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From: David Miller <davem@davemloft.net>
Subject: Re: [PATCH net-next-2.6] net: ip_queue_rcv_skb() helper
Date: Wed, 28 Apr 2010 15:39:10 -0700 (PDT)
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From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Thu, 29 Apr 2010 00:22:44 +0200

> Next patch will try to not touch dst refcount in input path (previously
> attempted in July 2009)
> Ref : http://kerneltrap.org/mailarchive/linux-netdev/2009/7/22/6248753

Yes, I remember this.

> [PATCH net-next-2.6] net: ip_queue_rcv_skb() helper
> 
> When queueing a skb to socket, we can immediately release its dst if
> target socket do not use IP_CMSG_PKTINFO.
> 
> tcp_data_queue() can drop dst too.
> 
> This to benefit from a hot cache line and avoid the receiver, possibly
> on another cpu, to dirty this cache line himself.
> 
> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>

Pretty soon the whole receive path will be "read mostly" :-)

Applied, thanks Eric.