diff --git a/lib/moodlelib.php b/lib/moodlelib.php
index 8af6ff0f4a8..0916144055d 100644
--- a/lib/moodlelib.php
+++ b/lib/moodlelib.php
@@ -6601,7 +6601,9 @@ function moodle_request_shutdown() {
 
     // initially, we are only ever called under apache 
     // but check just in case 
-    if (function_exists('apache_child_terminate') && function_exists('memory_get_usage')) {
+    if (function_exists('apache_child_terminate') 
+        && function_exists('memory_get_usage')
+        && ini_get_bool('child_terminate')) {
         if (empty($CFG->apachemaxmem)) {
             $CFG->apachemaxmem = 25000000; // default 25MiB
         }