RFR: 8338383: Implement JEP 491: Synchronize Virtual Threads without Pinning [v3]

[Patricio Chilano Mateo]

On Tue, 22 Oct 2024 06:27:26 GMT, David Holmes <dholmes at openjdk.org> wrote:

>> Patricio Chilano Mateo has updated the pull request incrementally with six additional commits since the last revision:
>> 
>>  - Fix comments in objectMonitor.hpp
>>  - Move frame::saved_thread_address() to platform dependent files
>>  - Fix typo in jvmtiExport.cpp
>>  - remove usage of frame::metadata_words in possibly_adjust_frame()
>>  - Fix comments in c2 locking paths
>>  - Revert and simplify changes to c1_Runtime1 on aarch64 and riscv
>
> src/hotspot/share/runtime/objectMonitor.hpp line 47:
> 
>> 45: // ParkEvent instead.  Beware, however, that the JVMTI code
>> 46: // knows about ObjectWaiters, so we'll have to reconcile that code.
>> 47: // See next_waiter(), first_waiter(), etc.
> 
> This to-do is likely no longer relevant with the current changes.

Removed.

> src/hotspot/share/runtime/objectMonitor.hpp line 288:
> 
>> 286:   // Returns true if this OM has an owner, false otherwise.
>> 287:   bool      has_owner() const;
>> 288:   int64_t   owner() const;  // Returns null if DEFLATER_MARKER is observed.
> 
> null is not an int64_t value.

Changed to NO_OWNER.

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PR Review Comment: https://git.openjdk.org/jdk/pull/21565#discussion_r1811596618
PR Review Comment: https://git.openjdk.org/jdk/pull/21565#discussion_r1811596855