Re: [PATCH v3 3/3] selftests: pidfd: add tests for PIDFD_SELF_*

[John Hubbard <jhubbard@nvidia.com>]

On 10/16/24 3:06 PM, Lorenzo Stoakes wrote:
> On Wed, Oct 16, 2024 at 02:00:27PM -0600, Shuah Khan wrote:
>> On 10/16/24 04:20, Lorenzo Stoakes wrote:
...
>>> diff --git a/tools/testing/selftests/pidfd/pidfd.h b/tools/testing/selftests/pidfd/pidfd.h
>>> index 88d6830ee004..1640b711889b 100644
>>> --- a/tools/testing/selftests/pidfd/pidfd.h
>>> +++ b/tools/testing/selftests/pidfd/pidfd.h
>>> @@ -50,6 +50,14 @@
>>>    #define PIDFD_NONBLOCK O_NONBLOCK
>>>    #endif
>>> +/* System header file may not have this available. */
>>> +#ifndef PIDFD_SELF_THREAD
>>> +#define PIDFD_SELF_THREAD -100
>>> +#endif
>>> +#ifndef PIDFD_SELF_THREAD_GROUP
>>> +#define PIDFD_SELF_THREAD_GROUP -200
>>> +#endif
>>> +
>>
>> As mentioned in my response to v1 patch:
>>
>> kselftest has dependency on "make headers" and tests include
>> headers from linux/ directory
> 
> Right but that assumes you install the kernel headers on the build system,
> which is quite a painful thing to have to do when you are quickly iterating
> on a qemu setup.
> 
> This is a use case I use all the time so not at all theoretical.
> 

This is turning out to be a fairly typical reaction from kernel
developers, when presented with the "you must first run make headers"
requirement for kselftests.

Peter Zijlstra's "NAK NAK NAK" response [1] last year was the most
colorful, so I'll helpfully cite it here. :)

But seriously...user feedback is rare and valuable. We have some, to the
effect of, "lose that requirement". And we also have an agreement, and
an initial implementation in selftests/mm, on *how* to avoid it [2].

So...let's do it that way? Please?


[1] https://lore.kernel.org/lkml/20231103121652.GA6217@noisy.programming.kicks-ass.net/
[2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e076eaca5906

thanks,
-- 
John Hubbard