Commit 21b195c0 authored by Lai Jiangshan's avatar Lai Jiangshan Committed by Tejun Heo
Browse files

workqueue: Remove the mb() pair between wq_worker_sleeping() and insert_work() 



In wq_worker_sleeping(), the access to worklist is protected by the
pool->lock, so the memory barrier is unneeded.

Signed-off-by: default avatarLai Jiangshan <laijs@linux.alibaba.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent daadb3bd

kernel/workqueue.c

+0 −11
Original line number Diff line number Diff line
@@ -918,10 +918,6 @@ void wq_worker_sleeping(struct task_struct *task) 
	}



	/*

	 * The counterpart of the following dec_and_test, implied mb,

	 * worklist not empty test sequence is in insert_work().

	 * Please read comment there.

	 *

	 * NOT_RUNNING is clear.  This means that we're bound to and

	 * running on the local cpu w/ rq lock held and preemption

	 * disabled, which in turn means that none else could be
@@ -1372,13 +1368,6 @@ static void insert_work(struct pool_workqueue *pwq, struct work_struct *work, 
	list_add_tail(&work->entry, head);

	get_pwq(pwq);



	/*

	 * Ensure either wq_worker_sleeping() sees the above

	 * list_add_tail() or we see zero nr_running to avoid workers lying

	 * around lazily while there are works to be processed.

	 */

	smp_mb();



	if (__need_more_worker(pool))

		wake_up_worker(pool);

}