Re: [PATCH RFC net-next 4/4] net: allow busy connected flows to switch tx queues

[Paolo Abeni <pabeni@redhat.com>]

On 10/8/25 12:46 PM, Eric Dumazet wrote:
> This is a followup of commit 726e9e8b94b9 ("tcp: refine
> skb->ooo_okay setting") and to the prior commit in this series
> ("net: control skb->ooo_okay from skb_set_owner_w()")
> 
> skb->ooo_okay might never be set for bulk flows that always
> have at least one skb in a qdisc queue of NIC queue,
> especially if TX completion is delayed because of a stressed cpu.
> 
> The so-called "strange attractors" has caused many performance
> issues, we need to do better.

I must admit my ignorance about the topic, do you have any reference handy?

> @@ -1984,6 +1985,14 @@ static inline int sk_receive_skb(struct sock *sk, struct sk_buff *skb,
>  	return __sk_receive_skb(sk, skb, nested, 1, true);
>  }
>  
> +/* This helper checks if a socket is a full socket,
> + * ie _not_ a timewait or request socket.
> + */
> +static inline bool sk_fullsock(const struct sock *sk)
> +{
> +	return (1 << sk->sk_state) & ~(TCPF_TIME_WAIT | TCPF_NEW_SYN_RECV);
> +}
> +

I'm possibly low on coffee, but it looks like it's not needed to move
around sk_fullsock() ?!? possibly sk_tx_queue_get() remained inline in a
previous version of the patch?

Thanks,

Paolo