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=-2.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_PASS,T_DKIMWL_WL_HIGH,USER_AGENT_MUTT 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 4F67DC433F5 for ; Tue, 28 Aug 2018 02:25:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0A444208B1 for ; Tue, 28 Aug 2018 02:25:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="UQ2CHAXj" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0A444208B1 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org 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 S1727146AbeH1GPL (ORCPT ); Tue, 28 Aug 2018 02:15:11 -0400 Received: from mail.kernel.org ([198.145.29.99]:50960 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725796AbeH1GPL (ORCPT ); Tue, 28 Aug 2018 02:15:11 -0400 Received: from localhost (LFbn-NCY-1-241-207.w83-194.abo.wanadoo.fr [83.194.85.207]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 4D35C2084C; Tue, 28 Aug 2018 02:25:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1535423149; bh=f53YcoBdQlnMX0T3h5u2LbWAVRs9EUayMMp/75ouAPY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=UQ2CHAXjrPU2fJbn9TCulQBk+5vF1HFeW9D8fcU5EqKWjdLRiXziZxrQa3rsVuTCT UY9ythDb1fkmQoZOAGJv4ItZD70SNKv1zMogeWv0VxzEX3oTZ9ZRpXtO3nmUWb6PT+ UlshwmlI0Mv2VbxeIcWL/JKSrmhwzX3e2Lkby/10= Date: Tue, 28 Aug 2018 04:25:47 +0200 From: Frederic Weisbecker To: Heiner Kallweit Cc: Thomas Gleixner , Anna-Maria Gleixner , Linux Kernel Mailing List , Grygorii Strashko Subject: Re: Fix 80d20d35af1e ("nohz: Fix local_timer_softirq_pending()") may have revealed another problem Message-ID: <20180828022545.GA25943@lerouge> References: <8b93f213-fe67-f132-f3f5-5b17995ec63d@gmail.com> <20180824041245.GA2730@lerouge> <67ce38dc-1f00-55c6-f9ae-2dec00172cf6@gmail.com> <20180824143056.GC2730@lerouge> MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="W/nzBZO5zC0uMSeA" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --W/nzBZO5zC0uMSeA Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Fri, Aug 24, 2018 at 07:06:32PM +0200, Heiner Kallweit wrote: > On 24.08.2018 16:30, Frederic Weisbecker wrote: > >> Can you try the one I posted in this thread: > >> > >> https://lkml.kernel.org/r/alpine.DEB.2.21.1808240851420.1668@nanos.tec.linutronix.de > >> > >> Also below for reference. > >> > >> Thanks, > >> > >> tglx > >> > >> 8<---------------- > >> diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c > >> index 5b33e2f5c0ed..6aab9d54a331 100644 > >> --- a/kernel/time/tick-sched.c > >> +++ b/kernel/time/tick-sched.c > >> @@ -888,7 +888,7 @@ static bool can_stop_idle_tick(int cpu, struct tick_sched *ts) > >> if (unlikely(local_softirq_pending() && cpu_online(cpu))) { > >> static int ratelimit; > >> > >> - if (ratelimit < 10 && > >> + if (ratelimit < 10 && !in_softirq() && > >> (local_softirq_pending() & SOFTIRQ_STOP_IDLE_MASK)) { > >> pr_warn("NOHZ: local_softirq_pending %02x\n", > >> (unsigned int) local_softirq_pending()); > > > > I fear it may not work in his case because it happens in -next and we don't stop > > the idle tick from IRQ tail anymore. So we shouldn't be interrupting a softirq > > in this path. Still it's worth trying, I may well be missing something. > > > > Thanks. > > > I tested it and Frederic is right, it doesn't help. Can it be somehow related to > the cpu being brought down during suspend? Because I get the warning only during > suspend when the cpu is inactive already (but still online). It's hard to tell, I haven't been able to reproduce on suspend to disk/mem. Does this script eventually trigger it after some time? --W/nzBZO5zC0uMSeA Content-Type: text/plain; charset=us-ascii Content-Disposition: attachment; filename=hotplug_fun #!/bin/bash do_hotplug() { for i in $(seq 1 $2) do echo $1 > /sys/devices/system/cpu/cpu$i/online done } LAST_CPU=$(($(nproc)-1)) while true do do_hotplug 0 $LAST_CPU do_hotplug 1 $LAST_CPU done --W/nzBZO5zC0uMSeA--