From mboxrd@z Thu Jan  1 00:00:00 1970
From: Mark Lord <lkml@rtr.ca>
Subject: Re: QUEUE_FLAG_CLUSTER: not working in 2.6.24 ?
Date: Thu, 13 Dec 2007 14:03:59 -0500
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To: Matthew Wilcox <matthew@wil.cx>
Cc: Jens Axboe <axboe@kernel.dk>, IDE/ATA development list <linux-ide@vger.kernel.org>, Linux Kernel <linux-kernel@vger.kernel.org>, linux-scsi <linux-scsi@vger.kernel.org>

Matthew Wilcox wrote:
> On Thu, Dec 13, 2007 at 01:48:18PM -0500, Mark Lord wrote:
>> Problem confirmed.  2.6.23.8 regularly generates segments up to 64KB for 
>> libata,
>> but 2.6.24 uses only 4KB segments and a *few* 8KB segments.
> 
> Just a suspicion ... could this be slab vs slub?  ie check your configs
> are the same / similar between the two kernels.
..

Mmmm.. a good thought, that one.
But I just rechecked, and both have CONFIG_SLAB=y

My guess is that something got changed around when Jens
reworked the block layer for 2.6.24.
I'm going to dig around in there now.