From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261374AbTDICEU (for ); Tue, 8 Apr 2003 22:04:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261387AbTDICEU (for ); Tue, 8 Apr 2003 22:04:20 -0400 Received: from dp.samba.org ([66.70.73.150]:18073 "EHLO lists.samba.org") by vger.kernel.org with ESMTP id S261374AbTDICET (for ); Tue, 8 Apr 2003 22:04:19 -0400 From: Rusty Russell To: Alan Cox Cc: Christoph Hellwig , Paul Mackerras , Fabrice Bellard , Linux Kernel Mailing List Subject: Re: [PATCH] Qemu support for PPC In-reply-to: Your message of "07 Apr 2003 12:21:48 +0100." <1049714507.2967.29.camel@dhcp22.swansea.linux.org.uk> Date: Wed, 09 Apr 2003 12:07:24 +1000 Message-Id: <20030409021558.A186C2C013@lists.samba.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org In message <1049714507.2967.29.camel@dhcp22.swansea.linux.org.uk> you write: > > This is not qemu specific, of course. If you say it's not going in, > > then I'll accept that and do the work inside qemu. It'll be damn > > slow, of course. > > WTF should that make it slow ? Well, there are two obvious methods. The first, which I've implemented, builds a tree at start time, which assumes things stay static, but has significant startup overhead. The fully dynamic solution (which personality + emul_prefix gives you at the moment) means that you double every open, every stat, quadruple every readlink, etc. Of course, remember to handle relative paths (my current code punts on this in the hope that noone will notice: we'll see). Unfortunately, it's not just /lib and /usr/lib, there's /var/run/.nscd_socket which doesn't seem to like speaking wrong endian. Hey, I'd *love* read-only union mounts which can be done by non-root (and obviously don't survive exec), but AFAICT noone but Al can write one acceptable to the VFS maintainer 8). Rusty. -- Anyone who quotes me in their sig is an idiot. -- Rusty Russell.