From: Mel Gorman The statistics patch later needs to know what order a free page is on the free lists. Rather than having special knowledge of page_private() when PageBuddy() is set, this patch places out page_order() in internal.h and adds a VM_BUG_ON to catch using it on non-PageBuddy pages. Signed-off-by: Mel Gorman Signed-off-by: Christoph Lameter Acked-by: Andy Whitcroft Signed-off-by: Andrew Morton --- mm/internal.h | 10 ++++++++++ mm/page_alloc.c | 10 ---------- 2 files changed, 10 insertions(+), 10 deletions(-) diff -puN mm/internal.h~breakout-page_order-to-internalh-to-avoid-special-knowledge-of-the-buddy-allocator mm/internal.h --- a/mm/internal.h~breakout-page_order-to-internalh-to-avoid-special-knowledge-of-the-buddy-allocator +++ a/mm/internal.h @@ -37,4 +37,14 @@ static inline void __put_page(struct pag extern void fastcall __init __free_pages_bootmem(struct page *page, unsigned int order); +/* + * function for dealing with page's order in buddy system. + * zone->lock is already acquired when we use these. + * So, we don't need atomic page->flags operations here. + */ +static inline unsigned long page_order(struct page *page) +{ + VM_BUG_ON(!PageBuddy(page)); + return page_private(page); +} #endif diff -puN mm/page_alloc.c~breakout-page_order-to-internalh-to-avoid-special-knowledge-of-the-buddy-allocator mm/page_alloc.c --- a/mm/page_alloc.c~breakout-page_order-to-internalh-to-avoid-special-knowledge-of-the-buddy-allocator +++ a/mm/page_alloc.c @@ -312,16 +312,6 @@ static inline void prep_zero_page(struct clear_highpage(page + i); } -/* - * function for dealing with page's order in buddy system. - * zone->lock is already acquired when we use these. - * So, we don't need atomic page->flags operations here. - */ -static inline unsigned long page_order(struct page *page) -{ - return page_private(page); -} - static inline void set_page_order(struct page *page, int order) { set_page_private(page, order); _