From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753659AbXCPUtF (ORCPT ); Fri, 16 Mar 2007 16:49:05 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753656AbXCPUtF (ORCPT ); Fri, 16 Mar 2007 16:49:05 -0400 Received: from netops-testserver-3-out.sgi.com ([192.48.171.28]:39617 "EHLO netops-testserver-3.corp.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753659AbXCPUtC (ORCPT ); Fri, 16 Mar 2007 16:49:02 -0400 Date: Fri, 16 Mar 2007 13:48:58 -0700 (PDT) From: Christoph Lameter X-X-Sender: clameter@schroedinger.engr.sgi.com To: Martin Bligh cc: Andi Kleen , Steven Rostedt , Linus Torvalds , Ingo Molnar , linux-kernel@vger.kernel.org, Andrew Morton , Chris Wright , Rusty Russell , Glauber de Oliveira Costa , Andy Whitcroft Subject: Re: [PATCH 00/18] Make common x86 arch area for i386 and x86_64 - Take 2 In-Reply-To: <45FAFD57.90601@mbligh.org> Message-ID: References: <20070314050819.536207642@goodmis.org> <20070314125330.GA13168@elte.hu> <45F96B57.10206@mbligh.org> <20070315160648.GA11812@one.firstfloor.org> <1173977264.7922.24.camel@localhost.localdomain> <20070316114415.GA26403@one.firstfloor.org> <45FAFD57.90601@mbligh.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 16 Mar 2007, Martin Bligh wrote: > You have to do some sort of lookup anyway, and Andy seemed to have them > all folded into one. What lookup would you need to do? On x86_64 even the TLB use is hidden by the existing 2M entries for 1-1 mappings. > Or are you trying to avoid this by going to back to the crud we had > in 2.4 where we pretend mem_map is one big array, indexed by pfn with > huge sparsely mapped holes in it? Yes that the advanced way of doing it rather than adding useless custom lookups. > Would be nice to work out (and document somewhere) what the pros and > cons of virtual memmap vs sparsemem were - ISTR one of the arguments > was extremely sparsely layed out machines, and you needed sparsemem > for that. But right now we have 3 solutions, which is not a good > situation. Please read my posts to linux-mm on that subject. We discussed it last year in detail and the agreement was that the sparsemem crud needs to be taken out. Kame-san posted patches to do that.