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

[Per Liden]

Hi,

On 8/18/20 2:41 PM, 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 

If it's only a problem in jdk11u why stick this in jdk/jdk?

/Per

> 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
>