Message-ID: <502E17C4.7060204@parallels.com>
Date: Fri, 17 Aug 2012 14:07:00 +0400
From: Glauber Costa <glommer@parallels.com>
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To: Michal Hocko <mhocko@suse.cz>
CC: <linux-kernel@vger.kernel.org>, <linux-mm@kvack.org>,
        <cgroups@vger.kernel.org>, <devel@openvz.org>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        <kamezawa.hiroyu@jp.fujitsu.com>, Christoph Lameter <cl@linux.com>,
        "David Rientjes" <rientjes@google.com>,
        Pekka Enberg <penberg@kernel.org>,
        "Pekka Enberg" <penberg@cs.helsinki.fi>,
        Suleiman Souhlal <suleiman@google.com>
Subject: Re: [PATCH v2 09/11] memcg: propagate kmem limiting information to
 children
References: <1344517279-30646-1-git-send-email-glommer@parallels.com> <1344517279-30646-10-git-send-email-glommer@parallels.com> <20120817090005.GC18600@dhcp22.suse.cz> <502E0BC3.8090204@parallels.com> <20120817093504.GE18600@dhcp22.suse.cz>
In-Reply-To: <20120817093504.GE18600@dhcp22.suse.cz>
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On 08/17/2012 01:35 PM, Michal Hocko wrote:
>>> Above you said "Once enabled, can't be disabled." and now you can
>>> > > disable it? Say you are a leaf group with non accounted parents. This
>>> > > will clear the flag and so no further accounting is done. Shouldn't
>>> > > unlimited mean that we will never reach the limit? Or am I missing
>>> > > something?
>>> > >
>> > 
>> > You are missing something, and maybe I should be more clear about that.
>> > The static branches can't be disabled (it is only safe to disable them
>> > from disarm_static_branches(), when all references are gone). Note that
>> > when unlimited, we flip bits, do a transversal, but there is no mention
>> > to the static branch.
> My little brain still doesn't get this. I wasn't concerned about static
> branches. I was worried about memcg_can_account_kmem which will return
> false now, doesn't it.
> 

Yes, it will. If I got you right, you are concerned because I said that
can't happen. But it will.

But I never said that can't happen. I said (ok, I meant) the static
branches can't be disabled.

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