Re: [PATCH net-next 1/2] tcp: call tcp_drop() in tcp collapse

From: Yafang Shao <laoar.shao@gmail.com>
To: Eric Dumazet <edumazet@google.com>
Cc: Brendan Gregg <bgregg@netflix.com>,
	David Miller <davem@davemloft.net>,
	netdev <netdev@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH net-next 1/2] tcp: call tcp_drop() in tcp collapse
Date: Tue, 31 Jul 2018 08:48:49 +0800	[thread overview]
Message-ID: <CALOAHbCcK5OoGn1Zc_CDYwM9FXKgi0wk8zq8xB1wHyH4iZTxZA@mail.gmail.com> (raw)
In-Reply-To: <CANn89iK4KLHww-R2JmNr-tYVcUWevq6ceFQW0qE2mJCsq6eL-g@mail.gmail.com>

On Mon, Jul 30, 2018 at 11:56 PM, Eric Dumazet <edumazet@google.com> wrote:
> On Sun, Jul 29, 2018 at 10:40 PM Yafang Shao <laoar.shao@gmail.com> wrote:
>
>> Should we put NET_INC_STATS(sock_net(sk),  mib_idx) into the funtion
>> tcp_drop() ?
>> Then we could easily relate the sk_drops with the SNMP counters.
>>
>> Something like that,
>>
>>     static void tcp_drop(struct sock *sk, struct sk_buff *skb, int mib_idx)
>>     {
>>         int segs = max_t(u16, 1, skb_shinfo(skb)->gso_segs);
>>
>>         atomic_add(segs, &sk->sk_drops);
>>         NET_ADD_STATS(sock_net(sk), mib_idx, segs);
>>         __kfree_skb(skb);
>>     }
>
> We had a discussion during netconf, and Brendan Gregg was working on
> an idea like that,
> so that distinct events could be traced/reported.
>

Oh yes, introducing a new tracepoint for it should be better.
trace_tcp_probe(sk, skb, mib_idx);

> I prefer letting Brendan submit his patch, which not only refactors
> things, but add new functionality.
>

OK.