subr_taskqueue.c

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    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: releng/11.0/sys/kern/subr_taskqueue.c 304716 2016-08-24 01:56:30Z shurd $");
   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/libkern.h>
   38 #include <sys/limits.h>
   39 #include <sys/lock.h>
   40 #include <sys/malloc.h>
   41 #include <sys/mutex.h>
   42 #include <sys/proc.h>
   43 #include <sys/sched.h>
   44 #include <sys/smp.h>
   45 #include <sys/taskqueue.h>
   46 #include <sys/unistd.h>
   47 #include <machine/stdarg.h>
   48 
   49 static MALLOC_DEFINE(M_TASKQUEUE, "taskqueue", "Task Queues");
   50 static void     *taskqueue_giant_ih;
   51 static void     *taskqueue_ih;
   52 static void      taskqueue_fast_enqueue(void *);
   53 static void      taskqueue_swi_enqueue(void *);
   54 static void      taskqueue_swi_giant_enqueue(void *);
   55 
   56 struct taskqueue_busy {
   57         struct task     *tb_running;
   58         TAILQ_ENTRY(taskqueue_busy) tb_link;
   59 };
   60 
   61 struct task * const TB_DRAIN_WAITER = (struct task *)0x1;
   62 
   63 struct taskqueue {
   64         STAILQ_HEAD(, task)     tq_queue;
   65         taskqueue_enqueue_fn    tq_enqueue;
   66         void                    *tq_context;
   67         char                    *tq_name;
   68         TAILQ_HEAD(, taskqueue_busy) tq_active;
   69         struct mtx              tq_mutex;
   70         struct thread           **tq_threads;
   71         int                     tq_tcount;
   72         int                     tq_spin;
   73         int                     tq_flags;
   74         int                     tq_callouts;
   75         taskqueue_callback_fn   tq_callbacks[TASKQUEUE_NUM_CALLBACKS];
   76         void                    *tq_cb_contexts[TASKQUEUE_NUM_CALLBACKS];
   77 };
   78 
   79 #define TQ_FLAGS_ACTIVE         (1 << 0)
   80 #define TQ_FLAGS_BLOCKED        (1 << 1)
   81 #define TQ_FLAGS_UNLOCKED_ENQUEUE       (1 << 2)
   82 
   83 #define DT_CALLOUT_ARMED        (1 << 0)
   84 
   85 #define TQ_LOCK(tq)                                                     \
   86         do {                                                            \
   87                 if ((tq)->tq_spin)                                      \
   88                         mtx_lock_spin(&(tq)->tq_mutex);                 \
   89                 else                                                    \
   90                         mtx_lock(&(tq)->tq_mutex);                      \
   91         } while (0)
   92 #define TQ_ASSERT_LOCKED(tq)    mtx_assert(&(tq)->tq_mutex, MA_OWNED)
   93 
   94 #define TQ_UNLOCK(tq)                                                   \
   95         do {                                                            \
   96                 if ((tq)->tq_spin)                                      \
   97                         mtx_unlock_spin(&(tq)->tq_mutex);               \
   98                 else                                                    \
   99                         mtx_unlock(&(tq)->tq_mutex);                    \
  100         } while (0)
  101 #define TQ_ASSERT_UNLOCKED(tq)  mtx_assert(&(tq)->tq_mutex, MA_NOTOWNED)
  102 
  103 void
  104 _timeout_task_init(struct taskqueue *queue, struct timeout_task *timeout_task,
  105     int priority, task_fn_t func, void *context)
  106 {
  107 
  108         TASK_INIT(&timeout_task->t, priority, func, context);
  109         callout_init_mtx(&timeout_task->c, &queue->tq_mutex,
  110             CALLOUT_RETURNUNLOCKED);
  111         timeout_task->q = queue;
  112         timeout_task->f = 0;
  113 }
  114 
  115 static __inline int
  116 TQ_SLEEP(struct taskqueue *tq, void *p, struct mtx *m, int pri, const char *wm,
  117     int t)
  118 {
  119         if (tq->tq_spin)
  120                 return (msleep_spin(p, m, wm, t));
  121         return (msleep(p, m, pri, wm, t));
  122 }
  123 
  124 static struct taskqueue *
  125 _taskqueue_create(const char *name, int mflags,
  126                  taskqueue_enqueue_fn enqueue, void *context,
  127                  int mtxflags, const char *mtxname __unused)
  128 {
  129         struct taskqueue *queue;
  130         char *tq_name;
  131 
  132         tq_name = malloc(TASKQUEUE_NAMELEN, M_TASKQUEUE, mflags | M_ZERO);
  133         if (tq_name == NULL)
  134                 return (NULL);
  135 
  136         queue = malloc(sizeof(struct taskqueue), M_TASKQUEUE, mflags | M_ZERO);
  137         if (queue == NULL) {
  138                 free(tq_name, M_TASKQUEUE);
  139                 return (NULL);
  140         }
  141 
  142         snprintf(tq_name, TASKQUEUE_NAMELEN, "%s", (name) ? name : "taskqueue");
  143 
  144         STAILQ_INIT(&queue->tq_queue);
  145         TAILQ_INIT(&queue->tq_active);
  146         queue->tq_enqueue = enqueue;
  147         queue->tq_context = context;
  148         queue->tq_name = tq_name;
  149         queue->tq_spin = (mtxflags & MTX_SPIN) != 0;
  150         queue->tq_flags |= TQ_FLAGS_ACTIVE;
  151         if (enqueue == taskqueue_fast_enqueue ||
  152             enqueue == taskqueue_swi_enqueue ||
  153             enqueue == taskqueue_swi_giant_enqueue ||
  154             enqueue == taskqueue_thread_enqueue)
  155                 queue->tq_flags |= TQ_FLAGS_UNLOCKED_ENQUEUE;
  156         mtx_init(&queue->tq_mutex, tq_name, NULL, mtxflags);
  157 
  158         return (queue);
  159 }
  160 
  161 struct taskqueue *
  162 taskqueue_create(const char *name, int mflags,
  163                  taskqueue_enqueue_fn enqueue, void *context)
  164 {
  165 
  166         return _taskqueue_create(name, mflags, enqueue, context,
  167                         MTX_DEF, name);
  168 }
  169 
  170 void
  171 taskqueue_set_callback(struct taskqueue *queue,
  172     enum taskqueue_callback_type cb_type, taskqueue_callback_fn callback,
  173     void *context)
  174 {
  175 
  176         KASSERT(((cb_type >= TASKQUEUE_CALLBACK_TYPE_MIN) &&
  177             (cb_type <= TASKQUEUE_CALLBACK_TYPE_MAX)),
  178             ("Callback type %d not valid, must be %d-%d", cb_type,
  179             TASKQUEUE_CALLBACK_TYPE_MIN, TASKQUEUE_CALLBACK_TYPE_MAX));
  180         KASSERT((queue->tq_callbacks[cb_type] == NULL),
  181             ("Re-initialization of taskqueue callback?"));
  182 
  183         queue->tq_callbacks[cb_type] = callback;
  184         queue->tq_cb_contexts[cb_type] = context;
  185 }
  186 
  187 /*
  188  * Signal a taskqueue thread to terminate.
  189  */
  190 static void
  191 taskqueue_terminate(struct thread **pp, struct taskqueue *tq)
  192 {
  193 
  194         while (tq->tq_tcount > 0 || tq->tq_callouts > 0) {
  195                 wakeup(tq);
  196                 TQ_SLEEP(tq, pp, &tq->tq_mutex, PWAIT, "taskqueue_destroy", 0);
  197         }
  198 }
  199 
  200 void
  201 taskqueue_free(struct taskqueue *queue)
  202 {
  203 
  204         TQ_LOCK(queue);
  205         queue->tq_flags &= ~TQ_FLAGS_ACTIVE;
  206         taskqueue_terminate(queue->tq_threads, queue);
  207         KASSERT(TAILQ_EMPTY(&queue->tq_active), ("Tasks still running?"));
  208         KASSERT(queue->tq_callouts == 0, ("Armed timeout tasks"));
  209         mtx_destroy(&queue->tq_mutex);
  210         free(queue->tq_threads, M_TASKQUEUE);
  211         free(queue->tq_name, M_TASKQUEUE);
  212         free(queue, M_TASKQUEUE);
  213 }
  214 
  215 static int
  216 taskqueue_enqueue_locked(struct taskqueue *queue, struct task *task)
  217 {
  218         struct task *ins;
  219         struct task *prev;
  220 
  221         KASSERT(task->ta_func != NULL, ("enqueueing task with NULL func"));
  222         /*
  223          * Count multiple enqueues.
  224          */
  225         if (task->ta_pending) {
  226                 if (task->ta_pending < USHRT_MAX)
  227                         task->ta_pending++;
  228                 TQ_UNLOCK(queue);
  229                 return (0);
  230         }
  231 
  232         /*
  233          * Optimise the case when all tasks have the same priority.
  234          */
  235         prev = STAILQ_LAST(&queue->tq_queue, task, ta_link);
  236         if (!prev || prev->ta_priority >= task->ta_priority) {
  237                 STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link);
  238         } else {
  239                 prev = NULL;
  240                 for (ins = STAILQ_FIRST(&queue->tq_queue); ins;
  241                      prev = ins, ins = STAILQ_NEXT(ins, ta_link))
  242                         if (ins->ta_priority < task->ta_priority)
  243                                 break;
  244 
  245                 if (prev)
  246                         STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link);
  247                 else
  248                         STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link);
  249         }
  250 
  251         task->ta_pending = 1;
  252         if ((queue->tq_flags & TQ_FLAGS_UNLOCKED_ENQUEUE) != 0)
  253                 TQ_UNLOCK(queue);
  254         if ((queue->tq_flags & TQ_FLAGS_BLOCKED) == 0)
  255                 queue->tq_enqueue(queue->tq_context);
  256         if ((queue->tq_flags & TQ_FLAGS_UNLOCKED_ENQUEUE) == 0)
  257                 TQ_UNLOCK(queue);
  258 
  259         /* Return with lock released. */
  260         return (0);
  261 }
  262 
  263 int
  264 taskqueue_enqueue(struct taskqueue *queue, struct task *task)
  265 {
  266         int res;
  267 
  268         TQ_LOCK(queue);
  269         res = taskqueue_enqueue_locked(queue, task);
  270         /* The lock is released inside. */
  271 
  272         return (res);
  273 }
  274 
  275 static void
  276 taskqueue_timeout_func(void *arg)
  277 {
  278         struct taskqueue *queue;
  279         struct timeout_task *timeout_task;
  280 
  281         timeout_task = arg;
  282         queue = timeout_task->q;
  283         KASSERT((timeout_task->f & DT_CALLOUT_ARMED) != 0, ("Stray timeout"));
  284         timeout_task->f &= ~DT_CALLOUT_ARMED;
  285         queue->tq_callouts--;
  286         taskqueue_enqueue_locked(timeout_task->q, &timeout_task->t);
  287         /* The lock is released inside. */
  288 }
  289 
  290 int
  291 taskqueue_enqueue_timeout(struct taskqueue *queue,
  292     struct timeout_task *timeout_task, int ticks)
  293 {
  294         int res;
  295 
  296         TQ_LOCK(queue);
  297         KASSERT(timeout_task->q == NULL || timeout_task->q == queue,
  298             ("Migrated queue"));
  299         KASSERT(!queue->tq_spin, ("Timeout for spin-queue"));
  300         timeout_task->q = queue;
  301         res = timeout_task->t.ta_pending;
  302         if (ticks == 0) {
  303                 taskqueue_enqueue_locked(queue, &timeout_task->t);
  304                 /* The lock is released inside. */
  305         } else {
  306                 if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
  307                         res++;
  308                 } else {
  309                         queue->tq_callouts++;
  310                         timeout_task->f |= DT_CALLOUT_ARMED;
  311                         if (ticks < 0)
  312                                 ticks = -ticks; /* Ignore overflow. */
  313                 }
  314                 if (ticks > 0) {
  315                         callout_reset(&timeout_task->c, ticks,
  316                             taskqueue_timeout_func, timeout_task);
  317                 }
  318                 TQ_UNLOCK(queue);
  319         }
  320         return (res);
  321 }
  322 
  323 static void
  324 taskqueue_task_nop_fn(void *context, int pending)
  325 {
  326 }
  327 
  328 /*
  329  * Block until all currently queued tasks in this taskqueue
  330  * have begun execution.  Tasks queued during execution of
  331  * this function are ignored.
  332  */
  333 static void
  334 taskqueue_drain_tq_queue(struct taskqueue *queue)
  335 {
  336         struct task t_barrier;
  337 
  338         if (STAILQ_EMPTY(&queue->tq_queue))
  339                 return;
  340 
  341         /*
  342          * Enqueue our barrier after all current tasks, but with
  343          * the highest priority so that newly queued tasks cannot
  344          * pass it.  Because of the high priority, we can not use
  345          * taskqueue_enqueue_locked directly (which drops the lock
  346          * anyway) so just insert it at tail while we have the
  347          * queue lock.
  348          */
  349         TASK_INIT(&t_barrier, USHRT_MAX, taskqueue_task_nop_fn, &t_barrier);
  350         STAILQ_INSERT_TAIL(&queue->tq_queue, &t_barrier, ta_link);
  351         t_barrier.ta_pending = 1;
  352 
  353         /*
  354          * Once the barrier has executed, all previously queued tasks
  355          * have completed or are currently executing.
  356          */
  357         while (t_barrier.ta_pending != 0)
  358                 TQ_SLEEP(queue, &t_barrier, &queue->tq_mutex, PWAIT, "-", 0);
  359 }
  360 
  361 /*
  362  * Block until all currently executing tasks for this taskqueue
  363  * complete.  Tasks that begin execution during the execution
  364  * of this function are ignored.
  365  */
  366 static void
  367 taskqueue_drain_tq_active(struct taskqueue *queue)
  368 {
  369         struct taskqueue_busy tb_marker, *tb_first;
  370 
  371         if (TAILQ_EMPTY(&queue->tq_active))
  372                 return;
  373 
  374         /* Block taskq_terminate().*/
  375         queue->tq_callouts++;
  376 
  377         /*
  378          * Wait for all currently executing taskqueue threads
  379          * to go idle.
  380          */
  381         tb_marker.tb_running = TB_DRAIN_WAITER;
  382         TAILQ_INSERT_TAIL(&queue->tq_active, &tb_marker, tb_link);
  383         while (TAILQ_FIRST(&queue->tq_active) != &tb_marker)
  384                 TQ_SLEEP(queue, &tb_marker, &queue->tq_mutex, PWAIT, "-", 0);
  385         TAILQ_REMOVE(&queue->tq_active, &tb_marker, tb_link);
  386 
  387         /*
  388          * Wakeup any other drain waiter that happened to queue up
  389          * without any intervening active thread.
  390          */
  391         tb_first = TAILQ_FIRST(&queue->tq_active);
  392         if (tb_first != NULL && tb_first->tb_running == TB_DRAIN_WAITER)
  393                 wakeup(tb_first);
  394 
  395         /* Release taskqueue_terminate(). */
  396         queue->tq_callouts--;
  397         if ((queue->tq_flags & TQ_FLAGS_ACTIVE) == 0)
  398                 wakeup_one(queue->tq_threads);
  399 }
  400 
  401 void
  402 taskqueue_block(struct taskqueue *queue)
  403 {
  404 
  405         TQ_LOCK(queue);
  406         queue->tq_flags |= TQ_FLAGS_BLOCKED;
  407         TQ_UNLOCK(queue);
  408 }
  409 
  410 void
  411 taskqueue_unblock(struct taskqueue *queue)
  412 {
  413 
  414         TQ_LOCK(queue);
  415         queue->tq_flags &= ~TQ_FLAGS_BLOCKED;
  416         if (!STAILQ_EMPTY(&queue->tq_queue))
  417                 queue->tq_enqueue(queue->tq_context);
  418         TQ_UNLOCK(queue);
  419 }
  420 
  421 static void
  422 taskqueue_run_locked(struct taskqueue *queue)
  423 {
  424         struct taskqueue_busy tb;
  425         struct taskqueue_busy *tb_first;
  426         struct task *task;
  427         int pending;
  428 
  429         KASSERT(queue != NULL, ("tq is NULL"));
  430         TQ_ASSERT_LOCKED(queue);
  431         tb.tb_running = NULL;
  432 
  433         while (STAILQ_FIRST(&queue->tq_queue)) {
  434                 TAILQ_INSERT_TAIL(&queue->tq_active, &tb, tb_link);
  435 
  436                 /*
  437                  * Carefully remove the first task from the queue and
  438                  * zero its pending count.
  439                  */
  440                 task = STAILQ_FIRST(&queue->tq_queue);
  441                 KASSERT(task != NULL, ("task is NULL"));
  442                 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link);
  443                 pending = task->ta_pending;
  444                 task->ta_pending = 0;
  445                 tb.tb_running = task;
  446                 TQ_UNLOCK(queue);
  447 
  448                 KASSERT(task->ta_func != NULL, ("task->ta_func is NULL"));
  449                 task->ta_func(task->ta_context, pending);
  450 
  451                 TQ_LOCK(queue);
  452                 tb.tb_running = NULL;
  453                 wakeup(task);
  454 
  455                 TAILQ_REMOVE(&queue->tq_active, &tb, tb_link);
  456                 tb_first = TAILQ_FIRST(&queue->tq_active);
  457                 if (tb_first != NULL &&
  458                     tb_first->tb_running == TB_DRAIN_WAITER)
  459                         wakeup(tb_first);
  460         }
  461 }
  462 
  463 void
  464 taskqueue_run(struct taskqueue *queue)
  465 {
  466 
  467         TQ_LOCK(queue);
  468         taskqueue_run_locked(queue);
  469         TQ_UNLOCK(queue);
  470 }
  471 
  472 static int
  473 task_is_running(struct taskqueue *queue, struct task *task)
  474 {
  475         struct taskqueue_busy *tb;
  476 
  477         TQ_ASSERT_LOCKED(queue);
  478         TAILQ_FOREACH(tb, &queue->tq_active, tb_link) {
  479                 if (tb->tb_running == task)
  480                         return (1);
  481         }
  482         return (0);
  483 }
  484 
  485 static int
  486 taskqueue_cancel_locked(struct taskqueue *queue, struct task *task,
  487     u_int *pendp)
  488 {
  489 
  490         if (task->ta_pending > 0)
  491                 STAILQ_REMOVE(&queue->tq_queue, task, task, ta_link);
  492         if (pendp != NULL)
  493                 *pendp = task->ta_pending;
  494         task->ta_pending = 0;
  495         return (task_is_running(queue, task) ? EBUSY : 0);
  496 }
  497 
  498 int
  499 taskqueue_cancel(struct taskqueue *queue, struct task *task, u_int *pendp)
  500 {
  501         int error;
  502 
  503         TQ_LOCK(queue);
  504         error = taskqueue_cancel_locked(queue, task, pendp);
  505         TQ_UNLOCK(queue);
  506 
  507         return (error);
  508 }
  509 
  510 int
  511 taskqueue_cancel_timeout(struct taskqueue *queue,
  512     struct timeout_task *timeout_task, u_int *pendp)
  513 {
  514         u_int pending, pending1;
  515         int error;
  516 
  517         TQ_LOCK(queue);
  518         pending = !!(callout_stop(&timeout_task->c) > 0);
  519         error = taskqueue_cancel_locked(queue, &timeout_task->t, &pending1);
  520         if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
  521                 timeout_task->f &= ~DT_CALLOUT_ARMED;
  522                 queue->tq_callouts--;
  523         }
  524         TQ_UNLOCK(queue);
  525 
  526         if (pendp != NULL)
  527                 *pendp = pending + pending1;
  528         return (error);
  529 }
  530 
  531 void
  532 taskqueue_drain(struct taskqueue *queue, struct task *task)
  533 {
  534 
  535         if (!queue->tq_spin)
  536                 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
  537 
  538         TQ_LOCK(queue);
  539         while (task->ta_pending != 0 || task_is_running(queue, task))
  540                 TQ_SLEEP(queue, task, &queue->tq_mutex, PWAIT, "-", 0);
  541         TQ_UNLOCK(queue);
  542 }
  543 
  544 void
  545 taskqueue_drain_all(struct taskqueue *queue)
  546 {
  547 
  548         if (!queue->tq_spin)
  549                 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
  550 
  551         TQ_LOCK(queue);
  552         taskqueue_drain_tq_queue(queue);
  553         taskqueue_drain_tq_active(queue);
  554         TQ_UNLOCK(queue);
  555 }
  556 
  557 void
  558 taskqueue_drain_timeout(struct taskqueue *queue,
  559     struct timeout_task *timeout_task)
  560 {
  561 
  562         callout_drain(&timeout_task->c);
  563         taskqueue_drain(queue, &timeout_task->t);
  564 }
  565 
  566 static void
  567 taskqueue_swi_enqueue(void *context)
  568 {
  569         swi_sched(taskqueue_ih, 0);
  570 }
  571 
  572 static void
  573 taskqueue_swi_run(void *dummy)
  574 {
  575         taskqueue_run(taskqueue_swi);
  576 }
  577 
  578 static void
  579 taskqueue_swi_giant_enqueue(void *context)
  580 {
  581         swi_sched(taskqueue_giant_ih, 0);
  582 }
  583 
  584 static void
  585 taskqueue_swi_giant_run(void *dummy)
  586 {
  587         taskqueue_run(taskqueue_swi_giant);
  588 }
  589 
  590 static int
  591 _taskqueue_start_threads(struct taskqueue **tqp, int count, int pri,
  592     cpuset_t *mask, const char *name, va_list ap)
  593 {
  594         char ktname[MAXCOMLEN + 1];
  595         struct thread *td;
  596         struct taskqueue *tq;
  597         int i, error;
  598 
  599         if (count <= 0)
  600                 return (EINVAL);
  601 
  602         vsnprintf(ktname, sizeof(ktname), name, ap);
  603         tq = *tqp;
  604 
  605         tq->tq_threads = malloc(sizeof(struct thread *) * count, M_TASKQUEUE,
  606             M_NOWAIT | M_ZERO);
  607         if (tq->tq_threads == NULL) {
  608                 printf("%s: no memory for %s threads\n", __func__, ktname);
  609                 return (ENOMEM);
  610         }
  611 
  612         for (i = 0; i < count; i++) {
  613                 if (count == 1)
  614                         error = kthread_add(taskqueue_thread_loop, tqp, NULL,
  615                             &tq->tq_threads[i], RFSTOPPED, 0, "%s", ktname);
  616                 else
  617                         error = kthread_add(taskqueue_thread_loop, tqp, NULL,
  618                             &tq->tq_threads[i], RFSTOPPED, 0,
  619                             "%s_%d", ktname, i);
  620                 if (error) {
  621                         /* should be ok to continue, taskqueue_free will dtrt */
  622                         printf("%s: kthread_add(%s): error %d", __func__,
  623                             ktname, error);
  624                         tq->tq_threads[i] = NULL;               /* paranoid */
  625                 } else
  626                         tq->tq_tcount++;
  627         }
  628         for (i = 0; i < count; i++) {
  629                 if (tq->tq_threads[i] == NULL)
  630                         continue;
  631                 td = tq->tq_threads[i];
  632                 if (mask) {
  633                         error = cpuset_setthread(td->td_tid, mask);
  634                         /*
  635                          * Failing to pin is rarely an actual fatal error;
  636                          * it'll just affect performance.
  637                          */
  638                         if (error)
  639                                 printf("%s: curthread=%llu: can't pin; "
  640                                     "error=%d\n",
  641                                     __func__,
  642                                     (unsigned long long) td->td_tid,
  643                                     error);
  644                 }
  645                 thread_lock(td);
  646                 sched_prio(td, pri);
  647                 sched_add(td, SRQ_BORING);
  648                 thread_unlock(td);
  649         }
  650 
  651         return (0);
  652 }
  653 
  654 int
  655 taskqueue_start_threads(struct taskqueue **tqp, int count, int pri,
  656     const char *name, ...)
  657 {
  658         va_list ap;
  659         int error;
  660 
  661         va_start(ap, name);
  662         error = _taskqueue_start_threads(tqp, count, pri, NULL, name, ap);
  663         va_end(ap);
  664         return (error);
  665 }
  666 
  667 int
  668 taskqueue_start_threads_cpuset(struct taskqueue **tqp, int count, int pri,
  669     cpuset_t *mask, const char *name, ...)
  670 {
  671         va_list ap;
  672         int error;
  673 
  674         va_start(ap, name);
  675         error = _taskqueue_start_threads(tqp, count, pri, mask, name, ap);
  676         va_end(ap);
  677         return (error);
  678 }
  679 
  680 static inline void
  681 taskqueue_run_callback(struct taskqueue *tq,
  682     enum taskqueue_callback_type cb_type)
  683 {
  684         taskqueue_callback_fn tq_callback;
  685 
  686         TQ_ASSERT_UNLOCKED(tq);
  687         tq_callback = tq->tq_callbacks[cb_type];
  688         if (tq_callback != NULL)
  689                 tq_callback(tq->tq_cb_contexts[cb_type]);
  690 }
  691 
  692 void
  693 taskqueue_thread_loop(void *arg)
  694 {
  695         struct taskqueue **tqp, *tq;
  696 
  697         tqp = arg;
  698         tq = *tqp;
  699         taskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_INIT);
  700         TQ_LOCK(tq);
  701         while ((tq->tq_flags & TQ_FLAGS_ACTIVE) != 0) {
  702                 /* XXX ? */
  703                 taskqueue_run_locked(tq);
  704                 /*
  705                  * Because taskqueue_run() can drop tq_mutex, we need to
  706                  * check if the TQ_FLAGS_ACTIVE flag wasn't removed in the
  707                  * meantime, which means we missed a wakeup.
  708                  */
  709                 if ((tq->tq_flags & TQ_FLAGS_ACTIVE) == 0)
  710                         break;
  711                 TQ_SLEEP(tq, tq, &tq->tq_mutex, 0, "-", 0);
  712         }
  713         taskqueue_run_locked(tq);
  714         /*
  715          * This thread is on its way out, so just drop the lock temporarily
  716          * in order to call the shutdown callback.  This allows the callback
  717          * to look at the taskqueue, even just before it dies.
  718          */
  719         TQ_UNLOCK(tq);
  720         taskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_SHUTDOWN);
  721         TQ_LOCK(tq);
  722 
  723         /* rendezvous with thread that asked us to terminate */
  724         tq->tq_tcount--;
  725         wakeup_one(tq->tq_threads);
  726         TQ_UNLOCK(tq);
  727         kthread_exit();
  728 }
  729 
  730 void
  731 taskqueue_thread_enqueue(void *context)
  732 {
  733         struct taskqueue **tqp, *tq;
  734 
  735         tqp = context;
  736         tq = *tqp;
  737         wakeup_one(tq);
  738 }
  739 
  740 TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, NULL,
  741                  swi_add(NULL, "task queue", taskqueue_swi_run, NULL, SWI_TQ,
  742                      INTR_MPSAFE, &taskqueue_ih));
  743 
  744 TASKQUEUE_DEFINE(swi_giant, taskqueue_swi_giant_enqueue, NULL,
  745                  swi_add(NULL, "Giant taskq", taskqueue_swi_giant_run,
  746                      NULL, SWI_TQ_GIANT, 0, &taskqueue_giant_ih));
  747 
  748 TASKQUEUE_DEFINE_THREAD(thread);
  749 
  750 struct taskqueue *
  751 taskqueue_create_fast(const char *name, int mflags,
  752                  taskqueue_enqueue_fn enqueue, void *context)
  753 {
  754         return _taskqueue_create(name, mflags, enqueue, context,
  755                         MTX_SPIN, "fast_taskqueue");
  756 }
  757 
  758 static void     *taskqueue_fast_ih;
  759 
  760 static void
  761 taskqueue_fast_enqueue(void *context)
  762 {
  763         swi_sched(taskqueue_fast_ih, 0);
  764 }
  765 
  766 static void
  767 taskqueue_fast_run(void *dummy)
  768 {
  769         taskqueue_run(taskqueue_fast);
  770 }
  771 
  772 TASKQUEUE_FAST_DEFINE(fast, taskqueue_fast_enqueue, NULL,
  773         swi_add(NULL, "fast taskq", taskqueue_fast_run, NULL,
  774         SWI_TQ_FAST, INTR_MPSAFE, &taskqueue_fast_ih));
  775 
  776 int
  777 taskqueue_member(struct taskqueue *queue, struct thread *td)
  778 {
  779         int i, j, ret = 0;
  780 
  781         for (i = 0, j = 0; ; i++) {
  782                 if (queue->tq_threads[i] == NULL)
  783                         continue;
  784                 if (queue->tq_threads[i] == td) {
  785                         ret = 1;
  786                         break;
  787                 }
  788                 if (++j >= queue->tq_tcount)
  789                         break;
  790         }
  791         return (ret);
  792 }
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FreeBSD/Linux Kernel Cross Reference sys/kern/subr_taskqueue.c

FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_taskqueue.c
