[PART1 Patch 0/3] mm, memory-hotplug: allow to online movable memory

[Wen Congyang]

From: Lai Jiangshan <laijs@xxxxxxxxxxxxxx>

This patch is part1 of the following patchset:
    https://lkml.org/lkml/2012/10/29/319

The patchset is based on Linus's tree with these three patches already applied:
    https://lkml.org/lkml/2012/10/24/151
    https://lkml.org/lkml/2012/10/26/150

Movable memory is a very important concept of memory-management,
we need to consolidate it and make use of it on systems.

Movable memory is needed for
    anti-fragmentation(hugepage, big-order allocation...)
    logic hot-remove(virtualization, Memory capacity on Demand)
    physic hot-remove(power-saving, hardware partitioning, hardware fault management)

All these require dynamic configuring the memory and making better utilities of
memories and safer. We also need physic hot-remove, so we need movable node too.
(Although some systems support physic-memory-migration, we don't require all
memory on physic-node is movable, but movable node is still needed here
for logic-node if we want to make physic-migration is transparent)

We add dynamic configuration commands "online_movalbe" and "online_kernel" in
this patchset, and you can't make a movable node(it will be implemented in
part4).

Usage:
1. online_movable:
   echo online_movable >/sys/devices/system/memory/memoryX/state
   The memory must be offlined before doing this.
2. online_kernel:
   echo online_kernel >/sys/devices/system/memory/memoryX/state
   The memory must be offlined before doing this.
3. online:
   echo online_kernel >/sys/devices/system/memory/memoryX/state
   The memory must be offline before doing this. This operation does't change
   the memory's attribute: movable or normal/high

Note:
   You only can move the highest memory in normal/high zone to movable zone,
   and only can move the lowest memory in movable zone to normal/high zone.

Lai Jiangshan (3):
  mm, memory-hotplug: dynamic configure movable memory and portion
    memory
  memory_hotplug: handle empty zone when online_movable/online_kernel
  memory_hotplug: ensure every online node has NORMAL memory

 Documentation/memory-hotplug.txt |  14 ++-
 drivers/base/memory.c            |  27 +++---
 include/linux/memory_hotplug.h   |  13 ++-
 mm/memory_hotplug.c              | 180 ++++++++++++++++++++++++++++++++++++++-
 4 files changed, 221 insertions(+), 13 deletions(-)

-- 
1.8.0

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