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From: Paul Menage <menage@google.com>
To: Li Zefan <lizf@cn.fujitsu.com>
Cc: Colin Cross <ccross@android.com>,
	linux-kernel@vger.kernel.org,
	containers@lists.linux-foundation.org
Subject: Re: [PATCH] cgroup: Convert synchronize_rcu to call_rcu in cgroup_attach_task
Date: Wed, 24 Nov 2010 10:58:23 -0800	[thread overview]
Message-ID: <AANLkTikhE-z7HuLimuj_pJLKd7FHq+w6PQCd85XuT0a8@mail.gmail.com> (raw)
In-Reply-To: <4CEC7329.7070909@cn.fujitsu.com>

On Tue, Nov 23, 2010 at 6:06 PM, Li Zefan <lizf@cn.fujitsu.com> wrote:
>
> If we do this, it's not anymore safe to use get_css_set(), which just
> increments the refcount without checking if it's zero.

I don't believe that it's currently safe to use get_css_set() on a
zero-refcount css_set anyway - a css_set starts with refcount 1 and
can be freed the moment that its refcount reaches 0. You can only use
get_css_set() on a stable reference to an existing css_set, which by
definition has a refcount of at least 1. Were you thinking of any
particular existing uses?

Paul

      parent reply	other threads:[~2010-11-24 18:58 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-11-21  2:00 [PATCH] cgroup: Remove RCU from task->cgroups Colin Cross
2010-11-21 23:02 ` Colin Cross
2010-11-22  4:06   ` [PATCH] cgroup: Convert synchronize_rcu to call_rcu in cgroup_attach_task Colin Cross
2010-11-23  8:14     ` Li Zefan
2010-11-23  8:58       ` Colin Cross
2010-11-23 20:22         ` Colin Cross
2010-11-24  1:24     ` Paul Menage
2010-11-24  1:43       ` [PATCH] cgroup: Remove call to synchronize_rcu " Colin Cross
2010-11-24  2:29         ` Colin Cross
2011-01-22  1:17         ` Bryan Huntsman
2011-01-22  2:04           ` Colin Cross
2011-01-28  1:17         ` Bryan Huntsman
2010-11-24  2:06       ` [PATCH] cgroup: Convert synchronize_rcu to call_rcu " Li Zefan
2010-11-24  2:10         ` Colin Cross
2010-11-24  5:37           ` [PATCH 1/2] cgroup: Set CGRP_RELEASABLE when adding to a cgroup Colin Cross
2010-11-24 23:54             ` Paul Menage
2010-11-25  0:11               ` Colin Cross
2010-11-25  0:18                 ` Colin Cross
2010-11-25  0:21                 ` Paul Menage
2010-12-03  3:07                   ` Colin Cross
2010-12-17  0:54                     ` Paul Menage
2010-12-17  1:12                       ` Colin Cross
2011-01-28  1:17             ` Bryan Huntsman
2011-01-28  1:30               ` Paul Menage
2011-01-28  1:48                 ` Michael Bohan
2010-11-24  5:37           ` [PATCH 2/2] cgroup: Remove call to synchronize_rcu in cgroup_attach_task Colin Cross
2011-01-28  1:17             ` Bryan Huntsman
2010-11-24 18:58         ` Paul Menage [this message]

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