Re: [PATCH] mm/damon/tests/core-kunit: add test for unconditionally skipping the last region

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] The patch introduces a KUnit test for a bug in `damos_skip_charged_region()` but completely omits the code fix, causing the test to fail unconditionally and break CI.
--

commit 7f67629ee782b9649498afa3088f50459bfb8f3b
Author: Liew Rui Yan <aethernet65535@gmail.com>

mm/damon/tests/core-kunit: add test for unconditionally skipping the last region

This commit introduces a KUnit test to verify that the last region is not
skipped before being processed.

> diff --git a/mm/damon/tests/core-kunit.h b/mm/damon/tests/core-kunit.h
> index 4a536d41cdb2d..90b0fda34fba2 100644
> --- a/mm/damon/tests/core-kunit.h
> +++ b/mm/damon/tests/core-kunit.h
[ ... ]
> @@ -1632,6 +1632,48 @@ static void damon_test_rand(struct kunit *test)
>  	}
>  }
>  
> +static void damon_test_last_region_quota_reset(struct kunit *test)
> +{
> +	struct damos s = {0};
> +	struct damon_target *t;
> +	struct damon_region *r1, *r2;
> +	unsigned long min_region_sz = 10;
> +	bool skipped;
[ ... ]
> +	s.quota.charge_target_from = t;
> +	s.quota.charge_addr_from = r1->ar.end;
> +
> +	skipped = damos_skip_charged_region(t, r2, &s, min_region_sz);
> +
> +	/* 'r2' is not processed, it should not skip */
> +	KUNIT_EXPECT_EQ(test, skipped, false);

[Severity: Medium]
Does this patch omit the fix for the core logic?

Without an accompanying fix for damos_skip_charged_region() in
mm/damon/core.c, won't this new test unconditionally fail and break CI?

Because the underlying bug is not fixed in this patch, the old logic still
triggers and returns true when it processes the last region:

mm/damon/core.c:damos_skip_charged_region() {
	...
	if (quota->charge_target_from) {
		if (t != quota->charge_target_from)
			return true;
		if (r == damon_last_region(t)) {
			quota->charge_target_from = NULL;
			quota->charge_addr_from = 0;
			return true;
		}
	...
}

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260831113735.3349-1-aethernet65535@gmail.com?part=1