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         u_int                    tb_seq;
  61         LIST_ENTRY(taskqueue_busy) tb_link;
  62 };
  63
  64 struct taskqueue {
  65         STAILQ_HEAD(, task)     tq_queue;
  66         LIST_HEAD(, taskqueue_busy) tq_active;
  67         struct task             *tq_hint;
  68         u_int                   tq_seq;
  69         int                     tq_callouts;
  70         struct mtx_padalign     tq_mutex;
  71         taskqueue_enqueue_fn    tq_enqueue;
  72         void                    *tq_context;
  73         char                    *tq_name;
  74         struct thread           **tq_threads;
  75         int                     tq_tcount;
  76         int                     tq_spin;
  77         int                     tq_flags;
  78         taskqueue_callback_fn   tq_callbacks[TASKQUEUE_NUM_CALLBACKS];
  79         void                    *tq_cb_contexts[TASKQUEUE_NUM_CALLBACKS];
  80 };
  81
  82 #define TQ_FLAGS_ACTIVE         (1 << 0)
  83 #define TQ_FLAGS_BLOCKED        (1 << 1)
  84 #define TQ_FLAGS_UNLOCKED_ENQUEUE       (1 << 2)
  85
  86 #define DT_CALLOUT_ARMED        (1 << 0)
  87 #define DT_DRAIN_IN_PROGRESS    (1 << 1)
  88
  89 #define TQ_LOCK(tq)                                                     \
  90         do {                                                            \
  91                 if ((tq)->tq_spin)                                      \
  92                         mtx_lock_spin(&(tq)->tq_mutex);                 \
  93                 else                                                    \
  94                         mtx_lock(&(tq)->tq_mutex);                      \
  95         } while (0)
  96 #define TQ_ASSERT_LOCKED(tq)    mtx_assert(&(tq)->tq_mutex, MA_OWNED)
  97
  98 #define TQ_UNLOCK(tq)                                                   \
  99         do {                                                            \
 100                 if ((tq)->tq_spin)                                      \
 101                         mtx_unlock_spin(&(tq)->tq_mutex);               \
 102                 else                                                    \
 103                         mtx_unlock(&(tq)->tq_mutex);                    \
 104         } while (0)
 105 #define TQ_ASSERT_UNLOCKED(tq)  mtx_assert(&(tq)->tq_mutex, MA_NOTOWNED)
 106
 107 void
 108 _timeout_task_init(struct taskqueue *queue, struct timeout_task *timeout_task,
 109     int priority, task_fn_t func, void *context)
 110 {
 111
 112         TASK_INIT(&timeout_task->t, priority, func, context);
 113         callout_init_mtx(&timeout_task->c, &queue->tq_mutex,
 114             CALLOUT_RETURNUNLOCKED);
 115         timeout_task->q = queue;
 116         timeout_task->f = 0;
 117 }
 118
 119 static __inline int
 120 TQ_SLEEP(struct taskqueue *tq, void *p, const char *wm)
 121 {
 122         if (tq->tq_spin)
 123                 return (msleep_spin(p, (struct mtx *)&tq->tq_mutex, wm, 0));
 124         return (msleep(p, &tq->tq_mutex, 0, wm, 0));
 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         LIST_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_destroy");
 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(LIST_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 cases when all tasks use small set of priorities.
 237          * In case of only one priority we always insert at the end.
 238          * In case of two tq_hint typically gives the insertion point.
 239          * In case of more then two tq_hint should halve the search.
 240          */
 241         prev = STAILQ_LAST(&queue->tq_queue, task, ta_link);
 242         if (!prev || prev->ta_priority >= task->ta_priority) {
 243                 STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link);
 244         } else {
 245                 prev = queue->tq_hint;
 246                 if (prev && prev->ta_priority >= task->ta_priority) {
 247                         ins = STAILQ_NEXT(prev, ta_link);
 248                 } else {
 249                         prev = NULL;
 250                         ins = STAILQ_FIRST(&queue->tq_queue);
 251                 }
 252                 for (; ins; prev = ins, ins = STAILQ_NEXT(ins, ta_link))
 253                         if (ins->ta_priority < task->ta_priority)
 254                                 break;
 255
 256                 if (prev) {
 257                         STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link);
 258                         queue->tq_hint = task;
 259                 } else
 260                         STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link);
 261         }
 262
 263         task->ta_pending = 1;
 264         if ((queue->tq_flags & TQ_FLAGS_UNLOCKED_ENQUEUE) != 0)
 265                 TQ_UNLOCK(queue);
 266         if ((queue->tq_flags & TQ_FLAGS_BLOCKED) == 0)
 267                 queue->tq_enqueue(queue->tq_context);
 268         if ((queue->tq_flags & TQ_FLAGS_UNLOCKED_ENQUEUE) == 0)
 269                 TQ_UNLOCK(queue);
 270
 271         /* Return with lock released. */
 272         return (0);
 273 }
 274
 275 int
 276 taskqueue_enqueue(struct taskqueue *queue, struct task *task)
 277 {
 278         int res;
 279
 280         TQ_LOCK(queue);
 281         res = taskqueue_enqueue_locked(queue, task);
 282         /* The lock is released inside. */
 283
 284         return (res);
 285 }
 286
 287 static void
 288 taskqueue_timeout_func(void *arg)
 289 {
 290         struct taskqueue *queue;
 291         struct timeout_task *timeout_task;
 292
 293         timeout_task = arg;
 294         queue = timeout_task->q;
 295         KASSERT((timeout_task->f & DT_CALLOUT_ARMED) != 0, ("Stray timeout"));
 296         timeout_task->f &= ~DT_CALLOUT_ARMED;
 297         queue->tq_callouts--;
 298         taskqueue_enqueue_locked(timeout_task->q, &timeout_task->t);
 299         /* The lock is released inside. */
 300 }
 301
 302 int
 303 taskqueue_enqueue_timeout_sbt(struct taskqueue *queue,
 304     struct timeout_task *timeout_task, sbintime_t sbt, sbintime_t pr, int flags)
 305 {
 306         int res;
 307
 308         TQ_LOCK(queue);
 309         KASSERT(timeout_task->q == NULL || timeout_task->q == queue,
 310             ("Migrated queue"));
 311         KASSERT(!queue->tq_spin, ("Timeout for spin-queue"));
 312         timeout_task->q = queue;
 313         res = timeout_task->t.ta_pending;
 314         if (timeout_task->f & DT_DRAIN_IN_PROGRESS) {
 315                 /* Do nothing */
 316                 TQ_UNLOCK(queue);
 317                 res = -1;
 318         } else if (sbt == 0) {
 319                 taskqueue_enqueue_locked(queue, &timeout_task->t);
 320                 /* The lock is released inside. */
 321         } else {
 322                 if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
 323                         res++;
 324                 } else {
 325                         queue->tq_callouts++;
 326                         timeout_task->f |= DT_CALLOUT_ARMED;
 327                         if (sbt < 0)
 328                                 sbt = -sbt; /* Ignore overflow. */
 329                 }
 330                 if (sbt > 0) {
 331                         callout_reset_sbt(&timeout_task->c, sbt, pr,
 332                             taskqueue_timeout_func, timeout_task, flags);
 333                 }
 334                 TQ_UNLOCK(queue);
 335         }
 336         return (res);
 337 }
 338
 339 int
 340 taskqueue_enqueue_timeout(struct taskqueue *queue,
 341     struct timeout_task *ttask, int ticks)
 342 {
 343
 344         return (taskqueue_enqueue_timeout_sbt(queue, ttask, ticks * tick_sbt,
 345             0, 0));
 346 }
 347
 348 static void
 349 taskqueue_task_nop_fn(void *context, int pending)
 350 {
 351 }
 352
 353 /*
 354  * Block until all currently queued tasks in this taskqueue
 355  * have begun execution.  Tasks queued during execution of
 356  * this function are ignored.
 357  */
 358 static int
 359 taskqueue_drain_tq_queue(struct taskqueue *queue)
 360 {
 361         struct task t_barrier;
 362
 363         if (STAILQ_EMPTY(&queue->tq_queue))
 364                 return (0);
 365
 366         /*
 367          * Enqueue our barrier after all current tasks, but with
 368          * the highest priority so that newly queued tasks cannot
 369          * pass it.  Because of the high priority, we can not use
 370          * taskqueue_enqueue_locked directly (which drops the lock
 371          * anyway) so just insert it at tail while we have the
 372          * queue lock.
 373          */
 374         TASK_INIT(&t_barrier, USHRT_MAX, taskqueue_task_nop_fn, &t_barrier);
 375         STAILQ_INSERT_TAIL(&queue->tq_queue, &t_barrier, ta_link);
 376         queue->tq_hint = &t_barrier;
 377         t_barrier.ta_pending = 1;
 378
 379         /*
 380          * Once the barrier has executed, all previously queued tasks
 381          * have completed or are currently executing.
 382          */
 383         while (t_barrier.ta_pending != 0)
 384                 TQ_SLEEP(queue, &t_barrier, "tq_qdrain");
 385         return (1);
 386 }
 387
 388 /*
 389  * Block until all currently executing tasks for this taskqueue
 390  * complete.  Tasks that begin execution during the execution
 391  * of this function are ignored.
 392  */
 393 static int
 394 taskqueue_drain_tq_active(struct taskqueue *queue)
 395 {
 396         struct taskqueue_busy *tb;
 397         u_int seq;
 398
 399         if (LIST_EMPTY(&queue->tq_active))
 400                 return (0);
 401
 402         /* Block taskq_terminate().*/
 403         queue->tq_callouts++;
 404
 405         /* Wait for any active task with sequence from the past. */
 406         seq = queue->tq_seq;
 407 restart:
 408         LIST_FOREACH(tb, &queue->tq_active, tb_link) {
 409                 if ((int)(tb->tb_seq - seq) <= 0) {
 410                         TQ_SLEEP(queue, tb->tb_running, "tq_adrain");
 411                         goto restart;
 412                 }
 413         }
 414
 415         /* Release taskqueue_terminate(). */
 416         queue->tq_callouts--;
 417         if ((queue->tq_flags & TQ_FLAGS_ACTIVE) == 0)
 418                 wakeup_one(queue->tq_threads);
 419         return (1);
 420 }
 421
 422 void
 423 taskqueue_block(struct taskqueue *queue)
 424 {
 425
 426         TQ_LOCK(queue);
 427         queue->tq_flags |= TQ_FLAGS_BLOCKED;
 428         TQ_UNLOCK(queue);
 429 }
 430
 431 void
 432 taskqueue_unblock(struct taskqueue *queue)
 433 {
 434
 435         TQ_LOCK(queue);
 436         queue->tq_flags &= ~TQ_FLAGS_BLOCKED;
 437         if (!STAILQ_EMPTY(&queue->tq_queue))
 438                 queue->tq_enqueue(queue->tq_context);
 439         TQ_UNLOCK(queue);
 440 }
 441
 442 static void
 443 taskqueue_run_locked(struct taskqueue *queue)
 444 {
 445         struct taskqueue_busy tb;
 446         struct task *task;
 447         int pending;
 448
 449         KASSERT(queue != NULL, ("tq is NULL"));
 450         TQ_ASSERT_LOCKED(queue);
 451         tb.tb_running = NULL;
 452         LIST_INSERT_HEAD(&queue->tq_active, &tb, tb_link);
 453
 454         while ((task = STAILQ_FIRST(&queue->tq_queue)) != NULL) {
 455                 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link);
 456                 if (queue->tq_hint == task)
 457                         queue->tq_hint = NULL;
 458                 pending = task->ta_pending;
 459                 task->ta_pending = 0;
 460                 tb.tb_running = task;
 461                 tb.tb_seq = ++queue->tq_seq;
 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                 wakeup(task);
 469         }
 470         LIST_REMOVE(&tb, tb_link);
 471 }
 472
 473 void
 474 taskqueue_run(struct taskqueue *queue)
 475 {
 476
 477         TQ_LOCK(queue);
 478         taskqueue_run_locked(queue);
 479         TQ_UNLOCK(queue);
 480 }
 481
 482 static int
 483 task_is_running(struct taskqueue *queue, struct task *task)
 484 {
 485         struct taskqueue_busy *tb;
 486
 487         TQ_ASSERT_LOCKED(queue);
 488         LIST_FOREACH(tb, &queue->tq_active, tb_link) {
 489                 if (tb->tb_running == task)
 490                         return (1);
 491         }
 492         return (0);
 493 }
 494
 495 /*
 496  * Only use this function in single threaded contexts. It returns
 497  * non-zero if the given task is either pending or running. Else the
 498  * task is idle and can be queued again or freed.
 499  */
 500 int
 501 taskqueue_poll_is_busy(struct taskqueue *queue, struct task *task)
 502 {
 503         int retval;
 504
 505         TQ_LOCK(queue);
 506         retval = task->ta_pending > 0 || task_is_running(queue, task);
 507         TQ_UNLOCK(queue);
 508
 509         return (retval);
 510 }
 511
 512 static int
 513 taskqueue_cancel_locked(struct taskqueue *queue, struct task *task,
 514     u_int *pendp)
 515 {
 516
 517         if (task->ta_pending > 0) {
 518                 STAILQ_REMOVE(&queue->tq_queue, task, task, ta_link);
 519                 if (queue->tq_hint == task)
 520                         queue->tq_hint = NULL;
 521         }
 522         if (pendp != NULL)
 523                 *pendp = task->ta_pending;
 524         task->ta_pending = 0;
 525         return (task_is_running(queue, task) ? EBUSY : 0);
 526 }
 527
 528 int
 529 taskqueue_cancel(struct taskqueue *queue, struct task *task, u_int *pendp)
 530 {
 531         int error;
 532
 533         TQ_LOCK(queue);
 534         error = taskqueue_cancel_locked(queue, task, pendp);
 535         TQ_UNLOCK(queue);
 536
 537         return (error);
 538 }
 539
 540 int
 541 taskqueue_cancel_timeout(struct taskqueue *queue,
 542     struct timeout_task *timeout_task, u_int *pendp)
 543 {
 544         u_int pending, pending1;
 545         int error;
 546
 547         TQ_LOCK(queue);
 548         pending = !!(callout_stop(&timeout_task->c) > 0);
 549         error = taskqueue_cancel_locked(queue, &timeout_task->t, &pending1);
 550         if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
 551                 timeout_task->f &= ~DT_CALLOUT_ARMED;
 552                 queue->tq_callouts--;
 553         }
 554         TQ_UNLOCK(queue);
 555
 556         if (pendp != NULL)
 557                 *pendp = pending + pending1;
 558         return (error);
 559 }
 560
 561 void
 562 taskqueue_drain(struct taskqueue *queue, struct task *task)
 563 {
 564
 565         if (!queue->tq_spin)
 566                 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
 567
 568         TQ_LOCK(queue);
 569         while (task->ta_pending != 0 || task_is_running(queue, task))
 570                 TQ_SLEEP(queue, task, "tq_drain");
 571         TQ_UNLOCK(queue);
 572 }
 573
 574 void
 575 taskqueue_drain_all(struct taskqueue *queue)
 576 {
 577
 578         if (!queue->tq_spin)
 579                 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
 580
 581         TQ_LOCK(queue);
 582         (void)taskqueue_drain_tq_queue(queue);
 583         (void)taskqueue_drain_tq_active(queue);
 584         TQ_UNLOCK(queue);
 585 }
 586
 587 void
 588 taskqueue_drain_timeout(struct taskqueue *queue,
 589     struct timeout_task *timeout_task)
 590 {
 591
 592         /*
 593          * Set flag to prevent timer from re-starting during drain:
 594          */
 595         TQ_LOCK(queue);
 596         KASSERT((timeout_task->f & DT_DRAIN_IN_PROGRESS) == 0,
 597             ("Drain already in progress"));
 598         timeout_task->f |= DT_DRAIN_IN_PROGRESS;
 599         TQ_UNLOCK(queue);
 600
 601         callout_drain(&timeout_task->c);
 602         taskqueue_drain(queue, &timeout_task->t);
 603
 604         /*
 605          * Clear flag to allow timer to re-start:
 606          */
 607         TQ_LOCK(queue);
 608         timeout_task->f &= ~DT_DRAIN_IN_PROGRESS;
 609         TQ_UNLOCK(queue);
 610 }
 611
 612 void
 613 taskqueue_quiesce(struct taskqueue *queue)
 614 {
 615         int ret;
 616
 617         TQ_LOCK(queue);
 618         do {
 619                 ret = taskqueue_drain_tq_queue(queue);
 620                 if (ret == 0)
 621                         ret = taskqueue_drain_tq_active(queue);
 622         } while (ret != 0);
 623         TQ_UNLOCK(queue);
 624 }
 625
 626 static void
 627 taskqueue_swi_enqueue(void *context)
 628 {
 629         swi_sched(taskqueue_ih, 0);
 630 }
 631
 632 static void
 633 taskqueue_swi_run(void *dummy)
 634 {
 635         taskqueue_run(taskqueue_swi);
 636 }
 637
 638 static void
 639 taskqueue_swi_giant_enqueue(void *context)
 640 {
 641         swi_sched(taskqueue_giant_ih, 0);
 642 }
 643
 644 static void
 645 taskqueue_swi_giant_run(void *dummy)
 646 {
 647         taskqueue_run(taskqueue_swi_giant);
 648 }
 649
 650 static int
 651 _taskqueue_start_threads(struct taskqueue **tqp, int count, int pri,
 652     cpuset_t *mask, struct proc *p, const char *name, va_list ap)
 653 {
 654         char ktname[MAXCOMLEN + 1];
 655         struct thread *td;
 656         struct taskqueue *tq;
 657         int i, error;
 658
 659         if (count <= 0)
 660                 return (EINVAL);
 661
 662         vsnprintf(ktname, sizeof(ktname), name, ap);
 663         tq = *tqp;
 664
 665         tq->tq_threads = malloc(sizeof(struct thread *) * count, M_TASKQUEUE,
 666             M_NOWAIT | M_ZERO);
 667         if (tq->tq_threads == NULL) {
 668                 printf("%s: no memory for %s threads\n", __func__, ktname);
 669                 return (ENOMEM);
 670         }
 671
 672         for (i = 0; i < count; i++) {
 673                 if (count == 1)
 674                         error = kthread_add(taskqueue_thread_loop, tqp, p,
 675                             &tq->tq_threads[i], RFSTOPPED, 0, "%s", ktname);
 676                 else
 677                         error = kthread_add(taskqueue_thread_loop, tqp, p,
 678                             &tq->tq_threads[i], RFSTOPPED, 0,
 679                             "%s_%d", ktname, i);
 680                 if (error) {
 681                         /* should be ok to continue, taskqueue_free will dtrt */
 682                         printf("%s: kthread_add(%s): error %d", __func__,
 683                             ktname, error);
 684                         tq->tq_threads[i] = NULL;               /* paranoid */
 685                 } else
 686                         tq->tq_tcount++;
 687         }
 688         if (tq->tq_tcount == 0) {
 689                 free(tq->tq_threads, M_TASKQUEUE);
 690                 tq->tq_threads = NULL;
 691                 return (ENOMEM);
 692         }
 693         for (i = 0; i < count; i++) {
 694                 if (tq->tq_threads[i] == NULL)
 695                         continue;
 696                 td = tq->tq_threads[i];
 697                 if (mask) {
 698                         error = cpuset_setthread(td->td_tid, mask);
 699                         /*
 700                          * Failing to pin is rarely an actual fatal error;
 701                          * it'll just affect performance.
 702                          */
 703                         if (error)
 704                                 printf("%s: curthread=%llu: can't pin; "
 705                                     "error=%d\n",
 706                                     __func__,
 707                                     (unsigned long long) td->td_tid,
 708                                     error);
 709                 }
 710                 thread_lock(td);
 711                 sched_prio(td, pri);
 712                 sched_add(td, SRQ_BORING);
 713                 thread_unlock(td);
 714         }
 715
 716         return (0);
 717 }
 718
 719 int
 720 taskqueue_start_threads(struct taskqueue **tqp, int count, int pri,
 721     const char *name, ...)
 722 {
 723         va_list ap;
 724         int error;
 725
 726         va_start(ap, name);
 727         error = _taskqueue_start_threads(tqp, count, pri, NULL, NULL, name, ap);
 728         va_end(ap);
 729         return (error);
 730 }
 731
 732 int
 733 taskqueue_start_threads_in_proc(struct taskqueue **tqp, int count, int pri,
 734     struct proc *proc, const char *name, ...)
 735 {
 736         va_list ap;
 737         int error;
 738
 739         va_start(ap, name);
 740         error = _taskqueue_start_threads(tqp, count, pri, NULL, proc, name, ap);
 741         va_end(ap);
 742         return (error);
 743 }
 744
 745 int
 746 taskqueue_start_threads_cpuset(struct taskqueue **tqp, int count, int pri,
 747     cpuset_t *mask, const char *name, ...)
 748 {
 749         va_list ap;
 750         int error;
 751
 752         va_start(ap, name);
 753         error = _taskqueue_start_threads(tqp, count, pri, mask, NULL, name, ap);
 754         va_end(ap);
 755         return (error);
 756 }
 757
 758 static inline void
 759 taskqueue_run_callback(struct taskqueue *tq,
 760     enum taskqueue_callback_type cb_type)
 761 {
 762         taskqueue_callback_fn tq_callback;
 763
 764         TQ_ASSERT_UNLOCKED(tq);
 765         tq_callback = tq->tq_callbacks[cb_type];
 766         if (tq_callback != NULL)
 767                 tq_callback(tq->tq_cb_contexts[cb_type]);
 768 }
 769
 770 void
 771 taskqueue_thread_loop(void *arg)
 772 {
 773         struct taskqueue **tqp, *tq;
 774
 775         tqp = arg;
 776         tq = *tqp;
 777         taskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_INIT);
 778         TQ_LOCK(tq);
 779         while ((tq->tq_flags & TQ_FLAGS_ACTIVE) != 0) {
 780                 /* XXX ? */
 781                 taskqueue_run_locked(tq);
 782                 /*
 783                  * Because taskqueue_run() can drop tq_mutex, we need to
 784                  * check if the TQ_FLAGS_ACTIVE flag wasn't removed in the
 785                  * meantime, which means we missed a wakeup.
 786                  */
 787                 if ((tq->tq_flags & TQ_FLAGS_ACTIVE) == 0)
 788                         break;
 789                 TQ_SLEEP(tq, tq, "-");
 790         }
 791         taskqueue_run_locked(tq);
 792         /*
 793          * This thread is on its way out, so just drop the lock temporarily
 794          * in order to call the shutdown callback.  This allows the callback
 795          * to look at the taskqueue, even just before it dies.
 796          */
 797         TQ_UNLOCK(tq);
 798         taskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_SHUTDOWN);
 799         TQ_LOCK(tq);
 800
 801         /* rendezvous with thread that asked us to terminate */
 802         tq->tq_tcount--;
 803         wakeup_one(tq->tq_threads);
 804         TQ_UNLOCK(tq);
 805         kthread_exit();
 806 }
 807
 808 void
 809 taskqueue_thread_enqueue(void *context)
 810 {
 811         struct taskqueue **tqp, *tq;
 812
 813         tqp = context;
 814         tq = *tqp;
 815         wakeup_any(tq);
 816 }
 817
 818 TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, NULL,
 819                  swi_add(NULL, "task queue", taskqueue_swi_run, NULL, SWI_TQ,
 820                      INTR_MPSAFE, &taskqueue_ih));
 821
 822 TASKQUEUE_DEFINE(swi_giant, taskqueue_swi_giant_enqueue, NULL,
 823                  swi_add(NULL, "Giant taskq", taskqueue_swi_giant_run,
 824                      NULL, SWI_TQ_GIANT, 0, &taskqueue_giant_ih));
 825
 826 TASKQUEUE_DEFINE_THREAD(thread);
 827
 828 struct taskqueue *
 829 taskqueue_create_fast(const char *name, int mflags,
 830                  taskqueue_enqueue_fn enqueue, void *context)
 831 {
 832         return _taskqueue_create(name, mflags, enqueue, context,
 833                         MTX_SPIN, "fast_taskqueue");
 834 }
 835
 836 static void     *taskqueue_fast_ih;
 837
 838 static void
 839 taskqueue_fast_enqueue(void *context)
 840 {
 841         swi_sched(taskqueue_fast_ih, 0);
 842 }
 843
 844 static void
 845 taskqueue_fast_run(void *dummy)
 846 {
 847         taskqueue_run(taskqueue_fast);
 848 }
 849
 850 TASKQUEUE_FAST_DEFINE(fast, taskqueue_fast_enqueue, NULL,
 851         swi_add(NULL, "fast taskq", taskqueue_fast_run, NULL,
 852         SWI_TQ_FAST, INTR_MPSAFE, &taskqueue_fast_ih));
 853
 854 int
 855 taskqueue_member(struct taskqueue *queue, struct thread *td)
 856 {
 857         int i, j, ret = 0;
 858
 859         for (i = 0, j = 0; ; i++) {
 860                 if (queue->tq_threads[i] == NULL)
 861                         continue;
 862                 if (queue->tq_threads[i] == td) {
 863                         ret = 1;
 864                         break;
 865                 }
 866                 if (++j >= queue->tq_tcount)
 867                         break;
 868         }
 869         return (ret);
 870 }