[TCP]: Avoid clearing sacktag hint in trivial situations
There's no reason to clear the sacktag skb hint when small part
of the rexmit queue changes. Account changes (if any) instead when
fragmenting/collapsing. RTO/FRTO do not touch SACKED_ACKED bits so
no need to discard SACK tag hint at all.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index f46d24b..cbb83ac 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -687,7 +687,7 @@
BUG_ON(len > skb->len);
- tcp_clear_all_retrans_hints(tp);
+ tcp_clear_retrans_hints_partial(tp);
nsize = skb_headlen(skb) - len;
if (nsize < 0)
nsize = 0;
@@ -1718,9 +1718,6 @@
BUG_ON(tcp_skb_pcount(skb) != 1 ||
tcp_skb_pcount(next_skb) != 1);
- /* changing transmit queue under us so clear hints */
- tcp_clear_all_retrans_hints(tp);
-
/* Ok. We will be able to collapse the packet. */
tcp_unlink_write_queue(next_skb, sk);
@@ -1759,6 +1756,13 @@
tcp_adjust_fackets_out(tp, skb, tcp_skb_pcount(next_skb));
tp->packets_out -= tcp_skb_pcount(next_skb);
+
+ /* changed transmit queue under us so clear hints */
+ tcp_clear_retrans_hints_partial(tp);
+ /* manually tune sacktag skb hint */
+ if (tp->fastpath_skb_hint == next_skb)
+ tp->fastpath_skb_hint = skb;
+
sk_stream_free_skb(sk, next_skb);
}
}