Re: [PATCH v3] mm, sysctl: make NUMA stats configurable

[Andrew Morton]

On Tue, 10 Oct 2017 19:51:43 +0200 Michal Hocko <mhocko@xxxxxxxxxx> wrote:

> On Tue 10-10-17 08:39:47, Dave Hansen wrote:
> > On 10/10/2017 07:57 AM, Michal Hocko wrote:
> > >> But, let's be honest, this leaves us with an option that nobody is ever
> > >> going to turn on.  IOW, nobody except a very small portion of our users
> > >> will ever see any benefit from this.
> > > But aren't those small groups who would like to squeeze every single
> > > cycle out from the page allocator path the targeted audience?
> > 
> > They're the reason we started looking at this.  They also care the most.
> > 
> > But, the cost of these stats, especially we get more and more cores in a
> > NUMA node is really making them show up in profiles.  It would be nice
> > to get rid of them there, too.
> 
> I am not opposing to the auto mode. I am just not sure it is a safe
> default and I also think that we should add this on top if it is really
> needed.

Yup.  Let's keep things simple unless a real need is demonstrated, please.