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From:   Yafang Shao <laoar.shao@gmail.com>
Date:   Wed, 25 Jul 2018 21:59:57 +0800
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Subject: Re: [PATCH net-next] tcp: add SNMP counter for the number of packets
 pruned from ofo queue
To:     Eric Dumazet <eric.dumazet@gmail.com>
Cc:     David Miller <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        netdev <netdev@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>
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On Wed, Jul 25, 2018 at 9:55 PM, Eric Dumazet <eric.dumazet@gmail.com> wrote:
>
>
> On 07/25/2018 06:40 AM, Yafang Shao wrote:
>
>>
>> Because we want to know why packets were dropped.
>> If that could be show in netstat, we could easily find that it is
>> dropped due to ofo prune.
>
>
> We have a counter already for these events : LINUX_MIB_OFOPRUNED
>
> You want to add another counter tracking number of _skbs_,
> which has no precise value for user,
> given each skb can contain a variable number of _packets_.
>

Got it.

But with LINUX_MIB_OFOPRUNED, we only know  tcp_prune_ofo_queue is
called, but have no idea how many skbs are dropped.

Thanks
Yafang