Re: [PATCH] mm/damon/core: add short circuit for esz<min_region_sz in damos_adjust_quota()

From: Liew Rui Yan

Date: Mon Sep 14 2026 - 10:44:05 EST


On Sun, 13 Sep 2026 09:20:45 -0700 SJ Park <sj@xxxxxxxxxx> wrote:

> Hi Liew,
>
>
> From the next time, please complete discussions on the previous version before
> posting a new version. For example, in this case, you could replied to my last
> reply to the previous version of this patch saying you will accept my suggested
> changes and wait a reasonable time to decide there is no other opinions.

Thank you for your guidance. From the next time, I will reply and say
if I will accept your suggestions.

>
> I think the subject is not very clear. How about something like, "skip quota
> score setup when quota is full"?

Sure, it is shorter and more understandable.

>
> On Sun, 13 Sep 2026 19:01:38 +0800 Liew Rui Yan <aethernet65535@xxxxxxxxx> wrote:
>
> > After damos_set_effective_quota(), the effective size quota may be lower
> > than min_region_sz (e.g., when the temporal quota goal is [over-]achieved).
>
> This sounds unnecessarily specific and doesn't cover all the case. What about
>
> "In damos_adjust_quota(), the quota could already be full."

Agree, that makes sense. Since users who is using temporal quota
auto-tuning should know what happens when goal is achieved.

>
> >
> > In this situation, damos_adjust_quota() will still calculates
> > quota->min_score. However, this min_score will not be used in this
> > window, because in damon_do_apply_schemes(), damos_quota_is_full() will
> > always returns true, preventing the scheme from being applied to any
> > region.
> >
> > Therefore, add a short circuit for 'esz < min_region_sz' schemes to
> > early return from damos_adjust_quota() before calculating min_score.
> >
> > Signed-off-by: Liew Rui Yan <aethernet65535@xxxxxxxxx>
>
> Assuming you agree to above suggestions,

Yes, I agree those all suggestions.

>
> Reviewed-by: SJ Park <sj@xxxxxxxxxx>
>
> With the above assumption, I modified this patch with the suggestions and
> applied to damon/next [1] tree. I will repost it for mm.git merge after a
> week. So, if you are ok with the plan, no action from your side is needed.
>
> Please let me know if you have different opinions.
>
> [1] https://origin.kernel.org/doc/html/latest/mm/damon/maintainer-profile.html#scm-trees

Best regards,
Rui Yan