From: Lai Jiangshan <laijs@cn.fujitsu.com>
To: Tejun Heo <tj@kernel.org>
Cc: NeilBrown <neilb@suse.de>, Jan Kara <jack@suse.cz>,
Dongsu Park <dongsu.park@profitbricks.com>,
<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH workqueue/for-3.18-fixes 1/2] workqueue: invert the order between pool->lock and wq_mayday_lock
Date: Fri, 5 Dec 2014 10:09:32 +0800 [thread overview]
Message-ID: <548113DC.9040409@cn.fujitsu.com> (raw)
In-Reply-To: <20141204151104.GD15219@htj.dyndns.org>
On 12/04/2014 11:11 PM, Tejun Heo wrote:
> Currently, pool->lock nests inside pool->lock. There's no inherent
> reason for this order. The only place where the two locks are held
> together is pool_mayday_timeout() and it just got decided that way.
>
> This nesting order turns out to complicate things with the planned
> rescuer_thread() update. Let's invert them. This doesn't cause any
> behavior differences.
>
> Signed-off-by: Tejun Heo <tj@kernel.org>
> Cc: NeilBrown <neilb@suse.de>
> Cc: Dongsu Park <dongsu.park@profitbricks.com>
> Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
> ---
> kernel/workqueue.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> --- a/kernel/workqueue.c
> +++ b/kernel/workqueue.c
> @@ -1804,8 +1804,8 @@ static void pool_mayday_timeout(unsigned
> struct worker_pool *pool = (void *)__pool;
> struct work_struct *work;
>
> - spin_lock_irq(&wq_mayday_lock); /* for wq->maydays */
> - spin_lock(&pool->lock);
> + spin_lock_irq(&pool->lock);
> + spin_lock(&wq_mayday_lock); /* for wq->maydays */
>
> if (need_to_create_worker(pool)) {
> /*
> @@ -1818,8 +1818,8 @@ static void pool_mayday_timeout(unsigned
> send_mayday(work);
> }
>
> - spin_unlock(&pool->lock);
> - spin_unlock_irq(&wq_mayday_lock);
> + spin_unlock(&wq_mayday_lock);
> + spin_unlock_irq(&pool->lock);
>
> mod_timer(&pool->mayday_timer, jiffies + MAYDAY_INTERVAL);
> }
>
prev parent reply other threads:[~2014-12-05 2:05 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-29 6:26 [PATCH/RFC] workqueue: allow rescuer thread to do more work NeilBrown
2014-10-29 14:32 ` Tejun Heo
2014-10-29 23:19 ` NeilBrown
2014-11-04 14:22 ` Tejun Heo
2014-11-06 16:58 ` Dongsu Park
2014-11-07 3:03 ` Lai Jiangshan
2014-11-10 5:28 ` NeilBrown
2014-11-10 8:52 ` Jan Kara
2014-11-10 22:04 ` NeilBrown
2014-11-14 17:21 ` Tejun Heo
2014-11-18 4:27 ` [PATCH - v3?] " NeilBrown
2014-11-18 6:01 ` Lai Jiangshan
2014-11-18 6:11 ` NeilBrown
2014-12-02 20:43 ` Tejun Heo
2014-12-03 0:40 ` NeilBrown
2014-12-03 17:20 ` Tejun Heo
2014-12-03 18:02 ` Tejun Heo
2014-12-03 22:31 ` Dongsu Park
2014-12-04 1:19 ` NeilBrown
2014-12-04 1:01 ` Lai Jiangshan
2014-12-04 14:57 ` Tejun Heo
2014-12-04 15:11 ` [PATCH workqueue/for-3.18-fixes 1/2] workqueue: invert the order between pool->lock and wq_mayday_lock Tejun Heo
2014-12-04 15:12 ` [PATCH workqueue/for-3.18-fixes 2/2] workqueue: allow rescuer thread to do more work Tejun Heo
2014-12-08 17:40 ` Tejun Heo
2014-12-08 22:47 ` NeilBrown
2014-12-05 2:09 ` Lai Jiangshan [this message]
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