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

 /*
  * 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/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, int type, char *buf)
 {
 	struct node *node_dev = to_node(dev);
 	const struct cpumask *mask = cpumask_of_node(node_dev->dev.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 device *dev,
 				struct device_attribute *attr, char *buf)
 {
 	return node_read_cpumap(dev, 0, buf);
 }
 static inline ssize_t node_read_cpulist(struct device *dev,
 				struct device_attribute *attr, char *buf)
 {
 	return node_read_cpumap(dev, 1, 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 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(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
 	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"
 #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)),
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 		       nid, K(node_page_state(nid, NR_ANON_PAGES)
 			+ node_page_state(nid, NR_ANON_TRANSPARENT_HUGEPAGES) *
 			HPAGE_PMD_NR),
 #else
 		       nid, K(node_page_state(nid, NR_ANON_PAGES)),
 #endif
 		       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)),
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 		       nid, K(node_page_state(nid, NR_SLAB_UNRECLAIMABLE))
 			, nid,
 			K(node_page_state(nid, NR_ANON_TRANSPARENT_HUGEPAGES) *
 			HPAGE_PMD_NR));
 #else
 		       nid, K(node_page_state(nid, 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",
 		       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 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;
 	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],
 			     node_page_state(nid, 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);

 #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_HIGH_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


 /*
  * 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->dev.id = num;
 	node->dev.bus = &node_subsys;
 	error = device_register(&node->dev);

 	if (!error){
 		device_create_file(&node->dev, &dev_attr_cpumap);
 		device_create_file(&node->dev, &dev_attr_cpulist);
 		device_create_file(&node->dev, &dev_attr_meminfo);
 		device_create_file(&node->dev, &dev_attr_numastat);
 		device_create_file(&node->dev, &dev_attr_distance);
 		device_create_file(&node->dev, &dev_attr_vmstat);

 		scan_unevictable_register_node(node);

 		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)
 {
 	device_remove_file(&node->dev, &dev_attr_cpumap);
 	device_remove_file(&node->dev, &dev_attr_cpulist);
 	device_remove_file(&node->dev, &dev_attr_meminfo);
 	device_remove_file(&node->dev, &dev_attr_numastat);
 	device_remove_file(&node->dev, &dev_attr_distance);
 	device_remove_file(&node->dev, &dev_attr_vmstat);

 	scan_unevictable_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
 #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)
 {
 	int ret;
 	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->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;

 		page_nid = get_nid_for_pfn(pfn);
 		if (page_nid < 0)
 			continue;
 		if (page_nid != nid)
 			continue;
 		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));
 	}
 	/* 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,
 				    unsigned long phys_index)
 {
 	NODEMASK_ALLOC(nodemask_t, unlinked_nodes, GFP_KERNEL);
 	unsigned long pfn, sect_start_pfn, sect_end_pfn;

 	if (!mem_blk) {
 		NODEMASK_FREE(unlinked_nodes);
 		return -EFAULT;
 	}
 	if (!unlinked_nodes)
 		return -ENOMEM;
 	nodes_clear(*unlinked_nodes);

 	sect_start_pfn = section_nr_to_pfn(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].dev.kobj,
 			 kobject_name(&mem_blk->dev.kobj));
 		sysfs_remove_link(&mem_blk->dev.kobj,
 			 kobject_name(&node_devices[nid].dev.kobj));
 	}
 	NODEMASK_FREE(unlinked_nodes);
 	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;
 	struct memory_block *mem_blk = NULL;
 	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;
 		int ret;

 		if (!present_section_nr(section_nr))
 			continue;
 		mem_sect = __nr_to_section(section_nr);

 		/* same memblock ? */
 		if (mem_blk)
 			if ((section_nr >= mem_blk->start_section_nr) &&
 			    (section_nr <= mem_blk->end_section_nr))
 				continue;

 		mem_blk = find_memory_block_hinted(mem_sect, mem_blk);

 		ret = register_mem_sect_under_node(mem_blk, nid);
 		if (!err)
 			err = ret;

 		/* discard ref obtained in find_memory_block() */
 	}

 	if (mem_blk)
 		kobject_put(&mem_blk->dev.kobj);
 	return err;
 }

 #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 */
 #else	/* !CONFIG_MEMORY_HOTPLUG_SPARSE */

 static int link_mem_sections(int nid) { return 0; }
 #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 = 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);

 		/* initialize work queue for memory hot plug */
 		init_node_hugetlb_work(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;
 }

 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[] = {
 	_NODE_ATTR(possible, N_POSSIBLE),
 	_NODE_ATTR(online, N_ONLINE),
 	_NODE_ATTR(has_normal_memory, N_NORMAL_MEMORY),
 	_NODE_ATTR(has_cpu, N_CPU),
 #ifdef CONFIG_HIGHMEM
 	_NODE_ATTR(has_high_memory, N_HIGH_MEMORY),
 #endif
 };

 static struct attribute *node_state_attrs[] = {
 	&node_state_attr[0].attr.attr,
 	&node_state_attr[1].attr.attr,
 	&node_state_attr[2].attr.attr,
 	&node_state_attr[3].attr.attr,
 #ifdef CONFIG_HIGHMEM
 	&node_state_attr[4].attr.attr,
 #endif
 	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) {
 		hotplug_memory_notifier(node_memory_callback,
 					NODE_CALLBACK_PRI);
 	}

 	/*
 	 * 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);
	/*
	* 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/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, int type, char buf)
	{
	struct node *node_dev = to_node(dev);
	const struct cpumask *mask = cpumask_of_node(node_dev->dev.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 device *dev,
	struct device_attribute attr, char buf)
	{
	return node_read_cpumap(dev, 0, buf);
	}
	static inline ssize_t node_read_cpulist(struct device *dev,
	struct device_attribute attr, char buf)
	{
	return node_read_cpumap(dev, 1, 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 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(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
	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"
	#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)),
	#ifdef CONFIG_TRANSPARENT_HUGEPAGE
	nid, K(node_page_state(nid, NR_ANON_PAGES)
	+ node_page_state(nid, NR_ANON_TRANSPARENT_HUGEPAGES) *
	HPAGE_PMD_NR),
	#else
	nid, K(node_page_state(nid, NR_ANON_PAGES)),
	#endif
	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)),
	#ifdef CONFIG_TRANSPARENT_HUGEPAGE
	nid, K(node_page_state(nid, NR_SLAB_UNRECLAIMABLE))
	, nid,
	K(node_page_state(nid, NR_ANON_TRANSPARENT_HUGEPAGES) *
	HPAGE_PMD_NR));
	#else
	nid, K(node_page_state(nid, 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",
	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 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;
	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],
	node_page_state(nid, 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);

	#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_HIGH_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


	/*
	* 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->dev.id = num;
	node->dev.bus = &node_subsys;
	error = device_register(&node->dev);

	if (!error){
	device_create_file(&node->dev, &dev_attr_cpumap);
	device_create_file(&node->dev, &dev_attr_cpulist);
	device_create_file(&node->dev, &dev_attr_meminfo);
	device_create_file(&node->dev, &dev_attr_numastat);
	device_create_file(&node->dev, &dev_attr_distance);
	device_create_file(&node->dev, &dev_attr_vmstat);

	scan_unevictable_register_node(node);

	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)
	{
	device_remove_file(&node->dev, &dev_attr_cpumap);
	device_remove_file(&node->dev, &dev_attr_cpulist);
	device_remove_file(&node->dev, &dev_attr_meminfo);
	device_remove_file(&node->dev, &dev_attr_numastat);
	device_remove_file(&node->dev, &dev_attr_distance);
	device_remove_file(&node->dev, &dev_attr_vmstat);

	scan_unevictable_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
	#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)
	{
	int ret;
	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->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;

	page_nid = get_nid_for_pfn(pfn);
	if (page_nid < 0)
	continue;
	if (page_nid != nid)
	continue;
	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));
	}
	/* 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,
	unsigned long phys_index)
	{
	NODEMASK_ALLOC(nodemask_t, unlinked_nodes, GFP_KERNEL);
	unsigned long pfn, sect_start_pfn, sect_end_pfn;

	if (!mem_blk) {
	NODEMASK_FREE(unlinked_nodes);
	return -EFAULT;
	}
	if (!unlinked_nodes)
	return -ENOMEM;
	nodes_clear(*unlinked_nodes);

	sect_start_pfn = section_nr_to_pfn(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].dev.kobj,
	kobject_name(&mem_blk->dev.kobj));
	sysfs_remove_link(&mem_blk->dev.kobj,
	kobject_name(&node_devices[nid].dev.kobj));
	}
	NODEMASK_FREE(unlinked_nodes);
	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;
	struct memory_block *mem_blk = NULL;
	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;
	int ret;

	if (!present_section_nr(section_nr))
	continue;
	mem_sect = __nr_to_section(section_nr);

	/* same memblock ? */
	if (mem_blk)
	if ((section_nr >= mem_blk->start_section_nr) &&
	(section_nr <= mem_blk->end_section_nr))
	continue;

	mem_blk = find_memory_block_hinted(mem_sect, mem_blk);

	ret = register_mem_sect_under_node(mem_blk, nid);
	if (!err)
	err = ret;

	/* discard ref obtained in find_memory_block() */
	}

	if (mem_blk)
	kobject_put(&mem_blk->dev.kobj);
	return err;
	}

	#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 */
	#else /* !CONFIG_MEMORY_HOTPLUG_SPARSE */

	static int link_mem_sections(int nid) { return 0; }
	#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 = 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);

	/* initialize work queue for memory hot plug */
	init_node_hugetlb_work(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;
	}

	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[] = {
	_NODE_ATTR(possible, N_POSSIBLE),
	_NODE_ATTR(online, N_ONLINE),
	_NODE_ATTR(has_normal_memory, N_NORMAL_MEMORY),
	_NODE_ATTR(has_cpu, N_CPU),
	#ifdef CONFIG_HIGHMEM
	_NODE_ATTR(has_high_memory, N_HIGH_MEMORY),
	#endif
	};

	static struct attribute *node_state_attrs[] = {
	&node_state_attr[0].attr.attr,
	&node_state_attr[1].attr.attr,
	&node_state_attr[2].attr.attr,
	&node_state_attr[3].attr.attr,
	#ifdef CONFIG_HIGHMEM
	&node_state_attr[4].attr.attr,
	#endif
	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) {
	hotplug_memory_notifier(node_memory_callback,
	NODE_CALLBACK_PRI);
	}

	/*
	* 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);