Commit 951a078a authored Mar 20, 2013 by Lai Jiangshan Committed by Tejun Heo Mar 20, 2013

workqueue: kick a worker in pwq_adjust_max_active()



If pwq_adjust_max_active() changes max_active from 0 to
saved_max_active, it needs to wakeup worker.  This is already done by
thaw_workqueues().

If pwq_adjust_max_active() increases max_active for an unbound wq,
while not strictly necessary for correctness, it's still desirable to
wake up a worker so that the requested concurrency level is reached
sooner.

Move wake_up_worker() call from thaw_workqueues() to
pwq_adjust_max_active() so that it can handle both of the above two
cases.  This also makes thaw_workqueues() simpler.

tj: Updated comments and description.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

parent 6a092dfd

kernel/workqueue.c

+6 −7

Original line number	Diff line number	Diff line
		@@ -3598,6 +3598,12 @@ static void pwq_adjust_max_active(struct pool_workqueue *pwq)
		while (!list_empty(&pwq->delayed_works) &&
		pwq->nr_active < pwq->max_active)
		pwq_activate_first_delayed(pwq);

		/*
		* Need to kick a worker after thawed or an unbound wq's
		* max_active is bumped. It's a slow path. Do it always.
		*/
		wake_up_worker(pwq->pool);
		} else {
		pwq->max_active = 0;
		}
		@@ -4401,13 +4407,6 @@ void thaw_workqueues(void)
		}
		spin_unlock_irq(&pwq_lock);

		/* kick workers */
		for_each_pool(pool, pi) {
		spin_lock_irq(&pool->lock);
		wake_up_worker(pool);
		spin_unlock_irq(&pool->lock);
		}

		workqueue_freezing = false;
		out_unlock:
		mutex_unlock(&wq_mutex);

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