RFR: 8298853: JvmtiVTMSTransitionDisabler should support disabling one virtual thread transitions [v5]

[Serguei Spitsyn]

On Wed, 4 Jan 2023 04:33:53 GMT, David Holmes <dholmes at openjdk.org> wrote:

>> Serguei Spitsyn has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   fix race between VTMS_transition_disable_for_one and start_VTMS_transition
>
> src/hotspot/share/classfile/javaClasses.cpp line 1746:
> 
>> 1744: void java_lang_Thread::dec_VTMS_transition_disable_count(oop java_thread) {
>> 1745:   int val = VTMS_transition_disable_count(java_thread);
>> 1746:   assert(JvmtiVTMSTransition_lock->owned_by_self(), "Must be locked");
> 
> Nit: normally a lock-checking assertion would come first in the function, so that it stands out more.

Okay, thanks. Fixed locally.

> src/hotspot/share/prims/jvmtiThreadState.cpp line 384:
> 
>> 382:   JvmtiThreadState* vstate = java_lang_Thread::jvmti_thread_state(vth());
>> 383:   if (vstate != NULL) {
>> 384:     vstate->set_is_in_VTMS_transition(true);
> 
> Is the VTMS transition flag in the `JvmtiThreadState` dead code now?

Yes. All this dead code has been removed now.

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PR: https://git.openjdk.org/jdk/pull/11690