From: Tejun Heo <tj@kernel.org>
To: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH 05/11 V5] workqueue: Add @bind arguement back without change any thing
Date: Thu, 6 Sep 2012 09:51:45 -0700 [thread overview]
Message-ID: <20120906165145.GE29092@google.com> (raw)
In-Reply-To: <5047F686.5010207@cn.fujitsu.com>
Hello, Lai.
On Thu, Sep 06, 2012 at 09:04:06AM +0800, Lai Jiangshan wrote:
> > This doesn't change anything. You're just moving the test to the
> > caller with comments there explaining how it won't change even if
> > gcwq->lock is released. It seems more confusing to me. The flag is
> > still protected by manager_mutex. How is this an improvement?
> >
>
> Some other bit of gcwq->flags is accessed(modified) without manager_mutex.
> making gcwq->flags be accessed only form gcwq->lock C.S. will help the reviewer.
>
> I don't like adding special things/code when not-absolutely-required.
I really fail to see this. The flag has to stay stable while
manage_mutex is held no matter where you test it. It doesn't make any
it any more readable whether you test it inside gcwq->lock with the
comment saying "this won't change while manager_mutex is held" or just
test it while manager_mutex is held. It is a synchronization oddity
no matter what and as long as it's well documented, I don't really see
the point in the change.
Thanks.
--
tejun
next prev parent reply other threads:[~2012-09-06 16:51 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-05 10:37 [PATCH 00/11 V5] workqueue: reimplement unbind/rebind Lai Jiangshan
2012-09-05 10:37 ` [PATCH 01/11 V5] workqueue: ensure the wq_worker_sleeping() see the right flags Lai Jiangshan
2012-09-05 10:37 ` [PATCH 02/11 V5] workqueue: async idle rebinding Lai Jiangshan
2012-09-05 18:06 ` Tejun Heo
2012-09-06 1:28 ` Lai Jiangshan
2012-09-05 10:37 ` [PATCH 03/11 V5] workqueue: new day don't need WORKER_REBIND for busy rebinding Lai Jiangshan
2012-09-05 18:31 ` Tejun Heo
2012-09-06 2:10 ` Lai Jiangshan
2012-09-05 10:37 ` [PATCH 04/11 V5] workqueue: remove WORKER_REBIND Lai Jiangshan
2012-09-05 10:37 ` [PATCH 05/11 V5] workqueue: Add @bind arguement back without change any thing Lai Jiangshan
2012-09-05 19:49 ` Tejun Heo
2012-09-06 1:04 ` Lai Jiangshan
2012-09-06 16:51 ` Tejun Heo [this message]
2012-09-07 2:11 ` Lai Jiangshan
2012-09-07 19:37 ` Tejun Heo
2012-09-05 10:37 ` [PATCH 06/11 V5] workqueue: unbind manager Lai Jiangshan
2012-09-05 10:37 ` [PATCH 07/11 V5] workqueue: rebind manager Lai Jiangshan
2012-09-05 10:37 ` [PATCH 08/11 V5] workqueue: unbind newly created worker Lai Jiangshan
2012-09-05 10:37 ` [PATCH 09/11 V5] workqueue: rebind " Lai Jiangshan
2012-09-05 16:19 ` Lai Jiangshan
2012-09-05 10:37 ` [PATCH 10/11 V5] workqueue: unbind/rebind without manager_mutex Lai Jiangshan
2012-09-05 20:04 ` Tejun Heo
2012-09-06 10:44 ` Lai Jiangshan
2012-09-06 17:00 ` Tejun Heo
2012-09-05 10:37 ` [PATCH 11/11 V5] workqueue: remove manager_mutex Lai Jiangshan
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