diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index 29a93518bf18acc7d9a0a3ac443abd03662e3792..3cce8ea6b139ddc013253f0bc129e5c7052f19d6 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -65,6 +65,12 @@ neigh/default/gc_thresh1 - INTEGER
 	purge entries if there are fewer than this number.
 	Default: 128
 
+neigh/default/gc_thresh2 - INTEGER
+	Threshold when garbage collector becomes more aggressive about
+	purging entries. Entries older than 5 seconds will be cleared
+	when over this number.
+	Default: 512
+
 neigh/default/gc_thresh3 - INTEGER
 	Maximum number of neighbor entries allowed.  Increase this
 	when using large numbers of interfaces and when communicating