Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753541AbZI3Uif (ORCPT ); Wed, 30 Sep 2009 16:38:35 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752513AbZI3Uif (ORCPT ); Wed, 30 Sep 2009 16:38:35 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:42787 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751697AbZI3Uie (ORCPT ); Wed, 30 Sep 2009 16:38:34 -0400 Date: Wed, 30 Sep 2009 22:38:18 +0200 From: Ingo Molnar To: Linus Torvalds Cc: Eric Dumazet , Arjan van de Ven , Martin Schwidefsky , Thomas Gleixner , John Stultz , Linux Kernel Mailing List , Peter Zijlstra Subject: Re: Linux 2.6.32-rc1 Message-ID: <20090930203818.GA24070@elte.hu> References: <4AC10365.7090802@gmail.com> <4AC2712C.4080901@gmail.com> <20090929232248.735bf4df@infradead.org> <20090930170754.0886ff2e@infradead.org> <20090930193204.GA16350@elte.hu> <4AC3BC89.2050404@gmail.com> <20090930202233.GA21890@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090930202233.GA21890@elte.hu> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.5 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1340 Lines: 38 * Ingo Molnar wrote: > * Linus Torvalds wrote: > > > On Wed, 30 Sep 2009, Eric Dumazet wrote: > > > > +#define cmpxchg64(ptr, o, n) \ > > > > +({ \ > > > > + __typeof__(*(ptr)) __ret; \ > > > > + __typeof__(*(ptr)) __old = (o); \ > > > > + __typeof__(*(ptr)) __new = (n); \ > > > > + alternative_io("call cmpxchg8b_emu", \ > > > > + "lock; cmpxchg8b (%%esi)" , \ > > > > + X86_FEATURE_CX8, \ > > > > + "=A" (__ret), \ > > > > + "S" ((ptr)), "0" (__old), \ > > > > + "b" ((unsigned int)__new), \ > > > > + "c" ((unsigned int)(__new>>32))); \ > > > > > > probably a "memory" clobber is needed, alternative_io() doesnt provide it. > > > > Yeah, good catch. > > Yeah - i'm testing this right now, it looks like something that could > explain the hang. Yeah - that was the cause of the hang. I've pushed out the updated patches - they should show up in this thread soon. I also updated the emulation implementation to your simpler variant. (will test that too) Ingo -- 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/