From mboxrd@z Thu Jan 1 00:00:00 1970 From: Koichiro Den Subject: [net-next 1/3] tcp: avoid useless copying and collapsing of just one skb Date: Sat, 14 Oct 2017 16:27:43 +0900 Message-ID: <20171014072745.23462-2-den@klaipeden.com> References: <20171014072745.23462-1-den@klaipeden.com> Cc: davem@davemloft.net, kuznet@ms2.inr.ac.ru, yoshfuji@linux-ipv6.org To: netdev@vger.kernel.org Return-path: Received: from sender-of-o52.zoho.com ([135.84.80.217]:21412 "EHLO sender-of-o52.zoho.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751737AbdJNH2C (ORCPT ); Sat, 14 Oct 2017 03:28:02 -0400 In-Reply-To: <20171014072745.23462-1-den@klaipeden.com> Sender: netdev-owner@vger.kernel.org List-ID: On the starting point chosen, it could be possible that just one skb remains in between the range provided, leading to copying and re-insertion of rb node, which is useless with respect to the rcv buf measurement. This is rather probable in ooo queue case, in which non-contiguous bloated packets have been queued up. Signed-off-by: Koichiro Den --- net/ipv4/tcp_input.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index d0682ce2a5d6..1d785b5bf62d 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -4807,7 +4807,8 @@ tcp_collapse(struct sock *sk, struct sk_buff_head *list, struct rb_root *root, start = TCP_SKB_CB(skb)->end_seq; } if (end_of_skbs || - (TCP_SKB_CB(skb)->tcp_flags & (TCPHDR_SYN | TCPHDR_FIN))) + (TCP_SKB_CB(skb)->tcp_flags & (TCPHDR_SYN | TCPHDR_FIN)) || + (TCP_SKB_CB(skb)->seq == start && TCP_SKB_CB(skb)->end_seq == end)) return; __skb_queue_head_init(&tmp); -- 2.9.4