Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932729AbWEXMho (ORCPT ); Wed, 24 May 2006 08:37:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932731AbWEXMho (ORCPT ); Wed, 24 May 2006 08:37:44 -0400 Received: from smtp.ustc.edu.cn ([202.38.64.16]:36265 "HELO ustc.edu.cn") by vger.kernel.org with SMTP id S932729AbWEXMhn (ORCPT ); Wed, 24 May 2006 08:37:43 -0400 Message-ID: <348474258.29290@ustc.edu.cn> X-EYOUMAIL-SMTPAUTH: wfg@mail.ustc.edu.cn Date: Wed, 24 May 2006 20:37:40 +0800 From: Wu Fengguang To: Peter Zijlstra Cc: Andrew Morton , linux-kernel@vger.kernel.org Subject: Re: [PATCH 04/33] readahead: page flag PG_readahead Message-ID: <20060524123740.GA16304@mail.ustc.edu.cn> Mail-Followup-To: Wu Fengguang , Peter Zijlstra , Andrew Morton , linux-kernel@vger.kernel.org References: <20060524111246.420010595@localhost.localdomain> <20060524111858.869793445@localhost.localdomain> <1148473656.10561.46.camel@lappy> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1148473656.10561.46.camel@lappy> User-Agent: Mutt/1.5.11+cvs20060126 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3402 Lines: 90 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 > > --- > > > > 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 --- 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/