RFR: 8358483: G1: Remove G1HeapRegionManager::num_available_regions

[Sangheon Kim]

On Wed, 4 Jun 2025 13:44:25 GMT, Ivan Walulya <iwalulya at openjdk.org> wrote:

>> Simple cleanup of moving an API from `G1HeapRegionManager` to `G1CollectedHeap`.
>> 
>> Test: tier1
>
> I would advocate for moving more APIs into `G1HeapRegionManager` instead of adding more to `G1CollectedHeap`.

I agree with @walulyai .
Adding convenient APIs on `G1CollectedHeap` is a matter of preference. But I dislike removing a basic API from `G1HeapRegionManager`. Maybe we disagree whether `num_available_regions() ` is a basic API or not?

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PR Comment: https://git.openjdk.org/jdk/pull/25611#issuecomment-2941904091