RFR: 8224815: Remove non-GC uses of CollectedHeap::is_in_reserved()

[Stefan Karlsson]

Hi Erik,

On 2019-08-09 09:43, Erik Österlund wrote:
> Hi,
> 
> The CollectedHeap::is_in_reserved() function assumes the GC has a 
> contiguous heap. This might not be the case, and hence the shared code 
> should not make assumptions about that. It should use 
> CollectedHeap::is_in() instead.
> 
> However, CompressedOops inherently assumes the heap is contiguous, so I 
> let it know about the reserved region.
> 
> This patch depends on 8229278 and 8229189, which are both out for review 
> right now.
> 
> Bug:
> https://bugs.openjdk.java.net/browse/JDK-8224815
> 
> Webrev:
> http://cr.openjdk.java.net/~eosterlund/8224815/webrev.00/


I think this looks good, but have a few cleanups that I'd like to suggest:

http://cr.openjdk.java.net/~stefank/8224815/webrev.01.review.00/

1) Changed some parameters to accept void* to get rid of some casts

2) Replaced address with HeapWord* in GC code.

3) Moved the code that was moved to initialize_reserved_region and moved 
it into Universe::reserve_heap. I could therefore restore the location 
of the initialize_reserved_region calls. Fixed a test that relied on the 
logging order.

4) Moved the heap address range MemRegion out of NarrowPtrStruct into 
CompressedOops

5) Replaced some DEBUG_ONLY with NOT_DEBUG_RETURN.

6) Minor cleanups

I ran this through tier1.

It's a bit annoying that we still have CollectedHeap::_reserved, but I 
understand why you left it for now. However, I see that the 
Serviceability Agent uses that field. Did you think about if that 
affects ZGC support in SA in any way?

Thanks,
StefanK

> 
> Thanks,
> /Erik