RFR: (S): JDK-8213323: sa/TestJmapCoreMetaspace.java and sa/TestJmapCore.java fail with ZGC

[Jini George]

The modified webrev with the RuntimeException and the nit removed is at:

http://cr.openjdk.java.net/~jgeorge/8213323/webrev.01/

Thanks!
Jini.

On 11/12/2018 12:41 PM, Jini George wrote:
> Thank you very much, JC, for looking into this.
> 
> http://mail.openjdk.java.net/pipermail/zgc-dev/2018-August/000455.html
> 
> The link above provides an explanation of why it is difficult to support 
> ZGC with SA where there is an iteration over the heap. And currently, I 
> am unsure as to whether we will devise a way to overcome this issue. We 
> currently have the following JBS entry for tracking this.
> 
> https://bugs.openjdk.java.net/browse/JDK-8207843 (SA: Add support for 
> Object Histogram with ZGC)
> 
> I have added a comment in the ER above to keep track of enabling the 
> tests if this is resolved.
> 
> I agree with your comment on throwing a RuntimeException. Doing this 
> avoids the misleading "heap written to" message. I will modify this and 
> remove the ';' you pointed out and post another webrev.
> 
> Thank you,
> Jini.
> 
> 
> 
> On 11/9/2018 9:36 PM, JC Beyler wrote:
>> Hi Jini,
>>
>> The webrev looks good to me as well except for a few questions/comments:
>>
>> I have a generic question that is related to the webrev:
>>    - Are there plans at some point for Jmap to support ZGC heaps in 
>> the future ? Or is this infeasible?
>>          I ask because if a lot of tests are disabled for ZGC for a 
>> limited amount of time (in order to provide time for future support) 
>> there should be a means to scrub the tests at a later date to see 
>> which are now supported, no?
>>
>>    - In 
>> http://cr.openjdk.java.net/~jgeorge/8213323/webrev.00/src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/utilities/HeapHprofBinWriter.java.html: 
>>
>>
>>   397         if (vm.getUniverse().heap() instanceof ZCollectedHeap) {
>>   398             System.err.println("WARNING: Operation not supported 
>> for ZGC.");
>>   399             return;
>>   400         };
>>
>>       - 1 nit is the ';'  after the closing '}'
>>       - Should the code throw a RuntimeException instead? Just 
>> printing an error seems "weak" for me when this really won't work. Of 
>> course, that means tracking the callers now of write and probably 
>> adding exception handling there and I'm not sure that is something 
>> that is warranted here but thought I would ask :)
>>
>> Thanks!
>> Jc
>>
>>
>>
>> Thanks,
>> Jc
>>
>> On Fri, Nov 9, 2018 at 1:47 AM gary.adams at oracle.com 
>> <mailto:gary.adams at oracle.com> <gary.adams at oracle.com 
>> <mailto:gary.adams at oracle.com>> wrote:
>>
>>     Looks OK to me.
>>
>>     On 11/9/18 1:40 AM, Jini George wrote:
>>      > Hello!
>>      >
>>      > Requesting reviews for a small change for disabling the testing of
>>      > TestJmapCoreMetaspace.java and TestJmapCore.java with ZGC. The
>>     change
>>      > also includes skipping of creating the heapdump file with jmap if
>>     the
>>      > GC being used is ZGC.
>>      >
>>      > Webrev: http://cr.openjdk.java.net/~jgeorge/8213323/webrev.00/
>>      > Bug ID: https://bugs.openjdk.java.net/browse/JDK-8213323
>>      >
>>      > Thanks,
>>      > Jini.
>>
>>
>>
>>
>> -- 
>>
>> Thanks,
>> Jc