[PATCH 0/7] userfaultfd: add support for shared memory

From: Mike Rapoport
Date: Thu Aug 04 2016 - 07:46:20 EST


These patches enable userfaultfd support for shared memory mappings. The
VMAs backed with shmem/tmpfs can be registered with userfaultfd which
allows management of page faults in these areas by userland.

This patch set adds implementation of shmem_mcopy_atomic_pte for proper
handling of UFFDIO_COPY command. A callback to handle_userfault is added
to shmem page fault handling path. The userfaultfd register/unregister
methods are extended to allow shmem VMAs.

The UFFDIO_ZEROPAGE and UFFDIO_REGISTER_MODE_WP are not implemented which
is reflected by userfaultfd API handshake methods.

The patches are based on current Andrea's tree:
https://git.kernel.org/pub/scm/linux/kernel/git/andrea/aa.git

Mike Rapoport (7):
userfaultfd: introduce vma_can_userfault
userfaultfd: shmem: add shmem_mcopy_atomic_pte for userfaultfd support
userfaultfd: shmem: introduce vma_is_shmem
userfaultfd: shmem: use shmem_mcopy_atomic_pte for shared memory
userfaultfd: shmem: add userfaultfd hook for shared memory faults
userfaultfd: shmem: allow registration of shared memory ranges
userfaultfd: shmem: add userfaultfd_shmem test

fs/userfaultfd.c | 32 ++++---
include/linux/mm.h | 10 +++
include/linux/shmem_fs.h | 11 +++
include/uapi/linux/userfaultfd.h | 2 +-
mm/shmem.c | 139 +++++++++++++++++++++++++++++--
mm/userfaultfd.c | 31 ++++---
tools/testing/selftests/vm/Makefile | 3 +
tools/testing/selftests/vm/run_vmtests | 11 +++
tools/testing/selftests/vm/userfaultfd.c | 39 ++++++++-
9 files changed, 237 insertions(+), 41 deletions(-)

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1.9.1