diff options
Diffstat (limited to 'cddl/contrib/opensolaris/lib/libzpool/common/taskq.c')
| -rw-r--r-- | cddl/contrib/opensolaris/lib/libzpool/common/taskq.c | 250 |
1 files changed, 250 insertions, 0 deletions
diff --git a/cddl/contrib/opensolaris/lib/libzpool/common/taskq.c b/cddl/contrib/opensolaris/lib/libzpool/common/taskq.c new file mode 100644 index 0000000..f7b6571 --- /dev/null +++ b/cddl/contrib/opensolaris/lib/libzpool/common/taskq.c @@ -0,0 +1,250 @@ +/* + * CDDL HEADER START + * + * The contents of this file are subject to the terms of the + * Common Development and Distribution License, Version 1.0 only + * (the "License"). You may not use this file except in compliance + * with the License. + * + * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE + * or http://www.opensolaris.org/os/licensing. + * See the License for the specific language governing permissions + * and limitations under the License. + * + * When distributing Covered Code, include this CDDL HEADER in each + * file and include the License file at usr/src/OPENSOLARIS.LICENSE. + * If applicable, add the following below this CDDL HEADER, with the + * fields enclosed by brackets "[]" replaced with your own identifying + * information: Portions Copyright [yyyy] [name of copyright owner] + * + * CDDL HEADER END + */ +/* + * Copyright 2005 Sun Microsystems, Inc. All rights reserved. + * Use is subject to license terms. + */ + +#pragma ident "%Z%%M% %I% %E% SMI" + +#include <sys/zfs_context.h> + +int taskq_now; + +typedef struct task { + struct task *task_next; + struct task *task_prev; + task_func_t *task_func; + void *task_arg; +} task_t; + +#define TASKQ_ACTIVE 0x00010000 + +struct taskq { + kmutex_t tq_lock; + krwlock_t tq_threadlock; + kcondvar_t tq_dispatch_cv; + kcondvar_t tq_wait_cv; + thread_t *tq_threadlist; + int tq_flags; + int tq_active; + int tq_nthreads; + int tq_nalloc; + int tq_minalloc; + int tq_maxalloc; + task_t *tq_freelist; + task_t tq_task; +}; + +static task_t * +task_alloc(taskq_t *tq, int tqflags) +{ + task_t *t; + + if ((t = tq->tq_freelist) != NULL && tq->tq_nalloc >= tq->tq_minalloc) { + tq->tq_freelist = t->task_next; + } else { + mutex_exit(&tq->tq_lock); + if (tq->tq_nalloc >= tq->tq_maxalloc) { + if (!(tqflags & KM_SLEEP)) { + mutex_enter(&tq->tq_lock); + return (NULL); + } + /* + * We don't want to exceed tq_maxalloc, but we can't + * wait for other tasks to complete (and thus free up + * task structures) without risking deadlock with + * the caller. So, we just delay for one second + * to throttle the allocation rate. + */ + delay(hz); + } + t = kmem_alloc(sizeof (task_t), tqflags); + mutex_enter(&tq->tq_lock); + if (t != NULL) + tq->tq_nalloc++; + } + return (t); +} + +static void +task_free(taskq_t *tq, task_t *t) +{ + if (tq->tq_nalloc <= tq->tq_minalloc) { + t->task_next = tq->tq_freelist; + tq->tq_freelist = t; + } else { + tq->tq_nalloc--; + mutex_exit(&tq->tq_lock); + kmem_free(t, sizeof (task_t)); + mutex_enter(&tq->tq_lock); + } +} + +taskqid_t +taskq_dispatch(taskq_t *tq, task_func_t func, void *arg, uint_t tqflags) +{ + task_t *t; + + if (taskq_now) { + func(arg); + return (1); + } + + mutex_enter(&tq->tq_lock); + ASSERT(tq->tq_flags & TASKQ_ACTIVE); + if ((t = task_alloc(tq, tqflags)) == NULL) { + mutex_exit(&tq->tq_lock); + return (0); + } + t->task_next = &tq->tq_task; + t->task_prev = tq->tq_task.task_prev; + t->task_next->task_prev = t; + t->task_prev->task_next = t; + t->task_func = func; + t->task_arg = arg; + cv_signal(&tq->tq_dispatch_cv); + mutex_exit(&tq->tq_lock); + return (1); +} + +void +taskq_wait(taskq_t *tq) +{ + mutex_enter(&tq->tq_lock); + while (tq->tq_task.task_next != &tq->tq_task || tq->tq_active != 0) + cv_wait(&tq->tq_wait_cv, &tq->tq_lock); + mutex_exit(&tq->tq_lock); +} + +static void * +taskq_thread(void *arg) +{ + taskq_t *tq = arg; + task_t *t; + + mutex_enter(&tq->tq_lock); + while (tq->tq_flags & TASKQ_ACTIVE) { + if ((t = tq->tq_task.task_next) == &tq->tq_task) { + if (--tq->tq_active == 0) + cv_broadcast(&tq->tq_wait_cv); + cv_wait(&tq->tq_dispatch_cv, &tq->tq_lock); + tq->tq_active++; + continue; + } + t->task_prev->task_next = t->task_next; + t->task_next->task_prev = t->task_prev; + mutex_exit(&tq->tq_lock); + + rw_enter(&tq->tq_threadlock, RW_READER); + t->task_func(t->task_arg); + rw_exit(&tq->tq_threadlock); + + mutex_enter(&tq->tq_lock); + task_free(tq, t); + } + tq->tq_nthreads--; + cv_broadcast(&tq->tq_wait_cv); + mutex_exit(&tq->tq_lock); + return (NULL); +} + +/*ARGSUSED*/ +taskq_t * +taskq_create(const char *name, int nthreads, pri_t pri, + int minalloc, int maxalloc, uint_t flags) +{ + taskq_t *tq = kmem_zalloc(sizeof (taskq_t), KM_SLEEP); + int t; + + rw_init(&tq->tq_threadlock, NULL, RW_DEFAULT, NULL); + tq->tq_flags = flags | TASKQ_ACTIVE; + tq->tq_active = nthreads; + tq->tq_nthreads = nthreads; + tq->tq_minalloc = minalloc; + tq->tq_maxalloc = maxalloc; + tq->tq_task.task_next = &tq->tq_task; + tq->tq_task.task_prev = &tq->tq_task; + tq->tq_threadlist = kmem_alloc(nthreads * sizeof (thread_t), KM_SLEEP); + + if (flags & TASKQ_PREPOPULATE) { + mutex_enter(&tq->tq_lock); + while (minalloc-- > 0) + task_free(tq, task_alloc(tq, KM_SLEEP)); + mutex_exit(&tq->tq_lock); + } + + for (t = 0; t < nthreads; t++) + (void) thr_create(0, 0, taskq_thread, + tq, THR_BOUND, &tq->tq_threadlist[t]); + + return (tq); +} + +void +taskq_destroy(taskq_t *tq) +{ + int t; + int nthreads = tq->tq_nthreads; + + taskq_wait(tq); + + mutex_enter(&tq->tq_lock); + + tq->tq_flags &= ~TASKQ_ACTIVE; + cv_broadcast(&tq->tq_dispatch_cv); + + while (tq->tq_nthreads != 0) + cv_wait(&tq->tq_wait_cv, &tq->tq_lock); + + tq->tq_minalloc = 0; + while (tq->tq_nalloc != 0) { + ASSERT(tq->tq_freelist != NULL); + task_free(tq, task_alloc(tq, KM_SLEEP)); + } + + mutex_exit(&tq->tq_lock); + + for (t = 0; t < nthreads; t++) + (void) thr_join(tq->tq_threadlist[t], NULL, NULL); + + kmem_free(tq->tq_threadlist, nthreads * sizeof (thread_t)); + + rw_destroy(&tq->tq_threadlock); + + kmem_free(tq, sizeof (taskq_t)); +} + +int +taskq_member(taskq_t *tq, void *t) +{ + int i; + + if (taskq_now) + return (1); + + for (i = 0; i < tq->tq_nthreads; i++) + if (tq->tq_threadlist[i] == (thread_t)(uintptr_t)t) + return (1); + + return (0); +} |
