[PATCH v1 00/11] mm: page migration enhancement for thp

[Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>]

Hi everyone,

This patchset enhances page migration functionality to handle thp migration
for various page migration's callers:
 - mbind(2)
 - move_pages(2)
 - migrate_pages(2)
 - cgroup/cpuset migration
 - memory hotremove
 - soft offline

The main benefit is that we can avoid unnecessary thp splits, which helps us
avoid performance decrease when your applications handles NUMA optimization on
their own.

The implementation is similar to that of normal page migration, the key point
is that we modify a pmd to a pmd migration entry in swap-entry like format.
pmd_present() is not simple and it's not enough by itself to determine whether
a given pmd is a pmd migration entry. See patch 3/11 and 5/11 for details.

Here're topics which might be helpful to start discussion:

- at this point, this functionality is limited to x86_64.

- there's alrealy an implementation of thp migration in autonuma code of which
  this patchset doesn't touch anything because it works fine as it is.

- fallback to thp split: current implementation just fails a migration trial if
  thp migration fails. It's possible to retry migration after splitting the thp,
  but that's not included in this version.

Any comments or advices are welcomed.

Thanks,
Naoya Horiguchi
---
Summary:

Naoya Horiguchi (11):
      mm: mempolicy: add queue_pages_node_check()
      mm: thp: introduce CONFIG_ARCH_ENABLE_HUGEPAGE_MIGRATION
      mm: thp: add helpers related to thp/pmd migration
      mm: thp: enable thp migration in generic path
      mm: thp: check pmd migration entry in common path
      mm: soft-dirty: keep soft-dirty bits over thp migration
      mm: hwpoison: fix race between unpoisoning and freeing migrate source page
      mm: hwpoison: soft offline supports thp migration
      mm: mempolicy: mbind and migrate_pages support thp migration
      mm: migrate: move_pages() supports thp migration
      mm: memory_hotplug: memory hotremove supports thp migration

 arch/x86/Kconfig                     |   4 +
 arch/x86/include/asm/pgtable.h       |  28 ++++++
 arch/x86/include/asm/pgtable_64.h    |   2 +
 arch/x86/include/asm/pgtable_types.h |   8 +-
 arch/x86/mm/gup.c                    |   3 +
 fs/proc/task_mmu.c                   |  25 +++--
 include/asm-generic/pgtable.h        |  34 ++++++-
 include/linux/huge_mm.h              |  17 ++++
 include/linux/swapops.h              |  64 +++++++++++++
 mm/Kconfig                           |   3 +
 mm/gup.c                             |   8 ++
 mm/huge_memory.c                     | 175 +++++++++++++++++++++++++++++++++--
 mm/memcontrol.c                      |   2 +
 mm/memory-failure.c                  |  41 ++++----
 mm/memory.c                          |   5 +
 mm/memory_hotplug.c                  |   8 ++
 mm/mempolicy.c                       | 110 ++++++++++++++++------
 mm/migrate.c                         |  57 +++++++++---
 mm/page_isolation.c                  |   8 ++
 mm/rmap.c                            |   7 +-
 20 files changed, 527 insertions(+), 82 deletions(-)

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