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         struct node *node_dev = to_node(dev);
  31         const struct cpumask *mask = cpumask_of_node(node_dev->dev.id);
  32
  33         /* 2008/04/07: buf currently PAGE_SIZE, need 9 chars per 32 bits. */
  34         BUILD_BUG_ON((NR_CPUS/32 * 9) > (PAGE_SIZE-1));
  35
  36         return cpumap_print_to_pagebuf(list, buf, mask);
  37 }
  38
  39 static inline ssize_t node_read_cpumask(struct device *dev,
  40                                 struct device_attribute *attr, char *buf)
  41 {
  42         return node_read_cpumap(dev, false, buf);
  43 }
  44 static inline ssize_t node_read_cpulist(struct device *dev,
  45                                 struct device_attribute *attr, char *buf)
  46 {
  47         return node_read_cpumap(dev, true, buf);
  48 }
  49
  50 static DEVICE_ATTR(cpumap,  S_IRUGO, node_read_cpumask, NULL);
  51 static DEVICE_ATTR(cpulist, S_IRUGO, node_read_cpulist, NULL);
  52
  53 #define K(x) ((x) << (PAGE_SHIFT - 10))
  54 static ssize_t node_read_meminfo(struct device *dev,
  55                         struct device_attribute *attr, char *buf)
  56 {
  57         int n;
  58         int nid = dev->id;
  59         struct pglist_data *pgdat = NODE_DATA(nid);
  60         struct sysinfo i;
  61
  62         si_meminfo_node(&i, nid);
  63         n = sprintf(buf,
  64                        "Node %d MemTotal:       %8lu kB\n"
  65                        "Node %d MemFree:        %8lu kB\n"
  66                        "Node %d MemUsed:        %8lu kB\n"
  67                        "Node %d Active:         %8lu kB\n"
  68                        "Node %d Inactive:       %8lu kB\n"
  69                        "Node %d Active(anon):   %8lu kB\n"
  70                        "Node %d Inactive(anon): %8lu kB\n"
  71                        "Node %d Active(file):   %8lu kB\n"
  72                        "Node %d Inactive(file): %8lu kB\n"
  73                        "Node %d Unevictable:    %8lu kB\n"
  74                        "Node %d Mlocked:        %8lu kB\n",
  75                        nid, K(i.totalram),
  76                        nid, K(i.freeram),
  77                        nid, K(i.totalram - i.freeram),
  78                        nid, K(node_page_state(pgdat, NR_ACTIVE_ANON) +
  79                                 node_page_state(pgdat, NR_ACTIVE_FILE)),
  80                        nid, K(node_page_state(pgdat, NR_INACTIVE_ANON) +
  81                                 node_page_state(pgdat, NR_INACTIVE_FILE)),
  82                        nid, K(node_page_state(pgdat, NR_ACTIVE_ANON)),
  83                        nid, K(node_page_state(pgdat, NR_INACTIVE_ANON)),
  84                        nid, K(node_page_state(pgdat, NR_ACTIVE_FILE)),
  85                        nid, K(node_page_state(pgdat, NR_INACTIVE_FILE)),
  86                        nid, K(node_page_state(pgdat, NR_UNEVICTABLE)),
  87                        nid, K(sum_zone_node_page_state(nid, NR_MLOCK)));
  88
  89 #ifdef CONFIG_HIGHMEM
  90         n += sprintf(buf + n,
  91                        "Node %d HighTotal:      %8lu kB\n"
  92                        "Node %d HighFree:       %8lu kB\n"
  93                        "Node %d LowTotal:       %8lu kB\n"
  94                        "Node %d LowFree:        %8lu kB\n",
  95                        nid, K(i.totalhigh),
  96                        nid, K(i.freehigh),
  97                        nid, K(i.totalram - i.totalhigh),
  98                        nid, K(i.freeram - i.freehigh));
  99 #endif
 100         n += sprintf(buf + n,
 101                        "Node %d Dirty:          %8lu kB\n"
 102                        "Node %d Writeback:      %8lu kB\n"
 103                        "Node %d FilePages:      %8lu kB\n"
 104                        "Node %d Mapped:         %8lu kB\n"
 105                        "Node %d AnonPages:      %8lu kB\n"
 106                        "Node %d Shmem:          %8lu kB\n"
 107                        "Node %d KernelStack:    %8lu kB\n"
 108                        "Node %d PageTables:     %8lu kB\n"
 109                        "Node %d NFS_Unstable:   %8lu kB\n"
 110                        "Node %d Bounce:         %8lu kB\n"
 111                        "Node %d WritebackTmp:   %8lu kB\n"
 112                        "Node %d Slab:           %8lu kB\n"
 113                        "Node %d SReclaimable:   %8lu kB\n"
 114                        "Node %d SUnreclaim:     %8lu kB\n"
 115 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 116                        "Node %d AnonHugePages:  %8lu kB\n"
 117                        "Node %d ShmemHugePages: %8lu kB\n"
 118                        "Node %d ShmemPmdMapped: %8lu kB\n"
 119 #endif
 120                         ,
 121                        nid, K(sum_zone_node_page_state(nid, NR_FILE_DIRTY)),
 122                        nid, K(sum_zone_node_page_state(nid, NR_WRITEBACK)),
 123                        nid, K(sum_zone_node_page_state(nid, NR_FILE_PAGES)),
 124                        nid, K(sum_zone_node_page_state(nid, NR_FILE_MAPPED)),
 125                        nid, K(sum_zone_node_page_state(nid, NR_ANON_PAGES)),
 126                        nid, K(i.sharedram),
 127                        nid, sum_zone_node_page_state(nid, NR_KERNEL_STACK) *
 128                                 THREAD_SIZE / 1024,
 129                        nid, K(sum_zone_node_page_state(nid, NR_PAGETABLE)),
 130                        nid, K(sum_zone_node_page_state(nid, NR_UNSTABLE_NFS)),
 131                        nid, K(sum_zone_node_page_state(nid, NR_BOUNCE)),
 132                        nid, K(sum_zone_node_page_state(nid, NR_WRITEBACK_TEMP)),
 133                        nid, K(sum_zone_node_page_state(nid, NR_SLAB_RECLAIMABLE) +
 134                                 sum_zone_node_page_state(nid, NR_SLAB_UNRECLAIMABLE)),
 135                        nid, K(sum_zone_node_page_state(nid, NR_SLAB_RECLAIMABLE)),
 136 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 137                        nid, K(sum_zone_node_page_state(nid, NR_SLAB_UNRECLAIMABLE)),
 138                        nid, K(sum_zone_node_page_state(nid, NR_ANON_THPS) *
 139                                        HPAGE_PMD_NR),
 140                        nid, K(sum_zone_node_page_state(nid, NR_SHMEM_THPS) *
 141                                        HPAGE_PMD_NR),
 142                        nid, K(sum_zone_node_page_state(nid, NR_SHMEM_PMDMAPPED) *
 143                                        HPAGE_PMD_NR));
 144 #else
 145                        nid, K(sum_zone_node_page_state(nid, NR_SLAB_UNRECLAIMABLE)));
 146 #endif
 147         n += hugetlb_report_node_meminfo(nid, buf + n);
 148         return n;
 149 }
 150
 151 #undef K
 152 static DEVICE_ATTR(meminfo, S_IRUGO, node_read_meminfo, NULL);
 153
 154 static ssize_t node_read_numastat(struct device *dev,
 155                                 struct device_attribute *attr, char *buf)
 156 {
 157         return sprintf(buf,
 158                        "numa_hit %lu\n"
 159                        "numa_miss %lu\n"
 160                        "numa_foreign %lu\n"
 161                        "interleave_hit %lu\n"
 162                        "local_node %lu\n"
 163                        "other_node %lu\n",
 164                        sum_zone_node_page_state(dev->id, NUMA_HIT),
 165                        sum_zone_node_page_state(dev->id, NUMA_MISS),
 166                        sum_zone_node_page_state(dev->id, NUMA_FOREIGN),
 167                        sum_zone_node_page_state(dev->id, NUMA_INTERLEAVE_HIT),
 168                        sum_zone_node_page_state(dev->id, NUMA_LOCAL),
 169                        sum_zone_node_page_state(dev->id, NUMA_OTHER));
 170 }
 171 static DEVICE_ATTR(numastat, S_IRUGO, node_read_numastat, NULL);
 172
 173 static ssize_t node_read_vmstat(struct device *dev,
 174                                 struct device_attribute *attr, char *buf)
 175 {
 176         int nid = dev->id;
 177         struct pglist_data *pgdat = NODE_DATA(nid);
 178         int i;
 179         int n = 0;
 180
 181         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 182                 n += sprintf(buf+n, "%s %lu\n", vmstat_text[i],
 183                              sum_zone_node_page_state(nid, i));
 184
 185         for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
 186                 n += sprintf(buf+n, "%s %lu\n",
 187                              vmstat_text[i + NR_VM_ZONE_STAT_ITEMS],
 188                              node_page_state(pgdat, i));
 189
 190         return n;
 191 }
 192 static DEVICE_ATTR(vmstat, S_IRUGO, node_read_vmstat, NULL);
 193
 194 static ssize_t node_read_distance(struct device *dev,
 195                         struct device_attribute *attr, char *buf)
 196 {
 197         int nid = dev->id;
 198         int len = 0;
 199         int i;
 200
 201         /*
 202          * buf is currently PAGE_SIZE in length and each node needs 4 chars
 203          * at the most (distance + space or newline).
 204          */
 205         BUILD_BUG_ON(MAX_NUMNODES * 4 > PAGE_SIZE);
 206
 207         for_each_online_node(i)
 208                 len += sprintf(buf + len, "%s%d", i ? " " : "", node_distance(nid, i));
 209
 210         len += sprintf(buf + len, "\n");
 211         return len;
 212 }
 213 static DEVICE_ATTR(distance, S_IRUGO, node_read_distance, NULL);
 214
 215 static struct attribute *node_dev_attrs[] = {
 216         &dev_attr_cpumap.attr,
 217         &dev_attr_cpulist.attr,
 218         &dev_attr_meminfo.attr,
 219         &dev_attr_numastat.attr,
 220         &dev_attr_distance.attr,
 221         &dev_attr_vmstat.attr,
 222         NULL
 223 };
 224 ATTRIBUTE_GROUPS(node_dev);
 225
 226 #ifdef CONFIG_HUGETLBFS
 227 /*
 228  * hugetlbfs per node attributes registration interface:
 229  * When/if hugetlb[fs] subsystem initializes [sometime after this module],
 230  * it will register its per node attributes for all online nodes with
 231  * memory.  It will also call register_hugetlbfs_with_node(), below, to
 232  * register its attribute registration functions with this node driver.
 233  * Once these hooks have been initialized, the node driver will call into
 234  * the hugetlb module to [un]register attributes for hot-plugged nodes.
 235  */
 236 static node_registration_func_t __hugetlb_register_node;
 237 static node_registration_func_t __hugetlb_unregister_node;
 238
 239 static inline bool hugetlb_register_node(struct node *node)
 240 {
 241         if (__hugetlb_register_node &&
 242                         node_state(node->dev.id, N_MEMORY)) {
 243                 __hugetlb_register_node(node);
 244                 return true;
 245         }
 246         return false;
 247 }
 248
 249 static inline void hugetlb_unregister_node(struct node *node)
 250 {
 251         if (__hugetlb_unregister_node)
 252                 __hugetlb_unregister_node(node);
 253 }
 254
 255 void register_hugetlbfs_with_node(node_registration_func_t doregister,
 256                                   node_registration_func_t unregister)
 257 {
 258         __hugetlb_register_node   = doregister;
 259         __hugetlb_unregister_node = unregister;
 260 }
 261 #else
 262 static inline void hugetlb_register_node(struct node *node) {}
 263
 264 static inline void hugetlb_unregister_node(struct node *node) {}
 265 #endif
 266
 267 static void node_device_release(struct device *dev)
 268 {
 269         struct node *node = to_node(dev);
 270
 271 #if defined(CONFIG_MEMORY_HOTPLUG_SPARSE) && defined(CONFIG_HUGETLBFS)
 272         /*
 273          * We schedule the work only when a memory section is
 274          * onlined/offlined on this node. When we come here,
 275          * all the memory on this node has been offlined,
 276          * so we won't enqueue new work to this work.
 277          *
 278          * The work is using node->node_work, so we should
 279          * flush work before freeing the memory.
 280          */
 281         flush_work(&node->node_work);
 282 #endif
 283         kfree(node);
 284 }
 285
 286 /*
 287  * register_node - Setup a sysfs device for a node.
 288  * @num - Node number to use when creating the device.
 289  *
 290  * Initialize and register the node device.
 291  */
 292 static int register_node(struct node *node, int num, struct node *parent)
 293 {
 294         int error;
 295
 296         node->dev.id = num;
 297         node->dev.bus = &node_subsys;
 298         node->dev.release = node_device_release;
 299         node->dev.groups = node_dev_groups;
 300         error = device_register(&node->dev);
 301
 302         if (!error){
 303                 hugetlb_register_node(node);
 304
 305                 compaction_register_node(node);
 306         }
 307         return error;
 308 }
 309
 310 /**
 311  * unregister_node - unregister a node device
 312  * @node: node going away
 313  *
 314  * Unregisters a node device @node.  All the devices on the node must be
 315  * unregistered before calling this function.
 316  */
 317 void unregister_node(struct node *node)
 318 {
 319         hugetlb_unregister_node(node);          /* no-op, if memoryless node */
 320
 321         device_unregister(&node->dev);
 322 }
 323
 324 struct node *node_devices[MAX_NUMNODES];
 325
 326 /*
 327  * register cpu under node
 328  */
 329 int register_cpu_under_node(unsigned int cpu, unsigned int nid)
 330 {
 331         int ret;
 332         struct device *obj;
 333
 334         if (!node_online(nid))
 335                 return 0;
 336
 337         obj = get_cpu_device(cpu);
 338         if (!obj)
 339                 return 0;
 340
 341         ret = sysfs_create_link(&node_devices[nid]->dev.kobj,
 342                                 &obj->kobj,
 343                                 kobject_name(&obj->kobj));
 344         if (ret)
 345                 return ret;
 346
 347         return sysfs_create_link(&obj->kobj,
 348                                  &node_devices[nid]->dev.kobj,
 349                                  kobject_name(&node_devices[nid]->dev.kobj));
 350 }
 351
 352 int unregister_cpu_under_node(unsigned int cpu, unsigned int nid)
 353 {
 354         struct device *obj;
 355
 356         if (!node_online(nid))
 357                 return 0;
 358
 359         obj = get_cpu_device(cpu);
 360         if (!obj)
 361                 return 0;
 362
 363         sysfs_remove_link(&node_devices[nid]->dev.kobj,
 364                           kobject_name(&obj->kobj));
 365         sysfs_remove_link(&obj->kobj,
 366                           kobject_name(&node_devices[nid]->dev.kobj));
 367
 368         return 0;
 369 }
 370
 371 #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
 372 #define page_initialized(page)  (page->lru.next)
 373
 374 static int __init_refok get_nid_for_pfn(unsigned long pfn)
 375 {
 376         struct page *page;
 377
 378         if (!pfn_valid_within(pfn))
 379                 return -1;
 380 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
 381         if (system_state == SYSTEM_BOOTING)
 382                 return early_pfn_to_nid(pfn);
 383 #endif
 384         page = pfn_to_page(pfn);
 385         if (!page_initialized(page))
 386                 return -1;
 387         return pfn_to_nid(pfn);
 388 }
 389
 390 /* register memory section under specified node if it spans that node */
 391 int register_mem_sect_under_node(struct memory_block *mem_blk, int nid)
 392 {
 393         int ret;
 394         unsigned long pfn, sect_start_pfn, sect_end_pfn;
 395
 396         if (!mem_blk)
 397                 return -EFAULT;
 398         if (!node_online(nid))
 399                 return 0;
 400
 401         sect_start_pfn = section_nr_to_pfn(mem_blk->start_section_nr);
 402         sect_end_pfn = section_nr_to_pfn(mem_blk->end_section_nr);
 403         sect_end_pfn += PAGES_PER_SECTION - 1;
 404         for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
 405                 int page_nid;
 406
 407                 /*
 408                  * memory block could have several absent sections from start.
 409                  * skip pfn range from absent section
 410                  */
 411                 if (!pfn_present(pfn)) {
 412                         pfn = round_down(pfn + PAGES_PER_SECTION,
 413                                          PAGES_PER_SECTION) - 1;
 414                         continue;
 415                 }
 416
 417                 page_nid = get_nid_for_pfn(pfn);
 418                 if (page_nid < 0)
 419                         continue;
 420                 if (page_nid != nid)
 421                         continue;
 422                 ret = sysfs_create_link_nowarn(&node_devices[nid]->dev.kobj,
 423                                         &mem_blk->dev.kobj,
 424                                         kobject_name(&mem_blk->dev.kobj));
 425                 if (ret)
 426                         return ret;
 427
 428                 return sysfs_create_link_nowarn(&mem_blk->dev.kobj,
 429                                 &node_devices[nid]->dev.kobj,
 430                                 kobject_name(&node_devices[nid]->dev.kobj));
 431         }
 432         /* mem section does not span the specified node */
 433         return 0;
 434 }
 435
 436 /* unregister memory section under all nodes that it spans */
 437 int unregister_mem_sect_under_nodes(struct memory_block *mem_blk,
 438                                     unsigned long phys_index)
 439 {
 440         NODEMASK_ALLOC(nodemask_t, unlinked_nodes, GFP_KERNEL);
 441         unsigned long pfn, sect_start_pfn, sect_end_pfn;
 442
 443         if (!mem_blk) {
 444                 NODEMASK_FREE(unlinked_nodes);
 445                 return -EFAULT;
 446         }
 447         if (!unlinked_nodes)
 448                 return -ENOMEM;
 449         nodes_clear(*unlinked_nodes);
 450
 451         sect_start_pfn = section_nr_to_pfn(phys_index);
 452         sect_end_pfn = sect_start_pfn + PAGES_PER_SECTION - 1;
 453         for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
 454                 int nid;
 455
 456                 nid = get_nid_for_pfn(pfn);
 457                 if (nid < 0)
 458                         continue;
 459                 if (!node_online(nid))
 460                         continue;
 461                 if (node_test_and_set(nid, *unlinked_nodes))
 462                         continue;
 463                 sysfs_remove_link(&node_devices[nid]->dev.kobj,
 464                          kobject_name(&mem_blk->dev.kobj));
 465                 sysfs_remove_link(&mem_blk->dev.kobj,
 466                          kobject_name(&node_devices[nid]->dev.kobj));
 467         }
 468         NODEMASK_FREE(unlinked_nodes);
 469         return 0;
 470 }
 471
 472 static int link_mem_sections(int nid)
 473 {
 474         unsigned long start_pfn = NODE_DATA(nid)->node_start_pfn;
 475         unsigned long end_pfn = start_pfn + NODE_DATA(nid)->node_spanned_pages;
 476         unsigned long pfn;
 477         struct memory_block *mem_blk = NULL;
 478         int err = 0;
 479
 480         for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
 481                 unsigned long section_nr = pfn_to_section_nr(pfn);
 482                 struct mem_section *mem_sect;
 483                 int ret;
 484
 485                 if (!present_section_nr(section_nr))
 486                         continue;
 487                 mem_sect = __nr_to_section(section_nr);
 488
 489                 /* same memblock ? */
 490                 if (mem_blk)
 491                         if ((section_nr >= mem_blk->start_section_nr) &&
 492                             (section_nr <= mem_blk->end_section_nr))
 493                                 continue;
 494
 495                 mem_blk = find_memory_block_hinted(mem_sect, mem_blk);
 496
 497                 ret = register_mem_sect_under_node(mem_blk, nid);
 498                 if (!err)
 499                         err = ret;
 500
 501                 /* discard ref obtained in find_memory_block() */
 502         }
 503
 504         if (mem_blk)
 505                 kobject_put(&mem_blk->dev.kobj);
 506         return err;
 507 }
 508
 509 #ifdef CONFIG_HUGETLBFS
 510 /*
 511  * Handle per node hstate attribute [un]registration on transistions
 512  * to/from memoryless state.
 513  */
 514 static void node_hugetlb_work(struct work_struct *work)
 515 {
 516         struct node *node = container_of(work, struct node, node_work);
 517
 518         /*
 519          * We only get here when a node transitions to/from memoryless state.
 520          * We can detect which transition occurred by examining whether the
 521          * node has memory now.  hugetlb_register_node() already check this
 522          * so we try to register the attributes.  If that fails, then the
 523          * node has transitioned to memoryless, try to unregister the
 524          * attributes.
 525          */
 526         if (!hugetlb_register_node(node))
 527                 hugetlb_unregister_node(node);
 528 }
 529
 530 static void init_node_hugetlb_work(int nid)
 531 {
 532         INIT_WORK(&node_devices[nid]->node_work, node_hugetlb_work);
 533 }
 534
 535 static int node_memory_callback(struct notifier_block *self,
 536                                 unsigned long action, void *arg)
 537 {
 538         struct memory_notify *mnb = arg;
 539         int nid = mnb->status_change_nid;
 540
 541         switch (action) {
 542         case MEM_ONLINE:
 543         case MEM_OFFLINE:
 544                 /*
 545                  * offload per node hstate [un]registration to a work thread
 546                  * when transitioning to/from memoryless state.
 547                  */
 548                 if (nid != NUMA_NO_NODE)
 549                         schedule_work(&node_devices[nid]->node_work);
 550                 break;
 551
 552         case MEM_GOING_ONLINE:
 553         case MEM_GOING_OFFLINE:
 554         case MEM_CANCEL_ONLINE:
 555         case MEM_CANCEL_OFFLINE:
 556         default:
 557                 break;
 558         }
 559
 560         return NOTIFY_OK;
 561 }
 562 #endif  /* CONFIG_HUGETLBFS */
 563 #else   /* !CONFIG_MEMORY_HOTPLUG_SPARSE */
 564
 565 static int link_mem_sections(int nid) { return 0; }
 566 #endif  /* CONFIG_MEMORY_HOTPLUG_SPARSE */
 567
 568 #if !defined(CONFIG_MEMORY_HOTPLUG_SPARSE) || \
 569     !defined(CONFIG_HUGETLBFS)
 570 static inline int node_memory_callback(struct notifier_block *self,
 571                                 unsigned long action, void *arg)
 572 {
 573         return NOTIFY_OK;
 574 }
 575
 576 static void init_node_hugetlb_work(int nid) { }
 577
 578 #endif
 579
 580 int register_one_node(int nid)
 581 {
 582         int error = 0;
 583         int cpu;
 584
 585         if (node_online(nid)) {
 586                 int p_node = parent_node(nid);
 587                 struct node *parent = NULL;
 588
 589                 if (p_node != nid)
 590                         parent = node_devices[p_node];
 591
 592                 node_devices[nid] = kzalloc(sizeof(struct node), GFP_KERNEL);
 593                 if (!node_devices[nid])
 594                         return -ENOMEM;
 595
 596                 error = register_node(node_devices[nid], nid, parent);
 597
 598                 /* link cpu under this node */
 599                 for_each_present_cpu(cpu) {
 600                         if (cpu_to_node(cpu) == nid)
 601                                 register_cpu_under_node(cpu, nid);
 602                 }
 603
 604                 /* link memory sections under this node */
 605                 error = link_mem_sections(nid);
 606
 607                 /* initialize work queue for memory hot plug */
 608                 init_node_hugetlb_work(nid);
 609         }
 610
 611         return error;
 612
 613 }
 614
 615 void unregister_one_node(int nid)
 616 {
 617         if (!node_devices[nid])
 618                 return;
 619
 620         unregister_node(node_devices[nid]);
 621         node_devices[nid] = NULL;
 622 }
 623
 624 /*
 625  * node states attributes
 626  */
 627
 628 static ssize_t print_nodes_state(enum node_states state, char *buf)
 629 {
 630         int n;
 631
 632         n = scnprintf(buf, PAGE_SIZE - 1, "%*pbl",
 633                       nodemask_pr_args(&node_states[state]));
 634         buf[n++] = '\n';
 635         buf[n] = '\0';
 636         return n;
 637 }
 638
 639 struct node_attr {
 640         struct device_attribute attr;
 641         enum node_states state;
 642 };
 643
 644 static ssize_t show_node_state(struct device *dev,
 645                                struct device_attribute *attr, char *buf)
 646 {
 647         struct node_attr *na = container_of(attr, struct node_attr, attr);
 648         return print_nodes_state(na->state, buf);
 649 }
 650
 651 #define _NODE_ATTR(name, state) \
 652         { __ATTR(name, 0444, show_node_state, NULL), state }
 653
 654 static struct node_attr node_state_attr[] = {
 655         [N_POSSIBLE] = _NODE_ATTR(possible, N_POSSIBLE),
 656         [N_ONLINE] = _NODE_ATTR(online, N_ONLINE),
 657         [N_NORMAL_MEMORY] = _NODE_ATTR(has_normal_memory, N_NORMAL_MEMORY),
 658 #ifdef CONFIG_HIGHMEM
 659         [N_HIGH_MEMORY] = _NODE_ATTR(has_high_memory, N_HIGH_MEMORY),
 660 #endif
 661 #ifdef CONFIG_MOVABLE_NODE
 662         [N_MEMORY] = _NODE_ATTR(has_memory, N_MEMORY),
 663 #endif
 664         [N_CPU] = _NODE_ATTR(has_cpu, N_CPU),
 665 };
 666
 667 static struct attribute *node_state_attrs[] = {
 668         &node_state_attr[N_POSSIBLE].attr.attr,
 669         &node_state_attr[N_ONLINE].attr.attr,
 670         &node_state_attr[N_NORMAL_MEMORY].attr.attr,
 671 #ifdef CONFIG_HIGHMEM
 672         &node_state_attr[N_HIGH_MEMORY].attr.attr,
 673 #endif
 674 #ifdef CONFIG_MOVABLE_NODE
 675         &node_state_attr[N_MEMORY].attr.attr,
 676 #endif
 677         &node_state_attr[N_CPU].attr.attr,
 678         NULL
 679 };
 680
 681 static struct attribute_group memory_root_attr_group = {
 682         .attrs = node_state_attrs,
 683 };
 684
 685 static const struct attribute_group *cpu_root_attr_groups[] = {
 686         &memory_root_attr_group,
 687         NULL,
 688 };
 689
 690 #define NODE_CALLBACK_PRI       2       /* lower than SLAB */
 691 static int __init register_node_type(void)
 692 {
 693         int ret;
 694
 695         BUILD_BUG_ON(ARRAY_SIZE(node_state_attr) != NR_NODE_STATES);
 696         BUILD_BUG_ON(ARRAY_SIZE(node_state_attrs)-1 != NR_NODE_STATES);
 697
 698         ret = subsys_system_register(&node_subsys, cpu_root_attr_groups);
 699         if (!ret) {
 700                 static struct notifier_block node_memory_callback_nb = {
 701                         .notifier_call = node_memory_callback,
 702                         .priority = NODE_CALLBACK_PRI,
 703                 };
 704                 register_hotmemory_notifier(&node_memory_callback_nb);
 705         }
 706
 707         /*
 708          * Note:  we're not going to unregister the node class if we fail
 709          * to register the node state class attribute files.
 710          */
 711         return ret;
 712 }
 713 postcore_initcall(register_node_type);