Re: [PATCH 6.6.y] mm/damon/core: don't skip damos_adjust_quota() while esz is not zero

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
- [Medium] mm: commit message references nonexistent damos_quota_is_set()
- [Low] mm: outdated comment for damos_set_effective_quota()
--

commit bdd4b48218af232c248d2db96f0af460e859f59e
Author: SJ Park <sj@kernel.org>

mm/damon/core: don't skip damos_adjust_quota() while esz is not zero

DAMOS could unexpectedly stop working when a user disables quota using the
online parameters commit feature. Fix it by correcting a wrong quota
unset check in damos_adjust_quota().

Link: https://lore.kernel.org/20260916135020.86483-1-sj@kernel.org

> Other logic for catching that uses damos_quota_is_set(), which understands
> the fact and therefore checks the effective size quota in addition to the
> user setup.  Fix the issue by using damos_quota_is_set() in
> damos_adjust_quota() to determine if its works should be skipped.

[Severity: Medium]
The commit message states the fix uses damos_quota_is_set(). However, the
code below checks the fields directly inline. Should the commit message
be updated to reflect the inline check?

> diff --git a/mm/damon/core.c b/mm/damon/core.c
> index fe91b296f4c66..bd46a63b611cf 100644
> --- a/mm/damon/core.c
> +++ b/mm/damon/core.c
> @@ -1087,7 +1087,7 @@ static void damos_adjust_quota(struct damon_ctx *c, struct damos *s)
>  	unsigned long cumulated_sz;
>  	unsigned int score, max_score = 0;
>  
> -	if (!quota->ms && !quota->sz)
> +	if (!quota->esz && !quota->ms && !quota->sz)
>  		return;

[Severity: Low]
With this change, damos_adjust_quota() can proceed even when quota->ms and
quota->sz are zero. This allows damos_set_effective_quota() to be called
later in the function during a new charge window:

	if (!time_in_range_open(...)) {
		...
		damos_set_effective_quota(quota);
	}

Does this make the comment above damos_set_effective_quota() outdated? It
currently states:

/* Shouldn't be called if quota->ms and quota->sz are zero */
static void damos_set_effective_quota(struct damos_quota *quota)

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261003154818.24786-1-sj@kernel.org?part=1