- boot-time size the ipv4 flowtable and the maximum number of flows

- increase flow cleaning frequency and decrease flow caching time
  when near the flow limit
- stop allocating new flows when within 3% of maxflows don't start
  allocating again until below 12.5%

MFC after:	7 days

1 files changed, 14 insertions, 2 deletions

diff --git a/sys/netinet/ip_input.c b/sys/netinet/ip_input.c
index d91bcb0..8be51fb 100644
--- a/sys/netinet/ip_input.c
+++ b/sys/netinet/ip_input.c
@@ -327,8 +327,20 @@ ip_init(void)
 			"error %d\n", __func__, i);
 
 #ifdef FLOWTABLE
-	TUNABLE_INT_FETCH("net.inet.ip.output_flowtable_size",
-	    &V_ip_output_flowtable_size);
+	if (TUNABLE_INT_FETCH("net.inet.ip.output_flowtable_size",
+		&V_ip_output_flowtable_size)) {
+		if (V_ip_output_flowtable_size < 256)
+			V_ip_output_flowtable_size = 256;
+		if (!powerof2(V_ip_output_flowtable_size)) {
+			printf("flowtable must be power of 2 size\n");
+			V_ip_output_flowtable_size = 2048;
+		}
+	} else {
+		/*
+		 * round up to the next power of 2
+		 */
+		V_ip_output_flowtable_size = 1 << fls((1024 + maxusers * 64)-1);
+	}
 	V_ip_ft = flowtable_alloc("ipv4", V_ip_output_flowtable_size, FL_PCPU);
 #endif