From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: [linux-pm] [PATCH] hibernation should work ok with memory hotplug From: Nigel Cunningham 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 Date: Thu, 06 Nov 2008 13:03:06 +1100 Message-Id: <1225936986.6216.23.camel@nigel-laptop> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: 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 List-ID: 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, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org