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[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: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2005-07-05 15:21:10 -07:00
parent cb83199a29
commit 0d9901df62
1 changed files with 23 additions and 4 deletions
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27
net/ipv4/tcp_input.c
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@ -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,