RFR: 8351661: NMT: VMATree should support separate call-stacks for reserve and commit operations [v13]

[Johan Sjölen]

On Wed, 23 Apr 2025 07:57:13 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 with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 14 additional commits since the last revision:
> 
>  - Merge remote-tracking branch 'origin/master' into _8351661_separate_call_stack_reserve_commit
>  - one more test case for overlapping multiple regions
>  - 10 cases added for overlapping with multiple regions
>  - 24 test-cases added for full coverage of cases.
>  - fixed format of the missed Pre
>  - Pre conditions are also visualized.
>  - fixes. New check_tree impl and visualization.
>  - fix the GHA failures.
>  - improvements
>  - more fixes.
>  - ... and 4 more: https://git.openjdk.org/jdk/compare/cf0e26d0...b8b40862

test/hotspot/gtest/nmt/test_vmatree.cpp line 1928:

> 1926:     //                                                   Rl                                                     Rs          Rl
> 1927:     //                                                   -                                                      si_1        -
> 1928:     //                                                   -                                                      -           -

Why isn't there a reserved region between `[0, 50)` also after this?

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PR Review Comment: https://git.openjdk.org/jdk/pull/24028#discussion_r2055657669