taskq.c revision 208047
1168404Spjd/* 2168404Spjd * CDDL HEADER START 3168404Spjd * 4168404Spjd * The contents of this file are subject to the terms of the 5185029Spjd * Common Development and Distribution License (the "License"). 6185029Spjd * You may not use this file except in compliance with the License. 7168404Spjd * 8168404Spjd * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9168404Spjd * or http://www.opensolaris.org/os/licensing. 10168404Spjd * See the License for the specific language governing permissions 11168404Spjd * and limitations under the License. 12168404Spjd * 13168404Spjd * When distributing Covered Code, include this CDDL HEADER in each 14168404Spjd * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15168404Spjd * If applicable, add the following below this CDDL HEADER, with the 16168404Spjd * fields enclosed by brackets "[]" replaced with your own identifying 17168404Spjd * information: Portions Copyright [yyyy] [name of copyright owner] 18168404Spjd * 19168404Spjd * CDDL HEADER END 20168404Spjd */ 21168404Spjd/* 22208047Smm * Copyright 2008 Sun Microsystems, Inc. All rights reserved. 23168404Spjd * Use is subject to license terms. 24168404Spjd */ 25168404Spjd 26168404Spjd#include <sys/zfs_context.h> 27168404Spjd 28168404Spjdint taskq_now; 29208047Smmtaskq_t *system_taskq; 30168404Spjd 31168404Spjdtypedef struct task { 32168404Spjd struct task *task_next; 33168404Spjd struct task *task_prev; 34168404Spjd task_func_t *task_func; 35168404Spjd void *task_arg; 36168404Spjd} task_t; 37168404Spjd 38168404Spjd#define TASKQ_ACTIVE 0x00010000 39168404Spjd 40168404Spjdstruct taskq { 41168404Spjd kmutex_t tq_lock; 42168404Spjd krwlock_t tq_threadlock; 43168404Spjd kcondvar_t tq_dispatch_cv; 44168404Spjd kcondvar_t tq_wait_cv; 45168404Spjd thread_t *tq_threadlist; 46168404Spjd int tq_flags; 47168404Spjd int tq_active; 48168404Spjd int tq_nthreads; 49168404Spjd int tq_nalloc; 50168404Spjd int tq_minalloc; 51168404Spjd int tq_maxalloc; 52168404Spjd task_t *tq_freelist; 53168404Spjd task_t tq_task; 54168404Spjd}; 55168404Spjd 56168404Spjdstatic task_t * 57168404Spjdtask_alloc(taskq_t *tq, int tqflags) 58168404Spjd{ 59168404Spjd task_t *t; 60168404Spjd 61168404Spjd if ((t = tq->tq_freelist) != NULL && tq->tq_nalloc >= tq->tq_minalloc) { 62168404Spjd tq->tq_freelist = t->task_next; 63168404Spjd } else { 64168404Spjd mutex_exit(&tq->tq_lock); 65168404Spjd if (tq->tq_nalloc >= tq->tq_maxalloc) { 66168404Spjd if (!(tqflags & KM_SLEEP)) { 67168404Spjd mutex_enter(&tq->tq_lock); 68168404Spjd return (NULL); 69168404Spjd } 70168404Spjd /* 71168404Spjd * We don't want to exceed tq_maxalloc, but we can't 72168404Spjd * wait for other tasks to complete (and thus free up 73168404Spjd * task structures) without risking deadlock with 74168404Spjd * the caller. So, we just delay for one second 75168404Spjd * to throttle the allocation rate. 76168404Spjd */ 77168404Spjd delay(hz); 78168404Spjd } 79168404Spjd t = kmem_alloc(sizeof (task_t), tqflags); 80168404Spjd mutex_enter(&tq->tq_lock); 81168404Spjd if (t != NULL) 82168404Spjd tq->tq_nalloc++; 83168404Spjd } 84168404Spjd return (t); 85168404Spjd} 86168404Spjd 87168404Spjdstatic void 88168404Spjdtask_free(taskq_t *tq, task_t *t) 89168404Spjd{ 90168404Spjd if (tq->tq_nalloc <= tq->tq_minalloc) { 91168404Spjd t->task_next = tq->tq_freelist; 92168404Spjd tq->tq_freelist = t; 93168404Spjd } else { 94168404Spjd tq->tq_nalloc--; 95168404Spjd mutex_exit(&tq->tq_lock); 96168404Spjd kmem_free(t, sizeof (task_t)); 97168404Spjd mutex_enter(&tq->tq_lock); 98168404Spjd } 99168404Spjd} 100168404Spjd 101168404Spjdtaskqid_t 102168404Spjdtaskq_dispatch(taskq_t *tq, task_func_t func, void *arg, uint_t tqflags) 103168404Spjd{ 104168404Spjd task_t *t; 105168404Spjd 106168404Spjd if (taskq_now) { 107168404Spjd func(arg); 108168404Spjd return (1); 109168404Spjd } 110168404Spjd 111168404Spjd mutex_enter(&tq->tq_lock); 112168404Spjd ASSERT(tq->tq_flags & TASKQ_ACTIVE); 113168404Spjd if ((t = task_alloc(tq, tqflags)) == NULL) { 114168404Spjd mutex_exit(&tq->tq_lock); 115168404Spjd return (0); 116168404Spjd } 117168404Spjd t->task_next = &tq->tq_task; 118168404Spjd t->task_prev = tq->tq_task.task_prev; 119168404Spjd t->task_next->task_prev = t; 120168404Spjd t->task_prev->task_next = t; 121168404Spjd t->task_func = func; 122168404Spjd t->task_arg = arg; 123168404Spjd cv_signal(&tq->tq_dispatch_cv); 124168404Spjd mutex_exit(&tq->tq_lock); 125168404Spjd return (1); 126168404Spjd} 127168404Spjd 128168404Spjdvoid 129168404Spjdtaskq_wait(taskq_t *tq) 130168404Spjd{ 131168404Spjd mutex_enter(&tq->tq_lock); 132168404Spjd while (tq->tq_task.task_next != &tq->tq_task || tq->tq_active != 0) 133168404Spjd cv_wait(&tq->tq_wait_cv, &tq->tq_lock); 134168404Spjd mutex_exit(&tq->tq_lock); 135168404Spjd} 136168404Spjd 137168404Spjdstatic void * 138168404Spjdtaskq_thread(void *arg) 139168404Spjd{ 140168404Spjd taskq_t *tq = arg; 141168404Spjd task_t *t; 142168404Spjd 143168404Spjd mutex_enter(&tq->tq_lock); 144168404Spjd while (tq->tq_flags & TASKQ_ACTIVE) { 145168404Spjd if ((t = tq->tq_task.task_next) == &tq->tq_task) { 146168404Spjd if (--tq->tq_active == 0) 147168404Spjd cv_broadcast(&tq->tq_wait_cv); 148168404Spjd cv_wait(&tq->tq_dispatch_cv, &tq->tq_lock); 149168404Spjd tq->tq_active++; 150168404Spjd continue; 151168404Spjd } 152168404Spjd t->task_prev->task_next = t->task_next; 153168404Spjd t->task_next->task_prev = t->task_prev; 154168404Spjd mutex_exit(&tq->tq_lock); 155168404Spjd 156168404Spjd rw_enter(&tq->tq_threadlock, RW_READER); 157168404Spjd t->task_func(t->task_arg); 158168404Spjd rw_exit(&tq->tq_threadlock); 159168404Spjd 160168404Spjd mutex_enter(&tq->tq_lock); 161168404Spjd task_free(tq, t); 162168404Spjd } 163168404Spjd tq->tq_nthreads--; 164168404Spjd cv_broadcast(&tq->tq_wait_cv); 165168404Spjd mutex_exit(&tq->tq_lock); 166168404Spjd return (NULL); 167168404Spjd} 168168404Spjd 169168404Spjd/*ARGSUSED*/ 170168404Spjdtaskq_t * 171168404Spjdtaskq_create(const char *name, int nthreads, pri_t pri, 172168404Spjd int minalloc, int maxalloc, uint_t flags) 173168404Spjd{ 174168404Spjd taskq_t *tq = kmem_zalloc(sizeof (taskq_t), KM_SLEEP); 175168404Spjd int t; 176168404Spjd 177168404Spjd rw_init(&tq->tq_threadlock, NULL, RW_DEFAULT, NULL); 178185029Spjd mutex_init(&tq->tq_lock, NULL, MUTEX_DEFAULT, NULL); 179185029Spjd cv_init(&tq->tq_dispatch_cv, NULL, CV_DEFAULT, NULL); 180185029Spjd cv_init(&tq->tq_wait_cv, NULL, CV_DEFAULT, NULL); 181168404Spjd tq->tq_flags = flags | TASKQ_ACTIVE; 182168404Spjd tq->tq_active = nthreads; 183168404Spjd tq->tq_nthreads = nthreads; 184168404Spjd tq->tq_minalloc = minalloc; 185168404Spjd tq->tq_maxalloc = maxalloc; 186168404Spjd tq->tq_task.task_next = &tq->tq_task; 187168404Spjd tq->tq_task.task_prev = &tq->tq_task; 188168404Spjd tq->tq_threadlist = kmem_alloc(nthreads * sizeof (thread_t), KM_SLEEP); 189168404Spjd 190168404Spjd if (flags & TASKQ_PREPOPULATE) { 191168404Spjd mutex_enter(&tq->tq_lock); 192168404Spjd while (minalloc-- > 0) 193168404Spjd task_free(tq, task_alloc(tq, KM_SLEEP)); 194168404Spjd mutex_exit(&tq->tq_lock); 195168404Spjd } 196168404Spjd 197168404Spjd for (t = 0; t < nthreads; t++) 198168404Spjd (void) thr_create(0, 0, taskq_thread, 199168404Spjd tq, THR_BOUND, &tq->tq_threadlist[t]); 200168404Spjd 201168404Spjd return (tq); 202168404Spjd} 203168404Spjd 204168404Spjdvoid 205168404Spjdtaskq_destroy(taskq_t *tq) 206168404Spjd{ 207168404Spjd int t; 208168404Spjd int nthreads = tq->tq_nthreads; 209168404Spjd 210168404Spjd taskq_wait(tq); 211168404Spjd 212168404Spjd mutex_enter(&tq->tq_lock); 213168404Spjd 214168404Spjd tq->tq_flags &= ~TASKQ_ACTIVE; 215168404Spjd cv_broadcast(&tq->tq_dispatch_cv); 216168404Spjd 217168404Spjd while (tq->tq_nthreads != 0) 218168404Spjd cv_wait(&tq->tq_wait_cv, &tq->tq_lock); 219168404Spjd 220168404Spjd tq->tq_minalloc = 0; 221168404Spjd while (tq->tq_nalloc != 0) { 222168404Spjd ASSERT(tq->tq_freelist != NULL); 223168404Spjd task_free(tq, task_alloc(tq, KM_SLEEP)); 224168404Spjd } 225168404Spjd 226168404Spjd mutex_exit(&tq->tq_lock); 227168404Spjd 228168404Spjd for (t = 0; t < nthreads; t++) 229168404Spjd (void) thr_join(tq->tq_threadlist[t], NULL, NULL); 230168404Spjd 231168404Spjd kmem_free(tq->tq_threadlist, nthreads * sizeof (thread_t)); 232168404Spjd 233168404Spjd rw_destroy(&tq->tq_threadlock); 234185029Spjd mutex_destroy(&tq->tq_lock); 235185029Spjd cv_destroy(&tq->tq_dispatch_cv); 236185029Spjd cv_destroy(&tq->tq_wait_cv); 237168404Spjd 238168404Spjd kmem_free(tq, sizeof (taskq_t)); 239168404Spjd} 240168404Spjd 241168404Spjdint 242168404Spjdtaskq_member(taskq_t *tq, void *t) 243168404Spjd{ 244168404Spjd int i; 245168404Spjd 246168404Spjd if (taskq_now) 247168404Spjd return (1); 248168404Spjd 249168404Spjd for (i = 0; i < tq->tq_nthreads; i++) 250168404Spjd if (tq->tq_threadlist[i] == (thread_t)(uintptr_t)t) 251168404Spjd return (1); 252168404Spjd 253168404Spjd return (0); 254168404Spjd} 255208047Smm 256208047Smmvoid 257208047Smmsystem_taskq_init(void) 258208047Smm{ 259208047Smm system_taskq = taskq_create("system_taskq", 64, minclsyspri, 4, 512, 260208047Smm TASKQ_DYNAMIC | TASKQ_PREPOPULATE); 261208047Smm} 262