From ef0d65a5f4df1cfe51a91df892ebbb16ea1c182b Mon Sep 17 00:00:00 2001 From: Andrea Arcangeli Date: Fri, 20 May 2016 16:58:24 -0700 Subject: [PATCH] mm: thp: microoptimize compound_mapcount() compound_mapcount() is only called after PageCompound() has already been checked by the caller, so there's no point to check it again. Gcc may optimize it away too because it's inline but this will remove the runtime check for sure and add it'll add an assert instead. Link: http://lkml.kernel.org/r/1462547040-1737-3-git-send-email-aarcange@redhat.com Signed-off-by: Andrea Arcangeli Acked-by: Kirill A. Shutemov Cc: Alex Williamson Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/mm.h | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 2b97be1147ecf..65d18a45b8e84 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -475,8 +475,7 @@ static inline atomic_t *compound_mapcount_ptr(struct page *page) static inline int compound_mapcount(struct page *page) { - if (!PageCompound(page)) - return 0; + VM_BUG_ON_PAGE(!PageCompound(page), page); page = compound_head(page); return atomic_read(compound_mapcount_ptr(page)) + 1; } -- 2.39.5