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

[Joonsoo Kim]

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;
 
 		BUILD_BUG_ON(ALLOC_NO_WATERMARKS < NR_WMARK);
-		if (!(alloc_flags & ALLOC_NO_WATERMARKS)) {
+		if (likely(!(alloc_flags & ALLOC_NO_WATERMARKS))) {
 			unsigned long mark;
 			int ret;
 
-- 
1.7.9.5

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