kthread_work: wake up worker only when the worker is idle

If the worker is already executing a work item when another is queued,
we can safely skip wakeup without worrying about stalling queue thus
avoiding waking up the busy worker spuriously.  Spurious wakeups
should be fine but still isn't nice and avoiding it is trivial here.

tj: Updated description.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Lai Jiangshan 2014-07-26 12:03:59 +08:00 committed by Tejun Heo
parent ddcb57e2ed
commit ed1403ec2b
1 changed files with 1 additions and 1 deletions

View File

@ -591,7 +591,7 @@ static void insert_kthread_work(struct kthread_worker *worker,
list_add_tail(&work->node, pos);
work->worker = worker;
if (likely(worker->task))
if (!worker->current_work && likely(worker->task))
wake_up_process(worker->task);
}