RFR: 8351661: NMT: VMATree should support separate call-stacks for reserve and commit operations [v25]

[Gerard Ziemski]

On Mon, 12 May 2025 11:21:41 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 27 additional commits since the last revision:
> 
>  - Merge remote-tracking branch 'origin/master' into _8351661_separate_call_stack_reserve_commit
>  - fixed one case.
>  - test with random requests passes now.
>  - semantic text added.
>  - more tests for full coverage of update_region.
>  - fixes for cross-compilations
>  - removed print_on for release build success.
>  - complete code coverage for new impl. All tests pass.
>  - new version. All tests except one passed.
>  - second try
>  - ... and 17 more: https://git.openjdk.org/jdk/compare/90f4d0b8...043c11d6

We have a single state denoting free region currently in vmatree, i.e.`State::Released` - should we make a distinction between: never touched and free vs released and free ?

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PR Comment: https://git.openjdk.org/jdk/pull/24028#issuecomment-2877335392