From: Axel Rasmussen <axelrasmussen@google.com>
To: Peter Xu <peterx@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Andrea Arcangeli <aarcange@redhat.com>,
Hugh Dickins <hughd@google.com>,
Jerome Glisse <jglisse@redhat.com>, Joe Perches <joe@perches.com>,
Lokesh Gidra <lokeshgidra@google.com>,
Mike Kravetz <mike.kravetz@oracle.com>,
Mike Rapoport <rppt@linux.vnet.ibm.com>, Shaohua Li <shli@fb.com>,
Shuah Khan <shuah@kernel.org>,
Stephen Rothwell <sfr@canb.auug.org.au>,
Wang Qing <wangqing@vivo.com>,
linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org,
LKML <linux-kernel@vger.kernel.org>,
linux-kselftest@vger.kernel.org, Linux MM <linux-mm@kvack.org>,
Brian Geffon <bgeffon@google.com>,
"Dr . David Alan Gilbert" <dgilbert@redhat.com>,
Mina Almasry <almasrymina@google.com>,
Oliver Upton <oupton@google.com>
Subject: Re: [PATCH v5 09/10] userfaultfd/selftests: reinitialize test context in each test
Date: Tue, 18 May 2021 15:28:52 -0700 [thread overview]
Message-ID: <CAJHvVch3SZ80yt+FnK5M=m4haJ-pFZqvMtGVYHnw9rs1pBkNcw@mail.gmail.com> (raw)
In-Reply-To: <YKQqKrl+/cQ1utrb@t490s>
I suppose it will be squashed anyway, but in case it's useful feel free to add:
Reviewed-by: Axel Rasmussen <axelrasmussen@google.com>
Thanks for catching this, Peter!
On Tue, May 18, 2021 at 1:57 PM Peter Xu <peterx@redhat.com> wrote:
>
> On Tue, Apr 27, 2021 at 03:52:43PM -0700, Axel Rasmussen wrote:
> > Currently, the context (fds, mmap-ed areas, etc.) are global. Each test
> > mutates this state in some way, in some cases really "clobbering it"
> > (e.g., the events test mremap-ing area_dst over the top of area_src, or
> > the minor faults tests overwriting the count_verify values in the test
> > areas). We run the tests in a particular order, each test is careful to
> > make the right assumptions about its starting state, etc.
> >
> > But, this is fragile. It's better for a test's success or failure to not
> > depend on what some other prior test case did to the global state.
> >
> > To that end, clear and reinitialize the test context at the start of
> > each test case, so whatever prior test cases did doesn't affect future
> > tests.
> >
> > This is particularly relevant to this series because the events test's
> > mremap of area_dst screws up assumptions the minor fault test was
> > relying on. This wasn't a problem for hugetlb, as we don't mremap in
> > that case.
> >
> > Signed-off-by: Axel Rasmussen <axelrasmussen@google.com>
>
> Hi, Andrew,
>
> There's a conflict on the uffd test case with v5.13-rc1-mmots-2021-05-13-17-23
> between this patch and the uffd pagemap series, so I think we may need to queue
> another fixup patch (to be squashed into this patch of Axel's) which is
> attached.
>
> Thanks,
>
> --
> Peter Xu
next prev parent reply other threads:[~2021-05-18 22:29 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-27 22:52 [PATCH v5 00/10] userfaultfd: add minor fault handling for shmem Axel Rasmussen
2021-04-27 22:52 ` [PATCH v5 01/10] userfaultfd/hugetlbfs: avoid including userfaultfd_k.h in hugetlb.h Axel Rasmussen
2021-04-27 22:52 ` [PATCH v5 02/10] userfaultfd/shmem: combine shmem_{mcopy_atomic,mfill_zeropage}_pte Axel Rasmussen
2021-04-27 22:52 ` [PATCH v5 03/10] userfaultfd/shmem: support minor fault registration for shmem Axel Rasmussen
2021-04-28 0:02 ` Hugh Dickins
2021-04-27 22:52 ` [PATCH v5 04/10] userfaultfd/shmem: support UFFDIO_CONTINUE " Axel Rasmussen
2021-04-28 0:03 ` Hugh Dickins
2021-04-28 15:10 ` Peter Xu
2021-04-27 22:52 ` [PATCH v5 05/10] userfaultfd/shmem: advertise shmem minor fault support Axel Rasmussen
2021-04-28 0:04 ` Hugh Dickins
2021-04-28 15:11 ` Peter Xu
2021-04-27 22:52 ` [PATCH v5 06/10] userfaultfd/shmem: modify shmem_mcopy_atomic_pte to use install_pte() Axel Rasmussen
2021-04-28 0:58 ` Hugh Dickins
2021-04-28 15:56 ` Peter Xu
2021-04-28 15:59 ` Axel Rasmussen
2021-04-28 16:23 ` Peter Xu
2021-04-27 22:52 ` [PATCH v5 07/10] userfaultfd/selftests: use memfd_create for shmem test type Axel Rasmussen
2021-04-27 22:52 ` [PATCH v5 08/10] userfaultfd/selftests: create alias mappings in the shmem test Axel Rasmussen
2021-04-27 22:52 ` [PATCH v5 09/10] userfaultfd/selftests: reinitialize test context in each test Axel Rasmussen
2021-04-28 17:23 ` Peter Xu
2021-05-18 20:57 ` Peter Xu
2021-05-18 22:28 ` Axel Rasmussen [this message]
2021-04-27 22:52 ` [PATCH v5 10/10] userfaultfd/selftests: exercise minor fault handling shmem support Axel Rasmussen
2021-04-28 17:26 ` Peter Xu
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