Have MacMap throttle itself to 64 switches at a time to fend off memory starvation

git-svn-id: https://svn.code.sf.net/p/xcat/code/xcat-core/branches/2.7@12006 8638fb3e-16cb-4fca-ae20-7b5d299a9bcd

perl-xCAT/xCAT/MacMap.pm

@@ -337,6 +337,9 @@ sub refresh_table {
     if ($checked_pairs{$entry->{switch}}) {
       next;
     }
+    while($children > 64) {
+    	$self->handle_output($inputs);
+    }
     $checked_pairs{$entry->{switch}}=1;
     pipe my $child,my $parent;
     $child->autoflush(1);