Re: netfront/netback multiqueue exhausting grants

[Ian Campbell <ian.campbell@citrix.com>]

On Thu, 2016-01-21 at 10:25 +0000, Wei Liu wrote:
> On Thu, Jan 21, 2016 at 10:12:27AM +0000, Ian Campbell wrote:
> [...]
> > > I've asked the reporter to send logs for the 4.4 case to xen-devel.
> > 
> > User confirmed[0] that 4.4 is actually OK.
> > 
> > Did someone request stable backports yet, or shall I do so?
> > 
> 
> I vaguely remember we requested backport for relevant patches long time
> ago, but I admit I have lost track. So it wouldn't hurt if you do it
> again.

So I think we'd be looking for:

32a8440 xen-netfront: respect user provided max_queues
4c82ac3 xen-netback: respect user provided max_queues
ca88ea1 xen-netfront: update num_queues to real created

which certainly resolves things such that the workarounds work, and I think
will also fix the default case such that it works with up to 32 vcpus
(although it will consume all the grants and only get 31/32 queues).

Does that sound correct?

As Annie said, we may still want to consider what a sensible default max
queues would be.

Ian.