[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>
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index b948e4e..2ef2f35 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -3300,6 +3300,28 @@
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 @@
{
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,