From: "KAMEZAWA Hiroyuki" <kamezawa.hiroyu@jp.fujitsu.com>
To: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
kamezawa.hiroyu@jp.fujitsu.com, balbir@linux.vnet.ibm.com,
lizf@cn.fujitsu.com, menage@google.com
Subject: Re: [RFC][PATCH 2/4] memcg: fix error path of mem_cgroup_move_parent
Date: Thu, 8 Jan 2009 20:00:46 +0900 (JST) [thread overview]
Message-ID: <37143.10.75.179.62.1231412446.squirrel@webmail-b.css.fujitsu.com> (raw)
In-Reply-To: <20090108191445.cd860c37.nishimura@mxp.nes.nec.co.jp>
Daisuke Nishimura said:
> There is a bug in error path of mem_cgroup_move_parent.
>
> Extra refcnt got from try_charge should be dropped, and usages incremented
> by try_charge should be decremented in both error paths:
>
> A: failure at get_page_unless_zero
> B: failure at isolate_lru_page
>
> This bug makes this parent directory unremovable.
>
> In case of A, rmdir doesn't return, because res.usage doesn't go
> down to 0 at mem_cgroup_force_empty even after all the pc in
> lru are removed.
> In case of B, rmdir fails and returns -EBUSY, because it has
> extra ref counts even after res.usage goes down to 0.
>
>
> Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Thank you for catching.
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
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next prev parent reply other threads:[~2009-01-08 11:00 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-01-08 10:08 [RFC][PATCH 0/4] some memcg fixes Daisuke Nishimura
2009-01-08 10:14 ` [RFC][PATCH 1/4] memcg: fix for mem_cgroup_get_reclaim_stat_from_page Daisuke Nishimura
2009-01-08 10:59 ` [RFC][PATCH 1/4] memcg: fix formem_cgroup_get_reclaim_stat_from_page KAMEZAWA Hiroyuki
2009-01-09 0:57 ` [RFC][PATCH 1/4] memcg: fix for mem_cgroup_get_reclaim_stat_from_page Li Zefan
2009-01-09 1:05 ` KAMEZAWA Hiroyuki
2009-01-09 2:34 ` Daisuke Nishimura
2009-01-09 2:41 ` KAMEZAWA Hiroyuki
2009-01-09 4:32 ` Balbir Singh
2009-01-09 4:47 ` KAMEZAWA Hiroyuki
2009-01-15 11:08 ` [PATCH] mark_page_accessed() in do_swap_page() move latter than memcg charge KOSAKI Motohiro
2009-01-15 11:12 ` KAMEZAWA Hiroyuki
2009-01-15 11:30 ` Balbir Singh
2009-01-15 12:07 ` Hugh Dickins
2009-01-15 12:28 ` KAMEZAWA Hiroyuki
2009-01-15 13:34 ` KOSAKI Motohiro
2009-01-15 13:43 ` KOSAKI Motohiro
2009-01-08 10:14 ` [RFC][PATCH 2/4] memcg: fix error path of mem_cgroup_move_parent Daisuke Nishimura
2009-01-08 11:00 ` KAMEZAWA Hiroyuki [this message]
2009-01-09 5:15 ` Balbir Singh
2009-01-09 5:33 ` Daisuke Nishimura
2009-01-09 6:01 ` Balbir Singh
2009-01-08 10:15 ` [RFC][PATCH 3/4] memcg: fix for mem_cgroup_hierarchical_reclaim Daisuke Nishimura
2009-01-08 11:08 ` KAMEZAWA Hiroyuki
2009-01-09 1:08 ` KAMEZAWA Hiroyuki
2009-01-09 2:51 ` Daisuke Nishimura
2009-01-09 3:09 ` KAMEZAWA Hiroyuki
2009-01-09 5:34 ` Balbir Singh
2009-01-09 5:33 ` Balbir Singh
2009-01-09 6:01 ` Daisuke Nishimura
2009-01-09 9:01 ` Daisuke Nishimura
2009-01-08 10:15 ` [RFC][PATCH 4/4] memcg: make oom less frequently Daisuke Nishimura
2009-01-08 11:19 ` KAMEZAWA Hiroyuki
2009-01-09 1:44 ` Daisuke Nishimura
2009-01-09 2:03 ` KAMEZAWA Hiroyuki
2009-01-09 2:29 ` Daisuke Nishimura
2009-01-09 2:39 ` KAMEZAWA Hiroyuki
2009-01-09 5:58 ` Balbir Singh
2009-01-09 8:52 ` Daisuke Nishimura
2009-01-09 9:03 ` Balbir Singh
2009-01-09 9:37 ` KAMEZAWA Hiroyuki
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