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From:   Eric Dumazet <edumazet@google.com>
Date:   Sun, 9 Sep 2018 11:27:22 -0700
Message-ID: <CANn89i+yXq2LgCn=oSoQJhx9dFSf570wjbV5Rzb+VrxfVZA1dQ@mail.gmail.com>
Subject: Re: [PATCH v2 net-next 1/2] tcp: show number of network segments in
 some SNMP counters
To:     Yafang Shao <laoar.shao@gmail.com>
Cc:     David Miller <davem@davemloft.net>,
        netdev <netdev@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>
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On Sat, Sep 8, 2018 at 8:14 PM Yafang Shao <laoar.shao@gmail.com> wrote:
>
> It is better to show the number of network segments in bellow SNMP
> counters, because that could be more useful for the user.
> For example, the user could easily figure out how mant packets are
> dropped and how many packets are queued in the out-of-oder queue.
>
> - LINUX_MIB_TCPRCVQDROP
> - LINUX_MIB_TCPZEROWINDOWDROP
> - LINUX_MIB_TCPBACKLOGDROP
> - LINUX_MIB_TCPMINTTLDROP
> - LINUX_MIB_TCPOFODROP
> - LINUX_MIB_TCPOFOQUEUE
>
> Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
> ---
>  net/ipv4/tcp_input.c | 18 ++++++++++++------
>  net/ipv4/tcp_ipv4.c  |  9 ++++++---
>  net/ipv6/tcp_ipv6.c  |  6 ++++--
>  3 files changed, 22 insertions(+), 11 deletions(-)
>
> diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
> index 62508a2..c2ce334 100644
> --- a/net/ipv4/tcp_input.c
> +++ b/net/ipv4/tcp_input.c
> @@ -4496,7 +4496,8 @@ static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb)
>         tcp_ecn_check_ce(sk, skb);
>
>         if (unlikely(tcp_try_rmem_schedule(sk, skb, skb->truesize))) {
> -               NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPOFODROP);
> +               NET_ADD_STATS(sock_net(sk), LINUX_MIB_TCPOFODROP,
> +                             max_t(u16, 1, skb_shinfo(skb)->gso_segs));
>

I am nacking this patch. These counters are counting events really.