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Subject[PATCH] workqueue: kick a worker in pwq_adjust_max_active()
From 951a078a5285ad31bc22e190616ad54b78fac992 Mon Sep 17 00:00:00 2001
From: Lai Jiangshan <laijs@cn.fujitsu.com>
Date: Wed, 20 Mar 2013 10:52:30 -0700

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>
---
kernel/workqueue.c | 13 ++++++-------
1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index d2ac6cb..79d1d34 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -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);
--
1.8.1.4


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