[MIPS] Use common definitions from asm-generic/signal.h
[linux-2.6/linux-mips/linux-dm7025.git] / arch / powerpc / mm / numa.c
blob6c0f1c7d83e502bf86bb14b567c91d09125a6a3e
1 /*
2 * pSeries NUMA support
4 * Copyright (C) 2002 Anton Blanchard <anton@au.ibm.com>, IBM
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
11 #include <linux/threads.h>
12 #include <linux/bootmem.h>
13 #include <linux/init.h>
14 #include <linux/mm.h>
15 #include <linux/mmzone.h>
16 #include <linux/module.h>
17 #include <linux/nodemask.h>
18 #include <linux/cpu.h>
19 #include <linux/notifier.h>
20 #include <asm/sparsemem.h>
21 #include <asm/lmb.h>
22 #include <asm/system.h>
23 #include <asm/smp.h>
25 static int numa_enabled = 1;
27 static int numa_debug;
28 #define dbg(args...) if (numa_debug) { printk(KERN_INFO args); }
30 int numa_cpu_lookup_table[NR_CPUS];
31 cpumask_t numa_cpumask_lookup_table[MAX_NUMNODES];
32 struct pglist_data *node_data[MAX_NUMNODES];
34 EXPORT_SYMBOL(numa_cpu_lookup_table);
35 EXPORT_SYMBOL(numa_cpumask_lookup_table);
36 EXPORT_SYMBOL(node_data);
38 static bootmem_data_t __initdata plat_node_bdata[MAX_NUMNODES];
39 static int min_common_depth;
40 static int n_mem_addr_cells, n_mem_size_cells;
43 * We need somewhere to store start/end/node for each region until we have
44 * allocated the real node_data structures.
46 #define MAX_REGIONS (MAX_LMB_REGIONS*2)
47 static struct {
48 unsigned long start_pfn;
49 unsigned long end_pfn;
50 int nid;
51 } init_node_data[MAX_REGIONS] __initdata;
53 int __init early_pfn_to_nid(unsigned long pfn)
55 unsigned int i;
57 for (i = 0; init_node_data[i].end_pfn; i++) {
58 unsigned long start_pfn = init_node_data[i].start_pfn;
59 unsigned long end_pfn = init_node_data[i].end_pfn;
61 if ((start_pfn <= pfn) && (pfn < end_pfn))
62 return init_node_data[i].nid;
65 return -1;
68 void __init add_region(unsigned int nid, unsigned long start_pfn,
69 unsigned long pages)
71 unsigned int i;
73 dbg("add_region nid %d start_pfn 0x%lx pages 0x%lx\n",
74 nid, start_pfn, pages);
76 for (i = 0; init_node_data[i].end_pfn; i++) {
77 if (init_node_data[i].nid != nid)
78 continue;
79 if (init_node_data[i].end_pfn == start_pfn) {
80 init_node_data[i].end_pfn += pages;
81 return;
83 if (init_node_data[i].start_pfn == (start_pfn + pages)) {
84 init_node_data[i].start_pfn -= pages;
85 return;
90 * Leave last entry NULL so we dont iterate off the end (we use
91 * entry.end_pfn to terminate the walk).
93 if (i >= (MAX_REGIONS - 1)) {
94 printk(KERN_ERR "WARNING: too many memory regions in "
95 "numa code, truncating\n");
96 return;
99 init_node_data[i].start_pfn = start_pfn;
100 init_node_data[i].end_pfn = start_pfn + pages;
101 init_node_data[i].nid = nid;
104 /* We assume init_node_data has no overlapping regions */
105 void __init get_region(unsigned int nid, unsigned long *start_pfn,
106 unsigned long *end_pfn, unsigned long *pages_present)
108 unsigned int i;
110 *start_pfn = -1UL;
111 *end_pfn = *pages_present = 0;
113 for (i = 0; init_node_data[i].end_pfn; i++) {
114 if (init_node_data[i].nid != nid)
115 continue;
117 *pages_present += init_node_data[i].end_pfn -
118 init_node_data[i].start_pfn;
120 if (init_node_data[i].start_pfn < *start_pfn)
121 *start_pfn = init_node_data[i].start_pfn;
123 if (init_node_data[i].end_pfn > *end_pfn)
124 *end_pfn = init_node_data[i].end_pfn;
127 /* We didnt find a matching region, return start/end as 0 */
128 if (*start_pfn == -1UL)
129 *start_pfn = 0;
132 static void __cpuinit map_cpu_to_node(int cpu, int node)
134 numa_cpu_lookup_table[cpu] = node;
136 dbg("adding cpu %d to node %d\n", cpu, node);
138 if (!(cpu_isset(cpu, numa_cpumask_lookup_table[node])))
139 cpu_set(cpu, numa_cpumask_lookup_table[node]);
142 #ifdef CONFIG_HOTPLUG_CPU
143 static void unmap_cpu_from_node(unsigned long cpu)
145 int node = numa_cpu_lookup_table[cpu];
147 dbg("removing cpu %lu from node %d\n", cpu, node);
149 if (cpu_isset(cpu, numa_cpumask_lookup_table[node])) {
150 cpu_clear(cpu, numa_cpumask_lookup_table[node]);
151 } else {
152 printk(KERN_ERR "WARNING: cpu %lu not found in node %d\n",
153 cpu, node);
156 #endif /* CONFIG_HOTPLUG_CPU */
158 static struct device_node * __cpuinit find_cpu_node(unsigned int cpu)
160 unsigned int hw_cpuid = get_hard_smp_processor_id(cpu);
161 struct device_node *cpu_node = NULL;
162 const unsigned int *interrupt_server, *reg;
163 int len;
165 while ((cpu_node = of_find_node_by_type(cpu_node, "cpu")) != NULL) {
166 /* Try interrupt server first */
167 interrupt_server = get_property(cpu_node,
168 "ibm,ppc-interrupt-server#s", &len);
170 len = len / sizeof(u32);
172 if (interrupt_server && (len > 0)) {
173 while (len--) {
174 if (interrupt_server[len] == hw_cpuid)
175 return cpu_node;
177 } else {
178 reg = get_property(cpu_node, "reg", &len);
179 if (reg && (len > 0) && (reg[0] == hw_cpuid))
180 return cpu_node;
184 return NULL;
187 /* must hold reference to node during call */
188 static const int *of_get_associativity(struct device_node *dev)
190 return get_property(dev, "ibm,associativity", NULL);
193 /* Returns nid in the range [0..MAX_NUMNODES-1], or -1 if no useful numa
194 * info is found.
196 static int of_node_to_nid_single(struct device_node *device)
198 int nid = -1;
199 const unsigned int *tmp;
201 if (min_common_depth == -1)
202 goto out;
204 tmp = of_get_associativity(device);
205 if (!tmp)
206 goto out;
208 if (tmp[0] >= min_common_depth)
209 nid = tmp[min_common_depth];
211 /* POWER4 LPAR uses 0xffff as invalid node */
212 if (nid == 0xffff || nid >= MAX_NUMNODES)
213 nid = -1;
214 out:
215 return nid;
218 /* Walk the device tree upwards, looking for an associativity id */
219 int of_node_to_nid(struct device_node *device)
221 struct device_node *tmp;
222 int nid = -1;
224 of_node_get(device);
225 while (device) {
226 nid = of_node_to_nid_single(device);
227 if (nid != -1)
228 break;
230 tmp = device;
231 device = of_get_parent(tmp);
232 of_node_put(tmp);
234 of_node_put(device);
236 return nid;
238 EXPORT_SYMBOL_GPL(of_node_to_nid);
241 * In theory, the "ibm,associativity" property may contain multiple
242 * associativity lists because a resource may be multiply connected
243 * into the machine. This resource then has different associativity
244 * characteristics relative to its multiple connections. We ignore
245 * this for now. We also assume that all cpu and memory sets have
246 * their distances represented at a common level. This won't be
247 * true for heirarchical NUMA.
249 * In any case the ibm,associativity-reference-points should give
250 * the correct depth for a normal NUMA system.
252 * - Dave Hansen <haveblue@us.ibm.com>
254 static int __init find_min_common_depth(void)
256 int depth;
257 const unsigned int *ref_points;
258 struct device_node *rtas_root;
259 unsigned int len;
261 rtas_root = of_find_node_by_path("/rtas");
263 if (!rtas_root)
264 return -1;
267 * this property is 2 32-bit integers, each representing a level of
268 * depth in the associativity nodes. The first is for an SMP
269 * configuration (should be all 0's) and the second is for a normal
270 * NUMA configuration.
272 ref_points = get_property(rtas_root,
273 "ibm,associativity-reference-points", &len);
275 if ((len >= 1) && ref_points) {
276 depth = ref_points[1];
277 } else {
278 dbg("NUMA: ibm,associativity-reference-points not found.\n");
279 depth = -1;
281 of_node_put(rtas_root);
283 return depth;
286 static void __init get_n_mem_cells(int *n_addr_cells, int *n_size_cells)
288 struct device_node *memory = NULL;
290 memory = of_find_node_by_type(memory, "memory");
291 if (!memory)
292 panic("numa.c: No memory nodes found!");
294 *n_addr_cells = prom_n_addr_cells(memory);
295 *n_size_cells = prom_n_size_cells(memory);
296 of_node_put(memory);
299 static unsigned long __devinit read_n_cells(int n, const unsigned int **buf)
301 unsigned long result = 0;
303 while (n--) {
304 result = (result << 32) | **buf;
305 (*buf)++;
307 return result;
311 * Figure out to which domain a cpu belongs and stick it there.
312 * Return the id of the domain used.
314 static int __cpuinit numa_setup_cpu(unsigned long lcpu)
316 int nid = 0;
317 struct device_node *cpu = find_cpu_node(lcpu);
319 if (!cpu) {
320 WARN_ON(1);
321 goto out;
324 nid = of_node_to_nid_single(cpu);
326 if (nid < 0 || !node_online(nid))
327 nid = any_online_node(NODE_MASK_ALL);
328 out:
329 map_cpu_to_node(lcpu, nid);
331 of_node_put(cpu);
333 return nid;
336 static int __cpuinit cpu_numa_callback(struct notifier_block *nfb,
337 unsigned long action,
338 void *hcpu)
340 unsigned long lcpu = (unsigned long)hcpu;
341 int ret = NOTIFY_DONE;
343 switch (action) {
344 case CPU_UP_PREPARE:
345 numa_setup_cpu(lcpu);
346 ret = NOTIFY_OK;
347 break;
348 #ifdef CONFIG_HOTPLUG_CPU
349 case CPU_DEAD:
350 case CPU_UP_CANCELED:
351 unmap_cpu_from_node(lcpu);
352 break;
353 ret = NOTIFY_OK;
354 #endif
356 return ret;
360 * Check and possibly modify a memory region to enforce the memory limit.
362 * Returns the size the region should have to enforce the memory limit.
363 * This will either be the original value of size, a truncated value,
364 * or zero. If the returned value of size is 0 the region should be
365 * discarded as it lies wholy above the memory limit.
367 static unsigned long __init numa_enforce_memory_limit(unsigned long start,
368 unsigned long size)
371 * We use lmb_end_of_DRAM() in here instead of memory_limit because
372 * we've already adjusted it for the limit and it takes care of
373 * having memory holes below the limit.
376 if (! memory_limit)
377 return size;
379 if (start + size <= lmb_end_of_DRAM())
380 return size;
382 if (start >= lmb_end_of_DRAM())
383 return 0;
385 return lmb_end_of_DRAM() - start;
388 static int __init parse_numa_properties(void)
390 struct device_node *cpu = NULL;
391 struct device_node *memory = NULL;
392 int default_nid = 0;
393 unsigned long i;
395 if (numa_enabled == 0) {
396 printk(KERN_WARNING "NUMA disabled by user\n");
397 return -1;
400 min_common_depth = find_min_common_depth();
402 if (min_common_depth < 0)
403 return min_common_depth;
405 dbg("NUMA associativity depth for CPU/Memory: %d\n", min_common_depth);
408 * Even though we connect cpus to numa domains later in SMP
409 * init, we need to know the node ids now. This is because
410 * each node to be onlined must have NODE_DATA etc backing it.
412 for_each_present_cpu(i) {
413 int nid;
415 cpu = find_cpu_node(i);
416 BUG_ON(!cpu);
417 nid = of_node_to_nid_single(cpu);
418 of_node_put(cpu);
421 * Don't fall back to default_nid yet -- we will plug
422 * cpus into nodes once the memory scan has discovered
423 * the topology.
425 if (nid < 0)
426 continue;
427 node_set_online(nid);
430 get_n_mem_cells(&n_mem_addr_cells, &n_mem_size_cells);
431 memory = NULL;
432 while ((memory = of_find_node_by_type(memory, "memory")) != NULL) {
433 unsigned long start;
434 unsigned long size;
435 int nid;
436 int ranges;
437 const unsigned int *memcell_buf;
438 unsigned int len;
440 memcell_buf = get_property(memory,
441 "linux,usable-memory", &len);
442 if (!memcell_buf || len <= 0)
443 memcell_buf = get_property(memory, "reg", &len);
444 if (!memcell_buf || len <= 0)
445 continue;
447 /* ranges in cell */
448 ranges = (len >> 2) / (n_mem_addr_cells + n_mem_size_cells);
449 new_range:
450 /* these are order-sensitive, and modify the buffer pointer */
451 start = read_n_cells(n_mem_addr_cells, &memcell_buf);
452 size = read_n_cells(n_mem_size_cells, &memcell_buf);
455 * Assumption: either all memory nodes or none will
456 * have associativity properties. If none, then
457 * everything goes to default_nid.
459 nid = of_node_to_nid_single(memory);
460 if (nid < 0)
461 nid = default_nid;
462 node_set_online(nid);
464 if (!(size = numa_enforce_memory_limit(start, size))) {
465 if (--ranges)
466 goto new_range;
467 else
468 continue;
471 add_region(nid, start >> PAGE_SHIFT,
472 size >> PAGE_SHIFT);
474 if (--ranges)
475 goto new_range;
478 return 0;
481 static void __init setup_nonnuma(void)
483 unsigned long top_of_ram = lmb_end_of_DRAM();
484 unsigned long total_ram = lmb_phys_mem_size();
485 unsigned int i;
487 printk(KERN_DEBUG "Top of RAM: 0x%lx, Total RAM: 0x%lx\n",
488 top_of_ram, total_ram);
489 printk(KERN_DEBUG "Memory hole size: %ldMB\n",
490 (top_of_ram - total_ram) >> 20);
492 for (i = 0; i < lmb.memory.cnt; ++i)
493 add_region(0, lmb.memory.region[i].base >> PAGE_SHIFT,
494 lmb_size_pages(&lmb.memory, i));
495 node_set_online(0);
498 void __init dump_numa_cpu_topology(void)
500 unsigned int node;
501 unsigned int cpu, count;
503 if (min_common_depth == -1 || !numa_enabled)
504 return;
506 for_each_online_node(node) {
507 printk(KERN_DEBUG "Node %d CPUs:", node);
509 count = 0;
511 * If we used a CPU iterator here we would miss printing
512 * the holes in the cpumap.
514 for (cpu = 0; cpu < NR_CPUS; cpu++) {
515 if (cpu_isset(cpu, numa_cpumask_lookup_table[node])) {
516 if (count == 0)
517 printk(" %u", cpu);
518 ++count;
519 } else {
520 if (count > 1)
521 printk("-%u", cpu - 1);
522 count = 0;
526 if (count > 1)
527 printk("-%u", NR_CPUS - 1);
528 printk("\n");
532 static void __init dump_numa_memory_topology(void)
534 unsigned int node;
535 unsigned int count;
537 if (min_common_depth == -1 || !numa_enabled)
538 return;
540 for_each_online_node(node) {
541 unsigned long i;
543 printk(KERN_DEBUG "Node %d Memory:", node);
545 count = 0;
547 for (i = 0; i < lmb_end_of_DRAM();
548 i += (1 << SECTION_SIZE_BITS)) {
549 if (early_pfn_to_nid(i >> PAGE_SHIFT) == node) {
550 if (count == 0)
551 printk(" 0x%lx", i);
552 ++count;
553 } else {
554 if (count > 0)
555 printk("-0x%lx", i);
556 count = 0;
560 if (count > 0)
561 printk("-0x%lx", i);
562 printk("\n");
567 * Allocate some memory, satisfying the lmb or bootmem allocator where
568 * required. nid is the preferred node and end is the physical address of
569 * the highest address in the node.
571 * Returns the physical address of the memory.
573 static void __init *careful_allocation(int nid, unsigned long size,
574 unsigned long align,
575 unsigned long end_pfn)
577 int new_nid;
578 unsigned long ret = __lmb_alloc_base(size, align, end_pfn << PAGE_SHIFT);
580 /* retry over all memory */
581 if (!ret)
582 ret = __lmb_alloc_base(size, align, lmb_end_of_DRAM());
584 if (!ret)
585 panic("numa.c: cannot allocate %lu bytes on node %d",
586 size, nid);
589 * If the memory came from a previously allocated node, we must
590 * retry with the bootmem allocator.
592 new_nid = early_pfn_to_nid(ret >> PAGE_SHIFT);
593 if (new_nid < nid) {
594 ret = (unsigned long)__alloc_bootmem_node(NODE_DATA(new_nid),
595 size, align, 0);
597 if (!ret)
598 panic("numa.c: cannot allocate %lu bytes on node %d",
599 size, new_nid);
601 ret = __pa(ret);
603 dbg("alloc_bootmem %lx %lx\n", ret, size);
606 return (void *)ret;
609 static struct notifier_block __cpuinitdata ppc64_numa_nb = {
610 .notifier_call = cpu_numa_callback,
611 .priority = 1 /* Must run before sched domains notifier. */
614 void __init do_init_bootmem(void)
616 int nid;
617 unsigned int i;
619 min_low_pfn = 0;
620 max_low_pfn = lmb_end_of_DRAM() >> PAGE_SHIFT;
621 max_pfn = max_low_pfn;
623 if (parse_numa_properties())
624 setup_nonnuma();
625 else
626 dump_numa_memory_topology();
628 register_cpu_notifier(&ppc64_numa_nb);
629 cpu_numa_callback(&ppc64_numa_nb, CPU_UP_PREPARE,
630 (void *)(unsigned long)boot_cpuid);
632 for_each_online_node(nid) {
633 unsigned long start_pfn, end_pfn, pages_present;
634 unsigned long bootmem_paddr;
635 unsigned long bootmap_pages;
637 get_region(nid, &start_pfn, &end_pfn, &pages_present);
639 /* Allocate the node structure node local if possible */
640 NODE_DATA(nid) = careful_allocation(nid,
641 sizeof(struct pglist_data),
642 SMP_CACHE_BYTES, end_pfn);
643 NODE_DATA(nid) = __va(NODE_DATA(nid));
644 memset(NODE_DATA(nid), 0, sizeof(struct pglist_data));
646 dbg("node %d\n", nid);
647 dbg("NODE_DATA() = %p\n", NODE_DATA(nid));
649 NODE_DATA(nid)->bdata = &plat_node_bdata[nid];
650 NODE_DATA(nid)->node_start_pfn = start_pfn;
651 NODE_DATA(nid)->node_spanned_pages = end_pfn - start_pfn;
653 if (NODE_DATA(nid)->node_spanned_pages == 0)
654 continue;
656 dbg("start_paddr = %lx\n", start_pfn << PAGE_SHIFT);
657 dbg("end_paddr = %lx\n", end_pfn << PAGE_SHIFT);
659 bootmap_pages = bootmem_bootmap_pages(end_pfn - start_pfn);
660 bootmem_paddr = (unsigned long)careful_allocation(nid,
661 bootmap_pages << PAGE_SHIFT,
662 PAGE_SIZE, end_pfn);
663 memset(__va(bootmem_paddr), 0, bootmap_pages << PAGE_SHIFT);
665 dbg("bootmap_paddr = %lx\n", bootmem_paddr);
667 init_bootmem_node(NODE_DATA(nid), bootmem_paddr >> PAGE_SHIFT,
668 start_pfn, end_pfn);
670 /* Add free regions on this node */
671 for (i = 0; init_node_data[i].end_pfn; i++) {
672 unsigned long start, end;
674 if (init_node_data[i].nid != nid)
675 continue;
677 start = init_node_data[i].start_pfn << PAGE_SHIFT;
678 end = init_node_data[i].end_pfn << PAGE_SHIFT;
680 dbg("free_bootmem %lx %lx\n", start, end - start);
681 free_bootmem_node(NODE_DATA(nid), start, end - start);
684 /* Mark reserved regions on this node */
685 for (i = 0; i < lmb.reserved.cnt; i++) {
686 unsigned long physbase = lmb.reserved.region[i].base;
687 unsigned long size = lmb.reserved.region[i].size;
688 unsigned long start_paddr = start_pfn << PAGE_SHIFT;
689 unsigned long end_paddr = end_pfn << PAGE_SHIFT;
691 if (early_pfn_to_nid(physbase >> PAGE_SHIFT) != nid &&
692 early_pfn_to_nid((physbase+size-1) >> PAGE_SHIFT) != nid)
693 continue;
695 if (physbase < end_paddr &&
696 (physbase+size) > start_paddr) {
697 /* overlaps */
698 if (physbase < start_paddr) {
699 size -= start_paddr - physbase;
700 physbase = start_paddr;
703 if (size > end_paddr - physbase)
704 size = end_paddr - physbase;
706 dbg("reserve_bootmem %lx %lx\n", physbase,
707 size);
708 reserve_bootmem_node(NODE_DATA(nid), physbase,
709 size);
713 /* Add regions into sparsemem */
714 for (i = 0; init_node_data[i].end_pfn; i++) {
715 unsigned long start, end;
717 if (init_node_data[i].nid != nid)
718 continue;
720 start = init_node_data[i].start_pfn;
721 end = init_node_data[i].end_pfn;
723 memory_present(nid, start, end);
728 void __init paging_init(void)
730 unsigned long zones_size[MAX_NR_ZONES];
731 unsigned long zholes_size[MAX_NR_ZONES];
732 int nid;
734 memset(zones_size, 0, sizeof(zones_size));
735 memset(zholes_size, 0, sizeof(zholes_size));
737 for_each_online_node(nid) {
738 unsigned long start_pfn, end_pfn, pages_present;
740 get_region(nid, &start_pfn, &end_pfn, &pages_present);
742 zones_size[ZONE_DMA] = end_pfn - start_pfn;
743 zholes_size[ZONE_DMA] = zones_size[ZONE_DMA] - pages_present;
745 dbg("free_area_init node %d %lx %lx (hole: %lx)\n", nid,
746 zones_size[ZONE_DMA], start_pfn, zholes_size[ZONE_DMA]);
748 free_area_init_node(nid, NODE_DATA(nid), zones_size, start_pfn,
749 zholes_size);
753 static int __init early_numa(char *p)
755 if (!p)
756 return 0;
758 if (strstr(p, "off"))
759 numa_enabled = 0;
761 if (strstr(p, "debug"))
762 numa_debug = 1;
764 return 0;
766 early_param("numa", early_numa);
768 #ifdef CONFIG_MEMORY_HOTPLUG
770 * Find the node associated with a hot added memory section. Section
771 * corresponds to a SPARSEMEM section, not an LMB. It is assumed that
772 * sections are fully contained within a single LMB.
774 int hot_add_scn_to_nid(unsigned long scn_addr)
776 struct device_node *memory = NULL;
777 nodemask_t nodes;
778 int default_nid = any_online_node(NODE_MASK_ALL);
779 int nid;
781 if (!numa_enabled || (min_common_depth < 0))
782 return default_nid;
784 while ((memory = of_find_node_by_type(memory, "memory")) != NULL) {
785 unsigned long start, size;
786 int ranges;
787 const unsigned int *memcell_buf;
788 unsigned int len;
790 memcell_buf = get_property(memory, "reg", &len);
791 if (!memcell_buf || len <= 0)
792 continue;
794 /* ranges in cell */
795 ranges = (len >> 2) / (n_mem_addr_cells + n_mem_size_cells);
796 ha_new_range:
797 start = read_n_cells(n_mem_addr_cells, &memcell_buf);
798 size = read_n_cells(n_mem_size_cells, &memcell_buf);
799 nid = of_node_to_nid_single(memory);
801 /* Domains not present at boot default to 0 */
802 if (nid < 0 || !node_online(nid))
803 nid = default_nid;
805 if ((scn_addr >= start) && (scn_addr < (start + size))) {
806 of_node_put(memory);
807 goto got_nid;
810 if (--ranges) /* process all ranges in cell */
811 goto ha_new_range;
813 BUG(); /* section address should be found above */
814 return 0;
816 /* Temporary code to ensure that returned node is not empty */
817 got_nid:
818 nodes_setall(nodes);
819 while (NODE_DATA(nid)->node_spanned_pages == 0) {
820 node_clear(nid, nodes);
821 nid = any_online_node(nodes);
823 return nid;
825 #endif /* CONFIG_MEMORY_HOTPLUG */