RFR: 8317466: Enable interpreter oopMapCache for concurrent GCs [v2]

[Zhengyu Gu]

On Thu, 19 Oct 2023 16:11:56 GMT, Leela Mohan Venati <duke at openjdk.org> wrote:

>> src/hotspot/share/gc/shenandoah/shenandoahVMOperations.cpp line 64:
>> 
>>> 62:   OopMapCache::cleanup_old_entries();
>>> 63: }
>>> 64: 
>> 
>> Do you think, VM_ShenandoahFinalMarkStartEvac walks the stack roots.  If yes, i recommend adding OopMapCache::cleanup_old_entries() in  VM_ShenandoahOperation::doit_epilogue().  And this would make the change simple and also revert the change in this [PR](https://github.com/openjdk/jdk/pull/15921)
>
> I stand corrected. 
> 
> My question is still relevant 
>>> Do you think, VM_ShenandoahFinalMarkStartEvac walks the stack roots.
> 
> My recommendation is incorrect.

No, `VM_ShenandoahFinalMarkStartEvac ` does not walk the stack roots, it signals the end of mark phase.

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PR Review Comment: https://git.openjdk.org/jdk/pull/16074#discussion_r1369175629