RFR: 8283368: G1: Remove G1SegmentedArraySegment MEMFLAGS template parameter [v2]

[Ivan Walulya]

> Hi all,
> 
> Please review this change to remove the MEMFLAGS template parameter for G1SegmentedArraySegment and make it a runtime configuration parameter. This reduces on the code bloat due to templating because many of the methods in G1SegmentedArraySegment are independent of the template parameter.
> 
> To achieve this we added factory methods for handling allocation and deallocation. Having the factory methods allows us to embed the array data with the G1SegmentedArraySegment struct thus limiting the allocation to a single allocation as well as the deallocation. One upside to this approach is that we limit the allocation and deallocation overheads. 
> 
> Thanks
> Ivan

Ivan Walulya has updated the pull request incrementally with one additional commit since the last revision:

  Albert review

-------------

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/7891/files
  - new: https://git.openjdk.java.net/jdk/pull/7891/files/ea77e81b..c1f80a9f

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=7891&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=7891&range=00-01

  Stats: 2 lines in 2 files changed: 0 ins; 1 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7891.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7891/head:pull/7891

PR: https://git.openjdk.java.net/jdk/pull/7891