From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754113AbXD1TKu (ORCPT ); Sat, 28 Apr 2007 15:10:50 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754090AbXD1TKu (ORCPT ); Sat, 28 Apr 2007 15:10:50 -0400 Received: from ogre.sisk.pl ([217.79.144.158]:34502 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754784AbXD1TKs (ORCPT ); Sat, 28 Apr 2007 15:10:48 -0400 From: "Rafael J. Wysocki" To: David Lang Subject: Re: Back to the future. Date: Sat, 28 Apr 2007 21:14:48 +0200 User-Agent: KMail/1.9.5 Cc: Pavel Machek , Linus Torvalds , Nigel Cunningham , Pekka J Enberg , LKML , Oleg Nesterov References: <1177567481.5025.211.camel@nigel.suspend2.net> <20070428085000.GA3293@elf.ucw.cz> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200704282114.49815.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Saturday, 28 April 2007 20:32, David Lang wrote: > On Sat, 28 Apr 2007, Pavel Machek wrote: > > >> > >> We freeze user space processes for the reasons that you have quoted above. > >> > >> Why we freeze kernel threads in there too is a good question, but not for me to > >> answer. I don't know. Pavel should know, I think. > > > > We do not want kernel threads running: > > > > a) they may hold some locks and deadlock suspend > > > > b) they may do some writes to disk, leading to corruption > > > > We could solve a) by carefully auditing suspend lock usage to make > > sure deadlocks are impossible even with kernel threads running. > > remember that we are doing suspend-to-disk, after we do the snapshot we will be > doing a shutdown. that should simplify the locking issues That's assuming that we won't need to cancel the hibernation. Greetings, Rafael