[PATCH v2] change alloc function in alloc_slab_page

[Minchan Kim <minchan.kim@gmail.com>]

V2
* change changelog
* Add some reviewed-by 

alloc_slab_page always checks nid == -1, so alloc_page_node can't be
called with -1. 
It means node's validity check in alloc_pages_node is unnecessary. 
So we can use alloc_pages_exact_node instead of alloc_pages_node. 
It could avoid comparison and branch as 6484eb3e2a81807722 tried.

Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Mel Gorman <mel@csn.ul.ie>
---
 mm/slub.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/mm/slub.c b/mm/slub.c
index b364844..9984165 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1084,7 +1084,7 @@ static inline struct page *alloc_slab_page(gfp_t flags, int node,
 	if (node == -1)
 		return alloc_pages(flags, order);
 	else
-		return alloc_pages_node(node, flags, order);
+		return alloc_pages_exact_node(node, flags, order);
 }
 
 static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
-- 
1.7.0.5