RFR: 8272985: Reference discovery is confused about atomicity and degree of parallelism [v2]

[Thomas Schatzl]

> Hi all,
> 
>   can I have reviews for this change that fixes some (apparent) confusion between atomicity (of the discovery in the `ReferenceProcessor` sense) vs. the currently selected degree of parallelism?
> 
> For all four different combinations of atomicity and parallelism the `discovered` link in the `java.lang.ref.Reference` needs to be updated differently using a different kind of access, instead of just two based on atomicity.
> 
> I'll fix the use of `atomic` in `ReferenceProcessor` in a separate CR to hopefully remove the confusion for the reader too.
> 
> Testing: tier1-5, internal perf benchmarks without regressions
> 
> Thanks,
>   Thomas

Thomas Schatzl has updated the pull request incrementally with one additional commit since the last revision:

  Some more refactorng

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/5314/files
  - new: https://git.openjdk.java.net/jdk/pull/5314/files/115be125..e213e69c

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=5314&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=5314&range=00-01

  Stats: 4 lines in 1 file changed: 0 ins; 0 del; 4 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5314.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5314/head:pull/5314

PR: https://git.openjdk.java.net/jdk/pull/5314