At 10/23/2012 06:30 PM, Ni zhan Chen Wrote:

On 10/23/2012 06:30 PM, wency@cn.fujitsu.com wrote:

quoted

From: Wen Congyang <redacted>

The patchset doesn't support kernel memory hot-remove, correct? If the
answer is yes, you should point out in your patchset changelog.

The answer is no. If you only apply this patchset, you only can hotremove
the memory by SCI. If you want to hotremove it by writing 1 to the file
/sys/bus/acpi/devices/PNP0C80:XX/eject, you should apply the following
patchset:
https://lkml.org/lkml/2012/10/19/156

Thanks
Wen Congyang

quoted

The patch-set was divided from following thread's patch-set.

https://lkml.org/lkml/2012/9/5/201

The last version of this patchset:
https://lkml.org/lkml/2012/10/5/469

If you want to know the reason, please read following thread.

https://lkml.org/lkml/2012/10/2/83

The patch-set has only the function of kernel core side for physical
memory hot remove. So if you use the patch, please apply following
patches.

- bug fix for memory hot remove
   https://lkml.org/lkml/2012/10/19/56
   - acpi framework
   https://lkml.org/lkml/2012/10/19/156

The patches can free/remove the following things:

   - /sys/firmware/memmap/X/{end, start, type} : [PATCH 2/10]
   - mem_section and related sysfs files       : [PATCH 3-4/10]
   - memmap of sparse-vmemmap                  : [PATCH 5-7/10]
   - page table of removed memory              : [RFC PATCH 8/10]
   - node and related sysfs files              : [RFC PATCH 9-10/10]

* [PATCH 2/10] checks whether the memory can be removed or not.

If you find lack of function for physical memory hot-remove, please
let me
know.

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
    /sys/bus/acpi/devices/PNP0C80:XX/eject.

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

Known problems:
1. hotremoving memory device may cause kernel panicked
    This bug will be fixed by Liu Jiang's patch:
    https://lkml.org/lkml/2012/7/3/1


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
          block.

  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

Wen Congyang (6):
   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: remove page table of x86_64 architecture
   memory-hotplug: remove sysfs file of node
   memory-hotplug: free node_data when a node is offlined

Yasuaki Ishimatsu (6):
   memory-hotplug: check whether all memory blocks are offlined or not
     when removing memory
   memory-hotplug: remove /sys/firmware/memmap/X sysfs
   memory-hotplug: unregister memory section on SPARSEMEM_VMEMMAP
   memory-hotplug: implement register_page_bootmem_info_section of
     sparse-vmemmap
   memory-hotplug: remove memmap of sparse-vmemmap
   memory-hotplug: memory_hotplug: clear zone when removing the memory

  arch/ia64/mm/discontig.c             |   14 ++
  arch/ia64/mm/init.c                  |   18 ++
  arch/powerpc/mm/init_64.c            |   14 ++
  arch/powerpc/mm/mem.c                |   12 +
  arch/s390/mm/init.c                  |   12 +
  arch/s390/mm/vmem.c                  |   14 ++
  arch/sh/mm/init.c                    |   17 ++
  arch/sparc/mm/init_64.c              |   14 ++
  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                |  409
++++++++++++++++++++++++++++++++++
  arch/x86/mm/pageattr.c               |   47 ++--
  drivers/acpi/acpi_memhotplug.c       |    8 +-
  drivers/base/memory.c                |    6 +
  drivers/firmware/memmap.c            |   98 ++++++++-
  include/linux/firmware-map.h         |    6 +
  include/linux/memory_hotplug.h       |   15 +-
  include/linux/mm.h                   |    5 +-
  mm/memory_hotplug.c                  |  409
++++++++++++++++++++++++++++++++--
  mm/sparse.c                          |    5 +-
  21 files changed, 1087 insertions(+), 57 deletions(-)

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