From mboxrd@z Thu Jan  1 00:00:00 1970
From: Glauber Costa <glommer-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
Subject: Re: [PATCH v2 09/11] memcg: propagate kmem limiting information to
 children
Date: Fri, 17 Aug 2012 14:07:00 +0400
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To: Michal Hocko <mhocko-AlSwsSmVLrQ@public.gmane.org>
Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, devel-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org, Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>, Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>, kamezawa.hiroyu-+CUm20s59erQFUHtdCDX3A@public.gmane.org, Christoph Lameter <cl-vYTEC60ixJUAvxtiuMwx3w@public.gmane.org>, David Rientjes <rientjes-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>, Pekka Enberg <penberg-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Pekka Enberg <penberg-bbCR+/B0CizivPeTLB3BmA@public.gmane.org>, Suleiman Souhlal <suleiman-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>

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.