On Wed, Jun 6, 2018 at 3:25 PM, Stephen Hemminger <step...@networkplumber.org> wrote: > 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.
Why would DPDK care what we do in the kernel? Isn't it just slapping vfio-pci on the netdevs it sees?