RFR: 8306028: separate ThreadStart/ThreadEnd events posting code in JVMTI VTMS transitions [v8]

[Doug Simon]

On Tue, 2 May 2023 02:01:44 GMT, Serguei Spitsyn <sspitsyn at openjdk.org> wrote:

>> This refactoring to separate ThreadStart/ThreadEnd events posting code in the JVMTI VTMS transitions is needed for future work on JVMTI scalability and performance improvements. It is to easier put this code on slow path.
>> 
>> Testing: mach5 tiers 1-6 were successful.
>
> Serguei Spitsyn has updated the pull request incrementally with one additional commit since the last revision:
> 
>   update copyright comments

src/hotspot/share/runtime/sharedRuntime.cpp line 641:

> 639: JRT_ENTRY(void, SharedRuntime::notify_jvmti_vthread_start(oopDesc* vt, jboolean hide, JavaThread* current))
> 640:   assert(hide == JNI_FALSE, "must be VTMS transition finish");
> 641:   jobject vthread = JNIHandles::make_local(const_cast<oopDesc*>(vt));

Since the current thread is in the `current` arg, it could be used here when creating the local handle.

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PR Review Comment: https://git.openjdk.org/jdk/pull/13484#discussion_r1223444559