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authorIlpo Järvinen <ilpo.jarvinen@helsinki.fi>2007-06-15 15:08:43 -0700
committerDavid S. Miller <davem@davemloft.net>2007-06-15 15:08:43 -0700
commitb9ce204f0a265f819d10c943a607746abb62f245 (patch)
tree45078d076bcd952d8820c590653939b312d06ac2 /net
parent22b1a9203ea634ac0ee5240e021613da3328275f (diff)
downloadlinux-b9ce204f0a265f819d10c943a607746abb62f245.tar.bz2
[TCP]: Congestion control API RTT sampling fix
Commit 164891aadf1721fca4dce473bb0e0998181537c6 broke RTT sampling of congestion control modules. Inaccurate timestamps could be fed to them without providing any way for them to identify such cases. Previously RTT sampler was called only if FLAG_RETRANS_DATA_ACKED was not set filtering inaccurate timestamps nicely. In addition, the new behavior could give an invalid timestamp (zero) to RTT sampler if only skbs with TCPCB_RETRANS were ACKed. This solves both problems. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/ipv4/tcp_illinois.c3
-rw-r--r--net/ipv4/tcp_input.c6
-rw-r--r--net/ipv4/tcp_lp.c3
-rw-r--r--net/ipv4/tcp_vegas.c3
-rw-r--r--net/ipv4/tcp_veno.c3
5 files changed, 16 insertions, 2 deletions
diff --git a/net/ipv4/tcp_illinois.c b/net/ipv4/tcp_illinois.c
index 4adc47c55351..b2b2256d3b84 100644
--- a/net/ipv4/tcp_illinois.c
+++ b/net/ipv4/tcp_illinois.c
@@ -90,6 +90,9 @@ static void tcp_illinois_acked(struct sock *sk, u32 pkts_acked, ktime_t last)
ca->acked = pkts_acked;
+ if (ktime_equal(last, net_invalid_timestamp()))
+ return;
+
rtt = ktime_to_us(net_timedelta(last));
/* ignore bogus values, this prevents wraparound in alpha math */
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index d6d0f9b6cdc6..aaf6f66677f9 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -2409,7 +2409,7 @@ static int tcp_clean_rtx_queue(struct sock *sk, __s32 *seq_rtt_p)
int acked = 0;
int prior_packets = tp->packets_out;
__s32 seq_rtt = -1;
- ktime_t last_ackt = ktime_set(0,0);
+ ktime_t last_ackt = net_invalid_timestamp();
while ((skb = tcp_write_queue_head(sk)) &&
skb != tcp_send_head(sk)) {
@@ -2487,6 +2487,10 @@ static int tcp_clean_rtx_queue(struct sock *sk, __s32 *seq_rtt_p)
tcp_ack_update_rtt(sk, acked, seq_rtt);
tcp_ack_packets_out(sk);
+ /* Is the ACK triggering packet unambiguous? */
+ if (acked & FLAG_RETRANS_DATA_ACKED)
+ last_ackt = net_invalid_timestamp();
+
if (ca_ops->pkts_acked)
ca_ops->pkts_acked(sk, pkts_acked, last_ackt);
}
diff --git a/net/ipv4/tcp_lp.c b/net/ipv4/tcp_lp.c
index 43294ad9f63e..e49836ce012e 100644
--- a/net/ipv4/tcp_lp.c
+++ b/net/ipv4/tcp_lp.c
@@ -266,7 +266,8 @@ static void tcp_lp_pkts_acked(struct sock *sk, u32 num_acked, ktime_t last)
struct tcp_sock *tp = tcp_sk(sk);
struct lp *lp = inet_csk_ca(sk);
- tcp_lp_rtt_sample(sk, ktime_to_us(net_timedelta(last)));
+ if (!ktime_equal(last, net_invalid_timestamp()))
+ tcp_lp_rtt_sample(sk, ktime_to_us(net_timedelta(last)));
/* calc inference */
if (tcp_time_stamp > tp->rx_opt.rcv_tsecr)
diff --git a/net/ipv4/tcp_vegas.c b/net/ipv4/tcp_vegas.c
index 73e19cf7df21..e218a51ceced 100644
--- a/net/ipv4/tcp_vegas.c
+++ b/net/ipv4/tcp_vegas.c
@@ -117,6 +117,9 @@ void tcp_vegas_pkts_acked(struct sock *sk, u32 cnt, ktime_t last)
struct vegas *vegas = inet_csk_ca(sk);
u32 vrtt;
+ if (ktime_equal(last, net_invalid_timestamp()))
+ return;
+
/* Never allow zero rtt or baseRTT */
vrtt = ktime_to_us(net_timedelta(last)) + 1;
diff --git a/net/ipv4/tcp_veno.c b/net/ipv4/tcp_veno.c
index 9edb340f2f95..ec854cc5fad5 100644
--- a/net/ipv4/tcp_veno.c
+++ b/net/ipv4/tcp_veno.c
@@ -74,6 +74,9 @@ static void tcp_veno_pkts_acked(struct sock *sk, u32 cnt, ktime_t last)
struct veno *veno = inet_csk_ca(sk);
u32 vrtt;
+ if (ktime_equal(last, net_invalid_timestamp()))
+ return;
+
/* Never allow zero rtt or baseRTT */
vrtt = ktime_to_us(net_timedelta(last)) + 1;