RFR: 8351661: NMT: VMATree should support separate call-stacks for reserve and commit operations [v9]

[Gerard Ziemski]

On Tue, 8 Apr 2025 08:28:09 GMT, Afshin Zafari <azafari at openjdk.org> wrote:

>> In NMT detail mode, we need to have separate call-stacks for Reserve and Commit operations.
>> This PR adds a second stack to every node that will be used when committing (and uncommitting) the start node of a reserved region.
>
> Afshin Zafari has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Pre conditions are also visualized.

Changes requested by gziemski (Reviewer).

test/hotspot/gtest/nmt/test_vmatree.cpp line 975:

> 973: 
> 974:     tree.uncommit_mapping(0, 5, call_stack_2);
> 975:     // Pre:  .........0********10--------20********40-------100.........

I think this one got lost, still could use reformatting:

`// Pre:  .........0*****************10--------20********40-------100.........`

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PR Review: https://git.openjdk.org/jdk/pull/24028#pullrequestreview-2751160750
PR Review Comment: https://git.openjdk.org/jdk/pull/24028#discussion_r2033883257