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 08A49C32772 for ; Tue, 23 Aug 2022 12:03:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1359165AbiHWMDP (ORCPT ); Tue, 23 Aug 2022 08:03:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51772 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1359307AbiHWMBJ (ORCPT ); Tue, 23 Aug 2022 08:01:09 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2E6C4D9E83; Tue, 23 Aug 2022 02:35:41 -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 B4694B81C89; Tue, 23 Aug 2022 09:34:41 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 221ECC433C1; Tue, 23 Aug 2022 09:34:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1661247280; bh=oxPVV2m77GTW/SkQcS6bwbMb6sbrxTJSZLBOV8s6PN0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=i1Y7Nko8rc10UpsnxSX2LpMiW6SRNreCX5Sxc3qqqwcLW4J2Ru3bbxC4dhAA/F6+g 6oJlK3hqhTlblqhL4oAGoSAwkHPFlQeIo+rgYwHPzIhUr3ElZax6q/W592ixXQF3if z6TlwPLvxp7dl676gs2IIZZmlKo2a4bw8DXfgoxg= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Laurent Dufour , Michael Ellerman , Sasha Levin Subject: [PATCH 5.4 376/389] watchdog: export lockup_detector_reconfigure Date: Tue, 23 Aug 2022 10:27:34 +0200 Message-Id: <20220823080131.258753866@linuxfoundation.org> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220823080115.331990024@linuxfoundation.org> References: <20220823080115.331990024@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@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 9003e29cde46..e972d1ae1ee6 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 cbd3cf503c90..a3d0e928305c 100644 --- a/kernel/watchdog.c +++ b/kernel/watchdog.c @@ -568,7 +568,7 @@ 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(); @@ -588,6 +588,13 @@ 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). * @@ -608,13 +615,13 @@ 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(); @@ -622,9 +629,13 @@ 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 */ @@ -664,7 +675,7 @@ 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