G1 native memory consumption

[Thomas Schatzl]

Hi Milan,

On Sun, 2017-03-12 at 00:38 +0000, Milan Mimica wrote:
> Hi again
> 
> I have tried -XX:G1RSetSparseRegionEntries=64 and it did reduce
> native memory usage:
> -                  Internal (reserved=1203MB, committed=1203MB)
>                             (malloc=1203MB #329024)
> vs.
> 
> -                  Internal (reserved=2155MB, committed=2155MB)
>                             (malloc=2155MB #567485)
> 
> There is no measurable performance impact.

Great to hear, and also somewhat expected :)

Did you check the memory increase for the mtGC category does not use up all the savings in the mtInternal category?

> I have a question: why is BitMap PerRegionTable::_bm allocated using
> mtInternal memory qualifier? Wouldn't mtGC be a better fit?

I filed JDK-8176571.

Thanks,
  Thomas