[Part3 PATCH v2 0/4] Support hot-remove local pagetable pages.

[Tang Chen]

The following patch-set from Yinghai allocates pagetables to local nodes.
v1: https://lkml.org/lkml/2013/3/7/642
v2: https://lkml.org/lkml/2013/3/10/47
v3: https://lkml.org/lkml/2013/4/4/639
v4: https://lkml.org/lkml/2013/4/11/829

Since pagetable pages are used by the kernel, they cannot be offlined.
As a result, they cannot be hot-remove.

This patch fix this problem with the following solution:

     1.   Introduce a new bootmem type LOCAL_NODE_DATAL, and register local
          pagetable pages as LOCAL_NODE_DATAL by setting page->lru.next to
          LOCAL_NODE_DATAL, just like we register SECTION_INFO pages.

     2.   Skip LOCAL_NODE_DATAL pages in offline/online procedures. When the
          whole memory block they reside in is offlined, the kernel can
          still access the pagetables.
          (This changes the semantics of offline/online a little bit.)

     3.   Do not free LOCAL_NODE_DATAL pages to buddy system because they
          were skipped when in offline/online procedures. The memory block
          they reside in could have been offlined.

Anyway, this problem should be fixed. Any better idea is welcome.

Change log:
v1 -> v2:
        patch2: As suggested by Wu Jianguo, define a macro to check if a page
                cantains local node data.
        patch4: As suggested by Wu Jianguo, prevent freeing LOCAL_NODE_DATA
                pages in free_pagetable() instead of in put_page_bootmem().

Tang Chen (4):
  bootmem, mem-hotplug: Register local pagetable pages with
    LOCAL_NODE_DATA when freeing bootmem.
  mem-hotplug: Skip LOCAL_NODE_DATA pages in memory offline procedure.
  mem-hotplug: Skip LOCAL_NODE_DATA pages in memory online procedure.
  mem-hotplug: Do not free LOCAL_NODE_DATA pages to buddy system in
    hot-remove procedure.

 arch/x86/mm/init_64.c          |   10 +++++++-
 include/linux/memblock.h       |   22 +++++++++++++++++
 include/linux/memory_hotplug.h |   20 +++++++++++++--
 mm/memblock.c                  |   52 ++++++++++++++++++++++++++++++++++++++++
 mm/memory_hotplug.c            |   31 +++++++++++++++++++++++
 mm/page_alloc.c                |   15 ++++++++++-
 mm/page_isolation.c            |    5 ++++
 7 files changed, 149 insertions(+), 6 deletions(-)

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