Re: [PATCH 08/11] memcg: disable kmem code when not in use.

From: Kamezawa Hiroyuki
Date: Tue Jun 26 2012 - 01:53:33 EST


(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@xxxxxxxxxxxxx>
> CC: Christoph Lameter <cl@xxxxxxxxx>
> CC: Pekka Enberg <penberg@xxxxxxxxxxxxxx>
> CC: Michal Hocko <mhocko@xxxxxxx>
> CC: Kamezawa Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
> CC: Johannes Weiner <hannes@xxxxxxxxxxx>
> CC: Suleiman Souhlal <suleiman@xxxxxxxxxx>

Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>

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