RFR: 8223312: Utilize handshakes instead of is_thread_fully_suspended [v2]

[Robbin Ehn]

On Tue, 20 Oct 2020 19:54:06 GMT, Richard Reingruber <rrich at openjdk.org> wrote:

>> Thanks, I'm exploring what we need to execute the EB inside the handshake.
>> So far I think that really needs to go in a separate PR, since it becomes really unrelated to this.... picking up your change.
>> 
>>> Hi Robbin,
>>> 
>>> for merging master after integration of #119 I'd suggest to resolve the
>>> conflicts by chosing the alternative from this pr and then apply
>>> [reinrich at 6fa91e3](https://github.com/reinrich/jdk/commit/6fa91e344ed5bf6d877e3f5a2d0d1920591fd441)
>>> (is there a more elegant way to propose a patch?)
>>> 
>>> I successfully tested
>>> 
>>> ```
>>> make run-test TEST=test/jdk/com/sun/jdi/EATests.java
>>> ```
>>> 
>>> which also covers PopFrame and ForceEarlyReturn.
>>> 
>>> More tests are running.
>>> 
>>> For night tests of our team it is unfortunately too late.
>>> 
>>> Thanks, Richard.
>
>> Thanks, I'm exploring what we need to execute the EB inside the handshake.
> 
> I want to experiment with object reallocation without referencing a frame. I think a should be possible to reallocate objects given only the corresponding compiled pc. If so, then a handshake/vm operation can fail with the request to reallocate objects at a pc. This can be done concurrently and then the handshake/vm operation can be restarted.

I pushed the merge. (I manage to pick up bad state in first merge, so I did a second merge to get the fixes for that)
Please have a look.

Still running test, but there were some interest in this change-set (it seem to fix an unrelated bug also) so I published it.

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

PR: https://git.openjdk.java.net/jdk/pull/729