diff options
| author | Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> | 2006-09-19 12:52:50 -0700 |
|---|---|---|
| committer | David S. Miller <davem@sunset.davemloft.net> | 2006-09-22 15:19:05 -0700 |
| commit | 1ef9696c909060ccdae3ade245ca88692b49285b (patch) | |
| tree | 3a2df5bbd6b448a4f873125ab5dd7c7a0cc7ae05 | |
| parent | 4eb327b517cf85f6cb7dcd5691e7b748cbe8c343 (diff) | |
[TCP]: Send ACKs each 2nd received segment.
It does not affect either mss-sized connections (obviously) or
connections controlled by Nagle (because there is only one small
segment in flight).
The idea is to record the fact that a small segment arrives on a
connection, where one small segment has already been received and
still not-ACKed. In this case ACK is forced after tcp_recvmsg() drains
receive buffer.
In other words, it is a "soft" each-2nd-segment ACK, which is enough
to preserve ACK clock even when ABC is enabled.
Signed-off-by: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | include/net/inet_connection_sock.h | 3 | ||||
| -rw-r--r-- | net/ipv4/tcp.c | 7 | ||||
| -rw-r--r-- | net/ipv4/tcp_input.c | 2 |
3 files changed, 9 insertions, 3 deletions
diff --git a/include/net/inet_connection_sock.h b/include/net/inet_connection_sock.h index 9bf73fe5094..de4e83b6da4 100644 --- a/include/net/inet_connection_sock.h +++ b/include/net/inet_connection_sock.h @@ -147,7 +147,8 @@ extern struct sock *inet_csk_clone(struct sock *sk, enum inet_csk_ack_state_t { ICSK_ACK_SCHED = 1, ICSK_ACK_TIMER = 2, - ICSK_ACK_PUSHED = 4 + ICSK_ACK_PUSHED = 4, + ICSK_ACK_PUSHED2 = 8 }; extern void inet_csk_init_xmit_timers(struct sock *sk, diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 29e3d606db7..66e9a729f6d 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -955,8 +955,11 @@ void tcp_cleanup_rbuf(struct sock *sk, int copied) * receive buffer and there was a small segment * in queue. */ - (copied > 0 && (icsk->icsk_ack.pending & ICSK_ACK_PUSHED) && - !icsk->icsk_ack.pingpong && !atomic_read(&sk->sk_rmem_alloc))) + (copied > 0 && + ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) || + ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) && + !icsk->icsk_ack.pingpong)) && + !atomic_read(&sk->sk_rmem_alloc))) time_to_ack = 1; } diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 511b738f118..b3def0df14f 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -156,6 +156,8 @@ static void tcp_measure_rcv_mss(struct sock *sk, return; } } + if (icsk->icsk_ack.pending & ICSK_ACK_PUSHED) + icsk->icsk_ack.pending |= ICSK_ACK_PUSHED2; icsk->icsk_ack.pending |= ICSK_ACK_PUSHED; } } |