there are no major to minor references that are not on the remembered
sets.
.TP
+\fBmod-union-consistency-check\fR
+Checks that the mod-union cardtable is consistent before each
+finishing major collection pause. This check is only applicable to
+concurrent major collectors.
+.TP
\fBcheck-mark-bits\fR
Checks that mark bits in the major heap are consistent at the end of
each major collection. Consistent mark bits mean that if an object is