[PATCH v2 0/5] Memory hotplug support for arm64 - complete patchset v2

[ar@linux.vnet.ibm.com (Andrea Reale)]

Hi all,

this is a second round of patches to introduce memory hotplug and
hotremove support for arm64. It builds on the work previously published at
[1] and it implements the feedback received in the first round of reviews.

The patchset applies and has been tested on commit bebc6082da0a ("Linux
4.14"). 

Due to a small regression introduced with commit 8135d8926c08
("mm: memory_hotplug: memory hotremove supports thp migration"), you
will need to appy patch [2] first, until the fix is not upstreamed.

Comments and feedback are gold.

[1] https://lkml.org/lkml/2017/4/11/536
[2] https://lkml.org/lkml/2017/11/20/902

Changes v1->v2:
- swapper pgtable updated in place on hot add, avoiding unnecessary copy
- stop_machine used to updated swapper on hot add, avoiding races
- introduced check on offlining state before hot remove
- new memblock flag used to mark partially unused vmemmap pages, avoiding
  the nasty 0xFD hack used in the prev rev (and in x86 hot remove code)
- proper cleaning sequence for p[um]ds,ptes and related TLB management
- Removed macros that changed hot remove behavior based on number
  of pgtable levels. Now this is hidden in the pgtable traversal macros.
- Check on the corner case where P[UM]Ds would have to be split during
  hot remove: now this is forbidden.
- Minor fixes and refactoring.

Andrea Reale (4):
  mm: memory_hotplug: Remove assumption on memory state before hotremove
  mm: memory_hotplug: memblock to track partially removed vmemmap mem
  mm: memory_hotplug: Add memory hotremove probe device
  mm: memory-hotplug: Add memory hot remove support for arm64

Maciej Bielski (1):
  mm: memory_hotplug: Memory hotplug (add) support for arm64

 arch/arm64/Kconfig             |  15 +
 arch/arm64/configs/defconfig   |   2 +
 arch/arm64/include/asm/mmu.h   |   7 +
 arch/arm64/mm/init.c           | 116 ++++++++
 arch/arm64/mm/mmu.c            | 609 ++++++++++++++++++++++++++++++++++++++++-
 drivers/acpi/acpi_memhotplug.c |   2 +-
 drivers/base/memory.c          |  34 ++-
 include/linux/memblock.h       |  12 +
 include/linux/memory_hotplug.h |   9 +-
 mm/memblock.c                  |  32 +++
 mm/memory_hotplug.c            |  13 +-
 11 files changed, 835 insertions(+), 16 deletions(-)

-- 
2.7.4