From: Balbir Singh <balbir@linux.vnet.ibm.com>
To: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: LKML <linux-kernel@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>,
Andrew Morton <akpm@linux-foundation.org>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Pavel Emelyanov <xemul@openvz.org>,
Li Zefan <lizf@cn.fujitsu.com>, Paul Menage <menage@google.com>
Subject: Re: [RFC][PATCH 5/4] memcg: don't call res_counter_uncharge when obsolete
Date: Wed, 14 Jan 2009 19:25:39 +0530 [thread overview]
Message-ID: <20090114135539.GA21516@balbir.in.ibm.com> (raw)
In-Reply-To: <20090114175121.275ecd59.nishimura@mxp.nes.nec.co.jp>
* Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> [2009-01-14 17:51:21]:
> This is a new one. Please review.
>
> ===
> From: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
>
> mem_cgroup_get ensures that the memcg that has been got can be accessed
> even after the directory has been removed, but it doesn't ensure that parents
> of it can be accessed: parents might have been freed already by rmdir.
>
> This causes a bug in case of use_hierarchy==1, because res_counter_uncharge
> climb up the tree.
>
> Check if the memcg is obsolete, and don't call res_counter_uncharge when obsole.
>
> Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
I liked the earlier, EBUSY approach that ensured that parents could
not go away if children exist. IMHO, the code has gotten too complex
and has too many corner cases. Time to revisit it.
--
Balbir
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next prev parent reply other threads:[~2009-01-14 13:57 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-01-13 9:45 [PATCH -rc] some fixes for memcg Daisuke Nishimura
2009-01-13 9:47 ` [PATCH 1/4] memcg: fix mem_cgroup_get_reclaim_stat_from_page Daisuke Nishimura
2009-01-13 9:48 ` [PATCH 2/4] memcg: fix error path of mem_cgroup_move_parent Daisuke Nishimura
2009-01-13 9:49 ` [PATCH 3/4] memcg: fix hierarchical reclaim Daisuke Nishimura
2009-01-13 9:50 ` [PATCH 4/4] memcg: make oom less frequently Daisuke Nishimura
2009-01-14 8:51 ` [RFC][PATCH 5/4] memcg: don't call res_counter_uncharge when obsolete Daisuke Nishimura
2009-01-14 13:43 ` KAMEZAWA Hiroyuki
2009-01-15 1:03 ` Daisuke Nishimura
2009-01-15 2:00 ` KAMEZAWA Hiroyuki
2009-01-15 2:14 ` Daisuke Nishimura
2009-01-15 4:38 ` Daisuke Nishimura
2009-01-15 5:14 ` KAMEZAWA Hiroyuki
2009-01-15 5:49 ` Balbir Singh
2009-01-15 6:39 ` KAMEZAWA Hiroyuki
2009-01-15 7:45 ` [RFC][PATCH] memcg: get/put parents at create/free Daisuke Nishimura
2009-01-15 7:54 ` KAMEZAWA Hiroyuki
2009-01-15 8:13 ` Daisuke Nishimura
2009-01-15 8:23 ` KAMEZAWA Hiroyuki
2009-01-15 8:51 ` Daisuke Nishimura
2009-01-15 9:10 ` KAMEZAWA Hiroyuki
2009-01-16 1:50 ` [BUGFIX][PATCH] " Daisuke Nishimura
2009-01-16 2:12 ` Andrew Morton
2009-01-16 2:17 ` KAMEZAWA Hiroyuki
2009-01-16 2:25 ` Daisuke Nishimura
2009-01-16 4:22 ` Daisuke Nishimura
2009-01-16 4:31 ` KAMEZAWA Hiroyuki
2009-01-14 13:55 ` Balbir Singh [this message]
2009-01-15 2:48 ` [RFC][PATCH 5/4] memcg: don't call res_counter_uncharge when obsolete KAMEZAWA Hiroyuki
2009-01-15 3:08 ` KAMEZAWA Hiroyuki
2009-01-15 3:24 ` KAMEZAWA Hiroyuki
2009-01-15 4:17 ` Balbir Singh
2009-01-15 4:41 ` KAMEZAWA Hiroyuki
2009-01-15 4:45 ` Balbir Singh
2009-01-15 4:54 ` KAMEZAWA Hiroyuki
2009-01-15 4:52 ` KAMEZAWA Hiroyuki
2009-01-15 5:17 ` Balbir Singh
2009-01-15 5:27 ` KAMEZAWA Hiroyuki
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