RFR: 8272788: Nonleaf ranked locks should not be safepoint_check_never [v3]

[Coleen Phillimore]

On Wed, 1 Sep 2021 17:27:33 GMT, Patricio Chilano Mateo <pchilanomate at openjdk.org> wrote:

>> Coleen Phillimore has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains four commits:
>> 
>>  - Fix merge error.
>>  - Merge branch 'master' into nonleaf
>>  - Remove JfrSream_lock and rerun JFR tests.
>>  - 8272788: Nonleaf ranked locks should not be safepoint_check_neve
>
> src/hotspot/share/runtime/mutexLocker.cpp line 270:
> 
>> 268: 
>> 269:   def(Threads_lock                 , PaddedMonitor, barrier,     true,  _safepoint_check_always);  // Used for safepoint protocol.
>> 270:   def(NonJavaThreadsList_lock      , PaddedMutex,   leaf+1,      true,  _safepoint_check_never);
> 
> Why do we need to change this rank? We now assert a lock should be _safepoint_check_always if the rank is >= nonleaf, but this is barrier so it should be good.

This was leftover from a different change where I was trying to move all the _safepoint_check_never locks to leaf level.  In any case, I reverted this change and am retesting tier1-3.

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PR: https://git.openjdk.java.net/jdk/pull/5203