From ea4ca586b16ff2eb6157fe13969eb72d2403a3a1 Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Thu, 19 Nov 2020 11:46:03 -0800 Subject: mptcp: refine MPTCP-level ack scheduling Send timely MPTCP-level ack is somewhat difficult when the insertion into the msk receive level is performed by the worker. It needs TCP-level dup-ack to notify the MPTCP-level ack_seq increase, as both the TCP-level ack seq and the rcv window are unchanged. We can actually avoid processing incoming data with the worker, and let the subflow or recevmsg() send ack as needed. When recvmsg() moves the skbs inside the msk receive queue, the msk space is still unchanged, so tcp_cleanup_rbuf() could end-up skipping TCP-level ack generation. Anyway, when __mptcp_move_skbs() is invoked, a known amount of bytes is going to be consumed soon: we update rcv wnd computation taking them in account. Additionally we need to explicitly trigger tcp_cleanup_rbuf() when recvmsg() consumes a significant amount of the receive buffer. Signed-off-by: Paolo Abeni Signed-off-by: Mat Martineau Signed-off-by: Jakub Kicinski --- net/mptcp/protocol.h | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'net/mptcp/protocol.h') diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h index 67f86818203f..82d5626323b1 100644 --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -220,10 +220,12 @@ struct mptcp_sock { u64 rcv_data_fin_seq; struct sock *last_snd; int snd_burst; + int old_wspace; atomic64_t snd_una; atomic64_t wnd_end; unsigned long timer_ival; u32 token; + int rmem_pending; unsigned long flags; bool can_ack; bool fully_established; @@ -231,6 +233,7 @@ struct mptcp_sock { bool snd_data_fin_enable; bool use_64bit_ack; /* Set when we received a 64-bit DSN */ spinlock_t join_list_lock; + struct sock *ack_hint; struct work_struct work; struct sk_buff *ooo_last_skb; struct rb_root out_of_order_queue; @@ -258,6 +261,11 @@ static inline struct mptcp_sock *mptcp_sk(const struct sock *sk) return (struct mptcp_sock *)sk; } +static inline int __mptcp_space(const struct sock *sk) +{ + return tcp_space(sk) + READ_ONCE(mptcp_sk(sk)->rmem_pending); +} + static inline struct mptcp_data_frag *mptcp_send_head(const struct sock *sk) { const struct mptcp_sock *msk = mptcp_sk(sk); -- cgit