Strage jmap heap output for G1 on 32bit JVM

Jakub Kubryński jk at codearte.io
Wed May 20 14:50:32 UTC 2015


Yes,  I'll check it on latest Jdk9 and let you know.

Best,
Jakub
20 maj 2015 16:35 "Jesper Wilhelmsson" <jesper.wilhelmsson at oracle.com>
napisał(a):

> Ok. I tried that as well but it didn't reproduce.
>
> After a closer look it seems as if it is the number of regions that is
> wrong and causes the huge free size reported. There have been a few changes
> in this area recently which may have fixed this issue.
>
> Is it possible to try your reproducer with a recent build of JDK 9 or the
> latest version of 8u from the OpenJDK source repositories?
> /Jesper
>
>
> Jakub Kubryński skrev den 20/5/15 15:23:
>
>> 64 bit Linux with 32bit JVM.
>>
>> Cheers,
>> Jakub
>>
>> 20 maj 2015 15:18 "Jesper Wilhelmsson" <jesper.wilhelmsson at oracle.com
>> <mailto:jesper.wilhelmsson at oracle.com>> napisał(a):
>>
>>     Hi,
>>
>>     Does this reproduce every time?
>>     What platform is it?
>>
>>     I have tried to reproduce this on 32bit linux but can't see anything
>> weird
>>     there. It seems likely that there is a variable with the wrong type
>>     somewhere on the way. I'll see if I can find something.
>>     /Jesper
>>
>>
>>     Jakub Kubryński skrev den 15/5/15 17:22:
>>
>>         Hi,
>>
>>         I've just checked that on 32bit JVM (HotSpot 8u45) jmap reports
>> strange
>>         region
>>         information for G1 collector. As you can see Xmx is set to 2G
>> (which fits
>>         MaxHeapSize) but regions count (almost 15k) and capacity is
>> incorrect.
>>         Any ideas
>>         why?
>>
>>         Heap Configuration:
>>              MinHeapFreeRatio         = 40
>>              MaxHeapFreeRatio         = 70
>>              MaxHeapSize              = 2147483648 <tel:2147483648>
>> (2048.0MB)
>>              NewSize                  = 1048576 (1.0MB)
>>              MaxNewSize               = 428867584 (409.0MB)
>>              OldSize                  = 4194304 (4.0MB)
>>              NewRatio                 = 2
>>              SurvivorRatio            = 8
>>              MetaspaceSize            = 16777216 (16.0MB)
>>              CompressedClassSpaceSize = 1073741824 (1024.0MB)
>>              MaxMetaspaceSize         = 4294963200 (4095.99609375MB)
>>              G1HeapRegionSize         = 1048576 (1.0MB)
>>
>>         Heap Usage:
>>         G1 Heap:
>>              regions  = 14336
>>              capacity = 15032385536 <tel:15032385536> (14336.0MB)
>>              used     = 76347888 (72.81101989746094MB)
>>              free     = 14956037648 (14263.188980102539MB)
>>              0.5078893687043872% used
>>
>>         --
>>         Best regards,
>>         Jakub Kubrynski
>>
>>
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