Eric Dumazet <eric.duma...@gmail.com> wrote:
> > diff --git a/net/sched/sch_hfsc.c b/net/sched/sch_hfsc.c
> > index d783d7c..0854be3 100644
> > --- a/net/sched/sch_hfsc.c
> > +++ b/net/sched/sch_hfsc.c
> > @@ -1583,6 +1583,7 @@ hfsc_enqueue(struct sk_buff *skb, struct Qdisc *sch)
> > {
> > struct hfsc_class *cl;
> > int uninitialized_var(err);
> > + unsigned int qlen;
> >
> > cl = hfsc_classify(skb, sch, &err);
> > if (cl == NULL) {
> > @@ -1592,6 +1593,7 @@ hfsc_enqueue(struct sk_buff *skb, struct Qdisc *sch)
> > return err;
> > }
> >
> > + qlen = cl->qdisc->q.qlen;
> > err = qdisc_enqueue(skb, cl->qdisc);
> > if (unlikely(err != NET_XMIT_SUCCESS)) {
> > if (net_xmit_drop_count(err)) {
> > @@ -1601,7 +1603,7 @@ hfsc_enqueue(struct sk_buff *skb, struct Qdisc *sch)
> > return err;
> > }
> >
> > - if (cl->qdisc->q.qlen == 1)
> > + if (qlen == 0)
> > set_active(cl, qdisc_pkt_len(skb));
> >
> > sch->q.qlen++;
>
> Well, I am not sure HFSC can deal with non work conserving qdisc
> anyway ?
As long as child qdisc dequeue() returns an skb if qlen > 0 it should
work.
> Call to set_active(cl, qdisc_pkt_len(skb)); would tell you that HFSC
> does not expect another packet than @skb being the next dequeued one.
Good point. I'll look into it in more detail but AFAIU this "only"
means we might overshoot a defined realtime/deadline criterion,
I don't (yet) see how it could explain Miroslavs bug report.
> If you want to make HFSC generic, you would need a lot more changes.
Could you elaborate?
I'm not interested in e.g. tbf leaves (makes no sense to me), but I
think it should play nice with netem, sfq, codel, fq_codel, fq, ...
I don't see any problems with fq_codel + hfsc unless I deliberately
misconfigure fq_codel (setting extremely low mem limit, e.g. 32kbyte).
