[PATCH 00/11] mm/damon: update, optimize, and clean up doc, tests, and code

[PATCH 00/11] mm/damon: update, optimize, and clean up doc, tests, and code

[SJ Park]

Patches 1 and 2 update the design and ABI documents for recently added
DAMON features.  Patches 3-7 add or update more unit and self tests for
DAMON to cover recently changed or added functions and sysfs files.
Patch 8 optimizes damon_commit_target_regions() to skip unnecessary
adjacent ranges setup.  Patches 9-11 clean and fix up recently added
DAMON sysfs interface code for readability.

Changes from RFC v1.3
- RFC v1.3: https://lore.kernel.org/20260626001644.85825-1-sj@kernel.org
- Drop RFC tag.
- Rebase to latest mm-new.
Changes from RFC v1.2
- RFC v1.2: https://lore.kernel.org/20260625142357.103500-1-sj@kernel.org
- Fix broken sphinx syntax in patch 1.
- Drop unused counts[] for damon_rand() test in patch 3.
Changes from RFC v1.1
- RFC v1.1: https://lore.kernel.org/20260625050756.91115-1-sj@kernel.org
- Document nid requirement for node_eligible_mem_bp.
- Fix typos: s/memmcg/memcg/, s/geets/gets/.
- Drop damon_rnd() randomness test case; test boundness only.
- Fixup dests dir selftest to do real test with correct file permission
  checks.
Changes from RFC
- RFC: https://lore.kernel.org/20260624142008.87180-1-sj@kernel.org
- Rebase directly to latest mm-new.

SJ Park (11):
  Docs/mm/damon/design: update for DAMOS_QUOTA_NODE_ELIGIBLE_MEM_BP
  Docs/ABI/damon: document probe files
  mm/damon/tests/core-kunit: test damon_rand()
  selftests/damon/sysfs.sh: test multiple probe dirs creation
  selftests/damon/sysfs.sh: test {core,ops}_filters/ directories
  selftests/damon/sysfs.sh: test dests dir
  selftests/damon/sysfs.sh: test all files in quota goal dir
  mm/damon/core: reduce range setup in damon_commit_target_regions()
  mm/damon/sysfs: split probe setup function out
  mm/damon/sysfs: split out filters setup function
  mm/damon/sysfs: fix typos in probe_{add,rm}_dirs: s/attr/probe/

 .../ABI/testing/sysfs-kernel-mm-damon         |  40 +++++++
 Documentation/mm/damon/design.rst             |   6 +-
 mm/damon/core.c                               |  22 +++-
 mm/damon/sysfs.c                              | 102 ++++++++++--------
 mm/damon/tests/core-kunit.h                   |  15 +++
 tools/testing/selftests/damon/sysfs.sh        |  71 +++++++++++-
 6 files changed, 203 insertions(+), 53 deletions(-)


base-commit: bb5dde77be397d614ef968578e3bf6cf9674df3c
-- 
2.47.3

[PATCH 03/11] mm/damon/tests/core-kunit: test damon_rand()

[SJ Park]

Commit 9012c4e647df ("mm/damon: replace damon_rand() with a per-ctx
lockless PRNG") optimized DAMON for better performance.  Add a kunit
test for ensuring the bounds of the output.

Signed-off-by: SJ Park <sj@kernel.org>
---
 mm/damon/tests/core-kunit.h | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/mm/damon/tests/core-kunit.h b/mm/damon/tests/core-kunit.h
index aef7e0553cba4..0124f83b39b83 100644
--- a/mm/damon/tests/core-kunit.h
+++ b/mm/damon/tests/core-kunit.h
@@ -1547,6 +1547,20 @@ static void damon_test_walk_control_obsolete(struct kunit *test)
 	damon_destroy_ctx(ctx);
 }
 
+static void damon_test_rand(struct kunit *test)
+{
+	struct damon_ctx ctx;
+	int i;
+
+	prandom_seed_state(&ctx.rnd_state, get_random_u64());
+	for (i = 0; i < 10000; i++) {
+		unsigned long rnd = damon_rand(&ctx, 0, 10);
+
+		KUNIT_EXPECT_GE(test, rnd, 0);
+		KUNIT_EXPECT_LE(test, rnd, 9);
+	}
+}
+
 static struct kunit_case damon_test_cases[] = {
 	KUNIT_CASE(damon_test_target),
 	KUNIT_CASE(damon_test_regions),
@@ -1578,6 +1592,7 @@ static struct kunit_case damon_test_cases[] = {
 	KUNIT_CASE(damon_test_apply_min_nr_regions),
 	KUNIT_CASE(damon_test_is_last_region),
 	KUNIT_CASE(damon_test_walk_control_obsolete),
+	KUNIT_CASE(damon_test_rand),
 	{},
 };
 
-- 
2.47.3

[PATCH 04/11] selftests/damon/sysfs.sh: test multiple probe dirs creation

[SJ Park]

DAMON sysfs essential file operations test (sysfs.sh) was extended to
test DAMON probes sysfs directory, by commit 14885da09b0f
("selftests/damon/sysfs.sh: test probes dir").  Unlike other DAMON sysfs
files, it is testing only a single directory case.  Extend it for
multiple directories.

Signed-off-by: SJ Park <sj@kernel.org>
---
 tools/testing/selftests/damon/sysfs.sh | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/tools/testing/selftests/damon/sysfs.sh b/tools/testing/selftests/damon/sysfs.sh
index 2eaaa5ae3c5ed..d528dfea44c3b 100755
--- a/tools/testing/selftests/damon/sysfs.sh
+++ b/tools/testing/selftests/damon/sysfs.sh
@@ -346,8 +346,13 @@ test_probes()
 	ensure_write_succ "$probes_dir/nr_probes" "1" "valid input"
 	test_probe "$probes_dir/0"
 
+	ensure_write_succ "$probes_dir/nr_probes" "2" "valid input"
+	test_probe "$probes_dir/0"
+	test_probe "$probes_dir/1"
+
 	ensure_write_succ "$probes_dir/nr_probes" "0" "valid input"
 	ensure_dir "$probes_dir/0" "not_exist"
+	ensure_dir "$probes_dir/1" "not_exist"
 }
 
 test_monitoring_attrs()
-- 
2.47.3

[PATCH 05/11] selftests/damon/sysfs.sh: test {core,ops}_filters/ directories

[SJ Park]

DAMON sysfs interface essential file operations test (sysf.sh) is not
testing DAMOS {core,ops}_filters directories.  Add the tests.

Signed-off-by: SJ Park <sj@kernel.org>
---
 tools/testing/selftests/damon/sysfs.sh | 28 ++++++++++++++++++++++----
 1 file changed, 24 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/damon/sysfs.sh b/tools/testing/selftests/damon/sysfs.sh
index d528dfea44c3b..78eea0d13c271 100755
--- a/tools/testing/selftests/damon/sysfs.sh
+++ b/tools/testing/selftests/damon/sysfs.sh
@@ -103,10 +103,28 @@ test_filter()
 {
 	filter_dir=$1
 	ensure_file "$filter_dir/type" "exist" "600"
-	ensure_write_succ "$filter_dir/type" "anon" "valid input"
-	ensure_write_succ "$filter_dir/type" "memcg" "valid input"
-	ensure_write_succ "$filter_dir/type" "addr" "valid input"
-	ensure_write_succ "$filter_dir/type" "target" "valid input"
+
+	local dir_name=$(basename "$(dirname "$filter_dir")")
+	if  [ "$dir_name" = "filters" ] || [ "$dir_name" = "ops_filters" ]
+	then
+		ensure_write_succ "$filter_dir/type" "anon" "valid input"
+		ensure_write_succ "$filter_dir/type" "memcg" "valid input"
+	fi
+	if  [ "$dir_name" = "filters" ] || [ "$dir_name" = "core_filters" ]
+	then
+		ensure_write_succ "$filter_dir/type" "addr" "valid input"
+		ensure_write_succ "$filter_dir/type" "target" "valid input"
+	fi
+	if [ "$dir_name" = "core_filters" ]
+	then
+		ensure_write_fail "$filter_dir/type" "anon" "ops type"
+		ensure_write_fail "$filter_dir/type" "memcg" "ops type"
+	fi
+	if [ "$dir_name"  = "ops_filters" ]
+	then
+		ensure_write_fail "$filter_dir/type" "addr" "core type"
+		ensure_write_fail "$filter_dir/type" "target" "core type"
+	fi
 	ensure_write_fail "$filter_dir/type" "foo" "invalid input"
 	ensure_file "$filter_dir/matching" "exist" "600"
 	ensure_file "$filter_dir/memcg_path" "exist" "600"
@@ -208,6 +226,8 @@ test_scheme()
 	test_quotas "$scheme_dir/quotas"
 	test_watermarks "$scheme_dir/watermarks"
 	test_filters "$scheme_dir/filters"
+	test_filters "$scheme_dir/core_filters"
+	test_filters "$scheme_dir/ops_filters"
 	test_stats "$scheme_dir/stats"
 	test_tried_regions "$scheme_dir/tried_regions"
 }
-- 
2.47.3

[PATCH 06/11] selftests/damon/sysfs.sh: test dests dir

[SJ Park]

DAMON selftest interface essential file operations test (sysfs.sh) is
not testing DAMOS dests/ directory.  Add the test.

Signed-off-by: SJ Park <sj@kernel.org>
---
 tools/testing/selftests/damon/sysfs.sh | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/tools/testing/selftests/damon/sysfs.sh b/tools/testing/selftests/damon/sysfs.sh
index 78eea0d13c271..f8d2092be004d 100755
--- a/tools/testing/selftests/damon/sysfs.sh
+++ b/tools/testing/selftests/damon/sysfs.sh
@@ -99,6 +99,29 @@ test_stats()
 	done
 }
 
+test_dest()
+{
+	dest_dir=$1
+	ensure_file "$dest_dir/id" "exist" "600"
+	ensure_file "$dest_dir/weight" "exist" "600"
+}
+
+test_dests()
+{
+	dests_dir=$1
+	ensure_file "$dests_dir/nr_dests" "exist" "600"
+	ensure_write_succ "$dests_dir/nr_dests" "1" "valid input"
+	test_dest "$dests_dir/0"
+
+	ensure_write_succ "$dests_dir/nr_dests" "2" "valid input"
+	test_dest "$dests_dir/0"
+	test_dest "$dests_dir/1"
+
+	ensure_write_succ "$dests_dir/nr_dests" "0" "valid input"
+	ensure_dir "$dests_dir/0" "not_exist"
+	ensure_dir "$dests_dir/1" "not_exist"
+}
+
 test_filter()
 {
 	filter_dir=$1
@@ -225,6 +248,7 @@ test_scheme()
 	ensure_file "$scheme_dir/apply_interval_us" "exist" "600"
 	test_quotas "$scheme_dir/quotas"
 	test_watermarks "$scheme_dir/watermarks"
+	test_dests "$scheme_dir/dests"
 	test_filters "$scheme_dir/filters"
 	test_filters "$scheme_dir/core_filters"
 	test_filters "$scheme_dir/ops_filters"
-- 
2.47.3

[PATCH 07/11] selftests/damon/sysfs.sh: test all files in quota goal dir

[SJ Park]

DAMON sysfs interface for DAMOS quota has quite extended since its
initial introduction.  The test case for that in DAMON sysfs interface
essential file operations test (sysfs.sh) has not accordingly extended,
though.  Extend the test case to test all existing files.

Signed-off-by: SJ Park <sj@kernel.org>
---
 tools/testing/selftests/damon/sysfs.sh | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/tools/testing/selftests/damon/sysfs.sh b/tools/testing/selftests/damon/sysfs.sh
index f8d2092be004d..b43deee60fe95 100755
--- a/tools/testing/selftests/damon/sysfs.sh
+++ b/tools/testing/selftests/damon/sysfs.sh
@@ -199,6 +199,20 @@ test_goal()
 	ensure_dir "$goal_dir" "exist"
 	ensure_file "$goal_dir/target_value" "exist" "600"
 	ensure_file "$goal_dir/current_value" "exist" "600"
+	ensure_file "$goal_dir/target_metric" "exist" "600"
+	local fpath="$goal_dir/target_metric"
+	ensure_write_succ "$fpath" "user_input" "valid input"
+	ensure_write_succ "$fpath" "some_mem_psi_us" "valid input"
+	ensure_write_succ "$fpath" "node_mem_used_bp" "valid input"
+	ensure_write_succ "$fpath" "node_mem_free_bp" "valid input"
+	ensure_write_succ "$fpath" "node_memcg_used_bp" "valid input"
+	ensure_write_succ "$fpath" "node_memcg_free_bp" "valid input"
+	ensure_write_succ "$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_fail "$fpath" "foo" "invalid input"
+	ensure_file "$goal_dir/nid" "exist" "600"
+	ensure_file "$goal_dir/path" "exist" "600"
 }
 
 test_goals()
-- 
2.47.3

Re: [PATCH 00/11] mm/damon: update, optimize, and clean up doc, tests, and code

[SJ Park]

On Tue, 30 Jun 2026 07:17:14 -0700 SJ Park <sj@kernel.org> wrote:

> Patches 1 and 2 update the design and ABI documents for recently added
> DAMON features.  Patches 3-7 add or update more unit and self tests for
> DAMON to cover recently changed or added functions and sysfs files.
> Patch 8 optimizes damon_commit_target_regions() to skip unnecessary
> adjacent ranges setup.  Patches 9-11 clean and fix up recently added
> DAMON sysfs interface code for readability.

Sashiko found a few things that could be good future works, but none of those
is a blocker of this series, in my opinion.  Please read the full thread [1] in
lore.kernel.org if you want more details of Sashiko findings and my replies.

[1] https://lore.kernel.org/20260630141726.92246-1-sj@kernel.org


THanks,
SJ

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