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From:   Suren Baghdasaryan <surenb@google.com>
Date:   Mon, 30 Oct 2023 14:22:15 -0700
Message-ID: <CAJuCfpHzEn0=6-4sngq8qQ6h5mSM+Gj-4OqOGF=cvefouk1cbw@mail.gmail.com>
Subject: Re: [PATCH v4 5/5] selftests/mm: add UFFDIO_MOVE ioctl test
To:     Peter Xu <peterx@redhat.com>
Cc:     akpm@linux-foundation.org, viro@zeniv.linux.org.uk,
        brauner@kernel.org, shuah@kernel.org, aarcange@redhat.com,
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        kaleshsingh@google.com, ngeoffray@google.com, jdduke@google.com,
        linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
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On Mon, Oct 30, 2023 at 1:35=E2=80=AFPM Peter Xu <peterx@redhat.com> wrote:
>
> On Mon, Oct 30, 2023 at 01:22:02PM -0700, Suren Baghdasaryan wrote:
> > > > +static int adjust_page_size(void)
> > > > +{
> > > > +     page_size =3D default_huge_page_size();
> > >
> > > This is hacky too, currently page_size is the real page_size backing =
the
> > > memory.
> > >
> > > To make thp test simple, maybe just add one more test to MOVE a large=
 chunk
> > > to replace the thp test, which may contain a few thps?  It also doesn=
't
> > > need to be fault based.
> >
> > Sorry, I didn't get your suggestion. Could you please clarify? Which
> > thp test are you referring to?
>
> The new "move-pmd" test.
>
> I meant maybe it makes sense to have one separate MOVE test for when one
> ioctl(MOVE) covers a large range which can cover some thps.  Then that wi=
ll
> trigger thp paths.  Assuming the fault paths are already covered in the
> generic "move" test.

Oh, you mean I should not share uffd_move_test() between move and
move-pmd test and have separate logic instead that does not rely on
the page_size overrides? If so then I think that's doable. Some more
code but probably cleaner.

>
> Thanks,
>
> --
> Peter Xu
>