vmscan: Use an indexed array for LRU variables

Currently we are defining explicit variables for the inactive and active
list.  An indexed array can be more generic and avoid repeating similar
code in several places in the reclaim code.

We are saving a few bytes in terms of code size:

Before:

   text    data     bss     dec     hex filename
4097753  573120 4092484 8763357  85b7dd vmlinux

After:

   text    data     bss     dec     hex filename
4097729  573120 4092484 8763333  85b7c5 vmlinux

Having an easy way to add new lru lists may ease future work on the
reclaim code.

Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 5 insertions, 4 deletions

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 9eb9eb928285..ee7a96ef40dc 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3414,6 +3414,7 @@ static void __paginginit free_area_init_core(struct pglist_data *pgdat,
         for (j = 0; j < MAX_NR_ZONES; j++) {
                 struct zone *zone = pgdat->node_zones + j;
                 unsigned long size, realsize, memmap_pages;
+                enum lru_list l;
 
                 size = zone_spanned_pages_in_node(nid, j, zones_size);
                 realsize = size - zone_absent_pages_in_node(nid, j,
@@ -3465,10 +3466,10 @@ static void __paginginit free_area_init_core(struct pglist_data *pgdat,
                 zone->prev_priority = DEF_PRIORITY;
 
                 zone_pcp_init(zone);
-                INIT_LIST_HEAD(&zone->active_list);
-                INIT_LIST_HEAD(&zone->inactive_list);
-                zone->nr_scan_active = 0;
-                zone->nr_scan_inactive = 0;
+                for_each_lru(l) {
+                        INIT_LIST_HEAD(&zone->lru[l].list);
+                        zone->lru[l].nr_scan = 0;
+                }
                 zap_zone_vm_stats(zone);
                 zone->flags = 0;
                 if (!size)