RFR: 8329603: G1: Merge G1BlockOffsetTablePart into G1BlockOffsetTable [v2]

[Guoxiong Li]

On Thu, 4 Apr 2024 17:34:08 GMT, Albert Mingkun Yang <ayang at openjdk.org> wrote:

>> Guoxiong Li has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Use a simple/unified BOT.
>
> src/hotspot/share/gc/g1/g1BlockOffsetTable.hpp line 56:
> 
>> 54: 
>> 55:   // The region that owns this BOT.
>> 56:   HeapRegion* _hr;
> 
> Is it possible to have a single bot in `G1CollectedHeap` and every region has a pointer to that?

I marked the fields `_offset_base` and `_reserved` as `non-static`, removed the field `_hr` and shared a simple/unified BOT for all the heap regions. Since few methods need the heap region, I used the heap region as method parameter in such methods.

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PR Review Comment: https://git.openjdk.org/jdk/pull/18634#discussion_r1553054067