Re: [RFC v4 00/17] kunit: introduce KUnit, the Linux kernel unit testing framework

Brendan Higgins
2019-03-25T22:12:22Z

On Thu, Mar 21, 2019 at 6:12 PM Frank Rowand <frowand.list@gmail.com> wrote:
>
> On 3/21/19 4:33 PM, Brendan Higgins wrote:
> > On Thu, Mar 21, 2019 at 3:27 PM Logan Gunthorpe <logang@deltatee.com> wrote:
> >>
> >>
> >>
> >> On 2019-03-21 4:07 p.m., Brendan Higgins wrote:
> >>> A couple of points, as for needing CONFIG_PCI; my plan to deal with
> >>> that type of thing has been that we would add support for a KUnit/UML
> >>> version that is just for KUnit. It would mock out the necessary bits
> >>> to provide a fake hardware implementation for anything that might
> >>> depend on it. I wrote a prototype for mocking/faking MMIO that I
> >>> presented to the list here[1]; it is not part of the current patchset
> >>> because we decided it would be best to focus on getting an MVP in, but
> >>> I plan on bringing it back up at some point. Anyway, what do you
> >>> generally think of this approach?
> >>
> >> Yes, I was wondering if that might be possible. I think that's a great
> >> approach but it will unfortunately take a lot of work before larger
> >> swaths of the kernel are testable in Kunit with UML. Having more common
> >> mocked infrastructure will be great by-product of it though.
> >
> > Yeah, it's unfortunate that the best way to do something often takes
> > so much longer.
> >
> >>
> >>> Awesome, I looked at the code you posted and it doesn't look like you
> >>> have had too many troubles. One thing that stood out to me, why did
> >>> you need to put it in the kunit/ dir?
> >>
> >> Yeah, writing the code was super easy. Only after, did I realized I
> >> couldn't get it to easily build.
> >
> > Yeah, we really need to fix that; unfortunately, broadly addressing
> > that problem is really hard and will most likely take a long time.
> >
> >>
> >> Putting it in the kunit directory was necessary because nothing in the
> >> NTB tree builds unless CONFIG_NTB is set (see drivers/Makefile) and
> >> CONFIG_NTB depends on CONFIG_PCI. I didn't experiment to see how hard it
> >> would be to set CONFIG_NTB without CONFIG_PCI; I assumed it would be tricky.
> >>
> >>> I am looking forward to see what you think!
> >>
> >> Generally, I'm impressed and want to see this work in upstream as soon
> >> as possible so I can start to make use of it!
> >
> > Great to hear! I was trying to get the next revision out this week,
> > but addressing some of the comments is taking a little longer than
> > expected. I should have something together fairly soon though
> > (hopefully next week). Good news is that next revision will be
> > non-RFC; most of the feedback has settled down and I think we are
> > ready to start figuring out how to merge it. Fingers crossed :-)
> >
> > Cheers
>
> I'll be out of the office next week and will not be able to review.
> Please hold off on any devicetree related files until after I review.

Will do.