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[mptcp-next,1/7] mptcp: push ad DSS boundaries

Message ID 59d94e4297902d25829276df006615bbdd5f717f.1705836321.git.pabeni@redhat.com (mailing list archive)
State Superseded, archived
Delegated to: Mat Martineau
Headers show
Series mptcp: implement TCP_NOTSENT_LOWAT support | expand

Commit Message

Paolo Abeni Jan. 22, 2024, 3:08 p.m. UTC
when inserting/creating skbs on the subflow write queue, if
the to-be-appended data don't is not contiguous to the tail data,
the protocol creates a new skb and prevent the TCP stack from
merging it later by setting the EOR marker.

Still no push flag is explicitly set at the end of previous GSO
packet, making the aggregation on the receiver side sub-optimal -
and packetdrill self-tests less predictable.

Explicitly mark the end of not contiguous DSS with the push flag.

Fixes: 6d0060f600ad ("mptcp: Write MPTCP DSS headers to outgoing data packets")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
This could also land on next, as needed, dropping the fixes tag
---
 net/mptcp/protocol.c | 1 +
 1 file changed, 1 insertion(+)

Comments

Mat Martineau Feb. 8, 2024, 1:55 a.m. UTC | #1
On Mon, 22 Jan 2024, Paolo Abeni wrote:

> when inserting/creating skbs on the subflow write queue, if
> the to-be-appended data don't is not contiguous to the tail data,

Hi Paolo -

Looks like the "don't" here is extra, can you clarify this sentence?

> the protocol creates a new skb and prevent the TCP stack from
> merging it later by setting the EOR marker.
>
> Still no push flag is explicitly set at the end of previous GSO
> packet, making the aggregation on the receiver side sub-optimal -
> and packetdrill self-tests less predictable.
>
> Explicitly mark the end of not contiguous DSS with the push flag.
>

I agree with the approach, gro will never benefit from waiting around for 
the next packet as it will have a new DSS header and can never be 
combined.

- Mat

> Fixes: 6d0060f600ad ("mptcp: Write MPTCP DSS headers to outgoing data packets")
> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
> ---
> This could also land on next, as needed, dropping the fixes tag
> ---
> net/mptcp/protocol.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
> index 744b4d6f15f4..4d7131f96ebf 100644
> --- a/net/mptcp/protocol.c
> +++ b/net/mptcp/protocol.c
> @@ -1264,6 +1264,7 @@ static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk,
> 		mpext = mptcp_get_ext(skb);
> 		if (!mptcp_skb_can_collapse_to(data_seq, skb, mpext)) {
> 			TCP_SKB_CB(skb)->eor = 1;
> +			tcp_mark_push(tcp_sk(ssk), skb);
> 			goto alloc_skb;
> 		}
>
> -- 
> 2.43.0
>
>
>
diff mbox series

Patch

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 744b4d6f15f4..4d7131f96ebf 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -1264,6 +1264,7 @@  static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk,
 		mpext = mptcp_get_ext(skb);
 		if (!mptcp_skb_can_collapse_to(data_seq, skb, mpext)) {
 			TCP_SKB_CB(skb)->eor = 1;
+			tcp_mark_push(tcp_sk(ssk), skb);
 			goto alloc_skb;
 		}