Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932505AbcCBAQN (ORCPT ); Tue, 1 Mar 2016 19:16:13 -0500 Received: from mail177-1.suw61.mandrillapp.com ([198.2.177.1]:21464 "EHLO mail177-1.suw61.mandrillapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932432AbcCAX6J (ORCPT ); Tue, 1 Mar 2016 18:58:09 -0500 From: Greg Kroah-Hartman Subject: [PATCH 4.4 272/342] tick/nohz: Set the correct expiry when switching to nohz/lowres mode X-Mailer: git-send-email 2.7.2 To: Cc: Greg Kroah-Hartman , , Wanpeng Li , Peter Zijlstra , Frederic Weisbecker , Thomas Gleixner Message-Id: <20160301234536.701613740@linuxfoundation.org> In-Reply-To: <20160301234527.990448862@linuxfoundation.org> References: <20160301234527.990448862@linuxfoundation.org> X-Report-Abuse: Please forward a copy of this message, including all headers, to abuse@mandrill.com X-Report-Abuse: You can also report abuse here: http://mandrillapp.com/contact/abuse?id=30481620.dd3d937c053a4237b9217c8b33a84652 X-Mandrill-User: md_30481620 Date: Tue, 01 Mar 2016 23:55:21 +0000 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1518 Lines: 40 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Wanpeng Li commit 1ca8ec532fc2d986f1f4a319857bb18e0c9739b4 upstream. commit 0ff53d096422 sets the next tick interrupt to the last jiffies update, i.e. in the past, because the forward operation is invoked before the set operation. There is no resulting damage (yet), but we get an extra pointless tick interrupt. Revert the order so we get the next tick interrupt in the future. Fixes: commit 0ff53d096422 "tick: sched: Force tick interrupt and get rid of softirq magic" Signed-off-by: Wanpeng Li Cc: Peter Zijlstra Cc: Frederic Weisbecker Link: http://lkml.kernel.org/r/1453893967-3458-1-git-send-email-wanpeng.li@hotmail.com Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman --- kernel/time/tick-sched.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -977,9 +977,9 @@ static void tick_nohz_switch_to_nohz(voi /* Get the next period */ next = tick_init_jiffy_update(); - hrtimer_forward_now(&ts->sched_timer, tick_period); hrtimer_set_expires(&ts->sched_timer, next); - tick_program_event(next, 1); + hrtimer_forward_now(&ts->sched_timer, tick_period); + tick_program_event(hrtimer_get_expires(&ts->sched_timer), 1); tick_nohz_activate(ts, NOHZ_MODE_LOWRES); }