From: KAMEZAWA Hiroyuki <kamezawa.hiroyu-+CUm20s59erQFUHtdCDX3A@public.gmane.org>
To: Glauber Costa <glommer-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
Cc: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Li Zefan <lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>,
David Miller <davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>,
devel-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org
Subject: Re: [PATCH v2 3/5] change number_of_cpusets to an atomic
Date: Tue, 24 Apr 2012 11:25:46 +0900 [thread overview]
Message-ID: <4F960F2A.9020304@jp.fujitsu.com> (raw)
In-Reply-To: <1335209867-1831-4-git-send-email-glommer-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
(2012/04/24 4:37), Glauber Costa wrote:
> This will allow us to call destroy() without holding the
> cgroup_mutex(). Other important updates inside update_flags()
> are protected by the callback_mutex.
>
> We could protect this variable with the callback_mutex as well,
> as suggested by Li Zefan, but we need to make sure we are protected
> by that mutex at all times, and some of its updates happen inside the
> cgroup_mutex - which means we would deadlock.
>
> An atomic variable is not expensive, since it is seldom updated,
> and protect us well.
>
> Signed-off-by: Glauber Costa <glommer-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu-+CUm20s59erQFUHtdCDX3A@public.gmane.org>
next prev parent reply other threads:[~2012-04-24 2:25 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-23 19:37 [PATCH v2 0/5] Fix problem with static_key decrement Glauber Costa
2012-04-23 19:37 ` Glauber Costa
[not found] ` <1335209867-1831-1-git-send-email-glommer-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
2012-04-23 19:37 ` [PATCH v2 1/5] don't attach a task to a dead cgroup Glauber Costa
2012-04-23 19:37 ` Glauber Costa
[not found] ` <1335209867-1831-2-git-send-email-glommer-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
2012-04-24 2:20 ` KAMEZAWA Hiroyuki
2012-04-23 19:37 ` [PATCH v2 2/5] blkcg: protect blkcg->policy_list Glauber Costa
2012-04-23 19:37 ` Glauber Costa
2012-04-23 19:37 ` [PATCH v2 3/5] change number_of_cpusets to an atomic Glauber Costa
2012-04-23 19:37 ` Glauber Costa
[not found] ` <1335209867-1831-4-git-send-email-glommer-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
2012-04-24 2:25 ` KAMEZAWA Hiroyuki [this message]
2012-04-24 15:02 ` Christoph Lameter
[not found] ` <alpine.DEB.2.00.1204241001050.26005-sBS69tsa9Uj/9pzu0YdTqQ@public.gmane.org>
2012-04-24 16:15 ` Glauber Costa
2012-04-24 16:15 ` Glauber Costa
[not found] ` <4F96D1A8.6040604-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
2012-04-24 16:24 ` Christoph Lameter
[not found] ` <alpine.DEB.2.00.1204241120130.26005-sBS69tsa9Uj/9pzu0YdTqQ@public.gmane.org>
2012-04-24 16:30 ` Glauber Costa
2012-04-24 16:30 ` Glauber Costa
[not found] ` <4F96D50D.4020804-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
2012-04-24 18:27 ` Christoph Lameter
2012-04-23 19:37 ` [PATCH v2 4/5] don't take cgroup_mutex in destroy() Glauber Costa
2012-04-23 19:37 ` Glauber Costa
[not found] ` <1335209867-1831-5-git-send-email-glommer-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
2012-04-24 2:31 ` KAMEZAWA Hiroyuki
[not found] ` <4F96109A.8000907-+CUm20s59erQFUHtdCDX3A@public.gmane.org>
2012-04-24 11:42 ` Glauber Costa
2012-04-24 11:42 ` Glauber Costa
[not found] ` <4F9691A8.1070106-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
2012-04-25 8:01 ` Li Zefan
2012-04-23 19:37 ` [PATCH v2 5/5] decrement static keys on real destroy time Glauber Costa
2012-04-23 19:37 ` Glauber Costa
[not found] ` <1335209867-1831-6-git-send-email-glommer-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
2012-04-24 2:40 ` KAMEZAWA Hiroyuki
[not found] ` <4F9612B9.7050705-+CUm20s59erQFUHtdCDX3A@public.gmane.org>
2012-04-24 11:41 ` Glauber Costa
2012-04-24 11:41 ` Glauber Costa
2012-04-25 0:22 ` KAMEZAWA Hiroyuki
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