Message-ID: <507CD2FA.8000009@jp.fujitsu.com>
Date: Tue, 16 Oct 2012 12:22:34 +0900
From: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
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To: Glauber Costa <glommer@parallels.com>
CC: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        Andrew Morton <akpm@linux-foundation.org>,
        Mel Gorman <mgorman@suse.de>, Suleiman Souhlal <suleiman@google.com>,
        Tejun Heo <tj@kernel.org>, cgroups@vger.kernel.org,
        Michal Hocko <mhocko@suse.cz>, Johannes Weiner <hannes@cmpxchg.org>,
        Greg Thelen <gthelen@google.com>, devel@openvz.org,
        Frederic Weisbecker <fweisbec@gmail.com>
Subject: Re: [PATCH v4 02/14] memcg: Reclaim when more than one page needed.
References: <1349690780-15988-1-git-send-email-glommer@parallels.com> <1349690780-15988-3-git-send-email-glommer@parallels.com>
In-Reply-To: <1349690780-15988-3-git-send-email-glommer@parallels.com>
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(2012/10/08 19:06), Glauber Costa wrote:
> From: Suleiman Souhlal <ssouhlal@FreeBSD.org>
> 
> mem_cgroup_do_charge() was written before kmem accounting, and expects
> three cases: being called for 1 page, being called for a stock of 32
> pages, or being called for a hugepage.  If we call for 2 or 3 pages (and
> both the stack and several slabs used in process creation are such, at
> least with the debug options I had), it assumed it's being called for
> stock and just retried without reclaiming.
> 
> Fix that by passing down a minsize argument in addition to the csize.
> 
> And what to do about that (csize == PAGE_SIZE && ret) retry?  If it's
> needed at all (and presumably is since it's there, perhaps to handle
> races), then it should be extended to more than PAGE_SIZE, yet how far?
> And should there be a retry count limit, of what?  For now retry up to
> COSTLY_ORDER (as page_alloc.c does) and make sure not to do it if
> __GFP_NORETRY.
> 
> [v4: fixed nr pages calculation pointed out by Christoph Lameter ]
> 
> Signed-off-by: Suleiman Souhlal <suleiman@google.com>
> Signed-off-by: Glauber Costa <glommer@parallels.com>
> Reviewed-by: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> Acked-by: Michal Hocko <mhocko@suse.cz>
> Acked-by: Johannes Weiner <hannes@cmpxchg.org>

Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>


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