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| author | Eric Dumazet <edumazet@google.com> | 2016-02-11 08:58:18 -0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2016-02-16 16:07:13 -0500 |
| commit | 372022830b06d9980c7e8b41fa0a4081cff883b0 (patch) | |
| tree | f3b5d5280ef7720ab66f8d9b015cf8fe7e0ef8a8 /net | |
| parent | 6c5d89a34a486ad782dfb5b6b3b8fb4976ae7619 (diff) | |
| download | lwn-372022830b06d9980c7e8b41fa0a4081cff883b0.tar.gz lwn-372022830b06d9980c7e8b41fa0a4081cff883b0.zip | |
tcp: do not set rtt_min to 1
There are some cases where rtt_us derives from deltas of jiffies,
instead of using usec timestamps.
Since we want to track minimal rtt, better to assume a delta of 0 jiffie
might be in fact be very close to 1 jiffie.
It is kind of sad jiffies_to_usecs(1) calls a function instead of simply
using a constant.
Fixes: f672258391b42 ("tcp: track min RTT using windowed min-filter")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv4/tcp_input.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 1c2a73406261..3b2c8e90a475 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -2896,7 +2896,10 @@ static void tcp_update_rtt_min(struct sock *sk, u32 rtt_us) { const u32 now = tcp_time_stamp, wlen = sysctl_tcp_min_rtt_wlen * HZ; struct rtt_meas *m = tcp_sk(sk)->rtt_min; - struct rtt_meas rttm = { .rtt = (rtt_us ? : 1), .ts = now }; + struct rtt_meas rttm = { + .rtt = likely(rtt_us) ? rtt_us : jiffies_to_usecs(1), + .ts = now, + }; u32 elapsed; /* Check if the new measurement updates the 1st, 2nd, or 3rd choices */ |