 tq, SWI_NET, INTR_MPSAFE, &tq->tq_context);
574 td = intr_handler_thread((struct intr_handler *) tq->tq_context);
575 return (tq);
576}
577
578struct intr_handler *
579taskqueue_drv_handler(struct taskqueue *tq)
580{
581 return ((struct intr_handler *) tq->tq_context);
582}
583
584struct thread *
585taskqueue_drv_thread(void *context)
586{
587 struct taskqueue *tq = (struct taskqueue *) context;
588
589 return (intr_handler_thread((struct intr_handler *) tq->tq_context));
590}
591
592/*
593 * Caller must make sure that there must not be any new tasks getting queued
594 * before calling this.
595 */
596void
597taskqueue_free_drv(struct taskqueue *queue)
598{
599 struct intr_thread *ithd;
600 struct intr_event *ie;
601
602 mtx_lock(&taskqueue_queues_mutex);
603 STAILQ_REMOVE(&taskqueue_queues, queue, taskqueue, tq_link);
604 mtx_unlock(&taskqueue_queues_mutex);
605
606 ie = ((struct intr_handler *)(queue->tq_context))->ih_event;
607 ithd = ie->ie_thread;
608 swi_remove(queue->tq_context);
609 intr_event_destroy(ie);
610
611 mtx_lock_spin(&queue->tq_mutex);
612 taskqueue_run(queue);
613 mtx_destroy(&queue->tq_mutex);
614 free(queue, M_TASKQUEUE);
615}
616