RFR: 8366457: Add ResourceArea and Arena allocators for the RBTree

[Johan Sjölen]

On Fri, 9 Jan 2026 11:56:25 GMT, Casper Norrbin <cnorrbin at openjdk.org> wrote:

>> This PR adds Arena and ResourceArea allocators to the RBTree. The test checks that we can make RBTrees from these allocators and that a basic upsert works.
>
> src/hotspot/share/utilities/rbTree.hpp line 35:
> 
>> 33: #include "nmt/memTag.hpp"
>> 34: #include "runtime/os.hpp"
>> 35: #include "runtime/thread.hpp"
> 
> Do we need to include `allocation.hpp` and `thread.hpp`? I can't find what's using these and it builds fine for me with those includes removed.

We need `allocation.hpp` as that provides AllocFailStrategy, etc. `thread.hpp` isn't needed, that was unfortunate left overs from my first draft.

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PR Review Comment: https://git.openjdk.org/jdk/pull/29082#discussion_r2682541106