From 558605a530e079a59bafe4877b06100055f7d91d Mon Sep 17 00:00:00 2001
From: Chen Ridong <chenridong@huawei.com>
Date: Thu, 11 Dec 2025 01:30:18 +0000
Subject: [PATCH] memcg: move mem_cgroup_usage memcontrol-v1.c
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Patch series "memcg cleanups", v3.

Two code moves/removals with no behavior change.


This patch (of 2):

Currently, mem_cgroup_usage is only used for v1, just move it to
memcontrol-v1.c

Link: https://lkml.kernel.org/r/20251211013019.2080004-1-chenridong@huaweicloud.com
Link: https://lkml.kernel.org/r/20251211013019.2080004-2-chenridong@huaweicloud.com
Signed-off-by: Chen Ridong <chenridong@huawei.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Acked-by: Michal Koutný <mkoutny@suse.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Lu Jialin <lujialin4@huawei.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Wei Xu <weixugc@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 mm/memcontrol-v1.c | 22 ++++++++++++++++++++++
 mm/memcontrol-v1.h |  2 --
 mm/memcontrol.c    | 22 ----------------------
 3 files changed, 22 insertions(+), 24 deletions(-)

diff --git a/mm/memcontrol-v1.c b/mm/memcontrol-v1.c
index 6eed14bff7426..0b50cb122ff3d 100644
--- a/mm/memcontrol-v1.c
+++ b/mm/memcontrol-v1.c
@@ -427,6 +427,28 @@ static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css,
 }
 #endif
 
+static unsigned long mem_cgroup_usage(struct mem_cgroup *memcg, bool swap)
+{
+	unsigned long val;
+
+	if (mem_cgroup_is_root(memcg)) {
+		/*
+		 * Approximate root's usage from global state. This isn't
+		 * perfect, but the root usage was always an approximation.
+		 */
+		val = global_node_page_state(NR_FILE_PAGES) +
+			global_node_page_state(NR_ANON_MAPPED);
+		if (swap)
+			val += total_swap_pages - get_nr_swap_pages();
+	} else {
+		if (!swap)
+			val = page_counter_read(&memcg->memory);
+		else
+			val = page_counter_read(&memcg->memsw);
+	}
+	return val;
+}
+
 static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap)
 {
 	struct mem_cgroup_threshold_ary *t;
diff --git a/mm/memcontrol-v1.h b/mm/memcontrol-v1.h
index 6358464bb4160..e92b21af92b1b 100644
--- a/mm/memcontrol-v1.h
+++ b/mm/memcontrol-v1.h
@@ -22,8 +22,6 @@
 	     iter != NULL;				\
 	     iter = mem_cgroup_iter(NULL, iter, NULL))
 
-unsigned long mem_cgroup_usage(struct mem_cgroup *memcg, bool swap);
-
 void drain_all_stock(struct mem_cgroup *root_memcg);
 
 unsigned long memcg_events(struct mem_cgroup *memcg, int event);
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 86f43b7e5f710..7d4b93d30eb0d 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3272,28 +3272,6 @@ void folio_split_memcg_refs(struct folio *folio, unsigned old_order,
 	css_get_many(&__folio_memcg(folio)->css, new_refs);
 }
 
-unsigned long mem_cgroup_usage(struct mem_cgroup *memcg, bool swap)
-{
-	unsigned long val;
-
-	if (mem_cgroup_is_root(memcg)) {
-		/*
-		 * Approximate root's usage from global state. This isn't
-		 * perfect, but the root usage was always an approximation.
-		 */
-		val = global_node_page_state(NR_FILE_PAGES) +
-			global_node_page_state(NR_ANON_MAPPED);
-		if (swap)
-			val += total_swap_pages - get_nr_swap_pages();
-	} else {
-		if (!swap)
-			val = page_counter_read(&memcg->memory);
-		else
-			val = page_counter_read(&memcg->memsw);
-	}
-	return val;
-}
-
 static int memcg_online_kmem(struct mem_cgroup *memcg)
 {
 	struct obj_cgroup *objcg;
-- 
2.47.3