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From: "Nicolas de Pesloüan" <nicolas.2p.debian@gmail.com>
To: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Stephen Hemminger <shemminger@vyatta.com>,
	David Miller <davem@davemloft.net>,
	jbohac@suse.cz, netdev@vger.kernel.org
Subject: Re: IPv6: autoconfiguration and suspend/resume or link down/up
Date: Sun, 24 Jul 2011 10:35:58 +0200	[thread overview]
Message-ID: <4E2BD96E.4090101@gmail.com> (raw)
In-Reply-To: <20110724001816.GA14051@gondor.apana.org.au>

Le 24/07/2011 02:18, Herbert Xu a écrit :
> 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 renegotiation.

2/ Having the system suspend then resume :
2a/ This should trigger link down/link up events to force a renegotiation, for normal suspend/resume 
where the network might have changed between suspend and resume.
2/ This should *not* trigger link down/link up events to avoid a renegotiation (for live migration) 
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 
if the time between link down and link up events is longer than this timeout? Normal user would set 
this timeout close to 0 (default value). Live migration user would set this timeout to about twice 
the time it normally takes to do a live migration. That way, in a VM environment, if the 
suspend/resume cycle happens to take far more than a normal live migration time, the kernel would 
renegotiate, which sounds reasonable, from my point of view.

Does this make sense?

	Nicolas.

  reply	other threads:[~2011-07-24  8:36 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-07-19 18:02 IPv6: autoconfiguration and suspend/resume or link down/up Jiri Bohac
2011-07-20 16:15 ` Stephen Hemminger
2011-07-20 16:29   ` Jiri Bohac
2011-07-20 16:21 ` Dan Williams
2011-07-20 16:36   ` Jiri Bohac
2011-07-21  5:30     ` Dan Williams
2011-07-21 16:35       ` Dan Williams
2011-07-21 19:44         ` Stephen Hemminger
2011-07-22  8:06 ` David Miller
2011-07-22  9:21   ` Herbert Xu
2011-07-23 14:31     ` Nicolas de Pesloüan
2011-07-23 15:27       ` Herbert Xu
2011-07-23 16:37         ` Stephen Hemminger
2011-07-24  0:18           ` Herbert Xu
2011-07-24  8:35             ` Nicolas de Pesloüan [this message]
2011-07-25  3:26               ` Stephen Hemminger
2011-07-25  3:46                 ` Herbert Xu
2011-07-27 19:48   ` Dan Williams
  -- strict thread matches above, loose matches on Subject: below --
2011-07-19 19:42 Stephen Hemminger
2011-07-26  5:16 ` Anirban Chakraborty
2011-07-25 16:55 Stephen Hemminger

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