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: releng/6.1/sys/kern/subr_taskqueue.c 158179 2006-04-30 16:44:43Z cvs2svn $");
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/taskqueue.h>
41 #include <sys/unistd.h>
42
43 static MALLOC_DEFINE(M_TASKQUEUE, "taskqueue", "Task Queues");
44 static void *taskqueue_giant_ih;
45 static void *taskqueue_ih;
46 static STAILQ_HEAD(taskqueue_list, taskqueue) taskqueue_queues;
47 static struct mtx taskqueue_queues_mutex;
48
49 struct taskqueue {
50 STAILQ_ENTRY(taskqueue) tq_link;
51 STAILQ_HEAD(, task) tq_queue;
52 const char *tq_name;
53 taskqueue_enqueue_fn tq_enqueue;
54 void *tq_context;
55 struct task *tq_running;
56 struct mtx tq_mutex;
57 struct proc **tq_pproc;
58 };
59
60 static void init_taskqueue_list(void *data);
61
62 static void
63 init_taskqueue_list(void *data __unused)
64 {
65
66 mtx_init(&taskqueue_queues_mutex, "taskqueue list", NULL, MTX_DEF);
67 STAILQ_INIT(&taskqueue_queues);
68 }
69 SYSINIT(taskqueue_list, SI_SUB_INTRINSIC, SI_ORDER_ANY, init_taskqueue_list,
70 NULL);
71
72 struct taskqueue *
73 taskqueue_create(const char *name, int mflags,
74 taskqueue_enqueue_fn enqueue, void *context,
75 struct proc **pp)
76 {
77 struct taskqueue *queue;
78
79 queue = malloc(sizeof(struct taskqueue), M_TASKQUEUE, mflags | M_ZERO);
80 if (!queue)
81 return 0;
82
83 STAILQ_INIT(&queue->tq_queue);
84 queue->tq_name = name;
85 queue->tq_enqueue = enqueue;
86 queue->tq_context = context;
87 queue->tq_pproc = pp;
88 mtx_init(&queue->tq_mutex, "taskqueue", NULL, MTX_DEF);
89
90 mtx_lock(&taskqueue_queues_mutex);
91 STAILQ_INSERT_TAIL(&taskqueue_queues, queue, tq_link);
92 mtx_unlock(&taskqueue_queues_mutex);
93
94 return queue;
95 }
96
97 /*
98 * Signal a taskqueue thread to terminate.
99 */
100 static void
101 taskqueue_terminate(struct proc **pp, struct taskqueue *tq)
102 {
103 struct proc *p;
104
105 p = *pp;
106 *pp = NULL;
107 if (p) {
108 wakeup_one(tq);
109 PROC_LOCK(p); /* NB: insure we don't miss wakeup */
110 mtx_unlock(&tq->tq_mutex); /* let taskqueue thread run */
111 msleep(p, &p->p_mtx, PWAIT, "taskqueue_destroy", 0);
112 PROC_UNLOCK(p);
113 mtx_lock(&tq->tq_mutex);
114 }
115 }
116
117 void
118 taskqueue_free(struct taskqueue *queue)
119 {
120
121 mtx_lock(&taskqueue_queues_mutex);
122 STAILQ_REMOVE(&taskqueue_queues, queue, taskqueue, tq_link);
123 mtx_unlock(&taskqueue_queues_mutex);
124
125 mtx_lock(&queue->tq_mutex);
126 taskqueue_run(queue);
127 taskqueue_terminate(queue->tq_pproc, queue);
128 mtx_destroy(&queue->tq_mutex);
129 free(queue, M_TASKQUEUE);
130 }
131
132 /*
133 * Returns with the taskqueue locked.
134 */
135 struct taskqueue *
136 taskqueue_find(const char *name)
137 {
138 struct taskqueue *queue;
139
140 mtx_lock(&taskqueue_queues_mutex);
141 STAILQ_FOREACH(queue, &taskqueue_queues, tq_link) {
142 if (strcmp(queue->tq_name, name) == 0) {
143 mtx_lock(&queue->tq_mutex);
144 mtx_unlock(&taskqueue_queues_mutex);
145 return queue;
146 }
147 }
148 mtx_unlock(&taskqueue_queues_mutex);
149 return NULL;
150 }
151
152 int
153 taskqueue_enqueue(struct taskqueue *queue, struct task *task)
154 {
155 struct task *ins;
156 struct task *prev;
157
158 mtx_lock(&queue->tq_mutex);
159
160 /*
161 * Count multiple enqueues.
162 */
163 if (task->ta_pending) {
164 task->ta_pending++;
165 mtx_unlock(&queue->tq_mutex);
166 return 0;
167 }
168
169 /*
170 * Optimise the case when all tasks have the same priority.
171 */
172 prev = STAILQ_LAST(&queue->tq_queue, task, ta_link);
173 if (!prev || prev->ta_priority >= task->ta_priority) {
174 STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link);
175 } else {
176 prev = 0;
177 for (ins = STAILQ_FIRST(&queue->tq_queue); ins;
178 prev = ins, ins = STAILQ_NEXT(ins, ta_link))
179 if (ins->ta_priority < task->ta_priority)
180 break;
181
182 if (prev)
183 STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link);
184 else
185 STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link);
186 }
187
188 task->ta_pending = 1;
189 queue->tq_enqueue(queue->tq_context);
190
191 mtx_unlock(&queue->tq_mutex);
192
193 return 0;
194 }
195
196 void
197 taskqueue_run(struct taskqueue *queue)
198 {
199 struct task *task;
200 int owned, pending;
201
202 owned = mtx_owned(&queue->tq_mutex);
203 if (!owned)
204 mtx_lock(&queue->tq_mutex);
205 while (STAILQ_FIRST(&queue->tq_queue)) {
206 /*
207 * Carefully remove the first task from the queue and
208 * zero its pending count.
209 */
210 task = STAILQ_FIRST(&queue->tq_queue);
211 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link);
212 pending = task->ta_pending;
213 task->ta_pending = 0;
214 queue->tq_running = task;
215 mtx_unlock(&queue->tq_mutex);
216
217 task->ta_func(task->ta_context, pending);
218
219 mtx_lock(&queue->tq_mutex);
220 queue->tq_running = NULL;
221 wakeup(task);
222 }
223
224 /*
225 * For compatibility, unlock on return if the queue was not locked
226 * on entry, although this opens a race window.
227 */
228 if (!owned)
229 mtx_unlock(&queue->tq_mutex);
230 }
231
232 void
233 taskqueue_drain(struct taskqueue *queue, struct task *task)
234 {
235 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, "taskqueue_drain");
236
237 mtx_lock(&queue->tq_mutex);
238 while (task->ta_pending != 0 || task == queue->tq_running)
239 msleep(task, &queue->tq_mutex, PWAIT, "-", 0);
240 mtx_unlock(&queue->tq_mutex);
241 }
242
243 static void
244 taskqueue_swi_enqueue(void *context)
245 {
246 swi_sched(taskqueue_ih, 0);
247 }
248
249 static void
250 taskqueue_swi_run(void *dummy)
251 {
252 taskqueue_run(taskqueue_swi);
253 }
254
255 static void
256 taskqueue_swi_giant_enqueue(void *context)
257 {
258 swi_sched(taskqueue_giant_ih, 0);
259 }
260
261 static void
262 taskqueue_swi_giant_run(void *dummy)
263 {
264 taskqueue_run(taskqueue_swi_giant);
265 }
266
267 void
268 taskqueue_thread_loop(void *arg)
269 {
270 struct taskqueue **tqp, *tq;
271
272 tqp = arg;
273 tq = *tqp;
274 mtx_lock(&tq->tq_mutex);
275 do {
276 taskqueue_run(tq);
277 msleep(tq, &tq->tq_mutex, PWAIT, "-", 0);
278 } while (*tq->tq_pproc != NULL);
279
280 /* rendezvous with thread that asked us to terminate */
281 wakeup_one(tq);
282 mtx_unlock(&tq->tq_mutex);
283 kthread_exit(0);
284 }
285
286 void
287 taskqueue_thread_enqueue(void *context)
288 {
289 struct taskqueue **tqp, *tq;
290
291 tqp = context;
292 tq = *tqp;
293
294 mtx_assert(&tq->tq_mutex, MA_OWNED);
295 wakeup_one(tq);
296 }
297
298 TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, 0,
299 swi_add(NULL, "task queue", taskqueue_swi_run, NULL, SWI_TQ,
300 INTR_MPSAFE, &taskqueue_ih));
301
302 TASKQUEUE_DEFINE(swi_giant, taskqueue_swi_giant_enqueue, 0,
303 swi_add(NULL, "Giant task queue", taskqueue_swi_giant_run,
304 NULL, SWI_TQ_GIANT, 0, &taskqueue_giant_ih));
305
306 TASKQUEUE_DEFINE_THREAD(thread);
307
308 int
309 taskqueue_enqueue_fast(struct taskqueue *queue, struct task *task)
310 {
311 struct task *ins;
312 struct task *prev;
313
314 mtx_lock_spin(&queue->tq_mutex);
315
316 /*
317 * Count multiple enqueues.
318 */
319 if (task->ta_pending) {
320 task->ta_pending++;
321 mtx_unlock_spin(&queue->tq_mutex);
322 return 0;
323 }
324
325 /*
326 * Optimise the case when all tasks have the same priority.
327 */
328 prev = STAILQ_LAST(&queue->tq_queue, task, ta_link);
329 if (!prev || prev->ta_priority >= task->ta_priority) {
330 STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link);
331 } else {
332 prev = 0;
333 for (ins = STAILQ_FIRST(&queue->tq_queue); ins;
334 prev = ins, ins = STAILQ_NEXT(ins, ta_link))
335 if (ins->ta_priority < task->ta_priority)
336 break;
337
338 if (prev)
339 STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link);
340 else
341 STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link);
342 }
343
344 task->ta_pending = 1;
345 queue->tq_enqueue(queue->tq_context);
346
347 mtx_unlock_spin(&queue->tq_mutex);
348
349 return 0;
350 }
351
352 static void
353 taskqueue_run_fast(struct taskqueue *queue)
354 {
355 struct task *task;
356 int pending;
357
358 mtx_lock_spin(&queue->tq_mutex);
359 while (STAILQ_FIRST(&queue->tq_queue)) {
360 /*
361 * Carefully remove the first task from the queue and
362 * zero its pending count.
363 */
364 task = STAILQ_FIRST(&queue->tq_queue);
365 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link);
366 pending = task->ta_pending;
367 task->ta_pending = 0;
368 mtx_unlock_spin(&queue->tq_mutex);
369
370 task->ta_func(task->ta_context, pending);
371
372 mtx_lock_spin(&queue->tq_mutex);
373 }
374 mtx_unlock_spin(&queue->tq_mutex);
375 }
376
377 struct taskqueue *taskqueue_fast;
378 static void *taskqueue_fast_ih;
379
380 static void
381 taskqueue_fast_schedule(void *context)
382 {
383 swi_sched(taskqueue_fast_ih, 0);
384 }
385
386 static void
387 taskqueue_fast_run(void *dummy)
388 {
389 taskqueue_run_fast(taskqueue_fast);
390 }
391
392 static void
393 taskqueue_define_fast(void *arg)
394 {
395
396 taskqueue_fast = malloc(sizeof(struct taskqueue), M_TASKQUEUE,
397 M_NOWAIT | M_ZERO);
398 if (!taskqueue_fast) {
399 printf("%s: Unable to allocate fast task queue!\n", __func__);
400 return;
401 }
402
403 STAILQ_INIT(&taskqueue_fast->tq_queue);
404 taskqueue_fast->tq_name = "fast";
405 taskqueue_fast->tq_enqueue = taskqueue_fast_schedule;
406 mtx_init(&taskqueue_fast->tq_mutex, "taskqueue_fast", NULL, MTX_SPIN);
407
408 mtx_lock(&taskqueue_queues_mutex);
409 STAILQ_INSERT_TAIL(&taskqueue_queues, taskqueue_fast, tq_link);
410 mtx_unlock(&taskqueue_queues_mutex);
411
412 swi_add(NULL, "Fast task queue", taskqueue_fast_run,
413 NULL, SWI_TQ_FAST, INTR_MPSAFE, &taskqueue_fast_ih);
414 }
415 SYSINIT(taskqueue_fast, SI_SUB_CONFIGURE, SI_ORDER_SECOND,
416 taskqueue_define_fast, NULL);
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