| From | "Kirill A. Shutemov" <> | Subject | [PATCH 15/16] page-flags: look on head page if the flag is encoded in page->mapping | Date | Thu, 19 Mar 2015 19:08:21 +0200 |
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PageAnon() and PageKsm() look on lower bits of page->mapping to check if the page is Anon or KSM. page->mapping can be overloaded in tail pages.
Let's always look on head page to avoid false-positives.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> --- include/linux/page-flags.h | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index 55a69c40e4ae..07fa2781df23 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -385,6 +385,7 @@ PAGEFLAG_FALSE(HWPoison) static inline int PageAnon(struct page *page) { + page = compound_head(page); return ((unsigned long)page->mapping & PAGE_MAPPING_ANON) != 0; } @@ -397,6 +398,7 @@ static inline int PageAnon(struct page *page) */ static inline int PageKsm(struct page *page) { + page = compound_head(page); return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) == (PAGE_MAPPING_ANON | PAGE_MAPPING_KSM); } -- 2.1.4
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