RFR (XS): 8055525: Bigapp weblogic+medrec fails to startup after JDK-8038423

[Thomas Schatzl]

Hi all,

  can I have reviews for the following tiny change that fixes startup on
linux with large pages enabled and said large pages configured by the
OS?

The problem is some unnecessary initialization in G1RegionToSpaceMapper
that fakes that all regions are initially committed in that case.

This is not required, because the lower layer (G1PageBasedVirtualSpace)
already does fake commit/uncommit calls (in that case these calls are
nops like done elsewhere).

CR:
https://bugs.openjdk.java.net/browse/JDK-8055525
Webrev:
http://cr.openjdk.java.net/~tschatzl/8055525/webrev/

Testing:
jprt, manual local testing of bigapps/medrec before/after the change

Thanks,
  Thomas