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From: Andrew Morton <akpm@linux-foundation.org>
To: Fengguang Wu <wfg@mail.ustc.edu.cn>
Cc: linux-kernel@vger.kernel.org, Andi Kleen <andi@firstfloor.org>,
	Jens Axboe <jens.axboe@oracle.com>,
	Oleg Nesterov <oleg@tv-sign.ru>,
	Steven Pratt <slpratt@austin.ibm.com>,
	Ram Pai <linuxram@us.ibm.com>
Subject: Re: [PATCH 1/9] readahead: introduce PG_readahead
Date: Fri, 18 May 2007 23:28:24 -0700	[thread overview]
Message-ID: <20070518232824.9917d794.akpm@linux-foundation.org> (raw)
In-Reply-To: <379355695.83536@ustc.edu.cn>

On Thu, 17 May 2007 06:47:53 +0800 Fengguang Wu <wfg@mail.ustc.edu.cn> wrote:

> Introduce a new page flag: PG_readahead.

Is there any way in which we can avoid adding a new page flag?

We have the advantage that if the kernel very occasionally gets the wrong
result for PageReadahead(page), nothing particularly bad will happen, so we
can do racy things.

>From a quick peek, it appears that PG_readahead is only ever set against
non-uptodate pages.  If true we could perhaps exploit that: say,
PageReadahead(page) == PG_referenced && !PG_uptodate?

  reply	other threads:[~2007-05-19  6:33 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-05-16 22:47 [PATCH 0/9] on-demand readahead Fengguang Wu
2007-05-16 22:47 ` Fengguang Wu
2007-05-16 22:47 ` [PATCH 1/9] readahead: introduce PG_readahead Fengguang Wu
2007-05-16 22:47   ` Fengguang Wu
2007-05-19  6:28     ` Andrew Morton [this message]
2007-05-19 11:35       ` Andi Kleen
2007-05-19 15:19         ` Andrew Morton
2007-05-19 12:30       ` Fengguang Wu
2007-05-19 12:30         ` Fengguang Wu
2007-05-19 15:25           ` Andrew Morton
2007-05-20  3:09             ` Fengguang Wu
2007-05-20  3:09               ` Fengguang Wu
2007-05-20  7:10                 ` Christoph Lameter
2007-06-12  1:04   ` Rusty Russell
2007-06-12  2:52     ` Fengguang Wu
2007-06-12  2:52       ` Fengguang Wu
2007-05-16 22:47 ` [PATCH 2/9] readahead: add look-ahead support to __do_page_cache_readahead() Fengguang Wu
2007-05-16 22:47   ` Fengguang Wu
2007-05-16 22:47 ` [PATCH 3/9] readahead: MIN_RA_PAGES/MAX_RA_PAGES macros Fengguang Wu
2007-05-16 22:47   ` Fengguang Wu
2007-05-16 22:47 ` [PATCH 4/9] readahead: data structure and routines Fengguang Wu
2007-05-16 22:47   ` Fengguang Wu
2007-06-12  3:30   ` Rusty Russell
2007-06-12 12:07     ` Fengguang Wu
2007-06-12 12:07       ` Fengguang Wu
2007-06-13  0:27       ` Rusty Russell
2007-06-13  3:07         ` Fengguang Wu
2007-06-13  3:07           ` Fengguang Wu
2007-05-16 22:47 ` [PATCH 5/9] readahead: on-demand readahead logic Fengguang Wu
2007-05-16 22:47   ` Fengguang Wu
2007-05-19  6:23     ` Andrew Morton
2007-05-19 13:02       ` Fengguang Wu
2007-05-19 13:02         ` Fengguang Wu
2007-06-12  4:36   ` Rusty Russell
2007-06-12 10:35     ` Fengguang Wu
2007-06-12 10:35       ` Fengguang Wu
2007-06-13  1:40       ` Rusty Russell
2007-06-13  4:00         ` Fengguang Wu
2007-06-13  4:00           ` Fengguang Wu
2007-06-13  5:51           ` Rusty Russell
2007-06-13  7:07             ` Fengguang Wu
2007-06-13  7:07               ` Fengguang Wu
2007-05-16 22:47 ` [PATCH 6/9] readahead: convert filemap invocations Fengguang Wu
2007-05-16 22:47   ` Fengguang Wu
2007-05-16 22:47 ` [PATCH 7/9] readahead: convert splice invocations Fengguang Wu
2007-05-16 22:47   ` Fengguang Wu
2007-05-16 22:48 ` [PATCH 8/9] readahead: convert ext3/ext4 invocations Fengguang Wu
2007-05-16 22:48   ` Fengguang Wu
2007-05-19 12:19   ` Andi Kleen
2007-05-16 22:48 ` [PATCH 9/9] readahead: remove the old algorithm Fengguang Wu
2007-05-16 22:48   ` Fengguang Wu
2007-05-19 12:18   ` Andi Kleen
2007-05-19 13:17     ` Fengguang Wu
2007-05-19 13:17       ` Fengguang Wu

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