[jdk21u-dev] RFR: 8318986: Improve GenericWaitBarrier performance [v2]

[Aleksey Shipilev]

> Clean backport to drastically improve safepoint performance under heavy load, fixing regression between JDK 11 and JDK 17.
> 
> Additional testing:
>  - [x] Ad-hoc performance runs, expected improvements
>  - [x] MacOS AArch64 server fastdebug, `tier{1,2,3}`

Aleksey Shipilev 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 one additional commit since the last revision:

  Backport 30462f9da40d3a7ec18fcf46e2154fabb5fd4753

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

Changes:
  - all: https://git.openjdk.org/jdk21u-dev/pull/70/files
  - new: https://git.openjdk.org/jdk21u-dev/pull/70/files/3e336a13..98149cc1

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=70&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=70&range=00-01

  Stats: 6357 lines in 286 files changed: 4808 ins; 652 del; 897 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/70.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/70/head:pull/70

PR: https://git.openjdk.org/jdk21u-dev/pull/70