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From: Hiroyuki Kamezawa <kamezawa.hiroyuki@gmail.com>
To: balbir@linux.vnet.ibm.com
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	"nishimura@mxp.nes.nec.co.jp" <nishimura@mxp.nes.nec.co.jp>,
	gthelen@google.com,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
	stable@kernel.org
Subject: Re: [BUGFIX][PATCH] memcg: fix race in file_mapped accouting flag management
Date: Tue, 14 Sep 2010 00:28:30 +0900	[thread overview]
Message-ID: <AANLkTimsUQuEeS2QvSwY_WhnQY7n=D73fNmOoqgrTqbZ@mail.gmail.com> (raw)
In-Reply-To: <20100913084741.GD17950@balbir.in.ibm.com>

2010/9/13 Balbir Singh <balbir@linux.vnet.ibm.com>:
> * KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> [2010-09-13 16:08:22]:
>
>>
>> I think this small race is not very critical but it's bug.
>> We have this race since 2.6.34.
>> =
>> From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
>>
>> Now. memory cgroup accounts file-mapped by counter and flag.
>> counter is working in the same way with zone_stat but FileMapped flag only
>> exists in memcg (for helping move_account).
>>
>> This flag can be updated wrongly in a case. Assume CPU0 and CPU1
>> and a thread mapping a page on CPU0, another thread unmapping it on CPU1

  reply	other threads:[~2010-09-13 15:29 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-09-13  7:08 KAMEZAWA Hiroyuki
2010-09-13  7:13 ` [PATCH] " KAMEZAWA Hiroyuki
2010-09-13  8:01   ` [PATCH] memcg: avoid lock in updating file_mapped (Was " KAMEZAWA Hiroyuki
2010-09-13 17:26     ` Balbir Singh
2010-09-14  4:55       ` KAMEZAWA Hiroyuki
2010-09-13  8:47 ` [BUGFIX][PATCH] memcg: " Balbir Singh
2010-09-13 15:28   ` Hiroyuki Kamezawa [this message]
2010-09-13 17:17     ` Balbir Singh
2010-09-13 21:08 ` Andrew Morton
2010-09-14  4:35   ` KAMEZAWA Hiroyuki
2010-09-14  4:38   ` KAMEZAWA Hiroyuki

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