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

在 2026/8/12 21:42, Mike Rapoport 写道:
> 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().
> 
Will switch to them in v2 and drop both helpers.
>> +
>>  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.
> 
Will rename to orig_enable_soft_offline.

Also, per the error-path issue Andrew pointed out, v2 will register the
restore with atexit() so it also runs when the test exits via
ksft_exit_fail_msg(), like hugepage_restore_settings_atexit() in
hugepage_settings.c.

Thanks,
Song>> +
>>  	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
>>
>