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

[Tim Chen]

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.

Tim