Root/mm/bootmem.c

1/*
2 * bootmem - A boot-time physical memory allocator and configurator
3 *
4 * Copyright (C) 1999 Ingo Molnar
5 * 1999 Kanoj Sarcar, SGI
6 * 2008 Johannes Weiner
7 *
8 * Access to this subsystem has to be serialized externally (which is true
9 * for the boot process anyway).
10 */
11#include <linux/init.h>
12#include <linux/pfn.h>
13#include <linux/slab.h>
14#include <linux/bootmem.h>
15#include <linux/module.h>
16#include <linux/kmemleak.h>
17#include <linux/range.h>
18#include <linux/memblock.h>
19
20#include <asm/bug.h>
21#include <asm/io.h>
22#include <asm/processor.h>
23
24#include "internal.h"
25
26#ifndef CONFIG_NEED_MULTIPLE_NODES
27struct pglist_data __refdata contig_page_data = {
28    .bdata = &bootmem_node_data[0]
29};
30EXPORT_SYMBOL(contig_page_data);
31#endif
32
33unsigned long max_low_pfn;
34unsigned long min_low_pfn;
35unsigned long max_pfn;
36
37bootmem_data_t bootmem_node_data[MAX_NUMNODES] __initdata;
38
39static struct list_head bdata_list __initdata = LIST_HEAD_INIT(bdata_list);
40
41static int bootmem_debug;
42
43static int __init bootmem_debug_setup(char *buf)
44{
45    bootmem_debug = 1;
46    return 0;
47}
48early_param("bootmem_debug", bootmem_debug_setup);
49
50#define bdebug(fmt, args...) ({ \
51    if (unlikely(bootmem_debug)) \
52        printk(KERN_INFO \
53            "bootmem::%s " fmt, \
54            __func__, ## args); \
55})
56
57static unsigned long __init bootmap_bytes(unsigned long pages)
58{
59    unsigned long bytes = (pages + 7) / 8;
60
61    return ALIGN(bytes, sizeof(long));
62}
63
64/**
65 * bootmem_bootmap_pages - calculate bitmap size in pages
66 * @pages: number of pages the bitmap has to represent
67 */
68unsigned long __init bootmem_bootmap_pages(unsigned long pages)
69{
70    unsigned long bytes = bootmap_bytes(pages);
71
72    return PAGE_ALIGN(bytes) >> PAGE_SHIFT;
73}
74
75/*
76 * link bdata in order
77 */
78static void __init link_bootmem(bootmem_data_t *bdata)
79{
80    struct list_head *iter;
81
82    list_for_each(iter, &bdata_list) {
83        bootmem_data_t *ent;
84
85        ent = list_entry(iter, bootmem_data_t, list);
86        if (bdata->node_min_pfn < ent->node_min_pfn)
87            break;
88    }
89    list_add_tail(&bdata->list, iter);
90}
91
92/*
93 * Called once to set up the allocator itself.
94 */
95static unsigned long __init init_bootmem_core(bootmem_data_t *bdata,
96    unsigned long mapstart, unsigned long start, unsigned long end)
97{
98    unsigned long mapsize;
99
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);
105
106    /*
107     * Initially all pages are reserved - setup_arch() has to
108     * register free RAM areas explicitly.
109     */
110    mapsize = bootmap_bytes(end - start);
111    memset(bdata->node_bootmem_map, 0xff, mapsize);
112
113    bdebug("nid=%td start=%lx map=%lx end=%lx mapsize=%lx\n",
114        bdata - bootmem_node_data, start, mapstart, end, mapsize);
115
116    return mapsize;
117}
118
119/**
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
125 *
126 * Returns the number of bytes needed to hold the bitmap for this node.
127 */
128unsigned long __init init_bootmem_node(pg_data_t *pgdat, unsigned long freepfn,
129                unsigned long startpfn, unsigned long endpfn)
130{
131    return init_bootmem_core(pgdat->bdata, freepfn, startpfn, endpfn);
132}
133
134/**
135 * init_bootmem - register boot memory
136 * @start: pfn where the bitmap is to be placed
137 * @pages: number of available physical pages
138 *
139 * Returns the number of bytes needed to hold the bitmap.
140 */
141unsigned long __init init_bootmem(unsigned long start, unsigned long pages)
142{
143    max_low_pfn = pages;
144    min_low_pfn = start;
145    return init_bootmem_core(NODE_DATA(0)->bdata, start, 0, pages);
146}
147
148/*
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
152 *
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.
156 */
157void __init free_bootmem_late(unsigned long addr, unsigned long size)
158{
159    unsigned long cursor, end;
160
161    kmemleak_free_part(__va(addr), size);
162
163    cursor = PFN_UP(addr);
164    end = PFN_DOWN(addr + size);
165
166    for (; cursor < end; cursor++) {
167        __free_pages_bootmem(pfn_to_page(cursor), 0);
168        totalram_pages++;
169    }
170}
171
172static unsigned long __init free_all_bootmem_core(bootmem_data_t *bdata)
173{
174    int aligned;
175    struct page *page;
176    unsigned long start, end, pages, count = 0;
177
178    if (!bdata->node_bootmem_map)
179        return 0;
180
181    start = bdata->node_min_pfn;
182    end = bdata->node_low_pfn;
183
184    /*
185     * If the start is aligned to the machines wordsize, we might
186     * be able to free pages in bulks of that order.
187     */
188    aligned = !(start & (BITS_PER_LONG - 1));
189
190    bdebug("nid=%td start=%lx end=%lx aligned=%d\n",
191        bdata - bootmem_node_data, start, end, aligned);
192
193    while (start < end) {
194        unsigned long *map, idx, vec;
195
196        map = bdata->node_bootmem_map;
197        idx = start - bdata->node_min_pfn;
198        vec = ~map[idx / BITS_PER_LONG];
199
200        if (aligned && vec == ~0UL && start + BITS_PER_LONG < end) {
201            int order = ilog2(BITS_PER_LONG);
202
203            __free_pages_bootmem(pfn_to_page(start), order);
204            count += BITS_PER_LONG;
205        } else {
206            unsigned long off = 0;
207
208            while (vec && off < BITS_PER_LONG) {
209                if (vec & 1) {
210                    page = pfn_to_page(start + off);
211                    __free_pages_bootmem(page, 0);
212                    count++;
213                }
214                vec >>= 1;
215                off++;
216            }
217        }
218        start += BITS_PER_LONG;
219    }
220
221    page = virt_to_page(bdata->node_bootmem_map);
222    pages = bdata->node_low_pfn - bdata->node_min_pfn;
223    pages = bootmem_bootmap_pages(pages);
224    count += pages;
225    while (pages--)
226        __free_pages_bootmem(page++, 0);
227
228    bdebug("nid=%td released=%lx\n", bdata - bootmem_node_data, count);
229
230    return count;
231}
232
233/**
234 * free_all_bootmem_node - release a node's free pages to the buddy allocator
235 * @pgdat: node to be released
236 *
237 * Returns the number of pages actually released.
238 */
239unsigned long __init free_all_bootmem_node(pg_data_t *pgdat)
240{
241    register_page_bootmem_info_node(pgdat);
242    return free_all_bootmem_core(pgdat->bdata);
243}
244
245/**
246 * free_all_bootmem - release free pages to the buddy allocator
247 *
248 * Returns the number of pages actually released.
249 */
250unsigned long __init free_all_bootmem(void)
251{
252    unsigned long total_pages = 0;
253    bootmem_data_t *bdata;
254
255    list_for_each_entry(bdata, &bdata_list, list)
256        total_pages += free_all_bootmem_core(bdata);
257
258    return total_pages;
259}
260
261static void __init __free(bootmem_data_t *bdata,
262            unsigned long sidx, unsigned long eidx)
263{
264    unsigned long idx;
265
266    bdebug("nid=%td start=%lx end=%lx\n", bdata - bootmem_node_data,
267        sidx + bdata->node_min_pfn,
268        eidx + bdata->node_min_pfn);
269
270    if (bdata->hint_idx > sidx)
271        bdata->hint_idx = sidx;
272
273    for (idx = sidx; idx < eidx; idx++)
274        if (!test_and_clear_bit(idx, bdata->node_bootmem_map))
275            BUG();
276}
277
278static int __init __reserve(bootmem_data_t *bdata, unsigned long sidx,
279            unsigned long eidx, int flags)
280{
281    unsigned long idx;
282    int exclusive = flags & BOOTMEM_EXCLUSIVE;
283
284    bdebug("nid=%td start=%lx end=%lx flags=%x\n",
285        bdata - bootmem_node_data,
286        sidx + bdata->node_min_pfn,
287        eidx + bdata->node_min_pfn,
288        flags);
289
290    for (idx = sidx; idx < eidx; idx++)
291        if (test_and_set_bit(idx, bdata->node_bootmem_map)) {
292            if (exclusive) {
293                __free(bdata, sidx, idx);
294                return -EBUSY;
295            }
296            bdebug("silent double reserve of PFN %lx\n",
297                idx + bdata->node_min_pfn);
298        }
299    return 0;
300}
301
302static int __init mark_bootmem_node(bootmem_data_t *bdata,
303                unsigned long start, unsigned long end,
304                int reserve, int flags)
305{
306    unsigned long sidx, eidx;
307
308    bdebug("nid=%td start=%lx end=%lx reserve=%d flags=%x\n",
309        bdata - bootmem_node_data, start, end, reserve, flags);
310
311    BUG_ON(start < bdata->node_min_pfn);
312    BUG_ON(end > bdata->node_low_pfn);
313
314    sidx = start - bdata->node_min_pfn;
315    eidx = end - bdata->node_min_pfn;
316
317    if (reserve)
318        return __reserve(bdata, sidx, eidx, flags);
319    else
320        __free(bdata, sidx, eidx);
321    return 0;
322}
323
324static int __init mark_bootmem(unsigned long start, unsigned long end,
325                int reserve, int flags)
326{
327    unsigned long pos;
328    bootmem_data_t *bdata;
329
330    pos = start;
331    list_for_each_entry(bdata, &bdata_list, list) {
332        int err;
333        unsigned long max;
334
335        if (pos < bdata->node_min_pfn ||
336            pos >= bdata->node_low_pfn) {
337            BUG_ON(pos != start);
338            continue;
339        }
340
341        max = min(bdata->node_low_pfn, end);
342
343        err = mark_bootmem_node(bdata, pos, max, reserve, flags);
344        if (reserve && err) {
345            mark_bootmem(start, pos, 0, 0);
346            return err;
347        }
348
349        if (max == end)
350            return 0;
351        pos = bdata->node_low_pfn;
352    }
353    BUG();
354}
355
356/**
357 * free_bootmem_node - mark a page range as usable
358 * @pgdat: node the range resides on
359 * @physaddr: starting address of the range
360 * @size: size of the range in bytes
361 *
362 * Partial pages will be considered reserved and left as they are.
363 *
364 * The range must reside completely on the specified node.
365 */
366void __init free_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
367                  unsigned long size)
368{
369    unsigned long start, end;
370
371    kmemleak_free_part(__va(physaddr), size);
372
373    start = PFN_UP(physaddr);
374    end = PFN_DOWN(physaddr + size);
375
376    mark_bootmem_node(pgdat->bdata, start, end, 0, 0);
377}
378
379/**
380 * free_bootmem - mark a page range as usable
381 * @addr: starting address of the range
382 * @size: size of the range in bytes
383 *
384 * Partial pages will be considered reserved and left as they are.
385 *
386 * The range must be contiguous but may span node boundaries.
387 */
388void __init free_bootmem(unsigned long addr, unsigned long size)
389{
390    unsigned long start, end;
391
392    kmemleak_free_part(__va(addr), size);
393
394    start = PFN_UP(addr);
395    end = PFN_DOWN(addr + size);
396
397    mark_bootmem(start, end, 0, 0);
398}
399
400/**
401 * reserve_bootmem_node - mark a page range as reserved
402 * @pgdat: node the range resides on
403 * @physaddr: starting address of the range
404 * @size: size of the range in bytes
405 * @flags: reservation flags (see linux/bootmem.h)
406 *
407 * Partial pages will be reserved.
408 *
409 * The range must reside completely on the specified node.
410 */
411int __init reserve_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
412                 unsigned long size, int flags)
413{
414    unsigned long start, end;
415
416    start = PFN_DOWN(physaddr);
417    end = PFN_UP(physaddr + size);
418
419    return mark_bootmem_node(pgdat->bdata, start, end, 1, flags);
420}
421
422/**
423 * reserve_bootmem - mark a page range as usable
424 * @addr: starting address of the range
425 * @size: size of the range in bytes
426 * @flags: reservation flags (see linux/bootmem.h)
427 *
428 * Partial pages will be reserved.
429 *
430 * The range must be contiguous but may span node boundaries.
431 */
432int __init reserve_bootmem(unsigned long addr, unsigned long size,
433                int flags)
434{
435    unsigned long start, end;
436
437    start = PFN_DOWN(addr);
438    end = PFN_UP(addr + size);
439
440    return mark_bootmem(start, end, 1, flags);
441}
442
443int __weak __init reserve_bootmem_generic(unsigned long phys, unsigned long len,
444                   int flags)
445{
446    return reserve_bootmem(phys, len, flags);
447}
448
449static unsigned long __init align_idx(struct bootmem_data *bdata,
450                      unsigned long idx, unsigned long step)
451{
452    unsigned long base = bdata->node_min_pfn;
453
454    /*
455     * Align the index with respect to the node start so that the
456     * combination of both satisfies the requested alignment.
457     */
458
459    return ALIGN(base + idx, step) - base;
460}
461
462static unsigned long __init align_off(struct bootmem_data *bdata,
463                      unsigned long off, unsigned long align)
464{
465    unsigned long base = PFN_PHYS(bdata->node_min_pfn);
466
467    /* Same as align_idx for byte offsets */
468
469    return ALIGN(base + off, align) - base;
470}
471
472static void * __init alloc_bootmem_core(struct bootmem_data *bdata,
473                    unsigned long size, unsigned long align,
474                    unsigned long goal, unsigned long limit)
475{
476    unsigned long fallback = 0;
477    unsigned long min, max, start, sidx, midx, step;
478
479    bdebug("nid=%td size=%lx [%lu pages] align=%lx goal=%lx limit=%lx\n",
480        bdata - bootmem_node_data, size, PAGE_ALIGN(size) >> PAGE_SHIFT,
481        align, goal, limit);
482
483    BUG_ON(!size);
484    BUG_ON(align & (align - 1));
485    BUG_ON(limit && goal + size > limit);
486
487    if (!bdata->node_bootmem_map)
488        return NULL;
489
490    min = bdata->node_min_pfn;
491    max = bdata->node_low_pfn;
492
493    goal >>= PAGE_SHIFT;
494    limit >>= PAGE_SHIFT;
495
496    if (limit && max > limit)
497        max = limit;
498    if (max <= min)
499        return NULL;
500
501    step = max(align >> PAGE_SHIFT, 1UL);
502
503    if (goal && min < goal && goal < max)
504        start = ALIGN(goal, step);
505    else
506        start = ALIGN(min, step);
507
508    sidx = start - bdata->node_min_pfn;
509    midx = max - bdata->node_min_pfn;
510
511    if (bdata->hint_idx > sidx) {
512        /*
513         * Handle the valid case of sidx being zero and still
514         * catch the fallback below.
515         */
516        fallback = sidx + 1;
517        sidx = align_idx(bdata, bdata->hint_idx, step);
518    }
519
520    while (1) {
521        int merge;
522        void *region;
523        unsigned long eidx, i, start_off, end_off;
524find_block:
525        sidx = find_next_zero_bit(bdata->node_bootmem_map, midx, sidx);
526        sidx = align_idx(bdata, sidx, step);
527        eidx = sidx + PFN_UP(size);
528
529        if (sidx >= midx || eidx > midx)
530            break;
531
532        for (i = sidx; i < eidx; i++)
533            if (test_bit(i, bdata->node_bootmem_map)) {
534                sidx = align_idx(bdata, i, step);
535                if (sidx == i)
536                    sidx += step;
537                goto find_block;
538            }
539
540        if (bdata->last_end_off & (PAGE_SIZE - 1) &&
541                PFN_DOWN(bdata->last_end_off) + 1 == sidx)
542            start_off = align_off(bdata, bdata->last_end_off, align);
543        else
544            start_off = PFN_PHYS(sidx);
545
546        merge = PFN_DOWN(start_off) < sidx;
547        end_off = start_off + size;
548
549        bdata->last_end_off = end_off;
550        bdata->hint_idx = PFN_UP(end_off);
551
552        /*
553         * Reserve the area now:
554         */
555        if (__reserve(bdata, PFN_DOWN(start_off) + merge,
556                PFN_UP(end_off), BOOTMEM_EXCLUSIVE))
557            BUG();
558
559        region = phys_to_virt(PFN_PHYS(bdata->node_min_pfn) +
560                start_off);
561        memset(region, 0, size);
562        /*
563         * The min_count is set to 0 so that bootmem allocated blocks
564         * are never reported as leaks.
565         */
566        kmemleak_alloc(region, size, 0, 0);
567        return region;
568    }
569
570    if (fallback) {
571        sidx = align_idx(bdata, fallback - 1, step);
572        fallback = 0;
573        goto find_block;
574    }
575
576    return NULL;
577}
578
579static void * __init alloc_arch_preferred_bootmem(bootmem_data_t *bdata,
580                    unsigned long size, unsigned long align,
581                    unsigned long goal, unsigned long limit)
582{
583    if (WARN_ON_ONCE(slab_is_available()))
584        return kzalloc(size, GFP_NOWAIT);
585
586#ifdef CONFIG_HAVE_ARCH_BOOTMEM
587    {
588        bootmem_data_t *p_bdata;
589
590        p_bdata = bootmem_arch_preferred_node(bdata, size, align,
591                            goal, limit);
592        if (p_bdata)
593            return alloc_bootmem_core(p_bdata, size, align,
594                            goal, limit);
595    }
596#endif
597    return NULL;
598}
599
600static void * __init ___alloc_bootmem_nopanic(unsigned long size,
601                    unsigned long align,
602                    unsigned long goal,
603                    unsigned long limit)
604{
605    bootmem_data_t *bdata;
606    void *region;
607
608restart:
609    region = alloc_arch_preferred_bootmem(NULL, size, align, goal, limit);
610    if (region)
611        return region;
612
613    list_for_each_entry(bdata, &bdata_list, list) {
614        if (goal && bdata->node_low_pfn <= PFN_DOWN(goal))
615            continue;
616        if (limit && bdata->node_min_pfn >= PFN_DOWN(limit))
617            break;
618
619        region = alloc_bootmem_core(bdata, size, align, goal, limit);
620        if (region)
621            return region;
622    }
623
624    if (goal) {
625        goal = 0;
626        goto restart;
627    }
628
629    return NULL;
630}
631
632/**
633 * __alloc_bootmem_nopanic - allocate boot memory without panicking
634 * @size: size of the request in bytes
635 * @align: alignment of the region
636 * @goal: preferred starting address of the region
637 *
638 * The goal is dropped if it can not be satisfied and the allocation will
639 * fall back to memory below @goal.
640 *
641 * Allocation may happen on any node in the system.
642 *
643 * Returns NULL on failure.
644 */
645void * __init __alloc_bootmem_nopanic(unsigned long size, unsigned long align,
646                    unsigned long goal)
647{
648    unsigned long limit = 0;
649
650    return ___alloc_bootmem_nopanic(size, align, goal, limit);
651}
652
653static void * __init ___alloc_bootmem(unsigned long size, unsigned long align,
654                    unsigned long goal, unsigned long limit)
655{
656    void *mem = ___alloc_bootmem_nopanic(size, align, goal, limit);
657
658    if (mem)
659        return mem;
660    /*
661     * Whoops, we cannot satisfy the allocation request.
662     */
663    printk(KERN_ALERT "bootmem alloc of %lu bytes failed!\n", size);
664    panic("Out of memory");
665    return NULL;
666}
667
668/**
669 * __alloc_bootmem - allocate boot memory
670 * @size: size of the request in bytes
671 * @align: alignment of the region
672 * @goal: preferred starting address of the region
673 *
674 * The goal is dropped if it can not be satisfied and the allocation will
675 * fall back to memory below @goal.
676 *
677 * Allocation may happen on any node in the system.
678 *
679 * The function panics if the request can not be satisfied.
680 */
681void * __init __alloc_bootmem(unsigned long size, unsigned long align,
682                  unsigned long goal)
683{
684    unsigned long limit = 0;
685
686    return ___alloc_bootmem(size, align, goal, limit);
687}
688
689static void * __init ___alloc_bootmem_node(bootmem_data_t *bdata,
690                unsigned long size, unsigned long align,
691                unsigned long goal, unsigned long limit)
692{
693    void *ptr;
694
695    ptr = alloc_arch_preferred_bootmem(bdata, size, align, goal, limit);
696    if (ptr)
697        return ptr;
698
699    ptr = alloc_bootmem_core(bdata, size, align, goal, limit);
700    if (ptr)
701        return ptr;
702
703    return ___alloc_bootmem(size, align, goal, limit);
704}
705
706/**
707 * __alloc_bootmem_node - allocate boot memory from a specific node
708 * @pgdat: node to allocate from
709 * @size: size of the request in bytes
710 * @align: alignment of the region
711 * @goal: preferred starting address of the region
712 *
713 * The goal is dropped if it can not be satisfied and the allocation will
714 * fall back to memory below @goal.
715 *
716 * Allocation may fall back to any node in the system if the specified node
717 * can not hold the requested memory.
718 *
719 * The function panics if the request can not be satisfied.
720 */
721void * __init __alloc_bootmem_node(pg_data_t *pgdat, unsigned long size,
722                   unsigned long align, unsigned long goal)
723{
724    if (WARN_ON_ONCE(slab_is_available()))
725        return kzalloc_node(size, GFP_NOWAIT, pgdat->node_id);
726
727    return ___alloc_bootmem_node(pgdat->bdata, size, align, goal, 0);
728}
729
730void * __init __alloc_bootmem_node_high(pg_data_t *pgdat, unsigned long size,
731                   unsigned long align, unsigned long goal)
732{
733#ifdef MAX_DMA32_PFN
734    unsigned long end_pfn;
735
736    if (WARN_ON_ONCE(slab_is_available()))
737        return kzalloc_node(size, GFP_NOWAIT, pgdat->node_id);
738
739    /* update goal according ...MAX_DMA32_PFN */
740    end_pfn = pgdat->node_start_pfn + pgdat->node_spanned_pages;
741
742    if (end_pfn > MAX_DMA32_PFN + (128 >> (20 - PAGE_SHIFT)) &&
743        (goal >> PAGE_SHIFT) < MAX_DMA32_PFN) {
744        void *ptr;
745        unsigned long new_goal;
746
747        new_goal = MAX_DMA32_PFN << PAGE_SHIFT;
748        ptr = alloc_bootmem_core(pgdat->bdata, size, align,
749                         new_goal, 0);
750        if (ptr)
751            return ptr;
752    }
753#endif
754
755    return __alloc_bootmem_node(pgdat, size, align, goal);
756
757}
758
759#ifdef CONFIG_SPARSEMEM
760/**
761 * alloc_bootmem_section - allocate boot memory from a specific section
762 * @size: size of the request in bytes
763 * @section_nr: sparse map section to allocate from
764 *
765 * Return NULL on failure.
766 */
767void * __init alloc_bootmem_section(unsigned long size,
768                    unsigned long section_nr)
769{
770    bootmem_data_t *bdata;
771    unsigned long pfn, goal, limit;
772
773    pfn = section_nr_to_pfn(section_nr);
774    goal = pfn << PAGE_SHIFT;
775    limit = section_nr_to_pfn(section_nr + 1) << PAGE_SHIFT;
776    bdata = &bootmem_node_data[early_pfn_to_nid(pfn)];
777
778    return alloc_bootmem_core(bdata, size, SMP_CACHE_BYTES, goal, limit);
779}
780#endif
781
782void * __init __alloc_bootmem_node_nopanic(pg_data_t *pgdat, unsigned long size,
783                   unsigned long align, unsigned long goal)
784{
785    void *ptr;
786
787    if (WARN_ON_ONCE(slab_is_available()))
788        return kzalloc_node(size, GFP_NOWAIT, pgdat->node_id);
789
790    ptr = alloc_arch_preferred_bootmem(pgdat->bdata, size, align, goal, 0);
791    if (ptr)
792        return ptr;
793
794    ptr = alloc_bootmem_core(pgdat->bdata, size, align, goal, 0);
795    if (ptr)
796        return ptr;
797
798    return __alloc_bootmem_nopanic(size, align, goal);
799}
800
801#ifndef ARCH_LOW_ADDRESS_LIMIT
802#define ARCH_LOW_ADDRESS_LIMIT 0xffffffffUL
803#endif
804
805/**
806 * __alloc_bootmem_low - allocate low boot memory
807 * @size: size of the request in bytes
808 * @align: alignment of the region
809 * @goal: preferred starting address of the region
810 *
811 * The goal is dropped if it can not be satisfied and the allocation will
812 * fall back to memory below @goal.
813 *
814 * Allocation may happen on any node in the system.
815 *
816 * The function panics if the request can not be satisfied.
817 */
818void * __init __alloc_bootmem_low(unsigned long size, unsigned long align,
819                  unsigned long goal)
820{
821    return ___alloc_bootmem(size, align, goal, ARCH_LOW_ADDRESS_LIMIT);
822}
823
824/**
825 * __alloc_bootmem_low_node - allocate low boot memory from a specific node
826 * @pgdat: node to allocate from
827 * @size: size of the request in bytes
828 * @align: alignment of the region
829 * @goal: preferred starting address of the region
830 *
831 * The goal is dropped if it can not be satisfied and the allocation will
832 * fall back to memory below @goal.
833 *
834 * Allocation may fall back to any node in the system if the specified node
835 * can not hold the requested memory.
836 *
837 * The function panics if the request can not be satisfied.
838 */
839void * __init __alloc_bootmem_low_node(pg_data_t *pgdat, unsigned long size,
840                       unsigned long align, unsigned long goal)
841{
842    if (WARN_ON_ONCE(slab_is_available()))
843        return kzalloc_node(size, GFP_NOWAIT, pgdat->node_id);
844
845    return ___alloc_bootmem_node(pgdat->bdata, size, align,
846                goal, ARCH_LOW_ADDRESS_LIMIT);
847}
848

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