Ah yes, I should have modified the commit message when I swapped them
the first time - sorry for overlooking it.

As I said in the other thread, unless someone strongly objects I'll
just re-order them the other way around, minor faults first and then
CONTINUE, which resolves this concern at least.

I'm not too worried about leaving them split. Clearly we'll never
release a kernel with one but not the other. So the only scenario I
can imagine is, bisecting. But, bisecting across the range where UFFD
shmem minor faults were introduced, if you're using that feature,
won't really work out well no matter what we do. If you aren't using
this feature explicitly, then any of the configurations we've talked
about are fine.

On Tue, Apr 27, 2021 at 8:57 AM Peter Xu [off-list ref] wrote:

On Mon, Apr 26, 2021 at 07:23:57PM -0700, Hugh Dickins wrote:

quoted

On Tue, 20 Apr 2021, Axel Rasmussen wrote:

quoted

This patch allows shmem-backed VMAs to be registered for minor faults.
Minor faults are appropriately relayed to userspace in the fault path,
for VMAs with the relevant flag.

This commit doesn't hook up the UFFDIO_CONTINUE ioctl for shmem-backed
minor faults, though, so userspace doesn't yet have a way to resolve
such faults.

Acked-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Axel Rasmussen <axelrasmussen@google.com>

And if this "04/10" had been numbered 03/10, I would have said
Acked-by: Hugh Dickins <hughd@google.com>

Just read the comment above: "so userspace doesn't yet have a way to
resolve such faults" - if it doesn't by this stage, we're in trouble.

Right, so merging the two patches might be easier.  Even if we don't merge
them, we'll need to touch up the commit message since at least above paragraph
is not true anymore as we've already have UFFDIO_CONTINUE.  Thanks,

--
Peter Xu