1 /*-
2 * Copyright (c) 2000 Doug Rabson
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
29
30 #include <sys/param.h>
31 #include <sys/systm.h>
32 #include <sys/bus.h>
33 #include <sys/interrupt.h>
34 #include <sys/kernel.h>
35 #include <sys/kthread.h>
36 #include <sys/lock.h>
37 #include <sys/malloc.h>
38 #include <sys/mutex.h>
39 #include <sys/proc.h>
40 #include <sys/sched.h>
41 #include <sys/taskqueue.h>
42 #include <sys/unistd.h>
43 #include <machine/stdarg.h>
44
45 static MALLOC_DEFINE(M_TASKQUEUE, "taskqueue", "Task Queues");
46 static void *taskqueue_giant_ih;
47 static void *taskqueue_ih;
48 static STAILQ_HEAD(taskqueue_list, taskqueue) taskqueue_queues;
49 static struct mtx taskqueue_queues_mutex;
50
51 struct taskqueue {
52 STAILQ_ENTRY(taskqueue) tq_link;
53 STAILQ_HEAD(, task) tq_queue;
54 const char *tq_name;
55 taskqueue_enqueue_fn tq_enqueue;
56 void *tq_context;
57 struct task *tq_running;
58 struct mtx tq_mutex;
59 struct proc **tq_pproc;
60 int tq_pcount;
61 int tq_spin;
62 int tq_flags;
63 };
64
65 #define TQ_FLAGS_ACTIVE (1 << 0)
66 #define TQ_FLAGS_BLOCKED (1 << 1)
67 #define TQ_FLAGS_PENDING (1 << 2)
68
69 static __inline void
70 TQ_LOCK(struct taskqueue *tq)
71 {
72 if (tq->tq_spin)
73 mtx_lock_spin(&tq->tq_mutex);
74 else
75 mtx_lock(&tq->tq_mutex);
76 }
77
78 static __inline void
79 TQ_UNLOCK(struct taskqueue *tq)
80 {
81 if (tq->tq_spin)
82 mtx_unlock_spin(&tq->tq_mutex);
83 else
84 mtx_unlock(&tq->tq_mutex);
85 }
86
87 static void init_taskqueue_list(void *data);
88
89 static __inline int
90 TQ_SLEEP(struct taskqueue *tq, void *p, struct mtx *m, int pri, const char *wm,
91 int t)
92 {
93 if (tq->tq_spin)
94 return (msleep_spin(p, m, wm, t));
95 return (msleep(p, m, pri, wm, t));
96 }
97
98 static void
99 init_taskqueue_list(void *data __unused)
100 {
101
102 mtx_init(&taskqueue_queues_mutex, "taskqueue list", NULL, MTX_DEF);
103 STAILQ_INIT(&taskqueue_queues);
104 }
105 SYSINIT(taskqueue_list, SI_SUB_INTRINSIC, SI_ORDER_ANY, init_taskqueue_list,
106 NULL);
107
108 static struct taskqueue *
109 _taskqueue_create(const char *name, int mflags,
110 taskqueue_enqueue_fn enqueue, void *context,
111 int mtxflags, const char *mtxname)
112 {
113 struct taskqueue *queue;
114
115 queue = malloc(sizeof(struct taskqueue), M_TASKQUEUE, mflags | M_ZERO);
116 if (!queue)
117 return 0;
118
119 STAILQ_INIT(&queue->tq_queue);
120 queue->tq_name = name;
121 queue->tq_enqueue = enqueue;
122 queue->tq_context = context;
123 queue->tq_spin = (mtxflags & MTX_SPIN) != 0;
124 queue->tq_flags |= TQ_FLAGS_ACTIVE;
125 mtx_init(&queue->tq_mutex, mtxname, NULL, mtxflags);
126
127 mtx_lock(&taskqueue_queues_mutex);
128 STAILQ_INSERT_TAIL(&taskqueue_queues, queue, tq_link);
129 mtx_unlock(&taskqueue_queues_mutex);
130
131 return queue;
132 }
133
134 struct taskqueue *
135 taskqueue_create(const char *name, int mflags,
136 taskqueue_enqueue_fn enqueue, void *context)
137 {
138 return _taskqueue_create(name, mflags, enqueue, context,
139 MTX_DEF, "taskqueue");
140 }
141
142 /*
143 * Signal a taskqueue thread to terminate.
144 */
145 static void
146 taskqueue_terminate(struct proc **pp, struct taskqueue *tq)
147 {
148
149 while (tq->tq_pcount > 0) {
150 wakeup(tq);
151 TQ_SLEEP(tq, pp, &tq->tq_mutex, PWAIT, "taskqueue_destroy", 0);
152 }
153 }
154
155 void
156 taskqueue_free(struct taskqueue *queue)
157 {
158
159 mtx_lock(&taskqueue_queues_mutex);
160 STAILQ_REMOVE(&taskqueue_queues, queue, taskqueue, tq_link);
161 mtx_unlock(&taskqueue_queues_mutex);
162
163 TQ_LOCK(queue);
164 queue->tq_flags &= ~TQ_FLAGS_ACTIVE;
165 taskqueue_run(queue);
166 taskqueue_terminate(queue->tq_pproc, queue);
167 mtx_destroy(&queue->tq_mutex);
168 free(queue->tq_pproc, M_TASKQUEUE);
169 free(queue, M_TASKQUEUE);
170 }
171
172 /*
173 * Returns with the taskqueue locked.
174 */
175 struct taskqueue *
176 taskqueue_find(const char *name)
177 {
178 struct taskqueue *queue;
179
180 mtx_lock(&taskqueue_queues_mutex);
181 STAILQ_FOREACH(queue, &taskqueue_queues, tq_link) {
182 if (strcmp(queue->tq_name, name) == 0) {
183 TQ_LOCK(queue);
184 mtx_unlock(&taskqueue_queues_mutex);
185 return queue;
186 }
187 }
188 mtx_unlock(&taskqueue_queues_mutex);
189 return NULL;
190 }
191
192 int
193 taskqueue_enqueue(struct taskqueue *queue, struct task *task)
194 {
195 struct task *ins;
196 struct task *prev;
197
198 TQ_LOCK(queue);
199
200 /*
201 * Count multiple enqueues.
202 */
203 if (task->ta_pending) {
204 task->ta_pending++;
205 TQ_UNLOCK(queue);
206 return 0;
207 }
208
209 /*
210 * Optimise the case when all tasks have the same priority.
211 */
212 prev = STAILQ_LAST(&queue->tq_queue, task, ta_link);
213 if (!prev || prev->ta_priority >= task->ta_priority) {
214 STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link);
215 } else {
216 prev = 0;
217 for (ins = STAILQ_FIRST(&queue->tq_queue); ins;
218 prev = ins, ins = STAILQ_NEXT(ins, ta_link))
219 if (ins->ta_priority < task->ta_priority)
220 break;
221
222 if (prev)
223 STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link);
224 else
225 STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link);
226 }
227
228 task->ta_pending = 1;
229 if ((queue->tq_flags & TQ_FLAGS_BLOCKED) == 0)
230 queue->tq_enqueue(queue->tq_context);
231 else
232 queue->tq_flags |= TQ_FLAGS_PENDING;
233
234 TQ_UNLOCK(queue);
235
236 return 0;
237 }
238
239 void
240 taskqueue_block(struct taskqueue *queue)
241 {
242
243 TQ_LOCK(queue);
244 queue->tq_flags |= TQ_FLAGS_BLOCKED;
245 TQ_UNLOCK(queue);
246 }
247
248 void
249 taskqueue_unblock(struct taskqueue *queue)
250 {
251
252 TQ_LOCK(queue);
253 queue->tq_flags &= ~TQ_FLAGS_BLOCKED;
254 if (queue->tq_flags & TQ_FLAGS_PENDING) {
255 queue->tq_flags &= ~TQ_FLAGS_PENDING;
256 queue->tq_enqueue(queue->tq_context);
257 }
258 TQ_UNLOCK(queue);
259 }
260
261 void
262 taskqueue_run(struct taskqueue *queue)
263 {
264 struct task *task;
265 int owned, pending;
266
267 owned = mtx_owned(&queue->tq_mutex);
268 if (!owned)
269 TQ_LOCK(queue);
270 while (STAILQ_FIRST(&queue->tq_queue)) {
271 /*
272 * Carefully remove the first task from the queue and
273 * zero its pending count.
274 */
275 task = STAILQ_FIRST(&queue->tq_queue);
276 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link);
277 pending = task->ta_pending;
278 task->ta_pending = 0;
279 queue->tq_running = task;
280 TQ_UNLOCK(queue);
281
282 task->ta_func(task->ta_context, pending);
283
284 TQ_LOCK(queue);
285 queue->tq_running = NULL;
286 wakeup(task);
287 }
288
289 /*
290 * For compatibility, unlock on return if the queue was not locked
291 * on entry, although this opens a race window.
292 */
293 if (!owned)
294 TQ_UNLOCK(queue);
295 }
296
297 void
298 taskqueue_drain(struct taskqueue *queue, struct task *task)
299 {
300 if (queue->tq_spin) { /* XXX */
301 mtx_lock_spin(&queue->tq_mutex);
302 while (task->ta_pending != 0 || task == queue->tq_running)
303 msleep_spin(task, &queue->tq_mutex, "-", 0);
304 mtx_unlock_spin(&queue->tq_mutex);
305 } else {
306 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
307
308 mtx_lock(&queue->tq_mutex);
309 while (task->ta_pending != 0 || task == queue->tq_running)
310 msleep(task, &queue->tq_mutex, PWAIT, "-", 0);
311 mtx_unlock(&queue->tq_mutex);
312 }
313 }
314
315 static void
316 taskqueue_swi_enqueue(void *context)
317 {
318 swi_sched(taskqueue_ih, 0);
319 }
320
321 static void
322 taskqueue_swi_run(void *dummy)
323 {
324 taskqueue_run(taskqueue_swi);
325 }
326
327 static void
328 taskqueue_swi_giant_enqueue(void *context)
329 {
330 swi_sched(taskqueue_giant_ih, 0);
331 }
332
333 static void
334 taskqueue_swi_giant_run(void *dummy)
335 {
336 taskqueue_run(taskqueue_swi_giant);
337 }
338
339 int
340 taskqueue_start_threads(struct taskqueue **tqp, int count, int pri,
341 const char *name, ...)
342 {
343 va_list ap;
344 struct taskqueue *tq;
345 struct thread *td;
346 char ktname[MAXCOMLEN];
347 int i, error;
348
349 if (count <= 0)
350 return (EINVAL);
351 tq = *tqp;
352
353 va_start(ap, name);
354 vsnprintf(ktname, MAXCOMLEN, name, ap);
355 va_end(ap);
356
357 tq->tq_pproc = malloc(sizeof(struct proc *) * count, M_TASKQUEUE,
358 M_NOWAIT | M_ZERO);
359 if (tq->tq_pproc == NULL) {
360 printf("%s: no memory for %s threads\n", __func__, ktname);
361 return (ENOMEM);
362 }
363
364 for (i = 0; i < count; i++) {
365 if (count == 1)
366 error = kthread_create(taskqueue_thread_loop, tqp,
367 &tq->tq_pproc[i], RFSTOPPED, 0, ktname);
368 else
369 error = kthread_create(taskqueue_thread_loop, tqp,
370 &tq->tq_pproc[i], RFSTOPPED, 0, "%s_%d", ktname, i);
371 if (error) {
372 /* should be ok to continue, taskqueue_free will dtrt */
373 printf("%s: kthread_create(%s): error %d",
374 __func__, ktname, error);
375 tq->tq_pproc[i] = NULL; /* paranoid */
376 } else
377 tq->tq_pcount++;
378 }
379 for (i = 0; i < count; i++) {
380 if (tq->tq_pproc[i] == NULL)
381 continue;
382 td = FIRST_THREAD_IN_PROC(tq->tq_pproc[i]);
383 thread_lock(td);
384 sched_prio(td, pri);
385 sched_add(td, SRQ_BORING);
386 thread_unlock(td);
387 }
388
389 return (0);
390 }
391
392 void
393 taskqueue_thread_loop(void *arg)
394 {
395 struct taskqueue **tqp, *tq;
396
397 tqp = arg;
398 tq = *tqp;
399 TQ_LOCK(tq);
400 while ((tq->tq_flags & TQ_FLAGS_ACTIVE) != 0) {
401 taskqueue_run(tq);
402 TQ_SLEEP(tq, tq, &tq->tq_mutex, 0, "-", 0);
403 }
404
405 /* rendezvous with thread that asked us to terminate */
406 tq->tq_pcount--;
407 wakeup_one(tq->tq_pproc);
408 TQ_UNLOCK(tq);
409 kthread_exit(0);
410 }
411
412 void
413 taskqueue_thread_enqueue(void *context)
414 {
415 struct taskqueue **tqp, *tq;
416
417 tqp = context;
418 tq = *tqp;
419
420 mtx_assert(&tq->tq_mutex, MA_OWNED);
421 wakeup_one(tq);
422 }
423
424 TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, 0,
425 swi_add(NULL, "task queue", taskqueue_swi_run, NULL, SWI_TQ,
426 INTR_MPSAFE, &taskqueue_ih));
427
428 TASKQUEUE_DEFINE(swi_giant, taskqueue_swi_giant_enqueue, 0,
429 swi_add(NULL, "Giant taskq", taskqueue_swi_giant_run,
430 NULL, SWI_TQ_GIANT, 0, &taskqueue_giant_ih));
431
432 TASKQUEUE_DEFINE_THREAD(thread);
433
434 struct taskqueue *
435 taskqueue_create_fast(const char *name, int mflags,
436 taskqueue_enqueue_fn enqueue, void *context)
437 {
438 return _taskqueue_create(name, mflags, enqueue, context,
439 MTX_SPIN, "fast_taskqueue");
440 }
441
442 /* NB: for backwards compatibility */
443 int
444 taskqueue_enqueue_fast(struct taskqueue *queue, struct task *task)
445 {
446 return taskqueue_enqueue(queue, task);
447 }
448
449 static void *taskqueue_fast_ih;
450
451 static void
452 taskqueue_fast_enqueue(void *context)
453 {
454 swi_sched(taskqueue_fast_ih, 0);
455 }
456
457 static void
458 taskqueue_fast_run(void *dummy)
459 {
460 taskqueue_run(taskqueue_fast);
461 }
462
463 TASKQUEUE_FAST_DEFINE(fast, taskqueue_fast_enqueue, 0,
464 swi_add(NULL, "Fast task queue", taskqueue_fast_run, NULL,
465 SWI_TQ_FAST, INTR_MPSAFE, &taskqueue_fast_ih));
Cache object: 4e368625eccc8cfaf671e3ba05f059b1
|