diff options
| author | Eric Dumazet <edumazet@google.com> | 2019-04-16 10:55:20 -0700 |
|---|---|---|
| committer | Jason Liu <jason.hui.liu@nxp.com> | 2019-09-06 15:49:42 +0800 |
| commit | dd6576501654cace0cc88de0af81e42ce7ffc203 (patch) | |
| tree | a016f7d1c64b1aa30bf6bb475fd67800b741a77d /net | |
| parent | 9dbc3fe1488d1af40f677b4962d53b6e74e053f5 (diff) | |
tcp: tcp_grow_window() needs to respect tcp_space()
[ Upstream commit 50ce163a72d817a99e8974222dcf2886d5deb1ae ]
For some reason, tcp_grow_window() correctly tests if enough room
is present before attempting to increase tp->rcv_ssthresh,
but does not prevent it to grow past tcp_space()
This is causing hard to debug issues, like failing
the (__tcp_select_window(sk) >= tp->rcv_wnd) test
in __tcp_ack_snd_check(), causing ACK delays and possibly
slow flows.
Depending on tcp_rmem[2], MTU, skb->len/skb->truesize ratio,
we can see the problem happening on "netperf -t TCP_RR -- -r 2000,2000"
after about 60 round trips, when the active side no longer sends
immediate acks.
This bug predates git history.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Wei Wang <weiwan@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit 07b1747f11af7cb3ed0903cd8bf3b5a382452ec4)
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv4/tcp_input.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index c8227e07d574..657d33e2ff6a 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -389,11 +389,12 @@ static int __tcp_grow_window(const struct sock *sk, const struct sk_buff *skb) static void tcp_grow_window(struct sock *sk, const struct sk_buff *skb) { struct tcp_sock *tp = tcp_sk(sk); + int room; + + room = min_t(int, tp->window_clamp, tcp_space(sk)) - tp->rcv_ssthresh; /* Check #1 */ - if (tp->rcv_ssthresh < tp->window_clamp && - (int)tp->rcv_ssthresh < tcp_space(sk) && - !tcp_under_memory_pressure(sk)) { + if (room > 0 && !tcp_under_memory_pressure(sk)) { int incr; /* Check #2. Increase window, if skb with such overhead @@ -406,8 +407,7 @@ static void tcp_grow_window(struct sock *sk, const struct sk_buff *skb) if (incr) { incr = max_t(int, incr, 2 * skb->len); - tp->rcv_ssthresh = min(tp->rcv_ssthresh + incr, - tp->window_clamp); + tp->rcv_ssthresh += min(room, incr); inet_csk(sk)->icsk_ack.quick |= 1; } } |