RFR: 8338383: Implement JEP 491: Synchronize Virtual Threads without Pinning [v20]

[Patricio Chilano Mateo]

On Mon, 21 Oct 2024 09:55:53 GMT, Axel Boldt-Christmas <aboldtch at openjdk.org> wrote:

>> Patricio Chilano Mateo has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Rename oopCont + fix in JvmtiUnmountBeginMark
>
> src/hotspot/share/runtime/continuationFreezeThaw.cpp line 2538:
> 
>> 2536:   Method* m = hf.interpreter_frame_method();
>> 2537:   // For native frames we need to count parameters, possible alignment, plus the 2 extra words (temp oop/result handler).
>> 2538:   const int locals = !m->is_native() ? m->max_locals() : m->size_of_parameters() + frame::align_wiggle + 2;
> 
> Is it possible to have these extra native frame slots size be a named constant / enum value on `frame`? I think it is used in a couple of places.

I reverted this change and added an assert instead, since for native methods we always thaw the caller too, i.e. it will not be the bottom frame. I added a comment in the other two references for the extra native slots in continuationFreezeThaw_x86.inline.hpp.

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PR Review Comment: https://git.openjdk.org/jdk/pull/21565#discussion_r1823317839