RFR: 8276658: Clean up JNI local handles code

[Coleen Phillimore]

On Thu, 11 Nov 2021 06:35:59 GMT, David Holmes <dholmes at openjdk.org> wrote:

>> JNI Local handles can only be created by JavaThread (there's an assert in make_local) but the fields are added to Thread.
>> Move the fields to JavaThread and adding JavaThread* argument.
>> Also, the global freelist isn't very useful now that global JNI handles don't use JNIHandleBlock, so the locking that claims incorrectly to block for safepoint is removed.
>> Lastly, there's at least 3 places that duplicate pushing a new JNIHandleBlock to the thread for temporarily adding JNI local handles. These have been moved to common code with a JNIHandleMark object, moved from jvmci code.
>> The commits are separate to help reviewing, but the entire change has been tested together with tier1-6.
>> The commits in this change have been performance tested individually and together with no meaningful differences from mainline.
>
> src/hotspot/share/runtime/vmThread.hpp line 63:
> 
>> 61: class VMThread: public NamedThread {
>> 62:  private:
>> 63:   volatile bool _is_running;
> 
> I don't see this being initialized to false.

Good catch!

-------------

PR: https://git.openjdk.java.net/jdk/pull/6336