diff --git a/Documentation/networking/xfrm_sysctl.txt b/Documentation/networking/xfrm_sysctl.txt
new file mode 100644
index 0000000..5bbd167
--- /dev/null
+++ b/Documentation/networking/xfrm_sysctl.txt
@@ -0,0 +1,4 @@
+/proc/sys/net/core/xfrm_* Variables:
+
+xfrm_acq_expires - INTEGER
+	default 30 - hard timeout in seconds for acquire requests