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

[Stephen Hemminger <shemminger@xxxxxxxx>]

On Fri, 22 Apr 2005 01:10:25 +0200
Patrick McHardy <kaber@xxxxxxxxx> wrote:

> Stephen Hemminger wrote:
> > So duplication is a no go...
> > Unless there is a different way of accounting for qlen (like a callback).
> 
> Instead of a callback you could store parent pointers in struct Qdisc
> and walk up the tree. One place that would need additional changes to
> cope with qlen changes of more than 1 is HFSC. It uses q.qlen == 1 as
> indication that a leaf qdisc was activated by the last enqueue
> operation. An increment of 2 when q.qlen was 0 before would cause HFSC
> to forget to activate a class.

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++;
}