CRON menu memory exhausted issue

After running the patch above at some sites with good results, it turned out one site (with a lots of logging) complained that variable $uid was unknown.
Therefore i fixed it by adding global $user and changed $uid to $user->hid like this

Sometimes it turns out that CRON in drupal requires a LOT of memory, often the problem comes up as a memory exhausted message in menu.inc

This turns out to be because the menu_rebuild is called many times when its actually is only needed to be called once.

This is my quick-fix and i know hacking drupal core isn't the way to go

--- includes/menu.inc.old 2015-02-11 11:01:12.411387934 +0000
+++ includes/menu.inc 2015-02-11 11:10:16.204995356 +0000
@@ -2717,6 +2717,16 @@
return FALSE;
}

+// ****************************
+// Added by arne@hortell.se
+// Found it in admin menus
+
+ $was_flushed = &drupal_static(__FUNCTION__, array());
+ global $user;
+ if (isset($was_flushed[$user->uid])) {
+ return FALSE;
+ }
+// *****************************
+
$transaction = db_transaction();

try {
@@ -2727,6 +2737,11 @@
menu_cache_clear_all();
_menu_clear_page_cache();

+// ****************************
+// Added by arne@hortell.se
+ global $user;
+ $was_flushed[$user->uid] = TRUE;
+// *****************************
+
if (defined('MAINTENANCE_MODE')) {
variable_set('menu_rebuild_needed', TRUE);
}

I really don't know but the $uid originally came from the admin menu where i found that they prevent rebuilding the menu lot of times.
The thing with the lock is when multiple modules call to rebuild the menu, they surly get locked from OTHER users but the single user which executes it serially does not get aware that the menu already was rebuild and therefore does it again.