On Sat, Jun 20, 2020 at 12:42:36PM +0200, Kal Cutter Conley wrote: > On Thu, Jun 18, 2020 at 5:23 PM Jonathan Lemon <jonathan.lemon@xxxxxxxxx> wrote: > > > > On Sun, Jun 14, 2020 at 10:55:30AM +0200, Kal Cutter Conley wrote: > > > Hi Saeed, > > > Thanks for explaining the reasoning behind the special mlx5 queue > > > numbering with XDP zerocopy. > > > > > > We have a process using AF_XDP that also shares the network interface > > > with other processes on the system. ethtool rx flow classification > > > rules are used to route the traffic to the appropriate XSK queue > > > N..(2N-1). The issue is these queues are only valid as long they are > > > active (as far as I can tell). This means if my AF_XDP process dies > > > other processes no longer receive ingress traffic routed over queues > > > N..(2N-1) even though my XDP program is still loaded and would happily > > > always return XDP_PASS. Other drivers do not have this usability issue > > > because they use queues that are always valid. Is there a simple > > > workaround for this issue? It seems to me queues N..(2N-1) should > > > simply map to 0..(N-1) when they are not active? > > > > If your XDP program returns XDP_PASS, the packet should be delivered to > > the xsk socket. If the application isn't running, where would it go? > > > > I do agree that the usability of this can be improved. What if the flow > > rules are inserted and removed along with queue creatioin/destruction? > > I think I misunderstood your suggestion here. Do you mean the rules > should be inserted / removed on the hardware level but still show in > ethtool even if they are not active in the hardware? In this case the > rules always occupy a "location" but just never apply if the > respective queues are not "enabled". I think this would be the best > possible solution. No, that wasn't what I was suggesting. I would think that having ethtool return something that isn't true woulld be really confusing - either the rules are enabled and active, or they should not be there. I was thinking more along the lines of having the flow rules inserted and removed when the queue is created/destroyed, so the steering rule is a property of the queue itself rather than maintained externally through ethtool. -- Jonathan
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