RFR: 8308479: [s390x] Implement alternative fast-locking scheme [v2]

[Amit Kumar]

On Tue, 13 Jun 2023 03:17:05 GMT, Amit Kumar <amitkumar at openjdk.org> wrote:

>> This PR implements new fast-locking scheme for s390x. Additionally few parameters have been renamed to be in sync with PPC.
>> 
>> Testing done (for release, fastdebug and slowdebug build):
>> All `test/jdk/java/util/concurrent` test with parameters:
>> * LockingMode=2 
>> * LockingMode=2 with -Xint
>> * LockingMode=2 with -XX:TieredStopAtLevel=1
>> * LockingMode=2 with -XX:-TieredCompilation
>> 
>> Result is consistently similar to Aarch(MacOS) and PPC, All of 124 tests are passing except `MapLoops.java` because in the 2nd part for this testcase, jvm starts with `HeavyMonitors` which conflict with `LockingMode=2`
>
> Amit Kumar has updated the pull request incrementally with one additional commit since the last revision:
> 
>   avoid reloading header after monitor check

Hi @RealLucy, @TheRealMDoerr, @reinrich 
Please review this PR as per your availability. 
Thank you.

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

PR Comment: https://git.openjdk.org/jdk/pull/14414#issuecomment-1588461190