Re: [PATCH] netem: account for packets in delayed queue in qlen

[Patrick McHardy <kaber@xxxxxxxxx>]

Stephen Hemminger wrote:
> I'm thinking of changing enqueue (and maybe later dequeue) API to decouple
> the qlen assumption.
>
> Either:
>         rc = qdisc->enqueue(skb, qdisc, &my->qlen)
> or add NET_XMIT_DUPPED
>         rc = qdisc->enqueue(skb, qdisc);
>         if (rc < NET_XMIT_SUCCESS) {
>                 ++my->dropped;
>         } else {
>                 my->qlen++;
>                 if (rc == NET_XMIT_DUPPED)
>                         my->qlen++;
> }
To be frank, I don't like either one. Both have the same problem
wrt. HFSC, the first solution requires changes all over the place,
the second one is unflexible and also requires lots of changes. I
don't see what could benefit from this API change besides netem,
so I'd vote to go with my proposed solution: store the parent
pointers in struct Qdisc, add code to walk up the tree and adjust
the qlen to netem, and fix up HFSC.

Regards
Patrick