On Wed, 6 Jun 2018 14:54:04 -0700 "Samudrala, Sridhar" <sridhar.samudr...@intel.com> wrote:
> On 6/6/2018 2:24 PM, Stephen Hemminger wrote: > > On Wed, 6 Jun 2018 15:30:27 +0300 > > "Michael S. Tsirkin" <m...@redhat.com> wrote: > > > >> On Wed, Jun 06, 2018 at 09:25:12AM +0200, Jiri Pirko wrote: > >>> Tue, Jun 05, 2018 at 05:42:31AM CEST, step...@networkplumber.org wrote: > >>>> The net failover should be a simple library, not a virtual > >>>> object with function callbacks (see callback hell). > >>> Why just a library? It should do a common things. I think it should be a > >>> virtual object. Looks like your patch again splits the common > >>> functionality into multiple drivers. That is kind of backwards attitude. > >>> I don't get it. We should rather focus on fixing the mess the > >>> introduction of netvsc-bonding caused and switch netvsc to 3-netdev > >>> model. > >> So it seems that at least one benefit for netvsc would be better > >> handling of renames. > >> > >> Question is how can this change to 3-netdev happen? Stephen is > >> concerned about risk of breaking some userspace. > >> > >> Stephen, this seems to be the usecase that IFF_HIDDEN was trying to > >> address, and you said then "why not use existing network namespaces > >> rather than inventing a new abstraction". So how about it then? Do you > >> want to find a way to use namespaces to hide the PV device for netvsc > >> compatibility? > >> > > Netvsc can't work with 3 dev model. MS has worked with enough distro's and > > startups that all demand eth0 always be present. And VF may come and go. > > After this history, there is a strong motivation not to change how kernel > > behaves. Switching to 3 device model would be perceived as breaking > > existing userspace. > > I think it should be possible for netvsc to work with 3 dev model if the only > requirement is that eth0 will always be present. With net_failover, you will > see eth0 and eth0nsby OR with older distros eth0 and eth1. It may be an issue > if somehow there is userspace requirement that there can be only 2 netdevs, > not 3 > when VF is plugged. > > eth0 will be the net_failover device and eth0nsby/eth1 will be the netvsc > device > and the IP address gets configured on eth0. Will this be an issue? DPDK drivers in 18.05 depend on 2 device model. Yes it is a bit of mess but that is the way it is.
