diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 0ca87547becbe939c19e93c6f68983c40087da86..d099f9a055c6d30570deb7deceea3a21c4379a3e 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -622,19 +622,21 @@ static inline void tcp_mark_urg(struct tcp_sock *tp, int flags) } /* If a not yet filled skb is pushed, do not send it if - * we have packets in Qdisc or NIC queues : + * we have data packets in Qdisc or NIC queues : * Because TX completion will happen shortly, it gives a chance * to coalesce future sendmsg() payload into this skb, without * need for a timer, and with no latency trade off. * As packets containing data payload have a bigger truesize - * than pure acks (dataless) packets, the last check prevents - * autocorking if we only have an ACK in Qdisc/NIC queues. + * than pure acks (dataless) packets, the last checks prevent + * autocorking if we only have an ACK in Qdisc/NIC queues, + * or if TX completion was delayed after we processed ACK packet. */ static bool tcp_should_autocork(struct sock *sk, struct sk_buff *skb, int size_goal) { return skb->len < size_goal && sysctl_tcp_autocorking && + skb != tcp_write_queue_head(sk) && atomic_read(&sk->sk_wmem_alloc) > skb->truesize; } @@ -660,7 +662,11 @@ static void tcp_push(struct sock *sk, int flags, int mss_now, NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAUTOCORKING); set_bit(TSQ_THROTTLED, &tp->tsq_flags); } - return; + /* It is possible TX completion already happened + * before we set TSQ_THROTTLED. + */ + if (atomic_read(&sk->sk_wmem_alloc) > skb->truesize) + return; } if (flags & MSG_MORE)