RFR (XS) 8251949: ZGC: Set explicit heap size for compiler/gcbarriers tests

[Stuart Monteith]

On 18/08/2020 13:41, Aleksey Shipilev wrote:
> Testbug:
>    https://bugs.openjdk.java.net/browse/JDK-8251949
> 
> On large TR 3970X, jtreg asks for MaxRAMFraction=0, which makes ZGC use 128M heap for some tests. These tests reliably 
> fail with OOM in jdk-updates/jdk11u-dev:
>    compiler/gcbarriers/UnsafeIntrinsicsTest.java
>    compiler/loopopts/TestRangeCheckPredicatesControl.java
> 
> While they do not fail in jdk/jdk, I think it makes more sense to add explicit heap sizes in jdk/jdk, and then backport 
> to 11u. The alternative is to backport ZGC improvements that make it more resilient at small heap sizes (like 
> JDK-8234338?); but I am not feeling very comfortable doing and testing that.
> 
> Webrev:
>    https://cr.openjdk.java.net/~shade/8251949/webrev.01/
> 
> Testing: affected tests in jdk/jdk and jdk-updates/jdk11u-dev
> 

Hi Aleksey,

    That looks ok to me, tests fine on jdk/jdk on aarch64.