From 2594a2a928a010bf27e6545f90bc2de7ed5ed075 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 9 Sep 2016 14:22:45 -0700 Subject: [PATCH] tcp: better use ooo_last_skb in tcp_data_queue_ofo() MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Willem noticed that we could avoid an rbtree lookup if the the attempt to coalesce incoming skb to the last skb failed for some reason. Since most ooo additions are at the tail, this is definitely worth adding a test and fast path. Suggested-by: Willem de Bruijn Signed-off-by: Eric Dumazet Cc: Yaogong Wang Cc: Yuchung Cheng Cc: Neal Cardwell Cc: Ilpo Järvinen Signed-off-by: David S. Miller --- net/ipv4/tcp_input.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index a5934c4c8cd4..70b892db9901 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -4461,6 +4461,12 @@ coalesce_done: skb = NULL; goto add_sack; } + /* Can avoid an rbtree lookup if we are adding skb after ooo_last_skb */ + if (!before(seq, TCP_SKB_CB(tp->ooo_last_skb)->end_seq)) { + parent = &tp->ooo_last_skb->rbnode; + p = &parent->rb_right; + goto insert; + } /* Find place to insert this segment. Handle overlaps on the way. */ parent = NULL; @@ -4503,7 +4509,7 @@ coalesce_done: } p = &parent->rb_right; } - +insert: /* Insert segment into RB tree. */ rb_link_node(&skb->rbnode, parent, p); rb_insert_color(&skb->rbnode, &tp->out_of_order_queue); -- 2.39.2