[PATCH 17 of 25] clear page compound

Andrea Arcangeli
2009-11-14T18:10:25Z

split_huge_page must transform a compound page to a regular page and needs
ClearPageCompound.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
---

diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -347,7 +347,7 @@ static inline void set_page_writeback(st
* tests can be used in performance sensitive paths. PageCompound is
* generally not used in hot code paths.
*/
-__PAGEFLAG(Head, head)
+__PAGEFLAG(Head, head) CLEARPAGEFLAG(Head, head)
__PAGEFLAG(Tail, tail)

static inline int PageCompound(struct page *page)
@@ -355,6 +355,13 @@ static inline int PageCompound(struct pa
return page->flags & ((1L << PG_head) | (1L << PG_tail));

}
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+static inline void ClearPageCompound(struct page *page)
+{
+ BUG_ON(!PageHead(page));
+ ClearPageHead(page);
+}
+#endif
#else
/*
* Reduce page flag use as much as possible by overlapping
@@ -392,6 +399,14 @@ static inline void __ClearPageTail(struc
page->flags &= ~PG_head_tail_mask;
}

+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+static inline void ClearPageCompound(struct page *page)
+{
+ BUG_ON(page->flags & PG_head_tail_mask != (1L << PG_compound));
+ ClearPageCompound(page);
+}
+#endif
+
#endif /* !PAGEFLAGS_EXTENDED */

#ifdef CONFIG_HAVE_MLOCKED_PAGE_BIT