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 lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 1E666C433F5 for ; Fri, 6 May 2022 00:15:55 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4KvWLd5Txfz3fys for ; Fri, 6 May 2022 10:15:53 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.a=rsa-sha256 header.s=Intel header.b=W+KP8uHe; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=none (no SPF record) smtp.mailfrom=linux.intel.com (client-ip=192.55.52.115; helo=mga14.intel.com; envelope-from=ricardo.neri-calderon@linux.intel.com; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.a=rsa-sha256 header.s=Intel header.b=W+KP8uHe; dkim-atps=neutral Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4KvVzY42Fdz3c8s for ; Fri, 6 May 2022 09:59:21 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1651795161; x=1683331161; h=from:to:cc:subject:date:message-id:in-reply-to: references; bh=CEzigczvRyU1oQzEnVej8ViYVBfDe59Bvau/LRgGfAw=; b=W+KP8uHeRkvUtM5OFzpaJjZgoPML5buCP51xu0xFx39QJ79Q3lkZC7H/ 2N542T1Xf4w5vWjlddB1kGAS/4GtclBNGk/d9wGeNHaOYhF2I7lcZZASt Vf8+n34uFxHXIqBnmXio5SXcxPU5o6IZqRM5JTh+cieYsFivgFimocMZ7 ENZ8FZ+Nl00mC+oo94bBJywaTsChheTbmICBqf75Yvi7VtJo+GtNmBI6P aSSp8TQmsqRfr9dLO0xqxcdUGYP2tafuqDwjkMW2IUG4RMuDog+cNaihr /xjy+XR3/IuC16Kph0HoLXRE6ghQwPE26hog93hMzI8JKo5BUMtXiZKwl Q==; X-IronPort-AV: E=McAfee;i="6400,9594,10338"; a="268437342" X-IronPort-AV: E=Sophos;i="5.91,203,1647327600"; d="scan'208";a="268437342" Received: from orsmga004.jf.intel.com ([10.7.209.38]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 May 2022 16:57:56 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.91,203,1647327600"; d="scan'208";a="694914451" Received: from ranerica-svr.sc.intel.com ([172.25.110.23]) by orsmga004.jf.intel.com with ESMTP; 05 May 2022 16:57:56 -0700 From: Ricardo Neri To: Thomas Gleixner , x86@kernel.org Subject: [PATCH v6 27/29] watchdog: Expose lockup_detector_reconfigure() Date: Thu, 5 May 2022 17:00:06 -0700 Message-Id: <20220506000008.30892-28-ricardo.neri-calderon@linux.intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20220506000008.30892-1-ricardo.neri-calderon@linux.intel.com> References: <20220506000008.30892-1-ricardo.neri-calderon@linux.intel.com> X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "Ravi V. Shankar" , Andi Kleen , linuxppc-dev@lists.ozlabs.org, Joerg Roedel , Ricardo Neri , Stephane Eranian , linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, Tony Luck , Nicholas Piggin , Suravee Suthikulpanit , Ricardo Neri , Andrew Morton , David Woodhouse , Lu Baolu Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" When there are multiple implementations of the NMI watchdog, there may be situations in which switching from one to another is needed. If the time- stamp counter becomes unstable, the HPET-based NMI watchdog can no longer be used. Similarly, the HPET-based NMI watchdog relies on tsc_khz and needs to be informed when it is refined. Reloading the NMI watchdog or switching to another hardlockup detector can be done cleanly by updating the arch-specific stub and then reconfiguring the whole lockup detector. Expose lockup_detector_reconfigure() to achieve this goal. Cc: Andi Kleen Cc: Nicholas Piggin Cc: Stephane Eranian Cc: "Ravi V. Shankar" Cc: iommu@lists.linux-foundation.org Cc: linuxppc-dev@lists.ozlabs.org Cc: x86@kernel.org Reviewed-by: Tony Luck Signed-off-by: Ricardo Neri --- Changes since v5: * None Changes since v4: * Switching to the perf-based lockup detector under the hood is hacky. Instead, reconfigure the whole lockup detector. Changes since v3: * None Changes since v2: * Introduced this patch. Changes since v1: * N/A --- include/linux/nmi.h | 2 ++ kernel/watchdog.c | 4 ++-- 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/include/linux/nmi.h b/include/linux/nmi.h index cf12380e51b3..73827a477288 100644 --- a/include/linux/nmi.h +++ b/include/linux/nmi.h @@ -16,6 +16,7 @@ void lockup_detector_init(void); void lockup_detector_soft_poweroff(void); void lockup_detector_cleanup(void); bool is_hardlockup(void); +void lockup_detector_reconfigure(void); extern int watchdog_user_enabled; extern int nmi_watchdog_user_enabled; @@ -37,6 +38,7 @@ extern int sysctl_hardlockup_all_cpu_backtrace; static inline void lockup_detector_init(void) { } static inline void lockup_detector_soft_poweroff(void) { } static inline void lockup_detector_cleanup(void) { } +static inline void lockup_detector_reconfigure(void) { } #endif /* !CONFIG_LOCKUP_DETECTOR */ #ifdef CONFIG_SOFTLOCKUP_DETECTOR diff --git a/kernel/watchdog.c b/kernel/watchdog.c index 6443841a755f..e5b67544f8c8 100644 --- a/kernel/watchdog.c +++ b/kernel/watchdog.c @@ -537,7 +537,7 @@ int lockup_detector_offline_cpu(unsigned int cpu) return 0; } -static void lockup_detector_reconfigure(void) +void lockup_detector_reconfigure(void) { cpus_read_lock(); watchdog_nmi_stop(); @@ -579,7 +579,7 @@ static __init void lockup_detector_setup(void) } #else /* CONFIG_SOFTLOCKUP_DETECTOR */ -static void lockup_detector_reconfigure(void) +void lockup_detector_reconfigure(void) { cpus_read_lock(); watchdog_nmi_stop(); -- 2.17.1