From mboxrd@z Thu Jan  1 00:00:00 1970
From: Joe Perches <joe@perches.com>
Subject: Re: [PATCH net-next] tcp: tcp_sendmsg() page recycling
Date: Sun, 04 Dec 2011 09:20:53 -0800
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Cc: David Miller <davem@davemloft.net>, netdev <netdev@vger.kernel.org>
To: Eric Dumazet <eric.dumazet@gmail.com>
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On Sun, 2011-12-04 at 18:05 +0100, Eric Dumazet wrote:
> If our TCP_PAGE(sk) is not shared (page_count() == 1), we can set page
> offset to 0.
[]
> diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
[]
> @@ -1009,7 +1009,12 @@ new_segment:
>  				int merge = 0;
>  				int i = skb_shinfo(skb)->nr_frags;
>  				struct page *page = TCP_PAGE(sk);
> -				int off = TCP_OFF(sk);
> +				int off;
> +
> +				if (page && page_count(page) == 1)
> +					TCP_OFF(sk) = 0;
> +
> +				off = TCP_OFF(sk);

This might be clearer and take one less indirection as

				if (page && page_count(page) == 1) {
					TCP_OFF(sk) = 0;
					off = 0;
				} else {
					off = 0;
				}

or maybe

				if (page && page_count(page) == 1)
					off = TCP_OFF(sk) = 0;
				else
					off = 0;

And maybe the TCP_OFF and TCP_PAGE macros should be removed.