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v3.15
  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(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
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		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 */
308void 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
323struct node *node_devices[MAX_NUMNODES];
324
325/*
326 * register cpu under node
327 */
328int 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
351int 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
373static 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 */
386int 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 */
422int 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
457static 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 */
499static 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
515static void init_node_hugetlb_work(int nid)
516{
517	INIT_WORK(&node_devices[nid]->node_work, node_hugetlb_work);
518}
519
520static 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
550static 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)
555static inline int node_memory_callback(struct notifier_block *self,
556				unsigned long action, void *arg)
557{
558	return NOTIFY_OK;
559}
560
561static void init_node_hugetlb_work(int nid) { }
562
563#endif
564
565int 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
600void unregister_one_node(int nid)
601{
602	if (!node_devices[nid])
603		return;
604
605	unregister_node(node_devices[nid]);
606	kfree(node_devices[nid]);
607	node_devices[nid] = NULL;
608}
609
610/*
611 * node states attributes
612 */
613
614static ssize_t print_nodes_state(enum node_states state, char *buf)
615{
616	int n;
617
618	n = nodelist_scnprintf(buf, PAGE_SIZE-2, node_states[state]);
619	buf[n++] = '\n';
620	buf[n] = '\0';
 
 
621	return n;
622}
623
624struct node_attr {
625	struct device_attribute attr;
626	enum node_states state;
627};
628
629static ssize_t show_node_state(struct device *dev,
630			       struct device_attribute *attr, char *buf)
631{
632	struct node_attr *na = container_of(attr, struct node_attr, attr);
633	return print_nodes_state(na->state, buf);
634}
635
636#define _NODE_ATTR(name, state) \
637	{ __ATTR(name, 0444, show_node_state, NULL), state }
638
639static struct node_attr node_state_attr[] = {
640	[N_POSSIBLE] = _NODE_ATTR(possible, N_POSSIBLE),
641	[N_ONLINE] = _NODE_ATTR(online, N_ONLINE),
642	[N_NORMAL_MEMORY] = _NODE_ATTR(has_normal_memory, N_NORMAL_MEMORY),
 
643#ifdef CONFIG_HIGHMEM
644	[N_HIGH_MEMORY] = _NODE_ATTR(has_high_memory, N_HIGH_MEMORY),
645#endif
646#ifdef CONFIG_MOVABLE_NODE
647	[N_MEMORY] = _NODE_ATTR(has_memory, N_MEMORY),
648#endif
649	[N_CPU] = _NODE_ATTR(has_cpu, N_CPU),
650};
651
652static struct attribute *node_state_attrs[] = {
653	&node_state_attr[N_POSSIBLE].attr.attr,
654	&node_state_attr[N_ONLINE].attr.attr,
655	&node_state_attr[N_NORMAL_MEMORY].attr.attr,
 
656#ifdef CONFIG_HIGHMEM
657	&node_state_attr[N_HIGH_MEMORY].attr.attr,
658#endif
659#ifdef CONFIG_MOVABLE_NODE
660	&node_state_attr[N_MEMORY].attr.attr,
661#endif
662	&node_state_attr[N_CPU].attr.attr,
663	NULL
664};
665
666static struct attribute_group memory_root_attr_group = {
667	.attrs = node_state_attrs,
668};
669
670static const struct attribute_group *cpu_root_attr_groups[] = {
671	&memory_root_attr_group,
672	NULL,
673};
674
675#define NODE_CALLBACK_PRI	2	/* lower than SLAB */
676static int __init register_node_type(void)
677{
678	int ret;
679
680 	BUILD_BUG_ON(ARRAY_SIZE(node_state_attr) != NR_NODE_STATES);
681 	BUILD_BUG_ON(ARRAY_SIZE(node_state_attrs)-1 != NR_NODE_STATES);
682
683	ret = subsys_system_register(&node_subsys, cpu_root_attr_groups);
684	if (!ret) {
685		static struct notifier_block node_memory_callback_nb = {
686			.notifier_call = node_memory_callback,
687			.priority = NODE_CALLBACK_PRI,
688		};
689		register_hotmemory_notifier(&node_memory_callback_nb);
690	}
691
692	/*
693	 * Note:  we're not going to unregister the node class if we fail
694	 * to register the node state class attribute files.
695	 */
696	return ret;
697}
698postcore_initcall(register_node_type);
v3.1
  1/*
  2 * drivers/base/node.c - basic Node class support
  3 */
  4
  5#include <linux/sysdev.h>
  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/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 sysdev_class_attribute *node_state_attrs[];
 23
 24static struct sysdev_class node_class = {
 25	.name = "node",
 26	.attrs = node_state_attrs,
 27};
 28
 29
 30static ssize_t node_read_cpumap(struct sys_device *dev, int type, char *buf)
 31{
 32	struct node *node_dev = to_node(dev);
 33	const struct cpumask *mask = cpumask_of_node(node_dev->sysdev.id);
 34	int len;
 35
 36	/* 2008/04/07: buf currently PAGE_SIZE, need 9 chars per 32 bits. */
 37	BUILD_BUG_ON((NR_CPUS/32 * 9) > (PAGE_SIZE-1));
 38
 39	len = type?
 40		cpulist_scnprintf(buf, PAGE_SIZE-2, mask) :
 41		cpumask_scnprintf(buf, PAGE_SIZE-2, mask);
 42 	buf[len++] = '\n';
 43 	buf[len] = '\0';
 44	return len;
 45}
 46
 47static inline ssize_t node_read_cpumask(struct sys_device *dev,
 48				struct sysdev_attribute *attr, char *buf)
 49{
 50	return node_read_cpumap(dev, 0, buf);
 51}
 52static inline ssize_t node_read_cpulist(struct sys_device *dev,
 53				struct sysdev_attribute *attr, char *buf)
 54{
 55	return node_read_cpumap(dev, 1, buf);
 56}
 57
 58static SYSDEV_ATTR(cpumap,  S_IRUGO, node_read_cpumask, NULL);
 59static SYSDEV_ATTR(cpulist, S_IRUGO, node_read_cpulist, NULL);
 60
 61#define K(x) ((x) << (PAGE_SHIFT - 10))
 62static ssize_t node_read_meminfo(struct sys_device * dev,
 63			struct sysdev_attribute *attr, char * buf)
 64{
 65	int n;
 66	int nid = dev->id;
 67	struct sysinfo i;
 68
 69	si_meminfo_node(&i, nid);
 70	n = sprintf(buf,
 71		       "Node %d MemTotal:       %8lu kB\n"
 72		       "Node %d MemFree:        %8lu kB\n"
 73		       "Node %d MemUsed:        %8lu kB\n"
 74		       "Node %d Active:         %8lu kB\n"
 75		       "Node %d Inactive:       %8lu kB\n"
 76		       "Node %d Active(anon):   %8lu kB\n"
 77		       "Node %d Inactive(anon): %8lu kB\n"
 78		       "Node %d Active(file):   %8lu kB\n"
 79		       "Node %d Inactive(file): %8lu kB\n"
 80		       "Node %d Unevictable:    %8lu kB\n"
 81		       "Node %d Mlocked:        %8lu kB\n",
 82		       nid, K(i.totalram),
 83		       nid, K(i.freeram),
 84		       nid, K(i.totalram - i.freeram),
 85		       nid, K(node_page_state(nid, NR_ACTIVE_ANON) +
 86				node_page_state(nid, NR_ACTIVE_FILE)),
 87		       nid, K(node_page_state(nid, NR_INACTIVE_ANON) +
 88				node_page_state(nid, NR_INACTIVE_FILE)),
 89		       nid, K(node_page_state(nid, NR_ACTIVE_ANON)),
 90		       nid, K(node_page_state(nid, NR_INACTIVE_ANON)),
 91		       nid, K(node_page_state(nid, NR_ACTIVE_FILE)),
 92		       nid, K(node_page_state(nid, NR_INACTIVE_FILE)),
 93		       nid, K(node_page_state(nid, NR_UNEVICTABLE)),
 94		       nid, K(node_page_state(nid, NR_MLOCK)));
 95
 96#ifdef CONFIG_HIGHMEM
 97	n += sprintf(buf + n,
 98		       "Node %d HighTotal:      %8lu kB\n"
 99		       "Node %d HighFree:       %8lu kB\n"
100		       "Node %d LowTotal:       %8lu kB\n"
101		       "Node %d LowFree:        %8lu kB\n",
102		       nid, K(i.totalhigh),
103		       nid, K(i.freehigh),
104		       nid, K(i.totalram - i.totalhigh),
105		       nid, K(i.freeram - i.freehigh));
106#endif
107	n += sprintf(buf + n,
108		       "Node %d Dirty:          %8lu kB\n"
109		       "Node %d Writeback:      %8lu kB\n"
110		       "Node %d FilePages:      %8lu kB\n"
111		       "Node %d Mapped:         %8lu kB\n"
112		       "Node %d AnonPages:      %8lu kB\n"
113		       "Node %d Shmem:          %8lu kB\n"
114		       "Node %d KernelStack:    %8lu kB\n"
115		       "Node %d PageTables:     %8lu kB\n"
116		       "Node %d NFS_Unstable:   %8lu kB\n"
117		       "Node %d Bounce:         %8lu kB\n"
118		       "Node %d WritebackTmp:   %8lu kB\n"
119		       "Node %d Slab:           %8lu kB\n"
120		       "Node %d SReclaimable:   %8lu kB\n"
121		       "Node %d SUnreclaim:     %8lu kB\n"
122#ifdef CONFIG_TRANSPARENT_HUGEPAGE
123		       "Node %d AnonHugePages:  %8lu kB\n"
124#endif
125			,
126		       nid, K(node_page_state(nid, NR_FILE_DIRTY)),
127		       nid, K(node_page_state(nid, NR_WRITEBACK)),
128		       nid, K(node_page_state(nid, NR_FILE_PAGES)),
129		       nid, K(node_page_state(nid, NR_FILE_MAPPED)),
130		       nid, K(node_page_state(nid, NR_ANON_PAGES)
131#ifdef CONFIG_TRANSPARENT_HUGEPAGE
132			+ node_page_state(nid, NR_ANON_TRANSPARENT_HUGEPAGES) *
133			HPAGE_PMD_NR
134#endif
135		       ),
136		       nid, K(node_page_state(nid, NR_SHMEM)),
137		       nid, node_page_state(nid, NR_KERNEL_STACK) *
138				THREAD_SIZE / 1024,
139		       nid, K(node_page_state(nid, NR_PAGETABLE)),
140		       nid, K(node_page_state(nid, NR_UNSTABLE_NFS)),
141		       nid, K(node_page_state(nid, NR_BOUNCE)),
142		       nid, K(node_page_state(nid, NR_WRITEBACK_TEMP)),
143		       nid, K(node_page_state(nid, NR_SLAB_RECLAIMABLE) +
144				node_page_state(nid, NR_SLAB_UNRECLAIMABLE)),
145		       nid, K(node_page_state(nid, NR_SLAB_RECLAIMABLE)),
 
146		       nid, K(node_page_state(nid, NR_SLAB_UNRECLAIMABLE))
147#ifdef CONFIG_TRANSPARENT_HUGEPAGE
148			, nid,
149			K(node_page_state(nid, NR_ANON_TRANSPARENT_HUGEPAGES) *
150			HPAGE_PMD_NR)
 
 
151#endif
152		       );
153	n += hugetlb_report_node_meminfo(nid, buf + n);
154	return n;
155}
156
157#undef K
158static SYSDEV_ATTR(meminfo, S_IRUGO, node_read_meminfo, NULL);
159
160static ssize_t node_read_numastat(struct sys_device * dev,
161				struct sysdev_attribute *attr, char * buf)
162{
163	return sprintf(buf,
164		       "numa_hit %lu\n"
165		       "numa_miss %lu\n"
166		       "numa_foreign %lu\n"
167		       "interleave_hit %lu\n"
168		       "local_node %lu\n"
169		       "other_node %lu\n",
170		       node_page_state(dev->id, NUMA_HIT),
171		       node_page_state(dev->id, NUMA_MISS),
172		       node_page_state(dev->id, NUMA_FOREIGN),
173		       node_page_state(dev->id, NUMA_INTERLEAVE_HIT),
174		       node_page_state(dev->id, NUMA_LOCAL),
175		       node_page_state(dev->id, NUMA_OTHER));
176}
177static SYSDEV_ATTR(numastat, S_IRUGO, node_read_numastat, NULL);
178
179static ssize_t node_read_vmstat(struct sys_device *dev,
180				struct sysdev_attribute *attr, char *buf)
181{
182	int nid = dev->id;
183	int i;
184	int n = 0;
185
186	for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
187		n += sprintf(buf+n, "%s %lu\n", vmstat_text[i],
188			     node_page_state(nid, i));
189
190	return n;
191}
192static SYSDEV_ATTR(vmstat, S_IRUGO, node_read_vmstat, NULL);
193
194static ssize_t node_read_distance(struct sys_device * dev,
195			struct sysdev_attribute *attr, char * buf)
196{
197	int nid = dev->id;
198	int len = 0;
199	int i;
200
201	/*
202	 * buf is currently PAGE_SIZE in length and each node needs 4 chars
203	 * at the most (distance + space or newline).
204	 */
205	BUILD_BUG_ON(MAX_NUMNODES * 4 > PAGE_SIZE);
206
207	for_each_online_node(i)
208		len += sprintf(buf + len, "%s%d", i ? " " : "", node_distance(nid, i));
209
210	len += sprintf(buf + len, "\n");
211	return len;
212}
213static SYSDEV_ATTR(distance, S_IRUGO, node_read_distance, NULL);
214
215#ifdef CONFIG_HUGETLBFS
216/*
217 * hugetlbfs per node attributes registration interface:
218 * When/if hugetlb[fs] subsystem initializes [sometime after this module],
219 * it will register its per node attributes for all online nodes with
220 * memory.  It will also call register_hugetlbfs_with_node(), below, to
221 * register its attribute registration functions with this node driver.
222 * Once these hooks have been initialized, the node driver will call into
223 * the hugetlb module to [un]register attributes for hot-plugged nodes.
224 */
225static node_registration_func_t __hugetlb_register_node;
226static node_registration_func_t __hugetlb_unregister_node;
227
228static inline bool hugetlb_register_node(struct node *node)
229{
230	if (__hugetlb_register_node &&
231			node_state(node->sysdev.id, N_HIGH_MEMORY)) {
232		__hugetlb_register_node(node);
233		return true;
234	}
235	return false;
236}
237
238static inline void hugetlb_unregister_node(struct node *node)
239{
240	if (__hugetlb_unregister_node)
241		__hugetlb_unregister_node(node);
242}
243
244void register_hugetlbfs_with_node(node_registration_func_t doregister,
245				  node_registration_func_t unregister)
246{
247	__hugetlb_register_node   = doregister;
248	__hugetlb_unregister_node = unregister;
249}
250#else
251static inline void hugetlb_register_node(struct node *node) {}
252
253static inline void hugetlb_unregister_node(struct node *node) {}
254#endif
255
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
256
257/*
258 * register_node - Setup a sysfs device for a node.
259 * @num - Node number to use when creating the device.
260 *
261 * Initialize and register the node device.
262 */
263int register_node(struct node *node, int num, struct node *parent)
264{
265	int error;
266
267	node->sysdev.id = num;
268	node->sysdev.cls = &node_class;
269	error = sysdev_register(&node->sysdev);
 
270
271	if (!error){
272		sysdev_create_file(&node->sysdev, &attr_cpumap);
273		sysdev_create_file(&node->sysdev, &attr_cpulist);
274		sysdev_create_file(&node->sysdev, &attr_meminfo);
275		sysdev_create_file(&node->sysdev, &attr_numastat);
276		sysdev_create_file(&node->sysdev, &attr_distance);
277		sysdev_create_file(&node->sysdev, &attr_vmstat);
278
279		scan_unevictable_register_node(node);
280
281		hugetlb_register_node(node);
282
283		compaction_register_node(node);
284	}
285	return error;
286}
287
288/**
289 * unregister_node - unregister a node device
290 * @node: node going away
291 *
292 * Unregisters a node device @node.  All the devices on the node must be
293 * unregistered before calling this function.
294 */
295void unregister_node(struct node *node)
296{
297	sysdev_remove_file(&node->sysdev, &attr_cpumap);
298	sysdev_remove_file(&node->sysdev, &attr_cpulist);
299	sysdev_remove_file(&node->sysdev, &attr_meminfo);
300	sysdev_remove_file(&node->sysdev, &attr_numastat);
301	sysdev_remove_file(&node->sysdev, &attr_distance);
302	sysdev_remove_file(&node->sysdev, &attr_vmstat);
303
304	scan_unevictable_unregister_node(node);
305	hugetlb_unregister_node(node);		/* no-op, if memoryless node */
306
307	sysdev_unregister(&node->sysdev);
308}
309
310struct node node_devices[MAX_NUMNODES];
311
312/*
313 * register cpu under node
314 */
315int register_cpu_under_node(unsigned int cpu, unsigned int nid)
316{
317	int ret;
318	struct sys_device *obj;
319
320	if (!node_online(nid))
321		return 0;
322
323	obj = get_cpu_sysdev(cpu);
324	if (!obj)
325		return 0;
326
327	ret = sysfs_create_link(&node_devices[nid].sysdev.kobj,
328				&obj->kobj,
329				kobject_name(&obj->kobj));
330	if (ret)
331		return ret;
332
333	return sysfs_create_link(&obj->kobj,
334				 &node_devices[nid].sysdev.kobj,
335				 kobject_name(&node_devices[nid].sysdev.kobj));
336}
337
338int unregister_cpu_under_node(unsigned int cpu, unsigned int nid)
339{
340	struct sys_device *obj;
341
342	if (!node_online(nid))
343		return 0;
344
345	obj = get_cpu_sysdev(cpu);
346	if (!obj)
347		return 0;
348
349	sysfs_remove_link(&node_devices[nid].sysdev.kobj,
350			  kobject_name(&obj->kobj));
351	sysfs_remove_link(&obj->kobj,
352			  kobject_name(&node_devices[nid].sysdev.kobj));
353
354	return 0;
355}
356
357#ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
358#define page_initialized(page)  (page->lru.next)
359
360static int get_nid_for_pfn(unsigned long pfn)
361{
362	struct page *page;
363
364	if (!pfn_valid_within(pfn))
365		return -1;
366	page = pfn_to_page(pfn);
367	if (!page_initialized(page))
368		return -1;
369	return pfn_to_nid(pfn);
370}
371
372/* register memory section under specified node if it spans that node */
373int register_mem_sect_under_node(struct memory_block *mem_blk, int nid)
374{
375	int ret;
376	unsigned long pfn, sect_start_pfn, sect_end_pfn;
377
378	if (!mem_blk)
379		return -EFAULT;
380	if (!node_online(nid))
381		return 0;
382
383	sect_start_pfn = section_nr_to_pfn(mem_blk->start_section_nr);
384	sect_end_pfn = section_nr_to_pfn(mem_blk->end_section_nr);
385	sect_end_pfn += PAGES_PER_SECTION - 1;
386	for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
387		int page_nid;
388
389		page_nid = get_nid_for_pfn(pfn);
390		if (page_nid < 0)
391			continue;
392		if (page_nid != nid)
393			continue;
394		ret = sysfs_create_link_nowarn(&node_devices[nid].sysdev.kobj,
395					&mem_blk->sysdev.kobj,
396					kobject_name(&mem_blk->sysdev.kobj));
397		if (ret)
398			return ret;
399
400		return sysfs_create_link_nowarn(&mem_blk->sysdev.kobj,
401				&node_devices[nid].sysdev.kobj,
402				kobject_name(&node_devices[nid].sysdev.kobj));
403	}
404	/* mem section does not span the specified node */
405	return 0;
406}
407
408/* unregister memory section under all nodes that it spans */
409int unregister_mem_sect_under_nodes(struct memory_block *mem_blk,
410				    unsigned long phys_index)
411{
412	NODEMASK_ALLOC(nodemask_t, unlinked_nodes, GFP_KERNEL);
413	unsigned long pfn, sect_start_pfn, sect_end_pfn;
414
415	if (!mem_blk) {
416		NODEMASK_FREE(unlinked_nodes);
417		return -EFAULT;
418	}
419	if (!unlinked_nodes)
420		return -ENOMEM;
421	nodes_clear(*unlinked_nodes);
422
423	sect_start_pfn = section_nr_to_pfn(phys_index);
424	sect_end_pfn = sect_start_pfn + PAGES_PER_SECTION - 1;
425	for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
426		int nid;
427
428		nid = get_nid_for_pfn(pfn);
429		if (nid < 0)
430			continue;
431		if (!node_online(nid))
432			continue;
433		if (node_test_and_set(nid, *unlinked_nodes))
434			continue;
435		sysfs_remove_link(&node_devices[nid].sysdev.kobj,
436			 kobject_name(&mem_blk->sysdev.kobj));
437		sysfs_remove_link(&mem_blk->sysdev.kobj,
438			 kobject_name(&node_devices[nid].sysdev.kobj));
439	}
440	NODEMASK_FREE(unlinked_nodes);
441	return 0;
442}
443
444static int link_mem_sections(int nid)
445{
446	unsigned long start_pfn = NODE_DATA(nid)->node_start_pfn;
447	unsigned long end_pfn = start_pfn + NODE_DATA(nid)->node_spanned_pages;
448	unsigned long pfn;
449	struct memory_block *mem_blk = NULL;
450	int err = 0;
451
452	for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
453		unsigned long section_nr = pfn_to_section_nr(pfn);
454		struct mem_section *mem_sect;
455		int ret;
456
457		if (!present_section_nr(section_nr))
458			continue;
459		mem_sect = __nr_to_section(section_nr);
 
 
 
 
 
 
 
460		mem_blk = find_memory_block_hinted(mem_sect, mem_blk);
 
461		ret = register_mem_sect_under_node(mem_blk, nid);
462		if (!err)
463			err = ret;
464
465		/* discard ref obtained in find_memory_block() */
466	}
467
468	if (mem_blk)
469		kobject_put(&mem_blk->sysdev.kobj);
470	return err;
471}
472
473#ifdef CONFIG_HUGETLBFS
474/*
475 * Handle per node hstate attribute [un]registration on transistions
476 * to/from memoryless state.
477 */
478static void node_hugetlb_work(struct work_struct *work)
479{
480	struct node *node = container_of(work, struct node, node_work);
481
482	/*
483	 * We only get here when a node transitions to/from memoryless state.
484	 * We can detect which transition occurred by examining whether the
485	 * node has memory now.  hugetlb_register_node() already check this
486	 * so we try to register the attributes.  If that fails, then the
487	 * node has transitioned to memoryless, try to unregister the
488	 * attributes.
489	 */
490	if (!hugetlb_register_node(node))
491		hugetlb_unregister_node(node);
492}
493
494static void init_node_hugetlb_work(int nid)
495{
496	INIT_WORK(&node_devices[nid].node_work, node_hugetlb_work);
497}
498
499static int node_memory_callback(struct notifier_block *self,
500				unsigned long action, void *arg)
501{
502	struct memory_notify *mnb = arg;
503	int nid = mnb->status_change_nid;
504
505	switch (action) {
506	case MEM_ONLINE:
507	case MEM_OFFLINE:
508		/*
509		 * offload per node hstate [un]registration to a work thread
510		 * when transitioning to/from memoryless state.
511		 */
512		if (nid != NUMA_NO_NODE)
513			schedule_work(&node_devices[nid].node_work);
514		break;
515
516	case MEM_GOING_ONLINE:
517	case MEM_GOING_OFFLINE:
518	case MEM_CANCEL_ONLINE:
519	case MEM_CANCEL_OFFLINE:
520	default:
521		break;
522	}
523
524	return NOTIFY_OK;
525}
526#endif	/* CONFIG_HUGETLBFS */
527#else	/* !CONFIG_MEMORY_HOTPLUG_SPARSE */
528
529static int link_mem_sections(int nid) { return 0; }
530#endif	/* CONFIG_MEMORY_HOTPLUG_SPARSE */
531
532#if !defined(CONFIG_MEMORY_HOTPLUG_SPARSE) || \
533    !defined(CONFIG_HUGETLBFS)
534static inline int node_memory_callback(struct notifier_block *self,
535				unsigned long action, void *arg)
536{
537	return NOTIFY_OK;
538}
539
540static void init_node_hugetlb_work(int nid) { }
541
542#endif
543
544int register_one_node(int nid)
545{
546	int error = 0;
547	int cpu;
548
549	if (node_online(nid)) {
550		int p_node = parent_node(nid);
551		struct node *parent = NULL;
552
553		if (p_node != nid)
554			parent = &node_devices[p_node];
 
 
 
 
555
556		error = register_node(&node_devices[nid], nid, parent);
557
558		/* link cpu under this node */
559		for_each_present_cpu(cpu) {
560			if (cpu_to_node(cpu) == nid)
561				register_cpu_under_node(cpu, nid);
562		}
563
564		/* link memory sections under this node */
565		error = link_mem_sections(nid);
566
567		/* initialize work queue for memory hot plug */
568		init_node_hugetlb_work(nid);
569	}
570
571	return error;
572
573}
574
575void unregister_one_node(int nid)
576{
577	unregister_node(&node_devices[nid]);
 
 
 
 
 
578}
579
580/*
581 * node states attributes
582 */
583
584static ssize_t print_nodes_state(enum node_states state, char *buf)
585{
586	int n;
587
588	n = nodelist_scnprintf(buf, PAGE_SIZE, node_states[state]);
589	if (n > 0 && PAGE_SIZE > n + 1) {
590		*(buf + n++) = '\n';
591		*(buf + n++) = '\0';
592	}
593	return n;
594}
595
596struct node_attr {
597	struct sysdev_class_attribute attr;
598	enum node_states state;
599};
600
601static ssize_t show_node_state(struct sysdev_class *class,
602			       struct sysdev_class_attribute *attr, char *buf)
603{
604	struct node_attr *na = container_of(attr, struct node_attr, attr);
605	return print_nodes_state(na->state, buf);
606}
607
608#define _NODE_ATTR(name, state) \
609	{ _SYSDEV_CLASS_ATTR(name, 0444, show_node_state, NULL), state }
610
611static struct node_attr node_state_attr[] = {
612	_NODE_ATTR(possible, N_POSSIBLE),
613	_NODE_ATTR(online, N_ONLINE),
614	_NODE_ATTR(has_normal_memory, N_NORMAL_MEMORY),
615	_NODE_ATTR(has_cpu, N_CPU),
616#ifdef CONFIG_HIGHMEM
617	_NODE_ATTR(has_high_memory, N_HIGH_MEMORY),
 
 
 
618#endif
 
619};
620
621static struct sysdev_class_attribute *node_state_attrs[] = {
622	&node_state_attr[0].attr,
623	&node_state_attr[1].attr,
624	&node_state_attr[2].attr,
625	&node_state_attr[3].attr,
626#ifdef CONFIG_HIGHMEM
627	&node_state_attr[4].attr,
628#endif
 
 
 
 
629	NULL
630};
631
 
 
 
 
 
 
 
 
 
632#define NODE_CALLBACK_PRI	2	/* lower than SLAB */
633static int __init register_node_type(void)
634{
635	int ret;
636
637 	BUILD_BUG_ON(ARRAY_SIZE(node_state_attr) != NR_NODE_STATES);
638 	BUILD_BUG_ON(ARRAY_SIZE(node_state_attrs)-1 != NR_NODE_STATES);
639
640	ret = sysdev_class_register(&node_class);
641	if (!ret) {
642		hotplug_memory_notifier(node_memory_callback,
643					NODE_CALLBACK_PRI);
 
 
 
644	}
645
646	/*
647	 * Note:  we're not going to unregister the node class if we fail
648	 * to register the node state class attribute files.
649	 */
650	return ret;
651}
652postcore_initcall(register_node_type);