RFR: 8342382: Implement JEP 522: G1 GC: Improve Throughput by Reducing Synchronization [v59]

[Thomas Schatzl]

On Thu, 11 Sep 2025 07:24:13 GMT, Thomas Schatzl <tschatzl at openjdk.org> wrote:

>> Thomas Schatzl has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   * walulyai review
>
> That test failure in windows-x64 is a shenandoah timeout that looks unrelated.

> @tschatzl : Hi, would you mind adding a small cleanup change for riscv? This also adds back the assertion about the registers. Still test good on linux-riscv64 platform. [riscv-addon.diff.txt](https://github.com/user-attachments/files/22356611/riscv-addon.diff.txt)

This is the `end` -> `count` transformation in the barrier I suggested earlier for RISC-V, isn't it? Thanks for contributing that, but would you mind me holding off this until @theRealAph acks that similar change for aarch64? It would be unfortunate imo if the implementations diverge too much.

-------------

PR Comment: https://git.openjdk.org/jdk/pull/23739#issuecomment-3296253540