From b41b9d1114ef2165cafe1a31c653fbcbd6fe7741 Mon Sep 17 00:00:00 2001 From: Christoph Lameter Date: Wed, 25 Jul 2007 20:05:38 -0700 Subject: [PATCH] compound pages: Allow use of get_page_unless_zero with compound pages This is needed by slab defragmentation. The refcount of a page head may be incremented to ensure that a compound page will not go away under us. It also may be needed for defragmentation of higher order pages. The moving of compound pages may require the establishment of a reference before the use of page migration functions. Signed-off-by: Christoph Lameter --- include/linux/mm.h | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) Index: linux-2.6/include/linux/mm.h =================================================================== --- linux-2.6.orig/include/linux/mm.h 2007-08-27 20:59:40.000000000 -0700 +++ linux-2.6/include/linux/mm.h 2007-08-27 21:03:20.000000000 -0700 @@ -290,7 +290,7 @@ static inline int put_page_testzero(stru */ static inline int get_page_unless_zero(struct page *page) { - VM_BUG_ON(PageCompound(page)); + VM_BUG_ON(PageTail(page)); return atomic_inc_not_zero(&page->_count); }