Re: [PATCH v6 3/3] selftests/mm: add new selftests for KSM

[Stefan Roesch <shr@devkernel.io>]

David Hildenbrand <david@redhat.com> writes:

> On 13.04.23 15:07, David Hildenbrand wrote:
>> On 12.04.23 05:16, Stefan Roesch wrote:
>>> This adds three new tests to the selftests for KSM.  These tests use the
>>> new prctl API's to enable and disable KSM.
>>>
>>> 1) add new prctl flags to prctl header file in tools dir
>>>
>>>      This adds the new prctl flags to the include file prct.h in the
>>>      tools directory.  This makes sure they are available for testing.
>>>
>>> 2) add KSM prctl merge test
>>>
>>>      This adds the -t option to the ksm_tests program.  The -t flag
>>>      allows to specify if it should use madvise or prctl ksm merging.
>>>
>>> 3) add KSM get merge type test
>>>
>>>      This adds the -G flag to the ksm_tests program to query the KSM
>>>      status with prctl after KSM has been enabled with prctl.
>>>
>>> 4) add KSM fork test
>>>
>>>      Add fork test to verify that the MMF_VM_MERGE_ANY flag is inherited
>>>      by the child process.
>>>
>>> 5) add two functions for debugging merge outcome
>>>
>>>      This adds two functions to report the metrics in /proc/self/ksm_stat
>>>      and /sys/kernel/debug/mm/ksm.
>>>
>>> The debugging can be enabled with the following command line:
>>> make -C tools/testing/selftests TARGETS="mm" --keep-going \
>>>           EXTRA_CFLAGS=-DDEBUG=1
>> Would it make sense to instead have a "-D" (if still unused) runtime
>> options to print this data? Dead code that's not compiled is a bit
>> unfortunate as it can easily bit-rot.
>> This patch essentially does two things
>> 1) Add the option to run all tests/benchmarks with the PRCTL instead of
>> MADVISE
>> 2) Add some functional KSM tests for the new PRCTL (fork, enabling
>> works, disabling works).
>> The latter should rather go into ksm_functional_tests().
>
>
> "tools/testing/selftests/mm/ksm_functional_tests.c" is what I wanted to say.

I understood. I'll look into moving the fork check and the disabling
into the functional tests for the next version.