From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752297AbdINKzM (ORCPT ); Thu, 14 Sep 2017 06:55:12 -0400 Received: from terminus.zytor.com ([65.50.211.136]:34643 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752233AbdINKzJ (ORCPT ); Thu, 14 Sep 2017 06:55:09 -0400 Date: Thu, 14 Sep 2017 03:48:10 -0700 From: tip-bot for Thomas Gleixner Message-ID: Cc: npiggin@gmail.com, bigeasy@linutronix.de, mingo@kernel.org, torvalds@linux-foundation.org, uobergfe@redhat.com, benh@kernel.crashing.org, akpm@linux-foundation.org, mpe@ellerman.id.au, linux-kernel@vger.kernel.org, cmetcalf@mellanox.com, bp@alien8.de, dzickus@redhat.com, tglx@linutronix.de, peterz@infradead.org, hpa@zytor.com Reply-To: npiggin@gmail.com, torvalds@linux-foundation.org, mingo@kernel.org, bigeasy@linutronix.de, mpe@ellerman.id.au, akpm@linux-foundation.org, benh@kernel.crashing.org, uobergfe@redhat.com, bp@alien8.de, cmetcalf@mellanox.com, linux-kernel@vger.kernel.org, tglx@linutronix.de, dzickus@redhat.com, hpa@zytor.com, peterz@infradead.org In-Reply-To: <20170912194147.862865570@linutronix.de> References: <20170912194147.862865570@linutronix.de> To: linux-tip-commits@vger.kernel.org Subject: [tip:core/urgent] watchdog/core, powerpc: Make watchdog_nmi_reconfigure() two stage Git-Commit-ID: 6592ad2fcc8f15b4f99b36c1db7d9f65510c203b X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 6592ad2fcc8f15b4f99b36c1db7d9f65510c203b Gitweb: http://git.kernel.org/tip/6592ad2fcc8f15b4f99b36c1db7d9f65510c203b Author: Thomas Gleixner AuthorDate: Tue, 12 Sep 2017 21:37:16 +0200 Committer: Ingo Molnar CommitDate: Thu, 14 Sep 2017 11:41:07 +0200 watchdog/core, powerpc: Make watchdog_nmi_reconfigure() two stage Both the perf reconfiguration and the powerpc watchdog_nmi_reconfigure() need to be done in two steps. 1) Stop all NMIs 2) Read the new parameters and start NMIs Right now watchdog_nmi_reconfigure() is a combination of both. To allow a clean reconfiguration add a 'run' argument and split the functionality in powerpc. Signed-off-by: Thomas Gleixner Reviewed-by: Don Zickus Cc: Andrew Morton Cc: Benjamin Herrenschmidt Cc: Borislav Petkov Cc: Chris Metcalf Cc: Linus Torvalds Cc: Michael Ellerman Cc: Nicholas Piggin Cc: Peter Zijlstra Cc: Sebastian Siewior Cc: Ulrich Obergfell Cc: linuxppc-dev@lists.ozlabs.org Link: http://lkml.kernel.org/r/20170912194147.862865570@linutronix.de Signed-off-by: Ingo Molnar --- arch/powerpc/kernel/watchdog.c | 17 +++++++++-------- include/linux/nmi.h | 2 ++ kernel/watchdog.c | 31 ++++++++++++++++++++++--------- 3 files changed, 33 insertions(+), 17 deletions(-) diff --git a/arch/powerpc/kernel/watchdog.c b/arch/powerpc/kernel/watchdog.c index 5ded171..291af79 100644 --- a/arch/powerpc/kernel/watchdog.c +++ b/arch/powerpc/kernel/watchdog.c @@ -355,17 +355,18 @@ static void watchdog_calc_timeouts(void) wd_timer_period_ms = watchdog_thresh * 1000 * 2 / 5; } -void watchdog_nmi_reconfigure(void) +void watchdog_nmi_reconfigure(bool run) { int cpu; - watchdog_calc_timeouts(); - - for_each_cpu(cpu, &wd_cpus_enabled) - stop_wd_on_cpu(cpu); - - for_each_cpu_and(cpu, cpu_online_mask, &watchdog_cpumask) - start_wd_on_cpu(cpu); + if (!run) { + for_each_cpu(cpu, &wd_cpus_enabled) + stop_wd_on_cpu(cpu); + } else { + watchdog_calc_timeouts(); + for_each_cpu_and(cpu, cpu_online_mask, &watchdog_cpumask) + start_wd_on_cpu(cpu); + } } /* diff --git a/include/linux/nmi.h b/include/linux/nmi.h index 4a8d103..eee255b 100644 --- a/include/linux/nmi.h +++ b/include/linux/nmi.h @@ -103,6 +103,8 @@ static inline void arch_touch_nmi_watchdog(void) {} #endif #endif +void watchdog_nmi_reconfigure(bool run); + /** * touch_nmi_watchdog - restart NMI watchdog timeout. * diff --git a/kernel/watchdog.c b/kernel/watchdog.c index baae9fc..5693afd 100644 --- a/kernel/watchdog.c +++ b/kernel/watchdog.c @@ -112,17 +112,25 @@ void __weak watchdog_nmi_disable(unsigned int cpu) hardlockup_detector_perf_disable(); } -/* - * watchdog_nmi_reconfigure can be implemented to be notified after any - * watchdog configuration change. The arch hardlockup watchdog should - * respond to the following variables: +/** + * watchdog_nmi_reconfigure - Optional function to reconfigure NMI watchdogs + * @run: If false stop the watchdogs on all enabled CPUs + * If true start the watchdogs on all enabled CPUs + * + * The core call order is: + * watchdog_nmi_reconfigure(false); + * update_variables(); + * watchdog_nmi_reconfigure(true); + * + * The second call which starts the watchdogs again guarantees that the + * following variables are stable across the call. * - watchdog_enabled * - watchdog_thresh * - watchdog_cpumask - * - sysctl_hardlockup_all_cpu_backtrace - * - hardlockup_panic + * + * After the call the variables can be changed again. */ -void __weak watchdog_nmi_reconfigure(void) { } +void __weak watchdog_nmi_reconfigure(bool run) { } #ifdef CONFIG_SOFTLOCKUP_DETECTOR @@ -515,10 +523,12 @@ static void softlockup_unpark_threads(void) static void softlockup_reconfigure_threads(bool enabled) { + watchdog_nmi_reconfigure(false); softlockup_park_all_threads(); set_sample_period(); if (enabled) softlockup_unpark_threads(); + watchdog_nmi_reconfigure(true); } /* @@ -559,7 +569,11 @@ static inline void watchdog_unpark_threads(void) { } static inline int watchdog_enable_all_cpus(void) { return 0; } static inline void watchdog_disable_all_cpus(void) { } static inline void softlockup_init_threads(void) { } -static inline void softlockup_reconfigure_threads(bool enabled) { } +static void softlockup_reconfigure_threads(bool enabled) +{ + watchdog_nmi_reconfigure(false); + watchdog_nmi_reconfigure(true); +} #endif /* !CONFIG_SOFTLOCKUP_DETECTOR */ static void __lockup_detector_cleanup(void) @@ -599,7 +613,6 @@ static void proc_watchdog_update(void) /* Remove impossible cpus to keep sysctl output clean. */ cpumask_and(&watchdog_cpumask, &watchdog_cpumask, cpu_possible_mask); softlockup_reconfigure_threads(watchdog_enabled && watchdog_thresh); - watchdog_nmi_reconfigure(); } /*