Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754809AbYKFCDX (ORCPT ); Wed, 5 Nov 2008 21:03:23 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752542AbYKFCDP (ORCPT ); Wed, 5 Nov 2008 21:03:15 -0500 Received: from mail.crca.org.au ([67.207.131.56]:45872 "EHLO crca.org.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752334AbYKFCDO (ORCPT ); Wed, 5 Nov 2008 21:03:14 -0500 X-Bogosity: Ham, spamicity=0.000000 Subject: Re: [linux-pm] [PATCH] hibernation should work ok with memory hotplug From: Nigel Cunningham To: KAMEZAWA Hiroyuki Cc: Dave Hansen , Tolentino , Hansen , linux-pm@lists.osdl.org, Matt@smtp1.linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Dave@smtp1.linux-foundation.org, Mel Gorman , Andy@smtp1.linux-foundation.org, Whitcroft , Yasunori Goto , pavel@suse.cz, Andrew Morton In-Reply-To: <20081106095314.8e65f443.kamezawa.hiroyu@jp.fujitsu.com> References: <20081029105956.GA16347@atrey.karlin.mff.cuni.cz> <1225817945.12673.602.camel@nimitz> <20081105093837.e073c373.kamezawa.hiroyu@jp.fujitsu.com> <200811051208.26628.rjw@sisk.pl> <20081106091441.6517c072.kamezawa.hiroyu@jp.fujitsu.com> <1225931281.11514.27.camel@nimitz> <20081106095314.8e65f443.kamezawa.hiroyu@jp.fujitsu.com> Content-Type: text/plain Organization: Christian Reformed Churches of Australia Date: Thu, 06 Nov 2008 13:03:06 +1100 Message-Id: <1225936986.6216.23.camel@nigel-laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.22.3.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1569 Lines: 40 Hi. On Thu, 2008-11-06 at 09:53 +0900, KAMEZAWA Hiroyuki wrote: > On Wed, 05 Nov 2008 16:28:01 -0800 > Dave Hansen wrote: > > > On Thu, 2008-11-06 at 09:14 +0900, KAMEZAWA Hiroyuki wrote: > > > Ok, please consider "when memory hotplug happens." > > > > > > In general, it happens when > > > 1. memory is inserted to slot. > > > 2. the firmware notifes the system to enable already inserted memory. > > > > > > To trigger "1", you have to open cover of server/pc. Do you open pc while the system > > > starts hibernation ? for usual people, no. > > > > You're right, this won't happen very often. We're trying to close a > > theoretical hole that hasn't ever been observed in practice. But, we > > don't exactly leave races in code just because we haven't observed them. > > I think this is a classic race. > > > > If we don't close it now, then someone doing some really weirdo hotplug > > is going to run into it at some point. Who knows what tomorrow's > > hardware/firmware will do? > > > Hmm, people tend to make crazy hardware, oh yes. the pc may fly in the sky with rocket engine. It doesn't even have to be crazy. Just imagine someone bumping a button on the case while plugging in the memory and that button being configured to make the machine hibernate. Regards, Nigel -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/