Re: [PATCH 3/3] selftests/mm: restore enable_soft_offline in hugetlb-soft-offline

Hi,

On Wed, Aug 12, 2026 at 08:08:21PM +0800, Song Hu wrote:
> hugetlb-soft-offline toggles /proc/sys/vm/enable_soft_offline between 1 and
> 0 (test_soft_offline_common(1) then (0)) and leaves it at 0 when it
> finishes, silently disabling soft offlining for the whole system after the
> run.  Read the original value before the test and restore it before
> ksft_finished().
> 
> Signed-off-by: Song Hu <[email protected]>
> ---
>  .../selftests/mm/hugetlb-soft-offline.c       | 24 +++++++++++++++++++
>  1 file changed, 24 insertions(+)
> 
> diff --git a/tools/testing/selftests/mm/hugetlb-soft-offline.c b/tools/testing/selftests/mm/hugetlb-soft-offline.c
> index bc202e4ed2bd..35dcf661b091 100644
> --- a/tools/testing/selftests/mm/hugetlb-soft-offline.c
> +++ b/tools/testing/selftests/mm/hugetlb-soft-offline.c
> @@ -99,6 +99,23 @@ static int set_enable_soft_offline(int value)
>  	return 0;
>  }
>  
> +static int get_enable_soft_offline(void)
> +{
> +	FILE *fp = fopen("/proc/sys/vm/enable_soft_offline", "r");
> +	int value = -1;
> +
> +	if (!fp) {
> +		ksft_perror(EPREFIX "failed to read enable_soft_offline");
> +		return -1;
> +	}
> +	if (fscanf(fp, "%d", &value) != 1) {
> +		ksft_perror(EPREFIX "failed to parse enable_soft_offline");
> +		value = -1;
> +	}
> +	fclose(fp);
> +	return value;
> +}

We have read_num() in vm_util and write_num() that can replace
set_enable_soft_offline().

> +
>  static int create_hugetlbfs_file(struct statfs *file_stat)
>  {
>  	int fd;
> @@ -185,6 +202,8 @@ static void test_soft_offline_common(int enable_soft_offline)
>  
>  int main(int argc, char **argv)
>  {
> +	int orig;

Please spell out what orig is this.

> +
>  	ksft_print_header();
>  
>  	if (!hugetlb_setup_default(8))
> @@ -192,8 +211,13 @@ int main(int argc, char **argv)
>  
>  	ksft_set_plan(2);
>  
> +	orig = get_enable_soft_offline();
> +
>  	test_soft_offline_common(1);
>  	test_soft_offline_common(0);
>  
> +	if (orig >= 0)
> +		set_enable_soft_offline(orig);
> +
>  	ksft_finished();
>  }
> -- 
> 2.43.0
> 

-- 
Sincerely yours,
Mike.