From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758236AbXGEG6Q (ORCPT ); Thu, 5 Jul 2007 02:58:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756572AbXGEG6E (ORCPT ); Thu, 5 Jul 2007 02:58:04 -0400 Received: from smtp-out001.kontent.com ([81.88.40.215]:50860 "EHLO smtp-out.kontent.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756354AbXGEG6D convert rfc822-to-8bit (ORCPT ); Thu, 5 Jul 2007 02:58:03 -0400 From: Oliver Neukum To: Paul Mackerras Subject: Re: [linux-pm] Re: [PATCH] Remove process freezer from suspend to RAM pathway Date: Thu, 5 Jul 2007 08:58:03 +0200 User-Agent: KMail/1.9.7 Cc: Alan Stern , Johannes Berg , "Rafael J. Wysocki" , Linux-pm mailing list , Kernel development list , Pavel Machek , Matthew Garrett , Benjamin Herrenschmidt References: <18059.10554.955290.148535@cargo.ozlabs.ibm.com> <18060.14856.824473.325660@cargo.ozlabs.ibm.com> In-Reply-To: <18060.14856.824473.325660@cargo.ozlabs.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 8BIT Content-Disposition: inline Message-Id: <200707050858.03638.oliver@neukum.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Am Donnerstag, 5. Juli 2007 schrieb Paul Mackerras: > > I have discussed the benefits elsewhere.  As for the deadlocks -- do > > you still observe them if you use the version of the freezer which > > doesn't freeze kernel threads? > > In general the only way to guarantee there are no deadlocks is to > construct the graph of dependencies between tasks.  Those dependencies > are not in practice observable from outside the tasks, so it is > virtually impossible to construct the graph. In which way can user space tasks depend on each other in a way that allows a them members of that cycle to be in uninterruptible sleep? Regards Oliver