From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 13 Dec 2007 21:00:57 -0700 From: Matthew Wilcox Subject: Re: [PATCH] fix page_alloc for larger I/O segments 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 Content-Disposition: inline In-Reply-To: <20071213170308.d4ce5889.akpm@linux-foundation.org> Sender: owner-linux-mm@kvack.org Return-Path: 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 List-ID: 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." -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org