Re: [PATCH v2 2/3] userfaultfd: UFFDIO_REMAP uABI

Suren Baghdasaryan
2023-10-03T22:26:35Z

On Tue, Oct 3, 2023 at 2:21 PM 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 about the
> > history can be counted with my two hands and that shouldn't be the basis 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.
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?

>
> --
> Peter Xu
>
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