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 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 146 static DEVICE_ATTR(meminfo, S_IRUGO, node_read_meminfo, NULL); 147 148 static 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 } 165 static DEVICE_ATTR(numastat, S_IRUGO, node_read_numastat, NULL); 166 167 static 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 } 180 static DEVICE_ATTR(vmstat, S_IRUGO, node_read_vmstat, NULL); 181 182 static 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 } 201 static DEVICE_ATTR(distance, S_IRUGO, node_read_distance, NULL); 202 203 static 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 }; 212 ATTRIBUTE_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 */ 224 static node_registration_func_t __hugetlb_register_node; 225 static node_registration_func_t __hugetlb_unregister_node; 226 227 static 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 } 236 237 static inline void hugetlb_unregister_node(struct node *node) 238 { 239 if (__hugetlb_unregister_node) 240 __hugetlb_unregister_node(node); 241 } 242 243 void 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 250 static inline void hugetlb_register_node(struct node *node) {} 251 252 static inline void hugetlb_unregister_node(struct node *node) {} 253 #endif 254 255 static 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 */ 280 static 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 */ 305 void unregister_node(struct node *node) 306 { 307 hugetlb_unregister_node(node); /* no-op, if memoryless node */ 308 309 device_unregister(&node->dev); 310 } 311 312 struct node *node_devices[MAX_NUMNODES]; 313 314 /* 315 * register cpu under node 316 */ 317 int 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 } 339 340 int 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) 361 362 static 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 */ 379 int 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 page_nid = get_nid_for_pfn(pfn); 396 if (page_nid < 0) 397 continue; 398 if (page_nid != nid) 399 continue; 400 ret = sysfs_create_link_nowarn(&node_devices[nid]->dev.kobj, 401 &mem_blk->dev.kobj, 402 kobject_name(&mem_blk->dev.kobj)); 403 if (ret) 404 return ret; 405 406 return sysfs_create_link_nowarn(&mem_blk->dev.kobj, 407 &node_devices[nid]->dev.kobj, 408 kobject_name(&node_devices[nid]->dev.kobj)); 409 } 410 /* mem section does not span the specified node */ 411 return 0; 412 } 413 414 /* unregister memory section under all nodes that it spans */ 415 int unregister_mem_sect_under_nodes(struct memory_block *mem_blk, 416 unsigned long phys_index) 417 { 418 NODEMASK_ALLOC(nodemask_t, unlinked_nodes, GFP_KERNEL); 419 unsigned long pfn, sect_start_pfn, sect_end_pfn; 420 421 if (!mem_blk) { 422 NODEMASK_FREE(unlinked_nodes); 423 return -EFAULT; 424 } 425 if (!unlinked_nodes) 426 return -ENOMEM; 427 nodes_clear(*unlinked_nodes); 428 429 sect_start_pfn = section_nr_to_pfn(phys_index); 430 sect_end_pfn = sect_start_pfn + PAGES_PER_SECTION - 1; 431 for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) { 432 int nid; 433 434 nid = get_nid_for_pfn(pfn); 435 if (nid < 0) 436 continue; 437 if (!node_online(nid)) 438 continue; 439 if (node_test_and_set(nid, *unlinked_nodes)) 440 continue; 441 sysfs_remove_link(&node_devices[nid]->dev.kobj, 442 kobject_name(&mem_blk->dev.kobj)); 443 sysfs_remove_link(&mem_blk->dev.kobj, 444 kobject_name(&node_devices[nid]->dev.kobj)); 445 } 446 NODEMASK_FREE(unlinked_nodes); 447 return 0; 448 } 449 450 static int link_mem_sections(int nid) 451 { 452 unsigned long start_pfn = NODE_DATA(nid)->node_start_pfn; 453 unsigned long end_pfn = start_pfn + NODE_DATA(nid)->node_spanned_pages; 454 unsigned long pfn; 455 struct memory_block *mem_blk = NULL; 456 int err = 0; 457 458 for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) { 459 unsigned long section_nr = pfn_to_section_nr(pfn); 460 struct mem_section *mem_sect; 461 int ret; 462 463 if (!present_section_nr(section_nr)) 464 continue; 465 mem_sect = __nr_to_section(section_nr); 466 467 /* same memblock ? */ 468 if (mem_blk) 469 if ((section_nr >= mem_blk->start_section_nr) && 470 (section_nr <= mem_blk->end_section_nr)) 471 continue; 472 473 mem_blk = find_memory_block_hinted(mem_sect, mem_blk); 474 475 ret = register_mem_sect_under_node(mem_blk, nid); 476 if (!err) 477 err = ret; 478 479 /* discard ref obtained in find_memory_block() */ 480 } 481 482 if (mem_blk) 483 kobject_put(&mem_blk->dev.kobj); 484 return err; 485 } 486 487 #ifdef CONFIG_HUGETLBFS 488 /* 489 * Handle per node hstate attribute [un]registration on transistions 490 * to/from memoryless state. 491 */ 492 static void node_hugetlb_work(struct work_struct *work) 493 { 494 struct node *node = container_of(work, struct node, node_work); 495 496 /* 497 * We only get here when a node transitions to/from memoryless state. 498 * We can detect which transition occurred by examining whether the 499 * node has memory now. hugetlb_register_node() already check this 500 * so we try to register the attributes. If that fails, then the 501 * node has transitioned to memoryless, try to unregister the 502 * attributes. 503 */ 504 if (!hugetlb_register_node(node)) 505 hugetlb_unregister_node(node); 506 } 507 508 static void init_node_hugetlb_work(int nid) 509 { 510 INIT_WORK(&node_devices[nid]->node_work, node_hugetlb_work); 511 } 512 513 static int node_memory_callback(struct notifier_block *self, 514 unsigned long action, void *arg) 515 { 516 struct memory_notify *mnb = arg; 517 int nid = mnb->status_change_nid; 518 519 switch (action) { 520 case MEM_ONLINE: 521 case MEM_OFFLINE: 522 /* 523 * offload per node hstate [un]registration to a work thread 524 * when transitioning to/from memoryless state. 525 */ 526 if (nid != NUMA_NO_NODE) 527 schedule_work(&node_devices[nid]->node_work); 528 break; 529 530 case MEM_GOING_ONLINE: 531 case MEM_GOING_OFFLINE: 532 case MEM_CANCEL_ONLINE: 533 case MEM_CANCEL_OFFLINE: 534 default: 535 break; 536 } 537 538 return NOTIFY_OK; 539 } 540 #endif /* CONFIG_HUGETLBFS */ 541 #else /* !CONFIG_MEMORY_HOTPLUG_SPARSE */ 542 543 static int link_mem_sections(int nid) { return 0; } 544 #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */ 545 546 #if !defined(CONFIG_MEMORY_HOTPLUG_SPARSE) || \ 547 !defined(CONFIG_HUGETLBFS) 548 static inline int node_memory_callback(struct notifier_block *self, 549 unsigned long action, void *arg) 550 { 551 return NOTIFY_OK; 552 } 553 554 static void init_node_hugetlb_work(int nid) { } 555 556 #endif 557 558 int register_one_node(int nid) 559 { 560 int error = 0; 561 int cpu; 562 563 if (node_online(nid)) { 564 int p_node = parent_node(nid); 565 struct node *parent = NULL; 566 567 if (p_node != nid) 568 parent = node_devices[p_node]; 569 570 node_devices[nid] = kzalloc(sizeof(struct node), GFP_KERNEL); 571 if (!node_devices[nid]) 572 return -ENOMEM; 573 574 error = register_node(node_devices[nid], nid, parent); 575 576 /* link cpu under this node */ 577 for_each_present_cpu(cpu) { 578 if (cpu_to_node(cpu) == nid) 579 register_cpu_under_node(cpu, nid); 580 } 581 582 /* link memory sections under this node */ 583 error = link_mem_sections(nid); 584 585 /* initialize work queue for memory hot plug */ 586 init_node_hugetlb_work(nid); 587 } 588 589 return error; 590 591 } 592 593 void unregister_one_node(int nid) 594 { 595 if (!node_devices[nid]) 596 return; 597 598 unregister_node(node_devices[nid]); 599 node_devices[nid] = NULL; 600 } 601 602 /* 603 * node states attributes 604 */ 605 606 static ssize_t print_nodes_state(enum node_states state, char *buf) 607 { 608 int n; 609 610 n = scnprintf(buf, PAGE_SIZE - 1, "%*pbl", 611 nodemask_pr_args(&node_states[state])); 612 buf[n++] = '\n'; 613 buf[n] = '\0'; 614 return n; 615 } 616 617 struct node_attr { 618 struct device_attribute attr; 619 enum node_states state; 620 }; 621 622 static ssize_t show_node_state(struct device *dev, 623 struct device_attribute *attr, char *buf) 624 { 625 struct node_attr *na = container_of(attr, struct node_attr, attr); 626 return print_nodes_state(na->state, buf); 627 } 628 629 #define _NODE_ATTR(name, state) \ 630 { __ATTR(name, 0444, show_node_state, NULL), state } 631 632 static struct node_attr node_state_attr[] = { 633 [N_POSSIBLE] = _NODE_ATTR(possible, N_POSSIBLE), 634 [N_ONLINE] = _NODE_ATTR(online, N_ONLINE), 635 [N_NORMAL_MEMORY] = _NODE_ATTR(has_normal_memory, N_NORMAL_MEMORY), 636 #ifdef CONFIG_HIGHMEM 637 [N_HIGH_MEMORY] = _NODE_ATTR(has_high_memory, N_HIGH_MEMORY), 638 #endif 639 #ifdef CONFIG_MOVABLE_NODE 640 [N_MEMORY] = _NODE_ATTR(has_memory, N_MEMORY), 641 #endif 642 [N_CPU] = _NODE_ATTR(has_cpu, N_CPU), 643 }; 644 645 static struct attribute *node_state_attrs[] = { 646 &node_state_attr[N_POSSIBLE].attr.attr, 647 &node_state_attr[N_ONLINE].attr.attr, 648 &node_state_attr[N_NORMAL_MEMORY].attr.attr, 649 #ifdef CONFIG_HIGHMEM 650 &node_state_attr[N_HIGH_MEMORY].attr.attr, 651 #endif 652 #ifdef CONFIG_MOVABLE_NODE 653 &node_state_attr[N_MEMORY].attr.attr, 654 #endif 655 &node_state_attr[N_CPU].attr.attr, 656 NULL 657 }; 658 659 static struct attribute_group memory_root_attr_group = { 660 .attrs = node_state_attrs, 661 }; 662 663 static const struct attribute_group *cpu_root_attr_groups[] = { 664 &memory_root_attr_group, 665 NULL, 666 }; 667 668 #define NODE_CALLBACK_PRI 2 /* lower than SLAB */ 669 static int __init register_node_type(void) 670 { 671 int ret; 672 673 BUILD_BUG_ON(ARRAY_SIZE(node_state_attr) != NR_NODE_STATES); 674 BUILD_BUG_ON(ARRAY_SIZE(node_state_attrs)-1 != NR_NODE_STATES); 675 676 ret = subsys_system_register(&node_subsys, cpu_root_attr_groups); 677 if (!ret) { 678 static struct notifier_block node_memory_callback_nb = { 679 .notifier_call = node_memory_callback, 680 .priority = NODE_CALLBACK_PRI, 681 }; 682 register_hotmemory_notifier(&node_memory_callback_nb); 683 } 684 685 /* 686 * Note: we're not going to unregister the node class if we fail 687 * to register the node state class attribute files. 688 */ 689 return ret; 690 } 691 postcore_initcall(register_node_type); 692