RFR: 8273300: Check Mutex ranking during a safepoint [v4]

[Coleen Phillimore]

On Wed, 15 Sep 2021 01:28:34 GMT, David Holmes <dholmes 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 Shenandoah mismerge
>>  - Merge branch 'master' into checkrank
>>  - Fix Shenandoah mismerge
>>  - 8273300: Check Mutex ranking during a safepoint
>
> src/hotspot/share/runtime/mutex.hpp line 53:
> 
>> 51:        special        = tty            +   3,
>> 52:        oopstorage     = special        +   3,
>> 53:        leaf           = oopstorage     +  10,
> 
> Why do we need such a big gap here? Is there any reason we can't just use the same gap between all named rankings? As it is there seems to be no rationale for the  "+ N" value used.

The gap is pretty much arbitrary, but there's already some leaf-2 and having overlapping rankings is something we don't really want, so I changed it to 10 for now.

> src/hotspot/share/utilities/growableArray.hpp line 2:
> 
>> 1: /*
>> 2:  * Copyright (c) 1997, 2021, Oracle and/or its affiliates. All rights reserved.
> 
> Unwanted copyright change.

I think I finally reverted them.  My commit script fixed them back again.

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PR: https://git.openjdk.java.net/jdk/pull/5467