RFR: JDK-8318636: Add jcmd to print annotated process memory map [v3]

[Thomas Stuefe]

On Fri, 27 Oct 2023 09:42:19 GMT, Johan Sjölen <jsjolen at openjdk.org> wrote:

>> Thomas Stuefe has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains four commits:
>> 
>>  - Merge master and solve merge conflicts
>>  - small fixes
>>  - start from VM op; show more thread details
>>  - start
>
> Hi,
> 
> Thank you for this PR. These comments are just a first pass, I haven't finished going through the code.

@jdksjolen Many thanks for the review. I fixed most of your requests, and also added a simple timeout fuse to prevent the printing from taking overly long in the rare case of insanely large or fragmented process memory maps.

> src/hotspot/os/linux/memMapPrinter_linux.cpp line 32:
> 
>> 30: #include "utilities/globalDefinitions.hpp"
>> 31: 
>> 32: struct proc_maps_info_t {
> 
> `struct ProcMapsInfo` please. The `_t` is apparently reserved for POSIX, and I prefer our structs and classes to not look like they're coming from a C library anyway.

ok

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PR Comment: https://git.openjdk.org/jdk/pull/16301#issuecomment-1782829434
PR Review Comment: https://git.openjdk.org/jdk/pull/16301#discussion_r1374499761