[PATCH 01/27] mm, page_alloc: Use ac->classzone_idx instead of zone_idx(preferred_zone)

[Mel Gorman]

ac->classzone_idx is determined by the index of the preferred zone and cached
to avoid repeated calculations. wake_all_kswapds() should use it instead of
using zone_idx() within a loop.

Signed-off-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
---
 mm/page_alloc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 59de90d5d3a3..2643d10dee98 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3049,7 +3049,7 @@ static void wake_all_kswapds(unsigned int order, const struct alloc_context *ac)
 
 	for_each_zone_zonelist_nodemask(zone, z, ac->zonelist,
 						ac->high_zoneidx, ac->nodemask)
-		wakeup_kswapd(zone, order, zone_idx(ac->preferred_zone));
+		wakeup_kswapd(zone, order, ac->classzone_idx);
 }
 
 static inline int
-- 
2.6.4