Message-ID: <4FC52612.5060006@parallels.com>
Date: Tue, 29 May 2012 23:40:02 +0400
From: Glauber Costa <glommer@parallels.com>
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To: Christoph Lameter <cl@linux.com>
CC: <linux-kernel@vger.kernel.org>, <cgroups@vger.kernel.org>,
        <linux-mm@kvack.org>, <kamezawa.hiroyu@jp.fujitsu.com>,
        Tejun Heo <tj@kernel.org>, Li Zefan <lizefan@huawei.com>,
        Greg Thelen <gthelen@google.com>,
        Suleiman Souhlal <suleiman@google.com>, Michal Hocko <mhocko@suse.cz>,
        Johannes Weiner <hannes@cmpxchg.org>, <devel@openvz.org>,
        David Rientjes <rientjes@google.com>,
        Pekka Enberg <penberg@cs.helsinki.fi>
Subject: Re: [PATCH v3 13/28] slub: create duplicate cache
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On 05/29/2012 11:26 PM, Christoph Lameter wrote:
> On Tue, 29 May 2012, Glauber Costa wrote:
>
>> But we really need a page to be filled with objects from the same cgroup, and
>> the non-shared objects to be accounted to the right place.
>
> No other subsystem has such a requirement. Even the NUMA nodes are mostly
> suggestions and can be ignored by the allocators to use memory from other
> pages.

Of course it does. Memcg itself has such a requirement. The collective 
set of processes needs to have the pages it uses accounted to it, and 
never go over limit.

>> Otherwise, I don't think we can meet even the lighter of isolation guarantees.
>
> The approach works just fine with NUMA and cpusets. Isolation is mostly
> done on the per node boundaries and you already have per node statistics.

I don't know about cpusets in details, but at least with NUMA, this is 
not an apple-to-apple comparison. a NUMA node is not meant to contain 
you. A container is, and that is why it is called a container.

NUMA just means what is the *best* node to put my memory.
Now, if you actually say, through you syscalls "this is the node it 
should live in", then you have a constraint, that to the best of my 
knowledge is respected.

Now isolation here, is done in the container boundary. (cgroups, to be 
generic).
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