[JDK19] JVMTI VirtualThread[Mount|UnMount] Events

[babsingh]

JVMTI VirtualThreadMount and VirtualThreadUnMount events are part of the JVMTI Extension API, which is not covered by the JVMTI documentation. So, they don't need to be supported for the current Java 19 milestone.

Their implementation will be similar to the VirtualThreadStart and VirtualThreadEnd events. VirtualThreadStart and VirtualThreadEnd events are only triggered during the first mount and last unmount respectively. But, VirtualThreadMount and VirtualThreadUnMount events will be triggered on each mount and unmount respectively.

The following JVMTI serviceability tests will need to be disabled until support for the VirtualThreadMount and VirtualThreadUnMount events is introduced:

vthread/BreakpointInYieldTest/libBreakpointInYieldTest.cpp
vthread/MethodExitTest/libMethodExitTest.cpp
vthread/NullAsCurrentThreadTest/libNullAsCurrentThreadTest.cpp
vthread/VThreadTest/libVThreadTest.cpp
vthread/VThreadUnsupportedTest/libVThreadUnsupportedTest.cpp

[babsingh]

fyi @fengxue-IS @tajila @pshipton @JasonFengJ9

[pshipton]

Is somebody taking care of excluding those tests?

[babsingh]

@fengxue-IS Can you confirm if you plan to exclude the above tests while enabling the fixed tests?

[fengxue-IS]

@fengxue-IS Can you confirm if you plan to exclude the above tests while enabling the fixed tests?

yes, I've created https://github.com/fengxue-IS/aqa-tests/tree/loom3 to address this, still testing to make sure it covers all cases

[babsingh]

@dipak-bagadiya Can you look at this issue?

The solution will be similar to the VirtualThreadStart and VirtualThreadEnd events, which were implemented in #15254.

The only difference is that the VirtualThreadMount and VirtualThreadUnMount events are part of the JVMTI Extension API. Existing JVMTI extension events are implemented in jvmtiExtensionMechanism.c. Sample JVMTI extension events:

openj9/runtime/jvmti/jvmtiExtensionMechanism.c

Lines 737 to 743 in 3f2deca

	static const J9JVMTIExtensionEventInfo J9JVMTIExtensionEventInfoTable[] = {
	{
	J9JVMTI_EVENT_COM_IBM_COMPILING_START,
	COM_IBM_COMPILING_START,
	J9NLS_JVMTI_COM_IBM_COMPILING_START_DESCRIPTION,
	SIZE_AND_TABLE(jvmtiCompilingStart_params),
	},

fyi @fengxue-IS @tajila

[babsingh]

Reopening since the disabled tests still need to be re-enabled.

[babsingh]

The JVMTI VirtualThread[Mount|UnMount] events were implemented in #16501.

For JDK20, no test is disabled due to this issue in https://github.com/adoptium/aqa-tests/blob/master/openjdk/excludes/ProblemList_openjdk20-openj9.txt.

Thus, closing this issue.