RFR: 8238761: Asynchronous handshakes [v3]

[Coleen Phillimore]

On Mon, 21 Sep 2020 11:02:10 GMT, Robbin Ehn <rehn at openjdk.org> wrote:

>> src/hotspot/share/runtime/handshake.cpp line 313:
>> 
>>> 311:   }
>>> 312:
>>> 313:   int executed_by_driver = 0;
>> 
>> Again why driver?? Isn't it either the current thread or the target that will execute the op?
>
> The thread executing this handshake operation, what the current thread is doesn't matter.
> You can't use current threads resources or be dependent otherwise on it.
> 
> Exception being locking issues in JVM TI, where we are dependent that requester have locked JVM TI state lock for us,
> but we are not dependent that the current thread is the owner. So checking that the lock is held by requester doesn't
> matter for how is the 'driver'.

The "driver" concept is odd.  Should it really be caller?  Like the thread that called VMHandshake?

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PR: https://git.openjdk.java.net/jdk/pull/151