RFR: 8338383: Implement JEP 491: Synchronize Virtual Threads without Pinning [v19]

[Serguei Spitsyn]

On Wed, 30 Oct 2024 20:10:03 GMT, Patricio Chilano Mateo <pchilanomate at openjdk.org> wrote:

>> src/hotspot/share/runtime/continuation.cpp line 88:
>> 
>>> 86:       if (_target->has_async_exception_condition()) {
>>> 87:         _failed = true;
>>> 88:       }
>> 
>> Q: I wonder why the failed conditions are not checked before the `start_VTMS_transition()` call. At least, it'd be nice to add a comment about on this.
>
> These will be rare conditions so I don't think it matters to check them before. But I can move them to some method that we call before and after if you prefer.

Just wanted to understand what needs to be checked after the start_VTMS_transition() call.
You are right, we need to check the `_thread->has_async_exception_condition()` after the call.
The pending `popframe` and  `earlyret` can be checked before as I understand.
I'm not sure there is a real need in double-checking before and after. So, let's keep it as it is for now.

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PR Review Comment: https://git.openjdk.org/jdk/pull/21565#discussion_r1824134075