RFR: 8041946 - CMM Testing: 8u40 an allocated humongous object at the end of the heap should not prevents shrinking the heap

Andrey Zakharov andrey.x.zakharov at oracle.com
Wed Jun 11 15:39:16 UTC 2014

Hi, Jesper. Thanks for point.
Here is updated webrev:


Tested locally as very minor changes


On 11.06.2014 17:19, Jesper Wilhelmsson wrote:
> Hi Andrey,
> As it is used, the constant MINIMAL_HEAP_SIZE does not define the 
> minimal heap size but the minimal young gen size. Would you consider 
> calling it MINIMAL_YOUNG_SIZE instead?
> Besides that it looks ok.
> /Jesper
> Andrey Zakharov skrev 9/6/14 16:31:
>> Hi, everyone!
>> Please, review this test for new feature in G1 - sorted free list 
>> which make
>> possible shrinking of the defragmented heap.
>> To proper testing of free list sorting we need to defragment memory 
>> with small
>> young and humongous objects.
>> This is test scenario:
>>   - make enough space for new objects to prevent it going old.
>>   - allocate bunch of small objects, and a bit of humongous several 
>> times
>> (ssssHssssHssssHssssHssssHssssHssssHssssH)
>>   - free almost all of allocated stuff. Check that heap shrinks after 
>> GC.
>> (-----------H)
>> Webrev: 
>> http://cr.openjdk.java.net/~fzhinkin/azakharov/8041946/webrev.00/
>> Bug: https://bugs.openjdk.java.net/browse/JDK-8041946
>> I have tested it along all major platforms and it works fine. There 
>> is lag on
>> Solaris MXBeans about memory usage, so I need sleep by 1s.
>> It will be very nicely if somebody advice me about method which 
>> "flush" memory
>> usage info to remove this sleep.
>> Thanks.

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