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From:   Lokesh Gidra <lokeshgidra@google.com>
Date:   Wed, 4 Oct 2023 00:39:28 +0100
Message-ID: <CA+EESO5UPJrWpUKLg6m=1EmG6P9oXW6ADRkbRKjijVxj641qFQ@mail.gmail.com>
Subject: Re: [PATCH v2 2/3] userfaultfd: UFFDIO_REMAP uABI
To:     Suren Baghdasaryan <surenb@google.com>
Cc:     Peter Xu <peterx@redhat.com>, David Hildenbrand <david@redhat.com>,
        Jann Horn <jannh@google.com>, akpm@linux-foundation.org,
        viro@zeniv.linux.org.uk, brauner@kernel.org, shuah@kernel.org,
        aarcange@redhat.com, hughd@google.com, mhocko@suse.com,
        axelrasmussen@google.com, rppt@kernel.org, willy@infradead.org,
        Liam.Howlett@oracle.com, zhangpeng362@huawei.com,
        bgeffon@google.com, 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, kernel-team@android.com
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On Tue, Oct 3, 2023 at 11:26=E2=80=AFPM Suren Baghdasaryan <surenb@google.c=
om> wrote:
>
> On Tue, Oct 3, 2023 at 2:21=E2=80=AFPM Peter Xu <peterx@redhat.com> wrote=
:
> >
> > On Tue, Oct 03, 2023 at 11:08:07PM +0200, David Hildenbrand wrote:
> > > Sorry I have to ask: has this ever been discussed on the list? I don'=
t see
> > > any pointers. If not, then probably the number of people that know ab=
out the
> > > history can be counted with my two hands and that shouldn't be the ba=
sis for
> > > making decisions.
> >
> > For example:
> >
> > https://lore.kernel.org/all/1425575884-2574-21-git-send-email-aarcange@=
redhat.com/
>
> There was another submission in 2019:
> https://lore.kernel.org/all/cover.1547251023.git.blake.caldwell@colorado.=
edu/
>
> Though both times it did not generate much discussion. I don't have a
> strong preference though MOVE sounds more generic to me TBH (it
> specifies the operation rather than REMAP which hints on how that
> operation is carried out). But again, I'm fine either way.

That's a good point. IMHO, if in future we want to have the fallback
implemented, then MOVE would be a more appropriate name than REMAP.

> As for UFFDIO_MOVE_ZERO_COPY_ONLY vs UFFDIO_MOVE_MODE_ALLOW_COPY, I
> find it weird that the default (the most efficient/desired) mode of
> operation needs a flag. I would prefer to have no flag initially and
> add UFFDIO_MOVE_MODE_ALLOW_COPY or whatever name is more appropriate
> when/if we ever need it. Makes sense?

Agreed!
>
> >
> > --
> > Peter Xu
> >
> > --
> > To unsubscribe from this group and stop receiving emails from it, send =
an email to kernel-team+unsubscribe@android.com.
> >