[PATCH 0/2] memcg: remove unused page-based helpers

[PATCH 0/2] memcg: remove unused page-based helpers

[Sang-Heon Jeon]

Hello,

While reading memcontrol.h, I found two page-based helpers that have
no callers.

No functional change.

Sang-Heon Jeon (2):
  memcg: remove unused page_memcg_check()
  memcg: remove unused mod_memcg_page_state()

 include/linux/memcontrol.h | 32 --------------------------------
 1 file changed, 32 deletions(-)

-- 
2.43.0

[PATCH 1/2] memcg: remove unused page_memcg_check()

[Sang-Heon Jeon]

Since commit 90f095b816e2 ("mm/page_owner: use memcg_data snapshot to
avoid TOCTOU in print_page_owner_memcg()"), page_memcg_check() has no
callers.

So remove it.

No functional change.

Signed-off-by: Sang-Heon Jeon <ekffu200098@gmail.com>
---
 include/linux/memcontrol.h | 12 ------------
 1 file changed, 12 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 64c183be8cbf..b57a74617b0b 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -498,13 +498,6 @@ static inline struct mem_cgroup *folio_memcg_check(const struct folio *folio)
 	return obj_cgroup_memcg(objcg);
 }
 
-static inline struct mem_cgroup *page_memcg_check(const struct page *page)
-{
-	if (PageTail(page))
-		return NULL;
-	return folio_memcg_check((const struct folio *)page);
-}
-
 static inline struct mem_cgroup *get_mem_cgroup_from_objcg(const struct obj_cgroup *objcg)
 {
 	struct mem_cgroup *memcg;
@@ -1100,11 +1093,6 @@ static inline struct mem_cgroup *folio_memcg_check(const struct folio *folio)
 	return NULL;
 }
 
-static inline struct mem_cgroup *page_memcg_check(const struct page *page)
-{
-	return NULL;
-}
-
 static inline struct mem_cgroup *get_mem_cgroup_from_objcg(const struct obj_cgroup *objcg)
 {
 	return NULL;
-- 
2.43.0

Re: [PATCH 1/2] memcg: remove unused page_memcg_check()

[Shakeel Butt]

On Sat, Sep 19, 2026 at 01:55:57AM +0900, Sang-Heon Jeon wrote:
> Since commit 90f095b816e2 ("mm/page_owner: use memcg_data snapshot to
> avoid TOCTOU in print_page_owner_memcg()"), page_memcg_check() has no
> callers.
> 
> So remove it.
> 
> No functional change.
> 
> Signed-off-by: Sang-Heon Jeon <ekffu200098@gmail.com>

Acked-by: Shakeel Butt <shakeel.butt@linux.dev>

Re: [PATCH 1/2] memcg: remove unused page_memcg_check()

[SJ Park]

On Sat, 19 Sep 2026 01:55:57 +0900 Sang-Heon Jeon <ekffu200098@gmail.com> wrote:

> Since commit 90f095b816e2 ("mm/page_owner: use memcg_data snapshot to
> avoid TOCTOU in print_page_owner_memcg()"), page_memcg_check() has no
> callers.
> 
> So remove it.
> 
> No functional change.

Nice cleanup!

> 
> Signed-off-by: Sang-Heon Jeon <ekffu200098@gmail.com>

Reviewed-by: SJ Park <sj@kernel.org>


Thanks,
SJ

[...]

Re: [PATCH 1/2] memcg: remove unused page_memcg_check()

[Muchun Song]

> On Sep 19, 2026, at 00:55, Sang-Heon Jeon <ekffu200098@gmail.com> wrote:
> 
> Since commit 90f095b816e2 ("mm/page_owner: use memcg_data snapshot to
> avoid TOCTOU in print_page_owner_memcg()"), page_memcg_check() has no
> callers.
> 
> So remove it.
> 
> No functional change.
> 
> Signed-off-by: Sang-Heon Jeon <ekffu200098@gmail.com>

Acked-by: Muchun Song <muchun.song@linux.dev>

[PATCH 2/2] memcg: remove unused mod_memcg_page_state()

[Sang-Heon Jeon]

Since commit c466412c73c3 ("mm: memcontrol: switch to native NR_VMALLOC
vmstat counter"), mod_memcg_page_state() has no callers.

So remove it.

No functional change.

Signed-off-by: Sang-Heon Jeon <ekffu200098@gmail.com>
---
 include/linux/memcontrol.h | 20 --------------------
 1 file changed, 20 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index b57a74617b0b..c0557e1e3d21 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -949,21 +949,6 @@ void mem_cgroup_print_oom_group(struct mem_cgroup *memcg);
 void mod_memcg_state(struct mem_cgroup *memcg,
 		     enum memcg_stat_item idx, int val);
 
-static inline void mod_memcg_page_state(const struct page *page,
-					enum memcg_stat_item idx, int val)
-{
-	struct mem_cgroup *memcg;
-
-	if (mem_cgroup_disabled())
-		return;
-
-	rcu_read_lock();
-	memcg = folio_memcg(page_folio(page));
-	if (memcg)
-		mod_memcg_state(memcg, idx, val);
-	rcu_read_unlock();
-}
-
 unsigned long memcg_events(const struct mem_cgroup *memcg, int event);
 unsigned long memcg_page_state(const struct mem_cgroup *memcg, int idx);
 unsigned long memcg_page_state_output(const struct mem_cgroup *memcg, int item);
@@ -1396,11 +1381,6 @@ static inline void mod_memcg_state(struct mem_cgroup *memcg,
 {
 }
 
-static inline void mod_memcg_page_state(const struct page *page,
-					enum memcg_stat_item idx, int val)
-{
-}
-
 static inline unsigned long memcg_page_state(const struct mem_cgroup *memcg, int idx)
 {
 	return 0;
-- 
2.43.0

Re: [PATCH 2/2] memcg: remove unused mod_memcg_page_state()

[Shakeel Butt]

On Sat, Sep 19, 2026 at 01:55:58AM +0900, Sang-Heon Jeon wrote:
> Since commit c466412c73c3 ("mm: memcontrol: switch to native NR_VMALLOC
> vmstat counter"), mod_memcg_page_state() has no callers.
> 
> So remove it.
> 
> No functional change.
> 
> Signed-off-by: Sang-Heon Jeon <ekffu200098@gmail.com>

Acked-by: Shakeel Butt <shakeel.butt@linux.dev>

Re: [PATCH 2/2] memcg: remove unused mod_memcg_page_state()

[SJ Park]

On Sat, 19 Sep 2026 01:55:58 +0900 Sang-Heon Jeon <ekffu200098@gmail.com> wrote:

> Since commit c466412c73c3 ("mm: memcontrol: switch to native NR_VMALLOC
> vmstat counter"), mod_memcg_page_state() has no callers.
> 
> So remove it.
> 
> No functional change.

Nice cleanup!

> 
> Signed-off-by: Sang-Heon Jeon <ekffu200098@gmail.com>

Reviewed-by: SJ Park <sj@kernel.org>


Thanks,
SJ

[...]

Re: [PATCH 2/2] memcg: remove unused mod_memcg_page_state()

[Muchun Song]

> On Sep 19, 2026, at 00:55, Sang-Heon Jeon <ekffu200098@gmail.com> wrote:
> 
> Since commit c466412c73c3 ("mm: memcontrol: switch to native NR_VMALLOC
> vmstat counter"), mod_memcg_page_state() has no callers.
> 
> So remove it.
> 
> No functional change.
> 
> Signed-off-by: Sang-Heon Jeon <ekffu200098@gmail.com>

Acked-by: Muchun Song <muchun.song@linux.dev>