From mboxrd@z Thu Jan  1 00:00:00 1970
From: Glauber Costa <glommer@gmail.com>
Subject: Re: [PATCH v3 5/9] memcg: use css_get/put when charging/uncharging
 kmem
Date: Fri, 14 Jun 2013 14:56:13 +0400
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To: Li Zefan <lizefan@huawei.com>
Cc: Michal Hocko <mhocko@suse.cz>, Tejun Heo <tj@kernel.org>, Glauber Costa <glommer@openvz.org>, Johannes Weiner <hannes@cmpxchg.org>, LKML <linux-kernel@vger.kernel.org>, cgroups <cgroups@vger.kernel.org>, linux-mm@kvack.org, KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

On Fri, Jun 14, 2013 at 09:17:40AM +0800, Li Zefan wrote:
> >>  static void memcg_kmem_mark_dead(struct mem_cgroup *memcg)
> >>  {
> >> +	/*
> >> +	 * We need to call css_get() first, because memcg_uncharge_kmem()
> >> +	 * will call css_put() if it sees the memcg is dead.
> >> +	 */
> >> +	smb_wmb();
> >>  	if (test_bit(KMEM_ACCOUNTED_ACTIVE, &memcg->kmem_account_flags))
> >>  		set_bit(KMEM_ACCOUNTED_DEAD, &memcg->kmem_account_flags);
> > 
> > I do not feel strongly about that but maybe open coding this in
> > mem_cgroup_css_offline would be even better. There is only single caller
> > and there is smaller chance somebody will use the function incorrectly
> > later on.
> > 
> > So I leave the decision on you because this doesn't matter much.
> > 
> 
> Yeah, it should go away soon. I'll post a patch after this patchset gets
> merged into -mm tree and then we can discuss there.
 
I don't care if it is open coded or not. If there is any strong preference
from anyone on this matter, feel free to change it.

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