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 X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D8D0AC43219 for ; Fri, 3 May 2019 07:29:29 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 8BA8620B7C for ; Fri, 3 May 2019 07:29:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8BA8620B7C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 44wP074VVCzDqVq for ; Fri, 3 May 2019 17:29:27 +1000 (AEST) Received: from ozlabs.org (bilbo.ozlabs.org [203.11.71.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 44wNKM6RTbzDqTJ for ; Fri, 3 May 2019 16:59:19 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au Received: by ozlabs.org (Postfix, from userid 1034) id 44wNKM3RTJz9s9y; Fri, 3 May 2019 16:59:19 +1000 (AEST) X-powerpc-patch-notification: thanks X-powerpc-patch-commit: 7ae3f6e130e8dc6188b59e3b4ebc2f16e9c8d053 X-Patchwork-Hint: ignore In-Reply-To: <20190409044005.26446-1-npiggin@gmail.com> To: Nicholas Piggin , linuxppc-dev@lists.ozlabs.org From: Michael Ellerman Subject: Re: [PATCH v2] powerpc/watchdog: Use hrtimers for per-CPU heartbeat Message-Id: <44wNKM3RTJz9s9y@ozlabs.org> Date: Fri, 3 May 2019 16:59:19 +1000 (AEST) 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: "Gautham R . Shenoy" , Ravikumar Bangoria , Nicholas Piggin Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Tue, 2019-04-09 at 04:40:05 UTC, Nicholas Piggin wrote: > Using a jiffies timer creates a dependency on the tick_do_timer_cpu > incrementing jiffies. If that CPU has locked up and jiffies is not > incrementing, the watchdog heartbeat timer for all CPUs stops and > creates false positives and confusing warnings on local CPUs, and > also causes the SMP detector to stop, so the root cause is never > detected. > > Fix this by using hrtimer based timers for the watchdog heartbeat, > like the generic kernel hardlockup detector. > > Cc: Gautham R. Shenoy > Reported-by: Ravikumar Bangoria > Signed-off-by: Nicholas Piggin > Tested-by: Ravi Bangoria > Reported-by: Ravi Bangoria > Reviewed-by: Gautham R. Shenoy Applied to powerpc next, thanks. https://git.kernel.org/powerpc/c/7ae3f6e130e8dc6188b59e3b4ebc2f16 cheers