RFR: JDK-8302385: Remove MetaspaceReclaimPolicy=none

[David Holmes]

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)

The removal looks clean to me too. Thanks.

Not sure how that missing license header in the test was not previously detected!

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Marked as reviewed by dholmes (Reviewer).

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