RFR: 8337217: Port VirtualMemoryTracker to use VMATree [v33]

[Afshin Zafari]

On Mon, 3 Mar 2025 20:06:20 GMT, Gerard Ziemski <gziemski at openjdk.org> wrote:

>> Afshin Zafari has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   style, some cleanup, VMT and regionsTree circular dep resolved
>
> test/hotspot/gtest/nmt/test_regions_tree.cpp line 102:
> 
>> 100:   rt.commit_region((address)1030, 5UL, ncs);
>> 101:   rt.commit_region((address)1040, 5UL, ncs);
>> 102:   ReservedMemoryRegion rmr((address)1000, 50);
> 
> I would add something like:
> 
>   rt.commit_region((address)1500, 5UL, ncs); // should not be counted
> 
> that should not be counted.

adding that line crashes for me as follows:

Internal Error (<local-path>/src/hotspot/share/nmt/vmatree.cpp:77), pid=87926, tid=87926
#  assert(leqA_n->val().out.type() != StateType::Released) failed: Should not use inplace the tag of a released region
#

It means that we cannot commit without reserving first. The region being committed is released but should be reserved.

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/20425#discussion_r1979080504