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 22static struct bus_type node_subsys = { 23 .name = "node", 24 .dev_name = "node", 25}; 26 27 28static 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 39static 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} 44static 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 50static DEVICE_ATTR(cpumap, S_IRUGO, node_read_cpumask, NULL); 51static DEVICE_ATTR(cpulist, S_IRUGO, node_read_cpulist, NULL); 52 53#define K(x) ((x) << (PAGE_SHIFT - 10)) 54static 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 sysinfo i; 60 61 si_meminfo_node(&i, nid); 62 n = sprintf(buf, 63 "Node %d MemTotal: %8lu kB\n" 64 "Node %d MemFree: %8lu kB\n" 65 "Node %d MemUsed: %8lu kB\n" 66 "Node %d Active: %8lu kB\n" 67 "Node %d Inactive: %8lu kB\n" 68 "Node %d Active(anon): %8lu kB\n" 69 "Node %d Inactive(anon): %8lu kB\n" 70 "Node %d Active(file): %8lu kB\n" 71 "Node %d Inactive(file): %8lu kB\n" 72 "Node %d Unevictable: %8lu kB\n" 73 "Node %d Mlocked: %8lu kB\n", 74 nid, K(i.totalram), 75 nid, K(i.freeram), 76 nid, K(i.totalram - i.freeram), 77 nid, K(node_page_state(nid, NR_ACTIVE_ANON) + 78 node_page_state(nid, NR_ACTIVE_FILE)), 79 nid, K(node_page_state(nid, NR_INACTIVE_ANON) + 80 node_page_state(nid, NR_INACTIVE_FILE)), 81 nid, K(node_page_state(nid, NR_ACTIVE_ANON)), 82 nid, K(node_page_state(nid, NR_INACTIVE_ANON)), 83 nid, K(node_page_state(nid, NR_ACTIVE_FILE)), 84 nid, K(node_page_state(nid, NR_INACTIVE_FILE)), 85 nid, K(node_page_state(nid, NR_UNEVICTABLE)), 86 nid, K(node_page_state(nid, NR_MLOCK))); 87 88#ifdef CONFIG_HIGHMEM 89 n += sprintf(buf + n, 90 "Node %d HighTotal: %8lu kB\n" 91 "Node %d HighFree: %8lu kB\n" 92 "Node %d LowTotal: %8lu kB\n" 93 "Node %d LowFree: %8lu kB\n", 94 nid, K(i.totalhigh), 95 nid, K(i.freehigh), 96 nid, K(i.totalram - i.totalhigh), 97 nid, K(i.freeram - i.freehigh)); 98#endif 99 n += sprintf(buf + n, 100 "Node %d Dirty: %8lu kB\n" 101 "Node %d Writeback: %8lu kB\n" 102 "Node %d FilePages: %8lu kB\n" 103 "Node %d Mapped: %8lu kB\n" 104 "Node %d AnonPages: %8lu kB\n" 105 "Node %d Shmem: %8lu kB\n" 106 "Node %d KernelStack: %8lu kB\n" 107 "Node %d PageTables: %8lu kB\n" 108 "Node %d NFS_Unstable: %8lu kB\n" 109 "Node %d Bounce: %8lu kB\n" 110 "Node %d WritebackTmp: %8lu kB\n" 111 "Node %d Slab: %8lu kB\n" 112 "Node %d SReclaimable: %8lu kB\n" 113 "Node %d SUnreclaim: %8lu kB\n" 114#ifdef CONFIG_TRANSPARENT_HUGEPAGE 115 "Node %d AnonHugePages: %8lu kB\n" 116#endif 117 , 118 nid, K(node_page_state(nid, NR_FILE_DIRTY)), 119 nid, K(node_page_state(nid, NR_WRITEBACK)), 120 nid, K(node_page_state(nid, NR_FILE_PAGES)), 121 nid, K(node_page_state(nid, NR_FILE_MAPPED)), 122 nid, K(node_page_state(nid, NR_ANON_PAGES)), 123 nid, K(i.sharedram), 124 nid, node_page_state(nid, NR_KERNEL_STACK) * 125 THREAD_SIZE / 1024, 126 nid, K(node_page_state(nid, NR_PAGETABLE)), 127 nid, K(node_page_state(nid, NR_UNSTABLE_NFS)), 128 nid, K(node_page_state(nid, NR_BOUNCE)), 129 nid, K(node_page_state(nid, NR_WRITEBACK_TEMP)), 130 nid, K(node_page_state(nid, NR_SLAB_RECLAIMABLE) + 131 node_page_state(nid, NR_SLAB_UNRECLAIMABLE)), 132 nid, K(node_page_state(nid, NR_SLAB_RECLAIMABLE)), 133#ifdef CONFIG_TRANSPARENT_HUGEPAGE 134 nid, K(node_page_state(nid, NR_SLAB_UNRECLAIMABLE)) 135 , nid, 136 K(node_page_state(nid, NR_ANON_TRANSPARENT_HUGEPAGES) * 137 HPAGE_PMD_NR)); 138#else 139 nid, K(node_page_state(nid, NR_SLAB_UNRECLAIMABLE))); 140#endif 141 n += hugetlb_report_node_meminfo(nid, buf + n); 142 return n; 143} 144 145#undef K 146static DEVICE_ATTR(meminfo, S_IRUGO, node_read_meminfo, NULL); 147 148static ssize_t node_read_numastat(struct device *dev, 149 struct device_attribute *attr, char *buf) 150{ 151 return sprintf(buf, 152 "numa_hit %lu\n" 153 "numa_miss %lu\n" 154 "numa_foreign %lu\n" 155 "interleave_hit %lu\n" 156 "local_node %lu\n" 157 "other_node %lu\n", 158 node_page_state(dev->id, NUMA_HIT), 159 node_page_state(dev->id, NUMA_MISS), 160 node_page_state(dev->id, NUMA_FOREIGN), 161 node_page_state(dev->id, NUMA_INTERLEAVE_HIT), 162 node_page_state(dev->id, NUMA_LOCAL), 163 node_page_state(dev->id, NUMA_OTHER)); 164} 165static DEVICE_ATTR(numastat, S_IRUGO, node_read_numastat, NULL); 166 167static ssize_t node_read_vmstat(struct device *dev, 168 struct device_attribute *attr, char *buf) 169{ 170 int nid = dev->id; 171 int i; 172 int n = 0; 173 174 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) 175 n += sprintf(buf+n, "%s %lu\n", vmstat_text[i], 176 node_page_state(nid, i)); 177 178 return n; 179} 180static DEVICE_ATTR(vmstat, S_IRUGO, node_read_vmstat, NULL); 181 182static ssize_t node_read_distance(struct device *dev, 183 struct device_attribute *attr, char *buf) 184{ 185 int nid = dev->id; 186 int len = 0; 187 int i; 188 189 /* 190 * buf is currently PAGE_SIZE in length and each node needs 4 chars 191 * at the most (distance + space or newline). 192 */ 193 BUILD_BUG_ON(MAX_NUMNODES * 4 > PAGE_SIZE); 194 195 for_each_online_node(i) 196 len += sprintf(buf + len, "%s%d", i ? " " : "", node_distance(nid, i)); 197 198 len += sprintf(buf + len, "\n"); 199 return len; 200} 201static DEVICE_ATTR(distance, S_IRUGO, node_read_distance, NULL); 202 203static struct attribute *node_dev_attrs[] = { 204 &dev_attr_cpumap.attr, 205 &dev_attr_cpulist.attr, 206 &dev_attr_meminfo.attr, 207 &dev_attr_numastat.attr, 208 &dev_attr_distance.attr, 209 &dev_attr_vmstat.attr, 210 NULL 211}; 212ATTRIBUTE_GROUPS(node_dev); 213 214#ifdef CONFIG_HUGETLBFS 215/* 216 * hugetlbfs per node attributes registration interface: 217 * When/if hugetlb[fs] subsystem initializes [sometime after this module], 218 * it will register its per node attributes for all online nodes with 219 * memory. It will also call register_hugetlbfs_with_node(), below, to 220 * register its attribute registration functions with this node driver. 221 * Once these hooks have been initialized, the node driver will call into 222 * the hugetlb module to [un]register attributes for hot-plugged nodes. 223 */ 224static node_registration_func_t __hugetlb_register_node; 225static node_registration_func_t __hugetlb_unregister_node; 226 227static inline bool hugetlb_register_node(struct node *node) 228{ 229 if (__hugetlb_register_node && 230 node_state(node->dev.id, N_MEMORY)) { 231 __hugetlb_register_node(node); 232 return true; 233 } 234 return false; 235} 236 237static inline void hugetlb_unregister_node(struct node *node) 238{ 239 if (__hugetlb_unregister_node) 240 __hugetlb_unregister_node(node); 241} 242 243void register_hugetlbfs_with_node(node_registration_func_t doregister, 244 node_registration_func_t unregister) 245{ 246 __hugetlb_register_node = doregister; 247 __hugetlb_unregister_node = unregister; 248} 249#else 250static inline void hugetlb_register_node(struct node *node) {} 251 252static inline void hugetlb_unregister_node(struct node *node) {} 253#endif 254 255static void node_device_release(struct device *dev) 256{ 257 struct node *node = to_node(dev); 258 259#if defined(CONFIG_MEMORY_HOTPLUG_SPARSE) && defined(CONFIG_HUGETLBFS) 260 /* 261 * We schedule the work only when a memory section is 262 * onlined/offlined on this node. When we come here, 263 * all the memory on this node has been offlined, 264 * so we won't enqueue new work to this work. 265 * 266 * The work is using node->node_work, so we should 267 * flush work before freeing the memory. 268 */ 269 flush_work(&node->node_work); 270#endif 271 kfree(node); 272} 273 274/* 275 * register_node - Setup a sysfs device for a node. 276 * @num - Node number to use when creating the device. 277 * 278 * Initialize and register the node device. 279 */ 280static int register_node(struct node *node, int num, struct node *parent) 281{ 282 int error; 283 284 node->dev.id = num; 285 node->dev.bus = &node_subsys; 286 node->dev.release = node_device_release; 287 node->dev.groups = node_dev_groups; 288 error = device_register(&node->dev); 289 290 if (!error){ 291 hugetlb_register_node(node); 292 293 compaction_register_node(node); 294 } 295 return error; 296} 297 298/** 299 * unregister_node - unregister a node device 300 * @node: node going away 301 * 302 * Unregisters a node device @node. All the devices on the node must be 303 * unregistered before calling this function. 304 */ 305void unregister_node(struct node *node) 306{ 307 hugetlb_unregister_node(node); /* no-op, if memoryless node */ 308 309 device_unregister(&node->dev); 310} 311 312struct node *node_devices[MAX_NUMNODES]; 313 314/* 315 * register cpu under node 316 */ 317int register_cpu_under_node(unsigned int cpu, unsigned int nid) 318{ 319 int ret; 320 struct device *obj; 321 322 if (!node_online(nid)) 323 return 0; 324 325 obj = get_cpu_device(cpu); 326 if (!obj) 327 return 0; 328 329 ret = sysfs_create_link(&node_devices[nid]->dev.kobj, 330 &obj->kobj, 331 kobject_name(&obj->kobj)); 332 if (ret) 333 return ret; 334 335 return sysfs_create_link(&obj->kobj, 336 &node_devices[nid]->dev.kobj, 337 kobject_name(&node_devices[nid]->dev.kobj)); 338} 339 340int unregister_cpu_under_node(unsigned int cpu, unsigned int nid) 341{ 342 struct device *obj; 343 344 if (!node_online(nid)) 345 return 0; 346 347 obj = get_cpu_device(cpu); 348 if (!obj) 349 return 0; 350 351 sysfs_remove_link(&node_devices[nid]->dev.kobj, 352 kobject_name(&obj->kobj)); 353 sysfs_remove_link(&obj->kobj, 354 kobject_name(&node_devices[nid]->dev.kobj)); 355 356 return 0; 357} 358 359#ifdef CONFIG_MEMORY_HOTPLUG_SPARSE 360#define page_initialized(page) (page->lru.next) 361 362static int __init_refok get_nid_for_pfn(unsigned long pfn) 363{ 364 struct page *page; 365 366 if (!pfn_valid_within(pfn)) 367 return -1; 368#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT 369 if (system_state == SYSTEM_BOOTING) 370 return early_pfn_to_nid(pfn); 371#endif 372 page = pfn_to_page(pfn); 373 if (!page_initialized(page)) 374 return -1; 375 return pfn_to_nid(pfn); 376} 377 378/* register memory section under specified node if it spans that node */ 379int register_mem_sect_under_node(struct memory_block *mem_blk, int nid) 380{ 381 int ret; 382 unsigned long pfn, sect_start_pfn, sect_end_pfn; 383 384 if (!mem_blk) 385 return -EFAULT; 386 if (!node_online(nid)) 387 return 0; 388 389 sect_start_pfn = section_nr_to_pfn(mem_blk->start_section_nr); 390 sect_end_pfn = section_nr_to_pfn(mem_blk->end_section_nr); 391 sect_end_pfn += PAGES_PER_SECTION - 1; 392 for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) { 393 int page_nid; 394 395 /* 396 * memory block could have several absent sections from start. 397 * skip pfn range from absent section 398 */ 399 if (!pfn_present(pfn)) { 400 pfn = round_down(pfn + PAGES_PER_SECTION, 401 PAGES_PER_SECTION) - 1; 402 continue; 403 } 404 405 page_nid = get_nid_for_pfn(pfn); 406 if (page_nid < 0) 407 continue; 408 if (page_nid != nid) 409 continue; 410 ret = sysfs_create_link_nowarn(&node_devices[nid]->dev.kobj, 411 &mem_blk->dev.kobj, 412 kobject_name(&mem_blk->dev.kobj)); 413 if (ret) 414 return ret; 415 416 return sysfs_create_link_nowarn(&mem_blk->dev.kobj, 417 &node_devices[nid]->dev.kobj, 418 kobject_name(&node_devices[nid]->dev.kobj)); 419 } 420 /* mem section does not span the specified node */ 421 return 0; 422} 423 424/* unregister memory section under all nodes that it spans */ 425int unregister_mem_sect_under_nodes(struct memory_block *mem_blk, 426 unsigned long phys_index) 427{ 428 NODEMASK_ALLOC(nodemask_t, unlinked_nodes, GFP_KERNEL); 429 unsigned long pfn, sect_start_pfn, sect_end_pfn; 430 431 if (!mem_blk) { 432 NODEMASK_FREE(unlinked_nodes); 433 return -EFAULT; 434 } 435 if (!unlinked_nodes) 436 return -ENOMEM; 437 nodes_clear(*unlinked_nodes); 438 439 sect_start_pfn = section_nr_to_pfn(phys_index); 440 sect_end_pfn = sect_start_pfn + PAGES_PER_SECTION - 1; 441 for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) { 442 int nid; 443 444 nid = get_nid_for_pfn(pfn); 445 if (nid < 0) 446 continue; 447 if (!node_online(nid)) 448 continue; 449 if (node_test_and_set(nid, *unlinked_nodes)) 450 continue; 451 sysfs_remove_link(&node_devices[nid]->dev.kobj, 452 kobject_name(&mem_blk->dev.kobj)); 453 sysfs_remove_link(&mem_blk->dev.kobj, 454 kobject_name(&node_devices[nid]->dev.kobj)); 455 } 456 NODEMASK_FREE(unlinked_nodes); 457 return 0; 458} 459 460static int link_mem_sections(int nid) 461{ 462 unsigned long start_pfn = NODE_DATA(nid)->node_start_pfn; 463 unsigned long end_pfn = start_pfn + NODE_DATA(nid)->node_spanned_pages; 464 unsigned long pfn; 465 struct memory_block *mem_blk = NULL; 466 int err = 0; 467 468 for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) { 469 unsigned long section_nr = pfn_to_section_nr(pfn); 470 struct mem_section *mem_sect; 471 int ret; 472 473 if (!present_section_nr(section_nr)) 474 continue; 475 mem_sect = __nr_to_section(section_nr); 476 477 /* same memblock ? */ 478 if (mem_blk) 479 if ((section_nr >= mem_blk->start_section_nr) && 480 (section_nr <= mem_blk->end_section_nr)) 481 continue; 482 483 mem_blk = find_memory_block_hinted(mem_sect, mem_blk); 484 485 ret = register_mem_sect_under_node(mem_blk, nid); 486 if (!err) 487 err = ret; 488 489 /* discard ref obtained in find_memory_block() */ 490 } 491 492 if (mem_blk) 493 kobject_put(&mem_blk->dev.kobj); 494 return err; 495} 496 497#ifdef CONFIG_HUGETLBFS 498/* 499 * Handle per node hstate attribute [un]registration on transistions 500 * to/from memoryless state. 501 */ 502static void node_hugetlb_work(struct work_struct *work) 503{ 504 struct node *node = container_of(work, struct node, node_work); 505 506 /* 507 * We only get here when a node transitions to/from memoryless state. 508 * We can detect which transition occurred by examining whether the 509 * node has memory now. hugetlb_register_node() already check this 510 * so we try to register the attributes. If that fails, then the 511 * node has transitioned to memoryless, try to unregister the 512 * attributes. 513 */ 514 if (!hugetlb_register_node(node)) 515 hugetlb_unregister_node(node); 516} 517 518static void init_node_hugetlb_work(int nid) 519{ 520 INIT_WORK(&node_devices[nid]->node_work, node_hugetlb_work); 521} 522 523static int node_memory_callback(struct notifier_block *self, 524 unsigned long action, void *arg) 525{ 526 struct memory_notify *mnb = arg; 527 int nid = mnb->status_change_nid; 528 529 switch (action) { 530 case MEM_ONLINE: 531 case MEM_OFFLINE: 532 /* 533 * offload per node hstate [un]registration to a work thread 534 * when transitioning to/from memoryless state. 535 */ 536 if (nid != NUMA_NO_NODE) 537 schedule_work(&node_devices[nid]->node_work); 538 break; 539 540 case MEM_GOING_ONLINE: 541 case MEM_GOING_OFFLINE: 542 case MEM_CANCEL_ONLINE: 543 case MEM_CANCEL_OFFLINE: 544 default: 545 break; 546 } 547 548 return NOTIFY_OK; 549} 550#endif /* CONFIG_HUGETLBFS */ 551#else /* !CONFIG_MEMORY_HOTPLUG_SPARSE */ 552 553static int link_mem_sections(int nid) { return 0; } 554#endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */ 555 556#if !defined(CONFIG_MEMORY_HOTPLUG_SPARSE) || \ 557 !defined(CONFIG_HUGETLBFS) 558static inline int node_memory_callback(struct notifier_block *self, 559 unsigned long action, void *arg) 560{ 561 return NOTIFY_OK; 562} 563 564static void init_node_hugetlb_work(int nid) { } 565 566#endif 567 568int register_one_node(int nid) 569{ 570 int error = 0; 571 int cpu; 572 573 if (node_online(nid)) { 574 int p_node = parent_node(nid); 575 struct node *parent = NULL; 576 577 if (p_node != nid) 578 parent = node_devices[p_node]; 579 580 node_devices[nid] = kzalloc(sizeof(struct node), GFP_KERNEL); 581 if (!node_devices[nid]) 582 return -ENOMEM; 583 584 error = register_node(node_devices[nid], nid, parent); 585 586 /* link cpu under this node */ 587 for_each_present_cpu(cpu) { 588 if (cpu_to_node(cpu) == nid) 589 register_cpu_under_node(cpu, nid); 590 } 591 592 /* link memory sections under this node */ 593 error = link_mem_sections(nid); 594 595 /* initialize work queue for memory hot plug */ 596 init_node_hugetlb_work(nid); 597 } 598 599 return error; 600 601} 602 603void unregister_one_node(int nid) 604{ 605 if (!node_devices[nid]) 606 return; 607 608 unregister_node(node_devices[nid]); 609 node_devices[nid] = NULL; 610} 611 612/* 613 * node states attributes 614 */ 615 616static ssize_t print_nodes_state(enum node_states state, char *buf) 617{ 618 int n; 619 620 n = scnprintf(buf, PAGE_SIZE - 1, "%*pbl", 621 nodemask_pr_args(&node_states[state])); 622 buf[n++] = '\n'; 623 buf[n] = '\0'; 624 return n; 625} 626 627struct node_attr { 628 struct device_attribute attr; 629 enum node_states state; 630}; 631 632static ssize_t show_node_state(struct device *dev, 633 struct device_attribute *attr, char *buf) 634{ 635 struct node_attr *na = container_of(attr, struct node_attr, attr); 636 return print_nodes_state(na->state, buf); 637} 638 639#define _NODE_ATTR(name, state) \ 640 { __ATTR(name, 0444, show_node_state, NULL), state } 641 642static struct node_attr node_state_attr[] = { 643 [N_POSSIBLE] = _NODE_ATTR(possible, N_POSSIBLE), 644 [N_ONLINE] = _NODE_ATTR(online, N_ONLINE), 645 [N_NORMAL_MEMORY] = _NODE_ATTR(has_normal_memory, N_NORMAL_MEMORY), 646#ifdef CONFIG_HIGHMEM 647 [N_HIGH_MEMORY] = _NODE_ATTR(has_high_memory, N_HIGH_MEMORY), 648#endif 649#ifdef CONFIG_MOVABLE_NODE 650 [N_MEMORY] = _NODE_ATTR(has_memory, N_MEMORY), 651#endif 652 [N_CPU] = _NODE_ATTR(has_cpu, N_CPU), 653}; 654 655static struct attribute *node_state_attrs[] = { 656 &node_state_attr[N_POSSIBLE].attr.attr, 657 &node_state_attr[N_ONLINE].attr.attr, 658 &node_state_attr[N_NORMAL_MEMORY].attr.attr, 659#ifdef CONFIG_HIGHMEM 660 &node_state_attr[N_HIGH_MEMORY].attr.attr, 661#endif 662#ifdef CONFIG_MOVABLE_NODE 663 &node_state_attr[N_MEMORY].attr.attr, 664#endif 665 &node_state_attr[N_CPU].attr.attr, 666 NULL 667}; 668 669static struct attribute_group memory_root_attr_group = { 670 .attrs = node_state_attrs, 671}; 672 673static 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 */ 679static 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} 701postcore_initcall(register_node_type); 702