RFR: 8331721: Introduce CollectedHeap helper methods for any GC in progress

[Zhengyu Gu]

On Tue, 7 May 2024 14:33:26 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

> Continuation of [JDK-8331573](https://bugs.openjdk.org/browse/JDK-8331573). So far we only have a way to test for STW GCs. We would need these more generic sensing methods for [JDK-8331572](https://bugs.openjdk.org/browse/JDK-8331572).
> 
> This patch considers that there can be several concurrent GCs in progress. A notable example of that is Generational ZGC, where minor and major concurrent collections can run at the same time.
>  
> Initially, I thought to use `is_gc_active` name freed up by [JDK-8331573](https://bugs.openjdk.org/browse/JDK-8331573), but then I thought better of it. My concern would be that some backports might be confused about what `is_gc_active` name really means, depending on whether JDK-8331573 and this PR is backported or not. To avoid this confusion, I chose `is_any_gc_active` name instead.
> 
> This PR is somewhat open for bikeshedding about the names :)
> 
> Additional testing:
>  - [x] Linux AArch64 server fastdebug, `hotspot_gc`
>  - [ ] Linux AArch64 server fastdebug, `all`

Can you explain the purpose of this change? I assume you want to enable `oopMapCache` only when any gc is active, am I correct?

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PR Comment: https://git.openjdk.org/jdk/pull/19122#issuecomment-2098998387