RFR: 8329529: Serial: Move _saved_mark_word out of ContiguousSpace [v2]

[Albert Mingkun Yang]

On Thu, 4 Apr 2024 06:51:39 GMT, Guoxiong Li <gli at openjdk.org> wrote:

>> Hi all,
>> 
>> This patch removes the field `ContiguousSpace::_saved_mark_word` and its related methods, adds the corresponding fields to `DefNewGeneration` and `TenuredGeneration`, and moves the method `ContiguousSpace::oop_since_save_marks_iterate` to `Generation`. Many usages are adjusted as well.
>> 
>> An alternative way is add a class which extends the `ContiguousSpace` to place `_saved_mark_word` and its related methods. But this way would increase the class hierarchy. Not really know whether it deserves to do that.
>> 
>> The tests `make test-tier1_gc` passed locally. Thanks for taking the time to review.
>> 
>> Best Regards,
>> -- Guoxiong
>
> Guoxiong Li has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains four additional commits since the last revision:
> 
>  - Remove saved mark word of eden-space and from-space.
>  - Merge branch 'master' into SAVED_MARK_WORD
>  - Set saved mark word out of oop iteration.
>  - JDK-8329529

Marked as reviewed by ayang (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/18603#pullrequestreview-1979019854