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

[Jini George]

Thanks a bunch, JC ! Could have a Reviewer also take a look at this 
please ?

- Jini.

On 11/21/2018 11:05 PM, JC Beyler wrote:
> Hi Jini,
> 
> Looks good to me, thanks for fixing the nits :)
> 
> Thanks,
> Jc
> 
> 
> On Wed, Nov 21, 2018 at 9:29 AM Jini George <jini.george at oracle.com 
> <mailto:jini.george at oracle.com>> wrote:
> 
>     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>
>      >> <mailto:gary.adams at oracle.com <mailto:gary.adams at oracle.com>>
>     <gary.adams at oracle.com <mailto:gary.adams at oracle.com>
>      >> <mailto: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
> 
> 
> 
> -- 
> 
> Thanks,
> Jc