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From:   Suren Baghdasaryan <surenb@google.com>
Date:   Mon, 16 May 2022 12:55:55 -0700
Message-ID: <CAJuCfpE8p6KVqMorFKYmH7+sd+YBt37J2A10_K=CfG73KJUw_Q@mail.gmail.com>
Subject: Re: [PATCH v2 1/1] selftests: vm: add process_mrelease tests
To:     Andrew Morton <akpm@linux-foundation.org>
Cc:     Michal Hocko <mhocko@suse.com>,
        David Rientjes <rientjes@google.com>,
        Matthew Wilcox <willy@infradead.org>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Roman Gushchin <guro@fb.com>, Minchan Kim <minchan@kernel.org>,
        "Kirill A. Shutemov" <kirill@shutemov.name>,
        Andrea Arcangeli <aarcange@redhat.com>,
        Christian Brauner <brauner@kernel.org>,
        Christoph Hellwig <hch@infradead.org>,
        Oleg Nesterov <oleg@redhat.com>,
        David Hildenbrand <david@redhat.com>,
        Jann Horn <jannh@google.com>,
        Shakeel Butt <shakeelb@google.com>,
        Peter Xu <peterx@redhat.com>,
        John Hubbard <jhubbard@nvidia.com>, shuah@kernel.org,
        LKML <linux-kernel@vger.kernel.org>,
        linux-mm <linux-mm@kvack.org>, linux-kselftest@vger.kernel.org,
        kernel-team <kernel-team@android.com>
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On Mon, May 16, 2022 at 12:50 PM Andrew Morton
<akpm@linux-foundation.org> wrote:
>
> On Mon, 16 May 2022 00:55:38 -0700 Suren Baghdasaryan <surenb@google.com> wrote:
>
> > Introduce process_mrelease syscall sanity tests which include tests
> > which expect to fail:
> > - process_mrelease with invalid pidfd and flags inputs
> > - process_mrelease on a live process with no pending signals
> > and valid process_mrelease usage which is expected to succeed.
> > Because process_mrelease has to be used against a process with a pending
> > SIGKILL, it's possible that the process exits before process_mrelease
> > gets called. In such cases we retry the test with a victim that allocates
> > twice more memory up to 1GB. This would require the victim process to
> > spend more time during exit and process_mrelease has a better chance of
> > catching the process before it exits and succeeding.
> >
> > On success the test reports the amount of memory the child had to
> > allocate for reaping to succeed. Sample output:
> >     Success reaping a child with 1MB of memory allocations
> >
> > On failure the test reports the failure. Sample outputs:
> >     All process_mrelease attempts failed!
> >     process_mrelease: Invalid argument
> >
> > ...
> >
> > --- a/tools/testing/selftests/vm/run_vmtests.sh
> > +++ b/tools/testing/selftests/vm/run_vmtests.sh
> > @@ -287,6 +287,22 @@ else
> >       echo "[PASS]"
> >  fi
> >
> > +echo "---------------------"
> > +echo "running mrelease_test"
> > +echo "---------------------"
> > +./mrelease_test
> > +ret_val=$?
> > +
> > +if [ $ret_val -eq 0 ]; then
> > +     echo "[PASS]"
> > +elif [ $ret_val -eq $ksft_skip ]; then
> > +      echo "[SKIP]"
> > +      exitcode=$ksft_skip
> > +else
> > +     echo "[FAIL]"
> > +     exitcode=1
> > +fi
> > +
> >  echo "-------------------"
> >  echo "running mremap_test"
> >  echo "-------------------"
>
> Can you please redo this against
> git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm branch mm-stable
> or mm-unstable.  Or against linux-next?
>
> This script now has a helper function run_test which I think can be
> used here.

Ah, thanks for the note! I'll give it a couple days for more reviews
and the will post it over mmotm.