From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030726AbXD1V0H (ORCPT ); Sat, 28 Apr 2007 17:26:07 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030862AbXD1V0H (ORCPT ); Sat, 28 Apr 2007 17:26:07 -0400 Received: from smtp1.linux-foundation.org ([65.172.181.25]:47922 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030726AbXD1V0E (ORCPT ); Sat, 28 Apr 2007 17:26:04 -0400 Date: Sat, 28 Apr 2007 14:25:17 -0700 (PDT) From: Linus Torvalds To: "Rafael J. Wysocki" cc: Pavel Machek , Nigel Cunningham , Pekka J Enberg , LKML , Oleg Nesterov Subject: Re: Back to the future. In-Reply-To: <200704281950.30405.rjw@sisk.pl> Message-ID: References: <1177567481.5025.211.camel@nigel.suspend2.net> <20070428085000.GA3293@elf.ucw.cz> <200704281950.30405.rjw@sisk.pl> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 28 Apr 2007, Rafael J. Wysocki wrote: > > > > The freezer has *caused* those deadlocks (eg by stopping threads that were > > needed for the suspend writeouts to succeed!), not solved them. > > I can't remember anything like this, but I believe you have a specific test > case in mind. Ehh.. Why do you thik we _have_ that PF_NOFREEZE thing in the first place? Rafael, you really don't know what you're talking about, do you? Just _look_ at them. It's the IO threads etc that shouldn't be frozen, exactly *because* they do IO. You claim that kernel threads shouldn't do IO, but that's the point: if you cannot do IO when snapshotting to disk, here's a damn big clue for you: how do you think that snapshot is going to get written? I *guarantee* you that we've had a lot more problems with threads that should *not* have been frozen than with those hypothetical threads that you think should have been frozen. Linus