linux-kernel - [PATCH 4/8] memcg: use cgroup_id() instead of cgroup

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Message-ID: <20251225232116.294540-5-shakeel.butt@linux.dev>
Date: Thu, 25 Dec 2025 15:21:12 -0800
From: Shakeel Butt <shakeel.butt@...ux.dev>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: Johannes Weiner <hannes@...xchg.org>,
	Michal Hocko <mhocko@...nel.org>,
	Roman Gushchin <roman.gushchin@...ux.dev>,
	Muchun Song <muchun.song@...ux.dev>,
	SeongJae Park <sj@...nel.org>,
	Meta kernel team <kernel-team@...a.com>,
	linux-mm@...ck.org,
	cgroups@...r.kernel.org,
	damon@...ts.linux.dev,
	linux-kernel@...r.kernel.org
Subject: [PATCH 4/8] memcg: use cgroup_id() instead of cgroup_ino() for memcg ID

Switch mem_cgroup_ino() from using cgroup_ino() to cgroup_id(). The
cgroup_ino() returns the kernfs inode number while cgroup_id() returns
the kernfs node ID. For 64-bit systems, they are the same. Also
cgroup_get_from_id() expects 64-bit node ID which is called by
mem_cgroup_get_from_ino().

Change the type from unsigned long to u64 to match cgroup_id()'s return
type, and update the format specifiers accordingly.

Note that the names mem_cgroup_ino() and mem_cgroup_get_from_ino() are
now misnomers since they deal with cgroup IDs rather than inode numbers.
A follow-up patch will rename them.

Signed-off-by: Shakeel Butt <shakeel.butt@...ux.dev>
---
 include/linux/memcontrol.h | 10 +++++-----
 mm/memcontrol.c            |  2 +-
 mm/shrinker_debug.c        |  7 ++++---
 3 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 77f32be26ea8..c823150ec288 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -836,12 +836,12 @@ static inline unsigned short mem_cgroup_id(struct mem_cgroup *memcg)
 }
 struct mem_cgroup *mem_cgroup_from_id(unsigned short id);
 
-static inline unsigned long mem_cgroup_ino(struct mem_cgroup *memcg)
+static inline u64 mem_cgroup_ino(struct mem_cgroup *memcg)
 {
-	return memcg ? cgroup_ino(memcg->css.cgroup) : 0;
+	return memcg ? cgroup_id(memcg->css.cgroup) : 0;
 }
 
-struct mem_cgroup *mem_cgroup_get_from_ino(unsigned long ino);
+struct mem_cgroup *mem_cgroup_get_from_ino(u64 ino);
 
 static inline struct mem_cgroup *mem_cgroup_from_seq(struct seq_file *m)
 {
@@ -1306,12 +1306,12 @@ static inline struct mem_cgroup *mem_cgroup_from_private_id(unsigned short id)
 	return NULL;
 }
 
-static inline unsigned long mem_cgroup_ino(struct mem_cgroup *memcg)
+static inline u64 mem_cgroup_ino(struct mem_cgroup *memcg)
 {
 	return 0;
 }
 
-static inline struct mem_cgroup *mem_cgroup_get_from_ino(unsigned long ino)
+static inline struct mem_cgroup *mem_cgroup_get_from_ino(u64 ino)
 {
 	return NULL;
 }
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 92beb74482fa..1ff2f9bd820c 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3620,7 +3620,7 @@ struct mem_cgroup *mem_cgroup_from_id(unsigned short id)
 	return mem_cgroup_from_private_id(id);
 }
 
-struct mem_cgroup *mem_cgroup_get_from_ino(unsigned long ino)
+struct mem_cgroup *mem_cgroup_get_from_ino(u64 ino)
 {
 	struct cgroup *cgrp;
 	struct cgroup_subsys_state *css;
diff --git a/mm/shrinker_debug.c b/mm/shrinker_debug.c
index 8aaeb8f5c3af..7ef16a0b2959 100644
--- a/mm/shrinker_debug.c
+++ b/mm/shrinker_debug.c
@@ -70,7 +70,7 @@ static int shrinker_debugfs_count_show(struct seq_file *m, void *v)
 					       memcg_aware ? memcg : NULL,
 					       count_per_node);
 		if (total) {
-			seq_printf(m, "%lu", mem_cgroup_ino(memcg));
+			seq_printf(m, "%llu", mem_cgroup_ino(memcg));
 			for_each_node(nid)
 				seq_printf(m, " %lu", count_per_node[nid]);
 			seq_putc(m, '\n');
@@ -106,7 +106,8 @@ static ssize_t shrinker_debugfs_scan_write(struct file *file,
 					   size_t size, loff_t *pos)
 {
 	struct shrinker *shrinker = file->private_data;
-	unsigned long nr_to_scan = 0, ino, read_len;
+	unsigned long nr_to_scan = 0, read_len;
+	u64 ino;
 	struct shrink_control sc = {
 		.gfp_mask = GFP_KERNEL,
 	};
@@ -119,7 +120,7 @@ static ssize_t shrinker_debugfs_scan_write(struct file *file,
 		return -EFAULT;
 	kbuf[read_len] = '\0';
 
-	if (sscanf(kbuf, "%lu %d %lu", &ino, &nid, &nr_to_scan) != 3)
+	if (sscanf(kbuf, "%llu %d %lu", &ino, &nid, &nr_to_scan) != 3)
 		return -EINVAL;
 
 	if (nid < 0 || nid >= nr_node_ids)
-- 
2.47.3