RFR: JDK-8318636: Add jcmd to print annotated process memory map [v6]

[Johan Sjölen]

On Sat, 28 Oct 2023 13:04:05 GMT, Thomas Stuefe <stuefe at openjdk.org> wrote:

>> Analysts and supporters often use /proc/xx/maps to make sense of the memory footprint of a process.
>> 
>> Interpreting the memory map correctly can help when used as a complement to other tools (e.g. NMT). There even exist tools out there that attempt to annotate the process memory map with JVM information.
>> 
>> That, however, can be more accurately done from within the JVM, at least for mappings originating from hotspot. After all, we can correlate the mapping information in NMT with the VMA map.
>> 
>> Example output (from a spring petstore run):
>> 
>> [example_system_map.txt](https://github.com/openjdk/jdk/files/13179054/example_system_map.txt)
>> 
>> This patch adds the VM annotations for VMAs that are *mmaped*. I also have an experimental patch that works with malloc'ed memory, but it is not ready yet for consumption and I leave that part of for now.
>
> Thomas Stuefe has updated the pull request incrementally with one additional commit since the last revision:
> 
>   fix various builds

src/hotspot/share/nmt/memMapPrinter.cpp line 99:

> 97:   }
> 98: 
> 99:   bool add(const void* from, const void* to, MEMFLAGS f) {

Please mention that we're `add`ing in sorted order, that is that `forall R \in _ranges: R.to <= from` holds.

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PR Review Comment: https://git.openjdk.org/jdk/pull/16301#discussion_r1378589809