From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753755Ab2DWRJH (ORCPT ); Mon, 23 Apr 2012 13:09:07 -0400 Received: from acsinet15.oracle.com ([141.146.126.227]:19094 "EHLO acsinet15.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754668Ab2DWRJD (ORCPT ); Mon, 23 Apr 2012 13:09:03 -0400 Date: Mon, 23 Apr 2012 13:03:27 -0400 From: Konrad Rzeszutek Wilk To: "H. Peter Anvin" Cc: "Luck, Tony" , "Liu, Jinsong" , "xen-devel@lists.xensource.com" , "x86@kernel.org" , "linux-kernel@vger.kernel.org" , Borislav Petkov , Thomas Gleixner , Ingo Molnar , "linux-edac@vger.kernel.org" Subject: Re: [Xen-devel] [PATCH 1/3] Add mcelog support for xen platform Message-ID: <20120423170327.GC22364@phenom.dumpdata.com> References: <20120421041454.GA29704@phenom.dumpdata.com> <20120421104502.GB17005@aftab.osrc.amd.com> <3908561D78D1C84285E8C5FCA982C28F170EF841@ORSMSX104.amr.corp.intel.com> <4F958098.1050402@zytor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4F958098.1050402@zytor.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-Source-IP: ucsinet22.oracle.com [156.151.31.94] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Apr 23, 2012 at 09:17:28AM -0700, H. Peter Anvin wrote: > On 04/23/2012 08:27 AM, Luck, Tony wrote: > >> Because, if you'd hooked into it, just imagine one fine day, when we > >> remove mcelog support, what screaming the xen people will be doing when > >> mcelog doesn't work anymore. > > > > Agreed. Even before we get to deleting mcelog, "struct mce" can change (new > > fields could be added) ... and you don't want to have your hypervisor to > > have to know which version of Linux it is talking to. > > This is a great example on the fundamental problem with Xen, or rather > the approach that Xen has taken of grabbing random kernel internals and > claiming them as APIs (or, in some cases even as ABIs.) A lot of these I am _not_ claiming that. If I left you with that impression from my responses - my fault for not getting my point across (the sleep deprevation is probably not helping either). I am _not_ stating that the usage of 'mce_log' or 'struct mce' MUST remain the same from now on. No. I am saying that the driver will be changed lock-step as Tony and Boris see fit in changing the functions. And currently the way the existing MCE drivers do this - is by using mce_log. This driver does is too - since the in-tree drivers do it this way. When they change to use a different mechanism - this driver will as well. > have had problems that are now very nearly unfixable, and that has > seriously stalled out the ability of evolve the Linux kernel in some > areas. Note that the cost of this is borne by the development > community, not by the Xen maintainers. The ones I know that you are unhappy about are the MMU paravirt interfaces and I did mention to you that once some prototype work is done and it showed success, I will work on removing said support. Why don't you send me your unhappy list so that is on my radar as well please? > > -hpa > > -- > H. Peter Anvin, Intel Open Source Technology Center > I work for Intel. I don't speak on their behalf. > > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xen.org > http://lists.xen.org/xen-devel