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

[Kamezawa Hiroyuki]

(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 at parallels.com>
> CC: Christoph Lameter <cl at linux.com>
> CC: Pekka Enberg <penberg at cs.helsinki.fi>
> CC: Michal Hocko <mhocko at suse.cz>
> CC: Kamezawa Hiroyuki <kamezawa.hiroyu at jp.fujitsu.com>
> CC: Johannes Weiner <hannes at cmpxchg.org>
> CC: Suleiman Souhlal <suleiman at google.com>

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