RFR: 8361099: Shenandoah: Improve heap lock contention by using CAS for memory allocation [v14]

[Xiaolong Peng]

On Wed, 7 Jan 2026 23:09:16 GMT, Xiaolong Peng <xpeng at openjdk.org> wrote:

>> Put the comments describing functions in the .hpp file, where they are currently.  But we need to enhance those comments.
>
> I have added comments on those functions, I'll keep adding more for those missing comments; meanwhile I am trying to avoid excessive comment, pleas point out if any of the comments is not clear.

I have removed the branch handling  _alloc_region_count == 0, also updated comments.

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PR Review Comment: https://git.openjdk.org/jdk/pull/26171#discussion_r2696214206