RFR: 8017588: SA: jstack -l throws UnalignedAddressException while attaching to core file for java that was started with CMS GC

[David Holmes]

Hi Erik,

One minor nit - can you fix the spelling of anonymous in the agent code:

MISC_IS_ANOYMOUS

Thanks.

Reviewed.

David

On 5/07/2013 7:09 PM, Erik Helin wrote:
> Hi Coleen,
>
> thanks for reviewing!
>
> On 2013-07-03, Coleen Phillimore wrote:
>>
>> Eric,
>>
>> I like the cleanup of instanceKlass.cpp a lot.
>>
>> In the serviceability agent,  does getHeap().getOopSize() return 32
>> for compressed oops?   The vtables and itables are Method*, ie
>> metadata.   Is there a better size for these?
>
> This change is for hotspot 24, so we have a methodOop in vtableEntry :)
>
> So, ObjectHeap.getOopSize() will return oopSize in globalDefinitions.hpp
> which is sizeof(char*). VM.getAddressSize in SA is dependent on
> platform, for x86-64 it will return
> MachineDescriptionAMD64.getAddressSize(), which is defined as 8.
>
> Therefore, it does not matter if the code in
> InstanceKlass.getObjectSize() uses ObjectHeap.getOopSize() or
> VM.getAddressSize(), the result will be the same.
>
> In order to keep the SA code and the hotspot code as similar as
> possible, I think it is better to use ObjectHeap.getOopSize(), since the
> hotspot code does sizeof(klassOop).
>
> Please see a new webrev at:
> http://cr.openjdk.java.net/~ehelin/8017588/webrev.01/
>
> I've also done some further testing on, the following testlists were
> successfully run:
> - vm.quick.testlist
> - vm.tmtools.testlist
> - nsk.sajdi.testlist
>
> in addition to the previous testing:
> - JPRT
> - Running jstack -l -F successfully on a java process using -XX:+UseConcMarkSweepGC
>
> Thanks,
> Erik
>
>> Another set of tests that I think we run with vm.quick.testlist is
>> the nsk.sajdi.testlist and the vm.tmtools.testlist in ute.
>>
>> Thanks,
>> Coleen
>>
>> On 7/3/2013 4:33 AM, Erik Helin wrote:
>>> Hi all,
>>>
>>> this change fixes an issue where we could not run jstack -l -F on a
>>> java process running with -XX:+UseConcMarkSweepGC.
>>>
>>> The problem originated from the following change in hotspot:
>>>   changeset:   3707:8bafad97cd26
>>>   parent:      3693:973046802b6f
>>>   7158552: The instanceKlsss::_host_klass is only needed for anonymous class for JSR 292 support.
>>>
>>>   diff --git a/src/share/vm/oops/instanceKlass.hpp b/src/share/vm/oops/instanceKlass.hpp
>>>   --- a/src/share/vm/oops/instanceKlass.hpp
>>>   +++ b/src/share/vm/oops/instanceKlass.hpp
>>>   @@ -717,9 +763,11 @@
>>>      {
>>>        return object_size(align_object_offset(vtable_length()) +
>>>                           align_object_offset(itable_length()) +
>>>   -                       (is_interface() ?
>>>   -                        (align_object_offset(nonstatic_oop_map_size()) + (int)sizeof(klassOop)/HeapWordSize) :
>>>   -                        nonstatic_oop_map_size()));
>>>   +                       ((is_interface() || is_anonymous()) ?
>>>   +                         align_object_offset(nonstatic_oop_map_size()) :
>>>   +                         nonstatic_oop_map_size()) +
>>>   +                       (is_interface() ? (int)sizeof(klassOop)/HeapWordSize : 0) +
>>>   +                       (is_anonymous() ? (int)sizeof(klassOop)/HeapWordSize : 0));
>>>      }
>>>
>>> The corresponding code in the serviceability agent was not updated:
>>>
>>>   agent/src/share/classes/sun/jvm/hotspot/oops/InstanceKlass.java:
>>>    public long getObjectSize() {
>>>    long bodySize =    alignObjectOffset(getVtableLen() * getHeap().getOopSize())
>>>                     + alignObjectOffset(getItableLen() * getHeap().getOopSize())
>>>                     + (getNonstaticOopMapSize()) * getHeap().getOopSize();
>>>    return alignObjectSize(headerSize + bodySize);
>>>    }
>>>
>>> This fix updates the SA code to be like the hotspot code. I've also
>>> introduced variables in the hotspot code and in the SA code to make it
>>> easier to compare the two versions.
>>>
>>> Webrev: http://cr.openjdk.java.net/~ehelin/8017588/webrev.00/
>>>
>>> Testing:
>>> - JPRT
>>> - Running jstack -l -F successfully on a java process using -XX:+UseConcMarkSweepGC
>>>
>>> Thanks,
>>> Erik
>>