From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759427AbZJMKhq (ORCPT ); Tue, 13 Oct 2009 06:37:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758483AbZJMKhq (ORCPT ); Tue, 13 Oct 2009 06:37:46 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:49756 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756510AbZJMKhp (ORCPT ); Tue, 13 Oct 2009 06:37:45 -0400 Date: Tue, 13 Oct 2009 12:37:03 +0200 From: Ingo Molnar To: Jia Zhang , Thomas Gleixner , Peter Zijlstra Cc: linux-kernel@vger.kernel.org Subject: Re: [PATCH] softlockup: keep current softlockup period before touching timestamp Message-ID: <20091013103703.GC3915@elte.hu> References: <4ABEFCFE.3080500@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4ABEFCFE.3080500@gmail.com> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.5 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Jia Zhang wrote: > From: Jia Zhang > > Imaging such a scenario, softlockup deadline is 60s and a softirq runs > at most 65s. Assume that currently that softirq runs 50s. At this > moment, issue a "echo 40 > /proc/sys/kernel/softlockup_thresh" and > thus lead to recounting the timeout. The remaining time for that > softirq is 15s less than new threshold 40s, which means the warning > will be depressed after 15s. It is not what we expected because > softlockup actually feeds 100s(old+new) for that softirq. To fix this > problem, softlockup should keep current softlockup period before > touching timestamp. > > Signed-off-by: Jia Zhang > --- > include/linux/sched.h | 5 +---- > kernel/softlockup.c | 26 ++++++++++++++------------ > kernel/sysctl.c | 2 +- > 3 files changed, 16 insertions(+), 17 deletions(-) your patch does not apply to the latest kernel - mind redoing it against latest -tip: http://people.redhat.com/mingo/tip.git/README also please re-post the other patch of yours as well, the "allow checking for remote CPUs" - that too looks like a worthwile improvement. Thanks, Ingo