drivers/base/node.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Basic Node interface support
   4  */
   5
   6 #include <linux/module.h>
   7 #include <linux/init.h>
   8 #include <linux/mm.h>
   9 #include <linux/memory.h>
  10 #include <linux/vmstat.h>
  11 #include <linux/notifier.h>
  12 #include <linux/node.h>
  13 #include <linux/hugetlb.h>
  14 #include <linux/compaction.h>
  15 #include <linux/cpumask.h>
  16 #include <linux/topology.h>
  17 #include <linux/nodemask.h>
  18 #include <linux/cpu.h>
  19 #include <linux/device.h>
  20 #include <linux/swap.h>
  21 #include <linux/slab.h>
  22
  23 static struct bus_type node_subsys = {
  24         .name = "node",
  25         .dev_name = "node",
  26 };
  27
  28
  29 static ssize_t node_read_cpumap(struct device *dev, bool list, char *buf)
  30 {
  31         ssize_t n;
  32         cpumask_var_t mask;
  33         struct node *node_dev = to_node(dev);
  34
  35         /* 2008/04/07: buf currently PAGE_SIZE, need 9 chars per 32 bits. */
  36         BUILD_BUG_ON((NR_CPUS/32 * 9) > (PAGE_SIZE-1));
  37
  38         if (!alloc_cpumask_var(&mask, GFP_KERNEL))
  39                 return 0;
  40
  41         cpumask_and(mask, cpumask_of_node(node_dev->dev.id), cpu_online_mask);
  42         n = cpumap_print_to_pagebuf(list, buf, mask);
  43         free_cpumask_var(mask);
  44
  45         return n;
  46 }
  47
  48 static inline ssize_t node_read_cpumask(struct device *dev,
  49                                 struct device_attribute *attr, char *buf)
  50 {
  51         return node_read_cpumap(dev, false, buf);
  52 }
  53 static inline ssize_t node_read_cpulist(struct device *dev,
  54                                 struct device_attribute *attr, char *buf)
  55 {
  56         return node_read_cpumap(dev, true, buf);
  57 }
  58
  59 static DEVICE_ATTR(cpumap,  S_IRUGO, node_read_cpumask, NULL);
  60 static DEVICE_ATTR(cpulist, S_IRUGO, node_read_cpulist, NULL);
  61
  62 #define K(x) ((x) << (PAGE_SHIFT - 10))
  63 static ssize_t node_read_meminfo(struct device *dev,
  64                         struct device_attribute *attr, char *buf)
  65 {
  66         int n;
  67         int nid = dev->id;
  68         struct pglist_data *pgdat = NODE_DATA(nid);
  69         struct sysinfo i;
  70         unsigned long sreclaimable, sunreclaimable;
  71
  72         si_meminfo_node(&i, nid);
  73         sreclaimable = node_page_state(pgdat, NR_SLAB_RECLAIMABLE);
  74         sunreclaimable = node_page_state(pgdat, NR_SLAB_UNRECLAIMABLE);
  75         n = sprintf(buf,
  76                        "Node %d MemTotal:       %8lu kB\n"
  77                        "Node %d MemFree:        %8lu kB\n"
  78                        "Node %d MemUsed:        %8lu kB\n"
  79                        "Node %d Active:         %8lu kB\n"
  80                        "Node %d Inactive:       %8lu kB\n"
  81                        "Node %d Active(anon):   %8lu kB\n"
  82                        "Node %d Inactive(anon): %8lu kB\n"
  83                        "Node %d Active(file):   %8lu kB\n"
  84                        "Node %d Inactive(file): %8lu kB\n"
  85                        "Node %d Unevictable:    %8lu kB\n"
  86                        "Node %d Mlocked:        %8lu kB\n",
  87                        nid, K(i.totalram),
  88                        nid, K(i.freeram),
  89                        nid, K(i.totalram - i.freeram),
  90                        nid, K(node_page_state(pgdat, NR_ACTIVE_ANON) +
  91                                 node_page_state(pgdat, NR_ACTIVE_FILE)),
  92                        nid, K(node_page_state(pgdat, NR_INACTIVE_ANON) +
  93                                 node_page_state(pgdat, NR_INACTIVE_FILE)),
  94                        nid, K(node_page_state(pgdat, NR_ACTIVE_ANON)),
  95                        nid, K(node_page_state(pgdat, NR_INACTIVE_ANON)),
  96                        nid, K(node_page_state(pgdat, NR_ACTIVE_FILE)),
  97                        nid, K(node_page_state(pgdat, NR_INACTIVE_FILE)),
  98                        nid, K(node_page_state(pgdat, NR_UNEVICTABLE)),
  99                        nid, K(sum_zone_node_page_state(nid, NR_MLOCK)));
 100
 101 #ifdef CONFIG_HIGHMEM
 102         n += sprintf(buf + n,
 103                        "Node %d HighTotal:      %8lu kB\n"
 104                        "Node %d HighFree:       %8lu kB\n"
 105                        "Node %d LowTotal:       %8lu kB\n"
 106                        "Node %d LowFree:        %8lu kB\n",
 107                        nid, K(i.totalhigh),
 108                        nid, K(i.freehigh),
 109                        nid, K(i.totalram - i.totalhigh),
 110                        nid, K(i.freeram - i.freehigh));
 111 #endif
 112         n += sprintf(buf + n,
 113                        "Node %d Dirty:          %8lu kB\n"
 114                        "Node %d Writeback:      %8lu kB\n"
 115                        "Node %d FilePages:      %8lu kB\n"
 116                        "Node %d Mapped:         %8lu kB\n"
 117                        "Node %d AnonPages:      %8lu kB\n"
 118                        "Node %d Shmem:          %8lu kB\n"
 119                        "Node %d KernelStack:    %8lu kB\n"
 120                        "Node %d PageTables:     %8lu kB\n"
 121                        "Node %d NFS_Unstable:   %8lu kB\n"
 122                        "Node %d Bounce:         %8lu kB\n"
 123                        "Node %d WritebackTmp:   %8lu kB\n"
 124                        "Node %d KReclaimable:   %8lu kB\n"
 125                        "Node %d Slab:           %8lu kB\n"
 126                        "Node %d SReclaimable:   %8lu kB\n"
 127                        "Node %d SUnreclaim:     %8lu kB\n"
 128 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 129                        "Node %d AnonHugePages:  %8lu kB\n"
 130                        "Node %d ShmemHugePages: %8lu kB\n"
 131                        "Node %d ShmemPmdMapped: %8lu kB\n"
 132 #endif
 133                         ,
 134                        nid, K(node_page_state(pgdat, NR_FILE_DIRTY)),
 135                        nid, K(node_page_state(pgdat, NR_WRITEBACK)),
 136                        nid, K(node_page_state(pgdat, NR_FILE_PAGES)),
 137                        nid, K(node_page_state(pgdat, NR_FILE_MAPPED)),
 138                        nid, K(node_page_state(pgdat, NR_ANON_MAPPED)),
 139                        nid, K(i.sharedram),
 140                        nid, sum_zone_node_page_state(nid, NR_KERNEL_STACK_KB),
 141                        nid, K(sum_zone_node_page_state(nid, NR_PAGETABLE)),
 142                        nid, K(node_page_state(pgdat, NR_UNSTABLE_NFS)),
 143                        nid, K(sum_zone_node_page_state(nid, NR_BOUNCE)),
 144                        nid, K(node_page_state(pgdat, NR_WRITEBACK_TEMP)),
 145                        nid, K(sreclaimable +
 146                               node_page_state(pgdat, NR_KERNEL_MISC_RECLAIMABLE)),
 147                        nid, K(sreclaimable + sunreclaimable),
 148                        nid, K(sreclaimable),
 149                        nid, K(sunreclaimable)
 150 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 151                        ,
 152                        nid, K(node_page_state(pgdat, NR_ANON_THPS) *
 153                                        HPAGE_PMD_NR),
 154                        nid, K(node_page_state(pgdat, NR_SHMEM_THPS) *
 155                                        HPAGE_PMD_NR),
 156                        nid, K(node_page_state(pgdat, NR_SHMEM_PMDMAPPED) *
 157                                        HPAGE_PMD_NR)
 158 #endif
 159                        );
 160         n += hugetlb_report_node_meminfo(nid, buf + n);
 161         return n;
 162 }
 163
 164 #undef K
 165 static DEVICE_ATTR(meminfo, S_IRUGO, node_read_meminfo, NULL);
 166
 167 static ssize_t node_read_numastat(struct device *dev,
 168                                 struct device_attribute *attr, char *buf)
 169 {
 170         return sprintf(buf,
 171                        "numa_hit %lu\n"
 172                        "numa_miss %lu\n"
 173                        "numa_foreign %lu\n"
 174                        "interleave_hit %lu\n"
 175                        "local_node %lu\n"
 176                        "other_node %lu\n",
 177                        sum_zone_numa_state(dev->id, NUMA_HIT),
 178                        sum_zone_numa_state(dev->id, NUMA_MISS),
 179                        sum_zone_numa_state(dev->id, NUMA_FOREIGN),
 180                        sum_zone_numa_state(dev->id, NUMA_INTERLEAVE_HIT),
 181                        sum_zone_numa_state(dev->id, NUMA_LOCAL),
 182                        sum_zone_numa_state(dev->id, NUMA_OTHER));
 183 }
 184 static DEVICE_ATTR(numastat, S_IRUGO, node_read_numastat, NULL);
 185
 186 static ssize_t node_read_vmstat(struct device *dev,
 187                                 struct device_attribute *attr, char *buf)
 188 {
 189         int nid = dev->id;
 190         struct pglist_data *pgdat = NODE_DATA(nid);
 191         int i;
 192         int n = 0;
 193
 194         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 195                 n += sprintf(buf+n, "%s %lu\n", vmstat_text[i],
 196                              sum_zone_node_page_state(nid, i));
 197
 198 #ifdef CONFIG_NUMA
 199         for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++)
 200                 n += sprintf(buf+n, "%s %lu\n",
 201                              vmstat_text[i + NR_VM_ZONE_STAT_ITEMS],
 202                              sum_zone_numa_state(nid, i));
 203 #endif
 204
 205         for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
 206                 n += sprintf(buf+n, "%s %lu\n",
 207                              vmstat_text[i + NR_VM_ZONE_STAT_ITEMS +
 208                              NR_VM_NUMA_STAT_ITEMS],
 209                              node_page_state(pgdat, i));
 210
 211         return n;
 212 }
 213 static DEVICE_ATTR(vmstat, S_IRUGO, node_read_vmstat, NULL);
 214
 215 static ssize_t node_read_distance(struct device *dev,
 216                         struct device_attribute *attr, char *buf)
 217 {
 218         int nid = dev->id;
 219         int len = 0;
 220         int i;
 221
 222         /*
 223          * buf is currently PAGE_SIZE in length and each node needs 4 chars
 224          * at the most (distance + space or newline).
 225          */
 226         BUILD_BUG_ON(MAX_NUMNODES * 4 > PAGE_SIZE);
 227
 228         for_each_online_node(i)
 229                 len += sprintf(buf + len, "%s%d", i ? " " : "", node_distance(nid, i));
 230
 231         len += sprintf(buf + len, "\n");
 232         return len;
 233 }
 234 static DEVICE_ATTR(distance, S_IRUGO, node_read_distance, NULL);
 235
 236 static struct attribute *node_dev_attrs[] = {
 237         &dev_attr_cpumap.attr,
 238         &dev_attr_cpulist.attr,
 239         &dev_attr_meminfo.attr,
 240         &dev_attr_numastat.attr,
 241         &dev_attr_distance.attr,
 242         &dev_attr_vmstat.attr,
 243         NULL
 244 };
 245 ATTRIBUTE_GROUPS(node_dev);
 246
 247 #ifdef CONFIG_HUGETLBFS
 248 /*
 249  * hugetlbfs per node attributes registration interface:
 250  * When/if hugetlb[fs] subsystem initializes [sometime after this module],
 251  * it will register its per node attributes for all online nodes with
 252  * memory.  It will also call register_hugetlbfs_with_node(), below, to
 253  * register its attribute registration functions with this node driver.
 254  * Once these hooks have been initialized, the node driver will call into
 255  * the hugetlb module to [un]register attributes for hot-plugged nodes.
 256  */
 257 static node_registration_func_t __hugetlb_register_node;
 258 static node_registration_func_t __hugetlb_unregister_node;
 259
 260 static inline bool hugetlb_register_node(struct node *node)
 261 {
 262         if (__hugetlb_register_node &&
 263                         node_state(node->dev.id, N_MEMORY)) {
 264                 __hugetlb_register_node(node);
 265                 return true;
 266         }
 267         return false;
 268 }
 269
 270 static inline void hugetlb_unregister_node(struct node *node)
 271 {
 272         if (__hugetlb_unregister_node)
 273                 __hugetlb_unregister_node(node);
 274 }
 275
 276 void register_hugetlbfs_with_node(node_registration_func_t doregister,
 277                                   node_registration_func_t unregister)
 278 {
 279         __hugetlb_register_node   = doregister;
 280         __hugetlb_unregister_node = unregister;
 281 }
 282 #else
 283 static inline void hugetlb_register_node(struct node *node) {}
 284
 285 static inline void hugetlb_unregister_node(struct node *node) {}
 286 #endif
 287
 288 static void node_device_release(struct device *dev)
 289 {
 290         struct node *node = to_node(dev);
 291
 292 #if defined(CONFIG_MEMORY_HOTPLUG_SPARSE) && defined(CONFIG_HUGETLBFS)
 293         /*
 294          * We schedule the work only when a memory section is
 295          * onlined/offlined on this node. When we come here,
 296          * all the memory on this node has been offlined,
 297          * so we won't enqueue new work to this work.
 298          *
 299          * The work is using node->node_work, so we should
 300          * flush work before freeing the memory.
 301          */
 302         flush_work(&node->node_work);
 303 #endif
 304         kfree(node);
 305 }
 306
 307 /*
 308  * register_node - Setup a sysfs device for a node.
 309  * @num - Node number to use when creating the device.
 310  *
 311  * Initialize and register the node device.
 312  */
 313 static int register_node(struct node *node, int num)
 314 {
 315         int error;
 316
 317         node->dev.id = num;
 318         node->dev.bus = &node_subsys;
 319         node->dev.release = node_device_release;
 320         node->dev.groups = node_dev_groups;
 321         error = device_register(&node->dev);
 322
 323         if (error)
 324                 put_device(&node->dev);
 325         else {
 326                 hugetlb_register_node(node);
 327
 328                 compaction_register_node(node);
 329         }
 330         return error;
 331 }
 332
 333 /**
 334  * unregister_node - unregister a node device
 335  * @node: node going away
 336  *
 337  * Unregisters a node device @node.  All the devices on the node must be
 338  * unregistered before calling this function.
 339  */
 340 void unregister_node(struct node *node)
 341 {
 342         hugetlb_unregister_node(node);          /* no-op, if memoryless node */
 343
 344         device_unregister(&node->dev);
 345 }
 346
 347 struct node *node_devices[MAX_NUMNODES];
 348
 349 /*
 350  * register cpu under node
 351  */
 352 int register_cpu_under_node(unsigned int cpu, unsigned int nid)
 353 {
 354         int ret;
 355         struct device *obj;
 356
 357         if (!node_online(nid))
 358                 return 0;
 359
 360         obj = get_cpu_device(cpu);
 361         if (!obj)
 362                 return 0;
 363
 364         ret = sysfs_create_link(&node_devices[nid]->dev.kobj,
 365                                 &obj->kobj,
 366                                 kobject_name(&obj->kobj));
 367         if (ret)
 368                 return ret;
 369
 370         return sysfs_create_link(&obj->kobj,
 371                                  &node_devices[nid]->dev.kobj,
 372                                  kobject_name(&node_devices[nid]->dev.kobj));
 373 }
 374
 375 int unregister_cpu_under_node(unsigned int cpu, unsigned int nid)
 376 {
 377         struct device *obj;
 378
 379         if (!node_online(nid))
 380                 return 0;
 381
 382         obj = get_cpu_device(cpu);
 383         if (!obj)
 384                 return 0;
 385
 386         sysfs_remove_link(&node_devices[nid]->dev.kobj,
 387                           kobject_name(&obj->kobj));
 388         sysfs_remove_link(&obj->kobj,
 389                           kobject_name(&node_devices[nid]->dev.kobj));
 390
 391         return 0;
 392 }
 393
 394 #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
 395 static int __ref get_nid_for_pfn(unsigned long pfn)
 396 {
 397         if (!pfn_valid_within(pfn))
 398                 return -1;
 399 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
 400         if (system_state < SYSTEM_RUNNING)
 401                 return early_pfn_to_nid(pfn);
 402 #endif
 403         return pfn_to_nid(pfn);
 404 }
 405
 406 /* register memory section under specified node if it spans that node */
 407 int register_mem_sect_under_node(struct memory_block *mem_blk, void *arg)
 408 {
 409         int ret, nid = *(int *)arg;
 410         unsigned long pfn, sect_start_pfn, sect_end_pfn;
 411
 412         mem_blk->nid = nid;
 413
 414         sect_start_pfn = section_nr_to_pfn(mem_blk->start_section_nr);
 415         sect_end_pfn = section_nr_to_pfn(mem_blk->end_section_nr);
 416         sect_end_pfn += PAGES_PER_SECTION - 1;
 417         for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
 418                 int page_nid;
 419
 420                 /*
 421                  * memory block could have several absent sections from start.
 422                  * skip pfn range from absent section
 423                  */
 424                 if (!pfn_present(pfn)) {
 425                         pfn = round_down(pfn + PAGES_PER_SECTION,
 426                                          PAGES_PER_SECTION) - 1;
 427                         continue;
 428                 }
 429
 430                 /*
 431                  * We need to check if page belongs to nid only for the boot
 432                  * case, during hotplug we know that all pages in the memory
 433                  * block belong to the same node.
 434                  */
 435                 if (system_state == SYSTEM_BOOTING) {
 436                         page_nid = get_nid_for_pfn(pfn);
 437                         if (page_nid < 0)
 438                                 continue;
 439                         if (page_nid != nid)
 440                                 continue;
 441                 }
 442                 ret = sysfs_create_link_nowarn(&node_devices[nid]->dev.kobj,
 443                                         &mem_blk->dev.kobj,
 444                                         kobject_name(&mem_blk->dev.kobj));
 445                 if (ret)
 446                         return ret;
 447
 448                 return sysfs_create_link_nowarn(&mem_blk->dev.kobj,
 449                                 &node_devices[nid]->dev.kobj,
 450                                 kobject_name(&node_devices[nid]->dev.kobj));
 451         }
 452         /* mem section does not span the specified node */
 453         return 0;
 454 }
 455
 456 /* unregister memory section under all nodes that it spans */
 457 int unregister_mem_sect_under_nodes(struct memory_block *mem_blk,
 458                                     unsigned long phys_index)
 459 {
 460         NODEMASK_ALLOC(nodemask_t, unlinked_nodes, GFP_KERNEL);
 461         unsigned long pfn, sect_start_pfn, sect_end_pfn;
 462
 463         if (!mem_blk) {
 464                 NODEMASK_FREE(unlinked_nodes);
 465                 return -EFAULT;
 466         }
 467         if (!unlinked_nodes)
 468                 return -ENOMEM;
 469         nodes_clear(*unlinked_nodes);
 470
 471         sect_start_pfn = section_nr_to_pfn(phys_index);
 472         sect_end_pfn = sect_start_pfn + PAGES_PER_SECTION - 1;
 473         for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
 474                 int nid;
 475
 476                 nid = get_nid_for_pfn(pfn);
 477                 if (nid < 0)
 478                         continue;
 479                 if (!node_online(nid))
 480                         continue;
 481                 if (node_test_and_set(nid, *unlinked_nodes))
 482                         continue;
 483                 sysfs_remove_link(&node_devices[nid]->dev.kobj,
 484                          kobject_name(&mem_blk->dev.kobj));
 485                 sysfs_remove_link(&mem_blk->dev.kobj,
 486                          kobject_name(&node_devices[nid]->dev.kobj));
 487         }
 488         NODEMASK_FREE(unlinked_nodes);
 489         return 0;
 490 }
 491
 492 int link_mem_sections(int nid, unsigned long start_pfn, unsigned long end_pfn)
 493 {
 494         return walk_memory_range(start_pfn, end_pfn, (void *)&nid,
 495                                         register_mem_sect_under_node);
 496 }
 497
 498 #ifdef CONFIG_HUGETLBFS
 499 /*
 500  * Handle per node hstate attribute [un]registration on transistions
 501  * to/from memoryless state.
 502  */
 503 static void node_hugetlb_work(struct work_struct *work)
 504 {
 505         struct node *node = container_of(work, struct node, node_work);
 506
 507         /*
 508          * We only get here when a node transitions to/from memoryless state.
 509          * We can detect which transition occurred by examining whether the
 510          * node has memory now.  hugetlb_register_node() already check this
 511          * so we try to register the attributes.  If that fails, then the
 512          * node has transitioned to memoryless, try to unregister the
 513          * attributes.
 514          */
 515         if (!hugetlb_register_node(node))
 516                 hugetlb_unregister_node(node);
 517 }
 518
 519 static void init_node_hugetlb_work(int nid)
 520 {
 521         INIT_WORK(&node_devices[nid]->node_work, node_hugetlb_work);
 522 }
 523
 524 static int node_memory_callback(struct notifier_block *self,
 525                                 unsigned long action, void *arg)
 526 {
 527         struct memory_notify *mnb = arg;
 528         int nid = mnb->status_change_nid;
 529
 530         switch (action) {
 531         case MEM_ONLINE:
 532         case MEM_OFFLINE:
 533                 /*
 534                  * offload per node hstate [un]registration to a work thread
 535                  * when transitioning to/from memoryless state.
 536                  */
 537                 if (nid != NUMA_NO_NODE)
 538                         schedule_work(&node_devices[nid]->node_work);
 539                 break;
 540
 541         case MEM_GOING_ONLINE:
 542         case MEM_GOING_OFFLINE:
 543         case MEM_CANCEL_ONLINE:
 544         case MEM_CANCEL_OFFLINE:
 545         default:
 546                 break;
 547         }
 548
 549         return NOTIFY_OK;
 550 }
 551 #endif  /* CONFIG_HUGETLBFS */
 552 #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
 553
 554 #if !defined(CONFIG_MEMORY_HOTPLUG_SPARSE) || \
 555     !defined(CONFIG_HUGETLBFS)
 556 static inline int node_memory_callback(struct notifier_block *self,
 557                                 unsigned long action, void *arg)
 558 {
 559         return NOTIFY_OK;
 560 }
 561
 562 static void init_node_hugetlb_work(int nid) { }
 563
 564 #endif
 565
 566 int __register_one_node(int nid)
 567 {
 568         int error;
 569         int cpu;
 570
 571         node_devices[nid] = kzalloc(sizeof(struct node), GFP_KERNEL);
 572         if (!node_devices[nid])
 573                 return -ENOMEM;
 574
 575         error = register_node(node_devices[nid], nid);
 576
 577         /* link cpu under this node */
 578         for_each_present_cpu(cpu) {
 579                 if (cpu_to_node(cpu) == nid)
 580                         register_cpu_under_node(cpu, nid);
 581         }
 582
 583         /* initialize work queue for memory hot plug */
 584         init_node_hugetlb_work(nid);
 585
 586         return error;
 587 }
 588
 589 void unregister_one_node(int nid)
 590 {
 591         if (!node_devices[nid])
 592                 return;
 593
 594         unregister_node(node_devices[nid]);
 595         node_devices[nid] = NULL;
 596 }
 597
 598 /*
 599  * node states attributes
 600  */
 601
 602 static ssize_t print_nodes_state(enum node_states state, char *buf)
 603 {
 604         int n;
 605
 606         n = scnprintf(buf, PAGE_SIZE - 1, "%*pbl",
 607                       nodemask_pr_args(&node_states[state]));
 608         buf[n++] = '\n';
 609         buf[n] = '\0';
 610         return n;
 611 }
 612
 613 struct node_attr {
 614         struct device_attribute attr;
 615         enum node_states state;
 616 };
 617
 618 static ssize_t show_node_state(struct device *dev,
 619                                struct device_attribute *attr, char *buf)
 620 {
 621         struct node_attr *na = container_of(attr, struct node_attr, attr);
 622         return print_nodes_state(na->state, buf);
 623 }
 624
 625 #define _NODE_ATTR(name, state) \
 626         { __ATTR(name, 0444, show_node_state, NULL), state }
 627
 628 static struct node_attr node_state_attr[] = {
 629         [N_POSSIBLE] = _NODE_ATTR(possible, N_POSSIBLE),
 630         [N_ONLINE] = _NODE_ATTR(online, N_ONLINE),
 631         [N_NORMAL_MEMORY] = _NODE_ATTR(has_normal_memory, N_NORMAL_MEMORY),
 632 #ifdef CONFIG_HIGHMEM
 633         [N_HIGH_MEMORY] = _NODE_ATTR(has_high_memory, N_HIGH_MEMORY),
 634 #endif
 635         [N_MEMORY] = _NODE_ATTR(has_memory, N_MEMORY),
 636         [N_CPU] = _NODE_ATTR(has_cpu, N_CPU),
 637 };
 638
 639 static struct attribute *node_state_attrs[] = {
 640         &node_state_attr[N_POSSIBLE].attr.attr,
 641         &node_state_attr[N_ONLINE].attr.attr,
 642         &node_state_attr[N_NORMAL_MEMORY].attr.attr,
 643 #ifdef CONFIG_HIGHMEM
 644         &node_state_attr[N_HIGH_MEMORY].attr.attr,
 645 #endif
 646         &node_state_attr[N_MEMORY].attr.attr,
 647         &node_state_attr[N_CPU].attr.attr,
 648         NULL
 649 };
 650
 651 static struct attribute_group memory_root_attr_group = {
 652         .attrs = node_state_attrs,
 653 };
 654
 655 static const struct attribute_group *cpu_root_attr_groups[] = {
 656         &memory_root_attr_group,
 657         NULL,
 658 };
 659
 660 #define NODE_CALLBACK_PRI       2       /* lower than SLAB */
 661 static int __init register_node_type(void)
 662 {
 663         int ret;
 664
 665         BUILD_BUG_ON(ARRAY_SIZE(node_state_attr) != NR_NODE_STATES);
 666         BUILD_BUG_ON(ARRAY_SIZE(node_state_attrs)-1 != NR_NODE_STATES);
 667
 668         ret = subsys_system_register(&node_subsys, cpu_root_attr_groups);
 669         if (!ret) {
 670                 static struct notifier_block node_memory_callback_nb = {
 671                         .notifier_call = node_memory_callback,
 672                         .priority = NODE_CALLBACK_PRI,
 673                 };
 674                 register_hotmemory_notifier(&node_memory_callback_nb);
 675         }
 676
 677         /*
 678          * Note:  we're not going to unregister the node class if we fail
 679          * to register the node state class attribute files.
 680          */
 681         return ret;
 682 }
 683 postcore_initcall(register_node_type);