RFR: 8364414: G1: Use simpler data structure for holding collection set candidates during calculation [v2]

[Albert Mingkun Yang]

On Thu, 31 Jul 2025 13:35:20 GMT, Thomas Schatzl <tschatzl at openjdk.org> wrote:

>> Hi all,
>> 
>>   please review this refactoring of the collection set choosing mechanism to use a lighter data structure: instead of an array of `G1CollectionSetCandidateInfo`s, use an array of `G1HeapRegion*` - we do not use the additional information provided by `G1CollectionSetCandidateInfo` at all during that process, and we copy the contents later anyway.
>> 
>> This reduces code complexity a bit (no need to extract the `G1HeapRegion*` from the struct) and reduces memory consumption a little as well.
>> 
>> Testing: gha
>> 
>> Thanks,
>>   Thomas
>
> Thomas Schatzl has updated the pull request incrementally with one additional commit since the last revision:
> 
>   * fix sort function

Marked as reviewed by ayang (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/26572#pullrequestreview-3075695649