Re: [RFC-PATCH 1/2] mm: Add __GFP_NO_LOCKS flag

[Thomas Gleixner]

On Tue, Aug 18 2020 at 06:53, Paul E. McKenney wrote:
> On Tue, Aug 18, 2020 at 09:43:44AM +0200, Michal Hocko wrote:
>> Thomas had a good point that it doesn't really make much sense to
>> optimize for flooders because that just makes them more effective.
>
> The point is not to make the flooders go faster, but rather for the
> system to be robust in the face of flooders.  Robust as in harder for
> a flooder to OOM the system.
>
> And reducing the number of post-grace-period cache misses makes it
> easier for the callback-invocation-time memory freeing to keep up with
> the flooder, thus avoiding (or at least delaying) the OOM.

Throttling the flooder is incresing robustness far more than reducing
cache misses.

Thanks,

        tglx