Root/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/node.h>
11#include <linux/hugetlb.h>
12#include <linux/compaction.h>
13#include <linux/cpumask.h>
14#include <linux/topology.h>
15#include <linux/nodemask.h>
16#include <linux/cpu.h>
17#include <linux/device.h>
18#include <linux/swap.h>
19#include <linux/slab.h>
20
21static struct bus_type node_subsys = {
22    .name = "node",
23    .dev_name = "node",
24};
25
26
27static ssize_t node_read_cpumap(struct device *dev, int type, char *buf)
28{
29    struct node *node_dev = to_node(dev);
30    const struct cpumask *mask = cpumask_of_node(node_dev->dev.id);
31    int len;
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    len = type?
37        cpulist_scnprintf(buf, PAGE_SIZE-2, mask) :
38        cpumask_scnprintf(buf, PAGE_SIZE-2, mask);
39     buf[len++] = '\n';
40     buf[len] = '\0';
41    return len;
42}
43
44static inline ssize_t node_read_cpumask(struct device *dev,
45                struct device_attribute *attr, char *buf)
46{
47    return node_read_cpumap(dev, 0, buf);
48}
49static inline ssize_t node_read_cpulist(struct device *dev,
50                struct device_attribute *attr, char *buf)
51{
52    return node_read_cpumap(dev, 1, buf);
53}
54
55static DEVICE_ATTR(cpumap, S_IRUGO, node_read_cpumask, NULL);
56static DEVICE_ATTR(cpulist, S_IRUGO, node_read_cpulist, NULL);
57
58#define K(x) ((x) << (PAGE_SHIFT - 10))
59static ssize_t node_read_meminfo(struct device *dev,
60            struct device_attribute *attr, char *buf)
61{
62    int n;
63    int nid = dev->id;
64    struct sysinfo i;
65
66    si_meminfo_node(&i, nid);
67    n = sprintf(buf,
68               "Node %d MemTotal: %8lu kB\n"
69               "Node %d MemFree: %8lu kB\n"
70               "Node %d MemUsed: %8lu kB\n"
71               "Node %d Active: %8lu kB\n"
72               "Node %d Inactive: %8lu kB\n"
73               "Node %d Active(anon): %8lu kB\n"
74               "Node %d Inactive(anon): %8lu kB\n"
75               "Node %d Active(file): %8lu kB\n"
76               "Node %d Inactive(file): %8lu kB\n"
77               "Node %d Unevictable: %8lu kB\n"
78               "Node %d Mlocked: %8lu kB\n",
79               nid, K(i.totalram),
80               nid, K(i.freeram),
81               nid, K(i.totalram - i.freeram),
82               nid, K(node_page_state(nid, NR_ACTIVE_ANON) +
83                node_page_state(nid, NR_ACTIVE_FILE)),
84               nid, K(node_page_state(nid, NR_INACTIVE_ANON) +
85                node_page_state(nid, NR_INACTIVE_FILE)),
86               nid, K(node_page_state(nid, NR_ACTIVE_ANON)),
87               nid, K(node_page_state(nid, NR_INACTIVE_ANON)),
88               nid, K(node_page_state(nid, NR_ACTIVE_FILE)),
89               nid, K(node_page_state(nid, NR_INACTIVE_FILE)),
90               nid, K(node_page_state(nid, NR_UNEVICTABLE)),
91               nid, K(node_page_state(nid, NR_MLOCK)));
92
93#ifdef CONFIG_HIGHMEM
94    n += sprintf(buf + n,
95               "Node %d HighTotal: %8lu kB\n"
96               "Node %d HighFree: %8lu kB\n"
97               "Node %d LowTotal: %8lu kB\n"
98               "Node %d LowFree: %8lu kB\n",
99               nid, K(i.totalhigh),
100               nid, K(i.freehigh),
101               nid, K(i.totalram - i.totalhigh),
102               nid, K(i.freeram - i.freehigh));
103#endif
104    n += sprintf(buf + n,
105               "Node %d Dirty: %8lu kB\n"
106               "Node %d Writeback: %8lu kB\n"
107               "Node %d FilePages: %8lu kB\n"
108               "Node %d Mapped: %8lu kB\n"
109               "Node %d AnonPages: %8lu kB\n"
110               "Node %d Shmem: %8lu kB\n"
111               "Node %d KernelStack: %8lu kB\n"
112               "Node %d PageTables: %8lu kB\n"
113               "Node %d NFS_Unstable: %8lu kB\n"
114               "Node %d Bounce: %8lu kB\n"
115               "Node %d WritebackTmp: %8lu kB\n"
116               "Node %d Slab: %8lu kB\n"
117               "Node %d SReclaimable: %8lu kB\n"
118               "Node %d SUnreclaim: %8lu kB\n"
119#ifdef CONFIG_TRANSPARENT_HUGEPAGE
120               "Node %d AnonHugePages: %8lu kB\n"
121#endif
122            ,
123               nid, K(node_page_state(nid, NR_FILE_DIRTY)),
124               nid, K(node_page_state(nid, NR_WRITEBACK)),
125               nid, K(node_page_state(nid, NR_FILE_PAGES)),
126               nid, K(node_page_state(nid, NR_FILE_MAPPED)),
127#ifdef CONFIG_TRANSPARENT_HUGEPAGE
128               nid, K(node_page_state(nid, NR_ANON_PAGES)
129            + node_page_state(nid, NR_ANON_TRANSPARENT_HUGEPAGES) *
130            HPAGE_PMD_NR),
131#else
132               nid, K(node_page_state(nid, NR_ANON_PAGES)),
133#endif
134               nid, K(node_page_state(nid, NR_SHMEM)),
135               nid, node_page_state(nid, NR_KERNEL_STACK) *
136                THREAD_SIZE / 1024,
137               nid, K(node_page_state(nid, NR_PAGETABLE)),
138               nid, K(node_page_state(nid, NR_UNSTABLE_NFS)),
139               nid, K(node_page_state(nid, NR_BOUNCE)),
140               nid, K(node_page_state(nid, NR_WRITEBACK_TEMP)),
141               nid, K(node_page_state(nid, NR_SLAB_RECLAIMABLE) +
142                node_page_state(nid, NR_SLAB_UNRECLAIMABLE)),
143               nid, K(node_page_state(nid, NR_SLAB_RECLAIMABLE)),
144#ifdef CONFIG_TRANSPARENT_HUGEPAGE
145               nid, K(node_page_state(nid, NR_SLAB_UNRECLAIMABLE))
146            , nid,
147            K(node_page_state(nid, NR_ANON_TRANSPARENT_HUGEPAGES) *
148            HPAGE_PMD_NR));
149#else
150               nid, K(node_page_state(nid, NR_SLAB_UNRECLAIMABLE)));
151#endif
152    n += hugetlb_report_node_meminfo(nid, buf + n);
153    return n;
154}
155
156#undef K
157static DEVICE_ATTR(meminfo, S_IRUGO, node_read_meminfo, NULL);
158
159static ssize_t node_read_numastat(struct device *dev,
160                struct device_attribute *attr, char *buf)
161{
162    return sprintf(buf,
163               "numa_hit %lu\n"
164               "numa_miss %lu\n"
165               "numa_foreign %lu\n"
166               "interleave_hit %lu\n"
167               "local_node %lu\n"
168               "other_node %lu\n",
169               node_page_state(dev->id, NUMA_HIT),
170               node_page_state(dev->id, NUMA_MISS),
171               node_page_state(dev->id, NUMA_FOREIGN),
172               node_page_state(dev->id, NUMA_INTERLEAVE_HIT),
173               node_page_state(dev->id, NUMA_LOCAL),
174               node_page_state(dev->id, NUMA_OTHER));
175}
176static DEVICE_ATTR(numastat, S_IRUGO, node_read_numastat, NULL);
177
178static ssize_t node_read_vmstat(struct device *dev,
179                struct device_attribute *attr, char *buf)
180{
181    int nid = dev->id;
182    int i;
183    int n = 0;
184
185    for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
186        n += sprintf(buf+n, "%s %lu\n", vmstat_text[i],
187                 node_page_state(nid, i));
188
189    return n;
190}
191static DEVICE_ATTR(vmstat, S_IRUGO, node_read_vmstat, NULL);
192
193static ssize_t node_read_distance(struct device *dev,
194            struct device_attribute *attr, char * buf)
195{
196    int nid = dev->id;
197    int len = 0;
198    int i;
199
200    /*
201     * buf is currently PAGE_SIZE in length and each node needs 4 chars
202     * at the most (distance + space or newline).
203     */
204    BUILD_BUG_ON(MAX_NUMNODES * 4 > PAGE_SIZE);
205
206    for_each_online_node(i)
207        len += sprintf(buf + len, "%s%d", i ? " " : "", node_distance(nid, i));
208
209    len += sprintf(buf + len, "\n");
210    return len;
211}
212static DEVICE_ATTR(distance, S_IRUGO, node_read_distance, NULL);
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 */
224static node_registration_func_t __hugetlb_register_node;
225static node_registration_func_t __hugetlb_unregister_node;
226
227static 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
237static inline void hugetlb_unregister_node(struct node *node)
238{
239    if (__hugetlb_unregister_node)
240        __hugetlb_unregister_node(node);
241}
242
243void 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
250static inline void hugetlb_register_node(struct node *node) {}
251
252static inline void hugetlb_unregister_node(struct node *node) {}
253#endif
254
255static 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 */
280static 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    error = device_register(&node->dev);
288
289    if (!error){
290        device_create_file(&node->dev, &dev_attr_cpumap);
291        device_create_file(&node->dev, &dev_attr_cpulist);
292        device_create_file(&node->dev, &dev_attr_meminfo);
293        device_create_file(&node->dev, &dev_attr_numastat);
294        device_create_file(&node->dev, &dev_attr_distance);
295        device_create_file(&node->dev, &dev_attr_vmstat);
296
297        scan_unevictable_register_node(node);
298
299        hugetlb_register_node(node);
300
301        compaction_register_node(node);
302    }
303    return error;
304}
305
306/**
307 * unregister_node - unregister a node device
308 * @node: node going away
309 *
310 * Unregisters a node device @node. All the devices on the node must be
311 * unregistered before calling this function.
312 */
313void unregister_node(struct node *node)
314{
315    device_remove_file(&node->dev, &dev_attr_cpumap);
316    device_remove_file(&node->dev, &dev_attr_cpulist);
317    device_remove_file(&node->dev, &dev_attr_meminfo);
318    device_remove_file(&node->dev, &dev_attr_numastat);
319    device_remove_file(&node->dev, &dev_attr_distance);
320    device_remove_file(&node->dev, &dev_attr_vmstat);
321
322    scan_unevictable_unregister_node(node);
323    hugetlb_unregister_node(node); /* no-op, if memoryless node */
324
325    device_unregister(&node->dev);
326}
327
328struct node *node_devices[MAX_NUMNODES];
329
330/*
331 * register cpu under node
332 */
333int register_cpu_under_node(unsigned int cpu, unsigned int nid)
334{
335    int ret;
336    struct device *obj;
337
338    if (!node_online(nid))
339        return 0;
340
341    obj = get_cpu_device(cpu);
342    if (!obj)
343        return 0;
344
345    ret = sysfs_create_link(&node_devices[nid]->dev.kobj,
346                &obj->kobj,
347                kobject_name(&obj->kobj));
348    if (ret)
349        return ret;
350
351    return sysfs_create_link(&obj->kobj,
352                 &node_devices[nid]->dev.kobj,
353                 kobject_name(&node_devices[nid]->dev.kobj));
354}
355
356int unregister_cpu_under_node(unsigned int cpu, unsigned int nid)
357{
358    struct device *obj;
359
360    if (!node_online(nid))
361        return 0;
362
363    obj = get_cpu_device(cpu);
364    if (!obj)
365        return 0;
366
367    sysfs_remove_link(&node_devices[nid]->dev.kobj,
368              kobject_name(&obj->kobj));
369    sysfs_remove_link(&obj->kobj,
370              kobject_name(&node_devices[nid]->dev.kobj));
371
372    return 0;
373}
374
375#ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
376#define page_initialized(page) (page->lru.next)
377
378static int get_nid_for_pfn(unsigned long pfn)
379{
380    struct page *page;
381
382    if (!pfn_valid_within(pfn))
383        return -1;
384    page = pfn_to_page(pfn);
385    if (!page_initialized(page))
386        return -1;
387    return pfn_to_nid(pfn);
388}
389
390/* register memory section under specified node if it spans that node */
391int register_mem_sect_under_node(struct memory_block *mem_blk, int nid)
392{
393    int ret;
394    unsigned long pfn, sect_start_pfn, sect_end_pfn;
395
396    if (!mem_blk)
397        return -EFAULT;
398    if (!node_online(nid))
399        return 0;
400
401    sect_start_pfn = section_nr_to_pfn(mem_blk->start_section_nr);
402    sect_end_pfn = section_nr_to_pfn(mem_blk->end_section_nr);
403    sect_end_pfn += PAGES_PER_SECTION - 1;
404    for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
405        int page_nid;
406
407        page_nid = get_nid_for_pfn(pfn);
408        if (page_nid < 0)
409            continue;
410        if (page_nid != nid)
411            continue;
412        ret = sysfs_create_link_nowarn(&node_devices[nid]->dev.kobj,
413                    &mem_blk->dev.kobj,
414                    kobject_name(&mem_blk->dev.kobj));
415        if (ret)
416            return ret;
417
418        return sysfs_create_link_nowarn(&mem_blk->dev.kobj,
419                &node_devices[nid]->dev.kobj,
420                kobject_name(&node_devices[nid]->dev.kobj));
421    }
422    /* mem section does not span the specified node */
423    return 0;
424}
425
426/* unregister memory section under all nodes that it spans */
427int unregister_mem_sect_under_nodes(struct memory_block *mem_blk,
428                    unsigned long phys_index)
429{
430    NODEMASK_ALLOC(nodemask_t, unlinked_nodes, GFP_KERNEL);
431    unsigned long pfn, sect_start_pfn, sect_end_pfn;
432
433    if (!mem_blk) {
434        NODEMASK_FREE(unlinked_nodes);
435        return -EFAULT;
436    }
437    if (!unlinked_nodes)
438        return -ENOMEM;
439    nodes_clear(*unlinked_nodes);
440
441    sect_start_pfn = section_nr_to_pfn(phys_index);
442    sect_end_pfn = sect_start_pfn + PAGES_PER_SECTION - 1;
443    for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
444        int nid;
445
446        nid = get_nid_for_pfn(pfn);
447        if (nid < 0)
448            continue;
449        if (!node_online(nid))
450            continue;
451        if (node_test_and_set(nid, *unlinked_nodes))
452            continue;
453        sysfs_remove_link(&node_devices[nid]->dev.kobj,
454             kobject_name(&mem_blk->dev.kobj));
455        sysfs_remove_link(&mem_blk->dev.kobj,
456             kobject_name(&node_devices[nid]->dev.kobj));
457    }
458    NODEMASK_FREE(unlinked_nodes);
459    return 0;
460}
461
462static int link_mem_sections(int nid)
463{
464    unsigned long start_pfn = NODE_DATA(nid)->node_start_pfn;
465    unsigned long end_pfn = start_pfn + NODE_DATA(nid)->node_spanned_pages;
466    unsigned long pfn;
467    struct memory_block *mem_blk = NULL;
468    int err = 0;
469
470    for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
471        unsigned long section_nr = pfn_to_section_nr(pfn);
472        struct mem_section *mem_sect;
473        int ret;
474
475        if (!present_section_nr(section_nr))
476            continue;
477        mem_sect = __nr_to_section(section_nr);
478
479        /* same memblock ? */
480        if (mem_blk)
481            if ((section_nr >= mem_blk->start_section_nr) &&
482                (section_nr <= mem_blk->end_section_nr))
483                continue;
484
485        mem_blk = find_memory_block_hinted(mem_sect, mem_blk);
486
487        ret = register_mem_sect_under_node(mem_blk, nid);
488        if (!err)
489            err = ret;
490
491        /* discard ref obtained in find_memory_block() */
492    }
493
494    if (mem_blk)
495        kobject_put(&mem_blk->dev.kobj);
496    return err;
497}
498
499#ifdef CONFIG_HUGETLBFS
500/*
501 * Handle per node hstate attribute [un]registration on transistions
502 * to/from memoryless state.
503 */
504static void node_hugetlb_work(struct work_struct *work)
505{
506    struct node *node = container_of(work, struct node, node_work);
507
508    /*
509     * We only get here when a node transitions to/from memoryless state.
510     * We can detect which transition occurred by examining whether the
511     * node has memory now. hugetlb_register_node() already check this
512     * so we try to register the attributes. If that fails, then the
513     * node has transitioned to memoryless, try to unregister the
514     * attributes.
515     */
516    if (!hugetlb_register_node(node))
517        hugetlb_unregister_node(node);
518}
519
520static void init_node_hugetlb_work(int nid)
521{
522    INIT_WORK(&node_devices[nid]->node_work, node_hugetlb_work);
523}
524
525static int node_memory_callback(struct notifier_block *self,
526                unsigned long action, void *arg)
527{
528    struct memory_notify *mnb = arg;
529    int nid = mnb->status_change_nid;
530
531    switch (action) {
532    case MEM_ONLINE:
533    case MEM_OFFLINE:
534        /*
535         * offload per node hstate [un]registration to a work thread
536         * when transitioning to/from memoryless state.
537         */
538        if (nid != NUMA_NO_NODE)
539            schedule_work(&node_devices[nid]->node_work);
540        break;
541
542    case MEM_GOING_ONLINE:
543    case MEM_GOING_OFFLINE:
544    case MEM_CANCEL_ONLINE:
545    case MEM_CANCEL_OFFLINE:
546    default:
547        break;
548    }
549
550    return NOTIFY_OK;
551}
552#endif /* CONFIG_HUGETLBFS */
553#else /* !CONFIG_MEMORY_HOTPLUG_SPARSE */
554
555static int link_mem_sections(int nid) { return 0; }
556#endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
557
558#if !defined(CONFIG_MEMORY_HOTPLUG_SPARSE) || \
559    !defined(CONFIG_HUGETLBFS)
560static inline int node_memory_callback(struct notifier_block *self,
561                unsigned long action, void *arg)
562{
563    return NOTIFY_OK;
564}
565
566static void init_node_hugetlb_work(int nid) { }
567
568#endif
569
570int register_one_node(int nid)
571{
572    int error = 0;
573    int cpu;
574
575    if (node_online(nid)) {
576        int p_node = parent_node(nid);
577        struct node *parent = NULL;
578
579        if (p_node != nid)
580            parent = node_devices[p_node];
581
582        node_devices[nid] = kzalloc(sizeof(struct node), GFP_KERNEL);
583        if (!node_devices[nid])
584            return -ENOMEM;
585
586        error = register_node(node_devices[nid], nid, parent);
587
588        /* link cpu under this node */
589        for_each_present_cpu(cpu) {
590            if (cpu_to_node(cpu) == nid)
591                register_cpu_under_node(cpu, nid);
592        }
593
594        /* link memory sections under this node */
595        error = link_mem_sections(nid);
596
597        /* initialize work queue for memory hot plug */
598        init_node_hugetlb_work(nid);
599    }
600
601    return error;
602
603}
604
605void unregister_one_node(int nid)
606{
607    unregister_node(node_devices[nid]);
608    node_devices[nid] = NULL;
609}
610
611/*
612 * node states attributes
613 */
614
615static ssize_t print_nodes_state(enum node_states state, char *buf)
616{
617    int n;
618
619    n = nodelist_scnprintf(buf, PAGE_SIZE-2, node_states[state]);
620    buf[n++] = '\n';
621    buf[n] = '\0';
622    return n;
623}
624
625struct node_attr {
626    struct device_attribute attr;
627    enum node_states state;
628};
629
630static ssize_t show_node_state(struct device *dev,
631                   struct device_attribute *attr, char *buf)
632{
633    struct node_attr *na = container_of(attr, struct node_attr, attr);
634    return print_nodes_state(na->state, buf);
635}
636
637#define _NODE_ATTR(name, state) \
638    { __ATTR(name, 0444, show_node_state, NULL), state }
639
640static struct node_attr node_state_attr[] = {
641    [N_POSSIBLE] = _NODE_ATTR(possible, N_POSSIBLE),
642    [N_ONLINE] = _NODE_ATTR(online, N_ONLINE),
643    [N_NORMAL_MEMORY] = _NODE_ATTR(has_normal_memory, N_NORMAL_MEMORY),
644#ifdef CONFIG_HIGHMEM
645    [N_HIGH_MEMORY] = _NODE_ATTR(has_high_memory, N_HIGH_MEMORY),
646#endif
647#ifdef CONFIG_MOVABLE_NODE
648    [N_MEMORY] = _NODE_ATTR(has_memory, N_MEMORY),
649#endif
650    [N_CPU] = _NODE_ATTR(has_cpu, N_CPU),
651};
652
653static struct attribute *node_state_attrs[] = {
654    &node_state_attr[N_POSSIBLE].attr.attr,
655    &node_state_attr[N_ONLINE].attr.attr,
656    &node_state_attr[N_NORMAL_MEMORY].attr.attr,
657#ifdef CONFIG_HIGHMEM
658    &node_state_attr[N_HIGH_MEMORY].attr.attr,
659#endif
660#ifdef CONFIG_MOVABLE_NODE
661    &node_state_attr[N_MEMORY].attr.attr,
662#endif
663    &node_state_attr[N_CPU].attr.attr,
664    NULL
665};
666
667static struct attribute_group memory_root_attr_group = {
668    .attrs = node_state_attrs,
669};
670
671static const struct attribute_group *cpu_root_attr_groups[] = {
672    &memory_root_attr_group,
673    NULL,
674};
675
676#define NODE_CALLBACK_PRI 2 /* lower than SLAB */
677static int __init register_node_type(void)
678{
679    int ret;
680
681     BUILD_BUG_ON(ARRAY_SIZE(node_state_attr) != NR_NODE_STATES);
682     BUILD_BUG_ON(ARRAY_SIZE(node_state_attrs)-1 != NR_NODE_STATES);
683
684    ret = subsys_system_register(&node_subsys, cpu_root_attr_groups);
685    if (!ret) {
686        hotplug_memory_notifier(node_memory_callback,
687                    NODE_CALLBACK_PRI);
688    }
689
690    /*
691     * Note: we're not going to unregister the node class if we fail
692     * to register the node state class attribute files.
693     */
694    return ret;
695}
696postcore_initcall(register_node_type);
697

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