[PATCH v5 00/14] memory-hotplug: hot-remove physical memory

Tang Chen tangchen at cn.fujitsu.com
Mon Dec 24 23:09:10 EST 2012

Hi Andrew,

Here is the physical memory hot-remove patch-set based on 3.8rc-1.

This patch-set aims to implement physical memory hot-removing.

The patches can free/remove the following things:

  - /sys/firmware/memmap/X/{end, start, type} : [PATCH 4/14]
  - memmap of sparse-vmemmap                  : [PATCH 6,7,8,10/14]
  - page table of removed memory              : [RFC PATCH 7,8,10/14]
  - node and related sysfs files              : [RFC PATCH 13-14/14]

How to test this patchset?
1. apply this patchset and build the kernel. MEMORY_HOTPLUG, MEMORY_HOTREMOVE,
   ACPI_HOTPLUG_MEMORY must be selected.
2. load the module acpi_memhotplug
3. hotplug the memory device(it depends on your hardware)
   You will see the memory device under the directory /sys/bus/acpi/devices/.
   Its name is PNP0C80:XX.
4. online/offline pages provided by this memory device
   You can write online/offline to /sys/devices/system/memory/memoryX/state to
   online/offline pages provided by this memory device
5. hotremove the memory device
   You can hotremove the memory device by the hardware, or writing 1 to

Note: if the memory provided by the memory device is used by the kernel, it
can't be offlined. It is not a bug.

Changelogs from v4 to v5:
 Patch7: new patch, move pgdat_resize_lock into sparse_remove_one_section() to
         avoid disabling irq because we need flush tlb when free pagetables.
 Patch8: new patch, pick up some common APIs that are used to free direct mapping
         and vmemmap pagetables.
 Patch9: free direct mapping pagetables on x86_64 arch.
 Patch10: free vmemmap pagetables.
 Patch11: since freeing memmap with vmemmap has been implemented, the config
          macro CONFIG_SPARSEMEM_VMEMMAP when defining __remove_section() is
          no longer needed.
 Patch13: no need to modify acpi_memory_disable_device() since it was removed,
          and add nid parameter when calling remove_memory().

Changelogs from v3 to v4:
 Patch7: remove unused codes.
 Patch8: fix nr_pages that is passed to free_map_bootmem()

Changelogs from v2 to v3:
 Patch9: call sync_global_pgds() if pgd is changed
 Patch10: fix a problem int the patch

Changelogs from v1 to v2:
 Patch1: new patch, offline memory twice. 1st iterate: offline every non primary
         memory block. 2nd iterate: offline primary (i.e. first added) memory

 Patch3: new patch, no logical change, just remove reduntant codes.

 Patch9: merge the patch from wujianguo into this patch. flush tlb on all cpu
         after the pagetable is changed.

 Patch12: new patch, free node_data when a node is offlined.

Tang Chen (5):
  memory-hotplug: move pgdat_resize_lock into
  memory-hotplug: remove page table of x86_64 architecture
  memory-hotplug: remove memmap of sparse-vmemmap
  memory-hotplug: Integrated __remove_section() of
  memory-hotplug: remove sysfs file of node

Wen Congyang (5):
  memory-hotplug: try to offline the memory twice to avoid dependence
  memory-hotplug: remove redundant codes
  memory-hotplug: introduce new function arch_remove_memory() for
    removing page table depends on architecture
  memory-hotplug: Common APIs to support page tables hot-remove
  memory-hotplug: free node_data when a node is offlined

Yasuaki Ishimatsu (4):
  memory-hotplug: check whether all memory blocks are offlined or not
    when removing memory
  memory-hotplug: remove /sys/firmware/memmap/X sysfs
  memory-hotplug: implement register_page_bootmem_info_section of
  memory-hotplug: memory_hotplug: clear zone when removing the memory

 arch/arm64/mm/mmu.c                  |    3 +
 arch/ia64/mm/discontig.c             |   10 +
 arch/ia64/mm/init.c                  |   18 ++
 arch/powerpc/mm/init_64.c            |   10 +
 arch/powerpc/mm/mem.c                |   12 +
 arch/s390/mm/init.c                  |   12 +
 arch/s390/mm/vmem.c                  |   10 +
 arch/sh/mm/init.c                    |   17 ++
 arch/sparc/mm/init_64.c              |   10 +
 arch/tile/mm/init.c                  |    8 +
 arch/x86/include/asm/pgtable_types.h |    1 +
 arch/x86/mm/init_32.c                |   12 +
 arch/x86/mm/init_64.c                |  382 ++++++++++++++++++++++++++++++++
 arch/x86/mm/pageattr.c               |   47 ++--
 drivers/acpi/acpi_memhotplug.c       |    8 +-
 drivers/base/memory.c                |    6 +
 drivers/firmware/memmap.c            |   98 ++++++++-
 include/linux/bootmem.h              |    1 +
 include/linux/firmware-map.h         |    6 +
 include/linux/memory_hotplug.h       |   15 +-
 include/linux/mm.h                   |    4 +-
 mm/memory_hotplug.c                  |  406 ++++++++++++++++++++++++++++++++--
 mm/sparse.c                          |    8 +-
 23 files changed, 1043 insertions(+), 61 deletions(-)

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