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 from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/