RFR (S) 8251336: Shenandoah: assert "only get here when SATB active" after JDK-8244997

[Coleen Phillimore]

On 8/11/20 1:48 PM, Kim Barrett wrote:
>> On Aug 11, 2020, at 10:41 AM, Coleen Phillimore <coleen.phillimore at oracle.com> wrote:
>>
>>
>> Kim's suggestion for this change looks really good.  I'm re-testing this now:
>>
>> open webrev at http://cr.openjdk.java.net/~coleenp/2020/8251336.02/webrev
>> bug link https://bugs.openjdk.java.net/browse/JDK-8251336
> In release_oop_handles, because Service_lock is a "special" lock and
> touched in lots of places, I'd prefer the deletion not happen under
> the lock.  (I realize this uglifies the code a little bit.)

Because there was no performance reason to use lock free code for this, 
I add to and clean out the linked list under the Service_lock.  I chose 
a simple implementation because there was no performance or correctness 
issue to do otherwise.

I'd rather not change this to be ugly unless it's proven to not be 
correct or performant.

thanks,
Coleen

>
> Other than that, this looks good.
>