Messages in this thread Patch in this message | | | From | Herton Ronaldo Krzesinski <> | Subject | [PATCH 68/81] tcp: fix for zero packets_in_flight was too broad | Date | Tue, 19 Feb 2013 15:49:31 -0300 |
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3.5.7.6 -stable review patch. If anyone has any objections, please let me know.
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From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= <ilpo.jarvinen@helsinki.fi>
commit 6731d2095bd4aef18027c72ef845ab1087c3ba63 upstream.
There are transients during normal FRTO procedure during which the packets_in_flight can go to zero between write_queue state updates and firing the resulting segments out. As FRTO processing occurs during that window the check must be more precise to not match "spuriously" :-). More specificly, e.g., when packets_in_flight is zero but FLAG_DATA_ACKED is true the problematic branch that set cwnd into zero would not be taken and new segments might be sent out later.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Tested-by: Eric Dumazet <edumazet@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> --- net/ipv4/tcp_input.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 6affa92..3b14d81 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -3695,8 +3695,7 @@ static bool tcp_process_frto(struct sock *sk, int flag) ((tp->frto_counter >= 2) && (flag & FLAG_RETRANS_DATA_ACKED))) tp->undo_marker = 0; - if (!before(tp->snd_una, tp->frto_highmark) || - !tcp_packets_in_flight(tp)) { + if (!before(tp->snd_una, tp->frto_highmark)) { tcp_enter_frto_loss(sk, (tp->frto_counter == 1 ? 2 : 3), flag); return true; } @@ -3716,6 +3715,11 @@ static bool tcp_process_frto(struct sock *sk, int flag) } } else { if (!(flag & FLAG_DATA_ACKED) && (tp->frto_counter == 1)) { + if (!tcp_packets_in_flight(tp)) { + tcp_enter_frto_loss(sk, 2, flag); + return true; + } + /* Prevent sending of new data. */ tp->snd_cwnd = min(tp->snd_cwnd, tcp_packets_in_flight(tp)); -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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