Request for Review (s) - 8060463: ParNew: SurvivorAlignmentInBytes greater then YoungPLABSize cause assert(obj != NULL || plab->words_remaining() < word_sz) failed: Else should have been able to allocate

sangheon sangheon.kim at oracle.com
Thu Mar 24 18:04:26 UTC 2016


Hi Jon,

Looks good.
Thanks for fixing this.

Sangheon


On 03/24/2016 10:26 AM, Jon Masamitsu wrote:
>
>
> On 3/24/2016 9:13 AM, sangheon wrote:
>> Hi Jon,
>>
>> On 03/24/2016 09:00 AM, Jon Masamitsu wrote:
>>> Thanks Sangheon, Thomas, and Michail. Latest versions:
>>>
>>> Delta
>>> http://cr.openjdk.java.net/~jmasa/8060463/webrev_delta.00_01/
>> Thank you for fixing these.
>> BTW, could you add a comma in front of 'PLAB size' as well?
> Fixed.
>
>> And as the test is a new one, I think just '2016' seems correct not 
>> '2014, 2016'.
>
> Fixed.
>
> Thanks again.
>
> Jon
>
>> I don't need a new webrev for these.
>>
>> Thanks,
>> Sangheon
>>
>>
>>>
>>> Full
>>> http://cr.openjdk.java.net/~jmasa/8060463/webrev.01/index.html
>>>
>>> Jon
>>>
>>>
>>> On 3/20/2016 8:04 PM, Jon Masamitsu wrote:
>>>> If SurvivorAlignmentInBytes is larger than the size of the promotion
>>>> LAB an allocation aligned to SurvivorAlignmentInBytes  may fail. The
>>>> allocation of the PLAB depends of the size of the object being
>>>> allocated and if the PLAB is successfully allocated the allocation
>>>> of the object should succeeded (and is checked by an assertion).
>>>> For alignments larger than  PLAB, a larger PLAB is sometimes needed
>>>> to allow for the alignment.
>>>>
>>>> The fix does not try to avoid the need for a new PLAB at the
>>>> next promotion by making the PLAB even larger.  The large
>>>> values of SurvivorAlignmentInBytes  are allowed but not
>>>> expected.  I chose not to make the PLAB even larger for a
>>>> situation I don't expect to see in practice.
>>>>
>>>> https://bugs.openjdk.java.net/browse/JDK-8060463
>>>> http://cr.openjdk.java.net/~jmasa/8060463/webrev.00/
>>>>
>>>> Tested with the newly added test which check a range
>>>> of SurvivorAlignmentInBytes values.
>>>>
>>>> Thanks.
>>>>
>>>> Jon
>>>
>>
>



More information about the hotspot-gc-dev mailing list