Commit da51aef5 authored by Paolo Abeni's avatar Paolo Abeni Committed by David S. Miller
Browse files

mptcp: basic sndbuf autotuning 



Let the msk sendbuf track the size of the larger subflow's
send window, so that we ensure mptcp_sendmsg() does not
exceed MPTCP-level send window.

The update is performed just before try to send any data.

Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
Reviewed-by: default avatarMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 6719331c

net/mptcp/protocol.c

+13 −4
Original line number Diff line number Diff line
@@ -856,7 +856,8 @@ static void mptcp_nospace(struct mptcp_sock *msk) 
	}

}



static struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk)

static struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk,

					   u32 *sndbuf)

{

	struct mptcp_subflow_context *subflow;

	struct sock *sk = (struct sock *)msk;
@@ -865,6 +866,7 @@ static struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk) 


	sock_owned_by_me(sk);



	*sndbuf = 0;

	if (!mptcp_ext_cache_refill(msk))

		return NULL;
@@ -877,6 +879,7 @@ static struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk) 
			return NULL;

		}



		*sndbuf = max(tcp_sk(ssk)->snd_wnd, *sndbuf);

		if (subflow->backup) {

			if (!backup)

				backup = ssk;
@@ -903,6 +906,7 @@ static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) 
	struct page_frag *pfrag;

	size_t copied = 0;

	struct sock *ssk;

	u32 sndbuf;

	bool tx_ok;

	long timeo;
@@ -929,7 +933,7 @@ restart: 
	}



	__mptcp_flush_join_list(msk);

	ssk = mptcp_subflow_get_send(msk);

	ssk = mptcp_subflow_get_send(msk, &sndbuf);

	while (!sk_stream_memory_free(sk) ||

	       !ssk ||

	       !mptcp_page_frag_refill(ssk, pfrag)) {
@@ -953,13 +957,18 @@ restart: 


		mptcp_clean_una(sk);



		ssk = mptcp_subflow_get_send(msk);

		ssk = mptcp_subflow_get_send(msk, &sndbuf);

		if (list_empty(&msk->conn_list)) {

			ret = -ENOTCONN;

			goto out;

		}

	}



	/* do auto tuning */

	if (!(sk->sk_userlocks & SOCK_SNDBUF_LOCK) &&

	    sndbuf > READ_ONCE(sk->sk_sndbuf))

		WRITE_ONCE(sk->sk_sndbuf, sndbuf);



	pr_debug("conn_list->subflow=%p", ssk);



	lock_sock(ssk);
@@ -1547,7 +1556,7 @@ static int mptcp_init_sock(struct sock *sk) 


	sk_sockets_allocated_inc(sk);

	sk->sk_rcvbuf = sock_net(sk)->ipv4.sysctl_tcp_rmem[1];

	sk->sk_sndbuf = sock_net(sk)->ipv4.sysctl_tcp_wmem[2];

	sk->sk_sndbuf = sock_net(sk)->ipv4.sysctl_tcp_wmem[1];



	return 0;

}

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