From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752431Ab2E1BZl (ORCPT ); Sun, 27 May 2012 21:25:41 -0400 Received: from mga14.intel.com ([143.182.124.37]:38044 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751024Ab2E1BZk (ORCPT ); Sun, 27 May 2012 21:25:40 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.71,315,1320652800"; d="scan'208";a="104873301" Date: Mon, 28 May 2012 09:22:09 +0800 From: Feng Tang To: Don Zickus Cc: Ingo Molnar , Peter Zijlstra , , Subject: Re: [PATCH]x86, reboot: Fix a warning message triggered by stop_other_cpus() Message-ID: <20120528092209.60677c3b@feng-i7> In-Reply-To: <20120522133356.GW32472@redhat.com> References: <20120522105233.725be041@feng-i7> <20120522133356.GW32472@redhat.com> Organization: intel X-Mailer: Claws Mail 3.7.6 (GTK+ 2.22.0; i486-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Don, On Tue, 22 May 2012 09:33:56 -0400 Don Zickus wrote: > On Tue, May 22, 2012 at 10:52:33AM +0800, Feng Tang wrote: > > > > The root cause seems to be the default_send_IPI_mask_allbutself_phys() > > takes quiet some time (I measured it could be several ms) to complete > > sending NMIs to all the other 23 CPUs, and for HZ=250/1000 system, the > > I sent Ingo a patch (which he took in), that reverts this path to interrupts > again (and NMIs as a fallback if it fails). The problem will still exist > I assume though I don't know if it changes the timing characteristics. Thanks for your review and letting me know the revert which I just saw in the latest Linus' tree. And I think this new mechanism will greatly reduce the possibility, but it still exist as the old nmi_stop_other_cpus's implementation still exist. So Ingo, Could you review this patch? thanks, -Feng