From: Benjamin LaHaise <bcrl@kvack.org>
To: Gu Zheng <guz.fnst@cn.fujitsu.com>
Cc: Dave Jones <davej@redhat.com>, Al Viro <viro@zeniv.linux.org.uk>,
jmoyer@redhat.com, kosaki.motohiro@jp.fujitsu.com,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>,
tangchen <tangchen@cn.fujitsu.com>,
miaox@cn.fujitsu.com, linux-aio@kvack.org,
fsdevel <linux-fsdevel@vger.kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 2/2] aio: fix the confliction of read events and migrating ring page
Date: Fri, 21 Mar 2014 13:35:19 -0400 [thread overview]
Message-ID: <20140321173519.GB23173@kvack.org> (raw)
In-Reply-To: <532B9C54.80705@cn.fujitsu.com>
Hi Gu,
On Fri, Mar 21, 2014 at 09:56:36AM +0800, Gu Zheng wrote:
> This one is based on linux-next which has merged the following patch:
> commit 692c9b8c5ee8d263bb8348171f0bebd3d84eb2c1
> Author: Tang Chen <tangchen@cn.fujitsu.com>
> Date: Mon Mar 10 16:15:33 2014 +0800
> aio, memory-hotplug: Fix confliction when migrating and accessing ring pages.
>
> With this patch, the update of the ring's head pointer is safe because it is protected
> by completion_lock, so we do not need to enlarge the ring_lock protection region.
> And on the other side, if we take the ring_lock over the entire page migration
> operation, reading events will be affected if the page migration is going.
I have dropped this particular change of Tang's from my aio-next tree.
The spinlock addition in the read events code path is not needed if we
take the ring_lock mutex in the page migration code path. This will
ensure that we aren't needlessly regressing performance. I'll send out
my replacement patch in a couple of minutes.
-ben
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next prev parent reply other threads:[~2014-03-21 17:35 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-20 5:46 [PATCH 2/2] aio: fix the confliction of read events and migrating ring page Gu Zheng
2014-03-20 14:32 ` Dave Jones
2014-03-20 16:30 ` Benjamin LaHaise
2014-03-21 1:56 ` Gu Zheng
2014-03-21 17:35 ` Benjamin LaHaise [this message]
2014-03-21 18:35 ` [PATCH] aio: ensure access to ctx->ring_pages is correctly serialised Benjamin LaHaise
2014-03-24 10:56 ` Gu Zheng
2014-03-24 10:59 ` [V2 PATCH 1/2] aio: clean up aio_migratepage() and related code much Gu Zheng
2014-03-24 13:20 ` Benjamin LaHaise
2014-03-25 10:11 ` Gu Zheng
2014-03-24 10:59 ` [V2 PATCH 2/2] aio: fix the confliction of aio read events and aio migrate page Gu Zheng
2014-03-24 18:22 ` [PATCH] aio: ensure access to ctx->ring_pages is correctly serialised Sasha Levin
2014-03-24 19:07 ` Benjamin LaHaise
2014-03-25 17:47 ` Sasha Levin
2014-03-25 18:57 ` Benjamin LaHaise
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