[PATCH v2 0/5] mm/damon/tests/core-kunit: extend existing test scenarios

[PATCH v2 0/5] mm/damon/tests/core-kunit: extend existing test scenarios

[Shu Anzai]

Improve the KUnit test coverage for DAMON. 

The five patches in this series respectively extend damon_test_split_at(), 
damon_test_merge_two(), damon_test_merge_regions_of(), 
damon_test_split_regions_of(), and damos_test_commit_quota_goal().

Changes from v1:
- Split the original patch into five smaller patches.
- Remove a newly added region from damon_test_merge_regions_of() 
  to avoid an obvious test case.
- Restore the test case in damon_test_split_regions_of() 
  that was previously removed.

Shu Anzai (5):
  mm/damon/tests/core-kunit: verify the 'age' field in
    damon_test_split_at()
  mm/damon/tests/core-kunit: verify the 'age' and 'nr_accesses_bp'
    fields in damon_test_merge_two()
  mm/damon/tests/core-kunit: add a test case for region merge size limit
    in damon_test_merge_regions_of()
  mm/damon/tests/core-kunit: add test cases for multiple regions in
    damon_test_split_regions_of()
  mm/damon/tests/core-kunit: remove a redundant test case and add a new
    test case in damos_test_commit_quota_goal()

 mm/damon/tests/core-kunit.h | 50 +++++++++++++++++++++++++++++--------
 1 file changed, 39 insertions(+), 11 deletions(-)

-- 
2.43.0

[PATCH v2 1/5] mm/damon/tests/core-kunit: verify the 'age' field in damon_test_split_at()

[Shu Anzai]

Extend damon_test_split_at() to verify the 'age' field.

Signed-off-by: Shu Anzai <shu17az@gmail.com>
---
 mm/damon/tests/core-kunit.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/mm/damon/tests/core-kunit.h b/mm/damon/tests/core-kunit.h
index f59ae7ee19a0..88ec046f4942 100644
--- a/mm/damon/tests/core-kunit.h
+++ b/mm/damon/tests/core-kunit.h
@@ -158,6 +158,7 @@ static void damon_test_split_at(struct kunit *test)
 	r->nr_accesses_bp = 420000;
 	r->nr_accesses = 42;
 	r->last_nr_accesses = 15;
+	r->age = 10;
 	damon_add_region(r, t);
 	damon_split_region_at(t, r, 25);
 	KUNIT_EXPECT_EQ(test, r->ar.start, 0ul);
@@ -170,6 +171,7 @@ static void damon_test_split_at(struct kunit *test)
 	KUNIT_EXPECT_EQ(test, r->nr_accesses_bp, r_new->nr_accesses_bp);
 	KUNIT_EXPECT_EQ(test, r->nr_accesses, r_new->nr_accesses);
 	KUNIT_EXPECT_EQ(test, r->last_nr_accesses, r_new->last_nr_accesses);
+	KUNIT_EXPECT_EQ(test, r->age, r_new->age);
 
 	damon_free_target(t);
 }
-- 
2.43.0

Re: [PATCH v2 1/5] mm/damon/tests/core-kunit: verify the 'age' field in damon_test_split_at()

[SeongJae Park]

On Wed, 24 Dec 2025 04:21:56 +0000 Shu Anzai <shu17az@gmail.com> wrote:

> Extend damon_test_split_at() to verify the 'age' field.
> 
> Signed-off-by: Shu Anzai <shu17az@gmail.com>

Reviewed-by: SeongJae Park <sj@kernel.org>

> ---
>  mm/damon/tests/core-kunit.h | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/mm/damon/tests/core-kunit.h b/mm/damon/tests/core-kunit.h
> index f59ae7ee19a0..88ec046f4942 100644
> --- a/mm/damon/tests/core-kunit.h
> +++ b/mm/damon/tests/core-kunit.h
> @@ -158,6 +158,7 @@ static void damon_test_split_at(struct kunit *test)
>  	r->nr_accesses_bp = 420000;
>  	r->nr_accesses = 42;
>  	r->last_nr_accesses = 15;
> +	r->age = 10;
>  	damon_add_region(r, t);
>  	damon_split_region_at(t, r, 25);
>  	KUNIT_EXPECT_EQ(test, r->ar.start, 0ul);
> @@ -170,6 +171,7 @@ static void damon_test_split_at(struct kunit *test)
>  	KUNIT_EXPECT_EQ(test, r->nr_accesses_bp, r_new->nr_accesses_bp);
>  	KUNIT_EXPECT_EQ(test, r->nr_accesses, r_new->nr_accesses);
>  	KUNIT_EXPECT_EQ(test, r->last_nr_accesses, r_new->last_nr_accesses);
> +	KUNIT_EXPECT_EQ(test, r->age, r_new->age);
>  
>  	damon_free_target(t);
>  }
> -- 
> 2.43.0


Thanks,
SJ

[PATCH v2 2/5] mm/damon/tests/core-kunit: verify the 'age' and 'nr_accesses_bp' fields in damon_test_merge_two()

[Shu Anzai]

Extend damon_test_merge_two() to verify the 'age' and 
'nr_accesses_bp' fields.

Signed-off-by: Shu Anzai <shu17az@gmail.com>
---
 mm/damon/tests/core-kunit.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/mm/damon/tests/core-kunit.h b/mm/damon/tests/core-kunit.h
index 88ec046f4942..6e301113e103 100644
--- a/mm/damon/tests/core-kunit.h
+++ b/mm/damon/tests/core-kunit.h
@@ -192,6 +192,7 @@ static void damon_test_merge_two(struct kunit *test)
 	}
 	r->nr_accesses = 10;
 	r->nr_accesses_bp = 100000;
+	r->age = 9;
 	damon_add_region(r, t);
 	r2 = damon_new_region(100, 300);
 	if (!r2) {
@@ -200,12 +201,15 @@ static void damon_test_merge_two(struct kunit *test)
 	}
 	r2->nr_accesses = 20;
 	r2->nr_accesses_bp = 200000;
+	r2->age = 21;
 	damon_add_region(r2, t);
 
 	damon_merge_two_regions(t, r, r2);
 	KUNIT_EXPECT_EQ(test, r->ar.start, 0ul);
 	KUNIT_EXPECT_EQ(test, r->ar.end, 300ul);
 	KUNIT_EXPECT_EQ(test, r->nr_accesses, 16u);
+	KUNIT_EXPECT_EQ(test, r->nr_accesses_bp, 160000u);
+	KUNIT_EXPECT_EQ(test, r->age, 17u);
 
 	i = 0;
 	damon_for_each_region(r3, t) {
-- 
2.43.0

Re: [PATCH v2 2/5] mm/damon/tests/core-kunit: verify the 'age' and 'nr_accesses_bp' fields in damon_test_merge_two()

[SeongJae Park]

On Wed, 24 Dec 2025 04:21:57 +0000 Shu Anzai <shu17az@gmail.com> wrote:

> Extend damon_test_merge_two() to verify the 'age' and 
> 'nr_accesses_bp' fields.
> 
> Signed-off-by: Shu Anzai <shu17az@gmail.com>

Reviewed-by: SeongJae Park <sj@kernel.org>


Thanks,
SJ

[...]

[PATCH v2 3/5] mm/damon/tests/core-kunit: add a test case for region merge size limit in damon_test_merge_regions_of()

[Shu Anzai]

Add a test case in damon_test_merge_regions_of() to verify that 
two adjacent regions are not merged if the resulting region would 
exceed the specified size limit.

Signed-off-by: Shu Anzai <shu17az@gmail.com>
---
 mm/damon/tests/core-kunit.h | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/mm/damon/tests/core-kunit.h b/mm/damon/tests/core-kunit.h
index 6e301113e103..2eb6f41635a8 100644
--- a/mm/damon/tests/core-kunit.h
+++ b/mm/damon/tests/core-kunit.h
@@ -238,12 +238,12 @@ static void damon_test_merge_regions_of(struct kunit *test)
 {
 	struct damon_target *t;
 	struct damon_region *r;
-	unsigned long sa[] = {0, 100, 114, 122, 130, 156, 170, 184};
-	unsigned long ea[] = {100, 112, 122, 130, 156, 170, 184, 230};
-	unsigned int nrs[] = {0, 0, 10, 10, 20, 30, 1, 2};
+	unsigned long sa[] = {0, 100, 114, 122, 130, 156, 170, 184, 230};
+	unsigned long ea[] = {100, 112, 122, 130, 156, 170, 184, 230, 10170};
+	unsigned int nrs[] = {0, 0, 10, 10, 20, 30, 1, 2, 5};
 
-	unsigned long saddrs[] = {0, 114, 130, 156, 170};
-	unsigned long eaddrs[] = {112, 130, 156, 170, 230};
+	unsigned long saddrs[] = {0, 114, 130, 156, 170, 230};
+	unsigned long eaddrs[] = {112, 130, 156, 170, 230, 10170};
 	int i;
 
 	t = damon_new_target();
@@ -261,9 +261,9 @@ static void damon_test_merge_regions_of(struct kunit *test)
 	}
 
 	damon_merge_regions_of(t, 9, 9999);
-	/* 0-112, 114-130, 130-156, 156-170 */
-	KUNIT_EXPECT_EQ(test, damon_nr_regions(t), 5u);
-	for (i = 0; i < 5; i++) {
+	/* 0-112, 114-130, 130-156, 156-170, 170-230, 230-10170 */
+	KUNIT_EXPECT_EQ(test, damon_nr_regions(t), 6u);
+	for (i = 0; i < 6; i++) {
 		r = __nth_region_of(t, i);
 		KUNIT_EXPECT_EQ(test, r->ar.start, saddrs[i]);
 		KUNIT_EXPECT_EQ(test, r->ar.end, eaddrs[i]);
-- 
2.43.0

Re: [PATCH v2 3/5] mm/damon/tests/core-kunit: add a test case for region merge size limit in damon_test_merge_regions_of()

[SeongJae Park]

On Wed, 24 Dec 2025 04:21:58 +0000 Shu Anzai <shu17az@gmail.com> wrote:

> Add a test case in damon_test_merge_regions_of() to verify that 
> two adjacent regions are not merged if the resulting region would 
> exceed the specified size limit.
> 
> Signed-off-by: Shu Anzai <shu17az@gmail.com>

Reviewed-by: SeongJae Park <sj@kernel.org>


Thanks,
SJ

[...]

[PATCH v2 4/5] mm/damon/tests/core-kunit: add test cases for multiple regions in damon_test_split_regions_of()

[Shu Anzai]

Extend damon_test_split_regions_of() to verify that it correctly handles 
multiple regions with various 'min_sz_region'.

Signed-off-by: Shu Anzai <shu17az@gmail.com>
---
 mm/damon/tests/core-kunit.h | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/mm/damon/tests/core-kunit.h b/mm/damon/tests/core-kunit.h
index 2eb6f41635a8..36622a2c11f1 100644
--- a/mm/damon/tests/core-kunit.h
+++ b/mm/damon/tests/core-kunit.h
@@ -275,6 +275,9 @@ static void damon_test_split_regions_of(struct kunit *test)
 {
 	struct damon_target *t;
 	struct damon_region *r;
+	unsigned long sa[] = {0, 300, 500};
+	unsigned long ea[] = {220, 400, 700};
+	int i;
 
 	t = damon_new_target();
 	if (!t)
@@ -301,6 +304,24 @@ static void damon_test_split_regions_of(struct kunit *test)
 	damon_split_regions_of(t, 4, 1);
 	KUNIT_EXPECT_LE(test, damon_nr_regions(t), 4u);
 	damon_free_target(t);
+
+	t = damon_new_target();
+	if (!t)
+		kunit_skip(test, "third target alloc fail");
+	for (i = 0; i < ARRAY_SIZE(sa); i++) {
+		r = damon_new_region(sa[i], ea[i]);
+		if (!r) {
+			damon_free_target(t);
+			kunit_skip(test, "region alloc fail");
+		}
+		damon_add_region(r, t);
+	}
+	damon_split_regions_of(t, 4, 5);
+	KUNIT_EXPECT_LE(test, damon_nr_regions(t), 12u);
+	damon_for_each_region(r, t) {
+		KUNIT_EXPECT_GE(test, damon_sz_region(r) % 5ul, 0ul);
+	}
+	damon_free_target(t);
 }
 
 static void damon_test_ops_registration(struct kunit *test)
-- 
2.43.0

Re: [PATCH v2 4/5] mm/damon/tests/core-kunit: add test cases for multiple regions in damon_test_split_regions_of()

[SeongJae Park]

On Wed, 24 Dec 2025 04:21:59 +0000 Shu Anzai <shu17az@gmail.com> wrote:

> Extend damon_test_split_regions_of() to verify that it correctly handles 
> multiple regions with various 'min_sz_region'.
> 
> Signed-off-by: Shu Anzai <shu17az@gmail.com>
> ---
>  mm/damon/tests/core-kunit.h | 21 +++++++++++++++++++++
>  1 file changed, 21 insertions(+)
> 
> diff --git a/mm/damon/tests/core-kunit.h b/mm/damon/tests/core-kunit.h
> index 2eb6f41635a8..36622a2c11f1 100644
> --- a/mm/damon/tests/core-kunit.h
> +++ b/mm/damon/tests/core-kunit.h
> @@ -275,6 +275,9 @@ static void damon_test_split_regions_of(struct kunit *test)
>  {
>  	struct damon_target *t;
>  	struct damon_region *r;
> +	unsigned long sa[] = {0, 300, 500};
> +	unsigned long ea[] = {220, 400, 700};
> +	int i;
>  
>  	t = damon_new_target();
>  	if (!t)
> @@ -301,6 +304,24 @@ static void damon_test_split_regions_of(struct kunit *test)
>  	damon_split_regions_of(t, 4, 1);
>  	KUNIT_EXPECT_LE(test, damon_nr_regions(t), 4u);
>  	damon_free_target(t);
> +
> +	t = damon_new_target();
> +	if (!t)
> +		kunit_skip(test, "third target alloc fail");
> +	for (i = 0; i < ARRAY_SIZE(sa); i++) {
> +		r = damon_new_region(sa[i], ea[i]);
> +		if (!r) {
> +			damon_free_target(t);
> +			kunit_skip(test, "region alloc fail");
> +		}
> +		damon_add_region(r, t);
> +	}
> +	damon_split_regions_of(t, 4, 5);
> +	KUNIT_EXPECT_LE(test, damon_nr_regions(t), 12u);
> +	damon_for_each_region(r, t) {
> +		KUNIT_EXPECT_GE(test, damon_sz_region(r) % 5ul, 0ul);
> +	}

Nit.  The above braces for single statement is unnecessary.

> +	damon_free_target(t);
>  }
>  
>  static void damon_test_ops_registration(struct kunit *test)
> -- 
> 2.43.0

Other than the above trivial nit for the unnecessary braces,

Reviewed-by: SeongJae Park <sj@kernel.org>


Thanks,
SJ

Re: [PATCH v2 4/5] mm/damon/tests/core-kunit: add test cases for multiple regions in damon_test_split_regions_of()

[SeongJae Park]

On Tue, 23 Dec 2025 21:34:06 -0800 SeongJae Park <sj@kernel.org> wrote:

> On Wed, 24 Dec 2025 04:21:59 +0000 Shu Anzai <shu17az@gmail.com> wrote:
> 
> > Extend damon_test_split_regions_of() to verify that it correctly handles 
> > multiple regions with various 'min_sz_region'.
> > 
> > Signed-off-by: Shu Anzai <shu17az@gmail.com>
> > ---
> >  mm/damon/tests/core-kunit.h | 21 +++++++++++++++++++++
> >  1 file changed, 21 insertions(+)
> > 
> > diff --git a/mm/damon/tests/core-kunit.h b/mm/damon/tests/core-kunit.h
> > index 2eb6f41635a8..36622a2c11f1 100644
> > --- a/mm/damon/tests/core-kunit.h
> > +++ b/mm/damon/tests/core-kunit.h
> > @@ -275,6 +275,9 @@ static void damon_test_split_regions_of(struct kunit *test)
> >  {
> >  	struct damon_target *t;
> >  	struct damon_region *r;
> > +	unsigned long sa[] = {0, 300, 500};
> > +	unsigned long ea[] = {220, 400, 700};
> > +	int i;
> >  
> >  	t = damon_new_target();
> >  	if (!t)
> > @@ -301,6 +304,24 @@ static void damon_test_split_regions_of(struct kunit *test)
> >  	damon_split_regions_of(t, 4, 1);
> >  	KUNIT_EXPECT_LE(test, damon_nr_regions(t), 4u);
> >  	damon_free_target(t);
> > +
> > +	t = damon_new_target();
> > +	if (!t)
> > +		kunit_skip(test, "third target alloc fail");
> > +	for (i = 0; i < ARRAY_SIZE(sa); i++) {
> > +		r = damon_new_region(sa[i], ea[i]);
> > +		if (!r) {
> > +			damon_free_target(t);
> > +			kunit_skip(test, "region alloc fail");
> > +		}
> > +		damon_add_region(r, t);
> > +	}
> > +	damon_split_regions_of(t, 4, 5);
> > +	KUNIT_EXPECT_LE(test, damon_nr_regions(t), 12u);
> > +	damon_for_each_region(r, t) {
> > +		KUNIT_EXPECT_GE(test, damon_sz_region(r) % 5ul, 0ul);
> > +	}
> 
> Nit.  The above braces for single statement is unnecessary.

Andrew, could you please pick this series with below attaching fixup for this
one?

> 
> > +	damon_free_target(t);
> >  }
> >  
> >  static void damon_test_ops_registration(struct kunit *test)
> > -- 
> > 2.43.0
> 
> Other than the above trivial nit for the unnecessary braces,
> 
> Reviewed-by: SeongJae Park <sj@kernel.org>
> 
> 
> Thanks,
> SJ


Thanks,
SJ

==== >8 ====
From dde3e0e84056f85cd5cbface38c1f617bfbd0bd4 Mon Sep 17 00:00:00 2001
From: SeongJae Park <sj@kernel.org>
Date: Wed, 24 Dec 2025 07:27:04 -0800
Subject: [PATCH] mm/damon/tests/core-kunit: remove braces for a single
 statement

damon_test_split_regions_of() has braces for a single statement, which
is unnecessary.  Remove it.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/tests/core-kunit.h | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/mm/damon/tests/core-kunit.h b/mm/damon/tests/core-kunit.h
index 36622a2c11f1..252ce3e001c8 100644
--- a/mm/damon/tests/core-kunit.h
+++ b/mm/damon/tests/core-kunit.h
@@ -318,9 +318,8 @@ static void damon_test_split_regions_of(struct kunit *test)
 	}
 	damon_split_regions_of(t, 4, 5);
 	KUNIT_EXPECT_LE(test, damon_nr_regions(t), 12u);
-	damon_for_each_region(r, t) {
+	damon_for_each_region(r, t)
 		KUNIT_EXPECT_GE(test, damon_sz_region(r) % 5ul, 0ul);
-	}
 	damon_free_target(t);
 }
 
-- 
2.47.3

[PATCH v2 5/5] mm/damon/tests/core-kunit: remove a redundant test case and add a new test case in damos_test_commit_quota_goal()

[Shu Anzai]

Remove a redundant test case from damos_test_commit_quota_goal() 
as it is already covered. Instead, add a new test for 
DAMOS_QUOTA_SOME_MEM_PSI_US, which was previously not tested.

Signed-off-by: Shu Anzai <shu17az@gmail.com>
---
 mm/damon/tests/core-kunit.h | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/mm/damon/tests/core-kunit.h b/mm/damon/tests/core-kunit.h
index 36622a2c11f1..4bf1d172436b 100644
--- a/mm/damon/tests/core-kunit.h
+++ b/mm/damon/tests/core-kunit.h
@@ -601,9 +601,10 @@ static void damos_test_commit_quota_goal(struct kunit *test)
 			});
 	damos_test_commit_quota_goal_for(test, &dst,
 			&(struct damos_quota_goal) {
-			.metric = DAMOS_QUOTA_USER_INPUT,
-			.target_value = 789,
-			.current_value = 12,
+			.metric = DAMOS_QUOTA_SOME_MEM_PSI_US,
+			.target_value = 234,
+			.current_value = 345,
+			.last_psi_total = 567,
 			});
 }
 
-- 
2.43.0

Re: [PATCH v2 5/5] mm/damon/tests/core-kunit: remove a redundant test case and add a new test case in damos_test_commit_quota_goal()

[SeongJae Park]

On Wed, 24 Dec 2025 04:22:00 +0000 Shu Anzai <shu17az@gmail.com> wrote:

> Remove a redundant test case from damos_test_commit_quota_goal() 
> as it is already covered. Instead, add a new test for 
> DAMOS_QUOTA_SOME_MEM_PSI_US, which was previously not tested.
> 
> Signed-off-by: Shu Anzai <shu17az@gmail.com>
> ---
>  mm/damon/tests/core-kunit.h | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/mm/damon/tests/core-kunit.h b/mm/damon/tests/core-kunit.h
> index 36622a2c11f1..4bf1d172436b 100644
> --- a/mm/damon/tests/core-kunit.h
> +++ b/mm/damon/tests/core-kunit.h
> @@ -601,9 +601,10 @@ static void damos_test_commit_quota_goal(struct kunit *test)
>  			});
>  	damos_test_commit_quota_goal_for(test, &dst,
>  			&(struct damos_quota_goal) {
> -			.metric = DAMOS_QUOTA_USER_INPUT,
> -			.target_value = 789,
> -			.current_value = 12,
> +			.metric = DAMOS_QUOTA_SOME_MEM_PSI_US,
> +			.target_value = 234,
> +			.current_value = 345,
> +			.last_psi_total = 567,
>  			});
>  }
>  
> -- 
> 2.43.0

Reviewed-by: SeongJae Park <sj@kernel.org>


Thanks,
SJ

Re: [PATCH v2 0/5] mm/damon/tests/core-kunit: extend existing test scenarios

[SeongJae Park]

On Wed, 24 Dec 2025 04:21:55 +0000 Shu Anzai <shu17az@gmail.com> wrote:

> Improve the KUnit test coverage for DAMON. 
> 
> The five patches in this series respectively extend damon_test_split_at(), 
> damon_test_merge_two(), damon_test_merge_regions_of(), 
> damon_test_split_regions_of(), and damos_test_commit_quota_goal().
> 
> Changes from v1:
> - Split the original patch into five smaller patches.
> - Remove a newly added region from damon_test_merge_regions_of() 
>   to avoid an obvious test case.
> - Restore the test case in damon_test_split_regions_of() 
>   that was previously removed.

Thank you for revisioning, Shu!

> 
> Shu Anzai (5):
>   mm/damon/tests/core-kunit: verify the 'age' field in
>     damon_test_split_at()
>   mm/damon/tests/core-kunit: verify the 'age' and 'nr_accesses_bp'
>     fields in damon_test_merge_two()
>   mm/damon/tests/core-kunit: add a test case for region merge size limit
>     in damon_test_merge_regions_of()
>   mm/damon/tests/core-kunit: add test cases for multiple regions in
>     damon_test_split_regions_of()

I left a trivial comment on this fourth patch for unnecessary braces enclosing
a single statement.  Other than that, all look good to me.

>   mm/damon/tests/core-kunit: remove a redundant test case and add a new
>     test case in damos_test_commit_quota_goal()
> 
>  mm/damon/tests/core-kunit.h | 50 +++++++++++++++++++++++++++++--------
>  1 file changed, 39 insertions(+), 11 deletions(-)
> 
> -- 
> 2.43.0


Thanks,
SJ

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