RFR: 8334445: Parallel: Decouple maximum compaction from SoftReference clearing [v3]

[Liang Mao]

On Mon, 8 Jul 2024 08:36:53 GMT, Albert Mingkun Yang <ayang at openjdk.org> wrote:

>> src/hotspot/share/gc/parallel/psParallelCompact.hpp line 741:
>> 
>>> 739:   static void fill_dense_prefix_end(SpaceId id);
>>> 740: 
>>> 741:   static void summary_phase();
>> 
>> After this change, will the clear-soft-refs full gc become non-maximum from maximum compact and affect the current behavior?
>
> After the change, clear-soft-refs and max-compaction (not leaving any deadwood) will be two independent decisions, which can result into externally visible change-of-behavior, e.g. shorter full-gc in certain cases, since max-compaction is trading time for space.

I just thought the behavior change was significant. If it is expected, it looks good.

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PR Review Comment: https://git.openjdk.org/jdk/pull/19763#discussion_r1668225142