From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?ISO-8859-1?Q?Nicolas_de_Peslo=FCan?= Subject: Re: IPv6: autoconfiguration and suspend/resume or link down/up Date: Sun, 24 Jul 2011 10:35:58 +0200 Message-ID: <4E2BD96E.4090101@gmail.com> References: <20110719180222.GA7509@midget.suse.cz> <20110722.010628.1678943945721626312.davem@davemloft.net> <20110722092159.GA20722@gondor.apana.org.au> <4E2ADB39.9070409@gmail.com> <20110723152724.GA11028@gondor.apana.org.au> <20110723093743.7c90b78f@nehalam.ftrdhcpuser.net> <20110724001816.GA14051@gondor.apana.org.au> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Stephen Hemminger , David Miller , jbohac@suse.cz, netdev@vger.kernel.org To: Herbert Xu Return-path: Received: from mail-ww0-f42.google.com ([74.125.82.42]:35798 "EHLO mail-ww0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751984Ab1GXIgD (ORCPT ); Sun, 24 Jul 2011 04:36:03 -0400 Received: by wwg11 with SMTP id 11so677589wwg.1 for ; Sun, 24 Jul 2011 01:36:01 -0700 (PDT) In-Reply-To: <20110724001816.GA14051@gondor.apana.org.au> Sender: netdev-owner@vger.kernel.org List-ID: Le 24/07/2011 02:18, Herbert Xu a =E9crit : > On Sat, Jul 23, 2011 at 09:37:43AM -0700, Stephen Hemminger wrote: >> >> Would it be possible to do live migration without dropping carrier >> or setting interface down? > > I think LM uses the same mechanism as suspend and resume so whatever > happens in one case will happen in the other case as well. So we need to distinguish between two kind of link events: 1/ Really having the link goes down then up. This should trigger a rene= gotiation. 2/ Having the system suspend then resume : 2a/ This should trigger link down/link up events to force a renegotiati= on, for normal suspend/resume=20 where the network might have changed between suspend and resume. 2/ This should *not* trigger link down/link up events to avoid a renego= tiation (for live migration)=20 because it is assumed that the network didn't change while suspended. Can't we allow the user to set a global "link-down-link-up-timeout" and= only force a renegotiation=20 if the time between link down and link up events is longer than this ti= meout? Normal user would set=20 this timeout close to 0 (default value). Live migration user would set = this timeout to about twice=20 the time it normally takes to do a live migration. That way, in a VM en= vironment, if the=20 suspend/resume cycle happens to take far more than a normal live migrat= ion time, the kernel would=20 renegotiate, which sounds reasonable, from my point of view. Does this make sense? Nicolas.