From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Re: [PATCH RFC 2/2] veth: propagate bridge GSO to peer Date: Mon, 27 Nov 2017 13:15:02 -0800 Message-ID: <20171127131502.1fbfaa66@xeon-e3> References: <20171126181749.19288-1-sthemmin@microsoft.com> <20171126181749.19288-3-sthemmin@microsoft.com> <20171126230725.1fcc3b51@xeon-e3> <20171127201419.GA79@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: dsahern@gmail.com, davem@davemloft.net, netdev@vger.kernel.org, sthemmin@microsoft.com To: Solio Sarabia Return-path: Received: from mail-pl0-f45.google.com ([209.85.160.45]:36651 "EHLO mail-pl0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751601AbdK0VPK (ORCPT ); Mon, 27 Nov 2017 16:15:10 -0500 Received: by mail-pl0-f45.google.com with SMTP id b12so9247258plm.3 for ; Mon, 27 Nov 2017 13:15:10 -0800 (PST) In-Reply-To: <20171127201419.GA79@intel.com> Sender: netdev-owner@vger.kernel.org List-ID: On Mon, 27 Nov 2017 12:14:19 -0800 Solio Sarabia wrote: > On Sun, Nov 26, 2017 at 11:07:25PM -0800, Stephen Hemminger wrote: > > On Sun, 26 Nov 2017 20:13:39 -0700 > > David Ahern wrote: > > > > > On 11/26/17 11:17 AM, Stephen Hemminger wrote: > > > > This allows veth device in containers to see the GSO maximum > > > > settings of the actual device being used for output. > > > > > > veth devices can be added to a VRF instead of a bridge, and I do not > > > believe the gso propagation works for L3 master devices. > > > > > > From a quick grep, team devices do not appear to handle gso changes either. > > > > This code should still work correctly, but no optimization would happen. > > The gso_max_size of the VRF or team will > > still be GSO_MAX_SIZE so there would be no change. If VRF or Team ever got smart > > enough to handle GSO limits, then the algorithm would handle it. > > This patch propagates gso value from bridge to its veth endpoints. > However, since bridge is never aware of the GSO limit from underlying > interfaces, bridge/veth still have larger GSO size. > > In the docker case, bridge is not linked directly to physical or > synthetic interfaces; it relies on iptables to decide which interface to > forward packets to. So for the docker case, then direct control of GSO values via netlink (ie ip link set) seems like the better solution.