4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
22 * Copyright 2010 Sun Microsystems, Inc. All rights reserved.
23 * Use is subject to license terms.
26 * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
27 * Copyright 2012 Garrett D'Amore <garrett@damore.org>. All rights reserved.
28 * Copyright (c) 2014 by Delphix. All rights reserved.
31 #include <sys/zfs_context.h>
34 taskq_t *system_taskq;
36 #define TASKQ_ACTIVE 0x00010000
37 #define TASKQ_NAMELEN 31
40 char tq_name[TASKQ_NAMELEN + 1];
42 krwlock_t tq_threadlock;
43 kcondvar_t tq_dispatch_cv;
44 kcondvar_t tq_wait_cv;
45 thread_t *tq_threadlist;
52 kcondvar_t tq_maxalloc_cv;
54 taskq_ent_t *tq_freelist;
59 task_alloc(taskq_t *tq, int tqflags)
64 again: if ((t = tq->tq_freelist) != NULL && tq->tq_nalloc >= tq->tq_minalloc) {
65 tq->tq_freelist = t->tqent_next;
67 if (tq->tq_nalloc >= tq->tq_maxalloc) {
68 if (!(tqflags & KM_SLEEP))
72 * We don't want to exceed tq_maxalloc, but we can't
73 * wait for other tasks to complete (and thus free up
74 * task structures) without risking deadlock with
75 * the caller. So, we just delay for one second
76 * to throttle the allocation rate. If we have tasks
77 * complete before one second timeout expires then
78 * taskq_ent_free will signal us and we will
79 * immediately retry the allocation.
81 tq->tq_maxalloc_wait++;
82 rv = cv_timedwait(&tq->tq_maxalloc_cv,
83 &tq->tq_lock, ddi_get_lbolt() + hz);
84 tq->tq_maxalloc_wait--;
86 goto again; /* signaled */
88 mutex_exit(&tq->tq_lock);
90 t = kmem_alloc(sizeof (taskq_ent_t), tqflags & KM_SLEEP);
92 mutex_enter(&tq->tq_lock);
100 task_free(taskq_t *tq, taskq_ent_t *t)
102 if (tq->tq_nalloc <= tq->tq_minalloc) {
103 t->tqent_next = tq->tq_freelist;
107 mutex_exit(&tq->tq_lock);
108 kmem_free(t, sizeof (taskq_ent_t));
109 mutex_enter(&tq->tq_lock);
112 if (tq->tq_maxalloc_wait)
113 cv_signal(&tq->tq_maxalloc_cv);
117 taskq_dispatch(taskq_t *tq, task_func_t func, void *arg, uint_t tqflags)
126 mutex_enter(&tq->tq_lock);
127 ASSERT(tq->tq_flags & TASKQ_ACTIVE);
128 if ((t = task_alloc(tq, tqflags)) == NULL) {
129 mutex_exit(&tq->tq_lock);
132 if (tqflags & TQ_FRONT) {
133 t->tqent_next = tq->tq_task.tqent_next;
134 t->tqent_prev = &tq->tq_task;
136 t->tqent_next = &tq->tq_task;
137 t->tqent_prev = tq->tq_task.tqent_prev;
139 t->tqent_next->tqent_prev = t;
140 t->tqent_prev->tqent_next = t;
141 t->tqent_func = func;
144 cv_signal(&tq->tq_dispatch_cv);
145 mutex_exit(&tq->tq_lock);
150 taskq_dispatch_ent(taskq_t *tq, task_func_t func, void *arg, uint_t flags,
153 ASSERT(func != NULL);
154 ASSERT(!(tq->tq_flags & TASKQ_DYNAMIC));
157 * Mark it as a prealloc'd task. This is important
158 * to ensure that we don't free it later.
160 t->tqent_flags |= TQENT_FLAG_PREALLOC;
162 * Enqueue the task to the underlying queue.
164 mutex_enter(&tq->tq_lock);
166 if (flags & TQ_FRONT) {
167 t->tqent_next = tq->tq_task.tqent_next;
168 t->tqent_prev = &tq->tq_task;
170 t->tqent_next = &tq->tq_task;
171 t->tqent_prev = tq->tq_task.tqent_prev;
173 t->tqent_next->tqent_prev = t;
174 t->tqent_prev->tqent_next = t;
175 t->tqent_func = func;
177 cv_signal(&tq->tq_dispatch_cv);
178 mutex_exit(&tq->tq_lock);
182 taskq_wait(taskq_t *tq)
184 mutex_enter(&tq->tq_lock);
185 while (tq->tq_task.tqent_next != &tq->tq_task || tq->tq_active != 0)
186 cv_wait(&tq->tq_wait_cv, &tq->tq_lock);
187 mutex_exit(&tq->tq_lock);
191 taskq_thread(void *arg)
197 mutex_enter(&tq->tq_lock);
198 while (tq->tq_flags & TASKQ_ACTIVE) {
199 if ((t = tq->tq_task.tqent_next) == &tq->tq_task) {
200 if (--tq->tq_active == 0)
201 cv_broadcast(&tq->tq_wait_cv);
202 cv_wait(&tq->tq_dispatch_cv, &tq->tq_lock);
206 t->tqent_prev->tqent_next = t->tqent_next;
207 t->tqent_next->tqent_prev = t->tqent_prev;
208 t->tqent_next = NULL;
209 t->tqent_prev = NULL;
210 prealloc = t->tqent_flags & TQENT_FLAG_PREALLOC;
211 mutex_exit(&tq->tq_lock);
213 rw_enter(&tq->tq_threadlock, RW_READER);
214 t->tqent_func(t->tqent_arg);
215 rw_exit(&tq->tq_threadlock);
217 mutex_enter(&tq->tq_lock);
222 cv_broadcast(&tq->tq_wait_cv);
223 mutex_exit(&tq->tq_lock);
229 taskq_create(const char *name, int nthreads, pri_t pri,
230 int minalloc, int maxalloc, uint_t flags)
232 taskq_t *tq = kmem_zalloc(sizeof (taskq_t), KM_SLEEP);
235 if (flags & TASKQ_THREADS_CPU_PCT) {
237 ASSERT3S(nthreads, >=, 0);
238 ASSERT3S(nthreads, <=, 100);
239 pct = MIN(nthreads, 100);
242 nthreads = (sysconf(_SC_NPROCESSORS_ONLN) * pct) / 100;
243 nthreads = MAX(nthreads, 1); /* need at least 1 thread */
245 ASSERT3S(nthreads, >=, 1);
248 rw_init(&tq->tq_threadlock, NULL, RW_DEFAULT, NULL);
249 mutex_init(&tq->tq_lock, NULL, MUTEX_DEFAULT, NULL);
250 cv_init(&tq->tq_dispatch_cv, NULL, CV_DEFAULT, NULL);
251 cv_init(&tq->tq_wait_cv, NULL, CV_DEFAULT, NULL);
252 cv_init(&tq->tq_maxalloc_cv, NULL, CV_DEFAULT, NULL);
253 (void) strncpy(tq->tq_name, name, TASKQ_NAMELEN + 1);
254 tq->tq_flags = flags | TASKQ_ACTIVE;
255 tq->tq_active = nthreads;
256 tq->tq_nthreads = nthreads;
257 tq->tq_minalloc = minalloc;
258 tq->tq_maxalloc = maxalloc;
259 tq->tq_task.tqent_next = &tq->tq_task;
260 tq->tq_task.tqent_prev = &tq->tq_task;
261 tq->tq_threadlist = kmem_alloc(nthreads * sizeof (thread_t), KM_SLEEP);
263 if (flags & TASKQ_PREPOPULATE) {
264 mutex_enter(&tq->tq_lock);
265 while (minalloc-- > 0)
266 task_free(tq, task_alloc(tq, KM_SLEEP));
267 mutex_exit(&tq->tq_lock);
270 for (t = 0; t < nthreads; t++)
271 (void) thr_create(0, 0, taskq_thread,
272 tq, THR_BOUND, &tq->tq_threadlist[t]);
278 taskq_destroy(taskq_t *tq)
281 int nthreads = tq->tq_nthreads;
285 mutex_enter(&tq->tq_lock);
287 tq->tq_flags &= ~TASKQ_ACTIVE;
288 cv_broadcast(&tq->tq_dispatch_cv);
290 while (tq->tq_nthreads != 0)
291 cv_wait(&tq->tq_wait_cv, &tq->tq_lock);
294 while (tq->tq_nalloc != 0) {
295 ASSERT(tq->tq_freelist != NULL);
296 task_free(tq, task_alloc(tq, KM_SLEEP));
299 mutex_exit(&tq->tq_lock);
301 for (t = 0; t < nthreads; t++)
302 (void) thr_join(tq->tq_threadlist[t], NULL, NULL);
304 kmem_free(tq->tq_threadlist, nthreads * sizeof (thread_t));
306 rw_destroy(&tq->tq_threadlock);
307 mutex_destroy(&tq->tq_lock);
308 cv_destroy(&tq->tq_dispatch_cv);
309 cv_destroy(&tq->tq_wait_cv);
310 cv_destroy(&tq->tq_maxalloc_cv);
312 kmem_free(tq, sizeof (taskq_t));
316 taskq_member(taskq_t *tq, void *t)
323 for (i = 0; i < tq->tq_nthreads; i++)
324 if (tq->tq_threadlist[i] == (thread_t)(uintptr_t)t)
331 system_taskq_init(void)
333 system_taskq = taskq_create("system_taskq", 64, minclsyspri, 4, 512,
334 TASKQ_DYNAMIC | TASKQ_PREPOPULATE);
338 system_taskq_fini(void)
340 taskq_destroy(system_taskq);
341 system_taskq = NULL; /* defensive */