Merge branch 'for-linus' into for-linus-3.12
[platform/adaptation/renesas_rcar/renesas_kernel.git] / 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, 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
45 static 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 }
50 static 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
56 static DEVICE_ATTR(cpumap,  S_IRUGO, node_read_cpumask, NULL);
57 static DEVICE_ATTR(cpulist, S_IRUGO, node_read_cpulist, NULL);
58
59 #define K(x) ((x) << (PAGE_SHIFT - 10))
60 static 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(node_page_state(nid, NR_SHMEM)),
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
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                        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 }
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         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 }
186 static DEVICE_ATTR(vmstat, S_IRUGO, node_read_vmstat, NULL);
187
188 static 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 }
207 static 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  */
219 static node_registration_func_t __hugetlb_register_node;
220 static node_registration_func_t __hugetlb_unregister_node;
221
222 static 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
232 static inline void hugetlb_unregister_node(struct node *node)
233 {
234         if (__hugetlb_unregister_node)
235                 __hugetlb_unregister_node(node);
236 }
237
238 void 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
245 static inline void hugetlb_register_node(struct node *node) {}
246
247 static inline void hugetlb_unregister_node(struct node *node) {}
248 #endif
249
250 static 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  */
275 static 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                 scan_unevictable_register_node(node);
293
294                 hugetlb_register_node(node);
295
296                 compaction_register_node(node);
297         }
298         return error;
299 }
300
301 /**
302  * unregister_node - unregister a node device
303  * @node: node going away
304  *
305  * Unregisters a node device @node.  All the devices on the node must be
306  * unregistered before calling this function.
307  */
308 void unregister_node(struct node *node)
309 {
310         device_remove_file(&node->dev, &dev_attr_cpumap);
311         device_remove_file(&node->dev, &dev_attr_cpulist);
312         device_remove_file(&node->dev, &dev_attr_meminfo);
313         device_remove_file(&node->dev, &dev_attr_numastat);
314         device_remove_file(&node->dev, &dev_attr_distance);
315         device_remove_file(&node->dev, &dev_attr_vmstat);
316
317         scan_unevictable_unregister_node(node);
318         hugetlb_unregister_node(node);          /* no-op, if memoryless node */
319
320         device_unregister(&node->dev);
321 }
322
323 struct node *node_devices[MAX_NUMNODES];
324
325 /*
326  * register cpu under node
327  */
328 int register_cpu_under_node(unsigned int cpu, unsigned int nid)
329 {
330         int ret;
331         struct device *obj;
332
333         if (!node_online(nid))
334                 return 0;
335
336         obj = get_cpu_device(cpu);
337         if (!obj)
338                 return 0;
339
340         ret = sysfs_create_link(&node_devices[nid]->dev.kobj,
341                                 &obj->kobj,
342                                 kobject_name(&obj->kobj));
343         if (ret)
344                 return ret;
345
346         return sysfs_create_link(&obj->kobj,
347                                  &node_devices[nid]->dev.kobj,
348                                  kobject_name(&node_devices[nid]->dev.kobj));
349 }
350
351 int unregister_cpu_under_node(unsigned int cpu, unsigned int nid)
352 {
353         struct device *obj;
354
355         if (!node_online(nid))
356                 return 0;
357
358         obj = get_cpu_device(cpu);
359         if (!obj)
360                 return 0;
361
362         sysfs_remove_link(&node_devices[nid]->dev.kobj,
363                           kobject_name(&obj->kobj));
364         sysfs_remove_link(&obj->kobj,
365                           kobject_name(&node_devices[nid]->dev.kobj));
366
367         return 0;
368 }
369
370 #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
371 #define page_initialized(page)  (page->lru.next)
372
373 static int get_nid_for_pfn(unsigned long pfn)
374 {
375         struct page *page;
376
377         if (!pfn_valid_within(pfn))
378                 return -1;
379         page = pfn_to_page(pfn);
380         if (!page_initialized(page))
381                 return -1;
382         return pfn_to_nid(pfn);
383 }
384
385 /* register memory section under specified node if it spans that node */
386 int register_mem_sect_under_node(struct memory_block *mem_blk, int nid)
387 {
388         int ret;
389         unsigned long pfn, sect_start_pfn, sect_end_pfn;
390
391         if (!mem_blk)
392                 return -EFAULT;
393         if (!node_online(nid))
394                 return 0;
395
396         sect_start_pfn = section_nr_to_pfn(mem_blk->start_section_nr);
397         sect_end_pfn = section_nr_to_pfn(mem_blk->end_section_nr);
398         sect_end_pfn += PAGES_PER_SECTION - 1;
399         for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
400                 int page_nid;
401
402                 page_nid = get_nid_for_pfn(pfn);
403                 if (page_nid < 0)
404                         continue;
405                 if (page_nid != nid)
406                         continue;
407                 ret = sysfs_create_link_nowarn(&node_devices[nid]->dev.kobj,
408                                         &mem_blk->dev.kobj,
409                                         kobject_name(&mem_blk->dev.kobj));
410                 if (ret)
411                         return ret;
412
413                 return sysfs_create_link_nowarn(&mem_blk->dev.kobj,
414                                 &node_devices[nid]->dev.kobj,
415                                 kobject_name(&node_devices[nid]->dev.kobj));
416         }
417         /* mem section does not span the specified node */
418         return 0;
419 }
420
421 /* unregister memory section under all nodes that it spans */
422 int unregister_mem_sect_under_nodes(struct memory_block *mem_blk,
423                                     unsigned long phys_index)
424 {
425         NODEMASK_ALLOC(nodemask_t, unlinked_nodes, GFP_KERNEL);
426         unsigned long pfn, sect_start_pfn, sect_end_pfn;
427
428         if (!mem_blk) {
429                 NODEMASK_FREE(unlinked_nodes);
430                 return -EFAULT;
431         }
432         if (!unlinked_nodes)
433                 return -ENOMEM;
434         nodes_clear(*unlinked_nodes);
435
436         sect_start_pfn = section_nr_to_pfn(phys_index);
437         sect_end_pfn = sect_start_pfn + PAGES_PER_SECTION - 1;
438         for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
439                 int nid;
440
441                 nid = get_nid_for_pfn(pfn);
442                 if (nid < 0)
443                         continue;
444                 if (!node_online(nid))
445                         continue;
446                 if (node_test_and_set(nid, *unlinked_nodes))
447                         continue;
448                 sysfs_remove_link(&node_devices[nid]->dev.kobj,
449                          kobject_name(&mem_blk->dev.kobj));
450                 sysfs_remove_link(&mem_blk->dev.kobj,
451                          kobject_name(&node_devices[nid]->dev.kobj));
452         }
453         NODEMASK_FREE(unlinked_nodes);
454         return 0;
455 }
456
457 static int link_mem_sections(int nid)
458 {
459         unsigned long start_pfn = NODE_DATA(nid)->node_start_pfn;
460         unsigned long end_pfn = start_pfn + NODE_DATA(nid)->node_spanned_pages;
461         unsigned long pfn;
462         struct memory_block *mem_blk = NULL;
463         int err = 0;
464
465         for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
466                 unsigned long section_nr = pfn_to_section_nr(pfn);
467                 struct mem_section *mem_sect;
468                 int ret;
469
470                 if (!present_section_nr(section_nr))
471                         continue;
472                 mem_sect = __nr_to_section(section_nr);
473
474                 /* same memblock ? */
475                 if (mem_blk)
476                         if ((section_nr >= mem_blk->start_section_nr) &&
477                             (section_nr <= mem_blk->end_section_nr))
478                                 continue;
479
480                 mem_blk = find_memory_block_hinted(mem_sect, mem_blk);
481
482                 ret = register_mem_sect_under_node(mem_blk, nid);
483                 if (!err)
484                         err = ret;
485
486                 /* discard ref obtained in find_memory_block() */
487         }
488
489         if (mem_blk)
490                 kobject_put(&mem_blk->dev.kobj);
491         return err;
492 }
493
494 #ifdef CONFIG_HUGETLBFS
495 /*
496  * Handle per node hstate attribute [un]registration on transistions
497  * to/from memoryless state.
498  */
499 static void node_hugetlb_work(struct work_struct *work)
500 {
501         struct node *node = container_of(work, struct node, node_work);
502
503         /*
504          * We only get here when a node transitions to/from memoryless state.
505          * We can detect which transition occurred by examining whether the
506          * node has memory now.  hugetlb_register_node() already check this
507          * so we try to register the attributes.  If that fails, then the
508          * node has transitioned to memoryless, try to unregister the
509          * attributes.
510          */
511         if (!hugetlb_register_node(node))
512                 hugetlb_unregister_node(node);
513 }
514
515 static void init_node_hugetlb_work(int nid)
516 {
517         INIT_WORK(&node_devices[nid]->node_work, node_hugetlb_work);
518 }
519
520 static int node_memory_callback(struct notifier_block *self,
521                                 unsigned long action, void *arg)
522 {
523         struct memory_notify *mnb = arg;
524         int nid = mnb->status_change_nid;
525
526         switch (action) {
527         case MEM_ONLINE:
528         case MEM_OFFLINE:
529                 /*
530                  * offload per node hstate [un]registration to a work thread
531                  * when transitioning to/from memoryless state.
532                  */
533                 if (nid != NUMA_NO_NODE)
534                         schedule_work(&node_devices[nid]->node_work);
535                 break;
536
537         case MEM_GOING_ONLINE:
538         case MEM_GOING_OFFLINE:
539         case MEM_CANCEL_ONLINE:
540         case MEM_CANCEL_OFFLINE:
541         default:
542                 break;
543         }
544
545         return NOTIFY_OK;
546 }
547 #endif  /* CONFIG_HUGETLBFS */
548 #else   /* !CONFIG_MEMORY_HOTPLUG_SPARSE */
549
550 static int link_mem_sections(int nid) { return 0; }
551 #endif  /* CONFIG_MEMORY_HOTPLUG_SPARSE */
552
553 #if !defined(CONFIG_MEMORY_HOTPLUG_SPARSE) || \
554     !defined(CONFIG_HUGETLBFS)
555 static inline int node_memory_callback(struct notifier_block *self,
556                                 unsigned long action, void *arg)
557 {
558         return NOTIFY_OK;
559 }
560
561 static void init_node_hugetlb_work(int nid) { }
562
563 #endif
564
565 int register_one_node(int nid)
566 {
567         int error = 0;
568         int cpu;
569
570         if (node_online(nid)) {
571                 int p_node = parent_node(nid);
572                 struct node *parent = NULL;
573
574                 if (p_node != nid)
575                         parent = node_devices[p_node];
576
577                 node_devices[nid] = kzalloc(sizeof(struct node), GFP_KERNEL);
578                 if (!node_devices[nid])
579                         return -ENOMEM;
580
581                 error = register_node(node_devices[nid], nid, parent);
582
583                 /* link cpu under this node */
584                 for_each_present_cpu(cpu) {
585                         if (cpu_to_node(cpu) == nid)
586                                 register_cpu_under_node(cpu, nid);
587                 }
588
589                 /* link memory sections under this node */
590                 error = link_mem_sections(nid);
591
592                 /* initialize work queue for memory hot plug */
593                 init_node_hugetlb_work(nid);
594         }
595
596         return error;
597
598 }
599
600 void unregister_one_node(int nid)
601 {
602         unregister_node(node_devices[nid]);
603         node_devices[nid] = NULL;
604 }
605
606 /*
607  * node states attributes
608  */
609
610 static 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
620 struct node_attr {
621         struct device_attribute attr;
622         enum node_states state;
623 };
624
625 static 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
635 static 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
648 static 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
662 static struct attribute_group memory_root_attr_group = {
663         .attrs = node_state_attrs,
664 };
665
666 static 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 */
672 static 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 }
694 postcore_initcall(register_node_type);