From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757136AbZBJXNT (ORCPT ); Tue, 10 Feb 2009 18:13:19 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756148AbZBJXNL (ORCPT ); Tue, 10 Feb 2009 18:13:11 -0500 Received: from smtp1.linux-foundation.org ([140.211.169.13]:36358 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756101AbZBJXNK (ORCPT ); Tue, 10 Feb 2009 18:13:10 -0500 Date: Tue, 10 Feb 2009 15:12:47 -0800 From: Andrew Morton To: MinChan Kim Cc: kosaki.motohiro@jp.fujitsu.com, kamezawa.hiroyu@jp.fujitsu.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, riel@redhat.com Subject: Re: [PATCH] mm: remove zone->prev_prioriy Message-Id: <20090210151247.6747f66e.akpm@linux-foundation.org> In-Reply-To: <28c262360902100257o6a8e2374v42f1ae906c53bcec@mail.gmail.com> References: <20090210184055.6FCB.KOSAKI.MOTOHIRO@jp.fujitsu.com> <28c262360902100257o6a8e2374v42f1ae906c53bcec@mail.gmail.com> X-Mailer: Sylpheed version 2.2.4 (GTK+ 2.8.20; i486-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 10 Feb 2009 19:57:01 +0900 MinChan Kim wrote: > As you know, prev_priority is used as a measure of how much stress page reclaim. > But now we doesn't need it due to split-lru's way. > > I think it would be better to remain why prev_priority isn't needed any more > and how split-lru can replace prev_priority's role in changelog. > > In future, it help mm newbies understand change history, I think. Yes, I'd be fascinated to see that explanation. In http://groups.google.pn/group/linux.kernel/browse_thread/thread/fea9c9a0b43162a1 it was asserted that we intend to use prev_priority again in the future. We discussed this back in November: http://lkml.indiana.edu/hypermail/linux/kernel/0811.2/index.html#00001 And I think that I still think that the VM got worse due to its (new) failure to track previous state. IIRC, the response to that concern was quite similar to handwavy waffling.