Re: [net-next, 3/3] tcp: convert icsk_user_timeout from jiffies to msecs

From: Jonathan Maxwell
Date: Mon Jul 16 2018 - 19:18:20 EST


Sorry Eric, my bad. I'll do another version with the indentation fixed and
reformatting of min_t() and resubmit.

On Tue, Jul 17, 2018 at 2:00 AM, Eric Dumazet <eric.dumazet@xxxxxxxxx> wrote:
>
>
> On 07/12/2018 05:49 PM, Jon Maxwell wrote:
>> The final patch in this series. Create the tcp_clamp_rto_to_user_timeout()
>> helper routine. To calculate the correct rto, so that the TCP_USER_TIMEOUT
>> socket option is more accurate. Taking suggestions and feedback into account
>> from Eric Dumazet, Neal Cardwell and David Laight. Due to the 1st commit we
>> can avoid the msecs_to_jiffies() and jiffies_to_msecs() dance.
>>
>> Signed-off-by: Jon Maxwell <jmaxwell37@xxxxxxxxx>
>> ---
>> net/ipv4/tcp_timer.c | 19 ++++++++++++++++++-
>> 1 file changed, 18 insertions(+), 1 deletion(-)
>>
>> diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c
>> index 8ab8c9645294..d4d4b30a6bec 100644
>> --- a/net/ipv4/tcp_timer.c
>> +++ b/net/ipv4/tcp_timer.c
>> @@ -36,6 +36,22 @@ u32 tcp_retransmit_stamp(const struct sock *sk)
>> return start_ts;
>> }
>>
>> +static u32 tcp_clamp_rto_to_user_timeout(const struct sock *sk)
>> +{
>> + struct inet_connection_sock *icsk = inet_csk(sk);
>> + u32 elapsed, start_ts;
>> +
>> + start_ts = tcp_retransmit_stamp(sk);
>> + if (!icsk->icsk_user_timeout || !start_ts)
>> + return icsk->icsk_rto;
>> + elapsed = tcp_time_stamp(tcp_sk(sk)) - start_ts;
>> + if (elapsed >= icsk->icsk_user_timeout)
>> + return 1; /* user timeout has passed; fire ASAP */
>> + else
>> + return min_t(u32, icsk->icsk_rto, msecs_to_jiffies(icsk->icsk_user_timeout -
>> + elapsed));
>
> if (elapsed >= icsk->icsk_user_timeout)
> return 1; /* user timeout has passed; fire ASAP */
>
> return min_t(u32, icsk->icsk_rto, msecs_to_jiffies(icsk->icsk_user_timeout - elapsed));
>
> Thanks !