RFR: 8366854: Extend jtreg failure handler with THP info [v2]

[Stefan Karlsson]

On Thu, 4 Sep 2025 07:30:35 GMT, Stefan Johansson <sjohanss at openjdk.org> wrote:

>> Stefan Karlsson has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Add shmem_enabled
>
> test/failure_handler/src/share/conf/linux.properties line 127:
> 
>> 125: memory.proc_vmstat.delimiter=\0
>> 126: memory.thp.app=bash
>> 127: memory.thp.args=-c\0cat /sys/kernel/mm/transparent_hugepage/{enabled,defrag}
> 
> I think we should include `shmem_enabled` and we could use `tail` if we want to see what files have what info. But I don't have a strong feeling about that:
> 
> $ cat /sys/kernel/mm/transparent_hugepage/{enabled,defrag,shmem_enabled}
> always [madvise] never
> always defer defer+madvise [madvise] never
> always within_size advise [never] deny force
> 
> Versus:
> 
> $ tail /sys/kernel/mm/transparent_hugepage/{enabled,defrag,shmem_enabled}
> ==> /sys/kernel/mm/transparent_hugepage/enabled <==
> always [madvise] never
> 
> ==> /sys/kernel/mm/transparent_hugepage/defrag <==
> always defer defer+madvise [madvise] never
> 
> ==> /sys/kernel/mm/transparent_hugepage/shmem_enabled <==
> always within_size advise [never] deny force

I added shmem_enabled but kept cat for now.

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PR Review Comment: https://git.openjdk.org/jdk/pull/27086#discussion_r2321156814