Re: [PATCH v3 09/16] sl[au]b: always get the cache from its page inkfree

From: Pekka Enberg
Date: Fri Sep 21 2012 - 05:41:47 EST


On Fri, 21 Sep 2012, Glauber Costa wrote:
> > We should assume that most distributions enable CONFIG_MEMCG_KMEM,
> > right? Therfore, any performance impact should be dependent on whether
> > or not kmem memcg is *enabled* at runtime or not.
> >
> > Can we use the "static key" thingy introduced by tracing folks for this?
>
> Yes.
>
> I am already using static keys extensively in this patchset, and that is
> how I intend to handle this particular case.

Cool.

The key point here is that !CONFIG_MEMCG_KMEM should have exactly *zero*
performance impact and CONFIG_MEMCG_KMEM disabled at runtime should have
absolute minimal impact.

Pekka
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