From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755580AbYATFPG (ORCPT ); Sun, 20 Jan 2008 00:15:06 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751322AbYATFO4 (ORCPT ); Sun, 20 Jan 2008 00:14:56 -0500 Received: from one.firstfloor.org ([213.235.205.2]:58149 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750856AbYATFOz (ORCPT ); Sun, 20 Jan 2008 00:14:55 -0500 Date: Sun, 20 Jan 2008 06:18:22 +0100 From: Andi Kleen To: David Newall Cc: Andi Kleen , akpm@osdl.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH for mm] Remove iBCS support Message-ID: <20080120051822.GB19784@one.firstfloor.org> References: <20080119045918.GA12215@basil.nowhere.org> <4792B191.2060801@davidnewall.com> <20080120031153.GB6275@one.firstfloor.org> <4792D221.1010704@davidnewall.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4792D221.1010704@davidnewall.com> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Jan 20, 2008 at 03:16:25PM +1030, David Newall wrote: > Andi Kleen wrote: > > On Sun, Jan 20, 2008 at 12:57:29PM +1030, David Newall wrote: > > > >> compatibility. This is a sleeping giant for Linux. There are plenty of > >> > > > > Interesting choice of words. > > > KFC and Dominoes use SCO for their cash registers, to pick just two > enormous future opportunities. I suppose if they update their cash registers they will just go with fully Linux binaries. > > But it does not make sense for all Linux kernels to always check for iBCS executables > > when they don't have to code to run them anyways. > > > > I don't suppose you're suggesting this will make a big difference. Even > if every exec did nothing but immediately exit, it still wouldn't make > much difference. It's not a big difference, but why do unnecessary work on all Linux kernels? There are a lot of Linux machines out there and if all of them only do a little unnecessary work each fork() over a year it adds up to really a lot of wasted cycles. Especially since the few people who might really need it can easily readd it. > Likewise, I take your point about proper iBCS support (and I suppose > it's really iBCS2 that we're talking about.) My concern is that > removing this now gains almost nothing, 2 strcmp per exec is as close to > nothing as anything, but it sends a message with which I disagree. The > message should be that Linux is good for, well the same things FreeBSD > is, and includes running Solaris and SCO binaries. This is a major But Linux is not good for this currently, at least not unless you add a significant patch (which I'm not sure does even exist for modern 2.6; iBCS was mainly deployed on 2.4 kernels). And when you add that patch you can easily readd the strcmps too. > simplification of the story, I know, but still hits the plot highlights. You're worried about this patch generating headlines? -Andi