Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757284AbXJAVnq (ORCPT ); Mon, 1 Oct 2007 17:43:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753185AbXJAVnj (ORCPT ); Mon, 1 Oct 2007 17:43:39 -0400 Received: from cantor2.suse.de ([195.135.220.15]:47948 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753175AbXJAVni (ORCPT ); Mon, 1 Oct 2007 17:43:38 -0400 From: Andi Kleen To: Thomas Gleixner Subject: Re: nmi_watchdog fix for x86_64 to be more like i386 Date: Mon, 1 Oct 2007 23:41:52 +0200 User-Agent: KMail/1.9.1 Cc: Arjan van de Ven , David Bahi , LKML , linux-rt-users@vger.kernel.org, Andrew Morton , Ingo Molnar , Gregory Haskins References: <46FA4A800200006C000192FE@sinclair.provo.novell.com> <20071001125626.32eb6d0b@laptopd505.fenrus.org> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200710012341.53169.ak@suse.de> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1064 Lines: 28 > IRQ_NOBALANCING is not preventing cpu unplug. It moves the affinity to the > next CPU, but the check in NMI watchdog for CPU == 0 would not longer > work. That cannot happen right now because cpu_disable() on both i386/x86-64 reject CPU #0. So just setting IRQ_NOBALANCING is sufficient and both do that already. I was wrong earlier in being concerned about this. > int tick_do_broadcast(cpumask_t mask) > @@ -137,6 +147,7 @@ int tick_do_broadcast(cpumask_t mask) > cpu_clear(cpu, mask); > td = &per_cpu(tick_cpu_device, cpu); > td->evtdev->event_handler(td->evtdev); > + tick_broadcast_account(cpu); That would not handle the case with a single CPU running only irq 0 but not broadcasting I think. I believe ftp://ftp.firstfloor.org/pub/ak/x86_64/quilt/patches/fix-watchdog is the correct fix -Andi - 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/