lkml.org 
[lkml]   [2006]   [Mar]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH 04/23] 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-2.6.16-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/

\
 
 \ /
  Last update: 2006-03-19 03:47    [W:0.136 / U:0.172 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site