On 7/29/24 01:55, Muhammad Usama Anjum wrote:
On 7/27/24 12:35 AM, Shuah Khan wrote:
On 7/15/24 04:09, Muhammad Usama Anjum wrote:
Hi Kees and All,
There are several tests in kselftest subsystem which load modules to tests
the internals of the kernel. Most of these test modules are just loaded by
the kselftest, their status isn't read and reported to the user logs. Hence
they don't provide benefit of executing those tests.
I've found patches from Kees where he has been converting such kselftests
to kunit tests [1]. The probable motivation is to move tests output of
kselftest subsystem which only triggers tests without correctly reporting
the results. On the other hand, kunit is there to test the kernel's
internal functions which can't be done by userspace.
Kselftest: Test user facing APIs from userspace
Kunit: Test kernel's internal functions from kernelspace
This brings me to conclusion that kselftest which are loading modules to
test kernelspace should be converted to kunit tests. I've noted several
such kselftests.
This is just my understanding. Please mention if I'm correct above or more
reasons to support kselftest test modules transformation into kunit test.
[1] https://lore.kernel.org/all/20221018082824.never.845-kees@xxxxxxxxxx/
Please make sure you aren't taking away the ability to run these tests during
boot.
The kunit tests are usually run at boot time. They can be run later as
well. So I'm not trying to remove any functionality. Rather adding a way
where failures would actually be detected.
It doesn't make sense to convert every single test especially when it
is intended to be run during boot without dependencies - not as a kunit test
but a regression test during boot.
I started investigating when these lib kselftests were just loading the
test module without checking if test actually passed/failed (which proves
that this type of kselftests can never detect regression as it doesn't
process the results). It was strange. Hence I found out the conversion of
such kselftests to kunit tests done by Kees and started this thread for
discussion before doing actual work and sending patches.
I explained this on two other threads. If you don't know how this test
is used why are you making this change?
bitmap is one example - pay attention to the config help test - bitmap
one clearly states it runs regression testing during boot. Any test that
says that isn't a candidate for conversion.
Please can you explain what do you mean by bitmap testing during boot? As
far as I understand, the kselftests are usespace tests and are run after
kernel has booted completely and userspace has started. It cannot be
regarded as testing during boot.
I responded to David - let me know you would like me to repeat it.
thanks,
-- Shuah
