doc: mention more changes needed to use huge pages

Report by Laurence Parry

diff --git a/doc/src/sgml/runtime.sgml b/doc/src/sgml/runtime.sgml
index 639b288e0629c99be4409ae9d40d3de0414f5d8a..026850a1cf5547e56c0a540679e15c4ad3f76d8a 100644 (file)
--- a/doc/src/sgml/runtime.sgml
+++ b/doc/src/sgml/runtime.sgml
@@ -1360,6 +1360,13 @@ $ <userinput>sysctl -w vm.nr_hugepages=3170</userinput>
     this setting through reboots.
    </para>
 
+   <para>
+    It is also necessary to give the database server operating system
+    user permission to use huge pages by setting
+    <varname>vm.hugetlb_shm_group</> via <application>sysctl</>, and
+    permission to lock memory with <command>ulimit -l</>.
+   </para>
+
    <para>
     The default behavior for huge pages in
     <productname>PostgreSQL</productname> is to use them when possible and