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SubjectRe: [RFC v9 PATCH 00/21] memory-hotplug: hot-remove physical memory
On 09/05/2012 05:25 PM, wency@cn.fujitsu.com wrote:
> From: Wen Congyang <wency@cn.fujitsu.com>
>
> This patch series aims to support physical memory hot-remove.
>
> The patches can free/remove the following things:
>
> - acpi_memory_info : [RFC PATCH 4/19]
> - /sys/firmware/memmap/X/{end, start, type} : [RFC PATCH 8/19]
> - iomem_resource : [RFC PATCH 9/19]
> - mem_section and related sysfs files : [RFC PATCH 10-11, 13-16/19]
> - page table of removed memory : [RFC PATCH 12/19]
> - node and related sysfs files : [RFC PATCH 18-19/19]
>
> If you find lack of function for physical memory hot-remove, please let me
> know.

Since patchset is too big, could you add more patchset changelog to
describe how this patchset works? in order that it is easier to review.

>
> 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. memory can't be offlined when CONFIG_MEMCG is selected.
> For example: there is a memory device on node 1. The address range
> is [1G, 1.5G). You will find 4 new directories memory8, memory9, memory10,
> and memory11 under the directory /sys/devices/system/memory/.
> If CONFIG_MEMCG is selected, we will allocate memory to store page cgroup
> when we online pages. When we online memory8, the memory stored page cgroup
> is not provided by this memory device. But when we online memory9, the memory
> stored page cgroup may be provided by memory8. So we can't offline memory8
> now. We should offline the memory in the reversed order.
> When the memory device is hotremoved, we will auto offline memory provided
> by this memory device. But we don't know which memory is onlined first, so
> offlining memory may fail. In such case, you should offline the memory by
> hand before hotremoving the memory device.
> 2. 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
>
> change log of v9:
> [RFC PATCH v9 8/21]
> * add a lock to protect the list map_entries
> * add an indicator to firmware_map_entry to remember whether the memory
> is allocated from bootmem
> [RFC PATCH v9 10/21]
> * change the macro to inline function
> [RFC PATCH v9 19/21]
> * don't offline the node if the cpu on the node is onlined
> [RFC PATCH v9 21/21]
> * create new patch: auto offline page_cgroup when onlining memory block
> failed
>
> change log of v8:
> [RFC PATCH v8 17/20]
> * Fix problems when one node's range include the other nodes
> [RFC PATCH v8 18/20]
> * fix building error when CONFIG_MEMORY_HOTPLUG_SPARSE or CONFIG_HUGETLBFS
> is not defined.
> [RFC PATCH v8 19/20]
> * don't offline node when some memory sections are not removed
> [RFC PATCH v8 20/20]
> * create new patch: clear hwpoisoned flag when onlining pages
>
> change log of v7:
> [RFC PATCH v7 4/19]
> * do not continue if acpi_memory_device_remove_memory() fails.
> [RFC PATCH v7 15/19]
> * handle usemap in register_page_bootmem_info_section() too.
>
> change log of v6:
> [RFC PATCH v6 12/19]
> * fix building error on other archtitectures than x86
>
> [RFC PATCH v6 15-16/19]
> * fix building error on other archtitectures than x86
>
> change log of v5:
> * merge the patchset to clear page table and the patchset to hot remove
> memory(from ishimatsu) to one big patchset.
>
> [RFC PATCH v5 1/19]
> * rename remove_memory() to offline_memory()/offline_pages()
>
> [RFC PATCH v5 2/19]
> * new patch: implement offline_memory(). This function offlines pages,
> update memory block's state, and notify the userspace that the memory
> block's state is changed.
>
> [RFC PATCH v5 4/19]
> * offline and remove memory in acpi_memory_disable_device() too.
>
> [RFC PATCH v5 17/19]
> * new patch: add a new function __remove_zone() to revert the things done
> in the function __add_zone().
>
> [RFC PATCH v5 18/19]
> * flush work befor reseting node device.
>
> change log of v4:
> * remove "memory-hotplug : unify argument of firmware_map_add_early/hotplug"
> from the patch series, since the patch is a bugfix. It is being disccussed
> on other thread. But for testing the patch series, the patch is needed.
> So I added the patch as [PATCH 0/13].
>
> [RFC PATCH v4 2/13]
> * check memory is online or not at remove_memory()
> * add memory_add_physaddr_to_nid() to acpi_memory_device_remove() for
> getting node id
>
> [RFC PATCH v4 3/13]
> * create new patch : check memory is online or not at online_pages()
>
> [RFC PATCH v4 4/13]
> * add __ref section to remove_memory()
> * call firmware_map_remove_entry() before remove_sysfs_fw_map_entry()
>
> [RFC PATCH v4 11/13]
> * rewrite register_page_bootmem_memmap() for removing page used as PT/PMD
>
> change log of v3:
> * rebase to 3.5.0-rc6
>
> [RFC PATCH v2 2/13]
> * remove extra kobject_put()
>
> * The patch was commented by Wen. Wen's comment is
> "acpi_memory_device_remove() should ignore a return value of
> remove_memory() since caller does not care the return value".
> But I did not change it since I think caller should care the
> return value. And I am trying to fix it as follow:
>
> https://lkml.org/lkml/2012/7/5/624
>
> [RFC PATCH v2 4/13]
> * remove a firmware_memmap_entry allocated by kzmalloc()
>
> change log of v2:
> [RFC PATCH v2 2/13]
> * check whether memory block is offline or not before calling offline_memory()
> * check whether section is valid or not in is_memblk_offline()
> * call kobject_put() for each memory_block in is_memblk_offline()
>
> [RFC PATCH v2 3/13]
> * unify the end argument of firmware_map_add_early/hotplug
>
> [RFC PATCH v2 4/13]
> * add release_firmware_map_entry() for freeing firmware_map_entry
>
> [RFC PATCH v2 6/13]
> * add release_memory_block() for freeing memory_block
>
> [RFC PATCH v2 11/13]
> * fix wrong arguments of free_pages()
>
>
> Wen Congyang (8):
> memory-hotplug: implement offline_memory()
> memory-hotplug: store the node id in acpi_memory_device
> memory-hotplug: export the function acpi_bus_remove()
> memory-hotplug: call acpi_bus_remove() to remove memory device
> memory-hotplug: introduce new function arch_remove_memory()
> memory-hotplug: remove sysfs file of node
> memory-hotplug: clear hwpoisoned flag when onlining pages
> memory-hotplug: auto offline page_cgroup when onlining memory block
> failed
>
> Yasuaki Ishimatsu (13):
> memory-hotplug: rename remove_memory() to
> offline_memory()/offline_pages()
> memory-hotplug: offline and remove memory when removing the memory
> device
> memory-hotplug: check whether memory is present or not
> memory-hotplug: remove /sys/firmware/memmap/X sysfs
> memory-hotplug: does not release memory region in PAGES_PER_SECTION
> chunks
> memory-hotplug: add memory_block_release
> memory-hotplug: remove_memory calls __remove_pages
> memory-hotplug: check page type in get_page_bootmem
> memory-hotplug: move register_page_bootmem_info_node and
> put_page_bootmem for sparse-vmemmap
> memory-hotplug: implement register_page_bootmem_info_section of
> sparse-vmemmap
> memory-hotplug: free memmap of sparse-vmemmap
> memory_hotplug: clear zone when the memory is removed
> memory-hotplug: add node_device_release
>
> arch/ia64/mm/discontig.c | 14 +
> arch/ia64/mm/init.c | 16 +
> arch/powerpc/mm/init_64.c | 14 +
> arch/powerpc/mm/mem.c | 14 +
> arch/powerpc/platforms/pseries/hotplug-memory.c | 16 +-
> arch/s390/mm/init.c | 12 +
> arch/s390/mm/vmem.c | 14 +
> arch/sh/mm/init.c | 15 +
> 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 | 10 +
> arch/x86/mm/init_64.c | 331 ++++++++++++++++++
> arch/x86/mm/pageattr.c | 47 ++--
> drivers/acpi/acpi_memhotplug.c | 54 +++-
> drivers/acpi/scan.c | 3 +-
> drivers/base/memory.c | 88 ++++-
> drivers/base/node.c | 11 +
> drivers/firmware/memmap.c | 98 +++++-
> include/acpi/acpi_bus.h | 1 +
> include/linux/firmware-map.h | 6 +
> include/linux/memory.h | 5 +
> include/linux/memory_hotplug.h | 25 +-
> include/linux/mm.h | 5 +-
> include/linux/mmzone.h | 19 +
> mm/memory_hotplug.c | 424 +++++++++++++++++++++--
> mm/page_cgroup.c | 3 +
> mm/sparse.c | 5 +-
> 28 files changed, 1181 insertions(+), 92 deletions(-)
>
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