From patchwork Fri Jul 3 15:53:38 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thomas Gleixner X-Patchwork-Id: 6716381 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 637C9C05AC for ; Fri, 3 Jul 2015 15:56:49 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 9B9EC20643 for ; Fri, 3 Jul 2015 15:56:48 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id C736B20642 for ; Fri, 3 Jul 2015 15:56:47 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZB3Ig-0001la-PS; Fri, 03 Jul 2015 15:54:50 +0000 Received: from galois.linutronix.de ([2001:470:1f0b:db:abcd:42:0:1]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZB3I0-0001jm-Dd for linux-arm-kernel@lists.infradead.org; Fri, 03 Jul 2015 15:54:08 +0000 Received: from localhost ([127.0.0.1]) by Galois.linutronix.de with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.80) (envelope-from ) id 1ZB3HY-0002S5-HL; Fri, 03 Jul 2015 17:53:40 +0200 Date: Fri, 3 Jul 2015 17:53:38 +0200 (CEST) From: Thomas Gleixner To: Wolfram Sang Subject: Re: Possible regression due to "tick: broadcast: Prevent livelock from event handler" In-Reply-To: <20150703154036.GD19284@katana> Message-ID: References: <20150703024044.GB24695@verge.net.au> <20150703105441.GF1521@katana> <20150703133245.GA19284@katana> <20150703143703.GB19284@katana> <20150703150951.GC19284@katana> <20150703154036.GD19284@katana> User-Agent: Alpine 2.11 (DEB 23 2013-08-11) MIME-Version: 1.0 X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1, SHORTCIRCUIT=-0.0001 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20150703_085408_620004_920139BC X-CRM114-Status: GOOD ( 21.09 ) X-Spam-Score: -4.8 (----) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Geert Uytterhoeven , Kevin Hilman , Magnus Damm , linux-sh@vger.kernel.org, Tyler Baker , linux-kernel@vger.kernel.org, Simon Horman , Borislav Petkov , linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.8 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP On Fri, 3 Jul 2015, Wolfram Sang wrote: > > Ok. One more check please. Does nohz=off on the command line fix/hide > > the issue as well? > > Yes, it does. It boots to the prompt then. So something is fishy with this timer. In your UP setting we don't have any interaction with the broadcast stuff. It's just the single em_sti timer involved. Now looking at the code I notice, that this is one of the overly clever designed compare register based trainwrecks. Can you try the patch below, whether it makes a difference? Thanks, tglx diff --git a/drivers/clocksource/em_sti.c b/drivers/clocksource/em_sti.c index dc3c6ee04aaa..41d8035d294e 100644 --- a/drivers/clocksource/em_sti.c +++ b/drivers/clocksource/em_sti.c @@ -308,7 +308,7 @@ static void em_sti_register_clockevent(struct em_sti_priv *p) dev_info(&p->pdev->dev, "used for clock events\n"); /* Register with dummy 1 Hz value, gets updated in ->set_mode() */ - clockevents_config_and_register(ced, 1, 2, 0xffffffff); + clockevents_config_and_register(ced, 1, 100, 0xffffffff); } static int em_sti_probe(struct platform_device *pdev)