[PATCH v4 0/9] mmu notifier provide context informations

[jglisse at redhat.com]

From: Jérôme Glisse <jglisse at redhat.com>

Hi Andrew, i see that you still have my event patch in you queue [1].
This patchset replace that single patch and is broken down in further
step so that it is easier to review and ascertain that no mistake were
made during mechanical changes. Here are the step:

    Patch 1 - add the enum values
    Patch 2 - coccinelle semantic patch to convert all call site of
              mmu_notifier_range_init to default enum value and also
              to passing down the vma when it is available
    Patch 3 - update many call site to more accurate enum values
    Patch 4 - add the information to the mmu_notifier_range struct
    Patch 5 - helper to test if a range is updated to read only

All the remaining patches are update to various driver to demonstrate
how this new information get use by device driver. I build tested
with make all and make all minus everything that enable mmu notifier
ie building with MMU_NOTIFIER=no. Also tested with some radeon,amd
gpu and intel gpu.

If they are no objections i believe best plan would be to merge the
the first 5 patches (all mm changes) through your queue for 5.1 and
then to delay driver update to each individual driver tree for 5.2.
This will allow each individual device driver maintainer time to more
thouroughly test this more then my own testing.

Note that i also intend to use this feature further in nouveau and
HMM down the road. I also expect that other user like KVM might be
interested into leveraging this new information to optimize some of
there secondary page table invalidation.

Here is an explaination on the rational for this patchset:


CPU page table update can happens for many reasons, not only as a result
of a syscall (munmap(), mprotect(), mremap(), madvise(), ...) but also
as a result of kernel activities (memory compression, reclaim, migration,
...).

This patch introduce a set of enums that can be associated with each of
the events triggering a mmu notifier. Latter patches take advantages of
those enum values.

- UNMAP: munmap() or mremap()
- CLEAR: page table is cleared (migration, compaction, reclaim, ...)
- PROTECTION_VMA: change in access protections for the range
- PROTECTION_PAGE: change in access protections for page in the range
- SOFT_DIRTY: soft dirtyness tracking

Being able to identify munmap() and mremap() from other reasons why the
page table is cleared is important to allow user of mmu notifier to
update their own internal tracking structure accordingly (on munmap or
mremap it is not longer needed to track range of virtual address as it
becomes invalid).

[1] https://www.ozlabs.org/~akpm/mmotm/broken-out/mm-mmu_notifier-contextual-information-for-event-triggering-invalidation-v2.patch

Cc: Christian König <christian.koenig at amd.com>
Cc: Jan Kara <jack at suse.cz>
Cc: Felix Kuehling <Felix.Kuehling at amd.com>
Cc: Jason Gunthorpe <jgg at mellanox.com>
Cc: Andrew Morton <akpm at linux-foundation.org>
Cc: Matthew Wilcox <mawilcox at microsoft.com>
Cc: Ross Zwisler <zwisler at kernel.org>
Cc: Dan Williams <dan.j.williams at intel.com>
Cc: Paolo Bonzini <pbonzini at redhat.com>
Cc: Radim Krčmář <rkrcmar at redhat.com>
Cc: Michal Hocko <mhocko at kernel.org>
Cc: Ralph Campbell <rcampbell at nvidia.com>
Cc: John Hubbard <jhubbard at nvidia.com>
Cc: kvm at vger.kernel.org
Cc: dri-devel at lists.freedesktop.org
Cc: linux-rdma at vger.kernel.org
Cc: linux-fsdevel at vger.kernel.org
Cc: Arnd Bergmann <arnd at arndb.de>

Jérôme Glisse (9):
  mm/mmu_notifier: contextual information for event enums
  mm/mmu_notifier: contextual information for event triggering
    invalidation
  mm/mmu_notifier: use correct mmu_notifier events for each invalidation
  mm/mmu_notifier: pass down vma and reasons why mmu notifier is
    happening
  mm/mmu_notifier: mmu_notifier_range_update_to_read_only() helper
  gpu/drm/radeon: optimize out the case when a range is updated to read
    only
  gpu/drm/amdgpu: optimize out the case when a range is updated to read
    only
  gpu/drm/i915: optimize out the case when a range is updated to read
    only
  RDMA/umem_odp: optimize out the case when a range is updated to read
    only

 drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c  | 13 ++++++++
 drivers/gpu/drm/i915/i915_gem_userptr.c | 16 ++++++++++
 drivers/gpu/drm/radeon/radeon_mn.c      | 13 ++++++++
 drivers/infiniband/core/umem_odp.c      | 22 +++++++++++--
 fs/proc/task_mmu.c                      |  3 +-
 include/linux/mmu_notifier.h            | 42 ++++++++++++++++++++++++-
 include/rdma/ib_umem_odp.h              |  1 +
 kernel/events/uprobes.c                 |  3 +-
 mm/huge_memory.c                        | 14 +++++----
 mm/hugetlb.c                            | 11 ++++---
 mm/khugepaged.c                         |  3 +-
 mm/ksm.c                                |  6 ++--
 mm/madvise.c                            |  3 +-
 mm/memory.c                             | 25 +++++++++------
 mm/migrate.c                            |  5 ++-
 mm/mmu_notifier.c                       | 10 ++++++
 mm/mprotect.c                           |  4 ++-
 mm/mremap.c                             |  3 +-
 mm/oom_kill.c                           |  3 +-
 mm/rmap.c                               |  6 ++--
 20 files changed, 171 insertions(+), 35 deletions(-)

-- 
2.17.2