tcp: add tcp_comp_sack_delay_ns sysctl

This per netns sysctl allows for TCP SACK compression fine-tuning.

Its default value is 1,000,000, or 1 ms to meet TSO autosizing period.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 2 deletions

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index cc2ac5346b92..6a1dae38c955 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -5113,13 +5113,13 @@ send_now:
         if (hrtimer_is_queued(&tp->compressed_ack_timer))
                 return;
 
-        /* compress ack timer : 5 % of rtt, but no more than 1 ms */
+        /* compress ack timer : 5 % of rtt, but no more than tcp_comp_sack_delay_ns */
 
         rtt = tp->rcv_rtt_est.rtt_us;
         if (tp->srtt_us && tp->srtt_us < rtt)
                 rtt = tp->srtt_us;
 
-        delay = min_t(unsigned long, NSEC_PER_MSEC,
+        delay = min_t(unsigned long, sock_net(sk)->ipv4.sysctl_tcp_comp_sack_delay_ns,
                       rtt * (NSEC_PER_USEC >> 3)/20);
         sock_hold(sk);
         hrtimer_start(&tp->compressed_ack_timer, ns_to_ktime(delay),