1 files changed, 692 insertions, 0 deletions

diff --git a/drivers/base/node.c b/drivers/base/node.c
new file mode 100644
index 000000000..60c2e32f9
--- /dev/null
+++ b/drivers/base/node.c
@@ -0,0 +1,692 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Basic Node interface support
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/memory.h>
+#include <linux/vmstat.h>
+#include <linux/notifier.h>
+#include <linux/node.h>
+#include <linux/hugetlb.h>
+#include <linux/compaction.h>
+#include <linux/cpumask.h>
+#include <linux/topology.h>
+#include <linux/nodemask.h>
+#include <linux/cpu.h>
+#include <linux/device.h>
+#include <linux/swap.h>
+#include <linux/slab.h>
+
+static struct bus_type node_subsys = {
+	.name = "node",
+	.dev_name = "node",
+};
+
+
+static ssize_t node_read_cpumap(struct device *dev, bool list, char *buf)
+{
+	ssize_t n;
+	cpumask_var_t mask;
+	struct node *node_dev = to_node(dev);
+
+	/* 2008/04/07: buf currently PAGE_SIZE, need 9 chars per 32 bits. */
+	BUILD_BUG_ON((NR_CPUS/32 * 9) > (PAGE_SIZE-1));
+
+	if (!alloc_cpumask_var(&mask, GFP_KERNEL))
+		return 0;
+
+	cpumask_and(mask, cpumask_of_node(node_dev->dev.id), cpu_online_mask);
+	n = cpumap_print_to_pagebuf(list, buf, mask);
+	free_cpumask_var(mask);
+
+	return n;
+}
+
+static inline ssize_t node_read_cpumask(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	return node_read_cpumap(dev, false, buf);
+}
+static inline ssize_t node_read_cpulist(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	return node_read_cpumap(dev, true, buf);
+}
+
+static DEVICE_ATTR(cpumap,  S_IRUGO, node_read_cpumask, NULL);
+static DEVICE_ATTR(cpulist, S_IRUGO, node_read_cpulist, NULL);
+
+#define K(x) ((x) << (PAGE_SHIFT - 10))
+static ssize_t node_read_meminfo(struct device *dev,
+			struct device_attribute *attr, char *buf)
+{
+	int n;
+	int nid = dev->id;
+	struct pglist_data *pgdat = NODE_DATA(nid);
+	struct sysinfo i;
+
+	si_meminfo_node(&i, nid);
+	n = sprintf(buf,
+		       "Node %d MemTotal:       %8lu kB\n"
+		       "Node %d MemFree:        %8lu kB\n"
+		       "Node %d MemUsed:        %8lu kB\n"
+		       "Node %d Active:         %8lu kB\n"
+		       "Node %d Inactive:       %8lu kB\n"
+		       "Node %d Active(anon):   %8lu kB\n"
+		       "Node %d Inactive(anon): %8lu kB\n"
+		       "Node %d Active(file):   %8lu kB\n"
+		       "Node %d Inactive(file): %8lu kB\n"
+		       "Node %d Unevictable:    %8lu kB\n"
+		       "Node %d Mlocked:        %8lu kB\n",
+		       nid, K(i.totalram),
+		       nid, K(i.freeram),
+		       nid, K(i.totalram - i.freeram),
+		       nid, K(node_page_state(pgdat, NR_ACTIVE_ANON) +
+				node_page_state(pgdat, NR_ACTIVE_FILE)),
+		       nid, K(node_page_state(pgdat, NR_INACTIVE_ANON) +
+				node_page_state(pgdat, NR_INACTIVE_FILE)),
+		       nid, K(node_page_state(pgdat, NR_ACTIVE_ANON)),
+		       nid, K(node_page_state(pgdat, NR_INACTIVE_ANON)),
+		       nid, K(node_page_state(pgdat, NR_ACTIVE_FILE)),
+		       nid, K(node_page_state(pgdat, NR_INACTIVE_FILE)),
+		       nid, K(node_page_state(pgdat, NR_UNEVICTABLE)),
+		       nid, K(sum_zone_node_page_state(nid, NR_MLOCK)));
+
+#ifdef CONFIG_HIGHMEM
+	n += sprintf(buf + n,
+		       "Node %d HighTotal:      %8lu kB\n"
+		       "Node %d HighFree:       %8lu kB\n"
+		       "Node %d LowTotal:       %8lu kB\n"
+		       "Node %d LowFree:        %8lu kB\n",
+		       nid, K(i.totalhigh),
+		       nid, K(i.freehigh),
+		       nid, K(i.totalram - i.totalhigh),
+		       nid, K(i.freeram - i.freehigh));
+#endif
+	n += sprintf(buf + n,
+		       "Node %d Dirty:          %8lu kB\n"
+		       "Node %d Writeback:      %8lu kB\n"
+		       "Node %d FilePages:      %8lu kB\n"
+		       "Node %d Mapped:         %8lu kB\n"
+		       "Node %d AnonPages:      %8lu kB\n"
+		       "Node %d Shmem:          %8lu kB\n"
+		       "Node %d KernelStack:    %8lu kB\n"
+		       "Node %d PageTables:     %8lu kB\n"
+		       "Node %d NFS_Unstable:   %8lu kB\n"
+		       "Node %d Bounce:         %8lu kB\n"
+		       "Node %d WritebackTmp:   %8lu kB\n"
+		       "Node %d Slab:           %8lu kB\n"
+		       "Node %d SReclaimable:   %8lu kB\n"
+		       "Node %d SUnreclaim:     %8lu kB\n"
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+		       "Node %d AnonHugePages:  %8lu kB\n"
+		       "Node %d ShmemHugePages: %8lu kB\n"
+		       "Node %d ShmemPmdMapped: %8lu kB\n"
+#endif
+			,
+		       nid, K(node_page_state(pgdat, NR_FILE_DIRTY)),
+		       nid, K(node_page_state(pgdat, NR_WRITEBACK)),
+		       nid, K(node_page_state(pgdat, NR_FILE_PAGES)),
+		       nid, K(node_page_state(pgdat, NR_FILE_MAPPED)),
+		       nid, K(node_page_state(pgdat, NR_ANON_MAPPED)),
+		       nid, K(i.sharedram),
+		       nid, sum_zone_node_page_state(nid, NR_KERNEL_STACK_KB),
+		       nid, K(sum_zone_node_page_state(nid, NR_PAGETABLE)),
+		       nid, K(node_page_state(pgdat, NR_UNSTABLE_NFS)),
+		       nid, K(sum_zone_node_page_state(nid, NR_BOUNCE)),
+		       nid, K(node_page_state(pgdat, NR_WRITEBACK_TEMP)),
+		       nid, K(node_page_state(pgdat, NR_SLAB_RECLAIMABLE) +
+			      node_page_state(pgdat, NR_SLAB_UNRECLAIMABLE)),
+		       nid, K(node_page_state(pgdat, NR_SLAB_RECLAIMABLE)),
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+		       nid, K(node_page_state(pgdat, NR_SLAB_UNRECLAIMABLE)),
+		       nid, K(node_page_state(pgdat, NR_ANON_THPS) *
+				       HPAGE_PMD_NR),
+		       nid, K(node_page_state(pgdat, NR_SHMEM_THPS) *
+				       HPAGE_PMD_NR),
+		       nid, K(node_page_state(pgdat, NR_SHMEM_PMDMAPPED) *
+				       HPAGE_PMD_NR));
+#else
+		       nid, K(node_page_state(pgdat, NR_SLAB_UNRECLAIMABLE)));
+#endif
+	n += hugetlb_report_node_meminfo(nid, buf + n);
+	return n;
+}
+
+#undef K
+static DEVICE_ATTR(meminfo, S_IRUGO, node_read_meminfo, NULL);
+
+static ssize_t node_read_numastat(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	return sprintf(buf,
+		       "numa_hit %lu\n"
+		       "numa_miss %lu\n"
+		       "numa_foreign %lu\n"
+		       "interleave_hit %lu\n"
+		       "local_node %lu\n"
+		       "other_node %lu\n",
+		       sum_zone_numa_state(dev->id, NUMA_HIT),
+		       sum_zone_numa_state(dev->id, NUMA_MISS),
+		       sum_zone_numa_state(dev->id, NUMA_FOREIGN),
+		       sum_zone_numa_state(dev->id, NUMA_INTERLEAVE_HIT),
+		       sum_zone_numa_state(dev->id, NUMA_LOCAL),
+		       sum_zone_numa_state(dev->id, NUMA_OTHER));
+}
+static DEVICE_ATTR(numastat, S_IRUGO, node_read_numastat, NULL);
+
+static ssize_t node_read_vmstat(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	int nid = dev->id;
+	struct pglist_data *pgdat = NODE_DATA(nid);
+	int i;
+	int n = 0;
+
+	for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
+		n += sprintf(buf+n, "%s %lu\n", vmstat_text[i],
+			     sum_zone_node_page_state(nid, i));
+
+#ifdef CONFIG_NUMA
+	for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++)
+		n += sprintf(buf+n, "%s %lu\n",
+			     vmstat_text[i + NR_VM_ZONE_STAT_ITEMS],
+			     sum_zone_numa_state(nid, i));
+#endif
+
+	for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
+		/* Skip hidden vmstat items. */
+		if (*vmstat_text[i + NR_VM_ZONE_STAT_ITEMS +
+				 NR_VM_NUMA_STAT_ITEMS] == '\0')
+			continue;
+		n += sprintf(buf+n, "%s %lu\n",
+			     vmstat_text[i + NR_VM_ZONE_STAT_ITEMS +
+			     NR_VM_NUMA_STAT_ITEMS],
+			     node_page_state(pgdat, i));
+	}
+
+	return n;
+}
+static DEVICE_ATTR(vmstat, S_IRUGO, node_read_vmstat, NULL);
+
+static ssize_t node_read_distance(struct device *dev,
+			struct device_attribute *attr, char *buf)
+{
+	int nid = dev->id;
+	int len = 0;
+	int i;
+
+	/*
+	 * buf is currently PAGE_SIZE in length and each node needs 4 chars
+	 * at the most (distance + space or newline).
+	 */
+	BUILD_BUG_ON(MAX_NUMNODES * 4 > PAGE_SIZE);
+
+	for_each_online_node(i)
+		len += sprintf(buf + len, "%s%d", i ? " " : "", node_distance(nid, i));
+
+	len += sprintf(buf + len, "\n");
+	return len;
+}
+static DEVICE_ATTR(distance, S_IRUGO, node_read_distance, NULL);
+
+static struct attribute *node_dev_attrs[] = {
+	&dev_attr_cpumap.attr,
+	&dev_attr_cpulist.attr,
+	&dev_attr_meminfo.attr,
+	&dev_attr_numastat.attr,
+	&dev_attr_distance.attr,
+	&dev_attr_vmstat.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(node_dev);
+
+#ifdef CONFIG_HUGETLBFS
+/*
+ * hugetlbfs per node attributes registration interface:
+ * When/if hugetlb[fs] subsystem initializes [sometime after this module],
+ * it will register its per node attributes for all online nodes with
+ * memory.  It will also call register_hugetlbfs_with_node(), below, to
+ * register its attribute registration functions with this node driver.
+ * Once these hooks have been initialized, the node driver will call into
+ * the hugetlb module to [un]register attributes for hot-plugged nodes.
+ */
+static node_registration_func_t __hugetlb_register_node;
+static node_registration_func_t __hugetlb_unregister_node;
+
+static inline bool hugetlb_register_node(struct node *node)
+{
+	if (__hugetlb_register_node &&
+			node_state(node->dev.id, N_MEMORY)) {
+		__hugetlb_register_node(node);
+		return true;
+	}
+	return false;
+}
+
+static inline void hugetlb_unregister_node(struct node *node)
+{
+	if (__hugetlb_unregister_node)
+		__hugetlb_unregister_node(node);
+}
+
+void register_hugetlbfs_with_node(node_registration_func_t doregister,
+				  node_registration_func_t unregister)
+{
+	__hugetlb_register_node   = doregister;
+	__hugetlb_unregister_node = unregister;
+}
+#else
+static inline void hugetlb_register_node(struct node *node) {}
+
+static inline void hugetlb_unregister_node(struct node *node) {}
+#endif
+
+static void node_device_release(struct device *dev)
+{
+	struct node *node = to_node(dev);
+
+#if defined(CONFIG_MEMORY_HOTPLUG_SPARSE) && defined(CONFIG_HUGETLBFS)
+	/*
+	 * We schedule the work only when a memory section is
+	 * onlined/offlined on this node. When we come here,
+	 * all the memory on this node has been offlined,
+	 * so we won't enqueue new work to this work.
+	 *
+	 * The work is using node->node_work, so we should
+	 * flush work before freeing the memory.
+	 */
+	flush_work(&node->node_work);
+#endif
+	kfree(node);
+}
+
+/*
+ * register_node - Setup a sysfs device for a node.
+ * @num - Node number to use when creating the device.
+ *
+ * Initialize and register the node device.
+ */
+static int register_node(struct node *node, int num)
+{
+	int error;
+
+	node->dev.id = num;
+	node->dev.bus = &node_subsys;
+	node->dev.release = node_device_release;
+	node->dev.groups = node_dev_groups;
+	error = device_register(&node->dev);
+
+	if (error)
+		put_device(&node->dev);
+	else {
+		hugetlb_register_node(node);
+
+		compaction_register_node(node);
+	}
+	return error;
+}
+
+/**
+ * unregister_node - unregister a node device
+ * @node: node going away
+ *
+ * Unregisters a node device @node.  All the devices on the node must be
+ * unregistered before calling this function.
+ */
+void unregister_node(struct node *node)
+{
+	compaction_unregister_node(node);
+	hugetlb_unregister_node(node);		/* no-op, if memoryless node */
+
+	device_unregister(&node->dev);
+}
+
+struct node *node_devices[MAX_NUMNODES];
+
+/*
+ * register cpu under node
+ */
+int register_cpu_under_node(unsigned int cpu, unsigned int nid)
+{
+	int ret;
+	struct device *obj;
+
+	if (!node_online(nid))
+		return 0;
+
+	obj = get_cpu_device(cpu);
+	if (!obj)
+		return 0;
+
+	ret = sysfs_create_link(&node_devices[nid]->dev.kobj,
+				&obj->kobj,
+				kobject_name(&obj->kobj));
+	if (ret)
+		return ret;
+
+	return sysfs_create_link(&obj->kobj,
+				 &node_devices[nid]->dev.kobj,
+				 kobject_name(&node_devices[nid]->dev.kobj));
+}
+
+int unregister_cpu_under_node(unsigned int cpu, unsigned int nid)
+{
+	struct device *obj;
+
+	if (!node_online(nid))
+		return 0;
+
+	obj = get_cpu_device(cpu);
+	if (!obj)
+		return 0;
+
+	sysfs_remove_link(&node_devices[nid]->dev.kobj,
+			  kobject_name(&obj->kobj));
+	sysfs_remove_link(&obj->kobj,
+			  kobject_name(&node_devices[nid]->dev.kobj));
+
+	return 0;
+}
+
+#ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
+static int __ref get_nid_for_pfn(unsigned long pfn)
+{
+	if (!pfn_valid_within(pfn))
+		return -1;
+#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
+	if (system_state < SYSTEM_RUNNING)
+		return early_pfn_to_nid(pfn);
+#endif
+	return pfn_to_nid(pfn);
+}
+
+static int do_register_memory_block_under_node(int nid,
+					       struct memory_block *mem_blk)
+{
+	int ret;
+
+	/*
+	 * If this memory block spans multiple nodes, we only indicate
+	 * the last processed node.
+	 */
+	mem_blk->nid = nid;
+
+	ret = sysfs_create_link_nowarn(&node_devices[nid]->dev.kobj,
+				       &mem_blk->dev.kobj,
+				       kobject_name(&mem_blk->dev.kobj));
+	if (ret)
+		return ret;
+
+	return sysfs_create_link_nowarn(&mem_blk->dev.kobj,
+				&node_devices[nid]->dev.kobj,
+				kobject_name(&node_devices[nid]->dev.kobj));
+}
+
+/* register memory section under specified node if it spans that node */
+int register_mem_block_under_node_early(struct memory_block *mem_blk, void *arg)
+{
+	int nid = *(int *)arg;
+	unsigned long pfn, sect_start_pfn, sect_end_pfn;
+
+	sect_start_pfn = section_nr_to_pfn(mem_blk->start_section_nr);
+	sect_end_pfn = section_nr_to_pfn(mem_blk->end_section_nr);
+	sect_end_pfn += PAGES_PER_SECTION - 1;
+	for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
+		int page_nid;
+
+		/*
+		 * memory block could have several absent sections from start.
+		 * skip pfn range from absent section
+		 */
+		if (!pfn_present(pfn)) {
+			pfn = round_down(pfn + PAGES_PER_SECTION,
+					 PAGES_PER_SECTION) - 1;
+			continue;
+		}
+
+		/*
+		 * We need to check if page belongs to nid only at the boot
+		 * case because node's ranges can be interleaved.
+		 */
+		page_nid = get_nid_for_pfn(pfn);
+		if (page_nid < 0)
+			continue;
+		if (page_nid != nid)
+			continue;
+
+		return do_register_memory_block_under_node(nid, mem_blk);
+	}
+	/* mem section does not span the specified node */
+	return 0;
+}
+
+/*
+ * During hotplug we know that all pages in the memory block belong to the same
+ * node.
+ */
+static int register_mem_block_under_node_hotplug(struct memory_block *mem_blk,
+						 void *arg)
+{
+	int nid = *(int *)arg;
+
+	return do_register_memory_block_under_node(nid, mem_blk);
+}
+
+/*
+ * Unregister a memory block device under the node it spans. Memory blocks
+ * with multiple nodes cannot be offlined and therefore also never be removed.
+ */
+void unregister_memory_block_under_nodes(struct memory_block *mem_blk)
+{
+	if (mem_blk->nid == NUMA_NO_NODE)
+		return;
+
+	sysfs_remove_link(&node_devices[mem_blk->nid]->dev.kobj,
+			  kobject_name(&mem_blk->dev.kobj));
+	sysfs_remove_link(&mem_blk->dev.kobj,
+			  kobject_name(&node_devices[mem_blk->nid]->dev.kobj));
+}
+
+int link_mem_sections(int nid, unsigned long start_pfn, unsigned long end_pfn,
+		      enum meminit_context context)
+{
+	walk_memory_blocks_func_t func;
+
+	if (context == MEMINIT_HOTPLUG)
+		func = register_mem_block_under_node_hotplug;
+	else
+		func = register_mem_block_under_node_early;
+
+	return walk_memory_range(start_pfn, end_pfn, (void *)&nid, func);
+}
+
+#ifdef CONFIG_HUGETLBFS
+/*
+ * Handle per node hstate attribute [un]registration on transistions
+ * to/from memoryless state.
+ */
+static void node_hugetlb_work(struct work_struct *work)
+{
+	struct node *node = container_of(work, struct node, node_work);
+
+	/*
+	 * We only get here when a node transitions to/from memoryless state.
+	 * We can detect which transition occurred by examining whether the
+	 * node has memory now.  hugetlb_register_node() already check this
+	 * so we try to register the attributes.  If that fails, then the
+	 * node has transitioned to memoryless, try to unregister the
+	 * attributes.
+	 */
+	if (!hugetlb_register_node(node))
+		hugetlb_unregister_node(node);
+}
+
+static void init_node_hugetlb_work(int nid)
+{
+	INIT_WORK(&node_devices[nid]->node_work, node_hugetlb_work);
+}
+
+static int node_memory_callback(struct notifier_block *self,
+				unsigned long action, void *arg)
+{
+	struct memory_notify *mnb = arg;
+	int nid = mnb->status_change_nid;
+
+	switch (action) {
+	case MEM_ONLINE:
+	case MEM_OFFLINE:
+		/*
+		 * offload per node hstate [un]registration to a work thread
+		 * when transitioning to/from memoryless state.
+		 */
+		if (nid != NUMA_NO_NODE)
+			schedule_work(&node_devices[nid]->node_work);
+		break;
+
+	case MEM_GOING_ONLINE:
+	case MEM_GOING_OFFLINE:
+	case MEM_CANCEL_ONLINE:
+	case MEM_CANCEL_OFFLINE:
+	default:
+		break;
+	}
+
+	return NOTIFY_OK;
+}
+#endif	/* CONFIG_HUGETLBFS */
+#endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
+
+#if !defined(CONFIG_MEMORY_HOTPLUG_SPARSE) || \
+    !defined(CONFIG_HUGETLBFS)
+static inline int node_memory_callback(struct notifier_block *self,
+				unsigned long action, void *arg)
+{
+	return NOTIFY_OK;
+}
+
+static void init_node_hugetlb_work(int nid) { }
+
+#endif
+
+int __register_one_node(int nid)
+{
+	int error;
+	int cpu;
+
+	node_devices[nid] = kzalloc(sizeof(struct node), GFP_KERNEL);
+	if (!node_devices[nid])
+		return -ENOMEM;
+
+	error = register_node(node_devices[nid], nid);
+
+	/* link cpu under this node */
+	for_each_present_cpu(cpu) {
+		if (cpu_to_node(cpu) == nid)
+			register_cpu_under_node(cpu, nid);
+	}
+
+	/* initialize work queue for memory hot plug */
+	init_node_hugetlb_work(nid);
+
+	return error;
+}
+
+void unregister_one_node(int nid)
+{
+	if (!node_devices[nid])
+		return;
+
+	unregister_node(node_devices[nid]);
+	node_devices[nid] = NULL;
+}
+
+/*
+ * node states attributes
+ */
+
+static ssize_t print_nodes_state(enum node_states state, char *buf)
+{
+	int n;
+
+	n = scnprintf(buf, PAGE_SIZE - 1, "%*pbl",
+		      nodemask_pr_args(&node_states[state]));
+	buf[n++] = '\n';
+	buf[n] = '\0';
+	return n;
+}
+
+struct node_attr {
+	struct device_attribute attr;
+	enum node_states state;
+};
+
+static ssize_t show_node_state(struct device *dev,
+			       struct device_attribute *attr, char *buf)
+{
+	struct node_attr *na = container_of(attr, struct node_attr, attr);
+	return print_nodes_state(na->state, buf);
+}
+
+#define _NODE_ATTR(name, state) \
+	{ __ATTR(name, 0444, show_node_state, NULL), state }
+
+static struct node_attr node_state_attr[] = {
+	[N_POSSIBLE] = _NODE_ATTR(possible, N_POSSIBLE),
+	[N_ONLINE] = _NODE_ATTR(online, N_ONLINE),
+	[N_NORMAL_MEMORY] = _NODE_ATTR(has_normal_memory, N_NORMAL_MEMORY),
+#ifdef CONFIG_HIGHMEM
+	[N_HIGH_MEMORY] = _NODE_ATTR(has_high_memory, N_HIGH_MEMORY),
+#endif
+	[N_MEMORY] = _NODE_ATTR(has_memory, N_MEMORY),
+	[N_CPU] = _NODE_ATTR(has_cpu, N_CPU),
+};
+
+static struct attribute *node_state_attrs[] = {
+	&node_state_attr[N_POSSIBLE].attr.attr,
+	&node_state_attr[N_ONLINE].attr.attr,
+	&node_state_attr[N_NORMAL_MEMORY].attr.attr,
+#ifdef CONFIG_HIGHMEM
+	&node_state_attr[N_HIGH_MEMORY].attr.attr,
+#endif
+	&node_state_attr[N_MEMORY].attr.attr,
+	&node_state_attr[N_CPU].attr.attr,
+	NULL
+};
+
+static struct attribute_group memory_root_attr_group = {
+	.attrs = node_state_attrs,
+};
+
+static const struct attribute_group *cpu_root_attr_groups[] = {
+	&memory_root_attr_group,
+	NULL,
+};
+
+#define NODE_CALLBACK_PRI	2	/* lower than SLAB */
+static int __init register_node_type(void)
+{
+	int ret;
+
+ 	BUILD_BUG_ON(ARRAY_SIZE(node_state_attr) != NR_NODE_STATES);
+ 	BUILD_BUG_ON(ARRAY_SIZE(node_state_attrs)-1 != NR_NODE_STATES);
+
+	ret = subsys_system_register(&node_subsys, cpu_root_attr_groups);
+	if (!ret) {
+		static struct notifier_block node_memory_callback_nb = {
+			.notifier_call = node_memory_callback,
+			.priority = NODE_CALLBACK_PRI,
+		};
+		register_hotmemory_notifier(&node_memory_callback_nb);
+	}
+
+	/*
+	 * Note:  we're not going to unregister the node class if we fail
+	 * to register the node state class attribute files.
+	 */
+	return ret;
+}
+postcore_initcall(register_node_type);