RFR: 8064909: FragmentMetaspace.java got OutOfMemoryError

Jon Masamitsu jon.masamitsu at oracle.com
Wed Nov 26 23:00:00 UTC 2014


Dima,

If this test fails with an OOME in the future, I would like it to be
obvious that the failure is not that an OOME occurred.   I cannot
tell that from looking at the test.    Can the test be changed so
I don't have to spend time figuring out that the OOME is not
a failure mode  of the test?

Jon


On 11/26/2014 12:51 PM, Dmitry Fazunenko wrote:
> Hi Jon,
>
> The original version of test worked for 80 seconds trying to perform 
> as many iterations as possible. The number of iterations performed 
> depended on how fast is the machine. With each next iteration the size 
> of generated and loaded classes is growing, so on fast enough machines 
> 80 seconds is enough to run out of heap while generating a class.
>
> The fix not only sets the heap, but limits iterations.  300m heap is 
> enough for 200 iterations.
>
> Your approach, with catching OOME(heap) and passing will also work, 
> but it will reduce the test readability (and potentially could bring 
> more problems).
>
> An alternative approach would be to limit metaspace and heap 
> accordingly and load classes until we don't run out metaspace... But 
> this might take awhile.
>
> So, I hope that Michael's fix is good.
>
> Thanks for looking and expressing comments.
> Dima
>
>
>
>
> On 26.11.2014 22:04, Jon Masamitsu wrote:
>> Michail,
>>
>> Your change makes this test pass but it seems like at
>> some future date 300m might not be big enough
>> (for whatever reason).  Could the test be make to
>> caught an OOME, print out a message saying that
>> an OOME doesn't mean the test failed  but that
>> the test needs a larger heap?  Then pass an
>> exception up (maybe some type of Runtime
>> exception - sorry if that is vague but I don't
>> what type of exception would make sense).  That
>> would mean we wouldn't have to spend time
>> diagnosing what the OOME means again.
>>
>> Jon
>>
>> On 11/26/2014 5:36 AM, Michail Chernov wrote:
>>> Hi,
>>>
>>> Please review this simple fix for nightly test failure:
>>>
>>> Webrev:
>>> http://cr.openjdk.java.net/~eistepan/~mchernov/8064909/webrev.00/
>>> Bug:
>>> https://bugs.openjdk.java.net/browse/JDK-8064909
>>>
>>> Problem: test fails because of OOME (not enough heap size).
>>> Solution: heap size were increased.
>>>
>>> Testing:
>>> jtreg
>>>
>>> Thanks,
>>> Michail
>>
>



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