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Message-ID: <50691FBA.5080107@jp.fujitsu.com>
Date: Mon, 1 Oct 2012 13:44:42 +0900
From: Yasuaki Ishimatsu <isimatu.yasuaki@...fujitsu.com>
To: Ni zhan Chen <nizhan.chen@...il.com>
CC: <wency@...fujitsu.com>, <x86@...nel.org>, <linux-mm@...ck.org>,
<linux-kernel@...r.kernel.org>, <linuxppc-dev@...ts.ozlabs.org>,
<linux-acpi@...r.kernel.org>, <linux-s390@...r.kernel.org>,
<linux-sh@...r.kernel.org>, <linux-ia64@...r.kernel.org>,
<cmetcalf@...era.com>, <sparclinux@...r.kernel.org>,
<rientjes@...gle.com>, <liuj97@...il.com>, <len.brown@...el.com>,
<benh@...nel.crashing.org>, <paulus@...ba.org>, <cl@...ux.com>,
<minchan.kim@...il.com>, <akpm@...ux-foundation.org>,
<kosaki.motohiro@...fujitsu.com>
Subject: Re: [RFC v9 PATCH 00/21] memory-hotplug: hot-remove physical memory
Hi Chen,
2012/09/29 17:19, Ni zhan Chen wrote:
> On 09/05/2012 05:25 PM, wency@...fujitsu.com wrote:
>> From: Wen Congyang <wency@...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.
>>
>> 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
>
> Hi Yasuaki,
>
> where is the acpi_memhotplug module?
If you build acpi_memhotplug as module, it is created under
/lib/modules/<kernel-version>/driver/acpi/ directory. It depends
on config ACPI_HOTPLUG_MEMORY. The confing is [*], it becomes built-in
function. So you don't need to care about it.
Thanks,
Yasuaki Ishimatsu
>
>> 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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>
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