Introduce a new page flag: PG_readahead. It acts as a look-ahead mark, which tells the page reader: Hey, it's time to invoke the read-ahead logic. For the sake of I/O pipelining, don't wait until it runs out of cached pages! Signed-off-by: Fengguang Wu --- include/linux/page-flags.h | 5 +++++ mm/page_alloc.c | 2 +- 2 files changed, 6 insertions(+), 1 deletion(-) --- linux-2.6.22-rc1-mm1.orig/include/linux/page-flags.h +++ linux-2.6.22-rc1-mm1/include/linux/page-flags.h @@ -92,6 +92,7 @@ #define PG_lazyfree 20 /* MADV_FREE potential throwaway */ #define PG_booked 21 /* Has blocks reserved on-disk */ +#define PG_readahead 22 /* Reminder to do async read-ahead */ /* PG_owner_priv_1 users should have descriptive aliases */ #define PG_checked PG_owner_priv_1 /* Used by some filesystems */ @@ -206,6 +207,10 @@ static inline void SetPageUptodate(struc #define SetPageBooked(page) set_bit(PG_booked, &(page)->flags) #define ClearPageBooked(page) clear_bit(PG_booked, &(page)->flags) +#define PageReadahead(page) test_bit(PG_readahead, &(page)->flags) +#define SetPageReadahead(page) set_bit(PG_readahead, &(page)->flags) +#define ClearPageReadahead(page) clear_bit(PG_readahead, &(page)->flags) + #define PageReclaim(page) test_bit(PG_reclaim, &(page)->flags) #define SetPageReclaim(page) set_bit(PG_reclaim, &(page)->flags) #define ClearPageReclaim(page) clear_bit(PG_reclaim, &(page)->flags) --- linux-2.6.22-rc1-mm1.orig/mm/page_alloc.c +++ linux-2.6.22-rc1-mm1/mm/page_alloc.c @@ -659,7 +659,7 @@ static int prep_new_page(struct page *pa if (PageReserved(page)) return 1; - page->flags &= ~(1 << PG_uptodate | 1 << PG_error | + page->flags &= ~(1 << PG_uptodate | 1 << PG_error | 1 << PG_readahead | 1 << PG_referenced | 1 << PG_arch_1 | 1 << PG_owner_priv_1 | 1 << PG_mappedtodisk); set_page_private(page, 0); -- - 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/