RFR: 8352508: [Redo] G1: Pinned regions with pinned objects only reachable by native code crash VM [v4]

[Albert Mingkun Yang]

On Mon, 24 Mar 2025 11:37:57 GMT, Thomas Schatzl <tschatzl at openjdk.org> wrote:

>> Hi all,
>> 
>>   please review this change that re-implements the fix for [JDK-8351921](https://bugs.openjdk.org/browse/JDK-8351921); in that fix we (think we) forgot to consider the same situation with optional regions.
>> 
>> I.e. the previous fix only fixed the situation occurring during initial evacuation, however as we add regions due to optional evacuation, the same situation can still happen.
>> 
>> So this change adds some work to every evacuation phase that marks all pinned regions in the current collection set as evacuation failed/pinned instead of only doing this work once in the pre evacuation phase.
>> 
>> As for testing, it is extremely hard to induce a situation where there is a pinned region with no apparent live objects in an optional collection set, so I gave up and just added the original test again.
>> 
>> Testing: gha, test
>> 
>> Thanks,
>>   Thomas
>
> Thomas Schatzl has updated the pull request incrementally with one additional commit since the last revision:
> 
>   * improve test to also test empty pinned humongous regions

Marked as reviewed by ayang (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/24147#pullrequestreview-2721084350