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 
node_read_cpumap(struct device * dev,bool list,char * buf)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 
node_read_cpumask(struct device * dev,struct device_attribute * attr,char * buf)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 }
node_read_cpulist(struct device * dev,struct device_attribute * attr,char * buf)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))
node_read_meminfo(struct device * dev,struct device_attribute * attr,char * buf)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 
node_read_numastat(struct device * dev,struct device_attribute * attr,char * buf)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 
node_read_vmstat(struct device * dev,struct device_attribute * attr,char * buf)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 
node_read_distance(struct device * dev,struct device_attribute * attr,char * buf)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 
hugetlb_register_node(struct node * node)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 
hugetlb_unregister_node(struct node * node)237 static inline void hugetlb_unregister_node(struct node *node)
238 {
239 	if (__hugetlb_unregister_node)
240 		__hugetlb_unregister_node(node);
241 }
242 
register_hugetlbfs_with_node(node_registration_func_t doregister,node_registration_func_t unregister)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
hugetlb_register_node(struct node * node)250 static inline void hugetlb_register_node(struct node *node) {}
251 
hugetlb_unregister_node(struct node * node)252 static inline void hugetlb_unregister_node(struct node *node) {}
253 #endif
254 
node_device_release(struct device * dev)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  */
register_node(struct node * node,int num,struct node * parent)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  */
unregister_node(struct node * node)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  */
register_cpu_under_node(unsigned int cpu,unsigned int nid)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 
unregister_cpu_under_node(unsigned int cpu,unsigned int nid)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 
get_nid_for_pfn(unsigned long pfn)362 static int get_nid_for_pfn(unsigned long pfn)
363 {
364 	struct page *page;
365 
366 	if (!pfn_valid_within(pfn))
367 		return -1;
368 	page = pfn_to_page(pfn);
369 	if (!page_initialized(page))
370 		return -1;
371 	return pfn_to_nid(pfn);
372 }
373 
374 /* register memory section under specified node if it spans that node */
register_mem_sect_under_node(struct memory_block * mem_blk,int nid)375 int register_mem_sect_under_node(struct memory_block *mem_blk, int nid)
376 {
377 	int ret;
378 	unsigned long pfn, sect_start_pfn, sect_end_pfn;
379 
380 	if (!mem_blk)
381 		return -EFAULT;
382 	if (!node_online(nid))
383 		return 0;
384 
385 	sect_start_pfn = section_nr_to_pfn(mem_blk->start_section_nr);
386 	sect_end_pfn = section_nr_to_pfn(mem_blk->end_section_nr);
387 	sect_end_pfn += PAGES_PER_SECTION - 1;
388 	for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
389 		int page_nid;
390 
391 		/*
392 		 * memory block could have several absent sections from start.
393 		 * skip pfn range from absent section
394 		 */
395 		if (!pfn_present(pfn)) {
396 			pfn = round_down(pfn + PAGES_PER_SECTION,
397 					 PAGES_PER_SECTION) - 1;
398 			continue;
399 		}
400 
401 		page_nid = get_nid_for_pfn(pfn);
402 		if (page_nid < 0)
403 			continue;
404 		if (page_nid != nid)
405 			continue;
406 		ret = sysfs_create_link_nowarn(&node_devices[nid]->dev.kobj,
407 					&mem_blk->dev.kobj,
408 					kobject_name(&mem_blk->dev.kobj));
409 		if (ret)
410 			return ret;
411 
412 		return sysfs_create_link_nowarn(&mem_blk->dev.kobj,
413 				&node_devices[nid]->dev.kobj,
414 				kobject_name(&node_devices[nid]->dev.kobj));
415 	}
416 	/* mem section does not span the specified node */
417 	return 0;
418 }
419 
420 /* unregister memory section under all nodes that it spans */
unregister_mem_sect_under_nodes(struct memory_block * mem_blk,unsigned long phys_index)421 int unregister_mem_sect_under_nodes(struct memory_block *mem_blk,
422 				    unsigned long phys_index)
423 {
424 	NODEMASK_ALLOC(nodemask_t, unlinked_nodes, GFP_KERNEL);
425 	unsigned long pfn, sect_start_pfn, sect_end_pfn;
426 
427 	if (!mem_blk) {
428 		NODEMASK_FREE(unlinked_nodes);
429 		return -EFAULT;
430 	}
431 	if (!unlinked_nodes)
432 		return -ENOMEM;
433 	nodes_clear(*unlinked_nodes);
434 
435 	sect_start_pfn = section_nr_to_pfn(phys_index);
436 	sect_end_pfn = sect_start_pfn + PAGES_PER_SECTION - 1;
437 	for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
438 		int nid;
439 
440 		nid = get_nid_for_pfn(pfn);
441 		if (nid < 0)
442 			continue;
443 		if (!node_online(nid))
444 			continue;
445 		if (node_test_and_set(nid, *unlinked_nodes))
446 			continue;
447 		sysfs_remove_link(&node_devices[nid]->dev.kobj,
448 			 kobject_name(&mem_blk->dev.kobj));
449 		sysfs_remove_link(&mem_blk->dev.kobj,
450 			 kobject_name(&node_devices[nid]->dev.kobj));
451 	}
452 	NODEMASK_FREE(unlinked_nodes);
453 	return 0;
454 }
455 
link_mem_sections(int nid)456 static int link_mem_sections(int nid)
457 {
458 	unsigned long start_pfn = NODE_DATA(nid)->node_start_pfn;
459 	unsigned long end_pfn = start_pfn + NODE_DATA(nid)->node_spanned_pages;
460 	unsigned long pfn;
461 	struct memory_block *mem_blk = NULL;
462 	int err = 0;
463 
464 	for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
465 		unsigned long section_nr = pfn_to_section_nr(pfn);
466 		struct mem_section *mem_sect;
467 		int ret;
468 
469 		if (!present_section_nr(section_nr))
470 			continue;
471 		mem_sect = __nr_to_section(section_nr);
472 
473 		/* same memblock ? */
474 		if (mem_blk)
475 			if ((section_nr >= mem_blk->start_section_nr) &&
476 			    (section_nr <= mem_blk->end_section_nr))
477 				continue;
478 
479 		mem_blk = find_memory_block_hinted(mem_sect, mem_blk);
480 
481 		ret = register_mem_sect_under_node(mem_blk, nid);
482 		if (!err)
483 			err = ret;
484 
485 		/* discard ref obtained in find_memory_block() */
486 	}
487 
488 	if (mem_blk)
489 		kobject_put(&mem_blk->dev.kobj);
490 	return err;
491 }
492 
493 #ifdef CONFIG_HUGETLBFS
494 /*
495  * Handle per node hstate attribute [un]registration on transistions
496  * to/from memoryless state.
497  */
node_hugetlb_work(struct work_struct * work)498 static void node_hugetlb_work(struct work_struct *work)
499 {
500 	struct node *node = container_of(work, struct node, node_work);
501 
502 	/*
503 	 * We only get here when a node transitions to/from memoryless state.
504 	 * We can detect which transition occurred by examining whether the
505 	 * node has memory now.  hugetlb_register_node() already check this
506 	 * so we try to register the attributes.  If that fails, then the
507 	 * node has transitioned to memoryless, try to unregister the
508 	 * attributes.
509 	 */
510 	if (!hugetlb_register_node(node))
511 		hugetlb_unregister_node(node);
512 }
513 
init_node_hugetlb_work(int nid)514 static void init_node_hugetlb_work(int nid)
515 {
516 	INIT_WORK(&node_devices[nid]->node_work, node_hugetlb_work);
517 }
518 
node_memory_callback(struct notifier_block * self,unsigned long action,void * arg)519 static int node_memory_callback(struct notifier_block *self,
520 				unsigned long action, void *arg)
521 {
522 	struct memory_notify *mnb = arg;
523 	int nid = mnb->status_change_nid;
524 
525 	switch (action) {
526 	case MEM_ONLINE:
527 	case MEM_OFFLINE:
528 		/*
529 		 * offload per node hstate [un]registration to a work thread
530 		 * when transitioning to/from memoryless state.
531 		 */
532 		if (nid != NUMA_NO_NODE)
533 			schedule_work(&node_devices[nid]->node_work);
534 		break;
535 
536 	case MEM_GOING_ONLINE:
537 	case MEM_GOING_OFFLINE:
538 	case MEM_CANCEL_ONLINE:
539 	case MEM_CANCEL_OFFLINE:
540 	default:
541 		break;
542 	}
543 
544 	return NOTIFY_OK;
545 }
546 #endif	/* CONFIG_HUGETLBFS */
547 #else	/* !CONFIG_MEMORY_HOTPLUG_SPARSE */
548 
link_mem_sections(int nid)549 static int link_mem_sections(int nid) { return 0; }
550 #endif	/* CONFIG_MEMORY_HOTPLUG_SPARSE */
551 
552 #if !defined(CONFIG_MEMORY_HOTPLUG_SPARSE) || \
553     !defined(CONFIG_HUGETLBFS)
node_memory_callback(struct notifier_block * self,unsigned long action,void * arg)554 static inline int node_memory_callback(struct notifier_block *self,
555 				unsigned long action, void *arg)
556 {
557 	return NOTIFY_OK;
558 }
559 
init_node_hugetlb_work(int nid)560 static void init_node_hugetlb_work(int nid) { }
561 
562 #endif
563 
register_one_node(int nid)564 int register_one_node(int nid)
565 {
566 	int error = 0;
567 	int cpu;
568 
569 	if (node_online(nid)) {
570 		int p_node = parent_node(nid);
571 		struct node *parent = NULL;
572 
573 		if (p_node != nid)
574 			parent = node_devices[p_node];
575 
576 		node_devices[nid] = kzalloc(sizeof(struct node), GFP_KERNEL);
577 		if (!node_devices[nid])
578 			return -ENOMEM;
579 
580 		error = register_node(node_devices[nid], nid, parent);
581 
582 		/* link cpu under this node */
583 		for_each_present_cpu(cpu) {
584 			if (cpu_to_node(cpu) == nid)
585 				register_cpu_under_node(cpu, nid);
586 		}
587 
588 		/* link memory sections under this node */
589 		error = link_mem_sections(nid);
590 
591 		/* initialize work queue for memory hot plug */
592 		init_node_hugetlb_work(nid);
593 	}
594 
595 	return error;
596 
597 }
598 
unregister_one_node(int nid)599 void unregister_one_node(int nid)
600 {
601 	if (!node_devices[nid])
602 		return;
603 
604 	unregister_node(node_devices[nid]);
605 	node_devices[nid] = NULL;
606 }
607 
608 /*
609  * node states attributes
610  */
611 
print_nodes_state(enum node_states state,char * buf)612 static ssize_t print_nodes_state(enum node_states state, char *buf)
613 {
614 	int n;
615 
616 	n = scnprintf(buf, PAGE_SIZE - 1, "%*pbl",
617 		      nodemask_pr_args(&node_states[state]));
618 	buf[n++] = '\n';
619 	buf[n] = '\0';
620 	return n;
621 }
622 
623 struct node_attr {
624 	struct device_attribute attr;
625 	enum node_states state;
626 };
627 
show_node_state(struct device * dev,struct device_attribute * attr,char * buf)628 static ssize_t show_node_state(struct device *dev,
629 			       struct device_attribute *attr, char *buf)
630 {
631 	struct node_attr *na = container_of(attr, struct node_attr, attr);
632 	return print_nodes_state(na->state, buf);
633 }
634 
635 #define _NODE_ATTR(name, state) \
636 	{ __ATTR(name, 0444, show_node_state, NULL), state }
637 
638 static struct node_attr node_state_attr[] = {
639 	[N_POSSIBLE] = _NODE_ATTR(possible, N_POSSIBLE),
640 	[N_ONLINE] = _NODE_ATTR(online, N_ONLINE),
641 	[N_NORMAL_MEMORY] = _NODE_ATTR(has_normal_memory, N_NORMAL_MEMORY),
642 #ifdef CONFIG_HIGHMEM
643 	[N_HIGH_MEMORY] = _NODE_ATTR(has_high_memory, N_HIGH_MEMORY),
644 #endif
645 #ifdef CONFIG_MOVABLE_NODE
646 	[N_MEMORY] = _NODE_ATTR(has_memory, N_MEMORY),
647 #endif
648 	[N_CPU] = _NODE_ATTR(has_cpu, N_CPU),
649 };
650 
651 static struct attribute *node_state_attrs[] = {
652 	&node_state_attr[N_POSSIBLE].attr.attr,
653 	&node_state_attr[N_ONLINE].attr.attr,
654 	&node_state_attr[N_NORMAL_MEMORY].attr.attr,
655 #ifdef CONFIG_HIGHMEM
656 	&node_state_attr[N_HIGH_MEMORY].attr.attr,
657 #endif
658 #ifdef CONFIG_MOVABLE_NODE
659 	&node_state_attr[N_MEMORY].attr.attr,
660 #endif
661 	&node_state_attr[N_CPU].attr.attr,
662 	NULL
663 };
664 
665 static struct attribute_group memory_root_attr_group = {
666 	.attrs = node_state_attrs,
667 };
668 
669 static const struct attribute_group *cpu_root_attr_groups[] = {
670 	&memory_root_attr_group,
671 	NULL,
672 };
673 
674 #define NODE_CALLBACK_PRI	2	/* lower than SLAB */
register_node_type(void)675 static int __init register_node_type(void)
676 {
677 	int ret;
678 
679  	BUILD_BUG_ON(ARRAY_SIZE(node_state_attr) != NR_NODE_STATES);
680  	BUILD_BUG_ON(ARRAY_SIZE(node_state_attrs)-1 != NR_NODE_STATES);
681 
682 	ret = subsys_system_register(&node_subsys, cpu_root_attr_groups);
683 	if (!ret) {
684 		static struct notifier_block node_memory_callback_nb = {
685 			.notifier_call = node_memory_callback,
686 			.priority = NODE_CALLBACK_PRI,
687 		};
688 		register_hotmemory_notifier(&node_memory_callback_nb);
689 	}
690 
691 	/*
692 	 * Note:  we're not going to unregister the node class if we fail
693 	 * to register the node state class attribute files.
694 	 */
695 	return ret;
696 }
697 postcore_initcall(register_node_type);
698