From: Paul Menage <menage@google.com>
To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: "linux-mm@kvack.org" <linux-mm@kvack.org>,
"lizf@cn.fujitsu.com" <lizf@cn.fujitsu.com>,
"nishimura@mxp.nes.nec.co.jp" <nishimura@mxp.nes.nec.co.jp>,
"balbir@linux.vnet.ibm.com" <balbir@linux.vnet.ibm.com>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>
Subject: Re: [PATCH mmotm 1/2] cgroup: fix to stop adding a new task while rmdir going on
Date: Wed, 10 Dec 2008 14:48:37 -0800 [thread overview]
Message-ID: <6599ad830812101448h46e1ea1cs80635611f9205962@mail.gmail.com> (raw)
In-Reply-To: <20081210133508.3ee454ae.kamezawa.hiroyu@jp.fujitsu.com>
On Tue, Dec 9, 2008 at 8:35 PM, KAMEZAWA Hiroyuki
<kamezawa.hiroyu@jp.fujitsu.com> wrote:
> still need reviews.
> ==
> Recently, pre_destroy() was moved to out of cgroup_lock() for avoiding
> dead lock. But, by this, serialization between task attach and rmdir()
> is lost.
>
> This adds CGRP_TRY_REMOVE flag to cgroup and check it at attaching.
> If attach_pid founds CGRP_TRY_REMOVE, it returns -EBUSY.
As I've mentioned in other threads, I think the fix is to restore the
locking for pre_destroy(), and solve the other potential deadlocks in
better ways.
This patch can result in an attach falsely getting an EBUSY when it
shouldn't really do so (since the cgroup wasn't really going away).
Paul
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next prev parent reply other threads:[~2008-12-10 22:48 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-12-10 4:35 KAMEZAWA Hiroyuki
2008-12-10 4:45 ` [PATCH mmotm 2/2] cgroup: add CSS_POPULATED flag to show css is in use KAMEZAWA Hiroyuki
2008-12-10 22:48 ` Paul Menage [this message]
2008-12-11 0:26 ` [PATCH mmotm 1/2] cgroup: fix to stop adding a new task while rmdir going on KAMEZAWA Hiroyuki
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