From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759602AbZELP5o (ORCPT ); Tue, 12 May 2009 11:57:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756250AbZELP5F (ORCPT ); Tue, 12 May 2009 11:57:05 -0400 Received: from cantor.suse.de ([195.135.220.2]:45808 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756381AbZELP5E (ORCPT ); Tue, 12 May 2009 11:57:04 -0400 Date: Tue, 12 May 2009 17:57:02 +0200 From: Nick Piggin To: "H. Peter Anvin" Cc: Jan Beulich , Ingo Molnar , Thomas Gleixner , linux-kernel@vger.kernel.org Subject: Re: uses of cmpxchg/xadd in spinlock.h and rwsem.h vs. CONFIG_M386 Message-ID: <20090512155702.GB31131@wotan.suse.de> References: <4A09AF8402000078000007DC@vpn.id2.novell.com> <4A099AF0.8020001@zytor.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4A099AF0.8020001@zytor.com> User-Agent: Mutt/1.5.9i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, May 12, 2009 at 08:51:12AM -0700, H. Peter Anvin wrote: > Jan Beulich wrote: > > While looking at a completely different issue I happened to grep for uses of > > xadd, and it would appear to me that there got uses added that would make > > a M386-configured SMP kernel die on an actual i386. > > > > Oh, for the rwsem case I see - it would use the RWSEM_GENERIC_SPINLOCK case > > when selecting M386. But I see nothing similar for the ticket spinlocks - am > > I overlooking something? > > It's quite possible we break 386 on a regular basis... I'm not sure how > many people even in the embedded industry run current kernels on > 386-compatible hardware. Most embedded hardware is at least 486. Is it time to get rid of attempts to support SMP kernels that run on 386, then? Considering we don't actually support SMP 386, and if there is any 386 systems then they're going to be running custom kernels anyway.