diff --git a/man7/cgroups.7 b/man7/cgroups.7
index 0627206c8..617c9ac9f 100644
--- a/man7/cgroups.7
+++ b/man7/cgroups.7
@@ -910,6 +910,10 @@ can enable controllers (that are present in
 in order to further redistribute resources at lower levels in the subtree.
 (As an alternative to changing the ownership of this file,
 the delegater might instead add selected controllers to this file.)
+.TP
+.IR /dlgt_grp/cgroup.threads
+Changing the ownership of this file is necessary if a threaded subtree
+is being delegated (see the description of "thread mode", below).
 .PP
 The delegater should
 .I not