RFR: 8312498: Thread::getState and JVM TI GetThreadState should return TIMED_WAITING virtual thread is timed parked

[Serguei Spitsyn]

On Fri, 21 Jul 2023 18:01:45 GMT, Alan Bateman <alanb at openjdk.org> wrote:

> Thread::getState is an API for monitoring and management purposes to report the thread state. If a virtual thread is parked with LockSupport.parkNanos, its state is reported as  WAITING when it should be TIMED_WAITING. JVM TI GetThreadState has the same issue in that it returns JVMTI_THREAD_STATE_WAITING_INDEFINITELY instead of the JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT bit set. Not a very visible issue because JDWP maps both states to "WAIT" but it may be noticed by tools using other JVM TI agents.
> 
> The change is straight-forward, it's just additional state bit to indicate that park is timed. The existing virtual/ThreadAPI.java test is expanded to this scenario. A new test is added for JVM TI GetThreadState to test waiting/timed-waited cases (including pinned) as test coverage seems patchy here.

test/hotspot/jtreg/serviceability/jvmti/vthread/GetThreadState/GetThreadStateTest.java line 133:

> 131:         } finally {
> 132:             thread.join();
> 133:             Reference.reachabilityFence(lock);

It would be nice to add a short comment why this is needed.

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PR Review Comment: https://git.openjdk.org/jdk/pull/14978#discussion_r1274681311