Messages in this thread Patch in this message | | | From | "Kirill A. Shutemov" <> | Subject | [PATCH 15/16] page-flags: look at head page if the flag is encoded in page->mapping | Date | Thu, 24 Sep 2015 17:51:03 +0300 |
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PageAnon() and PageKsm() look at 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 at 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 e3ccd95de660..6f5df65d1038 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -369,6 +369,7 @@ PAGEFLAG(Idle, idle, PF_ANY) static inline int PageAnon(struct page *page) { + page = compound_head(page); return ((unsigned long)page->mapping & PAGE_MAPPING_ANON) != 0; } @@ -381,6 +382,7 @@ 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); } -- 2.5.1
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