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, "tqlock"); 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 return EPIPE; 197 198 /* 199 * Count multiple enqueues. 200 */ 201 if (task->ta_pending) { 202 task->ta_pending++; 203 return 0; 204 } 205 206 /* 207 * Optimise the case when all tasks have the same priority. 208 */ 209 prev = STAILQ_LAST(&queue->tq_queue, task, ta_link); 210 if (!prev || prev->ta_priority >= task->ta_priority) { 211 STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link); 212 } else { 213 prev = NULL; 214 for (ins = STAILQ_FIRST(&queue->tq_queue); ins; 215 prev = ins, ins = STAILQ_NEXT(ins, ta_link)) 216 if (ins->ta_priority < task->ta_priority) 217 break; 218 219 if (prev) 220 STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link); 221 else 222 STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link); 223 } 224 225 task->ta_pending = 1; 226 if ((queue->tq_flags & TQ_FLAGS_BLOCKED) == 0) { 227 if (queue->tq_enqueue) 228 queue->tq_enqueue(queue->tq_context); 229 } else { 230 queue->tq_flags |= TQ_FLAGS_PENDING; 231 } 232 233 return 0; 234 } 235 236 int 237 taskqueue_enqueue(struct taskqueue *queue, struct task *task) 238 { 239 int res; 240 241 TQ_LOCK(queue); 242 res = taskqueue_enqueue_locked(queue, task); 243 TQ_UNLOCK(queue); 244 245 return (res); 246 } 247 248 static void 249 taskqueue_timeout_func(void *arg) 250 { 251 struct taskqueue *queue; 252 struct timeout_task *timeout_task; 253 254 timeout_task = arg; 255 queue = timeout_task->q; 256 KASSERT((timeout_task->f & DT_CALLOUT_ARMED) != 0, ("Stray timeout")); 257 timeout_task->f &= ~DT_CALLOUT_ARMED; 258 queue->tq_callouts--; 259 taskqueue_enqueue_locked(timeout_task->q, &timeout_task->t); 260 } 261 262 int 263 taskqueue_enqueue_timeout(struct taskqueue *queue, 264 struct timeout_task *timeout_task, int ticks) 265 { 266 int res; 267 268 TQ_LOCK(queue); 269 KASSERT(timeout_task->q == NULL || timeout_task->q == queue, 270 ("Migrated queue")); 271 timeout_task->q = queue; 272 res = timeout_task->t.ta_pending; 273 if (ticks == 0) { 274 taskqueue_enqueue_locked(queue, &timeout_task->t); 275 TQ_UNLOCK(queue); 276 } else { 277 if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) { 278 res++; 279 } else { 280 queue->tq_callouts++; 281 timeout_task->f |= DT_CALLOUT_ARMED; 282 } 283 TQ_UNLOCK(queue); 284 callout_reset(&timeout_task->c, ticks, taskqueue_timeout_func, 285 timeout_task); 286 } 287 return (res); 288 } 289 290 void 291 taskqueue_block(struct taskqueue *queue) 292 { 293 TQ_LOCK(queue); 294 queue->tq_flags |= TQ_FLAGS_BLOCKED; 295 TQ_UNLOCK(queue); 296 } 297 298 void 299 taskqueue_unblock(struct taskqueue *queue) 300 { 301 TQ_LOCK(queue); 302 queue->tq_flags &= ~TQ_FLAGS_BLOCKED; 303 if (queue->tq_flags & TQ_FLAGS_PENDING) { 304 queue->tq_flags &= ~TQ_FLAGS_PENDING; 305 if (queue->tq_enqueue) 306 queue->tq_enqueue(queue->tq_context); 307 } 308 TQ_UNLOCK(queue); 309 } 310 311 void 312 taskqueue_run(struct taskqueue *queue, int lock_held) 313 { 314 struct task *task; 315 int pending; 316 317 if (lock_held == 0) 318 TQ_LOCK(queue); 319 while (STAILQ_FIRST(&queue->tq_queue)) { 320 /* 321 * Carefully remove the first task from the queue and 322 * zero its pending count. 323 */ 324 task = STAILQ_FIRST(&queue->tq_queue); 325 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link); 326 pending = task->ta_pending; 327 task->ta_pending = 0; 328 queue->tq_running = task; 329 330 TQ_UNLOCK(queue); 331 task->ta_func(task->ta_context, pending); 332 queue->tq_running = NULL; 333 wakeup(task); 334 TQ_LOCK(queue); 335 } 336 if (lock_held == 0) 337 TQ_UNLOCK(queue); 338 } 339 340 static int 341 taskqueue_cancel_locked(struct taskqueue *queue, struct task *task, 342 u_int *pendp) 343 { 344 345 if (task->ta_pending > 0) 346 STAILQ_REMOVE(&queue->tq_queue, task, task, ta_link); 347 if (pendp != NULL) 348 *pendp = task->ta_pending; 349 task->ta_pending = 0; 350 return (task == queue->tq_running ? EBUSY : 0); 351 } 352 353 int 354 taskqueue_cancel(struct taskqueue *queue, struct task *task, u_int *pendp) 355 { 356 u_int pending; 357 int error; 358 359 TQ_LOCK(queue); 360 pending = task->ta_pending; 361 error = taskqueue_cancel_locked(queue, task, pendp); 362 TQ_UNLOCK(queue); 363 364 return (error); 365 } 366 367 int 368 taskqueue_cancel_timeout(struct taskqueue *queue, 369 struct timeout_task *timeout_task, u_int *pendp) 370 { 371 u_int pending, pending1; 372 int error; 373 374 pending = !!callout_stop(&timeout_task->c); 375 TQ_LOCK(queue); 376 error = taskqueue_cancel_locked(queue, &timeout_task->t, &pending1); 377 if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) { 378 timeout_task->f &= ~DT_CALLOUT_ARMED; 379 queue->tq_callouts--; 380 } 381 TQ_UNLOCK(queue); 382 383 if (pendp != NULL) 384 *pendp = pending + pending1; 385 return (error); 386 } 387 388 void 389 taskqueue_drain(struct taskqueue *queue, struct task *task) 390 { 391 TQ_LOCK(queue); 392 while (task->ta_pending != 0 || task == queue->tq_running) 393 TQ_SLEEP(queue, task, "-"); 394 TQ_UNLOCK(queue); 395 } 396 397 void 398 taskqueue_drain_timeout(struct taskqueue *queue, 399 struct timeout_task *timeout_task) 400 { 401 402 callout_stop_sync(&timeout_task->c); 403 taskqueue_drain(queue, &timeout_task->t); 404 } 405 406 static void 407 taskqueue_swi_enqueue(void *context) 408 { 409 setsofttq(); 410 } 411 412 static void 413 taskqueue_swi_run(void *arg, void *frame) 414 { 415 taskqueue_run(taskqueue_swi, 0); 416 } 417 418 static void 419 taskqueue_swi_mp_run(void *arg, void *frame) 420 { 421 taskqueue_run(taskqueue_swi_mp, 0); 422 } 423 424 int 425 taskqueue_start_threads(struct taskqueue **tqp, int count, int pri, int ncpu, 426 const char *fmt, ...) 427 { 428 __va_list ap; 429 struct thread *td; 430 struct taskqueue *tq; 431 int i, error, cpu; 432 char ktname[MAXCOMLEN]; 433 434 if (count <= 0) 435 return EINVAL; 436 437 tq = *tqp; 438 cpu = ncpu; 439 440 __va_start(ap, fmt); 441 kvsnprintf(ktname, MAXCOMLEN, fmt, ap); 442 __va_end(ap); 443 444 tq->tq_threads = kmalloc(sizeof(struct thread *) * count, M_TASKQUEUE, 445 M_WAITOK | M_ZERO); 446 447 for (i = 0; i < count; i++) { 448 /* 449 * If no specific cpu was specified and more than one thread 450 * is to be created, we distribute the threads amongst all 451 * cpus. 452 */ 453 if ((ncpu <= -1) && (count > 1)) 454 cpu = i%ncpus; 455 456 if (count == 1) { 457 error = lwkt_create(taskqueue_thread_loop, tqp, 458 &tq->tq_threads[i], NULL, 459 TDF_NOSTART, cpu, 460 "%s", ktname); 461 } else { 462 error = lwkt_create(taskqueue_thread_loop, tqp, 463 &tq->tq_threads[i], NULL, 464 TDF_NOSTART, cpu, 465 "%s_%d", ktname, i); 466 } 467 if (error) { 468 kprintf("%s: lwkt_create(%s): error %d", __func__, 469 ktname, error); 470 tq->tq_threads[i] = NULL; 471 } else { 472 td = tq->tq_threads[i]; 473 lwkt_setpri_initial(td, pri); 474 lwkt_schedule(td); 475 tq->tq_tcount++; 476 } 477 } 478 479 return 0; 480 } 481 482 void 483 taskqueue_thread_loop(void *arg) 484 { 485 struct taskqueue **tqp, *tq; 486 487 tqp = arg; 488 tq = *tqp; 489 TQ_LOCK(tq); 490 while ((tq->tq_flags & TQ_FLAGS_ACTIVE) != 0) { 491 taskqueue_run(tq, 1); 492 TQ_SLEEP(tq, tq, "tqthr"); 493 } 494 495 /* rendezvous with thread that asked us to terminate */ 496 tq->tq_tcount--; 497 TQ_UNLOCK(tq); 498 wakeup_one(tq->tq_threads); 499 lwkt_exit(); 500 } 501 502 void 503 taskqueue_thread_enqueue(void *context) 504 { 505 struct taskqueue **tqp, *tq; 506 507 tqp = context; 508 tq = *tqp; 509 510 wakeup_one(tq); 511 } 512 513 TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, 0, 514 register_swi(SWI_TQ, taskqueue_swi_run, NULL, "swi_taskq", NULL, -1)); 515 /* 516 * XXX: possibly use a different SWI_TQ_MP or so. 517 * related: sys/interrupt.h 518 * related: platform/XXX/isa/ipl_funcs.c 519 */ 520 TASKQUEUE_DEFINE(swi_mp, taskqueue_swi_enqueue, 0, 521 register_swi_mp(SWI_TQ, taskqueue_swi_mp_run, NULL, "swi_mp_taskq", NULL, 522 -1)); 523 524 struct taskqueue *taskqueue_thread[MAXCPU]; 525 526 static void 527 taskqueue_init(void) 528 { 529 int cpu; 530 531 lockinit(&taskqueue_queues_lock, "tqqueues", 0, 0); 532 STAILQ_INIT(&taskqueue_queues); 533 534 for (cpu = 0; cpu < ncpus; cpu++) { 535 taskqueue_thread[cpu] = taskqueue_create("thread", M_INTWAIT, 536 taskqueue_thread_enqueue, &taskqueue_thread[cpu]); 537 taskqueue_start_threads(&taskqueue_thread[cpu], 1, 538 TDPRI_KERN_DAEMON, cpu, "taskq_cpu %d", cpu); 539 } 540 } 541 542 SYSINIT(taskqueueinit, SI_SUB_PRE_DRIVERS, SI_ORDER_ANY, taskqueue_init, NULL); 543