Integrated: 8364114: Test TestHugePageDecisionsAtVMStartup.java#LP_enabled fails when no free hugepage

[SendaoYan]

On Fri, 25 Jul 2025 12:47:23 GMT, SendaoYan <syan at openjdk.org> wrote:

> Hi all,
> 
> The test runtime/os/TestHugePageDecisionsAtVMStartup.java#LP_enabled will fails when there is no free hugepases.
> The /proc/meminfo and /sys/kernel/mm/hugepages/hugepages-*/free_hugepages says there is no free hugepage, and the JVM output also say there is available large page.
> 
> 
>> cat /proc/meminfo | grep -i HugePages
> AnonHugePages:         0 kB
> ShmemHugePages:        0 kB
> FileHugePages:         0 kB
> HugePages_Total:       2
> HugePages_Free:        0
> HugePages_Rsvd:        0
> HugePages_Surp:        2
> Hugepagesize:       2048 kB
> 
>> ( set -x ; cat /sys/kernel/mm/hugepages/hugepages-*/free_hugepages )
> + cat /sys/kernel/mm/hugepages/hugepages-1048576kB/free_hugepages /sys/kernel/mm/hugepages/hugepages-2048kB/free_hugepages
> 0
> 0
> 
> JVM output snippet from java -XX:+UseLargePages -Xlog:pagesize -version
> [0.001s][info][pagesize] Large page size (2M) failed sanity check, checking if smaller large page sizes are usable
> [0.001s][warning][pagesize] UseLargePages disabled, no large pages configured and available on the system.
> 
> 
> The JVM can not use large page when there is no available large page on system, it's not a JVM bug. So I think it's not suitable to report test failure, but report SkippedException.
> 
> Change has been verified locally, test report SkippedException on the system without free hugepage, the test passes on the system with free hugepage. Test-fix only, risk is low.

This pull request has now been integrated.

Changeset: 3b0da298
Author:    SendaoYan <syan at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/3b0da29879990e4ed6d22c8aed0659f3b40c37a3
Stats:     32 lines in 2 files changed: 29 ins; 0 del; 3 mod

8364114: Test TestHugePageDecisionsAtVMStartup.java#LP_enabled fails when no free hugepage

Reviewed-by: stuefe, dholmes

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PR: https://git.openjdk.org/jdk/pull/26480