On Wed, 1 Nov 2017 13:47:17 +0000 Lawrence Brakmo <bra...@fb.com> wrote:
> Thank you for finding and fixing this. > > On 11/1/17, 6:32 AM, "Konstantin Khlebnikov" <khlebni...@yandex-team.ru> > wrote: > > Average RTT could become zero. This happened in real life at least twice. > This patch treats zero as 1us. > > Signed-off-by: Konstantin Khlebnikov khlebni...@yandex-team.ru > Acked-by: Lawrence Brakmo <bra...@fb.com> > --- > net/ipv4/tcp_nv.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/net/ipv4/tcp_nv.c b/net/ipv4/tcp_nv.c > index 1ff73982e28c..125fc1450b01 100644 > --- a/net/ipv4/tcp_nv.c > +++ b/net/ipv4/tcp_nv.c > @@ -252,7 +252,7 @@ static void tcpnv_acked(struct sock *sk, const struct > ack_sample *sample) > > /* rate in 100's bits per second */ > rate64 = ((u64)sample->in_flight) * 8000000; > - rate = (u32)div64_u64(rate64, (u64)(avg_rtt * 100)); > + rate = (u32)div64_u64(rate64, (u64)(avg_rtt ?: 1) * 100); Why is this code using expensive 64 bit by 64 bit divide when avg_rtt should never be bigger than 32 bits?
