From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761416Ab3BNA4A (ORCPT ); Wed, 13 Feb 2013 19:56:00 -0500 Received: from terminus.zytor.com ([198.137.202.10]:46529 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753167Ab3BNAz7 (ORCPT ); Wed, 13 Feb 2013 19:55:59 -0500 Message-ID: <511C35CB.2010103@zytor.com> Date: Wed, 13 Feb 2013 16:54:35 -0800 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130110 Thunderbird/17.0.2 MIME-Version: 1.0 To: Linus Torvalds CC: Ingo Molnar , Linux Kernel Mailing List , Peter Zijlstra , Rik van Riel , rostedt@goodmiss.org, aquini@redhat.com, Andrew Morton , Thomas Gleixner , Michel Lespinasse , linux-tip-commits@vger.kernel.org Subject: Re: [tip:core/locking] x86/smp: Move waiting on contended ticket lock out of line References: <20130206150403.006e5294@cuia.bos.redhat.com> In-Reply-To: X-Enigmail-Version: 1.5 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/13/2013 10:30 AM, Linus Torvalds wrote: > > Sadly, gcc doesn't seem to allow specifying which registers are > clobbered any easy way, which means that both the caller and the > callee *both* tend to need to have some asm interface. So we bothered > to do this for __read_lock_failed, but we have *not* bothered to do > the same for the otherwise very similar __mutex_fastpath_lock() case, > for example. > It does for the callee, but only on a whole-file basis. It would be a lot nicer if we could do it with function attributes. -hpa