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, int type, char *buf) 29{ 30 struct node *node_dev = to_node(dev); 31 const struct cpumask *mask = cpumask_of_node(node_dev->dev.id); 32 int len; 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 len = type? 38 cpulist_scnprintf(buf, PAGE_SIZE-2, mask) : 39 cpumask_scnprintf(buf, PAGE_SIZE-2, mask); 40 buf[len++] = '\n'; 41 buf[len] = '\0'; 42 return len; 43} 44 45static inline ssize_t node_read_cpumask(struct device *dev, 46 struct device_attribute *attr, char *buf) 47{ 48 return node_read_cpumap(dev, 0, buf); 49} 50static inline ssize_t node_read_cpulist(struct device *dev, 51 struct device_attribute *attr, char *buf) 52{ 53 return node_read_cpumap(dev, 1, buf); 54} 55 56static DEVICE_ATTR(cpumap, S_IRUGO, node_read_cpumask, NULL); 57static DEVICE_ATTR(cpulist, S_IRUGO, node_read_cpulist, NULL); 58 59#define K(x) ((x) << (PAGE_SHIFT - 10)) 60static ssize_t node_read_meminfo(struct device *dev, 61 struct device_attribute *attr, char *buf) 62{ 63 int n; 64 int nid = dev->id; 65 struct sysinfo i; 66 67 si_meminfo_node(&i, nid); 68 n = sprintf(buf, 69 "Node %d MemTotal: %8lu kB\n" 70 "Node %d MemFree: %8lu kB\n" 71 "Node %d MemUsed: %8lu kB\n" 72 "Node %d Active: %8lu kB\n" 73 "Node %d Inactive: %8lu kB\n" 74 "Node %d Active(anon): %8lu kB\n" 75 "Node %d Inactive(anon): %8lu kB\n" 76 "Node %d Active(file): %8lu kB\n" 77 "Node %d Inactive(file): %8lu kB\n" 78 "Node %d Unevictable: %8lu kB\n" 79 "Node %d Mlocked: %8lu kB\n", 80 nid, K(i.totalram), 81 nid, K(i.freeram), 82 nid, K(i.totalram - i.freeram), 83 nid, K(node_page_state(nid, NR_ACTIVE_ANON) + 84 node_page_state(nid, NR_ACTIVE_FILE)), 85 nid, K(node_page_state(nid, NR_INACTIVE_ANON) + 86 node_page_state(nid, NR_INACTIVE_FILE)), 87 nid, K(node_page_state(nid, NR_ACTIVE_ANON)), 88 nid, K(node_page_state(nid, NR_INACTIVE_ANON)), 89 nid, K(node_page_state(nid, NR_ACTIVE_FILE)), 90 nid, K(node_page_state(nid, NR_INACTIVE_FILE)), 91 nid, K(node_page_state(nid, NR_UNEVICTABLE)), 92 nid, K(node_page_state(nid, NR_MLOCK))); 93 94#ifdef CONFIG_HIGHMEM 95 n += sprintf(buf + n, 96 "Node %d HighTotal: %8lu kB\n" 97 "Node %d HighFree: %8lu kB\n" 98 "Node %d LowTotal: %8lu kB\n" 99 "Node %d LowFree: %8lu kB\n", 100 nid, K(i.totalhigh), 101 nid, K(i.freehigh), 102 nid, K(i.totalram - i.totalhigh), 103 nid, K(i.freeram - i.freehigh)); 104#endif 105 n += sprintf(buf + n, 106 "Node %d Dirty: %8lu kB\n" 107 "Node %d Writeback: %8lu kB\n" 108 "Node %d FilePages: %8lu kB\n" 109 "Node %d Mapped: %8lu kB\n" 110 "Node %d AnonPages: %8lu kB\n" 111 "Node %d Shmem: %8lu kB\n" 112 "Node %d KernelStack: %8lu kB\n" 113 "Node %d PageTables: %8lu kB\n" 114 "Node %d NFS_Unstable: %8lu kB\n" 115 "Node %d Bounce: %8lu kB\n" 116 "Node %d WritebackTmp: %8lu kB\n" 117 "Node %d Slab: %8lu kB\n" 118 "Node %d SReclaimable: %8lu kB\n" 119 "Node %d SUnreclaim: %8lu kB\n" 120#ifdef CONFIG_TRANSPARENT_HUGEPAGE 121 "Node %d AnonHugePages: %8lu kB\n" 122#endif 123 , 124 nid, K(node_page_state(nid, NR_FILE_DIRTY)), 125 nid, K(node_page_state(nid, NR_WRITEBACK)), 126 nid, K(node_page_state(nid, NR_FILE_PAGES)), 127 nid, K(node_page_state(nid, NR_FILE_MAPPED)), 128 nid, K(node_page_state(nid, NR_ANON_PAGES)), 129 nid, K(i.sharedram), 130 nid, node_page_state(nid, NR_KERNEL_STACK) * 131 THREAD_SIZE / 1024, 132 nid, K(node_page_state(nid, NR_PAGETABLE)), 133 nid, K(node_page_state(nid, NR_UNSTABLE_NFS)), 134 nid, K(node_page_state(nid, NR_BOUNCE)), 135 nid, K(node_page_state(nid, NR_WRITEBACK_TEMP)), 136 nid, K(node_page_state(nid, NR_SLAB_RECLAIMABLE) + 137 node_page_state(nid, NR_SLAB_UNRECLAIMABLE)), 138 nid, K(node_page_state(nid, NR_SLAB_RECLAIMABLE)), 139#ifdef CONFIG_TRANSPARENT_HUGEPAGE 140 nid, K(node_page_state(nid, NR_SLAB_UNRECLAIMABLE)) 141 , nid, 142 K(node_page_state(nid, NR_ANON_TRANSPARENT_HUGEPAGES) * 143 HPAGE_PMD_NR)); 144#else 145 nid, K(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 152static DEVICE_ATTR(meminfo, S_IRUGO, node_read_meminfo, NULL); 153 154static 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 node_page_state(dev->id, NUMA_HIT), 165 node_page_state(dev->id, NUMA_MISS), 166 node_page_state(dev->id, NUMA_FOREIGN), 167 node_page_state(dev->id, NUMA_INTERLEAVE_HIT), 168 node_page_state(dev->id, NUMA_LOCAL), 169 node_page_state(dev->id, NUMA_OTHER)); 170} 171static DEVICE_ATTR(numastat, S_IRUGO, node_read_numastat, NULL); 172 173static ssize_t node_read_vmstat(struct device *dev, 174 struct device_attribute *attr, char *buf) 175{ 176 int nid = dev->id; 177 int i; 178 int n = 0; 179 180 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) 181 n += sprintf(buf+n, "%s %lu\n", vmstat_text[i], 182 node_page_state(nid, i)); 183 184 return n; 185} 186static DEVICE_ATTR(vmstat, S_IRUGO, node_read_vmstat, NULL); 187 188static ssize_t node_read_distance(struct device *dev, 189 struct device_attribute *attr, char * buf) 190{ 191 int nid = dev->id; 192 int len = 0; 193 int i; 194 195 /* 196 * buf is currently PAGE_SIZE in length and each node needs 4 chars 197 * at the most (distance + space or newline). 198 */ 199 BUILD_BUG_ON(MAX_NUMNODES * 4 > PAGE_SIZE); 200 201 for_each_online_node(i) 202 len += sprintf(buf + len, "%s%d", i ? " " : "", node_distance(nid, i)); 203 204 len += sprintf(buf + len, "\n"); 205 return len; 206} 207static DEVICE_ATTR(distance, S_IRUGO, node_read_distance, NULL); 208 209#ifdef CONFIG_HUGETLBFS 210/* 211 * hugetlbfs per node attributes registration interface: 212 * When/if hugetlb[fs] subsystem initializes [sometime after this module], 213 * it will register its per node attributes for all online nodes with 214 * memory. It will also call register_hugetlbfs_with_node(), below, to 215 * register its attribute registration functions with this node driver. 216 * Once these hooks have been initialized, the node driver will call into 217 * the hugetlb module to [un]register attributes for hot-plugged nodes. 218 */ 219static node_registration_func_t __hugetlb_register_node; 220static node_registration_func_t __hugetlb_unregister_node; 221 222static inline bool hugetlb_register_node(struct node *node) 223{ 224 if (__hugetlb_register_node && 225 node_state(node->dev.id, N_MEMORY)) { 226 __hugetlb_register_node(node); 227 return true; 228 } 229 return false; 230} 231 232static inline void hugetlb_unregister_node(struct node *node) 233{ 234 if (__hugetlb_unregister_node) 235 __hugetlb_unregister_node(node); 236} 237 238void register_hugetlbfs_with_node(node_registration_func_t doregister, 239 node_registration_func_t unregister) 240{ 241 __hugetlb_register_node = doregister; 242 __hugetlb_unregister_node = unregister; 243} 244#else 245static inline void hugetlb_register_node(struct node *node) {} 246 247static inline void hugetlb_unregister_node(struct node *node) {} 248#endif 249 250static void node_device_release(struct device *dev) 251{ 252 struct node *node = to_node(dev); 253 254#if defined(CONFIG_MEMORY_HOTPLUG_SPARSE) && defined(CONFIG_HUGETLBFS) 255 /* 256 * We schedule the work only when a memory section is 257 * onlined/offlined on this node. When we come here, 258 * all the memory on this node has been offlined, 259 * so we won't enqueue new work to this work. 260 * 261 * The work is using node->node_work, so we should 262 * flush work before freeing the memory. 263 */ 264 flush_work(&node->node_work); 265#endif 266 kfree(node); 267} 268 269/* 270 * register_node - Setup a sysfs device for a node. 271 * @num - Node number to use when creating the device. 272 * 273 * Initialize and register the node device. 274 */ 275static int register_node(struct node *node, int num, struct node *parent) 276{ 277 int error; 278 279 node->dev.id = num; 280 node->dev.bus = &node_subsys; 281 node->dev.release = node_device_release; 282 error = device_register(&node->dev); 283 284 if (!error){ 285 device_create_file(&node->dev, &dev_attr_cpumap); 286 device_create_file(&node->dev, &dev_attr_cpulist); 287 device_create_file(&node->dev, &dev_attr_meminfo); 288 device_create_file(&node->dev, &dev_attr_numastat); 289 device_create_file(&node->dev, &dev_attr_distance); 290 device_create_file(&node->dev, &dev_attr_vmstat); 291 292 hugetlb_register_node(node); 293 294 compaction_register_node(node); 295 } 296 return error; 297} 298 299/** 300 * unregister_node - unregister a node device 301 * @node: node going away 302 * 303 * Unregisters a node device @node. All the devices on the node must be 304 * unregistered before calling this function. 305 */ 306void unregister_node(struct node *node) 307{ 308 device_remove_file(&node->dev, &dev_attr_cpumap); 309 device_remove_file(&node->dev, &dev_attr_cpulist); 310 device_remove_file(&node->dev, &dev_attr_meminfo); 311 device_remove_file(&node->dev, &dev_attr_numastat); 312 device_remove_file(&node->dev, &dev_attr_distance); 313 device_remove_file(&node->dev, &dev_attr_vmstat); 314 315 hugetlb_unregister_node(node); /* no-op, if memoryless node */ 316 317 device_unregister(&node->dev); 318} 319 320struct node *node_devices[MAX_NUMNODES]; 321 322/* 323 * register cpu under node 324 */ 325int register_cpu_under_node(unsigned int cpu, unsigned int nid) 326{ 327 int ret; 328 struct device *obj; 329 330 if (!node_online(nid)) 331 return 0; 332 333 obj = get_cpu_device(cpu); 334 if (!obj) 335 return 0; 336 337 ret = sysfs_create_link(&node_devices[nid]->dev.kobj, 338 &obj->kobj, 339 kobject_name(&obj->kobj)); 340 if (ret) 341 return ret; 342 343 return sysfs_create_link(&obj->kobj, 344 &node_devices[nid]->dev.kobj, 345 kobject_name(&node_devices[nid]->dev.kobj)); 346} 347 348int unregister_cpu_under_node(unsigned int cpu, unsigned int nid) 349{ 350 struct device *obj; 351 352 if (!node_online(nid)) 353 return 0; 354 355 obj = get_cpu_device(cpu); 356 if (!obj) 357 return 0; 358 359 sysfs_remove_link(&node_devices[nid]->dev.kobj, 360 kobject_name(&obj->kobj)); 361 sysfs_remove_link(&obj->kobj, 362 kobject_name(&node_devices[nid]->dev.kobj)); 363 364 return 0; 365} 366 367#ifdef CONFIG_MEMORY_HOTPLUG_SPARSE 368#define page_initialized(page) (page->lru.next) 369 370static int get_nid_for_pfn(unsigned long pfn) 371{ 372 struct page *page; 373 374 if (!pfn_valid_within(pfn)) 375 return -1; 376 page = pfn_to_page(pfn); 377 if (!page_initialized(page)) 378 return -1; 379 return pfn_to_nid(pfn); 380} 381 382/* register memory section under specified node if it spans that node */ 383int register_mem_sect_under_node(struct memory_block *mem_blk, int nid) 384{ 385 int ret; 386 unsigned long pfn, sect_start_pfn, sect_end_pfn; 387 388 if (!mem_blk) 389 return -EFAULT; 390 if (!node_online(nid)) 391 return 0; 392 393 sect_start_pfn = section_nr_to_pfn(mem_blk->start_section_nr); 394 sect_end_pfn = section_nr_to_pfn(mem_blk->end_section_nr); 395 sect_end_pfn += PAGES_PER_SECTION - 1; 396 for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) { 397 int page_nid; 398 399 page_nid = get_nid_for_pfn(pfn); 400 if (page_nid < 0) 401 continue; 402 if (page_nid != nid) 403 continue; 404 ret = sysfs_create_link_nowarn(&node_devices[nid]->dev.kobj, 405 &mem_blk->dev.kobj, 406 kobject_name(&mem_blk->dev.kobj)); 407 if (ret) 408 return ret; 409 410 return sysfs_create_link_nowarn(&mem_blk->dev.kobj, 411 &node_devices[nid]->dev.kobj, 412 kobject_name(&node_devices[nid]->dev.kobj)); 413 } 414 /* mem section does not span the specified node */ 415 return 0; 416} 417 418/* unregister memory section under all nodes that it spans */ 419int unregister_mem_sect_under_nodes(struct memory_block *mem_blk, 420 unsigned long phys_index) 421{ 422 NODEMASK_ALLOC(nodemask_t, unlinked_nodes, GFP_KERNEL); 423 unsigned long pfn, sect_start_pfn, sect_end_pfn; 424 425 if (!mem_blk) { 426 NODEMASK_FREE(unlinked_nodes); 427 return -EFAULT; 428 } 429 if (!unlinked_nodes) 430 return -ENOMEM; 431 nodes_clear(*unlinked_nodes); 432 433 sect_start_pfn = section_nr_to_pfn(phys_index); 434 sect_end_pfn = sect_start_pfn + PAGES_PER_SECTION - 1; 435 for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) { 436 int nid; 437 438 nid = get_nid_for_pfn(pfn); 439 if (nid < 0) 440 continue; 441 if (!node_online(nid)) 442 continue; 443 if (node_test_and_set(nid, *unlinked_nodes)) 444 continue; 445 sysfs_remove_link(&node_devices[nid]->dev.kobj, 446 kobject_name(&mem_blk->dev.kobj)); 447 sysfs_remove_link(&mem_blk->dev.kobj, 448 kobject_name(&node_devices[nid]->dev.kobj)); 449 } 450 NODEMASK_FREE(unlinked_nodes); 451 return 0; 452} 453 454static int link_mem_sections(int nid) 455{ 456 unsigned long start_pfn = NODE_DATA(nid)->node_start_pfn; 457 unsigned long end_pfn = start_pfn + NODE_DATA(nid)->node_spanned_pages; 458 unsigned long pfn; 459 struct memory_block *mem_blk = NULL; 460 int err = 0; 461 462 for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) { 463 unsigned long section_nr = pfn_to_section_nr(pfn); 464 struct mem_section *mem_sect; 465 int ret; 466 467 if (!present_section_nr(section_nr)) 468 continue; 469 mem_sect = __nr_to_section(section_nr); 470 471 /* same memblock ? */ 472 if (mem_blk) 473 if ((section_nr >= mem_blk->start_section_nr) && 474 (section_nr <= mem_blk->end_section_nr)) 475 continue; 476 477 mem_blk = find_memory_block_hinted(mem_sect, mem_blk); 478 479 ret = register_mem_sect_under_node(mem_blk, nid); 480 if (!err) 481 err = ret; 482 483 /* discard ref obtained in find_memory_block() */ 484 } 485 486 if (mem_blk) 487 kobject_put(&mem_blk->dev.kobj); 488 return err; 489} 490 491#ifdef CONFIG_HUGETLBFS 492/* 493 * Handle per node hstate attribute [un]registration on transistions 494 * to/from memoryless state. 495 */ 496static void node_hugetlb_work(struct work_struct *work) 497{ 498 struct node *node = container_of(work, struct node, node_work); 499 500 /* 501 * We only get here when a node transitions to/from memoryless state. 502 * We can detect which transition occurred by examining whether the 503 * node has memory now. hugetlb_register_node() already check this 504 * so we try to register the attributes. If that fails, then the 505 * node has transitioned to memoryless, try to unregister the 506 * attributes. 507 */ 508 if (!hugetlb_register_node(node)) 509 hugetlb_unregister_node(node); 510} 511 512static void init_node_hugetlb_work(int nid) 513{ 514 INIT_WORK(&node_devices[nid]->node_work, node_hugetlb_work); 515} 516 517static int node_memory_callback(struct notifier_block *self, 518 unsigned long action, void *arg) 519{ 520 struct memory_notify *mnb = arg; 521 int nid = mnb->status_change_nid; 522 523 switch (action) { 524 case MEM_ONLINE: 525 case MEM_OFFLINE: 526 /* 527 * offload per node hstate [un]registration to a work thread 528 * when transitioning to/from memoryless state. 529 */ 530 if (nid != NUMA_NO_NODE) 531 schedule_work(&node_devices[nid]->node_work); 532 break; 533 534 case MEM_GOING_ONLINE: 535 case MEM_GOING_OFFLINE: 536 case MEM_CANCEL_ONLINE: 537 case MEM_CANCEL_OFFLINE: 538 default: 539 break; 540 } 541 542 return NOTIFY_OK; 543} 544#endif /* CONFIG_HUGETLBFS */ 545#else /* !CONFIG_MEMORY_HOTPLUG_SPARSE */ 546 547static int link_mem_sections(int nid) { return 0; } 548#endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */ 549 550#if !defined(CONFIG_MEMORY_HOTPLUG_SPARSE) || \ 551 !defined(CONFIG_HUGETLBFS) 552static inline int node_memory_callback(struct notifier_block *self, 553 unsigned long action, void *arg) 554{ 555 return NOTIFY_OK; 556} 557 558static void init_node_hugetlb_work(int nid) { } 559 560#endif 561 562int register_one_node(int nid) 563{ 564 int error = 0; 565 int cpu; 566 567 if (node_online(nid)) { 568 int p_node = parent_node(nid); 569 struct node *parent = NULL; 570 571 if (p_node != nid) 572 parent = node_devices[p_node]; 573 574 node_devices[nid] = kzalloc(sizeof(struct node), GFP_KERNEL); 575 if (!node_devices[nid]) 576 return -ENOMEM; 577 578 error = register_node(node_devices[nid], nid, parent); 579 580 /* link cpu under this node */ 581 for_each_present_cpu(cpu) { 582 if (cpu_to_node(cpu) == nid) 583 register_cpu_under_node(cpu, nid); 584 } 585 586 /* link memory sections under this node */ 587 error = link_mem_sections(nid); 588 589 /* initialize work queue for memory hot plug */ 590 init_node_hugetlb_work(nid); 591 } 592 593 return error; 594 595} 596 597void unregister_one_node(int nid) 598{ 599 if (!node_devices[nid]) 600 return; 601 602 unregister_node(node_devices[nid]); 603 node_devices[nid] = NULL; 604} 605 606/* 607 * node states attributes 608 */ 609 610static ssize_t print_nodes_state(enum node_states state, char *buf) 611{ 612 int n; 613 614 n = nodelist_scnprintf(buf, PAGE_SIZE-2, node_states[state]); 615 buf[n++] = '\n'; 616 buf[n] = '\0'; 617 return n; 618} 619 620struct node_attr { 621 struct device_attribute attr; 622 enum node_states state; 623}; 624 625static ssize_t show_node_state(struct device *dev, 626 struct device_attribute *attr, char *buf) 627{ 628 struct node_attr *na = container_of(attr, struct node_attr, attr); 629 return print_nodes_state(na->state, buf); 630} 631 632#define _NODE_ATTR(name, state) \ 633 { __ATTR(name, 0444, show_node_state, NULL), state } 634 635static struct node_attr node_state_attr[] = { 636 [N_POSSIBLE] = _NODE_ATTR(possible, N_POSSIBLE), 637 [N_ONLINE] = _NODE_ATTR(online, N_ONLINE), 638 [N_NORMAL_MEMORY] = _NODE_ATTR(has_normal_memory, N_NORMAL_MEMORY), 639#ifdef CONFIG_HIGHMEM 640 [N_HIGH_MEMORY] = _NODE_ATTR(has_high_memory, N_HIGH_MEMORY), 641#endif 642#ifdef CONFIG_MOVABLE_NODE 643 [N_MEMORY] = _NODE_ATTR(has_memory, N_MEMORY), 644#endif 645 [N_CPU] = _NODE_ATTR(has_cpu, N_CPU), 646}; 647 648static struct attribute *node_state_attrs[] = { 649 &node_state_attr[N_POSSIBLE].attr.attr, 650 &node_state_attr[N_ONLINE].attr.attr, 651 &node_state_attr[N_NORMAL_MEMORY].attr.attr, 652#ifdef CONFIG_HIGHMEM 653 &node_state_attr[N_HIGH_MEMORY].attr.attr, 654#endif 655#ifdef CONFIG_MOVABLE_NODE 656 &node_state_attr[N_MEMORY].attr.attr, 657#endif 658 &node_state_attr[N_CPU].attr.attr, 659 NULL 660}; 661 662static struct attribute_group memory_root_attr_group = { 663 .attrs = node_state_attrs, 664}; 665 666static const struct attribute_group *cpu_root_attr_groups[] = { 667 &memory_root_attr_group, 668 NULL, 669}; 670 671#define NODE_CALLBACK_PRI 2 /* lower than SLAB */ 672static int __init register_node_type(void) 673{ 674 int ret; 675 676 BUILD_BUG_ON(ARRAY_SIZE(node_state_attr) != NR_NODE_STATES); 677 BUILD_BUG_ON(ARRAY_SIZE(node_state_attrs)-1 != NR_NODE_STATES); 678 679 ret = subsys_system_register(&node_subsys, cpu_root_attr_groups); 680 if (!ret) { 681 static struct notifier_block node_memory_callback_nb = { 682 .notifier_call = node_memory_callback, 683 .priority = NODE_CALLBACK_PRI, 684 }; 685 register_hotmemory_notifier(&node_memory_callback_nb); 686 } 687 688 /* 689 * Note: we're not going to unregister the node class if we fail 690 * to register the node state class attribute files. 691 */ 692 return ret; 693} 694postcore_initcall(register_node_type); 695