[-mm PATCH v2 00/25] get_user_pages() for dax pte and pmd mappings

[Dan Williams <dan.j.williams@intel.com>]

Changes since v1: [1]

1/ Rebase on latest -next (20151209).  Fixed up PHYSICAL_PAGE_MASK, but
   no other major collisions.

2/ Decreased the transfer size in "dax: increase granularity of
   dax_clear_blocks() operations" to get the max latency to reschedule
   under 1ms and average latency under 150us. (Andrew)

3/ Add cc's for x86 maintainers

4/ Add Tested-by: Logan Gunthorpe

This update, as before, passes the ndctl [2] and nvml [3] test suites.

[1]: https://lists.01.org/pipermail/linux-nvdimm/2015-December/003213.html
[2]: https://github.com/pmem/ndctl
[3]: https://github.com/pmem/nvml

A git tree of this set is available here:

  git://git.kernel.org/pub/scm/linux/kernel/git/djbw/nvdimm libnvdimm-pending

---

Summary:

To date, we have implemented two I/O usage models for persistent memory,
PMEM (a persistent "ram disk") and DAX (mmap persistent memory into
userspace).  This series adds a third, DAX-GUP, that allows DAX mappings
to be the target of direct-i/o.  It allows userspace to coordinate
DMA/RDMA from/to persistent memory.

The implementation leverages the ZONE_DEVICE mm-zone that went into
4.3-rc1 (also discussed at kernel summit) to flag pages that are owned
and dynamically mapped by a device driver.  The pmem driver, after
mapping a persistent memory range into the system memmap via
devm_memremap_pages(), arranges for DAX to distinguish pfn-only versus
page-backed pmem-pfns via flags in the new pfn_t type.

The DAX code, upon seeing a PFN_DEV+PFN_MAP flagged pfn, flags the
resulting pte(s) inserted into the process page tables with a new
_PAGE_DEVMAP flag.  Later, when get_user_pages() is walking ptes it keys
off _PAGE_DEVMAP to pin the device hosting the page range active.
Finally, get_page() and put_page() are modified to take references
against the device driver established page mapping.

Finally, this need for "struct page" for persistent memory requires
memory capacity to store the memmap array.  Given the memmap array for a
large pool of persistent may exhaust available DRAM introduce a
mechanism to allocate the memmap from persistent memory.  The new "struct
vmem_altmap *"  parameter to devm_memremap_pages() enables
arch_add_memory() to use reserved pmem capacity rather than the page
allocator.

---

Dan Williams (23):
      pmem, dax: clean up clear_pmem()
      dax: increase granularity of dax_clear_blocks() operations
      dax: guarantee page aligned results from bdev_direct_access()
      dax: fix lifetime of in-kernel dax mappings with dax_map_atomic()
      um: kill pfn_t
      kvm: rename pfn_t to kvm_pfn_t
      mm, dax, pmem: introduce pfn_t
      mm: introduce find_dev_pagemap()
      x86, mm: introduce vmem_altmap to augment vmemmap_populate()
      libnvdimm, pfn, pmem: allocate memmap array in persistent memory
      avr32: convert to asm-generic/memory_model.h
      hugetlb: fix compile error on tile
      frv: fix compiler warning from definition of __pmd()
      x86, mm: introduce _PAGE_DEVMAP
      mm, dax, gpu: convert vm_insert_mixed to pfn_t
      mm, dax: convert vmf_insert_pfn_pmd() to pfn_t
      list: introduce list_del_poison()
      libnvdimm, pmem: move request_queue allocation earlier in probe
      mm, dax, pmem: introduce {get|put}_dev_pagemap() for dax-gup
      mm, dax: dax-pmd vs thp-pmd vs hugetlbfs-pmd
      mm, x86: get_user_pages() for dax mappings
      dax: provide diagnostics for pmd mapping failures
      dax: re-enable dax pmd mappings

Ross Zwisler (1):
      mm, dax: fix livelock, allow dax pmd mappings to become writeable

Toshi Kani (1):
      dax: Split pmd map when fallback on COW


 arch/alpha/include/asm/pgtable.h        |    1 
 arch/arm/include/asm/kvm_mmu.h          |    5 -
 arch/arm/kvm/mmu.c                      |   10 +
 arch/arm64/include/asm/kvm_mmu.h        |    3 
 arch/avr32/include/asm/page.h           |    8 -
 arch/frv/include/asm/page.h             |    2 
 arch/ia64/include/asm/page.h            |    1 
 arch/ia64/include/asm/pgtable.h         |    1 
 arch/m68k/include/asm/page_mm.h         |    1 
 arch/m68k/include/asm/page_no.h         |    1 
 arch/mips/include/asm/kvm_host.h        |    6 -
 arch/mips/kvm/emulate.c                 |    2 
 arch/mips/kvm/tlb.c                     |   14 +
 arch/mn10300/include/asm/page.h         |    1 
 arch/parisc/include/asm/pgtable.h       |    1 
 arch/powerpc/include/asm/kvm_book3s.h   |    4 
 arch/powerpc/include/asm/kvm_ppc.h      |    2 
 arch/powerpc/include/asm/pgtable.h      |    1 
 arch/powerpc/kvm/book3s.c               |    6 -
 arch/powerpc/kvm/book3s_32_mmu_host.c   |    2 
 arch/powerpc/kvm/book3s_64_mmu_host.c   |    2 
 arch/powerpc/kvm/e500.h                 |    2 
 arch/powerpc/kvm/e500_mmu_host.c        |    8 -
 arch/powerpc/kvm/trace_pr.h             |    2 
 arch/powerpc/sysdev/axonram.c           |    8 -
 arch/sh/include/asm/pgtable-3level.h    |    1 
 arch/sparc/include/asm/pgtable_64.h     |    2 
 arch/tile/include/asm/pgtable.h         |    1 
 arch/um/include/asm/page.h              |    7 -
 arch/um/include/asm/pgtable-3level.h    |    5 -
 arch/um/include/asm/pgtable.h           |    2 
 arch/x86/include/asm/pgtable.h          |   26 +++
 arch/x86/include/asm/pgtable_types.h    |    7 +
 arch/x86/include/asm/pmem.h             |    7 -
 arch/x86/kvm/iommu.c                    |   11 +
 arch/x86/kvm/mmu.c                      |   37 ++--
 arch/x86/kvm/mmu_audit.c                |    2 
 arch/x86/kvm/paging_tmpl.h              |    6 -
 arch/x86/kvm/vmx.c                      |    2 
 arch/x86/kvm/x86.c                      |    2 
 arch/x86/mm/gup.c                       |   56 +++++-
 arch/x86/mm/init_64.c                   |   32 +++
 arch/x86/mm/pat.c                       |    4 
 drivers/block/brd.c                     |    4 
 drivers/gpu/drm/exynos/exynos_drm_gem.c |    3 
 drivers/gpu/drm/gma500/framebuffer.c    |    3 
 drivers/gpu/drm/msm/msm_gem.c           |    3 
 drivers/gpu/drm/omapdrm/omap_gem.c      |    6 -
 drivers/gpu/drm/ttm/ttm_bo_vm.c         |    3 
 drivers/nvdimm/pfn_devs.c               |    3 
 drivers/nvdimm/pmem.c                   |   70 +++++--
 drivers/s390/block/dcssblk.c            |   10 -
 fs/Kconfig                              |    3 
 fs/block_dev.c                          |   15 +-
 fs/dax.c                                |  290 +++++++++++++++++++----------
 include/asm-generic/pgtable.h           |   10 +
 include/linux/blkdev.h                  |   19 ++
 include/linux/huge_mm.h                 |   15 +-
 include/linux/hugetlb.h                 |    1 
 include/linux/io.h                      |   15 --
 include/linux/kvm_host.h                |   37 ++--
 include/linux/kvm_types.h               |    2 
 include/linux/list.h                    |   17 ++
 include/linux/memory_hotplug.h          |    3 
 include/linux/mm.h                      |  310 ++++++++++++++++++++++++++++++-
 include/linux/mm_types.h                |    5 +
 include/linux/pfn.h                     |    9 +
 kernel/memremap.c                       |  188 ++++++++++++++++++-
 lib/list_debug.c                        |    4 
 mm/gup.c                                |   18 ++
 mm/huge_memory.c                        |  131 +++++++++----
 mm/memory.c                             |   25 +--
 mm/memory_hotplug.c                     |   66 +++++--
 mm/mprotect.c                           |    5 -
 mm/page_alloc.c                         |   10 +
 mm/pgtable-generic.c                    |    2 
 mm/sparse-vmemmap.c                     |   37 ++++
 mm/sparse.c                             |    8 +
 mm/swap.c                               |   15 ++
 virt/kvm/kvm_main.c                     |   47 ++---
 80 files changed, 1300 insertions(+), 416 deletions(-)

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