[RFC PATCH 00/13] Extedn DAMOS filters for address ranges and

[RFC PATCH 00/13] Extedn DAMOS filters for address ranges and

[SeongJae Park]

There are use cases that need to apply DAMOS schemes to specific address
ranges or DAMON monitoring targets.  NUMA nodes in the physical address
space, special memory objects in the virtual address space, and
monitoring target specific efficient monitoring results snapshot
retrieval could be examples of such use cases.  This patchset extends
DAMOS filters feature for such cases, by implementing two more filter
types, namely address ranges and DAMON monitoring types.

Patches sequence
----------------

The first seven patches are for the address ranges based DAMOS filter.
The first patch implements the filter feature and expose it via DAMON
kernel API.  The second patch further expose the feature to users via
DAMON sysfs interface.  The third and fourth patches implement unit
tests and selftests for the feature.  Three patches (fifth to seventh)
updating the documents follow.

The following six patches are for the DAMON monitoring target based
DAMOS filter.  The eighth patch implements the feature in the core layer
and expose it via DAMON's kernel API.  The ninth patch further expose it
to users via DAMON sysfs interface.  Tenth patch add a selftest, and two
patches (eleventh and twelfth) update documents.

SeongJae Park (13):
  mm/damon/core: introduce address range type damos filter
  mm/damon/sysfs-schemes: support address range type DAMOS filter
  mm/damon/core-test: add a unit test for __damos_filter_out()
  selftests/damon/sysfs: test address range damos filter
  Docs/mm/damon/design: update for address range filters
  Docs/ABI/damon: update for address range DAMOS filter
  Docs/admin-guide/mm/damon/usage: update for address range type DAMOS
    filter
  mm/damon/core: implement target type damos filter
  mm/damon/sysfs-schemes: support target damos filter
  selftests/damon/sysfs: test damon_target filter
  Docs/mm/damon/design: update for DAMON monitoring target type DAMOS
    filter
  Docs/ABI/damon: update for DAMON monitoring target type DAMOS filter
  Docs/admin-guide/mm/damon/usage: update for DAMON monitoring target
    type DAMOS filter

 .../ABI/testing/sysfs-kernel-mm-damon         | 27 +++++-
 Documentation/admin-guide/mm/damon/usage.rst  | 34 +++++---
 Documentation/mm/damon/design.rst             | 24 ++++--
 include/linux/damon.h                         | 28 +++++--
 mm/damon/core-test.h                          | 61 ++++++++++++++
 mm/damon/core.c                               | 62 ++++++++++++++
 mm/damon/sysfs-schemes.c                      | 83 +++++++++++++++++++
 tools/testing/selftests/damon/sysfs.sh        |  5 ++
 8 files changed, 299 insertions(+), 25 deletions(-)

-- 
2.25.1

[RFC PATCH 01/13] mm/damon/core: introduce address range type damos filter

[SeongJae Park]

Users can know special characteristic of specific address ranges.  NUMA
nodes or special objects or buffers in virtual address space could be
such examples.  For such cases, DAMOS schemes could required to be
applied to only specific address ranges.  Implement yet another type of
DAMOS filter for the purpose.

Note that the existing filter types, namely anon pages and memcg DAMOS
filters needed page level type check.  Because such check can be done
efficiently in the opertions set layer, those filters are handled in
operations set layer.  Specifically, only paddr operations set
implementation supports these filters.  Also, because statistics
counting is done in the DAMON core layer, the regions that filtered out
by these filters are counted as tried but failed to the statistics.

Unlike those, address range based filters can efficiently handled in the
core layer.  Hence, do the handling in the layer, and count the regions
that filtered out by those as the scheme has not tried for the region.
This difference should clearly documented.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 include/linux/damon.h | 22 +++++++++++++-----
 mm/damon/core.c       | 52 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 68 insertions(+), 6 deletions(-)

diff --git a/include/linux/damon.h b/include/linux/damon.h
index d5d4d19928e0..476f37a883a4 100644
--- a/include/linux/damon.h
+++ b/include/linux/damon.h
@@ -226,16 +226,24 @@ struct damos_stat {
  * enum damos_filter_type - Type of memory for &struct damos_filter
  * @DAMOS_FILTER_TYPE_ANON:	Anonymous pages.
  * @DAMOS_FILTER_TYPE_MEMCG:	Specific memcg's pages.
+ * @DAMOS_FILTER_TYPE_ADDR:	Address range.
  * @NR_DAMOS_FILTER_TYPES:	Number of filter types.
  *
- * The support of each filter type is up to running &struct damon_operations.
- * &enum DAMON_OPS_PADDR is supporting all filter types, while
- * &enum DAMON_OPS_VADDR and &enum DAMON_OPS_FVADDR are not supporting any
- * filter types.
+ * The anon pages type and memcg type filters are handled by underlying
+ * &struct damon_operations as a part of scheme action trying, and therefore
+ * accounted as 'tried'.  In contrast, other types are handled by core layer
+ * before trying of the action and therefore not accounted as 'tried'.
+ *
+ * The support of the filters that handled by &struct damon_operations depend
+ * on the running &struct damon_operations.
+ * &enum DAMON_OPS_PADDR supports both anon pages type and memcg type filters,
+ * while &enum DAMON_OPS_VADDR and &enum DAMON_OPS_FVADDR don't support any of
+ * the two types.
  */
 enum damos_filter_type {
 	DAMOS_FILTER_TYPE_ANON,
 	DAMOS_FILTER_TYPE_MEMCG,
+	DAMOS_FILTER_TYPE_ADDR,
 	NR_DAMOS_FILTER_TYPES,
 };
 
@@ -244,18 +252,20 @@ enum damos_filter_type {
  * @type:	Type of the page.
  * @matching:	If the matching page should filtered out or in.
  * @memcg_id:	Memcg id of the question if @type is DAMOS_FILTER_MEMCG.
+ * @addr_range:	Address range if @type is DAMOS_FILTER_TYPE_ADDR.
  * @list:	List head for siblings.
  *
  * Before applying the &damos->action to a memory region, DAMOS checks if each
  * page of the region matches to this and avoid applying the action if so.
- * Note that the check support is up to &struct damon_operations
- * implementation.
+ * Support of each filter type depends on the running &struct damon_operations
+ * and the type.  Refer to &enum damos_filter_type for more detai.
  */
 struct damos_filter {
 	enum damos_filter_type type;
 	bool matching;
 	union {
 		unsigned short memcg_id;
+		struct damon_addr_range addr_range;
 	};
 	struct list_head list;
 };
diff --git a/mm/damon/core.c b/mm/damon/core.c
index cbe5a1cc27c4..c061d289c832 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -906,6 +906,56 @@ static void damos_update_stat(struct damos *s,
 	s->stat.sz_applied += sz_applied;
 }
 
+static bool __damos_filter_out(struct damon_target *t, struct damon_region *r,
+		struct damos_filter *filter)
+{
+	bool matched = false;
+	unsigned long start, end;
+
+	switch (filter->type) {
+	case DAMOS_FILTER_TYPE_ADDR:
+		start = ALIGN_DOWN(filter->addr_range.start, DAMON_MIN_REGION);
+		end = ALIGN_DOWN(filter->addr_range.end, DAMON_MIN_REGION);
+
+		/* inside the range */
+		if (start <= r->ar.start && r->ar.end <= end) {
+			matched = true;
+			break;
+		}
+		/* outside of the range */
+		if (r->ar.end <= start || end <= r->ar.start) {
+			matched = false;
+			break;
+		}
+		/* start before the range and overlap */
+		if (r->ar.start < start) {
+			damon_split_region_at(t, r, start - r->ar.start);
+			matched = false;
+			break;
+		}
+		/* start inside the range */
+		damon_split_region_at(t, r, end - r->ar.start);
+		matched = true;
+		break;
+	default:
+		break;
+	}
+
+	return matched == filter->matching;
+}
+
+static bool damos_filter_out(struct damon_target *t, struct damon_region *r,
+		struct damos *s)
+{
+	struct damos_filter *filter;
+
+	damos_for_each_filter(filter, s) {
+		if (__damos_filter_out(t, r, filter))
+			return true;
+	}
+	return false;
+}
+
 static void damos_apply_scheme(struct damon_ctx *c, struct damon_target *t,
 		struct damon_region *r, struct damos *s)
 {
@@ -932,6 +982,8 @@ static void damos_apply_scheme(struct damon_ctx *c, struct damon_target *t,
 			}
 			damon_split_region_at(t, r, sz);
 		}
+		if (damos_filter_out(t, r, s))
+			return;
 		ktime_get_coarse_ts64(&begin);
 		if (c->callback.before_damos_apply)
 			err = c->callback.before_damos_apply(c, t, r, s);
-- 
2.25.1

[RFC PATCH 02/13] mm/damon/sysfs-schemes: support address range type DAMOS filter

[SeongJae Park]

Extend DAMON sysfs interface to support address range based DAMOS
filters, by adding a special keyword for the filter/<N>/type file,
namely 'addr', and two files under filter/<N>/ for specifying the start
and the end addresses of the range, namely 'addr_start' and 'addr_end'.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/sysfs-schemes.c | 56 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)

diff --git a/mm/damon/sysfs-schemes.c b/mm/damon/sysfs-schemes.c
index 9a015079f3a4..03ddba3e216d 100644
--- a/mm/damon/sysfs-schemes.c
+++ b/mm/damon/sysfs-schemes.c
@@ -282,6 +282,7 @@ struct damon_sysfs_scheme_filter {
 	enum damos_filter_type type;
 	bool matching;
 	char *memcg_path;
+	struct damon_addr_range addr_range;
 };
 
 static struct damon_sysfs_scheme_filter *damon_sysfs_scheme_filter_alloc(void)
@@ -293,6 +294,7 @@ static struct damon_sysfs_scheme_filter *damon_sysfs_scheme_filter_alloc(void)
 static const char * const damon_sysfs_scheme_filter_type_strs[] = {
 	"anon",
 	"memcg",
+	"addr",
 };
 
 static ssize_t type_show(struct kobject *kobj,
@@ -373,6 +375,44 @@ static ssize_t memcg_path_store(struct kobject *kobj,
 	return count;
 }
 
+static ssize_t addr_start_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	struct damon_sysfs_scheme_filter *filter = container_of(kobj,
+			struct damon_sysfs_scheme_filter, kobj);
+
+	return sysfs_emit(buf, "%lu\n", filter->addr_range.start);
+}
+
+static ssize_t addr_start_store(struct kobject *kobj,
+		struct kobj_attribute *attr, const char *buf, size_t count)
+{
+	struct damon_sysfs_scheme_filter *filter = container_of(kobj,
+			struct damon_sysfs_scheme_filter, kobj);
+	int err = kstrtoul(buf, 0, &filter->addr_range.start);
+
+	return err ? err : count;
+}
+
+static ssize_t addr_end_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	struct damon_sysfs_scheme_filter *filter = container_of(kobj,
+			struct damon_sysfs_scheme_filter, kobj);
+
+	return sysfs_emit(buf, "%lu\n", filter->addr_range.end);
+}
+
+static ssize_t addr_end_store(struct kobject *kobj,
+		struct kobj_attribute *attr, const char *buf, size_t count)
+{
+	struct damon_sysfs_scheme_filter *filter = container_of(kobj,
+			struct damon_sysfs_scheme_filter, kobj);
+	int err = kstrtoul(buf, 0, &filter->addr_range.end);
+
+	return err ? err : count;
+}
+
 static void damon_sysfs_scheme_filter_release(struct kobject *kobj)
 {
 	struct damon_sysfs_scheme_filter *filter = container_of(kobj,
@@ -391,10 +431,18 @@ static struct kobj_attribute damon_sysfs_scheme_filter_matching_attr =
 static struct kobj_attribute damon_sysfs_scheme_filter_memcg_path_attr =
 		__ATTR_RW_MODE(memcg_path, 0600);
 
+static struct kobj_attribute damon_sysfs_scheme_filter_addr_start_attr =
+		__ATTR_RW_MODE(addr_start, 0600);
+
+static struct kobj_attribute damon_sysfs_scheme_filter_addr_end_attr =
+		__ATTR_RW_MODE(addr_end, 0600);
+
 static struct attribute *damon_sysfs_scheme_filter_attrs[] = {
 	&damon_sysfs_scheme_filter_type_attr.attr,
 	&damon_sysfs_scheme_filter_matching_attr.attr,
 	&damon_sysfs_scheme_filter_memcg_path_attr.attr,
+	&damon_sysfs_scheme_filter_addr_start_attr.attr,
+	&damon_sysfs_scheme_filter_addr_end_attr.attr,
 	NULL,
 };
 ATTRIBUTE_GROUPS(damon_sysfs_scheme_filter);
@@ -1484,7 +1532,15 @@ static int damon_sysfs_set_scheme_filters(struct damos *scheme,
 				damos_destroy_filter(filter);
 				return err;
 			}
+		} else if (filter->type == DAMOS_FILTER_TYPE_ADDR) {
+			if (sysfs_filter->addr_range.end <
+					sysfs_filter->addr_range.start) {
+				damos_destroy_filter(filter);
+				return -EINVAL;
+			}
+			filter->addr_range = sysfs_filter->addr_range;
 		}
+
 		damos_add_filter(scheme, filter);
 	}
 	return 0;
-- 
2.25.1

[RFC PATCH 02/13] mm/damon/sysfs-schemes: support address range type DAMOS filter

[SeongJae Park]

Date: Sat, 22 Jul 2023 19:45:58 +0000
Subject: [RFC PATCH 03/13] mm/damon/core-test: add a unit test for
 __damos_filter_out()

Implement a kunit test for the core of address range DAMOS filter
handling, namely __damos_filter_out().  The test especially focus on
regions that overlap with given filter's target address range.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/core-test.h | 61 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 61 insertions(+)

diff --git a/mm/damon/core-test.h b/mm/damon/core-test.h
index bb07721909e1..44e925bbb094 100644
--- a/mm/damon/core-test.h
+++ b/mm/damon/core-test.h
@@ -341,6 +341,66 @@ static void damon_test_set_attrs(struct kunit *test)
 	KUNIT_EXPECT_EQ(test, damon_set_attrs(c, &invalid_attrs), -EINVAL);
 }
 
+static void damos_test_filter_out(struct kunit *test)
+{
+	struct damon_target *t;
+	struct damon_region *r, *r2;
+	struct damos_filter *f;
+
+	f = damos_new_filter(DAMOS_FILTER_TYPE_ADDR, true);
+	f->addr_range = (struct damon_addr_range){
+		.start = DAMON_MIN_REGION * 2, .end = DAMON_MIN_REGION * 6};
+
+	t = damon_new_target();
+	r = damon_new_region(DAMON_MIN_REGION * 3, DAMON_MIN_REGION * 5);
+	damon_add_region(r, t);
+
+	/* region in the range */
+	KUNIT_EXPECT_TRUE(test, __damos_filter_out(NULL, t, r, f));
+	KUNIT_EXPECT_EQ(test, damon_nr_regions(t), 1);
+
+	/* region before the range */
+	r->ar.start = DAMON_MIN_REGION * 1;
+	r->ar.end = DAMON_MIN_REGION * 2;
+	KUNIT_EXPECT_FALSE(test, __damos_filter_out(NULL, t, r, f));
+	KUNIT_EXPECT_EQ(test, damon_nr_regions(t), 1);
+
+	/* region after the range */
+	r->ar.start = DAMON_MIN_REGION * 6;
+	r->ar.end = DAMON_MIN_REGION * 8;
+	KUNIT_EXPECT_FALSE(test, __damos_filter_out(NULL, t, r, f));
+	KUNIT_EXPECT_EQ(test, damon_nr_regions(t), 1);
+
+	/* region started before the range */
+	r->ar.start = DAMON_MIN_REGION * 1;
+	r->ar.end = DAMON_MIN_REGION * 4;
+	KUNIT_EXPECT_FALSE(test, __damos_filter_out(NULL, t, r, f));
+	/* filter should have split the region */
+	KUNIT_EXPECT_EQ(test, r->ar.start, DAMON_MIN_REGION * 1);
+	KUNIT_EXPECT_EQ(test, r->ar.end, DAMON_MIN_REGION * 2);
+	KUNIT_EXPECT_EQ(test, damon_nr_regions(t), 2);
+	r2 = damon_next_region(r);
+	KUNIT_EXPECT_EQ(test, r2->ar.start, DAMON_MIN_REGION * 2);
+	KUNIT_EXPECT_EQ(test, r2->ar.end, DAMON_MIN_REGION * 4);
+	damon_destroy_region(r2, t);
+
+	/* region started in the range */
+	r->ar.start = DAMON_MIN_REGION * 2;
+	r->ar.end = DAMON_MIN_REGION * 8;
+	KUNIT_EXPECT_TRUE(test, __damos_filter_out(NULL, t, r, f));
+	/* filter should have split the region */
+	KUNIT_EXPECT_EQ(test, r->ar.start, DAMON_MIN_REGION * 2);
+	KUNIT_EXPECT_EQ(test, r->ar.end, DAMON_MIN_REGION * 6);
+	KUNIT_EXPECT_EQ(test, damon_nr_regions(t), 2);
+	r2 = damon_next_region(r);
+	KUNIT_EXPECT_EQ(test, r2->ar.start, DAMON_MIN_REGION * 6);
+	KUNIT_EXPECT_EQ(test, r2->ar.end, DAMON_MIN_REGION * 8);
+	damon_destroy_region(r2, t);
+
+	damon_free_target(t);
+	damos_free_filter(f);
+}
+
 static struct kunit_case damon_test_cases[] = {
 	KUNIT_CASE(damon_test_target),
 	KUNIT_CASE(damon_test_regions),
@@ -353,6 +413,7 @@ static struct kunit_case damon_test_cases[] = {
 	KUNIT_CASE(damon_test_set_regions),
 	KUNIT_CASE(damon_test_update_monitoring_result),
 	KUNIT_CASE(damon_test_set_attrs),
+	KUNIT_CASE(damos_test_filter_out),
 	{},
 };
 
-- 
2.25.1

[RFC PATCH 04/13] selftests/damon/sysfs: test address range damos filter

[SeongJae Park]

Add a selftest for checking existence of addr_{start,end} files under
DAMOS filter directory, and 'addr' damos filter type input of DAMON
sysfs interface.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 tools/testing/selftests/damon/sysfs.sh | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tools/testing/selftests/damon/sysfs.sh b/tools/testing/selftests/damon/sysfs.sh
index 967e27267549..5677cfd342fc 100644
--- a/tools/testing/selftests/damon/sysfs.sh
+++ b/tools/testing/selftests/damon/sysfs.sh
@@ -103,9 +103,12 @@ test_filter()
 	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_fail "$filter_dir/type" "foo" "invalid input"
 	ensure_file "$filter_dir/matching" "exist" "600"
 	ensure_file "$filter_dir/memcg_path" "exist" "600"
+	ensure_file "$filter_dir/addr_start" "exist" "600"
+	ensure_file "$filter_dir/addr_end" "exist" "600"
 }
 
 test_filters()
-- 
2.25.1

[RFC PATCH 05/13] Docs/mm/damon/design: update for address range filters

[SeongJae Park]

Update DAMON design document's DAMOS filters section for address range
DAMOS filters.  Because address range filters are handled by the core
layer and it makes difference in schemes tried regions and schemes
statistics, clearly describe it.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 Documentation/mm/damon/design.rst | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/Documentation/mm/damon/design.rst b/Documentation/mm/damon/design.rst
index 4bfdf1d30c4a..134912166f5a 100644
--- a/Documentation/mm/damon/design.rst
+++ b/Documentation/mm/damon/design.rst
@@ -380,12 +380,21 @@ number of filters for each scheme.  Each filter specifies the type of target
 memory, and whether it should exclude the memory of the type (filter-out), or
 all except the memory of the type (filter-in).
 
-As of this writing, anonymous page type and memory cgroup type are supported by
-the feature.  Some filter target types can require additional arguments.  For
-example, the memory cgroup filter type asks users to specify the file path of
-the memory cgroup for the filter.  Hence, users can apply specific schemes to
-only anonymous pages, non-anonymous pages, pages of specific cgroups, all pages
-excluding those of specific cgroups, and any combination of those.
+Currently, anonymous page, memory cgroup, and address range type filters are
+supported by the feature.  Some filter target types can require additional
+arguments.  For example, the memory cgroup filter type asks users to specify
+the file path of the memory cgroup for the filter, while the address range type
+asks the start and end addresses of the range.  Hence, users can apply specific
+schemes to only anonymous pages, non-anonymous pages, pages of specific
+cgroups, all pages excluding those of specific cgroups, pages in specific
+address range, and any combination of those.
+
+To handle filters efficiently, the address range type filter is handled by the
+core layer, while others are handled by operations set.  If a memory region is
+filtered by the core layer-handled filter, it is not counted as the scheme has
+tried to the region.  In contrast, if a memory regions is filtered by an
+operations set layer-handled filter, it is counted as the scheme has tried.
+The difference in accounting leads to changes in the statistics.
 
 
 Application Programming Interface
-- 
2.25.1

[RFC PATCH 06/13] Docs/ABI/damon: update for address range DAMOS filter

[SeongJae Park]

Update DAMON ABI document for address ranges type DAMOS filter files.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 .../ABI/testing/sysfs-kernel-mm-damon         | 20 +++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/Documentation/ABI/testing/sysfs-kernel-mm-damon b/Documentation/ABI/testing/sysfs-kernel-mm-damon
index 3d9aaa1cafa9..0bc074d4618c 100644
--- a/Documentation/ABI/testing/sysfs-kernel-mm-damon
+++ b/Documentation/ABI/testing/sysfs-kernel-mm-damon
@@ -271,8 +271,9 @@ What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/filters/
 Date:		Dec 2022
 Contact:	SeongJae Park <sj@kernel.org>
 Description:	Writing to and reading from this file sets and gets the type of
-		the memory of the interest.  'anon' for anonymous pages, or
-		'memcg' for specific memory cgroup can be written and read.
+		the memory of the interest.  'anon' for anonymous pages,
+		'memcg' for specific memory cgroup, or 'addr' for address range
+		(an open-ended interval) can be written and read.
 
 What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/filters/<F>/memcg_path
 Date:		Dec 2022
@@ -281,6 +282,21 @@ Description:	If 'memcg' is written to the 'type' file, writing to and
 		reading from this file sets and gets the path to the memory
 		cgroup of the interest.
 
+What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/filters/<F>/addr_start
+Date:		Jul 2023
+Contact:	SeongJae Park <sj@kernel.org>
+Description:	If 'addr' is written to the 'type' file, writing to or reading
+		from this file sets or gets the start address of the address
+		range for the filter.
+
+What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/filters/<F>/addr_end
+Date:		Jul 2023
+Contact:	SeongJae Park <sj@kernel.org>
+Description:	If 'addr' is written to the 'type' file, writing to or reading
+		from this file sets or gets the end address of the address
+		range for the filter.
+
+
 What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/filters/<F>/matching
 Date:		Dec 2022
 Contact:	SeongJae Park <sj@kernel.org>
-- 
2.25.1

[RFC PATCH 07/13] Docs/admin-guide/mm/damon/usage: update for address range type DAMOS filter

[SeongJae Park]

Update DAMON usage document for the newly added address range type DAMOS
filter.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 Documentation/admin-guide/mm/damon/usage.rst | 31 +++++++++++++-------
 1 file changed, 20 insertions(+), 11 deletions(-)

diff --git a/Documentation/admin-guide/mm/damon/usage.rst b/Documentation/admin-guide/mm/damon/usage.rst
index 1859dd6c3834..a9cb9949b796 100644
--- a/Documentation/admin-guide/mm/damon/usage.rst
+++ b/Documentation/admin-guide/mm/damon/usage.rst
@@ -363,15 +363,18 @@ number (``N``) to the file creates the number of child directories named ``0``
 to ``N-1``.  Each directory represents each filter.  The filters are evaluated
 in the numeric order.
 
-Each filter directory contains three files, namely ``type``, ``matcing``, and
-``memcg_path``.  You can write one of two special keywords, ``anon`` for
-anonymous pages, or ``memcg`` for specific memory cgroup filtering.  In case of
-the memory cgroup filtering, you can specify the memory cgroup of the interest
-by writing the path of the memory cgroup from the cgroups mount point to
-``memcg_path`` file.  You can write ``Y`` or ``N`` to ``matching`` file to
-filter out pages that does or does not match to the type, respectively.  Then,
-the scheme's action will not be applied to the pages that specified to be
-filtered out.
+Each filter directory contains five files, namely ``type``, ``matcing``,
+``memcg_path``, ``addr_start``, and ``addr_end``.  To ``type`` file, you can
+write one of three special keywords: ``anon`` for anonymous pages, ``memcg``
+for specific memory cgroup, or ``addr`` for specific address range (an
+open-ended interval) filtering.  In case of the memory cgroup filtering, you
+can specify the memory cgroup of the interest by writing the path of the memory
+cgroup from the cgroups mount point to ``memcg_path`` file.  In case of the
+address range filtering, you can specify the start and end address of the range
+to ``addr_start`` and ``addr_end`` files, respectively.  You can write ``Y`` or
+``N`` to ``matching`` file to filter out pages that does or does not match to
+the type, respectively.  Then, the scheme's action will not be applied to the
+pages that specified to be filtered out.
 
 For example, below restricts a DAMOS action to be applied to only non-anonymous
 pages of all memory cgroups except ``/having_care_already``.::
@@ -385,8 +388,14 @@ pages of all memory cgroups except ``/having_care_already``.::
     echo /having_care_already > 1/memcg_path
     echo N > 1/matching
 
-Note that filters are currently supported only when ``paddr``
-`implementation <sysfs_contexts>` is being used.
+Note that ``anon`` and ``memcg`` filters are currently supported only when
+``paddr`` `implementation <sysfs_contexts>` is being used.
+
+Also, memory regions that are filtered out by ``addr`` filters are not counted
+as the scheme has tried to those, while regions that filtered out by other type
+filters are counted as the scheme has tried to.  The difference is applied to
+:ref:`stats <damos_stats>` and :ref:`tried regions
+<sysfs_schemes_tried_regions>`.
 
 .. _sysfs_schemes_stats:
 
-- 
2.25.1

[RFC PATCH 08/13] mm/damon/core: implement target type damos filter

[SeongJae Park]

One DAMON context can have multiple monitoring targets, and DAMOS
schemes are applied to all targets.  In some cases, users need to apply
different scheme to different targets.  Retrieving monitoring results
via DAMON sysfs interface' 'tried_regions' directory could be one good
example.  Also, there could be cases that cgroup DAMOS filter is not
enough.  All such use cases can be worked around by having multiple
DAMON contexts having only single target, but it is inefficient in terms
of resource usage, thogh the overhead is not estimated to be huge.

Implement DAMON monitoring target based DAMOS filter for the case.  Like
address range target DAMOS filter, handle these filters in the DAMON
core layer, since it is more efficient than doing in operations set
layer.  This also means that regions that filtered out by monitoring
target type DAMOS filters are counted as not tried by the scheme.
Hence, target granularity monitoring results retrieval via DAMON sysfs
interface becomes available.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 include/linux/damon.h |  6 ++++++
 mm/damon/core.c       | 22 ++++++++++++++++------
 2 files changed, 22 insertions(+), 6 deletions(-)

diff --git a/include/linux/damon.h b/include/linux/damon.h
index 476f37a883a4..ae2664d1d5f1 100644
--- a/include/linux/damon.h
+++ b/include/linux/damon.h
@@ -227,6 +227,7 @@ struct damos_stat {
  * @DAMOS_FILTER_TYPE_ANON:	Anonymous pages.
  * @DAMOS_FILTER_TYPE_MEMCG:	Specific memcg's pages.
  * @DAMOS_FILTER_TYPE_ADDR:	Address range.
+ * @DAMOS_FILTER_TYPE_TARGET:	Data Access Monitoring target.
  * @NR_DAMOS_FILTER_TYPES:	Number of filter types.
  *
  * The anon pages type and memcg type filters are handled by underlying
@@ -244,6 +245,7 @@ enum damos_filter_type {
 	DAMOS_FILTER_TYPE_ANON,
 	DAMOS_FILTER_TYPE_MEMCG,
 	DAMOS_FILTER_TYPE_ADDR,
+	DAMOS_FILTER_TYPE_TARGET,
 	NR_DAMOS_FILTER_TYPES,
 };
 
@@ -253,6 +255,9 @@ enum damos_filter_type {
  * @matching:	If the matching page should filtered out or in.
  * @memcg_id:	Memcg id of the question if @type is DAMOS_FILTER_MEMCG.
  * @addr_range:	Address range if @type is DAMOS_FILTER_TYPE_ADDR.
+ * @target_idx:	Index of the &struct damon_target of
+ *		&damon_ctx->adaptive_targets if @type is
+ *		DAMOS_FILTER_TYPE_TARGET.
  * @list:	List head for siblings.
  *
  * Before applying the &damos->action to a memory region, DAMOS checks if each
@@ -266,6 +271,7 @@ struct damos_filter {
 	union {
 		unsigned short memcg_id;
 		struct damon_addr_range addr_range;
+		int target_idx;
 	};
 	struct list_head list;
 };
diff --git a/mm/damon/core.c b/mm/damon/core.c
index c061d289c832..334bc5823d83 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -906,13 +906,23 @@ static void damos_update_stat(struct damos *s,
 	s->stat.sz_applied += sz_applied;
 }
 
-static bool __damos_filter_out(struct damon_target *t, struct damon_region *r,
-		struct damos_filter *filter)
+static bool __damos_filter_out(struct damon_ctx *ctx, struct damon_target *t,
+		struct damon_region *r, struct damos_filter *filter)
 {
 	bool matched = false;
+	struct damon_target *ti;
+	int target_idx = 0;
 	unsigned long start, end;
 
 	switch (filter->type) {
+	case DAMOS_FILTER_TYPE_TARGET:
+		damon_for_each_target(ti, ctx) {
+			if (ti == t)
+				break;
+			target_idx++;
+		}
+		matched = target_idx == filter->target_idx;
+		break;
 	case DAMOS_FILTER_TYPE_ADDR:
 		start = ALIGN_DOWN(filter->addr_range.start, DAMON_MIN_REGION);
 		end = ALIGN_DOWN(filter->addr_range.end, DAMON_MIN_REGION);
@@ -944,13 +954,13 @@ static bool __damos_filter_out(struct damon_target *t, struct damon_region *r,
 	return matched == filter->matching;
 }
 
-static bool damos_filter_out(struct damon_target *t, struct damon_region *r,
-		struct damos *s)
+static bool damos_filter_out(struct damon_ctx *ctx, struct damon_target *t,
+		struct damon_region *r, struct damos *s)
 {
 	struct damos_filter *filter;
 
 	damos_for_each_filter(filter, s) {
-		if (__damos_filter_out(t, r, filter))
+		if (__damos_filter_out(ctx, t, r, filter))
 			return true;
 	}
 	return false;
@@ -982,7 +992,7 @@ static void damos_apply_scheme(struct damon_ctx *c, struct damon_target *t,
 			}
 			damon_split_region_at(t, r, sz);
 		}
-		if (damos_filter_out(t, r, s))
+		if (damos_filter_out(c, t, r, s))
 			return;
 		ktime_get_coarse_ts64(&begin);
 		if (c->callback.before_damos_apply)
-- 
2.25.1

[RFC PATCH 09/13] mm/damon/sysfs-schemes: support target damos filter

[SeongJae Park]

Extend DAMON sysfs interface to support the DAMON monitoring target
based DAMOS filter.  Users can use it via writing 'target' to the
filter's 'type' file and specifying the index of the target from the
corresponding DAMON context's monitoring targets list to 'target_idx'
sysfs file.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/sysfs-schemes.c | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/mm/damon/sysfs-schemes.c b/mm/damon/sysfs-schemes.c
index 03ddba3e216d..527e7d17eb3b 100644
--- a/mm/damon/sysfs-schemes.c
+++ b/mm/damon/sysfs-schemes.c
@@ -283,6 +283,7 @@ struct damon_sysfs_scheme_filter {
 	bool matching;
 	char *memcg_path;
 	struct damon_addr_range addr_range;
+	int target_idx;
 };
 
 static struct damon_sysfs_scheme_filter *damon_sysfs_scheme_filter_alloc(void)
@@ -295,6 +296,7 @@ static const char * const damon_sysfs_scheme_filter_type_strs[] = {
 	"anon",
 	"memcg",
 	"addr",
+	"target",
 };
 
 static ssize_t type_show(struct kobject *kobj,
@@ -413,6 +415,25 @@ static ssize_t addr_end_store(struct kobject *kobj,
 	return err ? err : count;
 }
 
+static ssize_t damon_target_idx_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	struct damon_sysfs_scheme_filter *filter = container_of(kobj,
+			struct damon_sysfs_scheme_filter, kobj);
+
+	return sysfs_emit(buf, "%d\n", filter->target_idx);
+}
+
+static ssize_t damon_target_idx_store(struct kobject *kobj,
+		struct kobj_attribute *attr, const char *buf, size_t count)
+{
+	struct damon_sysfs_scheme_filter *filter = container_of(kobj,
+			struct damon_sysfs_scheme_filter, kobj);
+	int err = kstrtoint(buf, 0, &filter->target_idx);
+
+	return err ? err : count;
+}
+
 static void damon_sysfs_scheme_filter_release(struct kobject *kobj)
 {
 	struct damon_sysfs_scheme_filter *filter = container_of(kobj,
@@ -437,12 +458,16 @@ static struct kobj_attribute damon_sysfs_scheme_filter_addr_start_attr =
 static struct kobj_attribute damon_sysfs_scheme_filter_addr_end_attr =
 		__ATTR_RW_MODE(addr_end, 0600);
 
+static struct kobj_attribute damon_sysfs_scheme_filter_damon_target_idx_attr =
+		__ATTR_RW_MODE(damon_target_idx, 0600);
+
 static struct attribute *damon_sysfs_scheme_filter_attrs[] = {
 	&damon_sysfs_scheme_filter_type_attr.attr,
 	&damon_sysfs_scheme_filter_matching_attr.attr,
 	&damon_sysfs_scheme_filter_memcg_path_attr.attr,
 	&damon_sysfs_scheme_filter_addr_start_attr.attr,
 	&damon_sysfs_scheme_filter_addr_end_attr.attr,
+	&damon_sysfs_scheme_filter_damon_target_idx_attr.attr,
 	NULL,
 };
 ATTRIBUTE_GROUPS(damon_sysfs_scheme_filter);
@@ -1539,6 +1564,8 @@ static int damon_sysfs_set_scheme_filters(struct damos *scheme,
 				return -EINVAL;
 			}
 			filter->addr_range = sysfs_filter->addr_range;
+		} else if (filter->type == DAMOS_FILTER_TYPE_TARGET) {
+			filter->target_idx = sysfs_filter->target_idx;
 		}
 
 		damos_add_filter(scheme, filter);
-- 
2.25.1

[RFC PATCH 10/13] selftests/damon/sysfs: test damon_target filter

[SeongJae Park]

Test existence of files and validity of input keyword for DAMON
monitoring target based DAMOS filter on DAMON sysfs interface.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 tools/testing/selftests/damon/sysfs.sh | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tools/testing/selftests/damon/sysfs.sh b/tools/testing/selftests/damon/sysfs.sh
index 5677cfd342fc..60a9a305aef0 100644
--- a/tools/testing/selftests/damon/sysfs.sh
+++ b/tools/testing/selftests/damon/sysfs.sh
@@ -104,11 +104,13 @@ test_filter()
 	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"
 	ensure_write_fail "$filter_dir/type" "foo" "invalid input"
 	ensure_file "$filter_dir/matching" "exist" "600"
 	ensure_file "$filter_dir/memcg_path" "exist" "600"
 	ensure_file "$filter_dir/addr_start" "exist" "600"
 	ensure_file "$filter_dir/addr_end" "exist" "600"
+	ensure_file "$filter_dir/damon_target_idx" "exist" "600"
 }
 
 test_filters()
-- 
2.25.1

[RFC PATCH 11/13] Docs/mm/damon/design: update for DAMON monitoring target type DAMOS filter

[SeongJae Park]

Update DAMON design document for the newly added DAMON monitoring target
type DAMOS filter.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 Documentation/mm/damon/design.rst | 33 +++++++++++++++++--------------
 1 file changed, 18 insertions(+), 15 deletions(-)

diff --git a/Documentation/mm/damon/design.rst b/Documentation/mm/damon/design.rst
index 134912166f5a..a20383d01a95 100644
--- a/Documentation/mm/damon/design.rst
+++ b/Documentation/mm/damon/design.rst
@@ -380,21 +380,24 @@ number of filters for each scheme.  Each filter specifies the type of target
 memory, and whether it should exclude the memory of the type (filter-out), or
 all except the memory of the type (filter-in).
 
-Currently, anonymous page, memory cgroup, and address range type filters are
-supported by the feature.  Some filter target types can require additional
-arguments.  For example, the memory cgroup filter type asks users to specify
-the file path of the memory cgroup for the filter, while the address range type
-asks the start and end addresses of the range.  Hence, users can apply specific
-schemes to only anonymous pages, non-anonymous pages, pages of specific
-cgroups, all pages excluding those of specific cgroups, pages in specific
-address range, and any combination of those.
-
-To handle filters efficiently, the address range type filter is handled by the
-core layer, while others are handled by operations set.  If a memory region is
-filtered by the core layer-handled filter, it is not counted as the scheme has
-tried to the region.  In contrast, if a memory regions is filtered by an
-operations set layer-handled filter, it is counted as the scheme has tried.
-The difference in accounting leads to changes in the statistics.
+Currently, anonymous page, memory cgroup, address range, and DAMON monitoring
+target type filters are supported by the feature.  Some filter target types
+require additional arguments.  The memory cgroup filter type asks users to
+specify the file path of the memory cgroup for the filter.  The address range
+type asks the start and end addresses of the range.  The DAMON monitoring
+target type asks the index of the target from the context's monitoring targets
+list.  Hence, users can apply specific schemes to only anonymous pages,
+non-anonymous pages, pages of specific cgroups, all pages excluding those of
+specific cgroups, pages in specific address range, pages in specific DAMON
+monitoring targets, and any combination of those.
+
+To handle filters efficiently, the address range and DAMON monitoring target
+type filters are handled by the core layer, while others are handled by
+operations set.  If a memory region is filtered by a core layer-handled filter,
+it is not counted as the scheme has tried to the region.  In contrast, if a
+memory regions is filtered by an operations set layer-handled filter, it is
+counted as the scheme has tried.  The difference in accounting leads to changes
+in the statistics.
 
 
 Application Programming Interface
-- 
2.25.1

[RFC PATCH 12/13] Docs/ABI/damon: update for DAMON monitoring target type DAMOS filter

[SeongJae Park]

Update DAMON ABI document for the newly added DAMON monitoring target
type DAMOS filter.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 Documentation/ABI/testing/sysfs-kernel-mm-damon | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/Documentation/ABI/testing/sysfs-kernel-mm-damon b/Documentation/ABI/testing/sysfs-kernel-mm-damon
index 0bc074d4618c..334352d198f8 100644
--- a/Documentation/ABI/testing/sysfs-kernel-mm-damon
+++ b/Documentation/ABI/testing/sysfs-kernel-mm-damon
@@ -272,8 +272,9 @@ Date:		Dec 2022
 Contact:	SeongJae Park <sj@kernel.org>
 Description:	Writing to and reading from this file sets and gets the type of
 		the memory of the interest.  'anon' for anonymous pages,
-		'memcg' for specific memory cgroup, or 'addr' for address range
-		(an open-ended interval) can be written and read.
+		'memcg' for specific memory cgroup, 'addr' for address range
+		(an open-ended interval), or 'target' for DAMON monitoring
+		target can be written and read.
 
 What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/filters/<F>/memcg_path
 Date:		Dec 2022
@@ -296,6 +297,12 @@ Description:	If 'addr' is written to the 'type' file, writing to or reading
 		from this file sets or gets the end address of the address
 		range for the filter.
 
+What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/filters/<F>/target_idx
+Date:		Dec 2022
+Contact:	SeongJae Park <sj@kernel.org>
+Description:	If 'target' is written to the 'type' file, writing to or
+		reading from this file sets or gets the index of the DAMON
+		monitoring target of the interest.
 
 What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/filters/<F>/matching
 Date:		Dec 2022
-- 
2.25.1

[RFC PATCH 13/13] Docs/admin-guide/mm/damon/usage: update for DAMON monitoring target type DAMOS filter

[SeongJae Park]

Update DAMON usage document for newly added DAMON monitoring target type
DAMOS filter.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 Documentation/admin-guide/mm/damon/usage.rst | 37 +++++++++++---------
 1 file changed, 20 insertions(+), 17 deletions(-)

diff --git a/Documentation/admin-guide/mm/damon/usage.rst b/Documentation/admin-guide/mm/damon/usage.rst
index a9cb9949b796..084f0a32b421 100644
--- a/Documentation/admin-guide/mm/damon/usage.rst
+++ b/Documentation/admin-guide/mm/damon/usage.rst
@@ -363,18 +363,21 @@ number (``N``) to the file creates the number of child directories named ``0``
 to ``N-1``.  Each directory represents each filter.  The filters are evaluated
 in the numeric order.
 
-Each filter directory contains five files, namely ``type``, ``matcing``,
-``memcg_path``, ``addr_start``, and ``addr_end``.  To ``type`` file, you can
-write one of three special keywords: ``anon`` for anonymous pages, ``memcg``
-for specific memory cgroup, or ``addr`` for specific address range (an
-open-ended interval) filtering.  In case of the memory cgroup filtering, you
-can specify the memory cgroup of the interest by writing the path of the memory
-cgroup from the cgroups mount point to ``memcg_path`` file.  In case of the
-address range filtering, you can specify the start and end address of the range
-to ``addr_start`` and ``addr_end`` files, respectively.  You can write ``Y`` or
-``N`` to ``matching`` file to filter out pages that does or does not match to
-the type, respectively.  Then, the scheme's action will not be applied to the
-pages that specified to be filtered out.
+Each filter directory contains six files, namely ``type``, ``matcing``,
+``memcg_path``, ``addr_start``, ``addr_end``, and ``target_idx``.  To ``type``
+file, you can write one of four special keywords: ``anon`` for anonymous pages,
+``memcg`` for specific memory cgroup, ``addr`` for specific address range (an
+open-ended interval), or ``target`` for specific DAMON monitoring target
+filtering.  In case of the memory cgroup filtering, you can specify the memory
+cgroup of the interest by writing the path of the memory cgroup from the
+cgroups mount point to ``memcg_path`` file.  In case of the address range
+filtering, you can specify the start and end address of the range to
+``addr_start`` and ``addr_end`` files, respectively.  For the DAMON monitoring
+target filtering, you can specify the index of the target between the list of
+the DAMON context's monitoring targets list to ``target_idx`` file.  You can
+write ``Y`` or ``N`` to ``matching`` file to filter out pages that does or does
+not match to the type, respectively.  Then, the scheme's action will not be
+applied to the pages that specified to be filtered out.
 
 For example, below restricts a DAMOS action to be applied to only non-anonymous
 pages of all memory cgroups except ``/having_care_already``.::
@@ -391,11 +394,11 @@ pages of all memory cgroups except ``/having_care_already``.::
 Note that ``anon`` and ``memcg`` filters are currently supported only when
 ``paddr`` `implementation <sysfs_contexts>` is being used.
 
-Also, memory regions that are filtered out by ``addr`` filters are not counted
-as the scheme has tried to those, while regions that filtered out by other type
-filters are counted as the scheme has tried to.  The difference is applied to
-:ref:`stats <damos_stats>` and :ref:`tried regions
-<sysfs_schemes_tried_regions>`.
+Also, memory regions that are filtered out by ``addr`` or ``target`` filters
+are not counted as the scheme has tried to those, while regions that filtered
+out by other type filters are counted as the scheme has tried to.  The
+difference is applied to :ref:`stats <damos_stats>` and
+:ref:`tried regions <sysfs_schemes_tried_regions>`.
 
 .. _sysfs_schemes_stats:
 
-- 
2.25.1