Define a new DAMOS quota auto-tuning target metric for per-cgroup
per-node memory usage.  For specifying the cgroup of the interest, add a
field, namely memcg_id, to damos_quota_goal struct.

Note that this commit is only implementing the interface.  The handling
of the interface (the metric value calculation) will be implemented in
the following commit.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 include/linux/damon.h | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/include/linux/damon.h b/include/linux/damon.h
index dc9c310e0e75..0d63ceb7e6ef 100644
--- a/include/linux/damon.h
+++ b/include/linux/damon.h
@@ -147,6 +147,7 @@ enum damos_action {
  * @DAMOS_QUOTA_SOME_MEM_PSI_US:	System level some memory PSI in us.
  * @DAMOS_QUOTA_NODE_MEM_USED_BP:	MemUsed ratio of a node.
  * @DAMOS_QUOTA_NODE_MEM_FREE_BP:	MemFree ratio of a node.
+ * @DAMOS_QUOTA_NODE_MEMCG_USED_BP:	MemUsed ratio of a node for a cgroup.
  * @NR_DAMOS_QUOTA_GOAL_METRICS:	Number of DAMOS quota goal metrics.
  *
  * Metrics equal to larger than @NR_DAMOS_QUOTA_GOAL_METRICS are unsupported.
@@ -156,6 +157,7 @@ enum damos_quota_goal_metric {
 	DAMOS_QUOTA_SOME_MEM_PSI_US,
 	DAMOS_QUOTA_NODE_MEM_USED_BP,
 	DAMOS_QUOTA_NODE_MEM_FREE_BP,
+	DAMOS_QUOTA_NODE_MEMCG_USED_BP,
 	NR_DAMOS_QUOTA_GOAL_METRICS,
 };
 
@@ -166,6 +168,7 @@ enum damos_quota_goal_metric {
  * @current_value:	Current value of @metric.
  * @last_psi_total:	Last measured total PSI
  * @nid:		Node id.
+ * @memcg_id:		Memcg id.
  * @list:		List head for siblings.
  *
  * Data structure for getting the current score of the quota tuning goal.  The
@@ -179,6 +182,9 @@ enum damos_quota_goal_metric {
  *
  * If @metric is DAMOS_QUOTA_NODE_MEM_{USED,FREE}_BP, @nid represents the node
  * id of the target node to account the used/free memory.
+ *
+ * If @metric is DAMOS_QUOTA_NODE_MEMCG_USED_BP, @nid and @memcg_id represents
+ * the node id and the cgroup to account the used memory for.
  */
 struct damos_quota_goal {
 	enum damos_quota_goal_metric metric;
@@ -187,7 +193,10 @@ struct damos_quota_goal {
 	/* metric-dependent fields */
 	union {
 		u64 last_psi_total;
-		int nid;
+		struct {
+			int nid;
+			unsigned short memcg_id;
+		};
 	};
 	struct list_head list;
 };
-- 
2.39.5