On Thu, Feb 4, 2021 at 11:57 AM Randy Dunlap <rdunlap@xxxxxxxxxxxxx> wrote: > > Hi Axel- > > one typo found: > > On 2/4/21 10:34 AM, Axel Rasmussen wrote: > > Reword / reorganize things a little bit into "lists", so new features / > > modes / ioctls can sort of just be appended. > > Good plan. > > > > > Signed-off-by: Axel Rasmussen <axelrasmussen@xxxxxxxxxx> > > --- > > Documentation/admin-guide/mm/userfaultfd.rst | 107 ++++++++++++------- > > 1 file changed, 66 insertions(+), 41 deletions(-) > > > > diff --git a/Documentation/admin-guide/mm/userfaultfd.rst b/Documentation/admin-guide/mm/userfaultfd.rst > > index 65eefa66c0ba..cfd3daf59d0e 100644 > > --- a/Documentation/admin-guide/mm/userfaultfd.rst > > +++ b/Documentation/admin-guide/mm/userfaultfd.rst > > [snip] > > > - > > -Once the ``userfaultfd`` has been enabled the ``UFFDIO_REGISTER`` ioctl should > > -be invoked (if present in the returned ``uffdio_api.ioctls`` bitmask) to > > -register a memory range in the ``userfaultfd`` by setting the > > +events, except page fault notifications, may be generated: > > + > > +- The ``UFFD_FEATURE_EVENT_*`` flags indicate that various other events > > + other than page faults are supported. These events are described in more > > + detail below in the `Non-cooperative userfaultfd`_ section. > > + > > +- ``UFFD_FEATURE_MISSING_HUGETLBFS`` and ``UFFD_FEATURE_MISSING_SHMEM`` > > + indicate that the kernel supports ``UFFDIO_REGISTER_MODE_MISSING`` > > + registrations for hugetlbfs and shared memory (covering all shmem APIs, > > + i.e. tmpfs, ``IPCSHM``, ``/dev/zero``, ``MAP_SHARED``, ``memfd_create``, > > + etc) virtual memory areas, respectively. > > + > > +- ``UFFD_FEATURE_MINOR_HUGETLBFS`` indicates that the kernel supports > > + ``UFFDIO_REGISTER_MODE_MINOR`` registration for hugetlbfs virtual memory > > + areas. > > + > > +The userland application should set the feature flags it intends to use > > (ah, userspace has moved to userland temporarily. :) For better or worse, other parts of the document I'm not touching also use this wording. Maybe we should s/userland/userspace/g, but perhaps better done as a separate commit to keep this diff focused? Anecdotally, the use of "userland" doesn't seem to be completely unprecedented (e.g. grep -r "userland" | wc -l yields 566 matches in the kernel tree). I don't have strong feelings, and I was amused by picturing some Shire-esque countryside with a friendly sign that reads: ~userland welcomes you~. :) > > > +when envoking the ``UFFDIO_API`` ioctl, to request that those features be > > invoking Whoops! Will send a new version with this fix. Thanks! > > > +enabled if supported. > > > thanks. > -- > ~Randy >
