RFR: 8281946: VM.native_memory should report size of shareable memory [v3]

[Ioi Lam]

On Thu, 15 Dec 2022 04:26:52 GMT, Matias Saavedra Silva <matsaave at openjdk.org> wrote:

>>> > We should instead just use MAP_SHARED flag for ro sections.
>>> 
>>> To clarify, if the ro sections don't require relocation, use MAP_SHARED, else use MAP_PRIVATE.
>> 
>> I am not sure why we use MAP_PRIVATE + PROT_READ for CDS. Maybe it just happened to work so we end up doing it that way. I filed https://bugs.openjdk.org/browse/JDK-8298216 , quoting your suggestions from the previous comments.
>
> Thank you for your patience and reviews @iklam and @tstuefe! I re-ran tier1 tests and the macos-x64 tests pass, so I think we can safely ignore GHA here.

@matias9927 Thank you for taking our suggestions and going through many revisions. I think the result is good.

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PR: https://git.openjdk.org/jdk/pull/11401