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.
30 #include <sys/zfs_context.h>
33 taskq_t *system_taskq;
35 #define TASKQ_ACTIVE 0x00010000
39 krwlock_t tq_threadlock;
40 kcondvar_t tq_dispatch_cv;
41 kcondvar_t tq_wait_cv;
42 kthread_t **tq_threadlist;
49 kcondvar_t tq_maxalloc_cv;
51 taskq_ent_t *tq_freelist;
56 task_alloc(taskq_t *tq, int tqflags)
61 again: if ((t = tq->tq_freelist) != NULL && tq->tq_nalloc >= tq->tq_minalloc) {
62 ASSERT(!(t->tqent_flags & TQENT_FLAG_PREALLOC));
63 tq->tq_freelist = t->tqent_next;
65 if (tq->tq_nalloc >= tq->tq_maxalloc) {
66 if (!(tqflags & KM_SLEEP))
70 * We don't want to exceed tq_maxalloc, but we can't
71 * wait for other tasks to complete (and thus free up
72 * task structures) without risking deadlock with
73 * the caller. So, we just delay for one second
74 * to throttle the allocation rate. If we have tasks
75 * complete before one second timeout expires then
76 * taskq_ent_free will signal us and we will
77 * immediately retry the allocation.
79 tq->tq_maxalloc_wait++;
80 rv = cv_timedwait(&tq->tq_maxalloc_cv,
81 &tq->tq_lock, ddi_get_lbolt() + hz);
82 tq->tq_maxalloc_wait--;
84 goto again; /* signaled */
86 mutex_exit(&tq->tq_lock);
88 t = kmem_alloc(sizeof (taskq_ent_t), tqflags);
90 mutex_enter(&tq->tq_lock);
92 /* Make sure we start without any flags */
101 task_free(taskq_t *tq, taskq_ent_t *t)
103 if (tq->tq_nalloc <= tq->tq_minalloc) {
104 t->tqent_next = tq->tq_freelist;
108 mutex_exit(&tq->tq_lock);
109 kmem_free(t, sizeof (taskq_ent_t));
110 mutex_enter(&tq->tq_lock);
113 if (tq->tq_maxalloc_wait)
114 cv_signal(&tq->tq_maxalloc_cv);
118 taskq_dispatch(taskq_t *tq, task_func_t func, void *arg, uint_t tqflags)
127 mutex_enter(&tq->tq_lock);
128 ASSERT(tq->tq_flags & TASKQ_ACTIVE);
129 if ((t = task_alloc(tq, tqflags)) == NULL) {
130 mutex_exit(&tq->tq_lock);
133 if (tqflags & TQ_FRONT) {
134 t->tqent_next = tq->tq_task.tqent_next;
135 t->tqent_prev = &tq->tq_task;
137 t->tqent_next = &tq->tq_task;
138 t->tqent_prev = tq->tq_task.tqent_prev;
140 t->tqent_next->tqent_prev = t;
141 t->tqent_prev->tqent_next = t;
142 t->tqent_func = func;
145 cv_signal(&tq->tq_dispatch_cv);
146 mutex_exit(&tq->tq_lock);
151 taskq_dispatch_delay(taskq_t *tq, task_func_t func, void *arg, uint_t tqflags,
158 taskq_empty_ent(taskq_ent_t *t)
160 return t->tqent_next == NULL;
164 taskq_init_ent(taskq_ent_t *t)
166 t->tqent_next = NULL;
167 t->tqent_prev = NULL;
168 t->tqent_func = NULL;
174 taskq_dispatch_ent(taskq_t *tq, task_func_t func, void *arg, uint_t flags,
177 ASSERT(func != NULL);
178 ASSERT(!(tq->tq_flags & TASKQ_DYNAMIC));
181 * Mark it as a prealloc'd task. This is important
182 * to ensure that we don't free it later.
184 t->tqent_flags |= TQENT_FLAG_PREALLOC;
186 * Enqueue the task to the underlying queue.
188 mutex_enter(&tq->tq_lock);
190 if (flags & TQ_FRONT) {
191 t->tqent_next = tq->tq_task.tqent_next;
192 t->tqent_prev = &tq->tq_task;
194 t->tqent_next = &tq->tq_task;
195 t->tqent_prev = tq->tq_task.tqent_prev;
197 t->tqent_next->tqent_prev = t;
198 t->tqent_prev->tqent_next = t;
199 t->tqent_func = func;
201 cv_signal(&tq->tq_dispatch_cv);
202 mutex_exit(&tq->tq_lock);
206 taskq_wait(taskq_t *tq)
208 mutex_enter(&tq->tq_lock);
209 while (tq->tq_task.tqent_next != &tq->tq_task || tq->tq_active != 0)
210 cv_wait(&tq->tq_wait_cv, &tq->tq_lock);
211 mutex_exit(&tq->tq_lock);
215 taskq_thread(void *arg)
221 mutex_enter(&tq->tq_lock);
222 while (tq->tq_flags & TASKQ_ACTIVE) {
223 if ((t = tq->tq_task.tqent_next) == &tq->tq_task) {
224 if (--tq->tq_active == 0)
225 cv_broadcast(&tq->tq_wait_cv);
226 cv_wait(&tq->tq_dispatch_cv, &tq->tq_lock);
230 t->tqent_prev->tqent_next = t->tqent_next;
231 t->tqent_next->tqent_prev = t->tqent_prev;
232 t->tqent_next = NULL;
233 t->tqent_prev = NULL;
234 prealloc = t->tqent_flags & TQENT_FLAG_PREALLOC;
235 mutex_exit(&tq->tq_lock);
237 rw_enter(&tq->tq_threadlock, RW_READER);
238 t->tqent_func(t->tqent_arg);
239 rw_exit(&tq->tq_threadlock);
241 mutex_enter(&tq->tq_lock);
246 cv_broadcast(&tq->tq_wait_cv);
247 mutex_exit(&tq->tq_lock);
253 taskq_create(const char *name, int nthreads, pri_t pri,
254 int minalloc, int maxalloc, uint_t flags)
256 taskq_t *tq = kmem_zalloc(sizeof (taskq_t), KM_SLEEP);
259 if (flags & TASKQ_THREADS_CPU_PCT) {
261 ASSERT3S(nthreads, >=, 0);
262 ASSERT3S(nthreads, <=, 100);
263 pct = MIN(nthreads, 100);
266 nthreads = (sysconf(_SC_NPROCESSORS_ONLN) * pct) / 100;
267 nthreads = MAX(nthreads, 1); /* need at least 1 thread */
269 ASSERT3S(nthreads, >=, 1);
272 rw_init(&tq->tq_threadlock, NULL, RW_DEFAULT, NULL);
273 mutex_init(&tq->tq_lock, NULL, MUTEX_DEFAULT, NULL);
274 cv_init(&tq->tq_dispatch_cv, NULL, CV_DEFAULT, NULL);
275 cv_init(&tq->tq_wait_cv, NULL, CV_DEFAULT, NULL);
276 cv_init(&tq->tq_maxalloc_cv, NULL, CV_DEFAULT, NULL);
277 tq->tq_flags = flags | TASKQ_ACTIVE;
278 tq->tq_active = nthreads;
279 tq->tq_nthreads = nthreads;
280 tq->tq_minalloc = minalloc;
281 tq->tq_maxalloc = maxalloc;
282 tq->tq_task.tqent_next = &tq->tq_task;
283 tq->tq_task.tqent_prev = &tq->tq_task;
284 tq->tq_threadlist = kmem_alloc(nthreads*sizeof(kthread_t *), KM_SLEEP);
286 if (flags & TASKQ_PREPOPULATE) {
287 mutex_enter(&tq->tq_lock);
288 while (minalloc-- > 0)
289 task_free(tq, task_alloc(tq, KM_SLEEP));
290 mutex_exit(&tq->tq_lock);
293 for (t = 0; t < nthreads; t++)
294 VERIFY((tq->tq_threadlist[t] = thread_create(NULL, 0,
295 taskq_thread, tq, TS_RUN, NULL, 0, 0)) != NULL);
301 taskq_destroy(taskq_t *tq)
303 int nthreads = tq->tq_nthreads;
307 mutex_enter(&tq->tq_lock);
309 tq->tq_flags &= ~TASKQ_ACTIVE;
310 cv_broadcast(&tq->tq_dispatch_cv);
312 while (tq->tq_nthreads != 0)
313 cv_wait(&tq->tq_wait_cv, &tq->tq_lock);
316 while (tq->tq_nalloc != 0) {
317 ASSERT(tq->tq_freelist != NULL);
318 task_free(tq, task_alloc(tq, KM_SLEEP));
321 mutex_exit(&tq->tq_lock);
323 kmem_free(tq->tq_threadlist, nthreads * sizeof (kthread_t *));
325 rw_destroy(&tq->tq_threadlock);
326 mutex_destroy(&tq->tq_lock);
327 cv_destroy(&tq->tq_dispatch_cv);
328 cv_destroy(&tq->tq_wait_cv);
329 cv_destroy(&tq->tq_maxalloc_cv);
331 kmem_free(tq, sizeof (taskq_t));
335 taskq_member(taskq_t *tq, kthread_t *t)
342 for (i = 0; i < tq->tq_nthreads; i++)
343 if (tq->tq_threadlist[i] == t)
350 taskq_cancel_id(taskq_t *tq, taskqid_t id)
356 system_taskq_init(void)
358 system_taskq = taskq_create("system_taskq", 64, minclsyspri, 4, 512,
359 TASKQ_DYNAMIC | TASKQ_PREPOPULATE);
363 system_taskq_fini(void)
365 taskq_destroy(system_taskq);
366 system_taskq = NULL; /* defensive */