1 /* 2 * CDDL HEADER START 3 * 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. 7 * 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. 12 * 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] 18 * 19 * CDDL HEADER END 20 */ 21 /* 22 * Copyright 2009 Sun Microsystems, Inc. All rights reserved. 23 * Use is subject to license terms. 24 */ 25 26 #include <sys/zfs_context.h> 27 28 int taskq_now; 29 taskq_t *system_taskq; 30 31 typedef struct task { 32 struct task *task_next; 33 struct task *task_prev; 34 task_func_t *task_func; 35 void *task_arg; 36 } task_t; 37 38 #define TASKQ_ACTIVE 0x00010000 39 40 struct taskq { 41 kmutex_t tq_lock; 42 krwlock_t tq_threadlock; 43 kcondvar_t tq_dispatch_cv; 44 kcondvar_t tq_wait_cv; 45 thread_t *tq_threadlist; 46 int tq_flags; 47 int tq_active; 48 int tq_nthreads; 49 int tq_nalloc; 50 int tq_minalloc; 51 int tq_maxalloc; 52 task_t *tq_freelist; 53 task_t tq_task; 54 }; 55 56 static task_t * 57 task_alloc(taskq_t *tq, int tqflags) 58 { 59 task_t *t; 60 61 if ((t = tq->tq_freelist) != NULL && tq->tq_nalloc >= tq->tq_minalloc) { 62 tq->tq_freelist = t->task_next; 63 } else { 64 mutex_exit(&tq->tq_lock); 65 if (tq->tq_nalloc >= tq->tq_maxalloc) { 66 if (!(tqflags & KM_SLEEP)) { 67 mutex_enter(&tq->tq_lock); 68 return (NULL); 69 } 70 /* 71 * We don't want to exceed tq_maxalloc, but we can't 72 * wait for other tasks to complete (and thus free up 73 * task structures) without risking deadlock with 74 * the caller. So, we just delay for one second 75 * to throttle the allocation rate. 76 */ 77 delay(hz); 78 } 79 80 /* Clean up TQ_FRONT from tqflags before passing it to kmem */ 81 t = kmem_alloc(sizeof (task_t), 82 tqflags & (KM_SLEEP | KM_NOSLEEP)); 83 mutex_enter(&tq->tq_lock); 84 if (t != NULL) 85 tq->tq_nalloc++; 86 } 87 return (t); 88 } 89 90 static void 91 task_free(taskq_t *tq, task_t *t) 92 { 93 if (tq->tq_nalloc <= tq->tq_minalloc) { 94 t->task_next = tq->tq_freelist; 95 tq->tq_freelist = t; 96 } else { 97 tq->tq_nalloc--; 98 mutex_exit(&tq->tq_lock); 99 kmem_free(t, sizeof (task_t)); 100 mutex_enter(&tq->tq_lock); 101 } 102 } 103 104 taskqid_t 105 taskq_dispatch(taskq_t *tq, task_func_t func, void *arg, uint_t tqflags) 106 { 107 task_t *t; 108 109 if (taskq_now) { 110 func(arg); 111 return (1); 112 } 113 114 mutex_enter(&tq->tq_lock); 115 ASSERT(tq->tq_flags & TASKQ_ACTIVE); 116 if ((t = task_alloc(tq, tqflags)) == NULL) { 117 mutex_exit(&tq->tq_lock); 118 return (0); 119 } 120 if (tqflags & TQ_FRONT) { 121 t->task_next = tq->tq_task.task_next; 122 t->task_prev = &tq->tq_task; 123 } else { 124 t->task_next = &tq->tq_task; 125 t->task_prev = tq->tq_task.task_prev; 126 } 127 t->task_next->task_prev = t; 128 t->task_prev->task_next = t; 129 t->task_func = func; 130 t->task_arg = arg; 131 cv_signal(&tq->tq_dispatch_cv); 132 mutex_exit(&tq->tq_lock); 133 return (1); 134 } 135 136 void 137 taskq_wait(taskq_t *tq) 138 { 139 mutex_enter(&tq->tq_lock); 140 while (tq->tq_task.task_next != &tq->tq_task || tq->tq_active != 0) 141 cv_wait(&tq->tq_wait_cv, &tq->tq_lock); 142 mutex_exit(&tq->tq_lock); 143 } 144 145 static void * 146 taskq_thread(void *arg) 147 { 148 taskq_t *tq = arg; 149 task_t *t; 150 151 mutex_enter(&tq->tq_lock); 152 while (tq->tq_flags & TASKQ_ACTIVE) { 153 if ((t = tq->tq_task.task_next) == &tq->tq_task) { 154 if (--tq->tq_active == 0) 155 cv_broadcast(&tq->tq_wait_cv); 156 cv_wait(&tq->tq_dispatch_cv, &tq->tq_lock); 157 tq->tq_active++; 158 continue; 159 } 160 t->task_prev->task_next = t->task_next; 161 t->task_next->task_prev = t->task_prev; 162 mutex_exit(&tq->tq_lock); 163 164 rw_enter(&tq->tq_threadlock, RW_READER); 165 t->task_func(t->task_arg); 166 rw_exit(&tq->tq_threadlock); 167 168 mutex_enter(&tq->tq_lock); 169 task_free(tq, t); 170 } 171 tq->tq_nthreads--; 172 cv_broadcast(&tq->tq_wait_cv); 173 mutex_exit(&tq->tq_lock); 174 return (NULL); 175 } 176 177 /*ARGSUSED*/ 178 taskq_t * 179 taskq_create(const char *name, int nthreads, pri_t pri, 180 int minalloc, int maxalloc, uint_t flags) 181 { 182 taskq_t *tq = kmem_zalloc(sizeof (taskq_t), KM_SLEEP); 183 int t; 184 185 if (flags & TASKQ_THREADS_CPU_PCT) { 186 int pct; 187 ASSERT3S(nthreads, >=, 0); 188 ASSERT3S(nthreads, <=, 100); 189 pct = MIN(nthreads, 100); 190 pct = MAX(pct, 0); 191 192 nthreads = (sysconf(_SC_NPROCESSORS_ONLN) * pct) / 100; 193 nthreads = MAX(nthreads, 1); /* need at least 1 thread */ 194 } else { 195 ASSERT3S(nthreads, >=, 1); 196 } 197 198 rw_init(&tq->tq_threadlock, NULL, RW_DEFAULT, NULL); 199 mutex_init(&tq->tq_lock, NULL, MUTEX_DEFAULT, NULL); 200 cv_init(&tq->tq_dispatch_cv, NULL, CV_DEFAULT, NULL); 201 cv_init(&tq->tq_wait_cv, NULL, CV_DEFAULT, NULL); 202 tq->tq_flags = flags | TASKQ_ACTIVE; 203 tq->tq_active = nthreads; 204 tq->tq_nthreads = nthreads; 205 tq->tq_minalloc = minalloc; 206 tq->tq_maxalloc = maxalloc; 207 tq->tq_task.task_next = &tq->tq_task; 208 tq->tq_task.task_prev = &tq->tq_task; 209 tq->tq_threadlist = kmem_alloc(nthreads * sizeof (thread_t), KM_SLEEP); 210 211 if (flags & TASKQ_PREPOPULATE) { 212 mutex_enter(&tq->tq_lock); 213 while (minalloc-- > 0) 214 task_free(tq, task_alloc(tq, KM_SLEEP)); 215 mutex_exit(&tq->tq_lock); 216 } 217 218 for (t = 0; t < nthreads; t++) 219 (void) thr_create(0, 0, taskq_thread, 220 tq, THR_BOUND, &tq->tq_threadlist[t]); 221 222 return (tq); 223 } 224 225 void 226 taskq_destroy(taskq_t *tq) 227 { 228 int t; 229 int nthreads = tq->tq_nthreads; 230 231 taskq_wait(tq); 232 233 mutex_enter(&tq->tq_lock); 234 235 tq->tq_flags &= ~TASKQ_ACTIVE; 236 cv_broadcast(&tq->tq_dispatch_cv); 237 238 while (tq->tq_nthreads != 0) 239 cv_wait(&tq->tq_wait_cv, &tq->tq_lock); 240 241 tq->tq_minalloc = 0; 242 while (tq->tq_nalloc != 0) { 243 ASSERT(tq->tq_freelist != NULL); 244 task_free(tq, task_alloc(tq, KM_SLEEP)); 245 } 246 247 mutex_exit(&tq->tq_lock); 248 249 for (t = 0; t < nthreads; t++) 250 (void) thr_join(tq->tq_threadlist[t], NULL, NULL); 251 252 kmem_free(tq->tq_threadlist, nthreads * sizeof (thread_t)); 253 254 rw_destroy(&tq->tq_threadlock); 255 mutex_destroy(&tq->tq_lock); 256 cv_destroy(&tq->tq_dispatch_cv); 257 cv_destroy(&tq->tq_wait_cv); 258 259 kmem_free(tq, sizeof (taskq_t)); 260 } 261 262 int 263 taskq_member(taskq_t *tq, void *t) 264 { 265 int i; 266 267 if (taskq_now) 268 return (1); 269 270 for (i = 0; i < tq->tq_nthreads; i++) 271 if (tq->tq_threadlist[i] == (thread_t)(uintptr_t)t) 272 return (1); 273 274 return (0); 275 } 276 277 void 278 system_taskq_init(void) 279 { 280 system_taskq = taskq_create("system_taskq", 64, minclsyspri, 4, 512, 281 TASKQ_DYNAMIC | TASKQ_PREPOPULATE); 282 } 283 284 void 285 system_taskq_fini(void) 286 { 287 taskq_destroy(system_taskq); 288 system_taskq = NULL; /* defensive */ 289 } 290