memory hotplug: Allow memory blocks to span multiple memory sections (0c2c99b1) · Commits · 戴 / test

Documentation/memory-hotplug.txt

+31 −16

Original line number	Diff line number	Diff line
		@@ -126,36 +126,51 @@ config options.
		--------------------------------
		4 sysfs files for memory hotplug
		--------------------------------
		All sections have their device information under /sys/devices/system/memory as
		All sections have their device information in sysfs. Each section is part of
		a memory block under /sys/devices/system/memory as

		/sys/devices/system/memory/memoryXXX
		(XXX is section id.)
		(XXX is the section id.)

		Now, XXX is defined as start_address_of_section / section_size.
		Now, XXX is defined as (start_address_of_section / section_size) of the first
		section contained in the memory block. The files 'phys_index' and
		'end_phys_index' under each directory report the beginning and end section id's
		for the memory block covered by the sysfs directory. It is expected that all
		memory sections in this range are present and no memory holes exist in the
		range. Currently there is no way to determine if there is a memory hole, but
		the existence of one should not affect the hotplug capabilities of the memory
		block.

		For example, assume 1GiB section size. A device for a memory starting at
		0x100000000 is /sys/device/system/memory/memory4
		(0x100000000 / 1Gib = 4)
		This device covers address range [0x100000000 ... 0x140000000)

		Under each section, you can see 4 files.
		Under each section, you can see 4 or 5 files, the end_phys_index file being
		a recent addition and not present on older kernels.

		/sys/devices/system/memory/memoryXXX/phys_index
		/sys/devices/system/memory/memoryXXX/start_phys_index
		/sys/devices/system/memory/memoryXXX/end_phys_index
		/sys/devices/system/memory/memoryXXX/phys_device
		/sys/devices/system/memory/memoryXXX/state
		/sys/devices/system/memory/memoryXXX/removable

		'phys_index' : read-only and contains section id, same as XXX.
		'phys_index' : read-only and contains section id of the first section
		in the memory block, same as XXX.
		'end_phys_index' : read-only and contains section id of the last section
		in the memory block.
		'state' : read-write
		at read: contains online/offline state of memory.
		at write: user can specify "online", "offline" command
		'phys_device': read-only: designed to show the name of physical memory device.
		This is not well implemented now.
		which will be performed on al sections in the block.
		'phys_device' : read-only: designed to show the name of physical memory
		device. This is not well implemented now.
		'removable' : read-only: contains an integer value indicating
		whether the memory section is removable or not
		whether the memory block is removable or not
		removable. A value of 1 indicates that the memory
		section is removable and a value of 0 indicates that
		it is not removable.
		block is removable and a value of 0 indicates that
		it is not removable. A memory block is removable only if
		every section in the block is removable.

		NOTE:
		These directories/files appear after physical memory hotplug phase.

drivers/base/memory.c

+108 −47

Original line number	Diff line number	Diff line
		@@ -30,6 +30,14 @@
		static DEFINE_MUTEX(mem_sysfs_mutex);

		#define MEMORY_CLASS_NAME "memory"
		#define MIN_MEMORY_BLOCK_SIZE (1 << SECTION_SIZE_BITS)

		static int sections_per_block;

		static inline int base_memory_block_id(int section_nr)
		{
		return section_nr / sections_per_block;
		}

		static struct sysdev_class memory_sysdev_class = {
		.name = MEMORY_CLASS_NAME,
		@@ -84,28 +92,47 @@ EXPORT_SYMBOL(unregister_memory_isolate_notifier);
		* register_memory - Setup a sysfs device for a memory block
		*/
		static
		int register_memory(struct memory_block memory, struct mem_section section)
		int register_memory(struct memory_block *memory)
		{
		int error;

		memory->sysdev.cls = &memory_sysdev_class;
		memory->sysdev.id = __section_nr(section);
		memory->sysdev.id = memory->phys_index / sections_per_block;

		error = sysdev_register(&memory->sysdev);
		return error;
		}

		static void
		unregister_memory(struct memory_block memory, struct mem_section section)
		unregister_memory(struct memory_block *memory)
		{
		BUG_ON(memory->sysdev.cls != &memory_sysdev_class);
		BUG_ON(memory->sysdev.id != __section_nr(section));

		/* drop the ref. we got in remove_memory_block() */
		kobject_put(&memory->sysdev.kobj);
		sysdev_unregister(&memory->sysdev);
		}

		unsigned long __weak memory_block_size_bytes(void)
		{
		return MIN_MEMORY_BLOCK_SIZE;
		}

		static unsigned long get_memory_block_size(void)
		{
		unsigned long block_sz;

		block_sz = memory_block_size_bytes();

		/* Validate blk_sz is a power of 2 and not less than section size */
		if ((block_sz & (block_sz - 1)) \|\| (block_sz < MIN_MEMORY_BLOCK_SIZE)) {
		WARN_ON(1);
		block_sz = MIN_MEMORY_BLOCK_SIZE;
		}

		return block_sz;
		}

		/*
		* use this as the physical section index that this memsection
		* uses.
		@@ -116,7 +143,7 @@ static ssize_t show_mem_phys_index(struct sys_device *dev,
		{
		struct memory_block *mem =
		container_of(dev, struct memory_block, sysdev);
		return sprintf(buf, "%08lx\n", mem->phys_index);
		return sprintf(buf, "%08lx\n", mem->phys_index / sections_per_block);
		}

		/*
		@@ -125,13 +152,16 @@ static ssize_t show_mem_phys_index(struct sys_device *dev,
		static ssize_t show_mem_removable(struct sys_device *dev,
		struct sysdev_attribute attr, char buf)
		{
		unsigned long start_pfn;
		int ret;
		unsigned long i, pfn;
		int ret = 1;
		struct memory_block *mem =
		container_of(dev, struct memory_block, sysdev);

		start_pfn = section_nr_to_pfn(mem->phys_index);
		ret = is_mem_section_removable(start_pfn, PAGES_PER_SECTION);
		for (i = 0; i < sections_per_block; i++) {
		pfn = section_nr_to_pfn(mem->phys_index + i);
		ret &= is_mem_section_removable(pfn, PAGES_PER_SECTION);
		}

		return sprintf(buf, "%d\n", ret);
		}

		@@ -184,17 +214,14 @@ int memory_isolate_notify(unsigned long val, void *v)
		* OK to have direct references to sparsemem variables in here.
		*/
		static int
		memory_block_action(struct memory_block *mem, unsigned long action)
		memory_section_action(unsigned long phys_index, unsigned long action)
		{
		int i;
		unsigned long psection;
		unsigned long start_pfn, start_paddr;
		struct page *first_page;
		int ret;
		int old_state = mem->state;

		psection = mem->phys_index;
		first_page = pfn_to_page(psection << PFN_SECTION_SHIFT);
		first_page = pfn_to_page(phys_index << PFN_SECTION_SHIFT);

		/*
		* The probe routines leave the pages reserved, just
		@@ -208,7 +235,7 @@ memory_block_action(struct memory_block *mem, unsigned long action)

		printk(KERN_WARNING "section number %ld page number %d "
		"not reserved, was it already online?\n",
		psection, i);
		phys_index, i);
		return -EBUSY;
		}
		}
		@@ -219,18 +246,13 @@ memory_block_action(struct memory_block *mem, unsigned long action)
		ret = online_pages(start_pfn, PAGES_PER_SECTION);
		break;
		case MEM_OFFLINE:
		mem->state = MEM_GOING_OFFLINE;
		start_paddr = page_to_pfn(first_page) << PAGE_SHIFT;
		ret = remove_memory(start_paddr,
		PAGES_PER_SECTION << PAGE_SHIFT);
		if (ret) {
		mem->state = old_state;
		break;
		}
		break;
		default:
		WARN(1, KERN_WARNING "%s(%p, %ld) unknown action: %ld\n",
		__func__, mem, action, action);
		WARN(1, KERN_WARNING "%s(%ld, %ld) unknown action: "
		"%ld\n", __func__, phys_index, action, action);
		ret = -EINVAL;
		}

		@@ -240,7 +262,8 @@ memory_block_action(struct memory_block *mem, unsigned long action)
		static int memory_block_change_state(struct memory_block *mem,
		unsigned long to_state, unsigned long from_state_req)
		{
		int ret = 0;
		int i, ret = 0;

		mutex_lock(&mem->state_mutex);

		if (mem->state != from_state_req) {
		@@ -248,8 +271,22 @@ static int memory_block_change_state(struct memory_block *mem,
		goto out;
		}

		ret = memory_block_action(mem, to_state);
		if (!ret)
		if (to_state == MEM_OFFLINE)
		mem->state = MEM_GOING_OFFLINE;

		for (i = 0; i < sections_per_block; i++) {
		ret = memory_section_action(mem->phys_index + i, to_state);
		if (ret)
		break;
		}

		if (ret) {
		for (i = 0; i < sections_per_block; i++)
		memory_section_action(mem->phys_index + i,
		from_state_req);

		mem->state = from_state_req;
		} else
		mem->state = to_state;

		out:
		@@ -262,20 +299,15 @@ store_mem_state(struct sys_device *dev,
		struct sysdev_attribute attr, const char buf, size_t count)
		{
		struct memory_block *mem;
		unsigned int phys_section_nr;
		int ret = -EINVAL;

		mem = container_of(dev, struct memory_block, sysdev);
		phys_section_nr = mem->phys_index;

		if (!present_section_nr(phys_section_nr))
		goto out;

		if (!strncmp(buf, "online", min((int)count, 6)))
		ret = memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE);
		else if(!strncmp(buf, "offline", min((int)count, 7)))
		ret = memory_block_change_state(mem, MEM_OFFLINE, MEM_ONLINE);
		out:

		if (ret)
		return ret;
		return count;
		@@ -315,7 +347,7 @@ static ssize_t
		print_block_size(struct sysdev_class class, struct sysdev_class_attribute attr,
		char *buf)
		{
		return sprintf(buf, "%lx\n", (unsigned long)PAGES_PER_SECTION * PAGE_SIZE);
		return sprintf(buf, "%lx\n", get_memory_block_size());
		}

		static SYSDEV_CLASS_ATTR(block_size_bytes, 0444, print_block_size, NULL);
		@@ -444,6 +476,7 @@ struct memory_block find_memory_block_hinted(struct mem_section section,
		struct sys_device *sysdev;
		struct memory_block *mem;
		char name[sizeof(MEMORY_CLASS_NAME) + 9 + 1];
		int block_id = base_memory_block_id(__section_nr(section));

		kobj = hint ? &hint->sysdev.kobj : NULL;

		@@ -451,7 +484,7 @@ struct memory_block find_memory_block_hinted(struct mem_section section,
		* This only works because we know that section == sysdev->id
		* slightly redundant with sysdev_register()
		*/
		sprintf(&name[0], "%s%d", MEMORY_CLASS_NAME, __section_nr(section));
		sprintf(&name[0], "%s%d", MEMORY_CLASS_NAME, block_id);

		kobj = kset_find_obj_hinted(&memory_sysdev_class.kset, name, kobj);
		if (!kobj)
		@@ -476,26 +509,27 @@ struct memory_block find_memory_block(struct mem_section section)
		return find_memory_block_hinted(section, NULL);
		}

		static int add_memory_block(int nid, struct mem_section *section,
		unsigned long state, enum mem_add_context context)
		static int init_memory_block(struct memory_block **memory,
		struct mem_section *section, unsigned long state)
		{
		struct memory_block mem = kzalloc(sizeof(mem), GFP_KERNEL);
		struct memory_block *mem;
		unsigned long start_pfn;
		int scn_nr;
		int ret = 0;

		mem = kzalloc(sizeof(*mem), GFP_KERNEL);
		if (!mem)
		return -ENOMEM;

		mutex_lock(&mem_sysfs_mutex);

		mem->phys_index = __section_nr(section);
		scn_nr = __section_nr(section);
		mem->phys_index = base_memory_block_id(scn_nr) * sections_per_block;
		mem->state = state;
		mem->section_count++;
		mutex_init(&mem->state_mutex);
		start_pfn = section_nr_to_pfn(mem->phys_index);
		mem->phys_device = arch_get_memory_phys_device(start_pfn);

		ret = register_memory(mem, section);
		ret = register_memory(mem);
		if (!ret)
		ret = mem_create_simple_file(mem, phys_index);
		if (!ret)
		@@ -504,8 +538,29 @@ static int add_memory_block(int nid, struct mem_section *section,
		ret = mem_create_simple_file(mem, phys_device);
		if (!ret)
		ret = mem_create_simple_file(mem, removable);

		*memory = mem;
		return ret;
		}

		static int add_memory_section(int nid, struct mem_section *section,
		unsigned long state, enum mem_add_context context)
		{
		struct memory_block *mem;
		int ret = 0;

		mutex_lock(&mem_sysfs_mutex);

		mem = find_memory_block(section);
		if (mem) {
		mem->section_count++;
		kobject_put(&mem->sysdev.kobj);
		} else
		ret = init_memory_block(&mem, section, state);

		if (!ret) {
		if (context == HOTPLUG)
		if (context == HOTPLUG &&
		mem->section_count == sections_per_block)
		ret = register_mem_sect_under_node(mem, nid);
		}

		@@ -528,8 +583,10 @@ int remove_memory_block(unsigned long node_id, struct mem_section *section,
		mem_remove_simple_file(mem, state);
		mem_remove_simple_file(mem, phys_device);
		mem_remove_simple_file(mem, removable);
		unregister_memory(mem, section);
		}
		unregister_memory(mem);
		kfree(mem);
		} else
		kobject_put(&mem->sysdev.kobj);

		mutex_unlock(&mem_sysfs_mutex);
		return 0;
		@@ -541,7 +598,7 @@ int remove_memory_block(unsigned long node_id, struct mem_section *section,
		*/
		int register_new_memory(int nid, struct mem_section *section)
		{
		return add_memory_block(nid, section, MEM_OFFLINE, HOTPLUG);
		return add_memory_section(nid, section, MEM_OFFLINE, HOTPLUG);
		}

		int unregister_memory_section(struct mem_section *section)
		@@ -560,12 +617,16 @@ int __init memory_dev_init(void)
		unsigned int i;
		int ret;
		int err;
		unsigned long block_sz;

		memory_sysdev_class.kset.uevent_ops = &memory_uevent_ops;
		ret = sysdev_class_register(&memory_sysdev_class);
		if (ret)
		goto out;

		block_sz = get_memory_block_size();
		sections_per_block = block_sz / MIN_MEMORY_BLOCK_SIZE;

		/*
		* Create entries for memory sections that were found
		* during boot and have been initialized
		@@ -573,7 +634,7 @@ int __init memory_dev_init(void)
		for (i = 0; i < NR_MEM_SECTIONS; i++) {
		if (!present_section_nr(i))
		continue;
		err = add_memory_block(0, __nr_to_section(i), MEM_ONLINE,
		err = add_memory_section(0, __nr_to_section(i), MEM_ONLINE,
		BOOT);
		if (!ret)
		ret = err;

Admin message