At 07/17/2012 09:54 AM, Yasuaki Ishimatsu Wrote:
> Hi Wen,
>
> 2012/07/17 10:44, Yasuaki Ishimatsu wrote:
>> Hi Wen,
>>
>> 2012/07/13 12:35, Wen Congyang wrote:
>>> At 07/09/2012 06:24 PM, Yasuaki Ishimatsu Wrote:
>>>> acpi_memory_device_remove() has been prepared to remove physical memory.
>>>> But, the function only frees acpi_memory_device currentlry.
>>>>
>>>> The patch adds following functions into acpi_memory_device_remove():
>>>> - offline memory
>>>> - remove physical memory (only return -EBUSY)
>>>> - free acpi_memory_device
>>>>
>>>> CC: David Rientjes <rient...@google.com>
>>>> CC: Jiang Liu <liu...@gmail.com>
>>>> CC: Len Brown <len.br...@intel.com>
>>>> CC: Benjamin Herrenschmidt <b...@kernel.crashing.org>
>>>> CC: Paul Mackerras <pau...@samba.org>
>>>> CC: Christoph Lameter <c...@linux.com>
>>>> Cc: Minchan Kim <minchan....@gmail.com>
>>>> CC: Andrew Morton <a...@linux-foundation.org>
>>>> CC: KOSAKI Motohiro <kosaki.motoh...@jp.fujitsu.com>
>>>> CC: Wen Congyang <we...@cn.fujitsu.com>
>>>> Signed-off-by: Yasuaki Ishimatsu <isimatu.yasu...@jp.fujitsu.com>
>>>>
>>>> ---
>>>> drivers/acpi/acpi_memhotplug.c | 26 +++++++++++++++++++++++++-
>>>> drivers/base/memory.c | 39
>>>> +++++++++++++++++++++++++++++++++++++++
>>>> include/linux/memory.h | 5 +++++
>>>> include/linux/memory_hotplug.h | 1 +
>>>> mm/memory_hotplug.c | 8 ++++++++
>>>> 5 files changed, 78 insertions(+), 1 deletion(-)
>>>>
>>>> Index: linux-3.5-rc6/drivers/acpi/acpi_memhotplug.c
>>>> ===================================================================
>>>> --- linux-3.5-rc6.orig/drivers/acpi/acpi_memhotplug.c 2012-07-09
>>>> 18:08:29.946888653 +0900
>>>> +++ linux-3.5-rc6/drivers/acpi/acpi_memhotplug.c 2012-07-09
>>>> 18:08:43.470719531 +0900
>>>> @@ -29,6 +29,7 @@
>>>> #include <linux/module.h>
>>>> #include <linux/init.h>
>>>> #include <linux/types.h>
>>>> +#include <linux/memory.h>
>>>> #include <linux/memory_hotplug.h>
>>>> #include <linux/slab.h>
>>>> #include <acpi/acpi_drivers.h>
>>>> @@ -452,12 +453,35 @@ static int acpi_memory_device_add(struct
>>>> static int acpi_memory_device_remove(struct acpi_device *device, int
>>>> type)
>>>> {
>>>> struct acpi_memory_device *mem_device = NULL;
>>>> -
>>>> + struct acpi_memory_info *info, *tmp;
>>>> + int result;
>>>> + int node;
>>>>
>>>> if (!device || !acpi_driver_data(device))
>>>> return -EINVAL;
>>>>
>>>> mem_device = acpi_driver_data(device);
>>>> +
>>>> + node = acpi_get_node(mem_device->device->handle);
>>>> +
>>>> + list_for_each_entry_safe(info, tmp, &mem_device->res_list, list) {
>>>> + if (!info->enabled)
>>>> + continue;
>>>> +
>>>> + if (!is_memblk_offline(info->start_addr, info->length)) {
>>>> + result = offline_memory(info->start_addr, info->length);
>>>> + if (result)
>>>> + return result;
>>>> + }
>>>> +
>>>> + result = remove_memory(node, info->start_addr, info->length);
>>>
>>> The user may online the memory between offline_memory() and remove_memory().
>>> So I think we should lock memory hotplug before check the memory's status
>>> and release it after remove_memory().
>>
>> How about get "mem_block->state_mutex" of removed memory? When offlining
>> memory, we need to change "memory_block->state" into "MEM_OFFLINE".
>> In this case, we get mem_block->state_mutex. So I think the mutex lock
>> is beneficial.
>
> It is not good idea since remove_memory frees mem_block structure...
> Do you have any ideas?
Hmm, split offline_memory() to 2 functions: offline_pages() and
__offline_pages()
offline_pages()
lock_memory_hotplug();
__offline_pages();
unlock_memory_hotplug();
and implement remove_memory() like this:
remove_memory()
lock_memory_hotplug()
if (!is_memblk_offline()) {
__offline_pages();
}
// cleanup
unlock_memory_hotplug();
What about this?
Thanks
Wen Congyang
>
> Thanks,
> Yasuaki Ishimatsu
>
>> Thanks,
>> Yasuaki Ishimatsu
>>
>>>
>>> Thanks
>>> Wen Congyang
>>>
>>>> + if (result)
>>>> + return result;
>>>> +
>>>> + list_del(&info->list);
>>>> + kfree(info);
>>>> + }
>>>> +
>>>> kfree(mem_device);
>>>>
>>>> return 0;
>>>> Index: linux-3.5-rc6/include/linux/memory_hotplug.h
>>>> ===================================================================
>>>> --- linux-3.5-rc6.orig/include/linux/memory_hotplug.h 2012-07-09
>>>> 18:08:29.955888542 +0900
>>>> +++ linux-3.5-rc6/include/linux/memory_hotplug.h 2012-07-09
>>>> 18:08:43.471719518 +0900
>>>> @@ -233,6 +233,7 @@ static inline int is_mem_section_removab
>>>> extern int mem_online_node(int nid);
>>>> extern int add_memory(int nid, u64 start, u64 size);
>>>> extern int arch_add_memory(int nid, u64 start, u64 size);
>>>> +extern int remove_memory(int nid, u64 start, u64 size);
>>>> extern int offline_memory(u64 start, u64 size);
>>>> extern int sparse_add_one_section(struct zone *zone, unsigned long
>>>> start_pfn,
>>>> int
>>>> nr_pages);
>>>> Index: linux-3.5-rc6/mm/memory_hotplug.c
>>>> ===================================================================
>>>> --- linux-3.5-rc6.orig/mm/memory_hotplug.c 2012-07-09 18:08:29.953888567
>>>> +0900
>>>> +++ linux-3.5-rc6/mm/memory_hotplug.c 2012-07-09 18:08:43.476719455
>>>> +0900
>>>> @@ -659,6 +659,14 @@ out:
>>>> }
>>>> EXPORT_SYMBOL_GPL(add_memory);
>>>>
>>>> +int remove_memory(int nid, u64 start, u64 size)
>>>> +{
>>>> + return -EBUSY;
>>>> +
>>>> +}
>>>> +EXPORT_SYMBOL_GPL(remove_memory);
>>>> +
>>>> +
>>>> #ifdef CONFIG_MEMORY_HOTREMOVE
>>>> /*
>>>> * A free page on the buddy free lists (not the per-cpu lists) has
>>>> PageBuddy
>>>> Index: linux-3.5-rc6/drivers/base/memory.c
>>>> ===================================================================
>>>> --- linux-3.5-rc6.orig/drivers/base/memory.c 2012-07-09
>>>> 18:08:29.947888640 +0900
>>>> +++ linux-3.5-rc6/drivers/base/memory.c 2012-07-09 18:10:54.880076739
>>>> +0900
>>>> @@ -70,6 +70,45 @@ void unregister_memory_isolate_notifier(
>>>> }
>>>> EXPORT_SYMBOL(unregister_memory_isolate_notifier);
>>>>
>>>> +bool is_memblk_offline(unsigned long start, unsigned long size)
>>>> +{
>>>> + struct memory_block *mem = NULL;
>>>> + struct mem_section *section;
>>>> + unsigned long start_pfn, end_pfn;
>>>> + unsigned long pfn, section_nr;
>>>> +
>>>> + start_pfn = PFN_DOWN(start);
>>>> + end_pfn = start_pfn + PFN_DOWN(start);
>>>> +
>>>> + for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
>>>> + section_nr = pfn_to_section_nr(pfn);
>>>> + if (!present_section_nr(section_nr));
>>>> + continue;
>>>> +
>>>> + section = __nr_to_section(section_nr);
>>>> + /* same memblock? */
>>>> + if (mem)
>>>> + if((section_nr >= mem->start_section_nr) &&
>>>> + (section_nr <= mem->end_section_nr))
>>>> + continue;
>>>> +
>>>> + mem = find_memory_block_hinted(section, mem);
>>>> + if (!mem)
>>>> + continue;
>>>> + if (mem->state == MEM_OFFLINE)
>>>> + continue;
>>>> +
>>>> + kobject_put(&mem->dev.kobj);
>>>> + return false;
>>>> + }
>>>> +
>>>> + if (mem)
>>>> + kobject_put(&mem->dev.kobj);
>>>> +
>>>> + return true;
>>>> +}
>>>> +EXPORT_SYMBOL(is_memblk_offline);
>>>> +
>>>> /*
>>>> * register_memory - Setup a sysfs device for a memory block
>>>> */
>>>> Index: linux-3.5-rc6/include/linux/memory.h
>>>> ===================================================================
>>>> --- linux-3.5-rc6.orig/include/linux/memory.h 2012-07-08
>>>> 09:23:56.000000000 +0900
>>>> +++ linux-3.5-rc6/include/linux/memory.h 2012-07-09 18:08:43.484719355
>>>> +0900
>>>> @@ -106,6 +106,10 @@ static inline int memory_isolate_notify(
>>>> {
>>>> return 0;
>>>> }
>>>> +static inline bool is_memblk_offline(unsigned long start, unsigned long
>>>> size)
>>>> +{
>>>> + return false;
>>>> +}
>>>> #else
>>>> extern int register_memory_notifier(struct notifier_block *nb);
>>>> extern void unregister_memory_notifier(struct notifier_block *nb);
>>>> @@ -120,6 +124,7 @@ extern int memory_isolate_notify(unsigne
>>>> extern struct memory_block *find_memory_block_hinted(struct mem_section
>>>> *,
>>>> struct
>>>> memory_block *);
>>>> extern struct memory_block *find_memory_block(struct mem_section *);
>>>> +extern bool is_memblk_offline(unsigned long start, unsigned long size);
>>>> #define CONFIG_MEM_BLOCK_SIZE (PAGES_PER_SECTION<<PAGE_SHIFT)
>>>> enum mem_add_context { BOOT, HOTPLUG };
>>>> #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
>>>>
>>>>
>>>
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>>> see: http://www.linux-mm.org/ .
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>>>
>>
>>
>>
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>
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