RFR: 8170737: Not enough old space utilisation

Dmitry Fazunenko dmitry.fazunenko at oracle.com
Fri Jan 13 16:55:11 UTC 2017


Hi Michail,

GarbageProducer tries to predict at the beginning how many objects to 
allocate later to achieve target memory usage percent.
This way doesn't look like a good idea:
- objects created by libraries (during initialization) may not be 
collected yet
- eatMetaspace() besides allocating metaspace consumes some heap space, 
but this amount is not taken into account.

Will it make sense to use MXBean for heap as well as for metaspace?

Thanks,
Dima

ps: one more nit: "GarbageProducer{" - please insert a space.

On 13.01.2017 14:56, Michail Chernov wrote:
> Hi,
>
> Could I have a reviews for this change, please?
>
> http://cr.openjdk.java.net/~mchernov/8170737/webrev.00/
> https://bugs.openjdk.java.net/browse/JDK-8170737
>
> Test fails because Runtime.maxMemory() results depends on the heap 
> size shrinking. So need to calculate the expected heap occupation 
> before a garbage allocation. Tests were updated accordingly. Also 
> GcProvokerImpl.java was removed because it was not removed on previous 
> commit by mistake.
> Tested via RBT.
>
> Thanks,
> Michail




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