Integrated: 8291945: Add OSInfo API for static OS information

[Ioi Lam]

On Thu, 4 Aug 2022 23:18:35 GMT, Ioi Lam <iklam at openjdk.org> wrote:

> As suggested by @tstuefe in the review of #9600, many of the `os` APIs simply return a value that was initialized during VM start up. E.g., `os::vm_page_size()`. I have added a new class `OSInfo` for managing such info
> 
> - Simplifies the per-OS implementation
> - Make the "init-only-once" check consistent
> - In some cases, the simpler `OSInfo` class can be used in lieu of the more complex `os` class. This improves HotSpot build time (e.g., relocInfo.hpp).
> 
> Note: I moved only 2 fields in this PR as a first step. If this works well I plan to move more fields in the future.

This pull request has now been integrated.

Changeset: 9bfffa08
Author:    Ioi Lam <iklam at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/9bfffa082e85372ec39a0fdab6d5f2c175162246
Stats:     213 lines in 17 files changed: 108 ins; 68 del; 37 mod

8291945: Add OSInfo API for static OS information

Reviewed-by: dholmes, stuefe

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PR: https://git.openjdk.org/jdk/pull/9758