From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 69469C25B06 for ; Sun, 14 Aug 2022 16:37:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242865AbiHNQhT (ORCPT ); Sun, 14 Aug 2022 12:37:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51346 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242964AbiHNQgG (ORCPT ); Sun, 14 Aug 2022 12:36:06 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 347BC402F6; Sun, 14 Aug 2022 09:28:07 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id B8CDFB80B37; Sun, 14 Aug 2022 16:28:05 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3358AC433D6; Sun, 14 Aug 2022 16:28:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1660494484; bh=vB1QglllVjVmyLvs9SY4E5kAiJ6FpYz7jp3X8/Tkb20=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cg/c63HmxEAJbnZcGTwN4khJ3ic0YBNpVmVPpPms1k/AZPIwL7J5cGNf5wMO/tCPM Wi1b4njeet/ORQC5MX+oIUT1b7CNDS5ujCJitaI241zFaJ0Ugi8npZjNTEeyReOeiV fMFR9krKLwIXoD3v98Dr+gPDrmdxqCgOnS9LHJ8TsXHRehHjW0fEKJGBKBoM7rl+BW x3bn2m3xSVLUZmzFq0YpOSac2dl5Ahap4h8lMAo6UTBvRN+S11BC5xQPsCP0yba3m2 OJ8oCG/rIIeQmCGtrIIWx/AvVyySJlbEEZLQGVgeCI0+Tl1LkuHZK7w9ueCTTTFEVp pfIFShdrWIHuA== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Laurent Dufour , Michael Ellerman , Sasha Levin , pmladek@suse.com, akpm@linux-foundation.org, linux@rasmusvillemoes.dk, juri.lelli@redhat.com, john.ogness@linutronix.de, nixiaoming@huawei.com, frederic@kernel.org Subject: [PATCH AUTOSEL 5.10 09/19] watchdog: export lockup_detector_reconfigure Date: Sun, 14 Aug 2022 12:27:28 -0400 Message-Id: <20220814162739.2398217-9-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220814162739.2398217-1-sashal@kernel.org> References: <20220814162739.2398217-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Laurent Dufour [ Upstream commit 7c56a8733d0a2a4be2438a7512566e5ce552fccf ] In some circumstances it may be interesting to reconfigure the watchdog from inside the kernel. On PowerPC, this may helpful before and after a LPAR migration (LPM) is initiated, because it implies some latencies, watchdog, and especially NMI watchdog is expected to be triggered during this operation. Reconfiguring the watchdog with a factor, would prevent it to happen too frequently during LPM. Rename lockup_detector_reconfigure() as __lockup_detector_reconfigure() and create a new function lockup_detector_reconfigure() calling __lockup_detector_reconfigure() under the protection of watchdog_mutex. Signed-off-by: Laurent Dufour [mpe: Squash in build fix from Laurent, reported by Sachin] Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220713154729.80789-3-ldufour@linux.ibm.com Signed-off-by: Sasha Levin --- include/linux/nmi.h | 2 ++ kernel/watchdog.c | 21 ++++++++++++++++----- 2 files changed, 18 insertions(+), 5 deletions(-) diff --git a/include/linux/nmi.h b/include/linux/nmi.h index 750c7f395ca9..f700ff2df074 100644 --- a/include/linux/nmi.h +++ b/include/linux/nmi.h @@ -122,6 +122,8 @@ int watchdog_nmi_probe(void); int watchdog_nmi_enable(unsigned int cpu); void watchdog_nmi_disable(unsigned int cpu); +void lockup_detector_reconfigure(void); + /** * touch_nmi_watchdog - restart NMI watchdog timeout. * diff --git a/kernel/watchdog.c b/kernel/watchdog.c index 01bf977090dc..ec34d9f2eab2 100644 --- a/kernel/watchdog.c +++ b/kernel/watchdog.c @@ -518,7 +518,7 @@ int lockup_detector_offline_cpu(unsigned int cpu) return 0; } -static void lockup_detector_reconfigure(void) +static void __lockup_detector_reconfigure(void) { cpus_read_lock(); watchdog_nmi_stop(); @@ -538,6 +538,13 @@ static void lockup_detector_reconfigure(void) __lockup_detector_cleanup(); } +void lockup_detector_reconfigure(void) +{ + mutex_lock(&watchdog_mutex); + __lockup_detector_reconfigure(); + mutex_unlock(&watchdog_mutex); +} + /* * Create the watchdog thread infrastructure and configure the detector(s). * @@ -558,13 +565,13 @@ static __init void lockup_detector_setup(void) return; mutex_lock(&watchdog_mutex); - lockup_detector_reconfigure(); + __lockup_detector_reconfigure(); softlockup_initialized = true; mutex_unlock(&watchdog_mutex); } #else /* CONFIG_SOFTLOCKUP_DETECTOR */ -static void lockup_detector_reconfigure(void) +static void __lockup_detector_reconfigure(void) { cpus_read_lock(); watchdog_nmi_stop(); @@ -572,9 +579,13 @@ static void lockup_detector_reconfigure(void) watchdog_nmi_start(); cpus_read_unlock(); } +void lockup_detector_reconfigure(void) +{ + __lockup_detector_reconfigure(); +} static inline void lockup_detector_setup(void) { - lockup_detector_reconfigure(); + __lockup_detector_reconfigure(); } #endif /* !CONFIG_SOFTLOCKUP_DETECTOR */ @@ -614,7 +625,7 @@ static void proc_watchdog_update(void) { /* Remove impossible cpus to keep sysctl output clean. */ cpumask_and(&watchdog_cpumask, &watchdog_cpumask, cpu_possible_mask); - lockup_detector_reconfigure(); + __lockup_detector_reconfigure(); } /* -- 2.35.1