[jdk16] RFR: 8259032: MappedMemorySegmentImpl#makeMappedSegment() ignores Unmapper#pagePosition [v2]

[Maurizio Cimadamore]

> Hi,
> this patch fixes an oversight where the address() method in FileChannelImpl.Unmapper does not take into account the value of `pagePosition` - this leads to a situation in which, effectively, the specified offset when mapping the segment is ignored by the runtime (because base address will always be aligned to some known quantity - which is OS/platform dependent).
> 
> To test this I had to break open into FileChannelImpl and ready the granularity.

Maurizio Cimadamore has updated the pull request incrementally with one additional commit since the last revision:

  Simplify test not to depend on implementation internals

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

Changes:
  - all: https://git.openjdk.java.net/jdk16/pull/84/files
  - new: https://git.openjdk.java.net/jdk16/pull/84/files/b58a381c..7a78d724

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk16&pr=84&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk16&pr=84&range=00-01

  Stats: 25 lines in 1 file changed: 7 ins; 14 del; 4 mod
  Patch: https://git.openjdk.java.net/jdk16/pull/84.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk16 pull/84/head:pull/84

PR: https://git.openjdk.java.net/jdk16/pull/84