From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932482AbcLZQk1 (ORCPT ); Mon, 26 Dec 2016 11:40:27 -0500 Received: from mail-wm0-f65.google.com ([74.125.82.65]:33043 "EHLO mail-wm0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754425AbcLZQkZ (ORCPT ); Mon, 26 Dec 2016 11:40:25 -0500 Date: Mon, 26 Dec 2016 17:40:19 +0100 From: Frederic Weisbecker To: Rik van Riel Cc: Thomas Gleixner , LKML , Peter Zijlstra , James Hartsock , Ingo Molnar Subject: Re: [PATCH] nohz: Fix collision between tick and other hrtimers Message-ID: <20161226164015.GA2375@lerouge> References: <1482596100-16494-1-git-send-email-fweisbec@gmail.com> <1482721017.11006.83.camel@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1482721017.11006.83.camel@redhat.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Dec 25, 2016 at 09:56:57PM -0500, Rik van Riel wrote: > On Sat, 2016-12-24 at 17:15 +0100, Frederic Weisbecker wrote: > > When the tick is stopped and an interrupt occurs afterward, we check > > on > > that interrupt exit if the next tick needs to be rescheduled. If it > > doesn't need any update, we don't want to do anything. > > > > In order to check if the tick needs an update, we compare it against > > the > > clockevent device deadline. Now that's a problem because the > > clockevent > > device is at a lower level than the tick itself if it is implemented > > on top of hrtimer. > > Ohhhhh, good find. That is one subtle bug. Oh yeah, it took me several month to debug that one :-) ! > > Acked-by: Rik van Riel Thanks! > > -- > All Rights Reversed.