sys/kern/subr_taskqueue.c

   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/cpuset.h>
  34 #include <sys/interrupt.h>
  35 #include <sys/kernel.h>
  36 #include <sys/kthread.h>
  37 #include <sys/limits.h>
  38 #include <sys/lock.h>
  39 #include <sys/malloc.h>
  40 #include <sys/mutex.h>
  41 #include <sys/proc.h>
  42 #include <sys/sched.h>
  43 #include <sys/taskqueue.h>
  44 #include <sys/unistd.h>
  45 #include <machine/stdarg.h>
  46
  47 static MALLOC_DEFINE(M_TASKQUEUE, "taskqueue", "Task Queues");
  48 static void     *taskqueue_giant_ih;
  49 static void     *taskqueue_ih;
  50 static void      taskqueue_fast_enqueue(void *);
  51 static void      taskqueue_swi_enqueue(void *);
  52 static void      taskqueue_swi_giant_enqueue(void *);
  53
  54 struct taskqueue_busy {
  55         struct task     *tb_running;
  56         TAILQ_ENTRY(taskqueue_busy) tb_link;
  57 };
  58
  59 struct task * const TB_DRAIN_WAITER = (struct task *)0x1;
  60
  61 struct taskqueue {
  62         STAILQ_HEAD(, task)     tq_queue;
  63         taskqueue_enqueue_fn    tq_enqueue;
  64         void                    *tq_context;
  65         TAILQ_HEAD(, taskqueue_busy) tq_active;
  66         struct mtx              tq_mutex;
  67         struct thread           **tq_threads;
  68         int                     tq_tcount;
  69         int                     tq_spin;
  70         int                     tq_flags;
  71         int                     tq_callouts;
  72         taskqueue_callback_fn   tq_callbacks[TASKQUEUE_NUM_CALLBACKS];
  73         void                    *tq_cb_contexts[TASKQUEUE_NUM_CALLBACKS];
  74 };
  75
  76 #define TQ_FLAGS_ACTIVE         (1 << 0)
  77 #define TQ_FLAGS_BLOCKED        (1 << 1)
  78 #define TQ_FLAGS_UNLOCKED_ENQUEUE       (1 << 2)
  79
  80 #define DT_CALLOUT_ARMED        (1 << 0)
  81
  82 #define TQ_LOCK(tq)                                                     \
  83         do {                                                            \
  84                 if ((tq)->tq_spin)                                      \
  85                         mtx_lock_spin(&(tq)->tq_mutex);                 \
  86                 else                                                    \
  87                         mtx_lock(&(tq)->tq_mutex);                      \
  88         } while (0)
  89 #define TQ_ASSERT_LOCKED(tq)    mtx_assert(&(tq)->tq_mutex, MA_OWNED)
  90
  91 #define TQ_UNLOCK(tq)                                                   \
  92         do {                                                            \
  93                 if ((tq)->tq_spin)                                      \
  94                         mtx_unlock_spin(&(tq)->tq_mutex);               \
  95                 else                                                    \
  96                         mtx_unlock(&(tq)->tq_mutex);                    \
  97         } while (0)
  98 #define TQ_ASSERT_UNLOCKED(tq)  mtx_assert(&(tq)->tq_mutex, MA_NOTOWNED)
  99
 100 void
 101 _timeout_task_init(struct taskqueue *queue, struct timeout_task *timeout_task,
 102     int priority, task_fn_t func, void *context)
 103 {
 104
 105         TASK_INIT(&timeout_task->t, priority, func, context);
 106         callout_init_mtx(&timeout_task->c, &queue->tq_mutex,
 107             CALLOUT_RETURNUNLOCKED);
 108         timeout_task->q = queue;
 109         timeout_task->f = 0;
 110 }
 111
 112 static __inline int
 113 TQ_SLEEP(struct taskqueue *tq, void *p, struct mtx *m, int pri, const char *wm,
 114     int t)
 115 {
 116         if (tq->tq_spin)
 117                 return (msleep_spin(p, m, wm, t));
 118         return (msleep(p, m, pri, wm, t));
 119 }
 120
 121 static struct taskqueue *
 122 _taskqueue_create(const char *name __unused, int mflags,
 123                  taskqueue_enqueue_fn enqueue, void *context,
 124                  int mtxflags, const char *mtxname)
 125 {
 126         struct taskqueue *queue;
 127
 128         queue = malloc(sizeof(struct taskqueue), M_TASKQUEUE, mflags | M_ZERO);
 129         if (!queue)
 130                 return NULL;
 131
 132         STAILQ_INIT(&queue->tq_queue);
 133         TAILQ_INIT(&queue->tq_active);
 134         queue->tq_enqueue = enqueue;
 135         queue->tq_context = context;
 136         queue->tq_spin = (mtxflags & MTX_SPIN) != 0;
 137         queue->tq_flags |= TQ_FLAGS_ACTIVE;
 138         if (enqueue == taskqueue_fast_enqueue ||
 139             enqueue == taskqueue_swi_enqueue ||
 140             enqueue == taskqueue_swi_giant_enqueue ||
 141             enqueue == taskqueue_thread_enqueue)
 142                 queue->tq_flags |= TQ_FLAGS_UNLOCKED_ENQUEUE;
 143         mtx_init(&queue->tq_mutex, mtxname, NULL, mtxflags);
 144
 145         return queue;
 146 }
 147
 148 struct taskqueue *
 149 taskqueue_create(const char *name, int mflags,
 150                  taskqueue_enqueue_fn enqueue, void *context)
 151 {
 152         return _taskqueue_create(name, mflags, enqueue, context,
 153                         MTX_DEF, "taskqueue");
 154 }
 155
 156 void
 157 taskqueue_set_callback(struct taskqueue *queue,
 158     enum taskqueue_callback_type cb_type, taskqueue_callback_fn callback,
 159     void *context)
 160 {
 161
 162         KASSERT(((cb_type >= TASKQUEUE_CALLBACK_TYPE_MIN) &&
 163             (cb_type <= TASKQUEUE_CALLBACK_TYPE_MAX)),
 164             ("Callback type %d not valid, must be %d-%d", cb_type,
 165             TASKQUEUE_CALLBACK_TYPE_MIN, TASKQUEUE_CALLBACK_TYPE_MAX));
 166         KASSERT((queue->tq_callbacks[cb_type] == NULL),
 167             ("Re-initialization of taskqueue callback?"));
 168
 169         queue->tq_callbacks[cb_type] = callback;
 170         queue->tq_cb_contexts[cb_type] = context;
 171 }
 172
 173 /*
 174  * Signal a taskqueue thread to terminate.
 175  */
 176 static void
 177 taskqueue_terminate(struct thread **pp, struct taskqueue *tq)
 178 {
 179
 180         while (tq->tq_tcount > 0 || tq->tq_callouts > 0) {
 181                 wakeup(tq);
 182                 TQ_SLEEP(tq, pp, &tq->tq_mutex, PWAIT, "taskqueue_destroy", 0);
 183         }
 184 }
 185
 186 void
 187 taskqueue_free(struct taskqueue *queue)
 188 {
 189
 190         TQ_LOCK(queue);
 191         queue->tq_flags &= ~TQ_FLAGS_ACTIVE;
 192         taskqueue_terminate(queue->tq_threads, queue);
 193         KASSERT(TAILQ_EMPTY(&queue->tq_active), ("Tasks still running?"));
 194         KASSERT(queue->tq_callouts == 0, ("Armed timeout tasks"));
 195         mtx_destroy(&queue->tq_mutex);
 196         free(queue->tq_threads, M_TASKQUEUE);
 197         free(queue, M_TASKQUEUE);
 198 }
 199
 200 static int
 201 taskqueue_enqueue_locked(struct taskqueue *queue, struct task *task)
 202 {
 203         struct task *ins;
 204         struct task *prev;
 205
 206         /*
 207          * Count multiple enqueues.
 208          */
 209         if (task->ta_pending) {
 210                 if (task->ta_pending < USHRT_MAX)
 211                         task->ta_pending++;
 212                 TQ_UNLOCK(queue);
 213                 return (0);
 214         }
 215
 216         /*
 217          * Optimise the case when all tasks have the same priority.
 218          */
 219         prev = STAILQ_LAST(&queue->tq_queue, task, ta_link);
 220         if (!prev || prev->ta_priority >= task->ta_priority) {
 221                 STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link);
 222         } else {
 223                 prev = NULL;
 224                 for (ins = STAILQ_FIRST(&queue->tq_queue); ins;
 225                      prev = ins, ins = STAILQ_NEXT(ins, ta_link))
 226                         if (ins->ta_priority < task->ta_priority)
 227                                 break;
 228
 229                 if (prev)
 230                         STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link);
 231                 else
 232                         STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link);
 233         }
 234
 235         task->ta_pending = 1;
 236         if ((queue->tq_flags & TQ_FLAGS_UNLOCKED_ENQUEUE) != 0)
 237                 TQ_UNLOCK(queue);
 238         if ((queue->tq_flags & TQ_FLAGS_BLOCKED) == 0)
 239                 queue->tq_enqueue(queue->tq_context);
 240         if ((queue->tq_flags & TQ_FLAGS_UNLOCKED_ENQUEUE) == 0)
 241                 TQ_UNLOCK(queue);
 242
 243         /* Return with lock released. */
 244         return (0);
 245 }
 246
 247 int
 248 taskqueue_enqueue(struct taskqueue *queue, struct task *task)
 249 {
 250         int res;
 251
 252         TQ_LOCK(queue);
 253         res = taskqueue_enqueue_locked(queue, task);
 254         /* The lock is released inside. */
 255
 256         return (res);
 257 }
 258
 259 static void
 260 taskqueue_timeout_func(void *arg)
 261 {
 262         struct taskqueue *queue;
 263         struct timeout_task *timeout_task;
 264
 265         timeout_task = arg;
 266         queue = timeout_task->q;
 267         KASSERT((timeout_task->f & DT_CALLOUT_ARMED) != 0, ("Stray timeout"));
 268         timeout_task->f &= ~DT_CALLOUT_ARMED;
 269         queue->tq_callouts--;
 270         taskqueue_enqueue_locked(timeout_task->q, &timeout_task->t);
 271         /* The lock is released inside. */
 272 }
 273
 274 int
 275 taskqueue_enqueue_timeout(struct taskqueue *queue,
 276     struct timeout_task *timeout_task, int ticks)
 277 {
 278         int res;
 279
 280         TQ_LOCK(queue);
 281         KASSERT(timeout_task->q == NULL || timeout_task->q == queue,
 282             ("Migrated queue"));
 283         KASSERT(!queue->tq_spin, ("Timeout for spin-queue"));
 284         timeout_task->q = queue;
 285         res = timeout_task->t.ta_pending;
 286         if (ticks == 0) {
 287                 taskqueue_enqueue_locked(queue, &timeout_task->t);
 288                 /* The lock is released inside. */
 289         } else {
 290                 if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
 291                         res++;
 292                 } else {
 293                         queue->tq_callouts++;
 294                         timeout_task->f |= DT_CALLOUT_ARMED;
 295                         if (ticks < 0)
 296                                 ticks = -ticks; /* Ignore overflow. */
 297                 }
 298                 if (ticks > 0) {
 299                         callout_reset(&timeout_task->c, ticks,
 300                             taskqueue_timeout_func, timeout_task);
 301                 }
 302                 TQ_UNLOCK(queue);
 303         }
 304         return (res);
 305 }
 306
 307 static void
 308 taskqueue_task_nop_fn(void *context, int pending)
 309 {
 310 }
 311
 312 /*
 313  * Block until all currently queued tasks in this taskqueue
 314  * have begun execution.  Tasks queued during execution of
 315  * this function are ignored.
 316  */
 317 static void
 318 taskqueue_drain_tq_queue(struct taskqueue *queue)
 319 {
 320         struct task t_barrier;
 321
 322         if (STAILQ_EMPTY(&queue->tq_queue))
 323                 return;
 324
 325         /*
 326          * Enqueue our barrier with the lowest possible priority
 327          * so we are inserted after all current tasks.
 328          */
 329         TASK_INIT(&t_barrier, 0, taskqueue_task_nop_fn, &t_barrier);
 330         taskqueue_enqueue_locked(queue, &t_barrier);
 331
 332         /*
 333          * Raise the barrier's priority so newly queued tasks cannot
 334          * pass it.
 335          */
 336         t_barrier.ta_priority = USHRT_MAX;
 337
 338         /*
 339          * Once the barrier has executed, all previously queued tasks
 340          * have completed or are currently executing.
 341          */
 342         while (t_barrier.ta_pending != 0)
 343                 TQ_SLEEP(queue, &t_barrier, &queue->tq_mutex, PWAIT, "-", 0);
 344 }
 345
 346 /*
 347  * Block until all currently executing tasks for this taskqueue
 348  * complete.  Tasks that begin execution during the execution
 349  * of this function are ignored.
 350  */
 351 static void
 352 taskqueue_drain_tq_active(struct taskqueue *queue)
 353 {
 354         struct taskqueue_busy tb_marker, *tb_first;
 355
 356         if (TAILQ_EMPTY(&queue->tq_active))
 357                 return;
 358
 359         /* Block taskq_terminate().*/
 360         queue->tq_callouts++;
 361
 362         /*
 363          * Wait for all currently executing taskqueue threads
 364          * to go idle.
 365          */
 366         tb_marker.tb_running = TB_DRAIN_WAITER;
 367         TAILQ_INSERT_TAIL(&queue->tq_active, &tb_marker, tb_link);
 368         while (TAILQ_FIRST(&queue->tq_active) != &tb_marker)
 369                 TQ_SLEEP(queue, &tb_marker, &queue->tq_mutex, PWAIT, "-", 0);
 370         TAILQ_REMOVE(&queue->tq_active, &tb_marker, tb_link);
 371
 372         /*
 373          * Wakeup any other drain waiter that happened to queue up
 374          * without any intervening active thread.
 375          */
 376         tb_first = TAILQ_FIRST(&queue->tq_active);
 377         if (tb_first != NULL && tb_first->tb_running == TB_DRAIN_WAITER)
 378                 wakeup(tb_first);
 379
 380         /* Release taskqueue_terminate(). */
 381         queue->tq_callouts--;
 382         if ((queue->tq_flags & TQ_FLAGS_ACTIVE) == 0)
 383                 wakeup_one(queue->tq_threads);
 384 }
 385
 386 void
 387 taskqueue_block(struct taskqueue *queue)
 388 {
 389
 390         TQ_LOCK(queue);
 391         queue->tq_flags |= TQ_FLAGS_BLOCKED;
 392         TQ_UNLOCK(queue);
 393 }
 394
 395 void
 396 taskqueue_unblock(struct taskqueue *queue)
 397 {
 398
 399         TQ_LOCK(queue);
 400         queue->tq_flags &= ~TQ_FLAGS_BLOCKED;
 401         if (!STAILQ_EMPTY(&queue->tq_queue))
 402                 queue->tq_enqueue(queue->tq_context);
 403         TQ_UNLOCK(queue);
 404 }
 405
 406 static void
 407 taskqueue_run_locked(struct taskqueue *queue)
 408 {
 409         struct taskqueue_busy tb;
 410         struct taskqueue_busy *tb_first;
 411         struct task *task;
 412         int pending;
 413
 414         TQ_ASSERT_LOCKED(queue);
 415         tb.tb_running = NULL;
 416
 417         while (STAILQ_FIRST(&queue->tq_queue)) {
 418                 TAILQ_INSERT_TAIL(&queue->tq_active, &tb, tb_link);
 419
 420                 /*
 421                  * Carefully remove the first task from the queue and
 422                  * zero its pending count.
 423                  */
 424                 task = STAILQ_FIRST(&queue->tq_queue);
 425                 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link);
 426                 pending = task->ta_pending;
 427                 task->ta_pending = 0;
 428                 tb.tb_running = task;
 429                 TQ_UNLOCK(queue);
 430
 431                 task->ta_func(task->ta_context, pending);
 432
 433                 TQ_LOCK(queue);
 434                 tb.tb_running = NULL;
 435                 wakeup(task);
 436
 437                 TAILQ_REMOVE(&queue->tq_active, &tb, tb_link);
 438                 tb_first = TAILQ_FIRST(&queue->tq_active);
 439                 if (tb_first != NULL &&
 440                     tb_first->tb_running == TB_DRAIN_WAITER)
 441                         wakeup(tb_first);
 442         }
 443 }
 444
 445 void
 446 taskqueue_run(struct taskqueue *queue)
 447 {
 448
 449         TQ_LOCK(queue);
 450         taskqueue_run_locked(queue);
 451         TQ_UNLOCK(queue);
 452 }
 453
 454 static int
 455 task_is_running(struct taskqueue *queue, struct task *task)
 456 {
 457         struct taskqueue_busy *tb;
 458
 459         TQ_ASSERT_LOCKED(queue);
 460         TAILQ_FOREACH(tb, &queue->tq_active, tb_link) {
 461                 if (tb->tb_running == task)
 462                         return (1);
 463         }
 464         return (0);
 465 }
 466
 467 static int
 468 taskqueue_cancel_locked(struct taskqueue *queue, struct task *task,
 469     u_int *pendp)
 470 {
 471
 472         if (task->ta_pending > 0)
 473                 STAILQ_REMOVE(&queue->tq_queue, task, task, ta_link);
 474         if (pendp != NULL)
 475                 *pendp = task->ta_pending;
 476         task->ta_pending = 0;
 477         return (task_is_running(queue, task) ? EBUSY : 0);
 478 }
 479
 480 int
 481 taskqueue_cancel(struct taskqueue *queue, struct task *task, u_int *pendp)
 482 {
 483         int error;
 484
 485         TQ_LOCK(queue);
 486         error = taskqueue_cancel_locked(queue, task, pendp);
 487         TQ_UNLOCK(queue);
 488
 489         return (error);
 490 }
 491
 492 int
 493 taskqueue_cancel_timeout(struct taskqueue *queue,
 494     struct timeout_task *timeout_task, u_int *pendp)
 495 {
 496         u_int pending, pending1;
 497         int error;
 498
 499         TQ_LOCK(queue);
 500         pending = !!callout_stop(&timeout_task->c);
 501         error = taskqueue_cancel_locked(queue, &timeout_task->t, &pending1);
 502         if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
 503                 timeout_task->f &= ~DT_CALLOUT_ARMED;
 504                 queue->tq_callouts--;
 505         }
 506         TQ_UNLOCK(queue);
 507
 508         if (pendp != NULL)
 509                 *pendp = pending + pending1;
 510         return (error);
 511 }
 512
 513 void
 514 taskqueue_drain(struct taskqueue *queue, struct task *task)
 515 {
 516
 517         if (!queue->tq_spin)
 518                 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
 519
 520         TQ_LOCK(queue);
 521         while (task->ta_pending != 0 || task_is_running(queue, task))
 522                 TQ_SLEEP(queue, task, &queue->tq_mutex, PWAIT, "-", 0);
 523         TQ_UNLOCK(queue);
 524 }
 525
 526 void
 527 taskqueue_drain_all(struct taskqueue *queue)
 528 {
 529
 530         if (!queue->tq_spin)
 531                 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
 532
 533         TQ_LOCK(queue);
 534         taskqueue_drain_tq_queue(queue);
 535         taskqueue_drain_tq_active(queue);
 536         TQ_UNLOCK(queue);
 537 }
 538
 539 void
 540 taskqueue_drain_timeout(struct taskqueue *queue,
 541     struct timeout_task *timeout_task)
 542 {
 543
 544         callout_drain(&timeout_task->c);
 545         taskqueue_drain(queue, &timeout_task->t);
 546 }
 547
 548 static void
 549 taskqueue_swi_enqueue(void *context)
 550 {
 551         swi_sched(taskqueue_ih, 0);
 552 }
 553
 554 static void
 555 taskqueue_swi_run(void *dummy)
 556 {
 557         taskqueue_run(taskqueue_swi);
 558 }
 559
 560 static void
 561 taskqueue_swi_giant_enqueue(void *context)
 562 {
 563         swi_sched(taskqueue_giant_ih, 0);
 564 }
 565
 566 static void
 567 taskqueue_swi_giant_run(void *dummy)
 568 {
 569         taskqueue_run(taskqueue_swi_giant);
 570 }
 571
 572 static int
 573 _taskqueue_start_threads(struct taskqueue **tqp, int count, int pri,
 574     cpuset_t *mask, const char *name, va_list ap)
 575 {
 576         char ktname[MAXCOMLEN + 1];
 577         struct thread *td;
 578         struct taskqueue *tq;
 579         int i, error;
 580
 581         if (count <= 0)
 582                 return (EINVAL);
 583
 584         vsnprintf(ktname, sizeof(ktname), name, ap);
 585         tq = *tqp;
 586
 587         tq->tq_threads = malloc(sizeof(struct thread *) * count, M_TASKQUEUE,
 588             M_NOWAIT | M_ZERO);
 589         if (tq->tq_threads == NULL) {
 590                 printf("%s: no memory for %s threads\n", __func__, ktname);
 591                 return (ENOMEM);
 592         }
 593
 594         for (i = 0; i < count; i++) {
 595                 if (count == 1)
 596                         error = kthread_add(taskqueue_thread_loop, tqp, NULL,
 597                             &tq->tq_threads[i], RFSTOPPED, 0, "%s", ktname);
 598                 else
 599                         error = kthread_add(taskqueue_thread_loop, tqp, NULL,
 600                             &tq->tq_threads[i], RFSTOPPED, 0,
 601                             "%s_%d", ktname, i);
 602                 if (error) {
 603                         /* should be ok to continue, taskqueue_free will dtrt */
 604                         printf("%s: kthread_add(%s): error %d", __func__,
 605                             ktname, error);
 606                         tq->tq_threads[i] = NULL;               /* paranoid */
 607                 } else
 608                         tq->tq_tcount++;
 609         }
 610         for (i = 0; i < count; i++) {
 611                 if (tq->tq_threads[i] == NULL)
 612                         continue;
 613                 td = tq->tq_threads[i];
 614                 if (mask) {
 615                         error = cpuset_setthread(td->td_tid, mask);
 616                         /*
 617                          * Failing to pin is rarely an actual fatal error;
 618                          * it'll just affect performance.
 619                          */
 620                         if (error)
 621                                 printf("%s: curthread=%llu: can't pin; "
 622                                     "error=%d\n",
 623                                     __func__,
 624                                     (unsigned long long) td->td_tid,
 625                                     error);
 626                 }
 627                 thread_lock(td);
 628                 sched_prio(td, pri);
 629                 sched_add(td, SRQ_BORING);
 630                 thread_unlock(td);
 631         }
 632
 633         return (0);
 634 }
 635
 636 int
 637 taskqueue_start_threads(struct taskqueue **tqp, int count, int pri,
 638     const char *name, ...)
 639 {
 640         va_list ap;
 641         int error;
 642
 643         va_start(ap, name);
 644         error = _taskqueue_start_threads(tqp, count, pri, NULL, name, ap);
 645         va_end(ap);
 646         return (error);
 647 }
 648
 649 int
 650 taskqueue_start_threads_cpuset(struct taskqueue **tqp, int count, int pri,
 651     cpuset_t *mask, const char *name, ...)
 652 {
 653         va_list ap;
 654         int error;
 655
 656         va_start(ap, name);
 657         error = _taskqueue_start_threads(tqp, count, pri, mask, name, ap);
 658         va_end(ap);
 659         return (error);
 660 }
 661
 662 int
 663 taskqueue_start_threads_pinned(struct taskqueue **tqp, int count, int pri,
 664     int cpu_id, const char *name, ...)
 665 {
 666         cpuset_t mask;
 667         va_list ap;
 668         int error;
 669
 670         /*
 671          * In case someone passes in NOCPU, just fall back to the
 672          * default behaviour of "don't pin".
 673          */
 674         if (cpu_id != NOCPU) {
 675                 CPU_ZERO(&mask);
 676                 CPU_SET(cpu_id, &mask);
 677         }
 678
 679         va_start(ap, name);
 680         error = _taskqueue_start_threads(tqp, count, pri,
 681             cpu_id == NOCPU ? NULL : &mask, name, ap);
 682         va_end(ap);
 683         return (error);
 684 }
 685
 686 static inline void
 687 taskqueue_run_callback(struct taskqueue *tq,
 688     enum taskqueue_callback_type cb_type)
 689 {
 690         taskqueue_callback_fn tq_callback;
 691
 692         TQ_ASSERT_UNLOCKED(tq);
 693         tq_callback = tq->tq_callbacks[cb_type];
 694         if (tq_callback != NULL)
 695                 tq_callback(tq->tq_cb_contexts[cb_type]);
 696 }
 697
 698 void
 699 taskqueue_thread_loop(void *arg)
 700 {
 701         struct taskqueue **tqp, *tq;
 702
 703         tqp = arg;
 704         tq = *tqp;
 705         taskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_INIT);
 706         TQ_LOCK(tq);
 707         while ((tq->tq_flags & TQ_FLAGS_ACTIVE) != 0) {
 708                 taskqueue_run_locked(tq);
 709                 /*
 710                  * Because taskqueue_run() can drop tq_mutex, we need to
 711                  * check if the TQ_FLAGS_ACTIVE flag wasn't removed in the
 712                  * meantime, which means we missed a wakeup.
 713                  */
 714                 if ((tq->tq_flags & TQ_FLAGS_ACTIVE) == 0)
 715                         break;
 716                 TQ_SLEEP(tq, tq, &tq->tq_mutex, 0, "-", 0);
 717         }
 718         taskqueue_run_locked(tq);
 719
 720         /*
 721          * This thread is on its way out, so just drop the lock temporarily
 722          * in order to call the shutdown callback.  This allows the callback
 723          * to look at the taskqueue, even just before it dies.
 724          */
 725         TQ_UNLOCK(tq);
 726         taskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_SHUTDOWN);
 727         TQ_LOCK(tq);
 728
 729         /* rendezvous with thread that asked us to terminate */
 730         tq->tq_tcount--;
 731         wakeup_one(tq->tq_threads);
 732         TQ_UNLOCK(tq);
 733         kthread_exit();
 734 }
 735
 736 void
 737 taskqueue_thread_enqueue(void *context)
 738 {
 739         struct taskqueue **tqp, *tq;
 740
 741         tqp = context;
 742         tq = *tqp;
 743
 744         wakeup_one(tq);
 745 }
 746
 747 TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, NULL,
 748                  swi_add(NULL, "task queue", taskqueue_swi_run, NULL, SWI_TQ,
 749                      INTR_MPSAFE, &taskqueue_ih));
 750
 751 TASKQUEUE_DEFINE(swi_giant, taskqueue_swi_giant_enqueue, NULL,
 752                  swi_add(NULL, "Giant taskq", taskqueue_swi_giant_run,
 753                      NULL, SWI_TQ_GIANT, 0, &taskqueue_giant_ih));
 754
 755 TASKQUEUE_DEFINE_THREAD(thread);
 756
 757 struct taskqueue *
 758 taskqueue_create_fast(const char *name, int mflags,
 759                  taskqueue_enqueue_fn enqueue, void *context)
 760 {
 761         return _taskqueue_create(name, mflags, enqueue, context,
 762                         MTX_SPIN, "fast_taskqueue");
 763 }
 764
 765 /* NB: for backwards compatibility */
 766 int
 767 taskqueue_enqueue_fast(struct taskqueue *queue, struct task *task)
 768 {
 769         return taskqueue_enqueue(queue, task);
 770 }
 771
 772 static void     *taskqueue_fast_ih;
 773
 774 static void
 775 taskqueue_fast_enqueue(void *context)
 776 {
 777         swi_sched(taskqueue_fast_ih, 0);
 778 }
 779
 780 static void
 781 taskqueue_fast_run(void *dummy)
 782 {
 783         taskqueue_run(taskqueue_fast);
 784 }
 785
 786 TASKQUEUE_FAST_DEFINE(fast, taskqueue_fast_enqueue, NULL,
 787         swi_add(NULL, "fast taskq", taskqueue_fast_run, NULL,
 788         SWI_TQ_FAST, INTR_MPSAFE, &taskqueue_fast_ih));
 789
 790 int
 791 taskqueue_member(struct taskqueue *queue, struct thread *td)
 792 {
 793         int i, j, ret = 0;
 794
 795         for (i = 0, j = 0; ; i++) {
 796                 if (queue->tq_threads[i] == NULL)
 797                         continue;
 798                 if (queue->tq_threads[i] == td) {
 799                         ret = 1;
 800                         break;
 801                 }
 802                 if (++j >= queue->tq_tcount)
 803                         break;
 804         }
 805         return (ret);
 806 }