From mboxrd@z Thu Jan 1 00:00:00 1970 Message-Id: <20080321061724.515504935@sgi.com> References: <20080321061703.921169367@sgi.com> Date: Thu, 20 Mar 2008 23:17:05 -0700 From: Christoph Lameter Subject: [02/14] vcompound: pageflags: Add PageVcompound() Content-Disposition: inline; filename=0004-vcompound-Pageflags-Add-PageVcompound.patch Sender: owner-linux-mm@kvack.org Return-Path: To: linux-mm@kvack.org Cc: 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 needed. We use PG_swapcache together with PG_compound (similar to PageHead() and PageTail()) to signal that a compound page is virtually mapped. PG_swapcache is not used at this point since compound pages cannot be put onto the LRU (yet). Signed-off-by: Christoph Lameter --- include/linux/page-flags.h | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) Index: linux-2.6.25-rc5-mm1/include/linux/page-flags.h =================================================================== --- linux-2.6.25-rc5-mm1.orig/include/linux/page-flags.h 2008-03-20 17:40:16.141487362 -0700 +++ linux-2.6.25-rc5-mm1/include/linux/page-flags.h 2008-03-20 17:41:58.768233703 -0700 @@ -196,6 +196,24 @@ static inline int PageHighMem(struct pag } #endif +/* + * 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 PAGEFLAG(SwapCache, swapcache) #else -- -- 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