Re: [PATCH for-next v3 1/9] slub_kunit: fall back to SW perf events when HW PMU is not available

[Harry Yoo]

On 6/15/26 8:05 PM, Harry Yoo (Oracle) wrote:
> slub_kunit uses hardware perf events to invoke _nolock() APIs from NMI
> context. However, creating a HW perf event fails when there is no
> hardware PMU, or when running in a virtualized environment without a
> virtual PMU configured.
> 
> Since tests are often performed in virtualized environments, fall back
> to a SW perf event so that the test can still run, even if it cannot
> cover IRQ-disabled sections.
> 
> For the sheaves path, IRQs are not disabled until the barn is accessed.
> So some coverage is still expected.
> 
> Signed-off-by: Harry Yoo (Oracle) <harry@xxxxxxxxxx>
> ---
>  lib/tests/slub_kunit.c | 70 +++++++++++++++++++++++++++++++++++++++-----------
>  1 file changed, 55 insertions(+), 15 deletions(-)
> 
> diff --git a/lib/tests/slub_kunit.c b/lib/tests/slub_kunit.c
> index fa6d31dbca16..11255fc8eb78 100644
> --- a/lib/tests/slub_kunit.c
> +++ b/lib/tests/slub_kunit.c
> @@ -303,6 +303,7 @@ struct test_nolock_context {
>  	int alloc_ok;
>  	int alloc_fail;
>  	struct perf_event *event;
> +	bool is_perf_type_hw;
>  };

nit: should have checked struct perf_event.type instead of introducing
a new field. Will fix.

-- 
Cheers,
Harry / Hyeonggon

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