freebsd-dev/sys/kern/subr_taskqueue.c
Alexander Motin 3db35ffa2a Some more taskqueue optimizations.
- Optimize enqueue for two task priority values by adding new tq_hint
field, pointing to the last task inserted into the middle of the list.
In case of more then two priority values it should halve average search.
 - Move tq_active insert/remove out of the taskqueue_run_locked loop.
Instead of dirtying few shared cache lines per task introduce different
mechanism to drain active tasks, based on task sequence number counter,
that uses only cache lines already present in cache.  Since the new
mechanism does not need ordering, switch tq_active from TAILQ to LIST.
 - Move static and dynamic struct taskqueue fields into different cache
lines.  Move lock into its own cache line, so that heavy lock spinning
by multiple waiting threads would not affect the running thread.
 - While there, correct some TQ_SLEEP() wait messages.

This change fixes certain ZFS write workloads, causing huge congestion
on taskqueue lock.  Those workloads combine some large block writes to
saturate the pool and trigger allocation throttling, which uses higher
priority tasks to requeue the delayed I/Os, with many small blocks to
generate deep queue of small tasks for taskqueue to sort.

MFC after:	1 week
Sponsored by:	iXsystems, Inc.
2019-11-01 22:49:44 +00:00

871 lines
21 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2000 Doug Rabson
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/cpuset.h>
#include <sys/interrupt.h>
#include <sys/kernel.h>
#include <sys/kthread.h>
#include <sys/libkern.h>
#include <sys/limits.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/sched.h>
#include <sys/smp.h>
#include <sys/taskqueue.h>
#include <sys/unistd.h>
#include <machine/stdarg.h>
static MALLOC_DEFINE(M_TASKQUEUE, "taskqueue", "Task Queues");
static void *taskqueue_giant_ih;
static void *taskqueue_ih;
static void taskqueue_fast_enqueue(void *);
static void taskqueue_swi_enqueue(void *);
static void taskqueue_swi_giant_enqueue(void *);
struct taskqueue_busy {
struct task *tb_running;
u_int tb_seq;
LIST_ENTRY(taskqueue_busy) tb_link;
};
struct taskqueue {
STAILQ_HEAD(, task) tq_queue;
LIST_HEAD(, taskqueue_busy) tq_active;
struct task *tq_hint;
u_int tq_seq;
int tq_callouts;
struct mtx_padalign tq_mutex;
taskqueue_enqueue_fn tq_enqueue;
void *tq_context;
char *tq_name;
struct thread **tq_threads;
int tq_tcount;
int tq_spin;
int tq_flags;
taskqueue_callback_fn tq_callbacks[TASKQUEUE_NUM_CALLBACKS];
void *tq_cb_contexts[TASKQUEUE_NUM_CALLBACKS];
};
#define TQ_FLAGS_ACTIVE (1 << 0)
#define TQ_FLAGS_BLOCKED (1 << 1)
#define TQ_FLAGS_UNLOCKED_ENQUEUE (1 << 2)
#define DT_CALLOUT_ARMED (1 << 0)
#define DT_DRAIN_IN_PROGRESS (1 << 1)
#define TQ_LOCK(tq) \
do { \
if ((tq)->tq_spin) \
mtx_lock_spin(&(tq)->tq_mutex); \
else \
mtx_lock(&(tq)->tq_mutex); \
} while (0)
#define TQ_ASSERT_LOCKED(tq) mtx_assert(&(tq)->tq_mutex, MA_OWNED)
#define TQ_UNLOCK(tq) \
do { \
if ((tq)->tq_spin) \
mtx_unlock_spin(&(tq)->tq_mutex); \
else \
mtx_unlock(&(tq)->tq_mutex); \
} while (0)
#define TQ_ASSERT_UNLOCKED(tq) mtx_assert(&(tq)->tq_mutex, MA_NOTOWNED)
void
_timeout_task_init(struct taskqueue *queue, struct timeout_task *timeout_task,
int priority, task_fn_t func, void *context)
{
TASK_INIT(&timeout_task->t, priority, func, context);
callout_init_mtx(&timeout_task->c, &queue->tq_mutex,
CALLOUT_RETURNUNLOCKED);
timeout_task->q = queue;
timeout_task->f = 0;
}
static __inline int
TQ_SLEEP(struct taskqueue *tq, void *p, const char *wm)
{
if (tq->tq_spin)
return (msleep_spin(p, (struct mtx *)&tq->tq_mutex, wm, 0));
return (msleep(p, &tq->tq_mutex, 0, wm, 0));
}
static struct taskqueue *
_taskqueue_create(const char *name, int mflags,
taskqueue_enqueue_fn enqueue, void *context,
int mtxflags, const char *mtxname __unused)
{
struct taskqueue *queue;
char *tq_name;
tq_name = malloc(TASKQUEUE_NAMELEN, M_TASKQUEUE, mflags | M_ZERO);
if (tq_name == NULL)
return (NULL);
queue = malloc(sizeof(struct taskqueue), M_TASKQUEUE, mflags | M_ZERO);
if (queue == NULL) {
free(tq_name, M_TASKQUEUE);
return (NULL);
}
snprintf(tq_name, TASKQUEUE_NAMELEN, "%s", (name) ? name : "taskqueue");
STAILQ_INIT(&queue->tq_queue);
LIST_INIT(&queue->tq_active);
queue->tq_enqueue = enqueue;
queue->tq_context = context;
queue->tq_name = tq_name;
queue->tq_spin = (mtxflags & MTX_SPIN) != 0;
queue->tq_flags |= TQ_FLAGS_ACTIVE;
if (enqueue == taskqueue_fast_enqueue ||
enqueue == taskqueue_swi_enqueue ||
enqueue == taskqueue_swi_giant_enqueue ||
enqueue == taskqueue_thread_enqueue)
queue->tq_flags |= TQ_FLAGS_UNLOCKED_ENQUEUE;
mtx_init(&queue->tq_mutex, tq_name, NULL, mtxflags);
return (queue);
}
struct taskqueue *
taskqueue_create(const char *name, int mflags,
taskqueue_enqueue_fn enqueue, void *context)
{
return _taskqueue_create(name, mflags, enqueue, context,
MTX_DEF, name);
}
void
taskqueue_set_callback(struct taskqueue *queue,
enum taskqueue_callback_type cb_type, taskqueue_callback_fn callback,
void *context)
{
KASSERT(((cb_type >= TASKQUEUE_CALLBACK_TYPE_MIN) &&
(cb_type <= TASKQUEUE_CALLBACK_TYPE_MAX)),
("Callback type %d not valid, must be %d-%d", cb_type,
TASKQUEUE_CALLBACK_TYPE_MIN, TASKQUEUE_CALLBACK_TYPE_MAX));
KASSERT((queue->tq_callbacks[cb_type] == NULL),
("Re-initialization of taskqueue callback?"));
queue->tq_callbacks[cb_type] = callback;
queue->tq_cb_contexts[cb_type] = context;
}
/*
* Signal a taskqueue thread to terminate.
*/
static void
taskqueue_terminate(struct thread **pp, struct taskqueue *tq)
{
while (tq->tq_tcount > 0 || tq->tq_callouts > 0) {
wakeup(tq);
TQ_SLEEP(tq, pp, "tq_destroy");
}
}
void
taskqueue_free(struct taskqueue *queue)
{
TQ_LOCK(queue);
queue->tq_flags &= ~TQ_FLAGS_ACTIVE;
taskqueue_terminate(queue->tq_threads, queue);
KASSERT(LIST_EMPTY(&queue->tq_active), ("Tasks still running?"));
KASSERT(queue->tq_callouts == 0, ("Armed timeout tasks"));
mtx_destroy(&queue->tq_mutex);
free(queue->tq_threads, M_TASKQUEUE);
free(queue->tq_name, M_TASKQUEUE);
free(queue, M_TASKQUEUE);
}
static int
taskqueue_enqueue_locked(struct taskqueue *queue, struct task *task)
{
struct task *ins;
struct task *prev;
KASSERT(task->ta_func != NULL, ("enqueueing task with NULL func"));
/*
* Count multiple enqueues.
*/
if (task->ta_pending) {
if (task->ta_pending < USHRT_MAX)
task->ta_pending++;
TQ_UNLOCK(queue);
return (0);
}
/*
* Optimise cases when all tasks use small set of priorities.
* In case of only one priority we always insert at the end.
* In case of two tq_hint typically gives the insertion point.
* In case of more then two tq_hint should halve the search.
*/
prev = STAILQ_LAST(&queue->tq_queue, task, ta_link);
if (!prev || prev->ta_priority >= task->ta_priority) {
STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link);
} else {
prev = queue->tq_hint;
if (prev && prev->ta_priority >= task->ta_priority) {
ins = STAILQ_NEXT(prev, ta_link);
} else {
prev = NULL;
ins = STAILQ_FIRST(&queue->tq_queue);
}
for (; ins; prev = ins, ins = STAILQ_NEXT(ins, ta_link))
if (ins->ta_priority < task->ta_priority)
break;
if (prev) {
STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link);
queue->tq_hint = task;
} else
STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link);
}
task->ta_pending = 1;
if ((queue->tq_flags & TQ_FLAGS_UNLOCKED_ENQUEUE) != 0)
TQ_UNLOCK(queue);
if ((queue->tq_flags & TQ_FLAGS_BLOCKED) == 0)
queue->tq_enqueue(queue->tq_context);
if ((queue->tq_flags & TQ_FLAGS_UNLOCKED_ENQUEUE) == 0)
TQ_UNLOCK(queue);
/* Return with lock released. */
return (0);
}
int
taskqueue_enqueue(struct taskqueue *queue, struct task *task)
{
int res;
TQ_LOCK(queue);
res = taskqueue_enqueue_locked(queue, task);
/* The lock is released inside. */
return (res);
}
static void
taskqueue_timeout_func(void *arg)
{
struct taskqueue *queue;
struct timeout_task *timeout_task;
timeout_task = arg;
queue = timeout_task->q;
KASSERT((timeout_task->f & DT_CALLOUT_ARMED) != 0, ("Stray timeout"));
timeout_task->f &= ~DT_CALLOUT_ARMED;
queue->tq_callouts--;
taskqueue_enqueue_locked(timeout_task->q, &timeout_task->t);
/* The lock is released inside. */
}
int
taskqueue_enqueue_timeout_sbt(struct taskqueue *queue,
struct timeout_task *timeout_task, sbintime_t sbt, sbintime_t pr, int flags)
{
int res;
TQ_LOCK(queue);
KASSERT(timeout_task->q == NULL || timeout_task->q == queue,
("Migrated queue"));
KASSERT(!queue->tq_spin, ("Timeout for spin-queue"));
timeout_task->q = queue;
res = timeout_task->t.ta_pending;
if (timeout_task->f & DT_DRAIN_IN_PROGRESS) {
/* Do nothing */
TQ_UNLOCK(queue);
res = -1;
} else if (sbt == 0) {
taskqueue_enqueue_locked(queue, &timeout_task->t);
/* The lock is released inside. */
} else {
if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
res++;
} else {
queue->tq_callouts++;
timeout_task->f |= DT_CALLOUT_ARMED;
if (sbt < 0)
sbt = -sbt; /* Ignore overflow. */
}
if (sbt > 0) {
callout_reset_sbt(&timeout_task->c, sbt, pr,
taskqueue_timeout_func, timeout_task, flags);
}
TQ_UNLOCK(queue);
}
return (res);
}
int
taskqueue_enqueue_timeout(struct taskqueue *queue,
struct timeout_task *ttask, int ticks)
{
return (taskqueue_enqueue_timeout_sbt(queue, ttask, ticks * tick_sbt,
0, 0));
}
static void
taskqueue_task_nop_fn(void *context, int pending)
{
}
/*
* Block until all currently queued tasks in this taskqueue
* have begun execution. Tasks queued during execution of
* this function are ignored.
*/
static int
taskqueue_drain_tq_queue(struct taskqueue *queue)
{
struct task t_barrier;
if (STAILQ_EMPTY(&queue->tq_queue))
return (0);
/*
* Enqueue our barrier after all current tasks, but with
* the highest priority so that newly queued tasks cannot
* pass it. Because of the high priority, we can not use
* taskqueue_enqueue_locked directly (which drops the lock
* anyway) so just insert it at tail while we have the
* queue lock.
*/
TASK_INIT(&t_barrier, USHRT_MAX, taskqueue_task_nop_fn, &t_barrier);
STAILQ_INSERT_TAIL(&queue->tq_queue, &t_barrier, ta_link);
queue->tq_hint = &t_barrier;
t_barrier.ta_pending = 1;
/*
* Once the barrier has executed, all previously queued tasks
* have completed or are currently executing.
*/
while (t_barrier.ta_pending != 0)
TQ_SLEEP(queue, &t_barrier, "tq_qdrain");
return (1);
}
/*
* Block until all currently executing tasks for this taskqueue
* complete. Tasks that begin execution during the execution
* of this function are ignored.
*/
static int
taskqueue_drain_tq_active(struct taskqueue *queue)
{
struct taskqueue_busy *tb;
u_int seq;
if (LIST_EMPTY(&queue->tq_active))
return (0);
/* Block taskq_terminate().*/
queue->tq_callouts++;
/* Wait for any active task with sequence from the past. */
seq = queue->tq_seq;
restart:
LIST_FOREACH(tb, &queue->tq_active, tb_link) {
if ((int)(tb->tb_seq - seq) <= 0) {
TQ_SLEEP(queue, tb->tb_running, "tq_adrain");
goto restart;
}
}
/* Release taskqueue_terminate(). */
queue->tq_callouts--;
if ((queue->tq_flags & TQ_FLAGS_ACTIVE) == 0)
wakeup_one(queue->tq_threads);
return (1);
}
void
taskqueue_block(struct taskqueue *queue)
{
TQ_LOCK(queue);
queue->tq_flags |= TQ_FLAGS_BLOCKED;
TQ_UNLOCK(queue);
}
void
taskqueue_unblock(struct taskqueue *queue)
{
TQ_LOCK(queue);
queue->tq_flags &= ~TQ_FLAGS_BLOCKED;
if (!STAILQ_EMPTY(&queue->tq_queue))
queue->tq_enqueue(queue->tq_context);
TQ_UNLOCK(queue);
}
static void
taskqueue_run_locked(struct taskqueue *queue)
{
struct taskqueue_busy tb;
struct task *task;
int pending;
KASSERT(queue != NULL, ("tq is NULL"));
TQ_ASSERT_LOCKED(queue);
tb.tb_running = NULL;
LIST_INSERT_HEAD(&queue->tq_active, &tb, tb_link);
while ((task = STAILQ_FIRST(&queue->tq_queue)) != NULL) {
STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link);
if (queue->tq_hint == task)
queue->tq_hint = NULL;
pending = task->ta_pending;
task->ta_pending = 0;
tb.tb_running = task;
tb.tb_seq = ++queue->tq_seq;
TQ_UNLOCK(queue);
KASSERT(task->ta_func != NULL, ("task->ta_func is NULL"));
task->ta_func(task->ta_context, pending);
TQ_LOCK(queue);
wakeup(task);
}
LIST_REMOVE(&tb, tb_link);
}
void
taskqueue_run(struct taskqueue *queue)
{
TQ_LOCK(queue);
taskqueue_run_locked(queue);
TQ_UNLOCK(queue);
}
static int
task_is_running(struct taskqueue *queue, struct task *task)
{
struct taskqueue_busy *tb;
TQ_ASSERT_LOCKED(queue);
LIST_FOREACH(tb, &queue->tq_active, tb_link) {
if (tb->tb_running == task)
return (1);
}
return (0);
}
/*
* Only use this function in single threaded contexts. It returns
* non-zero if the given task is either pending or running. Else the
* task is idle and can be queued again or freed.
*/
int
taskqueue_poll_is_busy(struct taskqueue *queue, struct task *task)
{
int retval;
TQ_LOCK(queue);
retval = task->ta_pending > 0 || task_is_running(queue, task);
TQ_UNLOCK(queue);
return (retval);
}
static int
taskqueue_cancel_locked(struct taskqueue *queue, struct task *task,
u_int *pendp)
{
if (task->ta_pending > 0) {
STAILQ_REMOVE(&queue->tq_queue, task, task, ta_link);
if (queue->tq_hint == task)
queue->tq_hint = NULL;
}
if (pendp != NULL)
*pendp = task->ta_pending;
task->ta_pending = 0;
return (task_is_running(queue, task) ? EBUSY : 0);
}
int
taskqueue_cancel(struct taskqueue *queue, struct task *task, u_int *pendp)
{
int error;
TQ_LOCK(queue);
error = taskqueue_cancel_locked(queue, task, pendp);
TQ_UNLOCK(queue);
return (error);
}
int
taskqueue_cancel_timeout(struct taskqueue *queue,
struct timeout_task *timeout_task, u_int *pendp)
{
u_int pending, pending1;
int error;
TQ_LOCK(queue);
pending = !!(callout_stop(&timeout_task->c) > 0);
error = taskqueue_cancel_locked(queue, &timeout_task->t, &pending1);
if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
timeout_task->f &= ~DT_CALLOUT_ARMED;
queue->tq_callouts--;
}
TQ_UNLOCK(queue);
if (pendp != NULL)
*pendp = pending + pending1;
return (error);
}
void
taskqueue_drain(struct taskqueue *queue, struct task *task)
{
if (!queue->tq_spin)
WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
TQ_LOCK(queue);
while (task->ta_pending != 0 || task_is_running(queue, task))
TQ_SLEEP(queue, task, "tq_drain");
TQ_UNLOCK(queue);
}
void
taskqueue_drain_all(struct taskqueue *queue)
{
if (!queue->tq_spin)
WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
TQ_LOCK(queue);
(void)taskqueue_drain_tq_queue(queue);
(void)taskqueue_drain_tq_active(queue);
TQ_UNLOCK(queue);
}
void
taskqueue_drain_timeout(struct taskqueue *queue,
struct timeout_task *timeout_task)
{
/*
* Set flag to prevent timer from re-starting during drain:
*/
TQ_LOCK(queue);
KASSERT((timeout_task->f & DT_DRAIN_IN_PROGRESS) == 0,
("Drain already in progress"));
timeout_task->f |= DT_DRAIN_IN_PROGRESS;
TQ_UNLOCK(queue);
callout_drain(&timeout_task->c);
taskqueue_drain(queue, &timeout_task->t);
/*
* Clear flag to allow timer to re-start:
*/
TQ_LOCK(queue);
timeout_task->f &= ~DT_DRAIN_IN_PROGRESS;
TQ_UNLOCK(queue);
}
void
taskqueue_quiesce(struct taskqueue *queue)
{
int ret;
TQ_LOCK(queue);
do {
ret = taskqueue_drain_tq_queue(queue);
if (ret == 0)
ret = taskqueue_drain_tq_active(queue);
} while (ret != 0);
TQ_UNLOCK(queue);
}
static void
taskqueue_swi_enqueue(void *context)
{
swi_sched(taskqueue_ih, 0);
}
static void
taskqueue_swi_run(void *dummy)
{
taskqueue_run(taskqueue_swi);
}
static void
taskqueue_swi_giant_enqueue(void *context)
{
swi_sched(taskqueue_giant_ih, 0);
}
static void
taskqueue_swi_giant_run(void *dummy)
{
taskqueue_run(taskqueue_swi_giant);
}
static int
_taskqueue_start_threads(struct taskqueue **tqp, int count, int pri,
cpuset_t *mask, struct proc *p, const char *name, va_list ap)
{
char ktname[MAXCOMLEN + 1];
struct thread *td;
struct taskqueue *tq;
int i, error;
if (count <= 0)
return (EINVAL);
vsnprintf(ktname, sizeof(ktname), name, ap);
tq = *tqp;
tq->tq_threads = malloc(sizeof(struct thread *) * count, M_TASKQUEUE,
M_NOWAIT | M_ZERO);
if (tq->tq_threads == NULL) {
printf("%s: no memory for %s threads\n", __func__, ktname);
return (ENOMEM);
}
for (i = 0; i < count; i++) {
if (count == 1)
error = kthread_add(taskqueue_thread_loop, tqp, p,
&tq->tq_threads[i], RFSTOPPED, 0, "%s", ktname);
else
error = kthread_add(taskqueue_thread_loop, tqp, p,
&tq->tq_threads[i], RFSTOPPED, 0,
"%s_%d", ktname, i);
if (error) {
/* should be ok to continue, taskqueue_free will dtrt */
printf("%s: kthread_add(%s): error %d", __func__,
ktname, error);
tq->tq_threads[i] = NULL; /* paranoid */
} else
tq->tq_tcount++;
}
if (tq->tq_tcount == 0) {
free(tq->tq_threads, M_TASKQUEUE);
tq->tq_threads = NULL;
return (ENOMEM);
}
for (i = 0; i < count; i++) {
if (tq->tq_threads[i] == NULL)
continue;
td = tq->tq_threads[i];
if (mask) {
error = cpuset_setthread(td->td_tid, mask);
/*
* Failing to pin is rarely an actual fatal error;
* it'll just affect performance.
*/
if (error)
printf("%s: curthread=%llu: can't pin; "
"error=%d\n",
__func__,
(unsigned long long) td->td_tid,
error);
}
thread_lock(td);
sched_prio(td, pri);
sched_add(td, SRQ_BORING);
thread_unlock(td);
}
return (0);
}
int
taskqueue_start_threads(struct taskqueue **tqp, int count, int pri,
const char *name, ...)
{
va_list ap;
int error;
va_start(ap, name);
error = _taskqueue_start_threads(tqp, count, pri, NULL, NULL, name, ap);
va_end(ap);
return (error);
}
int
taskqueue_start_threads_in_proc(struct taskqueue **tqp, int count, int pri,
struct proc *proc, const char *name, ...)
{
va_list ap;
int error;
va_start(ap, name);
error = _taskqueue_start_threads(tqp, count, pri, NULL, proc, name, ap);
va_end(ap);
return (error);
}
int
taskqueue_start_threads_cpuset(struct taskqueue **tqp, int count, int pri,
cpuset_t *mask, const char *name, ...)
{
va_list ap;
int error;
va_start(ap, name);
error = _taskqueue_start_threads(tqp, count, pri, mask, NULL, name, ap);
va_end(ap);
return (error);
}
static inline void
taskqueue_run_callback(struct taskqueue *tq,
enum taskqueue_callback_type cb_type)
{
taskqueue_callback_fn tq_callback;
TQ_ASSERT_UNLOCKED(tq);
tq_callback = tq->tq_callbacks[cb_type];
if (tq_callback != NULL)
tq_callback(tq->tq_cb_contexts[cb_type]);
}
void
taskqueue_thread_loop(void *arg)
{
struct taskqueue **tqp, *tq;
tqp = arg;
tq = *tqp;
taskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_INIT);
TQ_LOCK(tq);
while ((tq->tq_flags & TQ_FLAGS_ACTIVE) != 0) {
/* XXX ? */
taskqueue_run_locked(tq);
/*
* Because taskqueue_run() can drop tq_mutex, we need to
* check if the TQ_FLAGS_ACTIVE flag wasn't removed in the
* meantime, which means we missed a wakeup.
*/
if ((tq->tq_flags & TQ_FLAGS_ACTIVE) == 0)
break;
TQ_SLEEP(tq, tq, "-");
}
taskqueue_run_locked(tq);
/*
* This thread is on its way out, so just drop the lock temporarily
* in order to call the shutdown callback. This allows the callback
* to look at the taskqueue, even just before it dies.
*/
TQ_UNLOCK(tq);
taskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_SHUTDOWN);
TQ_LOCK(tq);
/* rendezvous with thread that asked us to terminate */
tq->tq_tcount--;
wakeup_one(tq->tq_threads);
TQ_UNLOCK(tq);
kthread_exit();
}
void
taskqueue_thread_enqueue(void *context)
{
struct taskqueue **tqp, *tq;
tqp = context;
tq = *tqp;
wakeup_any(tq);
}
TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, NULL,
swi_add(NULL, "task queue", taskqueue_swi_run, NULL, SWI_TQ,
INTR_MPSAFE, &taskqueue_ih));
TASKQUEUE_DEFINE(swi_giant, taskqueue_swi_giant_enqueue, NULL,
swi_add(NULL, "Giant taskq", taskqueue_swi_giant_run,
NULL, SWI_TQ_GIANT, 0, &taskqueue_giant_ih));
TASKQUEUE_DEFINE_THREAD(thread);
struct taskqueue *
taskqueue_create_fast(const char *name, int mflags,
taskqueue_enqueue_fn enqueue, void *context)
{
return _taskqueue_create(name, mflags, enqueue, context,
MTX_SPIN, "fast_taskqueue");
}
static void *taskqueue_fast_ih;
static void
taskqueue_fast_enqueue(void *context)
{
swi_sched(taskqueue_fast_ih, 0);
}
static void
taskqueue_fast_run(void *dummy)
{
taskqueue_run(taskqueue_fast);
}
TASKQUEUE_FAST_DEFINE(fast, taskqueue_fast_enqueue, NULL,
swi_add(NULL, "fast taskq", taskqueue_fast_run, NULL,
SWI_TQ_FAST, INTR_MPSAFE, &taskqueue_fast_ih));
int
taskqueue_member(struct taskqueue *queue, struct thread *td)
{
int i, j, ret = 0;
for (i = 0, j = 0; ; i++) {
if (queue->tq_threads[i] == NULL)
continue;
if (queue->tq_threads[i] == td) {
ret = 1;
break;
}
if (++j >= queue->tq_tcount)
break;
}
return (ret);
}