From de6be06f4a2dc88066e6227ec6864e7903985549 Mon Sep 17 00:00:00 2001
From: Tal Zussman <tz2294@columbia.edu>
Date: Tue, 15 Sep 2026 19:20:15 -0400
Subject: [PATCH] mm: memcontrol: constify the zswap and socket pressure
 helpers

mem_cgroup_zswap_writeback_enabled() only reads the zswap_writeback flags,
and mem_cgroup_get_socket_pressure() only reads the socket pressure
timestamp.  Constify them.

Link: https://lore.kernel.org/20260915-folio_memcg-const-v3-11-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 | 8 ++++----
 mm/memcontrol.c            | 2 +-
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index f11899085473..64c183be8cbf 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -1684,7 +1684,7 @@ static inline void mem_cgroup_set_socket_pressure(struct mem_cgroup *memcg)
 	write_sequnlock_irqrestore(&memcg->socket_pressure_seqlock, flags);
 }
 
-static inline u64 mem_cgroup_get_socket_pressure(struct mem_cgroup *memcg)
+static inline u64 mem_cgroup_get_socket_pressure(const struct mem_cgroup *memcg)
 {
 	unsigned int seq;
 	u64 val;
@@ -1702,7 +1702,7 @@ static inline void mem_cgroup_set_socket_pressure(struct mem_cgroup *memcg)
 	WRITE_ONCE(memcg->socket_pressure, jiffies + HZ);
 }
 
-static inline u64 mem_cgroup_get_socket_pressure(struct mem_cgroup *memcg)
+static inline u64 mem_cgroup_get_socket_pressure(const struct mem_cgroup *memcg)
 {
 	return READ_ONCE(memcg->socket_pressure);
 }
@@ -1937,7 +1937,7 @@ static inline void mem_cgroup_calculate_protection_path(struct mem_cgroup *root,
 bool obj_cgroup_may_zswap(struct obj_cgroup *objcg);
 void obj_cgroup_charge_zswap(struct obj_cgroup *objcg, size_t size);
 void obj_cgroup_uncharge_zswap(struct obj_cgroup *objcg, size_t size);
-bool mem_cgroup_zswap_writeback_enabled(struct mem_cgroup *memcg);
+bool mem_cgroup_zswap_writeback_enabled(const struct mem_cgroup *memcg);
 #else
 static inline bool obj_cgroup_may_zswap(struct obj_cgroup *objcg)
 {
@@ -1951,7 +1951,7 @@ static inline void obj_cgroup_uncharge_zswap(struct obj_cgroup *objcg,
 					     size_t size)
 {
 }
-static inline bool mem_cgroup_zswap_writeback_enabled(struct mem_cgroup *memcg)
+static inline bool mem_cgroup_zswap_writeback_enabled(const struct mem_cgroup *memcg)
 {
 	/* if zswap is disabled, do not block pages going to the swapping device */
 	return true;
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 36101129679f..4d00748c8a5b 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -6318,7 +6318,7 @@ void obj_cgroup_uncharge_zswap(struct obj_cgroup *objcg, size_t size)
 	rcu_read_unlock();
 }
 
-bool mem_cgroup_zswap_writeback_enabled(struct mem_cgroup *memcg)
+bool mem_cgroup_zswap_writeback_enabled(const struct mem_cgroup *memcg)
 {
 	/* if zswap is disabled, do not block pages going to the swapping device */
 	if (!zswap_is_enabled())