RFR: JDK-8321266: Add diagnostic RSS threshold [v2]

[David Holmes]

On Tue, 5 Dec 2023 09:43:21 GMT, Thomas Stuefe <stuefe at openjdk.org> wrote:

>> src/hotspot/os/bsd/os_bsd.cpp line 1473:
>> 
>>> 1471:     result = info.resident_size;
>>> 1472:   }
>>> 1473: #endif // __APPLE__
>> 
>> Hmmm so no general BSD support either ...
>
> It is possible on BSD (e.g. using [kvm_getprocs](https://man.freebsd.org/cgi/man.cgi?query=kvm_getprocs&sektion=3&n=1) ) - however, I am no BSD expert and have no system to build BSD on.
> 
> Note that in both cases - AIX and the BSDs - I am not better nor worse than other code that reads RSS, e.g. jfr_report_memory_info(). Which, btw, is a code unification possibility I plan on following up on in a separate RFE (reusing get_rss for use cases such as jfr_report_memory_info).

I don't like seeing disparity in platform support like this but understand we can't always supply the details for every port on the initial integration. I would like to see RFE's filed to have the missing details provided on those platforms so that the respective port maintainers  know there is something missing. I suspect that is not the case with `jfr_report_memory_info`.

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PR Review Comment: https://git.openjdk.org/jdk/pull/16938#discussion_r1416684558