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 <clameter@xxxxxxx> --- 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); } -- - To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html