From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751335AbYJaLMr (ORCPT ); Fri, 31 Oct 2008 07:12:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750761AbYJaLMi (ORCPT ); Fri, 31 Oct 2008 07:12:38 -0400 Received: from gw.goop.org ([64.81.55.164]:53653 "EHLO mail.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750735AbYJaLMi (ORCPT ); Fri, 31 Oct 2008 07:12:38 -0400 Message-ID: <490AE820.1010301@goop.org> Date: Fri, 31 Oct 2008 22:12:32 +1100 From: Jeremy Fitzhardinge User-Agent: Thunderbird 2.0.0.17 (X11/20081009) MIME-Version: 1.0 To: Ingo Molnar CC: Suresh Siddha , "jens.axboe@oracle.com" , "paulmck@linux.vnet.ibm.com" , "nickpiggin@yahoo.com.au" , "torvalds@linux-foundation.org" , "linux-kernel@vger.kernel.org" , "Mallick, Asit K" Subject: Re: [patch] generic-ipi: fix the smp_mb() placement References: <20081029224229.GK30573@linux-os.sc.intel.com> <20081030185322.GE17822@elte.hu> <20081030202322.GM30573@linux-os.sc.intel.com> <490A9337.6090504@goop.org> <20081031093924.GG30317@elte.hu> In-Reply-To: <20081031093924.GG30317@elte.hu> X-Enigmail-Version: 0.95.6 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Ingo Molnar wrote: > * Jeremy Fitzhardinge wrote: > > >> Suresh Siddha wrote: >> >>> We didn't see the lockup in our tests but Xen folks reported similar failures >>> with their smp call function code. >>> >>> >> ...really? I don't remember anything like that, but perhaps I'm >> forgetting something. In Xen the IPI is sent with a hypercall, >> which is definitely a solid enough barrier for these purposes. >> > > i think Suresh might be referring to some of the fragilities Xen had > with generic-ipi. But those AFAICT were due to the on-stack lifetime > bug that Nick fixed via the kmalloc? v2.6.26-ish issue. Right, that's all I could think of. J