[PATCH 00/12] mm/damon: cleanup code, add test cases, and update guidances in docs

[PATCH 00/12] mm/damon: cleanup code, add test cases, and update guidances in docs

[SJ Park]

Misc cleanup, improvements and updates of code, test, and documents.

Patches 1-5 cleanup DAMON code.  Patches 6-10 adds kunit and selftest
test cases for recently fixed bugs and a new feature.  Patches 11 and 12
update guidelines for AI review and what document to read, on DAMON
documents.

Changes from RFC v1.2
- RFC v1.2: https://lore.kernel.org/20260729140253.87753-1-sj@kernel.org
- Drop RFC tag.
- Rebase to latest mm-new.
Changes from RFC v1.1
- RFC v1.1: https://lore.kernel.org/20260729033751.131213-1-sj@kernel.org
- Fix a typo: s/alingment/alignment/.
- Add damon probes parameter validation cleanup (patches 4 and 5).
Changes from RFC
- RFC: https://lore.kernel.org/20260728052811.192712-1-sj@kernel.org
- Remove ctx parameter of __damon_va_init_regions().
- Fix damon_nr_samples_per_aggr() overflow kunit test.
- Rebase to the latest mm-new.

SJ Park (12):
  mm/damon/core: use damon_nr_samples_per_aggr() for max merge threshold
  mm/damon/core: remove debug messages
  mm/damon/vaddr: remove a debug message
  mm/damon/core: validate number of probes in valid_probe_params()
  mm/damon/sysfs: remove probes number validation
  mm/damon/tests/core-kunit: extend set_regions() test for error case
  mm/damon/tests/core-kunit: test <=0 size damon_set_regions() inputs
  mm/damon/tests/core-kunit: test overlapping ranges for set_regions()
  mm/damon/tests/core-kunit: test damon_nr_samples_per_aggr()
  selftests/damon/sysfs.sh: test hugepage_mem_bp quota goal
  Docs/mm/damon/maintainer-profile: update AI review for Sashiko replies
  Docs/ABI/damon: recommend subsystem doc instead of admin-guide

 .../ABI/testing/sysfs-kernel-mm-damon         |  2 +-
 Documentation/mm/damon/maintainer-profile.rst | 19 ++----
 mm/damon/core.c                               | 19 +++---
 mm/damon/sysfs.c                              |  2 +-
 mm/damon/tests/core-kunit.h                   | 65 ++++++++++++++++---
 mm/damon/vaddr.c                              | 16 +----
 tools/testing/selftests/damon/sysfs.sh        |  1 +
 7 files changed, 76 insertions(+), 48 deletions(-)


base-commit: 52315e1a031f7370a286d6f6c805e2c8eab5abbc
-- 
2.47.3

[PATCH 01/12] mm/damon/core: use damon_nr_samples_per_aggr() for max merge threshold

[SJ Park]

kdamond_merge_regions() open-codes max region merge threshold
calculation.  What it does is fundamentally the same as
damon_nr_samples_per_aggr() but missing a few corner cases.  The
unhandled corner cases should be rare and make only a negligible level
of monitoring results degradation.  But having the inconsistency could
increase future maintenance burden.  Use the dedicated function.

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

diff --git a/mm/damon/core.c b/mm/damon/core.c
index f748acd6bbd5b..846da6df5b552 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -3509,8 +3509,7 @@ static void kdamond_merge_regions(struct damon_ctx *c, unsigned int threshold,
 	unsigned int max_thres;
 	bool count_age = true;
 
-	max_thres = c->attrs.aggr_interval /
-		(c->attrs.sample_interval ?  c->attrs.sample_interval : 1);
+	max_thres = damon_nr_samples_per_aggr(&c->attrs);
 	while (true) {
 		nr_regions = 0;
 		damon_for_each_target(t, c) {
-- 
2.47.3

[PATCH 02/12] mm/damon/core: remove debug messages

[SJ Park]

There are a few debug messages in DAMON core.  Those have not really
been used in a meaningful way for the last few years, though.  Remove
those.

Signed-off-by: SJ Park <sj@kernel.org>
---
 mm/damon/core.c | 9 ---------
 1 file changed, 9 deletions(-)

diff --git a/mm/damon/core.c b/mm/damon/core.c
index 846da6df5b552..4d28eb033fc4a 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -3732,10 +3732,6 @@ static unsigned long damos_wmark_wait_us(struct damos *scheme)
 
 	/* higher than high watermark or lower than low watermark */
 	if (metric > scheme->wmarks.high || scheme->wmarks.low > metric) {
-		if (scheme->wmarks.activated)
-			pr_debug("deactivate a scheme (%d) for %s wmark\n",
-				 scheme->action,
-				 str_high_low(metric > scheme->wmarks.high));
 		scheme->wmarks.activated = false;
 		return scheme->wmarks.interval;
 	}
@@ -3745,8 +3741,6 @@ static unsigned long damos_wmark_wait_us(struct damos *scheme)
 			!scheme->wmarks.activated)
 		return scheme->wmarks.interval;
 
-	if (!scheme->wmarks.activated)
-		pr_debug("activate a scheme (%d)\n", scheme->action);
 	scheme->wmarks.activated = true;
 	return 0;
 }
@@ -3889,8 +3883,6 @@ static int kdamond_fn(void *data)
 	struct damon_ctx *ctx = data;
 	unsigned long sz_limit = 0;
 
-	pr_debug("kdamond (%d) starts\n", current->pid);
-
 	mutex_lock(&ctx->call_controls_lock);
 	ctx->call_controls_obsolete = false;
 	mutex_unlock(&ctx->call_controls_lock);
@@ -4044,7 +4036,6 @@ static int kdamond_fn(void *data)
 	mutex_unlock(&ctx->walk_control_lock);
 	damos_walk_cancel(ctx);
 
-	pr_debug("kdamond (%d) finishes\n", current->pid);
 	mutex_lock(&ctx->kdamond_lock);
 	ctx->kdamond = NULL;
 	mutex_unlock(&ctx->kdamond_lock);
-- 
2.47.3

[PATCH 03/12] mm/damon/vaddr: remove a debug message

[SJ Park]

There is a debug message in the DAMON virtual address space operation
set.  It has not really been used in a meaningful way for the last few
years, though.  Remove it.

Signed-off-by: SJ Park <sj@kernel.org>
---
 mm/damon/vaddr.c | 16 +++-------------
 1 file changed, 3 insertions(+), 13 deletions(-)

diff --git a/mm/damon/vaddr.c b/mm/damon/vaddr.c
index c8c32b2ae0402..f884d3f78f30a 100644
--- a/mm/damon/vaddr.c
+++ b/mm/damon/vaddr.c
@@ -189,22 +189,12 @@ static int damon_va_three_regions(struct damon_target *t,
  *   <BIG UNMAPPED REGION 2>
  *   <stack>
  */
-static void __damon_va_init_regions(struct damon_ctx *ctx,
-				     struct damon_target *t)
+static void __damon_va_init_regions(struct damon_target *t)
 {
-	struct damon_target *ti;
 	struct damon_addr_range regions[3];
-	int tidx = 0;
 
-	if (damon_va_three_regions(t, regions)) {
-		damon_for_each_target(ti, ctx) {
-			if (ti == t)
-				break;
-			tidx++;
-		}
-		pr_debug("Failed to get three regions of %dth target\n", tidx);
+	if (damon_va_three_regions(t, regions))
 		return;
-	}
 
 	damon_set_regions(t, regions, 3, DAMON_MIN_REGION_SZ);
 }
@@ -217,7 +207,7 @@ static void damon_va_init(struct damon_ctx *ctx)
 	damon_for_each_target(t, ctx) {
 		/* the user may set the target regions as they want */
 		if (!damon_nr_regions(t))
-			__damon_va_init_regions(ctx, t);
+			__damon_va_init_regions(t);
 	}
 }
 
-- 
2.47.3

[PATCH 04/12] mm/damon/core: validate number of probes in valid_probe_params()

[SJ Park]

Each DAMON context is allowed to have only up to DAMON_MAX_PROBES
probes.  The central place for validating DAMON probe parameters,
damon_valid_probe_params(), is not validating the upper limit, though.
Do the validation.

Signed-off-by: SJ Park <sj@kernel.org>
---
 mm/damon/core.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/mm/damon/core.c b/mm/damon/core.c
index 4d28eb033fc4a..c010f686d033e 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -1420,6 +1420,13 @@ static bool damon_valid_probe_params(struct damon_ctx *ctx)
 	unsigned char max_probe_hits;
 	struct damon_probe *probe;
 	unsigned int wsum, wsum_to_add;
+	int nr_probes;
+
+	nr_probes = 0;
+	damon_for_each_probe(probe, ctx)
+		nr_probes++;
+	if (nr_probes > DAMON_MAX_PROBES)
+		return false;
 
 	if (!damon_has_probe_weights(ctx))
 		return true;
-- 
2.47.3

[PATCH 05/12] mm/damon/sysfs: remove probes number validation

[SJ Park]

DAMON sysfs interface is disallowing >DAMON_MAX_PROBES nr_probes input,
since DAMON_MAX_PROBES is the upper limit of probes per DAMON context.
The core layer is validating the upper limit again, though.  It is
preferred to let DAMON API callers such as sysfs interface to set
parameters in flexible ways, and do parameters validation in the core
layer.  Drop the duplicated validation in the sysfs interface.

Signed-off-by: SJ Park <sj@kernel.org>
---
 mm/damon/sysfs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c
index 7ec14f48d157a..b576e97cbfdb8 100644
--- a/mm/damon/sysfs.c
+++ b/mm/damon/sysfs.c
@@ -1479,7 +1479,7 @@ static ssize_t nr_probes_store(struct kobject *kobj,
 
 	if (err)
 		return err;
-	if (nr < 0 || nr > DAMON_MAX_PROBES)
+	if (nr < 0)
 		return -EINVAL;
 
 	probes = container_of(kobj, struct damon_sysfs_probes, kobj);
-- 
2.47.3

[PATCH 06/12] mm/damon/tests/core-kunit: extend set_regions() test for error case

[SJ Park]

damon_test_set_regions_for() is designed to test only success-expected
damon_set_regions() calls.  Extend it to cover error-expected calls,
too.

Signed-off-by: SJ Park <sj@kernel.org>
---
 mm/damon/tests/core-kunit.h | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/mm/damon/tests/core-kunit.h b/mm/damon/tests/core-kunit.h
index af26b3d60957b..2bcf3bafe2e29 100644
--- a/mm/damon/tests/core-kunit.h
+++ b/mm/damon/tests/core-kunit.h
@@ -469,11 +469,12 @@ static void damon_test_set_regions_for(struct kunit *test,
 		struct damon_addr_range *old_ranges, int sz_old_ranges,
 		struct damon_addr_range *new_ranges, int sz_new_ranges,
 		unsigned long min_region_sz,
-		struct damon_addr_range *expect_ranges, int sz_expect_ranges)
+		struct damon_addr_range *expect_ranges, int sz_expect_ranges,
+		int expect_err)
 {
 	struct damon_target *t;
 	struct damon_region *r;
-	int i;
+	int i, err;
 
 	t = damon_new_target();
 	if (!t)
@@ -487,7 +488,8 @@ static void damon_test_set_regions_for(struct kunit *test,
 		damon_add_region(r, t);
 	}
 
-	damon_set_regions(t, new_ranges, sz_new_ranges, min_region_sz);
+	err = damon_set_regions(t, new_ranges, sz_new_ranges, min_region_sz);
+	KUNIT_EXPECT_EQ(test, err, expect_err);
 
 	KUNIT_EXPECT_EQ(test, damon_nr_regions(t), sz_expect_ranges);
 	if (damon_nr_regions(t) != sz_expect_ranges) {
@@ -516,7 +518,7 @@ static void damon_test_set_regions(struct kunit *test)
 			(struct damon_addr_range[]){
 			{.start = 5, .end = 15},
 			{.start = 15, .end = 25},
-			}, 2);
+			}, 2, 0);
 	/* Un-intersecting regions should be removed. */
 	damon_test_set_regions_for(test,
 			(struct damon_addr_range[]){
@@ -529,7 +531,7 @@ static void damon_test_set_regions(struct kunit *test)
 			1,
 			(struct damon_addr_range[]){
 			{.start = 18, .end = 23},
-			}, 1);
+			}, 1, 0);
 	/*
 	 * Holes should be filled up with new regions.
 	 *
@@ -550,7 +552,7 @@ static void damon_test_set_regions(struct kunit *test)
 			{.start = 8, .end = 16},
 			{.start = 16, .end = 24},
 			{.start = 24, .end = 28},
-			}, 3);
+			}, 3, 0);
 	/*
 	 * New regions should be able to be appended.
 	 *
@@ -572,7 +574,7 @@ static void damon_test_set_regions(struct kunit *test)
 			{.start = 0, .end = 4},
 			{.start = 4, .end = 15},
 			{.start = 25, .end = 40},
-			}, 3);
+			}, 3, 0);
 	/*
 	 * New regions should be able to be inserted.
 	 *
@@ -595,7 +597,7 @@ static void damon_test_set_regions(struct kunit *test)
 			{.start = 0, .end = 15},
 			{.start = 25, .end = 40},
 			{.start = 44, .end = 50},
-			}, 3);
+			}, 3, 0);
 }
 
 static void damon_test_update_monitoring_result(struct kunit *test)
-- 
2.47.3

[PATCH 07/12] mm/damon/tests/core-kunit: test <=0 size damon_set_regions() inputs

[SJ Park]

Commit 1292c0ecb1ca ("mm/damon/core: validate ranges in
damon_set_regions()") disallowed passing zero or negative size input
ranges to damon_set_regions().  Add kunit test cases for those inputs.

Signed-off-by: SJ Park <sj@kernel.org>
---
 mm/damon/tests/core-kunit.h | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/mm/damon/tests/core-kunit.h b/mm/damon/tests/core-kunit.h
index 2bcf3bafe2e29..3cbbbcbfbef8f 100644
--- a/mm/damon/tests/core-kunit.h
+++ b/mm/damon/tests/core-kunit.h
@@ -598,6 +598,20 @@ static void damon_test_set_regions(struct kunit *test)
 			{.start = 25, .end = 40},
 			{.start = 44, .end = 50},
 			}, 3, 0);
+	/* Zero size regions should return -EINVAL. */
+	damon_test_set_regions_for(test,
+			(struct damon_addr_range[]){}, 0,
+			(struct damon_addr_range[]){
+			{.start = 42, .end = 42},
+			}, 1, 1,
+			(struct damon_addr_range[]){}, 0, -EINVAL);
+	/* Negative size regions should return -EINVAL. */
+	damon_test_set_regions_for(test,
+			(struct damon_addr_range[]){}, 0,
+			(struct damon_addr_range[]){
+			{.start = 42, .end = 21},
+			}, 1, 1,
+			(struct damon_addr_range[]){}, 0, -EINVAL);
 }
 
 static void damon_test_update_monitoring_result(struct kunit *test)
-- 
2.47.3

[PATCH 08/12] mm/damon/tests/core-kunit: test overlapping ranges for set_regions()

[SJ Park]

Commit 954157679ec3 ("mm/damon/core: disallow overlapping input ranges
for damon_set_regions()") disallowed passing overlapping input ranges to
damon_set_regions().  Add a kunit test case for the overlapping input.

Signed-off-by: SJ Park <sj@kernel.org>
---
 mm/damon/tests/core-kunit.h | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/mm/damon/tests/core-kunit.h b/mm/damon/tests/core-kunit.h
index 3cbbbcbfbef8f..a4164ac489a61 100644
--- a/mm/damon/tests/core-kunit.h
+++ b/mm/damon/tests/core-kunit.h
@@ -612,6 +612,17 @@ static void damon_test_set_regions(struct kunit *test)
 			{.start = 42, .end = 21},
 			}, 1, 1,
 			(struct damon_addr_range[]){}, 0, -EINVAL);
+	/*
+	 * Regions resulting in same region after alignment should return
+	 * -EINVAL.
+	 */
+	damon_test_set_regions_for(test,
+			(struct damon_addr_range[]){}, 0,
+			(struct damon_addr_range[]){
+			{.start = 10, .end = 20},
+			{.start = 20, .end = 30},
+			}, 2, 4096,
+			(struct damon_addr_range[]){}, 0, -EINVAL);
 }
 
 static void damon_test_update_monitoring_result(struct kunit *test)
-- 
2.47.3

[PATCH 09/12] mm/damon/tests/core-kunit: test damon_nr_samples_per_aggr()

[SJ Park]

damon_max_nr_accesses(), which is a previous version of
damon_nr_samples_per_aggr() before the renaming, was wrongly returning
zero or random overflowed values for extreme intervals setup.  Commit
35d4a3cf70a8 ("mm/damon/ops-common: handle extreme intervals in
damon_hot_score()") updated the function to return correct or more valid
values.  Add a kunit test to ensure it is working as expected.

Signed-off-by: SJ Park <sj@kernel.org>
---
 mm/damon/tests/core-kunit.h | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/mm/damon/tests/core-kunit.h b/mm/damon/tests/core-kunit.h
index a4164ac489a61..d0bed01a5b7fe 100644
--- a/mm/damon/tests/core-kunit.h
+++ b/mm/damon/tests/core-kunit.h
@@ -625,6 +625,27 @@ static void damon_test_set_regions(struct kunit *test)
 			(struct damon_addr_range[]){}, 0, -EINVAL);
 }
 
+static void damon_test_nr_samples_per_aggr(struct kunit *test)
+{
+	struct damon_attrs attrs = {
+		.sample_interval = 0,
+		.aggr_interval = 0,
+	};
+
+	/* Zero aggregation interval doesn't cause division by zero */
+	KUNIT_EXPECT_EQ(test, damon_nr_samples_per_aggr(&attrs), 1);
+
+	/*
+	 * Too large aggregation interval on 64 bit system doesn't cause
+	 * overflow
+	 */
+	if (ULONG_MAX > UINT_MAX) {
+		attrs.aggr_interval = (unsigned long)UINT_MAX + 1;
+		KUNIT_EXPECT_EQ(test, damon_nr_samples_per_aggr(&attrs),
+				UINT_MAX);
+	}
+}
+
 static void damon_test_update_monitoring_result(struct kunit *test)
 {
 	struct damon_attrs old_attrs = {
@@ -1736,6 +1757,7 @@ static struct kunit_case damon_test_cases[] = {
 	KUNIT_CASE(damon_test_split_above_half_progresses),
 	KUNIT_CASE(damon_test_ops_registration),
 	KUNIT_CASE(damon_test_set_regions),
+	KUNIT_CASE(damon_test_nr_samples_per_aggr),
 	KUNIT_CASE(damon_test_update_monitoring_result),
 	KUNIT_CASE(damon_test_set_attrs),
 	KUNIT_CASE(damon_test_mvsum),
-- 
2.47.3

[PATCH 10/12] selftests/damon/sysfs.sh: test hugepage_mem_bp quota goal

[SJ Park]

DAMON sysfs quota goal target_metric file now accepts 'hugepage_mem_bp'
input.  Test it is accepted in fundamental DAMON sysfs file operation
selftest.

Signed-off-by: SJ Park <sj@kernel.org>
---
 tools/testing/selftests/damon/sysfs.sh | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/testing/selftests/damon/sysfs.sh b/tools/testing/selftests/damon/sysfs.sh
index ddebde6edabe4..b66593c9ac471 100755
--- a/tools/testing/selftests/damon/sysfs.sh
+++ b/tools/testing/selftests/damon/sysfs.sh
@@ -210,6 +210,7 @@ test_goal()
 	ensure_write_succ "$fpath" "active_mem_bp" "valid input"
 	ensure_write_succ "$fpath" "inactive_mem_bp" "valid input"
 	ensure_write_succ "$fpath" "node_eligible_mem_bp" "valid input"
+	ensure_write_succ "$fpath" "hugepage_mem_bp" "valid input"
 	ensure_write_fail "$fpath" "foo" "invalid input"
 	ensure_file "$goal_dir/nid" "exist" "600"
 	ensure_file "$goal_dir/path" "exist" "600"
-- 
2.47.3

[PATCH 11/12] Docs/mm/damon/maintainer-profile: update AI review for Sashiko replies

[SJ Park]

In the past, sharing Sashiko review results was tedious.  Also it was
suggested to minimize the recipients on the sharing mails.  Hence the AI
review section of DAMON maintainer profile document was updated to give
guidance about available tools for making the sharing easier, and how
the recipients list should be managed.

Now DAMON is onboarded [1] to Sashiko's automatic review replies
feature.  Sashiko directly sends its reviews as replies to the patch
mail thread. It also reduces the recipients list to deliver the
reporting to only the author and the mailing list.

Remove the old guidance that is no more necessary but only confusing.

[1] https://github.com/sashiko-dev/sashiko/commit/b554c7b6e733

Signed-off-by: SJ Park <sj@kernel.org>
---
 Documentation/mm/damon/maintainer-profile.rst | 19 +++++--------------
 1 file changed, 5 insertions(+), 14 deletions(-)

diff --git a/Documentation/mm/damon/maintainer-profile.rst b/Documentation/mm/damon/maintainer-profile.rst
index fb2fa00cc9aa1..a7c1352339378 100644
--- a/Documentation/mm/damon/maintainer-profile.rst
+++ b/Documentation/mm/damon/maintainer-profile.rst
@@ -106,18 +106,9 @@ AI Review
 
 For patches that are publicly posted to DAMON mailing list
 (damon@lists.linux.dev), AI reviews of the patches will be available at
-sashiko.dev.  The reviews could also be sent as mails to the author of the
-patch.
-
-Patch authors are encouraged to check the AI reviews and share their opinions.
-The sharing could be done as a reply to the mail thread.  Consider reducing the
-recipients list for such sharing, since some people are not really interested
-in AI reviews.  As a rule of thumb, drop stable@vger.kernel.org and individuals
-except DAMON maintainer.
-
-`hkml` also provides a `feature
-<https://github.com/sjp38/hackermail/blob/master/USAGE.md#forwarding-sashikodev-statuscomments-to-mailing-list>`_
-for such sharing.  Please feel free to use the feature.
+sashiko.dev.  The reviews will also be sent as replies to the author of the
+patch and the mailing list.
 
-It is only an optional recommendation.  DAMON maintainer could also ask any
-question about the AI reviews, though.
+Patch authors are encouraged to check the AI reviews and share their opinions
+by replying on the mail thread.  It is only an optional recommendation.  DAMON
+maintainer could also ask any question about the AI reviews, though.
-- 
2.47.3

[PATCH 12/12] Docs/ABI/damon: recommend subsystem doc instead of admin-guide

[SJ Park]

DAMON ABI doc is recommending DAMON admin-guide for people who are
willing to know further about DAMON.  Nowadays the subsystem doc
(Documentation/mm/damon) is a more recommended place for even beginners.
Recommend the subsystem doc over admin-guide.

Signed-off-by: SJ Park <sj@kernel.org>
---
 Documentation/ABI/testing/sysfs-kernel-mm-damon | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Documentation/ABI/testing/sysfs-kernel-mm-damon b/Documentation/ABI/testing/sysfs-kernel-mm-damon
index f8d2601e82904..ad21f58f3c912 100644
--- a/Documentation/ABI/testing/sysfs-kernel-mm-damon
+++ b/Documentation/ABI/testing/sysfs-kernel-mm-damon
@@ -3,7 +3,7 @@ Date:		Mar 2022
 Contact:	SJ Park <sj@kernel.org>
 Description:	Interface for Data Access MONitoring (DAMON).  Contains files
 		for controlling DAMON.  For more details on DAMON itself,
-		please refer to Documentation/admin-guide/mm/damon/index.rst.
+		please refer to Documentation/mm/damon/index.rst.
 
 What:		/sys/kernel/mm/damon/admin/
 Date:		Mar 2022
-- 
2.47.3

Re: [PATCH 02/12] mm/damon/core: remove debug messages

[SJ Park]

On Tue,  1 Sep 2026 22:47:35 -0700 SJ Park <sj@kernel.org> wrote:

> There are a few debug messages in DAMON core.  Those have not really
> been used in a meaningful way for the last few years, though.  Remove
> those.

Hi Andrew,


Sashiko found with this patch, string_choices.h can also be excluded.  It is
the only finding.  I guess reposting entire series for the small change is too
much?  Could you please add below attaching fixup patch when you pick this?
Let me know if you prefer reposting.


Thanks,
SJ

=== >8 ===
From b9c86e50efd30bab8c5cb99b3063bd823184b033 Mon Sep 17 00:00:00 2001
From: SJ Park <sj@kernel.org>
Date: Tue, 1 Sep 2026 23:08:16 -0700
Subject: [PATCH] mm/damon/core: remove string_choices.h include

It is no more being used.

Signed-off-by: SJ Park <sj@kernel.org>
---
 mm/damon/core.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/mm/damon/core.c b/mm/damon/core.c
index a7ed7724c85af..84f6bc634f377 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -15,7 +15,6 @@
 #include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/string.h>
-#include <linux/string_choices.h>

 /* for damon_get_folio() used by node eligible memory metrics */
 #include "ops-common.h"
--
2.47.3

Re: [PATCH 00/12] mm/damon: cleanup code, add test cases, and update guidances in docs

[SJ Park]

On Tue,  1 Sep 2026 22:47:33 -0700 SJ Park <sj@kernel.org> wrote:

> Misc cleanup, improvements and updates of code, test, and documents.

Sashiko found one better-to-do change for patch 2.  Since it is quite trivial
in my opinion, I asked Andrew to pick a fixup patch as a reply to the patch 2.
Andrew, please feel free to let me know if you prefer reposting.

Sashiko sent findings to damon@ mailing list [1], and I replied to all the
comments having some findings.  Please read those for details.

[1] https://lore.kernel.org/damon/


Thanks,
SJ

[...]

Re: [PATCH 05/12] mm/damon/sysfs: remove probes number validation

[Kunwu Chan]

On Tue,  1 Sep 2026 22:47:38 -0700 SJ Park <sj@kernel.org> wrote:

> DAMON sysfs interface is disallowing >DAMON_MAX_PROBES nr_probes input,
> since DAMON_MAX_PROBES is the upper limit of probes per DAMON context.
> The core layer is validating the upper limit again, though.  It is
> preferred to let DAMON API callers such as sysfs interface to set
> parameters in flexible ways, and do parameters validation in the core
> layer.  Drop the duplicated validation in the sysfs interface.
> 
> Signed-off-by: SJ Park <sj@kernel.org>
> ---
>  mm/damon/sysfs.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c
> index 7ec14f48d157a..b576e97cbfdb8 100644
> --- a/mm/damon/sysfs.c
> +++ b/mm/damon/sysfs.c
> @@ -1479,7 +1479,7 @@ static ssize_t nr_probes_store(struct kobject *kobj,
>  
>  	if (err)
>  		return err;
> -	if (nr < 0 || nr > DAMON_MAX_PROBES)
> +	if (nr < 0)

Hi SJ,

Thanks for the cleanup.

I was wondering whether DAMON_MAX_PROBES is purely a core invariant
or also an interface constraint.

With this change, sysfs allows nr_probes larger than
DAMON_MAX_PROBES and damon_sysfs_probes_add_dirs() will start creating
probe objects before the configuration is later rejected by
damon_valid_probe_params().

Since nr_probes directly controls the number of sysfs objects created,
do we still want to keep an early check here?

I agree that the core validation is required for non-sysfs callers,
but I am not sure whether this particular limit should be duplicated
at the sysfs layer.

Thanks,
Kunwu


>  		return -EINVAL;
>  
>  	probes = container_of(kobj, struct damon_sysfs_probes, kobj);
> -- 
> 2.47.3
> 

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Re: [PATCH 05/12] mm/damon/sysfs: remove probes number validation

[SJ Park]

On Wed,  2 Sep 2026 22:07:13 +0800 Kunwu Chan <kunwu.chan@gmail.com> wrote:

> On Tue,  1 Sep 2026 22:47:38 -0700 SJ Park <sj@kernel.org> wrote:
[...]
> I was wondering whether DAMON_MAX_PROBES is purely a core invariant
> or also an interface constraint.

Thank you for reviewing my patch and raising this question!

> 
> With this change, sysfs allows nr_probes larger than
> DAMON_MAX_PROBES and damon_sysfs_probes_add_dirs() will start creating
> probe objects before the configuration is later rejected by
> damon_valid_probe_params().
> 
> Since nr_probes directly controls the number of sysfs objects created,
> do we still want to keep an early check here?
> 
> I agree that the core validation is required for non-sysfs callers,
> but I am not sure whether this particular limit should be duplicated
> at the sysfs layer.

I agree the user experience may be not that good.

In my humble opinion, however, keeping code simplicity is more important than
the user experience here.  After all, DAMON_SYSFS is recommended to be used by
another high level tools like DAMON user-space tool (damo) rather than human
fingers.  The user-space tools like damo can do the early check.

Please feel free to let me know if you have any other opinions or questions.


Thanks,
SJ

[...]

Re: [PATCH 09/12] mm/damon/tests/core-kunit: test damon_nr_samples_per_aggr()

[Kunwu Chan]

On Tue,  1 Sep 2026 22:47:42 -0700 SJ Park <sj@kernel.org> wrote:

> damon_max_nr_accesses(), which is a previous version of
> damon_nr_samples_per_aggr() before the renaming, was wrongly returning
> zero or random overflowed values for extreme intervals setup.  Commit
> 35d4a3cf70a8 ("mm/damon/ops-common: handle extreme intervals in
> damon_hot_score()") updated the function to return correct or more valid
> values.  Add a kunit test to ensure it is working as expected.
> 
> Signed-off-by: SJ Park <sj@kernel.org>
> ---
>  mm/damon/tests/core-kunit.h | 22 ++++++++++++++++++++++
>  1 file changed, 22 insertions(+)
> 
> diff --git a/mm/damon/tests/core-kunit.h b/mm/damon/tests/core-kunit.h
> index a4164ac489a61..d0bed01a5b7fe 100644
> --- a/mm/damon/tests/core-kunit.h
> +++ b/mm/damon/tests/core-kunit.h
> @@ -625,6 +625,27 @@ static void damon_test_set_regions(struct kunit *test)
>  			(struct damon_addr_range[]){}, 0, -EINVAL);
>  }
>  
> +static void damon_test_nr_samples_per_aggr(struct kunit *test)
> +{
> +	struct damon_attrs attrs = {
> +		.sample_interval = 0,
> +		.aggr_interval = 0,
> +	};
> +

Hi SJ,

A small question about the first test case.

Both `sample_interval` and `aggr_interval` are zero here.  Since
`sample_interval` is the denominator in `damon_nr_samples_per_aggr()`,
would it be better to keep `aggr_interval` non-zero when testing the
zero `sample_interval` case?

This would make the test explicitly cover the divide-by-zero protection.
If the `aggr_interval == 0` behavior is also worth covering, perhaps it
could be tested separately.

Thanks,
Kunwu


> +	/* Zero aggregation interval doesn't cause division by zero */
> +	KUNIT_EXPECT_EQ(test, damon_nr_samples_per_aggr(&attrs), 1);
> +
> +	/*
> +	 * Too large aggregation interval on 64 bit system doesn't cause
> +	 * overflow
> +	 */
> +	if (ULONG_MAX > UINT_MAX) {
> +		attrs.aggr_interval = (unsigned long)UINT_MAX + 1;
> +		KUNIT_EXPECT_EQ(test, damon_nr_samples_per_aggr(&attrs),
> +				UINT_MAX);
> +	}
> +}
> +
>  static void damon_test_update_monitoring_result(struct kunit *test)
>  {
>  	struct damon_attrs old_attrs = {
> @@ -1736,6 +1757,7 @@ static struct kunit_case damon_test_cases[] = {
>  	KUNIT_CASE(damon_test_split_above_half_progresses),
>  	KUNIT_CASE(damon_test_ops_registration),
>  	KUNIT_CASE(damon_test_set_regions),
> +	KUNIT_CASE(damon_test_nr_samples_per_aggr),
>  	KUNIT_CASE(damon_test_update_monitoring_result),
>  	KUNIT_CASE(damon_test_set_attrs),
>  	KUNIT_CASE(damon_test_mvsum),
> -- 
> 2.47.3
> 

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Re: [PATCH 09/12] mm/damon/tests/core-kunit: test damon_nr_samples_per_aggr()

[SJ Park]

On Wed,  2 Sep 2026 23:08:41 +0800 Kunwu Chan <kunwu.chan@gmail.com> wrote:

> On Tue,  1 Sep 2026 22:47:42 -0700 SJ Park <sj@kernel.org> wrote:
[...]
> Both `sample_interval` and `aggr_interval` are zero here.  Since
> `sample_interval` is the denominator in `damon_nr_samples_per_aggr()`,
> would it be better to keep `aggr_interval` non-zero when testing the
> zero `sample_interval` case?
> 
> This would make the test explicitly cover the divide-by-zero protection.
> If the `aggr_interval == 0` behavior is also worth covering, perhaps it
> could be tested separately.

Thank you for your review and question, Kunwu!

Yes, that kind of additional test case would be nice.  Please feel free to post
a patch if you'd like to! :)  And no pressure, no rush.  I will also consider
doing it myself if it seems you are not interested.


Thanks,
SJ

[...]

Re: [PATCH 04/12] mm/damon/core: validate number of probes in valid_probe_params()

[Kunwu Chan]

On Tue,  1 Sep 2026 22:47:37 -0700 SJ Park <sj@kernel.org> wrote:

> Each DAMON context is allowed to have only up to DAMON_MAX_PROBES
> probes.  The central place for validating DAMON probe parameters,
> damon_valid_probe_params(), is not validating the upper limit, though.
> Do the validation.
> 
> Signed-off-by: SJ Park <sj@kernel.org>
> ---
>  mm/damon/core.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/mm/damon/core.c b/mm/damon/core.c
> index 4d28eb033fc4a..c010f686d033e 100644
> --- a/mm/damon/core.c
> +++ b/mm/damon/core.c
> @@ -1420,6 +1420,13 @@ static bool damon_valid_probe_params(struct damon_ctx *ctx)
>  	unsigned char max_probe_hits;
>  	struct damon_probe *probe;
>  	unsigned int wsum, wsum_to_add;
> +	int nr_probes;
> +
> +	nr_probes = 0;
> +	damon_for_each_probe(probe, ctx)
> +		nr_probes++;
> +	if (nr_probes > DAMON_MAX_PROBES)
> +		return false;

Hi SJ,

Thanks for the explanation.

I agree that `DAMON_MAX_PROBES` is better enforced in the core layer,
so that all callers share the same validation path without duplicating
the limit in the sysfs layer.

Reviewed-by: Kunwu Chan <kunwu.chan@gmail.com>

Thanks,
Kunwu

>  
>  	if (!damon_has_probe_weights(ctx))
>  		return true;
> -- 
> 2.47.3
> 

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Re: [PATCH 05/12] mm/damon/sysfs: remove probes number validation

[Kunwu Chan]

On Wed,  2 Sep 2026 07:37:06 -0700 SJ Park <sj@kernel.org> wrote:

> On Wed,  2 Sep 2026 22:07:13 +0800 Kunwu Chan <kunwu.chan@gmail.com> wrote:
> 
> > On Tue,  1 Sep 2026 22:47:38 -0700 SJ Park <sj@kernel.org> wrote:
> [...]
> > I was wondering whether DAMON_MAX_PROBES is purely a core invariant
> > or also an interface constraint.
> 
> Thank you for reviewing my patch and raising this question!
> 
> > 
> > With this change, sysfs allows nr_probes larger than
> > DAMON_MAX_PROBES and damon_sysfs_probes_add_dirs() will start creating
> > probe objects before the configuration is later rejected by
> > damon_valid_probe_params().
> > 
> > Since nr_probes directly controls the number of sysfs objects created,
> > do we still want to keep an early check here?
> > 
> > I agree that the core validation is required for non-sysfs callers,
> > but I am not sure whether this particular limit should be duplicated
> > at the sysfs layer.
> 
> I agree the user experience may be not that good.
> 
> In my humble opinion, however, keeping code simplicity is more important than
> the user experience here.  After all, DAMON_SYSFS is recommended to be used by
> another high level tools like DAMON user-space tool (damo) rather than human
> fingers.  The user-space tools like damo can do the early check.
> 
> Please feel free to let me know if you have any other opinions or questions.

Hi SJ,

Thanks for the explanation.

I agree that keeping the invariant validation in the core layer avoids
duplicating the limit in multiple places.  Your point about DAMON_SYSFS
being mainly consumed by higher-level tools like damo also makes sense.

My concern was mainly about the temporary creation of sysfs probe objects
before the configuration is rejected, rather than the user-facing error
message.  Given that the number of probes is bounded by the core
invariant anyway, I agree that keeping the validation centralized is a
reasonable trade-off.

Thanks for clarifying.

Reviewed-by: Kunwu Chan <kunwu.chan@gmail.com>

Thanks,
Kunwu

> 
> 
> Thanks,
> SJ
> 
> [...]
> 

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Re: [PATCH 09/12] mm/damon/tests/core-kunit: test damon_nr_samples_per_aggr()

[Kunwu Chan]

On Wed,  2 Sep 2026 08:19:54 -0700 SJ Park <sj@kernel.org> wrote:

> On Wed,  2 Sep 2026 23:08:41 +0800 Kunwu Chan <kunwu.chan@gmail.com> wrote:
> 
> > On Tue,  1 Sep 2026 22:47:42 -0700 SJ Park <sj@kernel.org> wrote:
> [...]
> > Both `sample_interval` and `aggr_interval` are zero here.  Since
> > `sample_interval` is the denominator in `damon_nr_samples_per_aggr()`,
> > would it be better to keep `aggr_interval` non-zero when testing the
> > zero `sample_interval` case?
> > 
> > This would make the test explicitly cover the divide-by-zero protection.
> > If the `aggr_interval == 0` behavior is also worth covering, perhaps it
> > could be tested separately.
> 
> Thank you for your review and question, Kunwu!
> 
> Yes, that kind of additional test case would be nice.  Please feel free to post
> a patch if you'd like to! :)  And no pressure, no rush.  I will also consider
> doing it myself if it seems you are not interested.

Thanks for the feedback, SJ!

I will prepare a small follow-up patch for this test
clarity improvement.

Reviewed-by: Kunwu Chan <kunwu.chan@gmail.com>

Thanks,
Kunwu

> 
> 
> Thanks,
> SJ
> 
> [...]
> 

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Re: [PATCH 00/12] mm/damon: cleanup code, add test cases, and update guidances in docs

[Andrew Morton]

On Tue,  1 Sep 2026 22:47:33 -0700 SJ Park <sj@kernel.org> wrote:

> Misc cleanup, improvements and updates of code, test, and documents.
> 
> Patches 1-5 cleanup DAMON code.  Patches 6-10 adds kunit and selftest
> test cases for recently fixed bugs and a new feature.  Patches 11 and 12
> update guidelines for AI review and what document to read, on DAMON
> documents.

Thanks, I added all this.  Along with the fixup for [02/12].

Re: [PATCH 09/12] mm/damon/tests/core-kunit: test damon_nr_samples_per_aggr()

[SJ Park]

On Wed,  2 Sep 2026 23:49:42 +0800 Kunwu Chan <kunwu.chan@gmail.com> wrote:

> On Wed,  2 Sep 2026 08:19:54 -0700 SJ Park <sj@kernel.org> wrote:
> 
> > On Wed,  2 Sep 2026 23:08:41 +0800 Kunwu Chan <kunwu.chan@gmail.com> wrote:
> > 
> > > On Tue,  1 Sep 2026 22:47:42 -0700 SJ Park <sj@kernel.org> wrote:
> > [...]
> > > Both `sample_interval` and `aggr_interval` are zero here.  Since
> > > `sample_interval` is the denominator in `damon_nr_samples_per_aggr()`,
> > > would it be better to keep `aggr_interval` non-zero when testing the
> > > zero `sample_interval` case?
> > > 
> > > This would make the test explicitly cover the divide-by-zero protection.
> > > If the `aggr_interval == 0` behavior is also worth covering, perhaps it
> > > could be tested separately.
> > 
> > Thank you for your review and question, Kunwu!
> > 
> > Yes, that kind of additional test case would be nice.  Please feel free to post
> > a patch if you'd like to! :)  And no pressure, no rush.  I will also consider
> > doing it myself if it seems you are not interested.
> 
> Thanks for the feedback, SJ!
> 
> I will prepare a small follow-up patch for this test
> clarity improvement.

Looking forward to!

> 
> Reviewed-by: Kunwu Chan <kunwu.chan@gmail.com>

Thank you!  Also appreciate your R-b: for other patches!


Thanks,
SJ

[...]

Re: [PATCH 01/12] mm/damon/core: use damon_nr_samples_per_aggr() for max merge threshold

[Kunwu Chan]

On Tue,  1 Sep 2026 22:47:34 -0700 SJ Park <sj@kernel.org> wrote:

> kdamond_merge_regions() open-codes max region merge threshold
> calculation.  What it does is fundamentally the same as
> damon_nr_samples_per_aggr() but missing a few corner cases.  The
> unhandled corner cases should be rare and make only a negligible level
> of monitoring results degradation.  But having the inconsistency could
> increase future maintenance burden.  Use the dedicated function.
> 
> Signed-off-by: SJ Park <sj@kernel.org>
> ---
>  mm/damon/core.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/mm/damon/core.c b/mm/damon/core.c
> index f748acd6bbd5b..846da6df5b552 100644
> --- a/mm/damon/core.c
> +++ b/mm/damon/core.c
> @@ -3509,8 +3509,7 @@ static void kdamond_merge_regions(struct damon_ctx *c, unsigned int threshold,
>  	unsigned int max_thres;
>  	bool count_age = true;
>  
> -	max_thres = c->attrs.aggr_interval /
> -		(c->attrs.sample_interval ?  c->attrs.sample_interval : 1);
> +	max_thres = damon_nr_samples_per_aggr(&c->attrs);

The helper replacement makes sense to me, and it also keeps 
the corner-case handling centralized.


Reviewed-by: Kunwu Chan <kunwu.chan@gmail.com>

Thanks,
Kunwu


>  	while (true) {
>  		nr_regions = 0;
>  		damon_for_each_target(t, c) {
> -- 
> 2.47.3
> 

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Re: [PATCH 03/12] mm/damon/vaddr: remove a debug message

[Kunwu Chan]

On Tue,  1 Sep 2026 22:47:36 -0700 SJ Park <sj@kernel.org> wrote:

> There is a debug message in the DAMON virtual address space operation
> set.  It has not really been used in a meaningful way for the last few
> years, though.  Remove it.
> 
> Signed-off-by: SJ Park <sj@kernel.org>
> ---
>  mm/damon/vaddr.c | 16 +++-------------
>  1 file changed, 3 insertions(+), 13 deletions(-)
> 
> diff --git a/mm/damon/vaddr.c b/mm/damon/vaddr.c
> index c8c32b2ae0402..f884d3f78f30a 100644
> --- a/mm/damon/vaddr.c
> +++ b/mm/damon/vaddr.c
> @@ -189,22 +189,12 @@ static int damon_va_three_regions(struct damon_target *t,
>   *   <BIG UNMAPPED REGION 2>
>   *   <stack>
>   */
> -static void __damon_va_init_regions(struct damon_ctx *ctx,
> -				     struct damon_target *t)
> +static void __damon_va_init_regions(struct damon_target *t)
>  {
> -	struct damon_target *ti;
>  	struct damon_addr_range regions[3];
> -	int tidx = 0;
>  
> -	if (damon_va_three_regions(t, regions)) {
> -		damon_for_each_target(ti, ctx) {

Thanks for the cleanup. The debug message was the only user of
ctx here, so the signature cleanup follows naturally.

Reviewed-by: Kunwu Chan <kunwu.chan@gmail.com>

Thanks,
Kunwu

> -			if (ti == t)
> -				break;
> -			tidx++;
> -		}
> -		pr_debug("Failed to get three regions of %dth target\n", tidx);
> +	if (damon_va_three_regions(t, regions))
>  		return;
> -	}
>  
>  	damon_set_regions(t, regions, 3, DAMON_MIN_REGION_SZ);
>  }
> @@ -217,7 +207,7 @@ static void damon_va_init(struct damon_ctx *ctx)
>  	damon_for_each_target(t, ctx) {
>  		/* the user may set the target regions as they want */
>  		if (!damon_nr_regions(t))
> -			__damon_va_init_regions(ctx, t);
> +			__damon_va_init_regions(t);
>  	}
>  }
>  
> -- 
> 2.47.3
> 

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Re: [PATCH 08/12] mm/damon/tests/core-kunit: test overlapping ranges for set_regions()

[Kunwu Chan]

On Tue,  1 Sep 2026 22:47:41 -0700 SJ Park <sj@kernel.org> wrote:

> Commit 954157679ec3 ("mm/damon/core: disallow overlapping input ranges
> for damon_set_regions()") disallowed passing overlapping input ranges to
> damon_set_regions().  Add a kunit test case for the overlapping input.
> 
> Signed-off-by: SJ Park <sj@kernel.org>
> ---
>  mm/damon/tests/core-kunit.h | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/mm/damon/tests/core-kunit.h b/mm/damon/tests/core-kunit.h
> index 3cbbbcbfbef8f..a4164ac489a61 100644
> --- a/mm/damon/tests/core-kunit.h
> +++ b/mm/damon/tests/core-kunit.h
> @@ -612,6 +612,17 @@ static void damon_test_set_regions(struct kunit *test)
>  			{.start = 42, .end = 21},
>  			}, 1, 1,
>  			(struct damon_addr_range[]){}, 0, -EINVAL);
> +	/*
> +	 * Regions resulting in same region after alignment should return
> +	 * -EINVAL.
> +	 */
> +	damon_test_set_regions_for(test,
> +			(struct damon_addr_range[]){}, 0,
> +			(struct damon_addr_range[]){
> +			{.start = 10, .end = 20},
> +			{.start = 20, .end = 30},
> +			}, 2, 4096,
> +			(struct damon_addr_range[]){}, 0, -EINVAL);
>  }
>  
>  static void damon_test_update_monitoring_result(struct kunit *test)
> -- 
> 2.47.3
> 

Hi SJ,

I reviewed patches 6-8. The test helper extension and the added
error cases look correct to me, including the overlap case after
range alignment.

Reviewed-by: Kunwu Chan <kunwu.chan@gmail.com>

Thanks,
Kunwu


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Re: [PATCH 10/12] selftests/damon/sysfs.sh: test hugepage_mem_bp quota goal

[Kunwu Chan]

On Tue,  1 Sep 2026 22:47:43 -0700 SJ Park <sj@kernel.org> wrote:

> DAMON sysfs quota goal target_metric file now accepts 'hugepage_mem_bp'
> input.  Test it is accepted in fundamental DAMON sysfs file operation
> selftest.
> 
> Signed-off-by: SJ Park <sj@kernel.org>
> ---
>  tools/testing/selftests/damon/sysfs.sh | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/tools/testing/selftests/damon/sysfs.sh b/tools/testing/selftests/damon/sysfs.sh
> index ddebde6edabe4..b66593c9ac471 100755
> --- a/tools/testing/selftests/damon/sysfs.sh
> +++ b/tools/testing/selftests/damon/sysfs.sh
> @@ -210,6 +210,7 @@ test_goal()
>  	ensure_write_succ "$fpath" "active_mem_bp" "valid input"
>  	ensure_write_succ "$fpath" "inactive_mem_bp" "valid input"
>  	ensure_write_succ "$fpath" "node_eligible_mem_bp" "valid input"
> +	ensure_write_succ "$fpath" "hugepage_mem_bp" "valid input"
>  	ensure_write_fail "$fpath" "foo" "invalid input"
>  	ensure_file "$goal_dir/nid" "exist" "600"
>  	ensure_file "$goal_dir/path" "exist" "600"
> -- 
> 2.47.3
> 

The added test correctly covers the
hugepage_mem_bp quota goal.

Reviewed-by: Kunwu Chan <kunwu.chan@gmail.com>

Thanks,
Kunwu

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Re: [PATCH 12/12] Docs/ABI/damon: recommend subsystem doc instead of admin-guide

[Kunwu Chan]

On Tue,  1 Sep 2026 22:47:45 -0700 SJ Park <sj@kernel.org> wrote:

> DAMON ABI doc is recommending DAMON admin-guide for people who are
> willing to know further about DAMON.  Nowadays the subsystem doc
> (Documentation/mm/damon) is a more recommended place for even beginners.
> Recommend the subsystem doc over admin-guide.
> 
> Signed-off-by: SJ Park <sj@kernel.org>
> ---
>  Documentation/ABI/testing/sysfs-kernel-mm-damon | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/Documentation/ABI/testing/sysfs-kernel-mm-damon b/Documentation/ABI/testing/sysfs-kernel-mm-damon
> index f8d2601e82904..ad21f58f3c912 100644
> --- a/Documentation/ABI/testing/sysfs-kernel-mm-damon
> +++ b/Documentation/ABI/testing/sysfs-kernel-mm-damon
> @@ -3,7 +3,7 @@ Date:		Mar 2022
>  Contact:	SJ Park <sj@kernel.org>
>  Description:	Interface for Data Access MONitoring (DAMON).  Contains files
>  		for controlling DAMON.  For more details on DAMON itself,
> -		please refer to Documentation/admin-guide/mm/damon/index.rst.
> +		please refer to Documentation/mm/damon/index.rst.
>  
>  What:		/sys/kernel/mm/damon/admin/
>  Date:		Mar 2022
> -- 
> 2.47.3
> 

Reviewed-by: Kunwu Chan <kunwu.chan@gmail.com>

Thanks,
Kunwu

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