Hi Jiang,
2012/07/01 0:51, Jiang Liu wrote:
> On 06/27/2012 01:44 PM, Yasuaki Ishimatsu wrote:
>> When offline_pages() is called to offlined memory, the function fails since
>> all memory has been offlined. In this case, the function should succeed.
>> The patch adds the check function into offline_pages().
>>
>> CC: Len Brown <len.brown@xxxxxxxxx>
>> CC: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
>> CC: Paul Mackerras <paulus@xxxxxxxxx>
>> CC: Christoph Lameter <cl@xxxxxxxxx>
>> Cc: Minchan Kim <minchan.kim@xxxxxxxxx>
>> CC: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
>> CC: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
>> CC: Wen Congyang <wency@xxxxxxxxxxxxxx>
>> Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx>
>>
>> ---
>> drivers/base/memory.c | 20 ++++++++++++++++++++
>> include/linux/memory.h | 1 +
>> mm/memory_hotplug.c | 5 +++++
>> 3 files changed, 26 insertions(+)
>>
>> Index: linux-3.5-rc4/drivers/base/memory.c
>> ===================================================================
>> --- linux-3.5-rc4.orig/drivers/base/memory.c 2012-06-26 13:28:16.726211752 +0900
>> +++ linux-3.5-rc4/drivers/base/memory.c 2012-06-26 13:34:22.423639904 +0900
>> @@ -70,6 +70,26 @@ void unregister_memory_isolate_notifier(
>> }
>> EXPORT_SYMBOL(unregister_memory_isolate_notifier);
>>
>> +bool memory_is_offline(unsigned long start_pfn, unsigned long end_pfn)
>> +{
>> + struct memory_block *mem;
>> + struct mem_section *section;
>> + unsigned long pfn, section_nr;
>> +
>> + for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
>> + section_nr = pfn_to_section_nr(pfn);
>> + section = __nr_to_section(section_nr);
>> + mem = find_memory_block(section);
> Seems find_memory_block_hinted() is more efficient than find_memory_block() here.
Thanks. I'll update it.
Thanks,
Yasuaki Ishimatsu
>
>> + if (!mem)
>> + continue;
>> + if (mem->state == MEM_OFFLINE)
>> + continue;
>> + return false;
>> + }
>> +
>> + return true;
>> +}
>> +
>> /*
>> * register_memory - Setup a sysfs device for a memory block
>> */
>> Index: linux-3.5-rc4/include/linux/memory.h
>> ===================================================================
>> --- linux-3.5-rc4.orig/include/linux/memory.h 2012-06-25 04:53:04.000000000 +0900
>> +++ linux-3.5-rc4/include/linux/memory.h 2012-06-26 13:34:22.424639891 +0900
>> @@ -120,6 +120,7 @@ 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 memory_is_offline(unsigned long start_pfn, unsigned long end_pfn);
>> #define CONFIG_MEM_BLOCK_SIZE (PAGES_PER_SECTION<<PAGE_SHIFT)
>> enum mem_add_context { BOOT, HOTPLUG };
>> #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
>> Index: linux-3.5-rc4/mm/memory_hotplug.c
>> ===================================================================
>> --- linux-3.5-rc4.orig/mm/memory_hotplug.c 2012-06-26 13:28:16.743211538 +0900
>> +++ linux-3.5-rc4/mm/memory_hotplug.c 2012-06-26 13:48:38.264940468 +0900
>> @@ -887,6 +887,11 @@ static int __ref offline_pages(unsigned
>>
>> lock_memory_hotplug();
>>
>> + if (memory_is_offline(start_pfn, end_pfn)) {
>> + ret = 0;
>> + goto out;
>> + }
>> +
>> zone = page_zone(pfn_to_page(start_pfn));
>> node = zone_to_nid(zone);
>> nr_pages = end_pfn - start_pfn;
>>
>> --
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>
>
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