[RFC PATCH v3 22/28] mm/damon/core: introduce DAMON_FILTER_TYPE_MEMCG

[SeongJae Park <sj@kernel.org>]

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       | 14 ++++++++++++++
 2 files changed, 20 insertions(+)

diff --git a/include/linux/damon.h b/include/linux/damon.h
index d3b6296700a08..56a76781fde22 100644
--- a/include/linux/damon.h
+++ b/include/linux/damon.h
@@ -733,9 +733,11 @@ 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,
 };
 
 /**
@@ -744,12 +746,16 @@ enum damon_filter_type {
  * @type:	Type of the region.
  * @matching:	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 11b513eb077fe..332d13d9f8603 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -1422,6 +1422,13 @@ 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,
@@ -1446,6 +1453,13 @@ static int damon_commit_filters(struct damon_probe *dst,
 				src_filter->matching, src_filter->allow);
 		if (!new_filter)
 			return -ENOMEM;
+		switch (src_filter->type) {
+		case DAMON_FILTER_TYPE_MEMCG:
+			new_filter->memcg_id = src_filter->memcg_id;
+			break;
+		default:
+			break;
+		}
 		damon_add_filter(dst, new_filter);
 	}
 	return 0;
-- 
2.47.3