RFR: 8252513: ZGC: Contiguous memory reservation probing is broken for TB heap sizes

[Per Liden]

Looks good!

/Per

On 8/31/20 1:13 PM, Stefan Karlsson wrote:
> Hi all,
> 
> Please review this patch to fix memory reservation probing for large 
> heap size.
> 
> https://cr.openjdk.java.net/~stefank/8252513/webrev.01/
> https://bugs.openjdk.java.net/browse/JDK-8252513
> 
> If the passed in 'size' is equal to ZAddressOffsetMax, both 'end' and 
> 'increment' becomes 0, and the code will loop forever.
> 
> I've changed the code to at least increment with ZGranuleSize. I've also 
> replaced the usage of 'start <= end', with 'start + size <= 
> ZAddressOfsetMax', since it  makes the code easier to reason about, IMHO.
> 
> Thanks,
> StefanK