Messages in this thread Patch in this message | | | Date | Sun, 19 Mar 2006 10:34:17 +0800 | From | Wu Fengguang <> | Subject | [PATCH 04/23] readahead: page flag PG_readahead |
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An new page flag PG_readahead is introduced as a look-ahead mark, which reminds the caller to give the adaptive read-ahead logic a chance to do read-ahead ahead of time for I/O pipelining.
It roughly corresponds to `ahead_start' of the stock read-ahead logic.
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-2.6.16-rc6-mm2.orig/include/linux/page-flags.h +++ linux-2.6.16-rc6-mm2/include/linux/page-flags.h @@ -76,6 +76,7 @@ #define PG_reclaim 17 /* To be reclaimed asap */ #define PG_nosave_free 18 /* Free, should not be written */ #define PG_uncached 19 /* Page has been mapped as uncached */ +#define PG_readahead 20 /* Reminder to do readahead */ /* * Global page accounting. One instance per CPU. Only unsigned longs are @@ -343,6 +344,10 @@ 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-2.6.16-rc6-mm2.orig/mm/page_alloc.c +++ linux-2.6.16-rc6-mm2/mm/page_alloc.c @@ -549,7 +549,7 @@ 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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