mm: memcg: move vmstats structs definition above flushing code

The following patch will make use of those structs in the flushing code,
so move their definitions (and a few other dependencies) a little bit up
to reduce the diff noise in the following patch.

No functional change intended.

Link: https://lkml.kernel.org/r/20231129032154.3710765-3-yosryahmed@google.comSigned-off-by: Yosry Ahmed <yosryahmed@google.com>
Tested-by: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Greg Thelen <gthelen@google.com>
Cc: Ivan Babrou <ivan@cloudflare.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Koutny <mkoutny@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Tejun Heo <tj@kernel.org>
Cc: Waiman Long <longman@redhat.com>
Cc: Wei Xu <weixugc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/memcontrol.c

@@ -573,6 +573,80 @@ mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node *mctz)
 	return mz;
 }
 
+/* Subset of vm_event_item to report for memcg event stats */
+static const unsigned int memcg_vm_event_stat[] = {
+	PGPGIN,
+	PGPGOUT,
+	PGSCAN_KSWAPD,
+	PGSCAN_DIRECT,
+	PGSCAN_KHUGEPAGED,
+	PGSTEAL_KSWAPD,
+	PGSTEAL_DIRECT,
+	PGSTEAL_KHUGEPAGED,
+	PGFAULT,
+	PGMAJFAULT,
+	PGREFILL,
+	PGACTIVATE,
+	PGDEACTIVATE,
+	PGLAZYFREE,
+	PGLAZYFREED,
+#if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_ZSWAP)
+	ZSWPIN,
+	ZSWPOUT,
+	ZSWPWB,
+#endif
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+	THP_FAULT_ALLOC,
+	THP_COLLAPSE_ALLOC,
+	THP_SWPOUT,
+	THP_SWPOUT_FALLBACK,
+#endif
+};
+
+#define NR_MEMCG_EVENTS ARRAY_SIZE(memcg_vm_event_stat)
+static int mem_cgroup_events_index[NR_VM_EVENT_ITEMS] __read_mostly;
+
+static void init_memcg_events(void)
+{
+	int i;
+
+	for (i = 0; i < NR_MEMCG_EVENTS; ++i)
+		mem_cgroup_events_index[memcg_vm_event_stat[i]] = i + 1;
+}
+
+static inline int memcg_events_index(enum vm_event_item idx)
+{
+	return mem_cgroup_events_index[idx] - 1;
+}
+
+struct memcg_vmstats_percpu {
+	/* Local (CPU and cgroup) page state & events */
+	long			state[MEMCG_NR_STAT];
+	unsigned long		events[NR_MEMCG_EVENTS];
+
+	/* Delta calculation for lockless upward propagation */
+	long			state_prev[MEMCG_NR_STAT];
+	unsigned long		events_prev[NR_MEMCG_EVENTS];
+
+	/* Cgroup1: threshold notifications & softlimit tree updates */
+	unsigned long		nr_page_events;
+	unsigned long		targets[MEM_CGROUP_NTARGETS];
+};
+
+struct memcg_vmstats {
+	/* Aggregated (CPU and subtree) page state & events */
+	long			state[MEMCG_NR_STAT];
+	unsigned long		events[NR_MEMCG_EVENTS];
+
+	/* Non-hierarchical (CPU aggregated) page state & events */
+	long			state_local[MEMCG_NR_STAT];
+	unsigned long		events_local[NR_MEMCG_EVENTS];
+
+	/* Pending child counts during tree propagation */
+	long			state_pending[MEMCG_NR_STAT];
+	unsigned long		events_pending[NR_MEMCG_EVENTS];
+};
+
 /*
  * memcg and lruvec stats flushing
  *
@@ -684,80 +758,6 @@ static void flush_memcg_stats_dwork(struct work_struct *w)
 	queue_delayed_work(system_unbound_wq, &stats_flush_dwork, FLUSH_TIME);
 }
 
-/* Subset of vm_event_item to report for memcg event stats */
-static const unsigned int memcg_vm_event_stat[] = {
-	PGPGIN,
-	PGPGOUT,
-	PGSCAN_KSWAPD,
-	PGSCAN_DIRECT,
-	PGSCAN_KHUGEPAGED,
-	PGSTEAL_KSWAPD,
-	PGSTEAL_DIRECT,
-	PGSTEAL_KHUGEPAGED,
-	PGFAULT,
-	PGMAJFAULT,
-	PGREFILL,
-	PGACTIVATE,
-	PGDEACTIVATE,
-	PGLAZYFREE,
-	PGLAZYFREED,
-#if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_ZSWAP)
-	ZSWPIN,
-	ZSWPOUT,
-	ZSWPWB,
-#endif
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
-	THP_FAULT_ALLOC,
-	THP_COLLAPSE_ALLOC,
-	THP_SWPOUT,
-	THP_SWPOUT_FALLBACK,
-#endif
-};
-
-#define NR_MEMCG_EVENTS ARRAY_SIZE(memcg_vm_event_stat)
-static int mem_cgroup_events_index[NR_VM_EVENT_ITEMS] __read_mostly;
-
-static void init_memcg_events(void)
-{
-	int i;
-
-	for (i = 0; i < NR_MEMCG_EVENTS; ++i)
-		mem_cgroup_events_index[memcg_vm_event_stat[i]] = i + 1;
-}
-
-static inline int memcg_events_index(enum vm_event_item idx)
-{
-	return mem_cgroup_events_index[idx] - 1;
-}
-
-struct memcg_vmstats_percpu {
-	/* Local (CPU and cgroup) page state & events */
-	long			state[MEMCG_NR_STAT];
-	unsigned long		events[NR_MEMCG_EVENTS];
-
-	/* Delta calculation for lockless upward propagation */
-	long			state_prev[MEMCG_NR_STAT];
-	unsigned long		events_prev[NR_MEMCG_EVENTS];
-
-	/* Cgroup1: threshold notifications & softlimit tree updates */
-	unsigned long		nr_page_events;
-	unsigned long		targets[MEM_CGROUP_NTARGETS];
-};
-
-struct memcg_vmstats {
-	/* Aggregated (CPU and subtree) page state & events */
-	long			state[MEMCG_NR_STAT];
-	unsigned long		events[NR_MEMCG_EVENTS];
-
-	/* Non-hierarchical (CPU aggregated) page state & events */
-	long			state_local[MEMCG_NR_STAT];
-	unsigned long		events_local[NR_MEMCG_EVENTS];
-
-	/* Pending child counts during tree propagation */
-	long			state_pending[MEMCG_NR_STAT];
-	unsigned long		events_pending[NR_MEMCG_EVENTS];
-};
-
 unsigned long memcg_page_state(struct mem_cgroup *memcg, int idx)
 {
 	long x = READ_ONCE(memcg->vmstats->state[idx]);