x86/xen: Fix xen head ELF annotations
[linux-2.6/btrfs-unstable.git] / mm / bootmem.c
blob9fedb27c6451418035fdf26300fbdf8d9c7fc6c9
1 /*
2 * bootmem - A boot-time physical memory allocator and configurator
4 * Copyright (C) 1999 Ingo Molnar
5 * 1999 Kanoj Sarcar, SGI
6 * 2008 Johannes Weiner
8 * Access to this subsystem has to be serialized externally (which is true
9 * for the boot process anyway).
11 #include <linux/init.h>
12 #include <linux/pfn.h>
13 #include <linux/slab.h>
14 #include <linux/export.h>
15 #include <linux/kmemleak.h>
16 #include <linux/range.h>
17 #include <linux/bug.h>
18 #include <linux/io.h>
19 #include <linux/bootmem.h>
21 #include "internal.h"
23 #ifndef CONFIG_NEED_MULTIPLE_NODES
24 struct pglist_data __refdata contig_page_data = {
25 .bdata = &bootmem_node_data[0]
27 EXPORT_SYMBOL(contig_page_data);
28 #endif
30 unsigned long max_low_pfn;
31 unsigned long min_low_pfn;
32 unsigned long max_pfn;
33 unsigned long long max_possible_pfn;
35 bootmem_data_t bootmem_node_data[MAX_NUMNODES] __initdata;
37 static struct list_head bdata_list __initdata = LIST_HEAD_INIT(bdata_list);
39 static int bootmem_debug;
41 static int __init bootmem_debug_setup(char *buf)
43 bootmem_debug = 1;
44 return 0;
46 early_param("bootmem_debug", bootmem_debug_setup);
48 #define bdebug(fmt, args...) ({ \
49 if (unlikely(bootmem_debug)) \
50 pr_info("bootmem::%s " fmt, \
51 __func__, ## args); \
54 static unsigned long __init bootmap_bytes(unsigned long pages)
56 unsigned long bytes = DIV_ROUND_UP(pages, BITS_PER_BYTE);
58 return ALIGN(bytes, sizeof(long));
61 /**
62 * bootmem_bootmap_pages - calculate bitmap size in pages
63 * @pages: number of pages the bitmap has to represent
65 unsigned long __init bootmem_bootmap_pages(unsigned long pages)
67 unsigned long bytes = bootmap_bytes(pages);
69 return PAGE_ALIGN(bytes) >> PAGE_SHIFT;
73 * link bdata in order
75 static void __init link_bootmem(bootmem_data_t *bdata)
77 bootmem_data_t *ent;
79 list_for_each_entry(ent, &bdata_list, list) {
80 if (bdata->node_min_pfn < ent->node_min_pfn) {
81 list_add_tail(&bdata->list, &ent->list);
82 return;
86 list_add_tail(&bdata->list, &bdata_list);
90 * Called once to set up the allocator itself.
92 static unsigned long __init init_bootmem_core(bootmem_data_t *bdata,
93 unsigned long mapstart, unsigned long start, unsigned long end)
95 unsigned long mapsize;
97 mminit_validate_memmodel_limits(&start, &end);
98 bdata->node_bootmem_map = phys_to_virt(PFN_PHYS(mapstart));
99 bdata->node_min_pfn = start;
100 bdata->node_low_pfn = end;
101 link_bootmem(bdata);
104 * Initially all pages are reserved - setup_arch() has to
105 * register free RAM areas explicitly.
107 mapsize = bootmap_bytes(end - start);
108 memset(bdata->node_bootmem_map, 0xff, mapsize);
110 bdebug("nid=%td start=%lx map=%lx end=%lx mapsize=%lx\n",
111 bdata - bootmem_node_data, start, mapstart, end, mapsize);
113 return mapsize;
117 * init_bootmem_node - register a node as boot memory
118 * @pgdat: node to register
119 * @freepfn: pfn where the bitmap for this node is to be placed
120 * @startpfn: first pfn on the node
121 * @endpfn: first pfn after the node
123 * Returns the number of bytes needed to hold the bitmap for this node.
125 unsigned long __init init_bootmem_node(pg_data_t *pgdat, unsigned long freepfn,
126 unsigned long startpfn, unsigned long endpfn)
128 return init_bootmem_core(pgdat->bdata, freepfn, startpfn, endpfn);
132 * init_bootmem - register boot memory
133 * @start: pfn where the bitmap is to be placed
134 * @pages: number of available physical pages
136 * Returns the number of bytes needed to hold the bitmap.
138 unsigned long __init init_bootmem(unsigned long start, unsigned long pages)
140 max_low_pfn = pages;
141 min_low_pfn = start;
142 return init_bootmem_core(NODE_DATA(0)->bdata, start, 0, pages);
146 * free_bootmem_late - free bootmem pages directly to page allocator
147 * @addr: starting physical address of the range
148 * @size: size of the range in bytes
150 * This is only useful when the bootmem allocator has already been torn
151 * down, but we are still initializing the system. Pages are given directly
152 * to the page allocator, no bootmem metadata is updated because it is gone.
154 void __init free_bootmem_late(unsigned long physaddr, unsigned long size)
156 unsigned long cursor, end;
158 kmemleak_free_part_phys(physaddr, size);
160 cursor = PFN_UP(physaddr);
161 end = PFN_DOWN(physaddr + size);
163 for (; cursor < end; cursor++) {
164 __free_pages_bootmem(pfn_to_page(cursor), cursor, 0);
165 totalram_pages++;
169 static unsigned long __init free_all_bootmem_core(bootmem_data_t *bdata)
171 struct page *page;
172 unsigned long *map, start, end, pages, cur, count = 0;
174 if (!bdata->node_bootmem_map)
175 return 0;
177 map = bdata->node_bootmem_map;
178 start = bdata->node_min_pfn;
179 end = bdata->node_low_pfn;
181 bdebug("nid=%td start=%lx end=%lx\n",
182 bdata - bootmem_node_data, start, end);
184 while (start < end) {
185 unsigned long idx, vec;
186 unsigned shift;
188 idx = start - bdata->node_min_pfn;
189 shift = idx & (BITS_PER_LONG - 1);
191 * vec holds at most BITS_PER_LONG map bits,
192 * bit 0 corresponds to start.
194 vec = ~map[idx / BITS_PER_LONG];
196 if (shift) {
197 vec >>= shift;
198 if (end - start >= BITS_PER_LONG)
199 vec |= ~map[idx / BITS_PER_LONG + 1] <<
200 (BITS_PER_LONG - shift);
203 * If we have a properly aligned and fully unreserved
204 * BITS_PER_LONG block of pages in front of us, free
205 * it in one go.
207 if (IS_ALIGNED(start, BITS_PER_LONG) && vec == ~0UL) {
208 int order = ilog2(BITS_PER_LONG);
210 __free_pages_bootmem(pfn_to_page(start), start, order);
211 count += BITS_PER_LONG;
212 start += BITS_PER_LONG;
213 } else {
214 cur = start;
216 start = ALIGN(start + 1, BITS_PER_LONG);
217 while (vec && cur != start) {
218 if (vec & 1) {
219 page = pfn_to_page(cur);
220 __free_pages_bootmem(page, cur, 0);
221 count++;
223 vec >>= 1;
224 ++cur;
229 cur = bdata->node_min_pfn;
230 page = virt_to_page(bdata->node_bootmem_map);
231 pages = bdata->node_low_pfn - bdata->node_min_pfn;
232 pages = bootmem_bootmap_pages(pages);
233 count += pages;
234 while (pages--)
235 __free_pages_bootmem(page++, cur++, 0);
236 bdata->node_bootmem_map = NULL;
238 bdebug("nid=%td released=%lx\n", bdata - bootmem_node_data, count);
240 return count;
243 static int reset_managed_pages_done __initdata;
245 void reset_node_managed_pages(pg_data_t *pgdat)
247 struct zone *z;
249 for (z = pgdat->node_zones; z < pgdat->node_zones + MAX_NR_ZONES; z++)
250 z->managed_pages = 0;
253 void __init reset_all_zones_managed_pages(void)
255 struct pglist_data *pgdat;
257 if (reset_managed_pages_done)
258 return;
260 for_each_online_pgdat(pgdat)
261 reset_node_managed_pages(pgdat);
263 reset_managed_pages_done = 1;
267 * free_all_bootmem - release free pages to the buddy allocator
269 * Returns the number of pages actually released.
271 unsigned long __init free_all_bootmem(void)
273 unsigned long total_pages = 0;
274 bootmem_data_t *bdata;
276 reset_all_zones_managed_pages();
278 list_for_each_entry(bdata, &bdata_list, list)
279 total_pages += free_all_bootmem_core(bdata);
281 totalram_pages += total_pages;
283 return total_pages;
286 static void __init __free(bootmem_data_t *bdata,
287 unsigned long sidx, unsigned long eidx)
289 unsigned long idx;
291 bdebug("nid=%td start=%lx end=%lx\n", bdata - bootmem_node_data,
292 sidx + bdata->node_min_pfn,
293 eidx + bdata->node_min_pfn);
295 if (WARN_ON(bdata->node_bootmem_map == NULL))
296 return;
298 if (bdata->hint_idx > sidx)
299 bdata->hint_idx = sidx;
301 for (idx = sidx; idx < eidx; idx++)
302 if (!test_and_clear_bit(idx, bdata->node_bootmem_map))
303 BUG();
306 static int __init __reserve(bootmem_data_t *bdata, unsigned long sidx,
307 unsigned long eidx, int flags)
309 unsigned long idx;
310 int exclusive = flags & BOOTMEM_EXCLUSIVE;
312 bdebug("nid=%td start=%lx end=%lx flags=%x\n",
313 bdata - bootmem_node_data,
314 sidx + bdata->node_min_pfn,
315 eidx + bdata->node_min_pfn,
316 flags);
318 if (WARN_ON(bdata->node_bootmem_map == NULL))
319 return 0;
321 for (idx = sidx; idx < eidx; idx++)
322 if (test_and_set_bit(idx, bdata->node_bootmem_map)) {
323 if (exclusive) {
324 __free(bdata, sidx, idx);
325 return -EBUSY;
327 bdebug("silent double reserve of PFN %lx\n",
328 idx + bdata->node_min_pfn);
330 return 0;
333 static int __init mark_bootmem_node(bootmem_data_t *bdata,
334 unsigned long start, unsigned long end,
335 int reserve, int flags)
337 unsigned long sidx, eidx;
339 bdebug("nid=%td start=%lx end=%lx reserve=%d flags=%x\n",
340 bdata - bootmem_node_data, start, end, reserve, flags);
342 BUG_ON(start < bdata->node_min_pfn);
343 BUG_ON(end > bdata->node_low_pfn);
345 sidx = start - bdata->node_min_pfn;
346 eidx = end - bdata->node_min_pfn;
348 if (reserve)
349 return __reserve(bdata, sidx, eidx, flags);
350 else
351 __free(bdata, sidx, eidx);
352 return 0;
355 static int __init mark_bootmem(unsigned long start, unsigned long end,
356 int reserve, int flags)
358 unsigned long pos;
359 bootmem_data_t *bdata;
361 pos = start;
362 list_for_each_entry(bdata, &bdata_list, list) {
363 int err;
364 unsigned long max;
366 if (pos < bdata->node_min_pfn ||
367 pos >= bdata->node_low_pfn) {
368 BUG_ON(pos != start);
369 continue;
372 max = min(bdata->node_low_pfn, end);
374 err = mark_bootmem_node(bdata, pos, max, reserve, flags);
375 if (reserve && err) {
376 mark_bootmem(start, pos, 0, 0);
377 return err;
380 if (max == end)
381 return 0;
382 pos = bdata->node_low_pfn;
384 BUG();
388 * free_bootmem_node - mark a page range as usable
389 * @pgdat: node the range resides on
390 * @physaddr: starting address of the range
391 * @size: size of the range in bytes
393 * Partial pages will be considered reserved and left as they are.
395 * The range must reside completely on the specified node.
397 void __init free_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
398 unsigned long size)
400 unsigned long start, end;
402 kmemleak_free_part_phys(physaddr, size);
404 start = PFN_UP(physaddr);
405 end = PFN_DOWN(physaddr + size);
407 mark_bootmem_node(pgdat->bdata, start, end, 0, 0);
411 * free_bootmem - mark a page range as usable
412 * @addr: starting physical address of the range
413 * @size: size of the range in bytes
415 * Partial pages will be considered reserved and left as they are.
417 * The range must be contiguous but may span node boundaries.
419 void __init free_bootmem(unsigned long physaddr, unsigned long size)
421 unsigned long start, end;
423 kmemleak_free_part_phys(physaddr, size);
425 start = PFN_UP(physaddr);
426 end = PFN_DOWN(physaddr + size);
428 mark_bootmem(start, end, 0, 0);
432 * reserve_bootmem_node - mark a page range as reserved
433 * @pgdat: node the range resides on
434 * @physaddr: starting address of the range
435 * @size: size of the range in bytes
436 * @flags: reservation flags (see linux/bootmem.h)
438 * Partial pages will be reserved.
440 * The range must reside completely on the specified node.
442 int __init reserve_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
443 unsigned long size, int flags)
445 unsigned long start, end;
447 start = PFN_DOWN(physaddr);
448 end = PFN_UP(physaddr + size);
450 return mark_bootmem_node(pgdat->bdata, start, end, 1, flags);
454 * reserve_bootmem - mark a page range as reserved
455 * @addr: starting address of the range
456 * @size: size of the range in bytes
457 * @flags: reservation flags (see linux/bootmem.h)
459 * Partial pages will be reserved.
461 * The range must be contiguous but may span node boundaries.
463 int __init reserve_bootmem(unsigned long addr, unsigned long size,
464 int flags)
466 unsigned long start, end;
468 start = PFN_DOWN(addr);
469 end = PFN_UP(addr + size);
471 return mark_bootmem(start, end, 1, flags);
474 static unsigned long __init align_idx(struct bootmem_data *bdata,
475 unsigned long idx, unsigned long step)
477 unsigned long base = bdata->node_min_pfn;
480 * Align the index with respect to the node start so that the
481 * combination of both satisfies the requested alignment.
484 return ALIGN(base + idx, step) - base;
487 static unsigned long __init align_off(struct bootmem_data *bdata,
488 unsigned long off, unsigned long align)
490 unsigned long base = PFN_PHYS(bdata->node_min_pfn);
492 /* Same as align_idx for byte offsets */
494 return ALIGN(base + off, align) - base;
497 static void * __init alloc_bootmem_bdata(struct bootmem_data *bdata,
498 unsigned long size, unsigned long align,
499 unsigned long goal, unsigned long limit)
501 unsigned long fallback = 0;
502 unsigned long min, max, start, sidx, midx, step;
504 bdebug("nid=%td size=%lx [%lu pages] align=%lx goal=%lx limit=%lx\n",
505 bdata - bootmem_node_data, size, PAGE_ALIGN(size) >> PAGE_SHIFT,
506 align, goal, limit);
508 BUG_ON(!size);
509 BUG_ON(align & (align - 1));
510 BUG_ON(limit && goal + size > limit);
512 if (!bdata->node_bootmem_map)
513 return NULL;
515 min = bdata->node_min_pfn;
516 max = bdata->node_low_pfn;
518 goal >>= PAGE_SHIFT;
519 limit >>= PAGE_SHIFT;
521 if (limit && max > limit)
522 max = limit;
523 if (max <= min)
524 return NULL;
526 step = max(align >> PAGE_SHIFT, 1UL);
528 if (goal && min < goal && goal < max)
529 start = ALIGN(goal, step);
530 else
531 start = ALIGN(min, step);
533 sidx = start - bdata->node_min_pfn;
534 midx = max - bdata->node_min_pfn;
536 if (bdata->hint_idx > sidx) {
538 * Handle the valid case of sidx being zero and still
539 * catch the fallback below.
541 fallback = sidx + 1;
542 sidx = align_idx(bdata, bdata->hint_idx, step);
545 while (1) {
546 int merge;
547 void *region;
548 unsigned long eidx, i, start_off, end_off;
549 find_block:
550 sidx = find_next_zero_bit(bdata->node_bootmem_map, midx, sidx);
551 sidx = align_idx(bdata, sidx, step);
552 eidx = sidx + PFN_UP(size);
554 if (sidx >= midx || eidx > midx)
555 break;
557 for (i = sidx; i < eidx; i++)
558 if (test_bit(i, bdata->node_bootmem_map)) {
559 sidx = align_idx(bdata, i, step);
560 if (sidx == i)
561 sidx += step;
562 goto find_block;
565 if (bdata->last_end_off & (PAGE_SIZE - 1) &&
566 PFN_DOWN(bdata->last_end_off) + 1 == sidx)
567 start_off = align_off(bdata, bdata->last_end_off, align);
568 else
569 start_off = PFN_PHYS(sidx);
571 merge = PFN_DOWN(start_off) < sidx;
572 end_off = start_off + size;
574 bdata->last_end_off = end_off;
575 bdata->hint_idx = PFN_UP(end_off);
578 * Reserve the area now:
580 if (__reserve(bdata, PFN_DOWN(start_off) + merge,
581 PFN_UP(end_off), BOOTMEM_EXCLUSIVE))
582 BUG();
584 region = phys_to_virt(PFN_PHYS(bdata->node_min_pfn) +
585 start_off);
586 memset(region, 0, size);
588 * The min_count is set to 0 so that bootmem allocated blocks
589 * are never reported as leaks.
591 kmemleak_alloc(region, size, 0, 0);
592 return region;
595 if (fallback) {
596 sidx = align_idx(bdata, fallback - 1, step);
597 fallback = 0;
598 goto find_block;
601 return NULL;
604 static void * __init alloc_bootmem_core(unsigned long size,
605 unsigned long align,
606 unsigned long goal,
607 unsigned long limit)
609 bootmem_data_t *bdata;
610 void *region;
612 if (WARN_ON_ONCE(slab_is_available()))
613 return kzalloc(size, GFP_NOWAIT);
615 list_for_each_entry(bdata, &bdata_list, list) {
616 if (goal && bdata->node_low_pfn <= PFN_DOWN(goal))
617 continue;
618 if (limit && bdata->node_min_pfn >= PFN_DOWN(limit))
619 break;
621 region = alloc_bootmem_bdata(bdata, size, align, goal, limit);
622 if (region)
623 return region;
626 return NULL;
629 static void * __init ___alloc_bootmem_nopanic(unsigned long size,
630 unsigned long align,
631 unsigned long goal,
632 unsigned long limit)
634 void *ptr;
636 restart:
637 ptr = alloc_bootmem_core(size, align, goal, limit);
638 if (ptr)
639 return ptr;
640 if (goal) {
641 goal = 0;
642 goto restart;
645 return NULL;
649 * __alloc_bootmem_nopanic - allocate boot memory without panicking
650 * @size: size of the request in bytes
651 * @align: alignment of the region
652 * @goal: preferred starting address of the region
654 * The goal is dropped if it can not be satisfied and the allocation will
655 * fall back to memory below @goal.
657 * Allocation may happen on any node in the system.
659 * Returns NULL on failure.
661 void * __init __alloc_bootmem_nopanic(unsigned long size, unsigned long align,
662 unsigned long goal)
664 unsigned long limit = 0;
666 return ___alloc_bootmem_nopanic(size, align, goal, limit);
669 static void * __init ___alloc_bootmem(unsigned long size, unsigned long align,
670 unsigned long goal, unsigned long limit)
672 void *mem = ___alloc_bootmem_nopanic(size, align, goal, limit);
674 if (mem)
675 return mem;
677 * Whoops, we cannot satisfy the allocation request.
679 pr_alert("bootmem alloc of %lu bytes failed!\n", size);
680 panic("Out of memory");
681 return NULL;
685 * __alloc_bootmem - allocate boot memory
686 * @size: size of the request in bytes
687 * @align: alignment of the region
688 * @goal: preferred starting address of the region
690 * The goal is dropped if it can not be satisfied and the allocation will
691 * fall back to memory below @goal.
693 * Allocation may happen on any node in the system.
695 * The function panics if the request can not be satisfied.
697 void * __init __alloc_bootmem(unsigned long size, unsigned long align,
698 unsigned long goal)
700 unsigned long limit = 0;
702 return ___alloc_bootmem(size, align, goal, limit);
705 void * __init ___alloc_bootmem_node_nopanic(pg_data_t *pgdat,
706 unsigned long size, unsigned long align,
707 unsigned long goal, unsigned long limit)
709 void *ptr;
711 if (WARN_ON_ONCE(slab_is_available()))
712 return kzalloc_node(size, GFP_NOWAIT, pgdat->node_id);
713 again:
715 /* do not panic in alloc_bootmem_bdata() */
716 if (limit && goal + size > limit)
717 limit = 0;
719 ptr = alloc_bootmem_bdata(pgdat->bdata, size, align, goal, limit);
720 if (ptr)
721 return ptr;
723 ptr = alloc_bootmem_core(size, align, goal, limit);
724 if (ptr)
725 return ptr;
727 if (goal) {
728 goal = 0;
729 goto again;
732 return NULL;
735 void * __init __alloc_bootmem_node_nopanic(pg_data_t *pgdat, unsigned long size,
736 unsigned long align, unsigned long goal)
738 return ___alloc_bootmem_node_nopanic(pgdat, size, align, goal, 0);
741 void * __init ___alloc_bootmem_node(pg_data_t *pgdat, unsigned long size,
742 unsigned long align, unsigned long goal,
743 unsigned long limit)
745 void *ptr;
747 ptr = ___alloc_bootmem_node_nopanic(pgdat, size, align, goal, 0);
748 if (ptr)
749 return ptr;
751 pr_alert("bootmem alloc of %lu bytes failed!\n", size);
752 panic("Out of memory");
753 return NULL;
757 * __alloc_bootmem_node - allocate boot memory from a specific node
758 * @pgdat: node to allocate from
759 * @size: size of the request in bytes
760 * @align: alignment of the region
761 * @goal: preferred starting address of the region
763 * The goal is dropped if it can not be satisfied and the allocation will
764 * fall back to memory below @goal.
766 * Allocation may fall back to any node in the system if the specified node
767 * can not hold the requested memory.
769 * The function panics if the request can not be satisfied.
771 void * __init __alloc_bootmem_node(pg_data_t *pgdat, unsigned long size,
772 unsigned long align, unsigned long goal)
774 if (WARN_ON_ONCE(slab_is_available()))
775 return kzalloc_node(size, GFP_NOWAIT, pgdat->node_id);
777 return ___alloc_bootmem_node(pgdat, size, align, goal, 0);
780 void * __init __alloc_bootmem_node_high(pg_data_t *pgdat, unsigned long size,
781 unsigned long align, unsigned long goal)
783 #ifdef MAX_DMA32_PFN
784 unsigned long end_pfn;
786 if (WARN_ON_ONCE(slab_is_available()))
787 return kzalloc_node(size, GFP_NOWAIT, pgdat->node_id);
789 /* update goal according ...MAX_DMA32_PFN */
790 end_pfn = pgdat_end_pfn(pgdat);
792 if (end_pfn > MAX_DMA32_PFN + (128 >> (20 - PAGE_SHIFT)) &&
793 (goal >> PAGE_SHIFT) < MAX_DMA32_PFN) {
794 void *ptr;
795 unsigned long new_goal;
797 new_goal = MAX_DMA32_PFN << PAGE_SHIFT;
798 ptr = alloc_bootmem_bdata(pgdat->bdata, size, align,
799 new_goal, 0);
800 if (ptr)
801 return ptr;
803 #endif
805 return __alloc_bootmem_node(pgdat, size, align, goal);
810 * __alloc_bootmem_low - allocate low boot memory
811 * @size: size of the request in bytes
812 * @align: alignment of the region
813 * @goal: preferred starting address of the region
815 * The goal is dropped if it can not be satisfied and the allocation will
816 * fall back to memory below @goal.
818 * Allocation may happen on any node in the system.
820 * The function panics if the request can not be satisfied.
822 void * __init __alloc_bootmem_low(unsigned long size, unsigned long align,
823 unsigned long goal)
825 return ___alloc_bootmem(size, align, goal, ARCH_LOW_ADDRESS_LIMIT);
828 void * __init __alloc_bootmem_low_nopanic(unsigned long size,
829 unsigned long align,
830 unsigned long goal)
832 return ___alloc_bootmem_nopanic(size, align, goal,
833 ARCH_LOW_ADDRESS_LIMIT);
837 * __alloc_bootmem_low_node - allocate low boot memory from a specific node
838 * @pgdat: node to allocate from
839 * @size: size of the request in bytes
840 * @align: alignment of the region
841 * @goal: preferred starting address of the region
843 * The goal is dropped if it can not be satisfied and the allocation will
844 * fall back to memory below @goal.
846 * Allocation may fall back to any node in the system if the specified node
847 * can not hold the requested memory.
849 * The function panics if the request can not be satisfied.
851 void * __init __alloc_bootmem_low_node(pg_data_t *pgdat, unsigned long size,
852 unsigned long align, unsigned long goal)
854 if (WARN_ON_ONCE(slab_is_available()))
855 return kzalloc_node(size, GFP_NOWAIT, pgdat->node_id);
857 return ___alloc_bootmem_node(pgdat, size, align,
858 goal, ARCH_LOW_ADDRESS_LIMIT);