From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932753AbXCKVuJ (ORCPT ); Sun, 11 Mar 2007 17:50:09 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932849AbXCKVuI (ORCPT ); Sun, 11 Mar 2007 17:50:08 -0400 Received: from www.osadl.org ([213.239.205.134]:33061 "EHLO mail.tglx.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932753AbXCKVuH (ORCPT ); Sun, 11 Mar 2007 17:50:07 -0400 Subject: Re: SwSusp to disk doesn't work - Try 2 From: Thomas Gleixner Reply-To: tglx@linutronix.de To: "Rafael J. Wysocki" Cc: Milan Broz , Andrew Morton , Thomas Meyer , linux-kernel@vger.kernel.org, Pavel Machek In-Reply-To: <200703112209.53665.rjw@sisk.pl> References: <45F44599.3060508@m3y3r.de> <45F46660.4010102@m3y3r.de> <45F46D33.1050808@redhat.com> <200703112209.53665.rjw@sisk.pl> Content-Type: text/plain Date: Sun, 11 Mar 2007 22:56:35 +0100 Message-Id: <1173650195.13341.11.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.6.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 2007-03-11 at 22:09 +0100, Rafael J. Wysocki wrote: > > >>>>> update_sched_domains > > >>>>> detach_destroy_domains > > >>>>> [waits here] --> synchronize_sched (==synchronize_rcu) > > >>>>> > > >>>> Well, I think the call to wait_for_completion() does not return, probably > > >>>> because the task supposed to complete the completion is frozen at this > > >>>> point. Can you please try to confirm that it gets stuck on > > >>>> wait_for_completion() in synchronize_rcu()? > > >>>> > > >>> Yes, it's in wait_for_completion() in synchronize_rcu(). > > >>> As noted in some previous mail, it will wake up after > > >>> event - key press etc. > > >>> > > >>> Patch in http://lkml.org/lkml/2007/3/7/255 solves different problem. > > >>> I added it to my quilt and applied anyway -> no change. > > >>> > > >> Does the problem go away if NO_HZ is unset? > > >> > > > > > > i tried to boot with nohz=off, but the problem did persist. > > > > Hmmmm, both variants (nohz=off or recompiled kernel without NO_HZ) works for me. > > Definitely something strange is going on here. > > I think we need an advice from someone who knows the RCU internals. RCU synchronization depends on the timer interrupt. Which kernel version are you guys talking about ? tglx