RFR: 8338383: Implement JEP 491: Synchronize Virtual Threads without Pinning

[Patricio Chilano Mateo]

On Sat, 2 Nov 2024 02:41:44 GMT, Fei Yang <fyang at openjdk.org> wrote:

>> Changed.
>
> Note that `frame::sender_sp_offset` is 0 instead of 2 on linux-riscv64, which is different from aarch64 or x86-64. So I think we should revert this change: https://github.com/openjdk/jdk/pull/21565/commits/12213a70c1cf0639555f0f302237fd012549c4dd. @pchilano : Could you please help do that? 
> 
> (PS: `hotspot_loom & jdk_loom` still test good with latest version after locally reverting https://github.com/openjdk/jdk/pull/21565/commits/12213a70c1cf0639555f0f302237fd012549c4dd)

Sorry, I also thought it matched the aarch64 one without checking. @RealFYang should I change it for `hf.sp() + frame::link_offset` or just leave it as it was?

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PR Review Comment: https://git.openjdk.org/jdk/pull/21565#discussion_r1828190876