Belonging memory cgoup is another data attribute that can be useful to
monitor.  Introduce a new DAMON filter type, namely
DAMON_FILTER_TYPE_MEMCG, for monitoring of this attribute.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 include/linux/damon.h | 6 ++++++
 mm/damon/core.c       | 7 +++++++
 2 files changed, 13 insertions(+)

diff --git a/include/linux/damon.h b/include/linux/damon.h
index e9ca40cdd9102..3dec0947b93f0 100644
--- a/include/linux/damon.h
+++ b/include/linux/damon.h
@@ -740,9 +740,11 @@ struct damon_intervals_goal {
  * enum damon_filter_type - Type of &struct damon_filter
  *
  * @DAMON_FILTER_TYPE_ANON:	Anonymous pages.
+ * @DAMON_FILTER_TYPE_MEMCG:	Specific memcg's pages.
  */
 enum damon_filter_type {
 	DAMON_FILTER_TYPE_ANON,
+	DAMON_FILTER_TYPE_MEMCG,
 };
 
 /**
@@ -751,12 +753,16 @@ enum damon_filter_type {
  * @type:	Type of the region.
  * @matcing:	Whether this filter is for the type-matching ones.
  * @allow:	Whether the @type-@matching ones should pass this filter.
+ * @memcg_id:	Memcg id of the question if @type is DAMON_FILTER_MEMCG.
  * @list:	Siblings list.
  */
 struct damon_filter {
 	enum damon_filter_type type;
 	bool matching;
 	bool allow;
+	union {
+		u64 memcg_id;
+	};
 	struct list_head list;
 };
 
diff --git a/mm/damon/core.c b/mm/damon/core.c
index 14b15c9876516..ef751898a3c06 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -1430,6 +1430,13 @@ static void damon_commit_filter(struct damon_filter *dst,
 	dst->type = src->type;
 	dst->matching = src->matching;
 	dst->allow = src->allow;
+	switch (dst->type) {
+	case DAMON_FILTER_TYPE_MEMCG:
+		dst->memcg_id = src->memcg_id;
+		break;
+	default:
+		break;
+	}
 }
 
 static int damon_commit_filters(struct damon_probe *dst,
-- 
2.47.3