netdev - Re: [PATCH v3 net-next] tcp: Change txhash on every SYN and RTO retransmit

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Date:   Tue, 27 Sep 2016 21:28:11 -0400
From:   Neal Cardwell <ncardwell@...gle.com>
To:     Yuchung Cheng <ycheng@...gle.com>
Cc:     Lawrence Brakmo <brakmo@...com>, netdev <netdev@...r.kernel.org>,
        Kernel Team <kernel-team@...com>,
        Eric Dumazet <eric.dumazet@...il.com>
Subject: Re: [PATCH v3 net-next] tcp: Change txhash on every SYN and RTO retransmit

On Tue, Sep 27, 2016 at 8:18 PM, Yuchung Cheng <ycheng@...gle.com> wrote:
> On Tue, Sep 27, 2016 at 4:31 PM, Lawrence Brakmo <brakmo@...com> wrote:
>> @@ -213,6 +215,8 @@ static int tcp_write_timeout(struct sock *sk)
>>                         tcp_mtu_probing(icsk, sk);
>>
>>                         dst_negative_advice(sk);
>> +               } else if (prandom_u32_max(100) < sysctl_tcp_rto_txhash_prob) {
> The sysctl is not really needed but that's just my opinion.

I agree that it sounds nice to simplify by not having a sysctl for
this and always calling sk_rethink_txhash() here.

neal