RFR: 8221102: Allow GC threads to participate in threads claiming protocol

[Kim Barrett]

> On Apr 1, 2019, at 5:43 AM, Roman Kennke <rkennke at redhat.com> wrote:
> 
> Hi Kim,
> 
>>>>> Also, the resetting logic warrants a test, it is so rare, it will otherwise not get executed, but if it fails, it would be catastrophic.
>>>> I was hoping the resetting code was simple enough to not require a
>>>> test.  I will see if I can come up with a sensible gtest.
>>> 
>>> I guess the 'design' of the claiming protocol is just making almost everything not-obvious. I think for this reason alone I shall go ahead and work on limiting/eliminating its usage outside of thread.cpp anyway.
>> Another function similar to possibly_parallel_threads_do that operated
>> on all threads seems like it would be a good thing to have.  Possibly
>> stealing the existing name and renaming the old operation.  I'd like
>> the defer that to a followup RFE rather than as part of this bug fix.
> 
> Yes, let's do that.

https://bugs.openjdk.java.net/browse/JDK-8221785

>>> If it's too hard to come up with a gtest, then go ahead with your proposed change.
>> It turned out not to be *too* difficult to add a gtest.  New webrevs:
>> full: http://cr.openjdk.java.net/~kbarrett/8221102/open.01/
>> incr: http://cr.openjdk.java.net/~kbarrett/8221102/open.01.inc/
> 
> Great! Patch looks good to me!
> 
> Thanks,
> Roman


Thanks.