On 24.06.25 05:27, Li Wang wrote:
> Some systems (e.g. minimal or real-time kernels) may not enable
> Transparent Hugepages (THP), causing MADV_HUGEPAGE to return EINVAL.
> This patch introduces a runtime check using the existing THP sysfs
> interface and skips the hugepage merging test (`-H`) when THP is
> not available.
>
> To avoid those failures:

But we deliberately have in tools/testing/selftests/mm/config:

CONFIG_TRANSPARENT_HUGEPAGE=y

So isn't this rather a test setup issue? Meaning, the environment is
not well prepared.

It's true that CONFIG_TRANSPARENT_HUGEPAGE=y is explicitly

enabled in tools/testing/selftests/mm/config, so ideally the runtime

environment should also support THP.

However, in practice, we've found that on some systems:

- THP is disabled at boot time (transparent_hugepage=never)
- Or manually disabled via sysfs
- Or unavailable in RT kernels, containers, or minimal CI environments

In these cases, the test will fail with EINVAL on madvise(MADV_HUGEPAGE),

even though the kernel config is correct.

To make the test suite more robust and avoid false negatives, this patch

adds a runtime check for /sys/kernel/mm/transparent_hugepage/enabled.

If THP is not available, the hugepage test (-H) is skipped with a clear message.