Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755839Ab2KMUga (ORCPT ); Tue, 13 Nov 2012 15:36:30 -0500 Received: from mail-ea0-f174.google.com ([209.85.215.174]:54616 "EHLO mail-ea0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755695Ab2KMUg2 (ORCPT ); Tue, 13 Nov 2012 15:36:28 -0500 MIME-Version: 1.0 In-Reply-To: <50A2A706.1090608@zytor.com> References: <20121112193044.GA11615@phenom.dumpdata.com> <1352755122-25660-1-git-send-email-yinghai@kernel.org> <1352755122-25660-22-git-send-email-yinghai@kernel.org> <50A2A706.1090608@zytor.com> Date: Tue, 13 Nov 2012 12:36:27 -0800 X-Google-Sender-Auth: 6Nm6nd6jKgHEeDhDg0l8EumqWYo Message-ID: Subject: Re: [PATCH 21/46] x86, mm: setup page table in top-down From: Yinghai Lu To: "H. Peter Anvin" Cc: Stefano Stabellini , Thomas Gleixner , Ingo Molnar , Jacob Shin , Andrew Morton , Konrad Rzeszutek Wilk , "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1509 Lines: 43 On Tue, Nov 13, 2012 at 12:01 PM, H. Peter Anvin wrote: > On 11/13/2012 11:59 AM, Yinghai Lu wrote: >>> >>> The changes to init_mem_mapping are a bit iffy but they aren't too >>> unreasonable. >>> Overall the patch is OK even though I would certainly appreciate more >>> comments and better variable names (real_end?), see below. >> >> real_end is not good? >> >> xen put big reserved range between real_end and end. >> >> that real_end is some kind of end of real usable areas. >> >> so change to real_usable_end or usable_end? >> > > A description of a variable that includes the words "some kind of" > clearly indicates major confusion. We need to know what the semantics > are, here. originally, we map range in this sequence: 1. map [0, 1M], 2. map 2M near max_pfn. and end is max_pfn<