On Fri, May 10, 2019 at 7:49 AM Knut Omang <knut.omang(a)oracle.com> wrote:
On Thu, 2019-05-09 at 22:18 -0700, Frank Rowand wrote:
> On 5/9/19 4:40 PM, Logan Gunthorpe wrote:
> > On 2019-05-09 5:30 p.m., Theodore Ts'o wrote:
> >> On Thu, May 09, 2019 at 04:20:05PM -0600, Logan Gunthorpe wrote:
> >>> The second item, arguably, does have significant overlap with
> >>> Whether you are running short tests in a light weight UML environment
> >>> higher level tests in an heavier VM the two could be using the same
> >>> framework for writing or defining in-kernel tests. It *may* also be
> >>> for some people to be able to run all the UML tests in the heavy VM
> >>> environment along side other higher level tests.
> >>> Looking at the selftests tree in the repo, we already have similar
> >>> what Kunit is adding as I described in point (2) above.
> >>> contains macros like EXPECT_* and ASSERT_* with very similar intentions
> >>> the new KUNIT_EXECPT_* and KUNIT_ASSERT_* macros.
> >>> However, the number of users of this harness appears to be quite small.
> >>> of the code in the selftests tree seems to be a random mismash of
> >>> and userspace code so it's not hard to see it as something
> >>> different from the new Kunit:
> >>> $ git grep --files-with-matches kselftest_harness.h *
> >> To the extent that we can unify how tests are written, I agree that
> >> this would be a good thing. However, you should note that
> >> kselftest_harness.h is currently assums that it will be included in
> >> userspace programs. This is most obviously seen if you look closely
> >> at the functions defined in the header files which makes calls to
> >> fork(), abort() and fprintf().
> > Ah, yes. I obviously did not dig deep enough. Using kunit for
> > in-kernel tests and kselftest_harness for userspace tests seems like
> > a sensible line to draw to me. Trying to unify kernel and userspace
> > here sounds like it could be difficult so it's probably not worth
> > forcing the issue unless someone wants to do some really fancy work
> > to get it done.
> > Based on some of the other commenters, I was under the impression
> > that kselftests had in-kernel tests but I'm not sure where or if they
> > exist.
> YES, kselftest has in-kernel tests. (Excuse the shouting...)
> Here is a likely list of them in the kernel source tree:
> $ grep module_init lib/test_*.c
> lib/test_hash.c:module_init(test_hash_init); /* Does everything */
> lib/test_module.c:static int __init test_module_init(void)
> lib/test_overflow.c:static int __init test_module_init(void)
> > If they do exists, it seems like it would make sense to
> > convert those to kunit and have Kunit tests run-able in a VM or
> > baremetal instance.
> They already run in a VM.
> They already run on bare metal.
> They already run in UML.
> This is not to say that KUnit does not make sense. But I'm still trying
> to get a better description of the KUnit features (and there are
FYI, I have a master student who looks at converting some of these to KTF, such as for
instance the XArray tests, which lended themselves quite good to a semi-automated
The result is also a somewhat more compact code as well as the flexibility
provided by the Googletest executor and the KTF frameworks, such as running selected
tests, output formatting, debugging features etc.
So is KTF already in upstream? Or is the plan to unify the KTF and
Kunit in-kernel test harnesses? Because there's tons of these
in-kernel unit tests already, and every merge we get more (Frank's
list didn't even look into drivers or anywhere else, e.g. it's missing
the locking self tests I worked on in the past), and a more structured
approach would really be good.
Software Engineer, Intel Corporation
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