RFR: JDK-8302385: Remove MetaspaceReclaimPolicy=none

[Ioi Lam]

On Tue, 14 Feb 2023 10:26:02 GMT, Thomas Stuefe <stuefe at openjdk.org> wrote:

> This patch removes the "MetaspaceReclaimPolicy=none" mode. It had been a safety measure when JEP-387 came out, but it has never really been needed. Since it adds complexity (especially in tests) I'd like to get rid of it.
> 
> For more details, please see the reasoning in CSR [JDK-8302130](https://bugs.openjdk.org/browse/JDK-8302130).
> 
> -------
> 
> Tests:
> - I manually ran metaspace tests (see test group "hotspot_metaspace") on linux x64 (release, fastdebug) and x86 (fastdebug) 
> - GHAs are scheduled.
> 
> -------
> 
> Reviewer hint:
> 
> Removing the "none" Policy basically hardcodes the behavioral settings to:
> 
> Settings::**uncommit_free_chunks** => **true**; (as in, we always do reclaim upon classloader death)
> Settings::**new_chunks_are_fully_committed** => **false**; (as in, newly allocated chunks are only committed as far as needed)

I looked at the diff with whitespace turned off. It seems to be a clean removal of the `none` policy.

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Marked as reviewed by iklam (Reviewer).

PR: https://git.openjdk.org/jdk/pull/12554