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

[Chris Plummer]

On Mon, 23 Oct 2023 01:39:16 GMT, Chris Plummer <cjplummer 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:
>> 
>> [example.system.map.txt](https://github.com/openjdk/jdk/files/13062903/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.
>
> The hs_err file includes a dump of the maps file. It seems these annotations would be useful there also.

> @plummercj on second thought, I'd rather leave the hs-err part for a follow-up RFE.

That's fine. Thanks for considering it.

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PR Comment: https://git.openjdk.org/jdk/pull/16301#issuecomment-1775661061