Commit 37202283 authored Feb 11, 2016 by Eric Dumazet Committed by David S. Miller Feb 16, 2016

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: f6722583 ("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>

parent 6c5d89a3

net/ipv4/tcp_input.c

+4 −1

Original line number	Diff line number	Diff line
		@@ -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 */

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