From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 20141 invoked by alias); 26 Jun 2007 17:55:02 -0000 Received: (qmail 20130 invoked by uid 22791); 26 Jun 2007 17:55:02 -0000 X-Spam-Check-By: sourceware.org Received: from mail.codesourcery.com (HELO mail.codesourcery.com) (65.74.133.4) by sourceware.org (qpsmtpd/0.31) with ESMTP; Tue, 26 Jun 2007 17:54:59 +0000 Received: (qmail 29801 invoked from network); 26 Jun 2007 17:54:56 -0000 Received: from unknown (HELO localhost) (jimb@127.0.0.2) by mail.codesourcery.com with ESMTPA; 26 Jun 2007 17:54:56 -0000 To: Michael Eager Cc: gdb@sources.redhat.com Subject: Re: Non-uniform address spaces References: <467D4AE3.7020505@eagercon.com> <20070623212557.GB3448@caradoc.them.org> <467D9503.9060804@eagercon.com> <46800482.4020700@eagercon.com> <46801FDD.4020408@eagercon.com> <468047F0.7060207@eagercon.com> <46814B4C.7080302@eagercon.com> From: Jim Blandy Date: Tue, 26 Jun 2007 17:55:00 -0000 In-Reply-To: <46814B4C.7080302@eagercon.com> (Michael Eager's message of "Tue, 26 Jun 2007 10:22:20 -0700") Message-ID: User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.0.50 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-IsSubscribed: yes Mailing-List: contact gdb-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-owner@sourceware.org X-SW-Source: 2007-06/txt/msg00307.txt.bz2 Michael Eager writes: >>> One problem may be that it may not be clear whether one has a >>> pointer to a linear code space or to a distributed NUMA data space. >>> It might be reasonable to model the linear code space as a 64-bit >>> CORE_ADDR, with the top half zero, while a NUMA address has non-zero >>> values in the top half. (I don't know if there might be alias >>> problems, where zero might be valid for the top half of a NUMA address.) >> >> I think this isn't going to be a problem, but it's hard to tell. Can >> you think of a specific case where we wouldn't be able to tell which >> we have? > > Only if the component of a NUMA address can be > zero, and looks like a linear address. I guess what I've been getting at is, why do we need to represent both NUMA and linear addresses? If linear addresses refer to specific subsets of the grand unified NUMA address space, then we should simply declare CORE_ADDR to hold NUMA addresses, and make sure that linear addresses always get converted to NUMA addresses at a point where we have enough context to do so.