Re: [PATCH 4/4] mm/memcg: refine mem_cgroup_threshold_ary->current_threshold calculation

[Roman Gushchin]

On Tue, Jan 11, 2022 at 01:03:02AM +0000, Wei Yang wrote:
> mem_cgroup_threshold_ary->current_threshold points to the last entry
> who's threshold is less or equal to usage.
> 
> Instead of iterating entries to get the correct index, we can leverage
> primary->current_threshold to get it. If the threshold added is less or
> equal to usage, current_threshold should increase by one. Otherwise, it
> doesn't change.

How big is usually an array of thresholds? If it's not huge, likely
any savings won't be really noticeable (it's not a hot path and there
is an rc_synchronize() below).

So I agree with Michal that a better justification is really needed.

Thanks!