drivers/base/node.c

   1 /*
   2  * Basic Node interface support
   3  */
   4
   5 #include <linux/module.h>
   6 #include <linux/init.h>
   7 #include <linux/mm.h>
   8 #include <linux/memory.h>
   9 #include <linux/vmstat.h>
  10 #include <linux/notifier.h>
  11 #include <linux/node.h>
  12 #include <linux/hugetlb.h>
  13 #include <linux/compaction.h>
  14 #include <linux/cpumask.h>
  15 #include <linux/topology.h>
  16 #include <linux/nodemask.h>
  17 #include <linux/cpu.h>
  18 #include <linux/device.h>
  19 #include <linux/swap.h>
  20 #include <linux/slab.h>
  21
  22 static struct bus_type node_subsys = {
  23         .name = "node",
  24         .dev_name = "node",
  25 };
  26
  27
  28 static ssize_t node_read_cpumap(struct device *dev, bool list, char *buf)
  29 {
  30         ssize_t n;
  31         cpumask_var_t mask;
  32         struct node *node_dev = to_node(dev);
  33
  34         /* 2008/04/07: buf currently PAGE_SIZE, need 9 chars per 32 bits. */
  35         BUILD_BUG_ON((NR_CPUS/32 * 9) > (PAGE_SIZE-1));
  36
  37         if (!alloc_cpumask_var(&mask, GFP_KERNEL))
  38                 return 0;
  39
  40         cpumask_and(mask, cpumask_of_node(node_dev->dev.id), cpu_online_mask);
  41         n = cpumap_print_to_pagebuf(list, buf, mask);
  42         free_cpumask_var(mask);
  43
  44         return n;
  45 }
  46
  47 static inline ssize_t node_read_cpumask(struct device *dev,
  48                                 struct device_attribute *attr, char *buf)
  49 {
  50         return node_read_cpumap(dev, false, buf);
  51 }
  52 static inline ssize_t node_read_cpulist(struct device *dev,
  53                                 struct device_attribute *attr, char *buf)
  54 {
  55         return node_read_cpumap(dev, true, buf);
  56 }
  57
  58 static DEVICE_ATTR(cpumap,  S_IRUGO, node_read_cpumask, NULL);
  59 static DEVICE_ATTR(cpulist, S_IRUGO, node_read_cpulist, NULL);
  60
  61 #define K(x) ((x) << (PAGE_SHIFT - 10))
  62 static ssize_t node_read_meminfo(struct device *dev,
  63                         struct device_attribute *attr, char *buf)
  64 {
  65         int n;
  66         int nid = dev->id;
  67         struct pglist_data *pgdat = NODE_DATA(nid);
  68         struct sysinfo i;
  69
  70         si_meminfo_node(&i, nid);
  71         n = sprintf(buf,
  72                        "Node %d MemTotal:       %8lu kB\n"
  73                        "Node %d MemFree:        %8lu kB\n"
  74                        "Node %d MemUsed:        %8lu kB\n"
  75                        "Node %d Active:         %8lu kB\n"
  76                        "Node %d Inactive:       %8lu kB\n"
  77                        "Node %d Active(anon):   %8lu kB\n"
  78                        "Node %d Inactive(anon): %8lu kB\n"
  79                        "Node %d Active(file):   %8lu kB\n"
  80                        "Node %d Inactive(file): %8lu kB\n"
  81                        "Node %d Unevictable:    %8lu kB\n"
  82                        "Node %d Mlocked:        %8lu kB\n",
  83                        nid, K(i.totalram),
  84                        nid, K(i.freeram),
  85                        nid, K(i.totalram - i.freeram),
  86                        nid, K(node_page_state(pgdat, NR_ACTIVE_ANON) +
  87                                 node_page_state(pgdat, NR_ACTIVE_FILE)),
  88                        nid, K(node_page_state(pgdat, NR_INACTIVE_ANON) +
  89                                 node_page_state(pgdat, NR_INACTIVE_FILE)),
  90                        nid, K(node_page_state(pgdat, NR_ACTIVE_ANON)),
  91                        nid, K(node_page_state(pgdat, NR_INACTIVE_ANON)),
  92                        nid, K(node_page_state(pgdat, NR_ACTIVE_FILE)),
  93                        nid, K(node_page_state(pgdat, NR_INACTIVE_FILE)),
  94                        nid, K(node_page_state(pgdat, NR_UNEVICTABLE)),
  95                        nid, K(sum_zone_node_page_state(nid, NR_MLOCK)));
  96
  97 #ifdef CONFIG_HIGHMEM
  98         n += sprintf(buf + n,
  99                        "Node %d HighTotal:      %8lu kB\n"
 100                        "Node %d HighFree:       %8lu kB\n"
 101                        "Node %d LowTotal:       %8lu kB\n"
 102                        "Node %d LowFree:        %8lu kB\n",
 103                        nid, K(i.totalhigh),
 104                        nid, K(i.freehigh),
 105                        nid, K(i.totalram - i.totalhigh),
 106                        nid, K(i.freeram - i.freehigh));
 107 #endif
 108         n += sprintf(buf + n,
 109                        "Node %d Dirty:          %8lu kB\n"
 110                        "Node %d Writeback:      %8lu kB\n"
 111                        "Node %d FilePages:      %8lu kB\n"
 112                        "Node %d Mapped:         %8lu kB\n"
 113                        "Node %d AnonPages:      %8lu kB\n"
 114                        "Node %d Shmem:          %8lu kB\n"
 115                        "Node %d KernelStack:    %8lu kB\n"
 116                        "Node %d PageTables:     %8lu kB\n"
 117                        "Node %d NFS_Unstable:   %8lu kB\n"
 118                        "Node %d Bounce:         %8lu kB\n"
 119                        "Node %d WritebackTmp:   %8lu kB\n"
 120                        "Node %d Slab:           %8lu kB\n"
 121                        "Node %d SReclaimable:   %8lu kB\n"
 122                        "Node %d SUnreclaim:     %8lu kB\n"
 123 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 124                        "Node %d AnonHugePages:  %8lu kB\n"
 125                        "Node %d ShmemHugePages: %8lu kB\n"
 126                        "Node %d ShmemPmdMapped: %8lu kB\n"
 127 #endif
 128                         ,
 129                        nid, K(node_page_state(pgdat, NR_FILE_DIRTY)),
 130                        nid, K(node_page_state(pgdat, NR_WRITEBACK)),
 131                        nid, K(node_page_state(pgdat, NR_FILE_PAGES)),
 132                        nid, K(node_page_state(pgdat, NR_FILE_MAPPED)),
 133                        nid, K(node_page_state(pgdat, NR_ANON_MAPPED)),
 134                        nid, K(i.sharedram),
 135                        nid, sum_zone_node_page_state(nid, NR_KERNEL_STACK_KB),
 136                        nid, K(sum_zone_node_page_state(nid, NR_PAGETABLE)),
 137                        nid, K(node_page_state(pgdat, NR_UNSTABLE_NFS)),
 138                        nid, K(sum_zone_node_page_state(nid, NR_BOUNCE)),
 139                        nid, K(node_page_state(pgdat, NR_WRITEBACK_TEMP)),
 140                        nid, K(node_page_state(pgdat, NR_SLAB_RECLAIMABLE) +
 141                               node_page_state(pgdat, NR_SLAB_UNRECLAIMABLE)),
 142                        nid, K(node_page_state(pgdat, NR_SLAB_RECLAIMABLE)),
 143 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 144                        nid, K(node_page_state(pgdat, NR_SLAB_UNRECLAIMABLE)),
 145                        nid, K(node_page_state(pgdat, NR_ANON_THPS) *
 146                                        HPAGE_PMD_NR),
 147                        nid, K(node_page_state(pgdat, NR_SHMEM_THPS) *
 148                                        HPAGE_PMD_NR),
 149                        nid, K(node_page_state(pgdat, NR_SHMEM_PMDMAPPED) *
 150                                        HPAGE_PMD_NR));
 151 #else
 152                        nid, K(node_page_state(pgdat, NR_SLAB_UNRECLAIMABLE)));
 153 #endif
 154         n += hugetlb_report_node_meminfo(nid, buf + n);
 155         return n;
 156 }
 157
 158 #undef K
 159 static DEVICE_ATTR(meminfo, S_IRUGO, node_read_meminfo, NULL);
 160
 161 static ssize_t node_read_numastat(struct device *dev,
 162                                 struct device_attribute *attr, char *buf)
 163 {
 164         return sprintf(buf,
 165                        "numa_hit %lu\n"
 166                        "numa_miss %lu\n"
 167                        "numa_foreign %lu\n"
 168                        "interleave_hit %lu\n"
 169                        "local_node %lu\n"
 170                        "other_node %lu\n",
 171                        sum_zone_numa_state(dev->id, NUMA_HIT),
 172                        sum_zone_numa_state(dev->id, NUMA_MISS),
 173                        sum_zone_numa_state(dev->id, NUMA_FOREIGN),
 174                        sum_zone_numa_state(dev->id, NUMA_INTERLEAVE_HIT),
 175                        sum_zone_numa_state(dev->id, NUMA_LOCAL),
 176                        sum_zone_numa_state(dev->id, NUMA_OTHER));
 177 }
 178 static DEVICE_ATTR(numastat, S_IRUGO, node_read_numastat, NULL);
 179
 180 static ssize_t node_read_vmstat(struct device *dev,
 181                                 struct device_attribute *attr, char *buf)
 182 {
 183         int nid = dev->id;
 184         struct pglist_data *pgdat = NODE_DATA(nid);
 185         int i;
 186         int n = 0;
 187
 188         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 189                 n += sprintf(buf+n, "%s %lu\n", vmstat_text[i],
 190                              sum_zone_node_page_state(nid, i));
 191
 192 #ifdef CONFIG_NUMA
 193         for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++)
 194                 n += sprintf(buf+n, "%s %lu\n",
 195                              vmstat_text[i + NR_VM_ZONE_STAT_ITEMS],
 196                              sum_zone_numa_state(nid, i));
 197 #endif
 198
 199         for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
 200                 n += sprintf(buf+n, "%s %lu\n",
 201                              vmstat_text[i + NR_VM_ZONE_STAT_ITEMS +
 202                              NR_VM_NUMA_STAT_ITEMS],
 203                              node_page_state(pgdat, i));
 204
 205         return n;
 206 }
 207 static DEVICE_ATTR(vmstat, S_IRUGO, node_read_vmstat, NULL);
 208
 209 static ssize_t node_read_distance(struct device *dev,
 210                         struct device_attribute *attr, char *buf)
 211 {
 212         int nid = dev->id;
 213         int len = 0;
 214         int i;
 215
 216         /*
 217          * buf is currently PAGE_SIZE in length and each node needs 4 chars
 218          * at the most (distance + space or newline).
 219          */
 220         BUILD_BUG_ON(MAX_NUMNODES * 4 > PAGE_SIZE);
 221
 222         for_each_online_node(i)
 223                 len += sprintf(buf + len, "%s%d", i ? " " : "", node_distance(nid, i));
 224
 225         len += sprintf(buf + len, "\n");
 226         return len;
 227 }
 228 static DEVICE_ATTR(distance, S_IRUGO, node_read_distance, NULL);
 229
 230 static struct attribute *node_dev_attrs[] = {
 231         &dev_attr_cpumap.attr,
 232         &dev_attr_cpulist.attr,
 233         &dev_attr_meminfo.attr,
 234         &dev_attr_numastat.attr,
 235         &dev_attr_distance.attr,
 236         &dev_attr_vmstat.attr,
 237         NULL
 238 };
 239 ATTRIBUTE_GROUPS(node_dev);
 240
 241 #ifdef CONFIG_HUGETLBFS
 242 /*
 243  * hugetlbfs per node attributes registration interface:
 244  * When/if hugetlb[fs] subsystem initializes [sometime after this module],
 245  * it will register its per node attributes for all online nodes with
 246  * memory.  It will also call register_hugetlbfs_with_node(), below, to
 247  * register its attribute registration functions with this node driver.
 248  * Once these hooks have been initialized, the node driver will call into
 249  * the hugetlb module to [un]register attributes for hot-plugged nodes.
 250  */
 251 static node_registration_func_t __hugetlb_register_node;
 252 static node_registration_func_t __hugetlb_unregister_node;
 253
 254 static inline bool hugetlb_register_node(struct node *node)
 255 {
 256         if (__hugetlb_register_node &&
 257                         node_state(node->dev.id, N_MEMORY)) {
 258                 __hugetlb_register_node(node);
 259                 return true;
 260         }
 261         return false;
 262 }
 263
 264 static inline void hugetlb_unregister_node(struct node *node)
 265 {
 266         if (__hugetlb_unregister_node)
 267                 __hugetlb_unregister_node(node);
 268 }
 269
 270 void register_hugetlbfs_with_node(node_registration_func_t doregister,
 271                                   node_registration_func_t unregister)
 272 {
 273         __hugetlb_register_node   = doregister;
 274         __hugetlb_unregister_node = unregister;
 275 }
 276 #else
 277 static inline void hugetlb_register_node(struct node *node) {}
 278
 279 static inline void hugetlb_unregister_node(struct node *node) {}
 280 #endif
 281
 282 static void node_device_release(struct device *dev)
 283 {
 284         struct node *node = to_node(dev);
 285
 286 #if defined(CONFIG_MEMORY_HOTPLUG_SPARSE) && defined(CONFIG_HUGETLBFS)
 287         /*
 288          * We schedule the work only when a memory section is
 289          * onlined/offlined on this node. When we come here,
 290          * all the memory on this node has been offlined,
 291          * so we won't enqueue new work to this work.
 292          *
 293          * The work is using node->node_work, so we should
 294          * flush work before freeing the memory.
 295          */
 296         flush_work(&node->node_work);
 297 #endif
 298         kfree(node);
 299 }
 300
 301 /*
 302  * register_node - Setup a sysfs device for a node.
 303  * @num - Node number to use when creating the device.
 304  *
 305  * Initialize and register the node device.
 306  */
 307 static int register_node(struct node *node, int num)
 308 {
 309         int error;
 310
 311         node->dev.id = num;
 312         node->dev.bus = &node_subsys;
 313         node->dev.release = node_device_release;
 314         node->dev.groups = node_dev_groups;
 315         error = device_register(&node->dev);
 316
 317         if (!error){
 318                 hugetlb_register_node(node);
 319
 320                 compaction_register_node(node);
 321         }
 322         return error;
 323 }
 324
 325 /**
 326  * unregister_node - unregister a node device
 327  * @node: node going away
 328  *
 329  * Unregisters a node device @node.  All the devices on the node must be
 330  * unregistered before calling this function.
 331  */
 332 void unregister_node(struct node *node)
 333 {
 334         hugetlb_unregister_node(node);          /* no-op, if memoryless node */
 335
 336         device_unregister(&node->dev);
 337 }
 338
 339 struct node *node_devices[MAX_NUMNODES];
 340
 341 /*
 342  * register cpu under node
 343  */
 344 int register_cpu_under_node(unsigned int cpu, unsigned int nid)
 345 {
 346         int ret;
 347         struct device *obj;
 348
 349         if (!node_online(nid))
 350                 return 0;
 351
 352         obj = get_cpu_device(cpu);
 353         if (!obj)
 354                 return 0;
 355
 356         ret = sysfs_create_link(&node_devices[nid]->dev.kobj,
 357                                 &obj->kobj,
 358                                 kobject_name(&obj->kobj));
 359         if (ret)
 360                 return ret;
 361
 362         return sysfs_create_link(&obj->kobj,
 363                                  &node_devices[nid]->dev.kobj,
 364                                  kobject_name(&node_devices[nid]->dev.kobj));
 365 }
 366
 367 int unregister_cpu_under_node(unsigned int cpu, unsigned int nid)
 368 {
 369         struct device *obj;
 370
 371         if (!node_online(nid))
 372                 return 0;
 373
 374         obj = get_cpu_device(cpu);
 375         if (!obj)
 376                 return 0;
 377
 378         sysfs_remove_link(&node_devices[nid]->dev.kobj,
 379                           kobject_name(&obj->kobj));
 380         sysfs_remove_link(&obj->kobj,
 381                           kobject_name(&node_devices[nid]->dev.kobj));
 382
 383         return 0;
 384 }
 385
 386 #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
 387 static int __ref get_nid_for_pfn(unsigned long pfn)
 388 {
 389         if (!pfn_valid_within(pfn))
 390                 return -1;
 391 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
 392         if (system_state < SYSTEM_RUNNING)
 393                 return early_pfn_to_nid(pfn);
 394 #endif
 395         return pfn_to_nid(pfn);
 396 }
 397
 398 /* register memory section under specified node if it spans that node */
 399 int register_mem_sect_under_node(struct memory_block *mem_blk, int nid)
 400 {
 401         int ret;
 402         unsigned long pfn, sect_start_pfn, sect_end_pfn;
 403
 404         if (!mem_blk)
 405                 return -EFAULT;
 406         if (!node_online(nid))
 407                 return 0;
 408
 409         sect_start_pfn = section_nr_to_pfn(mem_blk->start_section_nr);
 410         sect_end_pfn = section_nr_to_pfn(mem_blk->end_section_nr);
 411         sect_end_pfn += PAGES_PER_SECTION - 1;
 412         for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
 413                 int page_nid;
 414
 415                 /*
 416                  * memory block could have several absent sections from start.
 417                  * skip pfn range from absent section
 418                  */
 419                 if (!pfn_present(pfn)) {
 420                         pfn = round_down(pfn + PAGES_PER_SECTION,
 421                                          PAGES_PER_SECTION) - 1;
 422                         continue;
 423                 }
 424
 425                 page_nid = get_nid_for_pfn(pfn);
 426                 if (page_nid < 0)
 427                         continue;
 428                 if (page_nid != nid)
 429                         continue;
 430                 ret = sysfs_create_link_nowarn(&node_devices[nid]->dev.kobj,
 431                                         &mem_blk->dev.kobj,
 432                                         kobject_name(&mem_blk->dev.kobj));
 433                 if (ret)
 434                         return ret;
 435
 436                 return sysfs_create_link_nowarn(&mem_blk->dev.kobj,
 437                                 &node_devices[nid]->dev.kobj,
 438                                 kobject_name(&node_devices[nid]->dev.kobj));
 439         }
 440         /* mem section does not span the specified node */
 441         return 0;
 442 }
 443
 444 /* unregister memory section under all nodes that it spans */
 445 int unregister_mem_sect_under_nodes(struct memory_block *mem_blk,
 446                                     unsigned long phys_index)
 447 {
 448         NODEMASK_ALLOC(nodemask_t, unlinked_nodes, GFP_KERNEL);
 449         unsigned long pfn, sect_start_pfn, sect_end_pfn;
 450
 451         if (!mem_blk) {
 452                 NODEMASK_FREE(unlinked_nodes);
 453                 return -EFAULT;
 454         }
 455         if (!unlinked_nodes)
 456                 return -ENOMEM;
 457         nodes_clear(*unlinked_nodes);
 458
 459         sect_start_pfn = section_nr_to_pfn(phys_index);
 460         sect_end_pfn = sect_start_pfn + PAGES_PER_SECTION - 1;
 461         for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
 462                 int nid;
 463
 464                 nid = get_nid_for_pfn(pfn);
 465                 if (nid < 0)
 466                         continue;
 467                 if (!node_online(nid))
 468                         continue;
 469                 if (node_test_and_set(nid, *unlinked_nodes))
 470                         continue;
 471                 sysfs_remove_link(&node_devices[nid]->dev.kobj,
 472                          kobject_name(&mem_blk->dev.kobj));
 473                 sysfs_remove_link(&mem_blk->dev.kobj,
 474                          kobject_name(&node_devices[nid]->dev.kobj));
 475         }
 476         NODEMASK_FREE(unlinked_nodes);
 477         return 0;
 478 }
 479
 480 int link_mem_sections(int nid, unsigned long start_pfn, unsigned long nr_pages)
 481 {
 482         unsigned long end_pfn = start_pfn + nr_pages;
 483         unsigned long pfn;
 484         struct memory_block *mem_blk = NULL;
 485         int err = 0;
 486
 487         for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
 488                 unsigned long section_nr = pfn_to_section_nr(pfn);
 489                 struct mem_section *mem_sect;
 490                 int ret;
 491
 492                 if (!present_section_nr(section_nr))
 493                         continue;
 494                 mem_sect = __nr_to_section(section_nr);
 495
 496                 /* same memblock ? */
 497                 if (mem_blk)
 498                         if ((section_nr >= mem_blk->start_section_nr) &&
 499                             (section_nr <= mem_blk->end_section_nr))
 500                                 continue;
 501
 502                 mem_blk = find_memory_block_hinted(mem_sect, mem_blk);
 503
 504                 ret = register_mem_sect_under_node(mem_blk, nid);
 505                 if (!err)
 506                         err = ret;
 507
 508                 /* discard ref obtained in find_memory_block() */
 509         }
 510
 511         if (mem_blk)
 512                 kobject_put(&mem_blk->dev.kobj);
 513         return err;
 514 }
 515
 516 #ifdef CONFIG_HUGETLBFS
 517 /*
 518  * Handle per node hstate attribute [un]registration on transistions
 519  * to/from memoryless state.
 520  */
 521 static void node_hugetlb_work(struct work_struct *work)
 522 {
 523         struct node *node = container_of(work, struct node, node_work);
 524
 525         /*
 526          * We only get here when a node transitions to/from memoryless state.
 527          * We can detect which transition occurred by examining whether the
 528          * node has memory now.  hugetlb_register_node() already check this
 529          * so we try to register the attributes.  If that fails, then the
 530          * node has transitioned to memoryless, try to unregister the
 531          * attributes.
 532          */
 533         if (!hugetlb_register_node(node))
 534                 hugetlb_unregister_node(node);
 535 }
 536
 537 static void init_node_hugetlb_work(int nid)
 538 {
 539         INIT_WORK(&node_devices[nid]->node_work, node_hugetlb_work);
 540 }
 541
 542 static int node_memory_callback(struct notifier_block *self,
 543                                 unsigned long action, void *arg)
 544 {
 545         struct memory_notify *mnb = arg;
 546         int nid = mnb->status_change_nid;
 547
 548         switch (action) {
 549         case MEM_ONLINE:
 550         case MEM_OFFLINE:
 551                 /*
 552                  * offload per node hstate [un]registration to a work thread
 553                  * when transitioning to/from memoryless state.
 554                  */
 555                 if (nid != NUMA_NO_NODE)
 556                         schedule_work(&node_devices[nid]->node_work);
 557                 break;
 558
 559         case MEM_GOING_ONLINE:
 560         case MEM_GOING_OFFLINE:
 561         case MEM_CANCEL_ONLINE:
 562         case MEM_CANCEL_OFFLINE:
 563         default:
 564                 break;
 565         }
 566
 567         return NOTIFY_OK;
 568 }
 569 #endif  /* CONFIG_HUGETLBFS */
 570 #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
 571
 572 #if !defined(CONFIG_MEMORY_HOTPLUG_SPARSE) || \
 573     !defined(CONFIG_HUGETLBFS)
 574 static inline int node_memory_callback(struct notifier_block *self,
 575                                 unsigned long action, void *arg)
 576 {
 577         return NOTIFY_OK;
 578 }
 579
 580 static void init_node_hugetlb_work(int nid) { }
 581
 582 #endif
 583
 584 int __register_one_node(int nid)
 585 {
 586         int error;
 587         int cpu;
 588
 589         node_devices[nid] = kzalloc(sizeof(struct node), GFP_KERNEL);
 590         if (!node_devices[nid])
 591                 return -ENOMEM;
 592
 593         error = register_node(node_devices[nid], nid);
 594
 595         /* link cpu under this node */
 596         for_each_present_cpu(cpu) {
 597                 if (cpu_to_node(cpu) == nid)
 598                         register_cpu_under_node(cpu, nid);
 599         }
 600
 601         /* initialize work queue for memory hot plug */
 602         init_node_hugetlb_work(nid);
 603
 604         return error;
 605 }
 606
 607 void unregister_one_node(int nid)
 608 {
 609         if (!node_devices[nid])
 610                 return;
 611
 612         unregister_node(node_devices[nid]);
 613         node_devices[nid] = NULL;
 614 }
 615
 616 /*
 617  * node states attributes
 618  */
 619
 620 static ssize_t print_nodes_state(enum node_states state, char *buf)
 621 {
 622         int n;
 623
 624         n = scnprintf(buf, PAGE_SIZE - 1, "%*pbl",
 625                       nodemask_pr_args(&node_states[state]));
 626         buf[n++] = '\n';
 627         buf[n] = '\0';
 628         return n;
 629 }
 630
 631 struct node_attr {
 632         struct device_attribute attr;
 633         enum node_states state;
 634 };
 635
 636 static ssize_t show_node_state(struct device *dev,
 637                                struct device_attribute *attr, char *buf)
 638 {
 639         struct node_attr *na = container_of(attr, struct node_attr, attr);
 640         return print_nodes_state(na->state, buf);
 641 }
 642
 643 #define _NODE_ATTR(name, state) \
 644         { __ATTR(name, 0444, show_node_state, NULL), state }
 645
 646 static struct node_attr node_state_attr[] = {
 647         [N_POSSIBLE] = _NODE_ATTR(possible, N_POSSIBLE),
 648         [N_ONLINE] = _NODE_ATTR(online, N_ONLINE),
 649         [N_NORMAL_MEMORY] = _NODE_ATTR(has_normal_memory, N_NORMAL_MEMORY),
 650 #ifdef CONFIG_HIGHMEM
 651         [N_HIGH_MEMORY] = _NODE_ATTR(has_high_memory, N_HIGH_MEMORY),
 652 #endif
 653         [N_MEMORY] = _NODE_ATTR(has_memory, N_MEMORY),
 654         [N_CPU] = _NODE_ATTR(has_cpu, N_CPU),
 655 };
 656
 657 static struct attribute *node_state_attrs[] = {
 658         &node_state_attr[N_POSSIBLE].attr.attr,
 659         &node_state_attr[N_ONLINE].attr.attr,
 660         &node_state_attr[N_NORMAL_MEMORY].attr.attr,
 661 #ifdef CONFIG_HIGHMEM
 662         &node_state_attr[N_HIGH_MEMORY].attr.attr,
 663 #endif
 664         &node_state_attr[N_MEMORY].attr.attr,
 665         &node_state_attr[N_CPU].attr.attr,
 666         NULL
 667 };
 668
 669 static struct attribute_group memory_root_attr_group = {
 670         .attrs = node_state_attrs,
 671 };
 672
 673 static const struct attribute_group *cpu_root_attr_groups[] = {
 674         &memory_root_attr_group,
 675         NULL,
 676 };
 677
 678 #define NODE_CALLBACK_PRI       2       /* lower than SLAB */
 679 static int __init register_node_type(void)
 680 {
 681         int ret;
 682
 683         BUILD_BUG_ON(ARRAY_SIZE(node_state_attr) != NR_NODE_STATES);
 684         BUILD_BUG_ON(ARRAY_SIZE(node_state_attrs)-1 != NR_NODE_STATES);
 685
 686         ret = subsys_system_register(&node_subsys, cpu_root_attr_groups);
 687         if (!ret) {
 688                 static struct notifier_block node_memory_callback_nb = {
 689                         .notifier_call = node_memory_callback,
 690                         .priority = NODE_CALLBACK_PRI,
 691                 };
 692                 register_hotmemory_notifier(&node_memory_callback_nb);
 693         }
 694
 695         /*
 696          * Note:  we're not going to unregister the node class if we fail
 697          * to register the node state class attribute files.
 698          */
 699         return ret;
 700 }
 701 postcore_initcall(register_node_type);