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 * $FreeBSD: src/sys/kern/subr_taskqueue.c,v 1.69 2012/08/28 13:35:37 jhb Exp $" 27 */ 28 29 #include <sys/param.h> 30 #include <sys/queue.h> 31 #include <sys/systm.h> 32 #include <sys/kernel.h> 33 #include <sys/taskqueue.h> 34 #include <sys/interrupt.h> 35 #include <sys/lock.h> 36 #include <sys/malloc.h> 37 #include <sys/kthread.h> 38 #include <sys/thread2.h> 39 #include <sys/spinlock.h> 40 #include <sys/spinlock2.h> 41 #include <sys/serialize.h> 42 #include <sys/proc.h> 43 #include <machine/varargs.h> 44 45 MALLOC_DEFINE(M_TASKQUEUE, "taskqueue", "Task Queues"); 46 47 static STAILQ_HEAD(taskqueue_list, taskqueue) taskqueue_queues; 48 static struct lock taskqueue_queues_lock; 49 50 struct taskqueue { 51 STAILQ_ENTRY(taskqueue) tq_link; 52 STAILQ_HEAD(, task) tq_queue; 53 const char *tq_name; 54 taskqueue_enqueue_fn tq_enqueue; 55 void *tq_context; 56 57 struct task *tq_running; 58 struct spinlock tq_lock; 59 struct thread **tq_threads; 60 int tq_tcount; 61 int tq_flags; 62 int tq_callouts; 63 }; 64 65 #define TQ_FLAGS_ACTIVE (1 << 0) 66 #define TQ_FLAGS_BLOCKED (1 << 1) 67 #define TQ_FLAGS_PENDING (1 << 2) 68 69 #define DT_CALLOUT_ARMED (1 << 0) 70 71 void 72 _timeout_task_init(struct taskqueue *queue, struct timeout_task *timeout_task, 73 int priority, task_fn_t func, void *context) 74 { 75 76 TASK_INIT(&timeout_task->t, priority, func, context); 77 callout_init(&timeout_task->c); 78 timeout_task->q = queue; 79 timeout_task->f = 0; 80 } 81 82 static void taskqueue_run(struct taskqueue *queue, int lock_held); 83 84 static __inline void 85 TQ_LOCK_INIT(struct taskqueue *tq) 86 { 87 spin_init(&tq->tq_lock); 88 } 89 90 static __inline void 91 TQ_LOCK_UNINIT(struct taskqueue *tq) 92 { 93 spin_uninit(&tq->tq_lock); 94 } 95 96 static __inline void 97 TQ_LOCK(struct taskqueue *tq) 98 { 99 spin_lock(&tq->tq_lock); 100 } 101 102 static __inline void 103 TQ_UNLOCK(struct taskqueue *tq) 104 { 105 spin_unlock(&tq->tq_lock); 106 } 107 108 static __inline void 109 TQ_SLEEP(struct taskqueue *tq, void *ident, const char *wmesg) 110 { 111 ssleep(ident, &tq->tq_lock, 0, wmesg, 0); 112 } 113 114 struct taskqueue * 115 taskqueue_create(const char *name, int mflags, 116 taskqueue_enqueue_fn enqueue, void *context) 117 { 118 struct taskqueue *queue; 119 120 queue = kmalloc(sizeof(*queue), M_TASKQUEUE, mflags | M_ZERO); 121 if (!queue) 122 return NULL; 123 STAILQ_INIT(&queue->tq_queue); 124 queue->tq_name = name; 125 queue->tq_enqueue = enqueue; 126 queue->tq_context = context; 127 queue->tq_flags |= TQ_FLAGS_ACTIVE; 128 TQ_LOCK_INIT(queue); 129 130 lockmgr(&taskqueue_queues_lock, LK_EXCLUSIVE); 131 STAILQ_INSERT_TAIL(&taskqueue_queues, queue, tq_link); 132 lockmgr(&taskqueue_queues_lock, LK_RELEASE); 133 134 return queue; 135 } 136 137 static void 138 taskqueue_terminate(struct thread **pp, struct taskqueue *tq) 139 { 140 while(tq->tq_tcount > 0) { 141 wakeup(tq); 142 TQ_SLEEP(tq, pp, "taskqueue_terminate"); 143 } 144 } 145 146 void 147 taskqueue_free(struct taskqueue *queue) 148 { 149 TQ_LOCK(queue); 150 queue->tq_flags &= ~TQ_FLAGS_ACTIVE; 151 taskqueue_run(queue, 1); 152 taskqueue_terminate(queue->tq_threads, queue); 153 TQ_UNLOCK(queue); 154 155 lockmgr(&taskqueue_queues_lock, LK_EXCLUSIVE); 156 STAILQ_REMOVE(&taskqueue_queues, queue, taskqueue, tq_link); 157 lockmgr(&taskqueue_queues_lock, LK_RELEASE); 158 159 TQ_LOCK_UNINIT(queue); 160 161 kfree(queue, M_TASKQUEUE); 162 } 163 164 struct taskqueue * 165 taskqueue_find(const char *name) 166 { 167 struct taskqueue *queue; 168 169 lockmgr(&taskqueue_queues_lock, LK_EXCLUSIVE); 170 STAILQ_FOREACH(queue, &taskqueue_queues, tq_link) { 171 if (!strcmp(queue->tq_name, name)) { 172 lockmgr(&taskqueue_queues_lock, LK_RELEASE); 173 return queue; 174 } 175 } 176 lockmgr(&taskqueue_queues_lock, LK_RELEASE); 177 return NULL; 178 } 179 180 /* 181 * NOTE! If using the per-cpu taskqueues ``taskqueue_thread[mycpuid]'', 182 * be sure NOT TO SHARE the ``task'' between CPUs. TASKS ARE NOT LOCKED. 183 * So either use a throwaway task which will only be enqueued once, or 184 * use one task per CPU! 185 */ 186 static int 187 taskqueue_enqueue_locked(struct taskqueue *queue, struct task *task) 188 { 189 struct task *ins; 190 struct task *prev; 191 192 /* 193 * Don't allow new tasks on a queue which is being freed. 194 */ 195 if ((queue->tq_flags & TQ_FLAGS_ACTIVE) == 0) { 196 TQ_UNLOCK(queue); 197 return EPIPE; 198 } 199 200 /* 201 * Count multiple enqueues. 202 */ 203 if (task->ta_pending) { 204 task->ta_pending++; 205 return 0; 206 } 207 208 /* 209 * Optimise the case when all tasks have the same priority. 210 */ 211 prev = STAILQ_LAST(&queue->tq_queue, task, ta_link); 212 if (!prev || prev->ta_priority >= task->ta_priority) { 213 STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link); 214 } else { 215 prev = NULL; 216 for (ins = STAILQ_FIRST(&queue->tq_queue); ins; 217 prev = ins, ins = STAILQ_NEXT(ins, ta_link)) 218 if (ins->ta_priority < task->ta_priority) 219 break; 220 221 if (prev) 222 STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link); 223 else 224 STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link); 225 } 226 227 task->ta_pending = 1; 228 if ((queue->tq_flags & TQ_FLAGS_BLOCKED) == 0) { 229 if (queue->tq_enqueue) 230 queue->tq_enqueue(queue->tq_context); 231 } else { 232 queue->tq_flags |= TQ_FLAGS_PENDING; 233 } 234 235 return 0; 236 } 237 238 int 239 taskqueue_enqueue(struct taskqueue *queue, struct task *task) 240 { 241 int res; 242 243 TQ_LOCK(queue); 244 res = taskqueue_enqueue_locked(queue, task); 245 TQ_UNLOCK(queue); 246 247 return (res); 248 } 249 250 static void 251 taskqueue_timeout_func(void *arg) 252 { 253 struct taskqueue *queue; 254 struct timeout_task *timeout_task; 255 256 timeout_task = arg; 257 queue = timeout_task->q; 258 KASSERT((timeout_task->f & DT_CALLOUT_ARMED) != 0, ("Stray timeout")); 259 timeout_task->f &= ~DT_CALLOUT_ARMED; 260 queue->tq_callouts--; 261 taskqueue_enqueue_locked(timeout_task->q, &timeout_task->t); 262 } 263 264 int 265 taskqueue_enqueue_timeout(struct taskqueue *queue, 266 struct timeout_task *timeout_task, int ticks) 267 { 268 int res; 269 270 TQ_LOCK(queue); 271 KASSERT(timeout_task->q == NULL || timeout_task->q == queue, 272 ("Migrated queue")); 273 timeout_task->q = queue; 274 res = timeout_task->t.ta_pending; 275 if (ticks == 0) { 276 taskqueue_enqueue_locked(queue, &timeout_task->t); 277 } else { 278 if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) { 279 res++; 280 } else { 281 queue->tq_callouts++; 282 timeout_task->f |= DT_CALLOUT_ARMED; 283 } 284 callout_reset(&timeout_task->c, ticks, taskqueue_timeout_func, 285 timeout_task); 286 } 287 TQ_UNLOCK(queue); 288 return (res); 289 } 290 291 void 292 taskqueue_block(struct taskqueue *queue) 293 { 294 TQ_LOCK(queue); 295 queue->tq_flags |= TQ_FLAGS_BLOCKED; 296 TQ_UNLOCK(queue); 297 } 298 299 void 300 taskqueue_unblock(struct taskqueue *queue) 301 { 302 TQ_LOCK(queue); 303 queue->tq_flags &= ~TQ_FLAGS_BLOCKED; 304 if (queue->tq_flags & TQ_FLAGS_PENDING) { 305 queue->tq_flags &= ~TQ_FLAGS_PENDING; 306 if (queue->tq_enqueue) 307 queue->tq_enqueue(queue->tq_context); 308 } 309 TQ_UNLOCK(queue); 310 } 311 312 void 313 taskqueue_run(struct taskqueue *queue, int lock_held) 314 { 315 struct task *task; 316 int pending; 317 318 if (lock_held == 0) 319 TQ_LOCK(queue); 320 while (STAILQ_FIRST(&queue->tq_queue)) { 321 /* 322 * Carefully remove the first task from the queue and 323 * zero its pending count. 324 */ 325 task = STAILQ_FIRST(&queue->tq_queue); 326 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link); 327 pending = task->ta_pending; 328 task->ta_pending = 0; 329 queue->tq_running = task; 330 TQ_UNLOCK(queue); 331 332 task->ta_func(task->ta_context, pending); 333 334 TQ_LOCK(queue); 335 queue->tq_running = NULL; 336 wakeup(task); 337 } 338 if (lock_held == 0) 339 TQ_UNLOCK(queue); 340 } 341 342 static int 343 taskqueue_cancel_locked(struct taskqueue *queue, struct task *task, 344 u_int *pendp) 345 { 346 347 if (task->ta_pending > 0) 348 STAILQ_REMOVE(&queue->tq_queue, task, task, ta_link); 349 if (pendp != NULL) 350 *pendp = task->ta_pending; 351 task->ta_pending = 0; 352 return (task == queue->tq_running ? EBUSY : 0); 353 } 354 355 int 356 taskqueue_cancel(struct taskqueue *queue, struct task *task, u_int *pendp) 357 { 358 u_int pending; 359 int error; 360 361 TQ_LOCK(queue); 362 pending = task->ta_pending; 363 error = taskqueue_cancel_locked(queue, task, pendp); 364 TQ_UNLOCK(queue); 365 366 return (error); 367 } 368 369 int 370 taskqueue_cancel_timeout(struct taskqueue *queue, 371 struct timeout_task *timeout_task, u_int *pendp) 372 { 373 u_int pending, pending1; 374 int error; 375 376 TQ_LOCK(queue); 377 pending = !!callout_stop(&timeout_task->c); 378 error = taskqueue_cancel_locked(queue, &timeout_task->t, &pending1); 379 if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) { 380 timeout_task->f &= ~DT_CALLOUT_ARMED; 381 queue->tq_callouts--; 382 } 383 TQ_UNLOCK(queue); 384 385 if (pendp != NULL) 386 *pendp = pending + pending1; 387 return (error); 388 } 389 390 void 391 taskqueue_drain(struct taskqueue *queue, struct task *task) 392 { 393 TQ_LOCK(queue); 394 while (task->ta_pending != 0 || task == queue->tq_running) 395 TQ_SLEEP(queue, task, "-"); 396 TQ_UNLOCK(queue); 397 } 398 399 void 400 taskqueue_drain_timeout(struct taskqueue *queue, 401 struct timeout_task *timeout_task) 402 { 403 404 callout_stop_sync(&timeout_task->c); 405 taskqueue_drain(queue, &timeout_task->t); 406 } 407 408 static void 409 taskqueue_swi_enqueue(void *context) 410 { 411 setsofttq(); 412 } 413 414 static void 415 taskqueue_swi_run(void *arg, void *frame) 416 { 417 taskqueue_run(taskqueue_swi, 0); 418 } 419 420 static void 421 taskqueue_swi_mp_run(void *arg, void *frame) 422 { 423 taskqueue_run(taskqueue_swi_mp, 0); 424 } 425 426 int 427 taskqueue_start_threads(struct taskqueue **tqp, int count, int pri, int ncpu, 428 const char *fmt, ...) 429 { 430 __va_list ap; 431 struct thread *td; 432 struct taskqueue *tq; 433 int i, error, cpu; 434 char ktname[MAXCOMLEN]; 435 436 if (count <= 0) 437 return EINVAL; 438 439 tq = *tqp; 440 cpu = ncpu; 441 442 __va_start(ap, fmt); 443 kvsnprintf(ktname, MAXCOMLEN, fmt, ap); 444 __va_end(ap); 445 446 tq->tq_threads = kmalloc(sizeof(struct thread *) * count, M_TASKQUEUE, 447 M_WAITOK | M_ZERO); 448 449 for (i = 0; i < count; i++) { 450 /* 451 * If no specific cpu was specified and more than one thread 452 * is to be created, we distribute the threads amongst all 453 * cpus. 454 */ 455 if ((ncpu <= -1) && (count > 1)) 456 cpu = i%ncpus; 457 458 if (count == 1) { 459 error = lwkt_create(taskqueue_thread_loop, tqp, 460 &tq->tq_threads[i], NULL, 461 TDF_NOSTART, cpu, 462 "%s", ktname); 463 } else { 464 error = lwkt_create(taskqueue_thread_loop, tqp, 465 &tq->tq_threads[i], NULL, 466 TDF_NOSTART, cpu, 467 "%s_%d", ktname, i); 468 } 469 if (error) { 470 kprintf("%s: lwkt_create(%s): error %d", __func__, 471 ktname, error); 472 tq->tq_threads[i] = NULL; 473 } else { 474 td = tq->tq_threads[i]; 475 lwkt_setpri_initial(td, pri); 476 lwkt_schedule(td); 477 tq->tq_tcount++; 478 } 479 } 480 481 return 0; 482 } 483 484 void 485 taskqueue_thread_loop(void *arg) 486 { 487 struct taskqueue **tqp, *tq; 488 489 tqp = arg; 490 tq = *tqp; 491 TQ_LOCK(tq); 492 while ((tq->tq_flags & TQ_FLAGS_ACTIVE) != 0) { 493 taskqueue_run(tq, 1); 494 TQ_SLEEP(tq, tq, "tqthr"); 495 } 496 497 /* rendezvous with thread that asked us to terminate */ 498 tq->tq_tcount--; 499 wakeup_one(tq->tq_threads); 500 TQ_UNLOCK(tq); 501 lwkt_exit(); 502 } 503 504 void 505 taskqueue_thread_enqueue(void *context) 506 { 507 struct taskqueue **tqp, *tq; 508 509 tqp = context; 510 tq = *tqp; 511 512 wakeup_one(tq); 513 } 514 515 TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, 0, 516 register_swi(SWI_TQ, taskqueue_swi_run, NULL, "swi_taskq", NULL, -1)); 517 /* 518 * XXX: possibly use a different SWI_TQ_MP or so. 519 * related: sys/interrupt.h 520 * related: platform/XXX/isa/ipl_funcs.c 521 */ 522 TASKQUEUE_DEFINE(swi_mp, taskqueue_swi_enqueue, 0, 523 register_swi_mp(SWI_TQ, taskqueue_swi_mp_run, NULL, "swi_mp_taskq", NULL, 524 -1)); 525 526 struct taskqueue *taskqueue_thread[MAXCPU]; 527 528 static void 529 taskqueue_init(void) 530 { 531 int cpu; 532 533 lockinit(&taskqueue_queues_lock, "tqqueues", 0, 0); 534 STAILQ_INIT(&taskqueue_queues); 535 536 for (cpu = 0; cpu < ncpus; cpu++) { 537 taskqueue_thread[cpu] = taskqueue_create("thread", M_INTWAIT, 538 taskqueue_thread_enqueue, &taskqueue_thread[cpu]); 539 taskqueue_start_threads(&taskqueue_thread[cpu], 1, 540 TDPRI_KERN_DAEMON, cpu, "taskq_cpu %d", cpu); 541 } 542 } 543 544 SYSINIT(taskqueueinit, SI_SUB_PRE_DRIVERS, SI_ORDER_ANY, taskqueue_init, NULL); 545