RFR: 8331539: [REDO] NMT: add/make a mandatory MEMFLAGS argument to family of os::reserve/commit/uncommit memory API [v2]

[Afshin Zafari]

On Fri, 24 May 2024 10:10:08 GMT, Thomas Stuefe <stuefe at openjdk.org> wrote:

> 1. NMT assumes reserves and commits to be different layers and, e.g., for committed regions to be fully contained in a reserved region. This is wrong and does not reflect the realities of mmap. We can overlay and overlap any reservation/committing/uncommitting/releasing in any way we want.

On Windows, a commit without reserve is not allowed. ([reference](https://learn.microsoft.com/en-us/windows/win32/api/memoryapi/nf-memoryapi-virtualalloc#:~:text=MEM_COMMIT%20%7C%20MEM_RESERVE.-,Attempting%20to%20commit%20a%20specific%20address%20range%20by%20specifying%20MEM_COMMIT%20without%20MEM_RESERVE%20and%20a%20non%2DNULL%20lpAddress%20fails%20unless%20the%20entire%20range%20has%20already%20been%20reserved.%20The%20resulting%20error%20code%20is%20ERROR_INVALID_ADDRESS.,-An%20attempt%20to))

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PR Comment: https://git.openjdk.org/jdk/pull/19343#issuecomment-2129603425