Re: [PATCH v2 2/3] mm: Force update of mem cgroup soft limit tree on usage excess

[Michal Hocko]

On Fri 26-02-21 16:56:28, Tim Chen wrote:
> 
> 
> On 2/26/21 12:52 AM, Michal Hocko wrote:
> 
> >>
> >> Michal,
> >>
> >> Let's take an extreme case where memcg 1 always generate the
> >> first event and memcg 2 generates the rest of 128*8-1 events
> >> and the pattern repeat.
> > 
> > I do not follow. Events are per-memcg, aren't they?
> > 	__this_cpu_read(memcg->vmstats_percpu->targets[target]);
> > 	[...]
> > 	__this_cpu_write(memcg->vmstats_percpu->targets[target], next);
> > 
> 
> You are right. My previous reasoning is incorrect as the sampling is done per memcg.
> I'll do some additional debugging on why memcg is not on the tree.

OK, thanks for the confirmation. I think we want to do 2 things. Remove
the soft limit specific threshold and stay with a single one and
recognize THPs.
-- 
Michal Hocko
SUSE Labs