[PATCH 1/2] mm/damon: implement a new DAMOS filter type for active pages

[Nhat Pham]

Implement a DAMOS filter type for active pages on DAMON kernel API,
and add support of it from the physical address space DAMON operations
set (paddr).

Suggested-by: SeongJae Park <sj@xxxxxxxxxx>
Signed-off-by: Nhat Pham <nphamcs@xxxxxxxxx>
---
 include/linux/damon.h    | 2 ++
 mm/damon/paddr.c         | 3 +++
 mm/damon/sysfs-schemes.c | 1 +
 3 files changed, 6 insertions(+)

diff --git a/include/linux/damon.h b/include/linux/damon.h
index 3db4f77261f5..47e36e6ea203 100644
--- a/include/linux/damon.h
+++ b/include/linux/damon.h
@@ -334,6 +334,7 @@ struct damos_stat {
 /**
  * enum damos_filter_type - Type of memory for &struct damos_filter
  * @DAMOS_FILTER_TYPE_ANON:	Anonymous pages.
+ * @DAMOS_FILTER_TYPE_ACTIVE:	Active pages.
  * @DAMOS_FILTER_TYPE_MEMCG:	Specific memcg's pages.
  * @DAMOS_FILTER_TYPE_YOUNG:	Recently accessed pages.
  * @DAMOS_FILTER_TYPE_HUGEPAGE_SIZE:	Page is part of a hugepage.
@@ -355,6 +356,7 @@ struct damos_stat {
  */
 enum damos_filter_type {
 	DAMOS_FILTER_TYPE_ANON,
+	DAMOS_FILTER_TYPE_ACTIVE,
 	DAMOS_FILTER_TYPE_MEMCG,
 	DAMOS_FILTER_TYPE_YOUNG,
 	DAMOS_FILTER_TYPE_HUGEPAGE_SIZE,
diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c
index b08847ef9b81..1b70d3f36046 100644
--- a/mm/damon/paddr.c
+++ b/mm/damon/paddr.c
@@ -217,6 +217,9 @@ static bool damos_pa_filter_match(struct damos_filter *filter,
 	case DAMOS_FILTER_TYPE_ANON:
 		matched = folio_test_anon(folio);
 		break;
+	case DAMOS_FILTER_TYPE_ACTIVE:
+		matched = folio_test_active(folio);
+		break;
 	case DAMOS_FILTER_TYPE_MEMCG:
 		rcu_read_lock();
 		memcg = folio_memcg_check(folio);
diff --git a/mm/damon/sysfs-schemes.c b/mm/damon/sysfs-schemes.c
index 5023f2b690d6..23b562df0839 100644
--- a/mm/damon/sysfs-schemes.c
+++ b/mm/damon/sysfs-schemes.c
@@ -344,6 +344,7 @@ static struct damon_sysfs_scheme_filter *damon_sysfs_scheme_filter_alloc(
 /* Should match with enum damos_filter_type */
 static const char * const damon_sysfs_scheme_filter_type_strs[] = {
 	"anon",
+	"active",
 	"memcg",
 	"young",
 	"hugepage_size",
-- 
2.47.1