Commit 0d9901df authored by David S. Miller's avatar David S. Miller
Browse files

[TCP]: Break out send buffer expansion test. 



This makes it easier to understand, and allows easier
tweaking of the heuristic later on.

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent cb83199a

net/ipv4/tcp_input.c

+23 −4
Original line number Diff line number Diff line
@@ -3300,6 +3300,28 @@ void tcp_cwnd_application_limited(struct sock *sk) 
	tp->snd_cwnd_stamp = tcp_time_stamp;

}



static inline int tcp_should_expand_sndbuf(struct sock *sk, struct tcp_sock *tp)

{

	/* If the user specified a specific send buffer setting, do

	 * not modify it.

	 */

	if (sk->sk_userlocks & SOCK_SNDBUF_LOCK)

		return 0;



	/* If we are under global TCP memory pressure, do not expand.  */

	if (tcp_memory_pressure)

		return 0;



	/* If we are under soft global TCP memory pressure, do not expand.  */

	if (atomic_read(&tcp_memory_allocated) >= sysctl_tcp_mem[0])

		return 0;



	/* If we filled the congestion window, do not expand.  */

	if (tp->packets_out >= tp->snd_cwnd)

		return 0;



	return 1;

}



/* When incoming ACK allowed to free some skb from write_queue,

 * we remember this event in flag SOCK_QUEUE_SHRUNK and wake up socket
@@ -3311,10 +3333,7 @@ static void tcp_new_space(struct sock *sk) 
{

	struct tcp_sock *tp = tcp_sk(sk);



	if (tp->packets_out < tp->snd_cwnd &&

	    !(sk->sk_userlocks & SOCK_SNDBUF_LOCK) &&

	    !tcp_memory_pressure &&

	    atomic_read(&tcp_memory_allocated) < sysctl_tcp_mem[0]) {

	if (tcp_should_expand_sndbuf(sk, tp)) {

 		int sndmem = max_t(u32, tp->rx_opt.mss_clamp, tp->mss_cache_std) +

			MAX_TCP_HEADER + 16 + sizeof(struct sk_buff),

		    demanded = max_t(unsigned int, tp->snd_cwnd,