RFR: 8031686: G1: assert(_hrs.max_length() == _expansion_regions) failed (original) (raw)

Jon Masamitsu jon.masamitsu at oracle.com
Thu Jan 16 18:00:00 UTC 2014

Looks good.

On 01/16/2014 05:43 AM, Stefan Johansson wrote:

Hi,

Please review this small fix for: https://bugs.openjdk.java.net/browse/JDK-8031686 Webrev: http://cr.openjdk.java.net/~sjohanss/8031686/webrev.00/ Summary: The failing assertion is caused by an erroneous calculation done when setting up the regions array in HeapRegionSeq. When using a large heap a pointer calculation will overflow (since ptrdifft is signed) and this will in turn lead to the regions array being created longer that it should be. For non debug builds this will lead to increased memory usage and jmap will report a faulty value for the number of regions. The fix is to use the pointerdelta-function to do the calculation. Note: The bug is currently targeted for 8 but is defer-requested and should be moved to 9 shortly. I plan to fix it in 9 and backport it to 8u20. Testing: * Manually verified that we are able to start 32-bit VMs with more than 2g of heap using a debug build. Thanks, Stefan

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