From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx202.postini.com [74.125.245.202]) by kanga.kvack.org (Postfix) with SMTP id 057206B0044 for ; Tue, 24 Apr 2012 17:38:25 -0400 (EDT) Message-ID: <4F971CC2.3090109@parallels.com> Date: Tue, 24 Apr 2012 18:36:02 -0300 From: Glauber Costa MIME-Version: 1.0 Subject: Re: [PATCH 17/23] kmem controller charge/uncharge infrastructure References: <1334959051-18203-1-git-send-email-glommer@parallels.com> <1335138820-26590-6-git-send-email-glommer@parallels.com> <20120424142232.GC8626@somewhere> <4F96BB62.1030900@parallels.com> In-Reply-To: Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: David Rientjes Cc: Frederic Weisbecker , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, devel@openvz.org, KAMEZAWA Hiroyuki , Michal Hocko , Johannes Weiner , Greg Thelen , Suleiman Souhlal , Christoph Lameter , Pekka Enberg On 04/24/2012 05:25 PM, David Rientjes wrote: > On Tue, 24 Apr 2012, Glauber Costa wrote: > >> I think memcg is not necessarily wrong. That is because threads in a process >> share an address space, and you will eventually need to map a page to deliver >> it to userspace. The mm struct points you to the owner of that. >> >> But that is not necessarily true for things that live in the kernel address >> space. >> >> Do you view this differently ? >> > > Yes, for user memory, I see charging to p->mm->owner as allowing that > process to eventually move and be charged to a different memcg and there's > no way to do proper accounting if the charge is split amongst different > memcgs because of thread membership to a set of memcgs. This is > consistent with charges for shared memory being moved when a thread > mapping it moves to a new memcg, as well. But that's the problem. When we are dealing with kernel memory, we are allocating a whole slab page. It is essentially impossible to track, given a page, which task allocated which object. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org