linux-kernel - Re: [PATCH] selftests/mm: Dont fail testsuite due to a lack of hugepages

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Date: Mon, 4 Mar 2024 12:08:49 -0700
From: Nico Pache <npache@...hat.com>
To: Muhammad Usama Anjum <usama.anjum@...labora.com>
Cc: linux-mm@...ck.org, linux-kselftest@...r.kernel.org, 
	linux-kernel@...r.kernel.org, ben@...adent.org.uk, shuah@...nel.org, 
	akpm@...ux-foundation.org
Subject: Re: [PATCH] selftests/mm: Dont fail testsuite due to a lack of hugepages

On Fri, Mar 1, 2024 at 2:35 AM Muhammad Usama Anjum
<usama.anjum@...labora.com> wrote:
>
> On 3/1/24 12:33 PM, Nico Pache wrote:
> > On systems that have large core counts and large page sizes, but limited
> > memory, the userfaultfd test hugepage requirement is too large.
> >
> > Exiting early due to missing one test's requirements is a rather aggressive
> > strategy, and prevents a lot of other tests from running. Remove the
> > early exit to prevent this.
> Why don't we only skip that particular test which requires huge number of
> pages instead? Thus the behavior of this script would remain same.
Hi Muhammad,

That would not solve the problem-- The issue is not with the
userfaultfd test, but rather this part of the script that tries to
allocate the hugepages. If it doesnt succeed at allocating the right
amount of hugepages it will exit the run_vmtests.sh script, thus
stopping all other tests. With the `exit` removed, the test suite is
able to run, and upon running the userfaultfd test will result in a
failed test case.

If you'd like I can follow up with a patch to skip the test cases (in
the actually test) rather than failing.

Cheers,
-- Nico
>
> >
> > Fixes: ee00479d6702 ("selftests: vm: Try harder to allocate huge pages")
> > Signed-off-by: Nico Pache <npache@...hat.com>
> > ---
> >  tools/testing/selftests/mm/run_vmtests.sh | 1 -
> >  1 file changed, 1 deletion(-)
> >
> > diff --git a/tools/testing/selftests/mm/run_vmtests.sh b/tools/testing/selftests/mm/run_vmtests.sh
> > index 246d53a5d7f28..727ea22ba408e 100755
> > --- a/tools/testing/selftests/mm/run_vmtests.sh
> > +++ b/tools/testing/selftests/mm/run_vmtests.sh
> > @@ -173,7 +173,6 @@ if [ -n "$freepgs" ] && [ -n "$hpgsize_KB" ]; then
> >       if [ "$freepgs" -lt "$needpgs" ]; then
> >               printf "Not enough huge pages available (%d < %d)\n" \
> >                      "$freepgs" "$needpgs"
> > -             exit 1
> >       fi
> >  else
> >       echo "no hugetlbfs support in kernel?"
>
> --
> BR,
> Muhammad Usama Anjum
>