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| author | Doug Leith <doug.leith@nuim.ie> | 2008-11-12 01:41:09 -0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2008-11-12 01:41:09 -0800 |
| commit | 8f65b5354b1a34a536641bd915958662e8af5320 (patch) | |
| tree | 2870ccd815f0d8524487c1d33aa6349244e33b16 /net/ipv4/tcp_htcp.c | |
| parent | d809a1595610a7c0b0bd55f159e5dc37def0ac28 (diff) | |
| download | lwn-8f65b5354b1a34a536641bd915958662e8af5320.tar.gz lwn-8f65b5354b1a34a536641bd915958662e8af5320.zip | |
tcp_htcp: last_cong bug fix
This patch fixes a minor bug in tcp_htcp.c which has been
highlighted by Lachlan Andrew and Lawrence Stewart. Currently, the
time since the last congestion event, which is stored in variable
last_cong, is reset whenever there is a state change into
TCP_CA_Open. This includes transitions of the type
TCP_CA_Open->TCP_CA_Disorder->TCP_CA_Open which are not associated
with backoff of cwnd. The patch changes last_cong to be updated
only on transitions into TCP_CA_Open that occur after experiencing
the congestion-related states TCP_CA_Loss, TCP_CA_Recovery,
TCP_CA_CWR.
Signed-off-by: Doug Leith <doug.leith@nuim.ie>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_htcp.c')
| -rw-r--r-- | net/ipv4/tcp_htcp.c | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/net/ipv4/tcp_htcp.c b/net/ipv4/tcp_htcp.c index af99776146ff..937549b8a921 100644 --- a/net/ipv4/tcp_htcp.c +++ b/net/ipv4/tcp_htcp.c @@ -69,9 +69,12 @@ static u32 htcp_cwnd_undo(struct sock *sk) const struct tcp_sock *tp = tcp_sk(sk); struct htcp *ca = inet_csk_ca(sk); - ca->last_cong = ca->undo_last_cong; - ca->maxRTT = ca->undo_maxRTT; - ca->old_maxB = ca->undo_old_maxB; + if (ca->undo_last_cong) { + ca->last_cong = ca->undo_last_cong; + ca->maxRTT = ca->undo_maxRTT; + ca->old_maxB = ca->undo_old_maxB; + ca->undo_last_cong = 0; + } return max(tp->snd_cwnd, (tp->snd_ssthresh << 7) / ca->beta); } @@ -268,7 +271,10 @@ static void htcp_state(struct sock *sk, u8 new_state) case TCP_CA_Open: { struct htcp *ca = inet_csk_ca(sk); - ca->last_cong = jiffies; + if (ca->undo_last_cong) { + ca->last_cong = jiffies; + ca->undo_last_cong = 0; + } } break; case TCP_CA_CWR: |