[PATCH, RFC 02/10] mm: change PageAnon() to work on tail pages

["Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>]

Current PageAnon() is always return false for tail. We need to look on
head page for correct answer. Let's change the function to give the
right result.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 include/linux/mm.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 9f4960bf505b..a60e2db5f9f9 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -983,6 +983,7 @@ struct address_space *page_file_mapping(struct page *page)
 
 static inline int PageAnon(struct page *page)
 {
+	page = compound_head(page);
 	return ((unsigned long)page->mapping & PAGE_MAPPING_ANON) != 0;
 }
 
-- 
2.0.0.rc4