diff --git a/weave b/weave
index b044a7cc..0b0985a9 100755
--- a/weave
+++ b/weave
@@ -147,8 +147,9 @@ docker_bridge_ip() {
 
 # the following borrows from https://github.com/jpetazzo/pipework
 
-# run args $2 $3 ... as a command in the network namespace of container $1
-# if an error is caused by container dying, swallow output from error
+# set $NETNS to the network namespace of container $1, and execute
+# args $2 $3 ... as a command.  If an error is caused by container
+# dying, swallow output from error.
 with_container_netns () {
     CONTAINER="$1"
     CONTAINER_PID=$(docker inspect --format='{{ .State.Pid }}' $CONTAINER)