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Date: Mon, 15 Mar 2010 11:00:25 +0100
From: Andrea Righi <arighi@develer.com>
To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>,
       Balbir Singh <balbir@linux.vnet.ibm.com>,
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       Greg Thelen <gthelen@google.com>,
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       Andrew Morton <akpm@linux-foundation.org>,
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       linux-mm@kvack.org
Subject: Re: [PATCH -mmotm 1/5] memcg: disable irq at page cgroup lock
Message-ID: <20100315100024.GA1653@linux.develer.com>
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 <20100315090638.ee416d93.kamezawa.hiroyu@jp.fujitsu.com>
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On Mon, Mar 15, 2010 at 09:06:38AM +0900, KAMEZAWA Hiroyuki wrote:
> On Mon, 15 Mar 2010 00:26:38 +0100
> Andrea Righi <arighi@develer.com> wrote:
> 
> > From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> > 
> > Now, file-mapped is maintaiend. But more generic update function
> > will be needed for dirty page accounting.
> > 
> > For accountig page status, we have to guarantee lock_page_cgroup()
> > will be never called under tree_lock held.
> > To guarantee that, we use trylock at updating status.
> > By this, we do fuzzy accounting, but in almost all case, it's correct.
> > 
> > Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> 
> Bad patch title...."use trylock for safe accounting in some contexts" ?

OK, sounds better. I just copy & paste the email subject, but the title
was probably related to the old lock_page_cgroup()+irq_disable patch.

Thanks,
-Andrea