Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757779AbXLJLuT (ORCPT ); Mon, 10 Dec 2007 06:50:19 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757479AbXLJLtq (ORCPT ); Mon, 10 Dec 2007 06:49:46 -0500 Received: from rv-out-0910.google.com ([209.85.198.191]:7893 "EHLO rv-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757464AbXLJLto (ORCPT ); Mon, 10 Dec 2007 06:49:44 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=iIsPeIk19FXTR3eyYsJBBghqeKxkRfdPtyYzpWbojnRe/FX4DaLiVmpsB6ufjsO7cw8Zr2y+8pdNz3LP4mulSWxTjPChbhktoI7uDNYQVaWPh5qPs8WGmAfyt71D7BvQjYcnysp1L+dtYKXI15TV3Jg926J5n/0W1KC2GPB+tC4= Message-ID: Date: Mon, 10 Dec 2007 17:19:43 +0530 From: "Gautham R Shenoy" To: "Ingo Molnar" Subject: Re: broken suspend (sched related) [Was: 2.6.24-rc4-mm1] Cc: "Gautham R Shenoy" , "Jiri Slaby" , "Andrew Morton" , linux-kernel@vger.kernel.org, "Rafael J. Wysocki" , "Arjan van de Ven" , "Thomas Gleixner" , "Linux-pm mailing list" , "Dipankar Sarma" In-Reply-To: <20071210112832.GA20189@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <475A629C.7010408@gmail.com> <475B24F4.3090904@gmail.com> <20071209074647.GE22981@elte.hu> <20071210081952.GA7215@in.ibm.com> <475CFF01.2090502@gmail.com> <20071210091052.GA14487@elte.hu> <20071210101500.GB12880@in.ibm.com> <20071210102157.GB31103@elte.hu> <20071210110818.GC12880@in.ibm.com> <20071210112832.GA20189@elte.hu> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1807 Lines: 54 On Dec 10, 2007 4:58 PM, Ingo Molnar wrote: > > * Gautham R Shenoy wrote: > > > > say we've got 100 CPUs, so we've got 100 watchdog tasks running - > > > one for each CPU. Checking for hung tasks is a global operation not > > > a per-CPU operation (we iterate over the global tasklist), hence > > > only one CPU should really be calling this function. That > > > online-cpus logic achieves this by picking a single CPU. Perhaps it > > > would be better to keep a hung_task_checker_cpu variable that is > > > driven from a CPU-hotplug-down notifier? That way if a CPU is > > > brought down we can update hung_task_checker_cpu to another, > > > still-online CPU. (this would also be faster, because event-driven) > > > > Do you mean something like this? > > yeah, thanks - queued it up. Stupid me! I forgot to remove the local variable check_cpu in static int watchdog(void * __bind_cpu). Could you please correct it before applying? > > one question: > > > +static int check_cpu = -1; > > > case CPU_ONLINE: > > case CPU_ONLINE_FROZEN: > > + check_cpu = any_online_cpu(cpu_online_map); > > wake_up_process(per_cpu(watchdog_task, hotcpu)); > > break; > > do we bring the boot CPU online too - i.e. will check_cpu be properly > initialized on UP too? Yes, it does. > > Ingo > Thanks and Regards gautham. -- Gautham R Shenoy Linux Technology Center IBM India. "Freedom comes with a price tag of responsibility, which is still a bargain, because Freedom is priceless!" -- 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/