From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Miller <davem@davemloft.net>
Subject: Re: [PATCH] icmp: No need to call sk_write_space()
Date: Mon, 05 Oct 2009 00:12:10 -0700 (PDT)
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From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Fri, 25 Sep 2009 00:16:51 +0200

> We can make icmp messages tx completion callback a litle bit faster.
> 
> Setting SOCK_USE_WRITE_QUEUE sk flag tells sock_wfree() to
> not call sk_write_space() on a socket we know no thread is posssibly
> waiting for write space. (on per cpu kernel internal icmp sockets only)
> 
> This avoids the sock_def_write_space() call and 
> read_lock(&sk->sk_callback_lock)/read_unlock(&sk->sk_callback_lock) calls
> as well.
> 
> We avoid three atomic ops.
> 
> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>

Applied to net-next-2.6