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

[Guoxiong Li]

On Fri, 5 Apr 2024 09:09:04 GMT, Albert Mingkun Yang <ayang at openjdk.org> wrote:

>>> I feel this doesn't belong to BOT. Can probably be dealt with in another ticket.
>> 
>> OK.
>> 
>> What about the method `G1BlockOffsetTable::verify`? Is it good to be moved to `HeapRegion` and change the name as `verify_bot`, `verify_BOT` or `verify_block_offset_table`?
>
> That sounds reasonable. (Should not be done in this PR though.)
> 
> (My experience with BOT is that they are almost never corrupted, so doing only checking-after-each-write is enough, sth like `ObjectStartArray::verify_for_block` -- there is possibly little value in verifying BOT in `HeapRegion::verify`. I wonder what others' opinions are.)

> I feel this doesn't belong to BOT. Can probably be dealt with in another ticket.

Filed https://bugs.openjdk.org/browse/JDK-8329767 to follow up.

> (My experience with BOT is that they are almost never corrupted, so doing only checking-after-each-write is enough, sth like `ObjectStartArray::verify_for_block` -- there is possibly little value in verifying BOT in `HeapRegion::verify`. I wonder what others' opinions are.)

The verifications of Serial and Parallel BOTs are similar. I agree that G1 should be adjusted. Filed https://bugs.openjdk.org/browse/JDK-8329771 to follow up.

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PR Review Comment: https://git.openjdk.org/jdk/pull/18634#discussion_r1553497806