tcp: allow one skb to be received per socket under memory pressure
While testing tight tcp_mem settings, I found tcp sessions could be
stuck because we do not allow even one skb to be received on them.
By allowing one skb to be received, we introduce fairness and
eventuallu force memory hogs to release their allocation.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 093779f..40c4359 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -4507,10 +4507,12 @@
if (eaten <= 0) {
queue_and_out:
- if (eaten < 0 &&
- tcp_try_rmem_schedule(sk, skb, skb->truesize))
- goto drop;
-
+ if (eaten < 0) {
+ if (skb_queue_len(&sk->sk_receive_queue) == 0)
+ sk_forced_mem_schedule(sk, skb->truesize);
+ else if (tcp_try_rmem_schedule(sk, skb, skb->truesize))
+ goto drop;
+ }
eaten = tcp_queue_rcv(sk, skb, 0, &fragstolen);
}
tcp_rcv_nxt_update(tp, TCP_SKB_CB(skb)->end_seq);