RFR: 8346123: [REDO] NMT should not use ThreadCritical [v5]

[Kim Barrett]

On Tue, 17 Dec 2024 13:45:38 GMT, Robert Toyonaga <duke at openjdk.org> wrote:

>> `MutexLockerImpl` was not intended for external subclassing, but as the internal base class for `MutexLocker`, and `ConditionalMutexLocker`.  CML was provided for exactly this kind of situation: conditionally locking the mutex.
>
> Ok I see. I will stop using `ConditionalMutexLocker` as a base class. Instead, I'll just get rid of `NmtVirtualMemoryLocker` and use `ConditionalMutexLocker` directly.

Regarding use of `MutexLockerImpl`, perhaps, though I see nothing in the JBS
issue or the PR that says that.  If it's the name that drives that position
then I think it can easily be argued that it's misnamed, and should be
something like MutexLockerBase.  It *is* nicely designed for use as a base
class, with protected ctors/dtor, making it a convient basis for lockers for
specific use cases. But see my other response about how to has-a use CML (and
MutexLocker) for that purpose.

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PR Review Comment: https://git.openjdk.org/jdk/pull/22745#discussion_r1890769789