RFR: 8234930: Use MAP_JIT when allocating pages for code cache on macOS [v5]

[Anton Kozlov]

On Tue, 13 Oct 2020 13:10:13 GMT, Thomas Stuefe <stuefe at openjdk.org> wrote:

> Are there any users of executable memory which cannot live with anonymous mapping on whatever address with small pages?
> Does anyone need large pages or a specific wish address?

Nothing jumps out immediately.
Recently we've come across CDS problems, which also requires executable permissions, but it uses file-based mapping and
os::map_memory.

> If not, maybe we really should introduce a (reserve|commit|uncommit|release)_executable_memory() at least temporarily,
> as you suggested. At least that would be clear, and could provide a clear starting point for a new interface.

Then I'll start doing this. I'll create another JBS issue for the interface closer to the point when it is ready.

Thanks!

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PR: https://git.openjdk.java.net/jdk/pull/294