[PATCH 1/3] mm/damon/core: add DAMOS_QUOTA_NODE_TARGET_MEM_BP metric

[Ravi Jonnalagadda <ravis.opensrc@gmail.com>]

Add a new quota goal metric DAMOS_QUOTA_NODE_TARGET_MEM_BP for
physical address space-based DAMON operation schemes. This metric
represents the ratio of scheme-eligible memory on a specific NUMA node
to that node's total capacity, expressed in basis points (1/10000).

The metric enables auto-tuning of DAMOS quotas based on how much
memory on a node matches the scheme's access pattern criteria, which
is essential for controlling memory migration in heterogeneous memory
systems (e.g., DRAM and CXL memory tiering).

Suggested-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Ravi Jonnalagadda <ravis.opensrc@gmail.com>
---
 include/linux/damon.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/include/linux/damon.h b/include/linux/damon.h
index 3813373a9200..5eebb8aaab85 100644
--- a/include/linux/damon.h
+++ b/include/linux/damon.h
@@ -155,6 +155,7 @@ enum damos_action {
  * @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.
  * @DAMOS_QUOTA_NODE_MEMCG_FREE_BP:	MemFree ratio of a node for a cgroup.
+ * @DAMOS_QUOTA_NODE_TARGET_MEM_BP:	Scheme-eligible memory ratio of a node.
  * @NR_DAMOS_QUOTA_GOAL_METRICS:	Number of DAMOS quota goal metrics.
  *
  * Metrics equal to larger than @NR_DAMOS_QUOTA_GOAL_METRICS are unsupported.
@@ -166,6 +167,7 @@ enum damos_quota_goal_metric {
 	DAMOS_QUOTA_NODE_MEM_FREE_BP,
 	DAMOS_QUOTA_NODE_MEMCG_USED_BP,
 	DAMOS_QUOTA_NODE_MEMCG_FREE_BP,
+	DAMOS_QUOTA_NODE_TARGET_MEM_BP,
 	NR_DAMOS_QUOTA_GOAL_METRICS,
 };
 
@@ -193,6 +195,9 @@ enum damos_quota_goal_metric {
  *
  * If @metric is DAMOS_QUOTA_NODE_MEMCG_{USED,FREE}_BP, @nid and @memcg_id
  * represents the node id and the cgroup to account the used memory for.
+ *
+ * If @metric is DAMOS_QUOTA_NODE_TARGET_MEM_BP, @nid represents the node
+ * to measure scheme-eligible memory ratio against its capacity.
  */
 struct damos_quota_goal {
 	enum damos_quota_goal_metric metric;
-- 
2.43.0