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MFprojects/camlock r254763:

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Move tq_enqueue() call out of the queue lock for known handlers (actually
I have found no others in the base system).  This reduces queue lock hold
time and congestion spinning under active multithreaded enqueuing.
This commit is contained in:
Alexander Motin 2013-10-16 09:52:59 +00:00
parent 1d1e92f102
commit 6d545f4c8d
1 changed files with 17 additions and 4 deletions
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21
sys/kern/subr_taskqueue.c
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@ -47,6 +47,9 @@ __FBSDID("$FreeBSD$");
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;
@ -70,6 +73,7 @@ struct taskqueue {
#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)
@ -97,7 +101,8 @@ _timeout_task_init(struct taskqueue *queue, struct timeout_task *timeout_task,
{
TASK_INIT(&timeout_task->t, priority, func, context);
callout_init_mtx(&timeout_task->c, &queue->tq_mutex, 0);
callout_init_mtx(&timeout_task->c, &queue->tq_mutex,
CALLOUT_RETURNUNLOCKED);
timeout_task->q = queue;
timeout_task->f = 0;
}
@ -128,6 +133,11 @@ _taskqueue_create(const char *name __unused, int mflags,
queue->tq_context = context;
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, mtxname, NULL, mtxflags);
return queue;
@ -197,6 +207,7 @@ taskqueue_enqueue_locked(struct taskqueue *queue, struct task *task)
if (task->ta_pending) {
if (task->ta_pending < USHRT_MAX)
task->ta_pending++;
TQ_UNLOCK(queue);
return (0);
}
@ -220,8 +231,12 @@ taskqueue_enqueue_locked(struct taskqueue *queue, struct task *task)
}
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 (0);
}
@ -232,7 +247,6 @@ taskqueue_enqueue(struct taskqueue *queue, struct task *task)
TQ_LOCK(queue);
res = taskqueue_enqueue_locked(queue, task);
TQ_UNLOCK(queue);
return (res);
}
@ -278,8 +292,8 @@ taskqueue_enqueue_timeout(struct taskqueue *queue,
callout_reset(&timeout_task->c, ticks,
taskqueue_timeout_func, timeout_task);
}
TQ_UNLOCK(queue);
}
TQ_UNLOCK(queue);
return (res);
}
@ -566,7 +580,6 @@ taskqueue_thread_enqueue(void *context)
tqp = context;
tq = *tqp;
TQ_ASSERT_LOCKED(tq);
wakeup_one(tq);
}