From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Fri, 14 Dec 2007 11:50:39 +0000 From: Mel Gorman Subject: Re: QUEUE_FLAG_CLUSTER: not working in 2.6.24 ? Message-ID: <20071214115038.GB11046@csn.ul.ie> References: <476190BE.9010405@rtr.ca> <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> <20071213163726.3bb601fa.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20071213163726.3bb601fa.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, matthew@wil.cx, linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org, linux-mm@kvack.org List-ID: On (13/12/07 16:37), Andrew Morton didst pronounce: > On Thu, 13 Dec 2007 19:30:00 -0500 > Mark Lord wrote: > > > Here's the commit that causes the regression: > > > > ... > > > > --- a/mm/page_alloc.c > > +++ b/mm/page_alloc.c > > @@ -760,7 +760,8 @@ static int rmqueue_bulk(struct zone *zone, unsigned int order, > > struct page *page = __rmqueue(zone, order, migratetype); > > if (unlikely(page == NULL)) > > break; > > - list_add_tail(&page->lru, list); > > + list_add(&page->lru, list); > > well that looks fishy. > The reasoning behind the change was the first page encountered on the list by the caller would have a matching migratetype. I failed to take into account the physical ordering of pages returned. I'm setting up to run some performance benchmarks of the candidate fix merged into the -mm tree to see if the search shows up or not. I'm testing against 2.6.25-rc5 but it'll take a few hours to complete. -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab -- 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