sys/kern/subr_taskqueue.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
   3  *
   4  * Copyright (c) 2000 Doug Rabson
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  */
  28
  29 #include <sys/cdefs.h>
  30 __FBSDID("$FreeBSD$");
  31
  32 #include <sys/param.h>
  33 #include <sys/systm.h>
  34 #include <sys/bus.h>
  35 #include <sys/cpuset.h>
  36 #include <sys/interrupt.h>
  37 #include <sys/kernel.h>
  38 #include <sys/kthread.h>
  39 #include <sys/libkern.h>
  40 #include <sys/limits.h>
  41 #include <sys/lock.h>
  42 #include <sys/malloc.h>
  43 #include <sys/mutex.h>
  44 #include <sys/proc.h>
  45 #include <sys/sched.h>
  46 #include <sys/smp.h>
  47 #include <sys/taskqueue.h>
  48 #include <sys/unistd.h>
  49 #include <machine/stdarg.h>
  50
  51 static MALLOC_DEFINE(M_TASKQUEUE, "taskqueue", "Task Queues");
  52 static void     *taskqueue_giant_ih;
  53 static void     *taskqueue_ih;
  54 static void      taskqueue_fast_enqueue(void *);
  55 static void      taskqueue_swi_enqueue(void *);
  56 static void      taskqueue_swi_giant_enqueue(void *);
  57
  58 struct taskqueue_busy {
  59         struct task     *tb_running;
  60         TAILQ_ENTRY(taskqueue_busy) tb_link;
  61 };
  62
  63 struct task * const TB_DRAIN_WAITER = (struct task *)0x1;
  64
  65 struct taskqueue {
  66         STAILQ_HEAD(, task)     tq_queue;
  67         taskqueue_enqueue_fn    tq_enqueue;
  68         void                    *tq_context;
  69         char                    *tq_name;
  70         TAILQ_HEAD(, taskqueue_busy) tq_active;
  71         struct mtx              tq_mutex;
  72         struct thread           **tq_threads;
  73         int                     tq_tcount;
  74         int                     tq_spin;
  75         int                     tq_flags;
  76         int                     tq_callouts;
  77         taskqueue_callback_fn   tq_callbacks[TASKQUEUE_NUM_CALLBACKS];
  78         void                    *tq_cb_contexts[TASKQUEUE_NUM_CALLBACKS];
  79 };
  80
  81 #define TQ_FLAGS_ACTIVE         (1 << 0)
  82 #define TQ_FLAGS_BLOCKED        (1 << 1)
  83 #define TQ_FLAGS_UNLOCKED_ENQUEUE       (1 << 2)
  84
  85 #define DT_CALLOUT_ARMED        (1 << 0)
  86 #define DT_DRAIN_IN_PROGRESS    (1 << 1)
  87
  88 #define TQ_LOCK(tq)                                                     \
  89         do {                                                            \
  90                 if ((tq)->tq_spin)                                      \
  91                         mtx_lock_spin(&(tq)->tq_mutex);                 \
  92                 else                                                    \
  93                         mtx_lock(&(tq)->tq_mutex);                      \
  94         } while (0)
  95 #define TQ_ASSERT_LOCKED(tq)    mtx_assert(&(tq)->tq_mutex, MA_OWNED)
  96
  97 #define TQ_UNLOCK(tq)                                                   \
  98         do {                                                            \
  99                 if ((tq)->tq_spin)                                      \
 100                         mtx_unlock_spin(&(tq)->tq_mutex);               \
 101                 else                                                    \
 102                         mtx_unlock(&(tq)->tq_mutex);                    \
 103         } while (0)
 104 #define TQ_ASSERT_UNLOCKED(tq)  mtx_assert(&(tq)->tq_mutex, MA_NOTOWNED)
 105
 106 void
 107 _timeout_task_init(struct taskqueue *queue, struct timeout_task *timeout_task,
 108     int priority, task_fn_t func, void *context)
 109 {
 110
 111         TASK_INIT(&timeout_task->t, priority, func, context);
 112         callout_init_mtx(&timeout_task->c, &queue->tq_mutex,
 113             CALLOUT_RETURNUNLOCKED);
 114         timeout_task->q = queue;
 115         timeout_task->f = 0;
 116 }
 117
 118 static __inline int
 119 TQ_SLEEP(struct taskqueue *tq, void *p, struct mtx *m, int pri, const char *wm,
 120     int t)
 121 {
 122         if (tq->tq_spin)
 123                 return (msleep_spin(p, m, wm, t));
 124         return (msleep(p, m, pri, wm, t));
 125 }
 126
 127 static struct taskqueue *
 128 _taskqueue_create(const char *name, int mflags,
 129                  taskqueue_enqueue_fn enqueue, void *context,
 130                  int mtxflags, const char *mtxname __unused)
 131 {
 132         struct taskqueue *queue;
 133         char *tq_name;
 134
 135         tq_name = malloc(TASKQUEUE_NAMELEN, M_TASKQUEUE, mflags | M_ZERO);
 136         if (tq_name == NULL)
 137                 return (NULL);
 138
 139         queue = malloc(sizeof(struct taskqueue), M_TASKQUEUE, mflags | M_ZERO);
 140         if (queue == NULL) {
 141                 free(tq_name, M_TASKQUEUE);
 142                 return (NULL);
 143         }
 144
 145         snprintf(tq_name, TASKQUEUE_NAMELEN, "%s", (name) ? name : "taskqueue");
 146
 147         STAILQ_INIT(&queue->tq_queue);
 148         TAILQ_INIT(&queue->tq_active);
 149         queue->tq_enqueue = enqueue;
 150         queue->tq_context = context;
 151         queue->tq_name = tq_name;
 152         queue->tq_spin = (mtxflags & MTX_SPIN) != 0;
 153         queue->tq_flags |= TQ_FLAGS_ACTIVE;
 154         if (enqueue == taskqueue_fast_enqueue ||
 155             enqueue == taskqueue_swi_enqueue ||
 156             enqueue == taskqueue_swi_giant_enqueue ||
 157             enqueue == taskqueue_thread_enqueue)
 158                 queue->tq_flags |= TQ_FLAGS_UNLOCKED_ENQUEUE;
 159         mtx_init(&queue->tq_mutex, tq_name, NULL, mtxflags);
 160
 161         return (queue);
 162 }
 163
 164 struct taskqueue *
 165 taskqueue_create(const char *name, int mflags,
 166                  taskqueue_enqueue_fn enqueue, void *context)
 167 {
 168
 169         return _taskqueue_create(name, mflags, enqueue, context,
 170                         MTX_DEF, name);
 171 }
 172
 173 void
 174 taskqueue_set_callback(struct taskqueue *queue,
 175     enum taskqueue_callback_type cb_type, taskqueue_callback_fn callback,
 176     void *context)
 177 {
 178
 179         KASSERT(((cb_type >= TASKQUEUE_CALLBACK_TYPE_MIN) &&
 180             (cb_type <= TASKQUEUE_CALLBACK_TYPE_MAX)),
 181             ("Callback type %d not valid, must be %d-%d", cb_type,
 182             TASKQUEUE_CALLBACK_TYPE_MIN, TASKQUEUE_CALLBACK_TYPE_MAX));
 183         KASSERT((queue->tq_callbacks[cb_type] == NULL),
 184             ("Re-initialization of taskqueue callback?"));
 185
 186         queue->tq_callbacks[cb_type] = callback;
 187         queue->tq_cb_contexts[cb_type] = context;
 188 }
 189
 190 /*
 191  * Signal a taskqueue thread to terminate.
 192  */
 193 static void
 194 taskqueue_terminate(struct thread **pp, struct taskqueue *tq)
 195 {
 196
 197         while (tq->tq_tcount > 0 || tq->tq_callouts > 0) {
 198                 wakeup(tq);
 199                 TQ_SLEEP(tq, pp, &tq->tq_mutex, PWAIT, "taskqueue_destroy", 0);
 200         }
 201 }
 202
 203 void
 204 taskqueue_free(struct taskqueue *queue)
 205 {
 206
 207         TQ_LOCK(queue);
 208         queue->tq_flags &= ~TQ_FLAGS_ACTIVE;
 209         taskqueue_terminate(queue->tq_threads, queue);
 210         KASSERT(TAILQ_EMPTY(&queue->tq_active), ("Tasks still running?"));
 211         KASSERT(queue->tq_callouts == 0, ("Armed timeout tasks"));
 212         mtx_destroy(&queue->tq_mutex);
 213         free(queue->tq_threads, M_TASKQUEUE);
 214         free(queue->tq_name, M_TASKQUEUE);
 215         free(queue, M_TASKQUEUE);
 216 }
 217
 218 static int
 219 taskqueue_enqueue_locked(struct taskqueue *queue, struct task *task)
 220 {
 221         struct task *ins;
 222         struct task *prev;
 223
 224         KASSERT(task->ta_func != NULL, ("enqueueing task with NULL func"));
 225         /*
 226          * Count multiple enqueues.
 227          */
 228         if (task->ta_pending) {
 229                 if (task->ta_pending < USHRT_MAX)
 230                         task->ta_pending++;
 231                 TQ_UNLOCK(queue);
 232                 return (0);
 233         }
 234
 235         /*
 236          * Optimise the case when all tasks have the same priority.
 237          */
 238         prev = STAILQ_LAST(&queue->tq_queue, task, ta_link);
 239         if (!prev || prev->ta_priority >= task->ta_priority) {
 240                 STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link);
 241         } else {
 242                 prev = NULL;
 243                 for (ins = STAILQ_FIRST(&queue->tq_queue); ins;
 244                      prev = ins, ins = STAILQ_NEXT(ins, ta_link))
 245                         if (ins->ta_priority < task->ta_priority)
 246                                 break;
 247
 248                 if (prev)
 249                         STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link);
 250                 else
 251                         STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link);
 252         }
 253
 254         task->ta_pending = 1;
 255         if ((queue->tq_flags & TQ_FLAGS_UNLOCKED_ENQUEUE) != 0)
 256                 TQ_UNLOCK(queue);
 257         if ((queue->tq_flags & TQ_FLAGS_BLOCKED) == 0)
 258                 queue->tq_enqueue(queue->tq_context);
 259         if ((queue->tq_flags & TQ_FLAGS_UNLOCKED_ENQUEUE) == 0)
 260                 TQ_UNLOCK(queue);
 261
 262         /* Return with lock released. */
 263         return (0);
 264 }
 265
 266 int
 267 taskqueue_enqueue(struct taskqueue *queue, struct task *task)
 268 {
 269         int res;
 270
 271         TQ_LOCK(queue);
 272         res = taskqueue_enqueue_locked(queue, task);
 273         /* The lock is released inside. */
 274
 275         return (res);
 276 }
 277
 278 static void
 279 taskqueue_timeout_func(void *arg)
 280 {
 281         struct taskqueue *queue;
 282         struct timeout_task *timeout_task;
 283
 284         timeout_task = arg;
 285         queue = timeout_task->q;
 286         KASSERT((timeout_task->f & DT_CALLOUT_ARMED) != 0, ("Stray timeout"));
 287         timeout_task->f &= ~DT_CALLOUT_ARMED;
 288         queue->tq_callouts--;
 289         taskqueue_enqueue_locked(timeout_task->q, &timeout_task->t);
 290         /* The lock is released inside. */
 291 }
 292
 293 int
 294 taskqueue_enqueue_timeout_sbt(struct taskqueue *queue,
 295     struct timeout_task *timeout_task, sbintime_t sbt, sbintime_t pr, int flags)
 296 {
 297         int res;
 298
 299         TQ_LOCK(queue);
 300         KASSERT(timeout_task->q == NULL || timeout_task->q == queue,
 301             ("Migrated queue"));
 302         KASSERT(!queue->tq_spin, ("Timeout for spin-queue"));
 303         timeout_task->q = queue;
 304         res = timeout_task->t.ta_pending;
 305         if (timeout_task->f & DT_DRAIN_IN_PROGRESS) {
 306                 /* Do nothing */
 307                 TQ_UNLOCK(queue);
 308                 res = -1;
 309         } else if (sbt == 0) {
 310                 taskqueue_enqueue_locked(queue, &timeout_task->t);
 311                 /* The lock is released inside. */
 312         } else {
 313                 if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
 314                         res++;
 315                 } else {
 316                         queue->tq_callouts++;
 317                         timeout_task->f |= DT_CALLOUT_ARMED;
 318                         if (sbt < 0)
 319                                 sbt = -sbt; /* Ignore overflow. */
 320                 }
 321                 if (sbt > 0) {
 322                         callout_reset_sbt(&timeout_task->c, sbt, pr,
 323                             taskqueue_timeout_func, timeout_task, flags);
 324                 }
 325                 TQ_UNLOCK(queue);
 326         }
 327         return (res);
 328 }
 329
 330 int
 331 taskqueue_enqueue_timeout(struct taskqueue *queue,
 332     struct timeout_task *ttask, int ticks)
 333 {
 334
 335         return (taskqueue_enqueue_timeout_sbt(queue, ttask, ticks * tick_sbt,
 336             0, 0));
 337 }
 338
 339 static void
 340 taskqueue_task_nop_fn(void *context, int pending)
 341 {
 342 }
 343
 344 /*
 345  * Block until all currently queued tasks in this taskqueue
 346  * have begun execution.  Tasks queued during execution of
 347  * this function are ignored.
 348  */
 349 static void
 350 taskqueue_drain_tq_queue(struct taskqueue *queue)
 351 {
 352         struct task t_barrier;
 353
 354         if (STAILQ_EMPTY(&queue->tq_queue))
 355                 return;
 356
 357         /*
 358          * Enqueue our barrier after all current tasks, but with
 359          * the highest priority so that newly queued tasks cannot
 360          * pass it.  Because of the high priority, we can not use
 361          * taskqueue_enqueue_locked directly (which drops the lock
 362          * anyway) so just insert it at tail while we have the
 363          * queue lock.
 364          */
 365         TASK_INIT(&t_barrier, USHRT_MAX, taskqueue_task_nop_fn, &t_barrier);
 366         STAILQ_INSERT_TAIL(&queue->tq_queue, &t_barrier, ta_link);
 367         t_barrier.ta_pending = 1;
 368
 369         /*
 370          * Once the barrier has executed, all previously queued tasks
 371          * have completed or are currently executing.
 372          */
 373         while (t_barrier.ta_pending != 0)
 374                 TQ_SLEEP(queue, &t_barrier, &queue->tq_mutex, PWAIT, "-", 0);
 375 }
 376
 377 /*
 378  * Block until all currently executing tasks for this taskqueue
 379  * complete.  Tasks that begin execution during the execution
 380  * of this function are ignored.
 381  */
 382 static void
 383 taskqueue_drain_tq_active(struct taskqueue *queue)
 384 {
 385         struct taskqueue_busy tb_marker, *tb_first;
 386
 387         if (TAILQ_EMPTY(&queue->tq_active))
 388                 return;
 389
 390         /* Block taskq_terminate().*/
 391         queue->tq_callouts++;
 392
 393         /*
 394          * Wait for all currently executing taskqueue threads
 395          * to go idle.
 396          */
 397         tb_marker.tb_running = TB_DRAIN_WAITER;
 398         TAILQ_INSERT_TAIL(&queue->tq_active, &tb_marker, tb_link);
 399         while (TAILQ_FIRST(&queue->tq_active) != &tb_marker)
 400                 TQ_SLEEP(queue, &tb_marker, &queue->tq_mutex, PWAIT, "-", 0);
 401         TAILQ_REMOVE(&queue->tq_active, &tb_marker, tb_link);
 402
 403         /*
 404          * Wakeup any other drain waiter that happened to queue up
 405          * without any intervening active thread.
 406          */
 407         tb_first = TAILQ_FIRST(&queue->tq_active);
 408         if (tb_first != NULL && tb_first->tb_running == TB_DRAIN_WAITER)
 409                 wakeup(tb_first);
 410
 411         /* Release taskqueue_terminate(). */
 412         queue->tq_callouts--;
 413         if ((queue->tq_flags & TQ_FLAGS_ACTIVE) == 0)
 414                 wakeup_one(queue->tq_threads);
 415 }
 416
 417 void
 418 taskqueue_block(struct taskqueue *queue)
 419 {
 420
 421         TQ_LOCK(queue);
 422         queue->tq_flags |= TQ_FLAGS_BLOCKED;
 423         TQ_UNLOCK(queue);
 424 }
 425
 426 void
 427 taskqueue_unblock(struct taskqueue *queue)
 428 {
 429
 430         TQ_LOCK(queue);
 431         queue->tq_flags &= ~TQ_FLAGS_BLOCKED;
 432         if (!STAILQ_EMPTY(&queue->tq_queue))
 433                 queue->tq_enqueue(queue->tq_context);
 434         TQ_UNLOCK(queue);
 435 }
 436
 437 static void
 438 taskqueue_run_locked(struct taskqueue *queue)
 439 {
 440         struct taskqueue_busy tb;
 441         struct taskqueue_busy *tb_first;
 442         struct task *task;
 443         int pending;
 444
 445         KASSERT(queue != NULL, ("tq is NULL"));
 446         TQ_ASSERT_LOCKED(queue);
 447         tb.tb_running = NULL;
 448
 449         while (STAILQ_FIRST(&queue->tq_queue)) {
 450                 TAILQ_INSERT_TAIL(&queue->tq_active, &tb, tb_link);
 451
 452                 /*
 453                  * Carefully remove the first task from the queue and
 454                  * zero its pending count.
 455                  */
 456                 task = STAILQ_FIRST(&queue->tq_queue);
 457                 KASSERT(task != NULL, ("task is NULL"));
 458                 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link);
 459                 pending = task->ta_pending;
 460                 task->ta_pending = 0;
 461                 tb.tb_running = task;
 462                 TQ_UNLOCK(queue);
 463
 464                 KASSERT(task->ta_func != NULL, ("task->ta_func is NULL"));
 465                 task->ta_func(task->ta_context, pending);
 466
 467                 TQ_LOCK(queue);
 468                 tb.tb_running = NULL;
 469                 wakeup(task);
 470
 471                 TAILQ_REMOVE(&queue->tq_active, &tb, tb_link);
 472                 tb_first = TAILQ_FIRST(&queue->tq_active);
 473                 if (tb_first != NULL &&
 474                     tb_first->tb_running == TB_DRAIN_WAITER)
 475                         wakeup(tb_first);
 476         }
 477 }
 478
 479 void
 480 taskqueue_run(struct taskqueue *queue)
 481 {
 482
 483         TQ_LOCK(queue);
 484         taskqueue_run_locked(queue);
 485         TQ_UNLOCK(queue);
 486 }
 487
 488 static int
 489 task_is_running(struct taskqueue *queue, struct task *task)
 490 {
 491         struct taskqueue_busy *tb;
 492
 493         TQ_ASSERT_LOCKED(queue);
 494         TAILQ_FOREACH(tb, &queue->tq_active, tb_link) {
 495                 if (tb->tb_running == task)
 496                         return (1);
 497         }
 498         return (0);
 499 }
 500
 501 /*
 502  * Only use this function in single threaded contexts. It returns
 503  * non-zero if the given task is either pending or running. Else the
 504  * task is idle and can be queued again or freed.
 505  */
 506 int
 507 taskqueue_poll_is_busy(struct taskqueue *queue, struct task *task)
 508 {
 509         int retval;
 510
 511         TQ_LOCK(queue);
 512         retval = task->ta_pending > 0 || task_is_running(queue, task);
 513         TQ_UNLOCK(queue);
 514
 515         return (retval);
 516 }
 517
 518 static int
 519 taskqueue_cancel_locked(struct taskqueue *queue, struct task *task,
 520     u_int *pendp)
 521 {
 522
 523         if (task->ta_pending > 0)
 524                 STAILQ_REMOVE(&queue->tq_queue, task, task, ta_link);
 525         if (pendp != NULL)
 526                 *pendp = task->ta_pending;
 527         task->ta_pending = 0;
 528         return (task_is_running(queue, task) ? EBUSY : 0);
 529 }
 530
 531 int
 532 taskqueue_cancel(struct taskqueue *queue, struct task *task, u_int *pendp)
 533 {
 534         int error;
 535
 536         TQ_LOCK(queue);
 537         error = taskqueue_cancel_locked(queue, task, pendp);
 538         TQ_UNLOCK(queue);
 539
 540         return (error);
 541 }
 542
 543 int
 544 taskqueue_cancel_timeout(struct taskqueue *queue,
 545     struct timeout_task *timeout_task, u_int *pendp)
 546 {
 547         u_int pending, pending1;
 548         int error;
 549
 550         TQ_LOCK(queue);
 551         pending = !!(callout_stop(&timeout_task->c) > 0);
 552         error = taskqueue_cancel_locked(queue, &timeout_task->t, &pending1);
 553         if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
 554                 timeout_task->f &= ~DT_CALLOUT_ARMED;
 555                 queue->tq_callouts--;
 556         }
 557         TQ_UNLOCK(queue);
 558
 559         if (pendp != NULL)
 560                 *pendp = pending + pending1;
 561         return (error);
 562 }
 563
 564 void
 565 taskqueue_drain(struct taskqueue *queue, struct task *task)
 566 {
 567
 568         if (!queue->tq_spin)
 569                 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
 570
 571         TQ_LOCK(queue);
 572         while (task->ta_pending != 0 || task_is_running(queue, task))
 573                 TQ_SLEEP(queue, task, &queue->tq_mutex, PWAIT, "-", 0);
 574         TQ_UNLOCK(queue);
 575 }
 576
 577 void
 578 taskqueue_drain_all(struct taskqueue *queue)
 579 {
 580
 581         if (!queue->tq_spin)
 582                 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
 583
 584         TQ_LOCK(queue);
 585         taskqueue_drain_tq_queue(queue);
 586         taskqueue_drain_tq_active(queue);
 587         TQ_UNLOCK(queue);
 588 }
 589
 590 void
 591 taskqueue_drain_timeout(struct taskqueue *queue,
 592     struct timeout_task *timeout_task)
 593 {
 594
 595         /*
 596          * Set flag to prevent timer from re-starting during drain:
 597          */
 598         TQ_LOCK(queue);
 599         KASSERT((timeout_task->f & DT_DRAIN_IN_PROGRESS) == 0,
 600             ("Drain already in progress"));
 601         timeout_task->f |= DT_DRAIN_IN_PROGRESS;
 602         TQ_UNLOCK(queue);
 603
 604         callout_drain(&timeout_task->c);
 605         taskqueue_drain(queue, &timeout_task->t);
 606
 607         /*
 608          * Clear flag to allow timer to re-start:
 609          */
 610         TQ_LOCK(queue);
 611         timeout_task->f &= ~DT_DRAIN_IN_PROGRESS;
 612         TQ_UNLOCK(queue);
 613 }
 614
 615 static void
 616 taskqueue_swi_enqueue(void *context)
 617 {
 618         swi_sched(taskqueue_ih, 0);
 619 }
 620
 621 static void
 622 taskqueue_swi_run(void *dummy)
 623 {
 624         taskqueue_run(taskqueue_swi);
 625 }
 626
 627 static void
 628 taskqueue_swi_giant_enqueue(void *context)
 629 {
 630         swi_sched(taskqueue_giant_ih, 0);
 631 }
 632
 633 static void
 634 taskqueue_swi_giant_run(void *dummy)
 635 {
 636         taskqueue_run(taskqueue_swi_giant);
 637 }
 638
 639 static int
 640 _taskqueue_start_threads(struct taskqueue **tqp, int count, int pri,
 641     cpuset_t *mask, const char *name, va_list ap)
 642 {
 643         char ktname[MAXCOMLEN + 1];
 644         struct thread *td;
 645         struct taskqueue *tq;
 646         int i, error;
 647
 648         if (count <= 0)
 649                 return (EINVAL);
 650
 651         vsnprintf(ktname, sizeof(ktname), name, ap);
 652         tq = *tqp;
 653
 654         tq->tq_threads = malloc(sizeof(struct thread *) * count, M_TASKQUEUE,
 655             M_NOWAIT | M_ZERO);
 656         if (tq->tq_threads == NULL) {
 657                 printf("%s: no memory for %s threads\n", __func__, ktname);
 658                 return (ENOMEM);
 659         }
 660
 661         for (i = 0; i < count; i++) {
 662                 if (count == 1)
 663                         error = kthread_add(taskqueue_thread_loop, tqp, NULL,
 664                             &tq->tq_threads[i], RFSTOPPED, 0, "%s", ktname);
 665                 else
 666                         error = kthread_add(taskqueue_thread_loop, tqp, NULL,
 667                             &tq->tq_threads[i], RFSTOPPED, 0,
 668                             "%s_%d", ktname, i);
 669                 if (error) {
 670                         /* should be ok to continue, taskqueue_free will dtrt */
 671                         printf("%s: kthread_add(%s): error %d", __func__,
 672                             ktname, error);
 673                         tq->tq_threads[i] = NULL;               /* paranoid */
 674                 } else
 675                         tq->tq_tcount++;
 676         }
 677         if (tq->tq_tcount == 0) {
 678                 free(tq->tq_threads, M_TASKQUEUE);
 679                 tq->tq_threads = NULL;
 680                 return (ENOMEM);
 681         }
 682         for (i = 0; i < count; i++) {
 683                 if (tq->tq_threads[i] == NULL)
 684                         continue;
 685                 td = tq->tq_threads[i];
 686                 if (mask) {
 687                         error = cpuset_setthread(td->td_tid, mask);
 688                         /*
 689                          * Failing to pin is rarely an actual fatal error;
 690                          * it'll just affect performance.
 691                          */
 692                         if (error)
 693                                 printf("%s: curthread=%llu: can't pin; "
 694                                     "error=%d\n",
 695                                     __func__,
 696                                     (unsigned long long) td->td_tid,
 697                                     error);
 698                 }
 699                 thread_lock(td);
 700                 sched_prio(td, pri);
 701                 sched_add(td, SRQ_BORING);
 702                 thread_unlock(td);
 703         }
 704
 705         return (0);
 706 }
 707
 708 int
 709 taskqueue_start_threads(struct taskqueue **tqp, int count, int pri,
 710     const char *name, ...)
 711 {
 712         va_list ap;
 713         int error;
 714
 715         va_start(ap, name);
 716         error = _taskqueue_start_threads(tqp, count, pri, NULL, name, ap);
 717         va_end(ap);
 718         return (error);
 719 }
 720
 721 int
 722 taskqueue_start_threads_cpuset(struct taskqueue **tqp, int count, int pri,
 723     cpuset_t *mask, const char *name, ...)
 724 {
 725         va_list ap;
 726         int error;
 727
 728         va_start(ap, name);
 729         error = _taskqueue_start_threads(tqp, count, pri, mask, name, ap);
 730         va_end(ap);
 731         return (error);
 732 }
 733
 734 static inline void
 735 taskqueue_run_callback(struct taskqueue *tq,
 736     enum taskqueue_callback_type cb_type)
 737 {
 738         taskqueue_callback_fn tq_callback;
 739
 740         TQ_ASSERT_UNLOCKED(tq);
 741         tq_callback = tq->tq_callbacks[cb_type];
 742         if (tq_callback != NULL)
 743                 tq_callback(tq->tq_cb_contexts[cb_type]);
 744 }
 745
 746 void
 747 taskqueue_thread_loop(void *arg)
 748 {
 749         struct taskqueue **tqp, *tq;
 750
 751         tqp = arg;
 752         tq = *tqp;
 753         taskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_INIT);
 754         TQ_LOCK(tq);
 755         while ((tq->tq_flags & TQ_FLAGS_ACTIVE) != 0) {
 756                 /* XXX ? */
 757                 taskqueue_run_locked(tq);
 758                 /*
 759                  * Because taskqueue_run() can drop tq_mutex, we need to
 760                  * check if the TQ_FLAGS_ACTIVE flag wasn't removed in the
 761                  * meantime, which means we missed a wakeup.
 762                  */
 763                 if ((tq->tq_flags & TQ_FLAGS_ACTIVE) == 0)
 764                         break;
 765                 TQ_SLEEP(tq, tq, &tq->tq_mutex, 0, "-", 0);
 766         }
 767         taskqueue_run_locked(tq);
 768         /*
 769          * This thread is on its way out, so just drop the lock temporarily
 770          * in order to call the shutdown callback.  This allows the callback
 771          * to look at the taskqueue, even just before it dies.
 772          */
 773         TQ_UNLOCK(tq);
 774         taskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_SHUTDOWN);
 775         TQ_LOCK(tq);
 776
 777         /* rendezvous with thread that asked us to terminate */
 778         tq->tq_tcount--;
 779         wakeup_one(tq->tq_threads);
 780         TQ_UNLOCK(tq);
 781         kthread_exit();
 782 }
 783
 784 void
 785 taskqueue_thread_enqueue(void *context)
 786 {
 787         struct taskqueue **tqp, *tq;
 788
 789         tqp = context;
 790         tq = *tqp;
 791         wakeup_one(tq);
 792 }
 793
 794 TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, NULL,
 795                  swi_add(NULL, "task queue", taskqueue_swi_run, NULL, SWI_TQ,
 796                      INTR_MPSAFE, &taskqueue_ih));
 797
 798 TASKQUEUE_DEFINE(swi_giant, taskqueue_swi_giant_enqueue, NULL,
 799                  swi_add(NULL, "Giant taskq", taskqueue_swi_giant_run,
 800                      NULL, SWI_TQ_GIANT, 0, &taskqueue_giant_ih));
 801
 802 TASKQUEUE_DEFINE_THREAD(thread);
 803
 804 struct taskqueue *
 805 taskqueue_create_fast(const char *name, int mflags,
 806                  taskqueue_enqueue_fn enqueue, void *context)
 807 {
 808         return _taskqueue_create(name, mflags, enqueue, context,
 809                         MTX_SPIN, "fast_taskqueue");
 810 }
 811
 812 static void     *taskqueue_fast_ih;
 813
 814 static void
 815 taskqueue_fast_enqueue(void *context)
 816 {
 817         swi_sched(taskqueue_fast_ih, 0);
 818 }
 819
 820 static void
 821 taskqueue_fast_run(void *dummy)
 822 {
 823         taskqueue_run(taskqueue_fast);
 824 }
 825
 826 TASKQUEUE_FAST_DEFINE(fast, taskqueue_fast_enqueue, NULL,
 827         swi_add(NULL, "fast taskq", taskqueue_fast_run, NULL,
 828         SWI_TQ_FAST, INTR_MPSAFE, &taskqueue_fast_ih));
 829
 830 int
 831 taskqueue_member(struct taskqueue *queue, struct thread *td)
 832 {
 833         int i, j, ret = 0;
 834
 835         for (i = 0, j = 0; ; i++) {
 836                 if (queue->tq_threads[i] == NULL)
 837                         continue;
 838                 if (queue->tq_threads[i] == td) {
 839                         ret = 1;
 840                         break;
 841                 }
 842                 if (++j >= queue->tq_tcount)
 843                         break;
 844         }
 845         return (ret);
 846 }