[3/3] userfaultfd: selftest: Report XFAIL if shmem doesn't support zeropage
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Message ID 20180725024209.32586-4-bauerman@linux.ibm.com
State New
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Series
  • userfaultfd: selftest: Improve behavior with older kernels
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Commit Message

Thiago Jung Bauermann July 25, 2018, 2:42 a.m. UTC
If userfaultfd runs on a system that doesn't support UFFDIO_ZEROPAGE for
shared memory, it currently ends with error code 1 which indicates test
failure:

  # ./userfaultfd shmem 10 10
  nr_pages: 160, nr_pages_per_cpu: 80
  bounces: 9, mode: rnd poll, unexpected missing ioctl for anon memory
  # echo $?
  1

This is a real failure, but expected so signal that to the test harness:

  # ./userfaultfd shmem 10 10
  nr_pages: 160, nr_pages_per_cpu: 80
  bounces: 9, mode: rnd poll, UFFDIO_ZEROPAGE unsupported in shmem VMAs
  # echo $?
  2

Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
---
 tools/testing/selftests/vm/userfaultfd.c | 8 ++++++++
 1 file changed, 8 insertions(+)


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Comments

Mike Rapoport July 25, 2018, 2:18 p.m. UTC | #1
Hi,

On Tue, Jul 24, 2018 at 11:42:09PM -0300, Thiago Jung Bauermann wrote:
> If userfaultfd runs on a system that doesn't support UFFDIO_ZEROPAGE for
> shared memory, it currently ends with error code 1 which indicates test
> failure:
> 
>   # ./userfaultfd shmem 10 10
>   nr_pages: 160, nr_pages_per_cpu: 80
>   bounces: 9, mode: rnd poll, unexpected missing ioctl for anon memory
>   # echo $?
>   1
> 
> This is a real failure, but expected so signal that to the test harness:

I don't think its a real failure. If the kernel does not support
UFFDIO_ZEROPAGE for shared memory the userfaultfd_zeropage_test can be
simply skipped.
 
>   # ./userfaultfd shmem 10 10
>   nr_pages: 160, nr_pages_per_cpu: 80
>   bounces: 9, mode: rnd poll, UFFDIO_ZEROPAGE unsupported in shmem VMAs
>   # echo $?
>   2
> 
> Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
> ---
>  tools/testing/selftests/vm/userfaultfd.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/tools/testing/selftests/vm/userfaultfd.c b/tools/testing/selftests/vm/userfaultfd.c
> index bc9ec38fbc34..686fe96f617f 100644
> --- a/tools/testing/selftests/vm/userfaultfd.c
> +++ b/tools/testing/selftests/vm/userfaultfd.c
> @@ -1115,6 +1115,14 @@ static int userfaultfd_stress(void)
>  		expected_ioctls = uffd_test_ops->expected_ioctls;
>  		if ((uffdio_register.ioctls & expected_ioctls) !=
>  		    expected_ioctls) {
> +			if (test_type == TEST_SHMEM &&
> +			    (uffdio_register.ioctls & expected_ioctls) ==
> +			    UFFD_API_RANGE_IOCTLS_BASIC) {
> +				fprintf(stderr,
> +					"UFFDIO_ZEROPAGE unsupported in shmem VMAs\n");
> +				return KSFT_XFAIL;
> +			}
> +

By all means, this check should be moved to userfaultfd_zeropage_test().
Ideally, we should call here ksft_test_result_skip() and simply return from
the function.



>  			fprintf(stderr,
>  				"unexpected missing ioctl for anon memory\n");
>  			return 1;
Thiago Jung Bauermann July 31, 2018, 12:01 a.m. UTC | #2
Mike Rapoport <rppt@linux.vnet.ibm.com> writes:

> Hi,
>
> On Tue, Jul 24, 2018 at 11:42:09PM -0300, Thiago Jung Bauermann wrote:
>> If userfaultfd runs on a system that doesn't support UFFDIO_ZEROPAGE for
>> shared memory, it currently ends with error code 1 which indicates test
>> failure:
>>
>>   # ./userfaultfd shmem 10 10
>>   nr_pages: 160, nr_pages_per_cpu: 80
>>   bounces: 9, mode: rnd poll, unexpected missing ioctl for anon memory
>>   # echo $?
>>   1
>>
>> This is a real failure, but expected so signal that to the test harness:
>
> I don't think its a real failure. If the kernel does not support
> UFFDIO_ZEROPAGE for shared memory the userfaultfd_zeropage_test can be
> simply skipped.

Ok, good point. I'll make that change in v2.

>>   # ./userfaultfd shmem 10 10
>>   nr_pages: 160, nr_pages_per_cpu: 80
>>   bounces: 9, mode: rnd poll, UFFDIO_ZEROPAGE unsupported in shmem VMAs
>>   # echo $?
>>   2
>>
>> Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
>> ---
>>  tools/testing/selftests/vm/userfaultfd.c | 8 ++++++++
>>  1 file changed, 8 insertions(+)
>>
>> diff --git a/tools/testing/selftests/vm/userfaultfd.c b/tools/testing/selftests/vm/userfaultfd.c
>> index bc9ec38fbc34..686fe96f617f 100644
>> --- a/tools/testing/selftests/vm/userfaultfd.c
>> +++ b/tools/testing/selftests/vm/userfaultfd.c
>> @@ -1115,6 +1115,14 @@ static int userfaultfd_stress(void)
>>  		expected_ioctls = uffd_test_ops->expected_ioctls;
>>  		if ((uffdio_register.ioctls & expected_ioctls) !=
>>  		    expected_ioctls) {
>> +			if (test_type == TEST_SHMEM &&
>> +			    (uffdio_register.ioctls & expected_ioctls) ==
>> +			    UFFD_API_RANGE_IOCTLS_BASIC) {
>> +				fprintf(stderr,
>> +					"UFFDIO_ZEROPAGE unsupported in shmem VMAs\n");
>> +				return KSFT_XFAIL;
>> +			}
>> +
>
> By all means, this check should be moved to userfaultfd_zeropage_test().

I made that change in v2.

> Ideally, we should call here ksft_test_result_skip() and simply return from
> the function.

In my understanding, calling ksft_test_result_skip() would require
converting the testcase to use the functions that generate TAP output.

Also, returning here isn't actually necessary: from my testing
userfaultfd_stress() doesn't require zeropage support in shmem so if the
only bit missing from uffdio_register.ioctls is the one for
UFFDIO_ZEROPAGE then this error can simply be ignored and the test can
continue. Do you agree?

>>  			fprintf(stderr,
>>  				"unexpected missing ioctl for anon memory\n");
>>  			return 1;


--
Thiago Jung Bauermann
IBM Linux Technology Center

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Patch
diff mbox series

diff --git a/tools/testing/selftests/vm/userfaultfd.c b/tools/testing/selftests/vm/userfaultfd.c
index bc9ec38fbc34..686fe96f617f 100644
--- a/tools/testing/selftests/vm/userfaultfd.c
+++ b/tools/testing/selftests/vm/userfaultfd.c
@@ -1115,6 +1115,14 @@  static int userfaultfd_stress(void)
 		expected_ioctls = uffd_test_ops->expected_ioctls;
 		if ((uffdio_register.ioctls & expected_ioctls) !=
 		    expected_ioctls) {
+			if (test_type == TEST_SHMEM &&
+			    (uffdio_register.ioctls & expected_ioctls) ==
+			    UFFD_API_RANGE_IOCTLS_BASIC) {
+				fprintf(stderr,
+					"UFFDIO_ZEROPAGE unsupported in shmem VMAs\n");
+				return KSFT_XFAIL;
+			}
+
 			fprintf(stderr,
 				"unexpected missing ioctl for anon memory\n");
 			return 1;