Re: [PATCH v4 net-next 2/4] tcp: add TCP support for low latency receive poll.

Ben Hutchings
2013-05-21T17:30:24Z

On Tue, 2013-05-21 at 17:27 +0300, Eliezer Tamir wrote:
> adds busy-poll support for TCP.
>
> Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
> Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
> Tested-by: Willem de Bruijn <willemb@google.com>
> Signed-off-by: Eliezer Tamir <eliezer.tamir@linux.intel.com>
> ---
>
> net/ipv4/tcp.c | 9 +++++++++
> net/ipv4/tcp_input.c | 4 ++++
> 2 files changed, 13 insertions(+), 0 deletions(-)
>
> diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
> index dcb116d..b9cc512 100644
> --- a/net/ipv4/tcp.c
> +++ b/net/ipv4/tcp.c
[...]
> @@ -1551,6 +1553,12 @@ int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
> struct sk_buff *skb;
> u32 urg_hole = 0;
>
> +#ifdef CONFIG_INET_LL_RX_POLL
> + if (sk_valid_ll(sk) && skb_queue_empty(&sk->sk_receive_queue)
> + && (sk->sk_state == TCP_ESTABLISHED))
> + sk_poll_ll(sk, nonblock);
> +#endif
[...]

I don't think the #ifdef is needed; this should compile down to nothing
if the config option is disabled.

Ben.

--
Ben Hutchings, Staff Engineer, Solarflare
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.