RFR: 8335091: NMT: VMATree reserve_mapping and commit_mapping APIs need MEMFLAGS while un/-committing API has no MEMFLAGS arg [v3]

[Afshin Zafari]

On Thu, 25 Jul 2024 17:08:59 GMT, Gerard Ziemski <gziemski at openjdk.org> wrote:

>> Afshin Zafari has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   reserve always use the flag in metadata
>
> test/hotspot/gtest/nmt/test_vmatree.cpp line 178:
> 
>> 176: 
>> 177:       tree.reserve_mapping(0, 100, rd1);
>> 178:       tree.commit_mapping(20, 50, rd2, true); // mtTest flag is to be copied to new nodes, even if it is given as mtNMT.
> 
> When does this happen, that we reserve an overlapping region with a different NMT flag?

Here in this test, I used a different flag to verify that the new flag is not used for the new nodes of the tree. This is testing even if a flag is given but the arg is true, it will be ignored.

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PR Review Comment: https://git.openjdk.org/jdk/pull/20330#discussion_r1693390436