drivers/base/node.c - kernel/msm-4.9 - Gitiles

 /*
  * drivers/base/node.c - basic Node class support
  */

 #include <linux/sysdev.h>
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/mm.h>
 #include <linux/memory.h>
 #include <linux/node.h>
 #include <linux/hugetlb.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>

 static struct sysdev_class node_class = {
 	.name = "node",
 };


 static ssize_t node_read_cpumap(struct sys_device *dev, int type, char *buf)
 {
 	struct node *node_dev = to_node(dev);
 	const struct cpumask *mask = cpumask_of_node(node_dev->sysdev.id);
 	int len;

 	/* 2008/04/07: buf currently PAGE_SIZE, need 9 chars per 32 bits. */
 	BUILD_BUG_ON((NR_CPUS/32 * 9) > (PAGE_SIZE-1));

 	len = type?
 		cpulist_scnprintf(buf, PAGE_SIZE-2, mask) :
 		cpumask_scnprintf(buf, PAGE_SIZE-2, mask);
  	buf[len++] = '\n';
  	buf[len] = '\0';
 	return len;
 }

 static inline ssize_t node_read_cpumask(struct sys_device *dev,
 				struct sysdev_attribute *attr, char *buf)
 {
 	return node_read_cpumap(dev, 0, buf);
 }
 static inline ssize_t node_read_cpulist(struct sys_device *dev,
 				struct sysdev_attribute *attr, char *buf)
 {
 	return node_read_cpumap(dev, 1, buf);
 }

 static SYSDEV_ATTR(cpumap,  S_IRUGO, node_read_cpumask, NULL);
 static SYSDEV_ATTR(cpulist, S_IRUGO, node_read_cpulist, NULL);

 #define K(x) ((x) << (PAGE_SHIFT - 10))
 static ssize_t node_read_meminfo(struct sys_device * dev,
 			struct sysdev_attribute *attr, char * buf)
 {
 	int n;
 	int nid = dev->id;
 	struct sysinfo i;

 	si_meminfo_node(&i, nid);

 	n = sprintf(buf, "\n"
 		       "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"
 #ifdef CONFIG_HIGHMEM
 		       "Node %d HighTotal:      %8lu kB\n"
 		       "Node %d HighFree:       %8lu kB\n"
 		       "Node %d LowTotal:       %8lu kB\n"
 		       "Node %d LowFree:        %8lu kB\n"
 #endif
 		       "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",
 		       nid, K(i.totalram),
 		       nid, K(i.freeram),
 		       nid, K(i.totalram - i.freeram),
 		       nid, K(node_page_state(nid, NR_ACTIVE_ANON) +
 				node_page_state(nid, NR_ACTIVE_FILE)),
 		       nid, K(node_page_state(nid, NR_INACTIVE_ANON) +
 				node_page_state(nid, NR_INACTIVE_FILE)),
 		       nid, K(node_page_state(nid, NR_ACTIVE_ANON)),
 		       nid, K(node_page_state(nid, NR_INACTIVE_ANON)),
 		       nid, K(node_page_state(nid, NR_ACTIVE_FILE)),
 		       nid, K(node_page_state(nid, NR_INACTIVE_FILE)),
 		       nid, K(node_page_state(nid, NR_UNEVICTABLE)),
 		       nid, K(node_page_state(nid, NR_MLOCK)),
 #ifdef CONFIG_HIGHMEM
 		       nid, K(i.totalhigh),
 		       nid, K(i.freehigh),
 		       nid, K(i.totalram - i.totalhigh),
 		       nid, K(i.freeram - i.freehigh),
 #endif
 		       nid, K(node_page_state(nid, NR_FILE_DIRTY)),
 		       nid, K(node_page_state(nid, NR_WRITEBACK)),
 		       nid, K(node_page_state(nid, NR_FILE_PAGES)),
 		       nid, K(node_page_state(nid, NR_FILE_MAPPED)),
 		       nid, K(node_page_state(nid, NR_ANON_PAGES)),
 		       nid, K(node_page_state(nid, NR_SHMEM)),
 		       nid, node_page_state(nid, NR_KERNEL_STACK) *
 				THREAD_SIZE / 1024,
 		       nid, K(node_page_state(nid, NR_PAGETABLE)),
 		       nid, K(node_page_state(nid, NR_UNSTABLE_NFS)),
 		       nid, K(node_page_state(nid, NR_BOUNCE)),
 		       nid, K(node_page_state(nid, NR_WRITEBACK_TEMP)),
 		       nid, K(node_page_state(nid, NR_SLAB_RECLAIMABLE) +
 				node_page_state(nid, NR_SLAB_UNRECLAIMABLE)),
 		       nid, K(node_page_state(nid, NR_SLAB_RECLAIMABLE)),
 		       nid, K(node_page_state(nid, NR_SLAB_UNRECLAIMABLE)));
 	n += hugetlb_report_node_meminfo(nid, buf + n);
 	return n;
 }

 #undef K
 static SYSDEV_ATTR(meminfo, S_IRUGO, node_read_meminfo, NULL);

 static ssize_t node_read_numastat(struct sys_device * dev,
 				struct sysdev_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",
 		       node_page_state(dev->id, NUMA_HIT),
 		       node_page_state(dev->id, NUMA_MISS),
 		       node_page_state(dev->id, NUMA_FOREIGN),
 		       node_page_state(dev->id, NUMA_INTERLEAVE_HIT),
 		       node_page_state(dev->id, NUMA_LOCAL),
 		       node_page_state(dev->id, NUMA_OTHER));
 }
 static SYSDEV_ATTR(numastat, S_IRUGO, node_read_numastat, NULL);

 static ssize_t node_read_distance(struct sys_device * dev,
 			struct sysdev_attribute *attr, char * buf)
 {
 	int nid = dev->id;
 	int len = 0;
 	int i;

 	/* buf currently PAGE_SIZE, need ~4 chars per node */
 	BUILD_BUG_ON(MAX_NUMNODES*4 > PAGE_SIZE/2);

 	for_each_online_node(i)
 		len += sprintf(buf + len, "%s%d", i ? " " : "", node_distance(nid, i));

 	len += sprintf(buf + len, "\n");
 	return len;
 }
 static SYSDEV_ATTR(distance, S_IRUGO, node_read_distance, NULL);


 /*
  * register_node - Setup a sysfs device for a node.
  * @num - Node number to use when creating the device.
  *
  * Initialize and register the node device.
  */
 int register_node(struct node *node, int num, struct node *parent)
 {
 	int error;

 	node->sysdev.id = num;
 	node->sysdev.cls = &node_class;
 	error = sysdev_register(&node->sysdev);

 	if (!error){
 		sysdev_create_file(&node->sysdev, &attr_cpumap);
 		sysdev_create_file(&node->sysdev, &attr_cpulist);
 		sysdev_create_file(&node->sysdev, &attr_meminfo);
 		sysdev_create_file(&node->sysdev, &attr_numastat);
 		sysdev_create_file(&node->sysdev, &attr_distance);

 		scan_unevictable_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)
 {
 	sysdev_remove_file(&node->sysdev, &attr_cpumap);
 	sysdev_remove_file(&node->sysdev, &attr_cpulist);
 	sysdev_remove_file(&node->sysdev, &attr_meminfo);
 	sysdev_remove_file(&node->sysdev, &attr_numastat);
 	sysdev_remove_file(&node->sysdev, &attr_distance);

 	scan_unevictable_unregister_node(node);

 	sysdev_unregister(&node->sysdev);
 }

 struct node node_devices[MAX_NUMNODES];

 /*
  * register cpu under node
  */
 int register_cpu_under_node(unsigned int cpu, unsigned int nid)
 {
 	if (node_online(nid)) {
 		struct sys_device *obj = get_cpu_sysdev(cpu);
 		if (!obj)
 			return 0;
 		return sysfs_create_link(&node_devices[nid].sysdev.kobj,
 					 &obj->kobj,
 					 kobject_name(&obj->kobj));
 	 }

 	return 0;
 }

 int unregister_cpu_under_node(unsigned int cpu, unsigned int nid)
 {
 	if (node_online(nid)) {
 		struct sys_device *obj = get_cpu_sysdev(cpu);
 		if (obj)
 			sysfs_remove_link(&node_devices[nid].sysdev.kobj,
 					 kobject_name(&obj->kobj));
 	}
 	return 0;
 }

 #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
 #define page_initialized(page)  (page->lru.next)

 static int get_nid_for_pfn(unsigned long pfn)
 {
 	struct page *page;

 	if (!pfn_valid_within(pfn))
 		return -1;
 	page = pfn_to_page(pfn);
 	if (!page_initialized(page))
 		return -1;
 	return pfn_to_nid(pfn);
 }

 /* register memory section under specified node if it spans that node */
 int register_mem_sect_under_node(struct memory_block *mem_blk, int nid)
 {
 	unsigned long pfn, sect_start_pfn, sect_end_pfn;

 	if (!mem_blk)
 		return -EFAULT;
 	if (!node_online(nid))
 		return 0;
 	sect_start_pfn = section_nr_to_pfn(mem_blk->phys_index);
 	sect_end_pfn = sect_start_pfn + PAGES_PER_SECTION - 1;
 	for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
 		int page_nid;

 		page_nid = get_nid_for_pfn(pfn);
 		if (page_nid < 0)
 			continue;
 		if (page_nid != nid)
 			continue;
 		return sysfs_create_link_nowarn(&node_devices[nid].sysdev.kobj,
 					&mem_blk->sysdev.kobj,
 					kobject_name(&mem_blk->sysdev.kobj));
 	}
 	/* mem section does not span the specified node */
 	return 0;
 }

 /* unregister memory section under all nodes that it spans */
 int unregister_mem_sect_under_nodes(struct memory_block *mem_blk)
 {
 	nodemask_t unlinked_nodes;
 	unsigned long pfn, sect_start_pfn, sect_end_pfn;

 	if (!mem_blk)
 		return -EFAULT;
 	nodes_clear(unlinked_nodes);
 	sect_start_pfn = section_nr_to_pfn(mem_blk->phys_index);
 	sect_end_pfn = sect_start_pfn + PAGES_PER_SECTION - 1;
 	for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
 		int nid;

 		nid = get_nid_for_pfn(pfn);
 		if (nid < 0)
 			continue;
 		if (!node_online(nid))
 			continue;
 		if (node_test_and_set(nid, unlinked_nodes))
 			continue;
 		sysfs_remove_link(&node_devices[nid].sysdev.kobj,
 			 kobject_name(&mem_blk->sysdev.kobj));
 	}
 	return 0;
 }

 static int link_mem_sections(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;
 	int err = 0;

 	for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
 		unsigned long section_nr = pfn_to_section_nr(pfn);
 		struct mem_section *mem_sect;
 		struct memory_block *mem_blk;
 		int ret;

 		if (!present_section_nr(section_nr))
 			continue;
 		mem_sect = __nr_to_section(section_nr);
 		mem_blk = find_memory_block(mem_sect);
 		ret = register_mem_sect_under_node(mem_blk, nid);
 		if (!err)
 			err = ret;

 		/* discard ref obtained in find_memory_block() */
 		kobject_put(&mem_blk->sysdev.kobj);
 	}
 	return err;
 }
 #else
 static int link_mem_sections(int nid) { return 0; }
 #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */

 int register_one_node(int nid)
 {
 	int error = 0;
 	int cpu;

 	if (node_online(nid)) {
 		int p_node = parent_node(nid);
 		struct node *parent = NULL;

 		if (p_node != nid)
 			parent = &node_devices[p_node];

 		error = register_node(&node_devices[nid], nid, parent);

 		/* link cpu under this node */
 		for_each_present_cpu(cpu) {
 			if (cpu_to_node(cpu) == nid)
 				register_cpu_under_node(cpu, nid);
 		}

 		/* link memory sections under this node */
 		error = link_mem_sections(nid);
 	}

 	return error;

 }

 void unregister_one_node(int nid)
 {
 	unregister_node(&node_devices[nid]);
 }

 /*
  * node states attributes
  */

 static ssize_t print_nodes_state(enum node_states state, char *buf)
 {
 	int n;

 	n = nodelist_scnprintf(buf, PAGE_SIZE, node_states[state]);
 	if (n > 0 && PAGE_SIZE > n + 1) {
 		*(buf + n++) = '\n';
 		*(buf + n++) = '\0';
 	}
 	return n;
 }

 static ssize_t print_nodes_possible(struct sysdev_class *class, char *buf)
 {
 	return print_nodes_state(N_POSSIBLE, buf);
 }

 static ssize_t print_nodes_online(struct sysdev_class *class, char *buf)
 {
 	return print_nodes_state(N_ONLINE, buf);
 }

 static ssize_t print_nodes_has_normal_memory(struct sysdev_class *class,
 						char *buf)
 {
 	return print_nodes_state(N_NORMAL_MEMORY, buf);
 }

 static ssize_t print_nodes_has_cpu(struct sysdev_class *class, char *buf)
 {
 	return print_nodes_state(N_CPU, buf);
 }

 static SYSDEV_CLASS_ATTR(possible, 0444, print_nodes_possible, NULL);
 static SYSDEV_CLASS_ATTR(online, 0444, print_nodes_online, NULL);
 static SYSDEV_CLASS_ATTR(has_normal_memory, 0444, print_nodes_has_normal_memory,
 									NULL);
 static SYSDEV_CLASS_ATTR(has_cpu, 0444, print_nodes_has_cpu, NULL);

 #ifdef CONFIG_HIGHMEM
 static ssize_t print_nodes_has_high_memory(struct sysdev_class *class,
 						 char *buf)
 {
 	return print_nodes_state(N_HIGH_MEMORY, buf);
 }

 static SYSDEV_CLASS_ATTR(has_high_memory, 0444, print_nodes_has_high_memory,
 									 NULL);
 #endif

 struct sysdev_class_attribute *node_state_attr[] = {
 	&attr_possible,
 	&attr_online,
 	&attr_has_normal_memory,
 #ifdef CONFIG_HIGHMEM
 	&attr_has_high_memory,
 #endif
 	&attr_has_cpu,
 };

 static int node_states_init(void)
 {
 	int i;
 	int err = 0;

 	for (i = 0;  i < NR_NODE_STATES; i++) {
 		int ret;
 		ret = sysdev_class_create_file(&node_class, node_state_attr[i]);
 		if (!err)
 			err = ret;
 	}
 	return err;
 }

 static int __init register_node_type(void)
 {
 	int ret;

 	ret = sysdev_class_register(&node_class);
 	if (!ret)
 		ret = node_states_init();

 	/*
 	 * 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);
	/*
	* drivers/base/node.c - basic Node class support
	*/

	#include <linux/sysdev.h>
	#include <linux/module.h>
	#include <linux/init.h>
	#include <linux/mm.h>
	#include <linux/memory.h>
	#include <linux/node.h>
	#include <linux/hugetlb.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>

	static struct sysdev_class node_class = {
	.name = "node",
	};


	static ssize_t node_read_cpumap(struct sys_device dev, int type, char buf)
	{
	struct node *node_dev = to_node(dev);
	const struct cpumask *mask = cpumask_of_node(node_dev->sysdev.id);
	int len;

	/* 2008/04/07: buf currently PAGE_SIZE, need 9 chars per 32 bits. */
	BUILD_BUG_ON((NR_CPUS/32 * 9) > (PAGE_SIZE-1));

	len = type?
	cpulist_scnprintf(buf, PAGE_SIZE-2, mask) :
	cpumask_scnprintf(buf, PAGE_SIZE-2, mask);
	buf[len++] = '\n';
	buf[len] = '\0';
	return len;
	}

	static inline ssize_t node_read_cpumask(struct sys_device *dev,
	struct sysdev_attribute attr, char buf)
	{
	return node_read_cpumap(dev, 0, buf);
	}
	static inline ssize_t node_read_cpulist(struct sys_device *dev,
	struct sysdev_attribute attr, char buf)
	{
	return node_read_cpumap(dev, 1, buf);
	}

	static SYSDEV_ATTR(cpumap, S_IRUGO, node_read_cpumask, NULL);
	static SYSDEV_ATTR(cpulist, S_IRUGO, node_read_cpulist, NULL);

	#define K(x) ((x) << (PAGE_SHIFT - 10))
	static ssize_t node_read_meminfo(struct sys_device * dev,
	struct sysdev_attribute attr, char buf)
	{
	int n;
	int nid = dev->id;
	struct sysinfo i;

	si_meminfo_node(&i, nid);

	n = sprintf(buf, "\n"
	"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"
	#ifdef CONFIG_HIGHMEM
	"Node %d HighTotal: %8lu kB\n"
	"Node %d HighFree: %8lu kB\n"
	"Node %d LowTotal: %8lu kB\n"
	"Node %d LowFree: %8lu kB\n"
	#endif
	"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",
	nid, K(i.totalram),
	nid, K(i.freeram),
	nid, K(i.totalram - i.freeram),
	nid, K(node_page_state(nid, NR_ACTIVE_ANON) +
	node_page_state(nid, NR_ACTIVE_FILE)),
	nid, K(node_page_state(nid, NR_INACTIVE_ANON) +
	node_page_state(nid, NR_INACTIVE_FILE)),
	nid, K(node_page_state(nid, NR_ACTIVE_ANON)),
	nid, K(node_page_state(nid, NR_INACTIVE_ANON)),
	nid, K(node_page_state(nid, NR_ACTIVE_FILE)),
	nid, K(node_page_state(nid, NR_INACTIVE_FILE)),
	nid, K(node_page_state(nid, NR_UNEVICTABLE)),
	nid, K(node_page_state(nid, NR_MLOCK)),
	#ifdef CONFIG_HIGHMEM
	nid, K(i.totalhigh),
	nid, K(i.freehigh),
	nid, K(i.totalram - i.totalhigh),
	nid, K(i.freeram - i.freehigh),
	#endif
	nid, K(node_page_state(nid, NR_FILE_DIRTY)),
	nid, K(node_page_state(nid, NR_WRITEBACK)),
	nid, K(node_page_state(nid, NR_FILE_PAGES)),
	nid, K(node_page_state(nid, NR_FILE_MAPPED)),
	nid, K(node_page_state(nid, NR_ANON_PAGES)),
	nid, K(node_page_state(nid, NR_SHMEM)),
	nid, node_page_state(nid, NR_KERNEL_STACK) *
	THREAD_SIZE / 1024,
	nid, K(node_page_state(nid, NR_PAGETABLE)),
	nid, K(node_page_state(nid, NR_UNSTABLE_NFS)),
	nid, K(node_page_state(nid, NR_BOUNCE)),
	nid, K(node_page_state(nid, NR_WRITEBACK_TEMP)),
	nid, K(node_page_state(nid, NR_SLAB_RECLAIMABLE) +
	node_page_state(nid, NR_SLAB_UNRECLAIMABLE)),
	nid, K(node_page_state(nid, NR_SLAB_RECLAIMABLE)),
	nid, K(node_page_state(nid, NR_SLAB_UNRECLAIMABLE)));
	n += hugetlb_report_node_meminfo(nid, buf + n);
	return n;
	}

	#undef K
	static SYSDEV_ATTR(meminfo, S_IRUGO, node_read_meminfo, NULL);

	static ssize_t node_read_numastat(struct sys_device * dev,
	struct sysdev_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",
	node_page_state(dev->id, NUMA_HIT),
	node_page_state(dev->id, NUMA_MISS),
	node_page_state(dev->id, NUMA_FOREIGN),
	node_page_state(dev->id, NUMA_INTERLEAVE_HIT),
	node_page_state(dev->id, NUMA_LOCAL),
	node_page_state(dev->id, NUMA_OTHER));
	}
	static SYSDEV_ATTR(numastat, S_IRUGO, node_read_numastat, NULL);

	static ssize_t node_read_distance(struct sys_device * dev,
	struct sysdev_attribute attr, char buf)
	{
	int nid = dev->id;
	int len = 0;
	int i;

	/* buf currently PAGE_SIZE, need ~4 chars per node */
	BUILD_BUG_ON(MAX_NUMNODES*4 > PAGE_SIZE/2);

	for_each_online_node(i)
	len += sprintf(buf + len, "%s%d", i ? " " : "", node_distance(nid, i));

	len += sprintf(buf + len, "\n");
	return len;
	}
	static SYSDEV_ATTR(distance, S_IRUGO, node_read_distance, NULL);


	/*
	* register_node - Setup a sysfs device for a node.
	* @num - Node number to use when creating the device.
	*
	* Initialize and register the node device.
	*/
	int register_node(struct node node, int num, struct node parent)
	{
	int error;

	node->sysdev.id = num;
	node->sysdev.cls = &node_class;
	error = sysdev_register(&node->sysdev);

	if (!error){
	sysdev_create_file(&node->sysdev, &attr_cpumap);
	sysdev_create_file(&node->sysdev, &attr_cpulist);
	sysdev_create_file(&node->sysdev, &attr_meminfo);
	sysdev_create_file(&node->sysdev, &attr_numastat);
	sysdev_create_file(&node->sysdev, &attr_distance);

	scan_unevictable_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)
	{
	sysdev_remove_file(&node->sysdev, &attr_cpumap);
	sysdev_remove_file(&node->sysdev, &attr_cpulist);
	sysdev_remove_file(&node->sysdev, &attr_meminfo);
	sysdev_remove_file(&node->sysdev, &attr_numastat);
	sysdev_remove_file(&node->sysdev, &attr_distance);

	scan_unevictable_unregister_node(node);

	sysdev_unregister(&node->sysdev);
	}

	struct node node_devices[MAX_NUMNODES];

	/*
	* register cpu under node
	*/
	int register_cpu_under_node(unsigned int cpu, unsigned int nid)
	{
	if (node_online(nid)) {
	struct sys_device *obj = get_cpu_sysdev(cpu);
	if (!obj)
	return 0;
	return sysfs_create_link(&node_devices[nid].sysdev.kobj,
	&obj->kobj,
	kobject_name(&obj->kobj));
	}

	return 0;
	}

	int unregister_cpu_under_node(unsigned int cpu, unsigned int nid)
	{
	if (node_online(nid)) {
	struct sys_device *obj = get_cpu_sysdev(cpu);
	if (obj)
	sysfs_remove_link(&node_devices[nid].sysdev.kobj,
	kobject_name(&obj->kobj));
	}
	return 0;
	}

	#ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
	#define page_initialized(page) (page->lru.next)

	static int get_nid_for_pfn(unsigned long pfn)
	{
	struct page *page;

	if (!pfn_valid_within(pfn))
	return -1;
	page = pfn_to_page(pfn);
	if (!page_initialized(page))
	return -1;
	return pfn_to_nid(pfn);
	}

	/* register memory section under specified node if it spans that node */
	int register_mem_sect_under_node(struct memory_block *mem_blk, int nid)
	{
	unsigned long pfn, sect_start_pfn, sect_end_pfn;

	if (!mem_blk)
	return -EFAULT;
	if (!node_online(nid))
	return 0;
	sect_start_pfn = section_nr_to_pfn(mem_blk->phys_index);
	sect_end_pfn = sect_start_pfn + PAGES_PER_SECTION - 1;
	for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
	int page_nid;

	page_nid = get_nid_for_pfn(pfn);
	if (page_nid < 0)
	continue;
	if (page_nid != nid)
	continue;
	return sysfs_create_link_nowarn(&node_devices[nid].sysdev.kobj,
	&mem_blk->sysdev.kobj,
	kobject_name(&mem_blk->sysdev.kobj));
	}
	/* mem section does not span the specified node */
	return 0;
	}

	/* unregister memory section under all nodes that it spans */
	int unregister_mem_sect_under_nodes(struct memory_block *mem_blk)
	{
	nodemask_t unlinked_nodes;
	unsigned long pfn, sect_start_pfn, sect_end_pfn;

	if (!mem_blk)
	return -EFAULT;
	nodes_clear(unlinked_nodes);
	sect_start_pfn = section_nr_to_pfn(mem_blk->phys_index);
	sect_end_pfn = sect_start_pfn + PAGES_PER_SECTION - 1;
	for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
	int nid;

	nid = get_nid_for_pfn(pfn);
	if (nid < 0)
	continue;
	if (!node_online(nid))
	continue;
	if (node_test_and_set(nid, unlinked_nodes))
	continue;
	sysfs_remove_link(&node_devices[nid].sysdev.kobj,
	kobject_name(&mem_blk->sysdev.kobj));
	}
	return 0;
	}

	static int link_mem_sections(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;
	int err = 0;

	for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
	unsigned long section_nr = pfn_to_section_nr(pfn);
	struct mem_section *mem_sect;
	struct memory_block *mem_blk;
	int ret;

	if (!present_section_nr(section_nr))
	continue;
	mem_sect = __nr_to_section(section_nr);
	mem_blk = find_memory_block(mem_sect);
	ret = register_mem_sect_under_node(mem_blk, nid);
	if (!err)
	err = ret;

	/* discard ref obtained in find_memory_block() */
	kobject_put(&mem_blk->sysdev.kobj);
	}
	return err;
	}
	#else
	static int link_mem_sections(int nid) { return 0; }
	#endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */

	int register_one_node(int nid)
	{
	int error = 0;
	int cpu;

	if (node_online(nid)) {
	int p_node = parent_node(nid);
	struct node *parent = NULL;

	if (p_node != nid)
	parent = &node_devices[p_node];

	error = register_node(&node_devices[nid], nid, parent);

	/* link cpu under this node */
	for_each_present_cpu(cpu) {
	if (cpu_to_node(cpu) == nid)
	register_cpu_under_node(cpu, nid);
	}

	/* link memory sections under this node */
	error = link_mem_sections(nid);
	}

	return error;

	}

	void unregister_one_node(int nid)
	{
	unregister_node(&node_devices[nid]);
	}

	/*
	* node states attributes
	*/

	static ssize_t print_nodes_state(enum node_states state, char *buf)
	{
	int n;

	n = nodelist_scnprintf(buf, PAGE_SIZE, node_states[state]);
	if (n > 0 && PAGE_SIZE > n + 1) {
	*(buf + n++) = '\n';
	*(buf + n++) = '\0';
	}
	return n;
	}

	static ssize_t print_nodes_possible(struct sysdev_class class, char buf)
	{
	return print_nodes_state(N_POSSIBLE, buf);
	}

	static ssize_t print_nodes_online(struct sysdev_class class, char buf)
	{
	return print_nodes_state(N_ONLINE, buf);
	}

	static ssize_t print_nodes_has_normal_memory(struct sysdev_class *class,
	char *buf)
	{
	return print_nodes_state(N_NORMAL_MEMORY, buf);
	}

	static ssize_t print_nodes_has_cpu(struct sysdev_class class, char buf)
	{
	return print_nodes_state(N_CPU, buf);
	}

	static SYSDEV_CLASS_ATTR(possible, 0444, print_nodes_possible, NULL);
	static SYSDEV_CLASS_ATTR(online, 0444, print_nodes_online, NULL);
	static SYSDEV_CLASS_ATTR(has_normal_memory, 0444, print_nodes_has_normal_memory,
	NULL);
	static SYSDEV_CLASS_ATTR(has_cpu, 0444, print_nodes_has_cpu, NULL);

	#ifdef CONFIG_HIGHMEM
	static ssize_t print_nodes_has_high_memory(struct sysdev_class *class,
	char *buf)
	{
	return print_nodes_state(N_HIGH_MEMORY, buf);
	}

	static SYSDEV_CLASS_ATTR(has_high_memory, 0444, print_nodes_has_high_memory,
	NULL);
	#endif

	struct sysdev_class_attribute *node_state_attr[] = {
	&attr_possible,
	&attr_online,
	&attr_has_normal_memory,
	#ifdef CONFIG_HIGHMEM
	&attr_has_high_memory,
	#endif
	&attr_has_cpu,
	};

	static int node_states_init(void)
	{
	int i;
	int err = 0;

	for (i = 0; i < NR_NODE_STATES; i++) {
	int ret;
	ret = sysdev_class_create_file(&node_class, node_state_attr[i]);
	if (!err)
	err = ret;
	}
	return err;
	}

	static int __init register_node_type(void)
	{
	int ret;

	ret = sysdev_class_register(&node_class);
	if (!ret)
	ret = node_states_init();

	/*
	* 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);