The existing implementation keeps redundant copies of amounts of memory used, allocated, empty/unaffiliated. One copy is maintained by ShenandoahGeneration. The other copy is maintained by ShenandoahFreeSet.

Occasional assertions confirm the two copies of this information are consistent. However, rare assertion checks fail, because the two sets of books are updated at different times, using different synchronization mechanisms.

Besides eliminating these rare assertion failures, the other benefit of this change is to eliminate the overhead associated with keeping redundant sets of information.