[PATCH 2/4] vmscan: make lru_index() helper function

[KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>]

Current lru calculation (e.g. LRU_ACTIVE + file * LRU_FILE) is a bit
ugly.
To make helper function improve code readability a bit.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
---
 mm/vmscan.c |   25 ++++++++++++++-----------
 1 files changed, 14 insertions(+), 11 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index a58ff15..7e0245d 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -156,6 +156,16 @@ static unsigned long zone_nr_lru_pages(struct zone *zone,
 	return zone_page_state(zone, NR_LRU_BASE + lru);
 }
 
+static inline enum lru_list lru_index(int active, int file)
+{
+	int lru = LRU_BASE;
+	if (active)
+		lru += LRU_ACTIVE;
+	if (file)
+		lru += LRU_FILE;
+
+	return lru;
+}
 
 /*
  * Add a shrinker callback to be called from the vm
@@ -978,13 +988,8 @@ static unsigned long isolate_pages_global(unsigned long nr,
 					struct mem_cgroup *mem_cont,
 					int active, int file)
 {
-	int lru = LRU_BASE;
-	if (active)
-		lru += LRU_ACTIVE;
-	if (file)
-		lru += LRU_FILE;
-	return isolate_lru_pages(nr, &z->lru[lru].list, dst, scanned, order,
-								mode, file);
+	return isolate_lru_pages(nr, &z->lru[lru_index(active, file)].list,
+				 dst, scanned, order, mode, file);
 }
 
 /*
@@ -1373,10 +1378,8 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone,
 	 */
 	reclaim_stat->recent_rotated[file] += nr_rotated;
 
-	move_active_pages_to_lru(zone, &l_active,
-						LRU_ACTIVE + file * LRU_FILE);
-	move_active_pages_to_lru(zone, &l_inactive,
-						LRU_BASE   + file * LRU_FILE);
+	move_active_pages_to_lru(zone, &l_active, lru_index(1, file));
+	move_active_pages_to_lru(zone, &l_inactive, lru_index(0, file));
 	__mod_zone_page_state(zone, NR_ISOLATED_ANON + file, -nr_taken);
 	spin_unlock_irq(&zone->lru_lock);
 }
-- 
1.6.5.2



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