total_fragmentation_bytes metric is probably misleading

By running "cbstats memory" and "cbstats allocator" I feel like total_fragmentation_bytes corresponds to "Bytes in central cache freelist".

IMHO it makes more sense to consider as fragmented bytes any difference between RSS and actually used memory (mem_used or "Bytes in use by application"). For instance, "Bytes in page heap freelist" are not considered as "fragmentation bytes" and this is not quite correct.

At least providing documentation regarding those metrics will help a lot.