From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Hutchings Subject: Re: [BUG?] bonding, slave selection, carrier loss, etc. Date: Sat, 11 Feb 2012 18:52:51 +0000 Message-ID: <1328986371.325.7.camel@deadeye> References: <49CD5B93.7010407@nortel.com> <31087.1238198438@death.nxdomain.ibm.com> <4F35AC78.3010907@genband.com> <28766.1328925233@death.nxdomain> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: Chris Friesen , , netdev To: Jay Vosburgh Return-path: Received: from mail.solarflare.com ([216.237.3.220]:7883 "EHLO ocex02.SolarFlarecom.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754471Ab2BKSwv (ORCPT ); Sat, 11 Feb 2012 13:52:51 -0500 In-Reply-To: <28766.1328925233@death.nxdomain> Sender: netdev-owner@vger.kernel.org List-ID: On Fri, 2012-02-10 at 17:53 -0800, Jay Vosburgh wrote: > Chris Friesen wrote: > > >I'm resurrecting an ancient discussion I had with Jay, because I think > >the issue described below is still present and the code he talked about > >submitting to close it doesn't appear to have ever gone in. > > Yah, I never got it to work quite right; I don't remember > exactly why. > > >Basically in active/backup mode with mii monitoring there is a window > >between the active slave device losing carrier and calling > >netif_carrier_off() and the miimon code actually detecting the loss of > >the carrier and selecting a new active slave. > > > >The best solution would be for bonding to just register for notification > >of the link going down. Presumably most drivers should be doing that > >properly by now, and for devices that get interrupt-driven notification > >of link status changes this would allow the bonding code to react much > >quicker. > > A quick look at some drivers shows that at least acenic still > doesn't do netif_carrier_off, so converting entirely to a notifier-based > failover mechanism would break drivers that work today. [...] It might be worth having some sort of feature flag (in priv_flags) that indicates whether the driver updates the link state. Alternately, disable polling of a device once you see a notification. Ben. -- Ben Hutchings, Staff Engineer, Solarflare Not speaking for my employer; that's the marketing department's job. They asked us to note that Solarflare product names are trademarked.