RFR: 8210986: Add OopStorage cleanup to ServiceThread

[Kim Barrett]

> On Nov 5, 2018, at 4:56 AM, Robbin Ehn <robbin.ehn at oracle.com> wrote:
> 
> Hi Kim,
> 
> Seems reasonable, I must admit I hate the MutexUnlocker, but I see way you choose to that pattern here.

Thanks.

As you might guess, without MutexUnlocker the code structure becomes more complicated.

> It's not obvious to me why you needed to change the:
> 644   OrderAccess::storeload();
> to
> 668   OrderAccess::fence();

I’m finding it a little bit less difficult to reason about code that consistently
uses acquire/release/fence, without the other ordering forms.