From bc936f771a2d18bf2fa5090a5050f8d35b420abd Mon Sep 17 00:00:00 2001
From: Tal Zussman <tz2294@columbia.edu>
Date: Tue, 15 Sep 2026 19:20:14 -0400
Subject: [PATCH] mm: memcontrol: constify mem_cgroup_swappiness() and
 mem_cgroup_get_max()

Both only read swappiness and the memory limits. Constify them.

Link: https://lore.kernel.org/20260915-folio_memcg-const-v3-10-c239a6010b58@columbia.edu
Signed-off-by: Tal Zussman <tz2294@columbia.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Muchun Song <muchun.song@linux.dev>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Acked-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <baoquan.he@linux.dev>
Cc: Barry Song <baohua@kernel.org>
Cc: Chris Li <chrisl@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Wei Xu <weixugc@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
---
 include/linux/memcontrol.h | 4 ++--
 mm/memcontrol.c            | 2 +-
 mm/swap.h                  | 2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 9beb065c0879..f11899085473 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -941,7 +941,7 @@ static inline void mem_cgroup_handle_over_high(gfp_t gfp_mask)
 		__mem_cgroup_handle_over_high(gfp_mask);
 }
 
-unsigned long mem_cgroup_get_max(struct mem_cgroup *memcg);
+unsigned long mem_cgroup_get_max(const struct mem_cgroup *memcg);
 
 void mem_cgroup_print_oom_context(const struct mem_cgroup *memcg,
 				struct task_struct *p);
@@ -1372,7 +1372,7 @@ unsigned long mem_cgroup_get_zone_lru_size(const struct lruvec *lruvec,
 	return 0;
 }
 
-static inline unsigned long mem_cgroup_get_max(struct mem_cgroup *memcg)
+static inline unsigned long mem_cgroup_get_max(const struct mem_cgroup *memcg)
 {
 	return 0;
 }
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index d954ffb43a43..36101129679f 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1898,7 +1898,7 @@ void mem_cgroup_print_oom_meminfo(struct mem_cgroup *memcg)
 /*
  * Return the memory (and swap, if configured) limit for a memcg.
  */
-unsigned long mem_cgroup_get_max(struct mem_cgroup *memcg)
+unsigned long mem_cgroup_get_max(const struct mem_cgroup *memcg)
 {
 	unsigned long max = READ_ONCE(memcg->memory.max);
 
diff --git a/mm/swap.h b/mm/swap.h
index b3b54c28929a..1957960dc60d 100644
--- a/mm/swap.h
+++ b/mm/swap.h
@@ -82,7 +82,7 @@ enum swap_cluster_flags {
 
 extern int vm_swappiness;
 
-static inline int mem_cgroup_swappiness(struct mem_cgroup *memcg)
+static inline int mem_cgroup_swappiness(const struct mem_cgroup *memcg)
 {
 #ifdef CONFIG_MEMCG_V1
 	if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) &&