RFR: 8373272: Genshen: ShenandoahOldGenerationTest fails after JDK-8373056

[Xiaolong Peng]

On Mon, 8 Dec 2025 19:40:10 GMT, William Kemper <wkemper at openjdk.org> wrote:

>> ShenandoahOldGeneration::configure_plab_for_current_thread has been updated to only handle plab req, which is a behavior change, but ShenandoahOldGenerationTest was not updated to match the behavior change, causing the test to fail.
>> 
>> The two failing unit tests of ShenandoahOldGenerationTest have been removed in this PR since the behavior being verified with them is no longer in configure_plab_for_current_thread, meanwhile one more unit test is added to verify the behavior of `expend_promoted`
>> 
>> ### Test
>> - [x] CONF=macosx-aarch64-server-fastdebug make test TEST=gtest
>> - [ ] CONF=macosx-aarch64-server-fastdebug make test TEST=hotspot_gc_shenandoah
>
> src/hotspot/share/gc/shenandoah/shenandoahOldGeneration.cpp line 196:
> 
>> 194: }
>> 195: 
>> 196: void
> 
> I would revert this back to asserting its never called for a shared allocation and delete the test (but keep the new `test_expend_promoted_should_increase_expended`).

Thanks, I also prefer this approach.

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PR Review Comment: https://git.openjdk.org/jdk/pull/28706#discussion_r2599931175