| 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 | static 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 | int error; |
| 357 | |
| 358 | TQ_LOCK(queue); |
| 359 | error = taskqueue_cancel_locked(queue, task, pendp); |
| 360 | TQ_UNLOCK(queue); |
| 361 | |
| 362 | return (error); |
| 363 | } |
| 364 | |
| 365 | int |
| 366 | taskqueue_cancel_timeout(struct taskqueue *queue, |
| 367 | struct timeout_task *timeout_task, u_int *pendp) |
| 368 | { |
| 369 | u_int pending, pending1; |
| 370 | int error; |
| 371 | |
| 372 | pending = !!callout_stop(&timeout_task->c); |
| 373 | TQ_LOCK(queue); |
| 374 | error = taskqueue_cancel_locked(queue, &timeout_task->t, &pending1); |
| 375 | if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) { |
| 376 | timeout_task->f &= ~DT_CALLOUT_ARMED; |
| 377 | queue->tq_callouts--; |
| 378 | } |
| 379 | TQ_UNLOCK(queue); |
| 380 | |
| 381 | if (pendp != NULL) |
| 382 | *pendp = pending + pending1; |
| 383 | return (error); |
| 384 | } |
| 385 | |
| 386 | void |
| 387 | taskqueue_drain(struct taskqueue *queue, struct task *task) |
| 388 | { |
| 389 | TQ_LOCK(queue); |
| 390 | while (task->ta_pending != 0 || task == queue->tq_running) |
| 391 | TQ_SLEEP(queue, task, "-"); |
| 392 | TQ_UNLOCK(queue); |
| 393 | } |
| 394 | |
| 395 | void |
| 396 | taskqueue_drain_timeout(struct taskqueue *queue, |
| 397 | struct timeout_task *timeout_task) |
| 398 | { |
| 399 | |
| 400 | callout_stop_sync(&timeout_task->c); |
| 401 | taskqueue_drain(queue, &timeout_task->t); |
| 402 | } |
| 403 | |
| 404 | static void |
| 405 | taskqueue_swi_enqueue(void *context) |
| 406 | { |
| 407 | setsofttq(); |
| 408 | } |
| 409 | |
| 410 | static void |
| 411 | taskqueue_swi_run(void *arg, void *frame) |
| 412 | { |
| 413 | taskqueue_run(taskqueue_swi, 0); |
| 414 | } |
| 415 | |
| 416 | static void |
| 417 | taskqueue_swi_mp_run(void *arg, void *frame) |
| 418 | { |
| 419 | taskqueue_run(taskqueue_swi_mp, 0); |
| 420 | } |
| 421 | |
| 422 | int |
| 423 | taskqueue_start_threads(struct taskqueue **tqp, int count, int pri, int ncpu, |
| 424 | const char *fmt, ...) |
| 425 | { |
| 426 | __va_list ap; |
| 427 | struct thread *td; |
| 428 | struct taskqueue *tq; |
| 429 | int i, error, cpu; |
| 430 | char ktname[MAXCOMLEN]; |
| 431 | |
| 432 | if (count <= 0) |
| 433 | return EINVAL; |
| 434 | |
| 435 | tq = *tqp; |
| 436 | cpu = ncpu; |
| 437 | |
| 438 | __va_start(ap, fmt); |
| 439 | kvsnprintf(ktname, MAXCOMLEN, fmt, ap); |
| 440 | __va_end(ap); |
| 441 | |
| 442 | tq->tq_threads = kmalloc(sizeof(struct thread *) * count, M_TASKQUEUE, |
| 443 | M_WAITOK | M_ZERO); |
| 444 | |
| 445 | for (i = 0; i < count; i++) { |
| 446 | /* |
| 447 | * If no specific cpu was specified and more than one thread |
| 448 | * is to be created, we distribute the threads amongst all |
| 449 | * cpus. |
| 450 | */ |
| 451 | if ((ncpu <= -1) && (count > 1)) |
| 452 | cpu = i%ncpus; |
| 453 | |
| 454 | if (count == 1) { |
| 455 | error = lwkt_create(taskqueue_thread_loop, tqp, |
| 456 | &tq->tq_threads[i], NULL, |
| 457 | TDF_NOSTART, cpu, |
| 458 | "%s", ktname); |
| 459 | } else { |
| 460 | error = lwkt_create(taskqueue_thread_loop, tqp, |
| 461 | &tq->tq_threads[i], NULL, |
| 462 | TDF_NOSTART, cpu, |
| 463 | "%s_%d", ktname, i); |
| 464 | } |
| 465 | if (error) { |
| 466 | kprintf("%s: lwkt_create(%s): error %d", __func__, |
| 467 | ktname, error); |
| 468 | tq->tq_threads[i] = NULL; |
| 469 | } else { |
| 470 | td = tq->tq_threads[i]; |
| 471 | lwkt_setpri_initial(td, pri); |
| 472 | lwkt_schedule(td); |
| 473 | tq->tq_tcount++; |
| 474 | } |
| 475 | } |
| 476 | |
| 477 | return 0; |
| 478 | } |
| 479 | |
| 480 | void |
| 481 | taskqueue_thread_loop(void *arg) |
| 482 | { |
| 483 | struct taskqueue **tqp, *tq; |
| 484 | |
| 485 | tqp = arg; |
| 486 | tq = *tqp; |
| 487 | TQ_LOCK(tq); |
| 488 | while ((tq->tq_flags & TQ_FLAGS_ACTIVE) != 0) { |
| 489 | taskqueue_run(tq, 1); |
| 490 | TQ_SLEEP(tq, tq, "tqthr"); |
| 491 | } |
| 492 | |
| 493 | /* rendezvous with thread that asked us to terminate */ |
| 494 | tq->tq_tcount--; |
| 495 | TQ_UNLOCK(tq); |
| 496 | wakeup_one(tq->tq_threads); |
| 497 | lwkt_exit(); |
| 498 | } |
| 499 | |
| 500 | void |
| 501 | taskqueue_thread_enqueue(void *context) |
| 502 | { |
| 503 | struct taskqueue **tqp, *tq; |
| 504 | |
| 505 | tqp = context; |
| 506 | tq = *tqp; |
| 507 | |
| 508 | wakeup_one(tq); |
| 509 | } |
| 510 | |
| 511 | TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, 0, |
| 512 | register_swi(SWI_TQ, taskqueue_swi_run, NULL, "swi_taskq", NULL, -1)); |
| 513 | /* |
| 514 | * XXX: possibly use a different SWI_TQ_MP or so. |
| 515 | * related: sys/interrupt.h |
| 516 | * related: platform/XXX/isa/ipl_funcs.c |
| 517 | */ |
| 518 | TASKQUEUE_DEFINE(swi_mp, taskqueue_swi_enqueue, 0, |
| 519 | register_swi_mp(SWI_TQ, taskqueue_swi_mp_run, NULL, "swi_mp_taskq", NULL, |
| 520 | -1)); |
| 521 | |
| 522 | struct taskqueue *taskqueue_thread[MAXCPU]; |
| 523 | |
| 524 | static void |
| 525 | taskqueue_init(void) |
| 526 | { |
| 527 | int cpu; |
| 528 | |
| 529 | lockinit(&taskqueue_queues_lock, "tqqueues", 0, 0); |
| 530 | STAILQ_INIT(&taskqueue_queues); |
| 531 | |
| 532 | for (cpu = 0; cpu < ncpus; cpu++) { |
| 533 | taskqueue_thread[cpu] = taskqueue_create("thread", M_INTWAIT, |
| 534 | taskqueue_thread_enqueue, &taskqueue_thread[cpu]); |
| 535 | taskqueue_start_threads(&taskqueue_thread[cpu], 1, |
| 536 | TDPRI_KERN_DAEMON, cpu, "taskq_cpu %d", cpu); |
| 537 | } |
| 538 | } |
| 539 | |
| 540 | SYSINIT(taskqueueinit, SI_SUB_PRE_DRIVERS, SI_ORDER_ANY, taskqueue_init, NULL); |