From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030779AbXCTAHt (ORCPT ); Mon, 19 Mar 2007 20:07:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030780AbXCTAHt (ORCPT ); Mon, 19 Mar 2007 20:07:49 -0400 Received: from smtp.osdl.org ([65.172.181.24]:35653 "EHLO smtp.osdl.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030779AbXCTAHs (ORCPT ); Mon, 19 Mar 2007 20:07:48 -0400 Date: Mon, 19 Mar 2007 17:07:41 -0700 From: Andrew Morton To: Christoph Lameter Cc: linux-mm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [QUICKLIST 1/5] Quicklists for page table pages V3 Message-Id: <20070319170741.5a24af4c.akpm@linux-foundation.org> In-Reply-To: References: <20070319233716.13775.45569.sendpatchset@schroedinger.engr.sgi.com> <20070319165329.b5830789.akpm@linux-foundation.org> X-Mailer: Sylpheed version 2.2.7 (GTK+ 2.8.6; i686-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 X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 19 Mar 2007 16:57:55 -0700 (PDT) Christoph Lameter wrote: > On Mon, 19 Mar 2007, Andrew Morton wrote: > > > Has it been proven that quicklists are superior to simply going direct to the > > page allocator for these pages? > > Yes. Sigh. Please provide proof that quicklists are superior to simply going direct to the page allocator for these pages. > > Would it provide a superior solution if we were to a) stop zeroing out the > > pte's when doing a fullmm==1 teardown and b) go direct to the page allocator > > for these pages? > > I doubt it. The zeroing is a by product of our way of serializing pte > handling. Its going to be difficult to change that. Nick didn't think so, and I don't see the problem either. We'll save on some bus traffic by avoiding the writeback, but how much effect that will have we don't know. Presumably little.