Messages in this thread Patch in this message | | | Date | Fri, 26 May 2006 19:39:11 +0800 | From | Wu Fengguang <> | Subject | [PATCH 05/33] mm: introduce PG_readahead |
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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 adaptive read-ahead logic! For the sake of I/O pipelining, don't wait until it runs out of cached pages. ;-)
Signed-off-by: Wu Fengguang <wfg@mail.ustc.edu.cn> ---
include/linux/page-flags.h | 5 +++++ mm/page_alloc.c | 2 +- 2 files changed, 6 insertions(+), 1 deletion(-)
--- linux-2.6.17-rc4-mm3.orig/include/linux/page-flags.h +++ linux-2.6.17-rc4-mm3/include/linux/page-flags.h @@ -90,6 +90,8 @@ #define PG_nosave_free 18 /* Free, should not be written */ #define PG_buddy 19 /* Page is free, on buddy lists */ +#define PG_readahead 20 /* Reminder to do readahead */ + #if (BITS_PER_LONG > 32) /* @@ -372,6 +374,10 @@ extern void __mod_page_state_offset(unsi #define SetPageUncached(page) set_bit(PG_uncached, &(page)->flags) #define ClearPageUncached(page) clear_bit(PG_uncached, &(page)->flags) +#define PageReadahead(page) test_bit(PG_readahead, &(page)->flags) +#define SetPageReadahead(page) set_bit(PG_readahead, &(page)->flags) +#define TestClearPageReadahead(page) test_and_clear_bit(PG_readahead, &(page)->flags) + struct page; /* forward declaration */ int test_clear_page_dirty(struct page *page); --- linux-2.6.17-rc4-mm3.orig/mm/page_alloc.c +++ linux-2.6.17-rc4-mm3/mm/page_alloc.c @@ -564,7 +564,7 @@ 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_checked | 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/
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