From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754298AbYDWV5G (ORCPT ); Wed, 23 Apr 2008 17:57:06 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752120AbYDWV4y (ORCPT ); Wed, 23 Apr 2008 17:56:54 -0400 Received: from rgminet01.oracle.com ([148.87.113.118]:14936 "EHLO rgminet01.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752068AbYDWV4x (ORCPT ); Wed, 23 Apr 2008 17:56:53 -0400 Date: Wed, 23 Apr 2008 14:55:17 -0700 From: Randy Dunlap To: Dimitri Sivanich Cc: linux-kernel@vger.kernel.org, Thomas Gleixner , Peter Zijlstra , Ingo Molnar Subject: Re: [PATCH] disable softlockup detection at boottime Message-Id: <20080423145517.c786015b.randy.dunlap@oracle.com> In-Reply-To: <20080423201613.GA8546@sgi.com> References: <20080423201613.GA8546@sgi.com> Organization: Oracle Linux Eng. X-Mailer: Sylpheed 2.4.7 (GTK+ 2.8.10; x86_64-unknown-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Brightmail-Tracker: AAAAAQAAAAI= X-Brightmail-Tracker: AAAAAQAAAAI= X-Whitelist: TRUE X-Whitelist: TRUE Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 23 Apr 2008 15:16:13 -0500 Dimitri Sivanich wrote: > This patch allows softlockup detection to be disabled by specifying > a boottime parameter. Seems to be missing (a) justification/why and (b) entry in Documentation/kernel-parameters.txt > Signed-off-by: Dimitri Sivanich > > Index: linux/kernel/softlockup.c > =================================================================== > --- linux.orig/kernel/softlockup.c 2008-04-23 13:50:06.000000000 -0500 > +++ linux/kernel/softlockup.c 2008-04-23 14:39:36.267398531 -0500 > @@ -24,6 +24,7 @@ static DEFINE_PER_CPU(unsigned long, tou > static DEFINE_PER_CPU(unsigned long, print_timestamp); > static DEFINE_PER_CPU(struct task_struct *, watchdog_task); > > +static int __read_mostly softlockup_off; > static int __read_mostly did_panic; > unsigned long __read_mostly softlockup_thresh = 60; > > @@ -53,7 +54,8 @@ void touch_softlockup_watchdog(void) > { > int this_cpu = raw_smp_processor_id(); > > - __raw_get_cpu_var(touch_timestamp) = get_timestamp(this_cpu); > + if (!softlockup_off) > + __raw_get_cpu_var(touch_timestamp) = get_timestamp(this_cpu); > } > EXPORT_SYMBOL(touch_softlockup_watchdog); > > @@ -61,6 +63,9 @@ void touch_all_softlockup_watchdogs(void > { > int cpu; > > + if (softlockup_off) > + return; > + > /* Cause each CPU to re-update its timestamp rather than complain */ > for_each_online_cpu(cpu) > per_cpu(touch_timestamp, cpu) = 0; > @@ -79,6 +84,9 @@ void softlockup_tick(void) > struct pt_regs *regs = get_irq_regs(); > unsigned long now; > > + if (softlockup_off) > + return; > + > if (touch_timestamp == 0) { > touch_softlockup_watchdog(); > return; > @@ -306,9 +314,19 @@ __init void spawn_softlockup_task(void) > void *cpu = (void *)(long)smp_processor_id(); > int err = cpu_callback(&cpu_nfb, CPU_UP_PREPARE, cpu); > > + if (softlockup_off) > + return; > + > BUG_ON(err == NOTIFY_BAD); > cpu_callback(&cpu_nfb, CPU_ONLINE, cpu); > register_cpu_notifier(&cpu_nfb); > > atomic_notifier_chain_register(&panic_notifier_list, &panic_block); > } > + > +static int __init disable_softlockup_detection(char *str) > +{ > + softlockup_off = 1; > + return 1; > +} > +__setup("nosoftlockup", disable_softlockup_detection); > -- --- ~Randy