mm: memcontrol: privatize memcg_page_state query functions

mainline inclusion
from mainline-v5.13-rc1
commit a18e6e6e
category: feature
bugzilla: 185803 https://gitee.com/openeuler/kernel/issues/I4JOG9?from=project-issue
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=a18e6e6e150a

-------------------------------------------------------------------

There are no users outside of the memory controller itself. The rest
of the kernel cares either about node or lruvec stats.

Link: https://lkml.kernel.org/r/20210209163304.77088-4-hannes@cmpxchg.orgSigned-off-by: NJohannes Weiner <hannes@cmpxchg.org>
Reviewed-by: NShakeel Butt <shakeelb@google.com>
Reviewed-by: NRoman Gushchin <guro@fb.com>
Acked-by: NMichal Hocko <mhocko@suse.com>
Reviewed-by: NMichal Koutný <mkoutny@suse.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Conflict:
	include/linux/memcontrol.h
Signed-off-by: NLu Jialin <lujialin4@huawei.com>
Reviewed-by: NXiu Jianfeng <xiujianfeng@huawei.com>
Reviewed-by: NKefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

include/linux/memcontrol.h

@@ -978,39 +978,6 @@ struct mem_cgroup *lock_page_memcg(struct page *page);
 void __unlock_page_memcg(struct mem_cgroup *memcg);
 void unlock_page_memcg(struct page *page);
 
-/*
- * idx can be of type enum memcg_stat_item or node_stat_item.
- * Keep in sync with memcg_exact_page_state().
- */
-static inline unsigned long memcg_page_state(struct mem_cgroup *memcg, int idx)
-{
-	long x = atomic_long_read(&memcg->vmstats[idx]);
-#ifdef CONFIG_SMP
-	if (x < 0)
-		x = 0;
-#endif
-	return x;
-}
-
-/*
- * idx can be of type enum memcg_stat_item or node_stat_item.
- * Keep in sync with memcg_exact_page_state().
- */
-static inline unsigned long memcg_page_state_local(struct mem_cgroup *memcg,
-						   int idx)
-{
-	long x = 0;
-	int cpu;
-
-	for_each_possible_cpu(cpu)
-		x += per_cpu(memcg->vmstats_local->stat[idx], cpu);
-#ifdef CONFIG_SMP
-	if (x < 0)
-		x = 0;
-#endif
-	return x;
-}
-
 void __mod_memcg_state(struct mem_cgroup *memcg, int idx, int val);
 
 /* idx can be of type enum memcg_stat_item or node_stat_item */
@@ -1528,17 +1495,6 @@ static inline void mem_cgroup_print_oom_group(struct mem_cgroup *memcg)
 {
 }
 
-static inline unsigned long memcg_page_state(struct mem_cgroup *memcg, int idx)
-{
-	return 0;
-}
-
-static inline unsigned long memcg_page_state_local(struct mem_cgroup *memcg,
-						   int idx)
-{
-	return 0;
-}
-
 static inline void __mod_memcg_state(struct mem_cgroup *memcg,
 				     int idx,
 				     int nr)

mm/memcontrol.c

@@ -668,6 +668,38 @@ void __mod_memcg_state(struct mem_cgroup *memcg, int idx, int val)
 	__this_cpu_write(memcg->vmstats_percpu->stat[idx], x);
 }
 
+/*
+ * idx can be of type enum memcg_stat_item or node_stat_item.
+ * Keep in sync with memcg_exact_page_state().
+ */
+static unsigned long memcg_page_state(struct mem_cgroup *memcg, int idx)
+{
+	long x = atomic_long_read(&memcg->vmstats[idx]);
+#ifdef CONFIG_SMP
+	if (x < 0)
+		x = 0;
+#endif
+	return x;
+}
+
+/*
+ * idx can be of type enum memcg_stat_item or node_stat_item.
+ * Keep in sync with memcg_exact_page_state().
+ */
+static unsigned long memcg_page_state_local(struct mem_cgroup *memcg, int idx)
+{
+	long x = 0;
+	int cpu;
+
+	for_each_possible_cpu(cpu)
+		x += per_cpu(memcg->vmstats_local->stat[idx], cpu);
+#ifdef CONFIG_SMP
+	if (x < 0)
+		x = 0;
+#endif
+	return x;
+}
+
 static struct mem_cgroup_per_node *
 parent_nodeinfo(struct mem_cgroup_per_node *pn, int nid)
 {