Re: [RFC PATCH v4 2/13] memory-hotplug : add physical memory hotplugcode to acpi_memory_device_remove

From: Yasuaki Ishimatsu
Date: Thu Jul 19 2012 - 05:33:22 EST


Hi Wen,

2012/07/19 16:23, Wen Congyang wrote:
> At 07/18/2012 06:06 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. It only check whether memory is online or not.
>> - free acpi_memory_device
>>
>> CC: David Rientjes <rientjes@xxxxxxxxxx>
>> CC: Jiang Liu <liuj97@xxxxxxxxx>
>> 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/acpi/acpi_memhotplug.c | 27 ++++++++++++++++++++++++++-
>> drivers/base/memory.c | 39 +++++++++++++++++++++++++++++++++++++++
>> include/linux/memory.h | 5 +++++
>> include/linux/memory_hotplug.h | 5 +++++
>> mm/memory_hotplug.c | 22 ++++++++++++++++++++++
>> 5 files changed, 97 insertions(+), 1 deletion(-)
>>
>> Index: linux-3.5-rc6/drivers/acpi/acpi_memhotplug.c
>> ===================================================================
>> --- linux-3.5-rc6.orig/drivers/acpi/acpi_memhotplug.c 2012-07-17 11:20:15.117796971 +0900
>> +++ linux-3.5-rc6/drivers/acpi/acpi_memhotplug.c 2012-07-17 13:36:30.325594022 +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 +453,36 @@ 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;
>> + }
>> + if (node < 0)
>> + node = memory_add_physaddr_to_nid(info->start_addr);
>> +
>> + result = remove_memory(node, info->start_addr, info->length);
>> + 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 2012-07-17 11:20:15.133796772 +0900
>> +++ linux-3.5-rc6/include/linux/memory_hotplug.h 2012-07-17 11:29:41.490716352 +0900
>> @@ -221,6 +221,7 @@ static inline void unlock_memory_hotplug
>> #ifdef CONFIG_MEMORY_HOTREMOVE
>>
>> extern int is_mem_section_removable(unsigned long pfn, unsigned long nr_pages);
>> +extern int remove_memory(int nid, u64 start, u64 size);
>>
>> #else
>> static inline int is_mem_section_removable(unsigned long pfn,
>> @@ -228,6 +229,10 @@ static inline int is_mem_section_removab
>> {
>> return 0;
>> }
>> +static inline int remove_memory(int nid, u64 start, u64 size)
>> +{
>> + return -EBUSY;
>> +}
>> #endif /* CONFIG_MEMORY_HOTREMOVE */
>>
>> extern int mem_online_node(int nid);
>> Index: linux-3.5-rc6/mm/memory_hotplug.c
>> ===================================================================
>> --- linux-3.5-rc6.orig/mm/memory_hotplug.c 2012-07-17 11:20:15.129796821 +0900
>> +++ linux-3.5-rc6/mm/memory_hotplug.c 2012-07-17 13:25:18.952986069 +0900
>> @@ -998,6 +998,28 @@ int offline_memory(u64 start, u64 size)
>> end_pfn = start_pfn + PFN_DOWN(size);
>> return offline_pages(start_pfn, end_pfn, 120 * HZ);
>> }
>> +
>> +int remove_memory(int nid, u64 start, u64 size)
>> +{
>> + int ret = -EBUSY;
>> + lock_memory_hotplug();
>> + /*
>> + * The memory might become online by other task, even if you offine it.
>> + * So we check whether the cpu has been onlined or not.
>> + */
>> + if (!is_memblk_offline(start, size)) {
>> + pr_warn("memory removing [mem %#010llx-%#010llx] failed, "
>> + "because the memmory range is online\n",
>> + start, start + size);
>> + ret = -EAGAIN;
>> + }
>> +
>> + unlock_memory_hotplug();
>> + return ret;
>> +
>> +}
>> +EXPORT_SYMBOL_GPL(remove_memory);
>> +
>> #else
>> int offline_memory(u64 start, u64 size)
>> {
>> Index: linux-3.5-rc6/drivers/base/memory.c
>> ===================================================================
>> --- linux-3.5-rc6.orig/drivers/base/memory.c 2012-07-17 11:20:15.120796934 +0900
>> +++ linux-3.5-rc6/drivers/base/memory.c 2012-07-17 11:20:54.626302995 +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);
>
> This line is wrong. I think you want this:
> end_pfn = start_pfn + PFN_UP(size);

Yes. I'll update it.

>> +
>> + for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
>> + section_nr = pfn_to_section_nr(pfn);
>> + if (!present_section_nr(section_nr));
>
> The ';' should be removed. Otherwise, this function always return true...

Thanks. I'll update it.

Thanks,
Yasuaki Ishimatsu

> Thanks
> Wen Congyang
>
>> + 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 2012-07-17 11:18:00.693477455 +0900
>> +++ linux-3.5-rc6/include/linux/memory.h 2012-07-17 11:20:54.632302919 +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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