[jdk25u] RFR: 8370048: Shenandoah: Deprecated ShenandoahPacing option

[Y. Srinivas Ramakrishna]

On Thu, 16 Oct 2025 23:41:16 GMT, William Kemper <wkemper at openjdk.org> wrote:

> This is not a direct backport. We removed `ShenandoahPacing` from JDK26. This was an experimental option, so we did not formally deprecate it at the time. However, in hindsight, we feel it would be a better user experience in 25 to receive a deprecation warning if the option is given.
> 
> Testing:
> 
> [0] % ./build/linux-x86_64-server-release/jdk/bin/java -XX:+UseShenandoahGC -XX:+UnlockExperimentalVMOptions -XX:-ShenandoahPacing -version 
> OpenJDK 64-Bit Server VM warning: Option ShenandoahPacing was deprecated in version 25.0 and will likely be removed in a future release.

Thank you for cleaning up _mea culpa_!

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Marked as reviewed by ysr (Reviewer).

PR Review: https://git.openjdk.org/jdk25u/pull/321#pullrequestreview-3347492012