Integrated: 8304824: NMT should not use ThreadCritical

[Robert Toyonaga]

On Wed, 4 Sep 2024 14:17:08 GMT, Robert Toyonaga <duke at openjdk.org> wrote:

> ### Summary
> This PR just replaces `ThreadCritical` with a lock specific to NMT.  `ThreadCritical` is a big lock and is unnecessary for the purposes of NMT. I've implemented the new lock with a semaphore so that it can be used early before VM init.  There is also the possibility of adding assertions in places we expect NMT to have synchronization. I haven't added assertions yet in many places because some code paths such as the (NMT tests)  don't lock yet. I think it makes sense to close any gaps in locking in another PR in which I can also add more assertions. 
> 
> Testing:
> - hotspot_nmt
> - gtest:VirtualSpace
> - tier1

This pull request has now been integrated.

Changeset: 0abfa3ba
Author:    Robert Toyonaga <rtoyonag at redhat.com>
URL:       https://git.openjdk.org/jdk/commit/0abfa3ba8f72538f62be838c1ebac8cfbdd14cdf
Stats:     62 lines in 15 files changed: 19 ins; 21 del; 22 mod

8304824: NMT should not use ThreadCritical

Reviewed-by: stuefe, dholmes, jsjolen

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PR: https://git.openjdk.org/jdk/pull/20852