RFR: 8351091: Shenandoah: global marking context completeness is not accurately maintained [v4]

[Xiaolong Peng]

On Fri, 7 Mar 2025 00:58:15 GMT, Y. Srinivas Ramakrishna <ysr at openjdk.org> wrote:

>> Question: Does Shenandoah promote region in global cycles? the gc_generation might be global if so.
>
> Good point. I don't see any reason promotions should be verboten in global cycles. cc @earthling-amzn ?
> 
> If that is indeed the case, a clean separation and maintenance of completeness of marking for global generation, and use of `_heap->gc_generation()` would make sense to me.

Thanks for the confirmation, I added assert as below since it gc_generation could be global :


assert(!_heap->gc_generation()->is_old(), "Sanity check");

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PR Review Comment: https://git.openjdk.org/jdk/pull/23886#discussion_r1984253086