From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Hutchings Subject: Re: [PATCH] bonding:update speed/duplex for NETDEV_CHANGE Date: Mon, 31 Oct 2011 22:41:39 +0000 Message-ID: <1320100899.2735.19.camel@bwh-desktop> References: <4EAE0D9A.9060408@gmail.com> <1320084906.2735.9.camel@bwh-desktop> <14973.1320093129@death> <1320094108.2735.15.camel@bwh-desktop> <16441.1320096188@death> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: Weiping Pan , , , To: Jay Vosburgh Return-path: In-Reply-To: <16441.1320096188@death> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Mon, 2011-10-31 at 14:23 -0700, Jay Vosburgh wrote: > Ben Hutchings wrote: > > >On Mon, 2011-10-31 at 13:32 -0700, Jay Vosburgh wrote: > >[...] > >> This particular case arises only during enslavement. The call > >> to bond_update_speed_duplex call has failed, but the device is marked by > >> bonding to be up. Bonding complains that the device isn't down, but it > >> cannot get speed and duplex, and therefore is assuming them to be > >> 100/Full. > >> > >> The catch is that this happens only for the ARP monitor, because > >> it initially presumes a slave to be up regardless of actual carrier > >> state (for historical reasons related to very old 10 or 10/100 drivers, > >> prior to the introduction of netif_carrier_*). > > > >Right, I gathered that. Is there any reason to use the ARP monitor when > >all slaves support link state notification? Maybe the bonding > >documentation should recommend miimon in section 7, not just in section > >2. > > The ARP monitor can validate that traffic actually flows from > the slave to some destination in the switch domain (and back), so, for > example, it's useful in cases that multiple switch hops exist between > the host and the local router. A link failure in the middle of the path > won't affect carrier on the local device, but still may cause a > communications break. Then the ARP monitor should gracefully handle the case where a new slave has link down, as proposed. 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.