RFR: 8256155: Allow multiple large page sizes to be used on Linux [v37]

[Thomas Stuefe]

On Mon, 17 May 2021 21:04:37 GMT, Marcus G K Williams <mgkwill at openjdk.org> wrote:

>> Change the meaning of LargePageSizeInBytes to be the maximum large page size the JVM may use (not the only one). A default value of zero will mean to allow the JVM use large page sizes up to the system's default large page size.
>
> Marcus G K Williams has updated the pull request incrementally with one additional commit since the last revision:
> 
>   kstefanj review comments
>   
>   Signed-off-by: Marcus G K Williams <marcus.williams at intel.com>

src/hotspot/os/linux/os_linux.cpp line 3751:

> 3749:     UseTransparentHugePages = false;
> 3750:     UseHugeTLBFS = false;
> 3751:     UseSHM = false;

Suggestion:

    UseSHM = false;
    if (!FLAG_IS_DEFAULT(UseLargePages)) {
      log_warning(pagesize)("UseLargePages disabled, no large pages configured and available on the system.");
    }
    UseLargePages = false;

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