From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755662AbZELPhm (ORCPT ); Tue, 12 May 2009 11:37:42 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752536AbZELPhd (ORCPT ); Tue, 12 May 2009 11:37:33 -0400 Received: from cantor2.suse.de ([195.135.220.15]:44138 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753266AbZELPhc (ORCPT ); Tue, 12 May 2009 11:37:32 -0400 Date: Tue, 12 May 2009 17:37:32 +0200 From: Nick Piggin To: Jan Beulich Cc: Ingo Molnar , Thomas Gleixner , hpa@zytor.com, linux-kernel@vger.kernel.org Subject: Re: uses of cmpxchg/xadd in spinlock.h and rwsem.h vs. CONFIG_M386 Message-ID: <20090512153732.GA31131@wotan.suse.de> References: <4A09AF8402000078000007DC@vpn.id2.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4A09AF8402000078000007DC@vpn.id2.novell.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 04:19:00PM +0100, 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? Oh, hmm, we do actually attempt to support 386 SMP kernels... I thought that config wasn't allowed, but looking at the atomic.h code, it has ifdef fallbacks. I guess some similar hacks could be added to spinlock.h code.