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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 0D8F8C6778A for ; Thu, 5 Jul 2018 06:00:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BFD672417D for ; Thu, 5 Jul 2018 06:00:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BFD672417D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753504AbeGEGAa (ORCPT ); Thu, 5 Jul 2018 02:00:30 -0400 Received: from ozlabs.org ([203.11.71.1]:59747 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753311AbeGEGA3 (ORCPT ); Thu, 5 Jul 2018 02:00:29 -0400 Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPSA id 41LnJp52F1z9s2R; Thu, 5 Jul 2018 16:00:26 +1000 (AEST) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au From: Michael Ellerman To: Gautham R Shenoy , Vaidyanathan Srinivasan Cc: "Gautham R. Shenoy" , akshay.adiga@linux.vnet.ibm.com, Nicholas Piggin , "Rafael J. Wysocki" , Daniel Lezcano , linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org Subject: Re: [PATCH] cpuidle:powernv: Add the CPUIDLE_FLAG_POLLING for snooze In-Reply-To: <20180703150348.GA13348@in.ibm.com> References: <1530595456-32352-1-git-send-email-ego@linux.vnet.ibm.com> <20180703140616.GA13660@drishya.in.ibm.com> <20180703150348.GA13348@in.ibm.com> Date: Thu, 05 Jul 2018 16:00:23 +1000 Message-ID: <87a7r6kyrs.fsf@concordia.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Gautham R Shenoy writes: > On Tue, Jul 03, 2018 at 07:36:16PM +0530, Vaidyanathan Srinivasan wrote: >> * Gautham R Shenoy [2018-07-03 10:54:16]: >> >> > From: "Gautham R. Shenoy" >> > >> > In the situations where snooze is the only cpuidle state due to >> > firmware not exposing any platform idle states, the idle CPUs will >> > remain in snooze for a long time with interrupts disabled causing the >> > Hard-lockup detector to complain. >> >> snooze_loop() will spin in SMT low priority with interrupt enabled. We >> have local_irq_enable() before we get into the snooze loop. >> Since this is a polling state, we should wakeup without an interrupt >> and hence we set TIF_POLLING_NRFLAG as well. >> > > You are right. We have a local_irq_enable() inside the snooze_loop. >> >> > watchdog: CPU 51 detected hard LOCKUP on other CPUs 59 >> > watchdog: CPU 51 TB:535296107736, last SMP heartbeat TB:527472229239 (15281ms ago) >> > watchdog: CPU 59 Hard LOCKUP >> > watchdog: CPU 59 TB:535296252849, last heartbeat TB:526554725466 (17073ms ago) >> >> hmm.. not sure why watchdog will complain, maybe something more is >> going on. > > Will look into this Vaidy. I'll wait for a v2. cheers