memcg: move mem_cgroup_event_ratelimit to v1 code

There are no callers of mem_cgroup_event_ratelimit() in the v2 code.  Move
it to v1 only code and rename it to memcg1_event_ratelimit().

Link: https://lkml.kernel.org/r/20240815050453.1298138-3-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

@@ -1439,6 +1439,34 @@ static void mem_cgroup_threshold(struct mem_cgroup *memcg)
 	}
 }
 
+#define THRESHOLDS_EVENTS_TARGET 128
+#define SOFTLIMIT_EVENTS_TARGET 1024
+
+static bool memcg1_event_ratelimit(struct mem_cgroup *memcg,
+				enum mem_cgroup_events_target target)
+{
+	unsigned long val, next;
+
+	val = __this_cpu_read(memcg->events_percpu->nr_page_events);
+	next = __this_cpu_read(memcg->events_percpu->targets[target]);
+	/* from time_after() in jiffies.h */
+	if ((long)(next - val) < 0) {
+		switch (target) {
+		case MEM_CGROUP_TARGET_THRESH:
+			next = val + THRESHOLDS_EVENTS_TARGET;
+			break;
+		case MEM_CGROUP_TARGET_SOFTLIMIT:
+			next = val + SOFTLIMIT_EVENTS_TARGET;
+			break;
+		default:
+			break;
+		}
+		__this_cpu_write(memcg->events_percpu->targets[target], next);
+		return true;
+	}
+	return false;
+}
+
 /*
  * Check events in order.
  *
@@ -1449,11 +1477,11 @@ void memcg1_check_events(struct mem_cgroup *memcg, int nid)
 		return;
 
 	/* threshold event is triggered in finer grain than soft limit */
-	if (unlikely(mem_cgroup_event_ratelimit(memcg,
+	if (unlikely(memcg1_event_ratelimit(memcg,
 						MEM_CGROUP_TARGET_THRESH))) {
 		bool do_softlimit;
 
-		do_softlimit = mem_cgroup_event_ratelimit(memcg,
+		do_softlimit = memcg1_event_ratelimit(memcg,
 						MEM_CGROUP_TARGET_SOFTLIMIT);
 		mem_cgroup_threshold(memcg);
 		if (unlikely(do_softlimit))

mm/memcontrol-v1.h

@@ -62,8 +62,6 @@ struct memcg1_events_percpu {
 	unsigned long targets[MEM_CGROUP_NTARGETS];
 };
 
-bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg,
-				enum mem_cgroup_events_target target);
 unsigned long mem_cgroup_usage(struct mem_cgroup *memcg, bool swap);
 
 void drain_all_stock(struct mem_cgroup *root_memcg);

mm/memcontrol.c

@@ -95,9 +95,6 @@ static bool cgroup_memory_nobpf __ro_after_init;
 static DECLARE_WAIT_QUEUE_HEAD(memcg_cgwb_frn_waitq);
 #endif
 
-#define THRESHOLDS_EVENTS_TARGET 128
-#define SOFTLIMIT_EVENTS_TARGET 1024
-
 static inline bool task_is_dying(void)
 {
 	return tsk_is_oom_victim(current) || fatal_signal_pending(current) ||
@@ -856,31 +853,6 @@ void mem_cgroup_charge_statistics(struct mem_cgroup *memcg, int nr_pages)
 	__this_cpu_add(memcg->events_percpu->nr_page_events, nr_pages);
 }
 
-bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg,
-				enum mem_cgroup_events_target target)
-{
-	unsigned long val, next;
-
-	val = __this_cpu_read(memcg->events_percpu->nr_page_events);
-	next = __this_cpu_read(memcg->events_percpu->targets[target]);
-	/* from time_after() in jiffies.h */
-	if ((long)(next - val) < 0) {
-		switch (target) {
-		case MEM_CGROUP_TARGET_THRESH:
-			next = val + THRESHOLDS_EVENTS_TARGET;
-			break;
-		case MEM_CGROUP_TARGET_SOFTLIMIT:
-			next = val + SOFTLIMIT_EVENTS_TARGET;
-			break;
-		default:
-			break;
-		}
-		__this_cpu_write(memcg->events_percpu->targets[target], next);
-		return true;
-	}
-	return false;
-}
-
 struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
 {
 	/*