From: David S. Miller <davem@davemloft.net>
Date: Sun, 28 Sep 2014 20:35:49 +0000 (-0400)
Subject: Merge branch 'tcp_skb_cb'
X-Git-Tag: v3.18-rc1~115^2~133
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=dc83d4d8f6c897022c974a00769b7a6efee6aed8;p=linux.git

Merge branch 'tcp_skb_cb'

Eric Dumazet says:

====================
tcp: better TCP_SKB_CB layout

TCP had the assumption that IPCB and IP6CB are first members of skb->cb[]

This is fine, except that IPCB/IP6CB are used in TCP for a very short time
in input path.

What really matters for TCP stack is to get skb->next,
TCP_SKB_CB(skb)->seq, and TCP_SKB_CB(skb)->end_seq in the same cache line.

skb that are immediately consumed do not care because whole skb->cb[] is
hot in cpu cache, while skb that sit in wocket write queue or receive queues
do not need TCP_SKB_CB(skb)->header at all.

This patch set implements the prereq for IPv4, IPv6, and TCP to make this
possible. This makes TCP more efficient.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
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dc83d4d8f6c897022c974a00769b7a6efee6aed8