RFR: 8213175 - MaxHeapSize refuses to go over 32178700288 when running in a docker container

[David Holmes]

Hi Bob,

On 13/03/2019 1:04 am, Bob Vandette wrote:
> Please review this fix for correcting the Heap size when MaxRAMPercentage is used.
> 
> BUG:
> 
> https://bugs.openjdk.java.net/browse/JDK-8213175
> 
> WEBREV:
> 
> http://cr.openjdk.java.net/~bobv/8213175/webrev.0/
> 
> SUMMARY:
> 
> This fix changes the ordering of when we try to determine if we can
> enable UseCompressedOops.  It is now done after more of the Heap size
> calculations are completed.
> 
> The only behavioral change should be that UseCompressedOops will now be
> disabled if someone specifies a MaxRAMPercentage that causes the heap size
> to exceed the amount of memory that can be used with compressed oops.
> Prior to this change, the amount of heap was reduced to the compressed oop
> limit.

It isn't at all clear to me that this is the correct fix here. Why not 
assess this as "not an issue" and require the user to disable compressed 
oops?

Such a behaviour change needs to be discussed and needs a CSR request.

David

> Bob.
>