vmscan: remove dead code in shrink_inactive_list()

After synchrounous lumpy reclaim, the page_list is guaranteed to not have
active pages as page activation in shrink_page_list() disables lumpy
reclaim.  Remove the dead code.
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/vmscan.c

@@ -1331,7 +1331,6 @@ shrink_inactive_list(unsigned long nr_to_scan, struct zone *zone,
 	unsigned long nr_scanned;
 	unsigned long nr_reclaimed = 0;
 	unsigned long nr_taken;
-	unsigned long nr_active;
 	unsigned long nr_anon;
 	unsigned long nr_file;
 
@@ -1386,13 +1385,6 @@ shrink_inactive_list(unsigned long nr_to_scan, struct zone *zone,
 
 	/* Check if we should syncronously wait for writeback */
 	if (should_reclaim_stall(nr_taken, nr_reclaimed, priority, sc)) {
-		/*
-		 * The attempt at page out may have made some
-		 * of the pages active, mark them inactive again.
-		 */
-		nr_active = clear_active_flags(&page_list, NULL);
-		count_vm_events(PGDEACTIVATE, nr_active);
-
 		set_lumpy_reclaim_mode(priority, sc, true);
 		nr_reclaimed += shrink_page_list(&page_list, sc);
 	}