RFR: 8226797: serviceability/tmtools/jstat/GcCapacityTest.java fails with Exception: java.lang.RuntimeException: OGCMN > OGCMX (min generation capacity > max generation capacity)

[Stefan Karlsson]

Thanks, StefanJ.

StefanK

On 2019-12-12 13:27, Stefan Johansson wrote:
> Hi Stefan,
> 
> On 2019-12-12 13:05, Thomas Schatzl wrote:
>> Hi,
>>
>> On 12.12.19 13:01, Stefan Karlsson wrote:
>>> Hi all,
>>>
>>> Please review this patch to fix a problem with unintialized values in 
>>> our generation counters.
>>>
>>> https://cr.openjdk.java.net/~stefank/8226797/webrev.01/
>>> https://bugs.openjdk.java.net/browse/JDK-8226797
>>>
>>> The jstat values NGCMN and OGCMN both return uninitialized values.
>>>
>>> I stumbled upon this while creating a patch to remove the 
>>> GenerationSpec class.
>>>
>>> GenerationSpec::_min_size is never initialized, and then used to 
>>> create the generations:
>>>
>>>      case Generation::DefNew:
>>>        return new DefNewGeneration(rs, _init_size, _min_size, 
>>> _max_size);
>>>
>>>      case Generation::MarkSweepCompact:
>>>        return new TenuredGeneration(rs, _init_size, _min_size, 
>>> _max_size, remset);
>>>
>>> That in turn uses it to initialize the perf counters:
>>> DefNewGeneration::DefNewGeneration(ReservedSpace rs,
>>>                                     size_t initial_size,
>>>                                     size_t min_size,
>>>                                     size_t max_size,
>>>                                     const char* policy)
>>> ...
>>>    _gen_counters = new GenerationCounters("new", 0, 3,
>>>        min_size, max_size, &_virtual_space);
>>>
>>> I'm setting the value to _init_size, because it reflects how 
>>> MinNewSize and MinOldSize relates to NewSize and OldSize.
>>
>> Great find!
>>
>> Looks good.
> Looks good to me too,
> StefanJ
> 
>>
>>   Thomas