Message-ID: <4FE94DD3.5060404@jp.fujitsu.com>
Date: Tue, 26 Jun 2012 14:51:15 +0900
From: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
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To: Glauber Costa <glommer@parallels.com>
CC: cgroups@vger.kernel.org, linux-mm@kvack.org,
        Andrew Morton <akpm@linux-foundation.org>,
        linux-kernel@vger.kernel.org, Frederic Weisbecker <fweisbec@gmail.com>,
        David Rientjes <rientjes@google.com>,
        Pekka Enberg <penberg@kernel.org>, Michal Hocko <mhocko@suse.cz>,
        Johannes Weiner <hannes@cmpxchg.org>, Christoph Lameter <cl@linux.com>,
        devel@openvz.org, Tejun Heo <tj@kernel.org>,
        Pekka Enberg <penberg@cs.helsinki.fi>,
        Suleiman Souhlal <suleiman@google.com>
Subject: Re: [PATCH 08/11] memcg: disable kmem code when not in use.
References: <1340633728-12785-1-git-send-email-glommer@parallels.com> <1340633728-12785-9-git-send-email-glommer@parallels.com>
In-Reply-To: <1340633728-12785-9-git-send-email-glommer@parallels.com>
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(2012/06/25 23:15), Glauber Costa wrote:
> We can use jump labels to patch the code in or out
> when not used.
> 
> Because the assignment: memcg->kmem_accounted = true
> is done after the jump labels increment, we guarantee
> that the root memcg will always be selected until
> all call sites are patched (see mem_cgroup_kmem_enabled).
> This guarantees that no mischarges are applied.
> 
> Jump label decrement happens when the last reference
> count from the memcg dies. This will only happen when
> the caches are all dead.
> 
> Signed-off-by: Glauber Costa <glommer@parallels.com>
> CC: Christoph Lameter <cl@linux.com>
> CC: Pekka Enberg <penberg@cs.helsinki.fi>
> CC: Michal Hocko <mhocko@suse.cz>
> CC: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> CC: Johannes Weiner <hannes@cmpxchg.org>
> CC: Suleiman Souhlal <suleiman@google.com>

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

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