RFR: 8337217: Port VirtualMemoryTracker to use VMATree

[Afshin Zafari]

On Fri, 9 Aug 2024 15:05:59 GMT, Johan Sjölen <jsjolen at openjdk.org> wrote:

>> src/hotspot/share/nmt/regionsTree.hpp line 46:
>> 
>>> 44:   using Node = VMATree::TreapNode;
>>> 45: 
>>> 46:   class NodeHelper : public Node {
>> 
>> This shouldn't inherit from `Node` and then have each instance be cast into `NodeHelper`. Make into `class Utils : public AllStatic`.
>
> Alternatively create it by composition:
> 
> ```c++
> class NodeHelper {
>   Node& node;
>   NodeHelper(Node* node) : node(*node) {}
>   // All of the methods
> };
> 
> { // Some Node* node
>   NodeHelper nh(node);
>   // Use nh 
> }

Done. The alternative way.

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PR Review Comment: https://git.openjdk.org/jdk/pull/20425#discussion_r1713462208