RFR: 8306687: Relax memory ordering constraints on metaspace atomic counters

[Yumin Qi]

On Mon, 24 Apr 2023 13:15:09 GMT, Zhengyu Gu <zgu at openjdk.org> wrote:

> Metaspace atomic counter (`SizeAtomicCounter`) is used to track used `class` and `nonclass` metaspace sizes, they are pure counters and only need atomic guarantee.
> 
> Test:
> - [x] hotspot_metaspace MacOSX M1
> - [x] hotspot_metaspace Linux x86_64
> - [x] hotspot_metaspace Linux x86_32

LGTM.

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Marked as reviewed by minqi (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/13618#pullrequestreview-1400169525