RFR: 8305895: Implement JEP 450: Compact Object Headers (Experimental) [v8]

[Stefan Karlsson]

On Fri, 13 Sep 2024 11:10:58 GMT, Thomas Schatzl <tschatzl at openjdk.org> wrote:

>> That bug doesn't fix all cases where the the length field is modified.
>
> Which ones are remaining? JDK-8337709 implemented the same change for G1 GC before JDK-8311163.
> 
> The full collectors/g1 marking do not modify the length fields but have multiple separate queues which is a different issue. It will also be handled by the new `PartialArrayTaskStepper`, but should be of no concern here.
> 
> If I am not missing some case, this whole method is unnecessary now.

If you've already fixed this for GC then I agree that we could remove this.

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PR Review Comment: https://git.openjdk.org/jdk/pull/20677#discussion_r1758805418