linux-kernel - [PATCH 0/4] Support hot-remove local pagetable pages.

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Date:	Fri, 24 May 2013 17:30:03 +0800
From:	Tang Chen <tangchen@...fujitsu.com>
To:	akpm@...ux-foundation.org, mgorman@...e.de, mingo@...hat.com,
	hpa@...or.com, minchan@...nel.org, wency@...fujitsu.com,
	laijs@...fujitsu.com, yinghai@...nel.org, jiang.liu@...wei.com,
	tj@...nel.org, liwanp@...ux.vnet.ibm.com,
	isimatu.yasuaki@...fujitsu.com, kamezawa.hiroyu@...fujitsu.com
Cc:	linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: [PATCH 0/4] Support hot-remove local pagetable pages.

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 LOCA_NODE_DATAL, and register local 
          pagetable pages as LOCA_NODE_DATAL by setting page->lru.next to
          LOCA_NODE_DATAL, just like we register SECTION_INFO pages.

     2.   Skip LOCA_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 LOCA_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.

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          |    2 +
 include/linux/memblock.h       |   22 +++++++++++++++++
 include/linux/memory_hotplug.h |   13 ++++++++-
 mm/memblock.c                  |   52 ++++++++++++++++++++++++++++++++++++++++
 mm/memory_hotplug.c            |   42 +++++++++++++++++++++++++++++++-
 mm/page_alloc.c                |   18 ++++++++++++-
 mm/page_isolation.c            |    6 ++++
 7 files changed, 150 insertions(+), 5 deletions(-)

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