From: Li Zefan <lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
To: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Cc: Frederic Weisbecker
<fweisbec-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org,
cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH cgroup/for-3.7-fixes 1/2] Revert "cgroup: Remove task_lock() from cgroup_post_fork()"
Date: Fri, 19 Oct 2012 16:51:02 +0800 [thread overview]
Message-ID: <50811476.1070808@huawei.com> (raw)
In-Reply-To: <20121019005922.GG13370-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
On 2012/10/19 8:59, Tejun Heo wrote:
>>From d935a5d6832a264ce52f4257e176f4f96cbaf048 Mon Sep 17 00:00:00 2001
> From: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
> Date: Thu, 18 Oct 2012 17:40:30 -0700
>
> This reverts commit 7e3aa30ac8c904a706518b725c451bb486daaae9.
>
> The commit incorrectly assumed that fork path always performed
> threadgroup_change_begin/end() and depended on that for
> synchronization against task exit and cgroup migration paths instead
> of explicitly grabbing task_lock().
>
> threadgroup_change is not locked when forking a new process (as
> opposed to a new thread in the same process) and even if it were it
> wouldn't be effective as different processes use different threadgroup
> locks.
>
> Revert the incorrect optimization.
>
> Signed-off-by: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
> LKML-Reference: <20121008020000.GB2575@localhost>
> Cc: Frederic Weisbecker <fweisbec-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> Cc: Li Zefan <lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
> Cc: stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Acked-by: Li Zefan <lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
next prev parent reply other threads:[~2012-10-19 8:51 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-08 2:00 Is not locking task_lock in cgroup_fork() safe? Tejun Heo
2012-10-08 2:01 ` Tejun Heo
2012-10-08 5:46 ` Li Zefan
[not found] ` <507268AA.8050509-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
2012-10-08 6:57 ` Tejun Heo
2012-10-08 6:57 ` Tejun Heo
2012-10-16 19:34 ` Tejun Heo
[not found] ` <20121016193428.GE16166-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-10-17 7:26 ` Li Zefan
2012-10-17 7:26 ` Li Zefan
2012-10-08 5:46 ` Li Zefan
2012-10-08 12:58 ` Frederic Weisbecker
2012-10-08 12:58 ` Frederic Weisbecker
2012-10-08 12:48 ` Frederic Weisbecker
2012-10-08 12:48 ` Frederic Weisbecker
[not found] ` <CAFTL4hzXWtzp7megsCAEuak5=_2SWmp9age-+wrpyQAU4BRZ0w-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-10-16 19:33 ` Tejun Heo
[not found] ` <20121016193341.GD16166-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-10-18 14:50 ` Frederic Weisbecker
2012-10-18 14:50 ` Frederic Weisbecker
[not found] ` <CAFTL4hzo_w7HTgC9ApTk113X8WdZSpV+D+VSEe=604YEJFmKsg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-10-18 20:07 ` Tejun Heo
2012-10-18 20:07 ` Tejun Heo
[not found] ` <20121018200705.GG13370-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-10-18 20:53 ` Frederic Weisbecker
2012-10-18 20:53 ` Frederic Weisbecker
[not found] ` <CAFTL4hy7g4e11OUOyoihrEU8hiVgZoV1=141UtUpj9a72SNs_Q-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-10-19 0:38 ` Tejun Heo
2012-10-19 0:38 ` Tejun Heo
2012-10-19 0:38 ` Tejun Heo
[not found] ` <20121019003835.GE13370-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-10-19 0:58 ` Tejun Heo
2012-10-19 0:58 ` Tejun Heo
[not found] ` <20121019005801.GF13370-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-10-19 8:50 ` Li Zefan
2012-10-19 8:50 ` Li Zefan
2012-10-19 8:50 ` Li Zefan
2012-10-18 14:50 ` Frederic Weisbecker
2012-10-19 0:59 ` [PATCH cgroup/for-3.7-fixes 1/2] Revert "cgroup: Remove task_lock() from cgroup_post_fork()" Tejun Heo
2012-10-19 0:59 ` Tejun Heo
[not found] ` <20121019005922.GG13370-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-10-19 8:51 ` Li Zefan [this message]
2012-10-19 13:35 ` Frederic Weisbecker
2012-10-19 13:35 ` Frederic Weisbecker
[not found] ` <CAFTL4hz82==b3ioSMhbKzh0CN1ivR7RQMKKMFFWu5PHPjg=Bfg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-10-19 19:38 ` Tejun Heo
[not found] ` <20121019193808.GL13370-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-10-19 19:44 ` Frederic Weisbecker
2012-10-19 19:44 ` Frederic Weisbecker
[not found] ` <CAFTL4hwQ6Ntn5GJwj=jiO2p3GdwhEMp0MyR8dgUj_Lx0U4kNqg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-10-19 21:07 ` Tejun Heo
2012-10-19 21:07 ` Tejun Heo
2012-10-19 21:07 ` Tejun Heo
[not found] ` <20121019210738.GA1180-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-10-20 18:21 ` Frederic Weisbecker
2012-10-20 18:21 ` Frederic Weisbecker
[not found] ` <CAFTL4hy+vrvJKrc1Y2FW44k=LBi72H=34337xALpbtG_3u5O7w-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-10-20 18:23 ` Frederic Weisbecker
2012-10-20 18:23 ` Frederic Weisbecker
2012-10-20 22:37 ` Tejun Heo
2012-10-20 22:37 ` Tejun Heo
[not found] ` <20121020223709.GA5626-Gd/HAXX7CRxy/B6EtB590w@public.gmane.org>
2012-10-22 9:30 ` Frederic Weisbecker
2012-10-22 9:30 ` Frederic Weisbecker
2012-10-22 9:30 ` Frederic Weisbecker
2012-10-19 19:44 ` Frederic Weisbecker
2012-10-19 19:38 ` Tejun Heo
2012-10-19 0:59 ` [PATCH cgroup/for-3.7-fixes 2/2] Revert "cgroup: Drop task_lock(parent) on cgroup_fork()" Tejun Heo
2012-10-19 0:59 ` Tejun Heo
[not found] ` <20121019005951.GH13370-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-10-19 8:51 ` Li Zefan
2012-10-19 8:51 ` Li Zefan
2012-10-19 13:45 ` Frederic Weisbecker
2012-10-19 13:45 ` Frederic Weisbecker
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