RFR: 8366716: Move SmapsParser from runtime/os/TestTracePageSizes.java into testlib

[Stefan Johansson]

On Mon, 15 Sep 2025 06:00:48 GMT, Stefan Karlsson <stefank at openjdk.org> wrote:

> Is this the correct way to verify it?

The problem we had in testing ([JDK-8366980](https://bugs.openjdk.org/browse/JDK-8366980)) was that we saw failures when running with `-XX:-UseCompressedOops` so that should be explicitly verified (`-XX:+UseCompressedOops` is the default). Adding it to the process launcher in the code works for testing, but to test without altering the code you can also pass it in. If you run the tests through make: 

make test TEST=gc/TestTransparentHugePagesHeap.java JTREG="JAVA_OPTIONS=-XX:-UseCompressedOops"


A couple of other comments without doing a proper review is that the new smaps classes should be located along side `HugePageConfiguration` under `lib/os/linux` and I think we want to think about how to structure the classes. Maybe something like this: 

public class Smaps {
    public static class Parser { ... }
    public static class Range { ... }
}

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PR Comment: https://git.openjdk.org/jdk/pull/27273#issuecomment-3290711581