mm/vmscan.c: simplify shrink_inactive_list()

This merges together duplicated patterns of code.  Also, replace
count_memcg_events() with its irq-careless namesake, because they are
already called in interrupts disabled context.

Link: http://lkml.kernel.org/r/2ece1df4-2989-bc9b-6172-61e9fdde5bfd@virtuozzo.com
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Santhosh <san8754513543@gmail.com>

Author: Kirill Tkhai

mm/vmscan.c

@@ -1977,6 +1977,7 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec,
 	struct reclaim_stat stat = {};
 	isolate_mode_t isolate_mode = 0;
 	int file = is_file_lru(lru);
+	enum vm_event_item item;
 	struct pglist_data *pgdat = lruvec_pgdat(lruvec);
 	struct zone_reclaim_stat *reclaim_stat = &lruvec->reclaim_stat;
 	bool stalled = false;
@@ -2007,17 +2008,10 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec,
 	__mod_node_page_state(pgdat, NR_ISOLATED_ANON + file, nr_taken);
 	reclaim_stat->recent_scanned[file] += nr_taken;
 
-	if (current_is_kswapd()) {
-		if (global_reclaim(sc))
-			__count_vm_events(PGSCAN_KSWAPD, nr_scanned);
-		count_memcg_events(lruvec_memcg(lruvec), PGSCAN_KSWAPD,
-				   nr_scanned);
-	} else {
-		if (global_reclaim(sc))
-			__count_vm_events(PGSCAN_DIRECT, nr_scanned);
-		count_memcg_events(lruvec_memcg(lruvec), PGSCAN_DIRECT,
-				   nr_scanned);
-	}
+	item = current_is_kswapd() ? PGSCAN_KSWAPD : PGSCAN_DIRECT;
+	if (global_reclaim(sc))
+		__count_vm_events(item, nr_scanned);
+	__count_memcg_events(lruvec_memcg(lruvec), item, nr_scanned);
 	spin_unlock_irq(&pgdat->lru_lock);
 
 	if (nr_taken == 0)
@@ -2028,17 +2022,10 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec,
 
 	spin_lock_irq(&pgdat->lru_lock);
 
-	if (current_is_kswapd()) {
-		if (global_reclaim(sc))
-			__count_vm_events(PGSTEAL_KSWAPD, nr_reclaimed);
-		count_memcg_events(lruvec_memcg(lruvec), PGSTEAL_KSWAPD,
-				   nr_reclaimed);
-	} else {
-		if (global_reclaim(sc))
-			__count_vm_events(PGSTEAL_DIRECT, nr_reclaimed);
-		count_memcg_events(lruvec_memcg(lruvec), PGSTEAL_DIRECT,
-				   nr_reclaimed);
-	}
+	item = current_is_kswapd() ? PGSTEAL_KSWAPD : PGSTEAL_DIRECT;
+	if (global_reclaim(sc))
+		__count_vm_events(item, nr_reclaimed);
+	__count_memcg_events(lruvec_memcg(lruvec), item, nr_reclaimed);
 
 	putback_inactive_pages(lruvec, &page_list);
 
@@ -2133,7 +2120,7 @@ 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,
+		__count_memcg_events(lruvec_memcg(lruvec), PGDEACTIVATE,
 				   nr_moved);
 	}
 
@@ -2173,7 +2160,7 @@ static void shrink_active_list(unsigned long nr_to_scan,
 	reclaim_stat->recent_scanned[file] += nr_taken;
 
 	__count_vm_events(PGREFILL, nr_scanned);
-	count_memcg_events(lruvec_memcg(lruvec), PGREFILL, nr_scanned);
+	__count_memcg_events(lruvec_memcg(lruvec), PGREFILL, nr_scanned);
 
 	spin_unlock_irq(&pgdat->lru_lock);