RFR (XS): JDK-8061449: G1: FreeRegionList_test() fails with G1 after the JDK-8058534 fix to HeapRegion::orig_end()

[Bengt Rutisson]

Hi all,

Can I have a couple for reviews of a fix for this internal VM test?

http://cr.openjdk.java.net/~brutisso/8061449/webrev.00/

Bug link:
https://bugs.openjdk.java.net/browse/JDK-8061449

Background:

When this fix was pushed:

Remove HeapRegion::_orig_end
https://bugs.openjdk.java.net/browse/JDK-8058534

The heap region constructor actually examines the MemRegion that is 
passed to it. In the internal VM tests there was a test, 
FreeRegionList_test(), that passed a random MemRegion to the heap region 
constructor. This worked before, but now stopped working. The original 
fix, JDK-8058534, is correct so the fix for the failing test is to set 
up proper memory regions and pass those to the heap region constructors.

Before my suggested patch this fails:

$ java -XX:+ExecuteInternalVMTests -XX:+UseG1GC -version

The test fails on this assert in HeapRegion::hr_clear():

assert(_end == orig_end(),

With my suggested patch all tests pass with the above command line.

Thanks,
Bengt