RFR: 8313332: Simplify lazy jmethodID cache in InstanceKlass [v2]

[Serguei Spitsyn]

On Wed, 3 Apr 2024 13:25:36 GMT, Coleen Phillimore <coleenp at openjdk.org> wrote:

>> This change simplifies the code that grows the jmethodID cache in InstanceKlass.  Instead of lazily, when there's a rare request for a jmethodID for an obsolete method, the jmethodID cache is grown during the RedefineClasses safepoint.  The InstanceKlass's jmethodID cache is lazily allocated when there's a jmethodID allocated, so not every InstanceKlass has a cache, but the growth now only happens in a safepoint.  This code will become racy with the potential change for deallocating jmethodIDs.
>> 
>> Tested with tier1-4, vmTestbase/nsk/jvmti java/lang/instrument tests (in case they're not in tier1-4).
>
> Coleen Phillimore has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Refactoring suggested by Serguei.

Looks good to me. Nice simplification.

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Marked as reviewed by sspitsyn (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/18549#pullrequestreview-1977358735