Adding upstream version 5.10.209.upstream/5.10.209

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1067 insertions, 0 deletions

diff --git a/drivers/base/node.c b/drivers/base/node.c
new file mode 100644
index 000000000..5f745c906
--- /dev/null
+++ b/drivers/base/node.c
@@ -0,0 +1,1067 @@
+// 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/pm_runtime.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 cpumap_show(struct device *dev,
+				  struct device_attribute *attr,
+				  char *buf)
+{
+	return node_read_cpumap(dev, false, buf);
+}
+
+static DEVICE_ATTR_RO(cpumap);
+
+static inline ssize_t cpulist_show(struct device *dev,
+				   struct device_attribute *attr,
+				   char *buf)
+{
+	return node_read_cpumap(dev, true, buf);
+}
+
+static DEVICE_ATTR_RO(cpulist);
+
+/**
+ * struct node_access_nodes - Access class device to hold user visible
+ * 			      relationships to other nodes.
+ * @dev:	Device for this memory access class
+ * @list_node:	List element in the node's access list
+ * @access:	The access class rank
+ * @hmem_attrs: Heterogeneous memory performance attributes
+ */
+struct node_access_nodes {
+	struct device		dev;
+	struct list_head	list_node;
+	unsigned		access;
+#ifdef CONFIG_HMEM_REPORTING
+	struct node_hmem_attrs	hmem_attrs;
+#endif
+};
+#define to_access_nodes(dev) container_of(dev, struct node_access_nodes, dev)
+
+static struct attribute *node_init_access_node_attrs[] = {
+	NULL,
+};
+
+static struct attribute *node_targ_access_node_attrs[] = {
+	NULL,
+};
+
+static const struct attribute_group initiators = {
+	.name	= "initiators",
+	.attrs	= node_init_access_node_attrs,
+};
+
+static const struct attribute_group targets = {
+	.name	= "targets",
+	.attrs	= node_targ_access_node_attrs,
+};
+
+static const struct attribute_group *node_access_node_groups[] = {
+	&initiators,
+	&targets,
+	NULL,
+};
+
+static void node_remove_accesses(struct node *node)
+{
+	struct node_access_nodes *c, *cnext;
+
+	list_for_each_entry_safe(c, cnext, &node->access_list, list_node) {
+		list_del(&c->list_node);
+		device_unregister(&c->dev);
+	}
+}
+
+static void node_access_release(struct device *dev)
+{
+	kfree(to_access_nodes(dev));
+}
+
+static struct node_access_nodes *node_init_node_access(struct node *node,
+						       unsigned access)
+{
+	struct node_access_nodes *access_node;
+	struct device *dev;
+
+	list_for_each_entry(access_node, &node->access_list, list_node)
+		if (access_node->access == access)
+			return access_node;
+
+	access_node = kzalloc(sizeof(*access_node), GFP_KERNEL);
+	if (!access_node)
+		return NULL;
+
+	access_node->access = access;
+	dev = &access_node->dev;
+	dev->parent = &node->dev;
+	dev->release = node_access_release;
+	dev->groups = node_access_node_groups;
+	if (dev_set_name(dev, "access%u", access))
+		goto free;
+
+	if (device_register(dev))
+		goto free_name;
+
+	pm_runtime_no_callbacks(dev);
+	list_add_tail(&access_node->list_node, &node->access_list);
+	return access_node;
+free_name:
+	kfree_const(dev->kobj.name);
+free:
+	kfree(access_node);
+	return NULL;
+}
+
+#ifdef CONFIG_HMEM_REPORTING
+#define ACCESS_ATTR(name)						\
+static ssize_t name##_show(struct device *dev,				\
+			   struct device_attribute *attr,		\
+			   char *buf)					\
+{									\
+	return sysfs_emit(buf, "%u\n",					\
+			  to_access_nodes(dev)->hmem_attrs.name);	\
+}									\
+static DEVICE_ATTR_RO(name)
+
+ACCESS_ATTR(read_bandwidth);
+ACCESS_ATTR(read_latency);
+ACCESS_ATTR(write_bandwidth);
+ACCESS_ATTR(write_latency);
+
+static struct attribute *access_attrs[] = {
+	&dev_attr_read_bandwidth.attr,
+	&dev_attr_read_latency.attr,
+	&dev_attr_write_bandwidth.attr,
+	&dev_attr_write_latency.attr,
+	NULL,
+};
+
+/**
+ * node_set_perf_attrs - Set the performance values for given access class
+ * @nid: Node identifier to be set
+ * @hmem_attrs: Heterogeneous memory performance attributes
+ * @access: The access class the for the given attributes
+ */
+void node_set_perf_attrs(unsigned int nid, struct node_hmem_attrs *hmem_attrs,
+			 unsigned access)
+{
+	struct node_access_nodes *c;
+	struct node *node;
+	int i;
+
+	if (WARN_ON_ONCE(!node_online(nid)))
+		return;
+
+	node = node_devices[nid];
+	c = node_init_node_access(node, access);
+	if (!c)
+		return;
+
+	c->hmem_attrs = *hmem_attrs;
+	for (i = 0; access_attrs[i] != NULL; i++) {
+		if (sysfs_add_file_to_group(&c->dev.kobj, access_attrs[i],
+					    "initiators")) {
+			pr_info("failed to add performance attribute to node %d\n",
+				nid);
+			break;
+		}
+	}
+}
+
+/**
+ * struct node_cache_info - Internal tracking for memory node caches
+ * @dev:	Device represeting the cache level
+ * @node:	List element for tracking in the node
+ * @cache_attrs:Attributes for this cache level
+ */
+struct node_cache_info {
+	struct device dev;
+	struct list_head node;
+	struct node_cache_attrs cache_attrs;
+};
+#define to_cache_info(device) container_of(device, struct node_cache_info, dev)
+
+#define CACHE_ATTR(name, fmt) 						\
+static ssize_t name##_show(struct device *dev,				\
+			   struct device_attribute *attr,		\
+			   char *buf)					\
+{									\
+	return sysfs_emit(buf, fmt "\n",				\
+			  to_cache_info(dev)->cache_attrs.name);	\
+}									\
+DEVICE_ATTR_RO(name);
+
+CACHE_ATTR(size, "%llu")
+CACHE_ATTR(line_size, "%u")
+CACHE_ATTR(indexing, "%u")
+CACHE_ATTR(write_policy, "%u")
+
+static struct attribute *cache_attrs[] = {
+	&dev_attr_indexing.attr,
+	&dev_attr_size.attr,
+	&dev_attr_line_size.attr,
+	&dev_attr_write_policy.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(cache);
+
+static void node_cache_release(struct device *dev)
+{
+	kfree(dev);
+}
+
+static void node_cacheinfo_release(struct device *dev)
+{
+	struct node_cache_info *info = to_cache_info(dev);
+	kfree(info);
+}
+
+static void node_init_cache_dev(struct node *node)
+{
+	struct device *dev;
+
+	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+	if (!dev)
+		return;
+
+	device_initialize(dev);
+	dev->parent = &node->dev;
+	dev->release = node_cache_release;
+	if (dev_set_name(dev, "memory_side_cache"))
+		goto put_device;
+
+	if (device_add(dev))
+		goto put_device;
+
+	pm_runtime_no_callbacks(dev);
+	node->cache_dev = dev;
+	return;
+put_device:
+	put_device(dev);
+}
+
+/**
+ * node_add_cache() - add cache attribute to a memory node
+ * @nid: Node identifier that has new cache attributes
+ * @cache_attrs: Attributes for the cache being added
+ */
+void node_add_cache(unsigned int nid, struct node_cache_attrs *cache_attrs)
+{
+	struct node_cache_info *info;
+	struct device *dev;
+	struct node *node;
+
+	if (!node_online(nid) || !node_devices[nid])
+		return;
+
+	node = node_devices[nid];
+	list_for_each_entry(info, &node->cache_attrs, node) {
+		if (info->cache_attrs.level == cache_attrs->level) {
+			dev_warn(&node->dev,
+				"attempt to add duplicate cache level:%d\n",
+				cache_attrs->level);
+			return;
+		}
+	}
+
+	if (!node->cache_dev)
+		node_init_cache_dev(node);
+	if (!node->cache_dev)
+		return;
+
+	info = kzalloc(sizeof(*info), GFP_KERNEL);
+	if (!info)
+		return;
+
+	dev = &info->dev;
+	device_initialize(dev);
+	dev->parent = node->cache_dev;
+	dev->release = node_cacheinfo_release;
+	dev->groups = cache_groups;
+	if (dev_set_name(dev, "index%d", cache_attrs->level))
+		goto put_device;
+
+	info->cache_attrs = *cache_attrs;
+	if (device_add(dev)) {
+		dev_warn(&node->dev, "failed to add cache level:%d\n",
+			 cache_attrs->level);
+		goto put_device;
+	}
+	pm_runtime_no_callbacks(dev);
+	list_add_tail(&info->node, &node->cache_attrs);
+	return;
+put_device:
+	put_device(dev);
+}
+
+static void node_remove_caches(struct node *node)
+{
+	struct node_cache_info *info, *next;
+
+	if (!node->cache_dev)
+		return;
+
+	list_for_each_entry_safe(info, next, &node->cache_attrs, node) {
+		list_del(&info->node);
+		device_unregister(&info->dev);
+	}
+	device_unregister(node->cache_dev);
+}
+
+static void node_init_caches(unsigned int nid)
+{
+	INIT_LIST_HEAD(&node_devices[nid]->cache_attrs);
+}
+#else
+static void node_init_caches(unsigned int nid) { }
+static void node_remove_caches(struct node *node) { }
+#endif
+
+#define K(x) ((x) << (PAGE_SHIFT - 10))
+static ssize_t node_read_meminfo(struct device *dev,
+			struct device_attribute *attr, char *buf)
+{
+	int len = 0;
+	int nid = dev->id;
+	struct pglist_data *pgdat = NODE_DATA(nid);
+	struct sysinfo i;
+	unsigned long sreclaimable, sunreclaimable;
+
+	si_meminfo_node(&i, nid);
+	sreclaimable = node_page_state_pages(pgdat, NR_SLAB_RECLAIMABLE_B);
+	sunreclaimable = node_page_state_pages(pgdat, NR_SLAB_UNRECLAIMABLE_B);
+	len = sysfs_emit_at(buf, len,
+			    "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
+	len += sysfs_emit_at(buf, len,
+			     "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
+	len += sysfs_emit_at(buf, len,
+			     "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"
+#ifdef CONFIG_SHADOW_CALL_STACK
+			     "Node %d ShadowCallStack:%8lu kB\n"
+#endif
+			     "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 KReclaimable:   %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"
+			     "Node %d FileHugePages: %8lu kB\n"
+			     "Node %d FilePmdMapped: %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, node_page_state(pgdat, NR_KERNEL_STACK_KB),
+#ifdef CONFIG_SHADOW_CALL_STACK
+			     nid, node_page_state(pgdat, NR_KERNEL_SCS_KB),
+#endif
+			     nid, K(sum_zone_node_page_state(nid, NR_PAGETABLE)),
+			     nid, 0UL,
+			     nid, K(sum_zone_node_page_state(nid, NR_BOUNCE)),
+			     nid, K(node_page_state(pgdat, NR_WRITEBACK_TEMP)),
+			     nid, K(sreclaimable +
+				    node_page_state(pgdat, NR_KERNEL_MISC_RECLAIMABLE)),
+			     nid, K(sreclaimable + sunreclaimable),
+			     nid, K(sreclaimable),
+			     nid, K(sunreclaimable)
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+			     ,
+			     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),
+			     nid, K(node_page_state(pgdat, NR_FILE_THPS) *
+				    HPAGE_PMD_NR),
+			     nid, K(node_page_state(pgdat, NR_FILE_PMDMAPPED) *
+				    HPAGE_PMD_NR)
+#endif
+			    );
+	len += hugetlb_report_node_meminfo(buf, len, nid);
+	return len;
+}
+
+#undef K
+static DEVICE_ATTR(meminfo, 0444, node_read_meminfo, NULL);
+
+static ssize_t node_read_numastat(struct device *dev,
+				  struct device_attribute *attr, char *buf)
+{
+	return sysfs_emit(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, 0444, 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 len = 0;
+
+	for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
+		len += sysfs_emit_at(buf, len, "%s %lu\n",
+				     zone_stat_name(i),
+				     sum_zone_node_page_state(nid, i));
+
+#ifdef CONFIG_NUMA
+	for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++)
+		len += sysfs_emit_at(buf, len, "%s %lu\n",
+				     numa_stat_name(i),
+				     sum_zone_numa_state(nid, i));
+
+#endif
+	for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
+		len += sysfs_emit_at(buf, len, "%s %lu\n",
+				     node_stat_name(i),
+				     node_page_state_pages(pgdat, i));
+
+	return len;
+}
+static DEVICE_ATTR(vmstat, 0444, 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 += sysfs_emit_at(buf, len, "%s%d",
+				     i ? " " : "", node_distance(nid, i));
+	}
+
+	len += sysfs_emit_at(buf, len, "\n");
+	return len;
+}
+static DEVICE_ATTR(distance, 0444, 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 */
+	node_remove_accesses(node);
+	node_remove_caches(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));
+}
+
+/**
+ * register_memory_node_under_compute_node - link memory node to its compute
+ *					     node for a given access class.
+ * @mem_nid:	Memory node number
+ * @cpu_nid:	Cpu  node number
+ * @access:	Access class to register
+ *
+ * Description:
+ * 	For use with platforms that may have separate memory and compute nodes.
+ * 	This function will export node relationships linking which memory
+ * 	initiator nodes can access memory targets at a given ranked access
+ * 	class.
+ */
+int register_memory_node_under_compute_node(unsigned int mem_nid,
+					    unsigned int cpu_nid,
+					    unsigned access)
+{
+	struct node *init_node, *targ_node;
+	struct node_access_nodes *initiator, *target;
+	int ret;
+
+	if (!node_online(cpu_nid) || !node_online(mem_nid))
+		return -ENODEV;
+
+	init_node = node_devices[cpu_nid];
+	targ_node = node_devices[mem_nid];
+	initiator = node_init_node_access(init_node, access);
+	target = node_init_node_access(targ_node, access);
+	if (!initiator || !target)
+		return -ENOMEM;
+
+	ret = sysfs_add_link_to_group(&initiator->dev.kobj, "targets",
+				      &targ_node->dev.kobj,
+				      dev_name(&targ_node->dev));
+	if (ret)
+		return ret;
+
+	ret = sysfs_add_link_to_group(&target->dev.kobj, "initiators",
+				      &init_node->dev.kobj,
+				      dev_name(&init_node->dev));
+	if (ret)
+		goto err;
+
+	return 0;
+ err:
+	sysfs_remove_link_from_group(&initiator->dev.kobj, "targets",
+				     dev_name(&targ_node->dev));
+	return ret;
+}
+
+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 void 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 && ret != -EEXIST)
+		dev_err_ratelimited(&node_devices[nid]->dev,
+				    "can't create link to %s in sysfs (%d)\n",
+				    kobject_name(&mem_blk->dev.kobj), ret);
+
+	ret = sysfs_create_link_nowarn(&mem_blk->dev.kobj,
+				&node_devices[nid]->dev.kobj,
+				kobject_name(&node_devices[nid]->dev.kobj));
+	if (ret && ret != -EEXIST)
+		dev_err_ratelimited(&mem_blk->dev,
+				    "can't create link to %s in sysfs (%d)\n",
+				    kobject_name(&node_devices[nid]->dev.kobj),
+				    ret);
+}
+
+/* register memory section under specified node if it spans that node */
+static int register_mem_block_under_node_early(struct memory_block *mem_blk,
+					       void *arg)
+{
+	unsigned long memory_block_pfns = memory_block_size_bytes() / PAGE_SIZE;
+	unsigned long start_pfn = section_nr_to_pfn(mem_blk->start_section_nr);
+	unsigned long end_pfn = start_pfn + memory_block_pfns - 1;
+	int nid = *(int *)arg;
+	unsigned long pfn;
+
+	for (pfn = start_pfn; pfn <= end_pfn; pfn++) {
+		int page_nid;
+
+		/*
+		 * memory block could have several absent sections from start.
+		 * skip pfn range from absent section
+		 */
+		if (!pfn_in_present_section(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;
+
+		do_register_memory_block_under_node(nid, mem_blk);
+		return 0;
+	}
+	/* 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;
+
+	do_register_memory_block_under_node(nid, mem_blk);
+	return 0;
+}
+
+/*
+ * 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));
+}
+
+void 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;
+
+	walk_memory_blocks(PFN_PHYS(start_pfn), PFN_PHYS(end_pfn - start_pfn),
+			   (void *)&nid, func);
+	return;
+}
+
+#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);
+	}
+
+	INIT_LIST_HEAD(&node_devices[nid]->access_list);
+	/* initialize work queue for memory hot plug */
+	init_node_hugetlb_work(nid);
+	node_init_caches(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
+ */
+
+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 sysfs_emit(buf, "%*pbl\n",
+			  nodemask_pr_args(&node_states[na->state]));
+}
+
+#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),
+	[N_GENERIC_INITIATOR] = _NODE_ATTR(has_generic_initiator,
+					   N_GENERIC_INITIATOR),
+};
+
+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,
+	&node_state_attr[N_GENERIC_INITIATOR].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);