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

From: Michal Hocko
Date: Tue Oct 10 2017 - 13:51:51 EST


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.
--
Michal Hocko
SUSE Labs