The default heap region size calculation has been changed to return larger regions by default. The calculation still aims to have 2048 regions, but two aspects have changed:

 - Only the maximum heap size is considered. The old calculation also took the initial heap size into consideration, but this can give unexpected behavior when no heap size is set.
 - The region size is rounded up to the nearest power of 2 instead of down. This will return larger region sizes in cases where the maximum heap size is not a power of 2.

These changes improve startup and runtime performance.