RFR: 8256155: os::Linux Populate all large_page_sizes, select smallest page size in reserve_memory_special_huge_tlbfs* [v27]

[Stefan Johansson]

On Wed, 21 Apr 2021 18:00:52 GMT, Marcus G K Williams <github.com+168222+mgkwill at openjdk.org> wrote:

> > > * Do we allow explicit -XX:LargePageSizeInBytes=0 ? Seems somewhat pointless. Do we handle it today?
> 
> > Actually we don't, but we probably should handle it. Would be kind of strange preventing someone from setting the default.
> 
> How should we handle this differently?

I just mean that if `LargePageSizeInBytes=0` on the command line that should give the same result as not setting anything. Right now you get a warning, and the default behavior. The warning should go away since it is documented to mean use the default.

> $ java -XX:+UseLargePages -XX:LargePageSizeInBytes=0 -version
> Java HotSpot(TM) 64-Bit Server VM warning: Setting LargePageSizeInBytes=0 has no effect on this OS. Using the default large page size 2048K.

I also updated the title for the issue in JBS and I suspect that you will get a notification to change it here as well.

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PR: https://git.openjdk.java.net/jdk/pull/1153