Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752976AbZI2VWg (ORCPT ); Tue, 29 Sep 2009 17:22:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752562AbZI2VWg (ORCPT ); Tue, 29 Sep 2009 17:22:36 -0400 Received: from casper.infradead.org ([85.118.1.10]:40780 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752144AbZI2VWf (ORCPT ); Tue, 29 Sep 2009 17:22:35 -0400 Date: Tue, 29 Sep 2009 23:22:48 +0200 From: Arjan van de Ven To: Linus Torvalds Cc: Eric Dumazet , Martin Schwidefsky , Thomas Gleixner , John Stultz , Linux Kernel Mailing List , Peter Zijlstra , Ingo Molnar Subject: Re: Linux 2.6.32-rc1 Message-ID: <20090929232248.735bf4df@infradead.org> In-Reply-To: References: <4AC060AE.1090401@gmail.com> <20090928191506.40b61793@mschwide.boeblingen.de.ibm.com> <4AC10365.7090802@gmail.com> <4AC2712C.4080901@gmail.com> Organization: Intel X-Mailer: Claws Mail 3.7.2 (GTK+ 2.16.6; i586-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1314 Lines: 35 On Tue, 29 Sep 2009 14:17:58 -0700 (PDT) Linus Torvalds wrote: > > > On Tue, 29 Sep 2009, Eric Dumazet wrote: > > > > Checking this commit, I believe problem comes from cmpxchg(), which > > doesnt handle 64 bit on X86_32 (no compilation error, and null > > operation :( ) > > Wow. That's broken. Very nasty silent failure. > > > 1) Use cmpxchg64() > > Clearly better than what we have now, although cmpxchg64 does result > is some really disgusting code. We will use a bare CMPXCHG64 only if > you compile for PAE right now - so even if you tell Kconfig that you > want to compile for a modern CPU, we won't be doing that whole > cmpxchg64b thing directly, we'll inline some really disgusting code. can't we use alternatives() for this, to patch cmpxchg64 in ? I mean.. it'll be commonly supported nowadays.. the fallback to it not being supported could be a bit slower by now... -- Arjan van de Ven Intel Open Source Technology Centre For development, discussion and tips for power savings, visit http://www.lesswatts.org -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/