[PATCH v3] mm: Simplify shrink_inactive_list()

[Kirill Tkhai <ktkhai@virtuozzo.com>]

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

Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Acked-by: Michal Hocko <mhocko@suse.com>

v3: Advance changelog.
v2: Introduce local variable.
---
 mm/vmscan.c |   31 +++++++++----------------------
 1 file changed, 9 insertions(+), 22 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 836b28913bd7..d96efff59a11 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1907,6 +1907,7 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec,
 	unsigned long nr_taken;
 	struct reclaim_stat stat;
 	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;
@@ -1934,17 +1935,10 @@ 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)
@@ -1955,17 +1949,10 @@ 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);
 	reclaim_stat->recent_rotated[0] = stat.nr_activate[0];
 	reclaim_stat->recent_rotated[1] = stat.nr_activate[1];