1 /* $NetBSD: subr_workqueue.c,v 1.25 2008/07/02 14:47:34 matt Exp $ */ 2 3 /*- 4 * Copyright (c)2002, 2005, 2006, 2007 YAMAMOTO Takashi, 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 __KERNEL_RCSID(0, "$NetBSD: subr_workqueue.c,v 1.25 2008/07/02 14:47:34 matt Exp $"); 31 32 #include <sys/param.h> 33 #include <sys/cpu.h> 34 #include <sys/systm.h> 35 #include <sys/kthread.h> 36 #include <sys/kmem.h> 37 #include <sys/proc.h> 38 #include <sys/workqueue.h> 39 #include <sys/mutex.h> 40 #include <sys/condvar.h> 41 #include <sys/queue.h> 42 43 typedef struct work_impl { 44 SIMPLEQ_ENTRY(work_impl) wk_entry; 45 } work_impl_t; 46 47 SIMPLEQ_HEAD(workqhead, work_impl); 48 49 struct workqueue_queue { 50 kmutex_t q_mutex; 51 kcondvar_t q_cv; 52 struct workqhead q_queue; 53 struct lwp *q_worker; 54 }; 55 56 struct workqueue { 57 void (*wq_func)(struct work *, void *); 58 void *wq_arg; 59 int wq_flags; 60 61 const char *wq_name; 62 pri_t wq_prio; 63 void *wq_ptr; 64 }; 65 66 #define WQ_SIZE (roundup2(sizeof(struct workqueue), coherency_unit)) 67 #define WQ_QUEUE_SIZE (roundup2(sizeof(struct workqueue_queue), coherency_unit)) 68 69 #define POISON 0xaabbccdd 70 71 static size_t 72 workqueue_size(int flags) 73 { 74 75 return WQ_SIZE 76 + ((flags & WQ_PERCPU) != 0 ? ncpu : 1) * WQ_QUEUE_SIZE 77 + coherency_unit; 78 } 79 80 static struct workqueue_queue * 81 workqueue_queue_lookup(struct workqueue *wq, struct cpu_info *ci) 82 { 83 u_int idx = 0; 84 85 if (wq->wq_flags & WQ_PERCPU) { 86 idx = ci ? cpu_index(ci) : cpu_index(curcpu()); 87 } 88 89 return (void *)((intptr_t)(wq) + WQ_SIZE + (idx * WQ_QUEUE_SIZE)); 90 } 91 92 static void 93 workqueue_runlist(struct workqueue *wq, struct workqhead *list) 94 { 95 work_impl_t *wk; 96 work_impl_t *next; 97 98 /* 99 * note that "list" is not a complete SIMPLEQ. 100 */ 101 102 for (wk = SIMPLEQ_FIRST(list); wk != NULL; wk = next) { 103 next = SIMPLEQ_NEXT(wk, wk_entry); 104 (*wq->wq_func)((void *)wk, wq->wq_arg); 105 } 106 } 107 108 static void 109 workqueue_worker(void *cookie) 110 { 111 struct workqueue *wq = cookie; 112 struct workqueue_queue *q; 113 114 /* find the workqueue of this kthread */ 115 q = workqueue_queue_lookup(wq, curlwp->l_cpu); 116 117 for (;;) { 118 struct workqhead tmp; 119 120 /* 121 * we violate abstraction of SIMPLEQ. 122 */ 123 124 #if defined(DIAGNOSTIC) 125 tmp.sqh_last = (void *)POISON; 126 #endif /* defined(DIAGNOSTIC) */ 127 128 mutex_enter(&q->q_mutex); 129 while (SIMPLEQ_EMPTY(&q->q_queue)) 130 cv_wait(&q->q_cv, &q->q_mutex); 131 tmp.sqh_first = q->q_queue.sqh_first; /* XXX */ 132 SIMPLEQ_INIT(&q->q_queue); 133 mutex_exit(&q->q_mutex); 134 135 workqueue_runlist(wq, &tmp); 136 } 137 } 138 139 static void 140 workqueue_init(struct workqueue *wq, const char *name, 141 void (*callback_func)(struct work *, void *), void *callback_arg, 142 pri_t prio, int ipl) 143 { 144 145 wq->wq_prio = prio; 146 wq->wq_name = name; 147 wq->wq_func = callback_func; 148 wq->wq_arg = callback_arg; 149 } 150 151 static int 152 workqueue_initqueue(struct workqueue *wq, struct workqueue_queue *q, 153 int ipl, struct cpu_info *ci) 154 { 155 int error, ktf; 156 157 KASSERT(q->q_worker == NULL); 158 159 mutex_init(&q->q_mutex, MUTEX_DEFAULT, ipl); 160 cv_init(&q->q_cv, wq->wq_name); 161 SIMPLEQ_INIT(&q->q_queue); 162 ktf = ((wq->wq_flags & WQ_MPSAFE) != 0 ? KTHREAD_MPSAFE : 0); 163 if (ci) { 164 error = kthread_create(wq->wq_prio, ktf, ci, workqueue_worker, 165 wq, &q->q_worker, "%s/%u", wq->wq_name, ci->ci_index); 166 } else { 167 error = kthread_create(wq->wq_prio, ktf, ci, workqueue_worker, 168 wq, &q->q_worker, "%s", wq->wq_name); 169 } 170 if (error != 0) { 171 mutex_destroy(&q->q_mutex); 172 cv_destroy(&q->q_cv); 173 KASSERT(q->q_worker == NULL); 174 } 175 return error; 176 } 177 178 struct workqueue_exitargs { 179 work_impl_t wqe_wk; 180 struct workqueue_queue *wqe_q; 181 }; 182 183 static void 184 workqueue_exit(struct work *wk, void *arg) 185 { 186 struct workqueue_exitargs *wqe = (void *)wk; 187 struct workqueue_queue *q = wqe->wqe_q; 188 189 /* 190 * only competition at this point is workqueue_finiqueue. 191 */ 192 193 KASSERT(q->q_worker == curlwp); 194 KASSERT(SIMPLEQ_EMPTY(&q->q_queue)); 195 mutex_enter(&q->q_mutex); 196 q->q_worker = NULL; 197 cv_signal(&q->q_cv); 198 mutex_exit(&q->q_mutex); 199 kthread_exit(0); 200 } 201 202 static void 203 workqueue_finiqueue(struct workqueue *wq, struct workqueue_queue *q) 204 { 205 struct workqueue_exitargs wqe; 206 207 KASSERT(wq->wq_func == workqueue_exit); 208 209 wqe.wqe_q = q; 210 KASSERT(SIMPLEQ_EMPTY(&q->q_queue)); 211 KASSERT(q->q_worker != NULL); 212 mutex_enter(&q->q_mutex); 213 SIMPLEQ_INSERT_TAIL(&q->q_queue, &wqe.wqe_wk, wk_entry); 214 cv_signal(&q->q_cv); 215 while (q->q_worker != NULL) { 216 cv_wait(&q->q_cv, &q->q_mutex); 217 } 218 mutex_exit(&q->q_mutex); 219 mutex_destroy(&q->q_mutex); 220 cv_destroy(&q->q_cv); 221 } 222 223 /* --- */ 224 225 int 226 workqueue_create(struct workqueue **wqp, const char *name, 227 void (*callback_func)(struct work *, void *), void *callback_arg, 228 pri_t prio, int ipl, int flags) 229 { 230 struct workqueue *wq; 231 struct workqueue_queue *q; 232 void *ptr; 233 int error = 0; 234 235 CTASSERT(sizeof(work_impl_t) <= sizeof(struct work)); 236 237 ptr = kmem_zalloc(workqueue_size(flags), KM_SLEEP); 238 wq = (void *)roundup2((intptr_t)ptr, coherency_unit); 239 wq->wq_ptr = ptr; 240 wq->wq_flags = flags; 241 242 workqueue_init(wq, name, callback_func, callback_arg, prio, ipl); 243 244 if (flags & WQ_PERCPU) { 245 struct cpu_info *ci; 246 CPU_INFO_ITERATOR cii; 247 248 /* create the work-queue for each CPU */ 249 for (CPU_INFO_FOREACH(cii, ci)) { 250 q = workqueue_queue_lookup(wq, ci); 251 error = workqueue_initqueue(wq, q, ipl, ci); 252 if (error) { 253 break; 254 } 255 } 256 } else { 257 /* initialize a work-queue */ 258 q = workqueue_queue_lookup(wq, NULL); 259 error = workqueue_initqueue(wq, q, ipl, NULL); 260 } 261 262 if (error != 0) { 263 workqueue_destroy(wq); 264 } else { 265 *wqp = wq; 266 } 267 268 return error; 269 } 270 271 void 272 workqueue_destroy(struct workqueue *wq) 273 { 274 struct workqueue_queue *q; 275 struct cpu_info *ci; 276 CPU_INFO_ITERATOR cii; 277 278 wq->wq_func = workqueue_exit; 279 for (CPU_INFO_FOREACH(cii, ci)) { 280 q = workqueue_queue_lookup(wq, ci); 281 if (q->q_worker != NULL) { 282 workqueue_finiqueue(wq, q); 283 } 284 } 285 kmem_free(wq->wq_ptr, workqueue_size(wq->wq_flags)); 286 } 287 288 void 289 workqueue_enqueue(struct workqueue *wq, struct work *wk0, struct cpu_info *ci) 290 { 291 struct workqueue_queue *q; 292 work_impl_t *wk = (void *)wk0; 293 294 KASSERT(wq->wq_flags & WQ_PERCPU || ci == NULL); 295 q = workqueue_queue_lookup(wq, ci); 296 297 mutex_enter(&q->q_mutex); 298 SIMPLEQ_INSERT_TAIL(&q->q_queue, wk, wk_entry); 299 cv_signal(&q->q_cv); 300 mutex_exit(&q->q_mutex); 301 } 302