Re: [PATCH v3] mm: add thp_utilization metrics to /proc/thp_utilization

[Yang Shi]

On Fri, Aug 5, 2022 at 12:52 PM Alex Zhu (Kernel) <alexlzhu@xxxxxx> wrote:
>
>
> >
> > Ah!  So when that exists, this interface tells us "how well" we're doing.
> >
>
> Yes, exactly.
> >
> > Yeah, debugfs seems like a better place.  And I'd love to see the shrinker
> > code.  Before you mentioned that I was having all kinds of peculiar
> > feelings about this code.  For example, suppose you have incredibly hot
> > 256kB of data, but the other 1792kB of data are never touched ... that
> > could cause us to do entirely the wrong thing and break up this THP.
> > Having it as a shrinker makes sense because the hot 256kB will keep the
> > THP from reaching the end of the list and being reclaimed.
>
> Sounds good, I’ll move this to debugfs then. Will follow up with the shrinker code
> in another patch. The shrinker relies on this scanning thread to figure out which
> THPs to reclaim.

I'm wondering whether you could reuse the THP deferred split shrinker
or not. It is already memcg aware.

>
> What are your thoughts regarding integrating this with DAMON?