Re: [PATCH v5 3/3] kselftest: mm: introduce alloc_isolated_mem()

[David Hildenbrand (Arm)]

> diff --git a/tools/testing/selftests/mm/soft-dirty.c b/tools/testing/selftests/mm/soft-dirty.c
> index 5f278913c4d7..b6fad38c8bee 100644
> --- a/tools/testing/selftests/mm/soft-dirty.c
> +++ b/tools/testing/selftests/mm/soft-dirty.c
> @@ -92,9 +92,9 @@ static void test_hugepage(int pagemap_fd, int pagesize)
>  	if (!hpage_len)
>  		ksft_exit_fail_msg("Reading PMD pagesize failed");
>  
> -	map = memalign(hpage_len, hpage_len);
> +	map = alloc_isolated_mem(hpage_len, hpage_len);
>  	if (!map)
> -		ksft_exit_fail_msg("memalign failed\n");
> +		ksft_exit_fail_msg("alloc_isolated_mem failed\n");
>  
>  	ret = madvise(map, hpage_len, MADV_HUGEPAGE);
>  	if (ret)
> @@ -130,7 +130,7 @@ static void test_hugepage(int pagemap_fd, int pagesize)
>  		ksft_test_result_skip("Test %s huge page allocation\n", __func__);
>  		ksft_test_result_skip("Test %s huge page dirty bit\n", __func__);
>  	}
> -	free(map);
> +	free_isolated_mem(map, hpage_len);
>  }

smaps is really only problematic with merged VMAs when relying on exact page
statistics. For other properties (vm flags, MMUPageSize) it's not a problem as
long as our smap search just finds the VMA that covers an address.

Assuming we fixed check_huge_anon() to not use smaps, why is this change here
required?

-- 
Cheers,

David