Re: [PATCH 3/3] mm: adjust vm_committed_as_batch according to vm overcommit policy

[Feng Tang]

On Fri, May 15, 2020 at 03:44:43PM +0800, Michal Hocko wrote:
> On Fri 08-05-20 15:25:17, Feng Tang wrote:
> > When checking a performance change for will-it-scale scalability
> > mmap test [1], we found very high lock contention for spinlock of
> > percpu counter 'vm_committed_as':
> 
> Btw. you are focusing on a microbenchmark here but I believe that there
> are non-synthetic worklaods which would benefit from a larger batch.
> E.g. large in memory databases which do large mmaps during startups
> from multiple threads.

I imagined cases like this too :) but was not sure there are such cases.
So I only put down the the benchmark I've worked with in 0day.

Thanks,
Feng

> -- 
> Michal Hocko
> SUSE Labs