RFR: 8318706: Implement JEP 423: Region Pinning for G1 [v10]

[Cheng Pan]

On Wed, 29 Nov 2023 10:02:31 GMT, Thomas Schatzl <tschatzl at openjdk.org> wrote:

>> Marked as reviewed by ayang (Reviewer).
>
> Thanks @albertnetymk @kstefanj @walulyai for your reviews! Given that the JEP is now targeted, I will integrate.
> 
> This has been a fairly long journey until today... :)

@tschatzl thanks for your excellent work! I know that JEP 423 targets JDK 22, but I wonder if this can be backported to JDK 21. For big data workloads like Apache Spark, we do see that G1 generally performs better than other GC algorithms, but one major issue is that it heavily uses JNI for compression/decompression (e.g. [zstd-jni](https://github.com/luben/zstd-jni/issues/346)), thus easy to OOM. 

I have tested some internal Spark jobs, which were easy to OOM on JDK 21, work well on JDK 22, but given that JDK 22 has been EOL, I would appreciate it if this could be landed on JDK 21

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PR Comment: https://git.openjdk.org/jdk/pull/16342#issuecomment-3177810965