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From: Li Zefan <lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
To: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Cc: cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH v2 cgroup/for-3.15-fixes 1/2] cgroup: introduce task_css_is_root()
Date: Thu, 8 May 2014 09:22:29 +0800	[thread overview]
Message-ID: <536ADC55.6080105@huawei.com> (raw)
In-Reply-To: <20140507130627.GA16702-Gd/HAXX7CRxy/B6EtB590w@public.gmane.org>

于 2014/5/7 21:06, Tejun Heo 写道:
> Determining the css of a task usually requires RCU read lock as that's
> the only thing which keeps the returned css accessible till its
> reference is acquired; however, testing whether a task belongs to the
> root can be performed without dereferencing the returned css by
> comparing the returned pointer against the root one in init_css_set[]
> which never changes.
> 
> Implement task_css_is_root() which can be invoked in any context.
> This will be used by the scheduled cgroup_freezer change.
> 
> v2: cgroup no longer supports modular controllers.  No need to export
>     init_css_set.  Pointed out by Li.
> 
> Signed-off-by: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>

Acked-by: Li Zefan <lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>

  parent reply	other threads:[~2014-05-08  1:22 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-05-05 22:35 [PATCH cgroup/for-3.15-fixes 1/2] cgroup: introduce task_css_is_root() Tejun Heo
     [not found] ` <20140505223557.GU11231-Gd/HAXX7CRxy/B6EtB590w@public.gmane.org>
2014-05-05 22:39   ` [PATCH cgroup/for-3.15-fixes 2/2] cgroup_freezer: replace freezer->lock with freezer_mutex Tejun Heo
     [not found]     ` <20140505223941.GV11231-Gd/HAXX7CRxy/B6EtB590w@public.gmane.org>
2014-05-08  1:23       ` Li Zefan
2014-05-07  2:50   ` [PATCH cgroup/for-3.15-fixes 1/2] cgroup: introduce task_css_is_root() Li Zefan
     [not found]     ` <53699F6E.3070107-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
2014-05-07  3:29       ` Tejun Heo
2014-05-07 13:06   ` [PATCH v2 " Tejun Heo
     [not found]     ` <20140507130627.GA16702-Gd/HAXX7CRxy/B6EtB590w@public.gmane.org>
2014-05-08  1:22       ` Li Zefan [this message]
2014-05-08  1:32       ` Tejun Heo
     [not found]         ` <20140508013206.GA2797-Gd/HAXX7CRxy/B6EtB590w@public.gmane.org>
2014-05-13 15:35           ` Tejun Heo

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