On Wed, 23 Nov 2022 10:14:23 GMT, Serguei Spitsyn <sspit...@openjdk.org> wrote:
>> This problem has two sides. >> One is that the `VirtualThread::run() `cashes the field `notifyJvmtiEvents` >> value. >> It caused the native method `notifyJvmtiUnmountBegin()` not called after the >> field `notifyJvmtiEvents` >> value has been set to `true` when an agent library is loaded into running VM. >> The fix is to get rid of this cashing. >> Another is that enabling `notifyJvmtiEvents` notifications needs a >> synchronization. >> Otherwise, a VTMS transition start can be missed which will cause some >> asserts to fire. >> The fix is to use a JvmtiVTMSTransitionDisabler helper for sync. >> >> Testing: >> The originally failed tests are passed now: >> >> runtime/vthread/RedefineClass.java >> runtime/vthread/TestObjectAllocationSampleEvent.java >> >> In progress: >> Run the tiers 1-6 to make sure there are no regression. > > Serguei Spitsyn has updated the pull request incrementally with one > additional commit since the last revision: > > remove caching if notifyJvmtiEvents in yieldContinuation Would it be possible to summarize behavior for when an agent enables the capability as a virtual thread executes for the first time or it continues after yield? More specifically JVMTI will be notified of a mount end without a correspond mount begin. It might be that we can narrow this down to if finish_VTMS_transition is okay without a preceding start_VTMS_transition. ------------- PR: https://git.openjdk.org/jdk/pull/11304
