Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next
[linux-2.6.git] / mm / bootmem.c
blob6ab7744e692ed86cd4417041686dc3a0821cab9f
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 physical 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 physaddr, unsigned long size)
159 unsigned long cursor, end;
161 kmemleak_free_part(__va(physaddr), size);
163 cursor = PFN_UP(physaddr);
164 end = PFN_DOWN(physaddr + 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;
188 unsigned shift;
190 map = bdata->node_bootmem_map;
191 idx = start - bdata->node_min_pfn;
192 shift = idx & (BITS_PER_LONG - 1);
194 * vec holds at most BITS_PER_LONG map bits,
195 * bit 0 corresponds to start.
197 vec = ~map[idx / BITS_PER_LONG];
199 if (shift) {
200 vec >>= shift;
201 if (end - start >= BITS_PER_LONG)
202 vec |= ~map[idx / BITS_PER_LONG + 1] <<
203 (BITS_PER_LONG - shift);
206 * If we have a properly aligned and fully unreserved
207 * BITS_PER_LONG block of pages in front of us, free
208 * it in one go.
210 if (IS_ALIGNED(start, BITS_PER_LONG) && vec == ~0UL) {
211 int order = ilog2(BITS_PER_LONG);
213 __free_pages_bootmem(pfn_to_page(start), order);
214 count += BITS_PER_LONG;
215 start += BITS_PER_LONG;
216 } else {
217 unsigned long cur = start;
219 start = ALIGN(start + 1, BITS_PER_LONG);
220 while (vec && cur != start) {
221 if (vec & 1) {
222 page = pfn_to_page(cur);
223 __free_pages_bootmem(page, 0);
224 count++;
226 vec >>= 1;
227 ++cur;
232 page = virt_to_page(bdata->node_bootmem_map);
233 pages = bdata->node_low_pfn - bdata->node_min_pfn;
234 pages = bootmem_bootmap_pages(pages);
235 count += pages;
236 while (pages--)
237 __free_pages_bootmem(page++, 0);
239 bdebug("nid=%td released=%lx\n", bdata - bootmem_node_data, count);
241 return count;
244 static int reset_managed_pages_done __initdata;
246 static inline void __init reset_node_managed_pages(pg_data_t *pgdat)
248 struct zone *z;
250 if (reset_managed_pages_done)
251 return;
253 for (z = pgdat->node_zones; z < pgdat->node_zones + MAX_NR_ZONES; z++)
254 z->managed_pages = 0;
257 void __init reset_all_zones_managed_pages(void)
259 struct pglist_data *pgdat;
261 for_each_online_pgdat(pgdat)
262 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 (bdata->hint_idx > sidx)
296 bdata->hint_idx = sidx;
298 for (idx = sidx; idx < eidx; idx++)
299 if (!test_and_clear_bit(idx, bdata->node_bootmem_map))
300 BUG();
303 static int __init __reserve(bootmem_data_t *bdata, unsigned long sidx,
304 unsigned long eidx, int flags)
306 unsigned long idx;
307 int exclusive = flags & BOOTMEM_EXCLUSIVE;
309 bdebug("nid=%td start=%lx end=%lx flags=%x\n",
310 bdata - bootmem_node_data,
311 sidx + bdata->node_min_pfn,
312 eidx + bdata->node_min_pfn,
313 flags);
315 for (idx = sidx; idx < eidx; idx++)
316 if (test_and_set_bit(idx, bdata->node_bootmem_map)) {
317 if (exclusive) {
318 __free(bdata, sidx, idx);
319 return -EBUSY;
321 bdebug("silent double reserve of PFN %lx\n",
322 idx + bdata->node_min_pfn);
324 return 0;
327 static int __init mark_bootmem_node(bootmem_data_t *bdata,
328 unsigned long start, unsigned long end,
329 int reserve, int flags)
331 unsigned long sidx, eidx;
333 bdebug("nid=%td start=%lx end=%lx reserve=%d flags=%x\n",
334 bdata - bootmem_node_data, start, end, reserve, flags);
336 BUG_ON(start < bdata->node_min_pfn);
337 BUG_ON(end > bdata->node_low_pfn);
339 sidx = start - bdata->node_min_pfn;
340 eidx = end - bdata->node_min_pfn;
342 if (reserve)
343 return __reserve(bdata, sidx, eidx, flags);
344 else
345 __free(bdata, sidx, eidx);
346 return 0;
349 static int __init mark_bootmem(unsigned long start, unsigned long end,
350 int reserve, int flags)
352 unsigned long pos;
353 bootmem_data_t *bdata;
355 pos = start;
356 list_for_each_entry(bdata, &bdata_list, list) {
357 int err;
358 unsigned long max;
360 if (pos < bdata->node_min_pfn ||
361 pos >= bdata->node_low_pfn) {
362 BUG_ON(pos != start);
363 continue;
366 max = min(bdata->node_low_pfn, end);
368 err = mark_bootmem_node(bdata, pos, max, reserve, flags);
369 if (reserve && err) {
370 mark_bootmem(start, pos, 0, 0);
371 return err;
374 if (max == end)
375 return 0;
376 pos = bdata->node_low_pfn;
378 BUG();
382 * free_bootmem_node - mark a page range as usable
383 * @pgdat: node the range resides on
384 * @physaddr: starting address of the range
385 * @size: size of the range in bytes
387 * Partial pages will be considered reserved and left as they are.
389 * The range must reside completely on the specified node.
391 void __init free_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
392 unsigned long size)
394 unsigned long start, end;
396 kmemleak_free_part(__va(physaddr), size);
398 start = PFN_UP(physaddr);
399 end = PFN_DOWN(physaddr + size);
401 mark_bootmem_node(pgdat->bdata, start, end, 0, 0);
405 * free_bootmem - mark a page range as usable
406 * @addr: starting physical address of the range
407 * @size: size of the range in bytes
409 * Partial pages will be considered reserved and left as they are.
411 * The range must be contiguous but may span node boundaries.
413 void __init free_bootmem(unsigned long physaddr, unsigned long size)
415 unsigned long start, end;
417 kmemleak_free_part(__va(physaddr), size);
419 start = PFN_UP(physaddr);
420 end = PFN_DOWN(physaddr + size);
422 mark_bootmem(start, end, 0, 0);
426 * reserve_bootmem_node - mark a page range as reserved
427 * @pgdat: node the range resides on
428 * @physaddr: starting address of the range
429 * @size: size of the range in bytes
430 * @flags: reservation flags (see linux/bootmem.h)
432 * Partial pages will be reserved.
434 * The range must reside completely on the specified node.
436 int __init reserve_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
437 unsigned long size, int flags)
439 unsigned long start, end;
441 start = PFN_DOWN(physaddr);
442 end = PFN_UP(physaddr + size);
444 return mark_bootmem_node(pgdat->bdata, start, end, 1, flags);
448 * reserve_bootmem - mark a page range as reserved
449 * @addr: starting address of the range
450 * @size: size of the range in bytes
451 * @flags: reservation flags (see linux/bootmem.h)
453 * Partial pages will be reserved.
455 * The range must be contiguous but may span node boundaries.
457 int __init reserve_bootmem(unsigned long addr, unsigned long size,
458 int flags)
460 unsigned long start, end;
462 start = PFN_DOWN(addr);
463 end = PFN_UP(addr + size);
465 return mark_bootmem(start, end, 1, flags);
468 static unsigned long __init align_idx(struct bootmem_data *bdata,
469 unsigned long idx, unsigned long step)
471 unsigned long base = bdata->node_min_pfn;
474 * Align the index with respect to the node start so that the
475 * combination of both satisfies the requested alignment.
478 return ALIGN(base + idx, step) - base;
481 static unsigned long __init align_off(struct bootmem_data *bdata,
482 unsigned long off, unsigned long align)
484 unsigned long base = PFN_PHYS(bdata->node_min_pfn);
486 /* Same as align_idx for byte offsets */
488 return ALIGN(base + off, align) - base;
491 static void * __init alloc_bootmem_bdata(struct bootmem_data *bdata,
492 unsigned long size, unsigned long align,
493 unsigned long goal, unsigned long limit)
495 unsigned long fallback = 0;
496 unsigned long min, max, start, sidx, midx, step;
498 bdebug("nid=%td size=%lx [%lu pages] align=%lx goal=%lx limit=%lx\n",
499 bdata - bootmem_node_data, size, PAGE_ALIGN(size) >> PAGE_SHIFT,
500 align, goal, limit);
502 BUG_ON(!size);
503 BUG_ON(align & (align - 1));
504 BUG_ON(limit && goal + size > limit);
506 if (!bdata->node_bootmem_map)
507 return NULL;
509 min = bdata->node_min_pfn;
510 max = bdata->node_low_pfn;
512 goal >>= PAGE_SHIFT;
513 limit >>= PAGE_SHIFT;
515 if (limit && max > limit)
516 max = limit;
517 if (max <= min)
518 return NULL;
520 step = max(align >> PAGE_SHIFT, 1UL);
522 if (goal && min < goal && goal < max)
523 start = ALIGN(goal, step);
524 else
525 start = ALIGN(min, step);
527 sidx = start - bdata->node_min_pfn;
528 midx = max - bdata->node_min_pfn;
530 if (bdata->hint_idx > sidx) {
532 * Handle the valid case of sidx being zero and still
533 * catch the fallback below.
535 fallback = sidx + 1;
536 sidx = align_idx(bdata, bdata->hint_idx, step);
539 while (1) {
540 int merge;
541 void *region;
542 unsigned long eidx, i, start_off, end_off;
543 find_block:
544 sidx = find_next_zero_bit(bdata->node_bootmem_map, midx, sidx);
545 sidx = align_idx(bdata, sidx, step);
546 eidx = sidx + PFN_UP(size);
548 if (sidx >= midx || eidx > midx)
549 break;
551 for (i = sidx; i < eidx; i++)
552 if (test_bit(i, bdata->node_bootmem_map)) {
553 sidx = align_idx(bdata, i, step);
554 if (sidx == i)
555 sidx += step;
556 goto find_block;
559 if (bdata->last_end_off & (PAGE_SIZE - 1) &&
560 PFN_DOWN(bdata->last_end_off) + 1 == sidx)
561 start_off = align_off(bdata, bdata->last_end_off, align);
562 else
563 start_off = PFN_PHYS(sidx);
565 merge = PFN_DOWN(start_off) < sidx;
566 end_off = start_off + size;
568 bdata->last_end_off = end_off;
569 bdata->hint_idx = PFN_UP(end_off);
572 * Reserve the area now:
574 if (__reserve(bdata, PFN_DOWN(start_off) + merge,
575 PFN_UP(end_off), BOOTMEM_EXCLUSIVE))
576 BUG();
578 region = phys_to_virt(PFN_PHYS(bdata->node_min_pfn) +
579 start_off);
580 memset(region, 0, size);
582 * The min_count is set to 0 so that bootmem allocated blocks
583 * are never reported as leaks.
585 kmemleak_alloc(region, size, 0, 0);
586 return region;
589 if (fallback) {
590 sidx = align_idx(bdata, fallback - 1, step);
591 fallback = 0;
592 goto find_block;
595 return NULL;
598 static void * __init alloc_bootmem_core(unsigned long size,
599 unsigned long align,
600 unsigned long goal,
601 unsigned long limit)
603 bootmem_data_t *bdata;
604 void *region;
606 if (WARN_ON_ONCE(slab_is_available()))
607 return kzalloc(size, GFP_NOWAIT);
609 list_for_each_entry(bdata, &bdata_list, list) {
610 if (goal && bdata->node_low_pfn <= PFN_DOWN(goal))
611 continue;
612 if (limit && bdata->node_min_pfn >= PFN_DOWN(limit))
613 break;
615 region = alloc_bootmem_bdata(bdata, size, align, goal, limit);
616 if (region)
617 return region;
620 return NULL;
623 static void * __init ___alloc_bootmem_nopanic(unsigned long size,
624 unsigned long align,
625 unsigned long goal,
626 unsigned long limit)
628 void *ptr;
630 restart:
631 ptr = alloc_bootmem_core(size, align, goal, limit);
632 if (ptr)
633 return ptr;
634 if (goal) {
635 goal = 0;
636 goto restart;
639 return NULL;
643 * __alloc_bootmem_nopanic - allocate boot memory without panicking
644 * @size: size of the request in bytes
645 * @align: alignment of the region
646 * @goal: preferred starting address of the region
648 * The goal is dropped if it can not be satisfied and the allocation will
649 * fall back to memory below @goal.
651 * Allocation may happen on any node in the system.
653 * Returns NULL on failure.
655 void * __init __alloc_bootmem_nopanic(unsigned long size, unsigned long align,
656 unsigned long goal)
658 unsigned long limit = 0;
660 return ___alloc_bootmem_nopanic(size, align, goal, limit);
663 static void * __init ___alloc_bootmem(unsigned long size, unsigned long align,
664 unsigned long goal, unsigned long limit)
666 void *mem = ___alloc_bootmem_nopanic(size, align, goal, limit);
668 if (mem)
669 return mem;
671 * Whoops, we cannot satisfy the allocation request.
673 printk(KERN_ALERT "bootmem alloc of %lu bytes failed!\n", size);
674 panic("Out of memory");
675 return NULL;
679 * __alloc_bootmem - allocate boot memory
680 * @size: size of the request in bytes
681 * @align: alignment of the region
682 * @goal: preferred starting address of the region
684 * The goal is dropped if it can not be satisfied and the allocation will
685 * fall back to memory below @goal.
687 * Allocation may happen on any node in the system.
689 * The function panics if the request can not be satisfied.
691 void * __init __alloc_bootmem(unsigned long size, unsigned long align,
692 unsigned long goal)
694 unsigned long limit = 0;
696 return ___alloc_bootmem(size, align, goal, limit);
699 void * __init ___alloc_bootmem_node_nopanic(pg_data_t *pgdat,
700 unsigned long size, unsigned long align,
701 unsigned long goal, unsigned long limit)
703 void *ptr;
705 if (WARN_ON_ONCE(slab_is_available()))
706 return kzalloc(size, GFP_NOWAIT);
707 again:
709 /* do not panic in alloc_bootmem_bdata() */
710 if (limit && goal + size > limit)
711 limit = 0;
713 ptr = alloc_bootmem_bdata(pgdat->bdata, size, align, goal, limit);
714 if (ptr)
715 return ptr;
717 ptr = alloc_bootmem_core(size, align, goal, limit);
718 if (ptr)
719 return ptr;
721 if (goal) {
722 goal = 0;
723 goto again;
726 return NULL;
729 void * __init __alloc_bootmem_node_nopanic(pg_data_t *pgdat, unsigned long size,
730 unsigned long align, unsigned long goal)
732 if (WARN_ON_ONCE(slab_is_available()))
733 return kzalloc_node(size, GFP_NOWAIT, pgdat->node_id);
735 return ___alloc_bootmem_node_nopanic(pgdat, size, align, goal, 0);
738 void * __init ___alloc_bootmem_node(pg_data_t *pgdat, unsigned long size,
739 unsigned long align, unsigned long goal,
740 unsigned long limit)
742 void *ptr;
744 ptr = ___alloc_bootmem_node_nopanic(pgdat, size, align, goal, 0);
745 if (ptr)
746 return ptr;
748 printk(KERN_ALERT "bootmem alloc of %lu bytes failed!\n", size);
749 panic("Out of memory");
750 return NULL;
754 * __alloc_bootmem_node - allocate boot memory from a specific node
755 * @pgdat: node to allocate from
756 * @size: size of the request in bytes
757 * @align: alignment of the region
758 * @goal: preferred starting address of the region
760 * The goal is dropped if it can not be satisfied and the allocation will
761 * fall back to memory below @goal.
763 * Allocation may fall back to any node in the system if the specified node
764 * can not hold the requested memory.
766 * The function panics if the request can not be satisfied.
768 void * __init __alloc_bootmem_node(pg_data_t *pgdat, unsigned long size,
769 unsigned long align, unsigned long goal)
771 if (WARN_ON_ONCE(slab_is_available()))
772 return kzalloc_node(size, GFP_NOWAIT, pgdat->node_id);
774 return ___alloc_bootmem_node(pgdat, size, align, goal, 0);
777 void * __init __alloc_bootmem_node_high(pg_data_t *pgdat, unsigned long size,
778 unsigned long align, unsigned long goal)
780 #ifdef MAX_DMA32_PFN
781 unsigned long end_pfn;
783 if (WARN_ON_ONCE(slab_is_available()))
784 return kzalloc_node(size, GFP_NOWAIT, pgdat->node_id);
786 /* update goal according ...MAX_DMA32_PFN */
787 end_pfn = pgdat->node_start_pfn + pgdat->node_spanned_pages;
789 if (end_pfn > MAX_DMA32_PFN + (128 >> (20 - PAGE_SHIFT)) &&
790 (goal >> PAGE_SHIFT) < MAX_DMA32_PFN) {
791 void *ptr;
792 unsigned long new_goal;
794 new_goal = MAX_DMA32_PFN << PAGE_SHIFT;
795 ptr = alloc_bootmem_bdata(pgdat->bdata, size, align,
796 new_goal, 0);
797 if (ptr)
798 return ptr;
800 #endif
802 return __alloc_bootmem_node(pgdat, size, align, goal);
806 #ifndef ARCH_LOW_ADDRESS_LIMIT
807 #define ARCH_LOW_ADDRESS_LIMIT 0xffffffffUL
808 #endif
811 * __alloc_bootmem_low - allocate low boot memory
812 * @size: size of the request in bytes
813 * @align: alignment of the region
814 * @goal: preferred starting address of the region
816 * The goal is dropped if it can not be satisfied and the allocation will
817 * fall back to memory below @goal.
819 * Allocation may happen on any node in the system.
821 * The function panics if the request can not be satisfied.
823 void * __init __alloc_bootmem_low(unsigned long size, unsigned long align,
824 unsigned long goal)
826 return ___alloc_bootmem(size, align, goal, ARCH_LOW_ADDRESS_LIMIT);
829 void * __init __alloc_bootmem_low_nopanic(unsigned long size,
830 unsigned long align,
831 unsigned long goal)
833 return ___alloc_bootmem_nopanic(size, align, goal,
834 ARCH_LOW_ADDRESS_LIMIT);
838 * __alloc_bootmem_low_node - allocate low boot memory from a specific node
839 * @pgdat: node to allocate from
840 * @size: size of the request in bytes
841 * @align: alignment of the region
842 * @goal: preferred starting address of the region
844 * The goal is dropped if it can not be satisfied and the allocation will
845 * fall back to memory below @goal.
847 * Allocation may fall back to any node in the system if the specified node
848 * can not hold the requested memory.
850 * The function panics if the request can not be satisfied.
852 void * __init __alloc_bootmem_low_node(pg_data_t *pgdat, unsigned long size,
853 unsigned long align, unsigned long goal)
855 if (WARN_ON_ONCE(slab_is_available()))
856 return kzalloc_node(size, GFP_NOWAIT, pgdat->node_id);
858 return ___alloc_bootmem_node(pgdat, size, align,
859 goal, ARCH_LOW_ADDRESS_LIMIT);