Hello,

On Fri, Sep 21, 2012 at 12:41:52PM +0300, Pekka Enberg wrote:

quoted

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.

Not necessarily disagreeing, but I don't think it's helpful to set the
bar impossibly high.  Even static_key doesn't have "exactly *zero*"
impact.  Let's stick to as minimal as possible when not in use and
reasonable in use.

And, yeah, this one can be easily solved by using static_key.

Thanks.

-- 
tejun