[PATCH v3 00/11] mm/memory_hotplug: Factor out memory block devicehandling

[David Hildenbrand <david@redhat.com>]

We only want memory block devices for memory to be onlined/offlined
(add/remove from the buddy). This is required so user space can
online/offline memory and kdump gets notified about newly onlined memory.

Let's factor out creation/removal of memory block devices. This helps
to further cleanup arch_add_memory/arch_remove_memory() and to make
implementation of new features easier - especially sub-section
memory hot add from Dan.

Anshuman Khandual is currently working on arch_remove_memory(). I added
a temporary solution via "arm64/mm: Add temporary arch_remove_memory()
implementation", that is sufficient as a firsts tep in the context of
this series. (we don't cleanup page tables in case anything goes
wrong already)

Did a quick sanity test with DIMM plug/unplug, making sure all devices
and sysfs links properly get added/removed. Compile tested on s390x and
x86-64.

Based on next/master.

Next refactoring on my list will be making sure that remove_memory()
will never deal with zones / access "struct pages". Any kind of zone
handling will have to be done when offlining system memory / before
removing device memory. I am thinking about remove_pfn_range_from_zone()",
du undo everything "move_pfn_range_to_zone()" did.

v2 -> v3:
- Add "s390x/mm: Fail when an altmap is used for arch_add_memory()"
- Add "arm64/mm: Add temporary arch_remove_memory() implementation"
- Add "drivers/base/memory: Pass a block_id to init_memory_block()"
- Various changes to "mm/memory_hotplug: Create memory block devices
  after arch_add_memory()" and "mm/memory_hotplug: Create memory block
  devices after arch_add_memory()" due to switching from sections to
  block_id's.

v1 -> v2:
- s390x/mm: Implement arch_remove_memory()
-- remove mapping after "__remove_pages"

David Hildenbrand (11):
  mm/memory_hotplug: Simplify and fix check_hotplug_memory_range()
  s390x/mm: Fail when an altmap is used for arch_add_memory()
  s390x/mm: Implement arch_remove_memory()
  arm64/mm: Add temporary arch_remove_memory() implementation
  drivers/base/memory: Pass a block_id to init_memory_block()
  mm/memory_hotplug: Allow arch_remove_pages() without
    CONFIG_MEMORY_HOTREMOVE
  mm/memory_hotplug: Create memory block devices after arch_add_memory()
  mm/memory_hotplug: Drop MHP_MEMBLOCK_API
  mm/memory_hotplug: Remove memory block devices before
    arch_remove_memory()
  mm/memory_hotplug: Make unregister_memory_block_under_nodes() never
    fail
  mm/memory_hotplug: Remove "zone" parameter from
    sparse_remove_one_section

 arch/arm64/mm/mmu.c            |  17 +++++
 arch/ia64/mm/init.c            |   2 -
 arch/powerpc/mm/mem.c          |   2 -
 arch/s390/mm/init.c            |  18 +++--
 arch/sh/mm/init.c              |   2 -
 arch/x86/mm/init_32.c          |   2 -
 arch/x86/mm/init_64.c          |   2 -
 drivers/base/memory.c          | 134 +++++++++++++++++++--------------
 drivers/base/node.c            |  27 +++----
 include/linux/memory.h         |   6 +-
 include/linux/memory_hotplug.h |  12 +--
 include/linux/node.h           |   7 +-
 mm/memory_hotplug.c            |  44 +++++------
 mm/sparse.c                    |  10 +--
 14 files changed, 140 insertions(+), 145 deletions(-)

-- 
2.20.1