RFR: 8336707: Contention of ForkJoinPool grows when stealing works [v28]

[Doug Lea]

> This addresses tendencies in previous update to increase fencing, scanning, and signalling that can increase contention, and slow down performance especially on ARM platforms. It also uses more ARM-friendly constructions to reduce overhead (leading to several changes that all of the same form),

Doug Lea has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 49 additional commits since the last revision:

 - Merge branch 'openjdk:master' into JDK-8336707
 - Merge branch 'openjdk:master' into JDK-8336707
 - Rename variable
 - Merge branch 'openjdk:master' into JDK-8336707
 - Improve readbility; tweak runState checks
 - Address review comments
 - Merge remote-tracking branch 'refs/remotes/origin/JDK-8336707' into JDK-8336707
 - Merge branch 'openjdk:master' into JDK-8336707
 - Merge branch 'openjdk:master' into JDK-8336707
 - Reconcile internal docs; renamings
 - ... and 39 more: https://git.openjdk.org/jdk/compare/b2cc1d00...a32e818d

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Changes:
  - all: https://git.openjdk.org/jdk/pull/21507/files
  - new: https://git.openjdk.org/jdk/pull/21507/files/cb179dda..a32e818d

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=21507&range=27
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=21507&range=26-27

  Stats: 21547 lines in 744 files changed: 11045 ins; 7517 del; 2985 mod
  Patch: https://git.openjdk.org/jdk/pull/21507.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21507/head:pull/21507

PR: https://git.openjdk.org/jdk/pull/21507