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

[Pekka Enberg]

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