RFR: 8222252 - Java ergonomics limits heap to 128GB with disabled compressed oops

[Bob Vandette]

Is the GC team ok with the new behavior?

Bob.


> On May 23, 2019, at 10:37 AM, Thomas Schatzl <thomas.schatzl at oracle.com> wrote:
> 
> Hi,
> 
> On Wed, 2019-05-15 at 10:52 -0400, Bob Vandette wrote:
>> I’ve updated the webrev based on your comments.
>> 
>> http://cr.openjdk.java.net/~bobv/8222252/webrev.02/
>> 
>> Changes:
>> 
>> 1. MaxRAM is updated if fractional flags cause us to use OS memory
>> size for heap selection.
>> 2. If MaxRAM is specified with the other fractional based flags, we
>> will use MaxRAM as
>>   upper limit instead of OS memory size.
>> 
>> 
>> Here’s a proposed CSR for this behavioral change.
>> 
>> https://bugs.openjdk.java.net/browse/JDK-8223957
> 
> Please provide a jtreg test checking resulting heap sizing in the
> various situations. Not all combinations are interesting of course,
> e.g. I think the *Fraction flags can be ignored in these tests as they
> are obsolete and others.
> 
> The value of os::physical_memory() could be provided by an appropriate
> whitebox method if not already done.
> 
> Thanks,
>  Thomas
> 
>