Re: [PATCH net-next v2 2/4] eth: mpnic: report per-queue stats

[Jakub Kicinski <kuba@kernel.org>]

On Tue, 13 Oct 2026 09:30:02 -0400 Daniel Zahka wrote:
> > The counter semantics come from "eth: mpnic: count packets, bytes, and
> > drops per ring" earlier in this series. This patch is the one that
> > exposes them as qstats rx-packets and rx-bytes.
> >
> > The later patch "eth: mpnic: count Rx allocation failures" also counts
> > skb build failures in alloc_failed. Those packets still stay in packets
> > and bytes.
> 
> So, the question is whether or not rx-packets, reported both to rtnl
> stats and qstats, should count drops in the driver. Here, drops are
> either running out of shinfo frags, but really just skb allocation
> failure. 
> 
> The docs for rtnl stats strongly suggest an skb allocation failure
> should still be counted for rx-packets.
> 
> The docs for qstats imply the opposite. Especially when xdp is not
> present, which is the case as of this point. Once xdp is introduced,
> though, counting an skb allocation failure in rx-packets becomes
> reasonable by the qstats docs, because xdp runs before the point of skb
> allocation.
> 
> Another option would be reporting rx-packets differently for the two
> APIs. I think this is not desirable, and seems to violate what is in
> the stats.py selftest.
> 
> So, I could either submit a v3, which would just be reverting to v1, or
> take the approach here as is.

The rtnl stats and qstats are supposed to behave the same if maintained
by SW. I should have been clearer in the doc but "XDP is considered the
first layer" was supposed to mean - if you reach the point in the driver
where you'd call an XDP prog - its a successful Rx, whether the XDP prog
is actually attached & called, or is NULL & skipped.

I believe the series is good as is.

Acked-by: Jakub Kicinski <kuba@kernel.org>