Re: [net-next PATCH 2/5] net: Call sk_mark_napi_id() in the ACK receive path

Eric Dumazet
2017-03-16T22:04:58Z

On Thu, 2017-03-16 at 11:32 -0700, Alexander Duyck wrote:
> From: Sridhar Samudrala <sridhar.samudrala@intel.com>
>
> Call sk_mark_napi_id() in the ACK receive path of a TCP_NEW_SYN_RECV
> socket, so that sk->napi_id is set even if the socket hasn't yet received
> any data. With this change we should be able to start busy polling
> slightly earlier.
>
> Signed-off-by: Sridhar Samudrala <sridhar.samudrala@intel.com>
> Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
> ---
> net/ipv4/tcp_ipv4.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
> index 08d870e45658..b86002a296f1 100644
> --- a/net/ipv4/tcp_ipv4.c
> +++ b/net/ipv4/tcp_ipv4.c
> @@ -1687,6 +1687,7 @@ int tcp_v4_rcv(struct sk_buff *skb)
> tcp_v4_send_reset(nsk, skb);
> goto discard_and_relse;
> } else {
> + sk_mark_napi_id(nsk, skb);
> sock_put(sk);
> return 0;
> }
>

Seems good, but what about IPv6 ?

Frankly this calls for the sk_mark_napi_id() being done in
tcp_child_process() instead of its four callers.