mm, oom: reduce dependency on tasklist_lock
[linux/fpc-iii.git] / mm / bootmem.c
blobbcb63ac48cc5e0d20eb7d1359b8d6d79a7358ac0
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/bootmem.h>
15 #include <linux/export.h>
16 #include <linux/kmemleak.h>
17 #include <linux/range.h>
18 #include <linux/memblock.h>
20 #include <asm/bug.h>
21 #include <asm/io.h>
22 #include <asm/processor.h>
24 #include "internal.h"
26 #ifndef CONFIG_NEED_MULTIPLE_NODES
27 struct pglist_data __refdata contig_page_data = {
28 .bdata = &bootmem_node_data[0]
30 EXPORT_SYMBOL(contig_page_data);
31 #endif
33 unsigned long max_low_pfn;
34 unsigned long min_low_pfn;
35 unsigned long max_pfn;
37 bootmem_data_t bootmem_node_data[MAX_NUMNODES] __initdata;
39 static struct list_head bdata_list __initdata = LIST_HEAD_INIT(bdata_list);
41 static int bootmem_debug;
43 static int __init bootmem_debug_setup(char *buf)
45 bootmem_debug = 1;
46 return 0;
48 early_param("bootmem_debug", bootmem_debug_setup);
50 #define bdebug(fmt, args...) ({ \
51 if (unlikely(bootmem_debug)) \
52 printk(KERN_INFO \
53 "bootmem::%s " fmt, \
54 __func__, ## args); \
57 static unsigned long __init bootmap_bytes(unsigned long pages)
59 unsigned long bytes = DIV_ROUND_UP(pages, 8);
61 return ALIGN(bytes, sizeof(long));
64 /**
65 * bootmem_bootmap_pages - calculate bitmap size in pages
66 * @pages: number of pages the bitmap has to represent
68 unsigned long __init bootmem_bootmap_pages(unsigned long pages)
70 unsigned long bytes = bootmap_bytes(pages);
72 return PAGE_ALIGN(bytes) >> PAGE_SHIFT;
76 * link bdata in order
78 static void __init link_bootmem(bootmem_data_t *bdata)
80 bootmem_data_t *ent;
82 list_for_each_entry(ent, &bdata_list, list) {
83 if (bdata->node_min_pfn < ent->node_min_pfn) {
84 list_add_tail(&bdata->list, &ent->list);
85 return;
89 list_add_tail(&bdata->list, &bdata_list);
93 * Called once to set up the allocator itself.
95 static unsigned long __init init_bootmem_core(bootmem_data_t *bdata,
96 unsigned long mapstart, unsigned long start, unsigned long end)
98 unsigned long mapsize;
100 mminit_validate_memmodel_limits(&start, &end);
101 bdata->node_bootmem_map = phys_to_virt(PFN_PHYS(mapstart));
102 bdata->node_min_pfn = start;
103 bdata->node_low_pfn = end;
104 link_bootmem(bdata);
107 * Initially all pages are reserved - setup_arch() has to
108 * register free RAM areas explicitly.
110 mapsize = bootmap_bytes(end - start);
111 memset(bdata->node_bootmem_map, 0xff, mapsize);
113 bdebug("nid=%td start=%lx map=%lx end=%lx mapsize=%lx\n",
114 bdata - bootmem_node_data, start, mapstart, end, mapsize);
116 return mapsize;
120 * init_bootmem_node - register a node as boot memory
121 * @pgdat: node to register
122 * @freepfn: pfn where the bitmap for this node is to be placed
123 * @startpfn: first pfn on the node
124 * @endpfn: first pfn after the node
126 * Returns the number of bytes needed to hold the bitmap for this node.
128 unsigned long __init init_bootmem_node(pg_data_t *pgdat, unsigned long freepfn,
129 unsigned long startpfn, unsigned long endpfn)
131 return init_bootmem_core(pgdat->bdata, freepfn, startpfn, endpfn);
135 * init_bootmem - register boot memory
136 * @start: pfn where the bitmap is to be placed
137 * @pages: number of available physical pages
139 * Returns the number of bytes needed to hold the bitmap.
141 unsigned long __init init_bootmem(unsigned long start, unsigned long pages)
143 max_low_pfn = pages;
144 min_low_pfn = start;
145 return init_bootmem_core(NODE_DATA(0)->bdata, start, 0, pages);
149 * free_bootmem_late - free bootmem pages directly to page allocator
150 * @addr: starting address of the range
151 * @size: size of the range in bytes
153 * This is only useful when the bootmem allocator has already been torn
154 * down, but we are still initializing the system. Pages are given directly
155 * to the page allocator, no bootmem metadata is updated because it is gone.
157 void __init free_bootmem_late(unsigned long addr, unsigned long size)
159 unsigned long cursor, end;
161 kmemleak_free_part(__va(addr), size);
163 cursor = PFN_UP(addr);
164 end = PFN_DOWN(addr + size);
166 for (; cursor < end; cursor++) {
167 __free_pages_bootmem(pfn_to_page(cursor), 0);
168 totalram_pages++;
172 static unsigned long __init free_all_bootmem_core(bootmem_data_t *bdata)
174 struct page *page;
175 unsigned long start, end, pages, count = 0;
177 if (!bdata->node_bootmem_map)
178 return 0;
180 start = bdata->node_min_pfn;
181 end = bdata->node_low_pfn;
183 bdebug("nid=%td start=%lx end=%lx\n",
184 bdata - bootmem_node_data, start, end);
186 while (start < end) {
187 unsigned long *map, idx, vec;
189 map = bdata->node_bootmem_map;
190 idx = start - bdata->node_min_pfn;
191 vec = ~map[idx / BITS_PER_LONG];
193 * If we have a properly aligned and fully unreserved
194 * BITS_PER_LONG block of pages in front of us, free
195 * it in one go.
197 if (IS_ALIGNED(start, BITS_PER_LONG) && vec == ~0UL) {
198 int order = ilog2(BITS_PER_LONG);
200 __free_pages_bootmem(pfn_to_page(start), order);
201 count += BITS_PER_LONG;
202 start += BITS_PER_LONG;
203 } else {
204 unsigned long off = 0;
206 vec >>= start & (BITS_PER_LONG - 1);
207 while (vec) {
208 if (vec & 1) {
209 page = pfn_to_page(start + off);
210 __free_pages_bootmem(page, 0);
211 count++;
213 vec >>= 1;
214 off++;
216 start = ALIGN(start + 1, BITS_PER_LONG);
220 page = virt_to_page(bdata->node_bootmem_map);
221 pages = bdata->node_low_pfn - bdata->node_min_pfn;
222 pages = bootmem_bootmap_pages(pages);
223 count += pages;
224 while (pages--)
225 __free_pages_bootmem(page++, 0);
227 bdebug("nid=%td released=%lx\n", bdata - bootmem_node_data, count);
229 return count;
233 * free_all_bootmem_node - release a node's free pages to the buddy allocator
234 * @pgdat: node to be released
236 * Returns the number of pages actually released.
238 unsigned long __init free_all_bootmem_node(pg_data_t *pgdat)
240 register_page_bootmem_info_node(pgdat);
241 return free_all_bootmem_core(pgdat->bdata);
245 * free_all_bootmem - release free pages to the buddy allocator
247 * Returns the number of pages actually released.
249 unsigned long __init free_all_bootmem(void)
251 unsigned long total_pages = 0;
252 bootmem_data_t *bdata;
254 list_for_each_entry(bdata, &bdata_list, list)
255 total_pages += free_all_bootmem_core(bdata);
257 return total_pages;
260 static void __init __free(bootmem_data_t *bdata,
261 unsigned long sidx, unsigned long eidx)
263 unsigned long idx;
265 bdebug("nid=%td start=%lx end=%lx\n", bdata - bootmem_node_data,
266 sidx + bdata->node_min_pfn,
267 eidx + bdata->node_min_pfn);
269 if (bdata->hint_idx > sidx)
270 bdata->hint_idx = sidx;
272 for (idx = sidx; idx < eidx; idx++)
273 if (!test_and_clear_bit(idx, bdata->node_bootmem_map))
274 BUG();
277 static int __init __reserve(bootmem_data_t *bdata, unsigned long sidx,
278 unsigned long eidx, int flags)
280 unsigned long idx;
281 int exclusive = flags & BOOTMEM_EXCLUSIVE;
283 bdebug("nid=%td start=%lx end=%lx flags=%x\n",
284 bdata - bootmem_node_data,
285 sidx + bdata->node_min_pfn,
286 eidx + bdata->node_min_pfn,
287 flags);
289 for (idx = sidx; idx < eidx; idx++)
290 if (test_and_set_bit(idx, bdata->node_bootmem_map)) {
291 if (exclusive) {
292 __free(bdata, sidx, idx);
293 return -EBUSY;
295 bdebug("silent double reserve of PFN %lx\n",
296 idx + bdata->node_min_pfn);
298 return 0;
301 static int __init mark_bootmem_node(bootmem_data_t *bdata,
302 unsigned long start, unsigned long end,
303 int reserve, int flags)
305 unsigned long sidx, eidx;
307 bdebug("nid=%td start=%lx end=%lx reserve=%d flags=%x\n",
308 bdata - bootmem_node_data, start, end, reserve, flags);
310 BUG_ON(start < bdata->node_min_pfn);
311 BUG_ON(end > bdata->node_low_pfn);
313 sidx = start - bdata->node_min_pfn;
314 eidx = end - bdata->node_min_pfn;
316 if (reserve)
317 return __reserve(bdata, sidx, eidx, flags);
318 else
319 __free(bdata, sidx, eidx);
320 return 0;
323 static int __init mark_bootmem(unsigned long start, unsigned long end,
324 int reserve, int flags)
326 unsigned long pos;
327 bootmem_data_t *bdata;
329 pos = start;
330 list_for_each_entry(bdata, &bdata_list, list) {
331 int err;
332 unsigned long max;
334 if (pos < bdata->node_min_pfn ||
335 pos >= bdata->node_low_pfn) {
336 BUG_ON(pos != start);
337 continue;
340 max = min(bdata->node_low_pfn, end);
342 err = mark_bootmem_node(bdata, pos, max, reserve, flags);
343 if (reserve && err) {
344 mark_bootmem(start, pos, 0, 0);
345 return err;
348 if (max == end)
349 return 0;
350 pos = bdata->node_low_pfn;
352 BUG();
356 * free_bootmem_node - mark a page range as usable
357 * @pgdat: node the range resides on
358 * @physaddr: starting address of the range
359 * @size: size of the range in bytes
361 * Partial pages will be considered reserved and left as they are.
363 * The range must reside completely on the specified node.
365 void __init free_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
366 unsigned long size)
368 unsigned long start, end;
370 kmemleak_free_part(__va(physaddr), size);
372 start = PFN_UP(physaddr);
373 end = PFN_DOWN(physaddr + size);
375 mark_bootmem_node(pgdat->bdata, start, end, 0, 0);
379 * free_bootmem - mark a page range as usable
380 * @addr: starting address of the range
381 * @size: size of the range in bytes
383 * Partial pages will be considered reserved and left as they are.
385 * The range must be contiguous but may span node boundaries.
387 void __init free_bootmem(unsigned long addr, unsigned long size)
389 unsigned long start, end;
391 kmemleak_free_part(__va(addr), size);
393 start = PFN_UP(addr);
394 end = PFN_DOWN(addr + size);
396 mark_bootmem(start, end, 0, 0);
400 * reserve_bootmem_node - mark a page range as reserved
401 * @pgdat: node the range resides on
402 * @physaddr: starting address of the range
403 * @size: size of the range in bytes
404 * @flags: reservation flags (see linux/bootmem.h)
406 * Partial pages will be reserved.
408 * The range must reside completely on the specified node.
410 int __init reserve_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
411 unsigned long size, int flags)
413 unsigned long start, end;
415 start = PFN_DOWN(physaddr);
416 end = PFN_UP(physaddr + size);
418 return mark_bootmem_node(pgdat->bdata, start, end, 1, flags);
422 * reserve_bootmem - mark a page range as usable
423 * @addr: starting address of the range
424 * @size: size of the range in bytes
425 * @flags: reservation flags (see linux/bootmem.h)
427 * Partial pages will be reserved.
429 * The range must be contiguous but may span node boundaries.
431 int __init reserve_bootmem(unsigned long addr, unsigned long size,
432 int flags)
434 unsigned long start, end;
436 start = PFN_DOWN(addr);
437 end = PFN_UP(addr + size);
439 return mark_bootmem(start, end, 1, flags);
442 int __weak __init reserve_bootmem_generic(unsigned long phys, unsigned long len,
443 int flags)
445 return reserve_bootmem(phys, len, flags);
448 static unsigned long __init align_idx(struct bootmem_data *bdata,
449 unsigned long idx, unsigned long step)
451 unsigned long base = bdata->node_min_pfn;
454 * Align the index with respect to the node start so that the
455 * combination of both satisfies the requested alignment.
458 return ALIGN(base + idx, step) - base;
461 static unsigned long __init align_off(struct bootmem_data *bdata,
462 unsigned long off, unsigned long align)
464 unsigned long base = PFN_PHYS(bdata->node_min_pfn);
466 /* Same as align_idx for byte offsets */
468 return ALIGN(base + off, align) - base;
471 static void * __init alloc_bootmem_bdata(struct bootmem_data *bdata,
472 unsigned long size, unsigned long align,
473 unsigned long goal, unsigned long limit)
475 unsigned long fallback = 0;
476 unsigned long min, max, start, sidx, midx, step;
478 bdebug("nid=%td size=%lx [%lu pages] align=%lx goal=%lx limit=%lx\n",
479 bdata - bootmem_node_data, size, PAGE_ALIGN(size) >> PAGE_SHIFT,
480 align, goal, limit);
482 BUG_ON(!size);
483 BUG_ON(align & (align - 1));
484 BUG_ON(limit && goal + size > limit);
486 if (!bdata->node_bootmem_map)
487 return NULL;
489 min = bdata->node_min_pfn;
490 max = bdata->node_low_pfn;
492 goal >>= PAGE_SHIFT;
493 limit >>= PAGE_SHIFT;
495 if (limit && max > limit)
496 max = limit;
497 if (max <= min)
498 return NULL;
500 step = max(align >> PAGE_SHIFT, 1UL);
502 if (goal && min < goal && goal < max)
503 start = ALIGN(goal, step);
504 else
505 start = ALIGN(min, step);
507 sidx = start - bdata->node_min_pfn;
508 midx = max - bdata->node_min_pfn;
510 if (bdata->hint_idx > sidx) {
512 * Handle the valid case of sidx being zero and still
513 * catch the fallback below.
515 fallback = sidx + 1;
516 sidx = align_idx(bdata, bdata->hint_idx, step);
519 while (1) {
520 int merge;
521 void *region;
522 unsigned long eidx, i, start_off, end_off;
523 find_block:
524 sidx = find_next_zero_bit(bdata->node_bootmem_map, midx, sidx);
525 sidx = align_idx(bdata, sidx, step);
526 eidx = sidx + PFN_UP(size);
528 if (sidx >= midx || eidx > midx)
529 break;
531 for (i = sidx; i < eidx; i++)
532 if (test_bit(i, bdata->node_bootmem_map)) {
533 sidx = align_idx(bdata, i, step);
534 if (sidx == i)
535 sidx += step;
536 goto find_block;
539 if (bdata->last_end_off & (PAGE_SIZE - 1) &&
540 PFN_DOWN(bdata->last_end_off) + 1 == sidx)
541 start_off = align_off(bdata, bdata->last_end_off, align);
542 else
543 start_off = PFN_PHYS(sidx);
545 merge = PFN_DOWN(start_off) < sidx;
546 end_off = start_off + size;
548 bdata->last_end_off = end_off;
549 bdata->hint_idx = PFN_UP(end_off);
552 * Reserve the area now:
554 if (__reserve(bdata, PFN_DOWN(start_off) + merge,
555 PFN_UP(end_off), BOOTMEM_EXCLUSIVE))
556 BUG();
558 region = phys_to_virt(PFN_PHYS(bdata->node_min_pfn) +
559 start_off);
560 memset(region, 0, size);
562 * The min_count is set to 0 so that bootmem allocated blocks
563 * are never reported as leaks.
565 kmemleak_alloc(region, size, 0, 0);
566 return region;
569 if (fallback) {
570 sidx = align_idx(bdata, fallback - 1, step);
571 fallback = 0;
572 goto find_block;
575 return NULL;
578 static void * __init alloc_arch_preferred_bootmem(bootmem_data_t *bdata,
579 unsigned long size, unsigned long align,
580 unsigned long goal, unsigned long limit)
582 if (WARN_ON_ONCE(slab_is_available()))
583 return kzalloc(size, GFP_NOWAIT);
585 #ifdef CONFIG_HAVE_ARCH_BOOTMEM
587 bootmem_data_t *p_bdata;
589 p_bdata = bootmem_arch_preferred_node(bdata, size, align,
590 goal, limit);
591 if (p_bdata)
592 return alloc_bootmem_bdata(p_bdata, size, align,
593 goal, limit);
595 #endif
596 return NULL;
599 static void * __init alloc_bootmem_core(unsigned long size,
600 unsigned long align,
601 unsigned long goal,
602 unsigned long limit)
604 bootmem_data_t *bdata;
605 void *region;
607 region = alloc_arch_preferred_bootmem(NULL, size, align, goal, limit);
608 if (region)
609 return region;
611 list_for_each_entry(bdata, &bdata_list, list) {
612 if (goal && bdata->node_low_pfn <= PFN_DOWN(goal))
613 continue;
614 if (limit && bdata->node_min_pfn >= PFN_DOWN(limit))
615 break;
617 region = alloc_bootmem_bdata(bdata, size, align, goal, limit);
618 if (region)
619 return region;
622 return NULL;
625 static void * __init ___alloc_bootmem_nopanic(unsigned long size,
626 unsigned long align,
627 unsigned long goal,
628 unsigned long limit)
630 void *ptr;
632 restart:
633 ptr = alloc_bootmem_core(size, align, goal, limit);
634 if (ptr)
635 return ptr;
636 if (goal) {
637 goal = 0;
638 goto restart;
641 return NULL;
645 * __alloc_bootmem_nopanic - allocate boot memory without panicking
646 * @size: size of the request in bytes
647 * @align: alignment of the region
648 * @goal: preferred starting address of the region
650 * The goal is dropped if it can not be satisfied and the allocation will
651 * fall back to memory below @goal.
653 * Allocation may happen on any node in the system.
655 * Returns NULL on failure.
657 void * __init __alloc_bootmem_nopanic(unsigned long size, unsigned long align,
658 unsigned long goal)
660 unsigned long limit = 0;
662 return ___alloc_bootmem_nopanic(size, align, goal, limit);
665 static void * __init ___alloc_bootmem(unsigned long size, unsigned long align,
666 unsigned long goal, unsigned long limit)
668 void *mem = ___alloc_bootmem_nopanic(size, align, goal, limit);
670 if (mem)
671 return mem;
673 * Whoops, we cannot satisfy the allocation request.
675 printk(KERN_ALERT "bootmem alloc of %lu bytes failed!\n", size);
676 panic("Out of memory");
677 return NULL;
681 * __alloc_bootmem - allocate boot memory
682 * @size: size of the request in bytes
683 * @align: alignment of the region
684 * @goal: preferred starting address of the region
686 * The goal is dropped if it can not be satisfied and the allocation will
687 * fall back to memory below @goal.
689 * Allocation may happen on any node in the system.
691 * The function panics if the request can not be satisfied.
693 void * __init __alloc_bootmem(unsigned long size, unsigned long align,
694 unsigned long goal)
696 unsigned long limit = 0;
698 return ___alloc_bootmem(size, align, goal, limit);
701 void * __init ___alloc_bootmem_node_nopanic(pg_data_t *pgdat,
702 unsigned long size, unsigned long align,
703 unsigned long goal, unsigned long limit)
705 void *ptr;
707 again:
708 ptr = alloc_arch_preferred_bootmem(pgdat->bdata, size,
709 align, goal, limit);
710 if (ptr)
711 return ptr;
713 /* do not panic in alloc_bootmem_bdata() */
714 if (limit && goal + size > limit)
715 limit = 0;
717 ptr = alloc_bootmem_bdata(pgdat->bdata, size, align, goal, limit);
718 if (ptr)
719 return ptr;
721 ptr = alloc_bootmem_core(size, align, goal, limit);
722 if (ptr)
723 return ptr;
725 if (goal) {
726 goal = 0;
727 goto again;
730 return NULL;
733 void * __init __alloc_bootmem_node_nopanic(pg_data_t *pgdat, unsigned long size,
734 unsigned long align, unsigned long goal)
736 if (WARN_ON_ONCE(slab_is_available()))
737 return kzalloc_node(size, GFP_NOWAIT, pgdat->node_id);
739 return ___alloc_bootmem_node_nopanic(pgdat, size, align, goal, 0);
742 void * __init ___alloc_bootmem_node(pg_data_t *pgdat, unsigned long size,
743 unsigned long align, unsigned long goal,
744 unsigned long limit)
746 void *ptr;
748 ptr = ___alloc_bootmem_node_nopanic(pgdat, size, align, goal, 0);
749 if (ptr)
750 return ptr;
752 printk(KERN_ALERT "bootmem alloc of %lu bytes failed!\n", size);
753 panic("Out of memory");
754 return NULL;
758 * __alloc_bootmem_node - allocate boot memory from a specific node
759 * @pgdat: node to allocate from
760 * @size: size of the request in bytes
761 * @align: alignment of the region
762 * @goal: preferred starting address of the region
764 * The goal is dropped if it can not be satisfied and the allocation will
765 * fall back to memory below @goal.
767 * Allocation may fall back to any node in the system if the specified node
768 * can not hold the requested memory.
770 * The function panics if the request can not be satisfied.
772 void * __init __alloc_bootmem_node(pg_data_t *pgdat, unsigned long size,
773 unsigned long align, unsigned long goal)
775 if (WARN_ON_ONCE(slab_is_available()))
776 return kzalloc_node(size, GFP_NOWAIT, pgdat->node_id);
778 return ___alloc_bootmem_node(pgdat, size, align, goal, 0);
781 void * __init __alloc_bootmem_node_high(pg_data_t *pgdat, unsigned long size,
782 unsigned long align, unsigned long goal)
784 #ifdef MAX_DMA32_PFN
785 unsigned long end_pfn;
787 if (WARN_ON_ONCE(slab_is_available()))
788 return kzalloc_node(size, GFP_NOWAIT, pgdat->node_id);
790 /* update goal according ...MAX_DMA32_PFN */
791 end_pfn = pgdat->node_start_pfn + pgdat->node_spanned_pages;
793 if (end_pfn > MAX_DMA32_PFN + (128 >> (20 - PAGE_SHIFT)) &&
794 (goal >> PAGE_SHIFT) < MAX_DMA32_PFN) {
795 void *ptr;
796 unsigned long new_goal;
798 new_goal = MAX_DMA32_PFN << PAGE_SHIFT;
799 ptr = alloc_bootmem_bdata(pgdat->bdata, size, align,
800 new_goal, 0);
801 if (ptr)
802 return ptr;
804 #endif
806 return __alloc_bootmem_node(pgdat, size, align, goal);
810 #ifndef ARCH_LOW_ADDRESS_LIMIT
811 #define ARCH_LOW_ADDRESS_LIMIT 0xffffffffUL
812 #endif
815 * __alloc_bootmem_low - allocate low boot memory
816 * @size: size of the request in bytes
817 * @align: alignment of the region
818 * @goal: preferred starting address of the region
820 * The goal is dropped if it can not be satisfied and the allocation will
821 * fall back to memory below @goal.
823 * Allocation may happen on any node in the system.
825 * The function panics if the request can not be satisfied.
827 void * __init __alloc_bootmem_low(unsigned long size, unsigned long align,
828 unsigned long goal)
830 return ___alloc_bootmem(size, align, goal, ARCH_LOW_ADDRESS_LIMIT);
834 * __alloc_bootmem_low_node - allocate low boot memory from a specific node
835 * @pgdat: node to allocate from
836 * @size: size of the request in bytes
837 * @align: alignment of the region
838 * @goal: preferred starting address of the region
840 * The goal is dropped if it can not be satisfied and the allocation will
841 * fall back to memory below @goal.
843 * Allocation may fall back to any node in the system if the specified node
844 * can not hold the requested memory.
846 * The function panics if the request can not be satisfied.
848 void * __init __alloc_bootmem_low_node(pg_data_t *pgdat, unsigned long size,
849 unsigned long align, unsigned long goal)
851 if (WARN_ON_ONCE(slab_is_available()))
852 return kzalloc_node(size, GFP_NOWAIT, pgdat->node_id);
854 return ___alloc_bootmem_node(pgdat, size, align,
855 goal, ARCH_LOW_ADDRESS_LIMIT);