PM / Sleep: Add wakeup_source_activate and wakeup_source_deactivate tracepoints
[linux-2.6.git] / drivers / base / node.c
index c3bf051..90aa2a1 100644 (file)
 /*
- * drivers/base/node.c - basic Node class support
+ * Basic Node interface support
  */
 
-#include <linux/sysdev.h>
 #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 sysdev_class node_class = {
-       set_kset_name("node"),
+static struct bus_type node_subsys = {
+       .name = "node",
+       .dev_name = "node",
 };
 
 
-static ssize_t node_read_cpumap(struct sys_device * dev, char * buf)
+static ssize_t node_read_cpumap(struct device *dev, int type, char *buf)
 {
        struct node *node_dev = to_node(dev);
-       cpumask_t mask = node_to_cpumask(node_dev->sysdev.id);
+       const struct cpumask *mask = cpumask_of_node(node_dev->dev.id);
        int len;
 
-       /* 2004/06/03: buf currently PAGE_SIZE, need > 1 char per 4 bits. */
-       BUILD_BUG_ON(MAX_NUMNODES/4 > PAGE_SIZE/2);
+       /* 2008/04/07: buf currently PAGE_SIZE, need 9 chars per 32 bits. */
+       BUILD_BUG_ON((NR_CPUS/32 * 9) > (PAGE_SIZE-1));
 
-       len = cpumask_scnprintf(buf, PAGE_SIZE-1, mask);
-       len += sprintf(buf + len, "\n");
+       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 SYSDEV_ATTR(cpumap, S_IRUGO, node_read_cpumap, NULL);
+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 sys_device * dev, char * buf)
+static ssize_t node_read_meminfo(struct device *dev,
+                       struct device_attribute *attr, char *buf)
 {
        int n;
        int nid = dev->id;
        struct sysinfo i;
-       struct page_state ps;
-       unsigned long inactive;
-       unsigned long active;
-       unsigned long free;
 
        si_meminfo_node(&i, nid);
-       get_page_state_node(&ps, nid);
-       __get_zone_counts(&active, &inactive, &free, NODE_DATA(nid));
-
-       /* Check for negative values in these approximate counters */
-       if ((long)ps.nr_dirty < 0)
-               ps.nr_dirty = 0;
-       if ((long)ps.nr_writeback < 0)
-               ps.nr_writeback = 0;
-       if ((long)ps.nr_slab < 0)
-               ps.nr_slab = 0;
-
-       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 HighTotal:    %8lu kB\n"
-                      "Node %d HighFree:     %8lu kB\n"
-                      "Node %d LowTotal:     %8lu kB\n"
-                      "Node %d LowFree:      %8lu kB\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 Slab:         %8lu kB\n",
+       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(active),
-                      nid, K(inactive),
+                      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),
-                      nid, K(ps.nr_dirty),
-                      nid, K(ps.nr_writeback),
+                      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)),
-                      nid, K(ps.nr_slab));
+#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 SYSDEV_ATTR(meminfo, S_IRUGO, node_read_meminfo, NULL);
+static DEVICE_ATTR(meminfo, S_IRUGO, node_read_meminfo, NULL);
 
-static ssize_t node_read_numastat(struct sys_device * dev, char * buf)
+static ssize_t node_read_numastat(struct device *dev,
+                               struct device_attribute *attr, char *buf)
 {
-       unsigned long numa_hit, numa_miss, interleave_hit, numa_foreign;
-       unsigned long local_node, other_node;
-       int i, cpu;
-       pg_data_t *pg = NODE_DATA(dev->id);
-       numa_hit = 0;
-       numa_miss = 0;
-       interleave_hit = 0;
-       numa_foreign = 0;
-       local_node = 0;
-       other_node = 0;
-       for (i = 0; i < MAX_NR_ZONES; i++) {
-               struct zone *z = &pg->node_zones[i];
-               for_each_online_cpu(cpu) {
-                       struct per_cpu_pageset *ps = zone_pcp(z,cpu);
-                       numa_hit += ps->numa_hit;
-                       numa_miss += ps->numa_miss;
-                       numa_foreign += ps->numa_foreign;
-                       interleave_hit += ps->interleave_hit;
-                       local_node += ps->local_node;
-                       other_node += ps->other_node;
-               }
-       }
        return sprintf(buf,
                       "numa_hit %lu\n"
                       "numa_miss %lu\n"
@@ -126,23 +166,42 @@ static ssize_t node_read_numastat(struct sys_device * dev, char * buf)
                       "interleave_hit %lu\n"
                       "local_node %lu\n"
                       "other_node %lu\n",
-                      numa_hit,
-                      numa_miss,
-                      numa_foreign,
-                      interleave_hit,
-                      local_node,
-                      other_node);
+                      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 SYSDEV_ATTR(numastat, S_IRUGO, node_read_numastat, NULL);
+static DEVICE_ATTR(vmstat, S_IRUGO, node_read_vmstat, NULL);
 
-static ssize_t node_read_distance(struct sys_device * dev, char * buf)
+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 currently PAGE_SIZE, need ~4 chars per node */
-       BUILD_BUG_ON(MAX_NUMNODES*4 > PAGE_SIZE/2);
+       /*
+        * 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));
@@ -150,11 +209,52 @@ static ssize_t node_read_distance(struct sys_device * dev, char * buf)
        len += sprintf(buf + len, "\n");
        return len;
 }
-static SYSDEV_ATTR(distance, S_IRUGO, node_read_distance, NULL);
+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 driverfs device for a 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.
@@ -163,15 +263,23 @@ 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);
+       node->dev.id = num;
+       node->dev.bus = &node_subsys;
+       error = device_register(&node->dev);
 
        if (!error){
-               sysdev_create_file(&node->sysdev, &attr_cpumap);
-               sysdev_create_file(&node->sysdev, &attr_meminfo);
-               sysdev_create_file(&node->sysdev, &attr_numastat);
-               sysdev_create_file(&node->sysdev, &attr_distance);
+               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;
 }
@@ -185,12 +293,17 @@ int register_node(struct node *node, int num, struct node *parent)
  */
 void unregister_node(struct node *node)
 {
-       sysdev_remove_file(&node->sysdev, &attr_cpumap);
-       sysdev_remove_file(&node->sysdev, &attr_meminfo);
-       sysdev_remove_file(&node->sysdev, &attr_numastat);
-       sysdev_remove_file(&node->sysdev, &attr_distance);
+       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 */
 
-       sysdev_unregister(&node->sysdev);
+       device_unregister(&node->dev);
 }
 
 struct node node_devices[MAX_NUMNODES];
@@ -200,29 +313,241 @@ struct node node_devices[MAX_NUMNODES];
  */
 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));
-        }
+       int ret;
+       struct device *obj;
 
-       return 0;
+       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)
 {
-       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));
+       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;
@@ -242,6 +567,12 @@ int register_one_node(int nid)
                        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;
@@ -253,8 +584,85 @@ 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)
 {
-       return sysdev_class_register(&node_class);
+       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);