From b76892051cf1c04d95872838e70146f65e3b9d75 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Ilpo=20J=C3=A4rvinen?= Date: Thu, 20 Sep 2007 11:37:19 -0700 Subject: [PATCH] [TCP]: Avoid clearing sacktag hint in trivial situations MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 Signed-off-by: David S. Miller --- include/net/tcp.h | 6 +++++- net/ipv4/tcp_input.c | 14 ++++++++------ net/ipv4/tcp_output.c | 12 ++++++++---- 3 files changed, 21 insertions(+), 11 deletions(-) diff --git a/include/net/tcp.h b/include/net/tcp.h index d78ad9bfcf..456983d1fc 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -1067,11 +1067,15 @@ static inline void tcp_mib_init(void) } /* from STCP */ -static inline void tcp_clear_all_retrans_hints(struct tcp_sock *tp) { +static inline void tcp_clear_retrans_hints_partial(struct tcp_sock *tp) { tp->lost_skb_hint = NULL; tp->scoreboard_skb_hint = NULL; tp->retransmit_skb_hint = NULL; tp->forward_skb_hint = NULL; +} + +static inline void tcp_clear_all_retrans_hints(struct tcp_sock *tp) { + tcp_clear_retrans_hints_partial(tp); tp->fastpath_skb_hint = NULL; } diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 65b9f274a7..4c10d9cad2 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -1671,7 +1671,7 @@ static void tcp_enter_frto_loss(struct sock *sk, int allowed_segments, int flag) tp->high_seq = tp->frto_highmark; TCP_ECN_queue_cwr(tp); - tcp_clear_all_retrans_hints(tp); + tcp_clear_retrans_hints_partial(tp); } void tcp_clear_retrans(struct tcp_sock *tp) @@ -1711,10 +1711,14 @@ void tcp_enter_loss(struct sock *sk, int how) tp->bytes_acked = 0; tcp_clear_retrans(tp); - /* Push undo marker, if it was plain RTO and nothing - * was retransmitted. */ - if (!how) + if (!how) { + /* Push undo marker, if it was plain RTO and nothing + * was retransmitted. */ tp->undo_marker = tp->snd_una; + tcp_clear_retrans_hints_partial(tp); + } else { + tcp_clear_all_retrans_hints(tp); + } tcp_for_write_queue(skb, sk) { if (skb == tcp_send_head(sk)) @@ -1741,8 +1745,6 @@ void tcp_enter_loss(struct sock *sk, int how) TCP_ECN_queue_cwr(tp); /* Abort FRTO algorithm if one is in progress */ tp->frto_counter = 0; - - tcp_clear_all_retrans_hints(tp); } static int tcp_check_sack_reneging(struct sock *sk) diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index f46d24b841..cbb83acd83 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -687,7 +687,7 @@ int tcp_fragment(struct sock *sk, struct sk_buff *skb, u32 len, unsigned int mss 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 @@ static void tcp_retrans_try_collapse(struct sock *sk, struct sk_buff *skb, int m 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 @@ static void tcp_retrans_try_collapse(struct sock *sk, struct sk_buff *skb, int m 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); } } -- 2.39.5