From: Andi Kleen Subject: Re: [patch 2/8] Implement always-locked bit ops, for memory shared with an SMP hypervisor. Date: Thu, 3 Aug 2006 08:02:44 +0200 Message-ID: <200608030802.44391.ak@suse.de> References: <20060803002510.634721860@xensource.com> <200608030739.13334.ak@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org To: Christoph Lameter Cc: virtualization@lists.osdl.org, Jeremy Fitzhardinge , akpm@osdl.org, xen-devel@lists.xensource.com, Chris Wright , Ian Pratt , linux-kernel@vger.kernel.org List-Id: xen-devel@lists.xenproject.org On Thursday 03 August 2006 07:54, Christoph Lameter wrote: > On Thu, 3 Aug 2006, Andi Kleen wrote: > > > > I still wonder why you are so focused on ifdefs. Why would we need those? > > > > Because the Xen drivers will run on a couple of architectures, including > > IA64 and PPC. > > > > If IA64 or PPC didn't implement at least wrappers for the sync ops > > then they would all need special ifdefs to handle this. > > No they would just need to do an #include If IA64 and PPC64 wouldn't have xen-bitops.h (which you seem to argue for) then they would need ifdefs. > > But you would still need to add that to IA64, PPC etc. too, so it > > would only avoid adding a single to the other architectures. > > Could we not just add one fallback definition to asm-generic? You mean into asm-generic/bitops.h? Then it would need ifdefs to handle the i386/x86-64 case. -Andi