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workqueue: remove an unneeded UNBOUND test before waking up the next worker

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In process_one_work():

	if ((worker->flags & WORKER_UNBOUND) && need_more_worker(pool))
		wake_up_worker(pool);

the first test is unneeded.  Even if the first test is removed, it
doesn't affect the wake-up logic for WORKER_UNBOUND, and it will not
introduce any useless wake-ups for normal per-cpu workers since
nr_running is always >= 1.  It will introduce useless/redundant
wake-ups for CPU_INTENSIVE, but this case is rare and the next patch
will also remove this redundant wake-up.

tj: Minor updates to the description and comment.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Lai Jiangshan 2014-07-22 13:01:59 +08:00 committed by Tejun Heo
parent d8ca83e68c
commit a489a03eca
1 changed files with 6 additions and 3 deletions
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9
kernel/workqueue.c
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@ -2048,10 +2048,13 @@ __acquires(&pool->lock)
worker_set_flags(worker, WORKER_CPU_INTENSIVE, true); worker_set_flags(worker, WORKER_CPU_INTENSIVE, true);
/* /*
* Unbound pool isn't concurrency managed and work items should be * Wake up another worker if necessary. The condition is always
* executed ASAP. Wake up another worker if necessary. * false for normal per-cpu workers since nr_running would always
* be >= 1 at this point. This is used to chain execution of the
* pending work items for WORKER_NOT_RUNNING workers such as the
* UNBOUND ones.
*/ */
if ((worker->flags & WORKER_UNBOUND) && need_more_worker(pool)) if (need_more_worker(pool))
wake_up_worker(pool); wake_up_worker(pool);
/* /*