From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Wilcox Subject: Re: [PATCH] fix page_alloc for larger I/O segments Date: Thu, 13 Dec 2007 21:00:57 -0700 Message-ID: <20071214040056.GS26334@parisc-linux.org> References: <20071213200958.GK10104@kernel.dk> <20071213140207.111f94e2.akpm@linux-foundation.org> <1197584106.3154.55.camel@localhost.localdomain> <20071213142935.47ff19d9.akpm@linux-foundation.org> <4761B32A.3070201@rtr.ca> <4761BCB4.1060601@rtr.ca> <4761C8E4.2010900@rtr.ca> <4761CE88.9070406@rtr.ca> <4761D0E9.4010701@rtr.ca> <20071213170308.d4ce5889.akpm@linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from palinux.external.hp.com ([192.25.206.14]:41875 "EHLO mail.parisc-linux.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750724AbXLNEA6 (ORCPT ); Thu, 13 Dec 2007 23:00:58 -0500 Content-Disposition: inline In-Reply-To: <20071213170308.d4ce5889.akpm@linux-foundation.org> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Andrew Morton Cc: Mark Lord , James.Bottomley@HansenPartnership.com, jens.axboe@oracle.com, lkml@rtr.ca, linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org, linux-mm@kvack.org, mel@csn.ul.ie On Thu, Dec 13, 2007 at 05:03:08PM -0800, Andrew Morton wrote: > + /* > + * Find a page of the appropriate migrate type. Doing a > + * reverse-order search here helps us to hand out pages in > + * ascending physical-address order. > + */ > + list_for_each_entry_reverse(page, &pcp->list, lru) It's not obvious why ascending physical order is a good thing. How about: + /* + * Find a page of the appropriate migrate type. Doing a + * reverse-order search here helps us to hand out pages in + * ascending physical-address order, which improves our + * chances of coalescing scatter-gather pages. + */ -- Intel are signing my paycheques ... these opinions are still mine "Bill, look, we understand that you're interested in selling us this operating system, but compare it to ours. We can't possibly take such a retrograde step."