On Tue, 5 Jun 2018 16:52:22 -0700 "Samudrala, Sridhar" <sridhar.samudr...@intel.com> wrote:
> On 6/5/2018 2:52 PM, Stephen Hemminger wrote: > > On Tue, 5 Jun 2018 22:38:43 +0300 > > "Michael S. Tsirkin" <m...@redhat.com> wrote: > > > >>> See: > >>> https://patchwork.ozlabs.org/patch/851711/ > >> Let me try to summarize that: > >> > >> You wanted to speed up the delayed link up. You had an idea to > >> additionally take link up when userspace renames the interface (standby > >> one which is also the failover for netvsc). > >> > >> But userspace might not do any renames, in which case there will > >> still be the delay, and so this never got applied. > >> > >> Is this a good summary? > >> > >> Davem said delay should go away completely as it's not robust, and I > >> think I agree. So I don't think we should make all failover users use > >> delay. IIUC failover kept a delay option especially for netvsc to > >> minimize the surprise factor. Hopefully we can come up with > >> something more robust and drop that option completely. > > The timeout was the original solution to how to complete setup after > > userspace has had a chance to rename the device. Unfortunately, the whole > > network > > device initialization (cooperation with udev and userspace) is a a mess > > because > > there is no well defined specification, and there are multiple ways > > userspace > > does this in old and new distributions. The timeout has its own issues > > (how long, handling errors during that window, what if userspace modifies > > other > > device state); and open to finding a better solution. > > > > My point was that if name change can not be relied on (or used) by netvsc, > > then we can't allow it for net_failover either. > > I think the push back was with the usage of the delay, not bringing up the > primary/standby > device in the name change event handler. > Can't netvsc use this mechanism instead of depending on the delay? > > The patch that was rejected for netvsc was about using name change. Also, you can't depend on name change; you still need a timer. Not all distributions change name of devices. Or user has blocked that by udev rules.
