diff --git a/include/linux/snmp.h b/include/linux/snmp.h index 8ee8af4e6da9..2e68f5ba0389 100644 --- a/include/linux/snmp.h +++ b/include/linux/snmp.h @@ -233,6 +233,7 @@ enum LINUX_MIB_TCPREQQFULLDOCOOKIES, /* TCPReqQFullDoCookies */ LINUX_MIB_TCPREQQFULLDROP, /* TCPReqQFullDrop */ LINUX_MIB_TCPRETRANSFAIL, /* TCPRetransFail */ + LINUX_MIB_TCPRCVCOALESCE, /* TCPRcvCoalesce */ __LINUX_MIB_MAX }; diff --git a/net/ipv4/proc.c b/net/ipv4/proc.c index 02d61079f08b..8af0d44e4e22 100644 --- a/net/ipv4/proc.c +++ b/net/ipv4/proc.c @@ -257,6 +257,7 @@ static const struct snmp_mib snmp4_net_list[] = { SNMP_MIB_ITEM("TCPReqQFullDoCookies", LINUX_MIB_TCPREQQFULLDOCOOKIES), SNMP_MIB_ITEM("TCPReqQFullDrop", LINUX_MIB_TCPREQQFULLDROP), SNMP_MIB_ITEM("TCPRetransFail", LINUX_MIB_TCPRETRANSFAIL), + SNMP_MIB_ITEM("TCPRcvCoalesce", LINUX_MIB_TCPRCVCOALESCE), SNMP_MIB_SENTINEL }; diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index fa7de12c4a52..e886e2f7fa8d 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -4484,7 +4484,24 @@ static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb) end_seq = TCP_SKB_CB(skb)->end_seq; if (seq == TCP_SKB_CB(skb1)->end_seq) { - __skb_queue_after(&tp->out_of_order_queue, skb1, skb); + /* Packets in ofo can stay in queue a long time. + * Better try to coalesce them right now + * to avoid future tcp_collapse_ofo_queue(), + * probably the most expensive function in tcp stack. + */ + if (skb->len <= skb_tailroom(skb1) && !tcp_hdr(skb)->fin) { + NET_INC_STATS_BH(sock_net(sk), + LINUX_MIB_TCPRCVCOALESCE); + BUG_ON(skb_copy_bits(skb, 0, + skb_put(skb1, skb->len), + skb->len)); + TCP_SKB_CB(skb1)->end_seq = end_seq; + TCP_SKB_CB(skb1)->ack_seq = TCP_SKB_CB(skb)->ack_seq; + __kfree_skb(skb); + skb = NULL; + } else { + __skb_queue_after(&tp->out_of_order_queue, skb1, skb); + } if (!tp->rx_opt.num_sacks || tp->selective_acks[0].end_seq != seq)