[PATCH 1/4] mm, page_alloc: add likely macro to help compiler optimization

From: Joonsoo Kim
Date: Thu Aug 01 2013 - 22:08:09 EST

We rarely allocate a page with ALLOC_NO_WATERMARKS and it is used
in slow path. For making fast path more faster, add likely macro to
help compiler optimization.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index b100255..86ad44b 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1901,7 +1901,7 @@ zonelist_scan:
goto this_zone_full;

- if (!(alloc_flags & ALLOC_NO_WATERMARKS)) {
+ if (likely(!(alloc_flags & ALLOC_NO_WATERMARKS))) {
unsigned long mark;
int ret;


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