[RFC PATCH v2 2/13] memory-hotplug : add physical memory hotplug code to acpi_memory_device_remove

Yasuaki Ishimatsu
2012-07-03T05:54:24Z

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 <rientjes@google.com>
CC: Jiang Liu <liuj97@gmail.com>
CC: Len Brown <len.brown@intel.com>
CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: Paul Mackerras <paulus@samba.org>
CC: Christoph Lameter <cl@linux.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>

---
drivers/acpi/acpi_memhotplug.c | 26 +++++++++++++++++++++++++-
drivers/base/memory.c | 38 ++++++++++++++++++++++++++++++++++++++
include/linux/memory.h | 5 +++++
include/linux/memory_hotplug.h | 1 +
mm/memory_hotplug.c | 8 ++++++++
5 files changed, 77 insertions(+), 1 deletion(-)

Index: linux-3.5-rc4/drivers/acpi/acpi_memhotplug.c
===================================================================
--- linux-3.5-rc4.orig/drivers/acpi/acpi_memhotplug.c 2012-07-03 14:21:49.458374960 +0900
+++ linux-3.5-rc4/drivers/acpi/acpi_memhotplug.c 2012-07-03 14:21:58.329264059 +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);
+ if (result)
+ return result;
+
+ list_del(&info->list);
+ kfree(info);
+ }
+
kfree(mem_device);

return 0;
Index: linux-3.5-rc4/include/linux/memory_hotplug.h
===================================================================
--- linux-3.5-rc4.orig/include/linux/memory_hotplug.h 2012-07-03 14:21:49.471374796 +0900
+++ linux-3.5-rc4/include/linux/memory_hotplug.h 2012-07-03 14:21:58.330264047 +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-rc4/mm/memory_hotplug.c
===================================================================
--- linux-3.5-rc4.orig/mm/memory_hotplug.c 2012-07-03 14:21:49.466374860 +0900
+++ linux-3.5-rc4/mm/memory_hotplug.c 2012-07-03 14:21:58.332264022 +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-rc4/drivers/base/memory.c
===================================================================
--- linux-3.5-rc4.orig/drivers/base/memory.c 2012-07-03 14:21:49.459374948 +0900
+++ linux-3.5-rc4/drivers/base/memory.c 2012-07-03 14:21:58.335263984 +0900
@@ -70,6 +70,44 @@ 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) {
+ kobject_put(&mem->dev.kobj);
+ continue;
+ }
+
+ kobject_put(&mem->dev.kobj);
+ return false;
+ }
+
+ return true;
+}
+EXPORT_SYMBOL(is_memblk_offline);
+
/*
* 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 2012-07-03 14:21:45.998418215 +0900
+++ linux-3.5-rc4/include/linux/memory.h 2012-07-03 14:21:58.340263922 +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 */