Re: [PATCH 06/16] selftests/mm: add khugepaged race harness

[Mike Rapoport]

> Collapse serializes against faults, GUP, fork, mremap and zapping
> through a protocol of locks, TLB flushes and refcount checks; none of
> the khugepaged selftests exercise it under contention.
> 
> Add khugepaged_race: two faulters, MADV_DONTNEED, transient FOLL_PIN
> (gup_test), fork and mremap threads race one of three collapse
> drivers over the same ranges:
> 
>   stepped   khugepaged driven one full pass at a time via
>             khugepaged_full_pass() — deterministic extent per step;
>   free      free-running khugepaged (scan_sleep_millisecs=0) — soak;
>   madvise   MADV_COLLAPSE + MADV_DONTNEED loop — the PMD-order axis.
> 
> diff --git a/tools/testing/selftests/mm/run_vmtests.sh b/tools/testing/selftests/mm/run_vmtests.sh
> index 6f42e35b5227..a8b6b839cb97 100755
> --- a/tools/testing/selftests/mm/run_vmtests.sh
> +++ b/tools/testing/selftests/mm/run_vmtests.sh
> @@ -404,6 +404,13 @@ CATEGORY="cow" run_test ./cow
>  
>  CATEGORY="thp" run_test ./folio_order_check
>  
> +
> +CATEGORY="thp" run_test ./khugepaged_race -d 5 -m stepped
> +
> +CATEGORY="thp" run_test ./khugepaged_race -d 5 -m free
> +
> +CATEGORY="thp" run_test ./khugepaged_race -d 5 -m madvise

Please set the default duration so it will be 5 seconds for each mode
and make ./khugepaged_race run all the modes by default.

-- 
Sincerely yours,
Mike.