RFR: 8274191: Improve g1 evacuation failure injector performance [v2]

[Thomas Schatzl]

> Hi all,
> 
>   can I have reviews for this change that improves evacuation failure injector performance to be usable for pinned region performance work?
> 
> The suspected reason I think why performance is so bad (image in the CR), is that the unsynchronized reads and writes to `G1YoungGCEvacFailureInjector::_evacuation_failure_object_count` cause massive performance issue if done millions of times.
> 
> This change makes that counter thread-local, fixing that issue completely.
> 
> I initially had a prototype using a `THREAD_LOCAL`, but when testing I had the feeling that this is/was slightly slower and I thought that adding a variable to every thread where most do not use them seems to be a waste.
> 
> Testing: local testing, GHA
> 
> Thanks,
>   Thomas

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

  kbarrett review

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/5650/files
  - new: https://git.openjdk.java.net/jdk/pull/5650/files/f2f9c651..7925c987

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=5650&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=5650&range=00-01

  Stats: 6 lines in 2 files changed: 0 ins; 5 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5650.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5650/head:pull/5650

PR: https://git.openjdk.java.net/jdk/pull/5650