Each time SECTIONS_PER_ROOT number of mem_section is allocated when
mem_section[root] is null. This means only (1 / SECTIONS_PER_ROOT) chance
of the mem_section[root] check is false.

This patch adds likely to the if check to optimize this a little.

Signed-off-by: Wei Yang <redacted>
---
 mm/sparse.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/sparse.c b/mm/sparse.c
index 10b07eea9a6e..90bab7f03757 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c

@@ -78,7 +78,7 @@ static int __meminit sparse_index_init(unsigned long section_nr, int nid)
 	unsigned long root = SECTION_NR_TO_ROOT(section_nr);
 	struct mem_section *section;
 
-	if (mem_section[root])
+	if (likely(mem_section[root]))
 		return -EEXIST;
 
 	section = sparse_index_alloc(nid);

-- 
2.15.1