From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Galbraith Subject: Re: [PATCH RT 2/4] Revert "timers: do not raise softirq unconditionally" Date: Thu, 26 Mar 2015 07:01:04 +0100 Message-ID: <1427349664.3497.37.camel@gmail.com> References: <20150317163541.080310081@goodmis.org> <20150317163617.218582800@goodmis.org> <20150317163551.3093b6c2@gandalf.local.home> <1426753029.4168.80.camel@gmail.com> <20150319122611.0d002d48@gandalf.local.home> <550AFC6A.4050901@hp.com> <1426960943.4677.34.camel@gmail.com> <1427085774.3151.7.camel@gmail.com> <55136C2A.60508@hp.com> <1427347391.3497.25.camel@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: Steven Rostedt , linux-kernel@vger.kernel.org, linux-rt-users , Thomas Gleixner , Carsten Emde , Sebastian Andrzej Siewior , John Kacur , Paul Gortmaker To: Thavatchai Makphaibulchoke Return-path: Received: from mail-wi0-f175.google.com ([209.85.212.175]:36837 "EHLO mail-wi0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750843AbbCZGBH (ORCPT ); Thu, 26 Mar 2015 02:01:07 -0400 In-Reply-To: <1427347391.3497.25.camel@gmail.com> Sender: linux-rt-users-owner@vger.kernel.org List-ID: On Thu, 2015-03-26 at 06:23 +0100, Mike Galbraith wrote: > On Wed, 2015-03-25 at 20:17 -0600, Thavatchai Makphaibulchoke wrote: > > > > On 03/22/2015 10:42 PM, Mike Galbraith wrote: > > >> Why can't we just Let swapper be the owner when in irq with no dummy? > > >> > > > > Thanks Mike for the suggestion. That may also work. Unfortunately > > somehow I'm still having a hung problem, which may be related to the > > priority of the interrupt handler task. > > > > >> I have "don't raise timer unconditionally" re-applied, the check for a > > >> running callback bits of my nohz_full fixlet, and the below on top of > > >> that, and all _seems_ well. > > > > > > But not so well on 64 core box. That has nothing to do with hacklet > > > though, re-applying timers-do-not-raise-softirq-unconditionally.patch > > > without thta hangs the 64 core box during boot with no help from me > > > other than to patchlet to let nohz work at all, seems there's another > > > issue lurking there. Hohum. Without 'don't raise..", big box is fine. > > > > > > > If you get your patch to work, I could try my test that was able to > > reproduce the problem consistently. > > If you had "don't raise timer unconditionally" applied, no surprise, my > big box hangs too with or without hacklet. If didn't have it applied, > you don't need the hack. If you had both and rtmutex debugging turned > on, posted version _should_ explode, as it didn't bother to side-step > that bit (et al). Oh, and if you didn't have the below enabled, you'll certainly hang. rt-nohz_full-fix-nohz_full-for-PREEMPT_RT_FULL.patch -Mike