From mboxrd@z Thu Jan 1 00:00:00 1970 Message-Id: <20071004040002.849512773@sgi.com> References: <20071004035935.042951211@sgi.com> Date: Wed, 03 Oct 2007 20:59:40 -0700 From: Christoph Lameter Subject: [05/18] Page flags: Add PageVcompound() Content-Disposition: inline; filename=vcompound_pagevcompound Sender: owner-linux-mm@kvack.org Return-Path: To: akpm@linux-foundation.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org List-ID: Add a another page flag that can be used to figure out if a compound page is virtually mapped. The mark is necessary since we have to know when freeing pages if we have to destroy a virtual mapping. No additional flag is consumed through the use of PG_swapcache together with PG_compound (similar to PageHead() and PageTail()). Signed-off-by: Christoph Lameter --- include/linux/page-flags.h | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) Index: linux-2.6/include/linux/page-flags.h =================================================================== --- linux-2.6.orig/include/linux/page-flags.h 2007-10-03 19:31:51.000000000 -0700 +++ linux-2.6/include/linux/page-flags.h 2007-10-03 19:34:37.000000000 -0700 @@ -248,6 +248,24 @@ static inline void __ClearPageTail(struc #define __SetPageHead(page) __SetPageCompound(page) #define __ClearPageHead(page) __ClearPageCompound(page) +/* + * PG_swapcache is used in combination with PG_compound to indicate + * that a compound page was allocated via vmalloc. + */ +#define PG_vcompound_mask ((1L << PG_compound) | (1L << PG_swapcache)) +#define PageVcompound(page) ((page->flags & PG_vcompound_mask) \ + == PG_vcompound_mask) + +static inline void __SetPageVcompound(struct page *page) +{ + page->flags |= PG_vcompound_mask; +} + +static inline void __ClearPageVcompound(struct page *page) +{ + page->flags &= ~PG_vcompound_mask; +} + #ifdef CONFIG_SWAP #define PageSwapCache(page) test_bit(PG_swapcache, &(page)->flags) #define SetPageSwapCache(page) set_bit(PG_swapcache, &(page)->flags) -- -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org