RFR: 8324649: Shenandoah: refactor implementation of free set [v6]

[Kelvin Nilsen]

On Thu, 1 Feb 2024 07:15:51 GMT, Y. Srinivas Ramakrishna <ysr at openjdk.org> wrote:

>> Kelvin Nilsen has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Rename and comments for _capacity_of and _used_by
>
> src/hotspot/share/gc/shenandoah/shenandoahFullGC.cpp line 1069:
> 
>> 1067:     heap->collection_set()->clear();
>> 1068: 
>> 1069:     // Since Full GC directly manipulates top of certain regions, certain ShenandoahFreeSet abstractions may have been corrupted.
> 
> Instead of "may have been corrupted", which can be alarming and confusing, I'd state this as:
> 
> // Full GC doesn't use or maintain the ShenandoahFreeSet abstractions,
> // so we rebuild the free set from scratch following a Full GC.

I'm just going to remove that comment.  It raises concerns when none is necessary.  "Obviously", we need to rebuild the free set following a full gc.

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PR Review Comment: https://git.openjdk.org/jdk/pull/17561#discussion_r1477073747