RFR (XS) 8215329: Modify ZGC requirement for HeapMonitorThreadTest.java

[Per Liden]

Hi again,

I ran this test some more and managed to get an OOME even with a 768M 
heap. I'm getting a bit suspicious that something else is wrong here. 
Let me dig into this some more and see if I can understand what the real 
issue is.

cheers,
Per

On 12/13/2018 10:31 AM, Per Liden wrote:
> Hi JC,
> 
> What's the reason to exclude ZGC from this test to begin with? From what 
> I can tell, it's because the test is using a slightly too small heap, or 
> are there some other reason? I ran it a few times using various heap 
> sizes and the test passes with ZGC when using anything above 612M. So if 
> we instead just dump the heap size a bit, then we get test coverage with 
> ZGC too. I picked 768M here to have some headroom in case the exact 
> limit is run-to-run dependent.
> 
> diff --git 
> a/test/hotspot/jtreg/serviceability/jvmti/HeapMonitor/MyPackage/HeapMonitorThreadTest.java 
> b/test/hotspot/jtreg/serviceability/jvmti/HeapMonitor/MyPackage/HeapMonitorThreadTest.java 
> 
> --- 
> a/test/hotspot/jtreg/serviceability/jvmti/HeapMonitor/MyPackage/HeapMonitorThreadTest.java 
> 
> +++ 
> b/test/hotspot/jtreg/serviceability/jvmti/HeapMonitor/MyPackage/HeapMonitorThreadTest.java 
> 
> @@ -29,8 +29,7 @@
>    * @build Frame HeapMonitor ThreadInformation
>    * @summary Verifies the JVMTI Heap Monitor Thread information sanity.
>    * @compile HeapMonitorThreadTest.java
> - * @run main/othervm/native -Xmx512m -agentlib:HeapMonitorTest 
> MyPackage.HeapMonitorThreadTest
> - * @requires !vm.gc.Z
> + * @run main/othervm/native -Xmx768m -agentlib:HeapMonitorTest 
> MyPackage.HeapMonitorThreadTest
>    */
> 
>   import java.util.List;
> 
> cheers,
> Per
> 
> On 12/13/2018 05:44 AM, JC Beyler wrote:
>> Hi all,
>>
>> When working on another webrev, I saw this problem:
>>
>> Webrev: http://cr.openjdk.java.net/~jcbeyler/8215329/webrev.00/
>> Bug: https://bugs.openjdk.java.net/browse/JDK-8215329
>>
>> (Basically, from what I understood from an email from Per Liden:
>>     - @requires !vm.gc.Z -> ZGC is built in the JDK
>>     - @requires vm.gc != "Z" -> ZGC is being used for the runtime
>> )
>>
>> Thanks,
>> Jc