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From: Jeff Xu <jeffxu@chromium.org>
Date: Mon, 10 Jun 2024 21:45:58 -0700
Message-ID: <CABi2SkU8=tjWhD-e=OdiVr+YeU+BZZLB_vMfkNb-VWpbP2xcng@mail.gmail.com>
Subject: Re: [PATCH 0/5] cleanups, fixes, and progress towards avoiding "make headers"
To: John Hubbard <jhubbard@nvidia.com>
Cc: Andrew Morton <akpm@linux-foundation.org>, Shuah Khan <shuah@kernel.org>, 
	Andrei Vagin <avagin@google.com>, Axel Rasmussen <axelrasmussen@google.com>, 
	Christian Brauner <brauner@kernel.org>, David Hildenbrand <david@redhat.com>, Kees Cook <kees@kernel.org>, 
	Kent Overstreet <kent.overstreet@linux.dev>, "Liam R . Howlett" <Liam.Howlett@oracle.com>, 
	Muhammad Usama Anjum <usama.anjum@collabora.com>, Peter Xu <peterx@redhat.com>, 
	Rich Felker <dalias@libc.org>, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, 
	LKML <linux-kernel@vger.kernel.org>
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On Mon, Jun 10, 2024 at 9:34=E2=80=AFPM John Hubbard <jhubbard@nvidia.com> =
wrote:
>
> On 6/10/24 9:21 PM, Jeff Xu wrote:
> > Hi
> >
> >
> > On Fri, Jun 7, 2024 at 7:10=E2=80=AFPM John Hubbard <jhubbard@nvidia.co=
m> wrote:
> >>
> >> Eventually, once the build succeeds on a sufficiently old distro, the
> >> idea is to delete $(KHDR_INCLUDES) from the selftests/mm build, and th=
en
> >> after that, from selftests/lib.mk and all of the other selftest builds=
.
> >>
> >> For now, this series merely achieves a clean build of selftests/mm on =
a
> >> not-so-old distro: Ubuntu 23.04:
> >>
> >> 1. Add __NR_mseal.
> >>
> >> 2. Add fs.h, taken as usual from a snapshot of ./usr/include/linux/fs.=
h
> >> after running "make headers". This is how we have agreed to do this so=
rt
> >> of thing, see [1].
> >>
> > What is the "official" way to build selftests/mm ?
>
>  From Documentation/dev-tools/kselftest.rst, it is:
>
>    $ make headers
>    $ make -C tools/testing/selftests
>
> > I tried a few ways, but it never worked, i.e. due to head missing.
>
> You are correct. Today's rules require "make headers" first. But
> I'm working on getting rid of that requirement, because it causes
> problems for some people and situations.
>
> (Even worse is the follow-up rule, in today's documentation,
> that tells us to *run* the selftests from within Make! This
> is just madness.

That is hilarious! :)

>  Because the tests need to run as root in
> many cases. And Make will try to rebuild if necessary...thus
> filling your tree full of root-owned files...but that's for
> another time.)
>
> >
> > 1>
> > cd tools/testing/selftests/mm
> > make
> >
> > migration.c:10:10: fatal error: numa.h: No such file or directory
> >     10 | #include <numa.h>
> >        |          ^~~~~~~~
> > compilation terminated.
> >
> > 2>
> > make headers
> > make -C tools/testing/selftests
> >
> > make[1]: Entering directory
> > '/usr/local/google/home/jeffxu/mm/tools/testing/selftests/mm'
> >    CC       migration
> > migration.c:10:10: fatal error: numa.h: No such file or directory
> >     10 | #include <numa.h>
> >
>
> Well, actually, for these, one should install libnuma-dev and
> numactl (those are Ubuntu package names. Arch Linux would be:
> numactl).
>
> I think. The idea is: use system headers if they are there, and
> local kernel tree header files if the items are so new that they
> haven't made it to $OLDEST_DISTO_REASONABLE.
>
> Something like that.
>
But I don't want to install random packages if possible.

Can makefile rule continue to the next target in case of failure though ?
right now it stopped  at migration.c , if it continues to the next target, =
then
I don't  need to use gcc to manually build mseal_test.

> So if you systematically install various packages on your machine,
> then apply the various patches that I have floating around, then
> you will be able to build selftests/mm without "make headers", at
> this point. Or so I claim.
>
> thanks,
> --
> John Hubbard
> NVIDIA
>

Thanks
-Jeff