Messages in this thread Patch in this message | | | Date | Wed, 24 May 2006 20:37:40 +0800 | From | Wu Fengguang <> | Subject | Re: [PATCH 04/33] readahead: page flag PG_readahead |
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On Wed, May 24, 2006 at 02:27:36PM +0200, Peter Zijlstra wrote: > On Wed, 2006-05-24 at 19:12 +0800, Wu Fengguang wrote: > > plain text document attachment > > (readahead-page-flag-PG_readahead.patch) > > 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-2.6.17-rc4-mm3.orig/include/linux/page-flags.h > > +++ linux-2.6.17-rc4-mm3/include/linux/page-flags.h > > @@ -89,6 +89,7 @@ > > #define PG_reclaim 17 /* To be reclaimed asap */ > > #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 */ > > > > Page flags are gouped by four, 20 would start a new set. > Also in my tree (git from a few days ago), 20 is taken by PG_unchached.
Thanks, grouped and renumbered it as 21.
> What code is this patch-set against?
It's against the latest -mm tree: linux-2.6.17-rc4-mm3.
Wu ---
Subject: readahead: page flag PG_readahead
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-2.6.17-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 21 /* 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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