Eric Dumazet <eric.duma...@gmail.com> wrote:
> From: Eric Dumazet <eduma...@google.com>
>
> My prior attempt to fix the backlogs of parents failed.
>
> If we return NET_XMIT_CN, our parents wont increase their backlog,
> so our qdisc_tree_reduce_backlog() should take this into account.
[..]
> diff --git a/net/sched/sch_fq_codel.c b/net/sched/sch_fq_codel.c
> index 6883a8971562..c57ec480a2da 100644
> --- a/net/sched/sch_fq_codel.c
> +++ b/net/sched/sch_fq_codel.c
> @@ -240,11 +240,19 @@ static int fq_codel_enqueue(struct sk_buff *skb, struct
> Qdisc *sch)
> q->drop_overlimit += prev_qlen - sch->q.qlen;
> if (memory_limited)
> q->drop_overmemory += prev_qlen - sch->q.qlen;
> - /* As we dropped packet(s), better let upper stack know this */
> - qdisc_tree_reduce_backlog(sch, prev_qlen - sch->q.qlen,
> - prev_backlog - sch->qstats.backlog);
> -
> - return ret == idx ? NET_XMIT_CN : NET_XMIT_SUCCESS;
> + /* As we dropped packet(s), better let upper stack know this.
> + * If we dropped a packet for this flow, return NET_XMIT_CN,
> + * but in this case, our parents wont increase their backlogs.
> + */
> + prev_qlen -= sch->q.qlen;
> + prev_backlog -= sch->qstats.backlog;
> + if (ret == idx) {
> + qdisc_tree_reduce_backlog(sch, prev_qlen - 1,
> + prev_backlog - qdisc_pkt_len(skb));
> + return NET_XMIT_CN;
Is skb still valid here? AFAICS its possible that fq_codel_drop() drops it.
Other than that this looks good, thanks Eric!
