RFR: 8290525: Move HeapRegion::_compaction_top to G1FullCollector

[Kim Barrett]

On Tue, 19 Jul 2022 15:47:01 GMT, Thomas Schatzl <tschatzl at openjdk.org> wrote:

> Hi all,
> 
>   can I have reviews for this change that moves `HeapRegion::_compaction_top` into the `G1FullCollector` class; my reasoning is that these values are transient temporary values only ever useful for the full collection algorithm, basically results of the application of the algorithm, that are otherwise unused. This makes `HeapRegion` a bit easier to understand/read.
> 
> Testing: tier1-3
> 
> Thanks,
>   Thomas

Looks good.  Just one minor formatting nit.

src/hotspot/share/gc/g1/g1FullCollector.hpp line 93:

> 91:   G1FullGCHeapRegionAttr _region_attr_table;
> 92: 
> 93:   HeapWord*volatile *_compaction_tops;

Spacing in the type is strange.  `HeapWord* volatile* _compaction_tops;` is (I think) more usual for our code.

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Marked as reviewed by kbarrett (Reviewer).

PR: https://git.openjdk.org/jdk/pull/9560