RFR: 8277946: NMT: Deprecate and remove VM.native_memory shutdown jcmd command option

[David Holmes]

On Tue, 30 Nov 2021 15:17:10 GMT, Zhengyu Gu <zgu at openjdk.org> wrote:

> NMT shutdown functionality is a remnant of its first implementation, which could consume excessive amount of memory, therefore, it needed capability to shut it self down to ensure health of JVM. This is no longer a case for new implementation.
> 
> NMT shutdown can be requested via Jcmd. However, it is rare used.
> 
> We should deprecate for shutdown Jcmd command for removing NMT shutdown functionality.
> 
> Corresponding [CSR](https://bugs.openjdk.java.net/browse/JDK-8277947) has been approved.

Hi Zhengyu,

I am fine with removal of the shutdown option of the jcmd as presented, but as per the CSR request I think "Deprecate" has to be removed from this as nothing has been deprecated.

I'm not at all clear why the actual shutdown mechanics removal has been deferred to another issue - that would make sense if this PR actually just deprecated something, but as it is I would have expected everything to go. With RDP1 upon us I assume the actual removal will now be in 19.

Thanks,
David

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Marked as reviewed by dholmes (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/6618