RFR: 8325187: JVMTI GetThreadState says virtual thread is JVMTI_THREAD_STATE_INTERRUPTED when it no longer is [v2]

[David Holmes]

On Tue, 5 Mar 2024 06:16:04 GMT, Serguei Spitsyn <sspitsyn at openjdk.org> wrote:

>> Please, review this fix correcting the JVMTI  `RawMonitorWait()` implementation.
>> The `RawMonitorWait()` is using the the  `jt->is_interrupted(true)` to update the interrupt status of the interrupted waiting thread.  The issue is that when it calls `jt->is_interrupted(true)` to fetch and clear the `interrupt status` of the virtual thread, this information is not propagated to the `java.lang.Thread` instance.
>> In the `VirtualThread` class implementation the `interrupt status` for virtual thread is stored for both virtual and carrier threads. It is because the implementation of object monitors for virtual threads is based on pinning virtual threads, and so, always operates on carrier thread. The fix is to clear the interrupt status for both virtual and carrier  `java.lang.Thread` instances.
>> 
>> Testing:
>>  - tested with new test `hotspot/jtreg/serviceability/jvmti/vthread/InterruptRawMonitor` which is passed with the fix and failed without it
>>  - ran mach5 tiers 1-6
>
> Serguei Spitsyn has updated the pull request incrementally with one additional commit since the last revision:
> 
>   review: addressed a couple of comments on new test

I have to say that I don't understand how the behaviour of `RawMonitorWait` is any different to `ObjectMonitor::wait` when it comes to the use of the `is_interrupted(true)`.  ??? Is it simply that because we are in native code and we can immediately query the actual thread state that we can observe when the carrier and virtual thread states are transiently different?

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PR Comment: https://git.openjdk.org/jdk/pull/18093#issuecomment-1978090675