memcg: make v1 only functions static

The functions memcg1_charge_statistics() and memcg1_check_events() are
never used outside of v1 source file.  So, make them static.

Link: https://lkml.kernel.org/r/20240815050453.1298138-6-shakeel.butt@linux.devSigned-off-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: T.J. Mercier <tjmercier@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/memcontrol-v1.c

@@ -742,6 +742,9 @@ static struct page *mc_handle_file_pte(struct vm_area_struct *vma,
 	return folio_file_page(folio, index);
 }
 
+static void memcg1_check_events(struct mem_cgroup *memcg, int nid);
+static void memcg1_charge_statistics(struct mem_cgroup *memcg, int nr_pages);
+
 /**
  * mem_cgroup_move_account - move account of the folio
  * @folio: The folio.
@@ -1439,7 +1442,7 @@ static void mem_cgroup_threshold(struct mem_cgroup *memcg)
 	}
 }
 
-void memcg1_charge_statistics(struct mem_cgroup *memcg, int nr_pages)
+static void memcg1_charge_statistics(struct mem_cgroup *memcg, int nr_pages)
 {
 	/* pagein of a big page is an event. So, ignore page size */
 	if (nr_pages > 0)
@@ -1484,7 +1487,7 @@ static bool memcg1_event_ratelimit(struct mem_cgroup *memcg,
  * Check events in order.
  *
  */
-void memcg1_check_events(struct mem_cgroup *memcg, int nid)
+static void memcg1_check_events(struct mem_cgroup *memcg, int nid)
 {
 	if (IS_ENABLED(CONFIG_PREEMPT_RT))
 		return;

mm/memcontrol-v1.h

@@ -115,9 +115,6 @@ bool memcg1_oom_prepare(struct mem_cgroup *memcg, bool *locked);
 void memcg1_oom_finish(struct mem_cgroup *memcg, bool locked);
 void memcg1_oom_recover(struct mem_cgroup *memcg);
 
-void memcg1_charge_statistics(struct mem_cgroup *memcg, int nr_pages);
-void memcg1_check_events(struct mem_cgroup *memcg, int nid);
-
 void memcg1_commit_charge(struct folio *folio, struct mem_cgroup *memcg);
 void memcg1_swapout(struct folio *folio, struct mem_cgroup *memcg);
 void memcg1_uncharge_batch(struct mem_cgroup *memcg, unsigned long pgpgout,
@@ -152,9 +149,6 @@ static inline bool memcg1_oom_prepare(struct mem_cgroup *memcg, bool *locked) {
 static inline void memcg1_oom_finish(struct mem_cgroup *memcg, bool locked) {}
 static inline void memcg1_oom_recover(struct mem_cgroup *memcg) {}
 
-static inline void memcg1_charge_statistics(struct mem_cgroup *memcg, int nr_pages) {}
-static inline void memcg1_check_events(struct mem_cgroup *memcg, int nid) {}
-
 static inline void memcg1_commit_charge(struct folio *folio,
 					struct mem_cgroup *memcg) {}