From: Andrew Morton <akpm@linux-foundation.org>
To: Andi Kleen <andi@firstfloor.org>
Cc: Jan Kara <jack@suse.cz>,
linux-kernel@vger.kernel.org, npiggin@suse.de,
WU Fengguang <wfg@mail.ustc.edu.cn>
Subject: Re: [PATCH] Improve heuristic detecting sequential reads
Date: Tue, 10 Apr 2007 16:45:40 -0700 [thread overview]
Message-ID: <20070410164540.6d10ddd7.akpm@linux-foundation.org> (raw)
In-Reply-To: <p73y7kzj0ss.fsf@bingen.suse.de>
On 11 Apr 2007 00:56:51 +0200
Andi Kleen <andi@firstfloor.org> wrote:
> Jan Kara <jack@suse.cz> writes:
>
> > Hello!
> >
> > In thread http://lkml.org/lkml/2007/3/9/403, we discussed a problem
> > with the current heuristic for detecting sequential IO in
> > do_generic_mapping_read() - for small files a page is marked as accessed
> > only once which can cause a performance problems.
> > Attached is a patch that improves the heuristic by introducing a
> > ra.offset variable so now we can reliably detect sequetial reads.
> > The patch replaces Nick's patch from http://lkml.org/lkml/2007/3/15/177
> > (Nick has acked to replace the patch). Could you please put the patch
> > into -mm?
>
> There's a much more complete patchkit for this that gets reposted
> regularly on l-k. Perhaps it would make sense to test that first?
adaptive readahead? Has been in -mm for a year. Problem is, it is
_so_ complete that I just don't know how to merge it. It's huge, and
only Wu understands it. So it's really rather stuck.
next prev parent reply other threads:[~2007-04-10 23:46 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-04-10 15:54 [PATCH] Improve heuristic detecting sequential reads Jan Kara
2007-04-10 22:56 ` Andi Kleen
2007-04-10 23:45 ` Andrew Morton [this message]
2007-04-11 3:54 ` WU Fengguang
2007-04-11 3:54 ` WU Fengguang
2007-04-11 10:20 ` Andi Kleen
2007-04-11 2:27 ` Andrew Morton
2007-04-11 12:17 ` Jan Kara
2007-04-12 15:57 ` Jan Kara
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