1 /* $NetBSD: subr_workqueue.c,v 1.22 2007/12/05 07:06:54 ad 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 1.22 2007/12/05 07:06:54 ad 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 #ifdef MULTIPROCESSOR 67 #define CPU_ALIGN_SIZE CACHE_LINE_SIZE 68 #else 69 #define CPU_ALIGN_SIZE (ALIGNBYTES + 1) 70 #endif 71 72 #define WQ_SIZE (roundup2(sizeof(struct workqueue), CPU_ALIGN_SIZE)) 73 #define WQ_QUEUE_SIZE (roundup2(sizeof(struct workqueue_queue), CPU_ALIGN_SIZE)) 74 75 #define POISON 0xaabbccdd 76 77 static size_t 78 workqueue_size(int flags) 79 { 80 81 return WQ_SIZE 82 + ((flags & WQ_PERCPU) != 0 ? ncpu : 1) * WQ_QUEUE_SIZE 83 + CPU_ALIGN_SIZE; 84 } 85 86 static struct workqueue_queue * 87 workqueue_queue_lookup(struct workqueue *wq, struct cpu_info *ci) 88 { 89 u_int idx = 0; 90 91 if (wq->wq_flags & WQ_PERCPU) { 92 idx = ci ? cpu_index(ci) : cpu_index(curcpu()); 93 } 94 95 return (void *)((intptr_t)(wq) + WQ_SIZE + (idx * WQ_QUEUE_SIZE)); 96 } 97 98 static void 99 workqueue_runlist(struct workqueue *wq, struct workqhead *list) 100 { 101 work_impl_t *wk; 102 work_impl_t *next; 103 104 /* 105 * note that "list" is not a complete SIMPLEQ. 106 */ 107 108 for (wk = SIMPLEQ_FIRST(list); wk != NULL; wk = next) { 109 next = SIMPLEQ_NEXT(wk, wk_entry); 110 (*wq->wq_func)((void *)wk, wq->wq_arg); 111 } 112 } 113 114 static void 115 workqueue_worker(void *cookie) 116 { 117 struct workqueue *wq = cookie; 118 struct workqueue_queue *q; 119 120 /* find the workqueue of this kthread */ 121 q = workqueue_queue_lookup(wq, curlwp->l_cpu); 122 123 for (;;) { 124 struct workqhead tmp; 125 126 /* 127 * we violate abstraction of SIMPLEQ. 128 */ 129 130 #if defined(DIAGNOSTIC) 131 tmp.sqh_last = (void *)POISON; 132 #endif /* defined(DIAGNOSTIC) */ 133 134 mutex_enter(&q->q_mutex); 135 while (SIMPLEQ_EMPTY(&q->q_queue)) 136 cv_wait(&q->q_cv, &q->q_mutex); 137 tmp.sqh_first = q->q_queue.sqh_first; /* XXX */ 138 SIMPLEQ_INIT(&q->q_queue); 139 mutex_exit(&q->q_mutex); 140 141 workqueue_runlist(wq, &tmp); 142 } 143 } 144 145 static void 146 workqueue_init(struct workqueue *wq, const char *name, 147 void (*callback_func)(struct work *, void *), void *callback_arg, 148 pri_t prio, int ipl) 149 { 150 151 wq->wq_prio = prio; 152 wq->wq_name = name; 153 wq->wq_func = callback_func; 154 wq->wq_arg = callback_arg; 155 } 156 157 static int 158 workqueue_initqueue(struct workqueue *wq, struct workqueue_queue *q, 159 int ipl, struct cpu_info *ci) 160 { 161 int error, ktf; 162 163 KASSERT(q->q_worker == NULL); 164 165 mutex_init(&q->q_mutex, MUTEX_DEFAULT, ipl); 166 cv_init(&q->q_cv, wq->wq_name); 167 SIMPLEQ_INIT(&q->q_queue); 168 ktf = ((wq->wq_flags & WQ_MPSAFE) != 0 ? KTHREAD_MPSAFE : 0); 169 if (ci) { 170 error = kthread_create(wq->wq_prio, ktf, ci, workqueue_worker, 171 wq, &q->q_worker, "%s/%u", wq->wq_name, (u_int)ci->ci_cpuid); 172 } else { 173 error = kthread_create(wq->wq_prio, ktf, ci, workqueue_worker, 174 wq, &q->q_worker, "%s", wq->wq_name); 175 } 176 if (error != 0) { 177 mutex_destroy(&q->q_mutex); 178 cv_destroy(&q->q_cv); 179 KASSERT(q->q_worker == NULL); 180 } 181 return error; 182 } 183 184 struct workqueue_exitargs { 185 work_impl_t wqe_wk; 186 struct workqueue_queue *wqe_q; 187 }; 188 189 static void 190 workqueue_exit(struct work *wk, void *arg) 191 { 192 struct workqueue_exitargs *wqe = (void *)wk; 193 struct workqueue_queue *q = wqe->wqe_q; 194 195 /* 196 * only competition at this point is workqueue_finiqueue. 197 */ 198 199 KASSERT(q->q_worker == curlwp); 200 KASSERT(SIMPLEQ_EMPTY(&q->q_queue)); 201 mutex_enter(&q->q_mutex); 202 q->q_worker = NULL; 203 cv_signal(&q->q_cv); 204 mutex_exit(&q->q_mutex); 205 kthread_exit(0); 206 } 207 208 static void 209 workqueue_finiqueue(struct workqueue *wq, struct workqueue_queue *q) 210 { 211 struct workqueue_exitargs wqe; 212 213 KASSERT(wq->wq_func == workqueue_exit); 214 215 wqe.wqe_q = q; 216 KASSERT(SIMPLEQ_EMPTY(&q->q_queue)); 217 KASSERT(q->q_worker != NULL); 218 mutex_enter(&q->q_mutex); 219 SIMPLEQ_INSERT_TAIL(&q->q_queue, &wqe.wqe_wk, wk_entry); 220 cv_signal(&q->q_cv); 221 while (q->q_worker != NULL) { 222 cv_wait(&q->q_cv, &q->q_mutex); 223 } 224 mutex_exit(&q->q_mutex); 225 mutex_destroy(&q->q_mutex); 226 cv_destroy(&q->q_cv); 227 } 228 229 /* --- */ 230 231 int 232 workqueue_create(struct workqueue **wqp, const char *name, 233 void (*callback_func)(struct work *, void *), void *callback_arg, 234 pri_t prio, int ipl, int flags) 235 { 236 struct workqueue *wq; 237 struct workqueue_queue *q; 238 void *ptr; 239 int error = 0; 240 241 KASSERT(sizeof(work_impl_t) <= sizeof(struct work)); 242 243 ptr = kmem_zalloc(workqueue_size(flags), KM_SLEEP); 244 wq = (void *)roundup2((intptr_t)ptr, CPU_ALIGN_SIZE); 245 wq->wq_ptr = ptr; 246 wq->wq_flags = flags; 247 248 workqueue_init(wq, name, callback_func, callback_arg, prio, ipl); 249 250 if (flags & WQ_PERCPU) { 251 struct cpu_info *ci; 252 CPU_INFO_ITERATOR cii; 253 254 /* create the work-queue for each CPU */ 255 for (CPU_INFO_FOREACH(cii, ci)) { 256 q = workqueue_queue_lookup(wq, ci); 257 error = workqueue_initqueue(wq, q, ipl, ci); 258 if (error) { 259 break; 260 } 261 } 262 } else { 263 /* initialize a work-queue */ 264 q = workqueue_queue_lookup(wq, NULL); 265 error = workqueue_initqueue(wq, q, ipl, NULL); 266 } 267 268 if (error != 0) { 269 workqueue_destroy(wq); 270 } else { 271 *wqp = wq; 272 } 273 274 return error; 275 } 276 277 void 278 workqueue_destroy(struct workqueue *wq) 279 { 280 struct workqueue_queue *q; 281 struct cpu_info *ci; 282 CPU_INFO_ITERATOR cii; 283 284 wq->wq_func = workqueue_exit; 285 for (CPU_INFO_FOREACH(cii, ci)) { 286 q = workqueue_queue_lookup(wq, ci); 287 if (q->q_worker != NULL) { 288 workqueue_finiqueue(wq, q); 289 } 290 } 291 kmem_free(wq->wq_ptr, workqueue_size(wq->wq_flags)); 292 } 293 294 void 295 workqueue_enqueue(struct workqueue *wq, struct work *wk0, struct cpu_info *ci) 296 { 297 struct workqueue_queue *q; 298 work_impl_t *wk = (void *)wk0; 299 300 KASSERT(wq->wq_flags & WQ_PERCPU || ci == NULL); 301 q = workqueue_queue_lookup(wq, ci); 302 303 mutex_enter(&q->q_mutex); 304 SIMPLEQ_INSERT_TAIL(&q->q_queue, wk, wk_entry); 305 cv_signal(&q->q_cv); 306 mutex_exit(&q->q_mutex); 307 } 308