RFR (XL): 8054818: Refactor HeapRegionSeq to manage heap region and auxiliary data

[Thomas Schatzl]

Hi all,

  can I have reviews for this somewhat large refactoring change? It is
about refactoring the HeapRegionSeq class to manage heap region and
auxiliary data.

I.e. currently HeapRegionSeq only manages the HeapRegion instances
corresponding to the heap's region. The change gives HeapRegionSeq more
responsibilities, encapsulating functionality related to heap memory
management. This decreases the amount of responsibilities (and
complexity) for the G1CollectedHeap class: decisions about how heap
related memory is allocated/freed/iterated (i.e. how the heap regions
are actually allocated in the heap) is removed from G1CollectedHeap.

This change only changes the interface to this functionality. It is a
preparatory change for JDK-8038423 "G1: Decommit memory within the
heap", so the change might be slightly more extensive than really
required.

The RFR for JDK-8038423 will follow to look at it in context.

There is another CR that renames HeapRegionSeq to HeapRegionmanager too.

CR:
https://bugs.openjdk.java.net/browse/JDK-8054818

Webrev:
http://cr.openjdk.java.net/~tschatzl/8054818/webrev/

Testing:
jprt, nightly and bigapps (kitchensink, ...) with -XX:+UseG1GC

Thanks,
  Thomas