From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 11 Feb 2008 23:57:14 -0800 From: Andrew Morton Subject: Re: [patch 0/3] Hotcold removal completion Message-Id: <20080211235714.1484b0c7.akpm@linux-foundation.org> In-Reply-To: <200802121732.29593.nickpiggin@yahoo.com.au> References: <20080212003643.536643832@sgi.com> <200802121732.29593.nickpiggin@yahoo.com.au> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Nick Piggin Cc: Christoph Lameter , linux-mm@kvack.org, Mel Gorman List-ID: On Tue, 12 Feb 2008 17:32:29 +1100 Nick Piggin wrote: > On Tuesday 12 February 2008 11:36, Christoph Lameter wrote: > > The patch that we had in mm for the removal of the cold page queue was > > merged. > > That patch to merge the hot and cold lists has obvious problems. > It pulls cold pages off the list in the opposite order that hot > pages come off the list (which is obviously bad); and also it > allows cold allocations to deplete hot pages (which may not be a > good idea). > > Obviously the half baked code that's there now should be fixed... > But whether it is to fix hot/cold properly, or to remove it > completely, I don't really know. > Well that sounds bad. > > > However, there were 3 more pages that I think are necessary to > > complete the work. Mel's testing indicated that the patch in mm is inferior > > to simply removing the hot cold distinction in the VM altogether > > (see http://marc.info/?t=119507025400001&r=1&w=2). > > > > These 3 patches get rid of cold page handling in the VM. > > I'm all in favour of removing these. But honestly, I don't think > kernbench, [td]bench, and aim9 are really great tests when it > comes to subtle cache behaviour... OTOH, that didn't stop the > last patch being merged. May as well do it. I think I'd prefer that we convince ourselves that we didn't just merge a regression rather than merging more stuff on top of it. Because right now, page-allocator-get-rid-of-the-list-of-cold-pages.patch reverts cleanly. -- 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