1 /*- 2 * Copyright (c) 2000 Doug Rabson 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27 #include <sys/cdefs.h> 28 __FBSDID("$FreeBSD$"); 29 30 #include <sys/param.h> 31 #include <sys/systm.h> 32 #include <sys/bus.h> 33 #include <sys/interrupt.h> 34 #include <sys/kernel.h> 35 #include <sys/kthread.h> 36 #include <sys/lock.h> 37 #include <sys/malloc.h> 38 #include <sys/mutex.h> 39 #include <sys/proc.h> 40 #include <sys/sched.h> 41 #include <sys/taskqueue.h> 42 #include <sys/unistd.h> 43 #include <machine/stdarg.h> 44 45 static MALLOC_DEFINE(M_TASKQUEUE, "taskqueue", "Task Queues"); 46 static void *taskqueue_giant_ih; 47 static void *taskqueue_ih; 48 static STAILQ_HEAD(taskqueue_list, taskqueue) taskqueue_queues; 49 static struct mtx taskqueue_queues_mutex; 50 51 struct taskqueue { 52 STAILQ_ENTRY(taskqueue) tq_link; 53 STAILQ_HEAD(, task) tq_queue; 54 const char *tq_name; 55 taskqueue_enqueue_fn tq_enqueue; 56 void *tq_context; 57 struct task *tq_running; 58 struct mtx tq_mutex; 59 struct proc **tq_pproc; 60 int tq_pcount; 61 int tq_spin; 62 int tq_flags; 63 }; 64 65 #define TQ_FLAGS_ACTIVE (1 << 0) 66 67 static __inline void 68 TQ_LOCK(struct taskqueue *tq) 69 { 70 if (tq->tq_spin) 71 mtx_lock_spin(&tq->tq_mutex); 72 else 73 mtx_lock(&tq->tq_mutex); 74 } 75 76 static __inline void 77 TQ_UNLOCK(struct taskqueue *tq) 78 { 79 if (tq->tq_spin) 80 mtx_unlock_spin(&tq->tq_mutex); 81 else 82 mtx_unlock(&tq->tq_mutex); 83 } 84 85 static void init_taskqueue_list(void *data); 86 87 static __inline int 88 TQ_SLEEP(struct taskqueue *tq, void *p, struct mtx *m, int pri, const char *wm, 89 int t) 90 { 91 if (tq->tq_spin) 92 return (msleep_spin(p, m, wm, t)); 93 return (msleep(p, m, pri, wm, t)); 94 } 95 96 static void 97 init_taskqueue_list(void *data __unused) 98 { 99 100 mtx_init(&taskqueue_queues_mutex, "taskqueue list", NULL, MTX_DEF); 101 STAILQ_INIT(&taskqueue_queues); 102 } 103 SYSINIT(taskqueue_list, SI_SUB_INTRINSIC, SI_ORDER_ANY, init_taskqueue_list, 104 NULL); 105 106 static struct taskqueue * 107 _taskqueue_create(const char *name, int mflags, 108 taskqueue_enqueue_fn enqueue, void *context, 109 int mtxflags, const char *mtxname) 110 { 111 struct taskqueue *queue; 112 113 queue = malloc(sizeof(struct taskqueue), M_TASKQUEUE, mflags | M_ZERO); 114 if (!queue) 115 return 0; 116 117 STAILQ_INIT(&queue->tq_queue); 118 queue->tq_name = name; 119 queue->tq_enqueue = enqueue; 120 queue->tq_context = context; 121 queue->tq_spin = (mtxflags & MTX_SPIN) != 0; 122 queue->tq_flags |= TQ_FLAGS_ACTIVE; 123 mtx_init(&queue->tq_mutex, mtxname, NULL, mtxflags); 124 125 mtx_lock(&taskqueue_queues_mutex); 126 STAILQ_INSERT_TAIL(&taskqueue_queues, queue, tq_link); 127 mtx_unlock(&taskqueue_queues_mutex); 128 129 return queue; 130 } 131 132 struct taskqueue * 133 taskqueue_create(const char *name, int mflags, 134 taskqueue_enqueue_fn enqueue, void *context) 135 { 136 return _taskqueue_create(name, mflags, enqueue, context, 137 MTX_DEF, "taskqueue"); 138 } 139 140 /* 141 * Signal a taskqueue thread to terminate. 142 */ 143 static void 144 taskqueue_terminate(struct proc **pp, struct taskqueue *tq) 145 { 146 147 while (tq->tq_pcount > 0) { 148 wakeup(tq); 149 TQ_SLEEP(tq, pp, &tq->tq_mutex, PWAIT, "taskqueue_destroy", 0); 150 } 151 } 152 153 void 154 taskqueue_free(struct taskqueue *queue) 155 { 156 157 mtx_lock(&taskqueue_queues_mutex); 158 STAILQ_REMOVE(&taskqueue_queues, queue, taskqueue, tq_link); 159 mtx_unlock(&taskqueue_queues_mutex); 160 161 TQ_LOCK(queue); 162 queue->tq_flags &= ~TQ_FLAGS_ACTIVE; 163 taskqueue_run(queue); 164 taskqueue_terminate(queue->tq_pproc, queue); 165 mtx_destroy(&queue->tq_mutex); 166 free(queue->tq_pproc, M_TASKQUEUE); 167 free(queue, M_TASKQUEUE); 168 } 169 170 /* 171 * Returns with the taskqueue locked. 172 */ 173 struct taskqueue * 174 taskqueue_find(const char *name) 175 { 176 struct taskqueue *queue; 177 178 mtx_lock(&taskqueue_queues_mutex); 179 STAILQ_FOREACH(queue, &taskqueue_queues, tq_link) { 180 if (strcmp(queue->tq_name, name) == 0) { 181 TQ_LOCK(queue); 182 mtx_unlock(&taskqueue_queues_mutex); 183 return queue; 184 } 185 } 186 mtx_unlock(&taskqueue_queues_mutex); 187 return NULL; 188 } 189 190 int 191 taskqueue_enqueue(struct taskqueue *queue, struct task *task) 192 { 193 struct task *ins; 194 struct task *prev; 195 196 TQ_LOCK(queue); 197 198 /* 199 * Count multiple enqueues. 200 */ 201 if (task->ta_pending) { 202 task->ta_pending++; 203 TQ_UNLOCK(queue); 204 return 0; 205 } 206 207 /* 208 * Optimise the case when all tasks have the same priority. 209 */ 210 prev = STAILQ_LAST(&queue->tq_queue, task, ta_link); 211 if (!prev || prev->ta_priority >= task->ta_priority) { 212 STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link); 213 } else { 214 prev = 0; 215 for (ins = STAILQ_FIRST(&queue->tq_queue); ins; 216 prev = ins, ins = STAILQ_NEXT(ins, ta_link)) 217 if (ins->ta_priority < task->ta_priority) 218 break; 219 220 if (prev) 221 STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link); 222 else 223 STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link); 224 } 225 226 task->ta_pending = 1; 227 queue->tq_enqueue(queue->tq_context); 228 229 TQ_UNLOCK(queue); 230 231 return 0; 232 } 233 234 void 235 taskqueue_run(struct taskqueue *queue) 236 { 237 struct task *task; 238 int owned, pending; 239 240 owned = mtx_owned(&queue->tq_mutex); 241 if (!owned) 242 TQ_LOCK(queue); 243 while (STAILQ_FIRST(&queue->tq_queue)) { 244 /* 245 * Carefully remove the first task from the queue and 246 * zero its pending count. 247 */ 248 task = STAILQ_FIRST(&queue->tq_queue); 249 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link); 250 pending = task->ta_pending; 251 task->ta_pending = 0; 252 queue->tq_running = task; 253 TQ_UNLOCK(queue); 254 255 task->ta_func(task->ta_context, pending); 256 257 TQ_LOCK(queue); 258 queue->tq_running = NULL; 259 wakeup(task); 260 } 261 262 /* 263 * For compatibility, unlock on return if the queue was not locked 264 * on entry, although this opens a race window. 265 */ 266 if (!owned) 267 TQ_UNLOCK(queue); 268 } 269 270 void 271 taskqueue_drain(struct taskqueue *queue, struct task *task) 272 { 273 if (queue->tq_spin) { /* XXX */ 274 mtx_lock_spin(&queue->tq_mutex); 275 while (task->ta_pending != 0 || task == queue->tq_running) 276 msleep_spin(task, &queue->tq_mutex, "-", 0); 277 mtx_unlock_spin(&queue->tq_mutex); 278 } else { 279 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__); 280 281 mtx_lock(&queue->tq_mutex); 282 while (task->ta_pending != 0 || task == queue->tq_running) 283 msleep(task, &queue->tq_mutex, PWAIT, "-", 0); 284 mtx_unlock(&queue->tq_mutex); 285 } 286 } 287 288 static void 289 taskqueue_swi_enqueue(void *context) 290 { 291 swi_sched(taskqueue_ih, 0); 292 } 293 294 static void 295 taskqueue_swi_run(void *dummy) 296 { 297 taskqueue_run(taskqueue_swi); 298 } 299 300 static void 301 taskqueue_swi_giant_enqueue(void *context) 302 { 303 swi_sched(taskqueue_giant_ih, 0); 304 } 305 306 static void 307 taskqueue_swi_giant_run(void *dummy) 308 { 309 taskqueue_run(taskqueue_swi_giant); 310 } 311 312 int 313 taskqueue_start_threads(struct taskqueue **tqp, int count, int pri, 314 const char *name, ...) 315 { 316 va_list ap; 317 struct taskqueue *tq; 318 struct thread *td; 319 char ktname[MAXCOMLEN]; 320 int i, error; 321 322 if (count <= 0) 323 return (EINVAL); 324 tq = *tqp; 325 326 va_start(ap, name); 327 vsnprintf(ktname, MAXCOMLEN, name, ap); 328 va_end(ap); 329 330 tq->tq_pproc = malloc(sizeof(struct proc *) * count, M_TASKQUEUE, 331 M_NOWAIT | M_ZERO); 332 if (tq->tq_pproc == NULL) { 333 printf("%s: no memory for %s threads\n", __func__, ktname); 334 return (ENOMEM); 335 } 336 337 for (i = 0; i < count; i++) { 338 if (count == 1) 339 error = kthread_create(taskqueue_thread_loop, tqp, 340 &tq->tq_pproc[i], RFSTOPPED, 0, ktname); 341 else 342 error = kthread_create(taskqueue_thread_loop, tqp, 343 &tq->tq_pproc[i], RFSTOPPED, 0, "%s_%d", ktname, i); 344 if (error) { 345 /* should be ok to continue, taskqueue_free will dtrt */ 346 printf("%s: kthread_create(%s): error %d", 347 __func__, ktname, error); 348 tq->tq_pproc[i] = NULL; /* paranoid */ 349 } else 350 tq->tq_pcount++; 351 } 352 mtx_lock_spin(&sched_lock); 353 for (i = 0; i < count; i++) { 354 if (tq->tq_pproc[i] == NULL) 355 continue; 356 td = FIRST_THREAD_IN_PROC(tq->tq_pproc[i]); 357 sched_prio(td, pri); 358 sched_add(td, SRQ_BORING); 359 } 360 mtx_unlock_spin(&sched_lock); 361 362 return (0); 363 } 364 365 void 366 taskqueue_thread_loop(void *arg) 367 { 368 struct taskqueue **tqp, *tq; 369 370 tqp = arg; 371 tq = *tqp; 372 TQ_LOCK(tq); 373 do { 374 taskqueue_run(tq); 375 TQ_SLEEP(tq, tq, &tq->tq_mutex, 0, "-", 0); 376 } while ((tq->tq_flags & TQ_FLAGS_ACTIVE) != 0); 377 378 /* rendezvous with thread that asked us to terminate */ 379 tq->tq_pcount--; 380 wakeup_one(tq->tq_pproc); 381 TQ_UNLOCK(tq); 382 kthread_exit(0); 383 } 384 385 void 386 taskqueue_thread_enqueue(void *context) 387 { 388 struct taskqueue **tqp, *tq; 389 390 tqp = context; 391 tq = *tqp; 392 393 mtx_assert(&tq->tq_mutex, MA_OWNED); 394 wakeup_one(tq); 395 } 396 397 TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, 0, 398 swi_add(NULL, "task queue", taskqueue_swi_run, NULL, SWI_TQ, 399 INTR_MPSAFE, &taskqueue_ih)); 400 401 TASKQUEUE_DEFINE(swi_giant, taskqueue_swi_giant_enqueue, 0, 402 swi_add(NULL, "Giant taskq", taskqueue_swi_giant_run, 403 NULL, SWI_TQ_GIANT, 0, &taskqueue_giant_ih)); 404 405 TASKQUEUE_DEFINE_THREAD(thread); 406 407 struct taskqueue * 408 taskqueue_create_fast(const char *name, int mflags, 409 taskqueue_enqueue_fn enqueue, void *context) 410 { 411 return _taskqueue_create(name, mflags, enqueue, context, 412 MTX_SPIN, "fast_taskqueue"); 413 } 414 415 /* NB: for backwards compatibility */ 416 int 417 taskqueue_enqueue_fast(struct taskqueue *queue, struct task *task) 418 { 419 return taskqueue_enqueue(queue, task); 420 } 421 422 static void *taskqueue_fast_ih; 423 424 static void 425 taskqueue_fast_enqueue(void *context) 426 { 427 swi_sched(taskqueue_fast_ih, 0); 428 } 429 430 static void 431 taskqueue_fast_run(void *dummy) 432 { 433 taskqueue_run(taskqueue_fast); 434 } 435 436 TASKQUEUE_FAST_DEFINE(fast, taskqueue_fast_enqueue, 0, 437 swi_add(NULL, "Fast task queue", taskqueue_fast_run, NULL, 438 SWI_TQ_FAST, INTR_MPSAFE, &taskqueue_fast_ih)); 439