diff options
Diffstat (limited to 'lib/libzpool/taskq.c')
| -rw-r--r-- | lib/libzpool/taskq.c | 49 |
1 files changed, 39 insertions, 10 deletions
diff --git a/lib/libzpool/taskq.c b/lib/libzpool/taskq.c index 1a73fe83c..8db5d11c1 100644 --- a/lib/libzpool/taskq.c +++ b/lib/libzpool/taskq.c @@ -19,7 +19,7 @@ * CDDL HEADER END */ /* - * Copyright 2009 Sun Microsystems, Inc. All rights reserved. + * Copyright 2010 Sun Microsystems, Inc. All rights reserved. * Use is subject to license terms. */ @@ -49,6 +49,8 @@ struct taskq { int tq_nalloc; int tq_minalloc; int tq_maxalloc; + kcondvar_t tq_maxalloc_cv; + int tq_maxalloc_wait; task_t *tq_freelist; task_t tq_task; }; @@ -57,26 +59,36 @@ static task_t * task_alloc(taskq_t *tq, int tqflags) { task_t *t; + int rv; - if ((t = tq->tq_freelist) != NULL && tq->tq_nalloc >= tq->tq_minalloc) { +again: 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); + if (!(tqflags & KM_SLEEP)) 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. + * to throttle the allocation rate. If we have tasks + * complete before one second timeout expires then + * taskq_ent_free will signal us and we will + * immediately retry the allocation. */ - delay(hz); + tq->tq_maxalloc_wait++; + rv = cv_timedwait(&tq->tq_maxalloc_cv, + &tq->tq_lock, ddi_get_lbolt() + hz); + tq->tq_maxalloc_wait--; + if (rv > 0) + goto again; /* signaled */ } + mutex_exit(&tq->tq_lock); + t = kmem_alloc(sizeof (task_t), tqflags); + mutex_enter(&tq->tq_lock); if (t != NULL) tq->tq_nalloc++; @@ -96,6 +108,9 @@ task_free(taskq_t *tq, task_t *t) kmem_free(t, sizeof (task_t)); mutex_enter(&tq->tq_lock); } + + if (tq->tq_maxalloc_wait) + cv_signal(&tq->tq_maxalloc_cv); } taskqid_t @@ -114,8 +129,13 @@ taskq_dispatch(taskq_t *tq, task_func_t func, void *arg, uint_t tqflags) mutex_exit(&tq->tq_lock); return (0); } - t->task_next = &tq->tq_task; - t->task_prev = tq->tq_task.task_prev; + if (tqflags & TQ_FRONT) { + t->task_next = tq->tq_task.task_next; + t->task_prev = &tq->tq_task; + } else { + 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; @@ -191,6 +211,7 @@ taskq_create(const char *name, int nthreads, pri_t pri, mutex_init(&tq->tq_lock, NULL, MUTEX_DEFAULT, NULL); cv_init(&tq->tq_dispatch_cv, NULL, CV_DEFAULT, NULL); cv_init(&tq->tq_wait_cv, NULL, CV_DEFAULT, NULL); + cv_init(&tq->tq_maxalloc_cv, NULL, CV_DEFAULT, NULL); tq->tq_flags = flags | TASKQ_ACTIVE; tq->tq_active = nthreads; tq->tq_nthreads = nthreads; @@ -247,6 +268,7 @@ taskq_destroy(taskq_t *tq) mutex_destroy(&tq->tq_lock); cv_destroy(&tq->tq_dispatch_cv); cv_destroy(&tq->tq_wait_cv); + cv_destroy(&tq->tq_maxalloc_cv); kmem_free(tq, sizeof (taskq_t)); } @@ -272,3 +294,10 @@ system_taskq_init(void) system_taskq = taskq_create("system_taskq", 64, minclsyspri, 4, 512, TASKQ_DYNAMIC | TASKQ_PREPOPULATE); } + +void +system_taskq_fini(void) +{ + taskq_destroy(system_taskq); + system_taskq = NULL; /* defensive */ +} |