[PATCH 5/8] mm/damon: use cgroup ID instead of private memcg ID

[Shakeel Butt <shakeel.butt@linux.dev>]

DAMON was using the internal private memcg ID which is meant for
tracking kernel objects that outlive their cgroup. Switch to using the
public cgroup ID instead.

Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
---
 include/linux/damon.h    | 4 ++--
 mm/damon/core.c          | 7 ++-----
 mm/damon/ops-common.c    | 2 +-
 mm/damon/sysfs-schemes.c | 8 ++++----
 4 files changed, 9 insertions(+), 12 deletions(-)

diff --git a/include/linux/damon.h b/include/linux/damon.h
index a67292a2f09d..650e7ecfa32b 100644
--- a/include/linux/damon.h
+++ b/include/linux/damon.h
@@ -203,7 +203,7 @@ struct damos_quota_goal {
 		u64 last_psi_total;
 		struct {
 			int nid;
-			unsigned short memcg_id;
+			u64 memcg_id;
 		};
 	};
 	struct list_head list;
@@ -419,7 +419,7 @@ struct damos_filter {
 	bool matching;
 	bool allow;
 	union {
-		unsigned short memcg_id;
+		u64 memcg_id;
 		struct damon_addr_range addr_range;
 		int target_idx;
 		struct damon_size_range sz_range;
diff --git a/mm/damon/core.c b/mm/damon/core.c
index 2d3e8006db50..23c44811ff7f 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -2065,16 +2065,13 @@ static unsigned long damos_get_node_memcg_used_bp(
 	unsigned long used_pages, numerator;
 	struct sysinfo i;
 
-	rcu_read_lock();
-	memcg = mem_cgroup_from_id(goal->memcg_id);
-	if (!memcg || !mem_cgroup_tryget(memcg)) {
-		rcu_read_unlock();
+	memcg = mem_cgroup_get_from_ino(goal->memcg_id);
+	if (!memcg) {
 		if (goal->metric == DAMOS_QUOTA_NODE_MEMCG_USED_BP)
 			return 0;
 		else	/* DAMOS_QUOTA_NODE_MEMCG_FREE_BP */
 			return 10000;
 	}
-	rcu_read_unlock();
 
 	mem_cgroup_flush_stats(memcg);
 	lruvec = mem_cgroup_lruvec(memcg, NODE_DATA(goal->nid));
diff --git a/mm/damon/ops-common.c b/mm/damon/ops-common.c
index a218d9922234..dd81db95f901 100644
--- a/mm/damon/ops-common.c
+++ b/mm/damon/ops-common.c
@@ -274,7 +274,7 @@ bool damos_folio_filter_match(struct damos_filter *filter, struct folio *folio)
 		if (!memcg)
 			matched = false;
 		else
-			matched = filter->memcg_id == mem_cgroup_id(memcg);
+			matched = filter->memcg_id == mem_cgroup_ino(memcg);
 		rcu_read_unlock();
 		break;
 	case DAMOS_FILTER_TYPE_YOUNG:
diff --git a/mm/damon/sysfs-schemes.c b/mm/damon/sysfs-schemes.c
index e198234f0763..79aa917ab3c0 100644
--- a/mm/damon/sysfs-schemes.c
+++ b/mm/damon/sysfs-schemes.c
@@ -2492,7 +2492,7 @@ static bool damon_sysfs_memcg_path_eq(struct mem_cgroup *memcg,
 	return false;
 }
 
-static int damon_sysfs_memcg_path_to_id(char *memcg_path, unsigned short *id)
+static int damon_sysfs_memcg_path_to_id(char *memcg_path, u64 *id)
 {
 	struct mem_cgroup *memcg;
 	char *path;
@@ -2507,11 +2507,11 @@ static int damon_sysfs_memcg_path_to_id(char *memcg_path, unsigned short *id)
 
 	for (memcg = mem_cgroup_iter(NULL, NULL, NULL); memcg;
 			memcg = mem_cgroup_iter(NULL, memcg, NULL)) {
-		/* skip removed memcg */
-		if (!mem_cgroup_id(memcg))
+		/* skip offlined memcg */
+		if (!mem_cgroup_online(memcg))
 			continue;
 		if (damon_sysfs_memcg_path_eq(memcg, path, memcg_path)) {
-			*id = mem_cgroup_id(memcg);
+			*id = mem_cgroup_ino(memcg);
 			found = true;
 			break;
 		}
-- 
2.47.3