From: Andrew Morton <akpm@linux-foundation.org>
To: Andi Kleen <andi@firstfloor.org>
Cc: Fengguang Wu <wfg@mail.ustc.edu.cn>,
linux-kernel@vger.kernel.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: Sat, 19 May 2007 08:19:44 -0700 [thread overview]
Message-ID: <20070519081944.3caf4776.akpm@linux-foundation.org> (raw)
In-Reply-To: <20070519113501.GB25563@one.firstfloor.org>
On Sat, 19 May 2007 13:35:01 +0200 Andi Kleen <andi@firstfloor.org> wrote:
> > 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.
>
> On 64bit there is no particular shortage of page flags.
I think pretty much all of the upper 32 bits got used for ia64 fields,
but it's never been very clear how many were actually used or needed.
> If you ever do racy things please do them 32bit only.
hrm. It *really* won't matter if we make one suboptimal readahead decision
every second day. And there's value in having the same behaviour on all
architectures.
next prev parent reply other threads:[~2007-05-19 15:25 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
2007-05-19 11:35 ` Andi Kleen
2007-05-19 15:19 ` Andrew Morton [this message]
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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