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.
29 #include <sys/zfs_context.h>
32 taskq_t *system_taskq;
34 #define TASKQ_ACTIVE 0x00010000
38 krwlock_t tq_threadlock;
39 kcondvar_t tq_dispatch_cv;
40 kcondvar_t tq_wait_cv;
41 kthread_t **tq_threadlist;
48 kcondvar_t tq_maxalloc_cv;
50 taskq_ent_t *tq_freelist;
55 task_alloc(taskq_t *tq, int tqflags)
60 again: if ((t = tq->tq_freelist) != NULL && tq->tq_nalloc >= tq->tq_minalloc) {
61 ASSERT(!(t->tqent_flags & TQENT_FLAG_PREALLOC));
62 tq->tq_freelist = t->tqent_next;
64 if (tq->tq_nalloc >= tq->tq_maxalloc) {
65 if (!(tqflags & KM_SLEEP))
69 * We don't want to exceed tq_maxalloc, but we can't
70 * wait for other tasks to complete (and thus free up
71 * task structures) without risking deadlock with
72 * the caller. So, we just delay for one second
73 * to throttle the allocation rate. If we have tasks
74 * complete before one second timeout expires then
75 * taskq_ent_free will signal us and we will
76 * immediately retry the allocation.
78 tq->tq_maxalloc_wait++;
79 rv = cv_timedwait(&tq->tq_maxalloc_cv,
80 &tq->tq_lock, ddi_get_lbolt() + hz);
81 tq->tq_maxalloc_wait--;
83 goto again; /* signaled */
85 mutex_exit(&tq->tq_lock);
87 t = kmem_alloc(sizeof (taskq_ent_t), tqflags);
89 mutex_enter(&tq->tq_lock);
91 /* Make sure we start without any flags */
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 ASSERT(!(t->tqent_flags & TQENT_FLAG_PREALLOC));
146 cv_signal(&tq->tq_dispatch_cv);
147 mutex_exit(&tq->tq_lock);
152 taskq_empty_ent(taskq_ent_t *t)
154 return t->tqent_next == NULL;
158 taskq_init_ent(taskq_ent_t *t)
160 t->tqent_next = NULL;
161 t->tqent_prev = NULL;
162 t->tqent_func = NULL;
168 taskq_dispatch_ent(taskq_t *tq, task_func_t func, void *arg, uint_t flags,
171 ASSERT(func != NULL);
172 ASSERT(!(tq->tq_flags & TASKQ_DYNAMIC));
175 * Mark it as a prealloc'd task. This is important
176 * to ensure that we don't free it later.
178 t->tqent_flags |= TQENT_FLAG_PREALLOC;
180 * Enqueue the task to the underlying queue.
182 mutex_enter(&tq->tq_lock);
184 if (flags & TQ_FRONT) {
185 t->tqent_next = tq->tq_task.tqent_next;
186 t->tqent_prev = &tq->tq_task;
188 t->tqent_next = &tq->tq_task;
189 t->tqent_prev = tq->tq_task.tqent_prev;
191 t->tqent_next->tqent_prev = t;
192 t->tqent_prev->tqent_next = t;
193 t->tqent_func = func;
195 cv_signal(&tq->tq_dispatch_cv);
196 mutex_exit(&tq->tq_lock);
200 taskq_wait(taskq_t *tq)
202 mutex_enter(&tq->tq_lock);
203 while (tq->tq_task.tqent_next != &tq->tq_task || tq->tq_active != 0)
204 cv_wait(&tq->tq_wait_cv, &tq->tq_lock);
205 mutex_exit(&tq->tq_lock);
209 taskq_thread(void *arg)
215 mutex_enter(&tq->tq_lock);
216 while (tq->tq_flags & TASKQ_ACTIVE) {
217 if ((t = tq->tq_task.tqent_next) == &tq->tq_task) {
218 if (--tq->tq_active == 0)
219 cv_broadcast(&tq->tq_wait_cv);
220 cv_wait(&tq->tq_dispatch_cv, &tq->tq_lock);
224 t->tqent_prev->tqent_next = t->tqent_next;
225 t->tqent_next->tqent_prev = t->tqent_prev;
226 t->tqent_next = NULL;
227 t->tqent_prev = NULL;
228 prealloc = t->tqent_flags & TQENT_FLAG_PREALLOC;
229 mutex_exit(&tq->tq_lock);
231 rw_enter(&tq->tq_threadlock, RW_READER);
232 t->tqent_func(t->tqent_arg);
233 rw_exit(&tq->tq_threadlock);
235 mutex_enter(&tq->tq_lock);
240 cv_broadcast(&tq->tq_wait_cv);
241 mutex_exit(&tq->tq_lock);
247 taskq_create(const char *name, int nthreads, pri_t pri,
248 int minalloc, int maxalloc, uint_t flags)
250 taskq_t *tq = kmem_zalloc(sizeof (taskq_t), KM_SLEEP);
253 if (flags & TASKQ_THREADS_CPU_PCT) {
255 ASSERT3S(nthreads, >=, 0);
256 ASSERT3S(nthreads, <=, 100);
257 pct = MIN(nthreads, 100);
260 nthreads = (sysconf(_SC_NPROCESSORS_ONLN) * pct) / 100;
261 nthreads = MAX(nthreads, 1); /* need at least 1 thread */
263 ASSERT3S(nthreads, >=, 1);
266 rw_init(&tq->tq_threadlock, NULL, RW_DEFAULT, NULL);
267 mutex_init(&tq->tq_lock, NULL, MUTEX_DEFAULT, NULL);
268 cv_init(&tq->tq_dispatch_cv, NULL, CV_DEFAULT, NULL);
269 cv_init(&tq->tq_wait_cv, NULL, CV_DEFAULT, NULL);
270 cv_init(&tq->tq_maxalloc_cv, NULL, CV_DEFAULT, NULL);
271 tq->tq_flags = flags | TASKQ_ACTIVE;
272 tq->tq_active = nthreads;
273 tq->tq_nthreads = nthreads;
274 tq->tq_minalloc = minalloc;
275 tq->tq_maxalloc = maxalloc;
276 tq->tq_task.tqent_next = &tq->tq_task;
277 tq->tq_task.tqent_prev = &tq->tq_task;
278 tq->tq_threadlist = kmem_alloc(nthreads*sizeof(kthread_t *), KM_SLEEP);
280 if (flags & TASKQ_PREPOPULATE) {
281 mutex_enter(&tq->tq_lock);
282 while (minalloc-- > 0)
283 task_free(tq, task_alloc(tq, KM_SLEEP));
284 mutex_exit(&tq->tq_lock);
287 for (t = 0; t < nthreads; t++)
288 VERIFY((tq->tq_threadlist[t] = thread_create(NULL, 0,
289 taskq_thread, tq, TS_RUN, NULL, 0, 0)) != NULL);
295 taskq_destroy(taskq_t *tq)
297 int nthreads = tq->tq_nthreads;
301 mutex_enter(&tq->tq_lock);
303 tq->tq_flags &= ~TASKQ_ACTIVE;
304 cv_broadcast(&tq->tq_dispatch_cv);
306 while (tq->tq_nthreads != 0)
307 cv_wait(&tq->tq_wait_cv, &tq->tq_lock);
310 while (tq->tq_nalloc != 0) {
311 ASSERT(tq->tq_freelist != NULL);
312 task_free(tq, task_alloc(tq, KM_SLEEP));
315 mutex_exit(&tq->tq_lock);
317 kmem_free(tq->tq_threadlist, nthreads * sizeof (kthread_t *));
319 rw_destroy(&tq->tq_threadlock);
320 mutex_destroy(&tq->tq_lock);
321 cv_destroy(&tq->tq_dispatch_cv);
322 cv_destroy(&tq->tq_wait_cv);
323 cv_destroy(&tq->tq_maxalloc_cv);
325 kmem_free(tq, sizeof (taskq_t));
329 taskq_member(taskq_t *tq, kthread_t *t)
336 for (i = 0; i < tq->tq_nthreads; i++)
337 if (tq->tq_threadlist[i] == t)
344 system_taskq_init(void)
346 system_taskq = taskq_create("system_taskq", 64, minclsyspri, 4, 512,
347 TASKQ_DYNAMIC | TASKQ_PREPOPULATE);
351 system_taskq_fini(void)
353 taskq_destroy(system_taskq);
354 system_taskq = NULL; /* defensive */