RFR(XXS): 8145312: [TESTBUG] CMS: unable to create: There is insufficient memory

Dmitry Dmitriev dmitry.dmitriev at oracle.com
Wed Feb 17 18:06:32 UTC 2016


Hello Jon,

Thank you for the review&suggestion! Please, see my comment inline.

On 17.02.2016 20:47, Jon Masamitsu wrote:
> Dmitry,
>
> Change looks good.
>
> The minimum size of CMSSamplingGrain should be the minimum object
> size (in bytes) instead of 1.   Would that allow the test to pass?
I think yes, test will not hit OOM for bigger minimum value. As Joseph 
wrote in the bug comment: "
Is this a valid argument: -XX:CMSSamplingGrain=1? Default is 16K and it 
succeeds.
If I use 1K it doesn't fail.

In fact it doesn't fail with the value 2.

eden_chunk_capacity = (young_gen->max_capacity() + CMSSamplingGrain) / 
CMSSamplingGrain;
     eden_chunk_array = NEW_C_HEAP_ARRAY(HeapWord*, eden_chunk_capacity, 
mtGC);

with 2, there's just enough c heap. "

Probably, we can consider changing of the minimum value for this flag?

Thank you,
Dmitry

>
> Jon
>
>
> On 2/12/2016 12:04 PM, Dmitry Dmitriev wrote:
>> Hello,
>>
>> Please, review small fix to the TestOptionsWithRanges test to exclude 
>> testing of min value for CMSSamplingGrain option, because this can 
>> cause OOM error.
>>
>> JBS: https://bugs.openjdk.java.net/browse/JDK-8145312
>> webrev.00: http://cr.openjdk.java.net/~ddmitriev/8145312/webrev.00/ 
>> <http://cr.openjdk.java.net/%7Eddmitriev/8145312/webrev.00/>
>>
>> Thanks,
>> Dmitry
>



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