[PATCH 0/3] mmu notifier contextual informations

[jglisse at redhat.com]

From: Jérôme Glisse <jglisse at redhat.com>

This patchset add contextual information, why an invalidation is
happening, to mmu notifier callback. This is necessary for user
of mmu notifier that wish to maintains their own data structure
without having to add new fields to struct vm_area_struct (vma).

For instance device can have they own page table that mirror the
process address space. When a vma is unmap (munmap() syscall) the
device driver can free the device page table for the range.

Today we do not have any information on why a mmu notifier call
back is happening and thus device driver have to assume that it
is always an munmap(). This is inefficient at it means that it
needs to re-allocate device page table on next page fault and
rebuild the whole device driver data structure for the range.

Other use case beside munmap() also exist, for instance it is
pointless for device driver to invalidate the device page table
when the invalidation is for the soft dirtyness tracking. Or
device driver can optimize away mprotect() that change the page
table permission access for the range.

This patchset enable all this optimizations for device driver.
I do not include any of those in this serie but other patchset
i am posting will leverage this.


>From code point of view the patchset is pretty simple, the first
two patches consolidate all mmu notifier arguments into a struct
so that it is easier to add/change arguments. The last patch adds
the contextual information (munmap, protection, soft dirty, clear,
...).

Cheers,
Jérôme

Cc: Andrew Morton <akpm at linux-foundation.org>
Cc: Matthew Wilcox <mawilcox at microsoft.com>
Cc: Ross Zwisler <zwisler at kernel.org>
Cc: Jan Kara <jack at suse.cz>
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: Christian Koenig <christian.koenig at amd.com>
Cc: Felix Kuehling <felix.kuehling at amd.com>
Cc: Ralph Campbell <rcampbell at nvidia.com>
Cc: John Hubbard <jhubbard at nvidia.com>
Cc: kvm at vger.kernel.org
Cc: linux-rdma at vger.kernel.org
Cc: linux-fsdevel at vger.kernel.org
Cc: dri-devel at lists.freedesktop.org

Jérôme Glisse (3):
  mm/mmu_notifier: use structure for invalidate_range_start/end callback
  mm/mmu_notifier: use structure for invalidate_range_start/end calls
  mm/mmu_notifier: contextual information for event triggering
    invalidation

 drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c  |  43 ++++-----
 drivers/gpu/drm/i915/i915_gem_userptr.c |  14 ++-
 drivers/gpu/drm/radeon/radeon_mn.c      |  16 ++--
 drivers/infiniband/core/umem_odp.c      |  20 ++---
 drivers/infiniband/hw/hfi1/mmu_rb.c     |  13 ++-
 drivers/misc/mic/scif/scif_dma.c        |  11 +--
 drivers/misc/sgi-gru/grutlbpurge.c      |  14 ++-
 drivers/xen/gntdev.c                    |  12 +--
 fs/dax.c                                |  11 ++-
 fs/proc/task_mmu.c                      |  10 ++-
 include/linux/mm.h                      |   4 +-
 include/linux/mmu_notifier.h            | 106 +++++++++++++++-------
 kernel/events/uprobes.c                 |  13 +--
 mm/hmm.c                                |  23 ++---
 mm/huge_memory.c                        |  58 ++++++------
 mm/hugetlb.c                            |  63 +++++++------
 mm/khugepaged.c                         |  13 +--
 mm/ksm.c                                |  26 +++---
 mm/madvise.c                            |  22 ++---
 mm/memory.c                             | 112 ++++++++++++++----------
 mm/migrate.c                            |  30 ++++---
 mm/mmu_notifier.c                       |  22 +++--
 mm/mprotect.c                           |  17 ++--
 mm/mremap.c                             |  14 +--
 mm/oom_kill.c                           |  20 +++--
 mm/rmap.c                               |  34 ++++---
 virt/kvm/kvm_main.c                     |  14 ++-
 27 files changed, 421 insertions(+), 334 deletions(-)

-- 
2.17.2