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Tidy up the thread taskqueue implementation and close a lost wakeup race.

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Instead of creating a mutex that we msleep on but don't actually lock when
doing the corresponding wakeup(), in the kthread, lock the mutex associated
with our taskqueue and msleep while the queue is empty.  Assert that the
queue is locked when the callback function is called to wake the kthread.
This commit is contained in:
John Baldwin 2004-02-19 22:03:52 +00:00
parent c09eddb36d
commit 712f57d8ab
1 changed files with 9 additions and 14 deletions
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23
sys/kern/subr_taskqueue.c
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@ -235,28 +235,23 @@ taskqueue_swi_giant_run(void *dummy)
}
static void
taskqueue_kthread(void *arg)
taskqueue_thread_loop(void *arg)
{
struct mtx kthread_mutex;
bzero(&kthread_mutex, sizeof(kthread_mutex));
mtx_init(&kthread_mutex, "taskqueue kthread", NULL, MTX_DEF);
mtx_lock(&kthread_mutex);
for (;;) {
mtx_unlock(&kthread_mutex);
mtx_lock(&taskqueue_thread->tq_mutex);
while (STAILQ_EMPTY(&taskqueue_thread->tq_queue))
msleep(taskqueue_thread, &taskqueue_thread->tq_mutex,
PWAIT, "-", 0);
mtx_unlock(&taskqueue_thread->tq_mutex);
taskqueue_run(taskqueue_thread);
mtx_lock(&kthread_mutex);
msleep(&taskqueue_thread, &kthread_mutex, PWAIT, "tqthr", 0);
}
}
static void
taskqueue_thread_enqueue(void *context)
{
wakeup(&taskqueue_thread);
mtx_assert(&taskqueue_thread->tq_mutex, MA_OWNED);
wakeup(taskqueue_thread);
}
TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, 0,
@ -268,7 +263,7 @@ TASKQUEUE_DEFINE(swi_giant, taskqueue_swi_giant_enqueue, 0,
NULL, SWI_TQ_GIANT, 0, &taskqueue_giant_ih));
TASKQUEUE_DEFINE(thread, taskqueue_thread_enqueue, 0,
kthread_create(taskqueue_kthread, NULL,
kthread_create(taskqueue_thread_loop, NULL,
&taskqueue_thread_proc, 0, 0, "taskqueue"));
int