From mboxrd@z Thu Jan  1 00:00:00 1970
From: Eric Dumazet <eric.dumazet@gmail.com>
Subject: Re: [PATCH net-next] tcp: use an RB tree for ooo receive queue
Date: Wed, 07 Sep 2016 15:32:49 -0700
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Cc: David Miller <davem@davemloft.net>,
        netdev <netdev@vger.kernel.org>,
        Yaogong Wang <wygivan@google.com>,
        Yuchung Cheng <ycheng@google.com>,
        Neal Cardwell <ncardwell@google.com>,
        Ilpo =?ISO-8859-1?Q?J=E4rvinen?= <ilpo.jarvinen@helsinki.fi>
To: Stephen Hemminger <stephen@networkplumber.org>
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On Wed, 2016-09-07 at 15:26 -0700, Stephen Hemminger wrote:

> How much does this grow the size of tcp socket structure?

This actually shrinks it by 8 bytes, or more on debug kernels where
sizeof(spinlock_t) > 4

Before :

struct sk_buff_head out_of_order_queue;  // At least 24 bytes on 64bit 


After :

2 pointers ( 16 bytes on 64bit )