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From: Tejun Heo <tj@kernel.org>
To: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH 02/10 V4] workqueue: fix deadlock in rebind_workers()
Date: Tue, 4 Sep 2012 18:33:47 -0700	[thread overview]
Message-ID: <20120905013347.GF2836@dhcp-172-17-108-109.mtv.corp.google.com> (raw)
In-Reply-To: <5046AAC6.7010704@cn.fujitsu.com>

Hello,

On Wed, Sep 05, 2012 at 09:28:38AM +0800, Lai Jiangshan wrote:
> I see that this patch's idea is same as mine but reuses
> @idle_rebind.cnt and @idle_rebind.done.
> 
> I don't think it is consistent to avoid adding new field
> and to reuse old field for different purpose

It's not necessarily the reuse which seems more consistent to me but
where the driving logic is.  It's now better contained in
rebind_workers().

> > -	/*
> > -	 * All idle workers are rebound and waiting for %WORKER_REBIND to
> > -	 * be cleared inside idle_worker_rebind().  Clear and release.
> > -	 * Clearing %WORKER_REBIND from this foreign context is safe
> > -	 * because these workers are still guaranteed to be idle.
> > -	 */
> > -	for_each_worker_pool(pool, gcwq)
> > -		list_for_each_entry(worker, &pool->idle_list, entry)
> > -			worker->flags &= ~WORKER_REBIND;
> > -
> > -	wake_up_all(&gcwq->rebind_hold);
> 
> don't need to move down.

Yeap, but cleaner that way.  With the moving separated into another
patch, the addition of another handshake stage becomes easier to
follow.

Thanks.

-- 
tejun

  reply	other threads:[~2012-09-05  1:33 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-09-01 16:28 [PATCH 00/10 V4] workqueue: fix and cleanup hotplug/rebind_workers() Lai Jiangshan
2012-09-01 16:28 ` [PATCH 01/10 V4] workqueue: ensure the wq_worker_sleeping() see the right flags Lai Jiangshan
2012-09-04 23:39   ` [PATCH] workqueue: UNBOUND -> REBIND morphing in rebind_workers() should be atomic Tejun Heo
2012-09-04 23:58     ` [PATCH -stable] " Tejun Heo
2012-09-16 15:49       ` Ben Hutchings
2012-09-05  1:05     ` [PATCH] " Lai Jiangshan
2012-09-05  1:17       ` Tejun Heo
2012-09-01 16:28 ` [PATCH 02/10 V4] workqueue: fix deadlock in rebind_workers() Lai Jiangshan
2012-09-05  0:54   ` Tejun Heo
2012-09-05  1:28     ` Lai Jiangshan
2012-09-05  1:33       ` Tejun Heo [this message]
2012-09-01 16:28 ` [PATCH 03/10 V4] workqueue: add POOL_MANAGING_WORKERS Lai Jiangshan
2012-09-01 16:28 ` [PATCH 04/10 V4] workqueue: add manage_workers_slowpath() Lai Jiangshan
2012-09-05  1:12   ` Tejun Heo
2012-09-06  1:55     ` Lai Jiangshan
2012-09-01 16:28 ` [PATCH 05/10 V4] workqueue: move rebind_hold to idle_rebind Lai Jiangshan
2012-09-01 16:28 ` [PATCH 06/10 V4] workqueue: simple clear WORKER_REBIND Lai Jiangshan
2012-09-01 16:28 ` [PATCH 07/10 V4] workqueue: move idle_rebind pointer to gcwq Lai Jiangshan
2012-09-01 16:28 ` [PATCH 08/10 V4] workqueue: explicit way to wait for idles workers to finish Lai Jiangshan
2012-09-01 16:28 ` [PATCH 09/10] workqueue: single pass rebind_workers Lai Jiangshan
2012-09-01 16:28 ` [PATCH 10/10 V4] workqueue: merge the role of rebind_hold to idle_done Lai Jiangshan
2012-09-05  1:15   ` Tejun Heo
2012-09-05  1:48     ` Lai Jiangshan

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