[PATCH v3 00/12] memory-hotplug: hot-remove physical memory

[PATCH v3 00/12] memory-hotplug: hot-remove physical memory

[Wen Congyang]

The patch-set was divided from following thread's patch-set.
    https://lkml.org/lkml/2012/9/5/201

The last version of this patchset:
    https://lkml.org/lkml/2012/10/23/213

If you want to know the reason, please read following thread.

https://lkml.org/lkml/2012/10/2/83

The patch-set has only the function of kernel core side for physical
memory hot remove. So if you use the patch, please apply following
patches.

- bug fix for memory hot remove
  https://lkml.org/lkml/2012/10/31/269
  
- acpi framework
  https://lkml.org/lkml/2012/10/26/175

The patches can free/remove the following things:

  - /sys/firmware/memmap/X/{end, start, type} : [PATCH 2/10]
  - mem_section and related sysfs files       : [PATCH 3-4/10]
  - memmap of sparse-vmemmap                  : [PATCH 5-7/10]
  - page table of removed memory              : [RFC PATCH 8/10]
  - node and related sysfs files              : [RFC PATCH 9-10/10]

* [PATCH 2/10] checks whether the memory can be removed or not.

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
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. 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


Changelogs from v2 to v3:
 Patch9: call sync_global_pgds() if pgd is changed
 Patch10: fix a problem int the patch

Changelogs from v1 to v2:
 Patch1: new patch, offline memory twice. 1st iterate: offline every non primary
         memory block. 2nd iterate: offline primary (i.e. first added) memory
         block.

 Patch3: new patch, no logical change, just remove reduntant codes.

 Patch9: merge the patch from wujianguo into this patch. flush tlb on all cpu
         after the pagetable is changed.

 Patch12: new patch, free node_data when a node is offlined

Wen Congyang (6):
  memory-hotplug: try to offline the memory twice to avoid dependence
  memory-hotplug: remove redundant codes
  memory-hotplug: introduce new function arch_remove_memory() for
    removing page table depends on architecture
  memory-hotplug: remove page table of x86_64 architecture
  memory-hotplug: remove sysfs file of node
  memory-hotplug: free node_data when a node is offlined

Yasuaki Ishimatsu (6):
  memory-hotplug: check whether all memory blocks are offlined or not
    when removing memory
  memory-hotplug: remove /sys/firmware/memmap/X sysfs
  memory-hotplug: unregister memory section on SPARSEMEM_VMEMMAP
  memory-hotplug: implement register_page_bootmem_info_section of
    sparse-vmemmap
  memory-hotplug: remove memmap of sparse-vmemmap
  memory-hotplug: memory_hotplug: clear zone when removing the memory

 arch/ia64/mm/discontig.c             |  14 ++
 arch/ia64/mm/init.c                  |  18 ++
 arch/powerpc/mm/init_64.c            |  14 ++
 arch/powerpc/mm/mem.c                |  12 +
 arch/s390/mm/init.c                  |  12 +
 arch/s390/mm/vmem.c                  |  14 ++
 arch/sh/mm/init.c                    |  17 ++
 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                |  12 +
 arch/x86/mm/init_64.c                | 417 +++++++++++++++++++++++++++++++++++
 arch/x86/mm/pageattr.c               |  47 ++--
 drivers/acpi/acpi_memhotplug.c       |   8 +-
 drivers/base/memory.c                |   6 +
 drivers/firmware/memmap.c            |  98 +++++++-
 include/linux/firmware-map.h         |   6 +
 include/linux/memory_hotplug.h       |  15 +-
 include/linux/mm.h                   |   5 +-
 mm/memory_hotplug.c                  | 409 ++++++++++++++++++++++++++++++++--
 mm/sparse.c                          |   5 +-
 21 files changed, 1095 insertions(+), 57 deletions(-)

-- 
1.8.0

[PATCH v3 01/12] memory-hotplug: try to offline the memory twice to avoid dependence

[Wen Congyang]

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, iterate twice to offline the memory.
1st iterate: offline every non primary memory block.
2nd iterate: offline primary (i.e. first added) memory block.

This idea is suggested by KOSAKI Motohiro.

CC: David Rientjes <rientjes@google.com>
CC: Jiang Liu <liuj97@gmail.com>
CC: Len Brown <len.brown@intel.com>
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>
CC: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
---
 mm/memory_hotplug.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 56b758a..600e200 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1019,10 +1019,13 @@ int remove_memory(u64 start, u64 size)
 	unsigned long start_pfn, end_pfn;
 	unsigned long pfn, section_nr;
 	int ret;
+	int return_on_error = 0;
+	int retry = 0;
 
 	start_pfn = PFN_DOWN(start);
 	end_pfn = start_pfn + PFN_DOWN(size);
 
+repeat:
 	for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
 		section_nr = pfn_to_section_nr(pfn);
 		if (!present_section_nr(section_nr))
@@ -1041,14 +1044,23 @@ int remove_memory(u64 start, u64 size)
 
 		ret = offline_memory_block(mem);
 		if (ret) {
-			kobject_put(&mem->dev.kobj);
-			return ret;
+			if (return_on_error) {
+				kobject_put(&mem->dev.kobj);
+				return ret;
+			} else {
+				retry = 1;
+			}
 		}
 	}
 
 	if (mem)
 		kobject_put(&mem->dev.kobj);
 
+	if (retry) {
+		return_on_error = 1;
+		goto repeat;
+	}
+
 	return 0;
 }
 #else
-- 
1.8.0

[PATCH v3 02/12] memory-hotplug: check whether all memory blocks are offlined or not when removing memory

[Wen Congyang]

From: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>

We remove the memory like this:
1. lock memory hotplug
2. offline a memory block
3. unlock memory hotplug
4. repeat 1-3 to offline all memory blocks
5. lock memory hotplug
6. remove memory(TODO)
7. unlock memory hotplug

All memory blocks must be offlined before removing memory. But we don't hold
the lock in the whole operation. So we should check whether all memory blocks
are offlined before step6. Otherwise, kernel maybe panicked.

CC: David Rientjes <rientjes@google.com>
CC: Jiang Liu <liuj97@gmail.com>
CC: Len Brown <len.brown@intel.com>
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: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
---
 drivers/base/memory.c          |  6 ++++++
 include/linux/memory_hotplug.h |  1 +
 mm/memory_hotplug.c            | 47 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 54 insertions(+)

diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index 86c8821..badb025 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -675,6 +675,12 @@ int offline_memory_block(struct memory_block *mem)
 	return ret;
 }
 
+/* return true if the memory block is offlined, otherwise, return false */
+bool is_memblock_offlined(struct memory_block *mem)
+{
+	return mem->state == MEM_OFFLINE;
+}
+
 /*
  * Initialize the sysfs support for memory devices...
  */
diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index 95573ec..38675e9 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -236,6 +236,7 @@ extern int add_memory(int nid, u64 start, u64 size);
 extern int arch_add_memory(int nid, u64 start, u64 size);
 extern int offline_pages(unsigned long start_pfn, unsigned long nr_pages);
 extern int offline_memory_block(struct memory_block *mem);
+extern bool is_memblock_offlined(struct memory_block *mem);
 extern int remove_memory(u64 start, u64 size);
 extern int sparse_add_one_section(struct zone *zone, unsigned long start_pfn,
 								int nr_pages);
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 600e200..f4fdedd 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1061,6 +1061,53 @@ repeat:
 		goto repeat;
 	}
 
+	lock_memory_hotplug();
+
+	/*
+	 * we have offlined all memory blocks like this:
+	 *   1. lock memory hotplug
+	 *   2. offline a memory block
+	 *   3. unlock memory hotplug
+	 *
+	 * repeat step1-3 to offline the memory block. All memory blocks
+	 * must be offlined before removing memory. But we don't hold the
+	 * lock in the whole operation. So we should check whether all
+	 * memory blocks are offlined.
+	 */
+
+	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;
+
+		ret = is_memblock_offlined(mem);
+		if (!ret) {
+			pr_warn("removing memory fails, because memory "
+				"[%#010llx-%#010llx] is onlined\n",
+				PFN_PHYS(section_nr_to_pfn(mem->start_section_nr)),
+				PFN_PHYS(section_nr_to_pfn(mem->end_section_nr + 1)) - 1);
+
+			kobject_put(&mem->dev.kobj);
+			unlock_memory_hotplug();
+			return ret;
+		}
+	}
+
+	if (mem)
+		kobject_put(&mem->dev.kobj);
+	unlock_memory_hotplug();
+
 	return 0;
 }
 #else
-- 
1.8.0

[PATCH v3 03/12] memory-hotplug: remove redundant codes

[Wen Congyang]

offlining memory blocks and checking whether memory blocks are offlined
are very similar. This patch introduces a new function to remove
redundant codes.

CC: David Rientjes <rientjes@google.com>
CC: Jiang Liu <liuj97@gmail.com>
CC: Len Brown <len.brown@intel.com>
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>
CC: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
---
 mm/memory_hotplug.c | 101 ++++++++++++++++++++++++++++------------------------
 1 file changed, 55 insertions(+), 46 deletions(-)

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index f4fdedd..80fc70c 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1012,20 +1012,14 @@ int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
 	return __offline_pages(start_pfn, start_pfn + nr_pages, 120 * HZ);
 }
 
-int remove_memory(u64 start, u64 size)
+static int walk_memory_range(unsigned long start_pfn, unsigned long end_pfn,
+		void *arg, int (*func)(struct memory_block *, void *))
 {
 	struct memory_block *mem = NULL;
 	struct mem_section *section;
-	unsigned long start_pfn, end_pfn;
 	unsigned long pfn, section_nr;
 	int ret;
-	int return_on_error = 0;
-	int retry = 0;
-
-	start_pfn = PFN_DOWN(start);
-	end_pfn = start_pfn + PFN_DOWN(size);
 
-repeat:
 	for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
 		section_nr = pfn_to_section_nr(pfn);
 		if (!present_section_nr(section_nr))
@@ -1042,22 +1036,61 @@ repeat:
 		if (!mem)
 			continue;
 
-		ret = offline_memory_block(mem);
+		ret = func(mem, arg);
 		if (ret) {
-			if (return_on_error) {
-				kobject_put(&mem->dev.kobj);
-				return ret;
-			} else {
-				retry = 1;
-			}
+			kobject_put(&mem->dev.kobj);
+			return ret;
 		}
 	}
 
 	if (mem)
 		kobject_put(&mem->dev.kobj);
 
-	if (retry) {
-		return_on_error = 1;
+	return 0;
+}
+
+static int offline_memory_block_cb(struct memory_block *mem, void *arg)
+{
+	int *ret = arg;
+	int error = offline_memory_block(mem);
+
+	if (error != 0 && *ret == 0)
+		*ret = error;
+
+	return 0;
+}
+
+static int is_memblock_offlined_cb(struct memory_block *mem, void *arg)
+{
+	int ret = !is_memblock_offlined(mem);
+
+	if (unlikely(ret))
+		pr_warn("removing memory fails, because memory "
+			"[%#010llx-%#010llx] is onlined\n",
+			PFN_PHYS(section_nr_to_pfn(mem->start_section_nr)),
+			PFN_PHYS(section_nr_to_pfn(mem->end_section_nr + 1))-1);
+
+	return ret;
+}
+
+int remove_memory(u64 start, u64 size)
+{
+	unsigned long start_pfn, end_pfn;
+	int ret = 0;
+	int retry = 1;
+
+	start_pfn = PFN_DOWN(start);
+	end_pfn = start_pfn + PFN_DOWN(size);
+
+repeat:
+	walk_memory_range(start_pfn, end_pfn, &ret,
+			  offline_memory_block_cb);
+	if (ret) {
+		if (!retry)
+			return ret;
+
+		retry = 0;
+		ret = 0;
 		goto repeat;
 	}
 
@@ -1075,37 +1108,13 @@ repeat:
 	 * memory blocks are offlined.
 	 */
 
-	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;
-
-		ret = is_memblock_offlined(mem);
-		if (!ret) {
-			pr_warn("removing memory fails, because memory "
-				"[%#010llx-%#010llx] is onlined\n",
-				PFN_PHYS(section_nr_to_pfn(mem->start_section_nr)),
-				PFN_PHYS(section_nr_to_pfn(mem->end_section_nr + 1)) - 1);
-
-			kobject_put(&mem->dev.kobj);
-			unlock_memory_hotplug();
-			return ret;
-		}
+	ret = walk_memory_range(start_pfn, end_pfn, NULL,
+				is_memblock_offlined_cb);
+	if (ret) {
+		unlock_memory_hotplug();
+		return ret;
 	}
 
-	if (mem)
-		kobject_put(&mem->dev.kobj);
 	unlock_memory_hotplug();
 
 	return 0;
-- 
1.8.0

[PATCH v3 04/12] memory-hotplug: remove /sys/firmware/memmap/X sysfs

[Wen Congyang]

From: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>

When (hot)adding memory into system, /sys/firmware/memmap/X/{end, start, type}
sysfs files are created. But there is no code to remove these files. The patch
implements the function to remove them.

Note: The code does not free firmware_map_entry which is allocated by bootmem.
      So the patch makes memory leak. But I think the memory leak size is
      very samll. And it does not affect the system.

CC: David Rientjes <rientjes@google.com>
CC: Jiang Liu <liuj97@gmail.com>
CC: Len Brown <len.brown@intel.com>
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: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
---
 drivers/firmware/memmap.c    | 98 +++++++++++++++++++++++++++++++++++++++++++-
 include/linux/firmware-map.h |  6 +++
 mm/memory_hotplug.c          |  5 ++-
 3 files changed, 106 insertions(+), 3 deletions(-)

diff --git a/drivers/firmware/memmap.c b/drivers/firmware/memmap.c
index 90723e6..49be12a 100644
--- a/drivers/firmware/memmap.c
+++ b/drivers/firmware/memmap.c
@@ -21,6 +21,7 @@
 #include <linux/types.h>
 #include <linux/bootmem.h>
 #include <linux/slab.h>
+#include <linux/mm.h>
 
 /*
  * Data types ------------------------------------------------------------------
@@ -41,6 +42,7 @@ struct firmware_map_entry {
 	const char		*type;	/* type of the memory range */
 	struct list_head	list;	/* entry for the linked list */
 	struct kobject		kobj;   /* kobject for each entry */
+	unsigned int		bootmem:1; /* allocated from bootmem */
 };
 
 /*
@@ -79,7 +81,26 @@ static const struct sysfs_ops memmap_attr_ops = {
 	.show = memmap_attr_show,
 };
 
+
+static inline struct firmware_map_entry *
+to_memmap_entry(struct kobject *kobj)
+{
+	return container_of(kobj, struct firmware_map_entry, kobj);
+}
+
+static void release_firmware_map_entry(struct kobject *kobj)
+{
+	struct firmware_map_entry *entry = to_memmap_entry(kobj);
+
+	if (entry->bootmem)
+		/* There is no way to free memory allocated from bootmem */
+		return;
+
+	kfree(entry);
+}
+
 static struct kobj_type memmap_ktype = {
+	.release	= release_firmware_map_entry,
 	.sysfs_ops	= &memmap_attr_ops,
 	.default_attrs	= def_attrs,
 };
@@ -94,6 +115,7 @@ static struct kobj_type memmap_ktype = {
  * in firmware initialisation code in one single thread of execution.
  */
 static LIST_HEAD(map_entries);
+static DEFINE_SPINLOCK(map_entries_lock);
 
 /**
  * firmware_map_add_entry() - Does the real work to add a firmware memmap entry.
@@ -118,11 +140,25 @@ static int firmware_map_add_entry(u64 start, u64 end,
 	INIT_LIST_HEAD(&entry->list);
 	kobject_init(&entry->kobj, &memmap_ktype);
 
+	spin_lock(&map_entries_lock);
 	list_add_tail(&entry->list, &map_entries);
+	spin_unlock(&map_entries_lock);
 
 	return 0;
 }
 
+/**
+ * firmware_map_remove_entry() - Does the real work to remove a firmware
+ * memmap entry.
+ * @entry: removed entry.
+ **/
+static inline void firmware_map_remove_entry(struct firmware_map_entry *entry)
+{
+	spin_lock(&map_entries_lock);
+	list_del(&entry->list);
+	spin_unlock(&map_entries_lock);
+}
+
 /*
  * Add memmap entry on sysfs
  */
@@ -144,6 +180,35 @@ static int add_sysfs_fw_map_entry(struct firmware_map_entry *entry)
 	return 0;
 }
 
+/*
+ * Remove memmap entry on sysfs
+ */
+static inline void remove_sysfs_fw_map_entry(struct firmware_map_entry *entry)
+{
+	kobject_put(&entry->kobj);
+}
+
+/*
+ * Search memmap entry
+ */
+
+static struct firmware_map_entry * __meminit
+firmware_map_find_entry(u64 start, u64 end, const char *type)
+{
+	struct firmware_map_entry *entry;
+
+	spin_lock(&map_entries_lock);
+	list_for_each_entry(entry, &map_entries, list)
+		if ((entry->start == start) && (entry->end == end) &&
+		    (!strcmp(entry->type, type))) {
+			spin_unlock(&map_entries_lock);
+			return entry;
+		}
+
+	spin_unlock(&map_entries_lock);
+	return NULL;
+}
+
 /**
  * firmware_map_add_hotplug() - Adds a firmware mapping entry when we do
  * memory hotplug.
@@ -193,9 +258,36 @@ int __init firmware_map_add_early(u64 start, u64 end, const char *type)
 	if (WARN_ON(!entry))
 		return -ENOMEM;
 
+	entry->bootmem = 1;
 	return firmware_map_add_entry(start, end, type, entry);
 }
 
+/**
+ * firmware_map_remove() - remove a firmware mapping entry
+ * @start: Start of the memory range.
+ * @end:   End of the memory range.
+ * @type:  Type of the memory range.
+ *
+ * removes a firmware mapping entry.
+ *
+ * Returns 0 on success, or -EINVAL if no entry.
+ **/
+int __meminit firmware_map_remove(u64 start, u64 end, const char *type)
+{
+	struct firmware_map_entry *entry;
+
+	entry = firmware_map_find_entry(start, end - 1, type);
+	if (!entry)
+		return -EINVAL;
+
+	firmware_map_remove_entry(entry);
+
+	/* remove the memmap entry */
+	remove_sysfs_fw_map_entry(entry);
+
+	return 0;
+}
+
 /*
  * Sysfs functions -------------------------------------------------------------
  */
@@ -217,8 +309,10 @@ static ssize_t type_show(struct firmware_map_entry *entry, char *buf)
 	return snprintf(buf, PAGE_SIZE, "%s\n", entry->type);
 }
 
-#define to_memmap_attr(_attr) container_of(_attr, struct memmap_attribute, attr)
-#define to_memmap_entry(obj) container_of(obj, struct firmware_map_entry, kobj)
+static inline struct memmap_attribute *to_memmap_attr(struct attribute *attr)
+{
+	return container_of(attr, struct memmap_attribute, attr);
+}
 
 static ssize_t memmap_attr_show(struct kobject *kobj,
 				struct attribute *attr, char *buf)
diff --git a/include/linux/firmware-map.h b/include/linux/firmware-map.h
index 43fe52fc..71d4fa7 100644
--- a/include/linux/firmware-map.h
+++ b/include/linux/firmware-map.h
@@ -25,6 +25,7 @@
 
 int firmware_map_add_early(u64 start, u64 end, const char *type);
 int firmware_map_add_hotplug(u64 start, u64 end, const char *type);
+int firmware_map_remove(u64 start, u64 end, const char *type);
 
 #else /* CONFIG_FIRMWARE_MEMMAP */
 
@@ -38,6 +39,11 @@ static inline int firmware_map_add_hotplug(u64 start, u64 end, const char *type)
 	return 0;
 }
 
+static inline int firmware_map_remove(u64 start, u64 end, const char *type)
+{
+	return 0;
+}
+
 #endif /* CONFIG_FIRMWARE_MEMMAP */
 
 #endif /* _LINUX_FIRMWARE_MAP_H */
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 80fc70c..050ddb0 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1073,7 +1073,7 @@ static int is_memblock_offlined_cb(struct memory_block *mem, void *arg)
 	return ret;
 }
 
-int remove_memory(u64 start, u64 size)
+int __ref remove_memory(u64 start, u64 size)
 {
 	unsigned long start_pfn, end_pfn;
 	int ret = 0;
@@ -1115,6 +1115,9 @@ repeat:
 		return ret;
 	}
 
+	/* remove memmap entry */
+	firmware_map_remove(start, start + size, "System RAM");
+
 	unlock_memory_hotplug();
 
 	return 0;
-- 
1.8.0

[PATCH v3 05/12] memory-hotplug: introduce new function arch_remove_memory() for removing page table depends on architecture

[Wen Congyang]

For removing memory, we need to remove page table. But it depends
on architecture. So the patch introduce arch_remove_memory() for
removing page table. Now it only calls __remove_pages().

Note: __remove_pages() for some archtecuture is not implemented
      (I don't know how to implement it for s390).

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>
CC: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
---
 arch/ia64/mm/init.c            | 18 ++++++++++++++++++
 arch/powerpc/mm/mem.c          | 12 ++++++++++++
 arch/s390/mm/init.c            | 12 ++++++++++++
 arch/sh/mm/init.c              | 17 +++++++++++++++++
 arch/tile/mm/init.c            |  8 ++++++++
 arch/x86/mm/init_32.c          | 12 ++++++++++++
 arch/x86/mm/init_64.c          | 15 +++++++++++++++
 include/linux/memory_hotplug.h |  1 +
 mm/memory_hotplug.c            |  2 ++
 9 files changed, 97 insertions(+)

diff --git a/arch/ia64/mm/init.c b/arch/ia64/mm/init.c
index acd5b68..1d36ba2 100644
--- a/arch/ia64/mm/init.c
+++ b/arch/ia64/mm/init.c
@@ -690,6 +690,24 @@ int arch_add_memory(int nid, u64 start, u64 size)
 
 	return ret;
 }
+
+#ifdef CONFIG_MEMORY_HOTREMOVE
+int arch_remove_memory(u64 start, u64 size)
+{
+	unsigned long start_pfn = start >> PAGE_SHIFT;
+	unsigned long nr_pages = size >> PAGE_SHIFT;
+	struct zone *zone;
+	int ret;
+
+	zone = page_zone(pfn_to_page(start_pfn));
+	ret = __remove_pages(zone, start_pfn, nr_pages);
+	if (ret)
+		pr_warn("%s: Problem encountered in __remove_pages() as"
+			" ret=%d\n", __func__,  ret);
+
+	return ret;
+}
+#endif
 #endif
 
 /*
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index 0dba506..09c6451 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -133,6 +133,18 @@ int arch_add_memory(int nid, u64 start, u64 size)
 
 	return __add_pages(nid, zone, start_pfn, nr_pages);
 }
+
+#ifdef CONFIG_MEMORY_HOTREMOVE
+int arch_remove_memory(u64 start, u64 size)
+{
+	unsigned long start_pfn = start >> PAGE_SHIFT;
+	unsigned long nr_pages = size >> PAGE_SHIFT;
+	struct zone *zone;
+
+	zone = page_zone(pfn_to_page(start_pfn));
+	return __remove_pages(zone, start_pfn, nr_pages);
+}
+#endif
 #endif /* CONFIG_MEMORY_HOTPLUG */
 
 /*
diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index 81e596c..b565190 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -257,4 +257,16 @@ int arch_add_memory(int nid, u64 start, u64 size)
 		vmem_remove_mapping(start, size);
 	return rc;
 }
+
+#ifdef CONFIG_MEMORY_HOTREMOVE
+int arch_remove_memory(u64 start, u64 size)
+{
+	/*
+	 * There is no hardware or firmware interface which could trigger a
+	 * hot memory remove on s390. So there is nothing that needs to be
+	 * implemented.
+	 */
+	return -EBUSY;
+}
+#endif
 #endif /* CONFIG_MEMORY_HOTPLUG */
diff --git a/arch/sh/mm/init.c b/arch/sh/mm/init.c
index 82cc576..1057940 100644
--- a/arch/sh/mm/init.c
+++ b/arch/sh/mm/init.c
@@ -558,4 +558,21 @@ int memory_add_physaddr_to_nid(u64 addr)
 EXPORT_SYMBOL_GPL(memory_add_physaddr_to_nid);
 #endif
 
+#ifdef CONFIG_MEMORY_HOTREMOVE
+int arch_remove_memory(u64 start, u64 size)
+{
+	unsigned long start_pfn = start >> PAGE_SHIFT;
+	unsigned long nr_pages = size >> PAGE_SHIFT;
+	struct zone *zone;
+	int ret;
+
+	zone = page_zone(pfn_to_page(start_pfn));
+	ret = __remove_pages(zone, start_pfn, nr_pages);
+	if (unlikely(ret))
+		pr_warn("%s: Failed, __remove_pages() == %d\n", __func__,
+			ret);
+
+	return ret;
+}
+#endif
 #endif /* CONFIG_MEMORY_HOTPLUG */
diff --git a/arch/tile/mm/init.c b/arch/tile/mm/init.c
index ef29d6c..2749515 100644
--- a/arch/tile/mm/init.c
+++ b/arch/tile/mm/init.c
@@ -935,6 +935,14 @@ int remove_memory(u64 start, u64 size)
 {
 	return -EINVAL;
 }
+
+#ifdef CONFIG_MEMORY_HOTREMOVE
+int arch_remove_memory(u64 start, u64 size)
+{
+	/* TODO */
+	return -EBUSY;
+}
+#endif
 #endif
 
 struct kmem_cache *pgd_cache;
diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
index 11a5800..b19eba4 100644
--- a/arch/x86/mm/init_32.c
+++ b/arch/x86/mm/init_32.c
@@ -839,6 +839,18 @@ int arch_add_memory(int nid, u64 start, u64 size)
 
 	return __add_pages(nid, zone, start_pfn, nr_pages);
 }
+
+#ifdef CONFIG_MEMORY_HOTREMOVE
+int arch_remove_memory(u64 start, u64 size)
+{
+	unsigned long start_pfn = start >> PAGE_SHIFT;
+	unsigned long nr_pages = size >> PAGE_SHIFT;
+	struct zone *zone;
+
+	zone = page_zone(pfn_to_page(start_pfn));
+	return __remove_pages(zone, start_pfn, nr_pages);
+}
+#endif
 #endif
 
 /*
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 3baff25..5675335 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -680,6 +680,21 @@ int arch_add_memory(int nid, u64 start, u64 size)
 }
 EXPORT_SYMBOL_GPL(arch_add_memory);
 
+#ifdef CONFIG_MEMORY_HOTREMOVE
+int __ref arch_remove_memory(u64 start, u64 size)
+{
+	unsigned long start_pfn = start >> PAGE_SHIFT;
+	unsigned long nr_pages = size >> PAGE_SHIFT;
+	struct zone *zone;
+	int ret;
+
+	zone = page_zone(pfn_to_page(start_pfn));
+	ret = __remove_pages(zone, start_pfn, nr_pages);
+	WARN_ON_ONCE(ret);
+
+	return ret;
+}
+#endif
 #endif /* CONFIG_MEMORY_HOTPLUG */
 
 static struct kcore_list kcore_vsyscall;
diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index 38675e9..191b2d9 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -85,6 +85,7 @@ extern void __online_page_free(struct page *page);
 
 #ifdef CONFIG_MEMORY_HOTREMOVE
 extern bool is_pageblock_removable_nolock(struct page *page);
+extern int arch_remove_memory(u64 start, u64 size);
 #endif /* CONFIG_MEMORY_HOTREMOVE */
 
 /* reasonably generic interface to expand the physical pages in a zone  */
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 050ddb0..ca07433 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1118,6 +1118,8 @@ repeat:
 	/* remove memmap entry */
 	firmware_map_remove(start, start + size, "System RAM");
 
+	arch_remove_memory(start, size);
+
 	unlock_memory_hotplug();
 
 	return 0;
-- 
1.8.0

[PATCH v3 06/12] memory-hotplug: unregister memory section on SPARSEMEM_VMEMMAP

[Wen Congyang]

From: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>

Currently __remove_section for SPARSEMEM_VMEMMAP does nothing. But even if
we use SPARSEMEM_VMEMMAP, we can unregister the memory_section.

So the patch add unregister_memory_section() into __remove_section().

CC: David Rientjes <rientjes@google.com>
CC: Jiang Liu <liuj97@gmail.com>
CC: Len Brown <len.brown@intel.com>
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>
CC: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
---
 mm/memory_hotplug.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index ca07433..66a79a7 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -286,11 +286,14 @@ static int __meminit __add_section(int nid, struct zone *zone,
 #ifdef CONFIG_SPARSEMEM_VMEMMAP
 static int __remove_section(struct zone *zone, struct mem_section *ms)
 {
-	/*
-	 * XXX: Freeing memmap with vmemmap is not implement yet.
-	 *      This should be removed later.
-	 */
-	return -EBUSY;
+	int ret = -EINVAL;
+
+	if (!valid_section(ms))
+		return ret;
+
+	ret = unregister_memory_section(ms);
+
+	return ret;
 }
 #else
 static int __remove_section(struct zone *zone, struct mem_section *ms)
-- 
1.8.0

Re: [PATCH v3 06/12] memory-hotplug: unregister memory section on SPARSEMEM_VMEMMAP

[Jaegeuk Hanse]

On 11/01/2012 05:44 PM, Wen Congyang wrote:
> From: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
>
> Currently __remove_section for SPARSEMEM_VMEMMAP does nothing. But even if
> we use SPARSEMEM_VMEMMAP, we can unregister the memory_section.
>
> So the patch add unregister_memory_section() into __remove_section().

Hi Yasuaki,

In order to review this patch, I should dig sparse memory codes in 
advance. But I have some confuse of codes. Why need encode/decode mem 
map instead of set mem_map to ms->section_mem_map directly?

Regards,
Jaegeuk

>
> CC: David Rientjes <rientjes@google.com>
> CC: Jiang Liu <liuj97@gmail.com>
> CC: Len Brown <len.brown@intel.com>
> 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>
> CC: Wen Congyang <wency@cn.fujitsu.com>
> Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
> ---
>   mm/memory_hotplug.c | 13 ++++++++-----
>   1 file changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index ca07433..66a79a7 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -286,11 +286,14 @@ static int __meminit __add_section(int nid, struct zone *zone,
>   #ifdef CONFIG_SPARSEMEM_VMEMMAP
>   static int __remove_section(struct zone *zone, struct mem_section *ms)
>   {
> -	/*
> -	 * XXX: Freeing memmap with vmemmap is not implement yet.
> -	 *      This should be removed later.
> -	 */
> -	return -EBUSY;
> +	int ret = -EINVAL;
> +
> +	if (!valid_section(ms))
> +		return ret;
> +
> +	ret = unregister_memory_section(ms);
> +
> +	return ret;
>   }
>   #else
>   static int __remove_section(struct zone *zone, struct mem_section *ms)

Re: [PATCH v3 06/12] memory-hotplug: unregister memory section on SPARSEMEM_VMEMMAP

[Wen Congyang]

At 11/20/2012 02:22 PM, Jaegeuk Hanse Wrote:
> On 11/01/2012 05:44 PM, Wen Congyang wrote:
>> From: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
>>
>> Currently __remove_section for SPARSEMEM_VMEMMAP does nothing. But
>> even if
>> we use SPARSEMEM_VMEMMAP, we can unregister the memory_section.
>>
>> So the patch add unregister_memory_section() into __remove_section().
> 
> Hi Yasuaki,
> 
> In order to review this patch, I should dig sparse memory codes in
> advance. But I have some confuse of codes. Why need encode/decode mem
> map instead of set mem_map to ms->section_mem_map directly?

The memmap is aligned, and the low bits are zero. We store some information
in these bits. So we need to encode/decode memmap here.

Thanks
Wen Congyang

> 
> Regards,
> Jaegeuk
> 
>>
>> CC: David Rientjes <rientjes@google.com>
>> CC: Jiang Liu <liuj97@gmail.com>
>> CC: Len Brown <len.brown@intel.com>
>> 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>
>> CC: Wen Congyang <wency@cn.fujitsu.com>
>> Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
>> ---
>>   mm/memory_hotplug.c | 13 ++++++++-----
>>   1 file changed, 8 insertions(+), 5 deletions(-)
>>
>> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
>> index ca07433..66a79a7 100644
>> --- a/mm/memory_hotplug.c
>> +++ b/mm/memory_hotplug.c
>> @@ -286,11 +286,14 @@ static int __meminit __add_section(int nid,
>> struct zone *zone,
>>   #ifdef CONFIG_SPARSEMEM_VMEMMAP
>>   static int __remove_section(struct zone *zone, struct mem_section *ms)
>>   {
>> -    /*
>> -     * XXX: Freeing memmap with vmemmap is not implement yet.
>> -     *      This should be removed later.
>> -     */
>> -    return -EBUSY;
>> +    int ret = -EINVAL;
>> +
>> +    if (!valid_section(ms))
>> +        return ret;
>> +
>> +    ret = unregister_memory_section(ms);
>> +
>> +    return ret;
>>   }
>>   #else
>>   static int __remove_section(struct zone *zone, struct mem_section *ms)
> 
> 

Re: [PATCH v3 06/12] memory-hotplug: unregister memory section on SPARSEMEM_VMEMMAP

[Jaegeuk Hanse]

On 11/20/2012 02:55 PM, Wen Congyang wrote:
> At 11/20/2012 02:22 PM, Jaegeuk Hanse Wrote:
>> On 11/01/2012 05:44 PM, Wen Congyang wrote:
>>> From: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
>>>
>>> Currently __remove_section for SPARSEMEM_VMEMMAP does nothing. But
>>> even if
>>> we use SPARSEMEM_VMEMMAP, we can unregister the memory_section.
>>>
>>> So the patch add unregister_memory_section() into __remove_section().
>> Hi Yasuaki,
>>
>> In order to review this patch, I should dig sparse memory codes in
>> advance. But I have some confuse of codes. Why need encode/decode mem
>> map instead of set mem_map to ms->section_mem_map directly?
> The memmap is aligned, and the low bits are zero. We store some information
> in these bits. So we need to encode/decode memmap here.

Hi Congyang,

Thanks for you reponse. But I mean why return (unsigned long)(mem_map - 
(section_nr_to_pfn(pnum))); in function sparse_encode_mem_map, and then 
return ((struct page *)coded_mem_map) + section_nr_to_pfn(pnum); in 
funtion sparse_decode_mem_map instead of just store mem_map in 
ms->section_mep_map directly.

Regards,
Jaegeuk

>
> Thanks
> Wen Congyang
>
>> Regards,
>> Jaegeuk
>>
>>> CC: David Rientjes <rientjes@google.com>
>>> CC: Jiang Liu <liuj97@gmail.com>
>>> CC: Len Brown <len.brown@intel.com>
>>> 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>
>>> CC: Wen Congyang <wency@cn.fujitsu.com>
>>> Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
>>> ---
>>>    mm/memory_hotplug.c | 13 ++++++++-----
>>>    1 file changed, 8 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
>>> index ca07433..66a79a7 100644
>>> --- a/mm/memory_hotplug.c
>>> +++ b/mm/memory_hotplug.c
>>> @@ -286,11 +286,14 @@ static int __meminit __add_section(int nid,
>>> struct zone *zone,
>>>    #ifdef CONFIG_SPARSEMEM_VMEMMAP
>>>    static int __remove_section(struct zone *zone, struct mem_section *ms)
>>>    {
>>> -    /*
>>> -     * XXX: Freeing memmap with vmemmap is not implement yet.
>>> -     *      This should be removed later.
>>> -     */
>>> -    return -EBUSY;
>>> +    int ret = -EINVAL;
>>> +
>>> +    if (!valid_section(ms))
>>> +        return ret;
>>> +
>>> +    ret = unregister_memory_section(ms);
>>> +
>>> +    return ret;
>>>    }
>>>    #else
>>>    static int __remove_section(struct zone *zone, struct mem_section *ms)
>>

Re: [PATCH v3 06/12] memory-hotplug: unregister memory section on SPARSEMEM_VMEMMAP

[Wen Congyang]

At 11/20/2012 02:58 PM, Jaegeuk Hanse Wrote:
> On 11/20/2012 02:55 PM, Wen Congyang wrote:
>> At 11/20/2012 02:22 PM, Jaegeuk Hanse Wrote:
>>> On 11/01/2012 05:44 PM, Wen Congyang wrote:
>>>> From: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
>>>>
>>>> Currently __remove_section for SPARSEMEM_VMEMMAP does nothing. But
>>>> even if
>>>> we use SPARSEMEM_VMEMMAP, we can unregister the memory_section.
>>>>
>>>> So the patch add unregister_memory_section() into __remove_section().
>>> Hi Yasuaki,
>>>
>>> In order to review this patch, I should dig sparse memory codes in
>>> advance. But I have some confuse of codes. Why need encode/decode mem
>>> map instead of set mem_map to ms->section_mem_map directly?
>> The memmap is aligned, and the low bits are zero. We store some
>> information
>> in these bits. So we need to encode/decode memmap here.
> 
> Hi Congyang,
> 
> Thanks for you reponse. But I mean why return (unsigned long)(mem_map -
> (section_nr_to_pfn(pnum))); in function sparse_encode_mem_map, and then
> return ((struct page *)coded_mem_map) + section_nr_to_pfn(pnum); in
> funtion sparse_decode_mem_map instead of just store mem_map in
> ms->section_mep_map directly.

I don't know why. I try to find the reason, but I don't find any
place to use the pfn stored in the mem_map except in the decode
function. Maybe the designer doesn't want us to access the mem_map
directly.

Thanks
Wen Congyang

> 
> Regards,
> Jaegeuk
> 
>>
>> Thanks
>> Wen Congyang
>>
>>> Regards,
>>> Jaegeuk
>>>
>>>> CC: David Rientjes <rientjes@google.com>
>>>> CC: Jiang Liu <liuj97@gmail.com>
>>>> CC: Len Brown <len.brown@intel.com>
>>>> 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>
>>>> CC: Wen Congyang <wency@cn.fujitsu.com>
>>>> Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
>>>> ---
>>>>    mm/memory_hotplug.c | 13 ++++++++-----
>>>>    1 file changed, 8 insertions(+), 5 deletions(-)
>>>>
>>>> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
>>>> index ca07433..66a79a7 100644
>>>> --- a/mm/memory_hotplug.c
>>>> +++ b/mm/memory_hotplug.c
>>>> @@ -286,11 +286,14 @@ static int __meminit __add_section(int nid,
>>>> struct zone *zone,
>>>>    #ifdef CONFIG_SPARSEMEM_VMEMMAP
>>>>    static int __remove_section(struct zone *zone, struct mem_section
>>>> *ms)
>>>>    {
>>>> -    /*
>>>> -     * XXX: Freeing memmap with vmemmap is not implement yet.
>>>> -     *      This should be removed later.
>>>> -     */
>>>> -    return -EBUSY;
>>>> +    int ret = -EINVAL;
>>>> +
>>>> +    if (!valid_section(ms))
>>>> +        return ret;
>>>> +
>>>> +    ret = unregister_memory_section(ms);
>>>> +
>>>> +    return ret;
>>>>    }
>>>>    #else
>>>>    static int __remove_section(struct zone *zone, struct mem_section
>>>> *ms)
>>>
> 
> 

Re: [PATCH v3 06/12] memory-hotplug: unregister memory section on SPARSEMEM_VMEMMAP

[Jaegeuk Hanse]

On 11/20/2012 05:37 PM, Wen Congyang wrote:
> At 11/20/2012 02:58 PM, Jaegeuk Hanse Wrote:
>> On 11/20/2012 02:55 PM, Wen Congyang wrote:
>>> At 11/20/2012 02:22 PM, Jaegeuk Hanse Wrote:
>>>> On 11/01/2012 05:44 PM, Wen Congyang wrote:
>>>>> From: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
>>>>>
>>>>> Currently __remove_section for SPARSEMEM_VMEMMAP does nothing. But
>>>>> even if
>>>>> we use SPARSEMEM_VMEMMAP, we can unregister the memory_section.
>>>>>
>>>>> So the patch add unregister_memory_section() into __remove_section().
>>>> Hi Yasuaki,
>>>>
>>>> In order to review this patch, I should dig sparse memory codes in
>>>> advance. But I have some confuse of codes. Why need encode/decode mem
>>>> map instead of set mem_map to ms->section_mem_map directly?
>>> The memmap is aligned, and the low bits are zero. We store some
>>> information
>>> in these bits. So we need to encode/decode memmap here.
>> Hi Congyang,
>>
>> Thanks for you reponse. But I mean why return (unsigned long)(mem_map -
>> (section_nr_to_pfn(pnum))); in function sparse_encode_mem_map, and then
>> return ((struct page *)coded_mem_map) + section_nr_to_pfn(pnum); in
>> funtion sparse_decode_mem_map instead of just store mem_map in
>> ms->section_mep_map directly.
> I don't know why. I try to find the reason, but I don't find any
> place to use the pfn stored in the mem_map except in the decode
> function. Maybe the designer doesn't want us to access the mem_map
> directly.

It seems that mem_map is per node, but pfn is real pfn.
you can check __page_to_pfn.

>
> Thanks
> Wen Congyang
>
>> Regards,
>> Jaegeuk
>>
>>> Thanks
>>> Wen Congyang
>>>
>>>> Regards,
>>>> Jaegeuk
>>>>
>>>>> CC: David Rientjes <rientjes@google.com>
>>>>> CC: Jiang Liu <liuj97@gmail.com>
>>>>> CC: Len Brown <len.brown@intel.com>
>>>>> 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>
>>>>> CC: Wen Congyang <wency@cn.fujitsu.com>
>>>>> Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
>>>>> ---
>>>>>     mm/memory_hotplug.c | 13 ++++++++-----
>>>>>     1 file changed, 8 insertions(+), 5 deletions(-)
>>>>>
>>>>> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
>>>>> index ca07433..66a79a7 100644
>>>>> --- a/mm/memory_hotplug.c
>>>>> +++ b/mm/memory_hotplug.c
>>>>> @@ -286,11 +286,14 @@ static int __meminit __add_section(int nid,
>>>>> struct zone *zone,
>>>>>     #ifdef CONFIG_SPARSEMEM_VMEMMAP
>>>>>     static int __remove_section(struct zone *zone, struct mem_section
>>>>> *ms)
>>>>>     {
>>>>> -    /*
>>>>> -     * XXX: Freeing memmap with vmemmap is not implement yet.
>>>>> -     *      This should be removed later.
>>>>> -     */
>>>>> -    return -EBUSY;
>>>>> +    int ret = -EINVAL;
>>>>> +
>>>>> +    if (!valid_section(ms))
>>>>> +        return ret;
>>>>> +
>>>>> +    ret = unregister_memory_section(ms);
>>>>> +
>>>>> +    return ret;
>>>>>     }
>>>>>     #else
>>>>>     static int __remove_section(struct zone *zone, struct mem_section
>>>>> *ms)
>>

Re: [PATCH v3 06/12] memory-hotplug: unregister memory section on SPARSEMEM_VMEMMAP

[Jaegeuk Hanse]

On 11/01/2012 05:44 PM, Wen Congyang wrote:
> From: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
>
> Currently __remove_section for SPARSEMEM_VMEMMAP does nothing. But even if
> we use SPARSEMEM_VMEMMAP, we can unregister the memory_section.
>
> So the patch add unregister_memory_section() into __remove_section().

Hi Yasuaki,

I have a question about these sparse vmemmap memory related patches. Hot 
add memory need allocated vmemmap pages, but this time is allocated by 
buddy system. How can gurantee virtual address is continuous to the 
address allocated before? If not continuous, page_to_pfn and pfn_to_page 
can't work correctly.

Regards,
Jaegeuk

>
> CC: David Rientjes <rientjes@google.com>
> CC: Jiang Liu <liuj97@gmail.com>
> CC: Len Brown <len.brown@intel.com>
> 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>
> CC: Wen Congyang <wency@cn.fujitsu.com>
> Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
> ---
>   mm/memory_hotplug.c | 13 ++++++++-----
>   1 file changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index ca07433..66a79a7 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -286,11 +286,14 @@ static int __meminit __add_section(int nid, struct zone *zone,
>   #ifdef CONFIG_SPARSEMEM_VMEMMAP
>   static int __remove_section(struct zone *zone, struct mem_section *ms)
>   {
> -	/*
> -	 * XXX: Freeing memmap with vmemmap is not implement yet.
> -	 *      This should be removed later.
> -	 */
> -	return -EBUSY;
> +	int ret = -EINVAL;
> +
> +	if (!valid_section(ms))
> +		return ret;
> +
> +	ret = unregister_memory_section(ms);
> +
> +	return ret;
>   }
>   #else
>   static int __remove_section(struct zone *zone, struct mem_section *ms)

Re: [PATCH v3 06/12] memory-hotplug: unregister memory section on SPARSEMEM_VMEMMAP

[Wen Congyang]

At 11/20/2012 07:16 PM, Jaegeuk Hanse Wrote:
> On 11/01/2012 05:44 PM, Wen Congyang wrote:
>> From: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
>>
>> Currently __remove_section for SPARSEMEM_VMEMMAP does nothing. But
>> even if
>> we use SPARSEMEM_VMEMMAP, we can unregister the memory_section.
>>
>> So the patch add unregister_memory_section() into __remove_section().
> 
> Hi Yasuaki,
> 
> I have a question about these sparse vmemmap memory related patches. Hot
> add memory need allocated vmemmap pages, but this time is allocated by
> buddy system. How can gurantee virtual address is continuous to the
> address allocated before? If not continuous, page_to_pfn and pfn_to_page
> can't work correctly.

vmemmap has its virtual address range:
ffffea0000000000 - ffffeaffffffffff (=40 bits) virtual memory map (1TB)

We allocate memory from buddy system to store struct page, and its virtual
address isn't in this range. So we should update the page table:

kmalloc_section_memmap()
    sparse_mem_map_populate()
        pfn_to_page() // get the virtual address in the vmemmap range
        vmemmap_populate() // we update page table here

When we use vmemmap, page_to_pfn() always returns address in the vmemmap
range, not the address that kmalloc() returns. So the virtual address
is continuous.

Thanks
Wen Congyang
> 
> Regards,
> Jaegeuk
> 
>>
>> CC: David Rientjes <rientjes@google.com>
>> CC: Jiang Liu <liuj97@gmail.com>
>> CC: Len Brown <len.brown@intel.com>
>> 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>
>> CC: Wen Congyang <wency@cn.fujitsu.com>
>> Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
>> ---
>>   mm/memory_hotplug.c | 13 ++++++++-----
>>   1 file changed, 8 insertions(+), 5 deletions(-)
>>
>> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
>> index ca07433..66a79a7 100644
>> --- a/mm/memory_hotplug.c
>> +++ b/mm/memory_hotplug.c
>> @@ -286,11 +286,14 @@ static int __meminit __add_section(int nid,
>> struct zone *zone,
>>   #ifdef CONFIG_SPARSEMEM_VMEMMAP
>>   static int __remove_section(struct zone *zone, struct mem_section *ms)
>>   {
>> -    /*
>> -     * XXX: Freeing memmap with vmemmap is not implement yet.
>> -     *      This should be removed later.
>> -     */
>> -    return -EBUSY;
>> +    int ret = -EINVAL;
>> +
>> +    if (!valid_section(ms))
>> +        return ret;
>> +
>> +    ret = unregister_memory_section(ms);
>> +
>> +    return ret;
>>   }
>>   #else
>>   static int __remove_section(struct zone *zone, struct mem_section *ms)
> 
> 

Re: [PATCH v3 06/12] memory-hotplug: unregister memory section on SPARSEMEM_VMEMMAP

[Jaegeuk Hanse]

On 11/21/2012 11:05 AM, Wen Congyang wrote:
> At 11/20/2012 07:16 PM, Jaegeuk Hanse Wrote:
>> On 11/01/2012 05:44 PM, Wen Congyang wrote:
>>> From: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
>>>
>>> Currently __remove_section for SPARSEMEM_VMEMMAP does nothing. But
>>> even if
>>> we use SPARSEMEM_VMEMMAP, we can unregister the memory_section.
>>>
>>> So the patch add unregister_memory_section() into __remove_section().
>> Hi Yasuaki,
>>
>> I have a question about these sparse vmemmap memory related patches. Hot
>> add memory need allocated vmemmap pages, but this time is allocated by
>> buddy system. How can gurantee virtual address is continuous to the
>> address allocated before? If not continuous, page_to_pfn and pfn_to_page
>> can't work correctly.
> vmemmap has its virtual address range:
> ffffea0000000000 - ffffeaffffffffff (=40 bits) virtual memory map (1TB)
>
> We allocate memory from buddy system to store struct page, and its virtual
> address isn't in this range. So we should update the page table:
>
> kmalloc_section_memmap()
>      sparse_mem_map_populate()
>          pfn_to_page() // get the virtual address in the vmemmap range
>          vmemmap_populate() // we update page table here
>
> When we use vmemmap, page_to_pfn() always returns address in the vmemmap
> range, not the address that kmalloc() returns. So the virtual address
> is continuous.

Hi Congyang,

Another question about memory hotplug. During hot remove memory, it will 
also call memblock_remove to remove related memblock.
memblock_remove()
            __memblock_remove()
                    memblock_isolate_range()
                    memblock_remove_region()

But memblock_isolate_range() only record fully contained regions, 
regions which are partial overlapped just be splitted instead of record. 
So these partial overlapped regions can't be removed. Where I miss?

Regards,
Jaegeuk

> Thanks
> Wen Congyang
>> Regards,
>> Jaegeuk
>>
>>> CC: David Rientjes <rientjes@google.com>
>>> CC: Jiang Liu <liuj97@gmail.com>
>>> CC: Len Brown <len.brown@intel.com>
>>> 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>
>>> CC: Wen Congyang <wency@cn.fujitsu.com>
>>> Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
>>> ---
>>>    mm/memory_hotplug.c | 13 ++++++++-----
>>>    1 file changed, 8 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
>>> index ca07433..66a79a7 100644
>>> --- a/mm/memory_hotplug.c
>>> +++ b/mm/memory_hotplug.c
>>> @@ -286,11 +286,14 @@ static int __meminit __add_section(int nid,
>>> struct zone *zone,
>>>    #ifdef CONFIG_SPARSEMEM_VMEMMAP
>>>    static int __remove_section(struct zone *zone, struct mem_section *ms)
>>>    {
>>> -    /*
>>> -     * XXX: Freeing memmap with vmemmap is not implement yet.
>>> -     *      This should be removed later.
>>> -     */
>>> -    return -EBUSY;
>>> +    int ret = -EINVAL;
>>> +
>>> +    if (!valid_section(ms))
>>> +        return ret;
>>> +
>>> +    ret = unregister_memory_section(ms);
>>> +
>>> +    return ret;
>>>    }
>>>    #else
>>>    static int __remove_section(struct zone *zone, struct mem_section *ms)
>>

Re: [PATCH v3 06/12] memory-hotplug: unregister memory section on SPARSEMEM_VMEMMAP

[Wen Congyang]

At 11/21/2012 12:22 PM, Jaegeuk Hanse Wrote:
> On 11/21/2012 11:05 AM, Wen Congyang wrote:
>> At 11/20/2012 07:16 PM, Jaegeuk Hanse Wrote:
>>> On 11/01/2012 05:44 PM, Wen Congyang wrote:
>>>> From: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
>>>>
>>>> Currently __remove_section for SPARSEMEM_VMEMMAP does nothing. But
>>>> even if
>>>> we use SPARSEMEM_VMEMMAP, we can unregister the memory_section.
>>>>
>>>> So the patch add unregister_memory_section() into __remove_section().
>>> Hi Yasuaki,
>>>
>>> I have a question about these sparse vmemmap memory related patches. Hot
>>> add memory need allocated vmemmap pages, but this time is allocated by
>>> buddy system. How can gurantee virtual address is continuous to the
>>> address allocated before? If not continuous, page_to_pfn and pfn_to_page
>>> can't work correctly.
>> vmemmap has its virtual address range:
>> ffffea0000000000 - ffffeaffffffffff (=40 bits) virtual memory map (1TB)
>>
>> We allocate memory from buddy system to store struct page, and its
>> virtual
>> address isn't in this range. So we should update the page table:
>>
>> kmalloc_section_memmap()
>>      sparse_mem_map_populate()
>>          pfn_to_page() // get the virtual address in the vmemmap range
>>          vmemmap_populate() // we update page table here
>>
>> When we use vmemmap, page_to_pfn() always returns address in the vmemmap
>> range, not the address that kmalloc() returns. So the virtual address
>> is continuous.
> 
> Hi Congyang,
> 
> Another question about memory hotplug. During hot remove memory, it will
> also call memblock_remove to remove related memblock.

IIRC, we don't touch memblock when hot-add/hot-remove memory. memblock is
only used for bootmem allocator. I think it isn't used after booting.

> memblock_remove()
>            __memblock_remove()
>                    memblock_isolate_range()
>                    memblock_remove_region()
> 
> But memblock_isolate_range() only record fully contained regions,
> regions which are partial overlapped just be splitted instead of record.
> So these partial overlapped regions can't be removed. Where I miss?

No, memblock_isolate_range() can deal with partial overlapped region.
=====================
		if (rbase < base) {
			/*
			 * @rgn intersects from below.  Split and continue
			 * to process the next region - the new top half.
			 */
			rgn->base = base;
			rgn->size -= base - rbase;
			type->total_size -= base - rbase;
			memblock_insert_region(type, i, rbase, base - rbase,
					       memblock_get_region_node(rgn));
		} else if (rend > end) {
			/*
			 * @rgn intersects from above.  Split and redo the
			 * current region - the new bottom half.
			 */
			rgn->base = end;
			rgn->size -= end - rbase;
			type->total_size -= end - rbase;
			memblock_insert_region(type, i--, rbase, end - rbase,
					       memblock_get_region_node(rgn));
=====================

If the region is partial overlapped region, we will split the old region into
two regions. After doing this, it is full contained region now.

Thanks
Wen Congyang

> 
> Regards,
> Jaegeuk
> 
>> Thanks
>> Wen Congyang
>>> Regards,
>>> Jaegeuk
>>>
>>>> CC: David Rientjes <rientjes@google.com>
>>>> CC: Jiang Liu <liuj97@gmail.com>
>>>> CC: Len Brown <len.brown@intel.com>
>>>> 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>
>>>> CC: Wen Congyang <wency@cn.fujitsu.com>
>>>> Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
>>>> ---
>>>>    mm/memory_hotplug.c | 13 ++++++++-----
>>>>    1 file changed, 8 insertions(+), 5 deletions(-)
>>>>
>>>> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
>>>> index ca07433..66a79a7 100644
>>>> --- a/mm/memory_hotplug.c
>>>> +++ b/mm/memory_hotplug.c
>>>> @@ -286,11 +286,14 @@ static int __meminit __add_section(int nid,
>>>> struct zone *zone,
>>>>    #ifdef CONFIG_SPARSEMEM_VMEMMAP
>>>>    static int __remove_section(struct zone *zone, struct mem_section
>>>> *ms)
>>>>    {
>>>> -    /*
>>>> -     * XXX: Freeing memmap with vmemmap is not implement yet.
>>>> -     *      This should be removed later.
>>>> -     */
>>>> -    return -EBUSY;
>>>> +    int ret = -EINVAL;
>>>> +
>>>> +    if (!valid_section(ms))
>>>> +        return ret;
>>>> +
>>>> +    ret = unregister_memory_section(ms);
>>>> +
>>>> +    return ret;
>>>>    }
>>>>    #else
>>>>    static int __remove_section(struct zone *zone, struct mem_section
>>>> *ms)
>>>
> 
> 

Re: [PATCH v3 06/12] memory-hotplug: unregister memory section on SPARSEMEM_VMEMMAP

[Jaegeuk Hanse]

On 11/21/2012 12:42 PM, Wen Congyang wrote:
> At 11/21/2012 12:22 PM, Jaegeuk Hanse Wrote:
>> On 11/21/2012 11:05 AM, Wen Congyang wrote:
>>> At 11/20/2012 07:16 PM, Jaegeuk Hanse Wrote:
>>>> On 11/01/2012 05:44 PM, Wen Congyang wrote:
>>>>> From: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
>>>>>
>>>>> Currently __remove_section for SPARSEMEM_VMEMMAP does nothing. But
>>>>> even if
>>>>> we use SPARSEMEM_VMEMMAP, we can unregister the memory_section.
>>>>>
>>>>> So the patch add unregister_memory_section() into __remove_section().
>>>> Hi Yasuaki,
>>>>
>>>> I have a question about these sparse vmemmap memory related patches. Hot
>>>> add memory need allocated vmemmap pages, but this time is allocated by
>>>> buddy system. How can gurantee virtual address is continuous to the
>>>> address allocated before? If not continuous, page_to_pfn and pfn_to_page
>>>> can't work correctly.
>>> vmemmap has its virtual address range:
>>> ffffea0000000000 - ffffeaffffffffff (=40 bits) virtual memory map (1TB)
>>>
>>> We allocate memory from buddy system to store struct page, and its
>>> virtual
>>> address isn't in this range. So we should update the page table:
>>>
>>> kmalloc_section_memmap()
>>>       sparse_mem_map_populate()
>>>           pfn_to_page() // get the virtual address in the vmemmap range
>>>           vmemmap_populate() // we update page table here
>>>
>>> When we use vmemmap, page_to_pfn() always returns address in the vmemmap
>>> range, not the address that kmalloc() returns. So the virtual address
>>> is continuous.
>> Hi Congyang,
>>
>> Another question about memory hotplug. During hot remove memory, it will
>> also call memblock_remove to remove related memblock.
> IIRC, we don't touch memblock when hot-add/hot-remove memory. memblock is
> only used for bootmem allocator. I think it isn't used after booting.

In IBM pseries servers.

pseries_remove_memory()
     pseries_remove_memblock()
         memblock_remove()

Furthermore, memblock is set to record available memory ranges get from 
e820 map(you can check it in memblock_x86_fill()) in x86 case, after 
hot-remove memory, this range of memory can't be available, why not 
remove them as pseries servers' codes do.

>> memblock_remove()
>>             __memblock_remove()memory-hotplug: unregister memory section on SPARSEMEM_VMEMMAP
>>
>>                     memblock_isolate_range()
>>                     memblock_remove_region()
>>
>> But memblock_isolate_range() only record fully contained regions,
>> regions which are partial overlapped just be splitted instead of record.
>> So these partial overlapped regions can't be removed. Where I miss?
> No, memblock_isolate_range() can deal with partial overlapped region.
> =====================
> 		if (rbase < base) {
> 			/*
> 			 * @rgn intersects from below.  Split and continue
> 			 * to process the next region - the new top half.
> 			 */
> 			rgn->base = base;
> 			rgn->size -= base - rbase;
> 			type->total_size -= base - rbase;
> 			memblock_insert_region(type, i, rbase, base - rbase,
> 					       memblock_get_region_node(rgn));
> 		} else if (rend > end) {
> 			/*
> 			 * @rgn intersects from above.  Split and redo the
> 			 * current region - the new bottom half.
> 			 */
> 			rgn->base = end;
> 			rgn->size -= end - rbase;
> 			type->total_size -= end - rbase;
> 			memblock_insert_region(type, i--, rbase, end - rbase,
> 					       memblock_get_region_node(rgn));
> =====================
>
> If the region is partial overlapped region, we will split the old region into
> two regions. After doing this, it is full contained region now.

You are right, I misunderstand the codes.

>
> Thanks
> Wen Congyang
>
>> Regards,
>> Jaegeuk
>>
>>> Thanks
>>> Wen Congyang
>>>> Regards,
>>>> Jaegeuk
>>>>
>>>>> CC: David Rientjes <rientjes@google.com>
>>>>> CC: Jiang Liu <liuj97@gmail.com>
>>>>> CC: Len Brown <len.brown@intel.com>
>>>>> 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>
>>>>> CC: Wen Congyang <wency@cn.fujitsu.com>
>>>>> Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
>>>>> ---
>>>>>     mm/memory_hotplug.c | 13 ++++++++-----
>>>>>     1 file changed, 8 insertions(+), 5 deletions(-)
>>>>>
>>>>> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
>>>>> index ca07433..66a79a7 100644
>>>>> --- a/mm/memory_hotplug.c
>>>>> +++ b/mm/memory_hotplug.c
>>>>> @@ -286,11 +286,14 @@ static int __meminit __add_section(int nid,
>>>>> struct zone *zone,
>>>>>     #ifdef CONFIG_SPARSEMEM_VMEMMAP
>>>>>     static int __remove_section(struct zone *zone, struct mem_section
>>>>> *ms)
>>>>>     {
>>>>> -    /*
>>>>> -     * XXX: Freeing memmap with vmemmap is not implement yet.
>>>>> -     *      This should be removed later.
>>>>> -     */
>>>>> -    return -EBUSY;
>>>>> +    int ret = -EINVAL;
>>>>> +
>>>>> +    if (!valid_section(ms))
>>>>> +        return ret;
>>>>> +
>>>>> +    ret = unregister_memory_section(ms);
>>>>> +
>>>>> +    return ret;
>>>>>     }
>>>>>     #else
>>>>>     static int __remove_section(struct zone *zone, struct mem_section
>>>>> *ms)
>>

Re: [PATCH v3 06/12] memory-hotplug: unregister memory section on SPARSEMEM_VMEMMAP

[Wen Congyang]

At 11/21/2012 01:03 PM, Jaegeuk Hanse Wrote:
> On 11/21/2012 12:42 PM, Wen Congyang wrote:
>> At 11/21/2012 12:22 PM, Jaegeuk Hanse Wrote:
>>> On 11/21/2012 11:05 AM, Wen Congyang wrote:
>>>> At 11/20/2012 07:16 PM, Jaegeuk Hanse Wrote:
>>>>> On 11/01/2012 05:44 PM, Wen Congyang wrote:
>>>>>> From: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
>>>>>>
>>>>>> Currently __remove_section for SPARSEMEM_VMEMMAP does nothing. But
>>>>>> even if
>>>>>> we use SPARSEMEM_VMEMMAP, we can unregister the memory_section.
>>>>>>
>>>>>> So the patch add unregister_memory_section() into __remove_section().
>>>>> Hi Yasuaki,
>>>>>
>>>>> I have a question about these sparse vmemmap memory related
>>>>> patches. Hot
>>>>> add memory need allocated vmemmap pages, but this time is allocated by
>>>>> buddy system. How can gurantee virtual address is continuous to the
>>>>> address allocated before? If not continuous, page_to_pfn and
>>>>> pfn_to_page
>>>>> can't work correctly.
>>>> vmemmap has its virtual address range:
>>>> ffffea0000000000 - ffffeaffffffffff (=40 bits) virtual memory map (1TB)
>>>>
>>>> We allocate memory from buddy system to store struct page, and its
>>>> virtual
>>>> address isn't in this range. So we should update the page table:
>>>>
>>>> kmalloc_section_memmap()
>>>>       sparse_mem_map_populate()
>>>>           pfn_to_page() // get the virtual address in the vmemmap range
>>>>           vmemmap_populate() // we update page table here
>>>>
>>>> When we use vmemmap, page_to_pfn() always returns address in the
>>>> vmemmap
>>>> range, not the address that kmalloc() returns. So the virtual address
>>>> is continuous.
>>> Hi Congyang,
>>>
>>> Another question about memory hotplug. During hot remove memory, it will
>>> also call memblock_remove to remove related memblock.
>> IIRC, we don't touch memblock when hot-add/hot-remove memory. memblock is
>> only used for bootmem allocator. I think it isn't used after booting.
> 
> In IBM pseries servers.
> 
> pseries_remove_memory()
>     pseries_remove_memblock()
>         memblock_remove()
> 
> Furthermore, memblock is set to record available memory ranges get from
> e820 map(you can check it in memblock_x86_fill()) in x86 case, after
> hot-remove memory, this range of memory can't be available, why not
> remove them as pseries servers' codes do.

Oh, it is powerpc, and I don't read this code. I will check it now.

Thanks for pointing it out.

Wen Congyang

> 
>>> memblock_remove()
>>>             __memblock_remove()memory-hotplug: unregister memory
>>> section on SPARSEMEM_VMEMMAP
>>>
>>>                     memblock_isolate_range()
>>>                     memblock_remove_region()
>>>
>>> But memblock_isolate_range() only record fully contained regions,
>>> regions which are partial overlapped just be splitted instead of record.
>>> So these partial overlapped regions can't be removed. Where I miss?
>> No, memblock_isolate_range() can deal with partial overlapped region.
>> =====================
>>         if (rbase < base) {
>>             /*
>>              * @rgn intersects from below.  Split and continue
>>              * to process the next region - the new top half.
>>              */
>>             rgn->base = base;
>>             rgn->size -= base - rbase;
>>             type->total_size -= base - rbase;
>>             memblock_insert_region(type, i, rbase, base - rbase,
>>                            memblock_get_region_node(rgn));
>>         } else if (rend > end) {
>>             /*
>>              * @rgn intersects from above.  Split and redo the
>>              * current region - the new bottom half.
>>              */
>>             rgn->base = end;
>>             rgn->size -= end - rbase;
>>             type->total_size -= end - rbase;
>>             memblock_insert_region(type, i--, rbase, end - rbase,
>>                            memblock_get_region_node(rgn));
>> =====================
>>
>> If the region is partial overlapped region, we will split the old
>> region into
>> two regions. After doing this, it is full contained region now.
> 
> You are right, I misunderstand the codes.
> 
>>
>> Thanks
>> Wen Congyang
>>
>>> Regards,
>>> Jaegeuk
>>>
>>>> Thanks
>>>> Wen Congyang
>>>>> Regards,
>>>>> Jaegeuk
>>>>>
>>>>>> CC: David Rientjes <rientjes@google.com>
>>>>>> CC: Jiang Liu <liuj97@gmail.com>
>>>>>> CC: Len Brown <len.brown@intel.com>
>>>>>> 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>
>>>>>> CC: Wen Congyang <wency@cn.fujitsu.com>
>>>>>> Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
>>>>>> ---
>>>>>>     mm/memory_hotplug.c | 13 ++++++++-----
>>>>>>     1 file changed, 8 insertions(+), 5 deletions(-)
>>>>>>
>>>>>> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
>>>>>> index ca07433..66a79a7 100644
>>>>>> --- a/mm/memory_hotplug.c
>>>>>> +++ b/mm/memory_hotplug.c
>>>>>> @@ -286,11 +286,14 @@ static int __meminit __add_section(int nid,
>>>>>> struct zone *zone,
>>>>>>     #ifdef CONFIG_SPARSEMEM_VMEMMAP
>>>>>>     static int __remove_section(struct zone *zone, struct mem_section
>>>>>> *ms)
>>>>>>     {
>>>>>> -    /*
>>>>>> -     * XXX: Freeing memmap with vmemmap is not implement yet.
>>>>>> -     *      This should be removed later.
>>>>>> -     */
>>>>>> -    return -EBUSY;
>>>>>> +    int ret = -EINVAL;
>>>>>> +
>>>>>> +    if (!valid_section(ms))
>>>>>> +        return ret;
>>>>>> +
>>>>>> +    ret = unregister_memory_section(ms);
>>>>>> +
>>>>>> +    return ret;
>>>>>>     }
>>>>>>     #else
>>>>>>     static int __remove_section(struct zone *zone, struct mem_section
>>>>>> *ms)
>>>
> 
> 

Re: [PATCH v3 06/12] memory-hotplug: unregister memory section on SPARSEMEM_VMEMMAP

[Wen Congyang]

At 11/21/2012 01:03 PM, Jaegeuk Hanse Wrote:
> On 11/21/2012 12:42 PM, Wen Congyang wrote:
>> At 11/21/2012 12:22 PM, Jaegeuk Hanse Wrote:
>>> On 11/21/2012 11:05 AM, Wen Congyang wrote:
>>>> At 11/20/2012 07:16 PM, Jaegeuk Hanse Wrote:
>>>>> On 11/01/2012 05:44 PM, Wen Congyang wrote:
>>>>>> From: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
>>>>>>
>>>>>> Currently __remove_section for SPARSEMEM_VMEMMAP does nothing. But
>>>>>> even if
>>>>>> we use SPARSEMEM_VMEMMAP, we can unregister the memory_section.
>>>>>>
>>>>>> So the patch add unregister_memory_section() into __remove_section().
>>>>> Hi Yasuaki,
>>>>>
>>>>> I have a question about these sparse vmemmap memory related
>>>>> patches. Hot
>>>>> add memory need allocated vmemmap pages, but this time is allocated by
>>>>> buddy system. How can gurantee virtual address is continuous to the
>>>>> address allocated before? If not continuous, page_to_pfn and
>>>>> pfn_to_page
>>>>> can't work correctly.
>>>> vmemmap has its virtual address range:
>>>> ffffea0000000000 - ffffeaffffffffff (=40 bits) virtual memory map (1TB)
>>>>
>>>> We allocate memory from buddy system to store struct page, and its
>>>> virtual
>>>> address isn't in this range. So we should update the page table:
>>>>
>>>> kmalloc_section_memmap()
>>>>       sparse_mem_map_populate()
>>>>           pfn_to_page() // get the virtual address in the vmemmap range
>>>>           vmemmap_populate() // we update page table here
>>>>
>>>> When we use vmemmap, page_to_pfn() always returns address in the
>>>> vmemmap
>>>> range, not the address that kmalloc() returns. So the virtual address
>>>> is continuous.
>>> Hi Congyang,
>>>
>>> Another question about memory hotplug. During hot remove memory, it will
>>> also call memblock_remove to remove related memblock.
>> IIRC, we don't touch memblock when hot-add/hot-remove memory. memblock is
>> only used for bootmem allocator. I think it isn't used after booting.
> 
> In IBM pseries servers.
> 
> pseries_remove_memory()
>     pseries_remove_memblock()
>         memblock_remove()

It seems that pseries servers don't use ACPI(ACPI is only supported for
ia64 and x86 now. arm will be supported in the furture).

I am not ppc expert, and I don't know why we touch memblock when hotadding
memory in ppc case. But IIRC, we don't need memblock after the machine has
booted up in x86 case. So there is no need to touch it when hotadd/hotremove
the memory in x86 case.

Thanks
Wen Congyang

> 
> Furthermore, memblock is set to record available memory ranges get from
> e820 map(you can check it in memblock_x86_fill()) in x86 case, after
> hot-remove memory, this range of memory can't be available, why not
> remove them as pseries servers' codes do.
> 
>>> memblock_remove()
>>>             __memblock_remove()memory-hotplug: unregister memory
>>> section on SPARSEMEM_VMEMMAP
>>>
>>>                     memblock_isolate_range()
>>>                     memblock_remove_region()
>>>
>>> But memblock_isolate_range() only record fully contained regions,
>>> regions which are partial overlapped just be splitted instead of record.
>>> So these partial overlapped regions can't be removed. Where I miss?
>> No, memblock_isolate_range() can deal with partial overlapped region.
>> =====================
>>         if (rbase < base) {
>>             /*
>>              * @rgn intersects from below.  Split and continue
>>              * to process the next region - the new top half.
>>              */
>>             rgn->base = base;
>>             rgn->size -= base - rbase;
>>             type->total_size -= base - rbase;
>>             memblock_insert_region(type, i, rbase, base - rbase,
>>                            memblock_get_region_node(rgn));
>>         } else if (rend > end) {
>>             /*
>>              * @rgn intersects from above.  Split and redo the
>>              * current region - the new bottom half.
>>              */
>>             rgn->base = end;
>>             rgn->size -= end - rbase;
>>             type->total_size -= end - rbase;
>>             memblock_insert_region(type, i--, rbase, end - rbase,
>>                            memblock_get_region_node(rgn));
>> =====================
>>
>> If the region is partial overlapped region, we will split the old
>> region into
>> two regions. After doing this, it is full contained region now.
> 
> You are right, I misunderstand the codes.
> 
>>
>> Thanks
>> Wen Congyang
>>
>>> Regards,
>>> Jaegeuk
>>>
>>>> Thanks
>>>> Wen Congyang
>>>>> Regards,
>>>>> Jaegeuk
>>>>>
>>>>>> CC: David Rientjes <rientjes@google.com>
>>>>>> CC: Jiang Liu <liuj97@gmail.com>
>>>>>> CC: Len Brown <len.brown@intel.com>
>>>>>> 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>
>>>>>> CC: Wen Congyang <wency@cn.fujitsu.com>
>>>>>> Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
>>>>>> ---
>>>>>>     mm/memory_hotplug.c | 13 ++++++++-----
>>>>>>     1 file changed, 8 insertions(+), 5 deletions(-)
>>>>>>
>>>>>> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
>>>>>> index ca07433..66a79a7 100644
>>>>>> --- a/mm/memory_hotplug.c
>>>>>> +++ b/mm/memory_hotplug.c
>>>>>> @@ -286,11 +286,14 @@ static int __meminit __add_section(int nid,
>>>>>> struct zone *zone,
>>>>>>     #ifdef CONFIG_SPARSEMEM_VMEMMAP
>>>>>>     static int __remove_section(struct zone *zone, struct mem_section
>>>>>> *ms)
>>>>>>     {
>>>>>> -    /*
>>>>>> -     * XXX: Freeing memmap with vmemmap is not implement yet.
>>>>>> -     *      This should be removed later.
>>>>>> -     */
>>>>>> -    return -EBUSY;
>>>>>> +    int ret = -EINVAL;
>>>>>> +
>>>>>> +    if (!valid_section(ms))
>>>>>> +        return ret;
>>>>>> +
>>>>>> +    ret = unregister_memory_section(ms);
>>>>>> +
>>>>>> +    return ret;
>>>>>>     }
>>>>>>     #else
>>>>>>     static int __remove_section(struct zone *zone, struct mem_section
>>>>>> *ms)
>>>
> 
> 

[PATCH v3 07/12] memory-hotplug: implement register_page_bootmem_info_section of sparse-vmemmap

[Wen Congyang]

From: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>

For removing memmap region of sparse-vmemmap which is allocated bootmem,
memmap region of sparse-vmemmap needs to be registered by get_page_bootmem().
So the patch searches pages of virtual mapping and registers the pages by
get_page_bootmem().

Note: register_page_bootmem_memmap() is not implemented for ia64, ppc, s390,
and sparc.

CC: David Rientjes <rientjes@google.com>
CC: Jiang Liu <liuj97@gmail.com>
CC: Len Brown <len.brown@intel.com>
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: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
---
 arch/ia64/mm/discontig.c       |  6 +++++
 arch/powerpc/mm/init_64.c      |  6 +++++
 arch/s390/mm/vmem.c            |  6 +++++
 arch/sparc/mm/init_64.c        |  6 +++++
 arch/x86/mm/init_64.c          | 52 ++++++++++++++++++++++++++++++++++++++++++
 include/linux/memory_hotplug.h | 11 ++-------
 include/linux/mm.h             |  3 ++-
 mm/memory_hotplug.c            | 37 ++++++++++++++++++++++++++----
 8 files changed, 113 insertions(+), 14 deletions(-)

diff --git a/arch/ia64/mm/discontig.c b/arch/ia64/mm/discontig.c
index c641333..33943db 100644
--- a/arch/ia64/mm/discontig.c
+++ b/arch/ia64/mm/discontig.c
@@ -822,4 +822,10 @@ int __meminit vmemmap_populate(struct page *start_page,
 {
 	return vmemmap_populate_basepages(start_page, size, node);
 }
+
+void register_page_bootmem_memmap(unsigned long section_nr,
+				  struct page *start_page, unsigned long size)
+{
+	/* TODO */
+}
 #endif
diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
index 95a4529..6466440 100644
--- a/arch/powerpc/mm/init_64.c
+++ b/arch/powerpc/mm/init_64.c
@@ -297,5 +297,11 @@ int __meminit vmemmap_populate(struct page *start_page,
 
 	return 0;
 }
+
+void register_page_bootmem_memmap(unsigned long section_nr,
+				  struct page *start_page, unsigned long size)
+{
+	/* TODO */
+}
 #endif /* CONFIG_SPARSEMEM_VMEMMAP */
 
diff --git a/arch/s390/mm/vmem.c b/arch/s390/mm/vmem.c
index 387c7c6..4f4803a 100644
--- a/arch/s390/mm/vmem.c
+++ b/arch/s390/mm/vmem.c
@@ -236,6 +236,12 @@ out:
 	return ret;
 }
 
+void register_page_bootmem_memmap(unsigned long section_nr,
+				  struct page *start_page, unsigned long size)
+{
+	/* TODO */
+}
+
 /*
  * Add memory segment to the segment list if it doesn't overlap with
  * an already present segment.
diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c
index 9e28a11..75a984b 100644
--- a/arch/sparc/mm/init_64.c
+++ b/arch/sparc/mm/init_64.c
@@ -2231,6 +2231,12 @@ void __meminit vmemmap_populate_print_last(void)
 		node_start = 0;
 	}
 }
+
+void register_page_bootmem_memmap(unsigned long section_nr,
+				  struct page *start_page, unsigned long size)
+{
+	/* TODO */
+}
 #endif /* CONFIG_SPARSEMEM_VMEMMAP */
 
 static void prot_init_common(unsigned long page_none,
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 5675335..795dae3 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -998,6 +998,58 @@ vmemmap_populate(struct page *start_page, unsigned long size, int node)
 	return 0;
 }
 
+void register_page_bootmem_memmap(unsigned long section_nr,
+				  struct page *start_page, unsigned long size)
+{
+	unsigned long addr = (unsigned long)start_page;
+	unsigned long end = (unsigned long)(start_page + size);
+	unsigned long next;
+	pgd_t *pgd;
+	pud_t *pud;
+	pmd_t *pmd;
+
+	for (; addr < end; addr = next) {
+		pte_t *pte = NULL;
+
+		pgd = pgd_offset_k(addr);
+		if (pgd_none(*pgd)) {
+			next = (addr + PAGE_SIZE) & PAGE_MASK;
+			continue;
+		}
+		get_page_bootmem(section_nr, pgd_page(*pgd), MIX_SECTION_INFO);
+
+		pud = pud_offset(pgd, addr);
+		if (pud_none(*pud)) {
+			next = (addr + PAGE_SIZE) & PAGE_MASK;
+			continue;
+		}
+		get_page_bootmem(section_nr, pud_page(*pud), MIX_SECTION_INFO);
+
+		if (!cpu_has_pse) {
+			next = (addr + PAGE_SIZE) & PAGE_MASK;
+			pmd = pmd_offset(pud, addr);
+			if (pmd_none(*pmd))
+				continue;
+			get_page_bootmem(section_nr, pmd_page(*pmd),
+					 MIX_SECTION_INFO);
+
+			pte = pte_offset_kernel(pmd, addr);
+			if (pte_none(*pte))
+				continue;
+			get_page_bootmem(section_nr, pte_page(*pte),
+					 SECTION_INFO);
+		} else {
+			next = pmd_addr_end(addr, end);
+
+			pmd = pmd_offset(pud, addr);
+			if (pmd_none(*pmd))
+				continue;
+			get_page_bootmem(section_nr, pmd_page(*pmd),
+					 SECTION_INFO);
+		}
+	}
+}
+
 void __meminit vmemmap_populate_print_last(void)
 {
 	if (p_start) {
diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index 191b2d9..d4c4402 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -163,17 +163,10 @@ static inline void arch_refresh_nodedata(int nid, pg_data_t *pgdat)
 #endif /* CONFIG_NUMA */
 #endif /* CONFIG_HAVE_ARCH_NODEDATA_EXTENSION */
 
-#ifdef CONFIG_SPARSEMEM_VMEMMAP
-static inline void register_page_bootmem_info_node(struct pglist_data *pgdat)
-{
-}
-static inline void put_page_bootmem(struct page *page)
-{
-}
-#else
 extern void register_page_bootmem_info_node(struct pglist_data *pgdat);
 extern void put_page_bootmem(struct page *page);
-#endif
+extern void get_page_bootmem(unsigned long ingo, struct page *page,
+			     unsigned long type);
 
 /*
  * Lock for memory hotplug guarantees 1) all callbacks for memory hotplug
diff --git a/include/linux/mm.h b/include/linux/mm.h
index fa06804..8e5a56f 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1640,7 +1640,8 @@ int vmemmap_populate_basepages(struct page *start_page,
 						unsigned long pages, int node);
 int vmemmap_populate(struct page *start_page, unsigned long pages, int node);
 void vmemmap_populate_print_last(void);
-
+void register_page_bootmem_memmap(unsigned long section_nr, struct page *map,
+				  unsigned long size);
 
 enum mf_flags {
 	MF_COUNT_INCREASED = 1 << 0,
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 66a79a7..db9806c 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -91,9 +91,8 @@ static void release_memory_resource(struct resource *res)
 }
 
 #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
-#ifndef CONFIG_SPARSEMEM_VMEMMAP
-static void get_page_bootmem(unsigned long info,  struct page *page,
-			     unsigned long type)
+void get_page_bootmem(unsigned long info,  struct page *page,
+		      unsigned long type)
 {
 	page->lru.next = (struct list_head *) type;
 	SetPagePrivate(page);
@@ -127,6 +126,7 @@ void __ref put_page_bootmem(struct page *page)
 
 }
 
+#ifndef CONFIG_SPARSEMEM_VMEMMAP
 static void register_page_bootmem_info_section(unsigned long start_pfn)
 {
 	unsigned long *usemap, mapsize, section_nr, i;
@@ -160,6 +160,36 @@ static void register_page_bootmem_info_section(unsigned long start_pfn)
 		get_page_bootmem(section_nr, page, MIX_SECTION_INFO);
 
 }
+#else
+static void register_page_bootmem_info_section(unsigned long start_pfn)
+{
+	unsigned long *usemap, mapsize, section_nr, i;
+	struct mem_section *ms;
+	struct page *page, *memmap;
+
+	if (!pfn_valid(start_pfn))
+		return;
+
+	section_nr = pfn_to_section_nr(start_pfn);
+	ms = __nr_to_section(section_nr);
+
+	memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
+
+	page = virt_to_page(memmap);
+	mapsize = sizeof(struct page) * PAGES_PER_SECTION;
+	mapsize = PAGE_ALIGN(mapsize) >> PAGE_SHIFT;
+
+	register_page_bootmem_memmap(section_nr, memmap, PAGES_PER_SECTION);
+
+	usemap = __nr_to_section(section_nr)->pageblock_flags;
+	page = virt_to_page(usemap);
+
+	mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT;
+
+	for (i = 0; i < mapsize; i++, page++)
+		get_page_bootmem(section_nr, page, MIX_SECTION_INFO);
+}
+#endif
 
 void register_page_bootmem_info_node(struct pglist_data *pgdat)
 {
@@ -202,7 +232,6 @@ void register_page_bootmem_info_node(struct pglist_data *pgdat)
 			register_page_bootmem_info_section(pfn);
 	}
 }
-#endif /* !CONFIG_SPARSEMEM_VMEMMAP */
 
 static void grow_zone_span(struct zone *zone, unsigned long start_pfn,
 			   unsigned long end_pfn)
-- 
1.8.0

[PATCH v3 08/12] memory-hotplug: remove memmap of sparse-vmemmap

[Wen Congyang]

From: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>

All pages of virtual mapping in removed memory cannot be freed, since some pages
used as PGD/PUD includes not only removed memory but also other memory. So the
patch checks whether page can be freed or not.

How to check whether page can be freed or not?
 1. When removing memory, the page structs of the revmoved memory are filled
    with 0FD.
 2. All page structs are filled with 0xFD on PT/PMD, PT/PMD can be cleared.
    In this case, the page used as PT/PMD can be freed.

Applying patch, __remove_section() of CONFIG_SPARSEMEM_VMEMMAP is integrated
into one. So __remove_section() of CONFIG_SPARSEMEM_VMEMMAP is deleted.

Note:  vmemmap_kfree() and vmemmap_free_bootmem() are not implemented for ia64,
ppc, s390, and sparc.

CC: David Rientjes <rientjes@google.com>
CC: Jiang Liu <liuj97@gmail.com>
CC: Len Brown <len.brown@intel.com>
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>
CC: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
---
 arch/ia64/mm/discontig.c  |   8 ++++
 arch/powerpc/mm/init_64.c |   8 ++++
 arch/s390/mm/vmem.c       |   8 ++++
 arch/sparc/mm/init_64.c   |   8 ++++
 arch/x86/mm/init_64.c     | 119 ++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/mm.h        |   2 +
 mm/memory_hotplug.c       |  17 +------
 mm/sparse.c               |   5 +-
 8 files changed, 158 insertions(+), 17 deletions(-)

diff --git a/arch/ia64/mm/discontig.c b/arch/ia64/mm/discontig.c
index 33943db..0d23b69 100644
--- a/arch/ia64/mm/discontig.c
+++ b/arch/ia64/mm/discontig.c
@@ -823,6 +823,14 @@ int __meminit vmemmap_populate(struct page *start_page,
 	return vmemmap_populate_basepages(start_page, size, node);
 }
 
+void vmemmap_kfree(struct page *memmap, unsigned long nr_pages)
+{
+}
+
+void vmemmap_free_bootmem(struct page *memmap, unsigned long nr_pages)
+{
+}
+
 void register_page_bootmem_memmap(unsigned long section_nr,
 				  struct page *start_page, unsigned long size)
 {
diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
index 6466440..df7d155 100644
--- a/arch/powerpc/mm/init_64.c
+++ b/arch/powerpc/mm/init_64.c
@@ -298,6 +298,14 @@ int __meminit vmemmap_populate(struct page *start_page,
 	return 0;
 }
 
+void vmemmap_kfree(struct page *memmap, unsigned long nr_pages)
+{
+}
+
+void vmemmap_free_bootmem(struct page *memmap, unsigned long nr_pages)
+{
+}
+
 void register_page_bootmem_memmap(unsigned long section_nr,
 				  struct page *start_page, unsigned long size)
 {
diff --git a/arch/s390/mm/vmem.c b/arch/s390/mm/vmem.c
index 4f4803a..ab69c34 100644
--- a/arch/s390/mm/vmem.c
+++ b/arch/s390/mm/vmem.c
@@ -236,6 +236,14 @@ out:
 	return ret;
 }
 
+void vmemmap_kfree(struct page *memmap, unsigned long nr_pages)
+{
+}
+
+void vmemmap_free_bootmem(struct page *memmap, unsigned long nr_pages)
+{
+}
+
 void register_page_bootmem_memmap(unsigned long section_nr,
 				  struct page *start_page, unsigned long size)
 {
diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c
index 75a984b..546855d 100644
--- a/arch/sparc/mm/init_64.c
+++ b/arch/sparc/mm/init_64.c
@@ -2232,6 +2232,14 @@ void __meminit vmemmap_populate_print_last(void)
 	}
 }
 
+void vmemmap_kfree(struct page *memmap, unsigned long nr_pages)
+{
+}
+
+void vmemmap_free_bootmem(struct page *memmap, unsigned long nr_pages)
+{
+}
+
 void register_page_bootmem_memmap(unsigned long section_nr,
 				  struct page *start_page, unsigned long size)
 {
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 795dae3..e85626d 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -998,6 +998,125 @@ vmemmap_populate(struct page *start_page, unsigned long size, int node)
 	return 0;
 }
 
+#define PAGE_INUSE 0xFD
+
+unsigned long find_and_clear_pte_page(unsigned long addr, unsigned long end,
+			    struct page **pp, int *page_size)
+{
+	pgd_t *pgd;
+	pud_t *pud;
+	pmd_t *pmd;
+	pte_t *pte = NULL;
+	void *page_addr;
+	unsigned long next;
+
+	*pp = NULL;
+
+	pgd = pgd_offset_k(addr);
+	if (pgd_none(*pgd))
+		return pgd_addr_end(addr, end);
+
+	pud = pud_offset(pgd, addr);
+	if (pud_none(*pud))
+		return pud_addr_end(addr, end);
+
+	if (!cpu_has_pse) {
+		next = (addr + PAGE_SIZE) & PAGE_MASK;
+		pmd = pmd_offset(pud, addr);
+		if (pmd_none(*pmd))
+			return next;
+
+		pte = pte_offset_kernel(pmd, addr);
+		if (pte_none(*pte))
+			return next;
+
+		*page_size = PAGE_SIZE;
+		*pp = pte_page(*pte);
+	} else {
+		next = pmd_addr_end(addr, end);
+
+		pmd = pmd_offset(pud, addr);
+		if (pmd_none(*pmd))
+			return next;
+
+		*page_size = PMD_SIZE;
+		*pp = pmd_page(*pmd);
+	}
+
+	/*
+	 * Removed page structs are filled with 0xFD.
+	 */
+	memset((void *)addr, PAGE_INUSE, next - addr);
+
+	page_addr = page_address(*pp);
+
+	/*
+	 * Check the page is filled with 0xFD or not.
+	 * memchr_inv() returns the address. In this case, we cannot
+	 * clear PTE/PUD entry, since the page is used by other.
+	 * So we cannot also free the page.
+	 *
+	 * memchr_inv() returns NULL. In this case, we can clear
+	 * PTE/PUD entry, since the page is not used by other.
+	 * So we can also free the page.
+	 */
+	if (memchr_inv(page_addr, PAGE_INUSE, *page_size)) {
+		*pp = NULL;
+		return next;
+	}
+
+	if (!cpu_has_pse)
+		pte_clear(&init_mm, addr, pte);
+	else
+		pmd_clear(pmd);
+
+	return next;
+}
+
+void vmemmap_kfree(struct page *memmap, unsigned long nr_pages)
+{
+	unsigned long addr = (unsigned long)memmap;
+	unsigned long end = (unsigned long)(memmap + nr_pages);
+	unsigned long next;
+	struct page *page;
+	int page_size;
+
+	for (; addr < end; addr = next) {
+		page = NULL;
+		page_size = 0;
+		next = find_and_clear_pte_page(addr, end, &page, &page_size);
+		if (!page)
+			continue;
+
+		free_pages((unsigned long)page_address(page),
+			    get_order(page_size));
+		__flush_tlb_one(addr);
+	}
+}
+
+void vmemmap_free_bootmem(struct page *memmap, unsigned long nr_pages)
+{
+	unsigned long addr = (unsigned long)memmap;
+	unsigned long end = (unsigned long)(memmap + nr_pages);
+	unsigned long next;
+	struct page *page;
+	int page_size;
+	unsigned long magic;
+
+	for (; addr < end; addr = next) {
+		page = NULL;
+		page_size = 0;
+		next = find_and_clear_pte_page(addr, end, &page, &page_size);
+		if (!page)
+			continue;
+
+		magic = (unsigned long) page->lru.next;
+		if (magic == SECTION_INFO)
+			put_page_bootmem(page);
+		flush_tlb_kernel_range(addr, end);
+	}
+}
+
 void register_page_bootmem_memmap(unsigned long section_nr,
 				  struct page *start_page, unsigned long size)
 {
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 8e5a56f..42b8723 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1642,6 +1642,8 @@ int vmemmap_populate(struct page *start_page, unsigned long pages, int node);
 void vmemmap_populate_print_last(void);
 void register_page_bootmem_memmap(unsigned long section_nr, struct page *map,
 				  unsigned long size);
+void vmemmap_kfree(struct page *memmpa, unsigned long nr_pages);
+void vmemmap_free_bootmem(struct page *memmpa, unsigned long nr_pages);
 
 enum mf_flags {
 	MF_COUNT_INCREASED = 1 << 0,
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index db9806c..03153cf 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -312,19 +312,6 @@ static int __meminit __add_section(int nid, struct zone *zone,
 	return register_new_memory(nid, __pfn_to_section(phys_start_pfn));
 }
 
-#ifdef CONFIG_SPARSEMEM_VMEMMAP
-static int __remove_section(struct zone *zone, struct mem_section *ms)
-{
-	int ret = -EINVAL;
-
-	if (!valid_section(ms))
-		return ret;
-
-	ret = unregister_memory_section(ms);
-
-	return ret;
-}
-#else
 static int __remove_section(struct zone *zone, struct mem_section *ms)
 {
 	unsigned long flags;
@@ -341,9 +328,9 @@ static int __remove_section(struct zone *zone, struct mem_section *ms)
 	pgdat_resize_lock(pgdat, &flags);
 	sparse_remove_one_section(zone, ms);
 	pgdat_resize_unlock(pgdat, &flags);
-	return 0;
+
+	return ret;
 }
-#endif
 
 /*
  * Reasonably generic function for adding memory.  It is
diff --git a/mm/sparse.c b/mm/sparse.c
index fac95f2..ab9d755 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -613,12 +613,13 @@ static inline struct page *kmalloc_section_memmap(unsigned long pnum, int nid,
 	/* This will make the necessary allocations eventually. */
 	return sparse_mem_map_populate(pnum, nid);
 }
-static void __kfree_section_memmap(struct page *memmap, unsigned long nr_pages)
+static void __kfree_section_memmap(struct page *page, unsigned long nr_pages)
 {
-	return; /* XXX: Not implemented yet */
+	vmemmap_kfree(page, nr_pages);
 }
 static void free_map_bootmem(struct page *page, unsigned long nr_pages)
 {
+	vmemmap_free_bootmem(page, nr_pages);
 }
 #else
 static struct page *__kmalloc_section_memmap(unsigned long nr_pages)
-- 
1.8.0

Re: [PATCH v3 08/12] memory-hotplug: remove memmap of sparse-vmemmap

[Jianguo Wu]

On 2012/11/1 17:44, Wen Congyang wrote:

> From: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
> 
> All pages of virtual mapping in removed memory cannot be freed, since some pages
> used as PGD/PUD includes not only removed memory but also other memory. So the
> patch checks whether page can be freed or not.
> 
> How to check whether page can be freed or not?
>  1. When removing memory, the page structs of the revmoved memory are filled
>     with 0FD.
>  2. All page structs are filled with 0xFD on PT/PMD, PT/PMD can be cleared.
>     In this case, the page used as PT/PMD can be freed.
> 
> Applying patch, __remove_section() of CONFIG_SPARSEMEM_VMEMMAP is integrated
> into one. So __remove_section() of CONFIG_SPARSEMEM_VMEMMAP is deleted.
> 
> Note:  vmemmap_kfree() and vmemmap_free_bootmem() are not implemented for ia64,
> ppc, s390, and sparc.
> 
> CC: David Rientjes <rientjes@google.com>
> CC: Jiang Liu <liuj97@gmail.com>
> CC: Len Brown <len.brown@intel.com>
> 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>
> CC: Wen Congyang <wency@cn.fujitsu.com>
> Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
> ---
>  arch/ia64/mm/discontig.c  |   8 ++++
>  arch/powerpc/mm/init_64.c |   8 ++++
>  arch/s390/mm/vmem.c       |   8 ++++
>  arch/sparc/mm/init_64.c   |   8 ++++
>  arch/x86/mm/init_64.c     | 119 ++++++++++++++++++++++++++++++++++++++++++++++
>  include/linux/mm.h        |   2 +
>  mm/memory_hotplug.c       |  17 +------
>  mm/sparse.c               |   5 +-
>  8 files changed, 158 insertions(+), 17 deletions(-)
> 
> diff --git a/arch/ia64/mm/discontig.c b/arch/ia64/mm/discontig.c
> index 33943db..0d23b69 100644
> --- a/arch/ia64/mm/discontig.c
> +++ b/arch/ia64/mm/discontig.c
> @@ -823,6 +823,14 @@ int __meminit vmemmap_populate(struct page *start_page,
>  	return vmemmap_populate_basepages(start_page, size, node);
>  }
>  
> +void vmemmap_kfree(struct page *memmap, unsigned long nr_pages)
> +{
> +}
> +
> +void vmemmap_free_bootmem(struct page *memmap, unsigned long nr_pages)
> +{
> +}
> +
>  void register_page_bootmem_memmap(unsigned long section_nr,
>  				  struct page *start_page, unsigned long size)
>  {
> diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
> index 6466440..df7d155 100644
> --- a/arch/powerpc/mm/init_64.c
> +++ b/arch/powerpc/mm/init_64.c
> @@ -298,6 +298,14 @@ int __meminit vmemmap_populate(struct page *start_page,
>  	return 0;
>  }
>  
> +void vmemmap_kfree(struct page *memmap, unsigned long nr_pages)
> +{
> +}
> +
> +void vmemmap_free_bootmem(struct page *memmap, unsigned long nr_pages)
> +{
> +}
> +
>  void register_page_bootmem_memmap(unsigned long section_nr,
>  				  struct page *start_page, unsigned long size)
>  {
> diff --git a/arch/s390/mm/vmem.c b/arch/s390/mm/vmem.c
> index 4f4803a..ab69c34 100644
> --- a/arch/s390/mm/vmem.c
> +++ b/arch/s390/mm/vmem.c
> @@ -236,6 +236,14 @@ out:
>  	return ret;
>  }
>  
> +void vmemmap_kfree(struct page *memmap, unsigned long nr_pages)
> +{
> +}
> +
> +void vmemmap_free_bootmem(struct page *memmap, unsigned long nr_pages)
> +{
> +}
> +
>  void register_page_bootmem_memmap(unsigned long section_nr,
>  				  struct page *start_page, unsigned long size)
>  {
> diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c
> index 75a984b..546855d 100644
> --- a/arch/sparc/mm/init_64.c
> +++ b/arch/sparc/mm/init_64.c
> @@ -2232,6 +2232,14 @@ void __meminit vmemmap_populate_print_last(void)
>  	}
>  }
>  
> +void vmemmap_kfree(struct page *memmap, unsigned long nr_pages)
> +{
> +}
> +
> +void vmemmap_free_bootmem(struct page *memmap, unsigned long nr_pages)
> +{
> +}
> +
>  void register_page_bootmem_memmap(unsigned long section_nr,
>  				  struct page *start_page, unsigned long size)
>  {
> diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
> index 795dae3..e85626d 100644
> --- a/arch/x86/mm/init_64.c
> +++ b/arch/x86/mm/init_64.c
> @@ -998,6 +998,125 @@ vmemmap_populate(struct page *start_page, unsigned long size, int node)
>  	return 0;
>  }
>  
> +#define PAGE_INUSE 0xFD
> +
> +unsigned long find_and_clear_pte_page(unsigned long addr, unsigned long end,
> +			    struct page **pp, int *page_size)
> +{
> +	pgd_t *pgd;
> +	pud_t *pud;
> +	pmd_t *pmd;
> +	pte_t *pte = NULL;
> +	void *page_addr;
> +	unsigned long next;
> +
> +	*pp = NULL;
> +
> +	pgd = pgd_offset_k(addr);
> +	if (pgd_none(*pgd))
> +		return pgd_addr_end(addr, end);
> +
> +	pud = pud_offset(pgd, addr);
> +	if (pud_none(*pud))
> +		return pud_addr_end(addr, end);
> +
> +	if (!cpu_has_pse) {
> +		next = (addr + PAGE_SIZE) & PAGE_MASK;
> +		pmd = pmd_offset(pud, addr);
> +		if (pmd_none(*pmd))
> +			return next;
> +
> +		pte = pte_offset_kernel(pmd, addr);
> +		if (pte_none(*pte))
> +			return next;
> +
> +		*page_size = PAGE_SIZE;
> +		*pp = pte_page(*pte);
> +	} else {
> +		next = pmd_addr_end(addr, end);
> +
> +		pmd = pmd_offset(pud, addr);
> +		if (pmd_none(*pmd))
> +			return next;
> +
> +		*page_size = PMD_SIZE;
> +		*pp = pmd_page(*pmd);
> +	}
> +
> +	/*
> +	 * Removed page structs are filled with 0xFD.
> +	 */
> +	memset((void *)addr, PAGE_INUSE, next - addr);
> +
> +	page_addr = page_address(*pp);
> +
> +	/*
> +	 * Check the page is filled with 0xFD or not.
> +	 * memchr_inv() returns the address. In this case, we cannot
> +	 * clear PTE/PUD entry, since the page is used by other.
> +	 * So we cannot also free the page.
> +	 *
> +	 * memchr_inv() returns NULL. In this case, we can clear
> +	 * PTE/PUD entry, since the page is not used by other.
> +	 * So we can also free the page.
> +	 */
> +	if (memchr_inv(page_addr, PAGE_INUSE, *page_size)) {
> +		*pp = NULL;
> +		return next;
> +	}
> +
> +	if (!cpu_has_pse)
> +		pte_clear(&init_mm, addr, pte);
> +	else
> +		pmd_clear(pmd);
> +
> +	return next;
> +}
> +
> +void vmemmap_kfree(struct page *memmap, unsigned long nr_pages)
> +{
> +	unsigned long addr = (unsigned long)memmap;
> +	unsigned long end = (unsigned long)(memmap + nr_pages);
> +	unsigned long next;
> +	struct page *page;
> +	int page_size;
> +
> +	for (; addr < end; addr = next) {
> +		page = NULL;
> +		page_size = 0;
> +		next = find_and_clear_pte_page(addr, end, &page, &page_size);
> +		if (!page)
> +			continue;
> +
> +		free_pages((unsigned long)page_address(page),
> +			    get_order(page_size));
> +		__flush_tlb_one(addr);
> +	}
> +}
> +
> +void vmemmap_free_bootmem(struct page *memmap, unsigned long nr_pages)
> +{
> +	unsigned long addr = (unsigned long)memmap;
> +	unsigned long end = (unsigned long)(memmap + nr_pages);
> +	unsigned long next;
> +	struct page *page;
> +	int page_size;
> +	unsigned long magic;
> +
> +	for (; addr < end; addr = next) {
> +		page = NULL;
> +		page_size = 0;
> +		next = find_and_clear_pte_page(addr, end, &page, &page_size);
> +		if (!page)
> +			continue;
> +
> +		magic = (unsigned long) page->lru.next;
> +		if (magic == SECTION_INFO)
> +			put_page_bootmem(page);
> +		flush_tlb_kernel_range(addr, end);
> +	}
> +}
> +
>  void register_page_bootmem_memmap(unsigned long section_nr,
>  				  struct page *start_page, unsigned long size)
>  {
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 8e5a56f..42b8723 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -1642,6 +1642,8 @@ int vmemmap_populate(struct page *start_page, unsigned long pages, int node);
>  void vmemmap_populate_print_last(void);
>  void register_page_bootmem_memmap(unsigned long section_nr, struct page *map,
>  				  unsigned long size);
> +void vmemmap_kfree(struct page *memmpa, unsigned long nr_pages);
> +void vmemmap_free_bootmem(struct page *memmpa, unsigned long nr_pages);
>  
>  enum mf_flags {
>  	MF_COUNT_INCREASED = 1 << 0,
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index db9806c..03153cf 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -312,19 +312,6 @@ static int __meminit __add_section(int nid, struct zone *zone,
>  	return register_new_memory(nid, __pfn_to_section(phys_start_pfn));
>  }
>  
> -#ifdef CONFIG_SPARSEMEM_VMEMMAP
> -static int __remove_section(struct zone *zone, struct mem_section *ms)
> -{
> -	int ret = -EINVAL;
> -
> -	if (!valid_section(ms))
> -		return ret;
> -
> -	ret = unregister_memory_section(ms);
> -
> -	return ret;
> -}
> -#else
>  static int __remove_section(struct zone *zone, struct mem_section *ms)
>  {
>  	unsigned long flags;
> @@ -341,9 +328,9 @@ static int __remove_section(struct zone *zone, struct mem_section *ms)
>  	pgdat_resize_lock(pgdat, &flags);
>  	sparse_remove_one_section(zone, ms);
>  	pgdat_resize_unlock(pgdat, &flags);
> -	return 0;
> +
> +	return ret;
>  }
> -#endif
>  
>  /*
>   * Reasonably generic function for adding memory.  It is
> diff --git a/mm/sparse.c b/mm/sparse.c
> index fac95f2..ab9d755 100644
> --- a/mm/sparse.c
> +++ b/mm/sparse.c
> @@ -613,12 +613,13 @@ static inline struct page *kmalloc_section_memmap(unsigned long pnum, int nid,
>  	/* This will make the necessary allocations eventually. */
>  	return sparse_mem_map_populate(pnum, nid);
>  }
> -static void __kfree_section_memmap(struct page *memmap, unsigned long nr_pages)
> +static void __kfree_section_memmap(struct page *page, unsigned long nr_pages)
>  {
> -	return; /* XXX: Not implemented yet */
> +	vmemmap_kfree(page, nr_pages);
>  }
>  static void free_map_bootmem(struct page *page, unsigned long nr_pages)
>  {
> +	vmemmap_free_bootmem(page, nr_pages);
>  }

Hi Congyang,
	For vmemmap, nr_pages should be PAGES_PER_SECTION for free_map_bootmem(),
which is passed by free_section_usemap(), right? 
But now, nr_pages = PAGE_ALIGN(PAGES_PER_SECTION * sizeof(struct page)) >> PAGE_SHIFT.

Signed-off-by: Jianguo Wu <wujianguo@huawei.com>
---
 mm/sparse.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/mm/sparse.c b/mm/sparse.c
index fac95f2..31e5282 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -713,8 +713,12 @@ static void free_section_usemap(struct page *memmap, unsigned long *usemap)
 		struct page *memmap_page;
 		memmap_page = virt_to_page(memmap);
 
+#ifdef CONFIG_SPARSEMEM_VMEMMAP
+		nr_pages = PAGES_PER_SECTION;
+#else
 		nr_pages = PAGE_ALIGN(PAGES_PER_SECTION * sizeof(struct page))
 			>> PAGE_SHIFT;
+#endif
 
 		free_map_bootmem(memmap_page, nr_pages);
 	}
-- 
1.7.6.1

>  #else
>  static struct page *__kmalloc_section_memmap(unsigned long nr_pages)

Re: [PATCH v3 08/12] memory-hotplug: remove memmap of sparse-vmemmap

[Wen Congyang]

At 11/27/2012 01:47 PM, Jianguo Wu Wrote:
> On 2012/11/1 17:44, Wen Congyang wrote:
> 
>> From: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
>>
>> All pages of virtual mapping in removed memory cannot be freed, since some pages
>> used as PGD/PUD includes not only removed memory but also other memory. So the
>> patch checks whether page can be freed or not.
>>
>> How to check whether page can be freed or not?
>>  1. When removing memory, the page structs of the revmoved memory are filled
>>     with 0FD.
>>  2. All page structs are filled with 0xFD on PT/PMD, PT/PMD can be cleared.
>>     In this case, the page used as PT/PMD can be freed.
>>
>> Applying patch, __remove_section() of CONFIG_SPARSEMEM_VMEMMAP is integrated
>> into one. So __remove_section() of CONFIG_SPARSEMEM_VMEMMAP is deleted.
>>
>> Note:  vmemmap_kfree() and vmemmap_free_bootmem() are not implemented for ia64,
>> ppc, s390, and sparc.
>>
>> CC: David Rientjes <rientjes@google.com>
>> CC: Jiang Liu <liuj97@gmail.com>
>> CC: Len Brown <len.brown@intel.com>
>> 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>
>> CC: Wen Congyang <wency@cn.fujitsu.com>
>> Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
>> ---
>>  arch/ia64/mm/discontig.c  |   8 ++++
>>  arch/powerpc/mm/init_64.c |   8 ++++
>>  arch/s390/mm/vmem.c       |   8 ++++
>>  arch/sparc/mm/init_64.c   |   8 ++++
>>  arch/x86/mm/init_64.c     | 119 ++++++++++++++++++++++++++++++++++++++++++++++
>>  include/linux/mm.h        |   2 +
>>  mm/memory_hotplug.c       |  17 +------
>>  mm/sparse.c               |   5 +-
>>  8 files changed, 158 insertions(+), 17 deletions(-)
>>
>> diff --git a/arch/ia64/mm/discontig.c b/arch/ia64/mm/discontig.c
>> index 33943db..0d23b69 100644
>> --- a/arch/ia64/mm/discontig.c
>> +++ b/arch/ia64/mm/discontig.c
>> @@ -823,6 +823,14 @@ int __meminit vmemmap_populate(struct page *start_page,
>>  	return vmemmap_populate_basepages(start_page, size, node);
>>  }
>>  
>> +void vmemmap_kfree(struct page *memmap, unsigned long nr_pages)
>> +{
>> +}
>> +
>> +void vmemmap_free_bootmem(struct page *memmap, unsigned long nr_pages)
>> +{
>> +}
>> +
>>  void register_page_bootmem_memmap(unsigned long section_nr,
>>  				  struct page *start_page, unsigned long size)
>>  {
>> diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
>> index 6466440..df7d155 100644
>> --- a/arch/powerpc/mm/init_64.c
>> +++ b/arch/powerpc/mm/init_64.c
>> @@ -298,6 +298,14 @@ int __meminit vmemmap_populate(struct page *start_page,
>>  	return 0;
>>  }
>>  
>> +void vmemmap_kfree(struct page *memmap, unsigned long nr_pages)
>> +{
>> +}
>> +
>> +void vmemmap_free_bootmem(struct page *memmap, unsigned long nr_pages)
>> +{
>> +}
>> +
>>  void register_page_bootmem_memmap(unsigned long section_nr,
>>  				  struct page *start_page, unsigned long size)
>>  {
>> diff --git a/arch/s390/mm/vmem.c b/arch/s390/mm/vmem.c
>> index 4f4803a..ab69c34 100644
>> --- a/arch/s390/mm/vmem.c
>> +++ b/arch/s390/mm/vmem.c
>> @@ -236,6 +236,14 @@ out:
>>  	return ret;
>>  }
>>  
>> +void vmemmap_kfree(struct page *memmap, unsigned long nr_pages)
>> +{
>> +}
>> +
>> +void vmemmap_free_bootmem(struct page *memmap, unsigned long nr_pages)
>> +{
>> +}
>> +
>>  void register_page_bootmem_memmap(unsigned long section_nr,
>>  				  struct page *start_page, unsigned long size)
>>  {
>> diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c
>> index 75a984b..546855d 100644
>> --- a/arch/sparc/mm/init_64.c
>> +++ b/arch/sparc/mm/init_64.c
>> @@ -2232,6 +2232,14 @@ void __meminit vmemmap_populate_print_last(void)
>>  	}
>>  }
>>  
>> +void vmemmap_kfree(struct page *memmap, unsigned long nr_pages)
>> +{
>> +}
>> +
>> +void vmemmap_free_bootmem(struct page *memmap, unsigned long nr_pages)
>> +{
>> +}
>> +
>>  void register_page_bootmem_memmap(unsigned long section_nr,
>>  				  struct page *start_page, unsigned long size)
>>  {
>> diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
>> index 795dae3..e85626d 100644
>> --- a/arch/x86/mm/init_64.c
>> +++ b/arch/x86/mm/init_64.c
>> @@ -998,6 +998,125 @@ vmemmap_populate(struct page *start_page, unsigned long size, int node)
>>  	return 0;
>>  }
>>  
>> +#define PAGE_INUSE 0xFD
>> +
>> +unsigned long find_and_clear_pte_page(unsigned long addr, unsigned long end,
>> +			    struct page **pp, int *page_size)
>> +{
>> +	pgd_t *pgd;
>> +	pud_t *pud;
>> +	pmd_t *pmd;
>> +	pte_t *pte = NULL;
>> +	void *page_addr;
>> +	unsigned long next;
>> +
>> +	*pp = NULL;
>> +
>> +	pgd = pgd_offset_k(addr);
>> +	if (pgd_none(*pgd))
>> +		return pgd_addr_end(addr, end);
>> +
>> +	pud = pud_offset(pgd, addr);
>> +	if (pud_none(*pud))
>> +		return pud_addr_end(addr, end);
>> +
>> +	if (!cpu_has_pse) {
>> +		next = (addr + PAGE_SIZE) & PAGE_MASK;
>> +		pmd = pmd_offset(pud, addr);
>> +		if (pmd_none(*pmd))
>> +			return next;
>> +
>> +		pte = pte_offset_kernel(pmd, addr);
>> +		if (pte_none(*pte))
>> +			return next;
>> +
>> +		*page_size = PAGE_SIZE;
>> +		*pp = pte_page(*pte);
>> +	} else {
>> +		next = pmd_addr_end(addr, end);
>> +
>> +		pmd = pmd_offset(pud, addr);
>> +		if (pmd_none(*pmd))
>> +			return next;
>> +
>> +		*page_size = PMD_SIZE;
>> +		*pp = pmd_page(*pmd);
>> +	}
>> +
>> +	/*
>> +	 * Removed page structs are filled with 0xFD.
>> +	 */
>> +	memset((void *)addr, PAGE_INUSE, next - addr);
>> +
>> +	page_addr = page_address(*pp);
>> +
>> +	/*
>> +	 * Check the page is filled with 0xFD or not.
>> +	 * memchr_inv() returns the address. In this case, we cannot
>> +	 * clear PTE/PUD entry, since the page is used by other.
>> +	 * So we cannot also free the page.
>> +	 *
>> +	 * memchr_inv() returns NULL. In this case, we can clear
>> +	 * PTE/PUD entry, since the page is not used by other.
>> +	 * So we can also free the page.
>> +	 */
>> +	if (memchr_inv(page_addr, PAGE_INUSE, *page_size)) {
>> +		*pp = NULL;
>> +		return next;
>> +	}
>> +
>> +	if (!cpu_has_pse)
>> +		pte_clear(&init_mm, addr, pte);
>> +	else
>> +		pmd_clear(pmd);
>> +
>> +	return next;
>> +}
>> +
>> +void vmemmap_kfree(struct page *memmap, unsigned long nr_pages)
>> +{
>> +	unsigned long addr = (unsigned long)memmap;
>> +	unsigned long end = (unsigned long)(memmap + nr_pages);
>> +	unsigned long next;
>> +	struct page *page;
>> +	int page_size;
>> +
>> +	for (; addr < end; addr = next) {
>> +		page = NULL;
>> +		page_size = 0;
>> +		next = find_and_clear_pte_page(addr, end, &page, &page_size);
>> +		if (!page)
>> +			continue;
>> +
>> +		free_pages((unsigned long)page_address(page),
>> +			    get_order(page_size));
>> +		__flush_tlb_one(addr);
>> +	}
>> +}
>> +
>> +void vmemmap_free_bootmem(struct page *memmap, unsigned long nr_pages)
>> +{
>> +	unsigned long addr = (unsigned long)memmap;
>> +	unsigned long end = (unsigned long)(memmap + nr_pages);
>> +	unsigned long next;
>> +	struct page *page;
>> +	int page_size;
>> +	unsigned long magic;
>> +
>> +	for (; addr < end; addr = next) {
>> +		page = NULL;
>> +		page_size = 0;
>> +		next = find_and_clear_pte_page(addr, end, &page, &page_size);
>> +		if (!page)
>> +			continue;
>> +
>> +		magic = (unsigned long) page->lru.next;
>> +		if (magic == SECTION_INFO)
>> +			put_page_bootmem(page);
>> +		flush_tlb_kernel_range(addr, end);
>> +	}
>> +}
>> +
>>  void register_page_bootmem_memmap(unsigned long section_nr,
>>  				  struct page *start_page, unsigned long size)
>>  {
>> diff --git a/include/linux/mm.h b/include/linux/mm.h
>> index 8e5a56f..42b8723 100644
>> --- a/include/linux/mm.h
>> +++ b/include/linux/mm.h
>> @@ -1642,6 +1642,8 @@ int vmemmap_populate(struct page *start_page, unsigned long pages, int node);
>>  void vmemmap_populate_print_last(void);
>>  void register_page_bootmem_memmap(unsigned long section_nr, struct page *map,
>>  				  unsigned long size);
>> +void vmemmap_kfree(struct page *memmpa, unsigned long nr_pages);
>> +void vmemmap_free_bootmem(struct page *memmpa, unsigned long nr_pages);
>>  
>>  enum mf_flags {
>>  	MF_COUNT_INCREASED = 1 << 0,
>> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
>> index db9806c..03153cf 100644
>> --- a/mm/memory_hotplug.c
>> +++ b/mm/memory_hotplug.c
>> @@ -312,19 +312,6 @@ static int __meminit __add_section(int nid, struct zone *zone,
>>  	return register_new_memory(nid, __pfn_to_section(phys_start_pfn));
>>  }
>>  
>> -#ifdef CONFIG_SPARSEMEM_VMEMMAP
>> -static int __remove_section(struct zone *zone, struct mem_section *ms)
>> -{
>> -	int ret = -EINVAL;
>> -
>> -	if (!valid_section(ms))
>> -		return ret;
>> -
>> -	ret = unregister_memory_section(ms);
>> -
>> -	return ret;
>> -}
>> -#else
>>  static int __remove_section(struct zone *zone, struct mem_section *ms)
>>  {
>>  	unsigned long flags;
>> @@ -341,9 +328,9 @@ static int __remove_section(struct zone *zone, struct mem_section *ms)
>>  	pgdat_resize_lock(pgdat, &flags);
>>  	sparse_remove_one_section(zone, ms);
>>  	pgdat_resize_unlock(pgdat, &flags);
>> -	return 0;
>> +
>> +	return ret;
>>  }
>> -#endif
>>  
>>  /*
>>   * Reasonably generic function for adding memory.  It is
>> diff --git a/mm/sparse.c b/mm/sparse.c
>> index fac95f2..ab9d755 100644
>> --- a/mm/sparse.c
>> +++ b/mm/sparse.c
>> @@ -613,12 +613,13 @@ static inline struct page *kmalloc_section_memmap(unsigned long pnum, int nid,
>>  	/* This will make the necessary allocations eventually. */
>>  	return sparse_mem_map_populate(pnum, nid);
>>  }
>> -static void __kfree_section_memmap(struct page *memmap, unsigned long nr_pages)
>> +static void __kfree_section_memmap(struct page *page, unsigned long nr_pages)
>>  {
>> -	return; /* XXX: Not implemented yet */
>> +	vmemmap_kfree(page, nr_pages);
>>  }
>>  static void free_map_bootmem(struct page *page, unsigned long nr_pages)
>>  {
>> +	vmemmap_free_bootmem(page, nr_pages);
>>  }
> 
> Hi Congyang,
> 	For vmemmap, nr_pages should be PAGES_PER_SECTION for free_map_bootmem(),
> which is passed by free_section_usemap(), right? 

Yes, you are right. I will merge it into my patchset.

I will sent the new patchset later today.

Thanks
Wen Congyang

> But now, nr_pages = PAGE_ALIGN(PAGES_PER_SECTION * sizeof(struct page)) >> PAGE_SHIFT.
> 
> Signed-off-by: Jianguo Wu <wujianguo@huawei.com>
> ---
>  mm/sparse.c |    4 ++++
>  1 files changed, 4 insertions(+), 0 deletions(-)
> 
> diff --git a/mm/sparse.c b/mm/sparse.c
> index fac95f2..31e5282 100644
> --- a/mm/sparse.c
> +++ b/mm/sparse.c
> @@ -713,8 +713,12 @@ static void free_section_usemap(struct page *memmap, unsigned long *usemap)
>  		struct page *memmap_page;
>  		memmap_page = virt_to_page(memmap);
>  
> +#ifdef CONFIG_SPARSEMEM_VMEMMAP
> +		nr_pages = PAGES_PER_SECTION;
> +#else
>  		nr_pages = PAGE_ALIGN(PAGES_PER_SECTION * sizeof(struct page))
>  			>> PAGE_SHIFT;
> +#endif
>  
>  		free_map_bootmem(memmap_page, nr_pages);
>  	}

Re: [PATCH v3 08/12] memory-hotplug: remove memmap of sparse-vmemmap

[Wen Congyang]

At 11/27/2012 01:47 PM, Jianguo Wu Wrote:
> On 2012/11/1 17:44, Wen Congyang wrote:
> 
>> From: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
>>
>> All pages of virtual mapping in removed memory cannot be freed, since some pages
>> used as PGD/PUD includes not only removed memory but also other memory. So the
>> patch checks whether page can be freed or not.
>>
>> How to check whether page can be freed or not?
>>  1. When removing memory, the page structs of the revmoved memory are filled
>>     with 0FD.
>>  2. All page structs are filled with 0xFD on PT/PMD, PT/PMD can be cleared.
>>     In this case, the page used as PT/PMD can be freed.
>>
>> Applying patch, __remove_section() of CONFIG_SPARSEMEM_VMEMMAP is integrated
>> into one. So __remove_section() of CONFIG_SPARSEMEM_VMEMMAP is deleted.
>>
>> Note:  vmemmap_kfree() and vmemmap_free_bootmem() are not implemented for ia64,
>> ppc, s390, and sparc.
>>
>> CC: David Rientjes <rientjes@google.com>
>> CC: Jiang Liu <liuj97@gmail.com>
>> CC: Len Brown <len.brown@intel.com>
>> 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>
>> CC: Wen Congyang <wency@cn.fujitsu.com>
>> Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
>> ---
>>  arch/ia64/mm/discontig.c  |   8 ++++
>>  arch/powerpc/mm/init_64.c |   8 ++++
>>  arch/s390/mm/vmem.c       |   8 ++++
>>  arch/sparc/mm/init_64.c   |   8 ++++
>>  arch/x86/mm/init_64.c     | 119 ++++++++++++++++++++++++++++++++++++++++++++++
>>  include/linux/mm.h        |   2 +
>>  mm/memory_hotplug.c       |  17 +------
>>  mm/sparse.c               |   5 +-
>>  8 files changed, 158 insertions(+), 17 deletions(-)
>>
>> diff --git a/arch/ia64/mm/discontig.c b/arch/ia64/mm/discontig.c
>> index 33943db..0d23b69 100644
>> --- a/arch/ia64/mm/discontig.c
>> +++ b/arch/ia64/mm/discontig.c
>> @@ -823,6 +823,14 @@ int __meminit vmemmap_populate(struct page *start_page,
>>  	return vmemmap_populate_basepages(start_page, size, node);
>>  }
>>  
>> +void vmemmap_kfree(struct page *memmap, unsigned long nr_pages)
>> +{
>> +}
>> +
>> +void vmemmap_free_bootmem(struct page *memmap, unsigned long nr_pages)
>> +{
>> +}
>> +
>>  void register_page_bootmem_memmap(unsigned long section_nr,
>>  				  struct page *start_page, unsigned long size)
>>  {
>> diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
>> index 6466440..df7d155 100644
>> --- a/arch/powerpc/mm/init_64.c
>> +++ b/arch/powerpc/mm/init_64.c
>> @@ -298,6 +298,14 @@ int __meminit vmemmap_populate(struct page *start_page,
>>  	return 0;
>>  }
>>  
>> +void vmemmap_kfree(struct page *memmap, unsigned long nr_pages)
>> +{
>> +}
>> +
>> +void vmemmap_free_bootmem(struct page *memmap, unsigned long nr_pages)
>> +{
>> +}
>> +
>>  void register_page_bootmem_memmap(unsigned long section_nr,
>>  				  struct page *start_page, unsigned long size)
>>  {
>> diff --git a/arch/s390/mm/vmem.c b/arch/s390/mm/vmem.c
>> index 4f4803a..ab69c34 100644
>> --- a/arch/s390/mm/vmem.c
>> +++ b/arch/s390/mm/vmem.c
>> @@ -236,6 +236,14 @@ out:
>>  	return ret;
>>  }
>>  
>> +void vmemmap_kfree(struct page *memmap, unsigned long nr_pages)
>> +{
>> +}
>> +
>> +void vmemmap_free_bootmem(struct page *memmap, unsigned long nr_pages)
>> +{
>> +}
>> +
>>  void register_page_bootmem_memmap(unsigned long section_nr,
>>  				  struct page *start_page, unsigned long size)
>>  {
>> diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c
>> index 75a984b..546855d 100644
>> --- a/arch/sparc/mm/init_64.c
>> +++ b/arch/sparc/mm/init_64.c
>> @@ -2232,6 +2232,14 @@ void __meminit vmemmap_populate_print_last(void)
>>  	}
>>  }
>>  
>> +void vmemmap_kfree(struct page *memmap, unsigned long nr_pages)
>> +{
>> +}
>> +
>> +void vmemmap_free_bootmem(struct page *memmap, unsigned long nr_pages)
>> +{
>> +}
>> +
>>  void register_page_bootmem_memmap(unsigned long section_nr,
>>  				  struct page *start_page, unsigned long size)
>>  {
>> diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
>> index 795dae3..e85626d 100644
>> --- a/arch/x86/mm/init_64.c
>> +++ b/arch/x86/mm/init_64.c
>> @@ -998,6 +998,125 @@ vmemmap_populate(struct page *start_page, unsigned long size, int node)
>>  	return 0;
>>  }
>>  
>> +#define PAGE_INUSE 0xFD
>> +
>> +unsigned long find_and_clear_pte_page(unsigned long addr, unsigned long end,
>> +			    struct page **pp, int *page_size)
>> +{
>> +	pgd_t *pgd;
>> +	pud_t *pud;
>> +	pmd_t *pmd;
>> +	pte_t *pte = NULL;
>> +	void *page_addr;
>> +	unsigned long next;
>> +
>> +	*pp = NULL;
>> +
>> +	pgd = pgd_offset_k(addr);
>> +	if (pgd_none(*pgd))
>> +		return pgd_addr_end(addr, end);
>> +
>> +	pud = pud_offset(pgd, addr);
>> +	if (pud_none(*pud))
>> +		return pud_addr_end(addr, end);
>> +
>> +	if (!cpu_has_pse) {
>> +		next = (addr + PAGE_SIZE) & PAGE_MASK;
>> +		pmd = pmd_offset(pud, addr);
>> +		if (pmd_none(*pmd))
>> +			return next;
>> +
>> +		pte = pte_offset_kernel(pmd, addr);
>> +		if (pte_none(*pte))
>> +			return next;
>> +
>> +		*page_size = PAGE_SIZE;
>> +		*pp = pte_page(*pte);
>> +	} else {
>> +		next = pmd_addr_end(addr, end);
>> +
>> +		pmd = pmd_offset(pud, addr);
>> +		if (pmd_none(*pmd))
>> +			return next;
>> +
>> +		*page_size = PMD_SIZE;
>> +		*pp = pmd_page(*pmd);
>> +	}
>> +
>> +	/*
>> +	 * Removed page structs are filled with 0xFD.
>> +	 */
>> +	memset((void *)addr, PAGE_INUSE, next - addr);
>> +
>> +	page_addr = page_address(*pp);
>> +
>> +	/*
>> +	 * Check the page is filled with 0xFD or not.
>> +	 * memchr_inv() returns the address. In this case, we cannot
>> +	 * clear PTE/PUD entry, since the page is used by other.
>> +	 * So we cannot also free the page.
>> +	 *
>> +	 * memchr_inv() returns NULL. In this case, we can clear
>> +	 * PTE/PUD entry, since the page is not used by other.
>> +	 * So we can also free the page.
>> +	 */
>> +	if (memchr_inv(page_addr, PAGE_INUSE, *page_size)) {
>> +		*pp = NULL;
>> +		return next;
>> +	}
>> +
>> +	if (!cpu_has_pse)
>> +		pte_clear(&init_mm, addr, pte);
>> +	else
>> +		pmd_clear(pmd);
>> +
>> +	return next;
>> +}
>> +
>> +void vmemmap_kfree(struct page *memmap, unsigned long nr_pages)
>> +{
>> +	unsigned long addr = (unsigned long)memmap;
>> +	unsigned long end = (unsigned long)(memmap + nr_pages);
>> +	unsigned long next;
>> +	struct page *page;
>> +	int page_size;
>> +
>> +	for (; addr < end; addr = next) {
>> +		page = NULL;
>> +		page_size = 0;
>> +		next = find_and_clear_pte_page(addr, end, &page, &page_size);
>> +		if (!page)
>> +			continue;
>> +
>> +		free_pages((unsigned long)page_address(page),
>> +			    get_order(page_size));
>> +		__flush_tlb_one(addr);
>> +	}
>> +}
>> +
>> +void vmemmap_free_bootmem(struct page *memmap, unsigned long nr_pages)
>> +{
>> +	unsigned long addr = (unsigned long)memmap;
>> +	unsigned long end = (unsigned long)(memmap + nr_pages);
>> +	unsigned long next;
>> +	struct page *page;
>> +	int page_size;
>> +	unsigned long magic;
>> +
>> +	for (; addr < end; addr = next) {
>> +		page = NULL;
>> +		page_size = 0;
>> +		next = find_and_clear_pte_page(addr, end, &page, &page_size);
>> +		if (!page)
>> +			continue;
>> +
>> +		magic = (unsigned long) page->lru.next;
>> +		if (magic == SECTION_INFO)
>> +			put_page_bootmem(page);
>> +		flush_tlb_kernel_range(addr, end);
>> +	}
>> +}
>> +
>>  void register_page_bootmem_memmap(unsigned long section_nr,
>>  				  struct page *start_page, unsigned long size)
>>  {
>> diff --git a/include/linux/mm.h b/include/linux/mm.h
>> index 8e5a56f..42b8723 100644
>> --- a/include/linux/mm.h
>> +++ b/include/linux/mm.h
>> @@ -1642,6 +1642,8 @@ int vmemmap_populate(struct page *start_page, unsigned long pages, int node);
>>  void vmemmap_populate_print_last(void);
>>  void register_page_bootmem_memmap(unsigned long section_nr, struct page *map,
>>  				  unsigned long size);
>> +void vmemmap_kfree(struct page *memmpa, unsigned long nr_pages);
>> +void vmemmap_free_bootmem(struct page *memmpa, unsigned long nr_pages);
>>  
>>  enum mf_flags {
>>  	MF_COUNT_INCREASED = 1 << 0,
>> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
>> index db9806c..03153cf 100644
>> --- a/mm/memory_hotplug.c
>> +++ b/mm/memory_hotplug.c
>> @@ -312,19 +312,6 @@ static int __meminit __add_section(int nid, struct zone *zone,
>>  	return register_new_memory(nid, __pfn_to_section(phys_start_pfn));
>>  }
>>  
>> -#ifdef CONFIG_SPARSEMEM_VMEMMAP
>> -static int __remove_section(struct zone *zone, struct mem_section *ms)
>> -{
>> -	int ret = -EINVAL;
>> -
>> -	if (!valid_section(ms))
>> -		return ret;
>> -
>> -	ret = unregister_memory_section(ms);
>> -
>> -	return ret;
>> -}
>> -#else
>>  static int __remove_section(struct zone *zone, struct mem_section *ms)
>>  {
>>  	unsigned long flags;
>> @@ -341,9 +328,9 @@ static int __remove_section(struct zone *zone, struct mem_section *ms)
>>  	pgdat_resize_lock(pgdat, &flags);
>>  	sparse_remove_one_section(zone, ms);
>>  	pgdat_resize_unlock(pgdat, &flags);
>> -	return 0;
>> +
>> +	return ret;
>>  }
>> -#endif
>>  
>>  /*
>>   * Reasonably generic function for adding memory.  It is
>> diff --git a/mm/sparse.c b/mm/sparse.c
>> index fac95f2..ab9d755 100644
>> --- a/mm/sparse.c
>> +++ b/mm/sparse.c
>> @@ -613,12 +613,13 @@ static inline struct page *kmalloc_section_memmap(unsigned long pnum, int nid,
>>  	/* This will make the necessary allocations eventually. */
>>  	return sparse_mem_map_populate(pnum, nid);
>>  }
>> -static void __kfree_section_memmap(struct page *memmap, unsigned long nr_pages)
>> +static void __kfree_section_memmap(struct page *page, unsigned long nr_pages)
>>  {
>> -	return; /* XXX: Not implemented yet */
>> +	vmemmap_kfree(page, nr_pages);
>>  }
>>  static void free_map_bootmem(struct page *page, unsigned long nr_pages)
>>  {
>> +	vmemmap_free_bootmem(page, nr_pages);
>>  }
> 
> Hi Congyang,
> 	For vmemmap, nr_pages should be PAGES_PER_SECTION for free_map_bootmem(),
> which is passed by free_section_usemap(), right? 
> But now, nr_pages = PAGE_ALIGN(PAGES_PER_SECTION * sizeof(struct page)) >> PAGE_SHIFT.
> 
> Signed-off-by: Jianguo Wu <wujianguo@huawei.com>
> ---
>  mm/sparse.c |    4 ++++
>  1 files changed, 4 insertions(+), 0 deletions(-)
> 
> diff --git a/mm/sparse.c b/mm/sparse.c
> index fac95f2..31e5282 100644
> --- a/mm/sparse.c
> +++ b/mm/sparse.c
> @@ -713,8 +713,12 @@ static void free_section_usemap(struct page *memmap, unsigned long *usemap)
>  		struct page *memmap_page;
>  		memmap_page = virt_to_page(memmap);
>  
> +#ifdef CONFIG_SPARSEMEM_VMEMMAP
> +		nr_pages = PAGES_PER_SECTION;
> +#else
>  		nr_pages = PAGE_ALIGN(PAGES_PER_SECTION * sizeof(struct page))
>  			>> PAGE_SHIFT;
> +#endif

Hmm, to avoid using ifdef, I think we can pass PAGE_PER_SECTION to free_map_bootmem(),
and calculate how many pages is used to store struct page.

Thanks
Wen Congyang

>  
>  		free_map_bootmem(memmap_page, nr_pages);
>  	}

Re: [PATCH v3 08/12] memory-hotplug: remove memmap of sparse-vmemmap

[Jianguo Wu]

On 2012/11/27 14:49, Wen Congyang wrote:

> At 11/27/2012 01:47 PM, Jianguo Wu Wrote:
>> On 2012/11/1 17:44, Wen Congyang wrote:
>>
>>> From: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
>>>
>>> All pages of virtual mapping in removed memory cannot be freed, since some pages
>>> used as PGD/PUD includes not only removed memory but also other memory. So the
>>> patch checks whether page can be freed or not.
>>>
>>> How to check whether page can be freed or not?
>>>  1. When removing memory, the page structs of the revmoved memory are filled
>>>     with 0FD.
>>>  2. All page structs are filled with 0xFD on PT/PMD, PT/PMD can be cleared.
>>>     In this case, the page used as PT/PMD can be freed.
>>>
>>> Applying patch, __remove_section() of CONFIG_SPARSEMEM_VMEMMAP is integrated
>>> into one. So __remove_section() of CONFIG_SPARSEMEM_VMEMMAP is deleted.
>>>
>>> Note:  vmemmap_kfree() and vmemmap_free_bootmem() are not implemented for ia64,
>>> ppc, s390, and sparc.
>>>
>>> CC: David Rientjes <rientjes@google.com>
>>> CC: Jiang Liu <liuj97@gmail.com>
>>> CC: Len Brown <len.brown@intel.com>
>>> 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>
>>> CC: Wen Congyang <wency@cn.fujitsu.com>
>>> Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
>>> ---
>>>  arch/ia64/mm/discontig.c  |   8 ++++
>>>  arch/powerpc/mm/init_64.c |   8 ++++
>>>  arch/s390/mm/vmem.c       |   8 ++++
>>>  arch/sparc/mm/init_64.c   |   8 ++++
>>>  arch/x86/mm/init_64.c     | 119 ++++++++++++++++++++++++++++++++++++++++++++++
>>>  include/linux/mm.h        |   2 +
>>>  mm/memory_hotplug.c       |  17 +------
>>>  mm/sparse.c               |   5 +-
>>>  8 files changed, 158 insertions(+), 17 deletions(-)
>>>
>>> diff --git a/arch/ia64/mm/discontig.c b/arch/ia64/mm/discontig.c
>>> index 33943db..0d23b69 100644
>>> --- a/arch/ia64/mm/discontig.c
>>> +++ b/arch/ia64/mm/discontig.c
>>> @@ -823,6 +823,14 @@ int __meminit vmemmap_populate(struct page *start_page,
>>>  	return vmemmap_populate_basepages(start_page, size, node);
>>>  }
>>>  
>>> +void vmemmap_kfree(struct page *memmap, unsigned long nr_pages)
>>> +{
>>> +}
>>> +
>>> +void vmemmap_free_bootmem(struct page *memmap, unsigned long nr_pages)
>>> +{
>>> +}
>>> +
>>>  void register_page_bootmem_memmap(unsigned long section_nr,
>>>  				  struct page *start_page, unsigned long size)
>>>  {
>>> diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
>>> index 6466440..df7d155 100644
>>> --- a/arch/powerpc/mm/init_64.c
>>> +++ b/arch/powerpc/mm/init_64.c
>>> @@ -298,6 +298,14 @@ int __meminit vmemmap_populate(struct page *start_page,
>>>  	return 0;
>>>  }
>>>  
>>> +void vmemmap_kfree(struct page *memmap, unsigned long nr_pages)
>>> +{
>>> +}
>>> +
>>> +void vmemmap_free_bootmem(struct page *memmap, unsigned long nr_pages)
>>> +{
>>> +}
>>> +
>>>  void register_page_bootmem_memmap(unsigned long section_nr,
>>>  				  struct page *start_page, unsigned long size)
>>>  {
>>> diff --git a/arch/s390/mm/vmem.c b/arch/s390/mm/vmem.c
>>> index 4f4803a..ab69c34 100644
>>> --- a/arch/s390/mm/vmem.c
>>> +++ b/arch/s390/mm/vmem.c
>>> @@ -236,6 +236,14 @@ out:
>>>  	return ret;
>>>  }
>>>  
>>> +void vmemmap_kfree(struct page *memmap, unsigned long nr_pages)
>>> +{
>>> +}
>>> +
>>> +void vmemmap_free_bootmem(struct page *memmap, unsigned long nr_pages)
>>> +{
>>> +}
>>> +
>>>  void register_page_bootmem_memmap(unsigned long section_nr,
>>>  				  struct page *start_page, unsigned long size)
>>>  {
>>> diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c
>>> index 75a984b..546855d 100644
>>> --- a/arch/sparc/mm/init_64.c
>>> +++ b/arch/sparc/mm/init_64.c
>>> @@ -2232,6 +2232,14 @@ void __meminit vmemmap_populate_print_last(void)
>>>  	}
>>>  }
>>>  
>>> +void vmemmap_kfree(struct page *memmap, unsigned long nr_pages)
>>> +{
>>> +}
>>> +
>>> +void vmemmap_free_bootmem(struct page *memmap, unsigned long nr_pages)
>>> +{
>>> +}
>>> +
>>>  void register_page_bootmem_memmap(unsigned long section_nr,
>>>  				  struct page *start_page, unsigned long size)
>>>  {
>>> diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
>>> index 795dae3..e85626d 100644
>>> --- a/arch/x86/mm/init_64.c
>>> +++ b/arch/x86/mm/init_64.c
>>> @@ -998,6 +998,125 @@ vmemmap_populate(struct page *start_page, unsigned long size, int node)
>>>  	return 0;
>>>  }
>>>  
>>> +#define PAGE_INUSE 0xFD
>>> +
>>> +unsigned long find_and_clear_pte_page(unsigned long addr, unsigned long end,
>>> +			    struct page **pp, int *page_size)
>>> +{
>>> +	pgd_t *pgd;
>>> +	pud_t *pud;
>>> +	pmd_t *pmd;
>>> +	pte_t *pte = NULL;
>>> +	void *page_addr;
>>> +	unsigned long next;
>>> +
>>> +	*pp = NULL;
>>> +
>>> +	pgd = pgd_offset_k(addr);
>>> +	if (pgd_none(*pgd))
>>> +		return pgd_addr_end(addr, end);
>>> +
>>> +	pud = pud_offset(pgd, addr);
>>> +	if (pud_none(*pud))
>>> +		return pud_addr_end(addr, end);
>>> +
>>> +	if (!cpu_has_pse) {
>>> +		next = (addr + PAGE_SIZE) & PAGE_MASK;
>>> +		pmd = pmd_offset(pud, addr);
>>> +		if (pmd_none(*pmd))
>>> +			return next;
>>> +
>>> +		pte = pte_offset_kernel(pmd, addr);
>>> +		if (pte_none(*pte))
>>> +			return next;
>>> +
>>> +		*page_size = PAGE_SIZE;
>>> +		*pp = pte_page(*pte);
>>> +	} else {
>>> +		next = pmd_addr_end(addr, end);
>>> +
>>> +		pmd = pmd_offset(pud, addr);
>>> +		if (pmd_none(*pmd))
>>> +			return next;
>>> +
>>> +		*page_size = PMD_SIZE;
>>> +		*pp = pmd_page(*pmd);
>>> +	}
>>> +
>>> +	/*
>>> +	 * Removed page structs are filled with 0xFD.
>>> +	 */
>>> +	memset((void *)addr, PAGE_INUSE, next - addr);
>>> +
>>> +	page_addr = page_address(*pp);
>>> +
>>> +	/*
>>> +	 * Check the page is filled with 0xFD or not.
>>> +	 * memchr_inv() returns the address. In this case, we cannot
>>> +	 * clear PTE/PUD entry, since the page is used by other.
>>> +	 * So we cannot also free the page.
>>> +	 *
>>> +	 * memchr_inv() returns NULL. In this case, we can clear
>>> +	 * PTE/PUD entry, since the page is not used by other.
>>> +	 * So we can also free the page.
>>> +	 */
>>> +	if (memchr_inv(page_addr, PAGE_INUSE, *page_size)) {
>>> +		*pp = NULL;
>>> +		return next;
>>> +	}
>>> +
>>> +	if (!cpu_has_pse)
>>> +		pte_clear(&init_mm, addr, pte);
>>> +	else
>>> +		pmd_clear(pmd);
>>> +
>>> +	return next;
>>> +}
>>> +
>>> +void vmemmap_kfree(struct page *memmap, unsigned long nr_pages)
>>> +{
>>> +	unsigned long addr = (unsigned long)memmap;
>>> +	unsigned long end = (unsigned long)(memmap + nr_pages);
>>> +	unsigned long next;
>>> +	struct page *page;
>>> +	int page_size;
>>> +
>>> +	for (; addr < end; addr = next) {
>>> +		page = NULL;
>>> +		page_size = 0;
>>> +		next = find_and_clear_pte_page(addr, end, &page, &page_size);
>>> +		if (!page)
>>> +			continue;
>>> +
>>> +		free_pages((unsigned long)page_address(page),
>>> +			    get_order(page_size));
>>> +		__flush_tlb_one(addr);
>>> +	}
>>> +}
>>> +
>>> +void vmemmap_free_bootmem(struct page *memmap, unsigned long nr_pages)
>>> +{
>>> +	unsigned long addr = (unsigned long)memmap;
>>> +	unsigned long end = (unsigned long)(memmap + nr_pages);
>>> +	unsigned long next;
>>> +	struct page *page;
>>> +	int page_size;
>>> +	unsigned long magic;
>>> +
>>> +	for (; addr < end; addr = next) {
>>> +		page = NULL;
>>> +		page_size = 0;
>>> +		next = find_and_clear_pte_page(addr, end, &page, &page_size);
>>> +		if (!page)
>>> +			continue;
>>> +
>>> +		magic = (unsigned long) page->lru.next;
>>> +		if (magic == SECTION_INFO)
>>> +			put_page_bootmem(page);
>>> +		flush_tlb_kernel_range(addr, end);
>>> +	}
>>> +}
>>> +
>>>  void register_page_bootmem_memmap(unsigned long section_nr,
>>>  				  struct page *start_page, unsigned long size)
>>>  {
>>> diff --git a/include/linux/mm.h b/include/linux/mm.h
>>> index 8e5a56f..42b8723 100644
>>> --- a/include/linux/mm.h
>>> +++ b/include/linux/mm.h
>>> @@ -1642,6 +1642,8 @@ int vmemmap_populate(struct page *start_page, unsigned long pages, int node);
>>>  void vmemmap_populate_print_last(void);
>>>  void register_page_bootmem_memmap(unsigned long section_nr, struct page *map,
>>>  				  unsigned long size);
>>> +void vmemmap_kfree(struct page *memmpa, unsigned long nr_pages);
>>> +void vmemmap_free_bootmem(struct page *memmpa, unsigned long nr_pages);
>>>  
>>>  enum mf_flags {
>>>  	MF_COUNT_INCREASED = 1 << 0,
>>> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
>>> index db9806c..03153cf 100644
>>> --- a/mm/memory_hotplug.c
>>> +++ b/mm/memory_hotplug.c
>>> @@ -312,19 +312,6 @@ static int __meminit __add_section(int nid, struct zone *zone,
>>>  	return register_new_memory(nid, __pfn_to_section(phys_start_pfn));
>>>  }
>>>  
>>> -#ifdef CONFIG_SPARSEMEM_VMEMMAP
>>> -static int __remove_section(struct zone *zone, struct mem_section *ms)
>>> -{
>>> -	int ret = -EINVAL;
>>> -
>>> -	if (!valid_section(ms))
>>> -		return ret;
>>> -
>>> -	ret = unregister_memory_section(ms);
>>> -
>>> -	return ret;
>>> -}
>>> -#else
>>>  static int __remove_section(struct zone *zone, struct mem_section *ms)
>>>  {
>>>  	unsigned long flags;
>>> @@ -341,9 +328,9 @@ static int __remove_section(struct zone *zone, struct mem_section *ms)
>>>  	pgdat_resize_lock(pgdat, &flags);
>>>  	sparse_remove_one_section(zone, ms);
>>>  	pgdat_resize_unlock(pgdat, &flags);
>>> -	return 0;
>>> +
>>> +	return ret;
>>>  }
>>> -#endif
>>>  
>>>  /*
>>>   * Reasonably generic function for adding memory.  It is
>>> diff --git a/mm/sparse.c b/mm/sparse.c
>>> index fac95f2..ab9d755 100644
>>> --- a/mm/sparse.c
>>> +++ b/mm/sparse.c
>>> @@ -613,12 +613,13 @@ static inline struct page *kmalloc_section_memmap(unsigned long pnum, int nid,
>>>  	/* This will make the necessary allocations eventually. */
>>>  	return sparse_mem_map_populate(pnum, nid);
>>>  }
>>> -static void __kfree_section_memmap(struct page *memmap, unsigned long nr_pages)
>>> +static void __kfree_section_memmap(struct page *page, unsigned long nr_pages)
>>>  {
>>> -	return; /* XXX: Not implemented yet */
>>> +	vmemmap_kfree(page, nr_pages);
>>>  }
>>>  static void free_map_bootmem(struct page *page, unsigned long nr_pages)
>>>  {
>>> +	vmemmap_free_bootmem(page, nr_pages);
>>>  }
>>
>> Hi Congyang,
>> 	For vmemmap, nr_pages should be PAGES_PER_SECTION for free_map_bootmem(),
>> which is passed by free_section_usemap(), right? 
>> But now, nr_pages = PAGE_ALIGN(PAGES_PER_SECTION * sizeof(struct page)) >> PAGE_SHIFT.
>>
>> Signed-off-by: Jianguo Wu <wujianguo@huawei.com>
>> ---
>>  mm/sparse.c |    4 ++++
>>  1 files changed, 4 insertions(+), 0 deletions(-)
>>
>> diff --git a/mm/sparse.c b/mm/sparse.c
>> index fac95f2..31e5282 100644
>> --- a/mm/sparse.c
>> +++ b/mm/sparse.c
>> @@ -713,8 +713,12 @@ static void free_section_usemap(struct page *memmap, unsigned long *usemap)
>>  		struct page *memmap_page;
>>  		memmap_page = virt_to_page(memmap);
>>  
>> +#ifdef CONFIG_SPARSEMEM_VMEMMAP
>> +		nr_pages = PAGES_PER_SECTION;
>> +#else
>>  		nr_pages = PAGE_ALIGN(PAGES_PER_SECTION * sizeof(struct page))
>>  			>> PAGE_SHIFT;
>> +#endif
> 
> Hmm, to avoid using ifdef, I think we can pass PAGE_PER_SECTION to free_map_bootmem(),
> and calculate how many pages is used to store struct page.
> 

yes, it is ugly to use ifdef. Or we can remove parameter--nr_pages of free_map_bootmem(),
and calculate nr_pages in free_map_bootmem() directly.

> Thanks
> Wen Congyang
> 
>>  
>>  		free_map_bootmem(memmap_page, nr_pages);
>>  	}
> 
> 
> .
> 

[PATCH v3 09/12] memory-hotplug: remove page table of x86_64 architecture

[Wen Congyang]

For hot removing memory, we sholud remove page table about the memory.
So the patch searches a page table about the removed memory, and clear
page table.

CC: David Rientjes <rientjes@google.com>
CC: Jiang Liu <liuj97@gmail.com>
CC: Len Brown <len.brown@intel.com>
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>
CC: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Jianguo Wu <wujianguo@huawei.com>
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
---
 arch/x86/include/asm/pgtable_types.h |   1 +
 arch/x86/mm/init_64.c                | 231 +++++++++++++++++++++++++++++++++++
 arch/x86/mm/pageattr.c               |  47 +++----
 3 files changed, 257 insertions(+), 22 deletions(-)

diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h
index ec8a1fc..fb0c24d 100644
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -332,6 +332,7 @@ static inline void update_page_count(int level, unsigned long pages) { }
  * as a pte too.
  */
 extern pte_t *lookup_address(unsigned long address, unsigned int *level);
+extern int __split_large_page(pte_t *kpte, unsigned long address, pte_t *pbase);
 
 #endif	/* !__ASSEMBLY__ */
 
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index e85626d..23d932a 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -680,6 +680,235 @@ int arch_add_memory(int nid, u64 start, u64 size)
 }
 EXPORT_SYMBOL_GPL(arch_add_memory);
 
+static inline void free_pagetable(struct page *page)
+{
+	struct zone *zone;
+	bool bootmem = false;
+
+	/* bootmem page has reserved flag */
+	if (PageReserved(page)) {
+		__ClearPageReserved(page);
+		bootmem = true;
+	}
+
+	__free_page(page);
+
+	if (bootmem) {
+		zone = page_zone(page);
+		zone_span_writelock(zone);
+		zone->present_pages++;
+		zone_span_writeunlock(zone);
+		totalram_pages++;
+	}
+}
+
+static void free_pte_table(pte_t *pte_start, pmd_t *pmd)
+{
+	pte_t *pte;
+	int i;
+
+	for (i = 0; i < PTRS_PER_PTE; i++) {
+		pte = pte_start + i;
+		if (pte_val(*pte))
+			return;
+	}
+
+	/* free a pte talbe */
+	free_pagetable(pmd_page(*pmd));
+	pmd_clear(pmd);
+}
+
+static void free_pmd_table(pmd_t *pmd_start, pud_t *pud)
+{
+	pmd_t *pmd;
+	int i;
+
+	for (i = 0; i < PTRS_PER_PMD; i++) {
+		pmd = pmd_start + i;
+		if (pmd_val(*pmd))
+			return;
+	}
+
+	/* free a pmd talbe */
+	free_pagetable(pud_page(*pud));
+	pud_clear(pud);
+}
+
+/* return true if pgd is changed, otherwise return false */
+static bool free_pud_table(pud_t *pud_start, pgd_t *pgd)
+{
+	pud_t *pud;
+	int i;
+
+	for (i = 0; i < PTRS_PER_PUD; i++) {
+		pud = pud_start + i;
+		if (pud_val(*pud))
+			return false;
+	}
+
+	/* free a pud table */
+	free_pagetable(pgd_page(*pgd));
+	pgd_clear(pgd);
+
+	return true;
+}
+
+static void __meminit
+phys_pte_remove(pte_t *pte_page, unsigned long addr, unsigned long end)
+{
+	unsigned pages = 0;
+	int i = pte_index(addr);
+
+	pte_t *pte = pte_page + pte_index(addr);
+
+	for (; i < PTRS_PER_PTE; i++, addr += PAGE_SIZE, pte++) {
+
+		if (addr >= end)
+			break;
+
+		if (!pte_present(*pte))
+			continue;
+
+		pages++;
+		set_pte(pte, __pte(0));
+	}
+
+	update_page_count(PG_LEVEL_4K, -pages);
+}
+
+static void __meminit
+phys_pmd_remove(pmd_t *pmd_page, unsigned long addr, unsigned long end)
+{
+	unsigned long pages = 0, next;
+	int i = pmd_index(addr);
+
+	for (; i < PTRS_PER_PMD && addr < end; i++, addr = next) {
+		unsigned long pte_phys;
+		pmd_t *pmd = pmd_page + pmd_index(addr);
+		pte_t *pte;
+
+		next = pmd_addr_end(addr, end);
+
+		if (!pmd_present(*pmd))
+			continue;
+
+		if (pmd_large(*pmd)) {
+			if (IS_ALIGNED(addr, PMD_SIZE) &&
+			    IS_ALIGNED(next, PMD_SIZE)) {
+				set_pmd(pmd, __pmd(0));
+				pages++;
+				continue;
+			}
+
+			/*
+			 * We use 2M page, but we need to remove part of them,
+			 * so split 2M page to 4K page.
+			 */
+			pte = alloc_low_page(&pte_phys);
+			BUG_ON(!pte);
+			__split_large_page((pte_t *)pmd,
+					   (unsigned long)__va(addr), pte);
+
+			spin_lock(&init_mm.page_table_lock);
+			pmd_populate_kernel(&init_mm, pmd, __va(pte_phys));
+			spin_unlock(&init_mm.page_table_lock);
+
+			/* Do a global flush tlb after splitting a large page */
+			flush_tlb_all();
+		}
+
+		spin_lock(&init_mm.page_table_lock);
+		pte = map_low_page((pte_t *)pmd_page_vaddr(*pmd));
+		phys_pte_remove(pte, addr, next);
+		free_pte_table(pte, pmd);
+		unmap_low_page(pte);
+		spin_unlock(&init_mm.page_table_lock);
+	}
+	update_page_count(PG_LEVEL_2M, -pages);
+}
+
+static void __meminit
+phys_pud_remove(pud_t *pud_page, unsigned long addr, unsigned long end)
+{
+	unsigned long pages = 0, next;
+	int i = pud_index(addr);
+
+	for (; i < PTRS_PER_PUD && addr < end; i++, addr = next) {
+		unsigned long pmd_phys;
+		pud_t *pud = pud_page + pud_index(addr);
+		pmd_t *pmd;
+
+		next = pud_addr_end(addr, end);
+
+		if (!pud_present(*pud))
+			continue;
+
+		if (pud_large(*pud)) {
+			if (IS_ALIGNED(addr, PUD_SIZE) &&
+			    IS_ALIGNED(next, PUD_SIZE)) {
+				set_pud(pud, __pud(0));
+				pages++;
+				continue;
+			}
+
+			/*
+			 * We use 1G page, but we need to remove part of them,
+			 * so split 1G page to 2M page.
+			 */
+			pmd = alloc_low_page(&pmd_phys);
+			BUG_ON(!pmd);
+			__split_large_page((pte_t *)pud,
+					   (unsigned long)__va(addr),
+					   (pte_t *)pmd);
+
+			spin_lock(&init_mm.page_table_lock);
+			pud_populate(&init_mm, pud, __va(pmd_phys));
+			spin_unlock(&init_mm.page_table_lock);
+
+			/* Do a global flush tlb after splitting a large page */
+			flush_tlb_all();
+		}
+
+		pmd = map_low_page((pmd_t *)pud_page_vaddr(*pud));
+		phys_pmd_remove(pmd, addr, next);
+		free_pmd_table(pmd, pud);
+		unmap_low_page(pmd);
+	}
+
+	update_page_count(PG_LEVEL_1G, -pages);
+}
+
+void __meminit
+kernel_physical_mapping_remove(unsigned long start, unsigned long end)
+{
+	unsigned long next;
+	bool pgd_changed = false;
+
+	start = (unsigned long)__va(start);
+	end = (unsigned long)__va(end);
+
+	for (; start < end; start = next) {
+		pgd_t *pgd = pgd_offset_k(start);
+		pud_t *pud;
+
+		next = pgd_addr_end(start, end);
+
+		if (!pgd_present(*pgd))
+			continue;
+
+		pud = map_low_page((pud_t *)pgd_page_vaddr(*pgd));
+		phys_pud_remove(pud, __pa(start), __pa(next));
+		if (free_pud_table(pud, pgd))
+			pgd_changed = true;
+		unmap_low_page(pud);
+	}
+
+	if (pgd_changed)
+		sync_global_pgds(start, end - 1);
+
+	flush_tlb_all();
+}
+
 #ifdef CONFIG_MEMORY_HOTREMOVE
 int __ref arch_remove_memory(u64 start, u64 size)
 {
@@ -692,6 +921,8 @@ int __ref arch_remove_memory(u64 start, u64 size)
 	ret = __remove_pages(zone, start_pfn, nr_pages);
 	WARN_ON_ONCE(ret);
 
+	kernel_physical_mapping_remove(start, start + size);
+
 	return ret;
 }
 #endif
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index a718e0d..7dcb6f9 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -501,21 +501,13 @@ out_unlock:
 	return do_split;
 }
 
-static int split_large_page(pte_t *kpte, unsigned long address)
+int __split_large_page(pte_t *kpte, unsigned long address, pte_t *pbase)
 {
 	unsigned long pfn, pfninc = 1;
 	unsigned int i, level;
-	pte_t *pbase, *tmp;
+	pte_t *tmp;
 	pgprot_t ref_prot;
-	struct page *base;
-
-	if (!debug_pagealloc)
-		spin_unlock(&cpa_lock);
-	base = alloc_pages(GFP_KERNEL | __GFP_NOTRACK, 0);
-	if (!debug_pagealloc)
-		spin_lock(&cpa_lock);
-	if (!base)
-		return -ENOMEM;
+	struct page *base = virt_to_page(pbase);
 
 	spin_lock(&pgd_lock);
 	/*
@@ -523,10 +515,11 @@ static int split_large_page(pte_t *kpte, unsigned long address)
 	 * up for us already:
 	 */
 	tmp = lookup_address(address, &level);
-	if (tmp != kpte)
-		goto out_unlock;
+	if (tmp != kpte) {
+		spin_unlock(&pgd_lock);
+		return 1;
+	}
 
-	pbase = (pte_t *)page_address(base);
 	paravirt_alloc_pte(&init_mm, page_to_pfn(base));
 	ref_prot = pte_pgprot(pte_clrhuge(*kpte));
 	/*
@@ -579,17 +572,27 @@ static int split_large_page(pte_t *kpte, unsigned long address)
 	 * going on.
 	 */
 	__flush_tlb_all();
+	spin_unlock(&pgd_lock);
 
-	base = NULL;
+	return 0;
+}
 
-out_unlock:
-	/*
-	 * If we dropped out via the lookup_address check under
-	 * pgd_lock then stick the page back into the pool:
-	 */
-	if (base)
+static int split_large_page(pte_t *kpte, unsigned long address)
+{
+	pte_t *pbase;
+	struct page *base;
+
+	if (!debug_pagealloc)
+		spin_unlock(&cpa_lock);
+	base = alloc_pages(GFP_KERNEL | __GFP_NOTRACK, 0);
+	if (!debug_pagealloc)
+		spin_lock(&cpa_lock);
+	if (!base)
+		return -ENOMEM;
+
+	pbase = (pte_t *)page_address(base);
+	if (__split_large_page(kpte, address, pbase))
 		__free_page(base);
-	spin_unlock(&pgd_lock);
 
 	return 0;
 }
-- 
1.8.0

[PATCH v3 10/12] memory-hotplug: memory_hotplug: clear zone when removing the memory

[Wen Congyang]

From: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>

When a memory is added, we update zone's and pgdat's start_pfn and
spanned_pages in the function __add_zone(). So we should revert them
when the memory is removed.

The patch adds a new function __remove_zone() to do this.

CC: David Rientjes <rientjes@google.com>
CC: Jiang Liu <liuj97@gmail.com>
CC: Len Brown <len.brown@intel.com>
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>
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
---
 mm/memory_hotplug.c | 207 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 207 insertions(+)

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 03153cf..7bcced0 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -312,10 +312,213 @@ static int __meminit __add_section(int nid, struct zone *zone,
 	return register_new_memory(nid, __pfn_to_section(phys_start_pfn));
 }
 
+/* find the smallest valid pfn in the range [start_pfn, end_pfn) */
+static int find_smallest_section_pfn(int nid, struct zone *zone,
+				     unsigned long start_pfn,
+				     unsigned long end_pfn)
+{
+	struct mem_section *ms;
+
+	for (; start_pfn < end_pfn; start_pfn += PAGES_PER_SECTION) {
+		ms = __pfn_to_section(start_pfn);
+
+		if (unlikely(!valid_section(ms)))
+			continue;
+
+		if (unlikely(pfn_to_nid(start_pfn) != nid))
+			continue;
+
+		if (zone && zone != page_zone(pfn_to_page(start_pfn)))
+			continue;
+
+		return start_pfn;
+	}
+
+	return 0;
+}
+
+/* find the biggest valid pfn in the range [start_pfn, end_pfn). */
+static int find_biggest_section_pfn(int nid, struct zone *zone,
+				    unsigned long start_pfn,
+				    unsigned long end_pfn)
+{
+	struct mem_section *ms;
+	unsigned long pfn;
+
+	/* pfn is the end pfn of a memory section. */
+	pfn = end_pfn - 1;
+	for (; pfn >= start_pfn; pfn -= PAGES_PER_SECTION) {
+		ms = __pfn_to_section(pfn);
+
+		if (unlikely(!valid_section(ms)))
+			continue;
+
+		if (unlikely(pfn_to_nid(pfn) != nid))
+			continue;
+
+		if (zone && zone != page_zone(pfn_to_page(pfn)))
+			continue;
+
+		return pfn;
+	}
+
+	return 0;
+}
+
+static void shrink_zone_span(struct zone *zone, unsigned long start_pfn,
+			     unsigned long end_pfn)
+{
+	unsigned long zone_start_pfn =  zone->zone_start_pfn;
+	unsigned long zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages;
+	unsigned long pfn;
+	struct mem_section *ms;
+	int nid = zone_to_nid(zone);
+
+	zone_span_writelock(zone);
+	if (zone_start_pfn == start_pfn) {
+		/*
+		 * If the section is smallest section in the zone, it need
+		 * shrink zone->zone_start_pfn and zone->zone_spanned_pages.
+		 * In this case, we find second smallest valid mem_section
+		 * for shrinking zone.
+		 */
+		pfn = find_smallest_section_pfn(nid, zone, end_pfn,
+						zone_end_pfn);
+		if (pfn) {
+			zone->zone_start_pfn = pfn;
+			zone->spanned_pages = zone_end_pfn - pfn;
+		}
+	} else if (zone_end_pfn == end_pfn) {
+		/*
+		 * If the section is biggest section in the zone, it need
+		 * shrink zone->spanned_pages.
+		 * In this case, we find second biggest valid mem_section for
+		 * shrinking zone.
+		 */
+		pfn = find_biggest_section_pfn(nid, zone, zone_start_pfn,
+					       start_pfn);
+		if (pfn)
+			zone->spanned_pages = pfn - zone_start_pfn + 1;
+	}
+
+	/*
+	 * The section is not biggest or smallest mem_section in the zone, it
+	 * only creates a hole in the zone. So in this case, we need not
+	 * change the zone. But perhaps, the zone has only hole data. Thus
+	 * it check the zone has only hole or not.
+	 */
+	pfn = zone_start_pfn;
+	for (; pfn < zone_end_pfn; pfn += PAGES_PER_SECTION) {
+		ms = __pfn_to_section(pfn);
+
+		if (unlikely(!valid_section(ms)))
+			continue;
+
+		if (page_zone(pfn_to_page(pfn)) != zone)
+			continue;
+
+		 /* If the section is current section, it continues the loop */
+		if (start_pfn == pfn)
+			continue;
+
+		/* If we find valid section, we have nothing to do */
+		zone_span_writeunlock(zone);
+		return;
+	}
+
+	/* The zone has no valid section */
+	zone->zone_start_pfn = 0;
+	zone->spanned_pages = 0;
+	zone_span_writeunlock(zone);
+}
+
+static void shrink_pgdat_span(struct pglist_data *pgdat,
+			      unsigned long start_pfn, unsigned long end_pfn)
+{
+	unsigned long pgdat_start_pfn =  pgdat->node_start_pfn;
+	unsigned long pgdat_end_pfn =
+		pgdat->node_start_pfn + pgdat->node_spanned_pages;
+	unsigned long pfn;
+	struct mem_section *ms;
+	int nid = pgdat->node_id;
+
+	if (pgdat_start_pfn == start_pfn) {
+		/*
+		 * If the section is smallest section in the pgdat, it need
+		 * shrink pgdat->node_start_pfn and pgdat->node_spanned_pages.
+		 * In this case, we find second smallest valid mem_section
+		 * for shrinking zone.
+		 */
+		pfn = find_smallest_section_pfn(nid, NULL, end_pfn,
+						pgdat_end_pfn);
+		if (pfn) {
+			pgdat->node_start_pfn = pfn;
+			pgdat->node_spanned_pages = pgdat_end_pfn - pfn;
+		}
+	} else if (pgdat_end_pfn == end_pfn) {
+		/*
+		 * If the section is biggest section in the pgdat, it need
+		 * shrink pgdat->node_spanned_pages.
+		 * In this case, we find second biggest valid mem_section for
+		 * shrinking zone.
+		 */
+		pfn = find_biggest_section_pfn(nid, NULL, pgdat_start_pfn,
+					       start_pfn);
+		if (pfn)
+			pgdat->node_spanned_pages = pfn - pgdat_start_pfn + 1;
+	}
+
+	/*
+	 * If the section is not biggest or smallest mem_section in the pgdat,
+	 * it only creates a hole in the pgdat. So in this case, we need not
+	 * change the pgdat.
+	 * But perhaps, the pgdat has only hole data. Thus it check the pgdat
+	 * has only hole or not.
+	 */
+	pfn = pgdat_start_pfn;
+	for (; pfn < pgdat_end_pfn; pfn += PAGES_PER_SECTION) {
+		ms = __pfn_to_section(pfn);
+
+		if (unlikely(!valid_section(ms)))
+			continue;
+
+		if (pfn_to_nid(pfn) != nid)
+			continue;
+
+		 /* If the section is current section, it continues the loop */
+		if (start_pfn == pfn)
+			continue;
+
+		/* If we find valid section, we have nothing to do */
+		return;
+	}
+
+	/* The pgdat has no valid section */
+	pgdat->node_start_pfn = 0;
+	pgdat->node_spanned_pages = 0;
+}
+
+static void __remove_zone(struct zone *zone, unsigned long start_pfn)
+{
+	struct pglist_data *pgdat = zone->zone_pgdat;
+	int nr_pages = PAGES_PER_SECTION;
+	int zone_type;
+	unsigned long flags;
+
+	zone_type = zone - pgdat->node_zones;
+
+	pgdat_resize_lock(zone->zone_pgdat, &flags);
+	shrink_zone_span(zone, start_pfn, start_pfn + nr_pages);
+	shrink_pgdat_span(pgdat, start_pfn, start_pfn + nr_pages);
+	pgdat_resize_unlock(zone->zone_pgdat, &flags);
+}
+
 static int __remove_section(struct zone *zone, struct mem_section *ms)
 {
 	unsigned long flags;
 	struct pglist_data *pgdat = zone->zone_pgdat;
+	unsigned long start_pfn;
+	int scn_nr;
 	int ret = -EINVAL;
 
 	if (!valid_section(ms))
@@ -325,6 +528,10 @@ static int __remove_section(struct zone *zone, struct mem_section *ms)
 	if (ret)
 		return ret;
 
+	scn_nr = __section_nr(ms);
+	start_pfn = section_nr_to_pfn(scn_nr);
+	__remove_zone(zone, start_pfn);
+
 	pgdat_resize_lock(pgdat, &flags);
 	sparse_remove_one_section(zone, ms);
 	pgdat_resize_unlock(pgdat, &flags);
-- 
1.8.0

[PATCH v3 11/12] memory-hotplug: remove sysfs file of node

[Wen Congyang]

This patch introduces a new function try_offline_node() to
remove sysfs file of node when all memory sections of this
node are removed. If some memory sections of this node are
not removed, this function does nothing.

CC: David Rientjes <rientjes@google.com>
CC: Jiang Liu <liuj97@gmail.com>
CC: Len Brown <len.brown@intel.com>
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>
CC: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
---
 drivers/acpi/acpi_memhotplug.c |  8 +++++-
 include/linux/memory_hotplug.h |  2 +-
 mm/memory_hotplug.c            | 58 ++++++++++++++++++++++++++++++++++++++++--
 3 files changed, 64 insertions(+), 4 deletions(-)

diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
index 24c807f..0780f99 100644
--- a/drivers/acpi/acpi_memhotplug.c
+++ b/drivers/acpi/acpi_memhotplug.c
@@ -310,7 +310,9 @@ static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
 {
 	int result;
 	struct acpi_memory_info *info, *n;
+	int node;
 
+	node = acpi_get_node(mem_device->device->handle);
 
 	/*
 	 * Ask the VM to offline this memory range.
@@ -318,7 +320,11 @@ static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
 	 */
 	list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
 		if (info->enabled) {
-			result = remove_memory(info->start_addr, info->length);
+			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;
 		}
diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index d4c4402..7b4cfe6 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -231,7 +231,7 @@ extern int arch_add_memory(int nid, u64 start, u64 size);
 extern int offline_pages(unsigned long start_pfn, unsigned long nr_pages);
 extern int offline_memory_block(struct memory_block *mem);
 extern bool is_memblock_offlined(struct memory_block *mem);
-extern int remove_memory(u64 start, u64 size);
+extern int remove_memory(int node, u64 start, u64 size);
 extern int sparse_add_one_section(struct zone *zone, unsigned long start_pfn,
 								int nr_pages);
 extern void sparse_remove_one_section(struct zone *zone, struct mem_section *ms);
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 7bcced0..d965da3 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -29,6 +29,7 @@
 #include <linux/suspend.h>
 #include <linux/mm_inline.h>
 #include <linux/firmware-map.h>
+#include <linux/stop_machine.h>
 
 #include <asm/tlbflush.h>
 
@@ -1299,7 +1300,58 @@ static int is_memblock_offlined_cb(struct memory_block *mem, void *arg)
 	return ret;
 }
 
-int __ref remove_memory(u64 start, u64 size)
+static int check_cpu_on_node(void *data)
+{
+	struct pglist_data *pgdat = data;
+	int cpu;
+
+	for_each_present_cpu(cpu) {
+		if (cpu_to_node(cpu) == pgdat->node_id)
+			/*
+			 * the cpu on this node isn't removed, and we can't
+			 * offline this node.
+			 */
+			return -EBUSY;
+	}
+
+	return 0;
+}
+
+/* offline the node if all memory sections of this node are removed */
+static void try_offline_node(int nid)
+{
+	unsigned long start_pfn = NODE_DATA(nid)->node_start_pfn;
+	unsigned long end_pfn = start_pfn + NODE_DATA(nid)->node_spanned_pages;
+	unsigned long pfn;
+
+	for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
+		unsigned long section_nr = pfn_to_section_nr(pfn);
+
+		if (!present_section_nr(section_nr))
+			continue;
+
+		if (pfn_to_nid(pfn) != nid)
+			continue;
+
+		/*
+		 * some memory sections of this node are not removed, and we
+		 * can't offline node now.
+		 */
+		return;
+	}
+
+	if (stop_machine(check_cpu_on_node, NODE_DATA(nid), NULL))
+		return;
+
+	/*
+	 * all memory/cpu of this node are removed, we can offline this
+	 * node now.
+	 */
+	node_set_offline(nid);
+	unregister_one_node(nid);
+}
+
+int __ref remove_memory(int nid, u64 start, u64 size)
 {
 	unsigned long start_pfn, end_pfn;
 	int ret = 0;
@@ -1346,6 +1398,8 @@ repeat:
 
 	arch_remove_memory(start, size);
 
+	try_offline_node(nid);
+
 	unlock_memory_hotplug();
 
 	return 0;
@@ -1355,7 +1409,7 @@ int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
 {
 	return -EINVAL;
 }
-int remove_memory(u64 start, u64 size)
+int remove_memory(int nid, u64 start, u64 size)
 {
 	return -EINVAL;
 }
-- 
1.8.0

Re: [PATCH v3 11/12] memory-hotplug: remove sysfs file of node

[Yasuaki Ishimatsu]

Hi Wen,

This patch cannot be applied, if I apply latest acpi framework's patch-set:

https://lkml.org/lkml/2012/11/15/21

Because acpi_memory_disable_device() is gone by the patch-set.

I updated the patch and attached it on the mail.

2012/11/01 18:44, Wen Congyang wrote:
> This patch introduces a new function try_offline_node() to
> remove sysfs file of node when all memory sections of this
> node are removed. If some memory sections of this node are
> not removed, this function does nothing.
> 
> CC: David Rientjes <rientjes@google.com>
> CC: Jiang Liu <liuj97@gmail.com>
> CC: Len Brown <len.brown@intel.com>
> 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>
> CC: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
> Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
> ---
>   drivers/acpi/acpi_memhotplug.c |  8 +++++-
>   include/linux/memory_hotplug.h |  2 +-
>   mm/memory_hotplug.c            | 58 ++++++++++++++++++++++++++++++++++++++++--
>   3 files changed, 64 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
> index 24c807f..0780f99 100644
> --- a/drivers/acpi/acpi_memhotplug.c
> +++ b/drivers/acpi/acpi_memhotplug.c
> @@ -310,7 +310,9 @@ static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
>   {
>   	int result;
>   	struct acpi_memory_info *info, *n;
> +	int node;
>   
> +	node = acpi_get_node(mem_device->device->handle);
>   
>   	/*
>   	 * Ask the VM to offline this memory range.
> @@ -318,7 +320,11 @@ static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
>   	 */
>   	list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
>   		if (info->enabled) {
> -			result = remove_memory(info->start_addr, info->length);
> +			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;
>   		}
> diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
> index d4c4402..7b4cfe6 100644
> --- a/include/linux/memory_hotplug.h
> +++ b/include/linux/memory_hotplug.h
> @@ -231,7 +231,7 @@ extern int arch_add_memory(int nid, u64 start, u64 size);
>   extern int offline_pages(unsigned long start_pfn, unsigned long nr_pages);
>   extern int offline_memory_block(struct memory_block *mem);
>   extern bool is_memblock_offlined(struct memory_block *mem);
> -extern int remove_memory(u64 start, u64 size);
> +extern int remove_memory(int node, u64 start, u64 size);
>   extern int sparse_add_one_section(struct zone *zone, unsigned long start_pfn,
>   								int nr_pages);
>   extern void sparse_remove_one_section(struct zone *zone, struct mem_section *ms);
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index 7bcced0..d965da3 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -29,6 +29,7 @@
>   #include <linux/suspend.h>
>   #include <linux/mm_inline.h>
>   #include <linux/firmware-map.h>
> +#include <linux/stop_machine.h>
>   
>   #include <asm/tlbflush.h>
>   
> @@ -1299,7 +1300,58 @@ static int is_memblock_offlined_cb(struct memory_block *mem, void *arg)
>   	return ret;
>   }
>   
> -int __ref remove_memory(u64 start, u64 size)
> +static int check_cpu_on_node(void *data)
> +{
> +	struct pglist_data *pgdat = data;
> +	int cpu;
> +
> +	for_each_present_cpu(cpu) {
> +		if (cpu_to_node(cpu) == pgdat->node_id)
> +			/*
> +			 * the cpu on this node isn't removed, and we can't
> +			 * offline this node.
> +			 */
> +			return -EBUSY;
> +	}
> +
> +	return 0;
> +}
> +
> +/* offline the node if all memory sections of this node are removed */
> +static void try_offline_node(int nid)
> +{
> +	unsigned long start_pfn = NODE_DATA(nid)->node_start_pfn;
> +	unsigned long end_pfn = start_pfn + NODE_DATA(nid)->node_spanned_pages;
> +	unsigned long pfn;
> +
> +	for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
> +		unsigned long section_nr = pfn_to_section_nr(pfn);
> +
> +		if (!present_section_nr(section_nr))
> +			continue;
> +
> +		if (pfn_to_nid(pfn) != nid)
> +			continue;
> +
> +		/*
> +		 * some memory sections of this node are not removed, and we
> +		 * can't offline node now.
> +		 */
> +		return;
> +	}
> +
> +	if (stop_machine(check_cpu_on_node, NODE_DATA(nid), NULL))
> +		return;
> +
> +	/*
> +	 * all memory/cpu of this node are removed, we can offline this
> +	 * node now.
> +	 */
> +	node_set_offline(nid);
> +	unregister_one_node(nid);
> +}
> +
> +int __ref remove_memory(int nid, u64 start, u64 size)
>   {
>   	unsigned long start_pfn, end_pfn;
>   	int ret = 0;
> @@ -1346,6 +1398,8 @@ repeat:
>   
>   	arch_remove_memory(start, size);
>   
> +	try_offline_node(nid);
> +
>   	unlock_memory_hotplug();
>   
>   	return 0;
> @@ -1355,7 +1409,7 @@ int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
>   {
>   	return -EINVAL;
>   }
> -int remove_memory(u64 start, u64 size)
> +int remove_memory(int nid, u64 start, u64 size)
>   {
>   	return -EINVAL;
>   }
> 

---
This patch introduces a new function try_offline_node() to
remove sysfs file of node when all memory sections of this
node are removed. If some memory sections of this node are
not removed, this function does nothing.

CC: David Rientjes <rientjes@google.com>
CC: Jiang Liu <liuj97@gmail.com>
CC: Len Brown <len.brown@intel.com>
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>
CC: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
---
 drivers/acpi/acpi_memhotplug.c |    9 +++++-
 include/linux/memory_hotplug.h |    2 -
 mm/memory_hotplug.c            |   58 +++++++++++++++++++++++++++++++++++++++--
 3 files changed, 65 insertions(+), 4 deletions(-)

Index: linux-3.7-rc6/drivers/acpi/acpi_memhotplug.c
===================================================================
--- linux-3.7-rc6.orig/drivers/acpi/acpi_memhotplug.c	2012-11-19 16:16:55.161912688 +0900
+++ linux-3.7-rc6/drivers/acpi/acpi_memhotplug.c	2012-11-19 16:17:05.346912109 +0900
@@ -295,6 +295,9 @@ static int acpi_memory_remove_memory(str
 {
 	int result = 0;
 	struct acpi_memory_info *info, *n;
+	int node;
+
+	node = acpi_get_node(mem_device->device->handle);
 
 	list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
 		if (info->failed)
@@ -308,7 +311,11 @@ static int acpi_memory_remove_memory(str
 			 */
 			return -EBUSY;
 
-		result = remove_memory(info->start_addr, info->length);
+		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;
 
Index: linux-3.7-rc6/include/linux/memory_hotplug.h
===================================================================
--- linux-3.7-rc6.orig/include/linux/memory_hotplug.h	2012-11-19 16:16:55.167912687 +0900
+++ linux-3.7-rc6/include/linux/memory_hotplug.h	2012-11-19 16:17:05.348912109 +0900
@@ -242,7 +242,7 @@ extern int arch_add_memory(int nid, u64 
 extern int offline_pages(unsigned long start_pfn, unsigned long nr_pages);
 extern int offline_memory_block(struct memory_block *mem);
 extern bool is_memblock_offlined(struct memory_block *mem);
-extern int remove_memory(u64 start, u64 size);
+extern int remove_memory(int node, u64 start, u64 size);
 extern int sparse_add_one_section(struct zone *zone, unsigned long start_pfn,
 								int nr_pages);
 extern void sparse_remove_one_section(struct zone *zone, struct mem_section *ms);
Index: linux-3.7-rc6/mm/memory_hotplug.c
===================================================================
--- linux-3.7-rc6.orig/mm/memory_hotplug.c	2012-11-19 16:16:55.164912687 +0900
+++ linux-3.7-rc6/mm/memory_hotplug.c	2012-11-19 16:17:05.356912108 +0900
@@ -29,6 +29,7 @@
 #include <linux/suspend.h>
 #include <linux/mm_inline.h>
 #include <linux/firmware-map.h>
+#include <linux/stop_machine.h>
 
 #include <asm/tlbflush.h>
 
@@ -1652,7 +1653,58 @@ static int is_memblock_offlined_cb(struc
 	return ret;
 }
 
-int __ref remove_memory(u64 start, u64 size)
+static int check_cpu_on_node(void *data)
+{
+	struct pglist_data *pgdat = data;
+	int cpu;
+
+	for_each_present_cpu(cpu) {
+		if (cpu_to_node(cpu) == pgdat->node_id)
+			/*
+			 * the cpu on this node isn't removed, and we can't
+			 * offline this node.
+			 */
+			return -EBUSY;
+	}
+
+	return 0;
+}
+
+/* offline the node if all memory sections of this node are removed */
+static void try_offline_node(int nid)
+{
+	unsigned long start_pfn = NODE_DATA(nid)->node_start_pfn;
+	unsigned long end_pfn = start_pfn + NODE_DATA(nid)->node_spanned_pages;
+	unsigned long pfn;
+
+	for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
+		unsigned long section_nr = pfn_to_section_nr(pfn);
+
+		if (!present_section_nr(section_nr))
+			continue;
+
+		if (pfn_to_nid(pfn) != nid)
+			continue;
+
+		/*
+		 * some memory sections of this node are not removed, and we
+		 * can't offline node now.
+		 */
+		return;
+	}
+
+	if (stop_machine(check_cpu_on_node, NODE_DATA(nid), NULL))
+		return;
+
+	/*
+	 * all memory/cpu of this node are removed, we can offline this
+	 * node now.
+	 */
+	node_set_offline(nid);
+	unregister_one_node(nid);
+}
+
+int __ref remove_memory(int nid, u64 start, u64 size)
 {
 	unsigned long start_pfn, end_pfn;
 	int ret = 0;
@@ -1699,6 +1751,8 @@ repeat:
 
 	arch_remove_memory(start, size);
 
+	try_offline_node(nid);
+
 	unlock_memory_hotplug();
 
 	return 0;
@@ -1708,7 +1762,7 @@ int offline_pages(unsigned long start_pf
 {
 	return -EINVAL;
 }
-int remove_memory(u64 start, u64 size)
+int remove_memory(int nid, u64 start, u64 size)
 {
 	return -EINVAL;
 }

Re: [PATCH v3 11/12] memory-hotplug: remove sysfs file of node

[Wen Congyang]

At 11/19/2012 06:08 PM, Yasuaki Ishimatsu Wrote:
> Hi Wen,
> 
> This patch cannot be applied, if I apply latest acpi framework's patch-set:
> 
> https://lkml.org/lkml/2012/11/15/21
> 
> Because acpi_memory_disable_device() is gone by the patch-set.

The patchset is not for pm tree, so I don't apply the patchset in pm tree
before generating this patchset.

Thanks
Wen Congyang

> 
> I updated the patch and attached it on the mail.
> 
> 2012/11/01 18:44, Wen Congyang wrote:
>> This patch introduces a new function try_offline_node() to
>> remove sysfs file of node when all memory sections of this
>> node are removed. If some memory sections of this node are
>> not removed, this function does nothing.
>>
>> CC: David Rientjes <rientjes@google.com>
>> CC: Jiang Liu <liuj97@gmail.com>
>> CC: Len Brown <len.brown@intel.com>
>> 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>
>> CC: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
>> Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
>> ---
>>   drivers/acpi/acpi_memhotplug.c |  8 +++++-
>>   include/linux/memory_hotplug.h |  2 +-
>>   mm/memory_hotplug.c            | 58 ++++++++++++++++++++++++++++++++++++++++--
>>   3 files changed, 64 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
>> index 24c807f..0780f99 100644
>> --- a/drivers/acpi/acpi_memhotplug.c
>> +++ b/drivers/acpi/acpi_memhotplug.c
>> @@ -310,7 +310,9 @@ static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
>>   {
>>   	int result;
>>   	struct acpi_memory_info *info, *n;
>> +	int node;
>>   
>> +	node = acpi_get_node(mem_device->device->handle);
>>   
>>   	/*
>>   	 * Ask the VM to offline this memory range.
>> @@ -318,7 +320,11 @@ static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
>>   	 */
>>   	list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
>>   		if (info->enabled) {
>> -			result = remove_memory(info->start_addr, info->length);
>> +			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;
>>   		}
>> diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
>> index d4c4402..7b4cfe6 100644
>> --- a/include/linux/memory_hotplug.h
>> +++ b/include/linux/memory_hotplug.h
>> @@ -231,7 +231,7 @@ extern int arch_add_memory(int nid, u64 start, u64 size);
>>   extern int offline_pages(unsigned long start_pfn, unsigned long nr_pages);
>>   extern int offline_memory_block(struct memory_block *mem);
>>   extern bool is_memblock_offlined(struct memory_block *mem);
>> -extern int remove_memory(u64 start, u64 size);
>> +extern int remove_memory(int node, u64 start, u64 size);
>>   extern int sparse_add_one_section(struct zone *zone, unsigned long start_pfn,
>>   								int nr_pages);
>>   extern void sparse_remove_one_section(struct zone *zone, struct mem_section *ms);
>> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
>> index 7bcced0..d965da3 100644
>> --- a/mm/memory_hotplug.c
>> +++ b/mm/memory_hotplug.c
>> @@ -29,6 +29,7 @@
>>   #include <linux/suspend.h>
>>   #include <linux/mm_inline.h>
>>   #include <linux/firmware-map.h>
>> +#include <linux/stop_machine.h>
>>   
>>   #include <asm/tlbflush.h>
>>   
>> @@ -1299,7 +1300,58 @@ static int is_memblock_offlined_cb(struct memory_block *mem, void *arg)
>>   	return ret;
>>   }
>>   
>> -int __ref remove_memory(u64 start, u64 size)
>> +static int check_cpu_on_node(void *data)
>> +{
>> +	struct pglist_data *pgdat = data;
>> +	int cpu;
>> +
>> +	for_each_present_cpu(cpu) {
>> +		if (cpu_to_node(cpu) == pgdat->node_id)
>> +			/*
>> +			 * the cpu on this node isn't removed, and we can't
>> +			 * offline this node.
>> +			 */
>> +			return -EBUSY;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +/* offline the node if all memory sections of this node are removed */
>> +static void try_offline_node(int nid)
>> +{
>> +	unsigned long start_pfn = NODE_DATA(nid)->node_start_pfn;
>> +	unsigned long end_pfn = start_pfn + NODE_DATA(nid)->node_spanned_pages;
>> +	unsigned long pfn;
>> +
>> +	for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
>> +		unsigned long section_nr = pfn_to_section_nr(pfn);
>> +
>> +		if (!present_section_nr(section_nr))
>> +			continue;
>> +
>> +		if (pfn_to_nid(pfn) != nid)
>> +			continue;
>> +
>> +		/*
>> +		 * some memory sections of this node are not removed, and we
>> +		 * can't offline node now.
>> +		 */
>> +		return;
>> +	}
>> +
>> +	if (stop_machine(check_cpu_on_node, NODE_DATA(nid), NULL))
>> +		return;
>> +
>> +	/*
>> +	 * all memory/cpu of this node are removed, we can offline this
>> +	 * node now.
>> +	 */
>> +	node_set_offline(nid);
>> +	unregister_one_node(nid);
>> +}
>> +
>> +int __ref remove_memory(int nid, u64 start, u64 size)
>>   {
>>   	unsigned long start_pfn, end_pfn;
>>   	int ret = 0;
>> @@ -1346,6 +1398,8 @@ repeat:
>>   
>>   	arch_remove_memory(start, size);
>>   
>> +	try_offline_node(nid);
>> +
>>   	unlock_memory_hotplug();
>>   
>>   	return 0;
>> @@ -1355,7 +1409,7 @@ int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
>>   {
>>   	return -EINVAL;
>>   }
>> -int remove_memory(u64 start, u64 size)
>> +int remove_memory(int nid, u64 start, u64 size)
>>   {
>>   	return -EINVAL;
>>   }
>>
> 
> ---
> This patch introduces a new function try_offline_node() to
> remove sysfs file of node when all memory sections of this
> node are removed. If some memory sections of this node are
> not removed, this function does nothing.
> 
> CC: David Rientjes <rientjes@google.com>
> CC: Jiang Liu <liuj97@gmail.com>
> CC: Len Brown <len.brown@intel.com>
> 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>
> CC: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
> Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
> ---
>  drivers/acpi/acpi_memhotplug.c |    9 +++++-
>  include/linux/memory_hotplug.h |    2 -
>  mm/memory_hotplug.c            |   58 +++++++++++++++++++++++++++++++++++++++--
>  3 files changed, 65 insertions(+), 4 deletions(-)
> 
> Index: linux-3.7-rc6/drivers/acpi/acpi_memhotplug.c
> ===================================================================
> --- linux-3.7-rc6.orig/drivers/acpi/acpi_memhotplug.c	2012-11-19 16:16:55.161912688 +0900
> +++ linux-3.7-rc6/drivers/acpi/acpi_memhotplug.c	2012-11-19 16:17:05.346912109 +0900
> @@ -295,6 +295,9 @@ static int acpi_memory_remove_memory(str
>  {
>  	int result = 0;
>  	struct acpi_memory_info *info, *n;
> +	int node;
> +
> +	node = acpi_get_node(mem_device->device->handle);
>  
>  	list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
>  		if (info->failed)
> @@ -308,7 +311,11 @@ static int acpi_memory_remove_memory(str
>  			 */
>  			return -EBUSY;
>  
> -		result = remove_memory(info->start_addr, info->length);
> +		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;
>  
> Index: linux-3.7-rc6/include/linux/memory_hotplug.h
> ===================================================================
> --- linux-3.7-rc6.orig/include/linux/memory_hotplug.h	2012-11-19 16:16:55.167912687 +0900
> +++ linux-3.7-rc6/include/linux/memory_hotplug.h	2012-11-19 16:17:05.348912109 +0900
> @@ -242,7 +242,7 @@ extern int arch_add_memory(int nid, u64 
>  extern int offline_pages(unsigned long start_pfn, unsigned long nr_pages);
>  extern int offline_memory_block(struct memory_block *mem);
>  extern bool is_memblock_offlined(struct memory_block *mem);
> -extern int remove_memory(u64 start, u64 size);
> +extern int remove_memory(int node, u64 start, u64 size);
>  extern int sparse_add_one_section(struct zone *zone, unsigned long start_pfn,
>  								int nr_pages);
>  extern void sparse_remove_one_section(struct zone *zone, struct mem_section *ms);
> Index: linux-3.7-rc6/mm/memory_hotplug.c
> ===================================================================
> --- linux-3.7-rc6.orig/mm/memory_hotplug.c	2012-11-19 16:16:55.164912687 +0900
> +++ linux-3.7-rc6/mm/memory_hotplug.c	2012-11-19 16:17:05.356912108 +0900
> @@ -29,6 +29,7 @@
>  #include <linux/suspend.h>
>  #include <linux/mm_inline.h>
>  #include <linux/firmware-map.h>
> +#include <linux/stop_machine.h>
>  
>  #include <asm/tlbflush.h>
>  
> @@ -1652,7 +1653,58 @@ static int is_memblock_offlined_cb(struc
>  	return ret;
>  }
>  
> -int __ref remove_memory(u64 start, u64 size)
> +static int check_cpu_on_node(void *data)
> +{
> +	struct pglist_data *pgdat = data;
> +	int cpu;
> +
> +	for_each_present_cpu(cpu) {
> +		if (cpu_to_node(cpu) == pgdat->node_id)
> +			/*
> +			 * the cpu on this node isn't removed, and we can't
> +			 * offline this node.
> +			 */
> +			return -EBUSY;
> +	}
> +
> +	return 0;
> +}
> +
> +/* offline the node if all memory sections of this node are removed */
> +static void try_offline_node(int nid)
> +{
> +	unsigned long start_pfn = NODE_DATA(nid)->node_start_pfn;
> +	unsigned long end_pfn = start_pfn + NODE_DATA(nid)->node_spanned_pages;
> +	unsigned long pfn;
> +
> +	for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
> +		unsigned long section_nr = pfn_to_section_nr(pfn);
> +
> +		if (!present_section_nr(section_nr))
> +			continue;
> +
> +		if (pfn_to_nid(pfn) != nid)
> +			continue;
> +
> +		/*
> +		 * some memory sections of this node are not removed, and we
> +		 * can't offline node now.
> +		 */
> +		return;
> +	}
> +
> +	if (stop_machine(check_cpu_on_node, NODE_DATA(nid), NULL))
> +		return;
> +
> +	/*
> +	 * all memory/cpu of this node are removed, we can offline this
> +	 * node now.
> +	 */
> +	node_set_offline(nid);
> +	unregister_one_node(nid);
> +}
> +
> +int __ref remove_memory(int nid, u64 start, u64 size)
>  {
>  	unsigned long start_pfn, end_pfn;
>  	int ret = 0;
> @@ -1699,6 +1751,8 @@ repeat:
>  
>  	arch_remove_memory(start, size);
>  
> +	try_offline_node(nid);
> +
>  	unlock_memory_hotplug();
>  
>  	return 0;
> @@ -1708,7 +1762,7 @@ int offline_pages(unsigned long start_pf
>  {
>  	return -EINVAL;
>  }
> -int remove_memory(u64 start, u64 size)
> +int remove_memory(int nid, u64 start, u64 size)
>  {
>  	return -EINVAL;
>  }
> 
> 

Re: [PATCH v3 11/12] memory-hotplug: remove sysfs file of node

[Jianguo Wu]

On 2012/11/1 17:44, Wen Congyang wrote:
> This patch introduces a new function try_offline_node() to
> remove sysfs file of node when all memory sections of this
> node are removed. If some memory sections of this node are
> not removed, this function does nothing.
> 
> CC: David Rientjes <rientjes@google.com>
> CC: Jiang Liu <liuj97@gmail.com>
> CC: Len Brown <len.brown@intel.com>
> 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>
> CC: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
> Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
> ---
>  drivers/acpi/acpi_memhotplug.c |  8 +++++-
>  include/linux/memory_hotplug.h |  2 +-
>  mm/memory_hotplug.c            | 58 ++++++++++++++++++++++++++++++++++++++++--
>  3 files changed, 64 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
> index 24c807f..0780f99 100644
> --- a/drivers/acpi/acpi_memhotplug.c
> +++ b/drivers/acpi/acpi_memhotplug.c
> @@ -310,7 +310,9 @@ static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
>  {
>  	int result;
>  	struct acpi_memory_info *info, *n;
> +	int node;
>  
> +	node = acpi_get_node(mem_device->device->handle);
>  
>  	/*
>  	 * Ask the VM to offline this memory range.
> @@ -318,7 +320,11 @@ static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
>  	 */
>  	list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
>  		if (info->enabled) {
> -			result = remove_memory(info->start_addr, info->length);
> +			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;
>  		}
> diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
> index d4c4402..7b4cfe6 100644
> --- a/include/linux/memory_hotplug.h
> +++ b/include/linux/memory_hotplug.h
> @@ -231,7 +231,7 @@ extern int arch_add_memory(int nid, u64 start, u64 size);
>  extern int offline_pages(unsigned long start_pfn, unsigned long nr_pages);
>  extern int offline_memory_block(struct memory_block *mem);
>  extern bool is_memblock_offlined(struct memory_block *mem);
> -extern int remove_memory(u64 start, u64 size);
> +extern int remove_memory(int node, u64 start, u64 size);
>  extern int sparse_add_one_section(struct zone *zone, unsigned long start_pfn,
>  								int nr_pages);
>  extern void sparse_remove_one_section(struct zone *zone, struct mem_section *ms);
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index 7bcced0..d965da3 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -29,6 +29,7 @@
>  #include <linux/suspend.h>
>  #include <linux/mm_inline.h>
>  #include <linux/firmware-map.h>
> +#include <linux/stop_machine.h>
>  
>  #include <asm/tlbflush.h>
>  
> @@ -1299,7 +1300,58 @@ static int is_memblock_offlined_cb(struct memory_block *mem, void *arg)
>  	return ret;
>  }
>  
> -int __ref remove_memory(u64 start, u64 size)
> +static int check_cpu_on_node(void *data)
> +{
> +	struct pglist_data *pgdat = data;
> +	int cpu;
> +
> +	for_each_present_cpu(cpu) {
> +		if (cpu_to_node(cpu) == pgdat->node_id)
> +			/*
> +			 * the cpu on this node isn't removed, and we can't
> +			 * offline this node.
> +			 */
> +			return -EBUSY;
> +	}
> +
> +	return 0;
> +}
> +
> +/* offline the node if all memory sections of this node are removed */
> +static void try_offline_node(int nid)
> +{
> +	unsigned long start_pfn = NODE_DATA(nid)->node_start_pfn;
> +	unsigned long end_pfn = start_pfn + NODE_DATA(nid)->node_spanned_pages;
> +	unsigned long pfn;
> +
> +	for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
> +		unsigned long section_nr = pfn_to_section_nr(pfn);
> +
> +		if (!present_section_nr(section_nr))
> +			continue;
> +
> +		if (pfn_to_nid(pfn) != nid)
> +			continue;
> +
> +		/*
> +		 * some memory sections of this node are not removed, and we
> +		 * can't offline node now.
> +		 */
> +		return;
> +	}
> +
> +	if (stop_machine(check_cpu_on_node, NODE_DATA(nid), NULL))
> +		return;

how about:
	if (nr_cpus_node(nid))
		return;
> +
> +	/*
> +	 * all memory/cpu of this node are removed, we can offline this
> +	 * node now.
> +	 */
> +	node_set_offline(nid);
> +	unregister_one_node(nid);
> +}
> +
> +int __ref remove_memory(int nid, u64 start, u64 size)
>  {
>  	unsigned long start_pfn, end_pfn;
>  	int ret = 0;
> @@ -1346,6 +1398,8 @@ repeat:
>  
>  	arch_remove_memory(start, size);
>  
> +	try_offline_node(nid);
> +
>  	unlock_memory_hotplug();
>  
>  	return 0;
> @@ -1355,7 +1409,7 @@ int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
>  {
>  	return -EINVAL;
>  }
> -int remove_memory(u64 start, u64 size)
> +int remove_memory(int nid, u64 start, u64 size)
>  {
>  	return -EINVAL;
>  }
> 

Re: [PATCH v3 11/12] memory-hotplug: remove sysfs file of node

[Wen Congyang]

At 11/26/2012 10:27 PM, Jianguo Wu Wrote:
> On 2012/11/1 17:44, Wen Congyang wrote:
>> This patch introduces a new function try_offline_node() to
>> remove sysfs file of node when all memory sections of this
>> node are removed. If some memory sections of this node are
>> not removed, this function does nothing.
>>
>> CC: David Rientjes <rientjes@google.com>
>> CC: Jiang Liu <liuj97@gmail.com>
>> CC: Len Brown <len.brown@intel.com>
>> 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>
>> CC: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
>> Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
>> ---
>>  drivers/acpi/acpi_memhotplug.c |  8 +++++-
>>  include/linux/memory_hotplug.h |  2 +-
>>  mm/memory_hotplug.c            | 58 ++++++++++++++++++++++++++++++++++++++++--
>>  3 files changed, 64 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
>> index 24c807f..0780f99 100644
>> --- a/drivers/acpi/acpi_memhotplug.c
>> +++ b/drivers/acpi/acpi_memhotplug.c
>> @@ -310,7 +310,9 @@ static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
>>  {
>>  	int result;
>>  	struct acpi_memory_info *info, *n;
>> +	int node;
>>  
>> +	node = acpi_get_node(mem_device->device->handle);
>>  
>>  	/*
>>  	 * Ask the VM to offline this memory range.
>> @@ -318,7 +320,11 @@ static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
>>  	 */
>>  	list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
>>  		if (info->enabled) {
>> -			result = remove_memory(info->start_addr, info->length);
>> +			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;
>>  		}
>> diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
>> index d4c4402..7b4cfe6 100644
>> --- a/include/linux/memory_hotplug.h
>> +++ b/include/linux/memory_hotplug.h
>> @@ -231,7 +231,7 @@ extern int arch_add_memory(int nid, u64 start, u64 size);
>>  extern int offline_pages(unsigned long start_pfn, unsigned long nr_pages);
>>  extern int offline_memory_block(struct memory_block *mem);
>>  extern bool is_memblock_offlined(struct memory_block *mem);
>> -extern int remove_memory(u64 start, u64 size);
>> +extern int remove_memory(int node, u64 start, u64 size);
>>  extern int sparse_add_one_section(struct zone *zone, unsigned long start_pfn,
>>  								int nr_pages);
>>  extern void sparse_remove_one_section(struct zone *zone, struct mem_section *ms);
>> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
>> index 7bcced0..d965da3 100644
>> --- a/mm/memory_hotplug.c
>> +++ b/mm/memory_hotplug.c
>> @@ -29,6 +29,7 @@
>>  #include <linux/suspend.h>
>>  #include <linux/mm_inline.h>
>>  #include <linux/firmware-map.h>
>> +#include <linux/stop_machine.h>
>>  
>>  #include <asm/tlbflush.h>
>>  
>> @@ -1299,7 +1300,58 @@ static int is_memblock_offlined_cb(struct memory_block *mem, void *arg)
>>  	return ret;
>>  }
>>  
>> -int __ref remove_memory(u64 start, u64 size)
>> +static int check_cpu_on_node(void *data)
>> +{
>> +	struct pglist_data *pgdat = data;
>> +	int cpu;
>> +
>> +	for_each_present_cpu(cpu) {
>> +		if (cpu_to_node(cpu) == pgdat->node_id)
>> +			/*
>> +			 * the cpu on this node isn't removed, and we can't
>> +			 * offline this node.
>> +			 */
>> +			return -EBUSY;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +/* offline the node if all memory sections of this node are removed */
>> +static void try_offline_node(int nid)
>> +{
>> +	unsigned long start_pfn = NODE_DATA(nid)->node_start_pfn;
>> +	unsigned long end_pfn = start_pfn + NODE_DATA(nid)->node_spanned_pages;
>> +	unsigned long pfn;
>> +
>> +	for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
>> +		unsigned long section_nr = pfn_to_section_nr(pfn);
>> +
>> +		if (!present_section_nr(section_nr))
>> +			continue;
>> +
>> +		if (pfn_to_nid(pfn) != nid)
>> +			continue;
>> +
>> +		/*
>> +		 * some memory sections of this node are not removed, and we
>> +		 * can't offline node now.
>> +		 */
>> +		return;
>> +	}
>> +
>> +	if (stop_machine(check_cpu_on_node, NODE_DATA(nid), NULL))
>> +		return;
> 
> how about:
> 	if (nr_cpus_node(nid))

If all cpus on the node is offlined, but not removed, nr_cpus_node(nid) will
return 0. In this case, we still can't offline the node.

Another purpose to use stop_machine() is to prevent cpu hotplug. We can't lock
cpuhotplug here.

Thanks
Wen Congyang

> 		return;
>> +
>> +	/*
>> +	 * all memory/cpu of this node are removed, we can offline this
>> +	 * node now.
>> +	 */
>> +	node_set_offline(nid);
>> +	unregister_one_node(nid);
>> +}
>> +
>> +int __ref remove_memory(int nid, u64 start, u64 size)
>>  {
>>  	unsigned long start_pfn, end_pfn;
>>  	int ret = 0;
>> @@ -1346,6 +1398,8 @@ repeat:
>>  
>>  	arch_remove_memory(start, size);
>>  
>> +	try_offline_node(nid);
>> +
>>  	unlock_memory_hotplug();
>>  
>>  	return 0;
>> @@ -1355,7 +1409,7 @@ int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
>>  {
>>  	return -EINVAL;
>>  }
>> -int remove_memory(u64 start, u64 size)
>> +int remove_memory(int nid, u64 start, u64 size)
>>  {
>>  	return -EINVAL;
>>  }
>>
> 
> 

[PATCH v3 12/12] memory-hotplug: free node_data when a node is offlined

[Wen Congyang]

We call hotadd_new_pgdat() to allocate memory to store node_data. So we
should free it when removing a node.

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>
CC: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
---
 mm/memory_hotplug.c | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index d965da3..e281c31 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1320,9 +1320,12 @@ static int check_cpu_on_node(void *data)
 /* offline the node if all memory sections of this node are removed */
 static void try_offline_node(int nid)
 {
+	pg_data_t *pgdat = NODE_DATA(nid);
 	unsigned long start_pfn = NODE_DATA(nid)->node_start_pfn;
-	unsigned long end_pfn = start_pfn + NODE_DATA(nid)->node_spanned_pages;
+	unsigned long end_pfn = start_pfn + pgdat->node_spanned_pages;
 	unsigned long pfn;
+	struct page *pgdat_page = virt_to_page(pgdat);
+	int i;
 
 	for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
 		unsigned long section_nr = pfn_to_section_nr(pfn);
@@ -1349,6 +1352,21 @@ static void try_offline_node(int nid)
 	 */
 	node_set_offline(nid);
 	unregister_one_node(nid);
+
+	if (!PageSlab(pgdat_page) && !PageCompound(pgdat_page))
+		/* node data is allocated from boot memory */
+		return;
+
+	/* free waittable in each zone */
+	for (i = 0; i < MAX_NR_ZONES; i++) {
+		struct zone *zone = pgdat->node_zones + i;
+
+		if (zone->wait_table)
+			vfree(zone->wait_table);
+	}
+
+	arch_refresh_nodedata(nid, NULL);
+	arch_free_nodedata(pgdat);
 }
 
 int __ref remove_memory(int nid, u64 start, u64 size)
-- 
1.8.0

Re: [PATCH v3 00/12] memory-hotplug: hot-remove physical memory

[Wen Congyang]

Ping

At 11/01/2012 05:44 PM, Wen Congyang Wrote:
> The patch-set was divided from following thread's patch-set.
>     https://lkml.org/lkml/2012/9/5/201
> 
> The last version of this patchset:
>     https://lkml.org/lkml/2012/10/23/213
> 
> If you want to know the reason, please read following thread.
> 
> https://lkml.org/lkml/2012/10/2/83
> 
> The patch-set has only the function of kernel core side for physical
> memory hot remove. So if you use the patch, please apply following
> patches.
> 
> - bug fix for memory hot remove
>   https://lkml.org/lkml/2012/10/31/269
>   
> - acpi framework
>   https://lkml.org/lkml/2012/10/26/175
> 
> The patches can free/remove the following things:
> 
>   - /sys/firmware/memmap/X/{end, start, type} : [PATCH 2/10]
>   - mem_section and related sysfs files       : [PATCH 3-4/10]
>   - memmap of sparse-vmemmap                  : [PATCH 5-7/10]
>   - page table of removed memory              : [RFC PATCH 8/10]
>   - node and related sysfs files              : [RFC PATCH 9-10/10]
> 
> * [PATCH 2/10] checks whether the memory can be removed or not.
> 
> 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
> 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. 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
> 
> 
> Changelogs from v2 to v3:
>  Patch9: call sync_global_pgds() if pgd is changed
>  Patch10: fix a problem int the patch
> 
> Changelogs from v1 to v2:
>  Patch1: new patch, offline memory twice. 1st iterate: offline every non primary
>          memory block. 2nd iterate: offline primary (i.e. first added) memory
>          block.
> 
>  Patch3: new patch, no logical change, just remove reduntant codes.
> 
>  Patch9: merge the patch from wujianguo into this patch. flush tlb on all cpu
>          after the pagetable is changed.
> 
>  Patch12: new patch, free node_data when a node is offlined
> 
> Wen Congyang (6):
>   memory-hotplug: try to offline the memory twice to avoid dependence
>   memory-hotplug: remove redundant codes
>   memory-hotplug: introduce new function arch_remove_memory() for
>     removing page table depends on architecture
>   memory-hotplug: remove page table of x86_64 architecture
>   memory-hotplug: remove sysfs file of node
>   memory-hotplug: free node_data when a node is offlined
> 
> Yasuaki Ishimatsu (6):
>   memory-hotplug: check whether all memory blocks are offlined or not
>     when removing memory
>   memory-hotplug: remove /sys/firmware/memmap/X sysfs
>   memory-hotplug: unregister memory section on SPARSEMEM_VMEMMAP
>   memory-hotplug: implement register_page_bootmem_info_section of
>     sparse-vmemmap
>   memory-hotplug: remove memmap of sparse-vmemmap
>   memory-hotplug: memory_hotplug: clear zone when removing the memory
> 
>  arch/ia64/mm/discontig.c             |  14 ++
>  arch/ia64/mm/init.c                  |  18 ++
>  arch/powerpc/mm/init_64.c            |  14 ++
>  arch/powerpc/mm/mem.c                |  12 +
>  arch/s390/mm/init.c                  |  12 +
>  arch/s390/mm/vmem.c                  |  14 ++
>  arch/sh/mm/init.c                    |  17 ++
>  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                |  12 +
>  arch/x86/mm/init_64.c                | 417 +++++++++++++++++++++++++++++++++++
>  arch/x86/mm/pageattr.c               |  47 ++--
>  drivers/acpi/acpi_memhotplug.c       |   8 +-
>  drivers/base/memory.c                |   6 +
>  drivers/firmware/memmap.c            |  98 +++++++-
>  include/linux/firmware-map.h         |   6 +
>  include/linux/memory_hotplug.h       |  15 +-
>  include/linux/mm.h                   |   5 +-
>  mm/memory_hotplug.c                  | 409 ++++++++++++++++++++++++++++++++--
>  mm/sparse.c                          |   5 +-
>  21 files changed, 1095 insertions(+), 57 deletions(-)
> 

Re: [PATCH v3 00/12] memory-hotplug: hot-remove physical memory

[Yasuaki Ishimatsu]

Hi Andrew,

The patch-set aims to linux-3.8. So we would like you to merge
the patch-set into your tree.

The patch-set applied many comments. Currently there is no
comment to the patch-set.

Additionally, we have spent a lot of time on the verification
of the patch-set. And we found many bugs, and fixed them.

So we believe that Linux on x86_64 can support memory hot remove
by the patch-set. 

Thanks,
Yasuaki Ishimatsu

2012/11/01 18:44, Wen Congyang wrote:
> The patch-set was divided from following thread's patch-set.
>      https://lkml.org/lkml/2012/9/5/201
> 
> The last version of this patchset:
>      https://lkml.org/lkml/2012/10/23/213
> 
> If you want to know the reason, please read following thread.
> 
> https://lkml.org/lkml/2012/10/2/83
> 
> The patch-set has only the function of kernel core side for physical
> memory hot remove. So if you use the patch, please apply following
> patches.
> 
> - bug fix for memory hot remove
>    https://lkml.org/lkml/2012/10/31/269
>    
> - acpi framework
>    https://lkml.org/lkml/2012/10/26/175
> 
> The patches can free/remove the following things:
> 
>    - /sys/firmware/memmap/X/{end, start, type} : [PATCH 2/10]
>    - mem_section and related sysfs files       : [PATCH 3-4/10]
>    - memmap of sparse-vmemmap                  : [PATCH 5-7/10]
>    - page table of removed memory              : [RFC PATCH 8/10]
>    - node and related sysfs files              : [RFC PATCH 9-10/10]
> 
> * [PATCH 2/10] checks whether the memory can be removed or not.
> 
> 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
> 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. 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
> 
> 
> Changelogs from v2 to v3:
>   Patch9: call sync_global_pgds() if pgd is changed
>   Patch10: fix a problem int the patch
> 
> Changelogs from v1 to v2:
>   Patch1: new patch, offline memory twice. 1st iterate: offline every non primary
>           memory block. 2nd iterate: offline primary (i.e. first added) memory
>           block.
> 
>   Patch3: new patch, no logical change, just remove reduntant codes.
> 
>   Patch9: merge the patch from wujianguo into this patch. flush tlb on all cpu
>           after the pagetable is changed.
> 
>   Patch12: new patch, free node_data when a node is offlined
> 
> Wen Congyang (6):
>    memory-hotplug: try to offline the memory twice to avoid dependence
>    memory-hotplug: remove redundant codes
>    memory-hotplug: introduce new function arch_remove_memory() for
>      removing page table depends on architecture
>    memory-hotplug: remove page table of x86_64 architecture
>    memory-hotplug: remove sysfs file of node
>    memory-hotplug: free node_data when a node is offlined
> 
> Yasuaki Ishimatsu (6):
>    memory-hotplug: check whether all memory blocks are offlined or not
>      when removing memory
>    memory-hotplug: remove /sys/firmware/memmap/X sysfs
>    memory-hotplug: unregister memory section on SPARSEMEM_VMEMMAP
>    memory-hotplug: implement register_page_bootmem_info_section of
>      sparse-vmemmap
>    memory-hotplug: remove memmap of sparse-vmemmap
>    memory-hotplug: memory_hotplug: clear zone when removing the memory
> 
>   arch/ia64/mm/discontig.c             |  14 ++
>   arch/ia64/mm/init.c                  |  18 ++
>   arch/powerpc/mm/init_64.c            |  14 ++
>   arch/powerpc/mm/mem.c                |  12 +
>   arch/s390/mm/init.c                  |  12 +
>   arch/s390/mm/vmem.c                  |  14 ++
>   arch/sh/mm/init.c                    |  17 ++
>   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                |  12 +
>   arch/x86/mm/init_64.c                | 417 +++++++++++++++++++++++++++++++++++
>   arch/x86/mm/pageattr.c               |  47 ++--
>   drivers/acpi/acpi_memhotplug.c       |   8 +-
>   drivers/base/memory.c                |   6 +
>   drivers/firmware/memmap.c            |  98 +++++++-
>   include/linux/firmware-map.h         |   6 +
>   include/linux/memory_hotplug.h       |  15 +-
>   include/linux/mm.h                   |   5 +-
>   mm/memory_hotplug.c                  | 409 ++++++++++++++++++++++++++++++++--
>   mm/sparse.c                          |   5 +-
>   21 files changed, 1095 insertions(+), 57 deletions(-)
>