RFR: 8350567: NMT: update VMATree::register_mapping to copy the existing tag of the region [v2]

[Johan Sjölen]

On Thu, 27 Feb 2025 12:37:31 GMT, Johan Sjölen <jsjolen at openjdk.org> wrote:

>> Afshin Zafari has updated the pull request incrementally with two additional commits since the last revision:
>> 
>>  - removed extra whitespace.
>>  - unit test added.
>
> test/hotspot/gtest/nmt/test_vmatree.cpp line 728:
> 
>> 726: }
>> 727: 
>> 728: TEST_VM_F(NMTVMATreeTest, CommitUseFlagInplace) {
> 
> Change this test to use `expect_equivalent_form`, see other usages to see what should look like. You can add multiple checks even, so that we get how the range changes over time.

Is the bug actually in the summary accounting? If so, I'd like to see a better test name here that indicates that and *not* change this to `expect_equivalent_form` and so on.

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PR Review Comment: https://git.openjdk.org/jdk/pull/23771#discussion_r1976707081