[HMM v14 00/16] HMM (Heterogeneous Memory Management) v14

[JÃrÃme Glisse]

Cliff note: HMM offers 2 things (each standing on its own). First
it allows to use device memory transparently inside any process
without any modifications to process program code. Second it allows
to mirror process address space on a device.

Change since v13 are small, it was about including everyone remarks
into the patchset (splitting each features into its own kernel config,
adding better comment, splitting optimization from base implementation,
improved comments, ...).


Patchset is divided into 3 features that can each be use independently
from one another. First is changes to ZONE_DEVICE so we can have struct
page for device un-addressable memory (patch 2-6). Second is process
address space mirroring (patch 8 to 10), this allow to snapshot CPU
page table and to keep the device page table synchronize with the CPU
one.

Last is a new page migration helper which allow migration for range of
virtual address using hardware copy engine (patch 11-14).

Other patches just introduce common definitions or add safety net to
catch wrong use of some of the features.


Andrew do you want anyone specific to review any specific part of the
patchset before considering it for inclusion ? At this point i want
to know if there is ever a chance of getting this upstream or do we
decide that we don't want to support this kind of hardware ?


In this patchset i restricted myself to set of core features what
is missing:
  - force read only on CPU for memory duplication and GPU atomic
  - changes to mmu_notifier for optimization purposes
  - migration of file back page to device memory

I plan to submit a couple more patchset to implement those features
once core HMM is upstream.


Previous patchset posting :
    v1 http://lwn.net/Articles/597289/
    v2 https://lkml.org/lkml/2014/6/12/559
    v3 https://lkml.org/lkml/2014/6/13/633
    v4 https://lkml.org/lkml/2014/8/29/423
    v5 https://lkml.org/lkml/2014/11/3/759
    v6 http://lwn.net/Articles/619737/
    v7 http://lwn.net/Articles/627316/
    v8 https://lwn.net/Articles/645515/
    v9 https://lwn.net/Articles/651553/
    v10 https://lwn.net/Articles/654430/
    v11 http://www.gossamer-threads.com/lists/linux/kernel/2286424
    v12 http://www.kernelhub.org/?msg=972982&p=2
    v13 https://lwn.net/Articles/706856/

Cheers,
JÃrÃme

JÃrÃme Glisse (16):
  mm/free_hot_cold_page: catch ZONE_DEVICE pages
  mm/memory/hotplug: convert device bool to int to allow for more flags
    v2
  mm/ZONE_DEVICE/devmem_pages_remove: allow early removal of device
    memory
  mm/ZONE_DEVICE/free-page: callback when page is freed
  mm/ZONE_DEVICE/unaddressable: add support for un-addressable device
    memory
  mm/ZONE_DEVICE/x86: add support for un-addressable device memory
  mm/hmm: heterogeneous memory management (HMM for short)
  mm/hmm/mirror: mirror process address space on device with HMM helpers
  mm/hmm/mirror: helper to snapshot CPU page table
  mm/hmm/mirror: device page fault handler
  mm/hmm/migrate: support un-addressable ZONE_DEVICE page in migration
  mm/hmm/migrate: add new boolean copy flag to migratepage() callback
  mm/hmm/migrate: new memory migration helper for use with device memory
    v2
  mm/hmm/migrate: optimize page map once in vma being migrated
  mm/hmm/devmem: device driver helper to hotplug ZONE_DEVICE memory
  mm/hmm/devmem: dummy HMM device as an helper for ZONE_DEVICE memory

 MAINTAINERS                                |    7 +
 arch/ia64/mm/init.c                        |   23 +-
 arch/powerpc/mm/mem.c                      |   22 +-
 arch/s390/mm/init.c                        |   10 +-
 arch/sh/mm/init.c                          |   22 +-
 arch/tile/mm/init.c                        |   10 +-
 arch/x86/mm/init_32.c                      |   23 +-
 arch/x86/mm/init_64.c                      |   41 +-
 drivers/dax/pmem.c                         |    3 +-
 drivers/nvdimm/pmem.c                      |    7 +-
 drivers/staging/lustre/lustre/llite/rw26.c |    8 +-
 fs/aio.c                                   |    7 +-
 fs/btrfs/disk-io.c                         |   11 +-
 fs/hugetlbfs/inode.c                       |    9 +-
 fs/nfs/internal.h                          |    5 +-
 fs/nfs/write.c                             |    9 +-
 fs/proc/task_mmu.c                         |   10 +-
 fs/ubifs/file.c                            |    8 +-
 include/linux/balloon_compaction.h         |    3 +-
 include/linux/fs.h                         |   13 +-
 include/linux/hmm.h                        |  525 ++++++++++++++
 include/linux/memory_hotplug.h             |   31 +-
 include/linux/memremap.h                   |   60 +-
 include/linux/migrate.h                    |    7 +-
 include/linux/mm_types.h                   |    5 +
 include/linux/swap.h                       |   18 +-
 include/linux/swapops.h                    |   67 ++
 kernel/fork.c                              |    2 +
 kernel/memremap.c                          |   69 +-
 mm/Kconfig                                 |   51 ++
 mm/Makefile                                |    1 +
 mm/balloon_compaction.c                    |    2 +-
 mm/hmm.c                                   | 1082 ++++++++++++++++++++++++++++
 mm/memory.c                                |   62 ++
 mm/memory_hotplug.c                        |    4 +-
 mm/migrate.c                               |  687 +++++++++++++++++-
 mm/mprotect.c                              |   12 +
 mm/page_alloc.c                            |   10 +
 mm/rmap.c                                  |   47 ++
 mm/zsmalloc.c                              |   12 +-
 tools/testing/nvdimm/test/iomap.c          |    3 +-
 41 files changed, 2924 insertions(+), 84 deletions(-)
 create mode 100644 include/linux/hmm.h
 create mode 100644 mm/hmm.c

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2.4.3