https://github.com/torvalds/linux
Revision cc87317726f851531ae8422e0c2d3d6e2d7b1955 authored by Johannes Weiner on 27 February 2015, 23:52:09 UTC, committed by Linus Torvalds on 28 February 2015, 17:57:51 UTC
Historically, !__GFP_FS allocations were not allowed to invoke the OOM
killer once reclaim had failed, but nevertheless kept looping in the
allocator.

Commit 9879de7373fc ("mm: page_alloc: embed OOM killing naturally into
allocation slowpath"), which should have been a simple cleanup patch,
accidentally changed the behavior to aborting the allocation at that
point.  This creates problems with filesystem callers (?) that currently
rely on the allocator waiting for other tasks to intervene.

Revert the behavior as it shouldn't have been changed as part of a
cleanup patch.

Fixes: 9879de7373fc ("mm: page_alloc: embed OOM killing naturally into allocation slowpath")
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Dave Chinner <david@fromorbit.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: <stable@vger.kernel.org>	[3.19.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 39afb5e
Raw File
Tip revision: cc87317726f851531ae8422e0c2d3d6e2d7b1955 authored by Johannes Weiner on 27 February 2015, 23:52:09 UTC
mm: page_alloc: revert inadvertent !__GFP_FS retry behavior change
Tip revision: cc87317
bootmem.c
/*
 *  bootmem - A boot-time physical memory allocator and configurator
 *
 *  Copyright (C) 1999 Ingo Molnar
 *                1999 Kanoj Sarcar, SGI
 *                2008 Johannes Weiner
 *
 * Access to this subsystem has to be serialized externally (which is true
 * for the boot process anyway).
 */
#include <linux/init.h>
#include <linux/pfn.h>
#include <linux/slab.h>
#include <linux/bootmem.h>
#include <linux/export.h>
#include <linux/kmemleak.h>
#include <linux/range.h>
#include <linux/memblock.h>
#include <linux/bug.h>
#include <linux/io.h>

#include <asm/processor.h>

#include "internal.h"

#ifndef CONFIG_NEED_MULTIPLE_NODES
struct pglist_data __refdata contig_page_data = {
	.bdata = &bootmem_node_data[0]
};
EXPORT_SYMBOL(contig_page_data);
#endif

unsigned long max_low_pfn;
unsigned long min_low_pfn;
unsigned long max_pfn;

bootmem_data_t bootmem_node_data[MAX_NUMNODES] __initdata;

static struct list_head bdata_list __initdata = LIST_HEAD_INIT(bdata_list);

static int bootmem_debug;

static int __init bootmem_debug_setup(char *buf)
{
	bootmem_debug = 1;
	return 0;
}
early_param("bootmem_debug", bootmem_debug_setup);

#define bdebug(fmt, args...) ({				\
	if (unlikely(bootmem_debug))			\
		printk(KERN_INFO			\
			"bootmem::%s " fmt,		\
			__func__, ## args);		\
})

static unsigned long __init bootmap_bytes(unsigned long pages)
{
	unsigned long bytes = DIV_ROUND_UP(pages, 8);

	return ALIGN(bytes, sizeof(long));
}

/**
 * bootmem_bootmap_pages - calculate bitmap size in pages
 * @pages: number of pages the bitmap has to represent
 */
unsigned long __init bootmem_bootmap_pages(unsigned long pages)
{
	unsigned long bytes = bootmap_bytes(pages);

	return PAGE_ALIGN(bytes) >> PAGE_SHIFT;
}

/*
 * link bdata in order
 */
static void __init link_bootmem(bootmem_data_t *bdata)
{
	bootmem_data_t *ent;

	list_for_each_entry(ent, &bdata_list, list) {
		if (bdata->node_min_pfn < ent->node_min_pfn) {
			list_add_tail(&bdata->list, &ent->list);
			return;
		}
	}

	list_add_tail(&bdata->list, &bdata_list);
}

/*
 * Called once to set up the allocator itself.
 */
static unsigned long __init init_bootmem_core(bootmem_data_t *bdata,
	unsigned long mapstart, unsigned long start, unsigned long end)
{
	unsigned long mapsize;

	mminit_validate_memmodel_limits(&start, &end);
	bdata->node_bootmem_map = phys_to_virt(PFN_PHYS(mapstart));
	bdata->node_min_pfn = start;
	bdata->node_low_pfn = end;
	link_bootmem(bdata);

	/*
	 * Initially all pages are reserved - setup_arch() has to
	 * register free RAM areas explicitly.
	 */
	mapsize = bootmap_bytes(end - start);
	memset(bdata->node_bootmem_map, 0xff, mapsize);

	bdebug("nid=%td start=%lx map=%lx end=%lx mapsize=%lx\n",
		bdata - bootmem_node_data, start, mapstart, end, mapsize);

	return mapsize;
}

/**
 * init_bootmem_node - register a node as boot memory
 * @pgdat: node to register
 * @freepfn: pfn where the bitmap for this node is to be placed
 * @startpfn: first pfn on the node
 * @endpfn: first pfn after the node
 *
 * Returns the number of bytes needed to hold the bitmap for this node.
 */
unsigned long __init init_bootmem_node(pg_data_t *pgdat, unsigned long freepfn,
				unsigned long startpfn, unsigned long endpfn)
{
	return init_bootmem_core(pgdat->bdata, freepfn, startpfn, endpfn);
}

/**
 * init_bootmem - register boot memory
 * @start: pfn where the bitmap is to be placed
 * @pages: number of available physical pages
 *
 * Returns the number of bytes needed to hold the bitmap.
 */
unsigned long __init init_bootmem(unsigned long start, unsigned long pages)
{
	max_low_pfn = pages;
	min_low_pfn = start;
	return init_bootmem_core(NODE_DATA(0)->bdata, start, 0, pages);
}

/*
 * free_bootmem_late - free bootmem pages directly to page allocator
 * @addr: starting physical address of the range
 * @size: size of the range in bytes
 *
 * This is only useful when the bootmem allocator has already been torn
 * down, but we are still initializing the system.  Pages are given directly
 * to the page allocator, no bootmem metadata is updated because it is gone.
 */
void __init free_bootmem_late(unsigned long physaddr, unsigned long size)
{
	unsigned long cursor, end;

	kmemleak_free_part(__va(physaddr), size);

	cursor = PFN_UP(physaddr);
	end = PFN_DOWN(physaddr + size);

	for (; cursor < end; cursor++) {
		__free_pages_bootmem(pfn_to_page(cursor), 0);
		totalram_pages++;
	}
}

static unsigned long __init free_all_bootmem_core(bootmem_data_t *bdata)
{
	struct page *page;
	unsigned long *map, start, end, pages, count = 0;

	if (!bdata->node_bootmem_map)
		return 0;

	map = bdata->node_bootmem_map;
	start = bdata->node_min_pfn;
	end = bdata->node_low_pfn;

	bdebug("nid=%td start=%lx end=%lx\n",
		bdata - bootmem_node_data, start, end);

	while (start < end) {
		unsigned long idx, vec;
		unsigned shift;

		idx = start - bdata->node_min_pfn;
		shift = idx & (BITS_PER_LONG - 1);
		/*
		 * vec holds at most BITS_PER_LONG map bits,
		 * bit 0 corresponds to start.
		 */
		vec = ~map[idx / BITS_PER_LONG];

		if (shift) {
			vec >>= shift;
			if (end - start >= BITS_PER_LONG)
				vec |= ~map[idx / BITS_PER_LONG + 1] <<
					(BITS_PER_LONG - shift);
		}
		/*
		 * If we have a properly aligned and fully unreserved
		 * BITS_PER_LONG block of pages in front of us, free
		 * it in one go.
		 */
		if (IS_ALIGNED(start, BITS_PER_LONG) && vec == ~0UL) {
			int order = ilog2(BITS_PER_LONG);

			__free_pages_bootmem(pfn_to_page(start), order);
			count += BITS_PER_LONG;
			start += BITS_PER_LONG;
		} else {
			unsigned long cur = start;

			start = ALIGN(start + 1, BITS_PER_LONG);
			while (vec && cur != start) {
				if (vec & 1) {
					page = pfn_to_page(cur);
					__free_pages_bootmem(page, 0);
					count++;
				}
				vec >>= 1;
				++cur;
			}
		}
	}

	page = virt_to_page(bdata->node_bootmem_map);
	pages = bdata->node_low_pfn - bdata->node_min_pfn;
	pages = bootmem_bootmap_pages(pages);
	count += pages;
	while (pages--)
		__free_pages_bootmem(page++, 0);

	bdebug("nid=%td released=%lx\n", bdata - bootmem_node_data, count);

	return count;
}

static int reset_managed_pages_done __initdata;

void reset_node_managed_pages(pg_data_t *pgdat)
{
	struct zone *z;

	for (z = pgdat->node_zones; z < pgdat->node_zones + MAX_NR_ZONES; z++)
		z->managed_pages = 0;
}

void __init reset_all_zones_managed_pages(void)
{
	struct pglist_data *pgdat;

	if (reset_managed_pages_done)
		return;

	for_each_online_pgdat(pgdat)
		reset_node_managed_pages(pgdat);

	reset_managed_pages_done = 1;
}

/**
 * free_all_bootmem - release free pages to the buddy allocator
 *
 * Returns the number of pages actually released.
 */
unsigned long __init free_all_bootmem(void)
{
	unsigned long total_pages = 0;
	bootmem_data_t *bdata;

	reset_all_zones_managed_pages();

	list_for_each_entry(bdata, &bdata_list, list)
		total_pages += free_all_bootmem_core(bdata);

	totalram_pages += total_pages;

	return total_pages;
}

static void __init __free(bootmem_data_t *bdata,
			unsigned long sidx, unsigned long eidx)
{
	unsigned long idx;

	bdebug("nid=%td start=%lx end=%lx\n", bdata - bootmem_node_data,
		sidx + bdata->node_min_pfn,
		eidx + bdata->node_min_pfn);

	if (bdata->hint_idx > sidx)
		bdata->hint_idx = sidx;

	for (idx = sidx; idx < eidx; idx++)
		if (!test_and_clear_bit(idx, bdata->node_bootmem_map))
			BUG();
}

static int __init __reserve(bootmem_data_t *bdata, unsigned long sidx,
			unsigned long eidx, int flags)
{
	unsigned long idx;
	int exclusive = flags & BOOTMEM_EXCLUSIVE;

	bdebug("nid=%td start=%lx end=%lx flags=%x\n",
		bdata - bootmem_node_data,
		sidx + bdata->node_min_pfn,
		eidx + bdata->node_min_pfn,
		flags);

	for (idx = sidx; idx < eidx; idx++)
		if (test_and_set_bit(idx, bdata->node_bootmem_map)) {
			if (exclusive) {
				__free(bdata, sidx, idx);
				return -EBUSY;
			}
			bdebug("silent double reserve of PFN %lx\n",
				idx + bdata->node_min_pfn);
		}
	return 0;
}

static int __init mark_bootmem_node(bootmem_data_t *bdata,
				unsigned long start, unsigned long end,
				int reserve, int flags)
{
	unsigned long sidx, eidx;

	bdebug("nid=%td start=%lx end=%lx reserve=%d flags=%x\n",
		bdata - bootmem_node_data, start, end, reserve, flags);

	BUG_ON(start < bdata->node_min_pfn);
	BUG_ON(end > bdata->node_low_pfn);

	sidx = start - bdata->node_min_pfn;
	eidx = end - bdata->node_min_pfn;

	if (reserve)
		return __reserve(bdata, sidx, eidx, flags);
	else
		__free(bdata, sidx, eidx);
	return 0;
}

static int __init mark_bootmem(unsigned long start, unsigned long end,
				int reserve, int flags)
{
	unsigned long pos;
	bootmem_data_t *bdata;

	pos = start;
	list_for_each_entry(bdata, &bdata_list, list) {
		int err;
		unsigned long max;

		if (pos < bdata->node_min_pfn ||
		    pos >= bdata->node_low_pfn) {
			BUG_ON(pos != start);
			continue;
		}

		max = min(bdata->node_low_pfn, end);

		err = mark_bootmem_node(bdata, pos, max, reserve, flags);
		if (reserve && err) {
			mark_bootmem(start, pos, 0, 0);
			return err;
		}

		if (max == end)
			return 0;
		pos = bdata->node_low_pfn;
	}
	BUG();
}

/**
 * free_bootmem_node - mark a page range as usable
 * @pgdat: node the range resides on
 * @physaddr: starting address of the range
 * @size: size of the range in bytes
 *
 * Partial pages will be considered reserved and left as they are.
 *
 * The range must reside completely on the specified node.
 */
void __init free_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
			      unsigned long size)
{
	unsigned long start, end;

	kmemleak_free_part(__va(physaddr), size);

	start = PFN_UP(physaddr);
	end = PFN_DOWN(physaddr + size);

	mark_bootmem_node(pgdat->bdata, start, end, 0, 0);
}

/**
 * free_bootmem - mark a page range as usable
 * @addr: starting physical address of the range
 * @size: size of the range in bytes
 *
 * Partial pages will be considered reserved and left as they are.
 *
 * The range must be contiguous but may span node boundaries.
 */
void __init free_bootmem(unsigned long physaddr, unsigned long size)
{
	unsigned long start, end;

	kmemleak_free_part(__va(physaddr), size);

	start = PFN_UP(physaddr);
	end = PFN_DOWN(physaddr + size);

	mark_bootmem(start, end, 0, 0);
}

/**
 * reserve_bootmem_node - mark a page range as reserved
 * @pgdat: node the range resides on
 * @physaddr: starting address of the range
 * @size: size of the range in bytes
 * @flags: reservation flags (see linux/bootmem.h)
 *
 * Partial pages will be reserved.
 *
 * The range must reside completely on the specified node.
 */
int __init reserve_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
				 unsigned long size, int flags)
{
	unsigned long start, end;

	start = PFN_DOWN(physaddr);
	end = PFN_UP(physaddr + size);

	return mark_bootmem_node(pgdat->bdata, start, end, 1, flags);
}

/**
 * reserve_bootmem - mark a page range as reserved
 * @addr: starting address of the range
 * @size: size of the range in bytes
 * @flags: reservation flags (see linux/bootmem.h)
 *
 * Partial pages will be reserved.
 *
 * The range must be contiguous but may span node boundaries.
 */
int __init reserve_bootmem(unsigned long addr, unsigned long size,
			    int flags)
{
	unsigned long start, end;

	start = PFN_DOWN(addr);
	end = PFN_UP(addr + size);

	return mark_bootmem(start, end, 1, flags);
}

static unsigned long __init align_idx(struct bootmem_data *bdata,
				      unsigned long idx, unsigned long step)
{
	unsigned long base = bdata->node_min_pfn;

	/*
	 * Align the index with respect to the node start so that the
	 * combination of both satisfies the requested alignment.
	 */

	return ALIGN(base + idx, step) - base;
}

static unsigned long __init align_off(struct bootmem_data *bdata,
				      unsigned long off, unsigned long align)
{
	unsigned long base = PFN_PHYS(bdata->node_min_pfn);

	/* Same as align_idx for byte offsets */

	return ALIGN(base + off, align) - base;
}

static void * __init alloc_bootmem_bdata(struct bootmem_data *bdata,
					unsigned long size, unsigned long align,
					unsigned long goal, unsigned long limit)
{
	unsigned long fallback = 0;
	unsigned long min, max, start, sidx, midx, step;

	bdebug("nid=%td size=%lx [%lu pages] align=%lx goal=%lx limit=%lx\n",
		bdata - bootmem_node_data, size, PAGE_ALIGN(size) >> PAGE_SHIFT,
		align, goal, limit);

	BUG_ON(!size);
	BUG_ON(align & (align - 1));
	BUG_ON(limit && goal + size > limit);

	if (!bdata->node_bootmem_map)
		return NULL;

	min = bdata->node_min_pfn;
	max = bdata->node_low_pfn;

	goal >>= PAGE_SHIFT;
	limit >>= PAGE_SHIFT;

	if (limit && max > limit)
		max = limit;
	if (max <= min)
		return NULL;

	step = max(align >> PAGE_SHIFT, 1UL);

	if (goal && min < goal && goal < max)
		start = ALIGN(goal, step);
	else
		start = ALIGN(min, step);

	sidx = start - bdata->node_min_pfn;
	midx = max - bdata->node_min_pfn;

	if (bdata->hint_idx > sidx) {
		/*
		 * Handle the valid case of sidx being zero and still
		 * catch the fallback below.
		 */
		fallback = sidx + 1;
		sidx = align_idx(bdata, bdata->hint_idx, step);
	}

	while (1) {
		int merge;
		void *region;
		unsigned long eidx, i, start_off, end_off;
find_block:
		sidx = find_next_zero_bit(bdata->node_bootmem_map, midx, sidx);
		sidx = align_idx(bdata, sidx, step);
		eidx = sidx + PFN_UP(size);

		if (sidx >= midx || eidx > midx)
			break;

		for (i = sidx; i < eidx; i++)
			if (test_bit(i, bdata->node_bootmem_map)) {
				sidx = align_idx(bdata, i, step);
				if (sidx == i)
					sidx += step;
				goto find_block;
			}

		if (bdata->last_end_off & (PAGE_SIZE - 1) &&
				PFN_DOWN(bdata->last_end_off) + 1 == sidx)
			start_off = align_off(bdata, bdata->last_end_off, align);
		else
			start_off = PFN_PHYS(sidx);

		merge = PFN_DOWN(start_off) < sidx;
		end_off = start_off + size;

		bdata->last_end_off = end_off;
		bdata->hint_idx = PFN_UP(end_off);

		/*
		 * Reserve the area now:
		 */
		if (__reserve(bdata, PFN_DOWN(start_off) + merge,
				PFN_UP(end_off), BOOTMEM_EXCLUSIVE))
			BUG();

		region = phys_to_virt(PFN_PHYS(bdata->node_min_pfn) +
				start_off);
		memset(region, 0, size);
		/*
		 * The min_count is set to 0 so that bootmem allocated blocks
		 * are never reported as leaks.
		 */
		kmemleak_alloc(region, size, 0, 0);
		return region;
	}

	if (fallback) {
		sidx = align_idx(bdata, fallback - 1, step);
		fallback = 0;
		goto find_block;
	}

	return NULL;
}

static void * __init alloc_bootmem_core(unsigned long size,
					unsigned long align,
					unsigned long goal,
					unsigned long limit)
{
	bootmem_data_t *bdata;
	void *region;

	if (WARN_ON_ONCE(slab_is_available()))
		return kzalloc(size, GFP_NOWAIT);

	list_for_each_entry(bdata, &bdata_list, list) {
		if (goal && bdata->node_low_pfn <= PFN_DOWN(goal))
			continue;
		if (limit && bdata->node_min_pfn >= PFN_DOWN(limit))
			break;

		region = alloc_bootmem_bdata(bdata, size, align, goal, limit);
		if (region)
			return region;
	}

	return NULL;
}

static void * __init ___alloc_bootmem_nopanic(unsigned long size,
					      unsigned long align,
					      unsigned long goal,
					      unsigned long limit)
{
	void *ptr;

restart:
	ptr = alloc_bootmem_core(size, align, goal, limit);
	if (ptr)
		return ptr;
	if (goal) {
		goal = 0;
		goto restart;
	}

	return NULL;
}

/**
 * __alloc_bootmem_nopanic - allocate boot memory without panicking
 * @size: size of the request in bytes
 * @align: alignment of the region
 * @goal: preferred starting address of the region
 *
 * The goal is dropped if it can not be satisfied and the allocation will
 * fall back to memory below @goal.
 *
 * Allocation may happen on any node in the system.
 *
 * Returns NULL on failure.
 */
void * __init __alloc_bootmem_nopanic(unsigned long size, unsigned long align,
					unsigned long goal)
{
	unsigned long limit = 0;

	return ___alloc_bootmem_nopanic(size, align, goal, limit);
}

static void * __init ___alloc_bootmem(unsigned long size, unsigned long align,
					unsigned long goal, unsigned long limit)
{
	void *mem = ___alloc_bootmem_nopanic(size, align, goal, limit);

	if (mem)
		return mem;
	/*
	 * Whoops, we cannot satisfy the allocation request.
	 */
	printk(KERN_ALERT "bootmem alloc of %lu bytes failed!\n", size);
	panic("Out of memory");
	return NULL;
}

/**
 * __alloc_bootmem - allocate boot memory
 * @size: size of the request in bytes
 * @align: alignment of the region
 * @goal: preferred starting address of the region
 *
 * The goal is dropped if it can not be satisfied and the allocation will
 * fall back to memory below @goal.
 *
 * Allocation may happen on any node in the system.
 *
 * The function panics if the request can not be satisfied.
 */
void * __init __alloc_bootmem(unsigned long size, unsigned long align,
			      unsigned long goal)
{
	unsigned long limit = 0;

	return ___alloc_bootmem(size, align, goal, limit);
}

void * __init ___alloc_bootmem_node_nopanic(pg_data_t *pgdat,
				unsigned long size, unsigned long align,
				unsigned long goal, unsigned long limit)
{
	void *ptr;

	if (WARN_ON_ONCE(slab_is_available()))
		return kzalloc(size, GFP_NOWAIT);
again:

	/* do not panic in alloc_bootmem_bdata() */
	if (limit && goal + size > limit)
		limit = 0;

	ptr = alloc_bootmem_bdata(pgdat->bdata, size, align, goal, limit);
	if (ptr)
		return ptr;

	ptr = alloc_bootmem_core(size, align, goal, limit);
	if (ptr)
		return ptr;

	if (goal) {
		goal = 0;
		goto again;
	}

	return NULL;
}

void * __init __alloc_bootmem_node_nopanic(pg_data_t *pgdat, unsigned long size,
				   unsigned long align, unsigned long goal)
{
	if (WARN_ON_ONCE(slab_is_available()))
		return kzalloc_node(size, GFP_NOWAIT, pgdat->node_id);

	return ___alloc_bootmem_node_nopanic(pgdat, size, align, goal, 0);
}

void * __init ___alloc_bootmem_node(pg_data_t *pgdat, unsigned long size,
				    unsigned long align, unsigned long goal,
				    unsigned long limit)
{
	void *ptr;

	ptr = ___alloc_bootmem_node_nopanic(pgdat, size, align, goal, 0);
	if (ptr)
		return ptr;

	printk(KERN_ALERT "bootmem alloc of %lu bytes failed!\n", size);
	panic("Out of memory");
	return NULL;
}

/**
 * __alloc_bootmem_node - allocate boot memory from a specific node
 * @pgdat: node to allocate from
 * @size: size of the request in bytes
 * @align: alignment of the region
 * @goal: preferred starting address of the region
 *
 * The goal is dropped if it can not be satisfied and the allocation will
 * fall back to memory below @goal.
 *
 * Allocation may fall back to any node in the system if the specified node
 * can not hold the requested memory.
 *
 * The function panics if the request can not be satisfied.
 */
void * __init __alloc_bootmem_node(pg_data_t *pgdat, unsigned long size,
				   unsigned long align, unsigned long goal)
{
	if (WARN_ON_ONCE(slab_is_available()))
		return kzalloc_node(size, GFP_NOWAIT, pgdat->node_id);

	return  ___alloc_bootmem_node(pgdat, size, align, goal, 0);
}

void * __init __alloc_bootmem_node_high(pg_data_t *pgdat, unsigned long size,
				   unsigned long align, unsigned long goal)
{
#ifdef MAX_DMA32_PFN
	unsigned long end_pfn;

	if (WARN_ON_ONCE(slab_is_available()))
		return kzalloc_node(size, GFP_NOWAIT, pgdat->node_id);

	/* update goal according ...MAX_DMA32_PFN */
	end_pfn = pgdat_end_pfn(pgdat);

	if (end_pfn > MAX_DMA32_PFN + (128 >> (20 - PAGE_SHIFT)) &&
	    (goal >> PAGE_SHIFT) < MAX_DMA32_PFN) {
		void *ptr;
		unsigned long new_goal;

		new_goal = MAX_DMA32_PFN << PAGE_SHIFT;
		ptr = alloc_bootmem_bdata(pgdat->bdata, size, align,
						 new_goal, 0);
		if (ptr)
			return ptr;
	}
#endif

	return __alloc_bootmem_node(pgdat, size, align, goal);

}

#ifndef ARCH_LOW_ADDRESS_LIMIT
#define ARCH_LOW_ADDRESS_LIMIT	0xffffffffUL
#endif

/**
 * __alloc_bootmem_low - allocate low boot memory
 * @size: size of the request in bytes
 * @align: alignment of the region
 * @goal: preferred starting address of the region
 *
 * The goal is dropped if it can not be satisfied and the allocation will
 * fall back to memory below @goal.
 *
 * Allocation may happen on any node in the system.
 *
 * The function panics if the request can not be satisfied.
 */
void * __init __alloc_bootmem_low(unsigned long size, unsigned long align,
				  unsigned long goal)
{
	return ___alloc_bootmem(size, align, goal, ARCH_LOW_ADDRESS_LIMIT);
}

void * __init __alloc_bootmem_low_nopanic(unsigned long size,
					  unsigned long align,
					  unsigned long goal)
{
	return ___alloc_bootmem_nopanic(size, align, goal,
					ARCH_LOW_ADDRESS_LIMIT);
}

/**
 * __alloc_bootmem_low_node - allocate low boot memory from a specific node
 * @pgdat: node to allocate from
 * @size: size of the request in bytes
 * @align: alignment of the region
 * @goal: preferred starting address of the region
 *
 * The goal is dropped if it can not be satisfied and the allocation will
 * fall back to memory below @goal.
 *
 * Allocation may fall back to any node in the system if the specified node
 * can not hold the requested memory.
 *
 * The function panics if the request can not be satisfied.
 */
void * __init __alloc_bootmem_low_node(pg_data_t *pgdat, unsigned long size,
				       unsigned long align, unsigned long goal)
{
	if (WARN_ON_ONCE(slab_is_available()))
		return kzalloc_node(size, GFP_NOWAIT, pgdat->node_id);

	return ___alloc_bootmem_node(pgdat, size, align,
				     goal, ARCH_LOW_ADDRESS_LIMIT);
}
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