On Wed, 2016-08-17 at 12:33 -0700, John Fastabend wrote:
> diff --git a/net/core/dev.c b/net/core/dev.c
> index 4ce07dc..5db395d 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -3076,6 +3076,26 @@ static inline int __dev_xmit_skb(struct sk_buff *skb,
> struct Qdisc *q,
> int rc;
>
> qdisc_calculate_pkt_len(skb, q);
> +
> + if (q->flags & TCQ_F_NOLOCK) {
> + if (unlikely(test_bit(__QDISC_STATE_DEACTIVATED, &q->state))) {
> + __qdisc_drop(skb, &to_free);
> + rc = NET_XMIT_DROP;
> + } else if ((q->flags & TCQ_F_CAN_BYPASS) && !qdisc_qlen(q)) {
For a lockless qdisc, do you believe TCQ_F_CAN_BYPASS is still a gain ?
Also !qdisc_qlen(q) looks racy anyway ?
> + qdisc_bstats_cpu_update(q, skb);
> + if (sch_direct_xmit(skb, q, dev, txq, root_lock, true))
> + __qdisc_run(q);
> + rc = NET_XMIT_SUCCESS;
> + } else {
> + rc = q->enqueue(skb, q, &to_free) & NET_XMIT_MASK;
> + __qdisc_run(q);
> + }
> +
> + if (unlikely(to_free))
> + kfree_skb_list(to_free);
> + return rc;
> + }
> +
