From: Eric Dumazet <[email protected]> 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 <[email protected]> Signed-off-by: Eric Dumazet <[email protected]> Cc: Yaogong Wang <[email protected]> Cc: Yuchung Cheng <[email protected]> Cc: Neal Cardwell <[email protected]> Cc: Ilpo Järvinen <[email protected]> --- 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..2e26f3eb0293 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);
