Commit bb3d0b8b authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

net_sched: sch_fq: properly set sk->sk_pacing_status 



If fq_classify() recycles a struct fq_flow because
a socket structure has been reallocated, we do not
set sk->sk_pacing_status immediately, but later if the
flow becomes detached.

This means that any flow requiring pacing (BBR, or SO_MAX_PACING_RATE)
might fallback to TCP internal pacing, which requires a per-socket
high resolution timer, and therefore more cpu cycles.

Fixes: 218af599 ("tcp: internal implementation for pacing")
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Cc: Soheil Hassas Yeganeh <soheil@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Acked-by: default avatarSoheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 4e55a11a

net/sched/sch_fq.c

+8 −9
Original line number Diff line number Diff line
@@ -301,6 +301,9 @@ static struct fq_flow *fq_classify(struct sk_buff *skb, struct fq_sched_data *q) 
				     f->socket_hash != sk->sk_hash)) {

				f->credit = q->initial_quantum;

				f->socket_hash = sk->sk_hash;

				if (q->rate_enable)

					smp_store_release(&sk->sk_pacing_status,

							  SK_PACING_FQ);

				if (fq_flow_is_throttled(f))

					fq_flow_unset_throttled(q, f);

				f->time_next_packet = 0ULL;
@@ -322,8 +325,12 @@ static struct fq_flow *fq_classify(struct sk_buff *skb, struct fq_sched_data *q) 


	fq_flow_set_detached(f);

	f->sk = sk;

	if (skb->sk == sk)

	if (skb->sk == sk) {

		f->socket_hash = sk->sk_hash;

		if (q->rate_enable)

			smp_store_release(&sk->sk_pacing_status,

					  SK_PACING_FQ);

	}

	f->credit = q->initial_quantum;



	rb_link_node(&f->fq_node, parent, p);
@@ -428,17 +435,9 @@ static int fq_enqueue(struct sk_buff *skb, struct Qdisc *sch, 
	f->qlen++;

	qdisc_qstats_backlog_inc(sch, skb);

	if (fq_flow_is_detached(f)) {

		struct sock *sk = skb->sk;



		fq_flow_add_tail(&q->new_flows, f);

		if (time_after(jiffies, f->age + q->flow_refill_delay))

			f->credit = max_t(u32, f->credit, q->quantum);

		if (sk && q->rate_enable) {

			if (unlikely(smp_load_acquire(&sk->sk_pacing_status) !=

				     SK_PACING_FQ))

				smp_store_release(&sk->sk_pacing_status,

						  SK_PACING_FQ);

		}

		q->inactive_flows--;

	}

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