mm: move nr_deactivate accounting to shrink_active_list()

We know which LRU is not active.

[chris@chrisdown.name: fix build on !CONFIG_MEMCG]
  Link: http://lkml.kernel.org/r/20190322150513.GA22021@chrisdown.name
Link: http://lkml.kernel.org/r/155290128498.31489.18250485448913338607.stgit@localhost.localdomainSigned-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: Chris Down <chris@chrisdown.name>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/memcontrol.h

@@ -1117,6 +1117,12 @@ static inline void count_memcg_events(struct mem_cgroup *memcg,
 {
 }
 
+static inline void __count_memcg_events(struct mem_cgroup *memcg,
+					enum vm_event_item idx,
+					unsigned long count)
+{
+}
+
 static inline void count_memcg_page_event(struct page *page,
 					  int idx)
 {

mm/vmscan.c

@@ -2040,12 +2040,6 @@ static unsigned move_active_pages_to_lru(struct lruvec *lruvec,
 		}
 	}
 
-	if (!is_active_lru(lru)) {
-		__count_vm_events(PGDEACTIVATE, nr_moved);
-		count_memcg_events(lruvec_memcg(lruvec), PGDEACTIVATE,
-				   nr_moved);
-	}
-
 	return nr_moved;
 }
 
@@ -2137,6 +2131,10 @@ static void shrink_active_list(unsigned long nr_to_scan,
 
 	nr_activate = move_active_pages_to_lru(lruvec, &l_active, &l_hold, lru);
 	nr_deactivate = move_active_pages_to_lru(lruvec, &l_inactive, &l_hold, lru - LRU_ACTIVE);
+
+	__count_vm_events(PGDEACTIVATE, nr_deactivate);
+	__count_memcg_events(lruvec_memcg(lruvec), PGDEACTIVATE, nr_deactivate);
+
 	__mod_node_page_state(pgdat, NR_ISOLATED_ANON + file, -nr_taken);
 	spin_unlock_irq(&pgdat->lru_lock);