[TCP]: Do not purge sk_forward_alloc entirely in tcp_delack_timer().
Otherwise we beat heavily on the global tcp_memory atomics
when all of the sockets in the system are slowly sending
perioding packet clumps.
Noticed and suggested by Eric Dumazet.
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c
index 17931be..803d758 100644
--- a/net/ipv4/tcp_timer.c
+++ b/net/ipv4/tcp_timer.c
@@ -186,7 +186,7 @@
goto out_unlock;
}
- sk_mem_reclaim(sk);
+ sk_mem_reclaim_partial(sk);
if (sk->sk_state == TCP_CLOSE || !(icsk->icsk_ack.pending & ICSK_ACK_TIMER))
goto out;