RFR: 8304824: NMT should not use ThreadCritical [v9]

[Johan Sjölen]

On Mon, 4 Nov 2024 14:52:06 GMT, Robert Toyonaga <duke at openjdk.org> wrote:

>>>This include is not needed because there are no uses that require the definition of Thread.
>> 
>> Right, seems like the forward declaration used to be provided by `memory/allocation.hpp`. Let's get rid of the include and use a forward declaration of our own instead.
>
> Should I open another PR to remove it? I can also remove the locking related to NMT in arena.cpp in the same PR as well (as per [this comment](https://github.com/openjdk/jdk/pull/20852#issuecomment-2450515494)).

I've fixed that particular bug and integrated it already :-).

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PR Review Comment: https://git.openjdk.org/jdk/pull/20852#discussion_r1827882920