Request for review (m) 8008966: NPG: Inefficient Metaspace counter functions cause large young GC regressions

[Jon Masamitsu]

Replace the use of a method that calculated the total capacity of
the Metaspaces by iterating over all the Metaspaces by maintaining
the sum of Metaspace capacities as the Metachunks are
allocated to each Metaspace.  Also maintain a sum for each
Metaspace as the Metachunks are allocated to that Metaspace.

Change should_expand() and compute_new_space() to
calculate quantities in bytes.

Remove calls to methods that calculated totals for
"used" and "free" by iterating over the Metaspaces
in product mode.  In some cases substitute the use
of capacity for used.

http://cr.openjdk.java.net/~jmasa/8008966/webrev.00/

Thanks.

Jon